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SEMI S23 Application Guide and Total Equivalent Energy (TEE) CalcII User’s Guide

International SEMATECH Manufacturing Initiative Technology Transfer #06094783D-ENG

© 2011 International SEMATECH Manufacturing Initiative, Inc.

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SEMI S23 Application Guide and Total Equivalent Energy (TEE) CalcII User’s Guide

Technology Transfer #06094783D-ENG International SEMATECH Manufacturing Initiative

October 29, 2010

Abstract: This user’s guide supplements SEMI S23-0708, Guide for Conservation of Energy, Utilities, and Materials Used by Semiconductor Manufacturing Equipment, by providing guidance in the selection and use of utility measurement instruments and recommendations for resource reduction. This revision includes instructions for using the current S23 Total Equivalent Energy Calculator (TEE CalcII), which converts various semiconductor manufacturing equipment utility consumption rates into equivalent annual electrical energy usage. The data gathered and calculations made are based on the SEMI S23 energy efficiency and roadmapping guidelines. This revision of the TEE Calculator incorporates input from member companies and includes many new features.

ISMI FURNISHES THE GUIDE "AS-IS" AND WITHOUT ANY EXPRESSED OR IMPLIED WARRANTY OF ANY KIND AND HEREBY EXPRESSLY DISCLAIMS ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. ISMI WILL HAVE NO LIABILITY WITH RESPECT TO ANY FAILURE OF THE GUIDE. ISMI WILL NOT BE LIABLE FOR ANY LOSS OF PROFIT, LOSS OF USE, INTERRUPTION OF BUSINESS OR DIRECT, INCIDENTAL, CONSEQUENTIAL OR SPECIAL DAMAGES, FOR PERSONAL OR PROPERTY INJURY ARISING FROM THE USE OF THIS GUIDE.

Keywords: Energy Use Reduction, Environmental Standards

Authors: Ralph M. Cohen

Approvals: James Beasley, Project Manager Ron Remke, Program Manager Jope Draina, Director Laurie Modrey, Technology Transfer Team Leader

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ISMI Technology Transfer #06094783D-ENG

Table of Contents

1 EXECUTIVE SUMMARY .....................................................................................................1

2 BACKGROUND.....................................................................................................................1

3 RECOMMENDED PRACTICES FOR UTILITY MEASUREMENT ..................................2 3.1 Recommended Practices for Utility Measurement .........................................................2

3.1.1 Liquid Flow Rate.................................................................................................2 3.1.2 Exhaust, Makeup Air, and Circulating Airflow Rate..........................................6 3.1.3 Compressed Gas (Air, Nitrogen, Vacuum, etc.) Flow Rate..............................10 3.1.4 Fluid Temperature Measurement (Liquid and Gaseous) ..................................12 3.1.5 Fluid Pressure Measurement (Liquid and Gaseous) .........................................14 3.1.6 Heat Dissipation to Space .................................................................................17 3.1.7 Electrical Power ................................................................................................18

3.2 Recommended Practice for Equipment Testing............................................................19 3.2.1 Establishing the Test Plan .................................................................................19 3.2.2 Guidance on Testing Procedures and Data Reporting ......................................21 3.2.3 S23 TEE Report Content...................................................................................24 3.2.4 Data Collection Methods/Analysis/Assumptions .............................................25

3.3 Recommended Practices for Reducing Utility Usage...................................................26 3.3.1 Chilled Water ....................................................................................................26 3.3.2 Process Cooling Water (PCW)..........................................................................27 3.3.3 Compressed Gas................................................................................................27 3.3.4 Exhaust..............................................................................................................28 3.3.5 Fan/Filter Selection (Minienvironment) ...........................................................29 3.3.6 Optimizing Pipe and Duct Size .........................................................................30 3.3.7 Electricity ..........................................................................................................30

3.4 Recommended Practices for Specific Equipment .........................................................30 3.4.1 Role of Economics ............................................................................................30 3.4.2 Process vs. Idle Mode .......................................................................................31 3.4.3 Liquid Pumps ....................................................................................................31 3.4.4 Packaged Chillers and Heat Exchangers...........................................................32 3.4.5 Power Supplies/RF Generators .........................................................................33 3.4.6 Heat Exchangers................................................................................................33 3.4.7 Fans and Ductwork ...........................................................................................33 3.4.8 Filters ................................................................................................................34 3.4.9 Minienvironments .............................................................................................34

4 USING THE TEE CALCII UTILITY-TO-ENERGY CONVERSION TOOL.....................37 4.1 S23 TEE Calculator Overview......................................................................................37

4.1.1 Similarities to TEE CalcI ..................................................................................37 4.1.2 Changes from TEE CalcI ..................................................................................37

4.2 S23 TEE Calculator Software Requirements and Installation Details..........................38 4.3 Basic Steps to Use the S23 TEE Calculator..................................................................40 4.4 Instructions for Using the S23 TEE Calculator.............................................................41

4.4.1 S23 TEE Calculator Homepage View...............................................................42 4.4.2 Creating Equipment ..........................................................................................42 4.4.3 Creating a Component ......................................................................................49

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Technology Transfer #06094783D-ENG ISMI

4.4.4 Energy Conversion Factors ...............................................................................53 4.4.5 Creating a Report ..............................................................................................58 4.4.6 Providing feedback............................................................................................66 4.4.7 Documentation ..................................................................................................67

4.5 Revision Control ...........................................................................................................67 4.6 Flow Diagrams ..............................................................................................................67

5 REFERENCES......................................................................................................................69

APPENDIX A – SAMPLE TEE EQUIPMENT REPORT ............................................................70

List of Figures

Figure 1 Equipment/Component/Sub-Component Relationship ..............................................2

Figure 2 Liquid Rotameter........................................................................................................3

Figure 3 Installed Paddlewheel Transmitter .............................................................................4

Figure 4 Paddlewheel Flow Transmitters .................................................................................5

Figure 5 Example of a Rectangular Duct Velocity Traverse Points Using the Log-T Rule ............................................................................................................................7

Figure 6 Example of a Round Duct Velocity Traverse Points Using the Log-Linear Rule ............................................................................................................................7

Figure 7 Pitot Tube Cross Section and Schematic....................................................................9

Figure 8 Examples of Several Types of MFMs ......................................................................11

Figure 9 Typical RTD With Cable for Connecting to Transmitter/Data Logger ....................13

Figure 10 Typical Multi-Channel Data Logger With Removable Memory Card.....................13

Figure 11 Examples of High Accuracy Test Gauges ................................................................15

Figure 12 Example of Magnetically Coupled Aneroid Bellows Differential Pressure Gauge .......................................................................................................................16

Figure 13 Illustrations of Heat Burden .....................................................................................17

Figure 14 Relationship Among Sub-Components, Components, and Equipment....................21

Figure 15 Request Access to the TEE Calculator .....................................................................39

Figure 16 Log-in Screen/Access Code Window.......................................................................40

Figure 17 S23 TEE Calculator Home Window ........................................................................41

Figure 18 Equipment “Add New” Window..............................................................................43

Figure 19 Equipment “Add New” Window, Highlighting Process, Idle, Standby, and Shutdown Percentage Fields ....................................................................................44

Figure 20 Adding/Removing Components from Equipment and Viewing Components .........45

Figure 21 Searching Equipment Data Base ..............................................................................45

Figure 22 Deleting Private Equipment (Not Shared) ...............................................................46

Figure 23 Shared Equipment Cannot be Deleted or Edited......................................................47

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Figure 24 Equipment Web Share Options, Company Share View ...........................................48

Figure 25 Equipment Window, Categories Tab View...............................................................49

Figure 26 Component Window.................................................................................................50

Figure 27 Example of Component Input Data..........................................................................51

Figure 28 Component Data Input Window...............................................................................52

Figure 29 Energy Conversion Factors Window for Gaseous Fluids ........................................53

Figure 30 Energy Conversion Factors Window for Liquid Fluids ...........................................54

Figure 31 HVAC ECF Window ................................................................................................55

Figure 32 Add New ECF Set Window .....................................................................................56

Figure 33 Typical ECF Calculator Window .............................................................................57

Figure 34 ECF Share Window..................................................................................................58

Figure 35 Report Type Selection ..............................................................................................59

Figure 36 Compare Equipment Graphically Window ..............................................................60

Figure 37 Equipment Comparison Graph and PDF Export Function.......................................60

Figure 38 Equipment TEE Report Window..............................................................................61

Figure 39 TEE Equipment Report Export Options...................................................................62

Figure 40 Component Comparison Component Selection Window.........................................63

Figure 41 Example of a Component Comparison Report.........................................................64

Figure 42 Equipment Comparison Report Equipment Selection Window...............................65

Figure 43 Equipment Category Report Category Selection Window.......................................66

Figure 44 Feedback Window ....................................................................................................67

Figure 45 Creating a User Account ..........................................................................................67

Figure 46 Creating Components and Equipment Flow Diagram .............................................68

Figure 47 Creating Reports Flow Diagram ..............................................................................68

List of Tables

Table 1 SEMI S23 Utilities to be Measured............................................................................1

Table 2 Comparison of Liquid Flow Measurement Methods .................................................5

Table 3 Point Grid for Velocity Traverse in Rectangular and Round Ducts ...........................6

Table 4 Comparison of Air Flow Measurement Methods.....................................................10

Table 5 Comparison of Gas Flow Measurement Methods....................................................12

Table 6 Comparison of Temperature Measurement Methods ...............................................14

Table 7 Comparison of Pressure Measurement Methods......................................................16

Table 8 Summary of the Types of Measurements Required by S23 vs. Equipment Types ........................................................................................................................19

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Table 9 Level of Accuracy for S23 Measurements That Would be Acceptable to Semiconductor Manufacturers .................................................................................20

Table 10 Typical Component-Level Utility Data Required for the TEE Calculator...............22

Table 11 Component-Level Typical Calculation Performed by the TEE Calculator..............23

Table 12 SEMI Recommended Additional Data .....................................................................25

Table 13 Typical High Efficiency Fan Filter Unit Performance .............................................29

Table 14 Motor Power vs. Efficiency......................................................................................33

Table 15 Flow vs. Velocity and Friction Loss by Pipe Size....................................................36

Table 16 Information Provided in TEE Report .......................................................................63

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Acknowledgments

The TEE CalcII calculator was created primarily by Tabatha Sikes of Handsdown Software with engineering and technical direction provided by the author. Valuable suggestions were provided by member companies with special thanks to Mark Denome of Applied Materials.

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1 EXECUTIVE SUMMARY

This user’s guide supplements SEMI S23-0708, Guide for Conservation of Energy, Utilities, and Materials Used by Semiconductor Manufacturing Equipment, by providing guidance in the selection and use of utility measurement instruments. Each category of measurement instrument is reviewed including practical considerations when using and correcting for non-standard conditions. Comparison tables highlighting relative cost, accuracy, and ease of use or installation are also included, and acceptable measurement accuracies are tabulated. Recommendations for resource reduction are provided, considering the facility system and the impacts of the key parameters influencing resource use for that facility.

Instructions are also included for using the International SEMATECH Manufacturing Initiative (ISMI) S23 Total Equivalent Energy Calculator (TEE CalcII), a desktop software application provided by ISMI. This revision incorporates input from member companies and includes many new features..

2 BACKGROUND

Three documents were used in developing this guide:1

SEMI E6-0303, Guide for Semiconductor Equipment Installation, prescribes the process for semiconductor equipment manufacturers to collect and report utility data in processing and idle modes.

SEMI S23-0708, Guide for Conservation of Energy, Utilities, and Materials Used by Semiconductor Manufacturing Equipment, prescribes a method to collect, analyze, and report energy-consuming semiconductor manufacturing equipment utility data as well as a method to convert energy consumption into kW-hour/cubic meter equivalents. It also defines broad energy conservation strategies.

Semiconductor Equipment Association of Japan (SEAJ) E-002E, Guideline for Energy Quantification, provides additional detail and clarification augmenting SEMI S23 as well as useful reporting templates and examples.

SEMI S23 recommends, at a minimum, that users measure the utilities listed in Table 1 while the equipment is processing material and while it is idling.

Table 1 SEMI S23 Utilities to be Measured

Utility or Material Basic Use Rate Metrics and Units Related SEMI Standard E6

Sections (0303 Version)

Exhaust Pressure (Pa); Flow (m3/hr); Inlet Temp (°C); Outlet Temp (°C)

Section 18

Vacuum Pressure (Pa); Flow (m3/hr) Section 17

Dry Air / Nitrogen (N2) Pressure (Pa); Flow (m3/hr) Section 16

Cooling Water Supply Pressure (KPa); Return Pressure (KPa); Flow (l/hr); Inlet Temp (°C); Outlet Temp (°C)

Section 13

Ultrapure Water (UPW)A Purity Requirements; Inlet Temp (°C); Flow (l/hr) Section 13

Electricity Real PowerB (Watts) Section 12

Note A: “Ultrapure Water” is also known as “Deionized Water.” Note B: “Real Power” is also known as “True Power.”

1 Copyrighted SEMI standards material is used by permission of SEMI.

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As shown in Figure 1, equipment is composed of components, which are composed of sub-components. This convention is important when using the S23 TEE Calculator because the user “builds” equipment by defining and then selecting components. The TEE Calculator provides input only at the equipment and component level; sub-components cannot be defined separately from a component.

Equipment

Component 1

Sub-component 1(vacuum pump & power supply)

Power, N2, POW

Sub-component 2(chamber)

Exhaust & Power

Component 2

Sub-component 3(vacuum pump & power supply)

Power, N2, POW

Sub-component 4(chamber)

Exhaust & Power

Example: Process vs. Idle and Sub-component/Component/Equipment Relationship for equipment comprised of two components.

Figure 1 Equipment/Component/Sub-Component Relationship

3 RECOMMENDED PRACTICES FOR UTILITY MEASUREMENT

The following section summarizes measurement methods, including recommended practices, for persons fulfilling SEMI E6 and SEMI S23 reporting requirements. It describes measurements of temperature, pressure, liquid and gaseous flow, and electrical power. This section also discusses the relative ease of application, accuracy of each method, and relative costs.

3.1 Recommended Practices for Utility Measurement

3.1.1 Liquid Flow Rate

Four measuring devices are commonly used to determine the flow rate of liquids in pipes for systems such as ultrapure water, process cooling water, and chilled water flow. Ultrasonic, paddlewheel/turbine, and Pitot-type velocity measuring instruments are affected by fluid turbulence. A minimum of 7.5 pipe diameters of straight pipe upstream of the sensor and 3 pipe diameters downstream are needed. If the sensing element is located downstream of several 90° bends in different planes, the minimum straight pipe upstream increases to 18 pipe diameters. The ASME PTC 19.5, Flow Measurement, provides detailed recommendations for locating the sensor to minimize measurement error.


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3.1.1.1 Ultrasonic

Ultrasonic devices measure the transit time of acoustic signals in the flowing fluid stream. The energy is directed through the pipe wall from a transmitter affixed to the pipe and subsequently detected by a receiver also affixed to the pipe. This method has the advantage of being non-intrusive (i.e., the sensors are clamped temporarily to the outside of the pipe). Another advantage is that the signal can be easily data-logged, recorded, or transmitted. Some units require gas bubbles or suspended solids in the fluid stream to be able to determine the flow rate. The instrument measures velocity but can convert it to a flow rate from operator inputs of pipe size, material, and wall thickness. The pipe sizes that can be measured range from 12.7 mm to 2.5 m (1/2 inch to 100-inch) diameter. Ultrasonic flowmeters can measure flow only in rigid piping.

3.1.1.2 Rotameter (Variable Area Flow Meter)

The rotameter is the most commonly used indicating fluid flow meter in the semiconductor industry. It requires relatively little space, is reasonably accurate, and is typically inexpensive, especially in the smaller sizes. A rotameter uses a tapered, calibrated measuring column and float suspended within the column. Quality and fragility vary greatly. Units can be fabricated from extruded plastic, machined plastic, glass/bronze fitted, or glass/stainless steel fitted. The rotameter is installed in-line with the column oriented vertically. A specific flow range, specific gravity or density, viscosity, and fitting size must be specified, necessitating some attention to the application (ultrapure water [UPW]/deionized water [DIW] and process cooling water [PCW] would be considered ordinary “water”). Some units have magnetically coupled indicators that eliminate reading the float position. One needs to be aware of the part of the float to “read” as manufacturers have specific requirements (center of ball/float, bottom of ball/float, etc.). Rotameter flow rate is not easily data-logged, recorded, or transmitted to a monitoring system beyond a high or low flow limit. See Figure 2 for an example of a low cost rotameter.

Figure 2 Liquid Rotameter


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3.1.1.3 Paddlewheel

A paddlewheel flow meter is a moderate cost process measurement and control instrument. It essentially counts magnetic pulses from a rotating paddlewheel with embedded magnets in the blade ends. It works well with clean, low viscosity fluids (water). The flow sensor is installed in-line or into the branch of a “tee.” Specific gravity, viscosity, and pipe size must be selected, necessitating attention to the application. Readout can be analog or digital, and the signal can be data-logged or transmitted. Several levels of quality and features are available at commensurate costs. Long-term reliability may be an issue with some products because there are no bearings at the rotating shaft to limit wear. Turbine flow meters are similar to paddlewheel flow meters but are more accurate and reliable. Figure 3 is a drawing of a paddlewheel flow meter installed in a pipe using a thread-o-let. The rotating paddlewheel can be seen in each flow transmitter in Figure 4.

Pipe containing

liquid

Threadolet(welded to pipe wall)

Paddlewheel or turbine flowmeter (thread into threadolet)

FLOW

Figure 3 Installed Paddlewheel Transmitter


5

D

0.926 H

0.712 H

H0.500 H

0.288 H

0.563 D0.765 D0.939 D

0.061 D

0.437 D

0.235 D

0.074 H

Figure 4 Paddlewheel Flow Transmitters

3.1.1.4 Averaging Pitot Tube

The Pitot tube is a very basic method of measuring fluid velocity by measuring total and static pressure. This method is economical for larger pipes (~ 50 mm/2 inches or larger). The averaging Pitot tube simultaneously measures velocity pressure at several points within the flow stream and provides an average value that can be converted directly into a flow velocity. Knowing the pipe cross-sectional area, the flow rate can be calculated. The Pitot tube is threaded into a weldolet attached to the pipe (perpendicular to flow) and is connected to a differential pressure manometer, gauge, or transmitter with tubing. Manufacturers of these devices provide graphs to convert the pressure readings into velocity or flow. If the Pitot tube is connected to an electronic transmitter, the readings can be data-logged; otherwise, readings must be recorded manually. Long-term, it is more reliable than a turbine meter. Averaging Pitot tubes are specified for a given pipe diameter. The indicated values must compensate for the viscosity and specific gravity of the measured fluid. The sensor and tubes must be installed so that air is not trapped. The above methods of measuring liquid flow rate are summarized in Table 2.

Table 2 Comparison of Liquid Flow Measurement Methods

Type Cost Accuracy Type of Installation Ease of Setup and Operation

Ultrasonic High 2–4% Non-intrusive Difficult

Rotameter Low 0.5–5% In-line Easy

Paddlewheel Low 2% In-line or insertion Moderate

Turbine Moderate 0.25% Insertion Moderate

Averaging Pitot + Differential Pressure Transmitter (DPT) or Gauge

Low–Moderate 2–4% In-line or insertion Moderate


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3.1.2 Exhaust, Makeup Air, and Circulating Airflow Rate

The four commonly used measuring devices for determining airflow rate all measure or are used to derive the velocity or volumetric flow of the fluid. After calculating the cross-sectional area of a duct, the flow is determined using the equation Flow = Velocity Area. The hotwire anemometer, Pitot tube, and calibrated orifice plate or Venturi nozzle are useful for measuring duct velocity, while the hotwire anemometer and vane anemometer are useful for measuring the velocity across an open exhaust hood or filter faces. To measure duct velocity with a Pitot tube or hot wire anemometer, holes must be drilled into the duct wall so that the device can be positioned at each of the sampling points. Flow into or out of the hole during measurement must be restricted, and the hole should be plugged after the measurements are completed.

A general caveat when making velocity measurements in ducts or across large open faces of exhaust hoods is as follows: to be accurate, a sampling grid should be established so that velocity is measured using the log-Tchebycheff (log-T) rule for rectangular ducts and the log-linear rule for round ducts (see Figure 5 and Figure 6, respectively, for sample applications) rather than using the “center of equal areas” or measuring at a fixed interval (e.g., every 50 mm [2 inches)) across the duct. The point location is shown in Table 3. Note that the log-linear rule for circular ducts results in a point location that is not constant from the edge of the duct toward the center. This is because the points are located approximately in the center of equal concentric areas. The plane of measurement should be located 7.5 duct diameters downstream and 3 duct diameters upstream of duct disturbances for acceptable accuracy. A longer straight run from upstream obstructions improves point reading stability. Setting up correct sampling grids is discussed thoroughly in reference guides (e.g., Industrial Ventilation: A Manual of Recommended Practice published by the American Conference of Governmental Industrial Hygienists or ASHRAE Fundamentals, the 2005 edition or earlier, Section 14). One should become familiar with these recommendations to produce accurate and repeatable results. A general guideline is to measure at least 25 points in a square or rectangular duct with points no more than 15 cm (6 inches) apart. For round ducts, at least 6 points per diameter on 3 diameters that are 120° apart should be measured.

Table 3 Point Grid for Velocity Traverse in Rectangular and Round Ducts

# of Points for Traverse Lines Position Relative to Inner Wall (log-T rule for rectangular ducts)

5 0.074 0.288 0.500 0.712 0.926

6 0.061 0.235 0.437 0.563 0.765 0.939

7 0.053 0.203 0.366 0.500 0.634

0.797 0.947

# of Measuring Points per Diameter Position Relative to Inner Wall (log-Linear rule for circular ducts)

6 0.032 0.135 0.321 0.679 0.865 0.968

8 0.021 0.117 0.184 0.345 0.655 0.816

0.883 0.981

10 0.019 0.077 0.153 0.217 0.361 0.639

0.783 0.847 0.923 0.981

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D

0.926 H

0.712 H

H0.500 H

0.288 H

0.563 D0.765 D0.939 D

0.061 D

0.437 D

0.235 D

0.074 H

Figure 5 Example of a Rectangular Duct Velocity Traverse Points Using the Log-T Rule

0.032 D

0.135 D0.321 D

0.968 D

D

0.865 D

0.679 D

Figure 6 Example of a Round Duct Velocity Traverse Points Using the Log-Linear Rule


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3.1.2.1 Thermal Anemometer

This type of instrument measures velocity by determining the temperature difference between reference points: one point is the ambient air stream temperature while the other point is heated a fixed amount but is allowed to be cooled by the air flowing past it. The temperatures are measured with thermocouples, resistance temperature devices (RTDs), or thermistors. The minimum velocity capability (typically <0.05 meters/sec [mps] or 10 feet/min [fpm]) is the lowest of all the velocity instruments. However, dust and corrosive gases limit anemometers’ usefulness in process applications because of fouling. These instruments are best used to measure face velocities across exhaust hoods or filters and velocity in small ducts free of process gas. Some instruments may have data-logging capability.

3.1.2.2 Pitot Tube With Differential Pressure Gauge or Electronic Pressure Transducer

The Pitot tube with an inclined manometer, differential pressure gauge, or electronic differential pressure transducer is a very practical instrument for measuring duct velocity. The Pitot tube has one orifice that faces into the air stream that measures total pressure and others that are perpendicular to the air stream that measure static pressure. These orifices are connected to the differential pressure measuring device with flexible tubing. The algebraic difference between the two pressures is called “velocity pressure.” This can be converted to velocity by a simple formula (see ASHRAE Fundamentals or Industrial Ventilation). Figure 7 illustrates the orientation of the two orifices to the air stream and the connection of the differential gauge. The formula, derived from Bernoulli’s equation, is as follows (in Imperial units):

2/1

2

cg

VPCV Eq. [1]

where: V = Velocity (fpm) C = 136.8 (IPS conversion) VP = Velocity pressure units (inches H2O) = Air density units (lbm/ft3) gc = Gravitational constant = 32.174 lbm-ft/lbf-sec2

At standard air density (1 atmosphere and 70°F), this equation simplifies to

Eq. [2] 2/14005 VPV

If the temperature of the fluid stream is other than at standard conditions of temperature, then a density correction must be applied.

Another form of this equation using S.I. units is as follows:

2/1

000,100

000,100

293

25.1013

VP

Ps

T

BCV Eq. [3]

where: V = velocity (mps) C = 1.291 (S.I. conversion( B = Local barometric pressure (mbar) T = Air stream temperature (°K) VP = Velocity pressure units (Pascal) Ps = Duct static pressure (Pascal) and may be ignored below 2500 Pascal


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Using metric units, the equation takes the following form:

2/1

10350

10350

293

760

VP

Ps

T

BCV Eq. [4]

where: V = Velocity (mps) C = 4.05 (Metric conversion) B = Local barometric pressure (mm Hg) T = Air stream temperature (°K) VP = Velocity pressure units (mm H2O) Ps = Duct static pressure (mm H2O) and may be ignored below 250 mm H2O

Pitot tubes are available in different lengths and diameters to measure velocity in ducts of any size. The minimum velocity capability is ~3 mps (600 fpm) with an inclined manometer or magnetically coupled differential pressure gauge but lower (<0.05 mps or 100 fpm) with a sensitive differential pressure transducer. If a transducer is used, the readings may be data-logged. Because process equipment ducts are typically designed to operate in the range of 4–10 mps (800–2000 fpm), it should be possible to use the Pitot tube with an appropriate differential pressure measuring device. Pitot tube grids are also available that can be installed inside ducts to provide an average velocity pressure value for the entire duct, simultaneously, without conducting a duct traverse for each measurement. This saves data collection time. Pitot tube grids may be less precise than a Pitot tube (2% to 40% vs. 1% to 6%) because of the fundamental difference in operating principle: converting velocity pressure at each measurement point to velocity and then averaging all velocity measurements vs. averaging all velocity pressure measurements and converting them to a single velocity value.

Streamlines

Stagnation Point

Static Taps(several, equally spaced circumference)

DifferentialManometer

Figure 7 Pitot Tube Cross Section and Schematic


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3.1.2.3 Calibrated Orifice Plate or Flow Nozzle With Differential Pressure Gauge or Electronic Differential Pressure Transducer

The orifice plate or flow nozzle provides a fixed flow obstacle in the air stream. Pressures measured up- and downstream of the orifice are converted to a velocity value. The advantage of using an orifice plate is that a single measurement provides the velocity, eliminating the need to conduct a duct traverse. This is useful for permanent duct installations (e.g., in a lab). Minimum velocity capability is similar to a Pitot tube.

3.1.2.4 Revolving Vane-Anemometer

The revolving vane-anemometer has an air flow-driven, rotating wheel that induces magnetic pulses or generates a small current in an electronic circuit. The rate of the pulses or current is calibrated to the speed of the air that rotates the wheel. This instrument is a less expensive alternative to the thermal anemometer but has a minimum velocity capability of approximately 0.05 m/s (100 feet/min). It is most useful for measuring velocity on filter faces or across exhaust hood faces. The above methods for measuring air flow rate are summarized in Table 4.

Table 4 Comparison of Air Flow Measurement Methods

Type Cost Accuracy Minimum Velocity Ease of Use

Thermal Anemometer Moderate–High 2–8%* 0.05 mps (10 fpm) Moderate

Pitot Tube + DPT or Gauge Low 1–6% 0.5 mps (100 fpm) w/DPT Moderate

Orifice + DPT or Gauge Low–Moderate 1–6% 0.5 mps (100 fpm) w/DPT Easy only if orifice is pre-installed

Vane Anemometer Moderate 2–6% 0.5 mps (100 fpm) Easy

* <25 mps or 5000 fpm.

3.1.3 Compressed Gas (Air, Nitrogen, Vacuum, etc.) Flow Rate

Measuring gas flow is straightforward for bulk, compressed gases (e.g., air, nitrogen, oxygen, argon, hydrogen). The semiconductor equipment industry has generally standardized the mass flow meter (MFM) and the rotameter; however, different instruments have a markedly different effect on the cleanliness of the gas. The associated safety hazards of working with flammable and inert gases should not be overlooked.

Vacuum flow measurement is not as straightforward. Due to the low density of gas near an absolute vacuum, the velocity must be quite high to obtain a sufficient pressure drop across a Venturi or orifice to allow measurement. The pressure drop measured is proportional to the gas density; therefore, at 48.8 Torr (711 mm Hg or 28 inch Hg) vacuum, the density is ~6% that of standard conditions. Hence, to obtain a measurable differential pressure, the piping must be designed to provide a velocity of at least 12.7 mps (2500 fpm) across the Venturi or orifice.

3.1.3.1 Thermal Mass Flow Meter (MFM)

MFMs may also be used for measuring flow rates, if properly selected. These are the most accurate instruments for gas flow measurement discussed here. They also are available in a non-contaminating design. MFMs determine the flow by measuring the temperature difference between two RTDs in the flow stream (or a sidestream) as a result of electrically heating the stream. In-line process gas mass flow controllers (MFCs) are available up to 25.4 mm (1 inch) outside diameter (OD) (~2,500 lpm range). Larger in-line MFMs, as well as insertion units (tapped into the side of piping), are available in sizes from 9.5–203 mm (0.375 inch–8 inch)

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diameter. MFMs require a known and controlled upstream pressure; all but the sidestream type MFM/MFC requires uniform velocity (10–12 equivalent diameters of straight tubing run). MFMs or MFCs provide an electronic digital readout and can be interfaced to data log. Figure 8 shows several typical mass flow meters.

Figure 8 Examples of Several Types of MFMs

3.1.3.2 Rotameter (Variable Area Flow Meter)

Gas rotameters are similar to their liquid rotameter counterparts (see Section 3.1.1.2). Accurate results depend on density corrections. Gas temperature and pressure must be known and specified to calibrate the rotameter. If the stream being measured is at a different temperature or pressure than the specified values for the rotameter or is a different gas, then corrections need to be applied to the indicated values. For example, if a rotameter is specified for compressed air at 20°C (68°F ) and 483 kPa (70 psig) but will be used to measure compressed air at 30°C (86°F) and 690 kPa (100 psig), then the difference in density between the two conditions would cause an error. The density of air at 30°C and 690 kPa is 30% greater than the density of air at 20°C and 483 kPa. The equation governing flow through a rotameter shows that flow varies approximately as the square root of the inverse of gas density. Therefore, in this example, a 30% increase in density gives a rotameter-indicated flow 14% greater than the actual flow. Since the flow equation also depends on several other factors (e.g., float dimensions and density, rotameter tube cross-sectional area), the user should have the supplier provide corrections and calibrations for the specific rotameter being used. Because the specific gravity of air and nitrogen (at standard temperature and pressure) varies by 3.4%, the error in using a rotameter calibrated for air to measure nitrogen (or vice versa) would be ~1.7%.

The decision to use a rotameter for gases of a given purity should be based on the application and the user’s need to maintain a given purity level at the equipment.

3.1.3.3 Ultrasonic (Non-Intrusive)

Ultrasonic measurements are non-intrusive. The minimum size tube that currently can be measured is 19 mm (0.75 inch) O.D. To obtain the best accuracy, the pressure and temperature of the gas must be known as well as tube wall thickness and material. The tubing must be rigid. While an ultrasonic flow meter can be useful for measuring flow through the facility mains and


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sub-mains, it has limited use in equipment measurement until the minimum size capability is reduced to 12.7 mm (0.5 inch) O.D. or smaller. Accuracy is lagging in smaller sizes; for 6 inches and smaller, accuracy is only 4–10%. These instruments have data-logging capability. The above methods for measuring gas flow rate are summarized in Table 5.

Table 5 Comparison of Gas Flow Measurement Methods

Type Cost Accuracy Cleanliness Ease of Install/

Operation

MFM/MFC Moderate 1.5–2% High Moderate

Rotameter Low 0.5–5% Low Easy

Ultrasonic High 2–10% High Difficult

3.1.4 Fluid Temperature Measurement (Liquid and Gaseous)

Temperature is measured by a change in a material’s electrical properties, expansion of a liquid, expansion of metals, or emission of infrared light from the object. Methods using these principles are highlighted below.

Installing the temperature elements directly in the flow stream provides the quickest response and greatest accuracy. However, to be able to remove temperature elements from flow streams without shutting down and draining the piping, thermowells need to be installed in the piping. Proper installation involves orientation with respect to the flow stream, well immersion length, well immersion in the flow stream, well diameter vs. pipe diameter, and temperature element length in relation to thermowell length. An immersion length of 11.4–26.7 cm (4.5–10.5 inches) is adequate for semiconductor equipment facility applications. If the temperature being measured differs from the surroundings by more than 30°C (50°F), then the portion of the thermowell external to the pipe must be minimized and insulated. See ASME PTC 19.3-2004, Temperature Measurement Instruments and Apparatus, for further guidance. Since equipment cooling lines are small compared to the thermowell diameter, consideration should be given to oversizing the piping containing the thermowells to prevent excessive pressure drops.

3.1.4.1 RTDs With Transmitter and Data Logger

Platinum resistance temperature detectors are stable and accurate with a standard of 100 at 0°C. Since fluid temperatures vary during process ramps (up and down), data logging and graphing are more convenient than recording data manually. The transmitter consists of a bridge circuit with an analog output (e.g., 4–20 mA) that is scaled to the RTD temperature range. The data can be recorded using a data logger and then downloaded to a computer hard drive through a suitable interface card (analog to digital). (See Figure 9 and Figure 10 for typical examples.) Resolution to 0.05°C or 0.1°F is adequate. Due to multiple sources of error (RTD, transmitter, analog:digital [A:D] converter), the accuracy of the measurement system should be evaluated before collecting data. To do this, all elements are connected and then the indicated value of the temperature compared to a standard (e.g., a precision bulb thermometer or calibrated RTD).

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Figure 9 Typical RTD With Cable for Connecting to Transmitter/Data Logger

Figure 10 Typical Multi-Channel Data Logger With Removable Memory Card

RTD with Transmitter and Digital Readout

This setup is similar to those with a data logger except that the data must be recorded manually. Sufficient points should be taken over the time period to assure that the minimum and maximum for each stream throughout the processing cycle are recorded.

Thermistor

Sintered metallic oxides are used to measure temperature because their resistance decreases dramatically with rising temperatures. These instruments can use transmitters, digital readouts, and data loggers similar to RTD instruments.

Precision Glass Bulb Thermometer

The precision glass bulb thermometer offers a fully manual, low cost approach. Proper installation is important, including attention to heat transfer within the thermowell. Accuracy can be better than a thermocouple if the selected range matches the measured range but not as good as an RTD. Since glass is fragile and mercury is hazardous, one must use caution with bulb thermometers. Colored alcohol-filled thermometers offer an alternative to mercury.

Bi-Metallic Dial Thermometer

While convenient and inexpensive, accuracy is inadequate for the precise work of equipment characterization. The bi-metallic thermometer is ideal for manually monitoring equipment to verify operation within an allowable range.


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Infrared (IR) Thermometer

Two of the issues limiting IR thermography from being useful in this application are that surface emissivity (a value must be entered in the thermometer setup) must be known and that accuracy varies with temperature. Its primary advantage is that temperatures can be ascertained without physical contact; however, accuracy is inadequate for equipment characterization. IR thermometers can be useful in studies of insulation effectiveness and comparisons among objects. Accuracy can be improved by calibrating with a more accurate technology.

Thermocouple with Potentiometer or A:D Converter

The type “T” thermocouple, using copper and constantan, has a range of -150 to 370°C. It produces ~50 mV per °C. It must be calibrated using a precise standard. Using thermocouples is slightly more difficult than RTDs or thermistors due to the care required to wire and the need to use a reference junction or an electronic substitute.

The above methods for measuring temperature are summarized in Table 6.

Table 6 Comparison of Temperature Measurement Methods

Type Cost Accuracy Ease of Installation Ease

Operation

RTD w/ Data Logger High ±0.1°C (±0.2°F) Moderate–Difficult Moderate

RTD w/ Digital Readout Medium–High ±0.1°C (±0.2°F) Moderate Easy

Thermistor w/Digital Readout Medium–High ±0.1°C (±0.2°F) Moderate Easy

Precision Bulb Thermometer Low–Medium ±0.3°C (±0.5°F) Easy Easy

Bi-Metallic Dial Low ±0.5°C (±1.0°F) Easy Easy

Infrared Medium–High ~0.3–1°C (~0.5–2°F)

Easy–No Installation Easy–Moderate

Thermocouple w/ A:D Converter and Digital Readout

Medium–High ±0.1°C (±0.2°F) Moderate Moderate

3.1.5 Fluid Pressure Measurement (Liquid and Gaseous)

Pressure measurement is more segmented by application than temperature or flow measurements. Pressure measurements in semiconductor fab equipment must span from near vacuum to pressures of 10 atmospheres or more, both liquids and gases, and from “dirty” (exhaust streams or process cooling) to ultra high purity (process gases or DIW). Instruments that can be used include bourdon gauges, strain gauges, aneroid bellows gauges, or manometers.

Care must be taken to measure the true “static” pressure of the exhaust duct and to exclude any component of the velocity pressure. Static pressure taps for air streams are fabricated from stainless steel tubing and have several small holes drilled circumferentially around the part of the tube that is positioned parallel to the flow stream. Placement in non-turbulent regions of the duct is also important. Steady readings are indicative of placement out of these turbulent regions.

3.1.5.1 Bourdon Tube Gauge (for High Pressure Liquid or Gaseous)

These gauges are available in a range of accuracy from “gross” (> 5%) to precise (0.1%) with cost adjusted accordingly. As gauges become more accurate, the size typically increases and the geared movement coupling the bourdon tube to the indicating needle is more precise (see

15

Figure 11 for examples of precision gauges). The faceplate for more precise gauges is designed to eliminate parallax reading error as well. Bourdon tube gauges are inherently stream-contaminating due to the dead end passage, material, and manufacturing process that does not fully inert the Bourdon tube during welding; attempts have been made to produce “clean” gauges that may be adequate for some applications.

When measuring pressure in a UPW stream, a diaphragm isolator is used between the gauge and the stream to eliminate the “deadleg” that allows bacteria growth.

Figure 11 Examples of High Accuracy Test Gauges

3.1.5.2 Strain Gauge Pressure Transducer With Digital Readout (for High Pressure Gaseous and High Purity)

This is the one technology that can cover virtually all semiconductor fab equipment needs for SEMI S23 measurements, although it is also the most expensive. Because different instrument ranges and purity specifications are required, several instruments are needed. For high purity or corrosive applications, 316 stainless or a high nickel content alloy wetted parts should be specified as well as internal surface cleaning by electropolishing. Data logging can be substituted for the digital readout, if desired.

3.1.5.3 Magnetically Coupled Aneroid Bellows Differential Pressure Gauge (i.e., Magnehelic) (for Low Pressure Gaseous)

This gauge offers a low differential pressure measuring capability (down to 125 Pascal or 0.5 inch w.c.). It is useful for measuring exhaust and supply air pressures when specified with a suitable range. Because the static pressure capability of some of these instruments is low (~1 atmosphere), they must NOT be used in higher pressure applications. Figure 12 shows this type of gauge. This gauge makes water-filled column manometers obsolete in that they are reasonably accurate, easier to use, and cost only slightly more. The wetted parts are not


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Figure 12 Example of Magnetically Coupled Aneroid Bellows Differential Pressure Gauge

compatible with highly corrosive fluid streams but in a dead-end service application (e.g., exhaust static pressure), deterioration is either a non-issue or occurs very slowly. The general classification of “aneroid bellows gauge” includes instruments designed to measure low differential pressures with high static pressures (10 atmospheres or more) that are useful when measuring the pressure drop across a Pitot tube, a calibrated orifice, or a Venturi to determine a gaseous flow rate (see Sections 3.1.2.2 and 3.1.2.3).

3.1.5.4 Column Manometer (Water- or Mercury-Filled U-Tube or Inclined)

This can be considered a “bedrock” technology: it is basic, simple, reliable, accurate, and inexpensive. There are some caveats, however. If the range of the gauge is incorrect, the water or mercury can be either “blown out” or sucked into the process stream with undesirable or even hazardous results. Also, this technology is designated for low purity only since contaminating streams (water or mercury) are in direct “communication” through the sensing tube with the process stream.

The above methods for measuring pressure are summarized in Table 7.

Table 7 Comparison of Pressure Measurement Methods

Type Application Cost Accuracy Cleanliness

Precision Bourdon Tube Gauge

High pressure liquid or gas Moderate–High 0.1% Low

Strain Gauge Transducer w/Digital Readout

Low or high purity liquid or gas, exhaust or supply air

High 0.01–3% Low–High

Aneroid or Magnetically Coupled Bellows Gauge

Low pressure, low purity gas; exhaust

Moderate 0.5–6% (4% if > 150 Pa)

Low

Water-Filled Column Manometer

Exhaust or supply air Low–Moderate 1–5% Low

Mercury-Filled Column Manometer

High pressure liquid or gas Low–Moderate 1–5% Low

Bourdon Tube Gauge High pressure liquid or gas Low 1–5% Low–Medium


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3.1.6 Heat Dissipation to Space

Knowledge of how heat dissipates into a space is useful in equipment evaluation and important to facility designers. All cleanrooms are designed with a finite capacity to remove heat. If equipment is introduced into the equipment set that dissipates more heat to the space than the facility can accommodate in that footprint, the temperature of the space will be above specification locally. Since heat is more economically removed by cooling water than by cool air, it is preferable to remove most of the waste heat by cooling water.

Heat dissipation into a space can be measured in two ways. The first is direct, while the second is indirect. The approach used is governed by the equipment configuration as well as the facility in which to make measurements.

The heat dissipated into the space is also referred to as “heat burden” in SEMI S23 and the S23 TEE Calculator. Heat burden is represented in Figure 13.

Equipment

+ Energy

= Heat

Some of the heat is removed by heat exhaust and the process cooling water system.

Therefore, heat into the cleanroom minus heat removed by exhaust and process cooling water system equals the required heat burden to the cleanroom.

If the heat burden is not removed with air conditioning, the temperature in the cleanroom will rise.

Figure 13 Illustrations of Heat Burden


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3.1.6.1 Indirect

To determine heat dissipation indirectly, the total power consumed by the equipment or produced through a chemical reaction is first measured and then all measurable power paths emanating from the equipment, except for the heat radiated or convected to the space, are subtracted from that value. Algebraically, power to space [kW] = power in [kW] + exothermic reaction [kW] (if any) – cooling water dissipation [kW] (if any) – exhaust dissipation [kW] (if any). Because some of these values will vary through the processing cycle, they should all be data-logged to calculate total annual usage.

SEMI S23 (Table 2) provides ECFs for determining annual kilowatt-hours (kWh) of energy used to remove heat by exhaust or water, plus a “burden” to be used for the central chilled water plant energy consumption. Table R1-3 provides an example applying the same ECFs to calculate annual kWh. These factors are derived from the basic thermodynamic equation: Heat = mass flow rate specific heat temperature change.

3.1.6.2 Direct

If all of the air flowing across the equipment can be measured for flow and temperature rise, then the heat dissipation can be measured directly. Since this is not the prescribed method in SEMI S23, an explanation is outside the scope of this document.

3.1.7 Electrical Power

If process equipment has a three-phase electrical load other than pure resistance (heating element, incandescent lighting), then a three-phase A-C power meter must be used to accurately measure what is termed “real power” or “effective power.” This device measures both the real power (wattmeter) and the apparent power (volts amps 1.732 for 3-phase power) and determines the ratio between them, known as the “power factor.” Since a customer pays for the “real power,” it is desirable for the power factor to be near unity (PF = 1). When only single-phase power is required for the equipment, an ammeter and voltmeter can be used to measure the power consumption.

Because power consumption often varies throughout the equipment’s production steps, the electrical power should be recorded with a data logger during a full cycle to calculate an average and determine peaks for facility design.

Instruments that cannot perform the measurements in less than 250 msec should not be used because they will not be able to adequately characterize the dynamic nature of the electrical load presented by processing equipment.

The voltage and current measurements should be made with digital instruments capable of reporting the true root mean square (RMS) value of the voltage and current waveforms, respectively. The power meter should support and report voltage and current measurements simultaneously with other measurements. Analog, moving-coil, electrodynamics, or other types of voltage or current measurement are not suitable for applications in which a full characterization of a load is necessary. The meter should be used according to the manufacturer’s instructions, including instrument placement and appropriate settings.

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3.2 Recommended Practice for Equipment Testing

3.2.1 Establishing the Test Plan

3.2.1.1 Specific Utilities

The utilities of interest are only those listed in SEMI S23 0708 that have listed energy conversion factors (ECFs). Specifically, they are exhaust, vacuum, nitrogen, oil free air, high pressure oil free air, chiller cooled process cooling water, tower cooled process cooling water, ambient deionized water, and hot deionized water. Manufacturing equipment may have additional utilities. These can be measured and reported but are not currently relevant to SEMI S23.

3.2.1.2 Test Points and Required Accuracy

SEMI S23 0708 provides guidance on the minimum set of required measurement points. This is the same list of points provided in the S23 TEE Energy Calculator (see Table 1). Table 8 also lists typical measuring points by equipment type.

Table 8 Summary of the Types of Measurements Required by S23 vs. Equipment Types

Measurement Points (Equipment Type)

N2, Dry Air (flow rate)

Vacuum (flow rate)

Cooling Water (flow rate, temp

in/out

UPW/DIW (use flow

rate)

Exhaust (flow rate,

temp exiting equip.)

Electrical Power

Fuel Used (heat rate)

Process Equipment including Power Supply/RF Generator

X X X X X X X

Vacuum Pump X X X

Heat Exchanger + Pump X X

Chiller + Pump X X

Environmental Chamber X X

Circulation Fan X

Exhaust Fan X X

The user must decide whether utilities will be measured for the entire piece of process equipment or for each component, sub-component, or a combination of components and sub-components. Measuring to the sub-component level will give a level of data that may allow greater understanding but at a higher cost and requiring more analysis. Ease of measuring in different locations within the equipment will also bear on the decision as well as how the data will be used. Absolute guidance cannot be given.

If the user wishes to verify that their utility operating parameters are similar to those used to derive the ECFs then additional data for each utility must be measured. Refer to SEMI S23 0708. The new version of the TEE Calculator does not support use of non-standard ECFs.

More information about instrumentation and required accuracy is provided in all of Section 3.1, earlier in this document. The reader should also refer to the table of contents.

Table 9 includes recommended instrument accuracy.

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Table 9 Level of Accuracy for S23 Measurements That Would be Acceptable to Semiconductor Manufacturers

Parameter Accuracy Parameter Accuracy

Liquid Flow 5% Temperature 0.3°C/0.5°F

Air Flow 6% Liquid pressure** 3%

Gas Flow 5% Gaseous pressure <150 Pa** 6%

Power 5% Gaseous pressure >150 Pa** 4%

Note: ** not required to use the S23 TEE Calculator

When setting up the instruments for automatic data logging, ensure that the instruments are ranged properly to measure flows incurred during both idle and processing and that sampling rate is adequate to capture short term fluctuations. If step changes in measured parameters from idle to process are infrequent, manual data logging may be possible.

3.2.1.3 Location of Points

To locate measuring points (liquid, gas, exhaust) far enough from bends that turbulence does not adversely affect the readings, follow the guidance in Sections 3.1.1 and 3.1.2.

Making electrical connections for voltage and current measurements may be challenging if there are many sub-components and space is limited. Select test probes appropriate to the situation. Temporary installation of current transformers may be preferable to clamp-on amperage probes, and hard wiring for voltage measurement may be preferable to alligator clips or probe tips.

In all cases, plan for each measured point and buy or rent the necessary equipment before the test. Once all measurement points have been identified, mark the location of each test point on a drawing to ensure that points have not been omitted.

3.2.1.4 Test Equipment

List all the test equipment used in the test report. Include manufacturer, model, utility measured, measurement range, most recent calibration date, and recommended calibration interval. Also, include data loggers or chart recorders.

3.2.1.5 Calibration

The frequency and method of calibration vary with the instrument. Equipment manufacturers may have their own internal calibration labs and standards. If not, independent standards labs can be used. The history of the instrument’s stability and the instrument manufacturer’s recommendation should be used to guide calibration frequency.

Order precision instruments with calibration curves. Compare subsequent calibrations to those curves. Calibrate instruments at least annually, although more frequent calibrations can be done to establish instrument stability.

3.2.1.6 Safety

Safety will not be addressed specifically. It is assumed that each company and person working with electricity, gases, exhaust, and fluids is trained to recognize hazards and take precautions to protect themselves from electrocution, asphyxiation, eye injury, and poisoning that can result from an improper methodology.

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3.2.2 Guidance on Testing Procedures and Data Reporting

3.2.2.1 Data Needed to Use the TEE Calculator

The TEE Calculator has been configured to accommodate data measured at the component and equipment level. If components are broken into sub-components, each sub-component is treated as a distinct component. See the example in Figure 14.

Component 1 Component 2

Sub-component 1

(vacuum pump & power supply)

Power, N2, PCW

Sub-component 2

(chamber)Exhaust &

Power

Sub-component 3(vacuum pump

and power supply)

Power, N2, PCW

Sub-component 4

(chamber)Exhaust &

Power

User measures: % time at max/min flow or power and max/min flow or power for

each component utility down to Sub-component

Equipment 1: Twocomponent tool

Power, N2, exhaust, PCW

Define: % process/idle for each component and max./min. flow or power for each

component utility. TEE Calculator sums all component utilities, properly ratioed for

process/idle/percent.

Figure 14 Relationship Among Sub-Components, Components, and Equipment

To ensure measurements of the total equivalent energy to process a given number of wafers are accurate, measure energy from all sub-components and components as simultaneously as possible. The measured data must capture the minimum and maximum power or utility flow and the duration or percentage of time at the minimum and maximum rate for each component as it is not expected that every component is loaded for an identical percentage of the processing cycle. The required data may be more easily understood from the sample spreadsheets. See also Section 4, which explains data entry for the TEE Calculator. See Table 10 and Table 11.

TEE Calculator users can either collect data at the component level only and have the TEE Calculator sum the data for all defined equipment components OR collect data at the equipment level only, but not both. The fewest data collection points are likely with a sampling scheme that measures at the equipment level, but practical reasons may govern choosing to measure at the component level (access, routing of individual gas and power lines to each component, etc.).


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After completing calculations at the component level, the TEE is summed for the defined piece of equipment consisting of one or more components. The heat burden is then calculated based on the user-defined equipment-level process/idle/other percentages. The calculator was configured to calculate heat burden based on the SEMI S23 format of equipment basis. Consequently, the user should enter process/idle/other percentages when entering equipment information.

If the user does not have max/min flow and power information and wants to use data that have already been averaged over the processing cycle, a value of 100% is entered for “processing” and 0% for “idle” along with the average value measured or calculated entered in the “Max flow/power” blanks in the user input form (shown as Col. C in Table 11). An “Idling flow/power” must still be entered (shown as Col E in Table 10,) for the calculator to properly calculate the idle TEE if the component has idle time.

Table 10 Typical Component-Level Utility Data Required for the TEE Calculator

Test Component 1 80% Processing % of year

15% Idling % of year

5% Other % of year

See notes

% times, are for a full process cycle

% Time at Max Flow/Power While

Processing Max Flow/Power

% Time at Idling or Min Flow/Power While

Processing Idling

Flow/Power Unit

Col B Col C Col D Col E

Exhaust 50% 450 50% 200 M3/hr

N2 90% 10 10% 5 M3/hr

PV 90% 5 10% 2.5 M3/hr

Dry Air 90% 10 10% 5 M3/hr

HP Dry Air 100% 5 0% 3 M3/hr

PCW chilled 100% 2.3 0% M3/hr

PCW evap 100% 1.1 0% M3/hr

UPW 100% 10 0% M3/hr

Hot UPW 100% 5 0% M3/hr

Mean real power 90% 100 10% 30 kW

Note1 User provides measured data. SEMI S23-0708, recommends using values of 70% processing, 25% idle, and 5% inactive, but any relevant values can be used.

Note 2 Max/Min flow is calculated from either component data or measured directly at equipment.

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Table 11 Component-Level Typical Calculation Performed by the TEE Calculator

See notes below

Average Processing Flow/Power

Idling Flow/Power ECF

Processing TEE [kWh/hr]

Idling TEE [kWh/hr]

Processing TEE Annual [kWh/yr]

Idling TEE Annual [kWh/yr

Col H Col I Col J Col K Col L Col M Col N

Math:

Col B Col C + Col D

Col E Col E Constants Col H Col J Col I Col J

Col K % Processing x

hrs/yr Col L %

Idle hrs/yr

Exhaust 325 200 0.0037 1.2 0.7 8427 972

N2 9.5 5 0.25 2.4 1.3 16644 1643

PV 4.75 2.5 0.06 0.3 0.2 1997 197

Dry Air 9.5 5 0.147 1.4 0.7 9787 966

HP Dry Air 5 3 0.175 0.9 0.5 6132 690

PCW Chilled

2.3 0 1.563 3.6 0.0 25193 0

PCW Evap 1.1 0 0.26 0.3 0.0 2004 0

UPW 10 0 9 90.0 0.0 630720 0

Hot UPW 5 0 92.2 461.0 0.0 3230688 0

Mean Real Power

93 30 1 93 30 651744 39420

Note1 Column (“Col”) references to Col B through E refer to columns noted in Table 11.

Note2 TEE Calculator performs calculations in Col H, I, K, L, M, and N.

3.2.2.2 Sampling

Data can be recorded manually or automatically (with a data logger). Any instrument with a current or voltage output can be connected to a data logger or a computer can be used as a data logger through an electronic interface card.

Automatic data collection is preferred if the process variable changes frequently during the process cycle and if unattended data collection and digital data manipulation are preferred.

The frequency of sampling is based on the stability of the process variable being measured. The degree of stability can be determined using analog instruments before deciding how often to log datapoints. Alternatively, a high data-logging rate (e.g., every 5–15 seconds for non-electrical points and milliseconds for electrical points) can be set and then adjusted based on an analysis of the stability of the logged points.

Be aware of the time constant of the instrument (i.e., how long the instrument takes to reach equilibrium for a given measured value). For example, pressure readings reach stability almost instantaneously, but temperatures may take 30 seconds or longer. If a process variable changes more quickly than an instrument can accurately measure it or record the value, then the data will be inaccurate.

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3.2.2.3 Test Duration

To comply with SEMI S23, the test should last long enough to process 10 substrates or, if not processing substrates, then at least 30 minutes. Minimum and maximum values should be determined for each utility as well as a time split (in %) between the minimum and maximum values. Idle time measurement between processing cycles should also be at least 30 minutes and an average value determined. Because setting up the test is expensive, measure long enough to be certain that the data quality is acceptable.

3.2.2.4 Acceptable Test Methods

See Section 3.2.1.2 and Table 9.

3.2.2.5 Data Analysis/Reporting Format (Tabular, Graphical, Supporting Documentation, Dealing With Non-Linear Graphical Data)

Download data collected with data loggers to spreadsheets and graph it with easily understood datapoint labels with units and scales included on all axes. Similarly, transcribe any data collected manually to spreadsheets and graph as above.

Where data are non-linear, use “best fit” techniques to establish average values for the time interval or average the logged values from the spreadsheets and report the average values calculated for the time intervals. Do not average values that cannot be averaged: e.g., velocity pressure cannot be averaged, but velocity can be.

3.2.3 S23 TEE Report Content

3.2.3.1 Management Summary

Describe only the equipment, the equipment configuration, main processing parameters, and TEE result for the equipment, including TEE per wafer pass. If this was a follow-up study, describe what changed in the equipment and the net change in TEE.

3.2.3.2 Equipment and Test Scope

Describe the subcomponents, components, and equipment to a level adequate to be able to differentiate this equipment from other competitive equipment and to be able to later refer to the report and understand exactly what was tested. Include a block diagram showing the interconnection between components and sub-components with the utilities measured clearly defined. Show utility line sizes (wire, duct, tube, pipe) for all utilities measured.

Describe the “process cycle” for this equipment: how long the equipment operate while measuring utility flow rates and the amount of product (numbers of wafers) processed during that time.

Table R1-1 from SEMI S23-0708 recommends data to be recorded for each equipment test.

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Table 12 SEMI Recommended Additional Data

Data Title Description

Date When the measurements were taken.

Equipment Under Test (EUT) The equipment from which the measurements were taken. Provide information such as general description, model number, and serial number.

EUT Configuration The configuration of the equipment during the measurements, such as sub-systems that were or were not used and optional hardware that was installed.

Test Location Where the measurement testing was done such as the particular test laboratory or manufacturing location.

Principal Test Personnel The principal personnel involved in developing the test plan and conducting the testing.

Test Recipe The recipe used when conducting the test.

Test Throughput (per hour) How many substrates or other material quantity was processed per hour during the test.

Throughput Calculation Method How is throughput determined?

Wafer Size What size wafer is processed by the equipment.

Test Duration How long the equipment was operating for gathering the test data.

Test Setup How the several pieces of test equipment were connected to the EUT.

Test Equipment and Relevant Calibration Information for measuring:

Exhaust Vacuum Dry Air Nitrogen Process Gas (at or above atmospheric pressure) Process Gas (below atmospheric pressure) Process Solids Process Liquids Cooling Water Ultra Pure Water (UPW) Electricity Heat Load High Pressure Dry Air Hot UPW

The test equipment that was used to measure the use rate of each utility or material and its relevant calibration information such as when the test equipment was last calibrated and when it should be calibrated again.

Note: Republished with permission from Semiconductor Equipment and Materials International, Inc. (SEMI) © 2009.

3.2.4 Data Collection Methods/Analysis/Assumptions

3.2.4.1 Methods

List the instrumentation used to collect data (make, model, most recent calibration date and estimated or stated accuracy). Provide diagrams, schematics, and/or photographs showing where the instruments were connected. Explain the data collection plan (frequency of sampling, sampling time, and total duration for each measured value), and the way average values were determined from the measured data.

List any assumptions used in data collection. For example, power consumption was constant during processing or temperature was constant during processing.

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3.2.4.2 Results

Provide raw data clearly marked to indicate the datapoint measured. For example, “Vacuum pump #1 PCW flow [gpm]” is acceptable, but “FT105-3” is not acceptable unless a key explains the abbreviated labels. If data loggers are used, raw data will be printouts indicating date, time, and value from start of sampling to end of sampling. Graphs are an acceptable and a preferred substitute for tabular data. Clearly show the average value (minimum/maximum or process/idle) determined for each measured variable in the table or graph.

If the measured data was entered into the calculator and TEE per year was determined, then the report should include that value as well as a calculation of TEE per wafer pass. Calculate this value by dividing Total Equivalent Energy (kWh/year) derived by the TEE Calculator by the number of wafer passes that would occur during the year.

3.2.4.3 Discussion/Summary

Using the data collected and output from the TEE Calculator, summarize the results with graphs of each measured utility and provide minimum and maximum flow rates, power consumption, and duration of minimum and maximum flow rates and power consumption during the processing cycle.

Include graphs of total equivalent energy by utility, a Pareto of total equivalent energy by component, pie chart comparisons between idle and processing total equivalent energy and comparison to other tools by the same manufacturer (total equivalent energy and process vs. idle.

3.2.4.4 Recommendations

Include any observations about ways to reduce the total equivalent energy usage, problems encountered making measurements and their resolution, and any other comments pertinent to testing the equipment or the results.

3.3 Recommended Practices for Reducing Utility Usage

3.3.1 Chilled Water

Few equipment manufacturers use this facility system directly. Typically, it is plumbed throughout the wafer fab for the air conditioning system (cooling and dehumidification) and to the process cooling water heat exchanger. The supply temperature is selected based on need and economics. It has a setpoint, typically between 36°F and 55°F (2.2°C and 12.8°C). One or two systems may have different temperature setpoints, as well: one toward the lower end of the range and one toward the higher end of the range. Because the efficiency of central chilled water systems is better than that of small packaged chillers (kW power consumed per kW cooling effect), direct use would save energy but might increase the total cost due to additional piping systems in the sub-fab. Using chilled water that has a temperature below the dewpoint of the surrounding air will cause condensation on equipment surfaces unless the surfaces are adequately insulated.

Another way to reduce energy consumption would be for process equipment designers to standardize a higher inlet temperature requirement for process cooling water (increase from 10–12.8°C (50–55°F) to 15.6–18.3°C (60–65°F) so that a higher temperature chilled water system can be used to remove heat from the process cooling water loop. This will be successful only if all suppliers can raise their specified maximum inlet temperature. For a 760 liter/sec (lps) (12,000 gal/min [gpm]) system operating with a 3.9°C (7°F) temperature differential,

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~ 6 million kWh/year would be saved due to the higher efficiency of removing the heat with a 10°C (55°F) chilled water loop rather than a 3.9°C (39°F) loop.

3.3.2 Process Cooling Water (PCW)

When a PCW system or systems are isolated from the facility chilled water system, the PCW system or systems can operate at a higher temperature than the chilled water system, have a higher differential pressure between supply and return, and be chemically isolated to assure fluid cleanliness and corrosion treatment adapted to a system containing copper, aluminum, and ferrous metals. Three principal factors govern efficiency in using PCW systems to remove heat from equipment.

3.3.2.1 Supply/Return Temperature

If a higher process equipment inlet temperature is applied, the process equipment heat exchanger may need to be enlarged or the process equipment chiller may need to be modified to accept the higher inlet temperature. If the temperature differential between the equipment supply and return is increased, the flow rate can be reduced, saving both pump energy and ultimately allowing the piping size to be reduced. While a typical facility chilled water system design temperature differential is 8.9°C (16°F), the PCW average design differential for the past 25 years has remained at 4.2°C (7.5°F). For a 760 liter/sec (12,000 gpm) system, this adds 1.8 million kWh/year in pumping energy and prevents reducing the flow rate to 360 liter/sec (5625 gpm).

3.3.2.2 Supply/Return Pressure

PCW systems require approximately 310 kPa (45 psi) differential to overcome equipment piping and internal restrictions. This is more than 2X the differential of facility system equipment. If all equipment could reduce flow restrictions to a lower common value (e.g., 207 kPa [30 psi]), then the differential pressure of the system could be lowered. For a 760 lps (12,000 gpm) system, this would save 1.2 million kWh/year in pumping energy.

Can the PCW supply temperature, differential temperature, and differential pressure requirements for equipment be improved? What would the impact be on heat exchanger size and how would the changes impact equipment cost and performance?

3.3.2.3 Flow Control

PCW flow should be restricted to maintain the minimum flow required to adequately remove equipment-generated heat at all times. Currently, not all equipment have thermostatic or process:idle flow reducing controls. Since the PCW system controls typically respond to reduced flow demand by reducing supply pump speed, controlling equipment flow can save some energy. However, this is the least important of the three factors.

3.3.3 Compressed Gas

The gases of interest from an energy conservation standpoint are those for which electrical energy is used for on-site compression rather than cryogenic gases that develop pressure by evaporating cryogenic liquid. The compressed air system and on-site nitrogen plant are significant energy users. Work at SEMATECH and elsewhere has highlighted opportunities for consumption reduction, pressure reduction, and replacement of nitrogen with clean, dry compressed air.

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3.3.3.1 Pressure at Point of Connection (POC)

For nitrogen generated on site and compressed air, the required pressure at the POC drives energy consumption. An additional 103 kPa (15-psi) of pressure requires ~3% more power. Since the incremental cost is low (< $15K for a 212 m3/min [7500 scfm] compressed air system at $ 0.06/kwh), efforts to reduce supply pressure may be unjustified. However, if a single piece of equipment is developed with a supply pressure requirement above the currently installed facility capability, it then dictates that an entirely new system is added to factories with a major capital cost component as well as a higher operating cost.


Since gas systems operate to match demand, efforts to reduce flow will result in savings approximately proportional to the reduction. The degree to which this is true depends on how the facility system is designed to accommodate start-up and low flow conditions. Centrifugal compressors have turndown limits (15% typically), which suggests that flow reduction at the equipment may be negated by an oversized facility system or one that is still being ramped with a partially fitted out fab. Rotary screw compressors have superior turndown capability (~ 80%) but are slightly less efficient, overall.

Central process vacuum compressors can also be retrofitted with variable speed drives so that the system responds to flow reduction by reducing capacity using a slower motor speed to maintain a constant system setpoint pressure.

3.3.4 Exhaust

The energy consumed to exhaust equipment is proportional to the quantity of exhaust and the pressure required to move the exhaust air stream. The basic principle of minimizing exhaust flow is to fully isolate the hazard and then minimize the aperture between the hazard and the operator. Beyond that, there are several techniques for minimizing flow, e.g., multi-sided slots around tank surfaces, push-pull exhaust, full-containment with robotic manipulation, etc. References such as Industrial Ventilation: A Manual of Recommended Practice, published by the American Conference of Governmental Industrial Hygienists, 1998, or ASHRAE Handbook: HVAC Applications, 1999 edition, Chapter 29, may be helpful. Equipment suppliers should not apply arbitrary rules such as “providing so many air changes per hour” or “so many meters/second face velocity;” instead the industry should use computational fluid dynamics (CFD) to model equipment in development or use tracer gas analysis (see SEMI F15-93) to validate exhaust rates for operating equipment. SEMATECH has undertaken several exhaust reduction and optimization studies (see Section 5).

Using a heat exchanger to recover heat from heat exhaust is not cost-effective unless the exhaust stream is very hot, 65°C (150°F). However, if the stream has no other contaminants than heat and perhaps some particulates, it may be possible to discharge the warm stream into the cleanroom return plenum or into another adjacent space that requires outside air.

Dampers should be inspected for in-leakage, especially blast gate dampers.

3.3.4.1 Pressure at POC

Once flow is minimized, suction pressure at the POC can be investigated. Currently, the typical facility allowance for equipment is (-)500 Pascal (-2 inch w.c.). Constant pressure should be maintained automatically by an end-of-duct pressure control loop and variable speed fans. Unless all equipment can achieve an across-the-board pressure reduction, however, there will be

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little or no benefit to total facility exhaust energy consumption since normally equipment are connected to a common system. If a single piece of equipment or several pieces of equipment have a requirement greater than the norm, it may be beneficial to redesign that equipment to provide a booster fan for the equipment(s) to make up for the deficiency.

Several references (e.g., ASHRAE Fundamentals, the 2005 edition, Chapter 35 or SMACNA HVAC Duct System Design) provide information on the impact of duct transitions and fitting geometry on pressure loss.

For an exhaust system of 4250 m3/min (150,000 cfm), a flow reduction of 10% and an operating pressure reduction of 62.5 Pa (0.25 inch w.c.) would result in an annual savings of ~360,000 kWh.


Controlling the flow (stopping if inactive) in equipment or hoods is not done as frequently in semiconductor manufacturing as in research laboratories. Reasons are many, including the small percentage of the total energy bill (<10%), often 24/7 operation, relatively high cost of controls, corrosiveness of exhaust on flow control devices, and the need to minimize system perturbation from equipment changing flow. Flow reduction in inactive or periodically used equipment presents a significant challenge. Since all equipment connected to a variable flow exhaust system must have individual flow controls whether or not the equipment will use variable flow, economics can be greatly improved by identifying and isolating the variable flow equipment to a dedicated variable flow exhaust system.

To evaluate the cost effectiveness of flow reduction strategies, the annual cost per unit of exhaust (e.g., Euros/CMH or $/cfm, etc.) must first be determined. The capital cost should also be ascertained if the flow reduction could be applied to new construction. Since reduced exhaust directly impacts fresh air makeup, the impact on energy and capital cost is considerable.

3.3.5 Fan/Filter Selection (Minienvironment)

Minienvironment efficiency can be addressed in terms of watts per unit of airflow (cubic meters/sec or cubic feet/minute). The factors governing “real power” consumption are fan and motor efficiency, losses in the flow control mechanism (typically either a variable speed motor control or pressure drop across a throttling damper), and filter pressure drop. A filter’s pressure drop depends on the total filter media area (not just face area) and face velocity.

Table 13 shows the performance parameters for a typical high efficiency fan filter unit.

Another useful parameter to define is cost per unit of airflow rate. Given this parameter and power per unit of airflow, one can make an intelligent decision on changes that reduce power consumption but increase total cost.

Table 13 Typical High Efficiency Fan Filter Unit Performance

Parameter Metric Units English Units

Face Velocity 0.406 m/s 80 fpm

Static Pressure 154 Pa 0.62 inch w.c.

Unit Power Consumption 208 W 208 W

Power/Unit Air Flow 0.10 W/m3/hour 0.17 W/cfm

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3.3.6 Optimizing Pipe and Duct Size

The size of the duct or piping inside the equipment as well as between the equipment and lateral plays a large part in dictating the required pressure differential or “driving force” across the equipment for PCW and exhaust. Owners could develop a Pareto of required exhaust pressure or fluid pressure/differential pressure by equipment for their equipment sets. They then can work with equipment suppliers to determine what extra cost would be incurred to improve the differential pressure requirement by an incremental amount corresponding to an across-the-fab energy reduction. A favorable scenario would be one in which improvements to a few pieces of equipment would significantly reduce system differential pressure. For each system, the object would be to have the least extra capital cost for the greatest energy savings.

3.3.7 Electricity

3.3.7.1 Supply Voltage

Generally, supplying equipment at a higher standard voltage is preferred to a lower voltage. For example, 480 V is preferred to 208 V. Higher voltage eliminates an extra transformation step and transformation loss; reduces the number of required facility substations, saving capital and space; and allows longer wire runs due to the lower voltage drop per length. It also can reduce conductor size (since power is proportional to voltage and current), saving cost and space. Three-phase power is a standard for 208 V and above. Motors should be specified as three-phase due to their lower cost and superior efficiency.

3.3.7.2 Variable Speed Drives (VSDs)

Electrical VSDs operate by stopping the flow of current to the device for a part of the sinusoidal cycle. Reliability is acceptable, and cost has been declining as more have been installed. They are available in ~0.1–500 kW (or fractional horsepower to hundreds of horsepower) and both single- and three-phase. Speed is set either by hand or by a control signal input. Because current is frequently interrupted, VSDs tend to decrease motor-bearing life. This is overcome by specifying “VSD-compatible motors.” Electrical arcing across the bearing has sometimes resulted in rapid wear and early failure. Installing motor shaft grounds or insulating the bearings from the motor frames can overcome this problem. These issues and solutions are well understood by motor and drive specialists.

3.4 Recommended Practices for Specific Equipment

3.4.1 Role of Economics

Nearly every equipment improvement that reduces energy consumption has a corresponding cost increase. Although some design improvements are nearly “free,” most equipment improvement costs need to be justified. Each user has a method to determine cost effectiveness (e.g., simple payback, internal rate of return, or net present value). The supplier’s role is to characterize and report the cost impacts to the end user—capital, installation, maintenance, consumables, equipment life, etc.—and the corresponding annual energy use reduction, allowing the user to perform an economic analysis.

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3.4.2 Process vs. Idle Mode

Equipment does not process wafers continuously. Hence, turning off or reducing the flow of utilities when they are not needed in both process and idle modes is ideal; however, not all utilities ramp up and down with usage. For example, reducing the flow of bulk gases, electricity, and cooling saves money (although there are limits to turndown that come into play during a new plant startup). But unless expensive pressure or flow controllers are used at each piece of equipment, exhaust is difficult to turn down without impacting the flow from adjacent equipment.

In general, the equipment supplier should assess opportunities to reduce utilities during idle mode, work with the end user to determine potential cost savings, and then determine whether the cost savings will be sufficient to pay for the cost of the additional controls to limit gas, exhaust, cooling water, or vacuum flow or to reduce speed of vacuum pumps or cooling pump motors.

3.4.3 Liquid Pumps

3.4.3.1 Type of Pump vs. Energy Consumption

Numerous types of pumps move fluids, e.g., centrifugal, diaphragm, and reciprocating positive displacement (piston or plunger). The object in selecting one for minimum energy consumption should be to minimize excess capacity and head (pressure) and maximize pump efficiency. For example, compare an air-operated diaphragm pump to a centrifugal pump for a clean water application. Using one supplier of each (diaphragm vs. centrifugal), at a flow of 0.63 lps (10 gpm) and 241 kPa (35 psig) head, the diaphragm pump using compressed air requires ~4X as much electrical energy to operate—(6.13 lps [13 scfm] of air at 655 kPa [95 psig] and 3.1 kW or 0.24 kW/scfm for compressed air vs. 0.74 kW or a ¾ horsepower motor). Installation and operating advantages of each type of pump as well as total capital cost for the pumps and installation would need to be considered to make the appropriate decision. Also, for the same type of pump, efficiency can vary considerably; it is recommended to check several manufacturers before making a selection.

3.4.3.2 Adequate Pressure vs. Excessive Pressure

Calculating the exact equipment pressure and flow requirement is seldom possible, often resulting in oversized pumps. To absorb the excess capacity, a discharge valve is throttled. This inefficiency can be overcome two ways:

1. “Trim” (machine to a smaller diameter) the impeller to the exact requirement. This makes sense if there is time to do the necessary testing after installing, there are sufficient numbers of pumps in identical applications, or there is a large amount of energy to be saved.

2. Add a variable speed drive to reduce the motor/pump speed to the required flow/pressure. This is commonly done in facilities cooling and heating systems. Some motor-drive combinations produce significantly more acoustic noise than others; testing or experience should guide the selection of these components (see Section 3.1.7).

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3.4.4 Packaged Chillers and Heat Exchangers

3.4.4.1 Individual Chillers vs. Central System With Heat Exchanger

Most suppliers of individual chiller packages also offer heat exchanger packages. If only cooling is needed and the required supply temperature is high enough (typically 15–20°C or 59–68°F), a heat exchanger package can be considered using PCW to provide the cooling. Package refrigeration is required for lower temperatures.

A non-conventional but more energy efficient solution would be to consider using the facility-chilled water system instead of PCW to provide direct cooling through a heat exchanger. The facility-chilled water system typically supplies chilled water between 2.2–12.8°C (36–55°F) vs. PCW at 11–16°C (52–61°F) (all temperatures depend on the user’s preference). With a 3°C (~5°F) approach for the “warm” side of the heat exchanger, using the facility-chilled water system with a heat exchanger, one could obtain 9–15°C (48–59°F) fluid for the equipment. The facility-chilled water system uses less electrical energy than the packaged chiller, perhaps one-third to one-half less, but adds capital cost to pipe the water to the equipment heat exchangers. Pipe insulation would be needed on the lower temperature piping and heat exchanger surfaces to prevent condensation.

3.4.4.2 Simultaneous Heating and Cooling

Some packaged temperature control units can both cool and heat the process fluid. Energy efficient design precludes simultaneous heating and cooling. Also, when in heating mode, refrigeration compressors and PCW flow for condensing should ideally be “off.”

3.4.4.3 Capacity Modulation

In order of preference (best to worst) are variable speed compressors, cycling compressors, unloading compressors, and hot gas bypass.

3.4.4.4 Condensing Temperature

The PCW setpoint of 11–16°C (52–61°F) is quite a low temperature to be used for refrigerant condensing. Some pumping energy may be saved with only minor impact on packaged chiller power by installing thermostatic valves to control the chiller package condensing temperature at a higher value.

Installing a separate condenser water loop for the equipment chiller packages and any other process equipment that can operate at a higher temperature could be evaluated. In some locales, a closed circuit evaporative cooler can be used. For example, with site wet bulb temperatures of 18–24°C (65–75°F), 24–30°C (75–86°F), cooling water could be provided. The negative impact of operating cost on the packaged chillers from raising the condenser supply temperature and adding capital cost would need to be compared to the positive impact of reducing the facility-chilled water plant and PCW system capacities.

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3.4.5 Power Supplies/RF Generators

3.4.5.1 Improved Efficiency of ACDC Converters (Rectification and Regulation)

Power supplies could be sized more accurately to their loads; units are often oversized by a factor of 2 to 3 decreasing efficiency from ~80% to 70% or less. The trend in processing has been to decrease power consumption, but power supply sizing does not reflect that trend. Advances in ACDC rectifiers (higher frequency and improved amplifier designs) are not necessarily being applied. Cost/benefit analyses for improvements should be provided by suppliers.

3.4.6 Heat Exchangers

3.4.6.1 Pressure Drop

Industrial heat exchanger applications are normally specified at a 35–103 kPa (5–15 psi) differential. Plate and frame heat exchangers can achieve pressure differentials on the low end of this range. However, there is no benefit in specifying and designing a heat exchanger package with a low pressure differential on the cold side when parallel circuits with equipment are installed on the same PCW system with pressure differentials 2–3X as great. There is a benefit, however, in having a low pressure differential specified for the “hot side” of the exchanger since it is a separately pumped circuit between the equipment and the heat exchanger.

3.4.6.2 Temperature Differential

The average PCW system temperature differential is ~3°C (5.5°F), which necessitates an excessively high circulation rate. A reasonable target would be 8.3°C (15°F) or higher. Some equipment is already achieving this.

3.4.7 Fans and Ductwork

3.4.7.1 Motor and Fan Efficiency

Efficiency of AC electric squirrel cage induction motors varies by speed, size, and type (open or enclosed). ANSI/ASHRAE/IESNA Standard 90.1-2004, Energy Standard for Buildings Except Low-Rise Residential Buildings, provides values that would be an excellent target (see Table 14).

Table 14 Motor Power vs. Efficiency

Type Open Open Open Enclosed Enclosed Enclosed

Speed (RPM) 3600 1800 1200 3600 1800 1200

kW (HP)

0.75 (1) 82.5 80.0 75.5 82.5 80.0

1.1 (1.5) 82.5 84.0 84.0 82.5 84.0 85.5

1.5 (2) 84.0 84.0 85.5 84.0 84.0 86.5

2.25 (3) 84.0 86.5 85.5 85.5 87.5 87.5

3.75 (5) 85.5 87.5 87.5 87.5 87.5 87.5

5.6 (7.5) 87.5 88.5 88.5 88.5 89.5 89.5

7.5 (10) 88.5 89.5 90.2 89.5 89.5 89.5

11.2 (15) 89.5 91.0 90.2 90.2 91.0 90.2

Note: Table derived from ANSI/ASHRAE/IESNA Standard 90.1-2004.

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The mechanical efficiency of fans varies with fan type, size, speed, air density, and pressure developed. Small fans used in minienvironments are low in efficiency (<50%), while larger fans used in environmental chamber circulation schemes could approach 70% under ideal conditions. Although not available in very small sizes, backward curved and backward curved airfoil-bladed fans are the most efficient. The best approach to optimizing fan efficiency is to compare different manufacturer’s offerings with respect to features, capacity, pressure capability, noise, power consumption, and cost for the same application. Then a technical and cost analysis can be completed.

3.4.7.2 Duct Design

Power to operate a fan is proportional to the air flow rate and the pressure developed. While flow rate may be fixed by the process, the pressure developed not only consists of the resistance to flow of the required system elements such as filters and cooling heat transfer surfaces but also is influenced by how well the system is designed to minimize pressure losses as the air flows through the system. Duct size and smoothness, elbow radius, transition length and geometry, length of the straight duct entering and leaving a fan and location of elbows at the fan entrance and discharge, damper size and type, and velocity through system elements (filters, cooling heat transfer surface) all influence system pressure loss. In general, lower velocity reduces friction losses—and hence fan power and operating cost—but increases capital cost and component size. A tradeoff analysis should be completed. Evaluation is not straightforward, but excellent references are available. The SMACNA Duct System Design and ASHRAE Fundamentals are two suggested references. A positive outcome from duct design improvements is an across-the-board reduction in exhaust system pressure achieved by a pressure requirement reduction for equipment with the highest exhaust pressure requirements. Note that reductions by equipment NOT currently driving the system pressure will not reduce facility operating costs and will not be cost-effective.

3.4.7.3 Variable Speed Application

Wherever a damper is used to throttle excess pressure (e.g., mini-environment or environmental chamber), applying a variable speed drive to the fan motor should be considered. Fan power varies approximately as the cube of speed; therefore, a small reduction in speed can save considerable power (25% speed reduction = 50 + % power reduction).

3.4.8 Filters

Filter pressure drop is governed by the type of media, air velocity through the media, and total area of the media. From an energy consumption standpoint, a low initial pressure drop and low face velocity are desired outcomes. Normally, improving these increases capital cost by increasing the filter depth or the total area of the filter pack and possibly equipment size. Filter manufacturers also offer a variety of filter media at different efficiencies vs. pressure drop and cost. Once the costs and impacts on power consumption are known, a cost effectiveness analysis can be completed.

3.4.9 Minienvironments

Since minienvironments consist of fans and filters, the discussion of fan efficiency, pressure drop vs. filter depth/filter design, and variable speed drive applies to efforts to decrease power consumption.

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3.4.9.1 Environmental Chambers

Since environmental chambers consist of fans, filters, chillers, heat exchangers, and ductwork, the discussion of fan efficiency, pressure drop vs. filter depth/filter design, ductwork, packaged chillers, heat exchangers, and variable speed drive applies to efforts to decrease power consumption.

3.4.9.2 Cooling/Heating/Humidity Control Methodology

The elements of an environmental chamber temperature control system consist of an air cooling/dehumidifying heat exchanger, an air reheater, a humidifier, a refrigeration system, piping, controls, and the above discussed fans, filters, and duct. Because functionality is not an issue with current products, inquiry should focus on a few key areas that impact energy consumption:

How is the cooling heat exchanger optimized?

Is the cooling coil optimized with respect to fin spacing and fin profile vs. number of rows to achieve the lowest airside pressure drop? Is the coil face area large enough to optimize the pressure drop vs. first cost?

Do humidifying and dehumidifying occur simultaneously?

Is there a need to dehumidify at all if the space dewpoint, setpoint, and variation are identical to the environmental chamber dewpoint, setpoint, and variation?

How is humidification accomplished?

What is the kWh per mass of water evaporated? Is the most efficient means of humidification being used?

How is the air reheated?

Is any waste heat from refrigeration used?

How is refrigeration capacity controlled?

Are there multiple compressors with unloading (e.g., 2 stage 2 compressors or 2 stage 1 compressor)? Is hot gas bypass used? What increment of capacity is unloaded by hot gas bypass (e.g., last 25% or 50%)?

What is the efficiency of the refrigeration process as defined by the coefficient of performance?

ANSI/ASHRAE/IESNA Standard 90.1-2004, Energy Standard for Buildings Except Low-Rise Residential Buildings, recommends a target COP between 5.0 and 6.0 for small centrifugal chillers. Environmental chamber refrigeration systems are not likely to achieve these results, but the methodology for comparison is applicable. Comparing work “out”—or in this case, cooling effect to energy “in”—will allow comparisons among suppliers and configurations.

3.4.9.3 Piping

Piping and duct optimization are similar in approach (see Section 3.4.7). Facility designers have developed guidance for sizing larger pipes and ducts for cost-effective designs. This is usually in either maximum velocity per pipe/duct size or pressure drop per unit length. Developing general guidance for equipment internal piping based on a cost-benefit analysis may be complicated by

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the impact of enlarging the pipe and duct (or airway) within the equipment. However, suppliers should still try to optimize capital cost against energy consumption.

Design information is available in many supplier catalogs, technical guides, and handbooks (e.g., +GF+ Plastics, Harrington Plastics, Harvel Plastics, Swagelock, Cameron Hydraulic Data by Ingersol-Dresser, or Technical Paper 410: Flow of Fluids Through Valves, Fittings, and Pipe by Crane). If tubing is used, the tables in some of these guides may not be applicable, but formulas for calculating pressure drop may be applied.

Since piping friction varies approximately with flow “squared” and inversely with pipe diameter to the 5th power, only a small increase in pipe size will dramatically reduce friction. For example, the data in Table 15 are representative for schedule 80 PVC piping.

Table 15 Flow vs. Velocity and Friction Loss by Pipe Size

Size 20 mm 25 mm 32 mm

I.D. 16 mm 21 mm 27 mm

Flow (lps) Velocity (mps)

Friction Loss (kPa/m)

Velocity (mps)


Velocity (mps)


0.13 0.90 0.79 0.48 0.17 0.29 0.09

0.32 2.25 4.43 1.20 0.95 0.71 0.27

0.44 3.15 8.13 1.67 1.74 1.0 0.49

0.63 2.28 3.31 1.43 0.94

Note: In metric units, “Size” refers to nominal outside diameter; I.D. refers ~ to internal diameter equivalent to nominal English sizes.

Size ½" ¾" 1"

Flow (gpm) Velocity

(fps) Friction Loss

(psi/100 ft) Velocity

(fps) Friction Loss

(psi/100 ft) Velocity

(fps) Friction Loss

(psi/100 ft)

2 2.95 3.48 1.57 0.74 0.94 0.38

5 7.39 19.59 3.92 4.19 2.34 1.19

7 10.34 35.97 5.49 7.69 3.28 2.19

10 7.84 14.65 4.68 4.16

Note: In English units, “Size” refers to nominal dimension.

If guidance is to be developed, it is recommended that it be based on a maximum allowable friction loss per meter or per 100 feet (of “equivalent” length: pipe + fittings converted to equivalent length of pipe) rather than velocity. As Table 15 shows, for a given velocity, the friction loss is greater in smaller pipe diameters. A typical facility system guideline for small hydronic piping has been to limit friction loss to 0.5 kPa/m (2.2 psi per 100 feet). Process cooling systems use a higher limit (~ 0.9 kPa/m or 4 psi/100 feet), possibly because space limitations within equipment require smaller pipe sizes and possibly because these systems have greater available differential pressure. But without studying this situation on a cost:benefit basis, the optimal value for allowable friction loss in equipment piping is still unknown.

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4 USING THE TEE CALCII UTILITY-TO-ENERGY CONVERSION TOOL

4.1 S23 TEE Calculator Overview

The ISMI Total Equivalent Energy Calculator (TEECalc) is a web-based application written in Visual Basic.net/ado.net using an asp.net interface with an SQL Server 2008 database. It is compatible with Internet Explorer 6 or higher, Mozilla Firefox, and Safari web browsers. To protect users’ confidential data, TEE CalcII incorporates a custom web authentication and security system, including SQL injection and session high jacking protection. Session authentication requires users to register their email accounts with the provider to enable the two- step login procedure.

TEE CalcII provides data storage and the ability to share data with other users or keep the data private; graph comparisons between equipment; and calculate total equivalent energy (TEE) by equipment, functional area, or other user-defined fab spaces or variables.

4.1.1 Similarities to TEE CalcI

Peak and Idle flow rates/power and percentage of time at Peak and Idle are entered at the Component level and for each utility.

Processing, idling, and shutdown percentages are entered at the component level as well. If a piece of equipment has multiple components, the percentages can be the same but do not need to be.

In accordance with SEMI S23, the Energy Conversion Factors (ECFs) for chiller-cooled process cooling water is modified by TEE CalcII using the input value of the differential temperature.

Flow rate inputs are required to be in standard units for the SI or IPS system of units; conversion from other units or from “actual” conditions is not supported.

4.1.2 Changes from TEE CalcI

4.1.2.1 Database and Export Features

Can share the database of equipment, components, and ECFs with other users. May select individual users or entire company entities.

Can sub-divide database of equipment and components into categories (e.g., Litho, Etch, Implant, Test, Sub-fab, Support, etc.) rather than having a single folder. Users may define the categories.

Can search for a component or equipment by name, key word, etc.

Can export output data to Excel (as a *.csv file)

4.1.2.2 Calculations and ECFs

Allows the user to decide whether a piece of equipment will be assigned the same process/idle/standby/off percentages for ALL its components or whether the individually assigned percentages for each component will be used for the TEE calculations.

Adds a “standby” state for components (% of year and power/flow during standby)

Uses distinct processing, idle, and standby state power and flow values.

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Calculates custom ECFs, and adds user-defined ECFs. User-defined ECFs can be “above” or “below” the line of total TEE.

Accounts for Fuel and HVAC energy with ECFs. The user can change the values.

Specifies a delta-T (temperature) for chiller PCW at the component level, and allows the PCW ECF to be configured for each component individually rather than at the equipment level.

Calculates the component-weighted average chiller PCW delta-T based on the constituent component delta-T and flow, and uses the resulting value to automatically assign the correct chiller PCW ECF for the TEE and heat burden calculations.

4.1.2.3 Reports

Adds a menu-driven report selection feature (multiple report types)

Sums TEE (energy values) for multiple pieces of equipment by category (i.e., certain equipment, functional area, subfab only, cleanroom only, fab only, and any other user-definable space).

Displays output report and/or graph in a separate browser as a PDF that the user can view, print, or save. The PDF file can be password-protected.

Provides data in columns in a report comparing components and equipment rather than providing separate pages for each component.

4.1.2.4 Graphing

Compares up to 10 pieces of equipment graphically.

Can graph the above summations of TEE (energy values) by categories or by specific utility.

4.2 S23 TEE Calculator Software Requirements and Installation Details

To run TEE CalcII, the following are required:

Internet provider through at least a DSL link

Microsoft Windows XP SP3 or Vista operating system

Internet Explorer 6 or higher, Mozilla Firefox, or Safari web browser

Javascript enabled on user’s computer

An email account that is registered with ISMI/SEMATECH to which the session Access Code will be sent (see Figure 15 and section 4.3).

The S23 TEE Calculator resides on a host server instead of on the user’s computer.

This offers several advantages:

Application updates – When the program is updated by adding a feature or by fixing an error, the change is automatically integrated without having to uninstall/reinstall a program on the user’s computer.

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Data sharing – Users are in control of the data; it may be shared with designated persons or entities. This avoids the need to export the data and sending it by email or in any other physical form (CD, etc.).

Security – Only registered users can access the program; access is terminated as soon as the registered email address is cancelled (user leaves the employer).

Go to http://www.teecalc.com, and click the Request Access button to register for TEE CalcII. Fill in the requested information and click Send button. See Request Access (Figure 15).

Figure 15 Request Access to the TEE Calculator


http://www.teecalc.com/

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4.3 Basic Steps to Use the S23 TEE Calculator

1. Set up a user account with ISMI/SEMATECH

2. Log in and change your password:

a) Log in with your user name and password

b) Retrieve the Access Code (an eight digit number) from your e-mail account inbox)

c) Type or copy/paste the number into the blank space entitled “Access Code” on the log-in screen

d) Click Verify

See the Log-in Screen/Access Code window (Figure 16). The user interface Home Window (Figure 17) will appear on your screen.

Figure 16 Log-in Screen/Access Code Window

3. Use the default SEMI S23 ECF set or define an ECF set

4. Create Components (one or more) in the database

5. Create Equipment (one or more) in the database

6. Decide if any component, equipment, or ECF sets are to be shared with other users (optional)

7. Associate Components with Equipment


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8. Produce a report (TEE Component Comparison, TEE Equipment Comparison, TEE Equipment, TEE Category)

9. View graphs comparing Equipment annual TEE (total equivalent energy) usage

10. Export reports and save as Excel or PDF files (optional)

For detailed information about TEE CalcII functions, see the individual sections pertaining to each function.

4.4 Instructions for Using the S23 TEE Calculator

The S23 TEE Calculator Home Window contains the following seven buttons across the top of the home page (Figure 17):

Home

Equipment

Components

Energy Conversion Factors

Reports

Feedback

Documentation

Figure 17 S23 TEE Calculator Home Window


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4.4.1 S23 TEE Calculator Homepage View

The following activities can be initiated from the S23 TEE Calculator Home Window (Figure 17). For further explanation and details, see the referenced sections:

Equipment button (Section 4.4.2)

– Define a new piece of Equipment

– Establish sharing parameters

– Copy/update/delete existing Equipment

Components button (Section 4.4.3)

– Define a new Component

– Establish sharing parameters

– Copy/update/delete existing Components

Energy Conversion Factor button (Section 4.4.4)

– View the current S23 Energy Conversion Factors

– Create custom ECF sets

– Add user-defined utilities and ECF values

Reports button (Section 4.4.5)

– View several types of reports including a TEE Component Comparison, TEE Equipment Comparison, TEE Equipment, and TEE Category. The most comprehensive report (TEE Equipment) includes both a high level summary and detailed calculations for hourly TEE, annual TEE, associated Heat Burden, and air conditioning load for each component. Calculations are performed and reported for Equipment processing, idle, and standby states. (See Definitions and Part I of Application Guide for further explanation of Heat Burden.)

– View a graphic comparison of annual TEE of user-selected equipment (up to 10 pieces of equipment can be compared) by Equipment name or selected Category.

Send Message to ISMI button (Section 4.4.6)

– Format a message to ISMI to report a problem, ask a question, make a comment, or suggest an improvement to TEE CalcII.

Documentation button (Section 4.4.7)

– Access the User’s Guide to TEE CalcII.

4.4.2 Creating Equipment

To create a new piece of process equipment

1. Click the Equipment button on the Home window; then click the Add New button at the top left corner of the window. Fill in the blanks to define a piece of equipment. See Equipment “Add New” window (Figure 18).

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2. Process, Idle, Standby, Shutdown (Figure 19):

a) The percentages for Process, Idle, Standby, and Other that are assigned in this view must add up to 100%.

b) SEMI S23-0708 recommends that values of 70%, 25%, and 5% be used for Process, Idle, and Shutdown, respectively, but TEE CalcII will use any values assigned in this view. You can also assign a value for a fourth category, Standby, an operating state with a lower utility consumption than Idle. Although a warning will be given in the TEE report if the SEMI S23 recommended values are not used, your input values will still be used for the calculations.

c) The percentage values assigned are used in the TEE calculations only if the user chooses to assign these values to all components belonging to the given piece of equipment. The default calculation will use the component-level percentages that were assigned to each component during component definition. The default provides the greatest accuracy, recognizing that all components associated with a piece of equipment may not be loaded for the same time percentages. Equipment-level percentages are assigned just before outputting a report (see Section 4.4.5 for an illustration).

After the information is filled in, click the Save button.

Figure 18 Equipment “Add New” Window


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Figure 19 Equipment “Add New” Window, Highlighting Process, Idle, Standby, and Shutdown Percentage Fields

3. Assigning Components to Equipment

To create Components, see the instructions in Section 4.4.3. The lower portion of the “Add New” window has two boxes entitled “Available Components” and “Assigned Components.” Once Components have been created, they will appear in the “Available Components” box.

4. Adding a Component to Equipment

To assign a Component to this Equipment, click a Component in the “Available Components” box, then click the “right arrow” between the boxes. The selected Component will appear in the “Assigned Components” box.

5. Removing a Component

To remove a Component from this Equipment, click the Component in the “Assigned Components” box, then click the “left arrow” between the boxes. The selected component will disappear from the “Assigned components” box.

See Figure 20; note the green arrow for Adding/Removing a Component.


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Figure 20 Adding/Removing Components from Equipment and Viewing Components

6. Searching pieces of Equipment in the user database

After one or more pieces of Equipment have been defined, you can view all of the pieces of Equipment by using the Search button. Search options include “name,” “description,” “category,” “key word,” or “all.” Once the search is completed, you an view a piece of equipment from the search by using the View button.

See Figure 21; note the yellow arrow at the “Search” button and the search result using the “All” option.

Figure 21 Searching Equipment Data Base


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7. Deleting a piece of Equipment from the database

Any piece of Equipment named in the equipment window can be deleted from the database by clicking the Delete button to the right of the “Assigned Components” box. Note: you must be the owner of the equipment to be able to delete it. If another user is sharing it with you, you cannot delete that piece of equipment. See the difference between Deleting private Equipment (Figure 22) and Shared equipment cannot be deleted (Figure 23). Shared equipment cannot be updated or deleted by a non-owner.

Figure 22 Deleting Private Equipment (Not Shared)


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8. Copying a piece of Equipment in the user database including Equipment shared by other users

When a piece of Equipment is being “viewed,” click Copy (bottom right corner of screen). The Equipment name will change to “Copy of …..” Then click Save (bottom right corner of screen) to save the equipment to your database. Before saving, you may change the name from “Copy of …” to a unique name.

Figure 23 Shared Equipment Cannot be Deleted or Edited

9. Sharing a piece of Equipment

You can share Equipment, Components, or ECF sets with other users by scrolling down to the “Web Share” line below the Equipment data input area. Using the drop-down menu, select either Private, Share with selected companies, or Share with selected users. You can select one or more companies or one or more users from the list of registered users using the “share with selected users” option and the “lookup menu.” See Equipment Web Share Options (Figure 24). You may also use this area to deselect users that were previously selected for data sharing.

Note: To use shared components, equipment, or ECF sets, you must first copy each of them so that they become in effect the users. If you do not do this, any shared equipment or components will not be included in a subsequent report.


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Figure 24 Equipment Web Share Options, Company Share View

10. Categories tab

The third sub-tab in the Equipment window is the Categories tab, which is used to create or view existing Categories of equipment. The categories can be functional areas, spaces in the fab, or any other user division. Categories are used as a way to sort equipment to prepare a Category report that calculates TEE by the defined category, e.g., Litho, Diffusion, the sub-fab, or the clean support area. You may delete only those categories that you have created (see Figure 25).


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Figure 25 Equipment Window, Categories Tab View

4.4.3 Creating a Component

To create a new component

1. Click the Components button at the Home window. A blank Component window will open. See Figure 26 for an example of a defined Component.

2. Enter the requested information.

a) Fill in Component Name

b) Select the appropriate engineering units for the data being entered from the pull-down box (either SI or IPS units). Note: Express utility data in standard or normal conditions of temperature and pressure. The program cannot correct quantities that are not at standard or normal conditions. No matter what input units are used, the Calculator output will be in SI units in accordance with SEMI S23.

c) Note that percent “Processing,” “Idle,” “Standby,” and “Shutdown” needs to be specified for each component. The values do not need to be the same as other components associated with a piece of equipment. Having different values for each component is an enhancement from the original TEE Calculator. However, SEMI S23-0708 recommends default values of 70% processing, 25% idle, and 5% shutdown. SEMI S23 does not currently address “% Standby” but may in the future.


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Figure 26 Component Window

d) Fill in the utility data table including the following:

Percentage of time (during a process cycle; excludes idle time) at maximum flow

Percentage of time (during a process cycle; excludes idle time) at minimum flow

Maximum flow rate or power consumed (assumed during processing “state”)


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Minimum flow rate or power consumed ( during processing “state”)

Flow rate or power consumed during idle state

Flow rate or power consumed during standby state

Differential temperature (outlet temperature minus inlet temperature) for exhaust, cooling tower cooled (evaporative) process cooling water, and chiller-cooled process cooling water. TEE CalcII will automatically calculate a time (using user-defined process, idle, standby, and off percentages) and flow rate averaged differential temperature that will then used to calculate the ECF value for chiller-cooled process cooling water. The differential temperature values are used for the Heat Burden and HVAC calculations. The HVAC value is the amount of TEE consumed by the air conditioning system to offset the Heat Burden into the space from Equipment.

The above input method (steps 2a–2d) allows each utility for each component to have a different flow/power minimum and maximum during the processing cycle. This capability gives greater accuracy and more flexibility to attaining a valid TEE estimate.

If only the average flow or power during the process cycle is known, you may use it by entering values of

“100” under the “Percent time at Max” column

“0” under the “Percent time at Min”

Average process cycle flow rate or power under the “Flow/power Max” column

This will automatically provide the correct information to the program.

See Figure 27 for a clarification.

e) After all data have been entered, click Update. “Record Update” should appear if the function has been completed correctly. See the Component Data Input window (Figure 28).

Max = 10 scfh

Avg. = 7.5

Min = 5 scfh

50% Max 50% Min

1 process cycle

70% of year 25% of yr

Idle = 4.5 scfh

while processing

Figure 27 Example of Component Input Data


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f) After updating (saving) the component record, you may either create another component or perform another function by clicking another button along the top of the screen.

g) You may also delete, update, or copy components from the component window,. (Figure 28).

The Copy component button lets you copy the component currently in view. TEE CalcII will give the new component the name “Copy of …” You should change this to a unique name and then click Update to save the new component. Note: You must copy components that are being shared by another user before running a report.

Figure 28 Component Data Input Window


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The Delete component button lets you delete the component currently in view if you are the owner of that component. You may not delete shared components (components created by another user).

The Update component button lets you save the component after changes have been made to the data fields.

h) Sharing components in the user database

Components can be shared like Equipment database sharing. See Section 4.4.2, item 9, and Figure 24 for instructions on database sharing.

4.4.4 Energy Conversion Factors

1. ECFs in units of kW-hour/meters3 (also expressed as kilowatts per meters3/hour) were derived from SEMI S23-0708. TEE CalcII uses these default values for the ECFs to convert utility flow rates into total annual kilowatt-hours (kWh/year) on a component and equipment-by-equipment basis. You can define non-standard (non-SEMI S23) ECF sets and apply them in this version of TEE Calc as well, allowing you to perform “what-if” analysis. If a non-SEMI S23 ECF is used, it will be “flagged” in the reports. Click the Select pull-down menu button, and select either the SEMI S23 ECF set or another ECF set. SEMI S23 ECFs are automatically selected for TEE calculations at the component level if no other ECF set is selected.

2. You may also copy an ECF set, modify it, rename it, and save it with a new name.

Figure 29 shows the Energy Conversion Factors window for gaseous fluids and the values used in TEE CalcII.

Figure 29 Energy Conversion Factors Window for Gaseous Fluids


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3. The effect on the ECF value for chiller-cooled Process Cooling Water (PCW) caused by changing the differential temperature between supply and return piping may be seen by inputting that value using the pull-down button. Figure 30 shows the Energy Conversion Factors window for liquid fluids and the values used in TEE CalcII. After changing the ECF, you can save the value by clicking the Save icon that appears in the view. Note that the ECF that appears on this view has no effect on the TEE calculations in any reports; a time and flow rate-averaged ECF for chiller-cooled PCW is calculated internally and given in the reports.

Figure 30 Energy Conversion Factors Window for Liquid Fluids


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4. An HVAC ECF is included to calculate the annual TEE required to offset the Heat Burden from equipment (Heat burden = electric power consumed by tool – heat removed by exhaust and cooling water). The SEMI S23 value of 0.287 kWh per kWh (1 kWh per ton of cooling) of heat burden is the default value. Figure 31 shows the HVAC ECF window.

Figure 31 HVAC ECF Window


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5. You may also add an ECF set by clicking Add New Set. This opens a screen with all of the SEMI S23 utilities. Up to 10 non-SEMI S23 utilities can be added and the utilities designated as either “above” or “below” the line. The TEE from the non-SEMI S23 utilities is either added to the annual TEE total for SEMI S23 utilities or the non-SEMI S23 utilities are kept as a separate sub-total. The designation is made in the Report window. Figure 32 shows the Add New Set window.

Figure 32 Add New ECF Set Window


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6. Adjacent to each ECF is a Microsoft Excel icon to help define ECF values. Click the icon to open a spreadsheet containing the variables that approximately define that ECF. By altering the values of the variables, the value of the ECF will change so that you can easily determine an approximate non-SEMI S23 ECF value. Use engineering judgment in deriving non-SEMI S23 ECF values. Figure 33 shows an example of the Excel ECF Calculator.2

Figure 33 Typical ECF Calculator Window

2 The ECF Calculator was created by Ralph M. Cohen Consultancy.


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7. Custom ECF sets can be shared with other users. Click the Share tab, select the ECF set to share, select the Web share option using the pull-down menu, and select companies or parties with whom the ECF set is to be shared. Then click the Update button. This window may also be used to determine whether an ECF set is being shared with another user.

Figure 34 shows the ECF Share window, identifies the user(s) currently sharing the set, and other users with the same company. To share with another user, type the user name into the box identified with a red arrow.

Figure 34 ECF Share Window

4.4.5 Creating a Report

1. Creating a report is essentially the end result of completing all data input. To view a report, click Reports in the command line of the Home window.

2. Click on the drop-down menu button for five report options:

Compare Equipment Graphically – provides a bar graph of TEE for each utility for one piece of equipment

Equipment TEE Report – provides the most detailed summary in tabular form of the TEE for one piece of equipment broken out by component, considering the equipment operating state. Summarizes computations.


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Component Comparison Report – provides a detailed comparison of TEE for components by utility

Equipment Comparison Report – provides a summary- level comparison of TEE for equipment by utility

Equipment Category Report – provides a summary-level rollup of equipment placed in user-defined categories, e.g. Litho, sub-fab, wet bench, nitrogen, etc.

Note: for all reports except the Compare Equipment Graphically report, clicking the box Add custom utility TEE to S23 Utilities Equipment Totals will add the TEE resulting from any non-S23 utilities that were added through the Component input sheet and special ECF set definition to the total TEE; the default (not clicking the box) provides a separate sub-total.

Figure 35 shows the Report window and drop-down menu report choices.

Figure 35 Report Type Selection

3. Detailed instructions for each report type

Compare Equipment Graphically

– Click option. A menu of available equipment appears.

– Highlight a piece of equipment, then click the right arrow to move it to “Equipment to Compare” box (right arrow circled in Figure 36).

– Select up to 10 pieces of equipment to compare; equipment may be selected by name or category.

– After selections are made, click the Compare Equipment button at bottom of window. A bar graph will open in a new window. The graph may be exported to a PDF file (see Figure 37).

– Close the Graph window but clicking the “back” arrow in your browser.


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Figure 36 Compare Equipment Graphically Window

Equipment

Power Supply

Ralph Test 0803

Ralph Test 0910

Ralph Test 728

Shared Equipment

Spreadsheet Tester

Training Demo Equipment

Equipment Comparison GraphExport to PDF

Figure 37 Equipment Comparison Graph and PDF Export Function


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Equipment TEE Report

– Click option. A menu of available equipment will appear.

– Highlight a piece of equipment, then click the right arrow to move it to “Equipment to the Compare box (right arrow circled in Figure 38).

– Select up to 10 pieces of equipment.

Note: Before generating the report, decide whether you want to perform the calculations using the component-defined Process/Idle/Standby percentages (default method) OR using the equipment-defined Process/Idle/Standby percentages. Clicking the box Use Equipment Percentages will override the component percentages in the calculations. When component percentages are used, equipment percentages at the top right corner of the report appear as “N/A.” If non-SEMI S23 recommended equipment percentages are used, a note will appear.

Figure 38 Equipment TEE Report Window


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– After selections are made, click the Generate TEE Report button at the bottom of the window to calculate the added values. Available reports will be shown under the heading “Generated Reports.” View the reports by clicking the equipment name. Only one report can be viewed, but you can scroll through all of the generated reports using the forward and back arrows at the top left corner of the window. You can export reports in a PDF file (see Figure 39) that is either open or password-protected or in an Excel file. These files can be renamed and saved to your computer.

– Close the Equipment TEE Report window by clicking the red close window (red “X”) button in the upper right corner. Be sure to close the report window and not the TEE CalcII window.

Figure 39 TEE Equipment Report Export Options


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– Table 16 shows the information provided a TEE Report and its layout.

Table 16 Information Provided in TEE Report

User supplied equipment information Process/Idle/Standby percentages

S23 equipment annual TEE totals by utility

Non-S23 equipment annual TEE totals by utility

Annual heat burden summary Idle and Idle+Standby:Process ratios

Detailed S23 component data calculations (hourly and annual TEE)

Detailed non-S23 utility component data calculations

TEE totals by component

Component Process/Idle/Standby percentage and annual hours

Data used for heat burden calculation

ECFs for S23 utilities

ECFs for user-defined (non-S23) utilities

Component Comparison Report

– The format and features of this report are similar to the TEE Equipment Report but it allows you to compare different components to assess their TEE consumption. Unlike the equipment report, TEE is not summed except by component.

– You can select components for the report and export the reports just as the TEE Equipment Report.

– To close the report, use the arrows in the upper left corner of the window.

Figure 40 shows the Component Comparison Report component selection window. Figure 41 shows an example of a Component Comparison Report (partial).

Figure 40 Component Comparison Component Selection Window


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Figure 41 Example of a Component Comparison Report


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Equipment Comparison Report

– The format and features of this report are similar to the TEE Equipment Report but it allows you to compare different pieces of equipment to assess their TEE consumption. Unlike the TEE Equipment report, TEE is not shown for individual components.

– You can select components for the report and export the reports just as the TEE Equipment Report.

– To close the report, use the arrows in the upper left corner of the window.

Figure 42 shows the Equipment Comparison Report equipment selection window.

Figure 42 Equipment Comparison Report Equipment Selection Window

Equipment Category Report

– The format and features of this report are designed to give you the TEE of all pieces of equipment in the designated category.

– The report includes the TEE total for the category. Categories can include all equipment in a processing area (e.g., Litho, Diffusion, Etch, etc.), a physical space (e.g., fab, sub-fab, support, etc.), or all equipment using a particular utility. You have some flexibility in defining category reports, with category and sub-category labeling available. The report will be based on meeting ALL of the sort category criteria, not ANY of the sort category criteria.

– Figure 43 shows the Equipment Category Report category selection window.


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Figure 43 Equipment Category Report Category Selection Window

4.4.6 Providing feedback

1. Click the Feedback button in the Home row at the top of the window. Figure 30 shows the Feedback window. A pull-down menu gives several options for selecting the message type:

General Question

Reporting a problem

Suggesting an improvement

Submitting a comment

2. Fill in the subject and add your comments. When ready, click Send.


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Figure 44 Feedback Window

4.4.7 Documentation

1. Click the Documentation button in the Home row at the top of the window to access a current copy of this user’s manual.

4.5 Revision Control

Whenever TEE Calc has been updated, the change is automatically integrated into program the next time you run it. The current version reference is always shown in the log-in area after logging in (e.g., TEE CalcII V0.0912).

4.6 Flow Diagrams

See Figure 45–Figure 47 for flow diagrams showing TEE Calc use and features.

Create User Account

Fill in requested information

Receive user name and password from administrator

Log in and use calculator

Figure 45 Creating a User Account


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Create Component(s)

Fill in required fields for flow/power, min/max %'s,

delta T's, etc.

Save data

Go to other operations

Create Equipment

Fill in required fields for process/idle/standby/off %

and other descriptive information

Assign components

Select ECF set, add utilities

Save data

Go to other operations`

Figure 46 Creating Components and Equipment Flow Diagram

Select Report Type

"TEE Report"

Select Equipment

Click/skip Use Equipment

Percentages and/or Add Custom

Utility TEE to Total

"Compare Equipment

Graphically"

Select up to 10 pieces of equipment

Click Compare Equipment, view/

print graph

Export to PDF

"Component Comparison"

Select components

Click Compare Components, view/

print report

Export to PDF or Excel file

"Equipment Comparison"

Select equipment

Click Compare Equipment, view/

print report


"Equipment Category"

Select category

View/print report


Return to Reports or other operations

View/print Report


Figure 47 Creating Reports Flow Diagram


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5 REFERENCES

[1] SEMI S23 0708, Guide for Conservation of Energy, Utilities, and Materials Used by Semiconductor Manufacturing Equipment, May 13, 2008

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Appendix A – Sample TEE Equipment Report


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International SEMATECH Manufacturing Initiative Technology Transfer

2706 Montopolis Drive Austin, TX 78741

http://ismi.sematech.org e-mail: [email protected]

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