wj deposition overview

WJ APCVD Overview

Steve AngererSteve Angerer

08/28/0208/28/02

WJ APCVD Overview

Objective: Objective:

To get a better understanding of the To get a better understanding of the WJ APCVD systems process, qual WJ APCVD systems process, qual requirements, recognize the tool, and the requirements, recognize the tool, and the failure mechanisms to common problems. failure mechanisms to common problems.

WJ APCVD Definition Terms APCVDAPCVD Atmospheric pressure chemical vapor deposition was the first form of CVD to be widely Atmospheric pressure chemical vapor deposition was the first form of CVD to be widely

accepted in the manufacturing area. The advantage of APCVD is high throughput. One accepted in the manufacturing area. The advantage of APCVD is high throughput. One drawback is that it is prone to generating particles in and on the films.drawback is that it is prone to generating particles in and on the films.

Butterfly ValveButterfly Valve The shape of a damper that controls flow within the tube, line or plenum. The chamber The shape of a damper that controls flow within the tube, line or plenum. The chamber

exhaust pressure is controlled by the PEV (a butterfly-shaped choke valve), and the entry exhaust pressure is controlled by the PEV (a butterfly-shaped choke valve), and the entry and exit exhaust pressures are controlled by manual butterfly-shaped valves.and exit exhaust pressures are controlled by manual butterfly-shaped valves.

Bypass PlenumsBypass Plenums Plenums around the deposition chambers, from one end of the process muffle to the Plenums around the deposition chambers, from one end of the process muffle to the

other, that equalize muffle pressures without causing disruptive flows through the other, that equalize muffle pressures without causing disruptive flows through the deposition chambers. The WJ1000 has two bypass plenums: the muffle bypass and the deposition chambers. The WJ1000 has two bypass plenums: the muffle bypass and the chamber bypass. chamber bypass.

Chamber N2Chamber N2 Chamber nitrogen flows between the outside of the IVA and the inside wall of the Chamber nitrogen flows between the outside of the IVA and the inside wall of the

opening in the process muffle. The flowmeters are numbered to correspond to the opening in the process muffle. The flowmeters are numbered to correspond to the individual deposition chamber. (Also called chamber purge N2) individual deposition chamber. (Also called chamber purge N2)

WJ APCVD Definition Terms

Compact Exhaust Flow Control “CFC”Compact Exhaust Flow Control “CFC” A process exhaust system which controls process exhaust flow independently of the A process exhaust system which controls process exhaust flow independently of the

powder accumulated in the process exhaust hardware. The constant exhaust mass flow powder accumulated in the process exhaust hardware. The constant exhaust mass flow rate prolongs the life of the IVA’s and maintains wafer to wafer film thickness over rate prolongs the life of the IVA’s and maintains wafer to wafer film thickness over longer intervals than the standard system longer intervals than the standard system

Cooling MuffleCooling Muffle Is part of the muffle adjacent to the process muffle at the reactor unload end. The Is part of the muffle adjacent to the process muffle at the reactor unload end. The

cooling muffle removes heat from the wafers and the belt as they pass through it.cooling muffle removes heat from the wafers and the belt as they pass through it.

Curtain N2 Curtain N2 Curtain nitrogen flows are a barrier between the room environment and the process Curtain nitrogen flows are a barrier between the room environment and the process

muffle or etch muffle. There are curtains at the entry and exit of the muffle and before muffle or etch muffle. There are curtains at the entry and exit of the muffle and before and after each deposition chamber. They are usually named for their location within the and after each deposition chamber. They are usually named for their location within the muffle. muffle.

WJ APCVD Definition Terms Deposition ChamberDeposition Chamber

1) The space within the process muffle where deposition occurs. There are four 1) The space within the process muffle where deposition occurs. There are four deposition chambers, bounded by the muffle floor on the bottom, the injector on the top, deposition chambers, bounded by the muffle floor on the bottom, the injector on the top, and the muffle and baffles on both sides.and the muffle and baffles on both sides.

2) One of four openings into the process muffle into which an injector vent assembly is 2) One of four openings into the process muffle into which an injector vent assembly is placed.placed.

3) A term used inaccurately to refer to the IVA, the process muffle, and the load and 3) A term used inaccurately to refer to the IVA, the process muffle, and the load and unload baffle on both sides of a chamber.unload baffle on both sides of a chamber.

Double ContainmentDouble Containment Any two-level safe containment system for hazardous substances. Includes a secondary Any two-level safe containment system for hazardous substances. Includes a secondary

container to prevent escape of material in case the primary container fail.container to prevent escape of material in case the primary container fail.

Etch MuffleEtch Muffle A single-unit enclosure that contains the HF vapor used to clean film deposits from the A single-unit enclosure that contains the HF vapor used to clean film deposits from the

convey belt. The etch muffle has two removable HF plenums, N2curtains, a strip heater, convey belt. The etch muffle has two removable HF plenums, N2curtains, a strip heater, and four exhaust ports.and four exhaust ports.

Etch muffle exhaustEtch muffle exhaust Any of four ports that remove gaseous by-products of HF+SiO2 reaction from the etch Any of four ports that remove gaseous by-products of HF+SiO2 reaction from the etch

muffle. The exhausted areas are connected by flexible tubing, through restricting muffle. The exhausted areas are connected by flexible tubing, through restricting orifices, to the etch muffle exhaust manifold and plenum.orifices, to the etch muffle exhaust manifold and plenum.

WJ APCVD Definition Terms Gas Phase ReactionGas Phase Reaction Chemical Reaction between the deposition gasses in the space above the wafer’s surface. Chemical Reaction between the deposition gasses in the space above the wafer’s surface.

Defects caused by gas phase reactions may include a hazy coating on the wafer, high Defects caused by gas phase reactions may include a hazy coating on the wafer, high particle counts, or thin coatings on all or part of the wafer.particle counts, or thin coatings on all or part of the wafer.

HazeHaze A measure of light scattering, defined as the ratio of scattered light to incident light. WJ A measure of light scattering, defined as the ratio of scattered light to incident light. WJ

uses the term to mean the scattering of light off the surface film on a wafer; the degree to uses the term to mean the scattering of light off the surface film on a wafer; the degree to which a film on a wafer looks cloudy. which a film on a wafer looks cloudy.

Injector Injector A component that distributes gas mixture. The injector receives gas mixtures from the A component that distributes gas mixture. The injector receives gas mixtures from the gas cabinet and distributes them as laminar flows into the deposition chamber, across the gas cabinet and distributes them as laminar flows into the deposition chamber, across the width of the conveyor belt. ( Injector Vent Assembly (IVA), Monoblok injector)width of the conveyor belt. ( Injector Vent Assembly (IVA), Monoblok injector)

Injector Vent AssemblyInjector Vent Assembly Laminar FlowLaminar Flow Movement of air or gas, in which the entire body of air or gas essentially moves as a Movement of air or gas, in which the entire body of air or gas essentially moves as a

sheet, with uniform velocity, along parallel lines. The narrow slots between the skirts of sheet, with uniform velocity, along parallel lines. The narrow slots between the skirts of the injector create laminar flows of gas, which continue to the wafer surface, where the injector create laminar flows of gas, which continue to the wafer surface, where reaction occurs. reaction occurs.

WJ APCVD Definition Terms Load GapLoad Gap The distance between wafers on the conveyor belt. Load Gap is measured in inches from The distance between wafers on the conveyor belt. Load Gap is measured in inches from

trailing edge of one wafer to the leading edge of th e next wafer. This is a major player trailing edge of one wafer to the leading edge of th e next wafer. This is a major player for wafer uniformity.for wafer uniformity.

Metering TubeMetering Tube The tube within the shield that distributes nitrogen inside the frames. Four metering The tube within the shield that distributes nitrogen inside the frames. Four metering

tubes are installed in the shield plates; N2 supplied by the end plate through the tubes tubes are installed in the shield plates; N2 supplied by the end plate through the tubes and is uniformly distributed within the plenum. and is uniformly distributed within the plenum.

MuffleMuffle An enclosed space within which a process or other chemical or thermal activity occurs.An enclosed space within which a process or other chemical or thermal activity occurs.

PlenumPlenum A space or enclosure in which a gas is at greater-than-atmospheric pressure. There are A space or enclosure in which a gas is at greater-than-atmospheric pressure. There are

two plenums on each of three plates in a parallel injector, which distribute gases evenly two plenums on each of three plates in a parallel injector, which distribute gases evenly to the metering slots.to the metering slots.

PowderPowder A process anomaly in which particles accumulate on a wafer surface due to a gas phase A process anomaly in which particles accumulate on a wafer surface due to a gas phase

reaction. Powder particles are usually 1-10 microns in diameter, and are visible to the reaction. Powder particles are usually 1-10 microns in diameter, and are visible to the eye. Powder collects in the system’s vent and exhaust elbows.eye. Powder collects in the system’s vent and exhaust elbows.

WJ APCVD Definition Terms Process MuffleProcess Muffle The enclosure within which deposition occurs. The process muffle is a long, flat tube. The enclosure within which deposition occurs. The process muffle is a long, flat tube.

Open at both ends to allow the conveyor belt to transport wafers through the deposition Open at both ends to allow the conveyor belt to transport wafers through the deposition environment. The muffle has openings at the top for IVAs.environment. The muffle has openings at the top for IVAs.

SkirtsSkirts The thin metal strips welded to the center and bottom plates of a parallel-plate injector. The thin metal strips welded to the center and bottom plates of a parallel-plate injector.

The skirts create laminar flows of reactants and N2. The skirts create laminar flows of reactants and N2.

Step CoverageStep Coverage A measure of film quality that describes the evenness of deposition over a step-shaped A measure of film quality that describes the evenness of deposition over a step-shaped

structure. Step coverage is evaluated by comparing film thickness on the top of a step structure. Step coverage is evaluated by comparing film thickness on the top of a step with that on the bottom of the step, or by comparing thickness on the side of the step with that on the bottom of the step, or by comparing thickness on the side of the step with that on the bottom of the step.with that on the bottom of the step.

Throttle ValveThrottle Valve

Toroidal OrificeToroidal Orifice

WJ APCVD Process Overview

The Basic Task is to lay down a thin film of SiO2 The Basic Task is to lay down a thin film of SiO2 on the component side of 8” diameter wafers. on the component side of 8” diameter wafers.

This is done in a heated, atmospheric pressure This is done in a heated, atmospheric pressure environment isolated by exhaust ports, N2 curtain, environment isolated by exhaust ports, N2 curtain, and mechanical baffles.and mechanical baffles.

The process muffle receives a single row of 200 The process muffle receives a single row of 200 mm wafers moving along a continuous conveyor mm wafers moving along a continuous conveyor belt. belt.

WJ APCVD Process Overview cont.

The wafers are isolated from outside influences, The wafers are isolated from outside influences, pre-heated, and passed through each process pre-heated, and passed through each process chamber in sequence.chamber in sequence.

Each wafer receives process vapors from reactor Each wafer receives process vapors from reactor components located outside the muffle area.components located outside the muffle area.

Liquid source chemicals flow through coaxial Liquid source chemicals flow through coaxial lines to the reactor. In the reactor, chemicals are lines to the reactor. In the reactor, chemicals are vaporized, diluted with N2, mixed together and vaporized, diluted with N2, mixed together and passed through heated lines to the reactor gas passed through heated lines to the reactor gas cabinet, then to the injector bay where the gasses cabinet, then to the injector bay where the gasses are deposited on the wafers.are deposited on the wafers.


The wafers are moving continuously on the The wafers are moving continuously on the conveyor belt, which also receives a thin film conveyor belt, which also receives a thin film during APCVD deposition. To remove this film, during APCVD deposition. To remove this film, the belt is exposed continuously to acid vapors, DI the belt is exposed continuously to acid vapors, DI water sonic agitation , air spray, and heat to water sonic agitation , air spray, and heat to remove process contaminants.remove process contaminants.

In our application for best uniformity and step In our application for best uniformity and step coverage the wafers receive 2 passes through the coverage the wafers receive 2 passes through the entire process.entire process.


The film deposited must comply with certain The film deposited must comply with certain physical and chemical requirements in order to physical and chemical requirements in order to be used in device fabrication:be used in device fabrication:

1.1. Uniformity of the layer.Uniformity of the layer.

2.2. Density of SiO2 molecules in the layer.Density of SiO2 molecules in the layer.

3.3. Amount and type of stress. Amount and type of stress.

4.4. Thickness of the layer.Thickness of the layer.

5.5. Surface smoothness of the layer.Surface smoothness of the layer.

6.6. Freedom of the layer from particlesFreedom of the layer from particles

7.7. Chemical purityChemical purity

8.8. Step coverage or ability of the layer to fill in gaps or trenches Step coverage or ability of the layer to fill in gaps or trenches beneath the layer.beneath the layer.

WJ APCVD Qualification Requirements

Equipment Start up QualificationEquipment Start up Qualification 1. Backside PC: 20000 1. Backside PC: 20000

2. Stress : < 300MPa 2. Stress : < 300MPa

3. R.I : 1.44-1.46 3. R.I : 1.44-1.46

4. Shrinkage : <9% (1000 C, 30 MIN) 4. Shrinkage : <9% (1000 C, 30 MIN)

5. Stability : <1% thickness change/24 hours 5. Stability : <1% thickness change/24 hours

6. Etch rate : 38-50 A/min(30 min in 0.49% HF) 6. Etch rate : 38-50 A/min(30 min in 0.49% HF)

7. Step coverage: 100 % covered 7. Step coverage: 100 % covered

8. Metal concentration (front side): 10 * 8. Metal concentration (front side): 10 *

9. Metal concentration (back side): 300 * 9. Metal concentration (back side): 300 *

* In unit of E10/cm2 for Cr+Fe+Ni+Cu+Zn * In unit of E10/cm2 for Cr+Fe+Ni+Cu+Zn

WJ APCVD Qualification Requirements cont.

Pre Lot Process Qual:Pre Lot Process Qual: Spec Test Control Spec Test Control

Process Parameter Target Freq Chart Process Parameter Target Freq Chart

------------------------------- --------- ---------- ---------------------- ------------------------------- --------- ---------- ----------------------

STI NSG Qual Thk (Ang) (M) 48,PM1 DQ-THSTI7K STI NSG Qual Thk (Ang) (M) 48,PM1 DQ-THSTI7K ( 7700A Target )( 7700A Target )

STI NSG Qual Thk Range <1362 48,PM1 DQ-THSTI7K STI NSG Qual Thk Range <1362 48,PM1 DQ-THSTI7K ( 582A Target )( 582A Target )

(Thk 1 SIGMA) 330 (Thk 1 SIGMA) 330

STI Qual Dep PC's 20 48,PM1 DQ-PCSTI7K STI Qual Dep PC's 20 48,PM1 DQ-PCSTI7K ( > 10 OOC )( > 10 OOC )

Thickness is Controlled by Process WorksThickness is Controlled by Process Works

Tuning Qual then the actual thickness qual. Process Works makes an Tuning Qual then the actual thickness qual. Process Works makes an adjustment to the belt speed to center in thickness target. adjustment to the belt speed to center in thickness target.

WJ APCVD Qualification Requirements cont.

Lot / Process Control:Lot / Process Control: Spec Test Control Spec Test Control

Process Parameter Target Freq Chart Process Parameter Target Freq Chart

------------------------------- --------- ------- ----------------- ------------------------------- --------- ------- -----------------

STI NSG Thk (Ang) (M) L TM-TH-STI STI NSG Thk (Ang) (M) L TM-TH-STI ( 7700A Pilot )( 7700A Pilot )

Monitored L TM -TH-STIP ( 7450A Prod ) Monitored L TM -TH-STIP ( 7450A Prod )

STI NSG Thk Range <1362 L TM-TH-STI STI NSG Thk Range <1362 L TM-TH-STI ( 582A Pilot )( 582A Pilot )

(Thk 1 SIGMA) 330 (Thk 1 SIGMA) 330

NSG Dep. PC's 25 L DM-PC-STI NSG Dep. PC's 25 L DM-PC-STI ( > 10 OOC )( > 10 OOC )

Process Works Re-Tunes after every 4Process Works Re-Tunes after every 4thth lot to lot to re-center thickness. re-center thickness. ( Only if the tool is idle )( Only if the tool is idle )

WJ APCVD Return Side

WJ APCVD Facilities Side

WJ APCVD Wafer Path

WJ APCVD System Layout

LoadUnload

WJ APCVD Injector Layout

WJ APCVD Problems Particles:Particles: 1.1. Exhaust too Low or unbalancedExhaust too Low or unbalanced

2. Exhaust butterfly valve (MKS) >75 degrees2. Exhaust butterfly valve (MKS) >75 degrees

3. Separator port too low3. Separator port too low

4. Injector temperature too low4. Injector temperature too low

5. Time for injector change (nitrogen shield 5. Time for injector change (nitrogen shield cleaning)cleaning)

6. Deposition temperature too low6. Deposition temperature too low

7. Chemical or O3 concentration too high7. Chemical or O3 concentration too high

8. Teos bubbler temperature too low8. Teos bubbler temperature too low

9. Poor belt cleaning9. Poor belt cleaning

a. Ultrasonic belt cleaner needs flushinga. Ultrasonic belt cleaner needs flushing

b. HF bubbler level too lowb. HF bubbler level too low

10. Toridal orifice failure 10. Toridal orifice failure

11. Incorrect gas sequence11. Incorrect gas sequence

12. Water Leak in injector base plate12. Water Leak in injector base plate

13. Wafer Cleanliness13. Wafer Cleanliness

14. Calibration of particle analyzer14. Calibration of particle analyzer

15. Fab humidity15. Fab humidity

Film InstabilityFilm Instability

1. Deposition Rate too high1. Deposition Rate too high

2. O3 concentration too low2. O3 concentration too low

3. Film too thick3. Film too thick


5 Teos bubbler temperature too low5 Teos bubbler temperature too low

6. High Humidity6. High Humidity

Poor Crack ResistancePoor Crack Resistance



3. Film too thick3. Film too thick


WJ APCVD Problems cont.

Poor UniformityPoor Uniformity

1. Poor temperature profile1. Poor temperature profile

2. Damaged belt2. Damaged belt

3. Poor gas flow distribution3. Poor gas flow distribution

a. Incorrect chamber exhaust settingsa. Incorrect chamber exhaust settings

b. Separator too lowb. Separator too low

c. Outer port flow too highc. Outer port flow too high

d. Mismatched N2 curtain / shield flowd. Mismatched N2 curtain / shield flow

4. Wafer cleanliness4. Wafer cleanliness

5. Wafer load gap too large5. Wafer load gap too large

6. Dirty or misaligned injector6. Dirty or misaligned injector


8. Bent or damaged injector plate or shield8. Bent or damaged injector plate or shield

9. Glass build up on muffle floor9. Glass build up on muffle floor

10. Muffle not level10. Muffle not level

High Etch RateHigh Etch Rate




4. Contaminated Teos4. Contaminated Teos

High StressHigh Stress




WJ APCVD Problems cont. Poor Step CoveragePoor Step Coverage


2. Wrong deposition sequence2. Wrong deposition sequence

3. Unintended doping of SiO2 film3. Unintended doping of SiO2 film

4. Surface cleanliness4. Surface cleanliness

5. Surface sensitivity5. Surface sensitivity

Thickness Variation Thickness Variation Chamber to ChamberChamber to Chamber

1. Bubbler temperature inconsistent1. Bubbler temperature inconsistent

2. Temperature profile variations2. Temperature profile variations

3. Gas flow variations3. Gas flow variations

4. O3 delivery inconsistent4. O3 delivery inconsistent

5. Injector damaged5. Injector damaged

6. Unintended doping of film6. Unintended doping of film

High ShrinkageHigh Shrinkage




4. Separator flow too high (for SiO2 at <415 C)4. Separator flow too high (for SiO2 at <415 C)

Low Deposition RateLow Deposition Rate

1. Deposition temperature too high1. Deposition temperature too high

2. Chemical flow too low2. Chemical flow too low

3. Bubbler temperature too low3. Bubbler temperature too low


5. Injector port or shield flows low5. Injector port or shield flows low

6. O3 concentration too high6. O3 concentration too high

7. Line heater temperature too low7. Line heater temperature too low

8. Lack of adequate delivery line insulation8. Lack of adequate delivery line insulation

9. Teos contamination9. Teos contamination

10. N2 facilities pressure low10. N2 facilities pressure low

WJ APCVD Problems cont.

Surface SensitivitySurface Sensitivity 1. Deposition temperature too low1. Deposition temperature too low 2. O3 concentration too low2. O3 concentration too low 3. Surface cleanliness3. Surface cleanliness 4. Hydrophilic substrate material4. Hydrophilic substrate material

Fine Line StripingFine Line Striping

1. Inner port flow too high1. Inner port flow too high 2. Separator port flow too high2. Separator port flow too high 3. Contamination in the slotted skirt3. Contamination in the slotted skirt

Poor Injector LongevityPoor Injector Longevity

1. Chamber exhaust setting too low1. Chamber exhaust setting too low

2. Facilities exhaust to low so exhaust butterfly 2. Facilities exhaust to low so exhaust butterfly (MKS) valve is >75 degrees open(MKS) valve is >75 degrees open

3. Chemical flow too high3. Chemical flow too high

4. Injector / vent shield flows too low4. Injector / vent shield flows too low


6. Bent or damaged injector plate or shield6. Bent or damaged injector plate or shield

7. Glass build up on muffle floor7. Glass build up on muffle floor

wj deposition overview

Technology

process muffle

process exhaust flow

process exhaust hardware

chamber exhaust pressure

muffle bypass

chamber bypass

thea process exhaust

muffle pressures