Reclaim, Recycle, & Reuse of Oxide Slurry for the CMP Process By Daniel S. Kettler, Director of Sales, Service, & Marketing Faeth Asia Pacific Sdn. Bhd., a member of The FäthGroup

„Since the mid-90’s, Oxide Slurry polishing has remained a critical step in the CMP Process for semiconductor manufacturing.

„Most fabs use an “off the shelf” Oxide Slurry product produced by a few global manufacturers and shipped to their facility in 200 liter drums or 1000 liter IBC’s.

„The raw slurry is then diluted with UPW prior to use at the polishers.

„The FÄTHGROUP has developed a unique, patented system for the on-site reclaim, recycle, and reuse of Oxide Slurry.

„The system was developed in Europe over a nine year period from 2000-2009.

„Beta system “on-wafer” testing completed with partner fab in Germany 2009-2010.

„US Patent received 2012

„The system is currently qualified and in-use for production at fabs in:

–Germany (1) 2010

–France (1) 2011

–USA (2) 2010-1012

–Japan (1) 2012

–Malaysia (1) 2012

„Installation in progress at 2 fabs in Singapore.

„A reuse rate of 80-85% for slurry and water is typical.

WHY

RECYCLE

OXIDE

SLURRY?

„A high production semiconductor manufacturing fab will consume over 1,500,000 liters yearly of mixed Oxide Slurry for the CMP Process.

„Combined with the ultra-pure water used at the polishers, this can generate over 100,000,000 liters of oxide slurry wastewater yearly that must be treated and disposed.

Why Recycle Oxide Slurry?

No Effect To Process Quality

Economic Benefits

Reduced Environmental

Impact

FAETH SYSTEM

PROVIDES…

Reduced Environmental Impact

„Government & Community Acceptance –“Part of the Solution”

–“Good Neighbor”

„Future Growth –Meet Tightened Emission Regulations

–Site Expansion

–New Site Construction

„Employee Health, Wellness, and Satisfaction

„Financial - Savings

–Reduced waste disposal fees

–Reduced WWT costs

–Potential subsidies from government agencies

„University Cooperation

–R & D funding

–Co-op Employment

–Recruitment Opportunities

No Effect to Process Quality

Fresh Slurry

Recycled

Number of Polished Wafers on Single Pad

Removal Rate vs. Slurry Source

440

450

460

470

480

490

500

510

520

530

540

Rem

ova

l R

ate

(n

m/ 2

min

)

0 500 1000 1500 2000 2500

Removal Rate Consistency

pH Level – Monitoring and Control

[p

H]

pH by Slurry Batch

0

2

4

6

8

10

12

recycle

d

recycle

d

recycle

d

recycle

d

Ch

arg

e 2

Ch

arg

e 3

Ch

arg

e 4

Ch

arg

e 5

Ch

arg

e 6

Ch

arg

e 7

Ch

arg

e 6

Ch

arg

e 7

Ch

arg

e 7

Ch

arg

e 8

Ch

arg

e 9

Ch

arg

e 1

2

Ch

arg

e 1

3

Ch

arg

e 1

4

Ch

arg

e 1

5

Ch

arg

e 1

6

Ch

arg

e 1

7

Ch

arg

e 1

8

Ch

arg

e 1

8

ad

ders

> 0

.27µ

Scratches QC vs. Slurry Condition

0

10

20

30

40

50

60

70

80

02.0

9.2

009

09.0

9.2

009

16.0

9.2

009

23.0

9.2

009

30.0

9.2

009

07.1

0.2

009

14.1

0.2

009

21.1

0.2

009

Recycled Recycled Fresh Slurry Fresh Slurry

Uniformity and Defectivity

Real-time Slurry Analysis and Data Logging

„Percent Solids

„pH

„Density

„Time/Date stamp of batch production

„Historical trend analysis capabilities

„Complete chemical analysis w/ optional package

Closed Loop Control: Density

Closed Loop Control: pH

Closed Loop Control: Density vs. pH

Economic Benefits

„ 80-85% Reduction in fresh slurry usage

–Significant reduction in raw slurry consumption

–Significant reduction in DI water used for slurry dilution

„ 80-85% Recovery of DI water.

–Recovered DI water can be re-used at the polisher (e.g. for flushing)

–Recovered DI water can be easily treated and used in less critical processes such as rinses or cooling towers.

„Additional Savings

–Reduced chemical consumption for WWT

–Reduced solid waste disposal fees

„Short ROI Timeframe

–Typically less than 16 months, depending on existing facilities available.

–Slurry recycling systems available in various sizes for evaluation/lease period

Oxide Slurry Recycling System

Description

Flow Diagram: CMP Slurry Recylcing

CONSUMER/

RE-CLAIM

UF

Recir-

cula

tion

Perm

eat

M

N2

stainless steel ¼‘‘

Sta

biliz

ier

PFA ¾‘‘

SUPPLY-

PUMP Resin-

Filter

CMP-

PreFilter

10 µm

PFA ½‘‘

Concentrate to

B150

Recycling-Tank

PFA ½‘‘

PERMEAT-

PUMP

RECIRCULATION-PUMP

CMP-Filter-

1

CMP-

Filter-2

PF

A ½

‘‘

Sta

biliz

ier

M

PC

N1

FISA

UF

F1

N2

LISA

N3

TMP

UF

LISA

N4

FIOA

PCRN

LISA

PERM

LISA

RECI

LISA

BUFF

PISA

UF CONC

UF

Flow Diagram: Filtration Phase

M

N2

stainless steel ¼‘‘

Sta

biliz

ier

PFA ¾‘‘

SUPPLY-

PUMP Resin-

Filter

CMP-

PreFilter

10 µm

PFA ½‘‘

Concentrate to

B150

Recycling-

Tank

PFA ½‘‘

PERMEAT-

PUMP

RECIRCULATION-PUMP

CMP-Filter-

1

CMP-

Filter-2

PF

A ½

‘‘

Sta

biliz

ier

M

PC

N1

FISA

UF

F1

N2

LISA

N3

TMP

UF

LISA

N4

FIOA

PCRN

LISA

PERM

CONSUMER/

RE-CLAIM

LISA

RECI

LISA

BUFF

PISA

UF

CONC

UF

UF

Recir-

cula

tion

Perm

eat

Waste Collection and Pre-filtering

• Oxide Slurry wastewater from all polishers continuously

drained into large collection tank.

• From there it is pumped through pre-filters to remove

agglomerates and other waste materials.

Particle and Water Separation

• Pre-filtered wastewater continuously recirculated through

Ultra-filter membranes to separate silica particles from

water.

• Some water returned to Recirculation tank for slurry re-

condensing.

• Excess water sent to Permeate tank for re-use.

PermeateTank

Pump

RecirculationTank

Ultra-Filter Membrane

Par

ticl

e Se

par

atio

n

Water

Water

Particle Retrieval via Patented UF Backwash

• Patented backwash procedure retrieves silica particles

from UF Membrane and sends then to Recirculation Tank

for slurry re-condensing.

• Backwash procedure also ensures membrane “health” to

extend use typically beyond 12 months.

Batch Qualification and Transfer

• On-line instrumentation monitors pH, % solids, and

density to achieve specified recipe.

• KOH or NH4OH added to refresh the pH.

• Once qualified, recycled slurry is pumped through final

filters during transfer to Mix Tank.

Recycled Slurry Prepared for Re-use

• Calculated volume of fresh slurry added to recycled

slurry batch in Mix tank.

• After mixing, sample can be analyzed off-line to qualify

batch for pH, % solids, density, & metal ions.

• Once qualified, mixed slurry transferred to Storage Tank.

Recycled Slurry Transferred to Oxide Slurry Distribution System

• Recycled Oxide Slurry transferred to existing oxide slurry

distribution system for use at polishers.

• Oxide slurry in Storage Tank does not “settle out” due to

internal recirculation.

Oxide Slurry Ready for Process

PumpStorage

Tank

Recycled Oxide Slurry

ExistingSlurry

Dispense Module

Oxide Slurry Distribution

Existing Slurry Day

Tank

PolishersRecirculation

Fab Integration/Evaluation

ok

ok

2-3 weeks

Analysis of Effluent Customer

Specification of

Slurry

Installation of

System

Test/Tune/Setup

of System

Analysis of recycled

Slurry

Test-run on CMP

Equipment

Release Recycling

System

Needs Optimization

Needs optimization

SLR Module: 1.7m3/hr Pilot System

No Effect To Process Quality

Economic Benefits

Reduced Environmental

Impact

IN SUMMARY, WITH…

WHY NOT

RECYCLE

OXIDE

SLURRY?

Under Development – What’s next?

„Tungsten Slurry Recycling

–Beta system testing confirmed analytical qualities of recycled slurry are within specification.

–Test wafer polishing confirmed removal rate, defects, scratches, adders similar to fresh slurry.

–Extended lifetime of membranes indicate good ROI.

„Ceria Slurry Recycling

–Beta system testing confirmed analytical qualities of recycled slurry are within specification.

–Test wafer polishing confirmed removal rate, defects, scratches, adders similar to fresh slurry.

–Extended lifetime of membranes indicate good ROI.