cost efficient organic inline cleaning sen...- common process is a kind of sc1 – psc1 (koh + h2o2)...

ConfidentialPLEASE NOTE THE DISCLAIMER ON THE LAST PAGE

Cost Efficient Organic Inline Cleaning for all Si-Wafer Sawing Processes

2015-06-19

Freiberger Silizium Tage Ilker Sen

Confidential 2015-06-19 2

Content

1. We are Schmid

2. Motivation

3. Comparison sawing process

4. New Schmid cleaning process

5. Results

6. Conclusion

Confidential

1. We are SCHMID

2015-06-19 3

� Owner-operated family business in its 5th generation (1864)

� Over 1,400 employees worldwide

� Sales, production and service in 23 locations worldwide

� 8 production facilities worldwide with over 80,000 m²

� 5 technology centers in all key markets

� DIN EN ISO 9001 certified

� SAP ERP fully integrated

ConfidentialS

OL

UT

ION

S

1. We are Schmid

2015-06-19 4

Photovoltaics

PCB

Display and Optics

Industrial Solutions

Energy Systems M

ark

et/

Cu

sto

mer

Req

uir

em

en

ts

Tool Platforms� Wet Process� Vacuum Technology� High Temperature Process� Printing� Laser Treatment� Automation and Intralogistics� Vision and Inspection

Process Technologies

� Coating

� Structuring

� Cleaning & Conditioning

� Modification

� Handling & Controls

R&

D (

SC

HM

ID T

ech

no

log

y C

en

ters

)

Confidential 2015-06-19 5

2. Motivation

- Alkaline texturizing process is very sensitive for organic residues

- Without special surface treatment no homogenous texturizing of diamond wire sliced wafers possible

- “Schmid clean” process is able to avoid all organic slicing influences

- Common process is a kind of SC1 – pSC1 (KOH + H2O2)

- Instead of NH4OH in SC1 is KOH used in pSC1

Confidential 2015-06-19 6

2. Motivation

- “Schmid Clean” process has lower costs than pSC1 process

- “Schmid Clean” process is easier to control than pSC1

- Removing organic residues after all sawing processes

(oil, slurry, water based coolant)

- Preparing wafer surface for alkaline texturizing

Confidential

3. Comparison sawing process

2015-06-19 7

Slurry / Oil process ( PEG / Oil +SiC) Diamond wire + water based coolant

Wire

Slurry

(Loose abrasive)

SiliconSilicon

Diamond layer

(Fixed abrasive)

Core wire

Feed

wire

Used

wire

Slurry

nozzle

Cut

direction

Silicon

brick

Slurry

nozzle

Wire direction

Feed

wire

Used

wire

Coolant

nozzle

Cut

direction

Silicon

brick

Coolant

nozzle

Wire direction

(Pilgrim mode)

Confidential 2015-06-19 8

3. Comparison sawing process

W

a

W

a

W

af

er

fe

r

Steel wire

D

i

a

m

a

n

t

d

r

a

h

t

� PEG / Oil Slurry sawing process� Diamond wire sawing process

� Slicing direction continues � Slincing direction forward andbackward

� Diamond wire

Confidential 2015-06-19 9

4. New Schmid Cleaning process

- Problem:

- Different sawing processes (slurry, oil, waterbased coolant)

- Influence of sawing process to the wafer surface

- Influence of coolant to the wafer surface (Diamond wire process)

- Combination of oxide layer defects and organic residues

- Customers are using different wafer suppliers with different cleaning processes

- Different texture results

SC

HM

ID G

roup

Confiden

tial

10

4. New Schmid cleaning process

2015-06-19

Pic. 1: Wafer after standard

cleaning not optical clean

Pic. 2: Wafer after standard

cleaning optical clean

Both wafers have

problems in alkaline

texturizing:

Optical clean is not

clean enough

SC

HM

ID G

roup

Confiden

tial

2015-06-19 11

4. New Schmid Cleaning process

2. Solution:

- Searching for a process, which is able to replace H2O2

- Searching for a process, which is very robust and stable in

comparison pSC1

Working principle:

Org (C) + Ox → CO2↑ + Red

SC

HM

ID G

roup

Confiden

tial

4. New Schmid Cleaning process

SC

HM

ID G

roup

Confiden

tial

4. New Schmid cleaning process

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

CompetitorInline

SCHMIDreference

New SCHMIDClean

Cle

an

ing

Co

sts

pe

r W

afe

r, in

de

xe

d

Costs Benchmark for Cleaning withOxidation Step

COO Materials / Consumables Costs

2015-06-19 13

SC

HM

ID G

roup

Confiden

tial

5. Results

2015-06-19 14

� No organic and metallic residues

� No visible contamination: oil/grease, finger prints, water stains, slurry stains, coolant stains

� All organic masks are removed

Etch rate per side [µm] Reflection [%](400-1000 nm)

Remarks

6,0-6,5 11,4-11,0 Very uniform surface in

texturizing and better VOC

SC

HM

ID G

roup

Confiden

tial

6. Conclusion

2015-06-19 15

� “Schmid Clean” process is a very robust and stable process

� Replace H2O2 through cheap and common available chemical

� Very low working concentration

� Better etch rate in texturing process and better reflection

� Reduced costs for consumables

� No special waste water treatment necessary

� Inline process

� Low temperature process

SC

HM

ID G

roup

Confiden

tial

www.schmid-group.com

THANK YOU FOR YOUR ATTENTION!

2015-06-19 16