Outline

 ? 1. Dry film photoresist working mechanism 

 ? 2. Process temperature vs process time 

 ? 3. Water content (moisture level) vs stripping performance 

 ? 4. Bath-life study without wafer loading

 ? 5. Bath-life study with wafer loading 

 ? 6. Metal corrosion study 

 ? 7. ZS-200 failure mode & root cause

 ? 8. Monitoring method 

 ? 9. Strength of ZS-200 

 ? 10. ZS-200 process control flow

Dry film Photoresist Working Mechanism

Dry film Photoresist Stripper Working dissolve Mechanism

Process temperature vs process time

Process tool: beaker with stirrer 

 ? Test vehicle: ASE test wafer coupon (2.5x4cm) dipping in 50g stripper 

 ? Metrology: Optical microscope

 ? Split condition test procedure:

– Process temperature: 50 to 90 C

– Record break through time

– Residual PR amount compariso

Process temperature vs process time

ZS-200 is capable to strip off ASE dry-film resist within 50~90C. Shorter process time required for higher temperature.

Water content (moisture level) vs stripping performance

Process tool: beaker with stirrer

 ? Test vehicle: ASE test wafer coupon(2.5x4cm)

 ? Metrology: Optical microscope

 ? Prepare 4 stripper sample with different H2O contents:

– (1) stard (2) +5% DIW (3) +10% DIW (4) +15% DIW

 ? Test stripping time PR removal performance by break trough time residual PR amount 

Water content vs stripping performance

Performance of ZS-200 is not sensitive to water content. Higher water content resulted in a little shorter process time but may have lower resist loading shorter bath-life.

Bath-life study without wafer loading 

 Process tool: beaker with stirrer (w/o cover) 

 ? Test vehicle: ASE test wafer coupon (2.5x4cm) 

 ? Metrology: Optical microscope 

 ? Heat the stripper bath to 70C up to 48 hours

 ? Record evaporation amount every 4 hours

 ? Collect 200mL sample every 4 hours 

 ? Do PR stripping capability test using the collected stripper samples

Bath-life study without wafer loading

ZS-200 bath life without wafer loading: 72°C

Bath-life study with wafer loading

Process tool: beaker with stirrer (w/o cover) 

 ? Test vehicle: ASE test wafer coupon (2.5x4cm)

 ? Metrology: Optical microscope 

 ? Heat the stripper bath to 70C

 ? Do 1 coupon stripping in beaker each time continuously up to 20 coupons 

Bath-life study with wafer loading

ZS-200 bath life with wafer loading: 12hr

Metal corrosion study by analyzing dissolved metal contents in stripper bath

Process tool: beaker with stirrer (w/o cover)

 ? Test vehicle: ASE test wafer coupon (2.5x4cm) 

 ? Metrology: ICP-AES 

 ? Do 1 coupon (2.5x4cm) stripping in 100mL bath for each split condition

 ? Collect stripper sample do metal contents analysis using ICP-AES 

Metal corrosion study by analyzing dissolved metal contents in stripper bath

ZS-200 Failure Mode & Root Cause

Incomplete Photoresist Removed 

 a. Solubility saturation

 (1) Photoresist solid content too high 

 (2) H2O out of range b. Air oxidation/thermal degradation of bond-breaking agent ?Metal Film Corrosion a. pH increase due to increase of H2O% 

 b. Air oxidation/thermal degradation of corrosion inhibitor 

Monitoring Method

1. H2O content: Karl-Fischer titration

 2. Amine content: pH meter titration 

 3. Metal corrosion: Cu etch rate 

Strength of ZS-200

  ?High bp, low evaporation: 

– No/low odor at process 

– Low volatile consumption/low VOC pollution

– Longer bath life 

 ? No hazardous component used:

– No NMP, no DMAc, no DMF, no catechol 

 ? Low waste treatment concern:

– No DMSO or any sulfur

-containing component (cause waste water treatment issue)

– All components can be incinerated (low waste treatment cost) 

Strength of ZS-200

  ?Performance is not sensitive to H2O content:

– Large H2O tolerance window

– No severe environmental control necessary for processing

– Easy to control product (ZS-200) spec/performance 

 ? Low metal corrosion:

– Extremely low Cu loss in stripping process

– Low Al loss 

ZS-200 Process Control Flow