Photolithography process
Before spin resist it is necessary:
· Clean GaAs wafer piece in NPM hot, ID water, 2-Propanol, ID water.
· Dehydration bake @ 110° C for 5 minutes
Positive Photoresist
Negative reversal process for resist AZ 5214E
Spin-coat resist 5000rpm for 60s
Soft bake at 110° C for 60s
Expose at 10mW/cm2 with UV light for 1.8s (maskaligner MA6 or MJB3)
Bake at 110° C for 60s
Flood expose without mask for 4s
Develop in MF319 developer for 25s and rinse with ID water
Negative Photoresist
Photoresist | Spin Speed/Time | Soft bake Temp/Time | Exposure Time (assuming 10mW/cm2) | Develop Time(Developer MF 319) | Post-Exposure Bake | Thickness |
AZ 5214E | 5000rpm/60s | 110° C/60s | 3s | 20s | 115° C/60s | 1.3um |
AZ 1818 | 5000rpm/60s | 110° C/60s | 4s | 22s | 115° C/60s | 1.6um |
AZ 4533 | 5000rpm/60s | 110° C/60s | 10s | 35-40s | 115° C/60s | 3.5um |
AZ 4562 | 5000rpm/60s | 110° C/60s | 15-20s | 50-60s | 115° C/60s | 5um |