- Opened new package of 4" wafers
- Plasma treated + 15 min+ @135C
- SU8 spread 60s@600rpm, then 40s@1700rpm for 50 um
- Both wafers have several holes in su8 layer, I do ont know if this is due to dirt/dust on wafers or tiny air bubbles in SU8. 2nd wafer I tried to mend initial holes, but it did not help.
- Not much SU8 left in syringe, maybe that is whey there were air bubbles? Removed stock bottle from fridge to replenish SU8 in syringe before end of day.
- 11:15 prebake started on VWR hotplate
- One of the wafers had completely irregular SU8, useless!! The other had several holes, but some usable areas. => we need to clean the wafers!!
- Exposure: 34s@25% intensity = 400 mJ/cm^2
- Post-bake 15min@65C, 40min@95C
- Development: small holes did not develop