20210309
From mn.fysikk.laglivlab
Continued from yesterday
- Had left the insolated wafer on the hot plate over night. This means 15 hours rest instead of 10 min.
- Table says 5 min develop.
- I used new PGMEA
- After 3 minutes I noticed white structures in the region around the main structures. I did not understand what this signified
- After 5 min I rinsed with isopropanol (IP)
- I struggled to get good view in the microscope. Therefore I miscalculated what I saw and thought I needed to develop more.
- I developed about 30 s more.
- In the microscope it was now clear that the structures where overdeveloped and all the smallest features where erased.
Time to start again
New try
- Use new wafer and go straight for plasma cleaning
- Skip heating and do spinning
I lost all my edits! Obviously it's important to save before leaving idle
- SU8 to wafer using syringe worked perfectly.
- Used a single spin: ramp 100, 900 rpm at 40s
- Display said it only spun at 830 RPM
- Noticeable bulge at edge of wafer. Tried to wait for an hour, but it did not change much.
- Transferred to hot plate: 65C 15min, 95C 90 min, should be 120, but display only has 2 digits. time manually.