20210430 photolitho

• Started LAF-bench
• N2 valve had been left open, almost no pressure left!
• cleaned wafers with plasma only
• 1st wafer
  • 3700 RPM ~ 20 um
  • prebake on programmable hot plate
  • Masking with UV-Kub 2. UV at 11% intensity for 30 sec.
  • Hot plate too hot, 65C postbake happened at 72-66C
  • The hot plate seems to take longer than the timer on my telephone. This needs to be checked!
  • development with PGMEA for 2:45 was too long time! Misjudged the residue and continued another 30s, then it was completely destroyed.
• 2nd wafer 3100 RPM ~ 25 um
  • prebake on VWR hot plate, no nice control of ramp in temp
  • Masking with UV-Kub 2. UV at 11% intensity for 30 sec.
  • Postbake on VWR hotplate
  • Developed 3min in PGMEA gave perfect sylinders and gaps between them. quick dip to remove a little residue and done.