20210310

• Started with new SU8
• Took it out from the fridge at 09:00
• Transferred to a new syringe
• Let out inside alu foil to thermalize
• new wafer cleaned for dust with IP, plasma treated and then 160 C for 7-8 min
• changed spin program to 970 rpm to achieve 890 rpm on the readout -> 100 um thick layer.
• transferred su8 from syringe
• forgot to leave it some minutes on the wafer to thermalize before spinning
• spun for 60s at 890 rpm (readout)
• leave for 10 minutes on spin coater
• to keep the hot plate at 95C beyonf 99.9 min I programmed a third period: 40 + 80 min
• back 4 hours later due to a belated meeting
• turned the mask the other way because I checked once more which was up and it was confirmed by what I saw in the microscope
• transferred wafer to UV-KUB, had the light on for some seconds (big mistake)
• chose 600 um thickness to press mask onto wafer (see later: maybe not enough?)
• used 44s at 50% to have 1000 mJ/cm^2
• post baked
• developing delayed 2-3 hours due to meeting (is this bad?)
• Same problem as before:
  • small structures are not removed by developer
  • differences on the wafer in how well small structures are developed
  • developed 5 min according to table, but no small structures developed
  • continued several rounds up to 11 min, from 8-9 min nothing seemed to change