- substrate cleaning-AMI clean
- acetone rinse
- methanol rinse
- IPA rinse
- Omnicoat spin-coating
- 500 rpm, 5s, 100 rpm/s
- 3000 rpm, 40s, 300 rpm/s
- Bake at 200 deg. for 1 min
- Repeat this process at least two (~26nm expected for 2 layers)
- 3 times recommended -> Microchem suggest 3 layers of Omnicoat coating
- SU8-3005 spin-coating
- Dispense it to cover 70% of the wafer surface
- 500rpm, 5s, 100rpm/s
- 4000rpm, 40s, 300rpm/s ->5.5um
3000rpm, 40s, 300rpm/s ->6.7um
- soft bake
- Bake at 95 deg. for 3 mins.
- Exposure with the MA6 Aligner
- CI1 setting for 30s exposure in Hard contact mode (typically for large patterns like back-side opening masks)
- Note : 10 s exposure / 1 min development for ANP rev.1 & 2 bondpad etch (8.5 s exposure also works good)
- Note : 8.5 s exposure / 1 min development for ANP rev.2 slit etch mask
- Note : For the small 5 um vent hole patterns, I ended up reducing 6.5 s exposure time with 3 layers of Omnicoat
- Note : If you perform vacuum contact with SU8, it will stick to your wafer and hard to retrieve wafers…
- CI1 setting for 30s exposure in Hard contact mode (typically for large patterns like back-side opening masks)
- Exposure with the EVG Aligner
- …
- …
- Post Exposure Bake (PEB)
- Bake at 95 deg. for 2 mins
- Development
- Prepare two dishes for SU8 developer and IPA
- Agitate sample in the SU8 developer dish (1min)
- Put sample in the IPA dish, agitate and spray IPA and dry using N2 gun
Note: Do not rinse with DI water after IPA spraying
- Omnicoat development
- O2 Plasma etch in Oxford RIE 80 for 2 mins
- Recipe: YS Omnicoat removal
Note: Etch recipe – Foward power : 100W / O2 : 35sccm / 190mT / 30s by Omnicoat manual
Note: Total 2 min etch = 3 x each layer for 30s etch + 30s overetch