SU-8 Spin Speed vs Thickness
|Graphs of Spin Speeds vs Resulting Thicknesses|
|SU-8 5 recipe|
|SU-8 10 recipe|
|SU-8 25 recipe|
|SU-8 3005 recipe|
General Notes about SU-8 lithography, SU-8 adhesion, and SU-8 deposition:
All characterization spins were done on the Headway Spinner. We used the recipes listed in the notes above for each type of SU-8. The thickness obtained may be different than what is shown here because SU-8 thickness seems to vary with the amount of SU-8 poured onto the wafer. The spins used to find the data here were done with approximately a silver-dollar-sized amount of SU-8 pour in the center of the wafer.
SU-8 exposure time and developing time can vary. For very thick SU-8 layers, you may want to increase the exposure time. If you develop and you notice features that were exposed falling off your wafer, it is a good sign that your exposure time is too short. You will need to clean your wafer and start again with a longer exposure time. Over-exposing should not be an issue with a negative photoresist like SU-8. For developing, when you rinse your wafer with IPA, if you notice a white cloudiness, it means that there is still undeveloped SU-8 on your wafer. Dip it back into the developer and gently agitate it for a bit longer. Rinse again and continue until you have no white cloudiness left.