Hi Everyone,

I would like to ask advice for SU-8 processing because this is my first time to
use this famous stuff. I just tried to put down 4-5 um thick SU-8 5 resist and
follow the recipe from MicroChem. However, I did not get anything useful.

The sample was Au coated silicon wafer, soaked in acetone for 5 mins, rinsed
with IPA and dried. The wafers were put in the oven at 150 degree for 20 mins to
dehydrate. Spin coating consists of two steps: 500 rpm, 100 r/s acc for 10
seconds; then 4000 rpm, 500 r/s for 30 seconds. Soft bake was done at 65 C for 1
min then 95 C for 3 mins. Exposure time ranged from 7 seconds to 10 seconds.
Post exposure bake was done at 65 C for 1 min and 95 C for 1 min. Development
was done in EC Solvent for 10 mins.

Most of the features were about 4 micron big with relatively large pitch size.
However, I could not get the features cleared.

Anybody has some ideas or suggestions on this? Any reply will be appreciated.

Thanks,
Yingtao