Sounds like you did not expose the material properly. Gary

-----Original Message-----
From: mems-talk-bounces+garyh=s-cubed.com@memsnet.org
[mailto:mems-talk-bounces+garyh=s-cubed.com@memsnet.org]On Behalf Of
Yingtao Tian
Sent: Tuesday, January 10, 2012 1:27 PM
To: General MEMS discussion
Subject: [mems-talk] SU-8 process development


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