Hi Ruilin,

I had that porblem once and it was due to insufficient soft-bake temperature.
Check if you have maybe some problem with your hotplate? If that is correct,
maybe you are under-exposing.

Good luck!

Sonia Garcia Blanco, PhD
Researcher MOMS
INO
2740 rue Einstein
Quebec, G1P4S4, CANADA


-----Message d'origine-----
De : 郑瑞麟(Ruilin Zheng) [mailto:zhengruilin@gmail.com]
Envoyé : Tuesday, October 21, 2008 7:23 AM
À : mems-talk@memsnet.org
Objet : [mems-talk] SU-8 layer stick to mask after exposure

Hello, everyone,

I met a problem in SU-8 process recently, the SU-8 layer stick to the mask after
exposure.
I rarely have this problem before. Two weeks ago, I applied an Omega UV filter
for the exposure step to filter out short wavelength UV light.
And this problem appear every time during exposure.
At first I think it may be caused by insufficient soft-bake dose, but after I
tried to prolong the baking time and use higher temperature, SU-8 layer still
sticked to the mask.
Does anyone have some ideas about this problem? Please help me out.

By the way, the photoresist is SU-8 2150 by microchem, will be expired at
Dec,2008.