Hi Patel,

I had the same problem with another thick resist. In my case I was
overexposing the resist and that is why it was cracking.

Hope this helps!

Sonia.

-----Message d'origine-----
De : PATEL JITENDRA [mailto:jpatel@ENGR.UARK.EDU]
Envoyé : Thursday, October 20, 2005 5:05 PM
À : mems-talk@memsnet.org
Objet : [mems-talk] SU-8 2050 Cracking


I am working with SU-8, 2050, photoresist. I am trying to create 30 micron
diameter vias using SU-8 for copper posts. After expose and develop I notice
that I see cracks around the edge of the vias. Has anyone come accross this
problem? if so, what was the solution. Thanks for your help.
Jitendra Patel

p.s. I am following the processing step as recommend by MicroChem. This is
my process
Clean wafer, Baked, Sputter Ti/Cu/Ti, apply omnicoat, baked, apply SU-8
2050, soft bake, expose using 365nm UV light source, Post expose bake, let
it sit overnight, Develop SU-8 using SU-8 developer, Develop omnicoat using
de-scum.