One thing is the soft bake is too short.  With 20 micron thick resist I
had to use 1 hour soft bake at 90C.  If I had the choice I would use
vacuum soft bake.  If you do not get rid of all the solvent your
exposure and develop become variable.
Bill Moffat, CEO
Yield Engineering Systems, Inc.
2185 Oakland Rd., San Jose, CA  95131
(408) 954-8353


-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of sebastian wicklein
Sent: Wednesday, October 11, 2006 2:58 PM
To: 'General MEMS discussion'
Subject: [mems-talk] AZ 9260

Dear MEMS-Experts,

When I'm developing a 28micron thick AZ9260 photoresist with the AZ400K
developer in 1:4 dilution (Developer:H2O)on silicon, I can see a
selective developing rate between thin lines and square areas that have
a much bigger diameter.
Since I have such a selectivity, my lines are flaking off when I use
longer developing times in order to develop the squares as well!

Can someone tell me what's going on here?

Overview of procedures

Spin 28microns on Si-sample
Softbake 10 min at 50 degree C
Softbake 30 min at 90-95 degree C
Exposure 40 min at 10 mW / cm cubic
Development in 1:4 dilution (Developer:H2O)