Do not spin the primer.  Use a vacuum vapor primer for total resist adhesion.
If you can not locate one contact me for a free test.

Bill Moffat, CEO
Yield Engineering Systems, Inc.
203-A Lawrence Drive, Livermore, CA  94551-5152
(925) 373-8353

bmoffat@yieldengineering.com

-----Original Message-----
From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org] On
Behalf Of Andrea Mazzolari
Sent: Wednesday, August 15, 2007 3:19 PM
To: guitiz@bu.edu; General MEMS discussion
Subject: [mems-talk] photoresist suggestion

Hi all, i need to pattern a 400um thick silicon nitride film.
I'm planning to use BHF (1:7) to remove silicon nitride from unwanted areas.
Etch rate of silicon nitride is about 1nm/min, so the etch time will be about
400 min.
About photoresist: i've tried to use s1813, but it peel off after about 5 hours
etch.

Here is the procedure i've followed:
spinning of primer
spinning of s1813
soft bake (2 min at 120 °C)
photolitography
hard bake (2 min at 120 °C)

How can i improve s1813 resistance to BHF? May a thicker s1813 layer help ? Or a
longer hard bake time ?
Any idea about an alternative photoresist ?