Moisture and contaminations are the leading causes for resist
lifting.  You may want to ensure a clean, dry substrate before applying
photoresist (pre-clean and bake).  Then you may also want to use an
adhesion promoter (HMDS).  Good luck.

       Ron Martin | Systron Donner Automotive
  Job Title: Photolithography Engineer | Location:
      Concord, CA | Extension: 6563 | Outside:
                   1-925-671-6563
             E-mail: rmartin@systron.com



---- Original message -----
From: madhav rao  
Subject  [mems-talk] Photolithography -  Resist peeling

Hi,
       I am experiencing a problem in patterning on silicon-di-oxide
wafers; I am using SHIPLEY 1818 resist to get a thickness of 2.5 micron; 6
seconds of exposure time. After developing for 60 seconds, I observe, the
resist layer peels off; leaving no patterns on the wafer. Also I had
soft-baked the resist at 95 C for 2 minutes in hot-plate.
This seems strange to me, as a month ago, I had successfully transferred
the patterns on to silicon-di-oxide wafers.
I am using mylar film masks.
Please let me know, if any one had experienced similar problems before; and
if so, could you let me know suggestions to solve ?

Thanks

Regards,
Madhav Rao,
Graduate student,
University of Alabama.