Dear MEMS experts,

    I am making some very thick patterns (thickness: ~0.7mm)with a
negative photoresist EPON SU-8 bought from Microlithography Chemical corp.
The process is basically the same as described by M. Despont et.al. in
their paper "High-aspect-ratio, ultrathick, negative-tone near-UV
photoresist for MEMS applications". But the EPON patterns I made have very
sharp edges, as I can see from the vertical profile of the
structures, the EPON surface layer extends out in a sharp angle like
a bird's beak. I wonder if anyone experienced the same problem and knows
how to get rid of the problem. Any comments/suggestions from you will be
highly appreciated.

- Hui

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Hui Tang

Research Assistant
BioMEMS Labratory, Beckman Institute
ECE Dept., Univ. of Illinois at Urbana-Champaign
Tel: (217) 265-0827(Lab), 333-0188(O), 356-7637(H)
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