Dear MEMS colleagues,
we are trying to fabricate thick photoresist (30-50um) structures on
silicon substrates.

We are using the resist AR-P 322, lambda 308-450, and developer AR
300-26 from the company Allresist in Berlin, Germany. The exposing is
carried out with an Electronic Vision mask aligner.

The obtained aspect ratio is rather poor. The angle included by the
side-walls and the substrate surface is around 60 deg. No difference
was observed using chromium or photo emulsion masks.

Any suggestions on how to approach the ideal case of vertical side-
walls are apreciated.

Torsten Gerlach

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Technical University of Ilmenau
Dept. of Micro System Technology
P.O. Box 0565
D-98684 Ilmenau
F.R. Germany
phone: +49 / 3677 / 69-1295,   fax: -1296
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