Dear MEMS colleagues:

For an application in DEP (dielectrophoretic) microfluidics, we use a 1 to
2 micron layer of sputtered SiO2 to cover planar electrodes.  A very thin
layer of photoresist (or other polymer) is then spin-coated to achieve the
proper contact angle.  Can anyone inform us if there might be difference
between SPUTTERED and EVAPORATED SiO2?  In particular, would one expect
either of these two methods to produce a more homogeneous and denser layer?
We are specifically interested in maximizing the dielectric strength of our
coatings, and wonder if there might be some advantage of evaporated layers
with respect to this performance measure.

Also, can one effectively anneal SiO2 after coating to densify the stuff.
If so, what temperatures and times are needed?

We would appreciate hearing any relevant experience or knowledge.

Tom Jones


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Thomas B. Jones
Professor of Electrical Engineering
University of Rochester
P.O. Box 270126
Rochester, NY  14627-0126    (USA)
phone: 1-585-275-5233   fax: 1-585-273-4919
email: jones@ece.rochester.edu
http://www.ece.rochester.edu/~jones
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