Hi,

I assume that MEMS people have to live with such conditions, and know how to
deal about them.

We will soon need to pattern spin coated photoresist on deeply etched  (7 um
deep and vertical trenches,  aspect ratio up to 1) wafers.   We do not have
much experience in patterning such structured samples.  We are expecting
problems of covering the edges, and exposure/development of the thicker
areas.

What would you suggest ? could we still use our regular photoresist (1-1.7
um thick) with double spin coating ?
Would we need a higher transparency photoresist to expose through the thick
areas ?  Would a planarization step using for example polyimide to fill the
etched areas before the photoresist spin coating work better ?

Any comments/suggestions/references would be appreciated.  Thanks,

Boris Lamontagne
Institute for Microstructural Sciences
National Research Council
Montreal Road, Building M-50
Ottawa (Ontario) Canada  K1A 0R6

[email protected] 
613-990-7434
fax 613-990-0202