Hi all,

I'm handling with SOI wafer. I've completed depositing Al as hard masks on
both front-side and backside for DRIE etching. Currently I performed DRIE
etching for the front-side layer. The silicon on front-side is removed and
silicon oxide layer is then exposed.

Now I need to perform a long time DRIE etching for backside layer (around
1.5 hours). But I cannot find a good way to protect the front side structure
which is 10um thick. The material I plan to use is photoresist with
thickness of 1.3um. I'm not sure whether it can well protect the front side
structure.

Do you have any suggestion for front side protection?

Thanks,

Li. Zhang
Graduate Student
Edward P. Fitts Department of Industrial and Systems Engineering
North Carolina State University
Raleigh, NC 27695-7906
USA
TEL: (919) 413-5459
Email: lzhang13@ncsu.edu
Web:  http://www.ise.ncsu.edu
         http://www.nnf.ncsu.edu