Hi All,

      I am in a processing of making SiN membrane by using KOH chemical etching
on SiN(~50nm) coated Si wafers. There are some patterns on one side of wafer,
and I want them intact during KOH etching. The total etching time will be about
5-6 hours.  I am wondering if there is any material/film I can put on to protect
that side of wafer, and can be readily removed afterwards.

Thanks a lot

Xiaoyong





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