I need to do anitropic etching of Si and planning to etch around 200 um.
  As we do not have DRIE we have to do wet etching. I tried KOH solution
  with different kind of masks like PECVD Nitride, Cr, Cr and Gold. But nothing
  survived more than 2 hours. So I am planning to use TMAH for etching.

  What kind of material can  survive without peeling for more than 3 hours in
TAMH?
  I want to use sputter Cr. Is it a good idea? I know a lot of people are using
  oxide and nitrides. But I prefer to use Cr as I have to etch for long time.

  Any suggestions, comments will be highly appreciated.

  Best,

  Ziaur Rahman
  University of Missouri