Brewer Science has a new material called protek which is specifically
for KOH/TMAH etching. Go to their web site, all the info is there.

Joe Lonjin
Penn State Nanofabrication Facility

-----Original Message-----
From: Liu X.F. [mailto:anodle@126.com]
Subject: [mems-talk] is there anything else replacing SiO2 or Si3N4 for
Sietch mask (KOH)?
   i need etch Si substrate with KOH solution,but i found a 2000A-layer
SiO2 by  thermal oxidization can't resist etch (about 100 minutes),so i
have to deposite a layer of Si3N4? Is there anything else ,which resists
KOH while solutes in organic solvent,such as  light-sensitive lacquer,or
certain  kind of pastern ,can take the place of SiO2 or Si3N4?