Dear friends, I am fabricating gas sensor by using SOI wafer. Because not having suitable chuck for one side etching, I try to passivate one side, then put whole wafer in KOH. Considering etch rate for room temp., I should use 60°C KOH, please recommend one suitable passivation chemicals. Thanks a lot. Sincerely yours Li Song __________________________________________________ Do You Yahoo!? Yahoo! Auctions - buy the things you want at great prices http://auctions.yahoo.com/