Why metal? Use Nitride or get Protek from Brewer Science. Joe Lonjin Penn State Nanofabrication Facility College of Engineering -----Original Message----- From: D. Zhou [mailto:dz221@cam.ac.uk] Subject: [mems-talk] Any metal as KOH masking layer? I am just wondering if any metal can act as the masking layer( strong enough in KOH and easy to be removed) for deep KOH etching (say,~600 um deep) at 80 degrees. (It may take about 10 hours to finish the etching process). I tried NiCr (50 nm) but it could not sustain after 2 hours.