Use Pad Etch 4 from Ashland. See JMEMS Etching for Micromachining Processing II paper online for etch rates. --Kirt Williams ----- Original Message ----- From: "polly"To: Sent: Thursday, October 06, 2005 4:54 AM Subject: [mems-talk] how to etch SiO2 without etching underlying Aluminum > > I would like to know what are the etchants for etching SiO2 without > etching underlying ALuminum