Thanks Sarosh for the information I haven't been aware of. Could you provide more details about how HF etches Si? Repetition of oxidation of Si by DI and etching of SiO2 by HF? ----- Original Message ----- From: "Sarosh Khwaja"To: "General MEMS discussion" Sent: Tuesday, June 24, 2008 6:29 AM Subject: Re: [mems-talk] Glass to Kovar anodic bonding Funny, I came across this in Madou today. If I remember correctly, it was around 0.3Å/min in pure HF solution. Principles of Microfabrication by Madou, in the wet-etching chapter, look it up.