Andrea HF doesn't react with Silicon. However, once native oxide forms on the Silicon, it will be etched off. I would guess ~15A per hour but I don't know this for sure. Shay -----Original Message----- From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org] On Behalf Of Andrea Mazzolari Sent: Saturday, June 21, 2008 12:43 AM To: General MEMS discussion Subject: Re: [mems-talk] Glass to Kovar anodic bonding Hi all, from my knowledge, silicon is slowly etched by HF. Is this information correct ? Which is the etch rate ? Many thanks, Andrea