Bill, You need an ion barrier on the glass face such as Si3N4 to trap the Na+ ions, an oxide surface must be on the opposite side on layer 2 that is to be bonded against the ion barrier. Best regards, Julian. ----- Original Message ----- From: "Bill Moffat"To: "General MEMS discussion" Sent: Tuesday, May 18, 2010 8:29 PM Subject: Re: [mems-talk] SiO2-Glass anodic bonding Plasma bonding works. Bill Moffat