On glass, a dehydration bake improves adhesion. I assume the same is true with sapphire, though I've never used it. On glass, you can also use hexamethyldisilazane (HMDS) to further improve things. You can either use a spin on coating (for an okish layer of HMDS) or vacuum bake / vapor prime coating, from a YES oven, for example, if you want something more controllable. Most likely, there's a little bottle of HMDS sitting by the spinner in your cleanroom. - Kevin Nichols -----Original Message----- From: mems-talk-bounces@memsnet.org on behalf of Evelyn B Sent: Sat 2/7/2009 5:00 PM To: General MEMS discussion; Evelyn Benabe Subject: [mems-talk] Dehydration bake I have seen dehydration bakes used as part of solvent cleaning of glass and sapphire substrates. What is the purpose/advantage of this bake?