Rob Any Pyrex from a good supplier will do. 40/60 is good enough. The bond quality in anodic boning lies in the surface preparation and the bonding process. The scratch and dig specs are relevant only if your seal width is narrower than a visible scratch and a dig diameter which is unlikely. Shay -----Original Message----- From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org] On Behalf Of Robert MacDonald Sent: Tuesday, April 28, 2009 10:29 PM To: mems-talk@memsnet.org Subject: [mems-talk] scratch and dig specs for anodic bonding Does anyone have standard specifications for pyrex wafer surface finish to achieve a good hermetic anodic bond to Si (assuming good conditions). In particular, I'm looking for a scratch and dig spec, or a surface roughness specification. Thanks, Rob MacDonald