I am attempting to set up an anodic bonding tool that will be able to
uniformly bond 3" wafers.  At this point I am able to bond Corning 7070
Borosilicate glass to Si wafers but after the wafers have cooled there appears
to be minor defects in the glass surface in the form of 'pits'.  Each pit is
less than 50 um in diameter and hundreds are spread randomly throughout the
glass.  My setup is as follows:

Temp: 400 C
Voltage: 500-1200 V
Time: 1-5 mins
Electrodes: 304 Stainless Steel (lapped and polished on glass contact
surface)

Has anyone ever heard of this?  I have looked through some literature but
haven't found anything like this.

Any help is appreciated!
Brett Swope