Mike,
Most implant species  will not move during the bonding process. However, the
Pyrex you are bonding to contains lot's of sodium which diffuses real well
at those temperatures and ever at room temp. it might end up in you gate
oxide and kill the active device. You should have some getter layer on the
silicon i.e. PSG. Also, it is rather difficult to bond Pyrex to nitride.
Usually this is done using 7070 Pyrex at ~ 450 deg which it too hot for CMOS
metallization.

Shay

-----Original Message-----
From: Michel Godin
Subject: [mems-talk] Anodic bonding - implant damage?

We're interested in encapsulating some electrolyte-insulator-silicon (EIS)
sensors in glass microfluidics.  My question is whether anodic bonding of
the pyrex will cause damage to the implant traces required in the sensor
design.  I suppose the temperatures are too low to cause damage, but will
the large electric field or ion migration be a problem?  It should be
pointed out that the implants will be covered by 800 nm of nitride, so
direct bonding of the pyrex will be to the nitride.  But there will some
windows in the nitride where the underlying silicon will be exposed to an
air gap (fluidic channel ~ 3 microns) between the pyrex and the surface.
Any insight or references would be greatly appreciated.