Before changing the process I would consider these ideas.

1. Are your glass wafers manufacturered properly and were properly
annealed so they don't have internal stress?

2. Do you have uneven heating? Fracturing would be driven by a
temperature differential across the wafer, not the rate of temperature
rise or temperature itself. Rapid temperature changes are associated
with fractures of ceramic objects, but this is because rapid heating is
often uneven heating, but it isn't directly the cause of fracture.

Providing thermal contact that will more evenly heat the wafers might
well fix your breakage problem.

Ed

-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Don Friedrich
Sent: Wednesday, October 01, 2008 12:15 PM
To: [email protected]
Subject: [mems-talk] OmniCoat baking question

I am seeking a baking process for OmniCoat which is lower T and slower
ramp than recommended by MicroChem.  The recommended procedure of 200C
for 1 minute breaks my glass wafers.  I would appreciate knowing how
others have baked OmniCoat at lower temperatures, such as 120C.

Thank you.

Don Friedrich
JDSU - Advanced Optical Technologies