I agree with Gareth, just skip the HMDS prime. You really shouldn't need
it on the glass. I wouldn't even worry about the dehydration step he
said, if you are using a standard positive DNQ resist (like S1800),
adhesion and wettability to glass should be fine and I don't think the
small amount of water vapor in the glass is going to affect much. 95% of
our work is on standard soda lime glass, and we rarely use HMDS.

Sincerely,
David Casale
R&D Engineer
www.maxlevy.com
Max Levy Autograph
2710 Commerce Way
Philadelphia, PA 19154 USA
tel: 215-842-3675

-----Original Message-----
From: Gareth Jenkins [mailto:[email protected]]
Sent: Thursday, October 21, 2010 3:15 AM
To: General MEMS discussion
Subject: Re: removal of HMDS without affecting the photoresist

Could you not simply skip the HMDS? If I recall correctly, I used to coat
resist on glass without it. We would bake it at 300 deg C to thoroughly
dehydtate it first.

Additionally, some standard resists include their own primer.