Dear Hadi,

You better use a convection oven with gradual change in temperature for
every bake.
I want to suggest you use AP300, a kind of adhesion promoters from silicon
resources to reduce the residual stress difference.
Good Luck!

Sanghyo Kim

****************************************************************
Sanghyo Kim, Ph.D.

Sr Researcher
Dept. Electrical & Computer Engineering & Computer Science
Center for Microelectronic Sensors and MEMS
University of Cincinnati
Cincinnati, OH 45221-0030
Phone (513) 556-0903
Fax (513) 556-7326
***************************************************************


> Message: 2
> Reply-To: [email protected]
> From: "Muhammad Hadi" 
> To: [email protected]
> Date: Fri, 26 Oct 2001 00:41:58 +0600
> Subject: [mems-talk] Adhesion problem of SU-8 over SiO2
>
> Hi everyone
>
> I'm facing a severe problem of stripping off of the patterned Post
> Exposed Baked resists [negative resist, for both SU-8 25, SU-8 100 ]when
> the wafer is immersed into a BOE solution.
>
> I am following the receipe bellow for SU-8 100 from MicroChem
>
> Substrate: SiO2 over Si
>
> Clean: using acetone and methanol in an ultrasonic bath, rinsed in  a DI
> tank.
>
> Dehydration Bake: at 200C, over a hotplate, for 10 min
>
> Spin Coat: for 10 sec upto 500rpm/s and then 30 sec upto 3000 rpm/s
>
> Pre Exposure Bake: using hot plate,10 min at 65C, then 30min at 95C
>
> Exposure: Sufficient [e.g. 60 sec UV exposure in a Cobilt Alligner]
>
> Post Exposure Bake: using hot plate 3 min at 65C, then 10 min at 95C
>
> Develop: 10 to 15 min in Nano SU-8  developer
>
> Rinse and Dry: Rinsed with IPA and Nitrogen blow dried.
>
> But when i dip this wafer into BOE, the patterned  resist just comes off.
> Where is the mistake that i'm doing in all those steps??
>
> I'd appriciate any sort of suggestion as i need to overcome this problem.
>
> Thanks
>
> M A Hadi
>
> CISM- The Ohio State University
>
> Columbus, Ohio