Cheol-Hyun,

> Does anybody know other kinds of polymer films which has good adhesion
> with silicon in acid or the way to increase the adhesion between
> polyimide or parylene and silicon?

The only way I have been able to get polyimide and PR to stick during a
HF:HNO3 etch is to use an adhesion layer of Cr.  Just a 10-20 nm works
fine.  If you can't use this for whatever reason, you might be out of
luck.

--Jonathan