One reason that you may be having trouble with adhesion polyimide or
parylene on silicon with HF is that the polymer films are porous to HF and
so it will etch the silicon.  This suggests that you will need to find a
polymer that is not permeable to HF, or add another layer of something.

Cheol-Hyun Han wrote:

> Hi;
> I'm looking for a polymer films which I can use as etching mask in acid
> chemical(consisted of HNO3,HF,Acetic acid).
> I have tried with parylene and the problem is adhesion eventhough I use
> adhesion promotor.(it peels up within 10 mins).   And As I know,
> polyimide films has same adhesion problem.
> 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?
> Any information would be welcomed.
> Thanks.



--
John R. Karpinsky  ---  Chief Physicist
MEMS Optical, Inc., 205 Import Circle, Huntsville, AL 35806
Tel: 205-859-1886  Fax: 205-859-5890  Email: johnk@memsoptical.com