I suggest you try to use metal  or SiO2 as a mask for this etching.  The
sequence would be to deposit either of these materials, then etch using
photoresist.  Sitrp the photo matertial and etch using the acids.

Good luck.
-----Original Message-----
From: Cheol-Hyun Han 
To: [email protected] 
Date: Thursday, March 26, 1998 12:57 AM
Subject: Looking for polymer films as etching mask against acid


>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.
>