Unfortunately, based on my experience, I think this is a mission impossible.

I don't know why you need a 90 degree sidewall with S1813. If you use S1813
as a mask to perform an anisotropic etching to the layer below (Say, the
device layer of SOI), a sidewall close to 90 deg could be much easier.  You
might need to rethink the whole design.

Jie

On Sun, Jan 17, 2010 at 8:20 AM, Andrea Mazzolari wrote:

> Hi All,
>
> i need to pattern S1813 with vertical sidewalls, but at the present time i
> get an angle of about 54 deg. Awful...
> My maskaligner is an old karl suss.
>
> Here is my procedure:
> -spinning of S1813
> -soft bake 3 min at 115 deg
> -photolitography in contact mode (150mJ)
> -development in MF319 (about 45 seconds)
> -hard bake 15 min at 115.
>
> Any suggestion to improve the sidewall angle ?
>
> Best regards,
> Andrea

*  Zou Jie (Jay)
*  Department of Physics
*  University of Florida
*  Tel: +1-352-846-8018
*  Email: zoujiepku@gmail.com
*  Homepage: http://plaza.ufl.edu/zoujie/