Dear Aslam,

SU8 can not be etch by KOH, however if you plan to use it as a mask for
etching other material e.g. silicon. It will NOT work at all.
Reasons:
1. SU8 has poor adhesion for any material and this is more noticeable when
   it is in an aqueous environment. Your SU8 mask will come off.
2. Also SU8 is very sensitive to thermal stress so, putting your sample at
   90C will contribute to lift off the SU8 mask.
3. Even if you use SU8 adhesion promoter, it will not work. As the
   solution recommended for removing the adhesion promoter is as well an
   alkaline solution.

If you are thinking to use SU8 as an etch mask, I would recommend you to
use dry etch. It works really good. I have dry etched 800um of Si using an
SU8 mask!

Good luck
Gabriela Juarez-Martinez
Dept. Electronics
Glasgow University.

> Date: Thu, 12 Dec 2002 03:34:18 -0800 (PST)
> From: aslam muhammad 
> To: mems-talk@memsnet.org
> Subject: [mems-talk] SU 8 PHOTORESIST
> Message-ID: <20021212113418.93003.qmail@web10808.mail.yahoo.com>
> Content-Type: text/plain; charset=us-ascii
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> Reply-To: General MEMS discussion 
> Message: 3
>
> Hi all
>
>   it will be a great favour if anybody let me know
> whether SU 8 photoresist withstands in KOH OR TMAH (
> at 90 degree celcius).
>
> thanks in anticipation
>
>
> M.Aslam
>
> __________________________________________________