> Message: 11
> Date: Thu, 18 Apr 2002 15:28:41 +0200
> From: "BURRI Mathieu" 
> To: 
> Subject: [mems-talk] SU-8 in KOH bath
> Reply-To: mems-talk@memsnet.org
>
> Dear MEMS society,
>
> I want to protect some alignment marks with SU-8 to etch poly-Si in a KOH
> bath. What happens with SU-8, is it etched? What's the etch rate?....

SU8 will most likely peel off in a KOH bath. it is not directly attacked
provided you cross-linked it properly. but it will peel off and you will
end up with nice membranes of SU8 ! at 80 deg C, it peels off pretty
quickly. You can see bubbles forming on the side of the SU8 structures
forming right away.


> How can I protect these alignment marks in poly-Si in the KOH bath?

As far as I know, only nitride resists in KOH. PECVD nitride won't sustain
 a long etching. LPCVD nitride does.

Joanne.

*****************************
Joanne DEVAL
MAE Dept. MEMS Lab.
ENG IV . 18-111
(310) 825 1350
deval@seas.ucla.edu
*****************************