Andrea,

You don't mention the etch depth, the masking material, or what very very low
roughness means. When I needed to develop a well controlled shallow silicon etch
in a production environment, I ended up using 40% KOH and water at 60 degrees.
The high concentration KOH reduces any etch loading effects (local areas in
cavities where the surface is starved for fresh etch solution) and the surface
is less rough than lower concentrations. The etch rate was closer to 30 um/hour
if I remember correctly.

Dan Chilcott

-----Original Message-----
From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org] On
Behalf Of Andrea Mazzolari
Sent: Saturday, February 06, 2010 5:54 AM
To: General MEMS discussion
Subject: [mems-talk] Silicon etch low roughness

Hi All,

i need to etch (100) silicon at low etch rate (not more than 20um/hour) and i
need very very low roughness.

I can not use HNA solutions, i can use KOH or TMAH with surfactants.
Any suggestion about the optimal etching condition for this job ?

Thanks,
Andrea