You may try KOH etch with high concentration at low temperature to get good
surface finish.

You can also try DRIE followed by smoothening etch by ICP or buffered HF for
few minutes. Again you would be experiencing rounded corners instead of
sharp corners in this case.

Regard,
Prasanna

On Mon, Aug 17, 2009 at 4:35 AM, renil kumar wrote:

> Hi all,
>
>               I want to etch smooth vertical walls of depth 70 um in <110>
> oriented silicon. what is the best etch recipe to get a smooth wall of width
> 5um and a depth of 70um. any suggestion would be appreciated well, thanking
> you

--
Thanks & Regards,
Prasanna Srinivasan