Dear Daniel,

If the depth of the the slit is shallow, use focused ion beam.

Nabhiraj

On Thu, Oct 21, 2010 at 7:16 PM, Grimm, Dr. Daniel
wrote:

> Hi guys,
>
> I want to etch a slit (1-2um width at the top side, 200um long) through
> a Si-wafer with 1um thermal oxide on top. I was thinking of a backside
> etch selectively stopping at the SiO2, thus creating a membrane a little
> bit larger than the final slit (I guess, control of the etch rates is
> very challenging). Then, an additional dry etch of the 1-2um slit
> through the oxide by RIE.
>
> Do you know about a good process flow and/or do have any references?
> Anything about a highly selective etchant, which mask (hard or soft) to
> use, how to protect the front side etc.
>
> Best wishes
> Daniel