Hello,

500 um is a hugh depth, I dont know what is your feature size. SiO2 will
not withstand KOH and there are problems even with TMAH. My suggestion is
that you use Ethylene Diamine + Pyrocatechol mixture, where SiO2 will serve
as an effective etch mask.

Regards
Amit Shiwalkar

aslam muhammad wrote:

> Hi Friends
>
>               I want to use TMAH and KOH as etchant to
> etch bulk silicon ( 500 micron).  which one is more
> suitable.  my etch mask is SiO2.  what is the recipe
> of a good etching rate KOH and TMAH please.
>
> Thankx
>
> M. Aslam




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