In my experience,
1. Ti/Au will likely peel off if features are small.
   Sometimes it's easier to metallize after the through holes are
   etched.
2. I've not used TMAH
3. KOH doesn't seem to damage the LPCVD Nitride.
-- Jon

On Tue, Apr 09, 2002 at 05:09:36PM -0500, Gao, Yuanfang  (UMC-Student) wrote:
> Dear all,
>
> I plan to use anisotropic wet etching to etch through holes in a <100>silicon
> wafer, using LPCVD silicon nitride as mask layer,
> also there is a exposed Ti/Au layer(Ti act as a adhesion layer)
> on top of silicon nitride.
> My concern is:
>
> 1. Will Ti/Au layer resist the long time KOH etching?
> 2. If KOH doesn't work, will other etchants like TMAH do?
> 3. Will KOH etching damage the silicon nitride membrane?
>
> Thank you very much!
>
> Yuanfang Gao
>
> University of Missouri
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