Terry,

If you wanna use Hydrofluoric acid then thick metals is the only solution as
far as I know. Even if you use a milder etchant 70um will take a long time
and there will be a lot of under cutting.

Ravi


>From: Terry Zhu 
>Reply-To: General MEMS discussion 
>To: [email protected]
>Subject: [mems-talk] Masking layer for pyrex etching
>Date: Tue, 9 May 2006 10:19:57 -0700 (PDT)
>
>Hi,
>
>   Thanks, Ravi and Gareth. I guess the electroplating is needed for 15um
>nickel. It is very thick layer.  Do you think sputtering a thin  layer of
>gold/Cr good for masking layer or other capable thin films?