I didn't reply to your post! Maybe you saw my response to another
similar post?
Such a thick masking layer shouldn't be necessary if a less aggressive
etching solution is used (see
http://mail.mems-exchange.org/durusmail/mems-talk/17552/ ). A few
hundred nm gold/Cr should be OK.
I don't have much experience with Pyrex. I know it etches slower than
soda-lime but I'm sure 70um is possible (only isotropically though).


Terry Zhu wrote:

>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?
>
>
>