Dear friends,

i am trying to do TMAH etching of silicon under the
cantilever beam  made of (silicon
dioxide+polysilicon).

We have used the solution of TMAH(10% w/w in
water)+SA(40% aqueous solution)+Ammonium peroxy
disulphate(APODS about 1.25gms).

we have heated the entire solution @ 80 degree
centigrade and chips were etched in this solution.

But,we could see that Al bond pads,which were opened
thru silicon dioxide passivation layer(9000 Angs)were
attacked by the etching solution.

Can anyone of u please suggest me any good etching
technique for silicon that should not attack Aluminum.

thanks
Chakry

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