I've recently etched some MOSIS chips using the following:
5% w/w TMAH, 7.5 g/(l of 5% TMAH) of Ammonium peroxy
disulphate+40g/(l of 5% TMAH) of SA at 80C. Using a reflux
condesnor, of course. It's also useful to monitor the pH.

Good luck,
   Mike


>>> username@Eng.Auburn.EDU 05/24/02 12:19PM >>>
Hi,

We were trying to Etch silicon under the cantilever beam through
TMAH(10% W/W in water)+SA(40% in aqeous solution)+APODS(Ammonium
peroxy
disulphate).The entire mixure was heated to 80 degree centigrade.

After the devices were subjected to etching for 1 hour,we could get
some
of the silicon under the beam got etched but the saddest part is the
aluminum bond pads which were open through the passivation
layer(silicon
dioxide about 9000 Angstroms) were completely etched away.

Can anyone suggest me the proper TMAH etching of silicon that should
not
touch the aluminum.

Thanks
Chakry
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