Hello Sunil

Exactly what kind of etch profile are you looking for. Are you trying to release
or undercut a device or is the V shape from the wet etchants important. If a
purely isotropic etch would work, xenon difluoride is a dry gas phase etch that
has better than a 1000 to one selectivity vs. oxide and no attack on Al. It has
been used for many applications with a mixed oxide, Al device. Please contact me
if you would like more information. We might be able to set up a way for you to
try it out.

David Springer
XACTIX, Inc.
[email protected]

>>  Sunil,
>>  Thanks a lot.
>>  But I am wondering some Si Etchant(eg. KOH, TMAH) which will not attack
>>  SiO2 and Al. Sorry about the confusing.
>>  Johnny


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