This is one of the famous limitations in trying to
integrate standard CMOS with MEMS, and leads people to
use gold as a metal system rather than Aluminum.
You can try a 1:1 mixture of BHF and Ethylene Glycol
this usually reduces the attack of Al somewhat.
good luck

Dave Kharas Ph.D.
Sarcon Microsystems @Sarnoff Corp.


> From: "bobo" 
> Subject: [mems-talk] Etching SiO2 without affecting
> Aluminum
> Date: Thu, 15 May 2003 12:30:50 +0800
> To: 
>
> Dear all,
> does anyone knows what wet etchant can etching
> silicon dioxide without etching aluminum at the same
> time?   Thanks.
>


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