request for etching SiC with covered metal in lampoly

J Provine jprovine at
Fri Oct 19 14:23:32 PDT 2007

Dear Specmat Committee,
I would like to use lampoly to etch SiC with a mix of HCl and HBr.   
that is fine, but i would like to have metal on the SiC.  The metal  
won't be masking layer and can be covered by oxide and resist for  
masking.  However, there is metal below the SiC membrane, so the metal  
will be temporarily exposed to the etch.

The key is that i want metal on the top & bottom of the SiC membrane  
but not on the sidewalls.

A picture of the process I'd like to try is in the attached powerpoint.

some notes:
1. what metal is used is not that important to me.  i suggest Al  
because it is semi-clean, a good conductor (suits my purposes), and  
much of the lampoly chamber is made of Al.

2. this isn't something i'd need to do many times, just a handful of  
wafers and then it is done.  if it turns out to be something we want  
to do long term another solution will be found.

3. i can organize the etch with staff to coincide with a chamber clean  
if that is helpful.

4. the total area of SiC etched is small (<5% of the wafer).

if another process can achieve the desired endpoint i'd definitely be  
interested in any suggestions you have.  please let me know if there  
are any questions or clarification i can provide.
Thank you.
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