[labnetwork] Mask of Al in HF

[Felix Lu]

Hi Joe –

An HF etch with Al is tough. We had a similar problem about 10 years ago. From what I can recall, we changed the order of operations, evaporating Al through a shadow mask after the HF etch. This of course required a special jig. I’m happy to share more details if this approach is of interest to you.

Best,
Felix
___________________________________________________
Felix P. Lu, Ph.D.
Director of Corporate Engagement

Pritzker School of Molecular Engineering
The University of Chicago
Eckhardt Research Center
5640 S. Ellis Ave., Room ACC104
Chicago, IL 60637

773.834.5063 office

fplu at uchicago.edu<mailto:fplu at uchicago.edu> | pme.uchicago.edu<http://pme.uchicago.edu/>

From: labnetwork <labnetwork-bounces at mtl.mit.edu> on behalf of Maduzia, Joseph Walter <jmaduzi2 at illinois.edu>
Date: Tuesday, October 26, 2021 at 8:07 PM
To: labnetwork at mtl.mit.edu <labnetwork at mtl.mit.edu>
Subject: [labnetwork] Mask of Al in HF
Hello,

Does anyone have any suggestions for mask materials to protect Al in HF 49% for SiO2 removal in SOI wafer? The device is SOI, ICP DRIE etched to glass, HF etch to undercut and free devices, but have Al contact pads and AL is dep’d first. Typically we use PR as pattern mask, but the Al is etching behind the PR. In this case the Al is deposited first, so although order of operations change might help, it’s not a good option atm.

Thank you for any suggestions you might have!
JOE MADUZIA
MNMS Laboratory Specialist

The Grainger College of Engineering
Mechanical Science and Engineering

2239 Sidney Lu Mechanical Engineering Bldg
1206 W. Green
Urbana, IL 61801
217.244.6302 | jmaduzi2 at illinois.edu<mailto:jmaduzi2 at illinois.edu>
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