[labnetwork] Mask of Al in HF

[Peter J Duda III]

Joe
Couple of options here:

  1.  Vapor HF tools work well for mems structures where you need to etch SiO2 in the presence of Aluminum.  Side note: PR doesn't work as a mask for vapor HF either. Two manufacturers are:
     *   Memsstar - https://memsstar.com/mems-tools/vapor-hf-etching/  - We at UChicago have this tool.
     *   SPTS - https://www.spts.com/categories/hf-vapor-release-etch
  2.  Transene Al Pad Etch will etch SiO2 and is designed to minimally etch Al (Ammonium Fluoride based etch).  We have used this with a PR mask.

Thanks
Peter J Duda
Technical Director, Pritzker Nanofabrication Facility

Pritzker School of Molecular Engineering
University of Chicago
5640 South Ellis Avenue
ERC LL178
Chicago, IL  60637
Office: 773-702-8903
Pager/Text:  773-652-0480
duda at uchicago.edu<mailto:duda at uchicago.edu>
pme.uchicago.edu

From: labnetwork <labnetwork-bounces at mtl.mit.edu> On Behalf Of Maduzia, Joseph Walter
Sent: Tuesday, October 26, 2021 3:49 PM
To: 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
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