[labnetwork] TMAH alternatives

[Michael Yakimov]

Is there any real safety information on these substitutes, or it's just that they are not as common as TMAH hence not regulated?  I cannot find as much as a proper SDS on any of these.
Remember, TMAH was considered pretty benign until 2005-2010ish when 3 fatal accidents were brought up (hence quoted 75% mortality - 3 out of 4 for major exposure. Along with 20 minor chemical burns in the same dataset). Even then TMAH is a low priority for toxicological research with mostly anecdotal evidence...

Mike




_______________________________________________

Michael Yakimov

Research scientist

College of Nanoscale Science and Engineering

SUNY Polytechnic Institute



253 Fuller rd.

Albany NY 12203



Phone: 518-437-8609 lab

e-mail: yakimom at sunypoly.edu



________________________________
From: labnetwork <labnetwork-bounces at mtl.mit.edu> on behalf of Hathaway, Malcolm R <hathaway at cns.fas.harvard.edu>
Sent: Thursday, June 15, 2023 2:20 PM
To: Labnetwork Mailing List <labnetwork at mtl.mit.edu>
Subject: [labnetwork] TMAH alternatives

Hello Labnetworkers,

Has anyone tried one of the TMAH substitutes that have become available?

How do they work?  Are your users satisfied with their results?

For background, TMAH (tetramethylammonium hydroxide) is widely used in commercial resist developers (3%) and for HSQ developing (25%).  In its 25% concentration, TMAH is a potent contact neurotoxin, which is fatal roughly 75% of the time, for exposures greater than 7.5% of body area.  Nasty stuff.

Several companies now have safer alternatives available, which we'd like to try out, such as:

 Envure 3330 (Sachem Chemical),

E-Grade THEMAH SLM ((hydroxyethyl) methylammonium hydroxide, from Huntsman Chemical), and

Novo-safe SE-33 (ethyl tri-methy ammonium hydroxide from Transene).

We are particularly interested in using one of these as an HSQ developer, so we can do away with 25% TMAH.

Any experiences, good or bad, will be most welcome.

Thanks,


Mac Hathaway
Senior Process and Systems Engineer
Harvard Center for Nanoscale Systems
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