[labnetwork] TMAH alternatives

[Graham Gibson]

   Hi Mac,

   I have tried Huntsman's E-Grade THEMAH as well as another of their products, E-Grade CHOLINE OH, as a developer for standard Novolac photoresists, though not for HSQ (yet). I was pretty happy with their performance in general, though THEMAH was a bit slow compared to standard TMAH developer.

  Cheers,

Graham Gibson

Operations Manager, NanoFabrication Kingston
Queen's University
945 Princess Street
Kingston, Ontario, Canada
K7L 0E9
gibsong at queensu.ca<mailto:gibsong at queensu.ca>
www.nanofabkingston.ca<http://www.nanofabkingston.ca/>



From: labnetwork <labnetwork-bounces at mtl.mit.edu> On Behalf Of Hathaway, Malcolm R
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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