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Date: Tue, 27 Jun 2023 13:01:16 -0400 |
Subject: [labnetwork] Spin Coater Chucks Vendors? |
Message-ID: <CACeLyv4LChyedwaroZTd6ExN6mBbVnqSdHH3VWyBN5JoFFP14g@mail.gmail.com> |
Dear Labnetworkers, |
We are planning to order some new spin coater chucks (1/2" ID with a notch |
for CEE 200cbx) that fit 3-4" wafers. Previously we tried CEE and Laurell |
Technologies. I was wondering if you guys have other recommended vendors? |
Just wanted to explore all the options we have. |
Many thanks, |
Chao |
-- |
*Zhichao (Chao) Wang, Ph.D.* |
*Lithography Engineer* |
*UDNF* |
*University of Delaware* |
*Pronouns: He/Him/His* |
*------------------------* |
*Office Number?(302) 831-4839* |
*221 Academy St.?RM170* |
*Newark, DE 19711* |
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From yakimom at sunypoly.edu Wed Jun 28 14:11:40 2023 |
From: yakimom at sunypoly.edu (Michael Yakimov) |
Date: Wed, 28 Jun 2023 18:11:40 +0000 |
Subject: [labnetwork] TMAH alternatives |
In-Reply-To: <DM6PR07MB65212B24FFAD5101AFFD4C18CB23A@DM6PR07MB6521.namprd07.prod.outlook.com> |
References: <MN2PR07MB6526C0C512E36FF68083D2EBCB5BA@MN2PR07MB6526.namprd07.prod.outlook.com> |
<YQBPR0101MB5521CEB79A1B6E2CD711CB47C359A@YQBPR0101MB5521.CANPRD01.PROD.OUTLOOK.COM> |
<DM6PR07MB65212B24FFAD5101AFFD4C18CB23A@DM6PR07MB6521.namprd07.prod.outlook.com> |
Message-ID: <BY3PR05MB8260B76FA436278D863E85B3CE24A@BY3PR05MB8260.namprd05.prod.outlook.com> |
With some sick time I had to endure, I went down the rabbit hole of TMAH and similar compounds toxicity. Scientific archeology is fun! |
First, TMAH isn't a good thing to study - corrosive effect of being a base doesn't allow good study of TMA ion, so salts like TMA chloride are better test materials. |
With that, even those papers are not very abundant. Some of latest TMAH work is purely TMA, no comparisons. I actually happened to briefly talk to Ernst Timlin from IBM about things they did - that was a while ago though. I assume their briefs are a big part of current motivation: |
https://sesha.org/abstract/tetramethylammonium-hydroxide-tmah-toxicity-and-methods-to-reduce-risk-in-the-workplace/ |
Second, TMAH oral LD50 by weight is something like a cup of CD26 developer for my weight. So I am not surprised when they say rats given half of that dose look strange - if you know the taste of TMAH, you would certainly understand those poor animals! |
Most relevant papers - and looks like any relative safety claims are based on that - are |
Hunt, Reid. "Some effects of quaternary ammonium compounds on the autonomic nervous system." Journal of Pharmacology and Experimental Therapeutics 28.3 (1926): 367-388. |
https://jpet.aspetjournals.org/content/28/3/367.short |
Burn, J. H., and Henry Hallett Dale. "The action of certain quarternary ammonium bases." Journal of Pharmacology and Experimental Therapeutics 6.4 (1915): 417-438. |
https://jpet.aspetjournals.org/content/6/4/417 |
If anyone has an access, it would be great to look at full texts. |
Other relevant papers: |
Gebber, Gerard L., and Robert L. Volle. "Mechanisms involved in ganglionic blockade induced by tetramethylammonium." Journal of Pharmacology and Experimental Therapeutics 152.1 (1966): 18-28. |
https://jpet.aspetjournals.org/content/152/1/18.short |
Another interesting one is |
Wien, R., et al. "The ganglion blocking properties of homologous compounds in the methonium series." British Journal of Pharmacology and Chemotherapy 7.4 (1952): 534. |
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1509303/?page=2 |
While not a TMA, but a more complex molecule - they see increased neural effect with gradual methyl to ethyl replacement. |
Sorry for the long one! |
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: Friday, June 23, 2023 11:48 AM |
To: Labnetwork Mailing List <labnetwork at mtl.mit.edu> |
Subject: Re: [labnetwork] TMAH alternatives |
Hello All, |
Thanks for all your responses regarding potential replacements for TMAH. |
It appears that some folks have been making their own investigations along these lines, and others are interested in doing so. Since some of this work is on-going, the idea was suggested that we create an email list where we can coordinate these efforts. This will be called the TMAH Working Group, so that it can encompass a wide membership, including NNCI member institutions as well as others, including perhaps some industry folks as well. |
As we find out more, we'll keep the main Labnetwork apprised of our progress. |
So, if you have an interest in furthering this work, or would like to share your findings or recommendations, email me at hathaway at cns.fas.harvard.edu, and I'll put you on the mailing list. |
The first notable finding is that Sachem Envure 3330 and Transene SE-33 appear to be the same stuff, i.e. Envure is repackaged in smaller lots for smaller companies and labs by Transene. As Graham at Queens pointed out, Huntsman seems to develop novolac photoresists reasonably well, with some variation in develop time. |
As mentioned previously, the active ingredient in Envure/Transene is TEMAH (triethyl methyl ammonium hydroxide), while Huntsman uses (hydroxyethyl) methyl ammonium hydroxide. With regard to safety, we only have, as yet, whatever the manufacturers say. The marketing info suggests one of the Transene products (SE-33) is around 8x less toxic, while the others may be 15x less toxic. Huntsman just says their stuff is "safer". Clearly, a bit more digging in is called for! |
The initial email for the TMAH Group will go out shortly, |
Thanks, |
Mac Hathaway |
Harvard CNS |
________________________________ |
From: Graham Gibson <gibsong at queensu.ca> |
Sent: Saturday, June 17, 2023 2:42 PM |
To: Hathaway, Malcolm R <hathaway at cns.fas.harvard.edu>; Labnetwork Mailing List <labnetwork at mtl.mit.edu> |
Subject: RE: TMAH alternatives |
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<https://urldefense.proofpoint.com/v2/url?u=http-3A__www.nanofabkingston.ca_&d=DwMFAg&c=WO-RGvefibhHBZq3fL85hQ&r=TEMLD8-VsxCGtcVzmvpT5GFNSczskEKHzW6aYlttmIY&m=OsyPDb0Ur6EvRRta3mwKsTIMksoH8kgvJF4CjMEccxyIPWc8KlY75EEy4r7Mkh_e&s=C1IJR82INSIBlZMD65yCnLorWFHWjaFNg1gJ81DnzVI&e=> |
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? |
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