semiconductor folks!

[ben@s.djehuti.com]

@krans @whitequark I can at least answer the last question. https://en.wikipedia.org/wiki/National_Helium_Reserve

[sobex@social.sciences.re]

@whitequark On bsky, the first thing in my TL seems to be there https://fosstodon.org/@AkaSci/116273165320321185

[whitequark@social.treehouse.systems]

@ben @krans I did read the Wikipedia page, obviously. I'm asking the question because I'm interested in non-public information industry insiders are usually aware of

[lixou@hachyderm.io]

@whitequark the only thing where I heard chip and helium in one sentence was an announcement from a norwegian company who want to replace EUV with helium atoms for smaller prints. But that surely isn't meant lol

[ben@s.djehuti.com]

@whitequark @krans I was sure the answer was going to be that it got used for an epic white house slumber party

[gsuberland@chaos.social]

@whitequark I have never heard a good explanation either.

[dalias@hachyderm.io]

@whitequark The US strategic reserve was sold dirt cheap to capitalist parasites.

[whitequark@social.treehouse.systems]

@gsuberland apparently the primary use, or at least one of the primary uses, is wafer and lens cooling during high temperature processing (so it's used as a heat transfer fluid and mostly recovered); there may also be uses of it as carrier gas or purge gas; I haven't got any numbers still

[whitequark@social.treehouse.systems]

@dalias I know that, but not what said parasites do with it now, which is the part that interests me

[be_far@social.treehouse.systems]

@whitequark helium is non-reactive, so it’s used as a carrier gas and a chamber control gas (fill the chamber with it and flow your chemical vapor deposition gases into that environment). Different gases have different effects on the temperature control of the chamber for different materials’ growth processes. As a carrier gas I believe helium has the most use in Si-doping.

A few paragraphs on helium’s thermal properties in https://semiengineering.com/using-less-helium-in-semiconductor-manufacturing/

[whitequark@social.treehouse.systems]

@be_far thanks. I have some background in vacuum systems so this makes a lot of sense. do you know the ballpark number for how much helium is used, after accounting for reclamation?

[riley@toot.cat]

@whitequark FWIW, my hunch is, if chipmaking is affected by helium deficit, the troubles would be more likely to hit R&D and possibly the construction of new foundries than ongoing manufacturing processes. Cryocrystallography is a thing in materials science research, and while it used to largely get by with liquid nitrogen, the bleeding^W chattering edge of new research has been shifting steadily coldwards.

[whitequark@social.treehouse.systems]

from some discussion and research, it seems like one of the major uses is in ESC/BSG wafer clamp devices (https://csmantech.org/wp-content/acfrcwduploads/field_5e8cddf5ddd10/post_6573/15.3_Characterization_of_Electrostatic_Chuck.pdf) where flow of helium is less than 20 sccm per chuck.

this represents about 2 micrograms of helium per second per chuck, which i'm not too concerned about. there are of course some other applications that may consume more helium

[whitequark@social.treehouse.systems]

@riley yea that's reasonable

[riley@toot.cat]

@Hemera As far as I know, all currently used cold vapour deposition techniques of relevance to (mainstream) chip-making can be done at liquid nitrogen temperature or higher. Quantum computer research might have uses for colder ones. It's not impossible that NSA could be using helium-requiring chips in large numbers, and their supplier(s) would have trouble without helium, but I don't know of solid leaks positively affirming such, so far.

@whitequark

[whitequark@social.treehouse.systems]

@riley @Hemera consider that helium is also sometimes used as carrier or purge gas (in quantities I'd very much like to know about)

[be_far@social.treehouse.systems]

@whitequark the one number I’ve ever seen (couldn’t ever find a source, everyone just repeats it) is that one advanced TSMC fab uses 500,000 cubic meters of helium a year. If it’s used as a purge gas like you mentioned in another comment I imagine it’s very low reclamation but I don’t know if that number takes reclamation into account (even if it’s not made up).

[riley@toot.cat]

@whitequark Oh. Yeah. That could be a use.

@Hemera

[sobex@social.sciences.re]

@whitequark @riley @Hemera Purge gas is the explanation I had seen, and I had heard also that EUV machines needed it (though apparently, people in this thread are suggesting hydrogen is used ?)

I think it would make sense to have a non-reactive gas atmosphere, though.

[whitequark@social.treehouse.systems]

@be_far yeah it's infuriating how often someone just pulls a figure out of who knows where and then everyone else repeats it