semiconductor folks! I've seen a lot of talking heads repeat the claim that "a helium shortage is bad for chip production", never substantiated with useful information. do any of you know:
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
macnamara on bsky is the first person to give a credible and comprehensive primary source for total He usage by a semiconductor facility in this report
Each advanced semiconductor facility consumes approximately 2-4 million cubic feet of helium annually for various manufacturing processes, including ion implantation, chemical vapor deposition, and plasma etching operations.
this is a range of 56000-113000 cubic meters of helium per year, or 155-310 cubic meters per day
@whitequark UHV systems will typically have a cryopump. This is a closed cycle helium system and although they do break and need to be recharged occasionally it's much less than a cylinder per year.
Sputter systems are a common place to find these
@whitequark I think a large part of the panic we periodically see over semiconductor consumables exists only because analysts and tech executives have convinced themselves that fabs are these super high tech automated facilities, when in fact they are massively labour intensive to operate
They think they're like data centers where you can staff them with like 3 security guards one tech and a few remote hands when in actuality you need a massive team of highly skilled people working in three shifts around the clock
@whitequark That's a good question ye.
Maybe some of the vapor deposition processes?
@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 Oh. Yeah. That could be a use.
@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.
@Sobex @whitequark
If we do a search for Helium Semiconductor, we will find lots of reliable sources discussing the effect of Helium shortage on the semiconductor industry and MRI equipment.
E.g.,
https://www.semiconductors.org/wp-content/uploads/2023/03/SIA-Comments-to-USGS-Request-for-Comment-on-Helium-Supply-Risks-3_16_23.pdf
https://www.ibselectronics.com/resources/news/helium-supply-disruption-semiconductor-manufacturing-risk/
https://www.frost.com/growth-opportunity-news/industrial/helium-as-the-new-chokepoint-in-semiconductor-supply-chain-can-singapore-turn-adversity-into-opportunity/
@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 when I worked in the clean room, the most significant use of helium was to purge the vacuum of sputtering machines. We were not particularly frugal, and there was no thought of recovery.
I think it's reasonable to worry about the sustainability of casually blowing it into space while the only affordable source is in natural gas pockets.
For reference, for one wafer, I'd waste about 500l of helium on average (rough guess).
@psistarpsiii you'd think that, but when recovery is more expensive than the new stuff, capitalism sez no.
@whitequark yup, but if we could burn it to the ground in favor of something more kind and intelligent, we could avoid a lot of waste and suffering, so no objections to that from my side 🙇♀️
@whitequark my understanding is that the extreme low temp refrigeration was the main use of helium. Getting magnets to superconducting temperatures for MRI machines and such
But I'm not sure how it would be used for semiconductor production
@whitequark the bulk (90%+) of the helium reserve was sold off years ago; the inventory entered the ordinary market for helium and was used for all the things anybody uses helium for, and the remainder was sold with the land and facilities to an industrial gas supplier (Messer) in 2021
helium is primarily obtained as a byproduct of natural gas extraction, and the US is now the leading producer of both gas and helium; the reserve was wound down because the US is no longer dependent on helium imports, and produces vastly in excess of domestic demand
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