Comment by throwup238
13 hours ago
The big problem is purity. Fabs use grade 5 and 6 helium where contaminants are 1-10 parts per billion. The infrastructure to get it that pure becomes very specialized and any time the helium goes through a process it picks up so much contamination that recycling it would require the entire purifying and quality control infrastructure for pressure or temperature swing adsorption.
Some fabs are starting to reuse helium in downstream processes but there’s only so much they can do without expanding their core competency into yet another complex chemical manufacturing process.
MRI machines don’t need high purity helium and the contamination doesn’t “gunk up” all the tools so it’s not an issue to recycle it there.
Now I'm imagining a procedural cop show where they bust an illegal helium dealer, and one of the cops takes a huff to gauge what they're dealing with, and then squeaks out "that's the good stuff".
https://www.youtube.com/watch?v=9aIDxHesKyU
> The infrastructure to get it that pure becomes very specialized
I think some of the most advanced fab infrastructure is the ultra pure water system. Water becomes quite aggressive chemically when it has no dissolved ions in it. You have to use exotic or highly processed materials simply to transport it around. If the factory didn't need such massive quantities of it, trucking it in would likely be preferable.
I guess you watch asianometry?
https://www.youtube.com/watch?v=C3RzODSR3gk
Ultrahigh density polyethylene isn't that exotic.
From the article I thought the helium was used mostly for cooling (where I imagine the purity wouldn't be that important)
But what other processes do the fabs use the helium for then?
It is used a lot for cooling but in many systems its used without a classical heat exchangers where the helium is isolated from the workpiece.
Helium is pumped beneath the wafer to keep it cool so any impurities can leak through the chuck seal into the chamber above and disrupt the process. It’s also very precisely controlled so impurities change the uniformity of the thermal conductivity of the gas, creating hot spots on the wafer.
In EUV it’s used to both to cool the optics and as a buffer gas to manage debris from the plasma so any contaminants can deposit on the optics. At 13.5nm even a single layer of hydrocarbon molecules can create problems and the light bounces many times between mirrors so the error compounds.
There are many places where helium doesn’t have to be as pure but contamination events and surprise maintenance are so expensive that it’s not worth the extra savings (or the risk of mislabling and using dirty helium in the sensitive parts).
Thanks a lot for the info. Yeah, it makes sense that if you need pure helium anyway, you probably wouldn't create an entire second supply chain for impure helium.
Do we have a process to make new helium from hydrogen?
If you want to make new helium, it's far easier to go the other way.
You just need quite a bit of Polonium, Thorium or Radon. Put it in a pool - and then wait a while. You just gotta collect what bubbles to the surface.
If you come up with a process to do that efficiently, the helium will be a lovely bonus but not remotely the most important result. :D
Yeah, but it gets quite warm
We usually take it from natural gas deposits instead.
Nuclear fusion?