From the horses mouth: 2/4/2021
Automakers canceled orders due to COVID-19, and foundries switched to other customers.
arstechnica.com
I've been working in a US chip FAB for over twenty years now, and they are not just an assembly-line you can throw together and start printing money with.
1. You use a metric butt-load of electricity, so you need to site the plant where you can lock-in good rates for it. After all these years, it still boggles my mind that we have so many production tools - I'm looking at you, Diffusion and EPI reactors - which IDLE at 700C to 900C.
1a. And have fun if your power isn't reliable. A power "bump" can abort a batch-process Diffusion furnace, and there goes 150 of your wafers into scrap. Watch your bean-counters heads explode every time that happens.
The last two we had - I sh$t you not - were when Facilities was testing the hand-off between our power back-up systems.
Oh, and if it was an LP-CVD tool that was affected, and the chamber got dusted, you also get to eat the lost production time for doing a quartz change, and time to run quals to get the tool back into production. And those pesky batch tools can have a couple of 6 -to- 8-hour processes to run to pass quals - so your affected tools can be down for a day or two.
2. As you are building the plant, you have to maintain/enforce cleanliness protocols so that you can have an acceptable chance of meeting cleanroom requirements required in the functioning FAB.
3. You use all kinds of industrial gases & chemicals, so you need to site the plant where you can have reliable supply of bulk materials - so if you don't have Praxair, Air Liquide, etc nearby your costs are going to be higher. e.g. My employer has a deal with our supplier that has a Nitrogen concentrator installed & running on-site, and the supplier gets to sell any excess N2 to their other nearby customers.
4. Clean water. We use tons of DI water, so you have to build that supply system into .....
Aw screw it. I don't feel like writing a wall of text.
There is a lot going on in running a FAB, even after you've paid out the nose to build a huge cleanroom space, run all the needed support gases and fluids to each tool, and paid out the nose to have expensive production tools installed and processes qualified for production.
Hazardous materials out the wazoo... most every acid you've ever heard of... Hydroflouric (HF) is my personal fave...
Chlorine (in its' own 'bunker'), Hydrogen, Silane (pyrophoric!), - scared me when we got a new tool using Nitric Oxide (NO) a few years ago, and I overheard a couple of Process guys joking about sneaking back behind the tool to huff a little - because they were thinking it was Nitrous Oxide (NO2). I interrupted them to say they were mistaken, and huffing on any NO would be the last thing they would ever do...
Hell, just DI is dangerous when there are ignorant workers around. e.g I had an operator in CMP who had to be convinced that it was bad for them to be refilling their water bottle with DI from a sink in the FAB ...
TL
R So yeah, a wall of text anyway... Fabs are expensive to build, staff, and run - and they only make economic sense - due to all the fixed costs for electricity, DI water, and gases (N2) which are required even when the FAB is "idle" - to be running 24/7/365
