FAB Fabrication plant. These are enormous clean room plants for growing the silicon wafers. (Start video at 8:50)
They produce "chips" in particular MCU or Micro Controller Units. Which are not quite the same as a CPU or Central Processing Unit on a PC
Technically the processors on the M1 Mac are MCUs not CPUs The other one is GPU or Graphics Processing Unit which is a specialist MCU/CPU similar to a DSP (Digital Signal Processing Unit)
The shortage was due to flooding in several major fabs in Asia, far bigger than the one in the video, due to freak weather. It took a couple of years to rectify. Then you had the backlog of supply to get through. This was just getting back online when COVID hit. As you will see in the video, they are huge clean rooms where the few people wear full suite, masks, hair covers, eye protection as normal working procedures. These places have filtered forced air and are cleaner than any hospital operating theatre. Also, as staff don't tend to work closely with other people, they were not really affected by COVID. When COVID hit, I think they kept shifts in isolated dorms rather than going home.
The electronics production for PCBs (the circuit boards) is 99% automated, once the chips came back online there was little problem with production during COVID. Vehicle production was affected. Whist much is automated final assembly does require people in close proximity, The problem was the chip shortage and COVID overlapped a bit. So you had cars held up with the chip shortages, though some of the problems were due to politics (commercial, not government) in the industry. Then COVID.
At the time, I was a member of this https://aesin.org.uk/ as I did embedded critical systems. So I saw it from the inside, talking to the Tier 1's and the supply chain.
I retired in 2023 closing the company