Comment by aeonik

While it's not "easy", I was surprised to learn recently that DIY microprocessors are far more accessible than I thought.

Here is BreakingTaps fabricating home made chips, he has a fair bit of equipment though

https://youtu.be/RuVS7MsQk4Y?si=c8PH-FMfcfWLJLiG

There a a few different techniques that can be used. Most of the lithography techniques use Hydrofluoric Acid, but if you are okay with slower build times you can etch the circuits directly with Ion beams or Electron Beams.

But the short story is you need an overhead projector, a microscope, and a few gnarly chemicals. Otherwise fairly straightforward.