Recently, there have been several youtube vids (example) talking about how modern CPUs are manufactured. Basically, it's a complex nightmare of dropping molten tin and lighting it with light, which produces a plasma light that does the proper etching (Edit: oops, etching is actually a chemical process after photolithography). However there is also a photomask produced in an entirely different process.
These manufacturings are very complex and I do not understand them much at all. What I'm curious about right now, is how old processors were made (70s and early 80s).
Something like the 6502 is a prime example. Today it is very cheap, but when it came out it was still extraordinarily cheap relative to other processors available.
How was it manufactured? I really want to know if it was basically the exact same process, just scaled down with much bigger transistor sizes---or something entirely different.