Here’s a guy named Sam Zeloof <https://arstechnica.com/information-technology/2022/01/this-22-year-old-builds-chips-in-his-parents-garage/> who has been using cast-off equipment from bygone eras to put together his own chip fab. He made his first chip (an op-amp) just about four years ago; it had just six transistors. His second one (more proof of concept of the manufacturing process) had 1200 transistors. He has made a bunch of them, testing each one by hand. He is currently working on his third design, in a plan to get to a full working microprocessor.