Earlier quoted context omitted.
This is a very imperfect analogy, but CPUs are typically designed using a high level language like SystemVerilog (equivalent to something like C++ in the software world.) To actually get the CPU manufactured, you have to "compile" it into a binary format that specifies the physical layout of the chip while respecting a set of design rules for whatever process you're targeting. These rules are usually considered highl…
I dream of a world where public libraries have CPU printers. 180nm isn't crazy awful though, is it? That's about 20 years back, so you won't be doing ML, but it's enough to have industry applications and low power general purpose computing.
While you would not want to make a CPU in 180 nm now, or any purely digital circuit, which could be better made with a FPGA, unless you need clock frequencies over 1 GHz, if you want to make any mixed digital-analog circuit with an important analog part, 180 nm can be fine.
Any analog circuit part made in 180 nm will not be much larger than in any up-to-date process, because the dimensions of the analog components are determined by functional requirements, such as noise or maximum current, not by the lithography limits.