Giebels2609 wrote:
Tor wrote:
You'll also need masks for the 6502 etc.. I don't know if they are even available - visual6502 could have used the masks instead of having to de-cap a 6502 if so, maybe. If they are available (Commodore and MOS aren't around anymore) they would have to be licensed anyway.
Nope, I'm currently making preparations in CAD software for maikng new masks.
Try CLEwin. Its cheap, can handle many layers and for a 3500 transistor design you can probably do it manually within a couple of weeks. The only problem with that is debugging which becomes a manual thing.
For a more professional approach I would do the design in VHDL or Verilog (both of which have numerous cores available). Ask one of the people that has already made a core to license it. You can then translate that into a transistor-level design without even seeing a mask.
A small fab isn't very costly to set up, but it can become quite labor-intensive without the correct investments. I have once put up an in-house cleanroom with both litography, metallization and characterization equipment (it was for other things, not transistors). Using old equipment makes sense in the short-term, but for long-term you also need to consider maintenance, repair, engineering hours and having enough spare-parts for the machines to function. With 10 or 20 machines running, its enought that one of them stops working and your fabulous fab is down for hours or days. Fab down=no income.
A simpler option is to be a fabless design house. It means that you submit your design to one of the service companies of TSMC or alike. They don't want to talk to you directly, so you have to go through a service/design company that is already a customer of one of the large manufacturers (as TSMC is). These offer different ways to make prototypes or production runs, the latter requiring your own mask set (which will cost >100K USD for 150mm wafers). But with production runs you can make 65C02's for much less than in a small fab. Even a few thousand devices will be cheaper. Heck, they may even help you to put up a NMOS process if you really want that.
Anyway, good luck!