An ambitious amateur could probably figure out how to fab a chip of the same complexity in small quantities (using e.g. electron beam techniques), but I think r

An ambitious amateur could probably figure out how to fab a chip of the same complexity in small quantities (using e.g. electron beam techniques), but I think recreating the process faithfully, with the same parameters and variation as the original process, would be almost impossible for anything short of a major corporate R&D project.