> you get more chips per wafer but if the machines cost 10x as much, let's say, then it's not necessarily worth it That's sort of the point I'm making here: th

> you get more chips per wafer but if the machines cost 10x as much, let's say, then it's not necessarily worth it That's sort of the point I'm making here: there is fundamentally no real cost differential unless you go really far back to when the equipment was really rudimentary. The old machines are cheap because they're used. If there was someone still manufacturing them, their cost would not be greatly different from modern equipment. The best analogy I can make is an old car. Being older doesn't mean it's a whole lot cheaper to manufacture. Maybe a little -- no fancy computers or direct fuel injection -- but you lose that benefit really fast because of the shitty fuel economy. Most of the modern equipment is "backward compatible"; modern CVD or PVD or CMP or etch equipment would work fine at any trailing node, with the exception of the fact that they would work only with 300mm wafers (which is actually an added cost efficiency). The biggest difference I could imagine is with litho equipment. 193nm immersion is expensive and EUV is even more outrageous. You could probably use old non-immersion litho technology with modern multiple patterning instead.