Re:Awesome! (Score 2, Interesting)

Does anyone know what the technology was for the 4004? (Is that metal-gate, with double-metal, or polysilicon gate with single-poly, single-metal?)

Well, I do look at photomask stacks as part of my job from time to time as a process integration engineer (mask bugs do make it past design rule checking and tapeout sometimes) but I will start with a disclaimer that this chip and process was designed before I was alive.

It looks from the composite drawing that this is a single poly/single metal/self aligned doped poly/source/drain. That should have existed at the time and to my knowledge no metal gate process has been in wide use because of manufacturability and performance problems. It looks like the red is poly (gates and lines), blue metal, and the green is the source/drain/poly doping diffusion. Whether that was done with implantation or glass doping I'm not sure (again before my time, implant was coming into use but glass doping was much cheaper, if not as controllable). It is kind of nice to see such a simple design.