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How are 7nm and 14nm mixed? Are they made separately and then... attached together? Isn’t a die made from a single wager “burned” with a single wavelength?

• pacificmint 8y ago
  7nm and 14nm do not refer to the wavelength of the light. They describe the size of the features on the chip (though that is getting increasingly inaccurate). Either way, Zen chips are already multi die chips. For Zen and Zen+ each die has (up to) four cores. Chips with more cores than four contain multiple dies. For Zen 2 they are going to be mixed differently, which is what you are referring to.
  • atq2119 8y ago
    Mostly correct, except Zen (and Zen+, and Zen 2) has eight cores per die. You may have been thinking of core complexes (CCXs), of which there are two on a die, and each CCX has four cores.
• atq2119 8y ago
  You're mixing up a bunch of things. Each wafer, which is the disk on which many dies are produced, is produced using a single technology process. This means that Rome's IO dies (14nm process) are produced on separate wafers from the core dies (7nm process). The wafers are sliced into dies, the dies are tested and binned separately, and sufficiently good dies are then packaged together into a single package that goes into your server's CPU socket. The wavelength of the laser used for the manufacturing is a different story entirely. Pretty much all state-of-the-art photolithography uses 193nm wavelength lasers, and this has been the case for many years. Yes, the wavelength is larger than the size of the features produced with those lasers. There's a lot of magic involved. Since it's getting a bit too much magic, the industry has been trying to upgrade to 13.5nm (extreme ultraviolet) lasers for a long time. They're now starting to be used in actual practice. And EUV lasers are still basically magic, but of a different kind.
  • fipple 8y ago
    Yeah, I guess I never thought about putting multiple dies in one package. How are they wired up anyways?