4 ms·

Anyone know how much that would cost roughly? Wondering if they had a big reject bin that needed to be disposed of.

andreareina 5y ago
Guessing that the cost for a wafer at a state-of-the-art process has gone up over the years but not that much, in the vicinity of ~$10,000? https://twitter.com/chiakokhua/status/1306437988801486848 https://twitter.com/chiakokhua/status/1306437988801486848 sourced from https://cset.georgetown.edu/wp-content/uploads/AI-Chips%E2%80%94What-They-Are-and-Why-They-Matter.pdf https://cset.georgetown.edu/wp-content/uploads/AI-Chips%E2%8... p45
- bostonsre 5y ago
  Pretty pricey for a plaque.. either they really liked him or they had some rejects I would guess.
  - marcan_42 5y ago
    They always have rejects. Actually, that's almost certainly an unfinished wafer. Modern flip chips don't look like that finished - you have an array of pads and power distribution covering all the cool features. I think there's a good chance that wafer doesn't have any metal layers, or only M1 at most. It looks the same as the chips I've delayered and removed all or almost all of the metal layers from. For example, here's a shot of the Wii's GPU with the metal layers scraped off: https://marcan.st/transf/hollywood_die.jpg https://marcan.st/transf/hollywood_die.jpg
- bowmessage 5y ago
  It was always rumored around the FAB that dropping a case of wafers was akin to totaling a Ferrari. Maybe ~20 wafers in a case, so this math checks out!
- qsmi 5y ago
  It depends, is the wafer passing or failing the manufacturing tests? This is an important consideration.
  - monocasa 5y ago
    The manufacturing pipeline is generally pretty long too, and you can stop wafers midflight if you're just going to throw them out anyway. So for instance, if you have some B0 wafers that have enough metal layers that you couldn't easily change them into B1 wafers half way through the process, you might end up with it being cheaper to end up with unusable wafers for plaques and what have you. The fab is generally happy to have the extra capacity even for tail end of the design. There's generally some cheap customers that'll slot in wherever there's gaps.

Guessing that the cost for a wafer at a state-of-the-art process has gone up over the years but not that much, in the vicinity of ~$10,000? https://twitter.com/chiakokhua/status/1306437988801486848 https://twitter.com/chiakokhua/status/1306437988801486848 sourced from https://cset.georgetown.edu/wp-content/uploads/AI-Chips%E2%80%94What-They-Are-and-Why-They-Matter.pdf https://cset.georgetown.edu/wp-content/uploads/AI-Chips%E2%8... p45

bostonsre 5y ago
Pretty pricey for a plaque.. either they really liked him or they had some rejects I would guess.
- marcan_42 5y ago
  They always have rejects. Actually, that's almost certainly an unfinished wafer. Modern flip chips don't look like that finished - you have an array of pads and power distribution covering all the cool features. I think there's a good chance that wafer doesn't have any metal layers, or only M1 at most. It looks the same as the chips I've delayered and removed all or almost all of the metal layers from. For example, here's a shot of the Wii's GPU with the metal layers scraped off: https://marcan.st/transf/hollywood_die.jpg https://marcan.st/transf/hollywood_die.jpg
bowmessage 5y ago
It was always rumored around the FAB that dropping a case of wafers was akin to totaling a Ferrari. Maybe ~20 wafers in a case, so this math checks out!
qsmi 5y ago
It depends, is the wafer passing or failing the manufacturing tests? This is an important consideration.
- monocasa 5y ago
  The manufacturing pipeline is generally pretty long too, and you can stop wafers midflight if you're just going to throw them out anyway. So for instance, if you have some B0 wafers that have enough metal layers that you couldn't easily change them into B1 wafers half way through the process, you might end up with it being cheaper to end up with unusable wafers for plaques and what have you. The fab is generally happy to have the extra capacity even for tail end of the design. There's generally some cheap customers that'll slot in wherever there's gaps.