3 ms·

Replacement corners in case one of the full-size dies in the middle cracks during dicing.

• MayeulC 6y ago
  I know you re probably joking, but please mind Poe's law. For the uninitiated, yeah, some dies can die during dicing. But I think you'd have trouble finding the cracks, and then it's just infeasible to precisely cut both halves where they would need to be cut, then reattach them. The issues would be the cut thickness, not damaging the circuits near it, precisely aligning the circuits, and then electrically connecting the circuits. Alignment is probably the hardest part, we can barely do it for flip-chip wafers/silicon interposers on the order of the µm, imagine doing it at less than 7nm, which is the transistor pitch here.
  • ohazi 6y ago
    Yes, I was joking. :-) I think they do sometimes put test features in the corners if there's space. The electrical properties of the die can vary in interesting ways [1], but the edges are usually worse than the center. [1] https://www.google.com/search?tbm=isch&q=wafer+defect+pattern https://www.google.com/search?tbm=isch&q=wafer+defect+patter...
• jacquesm 6y ago
  Bull. Everybody knows that is because they've been cutting corners like it was crunchtime at the circle factory.