Delete comment from: Ken Shirriff's blog

CuriousMarc said...

And your damaged chip looks like a typical edge of wafer device. You can see how the photolith pewters out because the photoresist thins out or gets too thick at the edge. The metal layer evaporation also got shadowed at the edge, most likely by rim of the fixture when the wafer was being held upside down in the evaporator.

Jan 30, 2021, 6:34:02 PM

Posted to IBM paperweight teardown: Reverse-engineering 1970s memory chips