alt Hacker NewsMaybe I'm missing something here, doesn't this simply move the precision problem to a different part of manufacturing? Previously you had to be precise with aligning the chips, now you have to be precise with how you put those alignment marks on the chips you want to align. Am I missing something here? Or is it considerably easier to put the marks on the chips with sufficient precision?
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dooglius • 11/07/2024
I would think the alignment marks would be included in the photomasks, so they would be part of the chips themselves
Putting marks on the chip with high precision is much easier; that's done by the same kind of lithographic process that's used for building up all the other layers of the chip, which is generally via exposing a photosensitive layer of material with light through a mask, and they already have ways of keeping those mask layers in alignment.
But aligning multiple chips together is a different process, and while it sounds like they previously had ways to do this via simple optical inspection of those alignment marks, that's less accurate than a holographic alignment using a laser.