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The spin coating process that applies etch resist also favors round wafers but if they've figured that part out, it's a win because their precision positioning
by throwup238 2y ago
The spin coating process that applies etch resist also favors round wafers but if they've figured that part out, it's a win because their precision positioning equipment is limited to a square X/Y stage. With round wafers, they lose quite a bit of that space and the wafers are so cheap that wasting some edges isn't a big deal compared to the reduced overhead per chip.
- adolph 2y agoBy squaring the circle, they gain by holding less non-addressable space in the etching step?
- LeifCarrotson 2y agoWhy is the precision positioning equipment limited to a square stage? Or is it actually a rectangular stage? Couldn't they use an r-theta circular positioning system instead of linear? Their optics are fundamentally circular constraints, seems like that should drive everything else to a circle.