Semiconductor wafers are circular, and usually they are divided into squares or rectangles. However it's more efficient to pack triangles into circles than it is rectangles, so less wafer area would be wasted. Unlike hexagons, the lines in a triangular tiling extend to infinity, so the saw would be able to pass all the way through the die without stopping. Plus, some packages like SOT-23 are (if you squint) kinda triangular already. Is there any reason I haven't been able to find anything about triangular dicing of wafers?
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1\$\begingroup\$ Not a full answer, but presumably because most things in ICs are rectangles (or maybe 45 degrees if you're feeling adventurous), so your fill density of circuitry in the triangle wouldn't be very good. \$\endgroup\$– Tom CarpenterCommented Sep 8, 2021 at 20:03
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3\$\begingroup\$ Does this answer your question? If silicon wafers can only be made round, why are the chips we make not hexagons instead of squares to cover the edges more efficiently? \$\endgroup\$– Elliot AldersonCommented Sep 8, 2021 at 20:32
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\$\begingroup\$ Sharper corners would result in more stress at the corners of the die which could result in failure of the IC. Triangles also have a larger perimeter compared to their area making such a shape area inefficient and the IC more expensive. \$\endgroup\$– BimpelrekkieCommented Sep 8, 2021 at 20:37
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\$\begingroup\$ youtube.com/watch?v=GzHk1PpFAUg; and besides dies derived at the edges have lower yield and more defects and there is no point in maximixing at the edges. At the packaging stage how would a triangle fit in a rectanglular or a square package? \$\endgroup\$– SyedCommented Sep 8, 2021 at 20:47
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2\$\begingroup\$ The reason this isn't done is because (A) new packaging infrastructure is super costly to develop, and (B) applications that require aggressively minimizing space, do away with the IC package altogether and just mount the bare silicon die on the PCB, so there's no advantage to using unusual shaped dice. See electronics.stackexchange.com/questions/9137/… \$\endgroup\$– MarkUCommented Sep 8, 2021 at 23:43
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Semiconductor crystals used in processing are usually (100) orientation, and their "easy cleave" crystal planes = nice straight cleave over whole wafer, are orthogonal, so it is not possible to apply cleaving and get triangles. Only bars, which then are cleaved into dies.
