gambit
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There is the 'yield per wafer' figure. Every new product, including established products but on a new lower node, have a lower yield per wafer figure. If there is 100 dies per wafer, a successful commercial product would require at least %75, or 75 good dies, to sell. This is just a guide, not hard numbers. If I am shopping for a CPU, I would not buy a from a product line that has %50 yield per wafer.
The Economics of Intel Corp.’s Coffee Lake Chip | The Motley Fool
How much will additional cores impact the cost structure of Intel's new desktop chips?
www.fool.com
Now, assuming a constant defect density of 0.2 defects per square millimeter, that same calculator tells us that of the 472 total chips produced per wafer, 372 of them will be usable.
Applying this to the larger hex-core Coffee Lake die, I get 286 good die per wafer for a yield rate of 74.8%
Of course, different products will have different acceptable dies per wafer yield that are considered acceptable to contract. Edge dies are those that are literally at the edge of the wafer are not yielding dies because they are %99 partially created, in other words, incomplete dies, so they are not functional. If there are 100 dies on the wafer but only %10 are good dies, most customers would not contract that product. It means there are serious process flaws. Edge dies are immediately discarded, so why are the rest not functional when they are fully formed dies? So what is wrong with the processes that only %10 of fully formed dies became functional CPU, or DRAM, or NAND, or whatever product? So it is not high defect rate as you alluded but most likely yield per wafer related. Or too low good dies per wafer to be profitable. We do not know.
