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My knowledge of transistors is pretty limited[0]. Does the yield percentage refer to number of successful chips on a substrate or look more at the total number
by godelski 2y ago
My knowledge of transistors is pretty limited[0]. Does the yield percentage refer to number of successful chips on a substrate or look more at the total number of successful transistors? (Or confusing hybrid-term like rain forecasts) I believe your comment implies the latter? So the number of successful processors is quite low? How many failed transistors can you have in a working microprocessor? (Probably not an easy to answer question?)
[0] Am I remembering correctly that this is your area?
- Out_of_Characte 2y agoYield would be the amount of functioning chips. This may be chips, entire packages or even a complexer answere where good chips also need to be below certain leakage. Cores and caches could be disabled and the list of potential yield increasing tooling is always increasing when wafers nowadays costs thousands of dollars.
- notjoemama 2y agoI’ll add chip designers add redundancy. When errors are detected in testing, they can disable sections of the chip by lasering fuses. That allows routing the circuit through a higher quality area. Quality is measured by not only that the circuit produces correct data but also within tolerances of timing and voltage. IIRC RAM is approximately 10% redundant. A good quality chip will use what meets the spec and leave good transistors unused. A poor quality chip will disable bad ones and only use the ones that meet spec.