Definition
Semiconductor yield is the percentage of dies on a finished wafer that function correctly and meet specification. Because a wafer's processing cost is largely fixed, yield is the single biggest lever on the cost of each working chip: if half the dies fail, every good die effectively pays for a bad one. Yield is therefore central to the economics of every mining ASIC.
What drives yield
Random manufacturing defects are scattered across a wafer at some average rate, known as the defect density (often written D0). A larger die presents a bigger target, so it is statistically more likely to contain at least one fatal defect. Yield models such as the Poisson (Murphy) model combine die area and defect density to estimate how many dies survive. As an illustration, a 300 mm wafer carrying 100 mm-squared dies at a defect density of 0.5 per cm-squared yields on the order of several hundred good dies.
Why miners should care
Early in a new node's life, yields are low and chips are scarce and expensive; as the foundry refines its process, yield climbs and cost per chip falls. This learning curve is part of why miner prices for a given generation tend to soften over time. Some designs even tolerate a few dead hashing cores per die, recovering chips that would otherwise be scrapped and effectively raising usable yield.
Yield depends heavily on die area and on the maturity of the process node, and salvaged partially-good dies feed into chip binning.
See generational cadence in the ASIC release timeline.
In Simple Terms
Semiconductor yield is the percentage of dies on a finished wafer that function correctly and meet specification. Because a wafer’s processing cost is largely fixed,…