addition

The passage around this formula

The second ceiling is statistical and softer, but it bites earlier. Defects arrive on a wafer at some density, and the probability that a given die contains none of them falls as its area grows. Feng and Ma, in the cost model they published for multi-chiplet architectures, use the negative binomial form $Y(A) = \left(1 + \frac{D_0 A}{c}\right)^{-c}$. with defect density $D_0$ , die area A , and a clustering parameter c that captures the fact that defects are not independently scattered [ 2 ] . The exact parameters matter less than the shape. Yield falls monotonically with area, so cost per good die rises faster than area, and past some size the marginal square millimetre costs more than the function printed on it is…

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