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Equation 21 · Part 4 · Patterning at the Limit: What Actually Happens When a Chip Is Manufactured

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Y(2S)=Y(S)2Y(2S) = Y(S)^2
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What this part means

A raised number can be a power. When it is a label or bound, it selects a case or the upper limit of a sum; the formula’s structure distinguishes these uses.

Its job in the formula

A raised mark can be a power or an index. Its position and the surrounding notation determine which.

The passage around this formula

The Poisson limit exposes the die-area relationship in one line. Because the exponent is linear in area, doubling die area squares the yield: Y(2S) = Y(S)^2 . A part yielding 80 per cent at one size yields 64 per cent at twice the size and about 41 per cent at four times. Yield does not decline with area; it decays geometrically. Finite c softens this — real defects cluster, clustered defects waste fewer dies than scattered ones, and this is precisely why the industry prefers the negative binomial form over Poisson, which systematically understates large-die yield.

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Learn the underlying idea

An exponent tells how a base is used in multiplication. In x³, x is the base and 3 is the exponent: x³ = x × x × x.

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Sources cited in the article section

These citations provide research context; check each source for the exact claim it supports.