On Murphy's yield integral (IC manufacture)

The technique for estimating integrated circuit manufacturing yields by means of a compounding technique originally described by B.T. Murphy (1964) is discussed. The author derives and describes the related yield formula and discusses the reason for its eventual shortcomings and demise. It was assumed that the use of Gaussian distribution as a model for the variation in defect densities requires the use of a triangular approximation. However, such an approximation is not necessary. It is shown that an exact solution is possible. The resulting yield formula has been used in the industry for a short time, but has been superseded by use of the negative binomial yield model, which is easier to manipulate and in better agreement with actual data.<
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