Wafer yield prediction by the Mahalanobis-Taguchi system

摘要

The distribution of yield from the production lines is concentrated at a high-yield area and tapers down to the lower-yield area. Production management would find it useful if the yield of individual wafers could be forecast. The yield is determined by the variability of electrical characteristics and dust. In this study, only the variability of electrical characteristics was discussed. One product was selected for study, and a Mahalanobis space was constructed from the wafers that had high yields. The Mahalanobis distances of various wafers ware calculated in order to study the relationship between yield and distance.