Patent ID: 7405088
Filing Date: 2008-07-29
Classification: H01L

Abstract:
1. A method for analyzing fail bit maps comprising: inputting positions of failures in wafers; preparing sections on the wafers; calculating feature amounts configured to represent distributions of the failures in the wafers for each of the sections by at least one numerical value; calculating a first numerical value configured to represent a degree of similarity between the feature amounts of the wafers; and detecting another wafer having the first numerical value greater than a predetermined first threshold for each of the wafers, and forming similar wafer groups of the wafers having the distributions of the failures similar to each other, wherein calculating the first numerical value includes at least one of: calculating a first correlation coefficient between the feature amounts of the wafers; performing a Fourier transformation regarding the feature amounts as waveforms and comparing first spectra of the Fourier transformation of the waveforms; and using a maximum entropy method.