Method for analyzing fail bit maps of waters and apparatus therefor
First Claim
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.
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Abstract
A failure analysis method according to the invention includes inputting the positions of failures in multiple wafers of an input device; preparing multiple sections in the multiple wafers; calculating feature amounts, which are represented by at least one numerical value representing a distribution of the failures in the multiple wafers, for each of the multiple sections; and representing by a first numerical value, the degree of similarity between the multiple wafers in terms of the feature amounts. Subsequently, the method includes detecting another wafer, which has the first numerical value greater than a predetermined first threshold, for each of the multiple wafers and forming a similar wafer group of multiple wafers with similar distributions of the failures.
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Citations
15 Claims
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1. A method for analyzing fail bit maps comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification