System and method of pattern detection for semiconductor wafer map data
OwnerPeter Waksmaninventor
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Abstract
A system and method is described for detecting the presence of spatial non-randomness in semiconductor wafer map data comprised of a computer or embedded processor with the ability to interpret and extract the two-dimensional position of events defined in the data; a set of sub-regions of the wafer; a program for calculating multiple chi-squared values, each testing the null hypothesis that events counted inside a sub-region are random and in proportion to the area of the sub-region; a method for sending the result values to a destination, either inserted into the original data or as a separate result record; and a mechanism for testing the results to see if they satisfy an alarm condition and generating an appropriate response.
Claims15
A system and method for detecting and reporting the presence of non-randomness in wafer data comprising the steps of:
- reading input wafer data from a source
- calculating a chi-squared value for each of a collection of sub-regions, using sub-region relative area ‘a’, within a total region of area 1;
- and using event counts n1 inside the region and n2 outside the region and the formula (where N=n1+n2)
- χ2=[(n1−aN)2/aN]+[(n2−(1−a)N)2/(1−a)N]
- determining if these chi-squared values satisfy a defined alarm condition and generating an appropriate response
- writing chi-squared results as output to a destination.
Dependencies are inferred from the claim text.