Patent ID: 8219351
Filing Date: 2012-07-10
Classification: B07C,G01R,G05B,Y02P

Abstract:
1. A non-transitory computer readable medium containing computer instructions stored therein for causing a computer processor to perform a method for aligning wafers processed in a semiconductor fabrication facility, comprising: identifying on a first wafer a first arrangement of dies having a common functionality level; assigning a first alignment signature to the first wafer based on the first arrangement, wherein assigning the first alignment signature to the first wafer comprises: applying a zone map to the first wafer, the zone map having a number of zones arranged along at least one axis of radial symmetry; rotating the first wafer or zone map, with respect to one another, through a number of rotational orientations and storing a vector at each rotational orientation; calculating a first set of scalar values, each scalar value of the first set calculated at a different rotational orientation of a vector relative to the first wafer; and analyzing the first set of scalar values to determine the first alignment signature; identifying on a second wafer a second arrangement of dies having the common functionality level; assigning a second alignment signature to the second wafer based on the second arrangement; comparing the first alignment signature to the second alignment signature; and selectively aligning the first and second wafers based on a result of the comparison.