Patent ID: 7541201
Filing Date: 2009-06-02
Classification: G01B,G01N,G03F,H01L,Y10S

Abstract:
1. A method for determining the relative shift between two or more successive layers or between two or more separately generated patterns on a single layer, the method comprising: acquiring a first image of a plurality of first structures that are designed to have a plurality of same or known offset first centers of symmetry (COS) or first lines of symmetry (LOS), the first structures comprising two or more successive layers or two or more separately generated patterns, and being arranged to determine the relative shift in an x direction between the two or more layers or patterns of the first structures by analyzing an image of the first structures; and acquiring a first image of a plurality of second structures that are designed to have a plurality of same or known offset second COS or second LOS, the second structures comprising two or more successive layers or two or more separately generated patterns, and being arranged to determine the relative shift in an y direction between the two or more layers or patterns of the second structures by analyzing an image of the second structures, wherein the first COS or LOS has a different location than the second COS or LOS; analyzing the first image of the first structures' COS to determine whether the first structures have a shift in the x direction that is out of specification; and analyzing the second image of the second structures' COS to determine whether the second structures have a shift in the y direction that is out of specification.