Patent ID: 9182680
Filing Date: 2015-11-10
Classification: G01B,G01N,G03F,H01L,Y10S

Abstract:
1. A semiconductor target for determining a relative shift between two or more successive layers of a substrate, the target comprising: a plurality of first structures formed in a first layer with a first center of symmetry (COS); and a plurality of second structures formed in a second layer with a second COS, wherein the first and second structures have a particular rotational symmetry, without having a second rotational symmetry, with respect to the first and second COS, respectively, wherein the first COS and the second COS correspond to an overlay error between the first and second structures, and wherein the first and second structures have a 180° rotational symmetry, without having a second different rotational symmetry, with respect to the first and second COS, respectively.