Patent ID: 8339605

Claim:
A metrology target for determining a relative shift between two or more successive layers of a substrate comprising: a first structure on a first layer of a substrate, the first structure comprises: four substructures on the first layer each defined by two perpendicular line segments crossing at their midpoints extending in an X-Y direction in a first XY plane, whereby each substructure is located an equal known distance from a center of symmetry of the first structure along the X axis and Y axis in the XY plane; and a second structure on a successive layer to the first layer of the substrate, the second structure comprises: an acquisition substructure and four substructures on the second layer, the four substructures each defined by two perpendicular line segments crossing at their midpoints extending in the X-Y direction in a second XY plane, whereby each substructure is located an equal known distance from a center of symmetry of the second structure along directions 45 degrees from the X axis and Y axis in the XY plane, wherein; the center of symmetry for the first structure and second structure are coincident and a shift from this coincident placement indicating a substrate layer shift; and the first structure and the second structure have 180 degree symmetry.