Patent ID: 7868473

Claim:
A wafer capable of being used for alignment in a stepper, said wafer comprising: a substrate; multiple interconnecting layers of deposited material on the substrate, the multiple interconnecting layers configured to form integrated circuits; a target, said target having a solid spine in one direction and having first and second pluralities of fingers coupled to, and configured to extend perpendicular from, an axis of said spine, the first plurality of fingers configured to extend from a first side of the spine that is opposite from a second side of the spine from which the second plurality of fingers extend, said first and second pluralities of fingers being arranged in a pattern such that the first plurality of fingers is symmetrical with the second plurality of fingers about the axis of the spine and the fingers of the first plurality having gaps between each other and the fingers of the second plurality having gaps between each other, the solid spine and the first and second pluralities of fingers formed from the same type of material and arranged to reflect an incident signal with maximum intensity at one or more maxima points indicative of a centroid of the target.