Patent ID: 7456966

Claim:
A system of alignment marks formed on a substrate, the substrate to be used in a photolithographic system having first and second alignment signal sources, each having a width Z, and signal detectors, the alignment marks comprising: a first region configured to provide a first signal to the first signal detector in response to the first alignment signal source having a width Z; and a second region configured to provide a second signal to the second signal detector in response to the second alignment signal source having a width Z, wherein the first signal determines multiple first coordinates of an aligned position of the substrate, the second signal determines multiple second coordinates of an aligned position of the substrate, and the substrate is in a coarse aligned position with the photolithographic system when one of the multiple first coordinates and one of the multiple second coordinates correspond to a maximum received signal strength at the first signal detector and the second signal detector, respectively, wherein the first region and the second region are an X mark diffraction pattern and a Y mark diffraction pattern, respectively, wherein the X mark diffraction pattern further comprises a segment of a Y mark in the X mark and the Y mark diffraction pattern further comprises a segment of an X mark in the Y mark, wherein a segment of a Y mark and a segment of the X mark are removed, wherein each segment removed corresponds to regions of the X mark and Y mark that cause false alignments, wherein an approximate center of a Y mark in the X mark is determined from the width Z of the first alignment signal source and the maximum received signal strength at the first signal detector, and wherein an approximate center of the X mark in the Y mark is determined from a width Z of the second alignment signal source and the maximum received signal strength at the second signal detector, wherein, when the width Z of the first alignment signal source and the second alignment signal source equals a width W of the X mark and the Y mark, respectively, single points of the maximum received signal strengths indicates an exact location of the center of each the X mark and the Y mark.