Patent ID: 7375809

Claim:
A method of aligning a substrate to an exposure system, the method comprising: disposing a patterned substrate on a stage of an exposure system, the exposure system having an alignment routine including; locating a first point of interest on the patterned substrate, the first point of interest being within a single die of a semiconductor wafer; scanning a first area on the patterned substrate proximate the first point of interest for a first unique feature within the single die; defining a periodicity for the patterned substrate, the periodicity corresponding to the scan area of a raster movement used in locating the first unique feature; locating a second point of interest on the patterned substrate; scanning a second area on the patterned substrate proximate the second point of interest, based on the defined periodicity used in locating the first unique feature, for a second unique feature corresponding to the first unique feature, wherein the first unique feature is saved as an alignment image for use in locating the second unique feature in the second area; gathering alignment data with respect to the patterned substrate from the scanning of the first area on the patterned substrate proximate the first point of interest for the first unique feature and the scanning of the second area on the patterned substrate proximate the second point of interest for the second unique feature corresponding to the first unique feature; and determining substrate position relative to the exposure system from the gathered alignment data.