Stepper and scanner new exposure sequence with intra-field correction
 A method and system are provided for determining the degree of overlay misregistration when exposing a semiconductor wafer having a center and a periphery comprises the following steps. Expose the wafer with a scan in a sequence from the center of the wafer to the periphery. Select dies on the periphery of a wafer for measurement which represent a maximum degree of distortion, and employ a correction algorithm for calculating an intrafield reduction ratio to minimize heat expansion. 
Taiwan Semiconductor Manufacturing Company
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Meng Chun
Li