SCANNER AND METHOD FOR PERFORMING EXPOSURE PROCESS ON WAFER

摘要

A scanner and a method for performing an exposure process through a photomask on a wafer are provided. The exposure process includes an alignment step and an exposure step. The method includes the steps of moving a wafer table to align the wafer with an alignment apparatus, wherein the wafer table includes at least one chuck hole to attach the wafer to the wafer table by vacuum chucking, detecting an actual position of each of a plurality of alignment marks on the wafer, calculating an index value based on a difference between a predicted position and the actual position of each alignment mark, adjusting a vacuum pressure of the at least one chuck hole in the alignment step when the index value is larger than a first threshold value, and finishing the exposure process when the index value is smaller than or equal to the first threshold value.

主权项

1. A scanner for performing an exposure process through a photomask on a wafer, wherein the exposure process comprises an alignment step and an exposure step, and the scanner comprising:
an alignment apparatus; a wafer table, comprising at least one chuck hole to attach the wafer to the wafer table by vacuum chucking; and a controller, moving the wafer table to align the wafer with the alignment apparatus, detecting an actual position of each of a plurality of alignment marks on the wafer, calculating an index value based on a difference between a predicted position and the actual position of each said alignment mark, adjusting a vacuum pressure of the at least one chuck hole in the alignment step when the index value is larger than a first threshold value, controlling the scanner to finish the exposure process when the index value is smaller than or equal to the first threshold value.