Patent ID: 9256138
Filing Date: 2016-02-09
CPC Classification: G03F

Claim Text:
1. A method for measuring distortion of a projection objective, comprising: disposing a reticle on a reticle stage and disposing a substrate on a workpiece stage, the reticle having a plurality of marks formed thereon; performing a stepping and exposing process of the reticle stage, including: performing a stepping and exposing process of the workpiece stage, including: subtracting a motional error of the reticle stage and/or the workpiece stage from each first positional deviation to obtain a plurality of first corrected deviations, and subtracting a motional error of the reticle stage and/or the workpiece stage from each second positional deviation to obtain a plurality of second corrected deviations; and calculating a plurality of differences each between one of the plurality of second corrected deviations and a corresponding one of the plurality of first corrected deviations, and calculating a distortion of the projection objective based on the plurality of differences.