METHOD FOR MEASURING DISTORTION OF PROJECTION OBJECTIVE

摘要

A method for measuring a distortion of a projection objective comprises: through reticle stage step exposure (S21), obtaining a first positional deviation between two exposed patterns in the same exposure field; through workpiece stage step exposure (S22), obtaining a second positional deviation between two exposed images in the same exposure field; and eliminating motion errors of a reticle stage and/or workpiece stage in the first and the second positional deviation, to obtain a first and a second corrected deviation (S43, S44), subtracting one corrected deviation from the other corrected deviation (S45), and obtaining a distortion of a projection objective through fitting (S46).