PROJECTION EXPOSURE METHOD

PROBLEM TO BE SOLVED: To correct expansion and contraction distortion in both directions of X and Y, etc., and to enhance the superimposing accuracy of patterns on a mask, etc., on those on a substrate by detecting the positions of the target patterns at least at three points which are arranged on a nonlinear line, so as to detect the expansion and contraction distortion in both directions of X and Y, etc., of a wafer. SOLUTION: Three points of patterns 11-13 are provided on the substrate 10 and the target patterns 14-16 on the mask or a reticle are superimposed on these target patterns 11-13. These patterns 11-13 are arranged out of the same line and the distance A between the target patterns 11 and 12 is detected to detect the expansion and contraction distortion in the direction of X. Further, the distance B between a straight line which links the target patterns 11 and 12 and the target pattern 13 is obtained to detect the expansion and contraction distortion in the direction of Y. Further, an orthogonal degree in the directions of X and Y can be detected by the difference between the detected X-coordinate of the pattern 13 and the X-coordinate of the pattern 13 for setting calculated from the measurements of the patterns 11 and 12.