SUPERPOSE ACCURACY MEASURING METHOD AND SUPERPOSE DECISION METHOD EMPLOYING IT

摘要

PROBLEM TO BE SOLVED: To measure the superpose accuracy efficiently while shortening the measuring time by introducing an image processing technology. SOLUTION: In the superpose accuracy measuring method, a box mark is divided by a CCD into pixels 3 for an arbitrary shop on a wafer and the brightness of each pixel is converted into a current value of 256 gradations which is then stored as one image memory. After the images for all measuring shots are picked up, the current value of 256 gradations is integrated for an inner box 2 which is then laminated and the X, Y distribution of laminated inner box is represented numerically as a correlation coefficient.