| 摘要 |
PROBLEM TO BE SOLVED: To accurately work out the amount of deviation between a reference mark and an alignment mark, and to enhance the reliability of the amount of deviation, by a method wherein the error between the reference mark and the alignment mark is computed, and the error is reflected to the positional deviation between the reference mark and the alignment mark. SOLUTION: The value of reference mark is worked out from an image profile by a reference value computer 21 in a control means 11, the above- mentioned value is stored and controlled in a reference value control means 22. The error of alignment mark is worked out from the value of controlled reference mark by an error computing means 23. On the other hand, the positional deviation information of the alignment mark measured from the image profile is computed by a positional deviation computing means 24, and the amount of corrected deviation is computed based on the positional deviation information and the error information by a deviation amount computing means 25. As above- mentioned, the preciseness of alignment can be measured accurately by computing the correct amount of deviation between the reference mark and the alignment mark. |
