| 摘要 |
PURPOSE:To remarkably shorten the exposure time in a mark detecting method by calculating a mark signal detecting step and a mark signal detecting data and approximately performing it in parallel with the step of measuring the position of a mark. CONSTITUTION:A mark M is canned by a charging beam with a beam having a scanning width L designated in advance, a distance a from the left scan starting point to the mark and a distance b from a right scan starting point to the mark are detected, an operation of measuring the value of{a+[L-(a+b)]/2}from these numerical values is performed several times, and their average value is calculated. In this case, the average value of the values measured by scanning the marks up to m times m(m<n) while scanning the mark at n times is calculated, and the position of the center of the mark is detected. Since it does not almost apparently take a time to measure the position of the mark in this manner, the exposure time can be resultantly remarkably shortened. |
