Method of positioning a beam to a specific portion of a semiconductor wafer

摘要

A method of positioning a beam to a specific portion of a semiconductor wafer is disclosed. In this method, the positions of two positioning marks formed on the wafer are measured. The position of another of the marks is calculated. Then, an actual position of the mark is measured. The calculated position and the actual position are compared with each other. It is judged whether or not the mark satisfies a predetermined condition. When the mark satisfies the predetermined condition, the specific portion of the semiconductor wafer is determined using the actual position of the mark. When it does not satisfy the predetermined condition, the specific area is determined using the position calculated using the positions of the marks around the mark.