| 摘要 |
PROBLEM TO BE SOLVED: To reduce the number of times of the movement of a stage at the time of an alignment of an electron beam with a wafer by a method wherein the widths of an alignment mark are found from a reflected electron signal generated from the alignment mark, the scanning direction of the electron beams, in which the widths of the mark become narrowest, is calculated and the value of the calculated scanning direction is decided as the deviation amount of the direction of rotation of the coordinate system of the stage from the direction of rotation of the coordinate system of the wafer. SOLUTION: An electron beam 42 is scanned in the direction parallel to the X-axis of the coordinate system of a state in such a way as to cross completely an alignment mark 41. At this time, the strength of reflected electrons is detected by a reflected electron detector in synchronization with the scanning and the widths W (θ0) of the mark 41 are found from the obtained reflected electron signal 43 using properly a signal processing algorithm. Moreover, the scanning direction of the beam 42 is charged in order in the direction of rotation of the stage at the angles ofθ1 toθ3 degrees, that is, in X' to X''' directions, the respective widths W (θ1 toθ3) of the mark 41 are found to calculated the scanning direction of the beam 42, in which those widths W (θ1 toθ3) of the mark 41 become narrowest, and the value of the calculated scanning direction is decided as the deviation amount of rotation of the coordinate system of the stage from the coordinate system of a wafer.
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