| 摘要 |
PROBLEM TO BE SOLVED: To realize a scanning electron microscope formed so that the position of a deflection supporting point of the electron beam always passes through the main surface position of an objective lens, even if the position of the lens main surface of the objective lens is changed. SOLUTION: A CPU 15 controls an objective lens drive circuit 13 through a D/A conversion unit 14, and when the strength of the excitation of an objective lens 5 is changed, the CPU 15 reads out the data of the deflection angle of deflecting coils 7, 8 corresponding to the strength of the excitation of the objective lens 5 from a memory 16. This data is supplied to a drive circuit 10 via a D/A converting unit 9 so as to drive the deflecting coil 7, and angle of deflection of the electron beam by the deflecting coil 7 is changed, and the data is supplied to a drive circuit 12 through a DA converting unit 11 so as to drive the deflecting coil 8, and the angle of deflection of the electron beam by the deflecting coil 8 is thereby changed. As a result, even if the strength of the excitation of the objective lens is changed, the electron beam scans around the center position of the main surface of the objective lens as a deflection support point without generating the deflection of a scanned image, and the generation of astigmatism is prevented, and a scanned image having high resolution is obtained.
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