| 摘要 |
PURPOSE:To sufficiently reduce an apparent deflection distortion by providing three or more auxiliary lenses for reregulating the focus of charged particle beam at every deflecting point. CONSTITUTION:Charged particle beam emitted from an article point is focused through a main lens 5 on the center 2 of a sample surface 3. Charged particles deflected by a deflector 4 become an orbit 11, and further pass the out of the axis of a main lens to be deflected to become an orbit 12. Auxiliary lenses 61, 62, 63 are provided, focused, and corrected for the distortions of x- and y-directions. The orbits become 15, 16, 17 and can be freely controlled including the rotation around the optical axis. |
