Scanning-type instrument utilizing charged-particle beam and method of controlling same

Abstract

A scanning-type instrument is realized which utilizes a charged-particle beam and automates adjustments, if a voltage is applied to the specimen, to thereby provide excellent operational controllability. When a voltage is applied to the specimen, the electron beam would normally defocus. A signal corresponding to the voltage applied to the specimen is supplied to a CPU. An objective lens current is supplied to the coil on the objective lens from a power supply under control of the CPU to refocus the beam. As a result, the beam hitting the specimen is prevented from defocusing if a voltage is applied to the specimen. When the strength of the objective lens is varied, scanning signals to the deflection coils are adjusted in response to the variation. Variation in the magnification of the image and rotation of the image are corrected.

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