Scanning charged particle microscope

Abstract

When a scanning image of a scanning charged particle microscope is impaired by an external disturbance, a disturbance frequency can be simply and precisely analyzed from the image in order to specify the external disturbance. The maximum frequency analyzable by the scanning charged particle microscope can also be increased up to several kHz, which is the rotation frequency of, for example, a turbo-molecular pump commonly used as an exhaust pump of the scanning charged particle microscope. In an FFT analysis of a stripe pattern which is an impairment of the scanning image, the scanning charged particle microscope performs a one-dimensional FFT (1D-FFT) in the Y-direction (sub-deflection direction of the charged particle beam) or a one-dimensional DFT (1D-DFT) in the X-direction (main deflection direction of the charged particle beam). To extend the analyzable maximum frequency up to several kHz, the scanning charged particle microscope also performs the 1D-FFT (or 1D-DFT) analysis in the X-direction (main deflection direction of the charged particle beam) along which the charged particle beam has a fast scanning speed.

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