Patent ID: 7348558
Filing Date: 2008-03-25
Classification: G01R,H01J

Abstract:
1. A charged particle beam apparatus comprising: a stage for mounting a specimen, wherein the stage is movable at least in one direction; a calibration target fixed to the stage, wherein plural patterns having an edge component in at least three directions are formed on a surface of the calibration target; a charged particle optical unit for converging a charged particle beam emitted by a charged particle source; a scanning unit for irradiating and scanning the converged charged particle beam on the specimen and the calibration target; a focal point control unit for controlling a focal point of the converged charged particle beam; an astigmatism adjustment unit for adjusting astigmatism of the converged charged particle beam; an image detection unit for obtaining an image of the specimen by detecting particles generated from the specimen by the irradiating of the converged charged particle beam; an image processing unit for processing the image obtained by the image detection unit; and a control system for adjusting and controlling the astigmatism of the converged charged particle beam by computing an astigmatism correction quantity and a focal point correction quantity based on a focal offset and astigmatism of the converged charged particle beam obtained from a plurality of images of the calibration target by scanning the calibration target with the converged charged particle beam using the scanning unit, obtaining an image of the calibration target using the image detection unit and processing the obtained image of the calibration target using the image processing unit.