Patent ID: 6825480
Filing Date: 2004-11-30
Classification: G01R,H01J

Abstract:
A charged particle beam apparatus comprising:a stage for setting a sample; a charged particle optical system for converting a charged particle beam emitted by a charged particle source; a scanning unit for irradiating said charged particle beam converged by said charged particle optical system to said sample in order to scan said sample; a focal position control system for controlling a focal position of said charged particle beam converged by said charged particle optical system; an astigmatism adjustment unit for adjusting astigmatism of said charged particle beam converged by said charged particle optical system; a particle image detection unit for obtaining a plurality of 2-dimensional particle images by detection of a particle images generated by said sample scanned by the irradiation of said charged particle beam converged by said charged particle optical system, where a single 2-dimensional particle image is obtained for each focal position; an image processing unit for computing a focal offset and said astigmatism of said converged charged particle beam on the basis of said plurality of 2-dimensional particle images obtained by said particle image detection unit at different focal positions controlled by said focal position control system; and a control system for adjusting and controlling said astigmatism of said converged charged particle beam by feeding back an astigmatism correction quantity based on said astigmatism computed by said image processing unit to said astigmatism adjustment, wherein a cross-sectional shape of said charged particle beam at an astigmatism adjusted focal position is circle and said image processing means computes said astigmatism by using at least three directional sharpness magnitudes which are obtained from said single 2-dimensional particle image at each focal position, wherein said charged particle beam apparatus creates a pattern, said pattern including edge components in at least 3 directions on said sample, said pattern having at least 3 areas, each of said areas for creating a sub pattern having one of said edge components in one of said directions on said sample.