Patent ID: 7084399

Claim:
An ion beam apparatus comprising an ion beam optical system including ion generating means for generating ions, focusing means for focusing the ions generated from said ion generating means to form an ion beam, a restriction diaphragm having an opening for restricting current of said ion beam, beam deflecting means for scanning said ion beam on a sample and illuminating means for irradiating said ion beam on the sample, a sample stage for carrying the sample, secondary particle detecting means for detecting secondary particles generated from the sample under the irradiation of said ion beam, and control means for controlling said ion beam optical system, wherein said control means controls said ion beam optical system such that an ion beam for observation necessary to form a scanning ion microscope image of the sample or an ion beam for processing necessary to process the sample is formed and also controls said ion beam optical system such that when a beam current of the ion beam for processing is less than a predetermined value, a focusing/processing ion beam assuming a beam focusing state for high image resolution is formed and when the beam current of the processing ion beam is not less than the predetermined value, an ion beam for edge processing assuming a beam focusing state for permitting a sectional edge portion of the process sample to be processed sharply is formed, wherein said control means sets a desired processing region on a SIM image displayed on a CRT without regard to whether the focusing/processing ion beam or the edge processing ion beam is in use; and measures the beam radius of the edge processing ion beam in advance and stores a measured value in the control means wherein said control means, when processing with the edge processing ion beam, scans a region, obtained by automatically subtracting an amount corresponding to the stored beam radius from the set processing region, with the edge processing ion beam to thereby attain a desired high processing accuracy.