ION MILLING DEVICE

PROBLEM TO BE SOLVED: To provide an ion milling device that performs drilling on an optimum different irradiation condition for each different sample for an electron microscope, shortens irradiation time of an ion beam, and reduces burden of an operator. SOLUTION: A passage ion measuring means comprising an electrode plate 15 and a galvanometer 14 measures ion current of passage ions at a predetermined time interval, estimates variation of drilling depth (h) of a sample 5 based on variation information on this ion current, and adjusts valve openings and acceleration voltages of a control valve 11 and a variable voltage source 13 so that the variation of drilling depth (h) matches with an expected drilling depth variation. Therefore, the drilling can be completed within a time approximate to the whole irradiation time input by the operator. The opening information of the control valve 11 and the voltage information of the variable voltage source 13 for each different sample for the electron microscope are made optimum, and similar repeated drilling of the samples 5 is efficiently performed. COPYRIGHT: (C)2007,JPO&INPIT