ION SOURCE DEVICE AND ITS OPTIMUM CLEANING METHOD

PROBLEM TO BE SOLVED : To provide an ion source device for removing insulating film adhered to a lead out electrode system and its optimum cleaning method. SOLUTION : The ion source device 1 comprises a rare gas supply source 60 which supplies a rare gas instead of an ion source gas 10 into a plasma chamber and a means of determining time duration and timing for cleaning the electrodes based on the deposited amount of the insulating film adhered to the electrodes 20, 30, 40, 50 of the lead out electrode system, and by adjusting the lead out voltage and supply amount of the rare gas as a setting parameter, the insulating film is removed by sputtering of ion beam of the rare gas. In this method, the setting parameter for changing the beam diameter of ion beam of the rare gas at the time of colliding with each electrode face of the lead out electrode system 3 is adjusted, and by converging the ion beam of the rare gas within an effective setting range of beam diameter that has a high strength of sputtering the insulating film, the insulating film is uniformly removed.