Patent ID: 6459082
Filing Date: 2002-10-01
Classification: H01J

Abstract:
In a focused ion beam system having an emitter acting as an ion beam source, an extraction electrode for extracting an ion beam from the emitter, an acceleration electrode for imparting energy to the extracted ion beam, at least one lens for focusing the ion beam, means for flashing the emitter by heating the emitter to increase the temperature for a period of time to remove contaminates from the emitter, and a specimen stage on which a specimen to be irradiated with the focused ion beam is placed,the improvement comprising means for accumulating emission time from the last flashing, and control means for determining a voltage applied to the extraction electrode and regulating emission current from the emitter, said control means determining the voltage to be applied to the extraction electrode at intermittent times and continuously applying a voltage to the extraction electrode, the voltage applied to the extraction electrode being set as a function of a target emission current to be achieved, a currently measured emission current, and an accumulated emission time from the last flashing.