Patent ID: 9018597
Filing Date: 2015-04-28
Classification: H01J

Abstract:
1. An ion beam apparatus comprising: a gas field ionization ion source for generating an ion beam; a sample stage for holding a sample; a lens system that focuses the ion beam emitted from the gas field ionization ion source so as to be irradiated onto the sample; a deflection system that deflects the ions so as to change the irradiation position of the ion beam on the sample; a secondary particle detector for detecting secondary particles emitted from the sample; an image processing unit for forming an observation image of the sample by using the detection results of the secondary particle detector; and a control unit for controlling the lens system and the deflection system so as to adjust the irradiation position of the ion beam, wherein the gas field ionization ion source comprises: an emitter electrode having a needle-shaped apex provided with a micro-protrusion having a single atom or a trimer at the apex thereof; an extraction electrode having an opening at a position spaced apart in an apex direction from the emitter electrode; a gas supply unit for supplying a gas to the vicinity of theapex of the emitter electrode; a gas pressure control unit for controlling the pressure of the gas; an extraction voltage applying unit for forming an electric field to ionize the gas in the vicinity of the apex of the emitter electrode by applying an extraction voltage between the emitter electrode and the extraction electrode; and an ion source control unit that controls so as to emit an ion beam at least in two operation states including a first operation state in which, when a first extraction voltage is applied, with the gas pressure being set to a first gas pressure, ions are emitted from a first ion emission region at the apex of the emitter electrode, and a second operation state in which, when a second extraction voltage that is higher than the first extraction voltage is applied, with the gas pressure being set to a second gas pressure that is higher than the first gas pressure, ions are emitted from a second ion emission region that is larger than the first ion emission region, with the ion beam being controlled so that the ion beam current on the sample in the second operation state is greater than the ion beam current on the sample in the first operation state.