Patent ID: 8017918

Claim:
A charged-particle beam instrument for observing or analyzing a specimen by receiving the specimen in a specimen chamber formed in an electron optical column and irradiating the specimen with an electron beam, said charged-particle beam instrument comprising: top and bottom polepieces disposed on the beam entrance side and the exit side, respectively, of the specimen chamber and provided with beam passage holes, the top and bottom polepieces forming the specimen chamber; an upper aperture stop made of metal foil or sheet having plural holes, the upper aperture stop being located on a side of an opening end of the beam passage hole in the top polepiece that faces into the specimen chamber, the top polepiece being located on the beam entrance side of the specimen chamber; a first pushing mechanism for pushing the upper aperture stop toward the top polepiece and supporting the upper aperture stop, the pushing mechanism stopping from pushing the upper aperture stop toward the top polepiece in response to a manipulation performed outside the electron optical column; an upper aperture stop drive mechanism for sliding the upper aperture stop in a direction perpendicular to a path of the electron beam in response to a manipulation performed outside the electron optical column; a lower aperture stop made of metal foil or sheet having plural holes, the lower aperture stop being located on a side of an opening end of the beam passage hole in the bottom polepiece that faces into the specimen chamber, the bottom polepiece being located on the beam exit side of the specimen chamber; a second pushing mechanism for pushing the lower aperture stop toward the bottom polepiece and supporting the lower aperture stop, the second pushing mechanism stopping from pushing the lower aperture stop toward the bottom polepiece in response to a manipulation performed outside the electron optical column; and a lower aperture stop drive mechanism for sliding the lower aperture stop in the direction perpendicular to the path of the electron beam in response to a manipulation performed outside the electron optical column.