Patent ID: 7718976

Claim:
A charged particle beam apparatus comprising: a specimen stage on which a specimen is placed and held; an irradiation optics for scanning a primary charged particle beam on the specimen placed and held on the specimen stage; a detector for detecting secondary charged particles generated by the scanning of the primary charged particle beam, and display means for displaying an output of the detector as an image, wherein: the irradiation optics is equipped with a pair of accelerating electrodes and an aberration corrector that is placed between the pair of accelerating electrodes and corrects aberration of the primary charged article beam, the primary charged particle beam is accelerated during a period when being transmitted through the aberration corrector by a voltage being impressed across the pair of accelerating electrodes, and a plurality of multipole element groups for generating a quadrupole field and an octupole field of either or both of an electric field and a magnetic field and axisymmetric accelerating electrodes for a pre-stage and a post stage of the plurality of multipole element groups along the optical axis are built in the aberration corrector.