Patent ID: 8035086

Claim:
An aberration correction apparatus for correcting an aberration of an objective lens in a charged particle beam apparatus, comprising: a first multipole lens that is arranged on the objective lens side; a second multipole lens that is arranged on a projection lens side; a first transfer lens group for transferring a coma-free condition of the objective lens to the second multipole lens, that is arranged between the first multipole lens and the second multipole lens; and a second transfer lens group for transferring a coma-free condition of the objective lens to the first multipole lens, that is arranged between the first multipole lens and the objective lens; wherein the second transfer lens group includes three rotationally symmetric lenses, and when the three rotationally symmetric lenses are defined as a first, a second, and a third rotationally symmetric lens in order of proximity to the objective lens, it is possible to correct an aberration of the objective lens in a case in which a focus of the objective lens is inside or outside the objective lens by using the second transfer lens group while switching between a combination of the third rotationally symmetric lens and the first rotationally symmetric lens and a combination of the third rotationally symmetric lens and the second rotationally symmetric lens.