| 摘要 |
This aberration corrector comprises a mirror (108) for correcting a charged particle beam aberration, a beam separator (107), and a bypass optical system (109) inside the beam separator. The beam separator (107) comprises a charged particle beam entrance (117A), and an exit (117C) wherefrom the charged particle beam is ejected toward an objective lens (110). In an ON state, the beam separator (107) separates an injection trajectory, from the entrance (117A) to the mirror (108), and a reflection trajectory, from the mirror (108) to the exit (117C), by deflecting the charged particle beam. The bypass optical system (109) is disposed at a position which is where the charged particle beam trajectory passes through when the beam separator (107) is in an OFF state, and is bypassed by the charged particle beam trajectory when the beam separator (107) is in the ON state. The bypass optical system (109) controls the charged particle beam in such a manner that the objective lens optical conditions are matching between the trajectory via the mirror (108) and the trajectory passing through the bypass optical system (109). |
