Charged Particle Beam Device and Aberration Corrector

A charged particle beam application apparatus which irradiates a sample with a charged particle beam generated from a charged particle beam source, the apparatus comprising:

• a charged particle beam source;
• an aberration corrector that is disposed downstream the charged particle beam source;
• an objective lens that is disposed downstream the aberration corrector;
• and
• a control unit that controls the aberration corrector,
• wherein the aberration corrector includes
• a mirror that corrects aberration of the charged particle beam from the charged particle beam source,
• a beam separator that includes an entrance on which the charged particle beam from the charged particle beam source is incident and an exit from which the charged particle beam is emitted to the objective lens, and separates an incident trajectory on the mirror from the entrance and a reflection trajectory from the mirror to the exit from each other by deflecting the charged particle beam in an ON state, and
• a bypass optical system that is disposed at a position at which the trajectory of the charged particle beam bypasses when the beam separator is in the ON state and the trajectory of the charged particle beam passes through when the beam separator is in an OFF state within the beam separator, and
• wherein the bypass optical system controls the charged particle beam so that objective lens optical conditions at the trajectory via the mirror and the trajectory passing through the bypass optical system coincide with each other.