Patent ID: 6770887
Filing Date: 2004-08-03
Classification: H01J

Abstract:
Aberration-correcting charged-particle optical apparatus comprising:a source of charged particles; a beam-defining aperture means; a plurality of condenser lenses; an aberration corrector comprising eight or more quadrupole lenses and three or more octupole lenses, one or more of which may be combined quadrupole/octupole lenses; a plurality of coupling lenses; a probe-forming lens comprising a coma-free plane; and a sample, in which said quadrupole lenses are so energized as to image three or more of said octupole lenses onto each other with different magnifications in different transverse directions, and said octupole lenses are energized so that axial aberrations of third order are eliminated and axial aberrations of fifth order are rendered small.