Patent ID: 7619218
Filing Date: 2009-11-17
Classification: H01J

Abstract:
1. A scanning charged particle optical microscope comprising: an irradiation optical system for scanning a specimen with a charged particle beam; a specimen stage for supporting the specimen; a detecting optical system for detecting secondary charged particles generated from the specimen by irradiation with the charged particle beam; a control unit to control the irradiation optical system; and a power supply including a current source and a voltage source; wherein the irradiation optical system includes a charged particle gun, an objective lens, and an aberration corrector arranged between the charged particle gun and the objective lens, wherein the aberration corrector includes a first pair of multipole lenses, each pole having a first coil, and a second pair of multipole lenses between the first pair of multipole lenses, each pole having a second coil and a voltage input terminal, wherein the first coils and the second coils are connected to the current source, and the voltage input terminal is connected to the voltage source, and wherein the control unit is arranged to control whether a voltage of the voltage source is applied to the voltage input terminal, in accordance with an accelerating voltage of the charged particle beam.