| 摘要 |
PROBLEM TO BE SOLVED: To provide an electronic optical apparatus without aberration by using an electronic lens having a central hole for passing an electron beam and having a rotation symmetric structure. SOLUTION: Three electron beams 20, 21, 22 different in energy emitted from an electron source 9 move along a quite identical track until they enter into an aberration correcting lens part, but when they enter into the correcting lens part, the electron beams 20-22 cross an optical axis by an action of the correcting lens part energized by a power supply for energizing a correcting lens 27, after that, the electron beams 20-22 are dispersed to three electron beams 20-22 according to the difference in energy. The dispersed electron beams 20-22 are collected again and irradiates an identical point on a sample 11 by an focusing action of an objective lens part energized by a power supply for energizing an objective lens 28. That is, a color aberration correction of the apparatus is executed by matching a refractive effect at the correcting lens part to a refractive effect at the objective lens part even if the dispersed electron beams 20-22 are different in energy. A spherical aberration correction is also executed in the similar process. COPYRIGHT: (C)2005,JPO&NCIPI
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