| 摘要 |
PROBLEM TO BE SOLVED: To provide an aberration corrector which simultaneously corrects spherical aberration and chromatic aberration against charged particle beams. SOLUTION: Two stages of multipole elements 12, 13 are installed, each of which has a thickness along the optical axis 11, and generates three-fold symmetric electrostatic field or static magnetic field, and two-fold or three-fold symmetric static electromagnetic field is superimposed on it. In respective multipole elements in two stages, the chromatic aberration is corrected by setting the static electromagnetic field so as to nearly cancel magnetic deflecting force and electrical deflecting force with respect to an electron beam 17 of a prescribed acceleration voltage, while the spherical aberration is corrected in the three-fold symmetric electrostatic field or static magnetic field where the multipole elements 12, 13 are formed. COPYRIGHT: (C)2010,JPO&INPIT |
