| 摘要 |
PURPOSE:To improve secondary electron collecting efficiency and S/N by providing a secondary electron collecting lens between a specimen and a secondary electron detector. CONSTITUTION:Secondary electrons (e) emitted from a specimen 5 are trapped by a strong magnetic field formed by the upper magnetic pole piece 2 of an objective lens and the lower magnetic pole piece 4, of the objective lens and allowed to rise toward the incident direction of an electron beam 1 while rotating substantially around an optical axis Z of the electron beam 1 and reach near an imagery point A. On the other hand, secondary electrons e1, e2, e3 out of the optical axis Z are corrected in their orbitals in the direction of the imagery point A due to lens effect of an electromagnetic lens 11. Here, hightension is applied to the electrode 8 of a secondary electron detector 6 disposed in the vicinity of the imagery point A, so that the secondary electrons (e) moving near the point A and the orbital-corrected secondary electrons e1, etc., are attracted by the electric field formed by the electrode 8, allowed to be incident on the secondary electron detector 6 and detected. |
