| 摘要 |
PURPOSE:To correct the deflection of a primary electron beam due to an electric field for secondary detection as well as to make the secondary electron too emitted out of a sample detectable in an efficient manner, by installing a device which deflects the primary electron beam at the opposite side to a secondary electron detector. CONSTITUTION:A secondary electron detector 3 is being impressed with a voltage of about +10kV in order to convert a deflected secondary electron 7 into light by means of acceleration. Simultaneously, the electric field produced by this voltage is formed on top of an objective lens 2 and induces the secondary electron emitted out of a sample 1. At the same time, the orbit of a primary electron beam 6 is eventually bent in consequence. Accodingly, each of corrective exciting coils 8-1 and 8-2 having both S-N poles is installed in a position crossed at right angles with the secondary electron detector 3, thereby forming an electric field. With excitation given under configuration like this, the primary electron beam 6 corrects as much as a portion for being deflected by the secondary detector 3 and can make it incident into the center axis of the objective lens 2. Simultaneously, also the secondary electron 7 emitted out of the sample 1 is bent of its orbit to the side of the secondary electron detector 3 whereby such an effect as improving the additional efficiency of the secondary electron can be brought into full play simultaneously. |
