| 摘要 |
PURPOSE:To reduce the influence of an electron beam incidence hole and to take a precise analysis by decelerating and diverging an electron beam which is led out by a high-potential lead-out grid by a plane decelerating grid. CONSTITUTION:An electron beam 1 is supplied from the electron beam incidence hole 2 to illuminate an LSI wiring sample 3, which emits the secondary electron. The secondary electron is led out by the plane lead-out grid 6 which is provided nearby the sample 3 and applied with a high voltage from a DC power source 5 and travels to an analytic grid 4 while accelerated to a high speed. The grid 6, however, is applied with the too high voltage, so the secondary electron is concentrated on the center and all secondary electrons leak from the incidence hole 2 without passing among grids 4. For the purpose, the decelerating grid 7 consisting of the plane decelerating grid 70 and a hemispherical decelerating grid 71 is provided on the grid 6. Consequently, secondary electrons which are led out by the grid 6 with a uniform decelerating electric field produced between the grids 6 and 70 and never leaks from the incidence hole 2 of the grid 4.
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