| 摘要 |
A lower pole piece of an electromagnetic superposition type objective lens is divided into an upper magnetic path and a lower magnetic path. A voltage nearly equal to a retarding voltage is applied to the lower magnetic path. An objective lens capable of acquiring an image with a higher resolution and a higher contrast than a conventional image is provided. An electromagnetic superposition type objective lens includes a magnetic path that encloses a coil, a cylindrical or conical booster magnetic path that surrounds an electron beam, a control magnetic path that is interposed between the coil and sample, an accelerating electric field control unit that accelerates the electron beam using a booster power supply, a decelerating electric field control unit that decelerates the electron beam using a stage power supply, and a suppression unit that suppresses electric discharge of the sample using a control magnetic path power supply. Thus, whether landing energy of an electron beam varies widely, the electron beam can be focused with the electromagnetic superposition type objective lens approached to the sample.
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