| 摘要 |
PURPOSE:To enable observation of three-dimensional secondary-electron images with secured high resolution by placing a sample in the magnetic field of a lens, which produces a lens magnetic-field forming a simple lens, and placing secondary-electron detectors below the sample. CONSTITUTION:An objective lens is constituted of a york 7, an inner and an outer magnetic poles 8 and 9, and an excitation coil 10. The lower end surface of the outer magnetic pole 9 is located in the same or a heightened surface level of the lower end surface of the inner magnetic pole 8, so that a lens magnetic-field is formed below the end surfaces of the magnetic poles 8 and 9. The excitation current is adjusted so that the lens magnetic-field becomes a simple lens. A sample 11 is placed in the magnetic field located under the inner magnetic pole 8, and secondary electrons discharged from the sample 11 are detected with detectors 12a-12c. The detector 12a, as usual, is placed over the lens. The detectors 12b and 12c are placed in the same or a lowered surface level of the sample 11 so that they are symmetrical to the axis of light. |
