| 摘要 |
PURPOSE:To enable the comparison between the transmission scan image and the secondary electron image on the front and rear faces of the specimen, by providing a detector for the secondary electron produced from the upper and lower faces of the specimen and means for displaying the image based on said detected signal. CONSTITUTION:Secondary electron detectors 7, 8 for detecting the secondary electron from the upper and lower faces of the specimen due to the electron beam 2 scanning on the specimen 4 are arranged above and below the specimen 4. Then the detection signal produced from the detectors 7, 8 is amplified by the amplifiers 9, 10 and the image is selectively displayed on a cathode ray tube 12 through an exchange switch 11 while simultaneously a passed scan image is displayed on a cathode ray tube 15 by the electron beam passed through the specimen 4. The information connerning to the front and rear of the specimen 4 may be displayed simultaneously as two independent images on the screen of the cathode ray tube 12. Consequently the transmission scan image and the secondary electron image can be compared to discriminate the adhesion of dust on the front and the rear of the specimen. |
