| 摘要 |
PURPOSE:To make it possible to carry out an oblique radiation at a desired oblique angle accurately, by finding the incident angle of the ion beam to a sample. CONSTITUTION:A pedestal mark 17 is scanned by an image drawing deflector 14a or 14b in a condition not inclining the beam, that is, not applying voltage to an oblique radiation deflector 15. When the mask 17 receives ion beams, secondary electrons are radiated by the edge 17b. As a result, every time the ion beam passes the edge 17b, a microchannel plate MCP 16 outputs a secondary electron detecting signal. The signal is amplified 18 and delivered to a display unit 19. The unit 19 displays the said signal as a still picture image by a signal synchronous to the scans of the ion beam. An arithmetic unit 20 receives the deflected voltage output from the display unit 19 and finds the deflecting angle thetathrough an operation. Then the pedestal mark 17 is detected in the condition of inclining the ion beam in the same manner. The incident angle theta can be found by the deflecting voltage at the time.
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