Electronic bi - mu home position lighting control method and electronic bi - mu home position lighting control control equipment

摘要

PURPOSE:To correct the drift of the electron beam by storing the pattern of a predetermined region of the sample prior to measurement and feeding the result of comparison between the detection result obtained in the midst of measurement and the stored result. CONSTITUTION:Prior to measurement, the pattern of a predetermined region of a sample 4 is detected and the resulting image signal is converted into a binary one by a voltage comparator 10. And, the binary signal is introduced into a CPU 13 through a shift resistor 11 and a serial/parallel converter 12 and then is stored in a magnetic disk device 14. During measurement, the pattern is detected while controlling positioning by the CPU 13 and the binary data of the image signal is compared with the stored data in the CPU 13. Then, a deflecting coil 3 is controlled by feeding back the comparison result through a D/A converter 16. Accordingly, it is possible to accurately irradiate the electron beam upon a predetermined region by automatically correcting the drift of the electron beam in the midst of measurement.