| 摘要 |
PURPOSE:To detect abnormality of exposure promptly, by comparing an output of a detector for detecting varying amount of an analogue signal with a given value, and by considering that there exist erroneous data and thus abnormal exposure if the output exceeds the given value. CONSTITUTION:After an electron beam 22 radiated from an electron gun 21 passes through an electron lens 23 and large deflector 24 for determining an exposure field, the beam 22 is shaped in a rectangle by a slit 25, is deflected by a deflector 26, is shaped in a required beam shape by a slit 27, and is irradiated through a lens 28 by a small-deflecting deflector 29 for positioning the beam 22 within the exposure field onto a given position on a sample. Exposure information from a CPU31 is input into a pattern generator 32 of which an output is fed to a digital-analogue converter 33 whose analogue signal is input into the deflector 26. Data concerning electron beam position to be exposed is fed to digital-analogue converters 34, 35 whose analoge signals are fed to deflectors 24, 29 respectively. Thus abnormality of exposure can be detected promptly by a simple constitution.
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