A MARK SIGNAL AMPLIFIERAbstract of the DisclosureThis invention relates to a mark signal amplifierfor use in apparatus for electron-beam lithography. Itincludes a first circuit for taking maximum and minimumvalues out of a mark signal that is detected by causingan electron beam to scan a mark area provided on a sample.A second circuit determines a peak-peak value of anamplitude of the detected mark signal in accordance withthe maximum and minimum values, and a third circuit sendsan output signal of a constant amplitude level to a binary-coding circuit in accordance with the peak-peak value in spiteof fluctuations of the detected mark signal. The arrangementenables a higher accuracy than hitherto to be obtained indetecting the mark positioning.
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