| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an electron beam lithographic apparatus capable of avoiding the fluctuations in measured values by dark current possessed by an optical position detector and performing high-precision height measurement, with respect to the height measurement of photomasks with a low reflectance. <P>SOLUTION: The electron beam lithographic apparatus is provided with a height-measuring means of photomask surfaces by optical measurement is provided with a readout means for the quantity of reflected light incident on an optical position detector; and a control means for automatically controlling the quantity of incident light irradiated from a light source, according to the kind of the photomasks for height-measurement in such a manner that the light quantity that is read out becomes a predetermined light quantity. The readout means reads out the quantity of reflected light, after the lapse of a predetermined standby time. The control means performs feedback control within the range of the light quantity values that can be read out by the readout means, when the light quantity that is read out does not reach the predetermined light quantity. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
