The present invention relates to an electron beam lithography apparatus capable of accurately and efficiently correcting the drift of the electron-beam applying position.
The general electron beam lithography apparatus has a problem that a drawing position error occurs because an electron beam applied to a projection mask for light exposure or a circuit pattern on a silicon wafer drifts from a predetermined drawing position due to external fluctuation factors including the ambient temperature of an apparatus, atmospheric pressure, and external magnetic field such as earth magnetism, or internal fluctuation factors including electrification due to contamination in an electron beam column and fluctuation of deflection control system characteristics.
To solve the above problem, conventionally, a reference mark set on a sample stage is detected by the electron beam, the electron-beam deflecting signal value at the detection of the reference mark is compared with the preset standard signal value to obtain the difference between the values (deflection error or position error), and thereby, the drawing position error is corrected.
Japanese Patent Laid-open No. 63-308317(1988) discloses that, in order to further improve the above problem, an estimated curve of position drift is generated by using data for the deflection error (position drift) in drawing of several times in the past and thereby, the drift for the next-time drawing is estimated to previously correct the sample stage position, and moreover, the position drift is regularly measured in drawing to further correct the previously-corrected sample stage position each time.