| 摘要 |
PURPOSE:To improve accuracy of lithography by installing an aperture, whose diameter is larger than that of a crossover, at an enlarged-image position of the crossover. CONSTITUTION:An image is formed in the center of deflection in a blanking deflector 18, with lenses 12 and 13 serving as zoom lenses in an electrongun crossover 11. The crossover image is formed on a main surface of an object lens 16 by lenses 14 and 15. An aperture image of a beam-formation aperture mask 22 is formed on a sample plane 17 by lenses 15 and 16. A diameter of the aperture 23a is set sufficiently larger than that L of the crossover image. Hence, even if noises such as ripples on a centering coil of the object lens 16 cause the cross-over image to vibrate, the beams are not interrupted by the aperture 23a, not generating fluctuation in intensity of the beams on the sample plane 17.
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