| 摘要 |
PURPOSE:To control a beam current with high accuracy in proportional to the width of rectangular beam by storing the amplitude of signal obtained by differentiating the signal obtained from a substance through the scanning with charged beam and controlling a rate of deflection intensity of the two stages of deflection means in accordance with the maximum amplitude value among the stored values. CONSTITUTION:Prior to drawing of pattern, for example, when one of the width of crosssection of beam to be set is Xa, Yb, the deflection intensity of X direction deflector of two stages of deflectors 5a, 5b are changed so that the Y direction width is set to the reference width Y0 (width in the Y direction when deflection intensity of Y direction deflector of the two stages of deflectors 5a, 5b is set to zero) and the X direction width is set to Xa, the wire 12 is scanned with the beam having passed the aperture 9W for each change of deflection intensity and the signal detected by the Faraday cup 13 is sent to a differentiation circuit 15 through an amplifier. A computer 7 sequentially stores amplitude values of differentiated signals and also stores a ratio of deflection intensity when the maximum value is obtained as the adequate deflection intensity ratio of the X direction deflector of the two stages of deflectors 5a, 5b.
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