| 摘要 |
PURPOSE:To achieve the deflection having the low astigmatism in the wide range by splitting the hollow cylindrical electrode into the specific number to provide the X, Y direction deflector electrodes alternatively while arranging each electrode stripe chip in the positional relation symmetrical against the axis positioned at the particular angular position from x, y axis. CONSTITUTION:The hollow cylindrical electrode is splitted into 4+8m(m=1,2,3, 4.) in parallel with the central axis, where every other stripe will constitute the deflection electrode in X direction while the remaining stripe will constitute the deflection electrode in Y direction and said stripes constituting the X, Y direction deflection electrodes are arranged in such positional relation as symmetrical against the axis positioned at the angular position of 45 deg. from x, y axis. Consequently the charged particle beam can be deflected with high accuracy and high speed while the high order Fourier component can be removed resulting in the deflection having low astigmatism in the wide range. |
