| 摘要 |
PURPOSE:To set off the aberration of an electron beam caused by an electrostatic field by forming the grid of a three-pole electron gun by the use of a nonmagnetic material, and forming the anode by the use of a magnet having a first annular magnetic substance and a second annular magnetic substance. CONSTITUTION:The three-pole electron gun of an electron beam exposure device is constituted of a cathode 1, a grid 2a made of a nonmagnetic material, and an anode 3a consisting of a first annular magnetic substance 6a the centre of which coincides with the axial line 5 of an electron beam and a second annular magnetic substance 8a placed outside the first magnetic substance 6a with a space 7a provided between the magnetic substances 6a and 8a; a coil 9a is wound around the space 7a. An aberration caused by the electrostatic field of the electron beam is set off by the magnetic field of the anode 3a. As a result, the intensity of the magnetic field does not become unstable even when the temperature of the grid 2a is increased. Besides, the magnetic line of force of the anode 3a reaches up to a space between the cathode 1 and the grid 2a, thereby the effect of setting off the aberration can be enhanced. |
