Charged-particle-beam exposure device and charged-particle-beam exposure method

A device for exposing a wafer to an electron beam, said device comprising:

• an electron gun emitting said electron beam;
• and
• an electron-beam optical system directing said electron beam to said wafer,
• said electron gun comprising:
• a cathode having a tip, said tip having substantially a circular conic shape and a tip surface substantially at a beam axis, said cathode being applied with a first voltage;
• an anode having a first aperture substantially on said beam axis and being applied with a second voltage higher than said first voltage;
• a control electrode having a second aperture substantially on said beam axis and having applied thereto a voltage lower than said first voltage to control a current of said cathode, said second aperture being larger than said tip surface;
• a guide electrode having a third aperture substantially on said beam axis, being arranged between said cathode and said anode and having applied thereto a voltage higher than said first voltage and lower than said second voltage, said third aperture being smaller than said tip surface;
• and
• a lens electrode having a fourth aperture substantially on said beam axis, arranged between said guide electrode and said anode and having applied thereto a voltage lower than said first voltage to form a cross-over image of said electron beam, said fourth aperture being larger than said third aperture.

A method of generating an electron beam traveling along a beam axis, said method comprising the steps of:

• heating a cathode having a tip surface;
• applying a first voltage to said cathode;
• applying a second voltage higher than said first voltage to an anode having a first aperture so as to accelerate electrons emitted from said cathode toward said anode;
• applying a voltage lower than said first voltage to a control electrode having a second aperture so as to control an amount of said electrons emitted from said cathode and passing through said second aperture;
• applying a voltage higher than said first voltage and lower than said second voltage to a guide electrode having a third aperture so as to guide some of said electrons from said tip surface through said second and third apertures in trajectories parallel to said beam axis;
• and
• applying a voltage lower than said first voltage to a lens electrode having a fourth aperture so as to form a cross-over image of said electron beam after said electrons pass through said second, third and fourth apertures.