Electron lens and the electron beam device
AssigneeParam Corporation
InventorHiroshi Yasuda
Life of this patent
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Abstract
There provided a device for effectively drawing a fine pattern using a permanent magnet. The device has an outer cylinder 201 composed of a cylindrical ferromagnet with a Z axis as a central axis, a cylindrical permanent magnet 202 located inside the outer cylinder and polarized along the Z axis direction, a correction coil 204 located inside the cylindrical permanent magnet with a gap from the cylindrical permanent magnet, for adjusting a magnetic field strength generated by the cylindrical permanent magnet along the Z axis direction, and a coolant passage 203 located in the gap between the cylindrical permanent magnet and the correction coil, for allowing a coolant to flow therethrough and controlling temperature changes in the cylindrical permanent magnet.
Claims5
An electron lens used in an electron beam device having an electron gun for emitting an electron beam in a Z axis direction, the electron lens comprising:
- an outer tube composed of a tubular ferromagnet with the Z axis as a central axis;
- a tubular permanent magnet located inside the outer tube and polarized along the Z axis direction, the electron beam going through;
- a ferromagnetic ring which is thinner in the z axis direction and homogenizes a magnetic field generated by the tubular permanent magnet is located on an end surface of an electron beam emission side of the tubular permanent magnet along the Z axis direction wherein the inner diameter of the ferromagnetic ring is almost the same as that of the tubular permanent magnet, its outer diameter is smaller than the outer diameter of the cylindrical permanent magnet.
Dependencies are inferred from the claim text.