Electron gun, charged particle gun, and charged particle beam apparatus using electron gun and charged particle gun

Patent metadata

Field	Value
Publication number	US-9570268-B2
Application number	US-201414787263-A
Country	US
Kind code	B2
Filing date	Apr 14, 2014
Priority date	Apr 25, 2013
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

Abstract

The purpose of the present invention is to provide a charged particle gun using merely an electrostatic lens, said charged particle gun being relatively small and having less aberration, and to provide a field emission-type charged particle gun having high luminance even with a high current. This charged particle gun has: a charged particle source; an acceleration electrode that accelerates charged particles emitted from the charged particle source; a control electrode, which is disposed further toward the charged particle source side than the acceleration electrode, and which has a larger aperture diameter than the aperture diameter of the acceleration electrode; and a control unit that controls, on the basis of a potential applied to the acceleration electrode, a potential to be applied to the control electrode.

First claim

The invention claimed is:

1. An electron gun comprising:
a needle-like electron source acting as a field emission type electron source; an acceleration electrode to accelerate an electron emitted from the electron source;
a control electrode disposed nearer to a side of the electron source than to a side of the acceleration electrode and having an aperture diameter larger than an aperture diameter of the acceleration electrode; and
a control section to control a potential applied to the control electrode based on a potential applied to the acceleration electrode.

2. The electron gun according to claim 1 , wherein provided that the aperture diameter of the acceleration electrode is defined as D and a distance between the electron source and the acceleration electrode is defined as L, a fraction of D to L is expressed with D/L<1.

3. The electron gun according to claim 2 , wherein the distance between the electron source and the acceleration electrode is defined as 6 mm<L<20 mm.

4. The electron gun according to claim 1 , wherein the electron gun is of Cold (Cathode) Field Emission (CFE) type.

5. The electron gun according to claim 3 , wherein the electron gun is provided with two or more pieces of control electrodes.

6. The electron gun according to claim 3 , wherein a drawing electrode is provided between the acceleration electrode and the control electrode.

7. The electron gun according to claim 5 , wherein the electron gun is provided with a control mechanism to switch over electrodes in use according to an acceleration voltage of the electron.

8. A charged particle beam apparatus employing the electron gun according to claim 1 , the apparatus comprising at least one or more pieces of one of electrostatic and magnetic field lenses; a sample stage on which an observation sample is placed; and a detector to detect at least one of a reflected electron and a secondary electron, wherein the sample is observed or analyzed by the electron beam.

9. The charged particle beam apparatus according to claim 8 provided with an electron optical system employing one piece of one of electrostatic and magnetic field lenses.

10. The charged particle beam apparatus according to claim 8 , wherein an outer diameter size of one of the electron gun and an objective lens is 200 mm or smaller.

11. The charged particle beam apparatus according to claim 8 provided with a function to observe the sample employing the electron beam with a lower acceleration, in which the acceleration voltage of the electron ranges from 0.1 to 3 kV.

12. A charged particle gun comprising:
a charged particle source; an acceleration electrode to accelerate a charged particle emitted from the charged particle source;
a control electrode disposed nearer to a side of the charged particle source than to a side of the acceleration electrode and having a larger aperture diameter than an aperture diameter of the acceleration electrode; and
a control section to control a potential applied to the control electrode based on a potential applied to the acceleration electrode.

13. A charged particle beam apparatus employing the charged particle gun according to claim 12 , the apparatus comprising:
a sample stage on which an observation sample is placed;
an objective lens to focus and irradiate the charged particle beam onto the sample; and
a detector to detect a secondary electron,
wherein the sample is observed or analyzed by the charged particle beam.

14. The charged particle beam apparatus according to claim 13 , wherein the charged particle drawn from the charged particle source are decelerated for use.

15. A charged particle gun comprising:
a charged particle source;
an acceleration electrode to accelerate a charged particle emitted from the charged particle source;
a control electrode disposed nearer to a side of the charged particle source than to a side of the acceleration electrode; and
a control section to control a potential applied to the control electrode based on a potential applied to the acceleration electrode, wherein the control section applies a control voltage to enhance an electric field at a tip end of the charged particle source to the control electrode when an acceleration voltage of the acceleration electrode is low whereas applying a control voltage to suppress the electric field at the tip end of the charged particle source to the control electrode when the acceleration voltage is high.

Assignees

• Hitachi High Tech Corp

Inventors

• Imai Yuta
• Ohshima Takashi
• Morishita Hideo

Classifications

• H01J27/02

  Ion sources; Ion guns {(for examination or processing discharge tubes H01J37/08; ion sources, ion guns for particle spectrometer or separator tubes H01J49/10; ion propulsion F03H1/00)} · CPC title

• H01J37/20

  Means for supporting or positioning the object or the material; Means for adjusting diaphragms or lenses associated with the support · CPC title

• H01J27/26

  using surface ionisation, e.g. field effect ion sources, thermionic ion sources (H01J27/20, H01J27/24 take precedence) · CPC title

• H01J37/28

  with scanning beams {(H01J37/268, H01J37/292, H01J37/2955 take precedence)} · CPC title

• H01J37/06

  Electron sources; Electron guns · CPC title