Electron source, electron gun, and charged particle beam device

Patent metadata

Field	Value
Publication number	US-12394585-B2
Application number	US-202017928401-A
Country	US
Kind code	B2
Filing date	Jun 29, 2020
Priority date	Jun 29, 2020
Publication date	Aug 19, 2025
Grant date	Aug 19, 2025

Abstract

In an electron source including a suppressor electrode having an opening at one end portion thereof in a direction along a central axis and an electron emission material having a distal end protruding from the opening, the suppressor electrode further includes a receding portion receding to a position farther from the distal end of the electron emission material than the opening in the direction along the central axis at a position in an outer peripheral direction than the opening, and at least a part of the receding portion is disposed within a diameter of 2810 μm from a center of the opening. Accordingly, an electron source, an electron gun, and a charged particle beam device such as an electron microscope using the same, in which a machine difference in a device performance due to an axial shift between the electron emission material and the suppressor electrode is reduced, are implemented.

First claim

The invention claimed is:

1. An electron source comprising:
a suppressor electrode having an opening at one end portion thereof in a direction along a central axis; and
an electron emission material having a distal end protruding from the opening, wherein
the suppressor electrode further includes a receding portion receding to a position farther from the distal end of the electron emission material than the end portion of the suppressor electrode in the direction along the central axis at a position in an outer peripheral direction than the opening, and
at least a part of the receding portion is disposed within a diameter of 2810 μm from a center of the opening.

2. The electron source according to claim 1 , wherein
the end portion of the suppressor electrode is a plane perpendicular to the central axis.

3. The electron source according to claim 2 , wherein
the plane has a diameter of 720 μm or more.

4. The electron source according to claim 1 , wherein
the receding portion includes a tapered portion having at least two or more different angles formed with a surface perpendicular to the central axis.

5. The electron source according to claim 1 , wherein
the receding portion includes a portion parallel to the central axis.

6. The electron source according to claim 1 , wherein
the receding portion includes a curved surface portion of which an angle formed with a surface perpendicular to the central axis continuously changes.

7. The electron source according to claim 1 , wherein
the receding portion includes a tapered portion forming an angle θ with a surface perpendicular to the central axis,
at least a part of the tapered portion is disposed within a diameter L from the center of the opening, and
the diameter L and the angle θ satisfy a relationship of 2.40×10 7×L2+3.18 ×10 4×L−4.08×10 1≤log θ≤6.68×10 7×L2−2.68×10 4×L+1.08, the diameter being expressed in units of μm, and the angle θ being expressed in units of degrees (°).

8. The electron source according to claim 1 , wherein
at least a part of the receding portion is disposed within a diameter L from the center of the opening,
the electron emission material protrudes from the opening by a length T, and
the diameter L and the length T satisfy a relationship of L=3.53T+1607, both the diameter L and the length T being expressed in units of μm.

9. The electron source according to claim 1 , wherein
the receding portion includes a tapered portion forming an angle θ with a surface perpendicular to the central axis,
at least a part of the tapered portion is disposed within a diameter L from the center of the opening,
a length of the electron emission material protruding from the opening is smaller than 200 μm, and
the diameter L and the angle θ satisfy a relationship of 2.69×10 7×L2+3.64 ×10 4×L−2.21×10 2≤log θ≤1.27×10 6×L2−4.18×10 4×L+1.45, the diameter L being expressed in units of μm, and the angle θ being expressed in units of degrees (°).

10. The electron source according to claim 1 , wherein
the receding portion includes a tapered portion forming an angle θ with a surface perpendicular to the central axis,
at least a part of the tapered portion is disposed within a diameter L from the center of the opening,
a length of the electron emission material protruding from the opening is larger than 300 μm, and
the diameter L and the angle θ satisfy a relationship of 2.59×10 7×L2+1.82 ×10 4×L−6.04×10 1≤log θ<5.15×10 7×L2−2.29×10 4×L+8.10×10 1, the diameter L being expressed in units of μm, and the angle θ being expressed in units of degrees (°).

11. An electron gun comprising:
the electron source according to claim 1 .

12. A charged particle beam device comprising:
the electron source according to claim 1 or the electron gun according to claim 11 .

13. An electron source comprising:
a suppressor electrode having an opening at one end portion thereof in a direction along a central axis; and
an electron emission material having a distal end protruding from the opening, wherein
the suppressor electrode further includes a receding portion receding to a position farther from the distal end of the electron emission material than the end portion of the suppressor electrode in the direction along the central axis at a position in an outer peripheral direction than the opening, and
the receding portion includes a tapered portion having at least two or more different angles formed with a surface perpendicular to the central axis.

14. An electron gun comprising:
the electron source according to claim 13 .

15. A charged particle beam device comprising:
the electron source according to claim 13 .

16. An electron source comprising:
a suppressor electrode having an opening at one end portion thereof in a direction along a central axis; and
an electron emission material having a distal end protruding from the opening, wherein
the suppressor electrode further includes a receding portion receding to a position farther from the distal end of the electron emission material than the end portion of the suppressor electrode in the direction along the central axis at a position in an outer peripheral direction than the opening,
the receding portion includes a tapered portion forming an angle θ with a surface perpendicular to the central axis,
at least a part of the tapered portion is disposed within a diameter L from a center of the opening, and
the diameter L and the angle θ satisfy a relationship of 2.40×10 7×L2+3.18 ×10 4×L−4.08×10 1≤log θ≤6.68×10 7×L2−2.68×10 4×L+1.08, the diameter L being expressed in units of μm, and the angle θ being expressed in units of degrees (°).

17. An electron source comprising:
a suppressor electrode having an opening at one end portion thereof in a direction along a central axis; and
an electron emission material having a distal end protruding from the opening, wherein
the suppressor electrode further includes a receding portion receding to a position farther from the distal end of the electron emission material than the end portion of the suppressor electrode in the direction along the central axis at a position in an outer peripheral direction than the opening,
at least a part of the receding portion is disposed within a diameter L from a center of the opening,
the electron emission material protrudes from the opening by a length T, and
the diameter L and the length T satisfy a relationship of L=3.53T+1607, both the diameter L and the length T being expressed in units of μm.

Assignees

• Hitachi High Tech Corp

Inventors

• Kasuya Keigo
• Ishikawa Shuhei
• Tanimoto Kenji
• Doi Takashi
• Matsunaga Soichiro
• Morita Hiroshi
• KOMESU Daigo
• Miyata Kenji

Classifications

• H01J37/28

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

• H01J37/073

  Electron guns using field emission, photo emission, or secondary emission electron sources · CPC title

• H01J37/3174

  Particle-beam lithography, e.g. electron beam lithography · CPC title

• H01J1/46

  Control electrodes, e.g. grid (for igniting arrangements H01J7/30); Auxiliary electrodes (auxiliary anodes for maintaining a discharge H01J1/36) · CPC title

• H01J1/3044

  Point emitters · CPC title