Multi-beam charged particle system

Patent metadata

Field	Value
Publication number	US-11087948-B2
Application number	US-202016940863-A
Country	US
Kind code	B2
Filing date	Jul 28, 2020
Priority date	Feb 4, 2019
Publication date	Aug 10, 2021
Grant date	Aug 10, 2021

Abstract

A multi-beam charged particle system includes: a vacuum enclosure having an opening covered by a door; a particle source configured to generate charged particles, wherein the particle source is arranged within the vacuum enclosure; at least one multi-aperture plate module including at least one multi-aperture plate and a base; and a transfer box having an opening covered by a door. The at least one multi-aperture plate includes a plurality of apertures. The base is configured to hold the at least one multi-aperture plate. The base is configured to be fixed relative to the vacuum enclosure such that the multi-aperture plate module is arranged in an interior of the vacuum enclosure such that, during operation of the particle beam system, particles traverse the plural multi-aperture plates through the apertures of the plates.

First claim

What is claimed is:

1. A multi-beam charged particle system, comprising:
a particle source configured to generate charged particles;
a multi-aperture plate module comprising a multi-aperture plate; and
a vacuum enclosure having an interior in which a vacuum is maintainable,
wherein:
the vacuum enclosure comprises a plurality of vacuum spaces connected by tubes;
the plurality of vacuum spaces comprises first, second and third vacuum spaces;
the first vacuum space houses the particle source;
the second vacuum space is configured to house an object stage;
the third vacuum space is configured to house an electron detector; and
the multi-beam charged particle system is configured so that, during use of the multi-beam charged article system when the object stage is in the second vacuum space and an object is mounted on the object stage, the multi-aperture plate generates a plurality of particle beams from charged particles traversing apertures of the multi-aperture plate and the plurality of particle beams enter the second vacuum space to be incident on the object.

2. The multi-beam charged particle system of claim 1 , further comprising the object stage housed in the second vacuum space.

3. The multi-beam charged particle system of claim 2 , further comprising the electron detector housed in the third vacuum space.

4. The multi-beam charged particle system of claim 1 , further comprising the electron detector housed in the third vacuum space.

5. The multi-beam charged particle system of claim 1 , wherein the vacuum enclosure comprises a plurality of connecting ports connectable to a pump system configured to evacuate each of the first, second and third vacuum spaces.

6. The multi-beam charged particle system of claim 5 , further comprising the pump system.

7. The multi-beam charged particle system of claim 1 , wherein:
the plurality of vacuum spaces further comprises a fourth vacuum space to house the multi-aperture plate;
the first vacuum space is connected to the fourth vacuum space via a first tube; and
the fourth vacuum space is connected to the second vacuum space via a second tube.

8. The multi-beam charged particle system of claim 7 , further comprising at least one shutter configured to selectively open and close and to break a vacuum in the fourth vacuum space without breaking a vacuum in the first vacuum space.

9. The multi-beam charged particle system of claim 8 , wherein the at least one shutter comprises a first shutter between the third and fourth vacuum spaces.

10. The multi-beam charged particle system of claim 9 , wherein the at least one shutter further comprises a second shutter configured to transfer the multi-aperture plate module in and out of the fourth vacuum space.

11. The multi-beam charged particle system of claim 7 , wherein the second tube comprises a first section traversing a beam splitter and a second section traversing an objective lens.

12. The multi-beam charged particle system of claim 11 , wherein the second vacuum space is connected with the third vacuum space via a third tube and the second section of the second tube.

13. The multi-beam charged particle system of claim 12 , wherein the third tube is integrally formed with the second tube.

14. The multi-beam charged particle system of claim 7 , further comprising a condenser lens, wherein the first tube traverses the condenser lens.

15. The multi-beam charged particle system of claim 1 , wherein each of the tubes comprises a contiguous wall free of perforations having a cross section greater than 25 square millimeters.

16. The multi-beam charged particle system of claim 1 , wherein, for each tube:
the tube includes a tube section having a length L in millimeters;
a cross-section of the tube is less than an area F in square millimeters at each position along the tube section; and
F/L< 10.

17. The multi-beam charged particle system of claim 16 , wherein, for at least one of the tubes, F/L<5.

18. The multi-beam charged particle system of claim 16 , wherein, for at least one of the tubes, F/L<2.

19. A multi-beam charged particle system, comprising:
a particle source configured to generate charged particles;
a multi-aperture plate module comprising a multi-aperture plate;
an electron detector;
an object stage;
a vacuum enclosure; and
a pump system,
wherein:
the vacuum enclosure comprises a plurality of vacuum spaces connected by tubes;
the plurality of vacuum spaces comprises first, second and third vacuum spaces;
the first vacuum space houses the particle source;
the second vacuum space houses the object stage;
the third vacuum space houses the electron detector;
the vacuum system is configured to evacuate each of the first, second and third vacuum spaces; and
the multi-beam charged particle system is configured so that, during use of the multi-beam charged article system when an object is mounted on the object stage, the multi-aperture plate generates a plurality of particle beams from charged particles traversing apertures of the multi-aperture plate and the plurality of particle beams enter the second vacuum space to be incident on the object.

20. The multi-beam charged particle system of claim 19 , wherein:
the plurality of vacuum spaces further comprises a fourth vacuum space to house the multi-aperture plate;
the first vacuum space is connected to the fourth vacuum space via a first tube;
the fourth vacuum space is connected to the second vacuum space via a second tube;
the multi-beam charged particle source further comprises first and second shutters;
the first shutter is between the third and fourth vacuum spaces;
the second shutter is configured to transfer the multi-aperture plate module in and out of the fourth vacuum space;
the second tube comprises a first section traversing a beam splitter and a second section traversing an objective lens;
the second vacuum space is connected with the third vacuum space via a third tube and the second section of the second tube;
the third tube is integrally formed with the second tube;
the multi-beam charged particle source further comprises a condenser lens; and
the first tube traverses the condenser lens.

Assignees

• Carl Zeiss Multisem Gmbh

Inventors

• Zeidler Dirk
• Kemen Thomas
• Riedesel Christof
• Lenke Ralf
• Jacobi Joerg

Classifications

• H01J2237/2817

  Pattern inspection · CPC title

• H01J2237/1202

  Associated circuits · CPC title

• H01J37/18 Primary

  Vacuum locks {; Means for obtaining or maintaining the desired pressure within the vessel} · CPC title

• H01J37/09

  Diaphragms; Shields associated with electron or ion-optical arrangements; Compensation of disturbing fields · CPC title

• H01J37/10 Primary

  Lenses · CPC title