Particle beam system and the use thereof for flexibly setting the current intensity of individual particle beams

Patent metadata

Field	Value
Publication number	US-12119204-B2
Application number	US-202217573222-A
Country	US
Kind code	B2
Filing date	Jan 11, 2022
Priority date	Jul 31, 2019
Publication date	Oct 15, 2024
Grant date	Oct 15, 2024

Abstract

A particle beam system and, such as a multi-beam particle microscope, can have a current intensity of individual particle beams that is flexibly set over large value ranges without structural modifications. The particle beam system can include a condenser lens system, a pre-multi-lens array with a specific pre-counter electrode and a pre-multi-aperture plate, and a multi-lens array. The system can includes a controller to supply adjustable excitations to the condenser lens system and the pre-counter electrode so that the charged particles are incident on the pre-multi-aperture plate in telecentric manner.

First claim

What is claimed is:

1. A particle beam system, comprising:
a particle source configured to generate a divergent beam of charged particles having a beam path through the particle beam system;
a condenser lens system configured so that the beam of charged particles passes through the condenser lens during use of the particle beam system;
a pre-multi-lens array comprising a pre-counter electrode and a pre-multi-aperture plate, the pre-counter electrode comprising a central opening through which the beam of charged particles passes during use of the particle beam system, the pre-multi-aperture plate being arranged in the beam path downstream of the pre-counter electrode, the pre-multi-aperture plate being arranged so that the charged particles pass therethrough in the form of a multiplicity of charged individual particle beams during use of the particle beam system;
a multi-lens array in the beam path downstream of the pre-multi-lens array, the multi-lens array comprising a multi-aperture plate and a counter electrode, the multi-aperture plate comprising a multiplicity of openings through which at least a portion of the charged individual particle beams pass during use of the particle beam system, and the counter electrode comprising a central opening disposed in the beam path downstream of the multi-aperture plate, the counter electrode being substantially passed through by the multiplicity of individual particle beams during use of the particle beam system; and
a controller configured to supply adjustable excitations to the condenser lens system and the pre-counter electrode to control a current intensity of the individual particle beams so that, during use of the particle beam system, the beam of charged particles enters a global lens field of the pre-counter electrode in a convergent fashion or a divergent fashion and the beam of charged particles is incident on the pre-multi-aperture plate in telecentric fashion.

2. The particle beam system of claim 1 , wherein the controller is configured to set a current intensity of the individual particle beams.

3. The particle beam system of claim 1 , comprising a micro-optical unit comprising the multi-lens array.

4. The particle beam system of claim 3 , wherein the micro-optical unit comprises a frame at ground potential.

5. The particle beam system of claim 3 , wherein the micro-optical unit comprises the pre-multi-aperture plate.

6. The particle beam system of claim 1 , further comprising a pre-auxiliary electrode comprising a central opening in the beam path downstream of the pre-counter electrode and just upstream of the pre-multi-aperture plate, wherein the controller is configured to supply an adjustable voltage to the central opening of the pre-auxiliary electrode.

7. The particle beam system of claim 1 , further comprising a post-auxiliary electrode comprising a central opening in the beam path just downstream of the multi-aperture plate and upstream of the counter electrode, wherein the controller is configured to supply an adjustable voltage to the central opening of the post-auxiliary electrode.

8. The particle beam system of claim 1 , wherein the condenser lens system comprises two condenser lenses.

9. The particle beam system of claim 8 , wherein both condenser lenses are magnetic condenser lenses.

10. The particle beam system of claim 1 , wherein:
the condenser lens system comprises a magnetic condenser lens and an electrostatic condenser lens;
the electrostatic condenser lens is in the beam path downstream of the magnetic condenser lens;
the particle beam system comprises a booster electrode between the magnetic condenser lens and the electrostatic condenser lens;
the controller is configured to drive the booster electrode; and
the booster electrode is configured to excite the electrostatic condenser lens.

11. The particle beam system of claim 1 , further comprising a beam current-restricting multi-aperture plate system comprising a beam current-restricting multi-aperture plate which comprises a multiplicity of openings, wherein the beam current-restricting multi-aperture plate system is insertable into the beam path downstream of the pre-multi-lens array and upstream of the multi-lens array.

12. The particle beam system of claim 11 , wherein the beam current-restricting multi-aperture plate system comprises two or more beam current-restricting multi-aperture plates which are displaceable in substantially parallel fashion relative to one another, each with a multiplicity of openings, so that an effective multi-aperture plate opening size is adjustable for the individual particle beams passing through the beam current-restricting multi-aperture plate system during use of the particle beam system.

13. The particle beam system of claim 12 , wherein the openings of the beam current-restricting multi-aperture plates are circular or square.

14. The particle beam system of claim 11 , wherein:
the beam current-restricting multi-aperture plate system comprises two beam current-restricting multi-aperture plates disposed sequentially in the beam path, each with a multiplicity of openings; and
the particle beam system comprises two deflectors between the two beam current-restricting multi-aperture plates;
the two deflectors are drivable to parallelly displace individual particle beams with respect to an optical axis when the individual particle beams pass through the multi-aperture plate system during use of the particle beam system.

15. The particle beam system of claim 11 , wherein the openings of the beam current-restricting multi-aperture plate have substantially the same size and geometric form.

16. The particle beam system of claim 11 , wherein the openings of the beam current-restricting multi-aperture plate are circular and/or annular.

17. The particle beam system of claim 1 , wherein:
the particle beam system has an intermediate image plane downstream of the multi-lens array in a direction of the beam path;
real foci of the individual particle beams are formed in the intermediate image plane during use of the particle beam system;
the foci are spaced apart by a pitch in the intermediate image plane;
the particle beam system comprises a field lens system downstream of the multi-lens array in the direction of the beam path;
the particle beam system comprises an objective lens downstream of the field lens system in the direction of the beam path;
the particle beam system has an object plane in which the individual particle beams are imaged particle-optically during use of the particle beam system; and
the individual particle beams are spaced apart by a pitch in the object plane.

18. The particle beam system of claim 17 , wherein the controller is configured to control the particle beam system to set the pitch in the object plane.

19. The particle beam system of claim 17 , wherein the controller is configured to control the particle beam system to set a numerical aperture in the object plane to optimize a resolution in the object plane for a beam current of the individual particle beams.

20. A method, comprising:
using the particle beam system of claim 1 to: a) set a current intensity of individual particle beams; or b) set a resolution in an object plane of the particle beam system.

21. A microscope, comprising:
the particle beam system according to claim 1 ,
wherein the microscope is a multi-beam particle microscope.

Assignees

• Carl Zeiss Multisem Gmbh

Inventors

• Schubert Stefan
• Zeidler Dirk
• Metalidis Georgo
• Fritz Hans
• Lenke Ralf

Classifications

• H01J2237/04926

  combined · CPC title

• H01J37/263

  Contrast, resolution or power of penetration · CPC title

• H01J37/145

  Combinations of electrostatic and magnetic lenses · CPC title

• H01J2237/0453

  multiple apertures · CPC title

• H01J37/3023

  Program control · CPC title