Tilt-column multi-beam electron microscopy system and method

Patent metadata

Field	Value
Publication number	US-12068129-B2
Application number	US-202217981141-A
Country	US
Kind code	B2
Filing date	Nov 4, 2022
Priority date	Nov 4, 2022
Publication date	Aug 20, 2024
Grant date	Aug 20, 2024

Abstract

A system and method of a tilt-column electron beam imaging system is disclosed. The system may include an imaging sub-system. The imaging sub-system may include a plurality of electron beam sources configured to generate a plurality of beamlets. The imaging sub-system may further include a plurality of tilt-illumination columns, where a respective tilt-illumination column is configured to receive a respective beamlet from a respective electron beam source. For the system and method, a first tilt axis of a first tilt-illumination column may be orientated along a first angle and at least one additional tilt axis of at least one additional tilt-illumination column may be orientated along at least one additional angle different from the first angle, where each of the plurality of beamlets pass through a first common crossover volume.

First claim

What is claimed:

1. A tilt-column electron beam imaging system comprising:
an imaging sub-system comprising:
a plurality of electron beam sources configured to generate a plurality of beamlets to simultaneously probe a plurality of measurement regions on a sample;
a collection pathway comprising one or more detectors; and
an illumination pathway comprising:
a plurality of tilt-illumination columns, wherein a respective tilt-illumination column is configured to receive a respective beamlet from a respective electron beam source, wherein the respective tilt-illumination column comprises:
a set of one or more electron optics configured to adjust the respective beamlet,

wherein a first tilt axis of a first tilt-illumination column is orientated along a first angle and at least one additional tilt axis of at least one additional tilt-illumination column is orientated along at least one additional angle different from the first angle, wherein each of the plurality of beamlets pass through a first common crossover volume.

2. The tilt-column electron beam imaging system of claim 1 , wherein each electron beam source comprises one or more electron source emitter tips.

3. The tilt-column electron beam imaging system of claim 1 , wherein each of the plurality of tilt-illumination columns comprises a gun lens.

4. The tilt-column electron beam imaging system of claim 1 , wherein each of the plurality of tilt-illumination columns comprises a condenser lens.

5. The tilt-column electron beam imaging system of claim 1 , wherein each of the plurality of tilt-illumination columns comprises a modulator, wherein the modulator is configured to at least one of deflect the respective beamlet or adjust the respective beamlet.

6. The tilt-column electron beam imaging system of claim 1 , wherein each of the plurality of tilt-illumination columns comprises a beam limiting aperture.

7. The tilt-column electron beam imaging system of claim 6 , wherein the beam limiting aperture is located before a gun lens relative to a direction of propagation of the respective beamlet.

8. The tilt-column electron beam imaging system of claim 1 , wherein each of the plurality of tilt-illumination columns comprises a secondary beam limiting aperture.

9. The tilt-column electron beam imaging system of claim 8 , wherein the secondary beam limiting aperture is located after a gun lens.

10. The tilt-column electron beam imaging system of claim 1 , wherein the illumination pathway further comprises a global transfer lens configured to direct each of the plurality of beamlets from a diverging path to a converging path and towards a second common crossover volume, wherein the global transfer lens is located after the first common crossover volume.

11. The tilt-column electron beam imaging system of claim 1 , wherein the illumination pathway further comprises a global condenser lens configured to adjust an intermediate image plane of the plurality of beamlets.

12. The tilt-column electron beam imaging system of claim 11 , wherein the global condenser lens overlaps with the first common crossover volume.

13. The tilt-column electron beam imaging system of claim 1 , wherein the illumination pathway further comprises a global objective lens configured to direct each of the plurality of beamlets to be telecentrically formed on the sample.

14. The tilt-column electron beam imaging system of claim 1 , wherein the collection pathway further comprises a Wien filter configured to separate primary electrons from secondary electrons.

15. The tilt-column electron beam imaging system of claim 1 , wherein the plurality of tilt-illumination columns comprises a plurality of double-tilt-illumination columns, wherein each double-tilt-illumination column comprises a modulator, wherein the beamlet of each double-tilt-illumination column is directed, via the modulator, from being orientated along a first double-tilt axis to a second double-tilt axis.

16. The tilt-column electron beam imaging system of claim 1 , wherein the illumination pathway further comprises a central illumination column comprising a central electron beam source configured to generate a central beamlet along a central axis of the imaging sub-system.

17. The tilt-column electron beam imaging system of claim 1 , wherein the plurality of tilt-illumination columns are arranged in an array.

18. The tilt-column electron beam imaging system of claim 17 , wherein the array is a spherical array.

19. The tilt-column electron beam imaging system of claim 17 , wherein the array is a hexagonal array.

20. The tilt-column electron beam imaging system of claim 1 , wherein at least a portion of the set of the one or more electron optics are arranged in a set of layered arrays, wherein the set of layered arrays comprises:
a beam limiting aperture array layer;
a gun lens array layer; and
an electrically grounded layer.

21. The tilt-column electron beam imaging system of claim 1 , wherein each modulator is arranged in a modulator array.

22. The tilt-column electron beam imaging system of claim 1 , wherein each electron beam source is arranged in an electron beam source array.

23. The tilt-column electron beam imaging system of claim 1 , wherein the plurality of tilt-illumination columns are radially arranged.

24. The tilt-column electron beam imaging system of claim 1 , wherein the plurality of beamlets are radially arranged normal to a 3-dimensional curved plane.

25. The tilt-column electron beam imaging system of claim 24 , wherein the 3-dimensional curved plane is a portion of a sphere.

26. A method comprising:
generating electrons of a plurality of beamlets using a plurality of electron beam sources;
adjusting each beamlet with respective electron optics of a respective tilt-illumination column configured to receive the beamlet from a respective electron beam source;
simultaneously illuminating a plurality of measurement regions of a sample with the plurality of beamlets;
collecting secondary electrons emanating from the plurality of measurement regions of the sample using a detector; and
detecting the secondary electrons using the detector,
wherein a first tilt axis of a first tilt-illumination column is orientated along a first angle and at least one additional tilt axis of at least one additional tilt-illumination column is orientated along at least one additional angle different from the first angle, wherein each of the plurality of beamlets pass through a first common crossover volume.

27. The method of claim 26 further comprising determining one or more characteristics of the sample based on the detecting of the secondary electrons.

28. The method of claim 26 further comprising adjusting the beamlets using a global condenser lens configured to adjust an intermediate image plane of the plurality of beamlets.

29. The method of claim 26 , wherein each tilt-illumination column includes a modulator, wherein each beamlet is directed, via the modulator, from being orientated along a respective first double-tilt axis to a respective second double-tilt axis.

Assignees

• Kla Corp

Inventors

• Jiang Xinrong
• Jiang Youfei
• Nyffenegger Ralph
• Steigerwald Michael

Classifications

• H01J37/261

  Details · CPC title

• H01J2237/15

  Means for deflecting or directing discharge · CPC title

• H01J2237/153

  Correcting image defects, e.g. stigmators · CPC title

• H01J2237/0492

  Lens systems · CPC title

• H01J37/28 Primary

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