System for electron beam detection

Patent metadata

Field	Value
Publication number	US-9778186-B2
Application number	US-201514686308-A
Country	US
Kind code	B2
Filing date	Apr 14, 2015
Priority date	Apr 15, 2014
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

An electron beam detection apparatus includes a first aperture element including a first set of apertures. The apparatus includes a second aperture element including a second set of apertures. The second set of apertures is arranged in a pattern corresponding with the pattern of the first plurality of apertures. The detection apparatus includes an electron-photon conversion element configured to receive electrons of the electron beam transmitted through the first and second aperture elements. The electron-photon conversion element is configured to generate photons in response to the received electrons. The detection apparatus includes an optical assembly including one or more optical elements. The detection apparatus includes a detector assembly. The optical elements of the optical assembly are configured to direct the generated photons from the electron-photon conversion system to the detector assembly.

First claim

The invention claimed is:

1. An apparatus for electron beam detection comprising:
a first aperture element including a first plurality of apertures;
a second aperture element including a second plurality of apertures, the second plurality of apertures arranged in a pattern corresponding with the pattern of the first plurality of apertures;
a scintillator element configured to receive electrons of the patterned electron beam transmitted through the first aperture element and the second aperture element, wherein the scintillator element is configured to generate light in response to the received electrons;
an optical guide assembly; and
a light detector configured to measure a light signal from the scintillator element, wherein the optical guide assembly is configured to direct light generated by the scintillator element to the light detector, at least a portion of a path defined by the optical guide assembly is parallel to a surface of a sample, wherein the light detector is positioned at an edge portion of the sample.

2. The apparatus of claim 1 , further comprising:
a controller configured to determine a position of the electron beam based on the light signal measured by the light detector.

3. The apparatus of claim 1 , wherein the optical guide assembly comprises:
a light guide element configured to guide light generated by the scintillator element to the light detector.

4. The apparatus of claim 3 , further comprising:
a collimator arranged at an output portion of the light guide and configured to collimate the light guided to the output portion of the light guide.

5. The apparatus of claim 4 , wherein the light guide element is configured to transmit light from the output of the light guide to the light detector via free space coupling.

6. The apparatus of claim 1 , wherein the optical guide assembly comprises:
a plurality of light guide elements, wherein each light guide element is optically coupled to an aperture of the second plurality of apertures.

7. The apparatus of claim 6 , wherein each light guide element is configured to guide light from an aperture of the second plurality of apertures to one of a plurality of channels of the light detector.

8. The apparatus of claim 1 , wherein the optical guide assembly comprises:
a first planar mirror; and
a second planar mirror, wherein the first planar mirror and the second planar mirror are arranged to direct the light from the scintillator element to the light detector.

9. The apparatus of claim 8 , further comprising:
one or more lens elements.

10. The apparatus of claim 1 , wherein the optical guide assembly comprises:
a first curved mirror; and
a second curved mirror, wherein the first curved mirror and the second curved mirror are arranged to direct the light from the scintillator element to the light detector.

11. The apparatus of claim 1 , wherein the optical guide assembly is disposed on a sample stage.

12. The apparatus of claim 11 , wherein the light detector is positioned proximate to an outside edge portion of the sample stage.

13. The apparatus of claim 11 , wherein the sample stage is disposed within a vacuum chamber.

14. The apparatus of claim 13 , further comprising:
an optical receiver assembly configured to receive light from the optical guide assembly and transmit the light through a window of the vacuum chamber and to the light detector, wherein the light detector is positioned outside of the vacuum chamber.

15. The apparatus of claim 1 , wherein the electron beam is a patterned electron beam.

16. The apparatus of claim 1 , wherein the light detector comprises:
a photomultiplier tube.

17. The apparatus of claim 1 , wherein the light detector comprises:
a multi-channel photomultiplier tube.

18. The apparatus of claim 1 , wherein the light detector comprises:
an array of photomultiplier tubes.

19. The apparatus of claim 1 , wherein the light detector comprises:
a diode sensor.

20. The apparatus of claim 1 , wherein the light detector comprises:
a segment diode sensor.

21. The apparatus of claim 1 , wherein the light detector comprises:
a charge-coupled device detector.

22. An apparatus for electron beam detection comprising:
a scattering element including a plurality of pillar structures configured to scatter electrons of the electron beam;
a scintillator element configured to receive electrons scattered from the plurality of pillar structures of the scattering element, wherein the scintillator element is configured to generate light in response to the received scattered electrons;
an optical guide assembly; and
a light detector configured to measure a light signal from the scintillator element, wherein the optical guide assembly is configured to direct light generated by the scintillator element to the light, at least a portion of a path defined by the optical guide assembly is parallel to a surface of a sample, wherein the light detector is positioned at an edge portion of the sample.

23. The apparatus of claim 22 , further comprising:
a controller configured to determine a position of the electron beam based on the light signal measured by the light detector.

24. The apparatus of claim 22 , wherein the plurality of pillar structures are embedded in a substrate.

25. The apparatus of claim 22 , wherein at least some of the pillar structures are formed from metal.

26. The apparatus of claim 22 , further comprising:
a Faraday cup configured to collect electrons scattered from the plurality of pillar structures; and
a current meter electrically coupled to the Faraday cup and configured to determine a number of electrons collected by the Faraday cup based on the measured current from the Faraday cup.

27. The apparatus of claim 22 , wherein the electron beam is a patterned electron beam.

28. An electron-optical system with patterned electron beam detection comprising:
an electron-optical sub-system configured to generate an electron beam;
a sample stage configured to secure a sample; and
an electron beam detection assembly disposed on the sample stage comprising:
a first aperture element including a first plurality of apertures;
a second aperture element including a second plurality of apertures, the second plurality of apertures arranged in a pattern corresponding with the pattern of the first plurality of apertures;
a scintillator element configured to receive electrons of the electron beam transmitted through the first aperture element and the second aperture element, wherein the scintillator element is configured to generate light in response to the received electrons;
an optical guide assembly; and
a light detector configured to measure a light signal from the scintillator element, wherein the optical guide assembly is configured to direct light generated by the scintillator to the light detector assembly.

29. The electron-optical system of claim 28 , further comprising:
a controller configured to determine a position of the electron beam based on the light signal measured by the light detector, wherein the controller is further configured to adjust a position of the electron beam generate by the electron-optical sub-system based on the determined position of the electron beam.

30. The electron-optical system of claim 28 , further comprising:
a vacuum chamber, wherein the s

Assignees

• Kla Tencor Corp

Inventors

• Kojima Shinichi
• Wahba Hamada
• Gluszczak Michael R
• Diregolo Joseph A

Classifications

• H01J37/244 Primary

  Detectors; Associated components or circuits therefor · CPC title

• H01J37/226

  Optical arrangements for illuminating the object; optical arrangements for collecting light from the object · CPC title

• H01J2237/2443

  Scintillation detectors · CPC title

• H01J2237/043

  Beam blanking · CPC title

• H01J2237/24578

  Spatial variables, e.g. position, distance · CPC title