High resolution electron energy analyzer

Patent metadata

Field	Value
Publication number	US-10964522-B2
Application number	US-201916298755-A
Country	US
Kind code	B2
Filing date	Mar 11, 2019
Priority date	Jun 6, 2018
Publication date	Mar 30, 2021
Grant date	Mar 30, 2021

Abstract

A high-resolution electron energy analyzer is disclosed. In one embodiment, the electron energy analyzer includes an electrostatic lens configured to generate an energy-analyzing field region, decelerate electrons of an electron beam generated by an electron source, and direct the decelerated electrons of the electron beam to the energy-analyzing field region. In another embodiment, the electron energy analyzer includes an electron detector configured to receive one or more electrons passed through the energy-analyzing field region. In another embodiment, the electron detector is further configured to generate one or more signals based on the one or more received electrons.

First claim

What is claimed:

1. A high-resolution electron energy analyzer, comprising:
an electrostatic lens configured to:
generate an energy-analyzing field region;
decelerate electrons of an electron beam generated by an electron source;
direct the decelerated electrons of the electron beam to the energy-analyzing field region; and

an electron detector configured to receive one or more electrons passed through the energy-analyzing field region, wherein the electron detector is further configured to generate one or more signals based on the one or more received electrons; and
a magnetic lens configured to focus the electron beam from the electron source to a first electron beam crossover, wherein the first electron beam crossover is disposed between the electron source and the electrostatic lens, wherein the electron beam is focused to a second electron beam crossover, wherein the second electron beam crossover is disposed between the first electron beam crossover and the energy-analyzing field region.

2. The electron energy analyzer of claim 1 , wherein the electrostatic lens comprises a unipotential electrostatic lens.

3. The electron energy analyzer of claim 1 , further comprising a controller communicatively coupled to the electron detector, wherein the controller is configured to determine an energy spread of the electron source based on the one or more signals from the electron detector.

4. The electron energy analyzer of claim 1 , wherein the size of the second electron beam crossover is smaller than the size of the energy-analyzing field region.

5. The electron energy analyzer of claim 1 , further comprising an electron-optical element configured to accelerate the electrons of the electron beam toward the electrostatic lens.

6. The electron energy analyzer of claim 5 , wherein the electron-optical element comprises an anode.

7. The electron energy analyzer of claim 1 , wherein the energy-analyzing field region has a diameter between 0.9 and 2.1 microns.

8. The electron energy analyzer of claim 1 , wherein the electrostatic lens comprises an Einzel lens.

9. The electron energy analyzer of claim 1 , further comprising one or more apertures disposed between the electron source and the energy-analyzing field region, wherein the one or more apertures are configured to modify one or more characteristics of the electron beam.

10. The electron energy analyzer of claim 1 , wherein the electron detector comprises a Faraday cup.

11. The electron energy analyzer of claim 1 , wherein an electron path from the electron source to the electron detector comprises a substantially linear electron path.

12. The electron energy analyzer of claim 1 , wherein the electrostatic lens is configured to decelerate the electrons of the electron beam generated by the electron source by retarding the electrons of the electron beam to energy levels substantially equivalent to initial emission energy levels of the electrons.

13. The electron energy analyzer of claim 1 , wherein the electron energy analyzer is disposed within an optical column of an electron beam apparatus.

14. A system, comprising:
an electron source configured to generate an electron beam;
a magnetic lens configured to receive the electron beam;
an electrostatic lens configured to:
generate an energy-analyzing field region;
decelerate electrons of the electron beam; and
direct the decelerated electrons of the electron beam to the energy-analyzing field region; and

an electron detector configured to receive one or more electrons passed through the energy-analyzing field region, wherein the electron detector is further configured to generate one or more signals based on the one or more received electrons, wherein the magnetic lens is configured to focus the electron beam from the electron source to a first electron beam crossover, wherein the first electron beam crossover is disposed between the electron source and the electrostatic lens, wherein the electron beam is focused to a second electron beam crossover, wherein the second electron beam crossover is disposed between the first electron beam crossover and the energy-analyzing field region.

15. The system of claim 14 , wherein the electrostatic lens comprises a unipotential electrostatic lens.

16. The system of claim 14 , further comprising a controller communicatively coupled to the electron detector, wherein the controller is configured to determine an energy spread of the electron source based on the one or more signals from the electron detector.

17. The system of claim 14 , wherein the size of the second electron beam crossover is smaller than the size of the energy-analyzing field region.

18. The system of claim 14 , further comprising an electron-optical element configured to accelerate the electrons of the electron beam toward the electrostatic lens.

19. The system of claim 18 , wherein the electron-optical element comprises an anode.

20. The system of claim 14 , wherein the energy-analyzing field region has a diameter between 0.9 and 2.1 microns.

21. The system of claim 14 , wherein the electrostatic lens comprises an Einzel lens.

22. The system of claim 14 , further comprising one or more apertures disposed between the electron source and the energy-analyzing field region, wherein the one or more apertures are configured to modify one or more characteristics of the electron beam.

23. The system of claim 14 , wherein the electron detector comprises a Faraday cup.

24. The system of claim 14 , wherein an electron path from the electron source to the electron detector comprises a substantially linear electron path.

25. The system of claim 14 , wherein the electrostatic lens is configured to decelerate the electrons of the electron beam generated by the electron source by retarding the electrons of the electron beam to energy levels substantially equivalent to initial emission energy levels of the electrons.

26. A method of analyzing electron energies, comprising:
generating an energy-analyzing field region with a unipotential electrostatic lens;
decelerating electrons of an electron beam generated by an electron source;
directing the electrons of the electron beam to the energy-analyzing field region of the unipotential electrostatic lens;
receiving electrons which passed through the energy-analyzing field region with an electron detector;
generating, with the electron detector, one or more signals based on the received electrons; and
focusing the electron beam from the electron source to a first electron beam crossover with a magnetic lens, wherein the first electron beam crossover is disposed between the electron source and the electrostatic lens, wherein the electron beam is focused to a second electron beam crossover, wherein the second electron beam crossover is disposed between the first electron beam crossover and the energy-analyzing field region.

Assignees

• Kla Tencor Corp
• Kla Corp

Inventors

• Jiang Xinrong
• Sears Christopher
• Chubun Nikolai

Classifications

• H01J37/14

  magnetic · CPC title

• H01J37/12 Primary

  electrostatic · CPC title

• H01J49/48 Primary

  using electrostatic analysers, e.g. cylindrical sector, Wien filter · CPC title

• H01J37/05

  Electron or ion-optical arrangements for separating electrons or ions according to their energy {or mass}(particle separator tubes H01J49/00) · CPC title