# US 2019/0378705 A1 · High Resolution Electron Energy Analyzer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0378705 A1 - Document ID: US20190378705A1 - Status: Published application - Kind: A1 - Application number: 16/298,755 - Filed: 2019-03-11 - Published: 2019-12-12 - Earliest claimed: 2018-06-06 - Assignees: KLA-Tencor Corporation - Applicants: KLA-Tencor Corporation - Inventors: Xinrong Jiang; Christopher Sears; Nikolai Chubun - Web page: https://patentgrep.com/patent/US20190378705A1 ## CPC - H01J 49/48: using electrostatic analysers, e.g. cylindrical sector, Wien filter - H01J 37/05: Electron or ion-optical arrangements for separating electrons or ions according to their energy {or mass}(particle separator tubes H01J49/00) - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) ## 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. ## Claims ### Claim 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. ### Claim 2 (depends on 1) The electron energy analyzer of claim 1, wherein the electrostatic lens comprises a unipotential electrostatic lens. ### Claim 3 (depends on 1) 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. ### Claim 4 (depends on 1) The electron energy analyzer of claim 1, further comprising 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. ### Claim 5 (depends on 4) The electron energy analyzer of claim 4, wherein directing the electron beam to the energy-analyzing field region comprises focusing the electron beam 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. ### Claim 6 (depends on 4) The electron energy analyzer of claim 4, wherein the size of the second electron beam crossover is smaller than the size of the energy-analyzing field region. ### Claim 7 (depends on 1) 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. ### Claim 8 (depends on 7) The electron energy analyzer of claim 7, wherein the electron-optical element comprises an anode. ### Claim 9 (depends on 1) The electron energy analyzer of claim 1, wherein the energy-analyzing field region has a diameter between 0.9 and 2.1 microns. ### Claim 10 (depends on 1) The electron energy analyzer of claim 1, wherein the electrostatic lens comprises an Einzel lens. ### Claim 11 (depends on 1) 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. ### Claim 12 (depends on 1) The electron energy analyzer of claim 1, wherein the electron detector comprises a Faraday cup. ### Claim 13 (depends on 1) 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. ### Claim 14 (depends on 1) 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. ### Claim 15 (depends on 1) The electron energy analyzer of claim 1, wherein the electron energy analyzer is disposed within an optical column of an electron beam apparatus. ### Claim 16 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. ### Claim 17 (depends on 16) The system of claim 16, wherein the electrostatic lens comprises a unipotential electrostatic lens. ### Claim 18 (depends on 16) The system of claim 16, 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. ### Claim 19 (depends on 16) The system of claim 16, wherein the magnetic lens is configured to focus the electron beam to a first electron beam crossover, wherein the first electron beam crossover is disposed between the electron source and the electrostatic lens. ### Claim 20 (depends on 19) The system of claim 19, wherein directing the electron beam to the energy-analyzing field region comprises focusing the electron beam 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. ### Claim 21 (depends on 19) The system of claim 19, wherein the size of the second electron beam crossover is smaller than the size of the energy-analyzing field region. ### Claim 22 (depends on 16) The system of claim 16, further comprising an electron-optical element configured to accelerate the electrons of the electron beam toward the electrostatic lens. ### Claim 23 (depends on 22) The system of claim 22, wherein the electron-optical element comprises an anode. ### Claim 24 (depends on 16) The system of claim 16, wherein the energy-analyzing field region has a diameter between 0.9 and 2.1 microns. ### Claim 25 (depends on 16) The system of claim 16, wherein the electrostatic lens comprises an Einzel lens. ### Claim 26 (depends on 16) The system of claim 16, 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. ### Claim 27 (depends on 16) The system of claim 16, wherein the electron detector comprises a Faraday cup. ### Claim 28 (depends on 16) The system of claim 16, wherein an electron path from the electron source to the electron detector comprises a substantially linear electron path. ### Claim 29 (depends on 16) The system of claim 16, 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. ### Claim 30 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; and generating, with the electron detector, one or more signals based on the received electrons. ### Claim 31 A method, comprising: receiving, at a plurality of working voltages of an electrostatic lens and a first magnetic excitation level of a magnetic lens, electrons passed through an energy-analyzing field region with an electron detector; receiving, at a plurality of working voltages of the electrostatic lens and an additional magnetic excitation level of the magnetic lens, electrons passed through the energy-analyzing field region with the electron detector; calculating a first electron energy resolution of an energy analyzer at the first magnetic excitation level and an additional electron energy resolution at the additional magnetic excitation level; and analyzing electron-energy spread of an electron source with the electron analyzer operating at the magnetic excitation level with the highest electron-energy resolution. ### Claim 32 (depends on 31) The method of claim 31, wherein receiving, at a plurality of working voltages of an electrostatic lens and a first magnetic excitation level of a magnetic lens, electrons passed through an energy-analyzing field region with an electron detector comprises: directing an electron beam to a magnetic lens of an electron analyzer at the first magnetic excitation level; directing the electron beam from the magnetic lens to an energy-analyzing field region of an electrostatic lens generated with a first working voltage; receiving, with an electron detector, electrons passed through the energy-analyzing field region with the first magnetic excitation level and the first working voltage; directing the electron beam from the magnetic lens to the energy-analyzing field region of the electrostatic lens generated with an additional working voltage; and receiving, with the electron detector, electrons passed through the energy-analyzing field region with the first magnetic excitation level and the additional working voltage. ### Claim 33 (depends on 31) The method of claim 31, wherein receiving, at a plurality of working voltages of an electrostatic lens and an additional magnetic excitation level of the magnetic lens, electrons passed through the energy-analyzing field region with the electron detector comprises: directing an electron beam to a magnetic lens of an electron analyzer at an additional magnetic excitation level; directing the electron beam from the magnetic lens to an energy-analyzing field region of an electrostatic lens generated with a first working voltage; receiving, with an electron detector, the electrons passed through the energy-analyzing field region with the additional magnetic excitation level and the first working voltage; directing the electron beam from the magnetic lens to the energy-analyzing field region of the electrostatic lens generated with an additional working voltage; and receiving, with the electron detector, electrons passed through the energy-analyzing field region with the additional magnetic excitation level and the additional working voltage.