# US 12,191,109 B2 · Sample pre-charging methods and apparatuses for charged particle beam inspection > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,191,109 B2 - Document ID: US12191109B2 - Status: Granted - Kind: B2 - Application number: 18/144,821 - Filed: 2023-05-08 - Published: 2023-11-09 - Granted: 2025-01-07 - Earliest claimed: 2017-09-29 - Assignees: ASML Netherlands B.V. - Applicants: ASML Netherlands B.V. - Inventors: Xuedong Liu; Qingpo Xi; Youfei Jiang; Weiming Ren; Xuerang Hu; Zhongwei Chen - Web page: https://patentgrep.com/patent/US12191109B2 ## CPC - H01J 37/02: Details - H01J 37/12: electrostatic - H01J 37/04: Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement or ion-optical arrangement {(H01J37/32009, H01J37/32623, H01J37/3266, H01J37/32697 take precedence; electron or ion-optical systems for localised treatment of objects H01J37/3007)} - H01J 37/28: with scanning beams {(H01J37/268, H01J37/292, H01J37/2955 take precedence)} - H01J 2237/0041: Neutralising arrangements - H01J 2237/0048: Charging arrangements - H01J 2237/2817: Pattern inspection - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) ## Abstract Disclosed herein is an apparatus comprising: a source of charged particles configured to emit a beam of charged particles along a primary beam axis of the apparatus; a condenser lens configured to cause the beam to concentrate around the primary beam axis; an aperture; a first multi-pole lens; a second multi-pole lens; wherein the first multi-pole lens is downstream with respect to the condenser lens and upstream with respect to the second multi-pole lens; wherein the second multi-pole lens is downstream with respect to the first multi-pole lens and upstream with respect to the aperture. ## Claims ### Claim 1 An apparatus comprising: an electron source configured to emit an electron beam along a primary beam axis of the apparatus; a condenser lens configured to cause the electron beam to concentrate around the primary beam axis; an aperture; a first multi-pole lens; and a second multi-pole lens, wherein the first and the second multi-pole lenses are configured to adjust a current of the electron beam to be incident on a sample by adjusting a portion of the electron beam passing through the aperture. ### Claim 2 (depends on 1) The apparatus of claim 1, further comprising a scanning deflector configured to scan the beam relative to a sample. ### Claim 3 (depends on 1) The apparatus of claim 1, further comprising an objective lens configured to focus the beam onto a sample. ### Claim 4 (depends on 1) The apparatus of claim 1, further comprising a third multi-pole lens and a fourth multi-pole lens, wherein the third multi-pole lens is downstream with respect to the aperture, and wherein the fourth multi-pole lens is downstream with respect to the third multi-pole lens. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the first multi-pole lens and the second multi-pole lens are electrostatic lenses. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the first multi-pole lens and the second multi-pole lens each have at least four poles. ### Claim 7 (depends on 6) The apparatus of claim 6, wherein the poles each have a cross-sectional shape of a section of a ring. ### Claim 8 (depends on 6) The apparatus of claim 6, wherein the poles are prismatic or cylindrical. ### Claim 9 (depends on 6) The apparatus of claim 6, wherein each of the poles is separated from its neighbors by a gap or by a dielectric. ### Claim 10 (depends on 6) The apparatus of claim 6, wherein the poles are configured to have different electric voltages applied thereto. ### Claim 11 (depends on 1) The apparatus of claim 1, wherein the first multi-pole lens is configured to stretch the electron beam in a first direction and to compress the electron beam in a second direction, and wherein the second multi-pole lens is configured to stretch the electron beam in the second direction and to compress the electron beam in the first direction. ### Claim 12 (depends on 1) The apparatus of claim 1, wherein the portion of the electron beam passing through the aperture is based on an activation state of the first multi-pole lens and the second multi-pole lens. ### Claim 13 (depends on 12) The apparatus of claim 12, wherein the first multi-pole lens and the second multi-pole lens are configured to be activated such that substantially all of the electron beam is allowed to pass through the aperture. ### Claim 14 A non-transitory computer readable medium that stores a set of instructions that is executable by at least one processor of a computer system to cause the computer system to perform operations for imaging a sample using an apparatus comprising a source of charged particles, a condenser lens, an aperture, a first multi-pole lens, and a second multi-pole lens, the operations comprising: setting a beam of charged particles into a first configuration suitable for pre-charging the sample; pre-charging an area of the sample using the beam of charged particles in the first configuration; setting the beam of charged particles into a second configuration suitable for imaging the sample; configuring the first and the second multi-pole lenses to adjust a current of the beam of charged particles to be incident on the sample by adjusting a portion of the beam of charged particles passing through the aperture; and imaging the area using the beam of charged particles in the second configuration. ### Claim 15 (depends on 14) The non-transitory computer readable medium of claim 14, wherein the operations further comprise setting the beam of charged particles into the first configuration by energizing the first multi-pole lens and the second multi-pole lens of the apparatus. ### Claim 16 (depends on 14) The non-transitory computer readable medium of claim 14, wherein the operations further comprise setting the beam of charged particles into the second configuration by de-energizing at least one of the first multi-pole lens and the second multi-pole lens of the apparatus. ### Claim 17 (depends on 14) The non-transitory computer readable medium of claim 14, wherein the portion of the electron beam passing through the aperture is based on an activation state of the first multi-pole lens and the second multi-pole lens. ### Claim 18 (depends on 15) The non-transitory computer readable medium of claim 15, wherein energizing the first and the second multi-pole lens allows substantially all of the beam of charged particles to pass through the aperture. ### Claim 19 A method for imaging a sample using an apparatus comprising a source of charged particles, a condenser lens, an aperture, a first multi-pole lens, and a second multi-pole lens, the method comprising: setting a beam of charged particles into a first configuration suitable for pre-charging a sample; pre-charging an area of the sample using the beam of charged particles in the first configuration; setting the beam of charged particles into a second configuration suitable for imaging the sample; configuring the first and the second multi-pole lenses to adjust a current of the beam of charged particles to be incident on the sample by adjusting a portion of the beam of charged particles passing through the aperture; and imaging the area using the beam of charged particles in the second configuration.