# US 2025/0164408 A1 · Position feedback sensor using out-of-band wavelengths > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2025/0164408 A1 - Document ID: US20250164408A1 - Status: Published application - Kind: A1 - Application number: 18/941,459 - Filed: 2024-11-08 - Published: 2025-05-22 - Earliest claimed: 2023-11-21 - Applicants: Kla Corporation - Inventors: Florian Melsheimer; Lauren Wilson; Alon Rosenthal; Matthew Hoffman - Web page: https://patentgrep.com/patent/US20250164408A1 ## CPC - G01N 21/8806: {Specially adapted optical and illumination features} - G01J 1/4228: {arrangements with two or more detectors, e.g. for sensitivity compensation} - G01J 1/44: Electric circuits {(for command of an exposure part G03B7/02)} - G01J 3/0289: {Field-of-view determination; Aiming or pointing of a spectrometer; Adjusting alignment; Encoding angular position; Size of measurement area; Position tracking} - G01N 21/01: Arrangements or apparatus for facilitating the optical investigation - G02B 26/0808: {by means of one or more diffracting elements} - G02B 26/0816: {by means of one or more reflecting elements} - G05D 3/12: using feedback - G01B 11/026: {by measuring distance between sensor and object (G01B11/0608 takes precedence)} - G01B 21/16: for measuring distance of clearance between spaced objects - G01J 2001/446: {Photodiode} - G01N 2021/0106: {General arrangement of respective parts} - G01N 2201/061: Sources - G01N 2201/127: Calibration; base line adjustment; drift compensation - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS ## Abstract An assembly is in a path of a beam of light, which has a first and second spectral components at different wavelengths. A first spectral component and a second spectral component of the beam of light are projected through an aperture. A sensor is disposed around the aperture to only receive a second spectral component of the beam of light. A position of the beam of light relative to the aperture can be determined using information from the sensor. ## Claims ### Claim 1 A system comprising: an assembly in a path of a beam of light, wherein the assembly defines an aperture in the assembly, wherein a first spectral component and a second spectral component of the beam of light are projected through the aperture, and wherein the first spectral component and the second spectral component have different wavelengths; a sensor that defines four sensor sections disposed around the aperture, wherein the sensor is positioned to primarily receive a second spectral component of the beam of light; and a processor in electronic communication with the sensor, wherein the processor is configured to determine a position of the beam of light relative to the aperture using information from the sensor. ### Claim 2 (depends on 1) The system of claim 1, further comprising a plasma light source that generates the light. ### Claim 3 (depends on 1) The system of claim 1, wherein the sensor sections are each a photodiode, a photocathode, or a thermocouple. ### Claim 4 (depends on 1) The system of claim 1, wherein each of the sensor sections is disposed on the assembly adjacent to the aperture. ### Claim 5 (depends on 1) The system of claim 1, further comprising a plurality of reflective elements disposed on the assembly adjacent to the aperture, wherein each of the reflective elements reflects the part of the second spectral component to a corresponding one of the sensor sections. ### Claim 6 (depends on 1) The system of claim 1, further comprising a diffractive element disposed in a path of the beam of light, wherein the diffractive element directs the first spectral component through the aperture and the part of the second spectral component to the sensor sections. ### Claim 7 (depends on 1) The system of claim 1, wherein the first spectral component has a wavelength of 13.5 nm. ### Claim 8 (depends on 1) The system of claim 1, wherein the second spectral component has a longer wavelength than the first spectral component. ### Claim 9 (depends on 1) The system of claim 1, wherein the first spectral component is inside the second spectral component. ### Claim 10 A method comprising: directing a beam of light at an aperture of an assembly, wherein the beam of light includes a first spectral component and a second spectral component, and wherein at least the first spectral component is directed through the aperture, wherein the first spectral component and the second spectral component have different wavelengths; receiving primarily the second spectral component at a plurality of sensor sections; and determining, using a processor, a position of the beam of light relative to the aperture using information from the sensor sections. ### Claim 11 (depends on 10) The method of claim 10, further comprising generating the beam of light with a plasma light source. ### Claim 12 (depends on 10) The method of claim 10, wherein the sensor sections are each a photodiode, a photocathode, or a thermocouple. ### Claim 13 (depends on 10) The method of claim 10, wherein each of the sensor sections is disposed on the assembly adjacent to the aperture. ### Claim 14 (depends on 10) The method of claim 10, further comprising reflecting part of the second spectral component to the sensor sections with a plurality of reflective elements, wherein the plurality of reflective elements are disposed on the assembly adjacent to the aperture. ### Claim 15 (depends on 10) The method of claim 10, further comprising diffracting the beam of light using a diffractive element disposed in a path of the beam of light thereby directing the first spectral component through the aperture and the part of the second spectral component to the sensor sections. ### Claim 16 (depends on 10) The method of claim 10, wherein the first spectral component has a wavelength of 13.5 nm. ### Claim 17 (depends on 10) The method of claim 10, wherein the second spectral component has a longer wavelength than the first spectral component. ### Claim 18 (depends on 10) The method of claim 10, further comprising sending instructions, using the processor, to adjust a position of the beam of light based on the position.