# US 12,002,698 B2 · Metrology apparatus and method based on diffraction using oblique illumination and method of manufacturing semiconductor device using the metrology method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,002,698 B2 - Document ID: US12002698B2 - Status: Granted - Kind: B2 - Application number: 17/174,731 - Filed: 2021-02-12 - Published: 2022-01-06 - Granted: 2024-06-04 - Earliest claimed: 2020-07-06 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Samsung Electronics Co., Ltd. - Inventors: Myungjun Lee; Changhyeong Yoon; Wookrae Kim; Jaehwang Jung; Jinseob Kim - Web page: https://patentgrep.com/patent/US12002698B2 ## CPC - G03F 7/70616: {Monitoring the printed patterns} - H10P 72/0616: {Monitoring of warpages, curvatures, damages, defects or the like} - G01N 21/4788: {Diffraction (for sizing particles G01N15/0205)} - G01N 21/8851: {Scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment, for detecting different kinds of defects, for compensating for structures, markings, edges (G01N21/8806 and G01N21/93 - G01N21/95692 take precedence; optical measurement of dimensions G01B11/00; optical scanning G02B26/10; image transformation G06T3/00; computerised image enhancement G06T5/00; image processing per se for flaw detection G06T7/0002)} - G01N 21/9501: {Semiconductor wafers (manufacturing processes per se of semiconductor devices implementing a measuring step H10P74/20)} - G03F 7/70633: {Overlay, i.e. relative alignment between patterns printed by separate exposures in different layers, or in the same layer in multiple exposures or stitching} - G01N 2201/021: Special mounting in general - G01N 2201/0636: Reflectors - G06N 20/00: Machine learning - G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G) - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 - 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) - G06N: COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS ## Abstract Provided are a diffraction-based metrology apparatus having high measurement sensitivity, a diffraction-based metrology method capable of accurately performing measurement on a semiconductor device, and a method of manufacturing a semiconductor device using the metrology method. The diffraction-based metrology apparatus includes a light source that outputs a light beam, a stage on which an object is placed, a reflective optical element that irradiates the light beam onto the object through reflection, such that the light beam is incident on the object at an inclination angle, the inclination angle being an acute angle, a detector that detects a diffracted light beam that is based on the light beam reflected and diffracted by the object and a processor that measures a 3D pupil matrix for the diffracted light beam and analyze the object based on the 3D pupil matrix. ## Claims ### Claim 1 An apparatus comprising: a light source configured to output a light beam; a stage on which an object is placed; a reflective optical element configured to irradiate the light beam onto the object through reflection, such that the light beam is incident on the object at an inclination angle, the inclination angle being an acute angle; a detector configured to detect a diffracted light beam that is based on the light beam reflected and diffracted by the object; an angle adjuster; and a processor configured to measure a 3D pupil matrix for the diffracted light beam and analyze the object based on the 3D pupil matrix, wherein the reflective optical element comprises a magnification reflection type object lens, the magnification reflection type object lens comprising a first aspherical mirror having an opening at a center and a second aspherical mirror provided below the first aspherical mirror, wherein the light beam passes through the opening of the first aspherical mirror from a first side of the first aspherical mirror, is reflected by the second aspherical mirror, is incident on a second side of the first aspherical mirror different from the first side of the first aspherical mirror, is reflected by the first aspherical mirror, and is incident on the object at the inclination angle, and wherein the angle adjuster is further configured to adjust the inclination angle to expand a wavelength range of the light beam by changing a focusing position of the light beam on a pupil plane between the first aspherical mirror and the second aspherical mirror, such that sensitivity is maximized for a wavelength used the measurement of the 3D pupil matrix. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the light beam output by the light source is a broadband light beam within the wavelength range from 180 nm to 20,000 nm. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein the light source is further configured to output the light beam while scanning the wavelength range with a short wavelength or output the light beam including an entirety of the wavelength range. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the angle adjuster comprises one of a mirror type, a wavefront adjustment type, or a translation type. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the detector is further configured to detect a pupil image, which is an image on the pupil plane. ### Claim 6 (depends on 5) The apparatus of claim 5, wherein the 3D pupil matrix comprises the wavelength of the light beam, the inclination angle, and intensity of the diffracted light beam on the pupil image as variables. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the processor is further configured to analyze the object by performing regression or machine learning, based on data of the 3D pupil matrix. ### Claim 8 (depends on 1) The apparatus of claim 1, wherein the processor is further configured to analyze at least one of an overlay error of the object, a size of a pattern, a thickness of the pattern, a uniformity of the pattern, or a defect. ### Claim 9 (depends on 1) The apparatus of claim 1, wherein the processor is further configured to analyze an overlay error of the object, and wherein the wavelength of the light beam is selected and the inclination angle is adjusted, such that measurement sensitivity for the overlay error is maximized. ### Claim 10 (depends on 1) The apparatus of claim 1, wherein the processor is further configured to analyze an overlay error of the object, wherein measurement sensitivity for the overlay error is defined as a difference between intensity of a positive first-order light beam and a negative first-order light beam of the diffracted light beam, wherein the measurement sensitivity comprises a left bias sensitivity in a case where a bias is applied to the left of an overlay mark and a right bias sensitivity in a case where the bias is applied to the right of the overlay mark, and when an overlay error curve is defined as a graph of the right bias sensitivity Δ1+with respect to the left bias sensitivity according to the wavelength, and wherein the processor is further configured to determine whether the overlay mark is asymmetric by using the overlay error curve. ### Claim 11 (depends on 10) The apparatus of claim 10, wherein, when the overlay error curve is linear or the overlay error curve is non-linear and satisfies a set criteria, the processor is further configured to analyze the overlay error through regression or machine learning based on data of the 3D pupil matrix, and wherein when the overlay error curve is non-linear and does not satisfy the set criteria, processing conditions for the overlay mark are changed. ### Claim 12 An apparatus comprising: a light source configured to output a light beam; a stage on which an object is placed; a reflective optical element configured to irradiate the light beam onto the object through reflection, such that the light beam is incident on the object at an inclination angle, the inclination angle being an acute angle; an angle adjuster configured to adjust the inclination angle; a detector configured to detect a diffracted light beam based on the light beam reflected and diffracted by the object, wherein a pupil image, which is an image formed on a pupil plane of the diffracted light beam, is detected; and a processor configured to measure a 3D pupil matrix for the diffracted light beam, which comprises a wavelength of the light beam, the inclination angle, and intensity of the diffracted light beam as variables, and analyze an overlay error of the object based on the 3D pupil matrix, wherein the reflective optical element comprises a magnification reflection type object lens, the magnification reflection type object lens comprising a first aspherical mirror having an opening at a center and a second aspherical mirror provided below the first aspherical mirror, wherein the light beam passes through the opening of the first aspherical mirror from a first side of the first aspherical mirror, is reflected by the second aspherical mirror, is incident on a second side of the first aspherical mirror different from the first side of the first aspherical mirror, is reflected by the first aspherical mirror, and is incident on the object at the inclination angle, and wherein the angle adjuster is further configured to adjust the inclination angle to expand a wavelength range of the light beam by changing a focusing position of the light beam on a pupil plane between the first aspherical mirror and the second aspherical mirror, such that sensitivity is maximized for a wavelength used the measurement of the 3D pupil matrix. ### Claim 13 (depends on 12) The apparatus of claim 12, wherein the light beam output by the light source is a broadband light beam within the wavelength range from 180 nm to 20,000 nm, and the light source is further configured to output the light beam while scanning the wavelength range with a short wavelength or output the light beam including an entirety of the wavelength range. ### Claim 14 (depends on 12) The apparatus of claim 12, wherein measurement sensitivity for the overlay error is defined as a difference between intensity of a positive first-order light beam and a negative first-order light beam of the diffracted light beam, wherein the measurement sensitivity comprises a left bias sensitivity in a case where a bias is applied to the left of an overlay mark and a right bias sensitivity in a case where the bias is applied to the right of the overlay mark, and when an overlay error curve is defined as a graph of the right bias sensitivity with respect to the left bias sensitivity according to the wavelength, and wherein the processor is further configured to determine whether the overlay mark is asymmetric by using the overlay error curve. ### Claim 15 (depends on 14) The apparatus of claim 14, wherein, when the overlay error curve is linear or the overlay error curve is non-linear and satisfies a set criteria, the processor is further configured to analyze the overlay error through regression or machine learning based on data of the 3D pupil matrix, and wherein when the overlay error curve is non-linear and does not satisfy the set criteria, processing conditions for the overlay mark are changed. ### Claim 16 An apparatus comprising: a memory storing one or more instructions; and a processor configured to: control a light source to output a light beam, the light beam being irradiated onto the object at an inclination angle through a reflective optical element comprising a magnification reflection type object lens, the magnification reflection type object lens comprising a first aspherical mirror having an opening at a center and a second aspherical mirror provided below the first aspherical mirror; receive detected information corresponding to a diffracted light beam that is based on the light beam reflected and diffracted by an object; measure a 3D pupil matrix for the diffracted light beam based on the detected information; and analyze the object based on the 3D pupil matrix, wherein the light beam passes through the opening of the first aspherical mirror from a first side of the first aspherical mirror, is reflected by the second aspherical mirror, is incident on a second side of the first aspherical mirror different from the first side of the first aspherical mirror, is reflected by the first aspherical mirror, and is incident on the object at the inclination angle, and wherein the angle adjuster is further configured to adjust the inclination angle to expand a wavelength range of the light beam by changing a focusing position of the light beam on a pupil plane between the first aspherical mirror and the second aspherical mirror, such that sensitivity is maximized for a wavelength used the measurement of the 3D pupil matrix.