# US 11,110,565 B2 · Polishing apparatus, polishing method, and polishing control apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,110,565 B2 - Document ID: US11110565B2 - Status: Granted - Kind: B2 - Application number: 15/909,634 - Filed: 2018-03-01 - Published: 2019-03-14 - Granted: 2021-09-07 - Earliest claimed: 2017-09-08 - Assignees: Toshiba Memory Corporation - Applicants: Toshiba Memory Corporation - Inventors: Syunichi Ono; Tsutomu Miki - Web page: https://patentgrep.com/patent/US11110565B2 ## CPC - B24B 49/003: {involving acoustic means} - B24B 37/013: Devices or means for detecting lapping completion - B24B 37/042: {operating processes therefor} - B24B 49/04: involving measurement of the workpiece at the place of grinding during grinding operation - B24B 49/10: involving electrical means (B24B49/02, B24B49/08 take precedence) - B24B 49/16: taking regard of the load - B24B 53/017: Devices or means for dressing, cleaning or otherwise conditioning lapping tools - G01B 17/08: for measuring roughness or irregularity of surfaces - B24B: MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING (grinding of gear teeth B23F, of screw-threads B23G1/36; by electro-erosion B23H; abrasive or related blasting B24C; tools for grinding, buffing or sharpening B24D; polishing compositions C09G1/00; abrasives C09K3/14; electrolytic etching or polishing C25F3/00; grinding arrangements for use on assembled railway tracks E01B31/17); DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS ## Abstract A polishing apparatus includes an acoustic sensor, a sound collector, an analyzer, a feature quantity calculator, and an end point calculator. The acoustic sensor detects the polishing sound of an object. The sound collector collects a polishing sound detected by the acoustic sensor. The analyzer performs frequency analysis on the power spectrum of the polishing sound with a predetermined time resolution. The feature quantity calculator calculates an arithmetic value of the power spectra having a preset time difference of the power spectra as a polishing feature quantity by using the analysis data provided by the analysis performed by the analyzer. The end point calculator determines a polishing end point of the object based on the change in the feature quantity. ## Claims ### Claim 1 A polishing apparatus comprising: an acoustic sensor configured to detect a polishing sound of an object to be polished; a sound collector configured to collect the polishing sound detected by the acoustic sensor; an analyzer configured to perform frequency analysis on power spectra of the polishing sound with a given time resolution to acquire first data, the first data represented by a first table in which each power spectrum of the power spectra is correlated with a time point and a frequency; a calculator configured to: perform an arithmetic operation between a first part of the power spectra in the first data that is correlated with a first time point and a second part of the power spectra in the first data that is correlated with a second time point to acquire second data, the second data represented by a second table in which each of a plurality of arithmetic values is correlated with the time point and a mixed frequency; analyze each of parts of the arithmetic values in the second data that is correlated with a corresponding mixed frequency to determine whether or not the part of the arithmetic values of the second data satisfies a changes in value; synthesize two of the parts of the arithmetic values of the second data with value changes when a correlation coefficient between the two of the parts of the arithmetic values of the second data with value changes falls under a threshold value to obtain synthesized values; and an end point calculator configured to determine a polishing end point of the object based on a change in the synthesized values. ### Claim 2 (depends on 1) The polishing apparatus according to claim 1, wherein the calculator is configured to set the first time point and the second time point to have a time difference based on polishing environment information relating to a polishing environment of the object. ### Claim 3 (depends on 2) The polishing apparatus according to claim 2, wherein the polishing environment information includes replacement timing of a polishing component. ### Claim 4 (depends on 1) The polishing apparatus according to claim 1, wherein the calculator is configured to calculate a product of the power spectra of different frequencies. ### Claim 5 (depends on 1) The polishing apparatus according to claim 1, wherein the time difference is set based on a decrease time of the power spectrum. ### Claim 6 (depends on 1) The polishing apparatus according to claim 1, wherein the calculator is configured to calculate the correlation coefficient if the second data changes from increasing to decreasing. ### Claim 7 A polishing method comprising: detecting a polishing sound of an object to be polished; collecting the polishing sound; performing frequency analysis on a power spectra of the collected polishing sound with a given time resolution to acquire first data, the first data represented by a first table in which each power spectrum of the power spectra is correlated with a time point and a frequency; performing an arithmetic operation between a first part of the power spectra in the first data that is correlated with a first time point and a second part of the power spectra in the first data that is correlated with a second time point to acquire second data, the second data represented by a second table in which each of a plurality of arithmetic values is correlated with the time point and a mixed frequency; analyzing each of parts of the arithmetic values in the second data that is correlated with a corresponding mixed frequency to determine whether or not the part of the arithmetic values of the second data satisfies changes in value; synthesizing two of the parts of the arithmetic values of the second data with value changes when a correlation coefficient between the two of the parts of the arithmetic values of the second data with value changes falls under a threshold value to obtain synthesized values; and determining a polishing end point of the object based on a change in the synthesized values. ### Claim 8 (depends on 7) The method according to claim 7, further comprising setting the first time point and the second time point to have a time difference based on polishing environment information indicative of a polishing environment of the object. ### Claim 9 (depends on 7) The method according to claim 7, wherein the time difference is set based on a decrease time of the power spectrum. ### Claim 10 (depends on 7) The method according to claim 7, wherein the correlation coefficient is calculated in a case where the second data changes from increasing to decreasing. ### Claim 11 A polishing control apparatus comprising: a processor and a memory storing data, the processor configured to: collect a polishing sound of an object to be polished; perform frequency analysis on the power spectra of the polishing sound with a given time resolution to acquire first data, the first data represented by a first table in which each power spectrum of the power spectra is correlated with a time point and a frequency; perform an arithmetic operation between a first part of the power spectra in the first data that is correlated with a first time point and a second part of the power spectra in the first data that is correlated with a second time point to acquire second data, the second data represented by a second table in which each of a plurality of arithmetic values is correlated with the time point and a mixed frequency; analyze each of parts of the arithmetic values in the second data that is correlated with a corresponding mixed frequency to determine whether or not the part of the arithmetic values of the second data satisfies changes in value; synthesize two of the parts of the arithmetic values of the second data with value changes when a correlation coefficient between the two of the parts of the arithmetic values of the second data with value changes falls under a threshold value to obtain synthesized values; and determine a polishing end point of the object to be polished based on a change in the synthesized values. ### Claim 12 (depends on 11) The polishing control apparatus according to claim 11, wherein the processor is configured to set the first time point and the second time point to have a time difference based on polishing environment information indicative of a polishing environment of the object to be polished. ### Claim 13 (depends on 11) The polishing control apparatus according to claim 11, wherein the time difference is set based on a decrease time of the power spectrum. ### Claim 14 (depends on 11) The polishing control apparatus according to claim 11, wherein the processor is configured to calculate the correlation coefficient in a case where the second data changes from increasing to decreasing.