# US 2018/0021920 A1 · Method of monitoring a dressing process and polishing apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0021920 A1 - Document ID: US20180021920A1 - Status: Published application - Kind: A1 - Application number: 15/721,211 - Filed: 2017-09-29 - Published: 2018-01-25 - Earliest claimed: 2012-08-28 - Assignees: Ebara Corporation - Applicants: Ebara Corporation - Inventors: Hiroyuki SHINOZAKI - Web page: https://patentgrep.com/patent/US20180021920A1 ## CPC - B24B 49/18: taking regard of the presence of dressing tools - B24B 49/16: taking regard of the load - 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 ## Abstract A method of monitoring dressing of a polishing pad is provided. The method includes: rotating a polishing table that supports the polishing pad; dressing the polishing pad by pressing a dresser against the polishing pad while causing the dresser to oscillate in a radial direction of the polishing pad; calculating a work coefficient representing a ratio of a frictional force between the dresser and the polishing pad to a force of pressing the dresser against the polishing pad; and monitoring dressing of the polishing pad based on the work coefficient. ## Claims ### Claim 1 A method of monitoring dressing of a polishing pad, said method comprising: rotating a polishing table that supports the polishing pad; dressing the polishing pad by pressing a dresser against the polishing pad while causing the dresser to oscillate in a radial direction of the polishing pad; during dressing of the polishing pad, calculating a work of the dresser from a horizontal force exerted on the dresser and a travel distance of the dresser in a circumferential direction of the polishing pad; calculating a power of the dresser from the horizontal force and the travel distance of the dresser in the circumferential direction of the polishing pad per unit time; and determining a remaining life of the dresser based on the work of the dresser and the power of the dresser. ### Claim 2 (depends on 1) The method according to claim 1, wherein: the work is calculated from a product of the horizontal force and the travel distance of the dresser in the circumferential direction of the polishing pad, and the power is calculated from a product of the horizontal force and the travel distance of the dresser in the circumferential direction of the polishing pad per unit time. ### Claim 3 (depends on 1) The method according to claim 1, wherein the remaining life of the dresser is determined by Tend=(W0−W1)/P, where Tend represents the remaining life, W0 represents an allowable total work of the dresser, W1 is a cumulative work of the dresser, and P represents the power. ### Claim 4 (depends on 1) The method according to claim 1, wherein the travel distance is calculated from a distance of the dresser from a center of the polishing table and the rotational speed of the polishing table. ### Claim 5 A method of monitoring dressing of a polishing pad, said method comprising: rotating a polishing table that supports the polishing pad; dressing the polishing pad by pressing a dresser against the polishing pad while causing the dresser to oscillate in a radial direction of the polishing pad; during dressing of the polishing pad, calculating a work of the dresser from a horizontal force exerted on the dresser and a travel distance of the dresser in a circumferential direction of the polishing pad; calculating a power of the dresser from the horizontal force and the travel distance of the dresser in the circumferential direction of the polishing pad per unit time; calculating a moving average of the power in a predetermined time interval; and determining a remaining life of the dresser based on the work of the dresser and the moving average of the power of the dresser. ### Claim 6 (depends on 5) The method according to claim 5, wherein: the work is calculated from a product of the horizontal force and the travel distance of the dresser in the circumferential direction of the polishing pad, and the power is calculated from a product of the horizontal force and the travel distance of the dresser in the circumferential direction of the polishing pad per unit time. ### Claim 7 (depends on 5) The method according to claim 5, wherein the remaining life of the dresser is determined by Tend=(W0−W1)/P, where Tend represents the remaining life, W0 represents an allowable total work of the dresser, W1 is a cumulative work of the dresser, and P represents the moving average of the power. ### Claim 8 (depends on 5) The method according to claim 5, wherein the travel distance is calculated from a distance of the dresser from a center of the polishing table and the rotational speed of the polishing table. ### Claim 9 A polishing apparatus for polishing a substrate, comprising: a polishing table that supports a polishing pad; a table motor configured to rotate the polishing table; a dresser configured to dress the polishing pad; a swing motor configured to cause the dresser to oscillate in a radial direction of the polishing pad; a pressing device configured to press the dresser against the polishing pad; and a pad monitoring device configured to monitor dressing of the polishing pad, the pad monitoring device being configured to calculate a work of the dresser from a horizontal force exerted on the dresser and a travel distance of the dresser in a circumferential direction of the polishing pad; calculate a power of the dresser from the horizontal force and the travel distance of the dresser in the circumferential direction of the polishing pad per unit time; and determine a remaining life of the dresser based on the work of the dresser and the power of the dresser. ### Claim 10 (depends on 9) The polishing apparatus according to claim 9, wherein the pad monitoring device is configured to calculate the work from a product of the horizontal force and the travel distance of the dresser in the circumferential direction of the polishing pad, and to calculate the power from a product of the horizontal force and the travel distance of the dresser in the circumferential direction of the polishing pad per unit time. ### Claim 11 (depends on 9) The polishing apparatus according to claim 9, wherein the pad monitoring device is configured to determine the remaining life of the dresser by Tend=(W0−W1)/P, where Tend represents the remaining life, W0 represents an allowable total work of the dresser, W1 is a cumulative work of the dresser, and P represents the power. ### Claim 12 (depends on 9) The polishing apparatus according to claim 9, wherein the pad monitoring device is configured to calculate the travel distance from a distance of the dresser from a center of the polishing table and the rotational speed of the polishing table. ### Claim 13 A polishing apparatus for polishing a substrate, comprising: a polishing table that supports a polishing pad; a table motor configured to rotate the polishing table; a dresser configured to dress the polishing pad; a swing motor configured to cause the dresser to oscillate in a radial direction of the polishing pad; a pressing device configured to press the dresser against the polishing pad; and a pad monitoring device configured to monitor dressing of the polishing pad, the pad monitoring device being configured to calculate a work of the dresser from a horizontal force exerted on the dresser and a travel distance of the dresser in a circumferential direction of the polishing pad; calculate a power of the dresser from the horizontal force and the travel distance of the dresser in the circumferential direction of the polishing pad per unit time; calculate a moving average of the power in a predetermined time interval; and determine a remaining life of the dresser based on the work of the dresser and the moving average of the power of the dresser. ### Claim 14 (depends on 13) The polishing apparatus according to claim 13, wherein the pad monitoring device is configured to calculate the work from a product of the horizontal force and the travel distance of the dresser in the circumferential direction of the polishing pad, and to calculate the power from a product of the horizontal force and the travel distance of the dresser in the circumferential direction of the polishing pad per unit time. ### Claim 15 (depends on 13) The polishing apparatus according to claim 13, wherein the pad monitoring device is configured to determine the remaining life of the dresser by Tend=(W0−W1)/P, where Tend represents the remaining life, W0 represents an allowable total work of the dresser, W1 is a cumulative work of the dresser, and P represents the moving average of the power. ### Claim 16 (depends on 13) The polishing apparatus according to claim 13, wherein the pad monitoring device is configured to calculate the travel distance from a distance of the dresser from a center of the polishing table and the rotational speed of the polishing table.