# US 10,121,640 B2 · Method and apparatus for plasma processing > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,121,640 B2 - Document ID: US10121640B2 - Status: Granted - Kind: B2 - Application number: 14/603,187 - Filed: 2015-01-22 - Published: 2015-06-18 - Granted: 2018-11-06 - Earliest claimed: 2013-04-09 - Assignees: Hitachi High-Technologies Corporation - Applicants: Hitachi High-Technologies Corporation - Inventors: Satoru Muto; Tetsuo Ono; Yasuo Ohgoshi; Hirofumi Eitoku - Web page: https://patentgrep.com/patent/US10121640B2 ## CPC - H01J 37/32137: {controlling of the discharge by modulation of energy} - H01J 37/32082: {Radio frequency generated discharge (H01J37/32357, H01J37/32366, H01J37/32394 and H01J37/32403 take precedence)} - H01J 37/32146: {Amplitude modulation, includes pulsing} - H01J 37/32165: {Plural frequencies} - H01J 37/32532: {Electrodes} - H01J 37/32715: {Workpiece holder} - H10P 50/242: {of Group IV materials} - H10P 50/268: {of silicon-containing layers} - H10P 50/283: {by chemical means} - H10P 72/0421: {for drying etching} - H01J 2237/334: Etching - H10D 30/024: {of fin field-effect transistors [FinFET]} - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES ## Abstract The present invention provides a plasma processing method that uses a plasma processing apparatus including a plasma processing chamber in which a sample is plasma processed, a first radio-frequency power supply that supplies a first radio-frequency power for generating plasma, and a second radio-frequency power supply that supplies a second radio-frequency power to a sample stage on which the sample is mounted, wherein the plasma processing method includes the steps of modulating the first radio-frequency power by a first pulse; and controlling a plasma dissociation state to create a desired dissociation state by gradually controlling a duty ratio of the first pulse as a plasma processing time elapses. ## Claims ### Claim 1 A plasma processing apparatus comprising: a plasma processing chamber to contain a sample to be processed; a first radio-frequency power supply to supply a first radio-frequency power to generate plasma; a second radio-frequency power supply to supply a second radio-frequency power to a sample stage configured to support the sample; a first pulse generator to generate a first pulse to modulate the first radio-frequency power; and a control unit configured to retain the first radio-frequency power during an on-period of the first pulse unchanged and monotonously increase or decrease sequentially in steps a duty ratio of the first pulse as a plasma processing time elapses commencing from when the plasma processing is started and until when the plasma processing is finished. ### Claim 2 (depends on 1) The plasma processing apparatus according to claim 1, wherein the power control unit is configured to control the duty ratio based at least in part on an etching profile of the sample. ### Claim 3 (depends on 1) The plasma processing apparatus according to claim 1, wherein the power control unit is configured to control the first radio-frequency power supply to supply the first radio-frequency power during an active period of the first pulse to generate plasma. ### Claim 4 (depends on 1) The plasma processing apparatus according to claim 1, further comprising: a second pulse generator to generate a second pulse to modulate the second radio-frequency power, wherein the power control unit is configured to control the second pulse to have an active period corresponding to an active period of the first pulse. ### Claim 5 (depends on 4) The plasma processing apparatus according to claim 4, wherein the control unit monotonously decreases the duty ratio of the first pulse as the plasma processing time elapses, and monotonously increases the duty ratio of the second pulse as the plasma processing time elapses. ### Claim 6 (depends on 4) The plasma processing apparatus according to claim 4, wherein the control unit monotonously increases the duty ratio of the first pulse as the plasma processing time elapses, and monotonously decreases the duty ratio of the second pulse as the plasma processing time elapses. ### Claim 7 A plasma processing apparatus comprising: a plasma processing chamber to contain a sample to be processed; a first radio-frequency power supply to supply a first radio-frequency power to generate plasma; a second radio-frequency power supply to supply a second radio-frequency power to a sample stage configured to support the sample; a first pulse generator to generate a first pulse to time-modulate the first radio-frequency power; and a control unit configured to retain the first radio-frequency power during an on-period of the first pulse unchanged and monotonously change a duty ratio of the first pulse sequentially in steps from a first predetermined value to a second predetermined value as a plasma processing time elapses commencing from when the plasma processing is started and until when the plasma processing is finished. ### Claim 8 (depends on 7) The plasma processing apparatus according to claim 7, wherein the first predetermined value is smaller than the second predetermined value. ### Claim 9 (depends on 7) The plasma processing apparatus according to claim 7, wherein the first predetermined value is larger than the second predetermined value. ### Claim 10 (depends on 7) The plasma processing apparatus according to claim 7, further comprising: a second pulse generator to generate a second pulse to time-modulate the second radio-frequency power, wherein the control unit monotonously decreases the duty ratio of the first pulse as the plasma processing time elapses, and monotonously increases the duty ratio of the second pulse as the plasma processing time elapses. ### Claim 11 (depends on 7) The plasma processing apparatus according to claim 7, further comprising: a second pulse generator to generate a second pulse to time-modulate the second radio-frequency power, wherein the control unit monotonously increases the duty ratio of the first pulse as the plasma processing time elapses, and monotonously decreases the duty ratio of the second pulse as the plasma processing time elapses.