# US 11,121,649 B2 · Electrostatic workpiece-holding method and electrostatic workpiece-holding system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,121,649 B2 - Document ID: US11121649B2 - Status: Granted - Kind: B2 - Application number: 16/638,614 - Filed: 2018-07-25 - Published: 2020-06-04 - Granted: 2021-09-14 - Earliest claimed: 2017-08-28 - Assignees: Creative Technology Ltd - Applicants: Creative Technology Corporation - Inventors: Masaru Ozawa - Web page: https://patentgrep.com/patent/US11121649B2 ## CPC - H02N 13/00: Clutches or holding devices using electrostatic attraction, e.g. using Johnson-Rahbek effect - H10P 72/70: for supporting or gripping - H10P 72/722: {Details of electrostatic chucks} - H10P 72/7402: {Wafer tapes, e.g. grinding or dicing support tapes} - H01T 23/00: Apparatus for generating ions to be introduced into non-enclosed gases, e.g. into the atmosphere - H10P 72/0411: {for wet cleaning or washing} - H10P 72/3302: {Mechanical parts of transfer devices} - H02N: ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 - H01T: SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES (overvoltage protection circuits H02H) ## Abstract An electrostatic workpiece-holding method includes an initialization step, a static elimination step, a workpiece setting step, a workpiece attracting step, and a workpiece release step. The initialization step is a step of applying a positive voltage to electrode of the electrostatic attracting part while applying a negative voltage to electrode. The static elimination step is a step of removing the static charge on the surface of the electrostatic attracting part. The workpiece setting step is a step of placing the workpiece in contact with the surface of the electrostatic attracting part. The workpiece attracting step is a step of interrupting the application of the positive voltage to electrode of the electrostatic attracting part and the application of the negative voltage to electrode. The workpiece release step is a step of applying the positive voltage to electrode of the electrostatic attracting part while applying the negative voltage to electrode. ## Claims ### Claim 1 An electrostatic workpiece-holding method for holding a workpiece, by an electrostatic attraction force, on a surface of an electrostatic attracting part formed of one or more first electrodes capable of applying a positive voltage, one or more second electrodes capable of applying a negative voltage, and a dielectric covering these first and second electrodes, comprising: an initialization step of applying a positive voltage to the first electrode(s) and applying a negative voltage to the second electrode(s); a static elimination step of eliminating charges on the surface of the electrostatic attracting part after the execution of the initialization step; a workpiece setting step of abutting a workpiece against the surface of the electrostatic attracting part after the execution of the static elimination step; a workpiece attracting step of interrupting the application of the positive voltage to the first electrode(s) and the application of the negative voltage to the second electrode(s) after the execution of the workpiece setting step; and a workpiece release step of applying a positive voltage to the first electrode(s) and applying a negative voltage to the second electrode(s) after the execution of the workpiece attracting step. ### Claim 2 (depends on 1) The electrostatic workpiece-holding method according to claim 1, wherein the static elimination step eliminates the charges on the surface of the electrostatic attracting part by applying a very weak X-ray to a gas around the electrostatic attracting part and ionizing the gas. ### Claim 3 (depends on 1) The electrostatic workpiece-holding method according to claim 1, wherein the first and second electrodes of the electrostatic attracting part are either flat plate-shaped electrodes juxtaposed so as to adjoin each other at a predetermined interval or comb-shaped electrodes arranged so as to mesh with each other at a predetermined interval. ### Claim 4 An electrostatic workpiece-holding system comprising an electrostatic attracting part formed of one or more first electrodes capable of applying a positive voltage, one or more second electrodes capable of applying a negative voltage, and a dielectric covering these first and second electrodes, a power supply part capable of applying a positive voltage to the first electrode(s) and applying a negative voltage to the second voltage(s), a static eliminating part eliminating charges on a surface of the electrostatic attracting part, a workpiece setting part capable of abutting a workpiece against the surface of the electrostatic attracting part and taking out the workpiece from the surface of the electrostatic attracting part, and a control part controlling the workpiece setting part, the static eliminating part, and the power supply part, wherein the control part comprises an initializing part turning on the power supply part; a static elimination driving part driving the static eliminating part after the actuation of the initializing part; a workpiece abutting part driving the workpiece setting part to abut the workpiece against the surface of the electrostatic attracting part after the actuation of the static elimination driving part; a workpiece attracting part turning off the power supply part after the actuation of the workpiece abutting part; and a workpiece releasing part turning on the power supply part and driving the workpiece setting part to take out the workpiece from the electrostatic attracting part after the actuation of the workpiece attracting part. ### Claim 5 (depends on 4) The electrostatic workpiece-holding system according to claim 4, wherein the static eliminating part is a static eliminator for eliminating the charges on the surface of the electrostatic attracting part by applying a very weak X-ray to a gas around the electrostatic attracting part and ionizing the gas. ### Claim 6 (depends on 4) The electrostatic workpiece-holding system according to claim 4, wherein the first and second electrodes of the electrostatic attracting part are either flat plate-shaped electrodes juxtaposed so as to adjoin each other at a predetermined interval or comb-shaped electrodes arranged so as to mesh with each other at a predetermined interval. ### Claim 7 A workpiece-holding device, comprising: an electrostatic attracting part attracting a workpiece on a surface thereof, and including a first electrode, a second electrode, and a dielectric covering the first electrode and the second electrode, and a static eliminator for ionizing a gas around the electrostatic attracting part to thereby eliminate charges on the surface of the electrostatic attracting part, wherein the first electrode and the second electrode are flat plate-shaped electrodes juxtaposed so as to adjoin each other at a predetermined interval, the surface of the electrostatic attracting part above the first electrode is negatively charged and the surface of the electrostatic attracting part above the second electrode is positively charged with potentials of the first electrode and the second electrode maintained at 0 volts, and after the charges on the surface of the electrostatic attracting part is eliminated, a positive charge is charged on the workpiece above the first electrode and a negative charge is charged on the workpiece above the second electrode, whereby the workpiece is attracted to the electrostatic attracting part in an electrostatic induction state in which an inside of the workpiece has an electric field of zero. ### Claim 8 (depends on 7) The workpiece-holding device according to claim 7, wherein the workpiece is attracted to the electrostatic attracting part by a Coulomb force. ### Claim 9 (depends on 7) The workpiece-holding device according to claim 7, wherein the workpiece is a conductor or a semiconductor. ### Claim 10 A workpiece-holding device, comprising: an electrostatic attracting part attracting a workpiece to a surface of the electrostatic attracting part, and including a first electrode, a second electrode, and a dielectric covering the first electrode and the second electrode, and a static eliminator for ionizing a gas around the electrostatic attracting part to thereby eliminate charges on the surface of the electrostatic attracting part, wherein the first electrode and the second electrode are comb-shaped electrodes arranged so as to mesh with each other at a predetermined interval, the surface of the electrostatic attracting part above each tooth part of the first electrode is positively charged and the surface of the electrostatic attracting part above each tooth part of the second electrode is negatively charged with potentials of the first electrode and the second electrode maintained at 0 volts, and after the charges on the surface of the electrostatic attracting part is eliminated, a negative charge is charged on the workpiece above the each tooth part of the first electrode and a positive charge is charged on the workpiece above the each tooth part of the second electrode, whereby the workpiece is attracted to the electrostatic attracting part with an inside of the workpiece in a dielectric polarization state. ### Claim 11 (depends on 10) The workpiece-holding device according to claim 10, wherein the workpiece is attracted to the electrostatic attracting part by a gradient force. ### Claim 12 (depends on 10) The workpiece-holding device according to claim 10, wherein the workpiece is a conductor, a semiconductor, or an insulator. ### Claim 13 (depends on 7) The workpiece-holding device according to claim 7, wherein the dielectric is made of resin or ceramic. ### Claim 14 (depends on 7) The workpiece-holding device according to claim 7, wherein the static eliminator is disposed above the electrostatic attracting part, and applies an X-ray to the gas around the electrostatic attracting part to ionize the gas. ### Claim 15 (depends on 10) The workpiece-holding device according to claim 10, wherein the static eliminator is disposed above the electrostatic attracting part, and applies an X-ray to the gas around the electrostatic attracting part to ionize the gas.