Method for holding edge ring, plasma processing apparatus, and substrate processing system

Abstract

A first electrostatic chuck of a substrate support of a plasma processing apparatus of the present invention has first and second electrodes that hold a edge ring. A second electrostatic chuck of the substrate support holds a substrate. The first electrode extends closer to the second electrostatic chuck than the second electrode. In plasma processing, a first voltage having a positive polarity is applied to the first and second electrodes. During a first period after plasma processing, a second voltage having a negative polarity is applied to the first and second electrodes. During a second period after the first period, a third voltage having a positive polarity is applied to the first electrode and a fourth voltage having a negative polarity is applied to the second electrode. The absolute value of the third voltage is less than the absolute value of the first voltage and the absolute value of the second voltage.

Description

TECHNICAL FIELD

[0001] An exemplary embodiment of the present application relates to a method for holding a edge ring, a plasma processing apparatus, and a substrate processing system. BACKGROUND

[0002] A plasma processing of a substrate is performed using a plasma processing apparatus. The plasma processing apparatus has a chamber and a substrate support. The substrate support is configured to support an edge ring and a substrate. The substrate support includes an electrostatic chuck. The substrate is disposed on the electrostatic chuck and within an area surrounded by the edge ring.

[0003] The electrostatic chuck of the plasma processing apparatus described in Japanese Patent Application Publication No. 2016-122740 and Japanese Patent Application Publication No. 2018-206935 has two electrodes in order to hold the edge ring. The edge ring is held by the electrostatic chuck by applying a voltage of the same polarity or different polarities to the two electrodes. SUMMARY

[0004] The present application provides a technology related to holding of an edge ring for suppressing misalignment of a substrate on a substrate support.

[0005] In one exemplary embodiment, a method for holding an edge ring is provided. The holding method includes a step of applying a first voltage to a first electrode and a second electrode of a first electrostatic chuck in order to hold the edge ring by the first electrostatic chuck of a substrate support during a plasma processing of a substrate within a chamber of a plasma processing apparatus. The first voltage has a positive polarity. The plasma processing is performed in a state where the substrate is placed on a second electrostatic chuck of the substrate support within an area surrounded by the edge ring. The holding method further includes a step of applying a second voltage to the first electrode and the second electrode in order to hold the edge ring by the first electrostatic chuck during a first period after the plasma processing and after the substrate is carried out from the chamber. The second voltage has a negative polarity. Cleaning of the chamber is performed using a plasma generated within the chamber during the first period. The holding method includes a step of applying a third voltage and a fourth voltage to the first electrode and the second electrode, respectively, in order to hold the edge ring by the first electrostatic chuck during a second period after the first period. Cleaning of the chamber is performed using a plasma generated within the chamber during the second period. The first electrode extends closer to the second electrostatic chuck than the second electrode. The third voltage has a positive polarity and the fourth voltage has a negative polarity. An absolute value of the third voltage is smaller than an absolute value of the first voltage and an absolute value of the second voltage, and is equal to or smaller than an absolute value of the fourth voltage.

[0006] Furthermore, in another exemplary embodiment, a method for holding an edge ring is provided. The holding method includes a step of applying voltages of different polarities to a first electrode and a second electrode of a first electrostatic chuck of a substrate support disposed within a chamber of a plasma processing apparatus in order to hold the edge ring. The voltage application step is performed during the cleaning process of the chamber using plasma in the plasma processing apparatus. The substrate support has a second electrostatic chuck for holding a substrate placed thereon within a region surrounded by the edge ring. The first electrode extends closer to the second electrostatic chuck than the second electrode. In the voltage application step, a voltage of negative polarity is applied to the second electrode, and a voltage of positive polarity, having an absolute value smaller than the absolute value of the voltage applied to the second electrode, is applied to the first electrode. The holding method further includes a step of, after the voltage application step, transferring the substrate onto the second electrostatic chuck of the substrate support within the region surrounded by the edge ring.

[0007] According to the above exemplary embodiments, the edge ring can be maintained to suppress the amount of misalignment of the substrate on the substrate support. Attached Figure Description

[0008] Figure 1 This is a flowchart of an edge loop retention method according to an exemplary implementation.

[0009] Figure 2 This is a diagram illustrating a substrate processing system according to an exemplary embodiment.

[0010] Figure 3 This is a schematic diagram illustrating a plasma processing apparatus according to an exemplary embodiment.

[0011] Figure 4 This is a diagram illustrating the structure within the chamber of a plasma processing apparatus according to an exemplary embodiment.

[0012] Figure 5 Is with Figure 1 The timing diagram related to the method is shown.

[0013] Figure 6 (a) is a graph showing the center position of the sample substrate as determined in Experiment 1. Figure 6 (b) is a graph showing the center position of the sample substrate as determined in Experiment 2. Figure 6 (c) is a diagram showing the center position of the sample substrate as determined in Experiment 3.

[0014] Figure 7 (a) is a graph showing the center position of the sample substrate as determined in experiment 4. Figure 7 (b) is a graph showing the center position of the sample substrate as determined in experiment 5.Figure 7 (c) is a graph showing the center position of the sample substrate measured in the 6th experiment. DETAILED DESCRIPTION

[0015] Hereinafter, various exemplary embodiments will be described.

[0016] In one exemplary embodiment, a holding method of an edge ring is provided. The holding method includes a step of applying a first voltage to a first electrode and a second electrode of a first electrostatic chuck in order to hold the edge ring by the first electrostatic chuck during a plasma process on a substrate in a chamber of a plasma processing apparatus. The first voltage has a positive polarity. The plasma process is performed in a state where the substrate is placed on a second electrostatic chuck of the substrate support in an area surrounded by the edge ring. The holding method further includes a step of applying a second voltage to the first electrode and the second electrode in order to hold the edge ring by the first electrostatic chuck during a first period after the plasma process and after the substrate is carried out from the chamber. The second voltage has a negative polarity. Cleaning of the chamber is performed using plasma generated in the chamber during the first period. The holding method includes a step of applying a third voltage and a fourth voltage to the first electrode and the second electrode, respectively, in order to hold the edge ring by the first electrostatic chuck during a second period after the first period. Cleaning of the chamber is performed using plasma generated in the chamber during the second period. The first electrode extends closer to the second electrostatic chuck than the second electrode. The third voltage has a positive polarity, and the fourth voltage has a negative polarity. An absolute value of the third voltage is smaller than absolute values of the first voltage and the second voltage, and is equal to or smaller than an absolute value of the fourth voltage.

[0017] In the above-described embodiment, in order to suppress charge migration, the second voltage used during the first period has a polarity opposite to that of the first voltage used during the execution of the plasma process, i.e., a negative polarity. During the second period after the first period, the first electrode extending relatively close to the second electrostatic chuck is applied with the third voltage having a positive polarity and a relatively low value, and the second electrode is applied with the fourth voltage having a negative polarity. As a result, misalignment of another substrate carried onto the second electrostatic chuck after the cleaning is performed can be suppressed.

[0018] In one exemplary embodiment, an absolute value of the third voltage can be smaller than an absolute value of the fourth voltage.

[0019] In one exemplary embodiment, an absolute value of the fourth voltage can be equal to absolute values of the first voltage and the second voltage.

[0020] In one exemplary embodiment, an absolute value of the second voltage can be equal to an absolute value of the first voltage. In the case where the absolute value of the second voltage is equal to the absolute value of the first voltage, charge migration can be more effectively suppressed.

[0021] In one example embodiment, the plasma generated in the first period can be a plasma generated from oxygen gas. The plasma generated in the second period can be a plasma generated from nitrogen gas.

[0022] In one example embodiment, the holding method further includes, after the process of applying the third voltage and the fourth voltage, a process of carrying another substrate to the second electrostatic chuck by the carrying device. In a state where the another substrate is placed on the second electrostatic chuck and the edge ring is held by the first electrostatic chuck by applying the first voltage to the first electrode and the second electrode, the another substrate can be further subjected to the plasma treatment.

[0023] In another example embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, a power supply apparatus, and a control section. The substrate support is configured to support a substrate in the chamber. The substrate support includes a first electrostatic chuck and a second electrostatic chuck. The first electrostatic chuck is configured to hold an edge ring placed thereon. The second electrostatic chuck is configured to hold a substrate placed thereon. The first electrostatic chuck includes a first electrode and a second electrode. The first electrode extends closer to the second electrostatic chuck than the second electrode. The power supply apparatus includes one or more direct current power supplies. The power supply apparatus is configured to generate voltages applied to the first electrode and the second electrode. The control section controls the power supply apparatus to apply a first voltage having a positive polarity to the first electrode and the second electrode in order to hold the edge ring by the first electrostatic chuck during a plasma treatment of the substrate placed on the second electrostatic chuck. The control section controls the power supply apparatus to apply a second voltage having a negative polarity to the first electrode and the second electrode in a first period after the plasma treatment and after the substrate is carried out of the chamber. In the first period, cleaning of the chamber is performed using a plasma generated in the chamber. The control section controls the power supply apparatus to apply a third voltage to the first electrode and a fourth voltage to the second electrode in order to hold the edge ring by the first electrostatic chuck in a second period. The second period is a period after the first period. In the second period, cleaning of the chamber is performed using a plasma generated in the chamber. The third voltage has a positive polarity, and the fourth voltage has a negative polarity. An absolute value of the third voltage is smaller than absolute values of the first voltage and the second voltage and is equal to or smaller than an absolute value of the fourth voltage.

[0024] In one example embodiment, the absolute value of the third voltage can be smaller than the absolute value of the fourth voltage.

[0025] In one example embodiment, the absolute value of the fourth voltage can be equal to the absolute values of the first voltage and the second voltage.

[0026] In one example embodiment, the absolute value of the second voltage can be equal to the absolute value of the first voltage.

[0027] In still another example embodiment, a substrate processing system is provided. The substrate processing system has the plasma processing apparatus and the carrier device of any of the above example embodiments. The control section controls the carrier device to carry another substrate onto the second electrostatic chuck after the cleaning in the second period is performed. The control section controls the power supply device to apply the first voltage to the first and second electrodes in order to hold the edge ring by the electrostatic chuck during the plasma processing of the another substrate placed on the second electrostatic chuck.

[0028] In still another example embodiment, a holding method of an edge ring is provided. The holding method includes a step of applying voltages having different polarities to a first electrode and a second electrode of a first electrostatic chuck provided in a chamber of a plasma processing apparatus in order to hold an edge ring by the first electrostatic chuck. The step of applying the voltages is performed during cleaning of a chamber in which plasma is used in the plasma processing apparatus. The substrate support has a second electrostatic chuck for holding a substrate placed thereon in an area surrounded by the edge ring. The first electrode extends closer to the second electrostatic chuck than the second electrode. In the step of applying the voltages, a voltage having a negative polarity is applied to the second electrode and a voltage having an absolute value smaller than that of the voltage applied to the second electrode and having a positive polarity is applied to the first electrode. The holding method further includes a step of carrying a substrate into the area surrounded by the edge ring and onto the second electrostatic chuck of the substrate support after the step of applying the voltages.

[0029] Hereinafter, various example embodiments will be described in detail with reference to the accompanying drawings. In addition, the same or like parts are designated by the same reference numerals throughout the various drawings.

[0030] Figure 1 is a flowchart of a holding method of an edge ring according to an example embodiment. Figure 1 The holding method shown (hereinafter, referred to as "method MT") can be applied to a substrate processing system or a plasma processing apparatus.

[0031] Figure 2 is a diagram showing a substrate processing system according to an example embodiment. Figure 2 The substrate processing system PS shown has stages 2a to 2d, containers 4a to 4d, a load module LM, an aligner AN, load lock modules LL1, LL2, processing modules PM1 to PM6, a carrier device TF, and a control section MC. In addition, the number of stages, the number of containers, and the number of load lock modules in the substrate processing system PS can be any number of one or more. Also, the number of processing modules in the substrate processing system PS can be any number of one or more.

[0032] The stages 2a to 2d are arranged along one edge of the load module LM. The containers 4a to 4d are respectively mounted on the stages 2a to 2d. The containers 4a to 4d are respectively containers called FOUP (Front Opening Unified Pod), for example. The containers 4a to 4d are respectively configured to accommodate substrates W inside thereof.

[0033] The load module LM has a chamber. The pressure inside the chamber of the load module LM is set to be atmospheric pressure. The load module LM has a transfer device TU1. The transfer device TU1 is a multi-joint robot, for example, and is controlled by the control section MC. The transfer device TU1 is configured to transfer the substrates W via the chamber of the load module LM. The transfer device TU1 is capable of transferring the substrates W between each of the containers 4a to 4d and the aligner AN, between the aligner AN and each of the load lock modules LL1, LL2, and between each of the load lock modules LL1, LL2 and each of the containers 4a to 4d. The aligner AN is connected to the load module LM. The aligner AN is configured to perform adjustment of the position of the substrates W (calibration of the position).

[0034] The load lock module LL1 and the load lock module LL2 are respectively provided between the load module LM and the transfer module TF. The load lock module LL1 and the load lock module LL2 respectively provide a pre-decompression chamber.

[0035] The transfer module TF is connected to the load lock module LL1 and the load lock module LL2 via gate valves, respectively. The transfer module TF has a transfer chamber TC capable of being decompressed. The transfer module TF has a transfer device TU2. The transfer device TU2 is a multi-joint robot, for example, and is controlled by the control section MC. The transfer device TU2 is configured to transfer the substrates W via the transfer chamber TC. The transfer device TU2 is capable of transferring the substrates W between each of the load lock modules LL1, LL2 and each of the processing modules PM1 to PM6 and between any two of the processing modules PM1 to PM6.

[0036] The processing modules PM1 to PM6 are respectively devices configured to perform dedicated substrate processing. At least one of the processing modules PM1 to PM6 is a plasma processing device according to an exemplary embodiment described later.

[0037] The control section MC is configured to control each section of the substrate processing system PS. The control section MC can be a computer provided with a processor, a storage device, an input device, a display device, and the like. The control section MC executes a control program stored in the storage device and controls each section of the substrate processing system PS according to process data stored in the storage device. The method MT can be executed in the substrate processing system PS by the control of each section of the substrate processing system PS by the control section MC.

[0038] Figure 3 is a view schematically showing a plasma processing apparatus according to an example embodiment. Figure 3 The plasma processing apparatus 1 shown can be employed as at least one of the processing modules PM1 to PM6 of the substrate processing system PS. The plasma processing apparatus 1 is provided with a chamber 10. Figure 4 is a view showing a structure in the chamber of a plasma processing apparatus according to an example embodiment. As shown in Figure 4 The plasma processing apparatus 1 shown can be employed as at least one of the processing modules PM1 to PM6 of the substrate processing system PS. The plasma processing apparatus 1 is provided with a chamber 10.

[0039] An internal space 10s is provided in the chamber 10. A central axis of the internal space 10s is an axis AX extending in the vertical direction. In an embodiment, the chamber 10 includes a chamber body 12. The chamber body 12 has a substantially cylindrical shape. The internal space 10s is provided in the chamber body 12. The chamber body 12 is formed of, for example, aluminum. The chamber body 12 is electrically grounded. A film having plasma resistance is formed on an inner wall surface of the chamber body 12, that is, a wall surface that divides the internal space 10s. The film can be a film formed by an anodizing treatment or a ceramic film such as a film formed of yttrium oxide.

[0040] A passage 12p is formed in a side wall of the chamber body 12. The passage 12p is passed through when the substrate W is carried between the internal space 10s and the outside of the chamber 10. A gate valve 12g is provided along the side wall of the chamber body 12 for opening and closing of the passage 12p.

[0041] The plasma processing apparatus 1 is further provided with a substrate support 16. The substrate support 16 is configured to support a substrate W placed thereon in the chamber 10. The substrate W has a substantially disc shape. The substrate support 16 is supported by a support portion 17. The support portion 17 extends upward from a bottom portion of the chamber body 12. The support portion 17 has a substantially cylindrical shape. The support portion 17 is formed of an insulating material such as quartz.

[0042] The substrate support 16 has a lower electrode 18, an electrostatic chuck 21, and an electrostatic chuck 22. The lower electrode 18, the electrostatic chuck 21, and the electrostatic chuck 22 are provided in the chamber 10.

[0043] The lower electrode 18 is formed of an electrically conductive material such as aluminum and has a substantially disc shape. The lower electrode 18 has a flow path 18f provided therein. The flow path 18f is a flow path for a heat exchange medium. As the heat exchange medium, for example, a refrigerant in a liquid state is used. A supply device (for example, a cooling unit) for the heat exchange medium is connected to the flow path 18f. The supply device is provided outside the chamber 10. The heat exchange medium is supplied from the supply device to the flow path 18f via a pipe 23a. The heat exchange medium supplied to the flow path 18f is returned to the supply device via a pipe 23b.

[0044] The electrostatic chuck 21 and the electrostatic chuck 22 are provided on the lower electrode 18. The electrostatic chuck 21 is a second electrostatic chuck of the embodiment. The electrostatic chuck 21 is configured to hold a substrate W placed thereon. The substrate W can have a substantially disc shape. The electrostatic chuck 22 is a first electrostatic chuck of the embodiment. The electrostatic chuck 22 is configured to hold an edge ring ER placed thereon. The edge ring ER is a plate having a substantially ring shape. The edge ring ER is formed of, for example, silicon, silicon carbide, or quartz. The edge ring ER is placed on the electrostatic chuck 22 in a manner that a central axis thereof coincides with the axis AX. The substrate W housed in the chamber 10 is disposed on the electrostatic chuck 21 in an area surrounded by the edge ring ER.

[0045] The plasma processing apparatus 1 can further be provided with a gas line 25. The gas line 25 supplies a heat transfer gas, such as He gas, from a gas supply mechanism to a gap between an upper surface of the electrostatic chuck 21 and a back surface (lower surface) of the substrate W.

[0046] The plasma processing apparatus 1 can further be provided with a peripheral portion 28 and a peripheral portion 29. The peripheral portion 28 extends upward from a bottom of the chamber body 12. The peripheral portion 28 has a substantially cylindrical shape and extends along an outer periphery of the support portion 17. The peripheral portion 28 is formed of an electrically conductive material. The peripheral portion 28 is electrically grounded. A film having plasma resistance is formed on a surface of the peripheral portion 28. The film can be a film formed by an anodization treatment or a ceramic film such as a film formed of yttrium oxide.

[0047] The peripheral portion 29 is provided on the peripheral portion 28. The peripheral portion 29 is formed of a material having insulation. The peripheral portion 29 is formed of, for example, a ceramic such as quartz. The peripheral portion 29 has a substantially cylindrical shape. The peripheral portion 29 extends along an outer periphery of the lower electrode 18 and the electrostatic chuck 22.

[0048] The plasma processing apparatus 1 is further provided with an upper electrode 30. The upper electrode 30 is provided above the substrate support 16. The upper electrode 30 closes an upper opening of the chamber body 12 together with a member 32. The member 32 has insulation. The upper electrode 30 is supported to an upper portion of the chamber body 12 via the member 32.

[0049] The upper electrode 30 includes a top plate 34 and a support body 36. A lower surface of the top plate 34 divides the internal space 10s. A plurality of exhaust holes 34a are formed on the top plate 34. The plurality of exhaust holes 34a respectively penetrate the top plate 34 in a plate thickness direction (vertical direction). The top plate 34 is formed of, for example, silicon. Alternatively, the top plate 34 can have a structure in which a film having plasma resistance is provided on a surface of an aluminum member. The film can be a film formed by an anodization treatment or a ceramic film such as a film formed of yttrium oxide.

[0050] The support body 36 supports the top plate 34 removably. The support body 36 is formed of, for example, an electrically conductive material such as aluminum. A gas diffusion chamber 36a is provided in the inside of the support body 36. A plurality of gas holes 36b extend downward from the gas diffusion chamber 36a. The plurality of gas holes 36b respectively communicate with the plurality of exhaust holes 34a. A gas introduction port 36c is formed in the support body 36. The gas introduction port 36c is connected to the gas diffusion chamber 36a. A gas supply pipe 38 is connected to the gas introduction port 36c.

[0051] The gas supply pipe 38 is connected to a gas source group 40 via a valve group 41, a flow rate controller group 42, and a valve group 43. The gas supply part is constituted by the gas source group 40, the valve group 41, the flow rate controller group 42, and the valve group 43. The gas source group 40 includes a plurality of gas sources. The valve group 41 and the valve group 43 each include a plurality of valves (for example, on-off valves). The flow rate controller group 42 includes a plurality of flow rate controllers. The plurality of flow rate controllers of the flow rate controller group 42 are each a mass flow controller or a pressure control type flow rate controller. The plurality of gas sources of the gas source group 40 are each connected to the gas supply pipe 38 via a valve corresponding to the valve group 41, a flow rate controller corresponding to the flow rate controller group 42, and a valve corresponding to the valve group 43. The plasma processing apparatus 1 is capable of supplying gas from one or more gas sources selected from the plurality of gas sources of the gas source group 40 to the internal space 10s at respectively adjusted flow rates.

[0052] A baffle 48 is provided between the outer peripheral portion 28 and the side wall of the chamber body 12. The baffle 48 can be constituted, for example, by coating a ceramic such as yttria on an aluminum member. A plurality of through holes are formed in the baffle 48. An exhaust pipe 52 is connected to the bottom of the chamber body 12 below the baffle 48. An exhaust device 50 is connected to the exhaust pipe 52. The exhaust device 50 has a pressure controller such as an automatic pressure control valve and a vacuum pump such as a turbo molecular pump, and is capable of reducing the pressure in the internal space 10s.

[0053] The plasma processing apparatus 1 further has a high-frequency power supply 61. The high-frequency power supply 61 is connected to the upper electrode 30 via a matcher 63. The high-frequency power supply 61 is a power supply that generates high-frequency electric power for generating plasma. The high-frequency electric power generated by the high-frequency power supply 61 has a first frequency in a range of 27 MHz or more and 100 MHz or less. The first frequency is, for example, 40 MHz or 60 MHz. The matcher 63 has a matching circuit for matching the impedance of the load side (the lower electrode 18 side) of the high-frequency power supply 61 to the output impedance of the high-frequency power supply 61. In addition, the high-frequency power supply 61 can not be electrically connected to the upper electrode 30, but can be connected to the lower electrode 18 via the matcher 63.

[0054] The plasma processing apparatus 1 can further be provided with a bias power supply 62. The bias power supply 62 is electrically connected to the lower electrode 18 via a matcher 64. The bias power supply 62 generates an electric bias. The electric bias is applied to the lower electrode 18. In one embodiment, the electric bias can be a high-frequency bias power. The high-frequency bias power has a second frequency. The second frequency can be a frequency lower than the first frequency. The second frequency is, for example, a frequency in a range of 50 kHz or more and 27 MHz or less. In this embodiment, the bias power supply 62 is connected to the lower electrode 18 via the matcher 64. The matcher 64 has a matching circuit configured to match an impedance of a load side (the lower electrode 18 side) of the bias power supply 62 to an output impedance of the bias power supply 62.

[0055] In another embodiment, the electric bias can be a pulse wave that is generated periodically with a period defined by the second frequency and that includes a pulse of a negative direct-current voltage. In this embodiment, the matcher 64 can be omitted. The second frequency is, for example, a frequency in a range of 50 kHz or more and 27 MHz or less. The voltage level of the pulse wave can also be 0 V during a period other than the period during which the pulse of the negative direct-current voltage lasts. Alternatively, the voltage of the pulse wave can have an absolute value lower than the absolute value of the voltage of the pulse during a period other than the period during which the pulse of the negative direct-current voltage lasts. In addition, the voltage level of the pulse can vary with time.

[0056] In the plasma processing apparatus 1, a high-frequency electric field is generated in the chamber 10 by the high-frequency power from the high-frequency power supply 61. A gas in the chamber 10 is excited by the generated high-frequency electric field. As a result, a plasma is generated in the chamber 10. The substrate W is processed by chemical species such as ions and / or radicals from the generated plasma.

[0057] Hereinafter, the electrostatic chuck 21 and the electrostatic chuck 22 of the substrate support 16 will be described in detail. The electrostatic chuck 21 extends in a manner crossing the axis AX. The electrostatic chuck 22 extends in a circumferential direction on a radially outer side with respect to the electrostatic chuck 21.

[0058] The electrostatic chuck 21 is configured to hold the substrate W placed thereon (i.e., on the upper surface thereof). The electrostatic chuck 21 has a dielectric portion 21d and an electrode 21a. The dielectric portion 21d is formed of a dielectric such as aluminum nitride or aluminum oxide. The dielectric portion 21d has a substantially disc shape. The central axis of the electrostatic chuck 21 and the dielectric portion 21d substantially coincides with the axis AX. The electrode 21a is a film-like electrode provided in the dielectric portion 21d. The direct-current power supply 55 is connected to the electrode 21a via a switch 56. When a direct-current voltage from the direct-current power supply 55 is applied to the electrode 21a, electrostatic attraction is generated between the electrostatic chuck 21 and the substrate W. By the generated electrostatic attraction, the substrate W is attracted to the electrostatic chuck 21 and held thereby.

[0059] The electrostatic chuck 22 is configured to hold the edge ring ER placed thereon. The electrostatic chuck 22 has a dielectric portion 22d, a first electrode 22a, and a second electrode 22b. The dielectric portion 22d is formed of a dielectric such as aluminum nitride or aluminum oxide. The dielectric portion 22d extends in the circumferential direction on the radially outer side of the dielectric portion 21d. The central axis of the dielectric portion 22d substantially coincides with the axis AX. In one embodiment, the thickness of the dielectric portion 22d is smaller than the thickness of the dielectric portion 21d. The position of the upper surface of the dielectric portion 22d in the vertical direction can be lower than the position of the upper surface of the dielectric portion 21d in the vertical direction.

[0060] In one embodiment, as shown in FIG. 2, the dielectric portion 21d and the dielectric portion 22d can be configured from a single dielectric member. That is, the electrostatic chuck 21 and the electrostatic chuck 22 can also be integrated. In this case, the boundary between the dielectric portion 21d of the electrostatic chuck 21 and the dielectric portion 22d of the electrostatic chuck 22 is indicated by a broken line. Alternatively, the electrostatic chuck 21 and the electrostatic chuck 22 can also be separated from each other. Figure 3 Figure 3 In one embodiment, as shown in FIG. 2, the dielectric portion 21d and the dielectric portion 22d can be configured from a single dielectric member. That is, the electrostatic chuck 21 and the electrostatic chuck 22 can also be integrated. In this case, the boundary between the dielectric portion 21d of the electrostatic chuck 21 and the dielectric portion 22d of the electrostatic chuck 22 is indicated by a broken line. Alternatively, the electrostatic chuck 21 and the electrostatic chuck 22 can also be separated from each other.

[0061] The first electrode 22a and the second electrode 22b are each a film-shaped electrode. The first electrode 22a and the second electrode 22b are provided in the dielectric portion 22d. The first electrode 22a extends closer to the electrostatic chuck 21 than the second electrode 22b. In one embodiment, the first electrode 22a and the second electrode 22b can each extend around the axis AX. Also, each of the first electrode 22a and the second electrode 22b can have a ring shape. In this case, the second electrode 22b extends in the circumferential direction on the outer side of the first electrode 22a. The first electrode 22a and the second electrode 22b can each extend at substantially the same height position in the vertical direction.

[0062] The plasma processing apparatus 1 further has a power supply device 70. The power supply device 70 is connected to the first electrode 22a and the second electrode 22b. The power supply device 70 is configured to generate a voltage to be applied to the first electrode 22a and a voltage to be applied to the second electrode 22b. The voltage to be applied to the first electrode 22a and the voltage to be applied to the second electrode 22b are each a direct current voltage. The power supply device 70 has one or more direct current power supplies. In one embodiment, the power supply device 70 can have a variable direct current power supply 71, a variable direct current power supply 72, a switch 73, and a switch 74. The variable direct current power supply 71 is configured to generate a direct current voltage to be applied to the first electrode 22a. The variable direct current power supply 71 is connected to the first electrode 22a via the switch 73. The variable direct current power supply 72 is configured to generate a direct current voltage to be applied to the second electrode 22b. The variable direct current power supply 72 is connected to the second electrode 22b via the switch 74.

[0063] ​When the voltage from the power supply device 70 is applied to the first electrode 22a and the second electrode 22b, respectively, electrostatic attraction is generated between the electrostatic chuck 22 and the edge ring ER. By the generated electrostatic attraction, the edge ring ER is attracted to and held by the electrostatic chuck 22.

[0064] The electrostatic chuck 22 can also have a gas line 22g. The gas line 22g is a gas line provided to supply a heat transfer gas, such as He gas, to the gap between the electrostatic chuck 22 and the edge ring ER. The gas line 22g is connected to the gas supply mechanism 86 as a heat transfer gas source.

[0065] In one embodiment, the control section MC of the substrate processing system PS can also constitute the control section MC of the plasma processing apparatus 1. In this embodiment, the control section MC can control each section of the plasma processing apparatus 1. Alternatively, the plasma processing apparatus 1 can not have the control section MC, but have another control section configured to control each section thereof. The other control section, like the control section MC, can be a computer.

[0066] Referring again to Figure 1 , the method MT will be described. Hereinafter, the control based on the control section MC will be described along with the method MT. In the following description, the method MT will be described along with Figure 1 . Figure 5 . Figure 5 is a timing chart related to the method shown in Figure 1 . In Figure 5 , the horizontal axis represents time. In Figure 5 , the vertical axis represents the applied voltage to the first electrode 22a, the applied voltage to the second electrode 22b, and the supply state of the heat transfer gas from the gas supply mechanism 86. "ON" of the supply state of the heat transfer gas indicates that the heat transfer gas is supplied to the gap between the electrostatic chuck 22 and the edge ring ER. "OFF" of the supply state of the heat transfer gas indicates that the heat transfer gas is not supplied to the gap between the electrostatic chuck 22 and the edge ring ER.

[0067] In the process ST1 of the method MT, the substrate W is carried onto the electrostatic chuck 22. In the process ST1, the control section MC controls the carrying device TU2 to carry the substrate W onto the electrostatic chuck 22. During the execution of the process ST1, the edge ring ER is held by the electrostatic chuck 22. As Figure 5As shown, during the execution of process ST1, the voltage applied to the first electrode 22a is voltage VA, and the voltage applied to the second electrode 22b is voltage VB. Voltage VA can be a positive voltage, and voltage VB can be a negative voltage. The absolute values ​​of voltage VA and voltage VB can be the same. During the execution of process ST1, the control unit MC controls the power supply device 70 to apply voltage VA and voltage VB to the first electrode 22a and the second electrode 22b, respectively. During the execution of process ST1, heat transfer gas from the gas supply mechanism 86 is not supplied to the gap between the electrostatic chuck 22 and the edge ring ER. During the execution of process ST1, the control unit MC controls the gas supply mechanism 86 to stop the supply of heat transfer gas.

[0068] The subsequent process ST2 is performed to hold the edge ring ER by the electrostatic chuck 22 during plasma treatment of the substrate W. During plasma treatment, a processing gas is supplied into the chamber 10 from the gas supply unit. The pressure of the processing gas in the chamber 10 is set to a specified pressure by the exhaust device 50 during plasma treatment. Furthermore, high-frequency power is supplied from the high-frequency power supply 61 during plasma treatment. As a result, plasma is generated within the chamber 10 by the processing gas. During plasma treatment, an electrical bias can also be supplied to the lower electrode 18 from the bias power supply 62. During plasma treatment, the gas supply unit, exhaust device 50, high-frequency power supply 61, and bias power supply 62 are controlled by the control unit MC. During plasma treatment, the substrate W is treated with chemical species from the plasma. That is, plasma treatment of the substrate W is performed. This plasma treatment can be, for example, plasma etching of a film on the substrate W.

[0069] In process ST2, in order for the edge ring ER to be held by the electrostatic chuck 22, a first voltage V1 with positive polarity is applied to the first electrode 22a and the second electrode 22b. For example... Figure 5 As shown, the absolute value of the first voltage V1 can be greater than the absolute values ​​of voltage VA and voltage VB. During the execution of process ST2, the control unit MC controls the power supply device 70 to apply the first voltage V1 to the first electrode 22a and the second electrode 22b. During the execution of process ST2, heat transfer gas from the gas supply mechanism 86 is supplied to the gap between the electrostatic chuck 22 and the edge ring ER. During the execution of process ST2, the control unit MC controls the gas supply mechanism 86 to supply heat transfer gas to the gap between the electrostatic chuck 22 and the edge ring ER. Furthermore, in process ST2, by generating a potential difference between the first electrode 22a and the second electrode 22b, DC voltages with different values ​​can be applied to the first electrode 22a and the second electrode 22b respectively.

[0070] In a subsequent process ST3, the substrate W is carried out of the chamber 10. In the process ST3, the control section MC controls the carrying device TU2 to carry the substrate W from the chamber 10. During the execution of the process ST3, the edge ring ER is held by the electrostatic chuck 22. As shown in FIG. 6, during the execution of the process ST3, the voltage VA is applied to the first electrode 22a and the voltage VB is applied to the second electrode 22b. During the execution of the process ST3, the control section MC controls the power supply device 70 to apply the voltage VA and the voltage VB to the first electrode 22a and the second electrode 22b, respectively. During the execution of the process ST3, the heat transfer gas from the gas supply mechanism 86 is not supplied to the gap between the electrostatic chuck 22 and the edge ring ER. During the execution of the process ST3, the control section MC controls the gas supply mechanism 86 to stop the supply of the heat transfer gas. Figure 5

[0071] A subsequent process ST4 is executed in a first period after the above-described plasma processing and after the substrate W is carried out of the chamber 10 in the process ST3. In the first period, cleaning of the chamber 10 is executed using the plasma generated in the chamber 10 (hereinafter, referred to as "first cleaning"). The first cleaning is executed in a state where no object is placed on the electrostatic chuck 21. Alternatively, cleaning of the chamber 10 can be executed using the plasma generated in the chamber 10 in a state where a dummy substrate is placed on the electrostatic chuck 21 between the process ST3 and the process ST4.

[0072] During the execution of the first cleaning, a cleaning gas is supplied from the gas supply section into the chamber 10. In one embodiment, the cleaning gas can contain oxygen. During the execution of the first cleaning, the pressure of the cleaning gas in the chamber 10 is set to a specified pressure by the exhaust device 50. Also, during the execution of the first cleaning, high-frequency electric power is supplied from the high-frequency power source 61. As a result, a plasma is generated in the chamber 10 from the cleaning gas. During the execution of the first cleaning, an electric bias can be supplied to the lower electrode 18 from the bias power source 62 or no electric bias can be supplied. During the execution of the first cleaning, the gas supply section, the exhaust device 50, the high-frequency power source 61, and the bias power source 62 are controlled by the control section MC. During the execution of the first cleaning, deposits in the chamber 10 are removed by chemical species from the plasma. The deposits are generated in the above-described plasma processing of the substrate.

[0073] In the process ST4, the second voltage V2 having a negative polarity is applied to the first electrode 22a and the second electrode 22b in order to hold the edge ring ER by the electrostatic chuck 22. In one example, in order to control the charge migration, the second voltage V2 used in the process ST4 has a polarity opposite to that of the first voltage VI used during the execution of the plasma processing in the process ST2. As shown in FIG. 6, during the execution of the process ST4, the voltage VA is applied to the first electrode 22a and the voltage VB is applied to the second electrode 22b. During the execution of the process ST4, the control section MC controls the power supply device 70 to apply the voltage VA and the voltage VB to the first electrode 22a and the second electrode 22b, respectively. Figure 5 ​As shown, the absolute value of the second voltage V2 can be greater than the absolute value of the voltage VA and the absolute value of the voltage VB. The absolute value of the second voltage V2 can be the same as the absolute value of the first voltage VI. In this case, charge migration can be more effectively suppressed. Alternatively, the absolute value of the second voltage V2 can be less than the absolute value of the first voltage VI. During execution of the process ST4, the control section MC controls the power supply device 70 to apply the second voltage V2 to the first electrode 22a and the second electrode 22b. During execution of the process ST4, the heat transfer gas from the gas supply mechanism 86 is supplied to the gap between the electrostatic chuck 22 and the edge ring ER. During execution of the process ST4, the control section MC controls the gas supply mechanism 86 to supply the heat transfer gas to the gap between the electrostatic chuck 22 and the edge ring ER. In addition, in the process ST4, a direct current voltage having a positive polarity or a negative polarity and having the same value can be applied to the first electrode 22a and the second electrode 22b. Alternatively, in the process ST4, a direct current voltage having different values can be applied to the first electrode 22a and the second electrode 22b in a manner that a potential difference is generated between the first electrode 22a and the second electrode 22b.

[0074] A subsequent process ST5 is executed in a second period after the first period. In the second period, cleaning of the chamber 10 (hereinafter, referred to as "second cleaning") is executed using a plasma generated in the chamber 10. The second cleaning is executed in a state where the object is not placed on the electrostatic chuck 21.

[0075] During execution of the second cleaning, a cleaning gas is supplied from the gas supply section into the chamber 10. In an embodiment, the cleaning gas can contain nitrogen. During execution of the second cleaning, the pressure of the cleaning gas in the chamber 10 is set to a specified pressure by the exhaust device 50. Also, during execution of the second cleaning, high-frequency electric power is supplied from the high-frequency power source 61. As a result, a plasma is generated in the chamber 10 from the cleaning gas. During execution of the second cleaning, an electric bias can be supplied from the bias power source 62 to the lower electrode 18, or the electric bias can not be supplied. During execution of the second cleaning, the gas supply section, the exhaust device 50, the high-frequency power source 61, and the bias power source 62 are controlled by the control section MC. During execution of the second cleaning, deposits in the chamber 10 are removed by chemical species from the plasma.

[0076] In the process ST5, in order to hold the edge ring ER by the electrostatic chuck 22, a third voltage V3 is applied to the first electrode 22a, and a fourth voltage V4 is applied to the second electrode 22b. As shown in FIG. 6, the absolute value of the third voltage V3 can be greater than the absolute value of the voltage VA and the absolute value of the voltage VB. The absolute value of the third voltage V3 can be the same as the absolute value of the first voltage VI. In this case, charge migration can be more effectively suppressed. Alternatively, the absolute value of the third voltage V3 can be less than the absolute value of the first voltage VI. The fourth voltage V4 can have the same value as the third voltage V3. Alternatively, the fourth voltage V4 can have a different value from the third voltage V3. Figure 5As shown, the third voltage V3 has a positive polarity, and the fourth voltage V4 has a negative polarity. The absolute value of the third voltage V3 is less than the absolute values ​​of the first voltage V1 and the second voltage V2, and is less than the absolute value of the fourth voltage V4. The absolute value of the third voltage V3 may be less than the absolute value of the fourth voltage V4. The absolute value of the fourth voltage V4 may be equal to the absolute values ​​of the first voltage V1 and the second voltage V2. During the execution of process ST5, the control unit MC controls the power supply device 70 to apply the third voltage V3 to the first electrode 22a and the fourth voltage V4 to the second electrode 22b. During the execution of process ST5, heat transfer gas from the gas supply mechanism 86 is supplied to the gap between the electrostatic chuck 22 and the edge ring ER. During the execution of process ST5, the control unit MC controls the gas supply mechanism 86 to supply heat transfer gas to the gap between the electrostatic chuck 22 and the edge ring ER. The duration of the execution of process ST5 may be 10 seconds or more.

[0077] In the subsequent STJ process, it is determined whether the termination condition is met. The termination condition is met if there is no other substrate that should be subjected to plasma treatment. If the termination condition is not met in the STJ process, process ST6 is executed.

[0078] In process ST6, another substrate is transferred onto the electrostatic chuck 21. In process ST6, the control unit MC controls the transfer device TU2 to transfer the other substrate onto the electrostatic chuck 21. During the execution of process ST6, the edge ring ER is held by the electrostatic chuck 22. Figure 5 As shown, during the execution of process ST6, the voltage applied to the first electrode 22a is voltage VA, and the voltage applied to the second electrode 22b is voltage VB. During the execution of process ST6, the control unit MC controls the power supply device 70 to apply voltages VA and VB to the first electrode 22a and the second electrode 22b, respectively. During the execution of process ST6, heat transfer gas from the gas supply mechanism 86 is not supplied to the gap between the electrostatic chuck 22 and the edge ring ER. During the execution of process ST6, the control unit MC controls the gas supply mechanism 86 to stop the supply of heat transfer gas. After process ST6, the processing starting from process ST2 is executed again. That is, the plasma treatment of process ST2 is performed on another substrate. Then, processes ST3 to ST5 are executed. If the termination condition is met in the subsequent process STJ of process ST5, the method MT ends.

[0079] In the process ST5 of the method MT, the third voltage V3 having a positive polarity and having a relatively low value is applied to the first electrode 22a extending relatively close to the electrostatic chuck 21, and the fourth voltage V4 having a negative polarity is applied to the second electrode 22b. As a result, according to the method MT, misalignment of another substrate carried onto the electrostatic chuck 21 after the cleaning is performed can be suppressed.

[0080] The first to sixth experiments performed for evaluation of the method MT will be described below. In each of the first to sixth experiments, the plasma processing apparatus 1 was used. In each of the first to sixth experiments, the first to sixth processes were repeatedly performed. The first process is the same process as the process ST1, and in the first process, the sample substrate was carried onto the electrostatic chuck 21 using the carrying device TU2. During the performance of the first process, a direct current voltage of 2500 V was applied to the first electrode 22a, and a direct current voltage of -2500 V was applied to the second electrode 22b. The second process is the same process as the process ST2, and during the performance of the second process, a direct current voltage of 4000 V was applied to the first electrode 22a and the second electrode 22b. During the performance of the second process, plasma processing of the sample substrate was performed in the chamber 10. The third process is the same process as the process ST3, and the sample substrate was carried out of the chamber 10 using the carrying device TU2. During the performance of the third process, a direct current voltage of 2500 V was applied to the first electrode 22a, and a direct current voltage of -2500 V was applied to the second electrode 22b. In the subsequent fourth process, the above-described first cleaning was performed with the edge ring ER held by the electrostatic chuck 22. In the fourth process, a direct current voltage of -4000 V was applied to the first electrode 22a and the second electrode 22b. In the subsequent fifth process, the above-described second cleaning was performed with the edge ring ER held by the electrostatic chuck 22. In addition, in the fourth process and the fifth process, the heat transfer gas from the gas supply mechanism 86 was supplied to the gap between the electrostatic chuck 22 and the edge ring ER. The sixth process is the same process as the process ST6, and the sample substrate was carried onto the electrostatic chuck 21 using the carrying device TU2.

[0081] The conditions of the fourth process and the fifth process in each of the first to sixth experiments are shown.

[0082] First Experiment

[0083] Performance time of the fourth process: 335 seconds

[0084] Applied voltage to the first electrode 22a in the fifth process: 1000 V

[0085] Applied voltage to the second electrode 22b in the fifth process: -4000 V

[0086] Performance time of the fifth process: 25 seconds

[0087] Experiment 2

[0088] Execution time of the 4th process: 35 seconds

[0089] Voltage applied to the 1st electrode 22a in the 5th process: -4000V

[0090] Voltage applied to the 2nd electrode 22b in the 5th process: -4000V

[0091] Execution time of the 5th process: 25 seconds

[0092] Experiment 3

[0093] Execution time of the 4th process: 35 seconds

[0094] Voltage applied to the 1st electrode 22a in the 5th process: 4000V

[0095] Voltage applied to the 2nd electrode 22b in the 5th process: -4000V

[0096] Execution time of the 5th process: 25 seconds

[0097] Experiment 4

[0098] Execution time of the 4th process: 35 seconds

[0099] Voltage applied to the 1st electrode 22a in the 5th process: -3000V

[0100] Voltage applied to the 2nd electrode 22b in the 5th process: -3000V

[0101] Execution time of the 5th process: 25 seconds

[0102] Experiment 5

[0103] Execution time of the 4th process: 35 seconds

[0104] Voltage applied to the 1st electrode 22a in the 5th process: 3000V

[0105] Voltage applied to the 2nd electrode 22b in the 5th process: -3000V

[0106] Execution time of the 5th process: 25 seconds

[0107] Experiment 6

[0108] Execution time of the 4th process: 95 seconds

[0109] Voltage applied to the 1st electrode 22a in the 5th process: 3000V

[0110] The voltage applied to the second electrode 22b in step 5 is -3000V.

[0111] Execution time for step 5: 25 seconds

[0112] In each of the 1st to 6th experiments, after the 6th step, the center position of the sample substrate relative to the reference position on the electrostatic chuck 21 was determined. The reference position is the position on the axis AX. Figure 6 (a) indicates the center position of the sample substrate as determined in Experiment 1. Figure 6 (b) indicates the center position of the sample substrate as determined in Experiment 2. Figure 6 (c) indicates the center position of the sample substrate as determined in Experiment 3. Figure 7 (a) indicates the center position of the sample substrate as determined in experiment 4. Figure 7 (b) indicates the center position of the sample substrate as determined in experiment 5. Figure 7 (c) indicates the center position of the sample substrate as determined in Experiment 6. In these figures, the center position of the sample substrate is expressed as its distance [mm] from the reference positions (coordinates [0, 0]) in two orthogonal horizontal directions.

[0113] like Figure 6 (b) and Figure 6 As shown in (c), in each of the second and third experiments, the offset of the center position of the sample substrate relative to the reference position is large. That is, when the absolute values ​​of the voltages applied to the first electrode 22a and the second electrode 22b are the same in the second, fourth, and fifth steps, the offset of the center position of the sample substrate relative to the reference position is large. Furthermore, as... Figure 7 As shown in (a), in the fourth experiment, the offset of the center position of the sample substrate relative to the reference position was also large. That is, even if the voltages applied to the first electrode 22a and the second electrode 22b have small absolute values ​​in the fifth process, and have the same polarity in the fourth and fifth processes, the offset of the center position of the sample substrate relative to the reference position is still large. Furthermore, as Figure 7 As shown in (b), in the fifth experiment, the offset of the center position of the sample substrate relative to the reference position is small. That is, in the fifth step, when positive and negative voltages, each with a small absolute value, are applied to the first electrode 22a and the second electrode 22b respectively, the offset of the center position of the sample substrate relative to the reference position is small. However, in the sixth experiment, compared to the fifth experiment, only the execution time of the fourth step is extended, but as... Figure 7In the case of (c) shown in FIG. 6, the amount of shift of the center position of the sample substrate from the reference position is large in the 6th experiment. In contrast, in the 1st experiment, the voltage applied to the 1st electrode 22a in the 5th process has a positive polarity. Also, in the 1st experiment, the absolute value of the voltage applied to the 1st electrode 22a in the 5th process is smaller than the absolute value of the voltage applied to the 1st electrode 22a in the 4th process. Also, in the 1st experiment, the absolute value of the voltage applied to the 1st electrode 22a in the 5th process is smaller than the absolute value of the voltage of negative polarity applied to the 2nd electrode 22b in the 5th process. In the 1st experiment, although the execution time of the 4th process is long, as Figure 6 In the case of (a) shown in FIG. 6, the amount of shift of the center position of the sample substrate from the reference position is small. Thus, it is confirmed that, in the case where the voltage applied to the 1st electrode 22a in the process ST5 has a polarity opposite to that of the voltage applied to the 1st electrode 22a in the previous process and has a relatively small absolute value, the misalignment of the substrate can be suppressed.

[0114] Also, the absolute value of the direct current voltage applied to the 1st electrode 22a and the 2nd electrode 22b in the process ST4 of the method MT can be greater than 4000 V. In the process ST4 of the method MT, a direct current voltage can also be applied to the 1st electrode 22a and the 2nd electrode 22b for a longer time (for example, a time of 600 seconds or more). In one example, a direct current voltage of 900 seconds can be applied to the 1st electrode 22a and the 2nd electrode 22b in the process ST4 of the method MT. Also, if the absolute value of the applied voltage to the 1st electrode 22a in the process ST5 of the method MT is less than 4000 V, the shift of the substrate carried onto the electrostatic chuck 21 next is reduced.

[0115] The above describes various exemplary embodiments, but is not limited to the above-described exemplary embodiments, and various additions, omissions, substitutions, and changes can be made. Also, elements in different embodiments can be combined to form other embodiments.

[0116] For example, the plasma processing apparatus to which the method MT is applied can be a plasma processing apparatus different from the plasma processing apparatus 1. In another embodiment, the plasma processing apparatus can be a capacitively coupled plasma processing apparatus different from the plasma processing apparatus 1. In yet another embodiment, the plasma processing apparatus can also be an inductively coupled plasma processing apparatus, an ECR (electron cyclotron resonance) plasma processing apparatus, or a plasma processing apparatus that generates plasma using a surface wave such as a microwave.

[0117] As understood from the above description, the embodiments of the present application are described in the present specification for the purpose of illustration, and various changes can be made without departing from the scope and spirit of the present application. Therefore, the embodiments disclosed in the present specification are not intended to be limiting, and the true scope and spirit can be shown by the scope of the appended technical solutions.

Claims

1. A method for maintaining an edge loop, comprising: In order to perform plasma treatment on a substrate in the chamber of a plasma processing apparatus, the first electrostatic chuck of the substrate support holds the edge ring and applies a first voltage of positive polarity to the first electrode and the second electrode of the first electrostatic chuck. The plasma treatment is performed with the substrate placed on the second electrostatic chuck of the substrate support in the area surrounded by the edge ring. In order to hold the edge ring by the first electrostatic chuck during the first period after the plasma treatment and after the substrate is removed from the chamber, a second voltage with negative polarity is applied to the first electrode and the second electrode, and the cleaning of the chamber is performed using the plasma generated in the chamber during the first period; and In order to hold the edge ring by the first electrostatic chuck during the second period following the first period, a third voltage and a fourth voltage are applied to the first electrode and the second electrode, respectively. During this second period, plasma generated within the chamber is used to perform chamber cleaning. The first electrode extends closer to the second electrostatic chuck than the second electrode. The third voltage has a positive polarity, and the fourth voltage has a negative polarity. The absolute value of the third voltage is less than the absolute values ​​of the first voltage, the second voltage, and the fourth voltage, so that the absolute values ​​of the third voltage and the fourth voltage suppress misalignment of other substrates transported to the second electrostatic chuck after the cleaning of the chamber is performed.

2. The method for retaining the edge ring according to claim 1, wherein, The absolute value of the fourth voltage is equal to the absolute value of the first voltage and the absolute value of the second voltage.

3. The method for retaining the edge ring according to claim 1, wherein, The absolute value of the second voltage is equal to the absolute value of the first voltage.

4. The method for retaining the edge ring according to any one of claims 1 to 3, wherein, The plasma generated during the first period is an oxygen-generated plasma. The plasma generated during the second period is a plasma generated from nitrogen gas.

5. The method for retaining the edge ring according to any one of claims 1 to 3, further comprising: Following the steps of applying the third and fourth voltages, the next step involves transferring another substrate onto the second electrostatic chuck using a transport device. While the other substrate is placed on the second electrostatic chuck, and the edge ring is held by the first electrostatic chuck by applying the first voltage to the first electrode and the second electrode, the plasma treatment is further performed on the other substrate.

6. A plasma processing apparatus, comprising: chamber; A substrate support is configured to support a substrate in the cavity. The substrate support has a first electrostatic chuck configured to hold an edge ring placed thereon and a second electrostatic chuck configured to hold the substrate placed thereon. The first electrostatic chuck has a first electrode and a second electrode, the first electrode extending closer to the second electrostatic chuck than the second electrode. A power supply device, comprising one or more DC power supplies, configured to generate a voltage applied to the first electrode and the second electrode; and The control unit is configured to control the power supply device. The control unit performs the following controls: The power supply device is controlled to apply a first voltage of positive polarity to the first electrode and the second electrode in order to hold the edge ring by the first electrostatic chuck during plasma treatment of the substrate placed on the second electrostatic chuck. The power supply device is controlled to apply a second voltage of negative polarity to the first electrode and the second electrode so that the edge ring is held by the first electrostatic chuck during the first period of cleaning of the chamber using the plasma generated in the chamber after the plasma treatment and after the substrate is removed from the chamber; and The power supply is controlled such that, in order to hold the edge ring by the first electrostatic chuck during a second period of cleaning the chamber using plasma generated within the chamber after the first period, a third voltage is applied to the first electrode, and a fourth voltage is applied to the second electrode. The third voltage has a positive polarity, and the fourth voltage has a negative polarity. The absolute value of the third voltage is less than the absolute values ​​of the first voltage, the second voltage, and the fourth voltage, so that the absolute values ​​of the third voltage and the fourth voltage suppress misalignment of other substrates transported to the second electrostatic chuck after the cleaning of the chamber is performed.

7. The plasma processing apparatus according to claim 6, wherein, The absolute value of the fourth voltage is equal to the absolute value of the first voltage and the absolute value of the second voltage.

8. The plasma processing apparatus according to claim 6 or 7, wherein, The absolute value of the second voltage is equal to the absolute value of the first voltage.

9. A substrate processing system comprising: The plasma processing apparatus according to any one of claims 6 to 8; and Handling device, The control unit performs the following controls: Control the transport device to transport another substrate onto the second electrostatic chuck after the cleaning is performed during the second phase; and The power supply device is controlled to apply the first voltage to the first electrode and the second electrode in order to hold the edge ring by the first electrostatic chuck during the plasma treatment of the other substrate placed on the second electrostatic chuck.

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