Substrate support and substrate processing device

Abstract

A substrate support according to the present invention comprises a fixed-side member and a moving-side member that moves with respect to the fixed-side member. The moving-side member has a first stage having a support surface for supporting the substrate, and a first electrode disposed in the first stage. The fixed-side member has a second stage disposed below the first stage so as to form a gap with the first stage, and a second electrode disposed in the second stage. The first electrode and the second electrode are electrically coupled by an ionic liquid disposed in the gap. Conductive fine particles are mixed in the ionic liquid.

Description

Substrate support and substrate processing apparatus

[0001] Various aspects and embodiments of this disclosure relate to substrate supports and substrate processing devices.

[0002] Patent Document 1 discloses a substrate support unit provided within a processing chamber for processing substrates, having a rotation axis centered at the center of the processing chamber and configured to be rotatable. The rotation mechanism for rotating the substrate support unit is configured as a slip ring mechanism that electrically connects the rotating side and the stationary side using metal brushes or the like.

[0003] Japanese Patent Publication No. 2015-185757

[0004] The technology disclosed herein provides a substrate support and a substrate processing apparatus that can supply power to an electrode provided on the moving side without mechanical contact between the moving side and the stationary side, in a substrate support equipped with a moving mechanism.

[0005] One aspect of this disclosure is a substrate support comprising a fixed-side member and a movable-side member that moves relative to the fixed-side member. The movable-side member has a first stage having a support surface for supporting a substrate and a first electrode disposed within the first stage. The fixed-side member has a second stage disposed below the first stage so as to form a gap between it and the first stage, and a second electrode disposed within the second stage. The first electrode and the second electrode are electrically coupled by an ionic liquid disposed in the gap. Conductive fine particles are mixed into the ionic liquid.

[0006] According to various aspects and embodiments of this disclosure, in a substrate support equipped with a moving mechanism, power can be supplied to an electrode provided on the moving side without mechanical contact between the moving side and the fixed side.

[0007] FIG. 1 is a diagram showing an example of a substrate processing system in an embodiment of the present disclosure. FIG. 2 is a diagram showing an example of a substrate support. FIG. 3 is a schematic diagram showing an example of an electrical connection of the substrate support. FIG. 4 is a diagram showing an example of a rotation mechanism. FIG. 5 is a diagram showing an example of a measurement system used in an experiment. FIG. 6 is a diagram showing an example of an equivalent circuit of the measurement system. FIG. 7A is a diagram showing an example of a time change of a potential difference between electrodes. FIG. 7B is a diagram showing an example of a time change of a potential difference between electrodes. FIG. 7C is a diagram showing an example of a time change of a potential difference between electrodes. FIG. 8 is a diagram showing an example of a final potential difference between electrodes.

[0008] Hereinafter, embodiments of the disclosed substrate support and substrate processing apparatus will be described in detail based on the drawings. Note that the disclosed substrate support and substrate processing apparatus are not limited by the following embodiments.

[0009] By the way, some substrate processing apparatuses include a substrate processing apparatus provided with a moving mechanism for precisely moving a substrate while holding the substrate. For the moving mechanism for moving the substrate, for example, a slip ring mechanism that slides a metal brush on the fixed side and an electrode on the moving side for electrically connecting between the moving side including the substrate mounting surface and the fixed side fixed to the processing container may be used.

[0010] However, when performing electrical connection between the moving side and the fixed side using such a slip ring mechanism, wear powder (hereinafter referred to as "particles") is generated due to the sliding of the electrode and the metal brush, and this particles may cause problems in substrate processing. In addition, since the electrode and the metal brush are worn by sliding, such a slip ring mechanism needs to be replaced at regular intervals, and there is a concern about an increase in the maintenance frequency and downtime of the semiconductor manufacturing apparatus.

[0011] The present disclosure provides a technique capable of supplying power to an electrode provided on a moving side without mechanical contact between the moving side and the fixed side in a substrate support provided with a moving mechanism.

[0012] [Substrate Processing System] FIG. 1 is a diagram showing an example of a substrate processing system according to an embodiment of the present disclosure. In the following description, an example will be described in which the substrate processing system includes a substrate processing apparatus 1 as a plasma processing apparatus that performs plasma processing such as film formation processing and etching processing on a substrate W in a vacuum (reduced pressure) environment.

[0013] The substrate processing system includes a substrate processing apparatus 1 and a control unit 2. The substrate processing apparatus 1 has a processing chamber 10, a substrate supporter 20, a gas supply unit 40, a power supply 50, an exhaust unit 60, and an ionic liquid supply unit 70. The substrate supporter 20 is disposed in the processing chamber 10. The substrate processing apparatus 1 also includes a dielectric window 11, an antenna 12, and a gas introduction unit. The dielectric window 11 constitutes at least a part of the ceiling of the processing chamber 10. The antenna 12 is disposed above or over the processing chamber 10 (that is, above or over the dielectric window 11). The processing chamber 10 has a processing space 10s defined by the dielectric window 11, the substrate supporter 20, and the side wall of the processing chamber 10. The processing chamber 10 is grounded.

[0014] The antenna 12 includes one or more coils. In one embodiment, the antenna 12 may include an outer coil and an inner coil disposed coaxially. In this case, an RF power supply 51 described later may be connected to both the outer coil and the inner coil, or may be connected to either one of the outer coil and the inner coil.

[0015] The gas introduction unit is configured to introduce at least one processing gas from the gas supply unit 40 into the processing space 10s. In one embodiment, the gas introduction unit includes a central gas injection unit (CGI: Center Gas Injector) 13. The central gas injection unit 13 is disposed above the substrate supporter 20 and attached to a central opening formed in the dielectric window 11. Note that the gas introduction unit may include, in addition to or instead of the central gas injection unit 13, one or more side gas injection units (SGI: Side Gas Injector) attached to one or more openings formed in the side wall of the processing chamber 10.

[0016] The processing chamber 10 is formed in a substantially cylindrical shape and is configured to maintain a vacuum (reduced pressure) state inside. A substrate support 20, which will be described later, is positioned approximately in the center of the bottom surface of the processing chamber 10.

[0017] The substrate support 20 includes an electrostatic chuck 21 and a base 22. The electrostatic chuck 21 has one or more substrate support surfaces for supporting the substrate W to be processed. The electrostatic chuck 21 may be configured to support only one substrate W, or it may be configured to support multiple substrates W simultaneously. The electrostatic chuck 21 may further have a ring support surface (not shown) for supporting a ring assembly R that is arranged to surround the substrate W during plasma processing. The ring assembly R may include one or more edge rings and at least one covering ring. The base 22 supports the electrostatic chuck 21 from below. The detailed configuration of the substrate support 20 will be described later.

[0018] The gas supply unit 40 may include at least one gas source 41 and at least one flow controller 42. In one embodiment, the gas supply unit 40 is configured to supply at least one processing gas to the processing space 10s from a corresponding gas source 41 via a corresponding flow controller 42. Each flow controller 42 may include, for example, a mass flow controller or a pressure-controlled flow controller. Furthermore, the gas supply unit 40 may include one or more flow modulation devices that modulate or pulse the flow rate of at least one processing gas.

[0019] The power supply 50 includes an RF power supply 51 coupled to the processing chamber 10 via at least one impedance matching circuit. The RF power supply 51 is coupled to the antenna 12 via at least one impedance matching circuit and is configured to supply an RF signal (RF power) for plasma generation to the antenna 12. In one embodiment, the RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the RF power supply 51 may be configured to generate a plurality of RF signals having different frequencies. One or more generated RF signals are supplied to the antenna 12. This causes plasma to be formed from at least one processing gas supplied from the gas supply unit 40 to the processing space 10s.

[0020] Furthermore, the power supply 50 may include a DC (Direct Current) power supply 52 coupled to the electrode 21b, which will be described later, located inside the electrostatic chuck 21, and the motor 27b of the rotating mechanism 27, which will be described later. By applying a voltage from the DC power supply 52 to the electrode 21b, an electrostatic force such as Coulomb force is generated, and the substrate W is attracted and held on the substrate support surface of the electrostatic chuck 21 by the generated electrostatic force. Therefore, the electrode 21b, which will be described later and located inside the electrostatic chuck 21, can be an electrostatic electrode. Also, by applying a voltage from the DC power supply 52 to the motor 27b, the rotating mechanism 27 can be rotated.

[0021] In this embodiment, the power supply 50 is coupled to the antenna 12, the electrode 21b, and the motor 27b, respectively. However, in other examples, the RF power supply 51 coupled to the antenna 12 and the DC power supply 52 coupled to the electrode 21b and the motor 27b may be arranged independently. Furthermore, the DC power supply for substrate adsorption coupled to the electrode 21b and the DC power supply for rotation coupled to the motor 27b may be arranged independently.

[0022] The exhaust section 60 may be connected to, for example, a gas outlet 10e located at the bottom of the processing chamber 10. The exhaust section 60 may include a pressure regulating valve and a vacuum pump. The pressure regulating valve regulates the pressure in the processing space 10s. The vacuum pump may include a turbomolecular pump, a dry pump, a rotary pump, or a combination thereof.

[0023] The ionic liquid supply unit 70 is connected to the lower part of the processing chamber 10, for example, through through holes 10a and 10b formed in the bottom of the processing chamber 10. Through hole 10a is connected to an ionic liquid supply port 71, which will be described later, and through hole 10b is connected to an ionic liquid outlet 72, which will be described later. The ionic liquid supply unit 70 also includes an ionic liquid supply source 73 that stores the ionic liquid inside, which will be described later. As described later, the ionic liquid supply unit 70 is configured to circulate the ionic liquid in the ionic liquid supply source 73 to the substrate support 20 via the ionic liquid supply port 71 and the ionic liquid outlet 72. Through hole 10a is an example of a first piping, and through hole 10b is an example of a second piping.

[0024] The control unit 2 processes computer-executable instructions that cause the substrate processing apparatus 1 to perform various processes described herein. The control unit 2 may be configured to control each element of the substrate processing apparatus 1 to perform the various processes described herein. In one embodiment, part or all of the control unit 2 may be included in the substrate processing apparatus 1. The control unit 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 is implemented, for example, by a computer 2a. The processing unit 2a1 may be configured to perform various control operations by reading a program from the storage unit 2a2 and executing the read program. This program may be stored in the storage unit 2a2 in advance, or it may be obtained via a medium when needed. The obtained program is stored in the storage unit 2a2 and read from the storage unit 2a2 and executed by the processing unit 2a1. The medium may be various storage media readable by the computer 2a, or it may be a communication line connected to the communication interface 2a3. The processing unit 2a1 may be, for example, a CPU (Central Processing Unit). The storage unit 2a2 may include, for example, RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 may communicate with the substrate processing device 1 via a communication line such as a LAN (Local Area Network).

[0025] [Substrate Support 20] Figure 2 shows an example of a substrate support 20. Figure 3 is a schematic diagram showing an example of the electrical connections of the substrate support 20. The electrostatic chuck 21 includes a ceramic member 21a and electrodes 21b disposed within the ceramic member 21a. The electrodes 21b include an inner electrode 21b1 and an outer electrode 21b2. The ceramic member 21a has a substrate support surface. One or more substrates W to be processed are placed on the upper surface of the electrostatic chuck 21 in the processing chamber 10.

[0026] The base 22 includes a rotating stage 23 and a fixed stage 24, as shown in Figure 2, for example. The rotating stage 23 is an example of a first stage, and the fixed stage 24 is an example of a second stage. The rotating stage 23 is located on the electrostatic chuck 21 side, i.e., the upper side, of the base 22, and the fixed stage 24 is located on the bottom side of the processing chamber 10, i.e., the lower side, of the base 22. Furthermore, the fixed stage 24 is positioned so as not to mechanically contact the rotating stage 23, i.e., a gap G is formed between the rotating stage 23 and the fixed stage 24. In the following description, the "electrostatic chuck 21" and the "rotating stage 23" may be collectively referred to as the "first stage." Therefore, the first stage has a substrate support surface.

[0027] A rotating shaft 25, which substantially coincides with the center of the rotating stage 23 in a plan view, is connected to the lower part of the rotating stage 23 via an insulating component 26. The lower part of the rotating shaft 25 is positioned below the rotating stage 23 and is immersed in an ionic liquid L1, which will be described later, located in an insulator 30, which will be described later, located in the central part of the fixed stage 24.

[0028] An opening 24a is formed approximately in the center of the fixed stage 24. An insulator 30 is fitted inside the opening 24a (radially inward), with a recess 30a in which the aforementioned rotating shaft 25 is positioned. The insulator 30 has a roughly box-like shape with an opening on its upper surface in cross-section. An ionic liquid L1, described later, is placed inside the recess 30a of the insulator 30. The ionic liquid L1 filling the recess 30a is electrically isolated from the fixed stage 24 via the insulator 30. The rotating shaft 25 of the rotating stage 23 is inserted and positioned inside the recess 30a so as to be immersed in the ionic liquid L1.

[0029] Furthermore, a rotation mechanism 27 for rotating the rotation shaft 25 around a vertical axis is provided inside the base 22 of the substrate support 20. As described above, since the rotation shaft 25 is connected to the rotation stage 23 via an insulating component 26, the rotation stage 23 and the electrostatic chuck 21 on it are configured to rotate integrally with the rotation shaft 25 around a vertical axis by the rotation mechanism 27. The electrostatic chuck 21, the rotation stage 23, and the rotation shaft 25 are examples of movable members, while the fixed stage 24 and the insulator 30 are examples of fixed members.

[0030] The rotating mechanism 27 may be a variable speed mechanism capable of controlling the rotational speed. In one embodiment, the rotating mechanism 27 includes, for example, a permanent magnet 27a, which is a rotor, arranged on a rotating stage 23, which is the rotating side (moving side), and a motor 27b, which is arranged on a stationary stage 24, which is the stationary side, on the inner circumference side of the permanent magnet 27a, as shown in Figure 4. The permanent magnet 27a has a substantially annular shape with N poles and S poles arranged alternately in the circumferential direction. The motor 27b comprises a plurality of coils C. A DC power supply 52 is coupled to the motor 27b (specifically, each of the plurality of coils C) as described above. The rotating mechanism 27 is composed of a so-called BL (Brushless) DC motor that rotates the permanent magnet 27a without contact by magnetic flux generated by the application of voltage from the DC power supply 52 to the coils.

[0031] Furthermore, the rotating shaft 25 is made of a conductive material and is coupled to the inner electrode 21b1 via wiring 250. The inner electrode 21b1 is electrically coupled to the ionic liquid L1 via wiring 250 and the rotating shaft 25. The insulator 30 is provided with a ring-shaped electrode 280 made of a conductive material, and the electrode 280 is in contact with the ionic liquid L1. The electrode 280 is connected to the DC power supply 52 via wiring 28. Since the ionic liquid L1 is conductive, the electrode 280 is electrically coupled to the rotating shaft 25 via the ionic liquid L1. The rotating shaft 25 is an example of a first electrode, and the electrode 280 is an example of a second electrode.

[0032] The ionic liquid L1 is placed inside the recess 30a of the insulator 30 in the central part of the substrate support 20, as shown in Figure 2, for example. The amount of ionic liquid L1 filled is determined so that at least the bottom surface and some of the sides of the rotating shaft 25 on the rotating side, and the entire cross-section of the electrode 280 on the stationary side are immersed in the ionic liquid L1. Accordingly, the DC power supply 52 is electrically coupled to the inner electrode 21b1 via the wiring 28, electrode 280, ionic liquid L1, rotating shaft 25, and wiring 250, as shown in Figure 3, for example.

[0033] The ionic liquid L2 is supplied to the gap G between the rotating stage 23 and the stationary stage 24 on the outer periphery of the substrate support 20, as shown in Figure 2, for example. The ionic liquid L2 is also supplied to the gap G from an ionic liquid supply port 71 formed on the lower side of the stationary stage 24 and discharged from an ionic liquid outlet 72 to an ionic liquid supply source 73 located outside the processing chamber 10, for example. In this embodiment, the ionic liquid L2 is configured to circulate through the ionic liquid supply port 71 and the ionic liquid outlet 72.

[0034] The ionic liquid L2 is supplied to the gap G from at least two locations, a first supply position P1 and a second supply position P2, as shown in Figure 2, for example. The first supply position P1 is a supply position that supplies the ionic liquid L2 to the rotating stage 23 from below (in the vertical direction), and the second supply position P2 is a supply position that supplies the ionic liquid L2 to the rotating stage 23 from the side (in the horizontal direction). The first supply position P1 and the second supply position P2 are, in one example, annular supply ports formed around the entire circumference of the fixed stage 24 in a plan view.

[0035] In the substrate support 20 of this embodiment, a gap G is formed between the rotating stage 23 and the fixed stage 24, and the rotating stage 23 and the fixed stage 24 are configured not to come into mechanical contact. However, for example, the position of the rotating stage 23 may change due to axial misalignment or its own weight accompanying the rotation of the rotating stage 23, and there is a risk that it may come into mechanical contact with the fixed stage 24.

[0036] Therefore, in the substrate support 20 of this embodiment, as described above, the ionic liquid L2 is supplied to the rotating stage 23 from at least two directions, vertical and horizontal. As a result, the stress acting on the rotating stage 23 due to the supply of the ionic liquid L2 (the impact force of the ionic liquid L2 on the rotating stage 23) maintains the posture of the rotating stage 23, and mechanical contact between the rotating stage 23 and the stationary stage 24 can be appropriately suppressed.

[0037] In this embodiment, the ionic liquid L1 is pre-placed in the recess 30a and the ionic liquid L2 circulates with the ionic liquid supply source 73, but the disclosed technology is not limited to this. As another example, if mechanical contact between the rotating stage 23 and the stationary stage 24 due to rotation can be appropriately suppressed, the ionic liquid L2 may be pre-placed in the gap G instead of circulating with the ionic liquid supply source 73. Alternatively, the ionic liquid L1 may also be configured to circulate with the ionic liquid supply source 73.

[0038] Furthermore, a buffer space B capable of temporarily storing the ionic liquid L2 may be formed between the rotating stage 23 and the stationary stage 24 in order to prevent leakage of the ionic liquid L2 discharged from the ionic liquid outlet 72 into the processing chamber 10.

[0039] One end of the wiring 290 is electrically coupled to the outer electrode 21b2, and the other end of the wiring 290 is exposed to the gap G where the ionic liquid L2 is placed. As a result, the other end of the wiring 290 is electrically coupled to the ionic liquid L2. Also, one end of the wiring 29 is exposed to the gap G where the ionic liquid L2 is placed, and the other end is electrically coupled to the ground potential, for example, the processing chamber 10. Therefore, the outer electrode 21b2 is electrically coupled to the ground potential via the wiring 290, the ionic liquid L2, and the wiring 29, as shown in Figure 3, for example.

[0040] In the substrate support 20 of this embodiment, if the rotating wiring (wiring 250 and rotating shaft 25) and the fixed wiring (electrode 280 and wiring 28) are brought into mechanical contact, for example, in a slip ring mechanism, there are concerns about particle generation and wear of the wiring.

[0041] In contrast, in the substrate support 20 of this embodiment, instead of mechanically contacting the rotating wiring and the stationary wiring, ionic liquids L1 and L2 are interposed between them to achieve electrical coupling between the rotating wiring and the stationary wiring. This suppresses the generation of wear particles when supplying power to the electrostatic chuck 21. As a result, the adhesion of wear particles to the substrate W to be processed and the electrostatic chuck 21 is suppressed, and the occurrence of defects in substrate processing caused by such wear particles can be suppressed.

[0042] Furthermore, in the substrate support 20 of this embodiment, there is no mechanical contact between the moving wiring and the fixed wiring, thus suppressing wear (consumption) of these wirings. This reduces the frequency of maintenance of the substrate processing apparatus 1 due to the replacement of wiring arranged in the substrate support 20, thereby reducing the downtime of the substrate processing apparatus 1.

[0043] Furthermore, ionic liquids are generally used as lubricants to improve the lubricity of metal contact surfaces. Therefore, as described above, by interposing an ionic liquid between the rotating stage 23 and the fixed stage 24 in the substrate support 20, the rotation of the rotating stage 23 relative to the fixed stage 24 can be made smoother, and the rotation of the substrate W during substrate processing can be precisely controlled.

[0044] Furthermore, ionic liquids are generally known to have low volatility and exist as liquids in a vacuum. Therefore, the ionic liquids L1 and L2 do not volatilize inside the processing chamber 10 where the substrate W is processed in a vacuum environment, allowing for the electrical connection of the rotating shaft 25 and the electrode 280, and the electrical connection of the wiring 290 and the wiring 29. In addition, power can be supplied to the electrode 21b and static electricity can be removed from the electrostatic chuck 21.

[0045] Furthermore, according to the substrate support 20 of this embodiment, the rotation mechanism 27 for rotating the rotating stage 23 is located inside the substrate support 20 and does not need to be located outside the processing chamber 10. Therefore, the entire mechanism, which suppresses particle generation compared to conventional slip ring mechanisms, can be introduced inside the processing chamber 10. As a result, there is no need to provide a vacuum seal or magnetic seal for inserting the rotating shaft 25 into the processing chamber 10, and the vertical space of the substrate processing apparatus 1 can be reduced.

[0046] Furthermore, the ionic liquid in this embodiment is mixed with unoxidized metal nanoparticles (hereinafter sometimes referred to as metal nanoparticles). Metal nanoparticles are an example of conductive nanoparticles. The ionic liquid portion excluding the metal nanoparticles (hereinafter simply referred to as ionic liquid) has the following properties, for example. Ionic liquids are ionic compounds that are liquid at room temperature and are also called room-temperature molten salts. Ionic liquids have characteristics such as a vapor pressure of almost zero and non-volatility (they do not volatilize even at high temperatures or in a vacuum). Ionic liquids are composed of cations and anions.

[0047] Examples of cations that constitute ionic liquids include pyridinium, imidazolium, ammonium, pyrrolidinium, and piperidinium cations containing nitrogen, as well as phosphonium cations containing phosphorus. These cations have alkyl groups [-(CH4)] as side chains. ２ ) ｎ CH ３ This includes, for example, morphonium-type and sulfonium-type cations that make up ionic liquids.

[0048] Examples of pyridinium-type cations include C, represented by the chemical formula (C1-1) as shown below. ２ py ＋ , C represented by the chemical formula (C1-2) ４ py ＋ These are some examples. However, pyridinium-type cations are not limited to these.

[0049] ​

[0050] As imidazolium-type cations, for example, as shown below, C represented by the chemical formula (C2-1) ２ mim ＋ , C represented by the chemical formula (C2-2) ４ mim ＋ , C represented by the chemical formula (C2-3) ６ mim ＋ , C represented by the chemical formula (C2-4) ８ mim ＋ may be mentioned. However, imidazolium-type cations are not limited to these.

[0051]

[0052] As ammonium-type cations, for example, as shown below, N represented by the chemical formula (C3-1) ３，１，１，１ ＋ , N represented by the chemical formula (C3-2) ４，１，１，１ ＋ , N represented by the chemical formula (C3-3) ６，１，１，１ ＋ , N represented by the chemical formula (C3-4) ２，２，１，（２Ｏ１） ＋ , Ch represented by the chemical formula (C3-5) ＋ may be mentioned. However, ammonium-type cations are not limited to these.

[0053]

[0054] As pyrrolidinium-type cations, for example, as shown below, Pyr represented by the chemical formula (C4-1) １，３ ＋ , Pyr represented by the chemical formula (C4-2) １，４ ＋ may be mentioned. However, pyrrolidinium-type cations are not limited to these.

[0055]

[0056] As piperidinium-type cations, for example, as shown below, Pip represented by the chemical formula (C5-1) １，３ ＋ , Pip represented by the chemical formula (C5-2)１，４ ＋ These are some examples. However, piperidinium-type cations are not limited to these.

[0057]

[0058] As an example of a phosphonium-type cation, P is represented by the chemical formula (C6-1) as shown below. ５，２，２，２ ＋ P, represented by the chemical formula (C6-2) ６，６，６，１４ ＋ These are some examples. However, phosphonium-type cations are not limited to these.

[0059]

[0060] An anion that makes up an ionic liquid is, for example, TfO, represented by chemical formula (A1) as shown below. － , Tf represented by chemical formula (A2) ２ N － (TFSA) － ), Tf represented by chemical formula (A3) ３ C － FSA represented by chemical formula (A4) － CH, represented by chemical formula (A5) ３ COO － CF, represented by chemical formula (A6) ３ COO － , represented by chemical formula (A7) BF ４ － PF represented by chemical formula (A8) ６ － (CN), represented by the chemical formula (A9) ２ N － AlCl, represented by the chemical formula (A10) ４ － Al, represented by chemical formula (A11) ２ Cl ７ － These are some examples. However, the anions that make up ionic liquids are not limited to these. In addition, other anions that make up ionic liquids include PF ６ － , Cl － This can also be mentioned. ​​

[0061]

[0062] Specific examples of ionic liquids include N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide (DEME / TFSA) and 1-ethyl-3-methylimidazolium dicyanamide.

[0063] In this embodiment, ionic liquids L1 and L2 are mixed with unoxidized metal nanoparticles. Ionic liquids L1 and L2 are preferably hydrophilic, similar to water. This ensures that the surface of the metal nanoparticles is constantly wetted by the ionic liquid, thus preventing oxidation of the metal nanoparticles. Furthermore, the metal nanoparticles in this embodiment are composed of unoxidized metals such as stainless steel. The metal nanoparticles may also be composed of stainless steel, titanium, aluminum, nickel, or alloys thereof.

[0064] The smaller the metal nanoparticles mixed in ionic liquid L1 and ionic liquid L2, the less likely they are to aggregate. Therefore, in this embodiment, the diameter of the metal nanoparticles is, for example, in the range of 1 nm to 100 nm. Preferably, the diameter of the metal nanoparticles is, for example, in the range of 1 nm to 50 nm.

[0065] From the viewpoint of enhancing conductivity, the concentration of metal fine particles in ionic liquid L1 and ionic liquid L2 is preferably high enough so as not to cause aggregation. In this embodiment, the concentration of metal fine particles in ionic liquid L1 and ionic liquid L2 is, for example, 10 mmol / dm 3 ~500mmol / dm 3 The concentration is within the range of [specify range]. Preferably, the concentration of metal particles in ionic liquid L1 and ionic liquid L2 is 50 mmol / dm³. 3 ~100mmol / dm 3 The concentration is within the specified range.

[0066] ​The viscosity of ionic liquids L1 and L2 changes with temperature. Therefore, the temperatures of ionic liquids L1 and L2 are selected considering the heat generated by the dynamic characteristics of the mechanism and the characteristics of the mechanism's motion (rotational / linear / stationary). In this embodiment, the temperatures of ionic liquids L1 and L2 are within the range of -10°C to 80°C.

[0067] [Experiment using ionic liquid L] Next, an experiment was conducted with ionic liquid L mixed with metal nanoparticles. Figure 5 shows an example of the measurement system 80 used in the experiment. Figure 6 shows an example of the equivalent circuit of the measurement system 80. In the measurement system 80, for example as shown in Figure 5, a container is filled with ionic liquid L to a depth H, and two electrodes 83a and 83b, spaced d apart, are submerged in the ionic liquid L to a depth h. A DC voltage is applied to electrode 83a from a power supply 82. Electrode 83b is connected to an electrode pad 841 in an electrostatic chuck 84. The electrostatic chuck 84 has a dielectric 840 and electrode pads 841 and 842 provided within the dielectric 840. Electrode pad 842 is connected to ground potential. A substrate W is placed on the electrostatic chuck 84.

[0068] In the experiment, voltages of 2kV, 3kV, and 4kV were applied to electrode 83a from power supply 82, and the potential difference ΔV between the two electrodes 83a and 83b across the ionic liquid L was measured by measuring instrument 81. N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide (DEME・TFSA) was used as the ionic liquid L. Other experimental conditions were as follows: Spacing d = 1 mm, Depth h = 5 mm, Depth H = 8 mm, Immersion surface area of ​​electrodes 83a and 83b = 108 mm². 2 Weight of ionic liquid L = 2.8 g

[0069] Figures 7A to 7C show examples of the time evolution of the potential difference between electrodes 83a and 83b. Figure 7A shows an example of the time evolution of the potential difference when a voltage of 2kV is applied to electrode 83a. Figure 7B shows an example of the time evolution of the potential difference when a voltage of 3kV is applied to electrode 83a. Figure 7C shows an example of the time evolution of the potential difference when a voltage of 4kV is applied to electrode 83a.

[0070] Referring to Figures 7A to 7C, regardless of the magnitude of the voltage applied to electrode 83a, the ionic liquid L mixed with metal nanoparticles shows a faster and more stable change in the time evolution of the potential difference between electrode 83a and electrode 83b compared to the ionic liquid L without metal nanoparticles. The reason why the change in the time evolution of the potential difference stabilizes earlier is thought to be that the dielectric constant of the ionic liquid L decreases due to the mixing of metal nanoparticles, resulting in a lower capacitance than when metal nanoparticles are not mixed. Therefore, in the substrate support 20 of this embodiment, by using ionic liquids L1 and L2 mixed with metal nanoparticles, a predetermined potential difference can be quickly formed between the inner electrode 21b1 and the outer electrode 21b2 in the electrostatic chuck 21. As a result, the substrate W can be quickly adsorbed in the electrostatic chuck 21 of the substrate support 20.

[0071] Furthermore, because the potential difference between electrode 83a and electrode 83b rises quickly, it is expected that the potential difference between electrode 83a and electrode 83b will also fall quickly when the voltage applied to electrode 83a is changed to 0V. When the potential difference between electrode 83a and electrode 83b falls quickly, it becomes possible to quickly de-chuck the substrate W. Therefore, in the substrate support 20 of this embodiment, by using ionic liquids L1 and L2 mixed with metal fine particles, the potential difference between the inner electrode 21b1 and the outer electrode 21b2 in the electrostatic chuck 21 can be rapidly reduced. As a result, the time required for adsorption and de-adsorption of the substrate W in the electrostatic chuck 21 of the substrate support 20 can be shortened.

[0072] Figure 8 shows an example of the final potential difference between electrode 83a and electrode 83b. In Figure 8, the value of the potential difference at the point when the time change of the potential difference between electrode 83a and electrode 83b stabilizes is shown as an example. Referring to Figure 8, in all cases of the voltage applied to electrode 83a, the final potential difference between electrode 83a and electrode 83b is smaller for the ionic liquid L mixed with metal nanoparticles than for the ionic liquid L not mixed with metal nanoparticles.

[0073] When the potential difference between electrode 83a and electrode 83b becomes large, the ionic liquid L placed between electrode 83a and electrode 83b may decompose and deteriorate. In contrast, with ionic liquid L mixed with metal nanoparticles, the potential difference between electrode 83a and electrode 83b can be reduced. Therefore, in the substrate support 20, deterioration of ionic liquid L1 and ionic liquid L2 can be suppressed by using ionic liquid L1 and ionic liquid L2 mixed with metal nanoparticles.

[0074] [Other] The technology disclosed in this application is not limited to the embodiments described above, and numerous modifications are possible within the scope of its essence.

[0075] For example, in the embodiment described above, a rotating stage 23, which is an example of a moving member, rotates relative to a fixed stage 24, which is an example of a fixed member, but the disclosed technology is not limited to this. The disclosed technology can be applied as long as an ionic liquid L containing metal fine particles is placed in the gap between the fixed member and the moving member that moves relative to the fixed member, and the fixed member and the moving member are electrically coupled via the ionic liquid L. For example, the disclosed technology can also be applied to a configuration in which the moving member moves along a slide groove provided in the fixed member, an ionic liquid L is placed in the slide groove, and the fixed member and the moving member are electrically coupled via the ionic liquid L. In this case, a gap in which the ionic liquid L is placed in the slide groove may be formed between the fixed member and the moving member, for example, using a repulsive force due to magnetism.

[0076] Furthermore, in the embodiments described above, unoxidized metal nanoparticles are mixed into ionic liquid L1 and ionic liquid L2, but the disclosed technology is not limited to this. The nanoparticles mixed into ionic liquid L1 and ionic liquid L2 may be non-metallic nanoparticles, as long as they are conductive. Examples of conductive substances other than metals include carbon, conductive polymer particles, and emulsions of even more conductive ionic liquids that do not mix with each other.

[0077] Furthermore, in the above-described embodiment, the ionic liquid supply source 73 may be configured to control the temperature of the ionic liquid L2. In this case, the rotating stage 23 can be cooled or heated to a desired temperature by circulating the temperature-controlled ionic liquid L2. When cooling or heating the rotating stage 23 to a desired temperature, the ionic liquid supply source 73 may be further configured to control the temperature of the ionic liquid L1. This can improve the uniformity of the temperature distribution of the rotating stage 23.

[0078] Furthermore, although the above-described embodiments have explained the case in which the substrate processing apparatus uses an inductively coupled plasma source (ICP), the disclosed technology is not limited to this. In addition to the inductively coupled type, capacitively coupled plasma (CCP), electro-cyclotron-resonance plasma (ECR plasma), helicon wave plasma (HWP), or surface wave plasma (SWP) may be used as the plasma source. Also, various types of plasma generation units, including AC (Alternating Current) plasma generation units and DC plasma generation units, may be used. In one embodiment, the AC signal (AC power) used in the AC plasma generation unit has a frequency in the range of 100 kHz to 10 GHz. Therefore, the AC signal includes an RF (Radio Frequency) signal and a microwave signal. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0079] Furthermore, although the above-described embodiment has been explained using the example of a substrate processing apparatus 1 that performs plasma processing on a substrate W under a reduced pressure environment, the disclosed technology is not limited to this. As another example, the substrate processing apparatus 1 may be a device that performs processing other than plasma processing on a substrate W under a reduced pressure environment. Alternatively, the substrate processing apparatus 1 may be a device that performs processing on a substrate W under atmospheric pressure.

[0080] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. Indeed, the embodiments described above can be embodied in a variety of forms. Furthermore, the embodiments described above may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the attached claims.

[0081] Furthermore, the following additional information is disclosed regarding each of the above embodiments.

[0082] (Note 1) A substrate support comprising a fixed-side member and a movable-side member that moves relative to the fixed-side member, wherein the movable-side member has a first stage having a support surface for supporting a substrate and a first electrode disposed within the first stage, the fixed-side member has a second stage disposed below the first stage so as to form a gap with the first stage and a second electrode disposed within the second stage, the first electrode and the second electrode are electrically coupled by an ionic liquid disposed in the gap, and the ionic liquid is mixed with conductive fine particles. (Note 2) The substrate support according to Note 1, wherein the movable-side member rotates about a rotation axis provided on the fixed-side member. (Note 3) The substrate support according to Note 1 or 2, wherein the conductive fine particles are fine particles composed of stainless steel, titanium, aluminum, nickel, or an alloy thereof. (Note 4) The substrate support according to any one of Notes 1 to 3, wherein the diameter of the conductive fine particles is in the range of 1 nm to 100 nm. (Note 5) The concentration of the conductive fine particles in the ionic liquid is 10 mmol / dm 3 ~500mmol / dm3 A substrate support according to any one of the appendices 1 to 4, wherein the concentration is within the range of (Appendix 6). A substrate support according to any one of the appendices 1 to 5, wherein the temperature of the ionic liquid is within the range of -10°C to 80°C. (Appendix 7) A substrate support according to any one of the appendices 1 to 6, further comprising: a first pipe connected to the gap and supplying the ionic liquid to the gap; a second pipe connected to the gap and discharging the ionic liquid from the gap; and an ionic liquid supply source for circulating the ionic liquid disposed in the gap via the first and second pipes. (Appendix 8) A substrate support according to any one of the appendices 1 to 7, wherein the ionic liquid comprises at least one selected from N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide and 1-ethyl-3-methylimidazolium dicyanamide. (Note 9) A substrate processing apparatus comprising a processing chamber and a substrate support disposed within the processing chamber and supporting a substrate, wherein the substrate support has a fixed side member and a movable side member that moves relative to the fixed side member, the movable side member includes a first stage having a support surface for supporting the substrate and a first electrode disposed within the first stage, the fixed side member includes a second stage disposed below the first stage so as to form a gap with the first stage and a second electrode disposed within the second stage, the first electrode and the second electrode are electrically coupled by an ionic liquid disposed in the gap, and conductive fine particles are mixed in the ionic liquid.

[0083] B Buffer space C Coil G Gap L Ionic liquid R Ring assembly W Substrate 1 Substrate processing device 10 Processing chamber 10a Through hole 10b Through hole 10e Gas outlet 10s Processing space 11 Dielectric window 12 Antenna 13 Central gas injection section 20 Substrate support 21 Electrostatic chuck 21a Ceramic component 21b Electrode 21b1 Inner electrode 21b2 Outer electrode 22 Base 23 Rotating stage 24 Fixed stage 25 Rotating shaft 250 Wiring 26 Insulating component 27 Rotating mechanism 28 Wiring 280 Electrode 29 Wiring 290 Wiring 30 Insulator 30a Recess 40 Gas supply section 50 Power supply 60 Exhaust section 70 Ionic liquid supply section 71 Ionic liquid supply port 72 Ionic liquid outlet 73 Ionic liquid supply source 80 Measurement system 81 Measuring instrument 82 Power supply 83 Electrode 84 Electrostatic chuck 840 Dielectric 841 Electrode pad 842 Electrode pad 2 Control unit

Claims

1. A substrate support comprising a fixed-side member and a movable-side member that moves relative to the fixed-side member, wherein the movable-side member has a first stage having a support surface for supporting a substrate and a first electrode disposed within the first stage, and the fixed-side member has a second stage disposed below the first stage so as to form a gap between itself and the first stage and a second electrode disposed within the second stage, wherein the first electrode and the second electrode are electrically coupled by an ionic liquid disposed in the gap, and conductive fine particles are mixed in the ionic liquid.

2. The substrate support according to claim 1, wherein the movable member rotates about a rotation axis provided on the fixed member.

3. The substrate support according to claim 1 or 2, wherein the conductive fine particles are fine particles composed of stainless steel, titanium, aluminum, nickel, or an alloy thereof.

4. The substrate support according to claim 1, wherein the diameter of the conductive fine particles is in the range of 1 nm to 100 nm.

5. The concentration of the conductive fine particles in the ionic liquid is 10 mmol / dm 3 ~500mmol / dm 3 A substrate support according to claim 1, wherein the concentration is within the range.

6. The substrate support according to claim 1, wherein the temperature of the ionic liquid is within the range of -10°C to 80°C.

7. The substrate support according to claim 1, further comprising: a first pipe connected to the gap and supplying the ionic liquid to the gap; a second pipe connected to the gap and discharging the ionic liquid from the gap; and an ionic liquid supply source for circulating the ionic liquid disposed in the gap via the first pipe and the second pipe.

8. The substrate support according to claim 1, wherein the ionic liquid comprises at least one selected from N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide and 1-ethyl-3-methylimidazolium dicyanamide.

9. A substrate processing apparatus comprising a processing chamber and a substrate support disposed within the processing chamber and supporting a substrate, wherein the substrate support has a fixed side member and a movable side member that moves relative to the fixed side member, the movable side member includes a first stage having a support surface for supporting the substrate and a first electrode disposed within the first stage, the fixed side member includes a second stage disposed below the first stage so as to form a gap with the first stage and a second electrode disposed within the second stage, the first electrode and the second electrode are electrically coupled by an ionic liquid disposed in the gap, and conductive fine particles are mixed in the ionic liquid.

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