Patent Publication Number: US-2021166958-A1

Title: Piping assembly and substrate processing apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2019-215691, filed on Nov. 28, 2019. the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a piping assembly and a substrate processing apparatus. 
     BACKGROUND 
     In a substrate processing apparatus that performs a process such as etching on a substrate using plasma, it is important to manage the temperature of the substrate. The substrate is placed on an electrostatic chuck provided on a lower electrode. The temperature of the lower electrode is controlled by a refrigerant flowing inside the lower electrode, and the temperature of the electrostatic chuck is controlled by a heater provided therein. A heat transfer gas such as a helium gas is supplied between the electrostatic chuck and the substrate. The heat of the lower electrode is transferred to the electrostatic chuck, and the heat of the electrostatic chuck is transferred to the substrate via the heat transfer gas. By controlling the pressure of the heat transfer gas, the amount of heat transfer between the electrostatic chuck and the substrate can be controlled, so that temperature of the substrate can be controlled. The heat transfer gas is supplied through a pipe provided between a grounded enclosure and the lower electrode. 
     By the way, since RF (Radio Frequency) power is supplied to the lower electrode, a potential difference is generated at both ends of the pipe provided between the enclosure and the lower electrode. As a result, in the pipe, electrons emitted from the electrode are accelerated and collide with atoms of the heat transfer gas in the pipe, which may cause discharging (arcing) in the pipe. In order to prevent this, a technique is known in which a passage in the pipe is formed in a spiral shape (see e.g., Patent Document 1 below). As a result, the length of a space within the pipe in an electric field direction can be shortened, so that the acceleration of electrons can be suppressed, which can suppress the occurrence of discharging. 
     PRIOR ART DOCUMENT 
     Patent Document 
     U.S. Pat. No. 8,503,151 
     SUMMARY 
     According to one embodiment of the present disclosure, there is provided a substrate processing apparatus including a conductive enclosure having a gas passage and being grounded; a substrate support disposed in the conductive enclosure and including a conductive member having a gas passage; a power source connected to the conductive member; and a piping assembly disposed between the conductive enclosure and the conductive member, and configured to supply a gas from an outside of the conductive enclosure to the gas passage of the conductive member through the gas passage of the conductive enclosure, the piping assembly including: a hollow tube having an inner sidewall; a core block disposed in the hollow tube and having an outer sidewall fitting the inner sidewall of the hollow tube, the core block having a first dielectric constant; and at least one dielectric member disposed in at least one of the hollow tube and the core block, the at least one dielectric member having a second dielectric constant higher than the first dielectric constant, wherein at least one of the inner sidewall of the hollow tube and the outer sidewall of the core block has at least one spiral groove, the at least one spiral groove defines an internal passage having a first opening and a second opening, the first opening is in fluid communication with the gas passage of the conductive member, and the second opening is in fluid communication with the gas passage of the conductive enclosure. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the present disclosure. 
         FIG. 1  is a schematic cross-sectional view showing an example of a substrate processing apparatus according to an embodiment of the present disclosure. 
         FIG. 2  is an enlarged cross-sectional view showing an example of a connecting portion between a lower electrode and a piping assembly and a connecting portion between the piping assembly and a bottom portion of a processing container. 
         FIG. 3  is a top view showing an example of the piping assembly. 
         FIG. 4  is a perspective cross-sectional view showing an example of the piping assembly. 
         FIG. 5  is an enlarged cross-sectional view showing an example of a connecting portion between the lower electrode and the piping assembly. 
         FIG. 6  is a view showing an example of a simulation result of a distribution of equipotential lines in the vicinity of an opening in a comparative example. 
         FIG. 7  is a view showing an example of a simulation result of a distribution of equipotential lines in the vicinity of an opening according to the present embodiment. 
         FIG. 8  is a cross-sectional view showing an example of the arrangement of a high dielectric constant member. 
         FIG. 9  is a cross-sectional view showing another example of the arrangement of the high dielectric constant member. 
         FIG. 10  is a top view showing another example of the arrangement of the high dielectric constant member. 
         FIG. 11  is a top view showing another example of the arrangement of the high dielectric constant member. 
         FIG. 12  is a cross-sectional view showing another example of the arrangement of the high dielectric constant member. 
         FIG. 13  is a cross-sectional view showing another example of the arrangement of the high dielectric constant member. 
         FIG. 14  is a cross-sectional view showing another example of the arrangement of the high dielectric constant member. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to various embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, systems, and components have not been described in detail so as not to unnecessarily obscure aspects of the various embodiments. 
     Hereinafter, a piping assembly and a substrate processing apparatus according to an embodiment are described in detail based on the drawings. It should be noted that the following embodiment does not limit the disclosed piping assembly and substrate processing apparatus. 
     By the way, in substrate processing using plasma in recent years, a voltage supplied to a lower electrode tends to increase. Therefore, an electric discharge of the heat transfer gas is likely to occur in a piping assembly. When the voltage supplied to the lower electrode increases, it is conceivable to narrow the width of a spiral passage in the piping assembly to further shorten the length of a space in the piping assembly in an electric field direction. 
     However, in a connecting portion between the piping assembly and the lower electrode, there is a portion where the length of the space in the electric field direction becomes longer than the width of the spiral passage. Therefore, the discharge is more likely to occur at the connecting portion between the piping assembly and the lower electrode than at the inside of the piping assembly. In addition, similarly, the discharge is more likely to occur even between the piping assembly and an enclosure than at the inside of the piping assembly. 
     Therefore, the present disclosure provides a technique capable of suppressing generation of the electric discharge at the connecting portion of the piping assembly. 
     [Configuration of Substrate Processing Apparatus  1 ] 
       FIG. 1  is a schematic cross-sectional view showing an example of a substrate processing apparatus  1  according to an embodiment of the present disclosure. In the present embodiment, the substrate processing apparatus  1  is a plasma etching apparatus that includes parallel flat plate electrodes, for example, and performs etching on a substrate W using capacitively-coupled plasma (CCP). The substrate processing apparatus  1  includes an apparatus body  10  and a controller  11 . The apparatus body  10  has a processing container  12  that is made of, for example, a conductive material such as aluminum and has, for example, substantially a hollow cylinder shape. The processing container  12  is an example of a conductive member. An inner wall surface of the processing container  12  is anodized. Further, the processing container  12  is grounded for safety. The processing container  12  is an example of an enclosure. 
     A substantially cylindrical support  14  made of, for example, an insulating material such as quartz is provided on the bottom of the processing container  12 . The support  14  extends from the bottom of the processing container  12  in a vertical direction (for example, in the direction of an upper electrode  30 ) in the processing container  12 . 
     A stage ST, which is a substrate support, is provided inside the processing container  12 . The stage ST is an example of a conductive member. The stage ST is supported by the support  14 . The stage ST holds the substrate W on the upper surface of the stage ST. The stage ST has an electrostatic chuck ESC and a lower electrode LE. The lower electrode LE is made of, for example, a conductive material such as aluminum, and has substantially a disc shape. The electrostatic chuck ESC is disposed on the lower electrode LE. 
     The electrostatic chuck ESC has a structure in which an electrode EL, which is a conductive film, is disposed between a pair of insulating layers or a pair of insulating sheets. A DC power supply  19  is electrically connected to the electrode EL via a switch SW. The electrostatic chuck ESC holds the substrate W on the upper surface of the electrostatic chuck ESC by an electrostatic force such as a Coulomb force generated by a DC voltage supplied from the DC power supply  19 . Thereby, the electrostatic chuck ESC can hold and support the substrate W. 
     A heat transfer gas such as a helium gas is supplied to the electrostatic chuck ESC via a pipe  18  and a piping assembly  20 . The heat transfer gas supplied via the pipe  18  and the piping assembly  20  is supplied between the electrostatic chuck ESC and the substrate W. By adjusting a pressure of the heat transfer gas supplied between the electrostatic chuck ESC and the substrate W, the amount of heat transfer between the electrostatic chuck ESC and the substrate W can be adjusted. 
     In addition, a heater HT, which is a heating element, is provided inside the electrostatic chuck ESC. A heater power source HP is connected to the heater HT. By supplying power from the heater power source HP to the heater HT, the substrate W on the electrostatic chuck ESC can be heated via the electrostatic chuck ESC. The heater HT may be disposed between the electrostatic chuck ESC and the lower electrode LE. 
     An edge ring ER is disposed around the electrostatic chuck ESC so as to surround the edge of the substrate W and the electrostatic chuck ESC. The edge ring ER is sometimes called a focus ring. The edge ring ER can improve the in-plane uniformity of processing on the substrate W. The edge ring ER is made of, for example, a material such as quartz that is appropriately selected depending on the material of a film to be etched. 
     A passage  15  through which an insulating fluid such as Galden® flows is formed inside the lower electrode LE. A chiller unit  17  is connected to the passage  15  via a pipe  16   a,  a pipe  16   b,  a pipe  160   a,  and a pipe  160   b.  The chiller unit  17  controls the temperature of the insulating fluid flowing in the passage  15  of the lower electrode LE. The insulating fluid whose temperature is controlled by the chiller unit  17  is supplied into the passage  15  of the lower electrode LE via the pipe  16   a  and the pipe  160   a.  The insulating fluid flowing in the passage  15  is returned to the chiller unit  17  via the pipe  160   b  and the pipe  16   b.  The temperature of the substrate W placed on the electrostatic chuck ESC is adjusted by the lower electrode LE and the heater HT. 
     A power supply tube  69  for supplying RF power to the lower electrode LE is electrically connected to the lower surface of the lower electrode LE. The power supply tube  69  is made of metal. Although not shown in  FIG. 1 , lifter pins for transferring the substrate W on the electrostatic chuck ESC, a drive mechanism thereof, and the like are disposed in a space between the lower electrode LE and the bottom of the processing container  12 . 
     A first RF power source  64  is connected to the power supply tube  69  via a matching device  68 . The first RF power source  64  is a power source that generates RF power for drawing ions into the substrate W, that is, RF bias power, and generates RF bias power of a frequency of 400 [kHz] to 40.68 [MHz], for example, 13.56 [MHz]. The matching device  68  is a circuit for matching the output impedance of the first RF power source  64  and the input impedance on the load (lower electrode LE) side. The RF bias power generated by the first RF power source  64  is supplied to the lower electrode LE via the matching device  68  and the power supply tube  69 . 
     The upper electrode  30  is provided above the stage ST and at a position opposite to the stage ST. The lower electrode LE and the upper electrode  30  are disposed so as to be substantially parallel to each other. Plasma is generated in a space between the upper electrode  30  and the lower electrode LE, and the generated plasma performs plasma processing such as etching on the substrate W held on the upper surface of the electrostatic chuck ESC. The space between the upper electrode  30  and the lower electrode LE is the processing space PS. 
     The upper electrode  30  is supported on the upper portion of the processing container  12  via an insulating shield member  32  made of, for example, quartz or the like. The upper electrode  30  has an electrode plate  34  and an electrode support  36 . The lower surface of the electrode plate  34  faces the processing space PS. A plurality of gas discharge ports  34   a  is formed in the electrode plate  34 . The electrode plate  34  is made of, for example, a material containing silicon. 
     The electrode support  36  is made of, for example, a conductive material such as aluminum, and supports the electrode plate  34  from above in a detachable manner The electrode support  36  may have a water cooling structure (not shown). A diffusion chamber  36   a  is formed inside the electrode support  36 . A plurality of gas flow ports  36   b  communicating with the gas discharge ports  34   a  of the electrode plate  34  extends downward (toward the stage ST) from the diffusion chamber  36   a.  A gas introducing hole  36   c  for introducing a process gas into the diffusion chamber  36   a  is formed in the electrode support  36 , and a pipe  38  is connected to the gas introducing hole  36   c.    
     A gas source group  40  is connected to the pipe  38  via a valve group  42  and a flow rate controller group  44 . The gas source group  40  has a plurality of gas sources. The valve group  42  includes a plurality of valves, and the flow rate controller group  44  includes a plurality of flow rate controllers such as mass flow controllers. Each of the gas sources in the gas source group  40  is connected to the pipe  38  via a corresponding one in the valve group  42  and a corresponding one in the flow rate controller group  44 . 
     As a result, the apparatus body  10  supplies a gas, which is supplied from one or more gas sources selected from the gas source group  40 , into the diffusion chamber  36   a  in the electrode support  36  at an individually adjusted flow rate. The gas supplied into the diffusion chamber  36   a  diffuses in the diffusion chamber  36   a  and is supplied in a shower shape into the processing space PS via the individual gas flow ports  36   b  and the individual gas discharge ports  34   a.    
     A second RF power supply  62  is connected to the electrode support  36  via a matching device  66 . The second RF power supply  62  is a power supply that generates RF power for plasma generation, and generates RF power having a frequency of 27 [MHz] to 100 [MHz], for example, 60 [MHz]. The matching device  66  is a circuit for matching the output impedance of the second RF power supply  62  and the input impedance of the load (upper electrode  30 ) side. The RF power generated by the second RF power supply  62  is supplied to the upper electrode  30  via the matching device  66 . Further, the second RF power supply  62  may be connected to the lower electrode LE via the matching device  66 . 
     A deposition shield  46 , which is made of aluminum or the like and whose surface is coated with Y 2 O 3 , quartz, or the like, is detachably provided on the inner wall surface of the processing container  12  and the outer surface of the support  14 . The deposition shield  46  can prevent etching by-products (depositions) from adhering to the processing container  12  and the support  14 . 
     An exhaust plate  48 , which is made of aluminum or the like and has a surface coated with Y 2 O 3  or quartz, is provided between the outer sidewall of the support  14  and the inner sidewall of the processing container  12  on the bottom side of the processing container  12  (the side where the support  14  is provided). An exhaust port  12   e  is provided below the exhaust plate  48 . An exhaust device  50  is connected to the exhaust port  12   e  via an exhaust pipe  52 . 
     The exhaust device  50  has a vacuum pump such as a turbo molecular pump, and can reduce an internal pressure of the processing container  12  to a desired degree of vacuum. An opening  12   g  for loading and unloading the substrate W is formed on the sidewall of the processing container  12  and can be opened and closed by a gate valve  54 . 
     The controller  11  has a processor, a memory, and an input/output interface. The memory stores programs executed by the processor, and recipes including conditions for each process. The processor executes the programs read from the memory and controls each part of the apparatus body  10  through the input/output interface based on the recipes stored in the memory to execute a predetermined process such as etching. 
     [Details of Piping Assembly  20 ] 
       FIG. 2  is an enlarged cross-sectional view showing an example of a connecting portion between the lower electrode LE and the piping assembly  20  and a connecting portion between the piping assembly  20  and the bottom of the processing container  12 . The piping assembly  20  is disposed between the lower electrode LE and the bottom of the processing container  12  and allows the heat transfer gas supplied from the outside of the processing container  12  to flow to the lower electrode LE. A space  301  at the connecting portion between the lower electrode LE and the piping assembly  20  is sealed by a sealing member  302  such as an O-ring. The space  301  is in communication with a passage  300  formed in the lower electrode LE. A space  304  at the connecting portion between the bottom of the processing container  12  and the piping assembly  20  is sealed by a sealing member  305  such as an O-ring. The space  304  is in communication with a passage  303  formed at the bottom of the processing container  12 . 
     The piping assembly  20  has a hollow tube  200 , a high dielectric constant member  201 , and a core block  202 . The high dielectric constant member  201  is made of a material having a higher dielectric constant than the hollow tube  200  and the core block  202 . In the present embodiment, the hollow tube  200  and the core block  202  are made of, for example, resin, and the high dielectric constant member  201  is made of, for example, a material containing at least one of quartz, ceramics, silicon, and metals. 
     The core block  202  is accommodated in the hollow tube  200 , and the outer shape of the outer sidewall of the core block  202  has a shape fitting the inner sidewall of the hollow tube  200 . In the present embodiment, the outer shape of the core block  202  is substantially a cylinder shape, and the inner sidewall of the hollow tube  200  is substantially a hollow cylinder shape. Note that the outer sidewall of the core block  202  and the inner sidewall of the hollow tube  200  may have a prismatic shape and a rectangular cylindrical shape as long as they have corresponding shapes. 
     In the present embodiment, a spiral groove  2020  is formed on the outer sidewall of the core block  202  along the outer sidewall of the core block  202 . In a state where the core block  202  is accommodated in the hollow tube  200 , a space formed by the groove  2020  and the inner sidewall of the hollow tube  200  forms a passage through which the heat transfer gas flows. Since the outer shape of the outer sidewall of the core block  202  is substantially a cylinder shape and the inner sidewall of the hollow tube  200  is substantially a hollow cylinder shape, even when the width of the groove  2020  is narrowed, it is possible to suppress a decrease in conductance of the passage formed by the groove  2020  and the inner sidewall of the hollow tube  200 . In addition, the spiral groove  2020  may be formed on the inner sidewall of the hollow tube  200 , or may be formed on both the outer sidewall of the core block  202  and the inner sidewall of the hollow tube  200 . 
     An opening  2021  and an opening  2022  communicating with the groove  2020  are provided at both ends of the core block  202 . The opening  2021  communicates with the passage  300  of the lower electrode LE via the space  301 . The opening  2022  communicates with the passage  303  at the bottom of the processing container  12  via the space  304 . Further, the opening  2021  and the opening  2022  may be provided in the hollow tube  200 . 
       FIG. 3  is a top view showing an example of the piping assembly  20 .  FIG. 4  is a perspective cross-sectional view showing an example of the piping assembly  20 . The heat transfer gas supplied from the passage  303  at the bottom of the processing container  12  via the opening  2022  flows, for example, into a spiral passage formed by the groove  2020  provided on the outer sidewall of the core block  202  and the inner sidewall of the hollow tube  200 , as shown in  FIG. 4 . Then, the heat transfer gas flowing in the spiral passage flows into the passage  300  of the lower electrode LE via the opening  2021  and the space  301 . 
     The high dielectric constant member  201  is provided at the end of the hollow tube  200  and in the vicinity of the opening  2021  and the opening  2022 . Further, the high dielectric constant member  201  is also provided at the end of the core block  202  and in the vicinity of the opening  2021  and the opening  2022 . In the present embodiment, the high dielectric constant member  201  is annularly disposed at the end of the hollow tube  200  along the outer sidewall of the core block  202  so as to surround the opening  2021 . Further, in the present embodiment, the high dielectric constant member  201  is annularly disposed on the side closer to an axis X (a spiral axis formed by the groove  2020 ) of the core block  202  than the opening  2021  along the outer sidewall of the core block  202  so as to surround the axis X. In the present embodiment, the high dielectric constant member  201  has, for example, substantially a hollow cylinder shape as shown in  FIGS. 3 and 4 . 
     Here, RF power is supplied from the first RF power source  64  to the lower electrode LE, and the processing container  12  is grounded. Therefore, a potential difference is generated between the lower electrode LE and the processing container  12 . If the passage of the heat transfer gas in the piping assembly  20  is linear between the bottom of the processing container  12  and the lower electrode LE, a potential difference across the piping assembly  20  causes electrons emitted from the lower electrode LE or the bottom of the processing container  12  to be accelerated in the piping assembly  20 . When the potential difference between the lower electrode LE and the processing container  12  becomes large, the electrons accelerated in the piping assembly  20  collide with atoms of the heat transfer gas in the piping assembly  20 , thereby generating discharge (arcing). 
     In order to prevent the discharge in the piping assembly  20 , it is necessary to shorten the length of the passage in the electric field direction. For example, by making the passage of the heat transfer gas in the piping assembly  20  spiral, it is possible to suppress the discharge of the heat transfer gas in the piping assembly  20 . 
     However, with the recent increase in voltage of a process, the situation is such that the heat transfer gas is likely to be discharged easily in the piping assembly  20 . In particular, in the connecting portion between the piping assembly  20  and the lower electrode LE and the connecting portion between the piping assembly  20  and the bottom of the processing container  12 , since the length of the space in the electric field direction becomes longer than the width of the spiral passage, the situation is such that the discharge is likely to occur easily at the connecting portions. 
       FIG. 5  is an enlarged cross-sectional view showing an example of the connecting portion between the lower electrode LE and the piping assembly  20 . Although the connection portion between the piping assembly  20  and the lower electrode LE will be described below, the same applies to the connection portion between the piping assembly  20  and the bottom of the processing container  12 . 
     The width ΔW 3  of the opening  2021 , which is the outlet of the passage formed by the spiral groove  2020 , is wider than the width ΔW 1  of the spiral groove  2020  and the width ΔW 2  of the space  301  of the connecting portion between the lower electrode LE and the piping assembly  20 , as shown, for example, in  FIG. 5 . Therefore, the discharge is more likely to occur in the opening  2021  than in the groove  2020  and the space  301 . In order to prevent this, in the present embodiment, as shown, for example, in  FIGS. 2 to 4 , a high dielectric constant member  201  formed of a material having a higher dielectric constant than the hollow tube  200  and the core block  202  is disposed in the vicinity of the opening  2021 . 
     Here, a distribution of equipotential lines in the vicinity of the opening  2021  is calculated by simulation.  FIG. 6  is a view showing an example of a simulation result of a distribution of equipotential lines in the vicinity of the opening  2021  in a comparative example.  FIG. 7  is a view showing an example of a simulation result of a distribution of equipotential lines in the vicinity of the opening  2021  in the present embodiment. In case of the comparative example in which the high dielectric constant member  201  is not disposed in the vicinity of the opening  2021 , the density of equipotential lines in the vicinity of the opening  2021  is high, as indicated, for example, by a broken line in  FIG. 6 . Therefore, the discharge is likely to occur in the vicinity of the opening  2021 . 
     In contrast, in the present embodiment, since the high dielectric constant member  201  is disposed in the vicinity of the opening  2021 , the density of equipotential lines in the vicinity of the opening  2021  is low, as indicated, for example, by a broken line in  FIG. 7 . As a result, the discharge in the vicinity of the opening  2021  can be suppressed. 
     Similarly, in the connecting portion between the piping assembly  20  and the bottom of the processing container  12 , since the high dielectric constant member  201  is disposed in the vicinity of the opening  2022 , the density of equipotential lines in the vicinity of the opening  2022  is low, and as a result, the discharge in the vicinity of the opening  2022  can be suppressed. 
     In addition, the high dielectric constant member  201  is disposed, for example, at a position shown in  FIG. 8  with respect to the opening  2021 .  FIG. 8  is a cross-sectional view showing an example of the arrangement of the high dielectric constant member  201 . The high dielectric constant member  201  is disposed at a position at a distance ΔL 1  from the opening  2021 . In the present embodiment, the distance ΔL 1  may be, for example, within twice the width ΔW 1  of the groove  2020 . The length ΔL 2  of the high dielectric constant member  201  in a direction along the axis X of the piping assembly  20  may be, for example, 12 times or more the width ΔW 1  of the groove  2020 . In addition, the width ΔW 4  of the high dielectric constant member  201  may be, for example, three times or more the width ΔW 1  of the groove  2020 . 
     In addition, the smaller the distance ΔL 1  is, the shorter the length ΔL 2  may be, and the larger the distance ΔL 1  is, the longer the length ΔL 2  may be. 
     The embodiment has been described above. As described above, the piping assembly  20  according to the present embodiment is a piping assembly  20  that is disposed between the lower electrode LE and the bottom of the processing container  12  with a potential difference therebetween and flows a gas from the bottom of the processing container  12  to the lower electrode LE, and includes the hollow tube  200 , the high dielectric constant member  201 , and the core block  202 . The core block  202  is disposed in the hollow tube  200  and has an outer sidewall having a shape corresponding to the inner sidewall of the hollow tube  200 . The high dielectric constant member  201  has a higher dielectric constant than the hollow tube  200  and the core block  202 . The spiral groove  2020  is formed on at least one of the inner sidewall of the hollow tube  200  and the outer sidewall of the core block  202 . The spiral groove  2020  forms the gas passage in a state in which the core block  202  is accommodated in the hollow tube  200 . The high dielectric constant member  201  is disposed at one or both of the end of the hollow tube  200  and the end of the core block  202 . As a result, it is possible to suppress the occurrence of discharge in the connecting portions of the piping assembly  20 . 
     In addition, in the above embodiment, the inner sidewall of the hollow tube  200  has a hollow cylinder shape, and the outer shape of the outer sidewall of the core block  202  is a cylinder shape. As a result, it is possible to suppress a decrease in conductance of the passage formed by the groove  2020  and the inner sidewall of the hollow tube  200 . 
     In addition, in the above embodiment, the high dielectric constant member  201  is annularly disposed at the end of the hollow tube  200  along the outer sidewall of the core block  202 . As a result, it is possible to suppress the occurrence of discharge in the connecting portions of the piping assembly  20 . 
     In addition, in the above embodiment, the high dielectric constant member  201  is annularly disposed along the outer sidewall of the core block  202  so as to surround the axis of the core block  202 . As a result, it is possible to suppress the occurrence of discharge in the connecting portions of the piping assembly  20 . 
     In addition, in the above embodiment, the distance ΔL 1  between the groove  2020  and the high dielectric constant member  201  is within twice the width ΔW 1  of the groove  2020 . Further, the length ΔL 2  of the high dielectric constant member  201  in the direction along the axis X is 12 times or more the width ΔW 1  of the groove  2020 . As a result, it is possible to suppress the occurrence of discharge in the connecting portions of the piping assembly  20 . 
     Additionally, in the above embodiment, the hollow tube  200  and the core block  202  are made of, for example, resin, and the high dielectric constant member  201  is made of, for example, a material containing at least one of quartz, ceramics, silicon, and metals. As a result, it is possible to suppress the occurrence of discharge in the connecting portions of the piping assembly  20 . 
     Further, the substrate processing apparatus  1  in the above embodiment includes the processing container  12  which is grounded, the stage ST which is provided in the processing container  12  and applied with a predetermined voltage is applied and on which the substrate W is placed, and the piping assembly  20  which is provided between the processing container  12  and the stage ST and supplies a gas from the outside of the processing container  12  to the stage ST via the processing container  12 . The piping assembly  20  includes the hollow tube  200 , the high dielectric constant member  201 , and the core block  202 . The core block  202  is disposed in the hollow tube  200  and has an outer sidewall having a shape corresponding to the inner sidewall of the hollow tube  200 . The high dielectric constant member  201  has a higher dielectric constant than the hollow tube  200  and the core block  202 . The spiral groove  2020  is formed on at least one of the inner sidewall of the hollow tube  200  and the outer sidewall of the core block  202 . The spiral groove  2020  forms a gas passage in a state where the core block  202  is accommodated in the hollow tube  200 . The high dielectric constant member  201  is disposed at one or both of the end of the hollow tube  200  and the end of the core block  202 . As a result, it is possible to suppress the occurrence of discharge in the connecting portions of the piping assembly  20 . 
     [Others] 
     The technique disclosed in the present disclosure is not limited to the above embodiment, but various modifications can be made within the scope of the disclosure. 
     For example, in the above embodiment, the high dielectric constant member  201  is provided at both the end of the hollow tube  200  and the end of the core block  202 , but the disclosed technique is not limited thereto. For example, the high dielectric constant member  201  may be provided at only one of the end of the hollow tube  200  and the end of the core block  202 . When provided at the end of the core block  202 , the high dielectric constant member  201  may be formed in substantially a cylinder shape, as shown, for example, in  FIG. 9 .  FIG. 9  is a cross-sectional view showing another example of the arrangement of the high dielectric constant members  201 . 
     In addition, in the above embodiment, the shape of the high dielectric constant member  201  is a hollow cylinder shape (see  FIG. 4 ), but the disclosed technique is not limited thereto. If the high dielectric constant member  201  is annularly disposed at the end of the hollow tube  200  along the outer sidewall of the core block  202  so as to surround the opening  2021 , it may be divided into a plurality of high dielectric constant members  201 , as shown, for example, in  FIG. 10 . In addition, if the high dielectric constant member  201  is annularly disposed on the core block  202  on the axis X side from the opening  2021  along the outer sidewall of the core block  202  so as to surround the axis X, it may be divided into a plurality of high dielectric constant members  201 , as shown, for example, in  FIG. 10 .  FIG. 10  is a top view showing another example of the arrangement of the high dielectric constant members  201 . 
     In addition, as shown, for example, in  FIG. 11 , a plurality of high dielectric constant members  201  may be disposed along the outer sidewall of the core block  202  at the end of the hollow tube  200  so as to surround the opening  2021 , and may be annularly disposed on the core block  202  on the axis X side of the opening  2021  so as to surround the axis X.  FIG. 11  is a top view showing another example of the arrangement of the high dielectric constant member  201 . In the example of  FIG. 11 , each high dielectric constant member  201  is formed in a rod shape and is disposed at the ends of the hollow tube  200  and the core block  202  so that the longitudinal direction of each high dielectric constant member  201  is oriented along the direction of the axis X. 
     In addition, in the above embodiment, each high dielectric constant member  201  is not in contact with the lower electrode LE and the bottom of the processing container  12 , but the disclosed technique is not limited thereto. As another configuration, each high dielectric constant member  201  may be in contact with the lower electrode LE or the bottom of the processing container  12 , as shown, for example, in  FIG. 12 .  FIG. 12  is a cross-sectional view showing another example of the arrangement of the high dielectric constant member  201 . In the example of  FIG. 12 , each high dielectric constant member  201  is biased by a biasing member  2010  toward the lower electrode LE or toward the bottom of the processing container  12 . The biasing member  2010  is an elastic body such as an O-ring, a metal spiral, a spring, or the like. As a result, the magnitude of an electric field between the lower electrode LE and the high dielectric constant member  201  and between the bottom of the processing container  12  and the high dielectric constant member  201  can be reduced, thereby further suppressing the discharge at the connecting portions of the piping assembly  20 . 
     In addition, in the configuration illustrated in  FIG. 12 , the shape of each high dielectric constant member  201  may be the same as that of the high dielectric constant member  201  illustrated, for example, in  FIG. 10 or 11 . In addition, when the shape of each high dielectric constant member  201  is a hollow cylinder shape, the high dielectric constant member  201  may not be provided at the end of the core block  202 . 
     In addition, in the above embodiment, each high dielectric constant member  201  is provided at the ends of the hollow tube  200  and the core block  202 , but the disclosed technique is not limited thereto. For example, as shown in  FIG. 13 , a concave portion  2011  having a shape corresponding to the high dielectric constant member  201  may be formed at the ends of the hollow tube  200  and the core block  202 , and the high dielectric constant member  201  may be provided at positions of the lower electrode LE and the bottom of the processing container  12 , which face the concave portion  2011 .  FIG. 13  is a cross-sectional view showing another example of the arrangement of the high dielectric constant member  201 . Even with such a configuration, it is possible to suppress the occurrence of discharge at the connecting portions of the piping assembly  20 . 
     Further, the concave portion  2011  formed at the ends of the hollow tube  200  and the core block  202  and the high dielectric constant member  201  provided on the lower electrode LE act as a guide to assist alignment when the piping assembly  20  is attached to the lower electrode LE. Similarly, the concave portion  2011  formed at the ends of the hollow tube  200  and the core block  202  and the high dielectric constant member  201  provided at the bottom of the processing container  12  act as a guide to assist alignment when the piping assembly  20  is attached to the bottom of the processing container  12 . As a result, the assembly of the apparatus body  10  can be facilitated. 
     In addition, in  FIG. 13 , the high dielectric constant member  201  is provided at the ends of the hollow tube  200  and the core block  202 , but the disclosed technique is not limited thereto. For example, a concave portion  2011  having a shape corresponding to the high dielectric constant member  201  may be formed at the ends of the hollow tube  200  and the core block  202 , and a concave portion having a shape corresponding to the high dielectric constant member  201  may also be formed at positions of the lower electrode LE and the bottom of the processing container  12 , which face the concave portion  2011 . In this case, for example, after the high dielectric constant member  201  is inserted into the concave portion  2011  at the ends of the hollow tube  200  and the core block  202  or the concave portion at the lower electrode LE and the bottom of the processing container  12 , the piping assembly  20  is assembled to the bottom of the processing container  12  and the lower electrode LE. 
     Additionally, as shown, for example, in  FIG. 14 , a convex portion  2013  may be formed on the lower surface of the lower electrode LE at a position facing the concave portion  2011 , and the piping assembly  20  may be attached to the lower electrode LE so that the convex portion  2013  is accommodated in the concave portion  2011 . Further, as shown, for example, in  FIG. 14 , a convex portion  2014  may be formed on the upper surface of the bottom of the processing container  12  at a position facing the concave portion  2011 , and the piping assembly  20  may be attached to the bottom of the processing container  12  so that the convex portion  2014  is accommodated in the concave portion  2011 .  FIG. 14  is a cross-sectional view showing another example of the arrangement of the high dielectric constant member. The convex portion  2013  is formed integrally with the lower electrode LE by the same material as the lower electrode LE, and the convex portion  2014  is formed integrally with the processing container  12  by the same material as the processing container  12 . In the present embodiment, the lower electrode LE and the processing container  12  are made of, for example, a conductive material such as aluminum, and the hollow tube  200  and the core block  202  are made of, for example, resin. Therefore, the convex portion  2013  and the convex portion  2014  have a higher dielectric constant than the hollow tube  200  and the core block  202 . The convex portion  2013  and the convex portion  2014  are examples of the high dielectric constant member. 
     Further, in the above embodiment, the high dielectric constant member  201  made of the same material is provided at the ends of the hollow tube  200  and the core block  202 , but the disclosed technique is not limited thereto. For example, the high dielectric constant member  201  provided at the end of the hollow tube  200  and the high dielectric constant member  201  provided at the end of the core block  202  may be made of different materials. 
     In addition, in the above embodiment, the capacitively-coupled plasma has been described as an example of the plasma source used in the apparatus body  10 , but the plasma source is not limited thereto. Plasma sources other than capacitively-coupled plasma include, for example, inductively-coupled plasma (ICP), microwave excited surface wave plasma (SWP), electron cyclotron resonance plasma (ECP), helicon wave excited plasma (HWP), and the like. 
     Further, in the above embodiment, as the apparatus body  10 , an example of an apparatus that performs etching on the substrate W using plasma has been described, but the disclosed technique is not limited thereto. For example, the disclosed technique can be applied to an apparatus that performs processes such as film formation, modification, or the like using plasma. In addition, the disclosed technique can be applied to an apparatus that does not use plasma but has a pipe that is disposed between two conductive members having a potential difference and flows a gas from one conductive member to the other conductive member. 
     According to the present disclosure in some embodiments, it is possible to suppress the occurrence of discharge at the connecting portions of the pipe. 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosures. Indeed, the embodiments described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the disclosures. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosures.