JP2019164896A - Antenna and plasma processing apparatus - Google Patents

Abstract

To make it possible to secure sealing performance between a conductor element and a hollow insulator even when an antenna is lengthened.SOLUTION: An antenna 3 for generating plasma by causing a high-frequency current to flow, includes: a hollow insulator 32, provided between at least a pair of cylindrical conductor elements 31 and conductor elements 31 adjacent to each other, communicating with an internal space of the conductor elements 31; and a metal seal S respectively provided between the pair of conductor elements 31 and the hollow insulator 32.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an antenna for generating an inductively coupled plasma through a high-frequency current and a plasma processing apparatus including the antenna.

  2. Description of the Related Art Conventionally, a plasma processing apparatus has been proposed in which a high frequency current is passed through an antenna, an inductively coupled plasma (abbreviated as ICP) is generated by an induced electric field generated thereby, and a substrate is processed using the inductively coupled plasma. .

  In this type of plasma processing apparatus, when the antenna is lengthened to cope with a large substrate, the impedance of the antenna increases, thereby generating a large potential difference between both ends of the antenna. As a result, there is a problem that plasma uniformity such as plasma density distribution, potential distribution, and electron temperature distribution is deteriorated due to the influence of the large potential difference, and the uniformity of substrate processing is also deteriorated. In addition, when the impedance of the antenna increases, there is a problem that it is difficult for a high-frequency current to flow through the antenna.

  In order to solve such a problem, as shown in Patent Document 1, a plurality of metal pipes are connected with a hollow insulator interposed between adjacent metal pipes, and are connected to the outer periphery of the hollow insulator. A device in which a capacitor, which is a capacitive element, is arranged. Specifically, the metal pipe and the hollow insulator are screwed together, and in order to ensure a sealing property between them, a rubber O is provided between the outer peripheral surface of the metal pipe and the inner peripheral surface of the hollow insulator. A ring is interposed. Then, by connecting metal pipes screwed to both sides of the hollow insulator electrically in series with the above-described capacitive element, the combined reactance of the antenna can be simply subtracted from the inductive reactance. It will be. As a result, the impedance of the antenna can be reduced, and even when the antenna is lengthened, the increase in impedance is suppressed, high-frequency current can easily flow through the antenna, and plasma with good uniformity can be generated efficiently.

JP-A-2006-138598

  However, with the above-described configuration, the elastic force of the O-ring is lowered due to aging deterioration or thermal influence, and it is difficult to ensure the sealing performance for a long period.

  Therefore, the present invention has been made to solve the above-mentioned problems, and the main object is to ensure the sealing performance between the conductor element and the hollow insulator even when the antenna is lengthened. It is.

  That is, the antenna according to the present invention is an antenna for generating plasma by flowing a high-frequency current, and is provided between at least a pair of cylindrical conductor elements and the conductor elements adjacent to each other. A hollow insulator communicating with the internal space of the conductor element, and a metal seal provided between the pair of conductor elements and the hollow insulator, respectively.

  In the case of an antenna configured in this way, a metal seal that is more resistant to aging and thermal effects than a rubber O-ring is provided between the pair of conductor elements and the hollow insulator, so the antenna is lengthened. Even in this case, the sealing performance between the conductor element and the hollow insulator can be ensured.

If the hollow insulator is made of a material having a strength lower than that of a metal seal such as a resin, the hollow insulator is deformed even if the metal seal is crushed, resulting in poor sealing performance.
Therefore, it is preferable that a receiving member provided at both ends of the hollow insulator to be hit by the metal seal is further provided, and the receiving member is made of a material stronger than the hollow insulator.
With such a configuration, since the receiving member made of a material stronger than the hollow insulator receives the metal seal, the metal seal can be reliably crushed while suppressing deformation of the hollow insulator.

A capacitor element electrically connected in series with the pair of conductor elements, the capacitor element being electrically connected to one of the pair of conductor elements and passing through the interior of the hollow insulator; A first electrode extending to the other side of the pair of conductor elements, and electrically connected to the other of the pair of conductor elements and passing through the hollow insulator to one side of the pair of conductor elements A second electrode facing the first electrode, the first electrode being provided on one of the receiving members, and the second electrode being the other receiving member Is preferably provided.
In such a configuration, since the capacitive element is electrically connected in series with the pair of conductor elements, as described above, the combined reactance of the antenna is obtained by subtracting the capacitive reactance from the inductive reactance. be able to. As a result, the impedance of the antenna can be reduced, and even when the antenna is lengthened, the increase in impedance is suppressed, high-frequency current can easily flow through the antenna, and plasma with good uniformity can be generated efficiently.
In addition, since each of the first electrode and the second electrode is provided on the receiving member, if the receiving member is attached to the hollow insulator, the first electrode and the second electrode can be opposed to each other. An element can be formed easily.

When the receiving member is detachably provided on the hollow insulator, the relative positional relationship between the first electrode and the second electrode can change each time the receiving member is attached to the hollow insulator. The reproducibility of the capacitance is poor.
Therefore, it is preferable that the receiving member is welded to the hollow insulator.
In this case, since the receiving member and the hollow insulator are integrated, the reproducibility of the capacitance is not deteriorated. Moreover, since the receiving member and the hollow insulator are welded, it is not necessary to provide a seal between them, and the number of parts can be reduced.

As a specific configuration of the metal seal, a first ferrule that hits the receiving member, a second ferrule disposed closer to the conductor element than the first ferrule, and the second ferrule along the axial direction It is preferable to have a pushing member that is pushed into the first ferrule side and screwed into the receiving member.
With such a configuration, the seal between the receiving member and the first ferrule can be face-sealed. For example, the sealing performance is higher than that of a shaft seal using a metal gasket or a metal O-ring as a metal seal. Is good.

It is preferable that the dielectric of the capacitive element is a liquid that fills a space between the first electrode and the second electrode.
With such a configuration, since the space between the first electrode and the second electrode is filled with the liquid dielectric, it is possible to eliminate a gap generated between the electrode and the dielectric constituting the capacitive element. it can. As a result, arc discharge that can occur in the gap between the electrode and the dielectric can be eliminated, and damage to the capacitive element due to arc discharge can be eliminated. In addition, the capacitance value can be accurately set from the distance between the first electrode and the second electrode, the facing area, and the relative dielectric constant of the liquid dielectric without considering the gap. Furthermore, the structure for pressing the electrode and the dielectric for filling the gap can be eliminated, and the structure around the antenna due to the pressing structure can be prevented from being complicated and the uniformity of plasma caused thereby can be prevented.

It is preferable that the dielectric is a coolant that flows inside the pair of conductor elements.
With such a configuration, the antenna that tends to become high temperature due to heat generated at the time of plasma generation can be cooled by the coolant, so that damage to the antenna itself or damage to the surrounding structure can be prevented and stable. Plasma can be generated.
In addition, since the cooling liquid is used as the dielectric of the capacitive element, it is possible to suppress unexpected fluctuations in the capacitance while cooling the capacitive element.
Furthermore, by using the cooling liquid as a dielectric while adjusting the temperature to a constant temperature by a temperature control mechanism, it is possible to suppress changes in the relative permittivity due to temperature changes, and it is possible to suppress changes in capacitance that occur accordingly. .

A plasma processing apparatus according to the present invention includes the antenna described above, a vacuum container in which the antenna is disposed inside or outside, and a high-frequency power source that applies a high-frequency current to the antenna. It is.
If it is the plasma processing apparatus comprised in this way, the effect similar to the antenna mentioned above can be acquired.

  According to the present invention configured as described above, even when the antenna is lengthened, the sealing performance between the conductor element and the hollow insulator can be ensured.

It is a longitudinal cross-sectional view which shows typically the structure of the plasma processing apparatus of this embodiment. FIG. 3 is an enlarged cross-sectional view schematically showing a peripheral configuration of the antenna of the same embodiment. It is a schematic diagram which shows the structure of the metal seal of the embodiment. It is a schematic diagram which shows the structure of the metal seal of deformation | transformation embodiment. It is a schematic diagram which shows the structure of the metal seal of deformation | transformation embodiment. It is a longitudinal cross-sectional view which shows typically the structure of the plasma processing apparatus of deformation | transformation embodiment.

  Hereinafter, an embodiment of a plasma processing apparatus according to the present invention will be described with reference to the drawings.

<Device configuration>
The plasma processing apparatus 100 of this embodiment performs processing on the substrate W using inductively coupled plasma P. The substrate W is, for example, a substrate for a flat panel display (FPD) such as a liquid crystal display or an organic EL display, a flexible substrate for a flexible display, or the like. The processing applied to the substrate W is, for example, film formation by plasma CVD, etching, ashing, sputtering, or the like.

  The plasma processing apparatus 100 is a plasma CVD apparatus when a film is formed by plasma CVD, a plasma etching apparatus when etching is performed, a plasma ashing apparatus when ashing is performed, and a plasma sputtering apparatus when sputtering is performed. be called.

  Specifically, as shown in FIG. 1, the plasma processing apparatus 100 includes a vacuum vessel 2 that is evacuated and into which a gas 7 is introduced, a linear antenna 3 that is disposed in the vacuum vessel 2, and a vacuum vessel 2. And a high frequency power source 4 for applying a high frequency for generating the inductively coupled plasma P to the antenna 3. When a high frequency is applied to the antenna 3 from the high frequency power source 4, a high frequency current IR flows through the antenna 3, an induction electric field is generated in the vacuum chamber 2, and inductively coupled plasma P is generated.

  The vacuum vessel 2 is, for example, a metal vessel, and the inside thereof is evacuated by the evacuation device 6. The vacuum vessel 2 is electrically grounded in this example.

The gas 7 is introduced into the vacuum vessel 2 via, for example, a flow rate regulator (not shown) and a plurality of gas inlets 21 formed on the side wall of the vacuum vessel 2. The gas 7 may be made in accordance with the processing content applied to the substrate W. For example, when forming a film on the substrate W by the plasma CVD method, the gas 7 is a source gas or a gas obtained by diluting it with a diluent gas (for example, H ₂ ). More specifically, when the source gas is SiH ₄ , the Si film is formed, when SiH ₄ + NH ₃ is used, the SiN film is formed, when SiH ₄ + O ₂ is used, the SiO ₂ film is formed, and when SiF ₄ + N ₂ is used, the SiN film is formed. : F films (fluorinated silicon nitride films) can be formed on the substrate W, respectively.

  A substrate holder 8 that holds the substrate W is provided in the vacuum container 2. As in this example, a bias voltage may be applied to the substrate holder 8 from the bias power supply 9. The bias voltage is, for example, a negative DC voltage, a negative pulse voltage, or the like, but is not limited thereto. With such a bias voltage, for example, the energy when positive ions in the plasma P are incident on the substrate W can be controlled to control the crystallinity of the film formed on the surface of the substrate W. . A heater 81 for heating the substrate W may be provided in the substrate holder 8.

  The antenna 3 is disposed above the substrate W in the vacuum container 2 so as to be along the surface of the substrate W (for example, substantially parallel to the surface of the substrate W). The number of antennas 3 arranged in the vacuum vessel 2 may be one or plural.

  Near both ends of the antenna 3, the opposite side walls of the vacuum container 2 are respectively penetrated. Insulating members 11 are respectively provided at portions where both ends of the antenna 3 penetrate outside the vacuum vessel 2. Both end portions of the antenna 3 pass through the insulating members 11, and the through portions are vacuum-sealed by, for example, packing 12. Each insulating member 11 and the vacuum vessel 2 are also vacuum-sealed by, for example, packing 13. The material of the insulating member 11 is, for example, ceramics such as alumina, quartz, or engineering plastic such as polyphenylene sulfide (PPS) or polyether ether ketone (PEEK).

  Further, a portion of the antenna 3 located in the vacuum vessel 2 is covered with a straight tubular insulating cover 10. Both ends of the insulating cover 10 are supported by insulating members 11. In addition, it is not necessary to seal between the both ends of the insulating cover 10 and the insulating member 11. This is because even if the gas 7 enters the space in the insulating cover 10, the space P is small and the electron moving distance is short, so that plasma P is not normally generated in the space. The material of the insulating cover 10 is, for example, quartz, alumina, fluororesin, silicon nitride, silicon carbide, silicon or the like.

  By providing the insulating cover 10, it is possible to prevent charged particles in the plasma P from entering the metal pipe 31 constituting the antenna 3, so that charged particles (mainly electrons) enter the metal pipe 31. An increase in plasma potential can be suppressed, and metal contamination (metal contamination) on the plasma P and the substrate W caused by sputtering of the metal pipe 31 by charged particles (mainly ions) can be suppressed. .

  A high-frequency power source 4 is connected to a feeding end portion 3a that is one end portion of the antenna 3 via a matching circuit 41, and a termination portion 3b that is the other end portion is directly grounded. The power supply end 3a may be connected to the high-frequency power source 4 via a capacitor or a coil, and the terminal end 3b may be grounded via a capacitor or a coil.

  With the above configuration, the high-frequency current IR can flow from the high-frequency power source 4 to the antenna 3 through the matching circuit 41. The frequency of the high-frequency current IR is, for example, a general 13.56 MHz, but is not limited thereto.

  The antenna 3 has a hollow structure having a flow path through which the coolant CL flows. The coolant CL circulates through the antenna 3 through a circulation channel 14 provided outside the vacuum vessel 2, and the circulation channel 14 has heat for adjusting the coolant CL to a constant temperature. A temperature control mechanism 141 such as an exchanger and a circulation mechanism 142 such as a pump for circulating the coolant CL in the circulation flow path 14 are provided. As the cooling liquid CL, high resistance water is preferable from the viewpoint of electrical insulation, for example, pure water or water close thereto is preferable. In addition, a liquid refrigerant other than water, such as a fluorine-based inert liquid, may be used.

  Specifically, as shown in FIG. 2, the antenna 3 is provided between at least a pair of tubular metal conductor elements 31 (hereinafter referred to as “metal pipes 31”) and metal pipes 31 adjacent to each other. In addition, a tubular hollow insulator 32 (hereinafter referred to as “insulating pipe 32”) that insulates the metal pipes 31 is provided.

  In the present embodiment, the number of metal pipes 31 is two, and the number of insulating pipes 32 is one. In the following description, one metal pipe 31 is also referred to as “first metal pipe 31A”, and the other metal pipe is also referred to as “second metal pipe 31B”. The antenna 3 may have a configuration including three or more metal pipes 31. In this case, the number of insulating pipes 32 is one less than the number of metal pipes 31.

  The metal pipe 31 has a straight tube shape in which a linear flow path 31x in which the cooling liquid CL flows is formed, and the material is, for example, copper, aluminum, an alloy thereof, stainless steel, or the like.

  The insulating pipe 32 has a straight tube shape in which a linear flow path 32x in which the cooling liquid CL flows is formed. Although the insulating pipe 32 of this embodiment is formed from a single member, it may be formed by joining a plurality of members. The insulating pipe 32 is made of, for example, alumina, fluororesin, polyethylene (PE), engineering plastic (for example, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), etc.).

  As shown in FIGS. 2 and 3, the antenna 3 according to the present embodiment is provided between the first metal pipe 31 </ b> A and the insulating pipe 32 and between the second metal pipe 31 </ b> B and the insulating pipe 32. The metal seal S provided in the is provided.

  More specifically, the metal seal S is for ensuring the sealing performance between the metal pipes 31A and 31B and the insulating pipe 32, and here, the receivers provided at both ends of the insulating pipe 32 are used. By being pressed against the member Z, at least a part is configured to be pressed and deformed.

First, the receiving member Z will be described.
The receiving member Z is for preventing the insulating pipe 32 from being deformed when the metal seal S is pressed and deformed, and is made of a material stronger than the insulating pipe 32, such as aluminum, copper, and the like. It is formed from a metal such as an alloy.

  As shown in FIG. 2, the receiving member Z communicates with the insulating pipe 32, and one end Z1 is fitted into a countersink 321 that is countersunk the inner wall of the insulating pipe 32, and the other end Z2 is fitted. The end 31t of the metal pipe 31 is inserted. Here, the outer diameter of the end portion 31t of the metal pipe 31 is smaller than the outer diameter of the central portion of the metal pipe 31, and the inner diameter of the receiving member Z is substantially the same as the outer diameter of the end portion 31t of the metal pipe 31. Slightly larger.

A contact surface Za on which the end 31t of the metal pipe 31 inserted from the other end Z2 abuts is formed at one end Z1 of the receiving member Z.
The contact surface Za is a surface with which the end surface of the metal pipe 31 contacts, and the receiving member Z and the metal pipe 31 are electrically connected by the contact of the end surface of the metal pipe 31 with the contact surface Za. .

A first pressed surface X1 to which the metal seal S is pressed is formed on the other end Z2 of the receiving member Z.
The first pressed surface X1 is formed on the inner peripheral surface of the other end Z2 of the receiving member Z, and has a truncated cone-shaped slope that gradually increases in diameter from the one end Z1 side toward the other end Z2 side. It is a plane and is inclined with respect to the axial direction of the antenna 3. Moreover, the external thread part N1 is formed in the outer peripheral surface of the other end part Z2, and it is comprised so that the pushing member S3 which is the component of the metal seal S mentioned later may be screwed together.

  In the receiving member Z, a large-diameter portion Z3 having an outer diameter larger than that of the insulating pipe 32 is provided between the one end portion Z1 and the other end portion Z2. The large-diameter portion Z3 is brought into contact with the end face of the insulating pipe 32 and the contact portion is welded so that the receiving member Z and the insulating pipe 32 are integrally provided so as not to be separated.

Next, the metal seal S will be described.
As shown in FIG. 3, the metal seal S is a so-called double ferrule that is interposed between the receiving member Z and the metal pipe 31. Specifically, the metal seal S includes a first ferrule S1 pressed against the receiving member Z, a second ferrule S2 positioned closer to the metal pipe 31 than the first ferrule S1, and a second ferrule S2 on the metal pipe 31 side. And a pushing member S3 that pushes toward the first ferrule S1. The first ferrule S1, the second ferrule S2, and the pushing member S3 form a ring shape that is fitted on the end 31t of the metal pipe 31, and here, the same material as the metal pipe 31, that is, copper, aluminum, Although formed from these alloys, stainless steel, or the like, it may be formed from a material different from the metal pipe 31.

  The first ferrule S1 has an inner diameter that is substantially the same as or slightly larger than the outer diameter of the end 31t of the metal pipe 31, the rear end S1b is pushed by the second ferrule S2, and the front end S1a is attached to the receiving member Z. It will be pushed in. The outer peripheral surface of the first ferrule S1 is a truncated conical inclined surface that gradually increases in diameter from the front end S1a toward the rear end S1b. And the front-end | tip part S1a side of this outer peripheral surface is formed as 1st press surface Y1 pressed against the 1st to-be-pressed surface X1 mentioned above, and is inclined with respect to the axial direction of the antenna 3. FIG. Moreover, the 2nd to-be-pressed surface X2 with which front-end | tip part S2a of 2nd ferrule S2 is pressed is formed in rear-end part S1b of 1st ferrule S1. The second pressed surface X2 is formed, for example, by cutting out the rear end portion S1b of the first ferrule S1, and here is set to the inner peripheral surface of the rear end portion S1b. The second pressed surface X <b> 2 here is an inclined surface that gradually increases in diameter toward the rear, and is inclined with respect to the axial direction of the antenna 3.

  The second ferrule S2 has a front inner peripheral surface S21 having an inner diameter that is substantially the same as or slightly larger than the outer diameter of the end 31t of the metal pipe 31, and a rear inner portion that gradually expands from the front inner peripheral surface S21 toward the rear. It has a peripheral surface S22, the rear end S2b is pushed by the pushing member S3, and the front end S2a is pushed into the rear end S1b of the first ferrule S1. A second pressing surface Y2 that is pressed against the above-described second pressed surface X2 is formed at the tip portion S2a of the second ferrule S2. The second pressing surface Y2 is, for example, an inclined surface that gradually increases in diameter from the front end S2a toward the rear, and is inclined with respect to the axial direction of the antenna 3. The rear end S2b of the second ferrule S2 is formed with a third pressed surface X3 that is pressed by the pressing member S3 and an annular protruding portion S23 that protrudes radially inward from the rear inner peripheral surface S22. ing. The third pressed surface X <b> 3 is an inclined surface that gradually decreases in diameter toward the rear, and is inclined with respect to the axial direction of the antenna 3. By tilting the third pressed surface X3 in this way, when the pressing member S3 presses the second ferrule S2 toward the first ferrule S1, a force that presses the second ferrule S2 radially inward is generated. . As a result, the annular protrusion S <b> 23 is pressed and deformed so as to shrink toward the outer peripheral surface of the metal pipe 31, and the second ferrule S <b> 2 is fixed to the metal pipe 31.

  The pushing member S3 has a front inner peripheral surface S31 formed with a female screw portion N2 that is screwed into the male screw portion N1 formed on the outer peripheral surface of the receiving member Z, and an outer diameter of the end portion 31t of the metal pipe 31. A rear inner peripheral surface S32 having the same or slightly larger inner diameter. On the inner peripheral surface of the pushing member S3, a third pressing surface Y3 that presses the above-described third pressed surface X3 is provided between the front inner peripheral surface S31 and the rear inner peripheral surface S32. The third pressing surface Y <b> 3 here is an inclined surface that gradually decreases in diameter toward the rear, and is inclined with respect to the axial direction of the antenna 3.

With the above-described configuration, the third threaded surface Y3 of the pushing member S3 presses the third pushed surface X3 of the second ferrule S2 by screwing the female threaded part N2 of the pushing member S3 into the male threaded part N1 of the member Z. Then, the second ferrule S2 is pushed along the axial direction toward the first ferrule S1. Thereby, the second pressing surface Y2 of the second ferrule S2 presses the second pressed surface X2 of the first ferrule S1, and the first ferrule S1 is pressed toward the receiving member Z along the axial direction. Then, the first pressing surface Y1 of the first ferrule S1 is pressed against the first pressed surface X1 of the receiving member Z, the tip portion S1a of the first ferrule S1 is pressed and deformed, and the first pressing surface Y1 and the first pressed surface The space between the pressing surface X1 is kept airtight or liquid tight.
Further, in the process of sealing the gap between the first pressing surface Y1 and the first pressed surface X1 by screwing the pressing member S3 into the receiving member Z as described above, the first ferrule S1, the second ferrule S2, Since the one end Z1 of the receiving member Z is pressed and deformed in the radial direction, the receiving member Z, the first ferrule S1, and the second ferrule S2 thereby clamp and hold the metal pipe 31 integrally.

  As shown in FIG. 2, the antenna 3 configured as described above further includes a capacitor 33 which is a capacitive element electrically connected in series with the metal pipes 31 adjacent to each other. The capacitor 33 is provided inside the insulating pipe 32, and here is provided inside the flow path 32 x through which the coolant CL of the insulating pipe 32 flows.

  Specifically, the capacitor 33 includes a first electrode 33A electrically connected to one of the adjacent metal pipes 31 (first metal pipe 31A) and the other of the adjacent metal pipes 31 (second metal). A space between the first electrode 33A and the second electrode 33B, the second electrode 33B being electrically connected to the pipe 31B) and disposed opposite to the first electrode 33A. Is configured to be filled with the coolant CL. That is, the coolant CL that flows in the space between the first electrode 33 </ b> A and the second electrode 33 </ b> B becomes a dielectric that constitutes the capacitor 33.

  Each of the electrodes 33A and 33B has a substantially rotating body shape, and a main flow path 33x is formed at the center along the central axis. Specifically, the electrodes 33A and 33B have a cylindrical shape and are arranged coaxially with each other. Here, the inner diameter of the first electrode 33A is larger than the outer diameter of the second electrode 33B, and the second electrode 33B is inserted into the first electrode 33A. Thereby, a cylindrical space along the flow path direction is formed between the first electrode 33A and the second electrode 33B.

  Each of the electrodes 33A and 33B configured as described above is provided integrally with the receiving member Z described above. Here, although each electrode 33A, 33B and the receiving member Z are formed integrally from a single member, they may be formed by separate parts and joined together. In addition, the material of each electrode 33A, 33B is aluminum, copper, these alloys, etc., for example.

Since the electrodes 33A and 33B are integrally provided on the receiving member Z as described above, the first electrode 33A and the second electrode 33 are welded to the both ends of the insulating pipe 32 as described above. The electrodes 33B are arranged coaxially with each other, and the insertion dimension of the second electrode 33B with respect to the first electrode 33A is defined.
Then, the metal pipes 31A and 31B are inserted from the other end Z2 of the receiving member Z as described above, and are brought into contact with the abutting surface Za formed at the one end Z1 of the receiving member Z, whereby the first metal The pipe 31A is electrically connected to the first electrode 33A, and the second metal pipe 31B is electrically connected to the second electrode 33B.

In this configuration, when the coolant CL flows from the first metal pipe 31A, the coolant CL flows to the second electrode 33B side through the main channel 33x of the first electrode 33A. The coolant CL that has flowed to the second electrode 33B side flows to the second metal pipe 31B through the main flow path 33x of the second electrode 33B. At this time, the cylindrical space between the first electrode 33A and the second electrode 33B is filled with the cooling liquid CL, and the cooling liquid CL serves as a dielectric to constitute the capacitor 33.
A plurality of through holes Zh are formed in the thickness direction in one end portion Z1 of the receiving member Z. By providing such a through hole Zh, the flow resistance of the cooling liquid CL by the receiving member is reduced, and the retention of the cooling liquid CL in the insulating pipe 32 and the accumulation of bubbles in the insulating pipe 32 are prevented. Can be prevented.

<Effect of this embodiment>
According to the antenna 3 of the present embodiment configured as described above, the metal seal S that is more resistant to aging and thermal influence than the rubber O-ring is provided between the pair of metal pipes 31 and the insulating pipe 32. Therefore, even when the antenna 3 is lengthened, the sealing performance between the metal pipe 31 and the insulating pipe 32 can be ensured.
In addition, the receiving member Z is welded to the insulating pipe 32, and the receiving member Z, the first ferrule S1, and the second ferrule S2 integrally clamp and hold the metal pipe 31, so that each metal pipe 31 or insulating pipe is clamped. The shakiness of 32 can be suppressed, and sealing performance can be ensured also in this respect.

  In addition, since the receiving members Z provided at both ends of the insulating pipe 32 are made of a material stronger than the insulating pipe 32, the insulating pipe 32 is deformed when the metal seal S is pressed and deformed. The metal seal S can be reliably pressed and deformed.

  Furthermore, since the capacitor 33 is electrically connected in series with the pair of metal pipes 31, the combined reactance of the antenna 3 can be formed by subtracting the capacitive reactance from the inductive reactance. As a result, the impedance of the antenna 3 can be reduced, and even when the antenna 3 is lengthened, an increase in the impedance is suppressed, a high-frequency current is likely to flow through the antenna 3, and a uniform plasma P is efficiently generated. be able to.

  In addition, since each of the electrodes 33A and 33B is provided on the receiving member Z, if the receiving member Z is welded to the insulating pipe 32, the relative positional relationship between the first electrode 33A and the second electrode is defined. In addition, since the positional relationship between the electrodes 33A and 33B is maintained after welding, the reproducibility of the capacitance of the capacitor is not deteriorated. Moreover, since the receiving member Z and the insulating pipe 32 are welded, it is not necessary to provide a seal between them, and the number of parts can be reduced.

  In addition, since the first pressing surface Y1 of the first ferrule and the first pressed surface X1 of the receiving member Z are inclined surfaces and have components along the axial direction of the antenna 3, the first pressing surface Y1. And between the 1st to-be-pressed surfaces X1 can be surface-sealed. Thereby, for example, the first pressing surface Y1 and the first pressed surface X1 are surfaces perpendicular to the axial direction of the antenna 3, and the sealing performance is better than a configuration in which the space between them is axially sealed.

  Since the dielectric of the capacitor 33 is a liquid that fills the space between the first electrode 33A and the second electrode 33B, the gap generated between the electrodes 33A and 33B and the dielectric constituting the capacitor 33 is eliminated. Can do. As a result, arc discharge that can occur in the gaps between the electrodes 33A and 33B and the dielectric can be eliminated, and damage to the capacitor 33 due to arc discharge can be eliminated. Further, the capacitance value can be accurately set from the distance between the first electrode 33A and the second electrode 33B, the facing area, and the relative dielectric constant of the liquid dielectric without considering the gap. Further, the structure for pressing the electrodes 33A and 33B and the dielectric for filling the gap can be made unnecessary, and the structure around the antenna due to the pressing structure and the uniformity of the plasma P caused thereby are deteriorated. Can be prevented.

Since the dielectric is a coolant that flows inside the metal pipe 31, the metal pipe 31 that tends to become high temperature due to the heat generated during plasma generation can be cooled by the coolant CL. The peripheral structure can be prevented from being damaged, and the plasma P can be generated stably.
In addition, since the cooling liquid CL is used as the dielectric of the capacitor 33, the capacitor 33 can be cooled and unexpected capacitance variation can be suppressed.
Furthermore, by using the coolant CL as a dielectric while adjusting the temperature to a constant temperature by the temperature adjustment mechanism 141, it is possible to suppress a change in the relative permittivity due to a temperature change, and to suppress a change in the capacitance that occurs accordingly. Can do.

<Other modified embodiments>
The present invention is not limited to the above embodiment.

For example, as the metal seal S, a double ferrule type is used in the embodiment, but a metal gasket S4 may be used as shown in FIG.
More specifically, here, a flange F is provided at the end of the metal pipe 31, and the metal seal S is, for example, an annular metal gasket S4 disposed between the flange F and the receiving member Z. The metal gasket S4 is provided with a pushing member S3 for pushing toward the receiving member Z.
The pushing member S3 is configured to be screwed into the receiving member Z similarly to the above-described embodiment, and has a pressing surface Y4 that presses the back surface X4 of the flange F.

  With the above-described configuration, the pressing member S3 is screwed into the receiving member Z, so that the pressing surface Y4 of the pressing member S3 presses the back surface X4 of the flange F, and the metal pipe 31 extends along the axial direction toward the receiving member Z. And pushed. As a result, the metal gasket S4 is crushed between the flange F of the metal pipe 31 and the receiving member Z, and the space between them is kept airtight or liquid tight.

  Further, as shown in FIG. 5, the metal seal S may be one using a metal O-ring S5, or may be one using a single ferrule, although not shown.

  Furthermore, in the embodiment, the first pressed surface X1, the first pressed surface Y1, the second pressed surface X2, the second pressed surface Y2, the third pressed surface X3, and the third pressed surface Y3 are all antennas. However, a part of these planes X1 to X3 and Y1 to Y3 may be a plane perpendicular to the axial direction of the antenna 3.

  In the embodiment, the insulating pipe and the receiving member are integrated so as not to be separated by welding, but may be integrated by a joining method different from welding. Furthermore, the insulating pipe and the receiving member do not necessarily have to be integrated, and if the sealing property between them can be ensured, the receiving member can be detachably attached to the insulating pipe by, for example, screw fastening. good.

  In the plasma processing apparatus 100 of the embodiment, the antenna 3 is disposed in the processing chamber of the substrate W. However, the antenna 3 may be disposed outside the processing chamber 18 as shown in FIG. . In this case, the plurality of antennas 3 are arranged in an antenna chamber 20 that is partitioned from the processing chamber 18 by a dielectric window 19 in the vacuum vessel 2. The antenna chamber 20 is evacuated by the evacuation device 6. With this plasma processing apparatus 100, conditions such as the pressure in the processing chamber 18 and conditions such as the pressure in the antenna chamber 20 can be individually controlled, and the generation of plasma P can be efficiently performed, and the substrate W can be efficiently generated. Can be processed efficiently.

  In addition, the metal pipe and the insulating pipe have a tubular shape having one internal flow path, but may have two or more internal flow paths or have a branched internal flow path. good. Further, the metal pipe and the insulating pipe may be solid.

  In the electrode of the embodiment, the extending portion has a cylindrical shape, but may have another rectangular tube shape, a flat plate shape, or a curved or bent plate shape.

  In addition, it goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 100 ... Plasma processing apparatus W ... Board | substrate P ... Inductively coupled plasma 2 ... Vacuum container 3 ... Antenna 31 ... Metal pipe (conductor element)
32 ・ ・ ・ Insulated pipe (hollow insulator)
33 ... Capacitor 33A ... First electrode 33B ... Second electrode 4 ... High frequency power supply CL ... Coolant (liquid dielectric)
S ... Metal seal S1 ... First ferrule S2 ... Second ferrule S3 ... Pushing member Z ... Receiving member

Claims (8)

An antenna for generating plasma by flowing a high-frequency current,
At least a pair of cylindrical conductor elements;
A hollow insulator provided between the conductor elements adjacent to each other and communicating with the internal space of these conductor elements;
An antenna comprising: a metal seal provided between the pair of conductor elements and the hollow insulator. Further comprising receiving members provided at both ends of the hollow insulator and against which the metal seal hits;
The antenna according to claim 1, wherein the receiving member is made of a material stronger than the hollow insulator. A capacitive element electrically connected in series with the pair of conductor elements;
The capacitive element is
A first electrode electrically connected to one of the pair of conductor elements and extending to the other side of the pair of conductor elements through the interior of the hollow insulator;
A second electrode that is electrically connected to the other of the pair of conductor elements, extends to one side of the pair of conductor elements through the interior of the hollow insulator, and faces the first electrode; Have
The first electrode is provided on one of the receiving members;
The antenna according to claim 2, wherein the second electrode is provided on the other receiving member.   The antenna according to claim 3, wherein the receiving member is welded to the hollow insulator. The metal seal is
A first ferrule applied to the receiving member;
A second ferrule disposed closer to the conductor element than the first ferrule;
The antenna according to any one of claims 2 to 4, further comprising: a pushing member that pushes the second ferrule along the axial direction toward the first ferrule and is screwed into the receiving member.   The dielectric material of the said capacitive element is any one of the Claims 3, 4, or 5 which cites the claim 3 which is the liquid which fills the space between the said 1st electrode and the said 2nd electrode. The antenna according to item.   The antenna according to claim 6, wherein the dielectric is a coolant that flows inside the pair of conductor elements. An antenna according to any one of claims 1 to 7;
A vacuum vessel in which the antenna is arranged inside or outside;
A plasma processing apparatus, comprising: a high frequency power source that applies a high frequency current to the antenna.