JP7101335B2 - Antenna and plasma processing equipment - Google Patents

Description

The present invention relates to an antenna for generating inductively coupled plasma by passing a high frequency current, and a plasma processing apparatus provided with this antenna.

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 by the high frequency current, and the substrate is processed using this inductively coupled plasma. ..

In this type of plasma processing device, if the antenna is lengthened to accommodate a large substrate or the like, the impedance of the antenna becomes large, which causes a large potential difference between both ends of the antenna. As a result, there is a problem that the uniformity of plasma such as the density distribution, the potential distribution, and the electron temperature distribution of the plasma is deteriorated due to the influence of this large potential difference, and the uniformity of the substrate processing is deteriorated. Further, when the impedance of the antenna becomes large, there is a problem that it becomes 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 by interposing a hollow insulator between adjacent metal pipes, and are connected to the outer peripheral portion of the hollow insulator. It is considered that a capacitor, which is a capacitive element, is arranged. Specifically, a rubber O-ring is used between the outer peripheral surface of the metal pipe and the inner peripheral surface of the hollow insulator in order to screw-fasten the metal pipe and the hollow insulator and ensure the sealing property between them. The ring is intervening. Then, by electrically connecting the metal pipes screwed to both sides of the hollow insulator in series with the above-mentioned capacitive element, the synthetic reactance of the antenna is simply the inductive reactance minus the capacitive reactance. It will be a reactance. As a result, the impedance of the antenna can be reduced, the increase in the impedance is suppressed even when the antenna is lengthened, the high frequency current easily flows through the antenna, and plasma with good uniformity can be efficiently generated.

Japanese Unexamined Patent Publication No. 2016-138598

However, with the above-mentioned configuration, the elastic force of the O-ring is lowered due to deterioration over time, thermal influence, and the like, and it is difficult to ensure the sealing property for a long period of time.

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

That is, the antenna according to the present invention is an antenna for generating plasma by passing a high-frequency current, and is provided between at least a pair of tubular conductor elements and the conductor elements adjacent to each other. It is characterized by comprising 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.

In the case of an antenna configured in this way, a metal seal that is more resistant to aging and heat 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 property between the conductor element and the hollow insulator can be ensured.

If the hollow insulator is made of a material having a weaker strength than the metal seal such as resin, the hollow insulator will be deformed even if the metal seal is crushed, and the sealing property will be deteriorated.
Therefore, it is preferable that the receiving member provided at both ends of the hollow insulator and to which the metal seal hits is further provided, and the receiving member is made of a material having a higher strength 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 the deformation of the hollow insulator.

Further comprising a capacitive element electrically connected in series with the pair of conductor elements, the capacitive element is electrically connected to one of the pair of conductor elements and passes through the interior of the hollow insulator. The first electrode extending to the other side of the pair of conductor elements is electrically connected to the other of the pair of conductor elements, and one side of the pair of conductor elements passes through the inside of the hollow insulator. The first electrode has a second electrode facing the first electrode, the first electrode is provided on one of the receiving members, and the second electrode is the other receiving member. It is preferable that it is provided in.
In such a configuration, since the capacitive elements are electrically connected in series with the pair of conductor elements, the combined reactance of the antenna is made by subtracting the capacitive reactance from the inductive reactance, as described above. be able to. As a result, the impedance of the antenna can be reduced, the increase in the impedance is suppressed even when the antenna is lengthened, the high frequency current easily flows through the antenna, and plasma with good uniformity can be efficiently generated.
Moreover, 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 face each other, and the capacitance can be increased. The element can be easily formed.

When the receiving member is detachably provided on the hollow insulator, the relative positional relationship between the first electrode and the second electrode may change each time the receiving member is attached to the hollow insulator, so that the capacitance element is static. The reproducibility of the electric capacity 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 together, 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, the first ferrule corresponding to the receiving member, the second ferrule arranged on the conductor element side of the first ferrule, and the second ferrule along the axial direction are described. 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, surface sealing can be performed between the receiving member and the first ferrule, so that the sealing property is higher than that of a shaft seal using, for example, 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 the 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 the gap generated between the electrodes and the dielectric constituting the capacitive element. can. As a result, it is possible to eliminate the arc discharge that may occur in the gap between the electrode and the dielectric, and to eliminate the damage of the capacitive element due to the arc discharge. Further, the capacitance value can be set accurately from the distance between the first electrode and the second electrode, the facing area, and the relative permittivity of the liquid dielectric without considering the gap. Further, it is possible to eliminate the need for a structure for pressing the electrode and the dielectric for filling the gap, and it is possible to prevent the structure around the antenna from becoming complicated and the resulting deterioration of plasma uniformity due to the pressing structure.

It is preferable that the dielectric is a coolant flowing inside the pair of conductor elements.
With such a configuration, the antenna, which tends to become hot due to the heat generated during plasma generation, can be cooled by the coolant, so that it is possible to prevent damage to the antenna itself or damage to its peripheral structure, and it is stable. It becomes possible to generate plasma.
Moreover, since the coolant 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 coolant as a dielectric while adjusting it 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 accompany it. ..

Further, the plasma processing apparatus according to the present invention is characterized by including the above-mentioned antenna, a vacuum container in which the antenna is arranged inside or outside, and a high-frequency power source for applying a high-frequency current to the antenna. Is.
With the plasma processing device configured in this way, the same operation and effect as the above-mentioned antenna can be obtained.

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

It is a vertical sectional view schematically showing the structure of the plasma processing apparatus of this embodiment. It is an enlarged sectional view schematically showing the peripheral structure of the antenna of the same embodiment. It is a schematic diagram which shows the structure of the metal seal of the same embodiment. It is a schematic diagram which shows the structure of the metal seal of the modification embodiment. It is a schematic diagram which shows the structure of the metal seal of the modification embodiment. It is a vertical sectional view schematically showing the structure of the plasma processing apparatus of a modification embodiment.

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

<Device configuration>
The plasma processing apparatus 100 of the present embodiment processes the substrate W using an 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, and the like. The processing applied to the substrate W is, for example, film formation, etching, ashing, sputtering, or the like by a plasma CVD method.

The plasma processing apparatus 100 includes a plasma CVD apparatus when forming a film by a plasma CVD method, a plasma etching apparatus when performing etching, a plasma ashing apparatus when performing ashing, and a plasma sputtering apparatus when performing sputtering. be called.

Specifically, as shown in FIG. 1, the plasma processing apparatus 100 includes a vacuum container 2 that is evacuated and into which a gas 7 is introduced, a linear antenna 3 arranged in the vacuum container 2, and a vacuum container 2. It is provided with a high frequency power supply 4 that applies a high frequency for generating an inductively coupled plasma P to the antenna 3. By applying a high frequency from the high frequency power supply 4 to the antenna 3, a high frequency current IR flows through the antenna 3, an inductive electric field is generated in the vacuum vessel 2, and an inductively coupled plasma P is generated.

The vacuum container 2 is, for example, a metal container, and the inside thereof is evacuated by the vacuum exhaust 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 walls of the vacuum vessel 2. The gas 7 may be set according to the processing content to be applied to the substrate W. For example, when a film is formed on the substrate W by the plasma CVD method, the gas 7 is a raw material gas or a gas obtained by diluting the raw material gas ₍ for example, H2). More specifically, when the raw material gas is SiH ₄ , a Si film is used, when SiH ₄ + NH ₃ is used, a SiN film is used, when SiH ₄ + O ₂ is used, a SiO ₂ film is used, and when SiF ₄ + N ₂ is used, SiN is used. : The F film (fluorinated silicon nitride film) can be formed on the substrate W, respectively.

Further, a substrate holder 8 for holding 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 the 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 arranged above the substrate W in the vacuum vessel 2 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 container 2 may be one or a plurality.

The vicinity of both ends of the antenna 3 penetrates the side walls facing each other of the vacuum vessel 2. Insulating members 11 are provided at portions that allow both ends of the antenna 3 to penetrate the outside of the vacuum vessel 2. Both ends of the antenna 3 penetrate each of the insulating members 11, and the penetrating portions are vacuum-sealed by, for example, packing 12. The space between each insulating member 11 and the vacuum container 2 is 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 plastics such as polyphenylene sulfide (PPS) and polyetheretherketone (PEEK).

Further, in the antenna 3, a portion located inside the vacuum container 2 is covered with a straight tubular insulating cover 10. Both ends of the insulating cover 10 are supported by the insulating member 11. It is not necessary to seal between both ends of the insulating cover 10 and the insulating member 11. This is because even if the gas 7 enters the space inside the insulating cover 10, plasma P is not normally generated in the space because the space is small and the moving distance of electrons is short. 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 suppress the incident of charged particles in the plasma P on the metal pipe 31 constituting the antenna 3, so that the charged particles (mainly electrons) are incident on the metal pipe 31. It is possible to suppress an increase in the plasma potential and to prevent the metal pipe 31 from being sputtered by charged particles (mainly ions) to cause metal contamination (metal contamination) on the plasma P and the substrate W. ..

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

With the above configuration, a high frequency current IR can be passed from the high frequency power supply 4 to the antenna 3 via the matching circuit 41. The frequency of the high frequency current IR is, for example, 13.56 MHz, which is general, but is not limited to this.

The antenna 3 has a hollow structure having a flow path through which the coolant CL flows. The coolant CL circulates the antenna 3 through a circulation flow path 14 provided outside the vacuum vessel 2, and the circulation flow path 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 coolant CL, water having high resistance is preferable from the viewpoint of electrical insulation, and for example, pure water or water close to it 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 pipe 31”) and metal pipes 31 adjacent to each other. Further, it is provided with a tubular hollow insulator 32 (hereinafter, referred to as “insulated pipe 32”) that insulates the metal pipes 31.

In this 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 a "first metal pipe 31A", and the other metal pipe is also referred to as a "second metal pipe 31B". The antenna 3 may be configured to have three or more metal pipes 31, in which case the number of insulating pipes 32 is one less than the number of metal pipes 31.

The metal pipe 31 has a straight tubular shape in which a linear flow path 31x through which the coolant 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 tubular shape in which a linear flow path 32x through which the coolant CL flows is formed. Although the insulating pipe 32 of the present embodiment is formed from a single member, it may be formed by joining a plurality of members. The material of the insulating pipe 32 is, for example, alumina, fluororesin, polyethylene (PE), engineering plastic (for example, polyphenylene sulfide (PPS), polyetheretherketone (PEEK), etc.) and the like.

Then, as shown in FIGS. 2 and 3, the antenna 3 of the present embodiment is between the first metal pipe 31A and the insulating pipe 32, and between the second metal pipe 31B and the insulating pipe 32, respectively. The metal seal S provided in the above is provided.

More specifically, the metal seal S is for ensuring the sealing property between each of the metal pipes 31A and B and the insulating pipe 32, and here, the receivers provided at both ends of the insulating pipe 32. It is configured so that at least a part thereof is pressed and deformed by being pressed against the member Z.

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 having a higher strength than the insulating pipe 32, such as aluminum and copper. It is made of metal such as alloy.

As shown in FIG. 2, the receiving member Z communicates with the insulating pipe 32, and one end portion Z1 fits into the countersunk portion 321 that seats the inner wall of the insulating pipe 32, and the other end portion Z2. The end portion 31t of the metal pipe 31 is inserted from. 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 here, and is the inner diameter of the receiving member Z substantially the same as the outer diameter of the end portion 31t of the metal pipe 31? Slightly large.

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

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 shape that gradually expands in diameter from the one end Z1 side to the other end Z2 side. It is a surface and is inclined with respect to the axial direction of the antenna 3. Further, a male screw portion N1 is formed on the outer peripheral surface of the other end portion Z2, and is configured so that a pushing member S3, which is a component of the metal seal S described later, is screwed.

In the receiving member Z, a large diameter portion Z3 having a larger outer diameter than the insulating pipe 32 is provided between the one end portion Z1 and the other end portion Z2. Then, the large diameter portion Z3 is brought into contact with the end surface 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 inseparably.

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, this metal seal S has a first ferrule S1 pressed against the receiving member Z, a second ferrule S2 located closer to the metal pipe 31 than the first ferrule S1, and a second ferrule S2 on the metal pipe 31 side. It has a pushing member S3 that pushes toward the first ferrule S1 side. The first ferrule S1, the second ferrule S2, and the pushing member S3 have a ring shape that is fitted onto the end portion 31t of the metal pipe 31, and here, the same material as the metal pipe 31, that is, copper, aluminum, is used. Although it is made of these alloys, stainless steel, etc., it may be made of a material different from that of 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 portion 31t of the metal pipe 31, the rear end portion S1b is pushed by the second ferrule S2, and the tip portion S1a is attached to the receiving member Z. It is something that is pushed in. The outer peripheral surface of the first ferrule S1 is a truncated cone-shaped inclined surface whose diameter gradually increases from the front end portion S1a toward the rear end portion S1b. The tip S1a side of the outer peripheral surface is formed as the first pressing surface Y1 pressed against the first pressed surface X1 described above, and is inclined with respect to the axial direction of the antenna 3. Further, a second pressed surface X2 to which the tip end portion S2a of the second ferrule S2 is pressed is formed on the rear end portion S1b of the first ferrule S1. The second pressed surface X2 is formed by cutting out, for example, the rear end portion S1b of the first ferrule S1, and is set here on the inner peripheral surface of the rear end portion S1b. The second pressed surface X2 here is an inclined surface whose diameter gradually increases 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 surface that gradually expands in diameter from the front inner peripheral surface S21 toward the rear. It has a peripheral surface S22, and the rear end portion S2b is pushed by the pushing member S3, and the front end portion S2a is pushed into the rear end portion S1b of the first ferrule S1. A second pressing surface Y2 that is pressed against the above-mentioned second pressed surface X2 is formed on the tip portion S2a of the second ferrule S2. The second pressing surface Y2 is, for example, an inclined surface whose diameter gradually increases toward the rear from the tip portion S2a, and is inclined with respect to the axial direction of the antenna 3. Further, on the rear end portion S2b of the second ferrule S2, a third pressed surface X3 pressed by the pushing member S3 and an annular protruding portion S23 protruding radially inward from the rear inner peripheral surface S22 are formed. ing. The third pressed surface X3 is an inclined surface whose diameter gradually decreases toward the rear, and is inclined with respect to the axial direction of the antenna 3. By inclining the third pressed surface X3 in this way, when the pushing member S3 pushes the second ferrule S2 toward the first ferrule S1, a force for pressing the second ferrule S2 inward in the radial direction is generated. .. As a result, the annular protrusion S23 is pressed and deformed so as to contract toward the outer peripheral surface of the metal pipe 31, and the second ferrule S2 is fixed to the metal pipe 31.

The pushing member S3 has substantially the outer diameter of the front inner peripheral surface S31 on which the female threaded portion N2 screwed to the male threaded portion N1 formed on the outer peripheral surface of the receiving member Z described above is formed and the end portion 31t of the metal pipe 31. It has 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 for pressing the above-mentioned third pressed surface X3 is provided between the front inner peripheral surface S31 and the rear inner peripheral surface S32. Here, the third pressing surface Y3 is an inclined surface whose diameter gradually decreases toward the rear, and is inclined with respect to the axial direction of the antenna 3.

With the above configuration, the third pressing surface Y3 of the pushing member S3 presses the third pressed surface X3 of the second ferrule S2 by receiving the female threaded portion N2 of the pushing member S3 and screwing it into the male threaded portion N1 of the member Z. Then, the second ferrule S2 is pushed toward the first ferrule S1 along the axial direction. As a result, the second pressed surface Y2 of the second ferrule S2 presses the second pressed surface X2 of the first ferrule S1, and the first ferrule S1 is pushed along the axial direction toward the receiving member Z. 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 cover are pressed. The space between the pressing surface X1 and the pressing surface X1 is maintained to be airtight or liquidtight.
Further, in the process of receiving the pushing member S3 and screwing it into the member Z to seal between the first pressed surface Y1 and the first pressed surface X1, the first ferrule S1 and the second ferrule S2 Since one end portion 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 integrally tighten and sandwich the metal pipe 31.

As shown in FIG. 2, the antenna 3 configured in this way further includes a capacitor 33, which is a capacitive element electrically connected in series with 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 32x through which the coolant CL of the insulating pipe 32 flows.

Specifically, the capacitor 33 has a first electrode 33A electrically connected to one of the metal pipes 31 adjacent to each other (first metal pipe 31A) and the other of the metal pipes 31 adjacent to each other (second metal). It is electrically connected to the pipe 31B) and has a second electrode 33B arranged so as to face the first electrode 33A, and is provided with a space between the first electrode 33A and the second electrode 33B. Is configured to be filled with the coolant CL. That is, the coolant CL flowing in the space between the first electrode 33A and the second electrode 33B becomes the dielectric constituting the capacitor 33.

Each of the electrodes 33A and 33B has a substantially rotating body shape, and a main flow path 33x is formed in the central portion along the central axis thereof. 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 inside the first electrode 33A. As a result, a cylindrical space along the flow path direction is formed between the first electrode 33A and the second electrode 33B.

The electrodes 33A and 33B configured in this way are integrally provided on the receiving member Z described above. Here, the electrodes 33A and 33B and the receiving member Z are formed from a single member and integrally provided, but these may be formed by different parts and joined to each other. The materials of the electrodes 33A and 33B are, for example, aluminum, copper, alloys thereof, and the like.

Since the receiving members 33A and 33B are integrally provided on the receiving member Z in this way, by welding the receiving member Z to both ends of the insulating pipe 32 as described above, the first electrodes 33A and the second electrodes 33A and the second are provided. 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, as described above, the metal pipes 31A and 31B are inserted from the other end Z2 of the receiving member Z and brought into contact with the contact surface Za formed on the one end Z1 of the receiving member Z to bring the first metal into contact with 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 flow path 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 coolant CL, and the coolant CL becomes a dielectric to form the capacitor 33.
A plurality of through holes Zh are formed in the one end portion Z1 of the receiving member Z in the thickness direction. By providing such a through hole Zh, the flow path resistance of the coolant CL due to the receiving member is reduced, the coolant CL stays in the insulating pipe 32, and air bubbles are accumulated in the insulating pipe 32. Can be prevented.

<Effect of this embodiment>
According to the antenna 3 of the present embodiment configured in this way, a metal seal S that is more resistant to aging and heat influence than the rubber O-ring is provided between the pair of metal pipes 31 and the insulating pipe 32, respectively. Therefore, even when the antenna 3 is lengthened, the sealing property between the metal pipe 31 and the insulating pipe 32 can be ensured.
Moreover, since 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 tighten and sandwich the metal pipe 31, each metal pipe 31 and the insulating pipe are sandwiched. The rattling of 32 can be suppressed, and the sealing property can be ensured in this respect as well.

Further, since the receiving members Z provided at both ends of the insulating pipe 32 are made of a material having a higher strength than the insulating pipe 32, the insulating pipe 32 is deformed when the metal seal S is pressed and deformed. This can be prevented, and the metal seal S can be reliably pressed and deformed.

Further, 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 made by subtracting the capacitive reactance from the inductive reactance. As a result, the impedance of the antenna 3 can be reduced, the increase in the impedance is suppressed even when the antenna 3 is lengthened, the high frequency current easily flows through the antenna 3, and the plasma P having good uniformity is efficiently generated. be able to.

Moreover, 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. 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 together, 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 the space between the first pressed surface X1 can be surface-sealed. As a result, 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 property is better than the configuration in which the two are 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, it is necessary to eliminate the gap generated between the electrodes 33A, 33B and the dielectric constituting the capacitor 33. Can be done. As a result, it is possible to eliminate the arc discharge that may occur in the gap between the electrodes 33A and 33B and the dielectric, and to eliminate the damage of the capacitor 33 due to the arc discharge. 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 permittivity 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 eliminated, and the structure around the antenna is complicated by the pressing structure and the uniformity of the plasma P caused by the pressing structure is deteriorated. Can be prevented.

Since the dielectric is a coolant that flows inside the metal pipe 31, the metal pipe 31, which tends to become hot due to the heat generated during plasma generation, can be cooled by the coolant CL, so that the antenna 3 itself is damaged or its own. It is possible to prevent damage to the peripheral structure and to stably generate plasma P.
Moreover, since the coolant CL is used as the dielectric of the capacitor 33, it is possible to suppress unexpected fluctuations in the capacitance while cooling the capacitor 33.
Furthermore, by using the coolant CL as a dielectric while adjusting it to a constant temperature by the temperature control mechanism 141, it is possible to suppress the change in the relative permittivity due to the temperature change, and it is possible to suppress the change in the capacitance that accompanies it. Can be done.

<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 above embodiment, but as shown in FIG. 4, a metal gasket S4 may be used.
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 arranged between the flange F and the receiving member Z. The metal gasket S4 is provided with a pushing member S3 for pushing the metal gasket S4 toward the member Z.
The pushing member S3 is configured to be screwed into the receiving member Z as in the embodiment, and has a pressing surface Y4 for pressing the back surface X4 of the flange F.

According to the above-described configuration, by screwing the pushing member S3 into the receiving member Z, the pressing surface Y4 of the pushing member S3 presses the back surface X4 of the flange F, and the metal pipe 31 is axially along the receiving member Z. Is pushed in. 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 liquidtight.

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

Further, in the above 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. Although it was an inclined surface inclined with respect to the axial direction of 3, a part of these surfaces X1 to X3 and Y1 to Y3 may be a surface perpendicular to the axial direction of the antenna 3.

In the above embodiment, the insulating pipe and the receiving member are inseparably integrated by welding, but they may be integrated by a joining method different from welding. Further, the insulating pipe and the receiving member do not necessarily have to be integrated, and if the sealing property between them can be ensured, even if the receiving member is detachably provided to the insulating pipe by, for example, screwing. good.

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

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

In the electrode of the above embodiment, the extending portion has a cylindrical shape, but may be another square tubular shape, a flat plate shape, or a curved or bent plate shape.

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

100 ... Plasma processing device W ... Substrate P ... Inductively coupled plasma 2 ... Vacuum container 3 ... Antenna 31 ... Metal pipe (conductor element)
32 ... Insulation pipe (hollow insulator)
33 ... Capacitor 33A ... First electrode 33B ... Second electrode 4 ... High frequency power supply CL ... Coolant (liquid dielectric)
S ・ ・ ・ Metal seal S1 ・ ・ ・ 1st ferrule S2 ・ ・ ・ 2nd ferrule S3 ・ ・ ・ Pushing member Z ・ ・ ・ Receiving member

Claims (8)

It is an antenna for generating plasma by passing a high frequency current.
With 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 provided between the pair of conductor elements and the hollow insulator, and provided with a metal seal which is a member different from the hollow insulator . Further provided with receiving members provided at both ends of the hollow insulator and to which the metal seal abuts are provided.
The antenna according to claim 1, wherein the receiving member is made of a material having a strength stronger than that of the hollow insulator. Further comprising a capacitive element electrically connected in series with the pair of conductor elements
The capacitive element
A first electrode that is electrically connected to one of the pair of conductor elements and extends through the interior of the hollow insulator to the other side of the pair of conductor elements.
A second electrode that is electrically connected to the other of the pair of conductor elements and extends to one side of the pair of conductor elements through the inside of the hollow insulator and faces the first electrode. Have and
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
The first ferrule applied to the receiving member and
A second ferrule arranged 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 toward the first ferrule side along the axial direction and is screwed into the receiving member. Any one of claims 3 and 4, or claim 5 quoting claim 3, wherein the dielectric of the capacitive element is a liquid that fills the space between the first electrode and the second electrode. The antenna described in the section. The antenna according to claim 6, wherein the dielectric is a coolant flowing inside the pair of conductor elements. The antenna according to any one of claims 1 to 7.
A vacuum container in which the antenna is arranged inside or outside,
A plasma processing apparatus including a high frequency power supply that applies a high frequency current to the antenna.

Images