JP7290065B2 - Plasma processing equipment - Google Patents

Description

The present invention relates to a plasma processing apparatus that generates plasma in a vacuum chamber and processes a substrate using the plasma.

As disclosed in Japanese Unexamined Patent Application Publication No. 2002-100002, there is a plasma processing apparatus of this type in which a plurality of antenna conductors are arranged in a plasma generation chamber and a variable capacitor is connected between adjacent antenna conductors.

According to this configuration, by changing the capacitance of the variable capacitor, the high-frequency current distribution on the antenna conductor can be changed, and the density distribution of the inductively coupled plasma generated by this current can be controlled. can.

However, when a variable capacitor is used in this way, the dielectric constant of the variable capacitor changes due to the heat generated during plasma generation, causing the capacitance to fluctuate unexpectedly. is difficult.

Therefore, the inventor of the present application has come up with a configuration in which the cooling liquid flowing through the antenna conductor is used as the dielectric of the variable capacitor to cool the variable capacitor with the cooling liquid, in order to suppress unexpected fluctuations in the capacitance.

However, even if the unexpected fluctuation of the capacitance is suppressed in this way, the reactance of the variable capacitor is proportional to the reciprocal of the capacitance, so as shown in FIG. In this case, a slight change in capacitance causes a large change in reactance, and stable adjustment of reactance is still difficult.

If the total capacitance of the variable capacitor is reduced, the change in reactance can be suppressed. A capacitor needs to be additionally connected, which complicates the connection with the antenna conductor and increases the size of the entire device.

JP-A-11-317299

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above problems. The main problem is to stably adjust the reactance without increasing the size of the device.

That is, a plasma processing apparatus according to the present invention is a plasma processing apparatus that generates plasma in a vacuum vessel and processes a substrate using the plasma, and includes an antenna for generating plasma by flowing a high-frequency current. a conductor and a variable capacitor electrically connected to the antenna conductor, the antenna conductor having a flow path in which cooling liquid flows, and the dielectric of the variable capacitor connecting the antenna conductor with the antenna conductor. The variable capacitor comprises a flowing coolant and has a fixed electrode electrically connected to the antenna conductor and a movable electrode forming a capacitor therebetween, the movable electrode comprising: a capacitance changing unit that moves so as to change the area facing the fixed electrode to change the capacitance of the variable capacitor; It is characterized by having a capacity holding part for holding the capacitance of the capacitor above a certain level.

According to the plasma processing apparatus constructed in this manner, the dielectric of the variable capacitor is composed of the coolant flowing through the antenna conductor, so that the variable capacitor can be cooled while suppressing unexpected fluctuations in its capacitance. can be done.
In addition, since the movable electrode has a capacitance holding section that maintains the capacitance of the variable capacitor at a certain level or more, it is possible to reduce the amount of change in reactance when the capacitance is changed by the capacitance changing section. , stable adjustment of the reactance becomes possible.
Moreover, since the capacitance holding part keeps the static capacitance of the variable capacitor at a certain level or more, the reactance of the variable capacitor can be kept at a certain level or more, and the impedance with the antenna conductor can be adjusted without additionally connecting a separate capacitor. This avoids complicating the connection with the antenna conductor and increasing the size of the device.

It is preferable that the capacitance holding portion has one or a plurality of metal plates that are generally circular in plan view.
With such a configuration, the capacitance held by the capacitance holding section can be kept constant without being varied, and the reactance of the variable capacitor can be adjusted with high accuracy.

It is preferable that each of the plurality of metal plates forming the capacitance holding portion has a disk shape.
With such a configuration, the capacitance can be kept constant, and the configuration of the capacitance holding section can be simplified.

The variable capacitor has a second fixed electrode that is electrically connected to an antenna conductor different from the antenna conductor or grounded, and the capacitance changing section has a first capacitance between the fixed electrode and the fixed electrode. It is desirable to have a movable electrode forming a capacitor and forming a second capacitor with said second fixed electrode.
With this configuration, it is not necessary to connect an external circuit element (eg, an antenna conductor or ground) to the movable electrode. As a result, it is possible to eliminate the need for a connector using a slider (brush) for bringing the movable electrode into contact with an external circuit element, thereby reducing poor connection caused by a connector using a slider.

According to the present invention configured as described above, the variable capacitor connected to the antenna conductor can be cooled to suppress unexpected fluctuations in the capacitance thereof, and the reactance can be stably adjusted.

1 is a longitudinal sectional view schematically showing the configuration of a plasma processing apparatus of this embodiment; FIG. It is a cross-sectional view which shows typically the structure of the plasma processing apparatus of the same embodiment. It is a cross-sectional view which shows typically the connection conductor of the same embodiment. It is a longitudinal cross-sectional view which shows typically the connection conductor of the same embodiment. It is the side view which looked at the variable capacitor of the same embodiment from the introduction port side. It is a schematic diagram which shows the state which the fixed metal plate and movable metal plate of the same embodiment do not oppose. It is a perspective view of the movable electrode of the same embodiment. It is a schematic diagram which shows the state which the fixed metal plate and the 1st and 2nd movable metal plates of the same embodiment faced. 4 is a graph showing the relationship between reactance, rotation angle, and capacitance of the variable capacitor of the same embodiment; FIG. 10 is a perspective view of a movable electrode in another embodiment; FIG. 10 is a perspective view of a movable electrode in another embodiment; A graph showing the relationship between reactance, rotation angle, and capacitance of a conventional variable capacitor.

An embodiment of a plasma processing apparatus according to the present invention will be described below with reference to the drawings.

<Device configuration>
The plasma processing apparatus 100 of this embodiment processes a substrate W using an inductively coupled plasma P. As shown in FIG. Here, 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. Further, the processing applied to the substrate W includes, for example, film formation by plasma CVD, etching, ashing, sputtering, and the like.

The plasma processing apparatus 100 is also referred to as a plasma CVD apparatus for film formation by plasma CVD, a plasma etching apparatus for etching, a plasma ashing apparatus for ashing, and a plasma sputtering apparatus for sputtering. Called.

Specifically, as shown in FIGS. 1 and 2, the plasma processing apparatus 100 includes a vacuum vessel 2 which is evacuated and into which gas G is introduced, a linear antenna conductor 3 arranged in the vacuum vessel 2, A high frequency power source 4 for applying a high frequency to the antenna conductor 3 for generating an inductively coupled plasma P is provided in the vacuum chamber 2 . By applying a high frequency to the antenna conductor 3 from a high frequency power supply 4, a high frequency current IR flows through the antenna conductor 3, an induced 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 container made of metal, and its interior is evacuated by an evacuation device 5 . The vacuum vessel 2 is electrically grounded in this example.

A gas G is introduced into the vacuum container 2 via, for example, a flow rate regulator (not shown) and a plurality of gas introduction ports 21 arranged in a direction along the antenna conductor 3 . The gas G may be selected according to the content of the processing to be performed on the substrate W. FIG.

A substrate holder 6 for holding the substrate W is provided inside the vacuum chamber 2 . A bias voltage may be applied to the substrate holder 6 from the bias power supply 7 as in this example. The bias voltage is, for example, a negative DC voltage, a negative bias voltage, or the like, but is not limited to these. With such a bias voltage, for example, the energy of positive ions in the plasma P when they impinge on the substrate W can be controlled, and the crystallinity of the film formed on the surface of the substrate W can be controlled. . A heater 61 for heating the substrate W may be provided in the substrate holder 6 .

A plurality of antenna conductors 3 are 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 vicinity of both end portions of the antenna conductor 3 penetrate through the side walls facing each other of the vacuum vessel 2 . Insulating members 8 are provided at portions where both end portions of the antenna conductor 3 are penetrated to the outside of the vacuum vessel 2 . Both ends of the antenna conductor 3 pass through each insulating member 8 , and the through portions are vacuum-sealed by packing 91 , for example. The space between each insulating member 8 and the vacuum vessel 2 is also vacuum-sealed by, for example, a packing 92 . The material of the insulating member 8 is, for example, ceramics such as alumina, quartz, or engineering plastics such as polyphenylene sulfide (PPS) and polyetheretherketone (PEEK).

Further, a portion of the antenna conductor 3 located inside 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 8 . In addition, the material of the insulating cover 10 is, for example, quartz, alumina, fluororesin, silicon nitride, silicon carbide, silicon, or the like.

The plurality of antenna conductors 3 have a hollow structure having flow paths 3S through which the cooling liquid CL flows. In this embodiment, it is a straight metal pipe. The material of the metal pipe 31 is, for example, copper, aluminum, alloys thereof, stainless steel, or the like.

The cooling liquid CL circulates through the antenna conductor 3 through a circulation passage 11 provided outside the vacuum vessel 2. The circulation passage 11 is provided with a heater for adjusting the temperature of the cooling liquid CL to a constant temperature. A temperature control mechanism 111 such as a heat exchanger and a circulation mechanism 112 such as a pump for circulating the coolant CL in the circulation flow path 11 are provided. From the viewpoint of electrical insulation, the cooling liquid CL is preferably high-resistance water, such as pure water or water close thereto. In addition, liquid refrigerants other than water, such as fluorine-based inert liquids, may be used.

Moreover, as shown in FIG. 2, the plurality of antenna conductors 3 are connected by connecting conductors 12 to form a single antenna structure. That is, the connection conductors 12 electrically connect the ends of the adjacent antenna conductors 3 extending outside the vacuum vessel 2 . Specifically, in the antenna conductors 3 adjacent to each other, the end portion of one antenna conductor 3 and the end portion of the other antenna conductor 3 are electrically connected by a connection conductor 12 .

Here, the ends of the two antenna conductors 3 connected by the connection conductor 12 are located on the same side wall. As a result, the plurality of antenna conductors 3 are configured such that high-frequency currents in opposite directions flow through adjacent antenna conductors 3 .

The connection conductor 12 has a flow path inside, and the cooling liquid CL is configured to flow through the flow path. Specifically, one end of the connection conductor 12 communicates with the channel of one antenna conductor 3 , and the other end of the connection conductor 12 communicates with the channel of the other antenna conductor 3 . As a result, the coolant CL that has flowed through one of the antenna conductors 3 adjacent to each other flows through the flow path of the connection conductor 12 to the other antenna conductor 3 . Thereby, the plurality of antenna conductors 3 can be cooled by the common cooling liquid CL. Moreover, since a plurality of antenna conductors 3 can be cooled by one channel, the configuration of the circulation channel 11 can be simplified.

One end of the plurality of antenna conductors 3 that is not connected by the connection conductor 12 serves as a feed end 3 a , and the high frequency power supply 4 is connected to the feed end 3 a through a matching circuit 41 . The terminal portion 3b, which is the other end portion, is directly grounded. Note that the terminal portion 3b may be grounded through 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 conductor 3 via the matching circuit 41 . The frequency of the high frequency is, for example, the general 13.56 MHz, but is not limited to this.

<Configuration of Connection Conductor 12>
Next, the connection conductor 12 will be described in detail with reference to FIGS. 3 to 7. FIG. 3 and 4, some seal members are omitted.

As shown in FIGS. 3 and 4, the connection conductor 12 includes a variable capacitor 13 electrically connected to the antenna conductor 3 and a first capacitor connecting the variable capacitor 13 and one end of the antenna conductor 3 . It has a connecting portion 14 and a second connecting portion 15 connecting the variable capacitor 13 and the other end of the antenna conductor 3 .

The first connection portion 14 and the second connection portion 15 surround the end portion of the antenna conductor 3 so as to be in electrical contact with the antenna conductor 3 , and the opening portion 3</b>H formed at the end portion of the antenna conductor 3 . , the cooling liquid CL is led to the variable capacitor 13 from the . The materials of these connecting portions 14 and 15 are, for example, copper, aluminum, alloys thereof, stainless steel, and the like.

Each of the connecting portions 14 and 15 of the present embodiment is mounted liquid-tightly at the end portion of the antenna conductor 3 on the side of the vacuum vessel 2 from the opening portion 3H via a sealing member S1 such as an O-ring. It is configured so as not to constrain the outside of the opening 3H (see FIG. 3). As a result, a slight inclination of the antenna conductor 3 with respect to the connecting portions 14 and 15 is allowed.

The variable capacitor 13 has a first fixed electrode 16 electrically connected to one antenna conductor 3, a second fixed electrode 17 electrically connected to the other antenna conductor 3, and a first fixed electrode 17 electrically connected to the other antenna conductor 3. 16 forming a first capacitor and a second fixed electrode 17 forming a second capacitor.

The variable capacitor 13 of this embodiment is configured such that the electrostatic capacity thereof can be changed by rotating the movable electrode 18 around a predetermined rotation axis C. As shown in FIG. The variable capacitor 13 includes an insulating container 19 that accommodates the first fixed electrode 16 , the second fixed electrode 17 and the movable electrode 18 .

The container 19 has an introduction port P1 for introducing the coolant CL from one antenna conductor 3 and an outlet port P2 for leading the coolant CL to the other antenna conductor 3 . The introduction port P1 is formed in one side wall of the container 134 (the left side wall 19a in FIG. 3), and the outlet port P2 is formed in the other side wall of the container 19 (the right side wall 19b in FIG. 3). The port P1 and the lead-out port P2 are provided at positions facing each other. Note that the storage container 19 of the present embodiment has a substantially rectangular parallelepiped shape having a hollow portion inside, but may have other shapes.

The first fixed electrode 16 and the second fixed electrode 17 are provided at different positions around the rotation axis C of the movable electrode 18 . In this embodiment, the first fixed electrode 16 is provided by inserting it into the storage container 19 from the introduction port P1 of the storage container 19 . Also, the second fixed electrode 17 is provided by being inserted into the container 19 from the lead-out port P2 of the container 19 . Thereby, the first fixed electrode 16 and the second fixed electrode 17 are provided at symmetrical positions with respect to the rotation axis C. As shown in FIG.

The first fixed electrode 16 has a plurality of first fixed metal plates 161 facing each other. The second fixed electrode 17 also has a plurality of second fixed metal plates 171 facing each other. These fixed metal plates 161 and 171 are provided along the rotation axis C at approximately equal intervals.

The plurality of first fixed metal plates 161 have the same shape and are supported by the first flange member 162 . The first flange member 162 is fixed to the left side wall 19a of the container 19 where the introduction port P1 is formed. A through hole 162H communicating with the introduction port P1 is formed in the first flange member 162 (see FIG. 5). The plurality of second fixed metal plates 171 have the same shape and are supported by the second flange member 172 . The second flange member 172 is fixed to the right side wall 19b of the container 19 where the lead-out port P2 is formed. Here, the second flange member 172 is formed with a through hole 172H that communicates with the lead-out port P2. The plurality of first fixed metal plates 161 and the plurality of second fixed metal plates 171 are provided at symmetrical positions with respect to the rotation axis C while being fixed to the container 19 .

In addition, the first fixed metal plate 161 and the second fixed metal plate 171 are plate-shaped, and as shown in FIG. ing. Edge sides 161a and 171a of the fixed metal plates 161 and 171 are formed along the radial direction of the rotation axis C, the widths of which are reduced. The angle formed by the edges 161a and 171a facing each other is 90 degrees. Further, tip sides 161b and 171b of the fixed metal plates 161 and 171 on the rotation axis C side are arcuate.

The movable electrode 18, as shown in FIG. It has a capacitance changing portion 18A that is supported and moves so as to change the facing area with the fixed electrodes 16 and 17 to change the electrostatic capacitance of the variable capacitor 13 .

The rotating shaft body 181 has a linear shape extending along the rotating shaft C. As shown in FIG. The rotary shaft 181 is configured so that one end thereof extends from the front wall 19c of the container 19 to the outside. A front wall 19c of the container 19 is rotatably supported by a sealing member S2 such as an O-ring. Here, the front wall is supported at two points by two O-rings. The other end of the rotating shaft 181 is rotatably in contact with a positioning recess 191 provided on the inner surface of the container 19 .

The rotary shaft 181 has a portion 181x that supports the capacitance changing portion 18A and is made of a conductive material such as metal, and a portion 181y that extends out from the container 19 is made of an insulating material such as resin. there is

The capacitance changing portion 18A includes a first movable metal plate 182 supported by the rotary shaft 181 and facing the first fixed electrode 16, and a second movable metal plate 182 supported by the rotary shaft 181 and facing the second fixed electrode 17. 2 movable metal plates 183 .

A plurality of first movable metal plates 182 are provided corresponding to one or more first fixed metal plates 161 . The first movable metal plates 182 have the same shape. A plurality of second movable metal plates 183 are provided corresponding to one or more second fixed metal plates 171 . The second movable metal plates 183 have the same shape. These movable metal plates 182 and 183 are provided along the rotation axis C at approximately equal intervals. Further, in this embodiment, the movable metal plates 182 and 183 are sandwiched between the fixed metal plates 161 and 171 . Although six fixed metal plates 161 and 171 and two movable metal plates 182 and 183 are shown in FIG. 3, the present invention is not limited to this. A gap between the movable metal plates 182 and 183 and the fixed metal plates 161 and 171 is, for example, 1 mm.

As shown in FIG. 4, the first movable metal plate 182 and the second movable metal plate 183 are provided at symmetrical positions with respect to the rotation axis C and have the same shape. Specifically, as shown in FIG. 6, each of the movable metal plates 182 and 183 has a fan shape that expands radially outward from the rotation axis C in plan view. In this embodiment, it is fan-shaped with a central angle of 90 degrees.

Therefore, as shown in FIGS. 3 and 7, the variable capacitor 13 of this embodiment changes the electrostatic capacitance of the variable capacitor 13 between the fixed electrodes 16 and 17 regardless of the movement of the capacitance changing section 18A. It further has a capacity holding section 18B that maintains the capacity above a certain level.

The capacitance holding portion 18B is supported by a rotating shaft 181 and is configured to move while maintaining a certain or more facing area with the fixed electrodes 16 and 17. Specifically, the rotating shaft 181 It has a third movable metal plate 184 supported to face the first fixed electrode 16 and the second fixed electrode 17 .

A plurality of third movable metal plates 184 are provided corresponding to one or more first fixed metal plates 161 . FIG. 3 shows a configuration in which three third movable metal plates 184 are provided below the first movable metal plate 182 and the second movable metal plate 183, but the number of third movable metal plates 184 is and arrangement are not limited to this. A gap between the third movable metal plate 184 and the fixed metal plates 161 and 171 is, for example, 1 mm.

The third movable metal plates 184 have the same shape here, and are circular in plan view. In other words, the third movable metal plate 184 is a disk-shaped plate that moves while keeping the facing area between the first fixed metal plate 161 and the second fixed metal plate 171 constant without increasing or decreasing.

By rotating the movable electrode 18 in the variable capacitor 13 configured as described above, the facing area (first facing area) of the first fixed metal plate 161 and the first movable metal plate 182 is changed as shown in FIG. A1) changes, and the opposing area (second opposing area A2) between the second fixed metal plate 171 and the second movable metal plate 183 changes. Although the third fixed metal plate 184 is omitted in FIG. 8 for convenience of explanation, the third fixed metal plate 184 can be fixed to the first fixed metal plate 184 regardless of the rotation angle θ of the movable electrode 18 . It rotates while keeping the facing area between the metal plate 161 and the second fixed metal plate 171 constant.

In this embodiment, the first facing area A1 and the second facing area A2 change in the same manner. Further, the tip sides 161b and 171b of the fixed metal plates 161 and 171 on the rotation axis C side are arc-shaped, and by rotating the movable electrode 18, the first facing area A1 and the second facing area A2 , changes in proportion to the rotation angle θ of the movable electrode 18 .

In the above configuration, when the coolant CL flows from the introduction port P1 of the container 19, the inside of the container 19 is filled with the coolant CL. At this time, the space between the first fixed metal plate 161 and the first movable metal plate 182 and the space between the first fixed metal plate 161 and the third movable metal plate 184 are filled with the coolant CL. A space between the second fixed metal plate 171 and the second movable metal plate 183 and a space between the second fixed metal plate 171 and the third movable metal plate 184 are filled with the coolant CL. Thereby, the coolant CL becomes the dielectric of the first capacitor and the dielectric of the second capacitor. In this embodiment, the capacitance of the first capacitor and the capacitance of the second capacitor are the same. Also, the first capacitor and the second capacitor configured in this manner are connected in series, and the capacitance of the variable capacitor 13 is equal to the capacitance of the first capacitor (or the second capacitor). be halved.

Here, in this embodiment, the facing direction of the first fixed electrode 16 and the second fixed electrode 17 and the movable electrode 18 is configured to be perpendicular to the facing direction of the inlet port P1 and the outlet port P2. . That is, the fixed metal plates 161 and 171 and the movable metal plates 182 and 183 are provided along the facing direction of the inlet port P1 and the outlet port P2. This configuration makes it easier for the coolant CL to flow through the inside of the container 19 . As a result, replacement of the coolant CL in the container 19 is facilitated, and cooling of the variable capacitor 13 can be efficiently performed. In addition, the coolant CL that has flowed in from the introduction port P1 tends to flow between the fixed metal plates 161 and 171 and the movable metal plates 182 and 183, and flows out from between the fixed metal plates 161 and 171 and the movable metal plates 182 and 183. Cheap. As a result, replacement of the cooling liquid between the fixed metal plates 161 and 171 and the movable metal plates 182 and 183 is facilitated, and the temperature change of the cooling liquid CL serving as the dielectric is suppressed. This makes it easier to keep the capacitance of the variable capacitor 13 constant. Furthermore, air bubbles are less likely to stay between the fixed metal plates 161 and 171 and the movable metal plates 182 and 183 .

<Effects of this embodiment>
According to the plasma processing apparatus 100 of the present embodiment configured as described above, the antenna conductor 3 can be cooled by the cooling liquid CL, so that the plasma P can be stably generated. In addition, since the dielectric of the variable capacitor 13 is composed of the coolant CL flowing through the antenna conductor 3, the variable capacitor 13 can be cooled while suppressing unexpected fluctuations in its capacitance.

In addition, since the movable electrode 18 has the capacitance holding portion 18B that keeps the capacitance of the variable capacitor 13 above a certain level, the amount of change in reactance when the capacitance is changed by the capacitance changing portion 18A is reduced. It is possible to adjust the reactance stably. Here, the graph shown in FIG. 9 shows the relationship between the reactance of the variable capacitor 13 of this embodiment, the rotation angle θ of the movable electrode 18, and the capacitance of the variable capacitor 13. As shown in FIG. As can be seen from this graph, according to the variable capacitor 13 of the present embodiment, the amount of change in the reactance of the variable capacitor 13 in the low angle region of the rotation angle θ of the movable electrode 18 is greater than that of the conventional configuration (FIG. 12). is small, and it can be seen that it is easy to adjust the reactance in the low-angle region.

Moreover, since the capacitance holding unit 18B keeps the capacitance of the variable capacitor 13 at a certain level or more, the reactance of the variable capacitor 13 can be made at a certain level or more, and the antenna conductor 3 and the antenna conductor 3 can be connected without additionally connecting another capacitor. can be adjusted, and complication of connection with the antenna conductor 3 and enlargement of the device can be avoided.

In addition, since the third movable metal plate 184 has a circular shape in a plan view, the capacitance held by the capacitance holding portion 18B can be kept constant without fluctuation, and the reactance of the variable capacitor 13 can be accurately controlled. can be adjusted well.

In this embodiment, since it is not necessary to connect external circuit elements such as the antenna conductor 3 and grounding to the movable electrode 18, a slider (brush) is used to bring the movable electrode 18 into contact with external circuit elements. Therefore, it is possible to eliminate the need for a connector that uses a slider, and to reduce connection failure caused by a connector that uses a slider.

Furthermore, in this embodiment, since the first fixed electrode 16 and the second fixed electrode 17 are provided at different positions around the rotation axis C, it is possible to make the dimension in the axial direction of the rotation axis C compact. can.

Moreover, in this embodiment, each fixed electrode 16, 17 has a plurality of fixed metal plates 161, 171, and the movable electrode has a plurality of movable metal plates 182, 183, so that the fixed metal plates 161, 171 and the movable The maximum facing area between the electrodes can be increased without increasing the area of the metal plates 182 and 183 .

<Other Modified Embodiments>
It should be noted that the present invention is not limited to the above embodiments.

In the above-described embodiment, two first and second movable metal plates and three third movable metal plates were used, but the number of movable metal plates is not limited to this. At least one movable metal plate is sufficient.

Further, in the above embodiment, the third movable metal plate is provided below the first movable metal plate and the second movable metal plate, but the arrangement of each movable metal plate is not limited to this. A third movable metal plate may be provided above the first movable metal plate and the second movable metal plate, or as shown in FIG. , and the third movable metal plate may be alternately provided along the rotation axis.

Further, although each of the third movable metal plates in the above embodiment has a disk shape, it is sufficient if the entire third movable metal plate has a circular shape in plan view. Although it is not, it may be a circular disk shape or the like. In addition, in FIG. 11, description of the 1st movable metal plate and the 2nd movable metal plate is abbreviate|omitted for convenience of explanation.

In addition, the third movable metal plate is not limited to having a circular shape in plan view, but may have a rectangular shape, polygonal shape, comma-shaped shape, etc. Any shape can be used as long as it can move.

In addition, in the above embodiment, the movable electrode rotates around the rotation axis, but the movable electrode may slide in one direction. Here, as a configuration in which the movable electrode slides, the movable electrode may slide in a direction orthogonal to the direction in which it faces the fixed electrode to change the facing area. The facing distance may be changed by sliding along the direction.

Further, the shape of the fixed metal plate is not limited to the above embodiment, and various shapes can be used.

Furthermore, although the variable capacitor is provided between the antenna conductors adjacent to each other in the above embodiment, it may be provided between the antenna conductor and the ground. In this case, the first fixed electrode is electrically connected to the antenna conductor and the second fixed electrode is grounded.

Moreover, although the antenna conductor has a straight shape in the above embodiment, it may have a curved or bent shape. In this case, the metal pipe may have a curved or bent shape, or the insulating pipe may have a curved or bent shape.

In addition, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications are possible without departing from the spirit of the present invention.

REFERENCE SIGNS LIST 100 Plasma processing apparatus W Substrate P Inductively coupled plasma 2 Vacuum container 3 Antenna conductor 3 S Flow path CL Cooling liquid 13 Variable capacitor 16 First fixed electrode 161 Fixed metal plate 17 Second fixed electrode 171 Fixed metal plate 18 Movable electrode 18A Capacitance changing unit 18B Capacitance holding Section C Rotation shaft 182 First movable metal plate 183 Second movable metal plate 184 Third movable metal plate 161a, 171a Shrinking edge sides 161b, 171b . . . Tip side 19 .. Container P1 .. Introduction port P2 .

Claims (4)

A plasma processing apparatus for generating plasma in a vacuum vessel and processing a substrate using the plasma,
an antenna conductor through which a high frequency current is passed to generate a plasma;
a variable capacitor electrically connected to the antenna conductor;
The antenna conductor has a flow path in which a cooling liquid flows,
the dielectric of the variable capacitor is composed of a coolant flowing through the antenna conductor,
The variable capacitor is
a fixed electrode electrically connected to the antenna conductor;
a movable electrode forming a capacitor with the fixed electrode;
The movable electrode is
a capacitance changing unit that moves so as to change the area facing the fixed electrode to change the capacitance of the variable capacitor;
a capacitance holding unit that maintains the capacitance of the variable capacitor at a certain level or more between itself and the fixed electrode, regardless of the movement of the capacity changing part, and moves while holding the facing area with the fixed electrode at a certain level or more; A plasma processing apparatus. 2. The plasma processing apparatus according to claim 1, wherein said capacitance holding unit has one or more metal plates which are circular as a whole in plan view. 3. The plasma processing apparatus according to claim 2, wherein each of the plurality of metal plates forming said capacitance holding portion is disc-shaped. The variable capacitor has a second fixed electrode electrically connected to an antenna conductor different from the antenna conductor or grounded,
4. The capacity changing section has a movable electrode forming a first capacitor with the fixed electrode and forming a second capacitor with the second fixed electrode. The plasma processing apparatus according to any one of .

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