KR101522892B1 - Plasma generating device and apparatus for treating substrate comprising the same - Google Patents

Abstract

The present invention relates to an apparatus for treating a substrate. According to the present invention, the apparatus for treating the substrate comprises: a process chamber; a support unit supporting the substrate in the process chamber; a gas supply unit supplying process gas in the process chamber; and a plasma generating unit generating plasma from process gas provided in the process chamber, wherein the plasma generating unit comprises: a high frequency power supply; a first antenna connected with the high frequency power supply through a first line; a second antenna connected with the high frequency power supply through a second line diverging from the first line in a branch point, and provided in parallel with the first antenna; and a variable capacitor installed in series with the first antenna in the first line between the branch point and the first antenna.

Description

TECHNICAL FIELD [0001] The present invention relates to a plasma generating unit and a substrate processing apparatus including the plasma generating unit.

The present invention relates to a plasma generating unit and a substrate processing apparatus including the plasma generating unit.

The semiconductor manufacturing process may include processing the substrate using plasma. For example, an etching process during a semiconductor manufacturing process can remove a thin film on a substrate using a plasma.

In order to use the plasma in the substrate processing process, a plasma generating unit capable of generating plasma in the process chamber is mounted. The plasma generating unit is classified into a capacitively coupled plasma (CCP) type and an inductively coupled plasma (ICP) type according to a plasma generation method.

The source of the CCP type is arranged so that two electrodes are facing each other in the chamber, and an RF signal is applied to either or both electrodes to generate an electric field in the chamber to generate plasma. On the other hand, an ICP-type source generates plasma by introducing one or more coils into a chamber and applying an RF signal to the coils to induce an electromagnetic field in the chamber.

When two or more coils are installed in the chamber and two or more coils are powered from one RF power source, a power divider may be provided between the RF power source and the coils. The power distributor distributes power supplied from the RF power source at a predetermined ratio and supplies the divided power to each coil. However, the conventional power divider has a problem that the controllable power distribution range is very limited.

It is an object of the present invention to provide a plasma generating unit and a substrate processing apparatus including the same that can control the amount of power supplied to each coil over a wide range.

The problems to be solved by the present invention are not limited to the above-mentioned problems, and the problems not mentioned can be clearly understood by those skilled in the art from the description and the accompanying drawings will be.

The present invention provides a substrate processing apparatus.

A substrate processing apparatus according to an embodiment of the present invention includes a process chamber, a support unit for supporting the substrate in the process chamber, a gas supply unit for supplying the process gas in the process chamber, And a plasma generating unit for generating a plasma from the gas, wherein the plasma generating unit comprises: a high frequency power source; a first antenna connected to the high frequency power source through a first line; A second antenna connected to the high frequency power source and provided in parallel with the first antenna, and a variable capacitor provided in series with the first antenna in the first line between the branch point and the first antenna.

The plasma generating unit may further include a fixed capacitor connected in series with the second antenna to the second line between the branch point and the second antenna.

The plasma generating unit may further include a first capacitor provided on a ground line connected to the first antenna.

The plasma generating unit may further include a second capacitor provided on a ground line connected to the second antenna.

The first antenna and the second antenna may be provided in a ring shape, and the radius of the first antenna may be smaller than the radius of the second antenna.

The first antenna and the second antenna may be disposed on top of the process chamber.

The first antenna and the second antenna may be disposed on the side of the process chamber.

Either the first antenna or the second antenna may be disposed on the upper portion of the process chamber, and the other may be disposed on the side of the process chamber.

Further, the present invention provides a plasma generating apparatus.

A plasma generator according to another embodiment of the present invention includes a high frequency power source for generating a high frequency signal, a first antenna connected to the high frequency power source through a first line, and a second antenna connected to the high frequency power source via a second line, A second antenna connected to the high frequency power source and provided in parallel with the first antenna, and a variable capacitor provided in series with the first antenna in the first line between the branch point and the first antenna.

The plasma generator may further include a fixed capacitor connected in series with the second antenna to the second line between the branch point and the second antenna.

The plasma generator may further include a first capacitor disposed on a ground line connected to the first antenna.

The plasma generator may further include a second capacitor provided on a ground line connected to the second antenna.

According to the embodiment of the present invention, the amount of electric power supplied to each coil and the ratio thereof can be controlled over a wide range.

The effects of the present invention are not limited to the above-mentioned effects, and the effects not mentioned can be clearly understood by those skilled in the art from the present specification and attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating a substrate processing apparatus according to an embodiment of the present invention. FIG.
2 is a diagram illustrating an exemplary plasma generating unit according to an embodiment of the present invention.
3 is a diagram illustrating a configuration of a power divider according to an embodiment of the present invention.
4 is a diagram illustrating a configuration of a power divider according to another embodiment of the present invention.
5 is a diagram illustrating a configuration of a power divider according to another embodiment of the present invention.

The embodiments of the present invention can be modified into various forms and the scope of the present invention should not be interpreted as being limited by the embodiments described below. The present embodiments are provided to enable those skilled in the art to more fully understand the present invention. Accordingly, the shapes of the components and the like in the drawings are exaggerated in order to emphasize a clearer description.

In an embodiment of the present invention, a substrate processing apparatus for etching a substrate using plasma will be described. However, the present invention is not limited thereto, but is applicable to various kinds of apparatuses for heating a substrate placed thereon.

FIG. 1 is a view exemplarily showing a substrate processing apparatus 10 according to an embodiment of the present invention.

Referring to Fig. 1, a substrate processing apparatus 10 processes a substrate W using a plasma. For example, the substrate processing apparatus 10 may perform an etching process on the substrate W. [ The substrate processing apparatus 10 may include a process chamber 100, a support unit 200, a gas supply unit 300, a plasma generation unit 400, and a baffle unit 500.

The process chamber 100 provides a space in which the substrate processing process is performed. The process chamber 100 includes a housing 110, a seal cover 120, and a liner 130.

The housing 110 has a space whose top surface is open inside. The inner space of the housing 110 is provided to the processing space where the substrate processing process is performed. The housing 110 is made of a metal material. The housing 110 may be made of aluminum. The housing 110 may be grounded. An exhaust hole 102 is formed in the bottom surface of the housing 110. The exhaust hole 102 is connected to the exhaust line 151. The reaction by-products generated in the process and the gas staying in the inner space of the housing can be discharged to the outside through the exhaust line 151. The inside of the housing 110 is reduced in pressure to a predetermined pressure by the exhaust process.

The sealing cover 120 covers the open upper surface of the housing 110. The sealing cover 120 is provided in a plate shape to seal the inner space of the housing 110. The sealing cover 120 may include a dielectric substance window.

The liner 130 is provided inside the housing 110. The liner 130 is formed inside the space where the upper surface and the lower surface are opened. The liner 130 may be provided in a cylindrical shape. The liner 130 may have a radius corresponding to the inner surface of the housing 110. The liner 130 is provided along the inner surface of the housing 110. At the upper end of the liner 130, a support ring 131 is formed. The support ring 131 is provided in the form of a ring and projects outwardly of the liner 130 along the periphery of the liner 130. The support ring 131 rests on the top of the housing 110 and supports the liner 130. The liner 130 may be provided in the same material as the housing 110. That is, the liner 130 may be made of aluminum. The liner 130 protects the inside surface of the housing 110. An arc discharge may be generated in the chamber 100 during the process gas excitation. Arc discharge damages peripheral devices. The liner 130 protects the inner surface of the housing 110 to prevent the inner surface of the housing 110 from being damaged by the arc discharge. Also, impurities generated during the substrate processing process are prevented from being deposited on the inner wall of the housing 110. The liner 130 is less expensive than the housing 110 and is easier to replace. Thus, if the liner 130 is damaged by an arc discharge, the operator can replace the new liner 130.

The substrate supporting unit 200 is located inside the housing 110. The substrate supporting unit 200 supports the substrate W. The substrate supporting unit 200 may include an electrostatic chuck 210 for attracting the substrate W using an electrostatic force. Alternatively, the substrate support unit 200 may support the substrate W in a variety of ways, such as mechanical clamping. Hereinafter, the supporting unit 200 including the electrostatic chuck 210 will be described.

The supporting unit 200 includes an electrostatic chuck 210, an insulating plate 250 and a lower cover 270. The support unit 200 may be positioned within the chamber 100 and spaced upwardly from the bottom surface of the housing 110.

The electrostatic chuck 210 includes a dielectric plate 220, electrodes 223, a heater 225, a support plate 230, and a focus ring 240.

The dielectric plate 220 is located at the upper end of the electrostatic chuck 210. The dielectric plate 220 is provided as a disk-shaped dielectric substance. A substrate W is placed on the upper surface of the dielectric plate 220. The upper surface of the dielectric plate 220 has a smaller radius than the substrate W. [ Therefore, the edge region of the substrate W is located outside the dielectric plate 220. A first supply passage 221 is formed in the dielectric plate 220. The first supply passage 221 is provided from the upper surface to the lower surface of the dielectric plate 210. A plurality of first supply passages 221 are spaced apart from each other and are provided as passages through which the heat transfer medium is supplied to the bottom surface of the substrate W.

A lower electrode 223 and a heater 225 are buried in the dielectric plate 220. The lower electrode 223 is located above the heater 225. The lower electrode 223 is electrically connected to the first lower power source 223a. The first lower power source 223a includes a DC power source. A switch 223b is provided between the lower electrode 223 and the first lower power source 223a. The lower electrode 223 may be electrically connected to the first lower power source 223a by turning on / off the switch 223b. When the switch 223b is turned on, a direct current is applied to the lower electrode 223. An electrostatic force is applied between the lower electrode 223 and the substrate W by the current applied to the lower electrode 223 and the substrate W is attracted to the dielectric plate 220 by the electrostatic force.

The heater 225 is electrically connected to the second lower power source 225a. The heater 225 generates heat by resisting the current applied from the second lower power supply 225a. The generated heat is transferred to the substrate W through the dielectric plate 220. The substrate W is maintained at a predetermined temperature by the heat generated in the heater 225. The heater 225 includes a helical coil.

A support plate 230 is positioned below the dielectric plate 220. The bottom surface of the dielectric plate 220 and the top surface of the support plate 230 may be adhered by an adhesive 236. [ The support plate 230 may be made of aluminum. The upper surface of the support plate 230 may be stepped so that the central region is positioned higher than the edge region. The upper surface central region of the support plate 230 has an area corresponding to the bottom surface of the dielectric plate 220 and is bonded to the bottom surface of the dielectric plate 220. A first circulation channel 231, a second circulation channel 232, and a second supply channel 233 are formed in the support plate 230.

The first circulation channel 231 is provided as a passage through which the heat transfer medium circulates. The first circulation flow path 231 may be formed in a spiral shape inside the support plate 230. Alternatively, the first circulation flow path 231 may be arranged so that the ring-shaped flow paths having different radii have the same center. Each of the first circulation flow paths 231 can communicate with each other. The first circulation flow path 231 is formed at the same height.

The second circulation flow passage 232 is provided as a passage through which the cooling fluid circulates. The second circulation channel 232 may be formed in a spiral shape inside the support plate 230. Further, the second circulation flow path 232 may be arranged so that the ring-shaped flow paths having different radii have the same center. Each of the second circulation flow paths 232 can communicate with each other. The second circulation channel 232 may have a larger cross-sectional area than the first circulation channel 231. The second circulation flow path 232 is formed at the same height. The second circulation flow passage 232 may be positioned below the first circulation flow passage 231.

The second supply passage 233 extends upward from the first circulation passage 231 and is provided on the upper surface of the support plate 230. The second supply passage 243 is provided in a number corresponding to the first supply passage 221 and connects the first circulation passage 231 to the first supply passage 221.

The first circulation channel 231 is connected to the heat transfer medium storage unit 231a through the heat transfer medium supply line 231b. The heat transfer medium is stored in the heat transfer medium storage unit 231a. The heat transfer medium includes an inert gas. According to an embodiment, the heat transfer medium comprises helium (He) gas. The helium gas is supplied to the first circulation channel 231 through the supply line 231b and is supplied to the bottom surface of the substrate W through the second supply channel 233 and the first supply channel 221 in sequence. The helium gas serves as a medium through which the heat transferred from the plasma to the substrate W is transferred to the electrostatic chuck 210.

The second circulation channel 232 is connected to the cooling fluid storage 232a through the cooling fluid supply line 232c. The cooling fluid is stored in the cooling fluid storage part 232a. A cooler 232b may be provided in the cooling fluid storage portion 232a. The cooler 232b cools the cooling fluid to a predetermined temperature. Alternatively, the cooler 232b may be installed on the cooling fluid supply line 232c. The cooling fluid supplied to the second circulation channel 232 through the cooling fluid supply line 232c circulates along the second circulation channel 232 to cool the support plate 230. The support plate 230 cools the dielectric plate 220 and the substrate W together while keeping the substrate W at a predetermined temperature.

The focus ring 240 is disposed in the edge region of the electrostatic chuck 210. The focus ring 240 has a ring shape and is disposed along the periphery of the dielectric plate 220. The upper surface of the focus ring 240 may be stepped so that the outer portion 240a is higher than the inner portion 240b. The upper surface inner side portion 240b of the focus ring 240 is positioned at the same height as the upper surface of the dielectric plate 220. [ The upper surface inner side portion 240b of the focus ring 240 supports an edge region of the substrate W positioned outside the dielectric plate 220. [ The outer side portion 240a of the focus ring 240 is provided so as to surround the edge region of the substrate W. [ The focus ring 240 allows the plasma to be concentrated within the chamber 100 in a region facing the substrate W. [

An insulating plate 250 is disposed under the support plate 230. The insulating plate 250 is provided in a cross-sectional area corresponding to the support plate 230. [ The insulating plate 250 is positioned between the support plate 230 and the lower cover 270. The insulating plate 250 is made of an insulating material and electrically insulates the supporting plate 230 and the lower cover 270.

The lower cover 270 is located at the lower end of the substrate supporting unit 200. The lower cover 270 is spaced upwardly from the bottom surface of the housing 110. The lower cover 270 has a space in which an upper surface is opened. The upper surface of the lower cover 270 is covered with an insulating plate 250. Thus, the outer radius of the cross section of the lower cover 270 can be provided with a length equal to the outer radius of the insulating plate 250. A lift pin module (not shown) for moving the substrate W to be transferred from an external carrying member to the electrostatic chuck 210 may be positioned in the inner space of the lower cover 270.

The lower cover 270 has a connecting member 273. The connecting member 273 connects the outer side surface of the lower cover 270 and the inner side wall of the housing 110. A plurality of connecting members 273 may be provided on the outer surface of the lower cover 270 at regular intervals. The connecting member 273 supports the substrate supporting unit 200 inside the chamber 100. The connecting member 273 is connected to the inner wall of the housing 110 so that the lower cover 270 is electrically grounded. A first power supply line 223c connected to the first lower power supply 223a, a second power supply line 225c connected to the second lower power supply 225a, a heat transfer medium supply line 233b connected to the heat transfer medium storage 231a And the cooling fluid supply line 232c connected to the cooling fluid reservoir 232a extend into the lower cover 270 through the inner space of the connection member 273. [

The gas supply unit 300 supplies the process gas into the chamber 100. The gas supply unit 300 includes a gas supply nozzle 310, a gas supply line 320, and a gas storage unit 330. The gas supply nozzle 310 is installed at the center of the sealing cover 120. A jetting port is formed on the bottom surface of the gas supply nozzle 310. The injection port is located at the bottom of the closed cover 120 and supplies the process gas to the processing space inside the chamber 100. The gas supply line 320 connects the gas supply nozzle 310 and the gas storage unit 330. The gas supply line 320 supplies the process gas stored in the gas storage unit 330 to the gas supply nozzle 310. A valve 321 is installed in the gas supply line 320. The valve 321 opens and closes the gas supply line 320 and regulates the flow rate of the process gas supplied through the gas supply line 320.

The plasma generating unit 400 excites the process gas in the chamber 100 into a plasma state. According to one embodiment of the present invention, the plasma generating unit 400 may be configured as an ICP type.

The plasma generating unit 400 may include a high frequency power source 420, a first antenna 411, a second antenna 413, and a power divider 430. The high frequency power source 420 supplies a high frequency signal. As an example, the high frequency power source 420 may be an RF power source 420. The RF power source 420 supplies RF power. Hereinafter, a case where the high frequency power source 420 is provided as the RF power source 420 will be described. The first antenna 411 is connected to the high frequency power source 420 through the first line L1. The second antenna 413 is connected to the high frequency power source 420 through the second line L2. The second line (L2) branches at the branch point (P) of the first line (L1). The first antenna 411 and the second antenna 413 may be provided as a plurality of circuit winding coils, respectively. The first antenna 411 and the second antenna 413 are electrically connected to the RF power source 420 and receive RF power. The power distributor 430 distributes the power supplied from the RF power source 420 to each antenna.

The first antenna 411 and the second antenna 413 may be disposed at positions opposite to the substrate W. [ For example, the first antenna 411 and the second antenna 413 may be installed on top of the process chamber 100. The first antenna 411 and the second antenna 413 may be provided in a ring shape. At this time, the radius of the first antenna 411 may be smaller than the radius of the second antenna 413. In this case, the first antenna 411 may be located in the upper portion of the process chamber 100, and the second antenna 413 may be located outside the upper portion of the process chamber 100.

According to an embodiment, the first and second antennas 411 and 413 may be disposed on the side of the process chamber 100. Either one of the first and second antennas 411 and 413 may be disposed on top of the process chamber 100 and the other may be disposed on the side of the process chamber 100. [ The position of the coils is not limited as long as a plurality of antennas generate plasma in the process chamber 100.

The first antenna 411 and the second antenna 413 may receive RF power from the RF power source 420 to induce a time-varying electromagnetic field in the chamber, and thus the process gas supplied to the process chamber 100 may be plasma- It can be here.

The baffle unit 500 is positioned between the inner wall of the housing 110 and the substrate support unit 200. The baffle unit 500 includes a baffle in which a through hole is formed. The baffle is provided in an annular ring shape. The process gas provided in the housing 110 is exhausted to the exhaust hole 102 through the through holes of the baffle. The flow of the process gas can be controlled according to the shape of the baffle and the shape of the through holes.

FIG. 2 is a view exemplarily showing a plasma generating unit 400 according to an embodiment of the present invention.

2, the plasma generating unit 400 may include an RF power source 420, a first antenna 411, a second antenna 413, and a power divider 430.

The RF power source 420 may generate an RF signal. According to one embodiment, the RF power source 420 may generate sinusoids having a predetermined frequency. However, the waveform of the signal generated by the RF power source 420 is not limited to this, and may have various waveforms such as a sawtooth wave and a triangle wave.

The first antenna 411 and the second antenna 413 receive an RF signal from the RF power source 420 and induce an electromagnetic field to generate plasma. The plasma generating unit 400 shown in FIG. 2 includes a total of two antennas 411 and 413, but the number of the antennas is not limited thereto and may be three or more according to the embodiment.

The power divider 430 is installed between the RF power source 420 and the plurality of antennas 411 and 413 to distribute the power supplied from the RF power source 420 to each antenna.

The plasma generating unit 400 may further include an impedance matcher 440. The impedance matcher 440 is connected to the output terminal of the RF power source 420 to match the output impedance of the power source with the input impedance of the load.

3 is a diagram illustrating a configuration of a power divider 430 according to an embodiment of the present invention.

The power divider 430 according to an embodiment of the present invention may include a variable capacitor 431 connected in series to any one of the first antenna 411 and the second antenna 413. [ For example, the variable capacitor 431 may be connected in series with the first antenna 411. The variable capacitor 431 is provided on the first line L1. For example, the variable capacitor 431 may be provided on the first line L1 between the branch point P and the first antenna 411, as shown in FIG. At this time, the currents of the respective antennas 411 and 413 can be varied by using the single variable capacitor 431, and the plasma source can be stabilized by reducing the resonance point. Alternatively, the variable capacitor 431 may be connected in series with the second antenna 413.

According to this embodiment, since the variable capacitor 431 is connected in series to the first antenna 411, the magnitude of the impedance Z1 viewed from the input terminal of the variable capacitor 431 varies depending on the value of the variable capacitor 431. [ Accordingly, the magnitude of the impedance Z2 viewed from the input terminal of the second antenna 413 changes according to the value of Z1.

In this way, when the impedance of one of the plurality of antennas is designed to be large while the impedance of the other antenna is designed to be small, the amount of power supplied to each antenna and the ratio thereof can be more easily controlled.

4 is a diagram illustrating a configuration of a power divider 430 according to another embodiment of the present invention.

The power divider 430 according to another embodiment of the present invention includes a variable capacitor 431 connected in series to the first antenna 411 and a fixed capacitor 433 connected in series to the second antenna 413 . 4, a fixed capacitor C may be provided on the second line L2 between the branch point P and the second antenna 413. When a capacitor is connected to each of the first antenna 411 and the second antenna 413 and one of them is provided to the variable capacitor 431, the respective antennas 411 and 413 can be individually resonated, . Therefore, current control to each of the antennas 411 and 413 is possible. Alternatively, the fixed capacitor 433 may be connected in series with the first antenna 411, and the variable capacitor 431 may be connected in series with the second antenna 413.

5 is a diagram illustrating an exemplary configuration of a power divider 430 according to another embodiment of the present invention.

The power divider 430 according to another embodiment of the present invention may include a variable capacitor 431, a first capacitor 433, and a second capacitor 435. The variable capacitor 431 is connected in series to the first antenna 411. For example, the variable capacitor 431 may be provided on the first line L1 between the branch point P and the first antenna 411. The first capacitor 433 is provided on the first line L1. Referring to FIG. 5, a first capacitor 433 is installed on a ground line to which the first antenna 411 is connected. And the second capacitor 435 is provided on the second line L2. Referring to FIG. 5, the second capacitor 435 is installed on the ground line to which the second antenna 413 is connected. At this time, each of the antennas 411 and 413 can resonate by connecting a capacitor in series between the antennas 411 and 413 and the ground. Therefore, after the antennas 411 and 413 are resonated to a wide range, the variable capacitor 431 can control the current entering each antenna 411 and 413.

The above-described variable elements receive a control signal from a controller (not shown), and the element value can be changed accordingly. The controller can control the characteristics of the plasma to be suitable for the process by adjusting the device value according to the process using the plasma.

According to the embodiment of the present invention described above, the load impedance viewed from the RF power source 420, that is, the first antenna 411 side impedance Z1 and the second antenna 413 side impedance Z2 can be implemented over a wider range.

As a result, the design of the first and second antennas 411 and 413 becomes easier, and further, the amount of power supplied to each coil and the ratio thereof can be more easily controlled.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

10: substrate processing apparatus
100: chamber
200: substrate holding unit
300: gas supply unit
400: Plasma generating unit
411: first coil
413: second coil
420: RF power source
430: Power distributor
431: variable inductor
432: Capacitor
433, 434: variable capacitor
500: Baffle unit

Claims (10)

In the substrate processing apparatus,
A process chamber;
A support unit for supporting the substrate in the process chamber;
A gas supply unit for supplying a process gas in the process chamber; And
And a plasma generation unit for generating a plasma from the process gas supplied into the process chamber,
The plasma generating unit includes:
High frequency power source;
A first antenna connected to the high frequency power source through a first line;
A second antenna connected to the high frequency power source through a second line branched from the first line at a branch point and provided in parallel with the first antenna;
A variable capacitor provided in series with the first antenna in the first line between the branch point and the first antenna;
A fixed capacitor connected in series with the second antenna to the second line between the branch point and the second antenna;
A first capacitor disposed in series with a first antenna on a ground line connected to the first antenna; And
A second capacitor connected in series with a second antenna on a ground line connected to the second antenna;
And the substrate processing apparatus.
delete delete delete The method according to claim 1,
Wherein the first antenna and the second antenna are provided in a ring shape, and the radius of the first antenna is smaller than the radius of the second antenna.
The method according to claim 1,
Wherein the first antenna and the second antenna are disposed on top of the process chamber.
A high frequency power source for generating a high frequency signal;
A first antenna connected to the high frequency power source through a first line;
A second antenna connected to the high frequency power source through a second line branched from the first line at a branch point and provided in parallel with the first antenna;
A variable capacitor provided in series with the first antenna in the first line between the branch point and the first antenna;
A fixed capacitor connected in series with the second antenna to the second line between the branch point and the second antenna;
A first capacitor disposed in series with a first antenna on a ground line connected to the first antenna; And
A second capacitor connected in series with a second antenna on a ground line connected to the second antenna;
And the substrate processing apparatus.
delete delete delete

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