Induction coil structure and inductively coupled plasma generating device

Abstract

To provide an inductively coupled plasma generator, in which capacitive coupling is reduced by the structure of an inductive coil and improved stability and efficiency can be achieved.SOLUTION: An inductively coupled plasma generator 100 includes: a dielectric tube 130 extending in a length direction; a first inductive coil structure 110, which is provided to enclose the dielectric tube 130 and produces inductively-coupled plasma in the dielectric tube 130; an RF power supply 140, which is configured to provide positive and negative powers having opposite phases, to respectively supply positive and negative powers of RF power 140 to both ends of the first inductive coil structure 110, and to change a driving frequency; a first main capacitor 121 provided between a positive output terminal of the RF power supply 140 and one end of the first inductive coil structure 110; and a second main capacitor 122 provided between a negative output terminal of the RF power supply 140 and the other end of the first inductive coil structure 110.SELECTED DRAWING: Figure 2A

Description

[Technical field]

[0001] The present invention relates to an inductively coupled plasma generator, and more particularly to an inductively coupled plasma generator having a voltage distribution structure in which a capacitor is inserted between a plurality of antennas. [Background technology]

[0002] Plasma is traditionally used in etching or deposition processes for substrates such as semiconductor wafers. Plasma is also used in new material synthesis, surface treatment, environmental purification, etc. Meanwhile, atmospheric pressure plasma is used in plasma scrubbers, cleaning, sterilization, skin beauty, etc.

[0003] A typical inductively coupled plasma uses an induction coil wound around a dielectric discharge tube, but the typical induction coil structure has low discharge stability and low plasma density.

[0004] The present invention provides a new induction coil structure capable of stably generating inductively coupled plasma at atmospheric pressure or at high pressures of several Torr or higher. Summary of the Invention [Problem to be solved by the invention]

[0005] It is an object of the present invention to provide an induction coil for generating inductively coupled plasma that suppresses charge-coupled components and improves discharge stability and efficiency.

[0006] A technical problem to be solved by the present invention is to provide an induction coil and a plasma generating device that suppresses a voltage rise caused by an increase in the number of turns of the induction coil.

[0007] SUMMARY OF THE PRESENT EMBODIMENT One technical problem to be solved by the present invention is to provide an induction coil that maximizes the number of turns per unit length and suppresses capacitive coupling. [Means for solving the problem]

[0008] An inductively coupled plasma generating apparatus according to an embodiment of the present invention includes a dielectric tube extending in a length direction, a first induction coil structure disposed to enclose the dielectric tube and generate inductively coupled plasma within the dielectric tube, an RF power source providing positive and negative outputs of opposite phases to each other and supplying positive and negative outputs of RF power to both ends of the first induction coil structure, respectively, and changing a driving frequency, a first main capacitor disposed between the positive output end of the RF power source and one end of the first induction coil structure, and a second main capacitor disposed between the negative output end of the RF power source and the other end of the first induction coil structure. The first induction coil structure includes induction coils connected in series to each other and disposed in different layers, each layer having at least one turn, and auxiliary capacitors disposed between adjacent induction coils to distribute a voltage applied to the induction coils.

[0009] In one embodiment of the present invention, each of the induction coils has the same first inductance L1, each of the auxiliary capacitors has the same first capacitance C1, and the driving frequency of the RF power source is controlled to match a resonant frequency of the first inductance L1 and the first capacitance C1 connected in series.

[0010] In one embodiment of the present invention, the first main capacitor and the second main capacitor each have the same second capacitance C2, and the second capacitance C2 is twice the first capacitance C1.

[0011] In one embodiment of the present invention, each of the induction coils is a 2-turn to 4-turn antenna.

[0012] In one embodiment of the present invention, the device further includes a second induction coil structure that is disposed to enclose the dielectric tube, is disposed apart from the first induction coil structure, has the same structure as the first induction coil structure, and generates inductively coupled plasma within the dielectric tube. One end of the second induction coil structure is connected to one end of the first induction coil structure, and the other end of the second induction coil structure is connected to the other end of the first induction coil structure, and the first induction coil structure and the second induction coil structure are connected in parallel to each other between the first main capacitor and the second main capacitor.

[0013] In one embodiment of the present invention, the induction coils constituting the first induction coil structure and the second induction coil structure each have the same first inductance L1, the auxiliary capacitors constituting the first induction coil structure and the second induction coil structure each have the same first capacitance C1, and the driving frequency of the RF power source is controlled to match a resonant frequency of the first inductance L1 and the first capacitance C1 connected in series.

[0014] In one embodiment of the present invention, the first main capacitor and the second main capacitor each have the same second capacitance C2, and the second capacitance C2 is four times the first capacitance C1.

[0015] In one embodiment of the present invention, one end of the first induction coil structure and one end of the second induction coil structure are disposed adjacent to each other, and one end of the first induction coil structure and one end of the second induction coil structure are connected to each other and to the first main capacitor.

[0016] In an embodiment of the present invention, each of the induction coils has a portion open in a first direction in a Cartesian coordinate system, the first arc portion having a first central angle, the first arc portion being disposed on an arrangement plane and having a certain first radius, a second arc portion having a second central angle less than the first central angle, the second arc portion being disposed on the arrangement plane and having a second radius greater than the first radius, and the first arc portion being disposed to have a central axis coincident with a central axis of the first arc portion, a first connecting portion being disposed on the arrangement plane, connected to one end of the first arc portion and extending in the first direction, a first arc connecting portion being disposed on the arrangement plane and having a “U” shape connecting the other end of the first arc portion and one end of the second arc portion, and a second connecting portion being disposed on the arrangement plane, connected to the other end of the second arc portion and extending in the first direction.

[0017] In one embodiment of the present invention, each of the induction coils has a portion that is open in a first direction in a Cartesian coordinate system, has a first central angle, is disposed on a placement plane, and has a certain first radius; a second arc portion that has a second central angle less than the first central angle, is disposed on the placement plane, has a second radius greater than the first radius, and is disposed to have the same central axis as the central axis of the first arc portion; and a third central angle less than the second central angle, is disposed on the placement plane, has a third radius greater than the second radius, and is disposed on the first arc portion. the third arc portion disposed to have the same central axis as the core shaft; a first connecting portion disposed on the arrangement plane, connected to one end of the first arc portion and extending in the first direction; a "U"-shaped first arc connecting portion disposed on the arrangement plane and connecting the other end of the first arc portion and one end of the second arc portion; a "U"-shaped second arc connecting portion disposed on the arrangement plane and connecting the other end of the second arc portion and one end of the third arc portion; and a second connecting portion disposed on the arrangement plane, connected to the other end of the third arc portion and extending in the first direction.

[0018] In one embodiment of the present invention, each of the induction coils has a portion that is open in a first direction in a Cartesian coordinate system, has a first central angle, is disposed on a placement plane, and has a certain first radius; a second arc portion that has a second central angle less than the first central angle, is disposed on the placement plane, has a second radius larger than the first radius, and is disposed to have the same central axis as the central axis of the first arc portion; a third arc portion that has a third central angle less than the second central angle, is disposed on the placement plane, has a third radius larger than the second radius, and is disposed to have the same central axis as the central axis of the first arc portion; and a fourth central angle less than the third central angle, is disposed on the placement plane, and has a fourth radius greater than the third radius. a fourth arc portion having a fourth radius and arranged to have the same central axis as a central axis of the first arc portion; a first connecting portion arranged on the arrangement plane, connected to one end of the first arc portion and extending in the first direction; a first arc connecting portion arranged on the arrangement plane and having a "U" shape connecting the other end of the first arc portion and one end of the second arc portion; a second arc connecting portion arranged on the arrangement plane and having a "U" shape connecting the other end of the second arc portion and one end of the third arc portion; a third arc connecting portion arranged on the arrangement plane and having a "U" shape connecting the other end of the third arc portion and one end of the fourth arc portion; and a second connecting portion arranged on the arrangement plane, connected to the other end of the fourth arc portion and extending in the first direction.

[0019] In one embodiment of the present invention, the first induction coil structure and the second induction coil structure are arranged in mirror symmetry above / below with respect to one point of the dielectric discharge tube, and current is distributed above / below from the center and then collected at both ends.

[0020] In one embodiment of the invention, the power input ends of the induction coils are arranged to maintain a constant azimuth angle with respect to each other.

[0021] In one embodiment of the invention, at least a portion of the induction coil is fixed in a ceramic mould.

[0022] In one embodiment of the invention, the device further comprises an insulating spacer in the form of a washer disposed between the induction coils to provide electrical insulation.

[0023] In one embodiment of the present invention, the induction coil includes a first induction coil and a fourth induction coil which are sequentially stacked, the auxiliary capacitor includes first to third auxiliary capacitors, the second induction coil is rotated 90 degrees counterclockwise in preparation for the first induction coil being disposed and aligned below the first induction coil, the third induction coil is rotated 90 degrees counterclockwise in preparation for the second induction coil being disposed and aligned below the second induction coil, and the fourth induction coil is rotated 90 degrees counterclockwise in preparation for the third induction coil being disposed. The first induction coil is rotated and disposed in alignment below the third induction coil, and one end of the first induction coil is connected to one end of the second induction coil through the first auxiliary capacitor, the other end of the second induction coil is connected to one end of the third induction coil through the second auxiliary capacitor, the other end of the third induction coil is connected to one end of the fourth induction coil through the third auxiliary capacitor, and the other end of the fourth induction coil is connected to the negative output terminal of the RF power source through the second main capacitor.

[0024] According to an embodiment of the present invention, a substrate processing apparatus includes a process chamber for processing a semiconductor substrate, and an inductively coupled plasma generator for providing active species to the process chamber by plasma. The inductively coupled plasma generator includes a dielectric tube extending in a length direction, a first induction coil structure arranged to enclose the dielectric tube and generate inductively coupled plasma within the dielectric tube, an RF power source providing positive and negative outputs of opposite phases to each other and supplying positive and negative outputs of RF power to both ends of the first induction coil structure, respectively, and changing a driving frequency, a first main capacitor arranged between the positive output end of the RF power source and one end of the first induction coil structure, and a second main capacitor arranged between the negative output end of the RF power source and the other end of the first induction coil structure. The first induction coil structure includes induction coils connected in series to each other and arranged in different layers, each layer having at least one turn, and auxiliary capacitors arranged between adjacent induction coils to distribute a voltage applied to the induction coils.

[0025] According to an embodiment of the present invention, an induction coil structure is disposed to enclose a dielectric tube and generates an inductively coupled plasma within the dielectric tube. The induction coil structure includes induction coils having the same structure, each of which is connected in series to each other and disposed in different layers, each of which has at least one turn, and auxiliary capacitors disposed between adjacent induction coils to distribute a voltage applied to the induction coils.

[0026] In one embodiment of the present invention, each of the induction coils has a portion that is open in a first direction in a Cartesian coordinate system, has a first central angle, is disposed on a placement plane, and has a certain first radius; a second arc portion that has a second central angle less than the first central angle, is disposed on the placement plane, has a second radius greater than the first radius, and is disposed to have the same central axis as the central axis of the first arc portion; and a third central angle less than the second central angle, is disposed on the placement plane, has a third radius greater than the second radius, and is disposed on the first arc portion. the third arc portion disposed to have the same central axis as the core shaft; a first connecting portion disposed on the arrangement plane, connected to one end of the first arc portion and extending in the first direction; a "U"-shaped first arc connecting portion disposed on the arrangement plane and connecting the other end of the first arc portion and one end of the second arc portion; a "U"-shaped second arc connecting portion disposed on the arrangement plane and connecting the other end of the second arc portion and one end of the third arc portion; and a second connecting portion disposed on the arrangement plane, connected to the other end of the third arc portion and extending in the first direction.

[0027] In one embodiment of the present invention, each of the induction coils has a portion that is open in a first direction in a Cartesian coordinate system, has a first central angle, is disposed on a placement plane, and has a certain first radius; a second arc portion that has a second central angle less than the first central angle, is disposed on the placement plane, has a second radius greater than the first radius, and is disposed to have the same central axis as the central axis of the first arc portion; a third arc portion that has a third central angle less than the second central angle, is disposed on the placement plane, has a third radius greater than the second radius, and is disposed to have the same central axis as the central axis of the first arc portion; and a fourth central angle less than the third central angle, is disposed on the placement plane, and has a fourth radius greater than the third radius. a fourth arc portion arranged to have the same central axis as the central axis of the first arc portion; a first connecting portion arranged on the arrangement plane, connected to one end of the first arc portion and extending in the first direction; a first arc connecting portion arranged on the arrangement plane and having a "U" shape connecting the other end of the first arc portion and one end of the second arc portion; a second arc connecting portion arranged on the arrangement plane and having a "U" shape connecting the other end of the second arc portion and one end of the third arc portion; a third arc connecting portion arranged on the arrangement plane and having a "U" shape connecting the other end of the third arc portion and one end of the fourth arc portion; and a second connecting portion arranged on the arrangement plane, connected to the other end of the fourth arc portion and extending in the first direction. Effect of the Invention

[0028] The plasma generating apparatus according to an embodiment of the present invention reduces capacitive coupling due to the structure of the induction coil, and provides stable and highly efficient inductively coupled plasma.

[0029] A plasma generating apparatus according to an embodiment of the present invention distributes voltage through auxiliary capacitors connected in series between induction coils constituting an induction coil structure, thereby reducing the maximum voltage applied overall.

[0030] In a plasma generating device according to one embodiment of the invention, each induction coil constituting an induction coil structure has the same potential at the point where it contacts the dielectric tube, thereby suppressing the generation of parasitic capacitors, improving discharge stability, and suppressing localized ion sputtering. [Brief description of the drawings]

[0031] [Figure 1] 1 is a conceptual diagram illustrating a semiconductor substrate processing apparatus according to an embodiment of the present invention; [Figure 2A] 1 is a conceptual diagram illustrating an inductively coupled plasma generating apparatus according to an embodiment of the present invention. [Figure 2B] FIG. 2B is a circuit diagram illustrating the inductively coupled plasma generating device of FIG. 2A. [Figure 2C] 2B is a diagram illustrating voltage distribution in the inductively coupled plasma generating apparatus of FIG. 2A. [Figure 2D] FIG. 2B is a plan view illustrating the inductively coupled plasma generation device of FIG. 2A. [Figure 2E] FIG. 2B is a plan view illustrating the induction coil of the inductively coupled plasma generation device of FIG. 2A. [Figure 3A] FIG. 4 is a conceptual diagram illustrating an inductively coupled plasma generating apparatus according to another embodiment of the present invention. [Figure 3B] FIG. 3B is a circuit diagram illustrating the inductively coupled plasma generating device of FIG. 3A. [Figure 3C] 3B is a diagram illustrating voltage distribution in an inductive coil structure of the inductively coupled plasma generating apparatus of FIG. 3A. [Figure 4A] FIG. 4 is a conceptual diagram illustrating an inductively coupled plasma generating apparatus according to still another embodiment of the present invention. [Figure 4B] FIG. 4B is a circuit diagram illustrating the inductively coupled plasma generating device of FIG. 4A. [Figure 4C] 4B is a diagram illustrating voltage distribution in an inductive coil structure of the inductively coupled plasma generating apparatus of FIG. 4A. [Figure 4D] FIG. 4B is a plan view illustrating the induction coil of the inductively coupled plasma generation device of FIG. 4A. [Figure 5A]FIG. 4 is a conceptual diagram illustrating an inductively coupled plasma generating apparatus according to still another embodiment of the present invention. [Figure 5B] FIG. 5B is a plan view illustrating the induction coil of the inductively coupled plasma generation device of FIG. 5A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] With an antenna arranged to encase the dielectric discharge tube, a high potential (3 kV or more) is applied inside the dielectric discharge tube under low pressure conditions (a pressure range of several tens of Torr or less where there is no fluid effect). In this case, plasma is generated inside the dielectric discharge tube. The surface of the dielectric discharge tube is heated by ion collisions. As a result, the dielectric discharge tube is heated to 1000 degrees Celsius or higher. The high heat modifies the surface of the dielectric discharge tube or generates perforations in the dielectric discharge tube.

[0033] The high potential applied to the antenna is affected by the inductance, frequency, and current of the antenna. Under high power conditions, the high potential applied to the antenna will always appear. Therefore, it is necessary to reduce the high potential generated on the antenna.

[0034] The present invention proposes a method for minimizing heating due to ion collisions by reducing the applied high voltage when such high power of several kilowatts or more is applied.

[0035] Inductively coupled plasma devices are used in semiconductor processing equipment, inductively coupled spectroscopy devices, ion beam generating devices, cleaning devices for inside deposition chambers, cleaning devices for exhaust ports of deposition chambers, plasma scrubbers for removing waste gases from semiconductor processing equipment, cleaning devices for cleaning process chambers of chemical vapor deposition equipment, and the like.

[0036] According to one embodiment of the present invention, an inductively coupled plasma generator is used as a remote plasma source to provide activated species to a semiconductor processing chamber.

[0037] The induction coil and plasma that generate inductively coupled plasma are modeled by a transformer circuit. Thus, inductively coupled plasma is called transformer coupled plasma. The induction coil operates with the primary coil of the transformer circuit, and the plasma operates with the secondary coil of the transformer circuit. A magnetic flux-restricting material such as a magnetic material is used to increase the magnetic coupling between the induction coil and the plasma. However, the magnetic flux-restricting material is difficult to apply to a cylindrical dielectric discharge vessel. Another method to increase the magnetic coupling between the induction coil and the plasma is to increase the inductance or number of turns of the induction coil. However, an increase in the inductance of the induction coil increases the impedance, making efficient power transfer difficult. In addition, an increase in the inductance of the induction coil increases the voltage applied to the induction coil, inducing a parasitic arc discharge. In addition, a high voltage applied to the induction coil induces a capacitive coupled discharge, and induces damage and heat damage due to ion bombardment of the dielectric discharge vessel.

[0038] According to an embodiment of the present invention, in order to reduce the voltage applied to the induction coil, a capacitor is disposed between the induction coils connected in series, and the entire voltage is distributed between the induction coil and the capacitor. Specifically, the induction coil is divided, an auxiliary capacitor is disposed between the divided induction coils, and main capacitors are disposed on both ends of the induction coil. As a result, the electrostatic field due to the screening effect is reduced, and the voltage applied to the induction coil is reduced according to a voltage distribution model. The divided induction coil and the auxiliary capacitor form a series resonant circuit, and the resonant frequency of the resonant circuit is the same as the driving frequency of the AC power source. As a result, stable impedance matching is performed when a low voltage is applied to the induction coil.

[0039] Inductively coupled plasma is usually formed using a driving frequency of several MHz at a pressure of several hundred milliTorr. However, such inductively coupled plasma has a small induction electric field strength, so it is difficult to perform atmospheric pressure discharge or discharge at a pressure of several Torr or more. Therefore, a sufficient induction electric field strength is required, and a separate means for initial discharge is required.

[0040] When an inductively coupled plasma discharge is performed by applying RF power to an induction coil that encases a dielectric tube, the inductively coupled plasma heats the dielectric tube, which can be damaged. Therefore, there is a structural limit to high-power inductively coupled plasma of tens of kWatts or more.

[0041] According to an embodiment of the present invention, in order to improve the efficiency or stability of the conventional inductively coupled plasma, 1) a laminated antenna (coil structure) that increases the strength of the induction electric field, 2) a capacitor connection structure for dividing the induction coil and reducing impedance between the divided induction coils, 3) a structure for connecting main capacitors to both ends of the induction coil to satisfy the overall resonance condition, and 4) a variable frequency AC power supply unit that improves the stability of the plasma in the induction coil are applied. As a result, it is possible to stably process a flow rate of tens to hundreds of liters per minute at a high pressure of several torr or more, which could not be achieved by the conventional inductively coupled plasma device. In addition, without requiring a separate electrode for initial discharge, the initial discharge is performed when the driving frequency of the AC power supply unit is not in the resonance condition. When the resonance condition is not met, a high voltage is applied to the induction coil to perform the initial discharge. Then, the driving frequency of the AC power supply is changed to the resonance condition to perform the main discharge.

[0042] In the following, the terms induction coil and antenna are used interchangeably to mean the same thing. In the case of an inductively coupled plasma (ICP) antenna, the strength of the induction electric field transferred to the plasma is proportional to the current and frequency of the induction coil, and is proportional to the square of the number of turns. Therefore, the more turns the induction coil (or antenna) has, the higher the electric field can be applied to the plasma. However, as the number of turns of the solenoid coil increases, the energy is distributed along the length of the dielectric discharge tube due to spatial constraints. Also, the high inductance (impedance) of the induction coil makes it difficult to transfer power from the RF generator to the induction coil (antenna).

[0043] Since the density of the electric field formed around the plasma must be increased, the number of turns per unit length in the longitudinal direction of the dielectric discharge tube must be maximized. When a high voltage is applied to the induction coil, the induction coil forms a capacitively coupled plasma, which reduces the stability of the discharge. Although the capacitively coupled plasma is advantageous for the initial discharge, it induces damage to the dielectric tube or the dielectric window that transmits the induction electric field due to ion acceleration caused by the capacitive coupling.

[0044] According to one embodiment of the present invention, in order to solve the problem of dielectric discharge tube damage caused by high voltage applied to the antenna, a capacitor is inserted between unit antennas arranged in each layer. Accordingly, even if more power is applied to the antenna, the dielectric discharge tube is not damaged. By using a capacitor between the unit antennas, the voltage applied to the antenna is reduced. Also, parasitic discharge caused by high voltage between the antenna and the power input and power output terminals is suppressed.

[0045] When a high voltage is applied to the antenna, ions are accelerated and collide with the surface, causing high temperature heating and damage. This problem makes it difficult to apply high power conditions to inductively coupled plasma, so measures to be taken include reducing the inductance or moving the antenna away from the tube.

[0046] According to one embodiment of the present invention, when a capacitor that appropriately offsets the voltage is placed in series between the unit antennas that make up the antenna, the maximum potential decreases inversely proportional to the number of times the antenna is divided, and damage to the dielectric tube is reduced even at high power.

[0047] According to a comparative example of the present invention, an experiment was carried out on an antenna having the same inductance without a capacitor and on a case where a capacitor is provided in series between unit antennas constituting the antenna. In the conventional antenna, the dielectric discharge tube was damaged even when 2 kW was applied. However, in the case of the present invention, the dielectric discharge tube was not damaged even after applying 8 kW of power. Not only was it not damaged, but the discharge was also improved. Specifically, N2 gas, which could not be injected at a power of 4 kW or less in the conventional antenna, could be injected from a power of 1.5 kW after the improvement.

[0048] Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein, and may be embodied in other forms. Rather, the embodiments described herein are provided so that the disclosure will be thorough and complete, and will fully convey the concept of the present invention to those skilled in the art. In the drawings, the dimensions of components are exaggerated for clarity. Parts designated with the same reference numerals throughout the specification refer to the same components.

[0049] FIG. 1 is a conceptual diagram illustrating a semiconductor substrate processing apparatus according to an embodiment of the present invention.

[0050] As shown in FIG. 1, the semiconductor substrate processing apparatus 2 includes a process chamber 92 for processing a substrate, and an inductively coupled plasma generator 100 for providing active species formed by inductively coupled plasma to the process chamber.

[0051] The process chamber 92 deposits a thin film (e.g., a tungsten thin film) on the substrate 94. The process chamber 92 receives a first process gas such as WF6, and receives activated species (e.g., hydrogen activated species) from the inductively coupled plasma generator 100. The activated species are generated by hydrogen (H2) plasma. The process chamber 92 includes a gas distributor 91. The gas distributor 91 receives a first process gas from a process gas supply unit 96, and receives activated species from the inductively coupled plasma generator 91. The gas distributor 91 spatially distributes the supplied gas to deposit a uniform thin film on the substrate.

[0052] The inductively coupled plasma generator 100 is a remote plasma source. The inductively coupled plasma generator 100 generates highly efficient hydrogen plasma at a high pressure of several Torr. The inductively coupled plasma generator 100 includes an inductive discharge module 191 and an RF power supply 140 for supplying power to the inductive discharge module 101. The inductively coupled plasma generator 100 receives a second process gas, generates activated species using inductively coupled plasma, and supplies the activated species to the process chamber 92.

[0053] The process chamber 92 includes a substrate holder 93 arranged parallel to and facing the gas distributor 91, and a substrate 94 arranged on the substrate holder 93. The substrate holder 93 is heated for chemical vapor deposition. The substrate is a semiconductor substrate. More specifically, the substrate is a silicon semiconductor substrate. The process chamber 92 is evacuated by a vacuum pump 95.

[0054] According to a modified embodiment of the present invention, the activated species are provided directly to the process chamber without passing through the gas distribution unit 91 .

[0055] According to modified embodiments of the present invention, the substrate processing apparatus is not limited to performing a chemical vapor deposition process, but may perform various other processes.

[0056] According to a modified embodiment of the present invention, the inductively coupled plasma apparatus 100 is not limited to be used in a chemical vapor deposition process, but is also used in a cleaning process of the process chamber. For example, the substrate processing apparatus 2 includes a separate remote plasma source, which discharges NF3 and supplies it to the process chamber 92 to perform a cleaning process. In this case, since the process environment of the process chamber is changed by fluorine, the inductively coupled plasma apparatus 100 of the present invention supplies hydrogen activation species to the process chamber 92. As a result, fluorine adsorbed on the inner wall of the process chamber 92 reacts with the hydrogen activation species and is removed.

[0057] FIG. 2A is a conceptual diagram illustrating an inductively coupled plasma generating apparatus according to one embodiment of the present invention.

[0058] FIG. 2B is a circuit diagram illustrating the inductively coupled plasma generating device of FIG. 2A.

[0059] FIG. 2C is a diagram illustrating voltage distribution in the inductively coupled plasma generating apparatus of FIG. 2A.

[0060] FIG. 2D is a plan view illustrating the inductively coupled plasma generating apparatus of FIG. 2A.

[0061] FIG. 2E is a plan view illustrating the induction coil of the inductively coupled plasma generation device of FIG. 2A.

[0062] As shown in FIG. 2A to FIG. 2E, the inductively coupled plasma generating apparatus 100 includes a dielectric tube 130 extending in a length direction, a first inductive coil structure 110 arranged to enclose the dielectric tube and generate inductively coupled plasma within the dielectric tube, an RF power source 140 providing a positive output and a negative output of opposite phases to each other and supplying a positive output and a negative output of RF power to both ends of the first inductive coil structure, respectively, and changing a driving frequency, a first main capacitor 121 arranged between a positive output end of the RF power source and one end of the first inductive coil structure, and a second main capacitor 122 arranged between a negative output end of the RF power source and the other end of the first inductive coil structure.

[0063] The first induction coil structure 110 includes induction coils 112, 114, 116, and 118 that are connected in series to each other and arranged in different layers, each layer having at least one turn, and auxiliary capacitors 113, 115, and 117 that are arranged between adjacent induction coils to distribute voltage applied to the induction coils.

[0064] The driving frequency of the RF power source 140 is several hundreds of kHz to several MHz. The output power of the RF power source 140 is several hundreds of watts to several tens of kilowatts. The RF power source 140 supplies power to a time-varying load (inductively coupled plasma) through a first inductive coil structure. The inductive coil of the first inductive coil structure 110 is electromagnetically coupled to the inductively coupled plasma. Therefore, a device capable of matching impedance between the RF power source 140 and the first inductive coil structure 110 is required. The RF power source 140 has first and second outputs of opposite phases. At a specific time, the first and second outputs have opposite phases with respect to ground.

[0065] A typical impedance matching network performs impedance matching using two variable reactance elements (e.g., vacuum variable capacitors) or a transformer. In this case, it is difficult for the first induction coil structure 110 to satisfy a stable resonance condition with the driving frequency. Therefore, an RF power source having a variable driving frequency is used so that a pair of adjacent induction coils and auxiliary capacitors in the first induction coil structure satisfy a series resonance condition.

[0066] The dielectric tube 130 has a cylindrical shape and extends in the length direction. The dielectric tube 130 is made of a material that can withstand high temperatures, such as glass, quartz, ceramic, alumina, or sapphire. The dielectric tube 130 has an inner diameter of several tens of millimeters. The dielectric tube 130 has a length of several tens of centimeters. A cylindrical inductively coupled plasma device includes a cylindrical dielectric discharge tube and an antenna that encases the discharge tube. In a cylindrical inductively coupled plasma, the induction electric field does not perpendicularly enter the dielectric discharge tube, so there is less damage caused by ion bombardment. The cylindrical inductively coupled plasma generates an induction electric field in the central axis direction of a cylindrical dielectric discharge tube. However, if a high voltage is applied to the antenna, the antenna generates a capacitively coupled plasma and heats the dielectric tube. Therefore, a new induction coil structure is required to prevent a high voltage from being applied to the antenna.

[0067] The induction field in the first induction coil structure 110 depends on the driving frequency and the current (or the number of turns per unit length). Also, the maximum voltage applied to the first induction coil structure 110 depends on the total impedance and the current of the first induction coil structure 110. The impedance of the first induction coil structure 110 depends on the inductance and the driving frequency of the first induction coil structure. Therefore, if the inductance of the first induction coil structure is increased to reduce the maximum voltage applied to the first induction coil structure, the strength of the induction field increases, but the high maximum voltage increases the effect of the storage coupling. Therefore, in order to reduce the impedance of the first induction coil structure, the first induction coil structure 10 includes auxiliary capacitors 113, 115, and 117 inserted between the induction coils 112, 114, 116, and 118 and the adjacent induction coils. Also, the induction coils and the adjacent auxiliary capacitors form a series resonant circuit with each other. The induction coils and the auxiliary capacitors are electrically alternately arranged and connected in series with each other. Thus, the first induction coil structure provides an overall low impedance.The number of the auxiliary capacitors is one less than the number of the induction coils.

[0068] Also, the first induction coil structure 110 forms a complete resonant circuit as a whole. To this end, a first main capacitor 121 is connected to one end of the first induction coil structure 110, and a second main capacitor 122 is connected to the other end of the first induction coil structure 110. Meanwhile, in order to form a complete resonant circuit, the capacitance C2 of the first main capacitor 121 is twice the capacitance C1 of the auxiliary capacitor, 2C1.

[0069] When such a resonant circuit is configured, the maximum voltage applied to the first induction coil structure 110 is inversely proportional to the multiples divided by the respective induction coils.

[0070] The first induction coil structure 110 includes induction coils 112, 114, 116, and 118 that are connected in series to each other and arranged in different layers, each layer having at least one turn, and auxiliary capacitors 113 and 115 that are arranged between adjacent induction coils to distribute voltage applied to the induction coils.

[0071] The induction coils include first to fourth induction coils 112, 114, 116, and 118. The auxiliary capacitors include first to third auxiliary capacitors 113, 115, and 117. The first to fourth induction coils 112, 114, 116, and 118 each have the same inductance L1. Also, the first to third auxiliary capacitors 113, 115, and 117 each have the same capacitance C1. Each of the first to third auxiliary capacitors 113, 115, and 117 has 2C1 and is represented as a pair of virtual capacitors connected in series. Thus, the first main capacitor 121, the first induction coil 112, and the virtual capacitors form a resonant circuit to reduce the overall voltage.

[0072] Compared to the case where the auxiliary capacitors 113, 115, and 117 are not connected, the voltage decreases inversely proportional to the number of induction coils by connecting the auxiliary capacitors. Nevertheless, the overall number of turns per unit length of the dielectric tube is maintained. To satisfy this resonance condition, the driving frequency is controlled to match the resonance frequency.

[0073] Also, in order to further increase the number of turns per unit length of the dielectric tube and increase the strength of the induced electric field, each of the induction coils 112, 114, 116, and 118 is a 3-turn coil or a 4-turn coil. The induction coils 112, 114, 116, and 118 are stacked vertically and densely to each other, and require space for electrical connection. To satisfy this, each induction coil does not have a portion that jumps across the layout plane, and the input and output ends of each induction coil must not be placed in a portion where they are stacked together. For this purpose, the following induction coil is proposed.

[0074] The induction coils 112, 114, 116, and 118 include first to fourth induction coils 112, 114, 116, and 118 that are sequentially stacked. The auxiliary capacitors 113, 115, and 117 include first to third auxiliary capacitors 113, 115, and 117.

[0075] The auxiliary capacitors between the induction coils reverse the potentials in the opposite direction. That is, the turn (or the first arc) closest to the dielectric tube and the turn (the fourth arc) furthest away from the dielectric tube on the same layout plane are induced to have opposite potentials. Inside the dielectric tube, the potentials of the induction coils are offset, and no electrostatic electric field due to capacitive coupling appears toward the dielectric tube. This reduction in the electrostatic electric field reduces the capacitive coupling effect.

[0076] In a conventional antenna, a large potential difference occurs between both ends due to inductance, and this large potential difference accelerates ions, causing energy loss and heating and damaging the dielectric tube. However, the auxiliary capacitor placed between the induction coils reduces the potential difference and sets the potentials inside and outside each induction coil opposite to each other. As a result, the potentials of opposite signs act as a dipole field inside the dielectric tube and reduce the electrostatic electric field. Each of the induction coils 112, 114, 116, and 118 has multiple windings wound from the inside to the outside on the same plane.

[0077] The first induction coil 112 is disposed to enclose the dielectric tube. The second induction coil 114 is rotated 90 degrees counterclockwise in preparation for the first induction coil 112 being disposed, and is aligned with the lower part of the first induction coil 112. The third induction coil 116 is rotated 90 degrees counterclockwise in preparation for the second induction coil 114 being disposed, and is aligned with the lower part of the second induction coil 114. The fourth induction coil 118 is rotated 90 degrees counterclockwise in preparation for the third induction coil 116 being disposed, and is aligned with the lower part of the third induction coil 116. One end of the first induction coil 112 is connected to the positive output terminal of the RF power source 140 through the first main capacitor 121. The other end of the first induction coil 112 is connected to one end of the second induction coil 114 through the first auxiliary capacitor 113. The other end of the second induction coil 114 is connected to one end of the third induction coil 116 through the second auxiliary capacitor 115. The other end of the third induction coil 116 is connected to one end of the fourth induction coil 118 through the third auxiliary capacitor 117. The other end of the fourth induction coil 118 is connected to the negative output terminal of the RF power source 140 through the second main capacitor 122. The first to fourth induction coils are stacked in sequence, rotated by 90 degrees each, to maintain overall azimuth symmetry.

[0078] The voltage (e.g., 2V) of the innermost winding of each induction coil is in opposite phase to the voltage (e.g., -2V) of the outermost winding. Also, the voltages of the innermost windings of all induction coils are the same. This minimizes parasitic capacitance between adjacent induction coils and improves discharge characteristics. Also, since the plasma inside the dielectric tube sees the same voltage due to the inner windings, localized ion sputtering is reduced.

[0079] The maximum voltage can be reduced by dividing the induction coil and inserting an auxiliary capacitor between the divided induction coils. However, the number of turns per unit length must be increased to provide a sufficient induction field. To increase the number of turns per unit length, the number of turns of each induction coil 112, 114, 116, 118 is increased. However, each induction coil must be arranged on the same layout plane. If each induction coil has wiring that goes out of the layout plane, it will interfere with the dense stacking of induction coils arranged on adjacent layers. Each induction coil has 3 or 4 turns on the same layout plane.

[0080] According to a modified embodiment of the present invention, the number of turns of each induction coil is modified to be more than 5 turns.

[0081] Each of the induction coils 112, 114, 116, and 118 has a portion that is open in a first direction (x-axis direction) in a Cartesian coordinate system, has a first central angle, is disposed on a placement plane, and has a constant first radius, a second arc portion 22a has a second central angle that is less than the first central angle, is disposed on the placement plane, has a second radius that is greater than the first radius, and is disposed so as to have the same central axis as the central axis of the first arc portion 22a, a third arc portion 22c has a third central angle that is less than the second central angle, is disposed on the placement plane, has a third radius that is greater than the second radius, and is disposed so as to have the same central axis as the central axis of the first arc portion, and a fourth central angle that is less than the third central angle, is disposed on the placement plane, and has a fourth radius that is greater than the third radius. The fourth arc portion 22d is disposed to have the same central axis as the central axis of the first arc portion, a first connecting portion 23a is disposed on the arrangement plane, is connected to one end of the first arc portion 22a, and extends in the first direction (x-axis direction), a first arc connecting portion 24a is disposed on the arrangement plane and is U-shaped to connect the other end of the first arc portion 22a to one end of the second arc portion 22b, a second arc connecting portion 24b is U-shaped to connect the other end of the second arc portion to one end of the third arc portion, a third arc connecting portion 24c is U-shaped to connect the other end of the third arc portion to one end of the fourth arc portion, and a second connecting portion 23b is disposed on the arrangement plane and is connected to the other end of the fourth arc portion 22d, and extends in the first direction. The fourth central angle is 270 degrees or more. The first arc-shaped connector 24a, the second arc-shaped connector 24b, and the third arc-shaped connector 24c are arranged so as not to overlap with each other. The first arc-shaped connector 24a is arranged within a region defined by the second arc-shaped connector 24b.

[0082] In each of the induction coils 112, 114, 116, and 118, the spacing between the windings (e.g., the first through fourth arc portions) is constant. For example, the spacing is 1 mm to 3 mm. In order for the induction coil to provide sufficient azimuthal symmetry, the first through fourth central angles are 270 degrees or more. Meanwhile, the first through fourth arc portions maintain sufficient spacing of several millimeters or more to suppress arcing at atmospheric pressure due to voltage differences.

[0083] The induction coils arranged in the adjacent layers are electrically insulated by an insulating spacer 150. The insulating spacer 150 is inserted into the outer surface of the dielectric tube 130 in the form of a washer and is a thin disk having a through hole in the center. The insulating spacer 150 is made of glass, plastic, or Teflon. The thickness of the insulating spacer 150 is on the order of millimeters. The inner radius of the insulating spacer 150 is substantially the same as the outer radius of the dielectric tube 130, and the outer radius of the insulating spacer 150 is substantially the same as the radius of the outermost shell of the induction coil. The width between the inner radius and the outer radius of the insulating spacer 150 is several centimeters to tens of centimeters.

[0084] Meanwhile, at least a portion of the induction coils 112, 114, 116, and 118 is molded with ceramic paste. A ceramic mold 152 that encases at least a portion of the induction coils is in thermal contact with the dielectric tube 130. Thus, when a refrigerant flows through the induction coils 112, 114, 116, and 118, the cooled induction coils cool the ceramic mold 152, and the ceramic mold 152 indirectly cools the dielectric tube 130.

[0085] Each of the induction coils 112, 114, 116, 118 is in the form of four turns wound outward from the dielectric tube in each layer. A pair of induction coils in adjacent layers are connected in series with an auxiliary capacitor connected in series therebetween. Thus, the capacitance of the auxiliary capacitor cancels the inductance of the induction coil. The four induction coils form one group. The four induction coils are arranged at 90 degree intervals in a counterclockwise direction.

[0086] Both ends of the dielectric tube are sealed by flanges. An upper flange 132 fixes one end of the dielectric tube and includes a nozzle 131 that provides a mixture of hydrogen and nitrogen gas. Inductive coils 112, 114, 116, and 118 surround the center of the dielectric tube to generate inductively coupled plasma within the dielectric tube. A lower flange 134 fixes the other end of the dielectric tube, and the other end of the dielectric tube is provided with a gas that is further decomposed by the inductively coupled plasma.

[0087] FIG. 3A is a conceptual diagram illustrating an inductively coupled plasma generating apparatus according to another embodiment of the present invention.

[0088] FIG. 3B is a circuit diagram illustrating the inductively coupled plasma generating device of FIG. 3A.

[0089] FIG. 3C is a diagram illustrating voltage distribution in the inductive coil structure of the inductively coupled plasma generating apparatus of FIG. 3A.

[0090] As shown in FIGS. 3A to 3C, the inductively coupled plasma generator 200 includes a dielectric tube 130 extending in a length direction, a first inductive coil structure 110 disposed to enclose the dielectric tube and generate inductively coupled plasma within the dielectric tube, an RF power source 140 that provides positive and negative outputs of opposite phases to each other, supplies positive and negative outputs of RF power to both ends of the first inductive coil structure, and changes a driving frequency, a first main capacitor 121 disposed between the positive output terminal of the RF power source and one end of the first inductive coil structure, and a second main capacitor 122 disposed between the negative output terminal of the RF power source and the other end of the first inductive coil structure.

[0091] The second induction coil structure 210 is disposed to wrap the dielectric tube 130 and is spaced apart from the first induction coil structure 110 in the longitudinal direction. The second induction coil structure 210 has the same structure as the first induction coil structure 110 and generates inductively coupled plasma within the dielectric tube 130.

[0092] One end of the second induction coil structure 210 is connected to one end of the first induction coil structure 110, and the other end of the second induction coil structure 210 is connected to the other end of the first induction coil structure 110. The first induction coil structure 110 and the second induction coil structure 210 are connected in parallel to each other between the first main capacitor 121 and the second main capacitor 122.

[0093] The induction coils 112, 114, 116, and 118 constituting the first induction coil structure 110 and the second induction coil structure 210 each have the same first inductance L1. The auxiliary capacitors 113, 115, and 117 constituting the first induction coil structure 110 and the second induction coil structure 210 each have the same first capacitance C1. The driving frequency of the RF power source 140 is controlled to match a resonant frequency of the first inductance L1 and the first capacitance C1 connected in series.

[0094] The first main capacitor and the second main capacitor each have the same second capacitance C2, and the second capacitance C2 is four times the first capacitance C1.

[0095] One end of the first induction coil structure 110 and one end of the second induction coil structure 210 are disposed adjacent to each other. One end of the first induction coil structure and one end of the second induction coil structure are connected to each other and connected to the first main capacitor 121. The other end of the first induction coil structure 110 and the other end of the second induction coil structure 210 are connected to each other and connected to the second main capacitor.

[0096] The first induction coil structure 110 and the second induction coil structure 210 are arranged in mirror symmetry above / below with respect to one point of the dielectric discharge tube 130. Current is distributed above / below from the center and then collected at both ends.

[0097] Also, the first induction coil structure 110 and the second induction coil structure 210 form a complete resonant circuit as a whole. To achieve this, a first main capacitor 121 is connected to one end of the first induction coil structure 110 and one end of the first induction coil structure 210. A second main capacitor 122 is connected to the other end of the first induction coil structure 110 and the other end of the second induction coil structure. Meanwhile, in order to form a complete resonant circuit, the capacitance C2 of the first main capacitor 121 is 4C1, which is four times the capacitance C1 of the auxiliary capacitor. The first main capacitors are represented as capacitors connected in parallel to each other, having a capacitance of 2C1.

[0098] The induction coils include first to fourth induction coils 112, 114, 116, and 118. The auxiliary capacitors include first to third auxiliary capacitors 113, 115, and 117. The first to fourth induction coils 112, 114, 116, and 118 each have the same inductance L1. Also, the first to third auxiliary capacitors 113, 115, and 117 each have the same capacitance C1. Each of the first to third auxiliary capacitors 113, 115, and 117 has 2C1 and is represented as a pair of virtual capacitors connected in series. As a result, a part 2C1 of the first main capacitor 121, the first induction coil 112, and the virtual capacitor 2C1 form a resonant circuit to reduce the overall voltage.

[0099] The first induction coil structure 110 and the second induction coil structure 210 are connected in parallel to each other and include a total of eight induction coils. The induction coils of the first induction coil structure are arranged at 90 degree intervals in a counterclockwise direction. The induction coils of the second induction coil structure are arranged at 90 degree intervals in a clockwise direction.

[0100] An auxiliary capacitor is disposed between the induction coils to cancel the imaginary part of the impedance. The first induction coil structure and the second induction coil structure of two groups of four connected in series are connected in parallel at both ends and then electrically connected to an external terminal.

[0101] The auxiliary capacitors between the induction coils reverse the potentials in the opposite directions. That is, the innermost turn (or the first arc portion) and the outermost turn (the fourth arc portion) of the dielectric tube on the same layout plane are induced to have opposite potentials. Inside the dielectric tube, the potentials of the induction coils are offset, and no electrostatic field due to capacitive coupling appears toward the dielectric tube. This reduction in the electrostatic field reduces the capacitive coupling effect.

[0102] In a conventional antenna, a large potential difference occurs between both ends due to inductance, which accelerates ions, causing energy loss and heating up the dielectric tube, resulting in damage. However, the auxiliary capacitor placed between the induction coils reduces the potential difference and sets the potentials inside and outside each induction coil to be opposite to each other. As a result, the potentials of opposite signs act as a dipole field inside the dielectric tube, reducing the electrostatic field.

[0103] FIG. 4A is a conceptual diagram illustrating an inductively coupled plasma generating apparatus according to still another embodiment of the present invention.

[0104] FIG. 4B is a circuit diagram illustrating the inductively coupled plasma generating device of FIG. 4A.

[0105] FIG. 4C is a diagram illustrating voltage distribution in the inductive coil structure of the inductively coupled plasma generating apparatus of FIG. 4A.

[0106] FIG. 4D is a plan view illustrating the induction coil of the inductively coupled plasma generation device of FIG. 4A.

[0107] As shown in FIGS. 4A to 4D , the inductively coupled plasma generator 300 includes a dielectric tube 130 extending in a length direction, a first inductive coil structure 310 disposed to enclose the dielectric tube and generate inductively coupled plasma within the dielectric tube, an RF power source 140 that provides positive and negative outputs of opposite phases to each other, supplies positive and negative outputs of RF power to both ends of the first inductive coil structure, and changes a driving frequency, a first main capacitor 121 disposed between the positive output terminal of the RF power source and one end of the first inductive coil structure, and a second main capacitor 122 disposed between the negative output terminal of the RF power source and the other end of the first inductive coil structure.

[0108] The first main capacitor 121 and the second main capacitor 122 each have the same second capacitance C2, and the second capacitance C2 is twice the first capacitance C1 of the auxiliary capacitor.

[0109] The induction coils include first to fourth induction coils 312, 314, 316, and 318. The auxiliary capacitors include first to third auxiliary capacitors 113, 115, and 117. The first to fourth induction coils 312, 314, 316, and 318 each have the same inductance L1. Also, the first to third auxiliary capacitors 113, 115, and 117 each have the same capacitance C1. Each of the first to third auxiliary capacitors 113, 115, and 117 has 2C1 and is represented as a pair of virtual capacitors connected in series. As a result, a part 2C1 of the first main capacitor 121, the first induction coil 312, and the virtual capacitor 2C1 form a resonant circuit to reduce the overall voltage.

[0110] Each of the induction coils 312, 314, 316, and 318 has a portion that is open in a first direction in a Cartesian coordinate system, has a first central angle, is disposed on a placement plane, and has a certain first radius. A second arcuate portion 32a has a second central angle that is less than the first central angle, is disposed on the placement plane, has a second radius that is greater than the first radius, and is disposed to have the same central axis as the central axis of the first arcuate portion. A third arcuate portion 32b has a third central angle that is less than the second central angle, is disposed on the placement plane, has a third radius that is greater than the second radius, and is disposed to have the same central axis as the central axis of the first arcuate portion. a third arc portion 32c arranged to have one central axis, a first connecting portion 33a arranged on the arrangement plane, connected to one end of the first arc portion, and extending in the first direction, a first arc connecting portion 34a arranged on the arrangement plane and connected to the other end of the first arc portion and one end of the second arc portion, a second arc connecting portion 34b arranged on the arrangement plane and connected to the other end of the second arc portion and one end of the third arc portion, and a second connecting portion 33b arranged on the arrangement plane and connected to the other end of the third arc portion and extending in the first direction. The third central angle is 270 degrees or more.

[0111] FIG. 5A is a conceptual diagram illustrating an inductively coupled plasma generating apparatus according to still another embodiment of the present invention.

[0112] FIG. 5B is a plan view illustrating the induction coil of the inductively coupled plasma generation device of FIG. 5A.

[0113] 5A and 5B, the inductively coupled plasma generator 400 includes a dielectric tube 130 extending in a length direction, a first inductive coil structure 410 arranged to enclose the dielectric tube and generate inductively coupled plasma within the dielectric tube, an RF power source 140 providing positive and negative outputs of opposite phases to each other, supplying positive and negative outputs of RF power to both ends of the first inductive coil structure, respectively, and changing a driving frequency, a first main capacitor 121 arranged between the positive output terminal of the RF power source and one end of the first inductive coil structure, and a second main capacitor 122 arranged between the negative output terminal of the RF power source and the other end of the first inductive coil structure.

[0114] The first main capacitor 121 and the second main capacitor 122 each have the same second capacitance C2, and the second capacitance C2 is twice the first capacitance C1 of the auxiliary capacitor. The induction coils include first to fourth induction coils 412, 414, 416, and 418. The auxiliary capacitors include first to third auxiliary capacitors 113, 115, and 117. The first to fourth induction coils 412, 414, 416, and 418 each have the same inductance L1. Also, the first to third auxiliary capacitors 113, 115, and 117 each have the same capacitance C1. Each of the first to third auxiliary capacitors 113, 115, and 117 has 2C1 and is represented as a pair of virtual capacitors connected in series. As a result, a part 2C1 of the first main capacitor 121, the first induction coil 412, and the virtual capacitor 2C1 form a resonant circuit to reduce the overall voltage.

[0115] Each of the induction coils 412, 414, 416, and 418 has a portion that is open in a first direction in a Cartesian coordinate system, has a first central angle, is disposed on an arrangement plane, and includes a first arc portion 42a having a certain first radius, a second arc portion 42b having a second central angle less than the first central angle, is disposed on the arrangement plane, has a second radius greater than the first radius, and is disposed to have the same central axis as the central axis of the first arc portion, a first connecting portion 43a disposed on the arrangement plane, connected to one end of the first arc portion, and extended in the first direction, a first arc connecting portion 44a disposed on the arrangement plane and having a "U" shape connecting the other end of the first arc portion to one end of the second arc portion, and a second connecting portion 43b disposed on the arrangement plane, connected to the other end of the second arc portion, and extended in the first direction. The second central angle is 270 degrees or more.

[0116] As described above, the present invention has been illustrated and described with respect to specific preferred embodiments, but the present invention is not limited to such embodiments and includes all various forms of embodiments that can be made by a person having ordinary skill in the art to which the invention pertains without departing from the technical spirit of the present invention as claimed in the claims. [Explanation of symbols]

[0117] 110 First induction coil structure 112, 114, 116, 118 Induction coil 113, 115, 117 Auxiliary storage battery 121 First main capacitor 122 Second main capacitor

Claims

1. 1. An induction coil structure for generating an inductively coupled plasma in a dielectric tube, the induction coil structure comprising: a first induction coil including at least a first arc portion, a second arc portion, and a first connecting portion connecting one end of the first arc portion and one end of the second arc portion, the first arc portion having a first radius and being disposed closer to the dielectric tube than the second arc portion, the second arc portion having a second radius larger than the first radius and being disposed farther from the dielectric tube than the first arc portion, the first arc portion and the second arc portion being disposed in a first plane; a second induction coil offset from the first induction coil and including a third arc having at least a third radius, the third arc being disposed in a second plane; and a capacitor configured to be connected to the first induction coil and the second induction coil, the capacitor configured to be connected to the other end of the first arc portion via a first connecting line, the capacitor configured to be connected to one end of the third arc portion via a second connecting line, and the first connecting line overlapping the first connecting portion when viewed from a direction perpendicular to the first plane; Equipped with The first induction coil, the second induction coil, and the capacitor are electrically connected in series.

2. The induction coil structure of claim 1 , wherein the third radius is greater than the first radius.

3. 2. The induction coil structure of claim 1, wherein the first connecting portion is "U" shaped.

4. 2. The inductive coil structure of claim 1, wherein when an RF voltage is applied to the inductive coil structure, the current directions in the first arc portion, the second arc portion, and the third arc portion are all the same.

5. The induction coil structure of claim 4 , wherein all the current directions are either clockwise or counterclockwise.

6. the second induction coil further comprises a fourth arcuate portion having a fourth radius smaller than the third radius; the fourth arc portion is disposed within the second plane and closer to the dielectric tube than the third arc portion; 2. The induction coil structure of claim 1.

7. The induction coil structure of claim 6 , wherein the second induction coil further comprises a second connection portion connecting the other end of the third arc portion and one end of the fourth arc portion.

8. 7. The induction coil structure of claim 6, wherein a first direction from the central axis of the dielectric tube to the first coupling portion is different from a second direction from the central axis of the dielectric tube to the second coupling portion.

9. 9. The induction coil structure of claim 8, wherein the angle between the first direction and the second direction is 90 degrees.

10. The induction coil structure further includes at least one separate induction coil other than the first induction coil and the second induction coil, Each of the at least one separate induction coil includes at least an inner arc portion, an outer arc portion, and a connecting portion connecting one end of the inner arc portion and one end of the outer arc portion, One of the at least one separate induction coil is connected to the second induction coil via the capacitor.

2. The induction coil structure of claim 1.

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