KR20210081307A - The Plasma Generation Apparatus And The Operational Method Of The Same - Google Patents

Abstract

A plasma generating device according to one embodiment of the present invention comprises: a pair of electrodes disposed in a dielectric discharge tube; an initial discharge induction coil module; and a main discharge induction coil module. The initial discharge induction coil module and the main discharge induction coil module are connected to an RF power supply, and the RF power supply provides RF electric power of different resonant frequencies to the initial discharge induction coil module and the main discharge induction coil module, respectively. Therefore, an objective of the present invention is to provide the plasma generating device that generates a stable induction coupled plasma.

Description

Plasma Generation Apparatus And The Operational Method Of The Same

The present invention relates to a plasma generating device, and more particularly, to an inductively coupled plasma device for performing discharge at atmospheric pressure or above atmospheric pressure.

Inductively coupled plasmas are typically formed using a driving frequency of several MHz at a pressure of several hundred milliTorr (mTorr). However, in such an inductively coupled plasma, it is difficult to discharge at atmospheric pressure or at a pressure of several hundred torr or more because the intensity of the induced electric field is small. Therefore, sufficient strength of the induced electric field is required and a separate means for initial discharge is required. Even if the atmospheric pressure discharge is maintained, the discharge cannot be performed for a long time due to thermal damage caused by ions from the plasma of the dielectric tube.

When RF power is applied to an induction coil surrounding a dielectric tube to perform inductively coupled plasma discharge, the inductively coupled plasma heats the dielectric tube, and the dielectric tube is heated and damaged. Therefore, the high-power inductively coupled plasma has a structural limitation.

The inventor of the present invention proposes a swirl flow to maintain plasma stability in Korean Patent Registration KR 10-1657303 B1. However, an antenna having a plurality of windings has a limitation in atmospheric pressure discharge because the antenna voltage accelerates ions to the tube wall and causes thermal damage at the same time as the induced electric field increases during discharge.

The inventor of the present invention proposes an inductively coupled plasma generating device having a voltage distribution structure by inserting a capacitor between antennas in Korean Patent Registration KR 0-1826883 B1. However, Korean Patent Registration KR 10-1826883 B1 induces an initial discharge in a state where the driving frequency is out of the resonance condition, but it is difficult to stably ignite the atmospheric pressure discharge due to the small strength of the electric field.

One technical problem to be solved by the present invention is to provide a plasma generating apparatus for generating stable inductively coupled plasma at atmospheric pressure level or a pressure of several hundred torr or more.

Atmospheric pressure plasma generating apparatus according to an embodiment of the present invention, a dielectric discharge tube; An initial discharge induction coil module comprising an initial discharge induction coil surrounding the dielectric cylindrical tube and having a plurality of windings to generate an atmospheric pressure initial discharge, and an initial discharge capacitor connected in series with the initial discharge induction coil to provide a first resonant frequency ; first and second electrodes respectively disposed above and below the initial discharge induction coil to provide an initial discharge seed; a DC power supply for applying a DC high voltage between the first electrode and the second electrode; a main discharge induction coil module having a second resonant frequency and receiving the initial discharge generated by the initial discharge induction coil module to generate a main inductively coupled plasma; and an RF power supply that provides RF power to the initial discharge induction coil module and the main discharge induction coil module connected in parallel and changes a driving frequency. The main discharge induction coil module may include: a plurality of unit antennas spaced apart from the initial discharge induction coil, respectively disposed on a plurality of arrangement planes perpendicular to a central axis of the dielectric discharge tube, and connected in series with each other; a first main capacitor and a second main capacitor respectively disposed at both ends of the unit antennas; and auxiliary capacitors respectively connected in series between the unit antennas. The RF power source induces an initial discharge in the initial discharge induction coil at the first resonant frequency with the aid of the DC high voltage. The RF power source performs main discharge by changing the driving frequency from the first resonant frequency to the second resonant frequency.

In one embodiment of the present invention, it further comprises a first detection sensor for detecting the current or voltage flowing through the initial discharge induction coil. The RF power may detect a transition from the capacitive coupling mode to the inductive coupling mode using the output of the first detection sensor and change the driving frequency from the first resonant frequency to the second resonant frequency.

In an embodiment of the present invention, the first electrode may be disposed on the initial discharge induction coil and be charged with a positive DC high voltage. The second electrode is disposed under the initial discharge induction coil, has a “C” shape to surround the dielectric discharge tube, and may be charged with a negative DC high voltage.

In one embodiment of the present invention, the DC power source, AC-DC converter for converting commercial power into DC voltage; a high voltage pulse generator that receives the DC voltage and generates a positive DC high voltage pulse and a negative DC high voltage pulse; and a controller for controlling the high voltage pulse generator.

In an embodiment of the present invention, the high voltage pulse generator comprises: a first transformer including a primary coil receiving the DC voltage of the AC-DC converter and a secondary coil generating a positive DC high voltage pulse; a first power transistor connected to the primary coil of the first transformer; a second transformer including a primary coil receiving the DC voltage of the AC-DC converter and a secondary coil generating a negative DC high voltage pulse; and a second power transistor connected to the primary coil of the second transformer. The controller may control gates of the first power transistor and the second power transistor. One end of the secondary coil of the first transformer may output a positive DC high voltage pulse, and the other end of the secondary coil of the first transformer may be grounded. One end of the secondary coil of the second transformer may output a negative DC high voltage pulse, and the other end of the secondary coil of the second transformer may be grounded.

In an embodiment of the present invention, the initial discharge induction coil has a solenoid shape and may be wound in multiple layers.

In one embodiment of the present invention, the initial discharge induction coil may have a three-layer structure of an internal solenoid coil, an intermediate solenoid coil, and an external solenoid coil.

In an embodiment of the present invention, the initial discharge capacitor may be disposed at both ends of the initial discharge induction coil, respectively.

In one embodiment of the present invention, the cross section of the coil constituting the unit antenna may be rectangular.

In an embodiment of the present invention, the unit antenna includes: a first antenna disposed in contact with the dielectric discharge tube in a plane of arrangement perpendicular to a central axis of the dielectric discharge tube and forming a loop; a second antenna disposed to surround the first antenna and forming a loop; and a third antenna disposed to surround the second antenna and forming a loop.

In an embodiment of the present invention, the unit antennas may be arranged on different arrangement planes and there may be ten.

In an embodiment of the present invention, the unit antennas may be divided into a first group including 5 unit antennas and a second group including 5 different unit antennas. The unit antennas constituting the first group may be disposed at intervals of 72 degrees along the azimuth direction, and the unit antennas constituting the second group may be disposed at intervals of 72 degrees along the azimuth direction.

In an embodiment of the present invention, the unit antenna may include a plurality of windings disposed on the same arrangement plane, and may further include an insulating spacer in the shape of a “ㅛ” to insulate the plurality of windings.

In an embodiment of the present invention, the first resonant frequency and the second resonant frequency may be spaced apart from each other by 0.2 MHz or more.

In an embodiment of the present invention, the first resonant frequency may be greater than the second resonant frequency.

In one embodiment of the present invention, the capacitance of the first main capacitor may be equal to the capacitance of the second main capacitor, and the capacitance of the first main capacitor may be twice the capacitance of the auxiliary capacitor. .

In an embodiment of the present invention, a first voltage drop induced in the initial discharge induction coil at the first resonant frequency may be greater than a second voltage drop induced in the unit antenna at the second resonant frequency.

In an embodiment of the present invention, the sum of the inductances of the plurality of unit antennas may be greater than the inductance of the initial discharge induction coil.

A method of operating an atmospheric pressure plasma generating apparatus according to an embodiment of the present invention comprises: providing an initial discharge seed by applying a DC high voltage to a first electrode and a second electrode spaced apart from each other in a dielectric discharge tube; An initial discharge induction coil module comprising an initial discharge induction coil surrounding the dielectric cylindrical tube and having a plurality of windings to generate an atmospheric pressure initial discharge, and an initial discharge capacitor connected in series with the initial discharge induction coil to provide a first resonant frequency performing an initial discharge by providing AC power of the first resonant frequency; Inducing a main inductively coupled plasma from the initial discharge by providing AC power having a second resonant frequency different from the first resonant frequency to a main discharge induction coil module connected in parallel with the initial discharge induction coil module.

In one embodiment of the present invention, the method further includes: sensing a current flowing through the initial discharge induction coil or a voltage drop applied to both ends of the initial discharge induction coil. When the current flowing through the initial discharge induction coil or the voltage drop applied to both ends of the initial discharge induction coil is equal to or greater than a threshold, the RF power source changes the driving frequency from the first resonant frequency to the second resonant frequency. A main discharge may be performed in the unit antennas.

In an embodiment of the present invention, the main discharge induction coil module is disposed to be spaced apart from the initial discharge induction coil, and the dielectric discharge tube is disposed on a plurality of arrangement planes perpendicular to a central axis, respectively, and connected in series with each other. a plurality of unit antennas; a first main capacitor and a second main capacitor respectively disposed at both ends of the unit antennas; and auxiliary capacitors respectively connected in series between the unit antennas. The RF power source may induce an initial discharge in the initial discharge induction coil at the first resonant frequency with the aid of the DC high voltage. The RF power may change the driving frequency from the first resonant frequency to the second resonant frequency to perform main discharge in the unit antennas.

A plasma generating apparatus according to an embodiment of the present invention includes: a dielectric discharge tube; a seed charge generator generating seed charges in the dielectric discharge tube; An initial discharge induction coil module comprising an initial discharge induction coil surrounding the dielectric cylindrical tube and receiving the seed charge to generate an initial discharge, and a first impedance matching network connected to the initial discharge induction coil to provide a first resonant frequency ; a plurality of unit antennas disposed spaced apart from the initial discharge induction coil, surrounding the dielectric cylindrical tube, receiving the initial discharge to generate a main inductively coupled plasma, and a second resonant frequency connected to the unit antennas 2 main discharge induction coil module comprising an impedance matching network; and an RF power supply for supplying power to the initial discharge induction coil module and the main discharge induction coil module.

In an embodiment of the present invention, the seed charge generator may include: first and second electrodes disposed on the dielectric discharge tube to provide seed charge; and a DC power supply for applying a DC high voltage between the first electrode and the second electrode.

In one embodiment of the present invention, the seed charge generating unit, The first electrode may be disposed in contact with an outer wall of the dielectric discharge tube, and the second electrode may be disposed on a central axis of the dielectric discharge tube and electrically grounded.

In one embodiment of the present invention, the second electrode may be a nozzle for spraying a gas.

In one embodiment of the present invention, the DC power source, AC-DC converter for converting commercial AC power into DC voltage; a high voltage pulse generator receiving the DC voltage and generating at least one high voltage pulse from among a positive DC high voltage pulse and a negative DC high voltage pulse; and a controller for controlling the high voltage pulse generator.

In an embodiment of the present invention, the high voltage pulse generator may include: a first high voltage pulse generator configured to receive the DC voltage and generate a first high voltage pulse; and a first high voltage pulse generator configured to receive the DC voltage and generate a second high voltage pulse.

The controller for controlling the high voltage pulse generator includes: a first controller for controlling the first high voltage pulse generator; and a second controller controlling the second high voltage pulse generator. The first high voltage pulse is applied to the first electrode, the second high voltage pulse is applied to the second electrode, and the first electrode and the second electrode are spaced apart from each other on the outer wall of the dielectric discharge tube. can

In an embodiment of the present invention, the high voltage pulse generator comprises: a first transformer including a primary coil receiving the DC voltage of the AC-DC converter and a secondary coil generating a positive DC high voltage pulse; a first power transistor connected between ground and a primary coil of the first transformer; a second transformer including a primary coil receiving the DC voltage of the AC-DC converter and a secondary coil generating a negative DC high voltage pulse; and a second power transistor connected to the ground and the primary coil of the second transformer. The controller may control gates of the first power transistor and the second power transistor. One end of the secondary coil of the first transformer may output a positive DC high voltage pulse, and the other end of the secondary coil of the first transformer may be grounded. One end of the secondary coil of the second transformer may output a negative DC high voltage pulse, and the other end of the secondary coil of the second transformer may be grounded.

In one embodiment of the present invention, the high voltage pulse generator comprises: a transformer including a primary coil receiving the DC voltage of the AC-DC converter and a secondary coil generating a positive DC high voltage pulse; an inductor connected in parallel to the primary coil of the transformer; a power transistor having a grounded end and connected in series between the primary coil of the transformer; a resistor connected in parallel with the power transistor; a capacitor connected in parallel with the power transistor; and a diode disposed between the other end of the power transistor and the parallel-connected resistor and capacitor. The controller may control a gate of the power transistor, one end of the secondary coil of the transformer may output a negative DC high voltage pulse, and the other end of the secondary coil of the transformer may be grounded.

In an embodiment of the present invention, the high voltage pulse generator comprises: a transformer including a primary coil receiving the DC voltage of the AC-DC converter and a secondary coil generating a negative DC high voltage pulse; an inductor connected in parallel to the primary coil of the transformer; and a power transistor connected in series between the ground and the primary coil of the transformer. The controller may control a gate of the power transistor, one end of the secondary coil of the transformer may output a negative DC high voltage pulse, and the other end of the secondary coil of the transformer may be grounded.

In an embodiment of the present invention, the high voltage pulse generator comprises: a transformer including a primary coil receiving the DC voltage of the AC-DC converter and a secondary coil generating a negative DC high voltage pulse; an inductor connected in parallel to the primary coil of the transformer; a power transistor connected in series between ground and the primary coil of the transformer; One end is connected to the DC voltage of the AC-DC converter, the resistor and the capacitor connected in parallel with each other; and a diode having one end connected between the power transistor and the primary coil, and the other end connected to the other end of the parallel-connected resistor and the capacitor; may include. The controller may control a gate of the power transistor, one end of the secondary coil of the transformer may output a negative DC high voltage pulse, and the other end of the secondary coil of the transformer may be grounded.

In one embodiment of the present invention, the high voltage pulse generator comprises: a transformer including a primary coil receiving the DC voltage of the AC-DC converter and a secondary coil generating a positive DC high voltage pulse; an inductor connected in parallel to the primary coil of the transformer; a power transistor connected in series between ground and the primary coil of the transformer; a resistor connected in parallel with the power transistor; a capacitor connected in parallel with the power transistor; and a diode disposed between the other end of the power transistor and the parallel-connected resistor and capacitor. The primary coil and the secondary coil have a phase difference of 180 degrees, the controller controls the gate of the power transistor, and one end of the secondary coil of the transformer outputs a positive DC high voltage pulse, and the transformer The other end of the secondary coil of the perm may be grounded.

In an embodiment of the present invention, the first impedance matching network may include an initial discharge capacitor connected in series to the initial discharge induction coil.

In an embodiment of the present invention, the first impedance matching network may include a pair of initial discharge capacitors respectively connected to both ends of the initial discharge induction coil.

In an embodiment of the present invention, the first impedance matching network includes a transformer and a pair of initial discharge capacitors respectively connected to both ends of the initial discharge induction coil, and the primary coil of the transformer is an output terminal of the RF power source. , and the secondary coil of the transformer may be connected to both ends of an initial discharge induction coil connected in series with each other and a pair of initial discharge capacitors.

In an embodiment of the present invention, the first impedance matching network may include: a first initial discharge capacitor connected in parallel to the initial discharge induction coil; It may include a first initial discharge capacitor connected to each other in parallel, and a second initial discharge capacitor and a third initial discharge capacitor connected to both ends of the initial discharge induction coil, respectively.

In one embodiment of the present invention, in the main discharge induction coil module, the plurality of unit antennas are respectively disposed on a plurality of arrangement planes perpendicular to the central axis of the dielectric discharge tube and are connected in series with each other, and the auxiliary capacitors are Connected in series between adjacent unit antennas, the second impedance matching network may include a first main capacitor and a second main capacitor respectively connected to both ends of the series-connected unit antennas.

In one embodiment of the present invention, the RF power source, a rectifier for converting commercial AC power into DC power; an inverter that receives the DC power and converts it into RF power in response to switching signals of a controller; and a controller configured to control a driving frequency and power by controlling the switching signals. The RF power source may operate at the first resonant frequency during initial discharge and may operate at the second resonant frequency when a main inductively coupled plasma is generated.

In one embodiment of the present invention, the RF power supply, the first RF power supply providing AC power to the initial discharge induction coil module and operating at the first resonant frequency; and a second RF power supply that provides AC power to the main discharge induction coil module and operates at the second resonant frequency. The first RF power source includes: a first rectifier for converting AC power into DC power; a first inverter receiving the DC power of the first rectifier and providing AC power of a first resonance frequency to the initial discharge induction coil module; and a first controller configured to control an output of the first inverter. The second RF power source includes: a second rectifier for converting AC power into DC power; a second inverter receiving the DC power of the second rectifier and providing AC power of a second resonance frequency to the main discharge induction coil module; and a second control unit for controlling an output of the second inverter.

In an embodiment of the present invention, the RF power source includes: a rectifier for converting AC power into DC power; a first RF power supply receiving the DC power of the rectifier to provide AC power to the initial discharge induction coil module and operating at the first resonance frequency; and a second RF power source that receives the DC power from the rectifier to provide AC power to the main discharge induction coil module and operates at the second resonant frequency.

In an embodiment of the present invention, the first RF power source includes: a first inverter that receives the DC power of the rectifier and converts it into a first AC power of a first resonance frequency; and a first control unit for controlling the first inverter; The second RF power source is a second inverter that receives the DC power of the rectifier and converts it into AC power having a second resonance frequency; and a second controller configured to control the second inverter.

In an embodiment of the present invention, the first RF power source may operate in a frequency range of 4 MHz to 5 MHz, and the second RF power supply may operate in a frequency range of 400 kHz to 4 MHz.

In one embodiment of the present invention, each of the first inverter and the second inverter may have a full-bridge structure or a half-bridge structure.

In one embodiment of the present invention, the first detection sensor for sensing the current flowing in the initial discharge induction coil may be further included. The RF power may change the driving frequency from the first resonant frequency to the second resonant frequency by detecting a transition from the capacitive coupling mode to the inductive coupling mode using the output of the first detection sensor.

In one embodiment of the present invention, a second detection sensor for detecting a current flowing through the main discharge induction coil module may be further included. The RF power may detect that the main inductively coupled plasma is formed by using the output of the second detection sensor to cut off the power provided to the initial discharge induction coil module.

In an embodiment of the present invention, the first electrode may be disposed on the initial discharge induction coil and be charged with a positive DC high voltage. The second electrode is disposed under the initial discharge induction coil, has a “C” shape to surround the dielectric discharge tube, and may be charged with a negative DC high voltage.

In an embodiment of the present invention, the initial discharge induction coil has a solenoid shape and may be wound in multiple layers.

In one embodiment of the present invention, the initial discharge induction coil may have a three-layer structure of an internal solenoid coil, an intermediate solenoid coil, and an external solenoid coil.

In an embodiment of the present invention, the unit antenna may include: a first antenna disposed in contact with the dielectric discharge tube in a plane of arrangement perpendicular to a central axis of the dielectric discharge tube and forming a loop; a second antenna disposed to surround the first antenna and forming a loop; and a third antenna disposed to surround the second antenna and forming a loop.

In an embodiment of the present invention, the unit antenna may include a plurality of windings disposed on the same arrangement plane, and may further include an insulating spacer in the shape of a “ㅛ” to insulate the plurality of windings.

A method of operating a plasma generating apparatus according to an embodiment of the present invention includes: injecting a first gas into the dielectric discharge tube; providing seed charges to the inside of the dielectric discharge tube using the first gas; performing an initial discharge of the first gas from the seed charge with AC power of a first resonant frequency using an initial discharge induction coil and a first impedance matching network connected to the initial discharge induction coil; and generating a main inductively coupled plasma of the first gas with AC power having a second resonant frequency different from the first resonant frequency using a plurality of unit antennas and a second impedance matching network.

In an embodiment of the present invention, the method may further include maintaining the main inductively coupled plasma while changing the first gas to a second gas.

In one embodiment of the present invention, after the initial discharge of the first gas, a plurality of unit antennas and a second impedance matching network are used to reserve the first gas from the initial discharge with AC power near a second resonant frequency. The method may further include generating a main inductively coupled plasma.

In one embodiment of the present invention, when the preliminary main inductively coupled plasma is generated, the step of blocking the AC power of the first resonant frequency may be further included.

Atmospheric pressure plasma generating apparatus according to an embodiment of the present invention performs stable plasma generation at atmospheric pressure or higher pressure using an electrode for seed generation, an initial discharge induction coil advantageous for ignition, and a main discharge induction coil module advantageous for maintaining discharge can do.

1 is a conceptual diagram illustrating an application example of an atmospheric pressure plasma apparatus according to an embodiment of the present invention.
2A is a conceptual diagram illustrating an initial discharge operation of an atmospheric pressure plasma apparatus according to an embodiment of the present invention.
2B is a conceptual diagram illustrating a main discharge operation of an atmospheric pressure plasma apparatus according to an embodiment of the present invention.
3 is a schematic diagram illustrating the atmospheric pressure plasma apparatus of FIG. 2A as a circuit.
FIG. 4 is a conceptual diagram illustrating voltage distribution applied to an initial discharge induction coil module in an initial discharge operation of the atmospheric pressure plasma apparatus of FIG. 2A .
FIG. 5 is a conceptual diagram illustrating voltage distribution applied to a main discharge induction coil module in a main discharge operation of the atmospheric pressure plasma apparatus of FIG. 2B .
6 is a plan view illustrating an arrangement relationship of unit antennas of a main discharge induction coil module according to an embodiment of the present invention.
7 is a plan view illustrating a unit antenna of a main discharge induction coil module according to an embodiment of the present invention.
8 is a cross-sectional view illustrating an insulation state of unit antennas of a main discharge induction coil module according to an embodiment of the present invention.
9 is a cut-away perspective view illustrating a disposition relationship between a first electrode and a second electrode according to an embodiment of the present invention.
10 is a circuit diagram illustrating a DC power supply according to another embodiment of the present invention.
11 is a circuit diagram illustrating the high voltage pulse generator of FIG. 10 .
12 is a cross-sectional view illustrating a main discharge induction coil module of an atmospheric pressure plasma generating apparatus according to another embodiment of the present invention.
13 is a plan view illustrating an arrangement relationship of unit antennas of the main discharge induction coil module of FIG. 12 .
14 is a diagram illustrating an equivalent circuit for explaining an initial discharge mode of the atmospheric pressure plasma generating apparatus of FIG. 12 .
15 is a diagram illustrating an equivalent circuit for explaining a main discharge mode of the atmospheric pressure plasma generating apparatus of FIG. 12 .
16 is a timing diagram illustrating an initial discharge mode and a main discharge mode of the atmospheric pressure plasma generator of FIG. 12 .
17 is a conceptual diagram illustrating the plasma generating apparatus according to FIG. 2A.
18 is a conceptual diagram illustrating a plasma generating apparatus according to another embodiment of the present invention.
19 is a conceptual diagram illustrating a plasma generating apparatus according to another embodiment of the present invention.
FIG. 20 is a conceptual diagram for explaining discharge of the plasma generating device of FIG. 19 .
21 is a timing diagram illustrating the signal of FIG. 19 .
22 is a flowchart illustrating a method of operating the plasma generating apparatus of FIG. 19 .
23 is a conceptual diagram illustrating a plasma generating apparatus according to another embodiment of the present invention.
24 to 28 show an initial discharge induction coil module connected to a first RF power source according to embodiments of the present invention.
29 shows a main discharge induction coil module connected to a second RF power source according to another embodiment of the present invention.
30 is a circuit diagram illustrating a full-bridge inverter used in the first inverter or the second inverter.
31 is a circuit diagram illustrating a half-bridge inverter according to an embodiment of the present invention.
32 is a conceptual diagram illustrating a seed charge generator according to another embodiment of the present invention.
33 to 36 are conceptual views illustrating a high voltage pulse generator according to still another exemplary embodiment of the present invention.
37 is a plan view illustrating a unit antenna of a main discharge induction coil module according to another embodiment of the present invention.

A plasma generating apparatus according to an embodiment of the present invention includes a pair of electrodes disposed in a dielectric discharge tube, an initial discharge induction coil module, and a main discharge induction coil module. The initial discharge induction coil module and the main discharge induction coil module are connected in parallel to an RF power source, and the RF power source selectively provides RF power to the initial discharge induction coil module or the main discharge induction coil module according to a resonance frequency.

The initial discharge module has an antenna advantageous for ignition, and the main discharge module has an antenna characteristic for maintaining discharge. The initial discharge module and the main discharge module connected in parallel have different impedance characteristics depending on the driving frequency. The initial discharge module has a first resonant frequency, and the main discharge module has a second resonant frequency. When the current flows at the first resonant frequency, the current mainly flows to the initial discharge module. The non-resonant route has a relatively high impedance at the first resonant frequency, so that a relatively small amount of current flows. When the current flows at the second resonant frequency, the current mainly flows to the main discharge module. Even if there are three or more discharge modules, if a different resonant frequency is given to each discharge module, a current can be provided to a desired discharge module. Accordingly, the present invention can perform impedance matching in a wide real resistance range, implement a wide discharge control range (flow rate, power, pressure), and change the discharge function by switching the current in the discharge module for various purposes. have.

The pair of electrodes are respectively disposed on the upper and lower portions of the initial discharge induction coil of the initial discharge module to apply a DC voltage at atmospheric pressure to perform the initial discharge by applying an electrostatic vertical electric field (E_ig) to the central axis of the dielectric discharge tube and generate a seed charge.

The initial discharge induction coil module is disposed between the pair of electrodes and includes the initial discharge induction coil and an initial discharge capacitor connected in series with the initial discharge induction coil. The main discharge module and the initial discharge module are connected in parallel. The initial discharge induction coil module has a first resonant frequency, and receives RF power of the first resonant frequency from an RF power source in an initial discharge mode to perform initial discharge. The main discharge module does not discharge due to the high impedance at the first resonant frequency. The plasma by the initial discharge induction coil transitions from the capacitive coupling mode (or E mode) to the inductive coupling mode (or H mode). In the capacitive coupling mode (or E mode), the initial discharge induction coil generates a high potential difference at both ends of the initial discharge induction coil at a first resonant frequency to generate a vertical electric field (E_z) in the direction of the central axis of the dielectric discharge tube. can After transition to the inductive coupling mode (or H mode), the plasma real resistance increases and the first current flowing through the initial discharge induction coil decreases.

The main discharge module includes unit antennas arranged to be spaced apart from the initial discharge induction coil and connected to each other in series on a plurality of arrangement planes, a first main capacitor and a second main capacitor respectively arranged at both ends of the unit antennas. ; and an auxiliary capacitor connected in series between the unit antennas. The main discharge module and the initial discharge module are connected in parallel. The main discharge module has a second resonant frequency. When the initial discharge induction coil makes a transition from the capacitive coupling mode (or E mode) to the inductive coupling mode (or H mode), the RF power source changes the driving frequency from the first resonant frequency to the second resonant frequency. At the same time, the DC voltage is removed from the pair of electrodes. Accordingly, the initial discharge module does not perform a discharge because current does not flow due to the high impedance, and the main discharge module flows due to the low impedance and stably generates an inductively coupled plasma.

Hereinafter, preferred embodiments of the present invention will be described in 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 introduced herein are provided so that the disclosed subject matter may be thorough and complete, and that the spirit of the present invention may be sufficiently conveyed to those skilled in the art. In the drawings, components are exaggerated for clarity. Parts indicated with like reference numerals throughout the specification indicate like elements.

1 is a conceptual diagram illustrating an application example of an atmospheric pressure plasma apparatus according to an embodiment of the present invention.

Referring to FIG. 1 , the substrate processing apparatus 10 includes a substrate holder 93 inside a vacuum container 92 , and a deposition process, an etching process, and a deposition process on a substrate 94 disposed on the substrate holder 93 , A diffusion process or an ion implantation process may be performed. The vacuum vessel 92 is exhausted by the vacuum pump 95 , and the exhaust gas is purified through the atmospheric pressure plasma generating device 100 and discharged to the outside. The exhaust gas contains pollutants such as fine particles, toxic gases, and greenhouse gases.

The exhaust gas is purified through a gas scrubber and then discharged. The gas scrubber includes a combustion type or a plasma type.

The atmospheric discharge plasma method includes a high voltage flat plate plasma method, an arc torch method, and an induction heating plasma method. In the case of a high-voltage plate-type plasma, it has a high discharge holding capacity, but it is difficult to form a low plasma density and high temperature condition at a high operating pressure. Therefore, the effect of removing harmful substances by thermochemical decomposition is low.

On the other hand, a high-temperature plasma such as an arc torch provides a high reaction temperature, but since the processing gas is not directly injected into the plasma, the decomposition efficiency is reduced, and the durability of the electrode for arc generation is weak.

The atmospheric pressure plasma apparatus according to an embodiment of the present invention may implement a high plasma density (10^16/cm^3) and a high gas temperature (3000 degrees Celsius) by using an inductively coupled plasma at a pressure of 100 Torr or more. Accordingly, the atmospheric pressure plasma apparatus may be disposed at the rear end of the vacuum pump to decompose and process the harmful gas flowing in the gas mixed with tens of slm (Standard liter per Minute) or more under atmospheric pressure. The harmful gas may be CxFy or SxFy gas. The present invention can perform inductively coupled discharge at atmospheric pressure for CxFy gas, which is usually difficult to discharge at atmospheric pressure. Atmospheric pressure plasma apparatus according to an embodiment of the present invention can be used in a process such as CO2 reforming (CO2 reforming).

2A is a conceptual diagram illustrating an initial discharge operation of an atmospheric pressure plasma apparatus according to an embodiment of the present invention.

2B is a conceptual diagram illustrating a main discharge operation of an atmospheric pressure plasma apparatus according to an embodiment of the present invention.

3 is a schematic diagram illustrating the atmospheric pressure plasma apparatus of FIG. 2A as a circuit.

FIG. 4 is a conceptual diagram illustrating voltage distribution applied to an initial discharge induction coil module in an initial discharge operation of the atmospheric pressure plasma apparatus of FIG. 2A .

FIG. 5 is a conceptual diagram illustrating voltage distribution applied to a main discharge induction coil module in a main discharge operation of the atmospheric pressure plasma apparatus of FIG. 2A .

6 is a plan view illustrating an arrangement relationship of unit antennas of a main discharge induction coil module according to an embodiment of the present invention.

7 is a plan view illustrating a unit antenna of a main discharge induction coil module according to an embodiment of the present invention.

8 is a cross-sectional view illustrating an insulation state of unit antennas of a main discharge induction coil module according to an embodiment of the present invention.

9 is a cut-away perspective view illustrating a disposition relationship between a first electrode and a second electrode according to an embodiment of the present invention.

2 to 9 , the atmospheric pressure plasma generating apparatus 100 includes a dielectric discharge tube 140 ; An initial discharge induction coil 120 that surrounds the dielectric cylindrical tube 140 and has a plurality of windings to generate an atmospheric pressure initial discharge and is connected in series with the initial discharge induction coil 120 to provide a first resonant frequency fa The initial discharge induction coil module 102 including the initial discharge capacitors (122a, 122b); a first electrode 114 and a second electrode 116 respectively disposed above and below the initial discharge induction coil 120 to provide an initial discharge seed; a DC power supply 112 for applying a DC high voltage between the first electrode 114 and the second electrode 116; a main discharge induction coil module 103 for generating a main inductively coupled plasma by receiving the initial discharge generated by the initial discharge induction coil module 102 having a second resonant frequency fb; and an RF power supply 150 that provides RF power to the initial discharge induction coil module 102 and the main discharge induction coil module 103 connected in parallel and changes a driving frequency.

The main discharge induction coil module 103 is disposed to be spaced apart from the initial discharge induction coil 120 and disposed on a plurality of arrangement planes perpendicular to the central axis of the dielectric discharge tube 140 , respectively, and connected in series with each other. a plurality of unit antennas 132; a first main capacitor 133a and a second main capacitor 133b respectively disposed at both ends of the unit antennas 132; and auxiliary capacitors 134 connected in series between the unit antennas 132, respectively.

The RF power source 150 induces an initial discharge in the initial discharge induction coil 120 at the first resonant frequency fa with the help of the DC high voltage. The RF power source 150 performs main discharge by changing the driving frequency from the first resonant frequency fa to the second resonant frequency fb.

Atmospheric pressure inductively coupled plasma is difficult to generate ignition (or initial discharge) due to the low induced electric field. Therefore, for a stable initial discharge, DC discharge is assisted by the first electrode 114 and the second electrode 116 . On the other hand, DC discharge is difficult to form a high plasma density. The electrode disposed outside the dielectric discharge tube damages the dielectric discharge tube 140 by the high electric field E_ig.

The initial discharge induction coil 120 generates an initial inductively coupled plasma with the aid of a seed charge by DC discharge. For this, a strong electrostatic vertical electric field E_z in the central axis direction of the dielectric discharge tube 140 is required. This strong electrostatic vertical electric field (E_z) depends on the structure of the initial discharge induction coil. The electrostatic vertical electric field E_z of the initial discharge induction coil 120 may generate a capacitive coupling mode. The electrostatic vertical electric field E_z may be generated by a high potential difference Va applied to both ends of the initial discharge induction coil. The electrostatic vertical electric field E_z may be proportional to the inductance La of the initial discharge induction coil 120 . However, if the inductance La of the initial discharge induction coil 120 is too large, the power of the RF power source 150 is not efficiently transferred to the load (initial discharge induction coil) due to the high impedance. Accordingly, the initial discharge capacitors 122a and 122b are connected in series with the initial discharge induction coil 120 to provide a first resonant frequency fa. When the RF power source 150 operates at the first resonant frequency, the imaginary part of the impedance Za viewed from the output terminal of the RF power source to the initial discharge induction coil 120 may be removed. Accordingly, the RF power source 150 may stably transmit the RF power to the initial discharge induction coil. In addition, since the initial discharge induction coil 120 has a high inductance, a high potential difference Va is induced at both ends of the initial discharge induction coil 120 , and the electrostatic vertical electric field E_z generates a capacitive coupling mode. can do it In the capacitive coupling mode, a streamer discharge is locally formed in the central axis direction of the dielectric discharge tube 140 .

When plasma is sufficiently generated by the capacitive coupling mode, an induced electric field E_a_ind in the azimuth direction is generated by the first current Ia flowing through the initial discharge induction coil 120 . The plasma transitions from the capacitive coupling mode to the inductive coupling mode by the inductive electric field E_a_ind. In the inductive coupling mode by the initial discharge induction coil 120 , plasma is entirely generated in the dielectric discharge tube 140 . In the inductive coupling mode, the first current Ia flowing through the initial discharge induction coil and the potential difference Va across both ends of the initial discharge induction coil are reduced compared to the capacitive coupling mode.

However, in the inductive coupling mode by the initial discharge induction coil 120 , a high potential difference is still maintained at both ends of the initial discharge induction coil due to the high inductance La of the initial discharge induction coil 120 . Accordingly, a plasma sheath is formed between the plasma having a constant plasma potential and the initial discharge induction coil 120 , and ions pass through the plasma sheath to the dielectric discharge tube 120 . ) is accelerated to the inner wall of Accordingly, the dielectric discharge tube 120 is damaged by heat and the discharge efficiency is reduced.

In the present invention, in order to overcome this problem, an initial discharge induction coil 120 optimized for initial discharge and a main discharge induction coil module 103 that suppresses thermal damage of the dielectric discharge tube and increases discharge efficiency are used. In the initial discharge step, RF power is introduced into the initial discharge induction coil 120 to generate a transition from the capacitive coupling mode to the inductive coupling mode. The main discharge induction coil module 103 uses a large amount of charged particles generated by the initial discharge induction coil 120 to directly generate plasma in the inductive coupling mode without going through the capacitive coupling mode.

The main discharge induction coil module 103 has electrical characteristics and discharge characteristics different from those of the initial discharge induction coil module 102 . The main discharge induction coil module 103 includes a plurality of unit antennas 132 constituting the main discharge induction coil module. The antennas 132 are arranged on different arrangement planes, stacked on each other, and arranged to surround the dielectric discharge tube.

The main discharge induction coil module 103 is difficult to operate alone without the initial discharge induction coil. However, after the initial discharge induction coil transitions to the inductive coupling mode, the first current Ia flowing in the initial discharge induction coil 120 is removed, and at the same time, the second current flows in the main discharge induction coil module 103 . (Ib) flows. The main discharge induction coil module 103 can stably discharge directly in the inductive coupling mode without going through the capacitive coupling mode. The second potential difference Vb applied to each of the unit antennas 132 is smaller than the potential difference Va applied to both ends of the initial discharge induction coil 120 by voltage division. The sum Lb of the inductances of the unit antennas 132 is greater than the inductance La of the initial discharge induction coil 120 . Accordingly, the intensity of the induced electric field E_b_ind is large and the potential difference of the plasma sheath is small, so that thermal damage of the dielectric discharge tube 140 is suppressed, and discharge efficiency is increased.

The main discharge induction coil module 103 is a plurality of units arranged to be spaced apart from the initial discharge induction coil, respectively arranged on a plurality of arrangement planes perpendicular to the central axis of the dielectric discharge tube 140 and connected in series to each other. antennas 132; a first main capacitor 133a and a second main capacitor 133b respectively disposed at both ends of the unit antennas; and auxiliary capacitors 134 connected in series between the unit antennas, respectively. The main discharge induction coil module 103 has a second resonant frequency fb and performs voltage distribution in proportion to the number of the unit antennas 132 . Accordingly, thermal damage to the dielectric discharge tube is suppressed, and the discharge efficiency is increased.

The RF power source 150 may change a driving frequency, and may selectively supply RF power to the initial discharge induction coil module 102 and the main discharge induction coil module 103 connected in parallel with each other. At the first resonant frequency fa, the RF power source 150 mainly supplies power to the initial discharge induction coil module 102 . Meanwhile, at the second resonant frequency fb, the RF power source 150 mainly supplies power to the main discharge induction coil module 103 .

The dielectric discharge tube 140 may be a cylindrical dielectric discharge tube. Specifically, the material of the dielectric discharge tube 140 may be ceramic, sapphire, or quartz. The ceramic may be alumina or AlN. The outer diameter of the dielectric discharge tube 140 may be several centimeters to several tens of centimeters. The inner diameter of the dielectric discharge tube 140 may be smaller than the outer diameter by several millimeters to several tens of millimeters. The length of the dielectric discharge tube 140 may be several centimeters to several meters. Both ends of the dielectric discharge tube 140 may be sealed by being coupled to the upper flange 142 and the lower flange 144 , respectively. The lower flange 144 may receive the exhaust gas of the substrate processing apparatus 10 as a process gas.

Referring to FIG. 9 , the initial discharge induction coil 120 may maximize the number of turns per unit length in the longitudinal direction of the dielectric discharge tube 120 . The initial discharge induction coil 120 may be a solenoid coil having a multilayer structure. Specifically, the initial discharge induction coil 120 has a solenoid shape and may be wound in multiple layers. The initial discharge induction coil 120 may have a three-layer structure of an inner solenoid coil 120a, an intermediate solenoid coil 120b, and an outer solenoid coil 120c. The inner solenoid coil 120a may have four turns surrounding the dielectric discharge tube. The intermediate solenoid coil 120b may have 4 turns surrounding the inner solenoid coil. The outer solenoid coil 120c may have three turns surrounding the intermediate solenoid coil 120b. The initial discharge induction coil 120 may be wound to constructively interfere with a magnetic field therein. For example, the inductance La of the initial discharge induction coil 120 may be 8uH. The initial discharge induction coil 120 is formed of a copper pipe, and a refrigerant may flow inside the initial discharge induction coil. A cross section of a pipe constituting the initial discharge induction coil may be circular.

The initial discharge capacitors 122a and 122b may be connected to at least one of both ends of the initial discharge induction coil. The initial discharge capacitors 122a and 122b and the initial discharge induction coil 120 may be connected in series to provide a first resonant frequency fa. The capacitance Ca of the first initial discharge capacitor 122a may be the same as the capacitance Ca of the second initial discharge capacitor 122b.

The first resonant frequency fa may be 3.3 MHz. The first resonant frequency fa may be defined by the equivalent capacitance C′a of the initial discharge capacitors 122a and 122b and the inductance La of the initial discharge induction coil 120 . The initial discharge capacitors 122a and 122b may be disposed at one of both ends of the initial discharge induction coil.

The DC power source 112 may generate a high voltage DC pulse. The high voltage DC pulse may be a negative DC high voltage and a positive DC high voltage. The DC power supply 112 may generate a high voltage pulse of several tens of kHz. The negative DC high voltage may be negative tens of kV, and the positive DC high voltage may be positive tens of kV.

The pair of electrodes 114 and 116 includes a first electrode 114 and a second electrode 116 respectively disposed above and below the initial discharge induction coil 120 . The first electrode 114 may be in the form of a square plate that is charged with a positive DC high voltage and is closely attached to the dielectric discharge tube.

The first electrode 114 is disposed above the initial discharge induction coil 120 in contact with the outer wall of the dielectric discharge tube 140 and receives the positive DC high voltage. The first electrode 114 may have a rectangular shape.

The second electrode 116 is disposed in contact with the outer wall of the dielectric discharge tube 120 under the initial discharge induction coil 120 and receives the negative DC high voltage. The second electrode 116 may have a “C” shape to surround the dielectric discharge tube. The second electrode may have a larger area than the first electrode to generate electrons. The second electrode 116 may be disposed to surround the dielectric discharge tube with a band-shaped conductor. The second electrode 116 may be heated by an induced electric field E_a_ind by the initial discharge induction coil or an induced electric field E_b_ind by the unit antennas. Accordingly, a perfect loop may not be formed so that an eddy current caused by the induced electric fields E_a_ind and E_b_ind does not flow, and may have a “C” shape. The second electrode may be in the form of a band that is charged with a high negative DC voltage and is closely attached to the dielectric discharge tube. In addition, the second electrode may be formed to be meandering so that the induced electric field in the azimuth direction does not flow or may include a plurality of slits extending in the direction of the central axis of the cylinder.

Voltages applied to the first electrode 114 and the second electrode 116 may have opposite signs and have the same absolute value. The DC power supply 112 for applying a DC high voltage to the first electrode 114 and the second electrode 116 may apply a level of 30 kV at atmospheric pressure. In this case, a "C" shape is formed on the vertical streamer and the second electrode 116 in the vertical direction (the central axis direction of the dielectric discharge tube) connecting the first electrode 114 and the second electrode 116 . of streamers. When the second electrode 116 forms a perfect loop, the first current flowing through the initial discharge induction coil 120 may generate an eddy current in the second electrode 116 to heat it. Accordingly, the second electrode 116 may be cut while securing a sufficient area to suppress eddy currents or may have a slit in a vertical direction.

The distance between the first electrode 114 and the initial discharge induction coil 120 or the gap between the second electrode 116 and the initial discharge induction coil 120 is a parasitic discharge and an induced electric field by high voltage at atmospheric pressure. It may be sufficiently spaced apart to suppress induction heating by Specifically, a distance between the first electrode 114 and the initial discharge induction coil 120 or a distance between the second electrode 116 and the initial discharge induction coil 120 may be several cm or more. Preferably, the distance may be 1 cm or more.

The RF power source 150 may output RF power. The RF power source 150 may convert commercial AC power into RF power and deliver it to a load. For example, the RF power may have a frequency of several hundreds of kHz to several tens of MHz and a power of several kW or more. The RF power source 150 may include a rectifier, an inverter, and a controller. The rectifier may convert commercial AC power into DC power. The inverter may receive the DC power and convert it into RF power in response to switching signals of the controller. The controller may control the switching signals to control the driving frequency and power. The RF power may perform impedance matching at the first resonant frequency fa or the second resonant frequency fb by changing the driving frequency. The first resonant frequency fa and the second resonant frequency fb may be spaced apart from each other by 0.2 MHz or more. When the first resonant frequency fa is within 0.2 MHz of the second resonant frequency fb, impedances in the two current directions are similar, so that power switching may be unstable. The first resonant frequency fa may be greater than the second resonant frequency fb.

The first detection sensor 152 may detect a current or voltage flowing through the initial discharge induction coil 120 . The second detection sensor 154 may detect a current or voltage flowing through the main discharge induction coil module 103 . The RF power source 150 may detect a transition from the capacitive coupling mode to the inductive coupling mode using the output of the first detection sensor 152 and change the driving frequency from the first resonant frequency to the second resonant frequency. .

Referring to FIG. 6 , the main discharge induction coil module 103 includes a plurality of unit antennas, auxiliary capacitors 134 respectively disposed between the plurality of unit antennas 132 , and all of the plurality of unit antennas. and a first main capacitor 133a and a second main capacitor 133b respectively disposed at both ends of the . A cross-section of a coil constituting the unit antenna 132 may be rectangular. The unit antennas 132 may be arranged at intervals of 90 degrees in a clockwise direction. Accordingly, terminals electrically connecting the unit antennas 132 may not interfere with each other.

7 and 8 , the rectangular cross-section increases the contact area with the dielectric discharge tube 140 to improve heat exchange efficiency, thereby cooling the dielectric discharge tube 140 . When the main discharge is performed, the plasma may transfer energy to the dielectric discharge tube 140 to heat it to hundreds of degrees Celsius or more. An increase in the temperature of the dielectric discharge tube 140 may cause material degradation or damage. The unit antenna 132 is cooled by flowing a refrigerant therein. Since the coil having a circular cross section is in line contact with the dielectric discharge tube 140 , it is difficult to efficiently cool the dielectric discharge tube 140 . Meanwhile, the cooling efficiency of the coil having a rectangular cross section is increased through surface contact with the dielectric discharge tube 140 . In order to stably maintain contact between the inner coil of the unit antenna 132 and the dielectric discharge tube 140 , the inner coil is tightened to decrease a radius. Experimentally, breakage of the dielectric discharge tube 140 was found at an RF power of 5 kW or more in the case of a circular cross-section coil. However, in the case of the rectangular cross-section coil, no breakage of the dielectric discharge tube 140 was found even at 8 kW.

The unit antenna 132 may include: a first antenna 132a disposed in contact with the dielectric discharge tube 140 in an arrangement plane perpendicular to the central axis of the dielectric discharge tube and forming a loop; a second antenna (132b) continuously connected to the first antenna (132a) and disposed to surround the first antenna and forming a loop; and a third antenna 132c continuously connected to the second antenna 132b, disposed to surround the second antenna, and forming a loop.

The unit antenna 132 has a rectangular cross section, and the first antenna 132a is in close contact with the dielectric discharge tube to cool the dielectric discharge tube. The first antenna 132a and the second antenna 132b may be connected by a "U"-shaped first connection part 32a. The second antenna 132b and the third antenna 132c may be connected to each other by a second connector 32b having a “U” shape.

In order to bring the first antenna 132a into contact with the dielectric discharge tube 140 , clamps 35 may be disposed to bring both ends of the first antenna 132a into close contact with each other. The clamp 35 may be a cable tie.

The unit antenna 132 includes a plurality of windings disposed on the same arrangement plane, and the insulating spacer 36 insulates the plurality of windings and may have a “ㅛ” shape. Each winding constituting the unit antenna 132 may be electrically insulated by an insulating spacer 36 and maintain a constant interval. The insulating spacer 36 may insulate between adjacent unit antennas 132 . The insulating spacer has a “ㅛ” shape, and the second antenna 132b may be inserted into the recessed portion 36a.

At least a portion of the first antenna 132a may be molded with a ceramic paste. The ceramic mold 37 surrounding at least a portion of the first antenna 132a may be in thermal contact with the dielectric discharge tube. Accordingly, when the refrigerant flows through the unit antenna, the cooled unit antenna may cool the ceramic mold 37 , and the ceramic mold 37 may indirectly cool the dielectric discharge tube 140 .

The electrostatic capacity 2C1 of the first main capacitor 133a is equal to the electrostatic capacity of the second main capacitor 133b, and the electrostatic capacity of the first main capacitor 133a is the electrostatic capacity of the auxiliary capacitor 134 . It may be twice the capacity (C1).

The second resonant frequency fb may be given by the sum Lb of the inductances of the plurality of unit antennas and the equivalent capacitance C′b of the capacitors 133a, 133b, and 134 .

A first voltage drop Va induced in the initial discharge induction coil 120 at the first resonant frequency fa is a second voltage drop Vb induced in the unit antenna at the second resonant frequency fb. can be larger The second voltage drop (Vb) is the second resonance frequency (fb), the second current (Ib). and the inductance L1 of the unit antenna. The first voltage drop Va is a first resonant frequency fa, a first current Ia. and the inductance La of the initial discharge induction coil.

A sum Lb of inductances of the plurality of unit antennas may be greater than an inductance La of the initial discharge induction coil.

10 is a circuit diagram illustrating a DC power supply according to another embodiment of the present invention.

11 is a circuit diagram illustrating the high voltage pulse generator of FIG. 10 .

10 and 11 , the DC power source 112 includes an AC-DC converter 1120 for converting commercial power into a DC voltage (Vin); a high voltage pulse generator 1122 receiving the DC voltage Vin and generating a positive DC high voltage pulse and a negative DC high voltage pulse; and a controller 1124 for controlling the high voltage pulse generator.

The high voltage pulse generator 1122 includes: a first transformer 1222a including a primary coil receiving the DC voltage of the AC-DC converter and a secondary coil generating a positive DC high voltage pulse; a first power transistor 1222b connected to the primary coil of the first transformer; a second transformer 1222c including a primary coil receiving the DC voltage of the AC-DC converter and a secondary coil generating a negative DC high voltage pulse; and a second power transistor 1222d connected to the primary coil of the second transformer. The controller 1124 controls the gates of the first power transistor 1222b and the second power transistor 1222d. One end of the secondary coil of the first transformer 1222a outputs a positive DC high voltage pulse, and the other end of the secondary coil of the first transformer 1222a is grounded. One end of the secondary coil of the second transformer 1222c outputs a negative DC high voltage pulse, and the other end of the secondary coil of the second transformer 1222c is grounded.

The DC voltage Vin may be a DC voltage of 12V to 24V. The controller 1124 synchronizes and controls on-time and repetition frequencies of the first power transistor 1222b and the second power transistor 1122d. The DC high voltage pulse may be several tens of kV, and the repetition frequency may be several tens of kHz.

12 is a cross-sectional view illustrating a main discharge induction coil module of an atmospheric pressure plasma generating apparatus according to another embodiment of the present invention.

13 is a plan view illustrating an arrangement relationship of unit antennas of the main discharge induction coil module of FIG. 12 .

14 is a diagram illustrating an equivalent circuit for explaining an initial discharge mode of the atmospheric pressure plasma generating apparatus of FIG. 12 .

15 is a diagram illustrating an equivalent circuit for explaining a main discharge mode of the atmospheric pressure plasma generating apparatus of FIG. 12 .

16 is a timing diagram illustrating an initial discharge mode and a main discharge mode of the atmospheric pressure plasma generator of FIG. 12 .

12 to 16 , the atmospheric pressure plasma generating apparatus 200 includes a dielectric discharge tube 140 ; An initial discharge induction coil 120 that surrounds the dielectric cylindrical tube 140 and has a plurality of windings to generate an atmospheric pressure initial discharge and is connected in series with the initial discharge induction coil 120 to provide a first resonant frequency fa The initial discharge induction coil module 102 including the initial discharge capacitors (122a, 122b); a first electrode 114 and a second electrode 116 respectively disposed above and below the initial discharge induction coil 120 to provide an initial discharge seed; a DC power supply 112 for applying a DC high voltage between the first electrode 114 and the second electrode 116; a main discharge induction coil module 203 for generating a main inductively coupled plasma by receiving the initial discharge generated by the initial discharge induction coil module 102 having a second resonant frequency fb; and an RF power supply 150 that provides RF power to the initial discharge induction coil module 102 and the main discharge induction coil module 203 connected in parallel and changes a driving frequency.

The main discharge induction coil module 203 is disposed to be spaced apart from the initial discharge induction coil 120 and disposed on a plurality of arrangement planes perpendicular to the central axis of the dielectric discharge tube 140, respectively, and connected in series with each other. a plurality of unit antennas 232a to 232d; 332a to 332e; a first main capacitor (133a) and a second main capacitor (133b) respectively disposed at both ends of the entire unit antennas (232a to 232d; 332a to 332e); and auxiliary capacitors 134 connected in series between the unit antennas 232a to 232d; 332a to 332e, respectively.

The RF power source 150 induces an initial discharge in the initial discharge induction coil 120 at the first resonant frequency fa with the help of the DC high voltage. The RF power source 150 performs main discharge by changing the driving frequency from the first resonant frequency fa to the second resonant frequency fb.

The unit antennas 232a to 232d; 332a to 332e are disposed on different arrangement planes and may be ten. The unit antennas 232a to 232d; 332a to 332e are divided into a first group 232a to 232d including five unit antennas and a second group 332a to 332e including five other unit antennas. The unit antennas constituting the first group 232a to 232d may be disposed at intervals of 72 degrees along the azimuth direction. The unit antennas constituting the second group 332a to 332e may be disposed at intervals of 72 degrees along the azimuth direction. Accordingly, the unit antennas may not interfere for electrical connection of neighboring unit antennas.

Specifically, the equivalent capacitance C'a of the initial discharge capacitors 122a and 122b is 260 pF, the inductance La of the initial discharge induction coil is 8 uH, and the parasitic resistance Ra of the initial discharge induction coil. may be 0.5 ohms. The first resonant frequency fa may be 3.3 MHz.

The inductance of the unit antenna may be 3.5 uH, and the sum of inductances of the unit antennas may be 35 uH. In addition, the equivalent capacitance (C′b) of the capacitors 133a, 133b, and 134 constituting the main discharge induction coil module 203 may be 156 pF. The parasitic resistance Rb of the main discharge induction coil module 203 may be 2.1 ohms. The second resonant frequency fb may be 2.2 MHz.

Referring to FIG. 14 , in the initial discharge stage, the driving frequency may be 3.3 MHz, which is the first resonant frequency. In this case, the first current Ia flowing through the initial discharge induction coil module 102 is 31.5A, and the second current Ib flowing through the main discharge induction coil module 203 is 0.04A. Accordingly, the current ratio (Ia:Ib) or the impedance ratio may be 800:1. That is, in the initial discharge stage, all current flows to the initial discharge induction coil module 102 and may transition from the capacitive coupling mode to the inductive coupling mode. When the first current (Ia) or voltage flowing through the initial discharge induction coil module 102 is sensed and transitioned to the inductive coupling mode, the RF power changes the driving frequency to the second resonant frequency (fb) according to the control signal do.

Referring to FIG. 15 , in the main discharge stage, the driving frequency may be 2.2 MHz, which is the second resonance frequency. In this case, the first current Ia flowing through the initial discharge induction coil module 102 is 0.5A, and the second current Ib flowing through the main discharge induction coil module 203 is 49.5A. Accordingly, the current ratio (Ia:Ib) or the impedance ratio may be 1:100. That is, in the main discharge stage, all current flows to the main discharge induction coil module 203 . Thus, a stable plasma is maintained.

In addition, the maximum value (V2) of the potential difference (Vb) applied to both ends of the unit antenna in the main discharging step is about the maximum value (Vo) of the potential difference (Va) applied to both ends of the initial discharge induction coil in the initial discharging step. 5.2 times smaller. Accordingly, thermal damage to the dielectric discharge tube during the main discharge can be eliminated.

17 is a conceptual diagram illustrating the plasma generating apparatus according to FIG. 2A.

Referring to FIG. 17 , the plasma generating apparatus 100 includes a dielectric discharge tube 140 ; a seed charge generating unit 105 for generating seed charges in the dielectric discharge tube 140 ; An initial discharge induction coil 120 surrounding the dielectric cylindrical tube 140 and receiving the seed charge to generate an initial discharge, and a first impedance matching connected to the initial discharge induction coil 120 to provide a first resonant frequency an initial discharge induction coil module 102 comprising a network 122 ; A plurality of unit antennas 132 and the unit antennas 132 disposed to be spaced apart from the initial discharge induction coil 120, surrounding the dielectric cylindrical tube 140, and receiving the initial discharge to generate a main inductively coupled plasma ) connected to the main discharge induction coil module 103 including a second impedance matching network 133 for providing a second resonant frequency; and an RF power supply 150 for supplying power to the initial discharge induction coil module 102 and the main discharge induction coil module 103 .

The seed charge generator 105 includes a first electrode 114 , a second electrode 116 , and a DC power supply 112 for applying a DC high voltage between the first electrode 114 and the second electrode 116 . ) may be included.

DC power 112 is an AC-DC converter 1120 for converting commercial power into DC voltage (Vin); a high voltage pulse generator 1122 receiving the DC voltage Vin and generating a positive DC high voltage pulse and a negative DC high voltage pulse; and a controller 1124 for controlling the high voltage pulse generator.

The RF power source 150 may include a rectifier 151 , an inverter 156 , and a controller 158 .

2A and 17 , the initial discharge capacitors 122a and 122b are respectively disposed at both ends of the initial discharge induction coil 120 to provide impedance matching to the load while configuring a resonance circuit to perform impedance matching. can That is, the first impedance matching network 122 may include the initial discharge capacitors 122a and 122b.

In addition, the first main capacitor 133a and the second main capacitor 133b are respectively disposed at both ends of the series-connected unit antennas that perform the main discharge, and provide impedance matching to the load while configuring a resonance circuit to perform impedance matching. can be done That is, the second impedance matching network 133 may include the first main capacitor 133a and the second main capacitor 133b.

The distance d2 between the initial discharge induction coil 120 and the unit antenna 132 of the main coil induction coil module is sufficiently spaced apart to protect the second electrode 116 that generates the seed charge by DC high voltage. can For a compact structure, the second electrode 116 disposed between the initial discharge induction coil 120 and the unit antenna 132 of the main coil induction coil module 103 needs to be removed. In order to stably generate the seed charge, the seed charge generator 105 may generate the seed charge in various ways.

For example, the seed charge generator 105 may include a pair of electrodes having a DC high voltage difference. One electrode may be disposed on an outer wall of the dielectric discharge tube, and the other electrode may be disposed on a central axis of the dielectric discharge tube 140 . Accordingly, a strong electric field may be applied by a DC high voltage pulse in a radial direction of the dielectric discharge tube 140 to generate seed charges. When the second electrode 116 disposed between the initial discharge induction coil 120 and the unit antenna 132 of the main coil induction coil module is removed, the plasma generating apparatus may have a compact structure. In order to stably generate a seed charge, a plurality of electrodes may be disposed outside and/or inside the dielectric discharge tube. Specifically, the first electrode 114 may receive DC high voltage and be disposed in contact with the outer wall of the dielectric discharge tube 140 , and the second electrode may be grounded and disposed inside the dielectric discharge tube 140 . The second electrode may be grounded and perform a nozzle function for discharging the ignition gas and/or the process gas. Accordingly, an electric field may be generated in a radial direction of the dielectric discharge tube by a DC high voltage pulse, and the electric field may generate a seed charge to induce an initial discharge of the initial discharge induction coil module.

According to a modified embodiment of the present invention, the seed charge generating unit 105 includes a waveguide that receives a high frequency wave and radiates through a slit, and the ultra high frequency emitted through the slit of the waveguide is transmitted inside the dielectric discharge tube. can generate a seed charge at atmospheric pressure.

18 is a conceptual diagram illustrating a plasma generating apparatus according to another embodiment of the present invention.

Referring to FIG. 18 , the plasma generating device 200 includes a dielectric discharge tube 140 ; a seed charge generating unit 205 for generating seed charges in the dielectric discharge tube 140 ; An initial discharge induction coil 120 surrounding the dielectric cylindrical tube 140 and receiving the seed charge to generate an initial discharge, and a first impedance matching connected to the initial discharge induction coil 120 to provide a first resonant frequency an initial discharge induction coil module 102 comprising a network 122 ; A plurality of unit antennas 132 and the unit antennas 132 disposed to be spaced apart from the initial discharge induction coil 120, surrounding the dielectric cylindrical tube 140, and receiving the initial discharge to generate a main inductively coupled plasma ) connected to the main discharge induction coil module 103 including a second impedance matching network 133 for providing a second resonant frequency; and an RF power supply 150 for supplying power to the initial discharge induction coil module 102 and the main discharge induction coil module 103 .

The dielectric discharge tube 140 may be a cylindrical dielectric tube.

The seed charge generator 205 may include a first electrode 114 and a second electrode 216 disposed on the dielectric discharge tube 140 to provide a seed charge; and a DC power supply 212 for applying a DC high voltage pulse between the first electrode 114 and the second electrode 216 . The first electrode 114 may be in the form of a plate or a strip and may be disposed to be bent in contact with the outer wall of the dielectric discharge tube 140 . The second electrode 216 may be disposed on the central axis of the dielectric discharge tube 140 and may be electrically grounded. The second electrode 216 has a cylindrical shape and may additionally perform a nozzle function for spraying gas.

The DC power supply 212 may output a DC high voltage pulse (V _DC ) of several kHz to several tens of kHz. The output DC voltage of the DC power supply 112 may be several kV to several tens of kV. An electric field E_ig is generated in the radial direction of the dielectric discharge tube 140 by a DC high voltage pulse V _DC , and the electric field E_ig generates a seed charge in a state in which the ignition gas is injected, and the seed charge is An initial discharge of the ignition gas of the initial discharge induction coil module may be induced. The seed charge generator 105 includes a first electrode 114 , a second electrode 116 , and a DC power supply 112 for applying a DC high voltage between the first electrode 114 and the second electrode 116 . ) may be included.

DC power 212 is an AC-DC converter 2120 for converting commercial power into DC voltage (Vin); a high voltage pulse generator 2122 receiving the DC voltage Vin and generating a positive DC high voltage pulse and a negative DC high voltage pulse; and a controller 2124 for controlling the high voltage pulse generator.

As the electrode disposed between the initial discharge induction coil 120 and the unit antenna 132 of the main coil induction coil module is removed, a compact structure is possible. The distance d2 between the initial discharge induction coil 120 and the unit antenna 132 of the main coil induction coil module may be maintained to 3 cm or less. Also, the distance d1 between the initial discharge induction coil 120 and the first electrode may be maintained to be 3 cm or less.

The initial discharge induction coil module 102 includes the first impedance matching network 122 and the initial discharge induction coil 120 . The first impedance matching network 122 may include a pair of initial discharge capacitors 122a and 122b respectively connected to both ends of the initial discharge induction coil 120 . The initial discharge induction coil 120 may be in the form of a solenoid having a multilayer structure in order to increase inductance. The first resonant frequency fa of the initial discharge induction coil module 102 is in the range of 4 MHz to 5 MHz, and a current of several tens of amperes may flow to the initial discharge induction coil module 102 . The initial discharge induction coil 120 generates an initial discharge of gas with the help of the seed charge, and transitions from the capacitive coupling mode (or E-mode) to the inductive coupling mode (or H-mode). That is, the initial discharge plasma transitions from the streamer type capacitive coupling mode to the bulk plasma type inductive coupling mode in which plasma is entirely formed inside the dielectric discharge tube 140 .

The main discharge induction coil module 103 includes: a plurality of unit antennas 132 respectively disposed on a plurality of arrangement planes perpendicular to the central axis of the dielectric discharge tube and connected in series with each other; auxiliary capacitors 134 connected in series between the adjacent unit antennas 132, respectively; and a second impedance matching network 133 connected to the unit antennas 132 connected in series. The main discharge induction coil module 103 may generate a main inductively coupled plasma using an initial discharge of gas.

The second impedance matching network 133 may include a first main capacitor 133a and a second main capacitor 133b. Each of the first main capacitor 133a and the second main capacitor 133b is disposed at both ends of the unit antennas connected in series, respectively.

The main discharge induction coil module 103 has a second resonant frequency fb, and includes the second impedance matching network 133 to perform impedance matching to the second resonant frequency. The unit antennas 132 may have at least one turn on the same plane. The unit antennas 132 are arranged on different arrangement planes, and adjacent unit antennas are connected in series with each other through the auxiliary capacitor 134 .

The RF power source 150 includes a rectifier 151 for converting commercial AC power into DC power; an inverter 156 that receives the DC power and converts it into RF power in response to switching signals of the control unit 158; and a control unit 158 controlling the driving frequency and power by controlling the switching signals. The RF power source 150 may operate at the first resonant frequency fa during initial discharge, and may operate at the second resonant frequency fb when the main inductively coupled plasma is generated. The RF power source 150 may be a variable frequency power source. The RF power source 150 may maintain the main inductively coupled plasma by changing the ignition gas to a process gas when the main inductively coupled plasma is generated.

The rectifier 151 may convert the output of commercial AC power into DC power. The rectifier may supply DC power between the ground node GND and the power node VP. The capacitor may be connected between the ground node GND and the power node VP to discharge an AC component to the ground node.

The inverter 156 may receive the switching signal from the controller 158 and convert the DC power into the AC power in response to the switching signals. The controller 158 may control the switching signal to adjust the amount of power supplied from the inverter to the load and the driving frequency.

When there is only one RF power source, the first resonant frequency fa and the second resonant frequency fb should be sufficiently spaced apart by 0.2 MHz or more. However, it is difficult for the RF power supply to provide a stable output over a wide frequency variable range. Especially. The initial discharge is advantageous as the driving frequency is higher and the more current flows. Accordingly, both ends of the initial discharge induction coil maintain a high potential difference due to a large current and a large inductance to induce accumulation-coupled mode discharge at the first resonant frequency fa. On the other hand, the main inductively coupled plasma requires a high power of several kW or more and a low voltage drop of the unit antenna. A high-power RF power of several kW or more may operate at a second resonant frequency fb lower than the first resonant frequency fa. Accordingly, the first RF power source operating at the first resonant frequency and the second RF power source operating at the second resonant frequency may have different characteristics and may be separated from each other.

19 is a conceptual diagram illustrating a plasma generating apparatus according to another embodiment of the present invention.

FIG. 20 is a conceptual diagram for explaining the discharge of the plasma generating device of FIG. 19 .

21 is a timing diagram illustrating the signal of FIG. 19 .

22 is a flowchart illustrating a method of operating the plasma generating apparatus of FIG. 19 .

19 to 22 , the plasma generating device 300 includes a dielectric discharge tube 140 ; a seed charge generating unit 205 for generating seed charges in the dielectric discharge tube 140 ; An initial discharge induction coil 120 surrounding the dielectric cylindrical tube 140 and receiving the seed charge to generate an initial discharge, and a first impedance matching connected to the initial discharge induction coil 120 to provide a first resonant frequency an initial discharge induction coil module 102 comprising a network 122 ; A plurality of unit antennas 132 and the unit antennas 132 disposed to be spaced apart from the initial discharge induction coil 120, surrounding the dielectric cylindrical tube 140, and receiving the initial discharge to generate a main inductively coupled plasma ) connected to the main discharge induction coil module 103 including a second impedance matching network 133 for providing a second resonant frequency; and an RF power supply 350 for supplying power to the initial discharge induction coil module 102 and the main discharge induction coil module 103 .

The first RF power source 350a for inducing the initial discharge may be designed to drive a high current of several tens of amps or more at a first resonant frequency fa of several MHz or more. In addition, the second RF power source 350b for inducing the main discharge plasma may be designed to provide high power of several kW or more at a second resonant frequency fb of several MHz or less, preferably 400 kHz to 4 MHz. Specifically, the first RF power source 350a may be implemented through a half-bridge inverter circuit, and the second RF power source 350b may be implemented through a full-bridge inverter circuit. In addition, the first RF power source 350a may be controlled to operate at a fixed first resonant frequency. In addition, the second RF power source 350b may operate near the second resonant frequency by controlling the driving frequency to adjust the amount of power or the impedance.

The RF power supply 350 includes: a first RF power supply 350a that provides AC power to the initial discharge induction coil module 102 and operates at the first resonant frequency fa; and a second RF power source 350b that provides AC power to the main discharge induction coil module 103 and operates at the second resonant frequency fb.

The first RF power source 350a includes: a first rectifier 351a for converting AC power into DC power; a first inverter (356a) receiving the DC power of the first rectifier (351a) and providing AC power of a first resonant frequency (fa) to the initial discharge induction coil module (102); and a first control unit 358a for controlling the output of the first inverter 356a. The first RF power source 350a may operate at a first resonant frequency fa.

The second RF power source 350b includes a second rectifier 351b for converting AC power into DC power; a second inverter (356b) receiving the DC power from the second rectifier (351b) and providing AC power of a second resonant frequency (fb) to the main discharge induction coil module (103); and a second controller 358b for controlling the output of the second inverter 356b. The second RF power source 350b may operate while being variable around the second resonant frequency fb.

A method of operating a plasma generating apparatus according to an embodiment of the present invention includes: injecting a first gas into the dielectric discharge tube 140 (S210); providing seed charges to the inside of the dielectric discharge tube using the first gas (S220); Initial discharge of the first gas is performed from the seed charge with AC power at a first resonance frequency fa using the initial discharge induction coil 120 and the first impedance matching network 122 connected to the initial discharge induction coil. step (S230); and main inductive coupling of the first gas from the initial discharge with AC power of a second resonant frequency fb different from the first resonant frequency using a plurality of unit antennas 132 and a second impedance matching network 133 and generating plasma (S260).

In the step of injecting the first gas into the dielectric discharge tube 140 ( S210 ), the first gas is to be injected into the upper portion of the dielectric discharge tube 140 through the second electrode 216 performing a nozzle function. can The pressure of the dielectric discharge tube 140 may be several Torr or more, and preferably, atmospheric pressure or more. The first gas may be argon gas, nitrogen gas, hydrogen-containing gas, carbon dioxide gas, or a combination thereof, which is advantageous for ignition.

In the step of providing the seed charge using the first gas to the inside of the dielectric discharge tube 140 ( S220 ), the seed charge may be formed using the seed charge generator 205 . For example, the first electrode 114 is attached to the outer wall of the dielectric discharge tube 140 , and the second electrode 216 is inserted into the central axis of the dielectric discharge tube 140 to face the first electrode. can The second electrode 216 may be grounded and perform a nozzle function for spraying the first gas or the second gas. In a state in which the second electrode 216 is grounded, the first electrode 114 may generate a seed charge by a _{DC high voltage pulse V DC .} The second electrode 216 may act as a cathode, and the first electrode 114 may act as an anode. The DC high voltage pulse (V _DC ) may have a pulse frequency of several tens of kHz and a voltage of several tens of kV.

In the step of performing the initial discharge of the first gas from the seed charge ( S230 ), the AC power PO1 of the first resonant frequency fa may be provided to the initial discharge induction coil module 102 . When the AC power PO1 of the first resonance frequency is applied to the initial discharge induction coil module 102 while the DC high voltage pulse V _{DC is applied, both ends of the initial discharge induction coil 120 have a large inductance.} due to the high potential difference. remind A vertical electric field E_z may be generated in the direction of the central axis of the dielectric discharge tube 140 . The vertical electric field E_z may generate a capacitively coupled mode (or E-mode) plasma. The capacitive coupling mode may transition to an inductive coupling mode (or H mode). Accordingly, the current Ia flowing through the initial discharge induction coil 120 decreases due to an increase in the actual resistance of the initial discharge plasma as the load, and the AC power PO1 of the first resonance frequency is the actual resistance of the initial discharge plasma as the load. It can be increased by increasing resistance. The mode transition may be detected by monitoring the AC power PO1 or the current Ia of the first resonant frequency. The first detection sensor 152 disposed at the output terminal of the first RF power may be used to detect the current Ia. The first detection sensor 152 may be a Hall sensor that detects a current. Alternatively, the first detection sensor 152 is disposed at the input terminal of the first inverter 356a to detect the input current of the first inverter 356a to monitor the AC power using the information of the DC power and the input current. can

The DC high voltage pulse V _DC may be removed after the mode transition or may be removed even before the mode transition of the initial discharge to stop supplying the seed charge ( S240 ).

A preliminary main inductively coupled plasma of the first gas may be generated from the initial discharge with AC power near a second resonant frequency using a plurality of unit antennas and a second impedance matching network (S250).

The main discharge induction coil module 103 may include the plurality of unit antennas 132 , an auxiliary capacitor 134 connected in series between neighboring unit antennas, and a second impedance matching network 133 . The main discharge induction coil module 103 may have a capacitive coupling mode (or E-mode) and an inductive coupling mode (or H-mode) similar to the initial discharge induction coil module. The second RF power source 350b may output AC power P02.

In order for the main discharge to stably transition to the inductively coupled mode (or H-mode), the second RF power source 350b may initially supply AC power P1 of an initial frequency near the second resonant frequency fb. can The initial frequency may be tens to hundreds of kHz greater than the second resonant frequency. Accordingly, the potential difference applied to both ends of the unit antenna of the main discharge induction coil module 103 at the initial frequency may be greater than the potential difference applied at the second resonant frequency fb. A potential difference applied to both ends of the unit antenna at the initial frequency may stably generate a preliminary main inductively coupled plasma using charges generated by the initial discharge. The AC power P1 of the initial frequency may be supplied after or simultaneously with the E-mode transition of the initial discharge.

Next, in the step of generating the main inductively coupled plasma of the first gas (S260), the second RF power source 350b converts the AC power P2 of the second resonant frequency fb to the main discharge induction coil module 103. can be supplied to That is, the second RF power source 350b may supply the AC power P2 of the second resonance frequency to the main discharge induction coil module 103 by changing the frequency. Accordingly, the AC power P2 of the second RF power source 350b increases by impedance matching, and the main discharge induction coil module 103 can stably operate the inductive coupling mode (or H-mode). . As the current Ib flowing through the main discharge induction coil module 103 is changed to the second resonant frequency, it may increase by impedance matching. Accordingly, a stable main inductively coupled plasma using the first gas is maintained. The second detection sensor 154 disposed at the output terminal of the second RF power may be used to detect the current Ib. The second detection sensor 154 may be a Hall sensor that detects a current. Alternatively, the second detection sensor 154 is disposed at the input terminal of the second inverter 356b to detect the input current of the second inverter 356b to monitor the AC power using the information of the DC power and the input current. can

Subsequently, when the main inductively coupled plasma is generated, the AC power of the first resonant frequency may be cut off ( S270 ). The interruption of AC power at the first resonant frequency provided to the initial discharge induction coil module may be performed simultaneously with or immediately before changing to the second resonant frequency. Whether the main inductively coupled plasma is generated may be determined by detecting the current Ib or detecting the AC power P2 of the second resonant frequency.

The first gas may be an ignition gas advantageous to ignite. The first gas may be argon, carbon dioxide, or nitrogen. Meanwhile, the second gas is a process gas that is difficult to ignite and may include a fluorine-containing gas or the like. Therefore, when using a gas that is difficult to ignite in the initial stage, the gas may first be discharged as a first gas that is easily ignited in the initial stage and may be changed to a second gas ( S280 ). The main inductively coupled plasma of the first gas may be changed to the main inductively coupled plasma of the second gas while maintaining approximately the same pressure. In general, the actual plasma resistance of the fluorine-containing gas may be smaller than the plasma resistance of the argon gas. Accordingly, when the gas is replaced with the second gas, the current Ib flowing through the main discharge induction coil module 103 may increase, and the AC power P3 of the second resonance frequency fb may increase.

23 is a conceptual diagram illustrating a plasma generating apparatus according to another embodiment of the present invention.

Referring to FIG. 23 , the plasma generating device 400 includes a dielectric discharge tube 140 ; a seed charge generator 205 disposed in the dielectric discharge tube 140 to generate seed charges in the dielectric discharge tube 140 ; An initial discharge induction coil 120 surrounding the dielectric cylindrical tube 140 and receiving the seed charge to generate an initial discharge, and a first resonant frequency fa connected to the initial discharge induction coil 120 1 Initial discharge induction coil module 102 comprising an impedance matching network 122 ; At least one unit antenna 132 disposed to be spaced apart from the initial discharge induction coil 120, surrounding the dielectric cylindrical tube, and receiving the initial discharge to generate a main inductively coupled plasma and connected to the unit antenna 132 a main discharge induction coil module 103 including a second impedance matching network 133 providing a second resonant frequency fb; and an RF power supply 450 for supplying power to the initial discharge induction coil module 102 and the main discharge induction coil module 103 .

The RF power source 450 includes a rectifier 151 for converting AC power into DC power; a first RF power source (450a) that receives DC power from the rectifier (151) and provides AC power to the initial discharge induction coil module (102) and operates at the first resonance frequency; and a second RF power source 450b that receives DC power from the rectifier to provide AC power to the main discharge induction coil module 103 and operates at the second resonant frequency.

The first RF power source 450a includes a first inverter 456a that receives the DC power from the rectifier 151 and converts it into a first AC power of a first resonance frequency; and a first control unit 458a for controlling the first inverter.

The second RF power source 450b includes a second inverter 456b that receives the DC power from the rectifier and converts it into AC power of a second resonant frequency; and a second control unit 458b for controlling the second inverter.

The rectifier of the first RF power and the rectifier of the second RF power may be used in common. The time during which the first RF power supply and the second RF power supply operate simultaneously is very short, so that there is no problem in the operation of the second RF power supply.

24 and 25 show an initial discharge induction coil module connected to a first RF power source according to an embodiment of the present invention.

24 and 25 , the first RF power source 450a has a positive output and a negative output, and is connected to the initial ignition induction coil 120 through the first impedance matching network 122 . The initial ignition induction coil 120 has a large inductance of 8 uH level. The first impedance matching network 122 may include at least one initial discharge capacitor. The first resonant frequency fa may be given by the inductance La of the initial discharge induction coil 120 connected in series with the equivalent capacitance C'a of the initial discharge capacitor.

26 shows an initial discharge induction coil module connected to a first RF power source according to another embodiment of the present invention.

Referring to FIG. 26 , the first RF power source 450a has a positive output and a negative output, and is connected to the initial ignition induction coil 120 through the first impedance matching network 122 . The initial ignition induction coil 120 has a large inductance of 8 uH level. The first impedance matching network 122 may include a pair of initial discharge capacitors 122a and 122b.

A pair of initial discharge capacitors 122a and 122b are respectively connected to both ends of the initial discharge induction coil. A positive output of the first RF power source is connected to a first initial discharge capacitor 122a, and a negative output of the first RF power source is connected to a second initial discharge capacitor 122b. The first resonant frequency fa may be defined by the equivalent capacitance C′a of the pair of initial discharge capacitors 122a and 122b and the inductance La of the initial discharge induction coil 120 . The capacitance Ca of the first initial discharge capacitor 122a and the second initial discharge capacitor 122b may be the same, and the equivalent capacitance C′a may be Ca/2. The first resonant frequency may be given by the equivalent capacitance C'a of the initial discharge capacitor and the inductance La of the initial discharge induction coil 120 connected in series.

27 shows an initial discharge induction coil module connected to a first RF power source according to another embodiment of the present invention.

Referring to FIG. 27 , the first RF power source 450a has a positive output and a negative output, and is connected to the initial ignition induction coil 120 through the first impedance matching network 222 . The first impedance matching network 222 includes a pair of initial discharge capacitors 222a connected in series to both ends of a transformer 222c connected to the output terminal of the first RF power source 450a and the initial discharge induction coil 120, respectively; 222b). The primary coil of the transformer 222c may be connected to an output terminal of the RF power source, and the secondary coil of the transformer 222c may be connected to both ends of an initial discharge induction coil connected in series with each other and a pair of initial discharge capacitors. The impedance of the load side may be converted depending on the turns ratio (N:1) of the transformer 222c. The capacitance Ca of the first initial discharge capacitor and the first initial discharge capacitor may be the same. The first resonant frequency may be given by the equivalent capacitance C'a of the initial discharge capacitor and the inductance La of the initial discharge induction coil 120 connected in series.

28 shows an initial discharge induction coil module connected to a first RF power source according to another embodiment of the present invention.

Referring to FIG. 28 , the first RF power source 450a has a positive output and a negative output, and is connected to the initial ignition induction coil 120 through the first impedance matching network 322 .

The first impedance matching network 322 may include: a first initial discharge capacitor 322a connected in parallel to the initial discharge induction coil 120; A first initial discharge capacitor connected in parallel to each other and a second initial discharge capacitor 322b and a third initial discharge capacitor 322c respectively connected to both ends of the initial discharge induction coil are included. The equivalent capacitance of the first to third initial discharge capacitors 322a to 322c may be C′ _a =1/2 C _a . The capacitance of the first initial discharge capacitor may be 0.5 X (1-k) X Ca. The capacitance of the second and third initial discharge capacitors may be k X Ca. Here, it may be in the range 0<k<1. C _a is the capacitance of the initial discharge capacitor described in FIG. 26. The first resonant frequency may be given by the equivalent capacitance C'a of the initial discharge capacitor and the inductance La of the initial discharge induction coil 120 connected in series.

29 shows a main discharge induction coil module connected to a second RF power source according to another embodiment of the present invention.

Referring to FIG. 29 , the main discharge induction coil module 103 includes a plurality of unit antennas 132 connected in series with each other, an auxiliary capacitor 134 connected in series between adjacent unit antennas, and a plurality of unit antennas connected in series. and a second impedance matching network 133 connected to them. The plurality of unit antennas 132 may be respectively disposed on a plurality of arrangement planes perpendicular to the central axis of the dielectric discharge tube and connected in series with each other. The auxiliary capacitors 134 may be connected in series between adjacent unit antennas. The second impedance matching network 133 may include a first main capacitor 133a and a second main capacitor 133b respectively connected to both ends of the unit antennas connected in series.

The second resonant frequency fb may be given by the sum of the inductances of the unit antennas and the equivalent capacitance of the capacitors. When the capacitance of the auxiliary capacitor 134 is C1, the capacitance of each of the first main capacitor 133a and the second main capacitor 133b may be 2C1. The inductance of each of the unit antennas may be L1.

30 is a circuit diagram illustrating a full-bridge inverter used in the first inverter or the second inverter.

The inverters 456a and 456b receive DC power from the power node VP and the ground node GND. The inverters 456a and 456b receive switching signals A, B, C, and D from the controllers 458a and 458b. The inverters 456a and 456b may convert DC power into AC power in response to the switching signals A, B, C, and D.

The first and second transistors TR1 and TR2 may be connected in series between the power node VP and the ground node GND. The first diode D1 may be connected in parallel with the first transistor TR1 , and the second diode D2 may be connected in parallel with the second transistor TR2 . The first capacitor C1 may be connected in parallel with the first transistor TR1 , and the second capacitor C2 may be connected in parallel with the second transistor TR.

The third and fourth transistors TR1 and TR2 may be connected in series between the power node VP and the ground node GND. The third diode D3 may be connected in parallel with the third transistor TR3 , and the fourth diode D4 may be connected in parallel with the fourth transistor TR4 . The third capacitor C3 may be connected in parallel with the third transistor TR3 , and the fourth capacitor C4 may be connected in parallel with the fourth transistor TR4 .

When the driving frequency of the output voltage VO is adjusted, a phase difference between the output voltage and the output current may be adjusted.

31 is a circuit diagram illustrating a half-bridge inverter according to an embodiment of the present invention.

Referring to FIG. 31 , inverters 456a and 456b receive DC power from a power node VP and a ground node GND. The inverters 456a and 456b receive switching signals A and B from the controllers 458a and 458b. The inverters 456a and 456b may convert DC power into AC power in response to the switching signals A and B.

The first and second transistors TR1 and TR2 may be connected in series between the power node VP and the ground node GND. The first diode D1 may be connected in parallel with the first transistor TR1 , and the second diode D2 may be connected in parallel with the second transistor TR2 . The first capacitor C1 may be connected in parallel with the first transistor TR1 , and the second capacitor C2 may be connected in parallel with the second transistor C2 .

The first voltage division capacitor C11 and the second voltage division capacitor C22 may be connected in series between the power node VP and the ground node GND.

When the driving frequency of the output voltage VO is adjusted, a phase difference between the output voltage and the output current may be adjusted.

32 is a conceptual diagram illustrating a seed charge generator according to another embodiment of the present invention.

Referring to FIG. 32 , the seed charge generating unit 305 includes a first electrode 314 and a second electrode 316 disposed on the dielectric discharge tube 140 to provide a seed charge; and a DC power supply 312 for applying a DC high voltage between the first electrode and the second electrode.

The DC power source 312 includes an AC-DC converter 3120 for converting commercial AC power into a DC voltage (Vin); high voltage pulse generators 3122a and 3122b receiving the DC voltage Vin and generating at least one high voltage pulse from among a positive DC high voltage pulse and a negative DC high voltage pulse; and control units 3124a and 3124b for controlling the high voltage pulse generator. The high voltage pulse generators 3122a and 3122b may include: a first high voltage pulse generator 3122a configured to receive the DC voltage and generate a first high voltage pulse; and a first high voltage pulse generator 3122b receiving the DC voltage to generate a second high voltage pulse.

The controllers 3124a and 3124b for controlling the high voltage pulse generator may include: a first controller 3124a for controlling the first high voltage pulse generator 3122a; and a second controller 3124b for controlling the second high voltage pulse generator 3122b. The first high voltage pulse may be applied to the first electrode 314 , and the second high voltage pulse may be applied to the second electrode 316 . The first electrode 314 and the second electrode 316 may be disposed on an outer wall of the dielectric discharge tube 140 to be spaced apart from each other. The first high voltage pulse and the second high voltage pulse may have different polarities.

again. 10 and 11 , the DC power supply 112 that applies the DC high voltage may generate a positive high voltage pulse and/or a negative high voltage pulse. The negative high voltage pulse and the positive high voltage pulse may be applied to the first electrode 314 and the second electrode 316 , respectively.

33 is a conceptual diagram illustrating a negative high voltage pulse generator according to an embodiment of the present invention.

Referring to FIG. 33 , the high voltage pulse generator 2122 includes a primary coil receiving the DC voltage Vin of the AC-DC converter 2120 and a secondary coil generating a negative DC high voltage pulse. transformer 2122a; an inductor (L) connected in parallel to the primary coil of the transformer (2122a); a power transistor (2122b) having a grounded end and connected in series between the primary coil of the transformer (2122a); a resistor R connected in parallel with the power transistor 2122b; a capacitor (C) connected in parallel with the power transistor; and a diode (D) disposed between the other end of the power transistor (2122b) and the parallel-connected resistor (R) and capacitor (C). A controller 2124 controls the gate of the power transistor 2122b.

One end of the secondary coil of the transformer 2122a may output a negative DC high voltage pulse, and the other end of the secondary coil of the transformer 2122a may be grounded.

34 is a conceptual diagram illustrating a negative high voltage pulse generator according to another embodiment of the present invention.

Referring to FIG. 34 , the voltage pulse generator 2122 ′ includes a primary coil receiving the DC voltage Vin of the AC-DC converter 2120 and a secondary coil generating a negative DC high voltage pulse. a transformer 2122a; an inductor (L) connected in parallel to the primary coil of the transformer (2122a); and a power transistor 2122b connected in series between the ground and the primary coil of the transformer. A controller 2124 controls the gate of the power transistor, one end of the secondary coil of the transformer 2122a outputs a negative DC high voltage pulse, and the other end of the secondary coil of the transformer 2122a is grounded. can be

35 is a conceptual diagram illustrating a negative high voltage pulse generator according to another embodiment of the present invention.

Referring to FIG. 35 , the high voltage pulse generator 4122 is a transformer including a primary coil receiving the DC voltage of the AC-DC converter 2120 and a secondary coil generating a positive DC high voltage pulse. (4122a); an inductor (L) connected in parallel to the primary coil of the transformer; a power transistor 4122b connected in series between ground and the primary coil of the transformer; One end is connected to the DC voltage (Vin) of the AC-DC converter and the resistor (R) and the capacitor (C) connected in parallel with each other; One end is connected between the power transistor (4122b) and the primary coil, the other end is a diode (D) connected to the other end of the parallel-connected resistor (R) and the capacitor (C); includes. The controller 4124 controls the gate of the power transistor 412b, one end of the secondary coil of the transformer outputs a negative DC high voltage pulse, and the other end of the secondary coil of the transformer may be grounded. have.

36 is a conceptual diagram illustrating a positive high voltage pulse generator according to another embodiment of the present invention.

Referring to FIG. 36 , the high voltage pulse generator 5122 includes a primary coil receiving the DC voltage Vin of the AC-DC converter 2120 and a secondary coil generating a positive DC high voltage pulse. a transformer 5122a; an inductor (L) connected in parallel to the primary coil of the transformer (5122a); a power transistor (5122b) connected in series between ground and the primary coil of the transformer (5122a); a resistor R connected in parallel with the power transistor 5122b; a capacitor (C) connected in parallel with the power transistor (5122b); and a diode (D) disposed between the other end of the power transistor (5122b) and the parallel-connected resistor (R) and capacitor (C). The primary coil and the secondary coil have a phase difference of 180 degrees, the controller 5124 controls the gate of the power transistor, and one end of the secondary coil of the transformer outputs a positive DC high voltage pulse, , the other end of the secondary coil of the transformer is grounded.

37 is a view for explaining a unit antenna according to another embodiment of the present invention.

Referring to FIG. 37 , the unit antenna 132 ′ includes a first antenna 132a disposed in contact with the dielectric discharge tube 140 in an arrangement plane perpendicular to the central axis of the dielectric discharge tube and forming a loop; A second antenna 132b continuously connected to the first antenna 132a and disposed to surround the first antenna 132b to form a loop may be included. The unit antenna 132' has a rectangular cross section, and the first antenna 132a is in close contact with the dielectric discharge tube to cool the dielectric discharge tube.

In the above, the present invention has been illustrated and described with respect to specific preferred embodiments, but the present invention is not limited to these embodiments, and those of ordinary skill in the art to which the present invention pertains in the claims. It includes all of the various types of embodiments that can be implemented within the scope that does not depart from the technical spirit.

102: initial discharge induction coil module
103: main discharge induction coil module
120: initial discharge induction coil
132: unit antenna

Claims (23)

dielectric discharge tube;
an initial discharge induction coil module including an initial discharge induction coil surrounding the dielectric discharge tube and generating an initial discharge, and a first impedance matching network connected to the initial discharge induction coil to provide a first resonant frequency;
a plurality of unit antennas disposed to be spaced apart from the initial discharge induction coil, surrounding the dielectric discharge tube, receiving the initial discharge to generate a main inductively coupled plasma, and a second resonance frequency connected to the unit antennas 2 main discharge induction coil module comprising an impedance matching network; and
and an RF power supply for supplying power to the initial discharge induction coil module and the main discharge induction coil module. According to claim 1,
The first impedance matching network comprises an initial discharge capacitor connected in series to the initial discharge induction coil. According to claim 1,
The first impedance matching network comprises a pair of initial discharge capacitors respectively connected to both ends of the initial discharge induction coil. According to claim 1,
The first impedance matching network includes a transformer and a pair of initial discharge capacitors respectively connected to both ends of the initial discharge induction coil,
The primary coil of the transformer is connected to the output terminal of the RF power source,
The secondary coil of the transformer is connected to both ends of an initial discharge induction coil connected in series with each other and a pair of initial discharge capacitors. According to claim 1,
The first impedance matching network comprises:
a first initial discharge capacitor connected in parallel to the initial discharge induction coil;
A plasma generating apparatus comprising: a first initial discharge capacitor connected in parallel with each other; and a second initial discharge capacitor and a third initial discharge capacitor connected to both ends of the initial discharge induction coil, respectively. According to claim 1,
In the main discharge induction coil module,
The plurality of unit antennas are respectively disposed on a plurality of arrangement planes perpendicular to the central axis of the dielectric discharge tube and are connected in series with each other,
Auxiliary capacitors are connected in series between adjacent unit antennas,
The second impedance matching network comprises a first main capacitor and a second main capacitor respectively connected to both ends of the unit antennas connected in series. According to claim 1,
The RF power source is:
a rectifier that converts commercial AC power into DC power;
an inverter that receives the DC power and converts it into RF power in response to switching signals of a controller; and
A control unit for controlling a driving frequency and power by controlling the switching signals,
The RF power source operates at the first resonant frequency during initial discharge, and operates at the second resonant frequency when the main inductively coupled plasma is generated. According to claim 1,
The RF power source is:
a first RF power supply providing AC power to the initial discharge induction coil module and operating at the first resonant frequency; and
and a second RF power supply that provides AC power to the main discharge induction coil module and operates at the second resonant frequency.
The first RF power source includes:
a first rectifier for converting AC power into DC power;
a first inverter receiving the DC power of the first rectifier and providing AC power of a first resonance frequency to the initial discharge induction coil module; and
A first control unit for controlling the output of the first inverter,
The second RF power source includes:
a second rectifier for converting AC power into DC power;
a second inverter receiving the DC power of the second rectifier and providing AC power of a second resonance frequency to the main discharge induction coil module; and
and a second control unit controlling an output of the second inverter. According to claim 1,
The RF power source is:
a rectifier that converts AC power to DC power;
a first RF power supply receiving the DC power of the rectifier to provide AC power to the initial discharge induction coil module and operating at the first resonance frequency; and
and a second RF power source that receives the DC power from the rectifier to provide AC power to the main discharge induction coil module and operates at the second resonant frequency. 10. The method of claim 9,
The first RF power source includes: a first inverter that receives the DC power of the rectifier and converts it into a first AC power of a first resonance frequency; and
a first control unit for controlling the first inverter;
The second RF power source is a second inverter that receives the DC power of the rectifier and converts it into AC power having a second resonance frequency; and
and a second control unit for controlling the second inverter. 10. The method of claim 9,
The first RF power source operates in a frequency range of 4 MHz to 5 MHz,
The second RF power source plasma generating device, characterized in that it operates in a frequency range of 400 kHz to 4 MHz. 11. The method of claim 10,
Each of the first inverter and the second inverter has a full-bridge structure or a half-bridge structure. According to claim 1,
Further comprising a first detection sensor for detecting the current flowing in the initial discharge induction coil,
The RF power source detects a transition from the capacitive coupling mode to the inductive coupling mode using the output of the first detection sensor to change the driving frequency from the first resonant frequency to the second resonant frequency. . According to claim 1,
Further comprising a second detection sensor for detecting the current flowing in the main discharge induction coil module,
The RF power source detects that the main inductively coupled plasma is formed by using the output of the second detection sensor to cut off the power provided to the initial discharge induction coil module. According to claim 1,
The initial discharge induction coil is in the form of a solenoid, plasma generating device, characterized in that wound in multiple layers. According to claim 1,
The initial discharge induction coil is a plasma generating device, characterized in that the three-layer structure of an internal solenoid coil, an intermediate solenoid coil, and an external solenoid coil. According to claim 1,
The unit antenna is:
a first antenna disposed in contact with the dielectric discharge tube in an arrangement plane perpendicular to the central axis and forming a loop;
a second antenna disposed to surround the first antenna and forming a loop; and
and a third antenna disposed to surround the second antenna and forming a loop. According to claim 1,
The unit antenna includes a plurality of windings disposed on the same arrangement plane, and the plasma generating apparatus further comprises a "ㅛ"-shaped insulating spacer to insulate the plurality of windings. According to claim 1,
The unit antenna is:
a first antenna disposed in contact with the dielectric discharge tube in an arrangement plane perpendicular to the central axis and forming a loop; and
a second antenna disposed to surround the first antenna and forming a loop; Plasma generator comprising a. injecting a first gas into the dielectric discharge tube;
performing an initial discharge of the first gas with AC power of a first resonant frequency using an initial discharge induction coil and a first impedance matching network connected to the initial discharge induction coil; and
generating a main inductively coupled plasma of the first gas with AC power having a second resonant frequency different from the first resonant frequency using a plurality of unit antennas and a second impedance matching network; How the generator works. 21. The method of claim 20,
and maintaining the main inductively coupled plasma while changing the first gas to the second gas. 21. The method of claim 20,
After the initial discharge of the first gas, generating a preliminary main inductively coupled plasma of the first gas from the initial discharge with AC power near a second resonant frequency using a plurality of unit antennas and a second impedance matching network. The method of operating a plasma generating device, characterized in that it further comprises. 23. The method of claim 22,
When the preliminary main inductively coupled plasma is generated, the method of operating a plasma generating device further comprising the step of blocking the AC power of the first resonant frequency.

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