TWI618570B - Low pressure plasma reactor for exhaust gas treatment - Google Patents

Abstract

The invention relates to a low-pressure plasma reactor which can be used for treating the exhaust gas when the exhaust gas in the process chamber contains a fluorine-based or chlorine-based gas, which minimizes the etching of the internal surface of the dielectric body due to ion collision and The exhaust gas treatment is continuously performed, and the magnetic field generator and the casing are included so that the reactor has a dual-chamber structure and can be safely processed. To this end, an optimized magnetic field value that reduces the etching of the dielectric surface caused by plasma ions is provided and applied. The casing not only physically seals the dielectric tube and the driving electrode that covers its outer surface with a ring shape, and The magnetic field generator can block the electromagnetic of the low-pressure plasma reactor.

Description

LOW PRESSURE PLASMA REACTOR FOR EXHAUST GAS TREATMENT

The present invention relates to a plasma reactor, and more specifically, to an electricity for decomposing exhaust gas containing unreacted process gas (gas), purge gas, or a part of initial reactants discharged in a low-pressure process. A plasma reactor, in particular, relates to a low-pressure plasma reactor that can solve the problem of erosion of the inner surface of the reactor when the situation of exhaust gas (including fluorine-based or chlorine-based gas) becomes serious.

In the processes of semiconductors, display devices, solar cells, etc., processes such as functional thin film formation and dry etching are applied. This process is usually implemented in a vacuum chamber. In functional film formation, a variety of metal and non-metal precursors are used as the process gas. In dry etching, various etchings are also used. gas.

A system for exhausting a process chamber is a system in which various constituent elements including a process chamber, a vacuum pump, a scrubber, and the like are connected to each other through an exhaust line. At this time, the exhaust gas discharged from the self-made process chamber varies according to the manufacturing process, but may include unreacted precursors in a gas molecule or an aerosol state. (precursor), solid crystal (seed crystal), etc., may further include an inert gas as a carrier gas. This exhaust gas flows into the vacuum pump along the exhaust line. Inside the vacuum pump, the exhaust gas is compressed at a high temperature of 100 ° C or higher. Therefore, the phase variation of the constituent elements of the exhaust gas is induced, and it is easy to form a stacked solid inside the vacuum pump. By-products can cause the vacuum pump to malfunction, resulting in unexpected interruptions in the process.

As a previous method to improve the failure of the vacuum pump due to exhaust gas, purging gas is injected into the vacuum pump in the exhaust gas to reduce the partial pressure of components that can form solid by-products in the exhaust gas. And to minimize the formation of by-products. The most commonly used scrubbing gases are dry-air or nitrogen.

The toxicity and flammability of these exhaust gases are relatively serious. When released to the atmosphere, they are more harmful to the environment. Therefore, it is necessary to convert the harmless substances before discharge. So far, in most cases, they are located behind the vacuum pump. The scrubber at the end plays the role of the conversion process. The pressure from the rear end of the vacuum pump is close to atmospheric pressure, so the scrubber used is a common Burn-wet, Heat-wet type, or a dry or wet process using a catalyst. It has decomposition efficiency and generates a large amount of nitrogen compounds. (NO _x ), requiring frequent and cumbersome management and other issues. Recently, a plasma scrubber technology using an atmospheric piezoelectric plasma at the back end of the same vacuum pump was introduced, which has limitations in practical use due to high power consumption and difficulty in improving processing efficiency.

A more effective method to solve the problem of solid particles and the like accumulated inside the vacuum pump due to the exhaust gas is to install a hot trap or a cold trap on the exhaust line. However, this method has limitations due to higher energy consumption and lower processing efficiency. Recently, in order to comprehensively improve the exhaust line, The problem of using a conventional atmospheric pressure scrubber at the back of a vacuum pump or a vacuum pump, try to add a low-pressure plasma device to the front of the vacuum pump, and restructure it in the form of main equipment-low-pressure plasma device-vacuum pump-scrubber. The overall exhaust system achieves good results. The low-voltage plasma device of this purpose has a structure different from the existing atmospheric piezoelectric plasma device in order to realize easy driving and maximization of performance at a low voltage.

Korean Registered Patent No. 1065013 discloses a plasma reactor technology that decomposes exhaust gas by a method of causing a dielectric barrier discharge by applying an AC (Alternating Current) driving voltage. However, the above-mentioned prior art has the following problems, and there are limitations in the application in the actual process that requires continuous operation for 24 hours and 365 days: during the occurrence of the dielectric barrier discharge, the ions in the plasma continue to be nearly vertical The incident touches the surface of the dielectric body, and sputtering or erosion of the surface of the dielectric body occurs, thereby changing the discharge environment conditions due to the deformation of the dielectric substance, and shortening the part replacement cycle. Furthermore, when the exhaust gas contains a fluorine-based or chlorine-based gas, the surface erosion of the dielectric body and its influence become serious. Therefore, there is a need to develop a technology for preventing decomposition of the surface of a dielectric in a plasma decomposition device that decomposes a fluorine-based or chlorine-based exhaust gas.

The problem to be solved by the present invention is to provide not only effective decomposition of exhaust gas containing fluorine-based and / or chlorine-based gases, but also effective prevention of erosion inside the plasma reactor caused by ions of the above-mentioned gases, thereby being practically usable Low-pressure plasma reactor for exhaust gas decomposition in an operating environment that requires continuous operation for 24 hours and 365 days.

The inventors and others have completed the present invention through long-term research and found that if the direction of the ions' motion is not to be directed toward the interior of the plasma reactor, a magnetic field is used to apply a Lorentz force to the ions, but only When the size is a fixed value or more depending on the type of ions, erosion can be effectively suppressed.

The invention provides a low-pressure plasma reactor for waste gas treatment, which is a low-pressure plasma reactor that decomposes exhaust gas discharged from a self-made process chamber. The above-mentioned low-pressure plasma reactor includes a dielectric tube. A pair of ground electrodes located at both ends of the dielectric tube in an extended form of the dielectric tube; a driving electrode formed to be separated from the pair of ground electrodes and covering the length of the dielectric tube The ring shape of the outer surface is connected to the AC power supply unit; the magnetic field generating unit is configured to form a magnetic field in the longitudinal direction of the dielectric tube, and is configured to be insulated and covered outside the driving electrode; and a housing It is in the form of preventing the exhaust gas from flowing to the outside when the crack of the dielectric tube is generated. In order to block the electromagnetic wave from being radiated to the outside, the outside of the driving electrode and the outside of the magnetic field generating portion are sealed and covered; The intensity of the magnetic field formed by the magnetic field generating section along the length of the dielectric tube is limited to the formula (m _i : plasma ion mass, e: charge amount, τ: mean collision time).

In addition, the present invention provides a low-pressure plasma reactor for exhaust gas treatment, wherein the low-pressure plasma reactor further includes a conductive elastic buffer portion for realizing the driving electrode and the dielectric tube. The buffer and seal are interposed between the driving electrode and the dielectric tube.

In addition, the present invention provides a low-pressure plasma reactor for exhaust gas treatment, wherein the conductive elastic buffering portion is a graphite sheet, a conductive polymer material sheet, or a metal foam.

In addition, the present invention provides a low-pressure plasma reactor for exhaust gas treatment, wherein the magnetic field generating section is a solenoid coil, and the strength of the magnetic field is adjusted by a power source connected to the coil.

In addition, the present invention provides a low-pressure plasma reactor for exhaust gas treatment, wherein the magnetic field generating section is a helmholtz coil, and the strength of the magnetic field is adjusted by a power source connected to the coil.

Further, the present invention provides a low pressure plasma reactor for exhaust gas treatment, wherein m _i is fluoride (F ^-) or chloride ions (Cl ^-) of the mass, The value is 0.01 T.

The present invention also provides a low-pressure plasma reactor for exhaust gas treatment, wherein the magnetic field generating portion is a cylindrical permanent magnet.

In addition, the present invention provides a low-pressure plasma reactor for exhaust gas treatment, wherein a portion of the ground electrode that is in contact with the dielectric tube has a flange structure, and the casing is configured to communicate with the dielectric tube. The cylindrical shape arranged in a concentric manner has its two end surfaces in contact with the flange surfaces, respectively, and forms a double chamber with the dielectric tube.

In addition, the present invention provides a low-pressure plasma reactor for exhaust gas treatment, wherein the dual chamber includes a cooling device using air, nitrogen, or a coolant as a cooling medium.

In addition, the present invention provides a low-pressure plasma reactor for exhaust gas treatment, wherein the cooling device is located in the dual chamber and includes a temperature sensor, a pressure sensor, or a gas sensor. The sensor uses the measured value of the sensor to feedback control the degree of cooling.

In addition, the present invention provides a low-pressure plasma reactor for exhaust gas treatment, wherein the above-mentioned low-pressure plasma reactor is disposed between a process chamber and a vacuum pump, or constitutes The booster pump and the backing pump of the vacuum pump.

In addition, the present invention includes a low-pressure plasma reactor for exhaust gas treatment, wherein the housing further includes a sensor portion, and the sensor portion can sense exhaust gas leaked from the dielectric tube.

In addition, the present invention provides a low-pressure plasma reactor for waste gas treatment, which is a low-pressure plasma reactor that decomposes exhaust gas discharged from a self-made process chamber. The low-pressure plasma reactor includes a booster pump, The exhaust gas is exhausted from the exhaust port of the process chamber; a first end portion of the tube-shaped first ground electrode is connected to the exhaust port of the booster pump for the exhaust gas to pass through; the dielectric tube has an end portion A flange is combined with the other end portion of the first tubular ground electrode to allow the exhaust gas to pass through; a second shape of the tubular ground electrode is connected to the other end of the dielectric tube through the flange. The end portion is combined to allow the exhaust gas to pass through; a support pump to exhaust the exhaust gas from the other end portion of the second ground electrode; and a drive electrode formed to be separated from the first ground electrode and the second ground electrode and covering the above. The ring shape of the outer surface of the dielectric tube in the longitudinal direction is connected to the AC power supply unit; the magnetic field generating unit is configured to form a magnetic field in the longitudinal direction of the dielectric tube, and is configured to maintain insulation and cover the outside of the driving electrode; And shell It has a cylindrical shape arranged concentrically with the above-mentioned dielectric tube so as to seal and cover the outside of the driving electrode and the outside of the magnetic field generating portion, and both ends of the case are respectively connected to the flange surface; and the case The body and the dielectric tube form a dual chamber. The dual chamber includes a cooling device using air, nitrogen, or a coolant as a cooling medium. The cooling device is in the dual chamber. The cooling device includes a temperature sensor. , Pressure sensor, or gas sensor.

The plasma reactor of the present invention has the following effects.

1. The plasma reactor of the present invention can decompose the evaporation precursor, a part of the initial reactants, and / or the etching gas discharged from the self-made process chamber and flow it into the vacuum pump, so that the solid phase particles can be suppressed inside the vacuum pump. Or the formation and growth of membranes to prevent unexpected failures of the vacuum pump, which can prevent the interruption of vacuum process advancement and wafer scrap caused by this. In addition, since it has a vacuum area that is used in parallel with the front end of the vacuum pump, it can significantly reduce power consumption compared to an atmospheric piezoelectric slurry device.

2. In the plasma reactor of the present invention, the electrodes used to form the plasma are not located in the inner region of the dielectric tube through which the exhaust gas passes, so that the corrosion of the electrode caused by the exhaust gas and the reduction of the exhaust capacity caused by the electrode can be eliminated.

3. The plasma reactor of the present invention uses an AC power source with a frequency lower than RF (Radio Frequency, radio frequency), so it can span a wide pressure range, and easily realize the generation and maintenance of plasma, so that it can be used without electricity. A separate carrier gas or a pressure adjustment device formed by the plasma easily forms a plasma on the exhaust line, and the plasma state can be maintained even if there is a sudden pressure change caused by a continuous process step.

4. The plasma reactor of the present invention includes a magnetic field generating section, and can effectively prevent sputtering or etching of the dielectric body by reducing the angle of ions incident on the surface of the dielectric body exposed to the plasma in a nearly vertical manner. Therefore, the serious erosion of the surface of the dielectric body by the exhaust gas containing fluorine-based or chlorine-based gas in the decomposition environment can be suppressed, and thus the actual use in the use environment that requires continuous operation can be achieved.

5. The coil-type magnetic field generating unit applied to the plasma reactor of the present invention can easily adjust the intensity of the magnetic field by adjusting the amount of current flowing into the coil, and therefore can efficiently form a magnetic field according to the etching environment generated by the incident ions. The magnitude of the magnetic field that actually obtains the effect of etching improvement is to deal with the problem of erosion inside the plasma reactor.

6. The plasma reactor of the present invention is provided with a substantially double-chamber-shaped casing covering the outside of the magnetic field generating portion to protect the internal structure, and can prevent process gas when a crack of the dielectric tube is generated. Flowing to the outside, blocking the radiation of electromagnetic waves to the outside.

11‧‧‧Process Chamber

12‧‧‧Vacuum pump

12a‧‧‧ booster pump

12b‧‧‧Support pump

13‧‧‧Air scrubber

14‧‧‧ process chamber exhaust line

15‧‧‧Vacuum pump exhaust line

50‧‧‧plasma reactor

51‧‧‧ ground electrode

51a‧‧‧ flange

52‧‧‧ Dielectric

53, 53b‧‧‧Drive electrode

53a‧‧‧Elastic buffer section

53a1‧‧‧Elastic cushioning part 1

53a2‧‧‧Elastic cushioning part 2

53b1‧‧‧first drive electrode

53b2‧‧‧Second driving electrode

54‧‧‧ Magnetic field generator

54a‧‧‧solenoid coil

54b1, 54b2, 54b3‧‧‧ Helmholtz coil

54c‧‧‧permanent magnet

55‧‧‧shell

56‧‧‧ Valve

58‧‧‧Sensor Section

66‧‧‧ collision

77‧‧‧Exhaust gas

88‧‧‧ exhaust

100‧‧‧ surface

200‧‧‧ ion

FIG. 1 schematically shows a state where a low-pressure plasma reactor for exhaust gas treatment according to an embodiment of the present invention is connected between a process chamber and a vacuum pump.

FIG. 2 schematically shows a state where a low-pressure plasma reactor for exhaust gas treatment according to an embodiment of the present invention is connected between a booster pump and a backing pump constituting a vacuum pump.

3a and 3b are schematic views showing a ground electrode, a driving electrode, and a magnetic field generating section in a low-pressure plasma reactor for exhaust gas treatment according to the present invention.

Figures 4a and 4b are diagrams illustrating the electric field and plasma generated in a plasma reactor when a power source is applied to the ground electrode and driving electrode structures shown in Figures 3a and 3b.

FIG 5 is a fluorine ion (F ^-) in a near vertical manner when incident on the surface of the oxide-based Al-Y, Al ₂ O ₃ and Y ₂ O ₃ and constituting ratio and applied to the fluoride ions (F ^-) of The surface etching rate corresponding to the acceleration voltage (the magnitude of the electric field).

FIG. 6 is a diagram for explaining a structure of a dielectric tube, a ground electrode, a driving electrode, an elastic buffer portion, a magnetic field generating portion, and a case in the plasma reactor of the present invention.

FIG. 7 illustrates a case structure including a cooling device and a sensor according to an embodiment of the present invention.

FIG. 8 shows an embodiment of the present invention using a solenoid coil as a magnetic field generator. The combined state and decomposition state of the plasma reactor.

FIG. 9 shows a coupled state and a disassembled state of a plasma reactor using a Helmholtz coil as a magnetic field generator according to an embodiment of the present invention.

FIG. 10 shows a coupled state and a disassembled state of a plasma reactor using a cylindrical permanent magnet as a magnetic field generating unit according to an embodiment of the present invention.

11a and 11b are diagrams for explaining a change in a motion trajectory of a charged particle accelerated by an electric field in a plasma reactor due to a magnetic field generated by a magnetic field generating section.

Fig. 12a and Fig. 12b show potential and particle density distributions in a region adjacent to the inner surface of the dielectric tube in the plasma reactor.

13a and 13b show a single electric charge due to the kinetic energy (E _K ) incident on the surface of the dielectric body and the angle of incidence (θ) in a magnetic field in the direction α with respect to the dielectric tube axis. The degree of etching of the dielectric surface caused by the sputtering of particles and charged particle flux.

FIG. 14 shows changes in the etching rate of the surface of the dielectric body corresponding to the strength of the magnetic field when no magnetic field is applied when a magnetic field parallel to the dielectric tube axis is applied.

With reference to the drawings, various embodiments are disclosed. In the following description, in order to facilitate the understanding of the entire text, a plurality of specific details are disclosed in one or more embodiments. However, it should be understood that the embodiments can be carried out even if the specific detailed matters do not exist. The following description and accompanying drawings are specific illustrations describing one or more embodiments in detail. However, the illustrated examples are schematic, and some of the various methods may be utilized according to the principles of the multiple embodiments, and the description described is intended to be all inclusive. Contains such examples and equivalents.

Various embodiments and features are proposed by a device that can include multiple parts and components. In addition, it should be understood and understood that a plurality of devices may include additional parts and components, and / or may not all include the parts and components mentioned in connection with the drawings.

The "embodiments", "examples", "exemplifications" and the like used in this specification should not be interpreted as any embodiment or design described being superior to other embodiments or designs or having advantages. The terms "chamber", "electrode", "housing", "pump" and the like used below generally refer to vacuum-related entities.

Also, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or". That is, when it is not differently specified or the context is ambiguous, "X uses A or B" means one of natural inclusive substitution. That is, in a case where X uses A, X uses B, or X uses all of A and B, "X uses A or B" can be applied to each of the cases. The term "and / or" used in this specification should be understood to mean and include as many combinations as possible of one or more of the listed related items.

The term "including" and / or "including" means that there are corresponding features, steps, actions, constituent elements, and / or constituent parts, but it should be understood that the presence or addition of one or more other features, Steps, actions, components, components, and / or combinations thereof. It should be construed that in the present specification and the scope of the application, the singular number generally means "one or more" when it is not specifically specified differently or when the context is unclear because it is expressed in the singular form.

The plasma reactor 50 of the present invention is disposed between a process chamber 11 and a vacuum pump 12 that realize film formation or dry etching in a vacuum environment, and is used for a low-pressure ring. Exhaust gas 77 containing unreacted gas, purge gas, or initial reactant is decomposed in the environment. The plasma reactor includes: a dielectric tube 52 through which the exhaust gas 77 containing the unreacted gas passes; a ground electrode 51 and a driving electrode 53 The magnetic field generating unit 54 covers the outside of the dielectric tube to generate a magnetic field substantially parallel to the longitudinal direction of the dielectric tube, and alleviates the cause. Erosion of the inner surface of the dielectric tube caused by ion sputtering; and a cylindrical case 55 that covers the outside of the magnetic field generating portion and is arranged concentrically with the dielectric tube.

Plasma refers to a state in which molecules, atoms, electrons, and ions coexist. Charged particles such as electrons or ions move by the electric and magnetic fields formed in space. On the surface 100 exposed to the plasma, a collision of ions 200 occurs on the surface 100 by the plasma potential, and erosion due to the collision of the accelerated ions 200 occurs.

Such erosion is caused by physical sputtering or a chemical reaction, and when collision of ions that can chemically react with the surface is caused, reactive ion etching can be caused and accelerated. In the present specification, the term "erosion" is used to include all inclusive meanings including sputtering due to ion collision, corrosion due to chemical reaction, and etching accelerated by collision of reactive ions.

In a deposition process or a cleaning process of a semiconductor, a display device, or a solar cell process, a fluorine (F) -based or chlorine (Cl) -based gas is used. As a specific example, in a process of atomic layer vapor deposition oxide (ALD-Oxide) or atomic layer vapor deposition nitride (ALD-Nitride), a liquid precursor of HexaChlorodisiline (Si ₂ Cl ₆ ) ( precursor), in the dry etching process, using an etching gas such as CF ₄ , CHF ₃ , SF _6, etc., or in the cleaning process, using a large amount of fluorine-based or chlorine-based gases such as NF ₃ , ClF ₃ . After the precursor gases and flows into the plasma in the decomposition reactor, contains a large amount of the activated form of the fluoride ions (F ^{-) -} plasma and radical (Radical), chloride (Cl). Ions are accelerated by the potential difference applied to the electrode, and they collide with the surface of the dielectric to cause surface etching. At this time, physical sputtering is caused on the surface of the dielectric, or fluorine or chlorine compounds are generated on the surface of the dielectric. Volatilization, and cause erosion of the material, greatly reducing the life of the plasma reactor.

One of the methods to prevent dielectric erosion as described above is to use a dielectric material having excellent etching resistance. For example, it uses a powder of alumina (Alumina, Al ₂ O ₃ ) and yttrium oxide (Yttria, Y ₂ O ₃ ) for sintering, or has excellent sputtering resistance for alumina material spray coating. The method of yttrium oxide, etc., even if this method uses expensive materials, it cannot fundamentally solve the problem of erosion caused by plasma.

The present invention is intended to control the motion trajectory of the ions 200 colliding with the surface 100 exposed to the plasma to solve the problem of erosion of the material, rather than trying on the material.

The process chamber 11 used for the film forming or etching process of the prior art is connected to the vacuum pump 12 through the process chamber exhaust line 14 and the vacuum pump 12 and the scrubber 13 are connected through the vacuum pump exhaust line 15 . The exhaust gas containing the precursor for thin film evaporation can form crystal nuclei and be granulated under specific temperature and pressure conditions. The particles generated in the process chamber grow during the exhaust process and flow into the vacuum pump or scrubber. Or when the vacuum pump or the scrubber is granulated and accumulated, the vacuum pump or the scrubber is gradually damaged.

FIG. 1 schematically shows a state where a low-pressure plasma reactor 50 for exhaust gas treatment according to an embodiment of the present invention is connected between a process chamber 11 and a vacuum pump 12. In an embodiment of the present invention, the process chamber 11 and the vacuum pump 12 are connected by a process chamber exhaust line 14, and the vacuum pump 12 and the scrubber 13 are discharged by a vacuum pump. The gas line 15 is connected, and a low-pressure plasma reactor 50 is provided in the middle of the exhaust line 14 of the process chamber. In one embodiment of the present invention, the vacuum pump 12 includes a booster pump 12a and a backing pump 12b. The plasma reactor 50 performs the following functions: It decomposes the exhaust gas containing the evaporation precursor or a part of the initial reactant or the reactive etching gas moved by the self-made process chamber to prevent particles from flowing into the vacuum pump 12 or inside the vacuum pump. A metal film is formed to protect the vacuum pump. In addition, due to the large toxicity and flammability contained in the exhaust gas, the plasma reactor 50 is primarily decomposed before the scrubber, and if released to the atmosphere, particles that are harmful to the environment, metallic non-metallic precursors, or reactivity After the etching gas is transmitted to the scrubber, the total decomposition efficiency of the harmful substances is greatly improved.

FIG. 2 schematically shows a state where a low-pressure plasma reactor 50 for exhaust gas treatment according to an embodiment of the present invention is connected between a booster pump 12a and a backing pump 12b. In the plasma reactor 50 according to an embodiment of the present invention, since the booster pump 12a forms a strong exhaust gas flow, the possibility of lighter decomposed particles generated in the plasma reactor to flow back to the process chamber can be completely eliminated. . The reason is that if the ions generated in the plasma reactor reach the process chamber countercurrently, the process conditions can be changed and affected.

3a and 3b are schematic diagrams showing a ground electrode 51, a drive electrode 53, and a magnetic field generator 54 of a low-pressure plasma reactor 50 for exhaust gas treatment according to the present invention. Referring to FIG. 3a, the exhaust gas 77 discharged from the self-made process chamber flows into the exhaust gas inlet of the plasma reactor. In an embodiment of the present invention, portions of the exhaust gas input port formed at both ends of the plasma reactor are made of metal bodies, and function as a ground electrode 51 forming a plasma. The ground electrode is formed in a tube shape, and the dielectric tube is connected to each other in a sealed form. In an embodiment of the present invention, the tubular ground electrode 51 and the aforementioned The dielectric tubes 52 are coupled to each other by a flange 51a. In an embodiment of the present invention, the driving electrode 53b is separated from the ground electrode 51 at a predetermined interval, and the outer surface of the dielectric tube 52 is covered in a ring shape by an elastic buffer portion 53a. In one embodiment of the present invention, the magnetic field generating unit 54 is formed in a form that is insulated and covered outside the driving electrode. The dielectric tube 52, the drive electrode 53b, and the magnetic field generator 54 have a form covered with a case 55 outside. In such an electrode arrangement, the driving electrode 53 is separated from the area where the exhaust gas passes, so the problem of electrode corrosion caused by the exhaust gas and the problem of lowered exhaust capacity caused by the electrodes can be completely eliminated. Fig. 3b shows two single driving electrodes of another embodiment of the present invention, namely the first driving electrode 53b1 and the second driving electrode 53b2, respectively. The shape of the outer surface of the dielectric tube 52.

4a and 4b are diagrams for explaining an electric field and a plasma formed in a plasma reactor when a power is applied to the ground electrode and the driving electrode structure shown in Figs. 3a and 3b. Referring to FIG. 4a, an exhaust gas 77 is input and an exhaust gas 88 (exhaust gas having a fixed pressure inside the dielectric tube) is inputted. When an AC voltage is applied to the driving electrode 53b, electron movement starts between the driving electrode 53b and the ground electrode 51. Decomposes exhaust gas and generates plasma. At this time, the ions are accelerated in the plasma region, and an ion collision 66 is caused to continue on the surface of the dielectric tube in a nearly vertical manner. Referring to FIG. 4b, in a plasma reactor in which driving electrodes in a separated form are formed, a plasma is generated between the driving electrode and the ground electrode 51 and between the first driving electrode 53b1 and the second driving electrode 53b2. In this case, the ions also impinge on the surface of the dielectric tube 66 in a near-vertical manner, and erosion occurs on the surface of the dielectric tube. As shown in the figure, the driving electrode is provided in a form that covers the outer surface of the dielectric tube. Under the condition that an AC voltage of several hundreds of kilohertz (kHz) is applied to generate a plasma, the driving electrode is Severe erosion caused by internal surfaces weight. The reason is that if a voltage is applied between the driving electrode and the ground electrode, an electric field is formed in a direction close to the inner surface of the dielectric tube in a region where the driving electrode is provided, so that the ions inside the plasma are accelerated and along the approach The vertical direction continuously hits the inner surface of the dielectric tube.

The impact of the plasma ions as described above etches the surface of the dielectric tube. FIG 5 is a fluorine ion (F ^-) in a near vertical manner when incident on the surface of the oxide-based Al-Y, Al ₂ O ₃ and Y ₂ O ₃ and constituting ratio and applied to the fluoride ions (F ^-) of The surface etching rate corresponding to the acceleration voltage (the magnitude of the electric field). In the case of sintering a dielectric tube made of expensive materials such as a mixed powder of aluminum oxide (Alumina, Al ₂ O ₃ ) and yttrium oxide (Yttria, Y ₂ O ₃ ), it cannot be used to prevent plasma ion etching. Appropriate method (Lee Seong Min, Korean ceramic technician).

FIG. 6 is a structural diagram for explaining a dielectric tube 52, a ground electrode 51, a driving electrode 53b, an elastic buffer portion 53a, a magnetic field generating portion 54, and a case 55 in a plasma reactor 50 of the present invention. In order to effectively solve the problem of erosion on the inner surface of a plasma reactor having a structure in which a driving electrode is provided in a form of covering the outer surface of a dielectric tube, a device for forming a magnetic field in a plasma region is added in the present invention. In one embodiment of the present invention, the driving electrode 53b is surrounded by the dielectric tube 52 with the elastic buffering portion 53a interposed therebetween. As described above, the elastic buffering portion is selected to have a conductive elastic buffering portion so that not only the mechanical buffering and close contact function can be performed, but also the conductive function can be simultaneously performed. In one embodiment of the present invention, the elastic buffer portion is a graphite sheet, a conductive polymer material sheet, or a metal foam.

The device for forming a magnetic field may be disposed outside the dielectric tube. In an embodiment of the present invention, the magnetic field generating portion may be formed by a solenoid coil, a Helmholtz coil, or a permanent magnet connected to a power source. If a magnetic field is introduced into the plasma area, the charged particles Since the particle is subject to a Lorentz force, the trajectory of the charged particles inside the plasma changes. If the amount of current flowing into the coil is adjusted, the magnetic field strength can be adjusted, and the incident angle of the incident ions can be adjusted according to the magnetic field strength.

However, if the magnetic field intensity does not reach a fixed value, the surface etching rate of the ions does not change as described below, or the etching rate becomes higher instead. Therefore, in accordance with the etching environment formed by the incident ions, a magnetic field strength that can substantially obtain an etching improvement effect is efficiently formed, and thus the problem of erosion inside the plasma reactor can be addressed.

In addition, the plasma reactor of the present invention is structured to include a practically double-chambered case 55 that covers the outside of the magnetic field generating portion, thereby protecting the internal structure and causing a crack in the dielectric tube. At this time, the process gas can be prevented from flowing to the outside, and electromagnetic waves can be blocked from being radiated to the outside. The portion of the ground electrode that is in contact with the dielectric tube has a flange structure, and the casing has a cylindrical shape arranged concentrically with the dielectric tube, and both end surfaces thereof are in contact with the flange surface, respectively, and The above-mentioned dielectric tubes together constitute a double chamber. The dual chamber also has the following functions: a physical seal that responds to the leakage of exhaust gas from the plasma-generating space, that is, a dielectric tube; a block, which prevents the electrodes that can be generated at the drive electrode and / or the magnetic field generating section Electromagnetic waves are emitted to the outside.

FIG. 7 illustrates a case structure including a cooling device and a sensor according to an embodiment of the present invention. The dual-chamber space constituted by the above-mentioned housing may be configured with a cooling unit using a cooling medium such as air, nitrogen, or a coolant, and a valve 56 for regulating the cooling medium, and a sensor unit 58, and may be configured as required. Cooling is simply performed in a control mode, or in a feedback control mode that is linked according to the sensor value. In an embodiment of the present invention, the cooling device includes a temperature sensor and / or a pressure sensor in the dual chamber, and uses a measurement value feedback of the sensor to control the degree of cooling. In another embodiment of the present invention, the casing includes a perceptible self-dielectric leak. Sensor section for leaking exhaust gas.

FIG. 8 shows a coupled state and a disassembled state of a plasma reactor using a solenoid coil 54 a as a magnetic field generating unit according to an embodiment of the present invention. 8, the plasma reactor 50 includes a ground electrode, a dielectric tube 52, a driving electrode 53, a solenoid coil 54 a, and a case 55. In one embodiment of the present invention, the ground electrodes 51 may be formed on both sides of the dielectric tube 52 in the length direction. The above-mentioned ground electrode 51 may be composed of a metal exhaust pipe itself. In an embodiment of the present invention, a dielectric tube having a driving electrode formed on an outer surface thereof, and a cylindrical case 55 covering the dielectric tube externally are coaxial with the ground electrode 51 and are fastened in a coaxial manner. The double chamber is formed to protect the structure such as the solenoid coil. When the crack of the dielectric tube is generated, the process gas is prevented from flowing to the outside, and it can be blocked by being grounded. The electromagnetic wave generated by the solenoid coil is radiated to the outside. In another embodiment of the present invention, the ground electrode and the case may be separated, and the case may also be made of a non-conductor. The dielectric tube 52 may be formed of a dielectric substance so that it can function as a dielectric according to a voltage applied to the driving electrode 53. In one embodiment of the present invention, the dielectric tube 52 may be made of alumina, zirconia (ZrO ₂ ), yttrium oxide (Y ₂ O ₃ ), sapphire, quartz tube, glass tube, or the like. The driving electrode 53 is formed in a ring shape covering the outer surface of the dielectric tube 52, and is configured to maintain a specific distance from the ground electrode 51. When the driving electrode 53 is located inside the dielectric body, it eliminates corrosion and exhaustion caused by exhaust gas. The problem of decreased gas efficiency. In one embodiment of the present invention, the driving electrode may be configured as a single body. In another embodiment of the present invention, the driving electrodes may be configured in a form provided to be spaced apart from each other, or a plurality of forms in which voltages are applied at different periods. An alternating current whose voltage varies according to a fixed period can be passed through the driving electrode 53. The frequency of the alternating current can be an AC current ranging from several hundreds of kilohertz (kHz) or an RF current having a frequency higher than the AC current. Considering the margin of the air pressure generated and maintained by the plasma, the frequency of the AC current is preferably 50 to 500 kilohertz (kHz).

When an AC voltage is applied to the driving electrode 53, the dielectric tube can function as a dielectric barrier on the one hand, and cause a dielectric barrier discharge inside the dielectric tube on the other. The solenoid coil 54 a may have a structure that covers the outside of the drive electrode 53. The number of coils or the formation area of the solenoid coil, and the intensity of the current flowing into the coil can be adjusted according to the area of the drive electrode and the diameter of the exhaust line, so as to generate a magnetic field of a size that can effectively prevent the problem of erosion of the inner surface of the dielectric tube. . In an embodiment of the present invention, the solenoid coil may be provided in the form of covering the entirety of the dielectric tube or may exceed the area of the dielectric tube. A plurality of solenoid coils may also be provided in a connected or separated configuration. . In an embodiment of the present invention, the solenoid coil may be in contact with the driving electrode in a form in which an electric wire is coated with an insulating film, or may be provided in a form separated from the driving electrode by a separate unit. In an embodiment of the present invention, if a current flows into the solenoid coil, a magnetic field is formed along the axial direction of the dielectric tube.

FIG. 9 shows a coupled state and a disassembled state of a plasma reactor using a Helmholtz coil as a magnetic field generator according to an embodiment of the present invention. The plasma reactor 50 includes a ground electrode 51, a dielectric tube 52, a driving electrode 53, and a Helmholtz coil 54b1, 54b2, and 54b3. When compared with a plasma reactor in which a solenoid coil is selected as a magnetic field generating section, the ground electrode, the dielectric tube, the drive electrode, and the case have the same structure and function. However, a Helmholtz coil 54b1 is used. 54b2, 54b3 replace the solenoid coil. The Helmholtz coils 54b1, 54b2, and 54b3 are composed of a plurality of coils provided at a distance equivalent to 1/2 of the diameter of the dielectric tube. The coils provided on the upper and lower portions can be set as follows: The upper and lower ends of the electric tube are separated by a distance corresponding to 1/2 of the diameter of the dielectric tube. Helmholtz coil can A magnetic field is generated inside the dielectric tube. The magnetic field formed along the axis of the dielectric tube can change the trajectory of the charged particles inside the plasma, reducing the incidence of the charged particles that hit the surface of the dielectric tube in a nearly vertical manner. Angle of incidence. The number of Helmholtz coils, the number of windings, and the intensity of the current flowing into the coil can be adjusted according to the length and diameter of the dielectric tube, the shape of the driving electrode, and the voltage, so as to generate effective prevention of the interior of the dielectric tube. The size of the magnetic field caused by the erosion of the surface.

FIG. 10 shows a coupled state and a disassembled state of a plasma reactor using a cylindrical permanent magnet as a magnetic field generating unit according to an embodiment of the present invention. The plasma reactor 50 includes a ground electrode 51, a dielectric tube 52, a driving electrode 53, and a permanent magnet 54c. In comparison with a plasma reactor in which a solenoid coil is selected as a magnetic field generating section, the ground electrode 51, the dielectric tube 52, the driving electrode 53, and the case 55 have the same structure and function, but are cylindrical. Instead of the solenoid coil. The cylindrical permanent magnet is arranged outside the dielectric tube in the form of covering the outside of the driving electrode. It can generate a magnetic field inside the dielectric tube. The magnetic field formed along the axis of the dielectric tube can cause the charged particles in the plasma. The motion trajectory of 发生 is changed to reduce the incident angle of the charged particles that hit the surface of the dielectric tube in a near-vertical manner. The magnetic flux of the cylindrical permanent magnet according to an embodiment of the present invention may be determined in consideration of the length and diameter of the dielectric tube, the shape and voltage of the driving electrode, and the like, so that the dielectric tube can be effectively prevented. The size of the magnetic field caused by the erosion of the internal surface.

According to an embodiment of the present invention, the magnetic field generating device provided outside the dielectric tube affects the life of the plasma reactor. In particular, when the exhaust gas contains a fluorine-based or chlorine-based gas, the plasma formed inside the dielectric tube contains highly reactive radicals, ions, and active species. The magnetic field generating portion of the present invention is in the dielectric tube. A magnetic field parallel to the axial direction is formed inside, so that the ion incident on the inner surface of the dielectric tube in a nearly vertical manner. The incident angle of the electrons is changed to reduce the erosion of the inner surface of the dielectric tube, so that the present invention can be practically applied in an operating environment that requires continuous operation for 24 hours and 365 days.

11a and 11b are diagrams for explaining that in a plasma reactor, a motion trajectory of a charged particle accelerated by an electric field is changed by a magnetic field generated by a magnetic field generating unit. Referring to FIG. 11 a, in a region where a driving electrode is provided, cations of the plasma are accelerated to be incident on the inner surface of the dielectric tube due to a negative voltage applied to the driving electrode and a wall charge formed on the surface of the dielectric tube. At this time, if a magnetic field is formed inside the plasma, the incident angle of the cations changes, as illustrated in Figure 11b. Referring to FIG. 11b, the ions 200 incident on the surface of the dielectric tube, that is, the “ceramic wall of the dielectric tube surface 100”, move toward the surface of the dielectric tube at a nearly vertical incidence angle. If a magnetic field B is formed inside the dielectric tube, The magnetic field changes the trajectory of the cations and is incident on the surface of the dielectric tube at an angle of incidence θ. At this time, according to the intensity of the magnetic field, the distribution function f _i ( E _K , θ ) of the ions that collide with the wall at the incident angle θ and the kinetic energy E _K can be determined by the Vlasov equation describing the plasma. Obtained by numerical calculation.

Figures 12a and 12b show potential and particle density distributions in a region of the plasma reactor adjacent to the inner surface of the dielectric tube. Referring to FIG. 12 a, if a plasmon in a quasi-charge neutral state is generated in a dielectric tube, electrons that are relatively much faster than cations collide with the dielectric wall surface more frequently. The surface of the dielectric body absorbs colliding electrons and assumes a negative potential, and thus forms an electric field along the wall surface direction. The electric field formed as described above reduces the electron flux toward the wall surface and increases the cation flux that hits the wall surface of the dielectric body. If the electron flux and the cation flux become the same, a charge will not be accumulated on the surface of the dielectric body to reach a steady state, and a self-bias will be formed on the internal surface of the dielectric body. The self-sufficient bias is represented by a sheath potential V _S.

[Formula 1]

In Formula 1, T _e is the equilibrium temperature of the electrons in the plasma, m _e, m _i is the mass of electrons and ions, respectively. For example, in a low pressure plasma T _e = 1eV, the fluoride ions (F ^-) or chloride ions (Cl ^-) in the case when the size of the sheath voltage V _S -10 V. In the area where the driving electrode is provided, the ions collide with the internal surface of the dielectric body by the external voltage applied to the electrode and the relative acceleration of the sheath voltage and acceleration, and cause sputtering or erosion of the surface of the dielectric body. . The spatial distribution of the cation density n _i and the electron density n _e near the surface of the dielectric is shown in Fig. 12b. The following area is called a Debye sheath, and the width is usually within a few mm: the quasi-charge neutral property of the plasma blocked near the surface of the dielectric is damaged, and cations are accumulated to form a negative potential on the surface. The surface of the dielectric body is curved because it is the inner surface of the cylinder, but the width of the Debye sheath and presheath is much smaller than the radius of the cylinder, so the surface of the dielectric body can be close to the plane and on the surface of the dielectric body. In the periphery, the movement of ions is greatly affected in the Debye sheath and the presheath.

For reference, in this case, the distribution function f _i ( E _K , θ ) of the ion over time is the deformed Frasov equation, which is the following formula 2, and the etch rate of the dielectric surface due to cations It can be defined by Equation 3 below.

In Equation 3, y ₀ ( E _K , θ ) represents an etching rate of a single ion having a kinetic energy E _K and a collision angle θ. α is the angle between the axial direction of the dielectric tube and the direction of the applied magnetic field, and ω = ω _c / ω _p represents the ratio of the cyclotron frequency ω _c to the plasma frequency ω _p .

13a and 13b show single charged particles due to the kinetic energy (E _K ) incident on the surface of the dielectric body and the angle of surface incidence (θ) in the presence of a magnetic field in the direction α relative to the dielectric tube axis. And the degree of etching of the dielectric surface caused by the sputtering of the charged particle flux. The following conditions can be learned through experiments: Generally, as shown probabilistically in Fig. 13a, the etch rate y ₀ ( E _K , θ ) of a single ion with kinetic energy E _K and collision angle θ is collided with the The kinetic energy of the ions increases in a proportional manner. If the etching rate gradually increases and reaches a maximum value due to the collision direction of the ions from the normal incidence (θ = 90 °) to the wall surface decreases by θ, it will be θ = 0 °, ie parallel to the wall surface The incidence rate is 0, and the etching rate becomes 0. There is a small difference in the collision angle in which the etching rate of a single ion has a maximum value according to the type of the ions, but it is roughly located around θ = 30 °. The application of a magnetic field is generally proposed for spatially confining the plasma, and has so far played a useful role. However, in the case of wall sputtering, the effect of the magnetic field is far more complicated than that described so far. If the magnetic field is simply applied to change the trajectory of the ion from normal incidence (θ = 90 °), such as As shown in Figure 13a, the sputtering effect is increased instead.

In order to avoid the situation and approaching parallel incidence (θ = 0 °), a strong magnetic field is required, so the situation is not a realistic countermeasure. The final etch rate of the dielectric surface of the ions to be obtained is expressed by Equation 3, which is a function of dividing the etch rate y ₀ ( E _K , θ ) of a single ion with the distribution function f _i ( E _K , θ After multiplication, consider the effect on the overall ion. The distribution function of ions depends on the incident ion flux and the collision between ions and electrons in the plasma. The ion flux is defined as the number of ions incident on the wall surface per unit time and unit area. It is roughly proportional to sinθ relative to the incident angle θ of the ions, so it decreases as it changes from normal incidence to parallel incidence. . This situation plays a role of locally reducing an increase in the etching rate y ₀ ( E _K , θ ) of a single ion. Fig. 13b shows a numerical calculation result of the etching rate with respect to the direction α of the magnetic field (Plasma Phys. Control. Fusion 50 (2008) 025009). Here, it can be known that in the case of α = 90 °, the etching rate does not depend on the strength of the magnetic field. When the direction of the magnetic field is parallel to the dielectric tube (α = 0 °), the etching rate is greatly reduced by 70%. about.

In Equation 4, when the direction of the magnetic field is parallel to the dielectric tube (α = 0 °), the etching rate Y (0, ω) can be expressed as the product of the incident ion flux and the etching rate of a single ion. A single ion is an angle θ _M = 30 ° representing a maximum etching rate, and the angle θ is a wall surface incident direction of an ion in an electric field perpendicular to the wall surface and a magnetic field in an axial direction near a wall of a cylinder. The angle can be expressed by θ = 90 ° -θ _H , θ _{H is} a Hall angle, and it is an angle between a current and an electric field in a magnetic field, and tan θ _H = ω _c τ. Here, Is the cyclotron frequency, τ represents the average collision time of ions in the plasma.

FIG. 14 shows changes in the surface etching rate of a dielectric body according to the strength of a magnetic field when a magnetic field parallel to the axis of the dielectric tube is applied, as compared to when there is no magnetic field. In the case of low-voltage plasma, the average collision time of ions is very long, so the product of the ion frequency and the plasma frequency is ω _p τ It is very large at about 5 × 10 ² . According to FIG. 14, when the intensity of the magnetic field is equivalent to about ω _c τ = 500 × ( ω _c / ω _p ) = 5, the etching rate is reduced by about 70%. For example, at low pressure plasma state, fluoride ions (F ^-) in the case when, plasma frequency Around, when the magnetic field strength is 0.02 T, the gyration frequency is . Therefore, ω _c τ Around 5, the magnetic field strength of 0.02 T is a magnetic field strength that can be easily achieved in practice, and therefore the present technology can be implemented very realistically.

Referring to FIG. 14, when a magnetic field in a direction parallel to the dielectric tube axis is applied to the plasma in the dielectric tube, only when the following conditions are achieved can the performance of improving the etching rate begin to be expressed: there is no magnetic field relative to the expected difference As the magnetic field strength increases, the etching rate initially increases gradually, so the intensity in the magnetic field is ω _c τ After reaching the maximum etch rate at 1, it should reach the satisfaction Magnetic field strength region. In the case of fluoride ions (F ^-) or chloride ions (Cl ^-) in the case when, corresponding to B 0.01 T. That is, when the strength of the magnetic field is less than 0.01 T, the etching rate will increase. Therefore, in order to reduce the etching rate, a power supply or a permanent magnet should be selected so that the magnetic field in the plasma region can be maintained stronger than 0.01 T.

If the theoretical and achievable results described above are applied to the plasma reactor of the present invention, a magnetic field that is substantially parallel to the axial direction of the dielectric tube is formed inside the dielectric tube by the proposed magnetic field generator. Therefore, it is possible to effectively reduce the etching rate (degree of erosion) on the surface of the dielectric body caused by the collision of ions inside the plasma.

The above description uses one embodiment to explain the technical idea of the present invention. Therefore, those skilled in the art in the technical field to which the present invention pertains can implement various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments described in the present invention are used to explain the technical idea of the present invention, rather than to limit the technical idea of the present invention, and the scope of the technical idea of the present invention is not limited to the embodiments. The hair The clear scope of protection should be interpreted according to the scope of the application, and all technical ideas within the same scope as the scope of the application should be interpreted to be included in the scope of rights of the present invention.

51‧‧‧ ground electrode

51a‧‧‧ flange

52‧‧‧ Dielectric

53a‧‧‧Elastic buffer section

53b‧‧‧drive electrode

54‧‧‧ Magnetic field generator

55‧‧‧shell

77‧‧‧Exhaust gas

88‧‧‧ exhaust

Claims (12)

A low-pressure plasma reactor for waste gas treatment is a method for decomposing exhaust gas discharged from a self-made process chamber. The low-pressure plasma reactor includes a dielectric tube for the exhaust gas to pass through, and a pair of ground electrodes. The extended form of the dielectric tube is located at both ends of the dielectric tube; the driving electrode is formed as a ring shape separated from the pair of ground electrodes and covering the outer surface of the dielectric tube in the longitudinal direction to connect In the AC power source section and the magnetic field generating section, in order to form a magnetic field in the longitudinal direction of the dielectric tube, it is configured to be insulated and coated on the outside of the driving electrode, and to alleviate the dielectric tube caused by ion sputtering Erosion of the inner surface of the housing; and the housing is in a form to prevent the exhaust gas from flowing to the outside when the crack of the dielectric tube is generated, and to block electromagnetic waves from radiating to the outside, and seal Covering the outside of the driving electrode and the outside of the magnetic field generating portion; and the magnetic field strength formed by the magnetic field generating portion along the length of the dielectric tube is limited to the formula (m _i : plasma ion mass, e: charge amount, τ: average collision time). The low-pressure plasma reactor for exhaust gas treatment according to item 1 of the scope of the patent application, wherein the low-pressure plasma reactor further includes a conductive elastic buffer portion for realizing the driving. The buffer and close contact between the electrode and the dielectric tube are interposed between the driving electrode and the dielectric tube. The low-pressure plasma reactor for exhaust gas treatment as described in the patent application item 2, wherein The conductive elastic buffer portion is a graphite sheet, a conductive polymer substance sheet, or a metal foam. The low-pressure plasma reactor for exhaust gas treatment according to item 1 of the scope of patent application, wherein the magnetic field generating portion is a solenoid coil, and the power is adjusted by a power source connected to the solenoid coil. Magnetic field strength. The low-pressure plasma reactor for exhaust gas treatment according to item 1 of the patent application scope, wherein the magnetic field generating portion is a Helmholtz coil, and is adjusted by a power source connected to the Helmholtz coil. The magnetic field strength. The scope of the patent term first low-pressure plasma reactor for the treatment of exhaust gases, where m _i is fluoride (F ^-) or chloride ions (Cl ^-) of the mass, The value is 0.01 T. The low-pressure plasma reactor for exhaust gas treatment according to item 1 of the scope of the patent application, wherein a portion where the ground electrode is in contact with the dielectric tube is a flange structure, and the housing is formed in a The dielectric tubes are arranged in a concentric manner in a cylindrical shape, and both ends of the casing are respectively connected to the flange structure, and the casing and the dielectric tube together form a double chamber. The low-pressure plasma reactor for exhaust gas treatment according to item 7 of the scope of patent application, wherein the dual chamber contains a cooling device using the atmosphere, nitrogen, or a coolant as a cooling medium. Low voltage plasma for exhaust gas treatment as described in patent application item 8 The reactor, wherein the cooling device is in the double chamber, and the cooling device includes a temperature sensor, a pressure sensor, or a temperature sensor and a pressure sensor, and the temperature sensor The measured value, the measured value of the pressure sensor or the measured value of the gas sensor feedback controls the degree of cooling. The low-pressure plasma reactor for exhaust gas treatment according to item 1 of the scope of the patent application, wherein the low-pressure plasma reactor is disposed between the process chamber and the vacuum pump, or constitutes an increase of the vacuum pump. Between the pressure pump and the support pump. The low-pressure plasma reactor for exhaust gas treatment according to item 1 of the scope of the patent application, wherein the housing further includes a sensor portion, and the sensor portion can sense a leak from the dielectric tube. The exhaust gas. A low-pressure plasma reactor for waste gas treatment, which decomposes the waste gas discharged from a self-made process chamber. The low-pressure plasma reactor includes a first ground electrode in the shape of a tube for the waste gas to pass through; One end portion of the dielectric tube is combined with the other end portion of the tube-shaped first ground electrode by a flange for the exhaust gas to pass through; a tube-shaped second ground electrode, the tube One end portion of the second ground electrode of the shape is combined with the other end portion of the dielectric tube by the flange for the exhaust gas to pass through; the driving electrode is formed to be grounded to the first shape of the tube An electrode is separated from the tube-shaped second ground electrode, and a ring shape covering an outer surface of the dielectric tube in a longitudinal direction is provided. State, connected to an AC power source unit; a magnetic field generating unit configured to form a magnetic field in the longitudinal direction of the dielectric tube, and is configured to be insulated and coated on the outside of the driving electrode; A cylindrical shape arranged in a concentric manner with the dielectric tube so as to seal and cover the outside of the driving electrode and the outside of the magnetic field generating portion, and both end faces of the housing are in contact with the flanges; One end of the tubular first ground electrode is connected to an exhaust port of a booster pump, and the booster pump exhausts the exhaust gas from an exhaust port of the process chamber. The supporting pump causes the exhaust gas to be discharged from the other end portion of the tubular second ground electrode. The casing and the dielectric tube form a dual chamber. The dual chamber includes an atmosphere, nitrogen, Or a cooling device is used as a cooling device for the cooling medium, the cooling device is in the double chamber, and the cooling device includes a temperature sensor, a pressure sensor, or a gas sensor.