Plasma device for treating exhaust gases

Abstract

The present application relates to waste gas treatment device, specifically to a kind of plasma device, the plasma device includes: plasma torch;Waste gas injection part, it is located in the lower portion of plasma torch;Reaction chamber, it is located in the lower portion of waste gas injection part;Plasma reaction part, it includes plasma torch and is arranged to supply cooling water to the cooling water chamber of reaction chamber;Cooling part, it is formed in the lower portion of plasma reaction part and mutually communicated with plasma reaction part, is equipped with passage and the cooling water chamber surrounding passage;Connecting portion, it connects cooling part and vacuum pump, wherein, connecting portion is equipped with for blocking the orifice of pressure drop by vacuum pump.The plasma device can maintain the pressure of the plasma reaction part of plasma device, including plasma torch, at a pressure close to atmospheric pressure by installing an orifice to block the pressure drop of the vacuum pump connected to the connecting portion, thus reducing the wear of the tungsten electrode within the plasma torch and prolonging the electrode life.

Description

Technical Field

[0001] This invention relates to waste gas treatment devices, and more specifically to a plasma device that can extend the electrode life of a plasma torch when connected to a vacuum pump. Background Technology

[0002] As industries such as semiconductors and LCDs become larger-scale and production increases, the types of gases used in their engineering are also increasing. Semiconductor manufacturing engineering involves many steps, and the types of gases used are as diverse as the many steps themselves.

[0003] For example, in semiconductor device manufacturing processes, wafers supplied to processing chambers undergo repeated photolithography, etching, diffusion, and metal deposition processes. These processes utilize various process gases, and after completion, waste gases are exhausted from the processing chamber via vacuum pumps. These waste gases may contain toxic components, therefore they are purified using waste gas treatment devices such as scrubbers before being discharged through the vacuum pumps.

[0004] With the increasing national semiconductor production and demand, South Korea's IT manufacturing processes are increasingly incorporating POU scrubber equipment to purify harmful gases emitted from equipment, and there is a need to introduce new technologies to address the performance degradation of existing equipment.

[0005] Therefore, this invention aims to describe a plasma-based perfluorinated compound (PFC) exhaust gas treatment device that can be integrated into various applications, such as primary POU scrubbers used for decomposing PFCs in semiconductor engineering exhaust gas treatment processes or for addressing the problem of frequent maintenance of vacuum pumps due to flames.

[0006] Specifically, the plasma-based waste gas treatment device includes a plasma reactor and a connecting part. The plasma reactor consists of a plasma torch located at the top, which decomposes waste gas containing perfluorinated compounds (PFCs) by passing it through nitrogen (N2) for plasma generation and a high-temperature plasma region connected to an electric generator when it flows in; a plasma chamber located at the bottom of the plasma torch; and a reaction water injection part configured to supply reaction water between the plasma torch and the plasma chamber. The connecting part is connected to the bottom of the plasma reactor and is used for moving the gas decomposed by the plasma reactor to a vacuum pump.

[0007] However, when this plasma-based waste gas treatment device is connected to a vacuum pump, the vacuum affects the plasma reactor through the connection of the waste gas treatment device. As a result, the tungsten used as the oxidation electrode in the plasma reactor vaporizes due to the low pressure, which lowers its boiling point, thus causing a decrease in lifespan / performance.

[0008] [Existing Technical Documents]

[0009] [Patent Documents]

[0010] Korean Patent No. 10-1142184 Summary of the Invention

[0011] Technical issues

[0012] The purpose of this invention is to provide a plasma device for treating waste gas that can extend electrode life even when connected to a vacuum pump.

[0013] Technical solution

[0014] To achieve the above objectives, the present invention provides a plasma device for treating waste gas. The plasma device according to the present invention is a plasma device for treating waste gas connected to a vacuum pump, comprising: a plasma torch; a waste gas injection section disposed at the lower part of the plasma torch; a reaction chamber disposed at the lower part of the waste gas injection section; a plasma reaction section including the plasma torch and a cooling water chamber configured to supply cooling water to the reaction chamber; a cooling section formed at the lower part of the plasma reaction section and communicating with the plasma reaction section, having a channel and a cooling water chamber surrounding the channel; and a connecting section connecting the cooling section and the vacuum pump.

[0015] The connecting part may be provided with an orifice for blocking the pressure drop caused by the vacuum pump.

[0016] The orifice may include a body that blocks the channel of the connection and at least one orifice formed in a portion of the body.

[0017] The size of the orifice can be increased proportionally with the inflow rate of the exhaust gas.

[0018] The plasma torch, waste gas injection section, and reaction chamber of the plasma reaction section can be integrated into one unit.

[0019] The plasma torch may include: a cathode electrode having a solid internal cylindrical shape; a cathode electrode body formed to surround the cathode electrode, having a bulging portion at the bottom; a housing covering the cathode electrode and the upper part of the cathode electrode body; an anode electrode body disposed at the lower part of the cathode electrode body and spaced at a predetermined distance; a plasma generating gas supply unit disposed between the cathode electrode body and the anode electrode body, supplying plasma generating gas for generating plasma; and a cooling water supply unit supplying cooling water to the cathode electrode body and the anode electrode body.

[0020] One end of the lower part of the cathode electrode may be exposed in a predetermined portion of the cathode electrode body.

[0021] The interior of the bulge may be formed with an arc generating section consisting of cylindrical grooves that generate vortices of plasma-generating gas.

[0022] The interior of the anode electrode body may have a cylindrical discharge section with a diameter that tends to increase downwards.

[0023] The plasma generating gas supply unit may include: a main body having a ring shape and an internal space; and a plasma generating gas injection pipe formed in the main body for injecting gas.

[0024] The plasma-generating gas injection tube is formed to be tangent to the circumferential direction of the internal space of the main body, and the two plasma-generating gas injection tubes can be configured to form a 180° angle.

[0025] The diameter of the gas outlet of the plasma-generating gas injection tube can be smaller than the diameter of the gas injection port.

[0026] The cooling water inlet in the cooling water chamber of the reaction chamber and the cooling section can be located at the lowest end of the cooling water chamber, and the cooling water outlet can be located at the highest end of the cooling water chamber to prevent the formation of gas bubbles.

[0027] Technical effect

[0028] According to the plasma device of the present invention, by installing an orifice at the connection part connected to the vacuum pump to block the pressure drop of the vacuum pump, the pressure of the plasma reaction section of the plasma device, including the plasma torch, can be maintained at a pressure close to atmospheric pressure, thereby reducing the wear of the tungsten electrode inside the plasma torch and extending the electrode life.

[0029] Furthermore, the plasma torch in the plasma device according to the present invention can generate gas at high speed by rotating the cylindrical arc generating part formed at the lower part of the cathode electrode body to form a strong eddy current, thus maintaining accurate and stable plasma. Even when operating at low power, it can improve gas handling efficiency. It can maintain a constant plasma by rotating the plasma generating part formed at the cathode electrode body to generate gas, thus reducing electrode wear and extending electrode life. Attached Figure Description

[0030] Figure 1 This is a schematic diagram illustrating the state in which a plasma device for treating waste gas according to an embodiment of the present invention is connected to a vacuum pump.

[0031] Figure 2 A simplified schematic diagram of a plasma device for treating waste gas according to an embodiment of the present invention is provided.

[0032] Figure 3A perspective view showing a plasma torch, which is a component of a plasma device according to an embodiment of the present invention;

[0033] Figure 4 A cross-sectional view showing a plasma torch, which is a component of a plasma device according to an embodiment of the present invention;

[0034] Figure 5 A schematic diagram showing the gas supply section of a plasma torch, which is a component of a plasma apparatus according to an embodiment of the present invention.

[0035] Figure 6 A schematic diagram illustrating the flow of plasma-generating gas inside a plasma torch, which is a component of a plasma device according to an embodiment of the present invention.

[0036] Figure 7 A schematic diagram illustrating the measurement of the wear length of a tungsten electrode inside a plasma torch, which is a component of a plasma apparatus according to an embodiment of the present invention.

[0037] Figure 8 A graph showing the wear length of the tungsten electrode inside the plasma torch over operating time when the plasma device according to an embodiment of the present invention does not include the orifice as a component.

[0038] Figure 9 Photographs showing the wear of tungsten electrodes inside a plasma torch under normal pressure over time (after approximately 250 days of operation) when the plasma apparatus according to an embodiment of the present invention does not include an orifice as a component.

[0039] Figure 10 Photographs showing the wear of the tungsten electrode inside the plasma torch under normal pressure over time (after approximately 600 days of operation) when the plasma apparatus according to an embodiment of the present invention does not include the orifice as a component.

[0040] Figure 11 Photographs showing the wear state of the tungsten electrode inside the plasma torch as of operating time, with an orifice as a component of a plasma device according to an embodiment of the present invention (day 2, after 20 hours of operation).

[0041] Figure 12 The photograph illustrates the wear state of the tungsten electrode inside the plasma torch as of operating time, in the case of an orifice as a component of a plasma device according to an embodiment of the present invention (day 3, after 28 hours of operation).

[0042] Explanation of reference numerals in the attached figures

[0043] 100: Plasma device; 10: Plasma reaction section

[0044] 11: Plasma torch 12: Exhaust gas injection section

[0045] 13: Reaction chamber; 14: Cooling water chamber

[0046] 20: Cooling section 21: Movement channel

[0047] 22: Cooling water chamber

[0048] 23, 25: Cooling water inlet; 24, 26: Cooling water outlet.

[0049] 30: Connecting part; 31: Orifice

[0050] 110: Cathode electrode; 120: Cathode electrode body

[0051] 121: Electrode receiving hole; 122: Bulging part

[0052] 123: Arc generating part; 130: Housing

[0053] 140: Anode electrode body; 141: Discharge section

[0054] 142: First discharge section; 143: Second discharge section

[0055] 144: Third discharge section; 145: First inclined section

[0056] 146: Second inclined part; 147: Protrusion.

[0057] 150: Plasma generating gas supply unit; 151: Main body

[0058] 152: Plasma generating gas injection pipe; 153: Plasma generating gas injection port

[0059] 154: Plasma generation gas exhaust port

[0060] 160: Cooling water supply section; 161: Cooling holes

[0061] 162: Cooling water inlet 163: Cooling water outlet

[0062] 170: First insulating part; 180: Second insulating part Detailed Implementation

[0063] This invention can be modified in various ways and may have various embodiments. Specific embodiments are illustrated in the figures and detailed descriptions are provided in the detailed embodiments. However, it should be understood that this is not intended to limit the invention to specific embodiments, and may include all variations, equivalents, and even substitutions encompassed within the spirit and technical scope of this invention. In describing this invention, detailed descriptions of relevant prior art are omitted where it is deemed that such descriptions might obscure the spirit of the invention.

[0064] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. When describing the drawings, the same or corresponding constituent elements will be marked with the same reference numerals and repeated descriptions will be omitted.

[0065] Figure 1 This is a schematic diagram illustrating the state in which a plasma device for treating waste gas according to an embodiment of the present invention is connected to a vacuum pump.

[0066] See Figure 1 The plasma device 100 according to the present invention can be a waste gas treatment device for treating waste gases generated in semiconductor engineering and moving towards a vacuum pump. The plasma device 100 according to the present invention can also be used to prevent by-products caused by special gases discharged into the vacuum pump during semiconductor main engineering from flowing into the vacuum pump and causing problems such as pump maintenance and equipment operation. Therefore, it can improve pump maintenance and equipment operation efficiency and extend the vacuum pump's V / P Life Time.

[0067] Figure 2 A simplified schematic diagram of a plasma device for treating waste gas according to an embodiment of the present invention is provided.

[0068] See Figure 2 The plasma device 100 for treating waste gas according to the present invention includes a plasma reaction section 10, a cooling section 20 and a connecting section 30.

[0069] The plasma reaction unit 10 includes a plasma torch 11, an exhaust gas injection unit 12 located at the lower part of the plasma torch, a reaction chamber 13 located at the lower part of the exhaust gas injection unit, and a cooling water chamber 14 configured to supply cooling water to the plasma torch and the reaction chamber.

[0070] The plasma torch 11 may be a plasma torch known in the art, such as an RF plasma torch, a microwave plasma torch, an arc plasma torch, etc., but is not limited thereto.

[0071] Preferably, the plasma torch can be an electric arc plasma torch, which can be configured as follows.

[0072] Figure 3 A perspective view is provided for illustrating a plasma torch, which is a component of a plasma apparatus according to an embodiment of the present invention. Figure 4 A cross-sectional view showing a plasma torch, which is a component of a plasma device according to an embodiment of the present invention.

[0073] See Figure 3 and Figure 4 The plasma torch 11 according to the present invention includes a cathode electrode 110, a cathode electrode body 120, a housing 130, an anode electrode body 140, a plasma generating gas supply unit 150, and a cooling water supply unit 160.

[0074] The cathode electrode 110 may have an elongated cylindrical shape with a solid interior, extending upwards and downwards. The upper end face of the cathode electrode 110 has a flat shape, but the lower end face may have a hemispherical shape bulging downwards. This is to ensure that when the plasma generating gas supplied from the gas supply section 150 rotates to form a vortex at the lower part of the cathode electrode 110, the formation of the vortex is not hindered, thus ensuring that the vortex can be formed effectively.

[0075] Furthermore, tungsten is preferably the material of the cathode electrode 110. Conventionally, to manufacture tungsten-containing cathode electrodes 110, tungsten powder is condensed at high temperatures to form a mold, resulting in a weak material and a shortened lifespan during plasma torch operation. However, the cathode electrode 110 of the present invention is not manufactured using the conventional method of condensing tungsten powder at high temperatures, but rather using pure tungsten. Therefore, a stronger cathode electrode than conventional ones can be manufactured, thereby extending the lifespan of the cathode electrode 110.

[0076] The cathode electrode body 120 may be formed to surround the cathode electrode 110. An electrode receiving hole 121 may be formed in the center of the interior of the cathode electrode body 120 to receive the cathode electrode 110. Furthermore, the lower part of the cathode electrode body 120 includes a bulge 122 that bulges downwards, and an arc generating part 123, composed of a cylindrical groove, may be formed inside the bulge 122 to generate a vortex of plasma-generating gas. That is, the electrode receiving hole 121 formed inside the cathode electrode body 120 and the arc generating part 123 formed in the lower part can communicate with each other. Preferably, the diameter of the formed arc generating part 123 is larger than the diameter of the electrode receiving hole 121.

[0077] The cathode electrode 110 is inserted into the electrode receiving hole 121 installed in the cathode electrode body 120, and can be configured such that the lower end face of the cathode electrode 110, that is, the hemispherical bulge at the lower part of the cathode electrode 110, is exposed to the arc generating part 123 of the cathode electrode body 120. Therefore, the arc generating part 123 of the cathode electrode body 120 can be in a shape that surrounds the lower end face of the cathode electrode 110.

[0078] Furthermore, the cathode electrode body 120 may include a cooling water supply section 160 for cooling water to flow inside the cathode electrode body 120 to cool the heat generated by the plasma. The cooling water supply section 160 may include cooling holes 161 formed inside the cathode electrode body 120 to allow cooling water to flow into the cathode electrode body 120, a cooling water inlet 162 formed to inject cooling water into the cathode electrode body 120, and a cooling water outlet 163 to allow the cooling water to flow inside the cathode electrode body 120 for cooling and then discharge it.

[0079] The housing 130 can cover the other end of the cathode electrode 110 and the upper part of the cathode electrode body 120. Furthermore, the housing 130 can be formed of an insulating material. Here, the insulating material can be formed of polyvinyl chloride, Teflon, ceramic, etc. Therefore, the housing 130 can effectively insulate the cathode electrode 110 and the cathode electrode body 120.

[0080] The anode electrode 140 is disposed at the lower part of the cathode electrode 120 at a predetermined distance from its lower portion. The upper part of the anode electrode 140 is positioned apart from the cathode electrode 120, serving as a (+) polarity electrode to contain the electric arc generated by the cathode electrode 120. Preferably, the anode electrode 140 is formed of copper, which has high conductivity. Furthermore, the interior of the anode electrode 140 may include a discharge section 141 for discharging gases, nitrogen, and plasma generated after the thermal decomposition reaction.

[0081] The discharge portion 141 of the anode electrode body 140 can be formed into a cylindrical shape, and the diameter of the discharge portion 141 gradually widens in the downward direction, and can be divided into a first discharge portion 142, a second discharge portion 143, and a third discharge portion 144. That is, the diameter of the second discharge portion 143 can be larger than the diameter of the first discharge portion 142, and the diameter of the third discharge portion 144 can be larger than the diameter of the second discharge portion 143.

[0082] To ensure that the diameter of the second discharge section 143 is larger than the diameter of the first discharge section 142, a first inclined portion 145 may be formed between the second discharge section 143 and the first discharge section 142. That is, the first inclined portion 145 may be formed with an inclination such that its diameter tends to increase in the downward direction. Preferably, the first inclined portion 145 may have an inclination of 130° to 150°, increasing the contact area between the discharged gas and the discharge section 141 when the plasma generating gas is discharged, thereby enabling high-speed rotation inside to effectively generate vortices. More preferably, the inclined portion may have an inclination of 140°. Furthermore, the diameter of the third discharge section 144 may be larger than the diameters of the first discharge section 142 and the second discharge section 143. That is, to ensure that the diameter of the third discharge section 144 is larger than the diameter of the second discharge section 143, a second inclined portion 146 may be formed between the third discharge section 144 and the second discharge section 143.

[0083] As described above, the size of the discharge portion 141 of the anode electrode body 140 of the plasma torch 11 according to the present invention is divided into three levels, and inclined surfaces 145 and 146 are formed between each discharge portion 142, 143, and 144 to expand the discharge portion 141. This maximizes the contact area between the discharged gas and the discharge portion 141, allowing the discharged gas to be discharged while rotating at high speed inside the discharge portion 141. This high-speed rotating discharged gas can form a strong vortex inside the discharge portion 141, thus enabling efficient treatment of waste gas even at low power, thereby saving energy consumption.

[0084] Furthermore, a protrusion 147 may be formed on the upper part of the anode electrode body 140, causing the periphery of the discharge part 141 to protrude. The protrusion 147 of the anode electrode body 140 can serve as a guide, allowing the gas injected from the gas supply part 150 to enter at high speed toward the arc generating part 123 of the cathode electrode body 120.

[0085] Similar to the cathode electrode 120, the interior of the anode electrode 140 may include a cooling water supply section 160 for circulating cooling water inside the anode electrode 140 to cool the heat generated by the plasma. The cooling water supply section 160 may include cooling holes 161 formed inside the anode electrode 140 to allow cooling water to flow inside, a cooling water inlet 162 for injecting cooling water into the anode electrode 140, and a cooling water outlet 163 for allowing cooling water to flow inside the anode electrode 140 for cooling and then discharge. That is, the cooling water supply section 160 may be formed in both the cathode electrode 120 and the anode electrode 140.

[0086] The plasma generating gas supply unit 150 can be arranged in a ring between the cathode electrode body 120 and the anode electrode body 140. More specifically, the plasma generating gas supply unit 150 can be configured to fit into the bulge 122 of the cathode electrode body 120.

[0087] The plasma generating gas supply unit 150 is capable of supplying plasma generating gas into the torch for generating plasma inside the plasma torch 11. As an example, the plasma generating gas can be N2 gas.

[0088] Furthermore, the plasma generating gas supply unit 150 may include a cylindrical body 151 with an internal space and a plasma generating gas injection pipe 152 formed in the body 151 and injected with plasma generating gas.

[0089] Figure 5 This is a schematic diagram illustrating the plasma generating gas supply section 150 of a plasma torch according to an embodiment of the present invention.

[0090] See Figure 5 The main body 151 of the plasma generating gas supply unit 150 has a ring shape with an internal space, and can be installed into the bulge 122 of the cathode electrode body 120.

[0091] The plasma generating gas injection pipe 152 of the plasma generating gas supply unit 150 is as follows: Figure 5 As shown, preferably, the two plasma gas injection pipes 152 are arranged tangent to the circumferential direction of the internal space of the main body 151, forming a 180° angle between them. Furthermore, to increase the discharge pressure of the gas discharged through the plasma gas injection pipes 152, the diameter of the plasma gas discharge port 154 of the plasma gas injection pipe 152 can be smaller than the diameter of the plasma gas injection port 153. That is, since the diameter of the plasma gas discharge port 154 is smaller than the diameter of the plasma gas injection port 153 of the plasma gas injection pipe 152, the gas powerfully ejected through the plasma gas discharge port 154 can form a strong vortex through the gas injection pipes 152 arranged 180° apart.

[0092] Regarding the position of the plasma generating gas outlet 154 of the plasma generating gas injection pipe 152, it is preferable that the plasma generating gas supply section 150 is inserted into the bulge 122 of the cathode electrode body 120, and the plasma generating gas outlet 154 faces the bulge 122. This is so that the exhaust gas ejected from the gas outlet 154 flows along the bulge 122 of the cathode electrode body 120, thereby inducing the gas to flow towards the arc generating section 123 of the cathode electrode body 120.

[0093] Figure 6A schematic diagram illustrating the flow of plasma-generating gas inside a plasma torch in the plasma apparatus according to the present invention.

[0094] See Figure 6 Plasma generating gas, injected through the plasma generating gas supply unit 150, is injected into the main body 151 through two plasma generating gas injection pipes 152 of the plasma generating gas supply unit 150. The injected gas forcefully enters the arc generating unit 123 of the cathode electrode body 120 through the bulge 122 of the cathode electrode body 120 and the protrusion 147 of the anode electrode body 140. The gas forcefully entering the arc generating unit 123 generates a strong vortex as the cylindrical arc generating unit 123 rotates at high speed. This vortex enables the maintenance of stable plasma during plasma generation, thus improving gas processing efficiency even during low-power operation.

[0095] Furthermore, when the vortex of the plasma-generating gas is weak, electrode wear can occur at the point where an electric arc occurs during plasma discharge. However, according to an embodiment of the present invention... Figure 5 and Figure 6 The plasma torch can maintain a constant plasma by generating strong eddy currents through a powerful gas injection pipe 152 and a groove-shaped arc generating section 123 structure formed at the lower part of the cathode electrode body 120, thus reducing electrode wear. Therefore, compared with existing plasma torches, the electrode life can be extended by more than twice.

[0096] See you again Figure 3 and Figure 4 The upper and lower parts of the anode electrode body 140 may also include a first insulating part 170 and a second insulating part 180.

[0097] The first insulating portion 170 may be formed as a protrusion 147 covering the anode electrode body 140. The first insulating portion 170, positioned below the gas supply section 150, serves to maintain the distance between the cathode electrode body 120 and the anode electrode body 140 by providing mutual insulation. The first insulating portion 170 may be made of an insulating material with excellent heat resistance and rigidity, but is not limited to this.

[0098] The second insulating portion 180 may be formed to surround the lower part of the anode electrode body 140. The second insulating portion 180 is disposed between the anode electrode body 140 and the plate supporting the anode electrode body 140, thereby achieving insulation between the anode electrode body 140 and the plate. The material of the second insulating portion 180 may be an insulating material with excellent heat resistance and rigidity, but is not limited thereto.

[0099] The plasma generated by the plasma torch moves through a vortex toward the reaction chamber 13 located at the lower part of the plasma torch.

[0100] In addition, an exhaust gas injection section 12 is formed between the plasma torch and the reaction chamber. The exhaust gas injected from the exhaust gas injection section 12 moves toward the reaction chamber 13 located at the lower part of the exhaust gas injection section.

[0101] In the reaction chamber 13, the waste gas injected from the waste gas injection section 12 reacts with the plasma, and the perfluorinated compounds can be decomposed by the plasma to generate decomposition gas.

[0102] That is, according to the present invention, the plasma reaction section is provided with a reaction chamber 13, and the exhaust gas is not directly injected into the plasma torch, but enters the reaction chamber 13 located at the lower part of the plasma torch, so as not to affect the electrodes of the plasma torch, thereby improving the life of the electrodes of the plasma torch.

[0103] The decomposition gas exists in a high-temperature state due to the high-temperature plasma. In order to be discharged to the outside, it is first cooled by the cooling water in the cooling water chamber 14 formed in the reaction chamber 13, and then moves to the cooling section 20 located at the lower end of the reaction chamber 13.

[0104] The cooling water chamber 14 is configured to supply cooling water to the walls of the plasma torch, the reaction chamber, and the cooling section described below. Here, the cooling water chamber located within the plasma torch includes the aforementioned cooling water supply section 160, cooling hole 161, cooling water inlet 162, and cooling water outlet 163, as detailed above.

[0105] In the cooling water chamber 14 formed within the reaction chamber 13, to prevent the formation of gas bubbles, it is preferable to perform gas cooling from the bottom. Therefore, the cooling water chamber 14 provided in the reaction chamber 13 can have the cooling water inlet 25 located at the bottom of the cooling water chamber and the cooling water outlet 26 located at the top of the cooling water chamber, but is not limited thereto.

[0106] The plasma reaction unit can be manufactured as a single unit, comprising the plasma torch 11, the waste gas injection unit 12, and the reaction chamber 13, to stably perform plasma formation and reaction.

[0107] The cooling section 20 is located at the lower part of the plasma reaction section 10 and communicates with it. Its function is to cool the gas that has been decomposed by the plasma reaction section before it moves to the vacuum pump. For the purpose of cooling the internal tubes, the cooling section 20 can be composed of a double-structure elbow section of the moving channel 21 and the cooling water chamber 22.

[0108] Here, in order to prevent gas bubbles from forming, it is preferable to perform gas cooling from the bottom. Therefore, in order to prevent gas bubbles from forming, the cooling water chamber 22 provided in the cooling section 20 may have the cooling water inlet 23 located at the end (bottom) of the cooling water chamber and the cooling water outlet 24 located at the top of the cooling water chamber, but is not limited to this.

[0109] The connecting part 30 is the part that connects the plasma device to the vacuum pump.

[0110] However, the vacuum pump remains at 10 -3 The vacuum level of Torr, therefore, when the plasma device according to the invention is directly connected to the vacuum pump, a vacuum level of approximately 10 is also formed inside the plasma reaction section through the connection part of the plasma device. - 3 The vacuum level of the Torr causes the tungsten electrode inside the plasma torch to vaporize due to the lower boiling point caused by the low pressure, resulting in a decrease in lifespan / performance.

[0111] In response, the inventors of this invention discovered during their research on methods to prevent pressure drops within the plasma device caused by a vacuum pump that by providing an orifice 31 in the connection portion 30 to control the gas flow rate and prevent pressure drops inside the plasma reaction section including the plasma torch, tungsten electrode vaporization within the plasma torch can be suppressed, thereby improving its lifespan.

[0112] Therefore, the plasma device according to the present invention is characterized in that the connecting portion 30 has an opening 31.

[0113] The orifice 31 includes a main body that blocks the channel of the connection and an orifice formed in a part of the main body.

[0114] At least one of the aforementioned orifices can be formed, and the size of the orifice can be configured to counteract a vacuum. For example, the orifice can be a circle with a diameter of 3 to 5 mm, but can be increased proportionally to the inflow rate of the exhaust gas. However, if the size of the orifice is too large relative to the inflow rate of the exhaust gas, the effect of preventing pressure drop decreases, thus causing the tungsten electrode in the plasma torch to vaporize and continuously wear down.

[0115] The present invention will be described in more detail below through experiments. The following experimental examples are for illustrative purposes only, and the scope of the invention is not limited thereto.

[0116] Experimental Example

[0117] To determine the effect of the orifice provided in the connection part 30 on the wear of the tungsten electrode inside the plasma torch when the plasma device of the present invention with a plasma torch is connected to a vacuum pump, the following experiment was conducted.

[0118] like Figure 2 As shown, a plasma device has been manufactured that includes a plasma reaction section 10, a cooling section 20 formed in the lower part of the plasma reaction section and communicating therewith, and a connecting section 30. The plasma reaction section 10 includes a plasma torch 11, an exhaust gas injection section 12 provided in the lower part of the plasma torch, a reaction chamber 13 provided in the lower part of the exhaust gas injection section, and a cooling water chamber 14 provided to supply cooling water to the plasma torch and the reaction chamber.

[0119] In the plasma device, the wear length of the tungsten electrode inside the plasma torch was measured over time, both when an orifice was installed on the connection and when the plasma device was not installed, during the process of connecting to the vacuum pump and driving the plasma device.

[0120] Figure 7 This is a schematic diagram illustrating the measurement of the wear length of a tungsten electrode inside a plasma torch, which is a component of a plasma device according to an embodiment of the present invention.

[0121] The wear length of the tungsten electrode is as follows: Figure 7 The figure shows the difference between the length of the tungsten electrode before device activation and the length of the tungsten electrode after device activation. The tungsten electrode is considered to have reached the end of its lifespan when it wears 15 mm.

[0122] First, for cases where no orifice was installed at the connection point, the wear length of the tungsten electrode inside the plasma torch was measured as the plasma device operated over time, as shown in Table 1. Figure 8 As shown, the plasma device operates for an average of about 10 hours per day.

[0123] Table 1

[0124]

[0125] Figure 8 This is a graph showing the wear length of the tungsten electrode inside the plasma torch as the plasma device connected to the vacuum pump operates during operation, without an orifice installed as a component in the connection portion in a plasma device according to an embodiment of the present invention.

[0126] As shown in Table 1 and Figure 8As shown, when the connection part of the plasma device according to the present invention is not equipped with an orifice, the tungsten electrode of the plasma torch reaches the end of its life after 81 hours (about 8 days) and the plasma device connected to the vacuum pump can no longer be used in engineering.

[0127] In addition, as a comparative example, without installing the mounting hole at the connection portion of the plasma device according to the present invention, the plasma device was placed in a semiconductor engineering facility at atmospheric pressure and operated. The wear length of the tungsten electrode inside the plasma torch was then measured over the operating time, as shown in Table 2. The plasma device operated for approximately 600 days.

[0128] Table 2

[0129]

[0130] Figure 9 To illustrate the wear condition of the tungsten electrode inside the plasma torch after approximately 250 days of operation at atmospheric pressure, when the plasma apparatus according to an embodiment of the present invention does not include the orifice as a component, Figure 10 This photograph shows the wear condition of the tungsten electrodes inside the plasma torch after approximately 600 days of operation.

[0131] As shown in Table 2, Figure 9 and Figure 10 As shown, even without the installation port at the connection part of the plasma device according to the present invention, when the plasma device under normal pressure is applied to semiconductor engineering operation, the wear length of the tungsten electrode inside the plasma torch is still less than 0.5 mm after 250 days and 600 days, and the tungsten electrode hardly wears at all.

[0132] Subsequently, according to an embodiment of the plasma device of the present invention, after the mounting orifice of the connecting part was installed, the wear length of the tungsten electrode inside the plasma torch, which occurred with the operating time of the plasma device connected to the vacuum pump, was measured, as shown in Table 3. Figure 11 and Figure 12 As shown.

[0133] Table 3

[0134]

[0135] Figure 11 To show the wear condition of the tungsten electrode inside the plasma torch after 2 days and 20 hours of operation with an orifice installed at the connection part of the plasma device according to an embodiment of the present invention, Figure 12 This is a photograph of the wear condition of the tungsten electrodes inside the plasma torch after 28 hours of operation on day 3.

[0136] As shown in Table 3, Figure 11 and Figure 12 As shown, when an orifice is installed at the connection of the plasma device according to the present invention, the wear length of the tungsten electrode connected to the vacuum pump is still less than 1 mm after 3 days, which is the same as the wear degree of the tungsten electrode under normal pressure. Therefore, it can be seen that by installing an orifice at the connection of the plasma device, the pressure of the plasma device can be maintained at approximately normal pressure by preventing pressure drop.

[0137] Therefore, the plasma device according to the present invention can maintain the pressure of the plasma reaction section of the plasma device, including the plasma torch, at close to atmospheric pressure by blocking the low pressure of the vacuum pump through the mounting orifice at the connection part for connection with the vacuum pump, thereby reducing the wear of the tungsten electrode in the plasma torch and extending the electrode life.

[0138] Furthermore, the plasma torch in the plasma device according to the present invention forms a strong vortex by rotating the plasma-generating gas at high speed through the cylindrical arc-generating part formed at the lower part of the cathode electrode body, thus maintaining a precise and stable plasma and improving gas handling efficiency even when operating at low power. By rotating the plasma-generating gas through the arc-generating part formed on the cathode electrode body to maintain a constant plasma, electrode wear can be reduced and electrode life extended.

[0139] Furthermore, the embodiments of the present invention disclosed in this specification and figures are merely specific examples provided to aid understanding and are not intended to limit the scope of the invention. Other modifications based on the technical concept of the present invention can be implemented beyond the disclosed embodiments, which will be apparent to those skilled in the art.

Claims

1. A plasma device, which is a plasma device for treating exhaust gas connected to a vacuum pump, characterized by comprising: The plasma device comprises: a plasma torch; an exhaust gas injection portion provided at a lower portion of the plasma torch; a reaction chamber provided at a lower portion of the exhaust gas injection portion; a plasma reaction portion including the plasma torch and a cooling water chamber configured to supply cooling water to the reaction chamber; a cooling portion formed at a lower portion of the plasma reaction portion and in communication with the plasma reaction portion, provided with a passage and a cooling water chamber surrounding the passage; and a connection portion connecting the cooling portion and a vacuum pump, wherein the connection portion is provided with an orifice for blocking a pressure drop by the vacuum pump, the orifice having a shape of a tube protruding from an end portion of the connection portion toward the cooling portion.

2. The plasma device according to claim 1, wherein: the orifice includes a main body blocking the passage of the connection portion and at least one orifice hole formed at a portion of the main body.

3. The plasma device according to claim 2, wherein: a size of the orifice hole increases in proportion to an inflow rate of the exhaust gas.

4. The plasma device according to claim 1, wherein: the plasma torch, the exhaust gas injection portion, and the reaction chamber of the plasma reaction portion are formed in one body.

5. The plasma device of claim 1, wherein, The plasma torch includes: a cathode electrode having a columnar shape with an inner portion being solid; a cathode electrode body formed to surround the cathode electrode, having a bulging portion bulging at a lower portion; a housing covering an upper portion of the cathode electrode and the cathode electrode body; an anode electrode body disposed at a lower portion of the cathode electrode body at a predetermined distance; a plasma generation gas supply portion disposed between the cathode electrode body and the anode electrode body to supply a plasma generation gas for generating a plasma; and a cooling water supply portion supplying cooling water to the cathode electrode body and the anode electrode body.

6. The plasma device according to claim 5, wherein: one end of the lower portion of the cathode electrode is exposed by a predetermined portion at the cathode electrode body.

7. The plasma device according to claim 5, wherein: an arc generation portion in which a vortex of the plasma generation gas is generated is formed at an inner portion of the bulging portion in a cylindrical shape.

8. The plasma device according to claim 5, wherein: a cylindrical discharge portion having a diameter increasing toward a lower portion is formed at an inner portion of the anode electrode body.

9. The plasma device of claim 5, wherein, The plasma generation gas supply portion includes: a main body having a ring shape and an inner portion formed with a space; and a plasma generation gas injection tube formed at the main body to inject the gas.

10. The plasma device according to claim 9, wherein: the plasma generation gas injection tube is formed to be tangent to a circumferential direction of the inner space of the main body, and two plasma generation gas injection tubes are disposed to constitute 180°.

11. The plasma device according to claim 9, wherein: a diameter of a gas discharge port of the plasma generation gas injection tube is smaller than a diameter of a gas injection port.

12. The plasma device according to claim 1, wherein: The cooling water inlet of the cooling water chamber provided in the reaction chamber and the cooling part is provided at the lowermost end of the cooling water chamber, and the cooling water outlet is provided at the uppermost end of the cooling water chamber to prevent the formation of gas bubbles.

Images