Patent ID: 12243724

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, specific embodiments will be described in more detail with reference to the accompanying drawings. The present invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. In the descriptions, the same elements are denoted with the same reference numerals. In the figures, the dimensions of layers and regions are exaggerated for clarity of illustration. Like reference numerals refer to like elements throughout.

FIG.1is a cross-sectional view of a batch type substrate processing apparatus in accordance with an exemplary embodiment.

Referring toFIG.1, a batch type substrate processing apparatus100in accordance with an exemplary embodiment may include a reaction tube110having a processing space111, in which a plurality of substrates10are accommodated, a plurality of electrodes121and122extending in a longitudinal direction of the reaction tube110and spaced apart from each other, and an electrode protection part130that protects the plurality of electrodes121and122.

The reaction tube110may have a cylindrical shape with a closed upper portion and an opened lower portion, made of a heat resistance material such as quartz or ceramic, and may provide the processing space111in which the plurality of substrates10are accommodated to be processed. The processing space of the reaction tube110may be a space in which the substrate boat, on which the plurality of substrates10are loaded in the longitudinal direction of the reaction tube110, are accommodated, and also, an actual processing process (for example, a deposition process) is performed.

Here, the substrate boat may be configured to support the substrates10and be provided so that the plurality of substrates10are loaded in the longitudinal direction (i.e., a vertical direction) of the reaction tube110and also provide a plurality of processing spaces in which the plurality of substrates10are individually processed.

The plurality of electrodes121and122may extend along the longitudinal direction of the reaction tube110and may be spaced apart from each other. For example, each of the plurality of electrodes121and122may have a bar shape extending along the longitudinal direction of the reaction tube110, may be arranged side by side (or parallel to each other), and may be spaced apart from each other along a circumferential direction of the reaction tube110.

Here, the plurality of electrodes121and122may include first and second power supply electrodes121aand121bspaced apart from each other, and a ground electrode122provided between the first power supply electrode121aand the second power supply electrode121b. The first and second power supply electrodes121aand121bmay be spaced apart from each other, and high-frequency power (or RF power) may be supplied (or applied) to each of the first and second power supply electrodes121aand121b.

The ground electrode122may be provided between the first power supply electrode121aand the second power supply electrode121band may be grounded. Here, the ground electrode122may be used as a common ground electrode122for the first and second power supply electrodes121aand121b.

When the high-frequency power source (or high-frequency power) is supplied to the first and second power supply electrodes121aand121b, plasma may be generated between the first power supply electrode121aand the ground electrode122and between the second power supply electrode121band the ground electrode122. That is, the first and second power supply electrodes121aand121band the ground electrode122may have a three-electrode structure, and the high-frequency power may be divided to be supplied to each of the first and second power supply electrodes121aand121b. Thus, the high-frequency power required for generating the plasma or the high-frequency power for obtaining a desired amount of radicals may be reduced, and damage of the first and second power supply electrodes121aand121band the ground electrode122and/or generation of particles due to the high-frequency power may be prevented from occurring.

For example, the plurality of electrodes121and122may be disposed in a discharge space separated from the processing space111by a partition wall125, and a plasma formation part120may be provided by the plurality of electrodes121and122and the partition wall125. The plasma formation part120may generate plasma using the plurality of electrodes121and122and may decompose the process gas supplied from the gas supply tube170by the plasma to provide the decomposed process gas to the processing space111in the reaction tube110. Here, the plasma formation part120may have the discharge space separated from the processing space111by the partition wall125extending in the longitudinal direction of the reaction tube110. Here, the plasma formation part120may extend along the longitudinal direction of the reaction tube110to form plasma in the discharge space by the plurality of electrodes121and122disposed in the circumferential direction of the reaction tube110.

The discharge space of the plasma formation part120may be a space in which the plasma is generated and may be separated from the processing space111by the partition wall125. Thus, the plasma formation part120may decompose the process gas supplied from the gas supply tube170using the plasma in the discharge space and may provide only radicals of the decomposed process gas into the processing space111.

Here, the partition wall125may extend in the longitudinal direction of the reaction tube110, be disposed inside the reaction tube110, or be disposed outside the reaction tube110. For example, the partition wall125may be disposed inside the reaction tube110to define the discharge space together with an inner wall of the reaction tube110as illustrated inFIG.1, and may include a plurality of sub sidewalls connected to the inner wall (or inner surface) of the reaction tube110and a main sidewall between the plurality of sub sidewalls. The plurality of sub sidewalls may protrude (or extend) from the inner wall of the reaction tube110to the inside of the reaction tube110and may be spaced apart from each other to be disposed in parallel. In addition, the main sidewall may be spaced apart from the inner wall of the reaction tube110and disposed between the plurality of sub sidewalls. Here, all the plurality of sub sidewalls and the main sidewall may extend along the inner wall of the reaction tube110in the longitudinal direction of the reaction tube110. However, the partition wall125may be provided in various shapes without being limited to the shape illustrated inFIG.1as long as the partition wall provides the discharge space that is separated from the processing process.

As another embodiment, the partition wall125may be disposed outside the reaction tube110to define the discharge space125together with an outer wall of the reaction tube110and may include the plurality of sub sidewalls connected to an outer surface (or outer wall) of the reaction tube110and the main sidewall between the plurality of sub sidewalls. The plurality of side sidewalls115aand115bmay protrude from the outer wall of the reaction tube110to the outside of the reaction tube110and may be disposed to be spaced apart from each other and parallel to each other. In addition, the main sidewall may be spaced apart from the outer wall of the reaction tube110and disposed between the plurality of sub sidewalls.

The main sidewall may be provided in the form of a tube having a diameter less or greater than that of the reaction tube110to define the discharge space between the sidewall of the reaction tube110and the main sidewall (i.e., between the inner wall of the reaction tube and the main sidewall or between the outer wall of the reaction tube and the main sidewall).

The plasma formation part120may generate the plasma in the discharge space separated from the processing space111by the partition wall125so that the process gas supplied from the gas supply tube170is not directly supplied into the reaction tube110to be decomposed in the processing space111, but is decomposed in the discharge space that is a space separated from the processing space111and then supplied into the processing space111. The inner wall (or an inside wall) of the processing space111as well as the substrate10may increase in temperature by a hot wall type heating unit (or heater) surrounding the processing space111, and thus, the process gas may be deposited to form an undesired thin film on the inner wall of the processing process111. The thin film formed (or deposited) on the inner wall of the processing space111may act as a contaminant during the processing process of the substrate10while being separated as particles by an electric field or a magnetic field caused by the plasma. Thus, when the plasma formation part120generates the plasma in the discharge space that is separated from the processing space111through the partition wall125to directly supply the process gas into the processing space111, thereby generating the plasma in the processing space111, a limitation in which the thin film formed on the inner wall of the processing space111is separated as the particles by the electric field and magnetic field, may be prevented from occurring.

The electrode protection part130may protect the plurality of electrodes121and122and may surround at least a portion of each of the plurality of electrodes121and122to protect each of the plurality of electrodes121and122. For example, the electrode protection part130may surround at least a portion of each of the first and second power supply electrodes121aand121band the ground electrode122to protect the first and second power supply electrodes121aand121band the ground electrode122.

FIG.2is a conceptual view for explaining a flow of a cooling gas of the electrode protection part in accordance with an exemplary embodiment.

Referring toFIG.2, the electrode protection part130may include a plurality of first electrode protection tubes131, which are respectively provided in the first and second power supply electrodes121aand121b, a second electrode protection tube132provided in the ground electrode122, and a plurality of connection tubes133connecting each of the plurality of first electrode protection tubes131to the second electrode protection tube132to communicate with each other. The plurality of first electrode protection tubes131may be provided in the first and second power supply electrodes121aand121b, respectively, and surround an outer circumferential surface of each of the first and second power supply electrodes121aand121bto protect the first and second power supply electrodes121aand121b.

The second electrode protection tube132may be provided in the ground electrode122and may surround an outer circumferential surface of the ground electrode122to protect the ground electrode122.

For example, each of the first and second power supply electrodes121aand121band the ground electrode122may be protected to be surrounded by the first electrode protection tube131and/or the second electrode protection tube132from the top to the bottom, each of the plurality of power supply electrodes121aand121band the ground electrode122may be made of a flexible braided wire.

In general, electrical conduction due to the use of a high-frequency power source may cause a skin effect in which current flows along a surface (or may be affected by a depth of penetration of metal, which is a depth through which current flows). In addition, in the case of using a mesh type electrode for the first and second power supply electrodes121aand121band the ground electrode122, since an area occupied by an empty space is large, and thus, there is a limitation of inefficiency in supplying the high-frequency power by large resistance due to the large surface area. Furthermore, the processing process for the substrate10may be repeatedly performed at high and low temperatures, and when the first and second power supply electrodes121aand121band the ground electrode122are provided in the mesh type, the shape of the mesh electrode may be irregularly changed according to the temperature, which is disadvantageous in terms of maintaining the shape. In addition, there is a limitation in that nonuniform plasma is generated when high-frequency power is supplied because resistance varies in accordance with the changed shape.

In order to prevent these limitations, the first and second power supply electrodes121aand121band the ground electrode122may be not only inserted into the first electrode protection tube131and/or the second electrode protection tube132, but also minimize the empty space, and thus be provided in the braided type (braided wire) having flexibility. For example, in order to further reduce the empty space, a method of applying a metal on the surface of each of the electrodes may be additionally performed. In addition, a spring part (not shown) that fixes and supports both ends of each of the first and second power supply electrodes121aand121band the ground electrode122so as not to move may be further provided so that the flexible braided type first and second power supply electrodes121aand121band the ground electrode122extend in the longitudinal direction of the reaction tube110inside the discharge space and then are maintained in a fixed state. As a result, each of the first and second power supply electrodes121aand121band the ground electrode122, which are flexible, may be fixed in the longitudinal direction of the reaction tube110by the spring part and then maintained in a thin and elongated rod shape.

The first electrode protection tube131and the second electrode protection tube132may surround the outside of the first and second power supply electrodes121aand121band the outside of the ground electrode122, respectively, to electrically insulate each of the first and second power supply electrodes121aand121band the ground electrode122and also protect the first and second power supply electrodes121aand121band the ground electrode122, which are exposed to the plasma atmosphere, from the plasma. In addition, the first and second power supply electrodes121aand121band the ground electrode122may be safely protected from the contamination or particles that may be generated by the plasma. Here, each of the first electrode protection tube131and the second electrode protection tube132may be made of a heat-resistant material such as quartz or ceramic and may be manufactured to be integrated with the reaction tube110.

The plurality of connection tubes133may connect each of the plurality of first electrode protection tubes131to the second electrode protection tube132and may allow the plurality of first electrode protection tubes131and the second electrode protection tube132to communicate with each other. Here, the plurality of connection tubes133may maintain an interval between each of the plurality of first electrode protection tubes131and the second electrode protection tube132. Thus, the interval between the first power supply electrode121aand the ground electrode122and the interval between the first power supply electrode121aand the ground electrode122may be maintained uniformly (or constantly), and also, the interval between each of the first and second power supply electrodes121aand121band the ground electrode122may be uniformly spaced apart from each other.

In order to obtain a uniform plasma density in the discharge space, the spaced space (or plasma generation space) between the first power supply electrode121aand the ground electrode122and the spaced space between the second power supply electrode121band the ground electrode122have to have the same volume (or area). In addition, it is necessary that the plasma (or plasma potential) having the same intensity is generated in the spaced space between the first power supply electrode121aand the ground electrode122and the spaced space between the second power supply electrode121band the ground electrode122to generate a uniform plasma density in the spaced space between the first power supply electrode121aand the ground electrode122and the spaced space between the second power supply electrode121band the ground electrode122. For this, each of the plurality of first electrode protection tubes131may be connected to the second electrode protection tube132to maintain the interval between each of the plurality of first electrode protection tubes131may be connected to the second electrode protection tube132. Thus, the interval between the first power supply electrode121aand the ground electrode122and the interval between the first power supply electrode121aand the ground electrode122may be maintained to be the same. Thus, the interval between the first power supply electrode121aand the ground electrode122and the interval between the first power supply electrode121aand the ground electrode122have the same volume, so that the plasma density is uniform in a plurality of plasma generation spaces (or the spaced spaces).

In addition, the plurality of connection tubes133may connect the plurality of first electrode protection tubes131to the second electrode protection tube132as well as allow the first electrode protection tubes131and the second electrode protection tube132to communicate with each other so that a gas flows between the first electrode protection tubes131and the second electrode protection tube132. For example, a gas passage, in which the inner walls (or inner surfaces) of the plurality of first electrode protection tubes131and the second electrode protection tube132are respectively spaced apart from the first and second power supply electrodes121aand121band the ground electrode122(or from surfaces of the first and second power supply electrodes and the ground electrode) so that a gas flows, may be provided in each of the plurality of first electrode protrusion tubes131and the second electrode protection tube132. In addition, a gas passage having a tube shape may be provided in each of the plurality of connection tubes133to allow the gas passage of each of the plurality of first electrode protection tubes131and the gas passage of the second electrode protection tube131to communicate with each other.

Here, the plurality of electrodes121and122may generate capacitively coupled plasma (CCP) in the spaced space between the first power supply electrode121aand the ground electrode122and the spaced space between the second power supply electrode121band the ground electrode122. The first and second power supply electrodes121aand121bmay be spaced apart from the ground electrode122to define the plurality of plasma generation spaces. That is, the spaced space between the first power supply electrode121aand the ground electrode122and the spaced space between the second power supply electrode121band the ground electrode122may provide the plurality of plasma generation spaces.

In addition, the plurality of electrodes121and122may generate the capacitively coupled plasma (CCP) in the spaced space (plasma generation space) between the first power supply electrode121aand the ground electrode122and the spaced space (plasma generation space) between the second power supply electrode121band the ground electrode122. For example, as the high-frequency power is supplied to each of the first and second power supply electrodes121aand121b, the capacitively coupled plasma (CCP) may be generated by an electric field generated in the spaced space between the first power supply electrode121aand the ground electrode122and the spaced space between the second power supply electrode121band the ground electrode122.

Unlike the capacitively coupled plasma (CCP) method in which energy is obtained through electron acceleration generated by the electric field generated in the spaced space between the first power supply electrode121aand the ground electrode122and the spaced space between the second power supply electrode121band the ground electrode122to generate the plasma, in the inductively coupled plasma (ICP) method, when a magnetic field generated by current flowing through antennas connected to each other is changed over time, plasma may be generated from the electric field generated around the magnetic field. In general, in the inductively coupled plasma (ICP) method, the plasma is generated by E-mode and converted to H-mode to generate high-density plasma. The inductively coupled plasma (ICP) method is divided into the E-mode and the H-mode according to plasma density or applied power. In order to perform the mode conversion from the E-mode with low plasma density to the H-mode with high plasma density, high power has to be induced. Here, when input power increases, a number of radicals that do not participate in the reaction in accordance with particles and a high electron temperature are generated to cause limitations, in which it difficult to obtain a good quality film, and it is difficult to generate uniform plasma in accordance with the electric fields generated by the antenna.

However, in the present disclosure, since the capacitively coupled plasma (CCP) is generated in each of the paced space between the first power supply electrode121aand the ground electrode122and the spaced space between the second power supply electrode121band the ground electrode122, it is unnecessary to induce high power for performing the mode conversion as in the inductively coupled plasma (ICP). As a result, it is more effective in preventing the generation of the particles and obtaining the good quality film by generating a large number of radicals participating in the reaction in accordance with the low electron temperature.

The batch type substrate processing apparatus100in accordance with an exemplary embodiment may further include a cooling gas supply part150that supplies a cooling gas into the plurality of first electrode protection tubes131and the second electrode protection tube132, and a cooling gas discharge part160that discharges the cooling gas from the plurality of first electrode protection tubes131and the second electrode protection tube132to generate a flow of the cooling gas.

The cooling gas supply part150may supply the cooling gas to the plurality of first electrode protection tubes131and the second electrode protection tube132to cool the first and second power supply electrodes121aand121band the ground electrode122, which are disposed in the plurality of first electrode protection tubes131and the second electrode protection tube132, respectively. Heat may be generated while the plasma is generated by supplying the high-frequency power to the first and second power supply electrodes121aand121b. Due to the increase in temperature of the first and second power supply electrodes121aand121band the ground electrode122by the heat generation, (metal) resistance of the first and second power supply electrodes121aand121band the ground electrode122may increase, and thus, a (induced) voltage may increase by the following formula: voltage (V)=current (I)×resistance (R) to increase in energy of ions generated by the plasma. In addition, the ions having high energy may strongly collide with the surfaces of the plurality of first electrode protection tubes131and/or the second electrode protection tube132to cause damage of the plurality of first electrode protection tubes131and the second electrode protection tube132and/or generate particles such as metal components contained in a material that forms the first electrode protection tube131and the second electrode protection tube132, such as quartz. The Particles generated as described above may act as contaminants in the reaction tube110to cause (metal) contamination of the thin film. For example, the contaminant particles (or particles) generated during a process of manufacturing a semiconductor device are very closely related to yield of the device, and in particular, the (metal) contamination particles generated during the thin film process conduct current to cause current leakage. Due to the current leakage, a malfunction of the device may be caused, and a fatal adverse effect may be exerted on the yield of the product.

Therefore, in the present disclosure, the cooling gas may be supplied into the plurality of first electrode protection tubes131and the second electrode protection tube132through the cooling gas supply part150to cool the first and second power supply electrodes121aand121band the ground electrode122, thereby preventing or suppressing the increase in temperature of each of the first and second power supply electrodes121aand121band the ground electrode122. Thus, the energy of the ions generated by the plasma may be prevented from increasing, and the plurality of first electrode protection tubes131and/or the second electrode protection tubes132may be prevented from colliding with each other on the surfaces of the plurality of electrode protrusion tubes131and/or the second electrode protection tube132due to the high level energy of the ions to exclude the effect of the (metal) contamination.

In addition, the process of processing the substrate10may be performed at a high temperature of approximately 600° C. or more, and the first and second power supply electrodes121aand121band the ground electrode122made of a metal such as nickel (Ni) may be oxidized at a high temperature of approximately 600° C. or more. Thus, the cooling gas may be supplied as a protective gas into the plurality of first electrode protection tubes131and the second electrode protection tube132through the cooling gas supply part150to prevent the first and second power supply electrodes121aand121band the ground electrode122from being oxidized. In addition, a lifespan of each of the first and second power supply electrodes121aand121band the ground electrode122may be improved.

For example, the cooling gas may be supplied to the plurality of first electrode protection tubes131or second electrode protection tubes132and also flow into the other electrode protection tube131or132via the connection tube133(or through the connection tube). Here, the cooling gas supply part150may include a flowmeter151that measures a flow rate (or supply amount) of the cooling gas. Thus, the flow rate of the cooling gas may be measured through the flowmeter151to adjust the supply amount (or flow rate) of the cooling gas.

The cooling gas discharge part160may discharge the cooling gas from the plurality of first electrode protection tubes131and the second electrode protection tube132to generate a flow of the cooling gas. For example, the cooling gas supply part150may be connected to the plurality of first electrode protection tubes131or the second electrode protection tube132. In addition, the cooling gas discharge part160may be connected to the remaining electrode protection tube131or132, to which the cooling gas supply part150is not connected, among the plurality of first electrode protection tubes131and the second electrode protection tube132to discharge the cooling gas supplied to the first electrode protection tubes131or the second electrode protection tube132. As a result, the cooling gas supplied to the plurality of first electrode protection tubes131or the second electrode protection tube132to flow to the remaining electrode protection tube131or132through the connection tube133may be discharged.

In the present disclosure, a passage of the cooling gas, which passes through the plurality of first electrode protection tubes131or the second electrode protection tubes132, the connection tube133, and the remaining electrode protrusion tube131or132may be provided through the cooling gas supply part150, the connection tube133, and the cooling gas discharge part160. Thus, the cooling gas may effectively flow through the plurality of first electrode protection tubes131and the second electrode protection tube132to effectively cool the first and second power supply electrodes121aand121band the ground electrode122and effectively prevent the first and second power supply electrodes121aand121band the ground electrode122from being oxidized.

Here, the plurality of connection tubes133may connect one end (e.g., upper end) of each of the first electrode protection tubes131to one end of the second electrode protection tube132.

FIG.3is a conceptual view for explaining voltage waveforms and electric fields of the first and second power supply electrodes and the ground electrode in accordance with an exemplary embodiment. Here, (a) ofFIG.3illustrates voltage waveforms of the first and second power supply electrodes and the ground electrode, and (b) ofFIG.3illustrates electric fields of the first and second power supply electrodes and the ground electrode.

Referring toFIG.3, voltages applied to the first and second power supply electrodes121aand121bmay be synthesized (or merged) to induce a high induced voltage (e.g., twice the voltage) to the ground electrode122, and also, high-temperature heat, which is higher than that of the first and second power supply electrodes121aand121b) may be generated due to overlapping of electric fields. That is, the common ground electrode122may be affected by both the first power supply electrode121aand the second power supply electrode so that the electric fields overlap each other, and as a result, the high-temperature heat may be generated in the ground electrode122.

In detail, in the three-electrode structure using the common ground electrode122, the voltage applied to the first power supply electrode121aand the voltage applied to the second power supply electrode121bhave the same phase difference, and thus, electric fields greater than those of the first and second power supply electrodes121aand122bmay be induced to the ground electrode122. Thus, due to the undesired the high electric field, the plasma potential increases in proportion to the electric field. When the plasma potential of the ground electrode122increases in this manner, the high-temperature heat of the ground electrode122may be generated to case plasma damage. In addition, the plasma damage may occur to cause damage in the second electrode protrusion tube132around the ground electrode122, the partition wall125, and the reaction tube110as well as the ground electrode122to which the double voltage is induced.

Thus, effective cooling of the ground electrode122, which generates the high-temperature heat, is required.

For the effective cooling of the ground electrode122, the cooling gas supply part150may be connected to the second electrode protection tube132, and the cooling gas discharge part160may be connected to the plurality of first electrode protection tubes131. The cooling gas supply part150may be connected to the second electrode protection tube132to first supply the cold cooling gas to the second electrode protection tube132in which the ground electrode122is disposed (or inserted), thereby effectively cooling the ground electrode122in which the high-temperature heat is generated to the cooling gas that is in a cold state because of passing through the other electrode protection tube (i.e., the first electrode protrusion tube). That is, the cooling gas may be in contact with the ground electrode122in which the high-temperature heat is generated in the cold state to cause a large temperature difference between the cooling gas and the ground electrode122so that heat-exchange is actively performed between the cooling gas and the ground electrode122. Thus, the ground electrode122that generates the high-temperature heat may be effectively cooled.

On the other hand, when the cooling gas supply part150is connected to at least one of the plurality of first electrode protection tubes131to supply the cooling gas from at least one of the plurality of first electrode protection tubes131, the cooling gas may be heat-exchanged with the first power supply electrode121aand the second power supply electrode121bwhile passing through at least one of the plurality of first electrode protrusion tubes131. As a result, a temperature difference between the heated cooling gas and the ground electrode122becomes insignificant (or reduced), and the cooling of the ground electrode122that generates the high-temperature heat may be insignificant (or ineffective).

The cooling gas discharge part160may be connected to each of the plurality of first electrode protection tubes131. Thus, the cooling gas supplied to the second electrode protection tube132to cool the ground electrode122may be moved (or introduced) to each of the first electrode protection tubes131through the (plurality of) connection tubes133, and after cooling the first power supply electrode121aand the second power supply electrode121bwith the cooling gas introduced into the plurality of first electrode protection tubes131, the cooling gas may be discharged. Thus, a flow of the cooling gas, in which the cooling gas is supplied to the second electrode protection tube132through the cooling gas supply part150to pass through each of the connection tubes133and then pass through each of the first electrode protection tubes131, and then may be discharged to the cooling gas discharge part160, may occur. In addition, two flows of the cooling gas branched (or distributed) from the second electrode protection tube132to the first electrode protection tubes131disposed at both sides based on the second electrode protection tube132may be generated.

Here, the cooling gas supplied to the second electrode protection tube132may be distributed to move to the plurality of first electrode protection tubes131through the plurality of connection tubes133after cooling the ground electrode122that generates the high-temperature heat. Therefore, even if heated by the heat-exchange with the ground electrode122, the cooling gas may have a temperature less than that of each of the first and second power supply electrodes121aand121b, and thus, the first and second power supply electrodes121aand121bmay be cooled. Here, heat (having a temperature less than that of the ground electrode122) may be generated in the first and second power supply electrodes121aand121b, and as a result, even the cooling gas heated by the heat-exchange with the ground electrode122may also sufficient cool the first and second power supply electrodes121aand121b.

When the cooling gas is supplied to the second electrode protection tube132and then distributed to the plurality of first electrode protection tubes131through the plurality of connection tubes133to generate the two flows of the cooling gas, the two flows of the cooling gas may be smooth without interfering with each other. On the other hand, when the cooling gas is supplied to the plurality of first electrode protection tubes131, and then, the cooling gas is discharged to the second electrode protection tube132, the cooling gas supplied to the plurality of first electrode protection tubes131may be joined (or merged) into one second electrode protection tube132through the plurality of connection tubes133to cause a bottleneck and/or a vortex. As a result, the flow of the cooling gas is not smooth, and the cooling of the first and second power supply electrodes121aand121band/or the ground electrode122may not be effective. That is, since the cooling gas is merged from the plurality of first electrode protection tubes131into one second electrode protection tube132, the two flows of the cooling gas may interfere with each other, and thus, the flow of the cooling gas may not smooth.

Here, the cooling gas discharge part160may include exhaust lines161respectively connected to the plurality of first electrode protection tubes131. The exhaust line161may be connected to each of the plurality of first electrode protection tubes131. Thus, the cooling gas may be supplied to the second electrode protection tube132to cool the ground electrode122and be distributed to the plurality of first electrode protection tubes131through the plurality of connection tubes133to move so that the cooling gas cools the first power supply electrode121aor the second power supply electrode121band then is discharged. Here, the exhaust line161may be connected to each of the plurality of first electrode protection tubes131, and thus, an amount of cooling gas at a position (e.g., an exhaust port) is greater than that at a position (e.g., an inlet), i.e., the exhaust port is widened than the inlet so that the cooling gas is smoothly discharged. In addition, the flow of the cooling gas may be made smooth in accordance with the supply of the cooling gas.

In addition, the exhaust line161may include a first exhaust line161aconnected to a pumping port, and a second exhaust line161bbranched with the first exhaust line161a. The first exhaust line161amay be connected to the pumping port to generate an exhaust pressure (or a pressure for the exhaust) in at least a portion (e.g., the first exhaust line) of the exhaust line161, and thus, the cooling gas may be smoothly discharged from the plurality of first electrode protection tubes131.

For example, the first exhaust line161amay be connected to a vacuum pump165connected to the pumping port to quickly discharge the cooling gas that is heated by the heat-exchange with the ground electrode122and the first power supply electrode121aor the second power supply electrode121b. As a result, the ground electrode122and the first and second power supply electrodes121aand121bmay be rapidly cooled to improve cooling efficiency of the ground electrode122and the first and second power supply electrodes121aand121b.

The second exhaust line161bmay be branched with the first exhaust line161ato exhaust the cooling gas to the atmosphere without generating an artificial exhaust pressure through the vacuum pump165or the like.

Here, a flow rate of the cooling gas in each of the first electrode protection tubes131may be less than the flow rate of the cooling gas in the second electrode protection tube132, and thus, the cooling gas may be effectively discharged even when the cooling gas is discharged at the same time from the plurality of first electrode protection tubes131through one vacuum pump165. In addition, since an internal pressure of each of the first electrode protection tubes131is less than that of the second electrode protection tube132, the cooling gas may effectively flow from the second electrode protection tube132to each of the first electrode protection tubes131.

Here, the cooling gas discharge part160may further include a diameter adjusting member163for adjusting an inner diameter of the exhaust line161. The diameter adjusting member163may adjust an inner diameter of the exhaust line161and may adjust an inner diameter of at least the first exhaust line161a. Since each of the plurality of first electrode protection tubes131and the second electrode protection tube132is made of quartz or the like and thus broken by a vacuum pressure (or negative pressure), the inside of each of the plurality of first electrode protection tubes131and the second electrode protection tube132may be maintained at an appropriate (internal) pressure (e.g., atmospheric pressure level). When the exhaust pressure is generated in the exhaust line161through the vacuum pump165without the diameter adjusting member163, a too low (internal) pressure (or vacuum pressure) may be generated in the plurality of first electrode protection tubes131and the second electrode protection tube132, and thus, the plurality of first electrode protection tubes131and/or the second electrode protection tubes132may be broken. Thus, even if the inner diameter of at least the first exhaust line161aof the exhaust lines161is reduced (or adjusted) through the diameter adjusting member163to generate the exhaust pressure in the exhaust line161through the vacuum pump165, the inside of the first electrode protection tube131and the second electrode protrusion tube132may be maintained at an appropriate (internal) pressure.

For example, the diameter adjusting member163may include an orifice, and the orifice may be inserted by the ¼ inch into the first exhaust line161aso that the cooling gas that cools the ground electrode122and the first power supply electrode121aor the second power supply tube121bis constantly discharged to the vacuum pump165. Here, the orifice may be provided as a punched thin plate and may be used for the purpose of pressure drop and flow restriction to help the discharge of the cooling gas at a stable exhaust pressure.

The batch type substrate processing apparatus100in accordance with the present disclosure may further include a needle valve164installed in the exhaust line161to adjust a discharge amount of cooling gas that cools the ground electrode122and the first power supply electrode121aor the second power supply tube121b. The needle valve164may be installed in the exhaust line161to finely adjust the flow rate. Here, the needle valve164may manually control an ultra-fine flow rate, and thus, the exhaust amount may be adjusted for vacuum exhaust and/or air exhaust (or heat exhaust).

Here, the cooling gas discharge part160may further include a first valve162aprovided in the first exhaust line161a, and a second valve162bprovided in the second exhaust line161b. The first valve162amay be provided in the first exhaust line161a, and when the first valve162ais opened, the exhaust through the first exhaust line161amay be performed, and thus, the vacuum exhaust may be performed.

The second valve162bmay be provided in the second exhaust line161b, and when the second valve162bis opened, the exhaust through the second exhaust line161bmay be performed, and thus, the atmospheric exhaust may be performed.

For example, the first valve162aand the second valve162bmay be provided (or installed) behind (or at a rear end) of a joining point161cbetween the exhaust line161connected to the first electrode protection tube131, in which the first power supply electrode121ais disposed, and the exhaust line161connected to the first electrode protrusion tube131, in which the second power supply electrode12bis disposed. Here, the vacuum exhaust and the atmospheric exhaust may be diverged at the joining point161cin accordance with the opening and closing of each of the first valve162aand the second valve162b.

Here, the first valve162amay be opened when the power is supplied to the first and second power supply electrodes121aand121b, and the second valve162bmay be opened when the power is not supplied to the first and second power supply electrodes121aand121b. That is, when (high-frequency) power is supplied to the first and second power supply electrodes121aand121bto generate the plasma, the first and second power supply electrodes121aand121band the ground electrode122may generate heat. Thus, the first valve162amay be opened to rapidly cool the ground electrode122and the first and second power supply electrodes121aand121bthrough the generation of the exhaust pressure of the exhaust line161, thereby improving the cooling efficiency of the ground electrode122and the first and second power supply electrodes121aand121b. In addition, when the power is not supplied to the first and second power supply electrodes121aand121bbecause the plasma generation is not required, the second valve162bmay be opened to exhaust the cooling gas, which is heated by the heat-exchange with the ground electrode122and the first power supply electrode121aor the second power supply tube121b, to the atmosphere. Here, when the first valve162ais opened, the second valve162bmay be closed, and when the second valve162bis opened, the first valve162amay be closed.

The exhaust line161may generate an exhaust pressure of approximately 0.15 mbar or more per standard liter per minute (slm) of a flow rate of the cooling gas, and specifically, an exhaust pressure of approximately 0.15 to approximately 20 mbar or more per 1 slm of a flow rate of the cooling gas. When the cooling gas is supplied to (only) the second electrode protection tube132, the cooling gas has to be uniformly distributed to flow through the plurality of first electrode protection tubes131, and the cooling efficiency of the first and second power supply electrodes121aand121bhas to be maintained at the same level. However, due to a sagging (or tilting) phenomenon of the ground electrode122, the first power supply electrode121aor the second power supply electrode121b, an interval between each electrode121or122and the electrode protrusion tube131or132may be non-uniform to disturb the flow of the cooling gas. This may act as a factor in deteriorating the cooling efficiency of the first and second power supply electrodes121aand121band/or the ground electrode122.

Thus, the exhaust line161may generate an exhaust pressure of approximately 0.15 mbar or more per 1 slm of a flow rate of the cooling gas. In this case, the sagging phenomenon of the ground electrode122, the first power supply electrode121aor the second power supply electrode121bmay be suppressed or prevented to maintain the interval between each electrode121or122and the electrode protrusion tube131or132at the same level, and also, even if the interval between each electrode121or122and the electrode protection tube131or132is not constant, the cooling gas may be uniformly distributed to flow to the plurality of first electrode protrusion tubes131. In addition, since the cooling gas at a (almost) constant (or the same level) flow rate may flow through the plurality of first electrode protection tubes131, the cooling efficiency of the first and second power supply electrodes121aand121bmay be equalized.

Here, when an exhaust pressure exceeding approximately 20 mbar per 1 slm of a flow rate of the cooling gas is generated in the exhaust line161, the cooling gas may flow too fast, and thus, the cooling gas may not be sufficiently heat-exchanged with the ground electrode122, the first power supply electrode121aand/or the second power supply electrode121b, and rather, the cooling efficiency of the first and second power supply electrodes121aand121band the ground electrode122may be deteriorated.

The exhaust pressure of each of the exhaust line161connected to the first electrode protrusion tube131, in which the first power supply electrode121ais disposed, and the exhaust line161connected to the first electrode protrusion tube131, in which the second power supply electrode121bmay be adjusted (controlled).

The exhaust pressure of each of the exhaust line161connected to the first electrode protrusion tube131, in which the first power supply electrode121ais disposed, and the exhaust line161connected to the first electrode protrusion tube131, in which the second power supply electrode121bmay be adjusted, and thus, the cooling gas having a (almost) constant flow rate may flow through the plurality of first electrode protection tube131. Here, a flow rate of each of the plurality of first electrode protection tubes131may be measured to adjust the exhaust pressure of each of the exhaust line161connected to the first electrode protrusion tube131, in which the first power supply electrode121ais disposed, and the exhaust line161connected to the first electrode protrusion tube131, in which the second power supply electrode121b. In addition, the exhaust pressure of each of the exhaust line161connected to the first electrode protrusion tube131, in which the first power supply electrode121ais disposed, and the exhaust line161connected to the first electrode protrusion tube131, in which the second power supply electrode121bmay be adjusted so that the flow rate of each of the plurality of first electrode protection tubes131varies for appropriate cooling in accordance with the temperature of each of the first and second power supply electrodes121aand121b.

Each of the plurality of connection tubes133may have an inner diameter less than that of each of the plurality of first electrode protection tubes131and the second electrode protection tube132. When the plurality of connection tubes133have the inner diameter less than that of each of the plurality of first electrode protection tubes131and the second electrode protection tube132, after the cooling gas is sufficiently filled in the second electrode protection tube132, the cooling gas may be distributed into the plurality of first electrode protection tubes131. Also, since the inside of the second electrode protection tube132is sufficiently filled with the cooling gas, the oxidation of the ground electrode122may be effectively prevented.

On the other hand, when the plurality of connection tubes133have an inner diameter equal to or greater than that of each of the plurality of first electrode protection tubes131and the second electrode protection tube132, before the cooling gas supplied into the second electrode protection tube132is (sufficiently) filled in the second electrode protrusion tube132, the cooling gas may flow out into the plurality of connection tubes133. Due to this structure, the cooling gas may not be supplied to the entire surface of the ground electrode122, the first power supply electrode121aand/or the second power supply electrode121b, and thus, the oxidation prevention effect may be reduced. In addition, the cooling efficiency may be deteriorated because there is a portion at which the heat-exchange is not performed, and temperature non-uniformity may occur at each position in the ground electrode122, the first power supply electrode121aand/or the second power supply electrode121b, and thus, the ground electrode122, the first power supply electrode121aand/or the second power supply electrode121bmay be damaged, or the plasma discharge (or generation) performance may be affected.

Therefore, in the present disclosure, these limitations may be solved by making the inner diameter of each of the plurality of connector tubes133, which is less than the inner diameter of each of the plurality of first electrode protection tubes131and the second electrode protection tubes132.

Here, the cooling gas may include an inert gas, and the inert gas may be nitrogen (N2), argon (Ar), or the like. The inert gas such as nitrogen (N2) may be supplied into the plurality of first electrode protection tubes131and the second electrode protection tube132to prevent oxygen (O2) from being introduced into or staying in the plurality of first electrode protection tubes131and the second electrode protection tube132. As a result, it is possible to prevent the first and second power supply electrodes121aand121band the ground electrode122from being oxidized by reacting with oxygen (O2).

When the power is not supplied to the first and second power supply electrodes121aand121b, the cooling gas supply part150may supply the cooling gas, which has a flow rate less than that when the power is supplied to the first and second power supply electrodes121aand121b. The first and second power supply electrodes121aand121band the ground electrode122may generate the heat only when the plasma is generated by supplying the power to the first and second power supply electrodes121aand121b. For this reason, when the power is not supplied to the first and second power supply electrodes121aand121bbecause the plasma is not generated (or discharged), the cooling gas having a flow rate (e.g., approximately 3 slm) less than that (e.g., approximately 10 slm) when the power is supplied to the first and second power supply electrodes121aand121bmay be supplied and also be discharged through the general atmospheric exhaust to save energy consumption.

The batch type substrate processing apparatus100in accordance with an embodiment may further include a plurality of first sealing caps141respectively connected to the first electrode protection tubes131and provided with an exhaust port141a, through which the cooling gas is discharged, on the sidewall of the inner spaces communicating with the first electrode protection tubes131, and a second sealing cap142connected to the second electrode protection tube132and provided with an inlet142a, through which the cooling gas is supplied, on a sidewall of the inner space communicating with the second electrode protection tube132.

The plurality of first sealing caps141may be respectively connected to the plurality of first electrode protection tubes131and may have an inner space communicating with each of the first electrode protection tubes131so that at least a portion of the first power supply electrode121aor the second power supply electrode121bis inserted (or accommodated). In addition, the plurality of first sealing caps141may be provided with the exhaust port141a, through which the cooling gas is discharged in a radial direction, on the sidewall of the inner space communicating with each of the first electrode protection tubes131. That is, the exhaust port141amay be provided in a direction perpendicular to an extension direction of the first power supply electrode121aor the second power supply electrode121b.

For example, the plurality of first sealing caps141may be connected to the other ends (e.g., lower ends) of the plurality of first electrode protection tubes131, respectively, and a first sealing member135such as an O-ring may be disposed between each of the first electrode protection tubes131and the first sealing cap141. In addition, rear ends (or lower ends) of the first power supply electrode121aand the second power supply electrode121bmay be drawn out through each of the first sealing caps141. Here, each of the first power supply electrode121aand the second power supply electrode121bmay be provided with a protrusion having a width wider than that of each of other portions accommodated in the inner space of the first sealing cap141, and the protrusion may be hooked with a stepped portion of the rear end (e.g., the lower end) of each of the first sealing cap141. Here, the protrusion may be provided so that each of the first power supply electrode121aand the second power supply electrode121bprotrude itself or may be provided by adding the same material or another material to the first power supply electrode121aand the second power supply electrode121b. Here, a second sealing member145such as an O-ring may be disposed between the protrusion of the first power supply electrode121aor the second power supply electrode121band the stepped portion of the rear end of each of the first sealing caps141. Thus, the first power supply electrode121aand the second power supply electrode121bmay be stably supported to prevent or suppress the sagging of the first power supply electrode121aand the second power supply electrode121bfrom occurring, and the other end of each of the first electrode protection tubes131may be sealed.

The second sealing cap142may be connected to the second electrode protection tube132and may have an inner space communicating with the second electrode protection tube132so that at least a portion of the ground electrode122is inserted. In addition, the second sealing cap142may be provided with the inlet142a, through which the cooling gas is supplied in the radial direction, on the sidewall of the inner space communicating with the second electrode protection tube132. That is, the inlet142amay be provided in a direction perpendicular to the extension direction of the ground electrode122.

For example, the second sealing cap142may be connected to the other end of the second electrode protection tube132, and the first sealing member135may be disposed between the second electrode protection tube132and the second sealing cap142. In addition, the rear end of the ground electrode122may be drawn out through the second sealing cap142, and the ground electrode122may be provided with a protrusion having a width wider than that of each of other portions accommodated in the inner space of the second sealing cap142and thus be hooked with the stepped portion of the rear end of the second sealing cap142. Here, the protrusion may be provided so that the ground electrode122itself protrudes or may be provided by adding the same material or another material to the ground electrode122. Here, the second sealing member145may be disposed between the protrusion of the ground electrode122and the stepped portion at the rear end of the second sealing cap142. Thus, the ground electrode122may be stably supported to prevent or suppress the sagging of the ground electrode122, and the other end of the second electrode protection tube132may be sealed.

Since the cooling gas is supplied toward the side surface of the ground electrode122through the inlet142aprovided in the direction perpendicular to the extension direction of the ground electrode122, the cooling gas may be quickly and effectively diffused along the side surface of the ground electrode122. In addition, since the cooling gas flows to be in contact with the surface of the ground electrode122, the heat-exchange between the ground electrode122and the cooling gas may be effectively performed. In addition, since the cooling gas flows quickly and effectively along the side surface of the first power supply electrode121aor the second power supply electrode121bthrough the exhaust port141aprovided in the direction perpendicular to the extension direction of the first power supply electrode121aor the second power supply electrode121b, the cooling gas may flow to be in contact with the surface of the first power supply electrode121aor the second power supply electrode121bso that the heat-exchange between the first power supply electrode121aor the second power supply electrode121band the cooling gas is effectively performed.

In addition, the inlet142aof the second sealing cap142and the exhaust port141aof the first sealing cap141may have different sizes (or diameters) and/or numbers. For example, two inlets142athat is more than the number of the exhaust ports141aof the first sealing cap141may be provided in the second sealing cap142to supply a large amount of cooling gas to the second electrode protection tube132so that a sufficient amount of cooling gas is supplied by distributing the cooling gas into the plurality of first electrode protrusion tubes while effectively cooling the ground electrode122. In addition, the exhaust port141aof the first sealing cap141may have a size greater than that of the inlet port142aof the second sealing cap142so that the cooling gas is effectively discharged through the exhaust port141aof the first sealing cap141.

The batch type substrate processing apparatus100in accordance with an exemplary embodiment may further include a gas supply tube170that supplies the process gas required for a process of processing a plurality of substrates10, and an exhaust part180that exhausts the inside of the reaction tube110.

The gas supply tube170may supply the process gas that is necessary for the process of processing the plurality of substrates10and may supply the process gas into the reaction tube110through the plasma formation part120. In addition, the gas supply tube170may include a discharge port171that discharges (or injects) the process gas into the discharge space. Here, the plasma forming part120may be arranged in the longitudinal direction of the reaction tube110and include a plurality of injection holes125athrough which the radicals of the process gas decomposed by the plasma are supplied to the processing space111. For example, the plurality of injection holes125amay be defined in the partition wall125and may supply radicals to the processing space111.

Here, the plurality of gas supply tubes170may be arranged to be symmetrical to each other about a (virtual) line extending from a center of the reaction tube110toward the ground electrode122. As a result, the process gas may be uniformly supplied to the spaced space between the first power supply electrode121aand the ground electrode122and the spaced space between the second power10supply electrode121band the ground electrode122.

The exhaust part180may exhaust the inside of the reaction tube110and may be disposed to face the plasma formation part120. The exhaust part180may be disposed in the processing space111to discharge the process residues in the processing space111to the outside. The exhaust part180may include an exhaust nozzle extending in the longitudinal direction (or vertical direction) of the reaction tube110, an exhaust line connected to the exhaust nozzle, and an exhaust pump. The exhaust nozzle may face the injection hole125aof the plasma formation part130and may include a plurality of exhaust holes arranged in the vertical direction corresponding to the unit processing spaces of the substrate boat.

Thus, the injection hole125aof the plasma formation part120and the exhaust hole of the exhaust part180may correspond to each other and be disposed in the same line in the direction parallel to the surface of the substrate10, which crosses the longitudinal direction of the reaction tube110on which the substrate10is loaded, and thus, the radicals injected from the injection hole125amay be introduced into the exhaust hole to generate a laminar flow. Thus, the radicals injected from the injection holes125amay be uniformly supplied to a top surface of the substrate10

Here, the process gas may include one or more types of gases and may include a source gas and a reaction gas that reacts with the source gas to form a thin film material. For example, when the thin film material to be deposited on the substrate10is silicon nitride, the source gas may include a silicon-containing gas such as dichlorosilane (SiH2Cl2, abbreviation: DCS), and the reaction gas may include a nitrogen-containing gas such as NH3, N2O, No, and the like.

The batch type substrate processing apparatus100in accordance with an exemplary embodiment may further include a heating unit surrounding the reaction tube110to heat the plurality of substrates10. In addition, the substrate boat may rotate by a rotating unit connected to a lower portion of the substrate boat for uniformity of the processing process.

In addition, the RF power may be supplied with RF power in a pulse form. The pulsed RF power may be adjusted in pulse width and duty ratio in a pulse frequency band of approximately 1 kHz to approximately 10 kHz. The duty ratio means a ratio of an on-cycle and an off-cycle. When the pulsed RF power is applied to the first and second power supply electrodes121aand121b, the plasma may be periodically turned on/off, i.e., the plasma may be generated in the form of a pulse. Thus, the density of the ions that damage the plurality of electrodes121and122and the partition wall125and generate the particles during the processing process may be reduced, whereas the density of the radicals may be constantly maintained. Thus, while maintaining efficiency of the processing process, the damage of the plurality of electrodes121and122and the partition wall125due to the plasma may be reduced or prevented from occurring.

As described above, in the exemplary embodiment, the plurality of electrodes exposed to the plasma atmosphere may be protected from the plasma while electrically insulating the plurality of electrodes through the electrode protection part, and the plurality of electrodes may be safely protected from the contamination or particles that may be generated by the plasma. In addition, the plurality of first electrode protection tubes may be respectively connected to the second electrode protection tubes through the plurality of connection tubes to constitute the electrode protection part, and thus, the interval between the first electrode protection tube and the second electrode protection tube may be maintained so that the interval between the first and second power supply electrodes and the ground electrode are uniformly maintained. Therefore, the spaced space between the first power supply electrode and the ground electrode and the spaced space between the second power supply electrode and the ground electrode may have the same volume so that the plasma density between the plurality of plasma generation spaces are uniform. In addition, each of the first electrode protection tubes may communicate with the second electrode protection tube through the plurality of connection tubes to generate the flow of the cooling gas through the cooling gas supply part and the cooling gas discharge part while supplying the cooling gas into the plurality of first electrode protection tubes and the second electrode protection tube. Therefore, the first and second power supply electrodes, which generates the heat while generating the plasma, and the ground electrode may be effectively cooled. Here, the cooling gas may be supplied to the second electrode protection tube provided in the ground electrode, which is affected by all the first power supply electrode and the second power supply electrode to generate the high-temperature heat due to the overlapping of the electric fields, to effectively cool the high-temperature heat of the ground electrode. In addition, since the large amount of cooling gas supplied to the second electrode protection tube is divided into the plurality of first electrode protection tubes and then is discharged, the flow of the cooling gas may be smooth. Here, the exhaust lines respectively connected to the plurality of first electrode protection tubes may be connected to the pumping port to quickly discharge the cooling gas, which is heated due to the heat-exchange with the ground electrode, the first power supply electrode and/or the second power supply electrode, thereby realizing the more effective cooling. Since the exhaust pressure of approximately 0.15 mbar or more per approximately 1 slm flow rate of the cooling gas is generated in the exhaust line, the first power supply electrode and/or the second power supply electrode may be inclined to uniformly supply the cooling gas to the plurality of first electrode protection tubes even when the interval from the first electrode protection tube is not uniform.

The batch type substrate processing apparatus in accordance with the exemplary embodiment may electrically insulate the plurality of electrodes and simultaneously protect the plurality of electrodes, which are exposed to the plasma atmosphere, from the plasma through the electrode protection part and also safely protect the plurality of electrodes from the contamination or particles, which may occur by the plasma. In addition, the plurality of first electrode protection tubes may be respectively connected to the second electrode protection tubes through the plurality of connection tubes to constitute the electrode protection part, and thus, the interval between the first electrode protection tube and the second electrode protection tube may be maintained so that the interval between the first and second power supply electrodes and the ground electrode are uniformly maintained. Therefore, the spaced space between the first power supply electrode and the ground electrode and the spaced space between the second power supply electrode and the ground electrode may have the same volume so that the plasma density between the plurality of plasma generation spaces are uniform.

In addition, each of the first electrode protection tubes may communicate with the second electrode protection tube through the plurality of connection tubes to generate the flow of the cooling gas through the cooling gas supply part and the cooling gas discharge part while supplying the cooling gas into the plurality of first electrode protection tubes and the second electrode protection tube. Therefore, the first and second power supply electrodes, which generates the heat while generating the plasma, and the ground electrode may be effectively cooled.

Here, the cooling gas may be supplied to the second electrode protection tube provided in the ground electrode, which is affected by all the first power supply electrode and the second power supply electrode to generate the high-temperature heat due to the overlapping of the electric fields, to effectively cool the high-temperature heat of the ground electrode. In addition, since the large amount of cooling gas supplied to the second electrode protection tube is divided into the plurality of first electrode protection tubes and then is discharged, the flow of the cooling gas may be smooth.

Here, the exhaust lines respectively connected to the plurality of first electrode protection tubes may be connected to the pumping port to quickly discharge the cooling gas, which is heated due to the heat-exchange with the ground electrode, the first power supply electrode and/or the second power supply electrode, thereby realizing the more effective cooling.

Since the exhaust pressure of approximately 0.15 mbar or more per approximately 1 slm flow rate of the cooling gas is generated in the exhaust line, the first power supply electrode and/or the second power supply electrode may be inclined to uniformly supply the cooling gas to the plurality of first electrode protection tubes even when the interval from the first electrode protection tube is not uniform.

Although embodiments have been described with reference to a number of illustrative embodiments thereof, the embodiments are not limited to the foregoing embodiments, and thus, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. Hence, the real protective scope of the present invention shall be determined by the technical scope of the accompanying claims.