Exhaust piping device

Abstract

PURPOSE: To provide an exhaust piping device capable of making plasma generation close to a more uniform state and also removing products deposited inside exhaust piping nearby a vacuum pump.CONSTITUTION: An exhaust piping device 100 is used as a part of exhaust piping arranged between a process chamber and a vacuum pump exhausting the process chamber. The exhaust piping device 100 comprises a dielectric pipe (inner pipe 190), a high frequency electrode 104, and a plasma generation circuit 106. The high frequency electrode 104 has a metal thin plate 50 arranged on an outer peripheral side of the dielectric pipe, a cushioning member 52 arranged on an outer peripheral side of the metal thin plate, and an electrically conductive hollow structure 54 arranged on an outer peripheral side of the cushioning member, and is applied with a high frequency voltage. The plasma generation circuit 106 generates plasma inside the dielectric pipe.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to an exhaust piping device. [Background technology]

[0002] In a film formation system, such as a chemical vapor deposition (CVD) system, a source gas is introduced into a film formation chamber to form a desired film on a substrate placed in the film formation chamber. The source gas remaining in the film formation chamber is then exhausted by a vacuum pump via an exhaust pipe. During this process, products of the source gas can deposit in the exhaust pipe, causing problems such as blockage of the exhaust pipe, or deposit in the vacuum pump downstream of the exhaust pipe, causing the vacuum pump to stop. To remove such deposits, a cleaning process using a remote plasma source (RPS) system is performed. However, because RPS systems are generally focused on cleaning the inside of the film formation chamber, their cleaning performance is insufficient to clean the products that deposit in the exhaust pipe near the vacuum pump and in the vacuum pump, which are far from the RPS system.

[0003] This technique involves applying a high-frequency voltage to a high-frequency electrode disposed around a conduit made of an insulating material such as ceramic or quartz to generate plasma inside the conduit. This plasma is then used to remove unreacted gases and waste gases generated during ashing, etching, deposition, cleaning, and nitriding processes. However, if the contact between the conduit and the high-frequency electrode is insufficient, the plasma generation inside the conduit may be uneven. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent Application Publication No. 2007 / 0074662 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-508029 [Patent Document 3] U.S. Patent Application Publication No. 2021 / 0249238 Summary of the Invention [Problem to be solved by the invention]

[0005] Embodiments of the present invention provide an exhaust piping device that can achieve closer to uniform plasma generation and remove products that deposit inside the exhaust piping near the vacuum pump. [Means for solving the problem]

[0006] An exhaust piping device according to an embodiment is an exhaust piping device used as part of an exhaust piping arranged between a process chamber and a vacuum pump that exhausts the interior of the process chamber, The device comprises a dielectric tube, a radio-frequency electrode, and a plasma generation circuit. The radio-frequency electrode has a metal thin plate arranged on the outer periphery of the dielectric tube, a buffer member arranged on the outer periphery of the metal thin plate, and a conductive hollow structure arranged on the outer periphery of the buffer member, and a radio-frequency voltage is applied to the electrode. The plasma generation circuit generates plasma inside the dielectric tube. Further, the thickness of the metal thin plate is thinner than the thickness of the hollow structure, The thin metal plate and the hollow structure are disposed so as to be electrically connected to each other. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is a configuration diagram showing an example of the configuration of an exhaust system of the semiconductor manufacturing apparatus according to the first embodiment. [Figure 2] 1 is a cross-sectional view of an example of an exhaust piping device according to a first embodiment, as viewed from the front. [Figure 3] 1 is a cross-sectional view of an example of an exhaust piping device according to a first embodiment, viewed from above. [Figure 4] FIG. 2 is a diagram illustrating an example of the configuration of a high-frequency electrode according to the first embodiment. [Figure 5] 3A to 3C are diagrams illustrating an example of a method for assembling a high-frequency electrode according to the first embodiment. [Figure 6]FIG. 10 is a top view showing an example of a plasma generation state in Comparative Example 1 of the first embodiment. [Figure 7] FIG. 2 is a top view showing an example of a plasma generation state in the first embodiment. [Figure 8] 10 is a graph illustrating the relationship between the inner tube temperature and the cleaning processing time. [Figure 9] FIG. 2 is a diagram showing an example of a layout of cooling pipes in the first embodiment. [Figure 10] FIG. 10 is a front view of an example of an exhaust piping device in a comparative example 2 of the first embodiment. [Figure 11] FIG. 10 is a cross-sectional view of an example of an exhaust piping device according to a second embodiment, as viewed from the front. [Figure 12] FIG. 10 is a cross-sectional view of an example of an exhaust piping device according to a third embodiment, as viewed from the front. DETAILED DESCRIPTION OF THE INVENTION

[0008] (First embodiment) FIG. 1 is a diagram illustrating an example of the exhaust system configuration of a semiconductor manufacturing apparatus according to the first embodiment. In the example of FIG. 1, a film-forming apparatus, e.g., a chemical vapor deposition (CVD) apparatus 200, is shown as the semiconductor manufacturing apparatus. The example of FIG. 1 illustrates a multi-chamber CVD apparatus 200 having two film-forming chambers 202. In the CVD apparatus 200, a semiconductor substrate 204 (204a, 204b) on which a film is to be formed is placed in the film-forming chamber 202, which is controlled to a desired temperature. A vacuum is then drawn through exhaust pipes 150, 152 by a vacuum pump 400, and source gases are supplied into the film-forming chamber 202, which is controlled to a desired pressure by a pressure-regulating valve 210. In the film-forming chamber 202, a desired film is formed on the substrate 204 by a chemical reaction of the source gases. For example, a silane (SiH4)-based gas is introduced as a main source gas to form a silicon oxide film (SiO film) or a silicon nitride film (SiN film). In addition, for example, tetraethoxysilane (TEOS) gas or the like is introduced as a main raw material gas to form a silicon oxide film (SiO film). When forming these films, products resulting from the raw material gas are deposited in the film formation chamber 202 and the exhaust pipes 150 and 152. Therefore, in the film formation process cycle, a cleaning process is performed in addition to the film formation process.

[0009] In the cleaning process, a cleaning gas such as nitrogen trifluoride (NF3) gas and a purge gas such as argon (Ar) gas are supplied to a remote plasma source (RPS) device 300 located upstream of the film formation chamber 202, and fluorine (F) radicals are generated by plasma. The F radicals are then supplied (diffused) into the film formation chamber 202 and the exhaust pipe 150, thereby cleaning the deposited products. Silicon tetrafluoride (SiF4), for example, generated after decomposing the deposits during cleaning is highly volatile and is therefore exhausted from the vacuum pump 400 through the exhaust pipes 150 and 152.

[0010] However, F radicals have difficulty reaching portions of the exhaust pipes 150, 152 that are far from the film formation chamber 202, resulting in a deterioration in cleaning performance. In particular, the pressure is low near the intake port of the vacuum pump 400, resulting in a low cleaning rate. As a result, the exhaust pipes 150, 152 may become clogged with deposited products. Furthermore, the deposited products in the vacuum pump 400 may fill the gap between the rotor and the casing, causing an overload condition and causing the vacuum pump 400 to stop. Therefore, in the first embodiment, as shown in FIG. 1 , the exhaust pipe device 100 is disposed closer to the intake port of the vacuum pump 400 than the film formation chamber 202.

[0011] 1, the exhaust piping device 100 of the first embodiment is used as part of an exhaust piping system including exhaust piping 150, 152 disposed between a film formation chamber 202 (an example of a process chamber) and a vacuum pump 400 that evacuates the film formation chamber 202. The exhaust piping device 100 includes an outer pipe 102, a dielectric inner pipe 190 (dielectric pipe), and a plasma generation circuit 106. The outer pipe 102 is made of the same material as the ordinary exhaust piping 150, 152. For example, stainless steel such as SUS304 is used. However, from the viewpoint of corrosion resistance against cleaning gases, SUS316 steel is more preferably used as the material for the outer pipe 102. Furthermore, the outer pipe 102 is made of the same size as the ordinary exhaust piping 150, 152. However, the size is not limited thereto. The outer pipe 102 may be larger or smaller than the ordinary exhaust piping 150, 152.

[0012] Flanges are disposed at both ends of the inner pipe 190 and the outer pipe 102, with one end connected to an exhaust pipe 150 having a flange of the same size, and the other end connected to an exhaust pipe 152 having a flange of the same size. Clamps and other devices used to secure the flange of the exhaust pipe device 100 to the flanges of the exhaust pipes 150 and 152 are not shown in FIG. 1 . This also applies to the following figures. Also, seals such as O-rings used to connect the exhaust pipes 150 and 152 are not shown. In the following embodiments, the exhaust pipe 152 is sandwiched between the exhaust pipe device 100 and the vacuum pump 400, but this is not limiting. The exhaust pipe device 100 may also be disposed directly at the intake port of the vacuum pump 400. The dielectric inner pipe 190 is disposed inside the outer pipe 102. The plasma generating circuit 106 uses an electrode (described later) arranged on the outer periphery of the inner tube 190 to generate a capacitively coupled plasma (CCP) inside the inner tube 190 made of a dielectric material.

[0013] FIG. 2 is a cross-sectional view of an example of an exhaust piping device according to the first embodiment, as viewed from the front. FIG. 3 is a cross-sectional view of an example of an exhaust piping device according to the first embodiment, as viewed from the top. In FIG. 2, the cross-sectional structure of the exhaust piping device 100 is shown, and cross sections of other components are not shown. This is the same for each cross-sectional view viewed from the front. In FIGS. 2 and 3, the exhaust piping device 100 has a double-pipe structure consisting of an outer pipe 102 and an inner pipe 190 made of a dielectric material and disposed inside the outer pipe 102. The inner pipe 190 has a shape similar to that of the outer pipe 102. In the example of FIGS. 2 and 3, the outer pipe 102 has a cylindrical (annular) cross section, and the inner pipe 190 has a circular (annular) cross section similar to that of the outer pipe 102. Alternatively, the outer pipe 102 may have a cylindrical (annular) cross section, and the inner pipe 190 may have a rectangular cross section similar to that of the outer pipe 102.

[0014] The inner tube 190 is disposed across the space 36 from the inner wall of the outer tube 102. The dielectric material for the inner tube 190 may be any material as long as it has a dielectric constant greater than that of air. Suitable materials for the inner tube 190 include, for example, quartz, alumina (Al2O3), yttria (Y2O3), hafnia (HfO2), zirconia (ZrO2), magnesium oxide (MgO), and aluminum nitride (AlN). The thickness of the inner tube 190 may be set as appropriate as long as it does not impair exhaust performance.

[0015] A high-frequency electrode 104 is arranged inside the outer tube 102 and on the outer periphery of the inner tube 190. The high-frequency electrode 104 has a thin metal plate 50 arranged on the outer periphery of the inner tube 190, which serves as a dielectric tube, a buffer member 52 arranged on the outer periphery of the thin metal plate 50, and a conductive hollow structure 54 arranged on the outer periphery of the buffer member 52. The thin metal plate 50 and hollow structure 54 are arranged so as to be electrically conductive.

[0016] When the high-frequency electrode 104 is disposed on the outer periphery of the inner tube 190, the high-frequency electrode 104 is formed into a shape that matches the outer periphery of the inner tube 190. For example, for an inner tube 190 that is tubular (annular) with a circular cross section, a high-frequency electrode 104 that is tubular (annular) with a circular cross section of the same type is used. Furthermore, as shown in FIG. 2, the length of the high-frequency electrode 104 is formed to be shorter than the length of the inner tube 190. As shown in the example of FIG. 2, the high-frequency electrode 104 is disposed in the center in the height direction of the inner tube 190, leaving gaps at the upper and lower ends.

[0017] A flange 19 is disposed on the end side of the inner pipe 190. In the example of FIG. 2, piping flanges 19 are disposed on both ends of the inner pipe 190. The flange 19 on the upstream side with respect to the gas flow is fixed to the flange of the exhaust pipe 150. The flange 19 on the downstream side with respect to the gas flow is fixed to the flange of the exhaust pipe 152. For both flanges 19, for example, the same piping material as that of normal exhaust pipes 150, 152 is used. For example, a stainless steel material such as SUS304 is used. However, from the viewpoint of corrosion resistance against cleaning gas, SUS316 steel is more preferably used as the material of the flange 19.

[0018] 2 , the space between the outer pipe 102 and the inner pipe 190 is isolated from the atmosphere and the space inside the inner pipe 190 by sealing mechanisms 16 disposed at the upper and lower ends of the inner pipe 190 and the outer pipe 102 covering the outer periphery of the inner pipe 190. The sealing mechanisms 16 are preferably configured, for example, as follows. Each sealing mechanism 16 has a protrusion 10, an O-ring holder 11, an O-ring 12, and an O-ring 14. Each protrusion 10 is provided in a ring shape on the surface of each flange 19 at both ends of the inner pipe 190, and extends from the surface of each flange 19 to the high-frequency electrode 104 on the outside of the inner pipe 190. The O-ring 14 on the exhaust pipe 150 side (upstream side) is disposed between the flange 19 and the flange surface on the exhaust pipe 150 side (upstream side) of the outer pipe 102. The O-ring 14 on the exhaust pipe 152 side (downstream side) is disposed between the flange surface of the external pipe 102 on the exhaust pipe 152 side (downstream side) and the flange 19. In this case, on the upstream side of the exhaust piping device 100, the flange of the external pipe 102 and the flange of the pipe 150 are preferably clamped together with the flange 19 sandwiched between them. On the downstream side of the exhaust piping device 100, the flange of the external pipe 102 and the flange of the pipe 152 are preferably clamped together with the flange 19 sandwiched between them. The O-ring 14 shields the atmosphere inside the external pipe 102 from the atmosphere.

[0019] Each O-ring 12 is disposed in a pressed state between the outer peripheral surface of the end of the inner tube 190 and the inner peripheral surface of the convex portion 10. Therefore, the inner diameter of the convex portion 10 is larger than the outer diameter of the inner tube 190 and smaller than the inner diameter of the outer tube 102. Each O-ring 12 is pressed by an O-ring retainer 11. The O-ring retainer 11 may be formed of a single member, or, as shown in FIG. 2, may be formed of a combination of two members: a ring-shaped member disposed between the outer peripheral surface of the end of the inner tube 190 and the inner peripheral surface of the convex portion 10, and an outer member supporting the ring-shaped member. This shields the atmosphere inside the inner tube 190 from the space 36 between the outer tube 102 and the inner tube 190 via the O-ring 12.

[0020] In the first embodiment, by forming a sealed double-pipe structure of the outer pipe 102 and the inner pipe 190 as described above, even if the dielectric inner pipe 190 is damaged, it is possible to prevent the gas flowing through the exhaust pipe from leaking into the atmosphere. Similarly, it is possible to prevent the atmosphere from rushing into the exhaust pipe. Furthermore, even when the space between the outer pipe 102 and the inner pipe 190 is controlled to atmospheric pressure, the volume of the space between the outer pipe 102 and the inner pipe 190 is small, so it is possible to prevent the atmosphere from flowing in to an extent that would cause a breakdown of the vacuum pump 400.

[0021] 2 and 3 show a double-pipe structure in which the outer pipe 102 is disposed outside the inner pipe 190, but the present invention is not limited to this. A state in which the outer pipe 102 is not provided is not excluded.

[0022] 4 is a diagram showing an example of the configuration of the high-frequency electrode in Embodiment 1. As described above, the high-frequency electrode 104 has the thin metal plate 50, the buffer member 52, and the hollow structure .

[0023] The thin metal plate 50 is formed to be thinner than the hollow structure 54. This makes it easier to bend than the hollow structure 54. Specifically, the thin metal plate 50 is formed by bending a thin metal plate into an annular shape, for example, a circular shape. A thin plate having a thickness of, for example, about 0.1 mm to 3 mm is used. Both ends of the thin plate in the bending direction are formed with flanges folded back outward. Bolt holes are formed in the flanges. In the example of FIG. 4, bolt holes are formed in two places, one at the top and one at the bottom. A material with low resistivity and flexibility is suitable for the material of the thin metal plate 50. For example, copper (Cu) or aluminum (Al) is suitable. The low resistivity makes it easier for the entire surface to be electrically equivalent to the hollow structure 54 even when the thickness is thin. Furthermore, the flexibility makes it easier to bend. By using a material softer than stainless steel, for example, copper, the thin metal plate can be easily bent even when it is 3 mm thick.

[0024] The hollow structure 54 is formed by combining one half-hollow structure 54-1 and the other half-hollow structure 54-2, which are formed by splitting the circumference of a cylindrical shape in half. A cavity 34 is formed within the hollow structure 54. Specifically, the cavity 34 is formed in each of the half-hollow structures 54-1 and 54-2. The cavity 34 is preferably formed throughout the entire hollow structure 54. The hollow structure 54 is formed from a conductive material. Furthermore, in order to allow cooling water to flow through the cavity 34 as described below, a material with high conductivity, such as copper, is used. Alternatively, aluminum or steel such as SUS304 or SUS316 may be used. The hollow structure 54 guides the high-frequency potential applied from the feedthrough 111 to the thin metal plate 50 and functions as a heat exchanger, which is part of the cooling mechanism. The half-hollow structures 54-1 and 54-2 each have a flange for attachment at their ends. Bolt holes are formed in the flange. In the example of Fig. 4, two bolt holes are formed at the top and bottom. The bolt holes in the half hollow structure 54-1 and the half hollow structure 54-2 are formed so as to be offset from the bolt holes in the metal sheet 50.

[0025] The buffer member 52 is sandwiched between the thin metal plate 50 and the hollow structure 54 and functions as a buffer between them. The buffer member 52 is formed by combining one half buffer member 52-1 and the other half buffer member 52-2, which are obtained by splitting the circumference of a cylindrical shape in half. The buffer member 52 is preferably made of a material with high thermal conductivity to efficiently transfer heat from the inner tube 190, which serves as a dielectric tube, to the hollow structure 54. A thermal conductivity of, for example, approximately 1 to 10 W / m·K is preferable. Furthermore, the buffer member 52 must be heat-resistant enough to withstand the heat generated by the dielectric. For example, a heat resistance of approximately 100 to 150°C is preferable. A suitable material having these functions is, for example, a sheet-like silicone polymer. Alternatively, a silicone gel material may be applied to the inner surface of the hollow structure 54 to form the buffer member 52. The thickness of the buffer member 52 is preferably, for example, approximately 0.1 to 0.5 mm.

[0026] 5 is a diagram showing an example of how to assemble the high-frequency electrode in the first embodiment. First, a thin metal plate 50 is attached to the outer periphery of an inner tube 190. The thin metal plate 50 can be tightly attached to the outer periphery of the inner tube 190 by passing screws 56 through the bolt holes in the flanges and tightening the flanges together. Next, the half hollow structure 54-1 with the half buffer member 52-1 disposed on its inner surface and the half hollow structure 54-2 with the half buffer member 52-2 disposed on its inner surface are attached from the outer periphery so as to sandwich the metal sheet 50. Then, screws 58 are passed through the bolt holes in the flanges of the half hollow structure 54-1 and the half hollow structure 54-2 and tightened so as to bring the flanges closer together, thereby attaching the hollow structure 54 to the outer periphery of the metal sheet 50 via the buffer member 52. 3 As shown in Fig. 1, the assembly is performed so that the tip of the screw 56 that contacts the metal sheet 50 contacts the hollow structure 54. This allows the hollow structure 54 to be electrically connected to the metal sheet 50. Note that the half hollow structure 54-1 and the half hollow structure 54-2 are also electrically connected to each other via the screw 58.

[0027] Although the case where the hollow structure 54 and the thin metal plate 50 are electrically connected using the screws 56 has been described, the present invention is not limited to this. For example, conductive nanoparticles may be added to the silicone polymer that forms the buffer member 52. In this way, it is also preferable to configure the buffer member 52 so that it connects the hollow structure 54 and the thin metal plate 50.

[0028] 2 and 3, a radio frequency (RF) electric field is applied to the radio frequency electrode 104 by the plasma generation circuit 106. Specifically, a feed terminal 111 (an example of a radio frequency feed terminal) is introduced into the external tube 102 from a feed terminal port 105 connected to the outer circumferential surface of the external tube 102, and the feed terminal 111 is connected to the radio frequency electrode 104. In the first embodiment, the flange 19 acts as a ground electrode. The external tube 102 is also grounded.

[0029] The plasma generation circuit 106 generates plasma inside the inner tube 190 by using capacitive coupling between the radio-frequency electrode 104 and the ground electrode. Specifically, with the flange 19 grounded (ground potential applied) as the ground electrode, the plasma generation circuit 106 applies a radio-frequency (RF) voltage to the hollow structure 54 of the radio-frequency electrode 104 via the lead-in terminal 111. As a result, the thin metal plate 50, which is electrically connected to the hollow structure 54, has the same electrical potential as the hollow structure 54. Therefore, a capacitively coupled plasma (CCP) is generated inside the dielectric inner tube 190 due to the potential difference between the radio-frequency electrode 104 (thin metal plate 50) and the flange 19. In addition, in the cleaning process, since a cleaning gas such as the above-mentioned NF gas is supplied upstream, the remaining gas is used to generate F radicals by plasma inside the inner tube 190. These F radicals then remove products deposited inside the inner tube 190. This enables high cleaning performance to be achieved inside the exhaust piping.

[0030] Thereafter, for example, SiF4, which is generated after decomposition of the deposits by the F radicals, is highly volatile and is therefore exhausted by the vacuum pump 400 through the exhaust pipe 152. Also, some of the radicals generated in the exhaust pipe device 100 enter the vacuum pump 400 through the exhaust pipe 152 and clean the products that have accumulated inside the vacuum pump 400. This makes it possible to reduce the amount of products that accumulate inside the vacuum pump 400. For example, F radicals generated by plasma generated on a part of the inner wall surface on the lower end side of the inner tube 190 can be made to enter the vacuum pump 400 with little consumption inside the inner tube 190.

[0031] FIG. 6 is a top view showing an example of plasma generation in Comparative Example 1 of the first embodiment. In Comparative Example 1 shown in FIG. 6, the thin metal plate 50 and buffer member 52 of the examples shown in FIGS. 2 and 3 are not provided, and the hollow structure 354 is directly disposed around the outer periphery of the inner tube 190. In Comparative Example 1, when the hollow structure 354 is attached around the inner tube 190, there are contact and non-contact areas between the inner periphery of the hollow structure 354 and the outer periphery of the inner tube 190. When a high-frequency voltage is applied to the hollow structure 354, the high-frequency electric field is strong at the contact areas, resulting in strong plasma emission, whereas the high-frequency electric field is weak at the non-contact areas, resulting in weak plasma emission. Thus, with the configuration of Comparative Example 1, plasma does not spread to the non-contact areas, resulting in non-uniform plasma generation. As a result, the cleaning effect is reduced.

[0032] 7 is a top view showing an example of the state of plasma generation in the first embodiment. In the first embodiment, the thin metal plate 50, which is thinner than the hollow structure 54, can be brought into close contact with the inner tube 190, thereby preventing any areas of non-contact between the inner circumferential surface of the thin metal plate 50 and the outer circumferential surface of the inner tube 190. When a high-frequency voltage is applied to the hollow structure 54, the entire conductive thin metal plate 50 can be brought to approximately the same electrical potential as the hollow structure 54. As a result, as shown in FIG. 7, uniform plasma generation can be expected in the circumferential direction without any areas of weak light emission.

[0033] In the above example, a double-tube structure is configured to prevent leakage and air intrusion due to damage to the inner tube 190 by a dielectric. One cause of damage to the inner tube 190 by a dielectric is a rise in temperature of the inner tube 190.

[0034] FIG. 8 is a graph illustrating the relationship between the inner tube temperature and the cleaning process time. In FIG. 8, the vertical axis represents the temperature of the inner tube in the exhaust piping, and the horizontal axis represents the continuous process time for the exhaust piping during the cleaning process. The graph shown in FIG. 8 illustrates an example in which the inner tube 190 is used without being cooled. During the cleaning process, a high-frequency voltage is applied to the high-frequency electrode 104, causing the temperature of the high-frequency electrode 104 to rise. This causes the temperature of the inner tube 190, which is a dielectric tube in which plasma is generated, to rise. As shown in the graph in FIG. 8, if the process is continued without cooling, the temperature rises as the cleaning process time increases, and the inner tube 190 may eventually be damaged. To prevent damage to the dielectric inner tube 190 due to the temperature rise, it is desirable to cool the inner tube 190. Therefore, a configuration capable of suppressing the temperature rise of the inner tube 190 in the first embodiment will be described below.

[0035] In the first embodiment, a cooling mechanism is provided. The cooling mechanism introduces cooling water (an example of a refrigerant) into the space 34 within the hollow structure 54, and cools the inner tube 190 (dielectric tube) via the buffer member 52 and the thin metal plate 50.

[0036] FIG. 9 is a diagram showing an example of the layout of cooling piping in the first embodiment. As shown in the example of FIGS. 2 and 3, a cavity 34 is formed in a hollow structure 54. The cavity 34 is preferably formed throughout the entire hollow structure 54. As described above, the hollow structure 54 is formed by combining a half hollow structure 54-1 and a half hollow structure 54-2. The cooling piping 30 is disposed in the lower part of the cavity 34 in the half hollow structure 54-1. The cooling piping 32 is disposed in the upper part of the cavity 34 in the half hollow structure 54-2. The cooling piping 37 is disposed between the upper part of the cavity 34 in the half hollow structure 54-1 and the lower part of the cavity 34 in the half hollow structure 54-2. To facilitate the assembly of the half hollow structure 54-1 and the half hollow structure 54-2, it is preferable to use a flexible tube as the cooling piping 37. However, this is not a limitation. After assembling the half hollow structural body 54-1 and the half hollow structural body 54-2, the fixed cooling pipe 37 that is difficult to bend freely may be attached.

[0037] 2, a cavity 31 is formed inside the flange 19 on the exhaust pipe 152 side (downstream side). Similarly, a cavity 33 is formed inside the flange 19 on the exhaust pipe 150 side (upstream side). The cavities 31, 33 may be formed throughout each flange 19 or only in part. For example, two cylindrical cavities extending in a straight line may be formed so as to be connected in an L-shape. The cavity 31 has an inlet provided on a side surface of the flange 19 and an outlet provided on the side of the space 36 between the outer pipe 102 and the inner pipe 190. The cavity 33 has an inlet provided on the side of the space 36 between the outer pipe 102 and the inner pipe 190 and an outlet provided on the side surface of the flange 19. A cooling pipe 30 connects the outlet of the cavity 31 to a lower part of the cavity 34 in the hollow structure 54 (e.g., half hollow structure 54-1). A cooling pipe 37 connects the upper part of the cavity 34 of the half hollow structure 54-1 to the lower part of the cavity 34 of the half hollow structure 54-2. A cooling pipe 32 connects the upper part of the cavity 34 in the half hollow structure 54-2 to the inlet of the cavity 33. The flange 19 in which the cavity 31 is formed, the flange 19 in which the cavity 33 is formed, the cooling pipes 30, 32, and 37, and the hollow structure 54 in which the cavity 34 is formed constitute part of a cooling mechanism.

[0038] The cooling water supplied to the side of the flange 19 on the exhaust pipe 152 side (downstream side) passes through the cavity 31 in the flange 19 on the exhaust pipe 152 side (downstream side), and then passes through the cooling pipe 30 to reach the lower part of the cavity 34 in the half hollow structure 54-1. The cooling water supplied to the lower part of the cavity 34 in the half hollow structure 54-1 accumulates in the cavity 34 from bottom to top. The cooling water that overflows from the upper part of the cavity 34 in the half hollow structure 54-1 passes through the cooling pipe 37 and is supplied to the lower part of the cavity 34 in the half hollow structure 54-1. The cooling water supplied to the lower part of the cavity 34 in the half hollow structure 54-2 accumulates in the cavity 34 from bottom to top. The cooling water that overflows from the upper part of the cavity 34 in the half hollow structure 54-2 passes through the cooling pipe 32 and advances to the cavity 33 in the flange 19 on the exhaust pipe 150 side (upstream side). The water then passes through a cavity 33 in the flange 19 and is drained from an outlet on the side of the flange 19 .

[0039] While the cooling water is flowing, the plasma generation circuit 106 uses the high-frequency electrode 104 to generate plasma inside the inner tube 190. The plasma generation circuit 106 applies a high-frequency voltage to the high-frequency electrode 104. At this time, the cooling water flowing through the hollow structure 54 is used to cool the inner tube 190, which is a dielectric tube whose temperature rises due to plasma generation inside, and the space 36 between the inner tube 109 and the outer tube 102. This directly cools the high-frequency electrode 104, whose temperature rises due to the application of the high-frequency voltage. In the first embodiment, a buffer member 52 with high thermal conductivity is sandwiched between the hollow structure 54 and the metal thin film 50, ensuring close contact with each other. Therefore, by directly cooling the hollow structure 54, the metal thin film 50 can be efficiently cooled. Furthermore, the inner tube 109, which is in close contact with the inner circumferential surface of the metal thin film 50, can be efficiently cooled. This suppresses the temperature rise in the inner tube 190.

[0040] Fig. 10 is a front view of an example of an exhaust piping device in Comparative Example 2 of the first embodiment. Comparative Example 2 in Fig. 10 shows a case where a high-frequency electrode 304 is disposed in the space between the dielectric tube 390 and an outer tube 302 on the outer periphery of the dielectric tube 390. In addition, piping flanges 319 acting as ground electrodes are disposed at both ends of the dielectric tube 390. Then, a capacitively coupled plasma (CCP) is generated by applying a radio frequency (RF) voltage to the high-frequency electrode 304 using the flange 319 as the ground electrode. In this configuration, capacitive coupling occurs between the flange 319 and the high-frequency electrode 304, causing discharge.

[0041] 10, it is also conceivable to cool the outer circumferential surface of the external tube 302, which is disposed on the outer circumferential side of the dielectric tube 390 and the high-frequency electrode 304, by supplying cooling water. However, even if the outside of the external tube 302 is cooled, it is difficult to sufficiently cool the space between the external tube 302 and the dielectric tube 390 via the external tube 302. Therefore, cooling the external tube 302 increases the temperature of the dielectric tube 390, which may cause damage. In contrast to this, in the first embodiment, the outer peripheral surface of the inner tube 190 is directly cooled by the high-frequency electrode 104, so that the temperature rise of the inner tube 190 can be suppressed compared to when cooling is performed from the outside of the outer tube 102. Note that in the first embodiment, if a double-tube structure in which an outer tube is disposed outside the inner tube is not formed, it is also preferable to configure the hollow structure 54 in which the cavity 34 is formed to be cooled as part of a cooling mechanism so that the temperature rise of the inner tube 190 can be suppressed.

[0042] As described above, according to the first embodiment, it is possible to make the plasma generation closer to a uniform state, and also to remove the by-products that accumulate inside the exhaust pipe near the vacuum pump.

[0043] (Second embodiment) In the configuration of Comparative Example 2 shown in FIG. 10 , capacitive coupling occurs between the flange 319 and the high-frequency electrode 304, resulting in discharge. Discharge can occur not only inside the dielectric tube 390 but also outside the dielectric tube 390, for example, on the atmospheric pressure side. Therefore, it is desirable to increase the distance L3 between the flange 319 (ground electrode) and the high-frequency electrode 304 to a degree that prevents discharge on the atmospheric pressure side. If the distance L3 between the flange 319 (ground electrode) and the high-frequency electrode 304 is large, plasma generation becomes difficult when the gas flow rate or pressure inside the dielectric tube 390 increases, resulting in unstable discharge. To address this issue, reducing the electrode size of the high-frequency electrode 304 in the gas flow direction, increasing the voltage, and / or reducing the distance L3 between the flange 319 (ground electrode) and the high-frequency electrode 304 makes it easier to generate plasma, but this increases the likelihood of abnormal discharge (arcing) on the atmospheric pressure side.

[0044] Therefore, in the second embodiment, the ground electrode is arranged so that the distance to the high-frequency electrode 104 is smaller on the inside side of the inner tube 190 than on the outside side.

[0045] Fig. 11 is a cross-sectional view of an example of an exhaust piping device according to the second embodiment, as seen from the front. A cross-sectional view of an example of an exhaust piping device according to the second embodiment, as seen from the top, is omitted. Fig. 11 is the same as Fig. 2, except that ring-shaped protrusions 18 extending from the surfaces of the flanges 19 toward the high-frequency electrode 104 are respectively arranged on the inside of the inner pipe 190.

[0046] Each protrusion 18 is made of a conductive material and constitutes a part of the ground electrode. For example, each protrusion 18 is formed integrally with the flange 19 to which it is connected. Alternatively, it may be formed separately from the flange 19 as long as it is electrically conductive with the flange 19. Furthermore, when each O-ring holder 11 is made of a conductive material, each O-ring holder 11 constitutes a part of the ground electrode by abutting against the protrusion 10.

[0047] 11 , on the outside of the inner tube 190, the tip of the protrusion 10 or the exposed surface of the O-ring holder 11 facing the high-frequency electrode 104 is closest to the high-frequency electrode 104. Therefore, the protrusion 18 is formed so that the distance L1 between the tip of the protrusion 18 and the high-frequency electrode 104 is smaller than the distance L2 between the tip of the protrusion 10 on the outside of the inner tube 190 or the exposed surface of the O-ring holder 11 facing the high-frequency electrode 104 and the high-frequency electrode 104. If the protrusion 10 is not present, the protrusion 18 is positioned so that the distance L1 between the tip of the protrusion 18 and the high-frequency electrode 104 is smaller than the distance between the flange surface on the outside of the inner tube 190 and the high-frequency electrode 104. As a result, when a high-frequency voltage is applied to the high-frequency electrode 104, a discharge occurs first between the protrusion 18 and the high-frequency electrode 104. Therefore, it is possible to generate a plasma by capacitive coupling inside the inner tube 190 without applying a voltage large enough to cause abnormal discharge (arcing) on the atmospheric pressure side, for example. By reducing the distance between the electrodes on the vacuum side, arcing can be suppressed and the ignition ability and stability of the plasma can be improved.

[0048] It is desirable that the protrusion 18 be disposed so that the distance L 1 between the tip of the protrusion 18 and the high-frequency electrode 104 is smaller than the distance between the grounded outer tube 102 and the high-frequency electrode 104 .

[0049] The other configurations are the same as those in FIG.

[0050] As described above, according to the second embodiment, in addition to the same effects as those of the first embodiment, it is possible to remove by-products that accumulate inside the exhaust pipe near the vacuum pump while avoiding abnormal discharge such as arcing.

[0051] (Third embodiment) In the above-described embodiments, a configuration has been described in which the inner tube 190, which is in close contact with the high-frequency electrode 104, is directly cooled by flowing cooling water into the cavity 34 in the hollow structure 54. A cooling mechanism in a third embodiment will be described in which a configuration is furthermore provided in which the space 36 between the inner tube 190 and the outer tube 102 is cooled.

[0052] FIG. 12 is a cross-sectional view of an example of an exhaust piping device according to the third embodiment, as viewed from the front. A cross-sectional view of an example of an exhaust piping device according to the third embodiment, as viewed from the top, is omitted. FIG. 12 is the same as FIG. 11, except that a gas inlet 41, a valve 40 (or a check valve 42), a gas outlet 43, and a valve 44 (or a check valve 46) are further added. The cooling mechanism according to the third embodiment introduces a cooling gas (another example of a refrigerant) from a gas inlet 41 located on the lower side of the outer circumferential surface of the outer pipe 102 via the valve 40 (or the check valve 42) into the space 36 between the inner pipe 109 and the outer pipe 102. Then, the cooling gas is discharged to the outside from a gas outlet 43 located on the upper side of the outer circumferential surface of the outer pipe 102 via the valve 44 (or the check valve 46). By flowing such cooling gas into the space 36 between the inner tube 109 and the outer tube 102, the inner tube 190, which is a dielectric tube whose temperature rises due to plasma generation inside, and the space 36 between the inner tube 109 and the outer tube 102 are cooled. Cooling the inner tube 109 with the cooling gas can further enhance the effect of suppressing damage to the inner tube 109. For example, air is used as the cooling gas.

[0053] The cooling gas is introduced into the space 36 between the inner tube 109 and the outer tube 102 at a pressure higher than atmospheric pressure. Therefore, the pressure in the space 36 between the inner tube 109 and the outer tube 102 is controlled to a pressure higher than the pressure in the space inside the inner tube 109 and atmospheric pressure. The pressure in the space 36 between the inner tube 109 and the outer tube 102 is measured by a pressure sensor 48 through a vent 47 arranged on the outer surface of the outer tube 102, and pressure fluctuations in the space 36 are monitored. If the inner tube 190, which is a dielectric tube whose temperature rises due to plasma generation inside, were to break, a large amount of cooling gas would flow into the vacuum side, causing a vacuum breakdown. Therefore, the pressure sensor 48 detects breakage of the inner tube 190.

[0054] Specifically, when a pressure drop is detected by the pressure sensor 48, the valves 40 and 44 are controlled to shut off. This minimizes the inflow of cooling gas into the exhaust line. If a check valve 42 is used instead of the valve 40, the check valve 42 has a cracking pressure set so that the pressure difference between the primary and secondary pressures is greater than 0.1 MPa and shuts off at a pressure lower than the cooling gas supply pressure. When the supply of cooling gas stops at the supply source, the primary pressure (the primary side of the check valve) becomes atmospheric pressure, the secondary pressure (inside the external pipe 102) becomes lower than atmospheric pressure (the pressure drops below atmospheric pressure due to damage), and the pressure difference becomes 0.1 MPa or less. Therefore, if the cracking pressure is set to 0.1 MPa < supply pressure, cooling gas will not flow. Therefore, if the supply of cooling gas is stopped at the supply source in response to detection of damage to the inner pipe 190, atmospheric air will not flow into the external pipe 102 even if the primary side is open to the atmosphere. Furthermore, if a check valve 46 is used instead of the valve 44, if the inner pipe 190 is damaged, the primary pressure will be lower than the secondary pressure, blocking the flow path. This prevents atmospheric air from flowing into the outer pipe 102.

[0055] The other configurations are the same as those in FIG.

[0056] As described above, according to the third embodiment, in addition to the same effects as those of the first and second embodiments, the cooling effect of the inner pipe 190 can be further improved.

[0057] The above describes the embodiments with reference to specific examples. However, the present invention is not limited to these specific examples. For example, in the embodiments of the present invention, the exhaust piping device may be applied to semiconductor manufacturing equipment other than film formation equipment, such as an etching equipment.

[0058] In addition, all exhaust piping devices that include the elements of the present invention and that can be appropriately modified by those skilled in the art are included within the scope of the present invention. [Explanation of symbols]

[0059] 18 convex portion, 19 flange, 30, 32, 37 cooling pipe, 31, 33, 34 cavity, 40, 44 valve, 41 gas inlet, 42, 46 check valve, 43 gas outlet, 50 metal thin plate, 52 buffer member, 54 hollow structure, 56, 58 screw, 100 exhaust pipe device, 102 outer pipe, 104 high frequency electrode, 105 introduction terminal port, 106 plasma generation circuit, 111 introduction terminal, 150, 152 pipe, 190 inner pipe, 202 film formation chamber, 400 vacuum pump

Claims

1. An exhaust piping device used as part of an exhaust piping arranged between a process chamber and a vacuum pump that exhausts the inside of the process chamber, a dielectric tube; a high-frequency electrode to which a high-frequency voltage is applied, the high-frequency electrode including a metal thin plate disposed on the outer periphery of the dielectric tube, a buffer member disposed on the outer periphery of the metal thin plate, and a conductive hollow structure disposed on the outer periphery of the buffer member; a plasma generating circuit that generates plasma inside the dielectric tube; Equipped with the thickness of the metal sheet is smaller than the thickness of the hollow structure; The metal sheet and the hollow structure are arranged to be electrically connected to each other. An exhaust piping device characterized by:

2. 2. The exhaust piping device according to claim 1, further comprising a cooling mechanism that introduces a coolant into the space within the hollow structure and cools the dielectric tube via the buffer member and the thin metal plate.

3. The high-frequency voltage is applied to the hollow structure, The high-frequency voltage is applied to the thin metal plate through the hollow structure, 3. The exhaust piping device according to claim 1, wherein the hollow structure and the thin metal plate are at substantially the same electrical potential.

4. a flange disposed on an end side of the dielectric tube and configured to fix the dielectric tube; The flange is grounded; 4. The exhaust piping device according to claim 1, wherein the plasma is generated by a potential difference between the high frequency electrode and the flange.

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