Exhaust pipe device

Abstract

An exhaust pipe device according to one embodiment includes: a dielectric pipe; a radio frequency electrode; and a plasma generation circuit. The exhaust pipe device is used as a part of an exhaust pipe arranged between a process chamber and a vacuum pump that exhausts gas in the process chamber. The radio frequency electrode includes a thin metal plate arranged on the outer peripheral side of the dielectric pipe, a buffer member arranged on the outer peripheral side of the thin metal plate, and a conductive hollow structure arranged on the outer peripheral side of the buffer member, and a radio frequency voltage is applied to the radio frequency electrode. The plasma generation circuit generates plasma in the dielectric pipe.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based upon and claims the benefit of priority from Japanese patent application No. 2021-191125 filed in Japan on November 25, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The embodiments described herein generally relate to exhaust pipe arrangements. Background Art

[0004] In a film forming apparatus represented by a chemical vapor deposition (CVD) apparatus, a raw material gas is introduced into a film forming chamber to form a desired film on a substrate disposed in the film forming chamber. The raw material gas remaining in the film forming chamber is discharged by a vacuum pump through an exhaust pipe. At this point, undesirable conditions already exist, such as the exhaust pipe being blocked by the deposition of products generated by the raw material gas in the exhaust pipe, and the vacuum pump being stopped by the deposition of products in the vacuum pump downstream of the exhaust pipe. A remote plasma source (RPS) device is used for cleaning to remove the deposits. However, since the RPS device generally focuses on cleaning the interior of the film forming chamber, the cleaning performance is not sufficient to clean the products deposited in the exhaust pipe far from the RPS device and the exhaust pipe near the vacuum pump.

[0005] A technique has also been disclosed for generating plasma within a conduit by applying an RF voltage to an RF electrode disposed on the outer periphery of an insulating material such as ceramic or quartz. This plasma removes unreacted gases and waste gases generated during ashing, etching, vapor deposition, cleaning, and nitriding processes. However, insufficient contact between the conduit and the RF electrode can lead to uneven plasma generation within the conduit. Summary of the Invention

[0006] According to one embodiment, an exhaust pipe device includes: a dielectric tube; a radio frequency electrode; and a plasma generation circuit. The exhaust pipe device serves as part of an exhaust pipe disposed between a processing chamber and a vacuum pump that exhausts gas from the processing chamber. The radio frequency electrode includes a thin metal plate disposed on the outer periphery of the dielectric tube, a buffer member disposed on the outer periphery of the thin metal plate, and a conductive hollow structure disposed on the outer periphery of the buffer member. An radio frequency voltage is applied to the radio frequency electrode. The plasma generation circuit generates plasma within the dielectric tube.

[0007] In addition, hereinafter, an embodiment provides an exhaust pipe device capable of generating plasma close to a uniform state and removing products deposited in an exhaust pipe near a vacuum pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1is a configuration diagram showing one example of the configuration of an exhaust system of a semiconductor manufacturing apparatus according to a first embodiment;

[0009] Figure 2 is a sectional view of one example of the exhaust pipe device according to the first embodiment when viewed from the front;

[0010] Figure 3 is a cross-sectional view of one example of the exhaust pipe device according to the first embodiment when viewed from above;

[0011] Figure 4 is a diagram showing one example of the configuration of a radio frequency electrode according to the first embodiment;

[0012] Figure 5 is a diagram showing an example of how to assemble the radio frequency electrode in the first embodiment;

[0013] Figure 6 is a plan view showing an example of a plasma generation state in Comparative Example 1 of the first embodiment;

[0014] Figure 7 is a plan view showing an example of a plasma generation state in the first embodiment;

[0015] Figure 8 is a graph for explaining the relationship between the inner tube temperature and the cleaning process time;

[0016] Figure 9 is a diagram showing one example of the layout of cooling pipes according to the first embodiment;

[0017] Figure 10 is a front view of an example of an exhaust pipe device according to Comparative Example 2 of the first embodiment;

[0018] Figure 11 is a sectional view of one example of the exhaust pipe device according to the second embodiment when viewed from the front; and

[0019] Figure 12 is a cross-sectional view of one example of the exhaust pipe device according to the third embodiment when viewed from the front. DETAILED DESCRIPTION

[0020] (First embodiment)

[0021] Figure 1 1 is a configuration diagram showing an example of the configuration of the exhaust system of the semiconductor manufacturing apparatus according to the first embodiment. Figure 1 In the example of FIG, a film forming apparatus, such as a chemical vapor deposition (CVD) apparatus 200, is shown as a semiconductor manufacturing apparatus. Figure 1In the example shown, a multi-chamber CVD apparatus 200 is configured with two film-forming chambers 202. In the CVD apparatus 200, semiconductor substrates 204 (204a, 204b) are placed within the film-forming chambers 202, which are controlled to a desired temperature. Films are then formed on these semiconductor substrates. A vacuum pump 400 is then used to evacuate the chambers 202 through the exhaust pipes 150 and 152, and a raw material gas is supplied to the chambers 202, which are controlled to a desired pressure by a pressure regulating valve 210. Within the chambers 202, the desired film is formed on the substrates 204 through a chemical reaction of the raw material gases. For example, a silane (SiH4)-based gas is introduced as the main raw material gas to form a silicon oxide film (SiO film) or a silicon nitride film (SiN film). Alternatively, for example, a tetraethoxysilane (TEOS) gas or the like is introduced as the main raw material gas to form a silicon oxide film (SiO film). As these films are formed, products generated by these raw material gases are deposited in the chambers 202 and the exhaust pipes 150 and 152. Therefore, in the film forming process cycle, a cleaning process is performed in addition to the film forming process.

[0022] In the cleaning process, a cleaning gas or a purge gas is supplied to a remote plasma source (RPS) device 300 disposed upstream of the film forming chamber 202, and fluorine (F) radicals are generated by plasma. Examples of cleaning gases include nitrogen trifluoride (NF3) gas. Examples of purge gases include argon (Ar) gas. Then, by supplying (diffusion) F radicals into the film forming chamber 202 and toward the exhaust pipe 150, the deposited product is cleaned. After the deposit is decomposed by cleaning, for example, silicon tetrafluoride (SiF4) is produced. Since silicon tetrafluoride (SiF4) has high volatility, silicon tetrafluoride is discharged from the vacuum pump 400 through the exhaust pipes 150 and 152.

[0023] However, it is difficult for F radicals to reach the portion of the exhaust pipes 150, 152 that is away from the film forming chamber 202. Therefore, the cleaning performance deteriorates. In particular, at a position close to the inlet port of the vacuum pump 400, the cleaning rate is low due to the low pressure. As a result, the inside of the exhaust pipes 150 and 152 may be clogged with deposited products. In addition, the gap between the rotor and the housing may be filled with products deposited in the vacuum pump 400, which leads to an overload state, and then the vacuum pump 400 may stop. Therefore, in the first embodiment, as shown in FIG. Figure 1 As shown, the exhaust pipe device 100 is arranged at a position closer to the inlet port of the vacuum pump 400 than the film forming chamber 202 .

[0024] exist Figure 1In the first embodiment, the exhaust pipe device 100 is used as a portion of the exhaust pipe, which includes exhaust pipes 150 and 152 arranged between the film forming chamber 202 (an example of a processing chamber) and the vacuum pump 400 that exhausts the interior of the film forming chamber 202. The exhaust pipe device 100 includes an outer tube 102, an inner tube 190 (dielectric tube) composed of a dielectric, and a plasma generation circuit 106. For example, the outer tube 102 is made of the same material as the conventional exhaust pipes 150 and 152. For example, a stainless steel material such as SUS 304 is used. However, from the perspective of corrosion resistance to the cleaning gas, SUS 316 steel is more preferably used as the material of the outer tube 102. In addition, for example, the outer tube 102 is made of the same size as the conventional exhaust pipes 150 and 152. However, the material and size are not limited to those described above. A tube larger than the exhaust pipes 150 and 152 may be used. Alternatively, a smaller tube may be used.

[0025] Flanges are provided at both ends of the inner pipe 190 and the outer pipe 102. One end thereof is connected to the exhaust pipe 150 having a flange of the same size, and the other end thereof is connected to the exhaust pipe 152 having a flange of the same size. Figure 1 , the clamps and the like for fixing the flange of the exhaust pipe device 100 and the flanges of the exhaust pipes 150 and 152 are not shown. In the following, this applies to each figure. In addition, sealing materials such as O-rings for connection with the exhaust pipes 150 and 152 are not shown. In the following, in each embodiment, the exhaust pipe 152 is clamped between the exhaust pipe device 100 and the vacuum pump 400, but is not limited to this configuration. The exhaust pipe device 100 can be directly configured at the inlet port of the vacuum pump 400. The inner tube 190 made of a dielectric is configured inside the outer tube 102. The plasma generation circuit 106 generates capacitively coupled plasma (CCP) inside the inner tube 190 made of a dielectric using electrodes to be described later that are configured on the outer peripheral side of the inner tube 190.

[0026] Figure 2 is a cross-sectional view of one example of the exhaust pipe device according to the first embodiment, viewed from the front. Figure 3 This is a cross-sectional view of an example of the exhaust pipe device according to the first embodiment, viewed from above. Figure 2 In FIG, the cross-sectional structure is the cross-sectional structure of the exhaust pipe device 100, and the cross-sectional structures of other components are not shown. In the following, the same applies to each cross-sectional view viewed from the front. Figure 2 and 3 In FIG, the exhaust pipe device 100 is formed into a double-pipe structure of an outer pipe 102 and an inner pipe 190 made of a dielectric and arranged inside the outer pipe 102. The inner pipe 190 is formed to have a shape similar to that of the outer pipe 102. Figure 2 and 3In the example of FIG, corresponding to the cylindrical outer tube 102 having a circular cross-section (ring shape), a cylindrical inner tube 190 having a circular cross-section (ring shape) similar to that of the outer tube 102 is used. Alternatively, corresponding to the cylindrical outer tube 102 having a rectangular cross-section, a cylindrical inner tube 190 having a rectangular cross-section similar to that of the outer tube 102 may be used.

[0027] Inner tube 190 is separated from the inner wall of outer tube 102 by space 36. The dielectric material forming inner tube 190 can be any material having a dielectric constant greater than that of air. Preferred materials for inner tube 190 include, for example, quartz, aluminum oxide (Al2O3), yttrium oxide (Y2O3), hafnium oxide (HfO2), zirconium oxide (ZrO2), magnesium oxide (MgO), and aluminum nitride (AlN). The thickness of inner tube 190 can be appropriately set as long as it does not impair exhaust performance.

[0028] RF electrode 104 is disposed inside outer tube 102 and on the outer periphery of inner tube 190. RF electrode 104 includes a thin metal plate 50 disposed on the outer periphery of inner tube 190, which serves as a dielectric tube; a buffer member 52 disposed on the outer periphery of thin metal plate 50; and a conductive hollow structure 54 disposed on the outer periphery of buffer member 52. Thin metal plate 50 and hollow structure 54 are configured to have electrical conductivity.

[0029] When the RF electrode 104 is disposed on the outer peripheral side of the inner tube 190, the RF electrode 104 is formed into a shape corresponding to the outer peripheral shape of the inner tube 190. For example, a cylindrical (ring-shaped) RF electrode 104 having the same type of circular cross section is used for the cylindrical (ring-shaped) inner tube 190 having a circular cross section. Figure 2 As shown, the length of the RF electrode 104 is shorter than the length of the inner tube 190. Figure 2 As shown in the example of FIG, the radio frequency electrode 104 is arranged at the center in the height direction with a gap left between the upper end side and the lower end side of the inner tube 190.

[0030] The flange 19 is arranged on the end side of the inner tube 190. Figure 2 In the example shown, piping flanges 19 are provided at both ends of the inner tube 190. The flange 19 located upstream in the gas flow direction is fixed to the flange of the exhaust pipe 150. The flange 19 located downstream in the gas flow direction is fixed to the flange of the exhaust pipe 152. For example, the two flanges 19 can be made of the same material as that used for the conventional exhaust pipes 150 and 152. For example, a stainless steel material such as SUS 304 can be used. However, from the perspective of corrosion resistance to clean gas, SUS 316 steel is more preferably used as the material for the flanges 19.

[0031] In the first embodiment, as Figure 2As shown, the space between outer tube 102 and inner tube 190 is isolated from the ambient atmosphere and the space within inner tube 190 by sealing mechanisms 16 disposed at the upper and lower ends of inner tube 190 and outer tube 102. These sealing mechanisms 16 cover the outer circumference of inner tube 190. For example, sealing mechanisms 16 are preferably constructed as follows. Each sealing mechanism 16 includes a protrusion 10, an O-ring retainer 11, an O-ring 12, and an O-ring 14. Protrusions 10 are annularly disposed on the surfaces of corresponding flanges 19 at both ends of inner tube 190 and extend from the surfaces of corresponding flanges 19 toward RF electrode 104 on the outside of inner tube 190. O-rings 14, located closer (upstream) to exhaust pipe 150, are disposed between the flange surface of outer tube 102 (upstream) closer to exhaust pipe 150 and flange 19. O-ring 14 is disposed between the flange surface of outer tube 102 (on the downstream side) closer to exhaust pipe 152 and flange 19. In this case, on the upstream side of exhaust pipe assembly 100, the flange of outer tube 102 and the flange of tube 150 are preferably clamped together with flange 19 interposed therebetween. On the downstream side of exhaust pipe assembly 100, the flange of outer tube 102 and the flange of tube 152 are preferably clamped together with flange 19 interposed therebetween. O-ring 14 isolates the atmosphere within outer tube 102 from the ambient atmosphere.

[0032] Each O-ring 12 is arranged in a state of being squeezed between the outer peripheral surface of the end portion of the inner tube 190 and the inner peripheral surface of the protrusion 10. Therefore, the protrusion 10 is formed to have an inner diameter larger than the outer diameter of the inner tube 190 and an outer diameter smaller than the inner diameter of the outer tube 102. Each O-ring 12 is squeezed by the O-ring retaining ring 11. The O-ring retaining ring 11 may be formed as one member, or may be formed as a combination of two members, that is, an annular member arranged between the outer peripheral surface of the end portion of the inner tube 190 and the inner peripheral surface of the protrusion 10, and an annular member as shown in FIG. Figure 2 As a result, the atmosphere within the inner tube 190 is isolated from the space 36 between the outer tube 102 and the inner tube 190 via the O-ring 12 .

[0033] In the first embodiment, by forming a sealed double-tube structure of outer tube 102 and inner tube 190 as described above, even if inner tube 190, which is made of a dielectric material, is damaged, the gas flowing through the exhaust pipe can be prevented from leaking into the ambient atmosphere. Similarly, the intrusion (inflow) of ambient air into the exhaust pipe can be prevented. Even if the space between outer tube 102 and inner tube 190 is controlled to atmospheric pressure, the inflow of ambient air to the extent that the vacuum pump 400 malfunctions can be prevented because the volume between outer tube 102 and inner tube 190 is very small.

[0034] exist Figure 2 and 3In the example of FIG, the outer tube 102 is arranged outside the inner tube 190, but the double tube structure is not limited thereto.

[0035] Figure 4 1 is a diagram showing an example of the configuration of the radio frequency electrode according to the first embodiment. As described above, the radio frequency electrode 104 includes the thin metal plate 50 , the buffer member 52 , and the hollow structure 54 .

[0036] The thin metal plate 50 is thinner than the hollow structure 54. Therefore, the thin metal plate can be bent more easily than the hollow structure 54. Specifically, the thin metal plate 50 is formed by bending the thin metal plate into a ring shape, for example, a circle. For example, a thin plate with a thickness of about 0.1 mm to 3 mm is used. Flanges folded outward are formed at both ends of the thin plate in the bending direction. Screw holes are formed in the flanges. Figure 4 In the example, two screw holes are formed in the upper and lower parts. As the material of the thin metal plate 50, a soft material with low resistivity is suitable. For example, copper (Cu) or aluminum (Al) is preferably used. Due to the low resistivity, the entire surface can be easily brought to the same potential as the hollow structure 54 even if the thickness is small. In addition, due to its softness, it can be easily bent. By using, for example, a copper material that is softer than a stainless steel material, it can be easily bent even if the thickness is, for example, 3 mm.

[0037] The hollow structure 54 is formed as a combination of a half-hollow structure 54-1 and a half-hollow structure 54-2, obtained by dividing the circumference of a cylindrical shape into equal parts. A cavity 34 is formed in the hollow structure 54. Specifically, the cavity 34 is formed in each of the half-hollow structure 54-1 and the half-hollow structure 54-2. The cavity 34 is appropriately formed throughout the entire hollow structure 54. The hollow structure 54 is formed from a conductive material. Furthermore, as will be described later, copper with high conductivity is used to allow cooling water to flow into the cavity 34. Alternatively, aluminum or steel such as SUS 304 or SUS 316 can be used. The hollow structure 54 guides the radio frequency potential applied from the lead terminal 111 to the thin metal plate 50 and serves as a heat exchanger as part of the cooling mechanism. Flanges for mounting are formed at the half ends of the half-hollow structure 54-1 and the half-hollow structure 54-2. Screw holes are formed in the flange. Figure 4 In the example of FIG, two screw holes are formed, one on the upper side and the other on the lower side. The screw holes of the semi-hollow structure 54 - 1 and the semi-hollow structure 54 - 2 are formed to be staggered from the screw holes of the thin metal plate 50 .

[0038] Cushioning member 52 is sandwiched between thin metal plate 50 and hollow structure 54, serving as a buffer between them. Cushioning member 52 is formed by dividing the cylindrical circumference into equal parts, resulting in a combination of half-cushioning member 52-1 and half-cushioning member 52-2. Cushioning member 52 is ideally made of a material with high thermal conductivity to efficiently transfer heat from inner tube 190, which serves as the dielectric tube, to hollow structure 54. The thermal conductivity is preferably approximately 1 to 10 W / m·K, for example. Furthermore, heat resistance sufficient to withstand the heat generated by the dielectric is required. For example, heat resistance of approximately 100 to 150°C is preferred. As a material that meets these requirements, a sheet of organosilicon polymer or silicone polymer is preferably used as cushioning member 52. Alternatively, a silicone gel material can be appropriately applied to the inner surface of hollow structure 54 as cushioning member 52. The thickness of cushioning member 52 is preferably approximately 0.1 to 0.5 mm, for example.

[0039] Figure 5 1 is a diagram illustrating an example of a method for assembling the radio frequency electrode in the first embodiment. First, a thin metal plate 50 is attached to the outer periphery of the inner tube 190. By inserting screws 56 into screw holes in the flanges and tightening the flanges so that they are close together, the thin metal plate 50 can be brought into close contact with the outer periphery of the inner tube 190.

[0040] Next, the thin metal plate 50 is installed from the outer peripheral side so as to be sandwiched between the semi-hollow structure 54-1 with the semi-buffer member 52-1 arranged on the inner surface and the semi-hollow structure 54-2 with the semi-buffer member 52-2 arranged on the inner surface. Then, the hollow structure 54 is attached to the outer peripheral side of the thin metal plate 50 via the buffer member 52 by inserting screws 58 into the screw holes of the flanges between the semi-hollow structure 54-1 and the semi-hollow structure 54-2 and tightening the flanges so that they are close to each other. At this time, as shown in FIG. Figure 3 As shown, assembly is performed so that the end of the screw 56 that contacts the thin metal plate 50 contacts the hollow structure 54. As a result, the hollow structure 54 can be electrically connected to the thin metal plate 50. Note that the semi-hollow structure 54-1 and the semi-hollow structure 54-2 are electrically connected to each other via the screw 58.

[0041] Although the case of electrically connecting the hollow structure 54 to the thin metal plate 50 using screws 56 has been described, the present invention is not limited thereto. For example, conductive nanoparticles may be added to the organic silicon polymer / silicone polymer used as the buffer member 52. As a result, the buffer member 52 can be configured to electrically connect the hollow structure 54 to the thin metal plate 50.

[0042] exist Figure 2 and 3In the example shown in FIG. 1 , a radio frequency (RF) electric field is applied to the RF electrode 104 by the plasma generation circuit 106. Specifically, a lead terminal 111 (an example of an RF lead terminal) is introduced into the outer tube 102 from a lead terminal port 105 connected to the outer circumferential surface of the outer tube 102 and connected to the RF electrode 104. In the first embodiment, the flange 19 serves as a ground electrode. The outer tube 102 is also grounded.

[0043] Then, the plasma generation circuit 106 generates plasma within the inner tube 190 by utilizing capacitive coupling between the RF electrode 104 and the ground electrode. Specifically, with the flange 19 grounded (applied to ground potential) as the ground electrode, the plasma generation circuit 106 applies a radio frequency (RF) voltage to the hollow structure 54 of the RF electrode 104 via the lead terminal 111. As a result, the thin metal plate 50, electrically connected to the hollow structure 54, has the same potential as the hollow structure 54. Therefore, the potential difference between the RF electrode 104 (thin metal plate 50) and the flange 19 generates a capacitively coupled plasma (CCP) within the dielectric inner tube 190. Furthermore, since a cleaning gas, such as the aforementioned NF3 gas, is supplied upstream during the cleaning process, the remaining cleaning gas generates plasma-derived F radicals within the inner tube 190. These F radicals then remove products deposited within the inner tube 190. Consequently, high cleaning performance can be achieved within the exhaust pipe.

[0044] Afterward, for example, SiF4 generated by the decomposition of the deposit by F radicals has high volatility and is therefore exhausted by the vacuum pump 400 through the exhaust pipe 152. Furthermore, a portion of the radicals generated in the exhaust pipe device 100 enters the vacuum pump 400 through the exhaust pipe 152 and cleans the products deposited in the vacuum pump 400. As a result, the amount of products deposited in the vacuum pump 400 can be reduced. For example, while the consumption within the inner tube 190 is low, F radicals generated by the plasma at a portion of the inner wall surface at the lower end of the inner tube 190 can be allowed to enter the vacuum pump 400.

[0045] Figure 6 : is a top view showing an example of a plasma generation state in Comparative Example 1 of the first embodiment. Figure 6 In the comparative example 1 shown, Figure 2 and 3In the example of , the hollow structure 354 is directly arranged on the outer periphery of the inner tube 190 without arranging the thin metal plate 50 and the buffer member 52. In Comparative Example 1, when the hollow structure 354 is installed around the inner tube 190, a contact portion and a non-contact portion are generated between the inner peripheral surface of the hollow structure 354 and the outer peripheral surface of the inner tube 190. When a radio frequency voltage is applied to the hollow structure 354, the radio frequency electric field is strong and the plasma emission is strong at the contact portion, while the radio frequency electric field is weak and the plasma emission is weak at the non-contact portion. As described above, in the configuration of Comparative Example 1, the plasma does not diffuse to the non-contact portion, and the plasma generation becomes uneven. As a result, the cleaning effect is deteriorated.

[0046] Figure 7 1 is a top view showing an example of a plasma generation state in the first embodiment. In the first embodiment, since the thin metal plate 50, which is thinner than the hollow structure 54, can be brought into close contact with the inner tube 190, it is possible to prevent the generation of a non-contact portion between the inner circumference of the thin metal plate 50 and the outer circumference of the inner tube 190. When a radio frequency voltage is applied to the hollow structure 54, the entire conductive thin metal plate 50 can be electrically set to approximately the same potential as the hollow structure 54. As a result, as shown in FIG. Figure 7 As shown, it can be expected that uniform plasma will be generated in the circumferential direction without any weak emission areas.

[0047] Here, in the above example, the double-tube structure is configured to prevent leakage and ambient air intrusion due to dielectric damage to the inner tube 190. Causes of damage to the inner tube 190 made of dielectric may include temperature increase of the inner tube 190.

[0048] like Figure 8 This is a graph for explaining the relationship between the inner tube temperature and the cleaning process time. Figure 8 In the figure, the vertical axis represents the temperature of the inner tube in the exhaust pipe, and the horizontal axis represents the continuous treatment time of the exhaust pipe during the cleaning process. Figure 8 The graph shown in the example of FIG shows an example of a case where the inner tube 190 is used without cooling. During the cleaning process, an RF voltage is applied to the RF electrode 104. Thus, the temperature of the RF electrode 104 increases. Accordingly, the temperature of the inner tube 190, which is a dielectric tube in which plasma is generated, increases. Figure 8 As shown in the graph of FIG, if the process is continued without cooling, the temperature increases as the cleaning process time increases, and the inner tube 190 may eventually be damaged. In order to suppress damage to the inner tube 190 composed of a dielectric due to the temperature increase, it is desirable to cool the inner tube 190. Therefore, in the first embodiment, a configuration that can suppress the temperature increase of the inner tube 190 will be described below.

[0049] In the first embodiment, a cooling mechanism is provided that guides cooling water (an example of a refrigerant) into the space 34 in the hollow structure 54 via the buffer member 52 and the thin metal plate 50 to cool the inner tube 190 (dielectric tube).

[0050] Figure 9 : is a diagram showing an example of the layout of the cooling pipe according to the first embodiment. Figure 2 and 3 As shown in the example of , the cavity 34 is formed in the hollow structure 54. The cavity 34 is appropriately formed in the entire hollow structure 54. As described above, the hollow structure 54 is formed as a combination of a semi-hollow structure 54-1 and a semi-hollow structure 54-2. Therefore, the cooling pipe 30 is arranged below the cavity 34 in the semi-hollow structure 54-1. The cooling pipe 32 is arranged above the cavity 34 in the semi-hollow structure 54-2. A cooling pipe 37 is arranged between the upper part of the cavity 34 in the semi-hollow structure 54-1 and the lower part of the cavity 34 in the semi-hollow structure 54-2. In order to facilitate the assembly of the semi-hollow structure 54-1 and the semi-hollow structure 54-2, it is preferred to use a flexible pipe as the cooling pipe 37. However, it is not limited to this. After the semi-hollow structure 54-1 and the semi-hollow structure 54-2 are assembled, a fixed cooling pipe 37 that is difficult to bend freely can be installed.

[0051] exist Figure 2 In the example shown, cavity 31 is formed in flange 19 located on the exhaust pipe 152 side (downstream side). Similarly, cavity 33 is formed in flange 19 closer to exhaust pipe 150 (upstream). Cavities 31 and 33 can be formed in the entire or partial inner side of the corresponding flange 19. For example, each cavity can be formed to have an L-shape, including two linearly extending cylindrical cavities connected to each other. Cavity 31 has an inflow port formed in the side of flange 19, and an outflow port formed on the side of space 36 between outer tube 102 and inner tube 190. Cavity 33 has an inflow port formed on the side of space 36 between outer tube 102 and inner tube 190, and an outflow port formed in the side of flange 19. Cooling pipe 30 connects the outflow port of cavity 31 and the lower part of cavity 34 in hollow structure 54 (e.g., semi-hollow structure 54-1). Cooling pipe 37 connects the upper portion of cavity 34 of semi-hollow structure 54-1 to the lower portion of cavity 34 of semi-hollow structure 54-2. Furthermore, cooling pipe 32 connects the upper portion of cavity 34 in semi-hollow structure 54-2 to the inlet port of cavity 33. Flange 19 in which cavity 31 is formed, flange 19 in which cavity 33 is formed, cooling pipes 30, 32, and 37, and hollow structure 54 in which cavity 34 is formed constitute part of the cooling mechanism.

[0052] The cooling water supplied to the side of the flange 19 located on the exhaust pipe 152 side (downstream side) passes through the cavity 31 in the flange 19 located on the exhaust pipe 152 side (downstream side), passes through the cooling pipe 30, and moves to the lower portion of the cavity 34 in the semi-hollow structure 54-1. The cooling water supplied to the lower portion of the cavity 34 in the semi-hollow structure 54-1 accumulates in the cavity 34 from the lower portion to the upper portion. The cooling water overflowing from the upper portion of the cavity 34 in the semi-hollow structure 54-1 is supplied to the lower portion of the cavity 34 in the semi-hollow structure 54-2 via the cooling pipe 37. The cooling water supplied to the lower portion of the cavity 34 in the semi-hollow structure 54-2 accumulates in the cavity 34 from the lower portion to the upper portion. The cooling water overflowing from the upper portion of the cavity 34 in the semi-hollow structure 54-2 passes through the cooling pipe 32 and moves to the cavity 33 in the flange 19 located on the exhaust pipe 150 side (upstream side). The water then passes through the cavity 33 in the flange 19 and out of the outflow port on the side of the flange 19 .

[0053] While cooling water flows, the plasma generation circuit 106 generates plasma within the inner tube 190 using the RF electrode 104. The plasma generation circuit 106 applies a radio frequency voltage to the RF electrode 104. At this point, the cooling water flowing through the hollow structure 54 cools the inner tube 190, a dielectric tube heated by the plasma generated within it, and the space 36 between the inner tube 190 and the outer tube 102. As a result, the RF voltage is applied, and the heated RF electrode 104 is directly cooled. In the first embodiment, the buffer member 52 with high thermal conductivity is sandwiched between the hollow structure 54 and the metal film 50, ensuring close contact without any gaps. Therefore, by directly cooling the hollow structure 54, the metal film 50 can be effectively cooled. Furthermore, the inner tube 190, which is in close contact with the inner circumference of the metal film 50, can be effectively cooled. Consequently, the temperature rise of the inner tube 190 can be suppressed.

[0054] Figure 10 : is a front view of an example of an exhaust pipe device according to Comparative Example 2 of the first embodiment. Figure 10 Comparative Example 2 shows a case where an RF electrode 304 is disposed in the space between the outer tube 302 and the dielectric tube 390, located on the outer circumference of the dielectric tube 390. Tube flanges 319, serving as ground electrodes, are disposed at both ends of the dielectric tube 390. Capacitively coupled plasma (CCP) is generated by applying an RF voltage to the RF electrode 304 using the flanges 319 as ground electrodes. In this configuration, the flanges 319 and the RF electrode 304 are capacitively coupled to induce discharge.

[0055] exist Figure 10In the example of FIG, it is also conceivable to cool the outer peripheral surface of the outer tube 302 disposed on the outer peripheral side of the dielectric tube 390 and the RF electrode 304 by supplying cooling water. However, even if the outer side of the outer tube 302 is cooled, it is difficult to sufficiently cool the space between the outer tube 302 and the dielectric tube 390 through the outer tube 302. Therefore, cooling the outer tube 302 may cause the dielectric tube 390 to heat up, thereby damaging the dielectric tube 390.

[0056] On the other hand, in the first embodiment, since the outer peripheral surface of the inner tube 190 is directly cooled by the RF electrode 104, the temperature increase of the inner tube 190 can be suppressed compared to the case where the cooling is carried out from the outside of the outer tube 102. In the first embodiment, when a double-tube structure in which the outer tube is arranged outside the inner tube is not formed, the hollow structure 54 having the cavity 34 formed therein is cooled as part of the cooling mechanism, thereby appropriately suppressing the temperature increase of the inner tube 190.

[0057] As described above, according to the first embodiment, the generation of plasma can be made close to a uniform state, and products deposited in the exhaust pipe near the vacuum pump can be removed.

[0058] (Second embodiment)

[0059] exist Figure 10 In the configuration of Comparative Example 2, flange 319 and RF electrode 304 are capacitively coupled to induce discharge. Discharge can occur not only inside dielectric tube 390 but also outside of it, for example, on the side where atmospheric pressure is set. Therefore, it is desirable to increase the distance L3 between flange 319 (ground electrode) and RF electrode 304 to a level where discharge does not occur on the atmospheric pressure side. When the distance L3 between flange 319 (ground electrode) and RF electrode 304 is large, the increased gas flow rate and pressure within dielectric tube 390 make plasma generation difficult, leading to unstable discharge. On the other hand, by reducing the electrode dimension of RF electrode 304 in the gas flow direction to increase the voltage or / and reducing the distance L3 between flange 319 (ground electrode) and RF electrode 304, plasma generation is facilitated, but abnormal discharge (arcing) is more likely to occur on the atmospheric pressure side.

[0060] Therefore, in the second embodiment, the ground electrode is arranged so that the distance from the radio frequency electrode 104 is smaller inside the inner tube 190 than outside.

[0061] Figure 11 This is a cross-sectional view of an example of the exhaust pipe device according to the second embodiment when viewed from the front. A cross-sectional view of an example of the exhaust pipe device according to the second embodiment when viewed from above is not provided. In addition to the annular protrusion 18 extending from the surface of the flange 19 toward the RF electrode 104 on the inner side of the inner tube 190, Figure 11and Figure 2 same.

[0062] Each protrusion 18 is made of a conductive material and serves as part of the ground electrode. For example, each protrusion 18 is formed integrally with the flange 19 to which it is connected. Alternatively, each protrusion 18 may be formed separately from the flange 19, as long as it is electrically connected to the flange 19. Furthermore, when each O-ring retaining ring 11 is made of a conductive material, each O-ring retaining ring 11 serves as part of the ground electrode by contacting the protrusion 10.

[0063] exist Figure 11 In the example shown, because the tip of protrusion 10 or the exposed surface of O-ring 11 on the RF electrode 104 side is closest to RF electrode 104 located outside inner tube 190, protrusion 18 is formed so that the distance L1 between the tip of protrusion 18 and RF electrode 104 is smaller than the distance L2 between the tip of protrusion 10 or the exposed surface of O-ring 11 on the RF electrode 104 side located outside inner tube 190 and RF electrode 104. In the absence of protrusion 10, protrusion 18 is configured so that the distance L1 between the tip of protrusion 18 and RF electrode 104 is smaller than the distance between the flange surface located outside inner tube 190 and RF electrode 104. Consequently, when an RF voltage is applied to RF electrode 104, discharge occurs first between protrusion 18 and RF electrode 104. Therefore, for example, plasma based on capacitive coupling can be generated within inner tube 190 without applying a voltage that causes abnormal discharge (arcing) on ​​the atmospheric pressure side. Reducing the distance between the vacuum-side electrodes can further improve the ignitability and stability of the plasma and also suppress arc discharge.

[0064] Note that ideally, the protrusion 18 is arranged such that the distance L1 between the distal end of the protrusion 18 and the RF electrode 104 is smaller than the distance between the grounded outer tube 102 and the RF electrode 104 .

[0065] The rest of the configurations Figure 2 The middle configuration is similar.

[0066] As described above, according to the second embodiment, in addition to the same effects as those of the first embodiment, products deposited in the exhaust pipe near the vacuum pump can be further removed while avoiding abnormal discharge such as arc discharge.

[0067] (Third embodiment)

[0068] In the above embodiments, the inner tube 190 in close contact with the RF electrode 104 is directly cooled by flowing cooling water into the cavity 34 of the hollow structure 54. A third embodiment will be described in which the cooling mechanism cools the space 36 between the inner tube 190 and the outer tube 102.

[0069] Figure 12 1 is a cross-sectional view of an example of the exhaust pipe device according to the third embodiment as viewed from the front. A cross-sectional view of an example of the exhaust pipe device according to the third embodiment as viewed from above is not provided. In addition to further providing a gas introduction port 41, a valve 40 (or a check valve 42), a gas discharge port 43, and a valve 44 (or a check valve 46), Figure 12 and Figure 11 The same. The cooling mechanism in the third embodiment guides the cooling gas (another example of refrigerant) into the space 36 between the inner tube 190 and the outer tube 102 from the gas introduction port 41 arranged below the outer peripheral surface of the outer tube 102 via the valve 40 (or the check valve 42). The cooling gas is then discharged to the outside from the gas discharge port 43 provided in the upper portion of the outer peripheral surface of the outer tube 102 via the valve 44 (or the check valve 46). By allowing the cooling gas to flow into the space 36 between the inner tube 190 and the outer tube 102, the inner tube 190 and the space 36 located between the inner tube 190 and the outer tube 102 are cooled. The inner tube 190 is a dielectric tube that heats up due to the plasma generated inside. By cooling the inner tube 190 with the cooling gas, the effect of suppressing damage to the inner tube 190 can be further improved. For example, air is used as the cooling gas.

[0070] Cooling gas is introduced into the space 36 between the inner tube 190 and the outer tube 102 at a pressure higher than atmospheric pressure. Therefore, the pressure in the space 36 between the inner tube 190 and the outer tube 102 is controlled to be higher than both the pressure inside the inner tube 190 and atmospheric pressure. The pressure in the space 36 between the inner tube 190 and the outer tube 102 is measured by a pressure sensor 48 via a vent 47 disposed on the outer circumference of the outer tube 102, monitoring pressure fluctuations within the space 36. If the inner tube 190, a dielectric tube heated by plasma generation, is damaged, vacuum breakdown may occur when a large amount of cooling gas flows into the vacuum side. Consequently, the pressure sensor 48 detects damage to the inner tube 190.

[0071] Specifically, when pressure sensor 48 detects a pressure drop, control is executed to close valves 40 and 44. As a result, the flow of cooling gas into the exhaust line can be minimized. When a check valve 42 is used instead of valve 40, the check valve 42 has a cracking pressure set so that it closes when the pressure difference between the primary and secondary pressures is greater than 0.1 MPa and less than the cooling gas supply pressure. When the supply source stops supplying cooling gas, the primary pressure (the primary side of the check valve) is equal to atmospheric pressure, the secondary pressure (inside outer tube 102) is equal to or less than atmospheric pressure (due to damage, the pressure has dropped below atmospheric pressure), and the pressure difference is equal to or less than 0.1 MPa. Therefore, when the relationship 0.1 MPa < cracking pressure < supply pressure holds, cooling gas does not flow. Therefore, if the supply source stops supplying cooling gas in response to detecting damage to inner tube 190, ambient air can be prevented from flowing into outer tube 102 even when the primary side is open to ambient air. When the check valve 46 is used instead of the valve 44 , damage to the inner tube 190 causes the primary pressure to fall below the secondary pressure, thereby blocking the flow path and preventing ambient air from flowing into the outer tube 102 .

[0072] The rest of the configurations Figure 11 The configuration is similar to .

[0073] 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.

[0074] The embodiments have been described 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 pipe device can also be applied to semiconductor manufacturing equipment other than film forming equipment such as etching equipment.

[0075] Furthermore, any exhaust pipe device that includes the elements of the present invention and can be implemented by a person skilled in the art through appropriate design changes falls within the scope of the present invention.

[0076] Although certain embodiments have been described, these embodiments have been presented by way of example only and are not intended to limit the scope of the invention. Indeed, the novel methods and apparatus described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions, or changes in form may be made to the methods and apparatus described herein without departing from the spirit of the invention. The appended claims and their equivalents are intended to cover such forms or modifications as fall within the scope and spirit of the invention.

Claims

1. An exhaust pipe device used as a part of an exhaust pipe arranged between a processing chamber and a vacuum pump for exhausting gas in the processing chamber, the exhaust pipe device comprising: Dielectric tube; a radio frequency electrode including a thin metal plate disposed on an outer peripheral side of the dielectric tube, a buffer member disposed on an outer peripheral side of the thin metal plate, and a conductive hollow structure disposed on an outer peripheral side of the buffer member and to which a radio frequency voltage is applied; and a plasma generating circuit for generating plasma within the dielectric tube, The thin metal plate is arranged on the outer peripheral side of the dielectric tube in close contact with the dielectric tube. 2 . The exhaust pipe device according to claim 1 , further comprising a first cooling mechanism configured to introduce a first refrigerant into the space in the hollow structure and cool the dielectric pipe via the buffer member and the thin metal plate.

3. The exhaust pipe device according to claim 2, wherein: Cooling water is used as the first refrigerant.

4. The exhaust pipe device according to claim 1, wherein: The thickness of the thin metal plate is thinner than that of the hollow structure.

5. The exhaust pipe arrangement according to claim 1, wherein applying a radio frequency voltage to the hollow structure, applying a radio frequency voltage to the thin metal plate via the hollow structure, and The hollow structure and the thin metal plate have the same potential.

6. The exhaust pipe arrangement according to claim 1, further comprising: An outer tube disposed outside the radio frequency electrode; and A second cooling mechanism is configured to guide a second refrigerant to a space between the dielectric tube and the outer tube and cool the dielectric tube and the space between the dielectric tube and the outer tube.

7. The exhaust pipe device according to claim 6, wherein: A cooling gas is used as the second refrigerant.

8. The exhaust pipe device according to claim 7, wherein: The cooling gas is introduced at a pressure above atmospheric pressure. 9 . The exhaust pipe arrangement of claim 6 , further comprising a pressure sensor configured to measure a pressure within a space between the dielectric tube and the outer tube.

10. The exhaust pipe arrangement according to claim 1, wherein The hollow structure includes one half hollow structure and another half hollow structure obtained by dividing the perimeter of the cylindrical shape into equal parts, and The hollow structure is formed as a combination of the one half hollow structure and the other half hollow structure.

11. The exhaust pipe device according to claim 10, wherein: A cavity is formed in each of the one half hollow structure and the other half hollow structure.

12. The exhaust pipe device according to claim 11, further comprising a first cooling mechanism configured to guide a first refrigerant into a space in the hollow structure and cool the dielectric pipe via the buffer member and the thin metal plate, wherein The first cooling mechanism includes a pipe configured to connect the cavity of the one half hollow structure and the cavity of the other half hollow structure.

13. The exhaust pipe device according to claim 10, wherein: The one half hollow structure is electrically connected to the other half hollow structure.

14. The exhaust pipe device according to claim 1, wherein: The buffer member includes one half buffer member and another half buffer member obtained by equally dividing the circumference of the cylindrical shape, and The cushioning member is formed as a combination of the one cushioning member half and the other cushioning member half.

15. The exhaust pipe device according to claim 14, in, The buffer member is arranged to be in close contact with the thin metal plate, wherein the thin metal plate is sandwiched by the one half buffer member and the other half buffer member.

16. The exhaust pipe arrangement according to claim 14, wherein The hollow structure includes one half hollow structure obtained by dividing the perimeter of the cylindrical shape into equal parts and the other half hollow structure, The one half buffer member is arranged on the inner surface side of the one half hollow structure, and The other half of the buffer member is arranged on the inner surface side of the other half of the hollow structure.

17. The exhaust pipe arrangement according to claim 1, further comprising: An outer tube disposed outside the radio frequency electrode; and a guide terminal which is guided from the outside of the outer tube to the inside and connected to the radio frequency electrode, wherein A radio frequency voltage is applied to the hollow structure through the lead terminal.

18. The exhaust pipe device according to claim 1, further comprising a flange disposed on an end side of the dielectric pipe and configured to fix the dielectric pipe, wherein The flange is grounded, and The plasma is generated by a potential difference between the RF electrode and the flange. 19 . The exhaust pipe device according to claim 18 , further comprising an annular protrusion disposed at an inner side of the dielectric tube to extend from the flange toward the RF electrode.

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