Plasma source

Abstract

The present invention provides an inductively coupled plasma source having a simple structure and an antenna cooling mechanism capable of suppressing the cost of the device. The plasma source (10) is a device for generating plasma in a vacuum container (21), and comprises a frame (antenna fixing frame (12)) provided on a wall (211) of the vacuum container (21), and a planar antenna (11) fixed in the frame. Since the antenna (11) is surrounded by the frame, the heat generated by the antenna (11) flows from its periphery to the frame, and then flows from the frame to the vacuum container, thereby efficiently cooling the device. Therefore, there is no need to use a liquid or gas refrigerant, which simplifies the structure, and no refrigerant temperature management device or circulation device is required, thereby suppressing the cost of the device.

Description

Technical Field

[0001] The present invention relates to an inductively coupled plasma source. Background Art

[0002] In an inductively coupled plasma source, after gas is introduced into a space where plasma is generated, a high-frequency current is passed through an antenna positioned near or within the space, generating a high-frequency electromagnetic field in the space. This dissociates the gas molecules into cations and electrons, generating plasma. At this time, the high-frequency current flowing through the antenna generates Joule heat, necessitating cooling of the antenna. Patent Document 1 describes the use of a conductive tube as an antenna, through which a liquid or gas refrigerant is passed through the tube, thereby cooling the antenna. The antenna is mounted to a metal (e.g., stainless steel) cover member via a feedthrough member, and the cover member is secured to the wall in a manner that blocks an opening provided in the wall of the vacuum container, thereby being mounted to the vacuum container.

[0003] [Prior Art Literature]

[0004] [Patent Document]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-212105 Summary of the Invention

[0006] [Problems to be Solved by the Invention]

[0007] The plasma source described in Patent Document 1 requires connecting electrodes for introducing high-frequency current to both ends of an antenna, or conductive tube, and connecting another tube (separate from the antenna) for introducing a liquid or gaseous refrigerant into the tube, resulting in a complex structure. Furthermore, a device for controlling the temperature of the refrigerant, or a circulation device if the refrigerant is to be circulated, is required, increasing the cost of the equipment.

[0008] An object of the present invention is to provide an inductively coupled plasma source having an antenna cooling mechanism that has a simple structure and can reduce the cost required for the device.

[0009] [Technical means to solve the problem]

[0010] The plasma source of the present invention, which has been developed to solve the above-mentioned problems, is a device for generating plasma in a vacuum container, and includes:

[0011] a) a frame provided on the wall of the vacuum container, and

[0012] b) A planar antenna fixed in the frame.

[0013] In the plasma source of the present invention, heat generated by a planar antenna is transferred to a heat bath, or vacuum chamber, via a frame to which the antenna is secured, thereby cooling the antenna. Because the planar antenna is surrounded by the frame, heat generated by the antenna flows from its periphery to the frame, and then from the frame to the vacuum chamber, resulting in efficient cooling. This eliminates the need for liquid or gaseous refrigerants, simplifying the structure. Furthermore, there is no need for refrigerant temperature management or circulation equipment, thus reducing the cost of the device.

[0014] In conventional plasma processing equipment, the vacuum chamber is made of a large metal body, so it is very likely that the heat generated by the antenna will be absorbed by this large metal body (heat bath). This can also reduce heat conduction to the power supply side that supplies current to the antenna.

[0015] As for the material of the frame, metal is preferably used due to its high thermal conductivity. Alternatively, a material other than metal with high thermal conductivity, such as aluminum nitride (AlN), may be used.

[0016] In the plasma source of the present invention, the frame and antenna can be configured as a cover member disposed to seal an opening in the vacuum vessel. Alternatively, the frame and antenna can also serve as the cover member for the opening. Thus, since the planar antenna is disposed within the opening of the vacuum vessel, heat generated by the antenna is not only conducted to the vacuum vessel via the frame but also dissipated from the antenna surface to the outside of the vacuum vessel. This allows for more efficient cooling of the antenna.

[0017] When the frame and antenna are disposed within the cover member, a dielectric window is preferably further provided. This dielectric window is a dielectric plate disposed on the opening side of the antenna. This protects the antenna from the plasma within the vacuum vessel. While the dielectric window receives heat from the plasma, in the present invention, this heat can also be discharged to the vacuum vessel via the antenna and frame. To minimize the loss of strength in generating a high-frequency electromagnetic field within the vacuum vessel, the dielectric window is preferably thin, for example, 5 mm or less.

[0018] When a dielectric window is disposed on the opening side of the antenna, it is preferable to further include a vacuum seal disposed between the wall surrounding the opening and the dielectric window.

[0019] Furthermore, when a dielectric window is positioned on the opening side of the antenna, it is preferable to further fill the gap between the antenna and the dielectric window with a dielectric adhesive. This improves the adhesion of the dielectric window compared to direct contact with the antenna. Because the dielectric window is in contact with the adhesive, and the adhesive is in contact with the antenna, the dielectric window allows heat received from the plasma to be efficiently transferred to the antenna via the adhesive (the heat transferred to the antenna flows into the vacuum chamber via the frame, as described above). Suitable adhesives include, but are not limited to, silicone resins, epoxy resins, Teflon (registered trademark) resins, and glass adhesives such as fritted glass.

[0020] When the frame and antenna are mounted on the cover member, it is preferred to further include an insulator plate, which is a plate made of an insulator and contacts the frame. This plate can withstand the pressure difference between the vacuum container and the atmosphere, while also electrically insulating the antenna from the frame. Because heat from the antenna flows to the frame through the insulator plate, the insulator plate is preferably made of a material with high thermal conductivity, such as AlN.

[0021] When the insulator plate is included, it is preferable to further fill the gap between the antenna and the insulator plate with a dielectric adhesive. This allows heat generated by the antenna to be efficiently transferred to the insulator plate via the adhesive, similar to the adhesive filling between the antenna and the dielectric window. Suitable adhesives include, but are not limited to, resins such as silicone, epoxy, and Teflon resins, or glass such as fritted glass.

[0022] In planar antennas, high-frequency currents flow only near the surface due to the skin effect. Therefore, making planar antennas thicker wastes material. Therefore, the thickness of the antenna is preferably thin enough to maintain mechanical strength, for example, 1 to 1000 μm. Furthermore, planar antennas are not limited to flat (uncurved) surfaces; they can also be curved. Furthermore, planar antennas can also be flexible.

[0023] [Effects of the Invention]

[0024] According to the present invention, the structure of the cooling mechanism of the antenna in an inductively coupled plasma source can be simplified, thereby reducing the cost required for the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Part (a) is a schematic diagram of a plasma processing apparatus including a first embodiment of the plasma source of the present invention. Figure 1 Part (b) is a partial enlarged view of the plasma source and its surroundings.

[0026] Figure 2 This is a diagram showing the flow of heat in the plasma source of the first embodiment using arrows.

[0027] Figure 3 This is a diagram showing the flow of current in the antenna in the plasma source of the first embodiment using arrows.

[0028] Figure 4 This is a graph showing the electron density of plasma generated by the plasma source of the first embodiment and a plasma source using an antenna composed of a conventional conductive tube.

[0029] Figure 5 This is a schematic diagram showing the configuration of a second embodiment of the plasma source of the present invention.

[0030] Figure 6 This is a diagram showing the flow of heat in the plasma source of the second embodiment using arrows.

[0031] Figure 7 This is a graph showing the results of measuring temperature changes of the antenna (a), the first insulating material (b), the second insulating material (c), and the dielectric window (d) when the plasma source of the second embodiment generates plasma.

[0032] Description of reference numerals:

[0033] 1: Plasma treatment device

[0034] 10,10A: Plasma source

[0035] 11,11A: Antenna

[0036] 110:Laminated body

[0037] 12: Antenna fixing frame

[0038] 121: frame body

[0039] 122: protrusion

[0040] 123: Bolts for fixing the antenna fixing frame to the wall of the vacuum container

[0041] 13: Insulation material

[0042] 131A: 1st insulating material

[0043] 132A: Second insulating material

[0044] 1321, 1325: A portion of the upper surface of the second insulating material

[0045] 1322, 1324: Side of the second insulating material

[0046] 1323: Bottom surface of the second insulating material

[0047] 134: Adhesive

[0048] 14: Dielectric window (Japanese original: dielectric window)

[0049] 15: High frequency current supply bar

[0050] 151: Feed terminal

[0051] 1511,1512: High-frequency current supply block

[0052] 152: Feeder

[0053] 153: Bolts for fixing the high-frequency current supply block to the second insulating material

[0054] 154: Bolts for fixing the high-frequency current supply block to the first insulating material

[0055] 16: Airtight maintenance unit

[0056] 161: Sealing material

[0057] 21: Vacuum container

[0058] 211: Wall of vacuum container

[0059] 212: The inner space of the vacuum container

[0060] 213: Opening of vacuum container

[0061] 22: Vacuum pump

[0062] 23: Gas supply unit

[0063] 24: Base holding portion

[0064] 25: Substrate loading and unloading

[0065] 251: Cover member of substrate loading and unloading port

[0066] 26: High frequency power supply

[0067] 27: Impedance matching box

[0068] S: Matrix. DETAILED DESCRIPTION

[0069] use Figures 1 to 7 , an embodiment of the plasma source of the present invention is described.

[0070] (1) Configuration of the plasma source of the first embodiment

[0071] Figure 1This figure schematically illustrates a plasma source 10 according to a first embodiment, and a plasma processing apparatus 1 including the plasma source 10. The plasma processing apparatus 1 is a film forming apparatus utilizing a plasma CVD method and includes, in addition to the plasma source 10, a vacuum container 21, a vacuum pump 22, a gas supply unit 23, a substrate holding unit 24, a substrate loading / unloading port 25, a high-frequency power supply 26, and an impedance matching box 27.

[0072] First, the components of the plasma processing apparatus 1 other than the plasma source 10 will be described. The vacuum container 21 has a wall 211 made of metal (e.g., stainless steel), and plasma is generated in an internal space 212 of the vacuum container 21 formed on the inner side of the wall 211. The vacuum pump 22 is a pump for evacuating the internal space 212. The gas supply unit 23 is composed of a cylinder (not shown) and a gas introduction pipe, and supplies plasma generating gas such as argon or hydrogen, and film forming raw material gas to the internal space 212. Furthermore, when the substrate S is processed without using the film forming raw material gas, such as in the case of film formation by sputtering or cleaning of the substrate S using plasma, only the plasma generating gas is supplied to the internal space 212 from the gas supply unit 23. The substrate holding unit 24 holds the substrate S. The substrate loading / unloading port 25 is provided on the wall 211. It is used to allow the substrate S to pass through when loading the substrate S from outside the vacuum chamber 21 into the substrate holding portion 24 before film formation, and when unloading the substrate S from the substrate holding portion 24 to outside the vacuum chamber 21 after film formation. The substrate loading / unloading port 25 is sealed with a cover member 251 except when loading and unloading the substrate S. The high-frequency power supply 26 supplies high-frequency current to the antenna 11 described below. The impedance matching device 27 adjusts the impedance to efficiently direct the high-frequency current from the high-frequency power supply 26 to the antenna 11.

[0073] In this embodiment, two plasma sources 10 are provided in one plasma processing apparatus 1. However, the number of plasma sources 10 is not limited thereto and may be one or three or more. Each plasma source 10 includes an antenna 11, an antenna fixing frame (the aforementioned frame) 12, a plate-shaped insulating material 13, a plate-shaped dielectric window 14, two high-frequency current supply bars 15, and an airtightness retaining portion 16.

[0074] In this embodiment, antenna 11 is a planar antenna made of a metal plate. While copper is used as the material for antenna 11, other conductive materials may be used. Two high-frequency current supply bars 15 are in contact with one surface of antenna 11. These two high-frequency current supply bars 15 are approximately parallel to each other and are connected to a high-frequency power source 26 and an impedance matching device 27 via a feed terminal 151 and a feed line 152. Each high-frequency current supply bar 15 is 30 mm long, and the distance between the two high-frequency current supply bars 15 is 150 mm.

[0075] On the aforementioned one surface of the antenna 11, the insulating material 13 is in contact with it, except for the portion in contact with the high-frequency current supply rod 15. The surface of the insulating material 13 in contact with the antenna 11 is provided with a notch for accommodating the high-frequency current supply rod 15. On the other surface of the antenna 11, the dielectric window 14 is in contact with it. Thus, the antenna 11 is sandwiched between the insulating material 13 and the dielectric window 14. In other words, a laminate 110 is formed in which the insulating material 13, the antenna 11, and the dielectric window 14 are stacked in this order. The laminate 110 is positioned with one side of the dielectric window 14 facing the opening 213 provided in the wall (upper wall) 211 of the vacuum container 21.

[0076] The insulating material 13 can be made of alumina, zirconium oxide, silicon nitride, aluminum nitride, etc. Among these materials, aluminum nitride is suitable due to its relatively high thermal conductivity. The dielectric window 14 can also be made of the same material as the insulating material 13.

[0077] The antenna fixing frame 12 includes a main frame portion 121 that surrounds the side of the laminate 110, and a protrusion 122 that protrudes from the main frame portion 121 toward the surface of the laminate 110 on the insulating material 13 side, covering a portion of the surface. With the insulating material 13 side of the laminate 110 as the upper side, the antenna fixing frame 12 exhibits an inverted L-shape in a cross-section perpendicular to the laminate 110. The main frame portion 121 includes a hole extending from the upper surface to the lower surface. Bolts 123 inserted through the hole secure the antenna fixing frame 12 to the wall (upper wall) 211 of the vacuum container 21, located around the opening 213. An airtight retaining portion 16 is disposed on the upper surface of the wall (upper wall) 211, further inward of the main frame portion 121. The laminate 110 is secured by being sandwiched between the protrusion 122 and the airtight retaining portion 16. The airtightness maintaining portion 16 is provided with sealing materials (O-rings) 161 on the upper and lower surfaces of the frame-shaped member. The upper sealing material 161 is pressed against the dielectric window 14, while the lower sealing material 161 is pressed against the wall (upper wall) 211. With this configuration, the plasma source 10 functions as a cover member that hermetically closes the opening 213.

[0078] In order to increase the high-frequency electromagnetic field generated in the internal space 212 of the vacuum container 21, the dielectric window 14 in the laminate 110 is preferably thinner. In addition, in the antenna 11, the high-frequency current flows only near the surface due to the skin effect, so making the antenna 11 thicker will waste material. On the other hand, the dielectric window 14 side of the laminate 110 is in contact with the vacuum internal space 212 of the vacuum container 21, and the insulating material 13 side is in contact with the atmosphere, and is subjected to the force generated by the pressure difference between the vacuum and atmospheric pressure, so it needs to have mechanical strength that can withstand this pressure difference. Therefore, the insulating material 13 is preferably thicker. However, if the insulating material 13 is too thick, the heat dissipation efficiency of the antenna 11 is reduced. In addition, the required mechanical strength also depends on the size of the opening 213 of the vacuum container 21. Considering the above aspects, the thickness of the antenna 11, the insulating material 13 and the dielectric window 14 is determined. In this embodiment, opening 213 is a rectangle with a long side of 210 mm and a short side of 160 mm. The thickness of antenna 11 is set to 0.6 mm, the thickness of insulating material 13 is set to 20 mm, and the thickness of dielectric window 14 is set to 3 mm. Of course, these thicknesses can be modified as appropriate. For example, the thickness of antenna 11 can be set within the range of 1 to 1000 μm, the thickness of insulating material 13 can be set within the range of 3 to 20 mm, and the thickness of dielectric window 14 can be set within the range of 5 mm or less. Furthermore, the thicknesses of each component may also be outside the ranges listed here.

[0079] Furthermore, in the plasma source 10 of this embodiment, a cooling mechanism for cooling the antenna 11 by flowing a coolant is not provided.

[0080] (2) Operation of the plasma source in the first embodiment

[0081] The operation of the plasma source 10 according to the first embodiment will be described together with the operation of the plasma processing apparatus 1 including the plasma source 10 .

[0082] First, the cover member 251 of the substrate loading / unloading port 25 is opened, and the substrate S is loaded into the internal space 212 of the vacuum container 21. Thereafter, the substrate S is placed on the substrate holding portion 24 and held by the substrate holding portion 24. Thereafter, the cover member 251 of the substrate loading / unloading port 25 is closed, and the internal space 212 of the vacuum container 21 is evacuated by the vacuum pump 22. Furthermore, the plasma generating gas and the film forming raw material gas are supplied to the internal space 212 by the gas supply portion 23. Subsequently, a high-frequency current is introduced from the high-frequency power supply 26 to the antenna 11. As a result, a high-frequency electromagnetic field is generated in the internal space 212, and plasma is generated by dissociating the molecules of the plasma generating gas. Through this plasma, the molecules of the film forming raw material gas are decomposed and deposited on the substrate S, thereby forming a film.

[0083] During the film formation, heat is generated from the antenna 11 due to the flow of high frequency current. Figure 2 As shown by the arrow in FIG, the heat flows through the insulating material 13 and the antenna mounting frame 12 into the wall 211 of the vacuum chamber 21. Here, the antenna 11 is surrounded by the antenna mounting frame 12, so the heat generated by the antenna 11 can be efficiently discharged from the surrounding area to the antenna mounting frame 12. Furthermore, the wall 211 of the vacuum chamber 21 has a sufficiently large heat capacity and also dissipates heat through contact with the atmosphere, thus effectively dissipating heat and cooling the antenna 11. This cooling process eliminates the need for a cooling mechanism that uses a flowing refrigerant to cool the antenna 11. Therefore, the plasma source 10 of this embodiment can reduce both initial and operating costs.

[0084] Furthermore, in this embodiment, a planar antenna 11 is used, and a high-frequency current is supplied between two high-frequency current supply bars 15 that are in contact with the surface of the antenna 11 and are substantially parallel to each other. Therefore, the high-frequency current is as follows: Figure 3 As shown by the arrows in the figure, the current diffuses along the surface of the planar antenna. Therefore, a larger current can flow through antenna 11 of this embodiment than through a linear antenna. Furthermore, heat is dissipated from the surface of planar antenna 11 to the atmosphere via insulating material 13, thus achieving higher heat dissipation efficiency.

[0085] The following are the results of an experiment conducted to measure the electron density of plasma generated using the plasma source of the first embodiment. As a comparative example, the results of measuring the electron density of plasma generated while allowing a coolant to flow through the tube of a tubular antenna made of a conventional conductive tube are also shown. The tubular antenna was bent 90° at two locations, forming a roughly U-shaped shape, with the two locations separated by 100 mm. In this experiment, one plasma source and one tubular antenna of the first embodiment were used, and argon gas was introduced as the plasma-generating gas at a pressure of 1.0 Pa and a flow rate of 10 sccm. Subsequently, high-frequency power was input to the antenna in the range of 50 to 400 W, and the electron density of the plasma was measured using a Langmuir probe at a distance of 115 mm from the antenna.

[0086] The experimental results are shown in Figure 4 . In both the first embodiment and the comparative example, the electron density increases in proportion to the magnitude of the high-frequency power. This means that in both the first embodiment and the comparative example, the antenna can be cooled smoothly even if the high-frequency power is increased. Therefore, it can be said that according to the structure of the first embodiment, without providing a cooling mechanism using a refrigerant, the antenna can be cooled in the same manner as in the comparative example provided with such a cooling mechanism, and a lower-cost plasma source can be obtained. In addition, with regard to the electron density, the first embodiment is higher than the comparative example. It is believed that the reason for this is that the inductance of the antenna of the first embodiment is smaller than that of the comparative example, and therefore the high-frequency current becomes larger.

[0087] (3) Configuration of the plasma source of the second embodiment

[0088] At Figure 5 The schematic structure of the plasma source 10A of the second embodiment is shown. The plasma source 10A is similar to the plasma source 10 of the first embodiment and is mounted on the wall 211 of the vacuum container 21 so as to close the opening 213 of the vacuum container 21 provided in the plasma processing apparatus 1. Figure 5 In FIG. 1 , among the components of the plasma processing apparatus other than the plasma source 10A, only a portion of the wall 211 and the opening 213 of the vacuum container 21 are shown, and the rest of the components are omitted from illustration.

[0089] The plasma source 10A includes an antenna 11A, an antenna fixing frame 12, a first insulating material 131A, a second insulating material 132A, a dielectric window 14, two high-frequency current supply blocks 1511 and 1512, and an airtight holding portion 16. The configuration of the antenna fixing frame 12, the dielectric window 14, and the airtight holding portion 16 is the same as that of the first embodiment.

[0090] The first insulating material 131A is placed on the dielectric window 14 and has a frame shape with the center of the insulating plate hollowed out. The antenna 11A and the second insulating material 132A are arranged in the frame.

[0091] The antenna 11A is a planar antenna formed of a flexible metal sheet having a thickness of 500 μm. As such a sheet, a metal foil formed of copper, aluminum, or the like is preferably used.

[0092] Second insulating material 132A is composed of a roughly rectangular parallelepiped insulator. Antenna 11A is in contact with its bottom surface 1323, two of its four side surfaces 1322 and 1324 that face each other, and portions of its top surface 1321 and 1325 that contact these two side surfaces 1322 and 1324, respectively. In other words, antenna 11A is arranged such that it begins with portion 1321 of its top surface that contacts one side surface 1322 and winds around that side surface 1322, bottom surface 1323, the other side surface 1324, and portion 1325 of its top surface that contacts the other side surface 1324. In this state, with bottom surface 1323 of second insulating material 132A facing downward, antenna 11A and second insulating material 132A are arranged within the frame of first insulating material 131A in this manner. Therefore, the portion of the antenna 11A wound around the bottom surface 1323 of the second insulating material 132A faces the dielectric window 14 , and the portion wound around the side surfaces 1322 and 1324 of the second insulating material 132A faces the first insulating material 131A and the antenna fixing frame 12 outside of the first insulating material 131A.

[0093] Gaps are provided between first insulating material 131A and antenna 11A, and between antenna 11A and dielectric window 14 below it. These gaps are filled with adhesive 134, a dielectric resin, typically silicone grease. This adhesive 134 improves thermal contact between first insulating material 131A and antenna 11A, and between antenna 11A and dielectric window 14, compared to direct contact.

[0094] Two high-frequency current supply blocks 1511 and 1512 are fixed to the first insulating material 131A by bolts 154. Therefore, the first insulating material 131A and the second insulating material 132A are connected via the high-frequency current supply blocks 1511 and 1512.

[0095] The first insulating material 131A is laterally surrounded by the main frame portion 121 of the antenna fixing frame 12, and a portion of its upper surface contacts the protrusion 122 of the antenna fixing frame 12. The first insulating material 131A, dielectric window 14, and airtight member 16, when stacked, are sandwiched above and below by the protrusion 122 and the upper surface of the wall 211 of the vacuum chamber 21. The main frame portion 121 is secured to the wall 211 with bolts 123, thereby securing the three components. Sealants (O-rings) 161 are provided between the dielectric window 14 and the airtight member 16, and between the airtight member 16 and the upper surface of the wall 211 of the vacuum chamber 21.

[0096] The two high-frequency current supply blocks 1511 and 1512 are both metal blocks, one of which is connected to one electrode of the high-frequency power supply 26, and the other is connected to the other electrode of the high-frequency power supply 26 (at Figure 5 (The high-frequency power supply 26 is omitted from the illustration.) A high-frequency current supply block 1511 is located in the aforementioned region 1321 on the upper surface of the second insulating material 132A, pressing the antenna 11A against the second insulating material 132A, thereby securing the antenna. Another high-frequency current supply block 1512 is located in the aforementioned region 1325, pressing the antenna 11A against the second insulating material 132A, thereby securing the antenna. High-frequency current supply blocks 1511 and 1512, excluding the region where the antenna 11A is located, contact the upper surface of the second insulating material 132A and are secured to the second insulating material 132A via bolts 153.

[0097] (4) Operation of the plasma source in the second embodiment

[0098] The plasma processing apparatus equipped with the plasma source 10A of the second embodiment utilizes the same method as the plasma processing apparatus 1 of the first embodiment. A substrate S is held in the substrate holder 24. After the interior space 212 of the vacuum vessel 21 is evacuated, a plasma-generating gas and a film-forming source gas are supplied from the gas supply unit 23 into the interior space 212 of the vacuum vessel 21. A high-frequency current is then introduced from the high-frequency power supply 26 to the antenna 11A. This generates a high-frequency electromagnetic field within the interior space 212 of the vacuum vessel 21. This high-frequency electromagnetic field dissociates the molecules of the plasma-generating gas, thereby generating plasma. The molecules of the film-forming source gas formed by the decomposition of the plasma then deposit on the substrate S, thereby forming a film. The generation of the high-frequency electromagnetic field within the interior space 212 of the vacuum vessel 21 is primarily contributed by the portion of the antenna 11A that faces the interior space 212 and is wrapped around the bottom surface 1323 of the second insulating material 132A. Therefore, this portion can be considered a planar antenna.

[0099] During the film formation process, the heat generated from the antenna 11A due to the flow of high frequency current is as follows: Figure 6 As shown by the arrows in the figure, a portion of the heat flows through the second insulating material 132A and the high-frequency current supply blocks 1511 and 1512 into the first insulating material 131A. Another portion flows through the high-frequency current supply blocks 1511 and 1512 (without passing through the second insulating material 132A) into the first insulating material 131A. Yet another portion flows through the adhesive 134 into the first insulating material 131A. The heat that flows into the first insulating material 131A through various pathways in this manner flows through the antenna mounting frame 12 and into the wall 211 of the vacuum vessel 21. As described above, the wall 211 of the vacuum vessel 21 has a sufficiently large heat capacity and also dissipates heat through contact with the atmosphere. Therefore, heat can be effectively dissipated from the antenna 11A, cooling the antenna 11A. Here, since the antenna 11A is surrounded by the antenna mounting frame 12, the heat generated by the antenna 11A can be efficiently dissipated to the antenna mounting frame 12. Furthermore, in this embodiment, the portion of antenna 11A wrapped around side surfaces 1322 and 1324 of second insulating material 132A faces antenna mounting frame 12, thereby further improving the efficiency of dissipating heat from antenna 11A to antenna mounting frame 12. Furthermore, heat from antenna 11A can also be dissipated into the atmosphere through second insulating material 132A.

[0100] The plasma source 10A of the second embodiment does not require a cooling mechanism for cooling the antenna 11A by flowing a coolant, as in the first embodiment. Therefore, the initial cost and running cost of the device can be suppressed.

[0101] To verify the cooling efficiency of the antenna and other components in the plasma source of the second embodiment, the following experimental results are described. Temperature sensors were attached to each of the antenna 11A, first insulating material 131A, second insulating material 132A, and dielectric window 14, and temperature changes at each component during plasma generation were measured. Experiments were also conducted in which the gaps between antenna 11A and first insulating material 131A and between antenna 11A and dielectric window 14 were not filled with adhesive 134 (maintaining the gaps). The gaps were set to 2 mm, silicone grease was used as adhesive 134, the pressure of argon, the plasma-generating gas, was set to 1.0 Pa, the flow rate of argon was set to 10 sccm, and the high-frequency power input to antenna 11A was set to 500 W. The temperatures at each component were measured immediately after the plasma was ignited (0 minutes), and then 5, 10, 15, and 30 minutes later.

[0102] The results are shown in Figure 7 Comparing the gaps filled with adhesive 134 with those not filled, it was found that while no significant temperature difference was observed between the first insulating material 131A and the second insulating material 132A, the antenna 11A and the dielectric window 14 exhibited a significant temperature suppression effect when filled with adhesive 134.

[0103] The plasma source of the present invention is not limited to the above-described embodiment, and can be modified within the scope of the gist of the present invention.

Claims

1. A plasma source, which is a device for generating plasma in a vacuum container, comprising: a) a frame provided on a wall of the vacuum container; b) a planar antenna fixed within the frame; and c) an insulator plate, the insulator plate being a plate made of an insulator, disposed on the outside of the vacuum container of the antenna and in contact with the frame; Furthermore, no cooling mechanism for cooling the antenna by flowing a refrigerant is provided; The frame and the antenna are provided on a cover member that closes an opening of the vacuum container; A dielectric adhesive is filled between the antenna and the insulator plate; The antenna is cooled by transferring heat generated by the antenna to the vacuum container, which is a heat bath, via the frame to which the antenna is fixed.

2. The plasma source as claimed in claim 1, wherein the frame is made of metal.

3. The plasma source according to claim 1, further comprising a dielectric window, wherein the dielectric window is a plate material and is arranged inside the vacuum container of the antenna. 4 . The plasma source according to claim 3 , further comprising a vacuum seal disposed between the wall surrounding the opening and the dielectric window. 5 . The plasma source according to claim 3 , wherein a dielectric adhesive is filled between the antenna and the dielectric window.

6. The plasma source as claimed in claim 3, wherein the thickness of the dielectric window is less than 5 mm.

7. The plasma source according to claim 1 or 2, wherein the thickness of the antenna is 1 to 1000 μm.

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