Fastening structure, fastening method, and plasma processing device

Abstract

The present invention provides a fastening structure and fastening method, as well as a plasma processing apparatus, for fastening a metal component and a covering component disposed within a plasma-generating processing vessel via a fastening screw, capable of suppressing the adhesion of deposits to the head of the fastening screw. The fastening structure includes: a plurality of metal components disposed within the processing vessel, each having an exposed surface exposed to the plasma generated within the processing vessel and a threaded hole; a covering component disposed across the exposed surfaces of the plurality of metal components, having insulating properties and a through-hole; a metal fastening screw having a screw head that penetrates the through-hole and is screwed into the threaded hole to fasten the covering component to the metal component; and a screw cover covering the screw head, the screw cover including: a first metal base that contacts the screw head; and a first protective film composed of a ceramic spray film that covers at least a portion of the surface of the first base.

Description

Technical Field

[0001] The present invention relates to a fastening structure and a fastening method, and a plasma processing device. Background Art

[0002] Patent document 1 discloses a plasma processing apparatus for performing plasma processing on a substrate to be processed in a processing space. The plasma processing apparatus has a metal window formed by a plurality of conductive partial windows, and the metal window closes the opening on the upper surface side of the processing container to form a processing space. A resin insulating component is provided between adjacent partial windows. A ceramic insulating component cover covers the surface of the insulating component on the processing space side, and a plasma antenna for plasma-forming a processing gas by inductive coupling is provided on the upper side of the metal window. According to the plasma processing apparatus disclosed in Patent document 1, by using a ceramic insulating component cover to protect the resin insulating component from the influence of plasma, it is possible not only to plasma-form the processing gas supplied to the processing space, but also to maintain the necessary function of the metal window and to make the metal window lightweight.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-27775. Summary of the Invention

[0006] Problems to be solved by the invention

[0007] The present invention provides a fastening structure and a fastening method as well as a plasma processing apparatus capable of fastening a metal component and a covering component arranged inside a processing container and being advantageous in suppressing the attachment of deposits to the head of a fastening screw.

[0008] Technical means to solve the problem

[0009] A fastening structure according to one embodiment of the present invention includes: a plurality of metal parts arranged inside a processing container, having exposed surfaces and threaded holes exposed to the plasma generated inside the processing container; a covering part arranged so as to span the exposed surfaces of the plurality of metal parts, having insulating properties, and having a through hole; a metal fastening screw having a screw head, which fastens the covering part to the metal part by passing through the through hole and being screwed into the threaded hole; and a screw covering covering the screw head, the screw covering including: a first metal base in contact with the screw head; and a first protective film composed of a ceramic sprayed film covering at least a portion of the surface of the first base.

[0010] Effects of the Invention

[0011] According to the present invention, a metal member disposed inside a processing container and a covering member can be fastened together, and adhesion of deposits to the head of a fastening screw can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a longitudinal sectional view showing an example of a plasma processing apparatus according to an embodiment.

[0013] Figure 2 This is a top view of an example of a metal window as viewed from the processing chamber side.

[0014] Figure 3 yes Figure 2 The enlarged view of part III is a diagram showing the intersection area of ​​multiple covering members.

[0015] Figure 4 yes Figure 3 The IV-IV arrow view is a longitudinal sectional view of an example of the fastening structure of the first embodiment.

[0016] Figure 5 It is a longitudinal sectional view of an example of the fastening structure of the second embodiment.

[0017] Figure 6 It is a longitudinal sectional view of an example of the fastening structure of the third embodiment.

[0018] Figure 7 It is a longitudinal sectional view of an example of the fastening structure according to the fourth embodiment.

[0019] Figure 8 It is a longitudinal sectional view of an example of the fastening structure according to the fifth embodiment.

[0020] Description of Reference Signs

[0021] 20: Processing Containers

[0022] 31: Metal window unit (metal parts)

[0023] 34a: Reveal

[0024] 38: Covering member (first covering member)

[0025] 38a: Through hole

[0026] 39, 39A: Covering member (second covering member)

[0027] 39a: Through hole

[0028] 40, 40A: Fastening structure

[0029] 41: Fastening screw

[0030] 42: Screw head

[0031] 44: Screw cover

[0032] 45: First base

[0033] 46: First protective film DETAILED DESCRIPTION

[0034] Hereinafter, a fastening structure and a fastening method and a plasma processing apparatus according to embodiments of the present invention will be described with reference to the accompanying drawings. In this specification and the accompanying drawings, substantially identical components are denoted by identical reference numerals, and duplicate descriptions are omitted.

[0035] [Plasma Processing Apparatus According to Embodiment]

[0036] First, refer to Figure 1 and Figure 2 , an example of a plasma processing apparatus according to an embodiment of the present invention is described. Here, Figure 1 is a longitudinal sectional view showing an example of a plasma processing apparatus according to an embodiment, Figure 2 This is a top view of an example of a metal window as viewed from the processing chamber side.

[0037] Figure 1 The plasma processing device 100 shown is an inductively coupled plasma (ICP) processing device that performs various substrate processing methods on a substrate G (hereinafter referred to as a "substrate") that is rectangular when viewed from above and is used for a flat panel display (hereinafter referred to as "FPD"). As the material of the substrate, glass is mainly used, and transparent synthetic resins and the like can sometimes be used depending on the application. Here, the substrate processing includes etching processing or film forming processing using the CVD (Chemical Vapor Deposition) method. Examples of FPDs include liquid crystal displays (LCDs), electroluminescent displays (ELs), plasma display panels (PDPs), etc. The substrate includes not only the form in which a circuit pattern is formed on its surface, but also a supporting substrate. Furthermore, the planar dimensions of FPD substrates have increased with each generation. The planar dimensions of substrates G processed by the plasma processing apparatus 100 range from approximately 1500 mm × 1800 mm for the 6th generation to approximately 3000 mm × 3400 mm for the 10.5th generation, for example. Furthermore, the thickness of substrates G ranges from 0.2 mm to several millimeters.

[0038] Figure 1 The illustrated plasma processing apparatus 100 includes a rectangular parallelepiped box-shaped processing container 20, a substrate mounting table 70 disposed within the processing container 20 and having a rectangular outer shape when viewed from above and capable of mounting a substrate G, and a control unit 90. Alternatively, the processing container may have a cylindrical box-shaped or elliptical box-shaped shape, in which case the substrate mounting table may also have a circular or elliptical shape, and the substrate mounted on the substrate mounting table may also have a circular shape.

[0039] The processing container 20 is divided into two spaces, upper and lower, by a metal window 30. The upper space, antenna chamber A, is formed by the upper chamber 13, while the lower space, processing chamber S, is formed by the lower chamber 17. Within the processing container 20, a rectangular ring-shaped support frame 14 is disposed at the boundary between the upper chamber 13 and the lower chamber 17, projecting toward the interior of the processing container 20. The metal window 30 is mounted on the support frame 14.

[0040] The upper chamber 13 forming the antenna chamber A is formed of the side walls 11 and the top plate 12 and is formed entirely of metal such as aluminum or an aluminum alloy.

[0041] The lower chamber 17 having the processing chamber S therein is formed by a side wall 15 and a bottom plate 16 , and is formed entirely of a metal such as aluminum or an aluminum alloy.

[0042] Furthermore, the support frame 14 is formed of conductive metal such as aluminum or aluminum alloy, and can also be called a metal frame.

[0043] A rectangular annular (closed loop) sealing groove 22 is formed at the upper end of the side wall 15 of the lower chamber 17, and a sealing component 23 such as an O-ring is embedded in the sealing groove 22. The abutting surface of the support frame 14 holds the sealing component 23, thereby forming a sealing structure of the lower chamber 17 and the support frame 14.

[0044] A feed-in / feed-out port 18 is formed on the side wall 15 of the lower chamber 17 for feeding substrates G into and out of the lower chamber 17. The feed-in / feed-out port 18 is configured to be freely openable and closable by a gate valve 24. The lower chamber 17 is adjacent to a transport chamber (not shown) having a built-in transport mechanism. The gate valve 24 is controlled to open and close, and the transport mechanism is used to feed substrates G into and out of the lower chamber 17 through the feed-in / feed-out port 18.

[0045] Furthermore, multiple exhaust ports 19 are formed in the bottom plate 16 of the lower chamber 17. A gas exhaust pipe 25 is connected to each exhaust port 19. The gas exhaust pipe 25 is connected to an exhaust device 27 via an on-off valve 26. The gas exhaust pipe 25, the on-off valve 26, and the exhaust device 27 form a gas exhaust section 28. The exhaust device 27 includes a vacuum pump such as a turbomolecular pump and is configured to evacuate the interior of the lower chamber 17 to a predetermined vacuum level during processing. Furthermore, a pressure gauge (not shown) is provided at an appropriate location in the lower chamber 17, and monitoring information obtained from the pressure gauge is transmitted to the control unit 90.

[0046] The substrate mounting table 70 includes a base material 71 and an electrostatic chuck 76 formed on an upper surface 71 a of the base material 71 .

[0047] The substrate 71 has a rectangular shape when viewed from above and has a planar dimension approximately the same as that of the substrate G placed on the substrate mounting table 70. The length of the long side of the substrate 71 can be set to approximately 1800 mm to 3400 mm, and the length of the short side can be set to approximately 1500 mm to 3000 mm. In relation to these planar dimensions, the thickness of the substrate 71 can be set to approximately 50 mm to 100 mm, for example.

[0048] A curved temperature control medium flow path 72a is provided on substrate 71 so as to cover the entire rectangular plane. The flow path 72a is made of stainless steel, aluminum, or an aluminum alloy. Alternatively, temperature control medium flow path 72a may be provided on electrostatic chuck 76. Furthermore, substrate 71 may be formed of a laminate of two components made of aluminum or an aluminum alloy, rather than a single component as shown in the figure.

[0049] A box-shaped base 78 made of an insulating material and having a stepped portion inside is fixed to the bottom plate 16 of the lower chamber 17 , and the substrate mounting table 70 is mounted on the stepped portion of the base 78 .

[0050] An electrostatic chuck 76 capable of directly placing a substrate G is formed on the upper surface 71a of the base material 71. The electrostatic chuck 76 includes a ceramic layer 74 as a dielectric coating formed by spraying a ceramic such as alumina, and a conductive layer 75 (electrode) embedded in the ceramic layer 74 and having an electrostatic adsorption function.

[0051] Conductive layer 75 is connected to DC power supply 85 via power supply line 84. When a switch (not shown) inserted into power supply line 84 is turned on by control unit 90, a DC voltage is applied from DC power supply 85 to conductive layer 75, thereby generating Coulomb force. This Coulomb force electrostatically attracts substrate G to the upper surface of electrostatic chuck 76, maintaining the substrate G placed on upper surface 71a of substrate 71.

[0052] A curved temperature control medium flow path 72a is provided on the base material 71 constituting the substrate mounting table 70 so as to cover the entire rectangular plane. Connected at both ends of the temperature control medium flow path 72a are a delivery pipe 72b for supplying the temperature control medium to the temperature control medium flow path 72a and a return pipe 72c for discharging the temperature control medium, which has been heated after flowing through the temperature control medium flow path 72a.

[0053] like Figure 1 As shown, the delivery pipe 72b and the return pipe 72c are connected to the delivery flow path 87 and the return flow path 88 respectively, and the delivery flow path 87 and the return flow path 88 are connected to the cooler 86. The cooler 86 has: a main body that controls the temperature and discharge flow of the temperature control medium; and a pump that pressurizes the temperature control medium (both are not shown). In addition, a refrigerant can be used as the temperature control medium, and the refrigerant can use GALDEN (registered trademark) or FLUORINERT (registered trademark) and the like. The temperature control method shown in the example is a method of circulating the temperature control medium in the substrate 71, but it can also be a method of using a heater built into the substrate 71 to perform temperature control, or it can be a method of using both the temperature control medium and the heater to perform temperature control. In addition, instead of the heater, temperature control accompanied by heating can be performed by circulating a high-temperature temperature control medium. In addition, the heater as a resistor is formed of tungsten or molybdenum, or a compound of any of these metals and aluminum oxide or titanium. In the example shown in the figure, the temperature control medium flow path 72 a is formed in the base material 71 , but, for example, the electrostatic chuck 76 may also have a temperature control medium flow path.

[0054] A temperature sensor (not shown) such as a thermocouple is provided on the substrate 71. Monitoring information generated by the temperature sensor is constantly transmitted to the control unit 90. Based on this transmitted monitoring information, the control unit 90 controls the temperature of the substrate 71 and substrate G. More specifically, the control unit 90 adjusts the temperature and flow rate of the temperature control medium supplied from the cooler 86 to the delivery flow path 87. The temperature control medium, which has undergone temperature and flow adjustments, is then circulated through the temperature control medium flow path 72a, thereby controlling the temperature of the substrate mounting table 70. Alternatively, a temperature sensor such as a thermocouple may be provided on the electrostatic chuck 76, for example.

[0055] A stepped portion is formed by the outer periphery of electrostatic chuck 76, substrate 71, and the upper surface of base 78. A rectangular frame-shaped focus ring 79 is placed on this stepped portion. When focus ring 79 is placed on the stepped portion, the upper surface of focus ring 79 is set lower than the upper surface of electrostatic chuck 76. Focus ring 79 is formed of ceramic such as alumina or quartz.

[0056] A power supply component 80 is connected to the lower surface of the substrate 71. A power supply line 81 is connected to the lower end of the power supply component 80, and the power supply line 81 is connected to a high-frequency power supply 83 serving as a bias power supply via a matching device 82 for impedance matching. By applying high-frequency electric power of, for example, 3.2 MHz from the high-frequency power supply 83 to the substrate mounting table 70, an RF bias is generated, and ions generated by the high-frequency power supply 56 serving as a plasma generation source, which will be described below, can be adsorbed onto the substrate G. Therefore, in the plasma etching process, both the etching rate and the etching selectivity can be improved. In this way, the substrate mounting table 70 mounts the substrate G and forms a bias electrode for generating the RF bias. At this time, the portion inside the chamber that is at ground potential functions as a counter electrode to the bias electrode, forming a return loop for the high-frequency electric power. In addition, the metal window 30 can also be configured as part of the return loop for the high-frequency electric power.

[0057] The metal window 30 is formed of a plurality of metal window units 31. The number of metal window units 31 forming the metal window 30 (in Figure 2 9 are shown in the figure) and can be set to various numbers such as 12 and 24.

[0058] The metal window unit 31 includes a conductor plate 32 and a shower plate 34. Both the conductor plate 32 and the shower plate 34 are formed from a non-magnetic, conductive, and corrosion-resistant metal, or a metal that has undergone a corrosion-resistant surface treatment, such as aluminum, an aluminum alloy, or stainless steel. Examples of corrosion-resistant surface treatments include anodizing or ceramic spraying. Furthermore, the exposed surface 34a of the shower plate 34 facing the processing chamber S may be coated with a plasma-resistant coating using anodizing or ceramic spraying. The conductor plate 32 is grounded via a grounding wire (not shown), and the shower plate 34 is also grounded via the conductor plate 32, which is bonded to the shower plate 34.

[0059] Each metal window unit 31 constituting the metal window 30 is suspended from the ceiling 12 of the upper chamber 13 by a plurality of suspenders (not shown). A spacer (not shown) formed of an insulating component is provided above each metal window unit 31, and a high-frequency antenna 51 (an example of an inductive coupling antenna) is provided at a distance from the conductor plate 32 via the spacer. The high-frequency antenna 51 contributes to the generation of plasma and is formed by winding an antenna wire formed of a metal with good conductivity such as copper into a ring or spiral shape. For example, the wire of the ring-shaped antenna can be arranged in multiple layers. Since the high-frequency antenna 51 is provided on the upper surface of the metal window unit 31, it is suspended from the ceiling 12 via the metal window unit 31.

[0060] A gas diffusion groove 33 is formed on the lower surface of the conductor plate 32, along with a through-hole 32b connecting the gas diffusion groove 33 with the upper end surface 32a. A gas inlet pipe 52 is embedded in the through-hole 32b. The shower plate 34 is provided with a plurality of gas ejection holes 35 that connect the gas diffusion groove 33 of the conductor plate 32 and the processing chamber S. The shower plate 34 faces the lower surface of the conductor plate 32 outside the gas diffusion groove 33 and is secured thereto with metal screws (not shown). Alternatively, a gas diffusion groove may be provided on the upper surface of the shower plate.

[0061] Each metal window unit 31 is electrically insulated from the support frame 14 and adjacent metal window units 31 by an insulating member 37. Here, the insulating member 37 is formed of a fluororesin such as PTFE (Polytetrafluoroethylene).

[0062] The end surface 37a of the insulating member 37 facing the processing chamber S is flush with the exposed surface 34a of the shower plate 34 facing the processing chamber S. An insulating cover member 38 (an example of a first cover member) covers the end surface 37a of the insulating member 37 and is disposed so as to straddle the exposed surface 34a of the adjacent shower plate 34. The cover member 38 is formed of a ceramic such as alumina.

[0063] The insulating member 37 is made of a resin such as PTFE, which has high insulating properties and is lightweight. However, the resin is not as plasma-resistant as ceramics such as alumina. Furthermore, it is difficult to form a plasma-resistant coating on the resin surface by anodizing or ceramic spraying.

[0064] Therefore, in the plasma processing apparatus 100, the end surface 37a of the insulating member 37 on the processing chamber S side is covered with a covering member 38 made of, for example, ceramic, so that the insulating member 37 can be protected from the plasma. The insulating members 37 that insulate the support frame 14 from the metal window unit 31 and the adjacent metal window units 31 from each other are covered by the covering member 38. Figure 2 In the process, the processing chamber S side cannot be seen.

[0065] like Figure 2 As shown, each covering member 38 completely covers the insulating member 37 and intersects with each other in the intersection region J. In addition, in the intersection region J, the covering member 39 (an example of the second covering member) covers the plurality of first covering members 38 and is fixed with a metal fastening screw ( Figure 2 The screw cover 44 covers the screw head of the fastening screw to form a fastening structure 40. The fastening structure 40 will be described in detail below.

[0066] return Figure 1A power supply component 53 extending upward from the upper chamber 13 is connected to the high-frequency antenna 51, and a power supply line 54 is connected to the upper end of the power supply component 53. The power supply line 54 is connected to a high-frequency power supply 56 via a matching device 55 for impedance matching.

[0067] By applying high-frequency electric power of, for example, 13.56 MHz to the high-frequency antenna 51 from the high-frequency power supply 56, an induced electric field is formed in the lower chamber 17. This induced electric field converts the processing gas supplied from the shower plate 34 to the processing chamber S into plasma, generating an inductively coupled plasma, and ions in the plasma are supplied to the substrate G.

[0068] High-frequency power supply 56 serves as a plasma generating source, while high-frequency power supply 83 connected to stage 70 serves as a bias source that attracts the generated ions and imparts kinetic energy. By utilizing inductive coupling to generate plasma in the ion source and connecting the bias source, a separate power source, to stage 70 to control ion energy, plasma generation and ion energy control can be performed independently, thereby increasing the degree of processing flexibility.

[0069] like Figure 1 As shown, the gas introduction pipes 52 of the metal window units 31 are integrated into a single location within the antenna chamber A. The gas introduction pipes 52 extend upward and airtightly penetrate the supply port 12a formed in the ceiling 12 of the upper chamber 13. Furthermore, the gas introduction pipes 52 are connected to a processing gas supply source 64 via an airtightly coupled gas supply pipe 61.

[0070] An on-off valve 62 and a flow controller 63, such as a mass flow controller, are inserted midway along the gas supply pipe 61. The gas supply pipe 61, on-off valve 62, flow controller 63, and a process gas supply source 64 form a process gas supply unit 60. Furthermore, the gas supply pipe 61 branches midway, and each branch pipe is connected to an on-off valve, a flow controller, and a process gas supply source (not shown) corresponding to the type of process gas.

[0071] During plasma processing, the processing gas supplied from the processing gas supply unit 60 is supplied to the gas diffusion grooves 33 of the conductive plate 32 included in each metal window unit 31 via the gas supply pipe 61 and the gas introduction pipe 52. The gas is then ejected from the gas diffusion grooves 33 into the processing chamber S via the gas ejection holes 35 of the shower plate 34.

[0072] Furthermore, the gas inlet pipes 52 of each metal window unit 31 may not be combined into one, but may be individually connected to the process gas supply unit 60, so that the supply of process gas is controlled for each metal window unit 31. Alternatively, the gas inlet pipes 52 of the multiple metal window units 31 located outside the metal window 30 may be combined into one, while the gas inlet pipes 52 of the multiple metal window units 31 located inside the metal window 30 may be combined into another one, with each gas inlet pipe 52 independently connected to the process gas supply unit 60 to control the supply of process gas. In other words, the former method implements process gas supply control for each metal window unit 31, while the latter method implements process gas supply control for the outer and inner regions of the metal window 30.

[0073] Furthermore, each metal window unit 31 has its own high-frequency antenna, and control of applying high-frequency electric power to each high-frequency antenna can be performed independently.

[0074] The control unit 90 controls the operation of various components of the plasma processing apparatus 100, such as the cooler 86, high-frequency power supplies 56 and 83, the process gas supply unit 60, and the exhaust unit 28 based on monitoring information transmitted from the pressure gauge. The control unit 90 includes a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory). The CPU performs predetermined processing according to a recipe (processing recipe) stored in the RAM and ROM storage areas. The recipe contains control information for the plasma processing apparatus 100 regarding the processing conditions. This control information includes, for example, the gas flow rate and the pressure within the processing vessel 20, the temperature within the processing vessel 20 and the temperature of the substrate 71, and the processing time.

[0075] The recipes and programs used by the control unit 90 are stored, for example, on a hard disk, an optical disk, a magneto-optical disk, or the like. Alternatively, the recipes and the like may be stored in a removable computer-readable storage medium such as a CD-ROM, DVD, or memory card and stored in the control unit 90 in a readable form. The control unit 90 may also include other user interfaces such as input devices such as a keyboard and mouse for inputting commands, a display device such as a monitor for visually displaying the operating status of the plasma processing apparatus 100, and an output device such as a printer.

[0076] [Fastening Structure and Fastening Method of First Embodiment]

[0077] Next, refer to Figures 2 to 4 , an example of the fastening structure and fastening method of the first embodiment is described. Here, Figure 3 It will Figure 2 The enlarged view of Part III is a view showing the intersection area of ​​multiple covering members. Figure 4 yes Figure 3 The IV-IV arrow view is a longitudinal sectional view of an example of the fastening structure of the first embodiment.

[0078] like Figure 2 As shown, in each intersection region J where the plurality of first covering members 38 intersect, the second covering member 39 covers the plurality of first covering members 38 and is fastened to the metal window unit 31 in a stacked state with the second covering member 39 and the first covering member 38, thereby forming a fastening structure 40. Figure 3 As shown, two insulating members 37 intersecting in a T-shape in plan view are covered by three first covering members 38 , and the ends of the first covering members 38 are arranged in the intersection region J with a slight gap H therebetween.

[0079] exist Figure 3 In the embodiment, the ends of the central first covering member 38A extending in the longitudinal direction are cut away on the left and right sides, and the ends of the left and right first covering members 38B and 38C are loosely fitted with a gap H in the cut away areas.

[0080] The width of the first cover member 38 in the short-side direction is set to a size that allows it to cover the insulating member 37 and to be arranged so as to span the peripheral edge of the metal window unit 31 located to the side of the insulating member 37. Therefore, even if plasma enters from the side of the first cover member 38, it is possible to prevent the plasma from reaching the insulating member 37.

[0081] In the intersection region J, a second covering member 39 is disposed to cover the ends of each first covering member 38. As described in detail below, the second covering member 39 is a ceramic covering member or a covering member having a ceramic sprayed film formed on the surface of a metal base. In this manner, in the intersection region J, the second covering member 39 completely covers the ends of each first covering member 38 and the gap H between them, thereby suppressing the entry of plasma into the gap H.

[0082] like Figure 4 As shown, the exposed surface 34a of the shower plate 34 forming the metal window unit 31 facing the processing chamber S and the end surface 37a of the insulating component 37 are covered by a first ceramic covering component 38, and a second ceramic covering component 39 is similarly stacked on the surface of the first covering component 38.

[0083] The first cover member 38 and the second cover member 39 have through holes 38a and 39a, respectively. The shower plate 34 also has a through hole 34b, and the conductor plate 32 has a threaded hole 32c. The through hole 34b communicates with the threaded hole 32c.

[0084] The first cover member 38 and the second cover member 39 stacked on each other cover the exposed surface 34a of the shower plate 34 and the end surface 37a of the insulating member 37. The through holes 38a, 39a, 34b and the threaded hole 32c are connected to each other, and the metal fastening screw 41 is inserted into the formed connecting holes.

[0085] The fastening screw 41 includes a screw head 42 and a screw shaft 43. A distal end of the screw shaft 43 is provided with a protruding thread 43a having a diameter reduced compared to the general portion of the screw shaft 43. The fastening screw 41 is inserted through the communication hole formed by the through holes 38a, 39a, and 34b, and the protruding thread 43a is screwed into the threaded hole 32c. As a result, the first cover member 38 and the second cover member 39 are fastened to the metal window unit 31 via the fastening screw 41.

[0086] The screw head 42 of the fastening screw 41 is covered by a screw cover 44. The screw cover 44 includes a first metal base 45 that contacts the screw head 42, and a first protective film 46 composed of a ceramic spray film that covers at least a portion of the surface of the first base 45. Here, "at least a portion of the surface of the first base 45" refers to at least the surface of the first base 45 that is exposed to the processing chamber S and the plasma.

[0087] A first thread groove 42a is formed on the side of the screw head 42. Meanwhile, the first base 45 of the screw cover 44 has a recess 45a, and a second thread groove 45b is formed on the wall of the recess 45a. By screwing the first thread groove 42a and the second thread groove 45b together, the screw cover 44 is secured to the screw head 42 with the recess 45a covering the screw head 42.

[0088] As described above, the first cover member 38 and the second cover member 39 stacked on each other cover the exposed surface 34a of the shower plate 34 and the end surface 37a of the insulating member 37, and are fastened to the metal window unit 31 via the fastening screws 41. Furthermore, the screw cover 44 covers the screw head 42 of the fastening screw 41, thereby forming the fastening structure 40.

[0089] Here, the first base 45 is formed of a non-magnetic and conductive metal, such as aluminum or an aluminum alloy, stainless steel, etc., similarly to the metal window unit 31. In particular, stainless steel having good corrosion resistance to halogen gases such as BCl3 (boron trichloride) gas and Cl2 (chlorine) gas, which are etching gases, is preferably used in consideration of corrosion resistance.

[0090] On the other hand, the first protective film 46 is formed of a ceramic sprayed film having high plasma resistance. As the ceramic, a ceramic containing yttrium can be used. As the yttrium-containing ceramic, any one of Y2O3 (yttrium oxide), YOF (yttrium oxyfluoride), YF3 (yttrium fluoride), or a mixture thereof can be used. Alternatively, a sprayed film may be formed by mixing a ceramic other than a yttrium-containing ceramic with a yttrium-containing ceramic.

[0091] Furthermore, by forming the surface of the first protective film 46 into a sprayed surface with a surface roughness of approximately 7 μm, the first protective film 46 improves its ability to capture deposits, effectively suppressing the peeling of deposits. Furthermore, "deposits" refer to deposits such as precursor gases introduced during plasma processing in the plasma processing apparatus 100 or reaction byproducts generated.

[0092] In the existing fastening structure, a ceramic screw cover (ceramic cover) covers the screw head of a metal fastening screw. The ceramic cover is used to protect the screw head of the fastening screw from being affected by plasma. The ceramic cover is not conductive, so no vertical electric field is generated in the ceramic cover. In addition, the electric field generated by the screw head covered by the ceramic cover is also difficult to pass through the ceramic cover, and even if it does pass through, it becomes very weak. Therefore, although the ceramic cover protects the screw head of the fastening screw from being affected by plasma, deposits are also easily attached to the surface of the ceramic cover. Due to the peeling of deposits attached to the surface of the ceramic cover, particles may be generated.

[0093] Therefore, in the fastening structure 40, by utilizing a screw cover 44 having a first base 45 made of metal in contact with the screw head 42 and a first protective film 46 made of ceramic covering at least the surface of the first base 45 exposed to the plasma, the screw cover 44 can be formed to have the same potential as the metal window unit 31 via the fastening screw 41.

[0094] Because the screw cover 44 and the metal window unit 31 are at the same potential, a vertical electric field is generated on the screw cover 44. The sputtering force generated by the plasma can suppress the adhesion of deposits to the surface of the screw cover 44. The first protective film 46 covering the surface of the screw cover 44 is a ceramic spray film made of an insulating material. Due to the thin thickness of the ceramic spray film, the electric field generated by the first base 45 has sufficient strength to penetrate the ceramic spray film and attract the plasma. Furthermore, since the adhesion of deposits can be suppressed, the particles caused by the peeling of deposits can be reduced. In addition, the reduction in particles can extend the maintenance cycle of the plasma processing device 100.

[0095] Here, a method for forming the fastening structure 40 (fastening method according to the embodiment) will be outlined.

[0096] This fastening method involves fastening a cover member disposed across the exposed surfaces of multiple metal components disposed within a processing chamber 20 generating plasma and having exposed surfaces exposed to the plasma. Here, the exposed surfaces exposed to the plasma are, for example, the exposed surface 34a of the shower plate 34. Furthermore, the multiple metal components are, for example, the multiple metal window units 31. Furthermore, the cover member is, for example, a first cover member 38 and a second cover member 39 made of ceramic, stacked one on top of the other.

[0097] In this method, a metal member such as the metal window unit 31 has a threaded hole (eg, the threaded hole 32 c of the conductor plate 32 ), and the first and second covering members 38 and 39 have insulating properties and through-holes 38 a and 39 a .

[0098] The fastening method includes a step of passing a metal fastening screw 41 having a screw head 42 through the through-holes 38 a and 39 a and screwing it into the threaded hole 32 c to fasten the covering members 38 and 39 to the metal window unit 31 as a metal member.

[0099] The fastening method includes a step of covering the screw head 42 with a screw cover 44 having a metallic first base 45 and a first protective film 46 composed of a ceramic spray film covering at least a portion of the surface of the first base 45 .

[0100] According to this fastening method, a fastening structure 40 can be formed that can suppress the adhesion of deposits to the surface of the screw cover 44 and can reduce particles caused by peeling of deposits.

[0101] [Second Embodiment Fastening Structure]

[0102] Next, refer to Figure 5 , an example of the fastening structure of the second embodiment is described. Here, Figure 5 is with Figure 4 The corresponding drawing is a longitudinal sectional view of an example of the fastening structure according to the second embodiment.

[0103] Figure 5 The illustrated fastening structure 40A differs from the fastening structure 40 in that the second cover member 39A includes a metallic second base 39B in contact with the first cover member 38 and the first base 45, and a second protective film 39C formed of a ceramic sprayed film that covers at least a portion of the surface of the second base 39B. Here, "at least a portion of the surface of the second base 39B" refers to at least the surface of the second base 39B that is exposed to the processing chamber S and the plasma.

[0104] The second base portion 39B, like the metal window unit 31, is formed of a non-magnetic and conductive metal, namely, aluminum or an aluminum alloy, stainless steel, etc. Among them, stainless steel having good corrosion resistance to halogen gases such as BCl3 (boron trichloride) gas and Cl2 (chlorine) gas, which are etching gases, is preferably used in consideration of corrosion resistance.

[0105] On the other hand, the second protective film 39C is formed of a ceramic sprayed film having high plasma resistance. As the ceramic, a ceramic containing yttrium can be used. As the yttrium-containing ceramic, any one of Y2O3 (yttrium oxide), YOF (yttrium oxyfluoride), YF3 (yttrium fluoride), or a mixture thereof can be used. Alternatively, a sprayed film may be formed by mixing a ceramic other than a yttrium-containing ceramic with a yttrium-containing ceramic.

[0106] According to the fastening structure 40A, the metal second base 39B constituting the second cover member 39A contacts the metal first base 45 constituting the screw cover 44, or the screw head 42 screwed to the first base 45. This allows the second cover member 39A and the screw cover 44 to be at the same potential as the metal window unit 31. This generates a perpendicular electric field between the second cover member 39A and the screw cover 44, and the sputtering force generated by the plasma suppresses the adhesion of deposits to the surfaces of the second cover member 39A and the screw cover 44. This allows the deposit adhesion suppression effect to be applied to a wider range, further enhancing the effect of reducing particles caused by the detachment of deposits.

[0107] [Fastening Structure of Third Embodiment]

[0108] Next, refer to Figure 6 , an example of the fastening structure of the third embodiment is described. Here, Figure 6 It is a longitudinal sectional view of an example of the fastening structure of the third embodiment.

[0109] In the intersection region J, when the cover members 38 and 39A are fixed across adjacent metal window units 31 with two fastening screws, the adjacent metal window units 31 are electrically connected via the second cover member 39A and the two fastening screws 41 because the second cover member 39A is made of metal.

[0110] Therefore, the fastening structure 40B has an insulating member 49 between the screw head 42 of at least one of the two fastening screws 41 located on the left and right of the center line CL and the second covering member 39A.

[0111] According to the fastening structure 40B, when the cover members 38 and 39A are fixed with two fastening screws 41 across the adjacent metal window units 31 , electrical conduction between the adjacent metal window units 31 is eliminated.

[0112] [Fastening Structure of Fourth Embodiment]

[0113] Next, refer to Figure 7 , an example of the fastening structure of the fourth embodiment is described. Here, Figure 7 It is a longitudinal sectional view of an example of the fastening structure according to the fourth embodiment.

[0114] Similar to the fastening structure 40B of the third embodiment, when the cover members 38 and 39A are fixed across adjacent metal window units 31 with two fastening screws in the intersection region J, the adjacent metal window units 31 are electrically connected via the second cover member 39A and the two fastening screws 41 .

[0115] Therefore, the fastening structure 40C is such that a fastening screw 41A having a screw head 42A and a screw shaft 43A formed of insulating material is applied to at least one of the two fastening screws located on the left and right sides of the center line CL (the fastening screw on the right side in the example shown).

[0116] According to the fastening structure 40C, when the cover members 38 and 39A are fixed by the two fastening screws 41 and 41A across the adjacent metal window units 31 , electrical conduction between the adjacent metal window units 31 is eliminated.

[0117] [Fifth Embodiment Fastening Structure]

[0118] Next, refer to Figure 8 , an example of the fastening structure of the fifth embodiment is described. Here, Figure 8 This is a longitudinal sectional view of an example of a fastening structure according to a fifth embodiment.

[0119] The fastening structure of this embodiment is a method in which a spring screw structure is applied to the aforementioned fastening structures 40, 40A, 40B, and 40C. This spring screw structure is a method in which a spring seat 48 having a through hole 48a is arranged at the bottom of the through holes 38a and 39a at a position corresponding to the screw hole 32c, and a coil spring 47 is arranged inside the spring seat.

[0120] The fastening screw 41 passes through the through-hole 48a at the bottom of the coil spring 47 and the spring seat 48, and is tightened by screwing the protruding thread 43a at the tip into the threaded hole 32c. At this time, the spring seat 48 is compressed axially by the screw head 42 toward the screw shaft 43. Furthermore, the screw cover 44 is attached to the spring seat 48, not to the screw head 42.

[0121] A thread groove 48b is provided on the outer side of the upper end of the spring seat 48, and is threadably engaged with a second thread groove 45b provided in the recess 45a of the screw cover 44. The screw head 42 and the screw cover 44 do not directly contact each other.

[0122] The fastening structure 40D having the above-described structure can absorb deformation caused by pressure difference during vacuuming or deformation caused by heat by the coil spring 47 , thereby preventing damage such as cracking of the ceramic covering members 38 , 39 .

[0123] For the structures exemplified in the above embodiments, other embodiments can be formed by combining other constituent elements, and the present invention is not limited to the structures disclosed herein. In this regard, changes can be made without departing from the scope of the present invention and can be appropriately set according to its application.

[0124] For example, the plasma processing device 100 shown in the figure is described as an inductively coupled plasma processing device, but it can also be a plasma processing device of other types. Specifically, it can be exemplified by electron cyclotron resonance plasma (ECP) or helicon wave plasma (HWP), parallel plate plasma (CCP). In addition, microwave excited surface wave plasma (SWP) can be exemplified. These plasma processing devices, including ICP, can independently control the ion flux and ion energy, can freely control the etching shape and selectivity, and can obtain 10 11 to 10 13 cm -3 High electron density.

Claims

1. A fastening structure, characterized in that: include: a plurality of metal parts disposed inside the processing container and having exposed surfaces exposed to the plasma generated inside the processing container and threaded holes; a covering member disposed so as to span the exposed surfaces of the plurality of metal members, having insulating properties and having a through hole; a metal fastening screw having a screw head that penetrates the through hole and is screwed into the threaded hole to fasten the covering member to the metal member; and a screw cover covering the screw head and having a recessed portion, The screw cover comprises: a first base portion made of metal in contact with the screw head; and a first protective film consisting of a ceramic sprayed film covering at least a portion of the surface of the first base, A first thread groove is formed on the side of the screw head. A second thread groove is formed on the wall surface of the recessed portion of the screw cover. The first thread groove and the second thread groove are screwed together, and the fastening screw and the metal component are fastened together, so that the first base portion and the metal component are electrically connected.

2. The fastening structure according to claim 1, wherein: The ceramic sprayed film is formed of ceramic containing yttrium.

3. The fastening structure according to claim 1 or 2, wherein: The ceramic sprayed film covers the surface of the first base portion exposed to the plasma.

4. The fastening structure according to claim 1 or 2, wherein: The recessed portion covers the screw head in a state where the first thread groove and the second thread groove are threadedly engaged with each other.

5. A plasma processing apparatus having a processing container for generating plasma to process a substrate, the plasma processing apparatus comprising: a plurality of metal parts disposed inside the processing container and having exposed surfaces exposed to the plasma and threaded holes; a covering member disposed so as to span the exposed surfaces of the plurality of metal members, having insulating properties and having a through hole; a metal fastening screw having a screw head that penetrates the through hole and is screwed into the threaded hole to fasten the covering member to the metal member; and a screw cover covering the screw head and having a recessed portion, The screw cover comprises: a first base portion made of metal in contact with the screw head; and a first protective film consisting of a ceramic sprayed film covering at least a portion of the surface of the first base, A first thread groove is formed on the side of the screw head. A second thread groove is formed on the wall surface of the recessed portion of the screw cover. The first thread groove and the second thread groove are screwed together, and the fastening screw and the metal component are fastened together, so that the first base portion and the metal component are electrically connected.

6. The plasma processing apparatus according to claim 5, wherein: The ceramic sprayed film is formed of ceramic containing yttrium.

7. The plasma processing apparatus according to claim 5 or 6, wherein: The ceramic sprayed film covers the surface of the first base portion exposed to the plasma.

8. The plasma processing apparatus according to claim 5 or 6, wherein: The processing container comprises: a processing chamber for generating the plasma to process the substrate; and an antenna chamber equipped with an inductively coupled antenna. The metal component is a metal window unit, and a plurality of the metal window units are arranged side by side to form a metal window that separates the processing chamber from the antenna chamber.

9. The plasma processing apparatus according to claim 8, wherein: A plurality of the metal window units are separated by insulating members, The covering member covers the insulating member and is arranged across the exposed surfaces of the plurality of metal window units.

10. The plasma processing apparatus according to claim 9, wherein: The covering member includes a first covering member made of ceramic and a second covering member stacked on the first covering member. The first covering member covers the insulating member, The second covering member includes: a second metal base in contact with the first covering member and the first base; and a second protective film consisting of a ceramic sprayed film covering at least a portion of the surface of the second base. The second covering member covers the plurality of first covering members in an intersection region where the plurality of first covering members intersect. The fastening screws pass through the respective through holes of the first cover member and the second cover member and are screwed into the threaded holes of the metal window unit, thereby fastening the first cover member and the second cover member to the metal window unit.

11. A fastening method for fastening a covering member to a plurality of metal members, wherein: A plurality of metal components are disposed inside a processing container and have exposed surfaces exposed to plasma generated inside the processing container. The cover member is disposed so as to span the exposed surfaces of the plurality of metal components. The fastening method is characterized by: The metal component has a threaded hole, and the covering component has insulating properties and a through hole. The fastening method comprises: a step of passing a metal fastening screw having a screw head through the through hole and screwing the screw screw into the threaded hole to fasten the covering member to the metal member; and The step of covering the screw head with a screw cover, wherein the screw cover has a first base made of metal, a first protective film consisting of a ceramic spray film covering at least a portion of the surface of the first base, and a recessed portion, A first thread groove is formed on the side of the screw head. A second thread groove is formed on the wall surface of the recessed portion of the screw cover. The first base portion and the metal component are electrically connected by screwing the first thread groove and the second thread groove together and fastening the fastening screw and the metal component together.

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