Fastening structure, plasma processing device, and fastening method

Abstract

The present invention relates to a fastening structure, a plasma processing device, and a fastening method. In a fastening structure for fastening components constituting a substrate processing device to each other using a fastening screw, the fastening screw is prevented from loosening. A fastening structure fastens a first component and a second component constituting a substrate processing device, wherein the first component has an internal thread portion, the second component has a through hole corresponding to the internal thread portion, and a countersunk portion continuous with the through hole and having a diameter larger than the diameter of the through hole, the fastening structure comprising: a fastening screw having an external thread portion passing through the through hole and threadedly coupled to the internal thread portion, and a screw head continuous with the end of the external thread portion; and a flat washer engaged in the countersunk portion for the external thread portion to pass through, at least one or both of a first surface of the screw head opposite to the flat washer and a second surface of the flat washer opposite to the screw head being covered with a lubricating material.

Description

Technical Field

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

[0002] Patent Document 1 discloses a plasma processing apparatus that performs plasma processing on a glass substrate within a vacuum-exhausted processing space using a plasma-converted processing gas. The plasma processing apparatus comprises a metal processing container including a mounting table for mounting the glass substrate, the upper surface of the processing container being open and electrically grounded, a metal window comprising a plurality of conductive partial windows arranged to close the opening of the processing container and form a processing space, and a plasma antenna disposed above the metal window, facing the metal window, for converting the processing gas into plasma through inductive coupling. In the plasma processing apparatus of Patent Document 1, each partial window of the metal window also serves as a showerhead for supplying the processing gas. Furthermore, each partial window is constructed by stacking a shower plate and a metal window body, starting from the bottom. The shower plate is formed with a plurality of processing gas ejection holes for supplying the processing gas into the processing space, and the metal window body forms a processing gas diffusion chamber between the shower plate and the metal window body for diffusing the processing gas. Furthermore, in the plasma processing apparatus of Patent Document 1, the shower plate is fastened to the metal window body by screws, and a temperature control flow path through which a temperature control fluid for temperature control flows is formed in the metal window body.

[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] According to the technology disclosed in the present invention, in a fastening structure in which members constituting a substrate processing apparatus are fastened to each other using fastening screws, loosening of the fastening screws is prevented.

[0008] Solutions for solving problems

[0009] A technical solution disclosed herein is a fastening structure, which fastens a first component and a second component constituting a substrate processing device, wherein the first component has an internal threaded portion, and the second component has a through hole corresponding to the internal threaded portion and a countersunk portion continuous with the through hole and having a diameter larger than the diameter of the through hole, the fastening structure comprising: a fastening screw having an external threaded portion that passes through the through hole and is threadedly engaged with the internal threaded portion, and a screw head continuous with an end portion of the external threaded portion; and a flat washer that is engaged with the countersunk portion for the external threaded portion to pass through, at least either one or both of a first surface of the screw head opposite to the flat washer and a second surface of the flat washer opposite to the screw head being covered with a lubricating material.

[0010] Effects of the Invention

[0011] According to the present disclosure, in a fastening structure in which members constituting a substrate processing apparatus are fastened to each other using fastening screws, loosening of the fastening screws can be prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a longitudinal sectional view schematically showing the structure of the plasma processing apparatus according to this embodiment.

[0013] Figure 2 This is a bottom view of the metal window described later.

[0014] Figure 3 yes Figure 1 A partial enlarged view of .

[0015] Figure 4 Yes Figure 1 A schematic longitudinal sectional view of the structure of the fastening structure of the plasma processing device is equivalent to Figure 3 Inverted and partially enlarged image.

[0016] Figure 5 It is a longitudinal sectional view showing another example of the fastening structure.

[0017] Figure 6 It is a longitudinal sectional view showing another example of the fastening structure.

[0018] Figure 7 It is a longitudinal sectional view showing another example of the fastening structure.

[0019] Figure 8 It is a figure which shows the result of a confirmation test.

[0020] Figure 9 It is a figure which shows the result of a confirmation test.

[0021] Figure 10 It is a figure which shows the result of a confirmation test. DETAILED DESCRIPTION

[0022] In the manufacturing process of flat panel displays (FPDs) such as liquid crystal displays (LCDs), substrates such as glass substrates are subjected to substrate processing such as etching and film formation. These substrate processing processes use substrate processing apparatuses having processing containers for accommodating the substrates being processed.

[0023] In addition, as a substrate processing apparatus, there is a plasma processing apparatus that processes a substrate using plasma of a processing gas, and as a plasma processing apparatus, there is an apparatus that uses inductively coupled plasma (see Patent Document 1).

[0024] As described above, the plasma processing apparatus using inductively coupled plasma disclosed in Patent Document 1 includes a metal processing container having a mounting table for mounting a glass substrate. The processing container has an open top surface opposite the mounting table and is electrically grounded. Furthermore, the plasma processing apparatus disclosed in Patent Document 1 includes a metal window comprising a plurality of conductive partial windows arranged to close the opening of the processing container and form a processing space; and a plasma antenna disposed above the metal window, facing the metal window, for converting a processing gas into plasma using inductive coupling. In the plasma processing apparatus disclosed in Patent Document 1, each partial window of the metal window also serves as a showerhead for supplying processing gas. Furthermore, each partial window is constructed by sequentially stacking a shower plate and a metal window body from below. The shower plate is formed with a plurality of processing gas ejection holes for supplying processing gas into the processing space. The metal window body forms a processing gas diffusion chamber between the metal window and the shower plate for diffusing the processing gas. Furthermore, in the plasma processing apparatus of Patent Document 1, the shower plate is fastened to the metal window body by screws, and a temperature control flow path through which a temperature control fluid for temperature control flows is formed in the metal window body.

[0025] Furthermore, in a plasma processing apparatus, when screws are used to fasten the shower plate and the metal window body as disclosed in Patent Document 1, the screws may become loose due to substrate processing or repeated substrate processing.

[0026] The cause of the screw loosening is believed to be the difference in thermal expansion between the shower plate and the metal window body. Specifically, the shower plate receives heat input from the process gas plasma. Furthermore, while temperature control is performed, this temperature control is performed via the metal window body. Consequently, the shower plate reaches a high temperature and expands. In contrast, the metal window body is directly temperature-controlled using a temperature control flow path, resulting in minimal temperature fluctuations and no expansion. Consequently, it is believed that the shower plate slides along the metal window body, exerting a force on the screw, which in turn causes the screw to loosen.

[0027] Moreover, if the screws fastening the shower plate and the metal window body become loose, the following problems may arise: corrosion due to the process gas reaching unnecessary parts, generation of particles caused by corrosion, and poor electrical conduction and heat transfer between the shower plate and the metal window body.

[0028] Furthermore, in substrate processing apparatuses other than plasma processing apparatuses, if screws fastening components constituting the substrate processing apparatus become loose, this may adversely affect substrate processing and the like.

[0029] Therefore, the technology disclosed herein prevents the fastening screws from loosening in a fastening structure in which members constituting a substrate processing apparatus are fastened to each other using the fastening screws.

[0030] Hereinafter, the fastening structure, plasma processing apparatus, and fastening method of this embodiment will be described with reference to the accompanying drawings. In addition, in this specification and the accompanying drawings, elements having substantially the same functional configuration are denoted by the same reference numerals to omit repeated description.

[0031] <Plasma processing device 1>

[0032] Figure 1 It is a longitudinal sectional view schematically showing the structure of the plasma processing apparatus according to this embodiment.

[0033] Figure 2 This is a bottom view of the metal window described later. Figure 3 yes Figure 1 A partial enlarged view of .

[0034] Figure 1 A plasma processing apparatus 1 performs substrate processing, or plasma treatment, using plasma generated by a processing gas on a rectangular glass substrate G (hereinafter referred to as "substrate G"). Examples of plasma treatments performed by the plasma processing apparatus 1 include film formation, etching, and ashing for FPDs. These processes form electronic devices such as light-emitting elements and their driver circuits on substrate G.

[0035] The plasma processing apparatus 1 includes a rectangular cylindrical container body 10. The container body 10 is formed from a conductive material, such as aluminum, and is electrically grounded. Corrosive gases are often used in plasma processing, so the inner wall of the container body 10 is treated with a corrosion-resistant coating, such as anodizing, to improve corrosion resistance. Furthermore, an opening is formed on the upper surface of the container body 10. This opening is hermetically sealed by a rectangular metal window 20 insulated from the container body 10. Specifically, the opening is hermetically sealed by the metal window 20 and a metal frame 14 (described later). The space enclosed by the container body 10 and the metal window 20 constitutes a processing space S1, where substrates G, the target of plasma processing, are located during plasma processing. The space above the metal window 20 constitutes an antenna chamber S2, where a high-frequency antenna (plasma antenna) 80 (described later) is located. A sidewall of the container body 10 includes an inlet / outlet port 11 for loading and unloading substrates G into and out of the processing space S1, and a gate valve 12 for opening and closing the inlet / outlet port 11.

[0036] A substrate support 30 for supporting the substrate G is provided below the processing space S1 so as to face the metal window 20 . The substrate support 30 includes a main body 31 for placing the substrate G thereon. The main body 31 is provided on the bottom surface of the container body 10 via legs 32 .

[0037] The main body 31 is made of a conductive material, such as aluminum. The surface of the main body 31 is coated with a coating such as anodizing or ceramic spraying to improve insulation and corrosion resistance. Furthermore, an electrostatic chuck (not shown) is provided on the main body 31 to hold the substrate G by suction.

[0038] Furthermore, a high-frequency power supply 41 is connected to the main body 31 via a matching unit 40. The high-frequency power supply 41 supplies high-frequency power for bias, for example, high-frequency power with a frequency of 3.2 MHz, to the main body 31. This allows ions in the plasma generated in the processing space S1 to be drawn toward the substrate G.

[0039] Furthermore, a cooling mechanism is provided within the main body 31 as a temperature control mechanism for regulating the temperature of the substrate G. This cooling mechanism includes a refrigerant flow path (not shown) for circulating a refrigerant for cooling the substrate G. A heating mechanism (e.g., a resistance heater) may be provided as the temperature control mechanism instead of the cooling mechanism, or both a cooling mechanism and a heating mechanism may be provided. Furthermore, a temperature sensor (not shown) and a gas flow path (not shown) for supplying a heat transfer gas, such as He gas, to the back surface of the substrate G are provided within the main body 31.

[0040] An exhaust port 13 is formed on the bottom surface of the container body 10. An exhaust unit 50 including a vacuum pump or the like is connected to the exhaust port 13. The processing space S1 is depressurized by the exhaust unit 50. The exhaust unit 50 may be provided for each of the multiple exhaust ports 13 or may be provided in common for the multiple exhaust ports 13.

[0041] A metal frame 14, which is a rectangular frame formed of a metal material such as aluminum, is provided on the upper surface of the side wall of the container body 10. A sealing member 15 is provided between the container body 10 and the metal frame 14 to maintain the processing space S1 airtight. The container body 10, the metal frame 14, and the metal window 20 constitute a processing container for accommodating substrates G to be processed.

[0042] like Figure 1 and Figure 2 As shown, the metal window 20 is divided into a plurality of partial windows 21 . These partial windows 21 are arranged inside the metal frame 14 , and the metal window 20 as a whole is in a rectangular shape.

[0043] The local windows 21 function as showerheads for supplying processing gas to the processing space S1. Figure 3 As shown, each partial window 21 is constructed by stacking a shower plate 22 (second component) and a metal window body (base component) 23 (first component) in sequence from below. The shower plate 22 is formed with a plurality of gas ejection holes 22a for supplying process gas to the processing space S1. A diffusion chamber 23a is formed between the metal window body 23 and the shower plate 22 to diffuse the process gas.

[0044] The shower plate 22 is fastened to the metal window body 23 by fastening screws 24. In other words, the plasma processing apparatus 1 includes a fastening structure for fastening the shower plate 22 and the metal window body 23 by fastening screws 24. Details of this fastening structure will be described later.

[0045] Specifically, the shower plate 22 is fastened to the lower surface of the metal window body 23 in an area outside the recessed portion forming the diffusion chamber 23a using fastening screws 24. More specifically, the shower plate 22 is fastened to the lower surface of the metal window body 23 in an area between an O-ring 25 and a spiral ring 26, which will be described later, using fastening screws 24.

[0046] In addition, an O-ring 25 for sealing the diffusion chamber 23a is provided between the periphery of the shower plate 22 and the periphery of the metal window body 23, and a spiral ring 26 for electrically connecting the shower plate 22 and the metal window body 23 is provided on the outside of the O-ring 25.

[0047] Partial window 21 having these structures is held on the ceiling side of processing space S1 by a holding portion (not shown).

[0048] like Figure 1 As shown, the diffusion chamber 23a of each local window 21 is connected to the processing gas supply unit 61 via a gas supply pipe 60. The processing gas supply unit 61 includes a flow adjustment valve (not shown), an on-off valve (not shown), etc., and supplies the processing gas required for film formation, etching, ashing, etc. to the diffusion chamber 23a. In addition, for the convenience of illustration, Figure 1 3 shows a state in which the processing gas supply unit 61 is connected to one partial window 21 , but in reality, the processing gas supply unit 61 is connected to the diffusion chamber 23 a of each partial window 21 .

[0049] Moreover, if Figure 1 and Figure 3 As shown, a temperature control flow path 23b for circulating a temperature control fluid for temperature control is formed in the metal window body 23 of each local window 21. The temperature control flow path 23b is connected to a temperature control fluid supply unit (not shown). The temperature control fluid supply unit includes an on-off valve, a pump, etc., which supplies the temperature control fluid to the temperature control flow path 23b. The temperature of the shower plate 22 is adjusted by means of the metal window body 23 using the temperature control fluid. Specifically, based on the temperature detection result of the temperature sensor (not shown) provided in the metal window body 23, the temperature of the shower plate 22 is adjusted by using the temperature control fluid supplied from the above-mentioned temperature control fluid supply unit so as to reach a predetermined temperature. In addition, it is also possible to change the set temperature of the temperature control fluid supply unit according to the processing result of the substrate G instead of using a temperature sensor.

[0050] Each shower plate 22 and each metal window body 23 is made of a non-magnetic, conductive material, such as aluminum. Furthermore, when a corrosive gas is used as a process gas, the lower surface of the shower plate 22 facing the processing space S1, the surfaces of the shower plate 22 and metal window body 23 forming the diffusion chamber 23a, and the inner circumference of the gas ejection holes 22a of the shower plate 22 are treated with a corrosion-resistant coating, such as anodizing, to improve corrosion resistance. Furthermore, the lower surface of the shower plate 22 is treated with a plasma-resistant coating, such as coating with a ceramic, such as yttrium oxide, to improve plasma resistance. Furthermore, the areas outside the O-ring 25 on the upper peripheral surface of the shower plate 22 and the lower peripheral surface of the metal window body 23 are not treated with a corrosion-resistant coating. This is to ensure electrical connection between the shower plate 22 and the metal window body 23 and to facilitate temperature regulation of the shower plate 22 via the metal window body 23.

[0051] In addition, the partial windows 21 are electrically insulated from the metal frame 14 by the insulating member 27, and adjacent partial windows 21 are also electrically insulated from each other by the insulating member 27. An insulating member cover 28 is provided on the insulating member 27 to cover the surface of the insulating member 27 on the processing space S1 side to protect the insulating member 27. Figure 2As shown, the insulating member cover 28 is divided into a plurality of partial covers 28 a , for example.

[0052] In addition, if Figure 3 As shown, the insulating member cover 28 covers the processing space S1 side of the fastening screw 24 to prevent the fastening screw 24 from being exposed to the processing space S1. Specifically, the insulating member cover 28 blocks the counterbore portion that receives the screw head of the fastening screw 24.

[0053] Moreover, if Figure 1 As shown, a top plate portion 70 is disposed above the metal window 20 . The top plate portion 70 is supported by a side wall portion 71 provided on the metal frame 14 .

[0054] The space enclosed by the metal window 20 , the side wall portion 71 , and the top plate portion 70 constitutes an antenna chamber S2 . A high-frequency antenna 80 is disposed within the antenna chamber S2 so as to face the partial window 21 .

[0055] For example, the radio frequency antenna 80 is separated from the partial window 21 by a spacer (not shown) made of an insulating material. Multiple radio frequency antennas 80 are formed along the surfaces corresponding to the partial windows 21, such as in a spiral or concentric pattern, surrounding the circumference of the rectangular metal window 20, thereby forming a multi-ring antenna.

[0056] Each radio frequency antenna 80 is connected to a radio frequency power source 43 via a matching device 42. Radio frequency power, for example, of 13.56 MHz, is supplied from the radio frequency power source 43 via the matching device 42 to each radio frequency antenna 80. Consequently, during plasma processing, eddy currents are induced on the surfaces of each local window 21. These eddy currents form an induced electric field within the processing space S1. The processing gas ejected from the gas ejection holes 22a is converted into plasma within the processing space S1 by the induced electric field.

[0057] Moreover, if Figure 1 As shown, the plasma processing apparatus 1 is provided with a control unit U. The control unit U is, for example, a computer equipped with a CPU, memory, etc., and has a program storage unit (not shown). The program storage unit stores a program for controlling the processing of substrates G in the plasma processing apparatus 1. The program can also be stored in a computer-readable storage medium and loaded from the storage medium into the control unit U. Part or all of the program can also be implemented using dedicated hardware (circuit board).

[0058] <Fastening structure K>

[0059] As described above, in conventional plasma processing apparatuses, when fastening screws are used to fasten the shower plate and the metal window body, the fastening screws may become loose due to repeated substrate processing (specifically, plasma processing). Therefore, the plasma processing apparatus 1 of this embodiment includes the following fastening structure K to prevent the fastening screws 24 from loosening.

[0060] Figure 4 This is a schematic longitudinal sectional view showing the structure of the fastening structure K provided in the plasma processing apparatus 1, which is equivalent to Figure 3 Upside-down and partially enlarged image.

[0061] Figure 4 The fastening structure K includes a fastening screw 24 , a flat washer 120 , an internal thread portion 100 provided on the metal window body 23 , a through hole 110 and a countersunk portion 111 provided on the shower plate 22 .

[0062] The internal thread portion 100 is constituted by, for example, an insert 101 having an internal thread and embedded in the metal window body 23. The insert 101 is, for example, a spiral member formed by winding a wire having a rhombus cross section.

[0063] For example, the internal thread portion 100 is formed as follows: Specifically, a bottom hole formed on the shower plate 22 side of the metal window body 23 is tapped, and the insert 101 as the spiral member is screwed into the bottom hole to form the internal thread portion 100 .

[0064] The insert 101 is made of a material having higher rigidity than the metal window main body 23. When aluminum is used as the material of the metal window main body 23, stainless steel is used as the material of the insert 101, for example.

[0065] The through hole 110 is formed at a position corresponding to the internal thread portion 100 on the metal window main body 23 side of the shower plate 22 .

[0066] The counterbore portion 111 is formed in the shower plate 22 so as to be continuous with the through-hole 110. Specifically, the counterbore portion 111 is formed so as to be recessed from the surface of the shower plate 22 on the side opposite to the metal window body 23 along the penetration direction of the through-hole 110 and to be continuous with the side of the through-hole 110 opposite to the metal window body 23.

[0067] The fastening screw 24 includes an external thread portion 24a that passes through the through-hole 110 and is threadedly engaged with the internal thread portion 100, and a screw head 24b that is continuous with the base end of the external thread portion 24a. The diameter of the through-hole 110 is set so that only the external thread portion 24a of the fastening screw 24 can be inserted into the through-hole 110, and the screw head 24b cannot be inserted. In addition, the diameter of the counterbore portion 111 is set so that not only the external thread portion 24a of the fastening screw 24 can be inserted, but also the screw head 24b. The diameter of the external thread portion 24a is, for example, 3 mm to 7 mm, and the diameter of the screw head 24b is, for example, 6 mm to 15 mm.

[0068] The flat washer 120 is fitted into the counterbore 111 of the shower plate 22 and is penetrated by the external thread 24a of the fastening screw 24. Specifically, the flat washer 120 has a hole in the center through which only the external thread 24a of the fastening screw 24 can pass. The flat washer 120 has an outer diameter that fits the counterbore 111.

[0069] As described above, the flat washer 120 is fitted into the counterbore portion 111 of the shower plate 22. Therefore, when the through-hole 110 and counterbore portion 111 of the shower plate 22 move relative to the internal thread 100 of the metal window body 23, the flat washer 120, along with the counterbore portion 111 and the like, moves relative to the internal thread 100. At this time, if the friction between the screw head 24b and the flat washer 120 is high, this friction may become torque, exerting a rotational force on the screw head 24b, potentially loosening the fastening screw 24. Furthermore, the diameter of the central hole in the flat washer 120, through which the external thread 24a passes, is set so that the flat washer 120 does not collide with the external thread 24a of the fastening screw 24 during relative movement.

[0070] Furthermore, in the fastening structure K, either or both of the first surface 24c of the screw head 24b, which faces the flat washer 120, and the second surface 120a of the flat washer 120, which faces the screw head 24b, are coated with a lubricant. In other words, either or both of the first surface 24c and the second surface 120a are coated with a lubricant. This reduces the frictional force acting between the flat washer 120 and the fastening screw 24.

[0071] The lubricating material coating is, for example, a coating of chemical nickel plating containing polytetrafluoroethylene (PTFE).

[0072] In the fastening structure K, when the external thread portion 24 a of the fastening screw 24 is screwed into the internal thread portion 100 via the flat washer 120 and the through hole 110 to fasten the fastening screw 24 , the shower plate 22 can be fastened to the metal window body 23 by the fastening screw 24 .

[0073] Function of the fastening structure K

[0074] Next, the function of the fastening structure K of the plasma processing apparatus 1 will be described.

[0075] In the plasma processing apparatus 1, the shower plate 22 receives heat input from the plasma of the process gas. While temperature control is performed, this control is performed via the metal window body 23. Therefore, the shower plate 22 reaches a high temperature during plasma processing, causing it to expand. In contrast, the metal window body 23 receives no direct heat input from the plasma of the process gas. Furthermore, temperature control is performed directly via the temperature control flow path 23b, resulting in the metal window body 23 maintaining a relatively constant temperature during plasma processing and preventing expansion. Consequently, the relative positions of the internal threaded portion 100 of the metal window body 23 and the through-hole 110 and counterbore portion 111 of the shower plate 22 differ during plasma processing compared to outside of plasma processing. In other words, during plasma processing, the through-hole 110 and counterbore portion 111 move relative to the internal threaded portion 100 and also relative to the fastening screw 24 mounted thereon.

[0076] Unlike the fastening structure K, when the flat washer has a smaller outer diameter than when fitted with the counterbore portion 111, that is, when the flat washer is movable within the counterbore portion 111, even when the through-hole 110 and the counterbore portion 111 move relative to the fastening screw 24, the flat washer does not move sufficiently relative to the fastening screw 24. Consequently, the flat washer moves relative to both the fastening screw 24 and the counterbore portion 111, potentially causing a greater degree of variation in the manner in which the fastening force between the fastening screw 24, the metal window body 23, and the flat washer is applied. This variation in the fastening force associated with the movement of the flat washer could potentially cause the fastening screw 24 to loosen.

[0077] In contrast, in fastening structure K, as described above, the flat washer 120 is fitted into the counterbore portion 111. Therefore, when the through-hole 110 and the counterbore portion 111 move relative to the fastening screw 24, the flat washer 120 and the counterbore portion 111 move relative to the fastening screw 24. Therefore, the flat washer 120 is fixed within the counterbore portion 111, and the mutual force application pattern remains unchanged. The screw head 24b of the fastening screw 24 moves on the stable surface of the flat washer 120, resulting in minimal changes in the mutual force application pattern. Consequently, the fastening screw 24 is less likely to loosen due to changes in the tightening force associated with the movement of the flat washer 120.

[0078] Furthermore, in the fastening structure K, either or both the first surface 24c of the fastening screw 24 and the second surface 120a of the flat washer 120 are coated with a lubricating material. Therefore, when the flat washer 120 moves relative to the fastening screw 24, that is, when the flat washer 120 slides on the first surface 24c of the screw head 24b, the frictional force acting between the flat washer 120 and the screw head 24b of the fastening screw 24 is small. Consequently, the fastening screw 24 is prevented from loosening due to this frictional force.

[0079] Therefore, according to the fastening structure K, it is possible to prevent the fastening screw 24 from becoming loose.

[0080] Substrate processing

[0081] Next, substrate processing by the plasma processing apparatus 1 will be described.

[0082] First, the gate valve 12 is opened, and the substrate G is carried into the processing space S1 through the carry-in / out port 11 and placed on the substrate support 30. Then, the gate valve 12 is closed.

[0083] Next, the processing gas is supplied from the processing gas supply unit 61 into the processing space S1 through the diffusion chamber 23a of each local window 21. The processing space S1 is exhausted by the exhaust unit 50 to adjust the pressure in the processing space S1 to a desired level.

[0084] Next, high-frequency power is supplied from the high-frequency power supply 43 to the high-frequency antenna 80, thereby generating an induced electric field within the processing space S1 via the metal window 20. As a result, the induced electric field converts the processing gas within the processing space S1 into plasma, generating a high-density inductively coupled plasma. Subsequently, high-frequency bias power supplied from the high-frequency power supply 41 to the main body 31 of the substrate support 30 draws ions from the plasma toward the substrate G, thereby performing plasma processing on the substrate G.

[0085] After the plasma processing is completed, the power supply from the high frequency power supplies 41 and 43 and the supply of the processing gas from the processing gas supply unit 61 are stopped, and the substrate G is carried out in the reverse order of the introduction.

[0086] Thus, a series of substrate processing is completed.

[0087] During the aforementioned series of substrate processing, including during plasma processing, the shower plate 22 of each local window 21 is temperature-controlled using a temperature-control fluid supplied to the temperature-control flow path 23b. However, during the plasma processing, the shower plate 22 experiences heat input from the plasma, causing it to reach a high temperature and expand. Consequently, the through-hole 110 and the counterbore portion 111 of the shower plate 22 move relative to the fastening screw 24. However, in the plasma processing apparatus 1, the flat washer 120 is engaged with the counterbore portion 111, and either or both of the first surface 24c of the fastening screw 24 and the second surface 120a of the flat washer 120 are coated with a lubricant. Therefore, the aforementioned relative movement does not generate significant friction between the flat washer 120 and the screw head 24b of the fastening screw 24, preventing the fastening screw 24 from loosening.

[0088] As described above, according to the present embodiment, in the fastening structure in which the shower plate 22 and the metal window main body 23 constituting the plasma processing apparatus 1 are fastened together by the fastening screws 24 , loosening of the fastening screws 24 can be prevented.

[0089] If the fastening screws 24 become loose, for example, the airtightness of the diffusion chamber 23a achieved by the O-ring 25 is reduced, potentially allowing the process gas to reach between the periphery of the shower plate 22 and the periphery of the metal window body 23. In this case, as described above, areas of the periphery of the shower plate 22 and the periphery of the metal window body 23 are not coated with a corrosion-resistant coating. Therefore, if corrosive gases are used as process or cleaning gases, these areas may corrode. This results in the generation of particles that can cause defects in electronic devices formed on the substrate G, and disrupts electrical continuity and heat transfer between the shower plate 22 and the metal window body 23. If heat transfer between the shower plate 22 and the metal window body 23 is disrupted, the temperature of only the multiple partial windows 21 that constitute the metal window 20 increases, resulting in temperature variations within the surface of the metal window 20. Consequently, the plasma of the process gas also varies, potentially preventing the desired plasma processing.

[0090] Furthermore, if the airtightness of the diffusion chamber 23 a decreases, the spiral ring 26 may be corroded, resulting in the generation of particles and the like.

[0091] According to this embodiment, the fastening screw 24 is prevented from loosening, so the airtightness of the diffusion chamber 23a is not reduced, thereby preventing the generation of the above-mentioned particles. In addition, the electrical conduction between the shower plate 22 and the metal window body 23 and the heat transfer between the two components can be prevented from being destroyed.

[0092] Modifications

[0093] In the above example, either or both of the first surface 24c of the fastening screw 24 and the second surface 120a of the flat washer 120 are covered with a lubricant. The portion covered with the lubricant is not limited thereto; for example, the entire fastening screw 24 or the entire flat washer 120 may be covered with a lubricant. In other words, in the fastening structure K, at least either or both of the first surface 24c of the fastening screw 24 and the second surface 120a of the flat washer 120 need only be covered with a lubricant.

[0094] Furthermore, in addition to coating either or both of the first surface 24c of the fastening screw 24 and the second surface 120a of the flat washer 120 with lubricant, coating the external threaded portion 24a of the fastening screw 24 with lubricant also provides the following advantages. Specifically, the friction between the external threaded portion 24a and the internal threaded portion 100 is reduced, thereby reducing the amount of force opposing the friction in the tightening torque. This allows for more reliable fastening of the shower plate 22 and the metal window body 23 even when the fastening screw 24 is tightened with the same tightening torque. Consequently, loosening of the fastening screw 24 due to insufficient tightening force of the fastening screw 24 relative to the metal window body 23 can be prevented.

[0095] Figures 5 to 7 It is a longitudinal sectional view showing another example of the fastening structure.

[0096] exist Figure 5 In the fastening structure K1, the internal thread portion 100 is formed by an insert 200 with a locking function (i.e., a loosening prevention function). The insert 200 is, for example, a helical member formed by winding a wire with a rhombus cross-section, with the central portion being wound into a polygonal shape. When the external thread portion 24a of the fastening screw 24 is screwed in, the polygonal wire expands, and the reaction force of this expansion tightens the external thread portion 24a, thereby preventing the fastening screw 24 from loosening.

[0097] Furthermore, when the insert 200 is used, the external thread portion 24a of the fastening screw 24 may be covered with a lubricant in advance. This can prevent the external thread portion 24a from being heated and seizure when being screwed in.

[0098] exist Figure 6In the fastening structure K2, the fastening screw 210 is a flanged bolt, and its screw head 211 has a flange 212 at the side end of the external thread portion 24a. Therefore, in the fastening structure K2, the contact area between the first surface 211a of the fastening screw 210 and the second surface 120a of the flat washer 120 is large. This allows the pressure applied to the first and second surfaces 211a, 120a to be dispersed, that is, the pressure per unit area applied to the first and second surfaces 211a, 120a can be reduced. As a result, damage and deformation caused by the excessive stress applied to the fastening screw 24 and flat washer 120 due to locally high pressure can be suppressed, preventing the screw from being unable to rotate due to deformation during installation and removal.

[0099] Figure 7 The fastening structure K3 is similar to the bolt cover 130 except that it uses a flat washer portion 131 and a side wall portion (side wall member) 132. Figure 6 Similarly, in the fastening structure K2, a flange bolt is used as the fastening screw 210.

[0100] The side wall portion 132 is cylindrical and is provided so as to engage with the upper portion of the peripheral end of the flat washer portion 131, i.e., the side into which the fastening screw 210 is inserted. The inner diameter of the side wall portion 132 is larger than the outer diameter of the flange 212 of the fastening screw 210, and the outer diameter of the side wall portion 132 is smaller than the inner diameter of the counterbore portion 111.

[0101] The flat washer portion 131 is joined to the side wall portion 132 at the peripheral end. Figure 6 The fastening structure K2 is the same as the flat washer 120. That is, Figure 6 The flat washer 120 of the fastening structure K2 serves as a flat washer portion 131 , and together with a side wall portion 132 joined to a peripheral edge portion of the flat washer 120 , constitutes a bolt cover 130 .

[0102] The bolt cover 130 has a recess 140 formed in the thickness direction of the flat washer portion 131 by the side wall portion 132 and the flat washer portion 131. When the bolt cover 130 is mounted on the fastening screw 210 and the external thread portion 24a is inserted into the flat washer portion 131, the screw head 211 of the fastening screw 210 is accommodated in the recess 140.

[0103] An anti-dropout ring (anti-dropout member) 133 is disposed inside the side wall portion 132, i.e., inside the recess 140. The anti-dropout ring 133 hooks (i.e., engages) with the flange 212 of the fastening screw 210, thereby preventing the bolt cover 130 attached to the fastening screw 210 from falling off the fastening screw 210. This improves the efficiency of tightening operations using the fastening screw 210.

[0104] Furthermore, the anti-drop ring 133 is, for example, arranged in a contracted state within the recess 140, and is fixed relative to the side wall portion 132 within the recess 140 by the elastic force generated by the contraction. Furthermore, the anti-drop ring 133 is, for example, an elastic member having an inner diameter larger than the outer diameter of the screw head 211 and smaller than the outer diameter of the flange 212, and can be, for example, a C-shaped member formed of a metal material and having a C-shaped shape when viewed from above.

[0105] The side wall portion 132 has a joint end portion that is joined to the flat washer portion 131 and an open end portion that is open on the side opposite to the joint end portion. A step is provided on the inner wall of the side wall portion 132 between the joint end portion and the open end portion for arranging the anti-dropout ring 133. The inner diameter of the side wall portion 132 is smaller from the step portion to the open end portion than from the step portion to the joint end portion, thereby preventing the anti-dropout ring 133 from falling out from the open end portion. After the fastening screw 210 is inserted into the bolt cover 130, the anti-dropout ring 133 is inserted from the upper portion of the bolt cover 130, that is, the open end portion of the side wall portion 132. In addition, as long as the anti-dropout ring 133 can be prevented from falling out, it is not limited to a step and other structures can also be used.

[0106] The above is explained using the process in which a difference in the degree of expansion of the fastened components occurs as an example, but in the process in which a difference in the degree of contraction of the fastened components occurs (specifically, for example, in the process in which the shower plate 22 returns to the temperature before plasma treatment after plasma treatment), according to the technology disclosed in the present invention, it is also possible to prevent the fastening screws from loosening.

[0107] In the above examples, the substrate to be processed by the plasma treatment is a glass substrate, but it may be another substrate such as a semiconductor wafer.

[0108] In the above example, the technology of the present disclosure is used in the fastening structure between the shower plate 22 and the metal window body 23 constituting the plasma processing apparatus 1. However, the technology of the present disclosure can also be applied to other fastening structures using fastening screws in the plasma processing apparatus 1. In addition, the technology of the present disclosure can be applied to structures using fastening screws in substrate processing apparatuses other than plasma processing apparatuses.

[0109] <Confirmation test>

[0110] The present inventors conducted a test to confirm the loosening suppression effect of the fastening screw of the fastening structure disclosed in the present invention.

[0111] In this confirmation test, a rectangular plate (hereinafter referred to as the metal window body dummy) with a recessed bottom surface identical to the one forming the diffusion chamber 23a of the metal window body 23 was fixed to the metal window body dummy. A plate-shaped member (hereinafter referred to as the shower plate dummy) with the same dimensions as the metal window body dummy when viewed from above was fastened to the bottom surface of the metal window body dummy using fastening screws. Multiple air cylinders were then installed along the long sides of the shower plate dummy. After vibrating the shower plate dummy horizontally 100 times in the direction of its short sides, the loosening angle of the fastening screws was measured.

[0112] The metal window body dummy and shower plate dummy were designed to measure approximately 150 mm x 400 mm in plan view, and the amplitude of the shower plate dummy caused by the cylinder was set to approximately 0.5 mm. Furthermore, aluminum was used for the metal window body dummy and shower plate dummy, and fastening screws were installed at six locations: the four corners and the center of each long side of the shower plate dummy. The diameter of the external thread of the fastening screws was 5 mm, and the diameter of the screw head was 8 mm (the diameter of the flange portion was 10 mm if flanged).

[0113] In the test case, the Figure 6 The fastening structure K2 is similar to the fastening structure K2. Specifically, a flange bolt is used as the fastening screw, and a member with a locking function (i.e., a loosening prevention function) is used as the insert. Furthermore, the fastening screw and flat washer are made of stainless steel, and are entirely plated with chemical nickel containing PTFE.

[0114] The fastening structure of Comparative Example 1 adopts Figure 4 The fastening structure of Comparative Example 1 is similar to the fastening structure K. However, in the fastening structure of Comparative Example 1, neither the fastening screw nor the flat washer is covered with lubricant. Furthermore, the flat washer is smaller than that of the test example and does not fit into the countersunk hole. In other words, the fastening structure of Comparative Example 1 is a conventional fastening structure.

[0115] In addition, the fastening structure of Comparative Example 2 adopts Figure 5 The fastening structure of Comparative Example 2 is similar to the fastening structure K of Comparative Example 2. However, in the fastening structure of Comparative Example 2, neither the fastening screw nor the flat washer is covered with lubricating material. Furthermore, the flat washer is smaller than that of the test example and does not fit into the countersunk portion. In other words, the fastening structure of Comparative Example 2 replaces the insert in the fastening structure of Comparative Example 1, which is a conventional fastening structure, with an insert having a locking function.

[0116] Figures 8 to 10 These are graphs showing the loosening angles of the fastening screws at six locations in Comparative Example 1, Comparative Example 2, and Test Example.

[0117] In Comparative Example 1 using the conventional fastening structure, Figure 8 As shown in FIG. 1 , 5 of the 6 fastening screws are loosened by more than 90°, and the remaining one is loosened by 45°. In other words, in the conventional fastening structure, the fastening screws may loosen to a large extent.

[0118] In addition, in Comparative Example 2, Figure 9 As shown in FIG1 , although the degree of loosening of the fastening screws was reduced compared to Comparative Example 1, 5 out of 6 fastening screws loosened by more than 30°. In other words, simply replacing the insert in the conventional fastening structure with an insert having a locking function cannot fully suppress the loosening of the fastening screws.

[0119] In contrast, in the test case, Figure 10 As shown in FIG. 5 , 5 of the 6 fastening screws are not loose at all, and the loose angle of the remaining one is also small, 15°. Thus, according to the fastening structure disclosed in the present invention, loosening of the fastening screws can be suppressed.

[0120] The embodiments disclosed herein are to be considered in all respects as illustrative and non-restrictive, and the embodiments described above may be omitted, replaced, or modified in various forms without departing from the scope of the appended claims and the gist thereof.

Claims

1. A fastening structure for fastening a first member and a second member constituting a substrate processing apparatus, wherein: The first member has an internal thread portion, The second member has a through hole corresponding to the internal thread portion and a counterbore portion continuous with the through hole and having a diameter larger than that of the through hole. The fastening structure comprises: a fastening screw having an external thread portion penetrating the through hole and threadedly engaged with the internal thread portion, and a screw head portion continuous with an end portion of the external thread portion; and a flat washer having an outer diameter fitted into the counterbore portion and having a hole through which the external thread portion passes; A coating of lubricating material is formed on at least one or both of a first surface of the screw head facing the flat washer and a second surface of the flat washer facing the screw head, and the first surface and the second surface are in contact with each other via the coating. The relative positions of the internal thread portion, the through hole, and the counterbore portion are different when the substrate processing apparatus is processing a substrate and when the substrate processing apparatus is not processing the substrate. The diameter of the hole of the flat washer through which the external thread portion passes is set so that the flat washer does not collide with the external thread portion of the fastening screw when the flat washer moves relative to the internal thread portion.

2. The fastening structure according to claim 1, wherein: The screw head of the fastening screw has a flange at a side end of the external thread portion.

3. The fastening structure according to claim 2, wherein: The flat washer serves as a flat washer portion and constitutes a bolt cover together with a cylindrical side wall member joined to the peripheral portion of the flat washer. An anti-falling member is arranged on the inner wall portion of the side wall member, and the anti-falling member engages with the flange to prevent the bolt cover from falling off from the fastening screw.

4. The fastening structure according to claim 1 or 2, wherein: The lubricating material coating is chemical nickel plating containing polytetrafluoroethylene.

5. A plasma processing apparatus for performing plasma processing on a substrate, wherein: The plasma processing apparatus includes a first member and a second member, the first member and the second member being structural members of the plasma processing apparatus and being fastened to each other. The first member has an internal thread portion, The second member has a through hole corresponding to the internal thread portion and a counterbore portion continuous with the through hole and having a diameter larger than that of the through hole. The plasma processing apparatus further comprises: a fastening screw having an external thread portion penetrating the through hole and threadedly engaged with the internal thread portion, and a screw head portion continuous with an end portion of the external thread portion; and a flat washer having an outer diameter fitted into the counterbore portion and having a hole through which the external thread portion passes; A coating of lubricating material is formed on at least one or both of a first surface of the screw head facing the flat washer and a second surface of the flat washer facing the screw head, and the first surface and the second surface are in contact via the coating. The relative positions of the internal thread portion, the through hole, and the counterbore portion are different when the plasma processing apparatus is processing a substrate and when the plasma processing apparatus is not processing the substrate. The diameter of the hole of the flat washer through which the external thread portion passes is set so that the flat washer does not collide with the external thread portion of the fastening screw when the flat washer moves relative to the internal thread portion.

6. The plasma processing apparatus according to claim 5, wherein: The plasma processing apparatus includes a shower head for supplying a processing gas to a processing space where a substrate to be processed by plasma processing is located. The shower head is composed of a base member and a shower plate. The first member is the base member, and the second member is the shower plate.

7. The plasma processing apparatus according to claim 5 or 6, wherein: The screw head of the fastening screw has a flange on one side of the first surface.

8. The plasma processing apparatus according to claim 7, wherein: The flat washer serves as a flat washer portion and constitutes a bolt cover together with a cylindrical side wall member joined to the peripheral portion of the flat washer. An anti-falling member is arranged on the inner wall portion of the side wall member, and the anti-falling member engages with the flange to prevent the bolt cover from falling off from the fastening screw.

9. The plasma processing apparatus according to claim 5 or 6, wherein: The lubricating material coating is chemical nickel plating containing polytetrafluoroethylene.

10. A fastening method for fastening a first member and a second member constituting a substrate processing apparatus, wherein: The first member has an internal thread portion, The second member has a through hole corresponding to the internal thread portion and a counterbore portion continuous with the through hole and having a diameter larger than that of the through hole. The fastening method includes the following steps: disposing a flat washer in the counterbore portion so as to fit in the counterbore portion, wherein the flat washer has an outer diameter that fits in the counterbore portion; and The external thread portion of the fastening screw having a screw head, which is continuous from the screw head, is passed through the hole of the flat washer in the counterbore portion and the through hole and is screwed together with the internal thread portion. A coating of lubricating material is formed on at least one or both of a first surface of the screw head facing the flat washer and a second surface of the flat washer facing the screw head, and the first surface and the second surface are in contact via the coating. The relative positions of the internal thread portion, the through hole, and the counterbore portion are different when the substrate processing apparatus is processing a substrate and when the substrate processing apparatus is not processing the substrate. The diameter of the hole of the flat washer through which the external thread portion passes is set so that the flat washer does not collide with the external thread portion of the fastening screw when the flat washer moves relative to the internal thread portion.

Images