Valve for semiconductor manufacturing device

Abstract

[Project] Provide a valve for semiconductor manufacturing equipment that prevents the valve seat plate from expanding in diameter and maintains overall compactness, provides the necessary thrust to prevent leakage of high-pressure fluids and ensures sealing when the valve is closed, prevents excessive surface pressure on the valve seat plate, improves durability and has excellent corrosion resistance. [Solution] The valve is opened and closed by separating the contact between the diaphragm (6) and the valve seat plate (7) provided in the valve body (1). In the valve body (1), an opening and closing mechanism (8) is provided to close the valve by pressing the diaphragm (6), and a load-distributing member (10) is arranged inside the opening and closing mechanism (8). The load-distributing member (10) is arranged with a predetermined gap (X1) between the connection part of the opening and closing mechanism (8) and the load-distributing member (10) when the valve is open, so as to maintain the thrust generated by the opening and closing mechanism (8) and distribute the sealing load necessary for closing the valve by the valve seat plate (7) and the load-distributing member (10).

Description

Technical Field

[0001] This invention relates to valves for semiconductor manufacturing apparatuses, and more particularly to high-pressure valves suitable for use in situations where fluids such as corrosive gases that adversely affect valve seat sheets flow under high pressure. Prior Technology

[0002] In semiconductor manufacturing processes, various high-pressure fluids containing corrosive gases are frequently used. Valves in semiconductor manufacturing equipment that control these fluids require a strong sealing load when closed to reliably prevent leakage. Therefore, in the case of high-pressure diaphragm valves, the sealing seat liner is easily damaged by this sealing load combined with the corrosiveness of the fluid. Continued use of the valve under these conditions can cause the seat liner to plastically deform and break down, allowing the high-pressure fluid to penetrate its surface or damaged areas, easily leading to the liner's failure. If the liner breaks off, it can block the flow path or cause leakage when the valve is closed.

[0003] To prevent damage to the valve seat sheet, a sheet material with higher yield strength is generally used to increase its strength, or the sealing load on the valve seat sheet when closing the valve is reduced, i.e., the thrust from the support used to press the diaphragm (valve body). Furthermore, increasing the effective area of ​​the valve seat sheet, i.e., the pressure-bearing area of ​​the valve seat sheet from the diaphragm side (the area in contact with the diaphragm), reduces the surface pressure on the valve seat sheet (the load applied per unit area), suppressing this surface pressure to below the pressure resistance of the valve seat sheet material.

[0004] On the other hand, the metal diaphragm valve in Patent Document 1 has a structure in which a buffer body is provided between the valve seat and the drive-side output shaft. When the output shaft is driven in the direction of closing the valve, the output shaft presses the metal diaphragm against the valve seat through the buffer body, thereby attempting to mitigate the impact of the sealing part when closing the valve.

[0005] In the diaphragm valve of Patent Document 2, a thin-film diaphragm made of resin material is provided. A buffer body made of elastic rubber material is assembled on the piston shaft (output shaft) on the drive side, and is located between the piston shaft and the center of the diaphragm. When the piston shaft is driven in the direction of closing the valve, the buffer body is used to reduce the force from the piston shaft.

[0006] However, valves used in semiconductor manufacturing processes are often combined with other valves or control devices in a compact manner. Therefore, such valves require a streamlined size that occupies minimal space in their mounting location. This miniaturization necessitates both miniaturization (shortening the diameter) of the valve mechanism, i.e., the valve seat. Even when the valve is a diaphragm valve, and the pressure-bearing area (contact area) between the valve seat and the diaphragm is reduced due to the shortened diameter of the valve seat, a high level of sealing performance is still required to prevent leakage of high-pressure fluid when the valve is closed. [Previous Technical Documents] [Patent Literature]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 6-94142 [Patent Document 2] Japanese Patent Application Publication No. 2020-63777 Summary of the Invention

[0008] [The problem the invention aims to solve]

[0009] In the aforementioned valves, where a sheet material with high yield strength is used to prevent damage to the valve seat sheet, when the valve is a diaphragm valve, considering the chemical resistance to the fluid, materials commonly used in semiconductor manufacturing, such as fluoropolymers like PCTFE or PFA, are typically used, thus limiting the options. Furthermore, using only such fluoropolymers for the valve seat sheet is insufficient to adequately mitigate the strong sealing load during valve closure, making it difficult to prevent damage to the valve seat sheet.

[0010] On the other hand, in order to reduce the thrust from the branch and thus reduce the force applied to the valve seat plate, the thrust (sealing load) of the branch is reduced. This directly leads to a decrease in the valve's pressure resistance limit, making it difficult to obtain the sealing force necessary to reliably prevent leakage of high-pressure fluids. Therefore, this type of valve is not suitable for situations where the valve is closed to seal high-pressure fluids.

[0011] Furthermore, when increasing the effective area (pressure-bearing area) of the valve seat plate to reduce the surface pressure on the valve seat plate, the valve seat plate is expanded outwards to increase its area in order to maintain a fixed flow path and ensure flow rate. In this case, the increase in the outer diameter of the valve seat plate leads to an increase in the gap between the flow path on one side and the flow path on the other side, resulting in an increase in overall dimensions. In addition, in the case of a diaphragm valve, the outer diameter of the diaphragm also increases, and the thrust of the branch increases to ensure a tight seal for the effective area of ​​the diaphragm.

[0012] Furthermore, the diaphragm valves in Patent Documents 1 or 2, in all cases, have a buffer body arranged in a straight line between the valve seat and the output shaft. During the sealing process when the valve is closed, the buffer body absorbs the thrust from the output shaft side, reducing the force transmitted to the valve seat. Therefore, when such valves are used as high-pressure valves for semiconductor manufacturing, they cannot achieve sufficient sealing performance, and there is a risk of leakage when high-pressure fluid flows.

[0013] Furthermore, regardless of the aforementioned situations, when valves are compactly arranged to accommodate density requirements, the valve seat fin is shortened, resulting in a smaller contact area with the valve body (e.g., the diaphragm). If the sealing area is reduced in this way, a strong thrust corresponding to high-pressure fluid acting from the branch side will exert excessive surface pressure on the valve seat fin, making it prone to damage. If the valve seat fin is damaged beyond its yield strength, it may collapse or break, leading to blockage or leakage in the flow path. For these reasons, in order to allow fluids such as corrosive gases to flow under high pressure when the valve is opened, and to effectively prevent leakage of the high-pressure fluid when the valve is closed, it is necessary to strongly ensure the thrust from the branch side without compromising the sealing performance, and to allow damage to the valve seat fins.

[0014] The present invention was developed to solve the above-mentioned problems and aims to provide a valve for a semiconductor manufacturing apparatus that prevents the valve seat sheet from expanding in diameter and maintains overall compactness, provides the necessary thrust to prevent leakage of high-pressure fluid and ensures sealing when the valve is closed, prevents excessive surface pressure on the valve seat sheet, improves durability and has excellent corrosion resistance. [Technical means to solve the problem]

[0015] To achieve the above objectives, the invention claimed in claim 1 is a valve for a semiconductor manufacturing apparatus that opens and closes by separating a diaphragm and a valve seat sheet disposed on the valve body. The valve body is provided with an opening and closing mechanism for pressing the diaphragm to close the valve. A load-distributing member is disposed inside the opening and closing mechanism. When the valve is open, the load-distributing member is configured such that the connection part of the opening and closing mechanism and the load-distributing member have a predetermined gap, thus forming a dual structure that maintains the thrust generated by the opening and closing mechanism while distributing the sealing load necessary for closing the valve between the valve seat sheet and the load-distributing member.

[0016] The invention claimed in claim 2 includes a load-distributing component located in a part of the flow path that does not come into contact with the fluid in the valve body.

[0017] The claimed invention in claim 3 is a load-dispersing member, which is a ring-shaped load-dispersing sheet made of resin or a disc spring with spring properties.

[0018] In the case of the invention requested in claim 4, if the opening and closing mechanism is an automatic valve, it is composed of a piston or spring of an actuator; if it is a manual valve, it is provided on the support of the handle.

[0019] The claimed invention in claim 5 states that the load-distributing member is positioned such that when the diaphragm contacts the valve seat sheet, it is subjected to a thrust from the piston or spring of the actuator, or from the support of the handle. [Effects of the Invention]

[0020] According to claim 1, the load-distributing member inside the opening / closing mechanism is arranged in parallel with the valve seat sheet. In the open state, the connection point of the opening / closing mechanism and the load-distributing member are positioned with a predetermined gap, creating a dual structure where the sealing load necessary for valve closure is distributed between the valve seat sheet and the load-distributing member. This prevents the valve seat sheet from expanding while maintaining overall compactness by mounting it to the valve body. When the valve is closed, the necessary thrust to prevent leakage of high-pressure fluid ensures a tight seal, and excessive surface pressure on the valve seat sheet improves durability and prevents damage. In this case, the valve seat sheet is made of a resin material with excellent chemical resistance to enhance corrosion resistance, and the load-distributing member, made of an elastic material, distributes the sealing load to ensure durability.

[0021] According to claim 2, a load-dispersing member that applies thrust from the opening and closing mechanism is located in a part that does not come into contact with the fluid in the flow path of the valve body. This makes the load-dispersing member less susceptible to the effects of corrosive gases or heat, thus maintaining its functionality. Therefore, even if the valve seat sheet softens due to corrosive gases or heat, the load-dispersing member can reliably transmit the thrust from the opening and closing mechanism, allowing the load-dispersing sheet to bear the load. This prevents the valve seat sheet from collapsing, causing sinking, a reduction in sealing height, or damage to the valve seat sheet, thereby maintaining excellent sealing performance.

[0022] According to claim 3, the load-dispersing component can be provided by using a ring-shaped load-dispersing sheet made of resin or a coil spring with spring characteristics. By using a resin material such as fluorine resin to provide the load-dispersing sheet, the corrosion resistance or chemical resistance can be improved. Furthermore, by using a coil spring to maintain the thrust of the opening and closing mechanism while easing the load, the durability can be improved.

[0023] According to claim 4, a valve can be provided that uses a piston or spring of an actuator, or an opening and closing mechanism provided on a branch of the valve, thereby corresponding to either an automatic valve or a manual valve, maintaining overall compactness and maintaining the necessary thrust to ensure sealing when the valve is closed.

[0024] According to claim 5, the invention prevents leakage by first contacting the load-distributing member with the piston or spring of the actuator, or with the support provided on the handle, and prevents damage caused by applying load to the valve seat plate first. The thrust generated when the valve is closed is distributed equally between the load-distributing member and the valve seat plate. Therefore, the load on the valve seat plate can be reliably suppressed to below the pressure resistance limit of the material constituting the valve seat plate, or the valve seat plate can be made of a material with lower strength. Simple Explanation of the Diagram

[0025] [Figure 1] shows a central longitudinal cross-sectional view of an embodiment of the valve for a semiconductor manufacturing apparatus according to the present invention. [Figure 2](a) is an enlarged cross-sectional view of the main part of Figure 1. (b) is an enlarged cross-sectional view of the main part showing the closed valve state of (a). [Figure 3] shows a central longitudinal sectional view of another embodiment of the valve for a semiconductor manufacturing apparatus of the present invention. [Figure 4](a) is an enlarged cross-sectional view of the main part of Figure 3. (b) is an enlarged cross-sectional view of the main part showing the closed valve state of (a). Implementation

[0026] The following is a detailed description of an embodiment of the valve for a semiconductor manufacturing apparatus according to the present invention, based on the accompanying drawings. Figure 1 illustrates an embodiment of the valve for a semiconductor manufacturing apparatus of the present invention (hereinafter referred to as valve body 1). In the figure, valve body 1 is an automatic valve comprising: a main body 2, a base 3, a support member 4, a diaphragm block 5, a diaphragm 6, and a valve seat sheet 7. Valve body 1 is a valve for a semiconductor manufacturing apparatus formed by a diaphragm valve that opens and closes by contact separation between the diaphragm 6 and the valve seat sheet 7. The valve body 1 is provided with an opening and closing mechanism 8 for closing the valve by pressing the diaphragm 6, and a load-distributing member 10 is provided inside the opening and closing mechanism 8. The valve body 1 has an actuator 11 on its upper part, which is configured to automatically operate for opening and closing control.

[0027] In Figure 1, a primary flow path 12 and a secondary flow path 13 are formed on the left and right sides of the main body 2 of the valve body 1, respectively. A valve chamber 14 is provided between the primary flow path 12 and the secondary flow path 13. Inside the valve chamber 14, an opening 16 is formed on the annular mounting groove 15 and the upper side of the valve chamber 14, respectively. A female thread 17 is formed on the upper inner circumference of the opening 16. A circular hole-shaped fitting part 18 is formed between the female thread 17 and the valve chamber 14 on the lower side.

[0028] The valve seat sheet 7 is formed into a ring shape using a fluorinated resin material such as PCTFE (polyvinyl chloride trifluoroethylene) or PFA (a copolymer of tetrafluoroethylene and perfluoroalkoxyethylene), and is installed in the mounting groove 15 such that the sealing surface 7a on the front end can seal against the diaphragm 6. The valve seat sheet 7 is configured to face the diaphragm 6 in order to control the flow of fluid.

[0029] The diaphragm 6 is constructed by overlapping multiple thin sheet-like metal pieces. In its natural state, it is shaped like a circular plate with a gently convex curved surface facing one side (upwards) and having the elasticity to self-restore its shape. The diaphragm 6 is mounted on the fitting part 18 on the upper side of the valve seat sheet 7.

[0030] At the upper part of the diaphragm 6, a cylindrical cap portion 19 is fitted into the diaphragm 6 by a fitting portion 18. A generally cylindrical diaphragm block 5 is formed in the center of the cap portion 19 and is inserted in a state that can slide in the vertical direction. The diaphragm block 5 is configured to be able to move in the vertical direction relative to the cap portion 19 by means of the support member 4, and the diaphragm block 5 is used to press the diaphragm 6 toward the valve seat sheet 7.

[0031] The base 3 has a through hole 20 in the center and a male thread 21 that can engage with the female thread 17 on its lower outer periphery. A circular groove 22 is formed on the upper part of the base 3, and a bottom surface 23 is provided in the groove 22. On the other hand, a male thread portion 24 is formed on the upper outer periphery of the base 3. With the diaphragm 6, the round cap portion 19 and the diaphragm block 5 installed between the base 3 and the main body 2, the base 3 is installed on the upper part of the round cap portion 19 by engaging the male thread 21 with the female thread 17. After such engagement, the round cap portion 19 is pressed down by the bottom surface of the base 3, and the round cap portion 19 is used to position and fix the diaphragm 6 in a predetermined position between it and the main body 2.

[0032] The support member 4 is configured to have the following shapes: a shaft portion 4a formed on the lower side, an enlarged section portion 4b that is slightly larger in diameter than the shaft portion 4a, and an enlarged annular portion 4c that is further enlarged in diameter than the enlarged section portion 4b. The shaft portion 4a is inserted into the through hole 20 with the O-ring 25 sealed, thereby allowing the support member 4 to move up and down relative to the base 3. The lower end of the support member 4 abuts against the upper end face of the diaphragm block 5, and the valve seat sheet 7 is pressed by the diaphragm 6 through the diaphragm block 5 by the up and down movement of the support member 4. Between the enlarged annular portion 4c and the annular mounting groove 26 formed on the outer diameter side of the through hole 20, the coil spring 27 is installed in an extended state, by means of the spring 27 causing the support member 4 to constantly push upwards relative to the base 3.

[0033] The actuator 11 includes: a generally cylindrical cover 30, an annular housing 31, a piston 32, and a coiled spring 33. A guide hole 34 is formed in the lower center of the cover 30, and an intake / exhaust port 35 is formed in the upper part of the guide hole 34. An annular mounting groove 36 is formed on the outer diameter side of the guide hole 34, and the spring 33 is mounted in the mounting groove 36.

[0034] A reduced-diameter shaft 32a formed in the piston 32 is inserted into the guide hole 34, and a spring 33 is inserted between the piston 32 and the mounting groove 36. The inner circumference of the outer casing 31 is integrated with the lower outer circumference of the cover 30 by screwing, and a cylinder chamber 37 for supplying compressed air is provided between the piston 32 and the outer casing 31. A female thread portion 38 is formed on the lower inner circumference of the outer casing 31.

[0035] The actuator 11 is integrally fixed to the base 3 by the engagement of the female thread 38 and the male thread 24. After the actuator 11 is assembled, the piston 32 is mounted with its lower end face abutting against the upper side of the expanded diameter annular portion 4c, allowing it to reciprocate in the vertical direction. The piston 32 is configured to descend relative to the housing 31 by the elastic force of the spring 33. Furthermore, compressed air is supplied to the cylinder chamber 37 from the intake and exhaust ports 35 through the flow path hole 32b formed in the piston 32, and the piston 32 is configured to rise against the elastic force of the spring 33 by the compressed air.

[0036] With this structure, when the supply of compressed air in Figure 2(b) stops and the piston 32 descends, the piston 32 presses the support member 4 downwards, and the diaphragm block 5 presses the diaphragm 6. When the diaphragm 6 is seated on the valve seat sheet 7, it becomes a closed valve sealing state. On the other hand, when the compressed air in Figure 2(a) is supplied and the piston 32 rises, the pressure of the support member 4 and the diaphragm block 5 on the diaphragm 6 is released. By the aforementioned self-restoring force, the diaphragm 6 returns to its convex curved surface shape with the center as the apex, thereby separating from the valve seat sheet 7 and becoming an open valve.

[0037] The aforementioned opening and closing mechanism 8 is an automatic valve using the actuator of this embodiment. It is composed of the piston 32 and spring 33 of the actuator 11. The piston 32 and spring 33 generate a thrust to close or open the diaphragm valve.

[0038] The thrust generated by the opening and closing mechanism 8 is expressed as thrust [N] = pressure area [mm 2] × pressure [MPa]. Based on this relationship, the thrust is transmitted from the piston 32 to the support member 4. In the aforementioned relationship, the pressure area is the total area on which the thrust is applied, and the pressure is the force applied to each unit area of ​​the pressure area.

[0039] The load dispersion member 10 disposed inside the opening and closing mechanism 8 is formed into a ring-shaped load dispersion sheet, for example, by an elastic material such as a fluorinated resin such as PCTFE or PFA, nylon, or ABS. In this embodiment, the load dispersion sheet 10 is formed by a fluorinated resin.

[0040] The load-dispersing sheet 10 is installed between the expansion section 4b of the support member 4 and the bottom part 23 of the base 3 at the connection point of the opening and closing mechanism 8 (piston 32, spring 33). The load from the piston 32 (support member 4) can be dispersed by the load-dispersing sheet 10. In this case, the diaphragm 6 is sandwiched between the main body 2 and the round cap 19 to seal the fluid, thereby making the load-dispersing sheet 10 a position that does not come into contact with the fluid in the flow path (primary side flow path 12, secondary side flow path 13, valve chamber 14) of the valve body 1.

[0041] The load-distributing sheet 10 is arranged in parallel with the valve seat sheet 7, and in the open valve state, the load-distributing sheet 10 and the aforementioned connecting portion of the opening and closing mechanism 8 (the expanded diameter section 4b of the support member and the bottom part 23 of the base) are configured with a predetermined gap X1 as shown in FIG. 2(a). In this embodiment, the load-distributing sheet 10 and the valve seat sheet 7 are installed parallel to each other. On the other hand, on the diaphragm 6 mounting side, when the valve is open, the bottom surface of the diaphragm 6 and the sealing surface 7a of the valve seat sheet 7 are set with the stroke of the diaphragm 6, i.e., a predetermined gap X2.

[0042] The gaps X1 and X2 in the open valve state are related as X1 = X2. When the valve is closed, the diaphragm 6 abuts (sits) against the valve seat sheet 7, and the abutting side of the expanded diameter section 4b contacts the load-distributing sheet 10. The thrust from the piston 32 and spring 33 of the actuator 11 is also applied to the load-distributing sheet 10. Thus, the valve body 1 becomes a dual structure that maintains the thrust generated by the opening and closing mechanism 8 while distributing the sealing load necessary for closing the valve to the valve seat sheet 7 and the load distributing member 10.

[0043] When the aforementioned load-distributing sheet 10 and valve seat sheet 7 are configured, it is necessary to ensure that the load transmitted from the piston 32 is distributed (distributed) well in a balanced manner between the load-distributing sheet 10 and the valve seat sheet 7. Therefore, for either sheet 7 or 10, it is necessary to consider the range of elastic deformation and the range of mechanical tolerances after configuration when setting the dimensions.

[0044] For example, when the valve is closed, if the expanded section 4b contacts the load-distributing plate 10 before the diaphragm 6 is seated on the valve seat plate 7, the valve will not be sealed, and fluid leakage will not occur. On the other hand, if the diaphragm 6 is seated on the valve seat plate 7 before the expanded section 4b contacts the load-distributing plate 10, all the load from the piston 32 on the diaphragm 6 side will be concentrated on the valve seat plate 7. In either case, the load cannot be distributed by the dual structure of the valve seat plate 7 and the load-distributing plate 10.

[0045] In addition, it is difficult to make the dimensional error of mechanical processing deviation zero. Therefore, it is necessary to design it so that, after taking into account processing tolerances, the valve seat sheet 7 is arranged in a balanced and effective manner in such a way that the expanded diameter section 4b contacts the load distribution sheet 10 within the allowable elastic deformation range.

[0046] When setting these thin plates 7 and 10, firstly, after setting the area ratio of each thin plate 7 and 10 under load, the thickness of the valve seat thin plate 7 (height of the sealing surface 7a) can be set by considering the hardness or the elastically deformable size ratio in the thickness direction of the load-dispersing thin plate 10. Furthermore, the thickness of the load-dispersing thin plate 10 can be designed to be sufficiently large, if necessary. The reason for this is that by setting the thickness of the valve seat thin plate 7 to be larger, the range of expansion and contraction for safe elastic deformation can be increased. Similarly, by increasing the thickness of the load-dispersing thin plate 10, the range of elastic deformation can also be increased.

[0047] As described above, increasing the thickness of the load-dispersing sheet 10 or the valve seat sheet 7 can prevent the load-dispersing sheet 10 from contacting the support member 4 first, causing the load to concentrate at that location and resulting in incomplete valve closure and leakage, or prevent the diaphragm 6 from contacting the valve seat sheet 7 first, causing the load to concentrate at the valve seat sheet 7 and resulting in damage.

[0048] As a specific example, when the sheets 7 and 10 are set with PCTFE, the maximum elastic deformation within the load range not exceeding the pressure limit of the PCTFE is 10%. In this case, the cumulative error in the height direction of the valve seat sheet 7 and the load-distributing sheet 10 caused by the combined effect of the processing tolerance and assembly error of the diaphragm 6 or the support member 4 is ±0.1mm (range value 0.2mm). Therefore, the thickness of the valve seat sheet 7 can be set to be greater than or equal to the range of this error, 0.2[mm] / 10[%] = 2.0mm.

[0049] If, for some reason, the thickness of the valve seat sheet 7 cannot be adequately ensured, the thickness of the load-distributing sheet 10 can be set in the same manner as described above, replacing the valve seat sheet 7. However, when the load-distributing sheet 10 is thickened, its range of elastic deformation increases. Therefore, when the valve seat sheet 7 softens, it is necessary to consider that the function of maintaining the thickness may be slightly reduced in terms of the sinking of the valve seat sheet 7.

[0050] For example, the load borne by the load-distributing sheet 10 is fixed regardless of its thickness. If we assume that it deforms by 10% due to the load, the 10% deformation amount when its thickness is 1.0 mm is 0.1 mm. And, the 10% deformation amount when its thickness is 2.0 mm is 0.2 mm. If we compare these, the difference in deformation amount is 0.1 mm, which will widen the difference in the range of elastic deformation. Therefore, when the valve seat sheet 7 softens, the valve seat sheet 7 may sink too much.

[0051] Furthermore, when selecting the material for the load-dispersing sheet 10, it is necessary to consider its material properties such as elasticity or hardness. In addition, it is also desirable to consider the characteristics of the components such as the support members 4 and the substrate 3 around the placement position of the load-dispersing sheet 10, their compatibility with the lubricant applied inside, and the external environment such as the operating temperature of the valve body 1.

[0052] Furthermore, the load-distributing member 10 can be made of various materials other than resin, and in various shapes other than annular sheets. Although not shown, a disc spring or leaf spring with spring characteristics can be used as the load-distributing member, and such a disc spring or leaf spring can be installed between the expanded diameter section and the bottom section (not shown).

[0053] Furthermore, the load-distributing member 10 can be a dual structure that maintains the thrust while distributing the sealing load necessary for valve closure between itself and the valve seat sheet 7. It can be fixed to the bottom surface 23 side of the base 3 or the expanded diameter section 4b side of the support member 4. Moreover, the load-distributing sheet 10 can be installed at any location within the valve body 1, not limited to between the support member 4 and the base 3.

[0054] When the load-dispersing plate 10 is set, as long as the size difference between the gap X1 and the gap X2 can be set, the necessary sealing load when closing the valve can be dispersed by the valve seat plate 7 and the load-dispersing plate 10 in a dual structure, for example, the elastic force or material of the load-dispersing plate 10, or the shape or material of the diaphragm 6, can be appropriately set, and the gap X1 and the gap X2 can be appropriately set accordingly.

[0055] In this embodiment, although an example of using a diaphragm valve as a valve for a semiconductor manufacturing apparatus is described, it is not limited to diaphragm valves. For example, it can also be applied to various valves such as needle or ball valves not shown in the figure.

[0056] Next, the operation and function of the valve for the semiconductor manufacturing apparatus of the present invention as described above will be explained. In Figures 1 and 2, the valve body 1, together with the actuator 11, is linked to the opening and closing mechanism 8, the support member 4, the diaphragm block 5, the coil spring 27, and other parts, transmitting the generated thrust to the diaphragm 6 or the valve seat sheet 7, so that the sealing parts of these parts are in close contact with each other to form a closed or open valve state, thereby controlling the flow of fluid.

[0057] In Figures 1 and 2(a), if compressed air is supplied from the intake and exhaust ports 35 to the cylinder chamber 37 through the flow path hole 32b, the piston 32 will rise against the elastic thrust of the spring 33 by the compressed air. As a result, the pressure of the support member 4 and the diaphragm block 6 on the diaphragm 6 is released, and the diaphragm 6 separates from the valve seat sheet 7 and becomes an open valve.

[0058] In this case, the connection points of the opening and closing mechanism 8 (piston 32, spring 33), namely the expanded diameter section 4b of the support member 4 and the bottom part 23 of the base 3, are configured with the load-distributing sheet 10 with a predetermined gap X1, and no sealing load from the piston 32 is applied. Therefore, the thrust of the opening and closing mechanism 8 will not act on either the load-distributing sheet 10 or the valve seat sheet 7.

[0059] On the valve seat sheet 7 side, a gap X2 with the same height as the gap X1 is provided between the valve seat sheet 7 and the diaphragm 6. The gap X2 is used to reliably ensure the flow path, so that the fluid can flow smoothly from the primary flow path 12 to the secondary flow path 13.

[0060] On the other hand, in Figure 2(b), when the supply of compressed air is stopped, the force that causes the piston 32 to rise stops, and the force that causes the piston 32 to fall by the elastic thrust of the spring 33 begins to operate. The force of the piston 32 presses the support member 4 and the diaphragm block 5 downwards, and the diaphragm block 5 presses down on the diaphragm 6. As a result, the diaphragm 6 sits on the valve seat sheet 7, achieving a closed, sealed state.

[0061] As mentioned above, while maintaining the thrust generated by the opening and closing mechanism 8, the sealing load necessary for closing the valve is distributed to the valve seat plate 7 and the load distribution plate 10, which is a different component from the valve seat plate 7 and is arranged in parallel inside the opening and closing mechanism 8. This creates a dual structure that distributes the sealing load. Therefore, it is not necessary to change the magnitude of the sealing load thrust of the piston 32 necessary for closing the valve seal, and the pressure caused by the thrust can be distributed to the valve seat plate 7 and the load distribution plate 10.

[0062] At this time, the valve seat plate 7 and the load-distributing plate 10 are arranged in a parallel state. Therefore, by using the aforementioned relationship of thrust = pressure area × pressure, the thrust caused by the piston 32 can be expressed as (pressure area of ​​valve seat plate 7 × pressure applied to valve seat plate 7) + (pressure area of ​​load-distributing plate 10 × pressure applied to load-distributing plate 10).

[0063] This reduces the surface pressure (load per unit area) on the valve seat plate 7, lessening the damage to the valve seat plate 7, and eliminates the need to reduce the thrust generated by the opening and closing mechanism 8, ensuring sufficient sealing capability even for higher fluid pressures. In this case, without reducing the sealing force caused by the piston 32, the predetermined thrust necessary to prevent leakage can be applied to the valve seat plate 7 and the load-dispersing plate 10 with reduced pressure (surface pressure), reducing the burden on the valve seat plate 7 compared to the case without the load-dispersing plate 10. Therefore, by selecting a fluorinated resin with excellent chemical resistance for the valve seat plate 7 or the load-dispersing plate 10, the sealing load can be mitigated without adding extra load (thrust) from the actuator 11 side, preventing damage to the valve seat plate 7 and the load-dispersing plate 10 or malfunction of the valve body 1.

[0064] It is not necessary to increase the size of the valve seat plate 7 to suppress the pressure on it, thereby increasing the pressure-bearing area and preventing the valve body 1 from becoming too large, thus ensuring compactness. There is also no need to limit the pressure of the fluid flowing within the valve body 1; simply reducing the surface pressure applied to the valve seat plate 7 ensures the required sealing performance and flow characteristics of the valve body 1, and allows for the flow of high-pressure fluids. Therefore, even when the valve body 1 is made more compact due to aggregation, the dual structure of the short-diameter valve seat plate 7 distributes the sealing load, preventing excessive surface pressure and improving durability.

[0065] By positioning the load-dispersing sheet 10 on the side of the concave groove 22 that does not come into contact with the fluid inside the valve body 1, deterioration or damage to the load-dispersing sheet 10 can be prevented. Therefore, even if the valve seat sheet 7 softens due to corrosive fluid, the load-dispersing sheet 10 will still bear the load originally borne by the valve seat sheet 7. In this way, a highly durable valve body 1 can be provided, which can prevent the valve seat sheet 7 from being continuously damaged and losing its sealing performance, and can continue to operate normally even if the valve seat sheet 7 softens.

[0066] The specifications of the spring load and driving air pressure used to press the piston 32 are calculated in advance. Even when the valve is closed and pressure is applied in the direction of opening due to the fluid, the thrust generated from the piston 32 can prevent the valve from opening naturally. Furthermore, the same function is also present in the manual valve with a handle described later. In this case, the thrust generated from the handle is used as a sealing load. The thread diameter or thread pitch of the handle is calculated in advance to prevent the valve from opening naturally.

[0067] In the case of valve body 1, especially for high-pressure valves, a large sealing load is required to prevent operation from being hindered by high-pressure fluid. Therefore, it is necessary to set the thrust of piston 32 to be large. In this case, for example, if PCTFE is used as the material of valve seat sheet 7, the tensile strength of PCTFE is known to be approximately 41 MPa. Taking this value as the limit, if valve seat sheet 7 is provided alone without load-distributing sheet 10, there is a possibility that valve seat sheet 7 will plastically deform and collapse or be damaged when a surface pressure exceeding 41 MPa is applied to valve seat sheet 7. When load-distributing sheet 10 is provided, the surface pressure is distributed to load-distributing sheet 10, which can prevent the surface pressure exceeding 41 MPa from being applied to valve seat sheet 7.

[0068] Figures 3 and 4 illustrate other embodiments of the valve for the semiconductor manufacturing apparatus of the present invention. Furthermore, in these embodiments, parts identical to those in the above embodiments are indicated by the same symbols, and their descriptions are omitted.

[0069] The valve body 40 of this embodiment is a manual valve, which is a diaphragm valve having a main body 41, a base 42, a branch 43, a diaphragm block 44, a diaphragm 45, a valve seat sheet 46, a load-distributing sheet (load-distributing component) 47, and a handle 48.

[0070] The valve body 40 is provided with an opening and closing mechanism 43, which is composed of a branch provided on the handle 48. It is configured such that the valve can be closed by pressing the diaphragm 45 through the branch 43. In a predetermined position inside the main body 41, a valve seat sheet 46 is installed in the same manner as in the previous embodiment. With the diaphragm 45 inserted into the valve seat sheet 46, the diaphragm block 44 is installed on the main body 41 through the round cap portion 49.

[0071] The base 42 is cylindrical, with a through hole 50 in the center and a female thread 52 at the bottom that engages with the male thread 51 formed on the upper part of the main body 41. The base 42 is integrated with the main body 41 by the engagement of the male thread 51 and the female thread 52. At this time, the pressing surface 53 provided on the bottom side of the inner circumference of the base 42 presses the top surface 49a of the round cap portion, thereby pressing the diaphragm 45 and fixing the diaphragm 45 between the round cap portion 49 and the main body 41. A female thread portion 54 is formed on the upper side of the through hole 50.

[0072] A male thread 55 is formed on the outer periphery of the branch 43, which engages with the female thread 54. The engagement of the male thread 55 with the female thread 54 allows the branch 43 to be mounted in a height-adjustable position relative to the base 42. At the upper end of the branch 43, a handle 48 is fixed by a stop screw 56. The branch 43 moves up and down relative to the base 42 by rotating the handle 48, which rotates integrally with the handle. A reduced-diameter protrusion 43a is formed on the bottom surface of the branch 43, and an expanded-diameter section 43b is formed on the upper part of the protrusion 43a. When the branch 43 is moved up and down, the protrusion 43a presses or releases pressure on the diaphragm block 44 and the diaphragm 45, thereby opening and closing the flow path.

[0073] The load-dispersing sheet 47 is installed between the outer periphery of the branch protrusion 43a and the upper surface 49a of the round cap portion. Thus, similar to the aforementioned embodiment, the load-dispersing sheet 47 is arranged side-by-side with the valve seat sheet 46.

[0074] In Figure 4(a), when the opening and closing mechanism, i.e. the branch 43, is in the rising open valve state, the connecting part of the opening and closing mechanism 43, i.e. the expanded diameter section 43b, and the load distribution sheet 47 are configured with a predetermined gap Y1. At this time, on the diaphragm 45 mounting side, in the open valve state, the bottom surface of the diaphragm 45 and the sealing surface 46a of the valve seat sheet 46 are open with the stroke of the diaphragm 45, i.e., the gap Y2. In the open valve state, these gaps Y1 and Y2 are in a relationship where gap Y1 = gap Y2.

[0075] On the other hand, Figure 4(b) shows a dual structure where rotating the handle 48 and lowering the branch 43 generates a thrust. This thrust is maintained while the sealing load necessary for valve closure is distributed between the valve seat plate 46 and the load-distributing plate 47. That is, the load-distributing plate 47 is positioned where the thrust from the branch 43 on the handle 48 is applied when the diaphragm 45 contacts the valve seat plate 46.

[0076] As described above, the opening and closing mechanism 43 is applied to a manual valve, using the valve seat plate 46 and the load-distributing plate 47 to distribute the sealing load, thereby achieving the same function as the aforementioned embodiment. In particular, it can prevent damage to the valve seat plate 46 caused by over-tightening the handle 48. Furthermore, even if designed with a large thrust, the impact on the valve seat plate 46 can be minimized, and sufficient sealing performance can be maintained. Therefore, it can prevent insufficient sliding resistance between the bottom surface of the protrusion 43a and the diaphragm block 44, and between the male thread portion 55 and the female thread portion 54, which is prone to occur when suppressing the sealing load, and it can also prevent poor sealing caused by the reverse rotation of the handle 48 due to insufficient sliding resistance. [Example]

[0077] Next, an embodiment of setting the valve seat sheet and load distribution sheet of the valve for a semiconductor manufacturing apparatus will be described. In the valve body 1 of the embodiment of the structure shown in Figure 1, in order to compare the case where the valve seat plate 7 alone bears the sealing load (thrust) without the load distribution plate 10 and the case where both the load distribution plate 10 and the valve seat plate 7 bear the thrust in the aforementioned embodiment, the magnitude of the force applied to the plates 7 and 10 in each case is determined.

[0078] As a condition for high-pressure gas valves, a valve body 1 is provided that can operate at pressures up to 20.6 MPa. In this case, a design margin of 10% is set, the effective area of ​​the diaphragm 6 is assumed to be 88.4 mm², and the reaction force P generated by the fluid pressure on the diaphragm 6 is set as reaction force P = 88.4 × 20.6 × 1.1 ≒ 2003 [N]. In order to reliably perform the valve closing action by pressing the diaphragm 6 which bears the reaction force P, the opening and closing mechanism 8 and other parts, including the spring load, are designed such that the thrust F of the spring 33 exceeds the reaction force P. Furthermore, the sealing load generated by the thrust F when closing the valve is constantly applied even when the fluid supply stops and there is no internal pressure.

[0079] The sealing surface 7a of the valve seat sheet 7 used in the valve body 1 has an outer diameter of φ6.6mm and an inner diameter of φ3.6mm, and its effective area is (6.6 / 2) 2×π-(3.6 / 2) 2×π≒24.0mm 2.

[0080] First, when the valve body 1 does not have a load-distributing plate 10 and only the valve seat plate 7 is used, the surface pressure of the reaction force P is 2003÷24.0=83.5[MPa]. As described above, without the load-distributing sheet 10, the surface pressure (83.5 MPa) would significantly exceed the yield strength (tensile strength) of the aforementioned PCTFE, which is 41 MPa. Therefore, in the case of repeated use, there is a very high probability that the valve seat sheet 7 will be unable to withstand the surface pressure and undergo plastic deformation, resulting in damage or breakage.

[0081] On the other hand, when the valve seat sheet 7 and the load-dispersing sheet 10 are arranged side by side, in addition to the valve seat sheet 7 with a sealing surface size (effective area) of 24.0 mm², the load-dispersing sheet 10 with an effective area (the respective opposing areas of the expanded diameter section and the bottom section) of 26.0 mm² is also used. Therefore, the total effective area (total area) of the valve seat sheet 7 and the load-dispersing sheet 10 is 50.0 mm². Therefore, the reaction force P (2003 [N]) on the surface pressure of the total area of ​​50 mm 2 will be 2003 ÷ 50.0 ≒ 40 [MPa].

[0082] With the load-distributing sheet 10 set as described above, for a typical PCTFE yield strength of 41 MPa, the surface pressure borne by the valve seat sheet 7 will converge to a value within the material's pressure resistance limit. Therefore, damage to the valve seat sheet 7 can be prevented.

[0083] Furthermore, even if corrosive gases or other substances penetrate the valve seat sheet 7 and soften it, damage to the valve seat sheet 7 can be reduced. For example, when the yield strength of the valve seat sheet 7 is reduced to 20.5 MPa (50% of the normal value of 41 MPa) due to chemicals, etc., without the load-dispersing sheet 10, the surface pressure of 83.5 MPa will be applied to the valve seat sheet 7. Therefore, the ratio is 83.5 [MPa] ÷ 20.5 [MPa] = 4.1. It is believed that the 4.1 times surface pressure will make it prone to damage.

[0084] In contrast, when both the valve seat plate 7 and the load-dispersing plate 10 are used, the surface pressure applied to their combined area is 40 MPa. Therefore, the ratio of this surface pressure to the yield strength of the valve seat plate 7 is 40 [MPa] ÷ 20.5 [MPa] = 1.95. As described above, by suppressing the surface pressure to 1.95 times, damage can be significantly reduced compared to the case where the load-dispersing plate 10 is not provided.

[0085] Furthermore, the aforementioned load-dispersing sheet 10 is designed considering the relationship between the thrust or yield strength applied to the valve seat sheet 7. Specifically, when the yield strength of the valve seat sheet 7 decreases to 20.5 MPa, the ultimate thrust (thrust without plastic deformation) of the valve seat sheet 7 alone is calculated as 24.0 [mm 2] × 20.5 [MPa] = 492 [N], which is the area of ​​the sealing surface (effective area) × the softened pressure resistance. Since the total thrust generated by the piston is 2003 [N], the thrust that the load-dispersing sheet 10 should bear alone is 2003 [N] - 492 [N] = 1511 [N].

[0086] For this thrust, the surface pressure borne by the load-dispersing sheet 10 is 1511 [N] ÷ 26.0 [mm 2] = 58.1 [MPa]. Therefore, to make the pressure resistance of the load-dispersing sheet 10 greater than 58.1 MPa, in this example, MC nylon (registered trademark) (yield strength 96 MPa) is used as the material. In this case, even if the valve seat sheet 7 softens and flattens, the load-dispersing sheet 10 can still bear a higher load independently, preventing the valve seat sheet 7 from flattening beyond its elastic deformation range.

[0087] As described above, by setting the load-distributing plate 10 to properly distribute the thrust, it is possible to manufacture the valve body 1 while maintaining a compact design without imposing design limitations on its performance or product size. Furthermore, it has been confirmed that the tamping strength of the valve seat plate 7 is not lost and its functionality is not compromised.

[0088] While the embodiments of the present invention have been described in detail above, the present invention is not limited to the aforementioned embodiments. Various modifications are possible without departing from the spirit of the invention as described in the claims.

[0089] 1,40: Valve body 4: Supporting components 6: Diaphragm 7: Valve seat thin plate 8: Opening and closing mechanism 10: Load-distributing sheet (load-distributing component) 11: Actuator 32: Piston 33: Spring 43: Branches and Stems 48: Grip X1, X2, Y1, Y2: Gap

Claims

1. A valve for a semiconductor manufacturing apparatus, which opens and closes by contact separation between a diaphragm and a valve seat sheet disposed on a valve body, characterized in that an opening and closing mechanism for pressing the diaphragm to close the valve is provided in the valve body, and a load-distributing member is disposed inside the opening and closing mechanism. The load-distributing member, in a state parallel to the valve seat sheet and in the open state, is configured such that the connection portion of the opening and closing mechanism and the load-distributing member have a predetermined gap, forming a dual structure that maintains the thrust generated by the opening and closing mechanism while distributing the sealing load required for closing the valve between the valve seat sheet and the load-distributing member. The load per unit area is set to be within the material's pressure resistance limit and to suppress the increase of the pressure-bearing area. The aforementioned valve seat sheet and the aforementioned load-distributing member are set to have an area ratio when bearing the load. The load transmitted is balanced and well distributed within the range of elastic deformation and mechanical tolerance. The thickness of the aforementioned valve seat sheet or the aforementioned load-distributing member is set according to the hardness of the aforementioned load-distributing member or the ratio of the size that can be elastically deformed relative to the thickness direction. It is set that when the valve is closed, the aforementioned diaphragm contacts the aforementioned valve seat sheet, and the thrust from the aforementioned opening and closing mechanism is applied to the aforementioned load-distributing member.

2. The valve for a semiconductor manufacturing apparatus as described in claim 1, wherein, The aforementioned load-distributing component is located in a part of the flow path that does not come into contact with the fluid in the aforementioned valve body.

3. The valve for a semiconductor manufacturing apparatus as described in claim 1 or 2, wherein, The aforementioned load-dispersing component is a ring-shaped load-dispersing sheet made of resin or a disc spring with spring properties.

4. The valve for a semiconductor manufacturing apparatus as described in claim 1 or 2, wherein, In the case of an automatic valve, the aforementioned opening and closing mechanism is constructed using a piston or spring of an actuator; in the case of a manual valve, it is located on a support in the handle.

5. The valve for a semiconductor manufacturing apparatus as described in claim 3, wherein, In the case of an automatic valve, the aforementioned opening and closing mechanism is constructed using a piston or spring of an actuator; in the case of a manual valve, it is located on a support in the handle.

6. The valve for a semiconductor manufacturing apparatus as described in claim 4, wherein, The aforementioned load-distributing component is positioned such that, while the aforementioned diaphragm is in contact with the aforementioned valve seat sheet, it is subjected to a thrust from the piston or spring of the aforementioned actuator, or from the thrust of the handle support.

7. The valve for a semiconductor manufacturing apparatus as described in claim 5, wherein, The aforementioned load-distributing component is positioned such that, while the aforementioned diaphragm is in contact with the aforementioned valve seat sheet, it is subjected to a thrust from the piston or spring of the aforementioned actuator, or from the thrust of the handle support.

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