High-tight valve

Abstract

To provide a highly airtight valve which is improved in airtightness, and a substrate housing container comprising the same.SOLUTION: An air intake valve 20, which is a highly airtight valve, comprises: a housing plug 21; a check valve 25 arranged inside the housing plug; a flat packing 23 which seals the periphery of the air intake and exhaust port in an airtight manner; an elastic ring cushion 24; and a ring cover 22 which is mounted to the housing plug and covers the flat packing and the ring cushion. The ring cover engages with the flange portion of the housing plug and has an opening through which the air intake and exhaust port of the housing plug is exposed, the flat packing is slidably held on the outer periphery of the main body of the housing plug and has a planar airtight surface surrounding the periphery of the air intake and exhaust port and protrudes from the opening, and the ring cushion is arranged on the outer periphery of the main body of the housing plug, between the flat packing and the flange portion of the housing plug.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a highly airtight valve used as an air supply valve or an exhaust valve or the like for purging the air inside a container body such as a substrate storage container for storing semiconductor wafers and replacing it with an inert gas.

Background Art

[0002] Conventionally, a substrate storage container for storing a plurality of semiconductor wafers arranged vertically is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The substrate storage container of Patent Document 1 can store a plurality of semiconductor wafers arranged vertically. In the manufacturing process of semiconductor wafers, it is placed on a lid opening / closing device, the lid is opened, and the semiconductor wafers are taken out or stored by a robot arm or the like. And, an air supply valve and an exhaust valve are provided on the bottom plate of the container body of the substrate storage container. By being arranged at a predetermined position of the lid opening / closing device, an inert gas is continuously supplied into the container through a purge nozzle of a purge device to purge the air, thereby preventing surface oxidation, contamination of the semiconductor wafers, and corrosion of the wiring.

[0005] As described above, the substrate storage container is positioned in a predetermined location such as the lid opening / closing device to connect the purge nozzle of the purge device with the supply and exhaust valves of the substrate storage container. However, a gap may form in the connection between the purge nozzle of the purge device and the supply and exhaust valves of the substrate storage container, potentially causing inert gases such as nitrogen gas to leak out and preventing the supply of inert gas at sufficient pressure into the substrate storage container.

[0006] The present invention aims to improve the airtightness of supply and exhaust valves used in substrate storage containers and the like that can store multiple semiconductor wafers arranged vertically. [Means for solving the problem]

[0007] One embodiment comprises a housing plug, a check valve disposed inside the housing plug, a flat packing that airtightly seals the area around the intake and exhaust ports, an elastic ring cushion, and a ring cover attached to the housing plug and covering the flat packing and ring cushion. The housing plug has a main body having a flow path leading to the intake and exhaust ports and a check valve disposed within the flow path, and a flange portion extending from the main body outward. The ring cover engages with the flange portion of the housing plug and has an opening that exposes the intake and exhaust ports of the housing plug. The flat packing is slidably held on the outer circumference of the main body of the housing plug, has a planar airtight surface surrounding the intake and exhaust ports and protrudes from the opening. The ring cushion is a highly airtight valve disposed on the outer circumference of the main body of the housing plug, between the flat packing and the flange portion of the housing plug. [Effects of the Invention]

[0008] According to this embodiment, it is possible to improve the airtightness of supply and exhaust valves used in substrate storage containers and the like that can store multiple semiconductor wafers arranged vertically. [Brief explanation of the drawing]

[0009] [Figure 1] This is an example of an overall perspective view of the container body of the substrate storage container of the embodiment, where (a) is a view from the opening side and (b) is a view from below. [Figure 2] This is an example of an overall perspective view of the high-airtight valve (air supply valve) of the embodiment, where (a) is a view from the mounting side and (b) is a view from the air supply port side. [Figure 3] This is an example of a diagram of an airtight valve (air supply valve) according to an embodiment, where (a) is a side view and (b) is a longitudinal cross-sectional view. [Figure 4] This is an example of an exploded perspective view of a highly airtight valve (air supply valve) according to the embodiment. [Figure 5] This is an example of an exploded perspective view of a highly airtight valve (exhaust valve) according to the embodiment. [Figure 6] This is an example of a diagram of a component (housing plug) constituting a high-airtight valve of the embodiment, where (a) is a plan view, (b) and (e) are side views, (c) is a rear view, (d) is a perspective view, and (f) is a longitudinal cross-sectional view. [Figure 7] This is an example of a diagram of a component (flat packing) constituting a high-airtight valve of the embodiment, where (a) is a plan view, (b) is a side view, (c) is a longitudinal section of (a) AA, (d) is a perspective view, and (e) is a perspective view from the opposite side. [Figure 8] This is an example of a diagram of a component (ring cushion) constituting a high-airtight valve of the embodiment, where (a) is a plan view and (b) is a longitudinal cross-sectional view. [Figure 9] This is an example of a diagram of a component (ring cover) constituting a high-airtight valve of the embodiment, where (a) is a rear view, (b) is a side view, (c) is a top view, (d) is a perspective view, (e) is a longitudinal section AA of (a), and (f) is a longitudinal section BB of (b). [Figure 10] These figures illustrate the usage state of the high-airtight valve of the embodiment; (a) is a schematic diagram showing the relationship between the high-airtight valve attached to the substrate housing container and the purge nozzle, and (b) is a schematic diagram of the vertical cross-section of the high-airtight valve in use. [Modes for carrying out the invention]

[0010] One embodiment of the highly airtight valve is, for example, attached to a substrate storage container B capable of storing multiple semiconductor wafers arranged vertically, and used as an air supply valve 20 for purging air by supplying an inert gas such as nitrogen gas into the storage container, or as an exhaust valve 30 for exhausting gas from inside the storage container.

[0011] As shown in Figure 1, the substrate storage container B comprises a container body 1 capable of aligning and storing multiple semiconductor wafers, and a lid (not shown) that closes the opening of the container body 1. The container body 1 has a pair of left and right support bodies 131 that are detachably attached to the inner surfaces of the left and right side walls 13, 13, respectively, for supporting semiconductor wafers in a substantially horizontal position. Note that in Figure 1(b), the pair of left and right support bodies 131 of the substrate storage container B are omitted.

[0012] The left and right pairs of support bodies 131 are formed by arranging plate-shaped support plates at a predetermined pitch in the vertical direction, and support grooves are formed between adjacent support plates in the vertical direction to support the lateral edges of the semiconductor wafer.

[0013] The container body 1 has multiple mounting holes 12a and 12b formed in the bottom plate 12 for supplying and exhausting air, and an air supply valve 20 or exhaust valve 30 can be connected to the supplying and exhausting mounting holes 12a and 12b as appropriate. In this embodiment, the substrate storage container B has two mounting holes 12a, 12a near the back of the bottom plate 12 and two mounting holes 12b, 12b near the opening. An air supply valve 20 is attached to the two mounting holes 12a near the back, and an air supply valve 20 and an exhaust valve 30 are attached to the mounting hole 12b near the opening. However, the valves attached to the mounting holes 12a near the back and the mounting holes 12b near the opening are not limited, and it is not necessary to attach some kind of valve to all of the mounting holes 12a, 12b. In addition, in FIG. 1, for the sake of explanation, an air supply valve 20 and an exhaust valve 30 are attached to the mounting holes 12a and 12b one by one.

[0014] The container body 1 is provided with a diffuser 151 having purge gas ejection holes at the rear position inside. The air supply valve 20 attached to the two mounting holes 12a near the back surface of the bottom plate 12 is continuous with the diffuser 151 arranged inside the container body 1.

[0015] In the process of manufacturing a semiconductor wafer, the substrate storage container B to which the air supply valve 20 and the exhaust valve 30 are attached is positioned and arranged at a predetermined position of a lid opening / closing device not shown in the figure. As shown in FIG. 10(a), the purge nozzle C1 for air supply of the purge device is continuous with the air supply valve 20 of the substrate storage container B, and the purge nozzle C2 for exhaust of the purge device is continuous with the exhaust valve 30 of the substrate storage container B.

[0016] For the substrate storage container B with the lid closed, for example, an inert gas is supplied from the purge nozzle C1 for air supply of the purge device to the air supply valve 20 attached to one mounting hole 12b near the opening. Thus, the inert gas is ejected into the inside of the container body 1 through the air supply valve 20, and the gas inside the container body 1 is exhausted to the purge nozzle C2 for exhaust through the exhaust valve 30 attached to the other mounting hole 12b near the opening. The air inside the container body 1 is purged and replaced with an inert gas.

[0017] Also, when the lid is opened and closed by the lid opening / closing device, the inert gas supplied through the air supply valve 20 attached to the mounting holes 12a and 12a near the back surface is ejected into the inside of the container body 1 from the ejection holes of the diffuser 151, preventing the entrainment of clean air or the like passing through the front surface of the opening, and maintaining the inside of the container body 1 in a state of being replaced with an inert gas.

[0018] If a gas leak occurs at the connection between the purge nozzle C1 of the purge device and the air supply valve 20 of the substrate storage container B, then inert gas at sufficient pressure will not be supplied into the substrate storage container B. For example, when the lid is opened, clean air passing in front of the opening may be drawn into the container body 1 and enter the container.

[0019] The air supply valve 20 and exhaust valve 30 used in the substrate storage container B of this embodiment are configured as highly airtight valves that can maintain high airtightness when positioned at a predetermined location on the lid opening / closing device and connected to the purge nozzle C1 (or purge nozzle C2) of the purge device, thereby suppressing gas leakage at the connection point. The configuration of the high-airtightness valve of this embodiment will be described in detail below, using the air supply valve 20 as an example and referring to the drawings. In the following description of the air supply valve 20, the side of the valve that is attached to the circuit board housing container B is referred to as the mounting side, and the side that is continuous with the purge nozzle is referred to as the air supply port side.

[0020] -High-airtight valve- As shown in Figures 2 to 4, the air supply valve 20 of this embodiment includes a housing plug 21 having a flow path continuous with the air intake port and having a check valve 25 positioned at a predetermined location in the flow path, a check valve 25 positioned inside the flow path of the housing plug 21, a flat packing 23 that airtightly seals the area around the air intake port of the air supply valve 20, a ring cushion 24, and a ring cover 22 attached to the housing plug 21 and covering the flat packing 23 and the ring cushion 24.

[0021] As shown in Figures 4 and 6, the housing plug 21 that constitutes the air supply valve 20 has a cylindrical shape that penetrates in the longitudinal direction and has a main body portion 211 in which a check valve 25 is arranged inside, and a plate-shaped flange portion 213 that extends from the outer circumference outward near the longitudinal center of the main body portion 211, with the opening on the air supply port side being the air supply port 20a of the air supply valve 20. The housing plug 21 that constitutes the air intake valve 20 is not limited in material, but for example, a resin material such as ABS resin can be used.

[0022] The housing plug 21 has threads 211d cut into the outer circumference of the mounting side of the main body 211, and a packing retaining portion 212 is provided on the air intake side of the main body 211 to slidably hold the flat packing 23.

[0023] As shown in Figure 6(e), the housing plug 21 is formed such that the outer dimensions w3 of the packing holding portion 212 are smaller than the outer dimensions w4 of the main body portion 211, and a retaining rib 212a is provided at the air intake side end of the packing holding portion 212, allowing the flat packing 23 to be movably held between the boundary portion of the packing holding portion 212 with the main body portion 211 having outer dimensions w4 on its outer circumference and the retaining rib 212a. Furthermore, the housing plug 21 may have the letters "IN" 211c inscribed on the side of the air intake port of the retaining rib 212a to indicate that the valve is an air intake valve.

[0024] As shown in Figure 6(f), the housing plug 21 is formed such that the inner diameter w1 of the packing retaining portion 212 in the through-flow channel is smaller than the inner diameter w2 of the main body portion 211, and a stepped portion 211a is formed on the inner circumference of the main body portion 211 at the boundary with the packing retaining portion 212 to position the check valve 25 which is arranged inside the flow channel of the main body portion 211.

[0025] The flange portion 213 of the housing plug 21 is formed as a disc-shaped portion extending outward from a position near the longitudinal center of the main body portion 211. The outer peripheral end of the disc-shaped flange portion 213 is provided with a plurality (six in this embodiment) of missing portions 213a that are absent on the inner peripheral side, and the flange portion 213 also has a pair of protrusions 213b, 213b that project outward from the outer peripheral end toward the mounting side.

[0026] As shown in Figures 3(b) and 4, the check valve 25 constituting the air supply valve 20 includes a cylindrical housing 251 having an inlet and consisting of a bottom wall and side walls, a valve 252 slidably held inside the housing 251, a cover 253 attached to the inlet of the housing 251 to hold the valve 252 inside the housing 251, and a biasing member 254 disposed inside the housing 251 to bias the valve 252 toward the inlet.

[0027] The check valve 25 is inserted into the main body 211 from the opening on the mounting side of the housing plug 21, with the inlet side leading. The cover 253 is positioned and placed in contact with the stepped portion 211a of the main body 211, and a ring-shaped sealing material 253a attached to the outer circumference of the cover 253 is mounted in contact with the inner circumference of the main body 211.

[0028] In its normal state, the check valve 25 closes the flow path when the sealing material 252a of the valve 252, which is biased toward the inlet side by the biasing member 254, comes into contact with the inner circumference of the cover 253. However, when fluid is supplied from the inlet side, as shown in Figure 10(b), the force of the fluid supplied from the inlet side causes the valve 252 to slide toward the outlet side against the biasing force of the biasing member 254, and the inlet and the flow holes 251a formed in the bottom wall and side wall of the housing 251 come into communication, allowing the fluid to pass through.

[0029] The housing 251, valve 252, and cover 253 that constitute the check valve 25 are not limited in material, but for example, resin materials such as ABS resin can be used. Similarly, the biasing member 254 that constitutes the check valve 25 is not limited in material, and can be made of metal or other materials. The configuration of the check valve 25 can be appropriately selected from known check valve configurations and is not particularly limited.

[0030] As shown in Figures 4 and 7, the flat packing 23 that constitutes the air supply valve 20 is a disc-shaped member having an opening in the center, and has a thick airtight portion 231, an outer peripheral flange portion 232 provided on the outer peripheral side of the airtight portion 231, and an inner peripheral flange portion 233 provided on the inner peripheral side of the airtight portion 231. The airtight portion 231 of the flat packing 23 protrudes in one direction relative to the outer peripheral flange portion 232 and the inner peripheral flange portion 233, and the airtight surface that contacts the purge nozzle or the like is formed in a flat shape.

[0031] The material of the flat packing 23 is not particularly limited, but materials such as fluororubber can be used.

[0032] The ring cushion 24 that constitutes the air supply valve 20 is a thick-walled cylindrical member, as shown in Figures 4 and 8. The material of the ring cushion 24 is not particularly limited, but an elastic material such as fluororesin foam can be used. Preferably, the material constituting the ring cushion has a rubber hardness (Asker C) of 30 or more and 42 or less.

[0033] As shown in Figures 4 and 9, the ring cover 22 constituting the air supply valve 20 has a bottom wall portion 221 with a circular opening 221a in the center, and a cylindrical tubular wall portion 222 that extends towards the mounting side along the outer circumference of the bottom wall portion 221, and as a whole it is a ring-shaped member. The material of the ring cover 22 is not particularly limited, but a resin material such as ABS resin can be used.

[0034] The cylindrical wall portion 222 of the ring cover 22 is formed by alternating thin-walled and thick-walled portions along its outer circumference. The thin-walled portion of the cylindrical wall portion 222 extends toward the mounting side to form an engaging portion 222a, and a claw portion 222b extending toward the inner circumference is provided at the tip of the engaging portion 222a on the mounting side. Additionally, a contact portion 222c is formed on the mounting side of the thick-walled portion, which contacts the side of the air intake port of the flange portion 213 of the housing plug 21.

[0035] Furthermore, the ring cover 22 may have the letters "IN" 221c inscribed on the side of the air intake port of the bottom wall portion 221 to indicate that the valve is an air intake valve. Furthermore, the bottom wall portion 221 of the ring cover 22 may have a hole 221b that aligns with the position of the engaging portion 222a of the cylindrical wall portion 222.

[0036] As shown in Figure 3(b), the air supply valve 20, consisting of the above components, is assembled by inserting a check valve 25 inside the main body portion 211 of the housing plug 21, attaching a ring cushion 24 and a flat packing 23 to the portion of the main body portion 211 closer to the air intake port than the flange portion 213, and attaching a ring cover 22 to cover the ring cushion 24 and the flat packing 23.

[0037] The ring cushion 24 is attached to the outer circumference of the main body portion 211 of the housing plug 21, and the mounting side of the ring cushion 24 is in contact with the flange portion 213 of the housing plug 21. Furthermore, the housing plug 21 may have a recess 213d formed on the air intake side of the flange portion 213, into which the mounting side of the ring cushion 24 fits.

[0038] The flat packing 23 is attached to the packing retaining portion 212 of the housing plug 21 with the ring cushion 24 attached to the outer circumference of the main body portion 211 of the housing plug 21, such that the airtight portion 231 protrudes toward the air intake port side. When the flat packing 23 is attached to the housing plug 21, it uses its elasticity to deform the inner circumferential flange portion 233 to overcome the retaining rib 212a, and then the inner circumferential flange portion 233 returns to its original state, thereby attaching to the packing retaining portion 212 of the housing plug 21.

[0039] A ring cover 22 is attached to the housing plug 21, which is fitted with a flat packing 23 and a ring cushion 24, from the air intake side.

[0040] The ring cover 22 is brought close to the housing plug 21 from the air intake side, and as shown in Figures 2 and 3, the elasticity of the engaging portion 222a causes the claw portion 222b to overcome the flange portion 213 and engage at the missing portion 213a, and the contact portion 222c of the cylindrical wall portion 222 of the ring cover 22 abuts against the air intake side of the flange portion 213 of the housing plug 21, thereby attaching it to the housing plug 21.

[0041] In the air supply valve 20, with the ring cover 22 attached to the housing plug 21, a space S surrounded by the ring cover 22 is formed on the outer circumference of the main body 211 of the housing plug 21, and the flat packing 23 and ring cushion 24 are housed within this space S.

[0042] In the air supply valve 20, the air intake port 20a of the housing plug 21 is exposed from the opening 221a of the ring cover 22, and the airtight portion 231 of the flat packing 23, which has a planar airtight surface, surrounds the air intake port 20a, with the airtight portion 231 protruding from the opening 221a of the ring cover 22 toward the air intake port.

[0043] In the air supply valve 20, an elastic ring cushion 24 is positioned on the mounting side of the flat packing 23, thereby biasing the flat packing 23 toward the air intake port side of the packing holding portion 212. The flat packing 23, positioned within space S so as to be biased toward the air intake side of the packing retaining portion 212, has its inner circumferential flange portion 233 in contact with the retaining rib 212a of the packing retaining portion 212, and its outer circumferential flange portion 232 in contact with the bottom wall portion 221 of the ring cover 22, with the airtight portion 231 protruding from the opening 221a toward the air intake side.

[0044] The configuration of the air intake valve 20 in this embodiment has been described above. In order to form it as an exhaust valve 30, for example, as shown in Figure 6, the orientation of the check valve 25 located inside the housing plug 21 can be reversed, and if necessary, letters such as "OUT" may be written in appropriate places. Furthermore, the dimensions of each component, such as the housing plug 21 and the ring cover 22, may be adjusted as needed according to the usage conditions. Furthermore, for product management purposes, the housing plugs 21 and ring covers 22 of the intake valve 20 and exhaust valve 30 may be made in different colors.

[0045] The air supply valve 20 described above is attached to the bottom surface of the circuit board storage container B by screwing the threads 211d formed on the outer circumference of the main body 211 of the housing plug 21 into the mounting holes 12a formed in the bottom plate 12 of the container body 1 of the circuit board storage container B. At this time, the air supply valve 20 can be installed at an appropriate height by limiting further screwing when the pair of protrusions 213b, 213b provided on the flange portion 213 of the housing plug 21 come into contact with the bottom surface of the substrate storage container B. Furthermore, when installing the air supply valve 20, it is preferable to place a ring-shaped airtight material on the mounting side of the flange portion 213 of the housing plug 21 to create an airtight seal between the mounting side of the air supply valve 20 and the bottom plate 12, and it is also preferable to place a filter between the air supply valve 20 and the mounting hole 12a as appropriate.

[0046] When the substrate storage container B, to which the air supply valve 20 is attached, is installed and positioned in the lid opening / closing device, as shown in Figure 10(a), the air supply valve 20 is connected to the purge nozzle C1 of the purge device, and the inert gas supplied from the purge nozzle C1 is supplied into the substrate storage container B through the air supply port 20a of the air supply valve 20.

[0047] At this time, the air supply valve 20 connected to the purge nozzle C1 has the airtight portion 231 of the flat packing 23 protruding from the opening 221a of the ring cover 22 so as to surround the air supply port 20a, and the airtight surface of the airtight portion 231 is flat, so the airtight portion 231 is in close contact with the purge nozzle C1 over a wide area, and leakage of inert gas from the connection can be suppressed.

[0048] Furthermore, the air supply valve 20 has a flat packing 23 that contacts the purge nozzle C1, which is made of relatively hard fluororubber. This prevents damage caused by contact with the purge nozzle C1, and allows the valve to maintain airtightness over a long period of time.

[0049] Furthermore, when the airtight portion 231 of the flat packing 23 is pressed against the surface of the purge nozzle C1, as shown in Figure 10(b), the ring cushion 24 positioned on the mounting side of the flat packing 23 compresses in the space S due to its elasticity, thereby allowing the flat packing 23 to slide toward the mounting side (arrow y).

[0050] Therefore, even if the height dimensions of the multiple purge nozzles of the purge device are different, for example, as shown in Figure 10(a), if the height dimension t1 of the supply-side purge nozzle C1 and the height dimension t2 of the exhaust-side purge nozzle C2 are different, the flat packing 23 of the valve (supply valve 20) that abuts the supply-side purge nozzle C1, which has a higher height dimension t1, slides in accordance with the height position of the purge nozzle C1, and the flat packings 23 of both valves can always be kept in close contact.

[0051] -Effects of the high-airtightness valve of this embodiment- In this embodiment, the air supply valve (high-airtight valve) 20 has a flat packing 23 with a large contact area that surrounds the air supply port 20a and contacts the purge nozzle C1 of the purge device to create an airtight seal. This ensures high airtightness and suppresses leakage of inert gas.

[0052] In this embodiment, the air supply valve (high-airtight valve) 20 has a flat packing 23 that seals the area around the air supply port 20a made of hard fluororubber, which makes the airtight part 231 itself less susceptible to damage and allows the airtight performance to be maintained over a long period of time.

[0053] In this embodiment, the air supply valve (high-airtight valve) 20 has a flat packing 23 that is slidably held, and an elastic cushioning material made of fluororesin foam or the like is arranged on the mounting side of the flat packing 23. Therefore, even if there are height differences between the multiple purge nozzles provided in the purge device due to manufacturing tolerances, the flat packing 23 of each valve can be made to follow each purge nozzle and be tightly sealed, thereby maintaining high airtightness performance overall.

[0054] -Variations- In the air supply valve 20 of this embodiment, the ring cover 22 is configured to engage with the housing plug 21 by having six engaging portions 222a provided at equal intervals along the outer circumference. However, the number and position of the engaging portions 222a of the ring cover 22 are not limited, and furthermore, the mounting structure of the ring cover 22 to the housing plug 21 is not limited.

[0055] Furthermore, when attaching the air supply valve 20 or exhaust valve 30 to the substrate housing container B, the valve can be directly attached to the mounting holes 12a and 12b formed in the bottom plate 12 of the container body 1, but if necessary, it may also be attached via an attachment fitted to the mounting hole 12a.

[0056] It goes without saying that the embodiments described above are not intended to limit the inventions described in the claims, but are to be treated as illustrative examples. [Explanation of Symbols]

[0057] 20: Intake valve 20a:Air supply port 21: Housing Plug 211: Main body 213: Flange section 22: Ring cover 221a:Aperture 23: Flat packing 24: Ring cushion 25: Check valve

Claims

1. The device comprises a housing plug, a check valve disposed inside the housing plug, a flat packing that airtightly seals the area around the intake and exhaust ports, an elastic ring cushion, and a ring cover attached to the housing plug that covers the flat packing and the ring cushion. The housing plug has a main body portion having a flow path leading to the intake and exhaust port and a check valve arranged in the flow path, and a flange portion extending outward from the main body portion. The ring cover engages with the flange portion of the housing plug and has an opening that exposes the intake and exhaust port of the housing plug. The flat packing is slidably held on the outer circumference of the main body of the housing plug, has a planar airtight surface surrounding the intake and exhaust port, and protrudes from the opening. The ring cushion is a high-airtight valve positioned on the outer circumference of the main body of the housing plug, between the flat packing and the flange portion of the housing plug.

2. The flat packing is made of fluororubber, The ring cushion is formed of fluororesin foam. The airtight valve according to claim 1.

3. A substrate storage container equipped with a high-airtight valve according to claim 1 or claim 2.

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