JP6150388B2 - Gate valves and chambers - Google Patents

Description

  The present invention relates to a gate valve and a chamber including the gate valve, and more particularly, to an improved structure for reducing particles and emitted gas generated during gate valve operation.

  In recent years, due to the fact that semiconductor process rules are miniaturized and the accuracy of organic EL displays and the like is increased, demands for reducing particles and emitted gas have become stricter in these manufacturing apparatuses. Along with this, the gate valve used in the manufacturing apparatus is also required to have low particles and low emission gas.

  Conventionally, as an example of a gate valve used in this type of manufacturing apparatus, a gate valve disclosed in Patent Document 1 below is known. In this gate valve, an inverted U-shaped bent portion is formed at an end portion of the valve restraint, and a recessed portion that fits at the tip of the bent portion is formed in the valve seat wall. As a result, when the valve plate is pressed against the valve seat, the inverted U-shaped bent portion is received in the recess, and the valve restrainer can be prevented from moving away from the valve seat.

  In such a gate valve, for example, particles are generated due to wear during contact at the contact portion between the sealing material provided on the valve plate and the valve seat, or at the contact portion between the inverted U-shaped bent portion and the recess, It becomes a factor of emission gas generation. In particular, in the gate valve of Patent Document 1, since a groove and a ball or a link is used as a mechanism for pressing the valve plate against the valve seat, the orbit when the sealing material is joined to the valve seat is a circular orbit. The sealing material is rubbed against the valve seat in accordance with the trajectory, and particles are easily generated. In addition, even in the contact portion between the inverted U-shaped bent portion and the concave portion, the metal is rubbed by the same track to generate particles. Further, grease for lubrication is used for the mechanism and the ball bearing or roller, or the link mechanism, and this also causes emission gas.

Japanese Patent No. 3388439

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a gate valve capable of greatly reducing particles and emitted gas generated during valve operation, and a chamber including the gate valve. Is to provide.

In order to achieve the above object, the gate valve according to the present invention is a gate valve in which a seal unit is operated by a linear actuator built between an opposing seal plate and a back plate to open and close the opening. Is received by a reaction force when pressed against the sealing surface of the opening, and the buffer member provided on the upper portion of the back plate is joined to the upper stopper installed in the chamber, or the back plate When the upper part is joined to a buffer member provided on an upper stopper installed in the chamber, the valve rod connected to the back plate is elastically deformed in an arcuate shape, and the lower part of the back plate is directed toward the opening. An extending lower stopper is provided, and the recess or hole formed in the lower stopper A convex portion formed at the lower portion of the seal flange on the seal surface is fitted through a buffer member, or a convex portion formed on the lower stopper is a concave portion or hole formed at the lower portion of the seal flange on the seal surface. By being fitted to each other via a buffer member, a reaction force is received when the seal plate is pressed against the seal surface .

  In the gate valve having the above structure, the lower stopper may be fixed to the valve rod and detachable from the back plate.

  In the gate valve having the above-described structure, the seal unit includes an opening / closing cylinder having a piston that expands and contracts by air pressure supply and exhaust, and a supply for transmitting the opening operation pressure and the closing operation pressure to which the opening / closing cylinder is fixed. A back plate having a discharge path and a seal plate coupled to the rod portion of the piston are provided. A check valve is provided in the open / close cylinder, and an internal pressure applied to the bellows covering the rod portion is A bellows protection structure may be provided that discharges the internal pressure to the outside of the seal unit through the check valve when a reference pressure is exceeded.

Further, the chamber according to the invention, equipped with a gate valve comprising a structure of any of the, with maintenance port for taking out the sealing unit in the gate valve to the chamber is provided, the maintenance eggplant port The port cover to be closed has a function of an upper stopper for joining with the back plate .

  According to the present invention, when the seal plate is driven by the linear motion actuator and the seal plate is pressed against the seal surface, the upper part of the back plate and the upper stopper are joined via the buffer member, so The impact force of is reduced. Further, when the back plate moves backward in the non-sealing direction due to the reaction force at the time of sealing, the valve rod is elastically deformed in an arcuate shape, so that the speed is reduced, so that the impact force at the time of joining is reduced. Therefore, damage to the joint portion between the back plate and the upper stopper can be suppressed, and generation of particles and emitted gas can be prevented. In addition, since the seal material is not rubbed against the seal surface by combining the linear actuator and the buffer member, generation of particles and released gas due to friction can be prevented.

It is sectional drawing which shows an example of the gate valve of this invention. (A) is sectional drawing which shows the state which raised the seal unit in the gate valve of FIG. 1 to the closed position, (b) is sectional drawing which shows the closed state of the sealing surface by the seal unit. (A) is sectional drawing which shows the modification which provided the lower stopper in the gate valve of this invention, (b) is sectional drawing which shows the state which raised the seal unit in the gate valve to the closed position. (A) is sectional drawing which shows the modification of the lower stopper in the gate valve of FIG. 3, (b) is sectional drawing which shows the state which raised the seal unit in the gate valve to the closed position. It is sectional drawing which shows the modification of the port cover in the chamber carrying the gate valve of this invention. (A) is sectional drawing which shows the bellows protection structure of the seal unit in the gate valve of this invention, (b) is an enlarged view of the non-return valve in the protection structure. (A) is the whole figure which shows the guide apparatus of the existing gate valve, (b) is arrow sectional drawing of the figure (a). (A) is the whole figure which shows the guide apparatus of the gate valve of this invention, (b) is arrow sectional drawing of the figure (a).

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the gate valve 1 of this embodiment is used in a high vacuum semiconductor manufacturing apparatus, FPD manufacturing apparatus, and the like, and includes a valve rod 2, a bellows 3, a seal unit 4, and a guide device 5. Configured. In the present embodiment, a direct mount structure that is directly mounted on the chamber 6 of the transfer chamber or the reaction chamber without using a valve case is adopted, which eliminates the need for the valve case, thereby reducing costs, downsizing the apparatus, Effects such as reduction of maintenance points can be obtained.

  The valve rod 2 is covered with a stretchable metal bellows 3 such as a welded bellows or a molded bellows, and the guide device 5 is driven while isolating the vacuum space inside the chamber 6 from the outside atmospheric environment. The seal unit 4 is moved up and down inside the chamber 6. The number of valve rods 2 and bellows 3 is provided in one or more sets depending on the width of the opening 7 provided in the chamber 6.

  The seal unit 4 is connected to the valve rod 2 and is accurately guided to a fixed position by a guide device 5 to be described later without wobbling. That is, at the time of sealing, the valve rod 2 is first lifted by driving the guide device 5, and the seal unit 4 is guided to the height position (closed position) of the opening 7 of the chamber 6 as shown in FIG. Next, the seal plates 8 arranged opposite to each other are expanded by the operation of the linear motion actuator 10 fixed to the back plate 9, and the seal plate 8 is placed on the seal surface 12 of the seal flange 11 as shown in FIG. Press to seal.

  In a direct mount structure that does not use a valve case as in the present embodiment, in the gate valve in which the seal unit 4 includes the direct acting actuator 10, some regulation means is required inside the chamber 6. Therefore, in this embodiment, one or a plurality of upper stoppers 14 are detachably attached to the chamber side plate 13, and the seal plate 8 is pressed against the seal surface 12 by the recess 15 provided in the upper stopper 14. Receives reaction force.

  Here, the location where particles are generated in the gate valve 1 of the present embodiment is conspicuous in the contact portion between the seal material (for example, O-ring) 16 embedded in the seal plate 8 and the seal surface 12, or particularly in the large gate valve. A stopper mechanism for receiving the surface pressure applied to the seal plate 8 and the like, and the location where the released gas is generated is a linear actuator 10 built in the seal unit 4. This emission gas source is also a particle source.

  Therefore, in the present embodiment, the emission gas generation source is covered with the bellows 3, thereby suppressing the generation of the emission gas to the limit, and particles generated from the same generation source as the emission gas can be enclosed in the bellows 3. it can. In particular, in the case of a large gate valve, a very large surface pressure is applied at the time of sealing. Therefore, in this embodiment, a buffer member 17 made of resin, rubber, or the like is provided on the upper portion of the back plate 9 that contacts the upper stopper 14. It has been. Therefore, the reaction plate receives the reaction force when the seal plate 8 is pressed against the seal surface 12, and the upper part of the back plate 9 is joined to the recess 15 of the upper stopper 14 via the buffer member 17. The impact force at the time of joining is reduced, and generation of particles due to peeling of the surface of the back plate 9 and the upper stopper 14 can be suppressed.

  In the present embodiment, when the seal unit 4 is moved to the closed position as shown in FIG. 2A, the reaction force absorbing gap g between the upper portion of the back plate 9 and the concave portion 15 of the upper stopper 14 is obtained. Is formed. Then, as shown in FIG. 2B, the buffer member 17 provided on the upper portion of the back plate 9 is joined to the concave portion 15 of the upper stopper 14 by receiving a reaction force when the seal plate 8 is pressed against the seal surface 12. When doing so, the valve rod 2 connected to the back plate 9 bends away from the seal surface 12 and is elastically deformed into an arcuate shape.

  That is, when the seal plate 8 is driven by the linear motion actuator 10 and the back plate 9 moves backward in the non-seal direction due to the reaction force at the time of sealing, the speed is reduced by the elastic force of the valve rod 2 and the reaction force is reduced. Since it disperses, the impact force during joining and the seal plate pressing force applied to the stopper are alleviated. Therefore, damage to the joint portion between the buffer member 17 and the recess 15 on the upper portion of the back plate 9 can be suppressed, the generation of particles can be greatly suppressed, the life of the buffer member can be extended, and the maintenance cycle can be extended. In this regard, in a conventional link type or a seal unit that employs a structure in which a load is not applied to an existing actuator and rod, it is difficult to control the speed at the time of joining, and damage to the joined part and frequent maintenance are inevitable.

  In the case of a link-type actuator, particles are generated because a mechanical sliding operation occurs when the sealing material 16 of the seal plate 8 is joined to the seal surface 12. However, in this embodiment, the rod portion 30 of the linear actuator 10 is protected by the bellows 31 and is isolated from the vacuum portion, so there is no sliding portion, and generation of particles due to friction can be suppressed.

  In addition, according to the link type actuator, there is a stroke limitation, and when the amount of elastic deformation is reduced due to plastic deformation or wear due to deterioration of the seal material 16 of the seal plate 8, the seal performance is lowered accordingly. On the other hand, by using the linear actuator 10 as in this embodiment, even if the elastic deformation amount of the sealing material 16 is reduced, it can be pressed against the sealing surface 12 by that amount. There is also an advantage that it leads to stabilization of performance (followability is generated for the stroke of the opening and closing cylinder).

  In the case of such a gate valve 1, a by-product attached to the seal unit 4 or the seal material 16 during the manufacture of a semiconductor, FPD, or the like is one of the factors for generating particles. Therefore, in the present embodiment, a maintenance port 18 is provided in the upper part of the valve unit installed in the chamber 6. Thus, the seal unit 4 can be replaced by removing the port cover 19 that covers the maintenance port 18 and removing the upper stopper 14 attached to the chamber side plate 13. Therefore, maintenance work such as removing by-products attached to the seal unit 4 and the seal flange 11 can be easily performed.

  Although the gate valve 1 of the present embodiment is configured as described above, the following structure may be adopted as a modification thereof.

  For example, the gate valve 1 shown in FIG. 3 is characterized in that another type of stopper is provided in addition to the upper stopper 14 described above. That is, as shown in FIG. 3A, a lower stopper 20 extending toward the opening 7 is provided integrally or separately at the lower portion of the back plate 9. A circular hole 21 is formed. In addition, a pin-shaped convex portion 22 that fits into the hole 21 is provided at the lower portion of the seal flange 11 at a position facing this, and resin or rubber is provided on the outer peripheral surface of the convex portion 22 on the opening side. A shock-absorbing member 23 is attached. Since the other structure is the same as that shown in FIG. 1, the same members are denoted by the same reference numerals and detailed description thereof is omitted.

  According to such a structure, when the seal unit 4 is guided to the closed position of the opening 7 by driving the guide device 5 as shown in FIG. 20 holes 21 are fitted. When the seal plate 8 is pressed against the seal surface 12 by the operation of the linear actuator 10, the reaction force is applied to the valve rod 2 by the lower stopper 20 absorbing the reaction force through the buffer member 23 by the fitting. The pressure to do is reduced. Therefore, according to the gate valve 1 of the present embodiment, since the two types of stopper structures of the upper stopper 14 and the lower stopper 20 are employed, the low rigidity of the valve rod 2 can be achieved by the distribution of the impact force to the shock absorbing member. As a result, it is possible to realize cost reduction, weight reduction, speed-up, and the like.

  The gate valve 1 shown in FIG. 4 employs two types of stopper structures, an upper stopper 14 and a lower stopper 20 as in FIG. 3, but the lower stopper 20 is attached and fixed around the valve rod 2. And the lower stopper 20 is provided so as to be separable from the back plate 9. Since the other structure is the same as the structure shown in FIG. 3, the same members are denoted by the same reference numerals and detailed description thereof is omitted.

  According to such a structure, when performing the maintenance work as described above, the seal flange 11 is not obstructed by separating the lower stopper 20 from the back plate 9 when the seal unit 4 is taken out from the maintenance port 18. Only the seal unit 4 can be taken out while the lower stopper 20 remains in the chamber 6. Therefore, according to the gate valve 1 of the present embodiment, in addition to the above effects, there is an effect that the replacement work of the seal unit 4 can be performed efficiently.

  Further, the gate valve 1 shown in FIG. 5 is characterized in that the structure of the port cover 19 is modified. In the present embodiment, the concave portion 15 is integrally formed on the back surface of the lid portion of the port cover 19 so that the port cover 19 functions as a lid that closes the maintenance port 18 and the reaction force at the time of sealing with the back plate 9 is sealed. It has the function as the upper stopper 14 to receive. The stopper / port cover 24 is attached and fixed not to the chamber side plate 13 but to the chamber top plate 25 provided with the maintenance port 18.

  According to such a structure, when removing the seal unit 4 from the maintenance port 18, it is not necessary to perform the work of removing the two parts of the port cover 19 and the upper stopper 14 as described above. All you have to do is remove it. For this reason, the replacement work of the seal unit 4 can be performed more easily and in a short time during maintenance. In addition, since the number of parts can be reduced, it is possible to reduce the cost of the entire apparatus. Although not shown, the port cover 19 and the upper stopper 14 may be disassembled. If disassembly is possible, the number of parts increases, but replacement becomes possible at a low cost when the upper stopper 14 breaks down.

  Next, the structure of the seal unit 4 in the gate valve 1 described above will be described in detail. As shown in FIG. 6 (a), the seal unit 4 is an open / close cylinder that opens and closes the seal plate 8 in the direction of the arrow as a linear motion actuator 10 between a seal plate 8 and a back plate 9 that are arranged to face each other. 26. The open / close cylinder 26 includes a piston 29 that expands and contracts by supplying and exhausting air pressure in a sealed space formed by a cylinder body 27 and a cylinder lid 28 fixed to the back plate 9, and the rod portion 30 of the piston 29 is sealed. It is connected to the plate 8. In addition, a bellows 31 made of metal such as a welded bellows or a molded bellows is attached so as to cover the periphery of the rod portion 30.

  During the opening operation by the opening / closing cylinder 26, the compressed air (closing operation pressure) inside the closing operation pressure supply chamber 33 is discharged from the closing operation pressure supply port 32 of the back plate 9, and at the same time, the opening operation pressure of the back plate 9 is increased. Compressed air (open operation pressure) is supplied from the supply port 34 to the open operation pressure supply chamber 35 through the supply / discharge passage. As a result, the inside of the opening operation pressure supply chamber 35 is pressurized, the piston 29 is pressed toward the back plate 9, the rod portion 30 is retracted, and the seal plate 8 coupled to the rod portion 30 is separated from the seal surface 12. Thus, the opening 7 is opened. This is the valve open state.

  On the other hand, during the closing operation by the opening / closing cylinder 26, the compressed air (opening operation pressure) inside the opening operation pressure supply chamber 35 is discharged from the opening operation pressure supply port 34 of the back plate 9, and simultaneously the closing operation pressure of the back plate 9 is closed. Compressed air (closed operation pressure) is supplied from the supply port 32 to the closed operation pressure supply chamber 33 through the supply / discharge path. As a result, the inside of the closing operation pressure supply chamber 33 is pressurized, the piston 29 is pressed in the direction of the seal plate 8, the rod portion 30 moves forward, and the seal plate 8 coupled to the rod portion 30 is pressed against the seal surface 12. As a result, the opening 7 is closed. This is the closed state of the valve.

  Further, since the chamber 6 transfer chamber or the reaction chamber is normally kept in a vacuum state, the opening operation pressure that leaks minutely from the opening operation pressure supply chamber 35 through the sliding gap of the rod portion 30 is transferred to the chamber 6. The periphery of the rod portion 30 is covered with a bellows 31 so as not to diffuse into the chamber or the reaction chamber. In this way, the inner and outer spaces of the open / close cylinder 26 are completely separated by the bellows 31 and the respective airtight states are maintained, so that it is possible to prevent the atmosphere from entering the chamber 6 transfer chamber or the reaction chamber.

  Furthermore, in this embodiment, a poppet mechanism is employed as a structure for protecting the bellows 31. That is, the first check valve 36 is built in the piston 29, one end thereof communicates with the inside of the bellows 31, and the other end communicates with the closing operation pressure supply chamber 33. A second check valve 37 is built in the cylinder lid 28, and one end thereof communicates with the inside of the bellows 31, and the other end communicates with the opening operation pressure supply chamber 35. As shown in FIG. 6B, the first check valve 36 and the second check valve 37 include a valve body 38 having a seal portion, and a compression spring that urges the valve body 38 toward the valve seat 39. 40.

  When the internal pressure applied to the bellows 31 exceeds the reference pressure during the opening operation (when the inside of the opening operation pressure supply chamber 35 is pressurized), the second check valve 37 is closed. At this time, the reference pressure in the bellows 31 is closed. Compressed air exceeding the pressure passes through the passage in the rod portion 30 and pushes down the valve body 38 against the compression spring 40 to open the first check valve 36. As a result, the compressed air is discharged from the closing operation pressure supply chamber 33 to the outside of the seal unit 4 through the closing operation pressure supply port 32.

  On the other hand, if the internal pressure applied to the bellows 31 exceeds the reference pressure during the closing operation (when the inside of the closing operation pressure supply chamber 33 is pressurized), the first check valve 36 is closed at this time. The compressed air exceeding the reference pressure passes through the passage in the cylinder lid 28, and pushes down the valve body 38 against the compression spring 40 to open the second check valve 37. As a result, the compressed air is discharged from the opening operation pressure supply chamber 35 to the outside of the seal unit 4 through the opening operation pressure supply port 34.

  As described above, according to the gate valve 1 of the present embodiment, the pressure between the rod portion 30 and the bellows 31 is detected by the two check valves 36 and 37, and a pressure exceeding a certain pressure is applied to the bellows 31. Then, either one of the check valve 37 and the check valve 38 is automatically opened according to the pressure state inside the linear actuator 10, and the compressed air is discharged to the outside of the seal unit 4, thereby Deformation and damage can be prevented in advance. Therefore, it is possible to prevent contamination and vacuum breakage due to the rupture of the bellows 31 and improve the life of the gate valve 1 including the seal unit 4.

  Finally, the structure of the guide device 5 in the gate valve 1 described above will be described in detail. FIG. 7 shows an existing guide device 5A. This guide device 5A has a built-in drive mechanism for moving the seal unit 4 by the valve rod 2, and as shown in FIG. The plurality of rollers 43, 43,... According to this existing guide device 5A, a separate support mechanism for supporting the guide mechanism is required inside the device, which causes an increase in size, weight, and cost of the device.

  On the other hand, FIG. 8 shows a guide device 5B according to the present invention. In this guide device 5B, the guide mechanism that guides the lifting and lowering operation of the valve rod 2 without using the roller 43 as a drive mechanism for moving the seal unit 4 by the valve rod 2 is the same as the support mechanism that supports the guide mechanism. The column 44 is constituted. Moreover, the support | pillar 44 is shape | molded by the column shape, and the slide bearing which uses the bush 45 for the outer diameter of the support | pillar 44 is provided. According to this new guide device 5B, the guide mechanism and the support mechanism, which have been provided separately in the past, can be shared by a single column 44, the structure of the guide device 5B becomes extremely simple, and the entire device is made compact. Effects such as weight reduction and cost reduction can be obtained.

  The embodiment described above is merely an example, and the design can be changed as appropriate without departing from the scope of the present invention. For example, although the gate valve 1 is mounted in the chamber 6 of the reaction chamber, the present invention is not limited to this and can be mounted in the chamber 6 of the transfer chamber. Further, although the buffer member 17 is provided on the upper portion of the back plate 9, the buffer member 17 may be provided in the concave portion 15 of the upper stopper 14 instead.

  Further, in FIG. 3 and FIG. 4, the hole 21 is formed at the tip of the lower stopper 20, and the convex portion 22 is formed at the lower portion of the seal flange 11, but conversely, the convex portion 22 is formed at the tip of the lower stopper 20. The hole 21 may be formed in the lower part of the seal flange 11, and a recess may be formed instead of the hole 21. In FIG. 4, the lower stopper 20 is fixed to the valve rod 2 so that the seal unit 4 can be separated and removed. Instead, the maintenance port 18 is expanded in the non-seal direction, so that the seal flange 11 is The seal unit 4 can be easily taken out by avoiding it.

1: Gate valve 2: Valve rod 3: Bellows 4: Seal unit 5: Guide device 6: Chamber 7: Opening 8: Seal plate 9: Back plate 10: Direct acting actuator 11: Seal flange 12: Seal surface 13: Chamber Side plate 14: Upper stopper 15: Recess 16: Sealing material 17: Buffer member 18: Maintenance port 19: Port cover 20: Lower stopper 21: Hole 22: Protruding portion 23: Buffer member 24: Stopper / port cover 25: Chamber top plate 26: Opening and closing cylinder 27: Cylinder body 28: Cylinder lid 29: Piston 30: Rod part 31: Bellows 32: Close operation pressure supply port 33: Close operation pressure supply chamber 34: Open operation pressure supply port 35: Open operation pressure supply chamber 36: First check valve 37: Second check valve 38: Valve element 39: Valve seat 0: compression spring 41: Battledore shape of strut 42: groove 43: roller 44: cylindrical pillar 45: bushing

Claims (4)

In a gate valve that opens and closes an opening by a seal unit operated by a linear actuator built between an opposing seal plate and a back plate,
In response to the reaction force when the seal plate is pressed against the seal surface of the opening,
When the buffer member provided on the upper portion of the back plate is joined to the upper stopper installed in the chamber, or
When the upper part of the back plate is joined with a buffer member provided in an upper stopper installed in the chamber,
The valve rod connected to the back plate is elastically deformed in a bow shape ,
A lower stopper extending in the direction of the opening is provided at the lower part of the back plate,
A convex part formed at the lower part of the seal flange of the sealing surface is fitted to the concave part or hole formed in the lower stopper via a buffer member, or
By fitting the convex part formed in the lower stopper to the concave part or hole formed in the lower part of the seal flange of the sealing surface via a buffer member,
A gate valve characterized by receiving a reaction force when the seal plate is pressed against the seal surface . The gate valve according to claim 1 , wherein the lower stopper is fixed to the valve rod and is detachable from the back plate . The seal unit is
An open / close cylinder with a piston that expands and contracts when air pressure is supplied and exhausted;
A back plate having a supply / discharge path to which the open / close cylinder is fixed and which transmits an opening operation pressure and a closing operation pressure;
A seal plate coupled to the rod portion of the piston,
A check valve is provided in the open / close cylinder, and when the internal pressure applied to the bellows covering the rod portion exceeds a reference pressure, the bellows protection structure for discharging the internal pressure to the outside of the seal unit through the check valve. gate valve according to claim 1 or 2, characterized in that it comprises. A chamber equipped with the gate valve according to any one of claims 1 to 3 , wherein the chamber is provided with a maintenance port for taking out a seal unit in the gate valve ,
A chamber characterized in that a port cover for closing the maintenance port also has a function of an upper stopper for joining with the back plate .