JP5958446B2 - Load port device - Google Patents

Description

  The present invention relates to a load port device. More specifically, the present invention relates to a load port device that opens and closes a pod when a wafer held in a sealed transfer container called a pod is transferred to a semiconductor processing apparatus in a semiconductor manufacturing process or the like.

  In the semiconductor manufacturing process, the so-called yield in the process is improved by highly cleaning the inside of the pod that accommodates the wafer and the inside of the micro space in which the wafer is inserted into and removed from the pod and delivered to each processing apparatus. ing. However, in an environment using so-called air in which dust or the like is simply removed, it is inevitable that a natural oxide film is formed on the wafer surface or various wirings formed on the wafer. For this reason, as shown in Patent Document 1, by filling the inside of the pod with nitrogen as an inert gas, suppression of the generation of a natural oxide film at the time of pod conveyance or the like is achieved. According to the configuration exemplified in Patent Document 1 that performs injection and discharge of an inert gas or the like with respect to the pod, the partial pressure of the oxidizing gas can be suppressed by suitably replacing the gas in the pod.

JP 2011-187539 A

  The nozzle mechanism for gas injection and discharge disclosed in the cited document 1 is arranged at the lower part of the mounting table on which the pod is mounted, and the mounting table is placed at the position with respect to the opening of the load port. A drive mechanism for the mounting table is also arranged for approaching or separating. Since individual configurations and mechanisms are accompanied by wiring, piping, and the like, it is desirable that the main configuration be miniaturized as much as possible for maintenance and the like. The nozzle mechanism is covered by a so-called lower cover disposed at the bottom of the mounting table, together with a door drive system that opens and closes the opening of the load port and inserts and removes the pod lid. Since the area covered by the lower cover is connected to the minute space via the door drive system, there is a possibility that it becomes difficult to manage the cleanliness of the minute space when an area where gas is retained is generated by these configurations. Therefore, from this point of view, it is preferable that the configuration disposed under the mounting table is downsized. Since the nozzle mechanism disclosed in the cited document 1 requires a plurality of air cylinders, a nozzle, and a mechanism for connecting the air cylinder and the nozzle, there is a difficulty in miniaturization.

  The present invention has been made in view of the above situation, and is a load port that can be further reduced in size and can supply and discharge a suitable gas to and from a pod mounted on a mounting table. The purpose is to provide a device.

In order to solve the above-described problem, the load port device according to the present invention enables opening and closing of the lid of the pod to allow insertion / removal of the object to be processed with respect to the pod. A load port device capable of transporting the workpiece to the processing device;
A mounting table on which the pod is mounted;
A cylindrical gas flow nozzle having a flange and one opening located on the mounting table,
A housing portion having a pressure chamber through which the gas flow nozzle penetrates in the axial direction and separated into a first pressure adjustment chamber and a second pressure adjustment chamber by the flange portion;
A gas circulation chamber in which the other opening of the gas circulation nozzle is opened inside, and the positional relationship with the pressure chamber is fixed;
Differential pressure generating means for generating a differential pressure between the first pressure adjusting chamber and the second pressure adjusting chamber and moving the gas flow nozzle in the axial direction by applying the differential pressure to the flange portion. It is characterized by having.

  In the above-described load port device, it is preferable that the gas circulation chamber has a size including a movement range of the other opening when the gas circulation nozzle moves in the axial direction due to the differential pressure. The differential pressure generating means adjusts the internal pressure by supplying and discharging gas to and from the second pressure adjusting chamber disposed on the one opening side in the axial direction. It is more preferable to have a pressure adjusting means.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to perform supply and discharge | emission of suitable gas with respect to the pod mounted in the mounting base by the gas supply / discharge mechanism in which size reduction is possible.

It is a conceptual diagram of the gas supply and discharge mechanism arranged in the load port device according to the first embodiment of the present invention. About the conceptual diagram shown in FIG. 1, it is a figure which shows typically the internal structure of the gas supply direction cross section of the said gas supply and discharge mechanism. It is a figure which shows typically the main structure of the load port apparatus which has a gas supply / discharge mechanism shown in FIG. 2, and the pod mounted in this. It is a figure shown in the same style as FIG. 3 about the main structures of the load port apparatus which has the conventional gas supply / discharge mechanism. It is a figure which shows typically the state in each stage about raising / lowering of the nozzle in the gas supply / discharge mechanism shown in FIG.

  An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram of a gas supply / discharge mechanism used in a load port device according to a first embodiment of the present invention. FIG. 2 schematically shows an example of the internal configuration of the gas supply / discharge mechanism. In more detail, in FIG. 2, the schematic structure in the cross section about the gas flow direction at the time of supplying gas to a pod in the said gas supply / exhaust mechanism is shown. FIG. 3 is a diagram schematically showing the main configuration of the load port apparatus having the gas supply / discharge mechanism shown in FIG. 2 and the pod placed thereon.

  As shown in FIG. 1, the gas supply / discharge mechanism 10 in this embodiment includes a gas flow nozzle 3, a housing part 7, a gas flow chamber 11, and a differential pressure generating means 15. The gas flow nozzle 3 has a cylindrical shape having one opening 3a and another opening 3b, and forms a gas flow path 3c that connects the one opening 3a and the other opening 3b in the axial direction of the cylindrical shape. . Further, the gas flow nozzle 3 has a flange-like flange portion 5 that projects in a direction different from the axial direction, in the present embodiment, a perpendicular direction.

  The housing part 7 through which the gas flow nozzle 3 penetrates in the axial direction has a pressure chamber 9. The pressure chamber 9 is separated and defined by the flange portion 5 into a first pressure adjustment chamber 9a and a second pressure adjustment chamber 9b. Further, the pressure chamber 9 is slid in the axial direction in a state where the outer peripheral surface of the flange portion 5 maintains chamber separation in the vicinity of the inner peripheral surface of the chamber when the gas flow nozzle 3 moves in the axial direction. It has a width and an axial length that allow movement. The gas circulation chamber 11 is arranged in a state where the positional relationship with the pressure chamber 9 is fixed, and the other opening 3b of the gas circulation nozzle 3 is located in the chamber. A gas supply / discharge pipe 13 from a gas supply / discharge system (not shown) is connected to the gas circulation chamber 11. The gas supplied into the pod (not shown) via the gas distribution nozzle 3 or the gas discharged from the pod through the gas distribution nozzle 3 is the gas distribution chamber disposed between the gas supply and discharge system. 11 is temporarily retained here as a buffer space.

  In the present embodiment, the pressure adjusting path 17 is connected to the second pressure adjusting chamber 9b. The pressure adjusting path 17 is connected to a vacuum system 17a and a pressurized air supply system 17b (see FIG. 2), and the pressure in the second pressure adjusting chamber 9b can be increased or decreased. By exhausting the gas in the second pressure adjusting chamber 9b through the pressure adjusting path 17, the air pressure in the second pressure adjusting chamber 9b is made smaller than the air pressure in the first pressure adjusting chamber 9a. To generate differential pressure. The differential pressure generates an urging force for the gas flow nozzle 3 toward the axial first opening 3a, that is, in the direction of arrow B in the figure with respect to the flange portion 5, and the gas flow nozzle 3 itself moves in the direction of arrow B. Let Further, by supplying pressurized air into the second pressure regulating chamber 9b, the atmospheric pressure in the second pressure regulating chamber 9b is made larger than the atmospheric pressure in the first pressure regulating chamber 9a, and the arrow 5 It is also possible to generate an urging force in the direction of the other opening 3b opposite to B. That is, the axial movement of the gas distribution nozzle 3 is enabled by these differential pressures. The configuration for generating the differential pressure in the first pressure adjusting chamber 9a and the second pressure adjusting chamber 9b exemplified in the pressure adjusting path 17 described above constitutes the differential pressure generating means 15 in the present invention.

  The gas distribution nozzle 3 moves in the front-rear direction of the arrow B by the generation of the differential pressure described above. An upper surface 10a on which one opening 3a in the gas supply / discharge mechanism 10 is disposed is positioned on an upper surface of a mounting table described later, and a pod is mounted on the upper surface. In addition, a valve for introducing or discharging gas is disposed on a surface facing the mounting table which is the lower surface of the pod. Due to the movement in the direction of arrow B, one opening 3a of the gas flow nozzle 3 protrudes from the upper surface 10a and comes into contact with a valve in the pod. As a result, gas can be introduced into or discharged from the pod through the gas flow nozzle 3 and the valve. Further, by driving the gas flow nozzle 3 in the direction opposite to the arrow B by the differential pressure, the above-described gas introduction or discharge operation is completed, and the so-called atmosphere replacement operation to a predetermined atmosphere inside the pod is completed. I can do it.

  Since the gas circulation chamber 11 must always be connected to the gas circulation nozzle 3, the other opening 3 b is opened inside the gas circulation chamber 11 regardless of the driving of the gas circulation nozzle 3 in the direction of arrow B. It is necessary to do. Therefore, the gas circulation chamber 11 needs to have a thickness that is greater than or equal to the driving range of the gas circulation nozzle 3 or a size that includes the moving range of the other opening 3b in the axial direction described above. The above-described configuration is the main configuration of the gas supply / exhaust mechanism 10 described with reference to a simplified diagram. In practice, the pressure in each pressure adjustment chamber can be maintained. As described above, there are additional structures such as various seal members arranged at important points.

(Example)
Next, a specific embodiment of the internal configuration of the gas supply / discharge mechanism 10 will be described with reference to FIG. In the following embodiments, the same reference numerals are used to denote configurations that exhibit the same functions and effects as those described in FIG. 1, and detailed descriptions thereof are omitted. In the gas supply / discharge mechanism 10 of the present embodiment, a plurality of seal members 16 a, 16 b, 16 c are arranged between the gas flow nozzle 3 and the housing part 7. The first seal member 16 a is disposed on the gas flow nozzle 3 on the side of the opening 3 b other than the flange portion 5. The first seal member 16 a is airtight between the gas flow chamber 11 and the first pressure adjustment chamber 9 a, The sliding with respect to the housing part 7 is ensured. The second seal member 16b is disposed between the outer peripheral surface of the flange portion 5 and the inner peripheral surface of the pressure chamber 9, and separates the first pressure adjustment chamber 9a and the second pressure adjustment chamber 9b. The pressure difference between these chambers can be easily generated. The third seal member 16c is disposed on the side of the opening 3a with respect to the flange 5 in the gas flow nozzle 3, and is hermetically sealed between the second pressure adjusting chamber 9b and the external space, and the housing portion of the gas flow nozzle 3. 7 to ensure sliding.

  The pressure adjusting path 17 is connected to the second pressure adjusting chamber 9b. The pressure adjusting path 17 is connected to the vacuum system 17a and the pressurized air supply system 17b, and the pressure in the second pressure adjusting chamber 9b can be increased or decreased by operating an associated valve. The configuration for generating the differential pressure in the first and second pressure adjusting chambers 9 a and 9 b exemplified in the pressure adjusting path 17 constitutes the differential pressure generating means 15. In addition, a fourth seal member 16d is disposed around one opening 3a, and space separation from the external space when the first opening 3a is connected to a valve on the pod side (not shown) This is done by the four seal members 16d.

By adopting the form described above, the chamber whose internal pressure is higher than the so-called atmospheric pressure is only the second pressure regulating chamber 9b. Between the second pressure regulating chamber 9b and the gas circulation chamber 11, the first pressure regulating chamber 9a is disposed. When the gas supply / discharge mechanism 10 is used as an inert gas supply path exemplified by nitrogen or the like in the pod, a high purity and dry inert gas is supplied to the gas circulation chamber 11. By disposing the first pressure adjusting chamber 9a having an internal pressure corresponding to the atmospheric pressure between the pressurized second pressure adjusting chamber 9b and the gas circulation chamber 11, the gas is discharged from the second pressure adjusting chamber 9b. A secondary effect of suppressing gas leakage to the circulation chamber 11 is obtained.

  However, the aspect of the differential pressure generating means 15 is not limited to this embodiment. For example, in order to make the movement of the gas flow valve 3 only in the second pressure regulation chamber 9b easier, the first pressure regulation chamber 9a and the external space are communicated with each other in the first pressure regulation chamber 9a. An air vent 9c (see FIG. 2) for eliminating pressure fluctuations may be provided. It is also possible to connect the pressure adjusting path 17 described above only to the first pressure adjusting chamber 9a. Alternatively, the pressure adjusting path 17 may be connected to both the first pressure adjusting chamber 9a and the second pressure adjusting chamber 9b to individually control the internal pressures. With these configurations, a large differential pressure can be obtained, and the effect of quickly and reliably moving the gas flow valve 3 can be obtained. Further, in the case where the pressure adjusting path 17 is connected to only one pressure adjusting chamber, if it is difficult to secure a sufficient moving speed of the gas flow valve 3 with only the differential pressure, the urging force is assisted in one chamber. An elastic member exemplified by a spring or the like may be disposed as the biasing force assisting means. For example, when the gas flow valve 3 is moved only in the second pressure adjustment chamber 9b, the gas flow valve 3 is placed in the direction of arrow B inside the first pressure adjustment chamber 9a as illustrated in FIG. It is preferable to dispose an elastic member 19 that biases the spring.

  Next, the load port apparatus 100 provided with the gas supply / discharge mechanism 10 described above will be described. FIG. 3 is a diagram illustrating a main configuration of the load port apparatus 100 having a plurality of the gas supply / discharge mechanisms 10 illustrated in FIG. 2 and a state where the pod 120 mounted on the mounting table is viewed from the side. The load port device 100 includes a base plate 101, a door 105, a mounting table 109, and a gas supply / discharge mechanism 10. The base plate 101 has an opening 102 provided so as to separate a minute space whose cleanliness is controlled from the surrounding environment and to face the opening of the pod 120. A pod 120 is mounted on the mounting table 109, and the opening of the pod 120 that is closed by a lid (not shown) is opposed to the opening 102 in the minute space.

  The door 105 closes the opening 102 during standby to make the minute space a closed space, and holds and removes the lid of the pod 120 while the pod 120 is mounted on the mounting table 109 to open the pod 120. Let The above-described valve 120a is provided on the lower surface of the pod 120, and it is possible to supply or discharge a gas such as an inert gas into the pod 120 through the gas supply / discharge mechanism 10 and the valve 120a. In the embodiment shown in FIG. 3, the inert gas is supplied into the pod 120 from the gas supply / discharge mechanism 10 disposed on the opening 102 side, and the other gas supply / discharge memory 10 causes an excess from the pod 120. The internal atmosphere is discharged. By performing this operation for an appropriate time, the atmosphere in the pod 120 can be replaced with a high-purity dry inert gas, and the partial pressure of the oxidizing gas in the atmosphere can be lowered from a desired value.

  Here, in the same manner as in FIG. 3, a case where a conventionally used gas supply / discharge mechanism 130 is used is shown in FIG. 4 as a comparative example. In the conventional load port device shown in FIG. 4, since there is no configuration different from the present invention except for the gas supply / discharge mechanism 130, the description of other configurations is omitted by using the same reference numerals. As understood from the figure, in the conventional gas supply / discharge mechanism 130, a cylinder 131 or an inert gas supply pipe 131 exists below. For this reason, compared with the case where the gas supply / exhaust mechanism 10 of this invention is used, the space which the structure arrange | positioned in the mounting base 109 or its lower part occupies becomes large.

  As described above, in the current semiconductor manufacturing process, the so-called cleanliness of the space in which the pod itself is transported does not require the cleanliness of the minute space. However, the space below the mounting table 109 where the drive mechanism of the door 105 exists also partially communicates with the space so that the arm supporting the door 105 protrudes into the minute space. For this reason, the degree of cleanliness above a certain level is always required for the lower space of the mounting table 109. Therefore, it is desirable to reduce as much as possible the configuration that requires an occupied space such as the conventional configuration that is desired to be avoided when maintaining the cleanliness. As shown in FIG. 3, with the gas supply / exhaust mechanism 10 according to the present invention, this occupied space can be kept small, and piping and the like can be reduced, so that the cleanliness of the space can be easily maintained.

  Here, the actual operation of the gas flow valve 3 will be described with reference to the drawings. FIGS. 5A to 5C show the configuration related to the gas supply / discharge mechanism 10 in the load port apparatus 100 in the same manner as in FIG. 2, and show the respective stages during operation. . FIG. 5 (a) shows the gas supply / discharge mechanism 10 in a standby state, in which the inside of the second pressure adjustment chamber 9b is pressurized by a pressurized air supply system 17b, and thereby the gas flow nozzle 3 is moved downward. Stopped at the standby position. On the other hand, a pod (not shown) is mounted on a mounting table, and the gas flow nozzle 3 in a standby state and the valve 120a of the pod are in a predetermined positional relationship shown in the drawing.

  After confirming that the predetermined positional relationship exists, the path of the pressurized air supply system 17b is closed and the vacuum system 17a is opened. As a result, the inside of the second pressure regulating chamber 9b is depressurized, and the gas distribution nozzle 3 is moved upward by the pressure difference from the inside of the first pressure regulating chamber 9a maintained at atmospheric pressure. The upward movement stops when one opening 3a of the gas distribution nozzle 3 is connected to the valve 120a and gas can be supplied and exhausted through the valve 120a. This state is shown in FIG. Subsequently, the supply of the inert gas to the gas circulation chamber 11 is started via the gas supply / discharge pipe 13 while maintaining the state of the pressurized air supply system 17b and the vacuum system 17a. The inert gas flows into the pod through the gas circulation chamber 11, the path from the other opening 3b of the gas circulation nozzle 3 to the one opening 3a, and the valve 120a. By the above operation, the supply of the inert gas into the pod is executed.

  The same operation is also performed in the gas supply / discharge mechanism 10 for exhausting the internal atmosphere, so that the atmosphere in the pod that has become excessive due to the supply of the inert gas is transferred from the valve 120 a and one opening 3 a of the gas distribution nozzle 3 to the other. The gas is discharged from the gas supply / discharge pipe 13 through the path to the opening 3 b and the path of the gas circulation chamber 11. After the atmosphere replacement in the pod is completed, the gas flow nozzle 3 is moved downward by the operation opposite to the operation described here, and returned to the standby position shown in FIG. By arranging the downsized gas supply / discharge mechanism 10 having the above configuration in the load port device 100, the configuration disposed in the lower space of the mounting table 109 is reduced, and the cleanliness of the space can be maintained and managed more. It will be easy.

  As described above, the present invention relates to a load lock chamber suitably used for a semiconductor processing apparatus. However, the applicability of the present invention is not limited to the processing apparatus. For example, for a so-called load lock chamber used in various processing apparatuses that perform various processes in accordance with semiconductors, such as a processing apparatus that handles a panel of a liquid crystal display. Is applicable. Therefore, it is preferable that the wafer in the above-described embodiment is interpreted as a workpiece, the pod accommodates various workpieces, and the semiconductor processing apparatus is treated as a processing apparatus for processing the workpiece.

3: Gas distribution nozzle, 3a: One opening, 3b: Other opening, 5: Gutter part, 7: Housing part, 9: Pressure chamber, 9a: First pressure regulation chamber, 9b: Second pressure regulation chamber 9c: air vent hole, 10: gas supply / discharge mechanism, 10a: upper surface, 11: gas distribution chamber, 13: gas supply / discharge pipe, 15: differential pressure generating means, 16a: first seal member, 16b: second Seal member, 16c: third seal member, 17: pressure adjusting path, 17a: vacuum system 17a, 17b: pressurized air supply system, 19: elastic member, 100: load port device, 101: base plate, 102: opening , 105: door, 109: mounting table, 120: pod, 120a: valve, 130: gas supply / discharge mechanism, 131: piping

Claims (10)

A load port device that opens and closes a lid of a pod so that the object to be processed can be inserted into and removed from the pod, and the object to be processed can be transported to the processing apparatus along with the processing object processing apparatus. Because
A mounting table on which the pod is mounted;
A cylindrical gas flow nozzle having a flange and one opening located on the mounting table,
A housing portion having a pressure chamber through which the gas flow nozzle penetrates in the axial direction and separated into a first pressure adjustment chamber and a second pressure adjustment chamber by the flange portion;
A gas circulation chamber in which the other opening of the gas circulation nozzle is opened inside, and the positional relationship with the pressure chamber is fixed;
Differential pressure generating means for generating a differential pressure between the first pressure adjusting chamber and the second pressure adjusting chamber and moving the gas flow nozzle in the axial direction by applying the differential pressure to the flange portion. and, the possess,
It said gas flow chamber, load port apparatus characterized by have a size including the movement range of the other opening when the gas flow nozzle by the differential pressure is moved in the axial direction.
A load port device that opens and closes a lid of a pod so that the object to be processed can be inserted into and removed from the pod, and the object to be processed can be transported to the processing apparatus along with the processing object processing apparatus. Because
A mounting table on which the pod is mounted;
A cylindrical gas flow nozzle having a flange and one opening located on the mounting table,
A housing portion having a pressure chamber through which the gas flow nozzle penetrates in the axial direction and separated into a first pressure adjustment chamber and a second pressure adjustment chamber by the flange portion;
A gas circulation chamber in which the other opening of the gas circulation nozzle is opened inside, and the positional relationship with the pressure chamber is fixed;
Differential pressure generating means for generating a differential pressure between the first pressure adjusting chamber and the second pressure adjusting chamber and moving the gas flow nozzle in the axial direction by applying the differential pressure to the flange portion. And having
The load port device , wherein the differential pressure generating means is connected only to the second pressure regulating chamber .
The load port device according to claim 2, wherein the first pressure regulation chamber has a hole that communicates with an external space.
A load port device that opens and closes a lid of a pod so that the object to be processed can be inserted into and removed from the pod, and the object to be processed can be transported to the processing apparatus along with the processing object processing apparatus. Because
A mounting table on which the pod is mounted;
A cylindrical gas flow nozzle having a flange and one opening located on the mounting table,
A housing portion having a pressure chamber through which the gas flow nozzle penetrates in the axial direction and separated into a first pressure adjustment chamber and a second pressure adjustment chamber by the flange portion;
A gas circulation chamber in which the other opening of the gas circulation nozzle is opened inside, and the positional relationship with the pressure chamber is fixed;
Differential pressure generating means for generating a differential pressure between the first pressure adjusting chamber and the second pressure adjusting chamber and moving the gas flow nozzle in the axial direction by applying the differential pressure to the flange portion. And having
A load port device comprising biasing force assisting means arranged in one chamber of the first pressure regulation chamber or the second pressure regulation chamber to apply a biasing force in the axial direction to the flange portion. .
The differential pressure generating means adjusts the internal pressure by supplying and discharging gas to and from the second pressure adjusting chamber disposed on the one opening side in the axial direction. The load port device according to any one of claims 1 to 4, further comprising means.
A mounting table on which the pod is mounted;
A cylindrical gas flow nozzle having a flange and one opening located on the mounting table,
A housing portion having a pressure chamber through which the gas flow nozzle penetrates in the axial direction and separated into a first pressure adjustment chamber and a second pressure adjustment chamber by the flange portion;
A gas circulation chamber in which the other opening of the gas circulation nozzle is opened inside, and the positional relationship with the pressure chamber is fixed;
Differential pressure generating means for generating a differential pressure between the first pressure adjusting chamber and the second pressure adjusting chamber and moving the gas flow nozzle in the axial direction by applying the differential pressure to the flange portion. And having
The gas supply / exhaust mechanism, wherein the gas flow chamber has a size including a moving range of the other opening when the gas flow nozzle moves in the axial direction due to the differential pressure.
A mounting table on which the pod is mounted;
A cylindrical gas flow nozzle having a flange and one opening located on the mounting table,
A housing portion having a pressure chamber through which the gas flow nozzle penetrates in the axial direction and separated into a first pressure adjustment chamber and a second pressure adjustment chamber by the flange portion;
A gas circulation chamber in which the other opening of the gas circulation nozzle is opened inside, and the positional relationship with the pressure chamber is fixed;
Differential pressure generating means for generating a differential pressure between the first pressure adjusting chamber and the second pressure adjusting chamber and moving the gas flow nozzle in the axial direction by applying the differential pressure to the flange portion. And having
The gas supply / exhaust mechanism, wherein the differential pressure generating means is connected only to the second pressure regulating chamber.
The gas supply / exhaust mechanism according to claim 7, wherein the first pressure regulation chamber has a vent hole communicating with an external space.
A mounting table on which the pod is mounted;
A cylindrical gas flow nozzle having a flange and one opening located on the mounting table,
A housing portion having a pressure chamber through which the gas flow nozzle penetrates in the axial direction and separated into a first pressure adjustment chamber and a second pressure adjustment chamber by the flange portion;
A gas circulation chamber in which the other opening of the gas circulation nozzle is opened inside, and the positional relationship with the pressure chamber is fixed;
Differential pressure generating means for generating a differential pressure between the first pressure adjusting chamber and the second pressure adjusting chamber and moving the gas flow nozzle in the axial direction by applying the differential pressure to the flange portion. And having
A gas supply / discharge mechanism comprising biasing force assisting means arranged in one chamber of the first pressure regulation chamber or the second pressure regulation chamber and applying a biasing force in the axial direction to the flange portion
The differential pressure generating means adjusts the internal pressure by supplying and discharging gas to and from the second pressure adjusting chamber disposed on the one opening side in the axial direction. The gas supply / discharge mechanism according to any one of claims 6 to 9, further comprising means.

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