JP2000329254A - Valve device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve device used in a connection portion between a vacuum vessel and an exhaust system in a semiconductor manufacturing device or the like, which effectively adheres a product reacted in a process in the valve device. The present invention provides a valve device which can be prevented. SOLUTION: A valve seat provided on one side in a valve box,
A valve body opposed to the valve seat, supported by a valve opening / closing shaft and arranged so as to be detachable from the valve seat; a valve body surrounding the shaft; A bellows respectively fixed to an end plate of a valve box arranged opposite to the valve seat, wherein a heater is installed outside and inside the bellows, respectively,
A heater installed outside the bellows is a cylindrical heater surrounding the bellows, one end of which is attached to the end plate, and the other end is open toward the valve seat, By the valve device characterized in that the opening of the cylindrical heater is closed by the valve body during the opening operation of the valve,
The problem has been solved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve device used in an industrial field utilizing a vacuum such as a semiconductor manufacturing apparatus, and more particularly to a valve device used for a connection between a vacuum vessel and an exhaust system. And a valve device capable of effectively preventing a product reacted in a process step from adhering to the inside of the valve device.

[0002]

2. Description of the Related Art Conventionally, a valve device used for connecting a vacuum vessel of a semiconductor manufacturing apparatus or the like to an exhaust system, the valve device including a valve seat and a valve body opposed to the valve seat, As an example of the case where the valve device itself is heated, one having a configuration as shown in FIG. 2 is known. That is, the valve seat 1 is provided with the valve seat 2, and the bonnet flange 3a and the pipe connection flanges 4a and 4b are fixed. A valve body 6 equipped with a main gasket 5 is arranged facing the valve seat 2, and the valve body 6 is air-tightly joined to a peripheral edge of one end of a bellows 7. On the other hand, the peripheral edge of the other end of the bellows 7 is air-tightly joined to an end plate 8 of the valve box 1 arranged to face the valve seat 2, and the end plate 8 is connected to the bonnet flange 3 a by a gasket 9.
It is mounted airtight. For this reason, the inner and outer spaces of the bellows 7 are partitioned, but the communication groove 22 is provided in the bonnet flange 3b so that the inner space of the bellows 7 is always at atmospheric pressure.

The bellows 7 is provided with a bellows guide 10, which suppresses deformation of the bellows 7 in directions other than the expansion and contraction direction, and improves the durability of the bellows 7.

A cylinder 11 for opening and closing the valve is fixed to a bonnet flange 3b, and a shaft 13 for moving the valve 6 is connected to a cylinder rod 12. The shaft 13
Is connected to the valve body 6, the shaft 13 is moved in the direction of the arrow 16 by the cylinder 11, whereby the valve body 6 is separated from and brought into contact with the valve seat 2, and the valve is opened and closed. FIG. 2 shows a state in which a valve is closed in a conventional valve device.

A heater 20 is provided on the outer surface of the valve box 1 of the valve device so that the entire valve device can be heated. Further, as shown in FIG. 3, a sheath heater 2 is provided inside the bellows 7 so that the heater is not disconnected even when the valve device opens and closes.
An example in which 1 is attached in a spiral shape is also known.

[0006]

SUMMARY OF THE INVENTION A CVD (Chemica) for semiconductor production equipped with the conventional valve device as described above.
In a vacuum exhaust system such as an l-vapor-deposition device, a method of heating the exhaust system is used to achieve high vacuum, in order to forcibly exhaust the gas adsorbed and occluded on the inner surface exposed to the reactive gas. ing.

In the case where the gas is exhausted while introducing a reaction gas for film formation, in a semiconductor manufacturing apparatus, a product reacted in a process may adhere to the inside of the valve device. When this product adheres to the inner surface of the valve device and to the bellows, particularly when the bellows is in a contracted state, there is a problem that the adhered product becomes a load and shortens the life of the bellows. There is also a problem that a process condition cannot be reproduced due to the decomposition of the adhered product. Further, when the product adheres to the main gasket, there is a problem that the vacuum sealing cannot be performed even when the valve device is closed.

As a measure for preventing the adhesion of the product, a method of heating the valve device to a temperature higher than the vapor pressure temperature of the product is used. In this method of heating the valve device, a heater is arranged on the atmospheric pressure side, which is outside the valve box, to perform heating.

However, in this method, when the space inside the valve device is in a vacuum state or when the valve device is in an open state, the bellows, the valve body, and the main gasket disposed inside the valve device are mainly thermally conductive. Because of heating, it took a long time for the temperature to rise.

Further, in the conventional method of heating from the outside of the valve device on the atmospheric pressure side, a temperature difference occurs between the valve box and the components (bellows, valve body, main gasket) disposed inside the valve device. Even if the box is heated to the allowable upper limit temperature, there is a problem that the components arranged inside the valve device are not heated to the target temperature.

On the other hand, recently, as a countermeasure, a method of heating a bellows by forming a sheath heater in a spiral shape like a coil spring on the atmosphere side inside the bellows has been used (FIG. 3). However, in this structure, the sheath heater also expands and contracts with the opening and closing of the valve, so that there is a problem in the durability and reliability of the heater. Further, if the bellows guide is provided around the shaft of the valve opening / closing shaft in order to improve the durability of the bellows, there is a problem that the position of the sheath heater becomes structurally complicated.

[0012]

According to the present invention, there is provided a bellows which surrounds a shaft for opening and closing a valve, and is separated from the valve seat by being opposed to a valve seat provided on one side of a valve box. A peripheral edge of one end of the valve body disposed so as to be in contact with the periphery of a bellows having a peripheral edge of the other end fixed to an end plate of a valve box disposed opposite to the valve seat. Is attached to the end plate, the other end is arranged a cylindrical heater opening toward the valve seat direction, at the time of opening the valve, the opening of the cylindrical heater is closed by the valve body, This problem has been solved by sealing the bellows surrounding the valve opening / closing shaft with the cylindrical heater and the valve body so that the bellows is not exposed to the reactive gas.

That is, the present invention provides a valve seat provided on one side in a valve box, and is disposed opposite to the valve seat and supported by a valve opening / closing shaft so as to be detachable from the valve seat. And a peripheral edge at one end thereof is fixed to an end plate of a valve box disposed at a position opposite to the valve seat. The bellows or the partition made of a flexible member, and a heater is installed outside and inside the partition made of the bellows or the flexible member, respectively. A heater installed outside the partition surrounds the partition made of the bellows or the flexible member, a peripheral edge of one end is attached to the end plate, and the other end is opened toward the valve seat. It is a cylindrical heater, and when the valve is opened, A valve device which is characterized in that the opening of the tubular heater is blocked by the valve body.

With the valve device constructed as described above, in the valve device of the present invention, the partition made of a bellows or a flexible member surrounding the valve opening / closing shaft can be protected from outside the valve device. However, since the heating is performed by the cylindrical heater inside the valve device and surrounding the bellows and the partition wall, the temperature can be raised in a shorter time. Further, at the time of opening the valve, a partition formed of a bellows or a flexible member surrounding the shaft for opening and closing the valve is sealed with a cylindrical heater and a valve body, and the bellows and the partition are exposed to the reactive gas. Is gone. Furthermore, at the time of opening the valve, the valve element and the main gasket attached to the distal end side (valve seat side) of the valve element are directly heated by the cylindrical heater, so that the temperature can be raised in a short time. .

As a result of the above construction, when the valve is opened, that is, the introduced reaction gas is exhausted, the reaction product is most likely to be generated inside the valve device, that is, the outer surface of the partition made of a bellows or a flexible member. And, when it is easily attached to the inner surface of the valve box, especially, the outer surfaces of the bellows and the partition are covered and hidden, and the process gas does not easily enter the side where the cylindrical heater and the valve body are sealed and the partition has the side. Under such a condition, the outer surfaces of the bellows and the partition wall and the inner surface of the valve box are heated. Therefore, the reaction product hardly adheres to the inside of the valve device, particularly to the outer surface of the partition wall made of the bellows or the flexible member.

In addition, since the inner surface of the valve box can be directly heated by using the cylindrical heater, the heater outside the valve device can be omitted, so that there is an advantage that the valve device can be inexpensively manufactured.

Further, the present invention provides the valve device having the above-mentioned construction, wherein the heater installed inside the bellows or the partition wall made of a flexible member is attached to a shaft for opening and closing the valve, preferably, the valve. Attaching the opening / closing shaft near the joint with the valve body eliminates the need for the heater that heats the bellows and partition from inside to open and close the valve when opening and closing the valve, ensuring the durability and reliability of the heater It was made possible. Even when the heater is attached to the valve opening / closing shaft in this manner, in the valve device of the present invention, the valve opening / closing shaft is a hollow shaft, and a lead for supplying power to the heater from outside the valve box. Since the wire is passed through the hollow shaft, the power supply lead wire of the heater is not blocked by the bellows guide.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a sectional view of an embodiment of the valve device according to the present invention, showing a state where the valve is in an open state.

A valve seat 1 constituting a valve device is provided with a valve seat 2, and a bonnet flange 3a and pipe connection flanges 4a, 4b are fixedly attached thereto.

A valve body 6 equipped with a main gasket 5 is arranged facing the valve seat 2, and the valve body 6 is air-tightly joined to a peripheral edge of one end of a bellows 7.

On the other hand, the periphery of the other end of the bellows 7 is
Is air-tightly joined to the end plate 8 of the valve box 1 which is arranged to face. The end plate 8 is hermetically attached to the bonnet flange 3a by a gasket 9. Thus, as shown in FIG. 1, the inner and outer spaces of the bellows 7 are partitioned, but a communication groove 22 is provided in the bonnet flange 3 b so that the inner space of the bellows 7 is always at atmospheric pressure.

The bellows 7 has a bellows guide 1
The bellows guide 10 suppresses bending of the bellows 7 in directions other than the expansion and contraction direction, thereby improving the durability of the bellows 7 against expansion and contraction.

On the other hand, the cylinder 11 is fixed to the bonnet flange 3b, and the cylinder rod 12 of the cylinder 11
Is connected to a hollow shaft 13 for moving the valve body 6 to open and close the valve. That is, the hollow shaft 13 is moved by the cylinder 11 to the arrow 16 or 16.
It is configured to move upward or downward in the direction of “a” and to be separated from and brought into contact with the valve seat 2.

The hollow shaft 13 is connected to the valve body 6 and the shaft gasket 14 with a nut 15 so as to be airtight.

A heater 17 is mounted on the hollow shaft 13, and a lead wire 18 for supplying power to the heater 17 is connected to the valve box 1 through a through hole 19 of the hollow shaft 13.
Extends outside. With this heater 17, the bellows 7, the valve body 6, and the main gasket 5 can be heated by the heater 17 alone.

The heater 17 attached to the hollow shaft 13 covers the entire outer periphery of the hollow shaft 13 so as to face the inner peripheral surface of the bellows 7 in order to efficiently heat the bellows 7 surrounding the hollow shaft 13. Preferably, the hollow shaft 13 is attached as shown in FIG. 1 so that the valve body 6 can be directly heated and the heating efficiency for the main gasket 5 can be improved.
It is preferable to attach it near the joint with the valve body 6.

In the valve device according to the present invention, a cylindrical heater 23 is provided on the end plate 8.
Power is supplied by the heater power supply lead wire 24. With this cylindrical heater 23, the entire outer peripheral surface of the bellows 7 can be heated from a position close to the bellows 7, and the entire inner peripheral surface of the valve box 1 can also be heated from a position close to this. .

At the time of the opening operation of the valve body 6 shown in FIG.
The valve element 6 is engaged with an opening on the side of the cylindrical heater 23 facing the valve seat 2 by a sealing gasket 25 so as to eliminate the gap therebetween, and the hollow shaft 13 and the bellows 7 surrounding the hollow shaft 13 are provided. , And is built in the cylindrical heater 23 and the valve body 6.

According to the valve device of the present invention, since the inner peripheral surface of the valve box 1 can be directly heated by the cylindrical heater 23, it can be omitted. A configuration in which the outer surface of the first unit 1 is heated by the heater 20 may be employed.

In the valve device of this embodiment, the hollow shaft 13 is raised as shown by the arrow 16 and the valve body 6 is moved to the valve seat 2.
When the valve is separated from the heater 23 and is brought into contact with the lower peripheral edge of the heater 23 (FIG. 1, at the time of the opening operation of the valve element 6), the entire bellows 7 can be hermetically sealed. be able to.

When power is supplied to the lead wire 18, the heater 1
7, the bellows 7, the valve body 6, and the main gasket 5 can be heated. However, since the heater 17 is mounted on the hollow shaft 13, the hollow shaft is
Even if the heater 17 moves in the directions 6 and 16a, the heater 17 does not need to perform the expansion and contraction movement, and there is no possibility that the durability of the heater 17 is adversely affected.

[0032]

According to the present invention, in the state where the valve body is in the opening operation, that is, when the introduced reactive process gas is exhausted, the reaction product is most likely to adhere to the inside of the valve device. The valve element covers the opening of the cylindrical heater arranged on the outer periphery of the bellows.
Since the valve body support portion including the bellows is built in while being sealed by the valve body and the cylindrical heater, the outer periphery of the bellows is not directly exposed to the flow of the reactive process gas. Product adhesion to the outer peripheral portion of the bellows and the like is greatly reduced.

The valve opening / closing shaft located inside the bellows in the valve device is a hollow shaft, a heater is fixed to the hollow shaft, and a lead wire for supplying power to the heater passes through the hollow shaft. Therefore, even when the hollow shaft is moved so as to move the valve body toward and away from the valve seat, the heater does not need to perform the expansion and contraction movement.

In addition, the internal structure of the valve device such as the bellows, the valve body, and the main gasket is directly controlled by the heater inside the bellows fixed to the hollow shaft and the cylindrical heater arranged on the outer periphery of the bellows. Can be heated in a short period of time, so that even if a product due to the reaction gas adheres to the outer peripheral surface of the bellows, etc., the desorption of the product by the reaction gas and forced evacuation are extremely effective. It can be carried out.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view in which a part of an embodiment of the present invention is omitted.

FIG. 2 is a longitudinal sectional front view showing an example of a conventional valve device.

FIG. 3 is a longitudinal sectional front view showing a part of another conventional valve device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Valve box 2 Valve seat 3a, 3b Bonnet flange 4a, 4b Piping connection flange 5 Main gasket 6 Valve 7 Bellows 8 End plate 9 Gasket 10 Bellows guide 11 Cylinder 12 Cylinder rod 13 Hollow shaft 14 Shaft gasket 15 Nut 17 Heater 18 Heater Lead wire 19 Through hole 20 Heater 22 Communication groove 23 Cylindrical heater 24 Heater lead wire 25 Gasket for sealing

Claims (2)

[Claims] A valve seat provided on one side of the valve box;
A valve body opposed to the valve seat, supported by a valve opening / closing shaft and arranged so as to be detachable from the valve seat, and surrounding the valve opening / closing shaft; The other end is constituted by a bellows or a partition made of a flexible member fixed to an end plate of a valve box arranged opposite to the valve seat, and made of the bellows or the flexible member. In the valve device in which a heater is installed outside and inside the partition, respectively, the heater installed outside the bellows or the partition made of a flexible member surrounds the partition made of the bellows or the flexible member. A cylindrical heater having one end attached to the end plate and the other end opened toward the valve seat, and the opening of the cylindrical heater is closed by the valve body when the valve is opened. A valve device characterized by being sealed off. 2. A valve opening / closing shaft is a hollow shaft, and a heater installed inside a partition made of the bellows or a flexible member is attached to the hollow shaft. The valve device according to claim 1, wherein a lead wire for supplying electric power to the heater from outside penetrates through the hollow shaft.