JP2003074744A - Vacuum valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum valve structured to reduce dust produced from a vacuum seal and to suppress the scatter of dust, and its operating method. SOLUTION: This vacuum valve is provided with a first valve element 3 of plate shape controlled to move following opening/closing operation; a second valve element 4 disposed between the first valve element 3 and a valve seat 9 and driven interlocked with the first valve element 3; a first seal 5 provided on the second valve element 4 side face of the first valve element 3; a second seal 6 provided on the valve seat 9 side face of the second valve element 4; an adjusting means for adjusting the motion of the second valve element 4 to the first valve element 3 so that the first valve element 3 is released from the second valve element 4 in the state of maintaining the contact state of the valve seat 9 and second valve element 4 in a first stage when the first valve element 3 is operated to open and to release the second valve element 4 from the valve seat 9 in a following second stage; and a ventilating part 4b provided at the center part of the second valve element 4. It is preferable to provide the ventilating part 4b with a dust filter 4c.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a vacuum valve used in a semiconductor manufacturing facility or the like. Specifically, the present invention relates to a vacuum valve having a structure that suppresses the generation of dust.

[0002]

2. Description of the Related Art For example, in a semiconductor manufacturing facility, the inside of a vacuum chamber is kept in vacuum to perform a surface treatment, etching, etc. on a wafer. The inside of the vacuum chamber is evacuated using a vacuum pump, and the vacuum valve is closed to maintain the vacuum. When a wafer is processed, impurities and the like float in the vacuum chamber as dust or adhere to the wall surface, significantly lowering the yield of semiconductor products. It is necessary to return the vacuum chamber to the atmosphere and perform dust removal maintenance.

FIG. 3 shows the structure of the vacuum valve disclosed in Japanese Patent Laid-Open No. 10822/1989. In this conventional example, side walls 11a and 11b of a box-shaped valve box 11 are provided with openings 12a and 12b communicating with a vacuum chamber 10 and a vacuum pump (not shown), respectively, and a valve seat 13 is provided in the opening 12a. It is installed. Valve seat 1
A seal is provided on the end face of the valve body 14 in the valve box 11 seated on
4a is provided, and one end of the valve rod 15 is attached to the other end. A cylindrical first bearing support 16 inserted into the valve box 11 is attached to the valve box 11, and the first bearing support 16 has a first bearing support member 16 at one end in the valve box 11.
Spherical bearing 17 is provided, and the first spherical bearing 17 pivotally supports a middle portion of the valve rod 15. First spherical bearing 17
A valve rod driving cylinder 19 is attached to the end of the valve rod 15 protruding from the valve box 11 via a second spherical bearing 18. A bellows fixing plate 20 is fixed to a portion of the valve rod 15 inside the valve box 11, and a first spherical bearing 1 is provided between the bellows fixing plate 20 and the wall surface of the valve box 11.
A flexible bellows 21 is attached so as to cover the periphery of 7.

In the conventional vacuum valve having such a structure, when the valve is opened, the valve rod driving cylinder 19 is retracted, and the other end of the valve rod 15 is inserted through the second spherical bearing 18 to cause a Driven in the direction, the tip of the valve rod 15 is driven in the c direction with the first spherical bearing 17 as a fulcrum, the space between the seal 14a on the end face of the valve body 14 and the valve seat 13 is opened, and the vacuum chamber 10 The inside and the inside of the valve box 11 are in communication with each other through the opening 12a. On the contrary, when closing the valve, when the valve rod driving cylinder 19 is moved forward, the other end of the valve rod 15 moves to the second position.
Driven in the direction of b in the drawing through the spherical bearing 18 of
With the spherical bearing 17 as a fulcrum, the tip of the valve rod 15 is driven in the d direction, and the seal 14a and the valve seat 13 on the end face of the valve body 14 are driven.
And the inside of the vacuum chamber 10 and the inside of the valve box 11 are closed.

In this prior art example, when the valve body 14 is opened and closed, the bellows 21 is kept in contact with the atmosphere inside the valve box 11 and the first
Since it is isolated from the spherical bearing 17 of the first spherical bearing 17, the dust generated by the wear of the first spherical bearing 17 is not transmitted to the atmosphere in the valve box 11, so that the dust is prevented from entering the vacuum chamber 10. That is.

[0006]

As described above, in the conventional example, the bellows 21 prevents dust generation due to wear of the valve rod 15 and the first spherical bearing 17. However, when the vacuum valve is opened and closed, the seal 14a is repeatedly compressed and deteriorated, and dust is easily generated due to friction with the valve seat 13.
The dust is scattered due to the pressure difference between the inside of the valve box 11 and the inside of the vacuum chamber 10 when the vacuum valve is opened. The bellows 21 of the conventional example has no effect on such dust generation and scattering from the seal 14a.

In order to solve such a problem, in the case of the conventional structure, the material of the seal 14a should be improved to a material which is less likely to be worn or deteriorated, or the seal 14a should be replaced in a short period of time. However, this increases the material cost and increases the man-hours for maintenance and inspection.

[0008] Therefore, the problem to be solved by the present invention is
It is intended to provide a vacuum valve having a structure capable of reducing dust generation from a seal and further suppressing dust scattering.

[0009]

In order to solve the above-mentioned problems, a vacuum valve according to the present invention includes a plate-shaped first valve body whose movement is controlled in accordance with an opening / closing operation, and the first valve body and the valve. A second valve body which is arranged between the seat and a second valve body which is driven in conjunction with the first valve body, and which is attached to a contact portion of the first valve body with the second valve body. No. 1 seal, a second seal attached to a contact portion of the second valve body with the valve seat, and when the first valve body is operated to open, in the first stage, the valve seat So that the first valve body is released from the second valve body while maintaining the contact state between the first valve body and the second valve body in the second stage following the first stage. Adjusting means for adjusting the movement of the second valve body with respect to the first valve body so as to be released from the seat, and the inside of the second seal in the second valve body It is obtained by a provided ventilation unit.

In the present invention, when the vacuum valve is opened,
First, the first valve body separates from the second valve body, and the second valve body is closed. As a result, outside air is introduced into the vacuum chamber from the ventilation portion of the second valve body via the valve seat. The ventilation portion absorbs a sudden pressure change based on the pressure difference between the vacuum chamber and the outside when the vacuum valve is opened. Therefore, the dust is prevented from being rolled up. When the vacuum valve is further opened, the second valve body is also released from the valve seat.

Preferably, by providing a dust filter in the ventilation section, the dust generated from the first sealing material and the dust that has been rolled up are captured by the dust filter.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. 1A and 1B show a configuration of an embodiment of a vacuum valve according to the present invention. FIG. 1A is a front view, FIG. 1B is a rear view, and FIG. 1C is a sectional view taken along the line AA ′ of FIG. is there.

In the present embodiment, the vacuum valve 1 includes a valve rod 2 which is opened and closed in the e and f directions by a drive mechanism (not shown), and a plate-shaped first rod connected to the tip of the valve rod 2.
2 and a second valve body 4 arranged between the first valve body 3 and the valve seat 9. The valve rod 2 and the first valve body 3 are attached at a predetermined rotation by attaching the tip of the valve rod 2 inserted between the two attachment portions 3c fixed to the first valve body 3 with a pin 2a. It is connected with the freedom of movement.
The first valve body 3 and the second valve body 4 are respectively formed with circular grooves 3a and 4a, and the first seal 5 and the second seal 6 are attached and fixed therein. There is.

As the material for the first and second seals 5 and 6, a commonly used material such as a gasket manufactured by Viton can be used.

The first valve body 3 is provided with a plurality of guide holes 3b, in this example, three guide holes 3b on the outer circumference of the first seal 5. A base end of a guide shaft 7 is fixed to the second valve body 4, and the guide shaft 7 is inserted into a guide hole 3b provided in the first valve body 3. Guide hole 3
The inner diameter of b is sufficiently larger than the outer diameter of the guide shaft 7,
Even if the valve body 3 moves with respect to the second valve body 4, the guide shaft 7 and the guide hole 3b are prevented from coming into contact with each other. A stopper 7a is formed at the tip of the guide shaft 7, and a coil spring 8 is mounted between the stopper 7a and the first valve body 3. The coil spring 8 is in a non-compressed state when the valve is opened, and the gap between the first seal 5 of the first valve body 3 and the second valve body 4 has a full opening stroke s ₀ .

A hole 4b as a ventilation portion is formed in the center of the second valve body 4. This hole 4b is for alleviating a sudden pressure change from the vacuum state when the valve is opened.
The number, diameter, and hole position can be set according to the degree of differential pressure, dust generation, and dust source. The effect of reducing the pressure change by the hole 4b suppresses the dust from being rolled up, and the effect of suppressing the intrusion of dust into the vacuum chamber is improved. However, in order to further collect the dust, the dust filter 4c is attached to the hole 4b. ing.

Next, the operation of this embodiment will be described with reference to FIG. First, in the valve closed state of FIG. 2 (a) in which the valve rod 2 is operated in the direction e, the first valve body 3 and the second valve body 4 are brought into close contact with the valve seat 9 side by the force of the valve rod 2. And the action of the first and second seals 5 and 6 causes the vacuum chamber 1 to
The inside of 0 is kept in a sealed state. At this time, the coil spring 8 is in an extended state.

Next, from the valve closed state of FIG. 2 (a) to FIG.
As shown in (b), the valve rod 2 is opened in a predetermined direction in the direction of f.
Release stroke s₁Just move. This first open stro
Ark₁From the state shown in FIG. 2 (a),
Although the seal 5 of 1 separates from the second valve body 4,
The second seal 6 of No. 4 is the valve seat 9 side by the urging force of the coil spring 8.
Is the distance to move to the state of being in close contact with. That is,
The second valve body has the above-mentioned full opening stroke s.₀And primary opening
Stroke s₁Difference of compression stroke s = s ₀-S₁
Therefore, the valve seat 9 is compressed. In this state, the hole
An air flow is generated from the valve box side to the vacuum chamber 10 through 4b.
However, the sudden pressure change is eased by the passage resistance of the hole 4b.
To be done. Therefore, dust around the valve body is not rolled up.
It gets harder. In addition, the dust filter installed in the hole 4b
As the air flow passes through the filter 4c, the first seal 5
From the dust generated from the coil spring 8 or
Captures dust from the high pressure side valve box (not shown).

When the valve rod 2 is further opened with the pressure difference between the inside of the vacuum chamber 10 and the valve box side being reduced, FIG.
As shown in FIG. 5, the biasing force of the coil spring 8 disappears, the second valve body 4 also moves together with the first valve body 3, and the second seal 6 also leaves the valve seat 9. At this time, the vacuum chamber 1
Since the differential pressure between 0 and the valve box is alleviated or eliminated, the rolling up of dust from the second seal 6 due to the differential pressure can be reduced.

The step of operating the valve rod 2 from the valve closed state (a) to the valve opening operation state (b) to the valve open state (c) shown in FIG. During the continuous transition to the state (c), the valve rod 2 is gradually and continuously so as to secure a time for eliminating the pressure difference between the vacuum chamber 10 and the valve box in the valve opening operation state (b). A method of moving the valve rod 2 and a method of temporarily stopping the valve rod 2 in the valve opening operation state (b) and shifting to the valve opening state (c) at the timing when the pressure difference between the vacuum chamber 10 and the valve box is eliminated. You can

In this embodiment, the coil spring 8 is used as the urging means for urging the second valve body 4 toward the valve seat 9 in the valve opening operation state, but other urging means,
For example, various springs such as a spiral spring and a leaf spring, a buffer mechanism such as a dashpot, and magnetic means utilizing the attraction or repulsion action of a permanent magnet can be used.

The dust filter 4 mounted in the hole 4b
c has a function of capturing dust particles from the first seal 5 and dust winding due to the differential pressure when the valve is open, scattered to the high vacuum side. As the dust filter 4c,
A fibrous material such as a fluororesin, a porous ceramic such as a gas filter, or a metal sintered body can be used. When the dust filter 4c itself has a ventilation resistance that absorbs a sudden pressure change, the hole 4b does not need to be a small diameter hole, and may have a diameter for mounting the dust filter 4c.

[0023]

As described above, the present invention has the following effects.

(1) According to the invention described in claim 1, the process of opening the vacuum valve by providing the second valve body having the ventilation portion between the first valve body and the valve seat. First, the first valve body separates from the second valve body, but the second valve body is still in the closed state. Therefore, the inside of the vacuum chamber is passed from the ventilation portion of the second valve body through the valve seat. The outside air is introduced into the chamber, and at this time, the aeration portion reduces the sudden pressure change due to the differential pressure when the vacuum valve is opened. Therefore, it is possible to suppress the dust from being wound up, reduce the dust generated from the first seal attached to the first valve body, and further suppress the scattering of the dust.

(2) According to the second aspect of the present invention, by providing the dust filter in the ventilation portion, the dust generated from the first seal and the rolled-up dust can be captured by the dust filter. Therefore, the low dust generation according to claim 1,
In addition to the effect of suppressing dust scattering, it is possible to further suppress the intrusion of dust in the vacuum chamber. This eliminates the need to use a special dust-prevention material as the material of the first seal, which eliminates the cost increase of the seal material and eliminates the need for frequent replacement of the seal material, thus reducing the number of steps. Can be planned. This further reduces the occurrence of defects in products such as semiconductors processed in the vacuum chamber, and improves product quality.

(3) According to the invention described in claim 3 or 4, the adjusting means includes a guide shaft having a base end fixed to the outside of the second seal of the second valve body, and the first adjusting means. By having a guide hole that is provided outside the first seal in the valve body and through which the guide shaft can be inserted, and a spring that is provided between the tip end portion of the guide shaft and the first valve body. Even if the second valve body moves with respect to the first valve body, the guide shaft and the guide hole do not come into contact with each other, so that dust is not generated due to rubbing. Further, since the guide shaft, the guide hole, and the spring are arranged outside the seal, even if dust is generated, it is outside the seal, and it is possible to suppress or prevent dust generation.

[Brief description of drawings]

1A and 1B show a configuration of an embodiment of a vacuum valve according to the present invention, FIG. 1A is a front view, FIG.
(C) is an AA 'sectional view of (a).

FIG. 2 is an explanatory view showing the operation of the valve element according to the vacuum valve opening operation of the embodiment of the present invention.

FIG. 3 is a sectional view showing a structure of a conventional vacuum valve.

[Explanation of symbols]

1 vacuum valve 2 valve rod 2a pin 3 First valve body 3a groove 3b guide hole 3c mounting part 4 Second valve body 4a groove 4b hole 4c dust filter 5 First seal 6 Second seal 7 Guide shaft 7a stopper 8 coil spring 9 seat 10 vacuum chamber

Claims (4)

[Claims] 1. A plate-shaped first valve body, the movement of which is controlled in accordance with an opening / closing operation, and the first valve body, which is disposed between the first valve body and the valve seat, and is interlocked with the first valve body. A second valve element to be driven, a first seal attached to a contact portion of the first valve element with the second valve element, and a contact with the valve seat of the second valve element And a second seal attached to the first valve body, and when the first valve body is opened, the first stage maintains the contact state between the valve seat and the second valve body in the first stage. A second valve for the first valve body such that the valve body opens from the second valve body, and in a second stage following the first stage, the second valve body opens from the valve seat. A vacuum valve comprising: an adjusting unit that adjusts the movement of the body; and a ventilation portion provided inside the second seal of the second valve body. 2. The vacuum valve according to claim 1, wherein a dust filter is provided in the ventilation part. 3. The guide means includes a guide shaft having a base end fixed to an outer side of the second seal of the second valve body, and an outer side of the first seal of the first valve body. The vacuum valve according to claim 1, further comprising: a guide hole provided in the guide shaft, through which the guide shaft can be inserted, and a spring provided between a tip end portion of the guide shaft and the first valve body. 4. The guide means includes a guide shaft having a base end fixed to an outer side of the second seal of the second valve body, and an outer side of the first seal of the first valve body. The vacuum valve according to claim 2, further comprising: a guide hole that is provided in the guide hole and through which the guide shaft can be inserted; and a spring that is provided between a tip end portion of the guide shaft and the first valve body.