JP2000081155A - Gate valve for vacuum - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gate valve for a vacuum to reliably exhibit sealing performance by a constant fastening pressure without being insufficient in a seal pressure and perform reversible use. SOLUTION: When a valve element 46 is moved in the direction in which the valve element seats a valve element support seat and a valve is closed, the taper surface of the valve element is guided by a taper surface formed on the inner end face of the support seat partition wall 26 of a valve box body and seats the valve element support seat and sealing is effected by a first seal part 62 and a first seal seat surface 32, and a second seal part 68 and a second seal seat surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gate valve for vacuum provided between a vacuum chamber and an external atmosphere or between vacuum chambers.

[0002]

2. Description of the Related Art In the manufacture of semiconductors such as silicon wafers, the manufacture of thin films, and the manufacture of liquid crystals, processing and processing of workpieces such as ion plating and plasma etching are performed in a clean environment in a high vacuum. .

[0003] In a vacuum apparatus used for this purpose, a work is once carried into a preparatory chamber, a predetermined degree of vacuum is set in the preparatory chamber, and then the work is successively carried into a processing chamber, a processing chamber, etc., and processed and processed. And so on. Also,
A vacuum gate valve with high sealing and airtightness is provided at the loading / unloading port between these spare chambers, the processing chamber, the processing chamber, etc., and the degree of vacuum and the clean conditions of the processing chamber and the processing chamber are constant. Is to be maintained.

[0004] Such a vacuum gate valve is shown in FIG.
13 to FIG. That is,
The gate valve for vacuum 100 is a valve body 10 having a box shape.
2, a substantially rectangular gate opening 108 formed in the opposed longitudinal side surface 106 penetrating through the lower space 104. A receiving partition 114 is formed in a direction perpendicular to the gate opening 108, extends inward from the four side walls of the valve body 102, and partitions the upper space 110 and the lower space 104 of the valve body. Is formed. A seal seating surface 122 is formed that constitutes a valve body seat that is inclined inward in the longitudinal direction and extends to the inner bottom wall 120 of the valve box main body from both end portions 116 and 118 in the longitudinal direction of the seating partition. A valve body 130 is provided which is movable in a direction to be seated and separated from the valve body receiving seat in a vertical direction via a valve body opening 124 formed in a direction perpendicular to the gate opening 108.

[0005] Then, as shown in FIG.
0 tapered surface 134 sloped inward below base end 132
A ring-shaped first seal member 138 is mounted in the seal groove 136 formed at the bottom, and when the valve body 130 is lowered downward to close the valve body, a seal surface formed on the upper surface of the receiving partition 114. 139. Further, the valve body 130 has a valve plate main body 1 having a shape complementary to a valve body receiving seat extending downward from the base end 132.
40 are provided. A second seal groove 144 is formed in a valve plate side peripheral portion 142 that is complementary to the seal seat surface 122 of the valve plate body 140, and a second seal groove 144 is formed in the second seal groove 144.
The seal member 146 is attached, and when the valve body 130 is moved downward to close the valve body, a seal is formed between the valve body 130 and the seal seat surface 122.

[0006] In the vacuum gate valve configured as described above, the gate opening 108 is opened by moving the valve element 130 up and down by the driving device to move it above the gate opening 108, and the reverse of these. The operation is configured to close the gate opening 108.

[0007]

By the way, these days,
With the increase in the size of semiconductor wafers, liquid crystals, and the like, the shape of the gate opening of the vacuum gate valve is changed from a circular shape to a large-diameter shape such as a rectangular shape, and the valve body itself is also increasing in size. Therefore, the sealing area of the valve body increases, and when the chamber on one side is evacuated and the other side is used at a pressure difference of about 1 atm such as the atmospheric pressure, the force acting on the valve body increases. I have.

For this reason, normally, a vacuum gate valve is designed in advance so that the side on which the valve body is pressed by the pressure difference is the vacuum side, and the side on which the valve body is pressed is the atmospheric side. Since the pressure to press against is limited because the interference of the sealing material is limited, it was possible to cope with the case where the sealing area of the opening is small, but with such a large size, Insufficient sealing pressure may result in reduced sealing performance.

Recently, a vacuum processing apparatus called a multi-chamber system has been developed for the purpose of downsizing and cost reduction. As shown in FIG. 14, the vacuum processing apparatus 200 used in this multi-chamber system has a plurality of vacuum chambers 204 to perform a plurality of different processing and processing around a common vacuum chamber 202 provided at the center. 209 is provided between the vacuum chamber and the common vacuum chamber 202.
Is provided. Then, via a robot 212 provided in a common vacuum chamber, a material D to be processed, such as a wafer, is taken in and out of each vacuum chamber via a gate valve for processing. The processed material D that has been processed is stored in a vacuum storage cassette 214 via a vacuum chamber 211 for taking in and out.

[0010] In such a multi-chamber system, one side is set to atmospheric pressure and the other side is evacuated, or one of the vacuum chambers is made ultra-vacuum and the other vacuum chamber is used as a vacuum. In some cases, operations such as switching and using these in reverse are performed in terms of processes and the like.

In such a case as well, in order to cope with the back pressure, conventionally, the pressure for pressing the valve body against the toilet seat is increased, and a further pressing pressure is generated against the back pressure. The sealing force has been increased so that the sealing can be performed.

[0012] However, such a pressing pressure has a limit due to a limited interference of the sealing material.
As indicated by the dashed line 5 in FIG. 5, the valve element 130 is pushed to the lower pressure side and moved by the pressure from the higher pressure side. Therefore, the valve body 13 on the higher pressure side
The tightening force of the first seal member 138 of the 0 base end 132 is insufficient, and the airtightness may not be maintained. Therefore, in practice, the reverse sealing can be dealt with when the sealing area of the opening is small, but it is practically impossible to deal with the case where the size of the opening becomes large. It was impossible.

On the other hand, conventionally, when a vacuum gate valve is used, in order to remove impurities and maintain a vacuum state in a clean environment, the entire vacuum gate valve needs to be two-hole.
Baking is performed by heating to about 00 ° C. In this case, the baking is performed by heating with a heating device such as an external ribbon heater disposed outside the valve box of the vacuum gate valve.

However, in such a method of heating from the outside of the valve box, the space between the valve box and the valve body causes insufficient heating of the valve body and the vicinity thereof, resulting in insufficient baking without uniform heating. And impurities may be mixed.

In view of the above-mentioned situation, the present invention can maintain a constant size even if the sealing area of the valve body becomes large due to the enlargement of the gate opening and the enlargement of the diameter due to the enlargement of the size of the semiconductor wafer or liquid crystal. An object of the present invention is to provide a vacuum gate valve capable of reliably exerting sealing performance without insufficient sealing pressure due to the tightening pressure of.

Further, the present invention ensures that a certain tightening pressure can be used to reliably seal even in the case where the atmospheric pressure side and the vacuum side are switched from the surface of a film forming process such as a multi-chamber system in reverse. It is an object of the present invention to provide a vacuum gate valve that can be used without any possible directivity of positive pressure and reverse pressure.

Further, according to the present invention, even when heating is performed by a heating device such as an external ribbon heater disposed outside the valve box of the vacuum gate valve during baking, the valve body and its vicinity are also uniformly heated. It is an object of the present invention to provide a vacuum gate valve which can bake the entirety of the vacuum gate valve without any impurities and can provide a clean environment.

[0018]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned objects and objects, and a vacuum gate valve according to the present invention has a lower space below a box-shaped valve body. And a gate opening formed in the opposed longitudinal side surface, and extending inward from four sidewalls of the valve box body in a direction perpendicular to the gate opening, and an upper space of the valve box body. And a lower space, and a seating partition constituting a valve body seat having a first seal seating surface formed on the upper surface thereof in a direction perpendicular to the gate opening, and a longitudinal direction of the seating partition. A second seal seat surface that constitutes a valve body seat extending from both end portions downward in the longitudinal direction to the inner bottom wall of the valve box body, and a direction perpendicular to the gate opening by the seat partition; Through the valve body opening formed in A valve body movable in a direction to be seated and separated from the valve body seat, wherein the valve body is formed at a valve body base end portion connected to a drive shaft, and a second one of an upper surface of the seat partition wall. (1) a first contact surface formed in a direction perpendicular to the gate opening contacting the seal seat surface, and a tapered surface formed so as to be inclined inward downward from the first contact surface. A first seal formed on the first contact surface, the valve seal body extending downward from the tapered surface, and having a shape complementary to a second seal seat surface of the valve body receiving seat. A first seal portion of a seal member is mounted in the groove, and a second seal groove formed in a valve plate side peripheral portion that abuts on a second seal seat surface of the valve box body in the valve plate body. The second seal portion of the member is mounted, and the inner end surface of the receiving partition of the valve body is complementary to the tapered surface of the valve body. The valve body has a tapered surface inclined inward in a downward direction, and when the valve body is moved in a direction to be seated with respect to the valve body receiving seat to close the valve, the tapered surface of the valve body is The first seal portion, the first seal seat surface, and the second seal portion are guided by a tapered surface formed on the inner end surface of the receiving partition of the box body and seated on the valve body receiving seat. The second seal seat surface is configured to seal.

With this configuration, when the valve is closed, the tapered surface of the valve body is guided by the tapered surface formed on the inner end surface of the receiving partition of the valve body, and the valve body receiving seat is closed. And the two tapered surfaces coincide with each other at that time, so that the valve element is fixed to the valve element receiving seat.

Therefore, even if the valve element is pushed by the pressure difference, the valve element does not move, so that the tightening force of the sealing member does not loosen and the sealing performance does not decrease. In addition, since the seal member is pressed in a direction perpendicular to the seal seat surface of the valve seat, the seal member is subjected to only a compressive load without being affected by twisting or the like. Good. Further, since there is no movement of the valve element due to the pressure difference, either side of the valve element, the atmosphere side, the vacuum side, that is,
Since the sealing property can be secured on both the positive pressure side and the reverse pressure side,
It can be used without directivity of positive pressure and reverse pressure.

The vacuum gate valve according to the present invention is characterized in that a heater for baking the valve body and its vicinity is embedded inside the valve body. Accordingly, even when heating is performed by a heating device such as an external ribbon heater arranged outside the valve box of the vacuum gate valve during baking, the temperature of the valve body and its vicinity can be uniformly increased, and the temperature can be reliably increased. The entire vacuum gate valve can be baked,
A clean environment can be provided without contamination.

Furthermore, the vacuum gate valve according to the present invention
A thermocouple for controlling the temperature of the heater is provided inside the valve body. Thus, the temperature of the valve element and its vicinity during baking can be controlled, so that the entire gate valve can be uniformly baked.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments (examples) of the present invention will be described with reference to the drawings. FIG. 1 is a partial sectional front view of a first embodiment of a vacuum gate valve of the present invention, FIG. 2 is a perspective view of a valve body of the vacuum gate valve of FIG. 1, and FIG. 4 is a side view of the seal member used for the vacuum gate valve of FIG. 1, FIG. 5 is a left side view of the seal member used for the vacuum gate valve of FIG. 1, FIG.
A- of FIG. 1 showing a closed state of the vacuum gate valve of FIG.
7 is a partially enlarged view showing a state immediately before the state shown in FIG. 6, and FIG. 8 is a sectional view showing an open state of the vacuum gate valve shown in FIG. It is sectional drawing.

As shown in FIG. 1, the vacuum gate valve 10 comprises a box-shaped valve box main body 12 and a drive box 14 provided on the upper part thereof. The valve box main body 12 is provided with substantially rectangular gate openings 22 and 24 formed on the opposed longitudinal side surfaces 11 and 13 through the lower space 16 thereof.

A receiving partition 26 extends inward from the four side walls 17 to 20 of the valve body 12 in a direction perpendicular to the gate openings 22 and 24.
The upper space 2 formed above the valve body 12
8 and a lower space 30 are defined. This seat bulkhead 2
6 has a first seal seat surface 32 forming a valve body seat C.
Is composed. In addition, the receiving partition 26 forms a valve opening 34 having a substantially elliptical shape in a direction perpendicular to the gate openings 22 and 24.

In the lower space 30, as shown in FIG.
Partitioned into the inner side walls 12a to 12d of the valve box main body 12, from the both end portions 36, 38 in the longitudinal direction of the receiving partition 26, through inclined surfaces 40, 42 inclined inward in the longitudinal direction downward,
A second seal seat surface 44 constituting a valve element seat C extending to the inner bottom wall 12d of the valve box body 12 is formed.

On the other hand, a valve body movable by a drive mechanism 15 provided in the drive box 14 in a direction to be seated and separated from the valve body receiving seat C vertically through the valve body opening 34. 46 is provided. The valve body 46 is connected to a drive shaft 48, and a first contact surface 52 is formed on the lower surface of the valve body base end 50 in a direction perpendicular to the gate openings 22 and 24. This first contact surface 52
Are in contact with a first seal seat surface 32 formed in a direction perpendicular to the gate openings 22 and 24 on the upper surface of the seat partition 26. A tapered surface 54 inclined inward downward from the first contact surface 52 is formed, and the second seal seat surface 4 of the valve body receiving seat C is formed downward from the tapered surface 54.
A valve plate body 56 having a shape complementary to that of the valve plate 4 is formed.

As shown in FIGS. 6 to 8, the first contact surface 5 formed on the lower surface of the valve element base end 50 of the valve element 46.
The first seal groove 58 is formed in the second seal groove 2, and the ring-shaped first seal portion 62 of the seal member 60 is formed in the first seal groove 58.
Is installed. Thereby, when the valve body 46 is lowered and the valve body 46 is closed, the valve body 46 is sealed with the first seal seat surface 32 formed on the upper surface of the receiving partition 26.

The second seal seat surface 44 of the valve plate body 56
A second seal groove 66 is formed in the valve plate-side peripheral portion 64 in contact with the second seal seat surface 4.
A second seal portion 68 having a shape complementary to that of the second seal seat 4 is provided, so that when the valve body 46 is lowered to close the valve body, a seal is formed between the second seal portion 68 and the second seal seat surface 44. It is supposed to.

Further, the inner end face of the receiving partition wall 26 is
6 has a tapered surface 27 inclined inward in the downward direction that is complementary (coincident) with the tapered surface 54 of the valve body 54. As shown in FIGS. When the valve is moved downward in the seating direction to close the valve, the tapered surface 54 of the valve body 46 is guided by the tapered surface 27 formed on the inner end surface of the receiving partition 26 of the valve box body 12. , And the tapered surfaces 27 and 54 coincide with each other at this time, so that the valve body 46 is fixed to the valve body seat C.

Further, the drive box 14 is provided with the valve box body 1.
The drive shaft 48 connected to the valve body 46 is mounted in a central hole 72 of the bonnet 70 so as to be slidable up and down. A bellows flange 74 is fixed to the upper end of the drive shaft 48.
And between the hood flange 76 of the hood 70
A bellows 78 for securing the sealing performance is fixed.

A drive cylinder 80 as an actuator is provided on the side of the drive box 14. A drive shaft 80 is connected to a piston rod 82 of the drive box 14 by a link 84 rotatably connected via a pivot 83. It is connected to the upper end of 48 via a pin 85. Accordingly, the operation of the drive cylinder 80 causes the drive shaft 48
Is moved up and down to move the valve body 46 above the gate openings 22, 24, thereby opening the gate openings 22, 24, and closing the gate openings 22, 24 by the reverse operation. It is configured as follows.
In the drawing, 87 and 89 are air supply pipes connected to an air supply source (not shown) for driving the drive cylinder 80.

In the vacuum gate valve of the present invention constructed as described above, by operating the drive cylinder 80, the link 84 is rotated, the drive shaft 48 is lowered, and the valve body 46 is lowered. , The tapered surface 54 of the valve body 46 is guided by the tapered surface 27 formed on the inner end surface of the receiving partition 26 of the valve body, and seats on the valve body receiving seat C. 27 and 54 coincide, and the valve body 46 is fixed to the valve body seat C.

That is, the first seal portion 6 of the valve plate body 56
2 and a first seal seating surface 3 formed on the upper surface of the receiving partition 26
2 and between the second seal portion 68 and the second seal seat surface 44 are securely sealed.

Moreover, even if the valve element 46 is pushed by the pressure difference, the valve element 46 does not move, so that the tightening force of the sealing member does not loosen and the sealing performance does not decrease. Further, since the seal member is pressed in a direction perpendicular to the two seal seat surfaces 32 and 44 of the valve body receiving seat C, the seal member is not affected by torsion or the like and receives only a compressive load. Its sealing properties are very good. In addition, since the valve element does not move due to the pressure difference as described above, the sealing performance can be ensured regardless of which side of the valve element is sandwiched between the atmosphere side and the vacuum side, that is, the positive pressure side and the reverse pressure side. It can be used without directivity of pressure and back pressure.

In the above-described embodiment, the drive shaft 48 is connected to the piston rod 82 of the drive cylinder 80 by a connection link as the drive mechanism, but the drive cylinder is connected to the drive shaft without using such a connection link. It is of course also possible to dispose it above and connect it directly to the piston rod.

FIG. 9 is a front sectional view of a second embodiment of the vacuum gate valve according to the second embodiment of the present invention, and FIG. 10 is a view in the direction of arrow B in FIG. The vacuum gate valve of this embodiment has basically the same configuration as the above-described vacuum gate valve of the first embodiment, and the same components are denoted by the same reference numerals and will be described in detail. Is omitted.

In the vacuum gate valve 10 of this embodiment, a substantially oblong cartridge heater 90 for baking the valve body 46 and its vicinity is embedded in the valve plate body 56 of the valve body 46. Further, a thermocouple 92 for controlling the temperature of the heater is disposed inside the valve plate body 56 of the valve body 46 on the inner peripheral side of the cartridge heater 90. A connector 94 is provided on the side of the drive box 14.
And a lead wire 96 of the heater 90 and a lead wire 98 of the thermocouple 92 are connected via a connector 94 to a power supply and a control device (not shown) provided outside. Lead wires 96 and 98 pass through the center of the drive shaft 48 and are connected to a cartridge heater 90 and a thermocouple 92 in the valve plate body 56, respectively.

Thus, even when heating is performed by a heating device such as an external ribbon heater separately arranged outside the valve box of the vacuum gate valve 10 during baking, the valve body 46 and the vicinity thereof are also controlled by the cartridge heater. The temperature can also be raised uniformly, the entire gate valve for vacuum can be reliably baked, and a clean environment can be provided without contamination. Further, since the thermocouple 92 is provided, the temperature of the valve body and its vicinity during baking can be controlled, so that the entire gate valve can be baked uniformly.

The temperature of the valve plate body 56 of the valve body 46 can be uniformly increased by selecting a material having excellent temperature increasing characteristics, such as an aluminum alloy.

[0041]

According to the vacuum gate valve of the present invention,
When closing the valve, the tapered surface of the valve body is guided by the tapered surface formed on the inner end surface of the receiving partition of the valve body,
The seat is seated against the valve body seat, and at this time, the two tapered surfaces coincide with each other, so that the valve body is fixed to the valve body seat.

Therefore, even if the valve element is pushed by the pressure difference, the valve element does not move, so that the tightening force of the sealing member does not loosen and the sealing performance does not decrease. In addition, since the seal member is pressed in a direction perpendicular to the seal seat surface of the valve seat, the seal member is subjected to only a compressive load without being affected by twisting or the like. Good.

Therefore, even if the sealing area of the valve body becomes large due to the enlargement and large diameter of the gate opening accompanying the enlargement of the size of the semiconductor wafer, the liquid crystal, etc., the sealing pressure becomes insufficient due to the constant tightening pressure. It is possible to provide a vacuum gate valve capable of reliably exerting sealing performance without using the same.

Further, since the valve element does not move due to the pressure difference, the sealing performance can be ensured regardless of which side of the valve element is sandwiched between the atmosphere side and the vacuum side, that is, the positive pressure side and the reverse pressure side. Therefore, even when switching from the atmospheric pressure side to the vacuum side from the surface of the film forming process such as the multi-chamber system, the seal can be reliably sealed with a certain tightening pressure, positive pressure, reverse pressure The gate valve for vacuum which can be used reversibly without the directionality of the above can be provided.

Further, when heating is performed by a heating device such as an external ribbon heater disposed outside the valve box of the vacuum gate valve during baking, the temperature of the valve body and its vicinity can be uniformly increased. Thus, the entire vacuum gate valve can be reliably baked, and a clean environment can be provided without contamination. In addition, since the temperature of the valve body and its vicinity during baking can be controlled, it is possible to uniformly bake the entire gate valve.

[Brief description of the drawings]

FIG. 1 is a partial sectional front view of a first embodiment of a vacuum gate valve of the present invention.

FIG. 2 is a perspective view of a valve body of the vacuum gate valve of FIG. 1;

FIG. 3 is a top view of a sealing member used for the vacuum gate valve of FIG. 1;

FIG. 4 is a side view of a sealing member used for the vacuum gate valve of FIG. 1;

FIG. 5 is a left side view of a seal member used for the vacuum gate valve of FIG. 1;

FIG. 6 is a cross-sectional view taken along line AA of FIG. 1 showing a closed state of the vacuum gate valve of FIG. 1;

FIG. 7 is a partially enlarged view showing a state immediately before the state of FIG. 6;

FIG. 8 is a cross-sectional view taken along line AA of FIG. 1 showing an open state of the vacuum gate valve of FIG. 1;

FIG. 9 is a front sectional view of a second embodiment of the vacuum gate valve according to the second embodiment of the present invention.

FIG. 10 is a view in the direction of arrow B in FIG. 9;

FIG. 11 is a front view of a conventional vacuum gate valve.

FIG. 12 is a partial sectional front view of a conventional vacuum gate valve.

FIG. 13 is a cross-sectional view of a conventional vacuum gate valve.

FIG. 14 is a schematic view showing a conventional multi-chamber type vacuum processing apparatus.

FIG. 15 is a schematic diagram illustrating an operation state of a conventional vacuum gate valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vacuum gate valve 12a Inner side wall 12d Inner bottom wall 12 Valve box main body 14 Drive box 15 Drive mechanism 22, 24 Gate opening 26 Receiving partition 27 Tapered surface 28 Upper space 30 Lower space 32 Seal seat surface 34 Valve opening Part 36 Both end portions 40 Inclined surface 44 Seal seat surface 46 Valve element 48 Drive shaft 50 Valve element base end part 52 Contact surface 54 Tapered surface 56 Valve plate body 58 Seal groove 60 Seal member 62 Seal part 64 Valve plate side peripheral part 66 Seal groove 68 Seal portion 70 Bonnet 72 Central hole 74 Bellows flange 76 Bonnet flange 78 Bellows 80 Drive cylinder 82 Piston rod 83 Pivot 84 Link 85 Pin 90 Cartridge heater 92 Thermocouple 94 Connector 96 Heater lead wire 98 Lead wire

Claims (3)

[Claims] 1. A gate opening formed in opposed longitudinal side surfaces through a lower space of a box-shaped valve body, and a valve opening of the valve body in a direction perpendicular to the gate opening. A valve body seat that extends inward from the four side walls and defines an upper space and a lower space of the valve box main body, and has a first seal seat surface formed on its upper surface in a direction perpendicular to the gate opening. And a second seal seat surface which constitutes a valve body seat which inclines downward in the longitudinal direction from both end portions in the longitudinal direction of the seat bulkhead to the inner bottom wall of the valve box body. And a valve body movable vertically in a direction to be seated and separated from the valve body seat through a valve body opening formed by the seat partition wall in a direction perpendicular to the gate opening. The valve body is formed at a valve body base end connected to a drive shaft. A first contact surface formed in a direction perpendicular to a gate opening contacting a first seal seat surface on an upper surface of the receiving partition; and a downward inward direction from the first contact surface. A tapered surface formed so as to be inclined; and a second portion of the valve body receiving seat that extends downward from the tapered surface.
A valve seat body having a complementary shape to the seal seat surface, and a first seal portion of a seal member is mounted in a first seal groove formed in the first contact surface; A second seal portion of a seal member is mounted in a second seal groove formed in a valve plate side peripheral portion that abuts on a second seal seat surface of the valve box body. An inner end surface has a tapered surface inclined inward in a downward direction complementary to the tapered surface of the valve body, and the valve body is moved in a direction in which the valve body is seated with respect to the valve body receiving seat. When closing the, the tapered surface of the valve body is guided by the tapered surface formed on the inner end surface of the receiving partition of the valve body,
A vacuum gate, which is configured to be seated on the valve body receiving seat and sealed by the first seal portion and the first seal seat surface and the second seal portion and the second seal seat surface. valve. 2. A vacuum gate valve according to claim 1, wherein a heater for baking the valve body and its vicinity is embedded inside the valve body. 3. The vacuum gate valve according to claim 2, wherein a thermocouple for controlling a temperature of the heater is provided inside the valve body.