JPH0989139A - Vacuum opening/closing valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an opening/closing valve formed of a body having a satisfactory thermal conductivity by providing a main valve body having a cylindrical part enclosing the valve element and a plane port constituting a valve seat abutting against the valve element molded integrally with the same member. SOLUTION: A valve part 3 is constituted from a valve structure provided in a body 21 fitted in a cylinder adapter 5. The body 21 constituting the valve part 3 has a valve seat 25 constituted from one metallic tube by drawing. The tube is formed axially with an input port and vertically with an output port 23. Also, a valve element 24 sandwiching an O-ring 27 with a disk 26 is fixed to the lower end of a rod 6. The inside plane part of the body 21 formed with the input port 22 constitutes the valve seat 25 abutting against the valve element 24 in closing the valve. While a vacuum switch valve 1 has the body 21 heated by a heater 35 covered with a heat insulating material 36, the body 21 is molded with the nearly uniform thickness to improve considerably the thermal conductivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum on-off valve used in an exhaust system of a vacuum processing apparatus such as a semiconductor manufacturing process, and more particularly to a vacuum on-off valve excellent in preventing fluid from adhering to a pipe. .

[0002]

2. Description of the Related Art First, a vacuum pressure control system in a semiconductor manufacturing process will be described as an example of use of a vacuum on-off valve with reference to the drawings. FIG. 6 is a diagram showing the configuration of the entire system. Wafers 92 are arranged stepwise inside a vacuum chamber 91 which is a vacuum container. The vacuum chamber 91 is formed with an inlet 91a and an outlet 91b, and a source of process gas and a source of nitrogen gas for purging the inside of the vacuum chamber 91 are connected to the inlet 91a. On the other hand, the outlet 91b is connected to the input port of the vacuum on-off valve 51 which is a bellows type poppet valve. An output port of the vacuum on-off valve 51 is connected to a vacuum pump 94 via a valve opening proportional valve 93 which is a butterfly type opening adjustment valve.

Further, the pressure sensor 95 measures the vacuum pressure inside the vacuum chamber 91, and feedback control is carried out to the stop position of the step motor of the valve opening proportional valve 93 so that a predetermined vacuum pressure value is obtained. That is, during the manufacturing process, the process gas is supplied to the vacuum chamber 91, and in this vacuum pressure control system, when the vacuum pressure value becomes higher than the target value in the atmospheric pressure direction, the valve opening proportional valve 93 Is increased to increase the vacuum flow rate sucked by the vacuum pump 94. On the contrary, when the vacuum pressure value is lower than the target value toward the absolute vacuum direction, the opening degree of the valve opening proportional valve 93 is reduced to reduce the vacuum flow rate. However, the valve opening proportional valve 93 using the butterfly type proportional valve cannot be completely shut off structurally. Therefore, a shutoff valve such as the vacuum on-off valve 51 is separately connected in series to completely shut off the fluid in the pipe.

Therefore, the structure of a conventional vacuum on-off valve will be described. 4 and 5 are sectional views showing a conventional vacuum on-off valve. FIG. 4 shows a state when the valve is closed, and FIG. 5 shows a state when the valve is open. The vacuum on-off valve 51 includes a cylinder portion 52 and a valve portion 53. Therefore, first, the configuration of the cylinder portion 52 will be described. In the cylinder portion 52, a cylinder cover 54 that opens downward is fitted with a cylinder adapter 55 so as to close the opening. Then, the cylinder rod 56 is inserted so as to penetrate the shaft core portion of the cylinder adapter 55, and the piston 57 fixed to the upper end portion thereof with a nut is positioned by the piston spacer 58 and fitted into the cylinder cover 54. Has been done. The piston 57 is slidably contacted with the inner wall surface so as to slide on the cylinder cover 54, and a PSD packing 59 is attached to a sliding portion on the peripheral edge thereof. A magnet 60 for detecting the piston position from the outside of the cylinder cover 54 by a magnetic sensor (not shown) is attached so as to face the inner wall surface of the cylinder cover 54.

Further, large and small springs 61A and 61B for further urging the piston 57 downward are fitted and inserted in the cylinder cover 54. By the way, the cylinder cover 54 is formed with an exhaust port 62 communicating with the upper chamber 64 above the piston 57 fitted therein, and an exhaust cap 63 is attached thereto. On the other hand, an air supply port 66 is formed in the lower chamber 65 below the piston 57.

Next, the valve portion 53 is a cylinder adapter-5.
5 Through the bellows adapter 71 on the lower end surface, the body 72
Are fitted. The body 72 includes a thin body tube 72a and a thick valve seat portion 7a.
2b. The body tube 72a
Has an output port 75 protruding in the lateral direction, and one valve seat portion 72b has an input port 73 formed by a valve hole formed in the valve seat 74. A valve rod 76 is coaxially connected to the lower end of the cylinder rod 56 of the cylinder portion 52 and fitted into the body tube 72a. A valve body 78 having an O-ring 77 is fixed to the lower end of the valve rod 76 so as to come into airtight contact with the valve seat 74.

In the body tube 72a, a bellows 79, which is welded and connected to the valve body 78 and the bellows adapter 71, is provided so as to cover the valve rod 76. An air vent port 55a is formed in the cylinder adapter 55 and communicates with the inside of the bellows 79. By the way, in a semiconductor manufacturing process in which the vacuum on-off valve 51 is used, in order to prevent fluid from adhering to the inside of the pipe, the body tube 72a of the body 72 is covered with the heater 80 covered with the heat insulating material 81. Has been. Specifically, it is provided so as to surround almost the entire body tube 72a from the output port 75 side and the opposite side. Further, a thermostat 82 for controlling the temperature of the heater 80 is attached at a position opposite to the output port 75.

The vacuum opening / closing valve 51 having such a structure
When compressed air is supplied from the air supply port 66 to the lower chamber 65, the air in the upper chamber 64 is discharged from the exhaust port 62, and the piston 57 is moved against the downward biasing force of the springs 61A and 61B. To rise. When the piston 57 rises, the valve body 78 rises while contracting the bellows 79 via the cylinder rod 56 and the valve rod 76. Therefore, the input port 73 and the output port 75 communicate with each other, and the fluid flows in the valve portion 53. Then, if the supply of the compressed air from the air supply port 66 is stopped, the springs 61A, 61
The elastic force of B lowers the piston 57, and accordingly, the valve element 78, particularly the O-ring 77, comes into airtight contact with the valve seat 74, and the input port 73 and the output port 75 are completely shut off from each other.

By the way, the flow of the fluid is controlled by opening and closing the vacuum on-off valve 51 as described above, while the heater 80
The body 72 is heated by. This is because the product of the process gas used in the semiconductor manufacturing process is deposited at room temperature. Therefore, if the process gas is deposited and adheres to the inside of the valve or the pipe, the airtight closing of the valve is hindered, and the particles that have fallen off adhere to the product, resulting in defective products. Therefore, the conventional vacuum on-off valve 51 heats the heater 80 and heats the body 72 while monitoring the temperature with the thermostat 82 in order to prevent the process gas from depositing and adhering in the middle of the piping. As a result, the temperature of the fluid is raised to prevent precipitation. Usually, in order to prevent the fluid in the pipe from adhering in such a semiconductor manufacturing process, it is preferable to raise the temperature to about 80 to 100 ° C.
In this case, the valve seat 74
As a guide, set the sealing surface of to the target temperature.

[0010]

However, the conventional vacuum on-off valve 51 as described above has the following problems. That is, the body 72 that constitutes the valve portion 53 of the vacuum on-off valve 51 has a very poor thermal efficiency at the time of heating performed by the heater 80 to prevent the adhesion of fluid. This is because the body 72 is formed by combining separate parts of the body tube 72a and the valve seat portion 72b, and the body tube 72a to which the heater 80 is attached is thin, whereas the body seat 72 is thin. Since the portion 72b is formed of a thick member, heat transfer is very poor, and the temperature of the heater 80 for supplying heat and the valve seat portion 7 are increased.
This is because there is a large difference in temperature with the sealing surface of 2b. Therefore, in order to bring the valve seat portion 72b to the target temperature, it is necessary to heat the body tube 72a to about 1.5 to 2 times the target value. Further, such poor heat transfer is not good in that it takes a long time to set the target value.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a vacuum on-off valve composed of a body having good heat transfer in order to solve the above problems.

[0012]

A vacuum on-off valve according to the present invention is provided on a pipe of a vacuum control system in which a vacuum pump sucks fluid in a vacuum container, and by opening and closing the valve, the degree of vacuum in the vacuum container is increased. Characterized in that the cylindrical portion enclosing the valve body and the plane portion constituting the valve seat with which the valve body abuts have a valve body integrally formed by the same member. . Further, in the vacuum on-off valve of the present invention, it is preferable that the flat portion of the valve body is formed by drawing one end of a hollow pipe forming a cylindrical portion. Further, in the vacuum on-off valve of the present invention, it is desirable that the valve body is integrally formed with a substantially uniform wall thickness. Further, in the vacuum on-off valve of the present invention, when the valve body is heated by the heating means provided on the cylindrical portion, the heat supplied to the cylindrical portion by the heating means is efficiently transmitted to the flat surface portion. It is characterized by Further, in the vacuum on-off valve of the present invention, it is preferable that the valve body has a cylindrical portion and a flat portion integrally formed with a cylindrical hole for an input port or an output port.

The vacuum on-off valve of the present invention having such a structure is located on the pipe connecting the vacuum container and the vacuum pump, and opens when the fluid in the vacuum container is sucked by the vacuum pump. If not, the valve is closed to control the degree of vacuum in the vacuum container. At that time, if the fluid sucked by the vacuum pump is a process gas or the like used in the semiconductor manufacturing process, it will be deposited at room temperature and inconvenience will occur, so the valve body is heated by a heater or the like to raise the temperature, INDUSTRIAL APPLICABILITY The vacuum opening / closing valve of the present invention has good heat transfer because the cylindrical portion and the flat portion are integrally formed by the same member, and the temperature of the heater is not excessively raised to raise the temperature to the target temperature. Also, it can be performed in a short time. Further, in the vacuum on-off valve of the present invention, in order to heat the valve body with a heater or the like to raise the temperature, the flat portion of the valve body is formed by drawing one end of the hollow pipe forming the cylindrical portion by connection. Since it is integrally molded without a portion, the heat transfer to the valve seat portion is good, and it is possible to raise the temperature to the target temperature without excessively raising the temperature of the heater and in a short time.

Further, in the vacuum on-off valve of the present invention, since the valve body is integrally formed with a substantially uniform thickness in order to heat the valve body with a heater or the like to raise the temperature, The transmission is good, and it is possible to raise the temperature to the target temperature without excessively raising the temperature of the heater and in a short time. Further, in the vacuum on-off valve of the present invention, when the valve body is heated by a heater or the like to raise the temperature, the valve body is integrally formed with a cylindrical hole for an input port or an output port in a cylindrical portion and a flat portion. Since the fluid flowing through the on-off valve absorbs heat sufficiently, it is possible to prevent the fluid from adhering in the middle of the pipe.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of a vacuum on-off valve according to the present invention will be described with reference to the drawings. 1 and 2 are cross-sectional views showing the vacuum on-off valve according to the present embodiment. FIG. 1 shows the valve closed and FIG. 2 shows the valve open.
The vacuum on-off valve 1 of the present embodiment is similar to the conventional one.
Used in vacuum pressure control systems,
It is composed of a cylinder portion 2 and a valve portion 3. Therefore,
First, the structure of the cylinder portion 2 will be described. In the cylinder portion 2, the piston 7 is slidably inserted while the cylinder cover 4 is fitted in the cylinder adapter-5.
Then, penetrate the cylinder adapter-5 to cover the cylinder.
The rod 6 inserted into the screw 4 is screwed to the center of the piston 7. In addition, inside the cylinder cover-4, the piston 7
Is divided into an upper chamber 8 and a lower chamber 9, and an exhaust port 10 communicating with the upper chamber 8 and a supply port 11 communicating with the lower chamber 9 are formed in the cylinder cover-4. Then, in order to maintain the airtightness of the lower chamber 9, an annular adapter 13 provided with a packing 12 is fitted in a sliding contact portion with the rod 6.

Next, the valve portion 3 is constituted by a valve structure provided in the body 21 fitted to the cylinder adapter-5. The body 21 forming the valve portion 3 is formed by drawing from a single metal tube to form a valve seat 25, and an input port 22 is formed in the axial direction of the tube and an output port 23 is formed in the vertical direction (details). Will be described later). Further, a valve body 24 holding an O-ring 27 by a disc 26 is fixed to the lower end of the rod 6. This valve body 2
4 and the disk 26 are screwed to the tip of the rod 6 with a bolt 28 so as to be removable.
The inner flat surface portion of the body 21 in which the input port 22 is formed constitutes the valve seat 25 with which the valve body 24 abuts when the valve is closed.

Further, spring retainers 29 and 30 are provided on the upper portion of the valve body 24 and the lower portion of the annular adapter 13, and a spring 31 for biasing the valve body 24 toward the valve seat 25 surrounds the rod 6. It is fitted. Further, a bellows adapter 32 is fitted between the cylinder adapter-5 and the body 21, and the bellows adapter 32 and the valve body 24 are fitted together.
A bellows 33 welded to and is provided to cover the spring 31. And this bellows 33
A port 5a formed in the cylinder adapter 5 is communicated with the inside for venting the air inside. Further, like the conventional one, the heater 35 and the heat insulating material 36 are covered around the body 21, and the thermostat 37 is attached thereto.

By the way, the body 21 of the present embodiment is formed by using, for example, the following pipe end expanding method. The portion of the material steel pipe to be expanded is subjected to annealing or normalizing heat treatment as a pretreatment for improving the workability. When the steel pipe is hardened by induction heating to increase its strength, it is annealed or standardized before hardening to ensure the workability of the pipe expanding portion. A press working method using a punch is generally applied to the pipe expanding work, but a hydraulic bulge working method or a rubber bulge working method may be used. Then, cold working, warm working or hot working is selected according to the strength of the material and the amount of pipe expansion. The expanded portion of the steel pipe is configured as the body 21, and the portion having the original diameter is configured as the input port 22. Then, a flat surface is formed by punching on the step portion where the diameter is expanded from the input port 22 to the body 21, and further the surface is finished to form the valve seat 25 (flatness 0.05 mm, surface roughness 0.8 μm). Further, an output port 23 is formed in the hole formed in the expanded body 21 by drawing.

The vacuum on-off valve 1 of the present embodiment having such a structure operates as follows. When the valve is opened, compressed air is supplied from the supply port 11 into the lower chamber 9, and upward pressure acts on the piston 7. Therefore piston 7
Is slid upward on the inner peripheral surface of the cylinder cover-4 against the biasing force of the spring 31 by the air pressure. Then, the valve body 24 connected by the rod 6 also rises while compressing the spring 31, so that the input port 22 and the output port 23 communicate with each other apart from the valve seat 25. On the other hand, at the time of closing the valve, if the supply of compressed air to the supply port 11 is stopped, the pressure in the lower chamber 9 drops, and the elastic force of the spring 31 causes the valve body 24 to descend together with the piston 7. Then, the O-ring 27 is pressed against the valve seat 25 and the input port 2
The communication between 2 and the output port 23 is cut off.

The vacuum on-off valve 1 of the present embodiment also has
In order to prevent the process gas from depositing and adhering in the middle of the piping, the heater 35 covered with the heat insulating material 36 is heated while being controlled by the thermostat 37, and the body 21 is heated.
Heating. By the way, in the vacuum on-off valve 1 of the present embodiment, since the body 21 is molded with a substantially uniform thickness as described above, the heat transfer is very good. Therefore, this result will be described in comparison with the conventional one. 3A and 3B are graphs showing changes in temperature of the heater 35 and the body 21, wherein FIG. 3A shows a conventional vacuum on-off valve and FIG. 3B shows this embodiment. Then, especially for the temperature of the body, the seal surface of the valve seat at which the temperature should be raised most was measured.

According to this, in the prior art, it is necessary to raise the temperature of the heater to 160 ° C. to reach the target temperature of 80 ° C., whereas in the present embodiment, the temperature of the heater is increased. Was sufficient at 90 ° C. Further, in the conventional example, even if the temperature of the heater is raised to 160 ° C. in about 0.5 hours, it takes about 1 hour to reach the sealing surface of 80 ° C. In the case of the conventional type, the temperature of the heater was raised to 90 ° C. in about 0.3 hours, and the temperature could be raised in 0.5 hours, which is about half that of the conventional type.

Therefore, in the vacuum on-off valve of the present embodiment having the above-mentioned configuration, it is sufficient to heat the heater at a temperature substantially the same as the target temperature in order to raise the temperature of the body, thus reducing the power consumption. I was able to. In addition, the temperature of the body that is the object of temperature rise can be raised to the target temperature in an extremely short time of about half that of the conventional body, and the time required for startup can be shortened. In particular, the time difference between the temperature rise of the heater and the temperature rise of the body is small, and it can be said that the thermal efficiency is good in this respect.

The vacuum on-off valve of the present invention is not limited to that of the above-described embodiment, and various modifications can be made without departing from the spirit of the invention. For example, in the above embodiment, the pneumatic cylinder is used as the drive source for opening and closing the valve, but a solenoid may be used.

[0024]

The vacuum on-off valve according to the present invention is provided on a pipe connecting a vacuum pump for sucking fluid in the vacuum container and the vacuum pump, and opening and closing the valve causes the vacuum in the vacuum container to be vacuumed. The degree of controlling the degree is characterized in that the cylindrical portion enclosing the valve body and the plane portion constituting the valve seat with which the valve body abuts have a valve body integrally formed by the same member. Therefore, in order to prevent the fluid from adhering to the inside of the valve main body or the pipe, the temperature of the valve main body is raised by a heater or the like. It has become possible.

[Brief description of drawings]

FIG. 1 is a view showing a cross section of an embodiment of a vacuum on-off valve according to the present invention.

FIG. 2 is a view showing a cross section of an embodiment of a vacuum on-off valve according to the present invention.

FIG. 3 is a diagram showing a graph comparing a temperature rising state by a heater of the vacuum on-off valve of the present embodiment with a conventional one.

FIG. 4 is a view showing a cross section of a conventional vacuum on-off valve.

FIG. 5 is a view showing a cross section of a conventional vacuum on-off valve.

FIG. 6 is a diagram showing a configuration of an entire vacuum pressure control system in a semiconductor manufacturing process.

[Explanation of symbols]

 2 cylinder part 3 valve part 21 body 22 input port 23 output port 24 valve body 25 valve seat 35 heater 36 heat insulating material

Claims (5)

[Claims] 1. A vacuum on / off valve for controlling a degree of vacuum in a vacuum container by opening and closing the valve, wherein a vacuum pump is provided on a pipe of a vacuum control system for sucking a fluid in the vacuum container. An on-off valve for vacuum, characterized in that a cylindrical portion and a flat portion constituting a valve seat with which the valve element abuts have a valve body integrally formed by the same member. 2. The vacuum on-off valve according to claim 1, wherein the flat portion of the valve body is formed by drawing one end of a hollow pipe forming a cylindrical portion. Open / close valve. 3. The vacuum on-off valve according to claim 1 or 2, wherein the valve body is integrally formed with a substantially uniform wall thickness. 4. The vacuum on-off valve according to claim 1, wherein when the valve body is heated by a heating means provided on the cylindrical portion, the heating means moves the cylindrical portion to the cylindrical portion. An on-off valve for vacuum, characterized in that the supplied heat is efficiently transferred to the flat surface. 5. The vacuum on-off valve according to claim 1 or 2, wherein the valve body has a cylindrical portion and a flat portion integrally formed with a cylindrical hole for an input port or an output port. An on-off valve for vacuum that is characterized.