JPH07201759A - Valve device with emergency shutting-off function for reduced pressure heat-treating furnace - Google Patents

Abstract

PURPOSE:To dispense with an air drive type emergency shutting-off valve, which is capable of shutting off instantaneously the exhaust system of a reduce pressure heat-treating furnace at the time of emergency while being a pressure control valve, and to contrive the reduction in facility cost and the space for facilities and the reduction in a piping resistance. CONSTITUTION:In a valve device 20 which is provided in an exhaust system of a vacuum heat-treating furnace, a seating, a valve disc 28 which is seated and separated, and an energizing means 33 to energize this valve disc 28 in the direction of an opened valve are provided by a valve stem 32 made to penetrate hermetically a valve chamber 26 to a valve seat 27 in the chamber 26. Moreover, a coupling releasing mechanism 37, which couples the stem 32 with a drive part 36 and releases the coupling at the time of emergency, is provided between the drive part 36, which opens and shuts and drives the valve body 28 against the energizing force of this means 33 via the valve stem 32, and the valve stem 36. Thereby, the exhaust system of the furnace is instantaneously shut off at the time of emergency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve device with an emergency shutoff function for a reduced pressure heat treatment furnace.

[0002]

2. Description of the Related Art As a low pressure heat treatment furnace, a low pressure CVD (Chemic
There is known a reduced pressure heat treatment furnace used for treatment such as al Vaper Deposition). A processing gas supply system for supplying a processing gas into the furnace and an exhaust system equipped with a decompression pump and a valve device for exhausting and depressurizing the inside of the furnace are connected to the reduced pressure heat treatment furnace. Is configured to be controlled.

In such a decompression heat treatment furnace, the decompression pump is stopped in an emergency such as a sudden power failure during the operation or an emergency such as turning off the power to stop the operation due to an abnormal situation. It is necessary to immediately close the valve device so that the inside of the furnace and the semiconductor wafer are not contaminated by the backflow of the exhaust gas into the furnace under reduced pressure through the exhaust system.

[0004]

However, since the valve device for the exhaust system of the reduced pressure heat treatment furnace is of the manual type or generally driven by an electric motor,
Even if an auxiliary power source is used, it takes time to close the valve,
It was difficult to instantaneously shut off the exhaust system in an emergency. For this reason, it is necessary to provide an air-driven emergency shutoff valve in addition to the valve device in the exhaust system, which causes a problem that an increase in equipment cost and equipment space and an increase in piping resistance are unavoidable.

Therefore, an object of the present invention is to provide a pressure control valve that can instantaneously shut off the exhaust system of the decompression heat treatment furnace in an emergency, eliminating the need for an air-driven emergency shutoff valve, thus reducing equipment costs and equipment space. It is an object of the present invention to provide a valve device with an emergency shut-off function for a decompression heat treatment furnace, which can reduce the fuel consumption and the piping resistance.

[0006]

In order to achieve the above object, the invention of claim 1 is a valve device provided in an exhaust system of a reduced pressure heat treatment furnace, wherein the valve chamber is airtight with respect to a valve seat in the valve chamber. A valve element that is seated and moved away from and away by a valve rod that penetrates the valve body, biasing means that biases the valve element in the valve closing direction, and the valve element that pushes the valve element against the biasing force of the biasing means. A drive unit that is opened and closed via a drive mechanism, and a connection release mechanism that is provided between the drive unit and the valve rod to connect the valve rod and the drive unit and release the connection in an emergency. And

The invention according to claim 2 is based on the invention according to claim 1, wherein the decoupling mechanism slidably inserts the valve rod and moves in the axial direction thereof, and the valve. The lock pin engaging hole formed straddling the rod and the lock pin engaging holes are engaged with the lock pin, so that the lock pin is engaged in the non-energization state in an emergency, thereby engaging the lock pin with the both lock pin. It is characterized in that it is composed of a solenoid that is detached from the hole.

Further, the invention of claim 3 is based on the invention of claim 1, and the end portion of the valve rod is provided at the drive portion which faces the end portion of the valve rod and moves in the axial direction thereof. Adsorb,
It is characterized in that it is composed of an electromagnet that releases the end portion of the valve rod by being de-energized in an emergency.

[0009]

According to the first aspect of the present invention, the valve body is opened and closed by the drive section through the valve rod against the urging force of the urging means.
In the event of an emergency, the connection release mechanism disconnects the connection between the drive unit and the valve rod, and the valve body is automatically and quickly closed by the biasing means. The exhaust system of the heat treatment furnace can be shut off instantly. Therefore, since it is not necessary to provide an air-driven emergency shutoff valve in the exhaust system, the facility cost and the facility space can be reduced, and the pipe resistance of the exhaust system can be reduced to improve the operation efficiency.

According to the second aspect of the present invention, since the valve rod is coupled to the drive unit via the lock pin, the valve rod is integrally linked with the drive unit, and in an emergency, the lock pin is pulled out by the solenoid. When it is removed, the connection between the valve stem and the drive unit will be released, so the drive force can be reliably transmitted from the drive unit to the valve stem in normal times, and the valve stem can be quickly disconnected from the drive unit in an emergency. You can

According to the third aspect of the present invention, since the end portion of the valve rod is adsorbed and coupled to the electromagnet of the drive unit, the valve rod is integrally linked with the drive unit, and the electromagnet is de-energized in an emergency. Since the end of the valve rod is released, the drive force can be reliably transmitted from the drive unit to the valve rod in normal times, and the valve rod can be quickly separated from the drive unit in an emergency. Simplification and reduction of manufacturing cost can be achieved.

[0012]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. First, a decompression heat treatment furnace to which the valve device with an emergency shutoff function of the present embodiment is applied will be described. As shown in FIG. 2, the low-pressure heat treatment furnace 1 is a vertical furnace configured to be suitable for performing a film formation process by low-pressure CVD on a semiconductor wafer W that is an object to be processed, and has a circular opening in the center. 2a
The base plate 2 made of, for example, stainless steel having the above is horizontally provided.

A short tubular manifold 3 made of, for example, stainless steel, having a flange portion 3a at the upper end, is detachably attached to the lower portion of the base plate 2 by bolting so as to align the axis with the opening portion 2a. A reaction tube 4 made of a heat-resistant material such as quartz is provided as the processing furnace 1 on the manifold 3. This reaction tube 4
Has a double pipe structure in which an inner pipe 5 whose upper and lower ends are open and an outer pipe 6 which is closed at its upper end and has an outwardly facing flange 6a are concentrically arranged.

The outer pipe 6 is hermetically supported on the upper end flange portion 3a of the manifold 3 through an O-ring 7 made of a material having heat resistance and corrosion resistance, such as fluorine rubber, as a sealing means. Is supported by a small-diameter step portion 3b formed in the inner periphery of the manifold 3 at a substantially middle portion in the height direction. An inlet port 8 to which a processing gas supply system for communicating the inside of the inner tube 5 with the outside (outside the furnace) and introducing a processing gas from a processing gas supply source (not shown) into the reaction tube 4 is connected to the manifold 3. And an outlet port 9 connected to an exhaust system 18 described later for communicating the annular space 4a between the inner pipe 5 and the outer pipe 6 with the outside (outside the furnace) to exhaust and depressurize the inside of the reaction pipe 4. Is provided.

Around the reaction tube 4, there is arranged a heating section 11 formed by forming a heating wire 10 such as a kanthal wire in a coil shape for heating the inside of the reaction tube 4 to a high temperature, for example, about 800 to 1200 ° C. The outer circumference of the heating portion 11 is covered with an outer shell (not shown) via a heat insulating material 12. The heating unit 11, the heat insulating material 12, and the outer shell are supported on the base plate 2.

Below the manifold 3, a lid 13 made of, for example, stainless steel, which opens and closes the lower surface opening thereof, is provided so as to be able to move up and down by an elevating mechanism 14. On this lid 13, a large number of semiconductors, for example, about 150 semiconductors are provided. Wafer boats 15 that hold the wafers W in a horizontal state in multiple stages at intervals in the vertical direction are mounted via a heat insulating cylinder 16. It should be noted that the lid 13 is provided with a rotation mechanism 17 that rotationally drives the heat retaining cylinder 16.

On the other hand, the exhaust system 18 is composed of a stainless steel pipe 19 having a predetermined pipe diameter of, for example, about 80 mm, and a valve device 20 with an emergency shutoff function and a pressure reducing pump 21 are provided in this pipe 19 in order. There is. Also, the pipe 1
9, a pressure sensor 22 is provided on the upstream side of the valve device 20. The controller 23 controls the emergency shutoff function valve device 20 by feeding back a detection value of the pressure sensor 22. . The pressure sensor 22 in the illustrated example is composed of two sensors having different detection ranges, for example, for 0-10 Torr and for 0-1000 Torr, but only one if it can accurately detect a wide range of pressure. Good.

As shown in FIG. 1, the valve device 20 has a so-called angle valve-shaped valve chamber (casing) 26 having an inlet 24 at the lower end and an outlet 25 at the side, and in the valve chamber 26. Is formed with a flat valve seat 27 which is expanded radially outward at the inner part of the inlet 24, and a valve body 28 is provided so as to be seated with respect to the valve seat 27 and capable of separating and moving in the vertical direction. ing. The valve chamber 26 and the valve body 28 are both made of a material having heat resistance and corrosion resistance, for example, stainless steel, and a portion of the valve body 28 that is seated on the valve seat 27 is an O-ring 29 made of, for example, fluorocarbon rubber as a sealing means. Is provided.

The valve body 28 is formed in a plane circular shape, and a convex portion 30 having a circular cross section which is inserted into the inner periphery of the valve seat 27 is formed in the lower portion thereof, and the outer peripheral wall portion 30a of the convex portion 30 and the valve portion 30a. A fine adjustment gap 31 is formed between the seat 27 and the inner peripheral wall portion 27a to enable weak pressure reduction control. The conductance of the vacuum pressure in the fine adjustment gap 31 is equal to the gap 31.
By utilizing the fact that the valve body 28 is moved within the length range of the gap 31 by utilizing the fact that it is in proportion to the cross-sectional area of the gap 31 and is inversely proportional to the length of the gap 31, the weak pressure reduction control is performed, for example, 300 to 760 Torr. It is possible within a certain range. Further, the maximum opening position (about 2/3 from below in the valve chamber 26) from the position of the valve body 28 where the cross-sectional area between the valve body 28 and the valve seat 27 exceeds the cross-sectional area of the fine adjustment gap 37. By adjusting the movement of the valve body up to the (position), pressure control from medium pressure reduction to strong pressure reduction is performed, and it is possible to reduce the pressure to about 3 × 10 ⁻³ Torr at the maximum opening, depending on the capacity of the pressure reduction pump 21. Has become.

A valve rod 32 is provided upright at the center of the upper portion of the valve body 28, and an upper end portion of the valve rod 32 extends through the upper portion of the valve chamber 26 to the outside. A coil spring 33 is provided between the valve body 28 and the upper end of the valve chamber 26 as a biasing means for biasing the valve body 28 on the valve seat 27 in a valve closing direction.
Is inserted so as to insert the valve rod 32 inside, and the valve rod 32 and the coil spring 33 are covered between the upper end of the valve body 28 and the upper end of the valve chamber 26 to cover the valve. Body 2
A bellows 34 made of stainless steel is interposed by welding as means for sealing the penetrating portion of the valve rod 32 while allowing the movement of the valve 8. A bearing 35 that supports the valve rod 32 movably in the axial direction is provided above the valve chamber 26.

A valve rod 32 extending from the valve chamber 26 to the outside
The valve element 28 against the biasing force of the coil spring 33.
A drive unit 36 for opening and closing the valve rod 32 is connected, and the drive rod 36 and the valve rod 32 are connected to each other and the connection is released in an emergency. A connection releasing mechanism 37 is provided. The drive portion 36 is provided with a screw shaft 39 of, for example, a ball screw, which is provided in parallel with the valve rod 32 via a bearing 38 on a fixed portion such as the outer wall of the valve chamber 26, and one end of the screw shaft 39 is provided at one end thereof. A pulse motor 43, which is an electric motor, is connected via the toothed pulleys 40, 41 and the toothed belt 42.

The screw shaft 39 is provided with an output arm portion 44, which is operated to move along the axial direction of the valve rod 32 by its rotation, via a nut 45. The valve arm 32 is attached to the output arm portion 44. A shaft hole 47 is formed so as to be axially movably inserted through the bearing 46. Then, the output arm portion 44
The valve rod 32 and the valve rod 32 have a substantially conical lock pin engaging hole for engaging the lock pin 48 having a substantially conical shape as the disconnecting mechanism 37 across the output arm portion 44 and the valve rod 32. 49 and 50 are formed in the radial direction, and the output arm portion 44 is provided with a solenoid 51 for disengaging the lock pin 48 from the lock pin engagement holes 49 and 50 when it is not excited in an emergency.

The solenoid 51 has a drive shaft 52 that extends horizontally through the solenoid 51, and a lock pin 48 is provided at one end of the drive shaft 52 so as to face the lock pin engagement hole 49 on the output arm 44 side. A coil spring 53 is attached to the other end of the drive shaft 52 to urge the lock pin 48 away from the lock pin engagement hole 49. In the energized and excited state, the solenoid 51 is held at the lock position where the lock pin 48 is engaged with the lock pin engagement holes 49 and 50 against the biasing force of the coil spring 53 as shown in FIG. When the power is turned off due to a power failure or an abnormal situation, the lock pin 48 is de-energized in an emergency such that the lock pin 48 is disengaged from the lock pin engagement holes 49 and 50 by the urging force of the coil spring 53. Is configured to.

Next, the operation of the above embodiment will be described. First, nitrogen gas is introduced from the inlet port 8 and the outlet port 9
The inside of the reaction tube 4 of the reduced pressure heat treatment furnace 1 by replacing the inside of the reaction tube 4 with nitrogen gas by exhausting the gas through the exhaust system 18.
And the wafer boat 15 supporting the semiconductor wafer W is loaded into the reaction tube 4 together with the heat insulation cylinder 16.

Next, with the valve of the processing gas supply system of the inlet port 8 closed, the reaction tube 4 is evacuated and decompressed through the exhaust system 18 to perform vacuum replacement. At this time, in order to prevent the particles from being wound up, first, the valve body 28 of the valve device 20 is slightly opened from the closed position, and the slow vacuum is performed through the fine adjustment gap 31 until it becomes, for example, about 10 Torr, and then, The valve body 28 is fully opened and the inside of the reaction tube 4 is vacuum-replaced at, for example, about 0.5 Torr.

When the vacuum replacement is completed, the valve body 28 is once closed, and in this state the valve of the processing gas supply system is gradually opened to introduce the processing gas into the reaction tube 4, whereby the inside of the reaction tube 4 is introduced. When the pressure reaches the processing pressure, for example, about 400 Torr, the valve body 28 is opened, and the inside of the reaction tube 4 is maintained at the processing pressure by weak pressure reduction control through the minute adjustment gap 31.
When the processing of the semiconductor wafer W is completed, the inside of the reaction tube 4 is evacuated and replaced with nitrogen gas in the reverse order to return the inside of the reaction tube 4 to the normal pressure, and then the lid 13 is placed.
The wafer boat 15 may be carried out from the inside of the reaction tube 4 while opening downward.

In controlling the valve element 28 as described above, the controller 23 controls the pulse motor 43 of the driving section 36, and the output arm section 44, which is moved by the rotation of the screw shaft 39, is locked via the lock pin 48. The valve stem 32 is integrally linked with each other. By the way, the valve body 2
When an emergency situation occurs, such as when the power is turned off and the operation is forcibly stopped due to a power failure or an abnormality in the operating state in which the valve 8 is opened, the solenoid 51 of the disconnecting mechanism 37 is de-energized, and the lock position Of the lock pin 48 by the biasing force of the coil spring 53.
Being separated from 50. This causes the valve rod 32 to move the output arm 4
4 is free, so that the valve body 28 has the coil spring 33.
The valve is closed by the urging force of the
Is cut off instantly.

As described above, according to the valve device 20 with the emergency shut-off function, the valve body 28 is opened and closed by the drive unit 36 through the valve rod 32 against the urging force of the coil spring 33 which is the urging means. Sometimes the connection releasing mechanism 37 causes the drive unit 3 to operate.
Since the connection between 6 and the valve rod 32 is released and the valve body 28 is automatically and quickly closed by the coil spring 33, the exhaust system 18 of the decompression heat treatment furnace 1 is a pressure control valve in an emergency. Can be shut off instantly. Therefore, it is not necessary to provide an air-driven emergency shutoff valve in the exhaust system 18, so that the equipment cost and the equipment space can be reduced, and the piping resistance of the exhaust system 18 can be reduced to dramatically improve the operating efficiency. Can be improved.

Further, according to the connection releasing mechanism 37 of the embodiment, the valve rod 32 is coupled to the drive portion 36 via the lock pin 48, so that the valve rod 32 is integrally linked with the drive portion 36, In an emergency, the lock pin 48 is pulled out by the solenoid 51 to release the coupling between the valve rod 32 and the drive unit 36. Therefore, the drive force from the drive unit 36 to the valve rod 32 is ensured in normal times. The valve rod 32 can be transmitted and the valve rod 32 can be quickly separated from the drive unit 36 in an emergency, and the highly reliable valve device 20 with an emergency shutoff function can be obtained.

FIG. 4 shows another embodiment of the valve device with an emergency shut-off function for the reduced pressure heat treatment furnace. In this embodiment, the internal structure of the valve chamber and the structure of the drive unit are almost the same as those in the above-mentioned embodiment, and the same parts as those in the above-mentioned embodiment are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, the connection release mechanism 37
As for the electromagnet 54, an upper end of the valve rod 32 is attracted and the upper end of the valve rod 32 is released by being de-energized in an emergency.

The electromagnet 54 is provided on the output arm portion 44 of the drive unit 36 so as to face the upper end of the valve rod 32, and the upper end of the valve rod 32 is attracted to the electromagnet 54 when energized. An attracted portion 55 made of a magnetic material is formed on the surface. Further, the output arm portion 44 is supported by the guide 56 so as to be movable along the axial direction of the valve rod 32 in order to align the electromagnet 54 with the axial center of the valve rod 32.
A conical protrusion 57 is formed on the lower end of the valve rod, and a conical recess 58 with which the protrusion 57 is engaged is formed on the attracted portion 55 that is the upper end of the valve rod 32.

The valve device 2 of this embodiment having the above structure
According to 0, the upper end of the valve rod 32 is adsorbed and coupled to the electromagnet 54 in the energized state of the drive unit 36, so that the valve rod 32 is integrally linked with the drive unit 36 and is de-energized in an emergency. Since the upper end portion of the valve rod 32 is released from the electromagnet 54, the driving force can be reliably transmitted from the drive unit 36 to the valve rod 32 in the normal state, and the drive unit 36 can drive the valve rod 3 in an emergency.
2 can be quickly separated, and the same effect as the above embodiment can be obtained. In addition, the connection release mechanism 37 is connected to the valve rod 32.
Since it is composed of the electromagnet 54 that directly attracts the upper end portion of, the structure can be simplified and the manufacturing cost can be reduced.

The present invention is not limited to the above embodiment, but various modifications can be made within the scope of the gist of the present invention. For example, in the embodiment of FIG. 4, the structure is such that the upper end portion of the valve rod 32 extending from the valve chamber 26 is adsorbed by the electromagnet 54. However, for example, the valve rod 32 in the valve chamber 26 is provided with a valve on the valve body 28 side. It is divided into a rod and a valve rod on the drive side directly connected to the output arm portion 44 of the drive unit 36, and an electromagnet for adsorbing the upper end of the valve rod on the valve body side is provided at the lower end of the valve rod on the drive side. It may have a structure (not shown).

As the biasing means for biasing the valve element 28 in the valve closing direction, a fluid pressure cylinder such as air pressure or hydraulic pressure, an air cushion or the like can be applied in addition to the coil spring, and the accumulated air pressure is used. It is more preferable that the air cylinder and the air cushion are not affected by the power failure. In this case, for example, an air cylinder or an air cushion may be provided at the upper end of the valve chamber 26 so as to urge the valve rod 32 in the valve closing direction. Furthermore, the reduced-pressure heat treatment furnace 1 may not have the inner tube 5, and may be one that can perform processes such as oxidation, diffusion, and annealing in addition to the reduced-pressure CVD.

[0035]

In summary, according to the present invention, the following excellent effects can be obtained.

(1) According to the first aspect of the present invention, the valve element is seated and separated from the valve seat in the valve chamber by the valve rod that hermetically penetrates the valve chamber, and the valve element is closed in the valve closing direction. An urging means for urging the urging means, a drive section for opening and closing the valve body through the valve rod against the urging force of the urging means, and a drive section provided between the drive section and the valve rod. Since it has a connection release mechanism that connects the valve stem and the drive unit and releases the connection in an emergency, the exhaust system of the reduced pressure heat treatment furnace can be instantaneously shut off in an emergency even though it is a pressure control valve. Since it is not necessary to provide an air-driven emergency shutoff valve in the exhaust system, the equipment cost and the equipment space can be reduced, and the piping resistance of the exhaust system can be reduced to improve the operation efficiency.

(2) According to the invention of claim 2, the connection releasing mechanism straddles the drive rod and the valve rod that slidably pass through the valve rod and move in the axial direction thereof. And a solenoid for engaging the lock pins into the lock pin engagement holes and disengaging the lock pins from the lock pin engagement holes by de-energizing in an emergency. The drive force can be reliably transmitted from the drive unit to the valve rod during normal operation, and the valve rod can be quickly separated from the drive unit during an emergency.

(3) According to the third aspect of the present invention, the end portion of the valve rod is attached to the drive unit which is opposed to the end portion of the valve rod and moves in the axial direction thereof, and the end portion of the valve rod is sucked to prevent non-operation in an emergency. Since it is composed of an electromagnet that releases the end of the valve rod when energized, the drive force can be reliably transmitted from the drive unit to the valve rod during normal operation, and the valve rod can be quickly disconnected from the drive unit in an emergency. In addition, the structure can be simplified and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional side view of essential parts showing an embodiment of a valve device with an emergency shutoff function for a reduced pressure heat treatment furnace according to the present invention.

FIG. 2 is a cross-sectional view showing an example of a reduced pressure heat treatment furnace.

FIG. 3 is a partial cross-sectional side view showing a state in which the lock pin of the valve device of FIG. 1 is engaged with the lock pin engagement hole.

FIG. 4 is a partial side view showing another embodiment of the valve device with an emergency shutoff function for the reduced pressure heat treatment furnace.

[Explanation of symbols]

 1 Decompression heat treatment furnace 18 Exhaust system 20 Valve device with emergency shutoff function 26 Valve chamber 27 Valve seat 28 Valve body 32 Valve rod 33 Coil spring (biasing means) 36 Drive part 37 Connection release mechanism 48 Lock pin 49, 50 Lock pin engagement Hole 51 solenoid 54 electromagnet

Front page continued (72) Inventor Hironobu Nishi 1-2-1 41 Machiya, Shiroyama-cho, Tsukui Group, Kanagawa Prefecture, Tokyo Electron Tohoku Co., Ltd. Sagami Business Office

Claims (3)

[Claims] 1. A valve device provided in an exhaust system of a decompression heat treatment furnace, the valve body being seated and separated from a valve seat in the valve chamber by a valve rod that hermetically penetrates the valve chamber, and the valve. An urging means for urging the body in the valve closing direction; a drive section for opening and closing the valve body via the valve rod against the urging force of the urging means; and the drive section and the valve rod. A valve device with an emergency cutoff function for a reduced pressure heat treatment furnace, comprising: a valve release mechanism provided between the valve rod and the drive unit and disconnecting the valve connection in an emergency. 2. A lock pin engaging hole formed across the drive portion and the valve rod, wherein the decoupling mechanism slidably passes through the valve rod and moves in the axial direction thereof. And a solenoid that engages the lock pins with the lock pin engagement holes and de-energizes the lock pins from the lock pin engagement holes in an emergency. The valve device with an emergency shutoff function for a reduced pressure heat treatment furnace according to claim 1. 3. The decoupling mechanism is provided in the drive unit that moves in the axial direction facing the end portion of the valve rod to adsorb the end portion of the valve rod, and to be de-energized in an emergency. 2. The valve device with an emergency shut-off function for a reduced pressure heat treatment furnace according to claim 1, wherein the valve device comprises an electromagnet that releases the end portion of the valve rod.