JP3946405B2 - Vacuum piping structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vacuum piping structure, and more particularly to a vacuum piping structure disposed for evacuation of a single crystal manufacturing apparatus such as silicon for semiconductors.
[0002]
[Prior art]
Various methods have already been proposed and implemented as methods for producing a semiconductor single crystal using a crystal material such as silicon. In any of the main methods, the inside of the single crystal production apparatus is evacuated by evacuation. The single crystal is deposited and grown in an atmosphere in which an inert gas such as argon is injected. For this reason, the single crystal manufacturing apparatus is provided with a vacuum pipe line connected to a vacuum pump.
As a method of manufacturing this single crystal, a seed (seed crystal) is immersed in a melt such as high-purity polycrystalline silicon that has been heated and melted, and the single crystal is precipitated and grown by rotating the seed while rotating it. The Czochralski method (hereinafter referred to as CZ method) for obtaining a single crystal ingot is a common method.
FIG. 4 schematically shows a conventional example of a single crystal pulling apparatus used for manufacturing a single crystal by the CZ method and its vacuum piping structure.
The single crystal pulling apparatus is constructed by stacking and assembling a bearing mechanism 3 and a hoisting mechanism 4 sequentially from a lower part in a furnace body composed of a main chamber 1 and a pull chamber 2, and is melted at a high temperature in a crucible 11 of the main chamber 1. The seed 17 attached to the seed holder 16 at the lower end of the wire 15 suspended from the upper winding mechanism 4 is immersed in the silicon melt 12 to rotate the crucible 11 and the winding mechanism to rotate the wire 15 and the seed holder. A single crystal 18 of silicon is deposited by pulling up the seed 17 at a low speed while rotating 16.
This single crystal pulling operation is performed by evacuating the inside of the apparatus by the pipe 8 provided in the vacuum pump 10 from the base of the main chamber 1 as described above, and injecting an inert gas such as argon into the apparatus. (In FIG. 5, the gas injection path to the apparatus is omitted).
[0003]
[Problems to be solved by the invention]
As described above, the pipe line 8 provided in the illustrated single crystal pulling apparatus is used as an atmospheric flow path for depressurizing the inside of the apparatus by evacuation. It is also used as a conduit for discharging the active gas and discharging the vapor of the crystal raw material generated in the apparatus by this gas flow.
This is intended to simplify piping design as much as possible, to make piping and maintenance convenient, and to respond economically, but as a result, the discharge flow rate of inert gas is adjusted to the pipeline 8 in the device. The butterfly valve 81, which is a flow rate adjusting valve for controlling the gas pressure, is provided.
However, the butterfly valve 81 forms a flow path whose diameter is greatly reduced as compared with other pipes 83 constituting the pipe line 8, and is a large flow path obstruction for vacuuming that does not require flow rate adjustment. It becomes.
Of course, the above problem itself can be solved by providing the apparatus with a vacuum line without a butterfly valve and an inert gas discharge line with a butterfly valve. However, in the case of adopting such a pipe configuration, the piping facility and maintenance management are extremely complicated, and the cost must be greatly increased, which cannot be said as a practical problem solving method.
[0004]
In addition, as already mentioned above, the inert gas is injected into the single crystal manufacturing apparatus from the upper part of the apparatus and discharged from the melt 12 and the crucible made of quartz. This is for discharging SiOX (hereinafter abbreviated as “vapor”) 11 generated by the reaction of 11 to the outside of the apparatus, and this vapor adheres to the entire pipe 8 which is a gas flow path, and it takes a great deal of time to remove it. I need it.
A vapor is inevitably generated in the operation of pulling a single crystal, and when it adheres to and condenses on the surface of the silicon single crystal in the device or the inner wall of the device and drops onto the silicon melt, it dislocations into the growing single crystal Cause product yield to deteriorate. For this reason, it must be discharged out of the apparatus together with a high purity inert gas injected into the apparatus.
Since this vapor adheres in powder form to the entire pipeline 8 forming the discharge path, and the performance of the vacuum pump 10 is deteriorated, measures such as providing a dust filter on the pipeline 8 are taken. However, there is a limit to the collection by the dust filter, and a proposal of a method for reducing the discharge amount of the vapor to the entire pipe line 8 and the vacuum pump 10 is desired.
[0005]
The present invention has been made in view of such a problem, and an object of the present invention is to perform evacuation in a short time without being obstructed by a flow path of a butterfly valve provided in a pipe line in the production of a single crystal. Therefore, it is an object of the present invention to provide a vacuum piping structure capable of efficiently collecting and removing the vapor discharged from the apparatus by the inert gas.
[0006]
[Means for Solving the Problems]
In order to solve this problem and achieve the object, the present invention has the following configurations. The invention described in claim 1 is connected to a vacuum pipe arranged to depressurize a semiconductor single crystal manufacturing apparatus by a flow rate adjusting valve for adjusting a discharge amount of an inert gas injected into the apparatus. A bypass line having an opening / closing valve is provided in the pipe line, a bent part is formed in the pipe line in the vicinity of the device, an opening having an openable / closable door is provided in the bent part, and the bent part is provided in the bent part. A cooling means is additionally provided.
By configuring in this way, a bypass line having an opening / closing valve is formed with respect to the line connected by the flow rate adjusting valve, and an opening / closing valve having a low flow resistance is provided when the pressure in the apparatus is reduced. When the inert gas is discharged, a pipeline having a flow rate adjusting valve for adjusting the discharge flow rate is used. Further, the Vepa discharged from the apparatus, and removed from the opening by attaching the conduit bent portion of the apparatus near reduces the functional deterioration of the adhesion and the vacuum pump to the entire vacuum pipe conduit, conduit device near The vapor is intentionally attached to the pool portion provided in the bent portion and accumulated.
The invention described in claim 2 is connected by a flow rate adjusting valve for adjusting a discharge amount of an inert gas injected into the apparatus in a vacuum pipe arranged to depressurize the semiconductor single crystal manufacturing apparatus. A bypass line provided with an open / close valve is provided in the pipe line, a bent part is formed in the pipe line in the vicinity of the device, and a reservoir part having an opening with an openable / closable door is provided in the bent part,
And annexed to the cooling means to the bending portion, characterized in that.
By comprising in this way, the vapor | steam of the crystal raw material which should be removed is made to adhere efficiently to the pipe line bending part and pool part of an apparatus vicinity.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a vacuum piping structure according to the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory view schematically showing a schematic configuration of a vacuum piping structure of a single crystal device according to an embodiment, FIG. 2 is a partially enlarged view of a bent portion of a pipe line, and FIG. 3 according to another embodiment. It is the elements on larger scale of a pipe line bending part.
The single crystal manufacturing apparatus shown in FIG. 1 is a single crystal pulling apparatus using the CZ method as in the conventional example. A vacuum pipe line 8 is provided from the base of the main chamber 1 provided with the crucible 11 to the vacuum pump 10. ing.
The pipe line 8 is not only used for evacuating and depressurizing the inside of the apparatus, but also discharges the inert gas injected into the apparatus, thereby discharging the vapor generated in the apparatus to the outside. It is also used for this purpose.
For this reason, the pipe line 8 is also provided with a butterfly valve 81 for adjusting the discharge flow rate of the inert gas.
[0008]
In the illustrated piping structure, one of the differences from the conventional example is that a bypass line 9 having an opening / closing valve 91 is formed with respect to a line 8 connected by a butterfly valve 81 as shown in FIG. There is.
When comparing the pipes 8 and 9, the flow path of the pipe 8 connected by the butterfly valve 81 is greatly reduced in diameter and narrowed at the butterfly valve 81 portion. The bypass pipe line 9 connected by the valve 91 is almost the same as the pipe diameter of the basic pipe 83 constituting the pipe line 8 including the flow path of the opening / closing valve 91 itself.
[0009]
Next, as shown in FIGS. 1 and 2, in the illustrated piping structure, a substantially right angle is formed on the pipe line immediately below the single crystal manufacturing apparatus so that the vapor discharged from the apparatus is easily attached. The bent portion 84 is formed, and an opening 85 provided with a flange is provided on the front side of the open side of the bent portion 84 so as to remove the paper, and a door 86 having the same diameter as the outer diameter of the flange is easily mounted. Yes.
In addition, a water jacket 88 is attached to the bent portion 84 provided with the opening 85 as described above, and cooling water serving as a coolant is supplied to the water jacket 88 via the water pipe 89 to cool the pipe bent portion 84. It is configured to perform processing.
The inner surface of the bent portion 84 exposed from the opening 85 by opening the door 86 was coated with a fluororesin.
[0010]
FIG. 3 shows a bent portion 84 of the pipe line 8 according to another embodiment. The bent part 84 is formed at a substantially right angle to the pipe line located immediately below the apparatus, and the bent part 84 is opened. In an opening 85 provided on the side front surface, a reservoir portion (vapor collecting portion) 87 having a door 86 that can be opened and closed is continuously provided in a communicating state.
Also in this embodiment, the reservoir 87 is provided with a water jacket 88 having a water pipe 89, and on the inner surface of the bent portion 84 communicating with the entire interior of the reservoir 87 via the opening 85. And coated with fluororesin.
[0011]
The illustrated vacuum piping structure has the above-described configuration, and when vacuuming is performed for depressurization of the single crystal pulling device, the on-off valve 91 of the bypass line 9 is opened to open the inside of the device. Can be discharged through the bypass line 9 having a very low flow resistance, so that the evacuation time is shorter than that in the conventional example in which the evacuation is performed using only the line 8 provided with the butterfly valve. And the workability of single crystal production can be greatly improved.
Further, if the opening / closing valve 91 of the bypass line 9 is closed after the evacuation is completed, the argon gas injected into the apparatus and the vapor generated in the apparatus are only the line 8 connected by the butterfly valve 81. The gas is discharged through the gas, and there is no problem in adjusting the flow rate and controlling the gas pressure.
[0012]
In the embodiment shown in FIGS. 1 and 2, a bent portion 84 having a substantially right angle is provided for the purpose of attaching a vapor to a pipe line located immediately below the single crystal manufacturing apparatus. Since the opening 85 provided with the door 86 which can be opened and closed is provided on the front side of the open side of the 84, the paper attached to the inside of the bent portion 84 can be easily and easily removed by opening the door 86.
For this reason, the vapor generated and discharged in the apparatus can be effectively removed at the start end portion of the pipe line 8 immediately after the discharge, adheres to the entire pipe line 8 following this, or deteriorates the performance of the vacuum pump 10. The amount of vapor discharged can be reduced.
In addition, in the illustrated embodiment, since the water jacket 88 is attached to the bent portion 84 to which the water is attached, the vapor is cooled and condensed by the bent portion 84, and the amount of adhesion to the bent portion 84 is reduced. It can be increased effectively.
Further, the inner surface of the bent portion 84 is coated with a fluororesin to facilitate removal of the attached vapor.
[0013]
In the embodiment shown in FIG. 3, a reservoir 87 having a door 86 that can be opened and closed is connected to an opening 85 provided in the bent portion 84 of the conduit 8 in a communicating state, and a water jacket 88 is provided in the reservoir. Since it is attached, the vapor can be attached and removed more efficiently at the pipe start end. [0014]
【The invention's effect】
Since this invention is comprised as mentioned above, there exists an effect hung up below.
(1) According to the invention described in claim 1, since the bypass line connected by the open / close valve is formed with respect to the line connected by the butterfly valve, when depressurizing the inside of the apparatus, By using a bypass line with low flow resistance, evacuation can be performed in a short time to improve workability, and a cooling means is attached to the bent portion provided at the pipe start end near the single crystal manufacturing apparatus. Then, the vapor is cooled and condensed, and the vapor of the crystal raw material is adhered and removed, so that the discharge amount to the entire vacuum pipe line can be reduced and the performance deterioration of the vacuum pump due to the vapor can be prevented. .
(2) According to the invention described in claim 2 , since the reservoir is provided in the bent portion to which the vapor is adhered, and the cooling means is attached to the reservoir, the vapor is cooled and condensed, and the vapor is added to the reservoir. Can be integrated and removed efficiently .
[Brief description of the drawings]
FIG. 1 is an explanatory view schematically showing a schematic configuration of a vacuum piping structure of an apparatus according to an embodiment.
FIG. 2 is a partially cutaway explanatory view showing a configuration of a pipeline bending portion in the embodiment.
FIG. 3 is a partially cutaway explanatory view showing a configuration of a conduit bending portion in another embodiment.
FIG. 4 is an explanatory view schematically showing a schematic configuration of a vacuum piping structure of a conventional apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Main chamber 2 Pull chamber 3 Bearing mechanism 4 Winding mechanism 8 Main pipe line 9 Bypass pipe line 10 Vacuum pump 11 Crucible 12 Silicon melt 15 Wire 16 Seed holder 17 Seed 18 Single crystal 81 Butterfly valve 83, 93 Pipe 84 Bent part 85 Opening 86 Door 87 Reservoir 88 Water jacket 89 Water pipe 91 Open / close valve

Claims (2)

In vacuum piping arranged to depressurize the manufacturing equipment for semiconductor single crystals,
In a pipeline connected by a flow rate adjusting valve that adjusts the discharge amount of the inert gas injected into the apparatus,
A bypass line with an open / close valve is provided ,
While forming a bent portion in the conduit near the device,
An opening with an openable / closable door is provided in the bent portion,
And a cooling means is attached to the bent portion,
A vacuum piping structure characterized by that. In vacuum piping arranged to depressurize the manufacturing equipment for semiconductor single crystals,
In a pipeline connected by a flow rate adjusting valve that adjusts the discharge amount of the inert gas injected into the apparatus,
A bypass line with an open / close valve is provided ,
While forming a bent portion in the conduit near the device,
A pool part having an opening with an openable / closable door is provided in the bent part,
And a cooling means is attached to the bent portion,
A vacuum piping structure characterized by that.

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