JP4775343B2 - Quartz crucible and polycrystalline silicon recovery method and apparatus - Google Patents

Description

  The present invention relates to a method for recovering polycrystalline silicon in which a quartz crucible after pulling a single crystal and a molten metal remaining in a melt are cooled and solidified in the Czochralski method, and a recovery apparatus therefor.

  A single crystal used as a substrate of a semiconductor device such as a memory or a CPU is, for example, a silicon single crystal, and is mainly manufactured by the Czochralski method (hereinafter abbreviated as CZ method).

  When a single crystal is manufactured by the CZ method, it is manufactured using a single crystal manufacturing apparatus as shown in FIG. This single crystal manufacturing apparatus has a member for accommodating and melting the raw material polycrystal, a heat insulating member for blocking heat, and the like, which are accommodated in the main chamber 21. A pulling chamber 22 extending upward from the ceiling of the main chamber 21 is connected, and a mechanism (not shown) for pulling up the single crystal 23 with a wire 33 is provided on the upper portion.

  In the main chamber 21, a quartz crucible 25 for containing the raw material melt 24 and a graphite crucible 26 for supporting the quartz crucible 25 are provided. It is supported. The driving mechanism of the crucibles 25 and 26 raises the crucibles 25 and 26 by the amount corresponding to the liquid level drop in order to compensate for the liquid level drop of the raw material melt 24 accompanying the pulling of the single crystal 23.

  And the heater 27 for melting a raw material is arrange | positioned so that the crucibles 25 and 26 may be surrounded. In order to prevent heat from the heater 27 from being directly radiated to the main chamber 21, a heat insulating member 28 is provided outside the heater 27 so as to surround the periphery thereof.

  In addition, an inert gas such as argon gas is introduced into the main chamber 21 from a gas inlet 30 provided in the upper portion of the pulling chamber 22. The introduced inert gas passes between the single crystal 23 being pulled up and the gas rectifying cylinder 31 which is a heat shield member, and between the lower part of the heat shield member 32 and the liquid surface of the raw material melt 24. It passes through and is discharged from the gas outlet 29.

  The raw material polycrystal is accommodated in the quartz crucible 25 arranged in the single crystal manufacturing apparatus as described above, and heated by the heater 27 to melt the raw material polycrystal in the quartz crucible 25. In this way, the seed crystal 35 fixed by the seed holder 34 connected to the lower end of the wire 33 is deposited on the raw material melt 24 which is the melt of the raw material polycrystal, and then the seed crystal 35 is rotated. By pulling up, the single crystal 23 having a desired diameter and quality is grown below the seed crystal 35. At this time, after the seed crystal 35 is deposited on the raw material melt 24, the seed crystal 35 is thickened until a desired diameter is obtained, and the dislocation-free crystal is pulled up.

And after pulling up the single crystal of length useful as a product, an unnecessary raw material melt remains in the crucible. The remaining raw material melt is solidified by cooling to room temperature after pulling the single crystal, and remains in the quartz crucible as polycrystalline silicon.
Here, after pulling up the single crystal, the quartz crucible holding the raw material melt and the polycrystalline silicon in which the remaining hot water is hardened cannot be reused and are discarded. However, since the graphite crucible supporting it can be reused, only the quartz crucible supported inside the graphite crucible and the polycrystalline silicon remaining in the quartz crucible are replaced with the graphite crucible. It is necessary to collect and dispose of from the inside.

  Up to now, the quartz crucible was crushed to an appropriate size by the operator's hand, and it was manually removed from the graphite crucible and collected. In addition, the remaining hot water in the quartz crucible increased, that is, the remaining amount of polycrystalline silicon increased, and the burden of recovery increased. Further, in this recovery method, the work of crushing the quartz crucible is not preferable for safety, and there are various problems such as poor workability.

  In order to deal with such a problem, the quartz crucible is separated from the carbon crucible by pressing the bottom of the quartz crucible at about 800 ° C. or higher during the cooling in the decompression chamber after growing the single crystal. There is disclosed a quartz crucible recovery device having a structure in which a support member capable of applying a pressing force over a wide range of the bottom portion of the material is inserted between a carbon crucible and a quartz crucible, and the support member is moved up and down (Patent Document 1). However, it was necessary to take out the high-temperature quartz crucible from the graphite crucible, and there was a great safety disadvantage.

JP 2001-163697 A

  The present invention has been made in view of the above-mentioned problems. A quartz crucible after pulling up a silicon single crystal and polycrystalline silicon remaining in the quartz crucible are replaced with a graphite crucible supporting the quartz crucible. It aims at providing the method and apparatus which collect | recover from it safely and efficiently, without destroying.

  In order to solve the above problems, in the present invention, in the Czochralski method, after the pulling of the silicon single crystal from the silicon melt in the quartz crucible supported by the graphite crucible that can be divided into two parts, A recovery method for recovering from the graphite crucible the polycrystalline silicon solidified by cooling the remaining molten silicon melt, and after the pulling of the silicon single crystal is finished, the quartz crucible and the polycrystalline silicon are The graphite crucible to be supported is placed on a left / right openable / closable table, and the table is mechanically opened to the left and right to open the two-divided graphite crucible to the left and right, and is supported in the graphite crucible. The quartz crucible and the polycrystalline silicon remaining in the quartz crucible are dropped into a recovery container installed under the table, so that the quartz crucible and Providing a quartz crucible and a method for recovering polycrystalline silicon and recovering the polycrystalline silicon (claim 1).

As described above, the graphite crucible to be recovered and the graphite crucible supporting the polycrystalline silicon remaining in the quartz crucible are formed into a structure that can be divided into two parts, and the graphite crucible is placed on a left-right openable table. Then, the quartz crucible and the polycrystalline silicon supported in the graphite crucible are dropped into a collection container placed under the table and collected by mechanically separating the left and right.
Compared to the conventional method in which the quartz crucible is crushed and the polycrystalline silicon inside is manually collected by the operator, the recovery method of the present invention does not require the quartz crucible to be crushed and is very safe. In addition, it is possible to eliminate the trouble of taking out the fragments from the graphite crucible, and this is a recovery method that can greatly reduce the burden on the operator.
Furthermore, since the risk of breaking the graphite crucible can be greatly reduced, it can be easily reused.

  Further, in the present invention, after the silicon single crystal is pulled up from the silicon melt in the quartz crucible supported by the graphite crucible supported by the Czochralski method, the quartz crucible and the remaining melt of the silicon melt are removed. A recovery device for recovering cooled and solidified polycrystalline silicon from within the graphite crucible, comprising at least a left-right openable table, a mechanism for opening and closing the table, the quartz crucible and the polycrystalline silicon And the table is configured to place the graphite crucible that can be divided into two parts, and when the table is mechanically opened to the left and right by the opening and closing mechanism, the graphite crucible Is opened to the left and right, and the quartz crucible supported by the graphite crucible by opening the graphite crucible to the left and right, and A quartz crucible and a polycrystalline silicon recovery device are provided for recovering the polycrystalline silicon remaining in the quartz crucible by dropping it into the recovery container installed under the table. (Claim 2).

  Thus, by utilizing the fact that the graphite crucible supporting the quartz crucible is formed so as to be divided into two parts, the graphite crucible is mechanically separated into left and right, thereby supporting the quartz crucible supported in the graphite crucible. The quartz crucible and the polycrystalline silicon are recovered by dropping the polycrystalline silicon and receiving it in the recovery container. Conventionally, the quartz crucible was crushed and the polycrystalline silicon inside was manually collected by the operator. However, with the recovery device of the present invention, it is not necessary to crush the quartz crucible, so it is very safe. In addition, since it is possible to save the trouble of taking out the fragments from the graphite crucible, the burden on the operator can be greatly reduced, and the recovery efficiency can be greatly improved.

Moreover, it is preferable that the edge of the opening / closing part has an upright claw shape in the left / right opening / closing table.
By placing the graphite crucible on the table so that such standing claws are inserted into the gap between the two-divided graphite crucibles, the graphite crucible can be easily divided into two. Crystalline silicon can be recovered more easily.

The mechanism for opening and closing the table is preferably a manual opening / closing type or an electric opening / closing type.
As described above, the drive source of the mechanism for opening and closing the table can be a manual type or an electric type, and any of them can easily open and close the table, that is, the graphite crucible can be easily divided into two. Quartz crucibles and polycrystalline silicon can be easily recovered.

Moreover, it is preferable that the said collection | recovery apparatus is equipped with the mechanism for transferring the said container to collect | recover (Claim 5).
Since the recovery container after recovering the quartz crucible and the polycrystalline silicon can be very heavy, it is preferable to include a mechanism for transferring the recovery container.

Moreover, it is preferable that the mechanism for transporting includes at least a lifter and / or a conveyor.
Thus, by providing at least a lifter and / or a conveyor as a mechanism for transferring the collection container, the collection container can be transferred smoothly and efficiently.

  As described above, the present invention utilizes the fact that the graphite crucible supporting the quartz crucible can be divided into two parts, and mechanically divides the graphite crucible into two parts to the left and right, thereby supporting the quartz crucible supported there. The polycrystalline silicon in the quartz crucible is dropped, and the quartz crucible and polycrystalline silicon dropped in the collection container are collected. This eliminates the step of crushing the quartz crucible and eliminates the step of crushing the quartz crucible as compared with the conventional method of crushing the quartz crucible and recovering the polycrystalline silicon inside by the operator, so that it can be made very safe. In addition, it is possible to save the trouble of taking out the fragments from the graphite crucible, greatly reduce the burden on the operator, and greatly improve the recovery efficiency. Furthermore, since the risk of breaking the graphite crucible can be greatly reduced, it can be easily reused.

Hereinafter, the present invention will be described more specifically.
As described above, the quartz crucible after pulling the silicon single crystal and the polycrystalline silicon remaining in the quartz crucible can be safely and efficiently recovered from the quartz crucible supporting the crucible without destroying it. Development of the device was awaited.

  Therefore, the present inventors have paid attention to the fact that the graphite crucible holding the quartz crucible can be divided into two, and have intensively studied whether the problem can be solved by using this structure.

  As a result, the present inventors placed a recovery container under a graphite crucible that can be divided into two parts, mechanically opened the graphite crucible left and right, and recovered the quartz crucible and polycrystalline silicon supported therein. The present invention was completed based on the idea that it can be efficiently recovered by dropping it into a container.

Hereinafter, the present invention will be described in more detail with reference to the drawings, but the present invention is not limited thereto.
FIG. 1 is a diagram showing an example of a quartz crucible and polycrystalline silicon recovery apparatus according to the present invention. FIG. 2 is a view showing an example of a state when the table on which the graphite crucible is placed is opened to the left and right.
The recovery apparatus of the present invention illustrated in FIGS. 1 and 2 includes at least an opening / closing table 9 for placing the graphite crucible 1, a mechanism 11 for opening / closing the table 9, a quartz crucible 2 and a polycrystalline silicon 3. And a collection container 4 for collection.

Here, the edge of the opening / closing part of the left / right opening / closing table 9 can be shaped like a standing claw 10 as shown in FIG.
Thus, the graphite crucible is easily opened to the left and right by placing the graphite crucible so that the edge of the opening and closing part of the table has a raised claw shape and the raised claw is inserted into the gap of the graphite crucible that can be divided into two. It becomes possible. That is, the quartz crucible and the polycrystalline silicon can be more easily dropped and collected from the graphite crucible.
The height of the standing nail shape is preferably higher by about +5 to 10 mm than the bottom thickness of the graphite crucible in order to float the quartz crucible from the graphite crucible when the nail is inserted into the gap between the graphite crucibles.
Further, as shown in FIG. 3, it is desirable that the nail shape has a radius that matches the elliptical shape of the bottom of the quartz crucible. FIG. 3 is a diagram showing an example of the edge shape of the opening / closing part of the table in the present invention. By adopting such a shape, the quartz crucible can be floated easily when the nail is inserted into the gap between the graphite crucibles.

Moreover, the drive source of the mechanism 11 that opens and closes the table 9 can be a manual type or an electric type.
That is, as a driving source for mechanically opening the graphite crucible by sliding the open / close table 9 from closed to open, the table may be slid left and right by manually turning a handle, or a motor You may make it slide a table electrically using. The manual method is simple and low in cost. The electric type has the advantage of good workability.
By driving the table opening / closing mechanism 11 manually or electrically, the table can be easily opened / closed, that is, the graphite crucible can be easily mechanically opened, and the quartz crucible and polycrystalline silicon can be opened. Can be easily recovered.

Further, in order to efficiently transfer the recovery container between different levels or between different chambers, a mechanism for transferring the recovery container to the lower part of the table or the setting position of the recovery container can be provided.
Since the recovery container after recovering the quartz crucible and polycrystalline silicon can be very heavy, it is possible to facilitate the movement of the recovery container by providing a mechanism for transporting the recovery container in this way. Out. Moreover, since an empty collection container can also be easily transferred by such a transfer means, it is also easy to transfer the collected container to the original position.

As a mechanism for transferring the recovery container, specifically, at least the lifter 5, the conveyors 6, 7 and the like can be provided.
The lifter 5 can move the collection container 4 up and down. The lifter 5 can move the collected container from the second floor to the first floor or move the empty container to the collection position from the first floor to the second floor. Can be transported. Further, the containers 4 on the first floor can be transferred to a predetermined position by being conveyed and carried by the conveyor 7. A separate carry-in conveyor 6 may be provided.
Thus, by providing at least the lifter and / or the conveyor, the collection container can be transferred smoothly and easily.

Next, a method for recovering the quartz crucible and polycrystalline silicon according to the present invention will be described.
After pulling up the single crystal by the CZ method, the quartz crucible 2 holding the raw material melt and the remaining hot water remaining in the quartz crucible are supported in the graphite crucible 1.
After the pulling of the silicon single crystal is completed, the quartz crucible 2 and the remaining melt of the raw material melt (the same applies to the graphite crucible 1) are very hot, and are allowed to cool.

After sufficiently cooling the graphite crucible 1, the quartz crucible 2, and the remaining hot water, the polycrystalline crucible 3 solidified by cooling the remaining hot water and the quartz crucible 2 is supported by using a crucible lifting jig or the like. And lift it with an electric hoist installed on the ceiling.
At this time, as the crucible lifting jig, for example, the same one as described in JP-A-5-286585 can be used.

Using such a lifting jig, in a state where the graphite crucible 1 is lifted, the graphite crucible 1 is moved right above the left-right openable table 9 and lowered onto the table 9.
Here, when placing the graphite crucible 1 on the table 9, it can be set so that the standing claws 10 of the table opening and closing part are inserted into the gap into which the graphite crucible 1 is divided.

  Further, it is desirable that the table 9 is provided with a fall prevention support 8 for preventing the graphite crucible from falling. As the overturn prevention support jig 8, for example, a clamp type support or the like can be provided. The fall prevention support jig 8 supports the body of the graphite crucible 1 and can prevent the graphite crucible 1 from falling when the table 9 is opened left and right.

When the table is opened, the graphite crucible is mechanically opened to the left and right by the vertical claws inserted in the gap between the graphite crucibles, and the polycrystalline crucible remaining in the quartz crucible and the quartz crucible falls directly below.
Here, the drive of the mechanism for opening and closing the table can be manual or electric, such as a structure in which a gear is manually rotated by a handle as described above, or a structure in which a motor is used to open and close electrically.

  A recovery container 4 is set below the open / close table 9, and the dropped quartz crucible 2 and the polycrystalline silicon 3 remaining in the quartz crucible 2 are dropped into the recovery container 4 and recovered.

Here, in order to set the collection container 4 under the table 9, an empty container supply side conveyor 6, a lifter (vertical transfer machine) 5, a collected container carry-out side conveyor 7, and the like can be provided.
Since the recovery container after recovering the quartz crucible and polycrystalline silicon is very heavy, it is possible to facilitate the movement of the recovery container by providing a mechanism for transferring the recovery container in this way. it can. Also, an empty collection container can be easily carried and transferred by such transfer means.
It is desirable to stock a plurality of empty collection containers or collection containers that have been collected on a conveyor or the like. As a result, it is not necessary to set the collection container in a transfer mechanism such as a conveyor each time the collection is performed, and the working efficiency can be further improved.

Thus, in the present invention, utilizing the fact that the graphite crucible supporting the quartz crucible can be divided into two parts, the graphite crucible and the quartz crucible supported therein are opened by mechanically opening the graphite crucible to the left and right. The polycrystalline silicon inside is dropped, and the quartz crucible and polycrystalline silicon dropped in the collection container are collected.
This eliminates the need for crushing the quartz crucible and eliminates the need for crushing the quartz crucible and collecting it manually by the operator, making it extremely safe. Can do. Further, it is possible to save the trouble of taking out the fragments from the graphite crucible, greatly reduce the burden on the operator, and greatly improve the recovery efficiency.
Furthermore, since the risk of breaking the graphite crucible can be greatly reduced, it can be easily reused.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. Supported by the technical scope of the invention.

It is the schematic which shows an example of the collection | recovery apparatus of the quartz crucible and polycrystalline silicon of this invention. It is the figure which showed an example at the time of opening the table which mounts the graphite crucible in this invention right and left. It is the figure which showed an example of the shape of the edge of the opening-and-closing part of the table in this invention. It is the figure which showed an example of the single crystal manufacturing apparatus by the conventional CZ method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Graphite crucible, 2 ... Quartz crucible, 3 ... Polycrystalline silicon, 4 ... Collection | recovery container, 5 ... Lifter (vertical conveyance machine), 6 ... Empty container supply side conveyor, 7 ... Collected container carrying-out side conveyor, 8 ... Overturn Prevention support jig, 9 ... Opening / closing table, 10 ... Standing claw, 11 ... Table opening / closing mechanism,
DESCRIPTION OF SYMBOLS 21 ... Main chamber, 22 ... Pulling chamber, 23 ... Single crystal, 24 ... Raw material melt, 25 ... Quartz crucible, 26 ... Graphite crucible, 27 ... Heater, 28 ... Heat insulation member, 29 ... Gas outlet, 30 ... Gas introduction Mouth 31, gas flow rectifier 32, heat shield member 33, wire 34, seed holder 35, seed crystal, 36 shaft

Claims (6)

In the Czochralski method, after the completion of pulling of the silicon single crystal from the silicon melt in the quartz crucible supported by the graphite crucible that can be divided into two, the quartz crucible and the remaining silicon melt are cooled and solidified. A recovery method for recovering polycrystalline silicon from the graphite crucible,
After finishing the pulling of the silicon single crystal, the graphite crucible supporting the quartz crucible and the polycrystalline silicon is placed on a left-right openable table, and the table is mechanically opened left and right to open the table A graphite crucible that can be divided into two parts is opened to the left and right, and the quartz crucible supported in the graphite crucible and the polycrystalline silicon remaining in the quartz crucible are dropped into a collection container installed under the table. A method for recovering a quartz crucible and polycrystalline silicon, wherein the quartz crucible and the polycrystalline silicon are recovered. After pulling up the silicon single crystal from the silicon melt in the quartz crucible supported by the graphite crucible that can be divided into two by the Czochralski method, the quartz crucible and the remaining melt of the silicon melt are cooled and solidified. A recovery device for recovering silicon from within the graphite crucible,
At least, a left-right open / close table, a mechanism for opening and closing the table, and a recovery container for recovering the quartz crucible and the polycrystalline silicon,
The table is for placing the graphite crucible that can be divided into two parts,
When the table is mechanically opened left and right by the opening and closing mechanism, the graphite crucible is also opened left and right,
By opening the graphite crucible to the left and right, the quartz crucible supported by the graphite crucible and the polycrystalline silicon remaining in the quartz crucible are placed in the recovery container installed under the table. A quartz crucible and polycrystalline silicon recovery device, which is dropped and recovered.   3. The quartz crucible and polycrystalline silicon recovery apparatus according to claim 2, wherein the left and right open / close table has an open / close edge formed in an upright claw shape.   The quartz crucible and polycrystalline silicon recovery apparatus according to claim 2 or 3, wherein the mechanism for opening and closing the table is a manual opening type or an electric opening and closing type.   The quartz crucible and polycrystalline silicon recovery apparatus according to any one of claims 2 to 4, further comprising a mechanism for transporting the container to be recovered.   6. The quartz crucible and polycrystalline silicon recovery apparatus according to claim 5, wherein the transfer mechanism includes at least a lifter and / or a conveyor.

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