JP6503933B2 - Silicon melt supply apparatus and method, and silicon single crystal production apparatus - Google Patents

Description

  The present invention relates to a silicon melt supply apparatus and method, and more particularly to a silicon melt supply apparatus and method suitable for additional supply of silicon melt to a silicon single crystal pulling apparatus. The present invention also relates to a silicon single crystal production apparatus using such a silicon melt supply apparatus.

  In recent years, most of silicon single crystals that are materials of silicon wafers are manufactured by the Czochralski method (hereinafter referred to as the CZ method). The CZ method immerses a seed crystal on the liquid surface of a silicon melt contained in a quartz crucible, and slowly pulls the seed crystal while rotating the seed crystal and the quartz crucible, so that the lower end of the seed crystal and the seed crystal This is a method of growing a silicon single crystal having the same crystal orientation.

  In order to grow a large and long silicon single crystal, a large amount of silicon raw material is required. However, since the amount which can be filled with the raw material in the quartz crucible from the beginning is limited, it is necessary to additionally supply more raw material.

  As a method of additionally supplying a silicon raw material, for example, according to Patent Document 1, a melting crucible for producing a silicon melt is disposed at a position higher than a quartz crucible, and the melting crucible is moved to the quartz crucible using the difference in height between them. A method of supplying silicon melt through a transparent quartz tube is described. Further, Patent Document 2 describes a method of transporting a silicon melt with a pressure difference in a chamber. Further, in Patent Document 3, a silicon melt having a different impurity concentration from the silicon melt in the quartz crucible is filled in the melt supply portion disposed above the quartz crucible, and quartz from the melt supply portion is used. A method is described in which the impurity concentration of the silicon melt in the quartz crucible is always kept constant by additionally supplying the silicon melt to the crucible through the melt supply pipe.

  Further, Patent Document 4 describes a method of forming a silicon melt in an auxiliary crucible disposed above the pulling furnace and then dropping the silicon melt and supplying it into a quartz crucible in the pulling furnace. There is. Further, Patent Document 5 describes a method of melting polycrystalline silicon in a melter assembly mounted on a crystal puller, and transferring silicon melt to the crystal puller by supply utilizing its weight. There is.

Patent No. 4307516 JP 2012-106870 A JP-A-8-208371 Japanese Patent Application Laid-Open No. 11-92276 Patent No. 5080971 gazette

  However, since all the silicon melt supply methods described in Patent Documents 1 to 3 above are to send the silicon melt through the pipe obliquely inclined from the silicon melt supply source toward the quartz crucible, There is a problem that silicon melt tends to remain in the middle. When the piping is a quartz tube, the solidification of the silicon melt remaining in the quartz tube causes a crack in the quartz tube, making it impossible to reuse the quartz tube.

  Further, the silicon melt supply method described in Patent Document 4 has a problem that liquid splash is likely to occur since the silicon melt is supplied by dropping the silicon melt from above the quartz crucible. If the silicon melt spray adheres to the furnace internal parts such as the heat shield, the furnace internal parts may be damaged. Also, there is a problem that the silicon melt adhering to the parts in the furnace is solidified, and silicon dust liberated from the parts in the furnace is generated, and this enters into the quartz crucible during single crystal growth, thereby deteriorating the crystal quality.

  In addition, the silicon melt supply method described in Patent Document 5 also causes the silicon melt to be dropped and supplied from above the quartz crucible, so the same problem as that of Patent Document 4 occurs, but this problem It is described to use a quartz guide tube (flow guide) when dropping the silicon melt against it (see FIG. 21C). According to this configuration, it is possible to reduce that the spray of silicon melt adheres to components in the furnace such as a heat shield.

  However, since the position of the quartz guide tube is fixed, splashing can not be sufficiently prevented, particularly when the silicon melt in the quartz crucible is small. In addition, if the silicon melt is excessively filled in the quartz crucible, the lower end of the quartz guide tube may be immersed in the silicon melt. When the quartz guide tube is in contact with a high temperature silicon melt for a long time, the quartz guide tube is deteriorated, and there is a problem that it can not be used in about 1 to 2 times. The quartz guide tube is long and large for that purpose. In the case of manufacturing a silicon single crystal having a diameter of 300 mm or more, it is particularly expensive because it becomes a long and large quartz guide tube, which raises the manufacturing cost of the silicon single crystal. Moreover, there is no description about the method of using a guide pipe made from quartz effectively that the spray of a silicon melt adheres to components in furnaces, such as a heat shield.

  Furthermore, when the quartz guide tube is fixed, the diameter of the silicon single crystal to be grown is the opening of the quartz guide tube because the quartz guide tube is always disposed in the furnace during single crystal growth. There is also the problem of being limited to less than the diameter. Another problem is that the life of the quartz guide tube is shortened because the quartz guide tube is always kept at high temperature.

  Therefore, the object of the present invention is to prevent clogging of the raw material in the supply path and adhesion of silicon melt to parts in the furnace when supplying silicon melt into the quartz crucible, and it is possible to reduce running cost at low cost. It is an object of the present invention to provide a silicon melt supply apparatus and method. Another object of the present invention is to provide a highly reliable single crystal silicon manufacturing apparatus using such a silicon melt supply apparatus.

  In order to solve the above problems, a silicon melt supply apparatus according to the present invention is a silicon melt supply apparatus for supplying a silicon melt into a quartz crucible installed in a main chamber of a silicon single crystal pulling apparatus, A sub-chamber connected to the upper opening of the main chamber, a container installed in the sub-chamber, a heater for heating silicon raw material in the container to generate silicon melt, and the container to the quartz crucible A cylindrical quartz tube forming the supply path of the silicon melt, and the quartz tube is vertically and vertically provided above the quartz crucible, and the silicon melt in the container is And dropping from above the quartz tube through the inside of the quartz tube and filling the inside of the quartz crucible.

  In the silicon melt supply method according to the present invention, a silicon single crystal is pulled up having a main chamber, a cylindrical pull chamber connected to an upper opening of the main chamber, and a quartz crucible disposed in the main chamber. A method for supplying silicon melt into the quartz crucible in an apparatus, wherein the pull chamber is removed, and a cylindrical quartz tube is inserted into the main chamber from the upper opening of the main chamber, and then the quartz A silicon melt is injected into the quartz tube vertically disposed just above the crucible, and the silicon melt dropped through the quartz tube is filled in the quartz crucible.

  Furthermore, the silicon single crystal production apparatus according to the present invention comprises a silicon single crystal pulling apparatus for producing a silicon single crystal, and a silicon melt supply apparatus for supplying a silicon melt to the silicon single crystal pulling apparatus, The single crystal pulling apparatus includes a main chamber and a quartz crucible installed in the main chamber, the silicon melt supply device includes a sub chamber connected to an upper opening of the main chamber, and the inside of the sub chamber A heater installed in the container, a heater for heating the silicon raw material in the container to generate a silicon melt, and a cylindrical quartz tube forming a supply path of the silicon melt from the container to the quartz crucible And the quartz tube is vertically and vertically disposed above the quartz crucible. Ri, the silicon melt in the container is dropped from above the quartz tube through the said quartz tube, characterized in that it is filled in the quartz crucible.

  According to the present invention, the additional silicon melt generated outside the main chamber can be supplied vertically from directly above the quartz crucible. Therefore, the silicon melt is not clogged and solidified in the middle of the quartz tube, and the additional silicon melt can be safely supplied into the quartz crucible. In addition, since the area around the additional silicon melt falling position is surrounded by the quartz tube, it is possible to prevent the silicon melt from adhering to the in-furnace parts. Therefore, damage to components in the furnace and generation of silicon dust can be prevented. In addition, even if a large amount of silicon melt is continuously injected, there is no problem of liquid splashing, so that additional supply of silicon melt can be completed in a short time.

  In the present invention, the quartz tube may be a first position extracted from the main chamber and accommodated in the sub chamber, and a second position inserted into the main chamber from an upper opening of the main chamber. And the upper end of the quartz tube is positioned lower than the supply position of the silicon melt from the container in the second position, and the lower end of the quartz tube is in the quartz crucible. It is preferable to be located above the liquid level of the silicon melt. In particular, the distance from the lower end of the quartz tube at the second position to the liquid level of the silicon melt in the quartz crucible is preferably 5 mm or more and 30 mm or less. According to this configuration, since the circumference of the drop point of the silicon melt is surrounded by the quartz tube, it is possible to effectively prevent the spray of the silicon melt from adhering to the components in the furnace. Therefore, damage to components in the furnace and generation of silicon dust can be prevented. In addition, even if a large amount of silicon melt is continuously injected, there is no problem of liquid splashing, so that additional supply of silicon melt can be completed in a short time. Furthermore, when the quartz tube is not used, it is elevated and accommodated in the sub-chamber, so that the device space can be reduced, and the device can be miniaturized. Since the distance from the lower end of the quartz tube in the second position to the liquid surface is short, the lower end of the quartz tube may be in contact with the silicon melt when the liquid surface is greatly wavy, but it is always in contact Since this is not the case, the reaction between the quartz tube and the high temperature silicon melt can be reduced, and the deterioration of the quartz tube can be minimized.

  The silicon melt supply apparatus according to the present invention further comprises a transfer mechanism for transferring the sub-chamber connected to the upper opening of the main chamber to another place, the quartz tube is extracted from the main chamber and the sub-chamber is It is preferable to be transferred together with the sub-chamber while being accommodated in the chamber. As described above, when the quartz tube is not used, it is lifted and accommodated in the sub-chamber, so that the device space can be suppressed, and the device can be miniaturized.

  In the present invention, preferably, the container is tiltable, and the silicon melt in the container is injected into the quartz tube by tilting the container. According to this configuration, the container may not be disposed on the elevating line of the quartz tube, and the elevating operation of the quartz tube is not hindered. Also, the silicon melt in the container can be taken out by a simple operation.

  In the silicon melt supply apparatus according to the present invention, during the filling of the silicon melt in the container into the quartz crucible, the quartz crucible is gradually increased according to the rise of the liquid level of the silicon melt in the quartz crucible. It is also preferable to gradually raise the quartz tube as the liquid level of the silicon melt in the quartz crucible rises. According to this, it is possible to maintain the lower end of the quartz tube not in contact with the liquid surface of the silicon melt in the quartz crucible, and to prevent the deterioration of the quality of the quartz tube. Note that the control to move the quartz tube up and down while filling the silicon melt monitors the mirror image of the quartz tube reflected on the liquid surface by the operator and manually moves the quartz crucible or quartz tube up and down to the distance between the liquid surface and the lower end of the quartz tube And a method of calculating the supply amount (supply rate) of silicon melt and automatically moving the quartz crucible and the quartz tube up and down.

  Preferably, the silicon melt supply apparatus according to the present invention further comprises a magnetic field application apparatus for applying a horizontal magnetic field to the silicon melt in the quartz crucible during the supply of the silicon melt into the quartz crucible. Usually, the magnetic field application device is used for the purpose of suppressing the heat convection of the silicon melt in the single crystal pulling process and for reducing the oxygen content of the silicon melt, but by using it in the silicon melt supplying process. The flap of the surface of the silicon melt can be suppressed, and the spray of the silicon melt can be prevented from adhering to the lower end portion of the quartz tube.

  Preferably, the silicon melt supply apparatus according to the present invention further comprises a material feeder for supplying a silicon material into the container in the sub-chamber connected to the upper opening of the main chamber. According to this, the process of producing the silicon melt in the container and feeding the same into the quartz crucible can be repeated a plurality of times, and a large amount of the silicon melt can be fed.

  According to the present invention, when the silicon melt is supplied into the quartz crucible, the raw material clogging of the supply path and the adhesion of the silicon melt to the parts in the furnace are prevented, and the expensive consumable product is a quartz tube. It is possible to provide a silicon melt supply apparatus and method that can be used, and that can reduce running costs inexpensively. Further, according to the present invention, it is possible to provide a highly reliable silicon single crystal production apparatus using such a silicon melt supply apparatus.

FIG. 1 is a schematic cross-sectional view showing the entire configuration of a silicon single crystal production apparatus 1 according to a preferred embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing the configuration of the silicon single crystal pulling apparatus 10. As shown in FIG. FIG. 3 is a schematic cross-sectional view showing the configuration of the silicon single crystal production apparatus 1 in the silicon melt supply step, in which the silicon melt supply apparatus 20 is connected to the silicon single crystal pulling apparatus 10. FIG. 4 is a schematic cross-sectional view for illustrating in detail the configuration of FIG. 3 and for explaining the operation of the silicon melt supply apparatus 20 in detail. FIG. 5 is a schematic cross-sectional view for explaining the operation of the silicon melt supply apparatus 20 in detail. FIG. 6 is a schematic cross-sectional view for explaining the operation of the silicon melt supply apparatus 20 in detail. FIG. 7 is a schematic cross-sectional view for explaining the operation of the silicon melt supply apparatus 20 in detail.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic cross-sectional view showing the entire configuration of a silicon single crystal production apparatus 1 according to a preferred embodiment of the present invention.

  As shown in FIG. 1, the silicon single crystal production apparatus 1 includes a silicon single crystal pulling apparatus 10, a silicon melt supply apparatus 20 for supplying a silicon melt to the silicon single crystal pulling apparatus 10, and a silicon melt supply apparatus 20. And a raw material feeder 30 for supplying silicon raw material thereto. The raw material feeder 30 is an apparatus different from the silicon melt supply apparatus 20 in a narrow sense, but is a part of the silicon melt supply apparatus 20 in a broad sense.

  FIG. 1 shows the state during the single crystal pulling process, and the silicon melt supply device 20 and the raw material feeder 30 stand by at a predetermined lowered position (standby position) away from the silicon single crystal pulling device 10. The silicon melt supply apparatus 20 and the raw material feeder 30 are movable in the vertical direction and the horizontal direction, and are connected to the silicon single crystal pulling apparatus 10 in a silicon melt supply process described later.

  FIG. 2 is a schematic cross-sectional view showing the configuration of the silicon single crystal pulling apparatus 10. As shown in FIG.

  As shown in FIG. 2, the silicon single crystal pulling apparatus 10 includes a main chamber 11A, an elongated cylindrical pull chamber 11B connected to an upper opening 11Ao of the main chamber 11A, and silicon melt 3 in the main chamber 11A. It comprises a quartz crucible 12 to be held, a graphite susceptor 13 to support the quartz crucible 12, and a rotary support shaft 14 to support the quartz crucible 12 together with the susceptor 13 so as to be movable up and down. The rotary support shaft 14 is vertically moved and rotationally driven by a drive mechanism (not shown).

  The silicon single crystal pulling apparatus 10 includes a heater 15 disposed to surround the susceptor 13, a substantially inverted truncated conical heat shield 16 disposed above the quartz crucible 12, and the quartz crucible 12. A horizontal magnetic field (transverse magnetic field) is applied to the inside of the main chamber 11A and the pull-up wire 17 disposed above and coaxially with the rotation support shaft 14, the wire winding mechanism 18 disposed above the pull chamber 11B And a magnetic field applying device 19 for The above-described quartz crucible 12, susceptor 13, rotation support shaft 14, heater 15, and heat shield 16 are provided in the main chamber 11A, and the magnetic field application device 19 is provided outside the main chamber 11A.

  The heat shield 16 is provided above the silicon melt 3 so as to surround the growing silicon single crystal 2. The wire winding mechanism 18 is disposed above the pull chamber 11B, and the wire 17 extends downward from the wire winding mechanism 18 through the inside of the pull chamber 11B, and the tip of the wire 17 is the inside of the main chamber 11A. It has reached space. FIG. 2 shows a state in which the silicon single crystal 2 in the process of being grown is hung on the wire 17.

  In the process of pulling up the silicon single crystal, first, the quartz crucible 12 set in the susceptor 13 is filled with a silicon raw material such as polycrystalline silicon. Next, the silicon raw material is heated by the heater 15 to generate the silicon melt 3, and the seed crystal attached to the tip of the wire 17 is lowered and made to adhere to the silicon melt 3. Thereafter, the seed crystal is slowly raised while rotating the seed crystal and the quartz crucible 12, respectively, to grow a substantially cylindrical silicon single crystal 2.

  In general, when the single pulling process of silicon single crystal 2 using initial silicon melt 3 in quartz crucible 12 is completed, the whole single crystal pulling process is completed, and the temperature in the chamber is gradually lowered to normal temperature. The silicon single crystal ingot is taken out of the chamber, and the chamber is disassembled and cleaned. However, in order to produce silicon single crystals more efficiently, it is preferable that a plurality of pulling steps be performed continuously. When continuous pulling of the silicon single crystal is performed as described above, additional supply of the silicon source into the quartz crucible 12 is required. In addition, even if as many polycrystalline silicon lumps as possible are first packed into the quartz crucible 12, the volume of the silicon decreases when it is melted, and a vacant capacity is generated in the quartz crucible 12. In order to pull up a single crystal as long as possible in a single pulling process, it is necessary to minimize the free space in the quartz crucible 12, and for that purpose, it is preferable to replenish the silicon source. The silicon melt supply device 20 is used for such additional supply of silicon raw material.

  FIG. 3 is a schematic cross-sectional view showing the configuration of the silicon single crystal production apparatus 1 in the silicon melt supply step, in which the silicon melt supply apparatus 20 is connected to the silicon single crystal pulling apparatus 10. 4 to 7 are schematic sectional views for illustrating the configuration of FIG. 3 in more detail and for explaining the operation of the silicon melt supply apparatus 20 in detail.

  As shown in FIG. 3, in the silicon melt supplying step, the pull chamber 11B of the silicon single crystal pulling apparatus 10 is removed from the main chamber 11A, and the silicon melt supply unit instead of the pull chamber 11B above the main chamber 11A. 20 is installed, and further, a raw material feeder 30 is installed above the silicon melt supply apparatus 20. The pull chamber 11B is moved to a predetermined retraction position (not shown). The silicon melt supply apparatus 20 is transferred by the transfer mechanism 22 above the main chamber 11A, and the material feeder 30 is transferred by the transfer mechanism 32 above the main chamber 11A.

  As shown in FIG. 4, the silicon melt supply apparatus 20 includes a sub chamber 21 connected to the upper opening 11 Ao of the main chamber 11 A, a container 23 provided in the sub chamber 21, and silicon raw material 4 in the container 23. And a vertically movable quartz tube 25 provided in the sub-chamber 21. The raw material feeder 30 also includes a raw material supply valve 31. Although the method of raising and lowering the quartz tube 25 is not particularly limited, the quartz tube 25 can be suspended on a wire and the quartz tube 25 can be raised and lowered by using a wire winding mechanism as in the method of pulling up the silicon single crystal 2, for example. . In this case, the wire winding mechanism 18 actually used for pulling up the silicon single crystal 2 may be used both for lifting and lowering the silicon single crystal 2 and lifting and lowering the quartz tube 25 (see FIG. 2). By doing this, the device cost can be reduced.

  The container 23 is made of, for example, carbon or quartz glass, and can accommodate about 100 kg of polycrystalline silicon lumps. The silicon raw material is heated by a heater 24 provided around the container 23 to generate a silicon melt. The container 23 can be tilted, and the silicon melt in the container 23 can be taken out by tilting the container 23. The volume of the container 23 is not particularly limited, but if it is too large, the load on the structure supporting the transfer mechanism 22 and the sub-chamber 21 at a high position is very large, so the volume of the container 23 should not be too large. In particular, the size should be smaller than that of the quartz crucible 12.

  The quartz tube 25 is an elongated cylindrical member made of quartz glass and is provided vertically. The quartz tube 25 is vertically formed straight and does not have any corners. In the standby state where the silicon melt is not supplied into the quartz crucible 25, the quartz tube 25 is disposed above the main chamber 11A and is accommodated in the sub-chamber 21, but drops when the silicon melt is supplied. Is inserted into the main chamber 11A. The length of the quartz tube 25 is preferably longer than the height from the lower end of the heat shield 16 to the upper opening 11Ao of the main chamber 11A. The diameter of the quartz tube 25 is preferably smaller than the diameter of the lower opening of the heat shield 16.

  Next, the operation of the silicon melt supply apparatus 20 will be described in detail with reference to FIGS. 4 to 7.

  As shown in FIG. 4, in the silicon melt supply step, the silicon melt supply device 20 and the raw material feeder 30 are transferred above the main chamber 11A, the sub chamber 21 is connected to the main chamber 11A, and the raw material feeder 30 is It is connected to the chamber 21. Thereafter, the raw material supply valve 31 of the raw material feeder 30 is opened to fill the container 23 in the sub-chamber 21 with polycrystalline silicon 4.

  Next, as shown in FIG. 5, the polycrystalline silicon 4 in the container 23 is heated by the heater 24 to melt the silicon raw material, and the silicon melt 5 is generated.

  Next, as shown in FIG. 6, the quartz tube 25 in the raised position (first position) is lowered. That is, the quartz tube 25 is inserted into the inside of the main chamber 11A from the upper opening 11Ao of the main chamber 11A and lowered to near the surface of the silicon melt 3 in the quartz crucible 12. When the quartz tube 25 is lowered to a predetermined lowered position (second position), the opening at the upper end of the quartz tube 25 is disposed below the supply position of the silicon melt from the container 23. On the other hand, the lower end of the quartz tube 25 is preferably located below the lower end of the heat shield 16. By doing this, it is possible to prevent the silicon melt from adhering to the heat shield 16.

  When lowering the quartz tube 25, it is preferable that the lower end of the quartz tube 25 be as close as possible to the liquid surface of the silicon melt 3 remaining in the quartz crucible 12, but it is necessary to prevent contact with the silicon melt 3. The distance h from the lower end of the quartz tube 25 to the liquid surface of the silicon melt 3 is preferably 5 mm or more and 30 mm or less. If the distance h is less than 5 mm, the tip of the quartz tube 25 may contact the silicon melt 3 frequently and the quartz tube 25 may be altered or deformed. When the distance h exceeds 30 mm, the spray of the silicon melt passes through the gap between the lower end of the quartz tube 25 and the liquid surface and splashes outside, and adheres to the internal components of the furnace such as the heat shield 16 It is because there is a possibility of reducing the life of the components in the furnace. Here, the liquid level as referred to herein means the liquid level when the silicon melt 3 in the quartz crucible 12 is brought to a stationary state by stopping the melt supply. As described above, the quartz tube 25 is vertically installed right above the quartz crucible 12, and the vertical supply path of the silicon melt 5 from the container 23 to the quartz crucible 12 is secured.

  Next, as shown in FIG. 7, the container 23 is tilted to pour the silicon melt 5 into the quartz tube 25. The container 23 is driven to tilt by a tilting mechanism 26. The silicon melt 5 is dropped down through the inside of the quartz tube 25 and is filled in the quartz crucible 12 in the main chamber 11A. Since the quartz tube 25 is installed vertically, even if the silicon melt 5 adheres to the inner wall surface of the quartz tube 25, it falls along the vertical smooth surface and falls by its own weight and remains in the quartz tube 25. Absent. Therefore, the quality of the quartz tube 25 is lowered by the solidification of the silicon melt 5 remaining in the quartz tube 25, and the problem that it can not be reused does not occur. Since the quartz tube 25 is an expensive part, the cost reduction effect by reuse is very large.

  The method of tilting the container 23 to pour out the silicon melt 5 is suitable for the mechanism for moving the quartz tube 25 up and down. For example, in the method of dropping the silicon melt from the discharge hole of the silicon melt formed at the bottom of the container 23, the container 23 needs to be disposed right above the quartz tube 25 and interferes with the elevating operation of the quartz tube 25. . However, in the case of tilting the container 23, the container 23 may not be disposed on the elevating line of the quartz tube 25, and the elevating of the quartz tube 25 is not hindered. Also, the silicon melt can be taken out with a simple operation.

  When the silicon melt is supplied into the quartz crucible 12, the quartz crucible 12 is gradually lowered according to the rise of the liquid level of the silicon melt 3 in the quartz crucible 12, or the quartz tube 25 is gradually It is preferable to raise it. By doing this, the distance from the liquid surface of the silicon melt 3 to the lower end of the quartz tube 25 can be kept constant, and the contact between the quartz tube 25 and the silicon melt 3 can be avoided.

  Since the lower end of the quartz tube 25 is close to the liquid level of the silicon melt 3 in the quartz crucible 12, the liquid level of the silicon melt 3 may come in contact with the liquid level when the liquid level is greatly wavy. However, since the lower end of the quartz tube 25 is not always in contact with the silicon melt 3, its effect is limited, and the lower end of the quartz tube 25 is not excessively deformed or deteriorated. That is, the deterioration of the quartz tube 25 due to the reaction with the silicon melt 3 can be suppressed as much as possible. Rather, if the spray generated when the silicon melt 5 is dropped adheres to the lower end of the quartz tube 25 and is retained, it is washed off by intermittent contact with the silicon melt 3, so the quartz tube 25 is removed. There is an advantage that the silicon melt is difficult to adhere to the lower end of the

  When the silicon melt 5 is supplied into the quartz crucible 12, it is preferable to operate the magnetic field application device 19 to apply a transverse magnetic field to the silicon melt 5. The central magnetic field strength of the transverse magnetic field is preferably 3000 to 4000 G. Usually, the magnetic field application device 19 is used for the purpose of suppressing the heat convection of the silicon melt 3 in the single crystal pulling step and achieving the oxygen reduction of the silicon melt 3, but this is used during the silicon melt supply step. By doing this, it is possible to suppress the rippling and splashing of the liquid surface of the silicon melt 3.

  Since the volume of the container 23 is not so large, it may not be possible to supply the necessary amount of silicon melt in one silicon melt supply step. In such a case, the silicon melt supply process may be repeated until the silicon melt 3 in the quartz crucible 12 becomes appropriate.

  When the filling amount of the silicon melt 3 in the quartz crucible 12 becomes an appropriate amount, the silicon melt supplying step is ended, the quartz tube 25 is raised and taken out from the main chamber 11A and accommodated in the subchamber 21. As described above, when the quartz tube 25 is not used, it is elevated and accommodated in the sub-chamber 21. Therefore, the device space can be suppressed, and the entire silicon single crystal manufacturing device can be miniaturized. Next, the sub chamber 21 is disconnected from the main chamber 11A, and the sub chamber 21 and the material feeder 30 are moved to the standby position (see FIG. 1). Thereafter, the pull chamber 11B is connected to the main chamber 11A, and the single crystal pulling process is started.

  As described above, the silicon single crystal production apparatus 1 according to the present embodiment includes the silicon melt supply apparatus 20 that supplies the silicon melt to the silicon single crystal pulling apparatus 10, and the silicon melt supply apparatus 20 includes the silicon single crystal A sub-chamber 21 connected to the upper opening 11Ao of the main chamber 11A of the crystal pulling apparatus 10, and a quartz tube forming a supply path of silicon melt from the container 23 in the sub-chamber 21 to the quartz crucible 12 in the main chamber 11A 25 and the quartz tube 25 is vertically vertically movable above the quartz crucible 12 in the main chamber 11A, and the silicon melt 5 generated in the subchamber 21 is transferred to the quartz crucible 25 from above the quartz tube 25. 12 to supply the quartz tube 25 with silicon melt Can be used as id, the silicon melt 5 can be surely supplied to the quartz crucible 12 in the main chamber 11A.

  In addition, since the additional silicon melt 5 is vertically supplied from directly above the quartz crucible 12, the silicon melt does not clog and solidify in the middle of the quartz tube 25, and the additional silicon melt 5 is melted in the quartz crucible 12. It can be supplied safely inside. In addition, by surrounding the position where the additional silicon melt 5 is dropped with the quartz tube 25, it is possible to prevent the liquid from splashing. Furthermore, since not only the drop point but also the entire periphery of the supply path is covered with the quartz tube 25, adhesion of the silicon melt 5 can be reliably prevented. Therefore, it is possible to prevent damage and early deterioration of components in the main chamber 11A such as the heat shield 16, the susceptor 13, and the quartz crucible 12. In addition, even if a large amount of silicon melt is continuously injected, there is no problem of liquid splashing, so that additional supply of silicon melt can be completed in a short time.

  Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. It is needless to say that they are included in the scope.

  For example, although the horizontal magnetic field is applied during the supply of the silicon melt 5 in the above embodiment, the application of the horizontal magnetic field is not essential. In the above embodiment, the container 23 is tilted to drop the silicon melt in the container 23. For example, an outlet is formed at the bottom of the container 23, and a valve for closing the outlet is opened to melt the silicon melt. The liquid 5 may be dropped. However, as described above, when the quartz tube 25 is configured to be movable up and down, it is preferable to tilt the container 23.

  In the above embodiment, the silicon melt supply apparatus 20 is installed above the single crystal pulling apparatus 10, the sub chamber 21 is connected to the upper opening of the main chamber 11A, and the material feeder is placed in the container 23 in the sub chamber 21. The polycrystal silicon is supplied from 30 and the polycrystal silicon in the container 23 is heated to generate the silicon melt 5. For example, before installing the silicon melt supply apparatus 20 above the single crystal pulling apparatus 10 After the silicon melt is generated in advance in the silicon melt supply apparatus 20, the silicon melt supply apparatus 20 may be transferred above the main chamber 11A. According to this method, the safety can be enhanced as compared with the case of melting polycrystalline silicon at a high place.

1 silicon single crystal production apparatus 2 silicon single crystal 3 silicon melt 4 polycrystalline silicon (silicon material)
5 silicon melt 10 silicon single crystal pulling apparatus 11A main chamber 11Ao upper opening 11B of main chamber pull chamber 12 quartz crucible 13 susceptor 14 rotation support shaft 15 heater 16 heat shield 17 wire 18 wire winding mechanism 19 magnetic field application device 20 silicon Melt feeder 21 Sub-chamber 22 Sub-chamber transfer mechanism 23 Container 24 Heater 25 Quartz tube 26 Tilting mechanism of container 30 Feeder 31 Feeding valve 32 Feeder transfer mechanism

Claims (11)

A silicon melt supply apparatus for supplying a silicon melt into a quartz crucible installed in a main chamber of a silicon single crystal pulling apparatus, comprising:
A sub chamber connected to an upper opening of the main chamber;
A container installed in the sub-chamber;
A heater for heating a silicon raw material in the container to generate a silicon melt;
A cylindrical quartz tube forming a supply path of the silicon melt from the container to the quartz crucible;
The quartz tube is provided vertically and vertically movable right above the quartz crucible,
The silicon melt in the container is dropped from above the quartz tube through the quartz tube and filled in the quartz crucible. The quartz tube is disposed between a first position extracted from the main chamber and accommodated in the sub chamber, and a second position inserted into the main chamber from an upper opening of the main chamber. Movable,
In the second position, the upper end of the quartz tube is located below the supply position of the silicon melt from the container, and the lower end of the quartz tube is higher than the liquid level of the silicon melt in the quartz crucible. The silicon melt supply apparatus according to claim 1, which is located above.   The silicon melt supply device according to claim 2, wherein a distance from a lower end of the quartz tube to a liquid level of silicon melt in the quartz crucible is 5 mm or more and 30 mm or less at the second position. The apparatus further comprises a transfer mechanism for transferring the sub-chamber connected to the upper opening of the main chamber to another place,
The silicon melt supply apparatus according to any one of claims 1 to 3, wherein the quartz tube is transferred together with the sub-chamber while being extracted from the main chamber and accommodated in the sub-chamber.   The silicon melt according to any one of claims 1 to 4, wherein the container is tiltable, and the silicon melt in the container is injected into the quartz tube by tilting the container. Liquid supply device.   The method according to claim 1, wherein during filling of the silicon melt in the container into the quartz crucible, the quartz crucible is gradually lowered according to the rise of the liquid level of the silicon melt in the quartz crucible. The silicon melt supply apparatus according to any one of the preceding claims.   The method as claimed in any one of claims 1 to 5, wherein during filling of the silicon melt in the vessel into the quartz crucible, the quartz tube is gradually raised according to the rise of the liquid level of the silicon melt in the quartz crucible. The silicon melt supply apparatus according to any one of the preceding claims.   The silicon according to any one of claims 1 to 7, further comprising a magnetic field application device for applying a horizontal magnetic field to the silicon melt in the quartz crucible during the supply of the silicon melt into the quartz crucible. Melt supply device.   The silicon melt supply apparatus according to any one of claims 1 to 8, further comprising: a raw material feeder configured to supply a silicon raw material into the container in the sub-chamber connected to the upper opening of the main chamber. A silicon melt is introduced into the quartz crucible in a silicon single crystal pulling apparatus having a main chamber, a cylindrical pull chamber connected to an upper opening of the main chamber, and a quartz crucible disposed in the main chamber. Supply method,
The pull chamber is removed, and a cylindrical quartz tube is inserted into the main chamber from the upper opening of the main chamber, and then silicon melt is placed in the quartz tube vertically disposed just above the quartz crucible. Filling the silicon melt injected and dropped through the quartz tube into the quartz crucible ;
The quartz crucible is gradually lowered according to the rise of the liquid level of the silicon melt, or the quartz tube is gradually raised to move the relative position of the quartz tube to the quartz crucible upward. Silicon melt supply method characterized by A silicon single crystal pulling apparatus for producing a silicon single crystal;
And a silicon melt supply apparatus for supplying silicon melt to the silicon single crystal pulling apparatus,
The silicon single crystal pulling apparatus is
With the main chamber,
And a quartz crucible installed in the main chamber,
The silicon melt supply apparatus
A sub chamber connected to an upper opening of the main chamber;
A container installed in the sub-chamber;
A heater for heating a silicon raw material in the container to generate a silicon melt;
A cylindrical quartz tube forming a supply path of the silicon melt from the container to the quartz crucible;
The quartz tube is provided vertically and vertically movable right above the quartz crucible,
The silicon melt in the container is dropped from above the quartz tube through the quartz tube and filled in the quartz crucible.