Single crystal manufacturing apparatus

Abstract

[Problem] To provide a single crystal production device equipped with a dopant supply device capable of supporting vertical movement of a heat shielding member without parts falling off or breaking. [Solution] The single crystal production device 1 is equipped with a chamber 10, a crucible 12 installed inside the chamber 10, a heat shielding member 16 disposed above the crucible 12, and a dopant supply device 20 that supplies a dopant from the outside of the chamber 10 to the inside of the crucible 12. The dopant supply device 20 includes a dopant supply tube 21 that passes through the chamber 10 and reaches to above the crucible 12. The dopant supply tube 21 has a first dope tube 24 that passes through the chamber 10 and a second dope tube 25 that is separate and independent from the first dope tube 24 and is disposed immediately below the first dope tube 24. The first dope tube 24 is separate and independent from the heat shielding member 16. The second dope tube 25 is separate and independent from the chamber 10 and is installed on the heat shielding member 16.

Description

Technical Field

[0001] The present invention relates to a single crystal manufacturing apparatus, and more particularly to a dopant supply apparatus used for supplying a dopant before or during the pulling process of a single crystal by the Czochralski method (CZ method).

Background Art

[0002] Many of the silicon single crystals used as substrate materials for semiconductor devices are manufactured by the CZ method. The CZ method involves immersing a seed crystal in a silicon melt contained in a quartz crucible, and gradually pulling up the seed crystal while rotating the seed crystal and the quartz crucible, thereby growing a single crystal with a large diameter below the seed crystal. According to the CZ method, it is possible to manufacture high-quality silicon single crystal ingots with a high yield.

[0003] Various dopants are used to adjust the electrical resistivity of silicon single crystals (hereinafter simply referred to as resistivity). Representative dopants include phosphorus (P), arsenic (As), antimony (Sb), boron (B), etc. These dopants are, for example, put into the quartz crucible together with polycrystalline silicon raw materials and melted together with the silicon raw materials by heating with a heater. Thereby, a silicon melt containing a predetermined amount of dopant is generated.

[0004] The dopant may be introduced into the silicon melt during the crystal pulling process. For example, antimony has a lower melting point than phosphorus or boron, and its evaporation rate is very fast under reduced pressure. Therefore, if it is melted together with polycrystalline silicon raw materials like phosphorus or boron, a large amount of dopant will evaporate from the raw material melting to the beginning of the crystal pulling process, and the dopant concentration in the silicon melt cannot be increased. Therefore, the dopant is additionally supplied during the crystal pulling process to suppress the decrease in the dopant concentration in the silicon melt.

[0005] Even when using a dopant with a relatively slow evaporation rate, the phenomenon of segregation of the supplied dopant along the pulling direction of the single crystal occurs, making it difficult to obtain a uniform resistivity in the pulling direction. To solve such problems, a method of supplying the dopant not only at the initial charge of the polycrystalline silicon raw material but also during the crystal pulling is effective. For example, by additionally supplying a dopant of the same conductivity type as the initially charged dopant, two types of silicon single crystals with significantly different resistivities can be pulled. Also, by additionally supplying a dopant of the opposite conductivity type to the initially charged dopant, the crystal length of the single crystal having a uniform resistivity in the pulling direction can be made as long as possible.

[0006] Regarding the method of supplying a dopant immediately before or during the pulling of a single crystal, for example, Patent Document 1 describes a dopant addition device including a dopant supply pipe that penetrates the upper part of the chamber and reaches above the crucible in the chamber, a sealing cap that seals the portion where the dopant supply pipe penetrates the chamber, a dopant hopper attached to the dopant supply pipe via a dopant supply cock outside the chamber, and a communication pipe that communicates the dopant hopper with the inside of the chamber. When supplying the dopant, the inside of the chamber is in an argon gas atmosphere under reduced pressure, but according to this dopant addition device, it is possible to adjust the inside of the dopant addition device to the same atmosphere as the inside of the chamber.

[0007] Also, Patent Document 2 describes a structure in which, even when a heat shielding member is disposed above the crucible, a dopant supply pipe disposed inside the heat shielding member above the heat shielding member is led out to the outside of the heat shielding member halfway, and at least the lower end portion of the dopant supply pipe faces the outside of the heat shielding member, so that the dopant can be supplied to the raw material melt in the crucible without problems.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0009] However, in the conventional dopant supply device, since a single dopant supply pipe is fixed to a chamber or a heat shielding member, breakage or detachment of parts often occurs. Further, the conventional dopant supply device cannot cope with a structure in which the heat shielding member is movable in the vertical direction, or restricts the movement of the heat shielding member.

[0010] Therefore, an object of the present invention is to provide a single crystal manufacturing apparatus including a dopant supply device that has no breakage or detachment of parts and can also cope with the vertical movement of a heat shielding member.

Means for Solving the Problems

[0011] To solve the above problems, a single crystal manufacturing apparatus according to the present invention includes a chamber, a crucible installed in the chamber, a heat shielding member disposed above the crucible, and a dopant supply device that supplies a dopant into the crucible from outside the chamber. The dopant supply device includes a dopant supply pipe that penetrates the chamber and reaches above the crucible. The dopant supply pipe has a first dopant pipe that penetrates the chamber and a second dopant pipe that is separated and independent from the first dopant pipe and is disposed immediately below the lower end of the first dopant pipe. The first dopant pipe is separated and independent from the heat shielding member, and the second dopant pipe is separated and independent from the chamber and is installed on the heat shielding member.

[0012] According to the present invention, it is possible to provide a single crystal manufacturing apparatus in which the installation of the dopant supply pipe is easy, there is no breakage or detachment of parts, and the vertical movement of the heat shielding member can also be coped with.

[0013] In the present invention, the first dope tube and the second dope tube may be completely separated from each other, or a part of the first dope tube may be inserted into the second dope tube. Further, when the first dope tube and the second dope tube are completely separated from each other, it is preferable to arrange the upper opening of the second dope tube directly below the lower end of the first dope tube. By making the first dope tube and the second dope tube have a structure separated and independent from each other, the first dope tube can be separated and independent from the heat shielding member, and the second dope tube can be separated and independent from the chamber (especially the top chamber).

[0014] In the present invention, it is preferable that the second dope tube is installed so as to be vertically movable with respect to the heat shielding member. According to this configuration, the installation of the second dope tube is easy, there is no breakage or dropping of parts, and it is possible to cope with the vertical movement of the heat shielding member.

[0015] In the present invention, the second dope tube preferably has a large-diameter portion having an opening diameter larger than the inner diameter of the lower end of the first dope tube, a small-diameter portion having an opening diameter smaller than the large-diameter portion, and a tapered portion connecting the large-diameter portion and the small-diameter portion. In this case, the large-diameter portion is arranged above the small-diameter portion, that is, on the side of the first dope tube. According to this configuration, the transfer of the dopant from the first dope tube to the second dope tube can be surely performed, and the installation of the second dope tube on the heat shielding member is also easy.

[0016] In the present invention, the taper angle (acute angle) of the outer surface of the tapered portion with respect to the vertical axis is preferably equal to or less than the inclination angle of the inner wall surface of the heat shielding member facing the tapered portion with respect to the vertical axis, and particularly preferably substantially equal to the inclination angle of the inner wall surface of the heat shielding member. Thereby, the second dope tube can be supported in a point contact or line contact state with respect to the heat shielding member, and breakage and deformation of the second dope tube can be suppressed.

[0017] In the present invention, it is preferable that the axis of the second doping tube extends linearly from the upper end to the lower end of the second doping tube. Thereby, a second doping tube that is easy and inexpensive to manufacture can be used.

[0018] In the present invention, it is preferable that the dopant supply tube is made of quartz. For example, when a dopant supply tube made of carbon is used, the carbon concentration in the silicon single crystal may increase due to carbon contamination of the dopant. However, when the dopant supply tube is made of quartz, impurity contamination of the dopant can be prevented. Quartz tubes are prone to cracking at room temperature and may undergo thermal deformation at high temperatures. However, when the second doping tube is simply inserted into the through-hole of the heat shielding member, breakage or deformation of the dopant supply tube can be prevented.

[0019] In the present invention, the heat shielding member is configured to be movable up and down within the chamber, and it is preferable that the relative positional relationship between the first doping tube and the second doping tube changes according to the up and down movement of the heat shielding member. According to this, the overall length of the dopant supply tube can be adjusted in accordance with the up and down movement of the heat shielding member, and the up and down movement of the heat shielding member is not restricted by the dopant supply tube. Further, when the heat shielding member is movable up and down, even if the crucible is filled with piled-up solid raw materials, interference between the heat shielding member and the solid raw materials can be avoided by retracting the heat shielding member upward, and the initial charge amount of the melt can be increased.

[0020] In the present invention, the chamber has a main chamber in which the crucible is installed and a top chamber that covers the upper opening of the main chamber. The top chamber is configured to be detachable from the main chamber, and preferably, the relative positional relationship between the first dope tube and the second dope tube changes according to the attachment and detachment of the top chamber. In this case, since the first dope tube is fixed to the top chamber side and the second dope tube is attached to the heat shielding member in the main chamber, it is easy to attach the top chamber to the main chamber or remove it from the main chamber.

[0021] In the present invention, the second dope tube is inserted into a through hole formed in the heat shielding member, and the lower end of the second dope tube terminates inside the lower opening end of the through hole without being exposed. Preferably, the lower end of the second dope tube is covered with a carbon ring cap. Since the second dope tube is only inserted into the through hole of the heat shielding member, its installation is easy. Further, since the lower end of the second dope tube is covered with the ring cap without being exposed, the lower end of the second dope tube can be protected from heat, and thermal deformation and the like can be prevented.

[0022] In the present invention, it is preferable that the outer opening of the ring cap is obliquely downward and faces the side wall portion side of the crucible. Thereby, even if the second dope tube has a shape extending straight downward, the dopant can be introduced as close as possible to the inner wall surface in the crucible, and liquid splashing of the molten liquid during introduction and dislocation of the single crystal can be prevented.

Effects of the Invention

[0023] According to the present invention, it is possible to provide a single crystal manufacturing apparatus provided with a dopant supply device that has no breakage or dropout of parts and can also cope with the vertical movement of the heat shielding member.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0025] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0026] FIG. 1 is a schematic side cross-sectional view showing the configuration of a single-crystal manufacturing apparatus according to an embodiment of the present invention.

[0027] As shown in FIG. 1, the single-crystal manufacturing apparatus 1 includes a chamber 10, a quartz crucible 12 installed in the chamber 10, a graphite susceptor 13 that supports the quartz crucible 12, a shaft 14 that supports the susceptor 13 so as to be movable up and down and rotatable, a heater 15 disposed around the susceptor 13, a heat shielding member 16 disposed above the quartz crucible 12, a single-crystal pulling wire 17 disposed above the quartz crucible 12 and coaxial with the shaft 14, a wire winding mechanism 18 disposed above the chamber 10, and a dopant supply device 20 that supplies a dopant into the quartz crucible 12.

[0028] Chamber 10 is composed of a main chamber 10a, a top chamber 10b covering the upper opening of the main chamber 10a, and an elongated cylindrical pull chamber 10c connected to the upper opening of the top chamber 10b. The quartz crucible 12, susceptor 13, heater 15, and heat shielding member 16 are provided inside the main chamber 10a. The susceptor 13 is fixed to the upper end of a shaft 14 provided vertically through the center of the bottom of the chamber 10, and the shaft 14 is driven to move up and down and rotate by a shaft drive mechanism 19.

[0029] The heater 15 is used to melt the polycrystalline silicon raw material filled in the quartz crucible 12 to generate a silicon melt 3. The heater 15 is a carbon resistance heater and is provided so as to surround the quartz crucible 12 inside the susceptor 13. A heat insulating material 11 is provided outside the heater 15. The heat insulating material 11 is arranged along the inner wall surface of the main chamber 10a, thereby enhancing the heat retention in the main chamber 10a.

[0030] The heat shielding member 16 is provided to prevent the silicon single crystal 2 from being heated by the radiant heat from the heater 15 and the quartz crucible 12 and to suppress the temperature fluctuation of the silicon melt 3. The heat shielding member 16 is a substantially cylindrical member whose diameter decreases from top to bottom, covers the upper part of the silicon melt 3, and is provided so as to surround the growing silicon single crystal 2. It is preferable to use graphite as the material of the heat shielding member 16. Since the lower end of the heat shielding member 16 is located inside the quartz crucible 12, there is no interference with the heat shielding member 16 even when the quartz crucible 12 is raised. An opening larger than the diameter of the silicon single crystal 2 is provided at the center of the heat shielding member 16, and the silicon single crystal 2 is pulled upward through the opening.

[0031] Although details will be described later, it is preferable that the heat shielding member 16 is configured to be movable up and down within the chamber 10. The heat shielding member 16 may be lifted by a jack or the like, or may be pulled up by a wire or the like. When the heat shielding member 16 is movable up and down, even if the quartz crucible 12 is filled with piled solid silicon raw materials, interference between the heat shielding member 16 and the solid silicon raw materials can be avoided by retracting the heat shielding member 16 upward, and the initial charge amount of the silicon melt 3 in the quartz crucible 12 can be increased.

[0032] Above the quartz crucible 12, a wire 17 which is the pulling axis of the silicon single crystal 2 and a wire winding mechanism 18 for winding the wire 17 are provided. The wire winding mechanism 18 has a function of rotating the silicon single crystal 2 together with the wire 17. The wire winding mechanism 18 is disposed above the pull chamber 10c, the wire 17 extends downward through the pull chamber 10c from the wire winding mechanism 18, and the tip of the wire 17 reaches the internal space of the main chamber 10a. FIG. 1 shows a state in which the silicon single crystal 2 being grown is suspended from the wire 17. When pulling up the single crystal, the seed crystal is immersed in the silicon melt 3, and the single crystal is grown by gradually pulling up the wire 17 while rotating the quartz crucible 12 and the seed crystal respectively.

[0033] At the upper part of the pull chamber 10c, a gas intake port 10d for introducing argon gas into the chamber 10 is provided, and at the bottom of the main chamber 10a, a gas exhaust port 10e for exhausting the argon gas in the chamber 10 is provided. Argon gas is introduced into the chamber 10 from the gas intake port 10d, and the introduction amount thereof is controlled by a valve. Also, since the argon gas in the sealed chamber 10 is exhausted to the outside of the chamber from the gas exhaust port 10e, it becomes possible to collect SiO gas and CO gas in the chamber 10 and keep the inside of the chamber 10 clean.

[0034] The dopant supply device 20 includes a dopant supply pipe 21 that penetrates the chamber 10 and reaches above the quartz crucible 12 at its lower end, a dopant hopper 22 installed outside the chamber 10 and connected to the upper end of the dopant supply pipe 21, and a seal cap 23 that seals the opening 10f of the top chamber 10b through which the dopant supply pipe 21 passes.

[0035] In the production of the silicon single crystal 2, the quartz crucible 12 is filled with a polycrystalline silicon raw material, and a seed crystal is attached to the tip of the wire 17. Next, the silicon raw material in the quartz crucible 12 is heated by the heater 15 to generate a silicon melt 3.

[0036] In the single crystal pulling process, first, necking of the seed crystal is performed by the dash necking method to make the single crystal dislocation-free. Next, a shoulder portion with a gradually increasing diameter is grown to obtain a single crystal with the required diameter, and a body portion with a constant diameter is grown when the single crystal reaches the desired diameter. After growing the body portion to a predetermined length, a tail portion is grown to separate the single crystal from the silicon melt 3 in a dislocation-free state.

[0037] The dopant 5 is supplied from the dopant supply device 20 to the silicon melt 3 immediately before the start of pulling the silicon single crystal 2 or during the crystal pulling process.

[0038] Figure 2 is an enlarged view of the dopant supply device 20 in Figure 1.

[0039] As shown in FIGS. 1 and 2, the dopant supply device 20 includes a dopant supply pipe 21 that penetrates the chamber 10 and reaches above the quartz crucible 12, a dopant hopper 22 connected to the upper end of the dopant supply pipe 21, and a seal cap 23 that seals the opening 10f formed in the top chamber 10b. The dopant raw material supplied from the dopant hopper 22 is transferred into the chamber 10 through the dopant supply pipe 21.

[0040] The dopant supply pipe 21 is made of quartz glass and is composed of a first dopant pipe 24 drawn into the main chamber 10a through the opening 10f of the top chamber 10b and a second dopant pipe 25 disposed in the main chamber 10a directly below the lower end of the first dopant pipe 24.

[0041] The first dopant pipe 24 is a quartz glass pipe that meanders from the installation position of the dopant hopper 22 through the opening 10f of the top chamber 10b to directly above the second dopant pipe 25. The first dopant pipe 24 is fixed to the top chamber 10b via a seal cap 23. The first dopant pipe 24 is separated and independent from the heat shielding member 16.

[0042] The second dopant pipe 25 has a large-diameter portion 25a having an opening diameter larger than that of the lower end of the first dopant pipe 24, a tapered portion 25b whose opening diameter gradually decreases, and a small-diameter portion 25c having an opening diameter smaller than that of the large-diameter portion 25a. That is, the second dopant pipe 25 has a funnel shape in which the opening size of its upper end portion is wider than that of its lower end portion.

[0043] The central axis of the second dopant pipe 25 extends linearly from its upper end to its lower end and has no bent portion. Therefore, the second dopant pipe 25 can be attached to the heat shielding member 16 simply by inserting the small-diameter portion 25c of the second dopant pipe 25 into the through-hole 16a. Since the shape of such a second dopant pipe 25 is relatively simple, it is easy to manufacture and the manufacturing cost is also low. The second dopant pipe 25 is only inserted into the through-hole 16a of the heat shielding member 16 and is installed so as to be vertically movable with respect to the heat shielding member 16. Furthermore, the second dopant pipe 25 is separated and independent from the chamber 10.

[0044] The heat shielding member 16 is provided with a through hole 16a penetrating vertically from the inner peripheral surface side to the outer peripheral surface side, and the small-diameter portion 25c of the second dope tube 25 is inserted into this through hole 16a. Since the periphery of the small-diameter portion 25c of the second dope tube 25 is surrounded by the heat shielding member 16, it is possible to suppress the influence of radiant heat from the heater 15 and the silicon melt 3 and prevent thermal deformation of the second dope tube 25.

[0045] The taper angle (acute angle) of the outer surface of the tapered portion 25b of the second dope tube 25 with respect to the vertical axis is preferably substantially equal to the inclination angle of the inner wall surface 16b of the heat shielding member 16 facing the tapered portion 25b with respect to the vertical axis. Thereby, the second dope tube 25 can be supported in a state of line contact with the heat shielding member 16, and breakage and deformation of the second dope tube 25 can be suppressed. Note that the apex of the taper angle is the lower end of the tapered portion 25b. The taper angle of the outer surface of the tapered portion 25b may be smaller than the inclination angle of the inner wall surface 16b facing the tapered portion 25b. In this case, the second dope tube 25 is supported by the heat shielding member 16 at a single point at the base of the tapered portion 25b, but it can be supported without problems.

[0046] As described above, both the first dope tube 24 and the second dope tube 25 are made of quartz. For example, when at least one of the first dope tube 24 and the second dope tube 25 is made of carbon, the carbon concentration in the silicon single crystal increases due to carbon contamination of the dopant. However, when both the first dope tube 24 and the second dope tube 25 are made of quartz, impurity contamination of the dopant can be prevented. Also, a quartz tube is likely to crack at normal temperature and may undergo thermal deformation at high temperature. However, the second dope tube 25 is simply inserted into the through hole 16a of the heat shielding member 16 and is not firmly fixed with a screw or the like. Therefore, not only is its installation easy, but breakage and deformation of the second dope tube 25 can be prevented.

[0047] The lower end of the small-diameter portion 25c of the second dope tube 25 inserted into the through-hole 16a of the heat shielding member 16 terminates inside the lower opening end of the through-hole 16a without being exposed, and the lower end of the second dope tube 25 is covered with a SiC-coated carbon ring cap 16c. Therefore, the lower end portion of the second dope tube 25 can be protected from heat, and thermal deformation and the like can be prevented.

[0048] Preferably, the outer opening of the ring cap 16c faces obliquely downward approaching the side wall portion of the quartz crucible 12. Thereby, even when the second dope tube 25 has a shape extending straight downward, the dopant 5 can be introduced as close as possible to the inner wall surface in the quartz crucible 12 (see FIG. 1), and liquid splashing of the melt during introduction and dislocation of the single crystal can be prevented.

[0049] In the above configuration, immediately before the start of pulling up the silicon single crystal 2 and during the crystal pulling process, granular dopant 5 is additionally supplied from the dopant supply device 20 to the silicon melt 3 in the quartz crucible 12. The dopant 5 discharged from the dopant hopper 22 is supplied to the silicon melt 3 through the first dope tube 24 and the second dope tube 25.

[0050] FIG. 3 is a schematic cross-sectional view showing a state in which the heat shielding member 16 is lifted at the preparation stage before starting the crystal pulling process.

[0051] As shown in FIG. 3, in the preparation stage, in order to charge as much silicon raw material 4 as possible into the quartz crucible 12, solid silicon raw materials 4 are piled up in the quartz crucible 12, and by melting this, a large amount of silicon melt 3 can be generated. At this time, by retracting the heat shielding member 16 upward so as not to interfere with the polycrystalline silicon raw material, it is possible to avoid interference between the heat shielding member 16 and the piled-up silicon raw materials 4. Further, since the dopant supply pipe 21 is divided into the first dope tube 24 and the second dope tube 25, it can correspond to the movement of the heat shielding member 16.

[0052] FIG. 4 is a schematic side cross-sectional view showing the chamber 10 in a disassembled state.

[0053] As shown in FIG. 4, the chamber 10 is composed of a combination of a main chamber 10a, a top chamber 10b, and a pull chamber 10c, and these can be disassembled as shown in the figure. At this time, since the dopant supply pipe 21 is divided into a first dopant pipe 24 and a second dopant pipe 25, it is easy to remove and attach the top chamber 10b to and from the main chamber 10a. Thus, the relative positional relationship between the first dopant pipe 24 and the second dopant pipe 25 changes according to the attachment and detachment of the top chamber 10b.

[0054] As described above, in the single crystal manufacturing apparatus 1 according to the present embodiment, since the dopant supply pipe 21 for feeding the dopant from the outside to the inside of the chamber 10 is split into two, the total length of the dopant supply pipe 21 can be adjusted in accordance with the movement in the vertical direction of the heat shielding member 16. Further, since the second dopant pipe 25 is only inserted into the through hole 16a of the heat shielding member 16, not only is its installation easy, but also breakage and deformation can be prevented.

[0055] As described above, the preferred embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention, and it goes without saying that those are also included in the scope of the present invention.

[0056] For example, in the above-described embodiment, the dopant supply pipe 21 is composed of two independent dopant pipes 24 and 25, but it is also possible to configure it using three or more dopant pipes.

[0057] For example, during the crystal pulling process, the first dopant pipe 24 and the second dopant pipe 25 are separated without overlapping in the vertical direction, but it is also possible to make them overlap.

Description of Reference Numerals

[0058] 1 Single crystal manufacturing apparatus 2 Single crystal silicon 3 Silicon melt 4 Solid silicon raw material 5 Dopant grains 10 Chamber 10a Main chamber 10b Top chamber 10c Pull chamber 10d Gas inlet 10e Gas outlet 10f Opening 11 Heat insulating material 12 Quartz crucible 13 Susceptor 14 Shaft 15 Heater 15b Tapered portion 16 Heat shield member 16a Through hole of heat shield member 16b Inner wall surface of heat shield member 16c Ring cap 17 Wire 18 Wire winding mechanism 19 Shaft drive mechanism 20 Dopant supply device 21 Dopant supply pipe 22 Dopant hopper 23 Seal cap 24 First doping pipe 25 Second doping pipe 25a Large diameter portion 25b Tapered portion 25c Small diameter portion

Claims

1. A chamber, a crucible installed in the chamber, a heat shielding member disposed above the crucible, and a dopant supply device for supplying granular dopant into the crucible from outside the chamber, wherein the dopant supply device includes a dopant supply pipe that penetrates the chamber and reaches above the crucible, the dopant supply pipe has a first dope pipe that penetrates the chamber and a second dope pipe that is separated and independent from the first dope pipe and is disposed directly below the lower end of the first dope pipe, the first dope pipe is separated and independent from the heat shielding member, the second dope pipe is separated and independent from the chamber and is installed on the heat shielding member, the heat shielding member is configured to be movable up and down in the chamber, and the relative positional relationship between the first dope pipe and the second dope pipe changes according to the up and down movement of the heat shielding member. A single crystal manufacturing apparatus characterized by this.

2. The single crystal manufacturing apparatus according to claim 1, wherein the second dope pipe is installed so as to be movable up and down with respect to the heat shielding member.

3. The single crystal manufacturing apparatus according to claim 1 or 2, wherein the second dope pipe has a large diameter portion having an opening diameter larger than the inner diameter of the lower end of the first dope pipe, a small diameter portion having an opening diameter smaller than the large diameter portion, and a tapered portion connecting the large diameter portion and the small diameter portion.

4. The single crystal manufacturing apparatus according to claim 3, wherein the taper angle of the outer surface of the tapered portion that forms an acute angle with respect to the vertical axis is equal to or less than the inclination angle with respect to the vertical axis of the inner wall surface of the heat shielding member facing the tapered portion.

5. The single crystal manufacturing apparatus according to any one of claims 1 to 4, wherein the axis of the second dope pipe extends linearly from the upper end to the lower end of the second dope pipe.

6. The single crystal manufacturing apparatus according to any one of claims 1 to 5, wherein the dopant supply pipe is made of quartz.

7. The chamber has a main chamber in which the crucible is installed and a top chamber that covers the upper opening of the main chamber. The top chamber is configured to be detachable from the main chamber, and the relative positional relationship between the first dope pipe and the second dope pipe changes according to the attachment and detachment of the top chamber. The single crystal manufacturing apparatus according to any one of claims 1 to 6.

8. The second doping tube is inserted into a through hole formed in the heat shielding member, a lower end of the second doping tube is terminated inside the lower opening end of the through hole without being exposed, and the lower end of the second doping tube is covered with a carbon ring cap. The single crystal manufacturing apparatus according to any one of claims 1 to 7.

9. The outer opening of the ring cap is obliquely downward and faces the side wall portion side of the crucible. The single crystal manufacturing apparatus according to claim 8.

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