JP2011057469A - Crucible opening retaining member and method and apparatus for producing single crystal silicon - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crucible opening retaining member where a used quartz crucible is reusable by preventing the deformation of the opening of a quartz crucible storing a silicon melt and to provide a method and an apparatus for producing single crystal silicon using the crucible opening retaining member. <P>SOLUTION: The crucible opening retaining member 60 to prevent the deformation of the opening of the quartz crucible 20 storing the silicon melt is characterized by being made of a material having higher strength at high temperature than that of the quartz crucible 20, including a stopping part 63 to perform stopping at the inner periphery of the sidewall of the quartz crucible 20 and preventing the such deformation that the opening end of the sidewall of the quartz crucible 20 is slumped to an inner peripheral side by the stopping part 63. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a crucible opening holding member for preventing deformation of an opening of a quartz crucible in which a silicon melt is stored, a method for manufacturing single crystal silicon using the crucible opening holding member, and a manufacturing apparatus for single crystal silicon. Is.

In recent years, power generation using a solar cell module has attracted attention as a power generation method with a low environmental load, and is widely used in various fields. Such a solar cell module includes a plurality of cells made of pn-bonded silicon semiconductor plates, and these cells are electrically connected by a solar cell interconnector and a bus bar.
With the widespread use of such solar cell modules, there is an increasing demand for single crystal silicon ingots that serve as semiconductor materials.

  Here, the single crystal silicon ingot is generally manufactured by the Czochralski method. In the Czochralski method, for example, as shown in Patent Documents 1 and 2, polycrystalline silicon is put in a quartz crucible placed in a high pressure-tight airtight chamber, and the polycrystalline silicon in the quartz crucible is heated and melted. Attach a seed (seed crystal) to the seed chuck placed above the quartz crucible and immerse this seed in the silicon melt in the quartz crucible, and pull up the seed while rotating the seed and the quartz crucible to grow single crystal silicon It is supposed to let you.

JP 2001-278696A Japanese Patent Laid-Open No. 01-294600

  By the way, in the single crystal silicon manufacturing apparatus described in Patent Documents 1 and 2, at the time when the pulling of the single crystal silicon is finished, it is maintained in a high temperature state for a long time. It is known that the opening end falls to the inner peripheral side and the opening of the quartz crucible is greatly deformed. Therefore, when the next single crystal silicon is pulled up, it is necessary to replace it with a new quartz crucible, and the quartz crucible after use has been disposed of. For this reason, there has been a problem that the manufacturing cost of single crystal silicon increases and the environmental burden associated with the manufacture of single crystal silicon increases.

  The present invention has been made in view of the above-mentioned circumstances, and prevents the deformation of the opening portion of the quartz crucible in which the silicon melt is stored, and enables the reuse of the quartz crucible after use. It is an object of the present invention to provide a single-crystal silicon manufacturing method and single-crystal silicon manufacturing apparatus using the crucible opening holding member.

  In order to solve the above-mentioned problems, a crucible opening holding member according to the present invention is a crucible opening holding member that prevents deformation of an opening of a quartz crucible in which silicon melt is stored. Is also made of a material having high high-temperature strength, and includes a locking portion that is locked to the inner peripheral surface of the side wall portion of the quartz crucible, and by this locking portion, the opening end of the side wall portion of the quartz crucible is on the inner peripheral side. It is characterized by being configured to prevent deformation so as to collapse.

  According to the crucible opening holding member of this configuration, the crucible opening holding member is made of a material having a higher temperature strength than that of the quartz crucible, and includes a locking portion that is locked to the inner peripheral surface of the side wall of the quartz crucible. Since the opening portion of the side wall portion of the quartz crucible is prevented from being deformed so as to collapse to the inner peripheral side by the portion, the deformation of the opening portion of the quartz crucible held at a high temperature for a long time is prevented. The opening of the quartz crucible after use can be held in the same shape as before use. Therefore, the quartz crucible after use can be used again, and the production cost of single crystal silicon and the environmental load can be reduced.

Here, in the crucible opening holding member, it is preferable that at least the locking portion is made of silicon carbide.
In this case, the rigidity of the locking portion is ensured even under high temperature conditions, and deformation of the opening of the quartz crucible can be reliably prevented. In addition, since the locking portion arranged on the inner peripheral side of the quartz crucible is less likely to break, it is possible to prevent impurities from being mixed into the silicon melt stored in the quartz crucible, and high quality single crystal silicon can be obtained. It becomes possible to produce.

  The method for producing single crystal silicon according to the present invention is a method for producing single crystal silicon in which a seed is immersed in a silicon melt stored in a quartz crucible arranged in a chamber, and the seed is pulled to grow single crystal silicon. The single crystal silicon is pulled up in a state where the aforementioned crucible opening holding member is attached to the quartz crucible, and after the pulling up of the single crystal silicon is completed, the used quartz crucible is reused. Yes.

According to the method for producing single crystal silicon having this structure, the above-described crucible opening holding member is attached to the quartz crucible to prevent the quartz crucible opening from being deformed after the pulling of the single crystal silicon is completed. Since the later quartz crucible is reused, the manufacturing cost of single crystal silicon can be greatly reduced. In addition, by reusing a quartz crucible that has been discarded only once in the past, it is possible to reduce the environmental burden associated with the production of single crystal silicon.
If the silicon melt remains in the quartz crucible, cracking may occur in the quartz crucible during the cooling process. Therefore, the silicon melt remaining in the quartz crucible when the pulling of the single crystal silicon is completed. It is preferable to remove the liquid.

Here, after coating the quartz film on the inner peripheral surface of the quartz crucible after use, it is preferable to reuse the quartz crucible for storing the silicon melt.
When the silicon melt is stored for a long time, the inner peripheral surface of the quartz crucible is deteriorated. Accordingly, by coating the inner peripheral surface of the quartz crucible after use with a quartz film, it becomes possible to use the quartz crucible after use in the same manner as a new quartz crucible. Thereby, even when the quartz crucible after use is reused, high-quality single crystal silicon can be produced.

  The single crystal silicon manufacturing apparatus according to the present invention is a single crystal silicon manufacturing method in which a seed is immersed in a silicon melt stored in silicon in a quartz crucible disposed in a chamber, and the seed is pulled to grow single crystal silicon. In the apparatus, the quartz crucible is provided with the aforementioned crucible opening holding member.

  According to the single crystal silicon manufacturing apparatus having this configuration, the opening of the quartz crucible is not deformed even after the pulling of the single crystal silicon is completed, and the quartz crucible can be reused. Therefore, single crystal silicon can be produced at low cost.

Here, the quartz crucible is accommodated in a graphite crucible disposed in the chamber, the crucible opening holding member is disposed at an upper end of the graphite crucible, and the locking portion is a side wall of the quartz crucible. It is preferable to be configured to be locked to the inner peripheral surface of the portion.
In this case, even if the crucible opening holding member is provided in the chamber, there is no risk of interference between the other members in the chamber and the crucible opening holding member, and the single crystal silicon can be pulled up stably. it can.

  According to the present invention, a crucible opening holding member that prevents deformation of an opening of a quartz crucible in which a silicon melt is stored and enables reuse of the quartz crucible after use, and the crucible opening holding member A method for producing single crystal silicon and an apparatus for producing single crystal silicon can be provided.

It is explanatory drawing which shows the manufacturing apparatus of the single crystal silicon provided with the crucible opening part holding member which is embodiment of this invention. It is expansion sectional explanatory drawing of the quartz crucible equipped with the crucible opening part holding member which is embodiment of this invention. It is a top view of a quartz crucible equipped with a crucible opening holding member according to an embodiment of the present invention. It is a flowchart which shows the manufacturing method of the single crystal silicon which uses the crucible opening part holding member which is embodiment of this invention. It is a top view of the quartz crucible equipped with the crucible opening holding member according to another embodiment of the present invention. It is a top view of the quartz crucible equipped with the crucible opening holding member according to another embodiment of the present invention. It is explanatory drawing which shows the manufacturing apparatus of the other single crystal silicon provided with the crucible opening part holding member which is embodiment of this invention. It is explanatory drawing of the residual silicon melt suction device with which the single crystal silicon manufacturing apparatus shown in FIG. 7 was equipped.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
First, the manufacturing apparatus of the single crystal silicon provided with the crucible opening holding member according to the present embodiment will be described.
In the single-crystal silicon manufacturing apparatus 10 shown in FIG. 1, a chamber 11 configured to be pressure-tight and airtight, a quartz crucible 20 in which a silicon melt M is stored, a crucible support base 22 that supports the quartz crucible 20, A heater 40 that heats the quartz crucible 20, a heat retaining cylinder 50 that surrounds the quartz crucible 20, a seed chuck 27 that holds a seed crystal (seed), and a seed chuck drive mechanism 30 that drives the seed chuck 27. And a crucible opening holding member 60 according to the present embodiment.

  The chamber 11 includes a main chamber 12, a top chamber 18 connected above the main chamber 12, and a pull chamber 19 connected above the top chamber 18. The main chamber 12 is erected on the bottom 13 and the bottom 13. The quartz crucible 20 is disposed at the center, and a vacuum pump (not shown) is connected to the exhaust hole so that the inside of the chamber 11 can be depressurized or evacuated. Yes.

Further, when the spill tray 16 is disposed at the bottom 13 of the main chamber 12 and the quartz crucible 20 is broken and the silicon melt M sometimes flows out, the silicon melt M directly contacts the bottom 13. Thus, the chamber 11 is prevented from being damaged.
The pull chamber 19 is formed in a substantially cylindrical shape, has a space for storing the pulled single crystal silicon T, and is connected to the main chamber 12 by the top chamber 18.
Further, the top chamber 18 is formed with a communication hole portion 18A that communicates the inside and the outside of the chamber 11, and a lid member 18B is attached to the communication hole portion 18A. Thereby, the inside of the chamber 11 is maintained in an airtight state.

The seed chuck 27 has a carbon chuck portion 28 formed of carbon on the distal end side. A hole is formed in the center of the distal end surface of the carbon chuck portion 28 from the distal end side to the proximal end side. A seed (seed crystal) S is inserted and fixed.
The seed chuck 27 is connected to the wire W at the base end side, and the wire W is connected to the seed chuck drive mechanism 30, so that the seed S can be rotated and raised / lowered relative to the main chamber 12.

  The seed chuck drive mechanism 30 is provided at the upper part of the pull chamber 19 and is connected to the proximal end side of the wire W and wound around the pulley 31 and the wire W as the rotation axis O so as to be rotatable relative to the pull chamber 19. And a rotational drive unit 32. In addition, a pull-up drive motor 33 that drives the pulley 31 to wind the wire W and a rotation drive motor 34 that rotates the rotation drive unit 32 are provided. The chuck 27 is moved up and down, and the rotation driving unit 32 is rotated so that the seed chuck 27 is rotated around the axis O.

The heat retaining cylinder 50 disposed in the chamber 11 has an inner heat retaining cylinder 51 made of cylindrical graphite and an outer heat retaining cylinder 52 made of cylindrical porous graphite disposed outside the inner heat retaining cylinder 51. ing. The heat retaining cylinder 50 is placed on a disc-like lower ring 54 in which a hole having substantially the same inner diameter as the inner heat retaining cylinder 51 is formed, and a hole having substantially the same inner diameter as that of the inner heat retaining cylinder 51 is provided above. The formed disk-shaped upper ring 55 is disposed.
Further, a flow pipe 48 is attached to the upper end of the heat retaining cylinder portion 50 via an upper ring 55 and an adapter 47. The flow pipe 48 is a hollow cylinder having an inverted frustoconical shape whose upper end opening is larger in diameter than the lower end opening, and is made of graphite or SiC.

A cylindrical heater 40 is disposed on the inner peripheral side of the heat retaining cylinder 50.
The heater 40 has a lower portion fixed to the electrode joint 41 with a bolt 42 at a part in the circumferential direction. The electrode joint 41 is connected to a power source (not shown) via a graphite electrode 43 disposed in a through hole formed in the spill tray 16. Connected with.

The quartz crucible 20 to which the crucible opening holding member 60 according to the present embodiment is attached is disposed on the inner peripheral side of the cylindrical heater 40.
The quartz crucible 20 is capable of holding lump-like polycrystalline silicon (silicon raw material), which is a raw material of single crystal silicon, in the concave portion, and can store a silicon melt M generated by heating and melting the polycrystalline silicon. ing. Here, the quartz crucible 20 is housed in a graphite crucible 21.

  The graphite crucible 21 is integrally formed by being held by a pedestal 24 disposed on the upper surface of the crucible support base 22. The crucible support 22 has a support shaft 23 inserted in a through hole 14 formed through the bottom 13 and the spill tray 16 at the center of the bottom 13 of the main chamber 12, and is connected to the support shaft 23. The motor 25 can be rotated and raised / lowered relative to the main chamber 12.

  Here, in a state where the quartz crucible 20 is accommodated in the graphite crucible 21, the upper end of the side wall portion of the quartz crucible 20 is configured to protrude upward from the graphite crucible 21 as shown in FIGS. 1 and 2. The crucible opening holding member 60 according to the present embodiment is attached to the protruding portion.

  As shown in FIG. 3, the crucible opening holding member 60 has an annular shape along a circle formed by the opening of the quartz crucible 20, and an annular groove 61 into which the upper end of the side wall of the quartz crucible 20 is inserted. Is formed. As shown in FIG. 2, the annular groove 61 causes the crucible opening holding member 60 to be in close contact with the outer peripheral surface of the side wall of the quartz crucible 20 and the inner periphery of the side wall of the quartz crucible 20. A locking part 63 that is locked to the surface and a connecting part 64 that connects the main body part 62 and the locking part 63 are defined.

As shown in FIG. 2, the locking portion 63 is brought into close contact with the inner peripheral surface of the side wall portion of the quartz crucible 20, and presses the opening end of the side wall portion of the quartz crucible 20 outward in the radial direction. It is configured.
In this embodiment, as shown in FIG. 2, the crucible opening holding member 60 is disposed so that the main body 62 is positioned at the upper end of the graphite crucible 21. Further, the entire crucible opening holding member 60 including the locking portion 63 disposed on the inner peripheral side of the quartz crucible 20 is made of silicon carbide, which is a material having a higher high-temperature strength than the quartz crucible 20.

Next, a single crystal silicon manufacturing method using the single crystal silicon manufacturing apparatus 10 will be described with reference to the flowchart shown in FIG.
First, massive polycrystalline silicon as a raw material is filled into the quartz crucible 20 (silicon raw material filling step S1). The quartz crucible 20 filled with polycrystalline silicon is transferred and accommodated in the graphite crucible 21, and the crucible opening holding member 60 is mounted on the upper end of the quartz crucible 20 (quartz crucible mounting step S2).

Next, the quartz crucible 20 is heated by the heater 40 to dissolve the polycrystalline silicon in the quartz crucible 20 to form a silicon melt M at 1420 ° C., and the silicon melt M in the vicinity where the seed S is immersed is supercooled. A state is set (silicon melting step S3).
Then, the seed S is inserted and fixed in the carbon chuck portion 28, the seed chuck drive mechanism 30 is driven, the seed chuck 27 is lowered, the seed S is immersed in the silicon melt M, and the seed S is melted into the silicon melt. Adapt to M (seed soaking step S4).

  When the seed S is familiar with the silicon melt M, the seed chuck 27 is raised at a speed of 0.5 mm / min to 3.5 mm / min while rotating the seed chuck 27 rightward in a plan view at, for example, 5 rpm to 20 rpm. By growing, single crystal silicon T having a circular cross section is grown (pulling step S5). In the pulling step S5, the quartz crucible 20 is rotated counterclockwise in plan view at, for example, 0.1 rpm to 5 rpm.

After the pulling of the single crystal silicon T is completed, the single crystal silicon T is taken out and preparation for manufacturing the next single crystal silicon is performed.
First, gas is introduced into the chamber 11 to obtain atmospheric pressure, the lid member 18B attached to the communication hole 18A provided in the top chamber 18 is removed, and the silicon remaining in the quartz crucible 20 through the communication hole 18A. The melt is removed by suction with a suction device (not shown) (residual silicon melt removal step S6).

Next, the quartz crucible 20 after use is taken out, and a quartz film is coated on the inner peripheral surface of the quartz crucible 20 after use (quartz film coating step S7).
Then, the quartz crucible 20 coated with the quartz film is filled with polycrystalline silicon as a raw material, and preparation for the next pulling of the single crystal silicon is performed.

  According to the single crystal silicon manufacturing method and single crystal silicon manufacturing apparatus 10 using the crucible opening holding member 60 according to the present embodiment configured as described above, the quartz crucible 20 includes the side wall portion of the quartz crucible 20. Since the crucible opening holding member 60 provided with the locking portion 63 locked to the inner peripheral surface of the quartz crucible 20 is mounted, the opening of the quartz crucible 20 remains on the inner peripheral side even after the pulling up of the single crystal silicon T Therefore, the opening of the quartz crucible 20 after use can be held in the same shape as before use, and the quartz crucible 20 after use can be used again. Therefore, the manufacturing cost of the single crystal silicon and the environmental load can be reduced.

  Further, in the crucible opening holding member 60, the entire crucible opening holding member 60 including the locking portion 63 arranged on the inner peripheral side of the quartz crucible 20 is a material having a higher high-temperature strength than the quartz crucible 20. Since it is made of silicon carbide, the rigidity of the entire crucible opening holding member 60 including the locking portion 63 is ensured even under high temperature conditions exceeding 1400 ° C., and the opening of the quartz crucible 20 is reliably deformed. Can be prevented. In addition, the locking portion 63 disposed on the inner peripheral side of the quartz crucible 20 is not easily damaged, and impurities can be prevented from being mixed into the silicon melt M stored in the quartz crucible 20. Silicon T can be produced.

  Furthermore, in this embodiment, the quartz crucible 20 is accommodated in the graphite crucible 21, and the upper end of the side wall portion of the quartz crucible 20 protrudes upward from the graphite crucible 21 in the accommodated state. Since the crucible opening holding member 60 is disposed so that the main body 62 is positioned at the upper end, the crucible opening holding member 60 attached to the quartz crucible 20 is connected to the seed S, the seed chuck 27, and the flow tube 48. The single crystal silicon T can be pulled up stably.

  Further, since the quartz film coating step S7 for coating the quartz film on the inner circumferential surface of the quartz crucible 20 after use is provided, a new quartz film is formed on the inner circumferential surface of the quartz crucible 20 that has deteriorated due to use. The used quartz crucible 20 can be used in the same manner as a new quartz crucible. Thereby, even when the quartz crucible 20 after use is reused, high-quality single crystal silicon T can be produced.

  Furthermore, in the present embodiment, a residual silicon melt removing step S6 is provided, in which the silicon melt remaining in the quartz crucible 20 through the communication hole 18A provided in the top chamber 18 is removed by suction with a suction device (not shown). Therefore, the generation of cracks in the quartz crucible 20 during the cooling process can be suppressed, and the quartz crucible 20 can be reliably reused.

As described above, the crucible opening holding member and the method and apparatus for producing single crystal silicon using the crucible opening holding member according to one embodiment of the present invention have been described, but the present invention is not limited thereto. The invention can be changed as appropriate without departing from the technical idea of the invention.
For example, although it has been described as a configuration in which an annular groove is provided and the upper end of the side wall portion of the quartz crucible is inserted into the annular groove, the present invention is not limited to this. For example, as shown in FIG. Even if the crucible opening holding member 160 is provided with an annular main body 162 on the outer peripheral side, and a plurality of connecting portions 164 and locking portions 163 that are divided from the main body 162 in the circumferential direction. Good.

Further, as shown in FIG. 6, the main body 262 is arranged on the outer peripheral side of the quartz crucible 20 in a circumferential direction, and the locking portion 263 located on the inner peripheral side of the quartz crucible 20 has an annular shape. It may be a crucible opening holding member 260 configured to make.
Further, the crucible opening holding member has been described as being composed entirely of silicon carbide. However, the present invention is not limited to this, and the material constituting the crucible opening holding member is a material having higher high-temperature strength than the quartz crucible. I just need it.
Further, the configurations of the chamber, the seed chuck, and the seed chuck drive mechanism are not limited to those described in the present embodiment, and the design may be changed as appropriate.

  Further, in the residual silicon melt removing step, the silicon melt in the quartz crucible is removed from the outside of the chamber using a suction device, but the present invention is not limited to this. For example, FIG. 7 and FIG. The remaining silicon melt suction device 70 shown in FIG. This residual silicon melt suction device 70 is arranged so that the nozzle portion 73 is immersed in the residual silicon melt in the quartz crucible 20, and introduces an inert gas such as argon gas into the chamber 11. Thus, a differential pressure is generated between the chamber 11 and the storage space 71 of the residual silicon melt suction device 70, and the residual silicon melt is suctioned and removed by this differential pressure.

  Further, in FIG. 2, the locking portion 63 has a structure protruding radially inward from the inner diameter of the quartz crucible 20, but is not limited to this, and the upper end of the quartz crucible 20 extends from the inner peripheral surface. It is also possible to form an inclination toward the outer side in the radial direction so as to coincide with the inner peripheral surface of the quartz crucible 20 as a combined structure. This makes it possible to reduce the adhesion of silicon evaporates to the top of the quartz crucible 20 (not shown). Further, the upper portion of the graphite crucible 21 can be fitted with the engaging portion 63 to prevent the quartz crucible 20 and the upper portion of the graphite crucible 21 from being displaced (not shown).

DESCRIPTION OF SYMBOLS 10 Single crystal silicon manufacturing apparatus 11 Chamber 20 Quartz crucible 21 Graphite crucible 60, 160, 260 Crucible opening holding member 63, 163, 263 Locking part

Claims (6)

A crucible opening holding member for preventing deformation of an opening of a quartz crucible in which silicon melt is stored,
The quartz crucible is made of a material having a higher temperature strength than that of the quartz crucible, and includes a locking portion that is locked to the inner peripheral surface of the side wall of the quartz crucible. A crucible opening holding member, characterized in that the crucible opening holding member is configured to be prevented from being deformed so as to collapse on the inner peripheral side.   The crucible opening holding member according to claim 1, wherein at least the locking portion is made of silicon carbide. A method for producing single crystal silicon in which a seed is immersed in a silicon melt stored in a quartz crucible disposed in a chamber, and the single crystal silicon is grown by pulling up the seed,
In the state where the crucible opening holding member according to claim 1 or 2 is attached to the quartz crucible, the single crystal silicon is pulled up,
A method for producing single crystal silicon, wherein the quartz crucible after use is reused after the pulling of the single crystal silicon is completed.   The method for producing single crystal silicon according to claim 3, wherein the quartz crucible is coated on the inner peripheral surface of the quartz crucible after use and then reused as a quartz crucible for storing a silicon melt. A single crystal silicon manufacturing apparatus in which a seed is immersed in a silicon melt stored in silicon in a quartz crucible disposed in a chamber, and the single crystal silicon is grown by pulling up the seed.
An apparatus for producing single crystal silicon, wherein the crucible opening holding member according to claim 1 or 2 is attached to the quartz crucible.   The quartz crucible is accommodated in a graphite crucible disposed in the chamber, the crucible opening holding member is disposed at the upper end of the graphite crucible, and the locking portion is an inner wall portion of the quartz crucible. The single crystal silicon manufacturing apparatus according to claim 5, wherein the single crystal silicon manufacturing apparatus is configured to be locked to a peripheral surface.

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