JP2011057470A - Apparatus and method for producing single crystal silicon - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for producing single crystal silicon where heat from a heater is efficiently applied to a crucible when melting a silicon raw material and holding a silicon melt, where heat around the crucible is radiated when cooling the surroundings of the crucible and where the shortening of the producing cycle time of the single crystal silicon and the reduction of an electric power cost are aimed. <P>SOLUTION: The apparatus 10 for producing the single crystal silicon where a seed S is immersed in the silicon melt M stored in the crucible 20 located in a chamber 11 and pulled up and then the single crystal silicon T is grown, includes a heat insulating cylinder 50 surrounding the outer peripheral side of the crucible 20 and a heater 40 set on the inner peripheral side of the heat insulating cylinder 50, wherein a reflecting plate 52 to reflect heat and a reflective plate exposing area regulating means 53 to regulate the exposing area of the reflecting plate 52 are located in the heat insulating cylinder 50. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a single crystal silicon manufacturing apparatus and a single crystal silicon manufacturing method in which a seed is immersed in a silicon melt stored in a crucible and the seed is pulled to grow single crystal silicon.

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 Document 1, polycrystalline silicon is placed in a quartz crucible placed in a high pressure-tight airtight chamber, the polycrystalline silicon in the quartz crucible is heated and melted, and a quartz crucible is obtained. A seed (seed crystal) is attached to a seed chuck disposed above the substrate, and the seed is immersed in a silicon melt in a quartz crucible, and the seed is pulled up while rotating the seed and the quartz crucible to grow single crystal silicon. It has become.

  In the above-described method for producing single crystal silicon, it is necessary to melt a silicon raw material contained in a quartz crucible to produce a silicon melt and to keep the silicon melt warm. Power costs for tend to increase. Further, in order to increase the production amount of single crystal silicon, it is necessary to shorten the melting time. For this reason, for example, Patent Document 2 proposes a heat insulating material disposed around a quartz crucible.

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

  However, as described in Patent Document 2, even when a heat insulating material is provided around the crucible, heat from the heater is dissipated to the outside through the heat insulating material. Thus, it was not possible to effectively shorten the length, and it was not possible to increase the production amount of single crystal silicon. For this reason, the further heat retention improvement is calculated | required so that the heat of a heater may not dissipate outside.

  On the other hand, after the pulling of the single crystal silicon is completed, it is necessary to cool the periphery of the crucible in order to replace the crucible or to insert the silicon raw material. For this reason, for example, in the case where the heat insulating property of the heat insulating material is improved in order to improve the heat retaining property, the time required for cooling will be greatly increased, and eventually the production amount of single crystal silicon will be increased. There was a problem that it was impossible.

  The present invention has been made in view of the above-described circumstances, and when the silicon raw material is melted and the silicon melt is held, the heat of the heater is efficiently applied to the crucible, and the periphery of the crucible is cooled. Provides a single-crystal silicon manufacturing apparatus and a single-crystal silicon manufacturing method capable of efficiently dissipating the heat around the crucible, reducing the manufacturing cycle time of single-crystal silicon, and reducing power costs. The purpose is to provide.

  In order to solve the above-described problems, the single crystal silicon manufacturing apparatus of the present invention immerses a seed in a silicon melt stored in a crucible disposed in a chamber, and raises the seed to grow single crystal silicon. An apparatus for producing single crystal silicon, comprising: a heat retaining cylinder portion that surrounds the outer peripheral side of the crucible; and a heater provided inside the heat retaining cylinder portion, and an inner peripheral surface of the heat retaining cylinder portion Is characterized in that a reflecting plate for reflecting heat and a reflecting plate exposed area adjusting means for adjusting the exposed area of the reflecting plate are provided.

  According to the single crystal silicon manufacturing apparatus of this configuration, the reflection plate that reflects heat and the reflection plate exposure area adjustment unit that adjusts the exposure area of the reflection plate are provided on the inner peripheral surface of the heat insulating cylinder portion. Therefore, when the heat of the heater provided inside the heat insulation cylinder part is applied to the crucible, such as when the silicon raw material is melted or when the silicon melt is held, the exposed area of the reflector is increased. The heat from the heater can be reflected by the reflector and act on the crucible, so that the melting time of the silicon raw material can be shortened and the power cost can be reduced as compared with the case where a heat insulating material is simply provided.

On the other hand, when the periphery of the crucible is cooled, by reducing the exposed area of the reflecting plate, the heat around the crucible can be prevented from being reflected by the reflecting plate, and the heat is dissipated to the outside of the heat insulating cylinder. It becomes possible.
Accordingly, it is possible to shorten both the melting time of the silicon raw material and the cooling time around the crucible, the production cycle time of the single crystal silicon can be greatly shortened, and the production amount of the single crystal silicon can be increased. it can.

Here, it is preferable that the reflection plate exposure area adjusting means is a shutter member that is stacked on the crucible side of the reflection plate and adjusts the exposure area of the reflection plate by sliding.
In this case, it is possible to easily and reliably adjust the exposed area of the reflecting plate by slidingly moving the shutter members arranged in layers on the crucible side of the reflecting plate.

In addition, a second reflector that reflects heat from the bottom of the crucible and a second reflector exposure area adjustment unit that adjusts an exposure area of the second reflector are provided below the heat retaining cylinder. Are preferably provided.
In this case, by reflecting the heat by the second reflector, heat dissipation from the bottom of the crucible can be prevented, and the melting time of the silicon raw material can be shortened and the power cost can be reduced. In addition, when cooling the crucible area, the exposed area of the second reflector is reduced to prevent the heat around the crucible from being reflected by the second reflector, thereby promoting heat dissipation. It is possible to shorten the cooling time around the crucible.

  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 crucible disposed in a chamber, and the seed is pulled to grow single crystal silicon. When the silicon raw material contained in the crucible is melted using the single crystal silicon manufacturing apparatus, the exposure area of the reflection plate is set large by the reflection plate exposure area adjusting means, When the periphery of the crucible is cooled after the pulling of the crystalline silicon is finished, the exposed area of the reflecting plate is set to be small by the reflecting plate exposed area adjusting means.

  According to the method for producing single crystal silicon having this configuration, when the silicon raw material housed in the crucible is melted, the reflecting plate exposed area adjusting means sets the exposed area of the reflecting plate to be large, and the single crystal When the periphery of the crucible is cooled after the pulling of silicon is finished, the exposure area of the reflector is set small by the reflector exposure area adjusting means, so that both the melting time of the silicon raw material and the cooling time around the crucible are both Thus, the manufacturing cycle time of single crystal silicon can be greatly shortened, and the production amount of single crystal silicon can be increased.

  According to the present invention, when the silicon raw material is melted and when the silicon melt is held, the heat of the heater is efficiently applied to the crucible, and when the periphery of the crucible is cooled, the heat around the crucible is efficiently dissipated. It is possible to provide a single crystal silicon manufacturing apparatus and a single crystal silicon manufacturing method capable of reducing the manufacturing cycle time of single crystal silicon and reducing the power cost.

It is explanatory drawing which shows the manufacturing apparatus of the single crystal silicon which is embodiment of this invention. It is a schematic explanatory drawing of the heat insulation cylinder part with which the single crystal silicon manufacturing apparatus shown in FIG. 1 was equipped. It is a schematic explanatory drawing which shows the open state of the 1st shutter member with which the single crystal silicon manufacturing apparatus shown in FIG. 1 was equipped. It is a schematic explanatory drawing which shows the closed state of the 1st shutter member with which the single crystal silicon manufacturing apparatus shown in FIG. 1 was equipped. FIG. 4 is a top view of the first reflector and the first shutter member shown in FIG. 3. FIG. 5 is a top view of the first reflector and the first shutter member shown in FIG. 4. It is explanatory drawing which shows the open state of the 2nd shutter member with which the manufacturing apparatus of the single crystal silicon shown in FIG. It is explanatory drawing which shows the closed state of the 2nd shutter member with which the single crystal silicon manufacturing apparatus shown in FIG. 1 was equipped.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
In the single crystal silicon manufacturing apparatus 10 according to the present embodiment, as 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, and the quartz crucible 20 are provided. A crucible support base 22 for supporting, a heater 40 for heating the quartz crucible 20, a heat retaining cylinder portion 50 surrounding the quartz crucible 20, a seed chuck 27 for holding a seed crystal (seed), and the seed chuck 27 And a seed chuck drive mechanism 30 for driving.

  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.

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 quartz crucible 20 can hold massive polycrystalline silicon (silicon raw material), which is a raw material of the single crystal silicon T, in the recess, and can store a silicon melt M generated by heating and melting the polycrystalline silicon. Has been. Here, the quartz crucible 20 is housed in a graphite susceptor 21.
The graphite susceptor 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.

Further, a cylindrical heater 40 around the graphite susceptor 21 and a cylindrical heat retaining member sandwiched vertically by a disk-like lower ring 45 and a disk-like upper ring 46 outside the heater 40. A cylindrical portion 50 is disposed.
The lower portion of the heater 40 is fixed to the electrode joint 41 with bolts 42, and the electrode joint 41 is connected to a power source (not shown) through a graphite electrode 43 disposed in a through hole formed in the spill tray 16.
Further, a flow pipe 48 is attached to the upper end of the heat retaining cylinder portion 50 via an upper ring 46 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.

As shown in FIG. 2, the heat insulation cylinder portion 50 includes a heat insulation cylinder main body 51 made of cylindrical porous graphite, a first reflecting plate 52 positioned on the inner peripheral side of the heat insulation cylinder main body 51, and the first reflection. And a first shutter member 53 that adjusts the exposed area of the plate 52.
The first reflecting plate 52 is made of, for example, a stainless steel plate having metallic luster, and is configured to reflect the heat on the inner peripheral side of the heat retaining cylinder portion 50.
The first shutter member 53 has a double structure as shown in FIG. 5 and FIG. 6. The first shutter member 53 has a fixed cylinder 54 disposed on the outer peripheral side, and is laminated on the inner peripheral side of the fixed cylinder 54. And a slide cylinder 55 that is slidably movable relative to 54. The exposed area of the first reflecting plate 52 is adjusted by sliding the slide cylinder 55 with respect to the fixed cylinder 54.

Further, below the inner peripheral side of the heat retaining cylinder portion 50, as shown in FIG. 1, a second reflecting plate 62 having a disc shape and a second shutter for adjusting the exposed area of the second reflecting plate 62 are provided. A member 63 is disposed. The second reflection plate 62 and the second shutter member 63 are stacked and arranged so as to extend in a direction orthogonal to the support shaft 23 (axis line O) of the crucible support base 22. The second reflector 62 is disposed so as to face the bottom of the quartz crucible 20.
The second shutter member 63 includes a fixed plate 64 and a slide plate 65 stacked on the fixed plate 64, and the second shutter member 63 slides relative to the fixed plate 64 to move the second shutter member 63. The exposed area of the reflecting plate 62 is adjusted.

Next, a method for manufacturing single crystal silicon using the single crystal silicon manufacturing apparatus 10 will be described.
First, bulk polycrystalline silicon as a raw material is filled in the quartz crucible 20, and the quartz crucible 20 is heated by a heater 40 to dissolve the polycrystalline silicon to form a silicon melt M at 1420 ° C., and the seed S is immersed therein. The silicon melt M in the vicinity of the portion is brought into a supercooled state.
At this time, as shown in FIGS. 3 and 5, the first shutter member 53 is arranged so that the slide cylinder 55 is laminated on the inner peripheral side of the fixed cylinder 54, and the exposed area of the first reflecting plate 52 is large. Is set. Further, as shown in FIG. 7, the second shutter member 63 is arranged such that the slide plate 65 is positioned on the fixed plate 64, and the exposed area of the second reflecting plate 62 is set large.

Next, the seed S is inserted and fixed in the carbon chuck portion 28, the seed chuck driving 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 silicon. Apply to liquid M.
Then, when the seed S becomes familiar with the silicon melt M, the seed chuck 27 is raised at a speed of 0.5 mm / min to 7.0 mm / min while rotating the seed chuck 27 clockwise, for example, at 5 rpm to 15 rpm.
At this time, the quartz crucible 20 is rotated counterclockwise in plan view at, for example, 0.2 rpm to 6.0 rpm.

  By pulling up the seed S and depositing the single crystal silicon T in this way, the single crystal silicon T having a circular cross section is grown.

After the pulling of the single crystal silicon T is completed, the temperature in the chamber 11 is lowered in order to take out the single crystal silicon T and prepare for the production of the next single crystal silicon.
At this time, as shown in FIGS. 4 and 6, the first shutter member 53 is moved by sliding the slide cylinder 55 arranged on the inner peripheral side of the fixed cylinder 54, so that the exposed area of the first reflector 52 is exposed. Is set smaller. Further, as shown in FIG. 8, the second shutter member 63 is configured such that the slide plate 65 disposed on the fixed plate 64 is slid and the exposed area of the second reflecting plate 62 is set small. .

  According to the single crystal silicon manufacturing apparatus 10 and the single crystal silicon manufacturing method of the present embodiment configured as described above, the first reflecting plate 52 made of a stainless steel plate is provided on the inner peripheral surface of the heat insulating cylinder portion 50. And the first shutter member 53 for adjusting the exposed area of the first reflector 52, the first shutter member 53 for adjusting the exposed area of the first reflecting plate 52 is used when the polycrystalline silicon (silicon raw material) charged in the quartz crucible 20 is melted. By increasing the exposed area of one reflector 52, the heat from the heater 40 can be reflected by the first reflector 52 and applied to the quartz crucible 20, and the melting time of polycrystalline silicon (silicon raw material) can be reduced. It can be greatly shortened.

In addition, after the pulling of the single crystal silicon T is finished, the first periphery is cooled when the periphery of the quartz crucible 20, that is, the inner peripheral side portion of the heat retaining cylinder portion 50, in preparation for the production of the next single crystal silicon. By reducing the exposed area of the first reflecting plate 52 by the shutter member 53, it is possible to prevent the heat around the quartz crucible 30 (the inner peripheral side portion of the heat retaining cylinder portion 50) from being reflected by the first reflecting plate 52, Heat can be efficiently dissipated to the outside of the heat insulating cylinder portion 50.
Therefore, both the melting time of polycrystalline silicon (silicon raw material) and the cooling time around the quartz crucible 20 can be shortened, and the manufacturing cycle time of the single crystal silicon T can be greatly shortened. The production amount of T can be increased.

  Even when the silicon melt M is held and the single crystal silicon T is pulled up, the exposed area of the first reflecting plate 52 is increased so that the heat from the heater 40 is transferred by the first reflecting plate 52. By reflecting, the temperature of the quartz crucible 20 can be maintained, and the power cost can be reduced. Thus, by reflecting heat by the first reflecting plate 52, the power cost required for melting the polycrystalline silicon (silicon raw material) and holding the silicon melt M can be greatly reduced.

  In addition, a second reflecting plate 62 that reflects heat and a second shutter member 63 that adjusts the exposed area of the second reflecting plate 62 are provided below the inner peripheral side of the heat retaining cylinder portion 50. The second reflector 62 can reflect the heat dissipated from the bottom side of the quartz crucible 20, and can shorten the melting time of polycrystalline silicon (silicon raw material) and the power cost. On the other hand, when the periphery of the quartz crucible 20 is cooled, the heat dissipation from the bottom side of the quartz crucible 20 can be promoted by reducing the exposed area of the second reflecting plate 62, It is possible to shorten the cooling time.

As mentioned above, although the manufacturing apparatus and manufacturing method of the single crystal silicon which are one Embodiment of this invention were demonstrated, this invention is not limited to this, In the range which does not deviate from the technical idea of the invention, it can change suitably. It is.
For example, the first reflecting plate and the second reflecting plate have been described as being made of a stainless steel plate, but the present invention is not limited thereto, and any other metal plate or the like that reflects heat can be used. In particular, a molybdenum (Mo) plate or a tantalum (Ta) plate is suitable as a reflecting plate because of its good heat resistance.

Moreover, although it demonstrated as what adjusts the exposed area of a 1st reflecting plate and a 2nd reflecting plate with the 1st shutter member and 2nd shutter member which slide, and moves, it is not limited to this, For example, a reflecting plate Other structures such as adjusting the exposure area by driving itself may be used.
Furthermore, 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 may be appropriately changed in design.

10 Monocrystalline silicon production equipment 11 Chamber (airtight chamber)
20 Quartz crucible
40 Heating heater 50 Insulating cylinder portion 52 First reflector (reflector)
53 1st shutter member (shutter member / reflecting plate exposure area adjusting means)
62 Second reflector (second reflector)
63 Second shutter member (shutter member / second reflecting plate exposure area adjusting means)

Claims (4)

A device for producing single crystal silicon in which a seed is immersed in a silicon melt stored in a crucible arranged in a chamber, and the seed is pulled to grow single crystal silicon,
A heat insulating cylinder portion surrounding the outer peripheral side of the crucible, and a heater provided on the inner peripheral side of the heat insulating cylinder portion,
The apparatus for producing single crystal silicon, wherein the heat insulating cylinder portion is provided with a reflecting plate for reflecting heat and a reflecting plate exposed area adjusting means for adjusting an exposed area of the reflecting plate.   The said reflecting plate exposure area adjustment means is a shutter member which is laminated and arrange | positioned at the said crucible side of the said reflecting plate, and adjusts the exposure area of the said reflecting plate by sliding movement. Single crystal silicon manufacturing equipment.   At the lower part of the heat insulating cylinder part, there are a second reflecting plate that reflects heat from the bottom of the crucible, and a second reflecting plate exposed area adjusting means that adjusts the exposed area of the second reflecting plate. The single crystal silicon manufacturing apparatus according to claim 1, wherein the single crystal silicon manufacturing apparatus is provided. A method for producing single crystal silicon in which a seed is immersed in a silicon melt stored in a crucible disposed in a chamber, and the single crystal silicon is grown by pulling up the seed,
When melting the silicon raw material accommodated in the crucible using the above-described single crystal silicon manufacturing apparatus, the exposed area of the reflecting plate is set large by the reflecting plate exposed area adjusting means,
The method for producing single crystal silicon, wherein when the periphery of the crucible is cooled after the pulling of the single crystal silicon is finished, the exposed area of the reflecting plate is set small by the reflecting plate exposed area adjusting means.

Images