KR20120023488A

KR20120023488A - Apparatus and method for continuous casting of silicon ingot

Info

Publication number: KR20120023488A
Application number: KR1020100126876A
Authority: KR
Inventors: 타츠미 쿠사바
Original assignee: 가부시키가이샤 사무코
Priority date: 2010-08-12
Filing date: 2010-12-13
Publication date: 2012-03-13
Also published as: JP2012041197A

Abstract

It is used when continuously casting polycrystalline silicon by an electron casting method, has a conductive crucible and surrounds the bottomless cooling crucible 7 and the cooling crucible 7 which are continuously cast by dissolving a silicon raw material. In the continuous casting apparatus of the silicon ingot provided with the induction coil 8 which heats the silicon raw material charged in (7) by electromagnetic induction, and the chamber 1 which accommodates each said member, Inside the chamber 1 By arranging the wool material 17 on at least part of the wall surface and / or the surface of the member accommodated in the chamber 1, contamination by metal impurities in the wafer cut out from the ingot and the ingot being cast can be reduced. have. In the present invention, the wool material 17 is preferably made of alumina fibers, silica fibers or alumina silica fibers, and preferably has a density of 1 to 100 kg / m 3 and a thickness of 3 to 50 mm.

Description

Continuous casting device and continuous casting method of silicon ingot {APPARATUS AND METHOD FOR CONTINUOUS CASTING OF SILICON INGOT}

The present invention relates to a continuous casting apparatus and a continuous casting method of a silicon ingot which is a raw material of a solar cell substrate. More specifically, the present invention relates to a continuous casting apparatus and a continuous casting method of a silicon ingot capable of reducing contamination by metal impurities in an ingot to be cast and a wafer cut out from the ingot.

In recent years, the problem of global warming due to CO ₂ emission and the depletion of energy resources have become serious, and as one of countermeasures against such problems, solar power generation utilizing solar energy that is exposed to inexhaustible attention has been attracting attention. Photovoltaic power generation is a power generation system that converts solar energy directly into electric power using a solar cell, and a polycrystalline silicon wafer is mainly used as a substrate of the solar cell.

Polycrystalline silicon wafers for solar cells are manufactured by slicing this ingot using a unidirectional solidified silicon ingot as a material. For this reason, in order to spread the solar cell, it is necessary to secure the quality of the silicon wafer and to reduce the cost, and to manufacture the high quality silicon ingot at a low cost in the previous step. As a method which can respond to this request, for example, as disclosed in Patent Literature 1, the EMC method (Electromagnetic Casting method, electronic casting method), which is a continuous casting method using electromagnetic induction, has been put into practical use.

3 is a schematic view showing the configuration of a continuous casting apparatus (hereinafter, also simply referred to as "EMC furnace") used in the conventional EMC method. As shown in the figure, an EMC furnace includes a chamber 1. The chamber 1 is a double-walled water-cooled container that keeps the interior from outside air and is kept in an inert gas atmosphere suitable for casting. The raw material supply device which is not shown in figure is connected to the upper wall of the chamber 1 via the shutter 2 which can be opened and closed. In the chamber 1, an inert gas inlet 5 is formed in the upper side wall, and the exhaust port 6 is formed in the lower side wall. In addition, the inner wall surface of the chamber 1 is usually made of a metal such as stainless steel.

In the chamber 1, a bottomless cooling crucible 7, an induction coil 8, and an after heater 9 are arranged. The bottomless cooling crucible 7 consists of a metal cylinder (for example, copper) that is a rectangular cylinder and functions not only as a melting vessel but also as a mold, and is excellent in thermal conductivity and electrical conductivity. The cooling crucible 7 is divided into a plurality of single-piece small pieces in the circumferential direction leaving the upper portion, and forced cooling by the cooling water flowing through the inside. Such a cooling crucible 7 is usually fixed to a top plate 10, and the top plate 10 is fixed using a plurality of support rods 16 attached to the upper wall of the chamber 1. The top plate 10 is made of a metal such as stainless steel, and the cooling water supplied and discharged to the cooling crucible 7 is distributed therein.

The induction coil 8 is provided concentrically with the cooling crucible 7 so as to surround the cooling crucible 7, and is connected to the power supply device which is not shown in figure. The after-heater 9 is arranged below the cooling crucible 7 concentrically with the cooling crucible 7, and heats the silicon ingot 3 drawn down from the cooling crucible 7, and its axial direction. While cooling to room temperature over a long time while giving an appropriate temperature gradient. The after-heater 9 is usually comprised by the some heater which heats an ingot, the heat insulating material which insulates an ingot, and the metal member which fixes these.

Moreover, in the chamber 1, the raw material introduction pipe 11 is attached below the shutter 2 connected to the raw material supply apparatus. With opening / closing of the shutter 2, granular or blocky silicon raw material 12 is supplied into the raw material introduction pipe 11 from the raw material supply device and charged into the cooling crucible 7. .

In the bottom wall of the chamber 1, an outlet 4 for pulling out the ingot 3 is formed below the after heater 9, and the outlet 4 is sealed with gas. The ingot 3 is lowered while being supported by the support 15 descending through the outlet 4.

Immediately above the cooling crucible 7, the plasma torch 14 is formed to be liftable. The plasma torch 14 is connected to one pole of a plasma power supply device (not shown), and the other pole is connected to the ingot 3 side. The plasma torch 14 is lowered and inserted into the cooling crucible 7.

In the EMC method using such an EMC furnace, the silicon raw material 12 is charged inside the bottomless cooling crucible 7, an alternating current is applied to the induction coil 8, and the plasma torch 14 is lowered. Energize. At this time, since each piece of the single-shaped pieces constituting the cooling crucible 7 is electrically divided from each other, an eddy current is generated in each piece with the electromagnetic induction by the induction coil 8, and the cooling crucible 7 The eddy currents in the inner wall of the c) generate a magnetic field in the cooling crucible 7. Thereby, the silicon raw material 12 in the cooling crucible 7 is melted by electromagnetic induction heating, and the molten silicon 13 is formed. In addition, a plasma arc is generated between the plasma torch 14 and the silicon raw material 12, and further, the molten silicon 13, and the silicon raw material 12 is heated and melted by the Joule heat. The molten silicon 13 is efficiently formed by reducing the burden of electromagnetic induction heating.

The molten silicon 13 is formed by the interaction of a magnetic field generated with the eddy current of the inner wall of the cooling crucible 7 and a current generated on the surface of the molten silicon 13. Since a force (pinch force) is applied in the direction of the inner normal of the surface of the c), it is held in a non-contact state with the cooling crucible 7. Slowly lowering the support 15 supporting the molten silicon 13 while melting the silicon raw material 12 in the bottomless cooling crucible 7 results in an induction magnetic field as it moves away from the lower end of the induction coil 8. Since it becomes small, calorific value and pinch force decrease, and solidification advances from the outer periphery by the cooling from the cooling crucible 7 further. The molten silicon 13 solidifies in one direction and continuously casts the ingot 3 by continuously charging the silicon raw material 12 with the lowering of the support 15 and continuing melting and solidification. have.

According to this EMC method, contact between the molten silicon 13 and the bottomless cooling crucible 7 is reduced, so that contamination of impurities from the cooling crucible 7 accompanying the contact is prevented, and high-quality ingots 3) can be obtained. Moreover, since it is continuous casting, it becomes possible to manufacture the ingot 3 solidified in one direction at low cost.

International Publication WO02 / 053496 Brochure

In the continuous casting method of a silicon ingot by the EMC method using a conventional EMC furnace, when the wafer cut out from the cast silicon ingot is investigated by contamination of metal impurities by life time evaluation or total dissolution analysis, Fe Or metal impurities such as Ni, Cu, Cr are detected. Since contamination by metal impurities deteriorates photoelectric conversion efficiency when the wafer is used in a solar cell, it is desired to reduce contamination by metal impurities as much as possible in wafers cut out from the ingot and the ingot to be cast.

This invention is made | formed in view of such a situation, and it aims at providing the continuous casting apparatus and continuous casting method of the silicon ingot which can reduce the contamination by metal impurities in the ingot to be cast and the wafer cut out from an ingot. Doing.

MEANS TO SOLVE THE PROBLEM As a result of performing various tests and earnestly examining, the particle which generate | occur | produces when continuous casting of a silicon ingot by EMC method using an EMC furnace cuts the wafer cut out from the ingot and ingot cast as metal impurities. It was a contaminating factor.

4 (a) and 4 (b) are schematic diagrams showing a state in which particles generated when continuously casting a silicon ingot using a conventional continuous casting apparatus are suspended in a chamber, and FIG. 4 (a) shows generated particles. Is a state which floats in a chamber, and FIG.4 (b) shows the state which a particle mixes in a cooling crucible, respectively.

In continuous casting by the EMC method, when a silicon raw material charged into a cooling crucible is heated and dissolved by an induction coil and a plasma torch, a part of the silicon raw material is evaporated to become a vapor. As shown in FIG.4 (a), this vapor cools in the atmosphere in a chamber, becomes a particle | grain, and floats in the chamber. Particles floating in the chamber may come into contact with the inner wall surface of the chamber or the surface of a member such as a cooling crucible or an after heater housed in the chamber. Most of the floating particles fall and are deposited in the chamber, but some of the floating particles are incorporated into the cooling crucible as shown in Fig. 4B.

Here, since the inner wall of the chamber and the member housed in the chamber are made of stainless steel, copper, alumina, or carbon material, the particles suspended in the chamber come into contact with the inner wall surface of the chamber or the surface of the member housed in the chamber. Is contaminated with metal impurities such as Fe, Ni, Cu, and Cr. The present inventors have found that a wafer cut out from a cast ingot is a metal impurity as a result of particles floating in the chamber and contaminated with metal impurities in a cooling crucible and contaminating with a silicon raw material to contaminate the ingot to be cast with metal impurities. I thought it was contaminated.

MEANS TO SOLVE THE PROBLEM As a result of carrying out various tests and earnestly examining, the present inventors arrange | positioned the wool material on the inner wall surface of a chamber or the surface of the member accommodated in a chamber in the continuous casting apparatus used for EMC method. It has been recognized that the amount of particles floating in the chamber can be incorporated into the cooling crucible, thereby reducing the contamination of the cast ingot and the wafer cut out from the ingot with metallic impurities.

This invention is completed based on said recognition, and makes the summary the continuous casting apparatus of the silicon ingot of following (1)-(3), and the continuous casting method of the silicon ingot of following (4).

(1) Silicon which is used for continuous casting of polycrystalline silicon by an electron casting method, has a conductivity, and has a bottomless cooling crucible for dissolving and continuously casting a silicon raw material, and surrounding the cooling crucible and charged into the cooling crucible. In a continuous casting apparatus of a silicon ingot having an induction coil for heating a raw material by electromagnetic induction and a chamber for accommodating each member, at least part of an inner wall surface of the chamber and / or a surface of a member accommodated in the chamber. Continuous casting apparatus of a silicon ingot, characterized in that the wool material is arranged in the.

(2) The continuous casting apparatus of the silicon ingot according to the above (1), wherein the wool material is made of alumina fiber, silica fiber or alumina silica fiber.

(3) The continuous casting apparatus of the silicon ingot according to (1) or (2), wherein the wool member has a density of 1 to 100 kg / m 3 and a thickness of 3 to 50 mm.

(4) A continuous casting method of a silicon ingot, wherein the polycrystalline silicon is continuously cast by an electron casting method using the continuous casting apparatus of the silicon ingot according to any one of the above (1) to (3).

In the continuous casting apparatus and continuous casting method of the silicon ingot of the present invention, the particles contaminated with metallic impurities can be prevented from being mixed into the ingot to be cast by capturing particles floating in the chamber with a wool material. For this reason, the contamination by metal impurities can be reduced in the ingot to be cast and the wafer cut out from the ingot.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram explaining the continuous casting apparatus of the silicon ingot of this invention.
FIG. 2 is a view for explaining an example of a state in which a wool material captures particles suspended in a chamber in a continuous casting apparatus of a silicon ingot of the present invention.
It is a schematic diagram which shows the structure of the continuous casting apparatus used for the conventional EMC method.
4 (a) and 4 (b) are schematic diagrams showing a state in which particles generated when continuously casting a silicon ingot using a conventional continuous casting apparatus are suspended in a chamber. It is a state which floats in a chamber, and FIG.4 (b) shows the state which a particle mixes in a cooling crucible, respectively.
5 is a schematic diagram illustrating a position at which a silicon ingot is divided.
Fig. 6 is a diagram showing the life time values of wafers obtained by Examples and Comparative Examples of the present invention.
It is a figure which shows the Fe and Ni density | concentration in the wafer obtained by the example of this invention and a comparative example.

(Form to carry out invention)

EMBODIMENT OF THE INVENTION Below, the continuous casting apparatus and continuous casting method of the silicon ingot of this invention are demonstrated based on drawing.

1: is a schematic diagram explaining the continuous casting apparatus of the silicon ingot of this invention. The electroforming apparatus of this invention shown in the same figure is based on the structure of the continuous casting apparatus shown in said FIG. 3, The same code | symbol is attached | subjected to the same structure as that, and the overlapping description is abbreviate | omitted suitably. The continuous casting device shown in the same figure adds the wool material 17 to the continuous casting device described in FIG. 3.

The continuous casting apparatus of the silicon ingot of the present invention is used when continuously casting polycrystalline silicon by an electron casting method, has a conductivity, and has a bottomless cooling crucible 7 for melting and continuously casting a silicon raw material, and a cooling crucible. In the continuous casting apparatus of the silicon ingot having an induction coil 8 for heating the silicon raw material charged into the cooling crucible by electromagnetic induction and a chamber 1 for accommodating each member, the inner wall surface of the chamber And / or disposing the wool material 17 on at least a portion of the surface of the member contained in the chamber.

By arranging the wool material 17 having a fibrous structure on at least part of the inner wall surface of the chamber and / or the surface of the member accommodated in the chamber, a part of the particles floating in the chamber is captured by the wool material.

FIG. 2 is a view for explaining an example of a state in which a wool material captures particles floating in a chamber in a continuous casting apparatus of a silicon ingot of the present invention. In the same figure, the side wall surface in the inner wall surface of the chamber 1 and the wool material 17 arrange | positioned at the side wall surface are shown. Part of the particles 18 floating in the chamber enters into the fiber structure of the wool material 17 and is captured as shown in the figure. Since the particles 18 of the wool material 17 are wound around the particles 18 trapped by the wool material 17, they are difficult to be swept away by the atmosphere flow in the chamber and are difficult to float again.

Particularly, particles having a particle diameter of 1 µm or less require time from being suspended to falling and deposited, since they are difficult to fall. In addition, particles having a particle diameter of 1 μm or less are likely to float again by the flow of the atmosphere in the chamber even when they are dropped and deposited. The wool material can capture particles having a particle diameter of 1 μm or less, and the particles having a particle size of 1 μm or less are difficult to float again because the fibers of the wool material 17 are wound.

In this way, by the wool material disposed on the inner wall surface of the chamber and / or the surface of the member accommodated in the chamber, the particles floating in the chamber can be captured, thereby reducing the amount of particles floating in the chamber. For this reason, the continuous casting apparatus of the silicon ingot of the present invention can reduce the amount of particles suspended in the chamber and contaminated with metal impurities in the cooling crucible, so that the wafer cut out from the ingot and the ingot being cast can be replaced with metal impurities. Contamination can be reduced.

The wool material is preferably disposed in more areas of the inner wall surface of the chamber, so long as it does not interfere with continuous casting. Since particles floating in the chamber are swept to all positions in the chamber by the atmospheric flow, the amount of particles trapped by the wool increases as the area where the wool is disposed on the inner wall surface of the chamber increases. For this reason, by arrange | positioning a wool material in more area | regions, it is possible to further reduce the quantity of the particle | grains which float in a chamber, and to reduce the contamination by metal impurities in the ingot to be cast and the wafer cut out from an ingot further.

In addition, it is preferable that the wool member is disposed in more regions of the surface of the member accommodated in the chamber, so long as it does not interfere with continuous casting. Since the particles floating in the chamber also come into contact with the member contained in the chamber, the amount of particles trapped by the wool increases as the wool is disposed in more regions of the surface of the member contained in the chamber. This is because the amount of particles suspended in the chamber can be further reduced, and contamination of metal impurities with the ingot to be cast and the wafer cut out from the ingot can be further reduced.

Specifically, as shown in FIG. 1, a wool member can be disposed on the inner wall surface and the side wall surface of the chamber 1, and the surface of the member accommodated in the chamber is surrounded by an induction coil 8. This can be arranged in the outer circumferential surface of the cooling crucible (7), the upper surface and the outer circumferential surface of the after-heater 9, the upper surface of the top plate 10 and the outer circumferential surface of the support bar (16) except for the portion.

As a method of arranging a wool material on the inner wall surface of a chamber or the surface of the member accommodated in a chamber, various methods conventionally used can be employ | adopted, For example, it is a sheet shape using a heat-resistant binding band. It is possible to tie the wool material, or to hang the sheet-shaped wool material on the hook formed on the inner wall surface of the chamber.

It is preferable that the wool member does not contain metal impurities that cause contamination at the point of being accommodated in the chamber, and has heat resistance at the point of becoming high temperature during continuous casting. In addition, since the wool material captures and holds particles contaminated with metallic impurities, it is necessary to replace the ingot every time the continuous casting is carried out or periodically, and it is preferable that the wool material is low in cost. For this reason, it is preferable that the continuous casting apparatus of the silicon ingot of this invention uses what consists of alumina fiber, a silica fiber, or an alumina silica fiber as a wool material. By using the wool material which consists of alumina fiber, a silica fiber, or an alumina silica fiber, the concern about the contamination, heat resistance, and cost by the above-mentioned metal impurity can be eliminated.

It is preferable to use a wool material having a density of 1 to 100 kg / m 3 and a thickness of 3 to 50 mm. If the density of the wool material exceeds 100 kg / m 3, suspended particles cannot penetrate to the inner depth of the fiber structure, and the particles are only captured in the vicinity of the wool material surface, thereby reducing the amount of particles that can be captured by the wool material. . For this reason, the effect of reducing the contamination by metal impurities in the ingot to be cast and the wafer cut out from the ingot may be weakened.

On the other hand, if the density of the wool material is less than 1 kg / m 3, the amount of particles that can be trapped and retained by the wool material is insufficient because the entrainment of the fibers of the wool material into the trapped particles is insufficient and the trapped particles are likely to float again. This decreases. For this reason, the effect of reducing the contamination by metal impurities in the ingot to be cast and the wafer cut out from the ingot may be weakened. As for the density of a wool material, 2-60 kg / m <3> is more preferable.

If the thickness of the wool material exceeds 50 mm, handling becomes difficult, and workability falls when arrange | positioning or replacing a wool material on the inner wall surface of a chamber or the surface of the member accommodated in a chamber. On the other hand, when the thickness of the wool material is less than 3 mm, the amount of particles that can be captured by the wool material decreases, and there is a concern that contamination by metal impurities in the ingot and the wafer cut out from the ingot cannot be reduced. As for the thickness of a wool material, 5-20 mm is more preferable.

The amount of particles captured by the wool member disposed on the inner wall surface of the chamber or the surface of the member accommodated in the chamber varies depending on the position in the chamber. For example, in the continuous casting device shown in FIG. 1, the inner wall surface of the chamber located above the cooling crucible 7 in which most of the particles are generated, the upper surface of the top plate 10, and the outer peripheral surface of the support rod 16 are disposed. The resultant wool material captures a large amount of particles as compared with the wool material disposed on the inner wall surface of the chamber located below the cooling crucible and the outer circumferential surface of the after heater 9.

This is because most of the particles are generated in the upper part of the cooling crucible and float in the chamber above the cooling crucible, and part of it is swept into the atmosphere flow to float in the chamber below the cooling crucible. For this reason, the amount of particles floating in the chamber above the cooling crucible becomes larger than the amount of particles floating in the chamber below the cooling crucible.

Therefore, it is preferable that the continuous casting apparatus of the silicon ingot of this invention adjusts the density and thickness of a wool material for every position according to the quantity of the particle | grains captured by the position arrange | positioned. For example, in the continuous casting device shown in FIG. 1, the thickness of the wool material disposed on the inner wall surface of the chamber located above the cooling crucible 7, the upper surface of the top plate 10, and the outer peripheral surface of the support bar 16, The thickness is thicker than that of the wool disposed on the inner wall surface of the chamber located below the cooling crucible and the outer circumferential surface of the after heater 9. Thereby, the quantity of the wool material arrange | positioned can be suppressed and the particle | grains floating in a chamber can be captured effectively.

The continuous casting method of the silicon ingot of the present invention is characterized by continuously casting polycrystalline silicon by the electronic casting method using the above-described continuous casting device of the present invention. For this reason, in the continuous casting method of the silicon ingot of the present invention, since the particles floating in the chamber can be captured by the wool material and the amount of particles floating in the chamber can be reduced, the metal impurities are suspended in the chamber. The amount of contaminated particles incorporating into the cooling crucible is reduced.

Therefore, the continuous casting method of the silicon ingot of the present invention can reduce the contamination of the ingot formed by melting and solidifying the particles contaminated with the metal impurities with the silicon raw material with the metal impurities, and as a result, from the cast ingot In the cut out wafer, contamination by metal impurities can be reduced.

(Example)

In order to confirm the effect of the continuous casting apparatus and continuous casting method of the silicon ingot of this invention, the following test was done.

[Exam conditions]

In this test, the silicon ingot which consists of a cut length of 7000 mm was continuously cast by the EMC method using the continuous casting apparatus shown in the said FIG. In the continuous casting apparatus used for this test, as shown in the said FIG. 1, while arrange | positioning a wool material in the upper wall surface and the side wall surface among the inner wall surfaces of the chamber 1, cooling except the part enclosed by the induction coil 8 is carried out. Wool material was arrange | positioned on the outer peripheral surface of the crucible 7, the upper surface and outer peripheral surface of the after heater 9, the upper surface of the top plate 10, and the outer peripheral surface of the support rod 16.

In Example 1 of the present invention, a wool material having a density of 10 kg / m 3 and a thickness of 10 mm was formed of alumina silica fibers. In Example 2 of the present invention, a wool material having a density of 5 kg / m 3 and a thickness of 20 mm was formed of alumina silica fibers. In the comparative example, the silicon ingot was continuously cast by the EMC method using the continuous casting apparatus shown in FIG. 3 without arranging a wool material on the inner wall surface of the chamber and the surface of the member accommodated in the chamber. In the present invention and the comparative example, the cast ingot was cut to remove the main surface, and then the ingot was cut and divided.

5 is a schematic diagram illustrating a position at which a silicon ingot is divided. As shown to the same figure, the silicon ingot 3 was divided into two lengthwise and three horizontally in the plane parallel to a reduction axis, and it was set as six division ingot 31 which makes the reduction axis direction the longitudinal direction. Both the invention example and the comparative example cut out the wafer from the division ingot 31 of which the diagonal line was drawn.

The wafers cut out of the examples of the present invention and the comparative examples were each measured for life time values, and the concentrations of Fe and Ni were measured by total solution analysis to investigate contamination by metal impurities. In the measurement of the lifetime value, the surface damage layer was etched with hydrofluoric acid on the cut wafer, and then the surface oxide film was removed with buffered hydrofluoric acid (BHF). In addition, after chemical passivation of the wafer surface with iodine, the lifetime value of the wafer surface was measured by the μ-PCD method.

[Test result]

Fig. 6 is a diagram showing the life time values of wafers obtained by Examples and Comparative Examples of the present invention. In the same figure, a life time value is shown by the relative value which made the comparative example the reference | standard (1.0). From the results shown in the same drawings, in Examples 1 and 2 of the present invention, the lifetime value was increased in comparison with the comparative example, and it was confirmed that contamination by metal impurities in the wafer cut out from the cast ingot was reduced.

FIG. 7: is a figure which shows Fe and Ni density | concentration in the wafer obtained by the example of this invention, and a comparative example. In the same figure, the relative value which made Fe and Ni concentration the comparative example the reference | standard (1.0) is shown. From the results shown in the same drawings, in Examples 1 and 2 of the present invention, it was confirmed that the Fe and Ni concentrations were lower than those of the comparative examples, and that contamination by metal impurities in the wafer cut out from the cast ingot was reduced.

From these, it became clear that the continuous casting apparatus of the silicon ingot of this invention and the continuous casting method using the same can reduce the contamination by metal impurities in the wafer cut out from the cast ingot by arrange | positioning a wool material.

Therefore, if the continuous casting apparatus and continuous casting method of the silicon ingot of this invention are applied to manufacture of the wafer for solar cells, it can contribute greatly to the quality improvement of a solar cell.

1: chamber
2: shutter
3: silicon ingot
4: outlet
5: inert gas inlet
6: exhaust port
7: floorless cooling crucible
8: induction coil
9: after heater
10: top plate
11: raw material introduction pipe
12: silicon raw material
13: molten silicon
14: plasma torch
15: support
16: support rod
17: wool ash
18: particle
31: Split Ingot

Claims

Silicon which is used for continuous casting of polycrystalline silicon by an electron casting method, has a conductivity, and has a bottomless cooling crucible for dissolving and continuously casting a silicon raw material, and surrounding the cooling crucible and charged into the cooling crucible. In the continuous casting device of the silicon ingot provided with an induction coil for heating the raw material by electromagnetic induction, and a chamber for accommodating each member,
A wool material is disposed on at least a portion of either or both of an inner wall surface of the chamber and a surface of a member accommodated in the chamber.

The method of claim 1,
A continuous casting apparatus for a silicon ingot, wherein the wool material is made of alumina fiber, silica fiber or alumina silica fiber.

The method according to claim 1 or 2,
The wool material is a continuous casting device of silicon ingot, characterized in that the density is 1 ~ 100kg / ㎥ and thickness is 3 ~ 50mm.

A continuous casting method of a silicon ingot, using the continuous casting device of the silicon ingot according to claim 1 or 2, by continuously casting polycrystalline silicon.

Using the continuous casting apparatus of the silicon ingot of Claim 3, polycrystalline silicon is cast continuously by the electronic casting method, The continuous casting method of the silicon ingot characterized by the above-mentioned.