KR20120021134A - Apparatus for electromagnetic casting of silicon ingot - Google Patents

Apparatus for electromagnetic casting of silicon ingot Download PDF

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Publication number
KR20120021134A
KR20120021134A KR1020100126879A KR20100126879A KR20120021134A KR 20120021134 A KR20120021134 A KR 20120021134A KR 1020100126879 A KR1020100126879 A KR 1020100126879A KR 20100126879 A KR20100126879 A KR 20100126879A KR 20120021134 A KR20120021134 A KR 20120021134A
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South Korea
Prior art keywords
heater
silicon
silicon ingot
cooling crucible
ingot
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KR1020100126879A
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Korean (ko)
Inventor
타츠미 쿠사바
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가부시키가이샤 사무코
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Publication of KR20120021134A publication Critical patent/KR20120021134A/en

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    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/02—Elements
    • C30B29/06—Silicon
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B35/00—Apparatus not otherwise provided for, specially adapted for the growth, production or after-treatment of single crystals or of a homogeneous polycrystalline material with defined structure
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B35/00—Apparatus not otherwise provided for, specially adapted for the growth, production or after-treatment of single crystals or of a homogeneous polycrystalline material with defined structure
    • C30B35/002—Crucibles or containers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Silicon Compounds (AREA)

Abstract

(Problem) A silicon ingot capable of suppressing contamination of molten silicon with metallic impurities due to an atmospheric gas rising between the inner circumferential surface of the after-heater and the outer circumferential surface of the ingot during continuous casting by the electron casting method. Provides an electronic casting device.
(Solution means) The silicon raw material 11 is charged into the bottomless cooling crucible 7 arranged in the chamber 1, and the silicon raw material 11 is formed by electromagnetic induction heating from the induction coil 8. Is melted and solidified while lowering the molten silicon 12 from the cooling crucible 7 to continuously cast the silicon ingot 3, wherein the silicon ingot 3 is located below the cooling crucible 7. In this order, the carbon heat insulation heater 9a and the metal crack heater 9b are arrange | positioned in this order, and the whole periphery is carried out on the outer peripheral surface of the silicon ingot 3 between the heat insulation heater 9a and the crack heater 9b. It is provided with the heat-resistant nonwoven fabric 20 which contacts over and divides the clearance gap between the inner peripheral surface of each heater 9a, 9b, and the outer peripheral surface of the silicon ingot 3 up and down.

Description

Electronic casting device of silicon ingot {APPARATUS FOR ELECTROMAGNETIC CASTING OF SILICON INGOT}

The present invention relates to an electronic casting device for continuously casting a silicon ingot which is a raw material of a solar cell substrate.

As a substrate of a solar cell, it is mainstream to use a polycrystalline silicon wafer. The polycrystalline silicon wafer is manufactured by slicing this ingot using a silicon ingot of one-way solidification as a material. Therefore, in order to spread the solar cell, it is necessary to secure the quality of the silicon wafer and to reduce the cost. Therefore, in the previous step, it is required to manufacture the silicon ingot with high quality and low cost. As a method which can respond to this request, for example, as disclosed in Patent Literature 1, a continuous casting method using the electromagnetic induction (hereinafter also referred to as an "electronic casting method") has been put into practical use.

4 is a diagram schematically illustrating a configuration of a conventional representative electronic casting apparatus used in the electronic casting method. As shown in the figure, the electronic casting apparatus includes a chamber 1. The chamber 1 is a water-cooled container of a double wall structure which isolates the inside from outside air and maintains it in an inert gas atmosphere suitable for casting. The raw material supply hopper 2 is connected to the upper wall of the chamber 1. In the chamber 1, an inert gas inlet 5 is formed at an upper portion, and an exhaust port 6 is formed at a lower side wall.

In the chamber 1, a bottomless cooling crucible 7, an induction coil 8, and an after heater 9 are arranged. The cooling crucible 7 functions not only as a melting vessel but also as a mold, and is suspended in the chamber 1 as a cylindrical body made of a metal (for example, copper) having excellent thermal conductivity and conductivity. The cooling crucible 7 is formed with a plurality of slits not shown in the vertical direction leaving the upper part and the lower part, and the slits are divided into a plurality of single-piece small pieces in the circumferential direction. Forced cooling by the cooling water flowing through the inside.

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 provided below the cooling crucible 7 concentrically with the cooling crucible 7 in multiple numbers, and surrounds the silicon ingot 3 pulled off from the cooling crucible 7. The after-heater 9 is comprised from the thermal insulation heater 9a and the crack heater 9b in order from upper direction close to the cooling crucible 7, heats the silicon ingot 3, and provides the appropriate temperature gradient in the axial direction. Grant.

In the chamber 1, a raw material introduction pipe 10 is disposed below the raw material supply hopper 2. Granular or bulk silicon raw material 11 is supplied from the raw material supply hopper 2 to the raw material introduction pipe 10, and charged into the cooling crucible 7 through the raw material introduction pipe 10. (裝入) becomes.

In the bottom wall of the chamber 1, an outlet 4 for pulling out the silicon ingot 3 is formed just below the after heater 9, and the outlet 4 is sealed. have. The silicon ingot 3 is lowered while being supported by the support 14 descending through the outlet 4.

Immediately above the cooling crucible 7, the plasma torch 13 is formed to be liftable. The plasma torch 13 is connected to one pole of a plasma power supply device (not shown), and the other pole is connected to the silicon ingot 3 side. The plasma torch 13 is inserted into the upper portion of the cooling crucible 7 by lowering.

In the electroforming method using such an electronic casting device, the silicon raw material 11 is charged into the cooling crucible 7, an alternating current is applied to the induction coil 8, and the plasma is inserted into the upper part of the cooling crucible 7. The torch 13 is energized. At this time, since each piece of single-shaped pieces constituting the cooling crucible 7 is electrically divided with each other, an eddy current is generated in each piece with electromagnetic induction by the induction coil 8, An eddy current at the inner wall side of the cooling crucible 7 generates a magnetic field in the cooling crucible 7. Thereby, the silicon raw material 11 in the cooling crucible 7 is melted by electromagnetic induction heating, and the molten silicon 12 is formed. In addition, a plasma arc is generated between the plasma torch 13 and the molten silicon 12, and the silicon raw material 11 is also heated and melted by plasma heating, thereby reducing the burden of electromagnetic induction heating and efficiently melting silicon. (12) is formed.

The molten silicon 12 has an inner normal line on the surface of the molten silicon 12 due to the interaction between the magnetic field generated by the eddy current of the inner wall of the cooling crucible 7 and the current generated on the surface of the molten silicon 12. Since a force (pinch force) is applied in the direction, it is maintained in non-contact state with the cooling crucible 7. If the support 14 supporting the molten silicon 12 is gradually lowered while melting the silicon raw material 11 in the cooling crucible 7, the induction magnetic field decreases as it moves away from the lower end of the induction coil 8. In the heat generation amount and the pinch force, the solidification of the molten silicon 12 proceeds from the outer peripheral part by cooling from the cooling crucible 7. The silicon raw material 11 is solidified in one direction by continuously charging the silicon raw material 11 into the cooling crucible 7 with the lowering of the support 14 and continuing melting and solidification. ) Can be cast continuously.

During casting, in order to maintain the inside of the chamber 1 in an inert gas atmosphere, an inert gas is sequentially supplied from the inert gas inlet 5 at the top of the chamber 1, and the inert gas in the chamber 1 is supplied with the chamber ( It is discharged sequentially from the exhaust port 6 of the lower side wall of 1). At this time, SiO (silicon oxide) evaporates violently from the molten silicon 12 by the plasma arc from the plasma torch 13, and this SiO gas is finally discharged from the exhaust port 6 together with the inert gas.

According to such an electronic casting apparatus, contact between the molten silicon 12 and the cooling crucible 7 is reduced, so that impurity contamination from the cooling crucible 7 accompanying the contact is reduced, so that a high quality silicon ingot 3 is formed. You can get it. Moreover, since it is continuous casting, it becomes possible to manufacture the silicon ingot 3 at low cost.

International Publication WO 02/053496 Brochure

In the above-described electronic casting apparatus, the ambient temperature in the chamber 1 is higher at the center of the silicon ingot 3 and lowers as it gets closer to the side wall of the chamber 1, and the molten silicon 12 exists even at the same center. The higher it is, the higher. Due to this temperature difference, as shown by the solid line arrow in FIG. 4, natural convection of the atmospheric gas occurs in the chamber 1. Specifically, the atmosphere gas raises the gap between the inner circumferential surface of the after-heater 9 (crack heater 9b and thermal insulation heater 9a) and the outer circumferential surface of silicon ingot 3, and then moves up and down each time. Between adjacent crack heaters 9b, between the upper end of uppermost crack heater 9b, and the lower end of thermal insulation heater 9a, the upper end of thermal insulation heater 9a, and a cooling crucible After exiting to the outside of each heater 9a, 9b from between the lower end of (7), it becomes a convection which descends the vicinity of the side wall of the chamber 1.

As described above, part of the atmospheric gas that convections and rises between the inner circumferential surface of the after-heater 9 and the outer circumferential surface of the silicon ingot 3 is a cooling crucible that is kept in non-contact with each other, as indicated by the dotted arrows in FIG. 4. It also flows in between the inner peripheral surface of (7) and the outer peripheral surface of the silicon ingot (3). Then, when the metal impurity is contained in the convection atmosphere gas, the impurity enters between the inner circumferential surface of the cooling crucible 7 and the outer circumferential surface of the silicon ingot 3 and enters into the molten silicon 12. have. In this case, since the molten silicon 12 is contaminated with metallic impurities, the quality of the silicon ingot 3 cast from the molten silicon 12 is degraded.

Usually, the after-heater 9 is a resistance heating type heater, and the heat retention heater 9a employ | adopts carbon as a heat generating body which surrounds the silicon ingot 3 here. On the other hand, the crack heater 9b employs a metal wire of a heat-resistant alloy such as a cantal wire as a heating element surrounding the silicon ingot 3, and the metal wire is provided on the inner circumferential surface of the cylindrical heat insulating material held in the metal frame. It is composed. For this reason, in the process of raising an clearance gap between the inner peripheral surface of the after-heater 9 and the outer peripheral surface of the silicon ingot 3, metal impurities, such as Fe, Ni, Cr, etc. are discharged from the metal crack heater 9b. It is easy to be blown in.

This invention is made | formed in view of said problem, When molten silicon raises the gap between the inner peripheral surface of an after heater and the outer peripheral surface of an ingot at the time of continuous casting of a silicon ingot by an electronic casting method, molten silicon is a metal impurity It is an object of the present invention to provide an electronic casting device of a silicon ingot capable of suppressing contamination with.

MEANS TO SOLVE THE PROBLEM In order to achieve the said objective, this inventor repeated earnestly, paying attention to the flow of the atmospheric gas which naturally convections in a chamber at the time of casting, and performed various tests. As a result, the atmospheric gas rising between the inner circumferential surface of the after-heater and the outer circumferential surface of the ingot stops reaching the lower end of the cooling crucible, thereby resulting from the atmospheric gas flowing between the inner circumferential surface of the cooling crucible and the outer circumferential surface of the ingot. Recognizing that impurity contamination of molten silicon can be suppressed, the present invention has been completed.

The gist of the present invention resides in an electron casting device of a silicon ingot shown below. That is, a silicon raw material is charged into a conductive bottomless crucible disposed in a chamber, and the silicon raw material is melted by electromagnetic induction heating from an induction coil surrounding the bottomless cooling crucible, and the molten silicon is melted. In an electronic casting apparatus for solidifying a silicon ingot by solidifying while lowering from a cooling crucible without a bottom, a carbon insulated heater and a metal crack heater are disposed in this order under the bottom of the cooling crucible without a bottom. An electron in a silicon ingot comprising a heat-resistant nonwoven fabric contacting the outer circumferential surface of the silicon ingot over the entire circumference between the insulating heater and the crack heater over the entire circumference, and separating the gap between the inner circumferential surface of each heater and the outer circumferential surface of the silicon ingot up and down. Casting device.

In the above electronic casting device, the heat resistant nonwoven fabric is preferably composed of alumina fibers, SiO 2 fibers, or a mixed fiber thereof.

According to the electronic casting apparatus of the silicon ingot of this invention, even if a metal impurity is blown in from the metal crack heater in convection atmosphere gas, the atmosphere gas is gap between the inner peripheral surface of a heat insulation heater, and the outer peripheral surface of an ingot by a heat resistant nonwoven fabric. Since it is inhibited to rise to reach the lower end of the cooling crucible, the metal impurities do not enter the gap between the inner circumferential surface of the cooling crucible and the outer circumferential surface of the ingot and are not mixed in the molten silicon to suppress metal impurity contamination of the molten silicon. have.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically the structure of the electronic casting apparatus of this invention.
It is a figure which shows typically the structure of the electronic casting apparatus used for the comparison in the test of an Example.
FIG. 3 is a view showing measurement results of metal impurity concentration and life time in a silicon ingot by the test of the example, in which FIG. (A) shows Fe concentration, and (b) shows Ni concentration. (C) shows Cr concentration and (d) shows life time, respectively.
It is a figure which shows typically the structure of the conventional typical electronic casting apparatus used by the electronic casting method.

(Form to carry out invention)

EMBODIMENT OF THE INVENTION Below, embodiment is described in detail about the electronic casting apparatus of the silicon ingot of this invention.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically the structure of the electronic casting apparatus of this invention. The electroforming apparatus of this invention shown in the same figure is based on the structure of the electroforming apparatus shown in said FIG. 4, The same code | symbol is attached | subjected to the same structure as that, and the overlapping description is abbreviate | omitted suitably.

As shown in FIG. 1, in the electronic casting apparatus of this invention, between the thermal insulation heater 9a and the crack heater 9b, the clearance gap between the inner peripheral surface of each heater 9a, 9b, and the outer peripheral surface of the silicon ingot 3 is shown. The heat resistant nonwoven fabric 20 which divides into upper and lower sides is attached. The heat-resistant nonwoven fabric 20 elastically contacts the outer circumferential surface of the silicon ingot 3 over its entire circumference, and the atmosphere gas which raised the gap between the inner circumferential surface of the metal crack heater 9b and the outer circumferential surface of the silicon ingot 3 Further, the gap between the inner circumferential surface of the thermal insulation heater 9a and the outer circumferential surface of the silicon ingot 3 is raised to prevent reaching the lower end of the cooling crucible 7. At this time, since the heat resistant nonwoven fabric 20 is flexible, it does not damage or deform the silicon ingot 3 even if it contacts the silicon ingot 3.

As the heat resistant nonwoven fabric 20, alumina (Al 2 O 3 ) fibers, SiO 2 fibers, or mixed fibers thereof are very suitable. This is because these fibers have excellent heat resistance and do not cause metal contamination even when they are in contact with the silicon ingot 3. The thickness of the heat resistant nonwoven fabric 20 is preferably 10 mm or more in consideration of durability against continuous contact with the silicon ingot 3.

Moreover, the electroforming apparatus of this invention is equipped with the vent pipe 15 connected to the upper part and the lower part of the side wall of the chamber 1. Each end above and below this vent pipe 15 is opened in the position corresponding to the upper side of the cooling crucible 7, and the position corresponding to the lower side of the cooling crucible 7, respectively. In FIG. 1, although the vent pipe 15 was formed in the both sides which interpose the center axis of the chamber 1, respectively, the vent pipe 15 may be provided in one place and may be three or more places.

An inert gas inlet pipe 17 is connected to an inert gas inlet 5 for introducing an inert gas into the chamber 1, and an exhaust pipe 6 is provided in an exhaust port 6 for discharging the atmosphere gas in the chamber 1. 16) is connected. The amount of atmospheric gas discharged from the exhaust port 6 through the exhaust pipe 16 is adjusted by a flow control valve (not shown) provided in the exhaust pipe 16.

In the electroforming using the electroforming apparatus of such a structure, the part of the atmosphere gas which exists above the cooling crucible 7 in the chamber 1 as shown by the solid arrow in FIG. 1 is an opening here. It is introduced into the vent pipe 15 from the upper end of the vent pipe 15 to be lowered, and after lowering the inside of the vent pipe 15, it is discharged into the lower part of the chamber 1 corresponding to the lower side of the cooling crucible 7, and the vent pipe 15 is opened. The remainder which was not introduced into the wall is lowered near the side wall of the chamber 1.

The atmosphere gas introduced into the lower part of the chamber 1 through the vent pipe 15 and the atmosphere gas descending near the side wall of the chamber 1 are finally discharged from the exhaust port 6 to the outside of the chamber 1. Most convection naturally in the chamber 1. That is, the atmospheric gas existing in the lower part of the chamber 1 enters inside the crack heater 9b from below the lowest crack heater 9b, as shown by the solid arrow in FIG. The gap between the inner circumferential surface of the circumferential surface and the outer circumferential surface of the silicon ingot 3 is raised, and further rise is prevented by the heat resistant nonwoven fabric 20. For this reason, the atmospheric gas which raises the clearance gap between the inner peripheral surface of the crack heater 9b and the outer peripheral surface of the silicon ingot 3 is between the crack heaters 9b which adjoin up and down each time, and the topmost crack heater 9b. After exiting to the outside of each heater 9a, 9b from between the upper end of and the lower end of the heat retention heater 9a, the vicinity of the side wall of the chamber 1 is lowered again. Natural convection of such atmospheric gases occurs.

Therefore, according to the electroforming apparatus of the present invention, even when a metal impurity such as Fe, Ni, Cr, or the like is blown in from the metal crack heater 9b in the convection atmosphere gas, the atmosphere gas is prevented by the heat-resistant nonwoven fabric 20. Since the clearance between the inner circumferential surface of the thermal insulation heater 9a and the outer circumferential surface of the silicon ingot 3 is prevented from reaching the lower end of the cooling crucible 7, metal impurities are prevented from reaching the inner circumferential surface of the cooling crucible 7 and the silicon ingot ( The situation where it enters into the gap with the outer peripheral surface of 3) and mixes in the molten silicon 12 does not occur. As a result, metal impurity contamination of the molten silicon 12 can be suppressed, and the silicon ingot 3 excellent in quality can be manufactured.

(Example)

In order to confirm the effect by the electroforming apparatus of this invention, the silicon ingot of 346 mm x 504 mm rectangular cross section and 7000 mm in total length was continuously cast using the electroforming apparatus shown in the said FIG. At this time, the heat resistant nonwoven fabric of thickness 12.5mm comprised from the mixed fiber of alumina and SiO2 was used as this invention example 1, and two heat-resistant nonwoven fabrics comprised from the same mixed fiber and thickness were used as this invention example 2. In addition, the silicon ingot of the same dimension was continuously cast using the electron casting apparatus shown in following FIG. 2 for a comparison.

It is a figure which shows typically the structure of the electronic casting apparatus used for the comparison in the test of an Example. The electroforming apparatus used in the comparative example shown in the same drawing has an exhaust pipe 15 connected to the upper and lower portions of the sidewalls of the chamber 1 as compared to the electroforming apparatuses used in Examples 1 and 2 of the present invention shown in FIG. 1. Although common in this respect, they differ from each other in that they do not include a heat-resistant nonwoven fabric.

Any continuous casting was carried out by 5 batches, and the sample was sampled from each obtained ingot, and the test which measured the density | concentration and lifetime of a metal impurity was done. The sample was extract | collected from the center part of the ingot in the cross section corresponded to length 3600mm from the lower end of the ingot (the position of the head of continuous casting). The concentration of metal impurities was measured by component analysis by the total dissolution method, and the respective concentrations of Fe, Ni, and Cr were evaluated as metal impurities. The life time was evaluated by the microwave photoconductivity decay method (micro-PCD method).

FIG. 3 is a diagram showing measurement results of metal impurity concentration and life time in a silicon ingot by the test of the example, in which FIG. (A) shows Fe concentration, and (b) shows Ni concentration, (c) shows the Cr concentration, and (d) shows the life time, respectively. The density | concentration and the life time of each metal impurity shown in the same figure are the relative values which averaged the measured value of 5 batches in each of Example 1, 2, and the comparative example, and indexed the average value of the comparative example as 1 (reference).

From the results shown in Figs. 3A to 3D, in comparison with the comparative example using the electroforming apparatus provided with only the vent pipe, the concentrations of the metal impurities in the Examples 1 and 2 of the present invention were reduced by about 30% and the life was The time was improved by 1.4 to 1.7 times, and it became clear that metal impurity contamination of molten silicon could be suppressed.

According to the electroforming apparatus of the silicon ingot of the present invention, even when a metal impurity is blown from the metal crack heater in the convection atmosphere gas, the atmosphere gas is interposed between the inner circumferential surface of the thermal insulation heater and the outer circumferential surface of the ingot by the heat-resistant nonwoven fabric. It can be prevented from rising and reaching the lower end of a cooling crucible, and it becomes possible to suppress metal impurity contamination of molten silicon. Therefore, the electronic casting apparatus of this invention is very useful at the point which can manufacture the silicon ingot for solar cells which is excellent in quality.

1: chamber
2: raw material feeding hopper
3: silicon ingot
4: outlet
5: inert gas inlet
6: exhaust port
7: cooling crucible (without bottom)
8: induction coil
9: after heater
9a: heating heater
9b: crack heater
10: raw material introduction pipe
11: silicon raw material
12: molten silicon
13: plasma torch
14: support
15: vent pipe
16: exhaust pipe
17: inert gas introduction tube
20: heat resistant nonwoven fabric

Claims (2)

The silicon raw material is charged into a conductive bottomless cooling crucible disposed in the chamber, and the silicon raw material is melted by electromagnetic induction heating from an induction coil surrounding the bottomless cooling crucible, and the molten silicon is cooled without bottoms. In the electronic casting device which solidifies while lowering from the crucible to continuously cast a silicon ingot,
Below the cooling crucible without a bottom, a carbon thermal insulation heater and a metal crack heater are arranged in this order, surrounding a silicon ingot,
An electron in a silicon ingot comprising a heat-resistant nonwoven fabric contacting the outer circumferential surface of the silicon ingot over the entire circumference between the thermal insulation heater and the crack heater over the entire circumference and dividing the gap between the inner circumferential surface of each heater and the outer circumferential surface of the silicon ingot up and down. Casting device. The method of claim 1,
And the heat-resistant nonwoven fabric is composed of alumina fibers, SiO 2 fibers, or mixed fibers thereof.
KR1020100126879A 2010-08-31 2010-12-13 Apparatus for electromagnetic casting of silicon ingot KR20120021134A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JPJP-P-2010-193516 2010-08-31
JP2010193516A JP2012051739A (en) 2010-08-31 2010-08-31 Electromagnetic casting apparatus of silicon ingot

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Publication Number Publication Date
KR20120021134A true KR20120021134A (en) 2012-03-08

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