WO2008065829A1

WO2008065829A1 - Apparatus for production of trichlorosilane

Info

Publication number: WO2008065829A1
Application number: PCT/JP2007/070446
Authority: WO
Inventors: Toshiyuki Ishii
Original assignee: Mitsubishi Materials Corporation
Priority date: 2006-11-30
Filing date: 2007-10-19
Publication date: 2008-06-05
Also published as: JP2009096678A

Abstract

Disclosed is an apparatus for the production of trichlorosilane, which comprises a vessel for retaining a molten silicon therein, a heating mechanism for heating the molten silicon retained in the vessel, and a gas supply unit for blowing a supply gas comprising tetrachlorosilane and hydrogen into the molten silicon.

Description

Technical field

[0001] The present invention relates to conversion of tetrachlorosilane to trichlorosilane.

About.

This application (October 2006, November 30, 2006, Japanese Patent Application No. 2006—323693, filed September 26, 2007, Japanese Patent Application, 2007—249627, No.

Light

Insist on priorities and use the contents here.

Background art

book

[0002] Trichlorosilane used as a raw material for producing high-purity silicon (Si: silicon)

(SiHCl 3) is converted by reacting tetrachlorosilane (SiCl: silicon tetrachloride) with hydrogen.

3 4

And manufacturing.

That is, silicon is generated by the reduction reaction and thermal decomposition reaction of trichlorosilane according to the following reaction formulas (1) and (2). Trichlorosilane is produced by a conversion reaction according to the following reaction formula (3).

[0004] SiHCl + H → Si + 3HC1… hi)

3 2

4SiHCl → Si + 3SiCl + 2H (2)

3 4 2

SiCl + H → SiHCl + HC1 (3)

4 2 3

[0005] Various methods have been proposed as a method for producing this trichlorosilane. For example, in Patent Document 1, tetrachlorosilane and hydrogen are added to a heating element formed of graphite, silicon, or silicon carbide. A technique for spraying a feed gas containing it into trichlorosilane is disclosed. In this manufacturing technology, the sprayed supply gas comes into contact with the heating element, and is heated to obtain a reaction product gas containing trichlorosilane by a conversion reaction.

[0006] The following problems remain in the above conventional technique.

In the technique of Patent Document 1, a reaction product gas is obtained by blowing a supply gas onto a heating element formed of graphite, silicon or silicon carbide. But the inner wall of the heating element Since it is heating for a short time when it comes into contact with the substrate, there is a disadvantage that it is difficult to improve the conversion rate to trichlorosilane, which has a very high thermal efficiency. In addition, when a heating element formed of graphite is used, carbon, hydrogen, chlorosilane, and hydrogen chloride in the supply gas and reaction product gas react to produce methane, methylchlorosilane, silicon carbide, etc., and impurities. There was an inconvenience.

Patent Document 1: JP-A 53-97996

Disclosure of the invention

Problems to be solved by the invention

[0007] The present invention has been made in view of the above-described problems, and provides a trichlorosilane production apparatus capable of improving the conversion rate with high thermal efficiency and further preventing the generation of impurities. With the goal.

Means for solving the problem

The present invention employs the following configuration in order to solve the above-described problems. That is, the trichlorosilane manufacturing apparatus of the present invention blows a supply gas containing a container for storing molten silicon, a heating mechanism for heating the molten silicon in the container, and tetrachlorosilane and hydrogen into the molten silicon. A gas supply unit.

[0009] This trichlorosilane manufacturing apparatus includes a gas supply unit that blows out a supply gas containing tetrachlorosilane and hydrogen into molten silicon. For this reason, the supply gas is released in the form of bubbles in the heated high-temperature molten silicon, whereby it is efficiently heated and undergoes a conversion reaction, and trichlorosilane is obtained with a high conversion rate. Also, silicon is generated from the trichlorosilane in the generated reaction gas by a reduction reaction and a thermal decomposition reaction, and this silicon dissolves into the molten silicon, so that the molten silicon can be increased.

[0010] Further, in the trichlorosilane manufacturing apparatus of the present invention, the container is formed of quartz, and the gas supply unit includes a quartz nozzle that inserts a tip into the molten silicon and blows out the supply gas. May be. In this case, this trichlorosilane production apparatus uses quartz

The (SiO 2) nozzle is inserted into the molten silicon in the quartz container, and the supply gas is

2

Since the gas is blown out, impurities can be prevented from being mixed into the reaction product gas that does not generate impurities due to the container and the nozzle. [0011] As the quartz container, a crucible used for pulling and generating single crystal silicon can be suitably used.

[0012] The gas supply unit may be provided with a preheating mechanism for heating the supply gas before blowing it into the molten silicon. In this case, it is possible to reduce the thermal load of the molten silicon by blowing the gas into the molten silicon in a preheated state, and it is easy to maintain the silicon in a molten state, thereby reducing the size of the apparatus. It becomes possible to plan

[0013] A gas recovery mechanism for deriving a reaction product gas containing trichlorosilane and hydrogen chloride generated from the supply gas in the molten silicon to the outside from a gas outlet port disposed in an upper portion of the container is provided. It may be. In this case, since this trichlorosilane production apparatus is equipped with a gas recovery mechanism that leads to the outside from the gas outlet arranged in the upper part of the container, the reaction product gas released from the molten silicon is supplied to the gas outlet in the upper part of the container. Can be collected efficiently.

[0014] A support member may be provided to support the outer surface of the container so as to cover it. In this case, in this trichlorosilane manufacturing apparatus, the support member supports the outer surface of the container so that even if the quartz container is softened at a high temperature, the support member supports the container from the surroundings so that the container is supported from the surroundings. Shape change and the like can be prevented.

The invention's effect

[0015] According to the present invention, the following effects can be obtained.

The trichlorosilane production apparatus according to the present invention includes a gas supply unit that blows out a supply gas containing tetrachlorosilane and hydrogen into the molten silicon! /, So that the supply in a bubble state in the molten silicon is provided. Trichlorosilane can be obtained at a high conversion rate by being heated efficiently by contact between the gas and molten silicon. In addition, the silicon produced by the reduction reaction and thermal decomposition reaction from a part of the trichlorosilane in the reaction gas is dissolved in the molten silicon, so that it is possible to increase the amount of molten silicon. Furthermore, it is possible to prevent the generation of impurities by configuring the container and the nozzle of the gas supply unit using quartz without using a carbon material. Accordingly, trichlorosilane having high conversion and high purity can be obtained, and silicon can be produced at the same time. Brief Description of Drawings

FIG. 1 is a simplified cross-sectional view showing an embodiment of a trichlorosilane production apparatus according to the present invention.

Explanation of symbols

[0017] 1 · · · Container, 2 · · · Heating mechanism, 3 · · Gas supply section, 4 · · Gas outlet, 5 · · Gas recovery mechanism, 6 · · · Quartz nozzle, 6a ... Air outlet, 7 ... carbon support member, 8 ... outer cylinder member, 11 ... preheating mechanism, S ... molten silicon.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of a trichlorosilane production apparatus according to the present invention will be described with reference to FIG.

As shown in FIG. 1, the trichlorosilane production apparatus of the present embodiment includes a quartz (SiO 2) container 1 that stores molten silicon S, and a heating mechanism 2 that heats molten silicon S in the container 1. , Te

2

A gas supply unit 3 for blowing a supply gas containing trachlorosilane and hydrogen into the molten silicon S, and a reaction product gas containing trichlorosilane and hydrogen chloride generated from the supply gas in the molten silicon S And a gas recovery mechanism 5 that leads to the outside from a gas outlet 4 arranged in

[0020] In the illustrated example, the container 1 uses a quartz crucible used for pulling and generating single crystal silicon, and the inner bottom surface is formed into an arcuate concave surface la and the arcuate concave surface la is used. A continuous cylindrical inner surface lb is formed at the top.

[0021] The gas supply unit 3 includes a quartz nozzle 6 whose tip is inserted into the molten silicon S and blows out the supply gas, and a pressure pump P1 connected to the quartz nozzle 6 to supply the supply gas under pressure P1 And a supply source (not shown) of a supply gas connected to the pressure pump P1, and a preheating mechanism 11 for heating the supply gas before blowing it into the molten silicon S.

The quartz nozzle 6 is inserted vertically upward from the top of the container 1, and a plurality of outlets 6 b are formed in the end plate 6 a that closes the tip of the quartz nozzle 6. The supply gas is blown into the molten silicon S from the port 6b. The supply gas blown out is dispersed as bubbles in the molten silicon S.

[0023] On the outside of the quartz nozzle 6, there is an outer cylinder member 8 arranged coaxially with the quartz nozzle 6. It is fixed to the top of the container 1. A space between the quartz nozzle 6 and the outer cylinder member 8 serves as a reaction product gas outlet channel, and the lower end opening serves as the gas outlet port 4. That is, the quartz nozzle 6 and the outer cylinder member 8 have a double tube structure. In this case, the outer cylinder member 8 is fixed to the upper end portion of the container 1 via the ring-shaped closing member 12.

[0024] Further, the gas recovery mechanism 5 is provided with an exhaust pump P2 connected to the gas outlet 4 and sucking the reaction product gas! /, When the reaction product gas can be discharged by a pressure difference The exhaust pump can be omitted.

[0025] The quartz container 1 is supported by a carbon support member 7 so as to cover the outer surface thereof.

[0026] The carbon support member 7 includes a support portion body 7a having an inner surface that houses the container 1 and contacts the entire outer surface thereof, and a support column portion 7b provided at a lower portion of the support portion body 7a. It is equipped with.

[0027] The heating mechanism 2 includes a heater part 2a that is a heat generating part disposed around the container 1 so as to surround the container 1, and an electrode that is connected to a lower part of the heater part 2a and allows a current to flow through the heater part 2a. The portion 2b and an annular bottom heater portion 9 disposed below the container 1 are provided. The electrode portion 2b is connected to a power source (not shown). The bottom heater portion 9 is installed below the support portion main body 7a in a state where the support column portion 7b of the carbon support member 7 is passed through. In addition, the bottom heater unit 9 is also not shown in FIG.

[0028] In addition, the heating mechanism 2 performs heating control so that the molten silicon S in the container 1 has a melting temperature of 1420 ° C. Since the feed gas is heated to 1200 ° C or higher, the conversion rate is improved. Further, disilanes may be introduced into the supply gas and the silanes may be taken out.

[0029] In this trichlorosilane production apparatus, when a supply gas is blown into the molten silicon S from the quartz nozzle 6, the molten silicon S in a high temperature state and the supply gas in a bubble state come into contact with each other to react to react and generate a reaction product gas. Is generated. At this time, silicon is further generated from a part of trichlorosilane contained in the reaction product gas by a reduction reaction and a thermal decomposition reaction, and this silicon is dissolved in the molten silicon. The remaining reaction product gas is discharged upward from the molten silicon S, and is led out through the gas outlet 4 at the top of the container 1 to be recovered.

[0030] Thus, in the present embodiment, a supply gas containing tetrachlorosilane and hydrogen is melted with silicon. Since the gas supply unit 3 that blows out into the gas S is provided, the supply gas is released in the form of bubbles into the heated high-temperature molten silicon S. Trichlorosilane is obtained at a high rate. In addition, silicon is generated from the trichlorosilane in the generated reaction gas by a reduction reaction and a thermal decomposition reaction, and this silicon dissolves into the molten silicon S. Therefore, the molten silicon S can be increased.

[0031] Further, since the tip of the quartz nozzle 6 is inserted into the molten silicon S in the quartz container 1 and the supply gas is blown out, there is no generation of impurities due to the container 1 and the quartz nozzle 6. It is possible to prevent impurities from being mixed into the reaction product gas.

[0032] In addition, since the gas recovery mechanism 5 that leads to the outside from the gas outlet 4 disposed in the upper part of the container 1 is provided, the reaction product gas released from the molten silicon S is supplied to the gas outlet in the upper part of the container 1. It can be efficiently recovered from 4.

[0033] Since the periphery of the container 1 is supported by the carbon support member 7, even if the quartz container 1 is softened at a high temperature, the container 1 is supported by the carbon support member 7 from the periphery. It is possible to prevent changes in the shape and the like.

Note that the technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0035] For example, in the above embodiment, as the heating mechanism 2, the molten silicon S is heated by other methods such as a force S for heating the molten silicon S in the container 1 by radiant heat from the heater 2a, high-frequency induction heating, and the like. It doesn't matter.

In the above embodiment, a force S using one quartz nozzle 6 and a plurality of quartz nozzles 6 may be employed. In this case, in the above embodiment, the outlet is formed in the end plate. However, the supply gas may be directly blown out from the nozzle opening by reducing the diameter of each nozzle.

Industrial applicability

[0037] According to the trichlorosilane production apparatus of the present invention, trichlorosilane can be obtained with a high conversion rate. In addition, since silicon generated by a reduction reaction and thermal decomposition reaction from a part of trichlorosilane in the generated reaction gas dissolves in the molten silicon, it is possible to increase the molten silicon. For this reason, it is used as a raw material for producing high-purity silicon. _C which can be suitably used in the production process of trichlorosilane

Claims

The scope of the claims

[1] a container for storing molten silicon;

A heating mechanism for heating the molten silicon in the container;

An apparatus for producing trichlorosilane, comprising: a gas supply unit that blows out a supply gas containing tetrachlorosilane and hydrogen into the molten silicon.

[2] The container is formed of quartz,

2. The apparatus for producing trichlorosilane according to claim 1, wherein the gas supply unit includes a quartz nozzle having a tip inserted into the molten silicon and blowing out the supply gas.

3. The apparatus for producing trichlorosilane according to claim 1, wherein the gas supply unit is provided with a preheating mechanism that heats the supply gas before blowing it into the molten silicon.

[4] A gas recovery mechanism for deriving a reaction product gas containing trichlorosilane and hydrogen chloride generated from the supply gas in the molten silicon to the outside from a gas outlet port disposed at an upper portion of the container. The apparatus for producing trichlorosilane according to claim 1.

5. The trichlorosilane production apparatus according to claim 1, further comprising a support member that supports the outer surface of the container so as to cover the outer surface.