JPH01278411A - Production of hexachlorodisilane and octachlorotrisilane - Google Patents

Abstract

PURPOSE:To obtain Si2Cl6 and Si3Cl8 useful as a raw material for the production of semiconductor, etc., in high yield and efficiency, at a low cost by reacting a specific higher chloropolysilane with chlorine gas in the presence of copper (compound). CONSTITUTION:Higher chloropolysilanes expressed by SinCl2n+2 (n>=4) are recovered as by-products in the production of Si2Cl6 and Si3Cl8 by the chlorination of silicon granules, etc. The recovered higher chloropolysilane is made to react with chlorine gas in the presence of copper and/or a copper compound (e.g. cuprous chloride or cupric oxide) to obtain hexachlorodisilane (Si2Cl6) and octachlorotrisilane (Si3Cl8). The amount of the copper (compound) to be added to the higher chloropolysilane is preferably 0.01-0.5wt.% in terms of copper and the reaction temperature of the higher chloropolysilane with chlorine is preferably 100-200 deg.C.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention uses a higher chloropolysilane represented by the general formula 5inC1□, 2 (n≧4) as a raw material to produce hexachlorodisilane Si3Cl6 and octachlorotrisilane Si
The present invention relates to a method for producing 3Cl6.

Chloropolysilane has recently gained importance as a raw material for the production of semiconductor silicon.

Of course, chloropolysilane can be thermally decomposed as it is to produce epitaxial silicon, etc.8, but it is also used as a silica source for optical communications with a high germanium doping rate. In addition, chloropolysilane is further reduced to 5inH, n+1
The silane represented by (n≧2) is thermally decomposed and becomes a raw material for manufacturing silicon for semiconductors and amorphous silicon. For example, when disilane, Si, H, is used to form an amorphous silicon film by thermal decomposition or glow discharge decomposition, the deposition rate of the film formed on the substrate is much higher than that of monosilane, SiH, and This film has advantages such as excellent electrical properties, and demand is expected to increase significantly in the future as a raw material for semiconductors for solar cells.

(Prior Art and Problems) Conventionally, chlorpolysilane has been produced by heating silicide particles such as calcium silicon, magnesium silicon, or ferrosilicon, or metal silicon particles and supplying chlorine gas to chlorinate them. ing.

However, when producing chloropolysilane by the method of chlorinating silicide particles, there is a problem that solid by-products such as calcium chloride and magnesium chloride are produced.
A commercial production method that does not generate solid by-products is desired.

Furthermore, although no solid by-products are observed in the reaction between silicon particles and chlorine, the production rate of bechlorpolysilane is 1% based on silicon atoms in the method using the silicide alloy described above.
There is a significantly lower interpressure.

Incidentally, the chlorosilane produced in the conventional method is mainly 5
iC1, and chloropolysilane 5i2CISi,
CI simply uses what is by-produced with the generation of 5iC1.

In addition, in a method for the purpose of producing hexachlorodisilane (Si2C1g) (Japanese Patent Application Laid-open No. 1959-119),
Higher chloropolysilane (SiylClz net, n≧4) produced as a by-product during the production of 5i2C1° and Si, CI
React with chlorine again.

This is decomposed to improve the yield of Si3Cl6.

In this method, the reaction is carried out at a high temperature (300-500°C), but since 5iC14 is stable at this temperature, Si, C
The yield of 1Si, C1, is low, and to compensate for this, 5i
It is believed that the reason why such measures are required is that the concentration of 5iC1 between the reaction systems must be increased by separating and circulating C14, and the reaction temperature is high.

(Knowledge regarding problem solving) The present inventors have pursued an efficient method for producing Si, C1, and Si, C1, which overcomes the problems described above. It has been found that when reacting with chlorine, the reaction proceeds at a low temperature and the yield of the target compound is also good.

(Structure of the Invention) The present invention provides hexachlorodisilane, Si , C1° and octachlorotrisilane, Si, C1°.

The copper compound used in the method of the present invention is a compound containing copper, which produces 5i2C1 and Si,
Although there are no particular limitations as long as they do not contaminate C1, cuprous chloride CuC1, cupric chloride CuC1□ are preferably used because they are used as catalysts in chlorination reactions, and cuprous chloride @Cu, O1 cupric oxide CuO may also be used.

The amount of the copper or copper compound added is preferably 0.01 to 0.5% by weight relative to the higher chloropolysilane in terms of copper.
If the amount added is less than 0.01% by weight, the progress of the reaction will be extremely slow and no significant effect will be shown;
．． Even if it exceeds 5% by weight, the amount added will be 0.0% in terms of catalytic effect.
There is no difference at 5% by weight or less.

In the method of the present invention, the reaction temperature between the higher chloropolysilane and the chlorine gas is preferably 100 to 200''C.The reaction temperature and the effect of the copper catalyst are estimated as follows.

Decachlortetrasilane 5, a high-grade chloropolysilane
i4C1□. The reaction process is expressed by the following reaction formula.

■ 3Si4C1 construction. +C12+ 4Si, C1s
(A) (z) ■ 5L4C1□. +C1□ □2Sx2C1, (B) (cup) ■ 5i4C1□. + 3 C1z, 4 SiCl-
(C) (Φ) In the method of the present invention, the above-mentioned (A), (B) and (C) occur in parallel at a low temperature of 100 to 200°C.

When chlorine gas is blown into 5L4C11° in the presence of a copper-based catalyst, the reaction (■) in (A) takes precedence, and Si, C1,
can be produced more than Si3Cl6 or 5iC14. When a certain amount of Si and C1° is produced, the reaction (■), which is the reverse reaction of (■), occurs, and the rate of formation of 5i3CI slows down, and (B)
The reaction (2) gradually begins to take priority and Si3Cl6 is formed. When Si, C1° accumulates to a certain extent, the reaction (■), which is the reverse reaction of (2), cannot be ignored, and the production rate of Si, C1, slows down, and the reaction (C) (■) gradually increases.5
Generated by iC14. Since 5iC1 is a stable substance, the reaction with [Yes] is difficult to proceed. In the reaction system, 5iC14 is more stable at higher temperatures than at lower temperatures. Therefore, under conditions of 300 to 500°C, the reaction (■) takes precedence over the reactions (2) and (2), and 5iC14 is mainly produced, resulting in Si, C1,
And the yield of Si and C1° decreases.

The copper-based catalyst promotes the chlorination reaction at a low temperature of 100 to 200°C, and the first reaction (1) progresses, followed by the second reaction (2), which improves the yield of SL, C1, and 5L2C1.

In this case, chlorine gas is blown into the target Si, C1
The process is stopped when the amounts of °, SL, and C1° become maximum. When more chlorine gas is blown into the reactor, the reaction (2) gradually takes priority and a large amount of 5iC1 is produced, resulting in a decrease in the yield of Si, C1, and Si, CI.

Note that the chlorine gas used in the present invention may be a commercially available one, but it is desirable to dry it thoroughly before use.

(Effects of the Invention) According to the present invention, silicon grains etc. are chlorinated to form Si3Cl
Both objective compounds can be efficiently produced from the higher chloropolysilane produced as a by-product in the method for producing 6, Si, and CI. Furthermore, since the method of the present invention performs the reaction at a low temperature, there is no need to add 5iC14 to the reaction system, and it is advantageous in terms of operation and energy cost, and it can produce s1□C1 and Si in a high yield. C1, can be manufactured.

(Example) Next, the present invention will be explained in more detail with reference to Examples.
The following examples are not intended to limit the scope of the invention.

Example 1 Using a 30 flask equipped with a chlorine gas supply port, a thermometer mounting port, and a condenser mounting port, high-grade chloropolysilane 6 was used.
96g (The weight% of the content is 5inC1□□0 (n≧4
)78.5%, Si3Cl615,8,5i2CI,
3. ．． Add 0.4% by weight of cuprous chloride to 6.51C142,1), mix well and place in the above flask.
As a result of blowing chlorine gas at a flow rate of 250 cc/min for 90 minutes at ℃, 753 g of product liquid was obtained. The product liquid is a mixture of the residual liquid in the flask and the liquid condensed in the cold trap. The composition of the produced liquid is 5iC144
,0,SL3Cl650,1,Si3Cl632,2,
5irlcx2r+z (n≧4) 13.7 (weight%)
Met.

Examples 2 to 8 Table 1 shows the results of reactions conducted in the same manner as in Example 1 while changing the temperature, type of catalyst, and addition rate.

Comparative Example Same as Example 1 except that the reaction temperature was 300°C and 70°C.
Table 2 shows the results of the reaction conducted in the same manner as (Comparative Examples 1 to
3).

Table 2 shows the results of reactions carried out at 150°C and 300°C without adding a catalyst (Comparative Examples 4 to 5).

As is clear from Table 2, compared to the Examples, the yield of Si3Cl6, which is less than Si and C1, is lower than that of Daifuku in the Comparative Examples.

Claims (1)

[Claims] 1. Hexachlorodisilane, Si_2Cl_6 and A method for producing octachlorotrisilane, Si_3Cl_6. 2. The amount of copper, a copper compound, or a mixture thereof added to the higher chloropolysilane is 0.01 to 0.0 in terms of copper.
5% by weight, and the reaction temperature of the higher chloropolysilane and chlorine is 100°C or more and 200°C or less.