JP2008150277A - Heat-resistant and corrosion-resistant member, and apparatus for producing trichlorosilane - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-resistant and corrosion-resistant member and an apparatus for producing trichlorosilane having higher corrosion resistance and a longer operating life even at an elevated temperature. <P>SOLUTION: At least the surface of the heat resistant and corrosion resistant member to be disposed in a circumstance where it comes into contact with a mixture gas containing tetrachlorosilane and hydrogen at an elevated temperature is formed by diamond or diamond-like carbon. Besides, the apparatus for producing trichlorosilane is provided with a reaction vessel 1 in which tetrachlorosilane and hydrogen is supplied and a reaction product gas containing trichlorosilane and hydrogen chloride is produced by conversion reaction at an elevated temperature, the reaction vessel 1 being constituted by using the above heat resistant corrosion resistant member. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat and corrosion resistant member suitable for a constituent member of a reaction vessel for converting tetrachlorosilane to trichlorosilane, and a trichlorosilane production apparatus using the same.

Trichlorosilane (SiHCl ₃ ) used as a raw material for producing high-purity silicon (Si: silicon) can be produced by converting tetrachlorosilane (SiCl ₄ : silicon tetrachloride) with hydrogen.

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

SiHCl ₃ + H ₂ → Si + 3HCl (1)
4SiHCl ₃ → Si + 3SiCl ₄ + 2H ₂ (2)
SiCl ₄ + H ₂ → SiHCl ₃ + HCl (3)
The above conversion reaction is performed by introducing a feed gas of tetrachlorosilane and hydrogen into a reaction vessel in a high temperature state. However, when carbon is used as a component of the reaction vessel, the supply gas in the high temperature state and reaction generation There is a problem that hydrogen, chlorosilane, hydrogen chloride (HCl), and the like in the gas react to generate methane, methylchlorosilane, silicon carbide, and the like and become impurities.

For this reason, for example, Patent Document 1 proposes an apparatus in which a carbon surface coated with SiC (silicon carbide) is used for members such as an inner cylinder, an outer cylinder, and a diverter constituting a reaction vessel.
JP 2004-262755 A

  The following problems remain in the conventional technology.

  That is, if a member having a SiC coating is used as a member constituting the reaction vessel, direct contact between the gas components in the supply gas and the reaction product gas and carbon is prevented, thereby preventing the generation of the impurities. However, the SiC coating film is gradually etched and deteriorated by the high-temperature supply gas and reaction product gas.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a heat and corrosion resistant member having higher corrosion resistance and a longer life even at high temperatures and a trichlorosilane production apparatus using the same.

  The present invention employs the following configuration in order to solve the above problems. That is, the heat and corrosion resistant member of the present invention is a heat and corrosion resistant member disposed in an environment where a mixed gas containing tetrachlorosilane and hydrogen contacts at high temperature, and at least the surface is formed of diamond or diamond-like carbon (DLC). It is characterized by being. That is, in this heat and corrosion resistant member, the surface is formed of diamond or diamond-like carbon having an etching speed that is about an order of magnitude slower than conventional SiC and high corrosion resistance.

  In addition, the heat and corrosion resistant member of the present invention is characterized in that a coating film of diamond or diamond-like carbon is formed on the surface of a carbon material. That is, in this heat and corrosion resistant member, since a carbon material is used as a base material, members having various shapes can be produced at a relatively low cost. In addition, since the diamond or diamond-like carbon coating film is composed of a carbon material applied to the surface, the high-corrosion-resistant diamond or diamond-like carbon coating film and a mixed gas of tetrachlorosilane and hydrogen in a high temperature state and its It is possible to prevent the reaction product gas from coming into direct contact with the carbon material for a longer period. Therefore, it can be prevented that carbon, hydrogen, chlorosilane, and hydrogen chloride in the mixed gas and the reaction product gas react to generate methane, methylchlorosilane, silicon carbide, and the like to become impurities.

  In addition, the heat and corrosion resistant member of the present invention is characterized in that a coating film of diamond or diamond-like carbon is formed on the surface of a silicon carbide material. That is, in this heat and corrosion resistant member, since the silicon carbide material is used as the base material, it is possible to achieve a longer life compared to the case where the carbon material is used as the base material. Moreover, compared with the case where a carbon material is used as a base material, strong adhesion can be obtained between the base material and the coating film, and a denser coating film can be formed.

  The heat and corrosion resistant member of the present invention is characterized in that a silicon carbide coating film is formed on the surface of a carbon material, and further a diamond or diamond-like carbon coating film is formed on the surface thereof. To do. That is, in this heat and corrosion resistant member, since a carbon material is used as a base material, members having various shapes can be produced at a relatively low cost. In addition, when a silicon carbide coating film is formed and a diamond or diamond-like carbon coating film is formed on the surface thereof, a diamond or diamond-like carbon coating film is formed on a carbon material as a base material. As compared with the above, it is possible to obtain strong adhesion between the substrate and the coating film, and it is possible to form a denser coating film.

  The trichlorosilane production apparatus of the present invention is a trichlorosilane production apparatus that generates a reaction product gas containing trichlorosilane and hydrogen chloride by converting a supply gas containing tetrachlorosilane and hydrogen at a high temperature. It is characterized by using the heat and corrosion resistant member of the invention. That is, in this trichlorosilane production apparatus, since it is configured using the heat and corrosion resistant member of the present invention, it is possible to extend the life of the reaction vessel, heat insulating material, sealing material, insulating material and the like which are the apparatus constituent members. In addition, the generation of impurities can be prevented over a long period of time.

  The trichlorosilane production apparatus of the present invention includes a reaction vessel in which a supply gas containing tetrachlorosilane and hydrogen is supplied to the inside and a reaction product gas containing trichlorosilane and hydrogen chloride is generated by a conversion reaction at a high temperature. And the reaction vessel is configured using the heat and corrosion resistant member. That is, in this trichlorosilane production apparatus, the reaction vessel in which the conversion reaction is performed inside and the heat and corrosion resistance is required among the device components is constituted by using the heat and corrosion resistant member. Deterioration can be suppressed and a stable conversion reaction can be obtained over a long period of time.

  Furthermore, in the trichlorosilane production apparatus of the present invention, the reaction vessel includes a diverter that changes a flow direction of the supply gas or the reaction product gas, and the diverter is formed of the heat-resistant and corrosion-resistant member. And That is, in this trichlorosilane manufacturing apparatus, since the diverter is formed of a heat-resistant and corrosion-resistant member, the flow direction of the diverter that is easily etched can be suppressed by changing the flow direction of the supply gas and the reaction product gas.

  The present invention has the following effects.

  That is, according to the heat-resistant and corrosion-resistant member according to the present invention, the surface is formed of diamond or diamond-like carbon having higher corrosion resistance than conventional SiC, so that a longer life can be achieved. Therefore, according to the trichlorosilane production apparatus using the heat-resistant and corrosion-resistant member of the present invention as a structural member such as a reaction vessel, it is possible to extend the life of the reaction vessel and the like, and prevent the generation of impurities over a long period of time. High trichlorosilane can be obtained.

  Hereinafter, one embodiment of a heat and corrosion resistant member and a trichlorosilane manufacturing apparatus according to the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the trichlorosilane production apparatus of this embodiment is a reaction vessel in which a supply gas of tetrachlorosilane and hydrogen is supplied to the inside and a reaction product gas of trichlorosilane and hydrogen chloride is generated by a conversion reaction. 1, a heating mechanism 2 arranged around the reaction vessel 1 for heating the reaction vessel 1, a gas supply pipe 3 for supplying a supply gas into the reaction vessel 1, and a reaction product gas from the reaction vessel 1 to the outside A plurality of gas outlet pipes 4, a heat insulating material 5 disposed so as to cover the periphery of the reaction vessel 1 and the heating mechanism 2, a storage container 6 for storing the reaction vessel 1, the heating mechanism 2 and the heat insulating material 5, and storage An argon supply mechanism 7 for supplying argon (Ar) into the container 6 is provided.

  As shown in FIGS. 1 and 2, the reaction vessel 1 includes cylindrical first to fourth reaction cylinder walls 9a to 9d having different inner diameters for partitioning the internal space into a plurality of small spaces 8a to 8d. I have. That is, the space in the reaction vessel 1 (the space inside the outermost fourth reaction cylinder wall 9d) is composed of one columnar small space 8a at the center by three first to third reaction inner walls 9a to 9c. The outside is partitioned into three small cylindrical spaces 8b to 8d. In addition, the gas supply pipe 3 communicates with a lower portion of a cylindrical small section 8a that is an inner space of the innermost first reaction cylinder wall 9a, and the gas outlet pipe 4 is connected to the outermost small space 8d. ing.

The first to fourth reaction cylinder walls 9 a to 9 d are supported by being inserted into the ring-shaped groove 21 on the upper surface of the lower support disc 11 at the lower portion and the ring shape on the lower surface of the upper support disc 12. The groove 22 is inserted and supported. The upper part of the upper support disk 12 is fixed to the heat insulating material 5 at the upper part of the reaction vessel 1.

  In addition, the first to third reaction cylinder walls 9a to 9c are formed with cutout portions 10 alternately in the upper part and the lower part in order from the inside. That is, the first reaction tube wall 9a is formed with a plurality of notches 10 in the upper portion at intervals in the circumferential direction, and the second reaction tube wall 9b is formed with a plurality of notches 10 in the lower portion at intervals in the circumferential direction. Is formed. A plurality of notches 10 are formed in the upper part of the third reaction cylinder wall 9c. These notches 10 are formed sufficiently larger than the depth of the ring-shaped grooves 21 and 22 of the upper and lower support disks 11 and 12 into which the reaction cylinder walls 9a to 9c are fitted. As shown in FIG. 1, the notch 10 is exposed from the ring-shaped grooves 21 and 22 with the reaction cylinder walls 9a to 9c fitted in the ring-shaped grooves 21 and 22 and penetrates the front and back of the reaction cylinder walls 9a to 9c. It is supposed to be a flow path. And the reaction flow path 20 which made each small space 8a-8d a communication state sequentially from the inner side by these notch parts 10 is comprised.

  A central hole 11b is formed in the lower support disc 11, and the small space 8a inside the first reaction cylinder wall 9a and the gas supply pipe 3 are communicated with each other through the central hole 11b.

  The gas supply pipe 3 and the gas outlet pipe 4 are connected to a supply hole 6a and an exhaust hole 6b formed at the lower part of the storage container 6 with their upper ends fixed to the lower part of the storage container 6, respectively. In the lower part of the reaction vessel 1, a supply connecting pipe 13 is provided in the center through the heat insulating material 5, and two concentric with the supply connecting pipe 13 as shown in FIGS. 1 and 3. Cylindrical bodies 14A and 14B are provided through the heat insulating material 5, and an exhaust connecting flow path 23 is formed in a cylindrical shape between the cylindrical bodies 14A and 14B. The upper end openings of the supply hole 6a and the exhaust hole 6b communicate with the lower end openings of the supply connection pipe 13 and the exhaust connection flow path 23, respectively. The upper ends of the cylinders 14 </ b> A and 14 </ b> B constituting the exhaust connection flow path 23 are fixed to the lower part of the lower support disc 11, and the exhaust connection flow path 23 passes through the outer through hole 11 a of the lower support disc 11. To the outermost small space 8d (inside the outermost fourth reaction cylinder wall 9d). In addition, the upper end opening of the connecting pipe for supply 13 is fixed to the lower center of the lower support disc 11, and a small space 8 a inside the first reaction cylinder wall 9 a through the central through hole 11 b of the lower support disc 11. It is connected to the.

  Accordingly, the supply gas supplied from the gas supply pipe 3 to the small space 8a on the inner side of the first reaction cylinder wall 9a reacts while sequentially flowing to the outer small spaces 8b to 8d through the plurality of notches 10 while being heated. The reaction product gas is set. In this case, the gas passes through the notch 10 in the radial direction while alternately colliding with the upper support disk 12 and the lower support disk 11 in each of the small spaces 8a to 8d, thereby causing the small spaces 8a to 8d. The flow direction is set so that the flow direction changes repeatedly in the upward and downward directions for each of the small spaces 8a to 8d. That is, the upper support disc 12 and the lower support disc 11 are tie barters that change the gas flow direction. In the figure, the direction of gas flow is indicated by arrows.

  As shown in FIG. 3, eight gas outlet pipes 4 are arranged at equal intervals in the circumferential direction of the exhaust connecting flow path 23.

  A supply source (not shown) of supply gas is connected to the gas supply pipe 3. In the gas outlet pipe 4, the reaction product gas is discharged to the outside due to the pressure difference in the pipe, but an exhaust pump may be connected.

  Each component of the reaction vessel 1, in the case of this embodiment, the first to fourth reaction cylinder walls 9 a to 9 d and the lower support disk 11 and the upper support disk 12 as a diverter are diamond or diamond on the surface of the carbon material. It is a heat-resistant and corrosion-resistant member formed by forming a like carbon coating film. Diamond-like carbon is a hard film mainly made of amorphous carbon or an allotrope of carbon. The diamond or diamond-like carbon coating film is formed by, for example, a CVD method or a PVD method.

  The storage container 6 includes a cylindrical wall 31, a bottom plate portion 32 and a top plate portion 33 that close both ends thereof, and is made of stainless steel.

  The heating mechanism 2 includes a heater unit 15 that is a heating element disposed around the reaction vessel 1 so as to surround the reaction vessel 1, and an electrode that is connected to the lower portion of the heater unit 15 and allows a current to flow through the heater unit 15. Part 16. The electrode unit 16 is connected to a power source (not shown). The heater portion 15 is made of carbon, but may be made of the heat and corrosion resistant member. Moreover, the heating mechanism 2 performs heating control so that the temperature in the reaction vessel 1 is in the range of 800 ° C. to 1400 ° C. In addition, if the inside of reaction container 1 is set to 1200 degreeC or more, a conversion rate will improve. Further, disilanes may be introduced and the silanes may be taken out.

  The heat insulating material 5 is formed of carbon, for example, and is attached to the inner wall surface of the cylindrical wall 31, the upper surface of the bottom plate portion 32, and the lower surface of the top plate portion 33 so as to be attached to the storage container 6. . You may comprise this heat insulating material 5 also with the said heat-resistant corrosion-resistant member.

  Further, the lower support disk 11 of the reaction vessel 1 is installed in a state of being floated from a heat insulating material (heat insulating material on the bottom plate portion 32 of the storage container 6) 5 disposed below the heat insulating material. It is a space.

A temperature sensor S that protrudes into the outermost small space 8 of the reaction channel 20 is fixed to the lower surface of the upper support disc 12. The temperature is controlled by the heating mechanism 2 while measuring the temperature by the temperature sensor S.

  The argon supply mechanism 7 includes an argon supply pipe 17 penetrating through the lower part of the storage container 6 and the heat insulating material 5 and having a tip protruding into the storage container 6, and an argon supply source 18 connected to the argon supply pipe 17. ing. The argon supply mechanism 7 controls the supply of argon so that the inside of the storage container 6 is in a predetermined pressurized state. A container pump (not shown) for replacing the internal atmosphere and evacuating argon is connected to the upper part of the storage container 6.

  Thus, in this embodiment, since the through-holes 10 for circulation are alternately formed in the upper part and the lower part in order from the inside in the first to third reaction cylinder walls 9a to 9c, the gas flows in the reaction flow path 20. The direction of flow changes alternately from the top to the bottom and from the bottom to the top each time it moves outward. Therefore, the long reaction flow path 20 is secured in the reaction vessel 1 and the heat transfer area is increased by the plurality of first to fourth reaction cylinder walls 9a to 9d, so that the supply gas reacts. Sufficient holding time and heating can be ensured, and the conversion rate can be further improved.

  In this embodiment, each of the reaction cylinder walls 9a to 9d and the lower support disk 11 and the upper support disk 12 as a diverter are made of a carbon material having a diamond or diamond-like carbon coating film applied to the surface. Therefore, the mixed gas of tetrachlorosilane and hydrogen at high temperature and its reaction product gas are directly applied to the carbon material by the coating film of diamond or diamond-like carbon whose etching speed is about an order of magnitude slower than conventional SiC and has high corrosion resistance. Contact can be prevented for a longer period. Thereby, deterioration of the wall surface of the reaction channel 20 is suppressed, and hydrogen, chlorosilane, and hydrogen chloride in the mixed gas and the reaction product gas react to generate methane, methylchlorosilane, silicon carbide, and the like as impurities. Can be prevented. Moreover, since the carbon material is used as the base material, the reaction cylinder walls 9a to 9d and the both supporting disks 11 and 12 having various shapes according to the arrangement and the flow path shape can be produced at a relatively low cost.

  Therefore, since this trichlorosilane manufacturing apparatus is configured using the above-mentioned heat and corrosion resistant member, it is possible to extend the life of the reaction cylinder walls 9a to 9d and the both supporting disks 11 and 12 which are apparatus constituent members. At the same time, the generation of impurities can be prevented over a long period of time. In particular, the reaction cylindrical walls 9a to 9d and the two supporting disks 11 and 12 with which the supply gas and the reaction product gas in the state of the highest reactivity among the apparatus constituent members are in contact with each other use the above heat and corrosion resistant members. Therefore, it is possible to suppress the deterioration of these wall surfaces, obtain a stable conversion reaction over a long period of time, prevent the generation of impurities over a long period of time, and obtain high-purity trichlorosilane.

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

  For example, the number of reaction cylinder walls is not limited to the case of both embodiments, and an appropriate number may be provided. However, if the number of reaction cylinder walls is large, the heat transfer area increases and energy efficiency increases. However, since the radiant heat from the heating mechanism 2 is difficult to be transmitted to the inside and the heating effect decreases, The number of sheets is set to an appropriate number according to the size of the entire apparatus. Moreover, in the said embodiment, the notch part 10 is formed in the reaction cylinder wall, both upper and lower support discs 11 and 12 as a diverter are made flat, and it is made gas to the notch part 10 colliding with this support discs 11 and 12 Although the gas flow is folded back by inserting the reaction cylinder wall, a groove wider than the thickness of the reaction cylinder wall is formed on both support disks without providing a notch in the reaction cylinder wall. It may be configured to be formed in an annular shape having the same diameter and be folded back through the groove.

  Also, a cooling path may be added by forming a refrigerant path through which a refrigerant such as water flows inside the wall of the storage container.

  Further, the reaction cylinder wall of the above embodiment is formed of a heat-resistant and corrosion-resistant member in which a diamond coating film is formed on the surface of a carbon material, but at least the surface is formed of diamond or diamond-like carbon. Alternatively, other heat and corrosion resistant members may be used. Other heat and corrosion resistant members include a heat resistant and corrosion resistant member made of a solid diamond material, a heat resistant and corrosion resistant member (1) formed by forming a diamond or diamond-like carbon coating film on the surface of a solid diamond material, and carbonization. A heat-resistant and corrosion-resistant member (2) configured by forming a diamond or diamond-like carbon coating film on the surface of a silicon material, and a silicon carbide coating film formed on the surface of the carbon material, and further diamond or Any of the heat-resistant and corrosion-resistant members (3) formed by forming a diamond-like carbon coating film is employed. Even if these other heat-resistant and corrosion-resistant members are adopted, the deterioration of the members is suppressed and a stable conversion reaction is obtained over a long period of time, and the generation of impurities is prevented over a long period of time, as in the case of the above-described embodiment. Chlorosilane can be obtained.

  In the heat and corrosion resistant member (1), the surface is not a solid material but is formed of a coating film of diamond or diamond-like carbon, so that the surface can have a dense structure with fewer impurities. Therefore, the surface supply gas and the reaction product gas can be kept clean, and the life can be further increased.

Moreover, in the said heat-and-corrosion-resistant member (2), since the silicon carbide material is used as the base material, the life can be further extended compared with the case where the carbon material is used as the base material. In addition, carbon material and base material
Compared to the case, strong adhesion can be obtained between the base material and the coating film, and a denser coating film can be formed.

  Moreover, since the said heat-and-corrosion-resistant member (3) uses the carbon material as a base material, the member of various shapes can be produced comparatively cheaply. In addition, when a silicon carbide coating film is formed and a diamond or diamond-like carbon coating film is formed on the surface thereof, a diamond or diamond-like carbon coating film is formed on a carbon material as a base material. As compared with the above, it is possible to obtain strong adhesion between the substrate and the coating film, and it is possible to form a denser coating film.

  In addition, each of the above heat-resistant and corrosion-resistant members is not limited to the wall material of the reaction vessel (such as the reaction tube wall) and the both support disks (diverters) 11 and 12, but is installed in the insulating member, the sealing material, the heating mechanism 2, and the reaction vessel. It may be used for a heating medium or a heat insulating material 5.

1 is a simplified cross-sectional view showing a first embodiment of a trichlorosilane production apparatus according to the present invention. It is arrow sectional drawing which follows the AA line of FIG. It is arrow sectional drawing which follows the BB line of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Reaction container, 2 ... Heating mechanism, 3 ... Gas supply pipe, 4 ... Gas outlet pipe, 5 ... Thermal insulation, 6 ... Storage container, 8a-8d ... Small space, 9a-9d ... Reaction cylinder wall, 10 ... Notch , 11 ... Lower support disk (diverter), 12 ... Upper support disk (diverter), 20 ... Reaction channel

Claims (7)

A heat and corrosion resistant member disposed in an environment in which a mixed gas containing tetrachlorosilane and hydrogen contacts under high temperature,
A heat and corrosion resistant member characterized in that at least the surface is formed of diamond or diamond-like carbon. The heat and corrosion resistant member according to claim 1,
A heat and corrosion resistant member characterized in that a coating film of diamond or diamond-like carbon is formed on the surface of a carbon material. The heat and corrosion resistant member according to claim 1,
A heat-resistant and corrosion-resistant member characterized in that a coating film of diamond or diamond-like carbon is formed on the surface of a silicon carbide material. The heat and corrosion resistant member according to claim 1,
A heat-resistant and corrosion-resistant member characterized in that a silicon carbide coating film is formed on a surface of a carbon material, and further a diamond or diamond-like carbon coating film is formed on the surface. A trichlorosilane production apparatus for generating a reaction product gas containing trichlorosilane and hydrogen chloride by converting a feed gas containing tetrachlorosilane and hydrogen at a high temperature,
An apparatus for producing trichlorosilane, comprising the heat and corrosion resistant member according to any one of claims 1 to 4. A trichlorosilane production apparatus for generating a reaction product gas containing trichlorosilane and hydrogen chloride by converting a feed gas containing tetrachlorosilane and hydrogen at a high temperature,
A reaction vessel in which the supply gas is supplied to generate the reaction product gas;
An apparatus for producing trichlorosilane, characterized in that the reaction vessel is configured using the heat and corrosion resistant member according to any one of claims 1 to 4. A trichlorosilane production apparatus for generating a reaction product gas containing trichlorosilane and hydrogen chloride by converting a feed gas containing tetrachlorosilane and hydrogen at a high temperature,
A reaction vessel in which the supply gas is supplied to generate the reaction product gas is provided, and a diverter for changing a flow direction of the supply gas or the reaction product gas is provided in the reaction vessel,
An apparatus for producing trichlorosilane, wherein the diverter is formed of the heat-resistant and corrosion-resistant member according to any one of claims 1 to 4.

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