WO2012086777A1

WO2012086777A1 - Device for producing silicon and method for producing silicon

Info

Publication number: WO2012086777A1
Application number: PCT/JP2011/079866
Authority: WO
Inventors: 中原勝正; 近藤雅史; 武内喜則; 榊大介
Original assignee: 旭硝子株式会社; 株式会社キノテック・ソーラーエナジー
Priority date: 2010-12-22
Filing date: 2011-12-22
Publication date: 2012-06-28
Also published as: JP2014040330A

Abstract

As the temperature of part of a reactor (10) in a heater (22) is set to within the deposition temperature range for silicon, silicon tetrachloride gas is supplied to the interior of the reactor from a silicon tetrachloride gas supply opening (16a), zinc gas is supplied to the interior of the reactor vessel from a zinc gas supply opening (18a), the silicon tetrachloride is reduced with the zinc in the reactor, and a silicon deposition region (S) for depositing silicon on a wall section corresponding to the region set to within the silicon deposition temperature range in the reactor is formed. Then, a peeling mechanism (24) peels the silicon deposited in the silicon deposition region by moving a rod-shaped member (24b) on the silicon deposited in the silicon deposition region.

Description

Silicon manufacturing apparatus and silicon manufacturing method

The present invention relates to a silicon manufacturing apparatus and a silicon manufacturing method, and more particularly to a silicon manufacturing apparatus and a silicon manufacturing method for forming a silicon deposition region in a reactor or an inner tube thereof.

As a general method for producing high-purity silicon, a Siemens method is known in which silicon is produced by chemical vapor deposition using a silane compound such as trichlorosilane obtained by reacting crude silicon with hydrogen chloride. Yes. According to the Siemens method, extremely high-purity silicon can be obtained, but not only the rate of the silicon production reaction is extremely slow but also the yield is low, so a large-scale facility is required to obtain a certain production capacity. In addition to being required, the power consumption required for production is as high as 350 kWh per kg of high-purity silicon. In other words, high-purity silicon produced by the Siemens method is suitable for high-value-added highly integrated electronic devices that require a purity of 11-nine or higher, but the market is expected to expand rapidly in the future. As silicon for solar cells, it is expensive and excessive quality.

On the other hand, the zinc reduction method using silicon tetrachloride as a raw material and reducing silicon tetrachloride with metallic zinc at a high temperature is said to have been proved in principle in the 1950s. However, high purity silicon comparable to the Siemens method is used. It was considered difficult to obtain. However, in recent years, as silicon for solar cells, silicon having a purity of about 6-nine is sufficient, and a silicon having a purity as high as that for highly integrated electronic devices has become unnecessary, and in order to respond to rapid market expansion. As a manufacturing method for obtaining silicon at a low cost with a compact facility, the zinc reduction method has been reviewed again, and the manufacturing method has been studied again. Of course, it is possible to divert silicon scraps and off-spec manufactured by the Siemens method for solar cell applications, but there are certain limits to securing silicon production and reducing costs, and manufacturing at low cost. There is an urgent need to develop a zinc reduction method that can secure the amount.

Under such circumstances, as a zinc reduction method, while supplying zinc gas laterally from the zinc gas inlet, silicon tetrachloride gas is laterally supplied from the silicon tetrachloride gas inlet below the zinc gas inlet. And the structure which produces | generates a silicon | silicone is proposed as it progresses to a horizontal direction from a zinc gas inlet and a silicon tetrachloride gas inlet (refer patent document 1).

Further, as a zinc reduction method, a configuration in which heated silicon tetrachloride gas and zinc gas are brought into contact with each other to deposit solid silicon on a jet port of a silicon tetrachloride gas supply pipe has been proposed (see Patent Document 2).

JP 2004-196642 A JP 2007-145663 A

However, according to the study of the present inventor, in the configuration proposed in Patent Document 1, it seems that silicon is generated as it proceeds in the lateral direction from the zinc gas inlet and the silicon tetrachloride gas inlet. However, the way to commercialization is unclear.

In addition, in the configuration proposed in Patent Document 2, since solid silicon is only deposited at the outlet of the silicon tetrachloride gas supply pipe, the silicon production region is narrow and its yield is naturally limited. It is difficult to maintain the low cost and secure the production amount of silicon.

Further, according to the study of the present inventor, after silicon is deposited on the inner wall surface of the reaction tube, shock blow gas is blown off to such silicon to be peeled off and dropped and recovered in a lower silicon recovery tank. This is preferable from the viewpoint of increasing the production amount.

However, when such a configuration is adopted and the shock blow gas is blown to the interface between the inner wall surface of the reaction tube and silicon when the temperature of the shock blow gas is relatively low, the heat of the material constituting the reaction tube Due to the difference between the expansion coefficient and the thermal expansion coefficient of silicon, stress is generated on the inner wall surface of the reaction tube, and a part of the inner wall surface of the reaction tube is peeled off and falls downward together with the silicon. It has been found that the material constituting the reaction tube (for example, quartz) tends to be mixed.

Here, if the shock blow gas is heated and blown to the same high temperature as the reaction tube or silicon, such a situation can be avoided. However, for that purpose, it is necessary to use a high temperature and high pressure shock blow gas, and the load on the equipment is large. Tend to be.

The present invention has been made in view of such circumstances, and can produce polycrystalline silicon at a low cost and with high yield, and suppresses mixing of materials of members having a surface on which silicon is deposited. It is another object of the present invention to provide an expandable silicon manufacturing apparatus and silicon manufacturing method that enables continuous and efficient recovery of polycrystalline silicon.

In order to achieve the above object, a silicon production apparatus according to the first aspect of the present invention includes a reactor standing in a vertical direction, a silicon tetrachloride gas supply port connected to the reactor, A silicon tetrachloride gas supply pipe for supplying silicon tetrachloride gas into the reactor from a silicon chloride gas supply port; a zinc gas supply port communicating with the reactor; and zinc gas from the zinc gas supply port A zinc gas supply pipe to be supplied into the reaction vessel, a heater for heating the reactor, a bar member that enters the reactor, and a peeling mechanism that can move the bar member in the vertical direction; The silicon tetrachloride gas is supplied into the reactor from the silicon tetrachloride gas supply port while the temperature of a part of the reactor is set within a silicon deposition temperature range by the heater. The zinc gas supply port Zinc gas is supplied into the reaction vessel, silicon tetrachloride is reduced with zinc in the reactor, and silicon is formed on the wall corresponding to the region set in the silicon deposition temperature range in the reactor. After the formation of the silicon deposition region where the silicon deposits, the peeling mechanism is configured to peel the silicon deposited in the silicon deposition region by moving the rod member against the silicon deposited in the silicon deposition region. .

Further, according to the present invention, in addition to the first aspect, the peeling mechanism further includes an elastic tube which is an elastic member through which the rod member is inserted and seals the inside, and a weight capable of applying a load to the elastic tube. The second aspect is to include

In addition to the first or second aspect, the present invention has a third aspect that the rod member extends in the vertical direction and is movable while facing the silicon deposition region. .

In addition to any one of the first to third aspects, the present invention further includes an inner tube that is detachably inserted inside the reactor, and the silicon deposition region is formed by depositing the silicon. The fourth aspect is the inner wall surface of the inner tube in the reactor corresponding to the region set in the temperature range.

In addition to the fourth aspect, the present invention further includes a plate-like member connected to the inner wall surface of the inner tube, wherein the silicon deposition region is set to the silicon deposition temperature range. It is a 5th situation to include the wall surface of the said plate-shaped member corresponding to.

According to another aspect of the present invention, there is provided a silicon production method comprising: a reactor erected in a vertical direction; a silicon tetrachloride gas supply port connected to the reactor; and a tetrachloride from the silicon tetrachloride gas supply port. A silicon tetrachloride gas supply pipe for supplying silicon gas into the reactor, and a zinc gas supply port communicating with the reactor, and zinc gas for supplying zinc gas into the reaction vessel from the zinc gas supply port In the heater, using a silicon manufacturing apparatus comprising a supply pipe, a heater for heating the reactor, and a peeling mechanism having a rod member, the rod member being movable in the vertical direction, While setting the temperature of a part of the reactor within the silicon deposition temperature range, silicon tetrachloride gas is supplied into the reactor from the silicon tetrachloride gas supply port, and zinc gas is supplied from the zinc gas supply port. The reaction vessel A silicon precipitation region where silicon tetrachloride is reduced with zinc in the reactor and silicon is deposited on the wall corresponding to the region set in the silicon deposition temperature range in the reactor. After forming, the peeling mechanism peels the silicon deposited in the silicon deposition region by moving the rod member against the silicon deposited in the silicon deposition region.

According to the silicon manufacturing apparatus of the first aspect of the present invention, the peeling mechanism moves while applying the rod member to the silicon deposited on the silicon deposition region, so that the silicon deposited on the silicon deposition region is peeled off. Polycrystalline silicon can be produced with good yield at low cost, and polycrystal silicon can be recovered continuously and efficiently while suppressing the material of the member having the surface on which silicon is deposited. A scalable configuration that can be implemented. Such an effect is also obtained in the silicon manufacturing method according to another aspect of the present invention.

According to the configuration of the second aspect of the present invention, the peeling mechanism further includes an expansion tube that is an elastic member that is inserted through the rod member and seals the inside, and a weight that can apply a load to the expansion tube. Therefore, the rod member can be efficiently moved with a simple configuration using the elastic force of the expansion tube and the load of the weight while maintaining the airtightness inside the reactor, and silicon is deposited. The polycrystalline silicon can be peeled and recovered continuously and efficiently while suppressing the mixing of the material of the member.

According to the configuration of the third aspect of the present invention, the rod member extends in the vertical direction and is movable while facing the silicon precipitation region, so that it can reliably hit the silicon in the silicon precipitation region, Polycrystalline silicon can be peeled and recovered continuously and efficiently while suppressing the mixing of the material of the member on which silicon is deposited.

According to the configuration of the fourth aspect of the present invention, since the silicon precipitation region can be defined on the inner wall surface of the inner tube that is detachably inserted into the reactor, the yield of silicon can be increased and the inner wall surface deteriorated. Since the inner tube can be easily replaced, the production of polycrystalline silicon can be continued without replacing the reactor itself.

According to the configuration of the fifth aspect of the present invention, the silicon precipitation region can be expanded by the surface area of the wall surface of the plate-like member connected to the inner wall surface of the inner tube, so that the silicon yield can be further increased. .

It is a typical longitudinal section of a silicon manufacture device in an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the silicon manufacturing apparatus in the present embodiment, and corresponds to the AA cross-sectional view of FIG. FIG. 2 is a schematic enlarged cross-sectional view of a zinc gas supply pipe of a silicon manufacturing apparatus in the present embodiment, which corresponds to the BB cross-sectional view of FIG. FIG. 2 is a schematic enlarged cross-sectional view of a silicon tetrachloride gas supply pipe of the silicon manufacturing apparatus in the present embodiment, and corresponds to the CC cross-sectional view of FIG. FIG. 6 is a schematic enlarged cross-sectional view of an inner tube of a silicon manufacturing apparatus in a modification of the present embodiment, and corresponds in position to the EE cross-sectional view of FIG. FIG. 10 is a schematic enlarged cross-sectional view of an inner tube of a silicon manufacturing apparatus according to another modification of the present embodiment, and corresponds to the EE cross-sectional view of FIG. 1 in the same manner as FIG. 4A. FIG. 10 is a schematic enlarged longitudinal sectional view of a rod member of a silicon manufacturing apparatus in still another modified example of the present embodiment, and corresponds to a GG sectional view of FIG. 5B. FIG. 5B is a schematic enlarged cross-sectional view of a bar member of a silicon manufacturing apparatus in still another modified example of the present embodiment, and corresponds to the FF cross-sectional view of FIG. 5A.

Hereinafter, a silicon manufacturing apparatus and method according to an embodiment of the present invention will be described in detail with reference to the drawings as appropriate. In the figure, the x-axis, y-axis, and z-axis form a three-axis orthogonal coordinate system, the z-axis indicates the vertical direction that is the vertical direction, and the negative direction of the z-axis is downward and downstream. To do.

FIG. 1 is a schematic longitudinal sectional view of a silicon manufacturing apparatus in the present embodiment. FIG. 2 is a schematic cross-sectional view of the silicon manufacturing apparatus in the present embodiment, and corresponds to the AA cross-sectional view of FIG. 3A is a schematic enlarged cross-sectional view of the zinc gas supply pipe of the silicon manufacturing apparatus in the present embodiment, which corresponds to the BB cross-sectional view in FIG. 1, and FIG. 3B shows the silicon manufacturing in the present embodiment. FIG. 2 is a schematic enlarged cross-sectional view of a silicon tetrachloride gas supply pipe of the apparatus, which corresponds to the CC cross-sectional view of FIG.

As shown in FIGS. 1 and 2, the silicon manufacturing apparatus 1 is typically cylindrical and coaxial with the central axis C parallel to the z axis and extends in the vertical direction. The reactor 10 in which the reduction reaction reduced with zinc occurs. The reactor 10 is typically made of quartz, and an insertion hole 10a is formed in the vertical wall thereof. Further, the upper end of the reactor 10 is closed by a disk-shaped upper lid 12 typically made of quartz and fixed thereto, and a connecting member 30 is provided at the lower end of the reactor 10.

Here, in the silicon production apparatus 1, the reactor 10 is a vertical reactor in which the length L of the mating surface to the upper lid 12 and the mating surface to the connecting member 30 is longer than the diameter D. In the reactor 10, zinc gas is supplied above (upstream side) from the silicon tetrachloride gas, and the temperature of the reactor 10 is appropriately set to cause a reduction reaction to deposit silicon. The precipitation region is defined below (downstream side) from the portion to which silicon tetrachloride gas is supplied, and silicon can be recovered from below (more downstream side) of the reactor 10.

Specifically, as shown in FIG. 2, the upper lid 12 that closes the upper open end of the reactor 10 has one insertion hole 12a coaxially with the central axis C in the central region, and adjacent insertion holes. A plurality of insertion holes 12b and a plurality of insertion holes 12c are formed so as to surround 12a.

In one insertion hole 12a, a zinc gas supply pipe 18 typically made of quartz is inserted and fixed in contact with a zinc gas supply source (not shown). The zinc gas supply pipe 18 penetrates into the reactor 10, extends vertically downward coaxially with the central axis C, and opens in the direction perpendicular to the central axis C at the lower end of the vertical wall. While having the zinc gas supply port 18a to be operated, the vertical tip thereof is closed. In addition, as a zinc gas supply source, the structure which introduce | transduces a zinc wire into the part extended in the perpendicular direction of this zinc gas supply pipe | tube 18, and heats and evaporates a zinc wire more than a boiling point with the heater mentioned later for details May be employed, or an independent zinc gas supply device may be employed. If necessary, the zinc gas supply pipe 18 can be mixed with an inert gas from an inert gas source (not shown).

As shown in FIG. 3A, it is preferable that a plurality of zinc gas supply ports 18a of the zinc gas supply pipe 18 are provided. Typically, the zinc gas supply ports 18a are symmetrical with respect to the central axis C at an equal interval of 120.degree. It is preferable to open three at the lower end. This is because the zinc gas is discharged into the reactor 10 in the horizontal direction and more reliably diffuses evenly, so that the mixing of the zinc gas and the silicon tetrachloride gas can be performed better. Of course, when zinc gas and silicon tetrachloride gas are mixed well, only one zinc gas supply port 18a of the zinc gas supply pipe 18 may be provided, or the vertical direction of the zinc gas supply pipe 18 may be increased. The tip in the direction may be opened.

The plurality of insertion holes 12b are typically provided at three equal intervals from the central axis C and at equal intervals of 120 ° in the circumferential direction of the upper lid 12. In each of the insertion holes 12b, an inert gas supply pipe 14 that is typically made of quartz is inserted into and fixed to an inert gas supply source (not shown), and the inert gas supply pipe is fixed. 14 has an inert gas supply port 14a which penetrates into the reactor 10 and extends vertically downward in parallel to the central axis C and is an opening opened at the lower end thereof. Further, inside the inert gas supply pipe 14, a single silicon tetrachloride gas supply pipe 16 typically made of quartz is provided in contact with a silicon tetrachloride gas supply source (not shown). The silicon tetrachloride gas supply pipe 16 penetrates into the reactor 10 and extends vertically downward in parallel with the central axis C. The silicon tetrachloride gas supply pipe 16 has a silicon tetrachloride gas supply port 16a opened at a lower end portion of the vertical wall in a direction orthogonal to the central axis C, while its vertical end is closed. Yes. In addition, the silicon tetrachloride gas supply pipe | tube 16 can be connected to the inert gas supply source which abbreviate | omits illustration as needed.

As shown in FIG. 3B, the silicon tetrachloride gas supply port 16a of the silicon tetrachloride gas supply pipe 16 only needs to be opened at an arbitrary position and an arbitrary number at the lower end of the vertical wall (in the drawing, as an example, (Only one opening facing the inner wall of the inner tube 26 is shown). This is because it is sufficient that the silicon tetrachloride gas is discharged in the horizontal direction from the viewpoint of the mixing of zinc gas and silicon tetrachloride gas.

The plurality of insertion holes 12c are typically equidistant from the central axis C and are provided at equal intervals of 120 ° in the circumferential direction of the upper lid 12 so as to sandwich the corresponding insertion holes 12b. The insertion tube 24a of the peeling mechanism 24, which will be described in detail later, is inserted and fixed in each insertion hole 12c.

In this way, one zinc gas supply pipe 18 is inserted into the center of the upper lid 12 to extend the inside of the reactor 10, and the silicon tetrachloride gas supply included in the plurality of inert gas supply pipes 14 is surrounded by the zinc gas supply pipe 18. The reason for adopting the configuration in which the pipe 16 is disposed is that the zinc gas having a boiling point of 910 ° C. needs to be introduced into the reactor 10 in a state of being heated to a higher temperature than the silicon tetrachloride gas having a boiling point of 59 ° C. Therefore, although the diameters of the reactor 10 and the upper lid 12 tend to be slightly larger, the zinc gas maintained at a relatively high temperature can be reliably ensured in the radial direction in the reactor 10 while making the configuration of the entire apparatus more compact. This is because the convenience of introducing the silicon tetrachloride gas in a distributed manner around the central portion is considered. If the diameter of the reactor 10 or the upper lid 12 can be further increased, a plurality of zinc gas supply pipes 18 may be provided in the central region of the upper lid 12.

Here, the inert gas supply port 14a opens to the inside of the reactor 10 at a position of a length L1 from the mating surface to the upper lid 12 of the reactor 10. Further, the silicon tetrachloride gas supply port 16a opens to the inside of the reactor 10 at a position of a length L2 (L2> L1) from the mating surface to the upper lid 12 of the reactor 10. Further, the zinc gas supply port 18a opens to the inside of the reactor 10 at a position of a length L3 (L3 <L2) from the mating surface to the upper lid 12 of the reactor 10. That is, the opening position (lower end position) of the inert gas supply port 14a is above the opening position (typically the center position) of the silicon tetrachloride gas supply port 16a. Moreover, the opening position (typically the central position) of the zinc gas supply port 18a is above the opening position of the silicon tetrachloride gas supply port 16a, and below the opening position of the inert gas supply port 14a. (L1 <L3 <L2).

An exhaust pipe 20 typically made of quartz is inserted into an insertion hole 10a provided in the vertical wall of the reactor 10 in communication with an exhaust gas processing device (not shown). The exhaust pipe 20 is preferably welded through the insertion hole 10a of the reactor 10 and configured integrally with the reactor 10 in terms of durability. Further, the end of the exhaust pipe 20 on the side of the reactor 10 has an exhaust inlet 20 a that opens in the reactor 10.

Also, the vertical wall of the reactor 10 is surrounded by a heater 22 from the outside. The heater 22 is a typically cylindrical electric furnace coaxial with the central axis C, and has a first heating part 22a, a second heating part 22b, and a third heating part 22c in the vertical downward direction. The third heating unit 22c is provided with a through hole 22d through which the exhaust pipe 20 passes.

Furthermore, a typically cylindrical inner tube 26 extending coaxially with the central axis C is inserted into the reactor 10 along the inner wall thereof. The inner tube 26 is typically made of quartz and is detachable from the reactor 10, and the inner wall surface of the inner tube 26 becomes a precipitation region S in which polycrystalline silicon is deposited.

Specifically, the upper end 26a of the inner pipe 26 is an open end and is at a position of a length L4 from the mating surface to the upper lid 12 of the reactor 10, and the inert gas supply port of the inert gas supply pipe 14 While the opening position of 14a is above the upper end 26a of the inner pipe 26, it is above the opening positions of the silicon tetrachloride gas supply port 16a and the silicon tetrachloride gas supply port 16a of the silicon tetrachloride gas supply pipe 16. Each opening position of the zinc gas supply port 18a of the zinc gas supply pipe 18 is located below the upper end 26a of the inner pipe 26 (L1 <L4 <L3 <L2).

Thus, the opening position of the silicon tetrachloride gas supply port 16a of the silicon tetrachloride gas supply pipe 16 and the opening position of the zinc gas supply port 18a of the zinc gas supply pipe 18 are lower than the upper end 26a of the inner pipe 26. The reason for this is that by adopting a configuration in which the zinc gas supply pipe 18 is inserted into the center of the upper lid 12 and the inside of the reactor 10 is extended, it is simple without providing an insertion hole in the vertical wall of the inner pipe 26. In addition to the fact that the zinc gas supply port 18a can be disposed below in a simple configuration, the zinc gas is also discharged inside the inner pipe 26 in addition to the silicon tetrachloride gas, so that the reactor 10 The deposition region S can be reliably defined on the inner wall surface of the inner tube 26 by reliably suppressing the phenomenon that the gas diffuses and penetrates unnecessarily in the gap between the vertical inner wall of the inner tube 26 and the outer wall of the inner tube 26. This is because of this.

Further, since the lower end of the inner pipe 26 is supported by the connecting member 30 and extends downward beyond the exhaust pipe 20, the reaction is performed so as not to unnecessarily block the exhaust inlet 20 a of the exhaust pipe 20. An insertion hole 26 b is provided at a position corresponding to the insertion hole 10 a of the container 10. That is, the exhaust pipe 20 is fixed by being inserted into the insertion hole 10 a provided in the vertical wall of the reactor 10 and the insertion hole 26 b provided in the vertical wall of the inner pipe 26.

Moreover, since the inner tube 26 is heated and maintained at a high temperature such as a temperature of 1000 ° C. or higher and 1100 ° C. or lower by the second heating unit 22b and the third heating unit 22c in the heater 22, the outer wall surface reacts. Considering that there is a possibility that they may stick to each other and cannot be removed when they are in contact with the inner wall surface of the reactor 10, they are juxtaposed to the reactor 10 via a predetermined gap. In order to stably maintain such a gap, it is typically preferable to install a quartz spacer.

More specifically, in the heater 22, the first heating unit 22 a is a heating unit that can be heated and maintained so as to exhibit a temperature (for example, 1200 ° C.) that exceeds the deposition temperature at which silicon is deposited. Vertical wall of the reactor 10 in which an inert gas supply pipe 14 having a port 14a, a silicon tetrachloride gas supply pipe 16 having a silicon tetrachloride gas supply port 16a, and a zinc gas supply pipe 18 having a zinc gas supply port 18a are arranged. Then, surrounding the vertical wall of the corresponding inner tube 26 and the inside thereof, the region is heated and maintained at a temperature exceeding the deposition temperature at which silicon is deposited.

Here, the range of 950 ° C. or higher and 1100 ° C. or lower can be evaluated as a suitable temperature range as the range of the deposition temperature at which silicon is deposited. This is because when the vertical wall of the reactor 10, the vertical wall of the inner tube 26, and the temperature inside thereof are lower than 950 ° C., the reaction rate of the reduction reaction in which silicon tetrachloride is reduced with zinc is slowed down. Thus, when the vertical wall of the reactor 10, the vertical wall of the inner tube 26, and the temperature inside thereof exceed 1100 ° C., it is more stable that silicon exists as a compound gas of silicon tetrachloride than when it exists as a solid. This is because it is considered that such a reduction reaction itself does not occur. Further, since the boiling point of zinc is 910 ° C., the range of the deposition temperature at which such silicon is deposited is a temperature range exceeding the boiling point of zinc.

Further, the second heating unit 22b and the third heating unit 22c provided continuously below the second heating unit 22b are heating units that can be heated and maintained so as to exhibit a temperature within the silicon deposition temperature range, and are inactive. The vertical wall of the reactor 10 in which the gas supply pipe 14, the silicon tetrachloride gas supply pipe 16 and the zinc gas supply pipe 18 are not disposed, the vertical wall of the inner pipe 26 corresponding thereto, and the inside thereof are continuously covered up and down. The region is heated and maintained at the deposition temperature at which silicon is deposited.

Here, the second heating unit 22b is below the portion heated by the first heating unit 22a, and the vertical wall of the reactor 10 at a temperature (for example, 1100 ° C.) within the range of the deposition temperature at which silicon is deposited, It is a heating unit capable of heating the vertical wall of the inner tube 26 and the inside thereof. In addition, the third heating unit 22c has a temperature lower than the heating temperature of the second heating unit 22b (for example, 1000) within the range of the deposition temperature at which silicon is deposited below the portion heated by the second heating unit 22b. It is a heating section capable of heating the vertical wall of the reactor 10, the vertical wall of the inner tube 26, and the inside thereof at a temperature of ° C.

The second heating unit 22b exhibits an intermediate heating temperature that connects the heating temperature of the first heating unit 22a and the heating temperature of the third heating unit 22c, but may be omitted as necessary. In other words, the vertical wall of the reactor 10 and the corresponding inner pipe 26 in the portion where the silicon tetrachloride gas supply pipe 16 having the silicon tetrachloride gas supply opening 16a and the zinc gas supply pipe 18 having the zinc gas supply opening 18a are arranged. A reactor in a portion where the silicon tetrachloride gas supply pipe 16 and the zinc gas supply pipe 18 are not arranged vertically below the first heating section 22a that heats the vertical wall and the inside thereof at a temperature exceeding the deposition temperature at which silicon is deposited. What is necessary is just to provide the heating part which heats the vertical wall of 10 vertical walls, the corresponding vertical wall of the inner pipe | tube 26, and the inside in the precipitation temperature range which silicon precipitates. In addition, the 2nd heating part 22b also has a function which adjusts so that the difference of the heating temperature of the 1st heating part 22a and the heating temperature of the 3rd heating part 22c may not become excessive, The temperature of the vertical wall etc. of the inner tube | pipe 26, etc. An excessive change can be suppressed.

In addition, all of the heating temperature of the 1st heating part 22a in the heater 22, the 2nd heating part 22b, and the 3rd heating part 22c all exceed 910 degreeC which is the boiling point of zinc.

Further, from the viewpoint of increasing the silicon deposition rate on the inner wall surface of the inner tube 26, the inner tube 26 is located within the inner tube 26 at a location corresponding to the deposition region S as shown in FIGS. 4A and 4B. It is preferable to include plate-like members 28 and 28 'connected to the wall surface.

FIG. 4A is a schematic enlarged cross-sectional view of an inner tube of a silicon manufacturing apparatus according to a modification of the present embodiment, and corresponds in position to the EE cross-sectional view of FIG. FIG. 4B is a schematic enlarged cross-sectional view of an inner tube of a silicon manufacturing apparatus according to another modification of the present embodiment, and corresponds to the EE cross-sectional view of FIG. 1 in the same manner as FIG. 4A.

The plate-like member 28 shown in FIG. 4A is typically a flat plate member that is connected to the inner wall surface of the inner tube 26 and extends radially from the inner wall surface toward the central axis C. A total of three pieces are arranged around at an interval of 120 ° and are in contact with each other in the vicinity of the central axis C. Thereby, in addition to the inner wall surface of the inner pipe 26, the wall surface of the plate-like member 28 also becomes a silicon deposition surface, and the silicon deposition area can be increased, contributing to an increase in the silicon deposition rate. In this case, it is more preferable that the plate-like member 28 is positioned vertically below the silicon tetrachloride gas supply pipe 16 so that the distance from the silicon tetrachloride gas supply port 16a is relatively short.

Further, when it is not necessary to increase the silicon deposition surface to the extent shown in FIG. 4A, a plate-like member 28 'shown in FIG. 4B may be provided. The plate-like member 28 ′ is typically a flat plate member connected to the inner wall surface of the inner tube 26 and extending radially from the inner wall surface toward the central axis C. The arrangement of a total of three sheets at 120 ° intervals is the same as that of the plate-like member 28, except that it does not reach the vicinity of the central axis C and is separated from each other.

In addition, as for the length in the vertical direction of the plate-like members 28 and 28 ', an effect can be obtained even if the length occupies a part of the precipitation region S, but from the viewpoint of increasing the precipitation area, the entire precipitation region S is used. It is preferable to adopt the occupied length. It should be noted that an appropriate number of the plate-

like members

28 and 28 ′ can be provided as long as they do not interfere with each other in the inner tube 26.

The peeling mechanism 24 is a mechanism for peeling the polycrystalline silicon deposited on the precipitation region S on the inner wall surface of the inner tube 26 attached to the reactor 10 and dropping it downward under its own weight. The introduction pipe 24a is inserted and fixed to 12c.

More specifically, the peeling mechanism 24 includes a rod member 24b typically made of quartz that is inserted through an introduction tube 24a fixed to each insertion hole 12c so as to be vertically movable and extends in parallel with the central axis C. . The rod member 24b penetrates into the reactor 10 and interferes with the polycrystalline silicon layer deposited on the deposition region S on the inner wall surface of the inner tube 26, but it interferes unnecessarily with the inner wall surface of the inner tube 26 itself. In order to prevent this, the inner wall 26 of the inner tube 26 extends in parallel and faces the inner wall surface of the inner tube 26 while being separated by a predetermined distance. The shape of the rod member 24b is typically a columnar shape when the inner tube 26 is cylindrical, and is typically a prismatic shape when the inner tube 26 is a rectangular tube.

Further, the peeling mechanism 24 is interposed between the upper end portion of the introduction pipe 24a and the flange portion, which is the upper end portion of the rod member 24b, and seals an internal region through which the rod member 24b is inserted and has a predetermined spring constant. It has a bellows-like telescopic tube 24c that is an elastic member, a weight 24d that is placed on a flange that is the upper end of the rod member 24b, and an actuator 24e that communicates with the weight 24d. In the initial state, the telescopic tube 24c may be set in a compressed state in which the actuator 24e is engaged with the weight 24d at the lowest position so as to receive a load from the weight 24d and contract by a predetermined length. The non-compressed state may be set so as to exhibit a substantially natural length so that the load of the weight 24d is not substantially received by locking the 24d at the uppermost position. In addition, when the lower end part of the expansion / contraction tube 24c is brought into direct contact with the upper surface of the upper lid 12, the introduction tube 24a can be omitted.

In the peeling mechanism 24, when the telescopic tube 24c is set in the compressed state in the initial state, the rod member 24b is correspondingly at the lowest position, but the actuator 24e is operated to engage the weight 24d. The rod member 24b is moved upward by the pulling force of the actuator 24e while receiving the extension force of the extension tube 24c by lifting the extension tube 24c in a compressed state by releasing the stop and pulling it upward. Can move up to. When the bar member 24b moves to the uppermost position, the weight 24d is locked by the actuator 24e, and the bar member 24b is maintained at the uppermost position. Of course, when the rod member 24b is moved to the uppermost position, the actuator 24e may keep the weight 24d not locked when necessary. In such a case, the telescopic tube 24c is attached to the weight 24d. By contracting in response to the load, the bar member 24b can move downward to the lowest position, and then the bar member 24b repeats such an up / down movement as necessary. Is possible.

On the other hand, when the telescopic tube 24c is set to an uncompressed state in the initial state, the rod member 24b is correspondingly at the uppermost position, but the actuator 24e is operated to lock the weight 24d. By unwinding and applying the load of the weight 24d to the telescopic tube 24c and contracting, the rod member 24b moves downward to the lowest position by the load of the weight 24d while receiving the compression reaction force of the telescopic tube 24c. be able to. When the bar member 24b moves to the lowest position, the weight 24d is locked by the actuator 24e, and the bar member 24b is maintained at the lowest position. Of course, when the rod member 24b moves to the lowest position, the actuator 24e may pull up the weight 24d without being locked, if necessary. In such a case, the telescopic tube 24c is pulled up by the weight 24d. The rod member 24b can move upward and move to the uppermost position by being stretched without receiving the load, and thereafter, the rod member 24b performs such an up / down movement operation as necessary. It is possible to repeat.

Here, in the case where polycrystalline silicon is deposited in the precipitation region S on the inner wall surface of the inner tube 26, the bar member 24b is opposed to the lower tip and the precipitation region S by performing such vertical movement. The side surface mechanically hits the polycrystalline silicon typically formed of acicular crystals deposited in the precipitation region S, and the impact causes the acicular polycrystalline silicon to be removed from the precipitation region S, that is, from the inner wall surface of the inner tube 26. It can be folded and peeled and dropped by its own weight below the reactor 10.

That is, the bar member 24b is required to peel the polycrystalline silicon deposited in the silicon deposition region S and move it down below the reactor 10 by moving it up and down. The moving range in the vertical direction must be such that at least the lower tip can take a position between a position vertically above and a position vertically below the upper end of the silicon deposition region S. It is. In order to peel the polycrystalline silicon deposited in the silicon deposition region S more reliably, the lower end of the rod member 24b is moved from the lower end of the silicon deposition region S as the vertical movement range of the rod member 24b. It is more preferable to secure a moving range that reaches a position vertically below.

Further, as the structure of the rod member 24b, a larger contact area with the polycrystalline silicon deposited on the deposition region S on the inner wall surface of the inner tube 26 is preferable in peeling the polycrystalline silicon by mechanical impact. As shown in FIGS. 5A and 5B, it is desirable to provide a plate-like member 24f as a contact plate on the rod member 24b.

FIG. 5A is a schematic enlarged longitudinal sectional view of a rod member of a silicon manufacturing apparatus in still another modified example of the present embodiment, and corresponds to the GG sectional view of FIG. 5B. FIG. 5B is a schematic enlarged cross-sectional view of a bar member of a silicon manufacturing apparatus in still another modified example of the present embodiment, and corresponds to the FF cross-sectional view of FIG. 5A.

The plate-like member 24f shown in FIG. 5A and FIG. 5B is connected to the rod portion of the rod member 24b, and is typical so as to efficiently contact the polycrystalline silicon deposited on the precipitation region S on the inner wall surface of the inner tube 26. Has an arc shape centered on the central axis C when viewed in the vertical direction. The number of plate-like members 24f and the length of the arc shape can be appropriately set within a range in which the plate-like member 24f does not interfere with other components. Further, the number of the plate-like members 24f can be appropriately set within a range that does not interfere with other components. Further, the vertical position of the plate member 24f is such that the upper end of the plate member 24f is vertically above the upper end of the silicon precipitation region S and the lower end of the plate member 24f is the silicon precipitation region by the vertical movement of the bar member 24b. It is preferable to set so as to reach vertically below the lower end of S.

In addition, as an apparatus for moving the bar member 24b up and down, an apparatus including the telescopic tube 24c, the weight 24d, and the actuator 24e is shown. However, the present invention is not limited to this and is more expensive. A device such as an air cylinder may be used.

Furthermore, since the polycrystalline silicon deposited on the precipitation region S on the inner wall surface of the inner tube 26 is peeled off and falls downward due to its own weight, the connecting member 30 connected to the lower end of the reactor 10 is connected to the connecting member 30 connected to the lower end of the reactor 10. Are sequentially connected to the communication pipe 32, the valve device 34, and the silicon recovery tank 36.

Specifically, the communication pipe 32 communicates with the inside of the reactor 10 via the connecting member 30, and the valve device 34 is connected to the communication pipe 32.

The valve device 34 includes a valve 34 a that can shut off the internal environment and the external environment of the reactor 10. In a state where the valve 34a is closed in order to shut off the communication between the inside of the reactor 10 and the silicon recovery tank 36, the polycrystal which is peeled off by moving the bar member 24b of the peeling mechanism 24 up and down and falls by its own weight. Silicon can be deposited on the bulb 34a. On the other hand, when the valve 34a is opened, the inside of the reactor 10 communicates with the silicon recovery tank 36 provided below the valve device 34, and the polycrystalline silicon deposited on the valve 34a is transferred to the silicon recovery tank 36. It can be recovered by dropping it under its own weight.

Further, the silicon recovery tank 36 is installed in a room temperature atmosphere outside the heating region of the heater 22 and is detachable from the silicon manufacturing apparatus 1.

Next, a silicon manufacturing method for manufacturing polycrystalline silicon using the silicon manufacturing apparatus 1 having the above configuration will be described in detail. Note that a series of steps of the silicon manufacturing method may be automatically controlled by a controller having various databases or the like while referring to detection data from various sensors, or may be partly or wholly performed manually.

First, in a state where the valve 34a of the valve device 34 is closed and the inside and outside of the reactor 10 are shut off, an inert gas is supplied into the reactor 10 from the inert gas supply port 14a for a predetermined time, The reaction atmosphere inside the reactor 10 is adjusted. At this time, if necessary, an inert gas may be supplied from the silicon tetrachloride gas supply port 16a and the zinc gas supply port 18a for a predetermined time.

Next, the first heating unit 22a in the heater 22 causes the inert gas supply pipe 14 having the inert gas supply port 14a, the silicon tetrachloride gas supply pipe 16 having the silicon tetrachloride gas supply port 16a, and the zinc gas supply port. The vertical wall of the reactor 10 in which the zinc gas supply pipe 18 having 18a is arranged, the corresponding vertical wall of the inner pipe 26 and the inside thereof are heated, and this part is heated and maintained at a temperature exceeding the silicon deposition temperature. To do. At the same time, the vertical wall of the reactor 10 in which the inert gas supply pipe 14, the silicon tetrachloride gas supply pipe 16 and the zinc gas supply pipe 18 are not arranged by the second heating part 22b and the third heating part 22c in the heater 22, The corresponding vertical wall of the inner tube 26 and the inside thereof are heated, and this portion is heated and maintained within the silicon deposition temperature range.

Next, the reduction reaction step is performed while maintaining such temperature conditions. Specifically, silicon tetrachloride gas is supplied into the reactor 10 from the silicon tetrachloride gas supply port 16a, and zinc gas is supplied from the zinc gas supply port 18a. At this time, an inert gas may be supplied from the inert gas supply port 14a as necessary.

Then, a reduction reaction in which silicon tetrachloride is reduced with zinc can occur inside the reactor 10. However, since the silicon tetrachloride gas is a relatively heavy gas whose specific gravity is about 2.6 times the specific gravity of the zinc gas, the zinc gas above the opening position of the silicon tetrachloride gas supply port 16a. It cannot substantially diffuse up to the supply port 18a, and a reduction reaction occurs in the vicinity of the silicon tetrachloride gas supply port 16a inside the reactor 10 or in a region below it, so that solid silicon and zinc chloride gas are generated. It will be.

Further, here, the vertical wall of the reactor 10 where the inert gas supply pipe 14, the silicon tetrachloride gas supply pipe 16 and the zinc gas supply pipe 18 are not arranged, the corresponding vertical wall of the inner pipe 26 and the inside thereof are Since the second heating unit 22b and the third heating unit 22c are heated and maintained so as to exhibit a temperature in the silicon deposition temperature range, the silicon generated by the reduction reaction is below the vertical wall of the inner tube 26, That is, it precipitates as a needle-like crystal in the precipitation region S, which is a region below the silicon tetrachloride gas supply port 16a and above the exhaust introduction port 20a on the inner wall surface of the inner pipe 26. At this time, silicon is not deposited in the silicon tetrachloride gas supply port 16a and the zinc gas supply port 18a, and the supply port is not blocked by silicon.

Further, in this manner, in the precipitation region S in the lower portion of the inner wall surface of the inner tube 26, acicular silicon is deposited sequentially, and silicon grows using the deposited silicon as a seed crystal. A sufficient thickness of polycrystalline silicon will be deposited. Here, such a precipitation process and a crystal growth process related thereto are referred to as precipitation.

Next, after the reduction reaction is continued for a predetermined time, if polycrystalline silicon having a sufficient thickness is deposited in the precipitation region S in the lower portion of the inner wall surface of the inner tube 26, Stop supplying zinc gas. Then, with the inert gas supplied from the inert gas supply port 14a of the inert gas supply pipe 14 to the inside of the reactor 10, the atmosphere inside the reactor 10 is replaced with the inert gas.

Next, when the rod member 24b is moved up and down correspondingly by actuating the actuator 24e of the peeling mechanism 24 and releasing or locking the weight 24d to extend or compress the telescopic tube 24c, the tip and side surfaces thereof are The polycrystalline silicon deposited on the precipitation region S on the inner wall surface of the tube 26 is mechanically peeled off from the inner wall surface of the inner tube 26 by breaking the needle-like polycrystalline silicon by the impact, and the peeled material is moved downward by its own weight. Fall into. At this time, since the valve 34a is closed so as to shut off the inside and the outside of the reactor 10, the silicon that has fallen accumulates on the valve 34a.

When the peeling step for moving the rod member 24b up and down in this way is completed, the valve 34a is opened and the polycrystalline silicon deposited on the valve 34a is dropped into the silicon recovery tank 36 by its own weight, and then the reactor 10 While the valve 34a is closed again to shut off the inside of the silicon, the polycrystalline silicon in the silicon recovery tank 36 is taken out and recovered, and a series of steps of the present silicon manufacturing method is completed. Continuously, a series of steps of the next silicon manufacturing method is entered. Here, since the silicon recovery tank 36 is detachable with respect to the silicon manufacturing apparatus 1, when the silicon has finished dropping, the silicon recovery tank 36 is removed from the silicon manufacturing apparatus 1 after closing the valve 34a. It is also possible to move to a predetermined storage location and take out the polycrystalline silicon inside the silicon recovery tank 36.

Here, when a series of steps are repeated several times in such a silicon production method, the inner wall surface of the inner tube 26 deteriorates. Therefore, the inner tube 26 whose number of repetitions exceeds the reference number is determined from the reactor 10. It is removed and replaced with a new inner pipe 26.

In the above embodiment, the inner tube 26 is disposed in the reactor 10 in consideration of the convenience of replacement. However, if the reactor 10 itself can be replaced as appropriate, It is also possible to omit the inner tube 26 and set the silicon deposition region S directly on the inner wall surface of the reactor 10.

In the above-described embodiment, the configuration in which the zinc gas supply port 18a is disposed above the silicon tetrachloride gas supply port 16a has been described. However, the configuration is not limited to this, and the configuration is complicated. However, when the gas diffusibility and the like can be adjusted by controlling the gas discharge direction and flow velocity, the zinc gas supply port 18a is disposed at the same height or lower than the silicon tetrachloride gas supply port 16a. It is also possible to adopt such a configuration.

In the above embodiment, the material of the reactor, the upper lid, the connecting member, the inert gas supply pipe, the silicon tetrachloride gas supply pipe, the zinc gas supply pipe, the exhaust pipe, the inner pipe and the rod member is 950 ° C. Since the material must be resistant to silicon tetrachloride gas, zinc gas, by-product zinc chloride gas, etc. at high temperatures, quartz, silicon carbide, silicon nitride, etc. can be mentioned. From the standpoint of avoiding carbon and nitrogen contamination, quartz, specifically, quartz glass is most preferable. In addition, the material of the expansion tube is not particularly limited and may be made of metal or resin, but is preferably made of metal from the viewpoint of heat resistance.

In the above embodiment, examples of the inert gas include rare gases such as He gas, Ne gas, Ar gas, Kr gas, Xe gas, and Rn gas, nitrogen gas, and the like. From the standpoint of avoiding nitrogen contamination, a rare gas is preferable, and Ar gas, which is inexpensive, is most preferable.

Now, each experimental example and comparative example corresponding to this embodiment will be described in detail.

(Experimental example 1)
In Experimental Example 1, polycrystalline silicon was manufactured using the silicon manufacturing apparatus 1 of the present embodiment.

Specifically, in the silicon production apparatus 1, the quartz reactor 10 has an outer diameter D set to 226 mm (thickness is 3 mm, inner diameter is 220 mm) and length L is set to 2330 mm, and the quartz inner tube 26, the outer diameter is set to 206 mm (the wall thickness is 3 mm, the inner diameter is 200 mm), and the length L4 of the upper end 26a from the mating surface to the upper lid 12 of the reactor 10 is set to 50 mm. No. 18 has an outer diameter set to 42 mm (wall thickness is 3 mm, inner diameter is 36 mm), and closes the lower end of the zinc gas supply pipe 18 so that only the vertical wall has an equal interval of 120 ° with respect to the central axis C. The opening position (the center position of the opening) of three zinc gas supply ports 18a provided at 16 mm is set so that the length L3 from the mating surface to the upper lid 12 of the reactor 10 is 300 mm, and the reactor 10 to the bottom Quartz exhaust pipe 20 having inlet 20a is an outer diameter 56 mm (wall thickness is 2 mm, internal diameter 52 mm) was set on.

Further, three quartz inert gas supply pipes 14 and quartz silicon tetrachloride gas supply pipes 16 disposed therein are arranged at a distance of 85 mm from the central axis C at equal intervals of 120 degrees. Then, three rod members 24b of each peeling mechanism 24 were disposed at equal intervals of 120 ° at a distance of 85 mm from the central axis C with the three inert gas supply pipes 14 correspondingly interposed therebetween.

Here, each inert gas supply pipe 14 has an outer diameter set to 16 mm (thickness is 1 mm, inner diameter is 14 mm), and the opening position of the inert gas supply port 14a (reactor of the inert gas supply pipe 14). 10 is set so that the length L1 from the mating surface to the top lid 12 of the reactor 10 is 10 mm, and each silicon tetrachloride gas supply pipe 16 has an outer diameter of 9 mm (wall thickness). Is set to 1 mm and the inner diameter is 7 mm), and the silicon tetrachloride gas supply is provided by closing the lower end of the silicon tetrachloride gas supply pipe 16 so that only the vertical wall has a diameter of 4 mm and faces the inner wall of the inner pipe 26. The opening position of the mouth 16a (the center position of the opening) was set so that the length L2 from the mating surface to the upper lid 12 of the reactor 10 was 500 mm.

Further, for each peeling mechanism 24, the rod member 24b is made of quartz and is a columnar rod member extending in the vertical direction, and its outer diameter is set to 9 mm and length 1900 mm. As a metal, its natural length was set to 100 mm and its spring constant was set to 0.15 kg / mm, and the weight 24d was made of iron and its weight was set to 3 kg. As an initial state of the peeling mechanism 24, the load of the weight 24d was previously applied to the telescopic tube 24c, and the bar member 24b was positioned at the lowest position.

In the specific configuration described above, in order to shut off the inside of the reactor 10 from the outside, first, the valve 34 a of the valve device 34 is closed, and then, from the inert gas supply port 14 a of the inert gas supply pipe 14. Ar gas having a flow rate of 83 SLM, Ar gas having a flow rate of 1.00 SLM from the silicon tetrachloride gas supply port 16 a of the silicon tetrachloride gas supply pipe 16, and 0.84 SLM from the zinc gas supply port 18 a of the zinc gas supply pipe 18 Of Ar gas (Ar gas having a total flow rate of 2.67 SLM) was discharged into the reactor 10.

Next, in such a state where Ar gas is supplied to the inside of the reactor 10, the heater 22 is energized, and the vertical wall of the corresponding reactor 10 and the vertical length of the inner pipe 26 by the first heating unit 22a. The temperature of the wall and the region inside thereof is raised and maintained so that the temperature is 1200 ° C, and the vertical wall of the corresponding reactor 10, the vertical wall of the inner pipe 26, and the region inside the wall are kept at 1100 ° C by the second heating unit 22b. The temperature was raised and maintained so that the corresponding vertical wall of the reactor 10, the vertical wall of the inner tube 26, and the region inside thereof were heated to 1000 ° C. and maintained by the third heating unit 22c.

Next, the heater 22 is energized in this way, and the first heating unit 22a, the second heating unit 22b, and the third heating unit 22c are respectively connected to the vertical wall of the reactor 10, the vertical wall of the inner tube 26, and A mixed gas obtained by mixing zinc gas with a flow rate of 10.000 SLM in addition to Ar gas at a flow rate of 10.84 SLM from the zinc gas supply port 18 a of the zinc gas supply pipe 18 in a state where the inner region is heated and maintained. The inside of the reactor 10 was discharged. At the same time, while discharging Ar gas at a flow rate of 0.83 SLM from the inert gas supply port 14a of the inert gas supply pipe 14 into the reactor 10, the gas in the silicon tetrachloride gas supply pipe 16 is tetrachlorided from the Ar gas. Switching to silicon gas, silicon tetrachloride gas having a flow rate of 5.00 SLM was discharged into the reactor 10 from the silicon tetrachloride gas supply port 16a and allowed to react for 120 minutes.

Next, after reacting for 120 minutes in this way, the supply of silicon tetrachloride gas and zinc gas, which are raw materials for the reaction, was stopped while the heater 22 was kept energized. Thereafter, again, Ar gas at a flow rate of 200 SLM from the inert gas supply port 14 a of the inert gas supply pipe 14, Ar gas at a flow rate of 200 SLM from the silicon tetrachloride gas supply port 16 a of the silicon tetrachloride gas supply pipe 16, and zinc gas Ar gas at a flow rate of 200 SLM was discharged from the zinc gas supply port 18a of the supply pipe 18 into the reactor 10, and the inside of the reactor 10 was replaced with Ar gas for 5 minutes.

Next, after replacing with Ar gas in this way, when the weight 24d is unlocked by the actuator 24e and pulled up, the telescopic tube 24c extends about 20 mm, thereby moving the bar member 24b vertically upward by about 20 mm. Thereafter, the weight 24d is again pushed down by the actuator 24e and the load is applied to the telescopic tube 24c, the telescopic tube 24c is contracted by about 20 mm, and the bar member 24b is returned to a position vertically lowered by about 20 mm.

Then, after repeating the above series of steps of 120 minutes of reaction, 5 minutes of replacement with Ar gas, and up and down movement of the rod twice in total, the valve device 34 connected below the reactor 10 The valve 34a is opened, the deposit on the valve 34a is dropped in the silicon recovery tank 36, and the recovered substance in the silicon recovery tank 36 is confirmed. As a result, zinc and zinc chloride are present in addition to the acicular polycrystalline silicon. did.

Such acicular polycrystalline silicon is deposited on the valve 34a of the valve device 34 after silicon is deposited on the inner wall surface of the inner tube 26 in the reactor 10 and then peeled off by the vertical movement operation of the rod member 24b. It is thought that it was recovered. In addition, it is considered that zinc and zinc chloride are cooled and solidified by diffusion of raw material zinc gas and by-product zinc chloride gas into a region not heated by the heater 22 in the lower part of the reactor 10. The weight of the acicular polycrystalline silicon was measured and found to be 766 g. The reaction rate of silicon tetrachloride gas used for the reaction was 51%. Moreover, it was 489g when the weight of zinc and zinc chloride was measured.

Here, when the acicular polycrystalline silicon was observed with an optical microscope, a colorless transparent quartz piece as a material of the inner tube 26 was not recognized. This is because the rod member 24b of the peeling mechanism 24 is moved up and down to peel silicon deposited on the inner wall surface of the inner tube 26 of the reactor 10, thereby preventing the quartz pieces from being mixed into the recovered polycrystalline silicon. It is thought that it was made.

(Experimental example 2)
In Experimental Example 2, the silicon manufacturing apparatus 1 according to the present embodiment is the same as the silicon manufacturing apparatus 1 except that three plate members 24f as shown in FIGS. 5A and 5B are provided on each of the three rod members 24b. Polycrystalline silicon was produced in the process.

Specifically, each plate-like member 24f has an arc shape with a radius of 82 mm centered on the central axis C, and the center angle is set to be 60 °. The wall thickness is 2 mm, and the length in the vertical direction is 100 mm. Further, the installation positions of the three plate-like members 24f were set so that the upper ends of the plate-like members 24f were respectively positioned at 1075 mm, 1375 mm, and 1725 mm from the upper end of the bar member 24b. *

In a state where the vertical wall of the reactor 10, the vertical wall of the inner tube 26 and the region inside the reactor are heated and maintained, a mixed gas in which a zinc gas having a flow rate of 16.00 SLM is mixed in addition to Ar gas is mixed with 17.34 SLM. It was discharged into the reactor 10 from the zinc gas supply port 18a of the zinc gas supply pipe 18 at a flow rate. At the same time, while discharging Ar gas having a flow rate of 1.33 SLM from the inert gas supply port 14a of the inert gas supply pipe 14 into the reactor 10, the gas in the silicon tetrachloride gas supply pipe 16 is tetrachlorided from the Ar gas. Switching to silicon gas, silicon tetrachloride gas having a flow rate of 8.00 SLM was discharged into the reactor 10 from the silicon tetrachloride gas supply port 16a and allowed to react for 120 minutes.

Next, in the same manner as in Experimental Example 1, a silicon recovery step was performed by replacement with Ar gas for 5 minutes and a vertical movement operation of the rod. When a series of steps from the reaction for 120 minutes to the recovery step as described above was repeated twice in total, zinc and zinc chloride were present in the silicon recovery tank 36 in addition to acicular polycrystalline silicon.

When the weight of such acicular polycrystalline silicon was measured, it was 1082 g, and the reaction rate of silicon tetrachloride gas subjected to the reaction was 45%. Moreover, when the weight of zinc and zinc chloride was measured, it was 583g.

Here, when the acicular polycrystalline silicon was observed with an optical microscope, a colorless transparent quartz piece as a material of the inner tube 26 was not recognized.

(Experimental example 3)
In Experimental Example 3, in addition to providing three plate members 24f as shown in FIGS. 5A and 5B in each of the three rod members 24b in the silicon manufacturing apparatus 1 of the present embodiment, As shown in FIG. 4B, polycrystalline silicon was produced in the same manner as in Experimental Example 2, except that three plate members 28 were installed in the inner tube 26 so as not to interfere with each other.

Specifically, three plate-like members 28 were installed at equal intervals of 120 ° in the circumferential direction of the inner tube 26. Each plate-like member 28 was set to have a thickness of 3 mm, a length toward the central axis C of 44 mm, and a vertical length of 805 mm. In the inner pipe 26, the silicon tetrachloride gas supply pipe 16 and the plate-like member 28 are on a straight line parallel to the central axis C, and the plate-like member 28 exists vertically below the silicon tetrachloride gas supply pipe 16. It was arranged in the reactor 10 as described above.

In the above specific configuration, the same steps as in Experimental Example 2 were performed, and the reaction was performed with zinc and silicon tetrachloride for 120 minutes.

Next, in the same manner as in Experimental Example 1, a silicon recovery step was performed by replacement with Ar gas for 5 minutes and a vertical movement operation of the rod. When a series of steps from the reaction for 120 minutes to the recovery step was repeated twice in total, zinc and zinc chloride were present in the silicon recovery tank 36 in addition to acicular polycrystalline silicon.

When the weight of such acicular polycrystalline silicon was measured, it was 1240 g, and the reaction rate of the silicon tetrachloride gas subjected to the reaction was 52%. Moreover, when the weight of zinc and zinc chloride was measured, it was 694 g.

(Experimental example 4)
In Experimental Example 4, in addition to providing the three plate members 24f as shown in FIGS. 5A and 5B in each of the three rod members 24b in the silicon manufacturing apparatus 1 of the present embodiment, As shown in FIG. 4B, polycrystalline silicon was manufactured in the same manner as in Experimental Example 2 except that three plate members 28 in contact with each other at the center were installed in the inner tube 26.

Specifically, three plate-like members 28 were installed at equal intervals of 120 ° in the circumferential direction of the inner tube 26. Each plate-like member 28 was set to have a thickness of 3 mm, a length toward the central axis C of 94 mm, and a vertical length of 805 mm. Similar to Experimental Example 3, the inner tube 26 is configured such that the silicon tetrachloride gas supply pipe 16 and the plate member 28 are on a straight line parallel to the central axis C, and the plate member 28 supplies the silicon tetrachloride gas. It arrange | positioned in the reactor 10 so that it might exist below the pipe | tube 16 vertically.

When the weight of such acicular polycrystalline silicon was measured, it was 1294 g, and the reaction rate of the silicon tetrachloride gas subjected to the reaction was 54%. Moreover, it was 660 g when the weight of zinc and zinc chloride was measured.

(Comparative example)
In this comparative example, polycrystalline silicon was manufactured in the same manner as in the experimental example, except that a silicon manufacturing apparatus having a configuration in which the peeling mechanism 24 was replaced with a shock blow gas supply pipe in the silicon manufacturing apparatus 1 of the present embodiment was used. Here, each shock blow gas supply pipe is made of quartz, and is inserted into each insertion hole 12c of the upper lid 12 while being connected to a high-pressure inert gas supply source (not shown) and fixed to the reactor. Shock blow gas that penetrates into the interior of the reactor 10 and extends vertically downward along the inner wall surfaces of the reactor 10 and the inner tube 26, opens at the end inside the reactor 10 toward the vertically downward direction. Has a supply port.

Specifically, three shock blow gas supply pipes were arranged at an equal interval of 120 ° at a distance of 85 mm from the central axis C with the three inert gas supply pipes 14 correspondingly sandwiched therebetween. Each shock blow gas supply pipe has an outer diameter set to 9 mm (wall thickness is 1 mm, inner diameter is 7 mm), and the opening position of the shock blow gas supply port (the position of the end of the shock blow gas supply pipe in the reactor 10) ) Was set so that the length from the mating surface to the upper lid 12 of the reactor 10 was 600 mm.

In the above specific configuration, each step similar to the experimental example was performed, and after reacting with zinc and silicon tetrachloride for 120 minutes, Ar gas was substituted for 5 minutes. Then, Ar gas was discharged from the shock blow gas supply port of the shock blow gas supply pipe at a high pressure to perform shock blow. The shock blow conditions at this time are as follows: the pressure of Ar gas is 0.4 MPa, the time of one shock blow is set to 0.5 seconds, and the interval until the next shock blow is 3.0 seconds, for a total of 15 Shock blows were performed.

Then, after repeating the above-mentioned 120 minutes of reaction, 5 minutes of Ar gas replacement, and 15 shock blows of Ar gas for a total of 2 times in total, the valve device 34 connected below the reactor 10 The valve 34a is opened, the deposit on the valve 34a is dropped in the silicon recovery tank 36, and the recovered substance in the silicon recovery tank 36 is confirmed. As a result, zinc and zinc chloride are present in addition to the acicular polycrystalline silicon. did.

Such needle-shaped polycrystalline silicon is recovered from silicon deposited on the inner wall surface of the inner tube 26 in the reactor 10 and then separated by shock blow and deposited on the valve 34a of the valve device 34. Conceivable. In addition, it is considered that zinc and zinc chloride are cooled and solidified by diffusion of raw material zinc gas and by-product zinc chloride gas into a region not heated by the heater below the reactor 10. The weight of the acicular polycrystalline silicon was measured and found to be 781 g. The reaction rate of the silicon tetrachloride gas used for the reaction was 52%. Moreover, it was 499 g when the weight of zinc and zinc chloride was measured.

針 Here, when the acicular polycrystalline silicon was observed with an optical microscope, a very small amount of colorless and transparent quartz pieces were mixed. Further, as a result of visually observing the inner wall surface of the portion corresponding to the silicon precipitation region S of the inner tube 26, innumerable cracks were observed. This is because Ar gas having a low temperature is blown to the interface between the inner wall surface of the quartz inner tube 26 and silicon at the time of shock blow, and due to the difference in thermal expansion coefficient between these two types of materials, It is considered that stress was generated on the inner wall surface, and a part of the inner wall surface of the inner tube 26 was peeled off and dropped into the silicon recovered by dropping downward together with the silicon.

By comparing each of the above experimental examples with the comparative example, in each experimental example, mixing of quartz pieces into the recovered polycrystalline silicon as seen in the comparative example can be prevented, and the separation mechanism 24 can move freely. It can be said that the significance of providing the rod member 24b is confirmed.

In addition, by comparing the experimental example 1 and the experimental example 2, it was confirmed that the provision of the plate member 24f increases the amount of silicon recovered by providing the plate member 24f on the rod member 24b. It can be said. Further, by comparing the experimental example 2 with the experimental example 3 or the experimental example 4, by providing the plate-like member 28 in the inner tube 26, the silicon recovery amount is increased. It can be said that the effect of increasing the deposition rate was confirmed.

In the present invention, the type, arrangement, number, and the like of the members are not limited to the above-described embodiments, and the components depart from the gist of the invention, such as appropriately replacing the constituent elements with those having the same operational effects. Of course, it can be appropriately changed within the range not to be.

As described above, in the present invention, it is possible to produce polycrystalline silicon at a low cost and in a high yield, and continuously while suppressing mixing of materials of members having a surface on which silicon is deposited. In addition, it is possible to provide a silicon manufacturing apparatus and a silicon manufacturing method that are capable of recovering polycrystalline silicon efficiently and from a general-purpose universal character, such as silicon for solar cells. It is expected that it can be applied to a wide range of manufacturing equipment.

Claims

A reactor standing vertically,
A silicon tetrachloride gas supply pipe that communicates with the reactor and has a silicon tetrachloride gas supply port, and supplies silicon tetrachloride gas into the reactor from the silicon tetrachloride gas supply port;
A zinc gas supply port communicating with the reactor, and a zinc gas supply pipe for supplying zinc gas into the reaction vessel from the zinc gas supply port;
A heater for heating the reactor;
A peeling member that has a rod member that enters the reactor, and is movable in the vertical direction.
While supplying a silicon tetrachloride gas into the reactor from the silicon tetrachloride gas supply port while setting a temperature of a part of the reactor in the precipitation temperature range of silicon in the heater, the zinc gas supply Zinc gas is supplied into the reaction vessel from the mouth, silicon tetrachloride is reduced with zinc in the reactor, and the wall corresponding to the region set in the silicon deposition temperature range in the reactor After the silicon deposition region where silicon is deposited on the silicon deposition region, the peeling mechanism moves while applying the rod member to the silicon deposited on the silicon deposition region, thereby separating the silicon deposited on the silicon deposition region. Manufacturing equipment.
2. The silicon manufacturing apparatus according to claim 1, wherein the peeling mechanism further includes an expansion tube that is an elastic member through which the rod member is inserted to seal the inside, and a weight that can apply a load to the expansion tube.
3. The silicon manufacturing apparatus according to claim 1, wherein the bar member extends in the vertical direction and is movable while facing the silicon deposition region.
And an inner tube detachably inserted inside the reactor, wherein the silicon deposition region is an inner tube of the reactor in the reactor corresponding to a region set in the silicon deposition temperature range. The silicon manufacturing apparatus according to claim 1, wherein the silicon manufacturing apparatus is a wall surface.
Furthermore, the plate-shaped member connected with the inner wall face of the said inner tube is provided, The said silicon precipitation area | region contains the wall face of the said plate-like member corresponding to the said area | region set to the precipitation temperature range of the said silicon | silicone. Silicon manufacturing equipment as described in
A reactor standing vertically,
A silicon tetrachloride gas supply pipe that communicates with the reactor and has a silicon tetrachloride gas supply port, and supplies silicon tetrachloride gas into the reactor from the silicon tetrachloride gas supply port;
A zinc gas supply port communicating with the reactor, and a zinc gas supply pipe for supplying zinc gas into the reaction vessel from the zinc gas supply port;
A heater for heating the reactor;
A peeling mechanism having a bar member, the bar member being movable in the vertical direction;
Using a silicon manufacturing apparatus equipped with
While supplying a silicon tetrachloride gas into the reactor from the silicon tetrachloride gas supply port while setting a temperature of a part of the reactor in the precipitation temperature range of silicon in the heater, the zinc gas supply Zinc gas is supplied into the reaction vessel from the mouth, silicon tetrachloride is reduced with zinc in the reactor, and the wall corresponding to the region set in the silicon deposition temperature range in the reactor After the silicon deposition region where silicon is deposited on the silicon deposition region, the peeling mechanism moves while applying the rod member to the silicon deposited on the silicon deposition region, thereby separating the silicon deposited on the silicon deposition region. Production method.