JP2018065717A - Polycrystalline silicon reaction furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polycrystalline silicon reaction furnace that is capable of heating a silicon core rod with a heater in a short period of time and can produce a high-purity polycrystalline silicon.SOLUTION: A polycrystalline silicon reaction furnace 100 is provided which is configured to produce a polycrystalline silicon on surfaces of a plurality of silicon core rods 31 by electrically heating the silicon core rods 31 disposed within the furnace and reacting a raw material gas fed into the furnace. The furnace includes, at its center, a heater 4 capable of heating the silicon core rods 31, and includes the silicon core rods 31 at an outer peripheral side of the heater 4 in the furnace. The heater 4 includes heater core rods 40 formed of multiple-stage heater small rods 41, 42 combined along the vertical direction of the silicon core rods 31. The heater small rod 41, provided at the lower stage, is disposed on the outer peripheral side of the heater small rod 42, provided at the upper stage, in the furnace.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a polycrystalline silicon reactor used for producing polycrystalline silicon by the Siemens method.

  A Siemens method is known as a method for producing high-purity polycrystalline silicon used as a semiconductor material. The Siemens method is a manufacturing method in which a source gas composed of a mixed gas of chlorosilane and hydrogen is brought into contact with a heated silicon core rod, and polycrystalline silicon is deposited on the surface thereof by reaction of the source gas. As an apparatus for carrying out this manufacturing method, a polycrystalline silicon reactor in which a large number of silicon core rods are erected in a sealed reactor is used. In general, this silicon core rod is connected by a connecting member at the upper end portion, and is formed in a letter shape as a whole, and both lower end portions thereof are fixed to electrodes installed on the bottom of the reactor.

  Then, the silicon core rod is energized from the electrodes located at both ends thereof, and the entire silicon core rod is heated by the Joule heat to, for example, about 900 ° C. to 1200 ° C., which is the thermal decomposition temperature of the raw material gas. The raw material gas supplied into the furnace comes into contact with the surface of the silicon core rod thus heated and is thermally decomposed or hydrogen reduced, and polycrystalline silicon is deposited on the surface of the silicon core rod. As this reaction proceeds continuously, it grows into rod-shaped polycrystalline silicon.

  The silicon core rod is formed of high-purity polycrystalline silicon or single crystal silicon. However, high-purity silicon core rods have high resistance, and such silicon core rods cannot be energized at room temperature. For this reason, the specific resistance is lowered by heating the silicon core to a certain temperature in advance, and the silicon core is energized. In order to perform heating before such energization, for example, as disclosed in Patent Document 1, a long heater made of carbon is provided in the reaction furnace. As another method for heating the silicon core rod, Patent Document 2 and Patent Document 3 disclose a method in which a high melting point resistive material or a material made of silicon is used as the material of the heater. Furthermore, as a heating method before energization of the silicon core rod, in addition to a method of installing a heater in the reaction furnace, for example, Patent Document 4 discloses a method of supplying heat from the outside to the inside of the reaction furnace. Reduction of contamination from the heater during heating of the silicon core rod has been an issue.

JP 2009-73683 A Special table 2009-536914 JP 2013-193931 A JP 2001-278611 A JP 2014-101256 A

In the production of high-purity polycrystalline silicon, reduction of impurities is also required in the production process. In Patent Document 1, a carbon heater is used in the central part of the reaction furnace, and the silicon core rod is quickly heated. A method for improving the productivity of precipitated silicon by increasing the temperature has been performed.
In the methods disclosed in Patent Document 2 and Patent Document 3, carbon-derived contaminants can be reduced, but in Patent Document 2, contamination from a refractory metal remains as a problem. On the other hand, although a certain quality improvement effect is recognized even in a heater made of silicon, impurities such as phosphorus, arsenic, boron and the like are added in a very small amount in the manufacturing stage. Issues remain in improving quality.

  Patent Document 4 is a method in which a heater that becomes a contamination source during initial heating of the silicon core rod is not installed inside the reaction furnace, but the polycrystalline silicon reaction furnace itself needs to be modified, resulting in an increase in equipment costs and durability. There are problems with sex. In addition, this method can eliminate the influence of contamination from the heater that heats the silicon core rod, but the furnace wall is also likely to be heated at the same time, so there is a possibility of causing metal contamination. Remains a problem.

In Patent Document 5, a heater having an inverted U shape is installed in a polycrystalline silicon reactor (polycrystalline silicon manufacturing apparatus), and the horizontal arrangement of the heater can be easily changed, so that a silicon core rod (silicon To the silicon deposition, the optimal arrangement from the three viewpoints of the initial heating of the core rod), the influence on the silicon deposition on the silicon core rod, and the silicon deposition on the heater becomes easy. Although the effect of is recognized, there is no mention of silicon quality.
As described above, the initial heating method of the silicon core rod in the production of polycrystalline silicon has been studied from various aspects, but the problem has not been solved as a method for reducing the influence of impurities.

  The present invention has been made in view of such circumstances, and provides a polycrystalline silicon reactor that can heat a silicon core rod with a heater in a short time and can produce high-purity polycrystalline silicon. For the purpose.

  In a polycrystalline silicon reactor, cooling of a furnace wall, a base, a metal electrode, etc. is performed in order to avoid impurity contamination due to the influence of outgas from the furnace wall constituting the reactor. In general, in the case of a bell jar type reactor, the cooling refrigerant is also circulated through the bell jar furnace wall, but when circulated from the lower side to the upper side of the bell jar, the base side in the reactor, That is, the temperature on the lower side of the reactor tends to be lower than that on the upper side. In addition, the temperature on the furnace wall side of the reaction furnace tends to be lower than that in the central part. For this reason, the heater for heating the silicon core rod is more efficient in heating than the furnace wall side than the furnace wall side, and the silicon core rod on the lower side is more efficient than the upper side of the furnace. It is desirable to heat. Further, as a heater for heating the silicon core rod, a heater made of a carbon material is used because stable heating can be performed in a high temperature region. Since this carbon heater generally reduces contamination during use, impurities are removed in a high-temperature treatment in a chlorine atmosphere or the like before use, but it is difficult to reduce contamination from the heater. Cost. For this reason, it is desirable to use the heater in as short a time as possible.

  The present invention relates to a polycrystalline silicon reactor in which a plurality of silicon core rods provided in a furnace are energized and heated, and a raw material gas supplied into the furnace is reacted to generate polycrystalline silicon on the silicon core rod surface. The heater includes a heater capable of heating the silicon core rod in the center of the furnace, the silicon core rod is provided on the outer peripheral side of the furnace than the heater, and the heater extends in the vertical direction of the silicon core rod. A heater core rod formed by combining a plurality of stages of heater rods along the heater core rod, the lower heater side rod is more than the heater rod disposed on the upper stage side, It is arrange | positioned at the outer peripheral side in the said furnace.

  By combining a plurality of heater rods in this way, it becomes possible to arrange the heater rod on the lower side closer to the silicon core rod at the innermost peripheral position in the furnace, and the silicon core rod on the lower side of the reactor The upper side of the silicon core rod can be arranged farther from the silicon core rod than the lower heater small rod as compared with the lower side. Thereby, compared with the conventional elongate heater, while being able to heat a silicon | silicone core rod to the temperature which can supply with electricity in a short time, the grade of the contamination derived from a heater can be reduced.

  At this time, the heater disposed in the center of the furnace (the region from the center of the base to the inside of the silicon core at the innermost position) is gradually moved from the silicon core at a position close to the heater (the innermost position). The silicon core rod rises in temperature until the silicon core rod can be energized, and a predetermined voltage is applied to the electrode of the silicon core rod in advance, so that the silicon core rod generates resistance heat by its own energization. It becomes a state. Then, the radiant heat of the silicon core rod in the heat generating state heats the surrounding silicon core rod, so that the silicon core rod outside the reaction furnace is heated and energized to enter the resistance heat generation state. The energization of the heater can be cut after at least the silicon core rod near the heater is energized to generate a heat generation state. Since the heater is energized in a short time, the heater is not heated to an unnecessarily high temperature, damage to the heater can be prevented, and impurities derived from the heater are taken into the polycrystalline silicon. Can be suppressed.

In the polycrystalline silicon reactor according to the present invention, the cross-sectional area of the vertical surface with respect to the length direction of the lower heater wand is equal to the cross-sectional area of the vertical surface with respect to the length direction of the upper heater wand or It is good to form small.
In the polycrystalline silicon reactor according to the present invention, the resistivity of the lower heater rod may be equal to or higher than the resistivity of the upper heater rod.

By adjusting the cross-sectional area of the vertical plane with respect to the length direction of the heater rod of each stage constituting the heater and the resistivity as described above, the amount of heat generated by the lower heater rod is increased, and the upper stage side The amount of heat generated by the heater rod can be reduced. Therefore, heating can be performed more effectively in a short time from the lower side to the upper side of the silicon core rod.
In the polycrystalline silicon reactor according to the present invention, the heater for heating the silicon core rod is composed of a plurality of heater rods, and the upper heater rod is separated from the silicon core rod than the lower heater rod. (Distantly), the diameter increases due to silicon deposition on the silicon core, preventing the occurrence of contamination and energization troubles due to the upper part of the silicon core contacting the heater. In addition, when taking out the silicon rod after silicon deposition from the reactor, it is possible to reduce the risk of handling handling load and damage. In addition, the polycrystalline silicon reactor of the present invention has a structure of a heater rod in the heat treatment for reducing impurities derived from the heater before using the heater, thereby performing heat treatment of the long heater. In comparison, since a large heat treatment facility is not required and the treatment can be performed with a relatively small treatment facility, there is a great merit in terms of initial investment and running cost of the facility.

In the polycrystalline silicon reactor according to the present invention, a plurality of the heaters may be arranged at a central portion in the furnace.
By adopting a configuration in which a plurality of heaters are arranged, the amount of heat generated by the entire heater per unit time increases, so that the silicon core rod can be heated in a shorter time.

  According to the present invention, a silicon core rod can be heated in a short time in preference to the upper side of the silicon core rod in a shorter time than the upper side by a heater composed of a plurality of stages of silicon rods. Time can be shortened, the impurities derived from the heater can be prevented from being taken into the polycrystalline silicon, and high-purity polycrystalline silicon can be produced.

It is a schematic block diagram of the polycrystalline silicon reactor of embodiment of this invention. FIG. 2 is a perspective view of a heater and a silicon core rod at the innermost peripheral position in the vicinity of the center of the base of the polycrystalline silicon reactor shown in FIG. 1. FIG. 2 is a main part view near a connection member of a heater of the polycrystalline silicon reactor shown in FIG. 1. It is a principal part figure of the connection member vicinity of the heater core rod of the polycrystalline silicon reactor shown in FIG. It is a principal part figure of the connection member vicinity of the heater core rod of the polycrystalline silicon reactor shown in FIG. It is a schematic diagram of the heater in other embodiment.

Hereinafter, an embodiment of a polycrystalline silicon reactor according to the present invention will be described.
FIG. 1 is an overall view schematically showing a polycrystalline silicon reactor to which the present invention is applied. The polycrystalline silicon reactor 100 includes a base 1 that constitutes the bottom of the furnace, and a bell-shaped bell jar 2 that is detachably mounted on the base 1, and a plurality of silicon cores provided in the furnace. The rod 31 is energized and heated to cause the source gas supplied into the furnace to react to produce polycrystalline silicon on the surface of the silicon core 31. Further, in the polycrystalline silicon reactor 100, a heater 4 for heating to energize the silicon core 31 is provided at the center of the base 1 (the silicon core 31 at the innermost position from the center of the base 1. The silicon core rod 31 is disposed on the outer peripheral side of the base 1 (inside the furnace) rather than the heater 4.

  The upper surface 10 of the base 1 is formed in a substantially flat horizontal plane. On the upper surface 10, as shown in FIG. 1 or FIG. 2, a silicon core rod 31 serving as a seed rod for the generated polycrystalline silicon is provided. A connecting member 5A to be attached, a connecting member 5B to which the heater 4 is attached, a gas supply port for supplying a raw material gas containing chlorosilane gas and hydrogen gas into the furnace, and a gas after reaction outside the furnace A plurality of gas discharge ports for discharging are provided.

  The gas supply ports of the source gas are dispersed almost at all intervals except for the central portion of the upper surface 10 of the base 1 so that the source gas can be uniformly supplied to the silicon core rods 31 at appropriate intervals. There are multiple installations. Moreover, the gas supply port is installed in the position away from the connection member 5B to which the heater 4 of the base center part in a furnace is attached so that the heating of the heater 4 may not be affected. Although not shown, these gas supply ports are connected to a source gas supply source outside the furnace. In addition, a plurality of gas discharge ports are installed at appropriate intervals, and although not shown, they are connected to an external exhaust gas treatment system.

As described above, the upper surface 10 of the base 1 of the polycrystalline silicon reactor 100 is provided with a plurality of connecting members 5A for holding and energizing the silicon core rod 31, and these connecting members 5A are A plurality of silicon core rods 31 are connected to a power cable (not shown) through which current flows.
Further, a connecting member 5B for holding the heater 4 for heating the silicon core 31 is provided on the upper surface 10 of the base 1 of the polycrystalline silicon reactor 100. An electric current flows through the heater 4 through the heater 4.

  As shown in FIG. 2, the connecting member 5 </ b> A to which the silicon core rod 31 is attached is attached to an electrode (not shown) formed on the base 1 and connects between the electrode and the silicon core rod 31. Part 51 and a holding part 52 which is attached to the upper part of the holder part 51 and holds the lower end part of the silicon core 31.

  2 and 3, the connecting member 5B to which the heater 4 is attached is formed on the base 1 and is insulated from the base 1, and the heater 4 is attached to the electrode 55. The electrode 55 and the heater 4 are connected to each other via the holding unit 56. The holding portion 56 is made of a conductive material formed in a substantially cylindrical shape. A holding hole into which the heater 4 is inserted is formed in the upper portion, and a female screw hole into which the electrode 55 can be screwed is formed in the lower portion. Has been.

The heater 4 is a carbon-based heater, and is erected on the upper surface 10 of the base 1 by being held by the connecting member 5B disposed in the center of the furnace as described above. In addition, the polycrystalline silicon reactor 100 of the present embodiment is provided with a pair of heaters 4 formed in an inverted U shape by connecting a heater core rod 40 with a connecting member 44 at the upper end thereof. ing. Each heater 4 (heater core rod 40) is set to a height corresponding to the entire length of the silicon core rod 31 so that radiant heat is transmitted to the entire length of the adjacent silicon core rod 31 in the vicinity.
The heater core rod 40 constituting the heater 4 is configured by combining a plurality of stages of heater rods along the vertical direction of each silicon core rod 31, and in the polycrystalline silicon reactor 100 of the present embodiment. As shown in FIG. 2, the heater core rod 40 is composed of a two-stage heater rod 41, 42, which is a combination of a lower heater rod 41 and an upper heater rod 42. . The lower heater bar 41 arranged in the lower stage is arranged closer to the outer peripheral side of the central portion of the furnace (base 1) than the heater small bar 42 arranged in the upper stage, and the silicon core 31 It is provided in the position near.

  Specifically, as shown in FIG. 2, the lower heater small bar 41 is held by the connecting member 5B. For example, as shown in FIG. 3, the lower end of the lower heater small bar 41 is inserted into the holding portion 56 of the connecting member 5 </ b> B, and the lower heater small bar 41 is inserted from the outer surface side of the holding portion 56. It is fixed by being pressed by a fixing screw 58 and extends upward from the base 1. As shown in FIG. 4, the lower end of the upper heater small bar 42 is attached to the upper end of the lower heater small bar 41 via a connecting member 43, and the lower heater small bar 41 is attached. The axis 41 of the heater and the axis of the heater small bar 42 on the upper stage side are arranged so as to be shifted in the horizontal direction.

  As shown in FIG. 4, the connection member 43 is provided with two insertion holes 43 a into which the upper end of the lower heater rod 41 and the lower end of the upper heater rod 42 can be inserted. The heater rods 41 and 42 are fixed together with the connection member 43 so that the nut 46 can be screwed together.

  Further, as described above, the heater 4 is formed in an inverted U shape by connecting the upper heater side small rods 42 of the two heater core rods 40 by the connecting member 44. As shown in FIG. 5, the connecting member 44 is provided with two insertion holes 44 a through which the upper end portions of the heater rods 42 on the upper side of the heater core rods 40 can be inserted. Are fixed together with the connecting member 44 so as to be screwable.

  The heater rods 41 and 42 and the connecting member 43, the nut 46, the connecting member 44, and the nut 47 constituting the heater 4 are made of carbon, and are perpendicular to the length direction of the heater rods 41 and 42. The cross-sectional areas are substantially the same size.

  In the heater 4 configured as described above, the upper heater small bar 42 is disposed at a position farther from the silicon core 31 than the lower heater small bar 41 on the upper side of the silicon core 31. Thereby, the lower side of the silicon core rod 31 located on the lower side of the polycrystalline silicon reactor 100 is heated by the lower heater side rod 41 arranged closer to the upper side than the upper side, The lower side of the silicon core rod 31 can be heated in a shorter time than the upper side.

  The silicon core rod 31 is held by a connecting member 5A disposed around the heater 4, and the lower end portion of each silicon core rod 31 is fixed by being inserted into the holding portion 52 of the connecting member 5A. As shown in FIG. 1, the base 1 extends upward. A connecting member 34 having a cylindrical through hole formed at both ends formed of silicon is attached to the upper end portion of each silicon core rod 31 to constitute a seed assembly having a generally U-shape.

  In addition, each seed assembly is arranged, for example, approximately concentrically from the center of the base 1. However, not all of the seed assemblies are necessarily concentric, and the silicon core rods 31 of some seed assemblies are radiused. It is good also as a structure containing what was arranged side by side in the direction.

  In the polycrystalline silicon reactor 100, the bell jar 2 and the base 1 are cooled in order to suppress the temperature rise of the furnace itself.

  In the polycrystalline silicon reactor 100 configured as described above, by applying a predetermined voltage to each connecting member 5B connected to the heater 4, the heater 4 can generate heat by electric resistance. Accordingly, the heater rod 41 on the lower stage side of the heater 4 is disposed closer to the silicon core rod 31 at the innermost peripheral position than the heater rod 42 on the upper stage side. Heating is promoted by the lower heater bar 41 arranged in the close position. As a result, the heating of the lower side as well as the upper side of the silicon core rod 31 proceeds, and the silicon core rod 31 can be heated over the entire length in a short time, and the resistance value of the silicon core rod 31 decreases accordingly. At this time, by applying a certain voltage to the connecting member 5A of the silicon core 31 as well, the silicon core 31 can be energized in a short time.

When the silicon core rod 31 at the innermost circumferential position disposed near the heater 4 is heated to a state where it can be energized and the temperature rises, the silicon core rod 31 is energized to enter a resistance heating state. The radiant heat is transmitted to adjacent silicon core rods 31 and heated. The heat transfer phenomenon is gradually propagated in the radial direction of the polycrystalline silicon reactor 100 and the like, and finally, all the silicon core rods 31 in the furnace are energized to be in a heat generating state. When these silicon core rods 31 are heated to the thermal decomposition temperature or hydrogen reduction temperature of the source gas, the source gas introduced from the gas supply port reacts on the surface of the silicon core rod 31 to produce polycrystalline silicon. Is generated.
The energization of the heater 4 can be cut after at least the innermost silicon core 31 near the heater 4 is energized and the silicon core 31 is energized.

  As described above, in the polycrystalline silicon reactor 100 of the present embodiment, the heating of the lower side as well as the heating of the upper side of the silicon core 31 proceeds, and as a result, it can be heated in a short time over the entire length of the silicon core 31. Contamination due to impurities from the heater 4 can be suppressed, and high-purity polycrystalline silicon can be generated.

In the polycrystalline silicon reactor 100 of the above embodiment, the cross-sectional areas of the vertical surfaces with respect to the length direction of the heater rods 41 and 42 of each stage constituting the heater 4 are formed with substantially the same (equivalent) size. However, the cross-sectional area of the vertical surface with respect to the length direction of the lower heater side rod 41 may be formed smaller than the cross-sectional area of the vertical surface with respect to the length direction of the upper heater side rod 42. Alternatively, the resistivity of the lower heater small bar 41 may be equal to or higher than that of the upper heater small bar 42.
As described above, the cross-sectional area of the vertical plane with respect to the length direction of the heater rods 41 and 42 of each stage constituting the heater 4 and the resistivity are adjusted as described above, so that the heater rods 41 on the lower stage side generate heat. By making the amount larger than the amount of heat generated by the upper heater small rod 42, the silicon core rod 31 located on the lower side of the reactor having a relatively low temperature can be heated in a short time.

In the present embodiment, one set of heaters 4 is provided, but a plurality of heaters may be arranged such that the number of sets of heaters 4 is two or three. By adopting a configuration in which the number of sets of heaters 4 is increased, the amount of heat generated by the entire heater per unit time increases, so that the silicon core rod can be heated in a shorter time.
In addition, when arrange | positioning a some heater in the center part in a furnace, it is desirable to arrange | position in the equal position with respect to the position of each silicon | silicone core rod which adjoins a heater.

  Moreover, although illustration is abbreviate | omitted, when arrange | positioning a some heater in a furnace, it is desirable that several sets of heaters are mutually connected in the state which opened the fixed distance using the insulating member. Even if the heaters sway due to the momentum of the gas flow at the time of supplying the raw material gas to the reaction furnace by keeping a plurality of heaters connected to each other with a certain distance between the heaters, or Contact between the heater and the silicon core can be prevented. In addition, by keeping a certain distance between the heater and the silicon core rod, it is possible to prevent damage to the heater and the silicon core rod, such as energization troubles and breakage, so that the silicon core rod is heated stably. Can do. In this case, for example, a through hole may be provided in the connecting member 44 of each heater so that an insulating member for preventing contact between the heaters can be attached.

Further, in the polycrystalline silicon reactor 100 of the above embodiment, the heater core rod 40 is configured in two stages by the lower heater small bar 41 and the upper heater small bar 42. You may comprise combining the heater rod of a step.
For example, as shown in FIG. 6, when the heater core rod 40 </ b> S having the three-stage (lowermost, middle, uppermost) heater rods 75 to 77 is configured, the heater rod 75 arranged at the lowermost row. However, it is arranged on the outer peripheral side in the furnace with respect to the middle heater rod 76 and the uppermost heater rod 77 arranged on the upper stage side, and further the middle heater rod 76 is arranged on the uppermost heater rod. It is arrange | positioned rather than 77 at the outer peripheral side in a furnace.

  Further, in the polycrystalline silicon reactor 100 of the above embodiment, the connecting member 5B to which the heater 4 is attached holds the lower end portion of the heater 4 to the holding portion 56 attached to the electrode of the base 1, and the fixing screw 58. However, the fixing means of the heater 4 is not limited to this. Although illustration is omitted, for example, by forming a holding hole capable of holding the lower end portion of the heater 4 (heater rod 41) in the holding portion 56, the heater 4 is screwed into the holding hole of the holding portion 56. It is good also as a structure to hold | maintain.

  Further, in the polycrystalline silicon reactor 100 of the above embodiment, as shown in FIG. 4, the connecting member 43 that connects between the lower heater small bar 41 and the upper heater small bar 42 is provided with a nut 46. The connecting member 43 is fixed between the proximal end side nut 46 and the distal end side nut 46 by tightening, but the fixing means of the connecting member 43 and the heater rods 41 and 42 is limited to this. Not. Although illustration is omitted, the connecting member 43 and the heater rod are pressed by pressing the side surfaces of the heater rods 41 and 42 against the inner peripheral surface of the insertion hole 43a from the side surface of the connecting member 43 using, for example, a fixing screw. The state where 41 and 42 are contacted may be maintained and fixed.

  In addition, although the cross section of the front-end | tip part of the upper end part of the lower heater side small rod 41 and the lower end part of the upper stage heater small bar 42 may be circular or a square shape, the insertion hole 43a of the connection member 43 is the shape of a front-end | tip part. Are formed in a circular shape or a square shape (for example, a square hole), and are firmly fixed. Note that two or more fixing screws may be used, and the distal side surface portions of the heater small bars 41 and 42 may be pressed and fixed from different side surfaces of the connecting member 43 with the fixing screws.

  Further, in the polycrystalline silicon reactor 100 of the above embodiment, as shown in FIG. 5, the coupling member 44 that connects the heater core rods 40 is tightened with a nut 47, thereby Although the connecting member 44 is sandwiched and fixed between the nuts 47 on the distal end side, the fixing means between the connecting member 44 and the heater core 40 is not limited to this. Although illustration is omitted, for example, by using a fixing screw, the side surface of the heater small rod 42 on the upper side of the side surface of the connection member 44 is pressed against the inner peripheral surface of the insertion hole 44a of the connection member 44, thereby The upper heater side small rod 42 may be kept in contact with and fixed.

  In this case, the tip of the heater small rod 42 on the upper stage side is formed in a circular shape or a square shape (for example, a quadrangle) that is smaller than the middle abdomen, and the insertion hole 44 a of the connecting member 44 is formed in the heater small rod 42. It is formed in a circular shape or a square shape (for example, a square hole) according to the shape of the tip, and is firmly fixed. Note that two or more fixing screws may be used, and the tip side surface portion of the heater small bar 42 may be pressed and fixed from different side surfaces of the connecting member 44 with the fixing screws.

  Although the polycrystalline silicon reactor according to the embodiment of the present invention has been described above, the present invention is not limited to this and can be appropriately changed without departing from the technical idea of the present invention.

1 base 2 bell jar 4 heater 5A connection member (connection member to which a silicon core rod is attached)
5B Connection member (connection member to which the heater is attached)
10 Upper surface 31 Silicon core rod 34 Connecting member 40, 40S Heater core rod 41 Lower heater rod 42 Upper heater rod 43 Connecting member 44 Connecting member 51 Holder portion 52, 56 Holding portion 55 Electrode 58 Fixing screw 75, 76,77 Heater rod 100 Polycrystalline silicon reactor

Claims (4)

A polycrystalline silicon reaction furnace in which a plurality of silicon core rods provided in the furnace are energized and heated, the raw material gas supplied into the furnace is reacted, and polycrystalline silicon is generated on the silicon core rod surface,
A heater capable of heating the silicon core rod in the center of the furnace,
The silicon core rod is provided on the outer peripheral side in the furnace than the heater,
The heater has a heater core formed by combining a plurality of heater small bars along the vertical direction of the silicon core,
In the heater core rod, the lower heater side rod is arranged on the outer peripheral side in the furnace with respect to the heater rod arranged on the upper side.   The cross-sectional area of the vertical surface with respect to the length direction of the lower heater bar is formed to be equal to or smaller than the cross-sectional area of the vertical surface with respect to the length direction of the upper heater rod. The polycrystalline silicon reactor according to claim 1.   The polycrystalline silicon reactor according to claim 1, wherein the resistivity of the lower heater rod is equal to or higher than the resistivity of the upper heater rod.   The polycrystalline silicon reactor according to any one of claims 1 to 3, wherein a plurality of the heaters are arranged in a central portion of the furnace.

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