JP5012385B2 - Method for producing polycrystalline silicon rod - Google Patents

Description

  The present invention relates to a method for manufacturing a polycrystalline silicon rod.

There is a Siemens method as a method for producing high-purity polycrystalline silicon as a semiconductor material. The Siemens method is a manufacturing method in which a raw material gas composed of a mixed gas of chlorosilane and hydrogen is brought into contact with a heated silicon core rod, and polycrystalline silicon generated by thermal decomposition of the raw material gas is deposited on the surface thereof, and a sealed reaction A polycrystalline silicon reactor in which a large number of silicon core rods are installed in the furnace is used. Generally, a silicon core rod is formed in a columnar shape, and its tip is connected to the tip of another adjacent silicon core rod by a connecting member. And the base end of the silicon | silicone core rod is being fixed to the electrode installed in the furnace bottom of the reaction furnace. During operation, the entire silicon core rod is energized from the electrodes at both ends, and the entire silicon core rod is heated to the thermal decomposition temperature of the raw material gas by the Joule heat (see, for example, Patent Document 1).
Japanese Patent No. 3881647

  However, the conventional method for manufacturing a polycrystalline silicon rod has the following problems. That is, in the above conventional method for manufacturing a polycrystalline silicon rod, a pair of silicon core rods are connected to each other by a connecting member, and the silicon core rod and the connecting member are electrically connected to each other. It is desired to make the heating state uniform.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a method for manufacturing a polycrystalline silicon rod in which the conductive state between the silicon core rod and the connecting member is improved.

  The present invention employs the following configuration in order to solve the above problems. That is, in the method for producing a polycrystalline silicon rod according to the present invention, the tips of at least a pair of silicon core rods erected on the bottom of the reactor are inserted into a pair of insertion ports formed in the connecting member. A method of manufacturing a polycrystalline silicon rod that is connected and grows polycrystalline silicon on a peripheral surface of the silicon core rod, the step of standing each of the pair of silicon core rods on the bottom, Connecting the tip of each of the pair of silicon core rods with the connecting member in which the distance between the pair of insertion openings is shorter than the distance between the tips of the pair of silicon core rods standing upright.

According to this invention, when the pair of silicon core rods are connected by the connecting member, the tips of the pair of silicon core rods and the inner peripheral surface of the insertion port can be brought into contact with each other more reliably. Therefore, the conduction state of the pair of silicon core rods is improved, and the pair of silicon core rods can be favorably heated during energization heating. That is, when connecting the tip of each of the pair of silicon core rods with the connecting member, the interval between the pair of insertion holes is shorter than the distance between the tips of each of the pair of silicon core rods standing upright. It connects with a connection member in the state which made the front end approach. At this time, since the pair of silicon core rods are connected in a bent state, the connecting member is pulled in the separating direction of the pair of silicon core rods. Thereby, the outer peripheral surface on the side where the pair of silicon core rods are separated from each other at the distal end portion and the inner peripheral surface on the side where the pair of silicon core rods are separated from each other in the insertion port are in good contact. Therefore, the silicon core rod and the connecting member are in good contact.
Further, when the pair of silicon core rods pulls the connecting member in the separating direction, a frictional force is generated between the outer peripheral surface of the tip portion of the silicon core rod and the inner peripheral surface of the insertion port. For this reason, when the reaction gas is introduced into the reaction furnace and an air flow is generated upward from the bottom, the connecting member is unlikely to come off the silicon core rod.

In the method for producing a polycrystalline silicon rod, it is preferable that the tip of the tip portion protrudes from the connecting member.
In this invention, when the reaction gas is introduced into the reaction furnace and an air flow is generated upward from the bottom, the connecting member is less likely to come off the silicon core rod.

  According to the method for manufacturing a polycrystalline silicon rod of the present invention, since the conduction state is improved by more reliably bringing the tip of each of the pair of silicon core rods into contact with the inner peripheral surface of the insertion opening, The silicon core rod can be heated well. In addition, when the reactive gas is introduced and an upward air flow is generated from the bottom due to the frictional force generated between the outer peripheral surface of the tip of the silicon core rod and the inner peripheral surface of the insertion port, the connecting member becomes silicon. It becomes difficult to come off the core rod.

Hereinafter, an embodiment of a method for producing a polycrystalline silicon rod according to the present invention will be described with reference to the drawings. In each drawing used in the following description, the scale is appropriately changed to make each member a recognizable size.
First, a polycrystalline silicon reactor (hereinafter abbreviated as a reactor) used in the method for producing a polycrystalline silicon rod in the present embodiment will be described.

As shown in FIG. 1, the reaction furnace 1 includes a furnace base (bottom part) 11 and a bell jar 12 having a bell shape and covering the furnace base 11.
In the furnace 11, an electrode 14 that holds each of a plurality of pairs of silicon cores 13, an introduction port 15 that introduces a raw material gas into the reaction furnace 1, and an exhaust that discharges the reacted gas to the outside of the reaction furnace 1. A plurality of outlets 16 are provided.

As shown in FIGS. 1 and 2, the silicon core rod 13 is made of polycrystalline silicon, and has a core rod main body 13A and a tip portion 13B integrally formed at the tip of the core rod main body 13A. The core rod body 13A has a substantially quadrangular prism shape with one side of about several centimeters, for example. The tip portion 13B is a cylindrical convex portion that is formed integrally with the core rod body 13A and protrudes from the tip of the core rod body 13A, and is thinner than the core rod body 13A. In the silicon core rod 13, the base end of the core rod body 13 </ b> A is held and fixed to the electrode 14.
The silicon core 13 is connected to another adjacent silicon core 13 by a connecting member 17.

As shown in FIGS. 1 and 2, the connecting member 17 has a rectangular plate shape in plan view, and is formed of polycrystalline silicon like the silicon core rod 13. The connecting member 17 is formed with an insertion port 17a which is a pair of through holes. The insertion port 17a is formed by drilling the connecting member 17 using, for example, a drill. Further, the distal end portion 13 </ b> B of the silicon core rod 13 is inserted through the insertion port 17 a of the connecting member 17. Here, the center interval between the pair of insertion openings 17 a is substantially equal to the center interval at the base end of the pair of silicon core rods 13 connected by the connecting member 17.
Further, the distal end portion 13 </ b> B protrudes from the connecting member 17. Here, the connecting member 17 is pulled by the pair of silicon core rods 13 in the separating direction of the pair of silicon core rods 13.
Further, a cooling means (not shown) such as a water cooling jacket for preventing thermal damage is provided on the outer periphery of the bell jar 12 shown in FIG.

Next, a method for manufacturing a polycrystalline silicon rod using the reaction furnace 1 having the above configuration will be described.
First, the silicon core rod 13 is held by the electrode 14 and is erected from the furnace table 11. Here, as shown in FIG. 3, the pair of silicon core rods 13 connected by the connecting member 17 are held and fixed so as to be inclined so that the respective central axes are separated from the proximal end toward the distal end. At this time, the distance between the tips of the pair of silicon core rods 13 is wider than the distance between the pair of insertion ports 17 a formed in the connecting member 17.

  Then, a pair of adjacent silicon core rods 13 are connected by the connecting member 17. Here, the tip ends of the silicon core rods 13 are respectively inserted into the pair of insertion openings 17a in a state where the tip ends of the silicon core rods 13 are bent while being bent. At this time, since the pair of silicon core rods 13 are coupled by the coupling member 17 in a bent state, the coupling member 17 is pulled in the separating direction of the pair of silicon core rods 13 as shown in FIG. Thereby, the outer peripheral surface on the side where the silicon core rod 13 is separated from the tip portion 13B of each of the pair of silicon core rods 13 and the inner peripheral surface on the side where the silicon core rod 13 is separated in the insertion port 17a of the connecting member 17 are formed. Make sufficient contact.

In this state, current is passed through the electrode 14 to energize the silicon core rod 13 to generate Joule heat, and the silicon core rod 13 is heated to 1100 ° C. Then, a raw material gas which is a mixed gas of trichlorosilane (TCS: SiHCl ₃ ) having a purity of 11N (99.99999999999%) and hydrogen is introduced from the introduction port 15. At this time, since the contact state between the pair of silicon core rods 13 and the connecting member 17 is improved as described above, the pair of silicon core rods 13 are heated favorably.

The introduced source gas is thermally decomposed by contacting the heated silicon core rod 13 and the connecting member 17, and polycrystalline silicon is deposited on the surfaces of the silicon core rod 13 and the connecting member 17, thereby forming a polycrystalline silicon layer. After forming, it gradually grows to become a polycrystalline silicon rod with a diameter of several tens of centimeters. At this time, since the tip 13B of each of the pair of silicon core rods 13 is inserted through the insertion port 17a of the connecting member 17, the connecting member 17 remains in the pair of silicon even if the supplied reaction gas blows against the connecting member 17. It becomes difficult to come off from the core rod 13.
The gas after the reaction is exhausted to the outside from the discharge port 16. A polycrystalline silicon rod is manufactured as described above. From the thus produced polycrystalline silicon rod, a single crystal silicon ingot is produced by a CZ (Czochralski) method in which the rod is melted and pulled up in a crucible.

According to such a method for manufacturing a polycrystalline silicon rod, since the contact state between the pair of silicon core rods 13 and the connecting member 17 is improved, the pair of silicon core rods 13 can be heated satisfactorily. Thereby, a good quality polycrystalline silicon layer can be grown on the peripheral surface of the silicon core rod 13.
In addition, a frictional force is generated between the outer peripheral surface of each distal end portion of the pair of silicon core rods 13 and the inner peripheral surface of each of the pair of insertion ports 17a, and the distal end portion 13B is inserted through the insertion port 17a. Even if the reactive gas blows against the connecting member 17, the connecting member 17 does not come off from the pair of silicon core rods 13.

In addition, this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
For example, the core rod body has a quadrangular column shape, but may have another column shape such as a columnar shape. Similarly, the tip portion has a columnar shape, but may have another columnar shape as long as it is thinner than the core rod body.
Moreover, the silicon | silicone core rod should just be provided at least 1 opposed.
Each of the pair of silicon core rods connected by the connecting member is erected so as to be separated from each other as it goes from the proximal end to the distal end, but the distal ends are closer to each other than when standing upright. What is necessary is just to be connected by a connection member in the bent state, and may stand up so that a mutual center axis may become parallel.
Furthermore, the distance between the centers of the pair of insertion openings formed in the connecting member may be shorter than the distance between the tips of the pair of silicon core rods when they are erected.
Moreover, although the front-end | tip part has protruded from the connection member, a pair of silicon | silicone core rods should just be connected by inserting the front-end | tip part of a silicon | silicone core rod in an insertion port, and a pair of silicon | silicone cores with the reaction gas supplied If the connecting member does not come off the rod, it does not have to be projected.

  According to this invention, industrial applicability is recognized regarding the manufacturing method of the polycrystal silicon rod which made favorable the conduction | electrical_connection state of a silicon | silicone core rod and a connection member.

1 is a partially cutaway perspective view of a polycrystalline silicon reactor in an embodiment of the present invention. It is sectional drawing which shows the connection state of the silicon | silicone core rod by a connection member. It is sectional drawing which shows the standing state of the silicon | silicone core rod by a connection member.

Explanation of symbols

1 reactor (polycrystalline silicon reactor)
11 Furnace (bottom)
13 Silicon core rod 17 Connecting member 17a Insertion slot

Claims (2)

Inserting the tips of at least a pair of silicon cores erected at the bottom of the reactor into each of a pair of insertion ports formed in the connecting member, and connecting each other,
A method for producing a polycrystalline silicon rod for growing polycrystalline silicon on a peripheral surface of the silicon core rod,
Erecting each of the pair of silicon core rods on the bottom,
Connecting the tip ends of the pair of standing silicon core rods with the connecting member in which the distance between the pair of insertion ports is shorter than the distance between the tip ends of the pair of silicon core rods standing upright. A method for producing a polycrystalline silicon rod.   The method for producing a polycrystalline silicon rod according to claim 1, wherein tips of the pair of silicon core rods are protruded from the connecting member.

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