JPH038791A - Silicon single crystal manufacturing method and manufacturing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method and apparatus for pulling silicon single crystals by the Czochralski method (hereinafter referred to as the CZ method).

[Prior Art] A method of pulling a silicon single crystal using the Czochralski method while continuously supplying a silicon raw material is old and well known. FIG. 4 is a diagram showing a conventional silicon single crystal pulling apparatus. The advantage of this equipment is that the silicon single crystal 1 pulled from the silicon single crystal pulling section A
Since the amount of granular silicon raw material 12 commensurate with 1 is continuously supplied to the raw material supply section B, the amount of silicon melt 14 in the quartz crucible 13 can always be kept constant. .

As a result, the oxygen concentration in the longitudinal direction of the pulled silicon single crystal 11 can be kept the same at any position. Also, regarding the concentration of the dopant in the silicon single crystal 11, an amount corresponding to the amount of dopant taken into the silicon single crystal 11 that has been pulled is set in the silicon melt 14.
By continuously adding dopant to the silicon single crystal 11, the concentration of the dopant in the longitudinal direction of the silicon single crystal 11 can be kept constant, and a silicon single crystal of high quality and high yield can be manufactured.

[Problems to be Solved by the Invention] In the conventional CZ method, a raw material supply pipe 15 is disposed to continuously supply the granular silicon raw material 12 to the raw material supply section B, but the granular silicon raw material 12 In order to reliably supply the raw material supply part B to the raw material supply part B, it is necessary to bring the outlet of the raw material supply pipe 15 close to the liquid level of the silicon melt 14 in the raw material supply part B between the quartz pipe 13 and the partition member 16. .

Note that small holes 18 are arranged in the lower part of the partition member 16 to allow the silicon melt to flow.

However, when silicon single crystals were manufactured using the raw material supply pipe 15, the following problems occurred.

The vicinity of the outlet of the raw material supply pipe 15 is at a high temperature because the heater 17 is close to it. Silicon melting point (for example, 1420
The granular silicon raw material 1 is passed through the raw material supply pipe 15 at such a high temperature that the temperature exceeds °C.
2, the silicon raw material 12 passes through the raw material supply pipe 15
The material is gradually deposited on the inner wall of the raw material supply pipe 15.
It gets clogged. - Once it is clogged, it becomes impossible to continuously supply the silicon raw material 12 from now on, making it impossible to manufacture high-quality silicon single crystals.

This invention was made in view of such circumstances, and
The present invention aims to provide a method and device for preventing clogging of raw material supply pipes in the CZ method.

[Means for Solving the Problems] The silicon single crystal manufacturing method and apparatus of the present invention provide a raw material supply system for supplying a single crystal growth section of a silicon single crystal inside a crucible containing molten silicon and a silicon raw material outside. The silicon raw material is continuously supplied to the raw material supplying section and while melting, the molten silicon is gently transferred to the single crystal growth section through the small holes of the partitioning member, and In a method for producing a silicon single crystal from a growth section, a silicon raw material is continuously supplied onto the molten liquid surface of a raw material supply section from a raw material supply pipe, and a high melting point metal tube or quartz is placed near the silicon raw material supply pipe. A manufacturing method in which a raw material supply pipe is directly or indirectly cooled by a cooling gas introduced into the pipe, and a raw material supply pipe that supplies a silicon raw material onto a molten liquid surface of a raw material supply section, and a high temperature cooling system that cools the raw material supply pipe. This is a manufacturing device equipped with melting point metal tubes or quartz tubes.

[Function] The present invention provides a method and apparatus for producing a silicon single crystal, in which a high melting point metal tube or a quartz tube is arranged around the raw material supply tube so that it can be cooled directly or indirectly with gas.
Since the area around the raw material supply pipe is cooled, the silicon raw material can smoothly pass through the raw material supply pipe and can be supplied to the surface of the silicon melt in the raw material supply section B.

[Example] Fig. 1 is a diagram showing an example in which a high melting point metal pipe is arranged so that the periphery of the raw material supply pipe of the present invention can be indirectly cooled with gas. 1 is a raw material supply pipe, and 2 is a high melting point metal pipe that runs along the raw material supply pipe in a spiral shape, and covers the raw material supply pipe 1 up to the vicinity of the outlet 3, so that the radiant heat from the heater and the silicon melt surface is directly absorbed. The high melting point metal tubes 2 are tightly wound so as to be in contact with each other so as not to hit the raw stone supply tube 1 and to prevent the side surface of the raw material supply tube 1 from being irradiated. This high melting point metal tube 2 is arranged so that gas (for example, argon gas) can be introduced from one end C thereof, and is connected to an argon supply device (not shown) located outside the silicon single crystal pulling device. The other end of this high melting point metal tube 2 is open,
Since it is designed to be discharged into the silicon single crystal pulling apparatus, the spirally arranged refractory metal tube 2 is cooled by argon. The arrows in FIG. 9 indicate the direction of movement of the cooling gas.

Since the present invention is configured as described above, the surface temperature of the high temperature object facing the raw material supply pipe 1 side can be lowered compared to the case where the raw material supply pipe 1 is simply covered with a cylindrical object, and the raw material supply The amount of heat radiated to the tube 1 from the high temperature heater and the silicon melt surface can be significantly reduced. Therefore, since the raw material supply pipe 1 can be indirectly cooled and kept at a low temperature, the fine powder contained in the granular silicon raw material is less likely to adhere to the surface of the raw material supply pipe 1 and is deposited in a sintered shape. can be prevented.

In this embodiment, the upper part 50+u from the outlet of the raw material supply pipe 1 is
+ was covered with a tantalum high melting point metal tube 2 arranged in a spiral shape, and argon IONβ/i was flowed as a cooling gas into the tantalum high melting point metal tube 2. Even during long-term operation, there was no clogging of silicon raw materials. Note that it is better if the outer surface of the tantalum high melting point metal tube 2 is coated with high purity quartz, taking into account that the tantalum high melting point metal tube 2 may become a source of contamination.

FIG. 2 is a diagram showing another embodiment of the present invention in which a high melting point metal tube is arranged so that the periphery of the raw material supply tube can be indirectly cooled with gas. The raw material supply pipe 1 is inserted and arranged in the cylindrical tube of the high melting point metal tube 2, which is composed of a double cylindrical tube made of an outer diameter tube 5 and an inner diameter tube 6, and the method shown in FIG. 1 is carried out. As in the example, the high melting point metal tube 2 is arranged so that gas (for example, argon gas) can be introduced from one end C', and is connected to an argon supply device (not shown) outside the silicon single crystal pulling device. There is. The other end D' of this high melting point metal tube 2 is open so that it can be discharged into a silicon single crystal pulling apparatus. Similar effects were obtained with this device. In this device, the partition material 4 is placed inside the double pipe to allow the cooling gas to reach the bottom of the high melting point metal pipe 2 to prevent short baths.

FIG. 3 is a diagram showing an embodiment in which a high melting point metal tube is arranged so that the raw material supply tube can be directly cooled with gas. In this figure, the high melting point metal tube 2 is installed parallel to the raw material supply tube, and openings 7 are arranged at appropriate intervals. Opening 7
The shape is generally round or slit. Since this embodiment is configured as described above, the raw material supply pipe 1 is injected directly from the small hole or slit (not shown) of the high melting point metal pipe, so the raw material supply pipe 1 is forcibly cooled. 9 In this embodiment, 6 small holes were arranged at 101 pitches from 51 above the outlet 3 of the raw material supply pipe 1, and the high melting point metal pipes 2 were arranged. The amount of cooling argon gas supplied to the high melting point metal tube 2 was 5 N I /nl1n. From the results of this device, the outlet section 3 of the raw material supply pipe 1 is similar to the previous example.
No clogging of nearby granular silicon raw materials occurred.

In addition, this device directly sprays cooling argon gas onto the surface of the raw material supply pipe 1, but even after spraying about 20 N 127*, no fluctuations in the silicon melt level or scattering of granular silicon raw materials were observed. It did not inhibit the growth of single crystals.

In the present embodiment, the high melting point metal tube 2 with the opening 7 is explained as an example of two tubes, but the same effect can be obtained even with a plurality of tubes. As the material of the high melting point metal tube 2, a high purity quartz tube was also used in addition to tantalum. Although argon gas was used as the gas in all the embodiments of the present invention, other gases may be used as long as they do not interfere with the growth and quality of the silicon single crystal.

In addition, if the indirect cooling method is used as shown in Figures 1 and 2, the gas used for cooling can be guided to the outside of the silicon single crystal pulling equipment and exhausted, thereby reducing the amount of gas that can be used for cooling. The number of types can be further increased.

[Effects of the Invention] As described above, according to the present invention, in the method and apparatus for pulling a silicon single crystal, there is provided a raw material supply pipe that continuously supplies a silicon raw material onto the molten liquid surface of a raw material supply section; A high-melting point metal tube or quartz tube is installed to cool the tube, so the turbidity of the raw material supply tube is cooled, and granular silicon raw materials can be prevented from adhering inside the raw material supply tube. No clogging occurred.

[Brief explanation of the drawing]

Section 1 is a diagram showing an embodiment in which a high melting point metal tube is arranged so that the area around the raw material supply pipe of the present invention can be indirectly cooled with gas, and Figure 2 shows the area around the raw material supply pipe of the present invention. Figure 3 shows another embodiment in which a high melting point metal tube is installed so that the raw material supply section can be cooled indirectly with gas. Embodiment FIG. 4 is a diagram showing a conventional silicon single crystal pulling apparatus. 1. Raw material supply pipe, 2.. High melting point metal tube, 3.. Outlet part of high melting point metal tube, 4.. Partition material for high melting point metal tube, 5..
- Outer diameter pipe, 6... Inner diameter pipe, 7... Opening.

Claims (5)

[Claims] (1) A crucible containing molten silicon is partitioned by a partition member between an inner silicon single crystal growth section and an outer raw material supply section for supplying silicon raw material, and the silicon raw material is continuously supplied to the raw material supply section. In the method of producing a silicon single crystal from the single crystal growth section, the molten silicon is gently transferred to the single crystal growth section through the small holes of the partition member while being melted. The raw material supply pipe is cooled directly or indirectly by gas that is continuously supplied onto the molten liquid surface of the supply section and introduced into a high melting point metal tube or quartz tube arranged near the raw material supply pipe. Characteristics of the manufacturing method for silicon single crystals. (2) A crucible containing molten silicon is divided by a partition member into an inner single-crystal silicon crystal growth section and an outer raw material supply section that supplies silicon raw material, and the silicon raw material is continuously supplied to the raw material supply section. In an apparatus for manufacturing a silicon single crystal from the single crystal growth section by gently moving the molten silicon through the small holes of the partition member to the single crystal growth section while melting the silicon raw material in the raw material supply section while supplying the silicon raw material, A silicon unit characterized in that a raw material supply pipe for supplying a silicon raw material onto the molten liquid surface of a raw material supply section and a high melting point metal tube or a quartz tube for cooling the raw material supply pipe directly or indirectly are arranged. Crystal manufacturing equipment. (3) The silicon single crystal manufacturing apparatus according to claim 2, wherein a high melting point metal tube or a quartz tube is arranged spirally to surround the outer surface of the raw material supply tube. (4) The raw material supply pipe is inserted into a cylindrical cylinder of a high-melting point metal tube or a quartz tube, which is made up of a double-cylindrical tube with an outer diameter tube and an inner diameter tube. 3. The silicon single crystal manufacturing apparatus according to claim 2. (5) Production of the silicon single crystal according to claim 2, characterized in that one or more high-melting point metal tubes or quartz tubes having a plurality or more openings are arranged along the vicinity of the raw material supply tube. Device.