JPH0566351B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a method for manufacturing silicon perforations.

[Technical background of the invention]

Silicon single crystals are mainly produced by the Czyochralski method. In this method, a crucible is rotatably supported in a chamber, a polysilicon raw material is loaded into the crucible, the polysilicon raw material is heated by a carbon heater placed around the crucible, and then the polysilicon raw material is melted. A silicon single crystal is grown by dipping a seed crystal into silicon and pulling it up.

Conventionally, the charging of polysilicon raw material into a crucible has been carried out by simply filling, for example, a block of polysilicon raw material 2 into a quartz crucible 1, as shown in FIG.

In the charging method shown in FIG. 2, when the polysilicon raw material is heated and melted, the surface of the molten silicon is considerably lower than the upper end of the crucible 1.

[Problems with background technology]

In the above-mentioned Czyochralski method, it is clear that in order to increase the production amount of silicon single crystals, it is sufficient to increase the charge amount of the polysilicon raw material. On the other hand, in order to improve the quality of silicon single crystals, it has been found that it is desirable to lower the height of the crucible to reduce the temperature gradient of molten silicon. Both of the above-mentioned increases in production volume and improvements in quality lead to improvements in the yield of silicon single crystals.

However, when the polysilicon raw material is charged by the conventional method as shown in FIG. 2, the positional relationship between the molten silicon and the upper end of the crucible does not change much depending on the height of the crucible. For this reason, when charging polysilicon raw materials in a low-height crucible using the conventional method with emphasis on the quality of silicon single crystals, the depth of the molten silicon melt becomes shallow and the amount of raw material charged decreases. As a result, the production amount of silicon single crystals will decrease. Therefore, there was a drawback that the yield of silicon single crystals did not improve as much as expected.

[Purpose of the invention]

The present invention was made in consideration of the above circumstances, and it significantly improves the yield by increasing the amount of silicon raw material charged into a crucible with a low height, improving quality and increasing production volume. The purpose of the present invention is to provide a method for producing silicon single crystals.

[Summary of the invention]

In the method for producing a silicon single crystal of the present invention, a cylindrical body made of silicon having a height higher than the height of the crucible is housed in a crucible, a silicon raw material is loaded into the cylindrical body, and then the silicon raw material and the silicon raw material are heated. It is characterized by melting a cylindrical body.

According to this method, even if the height of the crucible is low, by changing the height of the silicon cylindrical body, it is possible to charge an amount of silicon raw material that completely fills the crucible. Therefore, it is possible to improve the quality of the silicon single crystal and increase the production amount, thereby significantly improving the yield.

In the present invention, the silicone cylindrical body may be a simple cylindrical body or may be a container provided with a bottom surface. Further, the cross-sectional shape of the cylindrical body can be cylindrical or any other arbitrary shape.

[Embodiments of the invention]

Hereinafter, embodiments of the present invention will be described with reference to a lifting device shown in FIG.

In FIG. 1, a lower chamber 11 is provided with openings on its top and bottom surfaces, and a pull chamber 1 for pulling a silicon single crystal is provided above the opening.
2 is provided. A support shaft 13 is rotatably inserted through an opening at the bottom of the lower chamber 11.
A protector 14 made of graphite and a crucible 15 made of quartz or the like inside the protector 14 are supported at its upper end. A cylinder 16 formed by welding a silicon body is housed in the crucible 15, and a polysilicon raw material 17 is loaded inside the cylinder.

Further, electrodes 18, 18 are inserted into the lower chamber 11 through its bottom surface, and are connected to the carbon heater 8 provided above the protector 4 so as to surround the protector 4. Furthermore, a heat retaining cylinder 20 is arranged around the outer periphery of the carbon heater 19.

Pulling of a silicon single crystal using the above-mentioned pulling apparatus is carried out as follows. That is, first, polysilicon raw materials and impurities are loaded into a cylindrical body 16 made of silicon housed in a crucible 15, and the pressure is reduced while flowing an inert gas.
Next, from the electrodes 18, 18, the carbon heater 19
The polysilicon raw material 17 and the cylindrical body 16 in the crucible 15 are melted by applying electricity to and heating the crucible. Next, a seed crystal (not shown) is immersed in the molten silicon while the crucible 15 is being rotated, and a silicon single crystal is grown by pulling up the seed crystal while rotating the pulling shaft holding the seed crystal.

According to such a method, even when the height of the crucible 15 is low, by changing the height of the cylinder 16, it is possible to charge the polysilicon raw material until it completely fills the crucible 15 when melted.

In fact, when the diameter of the crucible is 14 inches, in the conventional charging method for polysilicon raw materials, the crucible height is 250 mm and the maximum charge amount is 25 kg, but with the method of the present invention, the crucible height is 200 mm and the maximum charge amount is 25 kg. We were able to increase the charge amount to 30Kg. It was also confirmed that it was possible to charge enough polysilicon raw material into a crucible of any height to completely fill the top of the crucible.

Therefore, according to the method of the present invention, it is possible to improve the quality of the silicon single crystal pulled by uniformizing the temperature distribution of the molten silicon in the crucible, and to increase the production amount, thereby significantly improving the yield. I can do it.

〔Effect of the invention〕

As detailed above, according to the method of the present invention, the yield of silicon single crystals can be significantly improved,
In addition, it will be able to fully cope with future increases in the diameter of silicon single crystals.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a silicon single crystal pulling apparatus for explaining a method for charging a polysilicon raw material in an embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional method for charging a polysilicon raw material. 11... Chamber, 12... Pull chamber, 13... Support shaft, 14... Protective body, 15...
Crucible, 16... Cylinder, 17... Polysilicon raw material, 18... Electrode, 19... Carbon heater,
20...Thermos cylinder.

Claims (1)

[Claims] 1 A crucible is rotatably supported in a chamber,
In order to produce a silicon single crystal by melting a silicon raw material in this crucible, dipping a seed crystal into the molten silicon, and pulling it up, a cylindrical body made of silicon with a height higher than the height of the crucible is placed in the crucible. 1. A method for producing a silicon single crystal, the method comprising: filling the cylindrical body with a silicon raw material; and heating the cylindrical body to melt the silicon raw material and the cylindrical body.