JP2013147406A - Method for producing silicon single crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a silicon single crystal, by which the occurrence of dislocations in the silicon single crystal can be suppressed.SOLUTION: A method for producing a silicon single crystal includes melting a raw material charged in a pulling machine into a silicon melt, then bringing a seed crystal into contact with a melt surface of the silicon melt, and growing the silicon single crystal by pulling the seed crystal upward. In the method, after setting components used in a furnace in the pulling machine, the inside of the pulling machine is evacuated before the raw material is charged.

Description

  The present invention relates to a method for producing a silicon single crystal using a pulling machine.

  In the Czochralski method (CZ method), the inside of the furnace is disassembled after the completion of the batch, the respective parts are cleaned, and the powder and deposits adhered to the inner wall of the chamber and in-furnace parts mainly made of carbon are removed. After that, the furnace parts are set again, the raw material is charged into the quartz crucible, and the production of the silicon single crystal is resumed.

  In Patent Document 1, moisture is adsorbed to the internal parts of the furnace when the furnace is opened, and the exhaustion of the carbon parts becomes severe due to the influence, the influence of the change with time of the furnace, the mixing of carbon into the crystal, molten silicon and carbon Reacts to produce SiC, which is taken into the growing crystal and converted to dislocation, and a method for removing this adsorbed moisture is described. Specifically, first, a silicon single crystal is taken out, then the furnace is opened to the atmosphere and the inside of the furnace is cleaned, and raw materials are charged for the next crystal growth. It is described that the furnace is then assembled and evacuated to shift to a single crystal growth process. That is, in Patent Document 1, in order to remove adsorbed moisture, vacuuming is performed after raw materials are charged.

JP 2009-167073 A

  However, when vacuuming is performed after the raw materials are charged into the puller, fine powder that cannot be removed during the dismantling and cleaning of the in-furnace parts is scattered in the puller and enters the raw material in the quartz crucible. From this, it was found that the silicon single crystal may be dislocated.

  This invention is made in view of the said problem, Comprising: It aims at providing the manufacturing method of the silicon single crystal which can suppress that a silicon single crystal originates in dislocation | rearrangement resulting from the disassembly cleaning of the in-furnace components. To do.

The present invention has been made in order to solve the above-described problem, and melts a raw material charged in a pulling machine to form a silicon melt, a seed crystal is brought into contact with the melt surface of the silicon melt, A silicon single crystal manufacturing method for growing a silicon single crystal by pulling a seed crystal upward,
Provided is a method for producing a silicon single crystal, characterized in that after the in-furnace parts are set in the pulling machine and before the raw materials are charged, the pulling machine is evacuated.

  By vacuuming the inside of the pulling machine before charging the raw material in this way, it is possible to remove powder generated during the dismantling cleaning of the pulling machine. Dislocation can be suppressed.

  Further, when evacuating the inside of the pulling machine, it is preferable to evacuate while heating.

  By heating in this way, powder etc. can be removed more effectively.

Furthermore, when evacuating the inside of the pulling machine, it is preferable to evacuate the vacuum level to 1 × 10 ⁻² hPa or less.

  With such a degree of vacuum, the powder can be removed sufficiently efficiently.

  As described above, in the method for producing a silicon single crystal of the present invention, the powder generated during the dismantling cleaning of the puller is removed by evacuating the puller before charging the raw material. It is possible to suppress dislocation of the silicon single crystal by charging the raw material thereafter. Thereby, the productivity of a single crystal can be remarkably improved.

  Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto. As described above, a method for producing a silicon single crystal that can suppress the dislocation of the silicon single crystal has been desired.

  The present inventors have intensively studied to solve the above problem, and a method for avoiding dislocation of the silicon single crystal derived from fine powder that could not be removed during disassembly cleaning. The headline and the present invention were completed. Hereinafter, the present invention will be described in more detail.

  That is, in the method for producing a silicon single crystal according to the present invention, after dismantling and cleaning of the in-furnace parts, the in-furnace parts are set in the pulling machine, and then the inside of the pulling machine is evacuated before charging the raw material into the quartz crucible. As described above, after the dismantling and cleaning are completed, the furnace is once assembled and evacuated before charging the raw materials, so that fine powder that cannot be completely removed from the chamber and in-furnace parts can be removed. In the CZ method, a large amount of powder such as SiO is generated. Therefore, even if this is cleaned, it is difficult to remove it completely. In addition, because the in-furnace parts are mainly made of carbon material, dust is easily generated from the surface. Accordingly, after cleaning, after setting the in-furnace parts in the pulling machine, a large amount of dust is fluttered and removed while floating in the pulling machine at the time of the first vacuuming. At this time, since the raw material was simultaneously present in the pulling machine at the same time, it caused dislocations in the subsequent pulling of the single crystal, but in the present invention, after the furnace parts were once set in the pulling machine, the vacuum By removing the dust by pulling, and then charging the raw material, it is possible to prevent dislocation of the silicon single crystal resulting from disassembly and cleaning.

  Moreover, when evacuating the inside of the said pulling machine, powder etc. can be removed more effectively by evacuating while heating. The heating at this time is not particularly limited, but it is more preferably 100% or less, particularly about 50 to 90% with respect to the electric power at the time of melting the raw material.

Further, when evacuating the pulling machine, it is preferable to evacuate the vacuum reaching degree below 1 × 10 -2 ^hPa, it is more preferable to evacuate the vacuum reaching degree below 1 × 10 -3 ^hPa The lower the vacuum reach, the better. Thereby, powder, moisture, etc. can be removed sufficiently efficiently.

  After that, once the furnace is opened to the atmosphere to charge the raw material, the raw material is immediately charged, and vacuuming is performed again to move to the silicon single crystal growth process. Single crystals can be produced. The silicon single crystal growth process can be performed by any of the generally used methods. The raw material charged in the puller is melted to form a silicon melt, and a seed crystal is formed on the melt surface of the silicon melt. There is no particular limitation as long as it is a process for growing a silicon single crystal by bringing it into contact and pulling the seed crystal upward.

  EXAMPLES Hereinafter, although the Example and comparative example of this invention are given and demonstrated further in detail, this invention is not limited to the following Example.

[Examples 1-4, comparative example]
After the raw material preparation pretreatment shown in Table 1, polycrystalline silicon was charged. Thereafter, the polycrystalline silicon charged in the puller was melted to form a silicon melt, a seed crystal was brought into contact with the melt surface of the silicon melt, and the seed crystal was pulled upward to grow a silicon single crystal. The molten polycrystalline silicon was 400 kg, and a silicon single crystal having a diameter of 300 mm was produced. In addition, the inside of the furnace of the lifting machine was dismantled and cleaned each time one was pulled up. This was repeated 10 times to produce 10 silicon single crystals. The total number of dislocations at this time is shown in Table 1.

  In Table 1, the implemented processing is indicated by ◯, and the processing not performed is indicated by ×. Moreover, about Example 4, it heated during the vacuuming of raw material preparation pre-processing.

In Examples 1 to 3, heating was not performed, but only evacuation was performed before the raw materials were charged. When the ultimate vacuum was 5 × 10 ⁻¹ hPa, the number of dislocations at 1 × 10 ⁻² hPa was 1 × 1 × 10 ⁻³ hPa, although the number of dislocations was 1 × 10 ⁻² hPa. The number of dislocations of was very good at 0 times.

In Example 4, evacuation was performed while heating. The heater power during heating was 80% of the power during melting of the raw material, and the ultimate vacuum was 1 × 10 ⁻² hPa. At this time, ten silicon single crystals could be obtained without any dislocation, and the production efficiency was very high.

  In the comparative example, heating and evacuation were not performed in advance, the raw material was charged immediately after the dismantling cleaning, and after vacuuming, a silicon single crystal was grown. At this time, dislocation occurred 8 times in the process of producing 10 crystals, which was very inefficient.

The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

Claims (3)

A silicon single crystal for growing a silicon single crystal by melting the raw material charged in the pulling machine into a silicon melt, bringing the seed crystal into contact with the melt surface of the silicon melt, and pulling the seed crystal upward A manufacturing method comprising:
A method for producing a silicon single crystal, wherein after the parts in the furnace are set in the pulling machine, the inside of the pulling machine is evacuated before the raw material is charged.   The method for producing a silicon single crystal according to claim 1, wherein when the inside of the pulling machine is evacuated, the evacuation is performed while heating. 3. The method for producing a silicon single crystal according to claim 1, wherein when the inside of the pulling machine is evacuated, the degree of vacuum is evacuated to 1 × 10 ⁻² hPa or less.