JP4198806B2 - Rotating shaft for silicon single crystal pulling device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a member for constituting the silicon single crystal pulling apparatus, in particular, it relates to the rotation axis of the silicon single crystal pulling apparatus for rotating and vertically moving a crucible for melting divorced material .
[0002]
[Prior art]
A silicon single crystal pulling apparatus pulls up a silicon single crystal from a silicon melt in a crucible in the presence of an atmospheric gas by a so-called Czochralski method. For example, Japanese Patent Publication No. 57-15079 discloses. Is known as a “single crystal pulling device”. As shown in FIG. 2, the apparatus disclosed in this publication is “a rotating shaft 2 is introduced into a furnace body container 1 from below, and a crucible 4 is disposed on an end surface of the rotating shaft 2 via a tray 3. A heating element 5 and a heat insulating cylinder 6 are arranged around the crucible 4, and silicon is melted in the crucible 4 to obtain a melt 7. On the other hand, a rotating shaft that slides up and down above the furnace body container 1. A silicon seed crystal 8 is attached to the free end of the rotating shaft 9, and the rotating shaft 9 is moved upward from a state where the seed crystal 8 is in contact with the melt 7 in the crucible 4. The silicon single crystal 10 that follows the seed crystal 8 is obtained, and it is necessary to eliminate this so that unnecessary reaction product gas does not react on the liquid surface of the single crystal 10 and the melt 7 when the single crystal is grown. For this purpose, an inert gas such as argon is used as the atmosphere gas, and a single crystal is formed from above the furnace vessel 1. Is supplied to the beauty liquid surface, is that discharged from the furnace vessel bottom "(column 2 of the above publication).
[0003]
By the way, in the single crystal manufacturing apparatus described above, the rotating shafts 2 and 9 not only rotate and move up and down while supporting the crucible, but if the rotating shafts 2 and 9 are damaged, the crucible falls, In the worst case, there is a risk that the molten silicon will destroy the partition walls of the cooling layer and cause a steam explosion. Therefore, a graphite material is usually used as a material for constituting the rotating shaft as described above.
[0004]
[Problems to be solved by the invention]
However, with the recent increase in diameter of silicon single crystals, quartz crucibles and graphite crucibles have become larger, and the weight of silicon raw material contained in the quartz crucible reaches as much as 500 kg in the case of a 16-inch φ wafer. Accordingly, the stress on the rotating shaft also increases, and there is a problem in strength.
[0005]
To increase the strength of the rotating shaft, there is a method of increasing the diameter of the rotating shaft, but if the diameter of the rotating shaft is increased, the amount of heat taken away from it increases, resulting in the temperature of the silicon melt in the crucible. distribution becomes non-uniform, it is necessary to increase supply amount of heat from the heater motor 2 0 around to make up for deprived the rotation axis heat problem life of the crucible 10 and the heater motor 2 0 Therefore is shortened There is also a problem that the thermal efficiency becomes worse. Further, if the temperature distribution in the silicon melt is not uniform, the quality of the pulled silicon single crystal is adversely affected.
[0006]
Therefore, the present inventors have completed the present invention as a result of various studies on how to solve the above-described problems with respect to the rotating shaft for this type of silicon single crystal pulling apparatus.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the means adopted the invention according to 請 Motomeko 1 is explained with reference numeral used in the description of the following embodiments, a crucible for melting "divorced material 10 is a rotary shaft 60 for a silicon single crystal pulling device, which is disposed at the lower part of the rotary shaft 10 and rotates and moves the crucible 10 up and down, and is an annular C that is fitted or embedded in a rotary shaft body made of graphite. silicon / C-composite 61 possess, said that with some rotation axis body and said annular C / C composite 61 or the entire surface pyrolytic carbon is impregnated, characterized in that the pyrolytic carbon film is formed This is a rotating shaft 60 "for a single crystal pulling apparatus.
[0008]
That is, the rotary shaft 60 for the silicon single crystal pulling apparatus according to the first aspect of the invention is disposed at the lower part of the crucible 10 in the sealed body 50 as shown in FIG. 1, and rotates and moves the crucible 10 up and down. As shown in FIG. 3, an annular C / C composite 61 is fitted or embedded in the shaft body .
[0009]
The C / C composite 61 fitted to the rotary shaft 60 for the silicon single crystal pulling apparatus has high strength and is formed as follows. First, carbon fibers are uniaxially or multiaxially oriented to form a cylindrical material, which is impregnated with resin and carbonized. Examples of the resin used for impregnation include tar and pitch in addition to resins such as phenol and furan.
[0010]
The rotation shaft of the silicon single crystal pulling apparatus according to claim 1, and more and this having an annular C / C component sit 61 formed by fitting the rotation shaft body consisting of graphite, C / C component Sit 61 Is present in the circumferential direction with respect to the central axis, so that the strength is significantly increased. Therefore, it is possible to reduce the diameter while giving the strength as much as possible, and it is possible to minimize the loss of heat of the silicon melt.
[0011]
Further, the rotary shaft main body and the ring-like C / C composite 61 is the content that some or entire pyrolytic carbon is impregnated with Rutotomoni pyrolytic carbon coating formed. The reason for this configuration is that the pyrolytic carbon film prevents SiO gas or Si vapor generated when pulling up the silicon single crystal from coming into contact with the C / C composite substrate. ) And a decrease in strength due to silicification and Si penetration.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described with reference to the embodiments shown in the drawings. FIG. 1 is a longitudinal sectional view of a silicon single crystal pulling apparatus 100 to which a rotating shaft 60 for a silicon single crystal pulling apparatus according to the present invention is applied. Is shown.
In this silicon single crystal pulling apparatus 100, a crucible 10 for melting silicon is accommodated in a hermetically sealed main body 50 so as to be rotatable and vertically movable by a rotating shaft 60.
[0013]
A rotating shaft 60 for a silicon single crystal pulling apparatus has an annular C / C composite 61 fitted to a rotating shaft body made of graphite as shown in FIG. Or the rotating shaft 60 has the cyclic | annular C / C composite 61 embed | buried under the rotating shaft main body which consists of graphite as shown in FIG. Furthermore, the rotating shaft body and an annular C / C composite 61 is fitted to the body is are partially or entirely pyrolytic carbon is impregnated with Rutotomoni pyrolytic carbon coating is formed. These C / C composites and pyrolytic carbon coatings are manufactured or formed as shown in the following examples.
[0014]
[ Reference Example 1]
First, a cloth knitted with carbon fibers was used to form an annular shape by a winding method, and this carbon fiber material was impregnated with a phenol resin and cured at 900 ° C. after curing. Further, phenol resin impregnation, curing and firing were repeated twice to graphitize to obtain a cyclic C / C composite.
[0015]
The obtained annular C / C composite was fitted to a rotating shaft for a 32 inch φ crucible obtained by processing graphite.
[0016]
[Example 1 ]
A cyclic C / C composite was formed in the same manner as in Reference Example 1.
[0017]
The obtained annular C / C composite was put in a CVD furnace and heated to 1400 ° C., and methane gas was continuously supplied into the furnace using hydrogen gas as a carrier. As a result, the entire surface of the equipment was impregnated with pyrolytic carbon to a depth of 30 μm from the surface, and a pyrolytic carbon coating having a thickness of about 50 μm was formed on the surface. The obtained annular C / C composite was fitted to a rotating shaft for a 32-inch φ crucible obtained by processing graphite.
[0018]
【The invention's effect】
As described above in detail, in the present invention, as exemplified in the above embodiment, “the silicon single crystal pulling apparatus 100 is disposed below the crucible 10 for melting the silicon material, and the crucible 10 is rotated and rotated. A rotary shaft 60 for a silicon single crystal pulling device for moving up and down, and having an annular C / C composite 61 fitted or disposed on a rotary shaft main body made of graphite, Part of the main body and C / C composite or the entire surface is impregnated with pyrolytic carbon and has a pyrolytic carbon coating, ”which has a structural feature, thereby making silicon with high strength and high durability. A rotating shaft for a single crystal pulling apparatus can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic vertical sectional view of a silicon single crystal pulling apparatus employing a rotating shaft according to the present invention.
FIG. 2 is a cross-sectional view showing a conventional silicon single crystal pulling apparatus.
FIG. 3 is an enlarged cross-sectional view of a rotating shaft for a silicon single crystal pulling apparatus according to the present invention.
[Explanation of symbols]
100 Silicon single crystal pulling apparatus 10 Crucible 11 Quartz crucible 20 Heater 30 Insulating tube 40 Insulating material 50 Sealed body 60 Rotating shaft 61 C / C composite

Claims (1)

Divorced material is disposed in the lower portion of the crucible for melting, a rotating shaft of the silicon single crystal pulling apparatus for rotating and vertically moving the crucible,
Having an annular C / C composite fitted or embedded in a rotating shaft body made of graphite,
The rotary shaft for a silicon single crystal pulling apparatus, wherein the rotary shaft main body and the annular C / C component are partially or entirely impregnated with pyrolytic carbon and a pyrolytic carbon film is formed. .

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