JPH027917B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a graphite crucible holder used when producing a single crystal by pulling up molten silicon in a quartz glass crucible.

Generally, silicon single crystals are manufactured by a pulling method. This involves melting a block of high-purity polycrystalline silicon in a quartz glass crucible and pulling it up using a seed crystal, but the processing temperature reaches 1450°C, which causes the quartz glass crucible to soften and deform. For this reason, the quartz glass crucible is supported by a crucible holder made of graphite. This quartz glass changes its surface to silicon carbide when it comes into contact with graphite, and because it has a large difference in expansion and contraction from graphite, graphite crucible holders are often damaged when the temperature rises and falls.

For this reason, a split graphite crucible holder has been proposed (for example, Japanese Utility Model Publication No. 52-27880), but the silicon carbide reaction is particularly severe at the periphery of the bottom of the crucible, and cracks occur in this area, making it unusable. There were many things that happened. The silicon carbide layer that forms on the periphery of the bottom is concentrated in a width of about 10 mm on the top and bottom, which has been an obstacle in achieving larger size and continuity.

The present invention has been made to solve these drawbacks of crucible holders, and the shape of the bottom periphery, where cracks are particularly prone to occur, has been improved to create a structure that can accommodate upsizing and continuous crucible holders. In a graphite crucible holder comprising a pedestal part forming the bottom part of the tool and a cylindrical part forming the side part, the holder is inserted into the cylindrical part and placed on the pedestal part to support the periphery of the bottom of the silica glass crucible. An annular spacer is provided for this purpose.

An embodiment of the present invention will be described below with reference to the drawings.

In the figure, reference numeral 1 denotes a pedestal section for supporting the bottom of the quartz glass crucible, and a cylindrical section 3 constituting a side portion is fitted into an outer peripheral edge 2 of this pedestal section 1. The cylindrical part 3 is divided into two parts 3' and 3'' in the axial direction, and a ring-shaped spacer 4 is inserted into the corner formed by the lower part of the cylindrical part and the pedestal part. The spacer 4 is for supporting the bottom periphery of the quartz glass crucible, and at the same time, if a silicon carbide layer is formed by reaction with the quartz glass, by replacing only this part, the side and The purpose is to reuse the bottom part.

The crucible holder of the present invention is constructed as described above, and the cylindrical portion is provided with at least one slit in the axial direction, so that no pressure that may cause damage during expansion and contraction of the quartz glass can be applied. I won't receive it. Furthermore, even if a silicon carbide layer were to be formed on a part of the lower part, since the silicon carbide layer has a vertically symmetrical cylindrical shape, it would be easy to remove the silicon carbide layer from the outer periphery of the pedestal by cutting that part or turning it upside down (inverting it). It can be fitted to In the embodiment, there were two slits in the axial direction, that is, two arcuate pieces were combined to form a cylindrical body, but even if there is only one slit, it is hardly affected by the expansion and contraction of the quartz glass. Alternatively, the cutting direction of the slit 5 may be shifted from the radial direction as shown in FIG. Furthermore, since the parts that react with the quartz glass and break are concentrated in the spacer part, the service life of the cylindrical part and the frame part can be extended by replacing only this part.

The shape of the spacer may be such that it is inserted into the corner of the pedestal part and the cylindrical part so that a step part is not formed as a crucible holder, and may be appropriately selected depending on the shape of the pedestal part. The pedestal supports most of the weight of the quartz glass crucible and molten silicon, and its shape is designed taking heat distribution etc. into account. Alternatively, as shown in FIG. 4, it may be a relatively flat plate having almost no concave curved surface.

In addition, in FIG. 4, 6 is a pin for fixing the position of the spacer and the pedestal part. Further, 7 is a ring for adjusting the height of the cylindrical portion when the lower end portion of the cylindrical portion is cut and removed. If the cylindrical part 3 is a combination of two or more parts, it may be made to stand on its own on a pedestal part, and if necessary, a mechanism for preventing it from falling down, such as an external fitting ring, may be employed. However, as shown in FIG. 2, if one slit or cut is made, the upper end or the lower end is left, and the cylindrical part alone can easily stand on its own.

As described above, according to the present invention, the annular spacer is the part where the silicon carbide reaction in the quartz glass crucible is particularly severe and breaks, so by replacing only this annular spacer, the damaged part can be effectively renewed. Compared to conventional techniques, the service life of the pedestal part and the cylindrical part can be significantly extended, and as a result, larger and more continuous silicon single crystals can be pulled.

[Brief explanation of drawings]

The figures show an embodiment of the present invention, with FIG. 1 being a schematic sectional view, FIG. 2 being a schematic plan view showing another embodiment, and FIG.
4 are schematic sectional views showing other embodiments. 1... Frame, 2... Outer periphery, 3... Cylindrical part,
4...Spacer, 5...Slit, 6...Pin.

Claims (1)

[Claims] 1. Made of graphite for producing silicon single crystals, comprising a pedestal part constituting the bottom, and a cylindrical part placed on or fitted to the outer peripheral edge of the pedestal part and constituting a side part provided with at least one slit. In the crucible holder,
A graphite crucible holder for producing a silicon single crystal, comprising an annular spacer inserted into the cylindrical part and placed on the pedestal part to support the periphery of the bottom of the quartz glass crucible.