JP2003289048A - Deformation preventing jig for silica glass reactor core tube for heat treatment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a deformation preventing jig of a silica glass reactor core pipe for heat treatment capable of lengthening the life of the silica glass reactor core pipe even if being thin in thickness, and reducing heat treatment costs. <P>SOLUTION: This deformation preventing jig of an arcuate shaped silica glass reactor core pipe for heat treatment is made of silicon carbide, and has an external diameter r<SB>11</SB>and an internal diameter r<SB>1</SB>of a cylindrical silica glass reactor core pipe 11 used for a horizontal furnace wherein the cross-section of a site 2 where the silica glass reactor core pipe 11 is held is formed at arcuate angles θ ranging from 90° to 200°. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jig for preventing deformation of a silica glass for heat treatment, particularly a synthetic quartz glass furnace core tube, and more particularly to a silica glass furnace tube made of silicon carbide. The present invention relates to a jig for preventing deformation of a silica glass furnace tube for heat treatment, which has the same inner diameter as the outer diameter and has an arc-shaped cross section. 2. Description of the Related Art Conventionally, in the case of a horizontal silica glass furnace core tube used for heat treatment with a tubular tube placed sideways, its own weight is gradually deformed by heat treatment for one hundred and several hundred hours, and its diameter is reduced. Will be expanded and the service life will be shortened. [0003] Conventional horizontal silica glass furnace tubes use high-viscosity silica glass in order to extend the life.
Alternatively, the deformation speed has been reduced by increasing the thickness of the silica glass. However, high-viscosity silica glass is expensive, and increasing the thickness of the silica glass increases the amount of material used, so that the silica glass furnace core tube becomes expensive and the heat treatment cost increases. there were. [0004] Therefore, there has been a demand for a jig for preventing deformation of a silica glass furnace core tube for heat treatment which can achieve a long life even with a thin silica glass furnace core tube and can reduce the cost of heat treatment. The present invention has been made in view of the above-described circumstances, and provides a jig for preventing deformation of a silica glass furnace core tube for heat treatment which can achieve a long life even with a thin silica glass furnace core tube and can reduce heat treatment costs. Aim. According to one aspect of the present invention, there is provided a cylindrical silica glass furnace core tube made of silicon carbide and used in a horizontal furnace. The cross-section of a portion having the same inner diameter as the outer diameter and holding the silica glass furnace core tube has an arc shape formed within a range of an arc angle of 90 ° to 200 ° for heat treatment. A jig for preventing deformation of a silica glass furnace tube is provided. As a result, even with a thin silica glass furnace core tube, the service life can be extended, and the heat treatment cost can be reduced. An embodiment of a jig for preventing deformation of a silica glass furnace tube for heat treatment according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view of a jig for preventing deformation of a silica glass furnace tube for heat treatment according to the present invention, and FIG. 2 is a conceptual view showing a use state thereof. As shown in FIGS. 1 and 2, a jig 1 for preventing deformation of a synthetic silica glass furnace core tube for heat treatment according to the present embodiment.
Is an arc body made of silicon carbide, having a circular cross section and extending in the axial direction. The deformation preventing jig 1 preferably has the same inner diameter r ₁ as the outer diameter r ₁₁ of the cylindrical silica glass furnace core tube 11, and the portion 2 holding the silica glass furnace core tube 11 preferably has a diameter of 90 mm. From 200 ° to 200 °, for example 180 °. When θ is smaller than 90 °, the deformation preventing jig 1
When the angle θ exceeds 200 °, the cylindrical silica glass furnace core tube 11 is deformed due to insufficient holding of the cylindrical silica glass furnace core tube 11 by the deformation preventing jig 1. Work becomes difficult. θ is preferably around 180 ° from the viewpoint of manufacturing. However, when the angle exceeds 180 °, it is necessary to change the curvature at one end or both ends (for example, in a flat shape) to facilitate installation of the silica glass tube. Therefore, in order to use the jig for preventing deformation of the silica glass furnace core tube for heat treatment according to the present invention, as shown in FIGS. 2 and 3, a wafer boat 12 on which a large number of semiconductor wafers W are mounted is mounted on a horizontal furnace. The silica glass furnace core tube 11 used in the step 13 is housed in the core tube 11, and then the silica glass furnace core tube 11 is placed on the soaking tube 14 via the deformation preventing jig 1 according to the present invention. It is stored in a horizontal furnace 13. After the storage, the semiconductor wafer W is closed by the heat retaining tube 15, the heater 16 is energized, and the semiconductor wafer W is heat-treated with or without supplying the processing gas into the silica glass furnace core tube 11. In the heat treatment process of the semiconductor wafer W, the self-weight deformation of the silica glass furnace core tube 11 is suppressed by the viscosity and the wall thickness as in the conventional case, but in this heat treatment process, the deformation prevention according to the present invention is prevented. Since the jig 1 is used and the deformation preventing jig 1 prevents the silica glass furnace core tube 11 from being deformed, it is possible to use high-purity silica glass which has a small viscosity and cannot be used alone. Not only that, the wall thickness can be reduced, the silica glass furnace core tube becomes inexpensive, and the heat treatment cost can be reduced. In addition, the action of the deformation preventing jig 1 made of silicon carbide having good heat conductivity suitable for use as a heat equalizing tube promotes soaking in the silica glass furnace core tube 11, and furthermore, the deformation preventing jig. 1 is made of silicon carbide having a coefficient of thermal expansion one order of magnitude larger than that of the silica glass forming the silica glass furnace core tube 11, and the deformation prevention jig 1 supports the silica glass furnace core tube from the outside. Stress does not act on the silica glass furnace core tube 11 even if the thermal expansion difference of
The silica glass furnace core tube 11 is not deformed and damaged.
In addition, even during cooling, the stress preventing the jig 1 from damaging the silica glass furnace core tube 11 is not applied to the silica glass furnace core tube 11, and further, the deformation of the silica glass furnace core tube 11 due to its own weight is caused by the deformation in the horizontal direction. By suppressing the deformation by the deformation preventing jig 1, the entire tube is prevented from being crushed. A jig for preventing deformation of a silica glass furnace tube for heat treatment according to the present invention has a diameter of 230 mm and a silica glass thickness of 4 mm.
mm, and held by a silica glass furnace tube having a shape of 1 mm.
Heat treatment was performed at 200 ° C., and the amount of displacement was measured. The viscosity of the silica glass used was log 13.3 Poise. Results: shown in FIG. As shown in FIG. 4, in the embodiment, almost no displacement was observed even after the passage of time, and the displacement of the upper surface at the time when about 670 hours passed was 0.7 mm. On the other hand, in the conventional example in which the deformation preventing jig was not used, the displacement increased with the passage of time, and it was found that the displacement amount of the upper surface after 4670 hours had elapsed was 45.8 mm. From this, it was found that the displacement amount of the embodiment was extremely small, 1/65 of the displacement amount of the conventional example, and that the life was prolonged. According to the jig for preventing deformation of the silica glass furnace core tube for heat treatment according to the present invention, the life of the silica glass furnace core tube can be extended even with a thin silica glass furnace core tube and the heat treatment cost can be reduced. A jig for preventing deformation of the furnace tube can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a jig for preventing deformation of a silica glass furnace tube for heat treatment according to the present invention. FIG. 2 is a conceptual diagram showing a use state of a silica glass furnace tube for heat treatment according to the present invention. FIG. 3 is a cross-sectional view showing a use state of the silica glass furnace tube for heat treatment according to the present invention. FIG. 4 is a test result diagram in an example. [Description of Signs] 1 Deformation prevention jig 2 Holding portion 11 Cylindrical silica glass furnace core tube 14 Heat equalizing tube θ Arc angle r ₁ Inner diameter r ₁₁ Outer diameter

Claims (1)

Claims: 1. An outer diameter of a cylindrical silica glass furnace core tube, which is made of silicon carbide and is used for a horizontal furnace,
A jig for preventing deformation of the silica glass furnace core tube for heat treatment, wherein a cross section of a portion for holding the silica glass furnace core tube has an arc shape formed in an arc angle range of 90 ° to 200 °. .