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Method for reforming quartz glass crucible

A technology for quartz glass crucibles and crucibles, which is applied in glass molding, glass manufacturing equipment, chemical instruments and methods, etc., and can solve problems such as uneven surfaces, unstable arcs, and difficulty in uniformly heating the inside of crucibles, etc.

Inactive Publication Date: 2007-07-04
SUMCO CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But for this structure with 6 electrodes corresponding to 6 phase currents, as shown in Figure 6, arc discharge is more likely to be formed between electrodes facing each other than between electrodes adjacent to each other, so there is such a problem that The heat of the discharge at the central part surrounded by the electrodes will be significantly greater than the heat at its surrounding parts, making it difficult to uniformly heat the inside of the crucible
[0005] In addition, although the arc can be tilted to heat the wall of the crucible, the arc tends to be unstable at this time, and the device becomes complicated in this conventional electrode structure
Furthermore, although oxyhydrogen flames or plasma flames are also suitable for partial heating, due to partial heating, the reformed surface tends to become uneven, and the treatment time is also long.
In addition, annealing must be carried out when partial heating is carried out, because without annealing, the crucible will crack when cooling

Method used

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  • Method for reforming quartz glass crucible
  • Method for reforming quartz glass crucible
  • Method for reforming quartz glass crucible

Examples

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Effect test

example 1

[0059] For a quartz glass crucible having a crucible diameter of 32 inches a treatment was performed to remove air bubbles just below its inner surface, a heating device with 6 electrodes for a 3-phase alternating current was applied, wherein the radius r of the ring formed by these electrodes Can be extended to more than 1 / 4 of the opening radius R of the crucible, and the conventional electrode structure with 3 electrodes for 3-phase alternating current and 6 electrodes for 3-phase alternating current is also applied, which is carried out for 10 minutes power ups. In addition, single crystal silicon pulling experiments were carried out. The relevant results are shown in Table 1.

[0060] In the reforming process of the present invention, the heating device used has 6 electrodes relative to the 3-phase alternating current. Since the distance between the electrodes can be increased similarly to the above, the bubbles in the bottom and wall of the crucible can be reduced. On ...

example 2

[0063] For the quartz glass crucible with a crucible diameter of 32 inches, the treatment of removing impurities is carried out, and the heating device with 6 electrodes relative to the 3-phase alternating current shown in Figure 1 and the traditional 3-phase alternating current 3-electrode heating device are applied. 10 minutes. In addition, a test of pulling single crystal silicon was carried out. The relevant results are shown in Table 2. An unreformed product is also shown as Comparative Example 2.

[0064] For example, in the reforming treatment of the present invention, the impurities on the crucible wall and bottom have been completely removed. When this reformed crucible is used, the dislocation-free ratio of single crystal silicon is 80%, which is a very high dislocation-free ratio. Wrong ratio. On the contrary, in Comparative Example 1 with 3-phase alternating current flowing through the conventional 3-electrode structure, the contamination portion of the wall was...

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Abstract

A reforming process of a quartz glass crucible in which the quartz glass crucible is reformed by an arc discharge generated by electrodes positioned around a rotational axis and configured to heat an inside surface of the crucible while the crucible is rotated. The process includes arranging electrodes in an electrode structure such that neighboring electrodes are positioned at regular intervals in a ring-like configuration; forming a stable ring-like arc between the neighboring electrodes, without generating a continuous arc between electrodes facing each other across a central portion of the ring-like configuration; heating the inside surface of the crucible; and removing a foreign substance located on the inside surface of the crucible or a bubble located under the inside surface of the crucible.

Description

technical field [0001] The present invention relates to a method for reforming quartz glass crucibles used for pulling single crystal silicon by annular arc discharge, which method is particularly suitable for reforming crucibles with large opening diameters. Background technique [0002] When pulling single crystal silicon from molten silicon, a quartz glass crucible is used as a container for containing the above molten silicon. Traditionally, such crucibles have been produced by arc flame fused silica powder. However, there are oxides of silicon evaporated in the melt (SiO 2 , SiO, etc.) to condense and fall again to the inner surface of the crucible to form foreign matter, or as impurities, metal powder or a substance other than silica adheres and is contained on the inner surface of the crucible to form impurities. In addition, air bubbles contained near the inner surface of the crucible often expand and burst, thereby forming a concave-convex structure on this inner ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C03B20/00C30B15/10C03B19/09C03B29/02C03B32/00C30B29/06
CPCC03B29/02C30B15/10C03B19/095C03B32/00
Inventor 福井正德佐藤贤
Owner SUMCO CORP