JPH10203893A - Highly strong quartz glass crucible and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a highly strong quartz glass crucible whose outer surface is reinforced with a crystallized glass layer, whose main body is not deformed during the growth of a single crystal silicon for a long time, and which can thereby grow the non-rearranged single crystal silicon, by forming the crystallized glass layer on the outer surface of the crucible main body comprising amorphous quartz glass. SOLUTION: In this highly strong quartz glass crucible 10, a crystallized glass layer 12 is formed on the whole outer surface of the crucible main body 11. The crystallized glass layer 12 comprises the crystals and the glass, and has a crystallinity of 5-10% and an average thickness of 0.1-10mm. The method for producing the highly strong quartz glass crucible comprises tightly adhering a carbon-made bottomed cylindrical reinforcing member having an outer surface corresponding to the inner surface of the crucible main body 11 comprising amorphous quartz glass to the inner surface of the crucible main body 11, similarly tightly adhering a carbon-made bottomed cylindrical reinforcing member having an inner surface corresponding to the outer surface of the crucible main body 11 to the outer surface of the crucible main body 11 to nip the crucible main body 11 with both the reinforcing members, thermally treating the assembly in an oxygen atmosphere at 1500-1600 deg.C for 1-20hr to soften the inner and outer surfaces of the crucible main body 11, and subsequently crystallize the softened inner and outer surfaces at temperatures below the softening point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-strength quartz glass crucible used for growing single-crystal silicon by the Czochralski method (hereinafter referred to as CZ method) and a method for producing the same.

[0002]

2. Description of the Related Art In the CZ method, silicon is melted inside an amorphous quartz glass crucible, and a seed crystal touching the upper surface of a silicon melt is pulled upward while gently rotating. The melt that has touched the seed crystal loses heat through the seed crystal, precipitates according to the crystal orientation of the seed crystal when solidifying on the seed crystal, and is pulled up as a single crystal rod (ingot). In recent years, when large-diameter ingots have been manufactured, the size of the components in the growing apparatus inevitably increases, the temperature in the growing apparatus increases, and the temperature of the quartz glass crucible itself also approaches the softening point. .

[0003]

Therefore, in the conventional crucible made of amorphous quartz glass, the crucible is deformed due to the softening phenomenon of the quartz glass during the growth of the single crystal, and the silicon melt cannot be held properly. was there. For this reason,
The single crystal silicon grown by the crucible had a high ratio of dislocations caused by thermal stress during the growth, that is, the ratio of the dislocation crystals. The object of the present invention is to strengthen the outer surface of the crucible with a crystallized glass layer so that the crucible body is not deformed during long-term growth,
Accordingly, it is an object of the present invention to provide a high-strength quartz glass crucible capable of growing dislocation-free single crystal silicon and a method for producing the same.

[0004]

The invention according to claim 1 is
As shown in FIGS. 1 and 2, high strength quartz glass crucibles 10 and 20 each having a crystallized glass layer 12 formed on the outer surface of a crucible body 11 made of amorphous quartz glass. By forming the crystallized glass layer 12 on the outer surface of the crucible main body 11, even if the temperature of the crucible main body reaches the softening point of amorphous quartz glass, the crystallized glass layer 12 maintains the shape of the crucible main body and deforms. prevent. The portion where the crystallized glass layer is formed is not limited to the entire outer surface of the crucible body shown in FIG. 1, but may be a part of the outer surface. In this case, not only a plurality of the outer peripheral surfaces of the peripheral wall of the crucible body 11 shown in FIG. Further, the crystallized glass layer may be formed in a single ring or a plurality of rings (horizontal stripes) on the spot or on the outer peripheral surface without being continuous with the outer surface. In the case of a spotted shape, it is preferable that one or more spotted crystallized glass layers are formed per 1 cm ² of the outer surface of the crucible body.

[0005] The invention according to claim 2 is the invention according to claim 1, wherein a high-strength quartz glass crucible 10 in which a crystallized glass layer 12 is formed on the entire outer surface of a crucible body 11 as shown in FIG. It is. By forming the crystallized glass layer 12 on the entire outer surface of the crucible body 11, the crucible body is covered with the crystallized glass layer, and the high-strength quartz glass crucible 10 having extremely high heat resistance is obtained.

The invention according to claim 3 is the invention according to claim 1, wherein a plurality of crystallized glass layers 12 are formed on the outer surface of the peripheral wall of the crucible body 11 at intervals in the vertical direction as shown in FIG. The high strength quartz glass crucible 20 is obtained. By forming a plurality of crystallized glass layers in the form of a plurality of vertical stripes on the outer surface of the crucible main body 11, the quartz glass crucible 20 can efficiently enhance the durability against high heat with a small crystallization area.

According to a fourth aspect of the present invention, as shown in FIG. 3, an outer surface of a crucible body 11 made of amorphous quartz glass is sprayed with an oxyhydrogen flame 21 in an oxygen atmosphere to form a crystallized glass on the outer surface. This is a method for producing a high-strength quartz glass crucible for forming a layer. Since the outer surface of the crucible body 11 is subjected to high heat treatment by direct heat, a crystallized glass layer can be formed in a short time.

In the invention according to claim 5, as shown in FIG. 4, the crucible body 11 made of amorphous quartz glass is reinforced by applying carbon reinforcing materials 26 and 27 to the inner and outer surfaces thereof. This is a method of manufacturing a high-strength quartz glass crucible in which a reinforced crucible body 11 is heat-treated at a temperature of 1500 to 1600 ° C. in an oxygen atmosphere to form a crystallized glass layer on the outer surface of the crucible body 11. Even if the formed crucible body 11 is raised to its crystallization temperature, the crucible body 11 is reinforced by the reinforcing members 26 and 27, so that the shape of the crucible body 11 does not collapse, and a crystallized glass layer is formed on the inner surface and the outer surface with a uniform thickness. Can be formed.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. As shown in FIG. 1, a high-strength quartz glass crucible 10 according to a first embodiment of the present invention has a crystallized glass layer 12 formed on the entire outer surface of a crucible body 11.
For easy understanding, the thickness of the crucible body 11 is exaggerated (the same applies to FIGS. 2 to 5). In the crystallized glass layer, crystals and glass are mixed, and the degree of crystallinity is 5-10.
0%. Preferably it is 20 to 100%. The average thickness of the crystallized glass layer is 0.1 to 10 mm, preferably 2 to 5 mm. The crystallinity of the crystallized glass layer is 5%
If it is less than 0.1 mm or the average thickness is less than 0.1 mm, the heat resistance of the crucible body will not be sufficiently increased.

A method for manufacturing a high-strength quartz glass crucible according to the first embodiment will be described with reference to FIG. As shown in FIG. 3, a reinforcing member 26 of a bottomed cylinder made of carbon and having an outer surface corresponding to the inner surface is adhered to the inner surface of the crucible body 11 made of amorphous quartz glass. Next, a reinforcing member 27 of a bottomed cylinder made of carbon and having an inner surface corresponding to the outer surface is brought into close contact with the outer surface of the crucible body 11. The two reinforcing members 26 and 27 are fastened by a clamp (not shown), and the crucible body 11 is held between the reinforcing members 26 and 27. The crucible body 11 reinforced in this manner is placed in an oxygen atmosphere at 1500 to 16
Heat treatment at a temperature of 00 ° C. for 1 to 20 hours. Thereby, the inner surface and the outer surface of the crucible body are softened. If the time is less than 1 hour, the softening of the amorphous quartz glass is insufficient, and if the time exceeds 20 hours, the softening proceeds more than necessary, and it becomes difficult to maintain the shape of the crucible body. After the heat treatment, if the softening point is lowered, the softened both sides are crystallized. After removing the reinforcing members 26 and 27, the crucible body having the crystallized glass layers on both surfaces is washed with pure water.

Next, a method of manufacturing a high-strength quartz glass crucible according to a second embodiment will be described with reference to FIGS. The thickness and crystallinity of this crystallized glass layer are the same as in the first embodiment. As shown in FIG. 5, a plurality of high-strength quartz glass crucibles 20 of the second embodiment are formed at intervals in the vertical direction on the outer peripheral surface of the crucible body 11 in which the crystallized glass layer 12 is made of amorphous quartz glass. You. As shown in FIG. 4, the crucible body 11 made of amorphous quartz glass is
On the rotating table 25. The crucible body 1 on the table is placed above the side of the turntable 25.
A nozzle 22 that blows out the oxyhydrogen flame 21 toward the outer surface of the fuel cell 1 is provided. The nozzle 22 is moved up and down by a driving device (not shown). In order to form a crystallized glass layer on the outer surface of the crucible body 11 made of amorphous quartz glass in the form of vertical stripes, the crucible body 11 is fixed in an oxygen atmosphere, and then the nozzle 22 is set horizontally as shown in FIG. Flame 2
The position is adjusted so that the tip of the first piece contacts the outer surface of the upper end of the crucible body 11. When the oxyhydrogen flame 21 is sprayed for a predetermined time, the temperature of the outer surface becomes 1500 to 1600 ° C., and the sprayed outer surface portion softens. Next, the nozzle 22 is slowly lowered. The outer surface where the oxyhydrogen flame is no longer sprayed becomes lower in temperature than the softening point and crystallizes. The nozzle 22 is the crucible body 1
When the rotary table 25 reaches the outer surface at the lower end of the table 1, the rotary table 25 is rotated by a small angle, and after the table 25 stops, the nozzle 22 is raised. When the nozzle 22 reaches the outer surface of the upper end of the crucible body 11, the rotary table 25 is rotated by a small angle, and after the table 25 stops, the nozzle 22 is lowered. Hereinafter, similarly, the raising and lowering of the nozzle and the rotation of the table are alternately performed, so that the oxyhydrogen flame 2
Spray 1 Thereafter, the crucible body having a crystallized glass layer on the outer surface in the form of vertical stripes is washed with pure water.

[0012]

Next, examples of the present invention will be described together with comparative examples. Silicon single crystals are grown using the high-strength quartz glass crucibles of the first and second embodiments described above, and for comparison, a conventional quartz glass crucible having no crystallized glass layer on the outer surface of the crucible body for comparison. did. That is, the processed high-strength quartz glass crucibles of the first and second embodiments (hereinafter, referred to as Examples 1 and 2) which are formed into the same shape and the same size and made of the same amorphous quartz glass. Example 1,
An unprocessed conventional quartz glass crucible (hereinafter, referred to as Comparative Example 1) formed of the same amorphous quartz glass having the same shape and size as that of Comparative Example 2 was installed in the same CZ silicon single crystal growing apparatus, After filling each crucible body with the same polycrystalline silicon and melting the polycrystalline silicon in an inert gas,
The seed crystal was immersed in a silicon melt, pulled up, and manufactured single crystal ingots under the same conditions.

From the presence or absence of habit lines of the single crystal ingots of Example 1, Example 2 and Comparative Example 1, it was examined whether the single crystal ingot grown was a dislocation free crystal or a dislocation crystal. Table 1 shows the percentage of the number of dislocation-free crystals with respect to the total number of grown crystals.

[0014]

[Table 1]

As is clear from Table 1, the ratio of the dislocation-free crystals of the single crystal ingot made from the quartz glass crucible of Comparative Example 1 was 30%, whereas the ratio of Examples 1 and 2 was 30%. Indicates 90% and 89%, respectively, indicating that the high-strength quartz glass crucibles of Example 1 and Example 2 were extremely unlikely to deform during growth.

[0016]

As described above, according to the method of the present invention, a crystallized glass layer is formed on the outer surface of the crucible main body of a quartz glass crucible in contact with the silicon melt, and the high strength quartz glass crucible is used by the CZ method. When a single crystal is manufactured, the crucible body having a crystallized glass layer is more thermally stable than a conventional crucible body made of only amorphous quartz glass, and thus has a higher strength than a conventional crucible. Therefore, a silicon single crystal can be grown without deforming the crucible at a high temperature for a long time, and as a result, a crystal can be produced without dislocation.

[Brief description of the drawings]

FIG. 1 is a central longitudinal sectional view of a high-strength quartz glass crucible according to a first embodiment of the present invention.

FIG. 2 is a central longitudinal sectional view of a high-strength quartz glass crucible according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a method for manufacturing a high-strength quartz glass crucible according to the first embodiment of the present invention.

FIG. 4 is a sectional view showing a method for manufacturing a high-strength quartz glass crucible according to a second embodiment of the present invention.

FIG. 5 is a perspective view of a high-strength quartz glass crucible according to a second embodiment of the present invention.

[Explanation of symbols]

 10, 20 High-strength quartz glass crucible 11 Crucible body 12 Crystallized glass layer 21 Hydrogen oxyflame 26, 27 Reinforcing material

Continued on the front page (72) Inventor Hironari Abe 1-5-1, Otemachi, Chiyoda-ku, Tokyo Within Mitsui Material Silicon Co., Ltd. (72) Inventor Kazutaka Terashima 206-2 Nakano, Ebina City, Kanagawa Prefecture 3 (72) Inventor Susumu Maeda 2612 Shinomiya, Hiratsuka-shi, Kanagawa Prefecture Inside Komatsu Electronic Metals Co., Ltd. (72) Hideo Nakanishi 1-26-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Toshiba Ceramics Corporation

Claims (5)

[Claims] 1. A crucible body made of amorphous quartz glass
A high-strength quartz glass crucible having a crystallized glass layer (12) formed on the outer surface of (11). 2. The high-strength quartz glass crucible according to claim 1, wherein the crystallized glass layer (12) is formed on the entire outer surface of the crucible body (11). 3. A high-strength quartz glass crucible according to claim 1, wherein a plurality of crystallized glass layers (12) are formed on the outer peripheral surface of the crucible body (11) at intervals in the vertical direction. 4. A crucible body made of amorphous quartz glass
(11) A method for producing a high-strength quartz glass crucible in which an oxyhydrogen flame (21) is sprayed on the outer surface in an oxygen atmosphere to form a crystallized glass layer on the outer surface. 5. A crucible body made of amorphous quartz glass
(11) A carbon reinforcing material (26, 27) on its inner and outer surfaces
A high-strength quartz glass crucible for forming a crystallized glass layer on the outer surface of the crucible body (11) by heat-treating the reinforced crucible body (11) at a temperature of 1500 to 1600 ° C. in an oxygen atmosphere. Manufacturing method.