JP3113461B2 - Quartz glass crucible manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for manufacturing a quartz glass crucible used for pulling a Si single crystal.

[0002]

2. Description of the Related Art A quartz glass crucible is arranged inside a graphite crucible and used for pulling a Si single crystal.

[0003] Quartz glass crucibles are produced by molding and melting quartz powder and then removing part of the unmelted powder attached to the outer surface of the crucible. Conventionally, unmelted powder adhering to the outer surface is removed by blasting the entire outer surface of the quartz glass crucible with high-pressure liquid as necessary, or by processing only the outer surface of the cylindrical portion (straight portion) of the crucible with a lathe or the like doing.

[0004]

However, in the former method, the center line average roughness of the outer surface of the quartz glass crucible is 1%.
Thus, the dimensional accuracy was not sufficient. On the other hand, the surface of the graphite crucible is finished by high precision machining. Due to such differences in surface roughness and dimensional accuracy, non-uniform gaps are often generated at the joint surfaces of the two.

For this reason, when pulling a Si single crystal, the quartz glass crucible softened due to high temperature is deformed and melted.
Vibration sometimes occurred on the liquid level i. In that case, the pulled Si single crystal was adversely affected, and the yield was reduced.

In the latter method, although the dimensional accuracy of the straight portion (cylindrical portion) is sufficient, a gap is also formed between the straight portion (cylindrical portion) and the graphite crucible in other portions, and similar liquid level vibration may occur. was there. Further, since the difference in surface roughness between the straight portion and the other portion is large, the heat ray transmittance in both portions is different during heating, which adversely affects the temperature control of the molten Si.

In any case, the above-mentioned problem tends to occur particularly in a large-diameter quartz glass crucible, and the yield (single crystallization ratio) of pulling a Si single crystal has been lowered.

An object of the present invention is to provide a method of manufacturing an opaque quartz glass crucible capable of improving the yield of pulling a Si single crystal by solving the above-mentioned problems of the prior art.

[0009]

According to the present invention, there is provided a crucible supporting / rotating means 20 for supporting the inner surface of an inverted crucible and rotating the crucible 1 at a low speed around a central axis, and keeping the rotating shaft vertical. Grinding wheel rotation moving means 21 for moving the grinding wheel 16 along the outside of the crucible 1 while rotating the grinding wheel 16 at high speed
Wherein the grinding wheel 16 has at least lower rounded grinding surfaces 18a and 19a, and the entire outer surface of the crucible 1 can be ground by the grinding wheel 16. The gist is a manufacturing device.

[0010]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a view schematically showing a preferred embodiment of a quartz glass crucible manufacturing apparatus according to the present invention, and FIG. 2 is a sectional view showing the grinding wheel of FIG. In this specification, opacity is interpreted in a broad sense, and translucency is also included in opacity. Similarly, grinding is interpreted broadly, and polishing is also included in grinding.

The crucible manufacturing apparatus 10 is an apparatus for grinding the entire outer surface of the crucible and removing the fused quartz powder adhering thereto. The quartz glass crucible set in the grinding apparatus of FIG. 1 is obtained by melting and molding quartz powder by a normal rotation melting method. As a result, an opaque quartz glass crucible including a large number of small bubbles is formed. A transparent layer is formed on the inner surface of the quartz glass crucible. Unmelted quartz powder adheres to the outer surface.

The crucible manufacturing apparatus 10 has a crucible supporting / rotating means 20 for supporting the inner surface of the crucible 1 in an inverted state and rotating the crucible 1 around a central axis at a low speed.
The crucible supporting and rotating means 20 includes a disk-type rotating table 12 set on a base 11. The rotary table 12 is provided with a center presser 15 on an extension of the rotary shaft. A rubber member 15a which is in contact with the center of the crucible bottom is fixed to the end of the center presser 15.

A straight portion upper chuck 13 is fixed in the middle of the center presser. The diameter of the straight portion upper chuck 13 can be changed in accordance with the size of the crucible, and a rubber member 13a which is in contact with the inner periphery of the straight portion of the crucible is disposed at the outer end.

A straight section lower chuck 14 is disposed above the rotary table 12. The diameter of the straight portion lower chuck 14 can also be changed according to the size of the crucible, and a rubber member 14a that is in contact with the inner periphery of the straight portion of the crucible is disposed at the outer end.

The crucible manufacturing apparatus 11 includes a grinding wheel rotating / moving means 2 for moving a grinding (grinding) wheel 16 along a crucible outer periphery while rotating the rotating shaft vertically at a high speed.
1 is provided. The grinding wheel rotation moving means 21 has a spindle that can rotate at high speed, and can set the grinding wheel 16.

The grindstone rotating / moving means 21 is movably disposed on a column (not shown) and can move at different speeds along paths (A to E) defined in the plane of FIG.
In the paths A and B, the spindle is moved at a grinding speed (low speed), and in the paths C to F, the spindle is moved at a rapid traverse.

In one preferred example, the grinding wheel 16 is
As shown in FIG. 2, it is a cup-shaped diamond grindstone. The grinding wheel 16 has a cup-shaped base metal 19 and a wheel mounting portion 17 which is detachably provided on the lower periphery.
The base metal 19 is made of aluminum, and the whetstone mounting portion 17 is made of resin. A grindstone main body 18 is attached to the grindstone mounting portion 17.

The grindstone main body 18 has a ground surface with a radius of curvature R, and has a semicircular cross section. Also,
As shown by the arrow in FIG. 2, the lower side may be a quarter circle. As described above, the grindstone main body 18 has at least a rounded ground surface on the lower side. Therefore, the amount of correction of the grindstone with respect to the work is always substantially constant, so that accurate grinding can be performed. The entire outer surface of the quartz glass crucible is more quickly and more appropriately represented by the following center line average roughness R:
In order to make the range of a, and to make the whole apparatus more compact, it is preferable that R is 3 to 35 mm.

The crucible 1 was rotated at a low speed by using the grinding device 10, while the paths A and B were moved while the grinding wheel 16 was rotated at a high speed to grind the entire outer surface of the crucible. Then, the center line average roughness Ra of the outer surface of the obtained quartz glass crucible was measured to be 0.1 μm to 50 μm.
Was within the range.

When the dimensional accuracy was examined, the error of the outer diameter was within ± 1 mm with respect to the design dimension of 508 mm, the thickness was also within ± 1.5 mm with respect to 11 mm.
The outer R shape has an error within ± 1 mm for 508 mm,
The height was within ± 2 mm with respect to 356 mm.

Using this quartz glass crucible, a Si single crystal was pulled, and the yield was examined. As a result, the yield was improved by about 5% as compared with the case where the conventional crucible was used.

[0022]

The apparatus for manufacturing a quartz glass crucible according to the present invention is provided with a crucible supporting / rotating means 20 for supporting the inner surface of the crucible in an inverted state and rotating the crucible 1 around the central axis at a low speed. A grinding wheel rotation moving means 21 for moving the grinding wheel 16 along the outer periphery of the crucible 1 while rotating the grinding wheel 16 kept at a high speed is provided, and the grinding wheel 16 has at least a rounded grinding surface 18a, 19a on the lower side. Since the entire outer surface of the crucible 1 is ground by the grinding wheel 16, the quartz glass crucible manufactured by the apparatus of the present invention has improved surface roughness and improved dimensional accuracy as compared with the conventional crucible.

Therefore, it is possible to maintain good contact with the carbon crucible disposed outside, and to prevent vibration of the molten Si liquid surface due to softening of the crucible.

Further, since the surface roughness of the straight portion and the bottom portion are substantially the same and the heat ray transmittance is equal, the accuracy of temperature control can be improved.

Therefore, by using the quartz glass crucible of the present invention, the yield of Si single crystal can be greatly improved as compared with the conventional crucible.

The present invention is not limited to the above embodiment. For example, the grinding path may be in the opposite direction of the path shown in FIG.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a quartz glass crucible manufacturing apparatus of the present invention.

FIG. 2 is a sectional view showing the grinding wheel of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Quartz glass crucible 10 Crucible manufacturing apparatus 11 Base 12 Rotary table 13 Straight part upper chuck 14 Straight part lower chuck 15 Center presser 13a, 14a, 15a Rubber member 16 Grinding grindstone 17 Grinding stone attaching member 18 Grinding stone main body 20 Crucible supporting rotating means 21 Grinding stone Rotary moving means

Continued on the front page (72) Inventor Naoe Ito 378, Oguni-machi, Oguni-machi, Oguni-machi, Nishiokitama-gun, Yamagata Prefecture Inside the Oguni Plant, Toshiba Ceramics Co., Ltd. Ground Toshiba Ceramics Co., Ltd.Oguni Factory (72) Inventor Yoshikazu Yokobori 30 Soya, Hadano-shi, Kanagawa Prefecture Toshiba Ceramics Co., Ltd. (56) References JP-U 62-162267 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) C03B 20/00 C30B 15/10 B24B 11 / 00-19/28

Claims (1)

(57) [Claims] A crucible supporting / rotating means (20) for supporting an inner surface of a crucible in an inverted state and rotating the crucible (1) at a low speed around a central axis is provided, and a grinding wheel (16) having a vertical rotating shaft. ) Is provided at a high speed while moving the crucible (1) along the outside of the crucible (1). The grinding wheel (16) is provided with a grinding surface (18a, 19a) having at least a rounded bottom. Crucible (1)
An apparatus for manufacturing a quartz glass crucible, characterized in that the whole outer surface of the quartz glass crucible can be ground with a grinding wheel (16).