JPH1025186A - Hollow mold for producing quartz crucible - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hollow mold for producing a quartz crucible, capable of efficiently removing inner foams in the wall body of the produced quartz crucible without being cracked even if the hollow mold is made into a two- division type hollow mold separated into an upper mold and a lower mold. SOLUTION: This hollow mold for producing a quartz crucible is obtained by forming an upper mold 14 having an upper part-connecting step part wall 18 at the bottom and a lower mold 16 having a lower part connecting part wall 20 at the top, respectively and linking the upper part-connecting step part wall 18 to the lower part-connecting step part wall 20 to bond an upper mold 14 to a lower mold 16. The upper part-connecting step part wall is linked through a connecting pin to the lower part-connecting step part wall to link the upper mold to the lower mold.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hollow mold for producing a quartz crucible, and more particularly to a hollow mold used for producing a quartz crucible used for pulling a single crystal semiconductor material, for example, a silicon single crystal.

[0002]

2. Related Art A method called the Czochralski method (CZ method) is widely used for manufacturing a single crystal semiconductor material, for example, a silicon single crystal. In this method, polycrystalline silicon is melted in a container, and the end of the seed crystal is immersed in the melting bath and pulled up while rotating. A single crystal having the same crystal orientation as the seed crystal grows on the seed crystal. . A quartz crucible is generally used for the container for pulling the single crystal.

[0003] In order to manufacture this quartz crucible, a quartz powder is put into a rotatable hollow mold, and the quartz powder is heated and melted by a heating means such as an arc discharge means while rotating the hollow mold. There is known a method in which a fused or semi-molten quartz powder layer is pressed against the inner peripheral surface of a hollow mold and sintered into a crucible shape by the action of.

In recent years, the diameter of a silicon single crystal to be pulled is increasing, and at the same time, the diameter of a quartz crucible and a hollow mold for producing a quartz crucible are also increasing. The difficulty of processing large-diameter hollow molds is significantly increased compared to small-diameter hollow molds. In addition, the upper surface of the hollow mold is easily oxidized and consumed by heat.However, when manufacturing large-diameter quartz crucibles, the amount of heat exposed to melting of quartz powder increases, and the manufacturing time increases,
Consumption of the upper surface of the hollow mold is further promoted. As a result, there is a disadvantage that the frequency of replacing the entire hollow mold increases, and the manufacturing cost increases accordingly.

When the quartz powder is being melted, a temperature difference is generated in the hollow straight body from the inner surface to the outer surface. When the inner surface is about 1000 ° C., the outer surface is estimated to be several hundred degrees Celsius. When such a temperature difference occurs, a strong tensile stress is generated on the outer surface of the hollow mold, so that the outer surface is easily cracked. When the hollow mold is divided into an upper mold and a lower mold and both are joined by a screwing method (for example, Japanese Patent Application Laid-Open No. 1-157426), a strong stress is locally generated at a screw joint, and the part is cracked. There is a problem that occurs.

On the other hand, many bubbles remain inside the wall of the quartz crucible manufactured by the above method. If there are many bubbles in the wall of the quartz crucible, the strength of the crucible is reduced.In addition, when the quartz crucible is heated, bubbles near the inner peripheral surface of the crucible thermally expand to partially peel off the inner peripheral surface, and the separated quartz is removed. There was a problem that the small pieces were mixed into the molten silicon to lower the single crystallization ratio.

Therefore, a quartz crucible having few internal bubbles is required, and as a method of producing the quartz crucible, a method of heating and melting a quartz powder filled in a hollow mold under reduced pressure has been known (Japanese Patent Publication No. Sho.
9-34659). However, even with this method, it has been difficult to completely remove bubbles inside the wall of the quartz crucible. After that, various proposals have been made to remove the above-mentioned internal bubbles, but none of them has obtained satisfactory results.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and does not crack even if it is divided into an upper mold and a lower mold. An object of the present invention is to provide a hollow mold for producing a quartz crucible capable of efficiently removing bubbles inside a crucible wall.

[0009]

In order to solve the above-mentioned problems, a first hollow mold for manufacturing a quartz crucible according to the present invention comprises an upper mold having an upper joint step wall at a lower part and a lower joint step wall at an upper part. And a lower mold having a lower mold and a lower mold, respectively, and joining the upper mold step and the lower joint step wall to join the upper mold and the lower mold. The upper mold and the lower mold are joined by joining the step wall and the lower joining step wall via joining pins.

In a second hollow mold for manufacturing a quartz crucible according to the present invention, an upper mold having an upper joint step wall at a lower part and a lower mold having a lower joint step wall at an upper part are formed respectively. In a hollow crucible for manufacturing a quartz crucible in which the upper mold and the lower mold are joined by joining the inner wall and the lower joint step wall, the hollow mold is located inside the upper joint step wall or the lower joint step wall. A blind hole on the outer surface side of the joining step wall to be
A through hole corresponding to the blind hole is formed in a joint wall located on the outside, and the upper mold and the lower mold are joined by inserting a joint pin into the through hole and the blind hole. And

A female screw portion is provided on the inner peripheral surface of the outer portion of the through hole, and a pin cover member having a male screw portion formed on the outer peripheral surface thereof is screwed into the female screw portion to be inserted into the through hole and the blind hole. The fixed joining pin can be easily fixed and its falling-off is completely prevented.

When the diameter of the blind hole and the diameter of the through hole are the same, and the diameter of the female screw portion is larger than the diameter of the remaining through hole portion, the joining pin can be accurately inserted and the joined joint can be inserted. Pins are securely fixed.

A third hollow mold for manufacturing a quartz crucible according to the present invention comprises an upper mold having an upper joint step wall at a lower part and a lower mold having a lower joint step wall at an upper part. In a hollow crucible for manufacturing a quartz crucible in which the upper mold and the lower mold are joined by joining the inner wall and the lower joining step wall, the joining is performed such that the tip end of the joining pin projects to the outer surface. A pin is press-fitted and fixed in the blind hole, a receiving groove corresponding to the blind hole is formed in a joining wall located outside, and a tip end of the joining pin is fitted in the receiving groove to thereby form the upper mold and the lower mold. It is characterized by being joined to a mold.

The receiving groove has a groove width slightly larger than the diameter of the joining pin, is provided with a guide longitudinal groove partly open at one end, and communicates laterally from the other end of the guide longitudinal groove part. The guide pin is inserted from one end of the guide longitudinal groove and moved to the other end, and then the tip of the joint pin is inserted into the fitting horizontal groove. By moving the upper mold and / or the lower mold horizontally so as to fit into the upper mold and the lower mold, the upper mold and the lower mold can be securely joined and fixed by a simple operation. There are advantages that can be.

In the two-piece hollow mold, a permeable member provided so as to face the inner surface of the hollow mold, and one end connected to the permeable member and the other end connected to the outer peripheral surface of the hollow mold. By providing the suction passage formed in the hollow wall as described above, it is possible to efficiently remove bubbles inside the wall of the manufactured quartz crucible.

The air permeable member and the suction passage can be provided in both the upper mold and the lower mold. In this case, it is necessary to perform an operation for sealing leakage at a connection portion between the upper mold and the lower mold. There is. When the air-permeable member and the suction passage are provided only in the lower mold, the efficiency of removing air bubbles above the quartz crucible is somewhat reduced, but there is no suction passage at the connection between the upper mold and the lower mold, and the manufacturing is performed accordingly. There is an advantage that it becomes easy.

As the material forming the hollow mold, a carbonaceous material such as graphite or graphite is preferable.

[0018] A large number of the permeable members are uniformly arranged on the inner surface of the hollow mold. As a method of arranging the permeable members, it is efficient to arrange the permeable members so that the suction ranges of the permeable members do not intersect. In addition to arranging the permeable members at the grid-like intersections, From the viewpoint of efficiency, it is preferable to arrange the air-permeable members in a zigzag shape (zigzag shape).

As a material for forming the air-permeable member, a carbonaceous material such as graphite or graphite is preferable. The gas permeable member can be used as long as the gas is permeable,
It is necessary to have a gas permeability higher than that of the hollow mold, but a preferable gas permeability is 1 kgf on average.
/ Cm ² in the range of about ¹ to 10 m ² / s.

[0020]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a longitudinal sectional view showing an example of a hollow mold for producing a quartz crucible according to the present invention, and FIG.
FIG. 3 is an enlarged view of a portion B in FIG. 1 and FIG.
5 is a top view of the upper mold, FIG. 5 is a longitudinal sectional view of the upper mold, FIG. 6 is a top view of the lower mold, FIG. 7 is a longitudinal sectional view of the lower mold, FIG. 8 is a front view of the joining pin, and FIG. 10 is a front view of the pin cover member, and FIG. 11 is a side view of the pin cover member.

In FIG. 1, reference numeral 12 denotes a hollow mold for manufacturing a quartz crucible according to the present invention. The hollow mold 12 includes an upper mold 14 and a lower mold 16.

The upper mold 14 has a cylindrical wall 14a, and an upper joining step wall 18 is formed at the lower end thereof. The lower mold 16 has a cylindrical portion 16a having the same diameter as the cylindrical wall 14a of the upper mold 14, and a round bottom 16b provided continuously below the cylindrical portion 16a. A lower joint step wall 20 is formed at the upper end of the cylindrical wall 14a so as to be able to contact the upper joint step wall 18.

A blind hole 2 is formed on the outer surface of the upper joint step wall 18.
2 are drilled. The lower joining step wall 20 has a through hole 24 having the same diameter as the blind hole 22 at a position corresponding to the blind hole 22.
Are drilled. A female screw is formed on the inner peripheral surface of the outer portion of the through hole 24 to form a female screw portion 26. The diameter of the female screw portion 26 is larger than the diameter of the remaining through-hole portion 24a.

Reference numeral 28 denotes a round bar-shaped joining pin which is detachably inserted into the blind hole 22 and the through hole 24. Numeral 30 is a disk-shaped pin cover member having a male screw portion 32 formed on the outer peripheral surface thereof, and a driver groove 3 formed on its flat outer surface portion.
4 are drilled. The pin cover member 30 is provided in the through hole 2.
4 is detachably screwed to the female screw portion 26. By screwing the pin cover member 30 to the female screw portion 26, the joint pin 28 is prevented from falling off.

In the illustrated example described above, the upper joint step wall 18
Has been described in which the lower joint step wall 20 is located outside, the blind hole 22 is formed in the upper joint step wall 18, and the through hole 24 is formed in the lower joint step wall 20. However, conversely, the upper joint step wall is positioned outside and the lower joint step wall is positioned inside, a blind hole is formed in the lower joint step wall, and a through hole is formed in the upper joint step wall. It goes without saying that the upper mold and the lower mold can be similarly joined using the joining pins.

The above-mentioned hollow mold 12, in other words, the upper mold 14, the lower mold 16, the joining pin 28 and the pin cover member 30
Is preferably formed of a carbonaceous material such as graphite or graphite.

Reference numeral 36 denotes a breathable member provided so as to face the inner surface of the lower mold 16. The breathable member 36 is
A large number are uniformly arranged on the inner surface of the lower mold 16. As a method of arranging the air-permeable members 36, it is efficient to arrange the air-permeable members 36 so that the suction ranges of the air-permeable members 36 do not cross each other, and the air-permeable members 36 may be arranged at intersections in a lattice shape. However, from the viewpoint of suction efficiency, it is preferable to arrange the air-permeable members 36 in a zigzag shape (zigzag shape).

The permeable member 36 is formed of a permeable carbonaceous material such as graphite or graphite.
Reference numeral 38 denotes a suction passage formed in the wall of the lower mold 16. One end of the suction passage 38 is connected to the air permeable member 36, and the other end thereof communicates with the outer peripheral surface of the lower mold 16.

In the apparatus for manufacturing a quartz crucible provided with the hollow mold 12 described above, the hollow mold 12 is supported in a state where the outer surface is surrounded by a support frame. The hollow mold 12 is horizontally rotated by a rotation driving means. The outer periphery of the hollow mold 12 is connected to reduced-pressure suction means such as a vacuum pump, and the outer periphery is subjected to reduced-pressure suction. The inner surface of the hollow mold 12 is heated by a heating means, for example, an arc discharge means.

When a quartz crucible is manufactured using the quartz crucible manufacturing apparatus having the hollow mold 12, the raw quartz powder is first charged into the inner peripheral surface of the hollow mold 12 while rotating the hollow mold 12. I do. The quartz powder is pressed against the inner peripheral surface of the hollow mold 12 by the action of the centrifugal force of the rotating hollow mold 12 and is deposited along the inner peripheral surface to form a quartz powder layer.

Next, the quartz powder layer is heated and melted from the inner peripheral surface side thereof by a heating means such as an arc discharge means. Along with the heating and melting, the outer surface of the hollow mold 12, for example, the bottom outer surface is suctioned under reduced pressure by a vacuum suction means such as a vacuum pump, and the internal gas in the quartz powder layer is passed through the gas permeable member 36 and the suction passage 38. Suction and exhaust.

By the above-mentioned heating and melting, the quartz powder layer is gradually melted from the inner peripheral surface to the vicinity of the outer surface, and sintered in a crucible shape.

In the illustrated embodiment, the case where a large number of small disk-shaped members are independently disposed as the large number of air-permeable members 36 has been described.
In addition to using a triangular member, the hollow mold 12 can be used.
It is also possible to dispose a large number of annular or ring-shaped members which make a round around the inner peripheral surface of the member.

In the illustrated example, the structure in which the permeable material 36 and the suction passage 38 are provided only in the lower mold 16 is shown. However, the structure in which the permeable material 36 and the suction passage 38 are formed also in the upper mold 14 is adopted. Of course, it is possible.

Since the hollow mold 12 of the present invention is configured to be dividable into two parts by the upper mold 14 and the lower mold 16, the size of the carbon lump to be used can be small, the material can be easily obtained, and the production is easy. Therefore, the carbon material can be easily purified. Further, if the upper portion of the hollow mold is oxidized and consumed, the lower mold can be used as it is by replacing the upper mold, thereby reducing the cost.

When the upper mold 14 and the lower mold 16 are joined by using the joining pins 28 as in the two-part hollow mold 12 of the present invention, a tensile stress is applied to the outer surface of the straight body of the hollow mold 12. Even if cracks occur, the stress can be released by the clearance of the joining pin 28, and the crack of the hollow mold 12 can be avoided.

In the above example, the upper die 14 and the lower die 16
As a means for bonding and fixing, the configuration in which the joining pin 28 is inserted into the blind hole 22 and the through hole 24 and the pin cover member 30 is screwed to the female screw portion 26 of the through hole 24 has been described. The upper mold 14 and the lower mold 16 need only be joined and fixed. For example, joining means as shown in FIGS. 12 and 13 can be adopted. 12 and 13
, The same or similar members as in FIGS. 1 to 11 are denoted by the same reference numerals.

A blind hole 22 serving as a pin hole is formed on the outer surface of the upper joint wall 18 of the upper mold 14. The joining pin 28 is manufactured so as to be press fit into the blind hole 22. The proximal end of the joining pin 28 is pressed into the blind hole 22, and the joining pin 28 is pressed into and fixed to the blind hole 22 so that the distal end of the joining pin 28 projects outward.

An L-shaped receiving groove 25 is formed in the lower joining step wall 20 of the lower mold 16 at a position corresponding to the blind hole 22. The receiving groove 25 has a groove width slightly larger than the diameter of the joining pin 28 so that the joining pin 28 can be moved, and has a guide vertical groove 25a having an open upper end and a bottom portion of the guide vertical groove 25a. A fitting horizontal groove portion 25b provided to be communicated to the side and having substantially the same size as the diameter of the joining pin 28.
It is composed of

The outer end of the joining pin 28, which is press-fitted and fixed in the blind hole 22, is inserted into the guide vertical groove 25a from the upper end opening thereof to thereby form the guide vertical groove 2a.
5a. Then, the upper mold 1 is lowered so that the tip of the joining pin 28 fits into the fitting horizontal groove 25b.
4 and / or lower mold 16 is moved horizontally. As a result, the upper mold 14 and the lower mold 16 are joined and fixed. Further, when the upper mold 14 and the lower mold 16 are separated from each other, it is needless to say that the above procedure may be reversed.

In the examples of FIGS. 12 and 13, the upper joint step wall 18 is located inside and the lower joint step wall 20 is located outside. The case where the receiving groove 25 is formed in the step wall 20 has been described. But,
Conversely, the upper joint step wall may be located outside and the lower joint step wall may be located inside, a blind hole may be formed in the lower joint step wall, and a receiving groove may be formed in the upper joint step wall. Needless to say, the upper mold and the lower mold can be similarly joined. In this configuration, the receiving groove has an inverted L-shape, and the lower end of the guide vertical groove is of course open.

[0042]

As described above, the hollow mold for manufacturing a quartz crucible of the present invention is a two-part mold divided into an upper mold and a lower mold, and has an effect that cracks are effectively prevented. In addition, when a quartz crucible is manufactured using the quartz crucible manufacturing apparatus having the hollow mold according to the present invention, a great effect can be obtained in that bubbles inside the wall of the quartz crucible can be efficiently removed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of a hollow mold for manufacturing a quartz crucible according to the present invention.

FIG. 2 is an enlarged view of a portion A in FIG.

FIG. 3 is an enlarged view of an arrow B portion of FIG. 1;

FIG. 4 is a top view of the upper die.

FIG. 5 is a vertical sectional view of an upper die.

FIG. 6 is a top view of the lower die.

FIG. 7 is a vertical sectional view of a lower die.

FIG. 8 is a front view of a joining pin.

FIG. 9 is a side view of the joining pin.

FIG. 10 is a front view of the pin cover member.

FIG. 11 is a side view of the pin cover member.

FIG. 12 is a cross-sectional view illustrating a main part of another example of joining an upper mold and a lower mold.

FIG. 13 is a front view of FIG.

[Explanation of symbols]

 12 Hollow mold 14 Upper mold 14a Cylindrical wall 16 Lower mold 16a Cylindrical part 16b Bottom 18 Upper joint step wall 20 Lower joint step wall 22 Blind hole 24 Through hole 24a Through hole part 25 Receiving groove 26 Female screw part 28 Joint pin 30 Pin cover member 32 Male screw part 34 Groove part 36 Breathable member 38 Suction passage

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Tatsuhiro Sato 2-13-60 Kitafu, Takefu-shi, Fukui Prefecture Inside the Takefu Plant of Shin-Etsuishi Ei Co., Ltd. (72) Mitsuo Matsumura 2-13-60 Kitafu, Takefu-shi, Fukui Prefecture No. Shin-Etsuishi Ei Co., Ltd. Takefu Factory (72) Inventor Shigeo Mizuno 2--13-60 Kitafu, Takefu-shi, Fukui Prefecture Shin-Etsuishi Eiji Co., Ltd. Takefu Factory (72) Inventor Hiroyuki Watanabe 2--13 Kitafu, Takefu-shi, Fukui Prefecture No. 60 Shin-Etsuishi Ei Co., Ltd.

Claims (12)

[Claims] An upper mold having an upper joint step wall at a lower part and a lower mold having a lower joint step wall at an upper part are respectively formed, and the upper joint step wall and the lower joint step wall are joined. In the hollow mold for manufacturing a quartz crucible formed by joining the upper mold and the lower mold, the upper mold step and the lower joint step wall are joined to each other through joining pins. And a hollow mold for manufacturing a quartz crucible. 2. An upper mold having an upper joint step wall at a lower part and a lower mold having a lower joint step wall at an upper part are respectively formed, and the upper joint step wall and the lower joint step wall are joined. In the hollow crucible for manufacturing a quartz crucible formed by joining the upper mold and the lower mold, a blind hole is formed on the outer surface side of the joining step wall located inside the upper joining step wall or the lower joining step wall. The upper mold and the lower mold are joined by piercing, piercing a through hole corresponding to the blind hole in a joint wall located outside, and inserting a joining pin into the through hole and the blind hole. A hollow mold for manufacturing a quartz crucible, characterized in that: 3. A female screw portion is provided on an inner peripheral surface of an outer portion of the through hole, and a pin cover member having a male screw portion formed on an outer peripheral surface thereof is screwed to the female screw portion, and inserted into the through hole and the blind hole. 3. The hollow mold for manufacturing a quartz crucible according to claim 2, wherein the attached joining pin is prevented from falling off. 4. The quartz crucible according to claim 3, wherein the diameter of the blind hole is the same as the diameter of the through hole, and the diameter of the female screw portion is larger than the diameter of the remaining through hole portion. Hollow type. 5. An upper mold having an upper joint step wall at a lower part and a lower mold having a lower joint step wall at an upper part, respectively, and joining the upper joint step wall and the lower joint step wall. In the hollow mold for manufacturing a quartz crucible formed by joining the upper mold and the lower mold, the joining pin is press-fitted and fixed to the blind hole so that the tip end of the joining pin protrudes to the outer surface, and is outwardly fixed. A receiving groove corresponding to the blind hole is formed in the joint wall located, and the upper mold and the lower mold are joined by fitting a tip end of the joining pin into the receiving groove. Hollow type for quartz crucible production. 6. The guide groove having a groove width slightly larger than the diameter of the joining pin, and having a guide longitudinal groove partly open at one end and being provided to communicate laterally from the other end of the guide longitudinal groove part. It is composed of a mating horizontal groove that is approximately the same size as the pin diameter,
The distal end of the joining pin is inserted from one end of the guide vertical groove and moved to the other end, and then the upper mold and / or the lower mold are moved so that the distal end of the joining pin fits into the fitting horizontal groove. 6. The hollow mold for manufacturing a quartz crucible according to claim 5, wherein the upper mold and the lower mold are joined by being moved horizontally. 7. The hollow mold according to claim 1, wherein the air-permeable member is provided so as to face an inner surface of the hollow mold, and one end is connected to the air-permeable member and the other end is provided. And a suction passage formed inside the wall of the hollow mold so as to communicate with the outer peripheral surface of the hollow mold. 8. The hollow mold for manufacturing a quartz crucible according to claim 7, wherein the air-permeable member and the suction passage are provided only in the lower mold. 9. The hollow mold for manufacturing a quartz crucible according to claim 7, wherein the air-permeable member and the suction passage are provided in the lower mold and the upper mold. 10. The hollow mold for producing a quartz crucible according to claim 1, wherein the hollow mold is formed of a carbonaceous material. 11. The hollow body according to claim 7, wherein a plurality of said air-permeable members are uniformly arranged on the inner surface of said hollow mold.
The hollow mold for manufacturing a quartz crucible according to any one of the above items. 12. The air-permeable member is formed of an air-permeable carbonaceous material.
12. The hollow mold for manufacturing a quartz crucible according to any one of items 11 to 11.