JPH10316440A - Production device of silica glass crucible - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for producing a highly pure crucible, hardly having minute bubble aggregation in the surface layer of the crucible by forming two or more independent holes for ventilation in a lid body covering the opening part of a rotatable upper-opening mold. SOLUTION: This device comprises a lid body 5 for covering the opening part of a rotatable upper-opening mold and having two or more independent first and second holes 6 and 7, a heating means 4 inserted from one of the holes, a means for charging silicon dioxide powder, and a rotationally driving structure 2 for rotating the upper-opening mold 1. The device can stably carry out the growth of silicon regulated so that the concentration of impurities in the silica glass crucible can be maintained at the concentration of the impurities in a raw material, and the silica glass crucible may contain <=0.5 ppb of copper element, chromium element and nickel element, <=120 ppb of iron element and <=20 ppb sodium element. Especially, the device can produce the crucible having a transparent layer in the depth of <=1 mm from the surface of the crucible, including <=1 of the number of minute bubble aggregations having >=2 mm largeness, having smooth inner surface and capable of producing a high quality silicon single crystal in a good crystallization rate.

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 having a high-purity inner surface layer and having no fine bubble aggregates.

[0002]

2. Description of the Related Art Conventionally, a silicon single crystal used as a substrate of a single crystal semiconductor material is manufactured by melting a silicon polycrystal in a quartz glass crucible and growing the same as a seed crystal by so-called Czochralski method. Has been manufactured. There are several types of quartz glass crucibles used in the above manufacturing method depending on the manufacturing method, but practically, silicon dioxide powder is filled along the inner peripheral surface of a rotatable hollow mold, and the mold is rotated. A translucent quartz glass crucible obtained by a method for producing a quartz glass crucible in which silicon dioxide powder is heated and melted while being heated has been used. The translucent quartz glass crucible has an advantage that a large number of bubbles are dispersed to make the heat distribution uniform, and that the crucible of any size can be manufactured because of its higher strength than other crucibles.

[0003] Even when a silicon single crystal is grown using the above-mentioned translucent quartz glass crucible, there is a problem that crystallization is unstable in the process and the crystallization ratio (the ratio of polycrystal to single crystal) decreases. Was. One of the reasons is that the sublimation component of silicon dioxide, which is the raw material, condenses and falls, and the microbubble aggregates formed by the thermal expansion cause partial peeling of the inner peripheral surface. And the like. In order to solve the above problem, a quartz glass crucible having a thick transparent layer formed by heating and melting the inner surface of the crucible to form a transparent layer or by scattering molten silicon dioxide powder has been proposed. None of the methods could sufficiently remove the microbubble aggregates, and could not pull up the silicon single crystal with a good crystallization rate. Further, in the heating and melting step, the inner surface of the obtained crucible is contaminated by selective evaporation and condensation of silicon dioxide and trace impurities contained therein, and scattering of ash accompanying consumption of the electrode graphite, resulting in high purity. Even with the use of raw materials, it was not possible to create a corresponding inner surface. For this reason, even if high-purity raw materials are used,
A sufficient effect for suppressing crystal defects was not obtained.

[0004]

In view of the current situation,
As a result of intensive studies, the present inventors have found that the above problems can be solved by ventilation of a high-temperature gas atmosphere containing silicon dioxide sublimation components and concentrated impurities in the mold, and have completed the present invention. . Ie

An object of the present invention is to provide an apparatus for producing a quartz glass crucible having a high purity without the presence of fine bubble aggregates in the inner surface layer.

Another object of the present invention is to provide an apparatus for manufacturing a quartz glass crucible capable of pulling a silicon single crystal at a high crystallization rate.

[0007]

The present invention to achieve the above object comprises a rotatable upper opening die, a rotary drive mechanism, a silicon dioxide powder supply means, a heating means, a lid for covering the opening of the die, and the like. Quartz glass crucible manufacturing equipment,
The present invention relates to an apparatus for manufacturing a quartz glass crucible, wherein the lid has two or more independent ventilation holes.

The quartz glass crucible obtained by the manufacturing apparatus of the present invention is a translucent quartz glass crucible, and the impurity concentration contained in the quartz glass crucible maintains a concentration corresponding to the impurity concentration of the raw material. , The concentration of each of the chromium element and the nickel element is 0.5 ppb or less, and the concentration of the iron element is 120
The silicon single crystal can be stably grown at a ppb or less and a sodium element concentration of 20 ppb or less. In particular, the transparent layer has a transparent layer at a depth of 1 mm or less from the inner surface of the crucible, and the transparent layer has no more than one microbubble aggregate of 2 mm or more. A single crystal can be manufactured with a high crystallization rate.

The quartz glass crucible is made of a highly purified crystalline silicon dioxide powder or a silicon dioxide powder such as a high purity amorphous silicon dioxide powder synthesized by a sol-gel method or the like. It is manufactured by supplying into a mold, forming a silicon dioxide powder-filled layer along the inner peripheral surface of the mold, and then heating and melting it from the inside, while ventilating the high-temperature gas atmosphere in the mold. In particular, a quartz glass crucible having a transparent layer is (i) provided with a vent hole in an upper opening type to make the gas permeable, and heat-melts the gas in the silicon dioxide powder packed layer from the outer periphery through this vent hole while reducing the pressure of the gas. And at the same time, a method of manufacturing a quartz glass crucible for ventilating a high-temperature gas atmosphere in a mold, and (ii) Japanese Patent Laid-Open No. 2-1.
As described in Japanese Patent No. 88489, etc., a silicon dioxide powder-filled layer is formed in a rotating upper opening mold, which is heated and melted from the inside of the mold to form a dough layer, and at the same time, silicon dioxide powder is supplied little by little and melted. -Manufactured by a method of manufacturing a quartz glass crucible that ventilates the high-temperature gas atmosphere in the mold while scattering. As the air flow used for ventilation in the mold in the above-mentioned production method, a gas having a dust amount of 0.01 mg / m ³ or less is used. If the amount of dust exceeds the above range, microbubbles may be formed on the inner surface of the crucible or contamination may occur due to the mixed impurity particles.

[0010] Ventilation taken during the manufacture of the quartz glass crucible is performed through holes formed in a lid covering the upper opening mold. The number of holes is two or more for exhaust and air supply.
The number is selected so that the high-temperature gas atmosphere in the mold is not destroyed. The holes are provided independently of each other, and have a circular, elliptical, or square shape, and a slit shape is not preferable because the ventilation action is weak. Through at least one of said holes,
The hot gas atmosphere containing the silicon dioxide sublimation component in the mold and the impurities concentrated by the repetition of sublimation and condensation is exhausted, and the corresponding airflow is supplied from other holes. Ventilation may be natural ventilation or forced ventilation, preferably forced ventilation. A ventilation duct is used for the forced ventilation, and the ventilation duct is provided above the exhaust hole, or is provided above the exhaust hole and the air supply hole to forcibly ventilate. If a dust filter is further connected to the end of the air supply duct provided for air supply, contamination of impurity particles in the outside air can be prevented, and the amount of dust in the atmosphere of the crucible production room can be reduced to 0.01 mg / m. Even if it exceeds ³ , the amount of dust in the atmosphere in the mold can be maintained at 0.01 mg / m ³ or less.

An apparatus for manufacturing a quartz glass crucible according to the present invention comprises:
As shown in FIG. 1, an upper opening mold 1 covers the mold opening 2
A lid 5 having at least one independent hole 6, 7; a heating means 4 inserted from one of the holes; a silicon dioxide powder supply means (not shown); Consists of In the manufacturing apparatus, in particular, the mold 1 is provided with an air hole 14 as shown in FIG. 2 so as to be gas permeable, and a vacuum device 13 is installed on the outer periphery. Or a device for forming a transparent layer on the inner surface by suction under reduced pressure, or as shown in FIG. 3, the heating means 4 and the silicon dioxide powder supply means 9 are inserted into the first hole 6 with a gap provided therebetween. 9
After forming the silicon dioxide powder-filled layer by heating, the silicon dioxide powder-filled layer is heated and melted, and at the same time, an additional silicon dioxide powder is supplied and melted and scattered to form a transparent layer 8. This is suitable because a quartz glass crucible having a high purity at a depth of 1 mm or less from the inner surface and having a transparent layer without a fine bubble aggregate and having a smooth inner surface can be produced. If the exhaust duct 10 shown in FIG. 3 is provided above the exhaust hole in each of the above-mentioned manufacturing apparatuses, ventilation is forcibly performed, which helps to improve the purity of the inner surface layer of the crucible and reduce the fine bubble aggregate.

When the exhaust duct 10 and the air supply duct 11 are additionally provided in each of the above manufacturing apparatuses as shown in FIG.
The ventilation of the high-temperature gas atmosphere in the mold is strongly promoted, and the formation and contamination of fine bubble aggregates on the inner surface of the quartz glass crucible are further reduced. If a dust filter 12 is connected to the end of the air supply duct 11, contamination of impurity particles can be prevented.

[0013]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Example 1 Using a device shown in FIG.
12 kg of 300 μm silicon dioxide powder was supplied, a silicon dioxide powder packed layer was formed along the inner peripheral surface of the mold, and the silicon dioxide powder packed layer was heated and melted from the inner surface while rotating the mold. While the high-temperature gas atmosphere in the mold is evacuated through the hole 7, a semi-transparent quartz glass crucible having a diameter of 460 mm is placed in the first hole 6 while supplying airflow and ventilating.
0 were created. The obtained quartz glass crucible was visually inspected, and the number of fine bubble aggregates having a diameter exceeding 2 mm was measured. Table 1 shows the results.

Further, 6 inch (152.4 mm) doped with boron using the quartz glass crucible prepared as described above.
Was pulled up. The presence or absence of dislocations at that time was observed for each pulling cycle. Table 2 shows the results.

Comparative Example 1 Ten silica glass crucibles were prepared using the same silicon dioxide powder as the raw material of Example 1 and the same operation as in Example 1 using the apparatus shown in FIG. . The same inspection as in Example 1 was performed on the obtained quartz glass crucible. The results are shown in Tables 1 and 2.

[0017]

[Table 1]

[0018]

[Table 2]

As is clear from the above Tables 1 and 2, the quartz glass crucible of the present invention contains almost no fine bubble aggregates, and even if a silicon single crystal is pulled up five times using the quartz glass crucible. There was little trouble and the single crystallization rate was good.

Example 2 The apparatus shown in FIG.
12 kg of 300 μm silicon dioxide powder was supplied to form a silicon dioxide powder packed layer, which was heated from the inner surface with a heating carbon electrode to form a dough layer, and 1.2 kg of silicon dioxide powder having the same particle size as above. Is supplied at a supply rate of 120 g / min, melted and scattered, and has a thickness of 0.8 mm.
Ten translucent quartz glass crucibles having a diameter of 460 mm and having a transparent layer were prepared. 1.2 g of the silicon dioxide powder
During the supply of kg, the gas was exhausted from the second hole 7 of the lid 5 through an exhaust duct at 14 m ³ / min. At that time, the amount of dust in the atmosphere of the production room was 0.005 mg / m ³ . The measurement of the amount of dust was performed by attaching a filter having an opening diameter of 0.8 μm to a low volume air sampler.

The resulting quartz glass crucible having a transparent layer was visually inspected, and the number of microbubble aggregates having a diameter exceeding 2 mm was measured. Table 3 shows the results.

Further, five samples are randomly selected from each of the ten quartz glass crucibles, and samples are cut out from the transparent layer and the fabric layer, and the amount of impurities in the samples is determined by high frequency inductively coupled plasma mass spectrometry. The measurement was performed in combination with the atomic absorption method. Table 4 shows the results.

On the other hand, for comparison, ten quartz glass crucibles having a transparent layer having a diameter of 460 mm were prepared using the lid of the apparatus of Example 2 as a lid without holes. A test similar to the above was performed on the obtained quartz glass crucible, and the results are shown in Tables 3 and 4.

[0024]

[Table 3]

[0025]

[Table 4]

As is clear from Tables 3 and 4, the quartz glass crucible of the present invention contains only an impurity amount corresponding to the impurity amount of the raw material in the transparent layer and the fabric layer, and the fine bubble aggregate also contains one. I could only find an individual.
On the other hand, in the transparent layer of the quartz glass crucible of the comparative example, many impurities were concentrated, and many fine bubble aggregates were also observed.

Example 3 A 6-inch (152.4 mm) silicon single crystal doped with phosphorus was pulled up using the remaining five pieces produced in Example 2. At that time, the presence or absence of dislocation was observed for each pulling operation. Table 5 shows the results. In addition, the number of oxidation-induced stacking faults per unit area in the central portion of the silicon single crystal obtained by the third pulling in Table 5 was examined, and the average value was obtained. Table 6 shows the results.

On the other hand, the other five quartz glass crucibles prepared for comparison in Example 2 were subjected to the same test as described above. Tables 5 and 6 show the results.

[0029]

[Table 5]

[0030]

[Table 6]

As is clear from Tables 5 and 6, when the quartz glass crucible of the present invention is used, a silicon single crystal can be stably pulled a plurality of times with a good crystallization rate, and the obtained silicon single crystal has a high crystallinity. It was of quality.

[0032]

In the apparatus for manufacturing a quartz glass crucible according to the present invention, no fine bubble aggregates are formed on the inner surface layer, and the impurity concentration, especially the transition metal concentration of alkali metal elements, calcium, iron, etc., is determined by the impurity in the raw material. A quartz glass crucible having a concentration commensurate with the concentration can be manufactured, and a silicon single crystal can be stably pulled using the quartz glass crucible. In addition, a crystallization rate is good, and a high-quality single crystal with high productivity can be manufactured.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an apparatus for manufacturing a quartz glass crucible showing an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of an apparatus for manufacturing a quartz glass crucible showing a preferred embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of an apparatus for manufacturing a quartz glass crucible showing another preferred embodiment of the present invention.

FIG. 4 is a longitudinal sectional view in which an exhaust duct and an air supply duct are provided in the quartz glass crucible manufacturing apparatus of FIG.

FIG. 5 is a longitudinal sectional view of a manufacturing apparatus of a quartz glass crucible without two or more holes in a lid in the apparatus of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Top opening type 2 Rotation drive mechanism 3 Silicon dioxide powder filling layer 4 Heating means 5 Lid 6 First hole 7 Second hole 8 Transparent layer 9 Silicon dioxide supply means 10 Exhaust duct 11 Air supply duct 12 Dust removal Filter 13 Vacuum device 14 Vent

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Watanabe 2-13-60 Kitafu, Takefu-shi, Fukui Prefecture

Claims (6)

[Claims] 1. A quartz glass crucible manufacturing apparatus provided with a rotatable upper opening die, a rotation drive mechanism, a silicon dioxide powder supply means, a heating means, and a lid covering an opening of the die. An apparatus for manufacturing a quartz glass crucible, having at least one independent ventilation hole. 2. A quartz glass crucible manufacturing apparatus provided with a rotatable gas-permeable upper opening mold, a rotation driving mechanism, a silicon dioxide powder supply means, a heating means, a lid covering an opening of the mold, and a vacuum device. An apparatus for manufacturing a quartz glass crucible, wherein the lid has two or more independent ventilation holes. 3. The quartz glass crucible according to claim 1, wherein a silicon dioxide powder supply means and a heating means are inserted with a gap in one of two or more independent ventilation holes. Manufacturing equipment. 4. The apparatus for manufacturing a quartz glass crucible according to claim 1, wherein exhaust means is provided in at least one of two or more independent ventilation holes of the lid. 5. The apparatus for manufacturing a quartz glass crucible according to claim 1, wherein an exhaust means and an air supply means are provided in two or more independent ventilation holes of the lid. 6. The apparatus for manufacturing a quartz glass crucible according to claim 5, wherein a filter for dust removal is connected to a tip of the air supply means.