JP2001261353A - Synthetic silica glass powder for quartz glass crucible, method for producing the same, and method for producing quartz glass crucible using synthetic silica glass powder - Google Patents

Abstract

(57) [Problem] To provide a synthetic quartz glass crucible that suppresses the generation of bubbles in the inner layer of the quartz glass crucible at the time of high-temperature heating and improves the crystallization rate (DF rate) of silicon single crystal while maintaining high purity. Realize. SOLUTION: An amorphous silica powder produced by a sol-gel method is heated to 800 to 1300 ° C. in a hydrogen atmosphere to produce a synthetic silica glass powder optimal for a quartz glass crucible for pulling a silicon single crystal. Also,
The obtained synthetic silica glass powder is formed into a quartz glass crucible by an arc melting method, and a quartz glass crucible having a high DF ratio is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic silica glass powder for a quartz glass crucible used for pulling a silicon single crystal and a method for producing the same, and further relates to a quartz using the synthetic silica glass powder. The present invention relates to a method for manufacturing a glass crucible, and particularly to a silicon single crystal pulling quartz capable of suppressing generation of bubbles at a high temperature on the inner surface of the crucible and improving a single crystallinity ratio (DF rate) of the manufactured silicon single crystal. The present invention relates to a method for manufacturing a glass crucible.

[0002]

2. Description of the Related Art Conventionally, a silicon single crystal has been manufactured by a method called the Czochralski method (CZ method). CZ
With the method, polysilicon is melted in a crucible made of quartz glass, a silicon single crystal seed crystal is immersed in this silicon melt, the seed crystal is gradually pulled up while rotating the crucible, and the silicon single crystal is This is a method of producing a single crystal by growing a seed crystal as a nucleus. In this method, it is of course an important factor that the silicon single crystal to be produced is of high purity, but at the same time, the production yield of silicon wafers produced from this silicon single crystal is directly affected by the DF rate. In addition, improving the DF rate has become a major issue. Based on these requirements in the CZ method, there is a strong demand for quartz glass crucibles, which are important members in the CZ method, to have higher purity and improved characteristics for improving the DF ratio.

Usually, a quartz glass crucible is manufactured by a method called an arc melting method. In this method, a crucible is filled with high-purity quartz powder, and the quartz powder is heated to a high temperature by arc discharge and melted to produce a crucible. In the crucible thus manufactured, the inner wall surface of the crucible is melted relatively smoothly and there is almost no air bubbles, and a transparent layer is formed.On the other hand, a relatively large number of air bubbles remain in the portion near the outer wall surface of the crucible wall. ing.

When such a crucible is used for pulling a silicon single crystal, a part of the inner wall surface of the crucible is dissolved in a silicon melt during the step of pulling a silicon single crystal.
If impurities are present on the inner surface of the crucible, they are diffused into the silicon melt, causing contamination of the silicon single crystal or generation of crystal defects. Also, bubbles were generated at the time of high-temperature heating near the inner wall surface of the quartz glass crucible that was transparent at the beginning of manufacturing, and this bubble grew during single crystal pulling work and burst or expanded the crucible, and this crucible was used. Of silicon single crystal in the silicon single crystal pulling process
It is considered to be a factor that lowers the F ratio. Under such circumstances, various improvements have been made to improve the purity of the quartz glass crucible and the DF ratio.

As one example, there is a technique disclosed in Japanese Patent No. 2863554. This relates to a double-layered quartz glass crucible in which an inner lining layer of synthetic silicon dioxide is formed inside the outer wall of the quartz glass crucible. Conventionally, in a crucible having a synthetic quartz inner lining layer, which is a known decomposition product of silicon tetrachloride, a silicon alkoxide is hydrolyzed in order to prevent foaming during use of the crucible due to a remaining decomposition product. To form an inner lining layer. According to this method, a quartz glass crucible that is smooth, dense, and can withstand high-temperature use can be obtained as the inner lining layer. However, it has not been able to sufficiently respond to recent demands for higher DF rate improvement.

Attempts have been made to use synthetic quartz particles as a crucible material in order to purify a quartz glass crucible with high purity (see Japanese Patent Application Laid-Open No. 4-154613).
For example, it is known to use amorphous synthetic quartz produced by hydrolyzing silicon tetrachloride as a crucible raw material,
Since amorphous synthetic quartz contains a large amount of hydroxyl groups, there has been a problem that the crucible produced therefrom has insufficient mechanical strength upon contact with a silicon melt. Therefore,
In order to remove hydroxyl groups in quartz glass that cause a decrease in mechanical strength at high temperatures, amorphous synthetic silica is converted into cristobalite to improve bulk density and purify. . However, in this method, a phase transition accelerator is used when cristobalite is formed, but it is difficult to remove this in a subsequent step, which causes a reduction in the efficiency of the manufacturing process (see JP-A-4-154613). . It is also conceivable to use the cristobalite powder for the inner layer of the two-layer crucible.When this cristobalite powder is used for the inner layer, a crucible having a high bulk density and a high purity is obtained, but the quartz glass crucible is depressurized. In the case of using for CZ below, the problem that the DF ratio is lowered due to the generation of bubbles in the inner layer portion or the expansion is not solved, and in the experiments of the present inventors, cristobalite powder was used. In such a case, in the crucible production stage, particularly, it was not possible to substantially eliminate bubbles in the inner surface layer.

It is also known to use quartz glass powder produced by a sol-gel method as a raw material in order to purify a quartz glass crucible with high purity (Japanese Patent No. 2684449).
No.). By the way, quartz glass powder produced by this sol-gel method can be easily purified, and has good crucible moldability by the arc melting method. However, when the silicon single crystal is pulled under reduced pressure, the crucible wall expands or deforms. Has been a problem. Therefore, conventionally, various production methods for reducing bubbles on the crucible wall surface have been improved, and as one of the methods, a quartz glass crucible is manufactured using a gas-permeable mold, and quartz particles are formed in the mold. During melting, a quartz glass layer having a bubble layer on the outer surface by forming a transparent quartz glass layer on the inner surface by depressurizing through an air-permeable mold in the first half of the melting process and stopping or weakening the depressurization in the latter half of the melting process Are known. In the synthetic quartz glass crucible manufactured using the synthetic powder on the inner surface side by the above-mentioned depressurization method, the synthetic layer is formed as a transparent layer. According to this method, bubbles on the inner surface of the crucible are apparently reduced.However, when these are used for pulling a silicon single crystal, when bubbles are generated by high-temperature heating in the inner synthetic transparent layer that was transparent before the pulling. However, there has been a problem that it has not been possible to meet recent demands for a high DF rate improvement.

Further, in order to reduce bubbles when the quartz glass crucible is heated at a high temperature, there is known a technique of setting a hydrogen gas atmosphere at the time of arc melting in the production of the quartz glass crucible (see Japanese Patent No. 2559604). However, when this technique is used for a lining synthetic quartz glass crucible having the above-mentioned two-layer structure, the hydroxyl group concentration in the inner layer of the crucible increases, the amount of erosion in CZ increases, and the service life becomes longer. At present, it has become impossible to obtain a sufficient DF ratio as a result of shortening or deformation of the crucible becoming large.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art relating to a quartz glass crucible, and is intended to maintain the purity of the quartz glass crucible while maintaining the purity of the quartz glass crucible at a high temperature. It is an object of the present invention to provide a quartz glass crucible that suppresses bubble generation and expansion and improves the DF ratio.

[0010]

Means for Solving the Problems In order to solve the above-mentioned problems of the present invention, the present inventor has conducted various studies. The focus is on the fact that it can be achieved.

That is, a first aspect of the present invention is an amorphous silica powder produced by a sol-gel method, which has a wave number of 2360 cm ⁻¹ and 2330 cm ⁻ in a transmittance spectrum measured by a Fourier transform infrared spectrophotometer. ^{No. 1} is a synthetic silica glass powder for a quartz glass crucible characterized by not exhibiting an absorption band, particularly having an average particle size of 150 to 350.
μm and a maximum particle size of 500 μm or less.

Further, the second present invention is characterized in that the amorphous silica powder produced by the sol-gel method is heat-treated at a temperature of 800 to 1300 ° C. in an atmosphere containing 10% by volume or more of hydrogen gas. A method for producing a synthetic silica glass powder for a quartz glass crucible, and in particular, the heat treatment temperature and the treatment time for obtaining the synthetic silica glass powder are set to a range in which the synthetic silica glass powder is not crystallized. It is characterized by the following.

Further, a third aspect of the present invention is to produce an amorphous silica powder produced by a sol-gel method by performing a heat treatment at a temperature of 800 ° C. to 1300 ° C. in an atmosphere containing 10% by volume or more of hydrogen gas. The synthetic silica glass powder substantially containing the synthetic silica glass powder as a main component is poured into a container-shaped mold to be formed into a crucible shape, and arc melting is performed while rotating the mold to produce a quartz glass crucible. Is the way.

[0014] In a fourth aspect of the present invention, a crystalline silica powder is charged into a container-shaped mold to form a crucible shape, and an amorphous silica powder produced by a sol-gel method is further placed inside the crucible at 800 ° C to 1300 ° C. A synthetic silica glass powder produced by performing a heat treatment in an atmosphere containing hydrogen gas at 10% by volume or more at a temperature of 100 ° C. is charged into a crucible having a predetermined thickness, and then the arc is melted while rotating the mold. A method for manufacturing a quartz glass crucible, comprising:

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the present invention provides a hydrogen-treated synthetic silica by performing a heat treatment by flowing hydrogen gas into a heat treatment furnace filled with amorphous silica powder produced by a sol-gel method. The present invention is to improve the DF ratio of a crucible manufactured by using glass powder. Hereinafter, such an embodiment of the present invention will be described in detail.

In the present invention, amorphous silica powder obtained by a sol-gel method is used as a synthetic silica glass powder raw material. Methods of producing amorphous silica powder by synthesis include hydrothermal synthesis, oxyhydrogen flame synthesis, and chlorine-free synthesis in addition to the sol-gel method. Ease of production, product purity, economy, etc. In this respect, the sol-gel method is most suitable. Further, in the present invention, the amorphous silica powder, in a transmittance spectrum measured by a Fourier transform infrared spectrophotometer (FT-IR),
It is a synthetic silica powder for quartz glass crucibles in which absorption bands at wave numbers of 2360 cm ^-1 and 2330 cm ^-1 are not recognized. Any absorption band at wavenumber 2360 cm ^-1 and 2330cm ^-1 in FT-IR, but is indicative of the presence of O = C = O bonds, the present inventors have found that amorphous silica obtained by a sol-gel process In the powder, use is made of a synthetic silica glass powder in which the above-mentioned bonding, which is considered to be caused by silicon alkoxide (eg, Si (OC ₂ H ₅ ) ₄ ) as a raw material, is not confirmed, particularly for forming a transparent layer on the inner surface of a quartz glass crucible. As a result, it was found that it is possible to further suppress the generation or expansion of bubbles in the inner surface transparent layer when pulling a silicon single crystal.

The particle size of the synthetic silica glass powder is preferably such that the average particle size is 150 to 350 μm and the maximum particle size is 500 μm or less. If the average particle size is below the above range, the crucible moldability will deteriorate, and the production yield of the crucible will decrease. On the other hand, if the average particle size exceeds the above range, bubbles are likely to remain in the inner layer of the side wall of the crucible obtained, and foaming (expansion) at the time of pulling the single crystal causes a decrease in DF ratio. If the maximum particle size exceeds the above range, the effect of the hydrogen treatment cannot be sufficiently obtained.

Next, the method for producing the synthetic silica glass powder of the present invention will be described. The above-mentioned synthetic silica glass powder is obtained by converting an amorphous silica powder produced by a sol-gel method to 800 ° C. to 13 ° C.
It can be obtained by performing heat treatment at a temperature of 00 ° C. in an atmosphere containing 10% by volume or more of hydrogen gas.

The hydrogen gas used in the present invention may be a pure hydrogen gas or a mixed gas. As the diluting gas, any gas that is non-reactive with hydrogen and silica glass can be used. From the viewpoint of economy and the like, a rare gas such as nitrogen gas and helium gas is suitable. It is desirable that the concentration of hydrogen in the mixed gas be 10% by volume or more.
When the hydrogen concentration is higher, the effect of suppressing the generation of bubbles is higher. When the hydrogen gas concentration is lower than 10% by volume, diffusion of hydrogen into the amorphous silica powder hardly occurs even if the treatment time is extended, The effect of suppressing bubble generation during high-temperature heating of the present invention cannot be expected.

The heating temperature during the hydrogen treatment in the present invention is as follows:
A range of 800 to 1300 ° C is desirable. Heating temperature is 80
When the temperature is lower than 0 ° C., the hydrogen gas diffusion effect does not occur, and it cannot be expected to suppress the generation of bubbles during high-temperature heating. When the heating temperature exceeds 1300 ° C., a hydrogen diffusion effect can be expected,
Amorphous silica powder is thermally fused, and must be reground and adjusted for particle size when used as a crucible material after hydrogen treatment, which not only increases the number of steps but also causes secondary contamination of the amorphous silica powder. Is more likely to occur, which is not preferable. As described above, the amorphous silica powder crystallizes, that is, it is difficult to eliminate bubbles on the surface of the crucible produced when the synthetic silica glass powder is cristobalite. It is necessary to carry out the hydrogen treatment under conditions that do not cause the above. In the case of the amorphous silica powder obtained by the sol-gel method, it has been found that cristobalite is formed by heating at 1600 ° C. for 10 hours or more at a high temperature for a long time. It is.

Since the hydrogen treatment time in the present invention depends on the particle size distribution of the powder to be treated and the heat treatment temperature, it cannot be said unconditionally, but is preferably in the range of about 30 minutes to 10 hours. When the particle size distribution of the powder to be treated is small and when the processing temperature is high, a short processing time is sufficient. On the other hand, when the particle size distribution is large and the processing temperature is low, a long processing time is required. If the heating time is short, the hydrogen diffusion effect cannot be expected and foaming during high temperature heating cannot be suppressed, and if the treatment time exceeds 10 hours, the synthetic silica glass powder may crystallize and transfer to cristobalite. Not only is it not only economical, but also the effect of improving properties is not exhibited, and it is not economical.

The synthetic silica glass powder hydrogen-treated by the above-mentioned method has no particle adhesion or crushing, and its particle size distribution is hardly different from the powder to be treated. In addition, the hydroxyl group concentration of the hydrogen-treated powder increases within 10% of that before the treatment, and it is generally considered that the higher the hydroxyl group concentration, the lower the viscosity at high temperature. The viscosity at high temperature of the quartz glass crucible manufactured as described above was not much different from the case of using raw material powder not subjected to hydrogen treatment.

In the hydrogen treatment of the amorphous silica powder of the present invention, since a combustible hydrogen gas is handled at a high temperature, it is preferable to use a heat treatment furnace which can be sealed so that the hydrogen gas does not leak outside. As such an apparatus, a powder storage container made of a quartz glass crucible filled with, for example, an amorphous silica powder to be treated in a heat treatment furnace, and the above-mentioned powder storage container for preventing secondary contamination from inside the furnace. It is possible to use a batch type apparatus equipped with a piping system for supplying an atmosphere gas such as a hydrogen gas or a shielding vessel to be covered, or a continuous heat treatment furnace / cyclone (registered trademark) type furnace equipped with similar components. .

As an example of a hydrogen processing apparatus that can be used in the present invention, a batch type apparatus shown in FIG. 1 will be described. In the figure, reference numeral 1 denotes a furnace housing the entire powder processing apparatus of the present invention, and a heater 11 is embedded in the furnace wall over the entire circumference. Various heat sources can be used as the heat source, but electric heating is preferable because it is the easiest to control.

The hearth 2 of the apparatus of the present invention is
Is detachably provided by being movable up and down. A hole 3 is formed in the center of the hearth 2. An air supply pipe 11 and an exhaust pipe 12 for supplying hydrogen gas and, if necessary, nitrogen gas are inserted through the hole 3. A quartz glass pedestal 4 is provided on the hearth 2. Holes corresponding to the holes 3 in the hearth 2 are also formed in the quartz glass pedestal, and supply / exhaust pipes are inserted in the same manner as the holes 3 in the center of the hearth.

On the quartz glass pedestal 4, a powder container 5 such as a quartz crucible for containing the amorphous silica powder to be treated is arranged. The powder storage container 5 is required to have high purity because the amorphous silica powder to be treated is stored and is in direct contact therewith, and it is desirable that the powder storage container 5 has the same purity as a quartz glass crucible for pulling a silicon single crystal. More preferably, it is made of quartz.

An air supply pipe 11 for introducing a processing gas is closely fitted in the center of the bottom of the powder container 5 so that at least the gas inlet is buried in the amorphous silica powder. It is preferable to arrange them in The reason for this is that simply introducing hydrogen gas into the space in the shielding container cannot efficiently and effectively hydrogen-treat the amorphous silica powder because hydrogen is lighter than other gases. Air supply piping 11
By bending the open end downward,
It is desirable to prevent the synthetic silica glass powder to be treated from entering. It is desirable that the end of the pipe opening downward is located as close as possible to the bottom of the powder container 5 so that the processing gas can reach all spaces of the powder container. A shielding container 6 is arranged to accommodate the quartz glass pedestal 4 and the quartz crucible 5. This shielding container 6 needs to be finished with high precision so as to keep the inside airtight in cooperation with the hearth 2 so as to prevent the processing gas inside from leaking out of the shielding container to the outside. Also,
The material of the shielding container 6 is quartz glass or SiC.
High-purity heat-resistant materials such as ceramics are suitable. Hydrogen gas that is introduced from the air supply pipe 11 and flows out without being diffused and absorbed by the synthetic silica glass powder is exhausted by the exhaust pipe 12 that is led out of the shielding container to the outside, and is treated outside the system by combustion or the like.

The synthetic silica glass powder obtained by hydrotreating the amorphous silica powder produced by the sol-gel method as described above is effective when used in any known method for producing a quartz glass crucible. A method of manufacturing a quartz glass crucible in which a crucible is put into a container-shaped mold, formed into a crucible shape, and arc-melted while rotating the mold is preferable. The silica glass powder substantially containing the above-mentioned synthetic silica glass powder as a main component refers to a case where this synthetic silica glass powder is 100% and other amorphous silica or crystalline silica such as quartz. It means that the content is 5.0 wt% or less of the whole. Further, as a method for producing a quartz glass crucible of the present invention, a crystalline silica powder is charged into a container-like mold to form a crucible shape, and further, an amorphous silica powder produced by a sol-gel method is heated to 800 ° C. ~ 1300 ℃
The synthetic silica glass powder produced by performing a heat treatment in an atmosphere containing hydrogen gas at 10% by volume or more at the temperature described above is charged and formed into a crucible shape having a predetermined thickness, and arc melting is performed while rotating the mold. Is more preferable.

According to this manufacturing method, the outer layer of the quartz glass crucible is formed from a melt of crystalline silica powder having a high viscosity at high temperature, so that the crucible as a whole has high deformation resistance, and at least quartz The synthetic silica glass powder obtained by hydrogenating the amorphous silica powder is placed on the inner surface of the glass crucible and melted.
The generation of bubbles in the inner transparent layer during pulling of the single crystal is suppressed.

[0030]

EXAMPLE First, the particles were produced by a commercially available sol-gel method and had a particle size distribution shown in Table 1 and an average particle size of 205 μm.
m was prepared. The OH group concentration was 5 ppm.

[0031]

[Table 1]

The hydrogen treatment of the amorphous silica powder to be treated was performed using the apparatus shown in FIG. First, the raw material of the above-mentioned amorphous silica powder to be treated is made of synthetic quartz glass having an outer diameter of 35.
5 kg was filled in each of powder storage containers 5 each composed of a 4 cm quartz glass crucible. Next, a shielding container 6 made of a quartz glass crucible is arranged, and the inner powder container 5 is placed.
Was obscured. Next, the nitrogen gas introduction pipe valve 10 was opened, and the air in the shielding container was eliminated to fill the container with nitrogen gas. When the air was sufficiently removed, the nitrogen gas introduction pipe valve 10 was closed, the hydrogen gas introduction pipe valve 9 was opened, and pure hydrogen gas was introduced. The flow rate of the hydrogen gas was 0.01 m ³ / min. That is, the hydrogen concentration in the shielding container is set to 100
% By volume. While controlling the furnace temperature to 1000 ° C,
Hydrogen gas was supplied for 3 hours to hydrogen treat the amorphous silica powder. Thereafter, the supply air was switched to nitrogen gas, and the temperature of the system was cooled to room temperature while excluding the hydrogen gas remaining in the system, to obtain a hydrogen-treated synthetic silica glass powder.

The hydroxyl group concentration and the average particle size of the hydrogen-treated synthetic silica glass powder thus obtained were measured. as a result,
Hydroxyl concentration is about 3% compared to untreated amorphous silica powder
Was increasing. The average particle size was 213 μm, which was almost the same as the amorphous silica powder before the hydrogen treatment.
Further, regarding the above synthetic silica glass powder, FT-IR
(Resolution: 4 cm ^-1 , apodization function: Co
sine), and the transmittance spectrum was measured. FIG. 2 shows the transmittance spectrum. As is clear from this figure, no absorption band (peak) was observed at wave numbers of 2360 cm ^-1 and 2330 cm ^-1 .

Next, a quartz glass crucible was manufactured using the synthetic silica glass powder obtained by the hydrogen treatment. First, highly purified crystal powder having an average particle size of 220 μm was put into a container-shaped rotary mold for a quartz glass crucible at room temperature to form an outer wall portion of the crucible. Thereafter, the synthetic silica glass powder was charged into the outer wall of the crucible to form a crucible inner layer. The thickness of each layer was such that the outer wall portion was 70% of the entire crucible wall portion, and the remaining portion was the inner layer portion. While the rotary mold for the crucible on which the silica powder was deposited was continuously rotated, the pressure was reduced from the outside of the mold, and the powder was melted by arc discharge inside the mold, thereby producing a quartz glass crucible having an outer diameter of 45.7 cm. The inner layer of the obtained quartz glass crucible had almost no air bubbles and had a smooth surface. (Example 1)

For comparison, the hydrogen treatment was carried out at a hydrogen concentration of 1
Synthetic silica glass powder was obtained in the same manner as in the above example, except that the reaction was carried out with a mixed gas of hydrogen and nitrogen having a volume percentage of hydrogen. For this, the FT-IR
The transmittance spectrum was measured at. FIG. 3 shows the transmittance spectrum. As is apparent from this figure, although the absorption band at wavenumber 2330cm ^-1 (peak) was not observed, the absorption band at wavenumber 2360 cm ^-1 (peak) was observed. Further, a quartz glass crucible was manufactured in the same manner as in Example 1 except that this synthetic silica glass was used. The appearance of the obtained quartz glass crucible was almost the same as that of Example 1 above. (Comparative Example 1)

For comparison, the transmittance spectrum of amorphous silica produced by the sol-gel method without hydrogen treatment was measured by FT-IR under the same conditions as in Example 1 above. FIG. 4 shows the transmittance spectrum. As is clear from this figure, the wave numbers 2360 cm ⁻¹ and 2330 cm
The absorption band (peak) at ^-1 was observed in each case. A quartz glass crucible was manufactured in the same manner as in Example 1 except that amorphous silica (synthetic silica glass) manufactured by the sol-gel method was used. The appearance of the obtained quartz glass crucible was almost the same as in Example 1 above. (Conventional example)

Using the quartz glass crucibles of Example 1, Comparative Example 1, and the conventional example, about 50 kg of polysilicon was melted under a reduced pressure of about 1333 Pa under an environment of about 1450 ° C., and a silicon single crystal was pulled. . The single crystallization ratios of the obtained silicon single crystal ingots were 98% and 87%, respectively.
% And 85%, which confirms the superiority of Example 1 of the present invention. Observation of each of the quartz glass crucibles after the silicon single crystal pulling operation was completed revealed that no air bubbles were generated in the inner layer (transparent layer) of the crucible of Example 1, and the smooth surface was almost maintained. Was something. On the other hand, in the conventional crucible, about φ
A large number of bubbles of 1 mm were observed, and large irregularities were observed on the inner surface, where a part of bubbles was partially opened. Further, in the crucible of Comparative Example 1, about φ
Generation of bubbles of 0.5 mm was observed, and relatively large irregularities due to swelling of the bubbles were observed on the inner surface.

[0038]

According to the quartz glass crucible using the synthetic silica glass of the present invention, when used for pulling a silicon single crystal, there is no generation or expansion of bubbles on the inner surface of the crucible.
Further, there is an effect that a smooth inner surface is maintained, and as a result, a quartz glass crucible having a high single crystallization ratio can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic view of a batch type apparatus for processing a synthetic quartz glass powder used in the present invention.

FIG. 2 is an FT-IR transmittance spectrum diagram of a hydrogen-treated synthetic silica glass powder obtained in an example of the present invention.

FIG. 3 shows F of synthetic silica glass powder obtained by a comparative example.
It is a T-IR transmittance spectrum figure.

FIG. 4. F of amorphous silica powder obtained by the sol-gel method
It is a T-IR transmittance spectrum figure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace body 2 Furnace floor 4 Quartz glass pedestal 5 Powder storage container 6 Shielding container 7 Synthetic quartz glass powder to be treated 11 Air supply pipe 12 Exhaust pipe

Continuing on the front page (72) Inventor Hiroyuki Kondo 378 Oguni-machi, Oguni-machi, Oguni-machi, Nishiokitama-gun, Yamagata Prefecture Inside (72) Inventor Satsuki Kimura 378 Oguni-machi, Oguni-machi, Oguni-machi, Nishiokitama-gun, Yamagata Toshiba Ceramics Co., Ltd. F term (reference) 4G014 AH08 4G072 AA25 BB05 BB13 DD02 GG03 HH16 JJ01 LL01 MM36 RR11 TT01 TT30 UU01

Claims (6)

[Claims] 1. An amorphous silica powder produced by a sol-gel method, which has a wave number of 2360 cm ^-1 and a wave number of 2360 cm ^-1 in a transmittance spectrum measured by a Fourier transform infrared spectrophotometer.
A synthetic silica glass powder for a quartz glass crucible, characterized in that an absorption band at 30 cm ^-1 is not recognized. 2. The synthetic silica glass powder for a silica glass crucible according to claim 1, wherein the average particle size is 150 to 350 μm and the maximum particle size is 500 μm or less. 3. An amorphous silica powder produced by a sol-gel method is mixed with 10% by volume of hydrogen gas at a temperature of 800 to 1300 ° C.
A method for producing a synthetic silica glass powder for a quartz glass crucible, wherein the heat treatment is performed in an atmosphere containing the above. 4. The quartz glass crucible according to claim 3, wherein the heat treatment temperature and the treatment time for obtaining said synthetic silica glass powder are set within a range in which said synthetic silica glass powder is not crystallized. Of producing synthetic silica glass powder for use. 5. An amorphous silica powder produced by a sol-gel method is treated with hydrogen gas at a temperature of 800.degree.
Synthetic silica glass powder containing substantially as a main component synthetic silica glass powder produced by performing a heat treatment in an atmosphere containing at least volume% is charged into a container-shaped mold and formed into a crucible shape, and the mold is rotated. A method for manufacturing a quartz glass crucible, wherein the melting is performed while arc melting. 6. A crystalline silica powder is charged into a container-like mold to form a crucible, and an amorphous silica powder produced by a sol-gel method is further filled with hydrogen gas at a temperature of 800 ° C. to 1300 ° C. A synthetic silica glass powder produced by performing a heat treatment in an atmosphere containing 10% by volume or more of the silica powder is formed into a crucible shape having a predetermined thickness, and then the arc is melted while rotating the mold. Manufacturing method of glass crucible.