WO2023229031A1

WO2023229031A1 - Quartz glass crucible and production method therefor

Info

Publication number: WO2023229031A1
Application number: PCT/JP2023/019753
Authority: WO
Inventors: 祥貴八木
Original assignee: モメンティブ・テクノロジーズ・山形株式会社
Priority date: 2022-05-27
Filing date: 2023-05-26
Publication date: 2023-11-30
Also published as: JP2023173983A

Abstract

The present invention provides: a quartz glass crucible in which the inner surface of the crucible is crystallized (devitrified) to prevent the release of fine detached matter from the inner surface of the crucible into a silicon melt, and it is also possible to suppress the contamination of the silicon melt and the formation of cracks when pulling up a single crystal; and a production method therefor. Specifically provided is a quartz glass crucible 1 for holding a silicon melt and pulling up a single crystal, said quartz glass crucible comprising an inner layer 4 and at least one outer layer 3 positioned to the outside of the inner layer, wherein a layer 2 including a powder that contains aluminum (Al) is formed in the shape of the crucible in the inner layer.

Description

Quartz glass crucible and its manufacturing method

The present invention relates to a quartz glass crucible for pulling a silicon single crystal by the Czochralski method and a method for manufacturing the same.

To grow silicon single crystals using the Czochralski method, a quartz glass crucible placed in a chamber is filled with polysilicon as a raw material, and a heater placed around the quartz glass crucible heats and melts the polysilicon. , a silicon melt. Thereafter, the seed crystal (seed) attached to the seed chuck is immersed in the silicon melt, and the seed chuck is pulled up while rotating the seed chuck and the quartz glass crucible in the same direction or in opposite directions.

The quartz glass crucible used for pulling silicon single crystals is a quartz member that houses a silicon melt, and the inner surface of the crucible (inner crucible layer) that comes into contact with the melt needs to be a highly pure transparent layer. On the other hand, an opaque outer layer (crucible outer layer) containing a large amount of metal elements other than Si is usually formed on the outer surface of the crucible for the purpose of reducing costs and improving high-temperature mechanical properties.
Specifically, in the inner layer of the crucible, synthetic quartz powder is arranged as a raw material to form a transparent layer, and in the outer layer of the crucible, natural quartz powder is arranged in two or more layers as a raw material to form an opaque layer. A quartz glass crucible is manufactured by melting the formed molded body by arc melting.

By the way, silica glass crucibles are used for pulling silicon single crystals, but it is known that surface roughness such as brown marks occurs on the inner surface of the crucible that comes into contact with silicon melt during pulling. Due to this surface roughness on the crucible inner surface, fine free substances are likely to be generated in the silicon melt from the crucible inner surface. If fine free substances in the silicon melt adhere to the silicon ingot being pulled, there is a possibility that dislocations may occur.

To address this problem, a method has been known in which the inner surface of the crucible is coated with a crystallization accelerator and the inner surface of the crucible is crystallized during use. By crystallizing the inner surface of the crucible, the deformation resistance is strengthened and the occurrence of surface roughness on the inner surface of the crucible is suppressed.
However, when the inner surface of the crucible is coated with a crystallization promoter, another problem arises in that the silicon melt is contaminated by the crystallization promoter.

In order to solve this other problem, Japanese Patent Application Publication No. 2006-124235 discloses a structure in which a crystallization accelerator-containing layer is sandwiched between an inner layer and an outer layer excluding the bottom in a silica glass crucible. . With such a structure, the inner and outer layers can be crystallized during use of the quartz glass crucible to strengthen the deformation resistance and to avoid contamination of the silicon melt by the crystallization accelerator.

However, in the structure disclosed in Japanese Unexamined Patent Publication No. 2006-124235, in which a crystallization accelerator-containing layer is sandwiched between the inner layer and the outer layer of the vitreous silica crucible, the crystallization layer becomes thicker during use of the quartz glass crucible. There was a risk that cracks would occur.

The present invention has been made under the above circumstances, and in a quartz glass crucible for pulling a silicon single crystal by the Czochralski method, the inner surface of the crucible is crystallized during pulling of the single crystal. A quartz glass crucible and a method for manufacturing the same are capable of preventing the generation of fine free substances from the inner surface of the crucible to the silicon melt, as well as suppressing contamination and cracking of the silicon melt. The purpose is to provide.

A quartz glass crucible according to the present invention made to solve the above problem has a bottom, a bottom corner formed around the bottom, and a side extending upward from the bottom corner, and has a silicon melt crucible. A quartz glass crucible for holding a single crystal and pulling a single crystal, the crucible has an inner layer and at least one outer layer disposed outside the inner layer, and the inner layer includes a It is characterized in that a layer containing powder containing aluminum (Al) is formed.

In addition, the layer containing powder containing aluminum (Al) has an aluminum (Al) amount of 4.7 x 10-8 g or more in 0.45 cm3 of quartz glass (glass density 2.2 g/cm3)6. It is desirable that the weight is .6×10 −3 g or less.
Further, in the inner layer, it is desirable that a layer containing the aluminum (Al)-containing powder is formed along the crucible shape at least at the side portions and bottom corners.
Further, it is preferable that the layer containing powder containing aluminum (Al) is a crystallization promoting layer that forms a crystallized layer in the inner layer when pulling a single crystal.

By forming an Al-containing powder layer containing aluminum (Al)-containing powder in the inner layer in this way, aluminum (Al) contained in the aluminum (Al)-containing powder can be removed during silicon single crystal pulling. crystallizes as crystal nuclei in the inner layer and reaches the inner surface of the crucible. Thereby, surface roughness of the inner surface of the crucible that comes into contact with the silicon melt can be suppressed.
Furthermore, since aluminum (Al) is difficult to move in quartz glass, it does not move from the filled position, so that contamination of the silicon melt can be prevented. Furthermore, by forming an Al-containing powder layer as a crystallization accelerator in the inner layer, crystallization of the outer layer can be suppressed and cracks caused by excessive crystallization can be prevented.

Further, a method for manufacturing a quartz glass crucible according to the present invention, which has been made to solve the above-mentioned problems, is the method for manufacturing a quartz glass crucible described above, which comprises supplying a raw material powder containing natural quartz powder to a mold, a step of forming at least one outer layer; a step of supplying raw material powder containing synthetic quartz powder to the inside of the outer layer to form a first inner layer; a step of supplying a mixed powder of a powder containing aluminum (Al) and synthetic quartz powder, and forming a layer of the mixed powder of the powder containing aluminum (Al) and synthetic quartz powder; a step of supplying raw material powder containing synthetic quartz powder to the inside of a layer of mixed powder of powder and synthetic quartz powder to form a second inner layer to obtain a crucible compact; The method is characterized by comprising a step of melting the inner layer and the outer layer to form a quartz glass crucible.
Furthermore, a mixed powder of a powder containing aluminum (Al) and a synthetic quartz powder is supplied to the inside of the first inner layer, and a mixed powder of the powder containing aluminum (Al) and a synthetic quartz powder is supplied. In the step of forming the layer, it is desirable that the aluminum (Al)-containing powder has a smaller particle size than the synthetic quartz powder to be mixed, and has an aluminum (Al) concentration of 50 ppm or more and 1% or less.

According to such a method, an Al-containing powder layer containing powder containing aluminum (Al) can be formed in the inner layer. As a result, aluminum (Al) contained in the Al-containing powder is crystallized as crystal nuclei in the inner layer during pulling of the silicon single crystal, and reaches the inner surface of the crucible. Thereby, surface roughness of the inner surface of the crucible that comes into contact with the silicon melt can be suppressed.
Furthermore, since aluminum (Al) is difficult to move in quartz glass, it does not move from the filled position, so that contamination of the silicon melt can be prevented. Furthermore, by forming an Al-containing powder layer as a crystallization accelerator in the inner layer, crystallization of the outer layer can be suppressed and cracks caused by excessive crystallization can be prevented.

According to the present invention, in a quartz glass crucible for pulling a silicon single crystal for pulling a single crystal by the Czochralski method, the inner surface of the crucible is crystallized (devitrified) when pulling the single crystal, and the crucible is It is possible to provide a silica glass crucible and a method for manufacturing the same, which can prevent the generation of fine free substances from the inner surface of the silicon melt and suppress contamination and cracking of the silicon melt.

FIG. 1 is a cross-sectional view of a quartz glass crucible according to the present invention. FIG. 2 is a partially enlarged sectional view of the quartz glass crucible shown in FIG. FIG. 3 is a sectional view further enlarging a part of the partially enlarged sectional view of the quartz glass crucible in FIG. 2. FIG. FIG. 4 is a schematic diagram of an apparatus for manufacturing the quartz glass crucible of FIG. 1.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a silica glass crucible and a manufacturing method thereof according to the present invention will be described based on the drawings. FIG. 1 is a cross-sectional view of a quartz glass crucible 1 according to the present invention. FIG. 2 is a partially enlarged sectional view of the quartz glass crucible shown in FIG.
This quartz glass crucible 1 is used, for example, in a single crystal pulling device (not shown), and is used in a state where it is supported by a carbon susceptor (not shown) within the device. That is, in the single crystal pulling apparatus, raw silicon is melted in the quartz glass crucible 1, and a silicon single crystal is pulled from the melt.

The quartz glass crucible 1 is formed to have a diameter (aperture) of 32 inches and a height of 500 mm, for example, and has a bottom portion 9 having a predetermined curvature (first curvature) and a bottom portion 9 having a predetermined curvature (first curvature). It has a bottom corner 8 having a curvature of 2.5 mm, and a side portion (straight body portion) 7 extending upward from the bottom corner 8.
As shown in FIG. 1, an opaque outer layer 3 made of natural raw quartz glass is formed on the outer side of the side portion 7. Further, inside this outer layer 3, a transparent inner layer 4 made of high-purity synthetic raw material quartz glass is formed, which comes into contact with the silicon melt during pulling of the silicon single crystal.

Here, opaque means that the quartz glass contains many air bubbles (pores) and appears cloudy. Furthermore, a natural quartz layer refers to a silica glass layer manufactured by melting natural raw materials such as crystal, and a synthetic quartz layer refers to a silica glass layer manufactured by melting synthetic raw materials synthesized by hydrolysis of silicon alkoxide, for example. silica glass layer.

Further, as shown in the figure, at the

bottom corners

8 and 9 of the vitreous silica crucible 1, an outer layer 3 made of natural raw material quartz glass is formed continuously from the outer layer 3 of the side part 7, and an inner layer made of synthetic raw material quartz glass. It has a two-layer structure formed of 4 and 4.

As shown in FIG. 2, the outer layer 3 made of natural raw material quartz glass has a thickness ot1 of 6 mm or more at the side 7 of the quartz glass crucible 1. Moreover, the thickness dimension ot2 of the bottom corner 8 formed continuously from the outer layer 3 in the outer layer 3 and the thickness dimension ot3 of the bottom part 9 in the outer layer 3 are also formed to be 6 mm or more.
This is because if the thickness ot1 of the outer layer 3 at the side 7, the thickness ot2 of the outer layer 3 at the bottom corner 8, and the thickness ot3 of the outer layer 3 at the bottom 9 are smaller than 6 mm, sufficient durability can be obtained. This is because it is difficult.

The inner layer 4 is a transparent layer substantially free of bubbles formed by melting synthetic raw material quartz glass. In the inner layer 4, the thickness dimension it1 at the side portion 7 is formed to be 1.5 mm or more and 4 mm or less, preferably 2 mm or more and 3 mm or less.
By forming the thickness dimension it1 of the side portion 7 in such a range, it is possible to prevent the crucible opening from deforming (falling down, etc.) and exposing the crucible outer layer.
Further, in the inner layer 4, the thickness dimension it2 at the bottom corner 8 is formed to be 1.5 mm or more and 6 mm or less, preferably 2 mm or more and 4 mm or less. Further, in the inner layer 4, the thickness dimension it3 at the bottom part 9 is formed to be 1.5 mm or more and 4 mm or less, preferably 2 mm or more and 3 mm or less, similarly to the side part 7.

Further, in the inner layer 4, a layer (referred to as an Al-containing powder layer) 2 containing powder containing aluminum (Al) as a crystal nucleus (Al-containing powder) is formed. This Al-containing powder layer 2 is a layer containing the Al-containing powder in a quartz glass layer, and as shown in FIG. It is located at a position of .25 mm or more and 1.75 mm or less, and the thickness W is formed to be 0.1 mm or more and 0.5 mm or less.
Thereby, the Al-containing powder layer 2 can be prevented from being exposed even when the inner surface of the crucible is etched by the silicon melt, and it can be devitrified. If the Al-containing powder layer 2 is shallower than 1.25 mm from the inner surface of the crucible, there is a risk that the Al-containing powder layer 2 will be exposed due to etching of the crucible by the silicon melt. On the other hand, if the Al-containing powder layer 2 is deeper than 1.75 mm from the crucible inner surface, there is a possibility that the entire crucible inner surface may not be devitrified.

The amount of Al in 0.45 cm3 of quartz glass in the Al-containing powder layer 2 is set to be 4.7 x 10-8 g or more and 6.6 x 10-3 g or less.
Further, the Al concentration of the Al-containing powder in the Al-containing powder layer 2 is set to 5.0×10 −5% (50 ppm) or more and 1% (104 ppm) or less. If the Al concentration in the Al-containing powder in the Al-containing powder layer 2 is thinner than 50 ppm, it will take time to devitrify, and if it is thicker than 1% (104 ppm), devitrification will occur excessively, resulting in a crack occurrence rate. There is a risk that this will increase.

By forming the Al-containing powder layer 2 containing powder containing aluminum (Al) in the inner layer 4, the aluminum (Al) in the Al-containing powder becomes a crystal nucleus during pulling of the silicon single crystal into the inner layer 4. (that is, the Al-containing powder layer 2 functions as a crystallization promoting layer to form a crystallized layer), and as the crystallization reaches the inner surface of the crucible, the silicon melt comes into contact with it. Surface roughness on the inner surface of the crucible can be suppressed.
Furthermore, since aluminum (Al) is difficult to move in quartz glass, it does not move from the filled position, so that contamination of the silicon melt can be prevented. Furthermore, by forming an Al-containing powder layer 2 containing powder containing aluminum (Al) as a crystallization promoter in the inner layer 4, crystallization on the outer layer 3 side is suppressed, and cracks due to excessive crystallization are prevented. Occurrence can be prevented.

Next, a method for manufacturing the silica glass crucible 1 having the above structure will be explained.
The quartz glass crucible 1 according to the present embodiment is manufactured using, for example, a quartz glass crucible manufacturing apparatus 10 as shown in FIG. 4.
The crucible molding mold 11 of the quartz glass crucible manufacturing apparatus 10 includes an inner member 12 made of a gas permeable member such as a mold having a plurality of through holes or a highly purified porous carbon mold. , and a holder 14 that holds the inner member 12 and has a ventilation portion 13 on its outer periphery.

Further, a rotating shaft 15 connected to a rotating means (not shown) is fixed to the lower part of the holder 14, and rotatably supports the crucible molding mold 11. The ventilation section 13 is connected to an exhaust passage 17 provided at the center of the rotating shaft 15 via an opening 16 provided at the bottom of the holder 14 , and this exhaust passage 17 is connected to a pressure reduction mechanism 18 . has been done.
An arc electrode 19 for arc discharge, a natural quartz powder supply nozzle 20, an Al-containing powder supply nozzle 21, and a synthetic quartz powder supply nozzle 22 are provided at the upper part facing the inner member 12.

When manufacturing a quartz glass crucible using the quartz glass crucible manufacturing apparatus 10, a rotation drive source (not shown) is operated to rotate the rotating shaft 18 in the direction of the arrow, thereby rotating the crucible molding mold 11 at high speed.
Next, natural quartz powder (raw material powder) is supplied into the crucible mold 11 from the natural quartz powder supply nozzle 20 . The supplied natural quartz powder is pressed against the inner surface of the inner member 12 by centrifugal force, and is formed as an outer layer 30 having a thickness of 6 mm or more at the sides, bottom corners, and bottom.

Next, first, synthetic quartz powder (raw material powder) is fed through a synthetic quartz powder supply nozzle so that a layer 40a (first inner layer) of synthetic quartz powder with a thickness of, for example, 1.5 mm is formed on the inner surface side of the outer layer 30. Supplied from 23.
The supplied synthetic quartz powder is pressed against the inner surface of the outer layer 30 by centrifugal force and is formed into a layer 40a of synthetic quartz powder.

Next, a layer 25 of Al-containing powder mixed quartz powder (mixed powder of Al-containing powder and synthetic quartz powder) having a thickness of 0.1 mm or more and 1.0 mm or less is formed on the inner surface side of the synthetic quartz powder layer 40a. quartz powder mixed with Al-containing powder of 5% or more and 30% or less of the weight of the crucible is supplied from the Al-containing powder supply nozzle 21 so that the crucible is formed.
The supplied quartz powder mixed with Al-containing powder is pressed against the inner surface of the layer 40a of synthetic quartz powder by centrifugal force, and is formed into a layer 25 of quartz powder mixed with Al-containing powder.

The Al-containing powder mixed quartz powder supplied from the Al-containing powder supply nozzle 21 is formed in advance in the following manner.
That is, a solution in which an Al compound is dissolved and quartz powder are mixed and dried to refine the Al-containing powder. Thereafter, Al-containing powder mixed quartz powder is produced by mixing Al-containing powder and synthetic quartz powder. The particle size of the Al-containing powder is smaller than the synthetic quartz powder to be mixed, preferably from 270 mesh (opening 53 μm) to 18 mesh (opening 1000 μm), and from 230 mesh (opening 63 μm) to 45 It is more preferable to use a mesh (opening: 354 μm) or less. When the particle size is larger than 1.0 mm, bubbles may be generated in the Al-containing layer 2. On the other hand, if the particle size is smaller than 0.1 mm, unevenness will occur when mixed with the quartz raw material. Further, the Al concentration in the powder containing Al is set to 5.0×10 −5% (50 ppm) or more and 1% (104 ppm) or less. Since the Al-containing powder mixed quartz powder contains quartz powder, the amount of Al in 0.45 cm3 of quartz glass at the time of forming the quartz glass crucible is 4.7 x 10-8 g or more 6.6 x 10- 3g or less.

After forming the layer 25 of quartz powder mixed with Al-containing powder, a layer 40b of synthetic quartz powder (second inner layer) with a thickness of 1.25 mm or more and 1.75 mm or less is formed on the inner surface of the layer 25 of quartz powder mixed with Al-containing powder. ) is formed from the synthetic quartz powder supply nozzle 23.
The supplied synthetic quartz powder is pressed by centrifugal force against the inner surface of the layer 25 of quartz powder mixed with Al-containing powder, and is formed into a layer 40b of synthetic quartz powder.
Here, the thickness dimension (thickness of the inner layer 40) between the outer surface of the synthetic quartz powder layer 40a and the inner surface of the synthetic quartz powder layer 40b is, for example, 2 mm.

In this way, a crucible molded body consisting of the outer layer 30 and the inner layer 40 (including the layer 25 of quartz powder mixed with Al-containing powder) is obtained.
Furthermore, the pressure inside the inner member 12 is reduced by the operation of the pressure reducing mechanism 18, and the arc electrode 19 is energized to heat the crucible molded body from the inside, thereby forming the inner layer 40 of the crucible molded body, the layer 25 of the Al-containing powder mixed quartz powder, and the outer layer. 30 is melted to produce a quartz glass crucible 1 having an inner layer 4 and an outer layer 3.

As described above, according to the present embodiment, by forming the Al-containing powder layer 2 containing powder containing aluminum (Al) in the inner layer 4, aluminum Aluminum (Al) contained in the powder is crystallized as crystal nuclei in the inner layer 4 and reaches the inner surface of the crucible. Thereby, surface roughness of the inner surface of the crucible that comes into contact with the silicon melt can be suppressed.
Furthermore, since aluminum (Al) is difficult to move in quartz glass, it does not move from the filled position, so that contamination of the silicon melt can be prevented. Furthermore, by forming the Al-containing powder layer 2 as a crystallization accelerator in the inner layer 4, crystallization on the outer layer 3 side can be suppressed and cracks caused by excessive crystallization can be prevented.

In the embodiment described above, the Al-containing powder layer 2 is formed over the entire inner layer 4 of the silica glass crucible 1 (the side portion 7, the bottom corner 8, and the bottom portion 9). is not limited to this configuration. However, the Al-containing powder layer 2 is preferably formed on at least the side portions 7 and bottom corners 8 of the inner layer 4 of the quartz glass crucible 1 .
Further, although the silica glass crucible 1 has a two-layer structure of the outer layer 3 and the inner layer 4, the present invention is not limited to this structure, and the outer layer may have two or more layers. .

Next, the silica glass crucible and the manufacturing method thereof according to the present invention will be further explained based on Examples. In this example, a silica glass crucible having the configuration shown in the embodiment described above was manufactured, and the effects of the present invention were verified.
In addition, the measurement of Al concentration in the following Examples and Comparative Examples was carried out in accordance with JIS M8852 (1998), by taking several grams of samples from the target area of the crucible, and using a sample containing hydrofluoric acid (HF) as the main component. It was dissolved in a mixed solution and measured by Inductively Coupled Plazma Atomic Emission Spectroscopy (ICP-AES).

(Example 1)
A quartz glass crucible of 32 inches and a height of 500 mm was manufactured using the quartz glass crucible manufacturing apparatus shown in FIG. This quartz glass crucible had a two-layer structure: an inner layer made of synthetic raw material quartz glass and an outer layer made of natural raw material quartz glass. An Al-containing powder layer was formed in the inner layer.
The size of the powder contained in the Al-containing powder layer was 45 to 230 mesh. The Al-containing powder layer was formed with a thickness of 0.1 mm or more and 0.5 mm or less at a depth of 1.25 mm or more and 1.75 mm or less from the inner surface of the crucible.
Further, the aluminum (Al) concentration in the powder contained in the Al-containing powder layer was set to 50 ppm or more and 104 ppm (1%) or less.
Further, the weight ratio of the Al-containing powder layer to the entire crucible was set to 5% or more and 30% or less of the crucible weight.

In Example 1, a silicon single crystal was pulled using the manufactured silica glass crucible, and the devitrification state of the inner surface of the crucible was observed.
As a result, the entire inner surface of the crucible was devitrified, and no surface roughness on the inner surface of the crucible, floating objects in the silicon melt, or contamination of the silicon melt were observed. Further, no adverse effect on single crystal pulling was observed.

(Comparative example 1)
In Comparative Example 1, a quartz glass crucible having a size of 32 inches and a height of 500 mm was manufactured using the quartz glass crucible manufacturing apparatus shown in FIG. 4 in the same manner as in Example 1. This quartz glass crucible had a two-layer structure: an inner layer made of synthetic raw material quartz glass and an outer layer made of natural raw material quartz glass. No Al-containing powder layer was formed in the inner layer.

In Comparative Example 1, a silicon single crystal was pulled using the manufactured silica glass crucible, and the devitrification state of the inner surface of the crucible was observed.
As a result, no abnormality was observed in the pulling of the silicon single crystal, but no devitrification was observed on the inner surface of the crucible.

(Comparative example 2)
In Comparative Example 2, similarly to Example 1, a quartz glass crucible having a size of 32 inches and a height of 500 mm was manufactured using the quartz glass crucible manufacturing apparatus shown in FIG. This quartz glass crucible had a two-layer structure: an inner layer made of synthetic raw material quartz glass and an outer layer made of natural raw material quartz glass. An Al-containing powder layer was formed in the inner layer.
The size of the powder contained in the Al-containing powder layer was 35 mesh. The Al-containing powder layer was formed with a thickness of 0.1 mm or more and 0.5 mm or less at a depth of 1.25 mm or more and 1.75 mm or less from the inner surface of the crucible.
Further, the aluminum (Al) concentration in the powder contained in the Al-containing powder layer was set to 50 ppm or more and 104 ppm (1%) or less.
Further, the weight ratio of the Al-containing powder layer to the entire crucible was set to 5% or more and 30% or less of the crucible weight.

In Comparative Example 2, a silicon single crystal was pulled using the manufactured silica glass crucible, and the devitrification state of the inner surface of the crucible was observed.
As a result, microbubbles were generated in the inner layer of the crucible, resulting in an unfavorable condition.

(Comparative example 3)
In Comparative Example 3, similarly to Example 1, a quartz glass crucible having a size of 32 inches and a height of 500 mm was manufactured using the quartz glass crucible manufacturing apparatus shown in FIG. This quartz glass crucible had a two-layer structure: an inner layer made of synthetic raw material quartz glass and an outer layer made of natural raw material quartz glass. An Al-containing powder layer was formed in the inner layer.
The size of the powder contained in the Al-containing powder layer was 45 to 230 mesh. The Al-containing powder layer was formed at a depth of 1.20 mm from the inner surface of the crucible with a thickness of 0.1 mm or more and 0.5 mm or less.
Further, the aluminum (Al) concentration in the powder contained in the Al-containing powder layer was set to 50 ppm or more and 104 ppm (1%) or less.
Further, the weight ratio of the Al-containing powder layer to the entire crucible was set to 5% or more and 30% or less of the crucible weight.

In Comparative Example 3, a silicon single crystal was pulled using the manufactured silica glass crucible, and the devitrification state of the inner surface of the crucible was observed.
As a result, the Al-containing powder layer was exposed on the surface of the inner layer of the crucible.

(Comparative example 4)
In Comparative Example 4, similarly to Example 1, a quartz glass crucible with a size of 32 inches and a height of 500 mm was manufactured using the quartz glass crucible manufacturing apparatus shown in FIG. This quartz glass crucible had a two-layer structure: an inner layer made of synthetic raw material quartz glass and an outer layer made of natural raw material quartz glass. An Al-containing powder layer was formed in the inner layer.
The size of the powder contained in the Al-containing powder layer was 45 to 230 mesh. The Al-containing powder layer was formed at a depth of 1.80 mm from the inner surface of the crucible with a thickness of 0.1 mm or more and 0.5 mm or less.
Further, the aluminum (Al) concentration in the powder contained in the Al-containing powder layer was set to 50 ppm or more and 104 ppm (1%) or less.
Further, the weight ratio of the Al-containing powder layer to the entire crucible was set to 5% or more and 30% or less of the crucible weight.

In Comparative Example 4, a silicon single crystal was pulled using the manufactured silica glass crucible, and the devitrification state of the inner surface of the crucible was observed.
As a result, no abnormality was observed in the pulling of the silicon single crystal, but the inner surface of the crucible was partially devitrified.

(Comparative example 5)
In Comparative Example 5, similarly to Example 1, a quartz glass crucible of 32 inches and height of 500 mm was manufactured using the quartz glass crucible manufacturing apparatus shown in FIG. This quartz glass crucible had a two-layer structure: an inner layer made of synthetic raw material quartz glass and an outer layer made of natural raw material quartz glass. An Al-containing powder layer was formed in the inner layer.
The size of the powder contained in the Al-containing powder layer was 45 to 230 mesh. The Al-containing powder layer was formed with a thickness of 0.08 mm at a depth of 1.25 to 1.75 mm from the inner surface of the crucible.
Further, the aluminum (Al) concentration in the powder contained in the Al-containing powder layer was set to 50 ppm or more and 104 ppm (1%) or less.
Further, the weight ratio of the Al-containing powder layer to the entire crucible was set to 5% or more and 30% or less of the crucible weight.

In Comparative Example 5, a silicon single crystal was pulled using the manufactured silica glass crucible, and the devitrification state of the inner surface of the crucible was observed.
As a result, no abnormality was observed in the pulling of the silicon single crystal, but the inner surface of the crucible was partially devitrified.

(Comparative example 6)
In Comparative Example 6, similarly to Example 1, a quartz glass crucible of 32 inches and height of 500 mm was manufactured using the quartz glass crucible manufacturing apparatus shown in FIG. This quartz glass crucible had a two-layer structure: an inner layer made of synthetic raw material quartz glass and an outer layer made of natural raw material quartz glass. An Al-containing powder layer was formed in the inner layer.
The size of the powder contained in the Al-containing powder layer was 45 to 230 mesh. The Al-containing powder layer was formed with a thickness of 0.6 mm at a depth of 1.75 mm from the inner surface of the crucible.
Further, the aluminum (Al) concentration in the powder contained in the Al-containing powder layer was set to 50 ppm or more and 104 ppm (1%) or less.
Further, the weight ratio of the Al-containing powder layer to the entire crucible was set to 5% or more and 30% or less of the crucible weight.

In Comparative Example 6, a silicon single crystal was pulled using the manufactured silica glass crucible, and the devitrification state of the inner surface of the crucible was observed.
As a result, no abnormality was observed in the pulling of the silicon single crystal, but devitrification reached the outer layer (there is a risk of liquid leakage due to excessive devitrification).

(Comparative Example 7)
In Comparative Example 7, similarly to Example 1, a quartz glass crucible of 32 inches and height of 500 mm was manufactured using the quartz glass crucible manufacturing apparatus shown in FIG. This quartz glass crucible had a two-layer structure: an inner layer made of synthetic raw material quartz glass and an outer layer made of natural raw material quartz glass. An Al-containing powder layer was formed in the inner layer.
The size of the powder contained in the Al-containing powder layer was 45 to 230 mesh. The Al-containing powder layer was formed with a thickness of 0.1 mm or more and 0.5 mm or less at a depth of 1.25 mm or more and 1.75 mm or less from the inner surface of the crucible.
Further, the aluminum (Al) concentration in the powder contained in the Al-containing powder layer was 45 ppm.
Further, the weight ratio of the Al-containing powder layer to the entire crucible was set to 5% or more and 30% or less of the crucible weight.

In Comparative Example 7, a silicon single crystal was pulled using the manufactured silica glass crucible, and the devitrification state of the inner surface of the crucible was observed.
As a result, no abnormality was observed in the pulling of the silicon single crystal, but the inner surface of the crucible was partially devitrified.

(Comparative example 8)
In Comparative Example 8, similarly to Example 1, a quartz glass crucible of 32 inches and 500 mm in height was manufactured using the quartz glass crucible manufacturing apparatus shown in FIG. This quartz glass crucible had a two-layer structure: an inner layer made of synthetic raw material quartz glass and an outer layer made of natural raw material quartz glass. An Al-containing powder layer was formed in the inner layer.
The size of the powder contained in the Al-containing powder layer was 45 to 230 mesh. The Al-containing powder layer was formed with a thickness of 0.1 mm or more and 0.5 mm or less at a depth of 1.25 mm or more and 1.75 mm or less from the inner surface of the crucible.
Further, the aluminum (Al) concentration in the powder contained in the Al-containing powder layer was 1.1%.
Further, the weight ratio of the Al-containing powder layer to the entire crucible was set to 5% or more and 30% or less of the crucible weight.

In Comparative Example 8, a silicon single crystal was pulled using the manufactured silica glass crucible, and the devitrification state of the inner surface of the crucible was observed.
As a result, no abnormality was observed in the pulling of the silicon single crystal, and the inner surface of the crucible was completely devitrified, but it was excessively devitrified and a slight crack occurred.

(Comparative Example 9)
In Comparative Example 9, similarly to Example 1, a quartz glass crucible of 32 inches and 500 mm in height was manufactured using the quartz glass crucible manufacturing apparatus shown in FIG. This quartz glass crucible had a two-layer structure: an inner layer made of synthetic raw material quartz glass and an outer layer made of natural raw material quartz glass. An Al-containing powder layer was formed in the inner layer.
The size of the powder contained in the Al-containing powder layer was 45 to 230 mesh. The Al-containing powder layer was formed with a thickness of 0.1 mm or more and 0.5 mm or less at a depth of 1.25 mm or more and 1.75 mm or less from the inner surface of the crucible.
Further, the aluminum (Al) concentration in the powder contained in the Al-containing powder layer was set to 50 ppm or more and 104 ppm (1%) or less.
Further, the weight ratio of the Al-containing powder layer to the entire crucible was 4% of the crucible weight.

In Comparative Example 9, a silicon single crystal was pulled using the manufactured silica glass crucible, and the devitrification state of the inner surface of the crucible was observed.
As a result, devitrification did not occur to the inner surface of the crucible, and the effects of the present invention could not be obtained.

(Comparative Example 10)
In Comparative Example 10, similarly to Example 1, a quartz glass crucible of 32 inches and height of 500 mm was manufactured using the quartz glass crucible manufacturing apparatus shown in FIG. This quartz glass crucible had a two-layer structure: an inner layer made of synthetic raw material quartz glass and an outer layer made of natural raw material quartz glass. An Al-containing powder layer was formed in the inner layer.
The size of the powder contained in the Al-containing powder layer was 45 to 230 mesh. The Al-containing powder layer was formed with a thickness of 0.1 mm or more and 0.5 mm or less at a depth of 1.25 mm or more and 1.75 mm or less from the inner surface of the crucible.
Further, the aluminum (Al) concentration in the powder contained in the Al-containing powder layer was set to 50 ppm or more and 104 ppm (1%) or less.
Further, the weight ratio of the Al-containing powder layer to the entire crucible was 31% of the crucible weight.

In Comparative Example 9, a silicon single crystal was pulled using the manufactured silica glass crucible, and the devitrification state of the inner surface of the crucible was observed.
As a result, the entire inner surface of the crucible was devitrified, but it was excessively devitrified and cracks were slightly generated.

Table 1 shows the conditions and devitrification results of Example 1 and Comparative Examples 1 to 10.

From the results shown in Table 1, Example 1 was able to obtain the effects of the present invention. Therefore, as in Example 1, the powder size is preferably 45 mesh to 230 mesh, the Al-containing powder layer is located at a position of 1.25 mm to 1.75 mm from the inner surface of the crucible, and has a thickness of 0. It was confirmed that .1 mm or more and 0.5 mm or less is preferable.
Further, the Al concentration in the powder contained in the Al-containing powder layer is preferably 50 ppm or more and 1% or less, and the weight ratio of the Al-containing powder layer to the entire crucible is preferably 5% or more and 30% or less of the crucible weight. I confirmed.

1 Quartz glass crucible 2 Al-containing powder layer 3 Outer layer 4 Inner layer 7 Side part 8 Bottom corner 9 Bottom part 10 Quartz glass crucible manufacturing device 25 Al-containing powder mixed quartz powder (mixed powder of Al-containing powder and synthetic quartz powder) layer 40a first inner layer 40b second inner layer

Claims

A quartz glass crucible for holding a silicon melt and for pulling a single crystal, the crucible having a bottom, a bottom corner formed around the bottom, and a side extending upward from the bottom corner, the crucible comprising:
comprising an inner layer and at least one outer layer disposed outside the inner layer,
A quartz glass crucible, wherein a layer containing powder containing aluminum (Al) is formed in the inner layer along the shape of the crucible.
In the layer containing powder containing aluminum (Al), the amount of aluminum (Al) in 0.45 cm3 of quartz glass (glass density 2.2 g/cm3) is 4.7 x 10-8 g or more 6.6 x The quartz glass crucible according to claim 1, characterized in that the weight is 10-3 g or less.
2. The inner layer according to claim 1, wherein the layer containing the aluminum (Al)-containing powder is formed along the shape of the crucible at least at the side and bottom corners. Quartz glass crucible.
The layer containing powder containing aluminum (Al) is a crystallization promoting layer that forms a crystallized layer in the inner layer when pulling a single crystal. Quartz glass crucible.
A method for manufacturing a silica glass crucible according to any one of claims 1 to 4, comprising:
supplying raw material powder containing natural quartz powder to a mold to form at least one outer layer;
a step of supplying raw material powder containing synthetic quartz powder to the inside of the outer layer to form a first inner layer; and a step of supplying powder containing aluminum (Al) and synthetic quartz powder to the inner side of the first inner layer. supplying a mixed powder and forming a layer of the mixed powder of the aluminum (Al)-containing powder and synthetic quartz powder;
supplying raw material powder containing synthetic quartz powder inside the layer of mixed powder of the aluminum-containing powder and synthetic quartz powder to form a second inner layer to obtain a crucible molded body;
A method for manufacturing a quartz glass crucible, comprising the step of melting an inner layer and an outer layer of the crucible molded body to form a quartz glass crucible.
A mixed powder of aluminum (Al)-containing powder and synthetic quartz powder is supplied inside the first inner layer to form a layer of the mixed powder of the aluminum-containing powder and synthetic quartz powder. In the process,
The powder containing aluminum (Al) has a smaller particle size than the synthetic quartz powder to be mixed, and has an aluminum (Al) concentration of 50 ppm or more and 1% or less. A method for manufacturing a quartz glass crucible.