JP3717151B2 - Method for producing quartz glass crucible for pulling silicon single crystal - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a quartz glass crucible for pulling up a silicon single crystal, and more particularly to a method for producing a quartz glass crucible for pulling up a silicon single crystal in which the inner surface of the quartz glass crucible is made bubble-free.
[0002]
[Prior art]
A silicon single crystal used for a substrate of a semiconductor device is generally manufactured by the Czochralski method (CZ method). In this CZ method, a polycrystalline silicon raw material is loaded into a quartz glass crucible, and the loaded silicon raw material is surrounded by The seed crystal which is heated and melted from above and suspended from above is brought into contact with the silicon melt and pulled up.
[0003]
Conventional quartz glass crucibles are formed by methods such as vacuum melting, but when the silicon single crystal is pulled up, if the quartz glass crucible becomes hot, bubbles are generated in the transparent layer, the quartz glass crucible deforms, The liquid is eroded from the surface, but due to the erosion, the bubbles in the transparent layer (inner layer) of the silica glass crucible are exposed at the interface with the silicon melt, and the single crystallization becomes unstable. As a result, there was a problem that the yield of single crystallization decreased. Bubbles generated in the transparent layer are mainly composed of oxygen, and a portion with a large amount of impurities and structural water serves as the core of the bubble, and the surrounding oxygen diffuses into the formed bubble and grows.
[0004]
Therefore, in recent years, various production methods for making the transparent layer of the quartz glass crucible be made bubble-free have been studied, but the present situation is that the bubble-free crucible has not yet been completely bubble-free. In contrast, even if the bubbles in the transparent layer were significantly reduced, the single crystal yield of silicon single crystals, which required high quality, was never improved to a degree that was sufficiently satisfied.
[0005]
Conventionally, a method for producing a quartz glass crucible in which a quartz raw material powder in a mold is melted under reduced pressure to form a transparent layer inside the quartz glass crucible has been performed. Bubbles remain in the layer. When a silicon single crystal is pulled using a quartz glass crucible manufactured by such a manufacturing method, bubbles are expanded in the transparent layer, and bubbles are mixed into the silicon melt as the transparent layer on the inner surface side is dissolved. There is a problem that bubbles are taken into the silicon single crystal and cause dislocation (crystal defects) due to crystal dislocation, which causes a decrease in the single crystallization rate.
[0006]
Furthermore, various manufacturing methods for making the transparent layer of the quartz glass crucible air-free have been studied.
[0007]
For example, in Japanese Patent Laid-Open No. 1-157427, quartz raw material powder is supplied into a mold having air permeability, a crucible-shaped molded body is formed, and then decompressed, and hydrogen gas, helium gas, or a mixture thereof A method for producing a quartz glass crucible by supplying gas from the start of melting is described. According to this manufacturing method, hydrogen gas and helium gas are diffused in the transparent layer of the quartz glass crucible, and gases other than this gas cannot be diffused. When the quartz glass crucible is manufactured by supplying helium gas from the start to the end of melting, there is a problem similar to the manufacturing method described above, and hydrogen gas is lost. Alternatively, when a quartz glass crucible is manufactured by supplying a mixed gas of hydrogen gas and helium gas from the start to the end of melting, the expansion of bubbles during pulling of the silicon single crystal can be suppressed, but the surface layer of the transparent layer is about 1 mm. It is difficult to make the number of bubbles as close to zero as possible, resulting in the separation of small pieces of quartz glass, leading to a decrease in single crystallization rate, and quartz glass. OH concentration in the pot increases, decreases the viscosity of the quartz glass, there is a possibility that the quartz glass crucible is deformed in the silicon single crystal pulling.
[0008]
Therefore, the present inventors diligently studied a method for producing a quartz glass crucible that can bring the number of bubbles as close to zero as possible and can obtain a high single crystallization rate in the CZ method. As a result, it has been concluded that it is effective to remove bubbles that are inevitably mixed into the inner surface of the quartz glass crucible formed by arc melting in the next step.
[0009]
As a related art related to this, a method for regenerating a quartz glass crucible is proposed in Japanese Patent Laid-Open No. 2-188489. This reclaiming method consists of mechanically grinding or etching foreign matter other than glassy silica contained in the inner surface layer of protrusions present on the inner surface of the quartz glass crucible that has been determined to be defective, and then the peripheral portion of this grinding mark or etching mark. Is a method for regenerating a quartz glass crucible that is smoothened by heat treatment. However, when this regeneration method is applied to the above-described removal of bubbles, the bubble concentration portions existing at a number of locations are each partially subjected to, for example, mechanical grinding, and the peripheral portion of the grinding trace is heat-treated with an oxyhydrogen burner. Even if it is smooth, there will be at least some irregularities on the inner surface of the crucible, which may partially disturb the convection of the silicon melt, leading to a decrease in the single crystallization rate, and roughing the mechanical grinding. When this is used, it is not possible to remove all microcrack damage that has occurred to this depth during grinding, and the inner surface of the crucible is eroded by the silicon melt. It was confirmed that the selective erosion of the steel accelerated and the service life was shortened.
[0010]
In addition, in the above regeneration method, as the heat treatment after grinding, in addition to the heat treatment with an oxyhydrogen burner, the heat treatment with an arc flame is mentioned. In this case, the inner surface of the crucible after the heat treatment has Al, Ca. It was confirmed that impurities such as The reason for this is not clear, but the heat treatment with the arc flame has a considerably higher atmospheric temperature than the heat treatment with the oxyhydrogen burner, and the surface SiO 2 is heated during ₂ Will evaporate. At this time, SiO ₂ It is presumed that impurities such as Al and Ca having a lower vapor pressure remain in a concentrated state.
[0011]
[Problems to be solved by the invention]
Therefore, a method for producing a quartz glass crucible for pulling up a silicon single crystal, in which even if the silicon single crystal is pulled, bubbles are not taken into the pulled single crystal, dislocations do not occur, and a high single crystallization rate can be obtained. Is desired.
[0012]
The present invention has been made in consideration of the above-described circumstances, and even when a silicon single crystal is pulled, bubbles are not taken into the pulled single crystal, dislocations do not occur, and a high single crystallization rate is achieved. It aims at providing the manufacturing method of the quartz glass crucible for silicon single crystal pulling obtained.
[0013]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the invention of claim 1 of the present application is to polish the entire inner surface of a molten crucible in which a quartz raw material powder is supplied into a rotating mold to form a crucible-shaped body and arc-melted. , Manufacturing method of quartz glass crucible for pulling silicon single crystal by heat treatment of polished surface with oxyhydrogen burner Then, before the polishing treatment, the entire inner surface of the melting crucible is ground to 3 μm or less with Ra. The gist of the present invention is a method for producing a quartz glass crucible for pulling a silicon single crystal.
[0017]
Claim of this application 2 In the invention, the grinding is performed using a diamond grindstone having a diamond particle diameter of 80 mesh or more. 1 The manufacturing method of the silica glass crucible for pulling up a silicon single crystal described in 1) is summarized.
[0018]
Claim of this application 3 In the invention, the grinding is performed by sandblasting using fine abrasive grains having a grain size of 90 mesh or more. 1 The manufacturing method of the silica glass crucible for pulling up a silicon single crystal described in 1) is summarized.
[0019]
Claim of this application 4 According to the invention, after the grinding, re-grinding is performed using a diamond grindstone having a diamond particle size of 200 mesh or more. 2 Or 3 The manufacturing method of the silica glass crucible for pulling up a silicon single crystal described in 1) is summarized.
[0020]
Claim of this application 5 In the invention, the polishing treatment is performed with a fine polishing cloth of 800 mesh or more or a diamond grindstone of 4000 mesh or more. 4 The gist of the method is a method for producing a quartz glass crucible for pulling a silicon single crystal according to any one of the above.
[0021]
Claim of this application 6 In this invention, the arc melting is performed while reducing the pressure from the outer peripheral surface side of the crucible-shaped molded body, and before the end of the arc melting, hydrogen gas is supplied to the hollow portion of the crucible-shaped molded body to perform the arc melting. Claims 1 to characterized in that 5 The gist of the method is a method for producing a quartz glass crucible for pulling a silicon single crystal according to any one of the above.
[0022]
Claim of this application 7 According to the invention, the decompression is reduced or stopped before the supply of the hydrogen gas is started. 6 The manufacturing method of the silica glass crucible for pulling up a silicon single crystal described in 1) is summarized.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a method for producing a quartz glass crucible for pulling a silicon single crystal according to the present invention will be described with reference to the accompanying drawings.
[0024]
As shown in FIG. 1, a quartz glass crucible for pulling a silicon single crystal according to the present invention includes a melting crucible manufacturing process for manufacturing a melting crucible from a quartz raw material powder, a polishing process for polishing the inner surface of the melting crucible, And a heat treatment process for heat-treating the polished inner surface. In addition, when a fine foam layer of about 1 mm remains on the surface layer of the transparent layer, a grinding process for grinding (roughing) removing the foam layer is interposed between the melting crucible manufacturing process and the polishing process. Is preferred.
[0025]
First, the molten crucible manufacturing process is performed using, for example, a quartz glass crucible manufacturing apparatus as shown in FIG.
[0026]
The crucible molding die 2 of the quartz glass crucible manufacturing apparatus 1 includes an inner member 3 made of a gas permeable member such as a die having a plurality of through holes or a highly purified porous carbon die. The holding member 5 is provided with a ventilation portion 4 on the outer periphery thereof and holding the inner member 3. A rotating shaft 6 connected to a rotating means (not shown) is fixed to the lower portion of the holding body 5, and supports the crucible forming die 2 so as to be rotatable. The ventilation part 4 is connected to an exhaust port 8 provided in the center of the rotary shaft 6 through an opening 7 provided in the lower part of the holding body 5, and the ventilation part 4 is connected to a decompression mechanism 9. Has been.
[0027]
An arc electrode 10 for arc discharge, a raw material supply nozzle 11, an inert gas supply pipe 12 and a hydrogen gas supply pipe 13 are provided on the upper part facing the inner member 3.
[0028]
Therefore, in order to manufacture a melting crucible using the quartz glass crucible manufacturing apparatus 1, the crucible molding die 2 is moved by operating a rotary drive source (not shown) and rotating the rotary shaft 6 in the direction of the arrow. Rotate at a predetermined speed. In the crucible molding die 2, high-purity silica powder is supplied from above by a raw material supply nozzle 11. The supplied silica powder is pressed against the inner surface member 3 side of the crucible molding die 2 by centrifugal force and is formed into a crucible-shaped molded body R. ₁ Formed as.
[0029]
Next, along the manufacturing process diagram as shown in FIG. 3, the inside member 3 is depressurized by the operation of the depressurization mechanism 9, and further helium gas or argon gas, for example, helium gas is fixed from the inert gas supply pipe 12. Molded body R at a rate of quantity, for example 80 l / min ₁ Hollow part R _1i To supply. 5 minutes after supplying the helium gas, the arc electrode 10 was energized and continued, and the compact R ₁ Heated from the inside of the molded body R ₁ Inner surface R _1S A molten layer is formed.
[0030]
After a predetermined time has elapsed, in order to appropriately form an opaque layer containing many bubbles on the outside of the quartz glass crucible, the decompression mechanism 9 is adjusted or stopped to adjust or stop the decompression in the crucible molding die 2. The arc is continued for a total arc melting time of T minutes with the reduced pressure reduced or stopped, the helium gas supply is stopped after a certain time has elapsed from the start of arc melting, and the helium gas supply is stopped. Forming the hydrogen gas from the gas supply pipe 13 at a constant rate, for example, 100 liters / minute, R ₁ Hollow part R _1i To supply. The supply of hydrogen gas is started at least 5 minutes before, for example, 10 minutes before the end of arc melting, and after the elapse of time t corresponding to 40% of the total arc melting time T (t> 0. 4T). After a predetermined time T has elapsed from the start of arc melting, the arc energization is stopped, the supply of hydrogen gas is stopped, and the melting crucible manufacturing process ends.
[0031]
In the melting crucible manufacturing process described above, by supplying helium gas, as shown in FIG. 4, the amount of bubbles contained in the seed layer (inner surface) formed in the quartz glass crucible R at the beginning of melting and the outer opaque layer is appropriately set. Furthermore, by supplying helium gas and hydrogen gas in the latter half of the manufacturing process, the amount of bubbles in the transparent layer can be significantly reduced. Further, it is possible to prevent bubbles remaining in the transparent layer and bubbles in the opaque layer from expanding during pulling of the silicon single crystal.
[0032]
Furthermore, the amount of bubbles remaining in the transparent layer can be reduced by melting under reduced pressure, and the seed layer acts as a kind of ventilation wall, and the amount of bubbles in the opaque layer can be adjusted by adjusting the degree of pressure reduction. And the bubble diameter can be controlled. In order to obtain the former effect, the decompression melting is preferably started before or simultaneously with the start of the arc melting or after the inner surface of the crucible-shaped formed body is melted by arc melting, for example, 100 μm. Further, the amount of bubbles in the opaque layer can be controlled more appropriately by reducing or stopping the decompression during arc melting.
[0033]
Furthermore, since the supply of hydrogen gas starts 5 minutes before the arc melting is stopped, the effect of hydrogen supply is sufficiently obtained, the amount of bubbles remaining in the transparent layer inside the crucible is reduced, and the bubbles in the outer opaque layer are expanded. Can be prevented.
[0034]
In addition, since the supply of hydrogen gas is performed after a time t corresponding to 40% of the total arc melting time T, the high temperature viscosity of the fused crucible quartz glass is not lowered, and it can be used for a long time. A quartz glass crucible is obtained.
[0035]
As shown in FIG. 5, the hollow portion R of the melting crucible R while reducing the pressure. _1i When hydrogen gas is allowed to flow through the _1i From above to the unmelted layer R of the melting crucible R _u As the result, the viscosity of the entire quartz glass crucible is likely to be lowered. It is preferably stopped or reduced.
[0036]
Next, according to the process as shown in FIG. 1, the molten crucible manufactured as described above is ground in the grinding process.
[0037]
This grinding process is performed in two stages, a rough grinding process and a regrinding process, using a process as shown in the upper part of FIG. 6 and a handy type grinding apparatus (belt sander) 21 as shown in FIG.
[0038]
The grinding device 21 includes a vane-type rotating mechanism 23 that is rotated by high-pressure air sent from a high-pressure air pipe 22 that is communicated with an air compressor (not shown), and a drive rotation that is rotated by the vane-type rotating mechanism 23. A roller 24, a driven rotary roller 25 driven by the rotation of the drive rotary roller 24, a grinding belt 26 rotatably provided between the rotary rollers 24, 25, and the grinding belt 26 and the driven belt for performing wet grinding. A water supply nozzle 28 connected to a water supply pipe 27 for supplying water between the polished objects is provided.
[0039]
The grinding belt 26 is a diamond grindstone (belt), and the diamond particle size in the rough grinding process is made finer than 80 mesh (#).
[0040]
This grinding belt 26 is used as the inner surface R of the melting crucible R. _S The high pressure air pipe 22 is sent to the vane type rotating mechanism 23, the vane type rotating mechanism 23 is rotated, the drive rotating roller 24 is rotated, the grinding belt 26 is rotated, and the inner surface R _S To polish. At this time, the grinding belt 26 and the inner surface R through the water supply pipe 27 and the water supply nozzle 28. _S Since water is supplied in between, it becomes wet polishing, and it is ground quickly and highly flatly.
[0041]
In the regrinding process, the diamond particle diameter of the grinding belt 26 is made finer than 200 mesh, preferably 3000 mesh, and the arithmetic average roughness (Ra) (JIS B0601-1994) of the inner surface after the regrinding process is 3 μm or less. To flatten.
[0042]
In this way, by making the roughness of Ra 3 μm or less, it becomes possible to perform a quicker polishing process in the next process, and it is possible to reliably remove microcrack damage generated in the grinding process in a shorter time. It becomes like this.
[0043]
Further, according to the process shown in FIG. 1, the ground inner surface of the melting crucible is polished in the polishing process.
[0044]
For example, as shown in FIG. 8, the polishing process is performed using a handy type polishing apparatus 31. The polishing apparatus 31 includes a vane-type rotating mechanism 33 that is rotated by high-pressure air sent from a high-pressure air pipe 32 that is communicated with an air compressor (not shown), and a driving rotation that is rotated by the vane-type rotating mechanism 33. A roller 34, a polishing cloth 35 provided on the driving rotary roller 34, and a supply nozzle 37 connected to a supply pipe 36 for supplying an abrasive between the polishing cloth 35 and an object to be polished for wet polishing. Have.
[0045]
This polishing cloth 35 is used as the inner surface R of the melting crucible R. _S The high pressure air pipe 32 is sent to the vane type rotating mechanism 33, the vane type rotating mechanism 33 is rotated, the drive rotating roller 34 is rotated, the polishing cloth 35 is rotated, and the inner surface R is rotated. _S To polish. At this time, the polishing pad 35 and the inner surface R through the supply pipe 36 and the supply nozzle 37. _S Since an abrasive is supplied between them, wet polishing is performed, and polishing is performed with high flatness.
[0046]
Inner surface R polished as described above _S Ra can be 1 μm or less, and the variation in surface roughness can be within the range of ± 0.1 μm over the entire inner surface. Since the abrasive cloth 35 has a fine diamond particle size of 800 mesh or more, microcrack damage that is harmful to the inner surface can be more reliably removed, and the uniformity is higher and Ra is more surely less than 1 μm. Can be small. Furthermore, the state of the inner surface is more preferably a maximum height (Ry) (JIS B0601-1994) of 5 μm. In this case, higher uniformity of the inner surface is obtained.
[0047]
When Ra is set to 1 μm or less as described above, the heat treatment in the next process does not leave visible irregularities on the inner surface Rs and does not adversely affect the pulled silicon single crystal. Furthermore, it is possible to avoid leaving microcrack damage. If Ra exceeds 1 μm, the inner surface R of the crucible R even if the next heat treatment is performed. _S As a result, undulations that are visible to the eye remain, and it is easy to adversely affect the pulled silicon single crystal.
[0048]
Further, when the partial Ra variation of the inner surface Rs is within a range of ± 0.1 μm over the entire inner surface, the uniformity of the thickness of the glass layer formed by the heat treatment can be maintained. When the variation of Ra exceeds ± 0.1 μm, the uniformity of the thickness of the glass layer formed by the heat treatment is impaired due to the difference in the roughness state.
[0049]
When the polished inner surface Rs is 0.1 μm or less in Ra and the variation in Ra is ± 0.03 μm, the reliability of the above effect can be further improved.
[0050]
The grinding process is not limited to grinding with a diamond grindstone as shown in the upper part of FIG. 6, but is generally used wet sand blasting as shown in the lower part of FIG. Is performed by spraying fine SiC abrasive grains of 180 mesh or more with an aqueous solution having a volume conversion concentration of 10 to 40%. Further, the inner surface R is polished using the polishing cloth 35 in the same manner as described above. _S Ra is 1 μm or less.
[0051]
Sand blast grinding can reduce the grinding time by about 25% compared to diamond grinding. However, since sand blast grinding uses SiC abrasive grains, metal impurities and abrasive grains are likely to adhere to the grinding surface. After re-grinding using a fine diamond grindstone of 1000 mesh or more, similar polishing is performed, and the inner surface R _S Is preferably set to 1 μm or less in terms of Ra. Further, the sand blasting is not limited to wet, and may be dry. By using sand blasting, quick and highly flat grinding can be performed.
[0052]
Further, in the polishing step, a diamond grindstone having a fineness of 4000 mesh or more may be used without using a polishing cloth as described above, and in this case, the polished surface can be made 1 μm or less in Ra.
[0053]
Next, according to a process as shown in FIG. 1, the polished inner surface of the molten crucible is heat-treated by a heat treatment process.
[0054]
This heat treatment step (not shown) is performed by heating the entire inner surface using an oxyhydrogen burner. Even when microbubbles exist only on a part of the inner surface of the melting crucible, the entire inner surface is ground and polished in the grinding process and polishing process, and the entire inner surface is heated at high temperature using an oxyhydrogen burner. , SiO ₂ Vaporization does not occur, crystallization does not occur partially, and peeling of the inner surface does not occur when the silicon single crystal is pulled.
[0055]
The heat treatment with an arc flame has a considerably higher atmospheric temperature than the heat treatment with an oxyhydrogen burner. ₂ Evaporate this SiO 2 ₂ Impurities such as Al and Ca having a lower vapor pressure remain concentrated on the inner surface, and impurities such as Al and Ca are scattered on the inner surface of the crucible after the heat treatment.
[0056]
Also, if there are local protrusions and foreign matter, and these are removed by local grinding and then this removed part is heated locally to become vitrified, even if it is an oxyhydrogen burner, In comparison, the outer peripheral portion is in a relatively low temperature state, and in this outer peripheral portion, SiO ₂ Vaporization occurs, solidifies and adheres to the inner surface, leaving a rough surface. This rough portion may be crystallized and peeled when the silicon single crystal is pulled, leading to a decrease in the single crystallization rate.
[0057]
As described above, the method for producing a quartz glass crucible is to produce a melting crucible by arc melting a crucible-shaped body of quartz raw material powder formed in a mold, and if necessary, grind the entire inner surface of this melting crucible, Further, the entire inner surface is polished, and the polished inner surface is heat-treated with an oxyhydrogen burner. The silica glass crucible can be made bubble-free and the purity of the inner surface can be improved. A method for producing a silica glass crucible that can improve the pulling yield can be provided by pulling up the silicon single crystal using.
[0058]
【Example】
Test 1: A quartz glass crucible having a diameter of 22 inches manufactured using the method for manufacturing a silica glass crucible according to the present invention (Example 1) and a quartz glass crucible manufactured by a conventional manufacturing method by ordinary vacuum melting (Conventional Example 1) ), Each sample was cut out, the state of bubbles on the inner surface was measured using an optical microscope, and the purity was measured by atomic absorption spectroscopy (frameless method). Further, using each quartz glass crucible, an 8-inch P-type silicon single crystal was pulled up.
[0059]
Results: Example 1: It was confirmed that no fine bubbles were present on the inner surface and the purity was improved as compared with Conventional Example 1. The single crystallization rate at the time of pulling was 100%, and it was confirmed that there were no bubbles near the inner surface of the quartz glass crucible after use.
[0060]
Conventional Example 1: Microbubbles remained in the vicinity of the inner surface, and it was confirmed that the purity was inferior to that of Example 1. The single crystallization rate at the time of pulling was 85%, and many irregularities were observed near the inner surface of the quartz glass crucible after use.
[0061]
【The invention's effect】
According to the method for producing a silica glass crucible for pulling a silicon single crystal according to the present invention, even if the silicon single crystal is pulled, no bubbles are taken in the pulled single crystal, no dislocation occurs, It is possible to provide a method for producing a quartz glass crucible for pulling a silicon single crystal that can obtain a crystallization rate.
[0062]
That is, a quartz glass crucible in which quartz raw material powder is supplied into a rotating mold to form a crucible-shaped body and the entire inner surface of a molten crucible obtained by arc melting is polished, and the polished surface is heated by an oxyhydrogen burner. Therefore, it is possible to provide a method for producing a silica glass crucible that can eliminate the bubbles on the inner surface of the quartz glass crucible, improve the purity of the inner surface, and improve the yield of pulling up the silicon single crystal.
[0063]
In addition, since the surface roughness of the polished surface is adjusted to 1 μm or less by arithmetic mean roughness (Ra), by performing the heat treatment in the next step, there is no visible unevenness on the inner surface of the crucible, The silicon single crystal to be pulled is not adversely affected, and further, no microcrack damage is left.
[0064]
In addition, since the variation of the polished surface is within the range of ± 0.1 for Ra in the entire inner surface of the melting crucible, the uniformity of the thickness of the glass layer formed by the heat treatment can be maintained.
[0065]
In addition, since the entire inner surface of the melting crucible is ground to 3 μm or less with Ra before the polishing process, it becomes possible to perform a quicker polishing process in the next polishing process, and moreover, the microcrack damage that occurs in the grinding process is ensured. And it can be removed in a shorter time.
[0066]
Further, since the grinding is performed using a diamond grindstone having a diamond particle diameter of 80 mesh or more, grinding can be performed quickly and highly flatly.
[0067]
In addition, since the grinding is performed by sandblasting using abrasive grains having a particle diameter of 90 mesh or more, quick and highly flat grinding can be performed.
[0068]
In addition, after grinding, re-grinding is performed using a diamond grindstone with a diamond particle size of 200 mesh or more, so that Ra can be quickly reduced to a roughness of 3 μm or less, and further, the micro-particles generated in the rough grinding process can be reduced. Crack damage can be removed reliably and in a shorter time.
[0069]
In addition, since the polishing process is performed with a fine polishing cloth of 800 mesh or more or a diamond grindstone of 4000 mesh or more, the microcrack damage that is harmful to the inner surface can be more reliably removed, and the uniformity is further improved. And Ra can be made smaller than 1 μm more reliably.
[0070]
In addition, a quartz glass crucible in which arc melting is performed while reducing the pressure from the outer peripheral surface side of the crucible-shaped molded body, and hydrogen gas is supplied to the hollow portion of the crucible-shaped molded body before the end of the arc melting to perform arc melting. Since it is a manufacturing method, the effect of hydrogen supply can be sufficiently obtained, the amount of bubbles remaining in the transparent layer inside the crucible can be reduced, and the bubbles in the outer opaque layer can be prevented from expanding.
[0071]
In addition, since the quartz glass crucible is produced by reducing or stopping the decompression before the supply of hydrogen gas is started, the quartz glass can withstand long-term use without reducing the high temperature viscosity of the quartz glass crucible. A crucible is obtained.
[Brief description of the drawings]
FIG. 1 is a process diagram of a method for producing a quartz glass crucible for pulling a silicon single crystal according to the present invention.
FIG. 2 is a conceptual diagram of a quartz glass crucible manufacturing apparatus used in a method for manufacturing a quartz glass crucible for pulling a silicon single crystal according to the present invention.
FIG. 3 is an explanatory diagram of a melting crucible manufacturing process of a method for manufacturing a quartz glass crucible according to the present invention.
FIG. 4 is an explanatory view of a quartz glass crucible manufactured in a melting crucible manufacturing process of a manufacturing method of a silica glass crucible according to the present invention.
FIG. 5 is an explanatory view of the state of the quartz glass crucible in the melting crucible manufacturing process of the method for manufacturing the silica glass crucible according to the present invention.
FIG. 6 is a flowchart of a grinding process and a polishing process in the method for producing a quartz glass crucible according to the present invention.
FIG. 7 is an explanatory view of a grinding apparatus used in a grinding process of a method for producing a quartz glass crucible according to the present invention.
FIG. 8 is an explanatory view of a polishing apparatus used in the polishing step of the method for manufacturing a quartz glass crucible according to the present invention.
[Explanation of symbols]
1 Quartz glass crucible production equipment
2 Mold for crucible molding
3 Inner member
4 Ventilation part
5 Holder
6 Rotating shaft
7 opening
8 Exhaust vent
9 Pressure reducing mechanism
10 Arc electrode
11 Raw material supply nozzle
12 Inert gas supply pipe
13 Hydrogen gas supply pipe
21 Grinding device (belt sander)
22 High pressure air pipe
23 Vane type rotating mechanism
24 Drive rotation roller
25 driven rotating roller
26 Grinding belt
27 Water supply pipe
28 Water supply nozzle
31 Polishing equipment
32 High pressure air pipe
33 Vane type rotating mechanism
34 Drive rotation roller
35 Abrasive cloth
36 Supply pipe
37 Supply nozzle
R Molten crucible (quartz glass crucible)
R ₁ Compact
R _1i Hollow part
Rs inner surface
R _u Unmelted layer

Claims (7)

For pulling a silicon single crystal by supplying quartz raw material powder into a rotating mold to form a crucible-shaped body and polishing the entire inner surface of the melted crucible, and then heat-treating this polished surface with an oxyhydrogen burner A method for producing a quartz glass crucible for pulling a silicon single crystal, wherein the entire inner surface of a molten crucible is ground to 3 μm or less with Ra before the polishing treatment . 2. The method for producing a quartz glass crucible for pulling a silicon single crystal according to claim 1 , wherein the grinding is performed using a diamond grindstone having a diamond particle size of 80 mesh or more. The method for producing a quartz glass crucible for pulling a silicon single crystal according to claim 1 , wherein the grinding is performed by sandblasting using abrasive grains having a grain size of 90 mesh or more. After the grinding, the method for manufacturing a silicon single crystal for pulling up the quartz glass crucible according to claim 2 or 3 the particle size of the diamond particles and performs the re-grinding with a fine diamond wheel 200 meshes or more. The method for producing a quartz glass crucible for pulling a silicon single crystal according to any one of claims 1 to 4 , wherein the polishing treatment is performed with a fine polishing cloth of 800 mesh or more or a diamond grindstone of 4000 mesh or more. The arc melting is performed while reducing the pressure from the outer peripheral surface side of the crucible-shaped formed body, and before the end of the arc melting, hydrogen gas is supplied to the hollow portion of the crucible-shaped formed body to perform the arc melting. A method for producing a quartz glass crucible for pulling a silicon single crystal according to any one of claims 1 to 5 . The method for producing a quartz glass crucible for pulling a silicon single crystal according to claim 6 , wherein the reduced pressure is reduced or stopped before the supply of the hydrogen gas is started.

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