KR101174812B1 - Quartz glass crucible for pulling silicon single crystal and method for producing the same - Google Patents

Abstract

The present invention provides a synthetic quartz glass crucible capable of raising silicon single crystals in high yield without generating dielectric breakdown due to vibration of the melt surface and peeling of quartz glass pieces, and a method of manufacturing the same.

An opaque quartz glass crucible base outer layer having a bottom, a bend and a sidewall; A quartz glass crucible for pulling up a silicon single crystal having a quartz glass crucible base formed on an inner surface side of the outer layer of the crucible base and having a quartz glass crucible base layer having a bottom, a curved part and a sidewall part, wherein the bottom part and the sidewall part of the inner layer of the crucible base are formed. 0.5 mm or more and 4.0 mm or less thickness region from the inner surface and 0.5 mm or more and 10.0 mm thickness region from the inner surface of the curved portion of the inner surface of the crucible base are formed of synthetic quartz glass, and the inner surface in the inner surface of the crucible body to 0.5mm or more, the organic fabric area in which the thickness of the area of less than 2mm in diameter containing more than 10μm, or less bubbles of 100μm or less 10 gae / mm ³ or more, to 200 / mm ³ was formed from.

 Silicon, single crystal, quartz glass, crucible, practical inorganic fabric layer, carbon electrode, stirring blade shaft, metering control valve, nozzle, pressure reducing pump

Description

Quartz glass crucible for pulling silicon single crystal and its manufacturing method {Quartz glass crucible for pulling silicon single crystal and method for producing the same}

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows 1st Embodiment of the quartz glass crucible for silicon single crystal pulling of this invention.

It is sectional explanatory drawing which shows 2nd Embodiment of the quartz glass crucible for silicon single crystal pulling of this invention.

3 is an explanatory cross-sectional view showing a third embodiment of the quartz glass crucible for pulling a silicon single crystal of the present invention.

Fig. 4 is a schematic cross-sectional view showing an embodiment of an apparatus for manufacturing a quartz crucible for pulling a silicon single crystal of the present invention.

Explanation of sign

3: crucible gas outer layer, 4: crucible gas inner layer, 14: substantially inorganic cloth layer, 10: power source, 51: carbon electrode, 71: cover, 75: slit opening, 75: annular slit opening, 91: stirring blade shaft, 92: Metering control valve, 93: Nozzle, P: Pressure reducing pump.

The present invention relates to a quartz glass crucible used for pulling a silicon single crystal and a method for producing the same.

Conventionally, the so-called Czochralski method (CZ method) is widely used for the production of silicon single crystals. This CZ method is to grow cylindrical silicon single crystals by melting silicon polycrystals as raw materials in a quartz glass crucible, immersing silicon single crystal seed crystals in this melt, and raising seed crystals while rotating quartz crucibles and seed crystals. .

In this CZ method, in recent years, synthetic quartz glass crucibles have been mainly used due to the large diameter of crystals and the prolonged process time. Generally, a quartz glass crucible is comprised by the dual structure of an opaque outer layer (a crucible base) which contains a bubble free inner layer and a bubble substantially, and is the same also in a synthetic quartz glass crucible.

The term "synthetic quartz glass crucible" means that only the inner layer or the whole crucible is formed of synthetic quartz glass and the crucible gas other than that is formed of natural quartz glass.

It is thought that the defect which arises in the whole pulling process using this synthetic quartz glass crucible is mainly caused by the vibration which generate | occur | produces on the melt surface when melting a silicon single crystal. In this case, the vibration generated at the surface of the melt at the beginning of the process is negligible in the natural quartz glass crucible, but in the synthetic quartz glass crucible, the amplitude of the vibration tends to be large, causing seeding defects.

In order to solve this problem, the present inventors use natural quartz glass crucible to make a part of the inner layer of the crucible with natural quartz glass, and the inner layer of the other part with synthetic quartz glass by using the characteristic that the vibration occurring on the melt surface is small. Has proposed a method of suppressing vibration (Patent Document 1). However, impurity contained in the inner layer of natural quartz glass contaminated the silicon single crystal as compared with the general synthetic quartz glass crucible, which has been unacceptable to some silicon single crystal impression manufacturers, which have strict purity requirements.

Moreover, the main cause of the defect which arises in the latter half of a process is peeling of a quartz piece in the crucible inner surface. Quartz glass crucibles generally contain no bubbles and contain a transparent inner layer and bubbles, making them a double structure of opaque crucible gas. Expansion and rupture cause peeling of the inner surface of the crucible. When this peeled quartz piece adheres to the pulling single crystal, a transition occurs at that portion, which significantly lowers the yield.

In order to solve this problem, the present inventors suppress bubble expansion within 1 mm of the inner surface of the crucible after pulling up the silicon single crystal (Patent Document 2), or introduce water vapor into the crucible gas in the inner layer forming process of the quartz glass crucible (patent) Document 3) has been proposed to substantially eliminate bubbles within 1 mm from the surface of all inner layers of the synthetic quartz glass crucible. However, in this process, there is a drawback that vibrations occurring at the surface of the melt at the initial stage are frequently prone to seed failure.

[Patent Document 1] Japanese Patent Application Laid-Open No. 2004-59410

[Patent Document 2] Japanese Patent Application Laid-Open No. 2000-44386

[Patent Document 3] Japanese Patent Application Laid-Open No. 2001-348240

[Patent Document 4] Japanese Patent Laid-Open No. 4-228611

In view of such a phenomenon, the present inventors have intensively studied, and as a result, the present inventors have found that a part of the inner layer of the synthetic quartz glass crucible has a predetermined diameter in a certain range of amount (density) in the amount of the peeled quartz piece. It was found out that initial problems such as poor seeding can be reduced by suppressing vibration of the melt at the beginning of the process so as not to cause a decrease in yield. That is, an object of the present invention is to provide a synthetic quartz glass crucible capable of raising the silicon single crystal with high yield without generating dielectric breakdown due to vibration of the melt surface and peeling of the quartz glass piece, and a method of manufacturing the same. do.

In order to solve the above problems, the silicon single crystal pulling quartz glass crucible of the present invention is formed on an inner surface side of an opaque quartz glass crucible base layer having a bottom portion, a curved portion and a side wall portion, and is formed on the inner surface side of the crucible base outer layer and further has a bottom portion, a curved portion and a side wall. A quartz glass crucible for pulling a single crystal of silicon having a quartz glass crucible base composed of an inner layer of a quartz glass crucible base having a portion, the region having a thickness of 0.5 mm or more and 4.0 mm or less from the inner surface of the bottom and sidewall portions of the crucible base inner layer and the crucible An area of 0.5 mm or more and 10.0 mm or less thick is formed of synthetic quartz glass from the inner surface of the curved portion of the gas inner layer, while bubbles of 10 μm or more in diameter and 60 μm or less are formed in the sidewall portion within 2 mm from the inner surface of the crucible gas inner layer. Forming a bubble area containing 75 pieces / mm ³ , or at least 10 μm in diameter at the side wall; Forming the bubbles of 70μm or less 90 / mm ³ containing the bubble region, or even at the bottom diameter of 10μm or more, the air bubbles of less than 40μm to form a 50 / mm ³ containing the bubble region, or at the bottom diameter of 2μm or more, The bubble area | region containing 50 pieces / mm <^3> of 40 micrometers or less bubbles, and 75 micrometers / mm <^3> of bubbles of 10 micrometers or more in diameter and 60 micrometers or less is formed also in the curved part and the side wall part.

When the thickness of the synthetic quartz glass layer formed on the inner surface of the inner surface of the crucible base is less than 0.5 mm, the quartz glass melts in the silicon melt during pulling up of the silicon single crystal, so that the opaque quartz glass layer appears, thereby significantly lowering the single crystallization rate. On the other hand, when the thickness of the synthetic quartz glass layer formed on the inner surface of the bottom and sidewall portions of the inner surface of the crucible body is more than 4.0 mm, the crucible to be produced becomes soft due to lack of viscosity in terms of heat resistance and furthermore, the productivity of crucible production And from the viewpoint of economics.

A substantially inorganic foam layer that is substantially free of bubbles is formed in a thickness area of 0.5 mm or more and 2 mm or less from an inner surface to cover a portion of the inner layer of the crucible body, and further, the bottom and sidewalls of the crucible body inner layer and the substantially inorganic foam layer. It is preferable that the thickness area of 0.5 mm or more and 4.0 mm or less from the inner surface of the part and the thickness area of 0.5 mm or more and 10.0 mm or less from the inner surface of the curved portion of the crucible base inner layer and the inorganic cloth area be formed of synthetic quartz glass.

The substantially inorganic cloth layer is preferably formed to cover the bottom and the curved portion of the inner layer of the crucible body or to cover the side wall and the curved portion of the inner layer of the crucible body.

It is preferable that the diameter of the bubbles existing in the crucible gas inner layer region within 0.5 mm from the inner surface of the crucible after pulling up the silicon single crystal is 150 µm or less.

According to a first aspect of the method for producing a silicon single crystal pulling quartz glass crucible of the present invention, a natural silica powder is filled along an inner circumferential surface of a rotating gas permeable mold, and the synthetic silica powder is a part of the inner surface of the natural silica powder compact. Or it is filled so as to cover the whole, during which the suction and exhaust through the wall of the mold while heating the melted layer of the natural and synthetic silica powder with an arc flame from the inner surface side, and during the suction through the wall of the mold A gas formation step of forming a crucible gas comprising an opaque quartz glass crucible base outer layer and a quartz glass crucible inner layer while evacuating, and at least 0.5 mm and 4.0 mm or less from the inner surfaces of the bottom and sidewall portions of the crucible base layer; 0.5mm or more and 10.0mm or less from the inner surface of the curved area of the thickness region of the crucible body To the area of this composite it is formed of a quartz glass, the furnace and the gas inner layer at least 10μm in diameter in the side wall portion within 2mm from the inner surface, forming a bubble zone containing cells of less than 60μm 75 gae / mm ^3, or at the side wall portions Forming a bubble region containing 90 / mm ³ of bubbles having a diameter of 10 μm or more and 70 μm or less, or forming a bubble region containing 50 / mm ³ of bubbles having a diameter of 10 μm or more and 40 μm or less at the bottom, or It is characterized by forming a bubble region containing 50 bubbles / mm ³ of bubbles having a diameter of 2 μm or more and 40 μm or less, and containing 75 bubbles / mm ³ of bubbles having a diameter of 10 μm or more and 60 μm or less in the curved portion and the side wall portion.

According to a second aspect of the method for producing a silicon single crystal quartz glass crucible of the present invention, a natural silica powder is filled along the inner circumferential surface of a rotating gas permeable mold, and the synthetic silica powder is a part of the inner surface of the natural silica powder compact. Or it is filled to cover the whole, during which the suction and exhaust through the wall of the mold while heating and melting the filler layer of the natural and synthetic silica powder from the inner surface side to the arc flame, and during the suction exhaust through the wall of the mold Forming a crucible gas consisting of an opaque quartz glass crucible base outer layer and a quartz glass crucible inner layer while conducting a gas formation step; an arc flame is formed inside the crucible gas simultaneously with or after the crucible gas is formed. To provide a synthetic silica powder in a hot gas atmosphere, It consists of a process of forming a substantially inorganic cell layer which forms a substantially inorganic cell layer which contains substantially no bubble by adhering and melting it to a surface, and it is 0.5 mm or more from the inner surface of the bottom and side wall part of a crucible body inner layer and a substantially inorganic cell layer. A thickness area of less than or equal to mm and a thickness area of greater than or equal to 0.5 mm and less than or equal to 10.0 mm from the inner surface of the crucible base inner layer and the curved portion of the substantially inorganic cloth layer are formed of synthetic quartz glass and within 2 mm from the inner surface of the crucible base layer. In the side wall portion, a bubble region containing 75 / mm ³ of bubbles having a diameter of 10 μm or more and 60 μm or less is formed, or a bubble region containing 90 / mm ³ of bubbles having a diameter of 10 μm or more and 70 μm or less is formed in the side wall portion. , or in the bottom diameter of 10μm or more, the air bubbles of 40μm or less 50 gae / mm ³ to form a cell-containing region, or more than 2μm in diameter at the bottom, 40 air bubbles below 50 m gae / mm ³ containing the loop portion and side wall portion in more than 10μm in diameter, to form a cell region containing the bubbles of 60μm or less 75 gae / mm ^3, and the substantially inorganic fabric layer is at least 0.5mm from the inner surface , Characterized in that the thickness area of less than 2mm is substantially an inorganic gun.

Further, the substantially inorganic cloth layer is preferably formed to cover the bottom and the curved portion of the inner layer of the crucible body or to cover the side wall and the curved portion of the inner layer of the crucible body.

EMBODIMENT OF THE INVENTION Although one Embodiment of this invention is described below based on an accompanying drawing, it cannot be overemphasized that various deformation | transformation is possible besides the example of illustration unless it deviates from the idea of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows 1st Embodiment of the quartz glass crucible for silicon single crystal pulling of this invention.

In Fig. 1, A ₁ is a first embodiment of the quartz glass crucible for pulling the silicon single crystal of the present invention, and has a base outer layer bottom portion 3a, a base layer outer curvature 3b, and a base layer side wall portion 3c. An opaque quartz glass layer crucible base outer layer 3 is provided. On the inner surface of the crucible gas outer layer 3, a quartz glass-layer crucible gas inner layer 4 is formed, which is composed of a gas inner layer bottom portion 4a, a gas inner layer curved portion 4b, and a gas inner layer side wall portion 4c. Crucible inner layer base 4 is provided with a 0.5mm or more, the organic Four regions containing no more than 10 bubbles having a diameter of more than 10μm, 100μm or less in thickness area of less than 2mm pieces / mm ³ or more, to 200 / mm ³ is formed from the inner surface have. The crucible base 3A is composed of a crucible base outer layer 3 and a crucible base inner layer 4. In Fig. 1, reference numeral 14 denotes a substantially inorganic foam layer that contains substantially no bubbles, and is formed in the crucible base inner layer 4 so as to cover a part of the crucible base inner layer 4. This substantially inorganic cloth layer 14 has a thickness area of 0.5 mm or more and 2 mm or less from its inner surface substantially free of bubbles. In the example of FIG. 1, the curved part 4b and the bottom part 4a of the gas inner layer 4 are covered with the substantially inorganic cloth layer 14a, and the side wall part 4c of the gas inner layer 4 is exposed.

A bottom inner layer composed of a gas inner layer bottom portion 4a and a substantially inorganic fabric layer 14a and an area of not less than 0.5 mm and not more than 4.0 mm from the inner surface of the gas inner layer side wall portion 4c and the gas layer curved portion 4b. 0.5 mm or more and 10.0 mm or less of thickness area | region is formed with the synthetic quartz glass from the inner surface of the curved part inner layer which consists of the inorganic cloth layer 14a.

As the quartz glass crucible for pulling the silicon single crystal of the present invention, various embodiments can be considered in addition to FIG. 1, and therefore, another embodiment will be described below. It is sectional explanatory drawing which shows 2nd Embodiment of the quartz glass crucible for silicon single crystal pulling of this invention. In Fig. 2, A ₂ is a second embodiment of the quartz glass crucible for pulling the silicon single crystal of the present invention. The basic configuration of having the crucible base 3A is the same as that of Fig. 1, but the substantially inorganic The arrangement is different from the case of FIG. 1. That is, the side wall part 4c and the curved part 4b of the gas inner layer 4 are covered with the substantially inorganic cloth layer 14b, and the bottom part 4a of the gas inner layer 4 is exposed.

3 is an explanatory cross-sectional view showing a third embodiment of the quartz glass crucible for pulling a silicon single crystal of the present invention. In Fig. 3, A ₃ is a third embodiment of a commercial quartz glass crucible which is a silicon single crystal of the present invention. The basic configuration of having a crucible base 3A is the same as that of Figs. It differs from FIG. 1 and FIG. 2 in that an inorganic cloth layer does not exist. In other words, the crucible base inner layer 4 is formed only of the organic cell region, and no substantial inorganic cell layer is formed.

As is apparent from the examples shown in Figs. 1 to 3, in the quartz glass crucible for pulling the silicon single crystal of the present invention, a substantial inorganic cell layer is formed in a part of the gas inner layer 4 having the organic cell region, or the organic cell region is formed. Only the gaseous inner layer 4 is formed.

Then, the apparatus for manufacturing the quartz glass crucible for pulling up the silicon single crystal of this invention is demonstrated with reference to FIG. 4 is a schematic cross-sectional view showing one embodiment of an apparatus for producing a quartz glass crucible for pulling a silicon single crystal of the present invention.

In FIG. 4, the rotary mold 1 has a rotary shaft 2. The cavity 1a is formed in the mold 1. In addition, a plurality of gas suction passages 1b are formed in the mold 1. The gas suction passage 1b passes through the passage 1c formed in the rotary shaft 2 and is connected to the pressure reducing pump P. As shown in FIG.

An opaque silica glass outer layer, that is, a crucible gas 3A, is formed and disposed in the cavity 1a. The gas 3A is introduced into the mold 1 by rotating the natural silica powder to form a layer along the inner wall of the mold 1, and then partially or the entire inner surface of the inner wall of the gas outer layer 3 formed of the natural silica powder. The synthetic silica powder was poured along the inner wall to form a layer, and later, the organic air bubble inner layer 4 was formed on the inner surface side of the gas outer layer 3 by suction exhaust and melting to form a desired crucible 3A. The preform is formed into a shape. The preform is heated from the inner surface to melt the silica powder, and then cooled.

As the heat source 5 for heating from the inner surface, an arc discharge device provided with the carbon electrodes 51 and 52 connected to the power source 10 can be used as shown in FIG. The manufacturing method of the crucible base 3 is described in detail in patent document 4. As shown in FIG.

In the manufacturing process of the crucible gas outer layer 3 and the organic gas base layer 4, the decompression pump P is operated to melt the gas outer layer 3 and the organic gas base layer 4 through the mold 1. The gas is drawn from the glass layer in the chamber. The degree of decompression increases gradually with the onset of heat melting because the silica powder melts when the heat melting starts and the air permeability decreases. The degree of decompression causes the indication in the suction passage to be raised by at least 250 mmHg from the indication before the start of heating melting. When only 250 mm Hg was increased at the indicated value before the start of hot melting, an organic cell base layer 4 containing less bubbles up to a depth of several mm was formed on the inner surface of the silica powder packing layer. In the process of manufacturing the crucible base 3A with the vacuum suction, the bubbles in the silica powder layer forming the crucible base 3A are sucked outward, whereby the content of the bubbles is reduced and the size of the bubbles is also reduced. As described above, it is possible to obtain an organic bubble gas inner layer 4 containing less air bubbles and a gas outer layer 3 containing a lot of bubbles by reducing the pressure so that the degree of decompression is at least 250 mmHg at the indicated value before the start of heating melting. It turned out. The time required for the decompression degree to rise only 250 mmHg from the indication before the start of heating melting is 90 to 210 seconds in the melting of the 22-inch and 24-inch crucibles.

During the production of the base 3A described above, after a predetermined time elapses, for example, 120 seconds after the start of heat melting of the inner surface, formation of the substantially synthetic synthetic glass inner layer 14a is started. For this reason, the apparatus shown in FIG. 4 is provided with the supply tank 9 of synthetic silica powder. The feed tank 9 has the stirring blade shaft 91, and the synthetic silica powder 6 of the quantity adjusted by the metering control valve 92 provided in the feed tank 9 is sent out through the nozzle 93. As shown in FIG. In the apparatus shown in Fig. 4, the nozzle 93 opens an inlet between the carbon electrodes 51 and 52 facing each other. The apparatus also has a lid 71 which covers the upper opening of the base 3, leaving a slit opening 75 around it. When the arc discharge is performed by the carbon electrodes 51 and 52 serving as the heat source 5 by covering the upper opening of the base 3 with the lid 71, the crucible base 3 and the organic cell base inner layer 4 Inside the hot gas atmosphere 8 is formed. The amount of the synthetic silica powder 6 adjusted by the nozzle 93 is supplied into this hot gas atmosphere 8. Synthetic silica powder (6) supplied with directivity to the hot gas atmosphere is melted by at least one part by the hot gas atmosphere, and thus is attached to only a part of the surface of the organic gas base layer (4) to be substantially inorganic. The glass inner layer 14a is formed. The hot gas flows out like an arrow from the annular slit opening 75 between the gas 3A and the lid 71. The substantial inorganic cloth inner layer 14a formed by this method has an extremely low inclusion rate. No bubbles are visible to the naked eye, and even if observed using an optical microscope, the diameter is less than 10 / mm ³ that is larger than 20 μm. It is necessary to form the substantially inorganic cloth inner layer 14a formed by this method to a thickness of at least 0.5 mm. Preferable thickness is 0.8 mm or more, More preferably, thickness is 1.0 mm or more.

Example

Although an Example is given to the following and this invention is demonstrated to it concretely, this invention is not limited to this.

Example 1

Using a device having the same structure as that shown in Fig. 4, a synthetic quartz crucible having a diameter of 22 inches was made by the following procedure. While carrying out suction exhaust in the same manner as described above, natural silica powder having a diameter of 50 µm or more and 300 µm or less was supplied into a rotating mold to form a molded body having a powder layer of 25 mm in thickness. Then, the powder layer of thickness 4mm was formed in the side wall part and the curved part of the said molded object from the inside of the molded object rotated with the synthetic silica powder of 50 micrometers or more and 300 micrometers or less in diameter. While the suction exhaust was continued, heat melting was started from the inside of the molded body of the natural and synthetic silica powder by arc discharge, and the amount of arc heat was raised to 1000 kw for 2 minutes. Again, melting was continued while maintaining the arc calorific value at 1000 kw for 1 minute. In the meantime, the suction exhaust was continued and the suction exhaust was stopped at the time when 250 torr was increased from the decompression degree at the start of melting. After 3 minutes from the start of melting, the amount of arc heat was lowered to 300 kW while maintaining the arc discharge, and the total amount of 700 g of the synthetic silica powder was supplied at 140 g / min for 5 minutes to the high temperature atmosphere formed inside the molded body, and the inside of the curved part and the bottom part was supplied. A 0.8 mm thick transparent synthetic quartz glass layer was formed on the surface layer to form a first synthetic quartz crucible having a diameter of 22 inches.

The first synthetic quartz crucible was broken, and the side wall, curvature and bottom of the crucible were taken and sliced thinly in parallel to the inner surface direction and subjected to wet chemical analysis by ICP-MS. As a result, the surface of the inner surface layer of the side wall of the crucible gas was found. From 2mm to 2mm was the synthetic quartz glass layer, 8mm from the surface of the inner surface layer at the curved part, and 1mm from the surface at the bottom was the synthetic quartz glass layer. Again, 3mm-thick sample fragments were made in the cross-sectional direction of the side wall, the curved portion, and the bottom, and the bubbles were observed with an optical microscope.In the side wall sample, 75 bubbles having a diameter of 10 μm or more and 60 μm or less within 2 mm from the surface thereof. mm ^{3 was} observed and no bubbles were found within 0.8 mm from each surface at the bend and bottom.

A second synthetic quartz crucible was made in the same manner as the first synthetic quartz crucible. Using this second synthetic quartz glass crucible, the pulling up of the silicon single crystal was carried out under reduced pressure. As a result, the surface of the silicon melt could not be vibrated and could be seeded smoothly without dislocations occurring during the pulling. It was possible to raise the complete silicon single crystal. As a result of observing the inner surface layer of the synthetic quartz crucible after use, all the bubbles which exist within 0.5 mm from the inner surface of an inner surface layer were 150 micrometers or less.

Example 2

2.5 minutes after the start of melting while the arc calorific value was raised to 900 kw for 2.5 minutes and the arc calorific value was maintained at 1000 kw for 1 minute, after 3.5 minutes from the start of melting, the arc calorific value was lowered to 300 kw while maintaining the arc discharge and synthesized in a high temperature atmosphere. The first synthetic quartz having a diameter of 22 inches in the same manner as in Example 1, except that a total of 900 g of silica powder was supplied at 150 g / min for 6 minutes and a transparent synthetic quartz glass layer having a thickness of 1 mm was formed on the inner surface of the curved portion and the bottom portion. I made a crucible.

The first synthetic quartz crucible was destroyed in the same manner as in Example 1, and the same chemical analysis was conducted. As a result, up to 3 mm from the surface of the inner surface layer of the side wall portion of the crucible gas was the synthetic quartz glass layer. At 10 mm and the bottom, 1 mm was the synthetic quartz glass layer from the surface. Again, as in Example 1, sample fragments were made and bubbles were observed. As a result, in the side wall sample, bubbles having a diameter of 10 μm or more and 70 μm or less were observed within 90 mm / mm ³ within 2 mm from the surface thereof. Bubbles could not be confirmed within 1 mm from the surface.

A second synthetic quartz crucible was made in the same manner as the first synthetic quartz crucible. As a result of pulling up the silicon single crystal in the same manner as in Example 1 using this second synthetic quartz glass crucible, it was possible to raise the complete silicon single crystal in the same manner as in Example 1. The observation result of the inner surface of the synthetic quartz crucible after use was also the same as that of Example 1.

Example 3

The first synthetic quartz crucible having a diameter of 22 inches was formed in the same manner as in Example 1 except that a powder layer having a thickness of 6 mm was formed at the bottom of the molded body and a transparent synthetic quartz glass layer having a thickness of 0.8 mm was formed at the inner surface of the side wall portion. made.

The first synthetic quartz crucible was destroyed in the same manner as in Example 1, and as a result of the same chemical analysis, up to 0.8 mm from the surface of the inner surface layer of the side wall portion of the crucible gas was the synthetic quartz glass layer, and the curved portion was the surface of the inner surface layer. 10 mm from the bottom and 2 mm from the surface at the bottom were synthetic quartz glass layers. In the same manner as in Example 1, the sample fragments were made and bubbles were observed. In the bottom sample, bubbles having a diameter of 10 μm or more and 40 μm or less were observed within 50 mm / mm ³ within 2 mm of the bottom sample, and 0.8 from the surface of the curved and side wall portions, respectively. Bubbles could not be confirmed within mm.

A second synthetic quartz crucible was made in the same manner as the first synthetic quartz crucible. As a result of pulling the silicon single crystal in the same manner as in Example 1 using the second synthetic quartz glass crucible, it was possible to raise the complete silicon single crystal in the same manner as in Example 1. The observation result of the inner surface of the synthetic quartz crucible after use was also the same as that of Example 1.

Example 4

Example 1 except that a powder layer having a thickness of 4 mm was formed on the inner surface of the molded body, and the amount of arc heat was lowered to 400 kW while maintaining arc discharge for 3 minutes from the start of melting. In the same manner as the first synthetic quartz crucible of 22 inches in diameter was made.

The first synthetic quartz crucible was destroyed in the same manner as in Example 1, and as a result of the same chemical analysis, up to 2 mm from the surface of the inner surface layer of the side wall portion of the crucible gas was the synthetic quartz glass layer. At 10 mm and the bottom, 1 mm was the synthetic quartz glass layer from the surface. In the same manner as in Example 1, the sample fragments were made and bubbles were observed. In the bottom sample, bubbles having a diameter of 2 μm or more and 40 μm or less were observed within 50 mm / mm ³ within 2 mm from the surface, and 2 mm from the surface in the curved and side wall portions, respectively. Within 75 micrometers / mm <^3> of bubbles of 10 micrometers or more and 60 micrometers or less in diameter were observed within them.

A second synthetic quartz crucible was made in the same manner as the first synthetic quartz crucible. As a result of pulling the silicon single crystal in the same manner as in Example 1 using the second synthetic quartz glass crucible, it was possible to raise the complete silicon single crystal in the same manner as in Example 1. The observation result of the inner surface of the synthetic quartz crucible after use was also the same as that of Example 1.

Comparative Example 1

Using the same apparatus as in Example, a synthetic quartz crucible of 22 inches in diameter was produced by the following procedure. A molded article made of a powder layer having a thickness of 30 mm was formed by supplying a natural silica powder having a diameter of 50 µm or more and 300 µm or less into a rotating mold while performing suction exhaust by the same method as described above. The arc heat amount was raised to 500 kw for 2 minutes by starting heat melting from the inside of the formed body of natural and synthetic silica powder by arc discharge while continuing the suction exhaust. Melting was continued while maintaining the arc calorific value again at 500 kw. In the meantime, the suction exhaust was continuously stopped at the time when 250 torr was increased from the decompression degree at the start of melting. 2 minutes after the start of melting, 1560 g of synthetic silica powder was supplied at 130 g / min for 12 minutes in a high-temperature atmosphere formed inside the molded body, and a total of 0.8 mm thick transparent synthetic quartz glass layer was applied to the inner surface layer of the crucible. To form the first synthetic quartz crucible having a diameter of 22 inches.

The first synthetic quartz crucible was broken, and the side wall, the curved part and the bottom part of the crucible were taken and sliced thinly in parallel to the inner surface direction, and subjected to wet chemical analysis by ICP-MS. As a result, 0.8 from the surface of the inner surface layer of the crucible gas was found. Up to mm was the synthetic quartz glass layer. Again, the sample fragments having a thickness of 3 mm in the cross-sectional direction of the side wall portion, the curved portion, and the bottom portion were made, and the bubbles were observed with an optical microscope, and the bubbles could not be confirmed within 0.8 mm from each surface.

A second synthetic quartz crucible was made in the same manner as the first synthetic quartz crucible. Using the second synthetic quartz glass crucible, the pulling of the silicon single crystal was carried out under reduced pressure. As a result, the vibration of the surface of the silicon melt was so severe that the seeding had to be repeated three times. When the inner surface layer of the crucible after use was observed under an optical microscope, no bubble could be observed within 0.5 mm from the inner surface of the inner surface layer.

Comparative Example 2

Using the same apparatus as in Example 1, a synthetic quartz crucible of 22 inches in diameter was made by the following procedure. While the suction exhaust was performed by the method described above, a natural silica powder having a diameter of 50 µm or more and 300 µm or less was supplied into a rotating mold to form a molded body having a powder layer of 25 mm in thickness. Then, the powder layer of thickness 4mm was formed in the inner surface of the said molded object inside the molded object in the state rotated by the synthetic silica powder of 50 micrometers or more and 300 micrometers or less in diameter. While continuing the suction exhaust, heating was started in the molded body of the natural and synthetic silica powder by arc discharge, and the amount of arc heat was raised to 500 kw for 2 minutes. Melting was continued for another 12 minutes while maintaining the calorific value at 500 kw again. In the meantime, the suction exhaust was stopped at the time when 250 torr was increased from the decompression degree at the time of melting start, and the 1st synthetic quartz crucible of 22 inches in diameter was produced.

The first synthetic quartz crucible was broken, and the side wall, curvature and bottom of the crucible were taken and sliced thinly in parallel to the inner surface direction and subjected to wet chemical analysis by ICP-MS. As a result, the surface of the inner surface layer of the side wall of the crucible gas was found. From 2mm to 2mm was the synthetic quartz glass layer, 6mm from the surface of the inner surface layer at the curved part, and 1.5mm from the surface at the bottom was the synthetic quartz glass layer. Back side wall portion, bend was made in the cross direction of the bottom creating a sample fragments that 3mm thick observe the air bubbles with an optical microscope, a bubble having a diameter of 2μm or more, 140μm or less in less than 1mm from a surface standing on the bottom of the sample 205 / mm ³ It was observed, and the curved side wall portion, within 2mm from the surface of bubbles having a diameter of more than 10μm, 150μm or less were observed 215 / mm ^3, respectively.

A second synthetic quartz crucible was made in the same manner as the first synthetic quartz crucible. When the silicon single crystal was pulled out under reduced pressure with the second synthetic quartz glass crucible, the vibration of the silicon melt surface was weak and the seeding could be carried out smoothly. Crystals scattered in the crystal motion region. Was observed in the surface layer of the crucible after use was observed by an optical microscope within the surface layer within 0.5mm from the inner surface of the air bubble diameter of more than 150μm, 200μm or less is 10 / mm ³ degree it could be seen that while the open.

As described above, the quartz glass crucible for pulling up the silicon single crystal of the present invention has the effect of pulling up the silicon single crystal with high yield without generating dielectric vibration due to vibration of the melt surface and peeling of the quartz glass piece. According to the method of this invention, the effect which can manufacture the quartz glass crucible for silicon single crystal pulling of this invention efficiently can be acquired.

Claims (9)

A silicon single crystal having an opaque quartz glass crucible base outer layer having a bottom portion, a curved portion and a side wall portion, and a quartz glass crucible base formed on the inner surface side of the crucible base outer layer and having an inner layer of a quartz glass crucible gas having a bottom portion, a curved portion and a side wall portion. In an impression quartz glass crucible, a thickness area of not less than 0.5 mm and not more than 4.0 mm from the inner surface of the bottom and sidewall portions of the inner surface of the crucible base and a thickness of not less than 0.5 mm and not more than 10.0 mm from the inner surface of the curved portion of the inner layer of the crucible base. An area is formed of synthetic quartz glass, and in the crucible gas inner layer, a bubble area containing 75 / mm ³ bubbles of 10 μm or more in diameter and 60 μm or less is formed in the side wall part within 2 mm from the inner surface, or the diameter is formed in the side wall part. more than 10μm, to form bubbles of 70μm or less 90 gae / mm ³ containing the bubble region, or at the bottom diameter 10μm Phase, the bubbles of less than 40μm 50 gae / mm ³ to form a containing cell region, or at the bottom diameter of 2μm or more, the air bubbles of less than 40μm 50 gae / mm ³ containing the loop portion and side wall portion in the diameter 10μm or more, 60μm or less A quartz glass crucible for pulling a silicon single crystal, wherein a bubble region containing 75 bubbles / mm ³ is formed. The method of claim 1, wherein a thickness area of 0.5 mm or more and 2 mm or less from an inner surface of the crucible base inner layer to further cover a portion of the crucible base layer further comprises an inorganic cell layer containing no bubbles. 0.5 mm or more and 4.0 mm or less thickness region from the inner surface of the bottom and side wall portions, and 0.5 mm or more and 10.0 mm or less thickness region from the inner surface of the crucible base inner layer and the curved portion of the inorganic cloth region formed of synthetic quartz glass. A quartz glass crucible for raising a silicon single crystal. 3. The quartz glass crucible for pulling a silicon single crystal according to claim 2, wherein the inorganic cloth layer is formed to cover the bottom and the curved portion of the inner layer of the crucible base. 3. The quartz glass crucible for pulling a silicon single crystal according to claim 2, wherein the inorganic cloth layer is formed to cover sidewalls and curved portions of the inner layer of the crucible base. The quartz single crystal pulling silicon according to any one of claims 1 to 4, wherein the diameter of bubbles present in the crucible gas inner layer region within 0.5 mm of the crucible inner surface after silicon single crystal pulling is not more than 150 µm. Glass crucible. Filling the natural silica powder along the inner circumferential surface of the rotating gas permeable mold; Again filling the synthetic silica powder so as to cover part or all of the inner surface of the natural silica powder compact; Meanwhile heating and melting the packed layer of natural and synthetic silica powder with an arc flame from the inner surface side while performing suction exhaust through the wall of the mold; And forming a crucible gas consisting of an opaque quartz glass crucible base outer layer and a quartz glass crucible inner layer while performing suction exhaust through the wall of the mold therebetween; 0.5 mm or more and 4.0 mm or less thickness regions from the inner surfaces of the bottom and sidewall portions of the crucible inner layer and 0.5 mm or more and 10.0 mm or less thickness regions from the inner surface of the curved portion of the crucible body inner layer are formed of synthetic quartz glass, In the inner surface of the crucible body, a bubble region containing 75 / mm ³ of bubbles having a diameter of 10 μm or more and 60 μm or less is formed in the side wall portion within 2 mm from the inner surface, or a bubble having a diameter of 10 μm or more and 70 μm or less is formed in the side wall portion. Forming a bubble area containing openings / mm ³ , or forming a bubble area containing 50 bubbles / mm ³ at the bottom of 10 μm or more in diameter and 40 μm or less, or forming a bubble space containing at least 2 μm in diameter and 40 μm or less at the bottom. dog / mm ³ containing the loop portion and side wall portion in the diameter 10μm or more, also of quartz glass for the silicon single crystal pulling, characterized in that the formation of the bubble domain containing bubbles of 60μm or less 75 pieces / mm ³ Manufacturing method. Filling the natural silica powder along the inner circumferential surface of the rotating gas permeable mold; Again, the synthetic silica powder is filled so as to cover part or all of the inner surface of the natural silica powder compact; In the meantime, while performing a suction exhaust through the wall of the said mold, heat-melting the packed layer of the said natural and synthetic silica powder with an arc flame from the inner surface side; A gas formation step of forming a crucible gas comprising an opaque quartz glass crucible base outer layer and a quartz glass crucible inner layer while performing suction exhaust through the wall of the mold; Simultaneously with or after the formation of the crucible gas, a synthetic silica powder is supplied to the inside of the crucible gas in a hot gas atmosphere formed by the arc flame and adhered to and melted on the inner surface of the crucible gas inner layer. An inorganic cloth layer forming step of forming an inorganic cloth layer containing substantially no bubbles, wherein the thickness area of 0.5 mm or more and 4.0 mm or less from the inner surface of the crucible base inner layer and the bottom and sidewall portions of the inorganic cloth layer and the crucible base A thickness region of 0.5 mm or more and 10.0 mm or less from the inner surface of the curved portion of the inner layer and the inorganic cloth layer is formed of synthetic quartz glass, and the sidewall portion of 2 mm or less from the inner surface of the crucible base layer has a diameter of 10 µm or more and 60 µm or less. bubbles 75 / mm ³ to form a cell-containing region, or from the side wall part diameter than 10μm, 70μm or less Forming a cell region containing the bubble ³⁹⁰ / mm, or even at the bottom diameter of 10μm or more, the air bubbles of less than 40μm 50 lines / mm ³ to form a containing cell region, or at the bottom diameter of 2μm or more, less than 40μm bubbles 50 / mm ^3, and containing curved portion and side wall portion in the diameter of 10μm or more, to form a cell region containing the bubbles of 60μm or less 75 gae / mm ^3, and the inorganic fabric layer is of at least 0.5mm, 2mm or less from the inner surface A method of manufacturing a quartz glass crucible for pulling a silicon single crystal, wherein the thickness region is free of bubbles. The method of claim 7, wherein the inorganic cloth layer is formed to cover the bottom and the curved portion of the inner layer of the crucible base.  The method of claim 7, wherein the inorganic cloth layer is formed to cover sidewalls and curved portions of the inner layer of the crucible base.

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