JP2001302391A - Method for producing quartz glass crucible for pulling Si single crystal - Google Patents

Abstract

(57) [Summary] [Problem] S that is hard to soften at high temperature, has high viscosity and has little deformation
Provided is a method for manufacturing a quartz glass crucible for pulling a Si single crystal, which can obtain a quartz glass crucible for pulling an i single crystal. SOLUTION: A bottomed cylindrical shape having an inner surface following the outer surface of a crucible is provided in a bottomed cylindrical holder 2, and
Using a mold 5 in which a gas permeable inner member 3 is inserted with a ventilation space 4 between the inner surface of the holding member and the inner surface of the holder, quartz is formed in the inner member while rotating the mold around the axis. After supplying the powder and forming a quartz powder deposited layer 7 having a required thickness following the inner surface thereof, it is heated from the inside to produce a quartz glass crucible for pulling a Si single crystal which is transparent on the inside and opaque on the outside. In the method, at the same time as the heating of the quartz powder deposition layer is started, the quartz powder deposition layer is sucked through the ventilation space to depressurize the quartz powder deposition layer for a required time, and then the argon gas is supplied to the quartz powder deposition layer through the ventilation space.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to Si (silicon).
The present invention relates to a method for manufacturing a quartz glass crucible used when a single crystal is pulled by a CZ (Czochralski) method.

[0002]

2. Description of the Related Art Conventionally, as a method for producing this type of quartz glass crucible for pulling a Si single crystal, as shown in FIG.
In a holder 32 having a bottomed cylindrical shape and having a vent hole 31 at the bottom center, a bottomed cylindrical shape having an inner surface following the outer surface of a crucible (not shown), and gas A mold 35 was used in which a permeable inner member 33 was inserted with a ventilation space 34 provided between the inside member 33 and the inner surface of the holder 32, and the mold 35 was vertically provided at the center of the bottom of the holder 32. Quartz powder is supplied into the inner member 33 by a supply pipe (not shown) while being rotated about the axis in the direction of the arrow P shown in the drawing by a rotary driving device (not shown) via the hollow rotary shaft 36, and the inner member 3
After a quartz powder deposition layer 37 having a required thickness is formed following the inner surface of the inner electrode 3, heating is started by an arc using the arc electrodes 38 and 39, and the ventilation space 34 is passed through a vacuum pump (not shown). A method is known in which the quartz powder deposition layer 37 is depressurized by sucking in the direction indicated by arrow Q through the hollow portion of the pores 31 and the rotating shaft 36 to form a quartz glass crucible with a transparent inside and an opaque outside (Japanese Patent Publication No. Hei 9-222). 5-85515). In FIG. 3, reference numeral 40 denotes a pedestal, which is connected to a fixed base (both not shown) via a bearing.

[0003]

However, in the conventional method for manufacturing a quartz glass crucible for pulling a Si single crystal,
Low viscosity, especially the outer opaque quartz glass layer,
There is a problem that the crucible is easily deformed at a high temperature. This is because the quartz powder deposition layer 37 is heated in the air and the pressure reduction operation of the quartz powder deposition layer 37 is performed from the outside through the ventilation space 34 from the start of the operation. Melting takes place from the inside of the deposition layer 37 and the nitrogen in the air taken into the crucible reacts with the quartz particles to form low-viscosity glass. In addition, carbon crucible used when the crucible is used. It reduces the quartz by reacting with to generate silicon monoxide.

Accordingly, the present invention provides a method for producing a quartz glass crucible for pulling a Si single crystal, which is hardly softened at a high temperature, is highly viscous, and can be obtained with a small deformation. Aim.

[0005]

In order to solve the above-mentioned problems, a first method for producing a quartz glass crucible for pulling a Si single crystal according to the present invention is provided in a cylindrical holding body having a bottom, following the outer surface of the crucible. Presents a cylindrical shape with a bottom having an inner surface, and
Using a mold having a gas-permeable inner member inserted with a ventilation space between the inner surface of the holder and the inner surface of the holder, quartz powder is supplied into the inner member while rotating the mold around the axis. , After forming a quartz powder deposition layer of the required thickness following the inner surface,
In a method for manufacturing a quartz glass crucible for pulling a Si single crystal that is transparent on the inside and opaque on the outside by heating the quartz powder deposition layer from the inside, the heating is started through the quartz powder deposition layer, and the quartz powder crucible is sucked through the ventilation space. After depressurizing the quartz powder deposited layer for a required time, argon gas is supplied to the quartz powder deposited layer through the ventilation space.

Further, a second method for producing a quartz glass crucible for pulling a Si single crystal has a bottomed cylindrical shape having an inner surface following the outer surface of the crucible in a bottomed cylindrical holder, and Using a mold having a gas-permeable inner member inserted with a ventilation space between the inner surface of the holder and the inner surface of the holder, quartz powder is supplied into the inner member while rotating the mold around the axis. ,
After forming a quartz powder deposited layer of a required thickness following the inner surface, the quartz powder deposited layer is heated from the inside to produce a quartz glass crucible for pulling a Si single crystal that is transparent on the inside and opaque on the outside, Supplying hydrogen gas and / or helium gas from the inside of the inner member to the quartz powder deposition layer for a required time together with the heating of the quartz powder deposition layer, and then supplying argon gas to the quartz powder deposition layer through the ventilation space. It is characterized by.

A third method of manufacturing a quartz glass crucible for pulling a Si single crystal is to provide a bottomed cylindrical shape having an inner surface following the outer surface of the crucible in a bottomed cylindrical holder, and Using a mold having a gas-permeable inner member inserted with a ventilation space between the inner surface of the holder and the inner surface of the holder, quartz powder is supplied into the inner member while rotating the mold around the axis. ,
After forming a quartz powder deposited layer of a required thickness following the inner surface, the quartz powder deposited layer is heated from the inside to produce a quartz glass crucible for pulling a Si single crystal that is transparent on the inside and opaque on the outside, Hydrogen gas and / or helium gas are supplied to the quartz powder deposition layer through the ventilation space for a required time together with the start of heating of the quartz powder deposition layer, and then argon gas is supplied to the quartz powder deposition layer through the ventilation space. I do.

In the first method for manufacturing a quartz glass crucible for pulling a Si single crystal, the inside of a quartz powder deposition layer is made into a transparent quartz glass layer in a reduced-pressure atmosphere containing little nitrogen and oxygen, and the outside is made inert. An opaque quartz glass layer is formed in an argon gas atmosphere.

The pressure reduction is preferably performed at a pressure of 0.01 to 0.4 kgf / cm ² , more preferably 0.01 to 0.4 kgf / cm ^2.
0.2 kgf / cm ² . Decompression pressure is 0.01kgf / cm ²
If it is less than this, the amount of SiO ₂ (silicon dioxide) gas increases, and a crucible having a predetermined weight cannot be obtained. Also, 0.4
If it is 0.5 kgf / cm ² exceeding kgf / cm ² , air mixed from the atmosphere causes bubbles, a completely transparent layer cannot be formed inside, and if it exceeds 0.6 kgf / cm ² , More bubbles and opacity in appearance. On the other hand, the decompression holding time is
It is preferably 3 to 10 minutes, more preferably 4 to 5 minutes. If the reduced pressure holding time is less than 3 minutes, the thickness of the transparent layer becomes as thin as about 2 mm, and the boundary between the transparent layer and the outer opaque layer becomes unclear. Also, if it exceeds 10 minutes,
While the thickness of the transparent layer is 5 mm or more, the portion where the opaque layer is formed is reduced accordingly. The supply amount of argon gas is 10
To 100 l / min, more preferably 30 to 50 l / min.
l / min. If the supply amount of the argon gas is less than 10 l / min, air mixed from the atmosphere remains, and bubbles containing nitrogen gas (N ₂ ) are formed. On the other hand, if it exceeds 100 l / min, bubbles due to argon gas increase and the density decreases. The supply of the argon gas is continued until the superheating operation ends.

In the second and third methods for producing a quartz glass crucible for pulling a Si single crystal, the quartz powder deposited layer is formed into a transparent quartz glass layer in a hydrogen gas and / or helium gas atmosphere. The opaque quartz glass layer is formed in an inert atmosphere of argon gas.

[0011] The hydrogen gas and / or helium gas supply and retention time is preferably 2 to 10 minutes, more preferably 4 minutes.
~ 5 minutes. If the supply holding time is less than 2 minutes, the thickness of the transparent layer becomes as thin as about 2 mm, and the boundary between the transparent layer and the opaque layer becomes unclear. If the time exceeds 10 minutes, the thickness of the transparent layer becomes 5 mm or more, but the portion where the opaque layer is formed is reduced accordingly. The supply amount of hydrogen gas and / or helium gas is preferably 5 to 30 l / min, more preferably 10 to 20 l / min. If the supply amount of the hydrogen gas and / or the helium gas is less than 5 l / min, air mixed from the atmosphere causes bubbles, and a complete transparent layer cannot be formed. Also, if it exceeds 30 l / min, hydrogen and / or helium do not completely dissolve in the glass,
Hydrogen and / or helium gas is left as it is, bubbles are increased, and a completely transparent layer cannot be formed. The supply rate of the argon gas is preferably from 10 to 100 l / min, more preferably from 30 to 50 l / min. The supply amount of argon gas is
If it is less than 10 l / min, air mixed in from the atmosphere remains, and bubbles containing nitrogen gas are formed. Also, 100l / min
If it exceeds, bubbles due to argon gas increase and the density decreases. The supply of the argon gas is continued until the heating operation ends.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to specific examples. Example 1 First, as shown in FIG. 1, a vertical holder 2 having a bottomed cylindrical shape and having a vent hole 1 provided at the center of the bottom.
Inside, a gas having a cylindrical shape with a bottom having an inner surface following the outer surface of a crucible (not shown) and having a large number of through-holes, or made of a highly purified porous carbon or the like. Inner member 3 (580 mm inside diameter, 400 m height)
m) is performed by using a molding die 5 inserted and fitted with an air space 4 between the inner surface of the holding body 2 and this molding die 5 suspended vertically at the center of the bottom of the holding body 2. Two supply pipes (not shown) for the peripheral surface and the bottom surface are introduced into the inner member 3 while rotating (80 rpm) around the vertical axis in the direction of the arrow A shown in the figure by a rotary driving device (not shown) via the shaft 6. ) Is supplied via the inner surface of the inner member 3 to a required thickness (1).
(5 mm) quartz powder deposited layer 7 was formed.

Next, heating from the inside of the quartz powder deposition layer 7 is started by an arc using the arc electrodes 8 and 9, and the ventilation space 4, the ventilation hole 1, and the rotating shaft are rotated by a vacuum pump (not shown). 0.19kgf / through the hollow part in the direction of arrow B
After the quartz powder deposition layer 7 was depressurized by suction for 4.5 minutes at a pressure of ² cm ² , argon gas was supplied from a gas supply source (not shown) to the hollow portion of the rotating shaft 6, the ventilation hole 1 and the ventilation space 4. The feed rate is 40 l / min in the direction of arrow C in the drawing, and the quartz powder is supplied to the quartz powder deposition layer 7 until the heating operation is completed. Obtained a quartz glass crucible for pulling a Si single crystal having an opaque quartz glass layer. In FIG. 1, reference numeral 10 denotes a pedestal, which is connected to a fixed seat (both not shown) via a bearing.

Example 2 First, using the same manufacturing apparatus as in Example 1, and rotating the molded product in the same manner as in Example 1, high-purity quartz powder was supplied to the inner member through two supply pipes. The silica powder was supplied into the inside and a quartz powder deposited layer having a required thickness (15 mm) was formed following the inner surface thereof. Next, while heating from the inside of the quartz powder deposition layer with an arc using an arc electrode,
After supplying hydrogen gas and / or helium gas from a gas supply source (not shown) at a supply rate of 10 l / min for 10 minutes to the quartz powder deposition layer through the hollow portion of the rotating shaft, the ventilation hole and the ventilation space, Similarly, argon gas was supplied to the quartz powder deposition layer at a supply rate of 40 l / min until the heating operation was completed, through the hollow portion of the rotating shaft, the vent hole, and the vent space, and the outer diameter was 560 mm, the height was 400 mm, and the wall thickness was 400 mm. A quartz glass crucible having a thickness of 12 mm and having a transparent quartz glass layer on the inside and an opaque quartz glass on the outside was used for pulling a Si single crystal.

The quartz powder deposited layer is sequentially melted from the inside by heating, and the microbubbles of hydrogen gas and / or helium gas contained in the fused quartz powder deposited layer are reduced to hydrogen gas and / or helium gas. Since the atomic radius of the helium gas is small, the helium gas is released from the inside of the fused quartz powder deposition layer as it moves and is released by internal diffusion. In addition, it is considered that bubbles of hydrogen gas and / or helium gas are absorbed by the quartz powder structure and disappear, so that only small bubbles are formed inside, thereby achieving substantially bubble-free transparency. Can be

As shown in FIG. 2, the characteristics of the quartz glass crucibles according to Examples 1 and 2 and the characteristics of a conventional quartz glass crucible obtained by using the same manufacturing apparatus as in Example 1 were examined. T ₁ , T ₂ ,
Samples of a given dimension of the transparent quartz glass layer and the opaque vitreous silica layer from three of T ₃ was cut out, respectively. Then, in order to examine the viscosity, softening point of each sample cut from the T ₁ position was measured the temperature of annealing point and strain point were as shown in table 1.

[0017]

[Table 1]

As can be seen from Table 1, the quartz glass crucibles obtained in Examples 1 and 2 have the same viscosities of the transparent quartz glass layer as those of the conventional method, but have the same opaque quartz glass layer. Is increased by 10 to 20 ° C.

Further, in order to examine the rate of change in bulk density of the opaque quartz glass layer, each sample was kept at 1600 ° C. for 3 hours in an argon gas atmosphere at a pressure of 10 Torr, and the rate of change in bulk density at room temperature was compared. The results are as shown in Table 2.

[0020]

[Table 2]

As can be seen from Table 2, the opaque quartz glass layers of the quartz glass crucibles obtained in Examples 1 and 2 are:
The rate of change in bulk density is smaller than that by the conventional method, indicating that the volume expansion due to expansion of the bubbles is small.

After the quartz powder deposition layer is started to be heated, hydrogen gas and / or helium gas is supplied to the quartz powder deposition layer from the inside of the inner member for a required time, and then argon gas is heated to the quartz powder deposition layer through the ventilation space. In the case where the quartz glass crucible for pulling the Si single crystal was supplied until the operation was completed to obtain a quartz glass crucible, almost the same as those in Examples 1 and 2 was obtained.

[0023]

As described above, according to the first embodiment of the present invention,
According to the method for manufacturing a quartz glass crucible for pulling a single crystal, the inside of the quartz powder deposition layer is made into a transparent quartz glass layer in a reduced-pressure atmosphere with little nitrogen and oxygen, and then the outside is made opaque in an inert argon gas atmosphere. As a result, the opaque quartz glass layer can be made highly viscous and the bubbles contained therein can be made to have low expansion as compared with the conventional manufacturing method. Further, according to the second and third methods for manufacturing a quartz glass crucible for pulling a Si single crystal, the inside of the quartz powder deposition layer is formed into a transparent quartz glass layer in a hydrogen gas and / or helium gas atmosphere, and then the outside is formed. Is an opaque quartz glass layer in an inert argon gas atmosphere, so that the opaque quartz glass layer is made more viscous and the bubbles contained therein are less expanded than the first method, compared to the conventional manufacturing method. Can be achieved.

Therefore, according to the quartz glass crucible for pulling a Si single crystal obtained by the first, second, and third manufacturing methods, the shape change of the quartz glass crucible during the pulling of the Si single crystal can be controlled by the conventional manufacturing method. Stabilizes the shape to a lesser extent than by the method, which results in a longer life due to the change and a longer use. In addition, the increase in volume of the quartz glass crucible due to the expansion of bubbles is suppressed, and as a result, the liquid level of the Si melt hardly changes during the pulling of the Si single crystal, thereby improving the yield of the Si single crystal. Can be done.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a manufacturing apparatus provided for carrying out an embodiment of a method for manufacturing a quartz glass crucible for pulling a Si single crystal according to the present invention.

FIG. 2 is a cross-sectional view showing a sampling position of a sample from a quartz glass crucible obtained by the method for producing a quartz glass crucible for pulling a Si single crystal according to the present invention.

FIG. 3 is a cross-sectional view of a manufacturing apparatus provided for carrying out a conventional method for manufacturing a quartz glass crucible for pulling a Si single crystal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 2 Holder 3 Inner member 4 Ventilation space 5 Mold 6 Rotation axis 7 Quartz powder deposition layer 8 Arc electrode 9 Arc electrode

Claims (3)

[Claims] 1. A bottomed cylindrical holding body having a bottomed cylindrical shape having an inner surface following the outer surface of a crucible, and a gas-permeable inner member provided between the holding member and the inner surface of the holding body. Using a mold inserted and fitted with a ventilation space, quartz powder is supplied into the inner member while rotating the mold around the axis, and a quartz powder deposition layer of the required thickness is formed following the inner surface After that, in the method for manufacturing a quartz glass crucible for pulling a Si single crystal which is transparent on the inside and opaque on the outside by heating the quartz powder deposition layer from the inside, the heating of the quartz powder deposition layer and the passing of the air through the ventilation space are performed. A method for producing a quartz glass crucible for pulling up a Si single crystal, comprising suctioning and depressurizing a quartz powder deposition layer for a required time, and then supplying argon gas to the quartz powder deposition layer through a ventilation space. 2. A bottomed cylindrical body having a bottomed cylindrical shape having an inner surface following the outer surface of a crucible, and a gas-permeable inner member being interposed between the bottomed cylindrical body and the inner surface of the holder. Using a mold inserted and fitted with a ventilation space, quartz powder is supplied into the inner member while rotating the mold around the axis, and a quartz powder deposition layer of the required thickness is formed following the inner surface And then heating the quartz powder deposited layer from the inside to produce a quartz glass crucible for pulling up the Si single crystal, the inside of which is transparent and the outside is opaque. A hydrogen gas and / or a helium gas are supplied to the quartz powder deposition layer for a required time, and then an argon gas is supplied to the quartz powder deposition layer through the ventilation space, thereby producing a quartz glass crucible for pulling a Si single crystal. . 3. A bottomed cylindrical body having a bottomed cylindrical shape having an inner surface following the outer surface of a crucible, and a gas-permeable inner member provided between the bottomed cylindrical holder and the inner surface of the holder. Using a mold inserted and fitted with a ventilation space, quartz powder is supplied into the inner member while rotating the mold around the axis, and a quartz powder deposition layer of the required thickness is formed following the inner surface Then, in the method for heating the quartz powder deposited layer from the inside to produce a quartz glass crucible for pulling up the Si single crystal whose inside is transparent and whose outside is opaque, the quartz is passed through the ventilation space together with the start of heating of the quartz powder deposited layer. A method for producing a quartz glass crucible for pulling a Si single crystal, comprising supplying hydrogen gas and / or helium gas to a powder deposition layer for a required time, and then supplying argon gas to the quartz powder deposition layer through a ventilation space.