JP4493067B2 - Quartz glass crucible manufacturing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a quartz glass crucible manufacturing apparatus used in, for example, a semiconductor device manufacturing process.
[0002]
[Prior art]
A substrate of a semiconductor device is generally formed of a silicon single crystal generated using a Czochralski method.
Such a Czochralski method involves melting a polycrystalline silicon raw material in a quartz glass crucible, then bringing it into contact with a solid seed crystal and then growing a single crystal under the seed crystal while gradually pulling it up. To be implemented.
For this reason, a quartz glass crucible manufacturing apparatus used for manufacturing a substrate for a semiconductor device is required to have a crucible molding die having durability (heat resistance).
[0003]
Conventionally, this type of quartz glass crucible manufacturing apparatus is disclosed, for example, in Japanese Patent Application Laid-Open No. 2000-72458 as “quartz glass crucible manufacturing apparatus” and is configured as shown in FIG.
This includes a crucible molding die (rotating body) 71 having a space portion 71 a for forming a quartz glass crucible and a through hole 71 b opening inside and outside the space portion 71 a, and a space portion 71 a of the crucible molding die 71. Heating means 72 for melting the quartz glass raw material powder M supplied therein. Further, an intake means 73 having an intake pipe 73a for sucking the inside of the crucible molding mold 71 from the through hole 71b and a communication pipe 73a communicating with the intake pipe 73a when heated by the heating means 72 (at the time of crucible molding), And a cooling means 74 for cooling the crucible forming mold 71.
[0004]
In the production of the quartz glass crucible using such an apparatus, first, the quartz glass raw material powder M is supplied into the crucible forming mold 71 rotated at a high speed. Next, the inside of the crucible forming mold 71 is sucked by the suction means 73, and the layered quartz glass raw material powder M in the crucible forming mold 71 is heated and melted by the heating means 72 almost simultaneously with the suction processing. At this time, the crucible forming mold 71 is cooled by the cooling means 74.
[0005]
[Problems to be solved by the invention]
By the way, in this type of quartz glass crucible manufacturing apparatus, the crucible forming mold 71 is rotated at a high speed during molding and the inside of the crucible forming mold 71 is sucked, so that the communication pipe 73b of the intake means 73 is crucible molded. A structure that is arranged on the axis of the mold 71, that is, a structure that is attached to the bottom center of the crucible forming mold 71 is employed.
For this reason, when cooling the crucible molding die 71, the central portion of the bottom surface cannot be sufficiently cooled, and this portion is oxidized during crucible molding (heating), and the molded product (quartz glass crucible) is contaminated by the oxide. There was a problem that it was easy to end up.
[0006]
Further, in such a quartz glass crucible manufacturing apparatus, since no through hole is provided in the center of the bottom surface of the crucible molding die 71, the suction (decompression) force is lower in the center of the bottom surface in the mold than in the outer periphery. However, the transparent layer of the molded product becomes thin at the center of the bottom surface, and the bubble distribution of the opaque layer becomes non-uniform, which makes it difficult to obtain a molded product having uniform characteristics.
Furthermore, the fact that a sufficient decompression force is not secured at the bottom center portion of the crucible molding die 71 means that the bottom center portion a of the molded product A rises as shown in FIG. Alternatively, when a round bottom molded product is manufactured, there is a problem that it is difficult to obtain a molded product having a desired shape by forming a molded product B having a flat bottom b as shown in FIG.
[0007]
The present invention has been made to solve such a technical problem, and can prevent the molded product from being contaminated, and can also provide a molded product having uniform characteristics and a desired shape. An object is to provide a quartz glass crucible manufacturing apparatus.
[0008]
[Means for Solving the Problems]
A quartz glass crucible manufacturing apparatus according to the present invention made to achieve the above-mentioned object is a bottomed cylindrical body for forming a quartz glass crucible by supplying quartz glass raw material powder for crucible molding, A crucible molding die having a first through hole that opens at the outer peripheral portion of the bottomed cylindrical body and a second through hole that opens at the center of the bottom surface, with the central axis as the rotation axis, and outside the crucible molding die An intake means having a first ventilation duct that communicates with the first through-hole and a second ventilation duct that communicates with the second through-hole, and an outside of the ventilation duct of the intake means, the crucible molding A cooling means for cooling the mold, and through this cooling means, the first cooling portion that covers the outer periphery of the first ventilation duct and the crucible molding die, and the second ventilation duct are inserted, And covering the center of the bottom of the crucible mold Characterized in that included a second cooling unit UNA.
[0009]
Since it comprises in this way, the outer peripheral part of the crucible shaping | molding die is cooled by the 1st cooling part, and the bottom center part of the crucible shaping | molding die is cooled by the 2nd cooling part.
Accordingly, not only the outer peripheral portion of the crucible molding die but also the central portion of the bottom surface is sufficiently cooled, so that these portions are difficult to oxidize during crucible molding (heating), thereby preventing the occurrence of contamination of the molded product by the oxide. be able to.
In addition, the first through hole is provided in the outer peripheral portion of the crucible molding die, and the second through hole is provided in the central portion of the bottom surface, so that intake (decompression) force is generated at the outer peripheral portion and the bottom central portion of the crucible molding die. Is sufficiently ensured, the thickness of the transparent layer of the molded product and the bubble distribution of the opaque layer are uniform, and a molded product having uniform characteristics can be obtained.
In addition, since sufficient decompression force is secured at the outer periphery and bottom center of the crucible molding die, the bottom center of the molded product rises as the molded product becomes larger, or a round bottom molded product is produced. In this case, a molded product having a desired shape can be obtained without forming a molded product having a flat bottom.
[0010]
Here, it is preferable that both the cooling parts are formed of cylindrical parts located concentrically with a rotation axis of the crucible forming mold as a central axis.
Due to such a configuration, it is possible to reduce the occurrence of variation in characteristics in the circumferential direction of the quartz glass crucible.
Moreover, it is desirable that the inner diameter of the second cooling part is set to a size that is 15 to 50% of the inner diameter of the crucible molding die.
Since it is comprised in this way, the bottom center part of the said mold for crucible shaping | molding can be cooled more correctly, and the above-mentioned effect can be made more reliable.
[0011]
Here, it is desirable to provide the first ventilation duct with a bulging portion having a space for allowing the second cooling portion to face.
Since it is comprised in this way, a 2nd cooling part is arrange | positioned in the bulging part of a 1st ventilation duct.
[0012]
In addition, the through hole is formed by a stepped hole having a plurality of hole portions having different diameters and a filter mounting surface interposed between two adjacent hole portions among the hole portions. Further, it is preferable that a mounting screw for press-contacting the air-permeable filter is screwed onto the filter mounting surface.
Since it is configured in this manner, the entire breathable filter can be accommodated in the through hole of the crucible molding die when the filter is attached.
Therefore, since a breathable filter or the like is not disposed in the ventilation duct, the ventilation resistance in the ventilation duct is reduced.
As a result, the driving power during the intake air treatment can be reduced, the intake time can be shortened, and the productivity can be increased.
[0013]
Further, the attachment of the air permeable filter to the crucible molding die is performed by pressing the filter end surface against the filter mounting surface of the through hole in the crucible molding die and screwing the mounting screw into the through hole. Insertion of the breathable filter into the mounting screw, which was conventionally required when the filter was mounted, is unnecessary, and the filter mounting operation can be simplified.
Further, the fact that the air permeable filter or the like is not disposed in the air duct increases the internal volume of the air duct, and the exhaust efficiency at the time of intake processing can be reliably increased.
[0014]
And it is desirable that the diameter of the space side hole in the hole is set to be larger than the diameter of the duct side hole.
Since it is configured in this manner, the breathable filter can be attached and detached from the crucible molding die during filter replacement, and the filter replacement operation can be performed quickly.
[0015]
Further, it is desirable that the mounting screw is formed by a disk-shaped filter mounting member having a screw portion screwed into the inner peripheral surface of the through hole and a flat hexagonal exhaust hole opened in the axial direction. .
Since it is comprised in this way, since the exhaust hole of the screw for attachment can be utilized as a tool insertion port at the time of filter attachment / detachment, the workability | operativity can be improved.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a quartz glass crucible manufacturing apparatus according to the present invention will be described based on the embodiments shown in the drawings. FIG. 1 is a cross-sectional view showing the entire quartz glass crucible manufacturing apparatus to which the present invention is applied. 2 is an enlarged cross-sectional view showing the main part of FIG. 1, and FIG. 3 is a cross-sectional view taken along line AA of FIG. FIG. 4 is a perspective view showing a crucible molding die of a quartz glass crucible manufacturing apparatus to which the present invention is applied. 5A and 5B are perspective views showing a mounting screw and a breathable filter of a quartz glass crucible manufacturing apparatus to which the present invention is applied. As shown in FIG. 1, a quartz glass crucible manufacturing apparatus denoted by reference numeral 1 includes a crucible forming mold 2 for forming a quartz glass crucible, and a quartz glass raw material powder M supplied into the crucible forming mold 2. And heating means 3 for heating and melting. Furthermore, a driving means 4 for rotating the crucible molding die 2 at a high speed, an intake (decompression) means 5 for taking in air from the crucible molding die 2 when heated by the heating means 3 (at the time of crucible molding), And a cooling means 6 for cooling the crucible molding die 2.
[0017]
The crucible molding die 2 is composed of a substantially inverted bell-shaped container (a bottomed cylindrical body having a diameter of about 18 to 36 inches) having a space 2a to which the quartz glass raw material powder M is supplied, and the whole is a metal such as stainless steel. (Heat resistant member). On the cylindrical wall of the crucible molding die 2, for example, four rows of first rows are formed in parallel with each other along the contour from the opening edge to the bottom as shown in FIG. 4. A through hole 2b is provided. In addition, a plurality of (for example, four) second through holes 2c are provided at the center of the bottom surface of the crucible molding die 2 and open to the inside and outside of the space 2a.
[0018]
The through holes 2b and 2c are, as shown in FIG. 3, three large, medium and small hole portions 2A to 2C having different diameters and between the two hole portions 2A and 2B and between the two hole portions 2B and 2C. It is formed by a stepped hole having 2D and 2E (in this embodiment, the function as a filter mounting surface is only 2E). Of these, the large-diameter hole 2A is a screw hole, and communicates with the space 2a of the crucible molding die 2. The hole 2B having an intermediate diameter is a through hole and communicates with both the holes 2A and 2C. The small-diameter hole portion 2C is a through-hole as in the case of the hole portion 2B, and communicates with the exhaust passage (both described later) of the first ventilation duct. The filter mounting surfaces 2D and 2E are formed by a plane perpendicular to the axis of the holes 2A to 2C.
The number of the through holes 2b and 2c can be appropriately adjusted according to the size of the quartz glass crucible.
[0019]
And in the said through-holes 2b and 2c (hole part 2B), the screw 7 for attachment shown to Fig.5 (a) is used, and the peripheral part of the air permeable filter 8 shown to the same figure (b) is set to the said filter attachment surface. The breathable filter 8 is fixed in pressure contact with 2E. This eliminates the need to dispose the air-permeable filter 8 in the exhaust passages of the first ventilation duct and the second ventilation duct, which will be described later, thereby reducing the ventilation resistance in the exhaust passage 10 and reducing the driving power during intake processing. In addition, the intake time can be shortened and productivity can be increased. Further, the work for inserting the air-permeable filter 8 into the clasp, which was conventionally required when the filter was attached, becomes unnecessary, and the filter attachment work can be simplified. Furthermore, the fact that the air permeable filter 8 is not disposed in the exhaust path of the ventilation duct increases the volume of the exhaust path and can improve the exhaust efficiency during the intake process.
[0020]
The mounting screw 7 is a disk-shaped mounting screw having a threaded portion 7a on the outer peripheral surface, and is screwed into the hole portions 2A of the through holes 2b and 2c. The mounting screw 7 is provided with a plane hexagonal exhaust hole 7b that opens in the axial direction. Thereby, the opening part of the exhaust hole 7b in the screw 7 for attachment can be utilized as a tool insertion port at the time of filter attachment / detachment, and the workability | operativity can be improved. Further, one side opening of the exhaust hole 7b is communicated with the space 2a, and the other side opening is communicated with the air permeable filter 8 in the hole 2C.
[0021]
The air permeable filter 8 is formed of a disk-like air permeable filter made entirely of a heat resistant porous material such as quartz or silicon carbide (SiC). This exhibits air permeability with respect to an intake gas such as air, argon gas or nitrogen gas, but does not allow the quartz glass raw material powder M to pass therethrough. The outer diameter of the breathable filter 8 is set to a size smaller than the diameter of the holes 2A and 2B (because the breathable filter 8 is accommodated in the holes 2A and 2B), and the outer diameter of the hole 2C. The size is set larger than the aperture. Thereby, the breathable filter 8 can be attached and detached from the crucible molding die 2 at the time of filter replacement, and the filter replacement operation can be performed quickly. The filter thickness is set to be slightly larger than the depth of the hole 2B (because the air permeable filter 8 receives the tightening force by the mounting screw 7).
[0022]
The heating means 3 is made of, for example, an arc electrode, and is disposed in the vicinity of the crucible molding die 2 with its tip portion facing the space portion 2a. The quartz glass raw material powder M supplied into the crucible molding die 2 can be heated and melted.
The drive means 4 is composed of a drive motor, and is connected to the central part of the bottom surface of the crucible molding die 2 (duct junction part described later) via a motor shaft 4a. The crucible molding die 2 is configured to rotate at high speed around the central axis during crucible molding. A space 4A is formed in the motor shaft 4a to accommodate a third ventilation duct (rotating duct), which will be described later.
[0023]
The intake means 5 is disposed outside the crucible molding die 1. The intake means 5 includes a first ventilation duct 5a having a U-shaped cross section for forming an exhaust passage 10 communicating with both the through holes 2b, and the exhaust passage 10 and the through hole 2c of the first ventilation duct 5a. It has a tubular second ventilation duct 5b for forming a communicating exhaust passage 10a. Also, a tubular third ventilation duct 5c for connecting to the first ventilation duct 5a to form a common flow path 11 communicating with the exhaust passages 10, 10a, and the third ventilation duct 5c connected to the third ventilation duct 5c. It has a suction pump 5d for sucking the intake gas in the crucible molding die 2.
[0024]
The first ventilation duct 5a is composed of four ducts covering the outer opening of the first through hole 2b, and is disposed on the exhaust side of the breathable filter 8 as shown in FIG. It is fixed to the outer periphery of the mold 2. As shown in FIG. 4, the first ventilation duct 5a includes a straight duct portion 5A extending along the axial direction of the crucible molding die 2, and a bottom surface of the crucible molding die 2 from the straight duct portion 5A. And a curved duct portion 5B extending toward the portion. Further, a duct junction 5C as a bulging portion that forms an internal space in the vicinity of the center of the bottom surface of the crucible molding die 2 is provided below the first ventilation duct 5a (exhaust passage 10). ing.
[0025]
The second ventilation duct 5b is composed of four ducts communicating with the second through hole 2c and the duct junction 5c, is attached to the opening peripheral edge of the second through hole 2c, and is a second cooling section described later. Is inserted.
The third ventilation duct 5c includes a rotating duct portion 5D extending in the vertical direction in the space portion 4A and rotating together with the motor shaft 4a, and a coupling fixing portion (both described later) in the rotating duct portion 5D. It is formed by a single duct having a fixed duct portion 5E that is coupled together.
[0026]
The suction pump 5d is connected to the third ventilation duct 5c. Then, the pump side is the suction (decompression) side, the inside of the crucible molding mold 2 is the suction target side, and the suction side in the crucible molding mold 2 is passed through the air-permeable filter 8 during crucible molding (intake processing). It is configured such that gas (air when the inside of the crucible molding die 2 is an air atmosphere) can be sucked.
[0027]
The cooling means 6 includes a first cooling section 6a that covers the outer periphery of the first ventilation duct 5a and the crucible molding mold 2, and a center of the bottom surface of the crucible molding mold 2 that faces the duct joining section 5C. A second cooling unit 6b that covers the cooling unit, a water supply / drainage pump 6c for supplying water to the cooling units 6a, 6b and draining them, the water supply / drainage pump 6c, and the cooling units 6a, 6b (water supply) A coupling 6d for connecting the pipe and the drain pipe), and is disposed outside the crucible molding die 2 (ventilation duct). Thereby, the said crucible shaping | molding die 2 can be cooled and the deformation | transformation and oxidation of the said crucible shaping | molding die 2 can be prevented.
The first cooling part 6 a is a cylindrical part having a rotation axis of the crucible molding die 2 as a central axis, and is connected to the coupling 6 d via a water supply pipe 16 and a drain pipe 17. And it is comprised so that the outer peripheral part of the said crucible shaping | molding type | mold 2 may be cooled.
[0028]
As shown in FIGS. 6 (a) and 6 (b), the second cooling part 6b is formed of a cylindrical part having the rotation axis o of the crucible molding die 2 as a central axis, as with the first cooling part 6a. The coupling 6d is connected via a water supply pipe 14 and a drain pipe 15. And it is comprised so that the said 2nd ventilation duct 5b may be inserted, and the bottom face center part of the said crucible shaping | molding die 2 may be covered, and the bottom face center part of the said crucible shaping | molding die 2 is cooled. The inner diameter of the second cooling part 6b is set to 15 to 50% of the inner diameter of the crucible molding die 2. In this case, the center part of the bottom surface of the crucible molding die 2 can be more accurately cooled by setting the inner diameter of the second cooling portion 6b to 15% or more of the inner diameter of the crucible molding die 2. Moreover, by making it 50% or less, it is possible to ensure that the transparent layer thickness in the curved portion 2d and the bubble distribution of the opaque layer are equivalent to those of other parts, and to obtain higher homogeneity in the entire quartz glass crucible. be able to.
[0029]
The water supply / drainage pump 6c is connected to the coupling 6d via a water supply pipe 13, and supplies the cooling water to both the cooling units 6a, 6b and can discharge the supply water from the drainage pipe 20. It is configured as follows.
The coupling 6d includes a rotating portion 18 that rotates together with the motor shaft 4a and a fixing portion 19 that holds the rotating portion 18, and is disposed above the driving means 4. The feed / drain pump 6 c and the feed pipes 14, 16 are connected by the feed pipe 13, and the drain pipe 20 is communicated with the drain pipes 15, 17. Further, the coupling 6d is configured to couple the rotating duct portion 5D and the fixed duct portion 5E.
In addition, the arrow in the figure shows the flow direction of the cooling water in the pipe.
[0030]
With the above configuration, the outer peripheral portion of the crucible molding die 2 is particularly cooled by the first cooling portion 6a, and the bottom center portion of the crucible molding die 2 is cooled by the second cooling portion 6b. Therefore, in this embodiment, not only the outer peripheral portion of the crucible molding die 2 but also the central portion of the bottom surface thereof is sufficiently cooled, so that these portions are difficult to oxidize during crucible molding (heating), and molding by oxide Contamination of the product can be prevented.
[0031]
In the present embodiment, the first through hole 2b is provided in the outer periphery of the crucible molding die 2 and the second through hole 2c is provided in the center of the bottom surface. Since a sufficient suction (decompression) force is secured in the central portion, the thickness of the transparent layer of the molded product and the bubble distribution of the opaque layer become uniform, and a molded product having uniform characteristics can be obtained.
Furthermore, in the present embodiment, ensuring that sufficient decompression force is secured at the outer peripheral portion and the bottom center portion of the crucible molding die 2 is that the bottom center portion of the molded product rises with an increase in the diameter of the molded product, or When a round bottom molded product is manufactured, a molded product having a flat bottom is not formed, and a molded product having a desired shape can be obtained.
[0032]
In addition, manufacture of the quartz glass crucible using the quartz glass crucible manufacturing apparatus 1 in this embodiment is performed as follows.
First, the crucible molding die 2 is rotated at a high speed by driving the driving means 4 and the quartz glass raw material powder M is supplied into the crucible molding die 2. In this case, with the rotation of the crucible molding die 2, a part of the quartz glass raw material powder M moves to the inner peripheral surface of the crucible molding die 2 by centrifugal force to form a layered quartz glass raw material powder M. The remaining quartz glass raw material powder M is laminated on the inner bottom surface of the crucible molding die 2 by gravity.
[0033]
Then, the suction means 5 is driven in the atmosphere to suck the inside of the crucible molding die 1, and the heating means 3 is energized almost simultaneously with the suction process to heat and melt the layered quartz glass raw material powder M. In this case, when the layered quartz glass raw material powder M is heated and melted, the inside part of the quartz glass raw material powder layer is made of only extremely small bubbles, and a substantially bubble-free state is achieved. A double-layer quartz glass crucible (molded product) in which bubbles are present is produced. On the other hand, the air in the crucible molding die 2 is sucked into the through holes 2b and 2c through the layered quartz glass raw material powder M, and the air-permeable filter 8 in both the through holes 2b and 2c (hole part 2B). The air is drawn into the exhaust passage 10 of the first ventilation duct 5a and the exhaust passage 10a of the second ventilation duct 5b, and is discharged out of the quartz glass crucible manufacturing apparatus 1 through the common passage 11 of the third ventilation duct 5c. .
[0034]
In this heating and melting, the first cooling part 6a is used for the outer peripheral part of the crucible molding die 2 and the second cooling part 6b is used for crucible molding by supplying cooling water by the driving action of the feed / drain pump 6d. The bottom center part of the mold 2 is cooled.
Thereby, a quartz glass crucible is manufactured.
[0035]
In the present embodiment, the through holes 2b and 2c for accommodating the air permeable filter 8 are large, medium and small three holes 2A to 2C and between the holes 2A and 2B and between the holes 2B and 2C. Although the case where the stepped holes are formed by the surfaces 2D and 2E has been described, the present invention is not limited to this, and even the one formed by two large and small hole portions (not shown) has the same effect as the embodiment. In this case, the mounting screw is screwed into the large-diameter hole with the air-permeable filter pressed against the filter mounting surface between the two holes.
In the present embodiment, the case where the intake gas passes through the rotating duct portion 5D of the third ventilation duct 5c has been described. However, the present invention is not limited to this, and the passage portion passes through the space portion 4A of the motor shaft 4a. May be. In this case, the rotating duct portion 5D becomes unnecessary.
[0036]
【The invention's effect】
As is clear from the above description, according to the quartz glass crucible manufacturing apparatus according to the present invention, it is possible to prevent the molded product from being contaminated and to obtain a molded product having uniform characteristics and a desired shape.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an entire quartz glass crucible manufacturing apparatus to which the present invention is applied.
FIG. 2 is an enlarged cross-sectional view showing a main part of a quartz glass crucible manufacturing apparatus to which the present invention is applied.
3 is a cross-sectional view taken along the line AA in FIG.
FIG. 4 is a perspective view showing a crucible molding die of a quartz glass crucible manufacturing apparatus to which the present invention is applied.
FIGS. 5A and 5B are perspective views showing a mounting screw and a breathable filter of a quartz glass crucible manufacturing apparatus to which the present invention is applied.
FIGS. 6A and 6B are a cross-sectional view schematically showing a crucible molding die of a quartz glass crucible manufacturing apparatus to which the present invention is applied, and a cross-sectional view taken along the line BB in FIG.
FIG. 7 is a cross-sectional view showing a conventional quartz glass crucible manufacturing apparatus.
FIGS. 8A and 8B are cross-sectional views showing examples of defective molding by a conventional quartz glass crucible manufacturing apparatus. FIGS.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Quartz glass crucible manufacturing apparatus 2 Crucible shaping | molding type | mold 2a Space part 2b 1st through-hole 2c 2nd through-hole 2A-2C Hole 2E Filter attachment surface 3 Heating means 4 Drive means 4a Motor shaft 4A Space part 5 Intake means 5a 1st One ventilation duct 5b Second ventilation duct 5c Third ventilation duct 5d Suction pump 5A Straight duct part 5B Curved duct part 5C Duct merge part 5D Rotating duct part 5E Fixed duct part 6 Cooling means 6a First cooling part 6b Second cooling part 6c Water supply / drainage pump 6d Coupling 7 Mounting screw 7a Screw part 7b Exhaust hole 8 Breathable filter 10, 10a Exhaust path 11 Common flow path 13, 14, 16 Water supply pipes 15, 17, 20 Drain pipe

Claims (7)

A bottomed cylindrical body for forming a quartz glass crucible by supplying quartz glass raw material powder for crucible molding, the first through hole opening in the outer peripheral portion of the bottomed cylindrical body and opening in the center of the bottom surface A crucible molding die having a second through hole that has a central axis as a rotation axis;
An air intake means disposed outside the crucible mold and having a first ventilation duct communicating with the first through hole and a second ventilation duct communicating with the second through hole;
A cooling means disposed outside the ventilation duct of the intake means, and for cooling the crucible molding die,
In this cooling means, a first cooling part that covers the outer periphery of the first ventilation duct and the crucible molding die, and
An apparatus for producing a quartz glass crucible, comprising: a second cooling part that is inserted through the second ventilation duct and covers a bottom center part of the crucible molding die. 2. The quartz glass crucible manufacturing apparatus according to claim 1, wherein both the cooling parts are formed of cylindrical parts located concentrically with a rotation axis of the crucible forming mold as a central axis. The quartz glass crucible manufacturing apparatus according to claim 2, wherein an inner diameter of the second cooling unit is set to 15 to 50% of an inner diameter of the crucible molding die. The quartz glass crucible manufacturing apparatus according to any one of claims 1 to 3, wherein a bulging portion having a space for allowing the second cooling portion to face is provided in the first ventilation duct. . The through hole is formed by a stepped hole having a plurality of holes having different diameters and a filter mounting surface interposed between two adjacent holes among these holes,
The quartz glass crucible manufacturing apparatus according to any one of claims 1 to 4, wherein a mounting screw for press-fitting the air-permeable filter is screwed onto the filter mounting surface in the stepped hole. . The quartz glass crucible manufacturing apparatus according to claim 5, wherein a diameter of the mold side hole portion of the holes is set to be larger than a diameter of the duct side hole portion. The mounting screw is formed by a disk-shaped filter mounting member having a screw portion screwed into an inner peripheral surface of the through hole and a flat hexagonal exhaust hole opened in the axial direction. The quartz glass crucible manufacturing apparatus according to claim 5 or 6.

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