JP4161804B2 - Heat shielding member of silicon single crystal pulling device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat shielding member provided in an apparatus for pulling and growing a silicon single crystal rod.
[0002]
[Prior art]
Conventionally, as this type of silicon single crystal pulling apparatus, a quartz crucible in which a silicon melt is stored in a chamber is accommodated, and a silicon single crystal rod is interposed between the outer peripheral surface of the silicon single crystal rod and the inner peripheral surface of the quartz crucible. A pulling device (see, for example, Patent Document 1) in which a heat shielding member is inserted so as to surround the frame is disclosed. The heat shielding member in this apparatus is made of thermally stable graphite, surrounds the outer peripheral surface of the silicon single crystal rod to be pulled up, and the lower end is located above the surface of the silicon melt and radiates heat from the heater. It has a blocking cylinder. The heat shielding member is configured to smoothly guide the inert gas flowing between the outer peripheral surface of the silicon single crystal rod and the inner peripheral surface of the cylindrical portion. In this pulling device, the heat shielding member blocks the radiant heat from the exposed inner wall of the quartz crucible, thereby preventing the radiant heat from reaching the outer peripheral surface of the silicon single crystal rod and solidifying the silicon single crystal rod being pulled. The silicon single crystal rod is promptly cooled.
[0003]
On the other hand, the temperature distribution in the vicinity of the silicon melt in the silicon single crystal rod pulled up from the silicon melt is highest at the center and gradually lowers toward the outer surface because of the large amount of heat released from the outer surface of the silicon single crystal rod. And rapidly decreases at the outer periphery. In particular, when the diameter of the silicon single crystal rod is increased, the temperature difference between the center portion and the outer peripheral portion of the silicon single crystal rod is expected to be further increased. For this reason, there is a possibility that thermal stress based on the temperature difference is generated in the silicon single crystal rod. For this reason, a ring-shaped heat storage member is formed in the lower portion of the cylinder portion so as to bulge in the direction in the cylinder and surround the lower outer peripheral surface of the silicon single crystal rod inside the bulge portion. A heat shielding member for a provided silicon single crystal pulling apparatus has been proposed (see, for example, Patent Document 2). In this heat shielding member, the heat radiation from the silicon single crystal rod is reflected by the bulging portion, or the bulging portion itself rises in temperature by a high-temperature heater and silicon melt, so that the outer peripheral portion of the silicon single crystal rod The temperature distribution in the silicon single crystal rod can be made substantially uniform from the center to the outer peripheral surface to suppress the occurrence of thermal stress in the silicon single crystal rod. .
[0004]
[Patent Document 1]
Japanese Patent Publication No.57-40119 [Patent Document 2]
Japanese Patent Laid-Open No. 2000-24776
[Problems to be solved by the invention]
However, in the heat shielding member having the bulging portion, SiO melts when the silicon raw material melts or the silicon raw material is supplied and the silicon melt adheres to the lower surface of the bulging portion or evaporates from the silicon melt surface. The bulge is exposed to gas. As the graphite on the lower surface is converted to SiC, deterioration of the surface of the bulging portion occurs. In particular, silicon deposits are likely to adhere to the lower surface of the bulging portion. When the material of the surface of the bulging portion is deteriorated, the heat radiation rate is changed, and the characteristics of the heat shielding member are changed, thereby causing a problem that the quality of the silicon single crystal rod pulled up is changed with time. Moreover, the deposit | attachment adhering to the bulging part may fall into a melt during pulling up, and there exists a malfunction which a silicon single crystal rod becomes dislocation.
In order to solve this problem, the entire heat shielding member is replaced and pulled up before it affects the quality of the silicon single crystal rod due to the deterioration of the lower surface of the bulging portion of the shielding member. The quality of the crystal rod is made uniform. However, replacing the entire heat shielding member, despite including the originally effective portion, has a problem of raising the cost of pulling up the silicon single crystal rod.
An object of the present invention is to provide a heat shielding member of a silicon single crystal pulling apparatus capable of exchanging only a bottom portion of a bulging portion, which is easily deteriorated when the silicon single crystal is pulled many times.
[0006]
[Means for Solving the Problems]
As shown in FIG. 3, the invention according to claim 1 draws the silicon single crystal rod 25 from the silicon melt 12 heated by the heater 18 surrounding the outer peripheral surface of the quartz crucible 13 and stored in the quartz crucible 13. An outer cylinder member 34 which is provided in a lifting device and whose lower end is positioned above the surface of the silicon melt 12 and which surrounds the outer peripheral surface of the silicon single crystal rod 25 and shields radiant heat from the heater 18; A bulging portion 41 that bulges in the direction of the cylinder in the lower portion of the member 34; a ring-shaped heat storage member 47 that is provided inside the bulging portion 41 and surrounds the lower outer peripheral surface of the silicon single crystal rod 25; It is improvement of the heat shielding member provided with.
As shown in FIG. 1, the characteristic structure is that a flange 34a is formed on the entire inner periphery of the lower portion of the outer cylinder member 34, and the bulging portion 41 is inserted into the outer cylinder member 34 from the upper side, and the outer periphery is flange 34a. A ring-shaped bottom wall 42 whose inner periphery reaches the vicinity of the outer peripheral surface of the silicon single crystal rod 25, and a cylindrical vertical wall that is inserted into the outer cylinder member 34 from above and has a lower edge closely contacting the inner periphery of the bottom wall 42. A wall 44 and an upper wall 46 that is formed integrally with the vertical wall 44 at the upper edge of the vertical wall 44 and that is integrally formed with the vertical wall 44 are connected to the outer cylinder member 34 . A stepped portion 42a equal to the thickness of the flange 34a is formed in the lower outer periphery, and the outer peripheral surface of the stepped portion 42a faces the inner peripheral surface of the flange 34a in a state where the outer periphery of the bottom wall 42 is installed on the flange 34a. Is formed to form a joint line, Protrusions 44a protruding is formed on the entire circumference, the inner circumferential ridge 44a can be inserted into a groove 42b of the bottom wall 42 is in place, which is formed on the entire circumference.
[0007]
In the heat shielding member of the silicon single crystal pulling apparatus according to the first aspect, the bottom wall 42 deteriorates and deteriorates after the silicon single crystal is pulled many times. In this case, as shown in FIG. 2, the integrally formed vertical wall 44 and upper wall 46 are moved upward to once remove them from the outer cylinder member 34, and subsequently take out the heat storage member 47, and then change the quality. The bottom wall 42 is moved upward and taken out from the outer cylinder member 34. Next, a new bottom wall 42 is inserted into the outer cylinder member 34 from above, and the outer periphery thereof is installed on a flange 34 a formed at the bottom of the outer cylinder member 34. Thereafter, the heat storage member 47, the vertical wall 44, and the upper wall 46 once taken out are sequentially inserted into the outer cylinder member 34 from above, and the lower end of the vertical wall 44 is brought into close contact with the inner periphery of the bottom wall 42. In this way, it is possible to replace only the bottom wall 42 that easily deteriorates and deteriorates when the silicon single crystal is pulled many times, and it is possible to continue using it without replacing other portions.
And the degassing and particle | grains which arise from the thermal storage member 47 provided in the bulging part 41 can be suppressed from being discharged | emitted outside from this junction part, The silicon single crystal rod 25 pulled up resulting from these Can be prevented from being rearranged or contaminated.
[0008]
The invention according to claim 2 is the invention according to claim 1, wherein an inner cylinder member 37 provided concentrically with the outer cylinder member 34 at a predetermined interval from the outer cylinder member 34, and the outer cylinder member 34 And a heat insulating material 38 interposed between the inner cylinder members 37, and the inner cylinder member 37 has a lower end continuous to the outer periphery of the upper wall 46 and is formed integrally with the upper wall 46 and the vertical wall 44. It is a heat shielding member of a single crystal pulling apparatus.
In the heat shielding member of the silicon single crystal pulling apparatus described in claim 2, the inner cylindrical member 37 and the heat insulating material 38 effectively shield the radiant heat from the inner peripheral wall of the heater 18 and the quartz crucible 13 toward the silicon single crystal rod 25. Cooling of the silicon single crystal rod 25 pulled up beyond the bulging portion 41 can be promoted. Further, by forming the inner cylinder member 37 integrally with the upper wall 46, the inner cylinder member 37 can be removed together with the upper wall 46 when the bottom wall 42 is replaced, which hinders the replacement operation. There is nothing.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 3, a quartz crucible 13 for storing a silicon melt 12 is provided in the chamber 11 of the silicon single crystal pulling apparatus 10, and the outer peripheral surface of the quartz crucible 13 is covered with a graphite susceptor 14. . The lower surface of the quartz crucible 13 is fixed to the upper end of the support shaft 16 via the graphite susceptor 14, and the lower portion of the support shaft 16 is connected to the crucible driving means 17. Although not shown, the crucible driving means 17 has a first rotating motor for rotating the quartz crucible 13 and a lifting motor for moving the quartz crucible 13 up and down, and the quartz crucible 13 can be rotated in a predetermined direction by these motors. At the same time, it is movable in the vertical direction. The outer peripheral surface of the quartz crucible 13 is surrounded by a heater 18 at a predetermined interval from the quartz crucible 13, and the heater 18 is surrounded by a heat retaining cylinder 19. The heater 18 heats and melts the high-purity silicon polycrystal charged in the quartz crucible 13 to form the silicon melt 12.
[0011]
A cylindrical casing 21 is connected to the upper end of the chamber 11. The casing 21 is provided with a pulling means 22. The pulling means 22 is a pulling head (not shown) provided at the upper end of the casing 21 so as to be turnable in a horizontal state, a second rotating motor (not shown) for rotating the head, and a quartz crucible 13 from the head. And a pulling motor (not shown) that is provided in the head and winds or feeds the wire cable 23. A seed crystal 24 is attached to the lower end of the wire cable 23 to immerse the silicon single crystal rod 25 in the silicon melt 12.
Further, a gas supply / discharge means 28 for supplying an inert gas to the silicon single crystal rod side of the chamber 11 and discharging the inert gas from the crucible inner peripheral surface side of the chamber 11 is connected to the chamber 11. The gas supply / discharge means 28 has one end connected to the peripheral wall of the casing 21 and the other end connected to a tank (not shown) for storing the inert gas, and one end connected to the lower wall of the chamber 11. The other end has a discharge pipe 30 connected to a vacuum pump (not shown). The supply pipe 29 and the discharge pipe 30 are respectively provided with first and second flow rate adjusting valves 31 and 32 for adjusting the flow rate of the inert gas flowing through the pipes 29 and 30.
[0012]
On the other hand, an encoder (not shown) is provided on the output shaft (not shown) of the pulling motor, and an encoder (not shown) for detecting the raising / lowering position of the support shaft 16 is provided on the crucible driving means 17. Each detection output of the two encoders is connected to a control input of a controller (not shown), and the control output of the controller is connected to a lifting motor of the pulling means 22 and a lifting motor of the crucible driving means. The controller is also provided with a memory (not shown), and the memory stores the winding length of the wire cable 23 with respect to the detection output of the encoder, that is, the pulling length of the silicon single crystal rod 25 as a first map. . Further, the memory stores the liquid level of the silicon melt 12 in the quartz crucible 13 with respect to the pulled length of the silicon single crystal rod 25 as a second map. The controller is configured to control the raising / lowering motor of the crucible driving means 17 so as to always keep the liquid level of the silicon melt 12 in the quartz crucible 13 at a constant level based on the detection output of the encoder in the pulling motor. Is done.
[0013]
Between the outer peripheral surface of the silicon single crystal rod 25 and the inner peripheral surface of the quartz crucible 13, a heat shielding member 33 that surrounds the outer peripheral surface of the silicon single crystal rod 25 is provided. The heat shielding member 33 is formed in a cylindrical shape and includes an outer cylinder member 34 that shields radiant heat from the heater 18, and a flange portion 36 that is connected to the upper edge of the outer cylinder member 34 and projects outward in a substantially horizontal direction. Have. By placing the flange portion 36 on the heat retaining cylinder 19, the heat shielding member 33 is fixed in the chamber 11 so that the lower edge of the outer cylinder member 34 is located a predetermined distance above the surface of the silicon melt 12. Is done. As shown in FIG. 1, an inner cylinder member 37 configured to be spaced apart from the outer cylinder member 34 is inserted into the outer cylinder member 34, and the inner cylinder member 37 is concentric with the outer cylinder member 34. Is provided. A heat insulating material 38 is filled between the outer cylinder member 34 and the inner cylinder member 37. In this embodiment, the outer cylindrical member 34 is a cone-shaped cylindrical body whose diameter is reduced downward, and the heat insulating material 38 is made of a felt material made of carbon fiber. A bulging portion 41 that bulges in the direction of the cylinder is provided at the lower portion of the outer cylinder member 34.
[0014]
As shown in FIG. 1, the bulging portion 41 includes a ring-shaped bottom wall 42, a cylindrical vertical wall 44, and an upper wall 46 that is connected to the upper edge of the vertical wall 44. The outer diameter of the ring-shaped bottom wall 42 is formed to be substantially the same as or slightly smaller than the lower inner diameter of the outer cylinder member 34, and a flange 34 a is formed on the entire inner circumference of the lower inner periphery of the outer cylinder member 34. Is done. A step portion 42a having a thickness equal to the thickness of the flange 34a is formed on the outer periphery of the bottom wall 42. The ring-shaped bottom wall 42 is inserted into the outer cylindrical member 34 from the upper side, and the outer periphery thereof is installed on the flange 34a. The In the state where the outer periphery of the bottom wall 42 is installed on the flange 34a, the outer peripheral surface of the stepped portion 42a is opposed to the inner peripheral surface of the flange 34a to form a crank-shaped joint line. On the other hand, the inner periphery of the bottom wall 42 is formed so as to reach the vicinity of the outer peripheral surface of the silicon single crystal rod 25 to be pulled up, and the cylindrical vertical wall 44 has an inner diameter substantially equal to the inner diameter of the bottom wall 42 formed in a ring shape. Formed identically. The vertical wall 44 is inserted into the outer cylinder member 34 from the upper side with the outer periphery of the bottom wall 42 installed on the flange 34 a, and the lower edge is in close contact with the inner periphery of the bottom wall 42.
[0015]
Here, the lower edge of the vertical wall 44 is formed with a protruding ridge 44a that protrudes downward, and the groove 42b into which the ridge 44a can be inserted on the inner periphery of the bottom wall 42 facing the lower edge. Is formed all around. The protrusion 44a is inserted into the concave groove 42b with the lower end of the vertical wall 44 in contact with the inner periphery of the bottom wall 42, whereby the lower edge of the vertical wall 44 and the inner periphery of the bottom wall 42 are brought into close contact with each other. The upper wall 46 is formed integrally with the vertical wall 44 by connecting the inner periphery to the upper edge of the vertical wall 44. The lower end of the inner cylinder member 37 is connected to the outer periphery of the upper wall 46, and the inner cylinder member 37 is formed integrally with the upper wall 46 and the standing wall 44. A ring-shaped flange 37a is formed outward at the upper end of the inner cylinder member 37, and a step 34b on which the outer periphery of the flange 37a is installed is formed at the upper end of the outer cylinder member 34. By installing the outer periphery of the flange 37a on the step portion 34b, a joint surface having a crank-like cross section at the connection portion between the upper portion of the inner cylinder member 37 and the upper portion of the outer cylinder member 34 is formed. The outer periphery of the upper wall 46 is connected to the outer cylinder member 34 via the inner cylinder member 37. The inner cylinder member 37, the outer cylinder member 34, the bottom wall 42, the vertical wall 44, and the upper wall 46 are preferably made of thermally stable and high-purity graphite or graphite whose surface is coated with SiC. It is also possible to use materials such as Mo (molybdenum) and W (tungsten) which are stable.
[0016]
A ring-shaped heat storage member 47 is provided inside the bulging portion 41 surrounded by the lower portion of the outer cylinder member 34, the bottom wall 42, the vertical wall 44, and the upper wall 46. The heat storage member 47 in this embodiment is formed by filling the bulging portion 41 with a felt material of 0.05 to 0.50 g / cm ³ made of carbon fiber, and this carbon fiber is used as the heat storage member 47. By using it, the thermal conductivity of the heat storage member 47 is limited to 5 W / (m · ° C.) or less. However, the heat storage member 47 is not limited to the felt material made of carbon fiber, and a heat insulating material such as alumina can be used as long as the thermal conductivity is 5 W / (m · ° C.) or less.
[0017]
The operation of the silicon single crystal pulling apparatus configured as described above will be described.
In the heat shielding member 33 of the silicon single crystal pulling apparatus according to the present embodiment, the periphery of the silicon single crystal rod 25 in the vicinity of the silicon melt 12 below the bulging portion 41 is positively affected by the high-temperature heater 18 and the silicon melt 12. To be heated. On the other hand, the heat storage member 47 provided inside the bulging portion 41 is also positively heated by the high-temperature heater 18 and the silicon melt 12, and the periphery of the silicon single crystal rod 25 facing the bulging portion 41 is heated. The heat storage member 47 is heated. As a result, a rapid temperature drop in the lower outer peripheral portion of the silicon single crystal rod 25 is prevented, and the radial distribution of the temperature gradient in the axial direction of the silicon single crystal rod 25 in this portion becomes substantially uniform. According to the model, the silicon single crystal rod 25 in which no glow-in defect is detected can be manufactured.
[0018]
When the silicon single crystal rod 25 is manufactured, the molten silicon splashes when the silicon raw material is melted or the silicon raw material is supplied, and the silicon melt adheres to the lower surface of the bulging portion 41, or the SiO gas evaporates from the silicon melt surface. The bulging part 41 is exposed. Therefore, when the production of the silicon single crystal rod 25 is repeated, the graphite of the bottom wall 42 constituting the lower surface of the bulging portion 41 is converted to SiC, so that the bottom wall 42 is deteriorated and deteriorated. On the other hand, the amount of silicon melt adhering to the other portions, that is, the outer cylindrical member 34, the vertical wall 44, the upper wall 46, and the inner cylindrical member 37 and the amount exposed to the SiO gas is smaller than that of the bottom wall 42. Therefore, these portions are less likely to be degenerated than the bottom wall 42, and even if the bottom wall 42 is denatured, it can be used sufficiently. Further, the silicon melt splash tends to adhere to the bottom wall 42.
[0019]
For this reason, by exchanging only the bottom wall 42 that easily deteriorates when the silicon single crystal is pulled many times, other portions can be used continuously without being exchanged. In order to replace the bottom wall 42, as shown in FIG. 2, the integrally formed vertical wall 44, upper wall 46, and inner cylinder member 37 are moved upward to be temporarily removed from the outer cylinder member 34, and subsequently. After the heat insulating material 38 and the heat storage member 47 are taken out in this order, the altered bottom wall 42 is moved upward and taken out from the outer cylinder member 34. Next, a new bottom wall 42 is inserted into the outer cylinder member 34 from above, and the outer periphery thereof is installed on a flange 34 a formed at the bottom of the outer cylinder member 34. Thereafter, the heat storage member 47 and the heat insulating material 38 once taken out are inserted in this order. Further, the vertical wall 44, the upper wall 46 and the inner cylinder member 37 are inserted into the outer cylinder member 34 from above, and a ridge 44 a formed at the lower end of the vertical wall 44 is formed into a groove 42 b formed on the inner periphery of the bottom wall 42. The bottom edge of the vertical wall 44 and the inner periphery of the bottom wall 42 are brought into close contact with each other. In this way, it is possible to replace only the bottom wall 42 which is easily deteriorated when the silicon single crystal is pulled many times, and the cost of the heat shielding member is reduced as compared with the conventional case where the entire heat shielding member is replaced, The silicon single crystal rod 25 can be pulled up at a relatively low cost.
[0020]
Further, in this embodiment, a step portion 34b on which the outer periphery of the flange 37a formed at the upper end of the inner cylinder member 37 is installed is formed at the upper end of the outer cylinder member 34, and the upper portion of the inner cylinder member 37 and the outer cylinder member Since a joint surface having a crank-shaped cross section is formed at the connection point with the upper portion of 34, degassing and particles generated from the heat insulating material 38 interposed between the outer cylinder member 34 and the inner cylinder member 37 are exposed to the outside from the joint portion. Release can be suppressed. The bottom wall 42 is configured to form a crank-shaped joint line with the outer periphery of the bottom wall 42 being installed on the flange 34 a, and the ridge 44 a formed on the lower edge of the vertical wall 44 is connected to the inner periphery of the bottom wall 42. Therefore, it is possible to suppress degassing and particles generated from the heat storage member 47 provided inside the bulging portion 41 from being released to the outside from the joint portion. As a result, it is possible to prevent dislocation or contamination of the silicon single crystal rod 25 that is pulled up due to degassing or leakage of particles.
[0021]
In the above embodiment, the outer cylinder member 34 is formed in a hollow truncated cone shape whose diameter decreases as it goes downward, but the outer cylinder member 34 may be formed in a cylindrical shape.
Moreover, in the said embodiment, although the heat insulating material 38 was filled between the inner cylinder member 37 and the outer cylinder member 34, as long as the heat shielding effect in the outer cylinder member 34 is enough, the inner cylinder member 37 and the heat insulating material 38 are It does not necessarily have to be provided.
[0022]
【The invention's effect】
As described above, according to the present invention, the flange is formed on the entire inner periphery of the lower portion of the outer cylinder member, the outer periphery of the ring-shaped bottom wall is installed on the flange, and the vertical wall is formed on the inner periphery of the bottom wall. Since the bulge is formed by connecting the outer periphery of the upper wall with the inner periphery connected to the upper edge of the vertical wall in close contact with the upper edge of the vertical wall, the vertical wall and the upper wall are moved upward Then, take out from the outer cylinder member once, then take out the heat insulating material and the heat storage member, and then move the bottom wall upward to remove the bottom wall constituting the lower part of the bulging portion relatively easily from the outer cylinder member. Can do. Then, a new bottom wall is inserted into the outer cylinder member from above, and the outer periphery thereof is installed on the flange formed on the bottom of the outer cylinder member. Thereafter, the heat storage member and the heat insulating material once taken out are inserted, and the vertical wall and Only the bottom wall can be replaced by inserting the upper wall into the outer cylinder member from above and bringing the lower end of the vertical wall into close contact with the inner periphery of the bottom wall. As a result, the other parts can be used continuously without replacement, and the cost of pulling up the silicon single crystal rod can be reduced.
[0023]
Further, if the inner cylinder member provided concentrically with the outer cylinder member at a predetermined interval from the outer cylinder member, and a heat insulating material interposed between the outer cylinder member and the inner cylinder member, the inner cylinder The member and the heat insulating material can effectively block the radiant heat from the inner peripheral wall of the heater or the quartz crucible toward the silicon single crystal rod, and the cooling of the silicon single crystal rod pulled up beyond the bulging portion can be promoted. In this case, if the inner cylinder member is formed integrally with the upper wall and the vertical wall by connecting the lower end to the inner periphery of the upper wall, the inner cylinder member can be removed together with the upper wall when replacing the bottom wall. It is possible to prevent the replacement work from being hindered.
Furthermore, if a convex ridge protruding downward is formed on the lower edge of the vertical wall on the entire circumference, and a concave groove on the inner periphery of the bottom wall is formed on the entire circumference, it is provided inside the bulging portion. The degassing and particles generated from the heat storage member can be prevented from being released to the outside from this joint, and the silicon single crystal rod pulled up due to these can be dislocated or contaminated. Can be prevented.
[Brief description of the drawings]
FIG. 1 is an enlarged cross-sectional view of a part A in FIG. 3 showing a heat shielding member 33 of a silicon single crystal pulling apparatus according to the present invention.
FIG. 2 is an exploded configuration diagram showing the configuration of the heat shielding member.
FIG. 3 is a cross-sectional configuration diagram of the silicon single crystal pulling apparatus.
[Explanation of symbols]
13 Quartz crucible 12 Silicon melt 18 Heater 25 Silicon single crystal rod 34 Outer cylinder member 34a Flange 37 Inner cylinder member 38 Insulating material 41 Swelling part 42 Bottom wall 42b Groove 44 Vertical wall 44a Projection 46 Top wall 47 Heat storage member

Claims (2)

Provided in a device for pulling up the silicon single crystal rod (25) from the silicon melt (12) stored in the quartz crucible (13) by being heated by a heater (18) surrounding the outer peripheral surface of the quartz crucible (13). An outer cylinder member whose lower end is located above and spaced from the surface of the silicon melt (12) and surrounds the outer peripheral surface of the silicon single crystal rod (25) to block radiant heat from the heater (18) ( 34), a bulge portion (41) provided to bulge in the direction of the cylinder at the lower portion of the outer cylinder member (34), and the silicon single crystal rod provided inside the bulge portion (41) In a heat shielding member comprising a ring-shaped heat storage member (47) surrounding the lower outer peripheral surface of (25),
A flange (34a) is formed on the entire inner periphery of the lower inner periphery of the outer cylinder member (34),
The bulging portion (41) is inserted into the outer cylinder member (34) from the upper side, the outer periphery is installed on the flange (34a), and the inner periphery reaches the vicinity of the outer peripheral surface of the silicon single crystal rod (25). The bottom wall (42) of the
A cylindrical vertical wall (44) inserted from above into the outer cylinder member (34) and having a lower edge in close contact with the inner periphery of the bottom wall (42),
The upper wall (46) is connected to the outer cylinder member (34) by forming an inner periphery continuously with the upper edge of the vertical wall (44) and integrally forming with the vertical wall (44). It is,
A step portion (42a) equal to the thickness of the flange (34a) is formed at the lower outer periphery of the bottom wall (42), and the outer periphery of the bottom wall (42 ) is installed on the flange (34a). The outer peripheral surface of the stepped portion (42a) is configured to form a joint line having a crank-shaped cross section facing the inner peripheral surface of the flange (34a) ,
A ridge (44a) projecting downward is formed on the entire periphery of the lower edge of the vertical wall (44) ,
A heat shielding member for a silicon single crystal pulling apparatus , wherein a groove (42b) into which the protrusion (44a) can be inserted is formed on the inner periphery of the bottom wall (42) . An inner cylinder member (37) provided concentrically with the outer cylinder member (34) at a predetermined interval from the outer cylinder member (34), and the outer cylinder member (34) and the inner cylinder member (37). A heat insulating material (38) interposed therebetween,
The silicon single crystal pulling-up method according to claim 1, wherein the inner cylindrical member (37) is formed integrally with the upper wall (46) and the vertical wall (44) with a lower end provided continuously with an outer periphery of the upper wall (46). Heat shield member of the device.

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