JP2006069803A - Heat-shielding member for silicon single crystal pulling apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To relatively easily change the required shielding amount of heat radiation. <P>SOLUTION: The heat-shielding member is installed in an apparatus for pulling a silicon single crystal rod 25 from a silicon melt 12 stored in a quartz crucible 13. The heat-shielding member is equipped with a cylindrical part 37 whose lower end is located at an upper part of the surface of the silicon melt 12 with an interval from the surface and which surrounds the outer peripheral surface of the silicon single crystal rod; a bulged part 41 installed at a lower part of the cylindrical part 37 bulging toward the inside of the cylinder; a ring-like heat-insulating cover 51 which is constituted in an insertable/removable way at the inside of the cylinder and surrounds the outer peripheral surface of the silicon single crystal rod in a state that it is inserted inside the cylindrical part 37; and a supporting member 56 which supports the heat-insulating cover 51 inserted inside the cylindrical part 37 at an upper part of the bulged part 41 with a prescribed interval from the bulged part 41. The supporting member 56 is constituted of a plurality of projected parts 56 provided at the inner surface of the cylindrical part 37, and a plurality of notched parts 51a are formed at the outer peripheral surface of the ring-like heat-insulating cover 51 corresponding to the projected parts 56 so that the heat-insulating cover 51 can pass through the projected parts 56 when it is inserted. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat shielding member provided in an apparatus for pulling up and growing a silicon single crystal rod so as to surround the silicon single crystal rod.

  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 surrounds the outer peripheral surface of the silicon single crystal rod to be pulled up, and the lower end is located above the silicon melt surface and is located above the cylindrical portion which shields the radiant heat from the heater, and the lower portion of the cylindrical portion The heat shielding member smoothly flows the inert gas flowing down between the outer peripheral surface of the silicon single crystal rod and the inner peripheral surface of the cylindrical portion. Configured to guide. 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.

On the other hand, in the process of manufacturing a semiconductor integrated circuit, the cause of lowering the yield is due to micro-defects of oxygen precipitates that are the core of oxidation-induced stacking faults (hereinafter referred to as OSFs) or crystals. The presence of particles (Crystal Originated Particles, hereinafter referred to as COP) or interstitial-type large dislocations (hereinafter referred to as L / D), and silicon used for manufacturing semiconductor integrated circuits From the wafer, it is necessary to reduce these OSF, COP and L / D.
In order to cut out a defect-free silicon wafer having no OSF, COP, and L / D, a silicon single crystal rod manufacturing method based on the Boronkov theory has been proposed (for example, see Patent Document 2). .) In this Voronkov theory, when a silicon single crystal rod is pulled up at a high speed, a region [V] in which agglomerates of vacancy-type point defects exist dominantly in the silicon single crystal rod is formed. When the single crystal rod is pulled at a low speed, a region [I] in which aggregates of interstitial silicon type point defects exist predominantly in the silicon single crystal rod is formed. For this reason, the bulge part provided in the lower part of the cylindrical part of the heat shielding member is made relatively large to effectively shield the radiant heat from the inner peripheral wall of the quartz crucible, and the temperature gradient in the axial direction of the silicon single crystal rod By pulling up the silicon single crystal rod at an optimum pulling rate so that the radial distribution is substantially uniform, a silicon single crystal rod composed of the perfect region [P] in which the aggregate of point defects does not exist can be manufactured. It has become.

However, even if the bulging portion of the heat shielding member is enlarged, the radial distribution of the temperature gradient in the axial direction of the silicon single crystal rod cannot be made substantially uniform unless the pulling speed is relatively slow. There has been a reality that it is not possible to improve the mass production effect of a silicon single crystal rod composed of a perfect region [P] in which no point defect agglomerates exist by increasing the speed of raising.
In addition, in the heat shielding member provided with the bulging part only at the lower part of the cylindrical part, when the oxide film is formed on the surface of the silicon wafer cut out from the pulled single crystal rod, the oxidation is performed regardless of the size of the bulging part. There is a problem that the pressure resistance characteristics of the film deteriorate. That is, if the bulge is small, the temperature gradient in the crystal axis direction near the solid-liquid interface between the silicon single crystal rod and the silicon melt and in the crystal axis direction near the single crystal outer peripheral surface is G ₁ (° C / ° C). mm) and G ₂ (° C./mm), the difference between the two temperature gradients (G ₂ −G ₁ ) becomes relatively large, so that COP and the like increase. For this reason, when an oxide film is formed on the surface of a silicon wafer cut out from the single crystal and the withstand voltage is evaluated, the oxide film withstand voltage characteristic deteriorates. Conversely, if the bulge is large, the radiant heat from the inner peripheral wall of the quartz crucible is blocked, so the temperature range of about 1400 to 1000 ° C. in the pulling direction of the single crystal to be pulled is relatively short. The point defects are not sufficiently diffused outward or sloped. As a result, there is a problem that the oxide film pressure resistance characteristic of the silicon wafer made from this single crystal is worse than when a heat shield member provided with a small bulge portion is used.

And as a heat shielding member that can improve the oxide film pressure resistance characteristics when such a silicon wafer is formed, a lower bulging portion is provided at the lower end of the cylindrical portion, and the lower side thereof is located above the lower bulging portion. There has been proposed a heat shielding member provided with an upper bulging portion with a predetermined distance from the bulging portion (see, for example, Patent Document 3). Thus, in the heat shielding member provided with the bulging portion with a predetermined interval above and below, the difference between both temperature gradients in the crystal axis direction in the vicinity of the single crystal center position near the solid-liquid interface and the single crystal outer peripheral surface (G ₂ -G ₁₎ relatively small to the well as to reduce the COP, etc. in the single crystal, the temperature of the vicinity of the outer peripheral surface of the pulled up single crystal is relatively long time until lowering to 1000 ° C. from 1400 ° C. In this case, outward diffusion and slope diffusion are promoted inside the single crystal, and as a result, the oxide film withstand voltage characteristic of a silicon wafer made from the single crystal can be improved.

On the other hand, there are various qualities required for silicon single crystal rods, and some may have agglomerates of point defects, and some do not require high oxide film pressure resistance characteristics of silicon wafers. For silicon single crystal rods with such quality requirements, the bulging part of the heat shielding member is downsized to reduce the amount of radiant heat from the quartz crucible, and the pulling speed is relatively high to increase the single crystal rod. A device for reducing the unit price of the crystal itself has been devised, and only when a high oxide film characteristic is required, a heat shielding member having bulged portions formed vertically is used. Therefore, conventionally, a swelled portion having a small heat shielding member, a bulging portion having a large heat shielding member, and a heat shielding member having a bulging portion formed in two stages are prepared, and the required quality silicon is prepared. The silicon single crystal rod is pulled up by using a heat shielding member suitable for the single crystal rod.
Japanese Patent Publication No.57-40119 Japanese Patent Application Laid-Open No. 11-1393 JP 2001-261494 A

However, in recent years, the quality required for silicon single crystal rods has diversified, and as a result, there has been a problem that a considerable number of heat shielding members must be provided that match the quality of each diversified silicon single crystal rod. It was.
The object of the present invention is to heat shield a silicon single crystal pulling apparatus that can relatively easily change the amount of heat radiation that is required by a small number of heat shielding members, when pulling silicon single crystal rods of various qualities. It is to provide a member.

In the invention according to claim 1, as shown in FIG. 5, the silicon single crystal rod 25 is pulled up 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. A cylindrical portion 37 provided at the apparatus, the lower end of which is located above the surface of the silicon melt 12 and which surrounds the outer peripheral surface of the silicon single crystal rod 25, and a lower portion of the cylindrical portion 37 swells in the in-cylinder direction. This is an improvement of the heat shielding member 36 including the bulging portion 41 provided.
As shown in detail in FIG. 1, the characteristic configuration is a ring-shaped heat insulating cover that is configured to be detachable from the cylindrical portion 37 and surrounds the outer peripheral surface of the silicon single crystal rod 25 while being inserted into the cylindrical portion 37. 51 and a support member 56 that is provided on the inner surface of the cylindrical portion 37 and supports the heat insulating cover 51 inserted into the cylindrical portion 37 above the bulging portion 41 with a predetermined gap therebetween. It is in.
In the heat shielding member of the silicon single crystal pulling apparatus described in claim 1, the heat insulating cover 51 of the heat shielding member 36 that supports the heat insulating cover 51 above the bulging portion 41 is detached from the cylindrical portion 37. The heat shielding member having the heat insulating cover 51 and the bulging portion 41 can be changed relatively easily to the heat shielding member 36 having only the bulging portion 41. When pulling up the silicon single crystal rod 25 having different required qualities, the type and number of heat shield members prepared are reduced compared to the conventional case where the whole is replaced with a heat shield member that meets the requirements. The pulling cost can be reduced.

The invention according to claim 2 is the invention according to claim 1, and as shown in FIGS. 3 and 4, the support member is a plurality of convex portions 56 provided on the inner surface of the cylindrical portion 37, and the ring A plurality of cutouts 51a corresponding to the projections 56 and passing through the projections 56 when the heat insulation cover 51 is inserted are formed on the outer peripheral surface of the heat insulation cover 51 in the shape of a plate, and the cutouts 51a are aligned with the projections 56 to be insulated. The heat insulating cover 51 is installed on the bulging portion 41 by inserting the cover 51 into the cylindrical portion 37, and the heat insulating cover 51 is inserted into the cylindrical portion 37 without matching the notch 51 a with the convex portion 56. 51 is configured to be supported above the bulging portion 41.
In the heat shielding member of the silicon single crystal pulling apparatus according to claim 2, the shielding amount of the radiant heat in the lower part of the cylindrical portion 37 can be remarkably improved by installing the heat insulating cover 51 on the bulging portion 41. . For this reason, it is not necessary to prepare a plurality of types of heat shielding members 36 with different sizes of the bulging portion 41, and when the silicon single crystal rods 25 having different qualities are pulled up, the heat insulating cover 51 is attached. Or reduce the cost of pulling up the single crystal by reducing the types and number of heat shielding members prepared compared to the conventional case where the whole is replaced by removing the radiant heat that meets the requirements. Can do.

  In the heat shielding member of the silicon single crystal pulling apparatus of the present invention, a ring-shaped heat insulating cover configured to be insertable / removable into the cylindrical portion and surrounding the outer peripheral surface of the silicon single crystal rod in a state of being inserted into the cylindrical portion, Since the heat insulating cover provided on the inner surface and supporting the heat insulating cover inserted into the cylindrical portion is provided above the bulging portion with a predetermined distance from the bulging portion, the heat insulating cover is supported above the bulging portion. By removing the heat insulating cover of the heat shielding member from the cylindrical portion, the heat shielding member having the heat insulating cover and the bulging portion can be relatively easily changed to a heat shielding member having only the bulging portion.

  Further, if the support member is a plurality of convex portions provided on the inner surface of the cylindrical portion, a plurality of cutouts corresponding to the convex portions on the outer peripheral surface of the ring-shaped heat insulating cover and capable of passing through the convex portions when the heat insulating cover is inserted. The heat insulation cover is installed on the bulge by inserting the heat insulation cover into the cylindrical portion with the notch aligned with the convex portion, and the heat insulation cover on the cylindrical portion without aligning the notch with the convex portion. By inserting, it can comprise so that a heat insulation cover may be supported above a bulging part. Then, by installing the heat insulating cover on the bulging part, it is possible to remarkably improve the shielding amount of the radiant heat at the lower part of the cylindrical part, and to prepare a plurality of types of heat shielding members having different bulging part sizes. In the past, the whole was replaced by installing or removing a heat insulating cover when pulling up a silicon single crystal rod with different required quality, without obtaining it, and obtaining a shielding amount of radiant heat meeting that requirement. It is possible to reduce the cost of pulling a single crystal by reducing the types and number of heat shielding members prepared in comparison.

Next, the best mode for carrying out the present invention will be described with reference to the drawings.
As shown in FIG. 5, 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.

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.

  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.

  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 36 surrounding the outer peripheral surface of the silicon single crystal rod 25 is provided. The heat shielding member 36 includes a cylindrical portion 37 that is formed in a cylindrical shape and shields radiant heat from the heater 18, and a flange portion 38 that is provided on the upper edge of the cylindrical portion 37 and projects outward in a substantially horizontal direction. By placing the flange portion 38 on the heat retaining cylinder 19, the heat shielding member 36 is fixed in the chamber 11 so that the lower edge of the cylindrical portion 37 is positioned a predetermined distance above the surface of the silicon melt 12. The The cylindrical portion 37 in this embodiment is a cylindrical body having the same diameter, and a bulging portion 41 that bulges in the direction of the cylinder is provided at the lower portion of the cylindrical portion 37.

As shown in detail in FIGS. 1 and 3, the bulging portion 41 includes a ring-shaped lower wall 42 whose outer periphery is connected to the lower edge of the cylindrical portion 37 and whose inner periphery reaches the vicinity of the outer peripheral surface of the silicon single crystal rod 25, An inner edge of the lower wall 42 and a ring-shaped upper wall 43 connecting the lower inner peripheral surface of the cylindrical portion 37 are formed. In this embodiment, the lower wall 42 and the upper wall 43 are made of thermally stable and high-purity graphite as in the case of the cylindrical portion 37 or graphite whose surface is coated with SiC. Materials such as (molybdenum) and W (tungsten) can also be used. The lower wall 42 is horizontal or formed so as to increase in diameter toward the upper side, and a ring-shaped heat storage member is formed inside the bulging portion 41 surrounded by the lower wall 42, the upper wall 43, and the lower portion of the cylindrical portion 37. 47 is provided. 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.

  The characteristic configuration of the present invention is that it includes a ring-shaped heat insulating cover 51 that is configured to be detachable from the cylindrical portion 37 and that surrounds the outer peripheral surface of the silicon single crystal rod 25 while being inserted into the cylindrical portion 37. . The heat insulating cover 51 in this embodiment includes a housing 52 and a heat insulating material 53 filled in the housing 52. The housing 52 is connected to the ring-shaped lower plate 52a overlapping the upper wall 43 forming the bulging portion 41, the inner plate 52b connected to the inner edge of the lower plate 52a, and the outer edge of the lower plate 52a. The outer plate 52c is constituted by an upper plate 52d having a ring shape that continuously connects the upper edge of the inner plate 52b and the upper edge of the outer plate 52c. The housing 52 is made of thermally stable and high-purity graphite or graphite having a surface coated with SiC, but a material such as Mo (molybdenum) having a low surface emissivity and being thermally stable can also be used. .

The heat insulating material 53 filled in the housing 52 is formed of a felt material of 0.05 to 0.50 g / cm ³ made of the same carbon fiber as the heat storage member 47 provided in the bulging portion 41. By using this carbon fiber as the heat insulating material 53, the heat conductivity of the heat insulating material 53 is limited to 5 W / (m · ° C.) or less. However, the heat insulating material 53 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.

  As shown in FIG. 1, on the inner surface of the cylindrical portion 37, a support member 56 that supports the heat insulating cover 51 inserted in the cylindrical portion 37 above the bulging portion 41 with a predetermined distance from the bulging portion 41. Provided. The support member in this embodiment is a plurality of convex portions 56 provided on the inner surface of the cylindrical portion 37. In this embodiment, as shown in FIGS. 2 and 4, four convex portions 56 are provided at the same height in the circumferential direction around the silicon single crystal rod 25 every 90 degrees, and FIG. As shown in FIG. 4, the four convex portions 56 are provided in two stages in the vertical direction, and the convex portions 56 are provided in a total of eight locations. On the other hand, as shown in FIGS. 2 and 4, the outer peripheral surface of the ring-shaped heat insulating cover 51 corresponds to the convex portion 56 which is a support member provided on the inner surface of the cylindrical portion 37 and is inserted when the heat insulating cover 51 is inserted. A plurality of cutouts 51a that can pass through the convex portion 56 are formed. Therefore, as shown in FIG. 4, by inserting the heat insulating cover 51 into the cylindrical portion 37 with the notch 51 a aligned with the convex portion 56, the heat insulating cover 51 can be lowered beyond the convex portion 56. As shown in FIG. 2, the heat insulating cover 51 can be installed on the bulging portion 41. As shown in FIG. 2, when the heat insulating cover 51 is inserted into the cylindrical portion 37 without matching the notch 51a to the convex portion 56, the heat insulating cover 51 is formed on the convex portion 56 as a support member as shown in FIG. It is configured to abut and be supported above the bulging portion 41.

  In the heat shielding member 36 of the silicon single crystal pulling apparatus configured in this way, as shown in FIG. 3, in the state where the heat insulating cover 51 is installed on the bulging portion 41, the silicon fusion member below the bulging portion 41 is melted. The periphery of the silicon single crystal rod 25 in the vicinity of the liquid 12 is positively heated by the high-temperature heater 18 and the silicon melt 12. On the other hand, the bulging portion 41 and the heat insulating cover 51 are positively heated by the high-temperature heater 18 and the silicon melt 12, and face both the bulging portion 41 and the heat insulating cover 51 installed in the bulging portion 41. The periphery of the silicon single crystal rod 25 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. A defect-free silicon single crystal rod 25 can be manufactured according to the model. On the other hand, the inside of the cylindrical portion 37 above the heat insulating cover 51 is shielded from the radiant heat from the heater 18 by the cylindrical portion 37, and is heated by both the bulging portion 41 and the heat insulating cover 51 installed in the bulging portion 41. The radiant heat from the silicon melt 12 is also blocked. Therefore, heat radiation from the silicon single crystal rod 25 located above the heat insulating cover 51 is promoted as compared with the lower portion of the silicon single crystal rod 25 described above.

  Conversely, when the heat insulating cover 51 is detached from the cylindrical portion 37 and the silicon single crystal rod 25 is pulled up from the silicon melt 12, the amount of heat radiation from the outer peripheral surface of the silicon single crystal rod 25 in the vicinity of the silicon melt 12 increases. The axial temperature gradient in the outer peripheral portion of the silicon single crystal rod 25 is higher than the axial temperature gradient in the center of the silicon single crystal rod 25. For this reason, the radial distribution of the temperature gradient in the axial direction of the silicon single crystal rod 25 cannot be made uniform, and the defect-free silicon single crystal rod 25 cannot be manufactured. However, since the temperature gradient in the axial direction becomes high, it is possible to increase the pulling speed of the silicon single crystal rod 25 as compared with the case of manufacturing the defect-free silicon single crystal rod 25.

On the other hand, when a relatively high pressure resistance characteristic is required for the oxide film formed on the surface of the silicon wafer cut out from the single crystal rod 25 pulled up, as shown in FIG. The heat insulating cover 51 is inserted into the cylindrical portion 37 without causing 51a to coincide with the convex portion 56, and the thermal insulating cover 51 is brought into contact with the convex portion 56 as a support member as shown in FIG. Support upward. As described above, in the heat shielding member 36 in which the heat insulating cover 51 is supported above the bulging portion 41, heat radiation in the silicon single crystal rod 25 located between the heat insulating cover 51 and the bulging portion 41 is suppressed at a certain rate. The difference in temperature gradient (G ₂ −G ₁ ) in the direction of the crystal axis in the vicinity of the single crystal center position near the solid-liquid interface and in the vicinity of the single crystal outer peripheral surface becomes relatively small, and COP in the single crystal rod 25 is reduced. Can be made. Further, the time until the temperature near the outer peripheral surface of the single crystal rod 25 pulled up drops from 1400 ° C. to 1000 ° C. is relatively long, and outward diffusion and slope diffusion are promoted inside the single crystal rod 25, As a result, the oxide film withstand voltage characteristic of the silicon wafer made from the single crystal rod 25 can be improved.

  Here, installation of the heat insulating cover 51 to the bulging portion 41 and removal of the heat insulating cover 51 from the cylindrical portion 37 in the heat shielding member 36 of the present invention are easier than when the entire heat shielding member 36 is replaced. Thus, it is not necessary to prepare a plurality of types of heat shielding members 36 having different bulging portions 41 in size. Further, the heat insulating cover 51 can be relatively easily supported above the bulging portion 41 by inserting the heat insulating cover 51 into the cylindrical portion 37 without aligning the notch 51 a with the convex portion 56. For this reason, it is not necessary to prepare the conventional heat shielding member in which the bulging portion is formed in two stages. In particular, in this embodiment, the four protrusions 56 are provided at the same height every 90 degrees, and the four protrusions 56 are provided in two stages up and down as shown in FIG. By supporting the cover 51 on the convex portion 56 at an arbitrary step, the interval between the heat insulating cover 51 and the bulging portion 41 can be changed based on the required pressure resistance characteristics.

  Accordingly, every time the silicon single crystal rods 25 having different required qualities are pulled up, the amount of radiant heat that meets the requirements is set on the bulging portion 41 of the heat insulating cover 51, or the heat insulating cover 51 is removed or the heat insulating cover 51 is removed. Is supported above the bulging portion 41, and the amount of radiant heat can be easily changed. And since the heat insulation cover 51 is provided with the housing 52 and the heat insulating material 53 with which the housing 52 was filled, it is possible to change easily the amount of interruption | blocking of the radiant heat of the heat insulation cover 51 with the kind or filling amount of the heat insulating material 53. Thus, it is possible to obtain the heat insulating cover 51 having a blocking amount to be obtained relatively easily.

In the above-described embodiment, the example in which the four convex portions 56 that are the support members are provided at the same height every 90 degrees has been described. However, the convex portions that are the support members provided at the same height. The number 56 is not limited to four, and may be three, five, six, or eight as long as the heat insulating cover 51 can be supported.
In the above-described embodiment, the example in which the four convex portions 56 provided at the same height are provided in two stages in the vertical direction has been described. However, the convex portions 56 that are a plurality of support members are two in the vertical direction. It may not be a stage, and may be one stage, three stages, or four stages.

It is the A section expanded sectional view of Drawing 5 showing the composition of the heat shielding member of the embodiment of the present invention. It is the BB sectional view taken on the line of FIG. It is an expanded sectional view corresponding to FIG. 1 with which the heat insulation cover was installed in the bulging part. It is CC sectional view taken on the line of FIG. It is a section lineblock diagram of a pulling device which has the heat shielding member.

Explanation of symbols

12 Silicon melt 13 Quartz crucible 18 Heater 25 Silicon single crystal rod 36 Heat shield member 37 Cylindrical part 41 Swelling part 51 Thermal insulation cover 51a Notch 56 Convex part (support 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). A cylindrical portion (37) 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), and a lower portion of the cylindrical portion (37) In the heat shielding member (36) provided with a bulging portion (41) provided to bulge in the direction in the cylinder,
A ring-shaped heat insulating cover (51) configured to be detachably inserted into the cylindrical portion (37) and surrounding the outer peripheral surface of the silicon single crystal rod (25) in a state of being inserted into the cylindrical portion (37);
The heat insulating cover (51) provided on the inner surface of the cylindrical portion (37) and inserted into the cylindrical portion (37) is spaced apart from the bulging portion (41) by a predetermined distance from the bulging portion (41). A heat shielding member for a silicon single crystal pulling apparatus, comprising: a supporting member (56) supported upward. The support member is a plurality of convex portions (56) provided on the inner surface of the cylindrical portion (37),
A plurality of cutouts (51a) corresponding to the projections (56) and passing through the projections (56) when the insulation cover (51) is inserted are formed on the outer peripheral surface of the ring-shaped insulation cover (51). And
By inserting the heat insulating cover (51) into the cylindrical part (37) with the notch (51a) aligned with the convex part (56), the heat insulating cover (51) is placed on the bulging part (41). Install
By inserting the heat insulating cover (51) into the cylindrical portion (37) without causing the notch (51a) to coincide with the convex portion (56), the heat insulating cover (51) is inserted into the bulging portion (41). The heat shielding member of the silicon single crystal pulling apparatus according to claim 1, wherein the heat shielding member is configured to support the upper portion of the silicon single crystal pulling apparatus.

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