Heat shielding member and its part set, and single crystal manufacturing apparatus and single crystal manufacturing method using the heat shielding member

Abstract

To provide a heat shield member capable of growing single crystals having different crystal diameters using the same CZ pulling furnace, and an apparatus and method for manufacturing a single crystal using the same.SOLUTION: A heat shield member 20 used for pulling a single crystal by the CZ method and surrounding the single crystal pulled from a melt in a crucible includes an approximately cylindrical insulating member 30 and a wall member 40 covering the exposed surface of the insulating member 30. The wall member 40 includes: an outer wall part 41 covering at least the outer peripheral surface of the insulating member 30; an inner wall part 42 covering the inner peripheral surface of the insulating member 30; and a bottom wall part 43 covering the lower end surface of the insulating member 30. The insulating member 30 includes an approximately cylindrical first heat insulation part 31 and an approximately cylindrical second heat insulation part 32 provided in the inside of the first heat insulation part 31, and the second heat insulation part 32 is freely attachably / detachably constituted of the first heat insulation part 31.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a heat shielding member and a part set thereof used in pulling a single crystal by the Czochralski method (CZ method), and also to a single crystal manufacturing apparatus and a single crystal manufacturing method using such a heat shielding member. [Background technology]

[0002] Most of the silicon single crystals used as substrate materials for semiconductor devices are produced by the CZ method. In the CZ method, a seed crystal is immersed in molten silicon contained in a quartz crucible, and the seed crystal and the quartz crucible are rotated while the seed crystal is gradually pulled up, causing a large single crystal to grow at the bottom end of the seed crystal. The CZ method makes it possible to produce high-quality silicon single crystal ingots with a high yield.

[0003] In order to improve the crystal quality of silicon single crystals, the CZ method uses a heat shielding member that surrounds the silicon single crystal pulled up from the silicon melt to shield it from radiant heat from a heater. Regarding the heat shielding member, for example, Patent Document 1 describes a method of preventing concentration of thermal stress on a notch by dividing a disk-shaped bottom plate of a heat shield into two parts. Patent Document 2 describes a heat shielding member in which only the bottom of a bulge can be replaced.

[0004] Patent Document 3 describes changing the distance of multiple radially movable heat radiators from the peripheral surface of a silicon single crystal rod in order to pull up silicon single crystal rods with different straight body diameters without replacing the heat shielding member. When forming the shoulder of the silicon single crystal rod, the multiple heat radiators are moved to a position away from the shoulder, and when forming the straight body of the silicon single crystal rod, the multiple heat radiators are moved to the vicinity of the straight body.

[0005] Silicon single crystals are used not only as substrate materials for semiconductor devices, but also as electrode materials for plasma etching equipment, for example. Patent Document 4 describes the use of silicon single crystals as electrode plates for plasma etching equipment. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2004-323322 A [Patent Document 2] JP 2004-352581 A [Patent Document 3] JP 2000-7488 A [Patent Document 4] JP 2003-51491 A Summary of the Invention [Problem to be solved by the invention]

[0007] Unlike silicon single crystals for semiconductors, silicon single crystals for electrode materials do not have standardized crystal diameters, and the required crystal diameter varies depending on the equipment design. For this reason, in the manufacture of silicon single crystals for electrode materials, it is necessary to efficiently produce silicon single crystals with different diameters of the straight body (hereinafter simply referred to as crystal diameter) according to the order volume. In order to meet such requirements, traditionally, dedicated heat shielding members were prepared for each crystal diameter to be pulled. However, preparing dedicated heat shielding members for each crystal diameter increases costs due to the increase in the number of parts required, and also poses the problem of securing storage space.

[0008] Therefore, an object of the present invention is to provide a heat shielding member and a component set thereof that enable efficient pulling of single crystals with different crystal diameters using the same CZ pulling furnace, as well as a single crystal manufacturing apparatus and a single crystal manufacturing method using the heat shielding member. [Means for solving the problem]

[0009] In order to solve the above problems, the heat-shielding member of the present invention is used in pulling a single crystal by the CZ method, and is a member that surrounds the single crystal pulled up from a melt in a crucible, and comprises an approximately cylindrical insulating member and a wall member covering the exposed surface of the insulating member, the wall member comprising an outer wall portion covering at least the outer peripheral surface of the insulating member, an inner wall portion covering the inner peripheral surface of the insulating member, and a bottom wall portion covering the lower end surface of the insulating member, the insulating member including an approximately cylindrical first insulating portion and an approximately cylindrical second insulating portion provided inside the first insulating portion, and the second insulating portion is configured to be freely attached and detached from the first insulating portion.

[0010] According to the present invention, when pulling multiple types of single crystals with different crystal diameters, the first insulating part of the insulating member and the outer wall part of the wall member are common parts, and the opening size can be changed by omitting or replacing the parts inside the first insulating part, such as the second insulating part and the inner wall part. Therefore, multiple types of single crystals with different crystal diameters can be efficiently pulled using the same CZ pulling furnace.

[0011] In the present invention, it is preferable that the outer peripheral surface of the first insulating part is covered by the outer wall part, the inner peripheral surface of the second insulating part is covered by the inner wall part, and the outer peripheral surface of the second insulating part is in close contact with the inner peripheral surface of the first insulating part. This allows the first and second insulating parts to be handled as a single insulating member, and by combining the first and second insulating parts, a heat shielding member suitable for pulling a small-diameter single crystal can be provided. Also, by removing the second insulating part, a heat shielding member suitable for pulling a large-diameter single crystal can be provided.

[0012] In the present invention, it is preferable that the bottom wall is detachably attached to the outer wall, the inner wall is detachably attached to the bottom wall and the outer wall, and the second bottom wall is detachably attached to the first bottom wall, thereby making it possible to accommodate both small-diameter and large-diameter single crystals.

[0013] In the present invention, it is preferable that the upper surface of the inner peripheral end of the bottom wall portion connected to the lower end of the inner wall portion is provided with a tapered surface inclined toward the outside in the radial direction, and the lower end of the inner wall portion abuts against the tapered surface. This makes it possible to increase the adhesion between the inner wall portion and the bottom wall portion at the connection position, and to maintain the sealing state of the heat insulating member by the wall member. Therefore, even if the heat insulating member deteriorates and turns into powder, it is possible to prevent deterioration of the yield of single crystals due to the fine powder of the heat insulating member leaking outward.

[0014] In the present invention, it is preferable that the lower end of the outer wall portion connected to the outer peripheral end of the bottom wall portion has a tapered surface inclined toward the outside in the radial direction, and the outer peripheral end of the bottom wall portion abuts against the tapered surface. This makes it possible to increase the adhesion between the bottom wall portion and the outer wall portion at the connection position, and to maintain the sealing state of the heat insulating member by the wall member. Therefore, even if the heat insulating member deteriorates and turns into powder, it is possible to prevent deterioration of the yield of single crystals due to the fine powder of the heat insulating member leaking outward.

[0015] In the present invention, it is preferable that a protrusion is provided at the lower end of the outer wall portion, and a hook portion that engages with the protrusion is provided at the outer peripheral end of the bottom wall portion. In this case, too, it is possible to improve the adhesion between the bottom wall portion and the outer wall portion at the connection position, and to maintain the sealing state of the heat insulating member by the wall member.

[0016] In the present invention, the difference between the opening diameter of the heat shielding member when the first insulation part is used alone and the opening diameter of the heat shielding member when the first insulation part and the second insulation part are used in combination is preferably 50 mm (about 2 inches) or more. This makes it possible to efficiently pull a plurality of types of single crystals with different crystal diameters using the same CZ pulling furnace.

[0017] In the present invention, the inner wall portion is preferably a substantially cylindrical first inner wall portion covering the inner circumferential surface of the first heat insulating portion or a substantially cylindrical second inner wall portion covering the inner circumferential surface of the second heat insulating portion. By using the first inner wall portion in combination with the first heat insulating portion, a heat shielding member having a large opening size can be realized. Also, by combining the second inner wall portion with the first and second heat insulating portions, a heat shielding member having a small opening size can be realized.

[0018] In the present invention, the difference between the opening diameter of the first inner wall portion and the opening diameter of the second inner wall portion is preferably 50 mm or more, which makes it possible to efficiently pull two types of single crystals having a diameter difference of 50 mm or more.

[0019] In the heat-shielding member according to the present invention, when a first single crystal is pulled, the second heat-insulating portion is omitted and the first heat-insulating portion is used alone, and the bottom wall portion is omitted and the first inner wall portion is used in combination with the outer wall portion, and when a second single crystal having a smaller diameter than the first single crystal is pulled, the second heat-insulating portion is used in combination with the first heat-insulating portion, and the second inner wall portion and the bottom wall portion are used in combination with the outer wall portion. In this way, the heat-shielding member according to the present invention can be applied to both of the CZ pulling processes of first and second single crystals having different crystal diameters.

[0020] The bottom wall portion is preferably a substantially annular first bottom wall portion covering a lower end surface of the first heat insulating portion or a substantially annular second bottom wall portion covering the lower end surfaces of the first and second heat insulating portions. By using the first bottom wall portion in combination with the first heat insulating portion and the first inner wall portion, a heat shielding member having a large opening size can be formed. Also, by using the second bottom wall portion in combination with the first and second heat insulating portions and the second inner wall portion, a heat shielding member having a small opening size can be formed.

[0021] In the heat-shielding member according to the present invention, when a first single crystal is pulled, it is preferable that the second heat-insulating part is omitted and the first heat-insulating part is used alone, and the first inner wall part and the first bottom wall part are used in combination with the outer wall part, and when a second single crystal having a smaller diameter than the first single crystal is pulled, it is preferable that the second heat-insulating part is used in combination with the first heat-insulating part, and the second inner wall part and the second bottom wall part are used in combination with the outer wall part. In this way, the heat-shielding member according to the present invention can be applied to both of the CZ pulling processes of the first and second single crystals having different crystal diameters.

[0022] The present invention also relates to a parts set for a heat-shielding member used in pulling a single crystal by the CZ method, and surrounding the single crystal pulled up from a melt in a crucible, the parts set comprising: a first insulating section having a substantially cylindrical shape; a second insulating section having a substantially cylindrical shape that is removably attached inside the first insulating section; an outer wall section covering an outer peripheral surface of the first insulating section; a first inner wall section covering an inner peripheral surface of the first insulating section; and a second inner wall section covering an inner peripheral surface of the second insulating section, the first heat-shielding member being composed of the first insulating section, the outer wall section, and the first inner wall section, and the second heat-shielding member having an opening diameter smaller than that of the first heat-shielding member being composed of the first insulating section, the second insulating section, the outer wall section, and the second inner wall section.

[0023] According to the present invention, the opening diameter of the heat shielding member can be changed by adding or replacing some of the components of the heat shielding member, making it possible to accommodate the pulling of a variety of single crystals with different crystal diameters.

[0024] Furthermore, it is preferable that the parts set of the heat-shielding member according to the present invention further comprises a bottom wall portion covering at least the lower end surface of the second heat insulating portion, and the second heat-shielding member further comprises the bottom wall portion. Furthermore, the parts set of the heat-shielding member according to the present invention may further comprise a first bottom wall portion covering the lower end surface of the first heat insulating portion and a second bottom wall portion covering the lower end surfaces of the first and second heat insulating portions, the first heat-shielding member further comprises the first bottom wall portion, and the second heat-shielding member further comprises the second bottom wall portion. In this way, by adding or replacing bottom wall portions, it is possible to provide a heat-shielding member that can accommodate the pulling of a plurality of single crystals having different crystal diameters.

[0025] In the present invention, the difference between the opening diameter of the first inner wall portion and the opening diameter of the second inner wall portion is preferably 50 mm or more, which makes it possible to efficiently pull a plurality of types of single crystals having different crystal diameters using the same CZ pulling furnace.

[0026] The single crystal manufacturing apparatus according to the present invention is characterized by comprising a chamber, a crucible for supporting the melt in the chamber, a heater for heating the melt, a crucible drive mechanism for rotating and raising and lowering the crucible, a crystal pulling mechanism for pulling the single crystal from the melt, and the heat shielding member according to the present invention described above, which is installed above the melt and surrounds the single crystal pulled from the melt to shield it from radiant heat from the heater. According to the present invention, the opening size can be changed by omitting or changing some parts. Therefore, multiple types of single crystals with different crystal diameters can be efficiently pulled using the same CZ pulling furnace.

[0027] Furthermore, the method for producing a single crystal according to the present invention is characterized in that in the CZ method in which a single crystal is pulled from the melt in a crucible, the single crystal pulled from the melt is surrounded by the heat shielding member according to the present invention described above. According to the present invention, the opening size can be changed by omitting or modifying some parts, and multiple types of single crystals with different crystal diameters can be pulled efficiently.

[0028] In the method for producing a single crystal according to the present invention, it is preferable to use the heat shielding member formed by using the first heat insulating part alone to pull a first single crystal having a first crystal diameter, and to use the heat shielding member formed by combining the first heat insulating part and the second heat insulating part to pull a second single crystal having a second crystal diameter smaller than the first crystal diameter. This makes it possible to change the opening size by omitting or changing some parts, and efficiently pull two types of single crystals with different crystal diameters.

[0029] In the present invention, the difference between the first crystal diameter and the second crystal diameter is preferably 50 mm (about 2 inches) or more. This makes it possible to efficiently pull two types of single crystals having different crystal diameters using the same CZ pulling furnace. Effect of the Invention

[0030] According to the present invention, it is possible to provide a heat shielding member and a component set thereof that enable efficient pulling of single crystals with different crystal diameters using the same CZ pulling furnace, as well as a single crystal manufacturing apparatus and a single crystal manufacturing method that use the heat shielding member. [Brief description of the drawings]

[0031] [Figure 1] FIG. 1 is a schematic cross-sectional side view showing the configuration of a single crystal manufacturing apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic cross-sectional view showing the configuration of the heat shielding member according to the first embodiment of the present invention in a completed state. [Diagram 3] FIG. 3 is a schematic cross-sectional view showing the configuration of the heat shielding member according to the first embodiment of the present invention in an exploded state. [Figure 4] FIG. 4 is a schematic cross-sectional view showing the structure of a completed heat shielding member according to the second embodiment of the present invention. [Diagram 5] FIG. 5 is a schematic cross-sectional view showing the configuration of a heat shielding member according to a second embodiment of the present invention in an exploded state. [Figure 6]FIG. 6 is a schematic cross-sectional view showing the structure of a completed heat shielding member according to the third embodiment of the present invention. [Figure 7] FIG. 7 is a schematic cross-sectional view showing the structure of a completed heat shielding member according to the fourth embodiment of the present invention. [Figure 8] FIG. 8 is a schematic cross-sectional view showing the configuration of a heat shielding member according to the fourth embodiment of the present invention in an exploded state. [Figure 9] FIG. 9 is a schematic cross-sectional view showing the structure of a completed heat shielding member according to the fifth embodiment of the present invention. [Figure 10] FIG. 10 is a schematic cross-sectional view showing the configuration of a heat shielding member according to the fifth embodiment of the present invention in an exploded state. [Figure 11] FIG. 11 is a schematic cross-sectional view showing the structure of a heat shielding member in a completed state according to the sixth embodiment of the present invention. [Figure 12] FIG. 12 is a schematic cross-sectional view showing the configuration of a heat shielding member according to the sixth embodiment of the present invention in an exploded state. [Figure 13] FIG. 13 is a schematic cross-sectional view showing the structure of a heat shielding member in a completed state according to the seventh embodiment of the present invention. [Figure 14] FIG. 14 is a schematic cross-sectional view showing the configuration of a heat shielding member according to the seventh embodiment of the present invention in an exploded state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0033] FIG. 1 is a schematic cross-sectional side view showing the configuration of a single crystal manufacturing apparatus according to an embodiment of the present invention.

[0034] As shown in FIG. 1, the single crystal manufacturing apparatus 1 includes a water-cooled chamber 10, a quartz crucible 11 for holding a silicon melt 2 within the chamber 10, a graphite crucible 12 for holding the quartz crucible 11, a rotating shaft 13 for supporting the graphite crucible 12, a shaft driving mechanism 14 for rotating and raising and lowering the quartz crucible 11 via the rotating shaft 13 and the graphite crucible 12, a heater 15 arranged around the graphite crucible 12, an insulating material 16 arranged outside the heater 15 and along the inner surface of the chamber 10, a wire 17 for pulling a single crystal arranged above the quartz crucible 11 and coaxially with the rotating shaft 13, a wire winding mechanism 18 arranged above the chamber 10, and a heat shielding member 20 arranged above the quartz crucible 11.

[0035] The chamber 10 is composed of a main chamber 10a and a long and thin cylindrical pull chamber 10b connected to the upper opening of the main chamber 10a, and the quartz crucible 11, the graphite crucible 12, the heater 15, and the heat shielding member 20 are provided in the main chamber 10a. The pull chamber 10b is provided with a gas inlet 10c for introducing an inert gas (purge gas) such as argon gas and a dopant gas into the chamber 10, and a gas outlet 10d for discharging the atmospheric gas in the chamber 10 is provided at the bottom of the main chamber 10a. In addition, a sight window (not shown) is provided at the top of the main chamber 10a, and the growth status of the silicon single crystal 3 can be observed through the sight window.

[0036] The quartz crucible 11 is a container made of silica glass having a substantially cylindrical side wall and a curved bottom. The graphite crucible 12 supports the quartz crucible 11 by being in close contact with the outer surface of the quartz crucible 11 in order to maintain the shape of the quartz crucible 11 softened by heating. The quartz crucible 11 and the graphite crucible 12 form a double-structure crucible that supports the silicon melt in the chamber 10.

[0037] The graphite crucible 12 is fixed to the upper end of a rotating shaft 13, and the lower end of the rotating shaft 13 passes through the bottom of the chamber 10 and is connected to a shaft driving mechanism 14 provided outside the chamber 10. The rotating shaft 13 and the shaft driving mechanism 14 constitute a crucible driving mechanism that drives the quartz crucible 11 to rotate and raise and lower.

[0038] The heater 15 is used to heat the silicon raw material filled in the quartz crucible 11 to generate the silicon melt 2 and to maintain the molten state of the silicon melt 2. The heater 15 is a resistance heating heater made of carbon, and is provided so as to surround the quartz crucible 11 in the graphite crucible 12. A heat insulating material 16 is provided on the outside of the heater 15 so as to surround the heater 15, thereby improving the heat retention inside the chamber 10.

[0039] Above the quartz crucible 11, there is provided a wire 17 which is a pulling shaft for the silicon single crystal 3, and a wire winding mechanism 18 which winds up the wire 17. The wire winding mechanism 18, together with the wire 17, constitutes a crystal pulling mechanism which pulls up the silicon single crystal 3 while rotating it. The wire winding mechanism 18 is disposed above the pull chamber 10b, and the wire 17 extends downward from the wire winding mechanism 18 through the pull chamber 10b, with the tip of the wire 17 reaching the internal space of the main chamber 10a. FIG. 1 shows a state in which the silicon single crystal 3 is suspended from the wire 17 during growth. When the silicon single crystal 3 is pulled up, the wire 17 is gradually pulled up while the quartz crucible 11 and the silicon single crystal 3 are each rotated, thereby growing the silicon single crystal 3.

[0040] The heat shielding member 20 is provided to suppress temperature fluctuations in the silicon melt 2 to form an appropriate hot zone in the vicinity of the crystal growth interface, and to prevent heating of the silicon single crystal 3 due to radiant heat from the heater 15 and the quartz crucible 11. The heat shielding member 20 is a substantially cylindrical member made of graphite, and is provided so as to cover the region above the silicon melt 2 excluding the pulling path for the silicon single crystal 3.

[0041] The diameter of the opening 20a at the lower end of the heat shielding member 20 is larger than the diameter of the silicon single crystal 3, thereby ensuring a pulling path for the silicon single crystal 3. In addition, the outer diameter of the lower end of the heat shielding member 20 is smaller than the aperture of the quartz crucible 11, and the lower end of the heat shielding member 20 is located inside the quartz crucible 11. Therefore, even if the upper end of the rim of the quartz crucible 11 is raised above the lower end of the heat shielding member 20, the heat shielding member 20 will not interfere with the quartz crucible 11.

[0042] Although the amount of melt in the quartz crucible 11 decreases as the silicon single crystal 3 grows, by raising the quartz crucible 11 so that the gap between the melt surface and the heat shielding member 20 becomes constant, it is possible to suppress temperature fluctuations in the silicon melt 2 and to control the amount of dopant evaporation from the silicon melt 2 by keeping constant the flow rate of the gas flowing near the melt surface. Therefore, it is possible to improve the stability of the crystal defect distribution, oxygen concentration distribution, resistivity distribution, etc. in the pulling axial direction of the silicon single crystal 3.

[0043] In the manufacture of silicon single crystal 3, first, polycrystalline silicon raw material is put into quartz crucible 11, and the raw material in quartz crucible 11 is heated and melted by heater 15 to generate silicon melt 2. Next, a seed crystal attached to the lower end of wire 17 is lowered to make it contact with silicon melt 2. Thereafter, the seed crystal is gradually pulled up while maintaining contact with silicon melt 2 to grow silicon single crystal 3. In the crystal pulling process, the diameter is gradually increased to form a shoulder portion, and then the diameter is kept constant to form a straight body portion. After the straight body portion of the desired length is formed, the diameter is gradually reduced to separate it from silicon melt 2. Through the above steps, a silicon single crystal ingot is completed.

[0044] 2 and 3 are schematic cross-sectional views showing the configuration of a heat shielding member according to a first embodiment of the present invention, with FIG. 2 being a completed view and FIG. 3 being an exploded view.

[0045] 2 and 3, the heat shielding member 20 according to this embodiment includes a substantially cylindrical heat insulating member 30 and a wall member 40 that covers the exposed surface of the heat insulating member 30. A felt material made of carbon fiber can be used as the heat insulating member 30. Alternatively, alumina or the like can be used as the heat insulating member. The material of the wall member 40 can be thermally stable and high-purity graphite or graphite with a SiC coating on the surface. Alternatively, thermally stable Mo (molybdenum) or W (tungsten) can be used as the wall member.

[0046] The heat insulating member 30 is composed of a first heat insulating section 31 having a substantially cylindrical shape. The outer peripheral surface 31a of the first heat insulating section 31 is a vertical surface and constitutes the outer peripheral surface 30a of the heat insulating member 30. The inner peripheral surface 31b of the first heat insulating section 31 constitutes a downwardly tapered surface. The lower end surface 31c of the first heat insulating section 31 is a horizontal surface, and furthermore, a chamfered tapered surface is provided at the corner portion on the outer peripheral side. The outer peripheral surface 31a of the first heat insulating section 31 may constitute a downwardly tapered surface.

[0047] The wall member 40 includes an outer wall portion 41 covering the outer peripheral region of the outer peripheral surface 30a and the lower end surface 30c of the insulation member 30, an inner wall portion 42 covering the inner peripheral surface 30b of the insulation member 30, and a bottom wall portion 43 covering the inner peripheral region of the lower end surface 30c of the insulation member 30.

[0048] The outer wall portion 41 is a substantially cylindrical member, and covers the outer peripheral surface 31a and the outer peripheral region of the lower end surface 31c of the first insulating portion 31. The inner peripheral surface of the outer wall portion 41 is in close contact with the outer peripheral surface 31a of the first insulating portion 31. The first insulating portion 31 is stored in the outer wall portion 41 by inserting the first insulating portion 31 from the upper opening of the outer wall portion 41 to the inside. The first insulating portion 21 can be easily removed from the outer wall portion 41 by lifting it upward. In this embodiment, the cylindrical shape of the outer wall portion 41 has a constant diameter from the upper end to the position of the downward tapered portion, but may be a substantially inverted truncated cone shape in which the diameter gradually decreases.

[0049] The inner wall portion 42 is a substantially cylindrical member, and is installed inside the substantially cylindrical outer wall portion 41, and covers the inner circumferential surface 31b of the first heat insulating portion 31. The first inner wall portion 42X having a shape that fits the inner circumferential surface 31b of the first heat insulating portion 31 is used as the inner wall portion 42, and the outer circumferential surface of the first inner wall portion 42X is in close contact with the inner circumferential surface 31b of the first heat insulating portion 31. The upper end portion of the first inner wall portion 42X abuts against the inner circumferential surface near the upper end portion of the outer wall portion 41, and covers the upper end surface 31d of the first heat insulating portion 31 that constitutes the upper end surface 30d of the heat insulating member 30. The lower end portion of the first inner wall portion 42X abuts against the upper surface near the inner circumferential end portion of the bottom wall portion 43. The first inner wall portion 42X has a flat shape that is inclined obliquely from the upper end portion to the lower end portion, but may have a step on the way.

[0050] Usually, the opening diameter of the heat shielding member 20 becomes smaller toward the bottom, and is smallest near the bottom end. The opening shape of the heat shielding member that has a large effect on pulling of the single crystal is the opening diameter near the bottom end close to the solid-liquid interface, so the opening diameter of the inner wall portion 42 refers to the minimum value of the opening diameter near the bottom end. The same applies to the opening diameters of the heat shielding member 20 and other parts.

[0051] The bottom wall portion 43 is a substantially annular member, and is disposed inside the substantially cylindrical outer wall portion 41 to cover the inner peripheral region of the lower end surface 31c of the first heat insulating portion 31. As the bottom wall portion 43, a large-diameter first bottom wall portion 43X that matches the size of the first heat insulating portion 32X is used. It is preferable that the upper surface of the first bottom wall portion 43X is in close contact with the lower end surface 31c of the first heat insulating portion 31. The first bottom wall portion 43X is placed on the upper surface of the inner peripheral end portion (lower end portion) of the outer wall portion 41, and forms a circular annular bottom plate. A step is provided in the first bottom wall portion 43X, and the step is fitted into the inner peripheral end portion of the outer wall portion 41, thereby positioning and fixing the first bottom wall portion 43X to the center of the heat shielding member 20.

[0052] In the installed state of the first inner wall portion 42X, it is preferable that the lower end portion of the first inner wall portion 42X is in close contact with the inner peripheral end portion of the first bottom wall portion 43X. In order to ensure such a close contact state, it is preferable that the lower end surface of the first inner wall portion 42X is formed with a tapered surface 42t that is inclined obliquely upward toward the center in the radial direction in the installed state. Similarly, it is preferable that the upper surface of the inner peripheral end portion of the first bottom wall portion 43X is also formed with a tapered surface 43t having approximately the same inclination angle as the lower end surface of the first inner wall portion 42X. In this way, the tapered surface 42t of the lower end portion of the first inner wall portion 42X is engaged with the tapered surface 43t of the inner peripheral end portion of the first bottom wall portion 43X in surface contact with each other, thereby sealing the storage space of the heat insulating member 30.

[0053] A similar tapered surface is preferably provided at the connection position between the outer wall portion 41 and the first bottom wall portion 43X. That is, a tapered surface 41u is formed on the upper surface of the inner peripheral end portion of the outer wall portion 41, and a tapered surface 43u having approximately the same inclination angle as the tapered surface 41u is formed on the bottom surface of the outer peripheral end portion of the first bottom wall portion 43X. Therefore, the connection between the two can be strengthened to seal the storage space of the heat insulating member 30.

[0054] Since the heat insulating member 30 gradually deteriorates and turns into powder, if the heat insulating member 30 is not sealed properly by the wall member 40, the powder of the heat insulating member 30 will leak out and adversely affect the yield of the single crystal. However, if the joints between the multiple parts that make up the wall member 40 are tightly sealed, the leakage of the powder can be prevented.

[0055] 3, the heat shielding member 20 according to this embodiment is completed by installing each part in a predetermined order inside the outer wall portion 41. Each part simply needs to be housed inside the outer wall portion 41, and no special fixing means are required. Therefore, each part can be extremely easily removed or replaced.

[0056] As described above, the heat insulating member 30 according to this embodiment is composed only of the first heat insulating section 31, and the wall member 40 uses the first inner wall section 42X and the first bottom wall section 43X corresponding to the first heat insulating section 31, thereby forming a heat shielding member 20 having a relatively large opening size. When it is desired to form a heat shielding member 20 having a relatively small opening size, parts must be added or changed.

[0057] 4 and 5 are schematic cross-sectional views showing the configuration of a heat shielding member according to a second embodiment of the present invention, with FIG. 4 being a completed view and FIG. 5 being an exploded view.

[0058] As shown in Figs. 4 and 5, the heat shielding member 20 according to this embodiment is a modified example of the first embodiment shown in Figs. 2 and 3, and the heat insulating member 30 is composed of a combination of a first heat insulating section 31 and a second heat insulating section 32. The first heat insulating section 31 is the same as that used in the first embodiment. The second heat insulating section 32 is a substantially cylindrical member provided on the inner periphery side of the first heat insulating section 31, and is configured to be detachable from the first heat insulating section 31. In other words, the heat insulating member 30 according to this embodiment is obtained by adding the second heat insulating section 32 to the first heat insulating section 31, which is a common part with the first embodiment.

[0059] The outer peripheral surface 32a of the second insulating section 32 is a tapered surface that fits the inner peripheral surface 31b of the first insulating section 31 and is in close contact with the inner peripheral surface 31b. The inner peripheral surface 32b of the second insulating section 32 is a tapered surface with an inclination angle close to the outer peripheral surface 32a and constitutes the inner peripheral surface 30b of the insulating member 30. When the second insulating section 32 is inserted from the upper opening of the first insulating section 31 to the inside, the outer peripheral surface 32a of the second insulating section 32 is in close contact with the inner peripheral surface 31b of the first insulating section 31 and the two are integrated. The second insulating section 32 can be easily removed from the first insulating section 31 by lifting it upward.

[0060] In this embodiment, the second insulation section 32 is a relatively large member extending over a wide area from the upper end to the lower end of the first insulation section 31, but it may also be a relatively small member provided only on the lower end of the first insulation section 31.

[0061] The wall member 40 includes an outer wall portion 41 that covers the outer peripheral area of ​​the outer peripheral surface 30a and the bottom end surface 30c of the heat insulating member 30, an inner wall portion 42 that covers the inner peripheral surface 30b of the heat insulating member 30, and a bottom wall portion 43 that covers the inner peripheral area of ​​the bottom end surface 30c of the heat insulating member 30. Here, the outer wall portion 41 is the same as that used in the first embodiment, and, like the first heat insulating portion 31, is a component common to the first and second embodiments.

[0062] As the inner wall portion 42, a second inner wall portion 42Y having a shape that fits the inner circumferential surface 32b of the second heat insulating portion 32 is used, and as the bottom wall portion 43, a second bottom wall portion 43Y for a small diameter is used to match the use of the second heat insulating portion 32. Therefore, the shape of the second inner wall portion 42Y is slightly different from that of the first inner wall portion 42X, and the shape of the second bottom wall portion 43Y is slightly different from that of the first bottom wall portion 43X.

[0063] The outer peripheral surface of the second inner wall portion 42Y is in close contact with the inner peripheral surface 32b of the second heat insulating portion 32, and the upper surface of the second bottom wall portion 43Y is in close contact with at least the lower end surface 32c of the second heat insulating portion 32. The upper end portion of the second inner wall portion 42Y abuts against the inner peripheral surface near the upper end portion of the outer wall portion 41, and covers the upper end surface 31d of the first heat insulating portion 31 and the upper end surface 32d of the second heat insulating portion 32, which constitute the upper end surface 30d of the heat insulating member 30. The lower end portion of the second inner wall portion 42Y abuts against the upper surface near the inner peripheral end portion of the bottom wall portion 43. The inner wall portion 42 has a flat shape that is inclined obliquely from the upper end portion to the lower end portion, but may have a step along the way.

[0064] 2 and 3, when the first insulating section 31 is used alone, the opening size of the heat insulating member 20 can be increased, and it is preferable for use in pulling a silicon single crystal with a large crystal diameter. On the other hand, when the first insulating section 31 and the second insulating section 32 are combined as in this embodiment, the opening size (diameter of the opening 20a) of the heat insulating member 20 can be reduced, and it is preferable for use in pulling a silicon single crystal with a small crystal diameter.

[0065] In this way, two types of inner wall portions 42 of the heat-shielding member 20 are prepared: a first inner wall portion 42X that matches the shape of the inner circumferential surface 31b of the first insulating portion 31, and a second inner wall portion 42Y that matches the shape of the inner circumferential surface 32b of the second insulating portion 32, and one of them is selectively used according to the usage state of the second insulating portion 32. Similarly, two types of bottom wall portions 43 of the heat-shielding member 20 are prepared: a first bottom wall portion 43X that matches the bottom shape when the first insulating portion 31 is used alone, and a second bottom wall portion 43Y that matches the bottom shape when the first insulating portion 31 and the second insulating portion 32 are used in combination, and one of them is selectively used according to the usage state of the second insulating portion 32.

[0066] The difference between the opening diameter R1 when the opening size of the heat shielding member 20 is increased and the opening diameter R2 when the opening size is decreased is preferably 50 mm (approximately 2 inches) or more. This is because, when the diameter difference between two types of silicon single crystals with different crystal diameters is less than 50 mm, it is possible to pull silicon single crystals of substantially the same quality by fine-tuning other crystal pulling conditions without changing the opening size of the heat shielding member 20. In this way, the opening size of the heat shielding member 20 must be changed when the diameter difference between the two types of silicon single crystals is relatively large, making it difficult to make the quality of the two types of silicon single crystals substantially the same, and when the diameter difference between the straight body parts of the two types of silicon single crystals is 50 mm or more.

[0067] There is no particular upper limit to the difference in the opening diameters. Therefore, for example, in order to pull up silicon single crystals with a diameter of about 200 mm and silicon single crystals with a diameter of about 400 mm in the same CZ pulling furnace, the difference between the large opening diameter and the small opening diameter of the heat shielding member 20 can be set to 200 mm or more.

[0068] The first heat insulating section 31 and the second heat insulating section 32 constituting the heat insulating member 30, and the outer wall section 41, the first inner wall section 42X, the second inner wall section 42Y, the first bottom wall section 43X, and the second bottom wall section 43Y constituting the wall member 40 constitute a part set of a heat shielding member corresponding to two types of opening sizes. The first heat insulating section 31 and the outer wall section 41 are basic parts common to large and small diameters, and the second heat insulating section 32 is an additional part used only for small diameters. The first inner wall section 42X and the first bottom wall section 43X are optional parts used only for large diameters, and the second inner wall section 42Y and the second bottom wall section 43Y are optional parts used only for small diameters.

[0069] As described above, when pulling up a large-diameter (e.g., 395 mm) silicon single crystal, the first insulating section 31 is used alone as the insulating member 30, and a first inner wall section 42X that fits into the first insulating section 31 is adopted as the inner wall section 42, and a first bottom wall section 43X that covers the lower end surface of the first insulating section 31 is adopted as the bottom wall section 43.

[0070] On the other hand, when pulling up a small-diameter (e.g., 320 mm) silicon single crystal, both the first insulating section 31 and the second insulating section 32 are used as the insulating member 30, and a second inner wall section 42Y that fits into the second insulating section 32 is adopted as the inner wall section 42, and a second bottom wall section 43Y that covers the lower end surfaces of the first insulating section 31 and the second insulating section 32 is adopted as the bottom wall section 43.

[0071] As described above, the heat shielding member 20 according to this embodiment is configured so that some of its components are shared while other components can be replaced, added, or omitted to change the opening size. This allows two types of silicon single crystals with different crystal diameters to be pulled using the same CZ pulling furnace, thereby reducing the variation in quality between the two types of silicon single crystals with different crystal diameters.

[0072] Furthermore, in the single crystal manufacturing method according to this embodiment, when pulling up a silicon single crystal with a large crystal diameter, a heat shielding member 20 (first heat shielding member) constructed using only the first insulating section 31X is used, and when pulling up a silicon single crystal with a small crystal diameter, a double-structure heat shielding member 20 (second heat shielding member) constructed by combining the first insulating section 31 and the second insulating section 32 is used. Therefore, two types of silicon single crystals with different crystal diameters can be pulled up using the same CZ pulling furnace, and the quality variation between the two types of silicon single crystals with different crystal diameters can be reduced.

[0073] FIG. 6 is a schematic cross-sectional view showing the configuration of a heat shielding member according to the third embodiment of the present invention.

[0074] As shown in FIG. 6, the heat shielding member 20 according to this embodiment is a further modified example of the heat shielding member according to the second embodiment shown in FIG. 4 and FIG. 5, and the heat insulating member 30 is a combination of a first heat insulating section 31, a second heat insulating section 32, and a third heat insulating section 33. The first heat insulating section 31 and the second heat insulating section 32 are the same as those used in the second embodiment. The third heat insulating section 33 is a substantially cylindrical member provided on the inner periphery side of the second heat insulating section 32, and is configured to be detachable from the second heat insulating section 32. That is, the heat insulating member 30 according to this embodiment is obtained by adding the second heat insulating section 32 and the third heat insulating section 33 to the first heat insulating section 31, which is a common part with the first embodiment.

[0075] It is preferable that the difference between the opening diameter R2 (see FIG. 4) when the third insulating section 33 is not used and the opening diameter R3 when the opening size is reduced by using the third insulating section 33 be 50 mm (approximately 2 inches) or more. This is because, when the diameter difference between two types of silicon single crystals with different crystal diameters is less than 50 mm, it is possible to pull silicon single crystals of substantially the same quality by fine-tuning other crystal pulling conditions without changing the opening size of the heat shielding member 20.

[0076] The outer peripheral surface 33a of the third insulating section 33 is a tapered surface that fits the inner peripheral surface 32b of the second insulating section 32 and is in close contact with the inner peripheral surface 32b. The inner peripheral surface 33b of the third insulating section 33 is a tapered surface with an inclination angle close to that of the outer peripheral surface 33a and constitutes the inner peripheral surface 30b of the insulating member 30. When the third insulating section 33 is inserted from the upper opening of the second insulating section 32 to the inside, the outer peripheral surface 33a of the third insulating section 33 is in close contact with the inner peripheral surface 32b of the second insulating section 32 and the two are integrated. The third insulating section 33 can be easily removed from the second insulating section 32 by lifting it upward.

[0077] In this embodiment, the third insulation section 33 is a relatively large member extending over a wide area from the upper end to the lower end of the first insulation section 31 and the second insulation section 32, but it may also be a relatively small member provided only on the lower ends of the first insulation section 31 and the second insulation section 32.

[0078] The wall member 40 includes an outer wall portion 41 that covers the outer peripheral area of ​​the outer peripheral surface 30a and the bottom end surface 30c of the heat insulating member 30, an inner wall portion 42 that covers the inner peripheral surface 30b of the heat insulating member 30, and a bottom wall portion 43 that covers the inner peripheral area of ​​the bottom end surface 30c of the heat insulating member 30. Here, the outer wall portion 41 is the same as that used in the first embodiment, and, like the first heat insulating portion 31, is a component common to the first to third embodiments.

[0079] As the inner wall portion 42, a third inner wall portion 42Z having a shape that fits the inner peripheral surface 33b of the third heat insulating portion 33 is used, and as the bottom wall portion 43, a third bottom wall portion 43Z having an even smaller opening size is used to match the use of the third heat insulating portion 33. Therefore, the shape of the third inner wall portion 42Z is ​​slightly different from that of the second inner wall portion 42Y, and the shape of the third bottom wall portion 43Z is slightly different from that of the second bottom wall portion 43Y.

[0080] The first insulating section 31, the second insulating section 32, and the third insulating section 33 constituting the insulating member 30, and the outer wall section 41, the first inner wall section 42X, the second inner wall section 42Y, the third inner wall section 42Z, the first bottom wall section 43X, the second bottom wall section 43Y, and the third bottom wall section 43Z constituting the wall member 40, constitute a part set of a heat shielding member corresponding to three types of opening sizes. The first insulating section 31 and the outer wall section 41 are basic parts common to the large diameter, medium diameter, and small diameter, the second insulating section 32 and are additional parts common to the medium diameter and small diameter, and the third insulating section 33 is an additional part used only for the small diameter. The first inner wall portion 42X and the first bottom wall portion 43X are optional parts used only for large diameters, the second inner wall portion 42Y and the second bottom wall portion 43Y are optional parts used only for medium diameters, and the third inner wall portion 42Z and the third bottom wall portion 43Z are optional parts used only for small diameters. In this way, according to this embodiment, the options for the opening size of the heat shielding member 20 can be further expanded.

[0081] 7 and 8 are schematic cross-sectional views showing the configuration of a heat shielding member according to a fourth embodiment of the present invention, with FIG. 7 being a completed view and FIG. 8 being an exploded view.

[0082] 7 and 8, a feature of the heat shielding member 20 according to this embodiment is that the bottom wall portion 43 is omitted as a component of a large-diameter heat shielding member. That is, the wall member 40 is composed of an outer wall portion 41 that covers the entire outer peripheral surface 30a and the lower end surface 30c of the heat insulating member 30, and a first inner wall portion 42X that covers the inner peripheral surface 30b of the heat insulating member 30.

[0083] 9 and 10 are schematic cross-sectional views showing the configuration of a heat shielding member according to a fifth embodiment of the present invention, with FIG. 9 being a completed view and FIG. 10 being an exploded view.

[0084] As shown in Figures 9 and 10, the heat-shielding member 20 of this embodiment is a modified example of the heat-shielding member of the fourth embodiment shown in Figures 7 and 8, and differs in that the insulating member 30 is composed of a combination of a first insulating section 31 and a second insulating section 32, and the wall member 40 further includes a bottom wall section 43 in addition to the outer wall section 41 and the second inner wall section 42Y.

[0085] In this way, the bottom wall portion may be omitted when the opening size of the heat shielding member 20 is to be increased, and a bottom wall portion may be added when the opening size of the heat shielding member 20 is to be decreased. In this case, the first heat insulating portion 31 and the outer wall portion 41 can be used as common parts, and by adding the second heat insulating portion 32 and the bottom wall portion 43 and replacing the inner wall portion 42, it is also possible to accommodate small diameters.

[0086] 11 and 12 are schematic cross-sectional views showing the configuration of a heat shielding member according to a sixth embodiment of the present invention, with FIG. 11 being a completed view and FIG. 12 being an exploded view.

[0087] 11 and 12, the heat shielding member 20 according to this embodiment is characterized in that a key-shaped engagement portion is provided at the connection position between the outer wall portion 41 and the inner wall portion 42 in order to strengthen the connection between the two. Specifically, a protrusion 41v that protrudes upward is formed at the lower end (inner circumferential end) of the outer wall portion 41, and the lower end of the inner wall portion 42 is engaged with and fixed to the protrusion 41v provided at the lower end (inner circumferential end) of the outer wall portion 41. When the inner wall portion 42 is placed inside the outer wall portion 41, the lower end of the inner wall portion 42 engages with the protrusion 41v of the outer wall portion 41, and the two are firmly connected.

[0088] It is preferable that the connection points of the parts constituting the wall member 40 have hook-shaped ends that engage with each other to prevent fine powder caused by deterioration of the internal insulating member 30 from falling out, thereby maintaining a sealed state inside the wall member 40. Since the insulating member 30 gradually deteriorates and turns into powder, if the insulating member 30 is not sealed properly by the wall member 40, the fine powder of the insulating member 30 will leak out and have a negative effect on the yield of the single crystal. However, if the joints between the multiple parts constituting the wall member 40 are tightly sealed, it is possible to prevent the fine powder from leaking out.

[0089] 13 and 14 are schematic cross-sectional views showing the configuration of a heat shielding member according to a seventh embodiment of the present invention, with FIG. 13 being a completed view and FIG. 14 being an exploded view.

[0090] As shown in Figs. 13 and 14, the heat shielding member 20 according to this embodiment is a modified example of the heat shielding member according to the sixth embodiment shown in Figs. 11 and 12, and is different from the heat insulating member 30 in that the heat insulating member 30 is made up of a combination of the first heat insulating portion 31 and the second heat insulating portion 32, and the wall member 40 further includes a bottom wall portion 43 in addition to the outer wall portion 41 and the second inner wall portion 42Y. In addition, a hook-shaped engagement portion is provided at the connection position between the outer wall portion 41 and the bottom wall portion 43 in order to strengthen the connection between the outer wall portion 41 and the bottom wall portion 43. Specifically, a protrusion 41v protruding upward is formed at the lower end (inner peripheral end) of the outer wall portion 41, and a hook portion 43v that engages with the protrusion 41v of the outer wall portion 41 is formed at the outer peripheral end of the bottom wall portion 43. When the bottom wall portion 43 is installed inside the outer wall portion 41, the hook portion 43v engages with the protrusion 41v, and the two are firmly connected to each other.

[0091] It is preferable that the connection points of the parts constituting the wall member 40 have hook-shaped ends that engage with each other to prevent fine powder caused by deterioration of the internal insulating member 30 from falling out, thereby maintaining a sealed state inside the wall member 40. Since the insulating member 30 gradually deteriorates and turns into powder, if the insulating member 30 is not sealed properly by the wall member 40, the fine powder of the insulating member 30 will leak out and have a negative effect on the yield of the single crystal. However, if the joints between the multiple parts constituting the wall member 40 are tightly sealed, it is possible to prevent the fine powder from leaking out.

[0092] The heat shielding member 20 according to this embodiment can achieve the same effects as the heat shielding members according to the first and second embodiments. That is, the opening size can be changed to three stages by removing or replacing some of the components. Therefore, the same CZ pulling furnace can be used to pull three types of silicon single crystals with different crystal diameters, and the variation in quality of the three types of silicon single crystals with different crystal diameters can be reduced.

[0093] Although a preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention, and it goes without saying that these modifications are also included within the scope of the present invention.

[0094] For example, in the above embodiment, the first insulation section 31, the second insulation section 32 and the third insulation section 33 are each constructed as a single part, but they may also be made up of a combination of multiple parts divided in the height direction.

[0095] The inner peripheral surface of the inner wall portion 42 constituting the inner peripheral surface of the heat shielding member 20 is a flat surface that slopes obliquely from the upper end to the lower end, but a step may be provided along the way. For example, by providing a step that functions as a handle on a part or the entire circumference of the inner peripheral surface of the inner wall portion 42 in the circumferential direction, the workability of attaching and detaching the inner wall portion 42 can be improved. Such a step may be provided on the first to third heat insulating portions 31 to 33 constituting the heat insulating member 30, and can be provided on all parts housed inside the outer wall portion 41 of the wall member 40.

[0096] Furthermore, in the above embodiment, a heat shielding member used in the production of silicon single crystals by the CZ method is given as an example, but the present invention is not limited to silicon single crystals and can be applied to the production of various single crystals. [Explanation of symbols]

[0097] 1. Single crystal manufacturing equipment 2. Silicon melt 3. Silicon single crystal 10. Chamber 10a Main Chamber 10b Pull chamber 10c Gas inlet 10d Gas outlet 11 Quartz crucible 12 Graphite crucible 13 Rotating shaft 14 Shaft drive mechanism 15 Heater 16 Insulation 17 Wire 18 Wire winding mechanism 20 Heat shielding material 20a opening 30 Insulation materials 30a Outer surface of heat insulating member 30b Inner circumferential surface of heat insulating member 30c Lower end surface of heat insulating member 30d Top surface of heat insulating material 31 First insulation section 31a Outer surface 31b Inner surface 31c Lower end surface 31d Top surface 32 Second insulation section 32a Outer surface 32b Inner surface 32c Lower end surface 32d Top surface 33 Third insulation section 33a Outer surface 33b Inner surface 33c Lower end surface 33d top surface 40 Wall components 41 Exterior wall 41u Tapered surface 41v protrusion 42 Inner wall 42X 1st inner wall section 42Y 2nd inner wall part 42Z 3rd inner wall section 42t tapered surface 43 Bottom wall 43X 1st bottom wall part 43Y Second bottom wall 43Z 2nd bottom wall part 43t tapered surface 43u Tapered surface 43v Hook part

Claims

1. A heat shielding member used in pulling a single crystal by a CZ method, surrounding the single crystal pulled from a melt in a crucible, comprising: A substantially cylindrical heat insulating member; a wall member covering an exposed surface of the heat insulating member; The wall member is An outer wall portion covering at least an outer peripheral surface of the heat insulating member; An inner wall portion covering an inner circumferential surface of the heat insulating member; A bottom wall portion covering a lower end surface of the heat insulating member, The heat insulating member is A substantially cylindrical first insulation portion; A substantially cylindrical second insulation part is provided inside the first insulation part, The second heat insulating section is configured to be detachable from the first heat insulating section, The inner wall portion includes a first inner wall portion that covers an inner circumferential surface of the first heat insulating portion when the first heat insulating portion is used alone, and a second inner wall portion that covers an inner circumferential surface of the second heat insulating portion when the first heat insulating portion and the second heat insulating portion are used in combination, A heat-shielding member characterized in that the difference between the opening diameter of the heat-shielding member when the first insulation section is used alone and the opening diameter of the heat-shielding member when the first insulation section and the second insulation section are used in combination is 50 mm or more.

2. The outer peripheral surface of the first heat insulating portion is covered by the outer wall portion, The inner circumferential surface of the second heat insulating portion is covered by the inner wall portion, The heat shielding member according to claim 1 , wherein when the first insulation section and the second insulation section are used in combination, an outer peripheral surface of the second insulation section is in close contact with an inner peripheral surface of the first insulation section.

3. The bottom wall portion is configured to be detachable from the outer wall portion, The heat shielding member according to claim 1 or 2, wherein the inner wall portion is configured to be detachable from the bottom wall portion and the outer wall portion.

4. 4. The heat shielding member according to claim 1, wherein an upper surface of an inner peripheral end portion of the bottom wall portion connected to a lower end portion of the inner wall portion has a tapered surface inclined radially outward, and the lower end portion of the inner wall portion abuts against the tapered surface.

5. 5. The heat shielding member according to claim 1, wherein a lower end of the outer wall portion connected to an outer peripheral end of the bottom wall portion has a tapered surface inclined radially outward, and the outer peripheral end of the bottom wall portion abuts against the tapered surface.

6. The heat shielding member according to claim 1 , wherein a protrusion is provided at a lower end of the outer wall portion, and a hook portion that engages with the protrusion is provided at an outer circumferential end of the bottom wall portion.

7. A parts set for a heat shielding member used in pulling a single crystal by a CZ method, surrounding the single crystal pulled from a melt in a crucible, comprising: A substantially cylindrical first insulation portion; A substantially cylindrical second insulation part that is detachably provided inside the first insulation part; An outer wall portion covering an outer peripheral surface and a lower end surface of the first heat insulating portion; A first inner wall portion covering an inner circumferential surface of the first heat insulating portion; A second inner wall portion covering an inner circumferential surface of the second heat insulating portion; A bottom wall portion covering a lower end surface of the second heat insulating portion, The first heat shielding member is composed of the first heat insulating portion, the outer wall portion, and the first inner wall portion, A heat-shielding member parts set, characterized in that a second heat-shielding member having an opening diameter smaller than that of the first heat-shielding member is composed of the first insulation portion, the second insulation portion, the outer wall portion, the second inner wall portion and the bottom wall portion.

8. A parts set of a heat-shielding member as described in claim 7, wherein the difference between the opening diameter of the first inner wall portion and the opening diameter of the second inner wall portion is 50 mm or more.

9. A part set for a heat shielding member used in pulling a single crystal by a CZ method, surrounding the single crystal pulled from a molten liquid in a crucible, comprising: A substantially cylindrical first insulation portion; A substantially cylindrical second insulation part that is detachably provided inside the first insulation part; An outer wall portion covering an outer peripheral surface of the first heat insulating portion; A first inner wall portion covering an inner circumferential surface of the first heat insulating portion; A second inner wall portion covering an inner circumferential surface of the second heat insulating portion; A first bottom wall portion covering a lower end surface of the first heat insulating portion; A second bottom wall portion covering the lower end surfaces of the first and second heat insulating portions, the first heat shielding member is composed of the first heat insulating portion, the outer wall portion, the first inner wall portion, and the first bottom wall portion, A heat-shielding member parts set, characterized in that a second heat-shielding member having an opening diameter smaller than that of the first heat-shielding member is composed of the first insulation portion, the second insulation portion, the outer wall portion, the second inner wall portion and the second bottom wall portion.

10. 10. The parts set for a heat shielding member according to claim 9, wherein a difference between an opening diameter of the first inner wall portion and an opening diameter of the second inner wall portion is 50 mm or more.

11. 7. A single crystal manufacturing apparatus comprising: a chamber; a crucible for supporting the melt within the chamber; a heater for heating the melt; a crucible drive mechanism for rotating and raising and lowering the crucible; a crystal pulling mechanism for pulling the single crystal from the melt; and a heat shielding member according to any one of claims 1 to 6, which is installed above the melt, surrounds the single crystal pulled from the melt, and shields it from radiant heat from the heater.

12. A method for producing a single crystal by the CZ method, in which a single crystal is pulled up from a melt in a crucible, characterized in that the single crystal pulled up from the melt is surrounded by a heat shielding member according to any one of claims 1 to 6.

Images