JP2018095528A - Heat shield member, single-crystal pulling-up device, and method of manufacturing single crystal silicon ingot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat shield member, a single-crystal pulling-up device, and a method of manufacturing a single crystal silicon ingot that enable a defect-free single-crystal silicon ingot to be pulled up while suppressing deformation of a crystal.SOLUTION: There is provided a heat shield member 1 provided to a single-crystal pulling-up device for pulling up a single-crystal silicon ingot from a silicon melt stored in a quartz crucible while being heated by a heater arranged at a periphery of the quartz crucible. The heat shield member 1 comprises: a cylindrical cylinder part 2 surrounding an outer peripheral surface of the single-crystal silicon ingot; and a swell part 3 swelling inside or outside the cylinder part 2 at a lower part thereof. In the heat shield member 1, the swell part 3 has an upper wall 3a, a bottom wall 3b, and two vertical walls 3c, 3d, and has a heat insulation material H in a space surrounded with those walls, and thickness at a lower end of the vertical wall on a side adjacent to the single-crystal silicon ingot between the two vertical walls 3c, 3d is larger than that at an upper end thereof.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a heat shielding member, a single crystal pulling apparatus, and a method for manufacturing a single crystal silicon ingot.

  Generally, a silicon wafer obtained by subjecting a single crystal silicon ingot grown by a Czochralski (CZ) method to wafer processing is used as a substrate of a semiconductor device.

  FIG. 1 shows an example of a general single crystal pulling apparatus for growing a single crystal silicon ingot by the CZ method. The single crystal pulling apparatus 100 shown in this figure is provided with a crucible 52 for containing the raw material of the single crystal silicon ingot I in a chamber 51. The crucible 52 shown in this figure is a quartz crucible 52a. And a graphite crucible 52b. A crucible rotation elevating shaft 53 for rotating the crucible 52 in the circumferential direction and raising and lowering the crucible 52 in the vertical direction is attached to the lower part of the crucible 52. A heater 54 is disposed around the crucible 52, and the raw material contained in the crucible 52 is heated to form the silicon melt M.

  A pulling shaft 55 for pulling up the single crystal silicon ingot I is provided at the upper part of the chamber 51, and the seed crystal S is held by a seed crystal holder 56 fixed to the tip. A gas inlet 57 and a gas outlet 58 are respectively provided at the upper and lower portions of the chamber 51, and inert gas is introduced into the chamber 51 from the gas inlet 57 during the growth of the single crystal silicon ingot I. It is configured to be supplied, passed along the outer peripheral surface of the ingot I, and discharged from the gas discharge port 58.

  Further, in the chamber 51, a cylindrical heat shielding member 60 is provided to surround the outer peripheral surface of the growing ingot I. FIG. 2 shows an example of the configuration of a conventional heat shielding member 60. The heat shielding member 60 shown in this figure includes a cylindrical tube portion 61 that surrounds the outer peripheral surface of the single crystal silicon ingot I, and a bulge portion 62 that bulges into the tube at the bottom of the tube portion 61. (For example, refer to Patent Document 1). Here, the cylinder part 61 has the inner wall 61a and the outer wall 61b. In addition, the bulging portion 62 has an upper wall 62a, a bottom wall 62b, and two vertical walls 62c and 62d. And the heat insulating material (heat storage member) H is provided in the space enclosed by these walls.

  Such a heat shielding member 60 shields the radiant heat from the heater 54, the silicon melt M, and the side wall of the crucible 52, and promotes cooling of the single crystal silicon ingot I to be pulled up. The outer peripheral surface of the ingot I is kept warm by the heat insulating material H of the bulged portion 62 that has been heated, and the difference in the temperature gradient in the crystal axis direction between the central portion and the outer peripheral portion of the single crystal silicon ingot I is suppressed.

  FIG. 3 shows another example of a general single crystal pulling apparatus. In the heat shielding member 60 in the apparatus 100 shown in FIG. 1, the bulging portion is configured to bulge into the cylinder, but in the apparatus 200 shown in this figure, the bulging of the heat shielding member 70 is performed. The part is configured to bulge out of the cylinder (see, for example, Patent Document 2).

  Using the apparatus 100 (200), the single crystal silicon ingot I is grown as follows. First, in a state where the inside of the chamber 51 is maintained in an inert gas atmosphere such as Ar gas under reduced pressure, a raw material material such as polycrystalline silicon accommodated in the crucible 52 is heated and melted by the heater 54 to obtain a silicon melt. Let it be M. Next, the pulling shaft 55 is lowered, the seed crystal S is immersed in the silicon melt M, and the pulling shaft 55 is pulled upward while rotating the crucible 52 and the pulling shaft 55 in a predetermined direction. Thus, the single crystal silicon ingot I can be grown below the seed crystal S.

  In the single crystal silicon ingot I grown using the apparatus 100 (200), various types of grown-in defects that are problematic in the device formation process are formed. It is known that the distribution of the grown-in defects in the radial plane of the ingot I depends on two factors, namely, the crystal pulling speed V and the temperature gradient G at the solid-liquid interface (for example, non-patent Reference 1).

  FIG. 4 is a diagram showing the relationship between the ratio V / G of the pulling rate V to the temperature gradient G at the solid-liquid interface and the crystal region constituting the single crystal silicon ingot I. As shown in this figure, when the value of V / G is large, the single crystal silicon ingot is a crystal region in which vacancies are formed and particles (Crystal Originated Particles, COP) resulting from the crystal are detected. It is dominated by the COP generation area 71.

  When the value of V / G is reduced, when a specific oxidation heat treatment is performed, an OSF latent nucleus region 72 distributed in a ring shape called an oxidation induced stacking fault (OSF) is formed. COP is not detected.

  When the value of V / G is further reduced, an oxygen precipitation promoting region (hereinafter also referred to as “Pv region”) 73, which is a crystal region where oxygen precipitates are present and COP is not detected, is followed by oxygen precipitation that is unlikely to occur. An oxygen precipitation suppression region (hereinafter also referred to as “Pi region”) 74 that is a crystal region that is not detected is formed, and a dislocation cluster region 75 that is a crystal region where a dislocation cluster is detected is formed.

  In a silicon wafer taken from the single crystal silicon ingot I exhibiting such a defect distribution according to V / G, the crystal regions other than the COP generation region 71 and the dislocation cluster region 75 are generally defect-free without defects. These are crystal regions that are regarded as regions. Generally, a silicon wafer taken from these crystal regions is a defect-free silicon wafer.

JP 2004-107132 A JP 2004-2064 A

"The Mechanism of Swirl Defects Formation in Silicon", Journal of Crystal Growth, Vol. 59, 1982, pp.625-643

  In recent years, miniaturization and high integration of semiconductor devices have been advanced, and it is required that the silicon wafer is a so-called defect-free silicon wafer that does not include crystal defects such as dislocation clusters and COP (Crystal Originated Particles). .

  For example, in order to grow a single crystal silicon ingot I having a defect-free crystal region using the apparatus 100 shown in FIG. 1, more radiant heat from the heater 54 and the silicon melt M is applied to the outer peripheral surface of the ingot I. Therefore, it is necessary to increase the distance between the lower end of the heat shielding member 60 and the surface of the silicon melt M as compared with the case where the ingot I including a crystal region that is not defect-free is grown.

  However, although the single crystal silicon ingot I including the defect-free crystal region can be grown by using the apparatus configured with the heat shielding member 60 as described above, the horizontal cross-sectional shape of the crystal at the time of growing the ingot I is increased. There has been a problem that “deformation” in which the roundness is lowered occurs. When the crystal is deformed, the quality of the outer peripheral portion of the wafer may be deteriorated when the wafer is used, or there may be a problem that the wafer does not partially satisfy a desired diameter. Such a problem also applies to the case of the apparatus 200 shown in FIG.

  Therefore, an object of the present invention is to provide a heat shielding member, a single crystal pulling apparatus, and a method for manufacturing a single crystal silicon ingot that can pull up a defect-free single crystal silicon ingot while suppressing deformation of the crystal. is there.

  The present inventors diligently studied a heat shielding member that solves the above problems. As a result, it has been found that it is extremely effective to make the lower end thickness larger than the upper end thickness of the vertical wall adjacent to the ingot I among the two vertical walls constituting the bulging portion. The invention has been completed.

That is, the gist of the present invention is as follows.
(1) A heat shielding member provided in a single crystal pulling apparatus that pulls up a single crystal silicon ingot from a silicon melt stored in the quartz crucible by being heated by a heater arranged around the quartz crucible, In the heat shielding member, the member includes a cylindrical tube portion that surrounds the outer peripheral surface of the single crystal silicon ingot, and a bulge portion that bulges out of the tube or outside the tube at a lower portion of the tube portion.
The bulging portion has an upper wall, a bottom wall, and two vertical walls, and has a heat insulating material in a space surrounded by the walls,
Of the two vertical walls, the vertical wall on the side adjacent to the single crystal silicon ingot has a lower end thickness larger than an upper end thickness.

(2) The heat shielding member according to (1), wherein a vertical wall on the side adjacent to the single crystal silicon ingot and the bottom wall are integrally formed.

(3) The heat shielding member according to (1) or (2), wherein a vertical wall on a side adjacent to the single crystal silicon ingot has a carbon material.

(4) The heat shielding member according to any one of (1) to (3), wherein the vertical wall adjacent to the single crystal silicon ingot monotonously increases from the upper end toward the lower end.

(5) About the vertical wall on the side adjacent to the single crystal silicon ingot, the angle between the plane passing through the upper and lower ends and the outer surface of the vertical wall on the side adjacent to the single crystal silicon ingot is 30 ° or more. The heat shielding member according to (4), which is 50 ° or less.

(6) A single crystal pulling apparatus comprising the heat shielding member according to any one of (1) to (5).

(7) A method for producing single crystal silicon, comprising producing using the single crystal pulling apparatus according to (6).

  According to the present invention, a defect-free single crystal silicon ingot can be obtained while suppressing crystal deformation.

It is a figure which shows an example of a common single crystal pulling apparatus. It is a figure which shows an example of a heat shielding member. It is a figure which shows another example of a common single crystal pulling apparatus. It is a figure which shows the relationship between the ratio of the raising speed | rate with respect to the temperature gradient in a solid-liquid interface, and the crystal | crystallization area | region which comprises a single crystal silicon ingot. It is a figure which shows an example of the heat shielding member by this invention. It is a figure explaining the definition of the vertical wall in the heat shielding member by this invention. It is a figure explaining the definition of the vertical wall in the heat shielding member by this invention. It is a figure which shows the heat shielding member in which the vertical wall and the bottom wall were integrally formed.

(Heat shield member)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The heat shielding member according to the present invention is a heat shielding member provided in a single crystal pulling apparatus that pulls up a single crystal silicon ingot from a silicon melt stored in the quartz crucible by being heated by a heater disposed around the quartz crucible. The heat shielding member includes a cylindrical tube portion that surrounds the outer peripheral surface of the single crystal silicon ingot, and a bulge portion that bulges in or out of the tube at the lower portion of the tube portion. Here, the bulging portion has an upper wall, a bottom wall, and two vertical walls, a heat insulating material in a space surrounded by the walls, and a single crystal silicon ingot of the two vertical walls. The adjacent vertical walls are characterized in that the thickness of the lower end is larger than the thickness of the upper end.

  As described above, when the single crystal silicon ingot I having a defect-free crystal region is grown using the apparatus 100 shown in FIG. 1 or the apparatus 200 shown in FIG. Therefore, it is necessary to increase the distance (gap) between the lower end of the heat shielding member 60 (70) and the silicon melt M. However, when an apparatus including the heat shielding member 60 (70) configured as described above is used, an ingot I having a defect-free crystal region is obtained, but the roundness of the horizontal cross-sectional shape of the crystal is reduced. "Is more likely to occur.

  The inventors investigated in detail the cause of the deformation of the crystal. As a result, the surface of the silicon melt M is cooled by the large gap between the silicon melt M and the lower end of the heat shielding member 60 (70) and the silicon melt M, and the vicinity of the surface of the silicon melt M is reduced. It was found that this was due to the smaller radial temperature gradient.

  That is, when the radial temperature gradient in the vicinity of the surface of the silicon melt M becomes small, the difference in the solidification rate due to the crystal orientation becomes remarkable, and single crystals having various crystal orientations on the crystal outer periphery have various correspondingly. Therefore, a “deformation” in which the roundness of the horizontal cross-sectional shape of the crystal is reduced occurs.

  In order to suppress the cooling of the surface of the silicon melt that causes such crystal deformation, it is effective to reduce the gap between the lower end of the heat shielding member 60 (70) and the silicon melt M. However, if the gap is reduced, the condition for obtaining a defect-free crystal is not satisfied.

  It is also possible to suppress the deformation of the crystal by adjusting process parameters such as the rotation speed of the crystal, the rotation speed of the crucible and the magnetic field strength when pulling up the ingot I. However, changing process parameters is difficult because it leads to changes in crystal quality such as oxygen concentration.

  Therefore, the present inventors paid attention to the configuration of the heat shielding member in order to obtain a defect-free crystal in which deformation is suppressed without changing the process parameters. In the heat shielding member 60 (70) of the conventional apparatus 100 (200), the wall that divides the space in which the heat insulating material H is arranged, the material such as carbon fiber constituting the heat insulating material H falls into the silicon melt M. It is merely a cover member for preventing this, and the thickness of the wall is substantially the same.

  As described above, when pulling up the ingot I including the defect-free crystal region, the reason why the gap between the lower end of the heat shielding member 60 (70) and the silicon melt M is increased is that the radiation heat of the silicon melt M is radiated. Is applied to the outer peripheral surface of the ingot I so that the temperature gradient distribution in the radial direction of the ingot I satisfies the condition for obtaining a defect-free crystal. However, if the gap is large, the surface of the silicon melt M is cooled.

  Therefore, the present inventors diligently devised means for satisfactorily irradiating the outer peripheral surface of the single crystal silicon ingot I with the radiant heat of the silicon melt M narrowing the gap between the lower end of the heat shielding member and the silicon melt M. investigated. As a result, the inventors have conceived of increasing the thickness of the vertical wall adjacent to the ingot I among the two vertical walls constituting the bulging portion. Thereby, the radiant heat from the silicon melt M on the outer side in the radial direction of the crucible 52 can be guided to the ingot I, and more radiant heat can be irradiated to the outer peripheral portion of the single crystal silicon ingot I.

  However, since the entire apparatus is cooled when the single crystal silicon ingot I is grown, if the thickness of the vertical wall 3c (3d) is increased, the upper part of the vertical wall 3c (3d) is opposed to the upper part of the apparatus due to the influence of the water-cooled portion on the upper part of the apparatus. It has been found that the cooling of the outer surface of the portion of the ingot I to be accelerated is promoted, which adversely affects the temperature gradient distribution of the ingot I.

  Therefore, as a result of earnestly examining the means for satisfactorily irradiating the outer peripheral surface of the single crystal silicon ingot I without adversely affecting the temperature gradient distribution, the present inventors have determined that the bulging portion is It was conceived that the thickness of the lower end of the vertical wall on the side adjacent to the ingot of the two vertical walls to be formed is larger than the thickness of the upper end.

  FIG. 5 shows an example of a heat shielding member according to the present invention. The heat shielding member 1 shown in this figure includes a cylindrical tube portion 2 that surrounds the outer peripheral surface of the single crystal silicon ingot I, and a bulge portion 3 that bulges into the tube at the bottom of the tube portion 2. . Here, the cylinder part 2 has the inner wall 2a and the outer wall 2b, and the heat insulating material H is provided between these. Moreover, the bulging part 3 has the upper wall 3a, the bottom wall 3b, and the two vertical walls 3c and 3d, and the heat insulating material H is provided in the space enclosed by those walls. In addition, the said heat shielding member 1 is comprised so that the vertical wall 3c may adjoin the ingot I. FIG.

  The heat shielding member 1 illustrated in FIG. 5 is configured such that the thickness of the vertical wall 3c monotonously increases from the upper end U toward the lower end L. As a result, the heat of the bottom wall 3b that receives the radiant heat from the silicon melt M is more conducted to the vertical wall 3c. As a result, the temperature of the vertical wall 3c is increased, and a large amount of radiant heat is transferred from the inner surface of the vertical wall 3c to single crystal silicon. The outer periphery of the ingot I can be irradiated. As a result, the gap between the lower end of the heat shielding member 1 and the surface of the silicon melt M can be narrowed compared to the case where the conventional heat shielding member 60 is used, and the surface of the silicon melt M can be cooled. It is possible to suppress the deformation of the crystal.

In this specification, the vertical wall 3c of the bulge portion 3 of the heat shielding member 1, as shown in FIG. 6, the wall constituting the outer shape of the heat shield member 1 comprises an inner surface 3a _i of the upper wall 3a The portion defined between the plane and the plane including the inner surface 3b _{i of the} bottom wall 3b is indicated. The upper _{U 1} and the lower end _{L 1} of the vertical wall 3c are those on the inner surface of the vertical wall 3c, the thickness _{T u} and the thickness _{T l} of the lower end _{L 1} of the upper _{U 1} is the outer surface 3c _o the vertical wall 3c For the vertical direction.

Further, when the bulging portion is configured to bulge out of the cylinder as in the heat shielding member 70 in the apparatus 200 illustrated in FIG. 3, the vertical wall 3d on the ingot I side is illustrated in FIG. as shown, of the inner wall of the cylindrical portion, partition portions between the horizontal plane P passing through the boundary between the upper wall 3a of the outer wall and the bulging part of the cylindrical portion, and a plane including the inner surface 3b _i of the bottom wall 3b Point to. The upper _{U 2} and the lower end _{L 2} of the vertical wall 3d are those on the inner surface of the vertical wall 3d, the thickness _{T u} and the thickness _{T l} of the lower end _{L 2} of the upper _{U 2} is the outer surface 3d _o of the vertical wall 3d For the vertical direction.

  In addition, when the upper wall 3a and the bottom wall 3b are comprised with the some member, the definition regarding the said vertical wall 3c or 3d shall be based on the member which touches the vertical wall 3c or 3d.

  Since it is difficult to form all the walls constituting the outer shape of the heat shielding member 1 integrally, it is general that a plurality of wall members are combined to form the entire wall. At that time, the position at which the entire wall is divided is not limited. For example, the wall can be divided into three members as shown in FIG. 5, but the radiant heat incident on the bottom wall 3b from the silicon melt M can be more smoothly generated. In order to transmit to the vertical wall 3c, it is preferable that the vertical wall 3c and the bottom wall 3b on the side adjacent to the ingot I are integrally formed as shown in FIG.

The thickness of the upper end of the vertical wall on the ingot I side is preferably 2 mm or more. Thereby, sufficient intensity | strength as a cover member is securable. The upper limit of the thickness of the lower end of the vertical wall on the ingot I side is not particularly limited as long as the thickness of the lower end is larger than the thickness of the upper end in the heat shielding member. The inner surface of 3b can be positioned along an inner surface of 3b _i at any position within the range up to the inner surface of the vertical wall on the side not adjacent to the ingot I side.

  Of the walls constituting the outer shape of the heat shielding member 1, the vertical wall 3 c or 3 d having a lower end thickness larger than the upper end thickness transmits the radiant heat from the silicon melt M well to the outer peripheral surface of the single crystal silicon ingot I. Therefore, it is preferable to use a material having high thermal conductivity. More preferably, the vertical wall 3c and the bottom wall 3b on the side adjacent to the ingot I are preferably made of a material having high thermal conductivity.

  Examples of the material having a high thermal conductivity include carbon materials such as graphite and metals such as molybdenum (Mo). Among these, since there is little contamination, it is preferable to comprise a wall with the said carbon material.

Also, when the thickness of the vertical wall 3c (3d) is configured for increasing an upper end _U 1 toward the _{(U 2)} at the lower end L linearly, the upper end of the vertical wall 3c _U 1 and _{(U 2)} lower L _{1 (L 2)} passes through the plane (i.e., inner surface) and is preferably an angle between the outer surface _3c o (3d _o) of the vertical wall 3c (3d) is 30 ° to 50 °. Thereby, the radiant heat from the silicon melt M is efficiently transmitted to the outer peripheral surface of the single crystal silicon ingot I, and the gap between the lower end of the heat shielding member 1 and the surface of the silicon melt M is made narrower. Can do.

In addition, in the heat shielding member 1 illustrated in FIG. 5, the thickness of the vertical wall 3c increases linearly from the upper end U toward the lower end L. However, in the present invention, the vertical wall 3c (3d) the lower end _L 1 may be larger than the thickness at thick upper _U 1 _{(U 2)} in _{(L 2),} the upper end _U 1 of the vertical wall 3c (3d) _{(U 2)} and the lower end _L 1 _(L 2) The thickness profile between is not limited, and the thickness of the vertical wall 3c (3d) does not need to increase linearly from the upper end U ₁ (U ₂ ) toward the lower end L ₁ (L ₂ ).

(Single crystal pulling device)
The single crystal pulling apparatus according to the present invention includes the above-described heat shielding member according to the present invention. Therefore, the configuration other than the heat shielding member is not limited, and can be appropriately configured so that a desired single crystal silicon ingot can be grown.

  For example, in the single crystal pulling apparatus 100 shown in FIG. 1, by applying the heat shielding member according to the present invention illustrated in FIGS. 5 and 8 instead of the heat shielding member 60, the single crystal pulling apparatus according to the present invention can do. By using the single crystal pulling apparatus according to the present invention, a defect-free single crystal silicon ingot can be grown while suppressing crystal deformation.

(Method for producing single crystal silicon)
The method for producing single crystal silicon according to the present invention is characterized in that a silicon crystal is produced using the above-described single crystal pulling apparatus according to the present invention. Therefore, it is not limited except using the above-described single crystal pulling apparatus according to the present invention, and it can be appropriately configured so that a desired single crystal silicon ingot can be grown.

  For example, in the single crystal pulling apparatus 100 shown in FIG. 1, instead of the heat shielding member 60, an apparatus to which the heat shielding member 1 according to the present invention illustrated in FIGS. 5 and 8 is applied is used as follows. Crystalline silicon ingots can be manufactured. First, in a state where the inside of the chamber 51 is maintained in an inert gas atmosphere such as Ar gas under reduced pressure, a raw material material such as polycrystalline silicon accommodated in the crucible 52 is heated and melted by the heater 54 to obtain a silicon melt. Let it be M. Next, the pulling shaft 55 is lowered, the seed crystal S is immersed in the silicon melt M, and the pulling shaft 55 is pulled upward while rotating the crucible 52 and the pulling shaft 55 in a predetermined direction. Thus, a defect-free single crystal silicon ingot I can be grown while suppressing crystal deformation.

<Growing of single crystal silicon ingot>
(Invention example)
Single crystal silicon was manufactured by the method for manufacturing single crystal silicon according to the present invention. Specifically, as the single crystal pulling apparatus, an apparatus to which the heat shielding member 1 shown in FIG. 8 is applied in place of the heat shielding member 60 in the single crystal pulling apparatus 100 shown in FIG. The heat shielding member 1 uses a graphite material with a SiC coating on the surface, the inner diameter of the vertical wall 3c is 400 mm, the thickness of the upper wall 3a is 6 mm, the thickness of the bottom wall 3b is 8 mm, The inner surface inclination angle was 45 ° with respect to the outer surface. The gap between the lower end of the heat shielding member 1 and the silicon melt M was 73 mm.

(Comparative example)
Single crystal silicon was manufactured using the single crystal pulling apparatus 100 shown in FIG. Here, the thickness of the vertical wall 62c in the heat shielding member 60 was 6 mm in all portions, the upper wall 62a was 6 mm, and the bottom wall 62b was 8 mm. Further, the heat shielding member 60 was arranged so that the gap between the lower end thereof and the silicon melt M was 80 mm. The arrangement of the heat shielding member 60 satisfies the conditions for producing defect-free single crystal silicon. Other conditions are the same as those of the invention examples.

<Evaluation of crystal deformation>
In both the inventive examples and the comparative examples, defect-free single crystal silicon ingots could be grown. However, in the example of the invention, a crystal having a small deformation could be manufactured, whereas in the comparative example, a crystal having a small deformation could not be manufactured. Specifically, the deformation was evaluated using the deformation rate, which is an index indicating the degree of deformation of the single crystal silicon ingot obtained by the inventive example and the comparative example (see, for example, Japanese Patent Laid-Open No. 09-87083). . The deformation rate is a value defined by ((maximum diameter−minimum diameter) / minimum diameter) × 100 (%) for the diameter of the single crystal silicon ingot, and 0.8 to 1.2% for the inventive examples. The comparison example was 1.3 to 2.1%, which did not satisfy the quality standard.

The effects of the present invention capable of producing the modified small crystals, the inner surface inclination angle of the vertical wall 3c was found to be obtained also when the 30 ° and 50 ° with respect to the outer surface 3c _o.

  According to the present invention, a defect-free single crystal silicon ingot can be pulled up while suppressing crystal deformation, which is useful in the semiconductor industry.

1, 60, 70 Heat shielding member 2, 61 Tube portion 2a, 61a Inner wall 2b, 61b Outer wall 3, 62 Bumped portion 3a, 62a Upper wall 3b, 62b Bottom wall 3c, 3d, 62c, 62d Vertical wall 51 Chamber 52 Crucible 52a Quartz crucible 52b Graphite crucible 53 Crucible rotating shaft 54 Heater 55 Lifting shaft 56 Seed crystal holder 57 Gas inlet 58 Gas outlet 71 COP generation region 72 OSF latent nucleus region 73 Oxygen precipitation promotion region (Pv region)
74 Oxygen precipitation suppression region (Pi region)
75 Dislocation cluster region 100,200 Single crystal pulling device H Insulating material I Single crystal silicon ingot M Silicon melt S Seed crystal

Claims (7)

A heat shielding member provided in a single crystal pulling apparatus that pulls up a single crystal silicon ingot from a silicon melt stored in the quartz crucible by being heated by a heater arranged around the quartz crucible, In a heat shielding member comprising: a cylindrical tube portion surrounding an outer peripheral surface of the single crystal silicon ingot; and a bulging portion bulging inside or outside the tube at a lower portion of the tube portion;
The bulging portion has an upper wall, a bottom wall, and two vertical walls, and has a heat insulating material in a space surrounded by the walls,
Of the two vertical walls, the vertical wall on the side adjacent to the single crystal silicon ingot has a lower end thickness larger than an upper end thickness.   The heat shielding member according to claim 1, wherein the vertical wall and the bottom wall adjacent to the single crystal silicon ingot are integrally formed.   The heat shielding member according to claim 1 or 2, wherein a vertical wall on a side adjacent to the single crystal silicon ingot has a carbon material.   The heat shielding member according to any one of claims 1 to 3, wherein the vertical wall on the side adjacent to the single crystal silicon ingot monotonously increases in thickness from the upper end toward the lower end.   About the vertical wall on the side adjacent to the single crystal silicon ingot, the angle between the plane passing through the upper end and the lower end of the vertical wall and the outer surface of the vertical wall on the side adjacent to the single crystal silicon ingot is 30 ° or more and 50 ° or less. The heat shielding member according to claim 4, wherein   A single crystal pulling apparatus comprising the heat shielding member according to claim 1.   It manufactures using the single crystal pulling apparatus of Claim 6, The manufacturing method of the single crystal silicon ingot characterized by the above-mentioned.

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