Heat shield member, single crystal pulling device, and method for manufacturing single crystal silicon ingot

Abstract

Provided are a heat shield member, a single crystal pulling device, and a method for producing a single crystal ingot using the single crystal pulling device, with which it is possible to enlarge the pulling speed limit at which a defect-free single crystal can be obtained. This heat shield member (1) is provided in a single crystal pulling device that pulls a single crystal silicon ingot (I) from a silicon melt that is heated by a heater disposed around a quartz crucible and that is stored in the quartz crucible, and is provided with a cylindrical tube section (2) that surrounds the outer peripheral surface of the single crystal silicon ingot, and an annular protrusion section (3) that is at the lower part of the tube section (2). The heat shield member (1) is characterized in that the raised part (3) has an upper wall (3a), a bottom wall (3b), and two vertical walls (3c, 3d), a ring-shaped heat-insulating material (H) is provided in a space surrounded by these walls, and a gap is provided between the heat-insulating material (H) and the vertical wall (3c) on the side adjacent to the single crystal silicon ingot (I).

Description

TECHNICAL FIELD

[0001] The present application relates to a heat shield member, a single crystal pulling apparatus, and a method for manufacturing a single crystal silicon ingot using the single crystal pulling apparatus. BACKGROUND

[0002] Generally, a silicon wafer obtained by subjecting a single crystal silicon ingot grown by a pulling (Czochralski, CZ) method to wafer processing is used as a substrate for semiconductor devices.

[0003] Figure 1 An example of a general single crystal pulling apparatus for growing a single crystal silicon ingot by the CZ method is shown. The single crystal pulling apparatus 100 shown in the figure is provided with a crucible 52 for containing a raw material of a single crystal silicon ingot I in a chamber 51, and the crucible 52 shown in the figure is composed of a quartz crucible 52a and a graphite crucible 52b. A crucible rotation and lift shaft 53 is installed at the lower portion of the crucible 52, and the crucible rotation and lift shaft 53 rotates the crucible 52 in the circumferential direction while lifting the crucible 52 in the vertical direction. Further, a heater 54 is disposed around the crucible 52, and the raw material contained in the crucible 52 is heated to form a silicon melt M.

[0004] A pulling shaft 55 for pulling the single crystal silicon ingot I is provided at the upper portion of the chamber 51, and a seed crystal holder 56 is fixed to the front end of the pulling shaft 55, and a seed crystal S is held on the seed crystal holder 56. Further, a gas introduction port 57 and a gas discharge port 58 are provided at the upper and lower portions of the chamber 51, respectively, and are configured to supply an inert gas from the gas introduction port 57 into the chamber 51, pass it along the outer peripheral surface of the ingot I, and discharge it from the gas discharge port 58 during the growth of the single crystal silicon ingot I.

[0005] In addition, a cylindrical heat shield member 60 is provided in the chamber 51 so as to surround the outer peripheral surface of the ingot I being grown. Figure 2 An example of the structure of the conventional heat shield member 60 is shown. The heat shield member 60 shown in the figure is provided with a cylindrical barrel portion 61 that surrounds the outer peripheral surface of the single crystal silicon ingot I, and a raised portion 62 at the lower portion of the barrel portion 61 (for example, see Patent Document 1). Here, the barrel portion 61 has an inner wall 61a and an outer wall 61b. Further, the raised portion 62 has an upper wall 62a, a bottom wall 62b, and two longitudinal walls 62c and 62d. Furthermore, a heat insulating material (heat storage member) H is provided in the space surrounded by these walls.

[0006] This heat shield member 60 shields the radiant heat from the heater 54 or the silicon melt M, the side wall of the crucible 52, promotes the cooling of the pulled single crystal silicon ingot I, and on the other hand, insulates the outer peripheral surface of the ingot I by the heat insulating material H of the raised portion 62 heated by the heater 54 or the silicon melt M, and suppresses 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 from becoming large.

[0007] The growth of the single crystal silicon ingot I is performed using the above-described apparatus 100 as follows. First, while maintaining the inert gas atmosphere of Ar gas or the like at a reduced pressure in the chamber 51, the raw material substance such as polycrystalline silicon accommodated in the crucible 52 is heated and melted by the heater 54 to produce a silicon melt M. Next, the seed crystal S is dipped in the silicon melt M by lowering the pulling shaft 55, and the crucible 52 and the pulling shaft 55 are rotated in a prescribed direction while the pulling shaft 55 is pulled upward. In this way, the single crystal silicon ingot I can be grown below the seed crystal S.

[0008] In the single crystal silicon ingot I grown using the above-described apparatus 100, various types of Grown-in defects that cause problems in the device formation process are formed. The distribution of the ingot I in the radial plane of the Grown-in defects is known to depend on two factors, namely, the pulling speed V of the crystal and the temperature gradient G of the pulling direction in the single crystal in the solid-liquid interface (for example, refer to Non-Patent Literature 1).

[0009] Figure 3 is a graph showing the relationship of the ratio V / G of the pulling speed V to the temperature gradient G in the solid-liquid interface with respect to the crystal region constituting the single crystal silicon ingot I. As shown in the graph, in the case where the value of V / G is large, the single crystal silicon ingot is dominated by a COP occurrence region 71 that is a crystal region in which Crystal Originated Particles (COP) are formed and detected.

[0010] If the value of V / G is made small and a specific oxidation heat treatment is performed, an OSF potential nucleus region 72 that is a ring-shaped distribution of OSF (Oxidation Induced Stacking Fault) defects is formed, and no COP is detected in the OSF region 72.

[0011] If the value of V / G is further made small, an oxygen precipitation promoting region (hereinafter also referred to as "Pv region") 73 that is a crystal region in which an oxygen precipitate exists and no COP is detected is formed, followed by an oxygen precipitation inhibiting region (hereinafter also referred to as "Pi region") 74 that is a crystal region in which oxygen precipitation is not easily caused and no COP is detected, and a dislocation cluster region 75 that is a crystal region in which a dislocation cluster is detected is formed.

[0012] In a silicon wafer taken from the single crystal silicon ingot I that shows such a defect distribution with respect to V / G, the crystal region other than the COP occurrence region 71 and the dislocation cluster region 75 is generally considered to be a crystal region of a defect-free region, and in general, a silicon wafer taken from these crystal regions can be used as a defect-free silicon wafer.

[0013] Prior Art Documents

[0014] Patent Literature

[0015] Patent Literature 1: Japanese Patent Application Laid-Open (JP A) No. 2004-107132

[0016] Non-Patent Literature

[0017] Non-Patent Literature 1: "The Mechanism of Swirl Defects Formation in Silicon", Journal of Crystal Growth, Vol. 59, 1982, pp. 625-643. SUMMARY

[0018] PROBLEMS TO BE SOLVED BY THE INVENTION

[0019] Since the difference between the value of V / G with respect to the COP occurrence region 71 and the value of V / G with respect to the dislocation cluster region 75 is very small, in order to cultivate a single crystal silicon ingot I having no defects, the pulling speed V must be strictly managed. However, such management of the pulling speed V is very difficult, and a method capable of expanding the range (limit) of the pulling speed V of a crystal from which a single crystal silicon ingot I having no defects can be obtained is desired.

[0020] Therefore, an object of the present application is to provide a heat shield member, a single crystal pulling apparatus, and a method for producing a single crystal silicon ingot using the same, which can expand the limit of the pulling speed of a crystal from which a single crystal silicon having no defects can be obtained.

[0021] MEANS FOR SOLVING THE PROBLEMS

[0022] The gist of the present application, which solves the above problems, is as follows.

[0023] [1] A heat shield member provided in a single crystal pulling apparatus that pulls a single crystal silicon ingot from a silicon melt heated by a heater disposed around a quartz crucible and stored in the quartz crucible, the heat shield member having a cylindrical barrel portion that surrounds an outer circumferential surface of the single crystal silicon ingot and a ring-shaped raised portion at a lower portion of the barrel portion, the heat shield member being characterized in that

[0024] the raised portion has an upper wall, a bottom wall, and two longitudinal walls, and a ring-shaped heat insulating material is provided in a space surrounded by these walls,

[0025] a gap is provided between the longitudinal wall on the side adjacent to the single crystal silicon ingot and the heat insulating material.

[0026] [2] A heat shielding component is disposed in a single crystal pulling device for pulling single crystal silicon ingots from silicon molten metal heated by a heater disposed around a quartz crucible and stored in the quartz crucible. The heat shielding component has a cylindrical portion surrounding the outer peripheral surface of the single crystal silicon ingot and an annular protrusion at the lower part of the cylindrical portion. The heat shielding component is characterized in that...

[0027] The raised portion has an upper wall, a bottom wall, and two longitudinal walls, and the space enclosed by these walls contains annular heat-insulating material.

[0028] The surface of the longitudinal wall on the side adjacent to the single-crystal silicon ingot, on the side of the insulating material, is in contact with the insulating material.

[0029] The difference between the opening radius of the heat shield component and the opening radius of the heat insulation material is greater than 5 mm.

[0030] [3] The heat shielding component according to 1 or 2, wherein,

[0031] The longitudinal wall on the side adjacent to the single-crystal silicon ingot and the bottom wall are formed as one unit.

[0032] [4] The heat shielding component according to any one of 1 to 3, wherein,

[0033] The longitudinal wall on the side adjacent to the single-crystal silicon ingot is made of carbon material.

[0034] [5] A single crystal pulling device comprising the heat shielding component described in any one of 1 to 4.

[0035] [6] A method for manufacturing a single crystal silicon ingot, characterized in that the manufacturing is carried out using the single crystal pulling device described in 5.

[0036] Invention Effects

[0037] According to the present invention, it is possible to expand the limit of the crystal pulling speed at which defect-free single-crystal silicon ingots can be obtained. Attached Figure Description

[0038] Figure 1 This is a diagram illustrating an example of a typical single-crystal pulling device.

[0039] Figure 2 This is a diagram showing an example of a heat-shielding component.

[0040] Figure 3 This is a graph showing the relationship between the pulling speed relative to the temperature gradient at the solid-liquid interface and the crystal regions that constitute a single-crystal silicon ingot.

[0041] Figure 4 (a) A diagram showing an example of stress distribution within a single-crystal silicon ingot. Figure 4(b) represents the ideal temperature gradient G. ideal An example diagram.

[0042] Figure 5 This is a diagram illustrating an example of a heat shielding component according to the present invention.

[0043] Figure 6 This is a diagram showing another example of a heat shielding component according to the present invention.

[0044] Figure 7 This is a diagram showing a heat shield component where the longitudinal wall and the bottom wall are integrated.

[0045] Figure 8 It means to use with Figure 5 The diagram shows the temperature gradient of the single crystal ingot during the cultivation process in the single crystal pulling device with the heat shield component shown.

[0046] Figure 9 It indicates that it is capable of being used. Figure 6 The diagram shows the temperature gradient of the single crystal ingot during the cultivation process in the single crystal pulling device with the heat shield component shown. Detailed Implementation

[0047] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The heat shielding component according to the present invention is a heat shielding component disposed in a single crystal pulling apparatus for pulling a single crystal silicon ingot from a silicon melt heated by a heater disposed around a quartz crucible and stored in the quartz crucible. The heat shielding component comprises a cylindrical portion surrounding the outer peripheral surface of the single crystal silicon ingot and an annular raised portion at the lower part of the cylindrical portion. Here, the raised portion has an upper wall, a bottom wall, and two longitudinal walls, and an annular heat-insulating material is disposed in the space enclosed by these walls.

[0048] As described above, the radial distribution of crystal defects within the single-crystal silicon ingot I depends on the ratio of the pulling speed V to the temperature gradient G, V / G. Here, the pulling speed V determines the amount of interlattice silicon and holes introduced into ingot I. In contrast, the temperature gradient G determines the diffusion rate of interlattice silicon and holes.

[0049] The limit of the pulling speed V of a crystal that can obtain a defect-free single-crystal silicon ingot I (hereinafter also referred to as the "pulling speed limit") can be increased by flattening the radial distribution of crystal defects in ingot I. The critical (V / G)cri for achieving the flattening of the radial distribution of crystal defects can be theoretically determined by the condition that the hole concentration and the interlattice silicon concentration become equal, and is derived from the following equation (1) (for example, see K. Nakamura, R. Suewaka and B. Ko, ECS SolidState Letters, 3(3)N5-N7(2014)).

[0050] [Formula 1]

[0051]

[0052] Here, σ mean Let be the stress at any location within the crystal.

[0053] As can be seen from equation (1), the silicon concentration and hole concentration between the lattice become equal (V / G). cri It depends on the stress within the crystal. (V / G) cri The stress distribution within the crystal can be obtained through calculations such as thermal conductivity calculations. Furthermore, the ideal temperature gradient (hereinafter also referred to as "ideal temperature gradient G") for achieving the flattening of the radial distribution of crystal defects is also known. ideal Since the pulling speed V is constant in the radial direction of spindle I, it can be obtained from the above equation (1).

[0054] [Formula 2]

[0055] G ideal =V / (6.68×10 -4 σ mean +0.159) (2)

[0056] Figure 4 (a) shows an example of stress distribution within a crystal. Figure 4 (b) represents an example of an ideal temperature gradient. If such a gradient could be achieved... Figure 4 (b) shows the ideal temperature gradient G ideal By pulling a single-crystal silicon ingot I at the corresponding pulling speed V, the radial distribution of crystal defects within ingot I can be flattened, thereby maximizing the pulling speed limit.

[0057] The temperature gradient G of the single-crystal silicon ingot I depends on the structure of the heat shield component 60. The inventors, in order to achieve the aforementioned ideal temperature gradient G... ideal The relationship between the structure of the heat shield component 60 and the temperature gradient G was carefully analyzed. As a result, it was determined that increasing the radius (hereinafter referred to as the "opening radius") of the opening O through which the ingot I is inserted in the heat shield component 60 can improve its performance. s Make the temperature gradient G close to G ideal Additionally, the aforementioned opening radius R s Let be the opening radius of the raised portion 62.

[0058] Furthermore, it was found that if the opening radius R is used... s By growing monocrystalline silicon ingots I with a larger heat shield than before, the radial distribution of crystal defects becomes flatter, thereby expanding the pulling speed limit.

[0059] Thus, by increasing the opening radius R s, although it is possible to expand the pulling speed limit, but new problems of crystal bending or crystal deformation are generated. It is considered that this is because, when the opening radius R s is increased, the low temperature portions in the single crystal pulling apparatus 100 observable from the silicon melt M increase, and the silicon melt M is cooled to make the temperature of the silicon melt M unstable. In order to stabilize this temperature of the silicon melt M, it is effective to reduce the opening radius R s .

[0060] Thus, in order to expand the pulling speed limit, it is effective to increase the opening radius R s of the raised portion 62 of the heat shielding member 60, and, in relation to this, it is effective to reduce the opening radius R s from the viewpoint of suppressing crystal bending or crystal deformation, and it is thus judged that the expansion of the pulling speed limit and the suppression of crystal bending or crystal deformation are in a trade-off relationship.

[0061] Therefore, the present inventors and others have conducted intensive research on a method of expanding the pulling speed limit without generating crystal bending or crystal deformation. As a result, a method of not changing the opening radius R s of the heat shielding member 60 but increasing the opening radius R h of the heat insulating material H was conceived.

[0062] As described above, the temperature gradient G of the single crystal silicon ingot I depends on the structure of the heat shielding member 60, but the temperature gradient G is determined by the heat insulating material H that controls the heat input to the surface of the single crystal silicon ingot I. In relation to this, in order to stabilize the temperature of the silicon melt M, it is effective to increase the flow rate of the inert gas such as Ar gas that flows between the single crystal silicon ingot I and the heat shielding member 60, and the flow rate of the inert gas depends on the outer shape of the heat shielding member 60.

[0063] Accordingly, the present inventors and others have found that the opening radius R S of the heat shielding member 60 is not changed but the opening radius R h of the heat insulating material H is increased, whereby it is possible to suppress crystal bending or crystal deformation while making the temperature gradient G close to the ideal temperature gradient G ideal and expanding the pulling speed limit, and the present application has been completed.

[0064] Figure 5 An example of a heat shielding member according to the present application is shown. The heat shielding member 1 shown in the drawing is provided with a cylindrical cylinder portion 2 that surrounds the outer periphery of the single crystal silicon ingot I and a raised portion 3 at the lower portion of the cylinder portion 2. Here, the cylinder portion 2 has an inner wall 2a and an outer wall 2b, and the heat insulating material H is provided between them. Also, the raised portion 3 has an upper wall 3a, a bottom wall 3b, and two longitudinal walls 3c and 3d, and the annular heat insulating material H is provided in the space surrounded by these walls. In addition, the above heat shielding member 1 is configured so that the longitudinal wall 3c is adjacent to the ingot I.

[0065] exist Figure 5 In the heat shield component 1 shown, a gap (space) V is provided between the longitudinal wall 3c and the heat insulation material H. This allows the opening radius R of the heat insulation material H to be contained. h Increase the temperature gradient G of ingot I to make it closer to the ideal temperature gradient G ideal This expands the lifting speed limit. Furthermore, the opening radius R of the heat shield component 1... s As before, this maintains the flow rate of the inert gas between ingot I and heat shield 1, thereby suppressing crystal bending or crystal deformation.

[0066] In conventional heat shield components 60, the wall covering the heat insulation material H is merely a covering component to prevent a portion of the heat insulation material H from falling into the molten silicon M, without changing the opening radius R of the heat shield component 60. s The opening radius R of the insulation material H is... h The present invention, which increases the size of the opening radius to create a difference, is unprecedented.

[0067] In addition, such as Figure 5 As shown, the opening radius R of the heat shield component 1 s The opening radius R of the thermal insulation material H is the distance from the central axis A of spindle I (i.e., the lifting axis of the lifting device) to the surface of spindle I side of the longitudinal wall 3c. h It is the distance from the central axis A of ingot I to the inner wall surface of the insulation material H.

[0068] In the heat shielding component 1 according to the present invention, the opening radius R of the heat shielding component 1 is... s The opening radius R of the insulation material H h The difference R d It only needs to be 60 mm larger than the previous heat shield components. This is in Figure 5 The heat shield component 1 shown can be achieved by setting a gap V between the longitudinal wall 3c and the heat insulation material H.

[0069] As mentioned above, Figure 2 In the conventional heat shield component 60 illustrated, walls 62a to 62d are merely covering components used to prevent a portion of the heat insulation material H from falling into the molten silicon M, and the heat insulation material is seamlessly filled in the space enclosed by these walls. Moreover, each of these walls varies depending on one of the walls 62a to 62d, but is generally constructed with a thickness of about 5 mm to 10 mm.

[0070] Therefore, the opening radius R of the heat shield component 1 s The opening radius R of the insulation material H h The difference R dAlso depending on the thickness of the vertical wall 3c, for example, it can be set to be greater than 5 mm, greater than 6 mm, greater than 7 mm, greater than 8 mm, greater than 9 mm, greater than 10 mm, 12 mm or more, 15 mm or more.

[0071] In the present application, the opening radius of the heat insulating material H is set to be larger than that in the conventional heat shield member 60, and the radial distribution of crystal defects is flattened, thereby expanding the pulling speed limit. From the viewpoint of further expanding the pulling speed limit, the difference R between the opening radii d Preferably, it is 25 mm or more, and more preferably, 70 mm or more. Also from the viewpoint of the increase in the thermal load of the quartz crucible due to the removal of the heat insulating material, the prevention of dislocation of the pulled crystal, and the like, the difference R between the opening radii d Preferably, it is 200 mm or less, and more preferably, 150 mm or less.

[0072] Among the walls constituting the outer shape of the heat shield member 1, in order to transmit the radiant heat from the silicon melt M to the outer peripheral surface of the single crystal silicon ingot I well, at least the vertical wall 3c is preferably constituted by a material having a high thermal conductivity. Also, more preferably, the bottom wall 3b is constituted by a material having a high thermal conductivity.

[0073] As the material having a high thermal conductivity, a carbon material such as graphite or a metal such as molybdenum (Mo) can be given. Among these, since the contamination is less, it is preferable that the walls are constituted by the carbon material.

[0074] The opening radius of the protrusion portion of the heat shield member 1 is preferably set to be 340 mm or more and 460 mm or less. Thereby, it is possible to increase the flow rate of the inert gas such as Ar gas flowing between the single crystal silicon ingot I and the heat shield member, and to increase the stability of the temperature of the silicon melt M. More preferably, it is 350 mm or more and 450 mm or less.

[0075] Also, the opening radius of the heat insulating material H is preferably set to be 355 mm or more and 475 mm or less. Thereby, it is possible to increase the flow rate of the inert gas such as Ar gas flowing between the single crystal silicon ingot I and the heat shield member, and to increase the stability of the temperature of the silicon melt M. More preferably, it is 365 mm or more and 465 mm or less.

[0076] Figure 6 Another example of the heat shield member according to the present application is shown. Also, the same reference numerals are attached to the same structures as those of the heat shield member 1 shown in Figure 5 The same reference numerals are attached to the same structures as those of the heat shield member 1 shown in FIG. 1. In the heat shield member 10 shown in the drawing, unlike the heat shield member 1 shown in FIG. 1, the gap (space) V is not provided between the vertical wall 3c and the heat insulating material H. Instead, the thickness of the vertical wall 3c is made thicker than in the past, and the vertical wall 3c is made to be in contact with the heat insulating material H. Thereby, the opening radius R of the heat insulating material H is made larger than in the heat shield member 1. Figure 5 The same reference numerals are attached to the same structures as those of the heat shield member 1 shown in FIG. 1. In the heat shield member 10 shown in the drawing, unlike the heat shield member 1 shown in FIG. 1, the gap (space) V is not provided between the vertical wall 3c and the heat insulating material H. Instead, the thickness of the vertical wall 3c is made thicker than in the past, and the vertical wall 3c is made to be in contact with the heat insulating material H. Thereby, the opening radius R of the heat insulating material H is made larger than in the heat shield member 1.h Larger than ever before, it can expand the limits of the pulling speed that can be obtained to obtain defect-free crystalline silicon while suppressing crystal bending or crystal defects.

[0077] And, as Figure 7 The heat shielding component 20 shown is preferably integrally formed with the longitudinal wall 3c and the bottom wall 3b on the side adjacent to the monocrystalline silicon ingot I. This allows radiative heat from the bottom wall 3b to be more easily transferred to the ingot I, and enables the temperature gradient G to be closer to the ideal temperature gradient G. ideal .about Figure 5 The same applies to the heat shield component 1 shown.

[0078] and, Figures 5 to 7 In the heat shielding components 1, 10 and 20 shown, the raised portion 3 extends into the cylinder, but heat shielding components with the raised portion 3 extending out of the cylinder are also included in this invention.

[0079] (Single crystal pulling device)

[0080] The single-crystal pulling apparatus according to the present invention is characterized by comprising the heat shielding component described above according to the present invention. Therefore, there are no limitations on the structure other than the heat shielding component, and it can be appropriately configured to grow the desired single-crystal silicon ingot.

[0081] For example, Figure 1 In the single crystal pulling device 100 shown, by applying Figures 5 to 7 The heat shielding components 1, 10, and 20 according to the invention, as illustrated in the illustration, can replace the heat shielding component 60, thus forming a single-crystal pulling device according to the invention. Furthermore, by using the single-crystal pulling device according to the invention, defect-free single-crystal silicon ingots can be grown while suppressing crystal deformation.

[0082] (Manufacturing method of monocrystalline silicon)

[0083] Furthermore, the method for manufacturing monocrystalline silicon according to the present invention is characterized by using the monocrystalline pulling apparatus according to the present invention described above to manufacture silicon crystals. Therefore, there are no limitations on the parts other than using the monocrystalline pulling apparatus according to the present invention, and it is possible to appropriately configure the method to grow the desired monocrystalline silicon ingot.

[0084] For example, Figure 1 The single-crystal pulling device 100 shown can be used for applications. Figure 5 The heat shielding component 1 according to the invention is illustrated. Figure 6The heat shield component 60 is replaced by the heat shield component 10 according to the present invention, and a single-crystal silicon ingot is manufactured as follows. First, in an inert gas environment such as Ar gas under reduced pressure, the chamber 51 is maintained, and the raw material such as polycrystalline silicon contained in the crucible 52 is heated and melted by the heater 54 to form a silicon melt M. Next, the lifting shaft 55 is lowered to immerse the seed crystal S in the silicon melt M, the crucible 52 and the lifting shaft 55 are rotated in a predetermined direction, and the lifting shaft 55 is lifted upward. In this way, crystal bending or crystal deformation can be suppressed to cultivate a defect-free single-crystal silicon ingot.

[0085] Example

[0086] The following describes embodiments of the present invention, but the present invention is not limited to these embodiments.

[0087] <Cultivation of Monocrystalline Silicon Ingots>

[0088] (Example 1 of the invention)

[0089] Monocrystalline silicon was manufactured according to the method for manufacturing monocrystalline silicon according to the present invention. Specifically, in Figure 1 The single crystal pulling device 100 shown uses [the following technology / applied technology] Figure 5 The device shown replaces the heat shield 60 with the heat shield 1 as a single crystal pulling device. The upper wall 3a, bottom wall 3b, and longitudinal walls 3c and 3d of the heat shield 1 are made of graphite material with a SiC coating applied to the surface. The thickness of the upper wall 3a is set to 7 mm, the thickness of the bottom wall 3b is set to 5 mm, the thickness of the longitudinal wall 3c is set to 5 mm, and the thickness of the longitudinal wall 3d is set to 7 mm. Furthermore, the radial width of the gap between the longitudinal wall 3c and the heat insulation material H is set to 100 mm.

[0090] (Example 2 of the invention)

[0091] The same process as in Invention Example 1 was used to manufacture single-crystal silicon. However, in Figure 1 The single crystal pulling device 100 shown uses [the following technology / applied technology] Figure 6 The device shown uses the heat shield 10 to replace the heat shield 60 as a single crystal pulling device. Furthermore, the thickness of the longitudinal wall 3c is set to 50 mm. All other conditions are exactly the same as in Invention Example 1.

[0092] (Comparative Example)

[0093] use Figure 1 The single-crystal pulling apparatus 100 shown manufactures single-crystal silicon. Other conditions are exactly the same as in the inventive example.

[0094] <Evaluation of Temperature Gradient>

[0095] Figure 8 Showing the use of Figure 5The single-crystal pulling device shown in the heat shield component 1 exhibits both the temperature gradient G and the ideal temperature gradient G of the single-crystal silicon ingot during cultivation. ideal The relationship. For comparison, the use of... Figure 1 The device shown is used to cultivate the crops. To evaluate the temperature gradient G from the ideal temperature gradient G... ideal The deviation, targeting Figure 8 Using the 41 sampling points of the temperature gradient curve shown, calculate the temperature gradient G and the ideal temperature gradient G. ideal The difference between them is calculated, and their mean and standard deviation are determined.

[0096] [Table 1]

[0097] Horizontal Number of sampling points Average value Standard deviation Invention Example 1 41 0.018512 0.019532 Invention Example 2 41 0.026151 0.021762 Comparative Example 41 0.030852 0.024800 .

[0098] Figure 9 Showing the use of Figure 6 The single-crystal pulling device of the heat shield component 10 shown exhibits the temperature gradient G and ideal temperature gradient G of the single-crystal silicon ingot during cultivation. ideal The relationship. For comparison, the use of... Figure 1 The device shown is used for cultivation. Figure 6 The case of the heat shield component 10 shown above is similar to that described above. Figure 5 The same evaluation was performed on the heat shield component 1 shown. The results are shown in Table 1.

[0099] As shown in Table 1, regarding Figure 5 The heat shield component 1 shown is Figure 6 The standard deviation values ​​of both the heat shield component 10 and the comparative example are smaller than those of the comparative example. Compared with the comparative example, the temperature gradient G is closer to the ideal temperature gradient G. ideal .

[0100] <Evaluation of Crystal Deformation>

[0101] In Invention Examples 1 and 2, and the Comparative Example, defect-free monocrystalline silicon ingots were successfully grown. Specifically, the deformation was evaluated using the deformation rate, an indicator of the degree of deformation of the monocrystalline silicon ingots obtained from the Invention Examples and the Comparative Example (see, for example, Japanese Patent Application Publication No. 09-87083). The deformation rate is a value defined for the diameter of the monocrystalline silicon ingot as ((maximum diameter - minimum diameter) / minimum diameter) × 100 (%), which is 0.10 to 0.13% for Invention Example 1, 0.11 to 0.15% for Invention Example 2, and 0.09 to 0.16% for the Comparative Example, thus meeting the quality standards.

[0102] <Evaluation of the lifting speed limit>

[0103] The limit of the pulling speed V at which a crystal silicon free from defects can be obtained was determined for Invention Examples 1, 2 and Comparative Example. The result was 0.019 mm / min for Invention Example 1, 0.018 mm / min for Invention Example 2 and 0.016 mm / min for Comparative Example. Thus, according to the present application, the limit of the pulling speed at which a crystal silicon free from defects can be obtained can be expanded.

[0104] Industrial applicability

[0105] According to the present application, the limit of the crystal pulling speed at which a single crystal silicon free from defects can be obtained can be expanded, and thus the present application is useful in the semiconductor industry.

[0106] Explanation of reference numerals

[0107] 1, 10, 20, 60 - heat shield member, 2, 61 - cylindrical portion, 2a, 61a - inner wall, 2b, 61b - outer wall, 3, 62 - protruding 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 and lifting shaft, 54 - heater, 55 - pulling shaft, 56 - seed holder, 57 - gas inlet, 58 - gas outlet, 71 - COP generation region, 72 - OSF potential nucleus region, 73 - oxygen precipitation promoting region (Pv region), 74 - oxygen precipitation inhibiting region (Pi region), 75 - dislocation cluster region, 100 - single crystal pulling apparatus, A - central axis of ingot, H - heat insulating material, I - single crystal silicon ingot, M - silicon melt, O - opening, R s - opening radius of heat shield member, R h - opening radius of heat insulating material, S - seed crystal.

Claims

1. A heat shielding component disposed in a single-crystal pulling apparatus for pulling single-crystal silicon ingots from molten silicon heated by a heater disposed around a quartz crucible and stored in the quartz crucible, the heat shielding component comprising a cylindrical portion surrounding the outer peripheral surface of the single-crystal silicon ingot and an annular bulge at the lower part of the cylindrical portion, The feature of this heat shield component is that... The raised portion has an upper wall, a bottom wall, and two longitudinal walls, and the space enclosed by these walls contains annular heat-insulating material. The heat insulation material is in contact with a portion of the surface of the heat insulation material side of the upper wall, and there is a gap between the surface of the heat insulation material side of the longitudinal wall adjacent to the single crystal silicon ingot and the heat insulation material, so that the surface of the heat insulation material side of the longitudinal wall and the heat insulation material are not in contact, and the opening diameter of the raised portion is 340 mm or more and 460 mm or less, and the opening diameter of the heat insulation material is 350 mm or more and 475 mm or less.

2. The heat shielding component according to claim 1, wherein, The difference between the opening radius of the raised portion and the opening radius of the thermal insulation material is more than 15 mm.

3. The heat shielding component according to claim 1 or 2, wherein, The insulation material is in contact with a portion of the surface of the insulation material side of the bottom wall.

4. A single crystal pulling device comprising a heat shielding component as described in any one of claims 1 to 3.

5. A method for manufacturing a single-crystal silicon ingot, characterized in that, It is manufactured using the single crystal pulling apparatus described in claim 4.

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