Method for growing single crystal silicon, method for manufacturing silicon wafer, and single crystal pulling device

Abstract

Provided is a method for growing a single crystal silicon, which pulls up a single crystal silicon while applying a horizontal magnetic field to a silicon melt, using a single crystal pulling-up device provided with: a chamber; a crucible for storing a silicon melt; a heating unit for heating the silicon melt; a heat shield disposed above the crucible so as to surround the silicon single crystal pulled up from the silicon melt; and an inert gas supply unit that supplies an inert gas that passes between the single crystal silicon and the heat shield. The heat shield is disposed such that a vertical central axis passing through a central position of an opening of the heat shield is shifted in a direction different from a direction along an application direction of a magnetic field center of the horizontal magnetic field with respect to a vertical rotation central axis of the crucible.

Description

Technical Field

[0001] The invention relates to a method for growing single crystal silicon, a method for manufacturing silicon wafers and a single crystal pulling device. Background Art

[0002] As a method for growing single crystal silicon, the Czochralski method is known. In recent years, the so-called MCZ method, which grows single crystal silicon while applying a horizontal magnetic field to a silicon melt, has been widely used. When a horizontal magnetic field is applied to a silicon melt using the MCZ method, the initial formation is as follows: Figure 1A The situation shown in FIG. 1 is that the clockwise convection C1 in the crucible 3 becomes dominant (hereinafter referred to as the right vortex mode). Figure 1B Any convection mode in which the counterclockwise convection C2 in the crucible 3 becomes dominant (hereinafter referred to as the left vortex mode). Figure 1A and Figure 1B In the figure, the reference symbol MD is the application direction of the magnetic field center of the horizontal magnetic field.

[0003] The convection mode is random, and the oxygen concentration entering the crystal varies depending on the convection mode and the furnace environment. In order to obtain a single crystal silicon with a stable oxygen concentration, it is important to control the convection mode of the silicon melt during pulling. Therefore, various studies have been conducted on methods of controlling the convection mode of the silicon melt in the crucible.

[0004] Patent Document 1 discloses a method for eliminating oxygen concentration deviation caused by convection mode by stably selecting one of two convection modes. Specifically, the convection mode is fixed to one of the two convection modes, and the oxygen concentration deviation of each silicon single crystal is suppressed by changing the cutout shape of the heat shield to make the wind speed of the inert gas uneven.

[0005] Patent document 2 describes a method in which the central axis of heat distribution of the molten silicon is offset from the central axis of the grown silicon single crystal by offsetting the position of the central axis of rotation of the crucible from the position of the pulling axis, thereby fixing the convection mode to one of them and suppressing the oxygen concentration deviation of each silicon single crystal.

[0006] Patent Document 3 describes a method for changing the flow rate of inert gas in the circumferential direction by forming a partial cutout in a heat shield or making the opening of the heat shield elliptical, thereby fixing the convection pattern to one and suppressing the oxygen concentration variation of each silicon single crystal.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2020-083717

[0010] Patent Document 2: Japanese Patent Application Laid-Open No. 04-31387

[0011] Patent Document 3: Japanese Patent Application Publication No. 2019-151503 Summary of the invention

[0012] Technical problem to be solved by the invention

[0013] However, the method described in Patent Document 1 has a problem in that the location where the wind speed change of the inert gas occurs is localized, and the convection pattern may not be fixed.

[0014] Furthermore, the method described in Patent Document 2 has a problem in that the step of bringing the seed crystal into contact with the silicon melt becomes difficult, the probability of growing a single crystal decreases, and the yield rate deteriorates.

[0015] Furthermore, in the method described in Patent Document 3, since the heat insulating effect in the circumferential direction becomes non-uniform, the temperature distribution in the circumferential direction of the crystal becomes large, causing the crystal to bend, and there is a possibility that pulling cannot be performed.

[0016] Furthermore, in the methods described in Patent Documents 1 to 3, the oxygen concentration of the grown single crystal silicon is poorly controllable, and even when the convection mode can be fixed, it is necessary to further adjust the pulling conditions to obtain the desired oxygen concentration.

[0017] The object of the present invention is to provide a method for growing single crystal silicon, a method for manufacturing silicon wafers and a single crystal pulling device, wherein the method for growing single crystal silicon can suppress the oxygen concentration deviation of each single crystal silicon while reliably fixing the convection pattern and controlling the oxygen concentration.

[0018] Solutions for solving technical problems

[0019] The method for growing single crystal silicon of the present invention is characterized in that it uses a single crystal pulling device to pull up the single crystal silicon while applying a horizontal magnetic field to the silicon melt, the single crystal pulling device comprising: a chamber; a crucible for storing the silicon melt; a heating unit for heating the silicon melt; a heat shielding body arranged above the crucible in a manner to surround the single crystal silicon pulled from the silicon melt; and an inert gas supply unit for supplying an inert gas passing between the single crystal silicon and the heat shielding body, wherein the heat shielding body is arranged so that a vertical central axis passing through the center position of an opening of the heat shielding body is offset relative to the vertical rotation central axis of the crucible in a direction different from a direction along the direction of application of the magnetic field center of the horizontal magnetic field.

[0020] In the above-mentioned method for growing a silicon single crystal, the heat shielding body is preferably arranged so that a central axis of the heat shielding body is offset in a horizontal direction orthogonal to the application direction with respect to a rotational central axis of the crucible.

[0021] In the above-mentioned method for growing single crystal silicon, it is preferred that when the surface of the silicon melt observed from above through the opening of the heat shielding body is divided into one side and the other side in the horizontal direction orthogonal to the application direction by a line passing through the center position of the opening and parallel to the application direction, the smaller surface area is set to A and the larger surface area is set to B, and the heat shielding body is arranged in a manner such that A / B is greater than 0.3 and less than 0.96.

[0022] The method for manufacturing a silicon wafer of the present invention is characterized by comprising the above-mentioned method for growing single crystal silicon, and cutting a silicon wafer from the grown single crystal silicon.

[0023] The single crystal pulling device of the present invention is characterized in that it comprises: a chamber; a crucible for storing silicon melt; a heating unit for heating the silicon melt; a heat shielding body arranged above the crucible in a manner to surround the single crystal silicon pulled from the silicon melt; an inert gas supplying unit for supplying an inert gas passing between the single crystal silicon and the heat shielding body; and a magnetic field applying unit for applying a horizontal magnetic field to the silicon melt in the crucible, the heat shielding body being arranged so that a vertical central axis passing through a central position of an opening of the heat shielding body is offset relative to a vertical rotation central axis of the crucible in a direction different from a direction along the direction of application of the magnetic field center of the horizontal magnetic field.

[0024] In the above-mentioned single crystal pulling apparatus, the heat shielding body is preferably arranged such that a central axis of the heat shielding body is offset in a horizontal direction orthogonal to the application direction with respect to a rotational central axis of the crucible.

[0025] In the above-mentioned single crystal pulling device, the heat shielding body is preferably configured so that when the surface of the silicon melt observed from above through the opening of the heat shielding body is divided into one side and the other side in the horizontal direction orthogonal to the application direction by a line passing through the center position of the opening and parallel to the application direction, the smaller surface area is set to A and the larger surface area is set to B, so that A / B is greater than 0.3 and less than 0.96. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1A is a schematic diagram illustrating the convection pattern.

[0027] Figure 1B is a schematic diagram illustrating the convection pattern.

[0028] Figure 2It is a schematic cross-sectional view of a single crystal pulling apparatus according to an embodiment of the present invention.

[0029] Figure 3 It is a schematic plan view illustrating the arrangement of the heat shield according to the embodiment of the present invention.

[0030] Figure 4 This is a graph showing the relationship between the gap distance and the wind speed of the inert gas on the surface of the silicon melt.

[0031] Figure 5 It is a schematic cross-sectional view for explaining the flow of inert gas around the crucible, oxygen evaporation, etc. DETAILED DESCRIPTION

[0032] [Structure of single crystal pulling device]

[0033] The structure of a single crystal pulling apparatus according to an embodiment of the present invention will be described.

[0034] like Figure 2 As shown, the single crystal pulling device 1 is a device for pulling a single crystal silicon SM while applying a horizontal magnetic field to a silicon melt M by the MCZ method. The single crystal pulling device 1 comprises: a chamber 2; a crucible 3, which is arranged in the chamber 2 and stores the silicon melt M; a heater 4; a pulling unit 5, which pulls the single crystal silicon SM; a heat shield 6, which is arranged above the crucible 3 in a manner of surrounding the single crystal silicon SM; a heat insulating material 7; a crucible driving unit 8; and a magnetic field applying unit 9 (refer to Figure 3 ), applying a horizontal magnetic field to the silicon melt M; and an inert gas supply unit 18, supplying an inert gas through the silicon single crystal SM and the heat shielding body 6 between.

[0035] The crucible 3 has a double structure consisting of a quartz crucible 3A and a graphite crucible 3B that accommodates the quartz crucible 3A.

[0036] The crucible driving unit 8 includes a support shaft 11 that supports the crucible 3 from below, and rotates and elevates the crucible 3 at a predetermined speed around the rotation center axis A1.

[0037] The chamber 2 includes a main chamber 12 and a crystal pulling chamber 13 connected to an upper portion of the main chamber 12. The main chamber 12 and the crystal pulling chamber 13 are connected via a gate valve 14.

[0038] The main chamber 12 includes a main body 12A on which the crucible 3, the heater 4, the heat shield 6, etc. are arranged, and a cover 12B that closes the upper surface of the main body 12A. The main body 12A is cylindrical. The cover 12B is provided with an opening 15 for introducing an inert gas such as argon into the main chamber 12. A support portion 17 extending inward is provided between the main body 12A and the cover 12B.

[0039] The crystal pulling chamber 13 is provided with a gas inlet 20 for introducing the inert gas supplied from the inert gas supply unit 18 into the main chamber 12. A gas exhaust port 21 is provided at the lower portion of the main body 12A of the main chamber 12, and the gas in the main chamber 12 is sucked and discharged by the driving of a vacuum pump (not shown).

[0040] The inert gas introduced into the chamber 2 from the gas inlet port 20 descends between the growing single crystal silicon SM and the heat shield 6. Next, the inert gas passes through the gap between the lower end of the heat shield 6 and the liquid surface of the silicon melt M, and then flows toward the outside of the heat shield 6 and further toward the outside of the crucible 3. Then, the inert gas descends outside the crucible 3 and is discharged from the gas exhaust port 21.

[0041] The heater 4 is a heating unit using a resistance heating method, and heats the silicon melt M. The heater 4 is disposed around the crucible 3 and inside the heat insulating material 7. The heater 4 is formed in a cylindrical shape as a whole.

[0042] The pulling unit 5 includes a pulling shaft 24 having a seed crystal SC attached to one end thereof, and a pulling drive unit 23 that moves the pulling shaft 24 upward, downward, and rotates the pulling shaft 24 .

[0043] The central axes of the chamber 2 and the heater 4 coincide with the rotational central axis A1 of the crucible 3 , and the rotational central axis A1 of the crucible 3 coincides with the center of the pulling axis 24 .

[0044] The heat insulating material 7 is cylindrical and has a predetermined thickness in the radial direction. The heat insulating material 7 is arranged outside the heater 4 and inside the chamber 2 .

[0045] The heat shield 6 shields the growing single crystal silicon SM from high temperature radiation heat from the silicon melt M in the crucible 3, the heater 4, and the side wall of the crucible 3. In addition, the heat shield 6 suppresses heat diffusion to the outside near the solid-liquid interface as the crystal growth interface, and controls the temperature gradient in the vertical direction of the center and the periphery of the single crystal silicon SM.

[0046] Furthermore, the heat shield 6 functions as a rectifying cylinder that exhausts evaporated products from the silicon melt M to the outside of the furnace by the inert gas introduced from above the furnace.

[0047] The upper end of the heat shielding body 6 is supported by the support portion 17 of the chamber 2. The heat shielding body 6 is formed into a truncated cone cylindrical shape whose diameter decreases toward the lower end. The heat shielding body 6 is formed into a truncated cone cylindrical shape, and an opening portion 6A having a smaller diameter than the upper end is provided at the lower end of the heat shielding body 6. The center position of the opening portion 6A coincides with the center axis A2 of the heat shielding body 6.

[0048] The shape of the heat shield 6 is not limited to the above-mentioned shape, and may be formed into a truncated cone shape, for example, having a cylindrical main body and a protrusion protruding inwardly from the lower end of the main body in a flange-like manner, and the protrusion is truncated cone-shaped with a diameter decreasing as it goes downward.

[0049] like Figure 3 As shown, the heat shield 6 is arranged so that a vertical center axis A2 passing through the center of the opening 6A of the heat shield 6 is offset from the vertical rotation center axis A1 of the crucible 3 in a horizontal direction orthogonal to the direction MD in which the magnetic field center of the horizontal magnetic field is applied.

[0050] That is, the central axis A2 of the heat shield 6 does not coincide with the rotational central axis A1 of the crucible 3 , and the gap distance G between the outer peripheral surface of the pulled silicon single crystal SM and the opening 6A of the heat shield 6 becomes uneven in the circumferential direction of the heat shield 6 .

[0051] The gap distance G is the distance between the single crystal silicon SM and the opening 6A of the heat shield 6 on a straight line L2 passing through the center position of the opening 6A of the heat shield 6 (the center axis A2 of the heat shield 6) and any position in the circumferential direction of the opening 6A. Figure 3 In order to explain the arrangement of the heat shielding body 6, the offset amount of the heat shielding body 6 is emphasized.

[0052] Specifically, the heat shield 6 is arranged so that when the surface of the silicon melt M observed from above through the opening 6A is divided into one side D1 and the other side D2 in the horizontal direction D by a line L1 passing through the center position of the opening 6A and parallel to the direction MD in which the magnetic field center of the horizontal magnetic field is applied, the smaller surface area is A and the larger surface area is B, and A / B (the ratio of area A to area B) is 0.3 or more and 0.96 or less. In the following description, the region with the smaller area A is referred to as the A region, and the region with the larger area B is referred to as the B region.

[0053] The magnetic field applying unit 9 includes a first magnetic body 9A and a second magnetic body 9B which are electromagnetic coils. The magnetic bodies 9A and 9B are disposed outside the chamber 2 in a manner opposite to each other with the crucible 3 interposed therebetween (at Figure 3 In the figure, the chamber 2 is omitted and the magnetic field applying unit 9 is shown near the crucible 3. ). Thus, the magnetic field applying unit 9 is configured so that the applying direction MD of the magnetic field center passes through the rotation center axis A1 of the crucible 3 and becomes a horizontal direction. That is, the magnetic field center is the horizontal direction passing through the rotation center axis A1 of the crucible 3.

[0054] [Method for growing single crystal silicon]

[0055] Next, a method for growing a silicon single crystal using the above-mentioned single crystal pulling apparatus 1 will be described.

[0056] First, an inert gas is introduced into the chamber 2 without applying a horizontal magnetic field. While maintaining the inert gas atmosphere under reduced pressure, the crucible 3 is rotated and solid raw materials such as polycrystalline silicon stored in the crucible 3 are melted by heating with the heater 4 to generate a silicon melt M.

[0057] Next, while the inert gas is continuously introduced, the magnetic field applying unit 9 is driven to apply a horizontal magnetic field. At this time, the gap distance G becomes non-uniform in the circumferential direction.

[0058] Next, according to pre-set process conditions, the seed crystal SC is dipped into the silicon melt M, and then the silicon single crystal SM is pulled up.

[0059] Here, the relationship between the gap distance G and the wind speed of the inert gas on the surface of the silicon melt will be described. Figure 4 This is a graph showing the relationship between the gap distance G and the wind speed of the inert gas on the surface of the silicon melt. Figure 4 The horizontal axis of the chart is Figure 3 The vertical axis represents the angle θ of the straight line L2, and the vertical axis represents the wind speed of the inert gas on the surface of the silicon melt and the gap distance G. The gap distance G is maximum when the angle θ of the straight line L2 is 270°.

[0060] According to the verification of the inventors, Figure 4 As shown in FIG. 1 , there is a relationship that the larger the gap distance G, the faster the wind speed of the inert gas. Therefore, if the gap distance G is not uniform in the circumferential direction, the wind speed of the inert gas on the surface of the silicon melt is also not uniform in the circumferential direction.

[0061] Next, the oxygen concentration control of single crystal silicon using the non-uniformity of the wind speed of the inert gas is described. In the single crystal silicon growing method of the present invention, the oxygen concentration of single crystal silicon is controlled by fixing the convection pattern and using the relationship between the wind speed of the inert gas and oxygen evaporation.

[0062] First, the fixation of the convection mode will be described. Figure 5 It is a schematic cross-sectional view for explaining the flow of inert gas around the crucible, oxygen evaporation, etc.

[0063] If the wind speed of the inactive gas becomes uneven in the circumferential direction, the temperature distribution around the crucible also becomes uneven. Figure 5 D1 side), then Figure 3 On the right side ( Figure 5The right side of the crucible 3 (D2 side) becomes the smaller area A, and the left side becomes the larger area B, so the flow rate of the inert gas flowing on the right side becomes smaller. As a result, the heat dissipation effect on the right side of the crucible 3 becomes smaller, so the crucible temperature on the right side becomes relatively higher than the crucible temperature on the left side. As a result, the upward flow of the silicon melt M on the right side becomes dominant, and the convection mode becomes a left vortex mode (reference symbol C2).

[0064] On the contrary, the convection mode can be set to the right vortex mode by arranging it on the right side of the heat shielding body 6. In this way, the convection mode can be fixed according to the offset direction of the arrangement of the heat shielding body 6.

[0065] Next, the relationship between the wind speed of the inert gas and oxygen evaporation will be described.

[0066] and Figure 3 Compared with area B in the figure, the wind speed of the inactive gas in area A is slower ( Figure 5 Therefore, the amount of oxygen evaporated from the surface of the silicon melt is reduced (reference numeral E1). On the other hand, the wind speed of the inactive gas in the B region is faster than that in the A region ( Figure 5 Therefore, the amount of oxygen evaporated from the surface of the silicon melt increases (reference symbol E2).

[0067] This is because the wind speed of the inert gas just above the silicon melt is positively correlated with the amount of oxygen evaporated at that position. Since the amount of evaporated oxygen is small, the amount of oxygen in the silicon melt in the A region is relatively increased compared to the B region.

[0068] At this time, the convection mode of the silicon melt M is fixed to the left vortex mode, so the oxygen concentration taken into the single crystal silicon SM is higher than the oxygen concentration of the single crystal silicon grown by arranging the heat shield at the center of the chamber without deviation.

[0069] In addition, the increase in oxygen concentration can be easily controlled by controlling the ratio of A / B without adjusting the pulling conditions. Furthermore, the oxygen concentration can be further adjusted by changing process conditions such as the crucible rotation speed, crystal rotation speed, and inert gas flow rate.

[0070] As described above, by offsetting the heat shield 6 and making the wind speed of the inert gas non-uniform in the circumferential direction, the oxygen concentration of the silicon single crystal can be controlled.

[0071] [Method for manufacturing silicon wafer]

[0072] Silicon wafers can be manufactured by cutting silicon wafers using a wire saw (not shown) from an ingot of single crystal silicon SM grown by the above-mentioned single crystal silicon growing method, and then undergoing normal wafer manufacturing processing steps such as chamfering, grinding, and cleaning.

[0073] According to the above embodiment, the convection mode can be fixed to one of the modes by disposing the center position of the opening 6A of the heat shield 6 offset from the rotation center axis A1 of the crucible 3 in the horizontal direction D. Furthermore, the oxygen concentration of the single crystal silicon SM can be controlled by adjusting the offset amount of the heat shield 6.

[0074] In addition, in the above-mentioned embodiment, the heat shielding body 6 is offset in the horizontal direction D which is orthogonal to the direction MD of application of the magnetic field center of the horizontal magnetic field, but the direction in which the heat shielding body 6 is offset may be an inclined direction which is inclined relative to the horizontal direction D which is orthogonal to the direction MD of application of the magnetic field center of the horizontal magnetic field. That is, the heat shielding body 6 may be arranged so that the central axis A2 of the heat shielding body 6 is offset relative to the rotational central axis A1 of the crucible 3 in a direction different from the direction along the direction MD of application of the magnetic field center of the horizontal magnetic field.

[0075] By shifting the heat shielding body 6 in the tilt direction, the change of A / B can be made more diverse, and the oxygen concentration of the single crystal silicon SM can be finely adjusted.

[0076] The cross-sectional shape of the heat shield 6 perpendicular to the central axis A2 is circular. The cross-sectional shape of the heat shield 6 does not need to be a perfect circle, but can be regarded as a circle if the eccentricity is 0.22 or less in consideration of the dimensional tolerance when manufacturing the heat shield 6.

[0077] [Example]

[0078] The position of the heat shield was moved in the horizontal direction D orthogonal to the direction MD in which the magnetic field center of the horizontal magnetic field was applied, and single crystal silicon was grown while changing the value of the ratio A / B of area A to area B, and the oxygen concentration of the single crystal silicon was compared.

[0079] As shown in Table 1, A / B to be changed is set to the seven conditions shown in Table 1.

[0080] Under these conditions, single crystal silicon with a diameter of 300 mm and a crystal length of 2000 mm was grown. 100 single crystal silicon were grown under each condition.

[0081] [Table 1]

[0082]

[0083] Table 1 shows the fixation rate of the convection mode under each condition and the results of measuring the oxygen concentration at a position 1000 mm below the top of the grown silicon single crystal by Fourier Transform Infrared Spectroscopy (FTIR).

[0084] Regarding the determination of the right-hand scroll mode / left-hand scroll mode, the temperature measuring unit 30 (refer to Figure 2 )Measure T1 and T2 at two points on the surface of silicon melt (reference Figure 5 The temperature measuring unit 30 includes a pair of reflection units 30A and a pair of radiation thermometers 30B, and measures the surface temperature of the silicon melt M.

[0085] The oxygen concentration in Table 1 is expressed as a ratio to the average oxygen concentration of Comparative Example 1 (A / B=1) using the minimum to maximum oxygen concentrations of 100 silicon single crystals under each condition as a reference value.

[0086] As can be seen from Table 1, in order to fix the convection mode, A / B needs to be set to less than 0.96. In addition, if A / B is less than 0.3, the single crystal silicon contacts the heat shield and the single crystal silicon cannot be grown. When A / B is greater than 0.3 and less than 0.96, the convection mode can be fixed to one of them, and the oxygen concentration of the single crystal silicon can be made higher than that of Comparative Example 1.

[0087] That is, it is found that by arranging the thermal shield 6 so that the value of the ratio A / B of the area A to the area B becomes 0.3 or more and 0.96 or less, the convection mode can be more reliably fixed to one of them.

[0088] Furthermore, in order to grow a silicon single crystal having a desired oxygen concentration, it is only necessary to change the rotation speed of the crucible or the rotation speed of the silicon single crystal.

[0089] Description of Reference Numerals

[0090] 1-single crystal pulling device, 2-chamber, 3-crucible, 4-heater (heating part), 5-pulling part, 6-heat shielding body, 6A-opening, 7-insulating material, 9-magnetic field applying part, 18-inert gas supplying part, 23-pulling driving part, 24-pulling axis, A1-rotation center axis, A2-center axis, D-horizontal direction orthogonal to the application direction of the magnetic field center of the horizontal magnetic field, M-silicon melt, MD-application direction of the magnetic field center of the horizontal magnetic field, SC-seed crystal, SM-single crystal silicon.

Claims

1. A method for growing single crystal silicon, which uses a single crystal pulling device to pull the single crystal silicon while applying a horizontal magnetic field to the silicon melt, the single crystal pulling device comprising: a chamber; a crucible for storing the silicon melt; a heating unit for heating the silicon melt; a heat shield disposed above the crucible to surround the single crystal silicon pulled from the silicon melt; and an inert gas supply unit for supplying an inert gas between the single crystal silicon and the heat shield, wherein: The heat shield is arranged so that a vertical central axis passing through a center position of an opening of the heat shield is offset from a vertical rotation central axis of the crucible in a direction different from a direction along an application direction of a magnetic field center of the horizontal magnetic field.

2. The method for growing single crystal silicon according to claim 1, wherein: The heat shielding body is disposed so that a central axis of the heat shielding body is offset in a horizontal direction orthogonal to the application direction with respect to a rotation central axis of the crucible.

3. The method for growing single crystal silicon according to claim 1 or 2, wherein: When the surface of the silicon melt observed from above through the opening of the heat shielding body is divided into one side and the other side in the horizontal direction orthogonal to the application direction by a line passing through the center position of the opening and parallel to the application direction, the heat shielding body is arranged so that A / B becomes greater than or equal to 0.3 and less than or equal to 0.96, with the smaller surface area being A and the larger surface area being B.

4. A method for manufacturing a silicon wafer, comprising the method for growing single crystal silicon according to claim 3, wherein: Silicon wafers are cut out from the grown single crystal silicon.

5. A single crystal pulling device, comprising: Chamber; Crucible, storing molten silicon; A heating unit, for heating the silicon melt; a heat shield disposed above the crucible so as to surround the single crystal silicon pulled from the silicon melt; an inert gas supply unit for supplying an inert gas passing between the single crystal silicon and the heat shield; and a magnetic field applying unit for applying a horizontal magnetic field to the silicon melt in the crucible, The heat shield is arranged such that a vertical central axis passing through a center position of an opening of the heat shield is offset from a vertical rotation central axis of the crucible in a direction different from a direction along an application direction of a magnetic field center of the horizontal magnetic field.

6. The single crystal pulling device according to claim 5, wherein: The heat shielding body is disposed such that a central axis of the heat shielding body is offset from a rotational central axis of the crucible in a horizontal direction orthogonal to the application direction.

7. The single crystal pulling device according to claim 5 or 6, wherein: The heat shield is configured such that when the surface of the silicon melt observed from above through the opening of the heat shield is divided into one side and the other side in a horizontal direction orthogonal to the application direction by a line passing through the center position of the opening and parallel to the application direction, the smaller surface area is set to A and the larger surface area is set to B, so that A / B is greater than or equal to 0.3 and less than or equal to 0.96.

Images