Heating device, silicon single crystal manufacturing device, and method for manufacturing silicon single crystal

Abstract

To provide a heating device that can stabilize oxygen concentration for each silicon single crystal and can inhibit a lifetime from being shortened.SOLUTION: A heating device for heating a crucible storing a silicon melt on a silicon single crystal manufacturing device for manufacturing a silicon single crystal by a Czochralski method while applying a horizontal magnetic field to a silicon melt includes a graphite heat generating part having a shape in which a cylindrical shape surrounding the crucible is partially chipped.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a heating device, a silicon single crystal manufacturing device, and a silicon single crystal manufacturing method. [Background technology]

[0002] As a method for producing silicon single crystals, the MCZ (magnetically coupled Czochralski) method, in which a horizontal magnetic field is applied to a silicon melt, is sometimes used. When a horizontal magnetic field is applied to a silicon melt using the MCZ method, the direction of convection in a virtual plane perpendicular to the direction of application of the horizontal magnetic field in the silicon melt may be clockwise (hereinafter, sometimes referred to as "right vortex mode") or counterclockwise (hereinafter, sometimes referred to as "left vortex mode").

[0003] Whether the convection mode is the right vortex mode or the left vortex mode is random, and the concentration of oxygen taken into the silicon single crystal varies depending on the convection mode and the environment inside the furnace. In order to obtain a silicon single crystal with a stable oxygen concentration, it is important to control the convection mode of the silicon melt during pulling. For this reason, various methods for controlling the convection mode of the silicon melt in the crucible have been studied (for example, see Patent Document 1).

[0004] Patent Document 1 discloses a heater having a first heating region and a second heating region, each of which is semi-cylindrical with a central angle of 180°. The second heating region is thicker than the first heating region and has a smaller resistance value than the first heating region. The heater is arranged such that the first heating region is located on one side and the second heating region is located on the other side of a vertical imaginary plane including the central axis of the crucible and the central magnetic field line of the horizontal magnetic field. Patent Document 1 discloses a method in which such a heater is used to apply the same voltage to the first heating area and the second heating area, causing the first heating area to heat at a higher temperature than the second heating area, and making the thermal environment inside the furnace asymmetrical with respect to the central axis of the crucible, thereby fixing the convection mode to one of the right vortex mode and the left vortex mode, and eliminating variations in oxygen concentration due to the convection mode. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-151502 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the method disclosed in Patent Document 1, the first heating region, which is thinner than the second heating region, generates heat at a higher temperature than the second heating region, so that the rate of thinning (the rate at which the thickness becomes thinner) caused by the reaction of graphite constituting the heater is faster in the first heating region than in the second heating region. Therefore, if the heater is used for a long period of time, the ratio of the thickness of the first heating region to the second heating region changes, and the ratio of the resistance values ​​also changes. If the heating state of the crucible changes due to such a change in the ratio of the resistance values, the oxygen concentration of the silicon single crystal may change. In addition, since the rate of thinning of the first heating region is faster than that of the second heating region, the lifetime of the heater may be shortened.

[0007] The present invention aims to provide a heating device, a silicon single crystal manufacturing apparatus, and a silicon single crystal manufacturing method that can stabilize the oxygen concentration in each silicon single crystal and prevent the lifetime from being shortened. [Means for solving the problem]

[0008] The heating device of the present invention is a silicon single crystal manufacturing apparatus that produces silicon single crystals by the Czochralski method while applying a horizontal magnetic field to a silicon melt, and is a heating device that heats a crucible that contains a silicon melt, and is equipped with a graphite heating section having a cylindrical shape surrounding the crucible with a portion of it missing.

[0009] In the heating device of the present invention, it is preferable that the heat generating portion has a shape in which a part of the cylindrical shape is notched over the entirety in the vertical direction.

[0010] In the heating device of the present invention, it is preferable that the heat generating portion has a shape in which a circular arc region having a central angle of 10° or more and less than 180° is missing in a plan view seen from vertically above.

[0011] The silicon single crystal manufacturing apparatus of the present invention is a silicon single crystal manufacturing apparatus that produces silicon single crystals by the Czochralski method while applying a horizontal magnetic field to a silicon melt, and includes a crucible that contains the silicon melt, the above-mentioned heating device that heats the crucible, and a magnetic field application unit that applies the horizontal magnetic field to the silicon melt, and the heating device is arranged so that the missing portion of the heating unit is located on one side of a vertical imaginary plane that includes the central axis of the crucible and the central magnetic field line of the horizontal magnetic field.

[0012] The method for producing a silicon single crystal of the present invention is a method for producing a silicon single crystal by the Czochralski method using the above-mentioned silicon single crystal production apparatus while applying the horizontal magnetic field to the silicon melt, and includes a silicon melt production step of melting the silicon raw material in the crucible to produce the silicon melt, a magnetic field application step of applying the horizontal magnetic field to the silicon melt to fix the direction of convection of the silicon melt to one direction in a virtual plane perpendicular to the central magnetic field line, and a growth step of growing the silicon single crystal by pulling up a seed crystal immersed in the silicon melt. [Brief description of the drawings]

[0013] [Figure 1]1A and 1B are diagrams showing a heating device according to an embodiment, in which (A) is a perspective view and (B) is a plan view. [Diagram 2] 1 is a vertical cross-sectional view showing a schematic configuration of a silicon single crystal manufacturing apparatus according to an embodiment. [Diagram 3] FIG. 2 is a schematic plan view showing a heater and a magnetic field application unit according to the embodiment. [Figure 4] 1 is a block diagram of a main part of a silicon single crystal manufacturing apparatus according to an embodiment. FIG. [Diagram 5] 1 is a flowchart showing a method for producing a silicon single crystal according to an embodiment. [Figure 6] FIG. 10(A) is a perspective view showing a heating device according to a modified example, and FIG. 10(B) is a perspective view showing a heating device according to another modified example. [Figure 7] FIG. 2A is a schematic diagram showing the arrangement of a crucible and a heating device in a comparative example, and FIG. 2B is a schematic diagram showing the arrangement of a crucible and a heating device in an example. [Figure 8] 13 is a graph showing calculation results of temperature distribution in the radial direction of the crucible in the silicon melt of the comparative example and the example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] [Embodiment] [Configuration of heating device] First, the configuration of a heating device according to an embodiment of the present invention will be described. FIG. 1 shows a heating device, where (A) is a perspective view and (B) is a plan view.

[0015] 1(A) and 1(B) is used to heat a crucible of a silicon single crystal manufacturing apparatus that manufactures silicon single crystals by the Czochralski method while applying a horizontal magnetic field to a silicon melt. The heating device 4 includes a graphite heating part 40, a first terminal 43, and a second terminal 44.

[0016] The heating part 40 is formed in a shape in which a part of the cylindrical shape surrounding the crucible is missing over the entire direction of the central axis 4C of the heating part 40 (hereinafter, sometimes referred to as the "heating device central axis 4C"), that is, in a planar view, in a circular arc shape. The heating part 40 is preferably formed in a shape missing a circular arc-shaped region 45 (hereinafter, sometimes referred to as the "missing region 45") with a central angle θ of 10° or more and less than 180° in a planar view. The heating part 40 is preferably formed with a uniform thickness over the entire circumferential direction. The heating part 40 is preferably formed with a plurality of upper slits 41 extending downward from the upper end and a plurality of lower slits 42 extending upward from the lower end, which are alternately arranged in the circumferential direction. The upper slits 41 and the lower slits 42 are preferably equal in width dimension to each other and the cut depths along the vertical direction are also preferably equal to each other. In addition, the intervals between the upper slits 41 and the lower slits 42 are preferably equal over the entire circumference of the heating device 4.

[0017] The inner diameter, outer diameter and height of the heating part 40 may be set according to the diameter of the straight body of the silicon single crystal, the length of the entire silicon single crystal, the outer diameter of the crucible or the inner diameter of the heat insulating material surrounding the heating part 40. For example, in the case of a silicon single crystal for a silicon wafer having a diameter of 300 mm (diameter 301 mm or more and 340 mm or less), the inner diameter of the heating part 40 is preferably 840 mm or more and 1000 mm or less, the outer diameter is preferably 880 mm or more and 1040 mm or less, and the height is preferably 400 mm or more and 800 mm or less. In the case of a silicon single crystal for a silicon wafer having a diameter of 450 mm (diameter 451 mm or more and 510 mm or less), the inner diameter of the heating part 40 is preferably 1060 mm or more and 1200 mm or less, the outer diameter is preferably 1120 mm or more and 1260 mm or less, and the height is preferably 600 mm or more and 1000 mm or less.

[0018] The first terminal 43 and the second terminal 44 are provided at opposing positions on the underside of the heat generating unit 40 with the heating device central axis 4C in between, so as to extend downward from the lower end of the portion partitioned by the two lower slits 42, and may be formed integrally with the heat generating unit 40 or may be formed separately from the heat generating unit 40. One of the first terminal 43 and the second terminal 44 is electrically connected to the anode of a power supply (not shown), and the other terminal is electrically connected to the cathode of the power supply or a ground electrode. For example, when a current is applied from the first terminal 43 to the second terminal 44, the region in the heating part 40 where the current flows between the first terminal 43 and the second terminal 44 in a plan view, that is, the region to the right of the imaginary line connecting the first terminal 43 and the second terminal 44 in Fig. 1(B) generates heat, but the left region where no current flows does not generate heat. However, the temperature of the left region increases due to heat transfer from the right region, and the entire heating part 40 heats the crucible arranged inside. The number of terminals for passing a current through the heat generating portion 40 is not limited to two, and may be three or more.

[0019] [Configuration of silicon single crystal manufacturing equipment] Next, the configuration of a silicon single crystal manufacturing apparatus equipped with the heating device of the present invention will be described. Fig. 2 is a vertical cross-sectional view showing a schematic configuration of a silicon single crystal manufacturing apparatus, Fig. 3 is a schematic plan view showing a heater and a magnetic field application unit, and Fig. 4 is a block diagram of a main part of the silicon single crystal manufacturing apparatus.

[0020] 2 is an apparatus for producing silicon single crystals SM by the MCZ method, and pulls up a silicon single crystal SM having a neck portion SM1, a shoulder portion SM2, a straight body portion SM3, and a tail portion (not shown) while applying a horizontal magnetic field to silicon melt M. The silicon single crystal production apparatus 1 includes a chamber 2 that forms an outer shell, a crucible 3 disposed in the center of the chamber 2, and a heating device 4 disposed around the inside of the crucible 3.

[0021] The crucible 3 has a double structure consisting of an outer graphite crucible 3A and an inner quartz crucible 3B, and the quartz crucible 3B contains silicon melt M. The graphite crucible 3A and the quartz crucible 3B are cylindrical containers with bottoms, and are circular in plan view when viewed vertically from above. The crucible 3 is fixed to the upper end of a support shaft 5 that can rotate and move up and down.

[0022] Outside the heating device 4 , a cylindrical heat insulator 6 is provided along the inner surface of the chamber 2 .

[0023] A pulling shaft 7 is disposed above the crucible 3 and coaxially with the support shaft 5. The pulling shaft 7 is formed of a wire, etc. A seed crystal SC is attached to the lower end of the pulling shaft 7.

[0024] In the chamber 2, a cylindrical heat shield 8 is disposed above the silicon melt M in the crucible 3 to surround the silicon single crystal SM being grown. The thermal shield 8 blocks radiant heat from the silicon melt M, the side wall of the crucible 3, and the heater to the silicon single crystal SM during growth, thereby suppressing a temperature rise of the silicon single crystal SM.

[0025] A gas inlet 2A is provided at the top of the chamber 2 to introduce an inert gas such as argon gas into the chamber 2. A gas exhaust port 2B is provided at the bottom of the chamber 2 to suck and exhaust gas from within the chamber 2 by driving a vacuum pump (not shown).

[0026] As shown in FIG. 3, the silicon single crystal manufacturing apparatus 1 further includes a magnetic field application unit 16. The magnetic field application unit 16 includes a first magnetic body 16A and a second magnetic body 16B, each of which is formed of an electromagnetic coil. The first magnetic body 16A and the second magnetic body 16B are provided outside the chamber 2 so as to face each other with the crucible 3 in between. The magnetic field application unit 16 applies a horizontal magnetic field such that, in a plan view, a central magnetic field line 16C passing through the central axis of the electromagnetic coil intersects with a central axis 3C of the crucible 3 (hereinafter, may be referred to as the "crucible central axis 3C") and is in a direction from the second magnetic body 16B to the first magnetic body 16A (the upward direction indicated by the arrow indicating the central magnetic field line 16C in FIG. 3, and the direction from the front to the back of the paper in FIG. 2).

[0027] The heat insulating material 6 is disposed so that its central axis is coaxial with the central axis 3C of the crucible. The heating device 4 is disposed so that the heating device central axis 4C is coaxial with the crucible central axis 3C. The heating device 4 is disposed so that the missing region 45 of the heating part 40 is located on the left side of a vertical imaginary plane VF including the crucible central axis 3C and the central magnetic field line 16C. The heating part 40 is also disposed so that a virtual line connecting the first terminal 43 and the second terminal 44 overlaps with the vertical imaginary plane VF in a plan view.

[0028] When the heat generating part 40 arranged in this way generates heat, the heating temperature of the first part 31A located on the left side of the vertical imaginary plane VF in the crucible 3 becomes lower than the heating temperature of the second part 31B located on the right side. The silicon melt M in the crucible 3 is heated so that the temperature of the part located on the left side becomes lower than the temperature of the part located on the right side. When the silicon melt M is heated in this way, an upward flow of the silicon melt M is stably generated on the right side of the crucible 3, and a downward flow is stably generated on the left side of the crucible 3. When a horizontal magnetic field is applied to the silicon melt M in this state, the convection is fixed counterclockwise regardless of the timing of the application, resulting in a left vortex mode. The heating device 4 may be positioned so that the heating temperature of the first portion 31A and the heating temperature of the second portion 31B are different, and may be positioned in a rotated state from the state shown in Figure 3 so that the arc-directional center 45A of the missing area 45 does not overlap with the vertical imaginary plane VF in a planar view.

[0029] 4, silicon single crystal manufacturing apparatus 1 further includes power supply 17, raw material supply unit 18, crucible rotation drive unit 19, pull-up drive unit 20, input unit 21, memory unit 22, and control unit 23. Magnetic field application unit 16, power supply 17, raw material supply unit 18, crucible rotation drive unit 19, pull-up drive unit 20, input unit 21, and memory unit 22 are connected to control unit 23 so as to be able to transmit and receive various information.

[0030] The magnetic field application unit 16 applies a horizontal magnetic field of a predetermined strength to the silicon melt M based on the control of the control unit 23. The power source 17 supplies a predetermined amount of power to each of the heat generating sections 40 under the control of the control section 23 . The raw material supply unit 18 charges the silicon raw material into the crucible 3 under the control of the control unit 23 . Under the control of the control unit 23, the crucible rotation drive unit 19 rotates the crucible 3 at a predetermined speed in a predetermined direction. The lifting drive unit 20 raises and lowers the lifting shaft 7 based on the control of the control unit 23. In addition, the lifting drive unit 20 rotates the lifting shaft 7 at a predetermined speed in the opposite direction to or in the same direction as the rotation direction of the support shaft 5 based on the control of the control unit 23.

[0031] The input unit 21 is configured with, for example, a touch panel or physical buttons. The input unit 21 is used for inputting various settings, and outputs a signal corresponding to the input operation to the control unit 23. The storage unit 22 is configured with a well-known storage device such as a HDD (Hard Disk Drive), etc. The storage unit 22 stores various information necessary for controlling the pulling of the silicon single crystal SM. The control unit 23 includes a CPU (Central Processing Unit). The control unit 23 controls the pulling of the silicon single crystal SM by the CPU executing a program stored in the storage unit 22.

[0032] [Method for producing silicon single crystal] Next, a description will be given of a method for producing a silicon single crystal SM using the silicon single crystal production apparatus 1. Fig. 5 is a flow chart showing a method for producing a silicon single crystal.

[0033] First, the operator operates the input unit 21 to input the pulling conditions for the silicon single crystal SM to be produced. As shown in FIG. 5, the control unit 23 acquires the inputted raising condition (step S1). Thereafter, the control unit 23 performs the manufacturing process of the silicon single crystal SM based on the acquired pulling conditions. Specifically, while maintaining an inert gas atmosphere under reduced pressure within chamber 2, turning off heating device 4 (not supplying power to heating device 4), and not applying a horizontal magnetic field, control unit 23 controls raw material supply unit 18 to load silicon raw material into crucible 3, and then controls crucible rotation drive unit 19 to rotate crucible 3 in one direction (step S2).

[0034] Next, the control unit 23 controls the power source 17 to heat the crucible 3 with the heat generating unit 40 of the heating device 4, thereby melting the silicon raw material and generating a silicon melt M (step S3: silicon melt generating step).

[0035] Thereafter, the control unit 23 controls the magnetic field application unit 16 to start applying a horizontal magnetic field to the silicon melt M (step S4: magnetic field application step). By the process of step S4, an upward flow of the silicon melt M is stably generated on the right side of the crucible 3, and a downward flow is stably generated on the left side of the crucible 3. Therefore, when the horizontal magnetic field acts on the silicon melt M, the convection of the silicon melt M is fixed counterclockwise and becomes a left vortex mode.

[0036] The control unit 23 controls the pulling drive unit 20 while continuing to apply the horizontal magnetic field at the timing when the convection of the silicon melt M is fixed to the left vortex mode, to grow a silicon single crystal SM (step S5: growing step). In step S5, under the control of the control unit 23, the pulling drive unit 20 raises and lowers the pulling shaft 7 so as to immerse the seed crystal SC in the silicon melt M and then pull up the seed crystal SC, thereby growing a silicon single crystal SM.

[0037] [Effects of the embodiment] In silicon single crystal manufacturing apparatus 1, heat generating portion 40 is disposed so that the missing portion (missing region 45) of heat generating portion 40 is located on the left side of vertical imaginary plane VF, so that the temperature of the left side portion of silicon melt M can be made lower than the temperature of the right side portion, and a downward flow can be stably generated on the left side. Therefore, by applying a horizontal magnetic field to silicon melt M where a stable downward flow is generated, the convection mode of silicon melt M can be fixed to the left vortex mode regardless of the timing of application of the horizontal magnetic field, and the oxygen concentration in each silicon single crystal SM can be stabilized. In addition, since the heat generating portion 40 is formed with a partially missing portion, the heating temperatures of the first portion 31A and the second portion 31B can be made different from each other even if the thickness of the heat generating portion 40 is made uniform in the circumferential direction and the heat generation temperature of the entire heat generating portion 40 is made substantially uniform. Therefore, the rate of thinning caused by the reaction of graphite can be made substantially uniform over the entire heat generating portion 40, and the lifetime of the heating device 4 can be prevented from being shortened.

[0038] Here, when the heating part 40 is formed in a shape lacking an arc-shaped region with a central angle θ of less than 10°, the lacking part is too small, and the temperatures of 31A and 31B may be almost the same. In this case, the position of the downward flow of the silicon melt M may change disorderly, and the convection mode may become a right vortex mode or a left vortex mode depending on the timing of application of the horizontal magnetic field, and the oxygen concentration of each silicon single crystal SM may not be stabilized. On the other hand, when the heating part 40 is formed in a shape lacking an arc-shaped region with a central angle θ of more than 180°, the lacking part may be too large, and a large power may be required to heat the crucible 3 to a desired temperature, or the crucible may not be able to be heated to the desired temperature. In this embodiment, the heat generating portion 40 is formed in a shape in which an arc-shaped region with a central angle θ of 10° or more and less than 180° in a plan view is missing, so that the occurrence of the above-mentioned problems can be suppressed.

[0039] [Variations] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and various improvements and design changes that do not deviate from the gist of the present invention are also included in the present invention.

[0040] For example, the heating device 4 in which the missing region 45 extends over the entire central axis 4C of the heat generating part 40 has been exemplified, but as shown in Fig. 6(A), the heating device 10 may have the arc-shaped missing region 102 in the heat generating part 101 only on the lower side, or only on the upper side (not shown). Also, as shown in Fig. 6(B), the heating device 11 includes a cylindrical upper heat generating part 111 and a substantially cylindrical lower heat generating part 112 located coaxially with the upper heat generating part 111 below the upper heat generating part 111, and the arc-shaped missing region 113 may be only on the lower heat generating part 112, or only on the upper heat generating part 111 (not shown), or may be both on the upper heat generating part 111 and the lower heat generating part 112. EXAMPLES

[0041] Next, examples of the present invention will be described, but the present invention is not limited to the examples.

[0042] [Numerical simulation conditions] As an example, a numerical simulation was performed to compare the temperature distribution of the silicon melt when a comparative example heating device having a cylindrical heating part was used in a silicon single crystal manufacturing apparatus for manufacturing silicon single crystals by the Czochralski method, with the temperature distribution of the silicon melt when a heating device of the example having a cylindrical heating part with a portion missing was used.

[0043] Comparative Example In the numerical simulation of the comparative example, on the premise that a silicon single crystal manufacturing apparatus having a configuration similar to that of the silicon single crystal manufacturing apparatus 1 of the above embodiment is used, the shape of the heat generating part 121 of the heating device 12 of the comparative example is set to a cylindrical shape as shown in Fig. 7(A). The sizes of the crucible 3 and the heat generating part 121 of the heating device 12 of the comparative example are set as follows. Outer diameter of crucible 3A: 32 inches (812.8 mm) Inner diameter, outer diameter and height of the heat generating part 121 of the heating device 12: 920mm, 960mm, 500mm Further, the positional relationship between the crucible 3 and the heating device 12 of the comparative example was set so that the central axis 3C of the crucible and the central axis 121C of the heating device of the heat generating part 121 were coaxially positioned as shown in FIG. 7(A). Then, the temperature distribution at the boundary between the bottom 33B of the quartz crucible 3B and the silicon melt M in a vertical cross section VD perpendicular to the horizontal plane and including the central axis 3C of the crucible was calculated as the radial temperature distribution of the silicon melt while growing a silicon single crystal under the following growth conditions at the moment when the height of the silicon melt reached about 2 / 3 (66.7%) of the height of the crucible. The bottom 33B of the quartz crucible 3B is a curved portion continuing to the lower end of the cylindrical side section 34B. The vertical cross section VD is a plane perpendicular to the direction of the central magnetic field line of the horizontal magnetic field. Amount of silicon melt: Amount that makes the depth of silicon melt M 2 / 3 of the depth of quartz crucible 3B Horizontal magnetic field: None applied Inert gas (argon gas) flow rate, furnace pressure, crucible rotation speed, crystal rotation speed, and crystal growth speed during silicon single crystal growth: each at a specified value - Shoulder length, diameter and length of straight body of silicon single crystal to be grown: 200mm, 306mm, 600mm Here, the present invention aims to fix the direction of convection of the silicon melt before application of the horizontal magnetic field by biasing the temperature distribution in the radial direction of the crucible 3 in the silicon melt M. For this reason, as described above, the bias in temperature distribution under the condition where no horizontal magnetic field is applied was verified by numerical simulation.

[0044] [Example] In the numerical simulation of the embodiment, as shown in FIG. 7(B), the shape of the heat generating part 131 of the heating device 13 of the embodiment was set to a cylindrical shape of the same size as the heat generating part 121 of the heating device 12 of the comparative example, with a missing arc-shaped missing area 132 with a central angle θ of 60° in a plan view. In addition, the arrangement relationship between the crucible 3 and the heating device 13 of the embodiment was set so that the crucible central axis 3C and the heating device central axis 131C of the heat generating part 131 are located on the same axis, and the arc-direction center 132C of the missing area 132 is located on the X1 direction side with respect to the crucible central axis 3C on the vertical cross section VD, as shown in FIG. In other words, in the comparative example, the entire circumference of the crucible 3 is heated by the heating device 12, whereas in the embodiment, the conditions were set so that the part of the crucible 3 on the X1 direction (one side in the horizontal direction) side is not heated by the heating device 13. Then, the temperature distribution at the boundary between the bottom 33B of the quartz crucible 3B and the silicon melt M in the vertical cross section VD at the point when the height of the silicon melt became approximately 2 / 3 of the height of the crucible while growing a silicon single crystal under the same growth conditions as in the comparative example was calculated as the radial temperature distribution of the crucible in the silicon melt M. The output power of the heating device 13 in the embodiment was set so that the average temperature of the triple point (the periphery of the solid-liquid interface between the silicon single crystal and the silicon melt M) of the silicon single crystal (solid phase), silicon melt (liquid phase), and inert gas (solid phase) during growth was the same as the average temperature of the triple point in the comparative example.

[0045] [evaluation] Calculation results of the temperature distribution in the radial direction of the crucible 3 in the silicon melt M in the comparative example and the example are shown in Fig. 8. As shown in Fig. 8, in the comparative example, although the entire circumference of the crucible 3 is heated by the heating device 12, the temperature on the X2 direction side is higher than the temperature on the X1 direction side, as in the example. This is because even if the entire circumference of the crucible 3 is heated uniformly, small convection currents in the silicon melt are constantly changing, and the moment during growth that is the subject of calculation is a moment when the temperature on the X2 direction side is higher than the temperature on the X1 direction side.

[0046] The temperature distribution was evaluated in a range excluding portions 50 mm outside from each of the ends on the X1 direction side and the X2 direction (the other horizontal direction) side of the silicon melt M. The reason for this is that in the portions 50 mm outside from each of the ends on the X1 direction side and the X2 direction side, heat radiation from the upper end of the side portion 34B is reflected in the temperature of the silicon melt M, and there is a risk that the temperature of the silicon melt due only to heating by the heating devices 12 and 13 cannot be appropriately evaluated. 8, it was confirmed that the temperature gradient (the gradient of the line connecting the temperature 50 mm inside from the end on the X1 side and the temperature 50 mm inside from the end on the X2 side) in the Example was higher than the temperature gradient in the Comparative Example. In other words, it was confirmed that the temperature difference in the X-axis direction in the Example was larger than that in the Comparative Example. From this, it was confirmed that a temperature difference can be created within the silicon melt by heating the crucible using a heating device having a heating part with a cylindrical shape surrounding the crucible and part of it missing. [Explanation of symbols]

[0047] 1...silicon single crystal manufacturing apparatus, 10...heating device, 101...heating section, 11...heating device, 111...upper heating section, 112...lower heating section, 13...heating device, 131...heating section, 16...magnetic field application section, 3...crucible, 4...heating device, 40...heating section, M...silicon melt, SM...silicon single crystal.

Claims

1. In a silicon single crystal manufacturing apparatus for manufacturing a silicon single crystal by the Czochralski method while applying a horizontal magnetic field to a silicon melt, a heating device for heating a crucible that contains the silicon melt, A cylindrical graphite heating portion is provided surrounding the crucible, The heat generating portion is a heating device in which a plurality of upper slits extending downward from an upper end and a plurality of lower slits extending upward from a lower end are formed alternately arranged in a circumferential direction, and the portion other than the upper slits and the lower slits is missing.

2. 2. The heating device according to claim 1, The heating device, wherein the partially missing shape is a shape in which a portion of the cylindrical shape is missing over the entire vertical direction.

3. The heating device according to claim 2, The heating device, wherein the partially missing shape is a shape in which an arc-shaped region with a central angle of 10° or more and less than 180° is missing when viewed in a plan view from vertically above.

4. A silicon single crystal manufacturing apparatus for manufacturing a silicon single crystal by the Czochralski method while applying a horizontal magnetic field to a silicon melt, comprising: a crucible for containing the silicon melt; A heating device according to any one of claims 1 to 3 for heating the crucible; a magnetic field application unit that applies the horizontal magnetic field to the silicon melt, The heating device is arranged so that the missing portion of the heat generating portion other than the upper slit and the lower slit is located on one side of a vertical imaginary plane that includes the central axis of the crucible and the central magnetic field line of the horizontal magnetic field.

5. A method for producing a silicon single crystal by a Czochralski method while applying the horizontal magnetic field to the silicon melt, using the silicon single crystal production apparatus according to claim 4, a silicon melt generating step of melting the silicon raw material in the crucible to generate the silicon melt; a magnetic field application step of applying the horizontal magnetic field to the silicon melt to fix a convection direction of the silicon melt in one direction in a virtual plane perpendicular to the central magnetic field line; a growing step of growing the silicon single crystal by pulling up a seed crystal immersed in the silicon melt.

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