JP2008162829A - Apparatus and method for manufacturing silicon single crystal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and method for manufacturing a silicon single crystal, with which the distribution of impurities in a grown single crystal ingot can be improved, and it becomes possible to pull the single crystal ingot at high speed, and which is excellent in cost performance. <P>SOLUTION: The apparatus 1 for manufacturing the silicon single crystal is equipped with a control device 13 for controlling the relative position in the pulling shaft direction of a rotating magnetic field device 6 and a crucible 4 so that when the depth of a silicon melt 15 is defined as H, the position in the silicon melt 15 of the maximum intensity of a magnetic field generated by the rotating magnetic field device 6 is located within a depth of 0.3H from the surface of the melt 15. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a silicon single crystal manufacturing technique by the Czochralski method (hereinafter referred to as “CZ method”), and more particularly, a silicon single crystal for crystal growth by a magnetic field pull-up method (hereinafter referred to as “MCZ method”). The present invention relates to a crystal manufacturing apparatus and a manufacturing method.

  The MCZ method is a method of growing a crystal in a state in which the convection of the silicon melt is controlled by applying a magnetic field. Since the flow of the melt containing oxygen generated from the crucible can be controlled, the silicon single crystal This is an effective method for controlling the oxygen concentration in the inside.

  Magnetic fields to be applied in the MCZ method include a horizontal type (HMCZ) and a vertical type (VMCZ) as a static magnetic field, a capsule type having both of these characteristics, and a rotating magnetic field as a dynamic magnetic field.

  The MCZ method using a rotating magnetic field controls the convection of the melt by applying a rotating magnetic field that rotates in the same direction or in the opposite direction with respect to the rotating direction of the crucible, and changing the strength of the rotating magnetic field, The oxygen concentration can be controlled (for example, Patent Document 1).

In order to make the impurity concentration distribution in the silicon single crystal uniform, there is also a method of applying a rotating magnetic field to the lower part of the melt or the intermediate part in the depth direction for the purpose of stirring to make the composition of the melt uniform. Known (for example, Patent Document 2).
JP 59-73491 A JP 63-60189 A

  In recent years, the diameter of silicon single crystal ingots has increased, and a problem has arisen that it takes a long time to pull up the silicon single crystal.

  However, the conventional silicon single crystal manufacturing technology using a rotating magnetic field such as Patent Document 2 cannot pull up the silicon single crystal at high speed while making the impurity distribution in the grown silicon single crystal uniform. .

  In addition, as the diameter of the silicon single crystal ingot increases, it is necessary to use a large rotating magnetic field apparatus, which requires a large amount of cost. Therefore, the rotating magnetic field should be used for growing a large diameter silicon single crystal ingot. Was extremely difficult in terms of cost and convenience.

  Therefore, the problem to be solved by the present invention is that a single crystal manufacturing apparatus using a rotating magnetic field for realizing high-speed pulling and uniform impurity distribution of a silicon single crystal, particularly when growing a large crystal. Even when applied to a pulling furnace, it is to provide a manufacturing apparatus advantageous in terms of cost and convenience.

  As a result of intensive studies to solve the above problems, the present inventors have found the facts described below. That is, the influence of the rotating magnetic field on the flow of the melt is that the rotating magnetic field directly acts on the melt and the melt flows in the direction of rotation of the magnetic field. It hits the inner wall, and at that time, it is important that an upward flow along the inner wall of the crucible is generated due to a difference in rotational speed from the inner wall of the crucible. Then, when the upward flow along the crucible wall surface reaches the melt surface, this time, it flows inward along the melt surface and carries the hot melt near the crucible to the vicinity of the crystal, and melts near the crystal. This means that the temperature can be raised at high speed by making the temperature gradient in the liquid steep.

  In other words, in a manufacturing method in which the impurity distribution in a silicon single crystal is made uniform by applying a rotating magnetic field, it is extremely effective to apply a magnetic field in the vicinity of the melt surface to achieve high-speed pulling of the silicon single crystal. I found out.

  And the present inventors came to complete this invention based on said fact.

  That is, the present invention relates to a crucible containing a silicon melt and a rotating magnetic field that applies a rotating magnetic field that rotates in a plane perpendicular to the pulling direction of the silicon single crystal in an apparatus for manufacturing a silicon single crystal by the Czochralski method. And a position where the maximum intensity of the magnetic field in the melt applied by the rotating magnetic field is controlled to be located near the surface of the melt. The present invention relates to a manufacturing apparatus and a manufacturing method.

  The present invention also relates to a crucible containing a silicon melt and a rotating magnetic field that applies a rotating magnetic field that rotates in a plane perpendicular to the pulling direction of the silicon single crystal in an apparatus for producing a silicon single crystal by the Czochralski method. When the depth of the apparatus and the silicon melt is H, the position where the magnetic field generated by the rotating magnetic field apparatus has the maximum intensity in the silicon melt exists within a depth of 0.3 H from the surface of the melt. In order to achieve this, the present invention relates to the manufacturing apparatus, comprising the rotating magnetic field device and a control device that adjusts a relative position of the crucible in the pulling-up axis direction.

  Further, according to the present invention, in the control device, the region in which the strength is 100% to 50% in the strength distribution in the axial direction of the rotating magnetic field at the interface between the inner wall of the crucible and the silicon melt is defined as the silicon melt. The relative position of the rotating magnetic field device and the crucible in the pulling axis direction is adjusted so as to be within a depth of 0.5H from the surface of the manufacturing method.

Further, the present invention, the width of the pulling axis direction of the core of the rotating magnetic field device, the depth of the silicon melt during pulling start as H _0, and the 0.3H ₀ or less, and, in the center of the core The present invention relates to the manufacturing apparatus, wherein the position is within a depth of 0.3 H from the melt surface.

  According to the present invention, the rotating magnetic field is a plurality of rotating magnetic fields having at least different rotating frequencies among a rotating direction, a rotating frequency, and a magnetic field strength in a plane perpendicular to the pulling direction of the silicon single crystal. The present invention relates to the manufacturing apparatus.

  Further, according to the present invention, in a method for producing a silicon single crystal by the Czochralski method, a rotating magnetic field rotating in a plane perpendicular to the pulling direction of the silicon single crystal is applied to the silicon melt accommodated in the crucible. When the crystal is pulled up and the depth of the silicon melt is H, the position where the magnetic field generated by the rotating magnetic field device has the maximum intensity in the silicon melt is within 0.3H from the melt surface. It is related with the manufacturing method of the silicon single crystal characterized by being controlled so that it may exist.

  Further, according to the present invention, in the strength distribution in the pulling axis direction of the rotating magnetic field at the interface between the inner wall of the crucible and the silicon melt, the region where the strength is 100 to 50% is 0.5H from the surface of the silicon melt. It is controlled so that it exists within the range.

  According to the present invention, the rotating magnetic field is a plurality of rotating magnetic fields having at least different rotating frequencies among a rotating direction, a rotating frequency, and a magnetic field strength in a plane perpendicular to the pulling direction of the silicon single crystal. The present invention relates to the manufacturing method.

  Further, in the present invention, the rotation direction of the crucible and the silicon single crystal is opposite to the rotation direction of the rotating magnetic field, the rotation speed of the crucible is 1 to 12 rpm, and the rotation speed of the silicon single crystal Is about 0.1-20 rpm, it is related with the said manufacturing method characterized by the above-mentioned.

  According to the manufacturing apparatus and the manufacturing method of the present invention, it is possible to pull up the silicon single crystal at a high speed while making the impurity distribution in the grown silicon single crystal uniform, compared to the conventional manufacturing method that does not use a rotating magnetic field. it can.

  In addition, according to the manufacturing apparatus and the manufacturing method of the present invention, it is not necessary to apply a uniform magnetic field to the entire melt in order to create an optimum melt convection for achieving the above-described effects. Even when applied to a large growth furnace for growing silicon single crystals, the rotating magnetic field apparatus can be made low-cost and simple.

  Hereinafter, the present invention will be described in detail according to embodiments.

  The feature of the silicon single crystal manufacturing apparatus and the manufacturing method of the present invention is that the above-described configuration realizes a melt flow arranged to make the impurity distribution in the grown silicon single crystal uniform, This enables high-speed pulling of a silicon single crystal.

  Here, the silicon single crystal production apparatus and production method of the present invention can be applied to the production of various single crystal ingots, that is, the size (weight, diameter, etc.) of the target single crystal ingot. There is no particular limitation, and it can be selected as appropriate depending on the type of silicon wafer required, etc., but is particularly suitable for manufacturing large-diameter single crystal ingots from the viewpoint that the rotating magnetic field apparatus can be reduced in size. It is. Moreover, there is no restriction | limiting in particular also about the presence or absence of dope of various elements, According to the performance etc. of the required silicon wafer, it can dope suitably.

  The feature of the present invention is that the position where the magnetic field applied by the rotating magnetic field has the maximum intensity in the melt is controlled so as to exist in the vicinity of the surface of the melt.

  Here, the strength of the magnetic field generated from a general rotating magnetic field device is not uniform in the direction of the pulling-up axis, and the position where the magnetic field generated by the rotating magnetic field device has the maximum strength is approximately the position of the core of the rotating magnetic field device. The same is true for the position where the magnetic field in the melt reaches the maximum intensity in line with the center position in the pulling-up axis direction. Therefore, by adjusting the relative position of the crucible and the rotating magnetic field device based on the position of the melt surface and the center position of the rotating magnetic field device, the position of the approximate maximum intensity in the melt can be adjusted. is there. Furthermore, for detailed magnetic field distribution, commercially available general-purpose magnetic field analysis software (for example, ANYSYS manufactured by ANYSYS Inc., JMAG manufactured by Japan Research Institute, Maxwell 3D manufactured by ANSOFT, ELF / MAGIC manufactured by Elf, etc.) is used. Therefore, it is possible to calculate with high accuracy.

  In order to create a uniform melt flow that makes the single crystal impurity distribution uniform and a temperature distribution that enables high-speed pulling, the position where the magnetic field generated by the rotating magnetic field device has the maximum intensity in the melt is melted. What is necessary is just to exist within the depth of 0.3H from the surface of a liquid. On the other hand, when the same apparatus is used and the same rotating magnetic field is applied, the effect obtained when the position where the maximum intensity is at a position deeper than 0.3H from the surface is within 0.3H (arranged) It is difficult to obtain a melt flow). Therefore, if the same effect is to be obtained, the strength of the magnetic field needs to be increased, resulting in increased waste. In consideration of the effective use of the magnetic field throughout the single crystal growth process, it is preferable that the position where the maximum strength is always present within the depth of 0.3H during the formation of the straight body portion.

  In the present invention, the position where the magnetic field generated by the rotating magnetic field device has the maximum intensity in the melt is within a depth of 0.3 H from the surface of the melt, and the inner wall of the crucible and the silicon melt In the strength distribution in the pulling-up axis direction of the rotating magnetic field at the interface, it is preferable that a region where the strength is 100 to 50% exists within a depth of 0.5 H from the surface of the silicon melt. In this way, most of the magnetic field applied in the melt exists in the vicinity of the surface, and more efficient use of the magnetic field (a well-equipped melt flow and a temperature distribution suitable for high-speed pulling up) can be performed. Also in this case, it is more preferable from the viewpoint of effective use of the magnetic field that the region where the strength is 100% to 50% is always controlled during the formation of the single crystal straight body portion. .

In the present invention, it is preferable to use a rotating magnetic field apparatus having a depth of silicon melt at the start of pulling of H ₀ and a core pulling axis width of 0.3 H ₀ or less. The size of the core of the rotating magnetic field device depends on the maximum intensity of the magnetic field that can be generated by the rotating magnetic field device. In order to obtain an effect (melt flow) comparable to that obtained by a conventional rotating magnetic field apparatus having a width equivalent to the height of the crucible by the present invention, this width is sufficient. Accordingly, the present invention is advantageous in terms of cost and convenience of the rotating magnetic field device.

  The shape of the crucible used in the production apparatus and production method of the present invention is not particularly limited, and any crucible may be used as long as it is used for a general silicon single crystal growth apparatus. Most commonly, the diameter of the crucible is about 2 to 3 times and the depth is about 0.2 to 2 times the diameter of the single crystal ingot to be grown.

  There is no particular limitation on the amount of melt at the start of pulling. Generally, a melt of about 1.1 to 1.2 times the weight of the target silicon single crystal ingot is stored in a crucible.

  Moreover, there is no restriction | limiting in particular also about the control method of the relative position of a crucible, a rotating magnetic field, and a raising axis direction. For example, it is possible to fix the rotating magnetic field and move only the crucible up and down, to fix the height of the crucible and raise and lower the rotating magnetic field height, or to control both heights up and down . In a general growing device, a crucible lifting mechanism is provided, and in addition to this, if a lifting mechanism for a rotating magnetic field device is provided, both heights can be raised and lowered. Further, it is necessary to grasp the surface position of the melt that changes as the single crystal grows, but there is no particular limitation on the method at this time. For example, the surface position can be obtained by obtaining the depth from the weight of the single crystal or the melt being pulled, or measuring the melt surface position by installing a liquid level sensor in the growth furnace. Done.

  Moreover, there is no restriction | limiting in particular also about the rotating magnetic field apparatus used for the manufacturing apparatus and manufacturing method of this invention, The rotating magnetic field apparatus of the same structure as the rotating magnetic field apparatus normally used for an electromagnetic motor etc. can be used preferably. It is also possible to create a more precise melt convection and temperature distribution using a multi-frequency magnetic field device.

Furthermore, there are no particular restrictions on the growth conditions of the silicon single crystal when applying the production apparatus and production method of the present invention, but preferably the strength of the rotating magnetic field force applied to the melt calculated by the general-purpose magnetic field analysis software 0.1 to 10 N / m ³ , the rotation frequency is 10 Hz to 200 Hz, the direction of rotation of the crucible and the single crystal is opposite to the direction of the rotating magnetic field, the rotation speed of the crucible is 1 rpm to 12 rpm, and the silicon single crystal The rotation speed is in the range of 0.1 rpm to 20 rpm. If the generated rotating magnetic field force is smaller than the required range, the flow of the melt due to thermal convection cannot be changed, and if it exceeds this range, an extremely fast flow can be generated in the melt. It is not preferable because it swells. Moreover, if the frequency of the rotating magnetic field is smaller than the range, it is difficult to control the current voltage, which is not practical. On the other hand, if it is larger than this range, the magnetic field hardly penetrates into the melt and the effect may be reduced. As described above, the upward flow that flows along the crucible is generated by the difference between the rotation of the melt created by the rotating magnetic field and the rotation of the crucible, so that the crucible and the rotating magnetic field are preferably in opposite directions. In addition, by making the rotation of the crystal opposite to the direction of the rotating magnetic field, it is possible to create a place where the flow of the melt changes greatly in the vicinity of the crystal, thereby creating a steeper temperature gradient near the crystal and raising it at high speed. Will be possible. The number of revolutions of the crucible and the silicon single crystal is a range that is used under normal conditions in which no rotating magnetic field is used.

  Hereinafter, the present invention will be described in more detail with reference to the drawings, but the present invention is not limited thereto.

(Example 1)
As a preliminary study, we investigated the difference in the effect on the melt flow between a rotating magnetic field uniform in the direction of the pulling axis and a magnetic field localized on the melt surface. That is, when a crystal having a diameter of 300 mm in a 28-inch diameter crucible (711 mm) was pulled up from a melt having a height of 150 mm from the bottom of the crucible to the surface of the melt, a rotating magnetic field was applied to the entire melt and in the vicinity of the surface. The difference in time was examined by two-dimensional numerical simulation.

  FIG. 1 shows the distribution of the applied rotating magnetic field in the pulling axis direction at the crucible end.

  FIG. 1 shows three magnetic field distributions. That is, a magnetic field having a uniform predetermined intensity in the depth direction (the same intensity as the maximum intensity described later), the maximum intensity on the outermost surface, and the position where the intensity is 50% of the maximum intensity is 10 mm (0.07H) from the surface. And a magnetic field distribution where the maximum intensity is 5 mm (0.03H) from the surface and the position where the intensity is 50% of the maximum intensity is 15 mm (0.1H).

FIG. 2 is a diagram showing the melt flow when the crystal rotation is 10 rpm, the crucible rotation is 6 rpm, the crystal rotation and the crucible rotation are in the same direction, and the rotation of the rotating magnetic field is in the opposite direction. It can be seen that a flow equivalent to the case where a uniform magnetic field is applied to the entire melt (FIG. 2A) is formed in any magnetic field localized on the surface. (Fig. 2B, C)
From this, in the present invention, it is predicted that by applying a magnetic field near the surface, the impurity distribution becomes uniform as when a uniform magnetic field is applied to the melt.

Next, detailed numerical simulation was performed under the following conditions to investigate the effect of the present invention. The crystal diameter is 300 mm and the crucible diameter is 28 inches (711 mm). The amount of raw material polycrystalline silicon is 350 kg, and the height of the melt surface when the melt is melted is 420 mm from the bottom of the crucible. The thickness of the core of the rotating magnetic field generator in the pulling-up axis direction is 100 mm, the inner diameter of the core is 1200 mm, and the outer diameter is 1800 mm. The core was installed so that the upper end of the core was at the same level as the melt surface. At this time, the position where the magnetic field in the melt is maximized is at the same level as the center of the core, and is 50 mm from the melt surface. Further, the position where the magnetic field strength is 50% of the maximum strength is 200 mm from the melt surface as a result of calculation including the influence of the chamber of the pulling machine. The rotation of the crucible is 4 rpm, the rotation of the crystal is 6 rpm in the same direction as the crucible, and a rotating magnetic field of 25 Hz is applied in the opposite direction to the rotation of the crucible, and the force in the rotation direction induced by the melt is 6 N / m ^{3 at the} maximum. The current was adjusted as follows.

  Under these conditions, a three-dimensional melt flow analysis was performed. The software used was a CG-SIM manufactured by Semiconductor Technology Research, and calculations were performed in consideration of the fluctuation of the solid-liquid interface due to the solidification of crystals and the influence of the gas flowing in the pulling machine. FIG. 3 shows the result of viewing the melt flow in a longitudinal section, and FIG. 4 shows the result seen from above. A very well-organized flow can be created throughout the crucible. FIG. 5 shows the temperature gradient distribution from the end of the ingot to the crucible wall on the melt surface. When a rotating magnetic field is used, as shown in FIG. 4, a stable flow is drawn from the crucible wall to the lower part of the ingot, so that a high temperature gradient is obtained at the end of the ingot. It is considered that crystal growth is possible.

  On the other hand, when a rotating magnetic field is not used, the flow is complicated as shown in FIG. 6 and the temperature gradient at the crystal edge is small, so that the crystal growth is not uniform and the speed is low. It was.

(Example 2)
Next, an example is shown regarding the manufacturing apparatus concerning this invention. FIG. 7 is a schematic view showing an example of an apparatus for producing a silicon single crystal according to the present invention. FIG. 8 is a perspective view conceptually showing the positional relationship and structure between the quartz crucible 4a and the rotating magnetic field device 6 in the manufacturing apparatus 1 shown in FIG. Further, FIG. 9 is a schematic view showing the relationship between the shape of a general crucible and the melt depth H.

  The manufacturing apparatus 1 includes a pulling furnace 2, a crucible support shaft 3 provided through the center of the bottom of the pulling furnace 2, a graphite crucible 4 b held at the upper end of the crucible support shaft 3, and a graphite crucible The quartz crucible 4a loaded in 4b, the heater 5 arranged in the pulling furnace 2 to heat the crucibles 4a, 4b and their surroundings from the surroundings, and the crucibles 4a, 4b (4a, 4b together) 4) and a rotating magnetic field device 6 provided outside the pulling furnace 2 so as to surround the heater 5 concentrically, a crucible support shaft drive mechanism 7 for moving the crucible support shaft 3 up and down, and a seed crystal 8 A holding seed chuck 9, a pulling wire 10 that supports the seed chuck 9, a wire winding / unwinding mechanism 11, a rotating magnetic field device lifting / lowering mechanism (not shown), and a control device 13 are provided. The control device 13 controls operations of the rotating magnetic field device 6, the crucible support shaft driving mechanism 7, the wire winding / unwinding mechanism 11, the rotating magnetic field device lifting / lowering mechanism, the heater power supply (not shown), and the gas supply / discharge mechanism.

  When a single crystal rod is grown using the manufacturing apparatus 1, the seed crystal 8 attached to the tip of the seed chuck 9 at the tip of the pulling wire 10 is wound by the wire winding / unwinding mechanism 11. The tip is brought into contact with the raw material melt 15, and then the wire 10 is gently wound while rotating the seed crystal 9 and the crucible 4 filled with the raw material melt, so that a single crystal is formed below the seed crystal. 12 is formed.

In the manufacturing apparatus 1, as shown in FIG. 8, when the melt depth is H, the center position of the core of the rotating magnetic field apparatus 6 is 0.1 H from the melt surface. The height of the crucible 4 is controlled by the control device 13. In other words, pulling at the start, as H ₀ the depth of the melt at the pulling start, the center of the core of the rotating field apparatus 6 and the crucible 4 to be positioned from the melt surface 0.1H ₀ rotational magnetic field apparatus 6 Is adjusted by the control device 13.

As the growth of the single crystal ingot proceeds, the surface of the melt decreases. For example, it is assumed that the position of the center of the core of the rotating magnetic field device 6 becomes 0.08H _{0 from} the surface of the melt by reducing the surface of the melt by 0.02H ₀ . At this time, in the manufacturing apparatus 1, the crucible 4 is raised by 0.02H ₀ in order to keep the melt surface at a certain position. Further, since the melt depth H at this time is 0.98H ₀ , the rotating magnetic field device 6 is 0 so that the position of the core center is 0.098H ₀ (= 0.1H) from the melt surface. Ascending by .002H ₀ . In this way, in this manufacturing apparatus 1, during the growth of a single crystal, particularly during the formation of the straight body portion, the maximum intensity position in the melt of the magnetic field applied by the rotating magnetic field apparatus 6 is always 0.1H. The heights of the crucible 4 and the rotating magnetic field device 6 are controlled. For this reason, the rotating magnetic field can be effectively used. In this example, the ratio between the melt depth H and the core center position of the rotating magnetic field device 6 is set to be always 0.1, but this value should be varied within 0.3. Also good.

  Next, the rotating magnetic field apparatus 6 used in the apparatus described above will be described. FIG. 10 is a configuration diagram illustrating the structure of the rotating magnetic field device.

The rotating magnetic field device 6 is arranged concentrically so as to surround the crucible 4. As shown in FIG. 7, the rotating magnetic field device 6 has a substantially cylindrical electromagnet core 21, and 24 slots radially extending toward the outer peripheral surface are formed on the inner peripheral surface of the core 21 at equal pitches in the circumferential direction. Has been. The core 21 is formed by laminating thin electromagnetic steel plates having a flat ring shape with internal teeth. A substantially ring-shaped copper winding core 22 having a vertical “U” shape is attached to the outer peripheral edge of the core 21, and the electric coils C <b> 1 to C <b> 24 are guided to the slots of the core 21 and further wound. The outer surface of the core 22 is wound around and wound around the core 21. (Coil No. is from C1 to C24 in the clockwise direction.) The core 21, the winding core 22, and the electric coils C1 to C24 are covered with a stainless steel cover 23. The teeth between the slots of the core 21 are magnetic poles, and the end faces thereof are opposed to the outer peripheral surface of the quartz crucible 4a through the furnace wall and the graphite crucible 4b. In this example, the width of the pulling axis direction of the core is designed to be 0.2 H _0.

  In each of the electric coils C1 to C24, a high frequency power supply circuit 25 (hereinafter referred to as a power supply circuit 25) that generates a three-phase AC voltage having a predetermined frequency is connected via power supply terminals TU to TW.

  The power supply circuit 25 is connected to the control circuit 26. The control circuit 26 gives a frequency command value F corresponding to the frequency command value f input from the control device 13 and a coil voltage command value Vdc corresponding to the command current value i to the power circuit 25. The power circuit 25 A three-phase AC voltage having a frequency indicated by the value F is applied to the electric coils C1 to C24 through power supply terminals TU to TW at a voltage value corresponding to the coil voltage command value Vdc.

  In this way, a magnetic field having a predetermined frequency and a predetermined intensity rotating in a plane perpendicular to the single crystal pulling axis direction is applied to the melt.

  In the above description, one control device 13 controls all the operations of the rotating magnetic field device 6, the crucible support shaft drive mechanism 7, the wire winding function 11, the heater power supply, and the gas supply / discharge mechanism. However, it goes without saying that a control device may be provided for each control target.

  Further, the structure, the number of slots, the number of coils, the control method, and the like of the rotating magnetic field device 6 are not limited to the configuration of this embodiment.

FIG. 1 is a diagram showing the distribution of the applied rotating magnetic field in the pulling axis direction from the crucible end in the present invention. In FIG. 1, the solid line has the maximum intensity on the outermost surface, and the position where 50% of the maximum intensity is 10 mm (0.07 H) from the surface, and the alternate long and short dash line has the maximum intensity of 5 mm (0. The distribution of the magnetic field is such that the position where the maximum intensity is 50% and the depth where the maximum intensity is 50% is 15 mm (0.1 H). A broken line indicates a distribution of a magnetic field having a predetermined intensity that is uniform in the depth direction. FIG. 2 is a diagram showing the melt flow in the present invention when the crystal rotation is 10 rpm, the crucible rotation is 6 rpm, the crystal rotation and the crucible rotation are in the same direction, and the rotation of the rotating magnetic field is in the opposite direction (center of the crucible). FIG. 2A shows a case where the magnetic field indicated by the broken line in FIG. 1B is applied, FIG. 2B shows a case where the magnetic field indicated by the solid line in FIG. 1B is applied, and FIG. 2C shows a case where the magnetic field indicated by the one-dot chain line in FIG. FIG. 3 is a diagram (cross-sectional view) showing the result of detailed simulation of the melt flow in the present invention. FIG. 4 is a view of the melt flow of FIG. 3 as viewed from above. FIG. 5 shows the temperature gradient distribution from the end of the ingot to the crucible wall on the melt surface. In the figure, T represents temperature (K), and R represents radial length (cm). Further, ● represents a case where no rotating magnetic field (RMF) was applied, and ○ represents a case where a rotating magnetic field was applied near the surface. FIG. 6 is a diagram (cross-sectional view) showing a melt flow when a rotating magnetic field is not applied as a comparative example. FIG. 7 is a schematic view showing an example of an apparatus for producing a silicon single crystal according to the present invention. FIG. 8 is a perspective view conceptually showing the positional relationship and structure between the quartz crucible 4a and the rotating magnetic field device 6 in the manufacturing apparatus 1 shown in FIG. FIG. 9 is a diagram for explaining a general crucible shape and melt depth. FIG. 10 is a configuration diagram illustrating the structure of the rotating magnetic field device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Silicon single crystal manufacturing apparatus 2 Growth furnace 3 Crucible support shaft 4 Crucible 4a Quartz crucible 4b Graphite crucible 5 Heater 6 Rotating magnetic field device 7 Crucible support shaft drive mechanism 8 Seed crystal 9 Seed chuck 10 Pulling wire 11 Wire unwinding and unwinding mechanism 12 Silicon Single crystal ingot 13 Controller 15 Silicon melt 21 Electromagnetic core 22 Winding core 23 Stainless steel cover 25 Power supply circuit 26 Control circuit C Coil H Melt depth

Claims (8)

In an apparatus for producing a silicon single crystal by the Czochralski method,
A crucible containing a silicon melt;
A rotating magnetic field device that applies a rotating magnetic field that rotates in a plane perpendicular to the pulling direction of the silicon single crystal;
In order to make the position where the magnetic field generated by the rotating magnetic field device has the maximum intensity in the silicon melt within a depth of 0.3 H from the surface of the melt when the depth of the silicon melt is H, An apparatus for producing a silicon single crystal, comprising: the rotating magnetic field device; and a control device for adjusting a relative position of the crucible in the pulling-up axis direction.   In the intensity distribution in the pulling-axis direction of the rotating magnetic field at the interface between the inner wall of the crucible and the silicon melt, the control device has a depth of 0 to 50% from the surface of the silicon melt. The manufacturing apparatus according to claim 1, wherein the relative position of the rotating magnetic field device and the crucible in the pulling axis direction is adjusted so as to exist within 5 H. The width of the pulling axis direction of the core of the rotating magnetic field device, the depth of the silicon melt during pulling start as H _0, and the 0.3H ₀ or less, and, from the position of the center of the core melt surface The manufacturing apparatus according to claim 1, wherein the manufacturing apparatus is within a depth of 0.3H.   The rotation magnetic field is a plurality of rotation magnetic fields having at least different rotation frequencies among a rotation direction, a rotation frequency, and a magnetic field intensity in a plane perpendicular to a pulling direction of the silicon single crystal. The manufacturing apparatus in any one of 1-3. In the method for producing a silicon single crystal by the Czochralski method,
Pulling up the single crystal while applying a rotating magnetic field that rotates in a plane perpendicular to the pulling direction of the silicon single crystal to the silicon melt contained in the crucible,
When the depth of the silicon melt is H, the position where the magnetic field generated by the rotating magnetic field device has the maximum intensity in the silicon melt is controlled to be within a depth of 0.3 H from the melt surface. A method for producing a silicon single crystal, wherein:   In the intensity distribution in the axial direction of the rotating magnetic field at the interface between the inner wall of the crucible and the silicon melt, a region where the intensity is 100% to 50% is present within 0.5 H from the surface of the silicon melt. The manufacturing method according to claim 5, wherein the manufacturing method is controlled by:   The rotation magnetic field is a plurality of rotation magnetic fields having at least different rotation frequencies among a rotation direction, a rotation frequency, and a magnetic field intensity in a plane perpendicular to a pulling direction of the silicon single crystal. The manufacturing method of 5 or 6. The direction of rotation of the crucible and the silicon single crystal is opposite to the direction of rotation of the rotating magnetic field;
The rotational speed of the crucible is 1 rpm to 12 rpm,
And the rotational speed of the said silicon single crystal is 0.1 rpm-20 rpm, The manufacturing method in any one of Claims 5-7 characterized by the above-mentioned.