JP2012041246A - Thin plate-manufacturing apparatus, thin plate-manufacturing method, and crucible - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin plate-manufacturing apparatus and a thin plate-manufacturing method, which can control plate thickness by preventing the thickness irregularity of a thin plate from occurring, in the thin plate-manufacturing apparatus and the thin plate-manufacturing method for manufacturing the thin plate on a surface of a backing plate by immersing the backing plate in a material melt; and to provide a crucible.SOLUTION: The thin plate-manufacturing apparatus manufactures the thin plate on the surface of the backing plate by immersing the backing plate into the material melt. The thin plate-manufacturing apparatus includes: the crucible, the inside of which can be filled with the material melt; and an immersing unit for immersing the backing plate in the material melt in the crucible. The crucible includes; a crucible body; and a controlling unit for controlling the direction to which the material melt on the surface flows according to a direction in which the backing plate is immersed.

Description

  The present invention relates to a thin plate manufacturing apparatus for manufacturing a thin plate on the surface of a base plate by immersing the base plate in a raw material melt, a thin plate manufacturing method using the same, and a crucible. More specifically, the present invention relates to a thin plate manufacturing apparatus, a thin plate manufacturing method using the same, and a crucible for controlling the direction of the liquid flow on the surface of the raw material melt in accordance with the dipping direction of the base plate.

  Conventionally, a polycrystalline silicon thin plate is produced by gradually cooling the silicon melt contained in the mold over time, cutting the resulting polycrystalline ingot into blocks, and then slicing the blocks. The increase in cost due to slicing and the loss of silicon were significant.

  As a method for solving such a problem and producing a thin plate of polycrystalline silicon in large quantities at low cost, a method that does not require a slicing step is known.

  Patent Document 1 (Japanese Patent Application Laid-Open No. 2006-182626) discloses a method for producing a plate-like crystal in which a raw material is heated and melted in a crucible and a crystal of the raw material is solidified and grown on a substrate. In this manufacturing method, a plurality of movable heat insulating means are provided on the edge of the crucible opening so that the temperature distribution in the horizontal direction of the molten raw material is uniformed, the silicon growth unevenness in the substrate, and the crucible wall It suppresses the solidification of silicon.

  Patent Document 2 (Japanese Patent Application Laid-Open No. 2008-159781) discloses a solid phase in which a semiconductor material melt is accommodated in a crucible and a substrate is immersed in the semiconductor material melt to produce a solid sheet on the surface of the substrate. A sheet manufacturing method is disclosed. In this manufacturing method, the growth of solidification generated from the vicinity of the boundary between the semiconductor melt and the inner wall of the crucible is suppressed by providing a radiation reflecting plate in contact with both the upper surface of the crucible and the outer surface of the crucible.

JP 2006-182626 A JP 2008-159781 A

  The present inventors have found a problem that when a thin plate is manufactured using the methods described in Patent Document 1 and Patent Document 2, unevenness occurs in the thickness of the thin plate and the plate thickness becomes unstable. When the cause was examined, it was found that the disturbance of the liquid flow on the surface of the melt was one factor.

  In the thin plate manufacturing method described in Patent Document 1, since the temperature distribution of the melt is substantially uniform, for example, when the melt such as silicon nitride solidifies in the vicinity of the crucible wall, the temperature balance of the melt is lost and the melt is melted. Therefore, it is considered that the thickness of the thin plate is uneven. Further, when unevenness occurs in the thin plate, there is a problem that the yield of the thin plate manufacturing is deteriorated.

  An object of the present invention is to control the plate thickness by preventing the occurrence of uneven thickness of the thin plate in the thin plate manufacturing apparatus and manufacturing method for manufacturing the thin plate on the surface of the base plate by immersing the base plate in the raw material melt. An object of the present invention is to provide a thin plate manufacturing apparatus, a thin plate manufacturing method, and a crucible.

  The present invention is a thin plate manufacturing apparatus for manufacturing a thin plate on the surface of a base plate by immersing the base plate in the raw material melt, and a crucible capable of filling the raw material melt therein, and the raw material melt in the crucible A dipping unit for dipping the base plate. The crucible includes a crucible body and a control unit that controls the direction of the liquid flow on the surface of the raw material melt in accordance with the immersion direction of the base plate.

  Preferably, in the thin plate manufacturing apparatus according to the present invention, the control unit controls the liquid flow direction on the surface of the raw material melt to be perpendicular to the immersion direction of the base plate projected in parallel to the surface of the raw material melt. To do.

  Preferably, in the thin plate manufacturing apparatus according to the present invention, the control unit controls the direction of the liquid flow on the surface of the raw material melt to be parallel to the immersion direction of the base plate projected in parallel to the surface of the raw material melt. To do.

  Preferably, in the thin plate manufacturing apparatus according to the present invention, the control unit is configured so that the direction of the liquid flow on the surface of the raw material melt is the same as the immersion direction of the base plate projected in parallel to the surface of the raw material melt. Control.

  In the thin plate manufacturing apparatus according to the present invention, the control unit preferably controls the direction of the liquid flow on the surface of the raw material melt by controlling the temperature distribution on the surface of the raw material melt.

  Preferably, in the thin plate manufacturing apparatus according to the present invention, the control unit is configured such that the temperature of the surface of the raw material melt at the position where the base plate enters the raw material melt is the temperature of the raw material melt at the position where the base plate escapes from the raw material melt. The temperature distribution on the surface of the raw material melt is controlled to be higher than the surface temperature.

  Preferably, in the thin plate manufacturing apparatus according to the present invention, the control unit includes a heat insulating unit, the heat insulating unit exposes the raw material melt to the outside of the crucible, and an opening provided at the upper part of the crucible main body, and the crucible main body It is installed in contact with one of the outer walls, and the direction of the liquid flow on the surface of the raw material melt is controlled by the heat insulating part.

  Preferably, in the thin plate manufacturing apparatus according to the present invention, the shape of the opening is axisymmetric, and the heat insulating part is installed asymmetrically with respect to any symmetry axis of the opening projected in parallel to the surface of the raw material melt. .

  Preferably, in the thin plate manufacturing apparatus according to the present invention, the control unit includes a baffle plate installed inside the crucible body, and controls the direction of the liquid flow on the surface of the raw material melt by the baffle plate.

  Preferably, in the thin plate manufacturing apparatus according to the present invention, the baffle plate is an opening provided in the upper part of the crucible body that exposes the raw material melt to the outside of the crucible and has an axisymmetric shape. It is installed asymmetrically with respect to any axis of symmetry projected in parallel on the surface of the raw material melt.

  Preferably, in the thin plate manufacturing apparatus according to the present invention, the control unit includes a heat insulating unit and a baffle plate for controlling the direction of the liquid flow on the surface of the raw material melt, and the heat insulating unit exposes the raw material melt to the outside of the crucible. The baffle plate is installed in contact with either the opening provided in the upper part of the crucible main body or the outer wall of the crucible main body, and the baffle plate is installed in the crucible main body, and the heat insulating portion and the baffle plate are generated by the heat insulating portion. It is installed so that the direction of the liquid flow on the surface of the raw material melt is parallel to the direction of the liquid flow on the surface of the raw material melt generated by the baffle plate.

  Preferably, in the thin plate manufacturing apparatus according to the present invention, the crucible main body includes a substantially rectangular opening for exposing the raw material melt to the outside of the crucible, and the control unit is in contact with at least three sides of the substantially rectangular opening. A heat insulating portion installed to cover the upper part of the raw material melt, and a first baffle plate, a second baffle plate, and a third baffle plate installed substantially perpendicular to the bottom surface of the crucible inside the crucible, And the first baffle plate and the second baffle plate are opposed to each other and parallel to each other, and the third baffle plate is formed of the first baffle plate. One end is connected to one end of the second baffle plate and is perpendicular to the first and second baffle plates.

  This invention is a thin plate manufacturing method using said thin plate manufacturing apparatus, Comprising: The following processes are provided. A raw material melt is obtained by heating the raw material in a crucible. The base plate is immersed in the raw material melt. The direction of the liquid flow on the surface of the raw material melt is controlled according to the immersion direction of the base plate in the step of immersing the base plate.

  The present invention is a crucible that can be filled with a raw material melt, and the crucible includes a crucible body and a control unit, and the crucible body has a line-symmetric opening that exposes the raw material melt to the outside of the crucible. The control unit is in contact with the crucible main body and is set asymmetrically with respect to any symmetry axis of the opening projected in parallel on the surface of the raw material melt.

  According to the present invention, it is possible to obtain a thin plate manufacturing apparatus, a thin plate manufacturing method, and a crucible that can prevent the occurrence of uneven thickness of the thin plate and control the plate thickness.

It is the schematic which shows the structure of the thin plate manufacturing apparatus in one embodiment of this invention. It is a top view of a crucible body. It is sectional drawing of the thin plate produced on the baseplate surface. It is a figure which shows an example of the baseplate in one embodiment of this invention. It is a top view of the crucible main body in which the heat insulation part was installed. It is a top view of the crucible main body in which the baffle plate was installed. It is a figure which shows the example of arrangement | positioning of a heat insulation part and a baffle plate. 4 is a top view of a crucible used in Production Example 1. FIG. 9A is a top view of the crucible used in Production Example 2, FIG. 9B is a cross-sectional view of the crucible, and FIG. 9C is a cross-sectional view of the thin plate obtained. 10A is a top view of the crucible used in Production Example 3, FIG. 10B is a cross-sectional view of the crucible, and FIG. 10C is a cross-sectional view of the thin plate obtained. 11A is a top view of the crucible used in Production Example 4, FIG. 11B is a cross-sectional view of the crucible, and FIG. 11C is a cross-sectional view of the thin plate obtained.

<Thin plate manufacturing equipment>
A thin plate manufacturing apparatus according to an embodiment of the present invention is a thin plate manufacturing apparatus that manufactures a thin plate on the surface of a base plate by immersing the base plate in the raw material melt, and is a crucible that can be filled with the raw material melt. And an immersion part for immersing the base plate in the raw material melt in the crucible. The crucible includes a crucible body and a control unit that controls the direction of liquid flow on the surface of the raw material melt in accordance with the immersion direction of the base plate. By controlling the direction of the liquid flow on the surface of the raw material melt, unevenness of the thickness of the thin plate can be prevented and the thickness can be controlled.

  As the raw material melt, a melt of a substance containing at least one of a metal and a semiconductor can be used. Since the melt is a conductive fluid, a liquid flow can be generated in the raw material melt by applying an electromagnetic field. Further, even when a temperature difference exists in the fluid made of the melt, a liquid flow is generated according to the temperature distribution. Therefore, in one embodiment of the present invention, the direction of the liquid flow on the surface of the raw material melt can be controlled by applying an electromagnetic field, temperature distribution in the fluid, or the like. The method using the temperature distribution in the fluid is preferable to the method of applying the electromagnetic field because the equipment of the thin plate manufacturing apparatus can be simplified.

  Hereinafter, a thin plate manufacturing apparatus that controls the direction of the liquid flow on the surface of the raw material melt by controlling the temperature distribution in the fluid will be specifically described as an example. The direction control method is not limited to the method using the temperature distribution.

(Embodiment 1)
A thin plate manufacturing apparatus according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic view showing the structure of a thin plate manufacturing apparatus according to an embodiment of the present invention. As shown in FIG. 1, the thin plate manufacturing apparatus 100 includes a crucible including a crucible body 101, a heat insulating unit 105, and a baffle plate 106, and an immersion unit 120. The crucible body 101 is filled with the raw material melt 102 melted by the heating unit 103. The dipping unit 120 has a function of immersing the base plate 104 in the raw material melt 102 to attach the raw material melt 102 to the surface of the base plate 104 and then removing the base plate 104 from the raw material melt 102. The raw material melt 102 adhering to the surface of the base plate 104 taken out is solidified and grown, and a thin plate is formed on the surface of the base plate 104.

  The crucible is arranged in a container (not shown) that can be decompressed. It is preferable that the depressurizable container has a mechanism that can be filled with an inert gas such as vacuum exhaust or argon gas so that a highly reactive raw material can be melted. Further, it is desirable that the depressurizable container is provided with an additional mechanism (not shown) for appropriately adding raw materials in the crucible in order to enable continuous thin plate production.

  The immersion unit 120 can be a guide rail, a rotating body, a robot arm, or the like. FIG. 1 shows a case where a guide rail is used. The guide rail includes a horizontal operation rail 110, a slide body 111 that operates along the horizontal operation rail 110, and an elevating mechanism 112 attached to the slide body. A suspension column 113, a rotation mechanism 114 installed on the suspension column 113, a rotation column 115 operated by the rotation mechanism 114, and a pedestal support 116 are suspended from the lifting mechanism 112. A pedestal 117 is connected to the pedestal support 116. A base plate 104 is detachably held on the pedestal 117.

  When the slide body 111 moves along the horizontal operation rail 110, the base plate 104 also moves in the horizontal direction. When the lifting mechanism 112 moves the suspension column 113 in the vertical direction, the base plate 104 also moves in the vertical direction. The rotation operation of the base plate 104 is performed by the rotation mechanism 114. The movement of the base plate 104 in the horizontal direction, the movement in the vertical direction, and the rotation can be independently controlled. The base plate 104 can be immersed in the raw material melt 102 by appropriately combining the movement of the base plate in the horizontal direction, the vertical movement, and the rotation operation. In the present specification, the immersion trajectory means a trajectory of at least a part of the base plate from the entry to the raw material melt after the base plate 104 moves.

  Furthermore, when the thin plate is continuously manufactured, the position of the surface of the raw material melt gradually decreases as the amount of the raw material melt decreases, so that the immersion part 120 adjusts the immersion track of the base plate 113 according to the position of the melt surface. It is desirable to have an adjustable function.

  The base plate 104 is a plate material made of high purity graphite or the like, and a thin plate is formed by the solidification and growth of the melt on at least the surface layer portion of the plate material.

  The shape of the crucible body 101 is not particularly limited as long as the raw material melt 102 can be held therein, but for example, as shown in FIG. 1, it is preferable to have a rectangular parallelepiped shape having an opening at the top.

  As the heating unit 103 used for melting the raw material, a general means capable of melting a metal raw material or a semiconductor raw material such as resistance heating, induction heating, or infrared heating can be used. In order to prevent the raw material melt 102 from solidifying inside the crucible main body 101, the heating unit 103 is preferably disposed at all or part of the periphery of the crucible 101.

In FIG. 1, the heat insulation part 105 and the baffle plate 106 are installed as a control part.
In the present embodiment, the heat insulating part 105 is installed so as to be in contact with the opening of the crucible body 101 and cover the vicinity of the interface between the inner wall of the crucible body 101 and the raw material melt 102. Since the heat insulating part 105 reflects the radiant heat from the raw material melt 102, by appropriately changing the arrangement, size, material, etc. of the heat insulating part 105, near the interface between the inner wall of the crucible body 101 and the raw material melt 102. The temperature of the raw material melt can be kept high. Furthermore, the heat insulating portion 105 can prevent impurities from being mixed into the raw material melt 102. Although FIG. 1 shows a mode in which the heat insulating portion 105 is installed only on the upper portion of the opening of the crucible main body 101, the heat insulating portion 105 may be further in contact with the outer wall of the crucible main body 101.

  The baffle plate 106 is installed inside the crucible body 101. When a raw material is heated and melted using a crucible, the crucible body temperature is generally high. Therefore, the temperature of the raw material melt near the interface between the inner wall of the crucible body 101 and the raw material melt 102 is also high. For this reason, by providing the baffle plate 106, the thermal diffusion of the raw material melt near the inner wall of the crucible body is reduced, and the temperature of the raw material melt between the baffle plate 106 and the inner wall of the crucible body 101 is kept high. Can do. The size of the baffle plate 106 is preferably adjusted so that the entire baffle plate 106 is immersed in the raw material melt 102. In this case, the surface area of the raw material melt 102 exposed to the outside of the crucible does not change, and the immersion track of the base plate 104 is not affected. Therefore, it is possible to obtain an immersion track similar to a crucible without the baffle plate 106 installed. On the other hand, when the heat insulating portion 105 is used, the immersion track of the base plate 104 becomes small. Therefore, in order to obtain the same immersion track as when the base plate is not installed, the size of the opening of the crucible body is set. It is necessary to increase the surface area of the raw material melt exposed to the outside.

  When the heat insulating part 105 or the baffle plate 106 is used, a temperature distribution can be generated on the surface of the raw material melt 102. The liquid flow on the surface of the raw material melt 102 has a directionality that flows from a higher temperature to a lower temperature. Therefore, by controlling the temperature distribution on the surface of the raw material melt 102, the direction of the liquid flow on the surface of the raw material melt 102 can be controlled. By controlling the direction of the liquid flow, the occurrence of uneven thickness of the thin plate can be prevented and the thickness can be controlled.

<Control unit>
(Relationship between the immersion direction of the base plate and the direction of the liquid flow on the surface of the raw material melt)
In one embodiment of the present invention, the control unit controls the direction of the liquid flow on the surface of the raw material melt according to the immersion direction of the base plate. Hereinafter, the relationship between the immersion direction of the base plate and the direction of the liquid flow on the surface of the raw material melt and the film thickness of the obtained thin plate will be described with reference to FIGS.

  2 (i) to 2 (iv) are top views of the crucible body 201 having a rectangular opening, and the raw material melt 202 is filled in the crucible body. An arrow S1 indicates the immersion direction of the base plate projected in parallel on the surface of the raw material melt 202. Arrow S2 indicates the direction of the liquid flow on the surface of the raw material melt 202.

  3 (i) to (iii) are cross-sectional views of a thin plate produced on the surface of the base plate in a direction perpendicular to the immersion direction S1 of the base plate.

  2 (i) and 2 (ii), the immersion direction S1 of the base plate and the direction S2 of the liquid flow on the surface of the raw material melt intersect perpendicularly. In this case, as shown in FIGS. 3 (i) and 3 (ii), a thin plate having a large film thickness difference in the direction perpendicular to the immersion direction S1 of the base plate is produced on the surface of the base plate. Further, for example, as shown in FIG. 4, when a base plate 404 having grooves parallel to the base plate immersion direction S1 is used, a plurality of thin plates having different average film thicknesses in a direction perpendicular to the base plate immersion direction S1. Can be manufactured at the same time. In the present specification, “vertical” does not mean an exact intersection at 90 °, but includes a deviation within 30 °, preferably within 15 ° from an intersection angle of 90 °.

  On the other hand, in FIG. 2 (iii) and FIG. 2 (iv), the immersion direction S1 of the base plate and the liquid flow direction S2 on the surface of the raw material melt are parallel. In this case, as shown in FIG. 3 (iii), a thin plate having a small film thickness difference in the direction perpendicular to the dipping direction S1 of the base plate is produced on the surface of the base plate. In particular, as shown in FIG. 2 (iii), when the relationship between the dipping direction S1 of the base plate and the direction S2 of the liquid flow on the surface of the raw material melt is parallel and the same direction, The film thickness difference in the vertical direction becomes very small. In this specification, “parallel” includes a deviation within 30 °, preferably within 15 ° from the parallel line. Furthermore, “parallel” includes both the case where the direction of the liquid flow on the surface of the raw material melt and the immersion direction of the base plate projected in parallel on the surface of the raw material melt of the base plate are the same and the case where they face each other. .

(Relationship between the arrangement of the control unit and the direction of liquid flow on the surface of the raw material melt)
In one embodiment of the present invention, the control unit controls the direction of the liquid flow on the surface of the raw material melt by controlling the temperature distribution on the surface of the raw material melt. The controller is not particularly limited as long as it can control the temperature distribution on the surface of the raw material melt. Hereinafter, from the viewpoint of ease of installation, the relationship between the arrangement of the control unit and the direction of the liquid flow on the surface of the raw material melt when at least one of the heat insulating unit and the baffle plate is used as the control unit is shown in FIG. This will be described with reference to FIGS.

First, the case where a heat insulating part is used as the control part will be described.
5A to 5I are top views of the crucible main body 501 whose opening is a rectangular parallelepiped shape, and the heat insulating portion 505 is open on the upper edge of the opening of the crucible main body 501. FIG. It is installed so as to cover the vicinity of the interface between the inner wall of the crucible body 501 and the raw material melt 502 in contact with the portion. A raw material melt 502 is filled in the crucible body. Although not shown in the figure, a heating unit is installed around the entire crucible. Since the heat insulation part 505 reflects the radiant heat from the raw material melt 502, the temperature of the raw material melt near the interface between the inner wall of the crucible body 501 and the raw material melt 502 can be kept higher than in other regions. As a result, a temperature distribution is formed on the surface of the raw material melt 502.

  For example, as shown in FIGS. 5 (a) to 5 (d), the heat insulating portion 505 is not projected with respect to the symmetry axes Sa to Sd parallel to the immersion direction S1 of the base plate projected in parallel to the surface of the raw material melt. By arrange | positioning so that it may become a contrast, the direction of the liquid flow of a raw material melt can be controlled so that it may become perpendicular | vertical with respect to the immersion method S1 of a base plate. The direction of the liquid flow on the surface of the raw material melt flows from a place having a high temperature to a place having a low temperature. Therefore, the relationship between the arrangement of the heat insulating portion 505 and the direction of the liquid flow on the surface of the raw material melt is the same as that of the surface of the raw material melt when the heat insulating portion is arranged as shown in FIGS. 5 (a) and 5 (c). The direction of the liquid flow is the direction indicated by S2 in FIG. 2 (i). When the heat insulating portion is arranged as shown in FIGS. 5 (b) and 5 (d), the direction of the liquid flow on the surface of the raw material melt Is in the direction indicated by S2 in FIG.

  On the other hand, as shown in FIGS. 5E to 5H, the heat insulating portion 505 is not projected with respect to the symmetry axis Se to Sh perpendicular to the immersion direction S1 of the base plate projected in parallel to the surface of the raw material melt. By arrange | positioning so that it may become a control | contrast, the direction of the liquid flow of a raw material melt can be controlled so that it may become parallel with respect to the immersion method S1 of a base plate. The direction of the liquid flow on the surface of the raw material melt flows from a place having a high temperature to a place having a low temperature. Therefore, the relationship between the arrangement of the heat insulating portion 405 and the direction of the liquid flow on the surface of the raw material melt is the same as that of the surface of the raw material melt when the heat insulating portion is arranged as shown in FIGS. 5 (e) and 5 (g). The direction of the liquid flow is the direction indicated by S2 in FIG. 2 (iii), and when the heat insulating portion is arranged as shown in FIG. 5 (f) and FIG. 5 (h), the direction of the liquid flow on the surface of the raw material melt Is the direction indicated by S2 in FIG.

Next, a case where a baffle plate is used as the control unit will be described.
6 (j) to 6 (m) are top views of the crucible main body 601 having a rectangular parallelepiped opening, and three baffle plates 606 are provided in the crucible main body 601 inside the crucible main body 601. It is installed so as to be parallel to three different wall surfaces. Further, one of the three baffle plates is disposed in contact with one side of each of the other two baffle plates in a direction perpendicular to the bottom surface of the crucible body 601. The crucible body is filled with a raw material melt 602. Although not shown in the figure, a heating unit is installed around the entire crucible. Since the crucible body 601 is heated by a heating unit installed around, the temperature of the raw material melt near the interface between the inner wall of the crucible main body 601 and the raw material melt 602 is higher than that of the raw material melt at other locations. It is hot. Since the baffle plate 606 inhibits the thermal diffusion of the surrounding raw material melt, the temperature of the raw material melt between the inner wall of the crucible body 601 and the baffle plate 606 can be kept high. As a result, a temperature distribution is formed on the surface of the raw material melt 602.

  For example, as shown in FIG. 6 (j) and FIG. 6 (k), the baffle plate 506 is not projected with respect to the symmetry axes Sj and Sk parallel to the immersion direction S1 of the base plate projected in parallel to the surface of the raw material melt. By arrange | positioning so that it may become a contrast, the direction of the liquid flow of a raw material melt can be controlled so that it may become perpendicular | vertical with respect to the immersion method S1 of a base plate. The direction of the liquid flow on the surface of the raw material melt flows from a place having a high temperature to a place having a low temperature. Accordingly, the relationship between the arrangement of the baffle plate 506 and the direction of the liquid flow on the surface of the raw material melt is as follows. When the baffle plate is arranged as shown in FIG. When the baffle plate is arranged as shown in FIG. 6 (k), the direction of the liquid flow on the surface of the raw material melt is the direction indicated by S2 in FIG. 2 (ii). It becomes.

  On the other hand, as shown in FIG. 6 (l) and FIG. 6 (m), the baffle plate 506 is not projected with respect to the symmetry axes S1 and Sm perpendicular to the immersion direction S1 of the base plate projected in parallel to the surface of the raw material melt. By arrange | positioning so that it may become a control | contrast, the direction of the liquid flow of a raw material melt can be controlled so that it may become parallel with respect to the immersion method S1 of a base plate. The direction of the liquid flow on the surface of the raw material melt flows from a place having a high temperature to a place having a low temperature. Therefore, the relationship between the arrangement of the baffle plate 506 and the direction of the liquid flow on the surface of the raw material melt is as follows. When the baffle plate is arranged as shown in FIG. When the baffle plate is arranged as shown in FIG. 6 (m), the direction of the liquid flow on the surface of the raw material melt is indicated by S2 in FIG. 2 (iv). Direction.

  Even if the heat insulating part and the baffle plate are used independently, the direction of the liquid flow on the surface of the raw material melt can be controlled, but by using a combination of the heat insulating part and the baffle plate, the surface of the raw material melt can be controlled. The flow of the liquid flow can be controlled more stably.

  When the heat insulating part and the baffle plate are used in combination, it is preferable that the flow directions of the raw material melt generated by the heat insulating part and the baffle plate are combined in the same direction.

  5 (a) or 5 (c), it is preferable to arrange the baffle plate in FIG. 6 (j), and in particular, FIG. 5 (c) and FIG. 6 (j) The combination of is more preferable. In this case, the direction of the liquid flow on the surface of the raw material melt is the direction indicated by S2 in FIG.

  When the arrangement of the heat insulating portions is FIG. 5 (b) or FIG. 5 (d), the arrangement of the baffle plates is preferably as shown in FIG. 6 (k), and in particular, FIG. 5 (d) and FIG. The combination of is more preferable. In this case, the direction of the liquid flow on the surface of the raw material melt is the direction indicated by S2 in FIG. 2 (ii).

  5 (e) or 5 (g), it is preferable to arrange the baffle plate in FIG. 6 (l), and in particular, FIG. 5 (g) and FIG. 6 (l) The combination of is more preferable. In this case, the direction of the liquid flow on the surface of the raw material melt is the direction indicated by S2 in FIG.

  5 (f) or 5 (h), it is preferable to arrange the baffle plate in FIG. 6 (m), and in particular, FIG. 5 (h) and FIG. 6 (m) The combination of is more preferable. In this case, the direction of the liquid flow on the surface of the raw material melt is the direction indicated by S2 in FIG.

  Further, as shown in FIG. 5 (i), the heat insulating part is installed on all four sides of the upper end of the opening, and the baffle plate is shown in any of FIGS. 6 (j) to 6 (m). It can also be arranged. In this case, the temperature of the raw material melt near the interface between the inner wall of the crucible body and the raw material melt can be kept higher by the heat insulating part than when the heat insulating part is not installed. Therefore, the temperature of the raw material melt between the inner wall of the crucible body and the baffle plate can be kept higher than when only the baffle plate is arranged. As a result, the temperature difference on the surface of the raw material melt becomes larger, and the direction of the liquid flow of the raw material melt can be controlled more stably.

  The heat insulating portion and the baffle plate are not limited to the shape, size, and arrangement shown in FIGS. 5 and 6, and the surface of the raw material melt is controlled to control the direction of the liquid flow on the surface of the raw material melt. Any shape, size and arrangement may be used as long as the temperature distribution can be controlled. For example, a heat insulating part or a baffle plate as shown in FIG. 7 can be used.

  The heat insulation part can be arranged like an eaves that touches the opening of the crucible body and covers the vicinity of the interface between the inner wall of the crucible body and the raw material melt, and also covers the outer wall in contact with the outer wall of the crucible body It can also be arranged.

<Crucible>
In one embodiment of the present invention, the crucible includes a crucible body and a control unit. The crucible body includes a line-symmetric opening that exposes the raw material melt to the outside of the crucible at the top, and the control unit is in contact with the crucible body, and any of the openings on the vertical projection surface of the crucible. It is installed asymmetrically with respect to the symmetry axis. The crucible body and the control unit can be the same as the thin plate manufacturing apparatus. When the crucible according to the present invention is used, the liquid flow on the surface of the raw material liquid can be controlled.

  When the heat insulating part and the baffle plate were used as the control part, the direction of the liquid flow on the surface of the raw material melt, the thickness of the obtained thin plate, and the state of the surface were confirmed.

  For the crucible body, a rectangular parallelepiped graphite container having a rectangular shape with an opening of 620 mm (short side) × 1005 mm (long side) was used.

  As the base plate, a graphite plate having a rectangular shape whose immersion surface is 215 mm (immersion direction) × 375 mm (perpendicular to the immersion direction) was used. In addition, a groove having a width of 5 mm was formed at a position parallel to the immersion direction of the base plate and the axis of symmetry of the base plate, so that two thin plates could be manufactured by one immersion. 1000 sheets were produced in each production example. Hereinafter, the thickness of the thin plate means an average value of the thickness of 1000 thin plates.

A silicon melt was used as the raw material melt.
Induction heating was used for the heating part, and it was arranged so as to surround the entire periphery of the crucible body.

CC material (carbon fiber reinforced carbon composite material) was used for the heat insulation part and the baffle plate.
The direction of the liquid flow on the surface of the raw material melt was confirmed by dropping the silicon raw material inside the crucible body and observing the floating state of the silicon raw material.

(Production Example 1)
A top view of the crucible used in Production Example 1 is shown in FIG. In this production example, a crucible in which neither the heat insulating portion nor the baffle plate was installed was used.

  In Production Example 1, the direction of the liquid flow on the surface of the raw material melt was unstable, but as the main liquid flow direction, the liquid flow S2a from the short side where the temperature of the raw material melt was high collided at the crucible center. And a liquid flow S2b in which the colliding liquid flow flows in any direction on the long side were observed.

(Production Example 2)
The structure of the crucible used in Production Example 2 will be described with reference to FIGS. 9 (A) and 9 (B). 9A is a top view of the crucible, and FIG. 9B is a cross-sectional view of the crucible taken along a cutting line IXB-IXB in FIG. 9A. In the present manufacturing example, the heat insulating portion 905 is installed on one side of the short side of the opening of the crucible main body 901 on the entry side of the base plate. The heat insulating portion 905 was installed so as to have an overhang length of about 270 mm from the short side of the crucible body toward the inside of the crucible body.

  In Production Example 2, the direction of the liquid flow on the surface of the raw material melt was unstable, but the opposite liquid flows S2a from both short sides installed the heat insulating portion 905 as the main liquid flow direction. A liquid flow that collides at a position near the short side that is not present and a liquid flow S2b in which the collided liquid flow flows in any direction on the long side were observed. The reason why the collision position of the opposing liquid flows S2a is close to the short side where the heat insulating portion 905 is not installed is that the temperature of the raw material melt on the short side where the heat insulating portion 905 is installed has increased, It is conceivable that the flow of the liquid flow having directionality from the short side where the portion 905 is installed to the other short side becomes stronger.

  A schematic cross-sectional view of the thin plate produced in Production Example 2 is shown in FIG. The average plate thickness of the thin plate was about 350 μm. The average thickness difference between the left and right thin plates was 22 μm. The thin plate produced when the liquid flow S2b did not exist had a small difference in the plate thickness. The standard deviation of the thin plate was about 23 μm, and the variation in the plate thickness difference was large. A possible reason for the large variation in the plate thickness difference is that the liquid flow was not stable.

(Production Example 3)
The structure of the crucible used in Production Example 3 will be described with reference to FIGS. 10 (A) and 10 (B). 10A is a top view of the crucible, and FIG. 10B is a cross-sectional view of the crucible taken along a cutting line XB-XB in FIG. 10A. In this production example, the heat insulating portion 1005 was installed on the two long sides of the opening of the crucible body 1001 and the one short side serving as the entry side of the base plate. The heat insulating portion 1005 is installed so as to have an overhang length of about 270 mm from the short side of the crucible body 1001 to the inside of the crucible body 1001 and an overhang length of about 50 mm from the long side to the inside of the crucible body 1001. did. Further, three baffle plates 1006 were installed inside the crucible body. Of the three baffle plates 1006, two are installed in parallel with each of the long sides at a position approximately 50 mm away from each of the two long sides of the crucible body 1001, and the remaining one is the installation of the heat insulating portion 1005. It was installed in parallel with the short side at a position about 150 mm away from the short side. In addition, it adjusted so that the upper end part of all the baffle plates might become a position below about 20 mm from the liquid level of a raw material melt. The thickness of all baffle plates was 2 mm. The length of the two baffle plates parallel to the long side of the crucible body in the direction parallel to the long side was 800 mm. The length of one baffle plate parallel to the short side of the crucible body in the direction parallel to the short side was 500 mm.

  In Production Example 3, the direction of the liquid flow S2 on the surface of the raw material melt was stable with directionality from the short side where the heat insulating portion 1005 was installed to the other short side. It is considered that this is because the flow of the liquid flow S2 having directionality from the short side where the heat insulating unit 1005 is installed to the other short side is strengthened by the effects of both the heat insulating unit 1005 and the baffle plate 1006. .

  A schematic cross-sectional view of the thin plate manufactured in Manufacturing Example 3 is shown in FIG. The average plate thickness of the thin plate was about 350 μm. The average thickness difference between the left and right thin plates was as small as 8 μm. The standard deviation of the thin plate was about 8 μm, and the variation in the plate thickness difference was small. This is presumably because the liquid flow S2 was stable with directivity from the short side where the heat insulating portion 1005 was installed to the other short side.

(Production Example 4)
The structure of the crucible used in Production Example 4 will be described with reference to FIGS. 11 (A) and 11 (B). FIG. 11A shows a top view of the crucible, and FIG. 11B shows a cross-sectional view of the crucible along the cutting line XIB-XIB in FIG. 11A. In this production example, the heat insulating portion 1105 was installed on the two long sides of the opening of the crucible main body 1101 and the one short side serving as the entry side of the base plate. The heat insulating portion 1105 is installed so as to have an overhang length of about 270 mm from the short side of the crucible body 1101 to the inside of the crucible body 1101 and an overhang length of about 50 mm from the long side to the inside of the crucible body 1101. did. Further, three baffle plates 1106 were installed inside the crucible body. Of the three baffle plates 1106, two are installed approximately 50 mm away from each of the two long sides of the crucible main body 1101 in parallel with each of the long sides, and the remaining one is provided with a heat insulating portion 1105. It was installed in parallel with the short side at a position about 150 mm away from the short side on the non-finished side. In addition, it adjusted so that the upper end part of all the baffle plates might become a position below about 20 mm from the liquid level of a raw material melt. The thickness of all baffle plates was 2 mm. The length of the two baffle plates parallel to the long side of the crucible body in the direction parallel to the long side was 800 mm. The length of one baffle plate parallel to the short side of the crucible body in the direction parallel to the short side was 500 mm.

  In Production Example 4, the main liquid flow on the surface of the raw material melt was a liquid flow S2a having a direction from the short side where the heat insulating portion 1105 was not installed to the other short side. This is considered because the liquid flow formation effect by the baffle plate 1106 is larger than the liquid flow formation effect by the heat insulating portion 1105. On the other hand, a liquid flow S2b having a direction perpendicular to the dipping direction of the base plate was also observed on the surface of the raw material melt immediately below the heat insulating portion installed on the short side of the crucible body. The liquid flow S2b includes a liquid flow S2a having a directivity from the short side to the other short side where the heat insulating portion 1105 is not provided, which is generated by the baffle plate, and a liquid flow facing the liquid flow S2a generated by the heat insulating portion. (Not shown) is considered to be a liquid flow generated by collision.

  A schematic cross-sectional view of the thin plate manufactured in Manufacturing Example 4 is shown in FIG. The average plate thickness of the thin plate was about 350 μm. The average thickness difference between the left and right thin plates was as large as 38 μm. This is considered because the liquid flow S2b perpendicular to the immersion direction S1 of the base plate was present. The standard deviation of the thin plate was about 14 μm, and the variation in the plate thickness difference was slightly large. This is considered to be caused by the disturbance of the liquid flow during the immersion of the base plate because the main liquid flow S2a and the base plate immersion direction S1 face each other.

(Discussion)
It is considered that the plate thickness difference of the thin plate can be reduced by reducing the liquid flow on the surface of the raw material melt having the direction perpendicular to the dipping direction of the base plate. Moreover, it is thought that the dispersion | variation in the plate | board thickness of a thin plate can be made small by making the immersion direction of a base plate and the direction of the liquid flow of the surface of a raw material melt into the same direction.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  100 thin plate manufacturing apparatus, 101, 201, 501, 601, 701, 801, 901, 1001, 1101 crucible body, 102, 202, 502, 602, 702, 802, 902, 1002, 1102 raw material melt, 103 heating section, 104, 304, 404, 904, 1004, 1104 Base plate, 105, 505, 705, 905, 1005, 1105 Thermal insulation part, 106, 606, 706 Baffle plate, 110 Horizontal motion rail, 111 Slide body, 112 Lifting mechanism, 113 Suspension strut, 114 rotating mechanism, 115 rotating strut, 116 pedestal support section, 117 pedestal, 120 immersion section, 320, 920, 1020, 1120 thin plate.

Claims (14)

A thin plate manufacturing apparatus for manufacturing a thin plate on the surface of the base plate by immersing the base plate in the raw material melt,
A crucible capable of filling the raw material melt therein;
An immersion part for immersing the base plate in the raw material melt in the crucible,
The said crucible is a thin plate manufacturing apparatus containing the crucible main body and the control part which controls the direction of the liquid flow on the surface of the said raw material melt according to the immersion direction of the said base plate.   The said control part is controlled so that the direction of the liquid flow on the surface of the said raw material melt becomes perpendicular | vertical with respect to the immersion direction of the said baseplate projected in parallel on the surface of the said raw material melt. Sheet metal manufacturing equipment.   The said control part controls so that the direction of the liquid flow on the surface of the said raw material melt may become parallel with the immersion direction of the said base plate projected in parallel on the surface of the said raw material melt. Sheet metal manufacturing equipment.   The said control part controls so that the direction of the liquid flow on the surface of the said raw material melt may become the same direction with respect to the immersion direction of the said base plate projected in parallel on the surface of the said raw material melt. The thin plate manufacturing apparatus described.   The said control part is a thin plate manufacturing apparatus in any one of Claims 1-4 which controls the direction of the liquid flow on the surface of the said raw material melt by controlling the temperature distribution of the surface of the said raw material melt.   The controller is configured such that the temperature of the surface of the raw material melt at a position where the base plate enters the raw material melt is higher than the temperature of the surface of the raw material melt at a position where the base plate escapes from the raw material melt. The thin plate manufacturing apparatus of Claim 5 which controls the temperature distribution of the surface of the said raw material melt so that it may become high.   The control part includes a heat insulating part, and the heat insulating part exposes the raw material melt to the outside of the crucible, and is provided in any one of an opening provided at an upper part of the crucible main body and an outer wall of the crucible main body. The thin plate manufacturing apparatus according to claim 5 or 6, wherein the thin plate manufacturing apparatus is installed in contact with each other and controls a liquid flow direction on the surface of the raw material melt by the heat insulating portion. The shape of the opening is line symmetric,
The said heat insulation part is a thin plate manufacturing apparatus of Claim 7 installed asymmetrically with respect to the any axis of symmetry of the said opening part projected in parallel on the surface of the said raw material melt.   The thin plate according to any one of claims 5 to 8, wherein the control unit includes a baffle plate installed inside the crucible body, and controls a direction of a liquid flow on a surface of the raw material melt by the baffle plate. Manufacturing equipment.   The baffle plate exposes the raw material melt to the outside of the crucible, and is an opening provided at the upper part of the crucible body, on the surface of the raw material melt of the opening having an axisymmetric shape. The thin plate manufacturing apparatus according to claim 9, wherein the thin plate manufacturing apparatus is installed asymmetrically with respect to any of the symmetry axes projected in parallel. The control unit includes a heat insulating unit and a baffle plate that control a liquid flow direction on the surface of the raw material melt, the heat insulating unit exposes the raw material melt to the outside of the crucible, and the crucible body Installed in contact with either the opening provided in the upper part and the outer wall of the crucible body, and the baffle plate is installed in the crucible body,
The heat insulating portion and the baffle plate are arranged such that the direction of the liquid flow on the surface of the raw material melt generated by the heat insulating portion is parallel to the direction of the liquid flow on the surface of the raw material melt generated by the baffle plate. The thin plate manufacturing apparatus of Claim 5 or 6 installed. The crucible body includes a substantially rectangular opening at the top for exposing the raw material melt to the outside of the crucible,
The control unit is installed substantially perpendicularly to the bottom surface of the crucible inside the crucible, and a heat insulating unit installed so as to cover at least three sides of the substantially rectangular opening and cover the upper part of the raw material melt. A first baffle plate, a second baffle plate and a third baffle plate,
When parallel projected onto the surface of the raw material melt, the first baffle plate and the second baffle plate face each other and are parallel to each other, and the third baffle plate is the first baffle plate. The thin plate manufacturing apparatus according to claim 11, wherein one end portion of the plate and one end portion of the second baffle plate are connected and are perpendicular to the first and second baffle plates. It is a thin plate manufacturing method using the thin plate manufacturing apparatus in any one of Claims 1-12,
Heating a raw material in a crucible to obtain a raw material melt;
Dipping a base plate in the raw material melt,
A method for producing a thin plate, wherein the direction of the liquid flow on the surface of the raw material melt is controlled according to the immersion direction of the base plate in the step of immersing the base plate. A crucible that can be filled with a raw material melt,
The crucible includes a crucible body and a control unit,
The crucible body includes a line-symmetric opening at the top for exposing the raw material melt to the outside of the crucible,
The said control part is a crucible in contact with the said crucible main body, and is installed asymmetrically with respect to any axis of symmetry of the said opening part projected in parallel on the surface of the said raw material melt.

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