JP2010235367A - Method for pulling down single crystal, crucible used in the method, and device for pulling down - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for pulling down single crystals having complicated cross-sectional shapes. <P>SOLUTION: A surface, in which an oozing-out hole opening for a raw material melt 9 is formed, under a crucible 11 is made an inclined surface, and the opening is arranged above the inclined surface. Patterns corresponding to cross-sectional shapes of single crystals are formed on the inclined surface. A seed 7 has a surface contacting with the melt 9 having one pattern formed corresponding to the cross-sectional shape of one single crystal, and the contact surface having the same inclination as the crucible 11 side. In seed touch, after the uppermost one of the seeds 7 is brought into contact with the lowermost one of the patterns of the crucible 11, the seeds 7 are moved parallelly along the inclined surface, and the seeds are finally disposed so as to face the respective patterns to complete the seed touch over the pattern entire region. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an apparatus for producing single crystals such as oxides, fluorides, and metal alloys used for so-called laser optical elements, nonlinear optical elements, medical scintillators, piezoelectric elements, giant magnetostrictive elements, and the like. More specifically, a pulling method for obtaining a desired crystal material while drawing a raw material melt from a hole provided at the lower end of the crucible, particularly a so-called micro pulling (μ-pD) method for obtaining a fiber-like single crystal. The present invention relates to a crystal manufacturing method, a crucible used in the manufacturing method, and a single crystal pulling apparatus.

  A pull-out hole is formed in the lower end of the crucible holding the heated and melted raw material, crystal nuclei (hereinafter referred to as seeds) are brought into contact with the raw material melt leaked from the hole, and leakage of the raw material from the hole is caused. A so-called pulling-down method (see Patent Documents 1 to 3) is known in which a single crystal that grows using the seed as a nucleus is obtained by pulling down the seed. A single crystal obtained by this method has a smaller crystal diameter than a single crystal obtained by a so-called pulling method represented by a conventionally known CZ method. However, as a method for obtaining a single crystal having a short time required for crystal growth and excellent in crystallinity at a low cost as compared with the CZ method, it is necessary to modify the actual manufacturing equipment in terms of hardware and various single units. Application to crystals has been studied.

  In the pulling-down method, there is a so-called micro-pulling-down method as a method for obtaining a fiber crystal having higher crystallinity and maintaining a high crystal growth rate. Using this method, a fluoride single crystal such as calcium fluoride used for an optical material for excimer laser, or an oxide single crystal such as alumina or calcia, and also a giant magnetostrictive material exemplified by so-called terphenol D Manufacturing conditions for single crystals are being studied.

JP 2003-095783 A JP 11-278994 A JP 04-280891 A

  In the above-described micro-pulling-down method, a rod-shaped single crystal is generally manufactured using various materials. However, when the single crystal actually obtained is limited to a rod shape, when a product is obtained using the single crystal, the single crystal is post-processed so as to have a shape corresponding to the product. Is required. For example, when it is desired to use this single crystal for a covering material such as a scintillator element or a collection of covering materials, it is difficult to actually obtain such a shape by post-processing. For this reason, attempts have been made to obtain a single crystal having a hollow cylindrical or rectangular tube shape at the stage of the pulling-down operation at the time of producing the single crystal. As a specific example, Patent Document 3 discloses a configuration for producing a cylindrical single crystal. That is, a so-called hollow pipe-shaped member is used to form a circular gap, and a raw material melt is drawn from the gap to obtain a cylindrical single crystal. Further, a flat crystal seed is preferably brought into contact with the raw material melt leaked from the gap uniformly over the entire gap, and in this state, the seed is pulled down to suitably obtain a single crystal growth state. I am trying to do. The seed described here refers to a member collectively called a so-called seed crystal that determines the crystal orientation when the raw material melt is crystallized in contact with the raw material melt.

  It is easy to simply contact the seed against the raw material melt. However, the contacted seed forms a so-called meniscus that is a solid-liquid boundary region with respect to the raw material melt, and it is actually necessary to obtain and maintain a state where the meniscus is uniformly generated in a predetermined range. Have difficulty. In particular, when the region to be contacted has a shape that spreads in a plane, it is difficult to obtain a state of suitable contact over the entire region. Specifically, by visually observing the contact point between the seed and the raw material melt and the vicinity thereof, contact between the seed and the raw material melt and further reducing the amount of the seed many times until an appropriate contact state is obtained. It is known to depend on the skill of the operator, such as repetition. Therefore, in the case of the configuration disclosed in the cited document 3, it is practically difficult to appropriately pull down and grow the single crystal from the beginning while maintaining the annular shape of the raw material melt leaking from the annular opening of the crucible. there were. In addition, due to the effect of the meniscus being generated near the annular opening, it is actually difficult to obtain a state in which the raw material melt leaks evenly from the entire area with good reproducibility.

  The present invention has been made in view of the above situation, and for a single crystal having a so-called hollow shape, a method for pulling down a single crystal that can be suitably and stably manufactured regardless of an operator of the manufacturing apparatus, Another object of the present invention is to provide a crucible or a pulling device suitable for the method.

  In order to solve the above-described problems, the method for pulling down a single crystal according to the present invention includes a main body capable of holding a raw material and a melt of the raw material inside, and a raw material melt leaking in communication with the inside of the main body. A single crystal pulling method for obtaining a single crystal by bringing a seed into contact with a raw material melt leaked from a leak hole of a crucible having a leak hole and pulling the seed along a predetermined pulling axis extending in a vertical direction. The opening end face where the leakage hole opens has a planar spreading part made of a raw material melt and a material with good wettability and constituting a pattern corresponding to the cross-sectional shape of the single crystal. The extending portion extends in an inclined surface arranged so as to be inclined at a predetermined angle with respect to the lowering axis, and the pattern has the highest region and the lowest region in the inclined surface. Each surface included in the pattern is along the inclined surface Arranged and the opening of the leak hole is provided in the highest region, has a pattern corresponding to the crucible and the spreading portion, and becomes the highest and the lowest in the vertical direction by tilting by a predetermined angle And a seed that defines a crystal orientation when the raw material melt is crystallized, and the raw material melt is leaked from the opening of the leakage hole of the crucible and leaked raw material Wet and spread the melt to the lowest area of the spreading part, and bring the highest area on the seed touch surface close to the lowest area of the spreading part to a position that is a predetermined distance away. The rising area is brought into contact with the raw material melt present in the lowest area of the spreading section, and the seed touch surface is maintained at a predetermined distance from the spreading section. Move in parallel with the existing surface to make the highest area on the seed touch surface and the highest area on the spreading part face each other, generate a meniscus in the whole area between the seed touch surface and the spreading part, and in the pull-down direction It is characterized by growing the single crystal by lowering the seed.

  Regarding the method for pulling down the single crystal described above, the temperature T1 of the raw material melt when generating the meniscus is preferably set lower than the temperature T2 of the raw material melt when translating the seed touch surface. . Further, when the seed touch surface is translated, it is preferable that the seed touch surface is translated along the pattern shape.

  In order to solve the above problems, the crucible used in the single crystal pulling method according to the present invention holds the raw material melt in the internal space in the cylindrical main body with the bottom closed, and leaks from the internal space. A crucible used in a pulling device for obtaining a single crystal by bringing a seed into contact with a raw material melt to be pulled and pulling the seed along a predetermined pulling axis, and a cylindrical inner space with a closed bottom, A leakage hole extending from the inner space to the outer space through the bottom, and a planar spreading portion made of a raw material melt and a material with good wettability and forming a pattern corresponding to the cross-sectional shape of the single crystal. The spreading portion extends in an inclined surface arranged so that the normal line of the extending portion is inclined at a predetermined angle with respect to the central axis of the main body portion, and the pattern is the highest region in the inclined surface. With the lowest area and included in the pattern. Surfaces which are disposed along the inclined surface, the opening of the leak hole is characterized in that it is provided in the highest becomes region.

  In order to solve the above problems, a single crystal pulling apparatus according to the present invention includes the above-described crucible, and is further arranged by winding the crucible so that a high-frequency current can be conducted. A heating coil capable of generating a magnetic field, and a seed holder that holds a seed that defines a crystal orientation when the raw material melt is crystallized, and lowers the seed along a predetermined pulling axis extending in a vertical direction. The heating coil is characterized in that it has a region that becomes a central axis that coincides with the normal line of the extending portion in part, or can be tilted so that the normal line and the central axis coincide with each other. Note that the single crystal pulling device preferably further includes a seed touch surface driving unit capable of moving the seed holder in parallel with the extending portion of the crucible.

  According to the present invention, in the method of pulling down a single crystal having a hollow shape, so-called seed touch in which a seed crystal seed is brought into contact with a raw material melt can be reliably, stably and reproducibly performed. It becomes. More specifically, according to the present invention, the front end portions of the opening forming surface (the surface of the expanding portion described later) and the seed in the crucible, and a slight region in which the projected regions in the pull-down axis direction overlap each other. Therefore, seed touch at the initial stage can be easily and reliably performed. In addition, the opening formation surface and the seed touch surface are formed in parallel to each other, and after this initial stage seed touch, the seed touch surface is moved in parallel while maintaining a certain distance from the opening formation surface, so that the opening formation surface is wet spread. The contact state between the raw material melt and the entire seed touch surface is obtained using the surface tension of the raw material melt. Accordingly, this contact state can be obtained easily and reliably, and the seed touch surface is complicated and has a void in the inside thereof, and the seed touch with respect to the raw material melt can be reliably performed over the entire area.

  Further, according to the present invention, after the raw material melt is spread over the entire area where the opening is formed, the seed is contacted so as to prevent the raw material melt from dripping from the lowest axial end of the opening forming surface. This creates a meniscus (solid-liquid boundary). Accordingly, there is no adverse effect on the meniscus formation due to the excess raw material melt, and a preferable meniscus formation state can be obtained. Further, according to the present invention, the pattern of the spreading portion is formed so that the spreading portion where the raw material melt formed on the opening forming surface spreads out is inclined from a high region to a low region with respect to the vertical direction. The raw material melt wets and spreads on the forming surface in accordance with the direction of gravity action. Therefore, the raw material melt easily and reliably spreads over the entire area where the opening is formed.

  Further, according to the present invention, when the central axis of the heating coil is inclined, the in-plane temperature at the opening forming surface formed to be inclined with respect to the pulling axis when the single crystal pulling method according to the present invention is performed. It becomes possible to improve uniformity. Accordingly, it is possible to stably generate a meniscus parallel to the opening forming surface. Further, according to the present invention, as described above, the seed touch surface is translated so that the opening forming surface and the seed touch surface maintain a predetermined distance, and the meniscus is utilized by utilizing the surface tension of the raw material melt. The generation area is expanded. Here, it is impossible to arrange the crucible opening on the opening forming surface at the uppermost part of the opening end face which is an inclined surface by design, and a region existing at a higher position in the axial direction than the crucible opening on the inclined surface. Depending on the material, it may be difficult to spread the raw material melt. However, as in the present invention, the seed touch surface to which the raw material melt has previously adhered is translated so that it overlaps the opening forming surface of the crucible, and the wetness of the raw material melt is utilized to make the seed touch surface parallel. After the movement, the raw material melt can be wetted and spread also in the region. Therefore, it is possible to easily obtain an end crystal having, for example, a hollow region according to the shape of the seed touch surface.

It is the figure which extracted the characteristic part of the crucible which concerns on one Embodiment of this invention, and showed this typically. It is the figure which looked at the advancing part in the crucible concerning other embodiments of the present invention from the front, and is a figure showing typically the specific stage at the time of wet spread of raw material melt. It is the figure which looked at the advancing part in the crucible shown in FIG. 2A from the front, Comprising: It is a figure which shows typically the specific stage at the time of the wetting spread of a raw material melt. It is the figure which looked at the advancing part in the crucible shown in FIG. 2A from the front, Comprising: It is a figure which shows typically the specific stage at the time of the wetting spread of a raw material melt. It is the figure which looked at the advancing part in the crucible shown in FIG. 2A from the front, Comprising: It is a figure which shows typically the specific stage at the time of the wetting spread of a raw material melt. It is the figure which looked at the spread part in the crucible concerning the further embodiment of the present invention from the front, and is a figure showing typically the specific stage at the time of the wetting spread of the raw material melt. It is the figure which looked at the advancing part in the crucible shown in FIG. 3A from the front, Comprising: It is a figure which shows typically the specific stage at the time of wet spreading of a raw material melt. It is the figure which looked at the advancing part in the crucible shown in FIG. 3A from the front, Comprising: It is a figure which shows typically the specific stage at the time of wet spreading of a raw material melt. It is the figure which looked at the advancing part in the crucible shown in FIG. 3A from the front, Comprising: It is a figure which shows typically the specific stage at the time of wet spreading of a raw material melt. It is a flowchart which shows the manufacturing process of a single crystal. It is a figure which shows typically the state of the actual apparatus corresponding to step S1 shown in FIG. It is a figure which shows typically the state of the actual apparatus corresponding to step S2 shown in FIG. It is a figure which shows typically the state of the actual apparatus corresponding to step S3 shown in FIG. It is a figure which shows typically the state of the actual apparatus corresponding to step S4 and step S5 shown in FIG. It is a figure which shows typically the state of the actual apparatus corresponding to step SS6 and step S7 shown in FIG. It is a figure which shows typically the state of the actual apparatus corresponding to step S8 shown in FIG. FIG. 6 is a schematic side view schematically showing a configuration for performing parallel translation of a seed. It is a figure which shows schematic structure of the pulling apparatus suitable for implementation of the pulling-down method of the single crystal which concerns on this invention. FIG. 8 is a diagram showing an extracted characteristic portion of the device in the configuration shown in FIG. 7. FIG. 9 is a diagram showing a state where the coil is actually tilted in the configuration shown in FIG. 8. FIG. 9 is a diagram showing a state where the coil is actually tilted in the configuration shown in FIG. 8.

  An embodiment of the present invention will be described below with reference to the drawings. First, about a crucible used in a method for pulling down a single crystal according to an embodiment of the present invention, a schematic view of an opening for leaking a raw material melt in the crucible and the vicinity of an opening forming surface where the opening is formed. It is shown in 1. FIG. 1 shows a cut surface when a bottom region of a crucible is cut along a leakage hole (a pulling-down direction of a single crystal) of a raw material melt, and an opening end surface where the leakage hole opens is opposed to a normal line of the end surface. The state seen from the direction is shown. In the present embodiment, the case where the purpose is to grow a single crystal having a square tube shape with a cross-sectional shape is illustrated. In one embodiment of the present invention, the crucible 11 includes a tubular main body (not shown) whose lower end is closed, and an internal space of the main body that extends in parallel to the central axis C of the main body. A leakage hole 11a that communicates with the outside of the bottom of the crucible 11, and a conical shape having the leakage hole as a top, connecting the main body part and the leakage hole, and an axial connection part 11b. A raw material or a raw material melt 9 obtained by dissolving the raw material is held in an internal space formed by the main body portion and the axial direction connecting portion 11b. That is, in other words, the crucible 11 has a cylindrical internal space with a closed bottom, a leakage hole 11a from the internal space to the external space through the bottom, and a raw material formed on the external space side of the bottom. It is comprised from the planar extending part 11d which consists of a material with good melt and wettability, and comprises a desired pattern. Further, the opening end surface 11c (that is, the spreading portion 11d) where the leakage hole 11a opens is configured such that the normal line H is inclined at a predetermined angle α with respect to the center axis C of the crucible 11 described above. In addition, it is preferable that the said center axis | shaft C is arrange | positioned in agreement with the perpendicular direction which is also a pulling-down direction. In addition, it is preferable that the predetermined pull-down axis coincides with the vertical direction in order to leak the raw material melt using gravity, but the pull-down axis is set with respect to the vertical direction according to the purpose, for example, by tilting the crystal orientation. It is also possible to tilt.

  In this example, an attempt is made to obtain a square tube-shaped single crystal having a cross-sectional frame shape. For this reason, the opening end surface 11c is formed with a frame-shaped raw material melt spreading portion 11d having a pattern corresponding to the cross-sectional shape. The spreading portion 11d matches the frame shape of the single crystal that the projection shape along the central axis C is to be obtained. In the present embodiment, the spreading portion 11d is obtained by exposing the surface of the opening end surface 11d to a desired planar shape that is formed using a material that has a good wettability with respect to the raw material melt 9. However, for example, the extended portion 11d may be formed so as to protrude in the normal H direction, and the protruding surface may be configured so that the raw material melt spreads. That is, it is only necessary to obtain a state in which the raw material melt 9 is quickly spread out in a state where the raw material melt 9 is limited on the surface of the spreading portion 11d. Moreover, the opening part in the opening end surface 11c of the leak hole 11a is formed in the highest area | region in the extending part 11c in the state which has arrange | positioned the center axis | shaft vertically. By having the above configuration, the raw material melt 9 leaked from the open end surface 11d of the crucible 11 is caused by the action of gravity to be from the top (highest region) to the bottom (lowest region) of the surface of the extended portion 11d. ) And quickly spread out and develop into a predetermined pattern (in this case, a frame shape).

  In the present invention, the quality of the wettability between the raw material melt 9 and the spreading part 11d is defined as one of the characteristics of the spreading part 11d. Here, with respect to the so-called contact angle when the raw material melt is present on a flat plate material having the same material and surface state as the hole opening of the crucible, the case where the contact angle is 90 ° or more is wetted. A material having low wettability is defined, and a case where it is less than 90 ° is described as a material having high wettability.

  FIGS. 2A to 2D are schematic and steps showing a state in which the raw material melt 9 spreads out in the case of the crucible having the form shown in FIG. 1 and the inclined portion 11d extending along the one-dot chain line T in the drawing. Is shown. In this example, the inclination direction is arranged so as to go from one corner of the frame shape to the opposite corner. The stage before the raw material melt 9 leaks from the leak hole 11a is shown in FIG. 2A. In this state, the leakage of the raw material melt 9 starts from the leakage hole 11a. The leaked raw material melt 9 starts to spread preferentially on the spreading portion 11d having good wettability, and reaches the state shown in FIG. 2B and further in FIG. 2C. Note that it is practically impossible to arrange the opening position of the leakage hole 11a at the end of the opening end face 11c that is highest in the vertical direction in the opening end face 11c. However, in the present invention, for convenience, the opening is described as being formed at the highest position (formable) in the extended portion 11d. After passing through the state shown in FIG. 2C, the raw material melt 9 reaches the lowermost end in the spreading portion 11d. Here, when the wettability between the raw material melt 9 and the material constituting the spreader 11 is sufficiently large, due to the effect of this wettability, the region of the spreader 11d existing at a position higher than the opening is used. Until the raw material melt spreads. However, depending on the wettability, it may be difficult to spread more than a certain amount due to the influence of gravity. In this embodiment, by moving the seed touch surface to a position where an upper end portion of the seed touch surface, which will be described later, and the region oppose each other, the surface tension of the raw material melt 9 is used to expand the raw material melt 9 to the region. Is going to do.

  3A to 3D schematically and stepwise show a state in which the raw material melt 9 spreads out in the same manner as in FIGS. 2A to 2D in the case of obtaining a tube-shaped single crystal having a circular cross-sectional shape. Show. In this example, the spreading part 11d has an annular pattern. 3A to 3D also show a case where the extending portion 11d is arranged so that the inclination direction of the opening end surface 11c is along the alternate long and short dash line T in the drawing. Further, the same components as those in FIG. 2A and the like will be described using the same reference numerals. The stage before the raw material melt 9 leaks from the leak hole 11a is shown in FIG. 3A. In this state, the leakage of the raw material melt 9 starts from the leakage hole 11a. The leaked raw material melt 9 starts to spread preferentially on the spreading portion 11d with good wettability, and reaches the state shown in FIG. 3B and further in FIG. 3C. Thereafter, by moving a seed touch surface, which will be described later, to a position facing the spreading portion 11d, a state in which the raw material melt 9 is wet and spread with respect to the front surface of the spreading portion 11d as shown in FIG. 3D is obtained. After this state is obtained, the seed touch surface is actually pulled down in the vertical direction, and the growth of the tubular single crystal is executed.

  Next, an embodiment of a specific single crystal growth method will be described below. FIG. 4 is a flowchart showing a single crystal growth procedure, and FIGS. 5A to 5F schematically show the states in the respective steps shown in the flowchart shown in FIG. 4 in the same manner as FIG. Yes. First, in step S1, raw materials are put into the crucible 11, and the so-called high frequency is applied to the heating coil 17 disposed so as to surround the crucible 11 as shown in FIG. The raw material melted by the heating of the crucible 11 reaches the expanding portion 11d as the raw material melt 9 through the leak hole 11a, and spreads over the expanding portion 11d as described in step S2. As shown in FIG. 5B, this state is maintained until the raw material melt 9 that has spread out reaches the lower end of the spreading portion 11d. Thereafter, the seed touch surface 7a formed in parallel with the surface of the spreading portion 11d and movable in parallel with respect to the spreading portion 11d is set to the lowest position in the spreading portion 11d. A so-called point touch is performed facing the existing area (step S3 and FIG. 5C). That is, in the point touch, a state is obtained in which the raw material melt 9 that has reached the lowest position of the spreading portion 11d is in contact with the seed touch surface 7a that is disposed at a predetermined distance from the spreading portion 11d. As described above, the seed touch surface 7 has a normal line that is opposite to the above-described normal line H of the extended part so as to be parallel to the extended part 11d, and has the same shape as the extended part 11d. . Further, by translating the seed touch surface 7a, for example, in the case of the extending portion 11d having a frame shape, the frame shape of the seed touch surface 7a faces the frame shape. That is, the seed touch surface 7a forms an inclined surface that is inclined at a predetermined angle with respect to the pull-down axis similarly to the extending portion 11d, and has a shape in which the patterns are completely opposed to each other in a state facing the extending portion 11d. .

  After the point touch shown in FIG. 5C is established, as shown in FIG. 5D, the seed touch surface 7a is translated along the inclination of the expanding portion 11d (step S4). In the actual parallel movement, the configuration shown in a simplified manner in FIG. 6 is used. The seed 7 having the seed touch surface 7a is supported by a seed holder 8 extending in the vertical direction. The seed holder 8 is supported by the inclination correction unit 5. The inclination correction unit 5 has an inclined surface 5a having the same normal line as the seed touch surface 7a with respect to the vertical direction, and the seed holder 8 is moved along the inclined surface 5a by the seed holder moving motor 4. These configurations are collectively referred to as a seed touch surface drive unit. The seed touch surface 7a performs the above-described parallel movement by the function of the configuration described here. The parallel movement is stopped when the region existing at the highest position on the seed touch surface 7a faces the region existing at the highest position on the spreading portion 11d. During this parallel movement, the spreading portion 11d and the seed touch surface 7a always maintain a predetermined distance. However, it is possible to keep the state that the raw material melt 9 is in contact with the seed touch surface 7a and that the predetermined distance is in contact with both the spreading portion 11d and the seed touch surface 7a due to the influence of surface tension. By setting the interval, the area in contact with the seed touch surface 7a is sequentially expanded as the seed touch surface 7a moves in parallel. That is, the seed touch surface 7a performs the above-described parallel movement while maintaining the state in contact with the raw material melt 9, in other words, expanding the contact area. Therefore, by the above operation, in the state where the seed touch surface 7a and the spreading portion 7 are completely opposed to each other, the raw material melt 9 is sandwiched across the entire area, and the entire seed shown in step S5 is obtained. Touch is complete.

  As shown in step S6, this state is maintained for a predetermined time in order to stabilize the contact state between the raw material melt 9 and the seed touch surface 7a. Thereby, the meniscus 9a is produced | generated between the seed touch surface 7a and the expansion part 11d (refer FIG. 5E). After the meniscus 9a is generated, the seed 7 starts to be pulled down as described in step S7, and the single crystal 9b is grown as described in step S8 (FIGS. 5E and 5F). At the time of the pulling-down operation, the raw material melt 9 is appropriately supplied from the inside of the crucible 11, so that the position and shape of the meniscus 9b, which is the contact portion obtained by the seed touch on the entire surface, are maintained even at the time of pulling down. The After the predetermined amount of pulling-down operation is completed and the growth of a single crystal having a predetermined length is completed, the single crystal 9b described in step S9 is cooled and the single crystal 9b described in step S10 is taken out. By carrying out the above operation, for example, it becomes possible to grow a single crystal having a complicated cross-sectional shape having a square cross section and a void inside.

  That is, in the present invention, the opening end surface 11c having the extending portion 11d, which is a region that is inclined in a predetermined direction with respect to the crucible 11 and has a good wettability of the raw material melt 9 having a predetermined planar shape, is used as the lower end surface. It is arranged. Further, at the same time, in the extending portion 11d, it is configured not to form a surface extending in the horizontal direction, and an area existing at the highest position and an area existing at the lowest position in the vertical direction are arranged, Further, the height is linearly changed from the high position to the low position. Moreover, the opening part of the leak hole 11a which leaks the raw material melt 9 from the inside of the crucible 11 to this opening end surface 11c is arrange | positioned in the area | region which exists in the highest position. By satisfying the condition, the raw material melt 9 can be wetted and spread over the entire surface of the spreading portion 11d using gravity. Further, in the present invention, the seed touch surface 7a is inclined so as to be parallel to the inclined extended portion 11d, and the shape of the inclined surface matches the shape of the extended portion 11d, and the seed touch surface 7a. And the spreading portion 11d are set at a predetermined interval that can maintain the state in contact with both due to the surface tension of the raw material melt 9. First, the region that is the highest position of the seed touch surface 7 that satisfies the condition is first brought into contact with the raw material melt 9 that exists in the region that is the lowest position of the spreading portion 11d, and this contact state is maintained to maintain the sheet touch surface 7a. Is moved in parallel with the inclined surface, it is possible to obtain a state in which the raw material melt 9 is in contact with the entire seed touch surface 7a evenly and stably. By carrying out the pulling operation under predetermined pulling conditions while maintaining the state, even a single crystal having a complicated and hollow cross section can be easily grown.

  In the above-described embodiment, the temperature at which the raw material melt is held for the formation of the meniscus 9a is the first set temperature T1, and the set temperature of the raw material melt at the time of so-called point touch is set to When the second set temperature T2 is used, it is necessary to satisfy the condition of T1 <T2. In other words, when the raw material melt 9 is wetted and spread on the spreading portion 11d, it is preferable to maintain the melt temperature high in order to reduce the so-called viscosity of the raw material melt 9. On the other hand, the formation temperature of the meniscus 9a is almost the so-called eutectic temperature, and therefore, the above conditions need to be satisfied. Moreover, in embodiment mentioned above, only the case where the seed 7 moves linearly along a predetermined inclined surface is illustrated. However, for example, when the cross-section of the single crystal to be obtained has a relatively simple shape, if the seed touch surface is in a direction in which the moving direction of 7a is always moved from a low position to a high position, it will follow the shape. It is also possible to move the seed. This makes it possible to reliably perform seed touch throughout the entire area.

  Next, a pulling apparatus suitable for carrying out the single crystal pulling method according to the present invention will be described. In the pulling-down method described above for one embodiment, the open end surface 11c of the crucible 11 is arranged to be inclined with respect to the horizontal plane (vertical direction). For this reason, in the structure which maintained the temperature uniformity in the conventional horizontal surface, it is thought that a suitable soaking | uniform-heating area | region cannot be obtained in the surface of the opening end surface 11c. The pulling device described below has been devised in view of such a situation. FIG. 7 schematically shows a schematic configuration of a main part of the pulling-down device 1 according to the embodiment of the present invention. The pulling device 1 includes a crucible 11, an after heater 13, a heat retaining tube 15, a heating coil 17, a tube stage 19, a stage holder 16, a seed holder 8, and a holder chuck 18 around a pulling shaft. Moreover, these structures are arrange | positioned inside the vacuum chamber 43 which can supply pressure reduction and the specific gas with respect to interior space. As described above, the heating coil 17 emits a high frequency to the crucible 11 and heats the crucible 11 to a predetermined temperature. More specifically, a high-frequency current can be conducted, a high-frequency magnetic field is generated by flowing the high-frequency current, and a conductive object disposed therein is heated by induction heating with the high-frequency magnetic field. The heat retaining tube 15 has a role of suppressing the amount of heat radiated from the crucible 11 and returning the radiant heat to the crucible 11. Further, the after heater 13 is used in the vicinity of the crucible 11 during the pulling-down operation, and is used for heating and stabilizing the temperature in the space where the single crystal is actually grown. The tube stage 19 supports the crucible 11, the after heater 13, and the heat retaining tube 15 in the vacuum chamber 42. In addition, the stage holder 16 adjusts the height of the tube stage 19 and maintains various configurations supported by the tube stage 19 at predetermined positions (heights) with respect to the heating coil 17. The seed 7 described above is held on the lowering shaft by the seed holder 8 arranged on the lowering shaft. Further, the holder chuck 18 connects the seed holder 8 to a pull-down drive unit described later.

  A so-called bellows 43 a is disposed coaxially with the seed holder 8 on the bottom surface of the vacuum chamber 43. The lower end portion of the holder chuck 18 is fixed to the θ table 47 fixed to the lower end of the bellows 43a through the internal space of the bellows 43a. A Y table 49 and an X table 51 are attached to the lower portion of the θ table 47. The Y table 49 and the X table 51 are rotated around the lowering shaft with respect to the seed 7 via the holder chuck 18 and the seed holder 8, and are perpendicular to the lowering axis. The movement in the Y direction and the movement in the X direction perpendicular to the pull-down axis and the Y direction are given. In addition, these components are integrally supported by the Z-axis adjusting mechanism 53 and can be moved minutely in the pull-down axis direction that is the Z-axis. Further, the θ table 47, the Y table 49, and the X table 51 are fixed to be slidable with respect to a pull-down guide 55 that extends in the pull-down axis direction as a unit, and are fixed along the pull-down guide 55 by a pull-down motor 57. The seed 7 can be lowered at a speed. The vacuum chamber 43 is provided with a viewing window (not shown) so that the state of the meniscus 9a can be observed through the viewing window. In the illustrated apparatus, a CCD camera 59 is arranged outside the viewing window so that the central axis of the visual field coincides with the observation axis.

  Next, the heating coil turning mechanism which is a characteristic configuration of the present invention added to the above-described pulling device 1 will be described. FIG. 8 is a front view in which only the heating coil 17, the crucible 11, and the seed holder 8 are extracted from the configuration shown in FIG. 7, and the heating coil turning mechanism 60 provided along with these configurations and the heating coil 17. The included side view is depicted as the same drawing. The heating coil turning mechanism 60 includes a coaxial cable 61, a first connecting portion 63, a second connecting portion 65, a bearing flange 67, a bearing mechanism 69, a bearing clamper 71, and a rotation drive source 73. The coaxial cable 61 has a leading end inserted into the vacuum chamber 43 through a through hole provided in the wall of the vacuum chamber 43. The bearing mechanism 69 rotatably supports the coaxial cable 61 outside the vacuum chamber 43. The bearing mechanism 69 is fixed to the vacuum chamber 43 by a bearing flange 67 and a shaft clamper 71, and the airtightness of the vacuum chamber 43 is maintained by these configurations. A high-frequency transmission cable (not shown) brought into the vacuum chamber 43 by the coaxial cable 61 is connected to both ends of the heating coil 17 through the first connecting portion 63 and the second connecting portion 65. The coaxial cable 61 is connected to a rotation drive source 73 composed of a known gear, motor, etc. The rotation drive source 73 enables the coaxial cable 61 to rotate around the central axis.

  The central axis of the coaxial cable 61, that is, the turning center of the heating coil 17 in the heating coil turning mechanism 60 coincides with the opening of the leakage hole 11 a in the crucible 11. Actually, the state when the turning operation of the heating coil 17 is performed is shown in FIG. 9A in the case of the clockwise turning by extracting only the main components, and in the case of the left turning in FIG. 9B. By adding the heating coil turning mechanism 60 to the pulling device 1 in this manner, it is possible to incline a soaking area arranged on a plane perpendicular to the central axis of the conventional heating coil with respect to the central axis. Therefore, when carrying out the above-described lowering method, it is possible to arrange the soaking zone in parallel with the extending direction of the extending portion 11d. As a result, the meniscus 9a can be formed in parallel with the advancing portion 11d, and a suitable lowering operation can be performed.

  In the above-described embodiment, the heating coil turning mechanism 60 employs a mode in which the coaxial cable 61 is rotated. However, from the standpoint of maintaining the degree of vacuum in the vacuum loss 43 or the actual amount of swiveling, the swiveling mechanism may be constructed by various known configurations. In the present embodiment, the heating coil 17 is swung. However, in the actual growth of a single crystal, the shape of the crucible 11 is determined according to the shape of the single crystal to be grown. It is necessary to replace the crucible 11 according to the single crystal. Therefore, an auxiliary second heating coil that can form a soaking zone according to the crucible 11 may be provided separately from the heating coil 17. By arranging the second heating coil so as to be inclined with respect to the pulling shaft, the same effect as in the above embodiment can be expected. Alternatively, the shape of the heating coil 17 itself may be determined in advance in relation to the crucible 11, and the heating coil 17 may be replaced with a corresponding one when the crucible 11 is replaced. That is, if the heating coil 17 has a shape in which a part thereof is bent and the central axis is bent, and the central axis in the bent part coincides with the normal line of the extending portion 11d, the above condition can be satisfied. It is thought that. Therefore, the heating coil in this apparatus has a region that becomes a central axis that partially coincides with the normal line of the expanding portion 11d, or a heating coil turning mechanism so that the central axis can coincide with the normal line. 60 is preferably defined as being tiltable.

  As described above, according to the present invention, it is possible to perform a suitable and stable seed touch regardless of an operator of a manufacturing apparatus in a manufacturing process of a single crystal having a so-called hollow shape. Therefore, even a single crystal having a complicated cross-sectional shape and having voids can be manufactured with good reproducibility.

DESCRIPTION OF SYMBOLS 1: Pulling-down apparatus 4: Seed holder movement motor 5: Inclination correction unit 7: Seed 8: Seed holder 9: Raw material melt 11: Crucible 13: After heater 15: Insulating tube 16: stage holder, 18: holder chuck, 19: tube stage, 43: vacuum chamber, 47: θ table, 49: Y table, 51: X table, 53: Z-axis adjustment mechanism, 55: pull-down guide, 57: Pull-down motor, 59: CCD camera, 60: heating coil turning mechanism, 61: coaxial cable, 63: first connecting part, 65: second connecting part, 67: bearing flange, 69: bearing mechanism, 71: bearing clamper 73: Rotation drive source

Claims (6)

The raw material melt leaked from the leakage hole of the crucible having a main body capable of holding the raw material and the raw material melt therein, and a leak hole communicating with the inside of the main body portion and capable of leaking the raw material melt. A method of pulling down a single crystal to obtain a single crystal by bringing a seed into contact with a liquid and pulling down the seed along a predetermined pulling axis extending in a vertical direction,
The opening end face where the leakage hole opens is made of a material having good wettability with the raw material melt, and has a flat spreading portion constituting a pattern corresponding to the cross-sectional shape of the single crystal,
The spreading portion extends in an inclined surface arranged so that a normal line of the spreading portion is inclined at a predetermined angle with respect to the pull-down axis,
The pattern has a highest region and a lowest region in the inclined surface, each surface included in the pattern is disposed along the inclined surface, and the opening of the leakage hole is the highest. A seed touch surface having a pattern corresponding to the crucible and the extension portion, and a region that is highest and lowest in the vertical direction by tilting the predetermined angle. A pulling method using the seed that defines a crystal orientation when the raw material melt is crystallized,
Let the raw material melt leak through the opening of the leak hole of the crucible,
Spreading the leaked raw material melt to the lowest area of the spreader,
The highest region on the seed touch surface is brought close to the lowest region of the spreading portion to a position spaced by a predetermined distance, and the highest region on the seed touch surface is the highest in the spreading portion. Contacting the raw material melt present in the lowering region;
The seed touch surface is moved in parallel with the extending surface of the spreading part while maintaining the predetermined distance between the seed touch surface and the highest part of the seed touch surface and the spreading part. Facing the highest area,
Generating a meniscus in the entire area between the seed touch surface and the spreading portion;
A method for pulling down a single crystal, wherein the seed is pulled down in the pulling direction to grow a single crystal.   The temperature T1 of the raw material melt at the time of generating the meniscus is set lower than the temperature T2 of the raw material melt at the time of translating the seed touch surface. A method of pulling down a single crystal.   The pulling-down method according to claim 1, wherein when the seed touch surface is translated, the seed touch surface performs the parallel movement along the shape of the pattern. The raw material melt is held in the internal space of the cylindrical main body with the bottom closed, the seed is brought into contact with the raw material melt leaked from the internal space, and the seed is pulled down along a predetermined pull-down axis. A crucible used in a pulling device for obtaining a single crystal by:
The cylindrical internal space closed at the bottom, and
A leakage hole from the internal space to the external space through the bottom,
The material is composed of a material having good wettability with the raw material melt, and has a planar spreading portion that forms a pattern corresponding to the cross-sectional shape of the single crystal,
The spreading portion extends in an inclined plane arranged so that a normal line of the spreading portion is inclined at a predetermined angle with respect to a central axis of the main body portion,
The pattern has a highest region and a lowest region in the inclined plane,
A crucible for a single crystal pulling apparatus, wherein each surface included in the pattern is disposed along the inclined surface, and the opening of the leakage hole is provided in the highest region. A crucible according to claim 4,
A heating coil that is wound around the crucible so that a high-frequency current can be conducted and a high-frequency magnetic field can be generated in the high-frequency current;
A seed holder that holds a seed that defines a crystal orientation when the raw material melt crystallizes, and pulls down the seed along a predetermined pulling axis extending in a vertical direction,
The heating coil has a region that becomes a central axis that partially coincides with the normal line of the extension portion, or can be inclined so that the normal line and the central axis coincide with each other. Crystal pulling device.   6. The apparatus for pulling down a single crystal according to claim 5, further comprising a seed touch surface driving unit capable of moving the seed holder in parallel with the extending portion of the crucible.

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