WO2017126594A1 - Die pack, sapphire single-crystal growing device, and sapphire single-crystal growing method - Google Patents

Die pack, sapphire single-crystal growing device, and sapphire single-crystal growing method Download PDF

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WO2017126594A1
WO2017126594A1 PCT/JP2017/001702 JP2017001702W WO2017126594A1 WO 2017126594 A1 WO2017126594 A1 WO 2017126594A1 JP 2017001702 W JP2017001702 W JP 2017001702W WO 2017126594 A1 WO2017126594 A1 WO 2017126594A1
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die pack
sapphire single
die
crystal
single crystal
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PCT/JP2017/001702
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French (fr)
Japanese (ja)
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弘倫 斎藤
古滝　敏郎
数人 樋口
佐藤　次男
矢口　洋一
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並木精密宝石株式会社
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    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B15/00—Single-crystal growth by pulling from a melt, e.g. Czochralski method
    • C30B15/20—Controlling or regulating
    • C30B15/22—Stabilisation or shape controlling of the molten zone near the pulled crystal; Controlling the section of the crystal
    • C30B15/24—Stabilisation or shape controlling of the molten zone near the pulled crystal; Controlling the section of the crystal using mechanical means, e.g. shaping guides
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/16—Oxides
    • C30B29/20—Aluminium oxides

Definitions

  • the present invention relates to a die pack, a sapphire single crystal growing apparatus, and a method for growing a sapphire single crystal.
  • the Czochralski (CZ) method As a method for growing a single crystal, the Czochralski (CZ) method, the heat exchange (HEM) method, the Bernoulli method, the edge defined film fed growth (EFG) method and the like are known.
  • the EFG method is known as the only method for producing a flat single crystal.
  • the EFG method is a crystal manufacturing method that has a very high utility value when manufacturing a single crystal having a predetermined crystal orientation.
  • a sapphire single crystal grown using the EFG method requires less man-hours for processing a thin plate-like substrate. Since it can be reduced, it is used in various applications including an epitaxial growth substrate of a blue light emitting element.
  • Patent Document 1 is known as a mass production method of sapphire single crystals using the EFG method.
  • Patent Document 1 discloses a sapphire single crystal manufacturing method and a die pack for growing a plurality of single crystal materials from a single seed crystal.
  • Patent Document 2 discloses a manufacturing method and a manufacturing apparatus for a sapphire ribbon using the EFG method.
  • FIG. 2 shows the form of a die in which the height of the die is changed from the center toward the outside.
  • the present applicants have conventionally produced sapphire single crystals using the EFG method.
  • the applicants have been considering increasing the crucible diameter and die pack to increase the number of growth.
  • simply increasing the number of dies has caused a problem that crystal defects and thinning of the crystal outline occur, resulting in large variations in crystal quality. This variation was particularly noticeable in the center and outside grown crystals of the die pack, and it was thought that this variation was caused by a temperature gradient in the number of die packs.
  • the present invention has been made in view of the above problems, a die pack capable of suppressing variation in crystal quality of a sapphire single crystal and improving mass productivity, a sapphire single crystal growth apparatus using the die pack, and sapphire
  • An object is to provide a method for growing a single crystal.
  • the present inventors have found a step shape of a die pack that can suppress variation in crystal quality and improve mass productivity from the results of the growth test. Furthermore, the present invention has been completed by finding a method for quickly determining the step shape of the die pack according to the size of the grown crystal. That is,
  • a die pack used for growing a sapphire single crystal by the EFG method according to the present invention is: It has a step H with respect to the lowest die height in the die pack at a distance x from the center of the die pack, and this step H is defined by a function of the second order to the fourth order of x.
  • this function is 2nd order to 4th order of x
  • the step H at the center of the die pack is c
  • the sapphire single crystal growing apparatus according to the present invention is characterized by using the die pack described in any one of (1) to (3) above.
  • the method for growing a sapphire single crystal according to the present invention is characterized by using the die pack described in any one of (1) to (3) above.
  • a die pack capable of suppressing variation in crystal quality of a sapphire single crystal and improving mass productivity, a sapphire single crystal growing apparatus using the die pack, and a method for growing a sapphire single crystal. Can do.
  • the level difference of the die pack can be determined without taking a long time and cost.
  • FIG. 1 It is a figure which shows typically the several sapphire single crystal obtained by this invention. It is a graph which shows the result of the present Example 1 and the comparative example 1. FIG. It is a graph which shows the result of the present Example 2 and the comparative example 2. FIG. It is a graph which shows the result of the present Example 3 and the comparative example 3. FIG. It is a graph which shows the result of the present Example 4 and the comparative example 4.
  • FIG. 1 shows an example of a die pack according to the present invention.
  • the “die” (101) described in the present specification refers to one constituted by a pair of partition plates (201, 201).
  • the “die pack” (102) refers to a plurality of sets of the dies 101 arranged so as to face each other so that their slits are parallel to each other.
  • the opposing partition plates 201 have the same flat plate shape and are arranged in parallel so as to form a minute gap (slit 202).
  • the raw material melt is guided to the upper part of the die through the minute gap to form the raw material melt surface.
  • x means an absolute value. That is, the step H preferably changes in a curve with respect to x, and among them, it is preferable to have a configuration that changes in a quadratic function, a cubic function, or a quartic function. This was derived as a result of the growth test conducted by the present inventors actually preparing several types of die packs, and the width, thickness, number of the grown crystals, the size of the die pack, the size of the crucible, etc. Is not.
  • the “step H” is the difference between the lowest die height h1 in the die pack and the other die heights h2 excluding the lowest die.
  • the step H is measured at the same position on the upper surface of the die (for example, the points indicated by the arrows h1 and h2 in FIG. 1). Whether the shape of the upper surface of the die is V-shaped as shown in FIG. 1 or a horizontal surface, the difference between the same positions on the upper surface of the die is taken. Further, the step H is measured on the side surface of the die, and the shape in the width direction of the die is not particularly limited.
  • the step H By configuring the step H to be a function of the second order to the fourth order of x, the temperature gradient at the center and the outside of the die pack becomes more gradual, so that variations in crystal quality can be suppressed. If the curve is a function of fifth order or higher, a good temperature gradient cannot be obtained particularly near the center of the die pack, which is not preferable.
  • the center of the die pack and the outermost step H are as follows: It is preferable that the configuration satisfies the conditions.
  • a die pack having a length L and a width W is installed in a crucible having a diameter ⁇ as shown in FIG. In this case, as shown in FIG.
  • the center of the die pack and the outermost step H which are particularly important in the initial design of the die pack can be quickly determined. This technique was verified by the present inventors based on the results of the growth test, and found to efficiently produce sapphire single crystals of all sizes.
  • the coefficients a, b, and c are obtained by the following procedure.
  • a die pack having a length L and a width W is installed in a crucible having a diameter ⁇ .
  • the step H can be obtained by calculation using simple parameters such as the crucible diameter ⁇ , the die pack length L, and the die pack width W. Further, the step shape obtained by the above calculation formula may be used as an initial design without making the final shape. That is, as a result of performing a growth test using an initially designed die pack and finely adjusting the level difference from the state of the grown crystal, the curve of the level difference may finally become a quadratic function or a quartic function.
  • the standard step shape is shown, so it is possible to greatly reduce the number of times even if a growth test is necessary, and it has an effect on both time and cost .
  • the step shape of the die pack can be determined without taking a long time and cost, mass production of sapphire single crystals and sapphire substrates without variations in crystal quality becomes possible.
  • the die pack can be easily designed.
  • the die pack of the present invention can be applied to single crystals other than sapphire as long as it is used in the EFG method.
  • the material of the die pack of the present invention is preferably a refractory metal molybdenum or an alloy of molybdenum suitable for use at a high temperature exceeding 2000 ° C. during sapphire single crystal growth.
  • the diameter ⁇ of the crucible in which the die pack of the present invention is installed is desirably 150 mm or more and 500 mm or less for practical use in mass production.
  • the length L of the die pack is desirably 30% or more and 80% or less of the crucible diameter. If it is set to 30% or less, the number of cultivated sheets decreases, resulting in poor mass production efficiency. If it is set to 80% or more, it is difficult to obtain a stable die pack temperature distribution, which is not preferable.
  • the width W and the length in the diagonal direction of the die pack are desirably 30% to 80% of the crucible diameter.
  • the thickness t of the die 101 corresponding to the thickness of the grown crystal is preferably 1 mm or more and 10 mm or less.
  • the thickness t is preferably 1 mm or more and 10 mm or less.
  • the number of sets of dies 101 corresponding to the number of grown crystals is preferably 2 or more and 80 or less.
  • the number of grown crystals is limited by the above-described die pack length L and thickness t. However, considering the mass productivity, it is preferable because the temperature balance adjustment in the number direction becomes difficult when the number exceeds 80. Absent.
  • the sapphire single crystal manufacturing apparatus 3 includes a growth container 4 for growing a sapphire single crystal and a pulling container 5 for pulling up the grown sapphire single crystal, and a plurality of sapphire single crystals by the EFG method.
  • Crystal 20 (hereinafter simply referred to as sapphire single crystal 20) is grown.
  • the growth container 4 includes a crucible 6, a crucible driving unit 7, a heater 8, an electrode 9, a die pack 102, and a heat insulating material 10.
  • the crucible 6 is made of molybdenum or an alloy of molybdenum and melts the aluminum oxide raw material.
  • the crucible drive unit 7 rotates the crucible 6 with the vertical direction as an axis.
  • the heater 8 heats the crucible 6.
  • the electrode 9 energizes the heater 8.
  • the die pack 102 is installed in the crucible 6 and determines the liquid surface shape of the aluminum oxide melt (hereinafter simply referred to as “melt” as necessary) when pulling up the sapphire single crystal.
  • the heat insulating material 10 surrounds the crucible 6, the heater 8, and the die pack 102.
  • the growth container 4 includes an atmospheric gas inlet 11 and an exhaust 12.
  • the atmosphere gas introduction port 11 is an introduction port for introducing, for example, argon gas into the growth vessel 4 as the atmosphere gas, and prevents oxidation of the crucible 6, the heater 8, and the die pack 102.
  • the exhaust port 12 is provided for exhausting the inside of the growth vessel 4.
  • the pulling container 5 includes a shaft 13, a shaft driving unit 14, a gate valve 15, and a substrate inlet / outlet 16, and pulls up a plurality of sapphire single crystals 20 grown from the seed crystal 21.
  • the shaft 13 holds the seed crystal 21.
  • the shaft driving unit 14 moves the shaft 13 up and down toward the crucible 6 and rotates the shaft 13 around the lifting direction.
  • the gate valve 15 partitions the growth container 4 and the pulling container 5.
  • the substrate entrance / exit 16 takes in and out the seed crystal 21.
  • the manufacturing apparatus 3 also has a control unit (not shown), and the rotation of the crucible drive unit 7 and the shaft drive unit 14 is controlled by this control unit.
  • a method for manufacturing the sapphire single crystal 20 using the manufacturing apparatus 3 will be described with reference to FIGS.
  • a predetermined amount of agglomerated aluminum oxide raw material powder (99.99% aluminum oxide), which is a raw material of sapphire single crystal, is charged into a crucible 6 in which a die pack 102 is housed.
  • the aluminum oxide raw material powder may contain compounds and elements other than aluminum oxide depending on the purity or composition of the sapphire single crystal to be produced.
  • the inside of the growth vessel 4 is replaced with argon gas, and the oxygen concentration is set to a predetermined value or less.
  • the crucible 6 is heated to a predetermined temperature by the heater 8 to melt the aluminum oxide raw material powder. Since the melting point of aluminum oxide is about 2050 ° C. to 2072 ° C., the heating temperature of the crucible 6 is set to a temperature higher than the melting point (for example, 2100 ° C.). After a while after heating, the raw material powder melts and an aluminum oxide melt 17 is prepared. As shown in FIG. 5A, a part of the melt ascends through the slit 202 of the die due to capillary action and reaches the surface of the die pack 102, and the melt pool 18 is formed above the slit.
  • the lower end of the seed crystal 21 is the melt of all the dies. Lower until it contacts the melt surface of the reservoir 18.
  • the seed crystal 21 is previously introduced into the pulling container 5 from the substrate entrance 16.
  • the shape of the seed crystal 21 shown in FIGS. 5A and 5B is an example.
  • the plane direction of the seed crystal 21 and the longitudinal direction of the die pack 102 so as to be orthogonal to each other at an angle of 90 °, it is possible to simultaneously grow a plurality of sapphire single crystals from one seed crystal. It becomes. Therefore, the plane direction of the grown sapphire single crystal 20 is also orthogonal to the plane direction of the seed crystal 21 at an angle of 90 °.
  • the neck portion 22 is formed as shown in FIG. Specifically, first, a thin neck portion 22 is produced (necked) while the substrate holder is raised at high speed by the shaft 13. Hereinafter, this process is referred to as a necking process.
  • the heater 8 is controlled to lower the temperature of the crucible 6, and the ascent rate of the substrate holder is set to a predetermined rate, and the sapphire single crystal 20 is centered on the seed crystal 21 and the width of the die pack. Crystal growth is performed so as to widen in the direction (spraying process).
  • the growth of the straight body portion 23 having a crystal width defined by the width W of the die pack is started (straight body process).
  • the straight body process a plurality of sapphire single crystals 20 having a straight body portion defined by side surfaces that are substantially parallel to and opposed to each other are manufactured.
  • the length of the straight body is not particularly limited, it is preferably 2 inches or more (50.8 mm or more).
  • the sapphire single crystal 20 as shown in FIG. 6 is obtained through the above-described necking process, spraying process, and straight body process.
  • the obtained sapphire single crystal 20 is allowed to cool, the gate valve 15 is opened, the sapphire single crystal 20 is moved to the pulling container 5 side, and taken out from the substrate entrance 16.
  • the crystal plane of the main surface of the sapphire single crystal 20 can be arbitrarily changed by arbitrarily setting the crystal plane of the seed crystal 21.
  • the main surface of the sapphire single crystal 20 is not limited to the a-plane, and can be set to a desired crystal plane such as a c-plane, r-plane, or m-plane.
  • the sapphire single crystal 20 grown using the die pack of the present invention has a seed crystal and at least a straight body portion, and the lower end of the straight body portion corresponds to the step H of each die. It has a step shape. Further, since crystal growth is performed in a state where the temperature gradient of the die pack is good, a thin sapphire single crystal having a uniform growth crystal width and thickness is obtained without thinning of the crystal shape in the straight body portion.
  • the straight body portion has no crystal defects” means that the crystal defects as described above do not exist in the region used for substrate processing in the straight body portion of the grown crystal. Specifically, it means that there is no crystal defect in a region within 95% of the width of the grown crystal.
  • the sapphire single crystal 20 having no variation in crystal quality can be manufactured from the common seed crystal 21, so that the mass productivity of the sapphire single crystal is improved. It becomes possible. Since the sapphire single crystal thus obtained can be polished to provide a sapphire substrate, the mass productivity of the sapphire substrate can be improved.
  • a die pack 102 shown as an example in FIG. 1 and a sapphire single crystal manufacturing apparatus shown in FIG. 4 a plurality of sapphire single crystals 20 having a c-plane as a main surface were manufactured by the method described above.
  • Table 1 shows the conditions of the length L and width W of the die pack used in Examples 1 to 4 and the diameter ⁇ of the crucible.
  • the step H of the die pack in which the best growth was performed without causing crystal defects and thinning of the crystal outline was plotted with ⁇ marks. 7 to 10 are shown.
  • Comparative Examples 1 to 4 in Table 2 show coefficients a, c, and d obtained by the method described above using the same L, W, and ⁇ conditions as in Examples 1 to 4. Curves obtained by adjusting the coefficient b are shown in FIGS.

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  • Engineering & Computer Science (AREA)
  • Crystallography & Structural Chemistry (AREA)
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Abstract

[Problem] To provide a die pack which is used for growing sapphire single crystals by EFG and in which a height difference H in the plate alignment direction is swiftly determined in order to suppress variation in the crystalline quality of the sapphire single crystals and achieve increased productivity, and also to provide a sapphire single-crystal growing device and a sapphire single-crystal growing method using the same. [Solution] This die pack has, at a distance x from the center thereof, a height difference H relative to a die of the lowest height in the die pack, where said height difference H is defined by a second-order to fourth-order function of x.

Description

ダイパック、サファイア単結晶育成装置、およびサファイア単結晶の育成方法Die pack, sapphire single crystal growing apparatus, and sapphire single crystal growing method
　本発明は、ダイパック、サファイア単結晶育成装置、およびサファイア単結晶の育成方法に関する。 The present invention relates to a die pack, a sapphire single crystal growing apparatus, and a method for growing a sapphire single crystal.
　従来、単結晶を成長させる方法として、チョクラルスキー（ＣＺ）法、ヒートエクスチェンジ（ＨＥＭ）法、ベルヌイ法、エッジデファインド・フィルムフェッド・グロース（ＥＦＧ）法などが知られている。このうち、平板形状の単結晶を製造する方法としてはＥＦＧ法が唯一の方法として知られている。ＥＦＧ法は、所定の結晶方位を有する単結晶を製造する場合に極めて利用価値が高い結晶製造方法であり、ＥＦＧ法を用いて育成されたサファイア単結晶は、薄板状の基板加工への工数を減らすことができるという利点があることから、青色発光素子のエピタキシャル成長基板をはじめとする様々な用途に用いられている。 Conventionally, as a method for growing a single crystal, the Czochralski (CZ) method, the heat exchange (HEM) method, the Bernoulli method, the edge defined film fed growth (EFG) method and the like are known. Of these, the EFG method is known as the only method for producing a flat single crystal. The EFG method is a crystal manufacturing method that has a very high utility value when manufacturing a single crystal having a predetermined crystal orientation. A sapphire single crystal grown using the EFG method requires less man-hours for processing a thin plate-like substrate. Since it can be reduced, it is used in various applications including an epitaxial growth substrate of a blue light emitting element.
　ＥＦＧ法を用いたサファイア単結晶の量産方法として、特許文献１が知られている。特許文献１には、一枚の種結晶から複数枚の単結晶材を育成するサファイア単結晶の製造方法とダイパックが開示されている。 Patent Document 1 is known as a mass production method of sapphire single crystals using the EFG method. Patent Document 1 discloses a sapphire single crystal manufacturing method and a die pack for growing a plurality of single crystal materials from a single seed crystal.
　特許文献２には、ＥＦＧ法を用いたサファイアリボンの製造方法および製造装置が開示されている。Ｆｉｇ．２には、中央から外側に向かってダイの高さを変化させたダイの形態が示されている。 Patent Document 2 discloses a manufacturing method and a manufacturing apparatus for a sapphire ribbon using the EFG method. FIG. 2 shows the form of a die in which the height of the die is changed from the center toward the outside.
特許第４４６５４８１号公報Japanese Patent No. 4465481 米国特許公報２０１４／２７２４１３号公報US Patent Publication No. 2014/272413
　本出願人らは、従来からＥＦＧ法を用いたサファイア単結晶の生産を行っていたが、さらに量産性を高めるため、坩堝径とダイパックを大型化し育成枚数を増やすことを検討していた。しかしながら、単にダイの枚数を増やしただけでは、結晶欠陥や結晶外形の細りが発生し、結晶品質のばらつきが大きくなることが問題となっていた。このばらつきは、特にダイパックの中心と外側の育成結晶において顕著であることから、ダイパックの枚数方向の温度勾配に起因していると考えられた。 The present applicants have conventionally produced sapphire single crystals using the EFG method. However, in order to further increase mass productivity, the applicants have been considering increasing the crucible diameter and die pack to increase the number of growth. However, simply increasing the number of dies has caused a problem that crystal defects and thinning of the crystal outline occur, resulting in large variations in crystal quality. This variation was particularly noticeable in the center and outside grown crystals of the die pack, and it was thought that this variation was caused by a temperature gradient in the number of die packs.
　このようなＥＦＧ法特有の問題に対して、特許文献２のようにダイの高さを変化させる方法が開示されているが、あらゆるサイズの育成結晶に対応できる何らかの法則性を提供するものではなかった。一方、量産性を向上させるためには、あらゆるサイズ、すなわち、結晶幅や厚みの異なるサファイア単結晶を、坩堝径を最大限に生かした枚数で効率良く生産する必要がある。従来、このダイの高さは、育成試験を繰り返すことによって決定していたため、長い時間とコストがかかっていた。 To solve such a problem peculiar to the EFG method, a method for changing the height of the die as disclosed in Patent Document 2 is disclosed, but it does not provide any kind of law that can handle grown crystals of all sizes. It was. On the other hand, in order to improve mass productivity, it is necessary to efficiently produce sapphire single crystals of all sizes, that is, crystal widths and thicknesses, with the maximum number of crucible diameters. Conventionally, the height of this die has been determined by repeating the growth test, which has taken a long time and cost.
　本発明は、上記課題に鑑みてなされたものであり、サファイア単結晶の結晶品質のばらつきを抑え、量産性を向上させることが可能なダイパックと、これを用いたサファイア単結晶育成装置、およびサファイア単結晶の育成方法を提供することを目的とする。 The present invention has been made in view of the above problems, a die pack capable of suppressing variation in crystal quality of a sapphire single crystal and improving mass productivity, a sapphire single crystal growth apparatus using the die pack, and sapphire An object is to provide a method for growing a single crystal.
　本発明者らは、育成試験の結果から、結晶品質のばらつきを抑え、量産性を向上できるダイパックの段差形状を見出した。さらに、育成結晶のサイズに応じたダイパックの段差形状を迅速に決定する手法を見出し、本発明を完成させた。すなわち、 The present inventors have found a step shape of a die pack that can suppress variation in crystal quality and improve mass productivity from the results of the growth test. Furthermore, the present invention has been completed by finding a method for quickly determining the step shape of the die pack according to the size of the grown crystal. That is,
　（１）本発明に係るＥＦＧ法によるサファイア単結晶の育成に使用するダイパックは、
ダイパックの中心からの距離ｘにおいて、ダイパック中で最も低いダイ高さに対する段差Ｈを有し、この段差Ｈが、ｘの2次以上４次以下の関数で規定されることを特徴とする。 (1) A die pack used for growing a sapphire single crystal by the EFG method according to the present invention is:
It has a step H with respect to the lowest die height in the die pack at a distance x from the center of the die pack, and this step H is defined by a function of the second order to the fourth order of x.
　（２）また、本発明に係るダイの一実施形態は、この関数が、ｘの2次以上４次以下であり、かつ、ダイパックの中心における段差Ｈをｃ、ダイパックの最も外側における段差Ｈをｄとし、ダイパックの幅、長さ、坩堝の直径をそれぞれＷ、Ｌ、φとしたとき、ｃは、ｃ＝Ｌ／Ｗ／４、ｄは、
Figure JPOXMLDOC01-appb-M000002
 を満たすことを特徴とする。 (2) Further, in one embodiment of the die according to the present invention, this function is 2nd order to 4th order of x, and the step H at the center of the die pack is c, and the step H at the outermost side of the die pack is where d is the width, length of the die pack, and the diameter of the crucible is W, L, and φ, respectively, c is c = L / W / 4, d is
Figure JPOXMLDOC01-appb-M000002
 It is characterized by satisfying.
　（３）また、本発明に係るダイパックの別の実施形態は、この関数が、Ｈ=ａｘ3＋ｂｘ2＋ｃであり、ａは、ａ＝Ｌ／Ｗ／１００、ｃは、ｃ＝Ｌ／Ｗ／４を満たし、かつ、ｂが、ｄを満たすように最小二乗法により求められた係数であることを特徴とする。 (3) In another embodiment of the die pack according to the present invention, this function is H = ax 3 + bx 2 + c, a is a = L / W / 100, and c is c = L / W / 4 is satisfied, and b is a coefficient obtained by the least square method so as to satisfy d.
　（４）また、本発明に係るサファイア単結晶の育成装置は、上記（１）～（３）のいずれかに記載のダイパックを用いることを特徴とする。 (4) Further, the sapphire single crystal growing apparatus according to the present invention is characterized by using the die pack described in any one of (1) to (3) above.
　（５）また、本発明に係るサファイア単結晶の育成方法は、上記（１）～（３）のいずれかに記載のダイパックを使用することを特徴とする。 (5) Further, the method for growing a sapphire single crystal according to the present invention is characterized by using the die pack described in any one of (1) to (3) above.
　本発明によれば、サファイア単結晶の結晶品質のばらつきを抑え、量産性を向上させることが可能なダイパックと、これを用いたサファイア単結晶育成装置、およびサファイア単結晶の育成方法を提供することができる。また、長い時間やコストをかけることなくダイパックの段差を決定できる。 According to the present invention, there are provided a die pack capable of suppressing variation in crystal quality of a sapphire single crystal and improving mass productivity, a sapphire single crystal growing apparatus using the die pack, and a method for growing a sapphire single crystal. Can do. In addition, the level difference of the die pack can be determined without taking a long time and cost.
本発明に係るダイパックを説明する図である。It is a figure explaining the die pack which concerns on this invention. 本発明に係るダイパックの距離ｘと段差Ｈの関係を示すグラフである。It is a graph which shows the relationship between the distance x and level | step difference H of the die pack which concerns on this invention. ＥＦＧ法の坩堝とダイパックを示す概略構成図である。It is a schematic block diagram which shows the crucible and die pack of an EFG method. ＥＦＧ法によるサファイア単結晶製造装置を示す概略構成図である。It is a schematic block diagram which shows the sapphire single-crystal manufacturing apparatus by EFG method. (ａ) 本発明の実施形態における種結晶とダイおよびダイパックの位置関係を模式的に示す図である。(ｂ) 本発明の実施形態における、種結晶の一部を溶融する様子を示す説明図である。 (ｃ) 本発明の実施形態における、ネッキング工程およびスプレーディング工程を示す図である。(a) A diagram schematically showing the positional relationship between a seed crystal, a die and a die pack in an embodiment of the present invention. (b) It is explanatory drawing which shows a mode that a part of seed crystal is fuse | melted in embodiment of this invention. (C) 図 is a diagram showing a necking step and a spraying step in the embodiment of the present invention. 本発明により得られる複数枚のサファイア単結晶を模式的に示す図である。It is a figure which shows typically the several sapphire single crystal obtained by this invention. 本実施例１および比較例１の結果を示すグラフである。It is a graph which shows the result of the present Example 1 and the comparative example 1. FIG. 本実施例２および比較例２の結果を示すグラフである。It is a graph which shows the result of the present Example 2 and the comparative example 2. FIG. 本実施例３および比較例３の結果を示すグラフである。It is a graph which shows the result of the present Example 3 and the comparative example 3. FIG. 本実施例４および比較例４の結果を示すグラフである。It is a graph which shows the result of the present Example 4 and the comparative example 4. FIG.
　図１に本発明に係るダイパックの一例を示す。本明細書中で記載する「ダイ」（１０１）とは、一対の仕切り板（２０１，２０１）によって構成されるものを呼ぶものとする。そして「ダイパック」（１０２）とは、前記ダイ１０１が複数組互いのスリットが平行になるように対向配置したものを呼ぶものとする。 FIG. 1 shows an example of a die pack according to the present invention. The “die” (101) described in the present specification refers to one constituted by a pair of partition plates (201, 201). The “die pack” (102) refers to a plurality of sets of the dies 101 arranged so as to face each other so that their slits are parallel to each other.
　ダイ１０１において、対向する仕切り板２０１は同一の平板形状を有し、微少間隙（スリット２０２）を形成するように平行に配置されている。原料溶融液は、該微小間隙を伝ってダイ上部に導かれ、原料溶融液面を形成する。 In the die 101, the opposing partition plates 201 have the same flat plate shape and are arranged in parallel so as to form a minute gap (slit 202). The raw material melt is guided to the upper part of the die through the minute gap to form the raw material melt surface.
　図１に示すように、本発明のダイパックは、ダイパックの中心（ｘ＝０）からの距離ｘにおいて、ダイパック中で最も低いダイ高さに対する段差Ｈを有し、この段差Ｈが、ｘの2次以上４次以下の関数で規定されるように構成される。以下の説明では、ｘとは絶対値のことを意味するものとする。すなわち、段差Ｈは、ｘに対して曲線的に変化するのが好ましく、その中でも、２次関数、３次関数、又は４次関数的に変化する構成とするのが好ましい。これは、本発明者らが実際に数種類のダイパックを準備して行った育成試験の結果導出されたものであり、育成結晶の幅、厚み、枚数やダイパックの大きさ、坩堝の大きさ等にはよらないものである。 As shown in FIG. 1, the die pack of the present invention has a step H with respect to the lowest die height in the die pack at a distance x from the center (x = 0) of the die pack. It is configured so as to be defined by a function of order 4 or more and order 4 or less. In the following description, x means an absolute value. That is, the step H preferably changes in a curve with respect to x, and among them, it is preferable to have a configuration that changes in a quadratic function, a cubic function, or a quartic function. This was derived as a result of the growth test conducted by the present inventors actually preparing several types of die packs, and the width, thickness, number of the grown crystals, the size of the die pack, the size of the crucible, etc. Is not.
　「段差Ｈ」とは、図１に例示するように、ダイパック中で最も低いダイ高さｈ１と、最も低いダイを除くその他のダイ高さｈ２との差である。なお、図１では一例として、ｘ＝０においてダイ高さが最も低いダイパックを示しているが、後述する実施例及び比較例の結果を示す図７～１０を見ると分かるように、ダイ高さが最も低くなる位置が必ずしもダイパックの中心、すなわちｘ＝０の位置になるとは限らない。また、段差Ｈは、ダイの上面の同じ位置同士（例えば図１中、ｈ１およびｈ２の矢印が示す点）で計測されるものとする。ダイの上面の形状が図１のようにＶ字型であっても、あるいは水平面であっても、ダイの上面の同じ位置同士での差をとるものとする。また、段差Ｈは、ダイの側面で計測されるものとし、ダイの幅方向の形状は特に限定されない。 As shown in FIG. 1, the “step H” is the difference between the lowest die height h1 in the die pack and the other die heights h2 excluding the lowest die. As an example, FIG. 1 shows a die pack having the lowest die height at x = 0. However, as can be seen from FIGS. 7 to 10 showing the results of Examples and Comparative Examples described later, the die height is shown. Is not necessarily the center of the die pack, that is, the position of x = 0. Further, the step H is measured at the same position on the upper surface of the die (for example, the points indicated by the arrows h1 and h2 in FIG. 1). Whether the shape of the upper surface of the die is V-shaped as shown in FIG. 1 or a horizontal surface, the difference between the same positions on the upper surface of the die is taken. Further, the step H is measured on the side surface of the die, and the shape in the width direction of the die is not particularly limited.
　段差Ｈをｘの２次以上４次以下の関数となるように構成することによって、ダイパックの中心と外側での温度勾配がより緩やかになるため、結晶品質のばらつきを抑えることができる。曲線が５次以上の関数になると、特にダイパックの中心付近において良好な温度勾配が得られないため、好ましくない。 By configuring the step H to be a function of the second order to the fourth order of x, the temperature gradient at the center and the outside of the die pack becomes more gradual, so that variations in crystal quality can be suppressed. If the curve is a function of fifth order or higher, a good temperature gradient cannot be obtained particularly near the center of the die pack, which is not preferable.
　さらに、本発明者らの育成試験による検証によれば、段差Ｈが、ｘの2次以上４次以下の関数で規定されることに加えて、ダイパックの中心と最も外側の段差Ｈが以下の条件を満たす構成とするのが好ましい。図３に示すように、直径φの坩堝の中に、長さＬ、幅Ｗを有するダイパックを設置する場合を考える。この場合、ダイパックの中心からの距離ｘと段差Ｈとの関係は、図２に示すように、ｘの2次以上４次以下の関数で規定されることに加えて、ダイパックの中心（ｘ＝０）における段差ｃ、およびダイパックの最も外側（ｘ＝Ｌ／２）における段差ｄが、
ｃ＝Ｌ／Ｗ／４、および
Figure JPOXMLDOC01-appb-M000003
 を満たす構成とするのが好ましい。 Further, according to the verification by the inventors' growth test, in addition to the step H being defined by a function of the second order to the fourth order of x, the center of the die pack and the outermost step H are as follows: It is preferable that the configuration satisfies the conditions. Consider a case where a die pack having a length L and a width W is installed in a crucible having a diameter φ as shown in FIG. In this case, as shown in FIG. 2, the relationship between the distance x from the center of the die pack and the step H is defined by a function of the second order to the fourth order of x, and in addition to the center of the die pack (x = 0) and the step d on the outermost side of the die pack (x = L / 2)
c = L / W / 4, and
Figure JPOXMLDOC01-appb-M000003
 It is preferable that the configuration satisfies the above.
　このような構成とすることによって、結晶品質のばらつきを抑えるという効果に加え、ダイパックの初期設計で特に重要となるダイパックの中心と最も外側の段差Ｈを迅速に決定できる。この手法は、本発明者らが育成試験の結果をもとに検証し、あらゆるサイズのサファイア単結晶を効率良く生産するために見出した手法である。 With such a configuration, in addition to the effect of suppressing variation in crystal quality, the center of the die pack and the outermost step H which are particularly important in the initial design of the die pack can be quickly determined. This technique was verified by the present inventors based on the results of the growth test, and found to efficiently produce sapphire single crystals of all sizes.
　さらに本発明者らの検証によれば、ダイパックの中心と最も外側の段差Ｈを上記の構成とすることに加え、段差Ｈが、Ｈ＝ａｘ3＋ｂｘ2＋ｃを満たす構成とするのが最も好ましい。本発明者らが見出した手法によれば、係数であるａ, ｂ, ｃは以下の手順で求められる。 Further, according to the verification by the present inventors, in addition to the above-described configuration of the die pack center and the outermost step H, it is most preferable that the step H has a configuration satisfying H = ax 3 + bx 2 + c. . According to the technique found by the present inventors, the coefficients a, b, and c are obtained by the following procedure.
　図３に示すように、直径φの坩堝の中に、長さＬ、幅Ｗを有するダイパックを設置するものとする。このとき、係数ａはａ= Ｌ／Ｗ／１００として求めることができる。係数ｃは上述したようにｃ＝Ｌ／Ｗ／４として求めることができる。ここで、係数ｂは、ダイパックの最も外側（ｘ＝Ｌ／２）において段差Ｈ＝ｄを満たすように最小二乗法によって調整された値となる。 As shown in FIG. 3, a die pack having a length L and a width W is installed in a crucible having a diameter φ. At this time, the coefficient a can be obtained as a = L / W / 100. The coefficient c can be obtained as c = L / W / 4 as described above. Here, the coefficient b is a value adjusted by the least square method so as to satisfy the step H = d on the outermost side (x = L / 2) of the die pack.
　以上述べたように、本発明のダイパックは、段差Ｈを、坩堝の直径φ、ダイパックの長さＬ、ダイパックの幅Ｗといった簡単なパラメータを用いて計算により求めることが可能である。また、上記計算式により求められた段差形状を最終形状とせず、初期設計として用いてもよい。すなわち、初期設計のダイパックを用いて育成試験を行い、育成結晶の状態から段差を微調整した結果、段差の曲線が最終的に２次関数や４次関数になってもよい。上記計算式を用いた初期設計を行うことにより、目安となる段差形状が示されるため、育成試験が必要な場合でも大幅にその回数を減らすことが可能となり、時間とコストの両方に対する効果を有する。 As described above, in the die pack of the present invention, the step H can be obtained by calculation using simple parameters such as the crucible diameter φ, the die pack length L, and the die pack width W. Further, the step shape obtained by the above calculation formula may be used as an initial design without making the final shape. That is, as a result of performing a growth test using an initially designed die pack and finely adjusting the level difference from the state of the grown crystal, the curve of the level difference may finally become a quadratic function or a quartic function. By performing the initial design using the above calculation formula, the standard step shape is shown, so it is possible to greatly reduce the number of times even if a growth test is necessary, and it has an effect on both time and cost .
　本発明によれば、長い時間やコストをかけることなく、ダイパックの段差形状を決定できるため、結晶品質のばらつきのないサファイア単結晶およびサファイア基板の量産が可能になる。さらに、ダイパックの設計が容易になるという効果をも有する。本発明のダイパックは、ＥＦＧ法で用いるものであればサファイア以外の単結晶にも適用できる。 According to the present invention, since the step shape of the die pack can be determined without taking a long time and cost, mass production of sapphire single crystals and sapphire substrates without variations in crystal quality becomes possible. In addition, the die pack can be easily designed. The die pack of the present invention can be applied to single crystals other than sapphire as long as it is used in the EFG method.
　本発明のダイパックの材質は、サファイア単結晶育成時において２０００℃を超える高温下での使用に適している高融点金属のモリブデン又はモリブデンの合金が好ましい。 The material of the die pack of the present invention is preferably a refractory metal molybdenum or an alloy of molybdenum suitable for use at a high temperature exceeding 2000 ° C. during sapphire single crystal growth.
　本発明のダイパックを設置する坩堝の直径φは、量産への実用上、１５０ｍｍ以上５００ｍｍ以下であることが望ましい。 The diameter φ of the crucible in which the die pack of the present invention is installed is desirably 150 mm or more and 500 mm or less for practical use in mass production.
　本発明のダイパックにおいて、ダイパックの長さＬは、坩堝直径の３０％以上８０％以下であることが望ましい。３０％以下に設定すると育成枚数が少なくなるため量産効率が悪くなり、８０％以上に設定すると安定したダイパックの温度分布が得られにくいため好ましくない。 In the die pack of the present invention, the length L of the die pack is desirably 30% or more and 80% or less of the crucible diameter. If it is set to 30% or less, the number of cultivated sheets decreases, resulting in poor mass production efficiency. If it is set to 80% or more, it is difficult to obtain a stable die pack temperature distribution, which is not preferable.
　上記と同様の理由により、ダイパックの幅Ｗおよび対角方向の長さも、坩堝直径の３０％以上８０％以下であることが望ましい。 For the same reason as described above, the width W and the length in the diagonal direction of the die pack are desirably 30% to 80% of the crucible diameter.
　図１に示すように、育成結晶の厚みに対応するダイ１０１の厚みｔは、１ｍｍ以上１０ｍｍ以下とすることが望ましい。厚みｔを１ｍｍ以上とすることで、育成されたサファイア単結晶自身の強度と自立性を確保することができる。さらに、サファイア基板に加工する場合でも、十分な加工しろを確保することができる。また、厚みｔが１０ｍｍを超えると結晶品質に優れたサファイア単結晶を得ることが困難となるため、１０ｍｍ以下とするのが好ましい。 As shown in FIG. 1, the thickness t of the die 101 corresponding to the thickness of the grown crystal is preferably 1 mm or more and 10 mm or less. By setting the thickness t to 1 mm or more, the strength and self-supporting property of the grown sapphire single crystal itself can be ensured. Furthermore, even when processing into a sapphire substrate, a sufficient processing margin can be ensured. Moreover, since it will become difficult to obtain the sapphire single crystal excellent in crystal quality when thickness t exceeds 10 mm, it is preferable to set it as 10 mm or less.
　また本発明のダイパックにおいて、育成結晶の枚数に対応するダイ１０１の組数は、２以上８０以下とすることが好ましい。育成結晶の枚数は、上述したダイパック長さＬおよび厚みｔによって制限を受けるものであるが、量産性を考慮しても、その数が８０を超えると枚数方向の温度バランス調整が難しくなるため好ましくない。 In the die pack of the present invention, the number of sets of dies 101 corresponding to the number of grown crystals is preferably 2 or more and 80 or less. The number of grown crystals is limited by the above-described die pack length L and thickness t. However, considering the mass productivity, it is preferable because the temperature balance adjustment in the number direction becomes difficult when the number exceeds 80. Absent.
　以下、本発明に係るダイパックを使用して、ＥＦＧ法においてサファイア単結晶を育成する方法について、図４～図６を参照しながら詳細に説明する。 Hereinafter, a method for growing a sapphire single crystal in the EFG method using the die pack according to the present invention will be described in detail with reference to FIGS.
　図４に示すように、サファイア単結晶の製造装置３は、サファイア単結晶を育成する育成容器４と、育成したサファイア単結晶を引き上げる引き上げ容器５とから構成され、ＥＦＧ法により複数枚のサファイア単結晶２０（以下、単にサファイア単結晶２０と記載する）を成長させる。 As shown in FIG. 4, the sapphire single crystal manufacturing apparatus 3 includes a growth container 4 for growing a sapphire single crystal and a pulling container 5 for pulling up the grown sapphire single crystal, and a plurality of sapphire single crystals by the EFG method. Crystal 20 (hereinafter simply referred to as sapphire single crystal 20) is grown.
　育成容器４は、坩堝６、坩堝駆動部７、ヒータ８、電極９、ダイパック１０２、および断熱材１０を備える。坩堝６はモリブデン又はモリブデンの合金製であり、酸化アルミニウム原料を溶融する。坩堝駆動部７は、坩堝６をその鉛直方向を軸として回転させる。ヒータ８は坩堝６を加熱する。また、電極９はヒータ８を通電する。 The growth container 4 includes a crucible 6, a crucible driving unit 7, a heater 8, an electrode 9, a die pack 102, and a heat insulating material 10. The crucible 6 is made of molybdenum or an alloy of molybdenum and melts the aluminum oxide raw material. The crucible drive unit 7 rotates the crucible 6 with the vertical direction as an axis. The heater 8 heats the crucible 6. The electrode 9 energizes the heater 8.
　ダイパック１０２は坩堝６内に設置され、サファイア単結晶を引き上げる際の酸化アルミニウム融液（以下、必要に応じて単に「融液」と表記）の液面形状を決定する。また断熱材１０は、坩堝６とヒータ８とダイパック１０２を取り囲んでいる。 The die pack 102 is installed in the crucible 6 and determines the liquid surface shape of the aluminum oxide melt (hereinafter simply referred to as “melt” as necessary) when pulling up the sapphire single crystal. The heat insulating material 10 surrounds the crucible 6, the heater 8, and the die pack 102.
　更に育成容器４は、雰囲気ガス導入口１１と排気口１２を備える。雰囲気ガス導入口１１は、雰囲気ガスとして例えばアルゴンガスを育成容器４内に導入するための導入口であり、坩堝６やヒータ８、およびダイパック１０２の酸化消耗を防止する。一方、排気口１２は育成容器４内を排気するために備えられる。 Furthermore, the growth container 4 includes an atmospheric gas inlet 11 and an exhaust 12. The atmosphere gas introduction port 11 is an introduction port for introducing, for example, argon gas into the growth vessel 4 as the atmosphere gas, and prevents oxidation of the crucible 6, the heater 8, and the die pack 102. On the other hand, the exhaust port 12 is provided for exhausting the inside of the growth vessel 4.
　引き上げ容器５は、シャフト１３、シャフト駆動部１４、ゲートバルブ１５、および基板出入口１６を備え、種結晶２１から結晶成長した複数枚のサファイア単結晶２０を引き上げる。シャフト１３は種結晶２１を保持する。またシャフト駆動部１４は、シャフト１３を坩堝６に向けて昇降させると共に、その昇降方向を軸としてシャフト１３を回転させる。ゲートバルブ１５は育成容器４と引き上げ容器５とを仕切る。また基板出入口１６は、種結晶２１を出し入れする。 The pulling container 5 includes a shaft 13, a shaft driving unit 14, a gate valve 15, and a substrate inlet / outlet 16, and pulls up a plurality of sapphire single crystals 20 grown from the seed crystal 21. The shaft 13 holds the seed crystal 21. Further, the shaft driving unit 14 moves the shaft 13 up and down toward the crucible 6 and rotates the shaft 13 around the lifting direction. The gate valve 15 partitions the growth container 4 and the pulling container 5. The substrate entrance / exit 16 takes in and out the seed crystal 21.
　なお製造装置３は、図示されない制御部も有し、この制御部により坩堝駆動部７およびシャフト駆動部１４の回転を制御する。 The manufacturing apparatus 3 also has a control unit (not shown), and the rotation of the crucible drive unit 7 and the shaft drive unit 14 is controlled by this control unit.
　次に、前記製造装置３を使用したサファイア単結晶２０の製造方法について、図４～図６を参照しながら説明する。最初にサファイア単結晶の原料である造粒された酸化アルミニウム原料粉末（99．99％酸化アルミニウム）をダイパック１０２が収納された坩堝６に所定量投入して充填する。酸化アルミニウム原料粉末には、製造しようとするサファイア単結晶の純度又は組成に応じて、酸化アルミニウム以外の化合物や元素が含まれていても良い。 Next, a method for manufacturing the sapphire single crystal 20 using the manufacturing apparatus 3 will be described with reference to FIGS. First, a predetermined amount of agglomerated aluminum oxide raw material powder (99.99% aluminum oxide), which is a raw material of sapphire single crystal, is charged into a crucible 6 in which a die pack 102 is housed. The aluminum oxide raw material powder may contain compounds and elements other than aluminum oxide depending on the purity or composition of the sapphire single crystal to be produced.
　続いて、坩堝６やヒータ８若しくはダイパック１０２を酸化消耗させないために、育成容器４内をアルゴンガスで置換し、酸素濃度を所定値以下とする。 Subsequently, in order not to oxidize the crucible 6, the heater 8, or the die pack 102, the inside of the growth vessel 4 is replaced with argon gas, and the oxygen concentration is set to a predetermined value or less.
　次に、ヒータ８で加熱して坩堝６を所定の温度とし、酸化アルミニウム原料粉末を溶融する。酸化アルミニウムの融点は2050℃～2072℃程度なので、坩堝６の加熱温度はその融点以上の温度（例えば2100℃）に設定する。加熱後しばらくすると原料粉末が溶融して、酸化アルミニウム融液１７が用意される。図５(ａ)に示すように、融液の一部はダイのスリット２０２を毛細管現象により上昇してダイパック１０２の表面に達し、スリット上部に融液溜まり１８が形成される。 Next, the crucible 6 is heated to a predetermined temperature by the heater 8 to melt the aluminum oxide raw material powder. Since the melting point of aluminum oxide is about 2050 ° C. to 2072 ° C., the heating temperature of the crucible 6 is set to a temperature higher than the melting point (for example, 2100 ° C.). After a while after heating, the raw material powder melts and an aluminum oxide melt 17 is prepared. As shown in FIG. 5A, a part of the melt ascends through the slit 202 of the die due to capillary action and reaches the surface of the die pack 102, and the melt pool 18 is formed above the slit.
　次に、図５(ｂ)に示すように、スリット上部の融液溜まり１８の長手方向に対して垂直な角度に種結晶２１を保持しつつ、種結晶２１の下端が全てのダイの融液溜まり１８の融液面に接触するまで降下させる。なお、種結晶２１は、予め基板出入口１６から引き上げ容器５内に導入しておく。 Next, as shown in FIG. 5 (b), while holding the seed crystal 21 at an angle perpendicular to the longitudinal direction of the melt reservoir 18 above the slit, the lower end of the seed crystal 21 is the melt of all the dies. Lower until it contacts the melt surface of the reservoir 18. The seed crystal 21 is previously introduced into the pulling container 5 from the substrate entrance 16.
　図５(ａ),(ｂ)に示す種結晶２１の形状は一例である。種結晶２１の平面方向とダイパック１０２の長手方向が、互いに９０°の角度で直交となるように配置されることによって、一枚の種結晶から複数枚のサファイア単結晶を同時に育成することが可能となる。従って、育成されたサファイア単結晶２０の平面方向も、種結晶２１の平面方向に９０°の角度で以て直交することになる。 The shape of the seed crystal 21 shown in FIGS. 5A and 5B is an example. By arranging the plane direction of the seed crystal 21 and the longitudinal direction of the die pack 102 so as to be orthogonal to each other at an angle of 90 °, it is possible to simultaneously grow a plurality of sapphire single crystals from one seed crystal. It becomes. Therefore, the plane direction of the grown sapphire single crystal 20 is also orthogonal to the plane direction of the seed crystal 21 at an angle of 90 °.
　次に、図５(ｃ)に示すようにネック部分２２を形成する。具体的には、まずシャフト１３により基板保持具を高速で上昇させながら細いネック部分２２を作製（ネッキング）する。以降ではこの工程をネッキング工程と称する。 Next, the neck portion 22 is formed as shown in FIG. Specifically, first, a thin neck portion 22 is produced (necked) while the substrate holder is raised at high speed by the shaft 13. Hereinafter, this process is referred to as a necking process.
　ネッキング工程を経た後、ヒータ８を制御して坩堝６の温度を降下させると共に、基板保持具の上昇速度を所定の速度に設定し、種結晶２１を中心に、サファイア単結晶２０をダイパックの幅方向に拡幅するように結晶成長させる（スプレーディング工程）。 After passing through the necking step, the heater 8 is controlled to lower the temperature of the crucible 6, and the ascent rate of the substrate holder is set to a predetermined rate, and the sapphire single crystal 20 is centered on the seed crystal 21 and the width of the die pack. Crystal growth is performed so as to widen in the direction (spraying process).
　サファイア単結晶２０が、ダイの全幅まで拡幅すると（フルスプレッド）、ダイパックの幅Ｗで規定される結晶幅を有する直胴部分２３の育成が開始される（直胴工程）。直胴工程では、互いに略平行で対向する側面で規定される直胴部分を有する複数のサファイア単結晶２０が製造される。直胴長さは特に限定されないが、２インチ以上（50.8ｍｍ以上）が好ましい。 When the sapphire single crystal 20 is expanded to the full width of the die (full spread), the growth of the straight body portion 23 having a crystal width defined by the width W of the die pack is started (straight body process). In the straight body process, a plurality of sapphire single crystals 20 having a straight body portion defined by side surfaces that are substantially parallel to and opposed to each other are manufactured. Although the length of the straight body is not particularly limited, it is preferably 2 inches or more (50.8 mm or more).
　前述のネッキング工程、スプレーディング工程および直胴工程を経て、図６に示すようなサファイア単結晶２０が得られる。 The sapphire single crystal 20 as shown in FIG. 6 is obtained through the above-described necking process, spraying process, and straight body process.
　この後、得られたサファイア単結晶２０を放冷し、ゲートバルブ１５を空け、引き上げ容器５側に移動して、基板出入口１６から取り出す。 Thereafter, the obtained sapphire single crystal 20 is allowed to cool, the gate valve 15 is opened, the sapphire single crystal 20 is moved to the pulling container 5 side, and taken out from the substrate entrance 16.
　尚、種結晶２１の結晶面を任意に設定することで、サファイア単結晶２０の主面の結晶面も任意に変更することが可能となる。サファイア単結晶２０の主面は、ａ面に限定されず、例えばｃ面、ｒ面、ｍ面等、所望の結晶面に設定することが可能である。 It should be noted that the crystal plane of the main surface of the sapphire single crystal 20 can be arbitrarily changed by arbitrarily setting the crystal plane of the seed crystal 21. The main surface of the sapphire single crystal 20 is not limited to the a-plane, and can be set to a desired crystal plane such as a c-plane, r-plane, or m-plane.
　図６に示すように、本発明のダイパックを用いて育成されたサファイア単結晶２０は、種結晶と少なくとも直胴部分を有し、前記直胴部分の下端が前記各ダイの段差Ｈに応じた段差形状を有している。さらに、ダイパックの温度勾配が良好な状態で結晶育成が行われるため、直胴部分に結晶外形の細りが発生せず、育成結晶幅および厚みが均一なサファイア単結晶が得られる。 As shown in FIG. 6, the sapphire single crystal 20 grown using the die pack of the present invention has a seed crystal and at least a straight body portion, and the lower end of the straight body portion corresponds to the step H of each die. It has a step shape. Further, since crystal growth is performed in a state where the temperature gradient of the die pack is good, a thin sapphire single crystal having a uniform growth crystal width and thickness is obtained without thinning of the crystal shape in the straight body portion.
　また同様の理由で、直胴部分に線欠陥（slip）や結晶粒界（grain boundary）等の結晶欠陥のない結晶品質に優れたサファイア単結晶が得られる。「直胴部分に結晶欠陥を有さない」とは、育成結晶の直胴部分のうち、基板加工に使用される領域に上記のような結晶欠陥が存在しないことを意味する。具体的には、育成結晶の幅に対し95%以内の領域に結晶欠陥がないことを意味する。 For the same reason, a sapphire single crystal excellent in crystal quality free from crystal defects such as line defects (slip) and crystal grain boundaries (grain boundaries) in the straight body portion can be obtained. “The straight body portion has no crystal defects” means that the crystal defects as described above do not exist in the region used for substrate processing in the straight body portion of the grown crystal. Specifically, it means that there is no crystal defect in a region within 95% of the width of the grown crystal.
　以上説明したような製造装置３、およびダイパック１０２を用いることにより、共通の種結晶２１から結晶品質にばらつきのないサファイア単結晶２０を製造することが出来るため、サファイア単結晶の量産性を向上させることが可能となる。このようにして得られたサファイア単結晶に研磨加工を施し、サファイア基板を提供することができるため、サファイア基板の量産性をも向上させることが可能となる。 By using the manufacturing apparatus 3 and the die pack 102 as described above, the sapphire single crystal 20 having no variation in crystal quality can be manufactured from the common seed crystal 21, so that the mass productivity of the sapphire single crystal is improved. It becomes possible. Since the sapphire single crystal thus obtained can be polished to provide a sapphire substrate, the mass productivity of the sapphire substrate can be improved.
　図１に一例として示すダイパック１０２および図４に示すサファイア単結晶製造装置を用いて、上述した方法でｃ面を主面とする複数のサファイア単結晶２０を製造した。 Using a die pack 102 shown as an example in FIG. 1 and a sapphire single crystal manufacturing apparatus shown in FIG. 4, a plurality of sapphire single crystals 20 having a c-plane as a main surface were manufactured by the method described above.
　表１に実施例１～４で使用したダイパックの長さＬ、幅Ｗ、および坩堝の直径φの条件を示す。また、実施例１～４のダイパックを用いてサファイア単結晶を育成した結果、結晶欠陥や結晶外形の細りが発生せず、最も良好な育成が行われたダイパックの段差Ｈを◆印でプロットし、図７～１０に示す。 Table 1 shows the conditions of the length L and width W of the die pack used in Examples 1 to 4 and the diameter φ of the crucible. In addition, as a result of growing the sapphire single crystal using the die packs of Examples 1 to 4, the step H of the die pack in which the best growth was performed without causing crystal defects and thinning of the crystal outline was plotted with ◆ marks. 7 to 10 are shown.
比較例Comparative example
　表２の比較例１～４には、実施例１～４と同じＬ、Ｗ、φの条件を用いて、すでに説明した方法により求められた係数ａ、ｃ、ｄを示す。また、係数ｂを調整し得られた曲線を図７～１０に示す。 Comparative Examples 1 to 4 in Table 2 show coefficients a, c, and d obtained by the method described above using the same L, W, and φ conditions as in Examples 1 to 4. Curves obtained by adjusting the coefficient b are shown in FIGS.
　図７～１０に示すように、最も良好な育成が行われたダイパックの段差Ｈの変化は、ｘの２次以上４次以下の関数として規定されることがわかった。さらに、計算によって求めた比較例１～４の曲線は、実際の段差形状を示す実施例１～４の結果とよく合うという結果が得られた。従って、計算によって段差形状を決定する本発明の手法は有効であるという結果が示された。 As shown in FIGS. 7 to 10, it was found that the change in the level difference H of the die pack that was most successfully grown was defined as a function of the second order to the fourth order of x. Further, it was obtained that the curves of Comparative Examples 1 to 4 obtained by calculation matched well with the results of Examples 1 to 4 showing the actual step shape. Therefore, it was shown that the method of the present invention for determining the step shape by calculation is effective.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
１０１　ダイ
１０２　ダイパック
２０１　仕切り板
２０２　スリット
３　サファイア単結晶の製造装置
４　育成容器
５　引き上げ容器
６　坩堝
７　坩堝駆動部
８　ヒータ
９　電極
１０　断熱材
１１　雰囲気ガス導入口
１２　排気口
１３　シャフト
１４　シャフト駆動部
１５　ゲートバルブ
１６　基板出入口
１７　酸化アルミニウム融液
１８　酸化アルミニウム融液溜まり
２０　複数枚のサファイア単結晶
２１　種結晶
２２　ネック部分
２３　直胴部分
Ｌ　ダイパックの長さ
Ｗ　ダイパックの幅
φ　坩堝の直径 DESCRIPTION OF SYMBOLS 101 Die 102 Die pack 201 Partition plate 202 Slit 3 Sapphire single crystal manufacturing apparatus 4 Growth vessel 5 Pulling vessel 6 Crucible 7 Crucible drive unit 8 Heater 9 Electrode 10 Heat insulating material 11 Atmospheric gas inlet 12 Exhaust port 13 Shaft 14 Shaft drive unit 15 Gate valve 16 Substrate inlet / outlet 17 Aluminum oxide melt 18 Aluminum oxide melt pool 20 Multiple sapphire single crystals 21 Seed crystal 22 Neck portion 23 Straight barrel portion L Die pack length W Die pack width φ Diameter of crucible

Claims (5)

  1. ＥＦＧ法によるサファイア単結晶の育成に使用するダイパックであって、
    前記ダイパックの中心からの距離ｘにおいて
    前記ダイパック中で最も低いダイ高さに対する段差Ｈを有し、
    前記段差Ｈが、前記ｘの2次以上４次以下の関数で規定されることを特徴とするダイパック。     A die pack used for growing a sapphire single crystal by the EFG method,
    A step H with respect to the lowest die height in the die pack at a distance x from the center of the die pack;
    The die pack characterized in that the step H is defined by a function of the second order to the fourth order of x.
  2. 前記関数が、前記ｘの2次以上４次以下であり、かつ
    前記ダイパックの中心における前記段差Ｈをｃ、
    前記ダイパックの最も外側における前記段差Ｈをｄとし、
    前記ダイパックの幅、長さ、坩堝の直径をそれぞれＷ、Ｌ、φとしたとき、
    前記ｃは、ｃ＝Ｌ／Ｗ／４
    前記ｄは、
    Figure JPOXMLDOC01-appb-M000001
     を満たすことを特徴とする請求項１に記載のダイパック。     The function is not less than the second order and the fourth order of the x, and the step H at the center of the die pack is c,
    The step H on the outermost side of the die pack is d,
    When the width, length, and crucible diameter of the die pack are W, L, and φ,
    The c is c = L / W / 4.
    Said d is
    Figure JPOXMLDOC01-appb-M000001
     The die pack according to claim 1, wherein:
  3. 前記関数が、Ｈ=ａｘ3＋ｂｘ2＋ｃであり、
    前記ａは、ａ＝Ｌ／Ｗ／１００、
    前記ｃは、ｃ＝Ｌ／Ｗ／４
    を満たし、かつ、
    前記ｂが、前記ｄを満たすように最小二乗法により求められた係数
    であることを特徴とする請求項２に記載のダイパック。     The function is H = ax 3 + bx 2 + c,
    A is a = L / W / 100,
    The c is c = L / W / 4.
    And satisfy
    The die pack according to claim 2, wherein the b is a coefficient obtained by a least square method so as to satisfy the d.
  4. ＥＦＧ法におけるサファイア単結晶の育成装置であって、請求項１～３のいずれかに記載のダイパックを用いることを特徴とするサファイア単結晶育成装置。 An apparatus for growing a sapphire single crystal in an EFG method, wherein the die pack according to any one of claims 1 to 3 is used.
  5. ＥＦＧ法におけるサファイア単結晶の育成方法であって、請求項１～３のいずれかに記載のダイパックを使用することを特徴とするサファイア単結晶の育成方法。 A method for growing a sapphire single crystal in an EFG method, wherein the die pack according to any one of claims 1 to 3 is used.
PCT/JP2017/001702 2016-01-22 2017-01-19 Die pack, sapphire single-crystal growing device, and sapphire single-crystal growing method WO2017126594A1 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4465481B2 (en) * 2000-05-10 2010-05-19 並木精密宝石株式会社 Single crystal material manufacturing method, seed substrate, die, and single crystal material manufacturing apparatus
US20140272413A1 (en) * 2013-03-15 2014-09-18 Saint-Gobain Ceramics & Plastics, Inc. Sapphire Ribbons and Apparatus and Method for Producing a Plurality of Sapphire Ribbons Having Improved Dimensional Stability

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4465481B2 (en) * 2000-05-10 2010-05-19 並木精密宝石株式会社 Single crystal material manufacturing method, seed substrate, die, and single crystal material manufacturing apparatus
US20140272413A1 (en) * 2013-03-15 2014-09-18 Saint-Gobain Ceramics & Plastics, Inc. Sapphire Ribbons and Apparatus and Method for Producing a Plurality of Sapphire Ribbons Having Improved Dimensional Stability

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