JP6364647B2 - Large sapphire multi-substrate - Google Patents

Description

  The present invention relates to a sapphire multi-substrate in which a plurality of sapphire ribbons are grown from a common seed crystal by an EFG (Edge-defined Film-fed. Growth Method) method.

  Currently, a sapphire single crystal substrate is widely used as a semiconductor substrate material typified by light emitting elements such as LEDs. As a mass production method of a sapphire single crystal substrate, a sapphire single crystal serving as a substrate material is grown in a lump by the CZ method, sliced from a sapphire ingot obtained by the growth, and grown in a plate shape by an EFG method, The method is roughly divided into a method of cutting out the sapphire ribbon obtained by the growth into an arbitrary shape. Among these two growing methods, as a mass production method of a sapphire ribbon using the EFG method, a growing method described in Japanese Patent No. 44655481 (hereinafter described as Patent Document 1) is disclosed. Further, for a single sapphire ribbon, a large sapphire ribbon having a width of 150 mm or more and a method for growing the sapphire ribbon are disclosed as JP 2010-229030 (hereinafter referred to as Patent Document 2).

  The above-mentioned Patent Document 1 has the technical feature of growing a sapphire multi-substrate using a single seed crystal, and can improve the mass productivity of the sapphire ribbon. Further, Patent Document 2 has a technical feature of growing a large sapphire ribbon as an optical application, and enables process control and equipment improvement corresponding to the growth of a large sapphire ribbon.

Japanese Patent No. 4465481 JP2010-229030

  While having the above-described technical features and the effects thereof, the method described in Patent Document 2 has a problem that due to its structure, a plurality of sapphire ribbons cannot be grown simultaneously. Moreover, in the growth method described in Patent Document 1, since the radiant heat for each sapphire ribbon in the sapphire multi-substrate and the temperature in the growth furnace affect each other, for each sapphire ribbon pulled up from a common die, A line defect, a crystal grain boundary, etc. generate | occur | produce and it is difficult to make compatible maintenance of the crystal quality which can be used as a semiconductor substrate material, and enlargement of a sapphire ribbon.

  In order to solve the above problems, the invention described in the present application is a method for simultaneously pulling up a sapphire ribbon, and an object thereof is to provide a sapphire multi-substrate capable of increasing the size of the sapphire ribbon while maintaining the crystal quality.

  For the above purpose, in the first aspect of the present invention, in the growth of a sapphire multi-substrate of 150 mm or more, the gap between each sapphire ribbon is set to a range of 1 mm or more and less than the thickness dimension of the sapphire ribbon. This is its technical feature. More specifically, the growth conditions of the large substrate in the growth furnace are stabilized by the growth shape of the sapphire multi-substrate.

  In the second aspect of the present invention, the technical feature is that the lower limit of the gap in the invention described in the first aspect is 2 mm.

Further, according to the third aspect of the present invention, in the invention described in the second aspect, the axial displacement of the crystal orientation plane with respect to the surface direction of the sapphire ribbon is within 0.5 °. It is a feature.

  The growth shape described above enables the sapphire multi-substrate described in the present invention to grow a plurality of large substrates using a sapphire multi-substrate when growing a large substrate having a width of 150 mm or more. More specifically, by setting the gap to a range of 1 mm or more and less than the thickness dimension of the sapphire ribbon, the temperature balance in the sapphire multi-substrate is adjusted to the temperature in the furnace and the radiant heat between the sapphire ribbons. Therefore, it is possible to maintain the crystal quality of each sapphire ribbon and to simultaneously grow a plurality of large substrates at the same pulling speed while maintaining conditions suitable for crystal growth.

  In addition, in the present invention, the setting of the gap also gives the effect of suppressing axial deviation due to an increase in the thickness of the seed crystal and preventing sapphire melt from entering the gap during normal crystal growth. . This is accompanied by simultaneous growth of a large substrate on a sapphire multi-substrate. That is, in the crystal growth of a large substrate using a sapphire multi-substrate, the seed crystal is deformed as the crystal grows due to its structure, and an axial shift occurs in the crystal orientation plane. Moreover, when the deformation is suppressed by increasing the thickness of the seed crystal, the melt enters the gaps between the sapphire ribbons due to the surface tension of the sapphire melt. In the present invention, these problems are also solved by setting the gap, and it is possible to provide a sapphire multi-substrate specialized for a large substrate.

  Further, by using the second aspect of the present invention, it is possible to grow a plurality of large substrates using a sapphire multi-substrate under more suitable conditions for increasing the thickness of the seed crystal. This is the effect of setting the gap described in the first aspect as the minimum condition and making the gap setting described in the present aspect more practical. That is, the thickness of the seed crystal actually used is 2 mm or more with respect to the effects of maintaining the temperature conditions, suppressing the axial deviation, and preventing the melt from entering. If the gap is set to about 1 mm with respect to the seed crystal, the melt enters the gap when the material melt is melted too much due to a mistake in setting growth conditions or the like. On the other hand, by setting the lower limit of the gap to 2 mm, the melt can be prevented from entering, and the crystal quality suitable for semiconductor applications can be maintained while maintaining a stable and uniform temperature balance.

  Moreover, by using the third aspect of the present invention, the density of the sapphire ribbon in the sapphire multi-substrate can be increased, and the processing as a semiconductor crystal can be facilitated. This is because the growth method described in the present application is the EFG method, and the crystal orientation to be grown can be controlled, and the effect of reflecting the misalignment of the crystal axis in the workability. That is, when a sapphire ribbon is polished as a semiconductor crystal, correction in the axial direction of 0.5 ° requires 1.35 mm per 150 mm. On the other hand, the sapphire ribbon described in the second aspect requires a thickness of 2 mm or more from the required gap. For this reason, by keeping the misalignment of the crystal axis within the range, a sapphire ribbon that takes into consideration the workability as a crystal for semiconductors in addition to the effects on growth and crystal quality imparted by the second aspect is obtained. be able to.

As described above, by using the structure described in the claims of the present application, it is possible to provide a sapphire multi-substrate capable of increasing the size of the sapphire ribbon while maintaining the crystal quality.

Overall perspective view of a sapphire multi-substrate used in the best mode of the present invention Enlarged view of the seed substrate of the sapphire multi-substrate shown in FIG. Schematic diagram showing before and after the seed crystal pulling in the best embodiment of the present invention Top view of the sapphire multi-substrate shown in FIG.

  Hereinafter, the best embodiment of the present invention will be described with reference to FIGS. 1, 2, 3 and 4. In addition, about the symbol and component number in a figure, the common symbol or number is provided to what functions as the same component.

  FIG. 1 is an overall perspective view of a sapphire multi-substrate used in this embodiment, FIG. 2 is an enlarged view of a seed substrate of FIG. 1, and FIG. FIG. 4 shows a schematic view and FIG. 4 shows a top view of the sapphire multi-substrate in FIG. In addition, about the mechanism of the seed crystal upper part and die | dye lower part, description in a figure is abbreviate | omitted.

  1, 2, 3, and 4, the sapphire multi-substrate described in this embodiment is used for growing a seed crystal 2 made of single-crystal sapphire having a crystal orientation plane S 1 for growth as a c-plane. A configuration arranged perpendicular to the die 4 is used. Therefore, it becomes possible to grow the sapphire multi-substrate 1 having a plurality of sapphire ribbons 3 from a single die. Here, in the EFG method which is the growing method of the present embodiment, the sapphire multi-substrate 1 grows in a crystal orientation along the crystal orientation S1 of the seed crystal 2. For this reason, all the sapphire ribbons 2 in the sapphire multi-substrate 1 in the present embodiment are single crystal substrates with the substrate plane being c-plane. From the same technical point of view, the substrate plane of the sapphire ribbon 3 can be changed by setting the crystal orientation plane S1 of the seed crystal to an arbitrary crystal plane such as an r plane.

  In addition to the effects of the basic configuration described above, in this embodiment, the width of the crystal grown by the die 4 is 150 mm, the thickness is 3 mm, the gap g between the dies is 2 mm, and the thickness of the seed crystal 2 is 2 mm. For this reason, regarding the crystal quality in the sapphire multi-substrate, the temperature balance in the sapphire multi-substrate is kept uniform by the temperature in the furnace and the radiant heat between the sapphire ribbons, Crystal quality can be maintained and multiple large substrates can be grown simultaneously. More specifically, in the crystal arrangement that occurs between the sapphire melt at the end of the die and the crystal end face on the seed crystal side that grows, the temperature of each sapphire ribbon end face is determined as the melt on the die. It was kept uniform by the radiant heat between the sapphire ribbons, and the temperature balance between the growing sapphire ribbons could be maintained in a state suitable for crystal growth. In addition, in this embodiment, the growth conditions of the sapphire ribbons 3 are uniform by maintaining the temperature balance. For this reason, it has become possible to pull up a large semiconductor substrate having no line defects and crystal grain boundaries at a common speed.

  In this embodiment, a plate-shaped seed crystal having a thickness t of 2 mm is used for growing a sapphire multi-substrate having a sapphire ribbon having a thickness of 3 mm and a width of 150 mm. Therefore, it is possible to prevent the seed crystal from being deformed when the crystal is pulled, and to suppress the axial deviation between the crystal orientation plane S2 of the grown sapphire ribbon and the crystal orientation plane S1 of the seed crystal. This is an effect associated with crystal growth using a sapphire multi-substrate, and the seed crystal 2 that becomes a seed crystal for crystal growth is not only a sapphire ribbon that maintains strength and grows even under high temperature conditions in a growth furnace. The above effect is obtained by adopting a structure that is not deformed by its own weight. In addition, according to the thickness of the seed crystal 2, in this embodiment, the gap between the sapphire ribbons is set to 2 mm by the gap g between the dies. For this reason, at the time of contact between the seed crystal 2 and the tip of the die, it is possible to grow the crystal with high mass productivity by preventing the sapphire melts 5 of adjacent dies from being connected by the surface tension of each other.

  In addition to the above effects, in this embodiment, the axial deviation of the crystal orientation plane in each sapphire ribbon is kept within 0.5 ° due to the shape of the seed crystal and its rigidity. More specifically, the deformation of the seed crystal is suppressed against the load of the sapphire ribbon that increases during crystal growth, and the crystal orientation plane between the crystal orientation plane S1 of the seed crystal and the crystal orientation plane S2 of the sapphire ribbon 3 The seed crystal shape is such that the axial misalignment generated in the step falls within the numerical value. As a result, the polishing amount in the thickness direction necessary for correcting the axial deviation for each sapphire ribbon 3 can be kept within about 1.5 mm. For this reason, the sapphire multi-substrate described in the present embodiment can provide the effect of improving the workability as a crystal for semiconductors in addition to the above-described effects on growth and crystal quality.

As described above, by using the substrate described in this embodiment, a sapphire multi-substrate capable of increasing the size of the sapphire ribbon while maintaining the crystal quality can be provided.

DESCRIPTION OF SYMBOLS 1 Sapphire multi-substrate 2 Seed crystal 3 Sapphire ribbon 4 Die 5 Sapphire melt S1, S2 Crystal orientation surface g Gap between dies t Thickness of seed crystal

Claims (1)

A sapphire multi-substrate in which a plurality of sapphire ribbons are grown from a common seed crystal by an EFG method,
The seed crystal has a thickness of 2 mm or more,
The gap between each sapphire ribbon is set to a range of 2 mm or more and less than the thickness dimension of the sapphire ribbon , the width is 150 mm or more , and the axial deviation between the crystal orientation plane of the seed crystal and the crystal orientation plane of the sapphire ribbon is 0. Sapphire multi-substrate that is within 5 ° .

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