JP2016175813A - Single crystal growth apparatus with laser beam division device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a single crystal growth apparatus that is for floating molten zone type single crystal manufacture in which a single crystal is raised from a raw material rod, and can reduce laser power source costs.SOLUTION: The present invention relates to a single crystal growth device 100 which raises a single crystal from a raw material rod 1, the single crystal growth device 100 comprising: a semiconductor laser device 20 which has a laser power source 10 and emits semiconductor laser light 5 based upon electric power supplied by the laser power source 10; a laser light division device 30 which divides the semiconductor laser light 5 into M heating laser light beams 3; and laser irradiation heads 50-55 which emit the M heating laser light beams 3 toward the raw material rod 1. In the single crystal growth device 100, the laser light division device 30 comprises: a collimator lens which converts the semiconductor laser light into parallel light; a plurality of division mirrors which divide the semiconductor laser light into M semiconductor laser light beams; a plurality of attenuation mirrors which equalize laser light intensity among the M semiconductor laser light beams; and a condenser lens which condenses the M semiconductor laser light beams on optical fibers 41-45.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a single crystal growing apparatus having a laser beam splitting apparatus.

Conventionally, in a floating-melt-zone type single crystal manufacturing apparatus using a heating laser beam, a method of directly irradiating and heating a raw material rod with a plurality of heating laser beams from the surroundings is known (for example, Patent Document 1).
[Prior art documents]
[Non-patent literature]
[Non-Patent Document 1] Matsuda, et al. , “Magnetic dispersion and anisotropy in multiferroic BiFeO ₃ ” Phys. Rev. Lett. The American Physical Society, August 8, 2012, Vol. 109,067205.
[Patent Literature]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2011-144081

  FIG. 26 shows an example of the configuration of a conventional single crystal growth apparatus 500. The single crystal growth apparatus 500 includes a plurality of laser power sources 510a, 510b, 510c, 510d, and 510e, a plurality of semiconductor lasers 520a, 520b, 520c, 520d, and 520e, and a plurality of light beams for heating the raw material rod 501. Fibers 540a, 540b, 540c, 540d, and 540e and a plurality of laser irradiation heads 550a, 550b, 550c, 550d, and 550e are provided. FIG. 26 shows a case where there are five semiconductor laser sources and five constant current sources to the semiconductor laser light source. The semiconductor laser 520 used for the floating melting zone method is an expensive device with a cost of several million yen. The laser power supply is also in the price range of several hundred thousand yen, and if it is five units, it will be as high as several million yen. Five laser power sources 510a, 510b, 510c, 510d, and 510e are connected to five semiconductor lasers 520a, 520b, 520c, 520d, and 520e, respectively, and the five laser power sources 510a, 510b, 510c, 510d, and 510e are simultaneously connected. A computer control system to control is essential. The development of the control software is expensive. Further, the semiconductor laser 520 needs to have a temperature control accuracy within ± 0.5 ° C., and when branching such cooling water with high temperature accuracy from one cooling device, it is necessary to finely adjust the amount of branched water. . The environmental gas used for the semiconductor laser 520 requires dry air with low humidity. The semiconductor laser device is cooled by cooling water. Therefore, it is easy for condensation to form around the semiconductor laser 520, and it is necessary to introduce a dry gas into each semiconductor laser 520. As described above, the plurality of semiconductor lasers 520 and the laser power source 510 not only greatly increase the cost of the single crystal growth apparatus 500 but also increase the load on incidental facilities.

  According to a first aspect of the present invention, in a single crystal growth apparatus for growing a single crystal from a raw material rod, a semiconductor laser apparatus that has a laser power source and emits semiconductor laser light based on power supplied by the laser power source, Provided is a single crystal growth apparatus that includes a laser beam splitting device that splits a semiconductor laser beam into M heating laser beams and a laser irradiation head that irradiates M heating laser beams toward a raw material rod.

An example of the perspective view of the single crystal growth apparatus 100 is shown. An example of the top view of the vicinity of the raw material stick | rod 1 is shown. An example of the configuration of the semiconductor laser device 20 is shown. The schematic diagram of the optical fiber 40 is shown. An example of the configuration of the semiconductor laser device 20 is shown. An example of a top view of the semiconductor laser device 20 is shown. An example of a front view of the semiconductor laser device 20 is shown. An example of the side view of the semiconductor laser element 201 and a collimator lens is shown. An example of the top view of the semiconductor laser element 201 and a collimator lens is shown. An example of a method for dividing the semiconductor laser beam 5 will be described. An example of a method for attenuating the semiconductor laser beam 5 and a fiber condensing lens will be described. The simulation experiment result of the semiconductor laser beam 5 divided into M is shown. A method for dividing the semiconductor laser beam 5 according to the second embodiment will be described. An example of the structure of the 1st condensing lens 36 and the 2nd condensing lens 37 is shown. An example of the structure of the laser beam splitting apparatus 30 which concerns on Example 3 is shown. An example of the structure of the laser beam splitting apparatus 30 which concerns on Example 4 is shown. An example of the structure of the laser beam splitting apparatus 30 which concerns on Example 5 is shown. An example of the structure of the laser beam splitting apparatus 30 which concerns on Example 6 is shown. An example of an incident method to the laser beam splitting apparatus 30 according to the first splitting method will be shown. An example of the structure of the laser beam splitting apparatus 30 which concerns on a 2nd splitting system is shown. An example of an incident method to the laser beam splitting device 30 according to the second splitting method will be shown. An example of the division | segmentation fiber 80 which concerns on a 3rd division system is shown. An example of the division | segmentation fiber 80 which concerns on a 3rd division system is shown. An example of the configuration of the laser irradiation head 50 is shown. A top view of single crystal growth device 500 concerning comparative example 1 is shown. An example of the top view of the single crystal growth apparatus 100 is shown. 1 shows a configuration of a single crystal growth apparatus 500 in which a laser head unit is fixed to the upper part of the apparatus. An example of the structure of the conventional single crystal growth apparatus 500 is shown.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

[Example 1]
FIG. 1 shows an example of a perspective view of a single crystal growing apparatus 100. FIG. 2 shows an example of a top view in the vicinity of the raw material rod 1. The single crystal growing apparatus 100 includes a laser power source 10, a semiconductor laser apparatus 20, a laser beam splitting apparatus 30, M optical fibers, M laser irradiation heads, and M dampers. In this example, the number of divisions M = 5 is shown.

  The single crystal growing apparatus 100 grows a single crystal on the seed crystal rod 2 by a floating melting zone method. In the floating melting zone method, a heating source for heating the raw material rod 1 and the seed crystal rod 2 to a high temperature is required. The single crystal growing apparatus 100 of this example uses a heating laser beam 3 as a heating source for the columnar raw material rod 1 and seed crystal rod 2. The heating laser beam 3 is incident on the raw material rod 1 and the seed crystal rod 2 radially with the central axes of the raw material rod 1 and the seed crystal rod 2 as the center. The heating laser beam 3 is a laser beam having a substantially rectangular irradiation shape and a uniform two-dimensional surface intensity of the substantially rectangular irradiation shape.

  The semiconductor laser device 20 is driven by the power source from the laser power source 10 to generate the semiconductor laser beam 5. The semiconductor laser device 20 emits the generated semiconductor laser beam 5 to the laser beam splitting device 30. The single crystal growth apparatus 100 of this example has one laser power source 10 and one semiconductor laser apparatus 20. The number of semiconductor laser beams 5 emitted from the semiconductor laser device 20 is not limited to one, and a plurality of semiconductor laser beams 5 may be divided into M laser beams.

  The laser beam splitting device 30 splits the semiconductor laser beam 5 into M pieces. The laser beam splitting device 30 makes the split semiconductor laser beam 5 enter the optical fibers 41, 42, 43, 44, 45. The laser beam splitting device 30 of this example splits the semiconductor laser beam 5 into M pieces. The laser beam splitting device 30 has first to third splitting methods in order to split the semiconductor laser beam 5 into M pieces.

  The optical fibers 41, 42, 43, 44 and 45 emit M semiconductor laser beams 5 as M heating laser beams 3. The entrance shape of the optical fibers 41, 42, 43, 44, 45 is circular. The incident semiconductor laser beam 5 becomes uniform due to the mutual interference effect by a large number of quartz glass thin tubes constituting the optical fibers 41, 42, 43, 44, 45. On the other hand, in the vicinity of the exit of the optical fibers 41, 42, 43, 44, and 45, the core shape of the optical fiber is made substantially rectangular. As a result, the semiconductor laser light 5 emitted from the optical fibers 41, 42, 43, 44, and 45 becomes the heating laser light 3 having a substantially rectangular shape and a completely uniform laser light intensity in the cross section.

  The laser irradiation heads 51, 52, 53, 54, 55 collect the heating laser light 3 incident from the optical fibers 41, 42, 43, 44, 45 on the raw material rod 1 and the seed crystal rod 2. It is arranged so as to irradiate a plurality of heating laser beams in a radial pattern that requires laser irradiation confirmation and at equal intervals. That is, the laser irradiation heads 51, 52, 53, 54, 55 irradiate the heating laser light 3 from five directions at an angle of about 72 degrees around the raw material rod 1 and the seed crystal rod 2. In the case where the division number M = 5, the uniformity of the light irradiation intensity around the raw material rod 1 and the seed crystal rod 2 is 95% or more. This is because the heating laser beam 3 has a substantially rectangular irradiation shape, and a laser beam having a substantially two-dimensional surface intensity with a substantially rectangular irradiation shape is used. In the heating laser beam 3, a light intensity distribution having a constant light intensity on the two-dimensional surface is referred to as a top flat shape distribution. Thus, the laser irradiation heads 51, 52, 53, 54, and 55 may shape the heating laser beam 3 into a desired irradiation shape.

  The dampers 61, 62, 63, 64 and 65 shown in FIG. 2 have a water cooling mechanism and absorb a part of the heating laser beam 3. The dampers 61, 62, 63, 64, and 65 are provided to face the laser irradiation heads 51, 52, 53, 54, and 55, respectively, with the raw material rod 1 and the seed crystal rod 2 interposed therebetween. For example, the damper 61 absorbs the heating laser beam 3 that has passed through the left and right of the raw material rod 1 and the seed crystal rod 2 in the heating laser beam 3 emitted from the laser irradiation head 51. Thereby, damage inside the single crystal growing apparatus 100 by the laser irradiation head 51 can be prevented.

  Here, the raw material stick | rod 1 is a columnar-shaped stick | rod formed with the material according to the single crystal to grow. The raw material rod 1 and the seed crystal rod 2 are heated by the heating laser beam 3 to form a melting zone 4 on the seed crystal rod 2. For example, the melting temperature of the raw material rod 1 and the seed crystal rod 2 is 300 ° C. to 2000 ° C. The melting zone 4 is a layer in which the raw material rod 1 and the seed crystal rod 2 are melted by the heating laser beam 3 and forms a single crystal corresponding to the material of the raw material rod 1 and the seed crystal rod 2 by cooling. The raw material rod 1 and the seed crystal rod 2 are installed in the quartz tube 6 and fixed to the raw material rod holding part 11 and the single crystal holding part 12, respectively. Since the single crystal growing apparatus 100 of this example does not require the raw material rod 1 and the seed crystal rod 2 to be placed in the crucible, it is possible to grow an extremely high purity single crystal rod without contamination from the crucible. It is also possible to add a trace amount of element to the raw material rod 1.

  The quartz tube 6 is a transparent tube made of quartz. The raw material rod 1 and the seed crystal rod 2 are arranged on the central axis of the quartz tube 6. The quartz tube 6 is filled with a suitable gas according to the material of the raw material rod 1 and the seed crystal rod 2. For example, oxygen gas is supplied to the quartz tube 6 and the inside of the quartz tube 6 is adjusted to a predetermined pressure.

  The raw material rod holding unit 11 holds the raw material rod 1 in the quartz tube 10. The raw material rod holding part 11 rotates the raw material rod 1 counterclockwise with respect to the central axis of the raw material rod 1 in plan view. For example, the raw material rod holding part 11 has a shaft, and the raw material rod 1 is suspended from the shaft by a high melting point wire such as a platinum wire. What is necessary is just to determine the rotational speed of the raw material stick | rod 1 to arbitrary speeds, and is about 10-60 rpm in an example.

  The single crystal holding unit 12 holds the seed crystal rod 2 in the quartz tube 10. The single crystal holding unit 12 rotates the seed crystal rod 2 clockwise with respect to the central axis of the seed crystal rod 2 in plan view. That is, the raw material rod holding unit 11 and the single crystal holding unit 12 rotate so that the rotation direction of the raw material rod 1 and the rotation direction of the seed crystal rod 2 are opposite to each other. What is necessary is just to determine the rotational speed of the seed crystal rod 2 to arbitrary speeds, and is about 10 rpm to 60 rpm in an example. The rotation speed of the seed crystal rod 2 is preferably the same as the rotation speed of the raw material rod 1, but is not limited thereto. By rotating the raw material rod 1 and the seed crystal rod 2, the temperature uniformity of the melting zone 4 is improved. Further, the rotational speed is controlled so that the melting zone 4 is on the central axis of the shaft.

  The raw material rod holding unit 11 and the single crystal holding unit 12 gradually move the holding positions of the raw material rod 1 and the seed crystal rod 2 downward while the melting zone 4 is stabilized at a predetermined temperature. Thus, crystallization is gradually performed in the crystal orientation of the seed crystal from the region above the seed crystal where the heating laser beam 3 is no longer irradiated to the melting zone 4. The moving speed of the raw material rod holding unit 11 and the single crystal holding unit 12 is arbitrarily set according to the characteristics of the single crystal material, the intensity of the heating laser beam 3, and the like.

  In the first embodiment, a laser beam splitting device 30 of the first split method will be described. In the first division method, the semiconductor laser light 5 from the semiconductor laser device 20 is immediately divided into M semiconductor laser lights 5. The greatest merit of the first division method is that the semiconductor laser light 5 from the semiconductor laser device 20 is divided into M laser lights before introducing the semiconductor laser light 5 into the optical fibers 41, 42, 43, 44, and 45. By doing so, it is possible to minimize the influence on the substantially rectangular irradiation shape having the top flat intensity distribution from the optical fibers 41, 42, 43, 44, 45. The top flat intensity distribution and the substantially rectangular shape can be obtained because of the optical fibers 41, 42, 43, 44, and 45. In the first division method, it is preferable to realize the first division method with a small number of optical systems in order to reduce the loss of the laser light intensity in the laser beam dividing device 30.

  FIG. 3 shows an example of the configuration of the semiconductor laser device 20. The semiconductor laser device 20 of this example includes a semiconductor laser element 201 including a semiconductor chip 21, a submount 22 and a heat sink 23.

  The semiconductor chip 21 irradiates the semiconductor laser beam 5. The semiconductor chip 21 has L light emitting points 24 arranged in a line. The semiconductor chip 21 is fixed on the submount 22. In this example, the direction in which the L light emitting points 24 are arranged is the X axis, the direction in which the semiconductor laser light 5 is irradiated is the Z axis, and the direction perpendicular to the X axis and the Z axis is the Y axis.

  The submount 22 is formed of a material having high thermal conductivity such as aluminum nitride, copper tungsten, or artificial diamond. The submount 22 is fixed on the heat sink 23.

  The heat sink 23 absorbs heat generated when the semiconductor chip 21 is driven. The heat sink 23 is a metal heat sink having a high thermal conductivity such as Cu.

  The size of the L light emitting points 24 has a width W1 in the X-axis direction and a height H1 in the Y-axis direction. The L light emitting points 24 are arranged at a pitch P1. The pitch P1 indicates a distance from an end portion on the X axis direction negative side of a certain light emitting point 24 to an end portion on the X axis direction negative side of the adjacent light emitting point 24. That is, one light emitting point 24 is arranged per pitch P1.

  The semiconductor laser beam 5 has a large spread angle in the X-axis direction and the Y-axis direction. Usually, laser light diverges at an divergence angle of 8 to 10 degrees in the X direction and 30 to 70 degrees in the Y direction. Therefore, in order for the semiconductor laser light 5 to enter the optical fibers 41, 42, 43, 44, and 45, it is necessary to convert the semiconductor laser light 5 into parallel light.

  FIG. 4 is a schematic diagram of the optical fiber 40. The optical fiber 40 is an example of the optical fibers 41, 42, 43, 44, 45. The optical fiber 40 has an optical fiber core 46 and an optical fiber cladding 47.

  The structure of the optical fiber 40 is a two-layer structure of an optical fiber core 46 and an optical fiber clad 47 covering its periphery. The refractive index of the optical fiber core 46 is higher than the refractive index of the optical fiber cladding 47. As a result, the semiconductor laser beam 5 propagates through the optical fiber core 46.

Here, a beam parameter product (BPP) is used as an index designed by the semiconductor laser device 20 and the laser beam splitting device 30. BPP is obtained from the following equation.
[Formula 1]
BPP = λ1 × θf
Here, λ1 indicates the diameter of the optical fiber core 46. θf indicates the divergence angle of the optical fiber 40. That is, BPP is the product of the diameter of the optical fiber core 46 and the spread angle θf of the optical fiber 40. BPP gives an important guideline in selecting the number of stacked semiconductor chips 21 of the laser beam splitting device 30, the number of split mirrors, and the width of the split mirror reflecting surface.

When L light emitting points 24 arranged in the X-axis direction are divided into M semiconductor laser beams 5 and incident on M optical fibers 40, the number L of light emitting points is selected so as to satisfy the following expression. .
[Formula 2]
{(L-1) × P1 + W1} × θl ≦ M × BPP

  W1 in the equation (2) is the horizontal length of the light emitting point of the semiconductor laser element. The pitch interval P1 of the semiconductor laser elements indicates the interval between the light emitting point 24 of the semiconductor laser element and the light emitting point 24 of the adjacent semiconductor laser element. θ1 represents a lateral divergence angle of the semiconductor laser light 5 emitted from the light emitting point 24. When the number L of light emitting points in the semiconductor laser device 20 is in the range of the formula (2), the light enters the entrance of the optical fiber 40 with high light energy utilization efficiency. If the BPP is exceeded, the semiconductor laser light 5 damages the optical fiber 40.

  FIG. 5 shows an example of the configuration of the semiconductor laser device 20. The semiconductor laser device 20 includes semiconductor laser elements 201, 202, 203, 204, and 205 stacked in the Y-axis direction.

  The semiconductor laser device 20 can obtain a laser beam intensity sufficient to heat the raw material rod 1 and the seed crystal rod 2 by stacking the semiconductor laser elements 201, 202, 203, 204, 205. The laser beam intensity of the semiconductor laser device 20 must be large enough to heat the raw material rod 1 and the seed crystal rod 2 to about 1000 ° C. to 2000 ° C. However, the raw material rod 1 and the seed crystal rod 2 cannot be heated to about 1000 ° C. to 2000 ° C. with the laser light intensity of one semiconductor laser element 201. In order to heat the raw material rod 1 and the seed crystal rod 2 to about 1000 ° C. to 2000 ° C., a 1 K watt class semiconductor laser device 20 is required. In the semiconductor laser device 20 of the 1 K watt class, the raw material rod 1 and the seed crystal rod 2 can be heated to a desired temperature even if the laser beam is divided into M pieces.

In the semiconductor laser device 20 of this example, N semiconductor laser elements are stacked so as to satisfy the following expression.
[Formula 3]
{(N−1) × Pc + H1} × θv ≦ BPP
Pc represents the stacking interval of the semiconductor laser elements. The stacking interval Pc of the semiconductor laser elements indicates the interval between the light emitting point 24 of a certain semiconductor laser element and the light emitting point 24 of the semiconductor laser element to be stacked. θv represents the vertical divergence angle of the semiconductor laser beam 5 emitted from the light emitting point 24. If the number N of stacked semiconductor laser elements in the semiconductor laser device 20 is in the range of the formula (3), the laser light is guided to the entrance of the optical fiber 40 with high light energy utilization efficiency. If the BPP is exceeded, the semiconductor laser light 5 damages the optical fiber 40.

  FIG. 6A shows an example of a top view of the semiconductor laser device 20. FIG. 6B shows an example of a front view of the semiconductor laser device 20. The semiconductor laser device 20 includes semiconductor laser elements 201, 202, 203, 204, and 205 stacked in a staircase pattern. Further, the semiconductor laser device 20 of this example includes reflection mirrors 25, 26, 27, and 28.

  The semiconductor laser elements 201, 202, 203, 204, and 205 are stacked in a step shape. Laminating stepwise means that the layers are shifted in the X-axis direction and / or Z-axis direction and shifted in the Y-axis direction. For example, the semiconductor laser elements 201, 202, 203, 204, and 205 are stacked at the same pitch in the order of the semiconductor laser elements 201, 202, 203, 204, and 205 from the positive side in the Y-axis direction. Further, the semiconductor laser elements 201, 202, 203, 204, and 205 may be arranged so as to be completely displaced in the XZ plane, or may be arranged so as to partially overlap each other.

  More specifically, the semiconductor laser element 201 irradiates the semiconductor laser beam 5 toward the reflection mirrors 25, 26, 27, and 28. The semiconductor laser element 202 faces the semiconductor laser element 203 with the reflection mirror 25 and the reflection mirror 26 interposed therebetween. The semiconductor laser element 204 is opposed to the semiconductor laser element 205 with the reflection mirror 27 and the reflection mirror 28 interposed therebetween.

  The reflection mirrors 25, 26, 27 and 28 convert the optical path of the semiconductor laser beam 5 emitted from the semiconductor laser elements 202, 203, 204 and 205. In this example, the reflection mirrors 25, 26, 27, 28 are caused to travel straight without changing the optical path of the semiconductor laser light 5 emitted from the semiconductor laser element 201. The reflection mirror 25 and the reflection mirror 26 convert the semiconductor laser light 5 emitted from the semiconductor laser element 202 and the semiconductor laser element 203 in the same direction as the semiconductor laser light 5 of the semiconductor laser element 201, respectively. Further, the reflection mirror 27 and the reflection mirror 28 convert the semiconductor laser light 5 emitted from the semiconductor laser element 204 and the semiconductor laser element 205 in the same direction as the semiconductor laser light 5 emitted from the semiconductor laser element 201, respectively. In this example, the direction in which the semiconductor laser beam 5 is converted is defined as the Z-axis direction for convenience. However, the direction in which the L light emitting points 24 are arranged may be changed as appropriate depending on the direction in which the semiconductor laser elements 201, 202, 203, 204, 205 face. That is, the light emission points 24 of the semiconductor laser elements 201 are aligned in the X-axis direction, and the light emission points 24 of the semiconductor laser elements 202, 203, 204, and 205 are aligned in the Z-axis direction.

  FIG. 7A shows an example of a side view of the semiconductor laser element 201. FIG. 7B shows an example of a top view of the semiconductor laser element 201. The semiconductor laser light 5 emitted from the semiconductor laser element 201 is converted into parallel light by the Y direction collimator 31 and the X direction collimator 32. The Y direction collimator 31 and the X direction collimator 32 are an example of the configuration of the laser beam splitting device 30.

  The Y-direction collimator 31 converts the semiconductor laser light 5 so as to be light parallel to the Z-axis when viewed from the X-axis direction. That is, the semiconductor laser beam 5 spreading in the Y-axis direction becomes light parallel to the Z-axis when viewed from the X-axis direction. The Y-direction collimator 31 has a cylindrical (cylindrical) lens.

  The X-direction collimator 32 converts the semiconductor laser light 5 so as to be parallel to the Z-axis when viewed from the Y-axis direction. That is, the semiconductor laser beam 5 spreading in the X-axis direction becomes light parallel to the Z-axis when viewed from the Y-axis direction. The X-direction collimator 32 has a number of convex lens arrays arranged in the X-axis direction.

  The semiconductor laser light 5 of this example entered the Y direction collimator 31 and then entered the X direction collimator 32. However, the semiconductor laser light 5 may enter the Y-direction collimator 31 after entering the X-direction collimator 32. The semiconductor laser light 5 passes through the Y-direction collimator 31 and the X-direction collimator 32 and becomes laser light parallel to the Z-axis direction.

  FIG. 8 shows an example of a method for dividing the semiconductor laser beam 5. The laser beam splitting device 30 of this example further includes a split mirror 33. The split mirror 33 splits the parallel light of the semiconductor laser light 5 emitted from the X direction collimator 32 into M semiconductor laser lights 5.

  The split mirror 33 has a mirror reflection surface 332 formed on the flat substrate 331. The division mirror 33 divides the semiconductor laser beam 5 into M semiconductor laser beams 5 by providing a number corresponding to the division number M. For example, the split mirror 33 that reflects the semiconductor laser light 5 positioned on the positive side in the X-axis direction with respect to the semiconductor laser light 5 positioned at the center is 45 degrees with respect to the traveling direction of the semiconductor laser light 5 and in the X-axis direction. With the vertical axis inclined to the negative side of Further, the splitting mirror 33 that reflects the semiconductor laser beam 5 positioned on the negative side in the X-axis direction with respect to the semiconductor laser beam 5 positioned at the center is 45 degrees with respect to the traveling direction of the semiconductor laser beam 5 and is in the X-axis direction. With a vertical axis inclined to the positive side of The split mirror 33 in this example is a split mirror of five split mirrors 33a, 33b, 33c, 33d, and 33e, and splits the semiconductor laser light 5 in five directions. In the present specification, when an angle such as 45 degrees is indicated, it is not necessarily required to be exactly 45 degrees, and may be substantially 45 degrees.

  The mirror reflection surface 332 is inclined so that the semiconductor laser light 5 is incident at an angle of 45 degrees with respect to the surface of the mirror reflection surface 332. In other words, the mirror reflecting surface 332 is inclined at 45 degrees with respect to the traveling direction of the semiconductor laser light 5 and the vertical axis to the positive side or the negative side in the X-axis direction. Thereby, the semiconductor laser beam 5 incident on the mirror reflecting surface 332 is bent at a right angle with respect to the traveling direction.

  More specifically, the split mirror 33 is arranged in the order of the split mirrors 33a, 33b, 33c, 33d, and 33e from the positive side of the X axis. The split mirror 33 is arranged in the order of the split mirrors 33c, 33b, 33d, 33a, and 33e from the positive side of the Z axis. The split mirrors 33a, 33b, and 33c in this example bend the semiconductor laser light 5 by 90 degrees to the right with respect to the traveling direction. On the other hand, the split mirrors 33d and 33e bend the semiconductor laser light 5 by 90 degrees to the left with respect to the traveling direction. In this case, the semiconductor laser beam 5 travels in two directions. As described above, the splitting mirror 33 distributes the semiconductor laser light 5 to the left and right, so that an installation space for an optical system that controls the semiconductor laser light 5 for each of the divided semiconductor laser lights 5 can be obtained.

  Since the split mirror 33c is located at the center in the X axis, the semiconductor laser light 5 may be bent 90 degrees to the left with respect to the traveling direction. Further, the semiconductor laser beam 5 may be caused to go straight without installing the split mirror 33c. In this case, the semiconductor laser beam 5 travels in three directions.

Here, a laser beam splitting device 30 that splits a plurality of semiconductor laser beams 5 irradiated from L light emitting points 24 of one semiconductor laser device 20 into M pieces has a split mirror 33 so as to satisfy the following formula. Deploy. D indicates the distance between the split mirrors 33 in the X-axis direction.
[Formula 4]
D = n × d1
Here, n is an arbitrary integer. D1 indicates the width of each of the semiconductor laser beams 5 divided into M pieces in the X-axis direction. D shown in FIG. 8 indicates the distance between the center lines of the split mirror 33a and the split mirror 33c. d1 satisfies the following equation.
[Formula 5]
d1 = {(L−1) × P1 + W1} / M

  The split mirror 33 may be provided with a mechanism such as an actuator in order to move without changing the angle with respect to the incident semiconductor laser light 5. When the split mirror 33 includes an actuator, the optical path length of each of the M semiconductor laser beams 5 can be freely adjusted. The longer the optical path length of the semiconductor laser light 5 is, the larger the loss of the semiconductor laser light 5 is. Therefore, the optical path length of the semiconductor laser light 5 is preferably equal among the M semiconductor laser lights 5 divided.

  FIG. 9 shows an example of an attenuation method of the semiconductor laser light 5. In this example, the configuration of the laser beam splitting device 30 further includes an attenuation mirror 34, a damper unit 35, a first condenser lens 36, and a second condenser lens 37.

  The attenuation mirror 34 attenuates the incident semiconductor laser light 5 to equalize the laser light intensities of the M semiconductor laser lights 5. For example, the attenuation mirror 34 reflects at least a part of the M semiconductor laser beams 5 divided by the division mirror 33 and passes the other part. Thereby, the attenuation mirror 34 freely adjusts the laser beam intensity of the semiconductor laser beam 5. A plurality of attenuation mirrors 34 may be provided according to the number of division mirrors 33.

  The damper part 35 has a water cooling mechanism and is installed at a position where the reflected light from the attenuation mirror 34 enters. Thereby, the damper part 35 absorbs the reflected light from the attenuation mirror 34. Further, when a plurality of attenuation mirrors 34 are provided, the damper unit 35 may be provided in common for the plurality of attenuation mirrors 34.

  The first condenser lens 36 and the second condenser lens 37 condense the semiconductor laser light 5 attenuated by the attenuation mirror 34 and make it incident on the optical fiber 40. The 1st condensing lens 36 and the 2nd condensing lens 37 satisfy | fill the conditions of BPP of the optical fiber 40, and are arrange | positioned. The lens for condensing the semiconductor laser light 5 on the optical fiber 40 is composed of the first condenser lens 36 and the second condenser lens 37, which are the minimum number of two condenser lenses. A combination of optical lenses may also be used.

  The attenuation mirror 34 may include a mechanism such as an actuator in order to move without changing the angle between the M semiconductor laser beams 5 incident thereon and the vertical axis of the attenuation mirror 34. When the attenuation mirror 34 includes an actuator, the attenuation rate of each of the M semiconductor laser beams 5 divided can be freely adjusted. Therefore, the laser beam intensity of the M semiconductor laser beams 5 divided can be controlled to be uniform.

  FIG. 10 shows a simulation experiment result in Example 1 of the semiconductor laser beam 5 divided into M pieces. The laser division number M in this example is 5.

  The experimental result of this example shows the semiconductor laser beam 5 incident on the optical fiber 40 by the laser beam splitting device 30 according to the first embodiment. The laser beam splitting device 30 according to the first embodiment is different from the laser beam splitting device 30 in that the Y-direction collimator 31, the X-direction collimator 32, the split mirror 33, the attenuation mirror 34, the damper unit 35, the first condenser lens 36, and the second. This is a case where the condenser lens 37 is provided. The diameter λ1 of the optical fiber core 46 in this example is 0.8 mmφ. From the result of the simulation experiment, it was proved that the divided semiconductor laser light 5 was stored in the optical fiber core 40 in any of the optical fibers 41, 42, 43, 44, 45.

  As described above, the single crystal growing apparatus 100 according to the first embodiment can irradiate the M laser fibers 5 with uniform intensity on the entrances of the M optical fibers 40. Since the single crystal growth apparatus 100 has an optical system in which the semiconductor laser light 5 is controlled within the BPP of the optical fiber 40, the loss of the semiconductor laser light 5 is small and uniform laser light intensity can be achieved.

[Example 2]
FIG. 11 shows a method for dividing the semiconductor laser beam 5 according to the second embodiment. The laser beam splitting device 30 of this example splits the semiconductor laser beam 5 in one direction and takes it out. The downstream attenuating mirror 34, damper 35, first condenser lens 36, and second condenser lens 37 may have the same configuration as in the first embodiment.

  The split mirror 33 has a mirror reflection surface 332 formed on the flat substrate 331. The division mirror 33 divides the semiconductor laser beam 5 into M semiconductor laser beams 5 by providing a number corresponding to the division number M. For example, when dividing into M semiconductor laser beams 5 in the X-axis direction, all the split mirrors 33 are tilted 45 degrees with respect to the traveling direction of the semiconductor laser beam 5 and positive or negative in the X-axis direction. With a vertical axis. In the split mirror 33 of this example, the five split mirrors of the split mirrors 33a, 33b, 33c, 33d, and 33e are perpendicular to the positive direction in the X-axis direction by 45 degrees with respect to the traveling direction of the semiconductor laser light 5. Has an axis.

  More specifically, the split mirror 33 is arranged in the order of the split mirrors 33a, 33b, 33c, 33d, and 33e from the positive side of the X axis. The split mirror 33 is arranged in the order of the split mirrors 33a, 33b, 33c, 33d, and 33e from the positive side direction of the Z axis. All of the split mirrors 33a, 33b, 33c, 33d, and 33e in this example bend the semiconductor laser light 5 by 90 degrees to the left with respect to the traveling direction. Further, the split mirrors 33a, 33b, 33c, 33d, and 33e may bend the semiconductor laser light 5 90 degrees to the right with respect to the traveling direction. That is, the M semiconductor laser beams 5 travel in one direction. The arrangement of the split mirror 33 in this example makes it easy to uniformly control the respective optical path lengths of the M semiconductor laser beams 5 from the exit from the X-direction collimator 32 to the incidence on the attenuation mirror 34. In this case, the split mirror 33 of this example is disposed so as to satisfy the formula (4) and the formula (5).

  FIG. 12 shows an example of the configuration of the first condenser lens 36 and the second condenser lens 37. The first condensing lens 36 and the second condensing lens 37 each have an integral structure type lens array.

  Since the 1st condensing lens 36 and the 2nd condensing lens 37 have an integral structure type lens array, the space | interval of lenses can be made small rather than forming a lens array separately. That is, even when the interval between the M semiconductor laser beams 5 is narrowed, it is easy to collect light on the optical fiber 40. Therefore, if the first condenser lens 36 and the second condenser lens 37 of this example are used, it is easy even when M semiconductor laser beams 5 are emitted in one direction as in the split mirror 33 of the second embodiment. In addition, M semiconductor laser beams 5 can be condensed on the optical fibers 41, 42, 43, 44, 45. For example, the first condenser lens 36 and the second condenser lens 37 have a plurality of spherical lenses and a plurality of cylindrical lenses.

[Example 3]
FIG. 13 illustrates an example of the configuration of the laser beam splitting device 30 according to the third embodiment. The laser beam splitting device 30 of this example includes a triangular prism mirror 38 instead of the split mirror 33.

  The triangular prism mirror 38 splits the semiconductor laser light 5 into M semiconductor laser lights 5. The triangular mirror 38 includes a triangular substrate 381 and a mirror reflecting surface 382.

The triangular substrate 381 has a triangular prism shape with a hypotenuse length of T. The mirror reflecting surface 382 is formed on the slope of the length T of the triangular substrate 381. The mirror reflecting surface 382 of the present example has a vertical axis that is inclined 45 degrees with respect to the traveling direction of the semiconductor laser beam 5 and that is inclined to the positive side or the negative side in the X-axis direction. Here, the length T of the hypotenuse satisfies the following expression.
[Formula 6]
T = d1 × √2

  More specifically, the triangular prism mirror 38 of this example includes two triangular prism mirrors 38a and 38b. The triangular prism mirror 38 is arranged in the order of the triangular prism mirrors 38a and 38b from the positive side of the X axis. The triangular prism mirror 38 is arranged in the order of the triangular prism mirrors 38a and 38b from the positive side of the Z axis. In other words, the triangular prism mirror 38a and the triangular prism mirror 38b are arranged so as to be shifted from each other in the X-axis direction and the Z-axis direction. The triangular prism mirror 38a divides the semiconductor laser light 5 into the positive side direction and the negative side direction of the X axis. Further, the triangular prism mirror 38b divides the semiconductor laser light 5 into the positive side direction and the negative side direction of the X axis. Thereby, the triangular prism mirror 38 takes out four of the five semiconductor laser beams 5 from the semiconductor laser beam 5. The remaining one semiconductor laser beam 5 passes through the triangular prism mirror 38 without passing through it. Further, the remaining one semiconductor laser beam 5 may be bent to either the positive side or the negative side in the X-axis direction by the split mirror 33.

  The attenuation mirror 34, the damper portion 35, the first condenser lens 36, and the second condenser lens 37 may have the same configuration as that of the first embodiment. As described above, the first to third embodiments satisfying the BPP of the optical fiber 40 have been shown in the first to third embodiments. However, in addition to this embodiment, the modification example of the split mirror arrangement method satisfying the BPP of the optical fiber 40 is shown. May be included.

[Example 4]
FIG. 14 illustrates an exemplary configuration of a laser beam splitting device 30 according to the fourth embodiment. The laser beam splitting device 30 of this example includes a laser beam splitting device composed of a total reflection mirror 33 and a half mirror 39.

  The laser beam splitting device splits the semiconductor laser beam 5 into M pieces. The laser beam splitting apparatus of this example splits one semiconductor laser beam 5 into three using total reflection mirrors 33f and 33g and half mirrors 39f and 39g. However, the laser beam splitting device may split the semiconductor laser beam 5 into an arbitrary number by changing the number of total reflection mirrors 33 and half mirrors 39.

  The half mirror 39 bends a part of the incident semiconductor laser light 5 in a predetermined direction and transmits the other part. That is, the division number M of the semiconductor laser beam 5 is determined according to the number of the half mirrors 39. The half mirror 39 has a mirror semi-transmissive surface 392 formed on the flat substrate 391. The half mirror 39 is disposed such that the vertical axis of the mirror semi-transmissive surface 392 forms 45 degrees with respect to the traveling direction of the incident semiconductor laser beam 5. The half mirror 39 bends the semiconductor laser light 5 by 90 degrees to the right with respect to the traveling direction. The reflectivities of the half mirrors 39f and 39g are arbitrarily set according to the number of the half mirrors 39.

  The total reflection mirror 33 reflects the semiconductor laser light 5 reflected by the half mirror 39 in an arbitrary direction. As the reflectivity, a multilayer film having a reflectivity close to 100%, an aluminum or gold thin film is used. The total reflection mirror 33 has a mirror reflection surface 332 formed on the flat substrate 331. For example, the mirror reflection surface 332 has a vertical axis inclined by 45 degrees with respect to the traveling direction of the semiconductor laser light 5 reflected by the half mirror 39. When the half mirror 39 bends the semiconductor laser light 5 90 degrees to the right with respect to the traveling direction, the total reflection mirror 33 of this example bends the semiconductor laser light 5 90 degrees to the left with respect to the traveling direction. The semiconductor laser beam 5 is reflected in the same direction as the semiconductor laser beam 5 transmitted through the half mirror 39. The total reflection mirrors 33f and 33g are arranged corresponding to the half mirrors 39f and 39g so as to reflect the semiconductor laser light 5 reflected by the half mirrors 39f and 39g, respectively. The total reflection mirror 33 may reflect the semiconductor laser light 5 transmitted through the half mirror 39.

[Example 5]
FIG. 15 illustrates an exemplary configuration of a laser beam splitting device 30 according to the fifth embodiment. The laser beam splitting device 30 of this example includes a splitting prism 90.

  The dividing prism 90 divides the semiconductor laser light 5 incident from the semiconductor laser device 20 into M pieces. The split prism 90 includes a multilayer film 902 with high reflectivity, an aluminum metal film, or a gold thin film on the slope of the prism base 901. The shape of the split prism 90 in this example is a quadrangular pyramid. The split prism 90 is disposed at a position where the semiconductor laser light 5 enters from the apex of the quadrangular pyramid. Thereby, the semiconductor laser beam 5 is emitted from the four surfaces adjacent to the apex on which the semiconductor laser beam 5 is incident. The shape of the split prism 90 may be appropriately changed according to the number of the semiconductor laser beams 5 to be split. The laser beam splitting device 30 can simplify the optical system by using the splitting prism 90.

[Example 6]
FIG. 16 illustrates an example of a configuration of a laser beam splitting device 30 according to the sixth embodiment. The laser beam splitting device 30 of this example includes a splitting prism 91.

  The dividing prism 91 divides the semiconductor laser light 5 incident from the semiconductor laser device 20 into M pieces. The split prism 91 includes a multilayer film 912 having a high reflectivity, an aluminum metal film, or a gold thin film on the slope of the prism base 911. The split prism 91 of this example includes a polyhedral split prism 91a formed in a cubic split prism 91b. The dividing prism 91 divides the semiconductor laser light 5 in an arbitrary direction by adjusting the shapes of the dividing prisms 91a and 91b. The shape of the split prism 91a in this example is a quadrangular pyramid. For example, the splitting prism 91 is arranged so that the semiconductor laser light 5 incident on the splitting prism 91b is incident on the apex of the M pyramid of the splitting prism 91a. Thereby, the splitting prism 91a splits the incident semiconductor laser light 5 into M pieces.

[Example 7]
FIG. 17 shows an example of a method of incidence on the laser beam splitting device 30 according to the first splitting method. The laser beam splitting device 30 of this example includes a Y-direction collimator 31, an X-direction collimator 32, an optical fiber 48, and a condenser lens 49.

  The laser beam splitting device 30 causes the semiconductor laser beam 5 emitted from the semiconductor laser device 20 to enter one optical fiber 48 via a condenser lens 49. Thereafter, the semiconductor laser light 5 emitted from the optical fiber 48 is converted into parallel semiconductor laser light 5 by passing through the Y-direction collimator 31 and the X-direction collimator 32. The order of the Y direction collimator 31 and the X direction collimator 32 may be changed. Further, the Y-direction collimator 31 and the X-direction collimator 32 divide the emitted parallel light into M semiconductor laser beams 5 by the lens systems disclosed in the first to sixth embodiments. Since the laser beam splitting device 30 of the present example can bend the semiconductor laser beam 5 from the semiconductor laser device 20 in an arbitrary direction inside the laser beam splitting device 30, the laser power source 10, the semiconductor laser device 20, and the laser beam The degree of freedom of arrangement of the dividing device 30 is improved.

[Example 8]
FIG. 18 shows an example of a method of incidence on the laser beam splitting device 30 according to the second splitting method. In the second division method, the semiconductor laser light 5 emitted from the semiconductor laser device 20 is divided by a plurality of half mirrors. The single crystal growth apparatus 100 of this example has one semiconductor laser apparatus 20. The division number M is five. The laser beam splitting device 30 of this example includes a Y direction collimator 31, an X direction collimator 32, an attenuation mirror 34, a first condenser lens 36, a second condenser lens 37, and a half mirror 39.

  The laser beam splitting device 30 causes the semiconductor laser beam 5 emitted from the semiconductor laser device 20 to enter the Y direction collimator 31 and the X direction collimator 32. The Y direction collimator 31 and the X direction collimator 32 convert the semiconductor laser light 5 into parallel laser light.

  The half mirror 39 divides the parallel semiconductor laser light 5 converted by the Y direction collimator 31 and the X direction collimator 32 into M pieces. The half mirror 39 has a reflective film having a multilayer film structure. Thereby, the half mirror 39 bends a part of the incident semiconductor laser beam 5 in a predetermined direction and transmits the other part. The half mirror 39 is arranged so that the vertical axis of the half mirror 39 forms 45 degrees with respect to the traveling direction of the incident semiconductor laser beam 5. The half mirror 39 bends the semiconductor laser light 5 by 90 degrees to the left with respect to the traveling direction. The half mirror 39 of this example includes half mirrors 39a, 39b, 39c, 39d, and 39e. The reflectivities of the half mirrors 39a, 39b, 39c, 39d, and 39e are 15%, 18.4%, 23.5%, 32.8%, and 54% from the half mirror 39 close to the optical fiber 48, respectively.

  The loss of each half mirror 39 in this example is 3%. In this case, the semiconductor laser beam 5 having substantially the same reflection intensity within 15 ± 0.1% is obtained as the reflection intensity of the semiconductor laser beam 5 divided into five. Further, the intensity of the semiconductor laser beam 5 transmitted through the five half mirrors 39 is suppressed to 2% or less.

  The attenuation mirror 34 adjusts the reflection intensity of the five semiconductor laser beams 5 reflected by the half mirror 39. The attenuation mirror 34 is arranged so that the vertical axis of the attenuation mirror 34 forms 45 degrees with respect to the traveling direction of the semiconductor laser light 5 from the half mirror 39. The attenuation mirror 34 may include a mechanism such as an actuator in order to move without changing the angle between the M semiconductor laser beams 5 incident thereon and the vertical axis of the attenuation mirror 34. The attenuation mirror 34 of this example is configured by attenuation mirrors 34a, 34b, 34c, 34d, and 34e corresponding to the half mirrors 39a, 39b, 39c, 39d, and 39e. The attenuation mirror 34 does not have to be provided with all of the half mirrors 39a, 39b, 39c, 39d, and 39e.

  The first condensing lens 36 and the second condensing lens 37 condense the M semiconductor laser beams 5 onto the M optical fibers 40. The laser beam splitting device 30 is designed to satisfy the BPP of the substantially square optical fiber 40.

  The laser beam splitting device 30 according to the second splitting method is an effective method when the semiconductor laser device 20 does not have a stacked structure of the semiconductor chips 21. In the second division method, the configuration of the laser beam dividing apparatus 30 can be simplified.

[Example 9]
FIG. 19 shows an example of the configuration of the laser beam splitting device 30 according to the second splitting method. The single crystal growth apparatus 100 of this example has one semiconductor laser apparatus 20. The division number M is five. The laser beam splitting device 30 of this example further includes half mirrors 39a, 39b, 39c, 39d, 39e and an optical fiber 48.

  The laser beam splitting device 30 causes the semiconductor laser beam 5 emitted from the semiconductor laser device 20 to enter one optical fiber 48 via a condenser lens 49. Thereafter, the semiconductor laser light 5 emitted from the optical fiber 48 is converted into parallel semiconductor laser light 5 by passing through the Y-direction collimator 31 and the X-direction collimator 32. The order of the Y direction collimator 31 and the X direction collimator 32 may be changed. The method for dividing the semiconductor laser light 5 emitted from the Y-direction collimator 31 and the X-direction collimator 32 may be the same as that in the eighth embodiment.

  20 and 21 show an example of a split fiber 80 according to the third split method. In the third division method, the semiconductor laser beam 5 is divided using a division fiber 80 instead of using a division mirror.

  The laser beam splitting device 30 of this example includes a split fiber 80. The split fiber 80 has M exit ports 82 for splitting and emitting the semiconductor laser light 5 incident on the entrance port 81. The split fiber 80 of this example has one entrance port 81 and two exit ports 82. Further, if the split fiber 80 is used, the semiconductor laser light 5 incident from one incident port 81 can be emitted from the five emission ports 82. By using the dividing fiber 80, the lens system of the laser beam dividing apparatus 30 is simplified. In addition, the split fiber 80 of FIG. 20 shows the case where the output port 82 is circular. On the other hand, the split fiber 80 of FIG. 21 shows a case where the exit port 82 is substantially rectangular.

[Example 10]
FIG. 22 shows an example of the configuration of the laser irradiation head 50. The laser irradiation head 50 is an example of the laser irradiation heads 51, 52, 53, 54, and 55. The laser irradiation head 50 of this example includes a condenser lens 57 and a folding mirror 58.

  The condensing lens 57 condenses the heating laser light 3 incident from the optical fiber 40 on the folding mirror 58. The folding mirror 58 folds the heating laser beam 3 collected by the condenser lens 57 toward the raw material rod 1 and the seed crystal rod 2. An example of a substantially square irradiation of 3 mm × 8 mm having a top-flat irradiation intensity distribution is shown. Since the optical fiber 40 has a fiber allowable radius R1, the installation area of the single crystal growing apparatus 100 may be increased. However, in the single crystal growing apparatus 100 of this example, by providing the laser irradiation head 50, the direction of the optical fiber 40 is perpendicular to the irradiation direction of the heating laser beam 3 to the raw material rod 1 and the seed crystal rod 2. Can be placed. Therefore, it is possible to prevent an increase in the installation area of the optical bench 56 due to the restriction of the optical fiber allowable radius R1 of the optical fiber 40.

[Comparative Example 1]
FIG. 23 shows a top view of the single crystal growth apparatus 500 according to Comparative Example 1. The single crystal growing apparatus 500 of this example does not have the folding mirror 58. In the single crystal growth apparatus 500, five laser irradiation heads 551, 552, 553, 554, and 555 must be arranged in a horizontal plane in order to keep the limit of the fiber allowable radius R1. Therefore, the single crystal growing apparatus 500 needs to increase the ground contact area of the optical bench 56 in consideration of the fiber allowable radius R1. For example, when the fiber allowable radius R1 has a curvature of 30 cm, the optical bench 56 needs to have a size of about 150 cm × 150 cm.

  FIG. 24 shows an example of a top view of the single crystal growing apparatus 100. The single crystal growing apparatus 100 of this example includes a laser irradiation head 50 having a folding mirror 58. Therefore, the laser irradiation head 50 is disposed in parallel with the raw material rod 1 and the seed crystal rod 2. By providing the laser irradiation head 50 in a direction parallel to the single raw material rod 1 and the seed crystal rod 2, the restriction on the fiber allowable radius R1 of the optical fiber 40 introduced into the laser irradiation head 50 is relaxed. Therefore, five laser irradiation heads 50 can be installed if the size of the optical bench 56 is about 70 cm × 70 cm regardless of the fiber allowable radius R1. As a result, the installation area of the optical stage 56 related to the single crystal growth apparatus 100 can be reduced by about 75% compared to the installation area of the optical stage 56 of the single crystal growth apparatus 500. The single crystal growth apparatus 100 of the present example is greatly reduced in cost by reducing the installation space.

[Example 11]
FIG. 25 shows an example of the configuration of the single crystal growing apparatus 100. The single crystal growing apparatus 100 of this example has a ceiling part 59 of an optical bench.

  The ceiling part 59 is located on the side of the raw material bar holding part 11 for suspending the raw material bar 1 from the optical bench 56. For example, the ceiling part 59 is located above the laser irradiation heads 51, 52, 53, 54, 55. The ceiling part 59 fixes the laser irradiation heads 51, 52, 53, 54 and 55. Moreover, the ceiling part 59 may fix other structures with which the single crystal growing apparatus 100, such as the dampers 61, 62, 63, 64, and 65, are provided at a predetermined position. Thereby, the single crystal growth apparatus 100 according to the sixth embodiment has an advantage that fewer parts are fixed to the optical bench 56 than the single crystal growth apparatus 100 according to the first embodiment. Since the single crystal growing apparatus 100 of this example has the ceiling portion 59, a space for installing the camera for observing the melting zone 4, a spare raw material rod, a spare quartz tube, and the like on the optical bench 56 can be easily secured.

  As described above, the single crystal growth apparatus 100 according to the present specification only needs to provide at least one laser power source 10, so that the cost of the laser power source 10 is reduced. In addition, since the single crystal growth apparatus 100 only needs to provide at least one semiconductor laser apparatus 20, the cost and incidental facilities for the semiconductor laser apparatus 20 are greatly reduced. Furthermore, since it is not necessary to use a plurality of semiconductor laser devices 20, the system for controlling the driving of the semiconductor laser device 20 can be simplified. And by having the folding mirror 58, the installation space of the single crystal growing apparatus 100 can be reduced.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.

DESCRIPTION OF SYMBOLS 1 ... Raw material rod, 2 ... Seed crystal rod, 3 ... Heating laser beam, 4 ... Melting zone, 5 ... Semiconductor laser beam, 6 ... Quartz tube, 11 ... Raw material Rod holder, 12 ... single crystal holder, 10 ... laser power supply, 20 ... semiconductor laser device, 201, 202, 203, 204, 205 ... semiconductor laser element, 21 ... semiconductor chip , 22 ... submount, 23 ... heat sink, 24 ... light emitting point, 25, 26, 27, 28 ... reflection mirror, 30 ... laser beam splitting device, 31 ... Y-direction collimator , 32 ... X direction collimator, 33 ... Total reflection mirror, 331 ... Planar substrate, 332 ... Mirror reflection surface, 34 ... Attenuation mirror, 35 ... Damper part, 36 ... First condenser lens, 37... Second condenser lens, 38. Mirror ... 381 ... Triangular substrate, 382 ... Mirror reflection surface, 39 ... Half mirror, 391 ... Planar substrate, 392 ... Mirror semi-transmission surface, 40, 41, 42, 43, 44, 45 ... Optical fiber, 46 ... Optical fiber core, 47 ... Optical fiber cladding, 48 ... Optical fiber, 49 ... Condensing lens, 50, 51, 52, 53, 54, 55 ..Laser irradiation head, 56... Optical bench, 57... Condensing lens, 58 .. folding mirror, 59 .. ceiling part, 61, 62, 63, 64, 65. ... Split fiber, 81 ... Entrance, 82 ... Exit, 90 ... Split prism, 91 ... Split prism, 100 ... Single crystal growth device, 500 ... Single crystal growth Equipment, 501 ... Raw material bar, 510 ... The power source, 520... Semiconductor laser, 540... Optical fiber, 550, 551, 552, 553, 554, 555. ... Prism substrate, 912 ... Multilayer film

Claims (29)

In a single crystal growth apparatus for growing a single crystal from a raw material rod,
A semiconductor laser device having a laser power source and emitting semiconductor laser light based on the power supplied by the laser power source;
A laser beam splitting device for splitting the semiconductor laser beam into M;
A single crystal growth apparatus comprising: a laser irradiation head that irradiates the M semiconductor laser beams toward a raw material rod. There are M incident apertures and M exit apertures, and the M semiconductor laser beams are incident on the M incident apertures from the laser beam splitting device, and the M semiconductor laser beams are transmitted to the M incident apertures. The laser irradiation head further includes M optical fibers that exit from the M exit ports,
The laser beam splitting device
A collimator lens that converts the semiconductor laser light from the semiconductor laser device into parallel light;
A plurality of split mirrors for splitting the semiconductor laser light into M semiconductor laser lights;
A plurality of attenuation mirrors for equalizing the laser light intensities of the M semiconductor laser beams;
The single crystal growing apparatus according to claim 1, further comprising: a condensing lens that condenses the M semiconductor laser beams onto the M optical fibers. The semiconductor laser device has N semiconductor laser elements,
Each of the N semiconductor laser elements includes a semiconductor chip having a width W1 in the first direction and including L light emitting points arranged in a row at a pitch interval P1 in the first direction.
The single crystal growth apparatus according to claim 2, wherein the N semiconductor laser elements are arranged so as to be shifted in a second direction perpendicular to the first direction. The N semiconductor laser elements are arranged in a staircase pattern shifted in the first direction, and have reflection mirrors that reflect the semiconductor laser beams emitted from the N semiconductor laser elements in a predetermined direction. The single crystal growing apparatus according to claim 3. N is
{(N−1) × Pc + H1} × θv ≦ λc × θf
The filling,
Pc represents the pitch interval in the second direction of the N semiconductor laser elements,
H1 represents the height of the light emitting point in the second direction,
θv represents the divergence angle of the semiconductor laser light in the second direction,
λc represents the core diameter of the optical fiber,
The single crystal growth apparatus according to claim 4, wherein θf represents a divergence angle of the optical fiber. L is
{(L-1) × P1 + W1} × θ1 ≦ M × λc × θf
The filling,
The single crystal growth apparatus according to claim 4, wherein θl represents a divergence angle of the light emitting point in the first direction. The collimator lens is
A cylindrical lens that converts the semiconductor laser light into light perpendicular to the second direction when viewed from the first direction;
The single crystal growing apparatus according to any one of claims 3 to 6, further comprising: a lens array that converts the semiconductor laser light into light perpendicular to the first direction when viewed from the second direction. The plurality of split mirrors are:
The single crystal growing apparatus according to any one of claims 3 to 7, wherein in each of the M semiconductor laser beams, an optical path length from the light emitting point to the condenser lens is a constant distance. . The plurality of split mirrors are:
When each interval in the first direction in the plurality of divided mirrors is D,
D = n × {(L−1) × P1 + W1} / M
The filling,
The single crystal growing apparatus according to any one of claims 3 to 8, wherein n is an integer. The plurality of split mirrors are:
Dividing the semiconductor laser light emitted from the semiconductor laser device into M semiconductor laser lights in the first direction;
In the first direction, the plurality of split mirrors that reflect the semiconductor laser light located on the positive side of the first direction with respect to the semiconductor laser light located in the center of the semiconductor laser light with respect to the traveling direction of the semiconductor laser light A mirror reflecting surface having a vertical axis inclined to the negative side of the first direction at about 45 degrees,
In the first direction, the plurality of split mirrors that reflect the semiconductor laser light located on the negative side of the first direction with respect to the semiconductor laser light located in the center of the semiconductor laser light with respect to the traveling direction of the semiconductor laser light The single crystal growing apparatus according to claim 3, further comprising a mirror reflecting surface having a vertical axis inclined to the positive side in the first direction at approximately 45 degrees. The plurality of split mirrors are:
A mirror reflecting surface having a vertical axis inclined to the positive side or the negative side of the first direction at approximately 45 degrees with respect to the traveling direction of the semiconductor laser light;
10. The single laser device according to claim 3, wherein the semiconductor laser beam emitted from the semiconductor laser device is divided into M semiconductor laser beams emitted in the positive side or the negative side direction of the first direction. 10. Crystal growth device. The single crystal growing apparatus according to claim 10 or 11, wherein the plurality of split mirrors have an actuator that moves without changing an angle of the vertical axis with respect to a traveling direction of the semiconductor laser light. The single crystal growing apparatus according to any one of claims 2 to 9, wherein the plurality of split mirrors have a triangular prism shape with a hypotenuse length of T, and a mirror reflecting surface on the triangular prism-shaped slope. The length T of the hypotenuse is
T = {(L−1) × P1 + W1} × √2 / M
The single crystal growing apparatus according to claim 13, wherein The plurality of attenuation mirrors are located between the plurality of split mirrors and the condenser lens,
The single crystal growing apparatus according to claim 2, wherein at least a part of the semiconductor laser light from the plurality of split mirrors is reflected. The single crystal growing apparatus according to claim 15, wherein the plurality of attenuation mirrors include a mirror reflecting surface having a vertical axis inclined approximately 45 degrees with respect to a traveling direction of the semiconductor laser light from the plurality of split mirrors. The single crystal growing apparatus according to claim 16, wherein the plurality of attenuation mirrors include an actuator that moves without changing an angle of the vertical axis with respect to a traveling direction of the semiconductor laser light. The said condensing lens has a lens array which integrally formed the spherical lens and several cylindrical lens which condense the said M semiconductor laser beams to M optical fibers, respectively. The single crystal growing apparatus according to item. The laser beam splitting device
A lens system for condensing semiconductor laser light from the semiconductor laser device;
One optical fiber for propagating the semiconductor laser light collected by the lens system;
The single crystal growth apparatus according to claim 1, further comprising: a plurality of split mirrors that split the semiconductor laser light from the one optical fiber into M pieces. The laser beam splitting device
A collimator lens that collimates the semiconductor laser light from the semiconductor laser device;
The single crystal growing apparatus according to claim 1, further comprising: a plurality of half mirrors that divide the semiconductor laser light from the collimator lens into M pieces. The laser beam splitting device
A lens system for condensing semiconductor laser light from the semiconductor laser device;
One optical fiber for propagating the semiconductor laser light collected by the lens system;
The single crystal growing apparatus according to claim 1, further comprising: a plurality of half mirrors that divide the semiconductor laser light from the one optical fiber into M pieces. The laser beam splitting device
The single crystal growing apparatus according to any one of claims 1 to 4, comprising a plurality of half mirrors and a plurality of total reflection mirrors. The laser beam splitting device
A plurality of half mirrors having at least one upstream half mirror and at least one downstream half mirror;
A plurality of total reflection mirrors and
Either one of the semiconductor laser light transmitted through the upstream half mirror and the semiconductor laser light reflected from the upstream half mirror is incident on the plurality of total reflection mirrors,
2. The single crystal growing apparatus according to claim 1, wherein the other of the semiconductor laser light transmitted through the upstream half mirror and the semiconductor laser light reflected from the upstream half mirror is incident on the downstream half mirror. . The laser beam splitting device
The single crystal growing apparatus according to claim 1, further comprising a pyramid-shaped split prism that splits the semiconductor laser light incident from the apex into a plurality of pieces. The laser beam splitting device
A lens system for condensing semiconductor laser light from the semiconductor laser device;
The semiconductor laser beam has one incident port and M exit ports, and the semiconductor laser beam condensed by the lens system is incident on the one incident port, and the semiconductor that is incident from the M exit ports The single crystal growing apparatus according to any one of claims 1 to 4, further comprising: a divided fiber that divides the laser beam into M beams and emits the laser beam. The single crystal growing apparatus according to claim 25, wherein the shape of the M outlets is substantially square. The laser irradiation head includes:
The single crystal growth apparatus according to any one of claims 1 to 24, further comprising a folding mirror that bends the traveling direction of the incident semiconductor laser light substantially perpendicularly. M laser irradiation heads that irradiate the M semiconductor laser beams toward the raw material rod;
M dampers that absorb at least part of the M semiconductor laser beams;
25. The ceiling according to any one of claims 1 to 24, further comprising: a ceiling portion positioned above the M laser irradiation heads and fixing the M laser irradiation heads and the M dampers. Single crystal growth equipment. The single crystal growth apparatus according to any one of claims 1 to 27, comprising one each of the semiconductor laser device and the laser beam splitting device.