JP2008283064A - Semiconductor laser device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor laser device capable of improving yield and maintaining effective laser characteristics. <P>SOLUTION: The semiconductor laser device 1 is provided with a semiconductor laser array 11, a reinforcing part 12, an insulating layer 13, and an electrode member 14 on a heat sink 10. The reinforcing part 12 is formed on an area different from that of the semiconductor laser array 11 on the heat sink 10 and composed of a material whose coefficient of linear expansion is smaller than that of the heat sink 10. At the time of joining the semiconductor laser array 11 to the heat sink 10 or during high-temperature operation, thermal stress to be applied from the heat sink 10 to the semiconductor laser array 11 is reduced without interrupting heat conduction from the semiconductor laser array 11 to the heat sink 10. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a semiconductor laser device including a semiconductor laser element mounted on a heat dissipation member such as a heat sink.

  Conventionally, in application equipment in which a semiconductor laser is used, problems related to heat generation have become serious, and the use of semiconductor lasers in various fields is limited. This problem is related to the large amount of heat generated per unit area of the semiconductor laser, and the temperature inside the semiconductor laser rises due to thermal circulation, resulting in a decrease in light emission output, light emission efficiency and lifetime, as well as the oscillation wavelength. This is a factor that causes longer wavelengths.

For this reason, in order to increase the exhaust heat efficiency of the semiconductor laser, a technique of joining the semiconductor laser to a heat sink having high thermal conductivity is used. However, since the difference in coefficient of linear expansion between the heat sink and the semiconductor laser is large, a large thermal stress is generated during mounting or high temperature operation. In particular, a semiconductor laser array or the like formed on a fragile GaAs substrate cannot withstand this thermal stress and may be destroyed.
Japanese Patent Laid-Open No. 01-135088 JP-A-63-141386 JP 2006-68765 A

  Therefore, a technique has been proposed in which a submount for relaxing stress is interposed between the semiconductor laser and the heat sink (for example, Patent Documents 1 and 2). Patent Document 3 proposes a technique for absorbing stress by joining a heat sink and a semiconductor laser using solder mixed with a plurality of metal particles.

  However, in the configuration of the above-mentioned patent document, the thermal conductivity is deteriorated as compared with the case where the semiconductor laser is directly bonded to the heat sink. For this reason, particularly when large heat is generated as in an array laser, the exhaust heat becomes insufficient, the laser characteristics are deteriorated by thermal stress, and the yield is lowered due to destruction of the laser itself. It was.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a semiconductor laser device capable of improving yield and maintaining good laser characteristics.

  The semiconductor laser device of the present invention is provided in at least a part of the heat radiating member, the semiconductor laser element provided in one region of the heat radiating member, and the other region of the heat radiating member, and has a smaller linear expansion coefficient than the heat radiating member. And a stiffening portion made of a material.

  In the semiconductor laser device of the present invention, the stiffening portion having a smaller linear expansion coefficient than that of the heat dissipation member is provided in the region of the heat dissipation member that does not face the semiconductor laser element, so that the heat dissipation member generated due to the temperature change is provided. Expansion and contraction are alleviated. Therefore, the thermal stress applied from the heat dissipation member to the semiconductor laser element is reduced. In addition, since the semiconductor laser element is provided on the heat radiating member without interposing a stiffening portion, heat conduction from the semiconductor laser element to the heat radiating member is not hindered by the stiffening portion.

  According to the semiconductor laser device of the present invention, the heat dissipation member, the semiconductor laser element provided in one region of the heat dissipation member, and the linear expansion than the heat dissipation member are provided in at least a part of the other region of the heat dissipation member. Since the stiffening portion made of a material having a small coefficient is provided, thermal stress applied from the heat radiation member to the semiconductor laser element is reduced without hindering heat conduction from the semiconductor laser element to the heat radiation member. Therefore, it is possible to improve the yield and maintain good laser characteristics.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view showing a schematic configuration of a semiconductor laser device 1 according to an embodiment of the present invention. The semiconductor laser device 1 includes a semiconductor laser array 11, a stiffening portion 12, an insulating layer 13, and an electrode member 14 on a heat sink 10. On the heat sink 10, the semiconductor laser array 11 and the stiffening portion 12 are provided in different regions.

  The heat sink 10 enhances the heat exhaust effect of the semiconductor laser array 10 and is a material having thermal conductivity, for example, a single material such as copper (Cu), aluminum (Al), tungsten (W), molybdenum (Mo), A composite material such as these alloys, for example, a copper tungsten alloy (Cu—W), a copper molybdenum alloy (Cu—Mo), aluminum nitride (AlN), silicon carbide (SiC), or the like is used. However, it is preferable that it is comprised with the copper simple substance and the alloy containing copper from a heat conductive viewpoint. The thickness of the heat sink 10 is, for example, 3.0 mm to 10.0 mm. Note that the surface of the heat sink 10 (the surface on which the semiconductor laser array 10 is provided) is covered with a thin film (not shown) made of, for example, gold (Au) or the like in order to increase electrical conductivity with respect to the semiconductor laser array 11. ing.

  The semiconductor laser array 11 is provided on the heat sink 10 via the first bonding layer 10A. The semiconductor laser array 11 is a semiconductor laser element in which a plurality of light emitting regions are arranged in an array, and is configured to be electrically connected to the electrode member 14. The semiconductor laser array 11 has a width in the major axis direction of, for example, 10 mm, a resonator length of, for example, 200 μm to 1.5 mm, and a thickness of, for example, 100 μm. In the following description, the major axis direction of the semiconductor laser array 11 is simply referred to as the major axis direction.

  In this semiconductor laser array 11, a semiconductor layer including an active layer is formed on a substrate made of, for example, gallium arsenide (GaAs). The semiconductor layer is formed by stacking, for example, a lower clad layer, an active layer, an upper clad layer, a current injection layer, and the like, and is made of, for example, an AlGaInP-based compound semiconductor. The AlGaInP-based compound semiconductor here is a quaternary semiconductor including at least one of aluminum (Al) and gallium (Ga) and at least one of indium (In) and phosphorus (P). Examples thereof include AlGaInP mixed crystals, GaInP mixed crystals, and AlInP mixed crystals. These contain an n-type impurity such as silicon (Si) or selenium (Se), or a p-type impurity such as magnesium (Mg), zinc (Zn), or carbon (C) as necessary. With such a configuration, red light having an oscillation wavelength of, for example, 630 μm to 690 μm is emitted. Note that one of the surfaces perpendicular to the pair of end surfaces of the semiconductor laser array 11 is a light emitting surface. A p-side electrode or an n-side electrode is formed on the front and back of the semiconductor laser array 11.

  The stiffening portion 12 is provided on the heat sink 10 via the second bonding layer 12A. The stiffening portion 12 is made of a material having a smaller linear expansion coefficient than the heat sink 10, and is preferably made of a material having a smaller linear expansion coefficient than the heat sink 10 and the GaAs substrate of the semiconductor laser array 11. Here, Table 1 shows linear expansion coefficients of materials that can be assumed as materials of the heat sink 10 and the stiffening portion 12. The material constituting the stiffening portion 12 is determined by the constituent material of the heat sink 10. For example, when copper is used as the heat sink 10, diamond (C), tungsten, aluminum nitride, silicon carbide, chromium Platinum, magnesium oxide, antimony, iron, cobalt, nickel, bismuth, and the like can be used.

  Further, the stiffening portion 12 is preferably provided with a width in the major axis direction larger than the width in the major axis direction of the semiconductor laser array 11. More preferably, it is provided so as to be equal to the width of the heat sink 10 in the major axis direction. For example, it is formed so as to surround the region where the semiconductor laser array 11 is formed, and has side surfaces parallel to the three side surfaces excluding the light emitting surface of the semiconductor laser array 11. The thickness (volume) of the stiffening portion 12 is optimized by the linear expansion coefficient α0 of the entire system described later.

  The first bonding layer 11A and the second bonding layer 12A are made of, for example, a bonding metal such as solder. In addition, the melting point of the first bonding layer 11A is preferably lower than the melting point of the second bonding layer. For example, the first bonding layer 11A is made of an alloy containing silver and tin, and the second bonding layer 12A is made of an alloy containing gold and tin.

  The insulating layer 13 is provided, for example, between the stiffening portion 12 and an electrode member 14 described later, and is for ensuring electrical insulation between the stiffening portion 12 and the electrode member 14. The insulating layer 13 is made of an insulating material such as glass epoxy resin, and has a thickness of 0.5 mm to 1.0 mm, for example.

  The electrode member 14 is made of, for example, copper coated with gold or the like, and has a thickness of, for example, 1.0 mm to 3.0 mm. One end of the electrode member 14 is electrically connected to the semiconductor laser array 11 via the wire bonding 140, and the other end is connected to a single power source (not shown).

In such a configuration, the linear expansion coefficient of the material forming the heat sink 10 is α1 (× 10 ⁻⁶ / ° C.), the linear expansion coefficient of the material forming the stiffening portion 12 is α2 (× 10 ⁻⁶ / ° C.), The volume of the heat sink 10 is V1, the volume of the stiffening portion 12 is V2, and the linear expansion coefficient of a combined body (hereinafter simply referred to as a system) composed of the heat sink 10, the semiconductor laser array 11, and the stiffening portion 12 is α0 (× 10 ⁻⁶ / ° C.), the linear expansion coefficient α0 can be obtained by the following equation (1).
α0 = (V1 · α1 + V2 · α2) / (V1 + V2) (1)

Moreover, it is preferable that the linear expansion coefficient α0 obtained as described above satisfies the following formula (2).
α0 ≦ 9.4 (2)

  The semiconductor laser device 1 having the above configuration can be manufactured, for example, as follows.

First, the semiconductor laser array 11 is formed. For example, a compound semiconductor layer is formed on a substrate made of GaAs, for example, by MOCVD (Metal Organic Chemical Vapor Deposition) or MBE (Molecular Beam Epitaxy). At this time, for example, trimethylaluminum (TMA), trimethylgallium (TMG), trimethylindium (TMIn), and phosphine (PH ₃ ) are used as raw materials for the AlGaInP-based compound semiconductor as described above. For example, hydrogen selenide (H ₂ Se) is used, and dimethyl zinc (DMZ) is used as the acceptor impurity raw material, for example. Subsequently, electrodes are respectively formed on the surface of the formed compound semiconductor layer and the back surface of the GaAs substrate by vapor deposition, sputtering, or the like. After that, the semiconductor laser array 11 is formed by providing a reflecting mirror film (not shown) on the pair of end faces in the axial direction.

  Next, as shown in FIG. 3 (A), a heat sink 10 made of the above-described material is prepared, and, for example, by using a vacuum vapor deposition method or a plating method, for example, tin and 11A of 1st joining layers are formed by laminating | stacking silver in order. At this time, in a region other than the region where the first bonding layer 11A is formed, a mask is provided so that these layers are not deposited.

  On the other hand, as shown in FIG. 3B, a stiffening portion 12 made of the above-described material or the like is prepared, and, for example, gold and gold are deposited on the entire surface of the stiffening portion 12 by, for example, vacuum deposition or plating. The second bonding layer 12A is formed by sequentially laminating tin.

  Subsequently, the semiconductor laser array 11 is aligned with the first bonding layer 11A formed on the heat sink 10, and the stiffening portion 12 is aligned so that the side on which the second bonding layer 12A is formed faces the heat sink 12A. By doing so, each is placed on the heat sink 10.

  Subsequently, as shown in FIG. 4, the heat sink 10 on which the semiconductor laser array 11 and the stiffening portion 12 are mounted is subjected to a heat treatment to melt the first bonding layer 11 </ b> A and the second bonding layer 12 </ b> A. After that, the semiconductor laser array 11 and the stiffening portion 12 are bonded to the heat sink 10 by cooling them again and solidifying the first bonding layer 11A and the second bonding layer 12A. Finally, the insulating layer 13 and the electrode member 14 are sequentially formed on the stiffening portion 12 to complete the semiconductor laser device 1 shown in FIG.

  Here, an example in which the stiffening portion 12 and the semiconductor laser array 11 are joined by a single heat treatment has been described, but only the stiffening portion 12 is positioned on the heat sink 10 via the second joining layer 12A. After the heat treatment, the semiconductor laser array 11 may be aligned on the heat sink 10 and bonded again by the heat treatment. Further, the case where the first bonding layer 11A is formed on the heat sink 10 and the second bonding layer 12A is formed on the stiffening portion 12 has been described. The second bonding layer 12A may be formed in the planned installation area of the bonding layer 11A and the stiffening portion 12, and the semiconductor laser array 11 and the stiffening portion 12 may be placed thereon.

  Next, the operation and effect of the semiconductor laser device 1 of the present embodiment will be described.

  In the semiconductor laser device 1, the stiffening portion 12 having a linear expansion coefficient smaller than that of the heat sink 10 is provided in a region different from the region where the semiconductor laser array 11 of the heat sink 10 is provided. Thus, the expansion and contraction of the heat sink 10 that occur are alleviated. Therefore, the thermal stress applied from the heat sink 10 to the semiconductor laser array 11 is reduced when the semiconductor laser array 11 is bonded or operated at a high temperature. Further, since the semiconductor laser array 11 is provided with respect to the heat sink 10 without the stiffening portion 12 interposed, heat conduction from the semiconductor laser array 11 to the heat sink 10 is hindered by the provision of the stiffening portion 12. It will never be done. Further, since the semiconductor laser array 11 and the stiffening portion 12 are provided in the same plane on the heat sink 10, the thermal stress applied from the heat sink 10 to the semiconductor laser array 11 is effectively reduced.

Further, in the system composed of the heat sink 10, the semiconductor laser array 11, and the stiffening portion 12, the linear expansion coefficient after bonding, that is, the linear expansion coefficient α0 of the entire system is the linear expansion coefficient of each material before bonding. The volume ratio can be converted. However, since the volume of the semiconductor laser array 11 is generally about 1/100 or less of the heat sink 10, the semiconductor laser array 11 can be excluded from the system when calculating the linear expansion coefficient α0. Therefore, the linear expansion coefficient α1 (× 10 ⁻⁶ / ° C.) of the heat sink 10, the linear expansion coefficient of the stiffening portion 12 is α2 (× 10 ⁻⁶ / ° C.), the volume of the heat sink 10 is V 1, and the volume of the stiffening portion 12. the when the V2, the linear expansion coefficient of the entire system α0 (× 10 ^-6 / ℃) can be obtained by the following equation (1).
α0 = (V1 · α1 + V2 · α2) / (V1 + V2) (1)

Here, as shown in FIG. 5, a simulation was performed in the case where the semiconductor laser array 11 was joined on the heat sink 10 without providing the stiffening portion 12 (joining similar to the conventional art). At this time, copper was used as the heat sink 10 and the width in the major axis direction was 20 mm, the width in the depth direction was 15 mm, and the thickness was 5 mm. Further, for the semiconductor laser array 11, the width in the major axis direction was 10 mm, the width in the depth direction was 1 mm, and the thickness was 0.5 mm. As the first bonding layer, a solder containing gold and tin was used. The linear expansion coefficient of copper was 16.8 × 10 ⁻⁶ / ° C., and the linear expansion coefficient of the semiconductor laser array 11 was 5.9 × 10 ⁻⁶ / ° C., which is the linear expansion coefficient of GaAs.

First, heating is performed from 25 ° C. to 280 ° C. in order to melt the solder of the first bonding layer 11A. At this time, the expansion coefficient of copper of the heat sink 10 is 16.8 × (280−25) = 4284 × 10 ⁻⁶ m. That is, the portion having a width of 10 mm in the major axis direction of the region where the laser is provided becomes 10.04284 mm due to expansion. Similarly, when the width at which the semiconductor laser array 11 expands is obtained, 5.9 × (280−25) = 1504.5 × 10 ⁻⁶ m. That is, it becomes 10.05505 mm.

  Thereafter, when the temperature is lowered from 280 ° C. in order to harden the solder of the first bonding layer 11A, the heat sink 10 and the semiconductor laser array 11 are bonded by the first bonding layer 11A. When the temperature reaches 25 ° C., the length by which the combined body of the heat sink 10 and the semiconductor laser array 11 shrinks is expected to be 10.04284-10.01505 = 0.02779 mm. That is, the length of the semiconductor laser array 11 after bonding is approximately 10.000−0.02779 = 9.97221 mm. The measured values were 9.9632 mm (0.0368 mm shrinkage), 9.9688 mm (0.0312 mm shrinkage), and 9.9664 mm (0.0326 mm shrinkage).

  As described above, when the semiconductor laser array 11 is bonded onto the heat sink 10 without providing the stiffening portion 12, stress is applied to the semiconductor laser array 11 due to the difference in linear expansion coefficient between the heat sink 10 and the semiconductor laser array 11. (Particularly, compressive stress during cooling after heating) is applied, and this causes a phenomenon that the semiconductor laser array 11 contracts and the oscillation wavelength is shortened. This shortening of the wavelength is closely related to the rate of change (shrinkage rate) of the width in the major axis direction of the semiconductor laser array 11 as shown in FIG. For example, in the conventional configuration in which the stiffening portion is not provided, the change rate of the major axis width of the semiconductor laser array 11 is about 0.28%, and it can be seen that the wavelength is shortened to about 6.7 nm. In addition, the symbol of-(minus) is attached as the wavelength change in the figure indicates that the wavelength is shortened.

  When the wavelength is shortened as described above, there is a risk that the laser characteristics such as the light emission efficiency are deteriorated. For this reason, it is preferable that the major axis width change rate of the semiconductor laser array 11 is 0.24% or less, which is, for example, 6 nm or less.

Therefore, when the linear expansion coefficient is obtained such that the rate of change is 0.24% when the temperature is lowered from 280 ° C. to 25 ° C., for example, it is about 9.4 × 10 ⁻⁶ / ° C. Therefore, it is preferable that the linear expansion coefficient α0 of the entire system satisfies the following expression (2).
α0 ≦ 9.4 (2)

  Further, from the equation (1), the linear expansion coefficient α0 of the entire system can be set to a desired value by adjusting the material and volume (for example, thickness) of the heat sink 10 and the stiffening portion 12. In other words, as shown in FIG. 7, the linear expansion coefficient α0 is determined by the difference between the linear expansion coefficient α1 of the heat sink 10 and the linear expansion coefficient α2 of the stiffening portion 12 and the ratio of the respective volumes V1 and V2. Is done.

For example, aluminum nitride (linear expansion coefficient: 4.5 × 10 ⁻⁶ / ° C.) is used as the stiffening portion 12, and the volume V1 of the heat sink 10 is 750 mm ³ (width in the long axis direction: 10 mm, depth: 15 mm, thickness) : 5 mm), and the desired linear expansion coefficient α0 is, for example, 9.0 × 10 ⁻⁶ / ° C., the volume V2 of the stiffening portion 12 is found to be about 1300 mm ³ from Equation (1). In addition, when the width in the major axis direction of the stiffening portion 12 at this time is set to 10 mm equal to the heat sink 10 and the depth is set to 13 mm, the thickness may be set to about 10 mm.

Similarly, considering that the linear expansion coefficient α 0 is matched with the linear expansion coefficient of the semiconductor laser array 11, for example, the linear expansion coefficient of GaAs, the volume V 2 of the stiffening portion 12 is calculated from the expression (1). About 589.3 mm ³ . Therefore, in this case, it is understood that the thickness may be set to 44.9 mm. As described above, when the linear expansion coefficient α0 is equal to or smaller than the linear expansion coefficient of the semiconductor laser array 11, the thermal stress applied to the semiconductor laser array 11 is further reduced.

  Further, when the stiffening portion 12 is made of a material having a linear expansion coefficient smaller than that of the semiconductor laser array 11 such as GaAs, a material having a relatively large linear expansion coefficient such as copper is used for the heat sink 10. Even in such a case, the linear expansion coefficient α0 can be brought close to the linear expansion coefficient of the semiconductor laser array 11 by adjusting the volume of the stiffening portion 12 according to the equation (1). Therefore, the difference in linear expansion coefficient between the semiconductor laser array 11 and the entire system can be further reduced, and the thermal stress applied to the semiconductor laser array 11 is more effectively reduced.

  Further, when the melting point of the first bonding layer 11A is lower than the melting point of the second bonding layer, the semiconductor laser array 11 and the stiffening portion 12 are placed on the heat sink 10 and bonded by heat treatment. Due to the temperature drop after heating, the heat sink 10 and the stiffening portion 12 are first bonded together by the second bonding layer 12A, and then the heat sink 10 and the semiconductor laser array 11 are bonded by the first bonding layer 11A. Normally, heat shrinkage occurs in the heat sink when the temperature is lowered, which causes a great thermal stress on the semiconductor laser. In the present embodiment, before the semiconductor laser array 11 is bonded to the heat sink 10, the heat sink 10 is bonded to the stiffening portion 12, thereby preventing the heat shrinkage of the heat sink 10. Therefore, the thermal stress applied to the semiconductor laser array 11 is more effectively reduced.

  Further, in the longitudinal direction, the width of the stiffening portion 12 is equal to or larger than the width of the semiconductor laser array 11, preferably equal to the width of the heat sink 10, so that the longitudinal direction of the semiconductor laser array 11 is increased. The entire surface is less susceptible to the thermal contraction or expansion of the heat sink 10 that occurs when the semiconductor laser array 11 is joined or operated. Therefore, the thermal stress applied to the semiconductor laser array 11 is more effectively reduced.

  As described above, the stiffening portion 12 having a smaller linear expansion coefficient than the heat sink 10 is provided in a region different from the region where the semiconductor laser array 11 is provided on the heat sink 10. The thermal stress applied from the heat sink 10 to the semiconductor laser array 11 is reduced at the time of bonding to the heat sink 10 or at a high temperature operation. Further, since the semiconductor laser array 11 is provided with respect to the heat sink 10 without interposing the stiffening portion 12, the provision of the stiffening portion 12 prevents heat conduction from the semiconductor laser array 11 to the heat sink 10. There is nothing. Therefore, it is possible to improve the yield and maintain good laser characteristics.

  Next, a modification of the semiconductor laser device 1 of the present embodiment will be described.

(Modification 1)
FIG. 8 is a perspective view illustrating a schematic configuration of the semiconductor laser apparatus 2 according to the first modification. The semiconductor laser device 2 has the same configuration as the semiconductor laser device 1 except for the stiffening portion 22. Therefore, the same components as those of the semiconductor laser device 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  In the semiconductor laser device 2, the stiffening portion 22 is provided via the second bonding layer 12A in a region different from the region where the semiconductor laser array 11 is provided on the heat sink 10. The stiffening portion 22 is made of an insulating material having a smaller linear expansion coefficient than the heat sink 10. As a material constituting the stiffening portion 22, for example, a material containing at least one of silicon (Si), boron (B), carbon (C), and nitrogen (N) can be used.

  As described above, since the stiffening portion 12 is made of an insulating material, it is not necessary to newly provide an insulating layer for ensuring electrical insulation between the heat sink 10 and the electrode member 14. On the other hand, since the semiconductor laser array 11 is provided on the heat sink 10 without the stiffening portion 22 interposed, the stiffening portion 22 prevents the semiconductor laser array 10 and the heat sink 11 from conducting heat conduction and electrical conduction. It will never be done. Accordingly, it is possible to improve the yield and maintain good laser characteristics with a simple configuration.

(Modification 2)
FIG. 9 is a perspective view illustrating a schematic configuration of the semiconductor laser apparatus 3 according to the second modification. FIG. 10 is a plan view of the stiffening portion 32 of the semiconductor laser device 3. The semiconductor laser device 3 has the same configuration as the semiconductor laser device 1 except for the stiffening portion 32 and the second bonding layer 32A. Therefore, the same components as those of the semiconductor laser device 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  In the semiconductor laser device 3, a stiffening portion 32 is provided via a second bonding layer 32A in a region different from the region where the semiconductor laser array 11 is provided on the heat sink 10. The stiffening portion 32 is provided so as to surround the semiconductor laser array 11, and two corner portions of the three side surfaces respectively opposed to the three side surfaces excluding the light emitting surface of the semiconductor laser array 11 have curved portions 320. ing. The second bonding layer 32 </ b> A is formed along the shape of the bottom surface of the stiffening portion 32.

  Here, as shown in FIG. 10, in the stiffening portion 32, a first region 32-1 that does not face the short axis direction of the semiconductor laser array 11 and a second region 32 that faces the short axis direction of the semiconductor laser array 11. -2, since the difference between the widths 32-1a and 32-2a in the major axis direction is large, a large difference occurs in the stress received from the heat sink 10. Accordingly, the two corners of the three side surfaces of the stiffening portion 32 facing the semiconductor laser array 11 have the curved portions 320, so that the vicinity of the boundary between the first region 32-1 and the second region 32-2. , The stress received from the heat sink 10 is dispersed, and the generation of cracks can be suppressed.

(Modification 3)
FIG. 11 is a perspective view illustrating a schematic configuration of the semiconductor laser apparatus 4 according to the third modification. The semiconductor laser device 4 has the same configuration as the semiconductor laser device 1 except that another stiffening portion 42 is further provided. Therefore, the same components as those of the semiconductor laser device 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  In the semiconductor laser device 4, a stiffening portion 42 is provided on the side surface of the heat sink 10. The stiffening portion 42 is made of a material having a larger linear expansion coefficient than that of the heat sink 10, for example, a copper alloy such as brass (copper and zinc alloy), an aluminum simple substance, or a silicon simple substance.

  As described above, the stiffening portion 42 made of a material having a larger linear expansion coefficient than that of the heat sink 10 is provided on the side surface side of the heat sink 10, so that the stiffening portion 42 expands or contracts due to a temperature change. Thus, expansion and contraction in the thickness direction of the heat sink 10 are promoted. Therefore, expansion and contraction in the in-plane direction of the heat sink 10 are suppressed. Therefore, the thermal stress applied from the heat sink 10 to the semiconductor laser array 11 is more effectively reduced.

  Although the present invention has been described with reference to the embodiment and the modifications, the present invention is not limited to the above-described embodiment and the like, and various modifications can be made.

  For example, in the above-described embodiment and the like, the shape of the stiffening portion provided on the heat sink 10 has been described as an example of a rectangular shape or an arch shape, but the region other than the region where the semiconductor laser array 11 is provided is described. The stiffening part should just be formed in at least one part, and the shape is not specifically limited.

  In the above-described embodiment and the like, the configuration in which the semiconductor laser array 11 and the stiffening portion 12 are provided in the same plane on the heat sink 10 has been described. However, the present invention is not limited to this. A configuration in which a stiffening portion is provided on the surface opposite to the side where the semiconductor laser array 11 is formed may be employed.

  In the above embodiments, the present invention has been described by taking an AlGaInP-based compound semiconductor laser as an example. However, other compound semiconductor lasers, for example, red semiconductor lasers such as AlInP-based and GaInAsP-based, GaInN-based and AlGaInN-based, etc. The present invention is also applicable to II-VI group semiconductor lasers such as gallium nitride semiconductor lasers and ZnCdMgSSeTe. The present invention is also applicable to semiconductor lasers whose oscillation wavelength is not always in the visible range, such as AlGaAs, InGaAs, InP, and GaInAsNP.

1 is a cross-sectional view illustrating a schematic configuration of a semiconductor laser device according to an embodiment of the present invention. FIG. 2 is a front view and a plan view illustrating a schematic configuration of the semiconductor laser device illustrated in FIG. 1. FIG. 2 is a diagram illustrating a manufacturing method of the semiconductor laser device illustrated in FIG. 1 in order of steps. FIG. 4 is a diagram illustrating a process that follows the process illustrated in FIG. 3. It is a perspective view of the semiconductor laser apparatus used in the simulation which calculates the linear expansion coefficient of the whole system. It is a characteristic view showing the oscillation wavelength with respect to the change rate of a semiconductor laser array. It is a figure showing the relationship between the linear expansion coefficient of a heat sink and a stiffening part, and a volume. 11 is a perspective view illustrating a schematic configuration of a semiconductor laser device according to Modification 1. FIG. 10 is a perspective view illustrating a schematic configuration of a semiconductor laser device according to Modification 2. FIG. FIG. 10 is a plan view illustrating a schematic configuration of the semiconductor laser device illustrated in FIG. 9. 10 is a perspective view illustrating a schematic configuration of a semiconductor laser device according to Modification 3. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1, 2, 3, 4 ... Semiconductor laser apparatus, 10 ... Heat sink, 11 ... Semiconductor laser array, 12, 22, 32, 42 ... Stiffening part, 11A ... 1st joining layer, 12A 2nd joining layer, 13 ... Insulation Layer, 14 ... electrode member.

Claims (16)

A heat dissipating member;
A semiconductor laser element provided in one region of the heat dissipation member;
A semiconductor laser device comprising: a stiffening portion provided in at least a part of another region of the heat dissipation member and made of a material having a smaller linear expansion coefficient than the heat dissipation member. The semiconductor laser device according to claim 1, wherein the stiffening portion is made of a material having a smaller linear expansion coefficient than the semiconductor laser element. The linear expansion coefficient of the combined body composed of the heat radiating member, the stiffening portion, and the semiconductor laser element is α0 (× 10 ⁻⁶ / ° C.), and the linear expansion coefficient of the material constituting the heat radiating member is α1 (× 10 ^{− 6} / ° C.), when the coefficient of linear expansion of the material constituting the stiffening portion is α2 (× 10 ⁻⁶ / ° C.), the volume of the heat dissipation member is V1, and the volume of the stiffening portion is V2.
The semiconductor laser device according to claim 1, wherein the linear expansion coefficient α0 satisfies the following expression (1).
α0 = (V1 · α1 + V2 · α2) / (V1 + V2) (1) The semiconductor laser device according to claim 3, wherein the linear expansion coefficient α0 satisfies the following expression (2).
α0 ≦ 9.4 (2) A first bonding layer between the heat dissipation member and the semiconductor laser element, and a second bonding layer between the heat dissipation member and the stiffening portion,
The semiconductor laser device according to claim 1, wherein a melting point of a material forming the first bonding layer is lower than a melting point of a material forming the second bonding layer. The first bonding layer is made of a material containing gold (Au) and tin (Sn), and the second bonding layer is made of a material containing tin and silver (Ag). The semiconductor laser device according to claim 5. The semiconductor laser device according to claim 1, wherein the semiconductor laser element is a semiconductor laser array in which a plurality of light emitting regions are arranged in parallel. The semiconductor laser device according to claim 7, wherein the stiffening portion has a width equal to or larger than a width of the semiconductor laser array in a longitudinal direction of the semiconductor laser array. . The semiconductor laser device according to claim 7, wherein the stiffening portion has a width equal to that of the heat dissipation member in a longitudinal direction of the semiconductor laser array. The semiconductor laser device according to claim 1, wherein the semiconductor laser element and the stiffening portion are provided in the same plane of the heat dissipation member. The semiconductor laser device according to claim 10, wherein the stiffening portion is provided so as to surround a region where the semiconductor laser array is formed. The semiconductor laser array is rectangular,
The semiconductor laser device according to claim 11, wherein the stiffening part has three side surfaces parallel to each of three side surfaces excluding the light emitting surface of the semiconductor laser array. The semiconductor laser device according to claim 12, wherein the stiffening portion has a bent portion at a corner portion of the three side surfaces. Comprising another stiffening portion made of a material having a larger linear expansion coefficient than the heat dissipation member,
The semiconductor laser device according to claim 1, wherein the other stiffening portion is provided adjacent to a surface perpendicular to a surface of the heat dissipation member on which the semiconductor laser element is provided. The stiffening portion includes copper (Cu), aluminum (Al), nickel (Ni), tungsten (W), molybdenum (Mo), iron (Fe), chromium (Cr), cobalt (Co) and bismuth (Bi). The semiconductor laser device according to claim 1, comprising at least one of the above. The stiffening portion is made of a material containing silicon oxide (SiO ₂ ), diamond (C), aluminum nitride (AlN), silicon carbide (SiC), or magnesium oxide (MgO). 1. The semiconductor laser device according to 1.

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