JP2017028044A - Semiconductor laser device and method for manufacturing semiconductor laser device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor laser device and a method for manufacturing semiconductor laser device, capable of simplifying a joining process and also improving heat dissipation properties from a semiconductor laser element to a heat sink.SOLUTION: A semiconductor laser device 1 includes: a heat sink 2; a heat conductive insulation substrate 3 provided on one face side of the heat sink 2 and having a conductive pattern 8 formed on a surface thereof; a laminate structure 7 provided on one face side of the insulation substrate 3 and including laser units 6 laminated in an in-plane direction of the insulation substrate 3, each laser unit including a semiconductor laser bar 4 mounted on a sub mount 5; a first solder layer 10A for joining laser units 6, 6 to each other and joining the other end side of the sub mount 5 and the conductive pattern 8; and a second solder layer 10B for joining the heat sink 2 and the insulating substrate 3. The first solder layer 10A comprises solder having a higher melting point than the solder constituting the second solder layer 10B, and extends at least from one end side to the other end side of the sub mount 5.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a semiconductor laser device and a method for manufacturing a semiconductor device.

  As a conventional semiconductor laser device, for example, there is a semiconductor laser device described in Patent Document 1. In this semiconductor laser device, a laminated structure in which a semiconductor laser element and a semi-insulating member electrically parallel to the semiconductor laser element are sandwiched between submounts made of an insulating member or a metal member is disposed on an insulating substrate. Yes. This semiconductor laser device has a back surface cooling structure in which cooling is performed on the opposite side of the laser light oscillation direction, and heat generated in the semiconductor laser element during laser oscillation is transmitted through an insulating substrate or metal member through an insulating substrate ( And a heat sink connected to the insulating substrate).

  For example, in the semiconductor laser device described in Patent Document 2, a laminated structure in which both electrode surfaces of a semiconductor laser element are sandwiched between a pair of heat sinks is disposed on an insulator ceramic substrate. This patent document 2 also discloses an example in which a laminated structure is configured by sandwiching a semiconductor laser element mounted on a submount made of a conductor or an insulator between a pair of heat sinks.

Japanese Patent Laid-Open No. 11-121859 JP-A-5-37089

  In Patent Document 1 described above, details of bonding between the stacked structure and the insulating substrate and bonding between the semiconductor laser element and the submount in the stacked structure are not mentioned. However, in the semiconductor laser device as described above, these junctions are important. For example, if the position of the end of the submount with respect to the semiconductor laser element and the insulating substrate becomes uneven due to manufacturing tolerances of the submount, the contact area between the semiconductor laser element and the submount becomes insufficient. It is conceivable that a connection failure occurs between the mount and the insulating substrate. If such a problem occurs, the heat dissipation from the semiconductor laser element to the heat sink may be reduced.

  In Patent Document 2 described above, the submount and the insulator ceramic substrate are not connected, and there is room for improvement in heat dissipation from the semiconductor laser to the insulator ceramic substrate. Moreover, in the structure of patent document 2, many processes are required for joining of each component. An increase in the number of bonding steps causes an increase in the manufacturing cost of the semiconductor laser device.

  The present invention has been made to solve the above problems, and provides a semiconductor laser device and a method for manufacturing the semiconductor laser device that can simplify the joining process and improve the heat dissipation from the semiconductor laser element to the heat sink. For the purpose.

  In order to solve the above problems, a semiconductor laser device according to one aspect of the present invention includes a heat sink, a heat conductive insulating substrate provided on one surface side of the heat sink, and having a conductor pattern formed on the surface, and one surface side of the insulating substrate. A laminated structure in which laser units each having a semiconductor laser element mounted on a submount are stacked in the in-plane direction of the insulating substrate, the laser units, the other end of the submount, and a conductor on the insulating substrate A first solder layer that joins the pattern; and a second solder layer that joins the heat sink and the insulating substrate. The first solder layer has a higher melting point than the solder constituting the second solder layer. And extends at least from one end side of the submount to the other end side.

  In this semiconductor laser device, the first solder layer is used for joining the laser units and the other end of the submount to the conductor pattern on the insulating substrate, and the second solder layer is used for joining the heat sink and the insulating substrate. Is used. The first solder layer is composed of solder having a melting point higher than that of the solder constituting the second solder layer. With this configuration, in this semiconductor laser device, since the laser units can be bonded together and the other end side of the submount and the conductor pattern on the insulating substrate can be simultaneously bonded, the bonding process can be simplified. In the semiconductor laser device, the first solder layer extends from at least one end side of the submount to the other end side. Therefore, even if the end position of the submount with respect to the semiconductor laser element and the insulating substrate becomes uneven due to the manufacturing tolerance of the submount, the first solder layer is attached to the end face on one end side of the submount at the time of bonding. Further, the contact area between the semiconductor laser element and the submount and the thermal connection between the submount and the insulating substrate can be ensured by wrapping around the end face on the other end side. Therefore, the heat dissipation from the semiconductor laser element to the heat sink can be improved.

  The laser unit may be configured by sandwiching a semiconductor laser element between a pair of submounts. In this case, the bonding of the laminated structure to the insulating substrate can be made stronger. Further, the heat dissipation path from the semiconductor laser element to the heat sink is expanded by increasing the volume of the submount in the laminated structure. Thereby, the heat dissipation from the semiconductor laser element to the heat sink can be further improved.

  The stacked structure may further include an intermediate mount stacked between the laser units, and the first solder layer may be provided so as to cover the surface of the intermediate mount. In this case, the heat dissipation path from the semiconductor laser element to the heat sink is expanded by interposing the intermediate mount. Thereby, the heat dissipation from the semiconductor laser element to the heat sink can be further improved.

  The intermediate mount may be made of copper tungsten. Thereby, the thermal conductivity and electrical conductivity of the intermediate mount can be secured satisfactorily. Further, the difference in thermal expansion coefficient with the semiconductor laser element can be suppressed, and distortion and the like can be suppressed from occurring in the laminated structure.

  Further, the solder constituting the first solder layer may be gold tin solder, and the solder constituting the second solder layer may be indium solder. In this case, a sufficient difference in melting point between the solder constituting the first solder layer and the solder constituting the second solder layer can be secured. Therefore, it is possible to prevent the heat at the time of joining the heat sink and the insulating substrate by the second solder layer from affecting the first solder layer.

  The submount may be made of copper tungsten. Thereby, the thermal conductivity and electrical conductivity of the submount can be ensured satisfactorily. Further, the difference in thermal expansion coefficient with the semiconductor laser element can be suppressed, and distortion and the like can be suppressed from occurring in the laminated structure.

  The insulating substrate may be made of aluminum nitride. Thereby, the electrical insulation and heat dissipation of the insulating substrate can be ensured satisfactorily. Further, the difference in thermal expansion coefficient with the semiconductor laser element can be suppressed, and distortion and the like can be suppressed from occurring in the laminated structure.

  In addition, a method of manufacturing a semiconductor laser device according to one aspect of the present invention includes a heat sink, a heat conductive insulating substrate provided on one surface side of the heat sink and having a conductor pattern formed on the surface, and provided on one surface side of the insulating substrate. A stacked structure in which laser units each having a semiconductor laser element mounted on a submount are stacked in the in-plane direction of the insulating substrate, the laser units, the other end of the submount, and a conductor pattern on the insulating substrate; A method for manufacturing a semiconductor laser device, comprising: a first solder layer that joins the second solder layer; and a second solder layer that joins the heat sink and the insulating substrate. The method is higher than the solder constituting the second solder layer. A first solder layer is disposed between the laser units so as to extend at least from one end side to the other end side of the submount using a melting point solder, and the first solder layer A first bonding step of simultaneously bonding the laser units and the other end of the submount and the conductor pattern on the insulating substrate to obtain a bonded body of the insulating substrate and the laminated structure, and the insulating substrate and heat sink of the bonded body And a second bonding step in which a second solder layer is disposed between the insulating substrate and the heat sink by the second solder layer to obtain a semiconductor laser device.

  In this method of manufacturing a semiconductor laser device, the first solder layer is used for bonding the laser units and the other end of the submount to the conductor pattern on the insulating substrate, and the second solder layer is bonded to the heat sink and the insulating substrate. Solder layer is used. Further, as the first solder layer, solder having a melting point higher than that of the solder constituting the second solder layer is used. With this configuration, in this method of manufacturing a semiconductor laser device, since the laser units can be bonded together and the other end of the submount and the conductor pattern on the insulating substrate can be simultaneously bonded, the bonding process can be simplified. In this method of manufacturing a semiconductor laser device, the first solder layer is disposed so as to extend at least from one end side to the other end side of the submount. Therefore, even if the end position of the submount with respect to the semiconductor laser element and the insulating substrate becomes uneven due to the manufacturing tolerance of the submount, the first solder layer is attached to the end face on one end side of the submount at the time of bonding. Further, the contact area between the semiconductor laser element and the submount and the thermal connection between the submount and the insulating substrate can be ensured by wrapping around the end face on the other end side. Therefore, the heat dissipation from the semiconductor laser element to the heat sink can be improved.

  Further, as the laser unit, a laser unit configured by sandwiching a semiconductor laser element between a pair of submounts may be used. In this case, the bonding of the laminated structure to the insulating substrate can be made stronger. Further, the heat dissipation path from the semiconductor laser element to the heat sink is expanded by increasing the volume of the submount in the laminated structure. Thereby, the heat dissipation from the semiconductor laser element to the heat sink can be further improved.

  In the first bonding step, the first solder layer may be formed between the laser units by vapor deposition or plating. Thereby, control of the film thickness of the first solder layer is facilitated, and assembly of the laminated structure can be stably performed in a short time.

  In the first bonding step, a first solder layer may be formed between the laser units using a solder sheet. Thereby, arrangement | positioning of a 1st solder layer becomes easy and the assembly of a laminated structure can be implemented stably in a short time.

  In the first bonding step, an intermediate submount whose surface is covered by the first solder layer may be disposed between the laser units. Thereby, arrangement | positioning of a 1st solder layer becomes easy and the assembly of a laminated structure can be implemented stably in a short time.

  According to the present invention, the joining process can be simplified and the heat dissipation from the semiconductor laser element to the heat sink can be improved.

1 is a schematic side view showing a configuration of a semiconductor laser device according to a first embodiment of the present invention. FIG. 2 is an enlarged side view of a main part of the semiconductor laser device shown in FIG. 1. 2A and 2B are schematic views showing a manufacturing process of the semiconductor laser device shown in FIG. 1, wherein FIG. 1A shows a configuration of a laser unit, FIG. 1B shows a first joining process, and FIG. 2C shows a second joining process. It is a figure which shows the effect of a 1st solder layer, (a) is a principal part expanded side view of the one end side of a submount, (b) is a principal part enlarged side view of the other end side of a submount. It is the schematic which shows the modification of 1st Embodiment, (a) shows the modification of a laser unit, (b) shows the modification of a 1st joining process. It is a principal part expanded side view which shows the further modification of the semiconductor laser apparatus which concerns on 1st Embodiment. It is a principal part expanded side view which shows the structure of the semiconductor laser apparatus which concerns on 2nd Embodiment of this invention. FIG. 8 is a schematic view showing a manufacturing process of the semiconductor laser device shown in FIG. 7. (A) is a structure of a laser unit, (b) shows a 1st joining process, (c) shows a 2nd joining process. It is the schematic which shows the modification of 2nd Embodiment, (a) shows the modification of a laser unit, (b) shows the modification of a 1st joining process. It is a principal part enlarged side view which shows the further modification of the semiconductor laser apparatus which concerns on 2nd Embodiment.

Hereinafter, preferred embodiments of a semiconductor laser device and a method for manufacturing a semiconductor device according to one aspect of the present invention will be described in detail with reference to the drawings.
[First Embodiment]

  FIG. 1 is a schematic side view showing the configuration of the semiconductor laser device according to the first embodiment of the present invention. As shown in the figure, a semiconductor laser device 1 includes a laminated structure 7 in which a heat sink 2, an insulating substrate 3, a laser unit 6 including a semiconductor laser bar (semiconductor laser element) 4 and a submount 5 are laminated. And is configured. The semiconductor laser device 1 has a back surface cooling structure in which cooling is performed on the opposite side of the laser beam oscillation direction, and heat generated in the semiconductor laser bar 4 during laser oscillation is transmitted through the submount 5 and the insulating substrate 3 as a heat sink. Heat is dissipated to the 2 side. The heat sink 2 is formed in a thick plate shape with a material having high thermal conductivity such as copper (Cu). A flow path such as cooling water may be formed inside the heat sink.

  The insulating substrate 3 is formed in a plate shape from a material having heat conductivity and electrical insulation, such as aluminum nitride (AlN). Other forming materials of the insulating substrate 3 include silicon carbide (SiC), diamond and the like. On one surface side of the insulating substrate 3, for example, a conductor pattern 8 formed by vapor deposition using a predetermined mask is provided. The conductor pattern 8 is composed of, for example, four metal layers of titanium (Ti) / copper (Cu) / nickel (Ni) / gold (Au) stacked in order from the surface side of the insulating substrate 3.

  On the other surface side of the insulating substrate 3, similarly to the conductor pattern 8, a metal layer 9 composed of four metal layers of titanium (Ti) / copper (Cu) / nickel (Ni) / gold (Au) is formed. It is formed by vapor deposition. The thickness of the metal layer 9 is approximately the same as that of the conductor pattern 8, and warpage of the insulating substrate 3 due to the formation of the conductor pattern 8 is suppressed.

  The other surface side of the insulating substrate 3 is bonded to one surface side of the heat sink 2 over the entire surface. For joining the insulating substrate 3 and the heat sink 2, the second solder layer 10B is used. As the solder constituting the second solder layer 10B, indium (In) solder, for example, is used from the viewpoint of lead-free. The melting point of indium solder is approximately 156 ° C. The solder constituting the second solder layer 10B may be SnAgCu solder. The melting point of SnAgCu solder is approximately 217 ° C to 220 ° C.

  The laminated structure 7 is configured by laminating a plurality of (in this embodiment, five) laser units 6, and is arranged on the insulating substrate 3 so that the laminating direction of the laser units 6 coincides with the in-plane direction of the insulating substrate 3. Is arranged. The laser unit 6 includes a submount 5 and a semiconductor laser bar 4, respectively. The submount 5 is formed in a plate shape from a material having thermal conductivity and electrical conductivity such as copper tungsten (CuW). Other constituent materials of the submount 5 include aluminum nitride (AlN), silicon carbide (SiC), tungsten (W), copper molybdenum (MoCu) composite material, copper diamond composite material, and the like. Two plating layers of nickel (Ni) and gold (Au) may be formed on the surface of the submount 5.

  The semiconductor laser bar 4 has a plate shape, for example. As shown in FIG. 2, the front end surface of the semiconductor laser bar 4 is an emission end surface 4a having a plurality of light emitting regions. One surface 4b of the semiconductor laser bar 4 is joined to the one surface 5b side of the submount 5 so that the emission end surface 4a and the one end surface 5a of the submount 5 are flush with each other.

  The semiconductor laser bar 4 has a substrate made of a compound semiconductor, and an active layer is located at a position corresponding to the light emitting region, and a clad layer is located on both sides of the active layer. Examples of the substrate material include gallium arsenide (GaAs), gallium nitride (GaN), aluminum gallium arsenide (AlGaAs), (gallium phosphide) GaP, aluminum gallium nitride (AlGaN), indium phosphide (InP), and the like. It is done. In this embodiment, for example, the main component of the substrate is gallium arsenide (GaAs), the active layer further contains indium (In), and the clad layer further contains aluminum (Al).

  In the laminated structure 7, as shown in FIG. 2, the laser units 6 and 6 adjacent to each other in the lamination direction are laminated so that the submounts 5 and the semiconductor laser bars 4 are alternately arranged, and the first solder layer 10A are joined together. The first solder layer 10A is composed of solder having a melting point higher than that of the solder constituting the second solder layer 10B. An example of such solder is gold-tin solder. The melting point of gold-tin solder is 280 ° C.

  The first solder layer 10A extends at least from one end side to the other end side of the submount 5 on the other surface (the surface opposite to the arrangement surface of the semiconductor laser bar 4) 5c side of the submount 5. The other surface 4c of the semiconductor laser bar 4 in the laser unit 6 and the other surface 5c of the submount 5 of the other laser unit 6 are joined. A part of the first solder layer 10A goes around to the other end surface 5d side of the submount 5 and joins the other end surface 5d of the submount 5 and the conductor pattern 8 on the insulating substrate 3 (FIG. 4B). reference). In addition, a part of the first solder layer 10A also wraps around the one end face 5a side of the submount 5 (see FIG. 4A).

  Although not shown, for example, the same solder as that constituting the first solder layer 10A is used for joining the semiconductor laser bar 4 and the submount 5. That is, in this embodiment, the entire surface 4b of the semiconductor laser bar 4 is joined to the surface 5b of the submount 5 using gold tin solder.

  When the semiconductor laser device 1 is driven, the conductor pattern 8 connected to the submount 5 on one end side in the stacking direction of the stacked structure 7 and the submount 5 on the other end side in the stacking direction of the stacked structure 7 are connected. A driving voltage is applied between the conductive pattern 8 and the conductor pattern 8. As a result, a drive current is supplied to all the semiconductor laser bars 4 included in the multilayer structure 7, and laser light oscillates from the plurality of light emitting regions of the emission end face 4a. Heat generated in the semiconductor laser bar 4 during laser oscillation is transmitted from the adjacent submount 5 to the insulating substrate 3 and is radiated to the heat sink 2 side.

An example of the dimensions of each component of the semiconductor laser device 1 is as follows.
Semiconductor laser bar 4: Width 10 mm, depth 1 mm to 4 mm, thickness 100 μm to 150 μm
Submount 5: width 10 mm to 12 mm, depth 1 mm to 5 mm, thickness 0.1 mm to 1 mm (nickel plating layer: thickness 2 μm to 3 μm, gold plating layer: thickness 0.1 μm to 0.5 μm)
Insulating substrate 3: thickness 0.2 mm to 0.8 mm (conductor pattern 8 and metal layer 9: titanium 0.5 μm / copper 70 to 150 μm / nickel 1 μm / gold 0.5 μm)
First solder layer 10A: thickness 1 μm to 20 μm
Second solder layer 10B: thickness 1 μm to 30 μm

  Then, the manufacturing method of the semiconductor laser apparatus 1 mentioned above is demonstrated.

  When manufacturing the semiconductor laser device 1, first, as shown in FIG. 3A, laser units 6 are prepared according to the number of stacked layers. In the formation of the laser unit 6, the entire surface 4b of the semiconductor laser bar 4 is bonded to the surface 5b of the submount 5 using gold tin solder. Further, the first solder layer 10A made of gold-tin solder is formed on the other surface 5c of the submount 5 by vapor deposition or plating so as to extend at least from one end side to the other end side of the submount 5.

  Next, as shown in FIG. 3B, the laser units 6 are stacked so that the submounts 5 and the semiconductor laser bars 4 are alternately arranged to form a stacked structure 7. In addition, the insulating substrate 3 is prepared, and the insulating substrate 3 is arranged with respect to the laminated structure 7. At this time, a positioning jig (not shown) is used for positioning the laser units 6 and 6 and positioning the laminated structure 7 and the insulating substrate 3. The positioning jig positions the laser units 6 and 6 so that the positions of the emission end face 4a of the semiconductor laser bar 4 and the one end face 5a of the submount 5 are aligned with each other, and the other end face of the submount 5 in each laser unit 6 The laminated structure 7 and the insulating substrate 3 are positioned so that 5d is in close contact with the conductor pattern 8 of the insulating substrate 3, respectively.

  Next, in a state of being positioned by the positioning jig, the laminated structure 7 and the insulating substrate 3 are put into a reflow furnace, and the first solder layer 10A is heated to a temperature equal to or higher than the melting point (280 ° C.) of the gold-tin solder. As a result, the laser units 6 and 6 and the other end of the submount 5 and the conductor pattern 8 on the insulating substrate 3 are simultaneously bonded to obtain a bonded body W1 of the insulating substrate 3 and the laminated structure 7 (first). 1 joining step). In the first bonding step, the gold-tin solder for bonding the semiconductor laser bar 4 and the submount 5 is heated again. However, the gold-tin solder undergoes a certain alloying process at the first bonding. Since the melting point is increased, the bonding between the semiconductor laser bar 4 and the submount 5 is not removed in the first bonding step.

  After the joined body W1 is formed, the second solder layer 10B is disposed between the insulating substrate 3 and the heat sink 2 of the joined body W1. The second solder layer 10B may be formed on one surface side of the heat sink 2 or the other surface side (on the metal layer 9) by vapor deposition, for example. Then, the insulating substrate 3 of the joined body W1 and the heat sink 2 are brought into close contact with each other by using a positioning jig, and the second solder layer 10B has a melting point (156 ° C.) higher than that of indium solder and gold tin solder. To a temperature below the melting point of (280 ° C.). Thus, as shown in FIG. 3C, the insulating substrate 3 and the heat sink 2 are bonded to obtain the semiconductor laser device 1 (second bonding step).

  As described above, in the semiconductor laser device 1, the first solder layer 10A is used for joining the laser units 6 and 6 and the other end side of the submount 5 and the conductor pattern 8 on the insulating substrate 3, A second solder layer 10 </ b> B is used for joining the heat sink 2 and the insulating substrate 3. The first solder layer 10A is composed of solder having a melting point higher than that of the solder constituting the second solder layer 10B.

  With this configuration, in the semiconductor laser device 1, since the laser units 6 and 6 can be joined together and the other end of the submount 5 and the conductor pattern 8 on the insulating substrate 3 can be joined simultaneously, the joining process is simplified. it can. In a typical comparative example, for example, a joining process of joining laser units using silver (Ag) paste, a joining process of joining an insulating substrate and a heat sink using indium solder, and a laminated structure are joined to the insulating substrate. 3 joining processes of the joining process to perform are provided. On the other hand, in this embodiment, the 1st joining process which joins laser units 6 and 6 and submount 5 and insulating substrate 3 simultaneously, and the 2nd joining process which joins joined object W1 and heat sink 2 are joined. Thus, the semiconductor laser device 1 can be obtained.

  In the semiconductor laser device 1, the first solder layer 10 </ b> A extends at least from one end side of the submount 5 to the other end side. As a result, even if the end positions of the submount 5 with respect to the semiconductor laser bar 4 and the insulating substrate 3 become uneven when the laser units 6 are stacked due to manufacturing tolerances of the submount 5, the semiconductor laser bar 4 can heat sink. 2 can be ensured and improved.

  For example, as shown in FIG. 4A, due to the manufacturing tolerance of the submount 5, one end surface 5a of the submount 5 is one step lower than the emission end surface 4a of the semiconductor laser bar 4 of the adjacent laser unit 6. Even in the case of being closed, the step is filled by part of the first solder layer 10 </ b> A wrapping toward the one end face 5 a side of the submount 5 in the first bonding step. Thereby, a contact area between the semiconductor laser bar 4 and the submount 5 is ensured.

  For example, as shown in FIG. 4B, due to the manufacturing tolerance of the submount 5, the other end surface 5d of the submount 5 is one step lower than the other end surface 5d of the submount 5 of the adjacent laser unit 6. Even in such a case, a part of the first solder layer 10A wraps around the other end face 5d side of the submount 5 in the first bonding step, so that the step is filled. Thereby, it can suppress that the connection defect of the other end surface 5d of the submount 5 and the conductor pattern 8 arises, and the thermal connection between the submount 5 and the insulated substrate 3 is ensured.

  In the semiconductor laser device 1, the solder constituting the first solder layer 10A is gold-tin solder, and the solder constituting the second solder layer 10B is indium solder. As a result, a sufficient difference in melting point between the solder constituting the first solder layer 10A and the solder constituting the second solder layer 10B can be secured. Therefore, it is possible to prevent the heat when the heat sink 2 and the insulating substrate 3 are joined by the second solder layer 10B from affecting the first solder layer 10A.

  In the semiconductor laser device 1, the submount 5 is made of copper tungsten. Thereby, the thermal conductivity and electrical conductivity of the submount 5 can be ensured satisfactorily. In addition, the difference in thermal expansion coefficient between the semiconductor laser bar 4 and the laminated structure 7 can be prevented from being distorted. Further, the insulating substrate 3 is made of aluminum nitride. Thereby, the electrical insulation and heat dissipation of the insulating substrate 3 can be ensured satisfactorily. In addition, the difference in thermal expansion coefficient between the semiconductor laser bar 4 and the laminated structure 7 can be prevented from being distorted.

  In the present embodiment, the first solder layer 10A is formed on the other surface 5c of the submount 5 in the first bonding step. However, as shown in FIG. A first solder layer 10A may be formed on the surface 5c and the other surface 4c of the semiconductor laser bar 4, respectively. In this case, it is possible to easily cause the first solder layer 10A to wrap around the one end surface 5a of the submount 5 in the first bonding step.

  Further, the formation of the first solder layer 10A is not limited to vapor deposition or plating. For example, as shown in FIG. 5B, the first solder layer 10 </ b> A may be formed by arranging the solder sheet 11 between the laser units 6 and 6. In this case, the arrangement of the first solder layer 10A is facilitated, and the laminated structure 7 can be stably assembled in a short time.

Further, as shown in FIG. 6, in the first bonding step, the intermediate mount 12 whose surface is covered with the first solder layer 10 </ b> A may be disposed between the laser units 6 and 6. The intermediate mount 12 is formed in a plate shape from a material having thermal conductivity and electrical conductivity such as copper tungsten (CuW). The dimension of the intermediate mount 12 may be equal to the dimension of the submount 5, and the dimension including the first solder layer 10 </ b> A covering the intermediate mount 12 may be equal to the dimension of the submount 5. By using such an intermediate mount 12, the arrangement of the first solder layer 10A is facilitated, and the laminated structure 7 can be assembled stably in a short time.
[Second Embodiment]

  FIG. 7 is an enlarged side view of the main part showing the configuration of the semiconductor laser device according to the second embodiment of the present invention.

  As shown in the figure, the semiconductor laser device 21 according to the second embodiment differs from the first embodiment in that the laser unit 6 is configured by sandwiching the semiconductor laser bar 4 between a pair of submounts 5 and 5. Yes. More specifically, in the semiconductor laser device 21, the first solder layer 10 </ b> A is disposed between one submount 5 and the other submount 5 in the adjacent laser units 6 and 6. The first solder layer 10A extends at least from one end side to the other end side of the submount 5, and joins the other surface 5c of one submount 5 and the other surface 5c of the other submount 5. ing.

  When manufacturing the semiconductor laser device 21, first, as shown in FIG. 8A, the laser unit 6 is prepared according to the number of stacked layers. In forming the laser unit 6, for example, gold-tin solder is used for joining the semiconductor laser bar 4 and the submounts 5, 5 as in the first embodiment. Further, on the other surface 5c of any one of the submounts 5, a first solder layer 10A made of gold-tin solder is formed by vapor deposition or plating so as to extend from at least one end side of the submount 5 to the other end side. To do.

  Next, as shown in FIG. 8B, the laser unit 6 is laminated so as to sandwich the first solder layer 10A, thereby forming a laminated structure 7. In addition, the insulating substrate 3 is prepared, and the insulating substrate 3 is arranged with respect to the laminated structure 7. A positioning jig similar to that in the first embodiment is used for positioning the laser units 6 and 6 and positioning the laminated structure 7 and the insulating substrate 3. The positioning jig positions the laser units 6 and 6 so that the positions of the emission end surface 4a of the semiconductor laser bar 4 and the end surfaces 5a of the submounts 5 and 5 are aligned with each other. The laminated structure 7 and the insulating substrate 3 are positioned so that the other end surface 5 d of the substrate 5 is in close contact with the conductor pattern 8 of the insulating substrate 3.

  Next, in a state of being positioned by the positioning jig, the laminated structure 7 and the insulating substrate 3 are put into a reflow furnace, and the first solder layer 10A is heated to a temperature equal to or higher than the melting point (280 ° C.) of the gold-tin solder. As a result, the laser units 6 and 6 and the other ends of the submounts 5 and 5 and the conductor pattern 8 on the insulating substrate 3 are simultaneously bonded to obtain a bonded body W2 of the insulating substrate 3 and the laminated structure 7. (First joining step).

  After the joined body W2 is formed, the second solder layer 10B is disposed between the insulating substrate 3 and the heat sink 2 of the joined body W2. Then, the insulating substrate 3 of the bonded body W2 and the heat sink 2 are brought into close contact with each other by using a positioning jig, and the second solder layer 10B has a melting point (156 ° C.) higher than that of indium solder and gold tin solder. To a temperature below the melting point of (280 ° C.). Thereby, as shown in FIG. 8C, the insulating substrate 3 and the heat sink 2 are bonded to obtain the semiconductor laser device 21 (second bonding step).

  Also in such a semiconductor laser device 21, since the laser units 6, 6 can be bonded together and the other end side of the submounts 5, 5 and the conductor pattern 8 on the insulating substrate 3 can be simultaneously bonded, the bonding process can be performed. It can be simplified. Further, even if the end positions of the submount 5 with respect to the semiconductor laser bar 4 and the insulating substrate 3 become uneven due to manufacturing tolerances of the submount 5, the first solder layer 10A is attached to the submount 5 at the time of bonding. The heat dissipation from the semiconductor laser bar 4 to the heat sink 2 can be improved by going around the one end surface 5a and the other end surface 5d.

  Further, in the semiconductor laser device 21, the semiconductor laser bar 4 is sandwiched between the pair of submounts 5 and 5 to constitute the laser unit 6, so that the bonding of the laminated structure 7 to the insulating substrate 3 is made stronger. Can do. Further, the heat dissipation path from the semiconductor laser bar 4 to the heat sink 2 is expanded by increasing the volume of the submount 5 in the laminated structure 7. Thereby, the heat dissipation from the semiconductor laser bar 4 to the heat sink 2 can be further improved.

  In the present embodiment, the first solder layer 10A is formed on the other surface 5c of any one of the submounts 5 in the first bonding step. However, as shown in FIG. The first solder layer 10 </ b> A may be formed on each of the other surfaces 5 c of the submounts 5 and 5. In this case, it is possible to easily cause the first solder layer 10A to wrap around the one end surface 5a of the submount 5 in the first bonding step.

  Further, as shown in FIG. 9B, instead of vapor deposition or plating, the solder sheet 22 may be disposed between the laser units 6 and 6 to form the first solder layer 10A. In this case, the arrangement of the first solder layer 10A is facilitated, and the laminated structure 7 can be stably assembled in a short time. Furthermore, as shown in FIG. 10, in the first bonding step, the intermediate mount 12 whose surface is covered with the first solder layer 10 </ b> A may be disposed between the laser units 6 and 6. By using such an intermediate mount 12, the arrangement of the first solder layer 10A is facilitated, and the laminated structure 7 can be assembled stably in a short time.

  DESCRIPTION OF SYMBOLS 1,21 ... Semiconductor laser apparatus, 2 ... Heat sink, 3 ... Insulating substrate, 4 ... Semiconductor laser bar (semiconductor laser element), 5 ... Submount, 6 ... Laser unit, 7 ... Laminated structure, 8 ... Conductor pattern, 10A ... 1st solder layer, 10B ... 2nd solder layer, 11, 22 ... solder sheet, 12 ... intermediate mount, W1, W2 ... joined body.

Claims (12)

A heat sink,
A heat-conductive insulating substrate provided on one surface side of the heat sink and having a conductor pattern formed on the surface;
A laminated structure formed by laminating a laser unit provided on one surface side of the insulating substrate and having a semiconductor laser element mounted on a submount in an in-plane direction of the insulating substrate;
A first solder layer for bonding the laser units, and the other end side of the submount and the conductor pattern on the insulating substrate;
A second solder layer for joining the heat sink and the insulating substrate;
The first solder layer is composed of solder having a melting point higher than that of the solder constituting the second solder layer, and extends at least from the one end side to the other end side of the submount. .   The semiconductor laser device according to claim 1, wherein the laser unit is configured by sandwiching the semiconductor laser element between a pair of the submounts. The stacked structure further includes an intermediate mount stacked between the laser units,
The semiconductor laser device according to claim 1, wherein the first solder layer is provided so as to cover a surface of the intermediate mount.   4. The semiconductor laser device according to claim 3, wherein the intermediate mount is made of copper tungsten.   5. The semiconductor laser device according to claim 1, wherein the solder constituting the first solder layer is gold-tin solder, and the solder constituting the second solder layer is indium solder. 6.   The semiconductor laser device according to claim 1, wherein the submount is made of copper tungsten.   The semiconductor laser device according to claim 1, wherein the insulating substrate is made of aluminum nitride. A heat sink,
A heat-conductive insulating substrate provided on one surface side of the heat sink and having a conductor pattern formed on the surface;
A laminated structure formed by laminating a laser unit provided on one surface side of the insulating substrate and having a semiconductor laser element mounted on a submount in an in-plane direction of the insulating substrate;
A first solder layer for bonding the laser units, and the other end side of the submount and the conductor pattern on the insulating substrate;
A method of manufacturing a semiconductor laser device comprising: a second solder layer that joins the heat sink and the insulating substrate;
A solder having a melting point higher than that of the solder constituting the second solder layer is used, and the first solder layer is disposed between the laser units so as to extend at least from the one end side to the other end side of the submount. And arranging the laser unit and the other end side of the submount and the conductor pattern on the insulating substrate simultaneously by the first solder layer, and bonding the insulating substrate and the laminated structure. A first joining step for obtaining a body;
The second solder layer is disposed between the insulating substrate and the heat sink of the bonded body, and the semiconductor substrate is obtained by bonding the insulating substrate and the heat sink by the second solder layer. A method for manufacturing a semiconductor laser device.   9. The method of manufacturing a semiconductor laser device according to claim 8, wherein a laser unit configured by sandwiching the semiconductor laser element between a pair of submounts is used as the laser unit.   10. The method of manufacturing a semiconductor laser device according to claim 8, wherein in the first bonding step, the first solder layer is formed between the laser units by vapor deposition or plating.   10. The method of manufacturing a semiconductor laser device according to claim 8, wherein in the first bonding step, the first solder layer is formed between the laser units using a solder sheet.   10. The method of manufacturing a semiconductor laser device according to claim 8, wherein an intermediate submount whose surface is covered with the first solder layer is disposed between the laser units in the first bonding step.

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