JP4925118B2 - Manufacturing method of semiconductor laser device - Google Patents

Description

  The present invention relates to a semiconductor laser device and a method for manufacturing the semiconductor laser device, and more specifically, a semiconductor laser device in which a ridge waveguide semiconductor laser element having a double channel type is mounted junction-down, and manufacturing of the semiconductor laser device Regarding the method.

  In recent years, the information society has permeated, and from the personal computer to the video, these data have been recorded on the optical disk. The amount of information is steadily increasing, and the capacity of discs is increasing from CD (Compact Disc) to DVD (Digital Versatile Disc) and BD (Blue-ray Disc). A semiconductor laser element used as a light source achieves a large capacity by using a short wavelength light source such as infrared (780 nm band) to red (650 nm band) and blue-violet (405 nm band). Furthermore, the recording speed has been increased, and the demand for higher output of the semiconductor laser element is increasing. High output semiconductor laser devices are required to have strict specifications such as high efficiency, low operating voltage (Vop), temperature characteristics, high mode stability at high output, and the like.

  When current is injected into such a semiconductor laser element, light energy is generated by recombination of injected electrons and holes in the active region of the semiconductor laser element. If all of the current injected by recombination is converted into light energy, heat is not generated, but in reality, electric energy is converted into light energy (light emission) and heat energy (heat generation). Specifically, due to the spread of current, heat is generated by a recombination current that does not contribute to light emission. Further, heat is generated by the oscillation light of the semiconductor laser element being absorbed around the active region. Also, Joule heat is generated by the resistance component of the semiconductor laser element. Due to such factors, the semiconductor laser element generates heat.

  When the optical output is increased by increasing the injection current of the semiconductor laser element, the amount of heat generation increases as the optical output (optical energy) increases. In particular, the Joule heat generated by the element resistance increases as the operating voltage increases. Therefore, when the semiconductor laser device is driven at a high output, it is necessary to reduce these heat generations and to dissipate heat efficiently. Therefore, the heat radiation of the semiconductor laser element is performed by releasing the heat by mounting the semiconductor laser element on, for example, a copper stem via the submount.

  In the semiconductor laser element, since the heat source is in the vicinity of the active layer, the heat dissipation is improved as the active layer is as close as possible to the stem. The semiconductor laser element has a thickness of about 100 μm, but the active layer is usually located about 1 μm from the surface, and the heat dissipation greatly varies depending on the mounting direction.

  When mounted with the active layer side up (junction up), a good beam shape can be obtained, and the active layer side is processed and an electrode pattern is formed. There are advantages such as ease of taking. On the other hand, when the active layer side is disposed below (junction down), that is, mounted on the stem side, there is an advantage that heat dissipation is improved. For this reason, when the semiconductor laser device is used at a higher output, it is desired to mount it at junction-down in order to improve heat dissipation due to increased heat generation of the semiconductor laser device.

  In order to obtain higher output, a ridge waveguide semiconductor laser that confines light and confines current by forming a ridge stripe shape on the active layer, such as the layers from the cladding layer to the contact layer. Devices are widely used. Since the ridge waveguide type semiconductor laser can be manufactured by one crystal growth, the cost can be reduced. However, the width of the ridge stripe is as narrow as several μm to several tens of μm while the width of the semiconductor laser element is several hundred μm. For this reason, when this ridge waveguide type semiconductor laser device is mounted by junction-down, the mount stress may concentrate on the ridge stripe and the ridge may be destroyed. Therefore, if dummy ridges having the same height as these are provided on both sides of the ridge stripe (hereinafter also referred to as a double channel), the semiconductor laser element can be supported by the dummy ridge, so that the concentration of stress on the ridge stripe is reduced. And the destruction of the ridge stripe can be prevented.

Examples of mounting such a double channel type semiconductor laser device by junction down include JP-A-2005-223070 (Patent Document 1) and JP-A-2003-86877 (Patent Document 2). Patent Document 1 discloses a semiconductor laser device in which no cavity is formed between a semiconductor laser element and a submount. Patent Document 2 discloses a semiconductor laser device in which a cavity is formed between a groove between a ridge and a dummy ridge and a submount in a semiconductor laser element, and no cavity is formed in other portions. ing.
Japanese Patent Laying-Open No. 2005-223070 JP 2003-86877 A

  However, although the double channel semiconductor laser elements of Patent Documents 1 and 2 are mounted by junction down, the increase in operating voltage cannot be sufficiently suppressed, and there is still room for improvement.

  SUMMARY OF THE INVENTION Therefore, the present invention solves the above-described problems and suppresses a rise in operating voltage even when mounted by junction down, thereby enabling a semiconductor laser device capable of high-output and high-reliability operation and a method for manufacturing the semiconductor laser device. The purpose is to provide.

  As a result of diligent research, the present inventor has mounted a ridge waveguide type semiconductor laser device of a double channel type in a junction-down manner as disclosed in Patent Documents 1 and 2 above, and a case where the junction-up type is mounted. It was found that the operating voltage increased and the reliability decreased. In addition, the present inventor has found that an increase in operating voltage of a semiconductor laser device mounted with junction down causes damage to the semiconductor laser element due to an impact applied when the semiconductor laser element is wire-bonded. It was found to be due to.

  Therefore, the semiconductor laser device of the present invention includes a semiconductor laser element, a mounted base, and a wire. The semiconductor laser element includes a substrate, an active layer formed on the substrate, another layer formed on the active layer, and an electrode formed on the other layer. A ridge portion and a dummy ridge portion extending in parallel with the ridge portion with the ridge portion interposed therebetween are formed on the surface opposite to the opposite side. The mounted base is electrically connected to other layers in the semiconductor laser element. The wire is electrically connected to the substrate of the semiconductor laser element. A cavity is formed between the electrode formed on the top surface of the ridge portion and the mount base, and at least a part of the electrode formed on the top surface of the ridge portion in the semiconductor laser element is exposed to the cavity. ing.

  The method for manufacturing a semiconductor laser device of the present invention includes a step of preparing, a step of fixing another layer and the mount base, and a step of electrically connecting the substrate and the wire. The preparing step includes a substrate, an active layer formed on the substrate, another layer formed on the active layer, and an electrode formed on the other layer. A semiconductor laser device is prepared in which a ridge portion and a dummy ridge portion extending in parallel with the ridge portion are formed on the opposite surface and the opposite surface. In the step of fixing the other layer and the mount base, the other layer in the semiconductor laser element and the mount base are fixed. In the step of electrically connecting the substrate and the wire, the substrate of the semiconductor laser element and the wire are electrically connected. In the step of fixing the other layer and the mounted base, a cavity is formed between the electrode formed on the top surface of the ridge portion and the mounted base, and the top surface of the ridge portion in the semiconductor laser device. Exposing at least a portion of the electrode formed thereon to the cavity.

  According to the semiconductor laser device and the manufacturing method of the semiconductor laser device of the present invention, in the step of fixing the other layer and the mount base, the top surface of the ridge portion of the semiconductor laser device is mounted at the junction down A cavity is formed between the formed electrode and the mount base, and at least a part of the electrode formed on the top surface of the ridge portion in the semiconductor laser element is exposed to the cavity. For this reason, the cavity can reduce the impact applied to the ridge portion during the process of electrically connecting the substrate and the wire, thereby reducing damage to the semiconductor laser element. Therefore, an increase in the operating voltage of the semiconductor laser device can be suppressed, efficiency is not degraded, and reliability can be improved. That is, a semiconductor laser device capable of high-output and high-reliability operation can be obtained by suppressing an increase in operating voltage even when mounted by junction down.

  Preferably, the semiconductor laser device further includes a metal film disposed between the dummy ridge portion and the mount base.

  Preferably, in the method of manufacturing the semiconductor laser device, the step of fixing the other layer and the mount base is a metal on at least one of the dummy ridge portion and the surface of the mount base facing the dummy ridge portion. The method includes a step of disposing a film and a step of fixing the dummy ridge portion and the mount base through the metal film.

  Thus, in the step of fixing the other layer and the mount base, a cavity can be easily provided between the ridge portion and the mount base by the metal film.

  Preferably, the semiconductor laser device further includes solder disposed between the dummy ridge portion and the mount base.

  Preferably, in the method of manufacturing the semiconductor laser device, the step of fixing the other layer and the mount base includes a step of placing solder so as to be in contact with the dummy ridge portion, and a step of fixing the dummy ridge portion and the target base via the solder. And a step of fixing the mount base.

  Preferably, in the method of manufacturing the semiconductor laser device, the step of fixing the other layer and the mount base includes a step of placing solder on the surface of the mount base facing the dummy ridge portion, And a step of fixing the dummy ridge portion and the mounted base.

  Thus, in the step of fixing the other layer and the mount base, a cavity can be easily provided between the ridge portion and the mount base by solder.

  Preferably, the semiconductor laser device manufacturing method further includes a step of filling the cavity with solder.

  Thus, the impact applied to the ridge portion by the cavity during the process of electrically connecting the substrate and the wire can be reduced, and the heat dissipation can be improved by the solder embedded in the cavity when the semiconductor laser device is used.

  Preferably, the semiconductor laser device further includes two or more kinds of solders having different melting points disposed between the dummy ridge portion and the mount base.

  Preferably, in the method of manufacturing the semiconductor laser device, the step of fixing the other layer and the mount base is performed on at least one of the dummy ridge portion and the mount base with two or more different melting points. The solder having a relatively low melting point is heated, and the solder having a relatively low melting point is melted while being heated to a temperature at which the solder having a relatively high melting point is not melted. Including a step of fixing the dummy ridge portion and the mount base, and a step of embedding the cavity through the solder having a relatively high melting point by heating to a temperature at which the solder having a relatively high melting point is melted. Is further provided.

  Thus, in the step of fixing the other layer and the mounted base, the other layer and the mounted base can be fixed by dissolving only half of the relatively low melting point. At that time, a cavity can be easily provided between the electrode formed on the ridge portion and the mounted base with a solder having a relatively high melting point. Also, by melting the solder with a relatively high melting point after the step of electrically connecting the substrate and the wire, the impact applied to the semiconductor laser element by the cavity during the step of electrically connecting the substrate and the wire is reduced. In addition, when the semiconductor laser device is used, heat dissipation can be improved by solder having a relatively high melting point.

  According to the semiconductor laser device and the manufacturing method of the semiconductor laser device of the present invention, a cavity is provided between the electrode formed on the ridge portion and the mount base when mounting at the junction down, Since the electrodes formed in the above are exposed in the cavity, a semiconductor laser device capable of high output and high reliability operation can be obtained by suppressing an increase in operating voltage even when mounted by junction down.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment 1)
FIG. 1 is a schematic perspective view showing a semiconductor laser device according to Embodiment 1 of the present invention. With reference to FIG. 1, a semiconductor laser device according to the first embodiment of the present invention will be described. As shown in FIG. 1, the semiconductor laser device 100a in the present embodiment includes a semiconductor laser element 117, a mounted base, and a wire 116a. The semiconductor laser element 117 includes a substrate 100, an active layer 104 formed on the substrate 100, another layer 117a formed on the active layer 104, and an electrode formed on the other layer 117a. Yes. On the surface of the other layer 117a opposite to the side facing the active layer 104, a ridge portion 117b and a dummy ridge portion 117c extending in parallel with the ridge portion 117b with the ridge portion 117b interposed therebetween are formed. A cavity 130 is formed between the electrode formed on the top surface of the ridge 117b and the mounted base, and the electrode formed on the top surface of the ridge 117b in the semiconductor laser element 117 is exposed to the cavity 130. is doing. As shown in FIG. 1, the semiconductor laser device 100a includes a semiconductor laser element arranged such that the substrate 100 is on the upper side (the side farther from the other layer 117a when viewed from the mounted base) with respect to the direction of gravity. This is a junction down structure in which 117 and the mount base are fixed.

  As shown in FIG. 1, the semiconductor laser device 100a in the present embodiment includes a semiconductor laser element 117, a stem 115, a submount 118, wires 116a and 116b, a metal film 111, lead wires 119a and 119b, It has.

  The semiconductor laser element 117 includes a substrate 100, an n-type buffer layer 101, an n-type cladding layer 102, an n-type guide layer 103, an active layer 104, a p-type evaporation prevention layer 105, and a p-type cladding layer 106. , A p-type contact layer 107, an insulating film 108, a p-type electrode layer 109, and an n-type electrode layer 110.

  The substrate 100 is made of a conductive material such as n-type GaN (gallium nitride), and has a thickness of 100 μm. N-type buffer layer 101 is provided in contact with substrate 100 and is made of, for example, n-type GaN and has a thickness of 0.2 μm. The n-type cladding layer 102 is provided in contact with the n-type buffer layer 101 and is made of, for example, AlGaN (aluminum gallium nitride) and has a thickness of 2 μm. The n-type guide layer 103 is provided in contact with the n-type cladding layer 102 and is made of, for example, GaN and has a thickness of 20 nm. The active layer 104 is provided in contact with the n-type guide layer 103, and has a multiple quantum well structure in which, for example, three InGaN (indium gallium nitride) well layers and three GaN barrier layers are stacked, and the thickness of the well layer is The thickness of the barrier layer is 4 nm and 4 nm.

  The other layer 117 a in this embodiment includes a p-type evaporation prevention layer 105, a p-type cladding layer 106, and a p-type contact layer 107. The p-type evaporation preventing layer 105 is provided in contact with the active layer 104 and is made of, for example, AlGaN and has a thickness of 20 nm. The p-type cladding layer 106 is provided in contact with the p-type evaporation prevention layer 105 and is made of, for example, AlGaN, and has a thickness of 0.55 μm. The p-type contact layer 107 is provided in contact with the p-type cladding layer 106 and is made of, for example, GaN and has a thickness of 0.1 μm.

The insulating film 108 is provided in contact with the p-type contact layer 107 in a region excluding the ridge portion 117b, and plays a role of injecting current only into the ridge portion 117b. The insulating film 108 is made of, for example, SiO ₂ (silicon oxide) and has a thickness of 0.2 μm. The p-type electrode layer 109 is provided in contact with the p-type contact layer 107 in the ridge portion 117b (the portion of the p-type electrode layer 109 formed on the top surface of the ridge portion 117b in FIG. 1 is the p-type electrode layer). 109a) and regions other than the ridge portion 117b (dummy ridge portion 117c and a groove formed between the dummy ridge portion 117c and the ridge portion 117b) are provided in contact with the insulating film 108, for example, Pd (palladium) and It is made of Au (gold), the thickness of Pd is 50 nm, and the thickness of Au is 0.2 μm. The n-type electrode layer 110 is provided in contact with the surface of the substrate 100 opposite to the surface on which the n-type buffer layer 101 is formed, and is made of, for example, Hf (hafnium), Pt (platinum), and Au. The thickness is 50 nm, the thickness of Pt is 100 nm, and the thickness of Au is 0.2 μm.

  The semiconductor laser element 117 has a structure in which a groove is formed over a part of the p-type contact layer 107 and the p-type cladding layer 106, that is, a double channel structure of a striped ridge portion 117b and a dummy ridge portion 117c. The ridge portion 117b is a portion having a substantially trapezoidal cross-sectional shape sandwiched between grooves. A p-type electrode layer 109a is provided in contact with the top surface of the ridge portion 117b, and an insulating film 108 is provided in contact with the side surface of the ridge portion 117b. The dummy ridge portion 117c is a portion extending in parallel with the ridge portion 117b via a groove. A laminated body of the insulating film 108 and the p-type electrode layer 109 is provided in contact with the insulating film 108 side in the dummy ridge portion 117c and the groove between the dummy ridge portion 117c and the ridge portion 117b.

  In this embodiment, a nitride semiconductor laser element is used as the semiconductor laser element 117. However, the present invention is not limited to this, and a red semiconductor laser element, an infrared semiconductor laser element, or the like may be used as the semiconductor laser element 117. Good. Further, the configuration of each layer of the semiconductor laser element 117 is not limited to the above-described layer.

  The metal film 111 is disposed between the dummy ridge portion 117c and the mounted base. The metal film 111 of the present embodiment includes a dummy ridge 117c and a groove formed between the dummy ridge 117c and the ridge 117b on the surface of the other layer 117a and the submount 118. It is formed through the insulating film 108 and the p-type electrode layer 109. For the metal film 111, for example, a plated conductive layer made of Au or the like can be used.

  As shown in FIG. 1, the thickness L of the metal film 111 protruding from the ridge portion 117b is preferably 0.5 μm or more and 5 μm or less from the viewpoint that the cavity 130 is easily held.

  The wire 116 a is electrically connected to the substrate 100 of the semiconductor laser element 117. In the present embodiment, the wire 116a electrically connects the substrate 100 and the lead wire 119a for extracting the electrode. For example, Au or the like can be used for the wire 116a.

  The wire 116b is electrically connected to the mounted base. The wire 116b in the present embodiment electrically connects the submount electrode layer 113b of the submount 118 and the lead wire 119b for extracting the electrode. For example, Au or the like can be used for the wire 116b.

  The mounted base includes a submount 118 and a stem 115 connected to the submount 118.

  The submount 118 is connected to another layer 117 a in the semiconductor laser element 117. The submount 118 includes a submount material 112, submount electrode layers 113a and 113b, and solder layers 114a and 114b. Submount material 112 is made of, for example, SiC (silicon carbide). The submount electrode layers 113a and 113b are formed on the front surface and the back surface of the submount material 112, and are formed by stacking, for example, Ti (titanium), Pt (platinum), and Au. The solder layers 114a and 114b are formed on the surfaces of the submount electrode layers 113a and 113b, and are made of, for example, AuSn (gold tin). The solder layer 114b is fixed to the dummy ridge portion 117c.

  The solder layer 114 a on the side not connected to the semiconductor laser element 117 in the submount 118 is connected to the stem 115. The stem 115 is made of, for example, Cu (copper).

  Next, with reference to FIGS. 1-7, the manufacturing method of the semiconductor laser apparatus in Embodiment 1 of this invention is demonstrated. FIG. 2 is a flowchart showing a method for manufacturing the semiconductor laser device according to the first embodiment of the present invention. FIG. 3 is a schematic diagram for explaining a preparation step in the first embodiment of the present invention. FIG. 4 is another schematic diagram for explaining the preparation step in the first embodiment of the present invention. FIG. 5 is a schematic diagram for explaining a process of fixing the dummy ridge portion and the mounted base in the first embodiment of the present invention. FIG. 6 is a schematic diagram showing a state after performing the step of fixing the dummy ridge portion and the mounted base in the first embodiment of the present invention. FIG. 7 is a schematic diagram for explaining a process of filling the cavity with solder in the first embodiment of the present invention.

  As shown in FIGS. 2 and 3, first, the substrate 100, the active layer 104 formed on the substrate 100, the other layer 117a formed on the active layer 104, and the other layer 117a are formed. On the surface of the other layer 117a opposite to the side facing the active layer 104, a ridge portion 117b and a dummy ridge portion 117c extending in parallel with the ridge portion 117b with the ridge portion 117b interposed therebetween are formed. The step (S10) of preparing the semiconductor laser device 117 is performed. In the step of preparing (S10), for example, the semiconductor laser element 117 described above is prepared.

  Specifically, as shown in FIG. 3, a substrate 100 made of a conductive material such as GaN is prepared. A multi-quantum structure in which an n-type buffer layer 101 made of GaN, an n-type cladding layer 102 made of AlGaN, an n-type guide layer 103 made of GaN, an InGaN well layer and a GaN guide layer are stacked on the substrate 100. The active layer 104, the p-type evaporation prevention layer 105 made of AlGaN, the p-type cladding layer 106 made of AlGaN, and the p-type contact layer 107 made of GaN are arranged in this order, for example, MOCVD (Metal Organic Chemical Vapor Deposition). It is formed by crystal growth by the (growth) method. Subsequently, for example, a mask layer is formed on the p-type contact layer 107 in the regions to be the ridge portion 117b and the dummy ridge portion 117c, and a groove is dug into the middle of the p-type contact layer 107 and the p-type cladding layer 106 by etching. When the mask layer is removed, the ridge portion 117b and the dummy ridge portion 117c can be formed, and a double channel structure can be obtained.

  Thereafter, a mask layer is formed on the ridge portion 117b, and the insulating film 108 is formed in a region other than the ridge portion 117b by, for example, a CVD (Chemical Vapor Deposition) method. After the mask layer is removed, the region including the ridge portion 117b and reaching the dummy ridge portion 117c (on the p-type contact layer 107, the groove in the ridge portion 117b, and the insulating film 108 in the dummy ridge portion 117c), for example, an evaporation method Thus, the p-type electrode layer 109 is formed.

  Thereafter, the back surface of the substrate 100 (the surface opposite to the surface on which the n-type buffer layer 101 is formed on the substrate 100) is polished to a thickness of, for example, 100 μm, and the n-type electrode layer 110 is formed on the back surface by, for example, vapor deposition. To do. Then, a reflection end face is formed by cleavage, an end face reflection film is formed on the end face, and finally, the semiconductor laser element 117 is manufactured by dividing into chips.

  In the preparation step (S10), the growth conditions and growth method of the semiconductor laser device 117 are not particularly limited to this, and other crystal growth methods such as MBE (Molecular Beam Epitaxy) method are employed. May be.

  Next, as shown in FIGS. 2 to 4, a step (S <b> 20) of fixing the other layer 117 a and the mount base in the semiconductor laser element 117 is performed. In this step (S20), a cavity 130 is formed between the electrode formed on the top surface of the ridge portion 117b and the mount base, and is formed on the top surface of the ridge portion 117b in the semiconductor laser element 117. Exposing the exposed electrode to the cavity 130.

  In the step (S20) of fixing the other layer 117a and the mount base in the present embodiment, a metal is formed on at least one of the dummy ridge portion 117c and the surface of the mount base facing the dummy ridge portion 117c. A step (S21) of disposing the film 111 and a step (S22) of fixing the dummy ridge 117c and the mount base via the metal film 111 are included.

  Specifically, as shown in FIG. 3, the submount electrode layer 113a, 113b is formed by preparing the submount material 112 and sequentially forming Ti, Pt and Au on both surfaces thereof by vapor deposition. Then, solder layers 114a and 114b are formed on the submount electrode layers 113a and 113b. Thereby, the submount 118 can be prepared. The solder layer 114b on the side facing the semiconductor laser element 117 of the submount 118 is preferably not formed on the entire surface of the submount material 112 but formed so that the submount electrode layer 113b is exposed at the end. .

  Subsequently, for example, a mask layer is formed on the ridge portion 117b, and as shown in FIG. 3, a metal film 111 is formed on the p-type electrode layer 109 in a region other than the ridge portion 117b by an electrolytic plating method. Further, for example, a mask layer is formed on a region facing the ridge 117b in the solder layer 114b of the submount 118, and as shown in FIG. 4, on the solder layer 114b in a region other than the region facing the ridge 117b. A metal film 111 is formed by electrolytic plating. Thereafter, when the mask layer is removed, as shown in FIGS. 3 and 4, at least one of the dummy ridge portion 117c and the surface of the mounted base (the submount 118 in this embodiment) facing the dummy ridge portion 117c. On the other hand, the step (S21) of disposing the metal film 111 on the other side can be performed.

  Note that the method for forming the metal film 111 is not particularly limited. For example, other vapor deposition methods or sputtering methods can be employed. However, since the thick metal film 111 can be formed relatively easily, it is preferably formed by an electroplating method. .

  Thereafter, the semiconductor laser element 117 and the submount 118 shown in FIGS. 3 and 4 are turned upside down, and as shown in FIG. 5, the solder layer 114b of the submount 118 and the other layer 117a in the semiconductor laser element 117. The semiconductor laser element 117 is placed on the submount 118 so that the surfaces thereof (the surface on which the ridge portion 117b is formed and the surface on which the dummy ridge portion 117c is formed) face each other.

  Further, as shown in FIG. 5, a stem 115 is prepared. Then, the submount 118 is placed on the stem 115 so that the solder layer 114a of the submount 118 and the stem 115 face each other. That is, the submount 118 is mounted on the stem 115, and the semiconductor laser element 117 is mounted thereon with the ridge portion 117b facing downward.

  In a state where the semiconductor laser element 117 shown in FIG. 5 is mounted on the stem 115 via the submount 118 (a state in which the semiconductor laser device 117 is mounted with junction down), the p-type metal film 111 is formed on the top surface of the ridge portion 117b. Since the electrode layer 109a is not disposed at a position facing the electrode layer 109a, the p-type electrode layer 109a formed on the top surface of the ridge 117b of the semiconductor laser element 117 and the mount base (in this embodiment, the submount 118) A cavity is formed between the two.

  In this state, when the temperature is raised to a temperature equal to or higher than the melting temperature of the solder layers 114a and 114b (for example, 310 ° C. in this embodiment), the solder layers 114a and 114b are melted as shown in FIG. The submount 118 and the semiconductor laser element 117 are integrated. Thereby, the step (S22) of fixing the dummy ridge 117c and the mount base (the submount 118 in the present embodiment) via the metal film 111 can be performed.

  In the step (S20) of fixing the other layer 117a and the mount base in the semiconductor laser element 117, the area between the semiconductor laser element 117 and the mount base, excluding the ridge 117b. Since the metal film 111 is formed so as to protrude, a cavity 130 is formed between the ridge 117b and the submount 118. When the temperature is raised in the fixing step (S22), the solder layers 114a and 114b melt and flow into the cavity 130, but the p-type electrode layer 109a formed on the top surface of the ridge 117b is exposed to the cavity 130. . From the viewpoint of easily holding the cavity 130, in the step (S21) of disposing the metal film 111, the thickness L (see FIG. 1) protruding from the ridge 117b in the metal film 111 is set to 0.5 μm or more and 5 μm or less. It is preferable to form the metal film 111.

  Next, as shown in FIGS. 1 and 2, a step (S30) of electrically connecting the substrate 100 of the semiconductor laser element 117 and the wire 116a is performed. In this step (S30), for example, ball bonding using a capillary is performed.

  Specifically, the wire 116a is bonded from the n-type electrode layer 110 of the semiconductor laser element 117 to the lead wire 119a for extracting the electrode. Further, the wire 116b is bonded from the submount electrode layer 113b to the lead wire 119b for leading the p-type electrode. At the time of wire bonding, the semiconductor laser element 117 is pressed by a capillary through the substrate 100 and bonded by ultrasonic waves. At this time, since the cavity 130 is formed between the p-type electrode layer 109a formed on the top surface of the ridge portion 117b and the submount 118, the cavity 130 serves as a cushion, and an impact applied to the ridge portion 117b. Is suppressed. Therefore, since damage to the semiconductor laser element 117 is reduced, an increase in the operating voltage of the semiconductor laser device 100a can be suppressed, there is no deterioration in efficiency, reliability can be improved, and output can be improved.

  The method of bonding in the step of electrically connecting the substrate 100 and the wire 116a (S30) is not particularly limited to ball bonding, and a generally known method can be adopted. Even in other methods, heat and load are applied from above the substrate 100, but the cavity 130 can suppress an increase in the operating voltage of the semiconductor laser device 100a.

  By performing the above steps (S10 to S30), semiconductor laser device 100a shown in FIG. 1 in the present embodiment is obtained. Note that a step (S40) of filling the cavity 130 with the solder 140 may be further performed after the step (S30) of electrically connecting the substrate 100 of the semiconductor laser element 117 and the wire 116a. The solder 140 is preferably made of a material having high thermal conductivity. When the step (S40) is performed, the heat radiation effect of the semiconductor laser device 100a can be improved by the solder 140, as shown in FIG.

  As described above, according to semiconductor laser device 100a in the first embodiment of the present invention, cavity 130 is formed between p-type electrode layer 109a and submount 118 formed on the top surface of ridge portion 117b. In the semiconductor laser element 117, the surface on which the p-type electrode layer 109a formed on the top surface of the ridge portion 117b is formed is exposed to the cavity 130. Therefore, the impact applied to the ridge portion 117b during the step of electrically connecting the substrate 100 and the wire 116a (S30) can be reduced, so that damage to the semiconductor laser element 117 is reduced. Therefore, an increase in the operating voltage of the semiconductor laser device 100a can be suppressed, there is no deterioration in efficiency, and reliability is improved, so that a high-power semiconductor laser device 100a is obtained.

(Embodiment 2)
FIG. 8 is a sectional view showing a semiconductor laser device according to the second embodiment of the present invention. With reference to FIG. 8, a semiconductor laser device according to the second embodiment of the present invention will be described. As shown in FIG. 8, the semiconductor laser device 100b in the second embodiment basically has the same configuration as the semiconductor laser device 100a in the first embodiment shown in FIG. The only difference is that a solder layer 114c is provided between the dummy ridge 117c and the mount base instead of the film 111.

  Specifically, the mounted base includes a stem 115 and a submount 118. The submount 118 is fixed to the dummy ridge portion 117c through the solder layer 114c. For example, AuSn can be used for the solder layer 114c.

  Next, with reference to FIGS. 8-12, the manufacturing method of the semiconductor laser apparatus in Embodiment 2 of this invention is demonstrated. FIG. 9 is a flowchart showing a method for manufacturing the semiconductor laser device in the second embodiment of the present invention. FIG. 10 is a schematic diagram for explaining a preparation step in the second embodiment of the present invention. FIG. 11 is a schematic diagram for explaining a process of fixing the dummy ridge portion and the mounted base in the second embodiment of the present invention. FIG. 12 is a schematic diagram showing a state after performing the step of fixing the dummy ridge portion and the mounted base in the second embodiment of the present invention.

  As shown in FIGS. 9 and 10, first, the substrate 100, the active layer 104 formed on the substrate 100, the other layer 117a formed on the active layer 104, and the other layer 117a are formed. On the surface of the other layer 117a opposite to the side facing the active layer 104, a ridge portion 117b and a dummy ridge portion 117c extending in parallel with the ridge portion 117b with the ridge portion 117b interposed therebetween are formed. The step (S10) of preparing the semiconductor laser device 117 is performed. Since this step (S10) is the same as in the first embodiment, description thereof will not be repeated.

  Next, as shown in FIGS. 9 and 10, a step (S20) of fixing the other layer 117a and the mount base in the semiconductor laser element 117 is performed. This step (S20) includes a step (S23) of placing solder (solder layer 114c) on the surface of the mount base opposite to the dummy ridge portion 117c, and the dummy ridge portion 117c and the mount target via the solder layer 114c. A step of fixing the base (S24).

  Specifically, as shown in FIG. 10, a submount 118 is prepared. The submount 118 to be prepared is basically the same as that of the first embodiment, but differs only in that the solder layer 114b is not formed.

  Subsequently, for example, a mask layer is formed in a region facing the ridge 117b in the submount electrode layer 113b of the submount 118. Then, the solder layer 114c is formed in a region where the mask layer is not formed, for example, by vapor deposition. Then, when the mask layer is removed, as shown in FIG. 10, a stripe-shaped solder layer 114c divided so as to sandwich the ridge portion 117b of the semiconductor laser element 117 is formed. Thereby, the step (S23) of placing solder (solder layer 114c) on the surface of the mount base (submount 118 in the present embodiment) facing the dummy ridge 117c.

  Thereafter, as shown in FIG. 11, the submount 118 is placed on the stem 115 so that the solder layer 114a of the submount 118 and the stem 115 face each other. Further, the semiconductor laser element 117 is mounted on the submount 118 so that the solder layer 114c of the submount 118 and the dummy ridge portion 117c of the semiconductor laser element 117 face each other with the vertical direction of the semiconductor laser element 117 reversed. In the mounted state with the junction down shown in FIG. 11, the solder layer 114c of the submount 118 is not disposed at a position facing the ridge portion 117b, so that it is provided in contact with the ridge portion 117b of the semiconductor laser device 117. A cavity is formed between the p-type electrode layer 109 a and the submount 118.

  When the temperature is raised to a temperature equal to or higher than the melting temperature of the solder layer 114c (310 ° C. in this embodiment), the solder layer 114c is melted as shown in FIG. 12, and the stem 115, the submount 118, and the semiconductor laser element 117 are melted. Are integrated. Thus, the step (S22) of fixing the dummy ridge 117c and the mount base (submount 118 in the present embodiment) via the solder layer 114c can be performed.

  Next, as shown in FIGS. 8 and 9, a step (S30) of electrically connecting the substrate 100 of the semiconductor laser element 117 and the wire 116a is performed. Since this step (S30) is the same as in the first embodiment, description thereof will not be repeated.

  By performing the above steps (S10 to S30), the semiconductor laser device 100b in the present embodiment shown in FIG. 8 can be manufactured. Similarly to the first embodiment, after the step of electrically connecting the substrate 100 of the semiconductor laser element 117 and the wire 116a (S30), the step of filling the cavity 130 with the solder 140 (S40) may be further performed. Good.

  Next, a manufacturing method of a modification of the semiconductor laser device according to the second embodiment of the present invention will be described with reference to FIG. FIG. 13 is a schematic diagram for explaining a preparation step in the modification of the second embodiment of the present invention.

  The manufacturing method of the semiconductor laser device in the modified example basically has the same configuration as the manufacturing method of the semiconductor laser device in the second embodiment, but the other layers 117a in the semiconductor laser element 117 and the mount base And only in the step of fixing (S20).

  Specifically, the step (S20) of fixing the other layer 117a and the mount base (submount 118 in this modification) in the semiconductor laser element 117 is performed on the dummy ridge 117c as shown in FIG. The method includes a step of arranging the solder layer 114e so as to be in contact with each other, and a step of fixing the dummy ridge portion 117c and the mount base via the solder layer 114e. Note that the solder layer 114e can be made of the same material as the solder layer 114c described above.

  As described above, the semiconductor laser device 100b according to the second embodiment of the present invention further includes the solder layers 114c and 114e disposed between the dummy ridge portion 117c and the mounted base. As a result, in the step of fixing the other layer 117a and the mount base (S20), the p-type electrode layer 109a formed on the top surface of the ridge 117b by the solder layers 114c and 114e and the submount 118 The cavity 130 can be easily provided therebetween.

(Embodiment 3)
FIG. 14 is a sectional view showing a semiconductor laser device according to the third embodiment of the present invention. With reference to FIG. 14, a semiconductor laser device according to Embodiment 3 of the present invention will be described. As shown in FIG. 14, the semiconductor laser device 100c in the third embodiment basically has the same configuration as that of the semiconductor laser device 100a in the first embodiment. However, a dummy ridge portion is used instead of the metal film 111. The only difference is that two or more kinds of solders (first solder layer 121b and second solder layer 120) having different melting points are provided between 117c and the mount base.

  Specifically, as shown in FIG. 14, the second solder layer is in contact with the p-type electrode layer 109 in the laminated body of the insulating film 108 and the p-type electrode layer 109 provided in contact with the dummy ridge portion 117c. 120 is formed. That is, the second solder layer 120 is provided so as to be in contact with the p-type electrode layer 109 on the dummy ridge portion 117c formed with the ridge portion 117b interposed therebetween. The first solder layer 121b is formed to be in contact with the second solder layer 120 and to be in contact with the submount electrode layer 113b in the submount 118. The first solder layer 121a is formed on the submount electrode layer 113a in the submount 118.

  The melting point of the first solder layer 121 b formed on the surface facing the semiconductor laser element 117 is lower than the melting point of the second solder layer 120. Therefore, in the semiconductor laser device 100c, the first solder layer 121b is melted and cured, so that the shape is deformed. On the other hand, the second solder layer 120 is not dissolved and hardened.

  The first solder layer 121b is not particularly limited as long as it is made of a material lower than the melting point of the second solder layer 120. For example, SnAgCu (an alloy of tin, silver and copper) can be used. The second solder layer 120 can be made of, for example, AuSn. The first solder layer 121a formed on the surface facing the stem 115 may be made of the same material as the first solder layer 121b formed on the surface facing the semiconductor laser element 117. May be made of different materials.

  Next, with reference to FIGS. 14-18, the manufacturing method of the semiconductor laser apparatus in Embodiment 3 of this invention is demonstrated. FIG. 15 is a flowchart showing a method for manufacturing the semiconductor laser device according to the third embodiment of the present invention. FIG. 16 is a schematic diagram for explaining a preparation step in the third embodiment of the present invention. FIG. 17 is a schematic diagram for explaining a process of fixing the dummy ridge portion and the mounted base in the third embodiment of the present invention. FIG. 18 is a schematic diagram for explaining the step of filling the cavity in the third embodiment of the present invention.

  As shown in FIGS. 15 and 16, the substrate 100, the active layer 104 formed on the substrate 100, another layer 117a formed on the active layer 104, and an electrode formed on the other layer 117a. And a ridge portion 117b and a dummy ridge portion 117c extending in parallel with the ridge portion 117b across the ridge portion 117b on the surface of the other layer 117a opposite to the side facing the active layer 104. A step (S10) of preparing the laser element 117 is performed. Since this step (S10) is the same as in the first embodiment, description thereof will not be repeated.

  Next, as shown in FIGS. 15 to 17, a step (S20) of fixing another layer 117a and the mount base in the semiconductor laser element 117 is performed. In this step (S20), at least one of the dummy ridge portion 117c and the mounted base is two or more kinds of solders having different melting points (in this embodiment, the first solder layer 121b and the second solder layer 120). Of the solder (S25), and the solder having a relatively low melting point (the first solder layer 121b in the present embodiment) of the solder is melted, while the solder having a relatively high melting point (the second solder in the present embodiment). It includes a step (S24) of fixing the dummy ridge portion 117c and the mount base through solder having a relatively low melting point by heating to a temperature at which the solder layer 120) does not melt.

  Specifically, as shown in FIG. 16, a submount 118 is prepared. The prepared submount 118 is basically the same as in the first embodiment, but instead of the solder layers 114a and 114b, first solder layers 121a and 121b having a melting point lower than that of the second solder layer 120 are formed. It differs only in the point to do.

  Subsequently, as shown in FIG. 16, the second solder layer 120 is formed on the dummy ridge portion 117 c sandwiching the ridge portion 117 b in the semiconductor laser element 117. Thereby, as shown in FIG. 16, the second solder layer 120 having a relatively high melting point is formed on the dummy ridge portion 117c, and the first solder layer having a relatively low melting point is disposed on the side facing the semiconductor laser element 117 in the submount 118. The solder layer 121b can be disposed.

  Thereafter, as shown in FIG. 17, the submount 118 is placed on the stem 115 so that the first solder layer 114b of the submount 118 and the stem 115 face each other. In addition, the semiconductor laser element 117 is mounted on the submount 118 with the vertical direction of the semiconductor laser element 117 reversed so that the first solder layer 121b of the submount 118 and the dummy ridge portion 117c of the semiconductor laser element 117 face each other. .

  Then, with the junction mounted as shown in FIG. 17, heating is performed so that the temperature is equal to or higher than the melting point of the first solder layer 121 b and lower than the melting point of the second solder layer 120 (for example, 270 ° C. in this embodiment). . As a result, only the first solder layer 121b is dissolved, and the second solder layer 120 is not dissolved. Therefore, the dummy ridge 117c and the submount 118 can be fixed via the first solder layer 121b and the second solder layer 120. At this time, since the second solder layer 120 is not provided in contact with the ridge portion 117 b, a cavity is formed between the ridge portion 117 b of the semiconductor laser element 117 and the submount 118.

  When the first solder layers 121a and 121b are made of the same material, the stem 115, the submount 118, and the semiconductor laser element 117 can be integrated at the same time. Therefore, since the number of steps can be reduced, the first solder layers 121a and 121b are preferably made of the same material.

  Next, as shown in FIGS. 14 and 15, a step (S30) of electrically connecting the substrate 100 of the semiconductor laser element 117 and the wire 116a is performed. Since this step (S30) is the same as that in the first embodiment, the description thereof will not be repeated.

  By performing the above steps (S10 to S30), the semiconductor laser device 100c shown in FIG. 14 is obtained.

  In order to improve the heat dissipation effect, as shown in FIG. 15 and FIG. 18, a solder having a relatively high melting point (this embodiment) among the solder (first solder layer 121b and second solder layer 120 in this embodiment) In this embodiment, it is preferable to further perform the step (S40) of embedding the cavity 130 through the solder having a relatively high melting point by heating to a temperature at which the second solder layer 120) is melted.

  Specifically, the temperature is increased again to a temperature at which the second solder layer 120 is dissolved (for example, 310 ° C. in this embodiment), and the second solder layer 120 is dissolved. As a result, the second solder layer 120 fills the cavity 130. By performing this step (S40), the semiconductor laser device 100d shown in FIG. 18 is obtained.

  Next, with reference to FIG. 15 and FIG. 19, a manufacturing method of Modification Example 1 of the semiconductor laser device according to Embodiment 3 of the present invention will be described. FIG. 19 is a schematic diagram for explaining a preparation step in the first modification of the third embodiment of the present invention.

  As shown in FIGS. 15 and 19, the preparation step (S10) in Modification 1 is basically the same as the preparation step (S10) in Embodiment 3, but the second solder layer 120 is The only difference is that the submount 118 is provided at a position facing the dummy ridge 117c so as to be in contact with the first solder layer 121b.

  Next, with reference to FIGS. 15 and 20, a manufacturing method of Modification 2 of the semiconductor laser device according to Embodiment 3 of the present invention will be described. FIG. 20 is a schematic diagram for explaining a preparation step in Modification 2 of Embodiment 3 of the present invention.

  As shown in FIGS. 15 and 20, the preparation step (S10) in Modification 2 is basically the same as that in Embodiment 3, except that the first solder layer 121b is replaced with a dummy ridge in the semiconductor laser device 117. The only difference is that the second solder layer 120 is provided on the portion 117c.

  16 to 20 described above, the first solder layer 121b is higher than the melting point of the second solder layer 120 in the step of arranging two or more kinds of solders having different melting points (S25). It is good also as another structure which consists of material.

  As described above, according to the semiconductor laser devices 100c and 100d in the third embodiment of the present invention, the two or more kinds of solders having different melting points arranged between the dummy ridge portion 117c and the submount 118 are used. A first solder layer 121b and a second solder layer 120 are further provided. The cavity 130 can be easily provided between the ridge 117b and the submount 118 by the second solder layer 120 having a relatively high melting point.

  Also, after the step of electrically connecting the substrate 100 and the wire 116a (S30), the step of electrically connecting the substrate 100 and the wire 116a by dissolving the first solder layer 120 having a relatively high melting point (see FIG. S30) Sometimes the impact applied to the semiconductor laser element 117 by the cavity 130 is reduced, and when the semiconductor laser device 100d is used, the heat dissipation can be improved by the first solder layer 121b having a relatively high melting point.

(Embodiment 4)
FIG. 21 is a sectional view showing a semiconductor laser device according to the fourth embodiment of the present invention. With reference to FIG. 21, a semiconductor laser device according to Embodiment 4 of the present invention will be described. As shown in FIG. 21, the semiconductor laser device 100e according to the fourth embodiment basically has the same configuration as that of the third embodiment, but differs in that the submount 118 is not provided.

  Specifically, in the semiconductor laser device 100 e, the semiconductor laser element 117 is connected to the stem 115 via the first solder layer 123. That is, the semiconductor laser element 117 is directly mounted on the stem 115 by junction down without using a submount. For example, SnAgCu can be used for the first solder layer 123.

  Next, with reference to FIGS. 21-24, the manufacturing method of the semiconductor laser apparatus in Embodiment 4 of this invention is demonstrated. FIG. 22 is a schematic diagram for explaining a preparation step in the fourth embodiment of the present invention. FIG. 23 is a schematic diagram for explaining a process of fixing the dummy ridge portion and the mounted base in the fourth embodiment of the present invention. FIG. 24 is a schematic diagram for explaining the step of filling the cavity in the fourth embodiment of the present invention.

  Specifically, as shown in FIGS. 15 and 21, first, the substrate 100, the active layer 104 formed on the substrate 100, another layer 117 a formed on the active layer 104, and other layers A dummy ridge portion 117c that includes an electrode formed on 117a and extends parallel to the ridge portion 117b across the ridge portion 117b and the ridge portion 117b on the surface of the other layer 117a opposite to the side facing the active layer 104. A step (S10) of preparing the semiconductor laser device 117 formed with and is performed. Since this step (S10) is the same as in the first embodiment, description thereof will not be repeated.

  Next, as shown in FIGS. 15 and 22, a step (S20) of fixing the other layer 117a and the mount base in the semiconductor laser element 117 is performed. This step (S20) is basically the same as in the third embodiment.

  Specifically, as shown in FIG. 22, the second solder layer 120 is formed on the dummy ridge portion 117 c of the semiconductor laser element 117. Subsequently, as shown in FIG. 23, a stem 115 is prepared as a mount base. Then, the first solder layer 123 is formed so as to contact the surface of the stem 115 facing the semiconductor laser element 117. The semiconductor laser element 117 is placed on the stem 115 so that the semiconductor laser element 117 is turned upside down and the stem 115 faces the side of the semiconductor laser element 117 where the dummy ridge 117c is formed. In the mounted state with the junction down, the temperature rises to a temperature at which the first solder layer 123 melts (270 ° C. in the present embodiment), and only the first solder layer 123 is melted. As a result, the semiconductor laser element 117 can be fixed on the stem 115 via the first solder layer 123 and the second solder layer 120.

  Next, a step (S30) of electrically connecting the substrate 100 of the semiconductor laser element 117 and the wire 116a is performed. Since this step (S30) is the same as that in the first embodiment, the description thereof will not be repeated. The semiconductor laser device 100e shown in FIG. 21 can be manufactured by performing the above steps (S10 to S30).

  Next, heating is performed to a temperature at which a relatively high melting point solder (second solder layer 120 in this embodiment) of the solder (first solder layer 123 and second solder layer 120 in this embodiment) melts. Thus, the step of filling the cavity 130 through the solder having a relatively high melting point (S40). Since this step (S40) is the same as that in the third embodiment, the description thereof will not be repeated.

  By performing the above steps (S10 to S40), the semiconductor laser device 100f shown in FIG. 24 can be manufactured.

  As described above, according to the semiconductor laser device 100f according to the fourth embodiment of the present invention, the mount base includes the stem 115. Thereby, since the structural member of the semiconductor laser apparatus 100f can be reduced, manufacturing cost can be reduced.

(Invention Example 1)
The semiconductor laser device of Example 1 of the present invention was manufactured according to the manufacturing method of the semiconductor laser device in the first embodiment. Specifically, in the preparing step (S10), the substrate 100 made of n-type GaN and having a thickness of 100 μm and the n-type buffer layer 101 made of n-type GaN and having a thickness of 0.2 μm. And an n-type cladding layer 102 having a thickness of 2.0 μm, an n-type guide layer 103 having a thickness of 20 nm, an InGaN well layer, and a GaN barrier layer. An active layer 104 having a multiple quantum well structure in which three layers are stacked, a well layer having a thickness of 4 nm and a barrier layer having a thickness of 8 nm, and a p-type evaporation preventing layer 105 made of AlGaN and having a thickness of 20 nm, A p-type cladding layer 106 made of AlGaN and having a thickness of 0.55 μm; and a p-type contact layer 107 made of GaN and having a thickness of 0.1 μm; An insulating film 108 made of SiO ₂ and having a thickness of 0.2 μm, a p-type electrode layer 109 made of Pd and Au, having a Pd thickness of 50 nm and an Au thickness of 0.2 μm, A semiconductor laser element including an n-type electrode layer 110 made of Au and having a thickness of Hf of 50 nm, a thickness of Pt of 0.1 μm, and a thickness of Au of 0.2 μm was prepared.

  Next, the metal film 111 has a thickness (thickness L in FIG. 1) of 0.5 μm, and a p-type electrode layer 109 in which a plating layer made of Au is formed on the dummy ridge portion 117 c of the semiconductor laser element 117. Formed on top.

  Next, as the submount 118, a submount material 112 made of SiC and having a thickness of 300 μm and Ti, Pt, and Au are laminated, and the thickness of Ti is 0.1 μm and the thickness of Pt is 0. Sub-mount electrode layers 113a and 113b with a thickness of 0.2 μm and Au of 0.2 μm and solder layers 114a and 114b made of AuSn and having a thickness of 5 μm and 3 μm, respectively, were prepared. Next, a stem made of Cu and having a thickness of 1 mm was prepared.

  Next, the submount 118 is disposed on the stem 115, the semiconductor laser element 117 is disposed on the submount 118, and the solder layers 114a, 114b are melted and cured by setting the temperature to 310 ° C. It was integrated via 114b. As a result, the other layers in the semiconductor laser element 117 and the mount base were fixed.

  Next, a capillary was dropped on the substrate 100 of the semiconductor laser element 117 to perform wire bonding, and the substrate 100 of the semiconductor laser element 117 and the wires 116a and 116b made of Au were electrically connected.

  By performing the above steps, the semiconductor laser device 100a according to Example 1 of the present invention was manufactured. In the semiconductor laser device of Inventive Example 1, a cavity 130 is formed between the electrode formed on the top surface of the ridge portion 117b and the mounted base, and the top surface of the ridge portion 117b in the semiconductor laser element 117 is formed. The electrode formed in (1) was exposed in the cavity 130.

(Invention Example 2)
The semiconductor laser device of Example 2 of the present invention was manufactured basically in the same manner as Example 1 of the present invention, except that the thickness of the metal film 111 was 5 μm.

(Invention Example 3)
The semiconductor laser device of Inventive Example 3 was manufactured basically in the same manner as in Inventive Example 1, except that the thickness of the metal film 111 was 3 μm.

(Invention Example 4)
The semiconductor laser device of Inventive Example 4 was manufactured basically in the same manner as in Inventive Example 1, except that the thickness of the metal film 111 was 0.2 μm.

(Invention Example 5)
The semiconductor laser device of Inventive Example 5 was manufactured basically in the same manner as in Inventive Example 1, except that the thickness of the metal film 111 was 10 μm.

(Comparative Example 1)
The semiconductor laser device in Comparative Example 1 was basically manufactured in the same manner as in Example 1 of the present invention, except that the substrate 100 of the semiconductor laser element 117 and the submount 118 were fixed (mounted at junction up), and The only difference is that the capillary is dropped on the p-type electrode layer 109a formed on the ridge portion 117b and wire bonding is performed to electrically connect the semiconductor laser element and the wire.

(Comparative Example 2)
The semiconductor laser device in Comparative Example 2 is basically the same as that in Comparative Example 1, except that the capillary is dropped on the p-type electrode on the dummy ridge and wire bonding is performed.

(Comparative Example 3)
The semiconductor laser device in Comparative Example 3 is basically the same as in Comparative Example 1, but the semiconductor laser element and the submount are fixed without a cavity by junction down, and the capillary is dropped on the substrate to perform wire bonding. It differs only in the point made.

(Measuring method)
For the semiconductor laser devices in Invention Examples 1 to 5 and Comparative Examples 1 to 3, the operating voltage Vop was injected into the semiconductor laser device, and the voltage value was measured when the optical output reached 100 mW.

(Measurement result)
The operating voltage Vop of the semiconductor laser device of Comparative Example 1 in which the capillary was dropped on the ridge portion and wire-bonded was higher than that of the semiconductor laser device of Comparative Example 2 in which the capillary was dropped and not bonded to the ridge portion. I understood. The present inventor considered that this is because the strong stress was applied to the ridge due to the impact when the capillary was lowered onto the ridge during wire bonding and the impact caused by the ultrasonic wave during bonding, and the operating voltage Vop increased. .

  In addition, the semiconductor laser device of Comparative Example 3 in which the capillary was dropped by junction-down without providing a cavity between the semiconductor laser element and the submount and wire-bonded by dropping the capillary on the ridge by junction-up. As in Comparative Example 1, it was found that the operating voltage Vop was increased as compared with Comparative Example 2 in which the capillary was dropped so as not to hit the ridge by junction-up and wire bonding was performed. The inventor considered that this is because wire bonding is performed in a state where the ridge portion is pressed against the submount due to the junction down, and stress is applied to the ridge portion to increase the operating voltage Vop.

  From the above, the present inventor has found that when a conventional semiconductor laser device of a double channel type is mounted with junction-down, the operating voltage is increased and the reliability is lowered as compared with the case of mounting with junction-up. It was. In addition, the increase in operating voltage of the semiconductor laser device mounted at the junction down is caused by damage to the semiconductor laser element due to an impact applied when the semiconductor laser element is wire-bonded. The inventor found.

  On the other hand, in the semiconductor laser devices of Examples 1 to 5 of the present invention, the operating voltage Vop was not increased as compared with the semiconductor laser device of Comparative Example 2 mounted by normal junction up. For this reason, since the semiconductor laser devices of Examples 1 to 5 of the present invention are mounted by junction-down, a highly reliable semiconductor laser device can be obtained even at high output operation as compared with the semiconductor laser device mounted by junction-up. I was able to confirm.

  The operating voltages of the semiconductor laser devices according to Invention Examples 1 to 5 were almost the same as those of Comparative Example 2. In particular, Examples 1 and 2 of the present invention having a metal film thickness of 0.5 μm or more and 5 μm or less were provided with a sufficient and not too large cavity, so that the operating voltage could be reduced and the heat dissipation effect was good. It was. From the above, it was confirmed that the operating voltage Vop and the reliability were compatible when the thickness of the metal film 111 was 0.5 μm or more and 5 μm or less.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is shown not by the above-described embodiment but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 is a schematic perspective view showing a semiconductor laser device according to a first embodiment of the present invention. 3 is a flowchart showing a method for manufacturing the semiconductor laser device in the first embodiment of the present invention. It is a schematic diagram for demonstrating the process prepared in Embodiment 1 of this invention. It is another schematic diagram for demonstrating the process prepared in Embodiment 1 of this invention. It is a schematic diagram for demonstrating the process of fixing the dummy ridge part and to-be-mounted base in Embodiment 1 of this invention. It is a schematic diagram which shows the state after implementing the process which fixes the dummy ridge part and to-be-mounted base in Embodiment 1 of this invention. It is a schematic diagram for demonstrating the process of embedding the cavity with solder in Embodiment 1 of this invention. It is sectional drawing which shows the semiconductor laser apparatus in Embodiment 2 of this invention. It is a flowchart which shows the manufacturing method of the semiconductor laser apparatus in Embodiment 2 of this invention. It is a schematic diagram for demonstrating the process prepared in Embodiment 2 of this invention. It is a schematic diagram for demonstrating the process of fixing the dummy ridge part and to-be-mounted base in Embodiment 2 of this invention. It is a schematic diagram which shows the state after implementing the process of fixing the dummy ridge part and mounted base in Embodiment 2 of this invention. It is a schematic diagram for demonstrating the process to prepare in the modification of Embodiment 2 of this invention. It is sectional drawing which shows the semiconductor laser apparatus in Embodiment 3 of this invention. It is a flowchart which shows the manufacturing method of the semiconductor laser apparatus in Embodiment 3 of this invention. It is a schematic diagram for demonstrating the process prepared in Embodiment 3 of this invention. It is a schematic diagram for demonstrating the process of fixing the dummy ridge part and to-be-mounted base in Embodiment 3 of this invention. It is a schematic diagram for demonstrating the process of embedding the cavity in Embodiment 3 of this invention. It is a schematic diagram for demonstrating the process prepared in the modification 1 of Embodiment 3 of this invention. It is a schematic diagram for demonstrating the process prepared in the modification 2 of Embodiment 3 of this invention. It is sectional drawing which shows the semiconductor laser apparatus in Embodiment 4 of this invention. It is a schematic diagram for demonstrating the process prepared in Embodiment 4 of this invention. It is a schematic diagram for demonstrating the process of fixing the dummy ridge part and to-be-mounted base in Embodiment 4 of this invention. It is a schematic diagram for demonstrating the process of embedding the cavity in Embodiment 4 of this invention.

Explanation of symbols

  100a, 100b, 100c, 100d, 100e, 100f Semiconductor laser device, 100 substrate, 101 n-type buffer layer, 102 n-type cladding layer, 103 n-type guide layer, 104 active layer, 105 p-type evaporation prevention layer, 106 p-type Cladding layer, 107 p-type contact layer, 108 insulating film, 109, 109a p-type electrode layer, 110 n-type electrode layer, 111 metal film, 112 submount material, 113a, 113b submount electrode layer, 114a, 114b, 114c, 114e solder layer, 115 stem, 116a, 116b wire, 117 semiconductor laser element, 117a other layer, 117b ridge portion, 117c dummy ridge portion, 118 submount, 119a, 119b lead wire, 120 second solder layer, 121a, 121b , 123 1st Solder layer, 130 cavity, 140 solder.

Claims (2)

A substrate, an active layer formed on the substrate, another layer formed on the active layer, and an electrode formed on the other layer, and the active layer in the other layer Preparing a semiconductor laser device in which a ridge portion and a dummy ridge portion extending in parallel with the ridge portion with the ridge portion interposed therebetween are formed on the surface opposite to the opposite side;
Fixing the other layer and the mount base in the semiconductor laser element;
Electrically connecting the substrate and the wire of the semiconductor laser element;
After electrically connecting the substrate and the wire, a step of filling a cavity formed between the semiconductor laser element and the mounted base,
The step of fixing the other layer and the mounted base includes
Disposing two or more kinds of solders having different melting points on at least one of the dummy ridge portion and the mount base; and
By heating to a temperature at which the solder having a relatively low melting point of the solder melts while the solder having a relatively high melting point does not melt, the electrode formed on the top surface of the ridge portion and the coated layer are heated. The cavity is formed between the mount base and the relatively low melting point so as to expose the electrode formed on the top surface of the ridge portion of the semiconductor laser element to the cavity. A step of fixing the dummy ridge portion and the mounted base through solder,
The step of filling the cavity includes a step of filling the cavity through the solder having a relatively high melting point by heating to a temperature at which the solder having a relatively high melting point of the solder is melted. Device manufacturing method. In the step of disposing two or more kinds of solders having different melting points, the solder having a relatively high melting point is sandwiched between the ridge portion and the mounted base opposite to the ridge portion. Semiconductor laser device manufacturing method arranged to avoid

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