JP5722553B2 - Semiconductor laser device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a semiconductor laser device and a manufacturing method thereof, and more particularly to a semiconductor laser device mounted with a semiconductor laser chip made of a nitride compound semiconductor and a manufacturing method thereof.

  Nitride-based semiconductors such as GaN, AlGaN, GaInN, and AlGaInN have characteristics that they have a large band gap Eg and are direct transition semiconductor materials compared to AlGaInAs-based semiconductors and AlGaInP-based semiconductors. Therefore, these nitride semiconductors constitute semiconductor light emitting devices such as semiconductor laser devices capable of emitting light in the wavelength range from ultraviolet to green and light emitting diodes capable of covering a wide emission wavelength range from ultraviolet to red. It is attracting attention as a material and is widely considered for high-density optical discs, full-color displays, and environmental / medical fields.

Since this nitride-based semiconductor has higher thermal conductivity than a GaAs-based semiconductor, it is expected to be applied as an element operating at high temperature and high output. Further, arsenic (As) is used in AlGaAs semiconductors and cadmium (Cd) is used in ZnCdSSe semiconductors, whereas nitride semiconductors do not contain such harmful materials. In addition, ammonia (NH ₃ ) used as a raw material is less toxic than arsine (AsH ₃ ), which is a raw material for AlGaAs semiconductors. For this reason, it is also expected as a compound semiconductor material with a small environmental load.

  In recent years, a semiconductor laser chip including an active layer (light emitting layer) made of a nitride semiconductor typified by GaN, InN, AlN and mixed crystal semiconductors thereof has been put into practical use. On-board semiconductor laser devices are being produced. Such a semiconductor laser device is also disclosed in Patent Documents 1 and 2, for example.

  Conventionally, in a semiconductor laser device mounted with a semiconductor laser chip, a semiconductor laser device (semiconductor light emitting device) provided with a light receiving element for monitoring to monitor the light output in order to stabilize the light output from the semiconductor laser chip. Is also known.

  In normal semiconductor laser device assembly, after mounting a semiconductor laser chip on a heat sink, a metal paste such as Ag paste is placed on the mounting portion of the support base, and a heat sink on which the semiconductor laser chip is mounted is mounted thereon. To do. After mounting, the metal paste is cured in an oven to fix the heat sink to the support substrate. When attaching the light receiving element, similarly to the above, a metal paste is placed on the mounting portion of the light receiving element on the support base, and the light receiving element is mounted thereon and cured in an oven. Thereby, the light receiving element is fixed to the support base. Thereafter, cap sealing is performed.

  In recent years, in infrared and red semiconductor lasers, cap sealing is performed using a glassless cap to reduce the price, and the laser element is configured to be open air. However, in a short-wavelength laser element with an oscillation wavelength of 600 nm or less, when open air is used, the laser light decomposes siloxane in the atmosphere and adheres to the emission end face, thereby degrading the laser element. Further, when moisture in the atmosphere adheres to the laser element, the drive voltage and drive current increase. For this reason, in a short wavelength laser element, it is common to carry out airtight sealing with the cap with glass.

JP 2003-31895 A JP 10-12777 A

  Here, the metal paste used for mounting contains an epoxy resin, and this epoxy resin serves as a binder for the metal particles to adhere the heat sink and the light receiving element to the support base. Since this epoxy resin continues to emit gas even after thermosetting, when the laser element is hermetically sealed, the gas emitted from the epoxy resin accumulates in the laser device (in the cap). In particular, during the driving of the laser element, the temperature of the element rises so that more gas is emitted. This gas is mainly organic and is decomposed by the laser beam and adheres to the emission end face. This causes a problem that the laser element deteriorates.

  In order to solve the above problems, conventionally, a method is known in which a heat sink or a light receiving element on which a semiconductor laser chip is mounted is fixed to a support base using a metal solder foil such as AuSn instead of a metal paste. However, since metal solder does not contain organic substances, no gas is emitted. However, when heat is applied after fixing, the metal solder and Au (gold) on the surface of the laser element, heat sink and light receiving element cause mutual diffusion, and the mount There is a problem that the strength decreases.

In particular, in a semiconductor laser device using a nitride-based semiconductor laser chip, baking is performed at 100 ° C. or higher, preferably 250 ° C. or higher immediately before hermetic sealing, in order to suppress deterioration due to adhesion of moisture and siloxane to the semiconductor laser chip. There is a need to. In addition, if the support substrate is heated at a temperature higher than 200 ° C. before wire bonding, gold and nickel of the plating on the support substrate cause mutual diffusion, and the wire cannot be successfully hit on the support substrate during wire bonding. The inconvenience arises. For this reason, it is necessary to perform the baking after wire bonding, that is, after fixing the semiconductor laser chip to the support substrate.

  Therefore, when metal solder is used, the composition of the metal solder changes due to interdiffusion between Au and solder due to baking. Therefore, as described above, the mounting strength of the laser element, the heat sink, the light receiving element, and the support base is high. There is a problem that it decreases. Further, when the baking temperature exceeds the melting point of the solder, there is a problem that the solder is melted, the semiconductor laser chip is displaced, and the bonding strength is lowered.

  The present invention has been made to solve the above-described problems, and one object of the present invention is to provide a semiconductor laser device having a high yield and a long life by improving the mounting strength and a method for manufacturing the same. It is to be.

  In order to achieve the above object, a semiconductor laser device according to a first aspect of the present invention includes a semiconductor laser chip made of a nitride-based compound semiconductor and a support base that supports the semiconductor laser chip. The semiconductor laser chip is attached to the support base with a low melting point curable metal adhesive.

  In the semiconductor laser device according to the first aspect, as described above, the semiconductor laser chip is attached to the support base with the low melting point curable metal adhesive, thereby suppressing the deterioration of the semiconductor laser chip and the decrease in the mounting strength. it can.

  Here, in the “low melting point metal adhesive” in the present invention, the metal particles covered with the protective film are suspended in the solvent, and the protective metal film is removed by heating and the surface of the active metal particles is removed. appear. Then, the metal particles and the metal particles and the adherend are brought into contact with each other, thereby causing mutual diffusion and bonding. For this reason, since the diffusion proceeds as the temperature increases, the adhesive strength increases. Therefore, for example, when baking is performed at a temperature of 250 ° C. or higher, the adhesive strength does not decrease, but rather becomes stronger, so that a decrease in mount strength can be suppressed. In addition, by performing baking after wire bonding, moisture, siloxane, and the like can be removed, so that deterioration due to adhesion of moisture and siloxane to the semiconductor laser chip can be suppressed.

  The low melting point curable metal adhesive is heated to evaporate organic substances contained in the solvent, and other substances such as organic substances are not involved for adhesion. For this reason, since it can suppress that the gas which consists of organic substances accumulates in a semiconductor laser apparatus, this suppresses that the gas which consists of organic substances decomposes | disassembles with a laser beam, and adheres to an output end surface. can do. As a result, deterioration of the semiconductor laser chip can be suppressed.

  The semiconductor laser device according to the first aspect may further include a heat sink on which the semiconductor laser chip is mounted. In this case, at least one of the low melting point curable metal adhesives is preferably used for bonding the semiconductor laser chip and the heat sink and between the heat sink and the support base.

  In the semiconductor laser device according to the first aspect, the semiconductor laser chip may be directly bonded to the support base with a low melting point metal adhesive, for example, without using a heat sink.

  The semiconductor laser device according to the first aspect may further include a light-receiving element for monitoring that detects light from the semiconductor laser chip. In this case, it is preferable that the light receiving element is bonded to the support base with a low melting point curable metal adhesive.

  In the semiconductor laser device according to the first aspect, preferably, the low melting point curable metal adhesive is an adhesive that does not contain an epoxy resin in the adhesive layer before curing. If comprised in this way, since it can suppress easily that gas accumulates in a semiconductor laser apparatus, degradation of a semiconductor laser chip can be suppressed easily.

  In the semiconductor laser device according to the first aspect, it is preferable that the metal material constituting the low melting point curable metal adhesive includes at least one of gold, silver, platinum, and palladium.

  In the semiconductor laser device according to the first aspect, preferably, the low-melting-point curable metal adhesive includes metal particles having a diameter of 10 μm or less, and is configured to be bonded by bonding the metal particles during curing. Yes. If comprised in this way, the fall of mount strength can be suppressed easily.

  In the semiconductor laser device according to the first aspect, the semiconductor laser chip is preferably hermetically sealed.

  In the semiconductor laser device according to the first aspect, the oscillation wavelength of the semiconductor laser chip is preferably 600 nm or less.

  According to a second aspect of the present invention, there is provided a method of manufacturing a semiconductor laser device, comprising: preparing a support base provided with a lead pin; and a semiconductor laser chip made of a nitride compound semiconductor, using a low melting point curable metal adhesive. The step of attaching to the support base, the step of wire bonding to electrically connect the semiconductor laser chip and the lead pins provided on the support base, and the attaching of the cap to the support base make the semiconductor laser chip hermetically sealed And a step of baking the support base and the cap at a temperature of 250 ° C. or more after wire bonding and before hermetic sealing.

  In the method of manufacturing the semiconductor laser device according to the second aspect, as described above, after the wire bonding and before the hermetic sealing, the support base and the cap are baked at a temperature of 250 ° C. or higher to obtain moisture or siloxane. Therefore, it is possible to suppress deterioration caused by moisture and siloxane adhering to the semiconductor laser chip. In addition, by attaching the semiconductor laser chip to the support substrate using a low melting point curable metal adhesive, even when baked at a temperature of 250 ° C. or higher, the adhesive strength does not decrease, but rather the strength is increased. Can be suppressed. In addition, as described above, the low melting point curable metal adhesive is stable even at a high temperature. Therefore, even when baked at a temperature of 250 ° C. or higher, even when using metal solder, the low melting point curable metal adhesive is dissolved. Due to this, it is possible to suppress the positional deviation of the semiconductor laser chip and the decrease in bonding strength.

  As described above, according to the present invention, it is possible to easily obtain a high-yield, long-life semiconductor laser device and its manufacturing method by improving the mounting strength.

1 is a perspective view of a semiconductor laser device according to a first embodiment of the present invention (a view with a cap attached). 1 is a perspective view of a semiconductor laser device according to a first embodiment of the present invention (a view with a cap removed). It is sectional drawing which showed the mounting state of the semiconductor laser chip in the semiconductor laser apparatus by 1st Embodiment of this invention. It is the top view which showed the mounting state of the semiconductor laser chip in the semiconductor laser apparatus by 1st Embodiment of this invention. It is the perspective view which showed an example of the semiconductor laser chip mounted in the semiconductor laser apparatus by 1st Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the semiconductor laser apparatus by 1st Embodiment of this invention. It is a side view for demonstrating the manufacturing method of the semiconductor laser apparatus by 1st Embodiment of this invention. It is a perspective view for demonstrating the manufacturing method of the semiconductor laser apparatus by 1st Embodiment of this invention. 3 is a graph showing I _op travel data of Example 1. 6 is a graph showing I _op travel data of Comparative Example 1. 10 is a graph showing I _op travel data of Comparative Example 2. It is a perspective view (figure of a state where a cap was removed) of a semiconductor laser device by a 2nd embodiment of the present invention. It is a perspective view (figure of a state where a cap was removed) of a semiconductor laser device by a 3rd embodiment of the present invention. It is a side view for demonstrating the semiconductor laser apparatus by 3rd Embodiment of this invention. It is a side view for demonstrating the semiconductor laser apparatus by 3rd Embodiment of this invention (the figure of the state which removed the cap).

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments embodying the present invention will be described in detail with reference to the drawings.

(First embodiment)
1 and 2 are perspective views of the semiconductor laser device according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view showing a mounting state of the semiconductor laser chip in the semiconductor laser device according to the first embodiment of the present invention. 4 and 5 are diagrams for explaining the configuration of the semiconductor laser device according to the first embodiment of the present invention. FIG. 1 shows a diagram with the cap attached, and FIG. 2 shows a diagram with the cap removed. First, the structure of the semiconductor laser device according to the first embodiment of the invention will be described with reference to FIGS.

  As shown in FIG. 1, the semiconductor laser device according to the first embodiment is a can package type semiconductor laser device, and the oscillation wavelength of emitted laser light is 600 nm or less.

  As shown in FIGS. 1 and 2, the semiconductor laser device according to the first embodiment includes a semiconductor laser chip 100 (see FIG. 2), a heat sink 200 (see FIG. 2), a metal stem 300, and a cap 400 (see FIG. 2). 1) and three lead pins 50-52.

  The semiconductor laser chip 100 is made of a nitride semiconductor and is formed so that its oscillation wavelength is 600 nm or less. As shown in FIG. 5, the semiconductor laser chip 100 has a structure in which a stacked body 20 including a plurality of nitride-based semiconductor layers is formed on an n-type GaN substrate 10. The stacked body 20 has a structure in which an n-type nitride-based semiconductor layer 21, a light emitting layer (active layer) 22, and a p-type nitride-based semiconductor layer 23 are sequentially formed from the n-type GaN substrate 10 side. doing. Each of the n-type nitride semiconductor layer 21 and the p-type nitride semiconductor layer 23 includes one or more semiconductor layers.

The stacked body 20 (p-type nitride-based semiconductor layer 23) of the semiconductor laser chip 100 is formed with a ridge portion 24 having a convex cross section, and on both sides of the ridge portion 24, SiO ₂ or A buried layer 25 made of a dielectric film such as TiO ₂ is formed. As a result, the path of the current injected into the element is narrowed to increase the light emission efficiency, and the oscillation threshold current is reduced.

  Furthermore, a p-side electrode 26 is formed on the upper surface of the stacked body 20. On the other hand, an n-side electrode 27 is formed on the lower surface of the n-type GaN substrate 10, and a metal multilayer film 28 for metallization is formed on the lower surface of the n-side electrode 27.

  The above configuration is the basic configuration of the semiconductor laser chip 100 mounted on the semiconductor laser device.

  In the first embodiment, as shown in FIGS. 2 and 3, the semiconductor laser chip 100 is fixed and stacked on the stem 300 via the heat sink 200.

  The heat sink 200 is made of AlN, and as shown in FIG. 3, a Ti layer (not shown), a Pt layer (not shown), and an Au layer (not shown) are sequentially laminated on both sides from the heat sink 200 side. Metal multilayer films 210 and 220 having a laminated structure are formed.

  As shown in FIG. 2, the stem 300 is made of a metal material such as iron or copper, and is formed in a disk shape. A block portion 350 having a heat radiation function is provided on the upper surface side of the stem 300. Further, through holes 310 and 320 through which the lead pins 51 and 52 are inserted are formed in predetermined portions of the stem 300. The stem 300 provided with the block portion 350 is an example of the “support base” in the present invention.

  Of the three lead pins 50, 51 and 52, the lead pin 50 is directly attached to the stem 300. On the other hand, among the three lead pins 50, 51, and 52, the lead pins 51 and 52 are inserted through the through holes 310 and 320 so that one end portions protrude to the upper surface side of the stem 300. Then, it is insulated and fixed to the stem 300 via the insulator 60.

  As shown in FIG. 1, the cap 400 is attached on the upper surface of the stem 300 so as to cover the semiconductor laser chip 100 (see FIG. 2) and the like. The cap 400 is made of a metal material such as copper, and is formed in a cylindrical shape with one surface open. Further, a flange portion 410 is provided at the open end of the cap 400, and an emission hole 420 for extracting laser light emitted from the semiconductor laser chip 100 (see FIG. 5) is provided at the closed end of the cap 400. Is provided. The exit hole 420 is covered with a glass window 430. The glass window 430 is coated with a transmittance of 98% or more at the oscillation wavelength ± 20 nm of the semiconductor laser chip 100.

  The cap 400 is fixed on the upper surface of the stem 300 so that the flange portion 410 is welded to the stem 300 to cover the semiconductor laser chip 100 and the like. The cap 400 hermetically seals the semiconductor laser chip 100.

Further, as shown in FIG. 3, the semiconductor laser chip 100 is mounted on the heat sink 200 in a junction-up manner. Specifically, the semiconductor laser chip 100 is bonded onto the heat sink 200 via the solder layer 510 and the metal multilayer film 210 with the p-side electrode 26 facing upward. As shown in FIGS. 3 and 4, the solder layer 510 is made of, for example, Au _0.7 Sn _0.3 , and is formed in advance on the metal multilayer film 210 of the heat sink 200 by vapor deposition or the like.

  Here, in the first embodiment, the heat sink 200 on which the semiconductor laser chip 100 is mounted is bonded onto the block part 350, and a low melting point curable metal adhesive (low temperature) is used for bonding the heat sink 200 and the block part 350. A curable metal adhesive) is used. Specifically, the heat sink 200 is bonded to the block portion 350 via an adhesive layer 610 formed from the metal multilayer film 220 and the low melting point curable metal adhesive 600.

  A low-melting-point curable metal adhesive is a metal particle with a diameter of 10 μm or less covered with a surface stabilizer (protective film) drifting in a solvent made of an organic substance. When the surface stabilizer is decomposed by heating, the metal particle An active point appears on the surface of. In the first embodiment, the metal particles are made of Ag particles having a diameter of several microns. Moreover, since organic substance evaporates by heating, while the metal particle which the active point appeared will contact, a metal particle will contact the adhesion target object (Au layer in 1st Embodiment). And this active site reacts (interdiffusion), metal particles (Ag particles) adhere to each other, and Ag particles and Au layer adhere to each other. For this reason, other substances such as organic substances are not involved for adhesion, and only Ag and Au are detected even if material analysis is performed. The low melting point curable metal adhesive is also an adhesive that does not contain an epoxy resin in the adhesive layer 610 before curing.

  As shown in FIGS. 2 and 3, the p-side electrode 26 of the semiconductor laser chip 100 is electrically connected to the lead pin 51 through a metal wire 70 (71). On the other hand, the n-side electrode 27 of the semiconductor laser chip 100 is electrically connected to the lead pin 52 via the metal wire 70 (72). That is, the semiconductor laser device according to the first embodiment is a floating mount. Note that the lead pins 51 and 52 are connected to an external connection terminal (not shown) that is insulated from the stem 300, whereby current can be supplied to the semiconductor laser chip 100 from the outside.

  6 to 8 are views for explaining the method of manufacturing the semiconductor laser device according to the first embodiment of the invention. Next, with reference to FIGS. 4 and 6 to 8, a method for manufacturing the semiconductor laser device according to the first embodiment of the invention will be described.

  First, the AuSn solder 500 (see FIGS. 4 and 6) deposited on the heat sink 200 is melted by heating the heat sink 200 to 320 ° C., and as shown in FIG. Mounted on the heat sink 200 on the lower side. Then, the semiconductor laser chip 100 and the heat sink 200 are well adapted to the AuSn solder 500 while further applying a load with the collet 900 as appropriate. Thereafter, the heat sink 200 is cooled to solidify the AuSn solder 500. As a result, the semiconductor laser chip 100 is fixed on the heat sink 200 via the solder layer 510.

  Next, as shown in FIG. 7, a low melting point curable metal adhesive 600 is applied to the block portion 350 of the stem 300, and the heat sink 200 on which the semiconductor laser chip 100 is loaded is applied. Place on top and apply load. Then, the stem 300 on which the semiconductor laser chip 100 and the heat sink 200 are loaded is placed in an oven at 200 ° C. for 1 hour to vaporize and blow off the organic material of the low melting point curable metal adhesive 600, and the low melting point curable metal adhesive 600 is removed. This step is finished when the resin is cured.

  Next, as shown in FIG. 8, the semiconductor laser chip 100 and the lead pins 51 and 52 are electrically connected by wire bonding.

  Subsequently, the cap 400 having the stem 300 and the glass window 430 on which the semiconductor laser chip 100 is loaded in vacuum or in dry air with a dew point of −20 ° C. or lower is heated and baked at a temperature of 250 ° C. or higher (for example, 280 ° C.) for 30 minutes. Then, the organic substances and moisture in the stem 300 and the cap 400 are removed by evaporation. Then, the semiconductor laser chip 100 is hermetically sealed by attaching the cap 400 to the stem 300 in an atmosphere of dry air having a dew point of −20 ° C. or less without being exposed to the air. Thus, the semiconductor laser device according to the first embodiment of the present invention is manufactured.

  In the semiconductor laser device according to the first embodiment, as described above, the semiconductor laser chip 100 is attached to the support base with the low melting point curable metal adhesive 600, thereby suppressing the deterioration of the semiconductor laser chip and the decrease in the mounting strength. Can do.

  In the low melting point curable metal adhesive 600, as described above, Ag particles covered with a protective film are suspended in a solvent, and the surface of the active Ag particles is removed by heating to remove the protective film. appear. Then, the Ag particles and the Ag particles and the adherend (Au layer) come into contact with each other to cause mutual diffusion and adhere. For this reason, since the diffusion proceeds as the temperature increases, the adhesive strength increases. Therefore, when baking is performed at a temperature of 250 ° C. or higher (for example, 280 ° C.), the adhesive strength does not decrease but rather becomes stronger, so that a decrease in mount strength can be suppressed. In addition, since baking, siloxane, and the like can be removed by baking after wire bonding, deterioration due to adhesion of moisture and siloxane to the semiconductor laser chip 100 can be suppressed.

  The low melting point curable metal adhesive 600 evaporates an organic substance contained in a solvent or the like by heating, and other substances such as an organic substance are not involved for adhesion. For this reason, since it can suppress that the gas which consists of organic substances accumulates in a semiconductor laser device (cap 400), the gas which consists of organic substances is decomposed | disassembled by a laser beam and this adheres to an output end surface. Can be suppressed. As a result, deterioration of the semiconductor laser chip 100 can be suppressed.

  In addition, by suppressing the deterioration of the semiconductor laser chip 100, the life of the semiconductor laser device can be extended. Further, by suppressing the decrease in mount strength, it is possible to suppress the decrease in yield. Further, as described above, the low melting point curable metal adhesive 600 is stable even at a high temperature as described above. Therefore, even when baked at a temperature of 250 ° C. or higher or when using a metal solder, the melting point is found. It is possible to suppress the positional deviation of the semiconductor laser chip 100 and the decrease in bonding strength due to the extraction.

  Next, in order to confirm the effect of the above-described embodiment, a semiconductor laser device similar to the semiconductor laser device shown in the first embodiment was used as Example 1, and the following Comparative Examples 1 and 2 were compared. .

Comparative Example 1 is a semiconductor laser device using a metal solder foil made of Au _0.7 Sn _0.3 instead of the low melting point curable metal adhesive. In Comparative Example 1, a 50 μm thick metal solder foil was placed on the stem block and heated to 310 ° C., and a heat sink with a semiconductor laser chip mounted thereon was placed on the melted metal solder foil and a load was applied. After that, the heat sink was cooled and fixed.

  Comparative Example 2 is a semiconductor laser device using an Ag paste containing an epoxy resin instead of the low melting point curable metal adhesive. In Comparative Example 2, first, Ag paste was applied on the block portion of the stem, and a heat sink on which a semiconductor laser chip was loaded was placed thereon and a load was applied. Thereafter, the stem loaded with the semiconductor laser chip and the heat sink was placed in an oven at 160 ° C. for 1 hour to cure the Ag paste, and the heat sink was fixed.

  Eighty samples of the semiconductor laser devices of Example 1 and Comparative Examples 1 and 2 described above were produced, and the following measurements were performed.

  First, the die shear strength of the heat sink on which the semiconductor laser chip was loaded was measured using 30 semiconductor laser devices of 80 manufactured. Specifically, the heat sink fixed on the stem was pushed in the horizontal direction from the side, and the load value at which the heat sink peeled from the stem, that is, the shear strength (die shear strength) of the heat sink was measured.

  The average value of 30 die shear strengths was 5.2 N in Example 1, 2.7 N in Comparative Example 1, and 3.1 N in Comparative Example 2.

  Next, a drop test was performed in which the remaining 50 pieces were placed in a tray and dropped from a height of 60 cm. As a result, in Example 1 and Comparative Example 2, nothing was removed from the heat sink, but in Comparative Example 1, the heat sink was peeled off from the stem in eight of the 50 semiconductor laser devices. In the semiconductor laser device of Comparative Example 1, since the metal solder foil for bonding the heat sink and the stem is thick, the solder is melted by the heat baking of the cap seal. It is thought that the device was generated.

  As described above, in Example 1 bonded using the low melting point curable metal adhesive, the die shear strength was higher than those in Comparative Examples 1 and 2, and a significant effect was also obtained in the drop test. From this, it was confirmed that the mount strength was improved (improved) by using the low melting point curable metal adhesive.

Subsequently, the semiconductor laser device that passed the drop test (semiconductor laser device in which the heat sink was not peeled off) was used in Example 1, Comparative Example 1, 20 each, and Comparative Example 2, 14 in an atmosphere of 75 ° C. The continuous energization test was carried out at CW 20 mW. In this continuous current test, the I _op of 12 hours after the energization as the initial I _op, was defined as the element lifetime where the 1.3I _op. Then, an element that has not reached the element lifetime at the time of 1000 hours is extrapolated to a change in I _op of 900 hours and 1000 hours to predict 1.3 I _op , and an MTTF (Mean Time To Failure) is obtained. .

FIG. 9 is a graph showing I _op travel data of Example 1 and Comparative Examples 1 and 2. 9A shows the I _op travel data of Example 1, FIG. 9B shows the I _op travel data of Comparative Example 1, and FIG. 9C shows the I _op travel data of Comparative Example 2. _Op driving data is shown. As shown in FIG. 9, in Example 1 (see FIG. 9A) and Comparative Example 1 (see FIG. 9B), stable running is shown, but in Comparative Example 2 (see FIG. 9C), I _op running data. The wandering is seen. Further, specific MTTFs were 11,460 hours in Example 1, 11,222 hours in Comparative Example 1, and 5 elements deteriorated within 400 hours in Comparative Example 2, and the energization test was stopped in 500 hours. That is, Example 1 and Comparative Example 1 showed the same characteristics, and Comparative Example 2 resulted in a decrease in characteristics compared to Example 1 and Comparative Example 1.

  The reason why the MTTF was shortened in Comparative Example 2 is considered to be that gas was emitted from the Ag paste containing the epoxy resin during energization and adhered to the end face of the semiconductor laser chip, thereby deteriorating the element. In other words, in Example 1, since the element deterioration due to the generation of the organic gas did not occur, it is considered that the MTTF was longer than that in Comparative Example 2.

  From the above, it was confirmed that in Example 1 bonded using a low-melting point curable metal adhesive, the deterioration of the element characteristics was suppressed and the element life was prolonged.

(Second Embodiment)
FIG. 10 is a perspective view of a semiconductor laser device according to the second embodiment of the present invention. Next, with reference to FIG. 10, a semiconductor laser device according to a second embodiment of the invention will be described. In FIG. 10, corresponding components are denoted by the same reference numerals, and redundant description is omitted.

  In the semiconductor laser device according to the second embodiment, as shown in FIG. 10, the semiconductor laser chip 100 is directly fixed to the block portion 350 of the stem 300 without using a heat sink. In the second embodiment, the semiconductor laser chip 100 is directly bonded to the stem 300 by the low melting point curable metal adhesive 600 (adhesive layer 620).

  Also in the semiconductor laser device according to the second embodiment configured as described above, the mount strength can be improved as in the first embodiment. In addition, deterioration of the semiconductor laser chip 100 can be suppressed and the device life can be extended.

(Third embodiment)
FIG. 11 is a perspective view of a semiconductor laser device according to a third embodiment of the present invention. 12 and 13 are side views for explaining a semiconductor laser device according to a third embodiment of the present invention. Next, a semiconductor laser device according to a third embodiment of the invention will be described with reference to FIGS. In addition, in each figure, the same code | symbol is attached | subjected to a corresponding component, and the overlapping description is abbreviate | omitted.

  As shown in FIGS. 11 to 13, the semiconductor laser device according to the third embodiment further includes a monitoring photodiode 700 for detecting light from the semiconductor laser chip 100 in the configuration of the first embodiment. Yes. The photodiode 700 is an example of the “light receiving element” in the present invention.

  In the third embodiment, the photodiode 700 is bonded to the stem 300 with a low melting point curable metal adhesive 600 (adhesive layer 630).

  Also in the semiconductor laser device according to the third embodiment configured as described above, the mount strength can be improved as in the first embodiment. In addition, deterioration of the semiconductor laser chip 100 can be suppressed and the device life can be extended.

  In the third embodiment, by fixing the photodiode 700 with the low melting point curable metal adhesive 600, the adhesive strength of the photodiode 700 can also be improved. Thereby, the reliability can be further improved.

Further, a semiconductor laser device similar to that of the third embodiment was manufactured, and an experiment similar to that of the first embodiment was performed. The comparative example includes a semiconductor laser device in which a photodiode is fixed to a stem using a metal solder foil made of Au _0.7 Sn _0.3 and having a thickness of 50 μm instead of a low melting point curing metal adhesive, and a low melting point curing metal adhesive. Instead of this, a semiconductor laser device in which a photodiode was fixed to a stem using Ag paste was used. As a result, the same result as in the first embodiment (the same result as in Example 1) was obtained.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the first to third embodiments, an example using a low melting point curable metal adhesive containing Ag particles as metal particles is shown. However, the present invention is not limited to this, and the metal particles are other than Ag. For example, it may be made of Au, Pt, Pd, or the like.

  In the first to third embodiments, the configuration of the semiconductor laser chip to be mounted can be changed as appropriate.

In the first and third embodiments, the example in which the AuSn solder made of Au _0.7 Sn _0.3 is used for bonding the semiconductor laser chip and the heat sink is shown. However, the present invention is not limited to this, and other than AuSn solder. Solder (for example, SnAgCu solder) can also be used. Further, when AuSn solder is used for bonding the semiconductor laser chip and the heat sink, the ratio of Au to Sn may be other than Au _0.7 Sn _0.3 described above.

  In the first and third embodiments, an example using a heat sink made of AlN has been shown. However, the present invention is not limited to this, and a heat sink made of an insulating material other than AlN may be used. Examples of materials other than AlN include SiC, Si, GaAs, and diamond. These materials may be any of single crystal, polycrystal, and amorphous.

  In the first and third embodiments, the example in which AuSn solder is used for bonding the semiconductor laser chip and the heat sink has been described. However, the present invention is not limited to this, and the bonding of the semiconductor laser chip and the heat sink is low. A melting point curable metal adhesive may be used. In the bonding of the semiconductor laser chip and the heat sink and the heat sink and the stem, it is preferable to use at least one of a low melting point curable metal adhesive.

  In the second embodiment, a monitoring photodiode that detects light from the conductor laser chip may be further provided.

10 n-type GaN substrate 20 laminate 21 n-type nitride-based semiconductor layer 22 light-emitting layer (active layer)
23 p-type nitride-based semiconductor layer 24 ridge portion 25 buried layer 26 p-side electrode 27 n-side electrode 28 metal multilayer film 50, 51, 52 lead pin 70 metal wire 100 semiconductor laser chip 200 heat sink 210, 220 metal multilayer film 300 stem (Support base)
350 block (support base)
400 Cap 510 Solder layer 600 Low melting point curable metal adhesive (low temperature curable metal adhesive)
610, 620, 630 Adhesive layer 700 Photodiode (light receiving element)

Claims (10)

A semiconductor laser chip made of a nitride compound semiconductor;
A support base for supporting the semiconductor laser chip,
The semiconductor laser chip is attached to the support substrate by an adhesive;
The adhesive is one in which metal particles covered with a protective film float in an organic solvent at room temperature,
The organic matter is vaporized by heating ,
The protective film is removed by heating ,
The temperature at which the organic substance vaporizes is 200 ° C. or less,
The temperature at which the protective film decomposes is 250 ° C. or higher . A heat sink on which the semiconductor laser chip is mounted;
2. The semiconductor laser device according to claim 1, wherein at least one of the adhesives is used for bonding the semiconductor laser chip and the heat sink, and the heat sink and a supporting base.   The semiconductor laser device according to claim 1, wherein the semiconductor laser chip is directly bonded to the support base with the adhesive. A light-receiving element for monitoring that detects light from the semiconductor laser chip;
4. The semiconductor laser device according to claim 1, wherein the light receiving element is bonded to the support base with the adhesive.   The semiconductor laser device according to claim 1, wherein the adhesive is an adhesive that does not include an epoxy resin in an adhesive layer before curing.   The semiconductor laser device according to claim 1, wherein the metal material constituting the adhesive includes at least one of gold, silver, platinum, and palladium.   The semiconductor laser device according to claim 1, wherein the adhesive includes metal particles having a diameter of 10 μm or less, and is bonded by bonding the metal particles during curing. .   The semiconductor laser device according to claim 1, wherein the semiconductor laser chip is hermetically sealed.   The semiconductor laser device according to claim 1, wherein an oscillation wavelength of the semiconductor laser chip is 600 nm or less. Preparing a support substrate provided with lead pins;
A step of attaching a semiconductor laser chip made of a nitride compound semiconductor to the support substrate using an adhesive;
Performing a wire bond to electrically connect the semiconductor laser chip and the lead pin provided on the support base;
A step of hermetically sealing the semiconductor laser chip by attaching a cap to the support base;
Baking the support base and the cap at a temperature of 250 ° C. or more after the wire bonding and before the hermetic sealing,
The adhesive is one in which metal particles covered with a protective film float in an organic solvent at room temperature,
The organic matter is vaporized by heating ,
The protective film is removed by heating ,
The temperature at which the organic substance vaporizes is 200 ° C. or less,
The method for manufacturing a semiconductor laser device, wherein a temperature at which the protective film decomposes is 250 ° C. or higher .

Images