JP2004096062A - Semiconductor light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an inexpensive semiconductor light emitting device in which the heat generated from a semiconductor light emitting element can be dissipated well and the light emitting point can be prevented from being varied over aging. <P>SOLUTION: In a semiconductor light emitting device where a nitride based semiconductor light emitting element 1 is mounted in a chip state on a heat dissipation block 3 made of Cu or a Cu alloy through a submount 2, the submount 2 is formed of 200-400 μm thick using a material having a thermal expansion coefficient of 3.5-6.0×10<SP>-6</SP>/°C. The semiconductor light emitting element 1 is bonded to the subsmount 2 with the junction down by dividing an AuSn eutectic point solder 7 into a plurality of parts in the bonding face. Furthermore, a groove 12 for dividing the solder 7 is made beneath the light emitting part of the semiconductor light emitting element 1. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor light emitting device, and more particularly to a semiconductor light emitting device in which a semiconductor light emitting element in a chip state is mounted on a heat dissipation block via a submount.
[0002]
[Prior art]
Conventionally, for example, as shown in Non-Patent Document 1, a nitride-based compound semiconductor laser that emits a laser beam having a wavelength near 400 nm has been provided.
[0003]
As one of structures for mounting a semiconductor light emitting device such as a nitride-based compound semiconductor laser, as shown in Patent Document 1 and Patent Document 2, for example, a semiconductor light emitting device in a chip state is bonded to a submount with solder or the like. Further, a structure is known in which this submount is bonded to a heat dissipation block (carrier, stem, etc.).
[0004]
Further, in Patent Document 3, in a structure in which a nitride compound semiconductor light-emitting device generating a large amount of heat is bonded to a support such as a submount, an insulating material is used instead of an insulating material in order to improve heat dissipation from the device. Also disclosed is a method in which a support is formed of a metallic material having high thermal conductivity, and a semiconductor light emitting element is bonded to the support with a junction-down (face-down) structure.
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-346029
[Patent Document 2]
JP-A-5-299699 [0007]
[Patent Document 3]
Japanese Patent Laid-Open No. 9-223846
[Non-Patent Document 1]
Japanese Applied Physics Letters, Vol. 37, (1998), p. L1020
[0009]
[Problems to be solved by the invention]
In the case of adopting the above mounting structure, there is a problem that the element is deteriorated due to thermal strain at the time of solder bonding. Therefore, conventionally, as described in Patent Document 1, a material having a small difference in thermal expansion coefficient is selected and used as a material for the submount and the heat dissipation block, and stress due to thermal strain at the time of soldering them together There has been proposed a structure in which it is difficult to transmit to the semiconductor light emitting device.
[0010]
Further, as described in Patent Document 2, by selecting and using a material having a small difference in thermal expansion coefficient from that of the semiconductor light emitting element as a material for the submount, a large stress is caused by thermal strain when the two are soldered together. A structure has been proposed in which is prevented from acting on the semiconductor light emitting device.
[0011]
By the way, the electro-optical conversion efficiency of a semiconductor laser that oscillates in a red to infrared wavelength region is about 40 to 50%, whereas that of a nitride-based compound semiconductor laser is generally as low as about 15% or less. Is also quite large. Therefore, when mounting this nitride-based compound semiconductor laser with a structure as described in Patent Document 3, it is necessary to form the submount and the heat dissipation block from a material having high thermal conductivity. As described above, CuW is mentioned as a material having a high thermal conductivity and a small difference in thermal expansion coefficient from that of a nitride-based compound semiconductor material. However, since this CuW is not good in workability, the submount and heat dissipation formed therewith are not good. Blocks become expensive.
[0012]
A technique for suppressing the generation of strain by setting the thickness of the submount to be large is also known, but in such a case, the thermal conductivity is lowered, so that the characteristics of the semiconductor laser element are easily deteriorated.
[0013]
On the other hand, it is also considered to use a low-melting-point solder as solder for bonding the semiconductor light emitting element in a chip state and the submount or the submount to the heat dissipation block to prevent the element deterioration due to the thermal strain. However, when such a low melting point solder is used, the light emitting point position of the semiconductor light emitting element may fluctuate with time, and in particular, the light beams from a plurality of semiconductor light emitting elements are coupled to, for example, a multiplexing optical system. In such a configuration, the coupling efficiency may decrease due to the temporal variation of the light emitting point position.
[0014]
The present invention has been made in view of the above circumstances, and can efficiently dissipate heat generated by a semiconductor light-emitting element, can prevent variation with time of a light-emitting point position, and can be manufactured at low cost. An object is to provide an apparatus.
[0015]
[Means for Solving the Problems]
A semiconductor light-emitting device according to the present invention comprises:
In a semiconductor light emitting device in which a nitride compound semiconductor light emitting element in a chip state is mounted on a heat dissipation block made of Cu (copper) or Cu alloy via a submount,
The submount is formed to a thickness of 200 to 400 μm using a material having a thermal expansion coefficient (linear expansion coefficient) of 3.5 to 6.0 × 10 ⁻⁶ / ° C.,
The semiconductor light-emitting element is divided and bonded to the submount in a junction-down structure with a solder composed mainly of AuSn, which is divided into a plurality of parts within the bonding surface of both.
A groove for dividing the solder exists at least immediately below the light emitting portion of the semiconductor light emitting element.
[0016]
The junction down structure is a structure in which the element formation surface side (pn junction side) is fixed to a heat dissipation mount having a high thermal conductivity, not the substrate side, as described in Patent Document 3. is there.
[0017]
Further, when a metallized layer for solder bonding or the like is formed on one side or both sides of the solder layer containing AuSn as a main component, the metallized layer is preferably divided into a plurality of layers together with the solder.
[0018]
Here, the solder layer mainly composed of AuSn is formed to be smaller than the electrode of the nitride-based compound semiconductor light-emitting element and to have a thickness of about 1 to 3 μm, and has a composition due to an alloy reaction during bonding. It is desirable for the melting point to change.
[0019]
The submount is preferably made of SiC or AlN.
[0020]
In the semiconductor light emitting device of the present invention, it is desirable that the submount and the Cu or Cu alloy heat dissipating block are also bonded by solder containing AuSn as a main component.
[0021]
Furthermore, the present invention is preferably applied to a semiconductor light-emitting device using a nitride-based compound semiconductor light-emitting element having a light-emitting portion protruding in a ridge shape on the submount side.
[0022]
【The invention's effect】
Since the semiconductor light emitting device of the present invention uses a heat dissipation block formed of Cu or Cu alloy with low cost and high thermal conductivity, it can dissipate the heat generated by the semiconductor light emitting element satisfactorily and at low cost. It can be produced.
[0023]
The semiconductor light-emitting device of the present invention has a light-emitting portion of the semiconductor light-emitting element as compared with the case where the substrate side of the semiconductor light-emitting element is fixed to the submount by fixing the semiconductor light-emitting element to the submount with a junction down structure. Is located closer to the submount, and thus closer to the heat dissipation block, the heat can be well radiated from this point.
[0024]
Also, since the solder containing AuSn as a main component has excellent temporal position change characteristics, the semiconductor light-emitting device of the present invention in which the semiconductor light-emitting element and the submount are bonded to each other has a time-dependent emission point position of the semiconductor light-emitting element. Fluctuations can be effectively suppressed. In particular, when the heat sink block made of Cu or Cu alloy and the submount are also bonded by the solder having AuSn as a main component, the above-described effect becomes higher.
[0025]
Furthermore, in the semiconductor light emitting device of the present invention, the submount is formed to a thickness of 200 to 400 μm using a material having a thermal expansion coefficient of 3.5 to 6.0 × 10 ⁻⁶ / ° C. It is also possible to prevent the semiconductor light emitting element from deteriorating due to thermal strain during solder bonding. The reason will be described in detail along the embodiment of the present invention described later.
[0026]
Note that the solder containing AuSn as a main component can suppress the temporal variation of the light emitting point position as described above. On the other hand, the thermal expansion coefficient is relatively large as 18 × 10 ⁻⁶ / ° C. When a semiconductor light emitting device is mounted on the submount having the above-described coefficient using the solder, the device may be damaged by thermal strain. However, in the semiconductor light emitting device of the present invention, the solder mainly composed of AuSn is divided into a plurality of parts within the bonding surface between the submount and the semiconductor light emitting element, so that the stress generated at the bonding portion is reduced. It can also be suppressed.
[0027]
In addition, since the groove for dividing the solder exists directly under the light emitting portion of the semiconductor light emitting element, the light emitting portion is not directly bonded to the submount, and therefore the effect of reducing the stress is further enhanced. It will be a thing.
[0028]
In particular, when the light emitting part has a shape protruding to the submount side, the protruding light emitting part interferes with the solder or the metallized layer because the groove exists immediately below the light emitting part. This makes it easy to implement. In the case where an electrode layer is formed on the surface of the semiconductor light emitting device that is bonded to the submount, and this electrode layer is formed so as to cover the surface of the light emitting portion, of course, the light emitting portion including this electrode layer is also included. It is assumed that the groove is present immediately below.
[0029]
Here, if a structure in which the light emitting portion is not directly bonded to the submount as described above is adopted, heat dissipation may be impaired as compared with the case where the light emitting portion is directly bonded to the submount. However, if the solder layer mainly composed of AuSn is formed to be smaller than the electrode of the semiconductor light-emitting element and the thickness is reduced to about 1 to 3 μm, the position shift of the semiconductor light-emitting element at the time of mounting is reduced, so that mounting is possible. Since the positional accuracy can be controlled with a high accuracy of about ± 1 μm, the groove is made as narrow as possible to ensure a larger contact area between the semiconductor light emitting element and the submount so that there is almost no decrease in heat dissipation. be able to.
[0030]
In particular, when using a solder whose main component is AuSn and whose melting point changes due to an alloy reaction during bonding, after bonding the semiconductor light emitting element to the submount, the submount is attached to the heat dissipation block. It is possible to prevent the solder bonding the semiconductor light emitting element and the submount from being melted when bonded to each other.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0032]
FIG. 1 shows a front shape of a semiconductor light emitting device 10 according to an embodiment of the present invention. As shown in the figure, the semiconductor light emitting device 10 includes a nitride compound semiconductor laser device 1 such as a GaN semiconductor laser device mounted in a chip state on a Cu heat dissipation block 3 via an AlN submount 2. Is.
[0033]
This implementation is done in detail as follows. First, as shown in FIG. 2, an Au / Pt / Ti metallized layer 4 is formed on the lower surface of the AlN submount 2, and an Au / Pt / Ti metallized layer 5 as an electrode wiring functional layer is formed on the upper surface thereof. An Au / Pt / Ti metallized layer 6 having steps as a wettability improving layer and a height adjusting layer is formed. Here, the thickness of the submount referred to in the present invention is a thickness that does not include each of the layers 4 to 6, that is, the dimension d in FIG.
[0034]
As described above, the Au / Pt / Ti metallized layer 6 having a step is formed by, for example, uniformly forming the metallized layer 6 thickly, and then removing the lowered portion by a dry process such as ion milling or a wet process using an etchant. It can be formed by applying a method, or a method of metallizing by the height of the lower layer and then metallizing again after masking the lowering portion.
[0035]
Next, pad-like eutectic point AuSn solders 7 and 7 are disposed on the high and low portions of the Au / Pt / Ti metallized layer 6, respectively. These pad-like eutectic point AuSn solders 7 and 7 are formed to have a size of 150 × 500 μm, for example, and are arranged at an interval of 10 μm, for example. Then, on these eutectic point AuSn solders 7 and 7, as an example, a chip-like nitride compound semiconductor laser element 1 having a size of approximately 400 × 600 × 100 μm and having electrode layers 1a and 1b formed on the surface is provided. The nitride compound semiconductor laser element 1 is bonded and fixed to the AlN submount 2 from the electrode layers 1a and 1b side by disposing and heating to 330 ° C. to melt the eutectic point AuSn solders 7 and 7.
[0036]
Next, an eutectic point AuSn solder 11 is placed on the Cu heat dissipation block 3 on which the Au / Ni plating layer 8 and the Au / Pt / Ti metallization layer 9 as the wetting improvement layer are formed on the upper surface, and on it. The AlN submount 2 is arranged with the Au / Pt / Ti metallized layer 4 down, and the eutectic point AuSn solder 11 is melted by heating to 310 ° C., whereby the AlN submount 2 is bonded and fixed to the Cu heat dissipation block 3. To do. As described above, the nitride-based compound semiconductor laser device 1 is mounted on the Cu heat dissipation block 3 via the AlN submount 2.
[0037]
The melting point of AuSn solder changes according to the composition ratio of Au and Sn. Therefore, by controlling the film thicknesses of the Au / Pt / Ti metallized layers 6 and 4 of the AlN submount 2 independently of each other and controlling the temperature at which the eutectic point AuSn solders 7 and 11 are melted, By setting each Au composition ratio in the state after the AuSn solder 7 is melted and in the state after the eutectic point AuSn solder 11 is melted to a composition higher by several percent than the eutectic point composition, the eutectic point AuSn solder 7 and A difference can be made in the melting point of 11 after melting.
[0038]
By causing such a melting point difference, the same eutectic point AuSn is used when the nitride compound semiconductor laser device 1 is bonded to the AlN submount 2 and when the AlN submount 2 is bonded to the Cu heat dissipation block 3. Even if the solder is used, if the melting temperature difference is given to each other, the eutectic point AuSn solder 7 can be mounted without melting at the time of the latter bonding (lower in the latter bonding). If this is the case, it is not necessary to use a low melting point solder whose light emission point position is likely to change over time, which is advantageous in suppressing fluctuations in the light emission point position.
[0039]
Further, in the present embodiment, the nitride-based compound semiconductor laser device 1 is arranged in such a direction that the substrate side made of Al ₂ O ₃ is positioned upward, and the device formation surface side (pn junction side) is fixed to the Cu heat dissipation block 3. The so-called junction down structure is used for mounting.
[0040]
Further, in this structure, the light emitting point of the nitride-based compound semiconductor laser element 1 is in a ridge portion that protrudes toward the AlN submount 2 as indicated by Q in FIG. The eutectic point AuSn solder 7, the Au / Pt / Ti metallized layer 6 and the Au / Pt / Ti metallized layer 5 are formed with grooves 12 for dividing them, and the nitride-based compound semiconductor laser device 1 has its light emitting portion. The groove 12 is bonded so that the groove 12 is located immediately below. That is, since the light emitting portion of the nitride-based compound semiconductor laser element 1 is not directly bonded to the submount side, further stress reduction is realized. Further, if the groove 12 is formed, even when the light emitting end face of the nitride-based compound semiconductor laser element 1 (which is an end face parallel to the paper surface of FIG. 1) is located inside the end face of the AlN submount 2, It is possible to prevent the luminescence beam from being vignetted by the AlN submount 2.
[0041]
The n-side electrode of the nitride-based compound semiconductor laser device 1 is formed at a position facing the high portion of the Au / Pt / Ti metallized layer 6 and the high and low portions of the Au / Pt / Ti metallized layer 6 May be formed so as to be insulated from each other, and the n-side electrode and the p-side electrode may be electrically connected to both of these parts, respectively.
[0042]
The metallized layers 4, 6 and 9 other than the Au / Pt / Ti metallized layer 5 having an electrode wiring function may be formed of Pt / Ti instead of Au / Pt / Ti.
[0043]
Since the semiconductor light emitting device 10 of the present embodiment uses the heat dissipation block 3 formed of Cu with low cost and high thermal conductivity, the heat generated by the nitride-based compound semiconductor laser element 1 can be radiated well. Can be manufactured at low cost.
[0044]
Further, in the semiconductor light emitting device 10 of the present embodiment, the nitride compound semiconductor laser element 1 is fixed to the AlN submount 2 with a junction down structure, so that the nitride compound semiconductor laser element 1 is on the substrate side. Since the light emitting portion of the element 1 is located closer to the submount 2 and thus closer to the heat radiating block 3 than in the case of fixing to the AlN submount 2, heat can be radiated well from this point. It becomes.
[0045]
In addition, since the AuSn eutectic point solder 7 is excellent in position change characteristics with time, the semiconductor light emitting device 10 of the present embodiment in which the nitride compound semiconductor laser element 1 and the AlN submount 2 are bonded together is It is possible to effectively prevent the temporal variation of the light emitting point position of the nitride-based compound semiconductor laser device 1. In the present embodiment, in particular, since the Cu heat dissipation block 3 and the AlN submount 2 are also bonded by the AuSn eutectic point solder 11, the above-described effect becomes higher.
[0046]
Since the AuSn eutectic point solder 7 has a relatively large thermal expansion coefficient of 18 × 10 ⁻⁶ / ° C., the AlN submount 2 having a thermal expansion coefficient of 4.5 × 10 ⁻⁶ / ° C. as described later is applied to the AlN submount 2. When the nitride-based compound semiconductor laser device 1 is mounted using the solder 7, the device 1 may be damaged by thermal strain. However, in the semiconductor light emitting device 10 according to the present embodiment, the eutectic point AuSn solder 7 and the Au / Pt / Ti metallized layers 5 and 6 are divided into a plurality of portions within the bonding surface of the both by the grooves 12. It is also possible to reduce the stress generated at the bonded portion.
[0047]
In addition, since the groove 12 is present directly under the light emitting portion, the light emitting portion is not directly bonded to the AlN submount 2, and therefore the effect of reducing the stress is further enhanced.
[0048]
Further, in the present embodiment, the ridge portion Q including the light emitting portion is in a state of protruding to the AlN submount 2 side. However, the groove 12 protrudes because the groove 12 exists immediately below the light emitting portion. Since the light emitting portion is prevented from interfering with the eutectic point AuSn solder 7 and the Au / Pt / Ti metallized layers 5 and 6, mounting is also facilitated.
[0049]
Here, if a structure in which the light emitting part is not directly bonded to the AlN submount 2 as described above is adopted, the heat dissipation may be impaired as compared with the case where the light emitting part is directly bonded to the submount. However, if the layer of the eutectic point AuSn solder 7 is formed to be smaller than the electrode layers 1a and 1b of the nitride compound semiconductor laser element 1 and to have a thickness as thin as about 1 to 3 μm, the nitride compound at the time of mounting is used. Since the positional deviation of the semiconductor laser device 1 is reduced, the mounting position accuracy can be controlled with a high accuracy of about ± 1 μm. Therefore, the groove 12 is made as narrow as possible to reduce the contact area between the device 1 and the AlN submount 2. It is possible to ensure a larger value so that there is almost no decrease in heat dissipation.
[0050]
FIG. 3A shows the result of measuring the amount of vertical movement of the light emitting point position when the semiconductor light emitting device 10 of the present embodiment is subjected to a time-lapse test under the condition of −40 to 80 ° C. Note that the horizontal axis of the figure shows a normal probability distribution (%) of the amount of movement of the light emitting point by the solder material, and the vertical axis shows the amount of movement of the light emitting point position. In addition, the amount of movement of the light emitting point position when a low melting point solder is used instead of the AuSn eutectic point solder 7 is indicated by b in FIG. As shown here, in the semiconductor light emitting device 10 of the present embodiment, the amount of movement of the light emitting point position is suppressed to be extremely small as compared with that using low melting point solder.
[0051]
Next, FIG. 4 shows which stress acting on the light emitting point of the nitride-based compound semiconductor laser element 1 due to thermal strain when the semiconductor light emitting device 10 of the present embodiment is mounted depends on the thermal expansion coefficient of the submount. It shows the result obtained by the simulation by the computer. In this simulation, in addition to the AlN submount 2, the Cu heat dissipation block 3, the Au / Pt / Ti metallized layers 4, 5, 6 and 9, the Au / Ni plating layer 8, the eutectic point AuSn solders 7 and 11, nitriding Obtain the thickness, thermal expansion coefficient (excluding the thermal expansion coefficient of the AlN submount 2) and Young's modulus for all of the substrate, lower cladding layer, light emitting layer, upper light emitting layer, and insulating film of the physical compound semiconductor laser element 1, Those numbers were used.
[0052]
As shown in FIG. 4, when the thermal expansion coefficient of the submount is in the range of 3.5 to 6.0 × 10 ⁻⁶ / ° C., the stress is about 32 MPa or less, and the nitride-based compound semiconductor laser device 1 is In practical use, it can be suppressed to a range where there is no particular problem. In view of this point, in the present invention, the submount is formed from a material having a thermal expansion coefficient in the range of 3.5 to 6.0 × 10 ⁻⁶ / ° C.
[0053]
Further, if the thermal expansion coefficient of the submount is in the range of 4.0 to 5.4 × 10 ⁻⁶ / ° C., the stress is more preferably about 29.5 MPa or less, and the thermal expansion coefficient of the submount is 4 If it is in the range of .4 to 4.8.times.10.sup.- ⁶ / .degree. C., the stress is approximately 28 MPa, which is more preferable. The thermal expansion coefficient of AlN used for the submount in the present embodiment is 4.5 × 10 ⁻⁶ / ° C., which is in the most preferable range.
[0054]
The thermal expansion coefficient of Cu, which is the material of the heat dissipation block 3, is 17 × 10 ⁻⁶ / ° C., whereas the thermal expansion coefficient of GaN, which is the substrate material of the nitride-based compound semiconductor laser element 1, is 5.6. Since it is as small as × 10 ⁻⁶ / ° C., if it is directly mounted on the Cu heat dissipation block 3, a large thermal strain is generated due to a difference in thermal expansion, and the device characteristics are remarkably deteriorated. Therefore, without such direct mounting, a nitride compound semiconductor laser is formed on the submount 2 made of AlN having a thermal expansion coefficient of 4.5 × 10 ⁻⁶ / ° C. close to that of GaN and having a thickness as described later. By fixing the element 1 and fixing the AlN submount 2 to the Cu heat dissipating block 3, it is possible to prevent deterioration of the characteristics of the element 1.
[0055]
Further, FIG. 5 shows that the stress acting on the light emitting point of the nitride-based compound semiconductor laser element 1 due to thermal strain when the semiconductor light emitting device 10 of the present embodiment is mounted depends on the thickness of the AlN submount 2. It shows the result obtained by the simulation by the computer in the same way how it changes. In this simulation, in addition to the AlN submount 2, the Cu heat dissipation block 3, the Au / Pt / Ti metallization layers 4, 5, 6 and 9, the Au / Ni plating layer 8, the eutectic point AuSn solders 7 and 11, nitriding Thickness, thermal expansion coefficient, and Young's modulus were determined for all of the substrate, lower clad layer, light emitting layer, upper light emitting layer, and insulating film of the physical compound semiconductor laser device 1, and these numerical values were used.
[0056]
As shown in FIG. 5, when the thickness of the AlN submount 2 is in the range of 200 to 400 μm, the stress is about 34 MPa or less, and there is no particular problem when the nitride-based compound semiconductor laser device 1 is actually used. Limited to range. When stress exceeding this value acts on the AlN submount 2, stress is likely to be generated there. In view of this point, in the present invention, the thickness of the submount is set in the range of 200 to 400 μm. Further, if the thickness of the AlN submount 2 is in the range of 250 to 350 μm, the stress is more preferably about 32 MPa or less.
[0057]
The AlN submount 2 receives a large compressive stress from the Cu heat dissipation block 3. The AlN submount 2 is also subjected to compressive stress from the nitride-based compound semiconductor laser element 1, which is generally smaller than the compressive stress received from the Cu heat dissipation block 3.
[0058]
In addition, the AlN submount 2 to which the nitride-based compound semiconductor laser device 1 is bonded as described above is arranged in a row on the Cu heat dissipation block 3 and bonded to form a plurality of nitride-based compound semiconductor laser devices. It is also possible to form an array laser device in which 1 are juxtaposed. FIG. 6 shows an example in which nine nitride compound semiconductor laser elements 1 are arranged in parallel as an example of such an array laser apparatus.
[0059]
In such an array laser apparatus, in a configuration in which the light beam emitted from each nitride-based compound semiconductor laser element 1 is coupled to, for example, a multiplexing optical system, if there is a temporal variation in the light emitting point position, As a result, the coupling efficiency decreases. Therefore, if the configuration of the present invention that can suppress the temporal variation of the light emitting point position as described above is applied to this type of array laser device, it is possible to prevent the coupling efficiency from being lowered.
[0060]
The present invention is not limited to the case of using a nitride-based compound semiconductor laser as the nitride-based compound semiconductor light-emitting device, but is similarly applied to the case of using other nitride-based compound semiconductor light-emitting devices including a light emitting diode (LED). Is possible. Furthermore, instead of the above-described heat radiation block 3 made of only copper, a heat radiation block made of tellurium copper or the like may be employed.
[Brief description of the drawings]
FIG. 1 is a front view showing a semiconductor light emitting device according to an embodiment of the present invention. FIG. 2 is a perspective view showing a part of the semiconductor light emitting device. FIG. 4 is a graph showing the relationship between the thermal expansion coefficient of a submount in the semiconductor light emitting device and the stress acting on the light emitting point. FIG. FIG. 6 is a front view showing an example of an array laser device according to the present invention. FIG. 6 is a front view showing a relationship between the thickness of a submount in a light emitting device and stress acting on a light emitting point.
DESCRIPTION OF SYMBOLS 1 Nitride compound semiconductor laser element 2 AlN submount 3 Cu heat dissipation block 4, 5, 6, 9 Au / Pt / Ti metallized layer 8 Au / Ni plating layer 7, 11 Eutectic point AuSn solder 10 Semiconductor light emitting device

Claims (5)

In a semiconductor light emitting device in which a nitride compound semiconductor light emitting element in a chip state is mounted on a heat dissipation block made of Cu or Cu alloy via a submount,
The submount is formed to a thickness of 200 to 400 μm using a material having a thermal expansion coefficient of 3.5 to 6.0 × 10 ⁻⁶ / ° C .;
The semiconductor light-emitting element is divided and bonded to the submount in a junction-down structure with a solder composed mainly of AuSn, which is divided into a plurality of parts within the bonding surface of both.
A semiconductor light emitting device characterized in that a groove for dividing the solder exists at least immediately below a light emitting portion of the semiconductor light emitting element. The solder layer mainly composed of AuSn is smaller than the electrode of the nitride-based compound semiconductor light emitting device and is formed to a thickness of 1 to 3 μm.
2. The semiconductor light emitting device according to claim 1, wherein the melting point is changed by changing the composition due to an alloy reaction during bonding. 3. The semiconductor light emitting device according to claim 1, wherein the submount is made of SiC or AlN. 4. The semiconductor light emitting device according to claim 1, wherein the submount is bonded to the Cu or Cu alloy heat dissipation block with solder containing AuSn as a main component. 5. 5. The semiconductor light emitting device according to claim 1, wherein a light emitting portion of the nitride-based compound semiconductor light emitting element has a shape protruding in a ridge shape on the submount side.

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