JP7536607B2 - Semiconductor laser device and method for manufacturing the same - Google Patents

Description

This application relates to a semiconductor laser device and a method for manufacturing a semiconductor laser device.

Conventionally, in order to efficiently dissipate heat generated in a semiconductor laser device and ensure its characteristics, a semiconductor laser device has been disclosed in which an electrode closer to an active layer, which is a heat source of the semiconductor laser device, is bonded to a submount.
That is, the conventional semiconductor laser device has a semiconductor laser element having a substrate, an n-type cladding layer, an active layer, a p-type cladding layer, a p-type contact layer, and a p-side electrode, which are sequentially stacked on one surface of the substrate, and an n-type electrode formed on the other surface of the substrate. The distance from the active layer to the p-type electrode is shorter than the distance from the active layer to the n-type electrode, and the p-type electrode is bonded to a submount. The submount is bonded to a first heat sink on the surface opposite to the semiconductor laser element. In this way, by fixing the active layer, which is a heat source, to the submount so that it is located close to the submount, heat generated in the active layer is transferred to the submount and the first heat sink (see, for example, Patent Document 1).

JP 2019-62033 A (paragraphs [0038] to [0089], Figures 1 to 7)

In such a semiconductor laser device, the electrode close to the active layer is bonded to the submount, so that the heat from the active layer is efficiently transferred to the submount and the first heat sink to dissipate the heat. However, since the electrode close to the active layer is bonded to the submount in this way, for example, when mounting the semiconductor laser element, stress such as thermal stress caused by the difference between the thermal expansion coefficient of the adhesive material such as solder used for bonding to the submount and the thermal expansion coefficient of the semiconductor laser element material is easily applied to the active layer. As a result, there is a problem that distortion occurs in the active layer, causing wavelength jumps of the laser light, and performance is deteriorated.
The present application discloses a technique for solving the above-mentioned problems, and has an object to provide a high-performance semiconductor laser device in which high heat dissipation properties are ensured, and a method for manufacturing the semiconductor laser device.

The semiconductor laser device disclosed in the present application comprises:
A semiconductor laser device comprising a laser section that emits laser light and a modulator section that modulates the laser light emitted from the laser section, the laser section and the modulator section being integrated on a submount,
The laser portion includes a first electrode layer that is in contact with a surface of the submount on a first direction side in a thickness direction and is connected to the submount;
a first conductive type semiconductor layer provided on the first direction side of the first electrode layer;
an active layer provided on the first direction side of the first conductive type semiconductor layer;
a second conductive type semiconductor layer provided on the first direction side of the active layer;
a second electrode layer provided on the first direction side of the second conductive type semiconductor layer,
The first conductive type semiconductor layer has a length L1 of 80 μm or more in the thickness direction, and the second conductive type semiconductor layer has a length L2 shorter than the length L1 of the first conductive type semiconductor layer,
a protruding portion protruding from the second electrode layer toward the first direction on the second electrode layer, the protruding portion being spaced apart from a first connection line that supplies a current to the active layer via the second electrode layer;
two grooves recessed from a surface of the second electrode layer on the first direction side toward a second direction opposite to the first direction are formed at a first distance from each other and extend in a third direction perpendicular to the thickness direction;
an insulating layer is formed between the second electrode layer and the second conductive type semiconductor layer, the insulating layer having a first opening portion formed between the groove portions and extending in the third direction;
the protrusion is formed only at a position outside the groove, the position being on the opposite side of the groove from the side on which the first opening is located,
a first mesa stripe portion having a mesa shape in a cross section in the thickness direction, including the first conductive type semiconductor layer and the active layer, and extending in the third direction;
the first mesa stripe portion is formed between the groove portions,
the active layer is formed only in the first mesa stripe portion,
buried layers, which are semiconductor layers, are formed between both side surfaces of the first mesa stripe portion along the third direction and both side surfaces of the active layer along the third direction, the buried layers being in contact with both side surfaces of the active layer and extending in the third direction;
the buried layer is formed continuously from both side surfaces of the active layer to a position on the second direction side of the protruding portion outside the groove portion.
It is something.
The present invention also discloses a method for manufacturing a semiconductor laser device, comprising the steps of:
In the method for manufacturing the semiconductor laser device configured as described above,
A wire material is melted by a wire bonding device to wire the first connection line;
The wire is melted by the wire bonding device to form the protrusion.
It is something.

The semiconductor laser device and the method for manufacturing the semiconductor laser device disclosed in this application ensure high heat dissipation and provide a high-performance semiconductor laser device and a method for manufacturing the semiconductor laser device.

1 is a top view showing a schematic configuration of a semiconductor laser device according to a first embodiment. 1 is a cross-sectional view of a semiconductor laser device according to a first embodiment. 1 is a side view of a semiconductor laser device according to a first embodiment; 1 is a top view of a semiconductor laser device according to a first embodiment. 1 is a cross-sectional view of a DFB laser portion of a semiconductor laser element according to a first embodiment. 2 is a cross-sectional view of a waveguide portion of the semiconductor laser element according to the first embodiment. 2 is a cross-sectional view of a modulator portion of the semiconductor laser device according to the first embodiment. 1 is a cross-sectional view of a semiconductor laser device according to a first embodiment. 1 is a cross-sectional view of a semiconductor laser device according to a first embodiment. FIG. 11 is a top view showing a schematic configuration of a semiconductor laser device according to a second embodiment. FIG. 11 is a cross-sectional view of a semiconductor laser device according to a second embodiment. FIG. 11 is a side view of a semiconductor laser device according to a second embodiment. 11 is a schematic top view showing an example of the configuration of a semiconductor laser element according to a second embodiment. FIG. 11 is a schematic top view showing an example of the configuration of a semiconductor laser element according to a second embodiment. FIG. 11 is a schematic top view showing an example of the configuration of a semiconductor laser element according to a second embodiment. FIG. 11 is a schematic top view showing an example of the configuration of a semiconductor laser element according to a second embodiment. FIG. FIG. 11 is a top view showing a schematic configuration of a semiconductor laser device according to a third embodiment. FIG. 11 is a cross-sectional view of a semiconductor laser device according to a third embodiment. FIG. 11 is a side view of a semiconductor laser device according to a third embodiment.

Embodiment 1.
FIG. 1 is a top view showing a schematic configuration of a semiconductor laser device 100 according to the first embodiment.
FIG. 2 is a cross-sectional view of the semiconductor laser device 100 shown in FIG. 1 taken along line AA'.
FIG. 3 is a side view of the semiconductor laser device 100 shown in FIG.
The semiconductor laser device 100 includes a semiconductor laser element C and a submount 1 which is a flat substrate on which the semiconductor laser element C is mounted. The semiconductor laser element C is connected to the submount 1 by using a wire 3 which serves as a first connection line.

In the following description, the thickness direction of the submount 1 shown in FIG. 2 is referred to as the thickness direction Y, one direction of this thickness direction Y is referred to as the upward direction Y1 as a first direction, and the direction opposite to this upward direction Y1 is referred to as the downward direction Y2 as a second direction. In addition, among the directions perpendicular to this thickness direction Y, the horizontal direction in the top view of the semiconductor laser device 100 in FIG. 1 is referred to as the horizontal direction X, and the vertical direction is referred to as the vertical direction Z as a third direction. Other components that make up the semiconductor laser device 100 will also be described using these directions as references.

First, the detailed configuration of the semiconductor laser element C will be described with reference to FIGS.
FIG. 4 is a top view of the semiconductor laser element C before it is mounted on the submount 1. As shown in FIG.
The semiconductor laser element C is an electro-absorption modulator integrated semiconductor laser (EML-LD: Electro-absorption modulator Laser Diode) that includes, integrated together, a distributed feedback type DFB (Distributed Feedback Laser Diode) laser section 10 as a laser section that emits laser light of a single wavelength, and an electro-absorption modulator section 30 that modulates the laser light emitted from the DFB laser section 10.

Between the DFB laser section 10 and the modulator section 30, a waveguide section 20A is formed that guides the laser light emitted from the DFB laser section 10 to the modulator section 30. Furthermore, between the modulator section 30 and the laser light emission port Cout that emits the laser light, a waveguide section 20B is formed that guides the laser light emitted from the modulator section 30.

First, the configuration of the DFB laser section 10 will be described below.
FIG. 5 is a cross-sectional view taken along line DD' of the DFB laser portion 10 of the semiconductor laser device C shown in FIG.

As shown in FIG. 5, the DFB laser unit 10 includes an electrode C10 as a first electrode layer that abuts against the surface (upper surface) of the submount 1 on the upward Y1 side and is electrically connected to the upper surface of the submount 1. The electrode C10 includes an n-type semiconductor substrate C9 (hereinafter referred to as substrate C9) as a first conductive type semiconductor layer provided on the upward Y1 side of the electrode C10, an active layer C8 provided on the upward Y1 side of the substrate C9, a diffraction grating C7 provided on the upward Y1 side of the active layer C8, p-type cladding layers C4-1, C4-2 and a p-type contact layer C3 as second conductive type semiconductor layers provided on the upward Y1 side of the diffraction grating C7, and an electrode C1 as a second electrode layer formed on the upward Y1 side of the p-type cladding layers C4-1, C4-2 and the p-type contact layer C3, and these layers are stacked in the thickness direction Y.

In the substrate C9, a mesa stripe portion Cme, which includes the active layer C8, the diffraction grating C7, and the p-type cladding layer C4-1, and has a mesa-shaped cross section in the thickness direction Y and a width W1 as a first mesa stripe portion, is formed so as to extend in the vertical direction Z perpendicular to the thickness direction Y. Then, a buried layer Cbo, which is a semiconductor layer, is formed so as to bury both side surfaces of the active layer C8, the diffraction grating C7, and the p-type cladding layer C4-1 of this mesa stripe portion Cme. In this embodiment, the buried layer Cbo is formed by covering the n-type block layer C6, which is an n-type semiconductor layer, with the p-type block layer C5, which is a p-type semiconductor layer.

On the surface (top surface) on the upward Y1 side of the electrode C1, two groove portions M recessed from the top surface toward the downward Y2 side are formed extending in the vertical direction Z at a first distance H1 between them so as to sandwich the mesa stripe portion Cme.
An insulating layer C2 is formed between the electrode C1 and the p-type contact layer C3. The insulating layer C2 has an opening Cop as a first opening having a width W1 and extending in the vertical direction Z on the upper direction Y1 side of the active layer C8. As a result, the electrode C1 is joined to the p-type contact layer C3 only at a connection point P2 above the active layer C8, and the electrode C1 is insulated from the p-type contact layer C3 by the insulating layer C2 in other portions.

Here, the length L1 of the n-type semiconductor substrate (substrate C9) on the downward Y2 side of the active layer C8 is formed to ensure a length of 80 μm or more. Also, the length L2 in the thickness direction Y of the p-type semiconductor layer (p-type cladding layers C4-1, C4-2 and p-type contact layer C3) on the upward Y1 side of the active layer C8 is formed to be shorter than the length L1 of the substrate C9. That is, the active layer C8, which serves as a heat source, is disposed in the semiconductor laser element C at a position closer to the electrode C1 on the upward Y1 side than to the electrode C10 on the downward Y2 side of the semiconductor laser element C.

The manufacturing method of the semiconductor laser element C having the above-mentioned configuration includes forming an active layer C8 made of a material such as InGaAsP, AlGaInAs, or GaInAsP on an n-InP substrate C9 having a thickness of 100 μm. Then, a diffraction grating C7 is formed on this active layer C8. Then, a p-InP cladding layer C4-1 is formed on this diffraction grating C7 to embed the diffraction grating C7, thereby forming a semiconductor intermediate laminate.

Then, this semiconductor intermediate laminate is etched by dry etching to a depth of D1, leaving only a region with a width of W1. Then, p-InP/n-InP/p-InP block layers C5 and C6 are formed so as to embed both side surfaces of the active layer C8, diffraction grating C7, and p-InP clad layer C4-1. Next, a p-InP clad layer C4-2 is formed on the p-InP clad layer C4-1 and the p-InP block layer C5, and a p-InGaAs contact layer C3 is formed on the p-InP clad layer C4-2.

After the p-InGaAs contact layer C3 is formed, a groove M is formed by dry etching or wet etching so as to cut in the thickness direction Y up to the n-InP block layer C6. Then, a SiN insulating layer C2 having an opening Cop that opens only above the active layer C8 is formed on the p-InGaAs contact layer C3 and in the groove M. Then, electrodes C1 and C10 are formed by deposition, sputtering, plating, or the like on the upward Y1 side of the SiN insulating layer C2 and the downward Y2 side of the substrate C9.

The above manufacturing method and configuration are just examples. Other possible configurations for the semiconductor laser element C include a structure having an active layer such as GaInNAs on a GaAs substrate, a p-InP/Fe-InP/n-InP/p-InP blocking layer as a blocking layer, or a blocking layer made of a high-resistance semiconductor.

Next, the configuration of the waveguide portions 20A and 20B of the semiconductor laser device C will be described.
Fig. 6 is a cross-sectional view taken along lines EE' and GG' of the waveguide portions 20A and 20B of the semiconductor laser device C shown in Fig. 4. Assuming that the waveguide portions 20A and 20B have the same configuration, only Fig. 6 will be used for explanation.

The configuration of the waveguide sections 20A and 20B shown in FIG. 6 is almost the same as the configuration of the DFB laser section 10 shown in FIG. 5, but differs in that instead of the active layer C8 of the DFB laser section 10, a waveguide layer C8GU is provided that is connected to the active layer C8 and guides the laser light emitted from the DFB laser section 10 to the modulator section 30, that there is no diffraction grating C7, and that there are no electrodes C1 and C10. Also, because the waveguide sections 20A and 20B do not have electrodes, no openings are formed in the insulating layer C2.

Next, the configuration of the modulator section 30 of the semiconductor laser device C will be described.
FIG. 7 is a cross-sectional view taken along line FF' of the modulator section 30 of the semiconductor laser device C shown in FIG.
The configuration of the modulator section 30 is almost the same as that of the DFB laser section 10, but differs in that, instead of the active layer C8 of the DFB laser section 10, a light absorption layer C8EA is provided which is connected to the waveguide layer C8GU of the waveguide section 20A (20B) and absorbs the laser light emitted from the DFB laser section 10, and in that the diffraction grating C7 is not provided. Thus, the mesa stripe section CmeEA as the second mesa stripe section in the modulator section 30 is configured to include the light absorption layer C8EA.
Further, instead of the electrodes C1, C10 of the DFB laser portion 10, an electrode C10EA serving as a third electrode layer and an electrode C1EA serving as a fourth electrode layer are provided which are formed electrically independent of the electrodes C1, C10 of the DFB laser portion 10.

In addition, an opening CopEA is formed in the insulating layer C2 of the modulator section 30 as a second opening that opens above the light absorbing layer C8EA. As a result, the electrode C1EA is joined to the p-type contact layer C3 only above the light absorbing layer C8EA, and is insulated from the p-type contact layer C3 by the insulating layer C2 in other parts.

As described above, the substrate C9, p-type cladding layers C4-1 and C4-2, p-type contact layer C3, insulating layer C2, buried layer Cbo, and groove portion M in the DFB laser portion 10 are extended from the DFB laser portion 10 and are also formed in the waveguide portions 20A and 20B and the modulator portion 30, respectively.

The configuration of the semiconductor laser device 100 including the semiconductor laser element C configured as above will be described with reference back to FIGS.
As described above, the semiconductor laser device 100 is formed by mounting the semiconductor laser element C on the submount 1. Specifically, the semiconductor laser element C is die-bonded onto the submount 1 by an adhesive such as solder, and an electrode C10 on the downward direction Y2 side is connected to an electrode (not shown) on the submount 1.

Two submount wirings 2 and 2EA, which are electrically independent from each other, are formed on the submount 1. An electrode C1 on the upward Y1 side of the DFB laser portion 10 of the semiconductor laser element C is connected to the submount wiring 2 by a wire 3, and an electrode C1EA of the modulator portion 30 is connected to the submount wiring 2EA by the wire 3.
Thus, a current is supplied to the electrode C1 of the DFB laser portion 10 of the semiconductor laser device C from the submount wiring 2 via the wire 3, and a voltage is applied to the electrode C1EA of the modulator portion 30 from the submount wiring 2EA via the wire 3.

When a current is supplied to the electrode C1 of the DFB laser section 10 of the semiconductor laser element C, the current flows through the layer of the electrode C1 from the connection point P1 between the electrode C1 and the wire 3 shown in FIG. 2 to the connection point P2 between the electrode C1 and the p-type contact layer C3. Then, a current is supplied from this connection point P2 to the active layer C8, causing light emission, and the light of a specific wavelength is intensified by the diffraction grating C7 to emit laser light of a single wavelength. The emitted laser light is guided to the light absorption layer C8EA of the modulator section 30 via the waveguide layer C8GU of the waveguide section 20A.

When a voltage is applied to the electrode C1EA of the modulator section 30 of the semiconductor laser element C, the amount of light absorption in the light absorption layer C8EA of the modulator section 30 changes in response to the application of this voltage. Thus, the laser light emitted by the DFB laser section 10 is modulated in the modulator section 30 and emitted from the laser light emission port Cout via the waveguide layer C8GU of the waveguide section 20B.

Here, in order to improve the heat dissipation in the semiconductor laser element C, a plurality of stud bumps 11 (10 in this embodiment) are provided as protrusions on the electrode C1 of the DFB laser section 10. The stud bumps 11 are balls formed by melting a metallic wire material, for example.

In this embodiment, the tip of the wire material of the wire 3 connecting the electrode C1 and the submount wiring 2 is melted by a wire bonding device to form a ball, which is then bonded onto the electrode C1 to form the stud bump 11. As the wire bonding device, for example, an ultrasonic generator that uses ultrasonic vibrations to melt the metal wire and bond it onto the electrode C1, or a heater that uses heat to melt the wire and thermocompress it onto the electrode C1 can be used.

The positions where these stud bumps 11 are formed on the electrode C1 of the DFB laser section 10 are positions on both outsides of the groove M, that is, positions opposite the side where the active layer C8 is located across the groove M. Furthermore, they are positions spaced apart from the wires 3 so as not to come into contact with the wires 3 that contribute to the electric circuit.
Furthermore, the stud bumps 11 are formed after the semiconductor laser element C is die-bonded onto the submount 1 and before the wires 3 are wired. If an attempt is made to form the stud bumps 11 after wiring the wires 3 that contribute to the electric circuit, there is a possibility that a part of the wire bonding device will come into contact with the wires 3 during the formation of the stud bumps 11, causing a malfunction. For this reason, the stud bumps 11 are formed before the wires 3 are wired.

The submount 1 and submount wiring 2, 2EA are assumed to be, for example, an aluminum nitride (AlN) substrate or an alumina (Al2O3) substrate on which thin film resistors, joining patterns made of lead-free solder such as Sn/Ag, Sn/Ag/Cu, Sn/Ag/Bi/In, Sn/Ag/Cu/Ni/Ge, Sn/Bi, Sn/Bi/Ag, Sn/Bi/Cu, wiring patterns made of materials such as Au, Cu, Pt, etc. are provided.

The wire material forming the wire 3 and the stud bump 11 is assumed to be, for example, Au, Au alloy, Cu, Al, Ag, etc. As described above, the same wire material is used for the wire connecting the semiconductor laser element C and the submount 1 and the wire material used to form the stud bump 11, with the aim of standardizing the manufacturing process and reducing the number of steps. However, this is not limited to this, and different wire materials may be used in consideration of material costs and compatibility with the material of the semiconductor laser element C.

The effect of improving the heat dissipation of the semiconductor laser element C by the stud bumps 11 and the effect of reducing the stress on the active layer C8 by the semiconductor laser element C having the above configuration will be described below.
As described above, the active layer C8, which is a heat source, is formed in the semiconductor laser element C at a position closer to the electrode C1 on the upward direction Y1 side than to the electrode C10 on the downward direction Y2 side of the semiconductor laser element C. As a result, heat generated in the active layer C8 is more likely to be transferred to the electrode C1 side closer to the active layer C8.

Here, stud bumps 11 are formed on electrode C1, which increases the heat capacity and surface area of electrode C1. Therefore, heat generated in active layer C8 of the semiconductor laser element is conducted more efficiently not only to electrode C10 but also to electrode C1 due to the increased heat capacity of stud bumps 11, and the heat is radiated efficiently due to the increased surface area of electrode C1 due to stud bumps 11. This promotes heat dissipation from electrode C1 from the upward Y1 side of semiconductor laser element C, resulting in improved heat dissipation of semiconductor laser element C.

Furthermore, the active layer C8 is included in the mesa stripe portion Cme, which has a mesa shape, and the upper surface and both side surfaces of this active layer C8 are not configured to abut against an insulating film or the like with low thermal conductivity, but are configured to abut against the p-type cladding layer C4-1, which is a semiconductor layer with high thermal conductivity, and the buried layer Cbo. This allows the heat generated in the active layer C8 to be efficiently transferred to the electrode C1 side, improving the heat dissipation effect.

The substrate C9 formed on the downward direction Y2 side of the active layer C8 is formed so as to ensure a length L1 in the thickness direction Y of 80 μm or more. This length L1 of 80 μm or more is a thickness at which the stress applied to the active layer C8 from the electrode C1 side, such as thermal stress caused by the difference between the thermal expansion coefficient of an adhesive material such as solder and the thermal expansion coefficient of the material of the semiconductor laser element C when bonding the semiconductor laser element C to the submount 1, is reduced to a first value or less, which is a stress within the allowable range in the active layer C8.

As described above, by forming the active layer C8, which is the heat source, in the semiconductor laser element C at a position close to the electrode C1 whose heat capacity and surface area are increased by the stud bump 11 while ensuring the length L1 of the substrate C9 that can reduce the stress applied to the active layer C8 from the electrode C10 side, it is possible to simultaneously achieve the effect of reducing the stress applied to the active layer C8 and the effect of improving the dissipation of heat generated from the active layer C8.

Furthermore, by setting the upper limit of the length L1 of the substrate C9 in the thickness direction Y to 130 μm or less and forming the length L1 of the substrate C9 within the range of 80 μm or more and 130 μm or less, it is possible to suppress cracks, chips, burrs, etc. of the substrate C9 during manufacturing, and to improve the yield. More preferably, the length L1 of the substrate C9 is set to 110 μm or more and 130 μm or less.
In this way, the stress applied to the active layer C8 can be reduced, while the yield during manufacturing can be improved, thereby improving productivity.

2, the opening Cop in the insulating layer C2 is configured to narrow the inlet for supplying current to the active layer C8 to only the connection point P2 above the active layer C8. On the other hand, the width of the active layer C8 in the lateral direction X is shortened on the downward direction Y2 side of the connection point P2 so that the active layer C8 is included in the mesa stripe portion Cme of width W1.
In this way, the active layer C8 does not have the same width in the lateral direction X as the electrode C1 located on the upper side thereof in the Y1 direction. Therefore, the distance in the lateral direction X between the stud bump 11 formed on the electrode C1 and the active layer C8 can be ensured to be equal to or greater than the set second distance H2. This makes it possible to protect the active layer C8 from damage caused by ultrasonic vibrations, heat, and the like applied to the semiconductor laser element C when the stud bump 11 is bonded to the electrode C1.

Furthermore, the stud bump 11 is formed at a position opposite to the side where the active layer C8 is located, across the groove M. In this way, by interposing a groove between the active layer C8 and the stud bump 11 and ensuring a long creepage distance between the active layer C8 and the stud bump 11, the active layer C8 can be protected from damage caused by ultrasonic vibration, heat, and the like when the stud bump 11 is bonded.
Furthermore, if the connection point P1 between the wire 3 that contributes to the electrical circuit and the electrode C1 is formed on the side opposite the groove portion M from the side on which the active layer C8 is located, the active layer C8 can be similarly protected from damage caused by ultrasonic vibration, heat, etc., when the wire 3 is joined.

Furthermore, in this configuration, the active layer C8 is included in the mesa stripe portion Cme, and the path through which the current flows is narrowed to a narrow range of width W1, thereby preventing unintended changes in output characteristics such as kinks in the laser characteristics of the semiconductor laser device. Also, by burying both side surfaces of the active layer C8 with the burying layer Cbo in this manner, leakage current leaking from the active layer C8 to both lateral directions X of the semiconductor laser element C can be suppressed. In addition, because the groove portion M is provided so as to sandwich the active layer C8, this configuration can also further suppress leakage current leaking from the active layer C8 in both lateral directions X.

As described above, the mesa stripe portion Cme, buried layer Cbo, and groove portion M including the active layer C8 in this embodiment achieve both the effect of improving the output characteristics of the semiconductor laser device and the effect of reducing damage to the active layer C8 when the stud bump 11 and the wire 3 are bonded.
The effect of suppressing leakage current by providing the buried layer Cbo and the groove M as described above can be obtained in the waveguide sections 20A and 20B and the modulator section 30 in the same manner.

Here, the stud bump 11 is provided only in the DFB laser section 10 of the semiconductor laser element C, and not in the modulator section 30. This is because in an electroabsorption modulator integrated semiconductor laser (EML-LD) formed by integrating the DFB laser section 10 and the modulator section 30, the electrode area in the DFB laser section does not affect the frequency characteristics of the laser light. Therefore, the stud bump 11 that increases the electrode area is provided only in the DFB laser section 10. On the other hand, if the electrode area in the modulator section 30 is increased by the stud bump, the electrostatic capacitance increases in proportion to the surface area, and the frequency characteristics deteriorate. In this way, by configuring the stud bump 11 not to be provided in the modulator section 30, the element capacitance such as the parasitic capacitance in the modulator section 30 can be reduced, making it possible to accommodate higher speeds and larger capacities in optical communications using the semiconductor laser device 100.

Other configuration examples of the semiconductor laser element C will be described below with reference to FIGS.
FIG. 8 is a cross-sectional view showing the configuration of a semiconductor laser element Cex1 having a different configuration from the semiconductor laser element C shown in FIG.
As shown in FIG. 8, the active layer C8 may be configured not to be included in the mesa stripe portion of the mesa type shape, but to be located on the lower side of the mesa stripe portion in the Y2 direction and to have the same width in the lateral direction X as the electrode C1.

In this case as well, high heat dissipation is achieved since the active layer C8, which is a heat source, is formed in the semiconductor laser element C at a position closer to the electrode C1 on the upward Y1 side than to the electrode C10 on the downward Y2 side of the semiconductor laser element C. Also, in this configuration, by appropriately adjusting the length in the thickness direction Y of the p-type cladding layer C4-2, the active layer C8 can be protected from damage during bonding of the stud bump 11 formed on the electrode C1 on the upward Y1 side of the active layer C8.
In addition, the opening Cop in the insulating layer C2 is configured to limit the inlet for supplying current to the active layer C8 to only the connection point P2 above the active layer C8, and the provision of the groove M makes it possible to suppress leakage current leaking outside the groove M.

FIG. 9 is a cross-sectional view showing the configuration of a semiconductor laser device C1ex2 having a different configuration from the semiconductor laser device C shown in FIG.
9, both side surfaces of the mesa stripe portion Cme including the active layer C8 are in contact with the insulating layer C2. In this manner, both side surfaces of the active layer C8 may be configured not to be buried with the buried layer Cbo.
Even in this case, the active layer C8, which is a heat source, is formed within the semiconductor laser element C at a position closer to the electrode C1 on the upward Y1 side than to the electrode C10 on the downward Y2 side of the semiconductor laser element C, thereby achieving high heat dissipation properties.
In addition, since both sides of the mesa stripe portion Cme are in contact with the insulating layer C2 and the groove portion M is provided, leakage current leaking from the active layer C8 in both lateral directions X of the semiconductor laser element C can be suppressed.

In addition to the above-mentioned semiconductor laser elements Cex1 and Cex2, similar structures are also envisioned, such as a structure in which the diffraction grating C7 is formed on the downward Y2 side of the active layer C8, and a structure in which the groove portion M does not exist.

In this embodiment, the stud bump 11 has been described as an example of a protrusion for increasing the heat capacity and surface area of the electrode C1, but this is not limited to this. Any configuration of protrusion may be used as long as it can increase the heat capacity and surface area of the electrode C1. For example, it is envisioned that bumps formed by plating, pillar bumps, solder bumps, and solder balls may be used as the protrusion.

In addition, there is no particular limit to the number or number of rows of stud bumps 11 on electrode C1, and these may be adjusted to match the device length in the vertical direction Z and the device width in the horizontal direction X of the semiconductor laser element C. Naturally, when forming stud bumps 11 on electrode C1, the more ultrasonic wire bonding is performed, the more likely it is that the semiconductor laser element C will be damaged by the ultrasonic waves, resulting in defects. For this reason, it is advisable to form only the minimum number of stud bumps necessary to ensure the desired heat dissipation performance.

In the above explanation, the first conductivity type is n-type and the second conductivity type is p-type, but the first conductivity type may be p-type and the second conductivity type may be n-type. That is, the semiconductor substrate formed on the submount side of the active layer may be a p-type semiconductor substrate, and the semiconductor layer formed above the active layer may be an n-type semiconductor substrate.

If a problem occurs during the formation of the stud bumps 11 and the stud bumps 11 are not completely bonded to the electrode C1, the stud bumps 11 may peel off due to a reduction in the bonding area between the semiconductor laser element C and the electrode C1. In this case, if the stud bumps 11 are close to each other, and the peeled stud bumps 11 come into contact with each other, this contact may form an unexpected circuit (current path). Therefore, it is preferable to form the stud bumps 11 so that they are separated from each other by a set distance and do not come into contact with each other. In addition, by making each stud bump 11 independent, the surface area of the stud bumps 11 can be maximized, and a gap can be secured between the independent stud bumps 11 so that, for example, a cooling fluid can pass through smoothly. This enables efficient heat exchange and heat dissipation.

In the semiconductor laser device according to the present embodiment configured as described above,
A semiconductor laser device comprising a laser section that emits laser light and a modulator section that modulates the laser light emitted from the laser section, the laser section and the modulator section being integrated on a submount,
The laser portion includes a first electrode layer that is in contact with a surface of the submount on a first direction side in a thickness direction and is connected to the submount;
a first conductive type semiconductor layer provided on the first direction side of the first electrode layer;
an active layer provided on the first direction side of the first conductive type semiconductor layer;
a second conductive type semiconductor layer provided on the first direction side of the active layer;
a second electrode layer provided on the first direction side of the second conductive type semiconductor layer,
a length in the thickness direction of the first conductive type semiconductor layer is formed to a length L1 at which a stress in the active layer applied from the first electrode layer side is equal to or less than a first value, and a length in the thickness direction of the second conductive type semiconductor layer is formed to a length L2 that is shorter than the length L1 of the first conductive type semiconductor layer;
a protruding portion protruding from the second electrode layer toward the first direction on the second electrode layer, the protruding portion being spaced apart from a first connection line that supplies a current to the active layer via the second electrode layer;
It is something.

In this way, the length L2 in the thickness direction Y of the second conductive type semiconductor layer (p-type cladding layers C4-1, C4-2, p-type contact layer C3) provided on the first direction (upward) side of the active layer is formed to be shorter than the length L1 of the first conductive type semiconductor layer (substrate C9). In other words, the active layer, which serves as a heat source, is located in a position within the semiconductor laser element closer to the second electrode layer (electrode C1) on the first direction (upward) side than to the first electrode layer (electrode C10) on the second direction (downward) side of the semiconductor laser element. As a result, heat generated in the active layer is transferred more to the electrode C1 on the upward side closer to the active layer.

A protrusion (stud bump) that protrudes in the first direction (upward) is provided on the second electrode layer (electrode C1) close to the active layer to increase the heat capacity and surface area of the second electrode layer (electrode C1). Heat is transferred more efficiently to the electrode C1 side due to the increased heat capacity of the stud bump, and heat is radiated efficiently due to the surface area of electrode C1, which is also increased by the stud bump. In this way, heat dissipation from the electrode C1 of the semiconductor element is promoted, ensuring high heat dissipation performance.

Furthermore, because the first electrode layer (electrode C10) far from the active layer is connected to the submount, the submount is not soldered to the second electrode layer (electrode C1) close to the active layer. As a result, stress caused by soldering the submount is not applied to the active layer from the electrode C1 side close to the active layer.

In addition, the thickness direction length L1 of the first conductivity type semiconductor layer (substrate C9) on the second direction (downward) side of the active layer is formed so as to ensure a length that ensures that the stress in the active layer applied from the first electrode layer (electrode C10) side joined to this submount is equal to or less than a set first value.
In this manner, by configuring the stress in the active layer to be equal to or less than the first value of the allowable range, it is possible to prevent distortion in the active layer and thus wavelength skipping of the laser light, etc., thereby obtaining a high-performance semiconductor laser device.

Furthermore, the protrusion (stud bump) is provided away from the first connection line (wire) that supplies current to the active layer. This prevents the current supplied to the active layer via the wire from flowing through an unintended path via the stud bump, ensuring the performance of the semiconductor laser device.

As described above, the semiconductor laser device of this embodiment achieves both high performance by reducing the stress applied to the active layer and improved heat dissipation.

In the semiconductor laser device according to the present embodiment configured as described above,
two grooves recessed from a surface of the second electrode layer on the first direction side toward a second direction opposite to the first direction are formed at a first distance from each other and extend in a third direction perpendicular to the thickness direction;
an insulating layer is formed between the second electrode layer and the second conductive type semiconductor layer, the insulating layer having a first opening portion formed between the groove portions and extending in the third direction;
The protrusion is formed at a position outside the groove, which is a position on the opposite side of the groove from a side on which the first opening is located.
It is something.

In this manner, two grooves extending in the third direction (vertical direction) are formed on the second electrode layer (electrode C1). A first opening is then formed in the insulating layer between the two grooves. In this manner, the inlet for supplying current to the active layer is narrowed down to the region between the two grooves. A protrusion (stud bump) is then formed on the outside of the groove, on the side opposite the first opening across the groove.
This allows the location of light emission in the active layer to be separated from the stud bump. By providing an additional groove between the stud bump and the location of light emission in the active layer, the creepage distance between them can be further increased. This protects the location of light emission in the active layer from damage caused by ultrasonic vibration, heat, etc., during bonding of the stud bump.

In the semiconductor laser device according to the present embodiment configured as described above,
a first mesa stripe portion having a mesa shape in a cross section in the thickness direction, including the first conductive type semiconductor layer and the active layer, and extending in the third direction;
the first mesa stripe portion is formed between the groove portions,
the protrusion is formed at a position outside the groove at a distance equal to or greater than a second distance from the active layer;
It is something.

In this way, the active layer is configured to be included in the first mesa stripe portion formed between the two grooves. The protrusions (stud bumps) are formed at positions outside the grooves so as to be at least a set second distance away from the active layer. In this way, by ensuring the second distance between the active layer and the stud bumps and further by interposing a groove between them, the active layer can be reliably protected from damage caused by ultrasonic vibrations, heat, etc., during bonding of the stud bumps.

In the semiconductor laser device according to the present embodiment configured as described above,
a buried layer, which is a semiconductor layer, is formed on each of both side surfaces of the first mesa stripe portion;
It is something.

In this way, the semiconductor layers are formed on both side surfaces of the first mesa stripe. That is, both side surfaces of the active layer included in the first mesa stripe are filled with the semiconductor layers having high thermal conductivity. This allows the heat generated in the active layer to be efficiently transferred to the stud bumps via the semiconductor layers, improving the heat dissipation effect.
Furthermore, even in cases where a groove is provided between the active layer and the stud bump in order to protect the active layer from damage during bonding of the stud bump, by embedding the active layer in a semiconductor layer with high thermal conductivity in this manner, the heat generated in the active layer can be efficiently transferred to the stud bump, regardless of the presence or absence of a groove.

In the semiconductor laser device according to the present embodiment configured as described above,
The protrusion is made of the same material as the material constituting the first connection line.
It is something.
Further, a method for manufacturing the semiconductor laser device according to the present embodiment configured as described above includes the steps of:
A wire material is melted by a wire bonding device to wire the first connection line;
The wire material is melted by the wire bonding device to form the protrusion.
It is something.

In this way, the protrusion (stud bump) is made of the same material as the material that makes up the first connection line (wire). That is, the wire material used for the first connection line (wire) that contributes to the electric circuit to supply current to the active layer is also used to form the protrusion (stud bump). In this way, instead of using a separate component such as a heat sink as the protrusion, a stud bump made from melted wire is used, eliminating the expense of additional components such as a heat sink.

In the mass production of semiconductor devices, where prices are falling rapidly and continuous cost reductions are required, it is clear that the additional component cost for one heat sink per element is a major obstacle. Therefore, by using the wire material, which is essential in the manufacture of semiconductor laser devices, in the formation of stud bumps as well, it is possible to achieve significant cost reductions.

In this way, additional parts such as a heat sink as a protruding part are not required, and the formation of the semiconductor laser device can be completed with the parts that constitute the semiconductor laser device without relying on components other than the semiconductor laser device. Therefore, it is also effective in the sales business of chip finished products that only sell semiconductor laser devices.
Furthermore, since components such as a heat sink are not joined to the second electrode layer (electrode C1) on the first direction (upward) Y1 side of the semiconductor element, it is possible to prevent malfunctions caused by an inability to obtain height alignment accuracy between the heat sink and the second electrode layer (electrode C1) of the semiconductor laser element, or poor contact between the heat sink and the second electrode layer (electrode C1) of the semiconductor laser element.

In the semiconductor laser device according to the present embodiment configured as described above,
The length L1 of the first conductive type semiconductor layer is formed to be 80 μm or more and 130 μm or less.
It is something.

In this way, by making the length in the thickness direction of the first conductive type semiconductor layer (substrate C9) provided on the submount side from the active layer 80 μm or more and 130 μm or less, it is possible to reduce the stress applied to the active layer while suppressing cracks, chips, burrs, etc. of the semiconductor element during manufacturing. This improves the yield of the semiconductor elements and increases productivity.

In the semiconductor laser device according to the present embodiment configured as described above,
the modulator section is disposed alongside the laser section on the same submount;
the first conductive type semiconductor layer and the second conductive type semiconductor layer in the laser section are formed in the modulator section by extending from the laser section;
The modulator section includes:
a third electrode layer that is in contact with a surface of the submount on the first direction side and is connected to the submount, and is formed on a second direction side of the first conductivity type semiconductor layer that is opposite to the first direction;
a fourth electrode layer provided on the first direction side of the second conductive type semiconductor layer;
a light absorbing layer provided between the first conductive type semiconductor layer and the second conductive type semiconductor layer, connected to the active layer in the laser portion, and absorbing light emitted from the laser portion in response to a voltage applied between the third electrode layer and the fourth electrode layer;
It is something.

In this manner, the first conductive type semiconductor layer (substrate C9) and the second conductive type semiconductor layer (p-type cladding layers C4-1, C4-2, p-type contact layer C3) in the laser section (DFB laser section) are extended from the laser section (DFB laser section) and are also formed in the modulator section.
In this way, heat generated by photocurrents in the light absorption layer of the modulator section can be transferred to the p-type cladding layers C4-1 and C4-2 and the p-type contact layer C3 on the upper side of the light absorption layer, and dissipated from the stud bump of the DFB laser section. In addition, the stress applied to the light absorption layer from the third electrode (electrode C10EA) side bonded to the submount can be reduced, and further, the yield during manufacturing can be improved.

In the semiconductor laser device according to the present embodiment configured as described above,
the groove portion and the insulating layer in the laser portion are formed in the modulator portion by extending from the laser portion;
the groove portions in the modulator section are recessed from a surface of the fourth electrode layer on the first direction side toward the second direction side and are formed to extend in the third direction at the first distance from each other,
the insulating layer is formed between the fourth electrode layer and the second conductive type semiconductor layer, and the insulating layer has a second opening portion formed between the groove portions and extending in the third direction;
It is something.
In the semiconductor laser device according to the present embodiment configured as described above,
The modulator section includes:
a second mesa stripe portion having a mesa shape in a cross section in the thickness direction, including the first conductive type semiconductor layer and the light absorbing layer, and extending in the third direction;
the second mesa stripe portion is formed between the groove portions;
It is something.

In this way, by providing the grooves, the openings in the insulating layer formed between the grooves, and the mesa stripe section in the modulator section, it is possible to obtain the current confinement effect of suppressing leakage current, the effect of improving heat dissipation, and the effect of improving productivity, similar to those of the DFB laser section.

In addition, when a groove is formed in the DFB laser section, the semiconductor laser element is not limited to a structure in which a groove is similarly formed in the modulator section. For example, the semiconductor element may be configured to have a groove formed in the DFB laser section, but not in the modulator section. Alternatively, the semiconductor element may be configured to have no buried layer formed in the DFB laser section, but not in the modulator section.
The combination of the groove, the mesa stripe portion, and the active layer buried in the buried layer or insulating film can be arbitrarily combined in the DFB laser portion and the modulator portion.

Embodiment 2.
Hereinafter, the second embodiment of the present invention will be described with reference to the drawings, focusing on the differences from the first embodiment. The same parts as those in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.
FIG. 10 is a top view showing a schematic configuration of a semiconductor laser device 200 according to the second embodiment.
FIG. 11 is a cross-sectional view of the semiconductor laser device 200 shown in FIG. 1 taken along line AA'.
FIG. 12 is a side view of the semiconductor laser device 200 shown in FIG.

In the second embodiment, instead of the stud bump 11 of the first embodiment, a wire bridge 211 made of a second connection line is provided on the electrode C1 on the active layer side of the semiconductor laser element C as a protrusion that contributes only to heat dissipation. This wire bridge 211 is configured by connecting the first end and the second end of the second connection line to the electrode C1 with a set third distance H3-1, H3-2 or more between them. As shown in FIG. 12, the intermediate portion between the first end and the second end of the second connection line forming the wire bridge 211 has a gap G between it and the surface of the electrode C1 on the upward Y1 side. In this way, the wire bridge 211 is formed in a bridge shape that protrudes toward the electrode C1 on the upward Y1 side.

The wire bridge 211 is wired within the electrode C1 of the DFB laser section 10 after the semiconductor laser element C is die-bonded to the submount 1 and the wire 3 is wired. At this time, the wire bridge 211 that contributes only to heat dissipation is wired so as not to interfere with and not to come into contact with the wiring of the wire 3 that contributes to the electrical circuit. In addition, the position of the wire 3 within the electrode C1 is arbitrarily and preferentially determined, and the wiring of the wire bridge 211 that contributes only to heat dissipation is changed and adjusted depending on the position of the wire 3 that contributes to the electrical circuit.

Other examples of wiring of the wire bridge 211 in the DFB laser unit 10 will be described below with reference to FIGS.
FIG. 13 is a schematic top view of an electrode C1ex1, showing an example of wiring of the wire bridge 211 in the DFB laser unit 10 of this embodiment.
FIG. 14 is a schematic top view of an electrode C1ex2, showing an example of wiring of the wire bridge 211 in the DFB laser unit 10 of this embodiment.
FIG. 15 is a schematic top view of an electrode C1ex3, showing an example of wiring of the wire bridge 211 in the DFB laser unit 10 of this embodiment.
FIG. 16 is a schematic top view of an electrode C1ex4, showing an example of wiring of the wire bridge 211 in the DFB laser unit 10 of this embodiment.

As described below, the length, number, combination, and wiring position of the wire bridges 211 to be wired vary depending on the size of the semiconductor laser element C.
For example, in the configuration shown in Figure 13, the wire bridge 211 is assumed to be wired in the vertical direction Z parallel to the groove M on both outsides of the groove M in the horizontal direction X so as not to straddle the groove M.

As shown in FIG. 13, when the length ZL from the front end face to the rear end face in the vertical direction Z of the semiconductor laser element C is longer than the width XL in the horizontal direction X of the semiconductor laser element C, arranging the wire bridge 211 in this manner makes it possible to form a longer wire bridge 211 than a configuration in which the wire bridge 211 is formed in the horizontal direction X across the groove portion M. This makes it possible to reduce the number of wire bonding operations required to connect the first and second ends of the wires. Furthermore, with this reduced number of wire bonding operations, it is possible to obtain more heat capacity and ensure high heat dissipation, while also reducing damage to the semiconductor laser element C during wire bonding.

The configuration shown in FIG. 14 also assumes that the width XL of the semiconductor laser element C is longer than the length ZL from the front end face to the rear end face of the semiconductor laser element C. In this case, forming a wire bridge 211 that is wired in the horizontal direction X so as to straddle the groove portion M, as shown in FIG. 14, can provide more heat capacity with less wire bonding and reduce damage to the semiconductor laser element C during wire bonding.

Also, as shown in FIG. 15, even if the length ZL from the front end face to the rear end face in the vertical direction Z of the semiconductor laser element C is longer than the width XL in the horizontal direction X of the semiconductor laser element C, forming a wire bridge 211 diagonally on the electrode C1 is effective in obtaining the most heat capacity in a configuration using one wire bridge 211.

However, when forming the wire bridge 211 diagonally, there is a possibility that a malfunction may occur due to contact with the wire 3 that contributes to the first formed electric circuit, or the height of the wire bridge 211 may become unexpectedly high when wiring above the wire 3. For this reason, when wiring two or more wire bridges 211, or when wiring the wires 3 that contribute to the electric circuit and the wire bridge 211 in close proximity to each other, it is preferable that the wire bridge 211 does not cross other wire bridges 211 or wires 3.

It is also possible to envision a configuration in which the stud bump 11 described in embodiment 1 and other bumps are used in combination, as shown in FIG. 16.

In order to increase the heat capacity of the wire bridge 211, it is effective to maximize the volume of the wire bridge 211. Therefore, it is preferable that the wire material forming the wire bridge 211 is as thick as possible. However, if the wire material is too thick, high energy is required during wire bonding, which may cause problems in the semiconductor laser element C. In general, the dimensions of the semiconductor laser element C are expected to be 100 μm to 200 μm in the horizontal direction X by several hundreds of μm in the vertical direction Z, so in this embodiment, the length of the wire as viewed from above is limited to 1000 μm or less.
Further, the wire diameter of the wire material to be used is also limited to 10 μm to 80 μm, which is assumed for the size of the semiconductor laser element C.
There are also no limitations on the height in the thickness direction Y of the wire bridge 211, which contributes only to heat dissipation, and the wire 3, which contributes to the electrical circuit; however, it is desirable to keep the wiring height as low as possible since this may cause the wire to come loose or cause an unexpected short circuit in the subsequent assembly process.

In the semiconductor laser device according to the present embodiment configured as described above,
a first end and a second end are formed by second connection lines respectively connected onto the second electrode layer, and an intermediate portion between the first end and the second end of the second connection line is wired in a bridge shape so as to have an air gap between the second electrode layer and the second connection line;
It is something.

As a result, the same effects as those of the first embodiment can be obtained, and high heat dissipation properties can be ensured, and a high-performance semiconductor laser device and a method for manufacturing the semiconductor laser device can be obtained.
In this manner, the protrusion (wire bridge) is formed by a second connection line having a first end and a second end connected to the second electrode layer (electrode C1), and the intermediate portion between the first end and the second end of the second connection line is wired so as to have a gap between the second electrode layer (electrode C1), forming a bridge-shaped wire bridge having both a connection start point (first end) and a connection end point (second end) connected to the second electrode layer.
This allows the heat capacity, surface area, number of wire bonding operations, etc. of the protrusion to be adjusted according to the length from the front end face to the rear end face and the lateral width of the semiconductor laser element, thereby ensuring higher heat dissipation in the semiconductor laser device and reducing damage to the semiconductor element.

Embodiment 3.
Hereinafter, the third embodiment of the present invention will be described with reference to the drawings, focusing on the differences from the first embodiment. The same parts as those in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.
FIG. 17 is a top view showing a schematic configuration of a semiconductor laser device 300 according to the third embodiment.
FIG. 18 is a cross-sectional view of the semiconductor laser device 300 shown in FIG. 17 taken along line AA'.
FIG. 19 is a side view of the semiconductor laser device 300 shown in FIG.

In this third embodiment, in the semiconductor laser device 200 shown in the second embodiment, the wire bridge 211 that contributes only to heat dissipation is wired so that its uppermost portion 211max in the thickness direction Y is higher than the uppermost portion 3max of the wire 3 that contributes to the electric circuit. Furthermore, a pillar portion 312 is provided on the submount 1, standing on the upward direction Y1 side.

The height Yh of the column 312 in the thickness direction Y is higher than the top 3max of the wire 3 that contributes to the electric circuit, and lower than the top 211max of the wire bridge 211 that contributes only to heat dissipation. The heat sink 313 as a heat sink is arranged so as to be supported by the end of the column 312 in the upper direction Y1 on the upper Y1 side of the wire bridge 211 that contributes only to heat dissipation. As a result, the heat sink 313 presses the wire bridge 211 downward in the Y2 direction, so that the top 211max of the wire bridge 211 and the heat sink 313 come into contact, but do not come into contact with the top 3max of the wire 3. The heat sink 313 is thus joined and fixed to the submount 1 via the column 312 provided between the heat sink 313 and the submount 1.

Although the figure shows a configuration in which only one pillar portion 312 is arranged, a plurality of pillar portions 312 may be provided depending on the shape, heat capacity, etc. of the heat sink 313 .
In addition, since the wire bridge 211, which contributes only to heat dissipation, is basically cylindrical, it is expected that the contact area with the heat sink is small. To solve this problem, before the wire bridge 211 is brought into contact with the column portion 312, the heat sink 313 is coated with heat sink grease 314 on the surface on the lower Y2 side. It is assumed that the heat sink grease 314 is printed on the heat sink by screen printing. It is assumed that the heat sink 313 is cut after the heat sink grease 314 is printed, but by combining with a technology that can print within a minute area of 1 mm x 1 mm or less, it is also possible to cut the heat sink and then print the heat sink grease 314.

The heat sink 313 and the pillars 312 are assumed to be made of a material with excellent thermal conductivity, such as metal materials in general, such as aluminum (Al) material or argon (Ag) material, or the same material as the submount 1, such as an aluminum nitride (AlN) substrate or alumina (Al2O3), etc.

The semiconductor laser device according to the present embodiment configured as described above has:
the first connection line is wired so as not to exceed a highest portion of the second connection line that has a highest height from the second electrode layer;
a column portion extending in the first direction from a surface of the submount on the first direction side,
the heat sink is disposed on a side of the second connection line in the first direction and is supported by the pillar portion,
The length of the column portion in the thickness direction is set to a length such that the heat sink presses down the highest portion of the second connection line in the second direction so that the second connection line and the heat sink come into contact with each other, but are not in contact with the first connection line.
It is something.

As a result, the same effects as those of the first embodiment can be obtained, and high heat dissipation properties can be ensured, and a high-performance semiconductor laser device and a method for manufacturing the semiconductor laser device can be obtained.
In this manner, the first connection line (wire) that contributes to the electric circuit is wired so as not to exceed the highest part, which is the highest point of the second connection line (wire bridge) that does not contribute to the electric circuit. In addition, the heat sink (heat sink plate) supported by the pillar part erected on the submount is disposed so as to press down the highest part of the second connection line (wire bridge) that does not contribute to the electric circuit, and not to come into contact with the first connection line (wire) that contributes to the electric circuit.

In this way, a heat sink (heat sink plate) with excellent thermal conductivity is provided, which is joined to the submount via the pillar portion. Then, the second connection line (wire bridge) serving as a protrusion that contributes only to heat dissipation is brought into contact with this heat sink (heat sink plate). This improves the heat dissipation properties of the wire bridge, and further improves the heat dissipation properties from the electrode C1 on the upward Y1 side of the active layer. In addition, because the pillar portion is joined to the submount, a heat dissipation effect is also obtained by heat transfer to the submount side via the pillar portion.

Furthermore, rather than directly joining the semiconductor element to a heat sink or the like with solder, the highest part of a bridge-shaped second connection wire (wire bridge) having cushioning properties and wired in a bridge shape so as to have a gap between it and the second electrode layer (electrode C1) is brought into contact with the heat sink (heat sink).
As a result, even in a configuration using a heat sink, the stress caused by the adhesive for bonding the heat sink can be absorbed by the wire bridge and not applied to the active layer of the semiconductor laser element, thereby preventing problems such as wavelength jumps and improving the performance of the semiconductor laser device.

Furthermore, because the wire bridge that comes into contact with the heat sink and contributes only to heat dissipation has a cushioned bridge shape, height control when attaching the heat sink only requires precision equivalent to the diameter of several of the wires that make up the wire bridge. This makes it possible to prevent poor contact between the heat sink and the semiconductor laser element, as well as to prevent malfunctions of the semiconductor laser element caused by contact with the heat sink, and further simplifies the manufacturing process.

In addition, the thickness direction length of the column is formed to a length that ensures that the heat sink does not come into contact with the wires that contribute to the electrical circuit, so that the current supplied to the active layer via the wires can be prevented from flowing through an unintended path via the heat sink, ensuring the performance of the semiconductor laser device.

Although the present application describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations.
Therefore, countless modifications not illustrated are conceivable within the scope of the technology disclosed in the present application, including, for example, modifying, adding, or omitting at least one component, and further, extracting at least one component and combining it with a component of another embodiment.

1 Submount, 3 Wire (first connection line), 11 Stud bump (protrusion),
10 laser section, 30 modulator section, 100, 200, 300 semiconductor laser device,
211 Wire bridge (protruding portion), 312 Pillar portion, 313 Heat sink (heat sink),
C1 electrode (first electrode layer), C1EA electrode (third electrode layer), C2 insulating layer,
C3 p-type contact layer (second conductive type semiconductor layer),
C4-1 p-type cladding layer (second conductive type semiconductor layer),
C4-2 p-type cladding layer (second conductive type semiconductor layer),
C5 p-type block layer (buried layer), C6 n-type block layer (buried layer),
C8 active layer, C9 substrate (first conductive type semiconductor layer), C10 electrode (second electrode layer),
C10EA electrode (fourth electrode layer), Cme first mesa stripe portion,
CmeEA second mesa stripe portion, Cbo buried layer,
Cop opening (first opening).

Claims (10)

A semiconductor laser device comprising a laser section that emits laser light and a modulator section that modulates the laser light emitted from the laser section, the laser section and the modulator section being integrated on a submount,
The laser portion includes a first electrode layer that is in contact with a surface of the submount on a first direction side in a thickness direction and is connected to the submount;
a first conductive type semiconductor layer provided on the first direction side of the first electrode layer;
an active layer provided on the first direction side of the first conductive type semiconductor layer;
a second conductive type semiconductor layer provided on the first direction side of the active layer;
a second electrode layer provided on the first direction side of the second conductive type semiconductor layer,
The first conductive type semiconductor layer has a length L1 in the thickness direction of 80 μm or more , and the second conductive type semiconductor layer has a length L2 in the thickness direction of the first conductive type semiconductor layer, the length L2 being shorter than the length L1 of the first conductive type semiconductor layer;
a protruding portion protruding from the second electrode layer toward the first direction on the second electrode layer, the protruding portion being spaced apart from a first connection line that supplies a current to the active layer via the second electrode layer;
two grooves recessed from a surface of the second electrode layer on the first direction side toward a second direction opposite to the first direction are formed at a first distance from each other and extend in a third direction perpendicular to the thickness direction;
an insulating layer is formed between the second electrode layer and the second conductive type semiconductor layer, the insulating layer having a first opening portion formed between the groove portions and extending in the third direction;
the protrusion is formed only at a position outside the groove, the position being on the opposite side of the groove from the side on which the first opening is located ,
a first mesa stripe portion having a mesa shape in a cross section in the thickness direction, including the first conductive type semiconductor layer and the active layer, and extending in the third direction;
the first mesa stripe portion is formed between the groove portions,
the active layer is formed only in the first mesa stripe portion,
buried layers , which are semiconductor layers, are formed between both side surfaces of the first mesa stripe portion along the third direction and both side surfaces of the active layer along the third direction , the buried layers being in contact with both side surfaces of the active layer and extending in the third direction ;
the buried layer is formed continuously from both side surfaces of the active layer to a position on the second direction side of the protruding portion outside the groove portion.
Semiconductor laser device. The protrusion is made of the same material as the material constituting the first connection line.
2. The semiconductor laser device according to claim 1 . The length L1 of the first conductive type semiconductor layer is formed to be 80 μm or more and 130 μm or less.
3. The semiconductor laser device according to claim 1 . The protrusion is
a first end and a second end are formed by second connection lines respectively connected onto the second electrode layer, and an intermediate portion between the first end and the second end of the second connection line is wired in a bridge shape so as to have an air gap between the second electrode layer and the second connection line;
4. The semiconductor laser device according to claim 1, wherein the first and second electrodes are arranged parallel to each other. a heat sink disposed in contact with the second connection line and not in contact with the first connection line;
5. The semiconductor laser device according to claim 4 . the first connection line is wired so as not to exceed a highest portion of the second connection line that has a highest height from the second electrode layer;
a column portion extending in the first direction from a surface of the submount on the first direction side,
the heat sink is disposed on a side of the second connection line in the first direction and is supported by the pillar portion,
a length in the thickness direction of the column portion is set to a length such that the heat sink presses down the highest portion of the second connection line in the second direction so that the second connection line and the heat sink come into contact with each other, but are not in contact with the first connection line;
6. The semiconductor laser device according to claim 5 . the modulator section is disposed alongside the laser section on the same submount;
the first conductive type semiconductor layer and the second conductive type semiconductor layer in the laser section are formed in the modulator section by extending from the laser section;
The modulator section includes:
a third electrode layer that is in contact with a surface of the submount on the first direction side and is connected to the submount, and is formed on a second direction side of the first conductive type semiconductor layer that is opposite to the first direction;
a fourth electrode layer provided on the first direction side of the second conductive type semiconductor layer;
a light absorbing layer provided between the first conductive type semiconductor layer and the second conductive type semiconductor layer, connected to the active layer in the laser portion, and absorbing light emitted from the laser portion in response to a voltage applied between the third electrode layer and the fourth electrode layer;
7. The semiconductor laser device according to claim 1, wherein the first and second electrodes are arranged parallel to each other. the groove portion and the insulating layer in the laser portion are formed in the modulator portion by extending from the laser portion;
the groove portions in the modulator section are recessed from a surface of the fourth electrode layer on the first direction side toward the second direction side and are formed to extend in the third direction at the first distance from each other,
the insulating layer is formed between the fourth electrode layer and the second conductive type semiconductor layer, and the insulating layer has a second opening portion formed between the groove portions and extending in the third direction;
8. The semiconductor laser device according to claim 7 . The modulator section includes:
a second mesa stripe portion having a mesa shape in a cross section in the thickness direction, including the first conductive type semiconductor layer and the light absorbing layer, and extending in the third direction;
the second mesa stripe portion is formed between the groove portions;
9. The semiconductor laser device according to claim 8 . 10. A method for manufacturing a semiconductor laser device according to claim 1, comprising the steps of:
A wire material is melted by a wire bonding device to wire the first connection line;
The wire material is melted by the wire bonding device to form the protrusion.
A method for manufacturing a semiconductor laser device.