JP2014175565A - Semiconductor laser device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor laser device which can radiate a laser beam from a semiconductor laser element with high efficiency; or provide a semiconductor laser device in which a semiconductor laser element has high generation efficiency of a laser beam and which can radiate a laser beam from the semiconductor laser element with high efficiency.SOLUTION: In a semiconductor laser device where a semiconductor laser element is bonded to a surface of a tabular sub-mount via a first solder layer and the sub-mount to which the semiconductor laser element is bonded is bonded to a surface of a heat sink via a second solder layer, at least a surface and a rear face of the sub-mount are subjected to plating and a solder-rising stop band composed of a band-like non-plating part which is not subjected to plating is formed and extends in a circumferential direction at least over a whole circumference of a circumferential side surface of the sub-mount.

Description

  The present invention relates to a semiconductor laser device in which a semiconductor laser element is mounted on a submount.

  Conventionally, a technique for bonding a semiconductor laser element on a submount via a solder layer is known. However, when the solder layer is formed, the solder that has been melted rises due to the surface tension and wettability, so that the solder side rises up to the electrodes of the semiconductor laser element. There is a problem that the semiconductor laser element itself may be short-circuited and damaged.

In order to solve such a problem, for example, Patent Document 1 discloses that the semiconductor laser element and the semiconductor laser element are formed by providing a chamfered portion on the end surface on the joint surface side with the semiconductor laser element of the submount to form a solder pool. It is disclosed that the semiconductor laser element is prevented from being short-circuited so that no solder rises from the bonding surface.
Further, there is known a semiconductor laser device in which a semiconductor laser element is bonded onto a submount, and the submount and a heat sink are further bonded. For example, Patent Document 2 provides an uneven structure on the surface of a heat sink. Thus, it is disclosed that solder rise to the semiconductor laser element is suppressed.

JP 2005-347590 A Japanese Utility Model Publication No. 05-025756

However, as disclosed in Patent Document 1, when the chamfered portion is provided in the submount to form the solder pool, the semiconductor laser element is configured to emit laser light from the side surface. There is a problem that the radiation efficiency of the laser light is lowered by blocking a part of the emitted laser light.
In addition, if the concave and convex portions are provided on the joint surface of the heat sink with the submount, voids are formed on the joint surface, resulting in low adhesion between the submount and the heat sink, and sufficient heat from the semiconductor laser element is obtained. There is also a problem that heat cannot be exhausted, and as a result, the generation efficiency of laser light in the semiconductor laser element is lowered.

The present invention has been made based on the above situation, and an object of the present invention is to provide a semiconductor laser device capable of emitting laser light from a semiconductor laser element with high efficiency.
Another object of the present invention is to provide a semiconductor laser device that has a high generation efficiency of laser light in a semiconductor laser element and can emit laser light from the semiconductor laser element with high efficiency.

In the semiconductor laser device of the present invention, the semiconductor laser element is bonded to the surface of the flat submount via the first solder layer, and the submount to which the semiconductor laser element is bonded is formed on the surface of the heat sink. A semiconductor laser device bonded through two solder layers,
At least the front surface and the back surface of the submount are each plated.
On the peripheral side surface of the submount, a solder rising prevention band made of a non-plated strip-shaped non-plated portion extending in the circumferential direction is formed at least over the entire circumference.

In the semiconductor laser device of the present invention, the submount is made of CuW or Si,
The plating applied to the back surface of the submount is preferably Au plating.

In the semiconductor laser device of the present invention, the semiconductor laser element is bonded to the surface of the flat submount via the first solder layer, and the submount to which the semiconductor laser element is bonded is formed on the surface of the heat sink. A semiconductor laser device bonded through two solder layers,
An excess solder accommodating space is provided at a side end of the heat sink.

In the semiconductor laser device of the present invention, the surplus solder accommodating space is constituted by a chamfered portion in which a surface inclined outward is formed toward the back surface direction of the heat sink at the side end portion of the heat sink.
It is preferable that the length of the excess solder accommodating space in the direction perpendicular to the surface of the submount is larger than the average thickness of the second solder layer.

  In the semiconductor laser device of the present invention, it is preferable that an excess solder accommodating space is provided at a side end portion of the heat sink.

  In the semiconductor laser device of the present invention, a solder rising prevention band made of a strip-shaped non-plated portion that is not plated and extends in the circumferential direction is formed on the entire peripheral surface of the submount. Accordingly, when the peripheral side surface of the submount is plated, the solder that is melted when forming the second solder layer causes solder to rise in the height direction along the plating of the peripheral side surface of the submount. However, this is deterred. Specifically, since the non-plated part has extremely low wettability compared to the plated part, when the solder rise due to the molten solder reaches the non-plated part, Also, it is possible to prevent the solder from rising upward. Accordingly, it is possible to suppress the solder rising due to the solder melted to the semiconductor laser element (die), so that the electrode of the semiconductor laser element contacts the solder and short-circuits, or the laser emitted from the semiconductor laser element. It is possible to prevent a part of the light from being blocked. Therefore, damage to the semiconductor laser element is prevented and high radiation efficiency of the laser light can be obtained.

Further, according to the semiconductor laser device provided with the surplus solder accommodating space of the present invention, when surplus exists in the melted solder when forming the second solder layer, the surplus solder accommodating space accumulates in the surplus solder accommodating space. As a result, it is possible to prevent the solder from rising due to the melted solder. Therefore, it is possible to prevent the electrodes of the semiconductor laser element from being short-circuited by the solder and blocking a part of the laser light emitted from the semiconductor laser element. be able to. Therefore, damage to the semiconductor laser element can be prevented and high radiation efficiency of the laser beam can be obtained.
Furthermore, according to the semiconductor laser device having such a configuration, since the formation of voids in the second solder layer is suppressed, good heat dissipation can be obtained, and as a result, the laser light in the semiconductor laser element can be obtained. High generation efficiency can be obtained.

It is a perspective view which shows the structure in an example of the semiconductor laser apparatus of this invention. It is a side view which shows typically the non-plating part in the semiconductor laser apparatus shown in FIG. It is a side view which shows typically the non-plating part in the conventional semiconductor laser apparatus. It is a schematic diagram which shows the modification of the non-plating part in a semiconductor laser apparatus. It is a schematic cross section which shows the excess solder accommodation space in the semiconductor laser apparatus of this invention. It is a schematic cross section which shows the conventional semiconductor laser apparatus in which the excess solder accommodation space is not formed. It is a schematic cross section which shows the modification of the excess solder accommodation space in a semiconductor laser apparatus.

<First Embodiment>
Hereinafter, embodiments of the semiconductor laser device of the present invention will be described.
FIG. 1 is a perspective view showing a configuration of an example of a semiconductor laser device of the present invention, and FIG. 2 is a side view schematically showing a non-plated portion in the semiconductor laser device shown in FIG.
This semiconductor laser device has a flat semiconductor laser element 10. The semiconductor laser element 10 is mounted on the surface of the flat submount 20 by being bonded via a first solder layer 25. The submount 20 to which the semiconductor laser element 10 is bonded is bonded to the surface of the heat sink 30 made of copper, for example, with the second solder layer 26 interposed therebetween so that the back surface of the submount 20 faces the surface of the heat sink 30. ing.

  The semiconductor laser element 10 functions as a light emitting element. For example, the semiconductor laser element 10 has a long rectangular plate shape, and a side end face 10f along a lengthwise direction is a light emitting surface. Specifically, a plurality of light emitters (not shown) for emitting light are arranged in a straight line in a line along the direction in which the light is emitted, inside the package 11 having a long rectangular plate shape. This is an array type element arranged. In the package 11, a plurality of light extraction portions (not shown) for extracting light emitted from the light emitter to the outside are formed on the side end face 10f along the direction extending in the long direction. These light extraction portions are arranged so as to be aligned in a straight line corresponding to each of the light emitters.

In this semiconductor laser device, the position of the light emission surface of the semiconductor laser element 10 in the light emission direction and the position of the peripheral side surface (front surface 20f) on the light emission surface side of the semiconductor laser element 10 in the submount 20 in the light emission direction. The relationship may be that the light emitting surface of the semiconductor laser element 10 protrudes, for example, 0.01 mm forward in the light emitting direction.
Further, the position of the front surface 20f of the submount 20 and the position of the peripheral side surface (front surface 30f) of the heat sink 30 on the light emitting surface side of the semiconductor laser device 10 are preferably coincident with each other. For example, the front surface 30f of the heat sink 30 may protrude forward by, for example, 0.5 mm within a range where the heat sink 30 does not block the laser light to be emitted. As the front surface 30f of the heat sink 30 protrudes forward, heat generated from the semiconductor laser element 10 can be exhausted.

The semiconductor laser element 10 has an active layer (not shown) made of a material such as an AlGaInP-based semiconductor. For example, the length in the longitudinal direction is 5 to 4 mm, the width is 2 to 1 mm, and the thickness is 0.05 to It has a rectangular plate shape with a length of 0.15 mm.
An electrode (not shown) is provided on each of the front and back surfaces of the semiconductor laser element 10, and an active layer laser oscillates by supplying a current between both electrodes, and light extraction from the side end face 10f is performed. Laser light is emitted from the part.

  The submount 20 is obtained by plating the surface of a base made of a mixed material of Cu (copper) and W (tungsten) or Si (silicon). For example, the length in the longitudinal direction is 12 to 9 mm. , Having a long and rectangular flat plate shape with a width of 2 to 3 mm and a thickness of 0.2 to 0.3 mm.

In the submount 20, plating is applied to at least a surface that is a bonding surface with the semiconductor laser element 10 and a back surface that is a bonding surface with the heat sink 30 of the base constituting the submount 20. The plating part 20a may be formed by plating a part of the plate.
It is preferable that the plating applied to at least the back surface of the submount 20 that is a joint surface with the heat sink 30 is a laminate of Ni (nickel) plating and Au (gold) plating.
The plating thickness is, for example, 0.5 μm.

On the peripheral side surface of the submount 20, a solder rising prevention band is formed that extends in the circumferential direction at least over the entire circumference and includes a non-plated strip-shaped non-plated portion 20 b.
The non-plated portion 20b can be, for example, a single belt-like shape extending from one end to the other end in the horizontal direction at the center portion of the submount 20 in the height direction.

The non-plated portion 20b is formed by the surface on which the base body is exposed without being plated on the peripheral side surface of the submount 20.
The width of the non-plating part 20b should just be 50 micrometers or more.

  The non-plated portion 20b has extremely low wettability compared to the plated portion 20a that has been plated.

  The heat sink 30 can be made of copper or the like. For example, the heat sink 30 is long and has a rectangular thickness of 25 to 26 mm in length, a width of 25 to 26 mm, and a thickness of 6 to 8 mm. It has a flat shape.

  As the solder (first solder material) for forming the first solder layer 25, one containing Sn (tin) is preferably used, and examples thereof include AuSn eutectic solder.

  The thickness of the first solder layer 25 is, for example, 1 to 10 μm.

  As the solder (second solder material) for forming the second solder layer 26, one containing Sn is preferably used, and examples thereof include SnAgCu eutectic solder.

  The thickness of the second solder layer 26 is, for example, 20 to 50 μm.

Such a semiconductor laser device according to the first embodiment can be manufactured, for example, as follows.
That is, first, the submount 20 that is cut into a flat plate and whose surface is plated is formed. Furthermore, a strip-shaped non-plated portion 20b extending in the circumferential direction is formed on the entire surface or a part of the peripheral side surface other than the front and back surfaces of the submount 20. The non-plated portion 20b can be formed by scraping the plating by polishing or laser processing.

Next, the semiconductor laser element 10 is disposed on the surface of the submount 20 having the non-plated portion 20b formed on the peripheral side surface, for example, via a layered first solder material (AuSn eutectic solder) having a thickness of 4 to 6 μm. . Then, after the first solder material is melted by heating to a temperature equal to or higher than its melting point, for example, 320 ° C., the first solder material is cooled and solidified, whereby a thickness of 3 μm is formed on the surface of the submount 20. The semiconductor laser element 10 is bonded via the first solder layer 25.
Then, it arrange | positions in the state which the back surface of the submount 20 contacts on the surface of the heat sink 30 via the layered 2nd solder material (SnAgCu eutectic solder) of thickness 30-50 micrometers. Then, after the second solder material is melted by heating to a temperature equal to or higher than its melting point, the second solder material is cooled and solidified to form a second solder having a thickness of 20 μm on the surface of the heat sink 30. The semiconductor laser device shown in FIG. 1 is manufactured by bonding so that the back surface of the submount 20 contacts through the layer 26.

  The melting of the solder material at the time of bonding of the semiconductor laser element 10 and the submount 20 and at the time of bonding of the submount 20 and the heat sink 30 is performed by inert gas atmosphere such as nitrogen gas atmosphere or nitrogen gas and hydrogen gas in order to prevent oxidation of the solder material. It is preferable to carry out in a mixed gas atmosphere.

  In addition, as a second solder material for forming the second solder layer 26 between the submount 20 and the heat sink 30, the first solder layer 25 between the semiconductor laser element 10 and the submount 20 is used. A material having a melting point lower than that of the first solder material for forming is used. Here, the second solder material heats the heat sink 30 to a temperature slightly lower than the melting point of the second solder material, and is attached to the heat sink 30 in this state. Then, the submount 20 and the heat sink 30 are joined by heating the whole to the melting point of the second solder material that has been attached.

  At this time, when the plated portion 20a exists below the peripheral side surface of the submount 20 due to the melted second solder material, the solder rises along the plated portion 20a, but reaches the non-plated portion 20b. Then, the solder rising is inhibited by the non-plated portion 20b.

  FIG. 3 shows a semiconductor laser device in which a solder rising prevention band made of a non-plated portion is not formed, that is, a semiconductor laser device in which the entire peripheral surface is plated in addition to the front and back surfaces of the submount. As shown, when forming the second solder layer 26, the solder that has been melted along the peripheral side surface of the submount 20 due to the spread of the melted solder due to surface tension and wettability, The molten solder reaches the semiconductor laser element 10. As a result, a part of the laser light emitted from the semiconductor laser element 10 is blocked, or the semiconductor laser element 10 itself is short-circuited and damaged.

  In the semiconductor laser device of the present invention, when electric energy is supplied to the semiconductor laser element 10, the electric energy is converted into light energy, and light is emitted from each light emitter.

  As described above, according to the semiconductor laser device according to the first embodiment described above, when the second solder layer 26 is formed, the molten solder is applied to the plating portion 20a on the peripheral side surface of the submount 20. Even if the solder rises along the height direction, a solder rise prevention band made up of a strip-like non-plated portion 20b that is not plated on the circumferential side surface of the submount 20 is formed over the entire circumference. The non-plated portion 20b has extremely low wettability compared to the plated portion 20a. Therefore, when the solder rising by the melted solder reaches the non-plated portion 20b, the solder rising is prevented from occurring above the non-plated portion 20b. Therefore, it is possible to suppress the solder rising due to the solder melted up to the semiconductor laser element 10, so that the electrode of the semiconductor laser element 10 contacts the solder and is short-circuited, or the laser emitted from the semiconductor laser element 10. It is possible to prevent a part of the light from being blocked. Therefore, damage to the semiconductor laser element 10 can be prevented and high radiation efficiency of the laser beam can be obtained.

Although the semiconductor laser device according to the first embodiment has been described above, the semiconductor laser device can be variously modified.
For example, the non-plated portion 20b is not limited to a single belt-like shape extending over the entire circumference, and may be present at any position in the height direction of the submount 20 over the entire circumference.

Specifically, as shown in FIG. 4A, the non-plated portion 20 b is a single band-shaped member that extends from one end in the horizontal direction to the other end at the lower end in the height direction on the peripheral side surface of the submount 20. It may be.
Further, as shown in FIG. 4B, the non-plated portion 20b may be formed by subjecting the corner edge of the non-plated portion shown in FIG. 4A to R processing.
Moreover, as shown in FIG.4 (c), the non-plating part 20b may be one strip | belt-shaped thing extended diagonally toward the downward direction in the other end from the upper direction in the horizontal direction in each side surface.
Further, as shown in FIG. 4D, the non-plated portion 20b may be formed by scraping off all plating on the peripheral side surface of the submount 20.
In addition, as shown in FIGS. 4E and 4F, the non-plated portion 20b has a plurality of strip-shaped non-plated portions 20b in any one of the height directions of the submount 20 over the entire circumference. Further, it may be arranged in a discontinuous state in which the position in the height direction is shifted.

<Second Embodiment>
The semiconductor laser device according to the second embodiment of the present invention is the first embodiment except that the non-plated portion is not formed and the excess solder accommodating space is provided at the side end portion of the heat sink 30. The configuration is the same as that of
More specifically, as shown in FIG. 5, at the end of the heat sink 30, the back surface direction of the heat sink 30 (FIG. 5) A surface 30A inclined outward (to be referred to as an “inclined surface” hereinafter) 30A is formed, and the surplus solder accommodating space S is formed by a chamfered portion obtained by forming the inclined surface 30A. It has a triangular prism shape.

In the surplus solder accommodating space S, the relationship between the length (A) in the direction horizontal to the surface of the submount 20 and the length (B) in the direction perpendicular to the surface of the submount 20 satisfies B ≧ A. That is, it is preferable that B / A ≧ 1. By having such a configuration, surplus solder when forming the second solder layer 26 easily flows into the surplus solder accommodating space S, and surplus solder can be reliably accumulated in the surplus solder accommodating space.
The aspect ratio (B / A) of the excess solder accommodating space S is set to 1 or more, and preferably 1 to 2. However, the smaller the aspect ratio (B / A), the larger the solder rising amount (height). .

  In the surplus solder accommodating space S, the length (B) in the direction perpendicular to the surface of the submount 20 is larger than the average thickness of the second solder layer 26. By having such a structure, the effect that solder rising can be suppressed reliably is acquired.

  In the surplus solder accommodating space S, the length in the direction horizontal to the surface of the submount 20 (A) is different depending on the thickness of the submount 20, but is 0.05 to 0.08 mm, for example.

Moreover, it is preferable that the volume of the excess solder accommodating space S is, for example, 0.04 to 0.15 mm ³ .

  In the semiconductor laser device in which the excess solder accommodating space S is not formed, as shown in FIG. 6, when the second solder layer is formed, the melted solder is spread by surface tension and wettability. As a result, the solder that has been melted along the peripheral side surface of the submount 20 rises, and the melted solder reaches the semiconductor laser device 10. As a result, a part of the laser light emitted from the semiconductor laser element 10 is blocked, or the semiconductor laser element 10 itself is short-circuited and damaged.

Such a semiconductor laser device according to the second embodiment can be manufactured in the same manner as the semiconductor laser device according to the first embodiment.
Since the surplus solder accommodating space S is formed in this semiconductor laser device, the molten second solder material flows into the surplus solder accommodating space S and accumulates when the submount 20 and the heat sink 30 are joined. As a result, the solder rising due to the solder melted along the peripheral side surface of the submount 20 is suppressed.

As described above, according to the semiconductor laser device according to the above-described second embodiment, when there is surplus in the solder melted when the second solder layer 26 is formed, the surplus solder accommodating space S. Therefore, it is possible to prevent the solder from rising due to the molten solder. For this reason, it is possible to prevent the electrodes of the semiconductor laser element 10 from being short-circuited by solder and to block a part of the laser light emitted from the semiconductor laser element, and therefore, damage to the semiconductor laser element is prevented. At the same time, high radiation efficiency of laser light can be obtained.
Furthermore, according to the semiconductor laser device having such a configuration, since the surface of the heat sink 30 is planar, it is possible to suppress the formation of voids in the second solder layer 26, and thus good heat dissipation is achieved. As a result, high generation efficiency of laser light in the semiconductor laser element 10 is obtained.

Although the semiconductor laser device according to the second embodiment has been described above, the semiconductor laser device can be variously modified.
For example, the shape of the excess solder accommodating space S is not limited to the triangular prism shape having the inclined surface 30A, and may be formed by a quadrangular prism-shaped depression as shown in FIG.

<Third Embodiment>
The semiconductor laser device according to the third embodiment of the present invention is the same as that of the second embodiment except that an inclined surface is formed on the heat sink and an excess solder accommodating space is formed. And a structure in which a solder rising prevention band made of a non-plated portion is formed on the submount.

As described above, according to the semiconductor laser device according to the third embodiment described above, when the second solder layer is formed, if there is a surplus in the melted solder, the surplus solder accommodating space is provided. In addition, even if the solder rises in the height direction along the part where the peripheral side surface of the submount is plated by the melted solder, the peripheral side surface of the submount is plated in the circumferential direction. Solder rising prevention band consisting of non-plated non-plated part is formed, and the non-plated part has extremely low wettability compared with the plated part, so molten solder When the solder rise due to the solder reaches the non-plated portion, it is suppressed that the solder rise occurs above the non-plated portion. Accordingly, it is possible to suppress the solder rising due to the solder melted to the semiconductor laser element, so that the electrode of the semiconductor laser element is brought into contact with the solder and short-circuited, or one of the laser beams emitted from the semiconductor laser element. Therefore, the semiconductor laser device can be prevented from being damaged and high radiation efficiency of the laser beam can be obtained.
Furthermore, according to the semiconductor laser device having such a configuration, since the surface of the heat sink is planar, it is possible to suppress the formation of voids in the second solder layer, and thus good heat dissipation can be obtained. As a result, high generation efficiency of laser light in the semiconductor laser element can be obtained.

DESCRIPTION OF SYMBOLS 10 Semiconductor laser element 10f Side end surface 11 Package 20 Submount 20a Plating part 20b Non-plating part 20f Front surface 25 First solder layer 26 Second solder layer 30 Heat sink 30A Inclined surface 30f Front surface S Excess solder accommodation space

Claims (5)

The semiconductor laser element is bonded to the surface of the flat submount via the first solder layer, and the submount to which the semiconductor laser element is bonded is bonded to the surface of the heat sink via the second solder layer. A semiconductor laser device comprising:
At least the front surface and the back surface of the submount are each plated.
A semiconductor laser device characterized in that a solder rising prevention band made of a non-plated strip-shaped non-plated portion extending in the circumferential direction is formed at least on the peripheral side surface of the submount. The submount is made of CuW or Si,
2. The semiconductor laser device according to claim 1, wherein the plating applied to the back surface of the submount is Au plating. The semiconductor laser element is bonded to the surface of the flat submount via the first solder layer, and the submount to which the semiconductor laser element is bonded is bonded to the surface of the heat sink via the second solder layer. A semiconductor laser device comprising:
A semiconductor laser device, wherein an excess solder accommodating space is provided at a side end of the heat sink. The surplus solder accommodating space is configured by a chamfered portion in which a surface inclined outward is formed toward the back surface direction of the heat sink at the side end portion of the heat sink,
4. The semiconductor laser device according to claim 3, wherein a length of the excess solder accommodating space in a direction perpendicular to the surface of the submount is larger than an average thickness of the second solder layer. 3. The semiconductor laser device according to claim 1, wherein a surplus solder accommodating space is provided at a side end portion of the heat sink.

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