JP2009004561A - Laser light source device and manufacturing method thereof, and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser light source device which surely improves heat radiation properties from a gap between a substrate and a semiconductor laser element to prevent the substrate and semiconductor laser element from being strained, and to provide a manufacturing method therefor and an image display device. <P>SOLUTION: A projection portion 22 to be put in a recessed portion 17 of the substrate 20 is formed at a position corresponding to the recessed portion 17, the projection portion 22 is formed of a material having higher heat conductivity than air, and the gap G is formed between the semiconductor laser element 10 and projection portion 22. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a laser light source device, a manufacturing method thereof, and an image display device.

2. Description of the Related Art Conventionally, there is known a laser light source device that can reduce thermal resistance and improve element reliability by filling a gap between a substrate and a semiconductor chip in a bonding surface with excellent thermal conductivity. (For example, refer to Patent Document 1).
JP-A-6-188328

  However, the conventional laser light source device described above uses an insulating filler in which fine particles having high thermal conductivity are mixed in an insulating binder, melts the insulating filler, and causes a gap between the bonding surface of the substrate and the semiconductor chip by capillary action. Is filled. For this reason, when the gap between the substrate and the semiconductor chip is relatively large, the density of the insulating filler is high, or the wettability of the groove with the insulating filler is low, the gap is insulated by capillarity. There is a problem that it is difficult to fill the conductive filler.

  In addition, when the insulating filler is completely filled in the gap between the substrate and the semiconductor chip due to capillarity, the substrate and the semiconductor chip are stressed due to the difference in thermal expansion coefficient between the insulating filler and the substrate. There is a problem that occurs.

  Therefore, the present invention provides a laser light source device, a manufacturing method thereof, and an image display device that can reliably improve the heat dissipation of the gap between the substrate and the semiconductor laser element and prevent stress from being generated in the substrate and the semiconductor laser element. It is to provide.

  In order to solve the above problems, a laser light source device of the present invention includes a semiconductor laser element and a substrate on which the semiconductor laser element is mounted, and a recess is formed on a surface of the semiconductor laser element on the substrate side. In the laser light source device, a convex portion accommodated in the concave portion is formed at a position corresponding to the concave portion of the substrate, and the convex portion is formed of a material having higher thermal conductivity than air, and the semiconductor laser A gap is formed between the element and the convex portion.

With this configuration, the radiant heat of the semiconductor laser element can be absorbed by the convex portion accommodated in the concave portion, and the heat generated in the semiconductor laser element can be diffused to the substrate.
Further, when the temperature of the semiconductor laser element rises as the semiconductor laser element emits light, the distance between the concave portion and the convex portion varies due to the difference in thermal expansion coefficient between the substrate and the semiconductor laser element. At this time, variation in the distance between the concave portion and the convex portion can be allowed by the gap between the concave portion and the convex portion.
Therefore, the heat dissipation of the semiconductor laser element can be reliably improved by the convex portion accommodated in the concave portion. In addition, it is possible to prevent stress from being generated in the substrate and the semiconductor laser element due to the gap between the concave portion and the convex portion.

In the laser light source device of the present invention, the concave portion is formed around the light emitting portion of the semiconductor laser element.
By comprising in this way, a convex part can be arrange | positioned around the light emission part which generate | occur | produces the heat most, and the heat dissipation of a semiconductor laser element can be improved more.

The laser light source device of the present invention is characterized in that a plurality of the light emitting portions are formed in the semiconductor laser element.
With this configuration, the output of the semiconductor laser element can be increased.

In the laser light source device of the present invention, an electrode is formed in the concave portion along at least a part of an inner surface of the concave portion, and an insulating layer is formed on the surface of the convex portion. To do.
By comprising in this way, an electrode and a convex part can be electrically insulated and a short circuit of an electrode and a convex part can be prevented.

According to another aspect of the present invention, there is provided a method for manufacturing a laser light source device, comprising: a semiconductor laser element; and a substrate on which the semiconductor laser element is mounted, wherein the semiconductor laser element has a concave portion formed on a surface of the substrate side. In the manufacturing method, on the surface of the substrate, a step of forming a heat dissipation material layer with a material having a higher thermal conductivity than air, and patterning the heat dissipation material layer to form a protrusion at a position corresponding to the recess And a step of accommodating the convex portion in the concave portion and mounting the semiconductor laser element on the substrate.
By manufacturing in this way, a convex part with high heat dissipation can be reliably accommodated inside the concave part. Further, in the step of forming the convex portion, a gap can be formed between the convex portion and the concave portion by forming the shape of the convex portion smaller than the shape of the inner surface of the concave portion.

According to another aspect of the present invention, there is provided a method for manufacturing a laser light source device, comprising: a semiconductor laser element; and a substrate on which the semiconductor laser element is mounted, wherein the semiconductor laser element has a concave portion formed on a surface of the substrate side. A manufacturing method comprising: forming a heat dissipation material seed at a position corresponding to the concave portion on the surface of the substrate; and forming the heat dissipation material portion by isotropically growing the seed; and patterning the heat dissipation material portion Then, the method includes a step of forming a convex portion corresponding to the shape of the concave portion, and a step of housing the convex portion in the concave portion and mounting the semiconductor laser element on the substrate.
By manufacturing in this way, a convex part with high heat dissipation can be reliably accommodated inside the concave part. Further, in the step of forming the convex portion, a gap can be formed between the convex portion and the concave portion by forming the shape of the convex portion smaller than the shape of the inner surface of the concave portion.

Moreover, the manufacturing method of the laser light source apparatus of this invention has the process of forming an insulating layer on the surface of the said convex part after the process of forming the said convex part.
By manufacturing in this way, the surface of the convex portion can be electrically insulated.

An image display device according to the present invention includes the laser light source device as described above, and a light modulation element that modulates laser light emitted from the laser light source device according to image information. .
Since such an image display device includes the laser light source device as described above, the heat dissipation and reliability of the device can be improved.

(Laser light source device)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the scale is appropriately changed for each layer and each member so that each layer and each member can be recognized on the drawing.
As shown in FIG. 1, the laser light source device 100 includes a semiconductor laser element 10 as a light source. The semiconductor laser element 10 is mounted on a substrate 20 having heat dissipation. The substrate 20 is made of, for example, aluminum nitride, diamond, silicon carbide, ceramic, or the like.

The semiconductor laser element 10 is formed by sequentially laminating an upper semiconductor layer 11 (InGaAs layer), a second mirror layer 12 (DBR layer), an active layer 13 and a first mirror layer 14 (DBR layer).
On the upper surface of the upper semiconductor layer 11, for example, an upper electrode 15 is formed of a conductive metal material such as nickel (Ni) or gold (Au). A plurality of openings 15a are formed in the upper electrode. The first mirror layer 14 is formed only in the portion corresponding to the opening 15a, and the lower semiconductor layer 16 (InGaAs layer) is formed in the other portion.

The first mirror layer 14 and the second mirror layer 12 are formed by alternately laminating a low composition layer and a high composition layer made of, for example, AlGaAs.
A region where the first mirror layer 14, the active layer 13, the second mirror layer 12, and the upper semiconductor layer 11 are stacked and the upper electrode 15 is opened constitutes the light emitting portion 10 a of the semiconductor laser element 10. The semiconductor laser element 10 includes a plurality of light emitting units 10a. In the light emitting unit 10a, the first mirror layer 14, the active layer 13, and the second mirror layer 12 constitute a vertical resonator.

A recess 17 reaching the upper semiconductor layer 11 from the lower semiconductor layer 16 is formed around the light emitting unit 10a. The cross-sectional shape of the recess 17 is formed in a substantially trapezoidal shape. The light emitting unit 10a is formed in a substantially trapezoidal cross-sectional shape on the substrate 20 side by a recess 17 formed around the light emitting unit 10a.
On the surface of the first mirror layer 14 and the lower semiconductor layer 16 on the substrate 20 side of the semiconductor laser element 10, a lower electrode 18 is formed of a conductive metal material such as nickel (Ni) or gold (Au). Has been. A lower electrode 18 is formed along a part of the inner surface 17a of the recess 17 in a part of the plurality of recesses 17 formed.

On the surface of the substrate 20 on the semiconductor laser element 10 side, a substrate-side electrode 21 is formed of a conductive metal material such as nickel (Ni) or gold (Au).
A convex portion 22 is formed on the surface of the substrate side electrode 21 at a position corresponding to the concave portion 17 of the semiconductor laser element 10. The convex portion 22 corresponds to the shape of the concave portion 17 and has a substantially trapezoidal cross-sectional shape. Further, the shape and size of the convex portion 22 are formed slightly smaller than the inner surface shape and size of the concave portion 17 so as to be accommodated in the concave portion 17. For example, when the width dimension W1 of the opening of the concave portion 17 on the substrate 20 side is about 200 μm and the depth dimension D1 is about 20 μm, the width dimension W2 of the convex portion 22 on the substrate 20 side is about 190 μm and the height dimension H2. Can be about 15 μm.

The convex portion 22 is formed of a material having high thermal conductivity such as copper (Cu), for example. In addition, an insulating layer 23 is formed on the surface of the convex portion 22 by, for example, silicon dioxide (SiO ₂ ).
The semiconductor laser element 10 is mounted on the substrate 20 so that a gap G is formed between the inner surface 17a of the concave portion 17 and the insulating layer 23 on the surface of the convex portion 22, and the lower electrode 18 and the substrate side electrode 21 are mounted. And are electrically connected.

Next, the operation of this embodiment will be described.
As shown in FIG. 1, when the upper electrode 15 and the substrate-side electrode 21 are connected to a power source (not shown) and a current is supplied to the semiconductor laser element 10, the active layer 13 of the light emitting unit 10a emits light of a specific wavelength. . The light emitted from the active layer 13 resonates and is amplified by a vertical resonator constituted by the first mirror layer 14, the active layer 13 and the second mirror layer 12, and is emitted from the second mirror layer 12 as laser light. . Laser light emitted from the second mirror layer 12 passes through the upper semiconductor layer 11 and is emitted to the outside from the opening 15 a of the upper electrode 15.

Here, a plurality of light emitting portions 10 a are formed in the semiconductor laser element 10. Therefore, compared with the case where the number of the light emitting units 10a is single, more current can be supplied to the laser light source device 100, and the output of the laser light source device 100 can be increased.
In addition, a recess 17 reaching the upper semiconductor layer 11 from the surface of the lower semiconductor layer 16 is formed around the light emitting unit 10a. Thereby, the active layer 13 can be separated and the directivity of the laser light emitted from the light emitting unit 10a can be enhanced.

When a current is supplied to the laser light source device 100, laser light is emitted from the light emitting unit 10a, while energy other than the light emission efficiency is converted into thermal energy, and the temperatures of the semiconductor laser element 10 and the substrate 20 are increased.
Here, since the convex portion 22 corresponding to the shape of the concave portion 17 is accommodated in the concave portion 17, the radiant heat of the semiconductor laser element 10 is absorbed by the convex portion 22, and the heat generated in the semiconductor laser element 10 is absorbed by the substrate 20. Can be diffused. In particular, since the concave portion 17 is formed around the light emitting portion 10a, the heat dissipation of the light emitting portion 10a that generates the most heat can be improved.

Therefore, according to the present embodiment, a large amount of heat generated in the semiconductor laser element 10 as the output of the laser light source device 100 is increased is reliably absorbed by the convex portion 22 and diffused to the substrate 20. The heat dissipation between the laser element 10 and the substrate 20 can be reliably improved.
Further, since the insulating layer 23 is formed on the surface of the convex portion 22, the lower electrode 18 and the convex portion 22 formed on the inner surface 17 a of the concave portion 17 are electrically insulated, and the lower electrode 18 and the convex portion 22 are electrically insulated. Can prevent short circuit.

Further, when the temperature of the semiconductor laser element 10 and the substrate 20 rises due to the supply of electric power, the difference between the thermal expansion coefficients between the semiconductor laser element 10 and the substrate 20 causes the inner surface 17a of the concave portion 17 and the surface of the convex portion 22 to be different. The distance to the insulating layer 23 varies.
Here, a gap G is formed between the concave portion 17 and the convex portion 22. Due to this gap G, variation in the distance between the concave portion 17 and the convex portion 22 due to the difference in expansion coefficient between the semiconductor laser element 10 and the substrate 20 can be received. For this reason, it can prevent that the convex part 22 contacts the recessed part 17 and stress acts on both the board | substrate 20 and the semiconductor laser element 10. FIG.

  Therefore, according to the present embodiment, due to the difference in thermal expansion coefficient between the substrate 20 and the semiconductor laser element 10, stress is generated in the substrate 20 and the semiconductor laser element 10 even when they have different thermal expansions. Can be prevented.

(Laser light source device manufacturing method)
Next, a manufacturing method of the laser light source device 100 of the present embodiment will be described.
As shown in FIG. 2A, first, the substrate side electrode 21 is formed on the surface of the substrate 20. The substrate-side electrode 21 is formed by vapor deposition using a conductive material such as nickel (Ni) or gold (Au).
Next, as shown in FIG. 2B, a heat dissipation material layer 220 is formed on the surface of the substrate side electrode 21. The heat dissipation material layer 220 is formed of a material having a higher thermal conductivity than air, such as copper (Cu). The heat dissipation material layer 220 is formed by, for example, plating.

  Next, the heat dissipating material layer 220 is patterned by, for example, a photolithography method, an etching method, or the like, and as shown in FIG. 3A, a position corresponding to the concave portion 17 of the semiconductor laser element 10 mounted on the substrate 20 (FIG. 3 (c)), the convex portion 22 is formed. The convex portion 22 is accommodated in the concave portion 17 when the semiconductor laser element 10 is mounted, and the concave portion 17 is formed so that a gap G (see FIG. 1) is formed between the inner surface 17a of the concave portion 17 and the surface of the convex portion 22. 17 is formed to have a size smaller than the size of the inner surface 17a.

Next, as shown in FIG. 3B, an insulating layer 23 is formed on the surface of the convex portion 22 by, for example, a mask sputtering method using an insulating material such as silicon dioxide (SiO ₂ ).
Next, as shown in FIG. 3C, the convex portion 22 is accommodated in the concave portion 17, the lower electrode 18 of the semiconductor laser element 10 and the substrate side electrode 21 are joined, and the semiconductor laser element 10 is mounted on the substrate 20. To do. The lower electrode 18 and the substrate-side electrode 21 are joined by, for example, solder using fluxless Au—Sn (gold tin), Sn—Ag—Cu, In (indium), or the like.

  As explained above, according to the manufacturing method of this embodiment, the convex part 22 with high heat dissipation can be reliably accommodated inside the concave part 17. Further, in the step of forming the convex portion 22, the gap G can be formed between the convex portion 22 and the concave portion 17 by forming the shape of the convex portion 22 smaller than the shape of the inner surface 17 a of the concave portion 17. . Further, the surface of the convex portion 22 can be electrically insulated by the insulating layer 23.

(Modification of manufacturing method of laser light source device)
Next, a modification of the method for manufacturing the laser light source device 100 of the present embodiment will be described with reference to FIGS. 4A and 4B with reference to FIGS. 3A to 3C. To do. The manufacturing method of the laser light source device 100 according to the present modification is the same as the manufacturing method of the laser light source device 100 described above, and instead of forming the heat dissipation material layer 220 on the surface of the substrate 20, an island-shaped heat dissipation material portion is formed on the surface of the substrate 20. The difference is that 222 is formed. Since the other points are the same as those of the method for manufacturing the laser light source device 100 described above, the same portions are denoted by the same reference numerals and description thereof is omitted.

As shown in FIG. 4A, after the substrate side electrode 21 is formed on the surface of the substrate 20, the thermal conductivity of, for example, copper (Cu) is formed at a position corresponding to the concave portion 17 on the surface of the substrate side electrode 21. The seed 221 is formed of a high material. For example, the seed 221 is formed by a mask vapor deposition method or the like.
Next, as shown in FIG. 4B, the seed 221 is isotropically grown by plating or the like to form an island-shaped heat radiation material portion 222. Next, the heat dissipating material part 222 is patterned by, for example, laser processing or the like to form the convex part 22 corresponding to the shape of the concave part 17 as shown in FIG. Then, similarly to the method of manufacturing the laser light source device 100 described in the above embodiment, as shown in FIGS. 3B and 3C, an insulating layer 23 is formed on the surface of the convex portion 22, The semiconductor laser element 10 is mounted on the substrate 20.

As described above, according to the method for manufacturing the laser light source device 100 in the present modification, the laser light source device 100 similar to the method for manufacturing the laser light source device 100 of the above-described embodiment can be manufactured.
Further, since the heat dissipation material portion 222 is formed only at a position corresponding to the recess 17, the heat dissipation material can be used more effectively than when the heat dissipation material layer 220 is formed on the surface of the substrate 20.

<Application example of laser light source device>
By applying the laser light source device 100 as described above to an image display device, it is possible to improve heat dissipation in these devices. Hereinafter, application examples to the image display device will be described.

[Application example: Projector]
A configuration of the projector 30 will be described as an example of an image display device to which the laser light source device 100 according to the above-described embodiment is applied. FIG. 5 is a schematic diagram showing an outline of the optical system of the projector 30.

  In FIG. 5, the projector 30 includes a laser light source device 100, a liquid crystal panel 32 as a light modulation device, polarizing plates 331 and 332, a cross dichroic prism 34, a projection lens 35, and the like. The liquid crystal light valve 33 is configured by the liquid crystal panel 32, the polarizing plate 331 provided on the light incident side, and the polarizing plate 332 provided on the light emission side.

  The laser light source device 100 includes a red light source device 100R that emits red laser light, a blue light source device 100B that emits blue laser light, and a green light source device 100G that emits green laser light. . These light source devices 100 (100R, G, B) are arranged so as to face the three side surfaces of the cross dichroic prism 34, respectively. In FIG. 5, the red light source device 100R and the blue light source device 100B face each other, and the projection lens 35 and the green light source device 100G face each other across the cross dichroic prism 34. The position can be changed as appropriate.

  The liquid crystal panel 32 uses, for example, a polysilicon TFT (Thin Film Transistor) as a switching element. The colored light emitted from each laser light source device 100 enters the liquid crystal panel 32 via the incident-side polarizing plate 331. The light incident on the liquid crystal panel 32 is modulated according to the image information and emitted from the liquid crystal panel 32. Of the light modulated by the liquid crystal panel 32, only specific linearly polarized light passes through the exit-side polarizing plate 332 and travels toward the cross dichroic prism 34.

The cross dichroic prism 34 is an optical element that combines color lights modulated by the liquid crystal panels 32 to form a color image. The cross dichroic prism 34 has a substantially square shape in plan view in which four right-angle prisms are bonded. Two kinds of dielectric multilayer films are provided in an X shape at the interface of these four right-angle prisms. These dielectric multilayer films reflect the color lights emitted from the liquid crystal panels 32 facing each other and transmit the color lights emitted from the liquid crystal panel 32 opposed to the projection lens 35. In this way, the color lights modulated by the liquid crystal panels 32 are combined to form a color image.
The projection lens 35 is configured as a combined lens in which a plurality of lenses are combined. The projection lens 35 enlarges and projects the color image V.

  As described above, by applying the laser light source device 100 according to the above-described embodiment to the projector 30, the heat dissipation of the light source of the projector 30 can be improved and the reliability can be improved.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the insulating layer is formed on the surface of the convex portion, but when there is no possibility of a short circuit due to wiring, such as when the wiring is not formed on the inner surface of the concave portion, the surface of the convex portion is insulated. It is not necessary to form a layer.

  The number of light emitting portions of the semiconductor laser element may be single. The lower electrode may not be formed on the substrate side of the semiconductor laser element, but may be directly bonded to the substrate side electrode by solder bonding or the like. The shape of the convex part and the concave part may not be the shape described in the above embodiment as long as the convex part is accommodated in the concave part. The convex portion may be formed of a material other than copper as long as it has a higher thermal conductivity than air.

It is sectional drawing of the laser light source apparatus which concerns on embodiment of this invention. (A) And (b) is process explanatory drawing of the manufacturing method of the laser light source apparatus of FIG. (A)-(c) is process explanatory drawing of the manufacturing method of the laser light source apparatus of FIG. (A) And (b) is process explanatory drawing of the modification of the manufacturing method of the laser light source apparatus of FIG. It is a schematic block diagram of the optical system of the projector which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Semiconductor laser element, 10a Light emission part, 17 Concave part, 17a Inner surface, 18 Lower electrode (electrode), 20 Substrate, 22 Convex part, 23 Insulating layer, 30 Projector (image display apparatus), 32 Liquid crystal panel (light modulation element), 100 laser light source device, 220 heat dissipation material layer, 221 seed, 222 heat dissipation material portion, G gap

Claims (8)

A laser light source device comprising a semiconductor laser element and a substrate on which the semiconductor laser element is mounted, wherein a recess is formed on a surface of the semiconductor laser element on the substrate side,
A convex portion accommodated in the concave portion is formed at a position corresponding to the concave portion of the substrate,
The convex portion is formed of a material having a higher thermal conductivity than air,
A laser light source device, wherein a gap is formed between the semiconductor laser element and the convex portion.   2. The laser light source device according to claim 1, wherein the concave portion is formed around a light emitting portion of the semiconductor laser element.   3. The laser light source device according to claim 1, wherein a plurality of the light emitting portions are formed in the semiconductor laser element. 4. In the recess, an electrode is formed along at least a part of the inner surface of the recess,
The laser light source device according to claim 1, wherein an insulating layer is formed on a surface of the convex portion. A method of manufacturing a laser light source device, comprising: a semiconductor laser element; and a substrate on which the semiconductor laser element is mounted, wherein a recess is formed on a surface of the semiconductor laser element on the substrate side,
Forming a heat dissipation material layer on the surface of the substrate with a material having a higher thermal conductivity than air; and
Patterning the heat dissipating material layer and forming a convex portion at a position corresponding to the concave portion;
Accommodating the convex portion in the concave portion, and mounting the semiconductor laser element on the substrate;
A method of manufacturing a laser light source device, comprising: A method of manufacturing a laser light source device, comprising: a semiconductor laser element; and a substrate on which the semiconductor laser element is mounted, wherein a recess is formed on a surface of the semiconductor laser element on the substrate side,
Forming a seed of a heat dissipation material at a position corresponding to the recess on the surface of the substrate, and forming the heat dissipation material portion by isotropically growing the seed;
Patterning the heat dissipating material part to form a convex part corresponding to the shape of the concave part;
Accommodating the convex portion in the concave portion, and mounting the semiconductor laser element on the substrate;
A method of manufacturing a laser light source device, comprising:   The method of manufacturing a laser light source device according to claim 5, further comprising a step of forming an insulating layer on a surface of the convex portion after the step of forming the convex portion. The laser light source device according to any one of claims 1 to 4,
A light modulation element that modulates laser light emitted from the laser light source device according to image information;
An image display device comprising:

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