JPH08228044A - Mount structure of semiconductor laser - Google Patents

Abstract

PURPOSE: To bring about a high efficient heat radiating effect in this mount structure of semiconductor laser. CONSTITUTION: The first flat plate type submount 6 fixed on a heat sink 11 and a semiconductor laser chip 10 mounted on the first submount 6 are contained and held by recessions formed by anisotropical etching step of the second submount 3 and then the first and second submounts 6 and 3 are mutually fixed together by fusion welding step. Through these procedures, the operational heat can be radiated from both surfaces of this semiconductor laser chip 10 simultaneously eliminating the heat sink to be provided on both sides of this semiconductor chip 10 as well as suppressing the thickness to the utmost thereby enabling the compactness of the semiconductor element to be enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser mounting structure, and more particularly to a semiconductor laser mounting structure for dissipating heat during operation of the semiconductor laser.

[0002]

2. Description of the Related Art In a semiconductor laser in which voltages are applied to opposite sides of a block-shaped semiconductor laser chip to extract laser light from the side surfaces thereof, heat is dissipated during operation of the semiconductor laser chip. It uses a heat sink.

Conventionally, for example, in one disclosed in Japanese Patent Laid-Open No. 60-81884, a semiconductor laser chip 1 is used.
The surface was joined to a heat sink (heat radiator) via a submount, and a bonding wire was connected to the other opposite surface to apply a voltage to both surfaces. According to this structure, the heat dissipation effect from the surface in contact with the submount is high, but the heat dissipation effect on the opposite surface is low.

Further, Japanese Patent Laid-Open No. 1-181490 discloses that
Submounts are bonded to opposite sides of the semiconductor laser chip, respectively. According to this structure, heat can be radiated from both sides of the semiconductor laser chip, but heat sinks are laminated on each submount,
Not only is there a problem that the semiconductor laser chip becomes thicker on both sides to make the device larger, but also leads are connected to each submount, which complicates the structure.

[0005]

SUMMARY OF THE INVENTION In view of the above problems of the prior art, a main object of the present invention is to provide a mount structure for a semiconductor laser which can obtain a highly efficient heat dissipation effect with a simple structure. is there.

[0006]

According to the present invention, a flat plate-shaped first submount fixed to a heat sink and a semiconductor laser mounted on the first submount are provided. A second submount formed with a recess capable of receiving a chip, and sandwiching the semiconductor laser chip between the first submount and the bottom surface of the recess of the second submount. It is achieved by providing a mounting structure for a semiconductor laser, characterized in that the second submount is fixed on the first submount.

[0007]

By doing so, the semiconductor laser chip is
Since the structure is sandwiched by the second submount, the operating heat can be dissipated from both sides of the semiconductor laser chip, and the semiconductor laser chip can be received by the recess of the second submount. Since the submount is fixed onto the first submount, the heat transferred to the second submount can be transferred to the heat sink via the first submount and can be dissipated.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

1 to 4 show a manufacturing process of a first embodiment of a semiconductor laser mount structure to which the present invention is applied. First, as shown in FIG. 1A, a plurality of masks 2 for chemical etching are formed at intervals on the upper surface of a flat Si material 1 having a crystal structure (100) in the figure by patterning. When anisotropic etching is performed on the Si material 1 of FIG. 1A, a concave portion 1a having an inverted trapezoidal cross-sectional shape and a convex portion 1b are formed as shown in FIG. 1B. Then, by removing the mask 2, the second
The submount 3 is formed as shown in FIG.

Then, as shown in FIG.
The metal electrode 4 is formed on the surfaces of the concave portion 1a and the convex portion 1b of the submount 3 so as to cover the entire surface. The metal electrode 4
Solder 5 is formed in layers on the bottom surface corresponding to the concave portion 1a and the top surface corresponding to the protruding end surface of the convex portion 1b, as shown in FIG. 2B. In this way, the second submount 3 is formed as shown in FIG. 2C showing a partial perspective view thereof.

Next, the first submount 6 made of an insulating material.
Shows the structure of. The first submount 6 is the same as that shown in FIG.
As shown in FIG. 3A showing the portion corresponding to the second submount 3 shown in FIG. 3C, the strip-shaped metal electrodes 7a, 7b, and 7c are provided on one surface of the insulating plate-shaped body. The metal electrodes 7a, 7b, 7c are formed at a predetermined interval.
The bonding pads 8a, 8b, 8c are formed on the upper surfaces of the respective one ends in the longitudinal direction of the above, and the solder 9 is patterned on the upper surface of the other end in the longitudinal direction of the intermediate metal electrode 7b.

Next, as shown in FIG. 3B, the semiconductor laser chip 10 is placed on the solder 9 of the first submount 6 having the above-mentioned structure, and the solder 9 is fused to the semiconductor laser chip. 10 is fixed to the first submount 6. Further, as shown in FIG. 3C, the second submount 3 is placed on the first submount 6 so as to receive the semiconductor laser chip 10 in the concave portion 1a, and the solder 5 is placed thereon. By fusion bonding, both submounts 3 and 6 are fixed to each other and integrated.

As shown in FIG. 4A, the bottom surface of the first submount 6 (the surface to which the second submount 3 is fixed is formed on the solder 12 formed in layers on the heat sink 11). Are placed on the heat sink 11 and the solder 12 is fused to fix the first submount 6 on the heat sink 11. Also, each bonding pad 8a, 8b,
Connect the lead wire to 8c. The melting point of the solder 9 is the highest, the melting point of the solder 5 is the second highest, and the melting point of the solder 12 is the lowest.

FIG. 4B shows a cross section of the semiconductor laser device thus configured (a cross section taken along line IVb-IVb in FIG. 4A). As shown in FIG. 4 (b), the semiconductor laser chip 10 is sandwiched between the first submount 6 made of an insulator and the recess 1a of the second submount 3 formed by chemical etching. Therefore, the heat generated during the operation can be dissipated from the two end faces of the semiconductor laser chip 10 through the respective submounts 3 and 6. Further, as described above, the number of times of solder fusion is small. Further, since the contact is made from the main surface (each bonding pad 8a, 8b, 8c) of the first submount 6, it is possible to avoid a complicated wiring structure and preferably prevent disconnection.

Next, referring to FIG. 5 and FIG. 6, the second embodiment of the present invention will be described.
An example of is shown. The same parts as those in the above embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. Further, the second submount 3 is formed in the same manner as in the above-mentioned embodiment, so its illustration and description will be omitted.

The first submount 13 is shown in FIG.
As shown in (a), its main surface (upper surface in the figure)
An insulating film 14 is formed on the entire surface of the metal film, and strip-shaped metal electrodes 7a, 7b, and 7c are formed on the insulating film 14 in a portion corresponding to the second submount 3 as in the above-described embodiment. Bonding pads 8a, 8b, 8c are formed on the upper surfaces of the one ends in the longitudinal direction of 7a, 7b, 7c, respectively, and solder 9 is formed on the upper surface of the other end of the intermediate metal electrode 7b in the longitudinal direction by patterning. Has been done. Next, as shown in FIG. 5B, the semiconductor laser chip 10 is placed on the solder 9, and the solder 9 is fused to fix the semiconductor laser chip 10 to the first submount 13.
Then, as shown in FIG. 5C, the second submount 3 is mounted on the first submount 13 so as to receive the semiconductor laser chip 10 in the recess 1a, as shown in FIG. Then, the solder 5 is fused and the submounts 3 and 13 and the upper surface of the semiconductor laser chip 10 and the second submount 3 are fixed and integrated with each other.

Then, the solder 12 formed in layers on the heat sink 11 is fused to form the first submount 13
The bottom surface of the is fixed on the heat sink 11 (see FIG. 6).
(A)). Also, each bonding pad 8a, 8b,
Connect the lead wire to 8c. Also in this second embodiment, as shown in FIG.
Since the semiconductor laser chip 10 is sandwiched between the first submount 13 and the recess 1a of the second submount 3 formed by chemical etching, the heat generated during the operation of the semiconductor laser chip 10 is generated. It is possible to dissipate the light from the two end faces via the submounts 3 and 13, and to obtain the same effect as that of the above-described embodiment. Even if the first submount 13 is a conductor, since the gold electrodes 7a, 7b, and 7c are electrically insulated by the insulating film 14, the voltage applied to both sides of the semiconductor laser chip 10 is not affected. There is no inconvenience.

[0018]

As described above, according to the present invention, the semiconductor laser chip is held between the first and second submounts regardless of whether the first submount is a conductor or an insulator. , The operating heat can be dissipated from both sides of the semiconductor laser chip, and the heat transmitted to the second submount is transmitted to the heat sink via the first submount to be dissipated, so that both sides of the semiconductor laser chip can be dissipated. It is not necessary to provide a heat sink on the substrate, the thickness can be suppressed as much as possible, and the size reduction of the semiconductor laser device can be improved. Further, since the semiconductor laser chip is received by the concave portion of the second submount, the semiconductor laser chip can be positioned only by fixing the both submounts.

[Brief description of drawings]

FIG. 1A is a partial front view showing a state in which a mask for chemical etching is formed to form a second submount, and FIG. 1B is a portion showing a shape after anisotropic etching. It is a front view, (c) is a partial front view which shows the state which removed the mask after etching.

2A is a partial front view showing a state in which a metal electrode is formed on the second submount, FIG. 2B is a partial front view showing a state in which solder is further formed, and FIG. The principal part perspective view corresponding to (b).

FIG. 3A is a perspective view of a main part showing a first submount, FIG. 3B is a perspective view of a main part showing a state in which a semiconductor laser chip is fixed to the first submount, and FIG. FIG. 7A is a perspective view of a main part showing a state in which the second submount is fixed to the first submount.

FIG. 4A is a perspective view of a main part showing a state in which a submount is fixed to a heat sink, and FIG. 4B is a IVb of FIG.
-A sectional view taken along line IVb.

5A and 5B are views showing a second embodiment, FIG. 5A is a perspective view of an essential part showing a first submount, and FIG. 5B is a state in which a semiconductor laser chip is fixed to the first submount. FIG. 4C is a perspective view of relevant parts showing a state where the second submount is fixed to the first submount.

FIG. 6 is a view showing a second embodiment, (a) is a perspective view of a main part showing a state where a submount is fixed to a heat sink, and (b) is a view taken along line VIb-VIb of (a). Cross-section view.

[Explanation of symbols]

 1 Si Material 1a Recess 1b Convex 2 Mask 3 Second Submount 4 Metal Electrode 5 Solder 6 First Submount 7a, 7b, 7c Metal Electrode 8a, 8b, 8c Bonding Pad 9 Solder 10 Semiconductor Laser Chip 11 Heat Sink 12 solder 13 first submount 14 insulating film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Fujii 5-10-1 Fuchinobe, Sagamihara City Nippon Steel Corp. Electronics Research Laboratories

Claims (1)

[Claims] 1. A flat plate-shaped first member fixed to a heat sink.
And a second submount formed with a recess capable of receiving the semiconductor laser chip mounted on the first submount, the semiconductor laser chip being mounted on the first submount. A mounting structure for a semiconductor laser, wherein the second submount is fixed on the first submount so as to be sandwiched between the second submount and the bottom surface of the recess of the second submount.