JPH0548213A - Sub-mount for semiconductor laser - Google Patents

Abstract

PURPOSE:To reduce manhours when assembling, by providing a through hole in a sub-mount, and by connecting electrically a semiconductor laser oscillation element with a heat sink, and further, by making bondings by wires and barrel coatings unnecessary. CONSTITUTION:In a sub-mount 7 made of an insulation material, which is located between a semiconductor laser oscillation element 3 and a heat sink 4, a through hole 6 is provided. By the metallized layer formed on the inner surface of the through hole 6, the semiconductor laser oscillation element 3 makes continuity with the heat sink 4, which are provided respectively on both surfaces of the sub-mount 7. Thereby, bondings by wires are made unnecessary, and manhours when assembling are reduced, and further, the generations of faulty continuity caused by the disconnections of wires are eliminated. Also, on a machining process, a dicing-cut is performed in a final process. Therefore, machining can be treated in the state of an AlN base board, and it is facilitated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate for mounting an oscillation element of a semiconductor laser on a heat sink made of Cu and having an Au plating on its surface. The substrate has good conductivity and good thermal conductivity. The present invention relates to a submount of a semiconductor laser having a function having both.

[0002]

2. Description of the Related Art One of conventional semiconductor laser submounts is a sputtering method in which Ti / Pt / Au or Cr / Ni / Au or the like is sputtered on both sides of an AlN substrate 1 shown in FIG. The metallized layer 2 is formed by coating, and then a dicing cut is performed to a predetermined size as shown in FIG. 8, and then the laser oscillation element 3 is formed on one surface as shown in FIG.
The heat sink 4 was bonded to the other side by soldering or the like. Since the AlN substrate 1 itself is not conductive and the peripheral surface is not conductive due to the dicing cut, the surfaces of the metallized layer 2 and the heat sink 4 of the AlN substrate 1 on the laser oscillation element 3 side are covered with the wire 5 as shown in FIG. It was bonded and made conductive. Another one of the conventional semiconductor laser submounts not wire-bonded is a sputtering method or a vacuum deposition method after dicing the AlN substrate 1 shown in FIG. 11 to a predetermined size as shown in FIG. Barrel-coat Ti / Pt / Au with a metallized layer 2 on the entire circumference of the submount as shown in FIG. 13. Next, as shown in FIG. 14, a laser oscillator 3 is provided on one side and a heat sink 4 is provided on the other side. Was bonded with solder or the like, and the metallized layer 2 was used for electrical conduction.

By the way, in the former case, the wire 5 may be broken, and it is necessary to secure a space for bonding the wire 5. Breakage of the wire 5 lowers reliability, and securing a space hinders miniaturization. In the latter case, the barrel coating after dicing and cutting the AlN substrate 1 is troublesome.
In addition, it is necessary to clean and dry the chips that have been cut by dicing, and the handling of the separated chips becomes very troublesome.

[0004]

SUMMARY OF THE INVENTION Therefore, the present invention is intended to provide a semiconductor laser submount capable of establishing electrical continuity between a laser oscillator and a heat sink without wire bonding or barrel coating. is there.

[0005]

A submount of a semiconductor laser according to the present invention for solving the above-mentioned problems is a semiconductor laser including a semiconductor laser oscillator, a heatsink and a submount of an insulating material located between the two. In this case, a through hole is provided in the submount, and a metallization layer is formed on the inner surface of the through hole to establish electrical continuity between the semiconductor laser oscillator and the heat sink.

[0006]

As described above, in the semiconductor laser submount according to the present invention, the through holes are provided, and the semiconductor laser oscillation elements on both sides are electrically connected to the heat sink by the metallized layers formed on the inner surfaces of the through holes. Is unnecessary, and the number of man-hours at the time of assembly is reduced and the occurrence of defective conduction due to wire breakage is eliminated. In addition, since the dicing cut is performed in the final step in the processing step, it can be handled in the state of the AlN substrate until the end, and the processing becomes easy.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a semiconductor laser submount according to the present invention and a conventional example will be described. First, an example will be described. A length of 75 mm, a width of 75 mm, and a thickness of 0.3 mm shown in FIG.
As shown in FIG. 2, 4900 through holes 6 having a diameter of 0.1 mm were bored at a 1 mm pitch by laser processing on an AlN substrate 1 having a mirror finish (surface roughness Ra 1000 Å). Next, as shown in FIG. 3, RF 500W is applied to both front and back surfaces of the AlN substrate 1.
Ti (1000Å) after sputter etching for 3 minutes
/ Pt (3000Å) / Au (2000Å) sputter method (DC
1 KW) to form the metallized layer 2 and also to coat the inner surface of the through hole 6 to form the metallized layer 2 so that electrical conduction can be established between the front and back surfaces. The sputtering process at this time was DC1KW for Ti, Pt, and Au, respectively.
And the ultimate vacuum is 5 × 10 ⁻⁶ Torr, Ar gas pressure is 3 ×
It is 10 ^-3 Torr. Then this surface and through hole 6
As shown in FIG. 4, the AlN substrate 1 having the metallized layer 2 formed on the inner surface thereof was cut into a square of 1.0 mm on each side with one through hole 6 placed at the center with a dicer to form a submount 7. As shown in FIG. 5, the submount 7 was bonded to the surface of the heat sink 4 with AuSn 20 wt% solder, and the laser oscillator 3 was bonded to the surface of the submount 7 with AuSn 20 wt% solder.

On the other hand, to explain the conventional example, as shown in FIG. 7, the same Ti (1000Å) / Pt (3000Å) / Pt (3000Å) /
Au (2000Å) is coated by a sputtering method to form a metallized layer 2, and then, as shown in FIG. 8, a dicer is used to cut a square with a side of 1.0 mm to form a submount, and then as shown in FIG. AuS on the surface of the heat sink 4
Bonding with n20wt% solder, laser bonding element 3 is bonded to the surface of the submount with AuSn20wt% solder, and then the metallization layer 2 of the AlN substrate 1 on the laser oscillation element 3 side is bonded as shown in FIG. Then, an Au wire 5 having a diameter of 50 μm was bonded to the surface of the heat sink 4 to establish conduction.

However, when the resistance values were measured at the positions of the upper surface of the submount of each of these 100 semiconductor lasers and the upper surface of the heat sink, the average resistance value of the conventional example was 0.1Ω.
In contrast, there were two conductive breakdowns in which the Au wire 5 was broken, whereas in the example, the average resistance value was 0.06Ω and no conductive breakdown was observed.

[0010]

As described above, in the semiconductor laser submount of the present invention, the through hole is provided, and the metallization layer is formed on the inner surface of the through hole to establish the conduction between the laser oscillation element and the heat sink on both sides. There is no need for wire bonding, and no barrel coating is required, reducing the number of steps during assembly,
Conduction failure due to wire breakage is eliminated. In addition, since the dicing cut is performed in the final step in the processing step, it can be handled in the state of the AlN substrate until the end.
It is possible to obtain stable quality and performance.

[Brief description of drawings]

FIG. 1 is a diagram showing a manufacturing process of an embodiment of a semiconductor laser submount according to the present invention.

FIG. 2 is a diagram showing a manufacturing process of an embodiment of a semiconductor laser submount according to the present invention.

FIG. 3 is a diagram showing a manufacturing process of an embodiment of a semiconductor laser submount according to the present invention.

FIG. 4 is a diagram showing a manufacturing process of an embodiment of the semiconductor laser submount according to the present invention.

FIG. 5 is a diagram showing a manufacturing process of an embodiment of the semiconductor laser submount according to the present invention.

FIG. 6 is a diagram showing a manufacturing process of an example of a conventional semiconductor laser submount.

FIG. 7 is a diagram showing a manufacturing process of an example of a conventional semiconductor laser submount.

FIG. 8 is a diagram showing a manufacturing process of an example of a conventional semiconductor laser submount.

FIG. 9 is a diagram showing a manufacturing process of an example of a conventional semiconductor laser submount.

FIG. 10 is a diagram showing a manufacturing process of an example of a conventional semiconductor laser submount.

FIG. 11 is a diagram showing a manufacturing process of another example of the conventional semiconductor laser submount.

FIG. 12 is a diagram showing a manufacturing process of another example of the conventional semiconductor laser submount.

FIG. 13 is a diagram showing a manufacturing process of another example of the conventional semiconductor laser submount.

FIG. 14 is a diagram showing a manufacturing process of another example of the conventional semiconductor laser submount.

[Explanation of symbols]

1 AlN substrate 2 Metallized layer on both upper and lower surfaces of AlN substrate and through hole inner surface 3 Laser oscillator 4 Heat sink 6 Through hole 7 Submount

Claims (1)

[Claims] 1. A semiconductor laser comprising a semiconductor laser oscillator, a heat sink, and a submount made of an insulating material located between the two, wherein a through hole is provided in the submount, and a metallized layer is formed on an inner surface of the through hole. The semiconductor laser submount is characterized in that the semiconductor laser oscillator and the heat sink are electrically connected.