JPH0140514B2 - - Google Patents

Abstract

PURPOSE:To enable to braze a semiconductor laser chip to an Si sub mount and a metallic block at the same time by a method wherein an Au plated film is provided previously on the main surface whereon the semiconductor laser chip is enabled to be brazed. CONSTITUTION:The Si sub mount 1' is mounted on the Ag block 3, and the semiconductor laser chip 2' is mounted on the sub mount 1'. Au plated films 15-17 are formed respectively on the brazing surfaces of the sub mount 1' and the laser chip 2'. When these elements successively mounted are heated, the platings 15-17 on each junction surface fuse, resulting in connection each other. Thereby, the semiconductor laser element, Si sub mount, and metallic block can be brazed at the same time; therefore the yield of the laser device and the workability of the manufacture can be contrived to improve.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a semiconductor laser device.

Semiconductor laser chips are soldered to a block made of silver or the like in order to improve the dissipation of heat generated during operation and to facilitate handling. When considering reliability, it is best to use gold or silicone brazing material as this brazing material. However, since the gold/silicon brazing material is hard, if the chip is brazed directly to the block via the gold/silicon brazing material, the chip is likely to become distorted due to the difference in thermal expansion coefficient between the chip and the block, resulting in laser characteristics. tends to get worse. To prevent this, a method is often used in which a silicon plate (hereinafter referred to as a silicon submount) is sandwiched between the chip and the block and brazed.

In the conventional brazing of the chip, silicon submount, and block, as shown in FIG.
As shown in Figure b, silicon 12, which is the material of silicon submount 1, was placed in a nitrogen atmosphere at 430°C.
A gold-silicon brazing material 13 is formed by the eutectic of gold 11 plated with
The semiconductor laser chip 2 and the silicon submount 1 are brazed by grasping the perpendicular surface 7 with tweezers and rubbing it against the silicon submount 1 in the gold-silicon brazing material 13, and then brazing the semiconductor laser chip 2 and the silicon submount 1 as shown in FIG.
As shown in the figure, a silver block 3 is placed in a nitrogen atmosphere at 430°C, and a gold/silicon brazing material 14 is melted at the position of the silver block 3 to be brazed. The silicon submount 1 and the silver block 3 are brazed together by rubbing the gold onto the silver block 3 in a gold/silicon brazing material 14.

However, such conventional brazing methods have the following drawbacks.

1 When brazing the chip 2 and the silicon submount 1, the chip 2 is attached to the silicon submount 1 in the gold-silicon brazing material 13 formed by eutectic, grasping the surface 7 perpendicular to the cavity surface. Because of the rubbing, the solder metal tends to adhere to the chip 2 and the surface 7 of the chip 2 perpendicular to the resonator surface is easily damaged.
Therefore, the characteristics of the semiconductor laser may deteriorate.

2 When brazing silicon submount 1 to silver block 3, first attach silicon submount 1 to silver block 3.
Chip 2 is brazed onto the silicon submount 1 at the same temperature as the brazing material to the silver block 3 of
may move.

The present invention was made in order to eliminate the drawbacks of the conventional brazing method for semiconductor laser devices. The silicon submount on which it is mounted is placed on a metal block so that the gold-plated surfaces are in contact with each other, and the semiconductor laser element, silicon submount, and metal block are simultaneously brazed to create a semiconductor laser device with good yield and workability. A manufacturing method is provided.

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIG.

FIG. 2a is a sectional view of a silicon submount used for soldering a semiconductor laser according to an embodiment of the present invention. 1 in the figure is a silicon submount, 1
2 is silicon with a thickness of 300 μm, and 15 is a 1-6 μm film adhered to the surface to which the semiconductor laser chip is to be brazed.
The gold plating film 16 has a thickness of 10 to 20 μm and is applied to the surface to be brazed to the silver block. 1' is a silicon submount consisting of the above-mentioned 12, 15, and 16. For brazing, first place the silicon submount 1' on a predetermined position on the silver block 3 in a nitrogen atmosphere at 200°C, and then place the silicon submount 1' on a predetermined position on the submount 1' as shown in FIG. 1~ on the surface to be brazed
A semiconductor laser chip 2' having a gold plating film 17 with a thickness of 3 μm is mounted, and the silver block 3, submount 1', and semiconductor laser chip 2' are fixed. Next, a load of, for example, 20 g is aligned and fixed on top of the semiconductor laser chip 2',
While adding silicon submount 1' and silver block 3, the temperature was increased in a nitrogen/hydrogen mixed gas atmosphere.
The temperature is raised to 430°C, and the gold 16 plated on the silicon submount, or the gold 15 plated on the silicon submount and the gold 17 plated on the semiconductor laser chip 2' are eutectic with the silicon of the silicon submount 1'. the second formed by
As shown in Figure c, gold/silicon brazing filler metals 18, 19
As a result, the silver block 3 and the silicon submount 1' and the silicon submount 1' and the semiconductor laser chip 2' are simultaneously brazed. When the temperature is raised, a gold/silicon brazing material 18 of about 20 μm is formed on the surface of the silicon submount 1' in contact with the silver block 3, but this gold/silicon brazing material 18 spreads over the silver block 3 due to the load. At the same time, the silicon submount 1' sinks by more than ten μm due to the melted gold/silicon brazing material 18, and the silver block 3
and submount 1' are bonded well.
On the other hand, the adhesion between the semiconductor laser chip 2' and the submount 1' is also performed well because the silicon of the submount 1' and the gold 17 plated on the semiconductor laser chip 2' are eutectic.

According to the method of one embodiment of the present invention, since the gold plating film 17 is provided in advance on the main surface of the semiconductor laser chip 2' to be brazed, the surface of the brazed portion of the semiconductor laser chip 2' is not oxidized. Therefore, there is no need to rub the semiconductor laser chip 2' onto the silicon submount 1' while brazing it.
The semiconductor laser chip 2', the silicon submount 1' and the silver block 3 can be brazed together. That is, since the semiconductor laser chip 1' is not gripped while the filler metal is melted at the same time, the filler material may adhere to the resonator surface 6 of the semiconductor laser chip 1' and the surface 7 perpendicular thereto, or damage this surface. Therefore, the characteristics of the semiconductor laser will not deteriorate. Further, since the semiconductor laser chip 2', the silicon submount 1' and the silver block 3 are brazed at the same time, there is no problem of the semiconductor laser chip 2' moving during brazing.

Although a silver block was used as the block in this embodiment, a copper block plated with silver or gold may also be used.

As described above, according to the present invention, semiconductor laser devices are mounted on a silicon submount so that their gold-plated surfaces are in contact with each other, and the silicon submount on which the semiconductor laser devices are mounted is mounted so that the gold-plated surfaces are in contact with each other. Since the semiconductor laser element, the silicon submount, and the metal block can be mounted on a metal block and brazed at the same time, it has the excellent effect of improving the yield and manufacturing workability of the semiconductor laser device.

[Brief explanation of drawings]

1A to 1C are step-by-step sectional views showing a conventional brazing method for a semiconductor laser device, and FIGS. 2A to 2C are step-by-step sectional views showing a brazing method according to an embodiment of the present invention. In the figure, 1' is a silicon submount, 2' is a semiconductor laser chip, 3 is a silver block, 15 and 16 are gold plating films deposited on the silicon submount,
17 is a gold plating film attached to the chip, 18 is a silicon submount and a gold/silicon brazing material formed of gold crystals attached to it, and 19 is a silicon submount and attached to this. This is a gold/silicon brazing material made of gold and a gold eutectic deposited on a chip. The same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A step of gold plating one main surface of a semiconductor laser element, a step of gold plating each of both main surfaces of a silicon submount to which this semiconductor laser element is mounted, and a step of gold plating the silicon submount. The semiconductor laser elements are placed on top so that their gold-plated surfaces are in contact with each other, and the silicon submount on which the semiconductor laser elements are placed is placed on a metal block so that the gold-plated surfaces are in contact with each other. A method for manufacturing a semiconductor laser device including a step of simultaneously brazing a submount and a metal block. 2. The method of manufacturing a semiconductor laser device according to claim 1, wherein the plating thickness of the silicon submount on the side in contact with the metal block is 10 to 20 μm.