JPS6323386A - Method for assemblying semiconductor laser - Google Patents

Abstract

PURPOSE:To prevent part of laser light from being reflected on the surface of a bonding agent by a method wherein a protrusion part having a width slightly wider than the width of a semiconductor laser element in the laser light emitting direction is formed on the upper surface of a heat dissipation substrate and the semiconductor laser element is thermally fixed by pressure on the protrusion part using the bonding agent. CONSTITUTION:A protrusion part 5, which has a width W slightly wider than the width P of a semiconductor laser element 2 and has a height of H, is formed on the upper surface of a heat dissipation substrate consisting of Cu, for example. That is, when an In piece, a little excessive in amount, to be used as a bonding agent 3 is placed on the protrusion part 5 and heated, the In piece is fused on the whole upper surface of the protrusion part, becomes highest at the central part by surface tension at that time and the form of a prescribed curved surface can be obtained. Then, the semiconductor laser element 2 is placed on the bonding agent 3 which has been formed and solidified in a protuberance with a prescribed width, and while the heat dissipation substrate 1 is heated by means of a bonding device, the laser element is buried and adhered in the bonding agent by thermocompression bonding. In this case, the pressing force of the bonding device is properly adjusted and the laser element is prevented form being buried in the bonding agent 3 so far as a part, from which laser light is emitted, in the vicinity of the luminous junction region 4 of the semiconductor laser element 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for mounting a semiconductor laser element in a semiconductor laser device in which the semiconductor laser element is disposed on a heat dissipation base.

Generally, as shown in FIG. 1, in a semiconductor laser device, a semiconductor laser element 2 is bonded to an edge portion of a heat dissipation base 1 made of, for example, copper (Cu) with an adhesive 3 made of, for example, indium (un). In this case, in order to adhere the semiconductor laser element 2, the method is to apply a thin layer of adhesive 3 on the surface of the heat dissipation base 1, place the semiconductor laser element 2 on the adhesive 3, and fix the semiconductor laser element 2 by adhesive. In the semiconductor laser device formed by such a method, a part of the laser light from the semiconductor laser element 2 is reflected in an undesired direction on the surface of the adhesive 3 as shown by the solid arrow A'. The reason for this is that the distance between the light emitting junction region 4 of the semiconductor laser device 2 and the surface of the heat dissipation base 1 is extremely short, and the laser light is emitted with a certain spread in the vertical direction as shown by solid arrows A and B. The former is an unavoidable measure to improve heat dissipation, and the latter is based on the nature of semiconductor lasers, and both are unavoidable.Also, making the surface of the adhesive 3 optically flat is Since this is difficult, part of the laser light may be diffusely reflected on the surface of the adhesive 3 and may be scattered.

The present invention has been made in view of the above-mentioned points, and its purpose is to form an adhesive of a predetermined width on a heat dissipation base so that the central part of the cough width is convex, and to apply a semiconductor on the adhesive. An object of the present invention is to provide a method for assembling a semiconductor laser device in which a laser element is embedded by thermocompression bonding, thereby efficiently emitting laser light in a desired direction.

The purpose of this is to form a convex portion having a width slightly wider than the width of the semiconductor laser element in the laser beam emission direction on the upper surface of the heat radiation base in a semiconductor laser device in which a semiconductor laser element is disposed on a heat radiation base. Then, after melting a metal solder on the convex part to form an upwardly convex curved surface so that the surface is highest at the center of the width, and placing it so that the edge of the convex part is occupied by the metal solder. After solidifying, a part of the laser element is submerged in the solidified metal solder while heating the second base, and is thermocompression bonded with the laser element submerged so that the laser beam emitting part near the active layer of the laser element is exposed. This problem is solved by the method of the present invention.

Embodiments of the present invention will be described below with reference to the drawings.

The second part is a schematic sectional view of main parts for explaining the method of assembling a semiconductor laser device according to the present invention, and the same parts as in FIG. 1 are given the same reference numerals.

In the figure, reference numeral 1 denotes a heat dissipation base made of, for example, Cu, and a convex portion 5 having a width W slightly wider than the width P of the semiconductor laser element 2 and a height H is formed on the upper surface of the heat dissipation base 1. ing. For example, if the width of the semiconductor laser element 2 in the laser beam emission direction, that is, the width P in the directions A and B indicated by solid line arrows, is 0°311, then the width W3 of the convex portion 5 is 0.
．． It is set to 5 fins. Further, the height H of the convex portion 5 is, for example, 0.
．． It is about 3 ml.

The semiconductor laser element 2 is bonded to the upper surface of the convex portion 5 using an adhesive 3 made of, for example, In. It is formed by To do this, place an extra piece of Indium on top of the convex portion 5, which will become the adhesive 3! ! 2
When heated at WL, for example, about 160° C., the In piece melts over the entire upper surface of the convex portion, and the surface tension at that time is highest at the center, resulting in a predetermined curved shape.

In this way, applying the adhesive 3 in a curved shape such that the center part is highest is when the laser element 2 is embedded and mounted in the adhesive by thermocompression bonding as described later.
This is to prevent the emitted light from the laser element from being reflected on the adhesive surface.

Next, the semiconductor laser element 2 is placed on the adhesive 3 which has been raised to a predetermined width and solidified, and bonding 'A' is performed.
While heating the heat dissipation base 1 using the heat sink 1, the laser element is embedded and bonded into the adhesive by thermocompression bonding. In this case, it goes without saying that the pressure of the bonding device should be adjusted appropriately so that the part of the semiconductor laser element 20 near the light-emitting bonding region 4 from which the laser beam is emitted is not buried in the adhesive 3. It is important that the entire bottom surface of the element be in contact with the adhesive 3.

In this way, the light emitting junction region 4 of the semiconductor laser device 2
As shown by the solid arrows A and B, the laser light emitted from the laser beam spreads at an angle determined by the properties of the semiconductor laser element, and part of the laser light is not reflected from the adhesive surface as in the past, so it can be directed in a certain direction. There is no possibility that the intensity of the laser beam becomes stronger in a biased manner, and the emitted laser beam is also prevented from being diffusely reflected, making it possible to obtain a semiconductor laser device with high laser beam utilization efficiency. Furthermore, since the entire lower surface of the laser element is in contact with the In adhesive, the heat distribution in the width direction of the element is uniform, and deterioration of laser characteristics can be prevented.

By the way, when the width W of the convex portion 5 is formed to be 0.6 mm or more and the semiconductor laser element 2 is mounted on the surface of the adhesive 3.
This resulted in the inconvenience that a portion of the laser light from the laser beam was reflected in an undesired direction.

Note that if the purpose is simply to prevent unnecessary reflection from the adhesive, a convex having a width equivalent to the width in the laser beam emission direction of a semiconductor laser element as disclosed in Japanese Utility Model Application Publication No. 51-134377, for example. part is formed on the top of the heat dissipation base,
The laser element may be mounted on the upper surface of this convex portion, but in this case, as in the present invention, if the adhesive is raised upward in a convex shape and solidified, the laser element will be bonded by thermocompression. Both ends in the width direction are not in contact with the adhesive and are in a floating state, resulting in a temperature difference in the width direction of the element, which deteriorates the laser characteristics.

As is clear from the above description, the present invention basically involves forming a convex portion having a width slightly wider than the width of the semiconductor laser element in the laser beam emission direction on the upper surface of the heat dissipation base, and placing the semiconductor laser element on the convex portion. It is bonded by thermocompression using an adhesive, and has the advantage of being easy to assemble and realizing a high-performance semiconductor laser device in which no part of the laser beam is reflected on the surface of the adhesive.

A semiconductor laser device assembled using the method of the present invention,
For example, if used as a light source for a gas analyzer, a highly reliable gas analyzer in which the direction of laser light emitted from the light source is constant can be realized.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of main parts for explaining the structure of a conventional semiconductor laser device, and FIG. FIG. 1: Heat dissipation base, 2: Semiconductor laser element, 3: Adhesive, 4
: Light emitting junction area of the semiconductor laser element, 5: Convex portion formed on the top surface of the heat dissipation base, A, A"5B: Laser light, W: Width of the convex portion formed on the top surface of the heat dissipation base, P: Width of the convex portion formed on the top surface of the heat dissipation base. width.

Claims (1)

[Scope of Claims] A semiconductor laser device comprising a semiconductor laser element (2) disposed on a heat radiation base (1), wherein a width slightly larger than the width of the semiconductor laser element in the laser beam emission direction is provided on the upper surface of the heat radiation base. A convex portion (5) having a wide width is formed, and a metal solder (3) is melted on the convex portion to form an upwardly convex curved surface so that the surface is highest at the center, and the convex portion is curved upwardly. The laser element is placed so that it is occupied by the metal solder up to the edge and then solidified, and then, while heating the heat dissipation base, a part of the laser element is placed in the solidified metal solder, and the laser beam near the active layer of the laser element is placed. A method for assembling a semiconductor laser device, characterized by thermocompression bonding in a submerged state so that an emission portion is exposed.