JPH01158406A - Manufacture of optical semiconductor assembly - Google Patents

Abstract

PURPOSE:To obtain high optical coupling efficiency stably for a long period by interposing an annular solder layer between a flange and a mount base, and projecting laser light and fusing the solder layer. CONSTITUTION:The annular solder layer 5 is interposed between the flange 2 and mount base 4 and the laser light is projected along the flange 2 to fuse the solder layer 5. Thus, the laser light is projected along the flange of a lens holder, e.g. as shown by an arrow to fuse the solder layer, so a solder zone is heated uniformly. Residual heat stress is prevented from being generated at the part. Consequently, a creep is prevented from being generated in solidified solder and the optical coupling efficiency is prevented from varying with time.

Description

[Detailed Description of the Invention] ``-1 To obtain stable and high optical coupling efficiency over a long period of time with respect to a method for manufacturing an optical semiconductor assembly that is a component of an optical semiconductor module used in the field of optical communication or optical transmission. A method for manufacturing an optical semiconductor assembly comprising soldering a ring-shaped flange of a lens holder and a mounting table for an optical semiconductor chip, the method comprising: interposing a ring-shaped solder layer between the flange and the mounting table; The solder layer is melted by irradiating laser light along the flange.

The present invention relates to a method for manufacturing an optical semiconductor assembly, which is a component of an optical semiconductor module used in the field of optical communication or optical transmission.

For example, in an optical communication system that uses an optical fiber as an optical transmission line, in order to introduce the emitted light from an optical semiconductor element such as a semiconductor laser (LD) or a light emitting diode (LED) into the optical fiber, the optical semiconductor element and the optical An optical semiconductor module is used in which a fiber input end face is fixed in a predetermined positional relationship and a condensing lens is provided between them. In this type of optical semiconductor module, since the positional relationship between the components directly affects the optical coupling efficiency, each component is required to be positioned with extremely high precision of 1 μm or less. Furthermore, it is required that this positioning accuracy be maintained for a long period of time.

Figure 8 is a cross-sectional configuration diagram of a conventional general optical semiconductor module. An optical semiconductor assembly 53 including a lens 51 and an optical semiconductor cord 52, a ferrule 56 into which an optical fiber 55 is inserted and fixed, and a lens 54 are connected to a cylindrical member 57.
An optical fiber assembly 59 inserted into and fixed to the optical fiber assembly 59 is placed opposite to the optical fiber assembly 59 with a case 58 interposed therebetween. With this structure, the optical semiconductor element 52, the lenses 51, 54, and the end faces of the optical fiber 55 can be positioned in a predetermined positional relationship.

FIG. 9 is an explanatory diagram of a conventional method of manufacturing the above-mentioned optical semiconductor/body assembly. Lens holder 6 to which lens 51 is fixed
1 and a mounting table 62 to which the optical semiconductor element 52° is fixed are brought into close contact with each other through a solder layer (not shown), and this contact portion is heated by conduction using a high-frequency heating work coil 63 to perform contactless soldering. It is something.

Problems to be Solved by the Invention In the conventional method shown in FIG. 9, the optical axis is adjusted by adjusting the position of the lens holder 61 with respect to the mounting table 62, so that the optical coupling efficiency is maximized. Is possible. However, since the distance between the lens 51 and the optical semiconductor element 52 is extremely small (for example, 25 μm), even a slight positional shift in the lens holder 61 over time after fixation causes a problem in that the optical coupling efficiency decreases. Ta.

The present invention was created in view of these problems.
The aim is to obtain stable and high optical coupling efficiency over a long period of time.

Means for Solving the Problem When the above-mentioned fluctuation in optical coupling efficiency over time was investigated, it was found that the cause was creep occurring in the soldering part. In other words, in the conventional method, the heating temperature varies within the soldering part due to the non-uniformity of the shape of the work coil for high frequency heating, and as a result, the residual thermal stress generated when the solder solidified part is cooled causes creep, causing optical This resulted in a decrease in coupling efficiency. Therefore, in order to prevent the occurrence of creep, it is effective to heat the soldering parts evenly.

FIG. 1 is a diagram showing the principle of the present invention. The method for manufacturing an optical semiconductor assembly of the present invention is a method for manufacturing an optical semiconductor assembly in which an annular flange 2 of a lens holder 1 and a mounting base 4 for an optical semiconductor depth 3 are soldered together. An annular solder 15 is interposed between the mounting bases 4,
The solder layer 5 is configured to be irradiated with a laser beam along the flange 2 to melt the solder layer 5.

1-11 In the method of the present invention, the solder layer is melted by irradiating the laser beam along the flange of the lens holder, for example in the direction indicated by the arrow in FIG. The parts are heated evenly, thus preventing the generation of residual thermal stresses in the parts. As a result, creep is prevented from occurring in the solidified solder, and there is no fear that the optical coupling efficiency will change over time.

Friend-Ll Embodiments of the present invention will be described below based on the drawings.

FIG. 2 is a perspective view of a mounting table on which an optical semiconductor chip is fixed. An LD chip 11 is fixed on a mounting table 13 via a support member 12 for heat radiation and a ground electrode. As for the material of the mounting table 13, a metal material with a small coefficient of thermal expansion, such as Kovar plated with Ni or Au, can be used to ensure good soldering properties.

FIG. 3 is a cross-sectional view of a lens holder that can be used to implement the present invention. A spherical lens 24 is fixed to a generally cylindrical lens holder 22 having an annular flange 21 by, for example, being press-fitted into a hole 23 for extracting emitted light.

FIG. 4 is a cross-sectional view of a fiber guide that can be used to implement the present invention, FIG. 5 is a cross-sectional view taken along line v-v in the figure, and FIG. 6 is a cross-sectional view taken along line VI-VI. It is. A plurality of optical fibers 32 are bundled, this is covered with a stretchable and flexible covering material 31, and a generally conical molding member 33 is inserted from one end side to change the cross-sectional shape of the optical fiber bundle at the end side. is annular. According to such a configuration of the fiber guide 30, the guided light travels along each optical fiber 32, so that the output light beam can be annular.

FIG. 7 is an explanatory diagram of a soldering process showing an embodiment of the present invention. In this embodiment, the mounting table 13 and the lens holder 22
and solder 41 are brought into close contact with each other via the annular solder 41, and in this state, the optical axis is adjusted. Laser light is irradiated along the flange 21 of the lens holder or the annular thin film solder 41 to perform soldering. That's what I do. Irradiation of laser light onto such an annular region can be accomplished by using, for example, a YAG laser 42 as a laser light source, and emitting light from the YAG laser 42 as shown in FIGS.
This is possible by condensing and irradiating light into a narrow annular pattern through the fiber guide 30 and convex lens 43 shown in the figure. Generally, if the optical power distribution within the fiber cross section in Fig. 5 is uniform, the optical power distribution within the fiber cross section in Fig. 6 will also be uniform. It is heated evenly.

In this embodiment, Pb-8n is used as the annular thin film solder 41.
When eutectic solder (melting point 183°C) was used and laser beam irradiation was performed for 6 seconds with the output of the YAG laser 42 set to 80 W, no temporal variation was observed in the melting and solidification of the solder in the circumferential direction. . Furthermore, using the obtained optical semiconductor assembly, for example, a module such as the one shown in FIG.
When a thermal cycle test (total of 200 cycles) from .degree. C. to +60.degree. C. was conducted, the decrease in optical coupling efficiency was within 0.2 dB for all 10 samples.

Considering that with conventional methods, it was often seen that the optical coupling efficiency changed by more than 0.2 dB under the same test conditions.
The significance of the method of the invention is clear.

Effects of the Invention As detailed above, according to the present invention, since the soldering part is evenly heated by the laser beam, the deviation of the optical axis due to the creep phenomenon after solder solidification is prevented. As a result, it is possible to provide an optical semiconductor assembly that is stable for a long period of time and has high optical coupling efficiency.

[Brief Description of the Drawings] Fig. 1 is a diagram showing the principle of the present invention, Fig. 2 is a diagram showing an embodiment of the present invention, and is a perspective view of a mounting table on which an LD chip is fixed. 4 is a sectional view of a fiber guide that can be used to implement the present invention; FIG. 5 is a sectional view taken along the v-v line in FIG. 4; The figure is a sectional view taken along the VI-VI line in Fig. 4, Fig. 7 is an explanatory diagram of the soldering process showing an embodiment of the present invention, and Fig. 8 is a sectional view of a conventional general optical semiconductor module. FIG. 9 is an explanatory diagram of a conventional manufacturing method of an optical semiconductor assembly. 1.22... Lens holder, 2.21... Flange, 3... Optical semiconductor chip, 4.13... Mounting table, 5... Solder layer, 11... LD chip, 24. ...Lens, 30...Fiber guide, 32...Optical fiber, 41...Annular thin film solder, 42...YAG laser. Yan Yu Ming's source ring concave Fig. 1 (a) 6q Fig. 2 22: Lens ° holder now C1E1. Jhi, if 1J β mouth
Li (1st column, 1st line, Figure 5, Figure 6)
Arrogant e-11, h row B] Figure 7

Claims (1)

[Claims] (1) In a method of manufacturing an optical semiconductor assembly in which an annular flange (2) of a lens holder (1) and a mounting table (4) for an optical semiconductor chip (3) are soldered together. , an annular solder layer (5) is interposed between the flange (2) and the mounting table (4), and a laser beam is irradiated along the flange (2) to melt the solder layer (5). A method for manufacturing an optical semiconductor assembly, characterized in that: (2) The irradiation of the laser beam is performed through a fiber guide (30) formed by arranging the output ends of optical fibers (32) in a circular cross-section. A method for manufacturing an optical semiconductor assembly according to section 1.