JPH06140644A - Manufacture of optical semiconductor module - Google Patents

Abstract

PURPOSE:To inexpensively obtain an optical semiconductor module by fitting a stem into a holder with a positioning ring interposed between the outer periphery of the stem and the holder, and by bringing the upper surface of the stem into contact with a bottom surface of a stepped hole of the holder with a projection ring sandwiched between them, thereby preventing the destruction of airtightness due to excessive heat stress. CONSTITUTION:After a projection ring 11 and a positioning ring 8 have been inserted into grooves made on a holder 1, the outer periphery of the upper surface of a stem 2 is brought into contact with the bottom surface of a stepped hole of the holder 1 with the projection ring 11 interposed between them at the same time that the stem 2 is fitted into the hole of the holder 1 with the positioning ring 8 sandwiched between them. In this state, the projection ring 11 is fused by resistance welding under pressure, so that the holder 1 is fixed to the stem 2. This makes it possible to reduce the area of a contact where the holder 1 is soldered to the stem 2; to prevent an increase in the amount of current at the time of resistance welding; and to prevent the destruction of airtightness due to stress that is exerted on the stem 2 at the time of welding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical semiconductor module.

[0002]

2. Description of the Related Art An optical semiconductor chip is usually used by being optically coupled with an optical fiber when used for optical fiber communication. However, in order to simplify such optical coupling, an optical semiconductor chip is used. It is customary to use as an optical semiconductor module in which a lens and an optical fiber are fixed and integrated at a position where optical coupling is optimum.

FIG. 3 is a sectional view of an example of a conventional optical semiconductor module.

As shown in FIG. 3, in a conventional optical semiconductor module, an optical semiconductor chip 4, a holder 1, a rod lens 6, a stem 2 having the optical semiconductor chip 4 mounted thereon, and an optical semiconductor chip 4 are hermetically sealed. It was composed of a cap 5 attached to the stem 2 so as to stop, a ferrule 3a attached to the optical fiber core wire 3b, and a slide ring 7.

The holder 1 fixes the stem 2 to which the optical semiconductor chip 4 is attached and the rod lens 6, and also the ferrule 3 attached to the optical fiber core wire 3b.
It serves to fix a through the slide ring 7. In the optical semiconductor module, the optical fiber 3b, the rod lens 6, and the optical semiconductor chip 4 need to be fixed after adjusting their positions so as to obtain optimum optical coupling efficiency, and the slide ring 7 is fixed to these ferrules 3a. And the holder 1 are fixed in a free positional relationship. The ferrule 3a is movable with respect to the slide ring 7 in the optical axis direction, and the slide ring 7 is fixed with respect to the holder 1 with respect to the optical axis. It is movable in the vertical direction. After the ferrule 3a is adjusted to the position where the optical coupling is optimum,
The ferrule 3a and the slide ring 7 and the slide ring 7 and the holder 1 are fixed to the holder 1 via the slide ring 7 by, for example, YAG laser welding.

The rod lens 6 is fixed to the holder 1 in advance by soldering, resin or press-fitting. As a method of fixing the stem 2 to the holder 1, there are solder fixing, resin fixing, welding fixing, etc., but recently, 85 ° C. Reliability in a high temperature environment is required, and from such a background, fixing by a welding method such as YAG laser welding or resistance welding is becoming mainstream in order to obtain more stable optical coupling.

[0007]

In the conventional optical semiconductor module described above, when the stem 2 and the holder 1 are fixed, the optical fiber core wire 3b, the rod lens 6, and the optical semiconductor chip 4 are aligned on the same optical axis. Since it is necessary to adjust the position of the stem 2, the stem 2 is fixed to the holder 1 to which the rod lens 6 is attached with high positional accuracy. Therefore, the holder 1 is provided with a stepped hole that fits into the outer diameter of the stem 2 through a very small gap of about several tens of microns.
Position adjustment is performed with the processing dimensional accuracy of the member. In order to obtain high reliability in such an optical semiconductor module, the YAG laser welding method and the resistance welding method are mentioned as the fixing method of the stem 2 and the holder 1 as described above.

In the YAG laser welding direction, if the gap between the stem 2 and the holder 1 is too large (50 microns or more), welding becomes difficult. Therefore, the stepped hole for fitting provided in the holder 1 and the outside of the stem 2 are provided. It is necessary to increase the dimensional accuracy of the diameter to several tens of microns, and there is the disadvantage that the required equipment and work man-hours are relatively high compared to the resistance welding method.

On the other hand, the resistance welding method is used for welding 2
The two parts are brought into contact with each other to flow an electric current, and the heat generated by the resistance of the contact part is used to apply pressure to perform welding. As shown in FIG. 4, in the conventional structure, as shown in FIG. In addition, the stem side surface 9b comes into contact with the holder 1, and an electric current also flows through this portion. Since the contact area as a whole becomes large in this way, the amount of electric current required for welding also becomes large, so that the amount of heat generated during welding also becomes large and, as a result, excess heat is applied to the stem 2 compared to the optimum welding conditions. This has the drawback that stress is applied and the airtightness of the stem 2 may be broken. In addition, in order to solve these problems, FIG.
As shown in FIG.
There is a case where the contact area is provided to reduce the contact area, but even in this case, since the current still flows on the stem side surface 9b, the effect is halved. In addition, it is difficult in terms of accuracy to provide the projection ring 11 having a convex shape in a small area when the holder 1 is processed, and the processing cost increases.

An object of the present invention is to provide a method of manufacturing an optical semiconductor module which can be obtained at a low cost without causing airtight destruction due to excessive heat stress.

[0011]

According to the present invention, there is provided an optical semiconductor chip, a stem on which the optical semiconductor chip is mounted, a cap sealed to the stem for hermetically sealing the optical semiconductor chip, and fixed to the stem. A holder and an optical fiber fixed to the holder, the method comprising the step of fixing the holder to the stem by resistance welding, wherein the inner surface of the holder and the outer periphery of the stem are provided. The side surface is fitted via a positioning ring, and the holder and the stem outer peripheral portion are brought into contact with each other via a projection ring, and the projection ring is melted by resistance welding to fix the holder to the stem. Including the step of

[0012]

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

1A and 1B are a sectional view of a first embodiment of the present invention and a partially enlarged sectional view of a welded portion before welding.

In the first embodiment, as shown in FIGS. 1A and 1B, an optical semiconductor chip 4, a holder 1 and a holder 1 are provided.
A rod lens 6 supported at the center of the optical axis, a stem 2 on which an optical semiconductor chip 4 is mounted, a cap 5 attached to the stem 2 so as to hermetically seal the optical semiconductor chip 4, and an optical fiber core wire 3b. The ferrule 3a
A slide ring 7 supporting the ferrule 3a, a positioning ring 8 arranged between the side surface of the stem 2 and the side surface of the stepped hole of the holder 1, and a positioning ring 8 arranged between the upper surface of the stem 2 and the bottom surface of the stepped hole of the holder 1. It is composed of a projection ring (conductive) 11.

Here, the holder 1 is provided with grooves for fixing the projection ring 11 and the positioning ring 8 on the bottom surface and side surface of the stepped hole into which the stem 2 is inserted, and the projection ring 11 and the positioning ring are provided in these grooves. After inserting 8, the stem 2 is fitted into the hole of the holder 1 via the ring-shaped positioning ring 8 and at the same time, the outer periphery of the upper surface of the stem 1 is projected onto the projection ring 11
The bottom surface of the stepped hole of the holder 1 is brought into contact with the holder 1, and the projection ring 11 is melted by pressure welding to fix the holder 1 to the stem 2. The projection ring 11 is conductive and usually has a diameter of 100-300 μm.
In this example, a stainless steel wire of SUS304 was put in the groove of the holder 1 to perform the test. The positioning ring 8 is set so as to have a gap with a diameter of about ten and several microns or less with respect to the outer diameter of the stem 2 and the inner diameter of the stepped hole of the holder 1 for fitting. It serves to mechanically determine the fixed position of the stem 2 and to reduce the contact current between the side surface of the stem 2 and the holder 1 during resistance welding of the fixed position of the holder 1 and the stem 2. In this example, a stainless steel wire of SUS304 having a high wire diameter accuracy was inserted into the groove in the same manner as the projection ring 11 in terms of fitting accuracy.

2 (a) and 2 (b) are a sectional view of a second embodiment of the present invention and a partially enlarged sectional view of a welded portion before welding.

The difference between the second embodiment and the first embodiment is that
As shown in FIGS. 2A and 2B, the spherical lens 12 is attached to the cap 5 instead of the rod lens attached to the holder, and the positioning ring 8 is an insulator. As described above, when the lens 12 is not fixed to the holder 1 but the optimum position adjustment of the optical coupling is performed between the optical fiber core wire 3b and the stem 2, the mounting position of the stem 2 to the holder 1 is determined. Accuracy can be controlled on the order of hundreds of microns,
Since the positioning ring is not required to have dimensional accuracy as in the case of the above embodiment, the positioning ring 8 may be a plastic material such as nylon.

Therefore, compared to the first embodiment, in the second embodiment, the dimensional accuracy of the inner diameter of the fitting hole of the holder 1 and the outer diameter of the stem 2 can be loosened, and the positioning ring 8 is also inexpensive. Is applicable, the optical module can be constructed at a lower cost.

[0019]

As described above, in the optical semiconductor module of the present invention, the holder and the outer diameter of the stem are fitted through the positioning ring, and the bottom surface of the stepped hole of the holder and the upper surface of the stem are arranged. By making contact with the projection ring, it is possible to reduce the area of the contact portion to be welded by resistance welding fixing of the holder and the stem, prevent the amount of current during welding from increasing, and suppress excessive heat generation. Thus, there is an effect that airtight destruction due to stress on the stem during welding can be suppressed and an inexpensive optical semiconductor module can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment of the present invention and a partially enlarged sectional view of a welded portion before welding.

FIG. 2 is a sectional view of a second embodiment of the present invention and a partially enlarged sectional view of a welded portion before welding.

FIG. 3 is a sectional view of an example of a conventional optical semiconductor module.

FIG. 4 is a partially enlarged cross-sectional view of a welded portion for explaining an example of a conventional method for welding an optical semiconductor module.

FIG. 5 is a partial enlarged cross-sectional view of a welded portion for explaining another example of the conventional method for welding an optical semiconductor module.

[Explanation of symbols]

 1 Holder 2 Stem 3a Ferrule 3b Optical Fiber Core 4 Optical Semiconductor Chip 5 Cap 6 Rod Lens 7 Slide Ring 8 Positioning Ring 9a Originally Welding Contact 9b Stem Side Side 11 Projection Ring 12 Spherical Lens

Claims (1)

[Claims] 1. An optical semiconductor chip, a stem on which the optical semiconductor chip is mounted, a cap sealed to the stem to hermetically seal the optical semiconductor chip, a holder fixed to the stem, and the holder. An optical fiber to be fixed, in the method for manufacturing an optical semiconductor module having a step of fixing the holder to the stem by resistance welding,
The inner surface of the holder and the outer peripheral side surface of the stem are fitted via a positioning ring, and the holder and the stem upper surface outer peripheral portion are brought into contact with each other via a projection ring, and the projection ring is melted by resistance welding. And a step of fixing the holder to the stem, the method for manufacturing an optical semiconductor module.