JPH10200153A - Optical receiving/transmitting module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To bond a light receiving/emitting element easily onto a substrate while positioning accurately by filling a recess, made in any one of the substrate or the light receiving/emitting element, with solder and then bonding the light receiving/emitting element to the substrate while fitting the bonding faces tightly. SOLUTION: The light receiving/emitting module 10 comprises a semiconductor laser 12 bonded onto a silicon substrate 11 through solder H. The solder H fills a recess 13 made in the surface of the silicon substrate 11 through an air gap S and bonds the lower surface of the light receiving/emitting element 12 to the silicon substrate 11. The recess 13 has a plane area slightly larger than the area of the lower surface of the semiconductor laser 12. An optical fiber 14 is bonded through an adhesive into a V-groove 15 made in the silicon substrate 11 and protected by a retaining plate 16. Consequently, floating due to the solder layer is prevented and a constant relative positional relationship can be sustained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light receiving / transmitting optical module having a light receiving / emitting element such as a semiconductor laser fixed on a substrate, and more particularly, to a light receiving / light emitting element in which the light receiving / light emitting element is simply and accurately fixed to a substrate. / Transmission light module.

[0002]

2. Description of the Related Art One of the connections between a light receiving / emitting element such as a semiconductor laser and an optical waveguide, for example, an optical fiber, is shown in FIG.
There is a transmitting light module. In the receiving / transmitting optical module 60 shown in FIG. 6, 61 is a receiving / emitting element such as a semiconductor laser, and 62 is a substrate made of silicon or the like. The light receiving / light emitting element 61 and the substrate 62 are usually fixed with solder H. The optical fiber 63 is fitted in a V-shaped groove 65 provided in the substrate 62 and fixed by an adhesive or the like. The connecting portion between the light receiving / light emitting element and the optical waveguide in the light receiving / transmitting optical module having the above structure has a simple structure and is widely used. As a method for soldering the light receiving / light emitting element 61 and the substrate 62, there is a method shown in FIGS. FIG. 7A shows a thermocompression bonding method, and FIG. 7B shows a reflow method.

[0003] The thermocompression bonding method shown in FIG.
The solder H mounted between the substrate 1 and the substrate 62 is heated and melted by a heater 67 provided in the work base, and is simultaneously fixed by applying pressure to both. In the reflow method shown in FIG. 7B, the receiving / light emitting element 61 having the solder H previously mounted below the receiving / light emitting element 61 is positioned and fixed on the substrate 62, and is placed in a reflow furnace (not shown). Receiving / light emitting element 61
And the substrate 62 are fixed. 7A and 7B, the base metal surface of the substrate 62 and the
The lower solder bonding surface of the light emitting element 61 is a flat surface, and the melted and liquefied solder H permeates between the two to form a solder layer having a certain thickness.

[0004]

Here, it is required that the thickness of the solder layer is always constant due to the positional relationship with the optical fiber 63 to be connected. For this reason, usually, the amount of the solder H is kept constant, the thickness of the solder layer is kept constant, and the positional accuracy is maintained. The tolerance of the mounting position accuracy of the receiving / emitting element 61 and the optical fiber 63 in the receiving / transmitting optical module is determined by the tolerance of the optical axis deviation, and is desirably 1 μm or less in both the horizontal and vertical directions.

Considering the vertical direction, it is the sum of the accuracy of the position (depth) of the V-groove 65 for fixing the optical fiber 63 and the accuracy of the mounting position (height) of the light receiving / emitting element 61. The sub-micron level is required for the height accuracy target of the light emitting element 61. In the prior art, it was difficult to control the height of the light receiving / light emitting element 61 to submicron or less, for example, there was a variation in the thickness of the solder layer due to a variation in the amount of solder, and an inclination due to uneven solidification of the solder. .

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a receiving / transmitting optical module which can easily position and fix a receiving / light emitting element on a substrate with high accuracy.

[0007]

The present invention has the following means to solve the above problems.

The receiving / transmitting optical module according to claim 1 of the present invention is a receiving / transmitting optical module having a receiving / emitting element fixed on a substrate by soldering, wherein the solder is the substrate or the receiving / emitting element. And the bonding surfaces of the substrate and the light receiving / light emitting element are tightly fixed to each other by being filled in a recess provided in at least one of the above.

According to a second aspect of the present invention, there is provided a receiving / transmitting optical module, wherein the solder filled in the recess is filled with a void in the recess.

According to the receiving / transmitting light module of the first aspect of the present invention, the bonding surface of the substrate and the receiving / light emitting element are brought into close contact with each other by the solder filled in the recess provided in at least one of them. As a result, the solder layer does not float and the positional relationship between the two can be always kept constant. For example, even if the amount of solder filled in the depression exceeds the volume of the depression, both are pressed to bring the joining surfaces of both into close contact, and the solder between the joining surfaces is out of the joining surface. By extruding, the floating due to the solder layer is eliminated, and the positional relationship between the two can be easily kept constant. Since the area of the joint surface between the two is reduced by the depression, the solder between the joint surfaces can be easily pushed out of the joint surface.

According to the receiving / transmitting optical module of the second aspect of the present invention, since the solder is filled with a void within a range not to exceed the volume of the recess, the solder in the recess is connected to the substrate / receiver. It does not leak to the bonding surface of the light emitting element. Therefore, there is no floating due to the solder layer, and the two are always closely contacted and fixed, so that the positional relationship between the two can always be kept constant. Since the solder may be set within a range not exceeding the volume of the depression, the management of the solder filling amount is facilitated, and the productivity of the receiving / transmitting optical module is improved.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a receiving / transmitting optical module according to the present invention will be described below in detail with reference to FIGS. (Embodiment 1) A receiving / transmitting optical module 10 shown in FIG.
The semiconductor laser 12 is fixed on a silicon substrate 11 by solder H. Solder H is silicon substrate 11
The cavity 13 provided on the surface is filled with a gap S to fix the lower surface of the light receiving / emitting element 12 to the silicon substrate 11. The plane area of the depression 13 is slightly smaller than the area of the lower surface of the semiconductor laser 12. In FIG. 1, reference numeral 14 denotes an optical fiber,
4 is mounted in a V-groove 15 formed in the silicon substrate 11, fixed with an adhesive, and fixed and protected by a holding plate 16.

FIGS. 2 and 3 show one embodiment of a method for manufacturing the above-mentioned receiving / transmitting optical module 10. FIG. Silicon substrate 1
A dent 13 having a predetermined depth is formed at a predetermined position of the substrate 1 by directional etching. The size of the recess 13 is slightly smaller than the size of the area of the lower surface of the semiconductor laser 12 mounted on the silicon substrate 11. A solder bump H0 made of AuSn is formed at the bottom of the depression 13. The solder bumps H0 can be formed by reflowing the solder chips. The height of the solder bump H0 is made higher than the depth of the depression 13 as shown in FIG. 3, but the amount of the solder bump H0 is made smaller than the volume of the depression 13 so that when the solder bump H0 is melted, the depression 13
Make the amount less overflowing. The solder bump H0 is placed in a state of being formed in the depression 13 of the silicon substrate 11. The horizontal position accuracy of the semiconductor laser 12 can be controlled within 1 μm by using the depression 13 as a mark.

In the above state, both are heat-pressed. The solder bump H0 is softened and melted by heating and pressure bonding to form a depression 13
And the lower surface of the semiconductor laser 12 is
1 and comes into close contact with the upper surface of the substrate. When the heating is completed in a state where both are in close contact with each other, the solder H starts to solidify. Here, when the solder H is condensed, the solder H thermally contracts and a force pulling the semiconductor laser 12 downward acts, so that the semiconductor laser 12 is securely adhered and adhered without being lifted from the silicon substrate 11. Then, the optical fiber 14 is connected to the V-groove 1
5, the receiving / transmitting light module 10 is manufactured by filling the inside with the adhesive and fixing it with the holding plate 16.

(Embodiment 2) FIGS. 4 and 5 (a),
(B) is a receiving / transmitting optical module 2 showing another embodiment.
0 is a perspective view showing a part of a manufacturing process of No. 0. FIG. The receiving / transmitting optical module 20 shown in FIG. 4 has a transmitting side composed of a semiconductor laser 22 and a SiO ₂ waveguide 23 on a silicon substrate 21 and a receiving side composed of an SiO ₂ waveguide 24 and an end face incident type photodiode 25. The sides are integrally formed. Solder blocks H1 and H2 are formed at the four corners of the joint surface on the lower surface of the semiconductor laser 22 and the photodiode 25. In the present embodiment, the depression 26 of the silicon substrate 21 not only functions as a solder pool,
As shown in FIGS. 5 (a) and 5 (b), the solder blocks H1, H
2 and serves as a positioning hole for the silicon substrate 21, the semiconductor laser 22, and the photodiode 25.

The solder blocks H 1 and H 2 correspond to the semiconductor laser 2.
In the wafer process of the photodiode 2 and the photodiode 25, etching is performed by photolithography after AuSn evaporation or sputter deposition, so that the positional accuracy can be sufficiently reduced to 1 μm or less. The solder block H
1, the height of H2 is higher than the depth of the depression 26, as in the first embodiment. Hereinafter, since both are bonded by heating and pressure bonding in the same manner as in the first embodiment, detailed description will be omitted. Also, in the present embodiment, the solder H
6 is filled and fixed with a void S in the same manner as in the first embodiment.

In each of the above embodiments, an example has been described in which the depression serving as a solder pool is provided on the substrate side. However, the depression may be provided on the light receiving / light emitting element side, or both may be provided. It may be provided. Also, it is desirable that the solder filled in the dent does not exceed the volume of the dent,
For example, even if the capacity is exceeded, the area of the joint surface between the two is reduced by the depression, so that the solder between the joint surfaces can be easily pushed out of the joint surface. It becomes possible to adhere and fix.

[0018]

As described above, according to the receiving / transmitting light module according to the first aspect of the present invention, the substrate and the receiving / light emitting element are filled in at least one of the recesses provided in the solder. As a result, the bonding surfaces of the two are closely adhered and fixed, so that the floating due to the solder layer is eliminated and the positional relationship between the two can always be kept constant. For example, even if the amount of solder filled in the depression exceeds the volume of the depression, the area of the joint surface between the two is reduced by the depression, so the solder between the joint surfaces can be easily removed. It can be extruded out of the joining surface, and the joining surface of both can be kept in a close contact state, and the positional relationship between them can be easily kept constant.

According to the receiving / transmitting optical module of the second aspect of the present invention, since the solder is filled with a void within a range not exceeding the volume of the recess, the solder in the recess is connected to the substrate. It does not leak to the bonding surface of the light emitting element. Therefore, there is no floating due to the solder layer, and the two are always closely contacted and fixed, so that the positional relationship between the two can always be kept constant. Since the solder may be set within a range not exceeding the volume of the depression, the management of the solder filling amount is facilitated, and the productivity of the receiving / transmitting optical module is improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a receiving / transmitting optical module of the present invention.

FIG. 2 is a perspective view showing a part of a manufacturing process of the receiving / transmitting optical module of FIG.

FIG. 3 is a sectional view showing another part of the manufacturing process of the receiving / transmitting optical module of FIG. 1;

FIG. 4 is a perspective view showing a part of a manufacturing process of another embodiment of the receiving / transmitting optical module of the present invention.

5A and 5B are cross-sectional views illustrating another part of the manufacturing process of the receiving / transmitting optical module of FIG.

FIG. 6 is a side view showing a part of a conventional method for manufacturing a receiving / transmitting optical module.

FIGS. 7A and 7B are explanatory views showing a conventional method for manufacturing a receiving / transmitting optical module.

[Explanation of symbols]

 Reference Signs List 10 receiving / transmitting optical module 11 silicon substrate 12 semiconductor laser 13 depression 14 optical fiber 15 V groove 16 holding plate H solder S void

Claims (2)

[Claims] 1. A receiving / transmitting light module having a receiving / emitting element fixed on a substrate by solder, wherein the solder is filled in a recess provided in at least one of the substrate and the receiving / emitting element. A receiving / transmitting light module, wherein the respective bonding surfaces of the substrate and the receiving / light-emitting element are closely adhered and fixed. 2. The receiving / transmitting light module according to claim 1, wherein the solder filled in the recess is filled with a void in the recess.