JP2007322815A - Optical semiconductor module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an optical semiconductor module having stable characteristics such that positional deviation at the tip end of an optical fiber is small relative to an optical semiconductor element and that a change in optical coupling efficiency is small between the optical fiber and the optical semiconductor element, in the occurrence of thermal deformation of a light shielding resin which covers the outside of transparent resin sealing the optical fiber tip end and the optical semiconductor element. <P>SOLUTION: The optical semiconductor module includes: an engaging part in which an optical fiber 1 and a photodetector 2 of the optical semiconductor element are engaged with each other by a first resin 3; a surrounding part which surrounds the engaging part with a side face opposing the engaging part across the photodetector 2 and with a pair of faces nearly vertical to that side face and opposing to each other; and a second resin 8 which is filled in the surrounding part, wherein the photodetector 2 is attached to the surrounding part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical semiconductor module used for transmission / reception of an optical signal using an optical waveguide such as an optical fiber.

  In a conventional optical semiconductor module, an optical fiber and a light receiving element, which is an optical semiconductor element disposed opposite to the optical fiber tip, are optically coupled, and the optical fiber tip and the optical semiconductor element are transparent together. It was sealed with resin, and the outside of the transparent resin was sealed with a light-shielding resin with low moisture permeability. In addition, the light receiving element is mounted on an element mounting portion cut and raised on the lead frame (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 10-084122 (page 2-3, FIG. 1)

  In the conventional optical semiconductor module, the light-shielding resin that seals the optical fiber and the optical semiconductor element expands or contracts in accordance with changes in the ambient temperature. Since the position of the optical fiber is displaced by the expansion or contraction of the resin, the position of the tip of the optical fiber facing the optical semiconductor element is also displaced. Further, since the light shielding resin is not formed symmetrically with respect to the optical axis of the optical semiconductor element and the optical fiber, the positional deviation of the optical fiber tip with respect to the optical semiconductor element greatly affects the expansion or contraction of the resin. Easy to receive. For this reason, there has been a problem that the relative position between the semiconductor element and the optical fiber tip is shifted due to a change in the ambient temperature, and the optical coupling efficiency between the optical semiconductor element and the optical fiber changes.

  The present invention has been made to solve the above-described problems, and even if the light shielding resin covering the outside of the transparent resin sealing the optical fiber tip and the optical semiconductor element is thermally deformed, the optical fiber tip. An optical semiconductor module is obtained in which the positional deviation of the optical fiber tip at the optical coupling portion between the optical fiber and the optical semiconductor element is small, the optical coupling efficiency between the optical fiber and the optical semiconductor element is small, and the characteristics are stable even when the temperature changes. Is.

  An optical semiconductor module according to the present invention includes an optical fiber, an optical semiconductor element optically coupled to the optical fiber, an engagement portion in which the optical fiber and the optical semiconductor element are engaged by a first resin, An enclosing portion that surrounds the engaging portion by a side surface facing the engaging portion with the semiconductor element interposed therebetween and a pair of surfaces that are substantially perpendicular to the side surface and face each other, and a second resin filled in the enclosing portion The optical semiconductor element is mounted on the enclosure.

  An optical semiconductor module according to the present invention includes: an enclosing portion that surrounds the engaging portion with a side surface facing the engaging portion across the optical semiconductor element and a pair of surfaces that are substantially perpendicular to the side surfaces and face each other; Even if the resin covering the optical fiber tip and the outside of the transparent resin sealing the optical semiconductor element is thermally deformed due to a change in ambient temperature, the light with respect to the optical semiconductor element is By reducing the positional deviation of the fiber tip, the change in optical coupling efficiency between the optical fiber and the optical semiconductor element with respect to the temperature change is small, and stable characteristics can be obtained.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram of an optical semiconductor module according to Embodiment 1 for carrying out the present invention. 2 is a cross-sectional view of the optical semiconductor module shown in FIG. The second resin is not shown in FIG. 1 and 2, an optical fiber 1 that is an optical waveguide is optically coupled to a light receiving element 2 that is an optical semiconductor element. The optical fiber 1 and the light receiving element 2 are engaged by a first resin 3 that is a transparent resin. A portion engaged by the first resin 3 is an engaging portion. In the present embodiment, the light receiving element 2 is a photodiode.

  As shown in FIGS. 1 and 2, a resin frame 4 that is a frame constituting the outer shape of the optical semiconductor module is provided, and a lead frame 5 and leads 6 and 7 are supported on the resin frame 4. In FIG. 1, the eaves surface 5c of the lead frame 5 shows only the outer shape. The light receiving element 2 is mounted on a lead frame 5 which is a metal member. The resin frame 4 has a structure including a side frame and a bottom plate, and is formed by bonding and fixing the bottom plate to the side frame. Even if the resin before curing is poured into the frame of the resin frame 4, the resin frame 4 has a box-like structure so that the resin does not flow out of the module. The resin frame 4 may be integrally formed. The method for forming the resin frame 4 may be potting using a dam agent or transfer molding. A region surrounded by the resin frame 4 is filled with the second resin 8. A part of the optical fiber 1, the light receiving element 2, the first resin 3, and the lead frame 5 are covered with the second resin 8.

  FIG. 3 is a perspective view of the lead frame in the first embodiment. A part of the flat portion of the lead frame 5 which is a metal member is cut and raised by approximately 90 degrees, and further, the front end side of the cut and raised portion is bent to form a surrounding portion. The encircling portion is a bottom surface 5a that is a part of the flat portion of the lead frame 5 that is not cut and raised, and an eaves that is formed to be parallel to the bottom surface 5a on the tip side of the cut and raised portion of the lead frame 5 It is constituted by a surface 5c and a side surface 5b which is the bottom surface 5a side of the cut and raised portion of the lead frame 5, and surrounds the engaging portion. The side surface 5 b faces the engaging portion between the optical fiber 1 and the light receiving element 2 with the light receiving element 2 interposed therebetween. The bottom surface 5a and the eaves surface 5c are a pair of surfaces, and are substantially perpendicular to the side surface 5b and face each other. In addition, the light receiving element 2 is attached to the side surface 5b constituting the enclosure.

  Next, the manufacturing method of an enclosure part is demonstrated. The enclosing portion is formed by the lead frame 5. The light receiving element 2 is die-bonded and wire-bonded to the lead frame 5 before cutting. Then, a part of the flat portion of the lead frame 5 to which the light receiving element 2 is die-bonded is cut and raised by approximately 90 degrees to form a bent portion. The bent portion is cut and raised from a location far from the region where the optical fiber 1 is mounted. Furthermore, the eaves surface 5c parallel to the bottom surface 5a is formed by bending the front end side of the bent portion. That is, the eaves surface 5c is a surface formed so as to be parallel to the bottom surface 5a on the tip side of the portion where the lead frame 5 which is a metal member is cut and raised. The side surface 5b is a surface on the bottom surface 5a side where the lead frame 5 is cut and raised. As shown in FIG. 1, when viewed from the top of the optical semiconductor module (the open side of the resin frame 4), the eaves surface 5 c has a width that covers at least the engaging portion between the optical fiber 1 and the light receiving element 2 and the light receiving element 2. Have. As a result, the engaging portion between the optical fiber 1 and the light receiving element 2 is sandwiched by the same lead frame member from above and below.

  The optical fiber 1 is aligned so that the optical coupling efficiency with the light receiving element 2 is maximized. After completion of alignment, the tip end portion of the optical fiber 1 and the light receiving element 2 are fixed by the first resin 3 as shown in FIG. As the first resin 3, a resin that is transparent to light incident via the optical fiber 1 is used. As the first resin 3, for example, a transparent silicone resin or a transparent epoxy resin can be applied.

  After fixing the tip of the optical fiber 1 with the first resin 3, at least the tip of the optical fiber 1 and the light receiving element 2 are used to protect the wires and other components wired by wire bonding from foreign matters. The second resin 8 is poured so as to be buried and cured. In addition, when a UV curable type is used for the first resin 3, the second resin 8 can be injected and cured after the tip portion of the optical fiber 1 is fixed with the first resin 3 by UV light. Compared to the case of using a thermosetting mold, it is possible to reduce man-hours such as taking in and out of the curing tank. The first resin 3 and the second resin 8 may be the same material.

  By filling the inside of the enclosure part with the second resin 8, the pair of surfaces of the enclosure part can restrain the second resin 8 in a state parallel to the optical axis of the optical fiber 1. . For this reason, since the second resin 8 is formed substantially symmetrically with respect to the optical axis of the optical fiber 1, the expansion or contraction of the second resin 8 occurs evenly with respect to the optical axis of the optical fiber 1. For this reason, the positional deviation of the front-end | tip part of the optical fiber 1 becomes small.

  When there is no enclosing portion, the positional fluctuation of the tip of the optical fiber 1 is the distance from one surface of the side frames of the resin frame 4 facing the optical fiber 1 to the optical fiber 1 and the other. The amount is proportional to the difference from the distance from the surface to the optical fiber 1, and the position variation of the tip of the optical fiber 1 increases. On the other hand, in the case where the surrounding portion is provided, the thermal deformation of the second resin 8 with respect to the temperature change is restricted by the pair of opposing surfaces, so that the positional fluctuation of the tip end portion of the optical fiber 1 The amount is proportional to the difference between the distance from the bottom surface 5 a to the optical fiber 1 and the distance from the eaves surface 5 c to the optical fiber 1.

In the present embodiment, in order to reduce the positional deviation of the distal end portion of the optical fiber 1, the engagement portion between the optical fiber 1 and the light receiving element 2 is positioned between the bottom surface 5a and the eave surface 5c. The lead frame 5 is bent. That is, the engaging portions are provided so that the distances from the respective surfaces of the bottom surface 5a and the eave surface 5c, which are a pair of surfaces, are equal. The distance from the eaves surface 5c to the optical fiber 1 at the engaging portion is defined as d1, and the distance from the bottom surface 5a to the optical fiber 1 at the engaging portion is defined as d2. The position of the engaging portion is set so that d1 and d2 have substantially the same length. The difference between at least d1 and d2 is desirably about 0.1 mm or less. Even when a silicone resin having a linear expansion coefficient of about 1 × 10 ⁻⁴ [1 / K] is used as the second resin 8 by setting the difference between d1 and d2 to be 0.1 mm or less, for example, temperature fluctuation 45 The positional deviation of the tip of the optical fiber 1 with respect to ° C. can be suppressed to about 5 μm, and a decrease in optical coupling efficiency between the optical fiber 1 and the light receiving element 2 can be suppressed.

  It should be noted that the mounting location of the light receiving element 2 is preferably the midpoint of the side frame of the resin frame 4. Thereby, it is possible to prevent the optical fiber 1 from being displaced in the lateral direction of the resin frame 4 due to the thermal deformation of the second resin 8. Further, the eaves surface 5 c may not be formed by bending the lead frame 5. For example, a new member may be attached as an eave surface by bonding or welding.

  As described above, the surrounding portion surrounding the engaging portion is provided, and the surrounding portion is filled with the second resin 8, so that the first resin that covers the outside of the optical fiber 1 and the light receiving element 2 due to a change in ambient temperature. Even when the third resin 8 and the second resin 8 are thermally deformed, the positional deviation of the tip of the optical fiber 1 with respect to the light receiving element 2 can be suppressed, so that the change in the optical coupling efficiency between the optical fiber 1 and the light receiving element 2 is small, and the temperature It is possible to obtain an optical semiconductor module having stable characteristics even when changing. Further, the surrounding portion can be formed by bending the lead frame 5 using a mold or the like. For this reason, it is not necessary to perform a plurality of members or complicated machining, and the surrounding portion can be easily manufactured.

  Note that by using an edge-emitting laser diode or a surface-emitting laser diode instead of the light receiving element 2, the optical semiconductor module can be configured as a light emitting module.

Embodiment 2. FIG.
FIG. 4 is a configuration diagram of an optical semiconductor module according to the second embodiment for carrying out the present invention. FIG. 5 is a BB cross-sectional view of the optical semiconductor module shown in FIG. 4 and 5, the structure of the surrounding portion is different from that of the first embodiment. 4 and FIG. 5, the same reference numerals as those in FIG. 1 and FIG. 2 are the same or corresponding parts, and this is common throughout the entire specification. Moreover, the aspect of the component which appears in the whole specification is an illustration to the last, and is not limited to these description. In FIG. 4, the eaves surface 11 c of the lead frame 11 shows only the outer shape.

  In the first embodiment, the engaging portion between the optical fiber 1 and the light emitting element 2 is surrounded by an enclosing portion configured by a pair of surfaces and three side surfaces, and the enclosing portion is filled with the second resin. . In the present embodiment, as shown in FIGS. 4 and 5, both sides, which are a second pair of surfaces that are substantially perpendicular to the side surface 11b and the pair of surfaces, ie, the bottom surface 11a and the eaves surface 11c, are opposed to each other. Surfaces 11d and 11e were added to this enclosure. Thereby, five surfaces other than the direction in which the optical fiber 1 extends can be surrounded.

  FIG. 6 is a perspective view of the lead frame in the second embodiment. The surrounding portion is formed by a lead frame 11 which is a metal member. A portion of the flat portion of the lead frame 11 is cut and raised by approximately 90 degrees, and the tip side of the cut and raised portion is bent. Furthermore, the surrounding part is formed by bending both sides of the cut-and-raised part toward the engaging part. The encircling portion is a bottom surface 11a that is a part of the flat portion of the lead frame 11 that is not cut and raised, and an eaves that is formed to be parallel to the bottom surface 11a on the tip side of the cut and raised portion of the lead frame 11. The surface 11c is composed of a side surface 11b which is the bottom surface 11a side of the cut and raised portion of the lead frame 11, and both side surfaces 11d and 11e where both sides of the cut and raised portion on the tip side are bent.

  The pair of surfaces and the second pair of surfaces of the enclosing portion can restrain the transparent resin in a state parallel to the optical axis of the optical fiber 1. By providing such an enclosing portion, the second resin 8 is constrained in the enclosing portion, and the second resin 8 is formed almost symmetrically with respect to the optical axis of the optical fiber 1. 8 expansion or contraction occurs evenly with respect to the optical axis of the optical fiber 1. For this reason, the positional deviation of the front-end | tip part of the optical fiber 1 becomes small.

  In the present embodiment, in order to reduce the positional deviation of the distal end portion of the optical fiber 1, the engagement portion between the optical fiber 1 and the light receiving element 2 is positioned between the bottom surface 11a and the eave surface 11c. The lead frame 11 is bent. That is, the engaging portion is provided so that the distances from the respective surfaces of the bottom surface 11a and the eave surface 11c, which are a pair of surfaces, are equal. The distance between the eaves surface 11c and the optical fiber 1 at the engaging portion is defined as d1, and the distance between the bottom surface 11a and the optical fiber 1 at the engaging portion is defined as d2. The position of the engaging portion is set so that d1 and d2 have substantially the same length. By setting at least the difference between d1 and d2 to about 0.1 mm or less, for example, the positional deviation of the tip of the optical fiber 1 with respect to a temperature fluctuation of 45 ° C. can be suppressed to about 5 μm.

  Further, the shape of the cut-and-raised portion of the lead frame 11 is set so that the engaging portion between the optical fiber 1 and the light receiving element 2 is positioned at the center of the opposite side surfaces 11d and 11e, and bending is performed. May be. That is, the engaging part is provided so that the distance from each surface of the both side surfaces 11d and 11e which are the second pair of surfaces is equal. Thereby, even when the first resin 3 and the second resin 8 are thermally deformed, it is possible to further suppress the positional deviation of the tip of the optical fiber 1 with respect to the light receiving element 2.

  With the configuration as described above, even when the first resin 3 and the second resin 8 that cover the outside of the optical fiber 1 and the light receiving element 2 are thermally deformed, the position of the tip of the optical fiber 1 relative to the light receiving element 2 is shifted. Therefore, it is possible to obtain an optical semiconductor module in which the optical coupling efficiency between the optical fiber 1 and the light receiving element 2 is small and the characteristics are stable even when the temperature changes.

Embodiment 3 FIG.
FIG. 7 is a perspective view of a lead frame according to Embodiment 3 for carrying out the present invention. In the present embodiment, only the configuration of the lead frame is different from that of the second embodiment. Also in the present embodiment, the engagement portion between the optical fiber 1 and the light receiving element 2 can be surrounded by the surrounding portion on five surfaces other than the direction in which the optical fiber 1 extends. In the present embodiment, both side surfaces 12d and 12e, which are the second pair of surfaces, are constituted by two surfaces formed by cutting and raising the flat portions on both sides of the bottom surface 12a.

  The surrounding portion is formed by a lead frame 12 which is a metal member. A part of the flat portion of the lead frame 12 is cut and raised by approximately 90 degrees, and the tip side of the cut and raised part is bent. Further, the encircling portion is formed by cutting and raising two of the flat portions different from the cut and raised portions. The encircling portion is a bottom surface 12a that is a part of the flat portion of the lead frame 12 that is not cut and raised, and an eaves that is formed to be parallel to the bottom surface 12a on the tip side of the cut and raised portion of the lead frame 12. The side surface 12c, the side surface 12b which is the bottom surface 12a side of the cut and raised portion of the lead frame 12, and both side surfaces 12d and 12e formed by cutting and raising the flat portion of the lead frame 12 different from the side surface 12b on both sides of the bottom surface 12a. It is constituted by. The enclosure is filled with a second resin 8.

  With the configuration as described above, even when the first resin 3 and the second resin 8 that cover the outer sides of the optical fiber 1 and the light receiving element 2 are thermally deformed, it is possible to suppress the displacement of the tip portion of the optical fiber 1. Thus, an optical semiconductor module having little change in optical coupling efficiency between the optical fiber 1 and the light receiving element 2 and having stable characteristics even when the temperature changes can be obtained.

Embodiment 4 FIG.
FIG. 8 is a configuration diagram of an optical semiconductor module according to Embodiment 4 for carrying out the present invention. In FIG. 8, the installation form of the optical semiconductor element is different from that of the first embodiment. In the present embodiment, a heat dissipating submount 21 is provided on the bottom surface 5a of the lead frame 5 which is one of a pair of surfaces, and an edge emitting laser diode which is an optical semiconductor element is provided on the submount 21. 22 is installed. That is, the edge-emitting laser diode 22 is mounted via the submount 21 on the bottom surface 5a which is one of a pair of surfaces. After the edge-emitting laser diode 22 is wire-bonded, the optical fiber 1 is aligned, and the tip of the optical fiber 1 and the edge-emitting laser diode 22 are fixed with the first resin 23. A portion engaged by the first resin 23 is an engaging portion. Then, after the side surface 5b and the eaves surface 5c are formed by cutting and raising the flat portion of the lead frame 5, a part of the optical fiber 1, the submount 21, the edge-emitting laser diode 22, and the first resin 23 are removed. 2 with resin 8.

  In order to reduce the displacement of the tip of the optical fiber 1, the leads are arranged so that the engaging portion between the optical fiber 1 and the edge-emitting laser diode 22 is located between the bottom surface 5 a and the eave surface 5 c. The frame 5 may be bent, or the height of the submount 21 may be adjusted.

  With the configuration as described above, even when the first resin 23 and the second resin 8 that cover the outside of the optical fiber 1 and the light receiving element 2 are thermally deformed, it is possible to suppress the displacement of the tip portion of the optical fiber 1. Therefore, it is possible to obtain an optical semiconductor module in which the optical coupling efficiency between the optical fiber 1 and the edge emitting laser diode 22 is small and the characteristics are stable even when the temperature changes.

It is a block diagram of the optical semiconductor module which shows Embodiment 1 of this invention. It is AA sectional drawing of the optical semiconductor module shown in FIG. It is a perspective view of the lead frame in Embodiment 1 of this invention. It is a block diagram of the optical semiconductor module which shows Embodiment 2 of this invention. It is BB sectional drawing of the optical semiconductor module shown in FIG. It is a perspective view of the lead frame in Embodiment 2 of this invention. It is a perspective view of the lead frame which shows Embodiment 3 of this invention. It is sectional drawing of the optical semiconductor module which shows Embodiment 4 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Optical fiber, 2 Light receiving element, 3,23 1st resin, 4 Resin frame, 5, 11, 12 Lead frame, 5a, 11a, 12a Bottom surface, 5b, 11b, 12b Side surface, 5c, 11c, 12c Eave surface, 6,7 Lead, 8 Second resin, 11d, 11e, 12d, 12e Both sides, 21 Submount, 22 End-emitting laser diode.

Claims (12)

Optical fiber,
An optical semiconductor element optically coupled to the optical fiber;
An engaging portion in which the optical fiber and the optical semiconductor element are engaged by a first resin;
An enclosing portion that surrounds the engaging portion with a side surface facing the engaging portion and a pair of surfaces substantially perpendicular to the side surface and facing each other across the optical semiconductor element;
A second resin filled in the enclosure,
An optical semiconductor module, wherein the optical semiconductor element is attached to the enclosure. 2. The optical semiconductor module according to claim 1, wherein the engaging portions are provided so that distances from the respective surfaces of the pair of surfaces are equal. 3. The optical semiconductor module according to claim 1, wherein the enclosing portion is provided with a second pair of surfaces that are substantially perpendicular to the side surfaces and the pair of surfaces and face each other. 4. The optical semiconductor module according to claim 3, wherein the engaging portions are provided so that the distances from the respective surfaces of the second pair of surfaces are equal. 5. The enclosure is formed by a metal member,
The pair of surfaces is constituted by a bottom surface that is a flat portion of the metal member and a surface that is formed to be parallel to the bottom surface at the tip side of the portion where the metal member is cut and raised,
3. The optical semiconductor module according to claim 1, wherein a side surface is constituted by a surface on the bottom surface side of the cut and raised portion. The enclosure is formed by a metal member,
The pair of surfaces is constituted by a bottom surface that is a flat portion of the metal member and a surface that is formed to be parallel to the bottom surface at the tip side of the portion where the metal member is cut and raised,
The side surface is constituted by a surface on the bottom side of the cut and raised portion,
5. The second pair of surfaces are configured by surfaces formed by bending both sides of the cut-and-raised portion on the front end side to the engaging portion side, respectively. 6. Optical semiconductor module. The enclosure is formed by a metal member,
The pair of surfaces is constituted by a bottom surface that is a flat portion of the metal member and a surface that is formed to be parallel to the bottom surface at the tip side of the portion where the metal member is cut and raised,
The side surface is constituted by a surface on the bottom side of the cut and raised portion,
5. The optical semiconductor module according to claim 3, wherein the second pair of surfaces are configured by surfaces formed by cutting and raising flat portions on both sides of the bottom surface. 6. 8. The optical semiconductor module according to claim 5, wherein the metal member is a lead frame. The optical semiconductor module according to any one of claims 1 to 8, wherein the optical semiconductor element is mounted on one or a side surface of the pair of surfaces. 10. The optical semiconductor module according to claim 1, wherein a photodiode is used as the optical semiconductor element. 10. The optical semiconductor module according to claim 1, wherein the optical semiconductor element is an edge-emitting laser diode or a surface-emitting laser diode. The optical semiconductor module according to any one of claims 1 to 11, wherein the first resin and the second resin are made of the same material.

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