Photoelectric hybrid substrate, photoelectric conversion module, optical communication device, and electronic device

Abstract

To provider a photoelectric hybrid substrate relatively excellent in electrical characteristics, mechanical strength, and production stability.SOLUTION: A photoelectric hybrid substrate 1 comprises an optical waveguide 2 and an electrical circuit board 3 toward one side in a thickness direction. The electrical circuit board 3 is provided with a metal support substrate 4, a base insulating layer 5, and a conductive layer 6 in order toward one side in the thickness direction. The electrical circuit board 3 is provided with the metal support substrate 4, the base insulating layer 5, and the conductive layer 6 in order toward one side in the thickness direction. The conductive layer 6 is provided with a second terminal 62, a third terminal 63, and an external substrate connection wiring 65. The metal support substrate 4 is provided with a plurality of wiring openings 31. The wiring openings 31 are formed over between the second and third terminals 62 and 63 to overlap in the thickness direction. The wiring openings 31 are spaced apart from each other in a direction intersecting an extending direction of the external substrate connection wiring 65. The metal support substrate 4 is disposed between the wiring openings 31.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optoelectronic hybrid board, an optoelectronic conversion module, an optical communication device, and an electronic device. [Background technology]

[0002] Conventionally, an optoelectronic hybrid board has been known. The optoelectronic hybrid board includes, for example, a flexible wiring board, a metal support layer, and an optical waveguide film. The flexible wiring board includes, for example, an insulating layer and a wiring layer.

[0003] More specifically, the following optical-electrical hybrid board has been proposed. The optical-electrical hybrid board includes an insulating layer, an electric circuit section provided on a first surface of the insulating layer, a metal reinforcing layer provided on a second surface of the insulating layer, and an optical waveguide provided on the second surface of the insulating layer and arranged so as to overlap the metal reinforcing layer. The electric circuit section includes pads on which elements are mounted, differential wiring, and connection terminals connected to the wiring board. A strip-shaped removed portion is formed in the metal reinforcing layer. The strip-shaped removed portion is arranged in a portion facing the differential wiring. The strip-shaped removed portion improves the electrical characteristics of the differential signal wiring section. A plurality of strip-shaped removed portions are formed according to the number of differential wirings. Furthermore, the strip-shaped removed portions are integrated into one from the connection terminal side connected to the wiring board toward the pad side for mounting an optical element or a driving IC (see, for example, Patent Document 1 (FIG. 8)). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2021 / 261428 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-described optoelectronic hybrid board, the strip-shaped removed portion provides relatively excellent electrical characteristics (i.e., signal transmission characteristics). On the other hand, the optoelectronic hybrid board is required to have relatively excellent mechanical strength and production stability even when the strip-shaped removed portion is formed.

[0006] An optoelectronic hybrid substrate is required to have relatively excellent electrical properties, relatively excellent mechanical strength, and relatively excellent production stability.

[0007] The present invention provides an optoelectronic hybrid substrate, an optoelectronic conversion module, an optical communication device, and an electronic device that combine relatively excellent electrical properties, relatively excellent mechanical strength, and relatively excellent production stability. [Means for solving the problem]

[0008] The present invention [1] includes an optoelectronic hybrid substrate including an optical waveguide and an electric circuit board, in that order in one thickness direction, wherein the optical waveguide includes an overclad, a core, and an underclad, in one thickness direction, and the electric circuit board includes a metal supporting board, an insulating layer, and a conductor layer, in that order in one thickness direction, and the conductor layer includes an element terminal for electrically connecting to an optical communication element, an external board terminal for electrically connecting to an external board, and a plurality of wirings that electrically connect the element terminal and the external board terminal, the metal supporting board has a plurality of openings that form pairs with the plurality of wirings, and each of the openings is formed over the entire area between the element terminal and the external board terminal, and the openings and the wirings that form pairs are arranged to overlap each other in the thickness direction, and the plurality of openings are arranged spaced apart from each other in a direction intersecting the extension direction of the wiring, and the metal supporting board is arranged between the plurality of openings.

[0009] In the above-mentioned optoelectronic hybrid board, the metal supporting board has a plurality of openings paired with a plurality of wirings, each opening being formed over the entire area between the element terminal and the external board terminal, and each opening and each wiring that form a pair are arranged to overlap each other in the thickness direction, thereby obtaining relatively excellent electrical characteristics.

[0010] Furthermore, in the above-mentioned optoelectronic hybrid board, the plurality of openings are arranged spaced apart from one another in a direction intersecting the direction in which the wiring extends, and a metal supporting substrate is arranged between the plurality of openings, so that the above-mentioned optoelectronic hybrid board can achieve relatively excellent mechanical strength and relatively excellent production stability.

[0011] That is, the above-described optoelectronic hybrid board has relatively excellent electrical properties, relatively excellent mechanical strength, and relatively excellent production stability.

[0012] The present invention [2] includes the optoelectronic hybrid board according to the above [1], in which the wiring is a differential wiring or a clock wiring.

[0013] In the above-mentioned optoelectronic hybrid board, if the wiring is differential wiring or clock wiring, relatively better electrical characteristics are required. In contrast, in the above-mentioned optoelectronic hybrid board, since a plurality of openings are formed to form pairs with a plurality of wirings, excellent electrical characteristics can be obtained.

[0014] The present invention [3] includes the optoelectronic hybrid substrate according to the above [1] or [2], wherein the optical communication element is at least one selected from the group consisting of a light receiving element, a light emitting element, a driving element, and an amplifying element.

[0015] In the above-mentioned optoelectronic hybrid board, when the optical communication element is at least one selected from the group consisting of a light receiving element, a light emitting element, a driving element, and an amplifying element, excellent electrical characteristics are required for the multiple wirings electrically connecting the element terminals and the external board terminals. In contrast, the above-mentioned optoelectronic hybrid board has multiple openings formed therein that form pairs with the multiple wirings, thereby achieving excellent electrical characteristics.

[0016] The present invention [4] includes the optoelectronic hybrid board according to any one of the above [1] to [3], wherein at least a part of the opening is filled with a resin.

[0017] In the above-described optoelectronic hybrid board, if at least a part of the opening is filled with resin, the wiring can be supported by the resin, and therefore, superior mechanical strength can be obtained.

[0018] The present invention [5] includes the optoelectronic hybrid board according to the above [4], in which the resin is the same as the material of the underclad.

[0019] In the above-described optoelectronic hybrid board, if the resin filled in the opening is the same as the material of the underclad, the adhesion between the electric circuit board and the optical waveguide can be improved.

[0020] The present invention [6] includes the optoelectronic hybrid board according to the above [4] or [5], in which the resin is the same as the material of the insulating layer.

[0021] In the above-described optoelectronic hybrid board, if the resin filled in the opening is the same as the material of the insulating layer, the adhesion between the electric circuit board and the optical waveguide can be improved.

[0022] The present invention [7] includes the optoelectronic hybrid board according to any one of the above [1] to [6], wherein a part of the opening is closed by the metal supporting board.

[0023] In the above-described optoelectronic hybrid board, if a part of the opening is closed by the metal supporting board, better mechanical strength can be obtained.

[0024] The present invention [8] includes the optoelectronic hybrid substrate described in [7] above, in which the metal supporting substrate that blocks part of the opening is arranged in a linear pattern along a direction perpendicular to the direction in which the wiring extends.

[0025] In the above-described optoelectronic hybrid board, if the metal supporting board is arranged in a linear pattern along a direction perpendicular to the extending direction of the wiring, better mechanical strength can be obtained.

[0026] The present invention [9] includes the optoelectronic hybrid board according to the above [7], wherein the metal supporting boards that close a part of the opening are arranged in a dot pattern.

[0027] In the above-described photoelectric hybrid board, if the metal supporting board is arranged in a dot pattern, better mechanical strength can be obtained.

[0028] The present invention

[10] includes the optoelectronic hybrid board according to any one of the above [7] to [9], wherein the wiring includes at least a pair of differential wirings, the differential wirings having a first wiring and a second wiring, and the metal supporting substrate that closes a part of the opening is disposed between the first wiring and the second wiring.

[0029] In the above-described optoelectronic hybrid board, if the metal supporting board is disposed between the first wiring and the second wiring of the differential wiring, better mechanical strength can be obtained.

[0030] The present invention

[11] includes the optoelectronic hybrid board according to any one of the above [1] to

[10] , wherein the metal supporting board further has a second opening around the element terminal.

[0031] In the above-described optoelectronic hybrid board, if the metal supporting board has the second opening, the terminal vicinity opening 33 can reduce the weight and improve the electrical characteristics, while maintaining relatively excellent mechanical strength.

[0032] The present invention

[12] includes an optoelectronic conversion module comprising the optoelectronic hybrid substrate according to any one of the above [1] to

[11] , the optical communication element electrically connected to the element terminal, and an external substrate electrically connected to the external substrate terminal.

[0033] The photoelectric conversion module includes the photoelectric hybrid substrate, and therefore has relatively excellent electrical characteristics, relatively excellent mechanical strength, and relatively excellent production stability.

[0034] The present invention

[13] includes an optical communication device comprising the photoelectric conversion module according to the above

[12] and an optical transmission line connected to the photoelectric conversion module.

[0035] The optical communication device includes the photoelectric conversion module, and therefore has relatively excellent electrical properties, relatively excellent mechanical strength, and relatively excellent production stability.

[0036] The present invention

[14] includes an electronic device comprising the optical communication device described in

[13] above.

[0037] The electronic device includes the optical communication device, and therefore has relatively excellent electrical properties, relatively excellent mechanical strength, and relatively excellent production stability. [Effects of the Invention]

[0038] In the optoelectronic hybrid board, optoelectronic conversion module, optical communication device, and electronic device of the present invention, the metal supporting board has a plurality of openings that form pairs with a plurality of wirings. Each opening is formed over the entire area between the element terminal and the external board terminal. Each opening and each wiring that form a pair are arranged so as to overlap in the thickness direction, and the plurality of openings are arranged spaced apart from each other in a direction intersecting the direction in which the wirings extend. Furthermore, a metal supporting board is arranged between the plurality of openings.

[0039] Therefore, the above-mentioned optoelectronic hybrid board, optoelectronic conversion module, optical communication device, and electronic device have relatively excellent electrical properties, relatively excellent mechanical strength, and relatively excellent production stability. [Brief explanation of the drawings]

[0040] [Figure 1] FIG. 1 is a cross-sectional view (cross-sectional view taken along line XX in FIG. 2A) along the longitudinal direction of an embodiment of a photoelectric conversion module in which a first element and a second element are mounted on a photoelectric hybrid substrate. [Figure 2] Fig. 2A is a plan view of one embodiment of a photovoltaic conversion module as viewed from one side in the thickness direction, and Fig. 2B is a plan view of a metal supporting board provided in the photovoltaic conversion module as viewed from the other side. [Figure 3] FIG. 3 is a plan view showing a first modified example of the wiring opening. [Figure 4] FIG. 4 is a plan view showing a first modified example of the wiring opening. [Figure 5] FIG. 5 is a plan view showing a second modified example of the wiring opening. [Figure 6] FIG. 6 is a plan view showing a third modified example of the terminal vicinity opening. [Figure 7] FIG. 7 is a plan view showing a fourth modified example of the terminal vicinity opening portion. [Figure 8] FIG. 8 is a cross-sectional view along the longitudinal direction of another embodiment of the photovoltaic conversion module. DETAILED DESCRIPTION OF THE INVENTION

[0041] 1. One embodiment An embodiment of an optoelectronic hybrid board, an optoelectronic conversion module, an optical communication device, and an electronic device will be described with reference to FIGS. 1, 2A, and 2B.

[0042] (1) Optoelectronic hybrid board (1-1) Overall structure The optoelectronic hybrid board 1 includes an optical waveguide 2 and an electric circuit board 3 arranged in this order in one direction in the thickness direction. The optoelectronic hybrid board 1 has a flat plate shape extending from one side to the other in the longitudinal direction perpendicular to the thickness direction. Each of these components will be described in detail below.

[0043] (1-2) Optical waveguide The optical waveguide 2 is the other side portion in the thickness direction of the optoelectronic hybrid substrate 1. The optical waveguide 2 is provided throughout the entire optoelectronic hybrid substrate 1, from one side to the other in the longitudinal direction of the optoelectronic hybrid substrate 1. The optical waveguide 2 includes an overclad 23, a core 22, and an underclad 21, which are arranged in this order toward one side in the thickness direction of the optoelectronic hybrid substrate 1.

[0044] The underclad 21 is disposed on the other surface of a metal supporting board 4 (described later) of the electric circuit board 3. The underclad 21 has the same shape as the outer shape of the optical waveguide 2 in plan view.

[0045] The core 22 is disposed on the other side in the thickness direction of the underclad 21. More specifically, the core 22 is formed in a prismatic shape extending along the longitudinal direction. The multiple cores 22 are disposed in parallel and spaced apart from one another in the width direction of the underclad 21 (a direction perpendicular to both the thickness direction and the longitudinal direction). The number of cores 22 is, for example, the same as the number of light receiving sections or light emitting sections of the first element 7 (described below), and is, for example, four in FIG. 2A .

[0046] A mirror 24 is also formed in the core 22. The mirror 24 is disposed opposite a light receiving portion or a light emitting portion of a first element 7 (described later) in the thickness direction of the optoelectronic hybrid substrate 1. An optical signal optically transmitted through the core 22 to one side in the longitudinal direction undergoes optical path conversion by the mirror 24 and is received by the light receiving portion of the first element 7. An optical signal emitted from the light emitting portion of the first element 7 also undergoes optical path conversion by the mirror 24, enters the core 22, and is optically transmitted via the core 22 to the other side in the longitudinal direction.

[0047] The overclad 23 is disposed on the other side in the thickness direction of the underclad 21. The overclad 23 also covers the core 22.

[0048] Examples of materials for the underclad 21, the core 22, and the overclad 23 include resins, more specifically transparent resins. Examples of transparent resins include epoxy resins, acrylic resins, and silicone resins. From the viewpoint of optical signal transmission, epoxy resins are preferred. The material for the core 22 has a higher refractive index than the materials for the underclad 21 and the overclad 23. The thickness of the optical waveguide 2 is, for example, 10 μm or more, and, for example, 200 μm or less.

[0049] (1-3) Electric circuit board The electric circuit board 3 is located on one side in the thickness direction of the optoelectronic hybrid board 1, and is disposed on one surface in the thickness direction of the optical waveguide 2. The electric circuit board 3 is provided over the entire optoelectronic hybrid board 1 from one side to the other in the longitudinal direction of the optoelectronic hybrid board 1. The electric circuit board 3 includes, in order toward one side in the thickness direction of the optoelectronic hybrid board 1, a metal supporting board 4, a base insulating layer 5 as an insulating layer, a conductor layer 6, and a cover insulating layer 12.

[0050] The metal supporting board 4 is disposed on one surface in the thickness direction of the optical waveguide 2. The metal supporting board 4 improves the mechanical strength of the electric circuit board 3. The metal supporting board 4 has a generally flat plate shape extending from one side to the other in the longitudinal direction.

[0051] Examples of materials for the metal supporting board 4 include metal materials. Examples of metal materials include 42 alloy, aluminum, copper-beryllium, phosphor bronze, copper, silver, aluminum, and stainless steel. From the viewpoint of mechanical strength, stainless steel is preferable. The thickness of the metal supporting board 4 is, for example, 3 μm or more, preferably 10 μm or more, and for example, 100 μm or less, preferably 50 μm or less.

[0052] The metal supporting board 4 has a plurality of openings, namely, openings 31 for wiring, in order to improve electrical characteristics. The metal supporting board 4 also has openings 32 for optical signals, separate from the openings 31 for wiring, in order to pass optical signals, which will be described later. The openings 31 for wiring and the openings 32 for optical signals will be described later in detail.

[0053] The insulating base layer 5 is disposed on one surface in the thickness direction of the metal supporting board 4. The insulating base layer 5 is provided over the entire optoelectronic hybrid substrate 1 from one side to the other in the longitudinal direction of the optoelectronic hybrid substrate 1. Examples of materials for the insulating base layer 5 include polyimide. The thickness of the insulating base layer 5 is, for example, 2 μm or more and, for example, 50 μm or less.

[0054] The conductor layer 6 is disposed on one surface in the thickness direction of the insulating base layer 5. Examples of the material for the conductor layer 6 include conductive materials. Examples of conductive materials include copper. The thickness of the conductor layer 6 is, for example, 2 μm or more and, for example, 20 μm or less.

[0055] The conductor layer 6 includes a plurality of terminals 80 and wiring 90 that connects the plurality of terminals 80 together.

[0056] The multiple terminals 80 include a first terminal 61, a second terminal 62, and a third terminal 63. The first terminal 61, the second terminal 62, and the third terminal 63 are arranged in order toward one side of the longitudinal direction of the electric circuit board 3, with a gap between them.

[0057] The first terminal 61 is an element terminal for electrically connecting to a first element 7 (described later).

[0058] 2A, a plurality of first terminals 61 are arranged so as to be included in the first element 7 in a plan view in order to electrically connect to the electrodes 71 of the first element 7. More specifically, the plurality of first terminals 61 are arranged side by side in the width direction, with a pair of first terminals 61 adjacent to each other in the longitudinal direction being defined as a first terminal pair 61P. The first terminal pairs 61P are arranged so that an optical signal whose optical path has been changed by the mirror 24 or an optical signal emitted from the light-emitting portion of the first element 7 can pass between the first terminal pairs 61P. More specifically, in the first terminal pair 61P, the first terminal 61 on one side in the longitudinal direction and the first terminal 61 on the other side in the longitudinal direction are arranged in parallel and spaced apart in the longitudinal direction so as to straddle an optical signal opening 32 (described below).

[0059] The second terminal 62 is an element terminal for electrically connecting to a second element 8 (described later).

[0060] The second terminal 62 is arranged on one side in the longitudinal direction relative to the first terminal 61. The second terminals 62 are arranged so as to be included in the second element 8 in a plan view in order to be electrically connected to the electrodes 81 of the second element 8. In detail, the second terminals 62 are arranged such that a pair of second terminals 62 adjacent to each other in the longitudinal direction constitutes a second terminal pair 62P, and the second terminal pairs 62P are arranged side by side in the width direction.

[0061] The third terminal 63 is an external board terminal for electrically connecting to an external board 10 (described later).

[0062] The third terminal 63 is arranged on one side in the longitudinal direction relative to the second terminal 62. The third terminal 63 is arranged on the opposite side of the first terminal 61 relative to the second terminal 62 in the longitudinal direction. A plurality of third terminals 63 are arranged so as to be included in the external substrate 10 in a plan view in order to electrically connect to the electrodes 11 of the external substrate 10. More specifically, the plurality of third terminals 63 are arranged side by side in the width direction.

[0063] A plating layer 9 is provided on each terminal 80. Examples of materials for the plating layer 9 include gold, silver, tin, tin alloys, and nickel.

[0064] The wiring 90 includes a plurality of inter-element connection wirings 64 and a plurality of external substrate connection wirings 65 .

[0065] The inter-element connection wiring 64 is a wiring for electrically connecting a first element 7 (described later) and a second element 8 (described later). That is, the inter-element connection wiring 64 is a wiring for connecting element terminals, and more specifically, a wiring for connecting a first terminal 61 as an element terminal and a second terminal 62 as an element terminal.

[0066] The inter-element connection wiring 64 is arranged to extend along the longitudinal direction. The inter-element connection wiring 64 is electrically connected to a first terminal 61 on one side in the longitudinal direction and a second terminal 62 on the other side in the longitudinal direction. More specifically, the inter-element connection wiring 64 is electrically connected to the first terminal 61 and the second terminal 62 that are adjacent to each other along the longitudinal direction.

[0067] The inter-element connection wiring 64 is, for example, a differential wiring, a clock wiring, or other signal wiring. The inter-element connection wiring 64 is preferably a differential wiring or a clock wiring, and more preferably a differential wiring.

[0068] The external substrate connection wiring 65 is a wiring for electrically connecting the second element 8 (described later) and the external substrate 10 (described later). That is, it is a wiring for electrically connecting the second terminal 62 as an element terminal and the third terminal as an external substrate terminal.

[0069] The external substrate connection wiring 65 is arranged to extend along the longitudinal direction. The external substrate connection wiring 65 is electrically connected to the second terminal 62 and the third terminal 63 on one side in the longitudinal direction. More specifically, the external substrate connection wiring 65 is electrically connected to the second terminal 62 and the third terminal 63 that are adjacent to each other along the longitudinal direction.

[0070] The external substrate connection wiring 65 is, for example, a differential wiring, a clock wiring, or other signal wiring. The external substrate connection wiring 65 is preferably a differential wiring or a clock wiring, and more preferably a differential wiring. In FIG. 2A, the external substrate connection wiring 65 is a differential wiring, and is depicted as two (two pairs (four wires)) wires.

[0071] The insulating cover layer 12 is disposed on one surface in the thickness direction of the conductor layer 6. Examples of materials for the insulating cover layer 12 include resins such as polyimide. The insulating cover layer 12 has a thickness of, for example, 2 μm or more and, for example, 50 μm or less.

[0072] (1-4) Wiring opening The metal supporting board 4 has a plurality of openings 31 for wiring.

[0073] The wiring opening 31 is a through hole having a generally rectangular shape in a plan view. The wiring openings 31 are arranged in parallel and spaced apart from one another in the width direction (i.e., the direction perpendicular to both the direction in which the external substrate connection wiring 65 extends and the thickness direction).

[0074] More specifically, the number of wiring openings 31 is the same as the number of external substrate connection wirings 65, and each wiring opening 31 forms a pair with an external substrate connection wiring 65. For example, in Fig. 2A, the external substrate connection wirings 65 are depicted as two (i.e., two pairs (four)) differential wirings, and in Fig. 2A, the wiring openings 31 are depicted as two through holes.

[0075] Each wiring opening 31 is formed over the entire area between the second terminal 62 and the third terminal 63, and overlaps in the thickness direction with the entire external substrate connection wiring 65 that forms a pair with itself.

[0076] That is, the second terminal 62 and the metal supporting board 4 overlap in the thickness direction. Also, the third terminal 63 and the metal supporting board 4 overlap in the thickness direction. On the other hand, the external board connection wire 65 does not overlap with the metal supporting board 4, but overlaps with the wiring opening 31.

[0077] More specifically, each wiring opening 31 is arranged so as to overlap in the thickness direction only with one external substrate connection wiring 65 that forms a pair with it. Note that each wiring opening 31 does not overlap with other external substrate connection wirings 65. In other words, only the respective wiring openings 31 and the respective external substrate connection wirings 65 that form a pair with each other overlap in the thickness direction.

[0078] Furthermore, a metal supporting board 4 is disposed between adjacent wiring openings 31 in the width direction. That is, the metal supporting board 4 is disposed along the longitudinal direction between adjacent wiring openings 31, and separates the multiple wiring openings 31 from one another.

[0079] Each wiring opening 31 is filled with the same resin as the material of the underclad 21. The same resin as the material of the underclad 21 is integrated with the underclad 21 within the wiring opening 31. In other words, a portion of the underclad 21 is filled in the wiring opening 31, and the external substrate connection wiring 65 is supported by the underclad 21 in place of the metal supporting board 4.

[0080] (1-5) Optical signal aperture The metal supporting board 4 has a plurality of openings 32 for optical signals.

[0081] The optical signal opening 32 is a through hole having a generally rectangular shape in a plan view. The multiple optical signal openings 32 are arranged in parallel and spaced apart from each other in the width direction (i.e., the direction perpendicular to both the direction in which the external substrate connection wiring 65 extends and the thickness direction).

[0082] More specifically, the number of optical signal openings 32 is the same as the number of light receiving sections (not shown) or light emitting sections (not shown) of first element 7 (described later), and each optical signal opening 32 is paired with a light receiving section (not shown) or light emitting section (not shown) of first element 7 (described later). For example, in Fig. 2A, first element 7 (described later) is depicted as an optical communications element having four light receiving sections (not shown) or light emitting sections (not shown), and in Fig. 2A, optical signal openings 32 are depicted as four through holes.

[0083] Each optical signal opening 32 is arranged so as to be included in a first element 7 (described later) in a plan view, and overlaps in the thickness direction with a light receiving portion (not shown) or a light emitting portion (not shown) of the first element 7 (described later) that is paired with it. Furthermore, each optical signal opening 32 overlaps in the thickness direction only with a light receiving portion (not shown) or a light emitting portion (not shown) of the first element 7 (described later) that is paired with it, and does not overlap with other light receiving portions (not shown) or light emitting portions (not shown). In other words, each optical signal opening 32 and each light receiving portion (not shown) or light emitting portion (not shown) that is paired with it are arranged so as to overlap in the thickness direction.

[0084] Furthermore, a metal supporting board 4 is disposed between adjacent optical signal openings 32 in the width direction. That is, the metal supporting board 4 is disposed along the longitudinal direction between adjacent optical signal openings 32, and separates the multiple optical signal openings 32 from one another.

[0085] Each opening 32 for an optical signal is filled with the same resin as the material of the underclad 21. The same resin as the material of the underclad 21 is integrated with the underclad 21 within the opening 32 for an optical signal. In other words, the opening 32 for an optical signal is filled with a portion of the underclad 21.

[0086] (1-6) Photoelectric conversion module The photoelectric conversion module 100 includes the above-described photoelectric hybrid substrate 1, a first element 7 electrically connected to the plurality of first terminals 61, a second element 8 electrically connected to the plurality of second terminals 62, and an external substrate 10 electrically connected to the plurality of third terminals 63. The first element 7 and the second element 8 are optical communication elements. The optical communication element is selected from the group consisting of a light receiving element, a light emitting element, a driving element, and an amplifying element.

[0087] More specifically, the first element 7 is at least one of a light-receiving element and a light-emitting element. The light-receiving element has a light-receiving section (not shown) and converts an optical signal received by the light-receiving section from the optical waveguide 2 via the mirror 24 into an electrical signal. An example of the light-receiving element is a photodiode (PD). The light-emitting element has a light-emitting section (not shown) and converts an electrical signal into an optical signal, which is emitted from the light-emitting section and transmitted to the optical waveguide 2 via the mirror 24. An example of the light-emitting element is a vertical-cavity surface-emitting laser (VCSEL). The first element 7 is mounted on the optoelectronic hybrid substrate 1 by electrically connecting the electrode 71 to the first terminal 61.

[0088] The second element 8 is at least one of a driving element and an amplifying element. The driving element receives a power supply current (power) and drives the light-emitting element. An example of the driving element is a driving IC (DRIVER). The amplifying element amplifies the electrical signal transmitted from the light-receiving element. An example of the amplifying element is a transimpedance amplifier (TIA). The second element 8 is mounted on the optoelectronic hybrid board by electrically connecting the electrode 81 to the second terminal 62.

[0089] The external substrate 10 is a component separate and independent from the optoelectronic hybrid substrate 1 and the optoelectronic conversion module 100. An example of the external substrate 10 is a printed circuit board. The external substrate 10 is connected to the optoelectronic hybrid substrate 1 by electrically connecting the electrode 11 to the third terminal 63. For example, the electrode 11 is connected to the third terminal 63 via a joining member 15 (solder).

[0090] When the first element 7 is a light receiving element, an amplifying element is mounted on the second element 8. In this case, the photoelectric conversion module 100 converts an optical signal into an electrical signal. When the first element 7 is a light emitting element, a driving element is mounted on the second element 8. In this case, the photoelectric conversion module 100 converts an electrical signal into an optical signal.

[0091] When the first element 7 is a light receiving element, an optical signal transmitted from the optical transmission path 14 indicated by a dashed line enters the other longitudinal end of the core 22 of the optical waveguide 2 of the optoelectric conversion module 100 via the optical connector 13 indicated by a dashed line. The optical signal then passes through the core 22 of the optical waveguide 2 and is transmitted to one longitudinal side, reaching the mirror 24. The optical path of the optical signal is then converted perpendicularly to one thickness side at the mirror 24, and the optical signal enters the light receiving portion of the light receiving element disposed on one thickness side of the mirror 24. The optical signal is converted into an electrical signal at the light receiving element. The electrical signal is then transmitted to the amplifier element via the inter-element connecting wiring 64. The electrical signal from the amplifier element is transmitted to the external substrate 10 via the external substrate connecting wiring 65.

[0092] When the first element 7 is a light-emitting element, an electrical signal transmitted from the external substrate 10 is first transmitted to the driving element via the external substrate connecting wiring 65. The electrical signal is then transmitted from the driving element to the light-emitting element via the inter-element connecting wiring 64. In the light-emitting element, the electrical signal is converted into an optical signal. Then, the optical signal is emitted perpendicularly from the light-emitting portion of the optical element to the other side in the thickness direction and reaches the mirror 24. In the mirror 24, the optical signal is optically path-converted to the other side in the longitudinal direction and enters one side in the longitudinal direction of the core 22 of the optical waveguide 2. The optical signal is then transmitted through the core 22 to the other end in the longitudinal direction of the core 22 and transmitted to the optical transmission line 14 via the optical connector 13.

[0093] (1-7) Method for manufacturing photoelectric hybrid board and photoelectric conversion module The following describes an example of a method for manufacturing the above-mentioned optoelectronic hybrid substrate 1 and optoelectronic conversion module 100. To prepare the optoelectronic hybrid substrate 1, first, an electric circuit board 3 is prepared, and then the optical waveguide 2 is formed on the electric circuit board 3.

[0094] To prepare the electric circuit board 3, first, the metal supporting board 4 is prepared, and then the insulating base layer 5, the conductor layer 6, and the insulating cover layer 12 are formed in this order on one side of the metal supporting board 4 in the thickness direction.

[0095] More specifically, in preparing the electric circuit board 3, first, a metal supporting board 4 made of a metal sheet is prepared. Next, a base insulating layer 5 is formed on one thickness-wise surface of the metal supporting board 4 by a known method (e.g., photolithography). Next, a conductor layer 6 is formed on one thickness-wise surface of the base insulating layer 5 by a known method (e.g., additive method). Next, a cover insulating layer 12 is formed on one thickness-wise surface of the conductor layer 6 by a known method (e.g., photolithography). Thereafter, the conductor layer 6 is plated to form a plating layer 9. Next, the metal supporting board 4 is cut from the other thickness-wise side to penetrate the metal supporting board 4 and expose the base insulating layer 5. That is, an opening 32 for an optical signal and an opening 31 for a wiring are formed. In this manner, the electric circuit board 3 is prepared.

[0096] Next, the optical waveguide 2 is formed on the electric circuit board 3. For example, by applying a photosensitive resin composition containing the above-mentioned transparent resin material and by photolithography, the underclad 21, core 22, and overclad 23 are formed in this order on the other side in the thickness direction of the electric circuit board 3. At this time, when the underclad 21 is formed, the opening 32 for an optical signal and the opening 31 for wiring are filled with resin. Thereafter, a mirror 24 is formed on the optical waveguide 2 including the core 22 by laser processing or cutting processing. In this manner, the optical waveguide 2 is prepared. Furthermore, together with the optical waveguide 2, the optoelectronic hybrid substrate 1 is manufactured.

[0097] Thereafter, the first element 7 and the second element 8 are mounted on the optoelectronic hybrid substrate 1, and an external substrate 10 is connected, thereby manufacturing the optoelectronic conversion module 100. On the optoelectronic hybrid substrate 1, the first element 7 is mounted on the first terminal 61, and the second element 8 is mounted on the second terminal 62 in a conventional manner. In addition, the external substrate 10 is connected to the third terminal 63. In this manner, the optoelectronic conversion module 100 is manufactured.

[0098] (1-7) Effects of this embodiment [1] In the optoelectronic hybrid substrate 1, the metal supporting board 4 has a plurality of wiring openings 31 that are paired with a plurality of external substrate connection wirings 65, and each wiring opening 31 is formed over the entire area between the second terminal 62 as an element terminal and the third terminal 63 as an external substrate terminal, and each wiring opening 31 and each external substrate connection wiring 65 that are paired with each other are arranged to overlap in the thickness direction. Therefore, relatively excellent electrical characteristics can be obtained.

[0099] Furthermore, in the above-described optoelectronic hybrid substrate 1, the plurality of wiring openings 31 are arranged spaced apart from one another in a direction intersecting the direction in which the external substrate connection wiring 65 extends. A metal supporting board 4 is arranged between the plurality of wiring openings 31. Therefore, the above-described optoelectronic hybrid substrate 1 can achieve relatively excellent mechanical strength and relatively excellent production stability.

[0100] That is, the above-described optoelectronic hybrid board 1 has relatively excellent electrical characteristics, relatively excellent mechanical strength, and relatively excellent production stability.

[0101] [2] In the above-described optoelectronic hybrid substrate 1, if the external substrate connection wiring 65 is a differential wiring or a clock wiring, even more excellent electrical characteristics are required. In contrast, in the above-described optoelectronic hybrid substrate 1, a plurality of wiring openings 31 are formed to form pairs with a plurality of external substrate connection wirings 65, and therefore excellent electrical characteristics can be obtained.

[0102] [3] In the above-described optoelectronic hybrid substrate 1, when the first element 7 and the second element 8 serving as optical communication elements are at least one selected from the group consisting of a light receiving element, a light emitting element, a driving element, and an amplifying element, excellent electrical characteristics are required for the plurality of external substrate connection wirings 65 that electrically connect the second terminal 62 and the third terminal 63. In contrast, in the above-described optoelectronic hybrid substrate 1, a plurality of wiring openings 31 that form pairs with the plurality of external substrate connection wirings 65 are formed, and therefore excellent electrical characteristics can be obtained.

[0103] [4] In the above-described optoelectronic hybrid substrate 1, if at least a portion of the wiring opening 31 is filled with resin, the external substrate connection wiring 65 can be supported by the resin, thereby obtaining superior mechanical strength.

[0104] [5] In the above-described optoelectronic hybrid board 1, if the resin filled in the wiring opening 31 is the same as the material of the underclad, the adhesion between the electric circuit board 3 and the optical waveguide can be improved.

[0105]

[12] The above-described photoelectric conversion module 100 includes the above-described photoelectric hybrid substrate 1, and therefore has relatively excellent electrical characteristics, relatively excellent mechanical strength, and relatively excellent production stability.

[0106] (1-8) Variations In the following modifications, the same components as those in the above-described embodiment are designated by the same reference numerals, and detailed descriptions thereof will be omitted. Furthermore, each modification can achieve the same effects as those in the above-described embodiment unless otherwise specified. Furthermore, the embodiment and its modifications can be combined as appropriate.

[0107] In the above embodiment, the entire wiring opening 31 is filled with resin, but for example, the wiring opening 31 does not have to be filled with resin. Also, for example, only a portion of the wiring opening 31 may be filled with resin. Preferably, at least a portion of the wiring opening 31 is filled with resin, and more preferably, the entire wiring opening 31 is filled with resin.

[0108] In the above-described optoelectronic hybrid board 1, if resin is filled in at least a part of the wiring opening, the external substrate connection wiring 65 can be supported by the resin, and therefore, better mechanical strength can be obtained.

[0109] Furthermore, when the wiring opening 31 is not filled with resin in part or in whole, the wiring opening 31 may be hollow in part or in whole.

[0110] Furthermore, when the wiring opening 31 is not filled with resin in part or in whole, the wiring opening 31 may be closed in part or in whole by something other than resin. For example, the wiring opening 31 may be closed in part or in whole by the metal supporting board 4. Preferably, the wiring opening 31 is closed in part by the metal supporting board 4.

[0111] 3, in the first modified example, the metal supporting board 4 closes a part of the wiring opening 31. In the first modified example, the metal supporting board 4 closing a part of the wiring opening 31 is arranged in a linear pattern along the direction in which the external substrate connection wiring 65 extends (that is, the longitudinal direction).

[0112] That is, in the first modified example, the external substrate connection wiring 65 includes at least one pair of differential wiring. More specifically, as shown in FIG. 2A, the external substrate connection wiring 65 is two pairs (four lines) of differential wiring. The differential wiring is a wiring pair consisting of two signal lines. The differential wiring includes a first wiring 651 and a second wiring 652 that extend parallel to each other.

[0113] 3, in the first modified example, the metal supporting board 4 that closes a part of the wiring opening 31 is disposed between the wire pair of the differential wiring, that is, between the first wiring 651 and the second wiring 652. In other words, the metal supporting board 4 separates the wiring opening 31 that overlaps with the first wiring 651 in the thickness direction from the wiring opening 31 that overlaps with the second wiring 652 in the thickness direction.

[0114] In the above-described optoelectronic hybrid board 1, if the metal supporting board 4 is disposed between the first wiring 651 and the second wiring 652 in the differential wiring, better mechanical strength can be obtained.

[0115] The arrangement of the metal supporting board 4 that closes a part of the wiring opening 31 is not limited to the above.

[0116] 4, in the second modification, the metal supporting board 4 that closes a part of the wiring opening 31 is arranged in a linear pattern along a direction (i.e., width direction) perpendicular to the extending direction of the external substrate connection wiring 65. Even in such an embodiment, the metal supporting board 4 that closes a part of the wiring opening 31 can provide better mechanical strength.

[0117] 5, for example, in the third modified example, the metal supporting boards 4 that close part of the wiring openings 31 are arranged in a dot pattern. Also in such an embodiment, the metal supporting boards 4 that close part of the wiring openings 31 can provide better mechanical strength.

[0118] In addition, in the above embodiment, the metal supporting board 4 has the opening 31 for wiring and the opening 32 for optical signal, but the metal supporting board 4 can further have a terminal vicinity opening 33 as a second opening different from these.

[0119] For example, in the fourth modification, as shown in FIG. 6, the metal supporting board 4 has one near-terminal opening 33 around the second terminal 62 (see the broken line in FIG. 6 (same below)) serving as the element terminal.

[0120] More specifically, in the fourth modification, the terminal vicinity opening 33 is formed in a generally frame shape in plan view. Furthermore, the terminal vicinity opening 33 is disposed so as to be included in the second element 8 and surround all of the second terminals 62 in plan view.

[0121] Furthermore, in the fourth modified example, the terminal vicinity opening 33 does not overlap with the second terminal 62 in the thickness direction. That is, in the fourth modified example, the second terminal 62 overlaps with the metal supporting board 4 in the thickness direction. In such an embodiment, the terminal vicinity opening 33 can reduce weight and improve electrical characteristics, while maintaining relatively excellent mechanical strength.

[0122] Furthermore, the number, shape and arrangement of the terminal vicinity openings 33 are not limited to those described above.

[0123] For example, in the fifth embodiment, as shown in FIG. 7, the metal supporting board 4 has a plurality of (for example, three) near-terminal openings 33 around the second terminal 62 (see dashed line in FIG. 7 (same below)) serving as an element terminal.

[0124] More specifically, in the fifth modified example, the terminal vicinity opening 33 is formed in a generally rectangular shape in plan view. Furthermore, the terminal vicinity opening 33 is arranged so as to be included in the second element 8 and adjacent to the second terminal 62 in plan view. That is, the three terminal vicinity openings 33 are formed so as to extend along the width direction, and are arranged at intervals in the longitudinal direction so as to sandwich the second terminal 62 in plan view.

[0125] Furthermore, in the fifth modified example, the terminal vicinity opening 33 does not overlap with the second terminal 62 in the thickness direction. That is, in the fifth modified example, the second terminal 62 overlaps with the metal supporting board 4 in the thickness direction. In such an embodiment, the terminal vicinity opening 33 can reduce weight and improve electrical characteristics, while maintaining relatively excellent mechanical strength.

[0126] Although not shown in detail, in addition to the above-described modifications, various other modifications may be made without impairing the excellent effects of the present invention.

[0127] For example, in the above embodiment, the wiring opening 31 is filled with the same resin as the material of the underclad 21, but for example, the wiring opening 31 may be filled with the same resin as the material of the base insulating layer 5. Even when the resin filled in the wiring opening 31 is the same as the material of the base insulating layer 5, the adhesion between the electric circuit board 3 and the optical waveguide 2 can be improved, just as in the case when the resin filled in the wiring opening 31 is the same as the material of the underclad 21.

[0128] Furthermore, for example, in the above embodiment (e.g., FIG. 2A), the multiple (e.g., two) wiring openings 31 have the same shape, but the multiple wiring openings 31 may have different shapes depending on the pattern of the external substrate connection wiring 65. Note that even in such a case, the wiring openings 31 are spaced apart from each other in a direction intersecting the direction in which the external substrate connection wiring 65 extends.

[0129] In the above embodiment, the photoelectric conversion module 100 is connected to the optical transmission line 14 via the optical connector 13, but the present invention is not limited to this.

[0130] As shown in Fig. 8, in the sixth modification, two photoelectric conversion modules 100a and 100b are connected to form an in-device photoelectric conversion module 101. The in-device photoelectric conversion module 101 is used in a data center, a single device, or the like. In this case, in Fig. 8, if the first element 7 on one side in the longitudinal direction is a light-emitting element 7a, the second element 8 is a driving element 8a, and the first element 7 on the other side in the longitudinal direction is a light-receiving element 7b, and the second element 8 is an amplifying element 8b.

[0131] In this case, an electrical signal transmitted from the external substrate 10a of the photoelectric conversion module 100a is transmitted to the driving element 8a via the external substrate connecting wiring 65a of the photoelectric conversion module 100a, and then transmitted to the light-emitting element 7a via the inter-element connecting wiring 64a. In the light-emitting element 7a, the electrical signal is converted into an optical signal, and the optical signal is emitted from the light-emitting portion toward the mirror 24a. The optical signal from the mirror 24a enters the core 22a, passes through the core 22a, reaches one longitudinal end of the core 22b of the photoelectric conversion module 100b, and then passes through the core 22b to the mirror 24b. The light-receiving element 7b receives the optical signal from the mirror 24b at its light-receiving portion and converts the optical signal into an electrical signal. The electrical signal is then transmitted from the light-receiving element 7b to the amplifier element 8b via the inter-element connecting wiring 64a, and then transmitted to the external substrate 10b via the external substrate connecting wiring 65b. In the in-device photoelectric conversion module 101, the multiple wirings 90a and multiple wirings 90b can be directly connected to transmit electrical signals in parallel with optical signals.

[0132] As described above, in the sixth modification, an electrical signal is converted into an optical signal, transmitted, and then the optical signal is converted back into an electrical signal, thereby enabling high-speed communication within the device.

[0133] 2. Devices equipped with photoelectric conversion modules (1) Optical communication devices The optical communication device includes the above-described photoelectric conversion module 100 and an optical transmission line 14 connected to the photoelectric conversion module 100. The optical transmission line 14 is usually connected via an optical connector 13. An example of the optical transmission line 14 is an optical fiber cable. The optical communication device is connected to, for example, another optical communication device via the optical transmission line 14.

[0134] Optical communication devices include, for example, active optical cables (AOCs) and optical transceivers.

[0135] The optical communication device includes the photoelectric conversion module 100, and therefore has relatively excellent electrical properties, relatively excellent mechanical strength, and relatively excellent production stability.

[0136] (2)Electronic equipment An electronic device includes the above-described photoelectric conversion module 100. Such an electronic device can transmit and receive optical signals at high speed within the device or between other electronic devices. The electronic device is suitable for use in data centers and other places where high-speed communication is required.

[0137] Examples of electronic equipment include servers and switches in a data center.

[0138] The electronic device includes the optical communication device, and therefore has relatively excellent electrical properties, relatively excellent mechanical strength, and relatively excellent production stability. [Explanation of symbols]

[0139] 1 Optoelectronic mixed board 2 Optical waveguide 3 Electrical circuit board 4 Metal Support Board 5 Base insulation layer 6 Conductor Layer 7 First element 8 Second element 9 Plating layer 10 External board 11 electrodes 12 Cover insulation layer 13 Optical Connector 14 Optical transmission line 15 Joint materials 21 Underclad 22 cores 23 Overclad 24. Mirror 31 Wiring opening 32 Optical signal aperture 33 Terminal vicinity opening 61 1st terminal 62 2nd terminal 63 3rd terminal 64 Inter-element connection wiring 65 External board connection wiring 71 Electrode 80 terminals 90 Wiring 100 Photoelectric conversion module

Claims

1. An optoelectronic hybrid board including an optical waveguide and an electric circuit board in this order in one direction of the thickness direction, The optical waveguide includes an overclad, a core, and an underclad in one thickness direction, the electric circuit board includes a metal supporting board, an insulating layer, and a conductor layer in this order in one thickness direction; the conductor layer includes an element terminal for electrically connecting to an optical communication element, an external substrate terminal for electrically connecting to an external substrate, and a plurality of wirings for electrically connecting the element terminal and the external substrate terminal; the metal supporting board includes a plurality of openings paired with a plurality of the wirings, Each of the openings is formed over the entire area between the element terminal and the external substrate terminal, the openings and the wirings that form a pair are arranged to overlap each other in the thickness direction, the plurality of openings are arranged spaced apart from one another in a direction intersecting the direction in which the wiring extends, the metal supporting board is disposed between the plurality of openings.

2. The optoelectronic hybrid board according to claim 1 , wherein the wiring is a differential wiring or a clock wiring.

3. 2. The optoelectronic hybrid board according to claim 1, wherein the optical communication element is at least one selected from the group consisting of a light receiving element, a light emitting element, a driving element, and an amplifying element.

4. The optoelectronic hybrid board according to claim 1 , wherein at least a portion of the opening is filled with a resin.

5. The optoelectronic hybrid board according to claim 4 , wherein the resin is the same material as the underclad.

6. The optoelectronic hybrid board according to claim 4 , wherein the resin is the same material as the insulating layer.

7. The optoelectronic hybrid board according to claim 1 , wherein a portion of the opening is closed by the metal supporting board.

8. the metal supporting board that closes a part of the opening, The optoelectronic hybrid board according to claim 7 , wherein the wiring is arranged in a linear pattern along a direction perpendicular to the direction in which the wiring extends.

9. the metal supporting board that closes a part of the opening, The optoelectronic hybrid board according to claim 7 , wherein the electrodes are arranged in a dot pattern.

10. the wiring includes at least one pair of differential wiring; the differential wiring includes a first wiring and a second wiring, The optoelectronic hybrid board according to claim 7 , wherein the metal supporting board that closes a part of the opening is disposed between the first wiring and the second wiring.

11. The metal supporting board further comprises The optoelectronic hybrid board according to claim 1 , further comprising a second opening around the element terminal.

12. The photoelectric hybrid substrate according to any one of claims 1 to 11, the optical communication element electrically connected to the element terminal; an external board electrically connected to the external board terminal; A photoelectric conversion module comprising:

13. The photoelectric conversion module according to claim 12; an optical transmission line connected to the photoelectric conversion module; An optical communication device comprising:

14. An electronic device comprising the optical communication device according to claim 13.

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