JP5267426B2 - Optical device mounting substrate, opto-electric hybrid substrate, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical element mounting substrate capable of achieving excellent optical connection to an optical waveguide, while securing sufficient conductivity of electric wires or insulation property between each electric wire, even when a plurality of light emitting/receiving parts are arranged highly densely; and to provide an optical/electrical hybrid substrate including the optical element mounting substrate, and an electronic device. <P>SOLUTION: The optical/electrical hybrid substrate 1 has an insulating substrate 11 having a through-hole 110, two light emitting/receiving elements 71, 72, a semiconductor element 8, a first wire 15 provided on the upper surface of the insulating substrate 11, and a second wire 16 provided on the under surface. The light emitting/receiving element 71 includes a plurality of light emitting/receiving parts 711 arrayed along a paper thickness direction of Fig.2. The light emitting/receiving element 71 is provided on the upper surface of the insulating substrate 11 and is connected electrically to the first wire 15. Meanwhile, the light emitting/receiving element 72 also includes a plurality of light emitting/receiving parts 721, and the light emitting/receiving element 72 is provided in the through-hole 110 and is connected electrically to the second wire 16. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an optical element mounting substrate, an opto-electric hybrid substrate, and an electronic device.

  In recent years, with the wave of computerization, wideband lines (broadband) capable of exchanging large amounts of information at high speed have been spreading. Also, as devices for transmitting information to these broadband lines, transmission devices such as router devices and WDM (Wavelength Division Multiplexing) devices are used. In these transmission apparatuses, a large number of signal processing boards in which arithmetic elements such as LSIs and storage elements such as memories are combined are installed, and each line is interconnected.

  Each signal processing board has a circuit in which arithmetic elements, storage elements, etc. are connected by electrical wiring. However, with the increase in the amount of information to be processed in recent years, each board has a very high throughput. It is required to transmit. However, with the speeding up of information transmission, problems such as generation of crosstalk and high-frequency noise, deterioration of electric signals, and mismatch of characteristic impedance are becoming apparent. For this reason, electrical wiring becomes a bottleneck, making it difficult to improve the throughput of the signal processing board.

  On the other hand, an optical communication technique for transferring data using an optical carrier wave has been developed, and in recent years, an optical waveguide is becoming popular as a means for guiding the optical carrier wave from one point to another point. This optical waveguide has a linear core part and a clad part provided so as to cover the periphery thereof. The core part is made of a material that is substantially transparent to the light of the optical carrier wave, and the cladding part is made of a material having a refractive index lower than that of the core part.

  In such an optical waveguide, light introduced from one end of the core portion is conveyed to the other end while being reflected at the boundary with the cladding portion. A light emitting element such as a semiconductor laser is disposed on the incident side of the optical waveguide, and a light receiving element such as a photodiode is disposed on the emission side. Light incident from the light emitting element propagates through the optical waveguide, is received by the light receiving element, and performs communication based on the blinking pattern of the received light.

  Recently, there has been a movement to replace electric wiring in a signal processing board with an optical waveguide. By replacing the electrical wiring with an optical waveguide, it is expected that the problem of the electrical wiring as described above will be solved and the signal processing board will be able to further increase the throughput.

  By the way, electric wiring for supplying electric power is indispensable for driving each element such as a light emitting element and a light receiving element which perform mutual conversion between an optical signal and an electric signal as well as an arithmetic element and a memory element. For this reason, electric wiring and an optical waveguide are mixedly mounted on the signal processing substrate, and development of such a substrate (photoelectric mixed substrate) is being promoted.

  For example, in Patent Document 1, an optical device and an electronic device are mixedly mounted on a mounting substrate having an optical waveguide formed therein, and the light emitting / receiving unit and the optical waveguide of the optical device are optically coupled by a total reflection mirror unit. A connected optoelectronic module is disclosed.

JP 2002-182049 A

  In addition, by increasing the number of channels of the optical waveguide, the density of modules is increasing. As the number of channels of the optical waveguide increases, it is necessary to increase the number of light emitting / receiving units mounted on the mounting substrate, and further, electric wiring for supplying power and control signals to the light emitting / receiving units is also required. It is necessary to increase the number according to the number of light emitting / receiving units.

  However, when the number of channels of the optical waveguide is increased in the module described in Patent Document 1, a plurality of light emitting / receiving portions and a plurality of electric wirings corresponding to the number of channels are arranged on the upper surface of the mounting substrate. In that case, there are the following problems.

  1. Since the space for arranging the electrical wiring is limited on the top surface of the mounting board, the wiring width and wiring spacing (line and space) must be narrowed, and the formation of electrical wiring is highly accurate. Required. As a result, the yield decreases and the manufacturing cost increases.

  2. Due to the limitation of line and space that can be realized when manufacturing the electrical wiring, the channel pitch of the optical waveguide on which the optical element mounting substrate can be stacked is also limited. For this reason, when the channel pitch of the optical waveguide to be connected is narrow, the conductivity of the electrical wiring and the insulation between the electrical wirings cannot be sufficiently ensured in the optical element mounting substrate connected to the optical waveguide.

  An object of the present invention is to provide a good optical connection to an optical waveguide while sufficiently ensuring the electrical conductivity of the electrical wiring and the insulation between the electrical wirings even when the plurality of light emitting and receiving parts are arranged at high density. It is an object to provide an optical element mounting substrate that enables the optical element mounting, and an opto-electric hybrid board and an electronic device including the optical element mounting substrate.

Such an object is achieved by the present inventions (1) to (16) below.
(1) an insulating substrate;
A plurality of light emitting / receiving sections that receive or emit light;
A first wiring provided on a first surface of the insulating substrate;
A second wiring provided on a second surface opposite to the first surface of the insulating substrate;
An optical element mounting substrate that is used to optically connect the plurality of light emitting / receiving portions and the plurality of channels by being laminated with an optical waveguide having a plurality of channels on the second surface side. There,
The plurality of light emitting / receiving units are arranged in two or more parallel rows in a plan view, and the light receiving / emitting units included in the first column that is one of the columns are the first wiring And the light emitting / receiving section included in the second column different from the first column is electrically connected to the second wiring. Mounting board.

(2) The insulating substrate has a through hole,
The light emitting / receiving section included in the second row is the optical element mounting substrate according to (1), which is provided in the through hole.

(3) The second wiring has an extended portion that extends in the vicinity of the opening of the through hole,
The optical element mounting substrate according to (2), wherein the light emitting / receiving units included in the second row and the second wiring are electrically connected to each other in the extended portion.

(4) The insulating substrate has a through hole and a through wiring provided in the through hole,
The light emitting / receiving units included in the second row are provided on the first surface side of the insulating substrate,
The optical element mounting substrate according to (1), wherein the light receiving and emitting units included in the second row and the second wiring are electrically connected via the through wiring.

  (5) The optical element mounting substrate according to any one of (1) to (4), wherein the first wiring and the second wiring are each extended in the same direction.

  (6) The projected images of the first wiring and the second wiring on the same plane parallel to the insulating substrate are at least partially overlapped with each other in any one of (1) to (5). Optical device mounting substrate.

  (7) The optical element mounting substrate according to any one of (1) to (6), wherein the plurality of light receiving and emitting units are all mounted on one optical element.

  (8) The optical element mounting substrate according to any one of (1) to (6), wherein the plurality of light receiving and emitting units are distributed and mounted on a plurality of optical elements.

  (9) The optical element mounting substrate according to (7) or (8), further including a frame-shaped substrate provided on the first surface side and configured to surround the entire circumference of the optical element.

  (10) The optical element mounting substrate according to (9), wherein the frame-shaped substrate is thicker than the optical element.

  (11) The optical element mounting substrate according to any one of (1) to (10), wherein an average thickness of the insulating substrate is 5 to 50 μm.

(12) having a control element that is provided on the first surface side of the insulating substrate and controls operations of the plurality of light emitting and receiving units;
Each of the first wiring and the second wiring is provided to connect the plurality of light emitting / receiving units and the control element,
The second wiring according to any one of (1) to (11), wherein an arrangement surface of the second wiring is changed from the second surface to the first surface in the middle of the second wiring. Optical element mounting substrate.

(13) The optical element mounting substrate according to any one of (1) to (12),
An optical waveguide comprising a plurality of channels and provided on the second surface side of the insulating substrate;
An opto-electric hybrid board comprising optical path changing means for optically connecting the plurality of light emitting / receiving sections and the plurality of channels.

  (14) The opto-electric hybrid board according to (13), wherein the optical element mounting substrate is laminated on one end portion or both end portions of the optical waveguide.

(15) The optical element mounting substrate is provided at one end of the optical waveguide,
The opto-electric hybrid board according to (13), further comprising a connector provided at the other end of the optical waveguide and connecting the optical waveguide to a connection partner.

  (16) An electronic apparatus comprising the opto-electric hybrid board according to any one of (13) to (15).

  According to the present invention, among the light emitting / receiving units arranged in two or more rows, the wiring for driving the light emitting / receiving unit included in one column and the light receiving / emitting unit included in a column different from this column are driven. Wiring is provided on different surfaces of the insulating substrate, so that a large number of light emitting / receiving portions can be arranged at high density without reducing the line and space of the wiring. . For this reason, the electrical conductivity of the electrical wiring and the insulation between the electrical wirings can be sufficiently ensured, and the performance of the optical element mounting substrate can be enhanced. In addition, it is possible to obtain an optical element mounting substrate that facilitates the formation of electrical wiring and enables reliable optical connection to an optical waveguide having a narrow channel pitch.

  Further, by providing such an optical element mounting substrate, an opto-electric hybrid substrate and an electronic device capable of high-density mounting can be obtained.

It is a perspective view which permeate | transmits and shows 1st Embodiment of the opto-electric hybrid board of this invention. FIG. 2 is a cross-sectional view of the opto-electric hybrid board shown in FIG. It is a top view which shows the wiring formed in the optical element mounting substrate of this invention. FIG. 4 is a partially enlarged view of FIG. 3. It is sectional drawing which shows the other structural example of the opto-electric hybrid board shown in FIG. It is a figure (sectional drawing) for demonstrating the manufacturing method of the opto-electric hybrid board shown in FIG. It is sectional drawing which shows typically 2nd Embodiment of the optical element mounting board | substrate and opto-electric hybrid board | substrate of this invention. It is sectional drawing which shows typically 3rd Embodiment of the opto-electric hybrid board | substrate of this invention. It is sectional drawing which shows typically 4th Embodiment of the optical element mounting board | substrate and opto-electric hybrid board | substrate of this invention. It is the (a) top view and (b) sectional view which show typically a 5th embodiment of the optical element mounting substrate and opto-electric hybrid board of the present invention. It is sectional drawing which shows the conventional opto-electric hybrid board provided with the conventional optical element mounting board | substrate. It is a top view which shows the wiring formed in the conventional optical element mounting substrate.

  Hereinafter, an optical element mounting substrate, an opto-electric hybrid board, and an electronic apparatus according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

<Opto-electric hybrid board>
(First embodiment)
First, a first embodiment of an optical element mounting substrate of the present invention and an opto-electric hybrid board of the present invention provided with the optical element mounting substrate will be described.

  1 is a partially transparent perspective view showing a first embodiment of the opto-electric hybrid board according to the present invention, FIG. 2 is a cross-sectional view taken along the line AA of the opto-electric hybrid board shown in FIG. 1, and FIG. FIG. 4 is a partially enlarged view of FIG. 3 and FIG. 5 is a cross-sectional view showing another configuration example of the opto-electric hybrid board shown in FIG. FIG. 6 is a diagram (sectional view) for explaining a method of manufacturing the opto-electric hybrid board shown in FIG. In the following description, the upper side of FIGS. 1 and 2 is referred to as “upper” and the lower side is referred to as “lower”. In each drawing, the thickness direction of each substrate is emphasized.

  An opto-electric hybrid board 1 shown in FIG. 1 is an optical element mounting board provided with an optical circuit layer 2 in which an optical waveguide 21 having a plurality of channels is formed, and a light receiving and emitting element (optical element) 7 provided above the optical circuit layer 2. 10 is laminated.

  Here, the optical circuit layer 2 has a long band shape, and the optical element mounting substrate 10 is laminated on the upper surface of one end of the optical circuit layer 2.

  The optical element mounting substrate 10 is provided on a flat insulating substrate 11, an insulating substrate 11, a frame substrate 12 having a rectangular frame shape, and an insulating substrate 11 inside the frame substrate 12. The light emitting / receiving element 7 and the semiconductor element (control element) 8 are provided.

  The light receiving / emitting element 7 converts the electrical signal into an optical signal, emits the optical signal from the light emitting unit, and enters the optical waveguide 21 or receives the optical signal emitted from the optical waveguide 21 by the light receiving unit. This is a light receiving element that converts it into an electrical signal. The light emitting / receiving element 7 shown in FIG. 2 includes two light emitting / receiving elements 71 and 72. Each of the light receiving / emitting elements 71 and 72 includes a plurality of light emitting / receiving units 711 and 721 provided on the lower surface thereof. And electrode pads 712 and 722 provided corresponding to the light emitting / receiving portions 711 and 721, respectively. Each of the light emitting / receiving units 711 and 721 emits an optical signal downward, or receives an optical signal going upward. In addition, the arrow shown in FIG. 2 is an example of an optical path when the light emitting / receiving elements 71 and 72 are both light emitting elements.

  On the other hand, in the optical waveguide 21, mirrors (optical path changing means) 22 are respectively provided below the light emitting / receiving units 711 and 721. The mirror 22 is configured to convert the optical path by 90 ° in order to optically connect the optical waveguide 21 extending in the left-right direction in FIG. 2 and the light receiving and emitting unit 711 provided on the optical element mounting substrate 10. . Through such a mirror 22, the optical signals emitted from the respective light emitting / receiving units 711, 721 are sent to the optical waveguide 21, or the optical signals propagated through the optical waveguide 21 are transmitted to the respective light receiving / emitting units 711, 711, 721 can be made incident.

  The semiconductor element 8 is an element having an electrode pad 812 provided on the lower surface thereof, and is an element that controls the operation of the light emitting / receiving element 7. When these elements operate cooperatively, the opto-electric hybrid board 1 performs mutual conversion between an optical signal and an electric signal, thereby enabling optical communication.

  A first wiring (electrical wiring) 15 is provided on the upper surface of the insulating substrate 11, and a second wiring (electrical wiring) 16 is provided on the lower surface. That is, electrical wirings insulated from each other are laid on both surfaces of the insulating substrate 11. Among these wirings, the electrode pad 712 of the light emitting / receiving element 71 is electrically connected to the first wiring 15, while the electrode pad 722 of the light receiving / emitting element 72 is electrically connected to the second wiring 16. ing.

  As described above, the electrical wiring (the first wiring 15 and the second wiring 16) connected to the two light emitting / receiving elements 71 and 72 is laid on different surfaces of the insulating substrate 11. Since there is a margin in the dimensional accuracy of the electrical wiring, the manufacturability is remarkably increased. In addition, since the space for laying the electrical wiring can be widened on each surface of the insulating substrate 11, restrictions on the width of the wiring and the interval between the wirings (line and space) are relaxed. As a result, sufficient electrical conductivity of the electrical wiring and insulation between the electrical wirings can be ensured.

  Hereinafter, each part of the opto-electric hybrid board 1 will be described in detail.

(Optical circuit layer)
The optical circuit layer 2 shown in FIG. 1 includes an optical waveguide 21 in which a clad layer (lower clad layer) 211, a core layer 213, and a clad layer (upper clad layer) 212 are laminated in this order from below. . Among these, as shown in FIG. 1, the core layer 213 is formed with a linear core portion 214 in a plan view and a side cladding portion 215 adjacent to the side surface of the core portion 214. In FIG. 1, the eight core portions 214 are provided in a straight line along the longitudinal direction of the optical circuit layer 2 having a strip shape so as to be arranged in parallel, and adjacent to the side surfaces of the respective core portions 214. A plurality of side clad portions 215 are provided. In FIG. 1, the cladding layer 212 is drawn in a transparent manner, and each core portion 214 is given a dot.

  In the optical waveguide 21 shown in FIG. 1, the light incident on one end of each core part 214 is transmitted at the interface between each core part 214 and the clad part (the clad layers 211 and 212 and the side clad parts 215). It can be totally reflected and propagated to the other end. Thereby, optical communication can be performed based on the blinking pattern of the light received at the emitting end. That is, the optical waveguide 21 is a multi-channel optical waveguide having a plurality of (eight in FIG. 1) channels (core portion 214) and capable of performing a plurality of optical communications in parallel.

  In order to cause total reflection at the interface between each core part 214 and the cladding part, a difference in refractive index needs to exist at the interface. The refractive index of the core part 214 may be larger than the refractive index of the cladding part, and the difference is not particularly limited, but is preferably 0.5% or more, more preferably 0.8% or more. On the other hand, the upper limit value may not be set, but is preferably about 5.5%. If the difference in refractive index is less than the lower limit, the effect of transmitting light may be reduced, and even if the upper limit is exceeded, no further increase in light transmission efficiency can be expected.

  The refractive index difference is expressed by the following equation, where A is the refractive index of the core portion 214 and B is the refractive index of the cladding portion.

Refractive index difference (%) = | A / B-1 | × 100
In the configuration shown in FIG. 1, each core portion 214 is formed in a straight line shape in a plan view, but may be curved or branched in the middle, and its shape is arbitrary.

  The cross-sectional shape of each core part 214 is generally a square such as a square or a rectangle (rectangle), but is not particularly limited, and is not limited to a perfect circle, a circle such as an ellipse, a rhombus, a triangle, It may be a polygon such as a pentagon.

  The width and height of each core part 214 are not particularly limited, but are preferably about 1 to 200 μm, more preferably about 5 to 100 μm, and still more preferably about 20 to 70 μm.

  The constituent material of the core layer 213 is not particularly limited as long as it has the above-described refractive index difference. Specifically, acrylic resin, methacrylic resin, polycarbonate, polystyrene, epoxy resin, polyamide, polyimide, polybenzo In addition to various resin materials such as oxazole, polysilane, polysilazane, and cyclic olefin resins such as benzocyclobutene resin and norbornene resin, there are glass materials such as quartz glass and borosilicate glass.

  Of these, norbornene resins are particularly preferable. These norbornene-based polymers include, for example, ring-opening metathesis polymerization (ROMP), combination of ROMP and hydrogenation reaction, polymerization by radical or cation, polymerization using a cationic palladium polymerization initiator, and other polymerization initiators ( For example, it can be obtained by any known polymerization method such as polymerization using a polymerization initiator of nickel or another transition metal).

  On the other hand, the clad layers 211 and 212 are positioned below and above the core layer 213, respectively, and together with the side clad portions 215, constitute clad portions that surround the outer periphery of the core portions 214. Thereby, the optical waveguide 21 functions as a light guide.

  The average thickness of the clad layers 211 and 212 is preferably about 0.1 to 1.5 times the average thickness of the core layer 213 (the average height of each core portion 214). More preferably, the average thickness of the clad layers 211 and 212 is not particularly limited, but is usually preferably about 1 to 200 μm and about 5 to 100 μm. More preferably, it is about 10 to 60 μm. Thereby, the function as a clad layer is suitably exhibited while preventing the optical circuit layer 2 from becoming unnecessarily large (thickened).

  Moreover, as a constituent material of each clad layer 211 and 212, the same material as the constituent material of the core layer 213 mentioned above can be used, for example, but a norbornene polymer is particularly preferable.

  Further, when selecting the constituent material of the core layer 213 and the constituent materials of the clad layers 211 and 212, the material may be selected in consideration of the difference in refractive index between them. Specifically, the refractive index of the constituent material of the core layer 213 is sufficiently larger than the refractive index of the cladding layers 211 and 212 in order to ensure total reflection of light at the boundary between the core layer 213 and the cladding layers 211 and 212. What is necessary is just to select a material so that it may become. As a result, a sufficient refractive index difference is obtained in the thickness direction of the optical circuit layer 2, and leakage of light from each core portion 214 to the cladding layers 211 and 212 can be suppressed.

  From the viewpoint of suppressing light attenuation, it is also important that the adhesiveness (affinity) between the constituent material of the core layer 213 and the constituent materials of the cladding layers 211 and 212 is high.

  Further, as described above, a plurality of mirrors 22 are provided in the middle of the optical waveguide 21 (see FIG. 2). This mirror 22 is formed on the inner wall surface of the space (cavity) obtained by digging in the middle of the optical waveguide 21. A part of this inner wall surface is a plane that crosses the core portion 214 at an angle of 45 °, and this plane becomes the mirror 22. The optical waveguide 21 and the light emitting / receiving units 711 and 721 are optically connected via the mirror 22.

  In addition, you may make it form a reflecting film in the mirror 22 as needed. As the reflective film, a metal film such as Au, Ag, or Al is preferably used.

(Optical device mounting substrate)
An optical element mounting substrate 10 is provided above the optical circuit layer 2.

  As described above, the optical element mounting substrate 10 includes the insulating substrate 11, the frame-shaped substrate 12, the light emitting / receiving element 7, and the semiconductor element 8.

  The insulating substrate 11 is provided such that the lower surface thereof faces the upper surface of the optical circuit layer 2. The light emitting / receiving element 7 (light emitting / receiving element 71 and light receiving / emitting element 72) and the semiconductor element 8 are formed of the insulating substrate. 11 is provided.

  Since the optical path connecting each of the light emitting / receiving portions 711 and 721 and the optical waveguide 21 penetrates the insulating substrate 11 in the thickness direction, the insulating substrate 11 is made of a light-transmitting material. Is preferred. Thereby, the transmission characteristic of the optical path is improved. In the case where the insulating substrate 11 is made of a material with low translucency, a through hole may be provided in accordance with the optical path.

  The insulating substrate 11 is preferably flexible. Thereby, the adhesiveness with respect to the optical waveguide 21 becomes high. This is because the insulating substrate 11 having flexibility has high shape followability, and thus exhibits excellent adhesion even if the upper surface of the optical waveguide 21 is not a flat surface. Further, even when the opto-electric hybrid board 1 is bent, the insulating substrate 11 can also be bent in accordance with the curve of the optical waveguide 21, thereby preventing a decrease in adhesion. Furthermore, since it is difficult for a gap to occur at the close contact interface, there is an advantage that a reduction in transmission efficiency on the optical path is prevented.

  Further, the flexible material selected as the constituent material of the insulating substrate 11 has an intermediate coefficient of thermal expansion between the constituent material of the frame-like substrate 12 described later and the constituent material of the optical circuit layer 2 (optical waveguide material). The insulating substrate 11 is positioned as an intermediate layer between the frame-shaped substrate 12 and the optical circuit layer 2 because many of them exhibit a typical value. That is, the flexible insulating substrate 11 has a function of relieving deformation stress generated between the layers. As a result, the insulating substrate 11 can be reliably peeled off or broken due to thermal history by relaxing the accumulation of stress generated between the layers based on the difference in thermal expansion in the manufacturing process, mounting process, or actual use environment. Can be prevented.

  The Young's modulus (tensile modulus) of the insulating substrate 11 is preferably about 1 to 20 GPa and more preferably about 2 to 12 GPa in a general room temperature environment (around 20 to 25 ° C.). . If the range of the Young's modulus is this level, the insulating substrate 11 has sufficient flexibility to obtain the above-described effects.

  Examples of the material constituting such an insulating substrate 11 include various resin materials such as polyimide resins, polyamide resins, epoxy resins, various vinyl resins, and polyester resins such as polyethylene terephthalate resins. Of these, those mainly composed of a polyimide resin are preferably used. The polyimide resin is particularly suitable as a constituent material of the insulating substrate 11 because it has high heat resistance and excellent translucency and flexibility.

  Specific examples of the insulating substrate 11 include a film substrate used for a polyester copper clad film substrate, a polyimide copper clad film substrate, an aramid copper clad film substrate, and the like.

  Moreover, although the average thickness of the insulating substrate 11 is not particularly limited, it is preferably about 5 to 50 μm, and more preferably about 10 to 40 μm. The insulating substrate 11 having such a thickness has sufficient flexibility regardless of the constituent material. If the thickness of the insulating substrate 11 is within the above range, the opto-electric hybrid board 1 can be thinned, and the distance between the light emitting / receiving unit 711 and the optical waveguide 21 can be sufficiently shortened. The transmission loss of the insulating substrate 11 is suppressed.

  Furthermore, if the thickness of the insulating substrate 11 is within the above range, it is possible to prevent the transmission efficiency from being lowered due to the divergence of the optical signal. For example, after propagating through the optical waveguide 21, the light reflected upward by the mirror 22 can reach the light emitting / receiving unit 711 before being widely diffused. For this reason, it can prevent that the light quantity which reaches | attains the light emitting / receiving part 711 reduces, and can improve the S / N ratio of optical communication. For the above reason, a lens for converging the optical signal is not necessary, so that the structure of the opto-electric hybrid board 1 can be simplified and the manufacturing yield can be improved.

  On the other hand, when the light emitting / receiving unit 711 is a light emitting unit, the emitted light can be made to reach the mirror 22 before the emitted light diverges.

  A frame-shaped substrate 12 is laminated on the insulating substrate 11. Thereby, the frame-shaped substrate 12 reinforces the insulating substrate 11 and prevents deformation of the optical element mounting substrate 10 even when the insulating substrate 11 has flexibility.

  The frame substrate 12 is preferably composed of a substrate having higher rigidity than the insulating substrate 11. Specifically, the Young's modulus (flexural modulus) of the frame-shaped substrate 12 is preferably about 5 to 50 GPa in a general room temperature environment (around 20 to 25 ° C.), and is about 12 to 30 GPa. Is more preferable.

  Further, as described above, the frame-shaped substrate 12 is a substrate having a quadrangular frame shape, but this frame may not necessarily be a closed frame, but may be a partially opened frame. In this case, it is preferable that one of the four sides of the quadrangle is one side or less than the length thereof. Thereby, the frame-shaped board | substrate 12 can fully exhibit the effect mentioned above. Further, from the viewpoint of improving mounting accuracy and workability when mounting the frame-shaped substrate 12 on another electric substrate, the frame-shaped substrate 12 is provided with a concave portion, a convex portion, a hole portion or a notch portion for alignment. It may be.

  As a material constituting such a frame-shaped substrate 12, for example, paper, glass cloth, resin film or the like is used as a base material, and a phenol resin, polyester resin, epoxy resin, cyanate resin, polyimide is used as the base material. And those impregnated with a resin material such as a fluororesin and a fluororesin.

  Specifically, in addition to insulating substrates used in glass-based copper-clad laminates such as glass cloth and epoxy copper-clad laminates, and composite copper-clad laminates such as glass nonwoven fabrics and epoxy copper-clad laminates, polyethers Examples thereof include heat-resistant and thermoplastic organic rigid substrates such as imide resin substrates, polyetherketone resin substrates, and polysulfone resin substrates, and ceramic rigid substrates such as alumina substrates, aluminum nitride substrates, and silicon carbide substrates.

  The average thickness of the frame substrate 12 is not particularly limited, but is preferably about 300 μm to 3 mm, and more preferably about 500 μm to 2.5 mm. Since the frame-shaped substrate 12 having such a thickness has sufficient rigidity and is thicker than the general light emitting / receiving element 7 and the semiconductor element 8, they can be surely enclosed. As a result, the light emitting / receiving element 7 and the semiconductor element 8 are contained in the space 13 inside the frame-shaped substrate 12, and these elements are prevented from affecting the thickness of the entire opto-electric hybrid board 1. Is done. As a result, the opto-electric hybrid board 1 can be reliably reduced in thickness. Even when an external force is applied to the opto-electric hybrid board 1, the external force is received by the frame-like substrate 12, thereby preventing the external force from directly reaching the light emitting / receiving element 7 and the semiconductor element 8. As a result, it is possible to reliably prevent the light emitting / receiving element 7 and the semiconductor element 8 from being damaged or dropped off. In addition, as shown in FIG. 1, when the frame-shaped board | substrate 12 has comprised the closed frame shape, each element 7 and 8 can be protected also from the external force given from all directions.

  The frame substrate 12 may be a single substrate, but may be a multilayer substrate (build-up substrate) formed by laminating a plurality of substrates. In this case, a patterned conductive layer is included between the layers of the multilayer substrate, and an arbitrary electric circuit may be formed. Thereby, even if the frame-shaped board | substrate 12 is a small area, a complicated electrical circuit can be constructed | assembled inside and the density increase of a circuit is achieved.

  Further, as shown in FIGS. 1 and 2, the frame-shaped substrate 12 is provided with a plurality of columnar through-holes 121 penetrating in the thickness direction. These through-holes 121 are arranged in a line at equal intervals over the entire circumference of the frame-shaped substrate having a frame shape.

  Each through-hole 121 is filled with a conductive material, or a film of a conductive material is formed along the inner wall surface. Thereby, a through via structure 151 is formed in each through hole 121.

  A connection terminal 152 electrically connected to each through via structure 151 and a bump 153 provided on each connection terminal 152 are provided in the opening of each through hole 121 (in the vicinity of the upper opening end). Yes.

  On the other hand, a first wiring (electric wiring) 15 made of a conductive material is provided on the upper surface of the insulating substrate 11, and a similar second wiring 16 is provided on the lower surface of the insulating substrate 11. (The wirings 15 and 16 are omitted in FIG. 1).

  These wirings 15 and 16 connect the electrode pads 712 and 722 of the light emitting / receiving elements 71 and 72 and the electrode pads 812 of the semiconductor element 8 and the through via structures 151. Specifically, the light emitting / receiving element 71 is connected to the semiconductor element 8 and each through via structure 151 via the first wiring 15, and the light receiving / emitting element 72 is connected to the second wiring 16 via the second wiring 16. The semiconductor element 8 and each through via structure 151 are connected. Therefore, external driving power and control signals can be sent to the light emitting / receiving element 7 and the semiconductor element 8 via the bump 153, the connection terminal 152, the through via structure 151, and the first wiring 15.

  The second wiring 16 is provided on the lower surface of the insulating substrate 11 in the vicinity of the light emitting / receiving element 7, but the arrangement surface is between the light emitting / receiving element 7 and the semiconductor element 8. It is comprised so that it may move to the upper surface of. Specifically, the insulating substrate 11 is provided with a through wiring 161 penetrating in the thickness direction. The second wiring 16 is provided on the lower surface of the insulating substrate 11 in the vicinity of the light emitting / receiving element 7, and is provided on the upper surface of the insulating substrate 11 in the vicinity of the semiconductor element 8. And these are connected through the penetration wiring 161.

  The through wiring 161 is formed of a columnar body such as a cylinder or a prism, and the constituent material includes the same conductive material as that of the first wiring 15 and the second wiring 16.

  Here, the insulating substrate 11 is provided with a through hole 110 penetrating in the thickness direction. As shown in FIG. 2, a light emitting / receiving element 72 is inserted into the through hole 110.

  Further, below the through hole 110, the second wiring 16 extends so as to protrude in the vicinity of the opening of the through hole 110. In the case of FIG. 2, the second wirings 16 that are independent from the left and right of the through-hole 110 are extended so that the two second wirings 16 that extend from the left and right are separated from each other in the vicinity of the center of the opening. ing.

  Furthermore, since the light emitting / receiving element 72 is inserted into the through hole 110 and the second wiring 16 extends in the vicinity of the opening of the through hole 110, the extended portion is used as each electrode of the light emitting / receiving element 72. The light emitting / receiving element 72 and the second wiring 16 are electrically connected by contacting with the pad 722.

  3 shows each light emitting / receiving element 71, 72 in the optical element mounting substrate 10, each light receiving / emitting section 711, 721 and each electrode pad 712, 722, and the first wiring 15 and the second wiring 16 provided thereon. 2 is a plan view schematically showing through wiring 161 and semiconductor element 8. FIG.

  As described above, the light emitting / receiving element 71 has a plurality of light receiving / emitting portions 711, but in the case of FIG. 3, it has four light receiving / emitting portions 711 arranged in a row in the Y direction at equal intervals. ing. That is, the light emitting / receiving element 71 has a first row in which four light emitting / receiving sections 711 are arranged. Each light emitting / receiving unit 711 is provided with four electrode pads 712 arranged so as to surround each light emitting / receiving unit 711, and power and control signals are transmitted from these electrode pads 712 to the light emitting / receiving unit 711. The electrode pad 712 receives the received light signal from the light emitting / receiving unit 711.

  The first wiring 15 shown in FIG. 3 is connected to two electrode pads 712 connected to the light emitting / receiving unit 711 among the four electrode pads 712. As a result, the light emitting / receiving section 711 and the semiconductor element 8 are electrically connected by the eight first wirings 15 connected to the eight electrode pads 712.

  On the other hand, the light emitting / receiving element 72 has a plurality of light emitting / receiving portions 721 as in the case of the light emitting / receiving element 71, but in the case of FIG. Part 721. That is, the light emitting / receiving element 72 has a second row in which four light emitting / receiving portions 721 are arranged. Each light emitting / receiving unit 721 is provided with four electrode pads 722 arranged so as to surround each light emitting / receiving unit 721, and power and control signals are transmitted from these electrode pads 722 to the light emitting / receiving unit 721. The electrode pad 722 receives the received light signal from the light emitting / receiving unit 721.

  The second wiring 16 shown in FIG. 3 is connected to two electrode pads 722 connected to the light emitting / receiving section 721 among the four electrode pads 722. As a result, the light emitting / receiving unit 721 and the semiconductor element 8 are electrically connected by the eight second wirings 16 connected to the eight electrode pads 722.

  That is, the optical element mounting substrate 10 shown in FIG. 3 has a total of eight light emitting / receiving sections 711 and 721, and these are distributed to the two light emitting / receiving elements 71 and 72 by four.

  As described above, the light emitting / receiving element 71 and the light emitting / receiving element 72 have the rows of the light emitting / receiving portions 711 and 721 parallel to each other, but their positions in the Y direction are shifted from each other. As a result, when an imaginary line parallel to the X axis passing through the center of each of the light emitting / receiving units 711 and 721 (for example, a one-dot chain line shown in FIG. 4) is drawn, the eight imaginary lines have a predetermined interval. The amount of deviation in the Y direction between the light emitting / receiving element 71 and the light receiving / emitting element 72 is set.

  This interval (interval L in FIG. 4) is set to be equal to the channel pitch of the optical circuit layer 2 laminated with the optical element mounting substrate 10 (interval between the core portions 214). In the case of the optical element mounting substrate 10 shown in FIG. 4, by laminating with the optical circuit layer 2 having a channel pitch equal to the interval L, the positions of the light emitting / receiving portions 711 and 721 and the positions of the channels in the plan view are identical. In turn, these are optically connected to each other. In FIG. 4, the intervals between the eight virtual lines are all equal, but are appropriately set according to the channel pitch of the optical circuit layer 2 and may not be equal.

  As described above, in the optical element mounting substrate 10, the four light receiving / emitting portions 711 forming the first row and the four light receiving / emitting portions 721 forming the second row include the electrode pads 712 and 722 and the insulating property. Since it is connected to the semiconductor element 8 through electrical wiring (first wiring 15 and second wiring 16) laid on different surfaces of the substrate 11, eight electrical wirings are routed on each surface. It will do.

Here, a conventional optical element mounting substrate will be described.
FIG. 11 is a cross-sectional view showing a conventional opto-electric hybrid board including a conventional optical element mounting board, and FIG. 12 is a plan view showing wiring formed on the conventional optical element mounting board. 11 and 12 using the same reference numerals as those in FIGS. 2 to 4 are the same as the configurations of the respective parts in FIGS.

  An optical element mounting substrate 90 shown in FIG. 11 includes an insulating substrate 91, wirings 951 and 952 provided on the upper surface of the insulating substrate 91, and light receiving and emitting elements 7 (receiving and receiving elements) disposed above the insulating substrate 91. The light emitting element 71 and the light emitting / receiving element 72) and the semiconductor element 8 are included.

  Further, the opto-electric hybrid board 9 shown in FIG. 11 has an optical element mounting board 90 and an optical circuit layer 2 laminated on the lower surface thereof.

  12 is a plan view of the wiring formed on the optical element mounting substrate 90. FIG. 12 is the same as FIG. 4 except that the wiring laying pattern is different.

  In FIG. 12, wirings 951 are connected to the respective electrode pads 712 corresponding to the four light emitting / receiving units 721 forming the first column. On the other hand, wirings 952 are connected to the respective electrode pads 722 corresponding to the four light emitting / receiving units 721 forming the second column.

  In the conventional optical element mounting substrate 90, as shown in FIG. 12, since the wiring 951 and the wiring 952 are respectively laid on the same plane, a sufficient space is required for their routing. Specifically, in the optical element mounting substrate 90, as shown in FIG. 12, it is necessary to lay two wirings 952 in a gap between adjacent electrode pads 712. However, since the gap is very narrow, the width and interval (line and space) of the two wirings 952 are reduced, and the two wirings 952 are required to have extremely high dimensional accuracy. This dimensional accuracy must be higher as the channel pitch of the optical circuit layer 2 laminated on the optical element mounting substrate 90 becomes narrower. Due to this restriction, the conventional optical element mounting substrate 90 can be manufactured. It was extremely difficult. If the dimensional accuracy is not sufficient, the wiring 952 may be disconnected or short-circuited.

  Furthermore, since there is a limit to the dimensional accuracy that can be realized, the optical element mounting substrate 90 may not be connected to the optical circuit layer 2 having a high channel pitch.

  In addition, each wiring 952 can be laid so as to bypass the light emitting / receiving element 71, but in this case, the wiring length of each wiring 952 becomes remarkably long. As a result, the delay and loss of the signal transmitted through each wiring 952 increase, and the transmission characteristics of each wiring 952 are significantly deteriorated.

  In contrast, in the optical element mounting substrate 10 of the present invention, as shown in FIG. 4, although the first wiring 15 and the second wiring 16 extend in the same direction, the insulating substrate Since these are laid on 11 different surfaces, there is a margin in the space required for routing the wires 15 and 16. Therefore, even when a large number of light emitting / receiving sections 711 and 721 are arranged at high density, it is not necessary to make the line and space of the wirings 15 and 16 too small. For this reason, each wiring 15 and 16 becomes what has sufficient electroconductivity and insulation, As a result, the performance of the optical element mounting substrate 10 can be improved. Further, since the wirings 15 and 16 do not require high dimensional accuracy, there is an advantage that their manufacture becomes easy.

  Furthermore, as long as the dimensional accuracy is increased, the optical element mounting substrate 10 can be reliably connected to the optical circuit layer 2 having a narrower channel pitch than the conventional one. For this reason, the opto-electric hybrid board 1 capable of high-density mounting is obtained by using such an optical element mounting board 10.

  Further, when the second wiring 16 is laid, the electrode pads 722 and the semiconductor element 8 can be connected to each other with the shortest distance without considering the position of the light emitting / receiving element 71. As a result, the wiring length of the second wiring 16 can be further shortened, delay and loss of signals transmitted through the second wiring 16 are suppressed, and deterioration of transmission characteristics of the second wiring 16 is prevented. be able to.

  Furthermore, since the wiring surfaces of the wirings 15 and 16 are different, the projected images obtained by projecting the first wiring 15 and the second wiring 16 on the same surface overlap at least partially. Also good. In this case, since the design freedom of each of the wirings 15 and 16 is significantly improved as compared with the conventional case, the manufacturing of each of the wirings 15 and 16 becomes easier.

  In the case where the second wiring 16 is laid, it is preferable that the second wiring 16 is disposed avoiding a region corresponding to the light emitting / receiving portion 711 of the light emitting / receiving element 7. That is, it is preferable that the projected images formed by projecting the second wiring 16 and the light emitting / receiving unit 711 do not overlap. Thereby, it is possible to prevent the optical path between the light emitting / receiving unit 711 and the mirror 22 from interfering with the second wiring 16, and to avoid a decrease in the transmission characteristic of the optical path.

  Further, as described above, the light emitting / receiving element 72 is inserted into the through hole 110 provided in the insulating substrate 11 (see FIG. 2). For this reason, compared with the case where the light emitting / receiving element 72 is mounted on the upper surface of the insulating substrate 11, the wiring length of the second wiring 16 can be further shortened. This is because when the light emitting / receiving element 72 is placed on the upper surface of the insulating substrate 11, it is necessary to provide wiring penetrating the insulating substrate 11 or wiring laid to bypass the light receiving / emitting element 71. This is because the wiring length becomes longer, but when the light emitting / receiving element 72 is provided in the through hole 110, the wiring length can be shortened by at least the thickness of the insulating substrate 11. As a result, delay and loss of a signal transmitted through the second wiring 16 are suppressed, and deterioration in transmission characteristics of the second wiring 16 can be prevented.

  Further, by inserting the light emitting / receiving element 72 into the through hole 110, the positional accuracy of the light emitting / receiving element 72 with respect to the position of the second wiring 16 can be improved. That is, the position of the light emitting / receiving element 72 is inevitably restricted by the inner wall surface of the through-hole 110, and accordingly, the position of the light emitting / receiving unit 721 relative to the mirror 22 and the position of each electrode pad 722 are changed. The position of 2 with respect to the wiring 16 naturally matches. As a result, it is possible to prevent optical path transmission characteristics, contact failure, and the like due to positional deviation.

  In FIG. 3, the semiconductor element 8 is provided on the right side of the light emitting / receiving element 71. However, the position of the semiconductor element 8 is not limited to the position shown in FIG. May be on the opposite side, or may be shifted in the Y direction with respect to the light emitting / receiving element 7.

  Here, the first wiring 15 and the second wiring 16 are provided between the light emitting / receiving elements 71 and 72 and the semiconductor element 8, but the interval between the wirings increases toward the semiconductor element 8. It is gradually expanding. Therefore, the closer to the semiconductor element 8, the more margin is provided in the line and space of the wirings 15 and 16.

  Incidentally, as described above, the second wiring 16 is provided on the lower surface of the insulating substrate 11 in the vicinity of the light emitting / receiving element 72, but is provided on the upper surface of the insulating substrate 11 in the vicinity of the semiconductor element 8. These are connected via a through wiring 161 penetrating the insulating substrate 11. Here, the arrangement position of the through wiring 161 is preferably as close to the semiconductor element 8 as possible. In such a position, as described above, there is a margin in the line and space of each of the wirings 15 and 16, so that when the through wiring 161 is formed, the tolerance of the position accuracy of the formation position is relaxed. can do. Therefore, the ease of manufacture of the through wiring 161 is improved.

  As described above, the optical element mounting substrate 10 shown in FIG. 3 has eight light emitting / receiving portions 711 and 721, which are distributed to the two light emitting / receiving elements 71 and 72 by four. However, this distribution pattern is not particularly limited. For example, one light emitting / receiving section may be provided for each of eight light emitting / receiving elements, or two light receiving / emitting sections may be provided for each of four light emitting / receiving elements. All the light emitting / receiving units may be provided.

  Among these, when the eight light emitting / receiving sections 711 and 721 are distributed to a plurality of light emitting / receiving elements, as shown in FIG. Each arrangement can be freely set such that the light emitting elements are placed on the upper surface of the insulating substrate 11.

  On the other hand, when the eight light emitting / receiving units 711 and 721 are integrated into one light emitting / receiving element, it is not necessary to consider the mutual positional relationship between the plurality of light emitting / receiving elements. Can be placed accurately. As a result, variations in the transmission characteristics of the optical paths of the light emitting / receiving units 711 and 721 can be suppressed.

  The average thickness of the first wiring 15 and the second wiring 16 as described above is appropriately set according to the constituent materials of the wirings 15 and 16, the electrical resistance values required for the wirings 15 and 16, and the like. However, it is about 1 to 30 μm as an example.

  In addition, the width of the first wiring 15 and the width of the second wiring 16 are also appropriately set according to the constituent material of each wiring 15, 16 and the electrical resistance value required for each wiring 15, 16, As an example, the thickness is preferably about 2 to 1000 μm, and more preferably about 5 to 500 μm.

  Each of the wirings 15 and 16 is formed by, for example, a method of patterning a conductive layer once formed on the entire surface (for example, patterning a copper foil of a copper-clad substrate), or a conductive pattern previously patterned on a separately prepared substrate. It is formed by a method of transferring a layer.

  On the other hand, the through via structure 151 provided in each through hole 121 of the frame substrate 12 and the above-described through wiring 161 are formed, for example, by depositing a conductive film by various plating methods.

  Further, the connection terminal 152 provided in the opening of each through hole 121 may be the upper end surface of each through via structure 151, or may be a pad with a larger area connected to the upper end surface.

  Examples of conductive materials used for the first wiring 15, the second wiring 16, the connection terminal 152, the through via structure 151, and the through wiring 161 include aluminum (Al), copper (Cu), gold (Au), Various metal materials, such as silver (Ag), platinum (Pt), nickel (Ni), tungsten (W), molybdenum (Mo), are mentioned.

  The bumps 153 provided on the connection terminals 152 are ball-shaped or land-shaped electrodes made of various solders, various brazing materials, and the like.

  Among them, as solder or brazing material, Sn—Pb lead solder, Sn—Ag—Cu, Sn—Zn—Bi, Sn—Cu, Sn—Ag—In—Bi, Sn— Examples include various lead-free solders based on Zn-Al, various low-temperature brazing materials defined in JIS, and the like.

  The bumps 153 are electrodes that are responsible for connection when the opto-electric hybrid board 1 is electrically connected to other members. With the bump 153, the opto-electric hybrid board 1 can be mounted in a BGA (Ball Grid Array) type or an LGA (Land Grid Array) type.

  Further, when the connection terminal 152 comes into contact with the solder (or brazing material), there is a possibility that a part of the metal component constituting the connection terminal 152 is dissolved on the solder side. This phenomenon is called “copper erosion” because it often occurs particularly for copper terminals. When copper erosion occurs, there is a risk that the connection terminal 152 may be thinned or damaged, and the function of the connection terminal 152 may be impaired.

  Therefore, it is preferable to previously form a copper erosion prevention film (underlayer) as a solder underlayer on the surface of the connection terminal 152 in contact with the conductive material. By forming the copper erosion prevention film, copper erosion is prevented, and the function of the connection terminal 152 can be maintained for a long time.

  Examples of the constituent material of the copper corrosion prevention film include nickel (Ni), gold (Au), platinum (Pt), tin (Sn), palladium (Pd), and the like. A single layer composed of one kind of metal composition may be used, or a composite layer containing two or more kinds (for example, a Ni—Au composite layer, a Ni—Sn composite layer, etc.) may be used.

  The average thickness of the copper erosion preventing film is not particularly limited, but is preferably about 0.05 to 5 μm, and more preferably about 0.1 to 3 μm. Thereby, it is possible to exhibit a sufficient copper erosion preventing action while suppressing the electrical resistance of the copper erosion preventing film itself.

  As described above, the light emitting / receiving element 7 (light emitting / receiving element 71 and light emitting / receiving element 72) provided inside the frame-shaped substrate 12 has the light receiving / emitting portions 711, 721 and the electrode pads 721, 722 on the lower surface. Specifically, it is a light emitting element such as a surface emitting laser (VCSEL) or a light emitting diode (LED), or a light receiving element such as a photodiode (PD, APD).

  On the other hand, the semiconductor element 8 adjacent to the light emitting / receiving element 7 is an element that controls the operation of the light emitting / receiving element 7, and has an electrode pad 812 on the lower surface. Examples of the semiconductor element 8 include a combination IC including a driver IC, a transimpedance amplifier (TIA), a limiting amplifier (LA), and various LSIs and RAMs.

  In addition, the 1st wiring 15 is not limited to said structure, For example, it can substitute with a bonding wire etc.

  In addition, the electrical connection between the electrode pads 712 and 722 provided on the light emitting and receiving elements 71 and 72 and the wirings 15 and 16 is performed via a conductive material (not shown). In addition to the solder or brazing material described above, anisotropic conductive film (ACF) and anisotropic conductive paste (ACP) are used.

  Furthermore, when various bumps such as stud bumps are provided on the electrode pads 712 and 722, ultrasonic bonding (for example, Au-Au bonding, Cu-Cu bonding, Al-Al bonding, etc.), gold-solder bonding Can also be electrically connected.

  Further, in a space 13 defined by the upper surface of the insulating substrate 11 and the inner surface of the frame-shaped substrate 12, a mold resin (sealing resin) 14 is provided so as to cover at least the entire light emitting / receiving element 7 and the entire semiconductor element 8. Filled. The mold resin 14 reliably protects the light emitting / receiving element 7 and the semiconductor element 8 from weather resistance (heat resistance, moisture resistance, atmospheric pressure change, etc.), vibration, external force, stress concentration, foreign matter adhesion, and the like.

  The first wiring 15, the electrode pads 712 and 722 of the light emitting and receiving elements 71 and 72, and the electrode pad 812 of the semiconductor element 8 each have a predetermined thickness. There is a slight gap between the upper surface of the element and the elements 7 and 8. The mold resin 14 also enters the gap and fills the gap.

  In this case, since the mold resin 14 is also present on the optical path, it is preferable to have as high a translucency as possible. Further, in order to increase the translucency of the interface between the mold resin 14 and the insulating substrate 11, it is preferable that the mold resin 14 has a refractive index close to that of the insulating substrate 11. Specifically, the refractive index difference between the two is preferably 0.05 or less.

  Examples of the mold resin 14 include an epoxy resin, a polyester resin, a polyurethane resin, a silicone resin, and a norbornene resin.

  Further, in the optical element mounting substrate 10, the bottomed space 13 is filled with the mold resin 14, so that the filled mold resin 14 does not flow out of the space 13 even when uncured. For this reason, the viscosity of the mold resin 14 at the time of filling does not need to be particularly controlled, and the filling operation is easy.

  Note that an underfill agent may be filled in the gap between the light emitting / receiving element 7 and the insulating substrate 11, the gap between the semiconductor element 8 and the insulating substrate 11, or the gap and its periphery. As this underfill agent, a material having translucency is used, and specifically, a material mainly composed of an epoxy resin or a silicone resin is preferably used. Further, when an underfill agent is used, the mold resin 14 filled from above does not necessarily have translucency.

  The optical element mounting substrate 10 as described above has an advantage that the opto-electric hybrid board 1 having high optical signal transmission characteristics can be manufactured very simply by simply laminating its lower surface so as to be in contact with the optical circuit layer 2. Have

  In the optical element mounting substrate 10, even when a large number of light emitting / receiving portions 711 and 721 are arranged at high density, it is not necessary to reduce the line and space of the wirings 15 and 16. 165 has sufficient conductivity and insulation. As a result, the optical element mounting substrate 10 has high electrical signal transmission characteristics. For this reason, the opto-electric hybrid board 1 provided with such an optical element mounting board 10 has excellent performance in terms of electric signal transmission characteristics. Since each of the wirings 15 and 16 does not require high dimensional accuracy, there is an advantage that the manufacturing is easy.

  Such an optical element mounting substrate 10 may be stacked on one end of the optical circuit layer 2 or may be stacked on both ends.

  An opto-electric hybrid board 1 shown in FIG. 5A is formed by laminating optical element mounting boards 10 on both ends of the optical circuit layer 2. Further, mirrors 22 are respectively formed corresponding to the arrangement of the light emitting / receiving elements 7 of the optical element mounting substrate 10. Thereby, in the opto-electric hybrid board 1, an optical signal is generated from the electrical signal in one optical element mounting board 10, and the obtained optical signal is propagated to the other optical element mounting board 10 in the optical circuit layer 2. The other optical element mounting substrate 10 generates an electrical signal from the received optical signal. In this way, data communication using an optical signal can be performed between both ends.

  On the other hand, in the opto-electric hybrid board 1 shown in FIG. 5B, the optical element mounting substrate 10 is laminated on one end of the optical circuit layer 2, and the optical circuit layer 2 is placed on the other end. And a connector 20 for connecting to the connection partner. Examples of the connector 20 include a PMT connector used for connection with an optical fiber. That is, the connector 20 is connected to, for example, an optical fiber, so that the optical circuit layer 2 can be extended by the optical fiber. As a result, longer-distance optical communication is possible using the opto-electric hybrid board 1.

  Note that the opto-electric hybrid board 1 shown in FIG. 5 has a configuration on the premise that one end and the other end are connected in a one-to-one relationship. One-to-multiple connection is possible by interposing an optical splitter capable of branching. In this case, the optical element mounting substrate 10 may be laminated on all of the plurality of end portions, the optical element mounting substrate 10 may be partially laminated, and the rest may be provided with the connector 20. All of the connectors 20 may be provided.

<Method for manufacturing opto-electric hybrid board>
Next, an example of a method for manufacturing the opto-electric hybrid board 1 as described above will be described.

  The opto-electric hybrid board 1 shown in FIG. 1 is manufactured by preparing an optical circuit layer 2 and an optical element mounting board 10 and laminating them.

[1] Manufacture of Optical Element Mounting Substrate First, a manufacturing method of the optical element mounting substrate 10 used for manufacturing the opto-electric hybrid board 1 will be described.

[1-1] Manufacturing of Wiring etc. An insulating substrate 11 is prepared, and a conductive layer is formed so as to cover part or all of both surfaces.

  This conductive layer is a coating of the above-described metal composition, chemical vapor deposition methods such as plasma CVD, thermal CVD, and laser CVD, physical vapor deposition methods such as vacuum vapor deposition, sputtering, and ion plating, electrolytic plating, electroless plating, etc. The plating method, thermal spraying method, sol-gel method, MOD method and the like are used. In addition, when using the board | substrate which laminated copper foil beforehand as the insulating board | substrate 11 to prepare, formation of a conductive layer can be abbreviate | omitted.

  Next, this conductive layer is patterned by various patterning methods. Examples of the patterning method include a method in which a photolithography method and an etching method are combined.

  As described above, as shown in FIG. 6A, the first wiring 15 and the second wiring 16 are formed on both surfaces of the insulating substrate 11.

  In addition, the through hole 110 is formed in the insulating substrate 11 and the through wiring 161 is formed in the insulating substrate 11.

  Examples of the method for forming the through hole 110 include various processing methods such as a laser processing method, an electron beam processing method, and a machining method.

[1-2] Lamination of Frame-Shaped Substrate Next, as shown in FIG. 6A, a through via structure is formed on the insulating substrate 11 provided with the first wiring 15, the second wiring 16, and the through wiring 161. The frame-like substrate 12 provided with 151 and connection terminals 152 is laminated.

  The insulating substrate 11 and the frame-shaped substrate 12 are bonded by a method such as thermocompression bonding or bonding with various adhesives (including adhesive).

  Examples of the adhesive include epoxy adhesives, acrylic adhesives, urethane adhesives, silicone adhesives, and various hot melt adhesives (polyester and modified olefins). Moreover, as a thing with especially high heat resistance, thermoplastic polyimide adhesive agents, such as a polyimide, a polyimide amide, a polyimide amide ether, a polyester imide, a polyimide ether, are mentioned.

  Note that the first wiring 15 and the second wiring 16 and the through via structure 151 are electrically connected by this lamination.

[1-3] Mounting of Elements Next, as shown in FIG. 6B, the light emitting / receiving element 7 and the semiconductor element 8 are mounted inside the frame substrate 12. Accordingly, between the first wiring 15 and the electrode pad 712 of the light emitting / receiving element 71, between the second wiring 16 and the electrode pad 722 of the light emitting / receiving element 72, and between the wirings 15 and 16 and the semiconductor element 8. The electrode pads 812 are electrically connected to each other.

  Next, as shown in FIG. 6C, the mold resin 14 is supplied to the space 13 inside the frame-shaped substrate 12 and solidified. Thereby, the light emitting / receiving element 7 and the semiconductor element 8 provided in the space 13 are sealed with the mold resin 14.

Next, as illustrated in FIG. 6D, bumps 153 are provided on the connection terminals 152. Such a bump 153 is formed by a method of supplying solder or a solder melt or ball onto the connection terminal 152, a method of applying a solder paste (brazing material paste), and drying.
The optical element mounting substrate 10 is obtained as described above.

[2] Production of Optical Circuit Layer Next, the clad layer 211, the core layer 213, and the clad layer 212 are produced. After forming the liquid film by applying the composition for forming each layer on the base material, the base material is placed on a level table to level the uneven portion of the liquid film surface. Formed by evaporation (desolvation) of the solvent.

  Examples of the coating method for forming the liquid film include a doctor blade method, a spin coating method, a dipping method, a table coating method, a spray method, an applicator method, a curtain coating method, and a die coating method.

  In addition, as a method of forming the core part 214 and the side cladding part 215 in the same layer (core layer 213), for example, a photo bleaching method, a photolithography method, a direct exposure method, a nanoimprinting method, a monomer diffusion, and the like. Law.

  Thereafter, the formed cladding layer 211, core layer 213, and cladding layer 212 are pressure-bonded to each other. Thereby, the clad layer 211, the core layer 213, and the clad layer 212 are joined and integrated, and the optical circuit layer 2 (optical waveguide 21) is obtained.

[3] Manufacture of opto-electric hybrid board Next, a method of manufacturing the opto-electric hybrid board 1 using the optical element mounting board 10 will be described.

  First, the optical circuit layer 2 and the optical element mounting substrate 10 are sequentially laminated, and the layers are bonded. Thereby, the opto-electric hybrid board 1 shown in FIG.

  Each layer is bonded by a method such as thermocompression bonding or bonding with the above-described various adhesives (including adhesives). If the clad layer 212 has adhesiveness, the adhesiveness is increased. You may make it adhere | attach using.

(Second Embodiment)
Next, a second embodiment of the optical element mounting substrate of the present invention and a second embodiment of the opto-electric hybrid board of the present invention provided with this optical element mounting substrate will be described.

  FIG. 7 is a cross-sectional view schematically showing a second embodiment of the optical element mounting substrate and the opto-electric hybrid substrate according to the present invention. In the following description, the upper side in FIG. 7 is referred to as “upper” and the lower side is referred to as “lower”. In each drawing, the thickness direction of each substrate is emphasized.

  Hereinafter, the second embodiment of the optical element mounting substrate and the opto-electric hybrid board will be described, but the description will focus on differences from the first embodiment, and the description of the same matters will be omitted. In FIG. 7, components similar to those in the first embodiment are denoted by the same reference numerals as those in FIG. 2 described above, and detailed description thereof is omitted.

  The optical element mounting substrate 10 shown in FIG. 7 omits the through hole 110 provided in the insulating substrate 11 and has a plurality of through wirings 162 provided so as to penetrate the insulating substrate 11 instead. This is the same as in the first embodiment.

  That is, in the optical element mounting substrate 10 shown in FIG. 7, both the light receiving / emitting element 71 and the light receiving / emitting element 72 are mounted on the upper surface of the insulating substrate 11, and the electrode pad 722 of the light receiving / emitting element 72 is penetrated. It is electrically connected to the second wiring 16 through the wiring 162. In the opto-electric hybrid board 1 provided with such an optical element mounting board 10, as in the first embodiment, there is a margin in the space required for the wiring 15 and 16, and the same action and function as in the first embodiment are obtained. An effect is obtained.

  Further, in this embodiment, since it is not necessary to provide a through hole 110 large enough to insert the light emitting / receiving element 72 in the insulating substrate 11, the mechanical strength of the insulating substrate 11 due to the through hole 110 is prevented from being lowered. .

  The through wiring 162 is made of the same material as that of the above-described through wiring 161 and is formed by the same method.

(Third embodiment)
Next, a third embodiment of the opto-electric hybrid board according to the present invention will be described.

  FIG. 8 is a cross-sectional view schematically showing a third embodiment of the opto-electric hybrid board according to the present invention. In the following description, the upper side in FIG. 8 is referred to as “upper” and the lower side is referred to as “lower”. In each drawing, the thickness direction of each substrate is emphasized.

  Hereinafter, although the third embodiment of the opto-electric hybrid board will be described, the description will be focused on the differences from the first embodiment, and the description of the same matters will be omitted. In FIG. 8, the same components as those in the first embodiment are denoted by the same reference numerals as those in FIG. 2 described above, and detailed description thereof is omitted.

  The opto-electric hybrid board 1 shown in FIG. 8 is the same as the first embodiment except that the stacking direction of the optical element mounting board 10 and the optical circuit layer 2 is reversed left and right with respect to the first embodiment. .

  That is, in the first embodiment, as shown in FIG. 2, the optical waveguide 21 extends along an extension line extending in the direction from the light receiving / emitting element 71 to the light receiving / emitting element 72. 8, the optical element mounting substrate 10 and the optical circuit layer 2 are arranged so that the optical waveguide 21 extends along an extension line extending in the direction from the light emitting / receiving element 72 to the light receiving / emitting element 71. Are stacked.

  In such a configuration, the length of the optical path connecting the optical waveguide 21 and the light receiving / emitting element 72 is longer than the length of the optical path connecting the optical waveguide 21 and the light receiving / emitting element 71. Therefore, strictly speaking, the optical signal transmitted through the former optical path is delayed from the optical signal transmitted through the latter optical path in accordance with the difference in optical path length. In addition, the attenuation rate of the former optical path may increase by the length of the optical path.

  On the other hand, in this embodiment, since the light emitting / receiving element 72 having a long optical path length is provided in the through hole 110, the optical path length is shortened accordingly. Furthermore, since the light emitting / receiving element 72 is provided in the through hole 110, the optical path does not pass through the insulating substrate 11, and an increase in the attenuation factor of the optical path is prevented accordingly.

  For these reasons, the difference between the optical path length of the former and the optical path length of the latter is reduced, and the occurrence of delay between the optical paths and variations in the attenuation rate are prevented. For this reason, a more reliable opto-electric hybrid board 1 can be obtained.

  In addition to the above actions and effects, this embodiment can obtain the same actions and effects as the first embodiment.

(Fourth embodiment)
Next, a fourth embodiment of the optical element mounting substrate of the present invention and a fourth embodiment of the opto-electric hybrid substrate of the present invention will be described.

  FIG. 9 is a cross-sectional view schematically showing a fourth embodiment of the optical element mounting substrate and the opto-electric hybrid board according to the present invention. In the following description, the upper side in FIG. 9 is referred to as “upper” and the lower side is referred to as “lower”. In each drawing, the thickness direction of each substrate is emphasized.

  Hereinafter, the fourth embodiment of the optical element mounting substrate and the opto-electric hybrid board will be described. However, the difference from the first embodiment will be mainly described, and description of similar matters will be omitted. In FIG. 9, the same components as those in the first embodiment are denoted by the same reference numerals as those in FIG. 2 described above, and detailed description thereof is omitted.

  The optical element mounting substrate 10 shown in FIG. 9 is the same as that of the first embodiment except that two sets of light receiving / emitting elements 71, light receiving / emitting elements 72, and semiconductor elements 8 are mounted.

  That is, in the fourth embodiment, two light emitting / receiving elements 72 provided in parallel on the innermost side of the frame-shaped substrate 12, two light receiving / emitting elements 71 provided in parallel on the outer side, and on the outer side thereof. It has two semiconductor elements 8 provided. In such an optical element mounting substrate 10, although not shown, since the four light receiving / emitting portions 711 and 721 are arranged in four rows, optical connection to the 16-channel optical circuit layer 2 is possible. Become. For this reason, the opto-electric hybrid board 1 capable of higher density mounting is obtained.

  In addition to the above actions and effects, this embodiment can obtain the same actions and effects as the first embodiment.

(Fifth embodiment)
Next, a fifth embodiment of the optical element mounting substrate of the present invention and a fifth embodiment of the opto-electric hybrid substrate of the present invention will be described.

  FIG. 10A is a plan view and FIG. 10B is a cross-sectional view schematically showing a fifth embodiment of the optical element mounting substrate and the opto-electric hybrid board according to the present invention. In the following description, the upper side in FIG. 10B is referred to as “upper” and the lower side is referred to as “lower”. In each drawing, the thickness direction of each substrate is emphasized.

  Hereinafter, the fifth embodiment of the optical element mounting substrate and the opto-electric hybrid board will be described, but the description will focus on differences from the first embodiment, and the description of the same matters will be omitted. In FIG. 10, the same components as those in the first embodiment are denoted by the same reference numerals as those in FIG. 2 described above, and detailed description thereof is omitted.

  The optical element mounting substrate 10 shown in FIG. 10A omits the frame-shaped substrate 12 and has eight connector pads provided on the insulating substrate 11 as external terminals connected to the wirings 15 and 16. Except for using 154, it is the same as in the first embodiment.

  These connector pads 154 are electrically connected to an external circuit by being connected to a separately prepared connector.

  Each connector pad 154 is connected to the semiconductor element 8 via a wiring 155 disposed on the insulating substrate 11. Thereby, each connector pad 154 functions as an external electrode of the opto-electric hybrid board 1.

  The insulating substrate 11 extends rightward beyond the right end of the optical circuit layer 2 laminated on the lower surface. Each of the connector pads 154 described above is provided on the upper surface of the extended portion. On the other hand, a support substrate 17 is laminated on the lower surface of the extended portion. Since the extended portion is reinforced by the support substrate 17, it is possible to prevent the extended portion from being bent or damaged by the applied external force when the opto-electric hybrid board 1 is connected to the connector.

  Each connector pad 154 and the wiring 155 are made of the same material as the first wiring 15 and the second wiring 16 described above, and are formed by the same method.

  The support substrate 17 is made of the same material as that of the frame-shaped substrate 12 described above and has the same thickness.

  In addition, although the present embodiment has a slightly different structure, the same operation and effect as the first embodiment can be obtained.

<Electronic equipment>
The electronic device including the opto-electric hybrid board of the present invention (the electronic device of the present invention) can be applied to any electronic device that performs signal processing of both an optical signal and an electric signal. For example, a router device, a WDM device, etc. Application to electronic devices such as mobile phones, game machines, personal computers, televisions, home servers, etc. is preferable. In any of these electronic devices, it is necessary to transmit a large amount of data at high speed between an arithmetic device such as an LSI and a storage device such as a RAM. Therefore, by providing such an electronic device with the opto-electric hybrid board according to the present invention, problems such as noise and signal deterioration peculiar to the electric wiring are eliminated, and a dramatic improvement in the performance can be expected.

  In addition, the amount of heat generated in the optical waveguide portion is greatly reduced compared to electrical wiring. Therefore, the degree of integration in the substrate can be increased to reduce the size, the power required for cooling can be reduced, and the power consumption of the entire electronic device can be reduced.

  The embodiments of the optical element mounting substrate, the opto-electric hybrid board, and the electronic device according to the present invention have been described above. However, the present invention is not limited to this, and for example, the optical element mounting board and the opto-electric hybrid board are configured. Each part to be replaced can be replaced with one having any configuration capable of performing the same function. Moreover, arbitrary components may be added.

  For example, a cover film may be laminated on each of the upper surface and the lower surface of the optical circuit layer 2. The cover film can reliably protect the optical circuit layer 2. In addition, as a cover film, the thing similar to the insulating board | substrate 11 is used.

DESCRIPTION OF SYMBOLS 1 Opto-electric hybrid board 10 Optical element mounting board 110 Through-hole 11 Insulating board 12 Frame-like board 121 Through-hole 13 Space 14 Mold resin 15 First wiring 151 Through-via structure 152 Connection terminal 153 Bump 154 Connector pad 155 Wiring 16 Second wiring 161, 162 Through wiring 17 Support substrate 2 Optical circuit layer 20 Connector 21 Optical waveguide 211, 212 Clad layer 213 Core layer 214 Core part 215 Side clad part 22 Mirror 7, 71, 72 Light emitting / receiving element 711, 721 Light emitting portion 712, 722 Electrode pad 8 Semiconductor element 812 Electrode pad 9 Opto-electric hybrid board 90 Optical element mounting board 91 Insulating board 951, 952 Wiring L interval

Claims (16)

An insulating substrate;
A plurality of light emitting / receiving sections that receive or emit light;
A first wiring provided on a first surface of the insulating substrate;
A second wiring provided on a second surface opposite to the first surface of the insulating substrate;
An optical element mounting substrate that is used to optically connect the plurality of light emitting / receiving portions and the plurality of channels by being laminated with an optical waveguide having a plurality of channels on the second surface side. There,
The plurality of light emitting / receiving units are arranged in two or more parallel rows in a plan view, and the light receiving / emitting units included in the first column that is one of the columns are the first wiring And the light emitting / receiving section included in the second column different from the first column is electrically connected to the second wiring. Mounting board. The insulating substrate has a through hole,
The optical element mounting substrate according to claim 1, wherein the light receiving and emitting units included in the second row are provided in the through hole. The second wiring has an extended portion extending in the vicinity of the opening of the through hole,
The optical element mounting substrate according to claim 2, wherein in the extended portion, the light receiving and emitting units included in the second row and the second wiring are electrically connected. The insulating substrate has a through hole and a through wiring provided in the through hole,
The light emitting / receiving units included in the second row are provided on the first surface side of the insulating substrate,
The optical element mounting substrate according to claim 1, wherein the light receiving and emitting units included in the second row and the second wiring are electrically connected through the through wiring.   5. The optical element mounting substrate according to claim 1, wherein the first wiring and the second wiring each extend in the same direction. 6.   The optical element mounting substrate according to claim 1, wherein projected images of the first wiring and the second wiring on the same plane parallel to the insulating substrate overlap at least partially.   The optical element mounting substrate according to claim 1, wherein the plurality of light emitting / receiving units are all mounted on one optical element.   The optical element mounting substrate according to claim 1, wherein the plurality of light receiving and emitting units are distributed and mounted on a plurality of optical elements.   The optical element mounting substrate according to claim 7, further comprising a frame-shaped substrate provided on the first surface side and configured to surround the entire circumference of the optical element.   The optical element mounting substrate according to claim 9, wherein a thickness of the frame-shaped substrate is thicker than a thickness of the optical element.   The optical element mounting substrate according to claim 1, wherein an average thickness of the insulating substrate is 5 to 50 μm. A control element that is provided on the first surface side of the insulating substrate and controls operations of the plurality of light emitting and receiving units;
Each of the first wiring and the second wiring is provided to connect the plurality of light emitting / receiving units and the control element,
The optical element mounting according to any one of claims 1 to 11, wherein an arrangement surface of the second wiring is changed from the second surface to the first surface in the middle of the second wiring. substrate. An optical element mounting substrate according to any one of claims 1 to 12,
An optical waveguide comprising a plurality of channels and provided on the second surface side of the insulating substrate;
An opto-electric hybrid board comprising optical path changing means for optically connecting the plurality of light emitting / receiving sections and the plurality of channels.   The opto-electric hybrid board according to claim 13, wherein the optical element mounting board is laminated on one end part or both end parts of the optical waveguide. The optical element mounting substrate is provided at one end of the optical waveguide,
The opto-electric hybrid board according to claim 13, further comprising a connector provided at the other end of the optical waveguide and connecting the optical waveguide to a connection partner.   An electronic apparatus comprising the opto-electric hybrid board according to claim 13.

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