JP4624162B2 - Opto-electric wiring board - Google Patents

Description

  In the present invention, an electrical wiring and an optical waveguide are formed on a substrate, and a light emitting element and a light receiving element disposed thereon can be optically and easily optically coupled through the optical waveguide, The present invention relates to a photoelectric wiring board that can be electrically connected.

  2. Description of the Related Art In recent years, with the improvement of computer processing capability, in an electrical element such as a semiconductor large scale integrated circuit (LSI) used as a microprocessor, the degree of integration of transistors has been increased, and the operation speed has reached GHz in terms of clock frequency. Along with this, the electrical wiring for electrically connecting the electrical elements has been increasing in density and miniaturization.

  The miniaturization of electrical wiring accompanying the increase in the speed of microprocessors increases crosstalk and propagation loss. This causes problems such as limitations in high density and complicated driving and receiving circuits. This is an obstacle to the high performance of computers.

  On the other hand, as a technique for solving these problems, a part of the electrical wiring by the wiring conductor made of copper on the conventional printed wiring board is replaced with the optical wiring by the optical fiber or the optical waveguide, and the wiring between the elements is electrically connected. An optical wiring is used instead of the wiring. The optical wiring is non-inductive, and the core part that becomes the signal line has a cross-section size of about 50 μm □ even in multimode. Talk can be reduced and wiring can be miniaturized and densified.

  However, when an optical fiber is used as an optical wiring, its flexibility is limited, so that it cannot cope with an optical wiring with a complicated shape, and the degree of freedom in wiring design is reduced, resulting in a high density wiring. In addition, there is a problem that it cannot sufficiently cope with downsizing of the substrate. Therefore, a configuration using an optical waveguide having a high degree of design freedom is effective as the optical wiring.

  An optical waveguide is composed of a core part that becomes a signal line through which an optical signal propagates, and a clad part that is arranged around the core part and traps the optical signal in the core part, and is formed in a direction parallel to the surface of the substrate. ing. There are several methods for forming the core, such as dry etching using photolithography technology and exposure and development using a photosensitive core material. In any case, the shape and dimensional accuracy are determined by the photomask pattern. The degree of freedom increases.

  When mounting optical and electrical components such as semiconductor light emitting devices on an optical waveguide substrate using such an optical waveguide for optical wiring, it can be mounted using surface mounting technology used for conventional electrical components. desirable. For this reason, surface-emitting vertical cavity surface emitting lasers (VCSELs) and surface-receiving semiconductor light-receiving devices (PDs: Photo Diodes), which are advantageous for power saving and surface array, are used as optical components. Is used.

  In order to optically couple an optical waveguide formed in a direction parallel to the surface of the substrate and an optical component such as a VCSEL or PD mounted on the surface of the substrate, an optical waveguide using an optical path changing means such as a mirror is used. It is necessary to bend the optical path by approximately 90 degrees from the direction parallel to the surface of the substrate to the direction perpendicular to the surface of the substrate. Several proposals have been made for the method of forming the optical path changing means.

  For example, there is a method of forming a slope serving as a mirror surface on the surface of the substrate by dry etching. In this method, the substrate is tilted to perform dry etching, or a photoresist pattern having a slope is formed using a gray scale photomask, and then dry etching is performed to form a mirror surface on the surface of the substrate. Form a slope.

  As another slope forming method, there is a method using a dicing saw for semiconductor chip separation. This is because an optical waveguide composed of a lower clad layer / core part / upper clad layer is formed, and then a dicing saw whose tip is processed at 45 degrees or 90 degrees is used to form an optical input / output section with respect to the optical waveguide. Cutting is performed to form a 45 ° end face on the optical waveguide, and a metal thin film is deposited on the exposed 45 ° end face to form a mirror surface (light reflecting surface).

In addition, there are a method of forming each inclined surface that becomes a mirror surface on the surface of the substrate using a laser or the like, and a method of separately preparing and arranging a member that becomes a mirror.
Japanese Patent Laid-Open No. 2003-50329

  However, these methods for forming optical path conversion means have various problems as described below.

  First, in the method of forming the inclined surface that becomes the mirror surface by dry etching, the method of performing the dry etching by tilting the substrate tends to cause variations in the accuracy of the inclined surface within the surface of the substrate, and a photoresist pattern having an inclined surface is formed. The method of forming the slope using the method has a problem that it is difficult to finely control the inclination angle and thickness of the end face of the photoresist pattern.

  On the other hand, the method of forming a mirror surface using a dicing saw limits the place where the mirror can be placed on the surface of the substrate and causes the cutting surface to become a mirror surface to be rough. There was a problem. In addition, when mirror processing is performed using a laser or the like after the optical waveguide is formed, it is necessary to adjust and process each mirror forming portion, which requires a lot of labor and time. It was.

  Further, in the above-described method using a member that becomes a mirror, the mirror member is embedded between the substrate and the optical waveguide, and optical components such as a light emitting element and a light receiving element are mounted on the optical waveguide. Therefore, when the optical waveguide is formed of a polymer material resin that can be easily manufactured at low cost, the optical waveguide is easily affected by irregularities on the surface of the substrate, and irregularities are likely to occur on the upper surface of the optical waveguide. There was a problem that it was difficult to mount stable optical components. In addition, since the resin of the polymer material is soft, the mounting of the optical element on the upper surface of the optical waveguide may become unstable, and the electrical wiring on the resin may cause a problem in adhesion.

  The present invention has been devised to solve the above-described problems in the prior art, and an object thereof is to enable efficient optical coupling between an optical waveguide, a light emitting element, and a light receiving element by a simple method. At the same time, it is an object of the present invention to provide an optoelectric wiring board that enables simple and stable electrical connection between the light emitting element and the light receiving element. Another object of the present invention is to provide an optoelectric wiring board that can simplify the manufacturing process for optical coupling between the optical waveguide, the light emitting element, and the light receiving element, and is easy to manufacture and excellent in mass productivity. There is to do.

A first optoelectric wiring board according to the present invention includes a substrate, a first mirror member disposed on the substrate and formed of a conductive material and having a first mirror surface on a side surface, and the substrate A second mirror member having a second mirror surface disposed on the side surface and opposite to the first mirror surface on a side surface; and the first and second mirror surfaces It is disposed between, viewed including the clad portion surrounding the core portion and the core portion, the optical waveguide is configured to optically coupled to the mirror surface of the first and second, the first and second mirror member An electrical wiring that is electrically connected, a light emitting portion is positioned above the first mirror surface , optically coupled to the optical waveguide , and on the upper surface of the first mirror member the light emitting element is electrically connected, the said electric wiring via the first mirror member An optical device electrically connected to said positions the light receiving portion above the second mirror surface optically coupled to said optical waveguide, and electrically the light-receiving element on an upper surface of the second mirror member connect, connects the light receiving element to the electric wiring via the second mirror member.
The second optoelectric wiring board of the present invention surrounds a substrate, a mirror member disposed on the substrate and made of a conductive material and having a mirror surface on a side surface, the core portion, and the core portion. An optical waveguide including a clad portion and configured to be optically coupled to the mirror surface; and an electrical wiring electrically connected to the mirror member; and a light emitting portion above the mirror surface. position is not optically coupled to said optical waveguide, or and wherein electrically connecting the light emitting element on the upper surface of the mirror member, connecting the light emitting element to the electrical wiring through the mirror member, or, optically coupled to said optical waveguide to position the light receiving portion above the mirror surface, electrically connected and the light receiving element on an upper surface of the mirror member, the said electrical wiring through the mirror member Connect the light receiving element.

  According to the optoelectric wiring board of the present invention, on the substrate, two mirror members disposed with their mirror surfaces facing each other, a core portion disposed between the mirror surfaces, and a clad portion surrounding the core portion A light-emitting element is disposed on one of the mirror surfaces, and a light-receiving element is disposed on the other of the mirror surfaces, and the mirror member is electrically conductive. The mirror surface that is electrically connected to the electrical wiring and whose side surface converts the light propagation direction between a direction parallel to the surface of the substrate and a direction perpendicular to the surface of the substrate. Since the terminal electrode of the light emitting element or the light receiving element is connected with the light emitting part or the light receiving part positioned on the mirror surface, the optical path changing means by the mirror surface on the side surface by disposing the mirror member on the substrate Get At the same time, by connecting the terminal electrode of the light emitting element or the light receiving element to the upper surface of the mirror member made of a conductive material and electrically connected to the electrical wiring, with the light emitting part or the light receiving part positioned on the mirror surface In addition to the optical path conversion between the light guide and the light emitting part or the light receiving part, it is possible to connect the light emitting element and the light receiving element to the electric wiring on the substrate, so that the mirror surface with respect to the surface of the substrate as in the prior art The electrical wiring formed on the substrate and the electrical wiring formed on the optical waveguide and connected to the terminal electrode of the light emitting element or the light receiving element are electrically connected. Since there is no need to separately form through conductors such as via conductors for connection, it is advantageous in increasing the density of optical wiring and electrical wiring, and can be easily manufactured, and has an optoelectric coupling structure with excellent mass productivity. It is possible to obtain electrical wiring board.

  In particular, when the mirror member is made of metal among conductive materials, for example, the reflectivity of gold, silver, and copper having a good reflection surface for light with a wavelength of 850 nm is as high as about 98%. Therefore, since light can be efficiently reflected by the metal mirror surface formed on the side surface, high coupling efficiency can be obtained in optical path conversion between the optical waveguide, the light emitting element, and the light receiving element.

  In addition, when impedance matching of 50Ω is taken for the electrical wiring on the substrate in order to achieve impedance matching of the electrical wiring, it will be 50Ω depending on the size (total volume) of the mirror member and the resistivity of the material. It is also possible to design the mirror member to have a terminal resistance of 50Ω, for example, and in that case, it is not necessary to form a separate resistor on the electrical wiring, so an electrical wiring that can achieve impedance matching is provided. The number of manufacturing steps for formation can be reduced, and a substrate corresponding to high-speed signal can be easily obtained.

  In addition, the light emitting element and the light receiving element can obtain high-efficiency optical coupling with the optical waveguide via the mirror surface of the mirror member by a general surface mounting technique, and the light emitting part and the light receiving part are mirrored respectively. Since it is arranged on the mirror surface of the member, it can be used as a base on the mirror surface that is hard and stable compared to the resin that is the optical waveguide material. It is less affected by the thickness of solder, etc., or pressure during mounting, and can stably mount the light emitting element and the light receiving element. The mounting strength is high and the reliability is high. Since formation can be minimized, an optoelectric wiring board that can be easily miniaturized and can be mounted at high density can be obtained.

  As described above, according to the optoelectric wiring board of the present invention, the optical waveguide on the substrate, the light emitting element, and the light receiving element can be efficiently optically coupled through the mirror surface of the mirror member, and the light emitting element and the light receiving element can be coupled. The electrical connection between the element and the electric wiring on the substrate can be easily performed via the mirror member, and the manufacturing process can be reduced, and the photoelectric wiring substrate can be manufactured easily and at low cost and with high reliability. Can be provided.

  That is, according to the optoelectric wiring board of the present invention, the mirror surface of the mirror member is not limited by the place where the light input / output unit is arranged unlike the dicing process of the light reflecting surface in the conventional optoelectric wiring board. The optical waveguide and the light emitting element and the light receiving element can be optically coupled with high efficiency and easily, and at the same time, the electrical connection between the terminal electrode of the light emitting element and the light receiving element and the electric wiring of the substrate is also possible via the mirror member. Therefore, the cost required for the production / mounting process can be greatly reduced as compared with the conventional case without taking much time and labor for processing and mounting.

  Next, the optoelectric wiring board of the present invention will be described with reference to the drawings. FIG. 1 is a top view showing an example of an embodiment of an optoelectric wiring board according to the present invention, and FIG. 2 is a cross-sectional view taken along the line A-A 'of FIG.

  As shown in FIG. 1 and FIG. 2, the optoelectric wiring board 1 of the present invention has two mirror members 3 arranged on a substrate 2 with mirror surfaces 10 facing each other and facing each other. An optical waveguide 6 composed of a core portion 4 and a clad portion 5 surrounding the core portion 4 disposed between the mirror surfaces 10 is provided, and the light emitting element 7 is mounted on one of the mirror surfaces 10 with the mirror surface The light receiving element 8 is arranged on the other of the ten.

  As the substrate 2, for example, a printed wiring board made of an epoxy resin or the like generally used as a printed wiring board may be used. The substrate 2 has electrical wiring (not shown) on its upper surface and inside as needed. The electrical wiring may be formed not only on the upper surface of the substrate 2 but also inside the substrate 2 using a multilayer substrate in which electrical wiring layers and insulating layers are alternately laminated as the substrate 2. Of course, the substrate 2 is not limited to a printed wiring board, and may be a ceramic wiring board using alumina or the like as an insulating layer, or a board in which electric wiring is formed on silicon or glass. Among these, a glass epoxy wiring board is suitable as a versatile one that can be manufactured at low cost.

  The two mirror members 3 arranged on the substrate 2 with the mirror surfaces 10 facing each other are for converting the propagation direction of the optical signal between the direction parallel to the surface of the substrate 2 and the direction perpendicular to the surface of the substrate 2. An upper surface that has a mirror surface 10 that is an inclined surface and is a flat surface for connecting a terminal electrode (not shown) of the light emitting element 7 or the light receiving element 8 with the light emitting part or the light receiving part positioned on the mirror surface 10 11 and is formed at a height from the upper surface of the substrate 2 to the upper surface of the optical waveguide 6. The mirror member 3 is made of a conductive material, and is electrically connected to an electrical wiring formed on the substrate 2 or an electrical wiring 9 formed on an optical waveguide 6 described later.

  The mirror surface 10 on the side surface of the mirror member 3 is such that the propagation direction of the optical signal is parallel to the surface of the substrate 2 (the arrangement direction of the optical waveguide 6 formed on the substrate 2) and perpendicular to the surface of the substrate 2. In order to convert between directions (directions from the surface of the substrate 2 toward the light emitting part of the light emitting element 7 or the light receiving part of the light receiving element 8), an inclined surface of approximately 45 degrees is usually formed. By adjusting the inclination angle of the mirror surface 10, the light reflection direction can be adjusted. By adjusting the tilt angle of the mirror surface 10 according to the position of the light emitting part of the light emitting element 7 and the light receiving part of the light receiving element 8, the optical coupling efficiency at the time of mounting caused by the difference in the structure of the light emitting element 7 and the light receiving element 8 can be obtained. The difference can be minimized.

  In the example shown in FIG. 2, the cross-sectional shape of the inclined surface of the mirror surface 10 is indicated by a straight line (flat surface). However, the cross-sectional shape of the mirror surface 10 is not limited to a straight line (flat surface). It may have an arc shape such as a convex shape (a curved surface such as a concave surface or a convex surface).

  The cross-sectional shape of the mirror member 3 includes a mirror surface 10 which is an inclined surface for optical path conversion and an upper surface 11 which is a flat surface for disposing the light emitting element 7 or the light receiving element 8. As shown in FIG. 2, it is generally trapezoidal. The side surface on the opposite side of the mirror surface 10 does not necessarily have an inclined surface similar to that of the mirror surface 10 as shown in the figure, but the side surface on the opposite side is formed by having a substantially trapezoidal cross-sectional shape in this way. Can also be used as a mirror surface, so that the optical waveguide 6, the light emitting element 7 and the light receiving element 8 can be mounted on one substrate 2 with higher density, and the mirror surface can be formed by isotropic wet etching. In the case of forming 10, the mirror member 3 is easier to manufacture if it is symmetrical as shown. If the side surface opposite to the mirror surface 10 is a surface substantially perpendicular to the upper surface of the substrate 2, the area of the flat upper surface 11 of the mirror member 3 exposed on the upper surface of the optical waveguide 6 can be increased. Thus, it is possible to stabilize the mounting of the light emitting element 7 and the light receiving element 8 and the like and to improve the adhesion of the electrical wiring 9 on the upper surface of the optical waveguide 6.

  The mirror member 3 is made of a conductive material, and a metal such as Au, Pt, Hg, Cu, or Al, an alloy such as TaN used as a resistor, a conductive resin, or the like is used. For example, if the printed circuit board is used for the substrate 2 and is formed simultaneously with the copper plating of the electrical wiring thereon, Cu is used as the material of the mirror member 3, and the electrical wiring is performed using a normal plating process. Since it can be produced at the same time, it can be produced easily and at low cost. Of course, the formation of the mirror member 3 is not limited to the plating process. For example, a resist pattern having a reverse taper shape is formed on the upper surface of the substrate 2, and a conductive paste or the like is poured into the pattern to form a reverse taper shape. The mirror member 3 having the mirror surface 10 corresponding to the inclined surface can also be formed.

  The mirror surface 10 is disposed so as to face the end surface of the core portion 4 of the optical waveguide 6, and is inclined by 45 degrees with respect to the upper surface of the substrate 2 as shown in FIG. The light emitted from the light emitting part of the light source is converted to an optical path of approximately 90 degrees so as to be parallel to the upper surface of the substrate 2, and the upper surface of the substrate 2 from the end face of the core part 4. The light emitted parallel to the light is converted into an optical path of approximately 90 degrees so as to be perpendicular to the upper surface of the substrate 2 and guided to the light receiving portion of the light receiving element 8. If the distance between the mirror surface 10 and the end face of the core part 4 is long, light is diffused between them, and the light entering the core part 4 is reduced, and the light received by the light receiving element 8 is also reduced. Therefore, it is preferable that the distance between the mirror surface 10 and the end face of the core portion 4 is short. However, if the distance is too short, the shape of the core portion 4 may be deformed by the mirror member 3 and the optical path may be distorted. Therefore, the length of the core portion 4 is such that the end face of the core portion 4 is the end surface of the mirror member 3. Most preferably, it is at a position corresponding to the end portion of the bottom surface (the end surface of the core portion 4 is positioned above the end portion of the bottom surface of the mirror member 3).

  Further, the light emitting element 7 and the light receiving element 8 are arranged so that the perpendicular to the upper surface of the substrate 2 passing through the centers of the light emitting part and the light receiving part is located on the mirror member 3 so as to coincide with the center line of the core part 4. By providing, the coupling efficiency can be maximized.

  When the light emitting element 7, the light receiving element 8, and the optical waveguide 6 are arrayed in order to process more information, it corresponds to the array pitch (arrangement interval) on the light emitting element 7 and light receiving element 8 side. It is preferable that the core portions 4 of the optical waveguide 6 are also arrayed so that the cross-sectional shape of the plurality of core portions 4 arranged is always as shown in FIG. In this case, the mirror member 3 can be dealt with by forming a trapezoidal shape elongated in a direction perpendicular to the paper surface of FIG.

  The upper surface 11 of the mirror member 3 may be formed as a flat surface at the same time when the mirror member 3 is formed, or when the upper surface becomes a convex surface or a concave surface by using a conductive paste or the like as described above. The upper surface 11 as a flat surface can also be formed by polishing the upper surface simultaneously with the upper surface of the cladding portion 5 of the optical waveguide 6 after the optical waveguide 6 is formed. Further, when the mirror member 3 is formed, a conductive film is formed by a whole surface plating method, vapor deposition method, sputtering method, CVD method or the like, and then etched using a gray mask or the like, thereby flattening the mirror surface 10 which is an inclined surface. It is also possible to form the upper surface 11 which is a surface at the same time. Alternatively, the mirror member 3 can be formed on the substrate 2 by separately preparing the mirror member 3 by die-cutting or the like, and then bonding them to the upper surface of the substrate 2 and bonding them. In this case, since the lower part of the mirror member 3 is electrically connected by bonding to the electric wiring on the substrate 2, metal bonding, solder bonding, or bonding with a conductive adhesive can be used for bonding.

  After the mirror member 3 is formed on the substrate 2, the optical waveguide 6 is formed so as to be disposed between the mirror surfaces 10 facing the mirror member 3. As a material of the core part 4 which comprises the optical waveguide 6, and the clad part 5 surrounding the core part 4, for example, polysilane, acrylic, polyimide, epoxy, siloxane, polysilane, benzocyclobutene (BCB), methyl methacrylate (PMMA), A polymer material such as polycarbonate (PC) can be preferably used. In order to use a quartz-based material, it is necessary to produce the optical waveguide 6 by a process such as a flame deposition method or a CVD method. However, these are processes performed at a high temperature. Since a substrate using an organic material having low heat resistance cannot be used and a vacuum apparatus is required for manufacturing the optical waveguide 6, there is a problem that it is difficult to increase the area and the manufacturing cost is high. In contrast, the above-described polymer material can be formed on various substrates 2 because the optical waveguide 6 can be manufactured by a low-temperature process, can easily cope with a large area, and can be manufactured at low cost. It is preferable in that it can be performed. By using the above-mentioned polymer material for the core part 4 and the clad part 5, the optical waveguide 6 can be manufactured by a low temperature process, and it is easy to cope with an increase in area and can be manufactured at low cost. It will be a thing.

  For example, in the case of considering a multi-mode optical waveguide, the core portion 4 and the clad portion 5 have a thickness of about 40 μm and a thickness of the lower clad portion and the upper clad portion. The optical waveguide 6 having a thickness of about 100 μm may be used as 30 μm.

  As the optical waveguide 6, there are a reactive ion etching method, a direct exposure method, a refractive index change method (photo bleaching method) and the like as a method for producing the core portion 4 having a predetermined shape and size in the clad portion 5. Any method can be used, but the simplest manufacturing method is a refractive index change method. In the refractive index change method, since the refractive index is lowered by UV (ultraviolet) irradiation, the characteristics of the polysilane-based polymer material and the like are used. Therefore, the optical waveguide 6 can be simply formed without requiring a photolithography process such as development or etching. Can be produced.

  After the optical waveguide 6 is formed, in the optoelectric wiring board 1 of the present invention, since the optical waveguide 6 is formed on the substrate 2 having unevenness like the mirror member 3, the upper surface of the optical waveguide 6 is flattened. Therefore, it is preferable to perform light polishing. By this polishing, the upper surface of the optical waveguide 6 may be flattened, and the upper surface 11 of the mirror member 3 covered with the cladding portion 5 of the optical waveguide 6 may be exposed from the cladding portion 5 as a flat surface.

  Next, the electric wiring 9 is formed on the optical waveguide 6 including the upper surface 11 on the mirror member 3. The electrical wiring 9 may be a single layer film such as Au, Al, or Cu, or a laminated film such as Ti / Au, Ni / Au, or Cr / Au. The electrical wiring 9 can be formed by a plating method generally used in the manufacturing process of a printed wiring board, or can be formed by vapor deposition or sputtering and patterned by lift-off or etching. .

  When the electric wiring 9 is formed on the optical waveguide 6 as shown in FIGS. 1 and 2, the light emitting element 7 and the light receiving element 8 are usually formed with a signal pad and a ground pad. Therefore, for example, when the electrical wiring 9 that is electrically connected to the upper surface 11 of the mirror member 3 is used for grounding, the signal electrical wiring is provided on the optical waveguide 6 that is not electrically connected to the upper surface 11. 9 must be provided. On the contrary, when an optical signal is transmitted to the light emitting element 7 and the light receiving element 8 through the mirror member 3 using wiring (not shown) formed on the upper surface or inside of the substrate 2, it is used for the ground. It is necessary to provide the electrical wiring 9 on the optical waveguide 6.

  The terminal electrode of the light emitting element 7 and the light receiving element 8 is arranged on the upper surface 11 with the light emitting part or the light receiving part positioned on the mirror surface 10 on the photoelectric wiring board 1 of the present invention manufactured as described above. The light emitting element 7 and the light receiving element 8 are mounted in such a manner that the terminal electrodes are electrically connected to the electric wiring 9 electrically connected to the mirror member 3. Accordingly, the terminal electrodes of the light emitting element 7 and the light receiving element 8 are mounted on the upper surface 11 of the mirror member 3 which is harder than the optical waveguide 6, so that the light emitting element 7 and the light receiving element 8 can be stably mounted. And a highly reliable optoelectric wiring board 1 can be obtained.

  As described above, according to the optoelectric wiring board 1 of the present invention, between the mirror surface 10 and the two mirror members 3 disposed on the substrate 2 having the electric wiring 9 with the mirror surfaces 10 facing each other. An optical waveguide 6 comprising a core portion 4 and a clad portion 5 surrounding the core portion 4, a light emitting element 7 is disposed on one of the mirror surfaces 10, and the other of the mirror surfaces 10 The mirror member 3 is made of a conductive material and is electrically connected to the electrical wiring 9, and the side surface is parallel to the surface of the substrate 2 in the light propagation direction. A mirror surface 10 that converts between a normal direction and a vertical direction, and a terminal electrode of the light emitting element 7 or the light receiving element 8 is connected to the upper surface 11 with the light emitting part or the light receiving part positioned on the mirror surface 10 Therefore, the mirror member 3 is disposed on the substrate 2 to An optical path changing means between the optical waveguide 6 and the light emitting element 7 and the light receiving element 8 is obtained by the mirror surface 10 on the side, and at the same time, the electric wiring of the light emitting element 7 and the light receiving element 8 and the substrate 2 by the upper surface 11 of the mirror member 3. 9 can be electrically connected through the mirror member 3. Therefore, it does not require difficult processing such as processing of the mirror surface on the substrate in the conventional opto-electric wiring board, and the conductive protrusion for electrical connection between the light emitting element and the light receiving element and the electric wiring Since it is not necessary to separately form a portion or the like, the light emitting element 7 and the light receiving element 8 can be mounted with high reliability, and can be easily manufactured, and an optoelectric coupling structure excellent in mass productivity can be obtained. Become.

  Next, specific examples of the optoelectric wiring board according to the present invention will be described with reference to FIGS.

  3 (1) to 3 (6) are cross-sectional views for each process showing an example of a manufacturing process of the photoelectric wiring board of the present invention.

  First, an epoxy resin substrate having a thickness of 0.6 μm on which electric wiring (not shown) is formed was used as the substrate 2. A resist pattern having a through hole having a reverse taper-shaped cross section of about 45 degrees is formed on the substrate 2 using a negative photoresist, and the inside of the through hole is filled with Cu by electrolytic plating. The mirror member 3 made of was formed, and the photoresist was removed. As a result, as shown in FIG. 3A, the two mirror members 3 having the flat upper surface 11 are arranged on the substrate 2 with the mirror surfaces 10 facing each other. At this time, the height of the mirror member 3 was set to 100 μm.

  Next, an optical waveguide was formed between the opposing mirror surfaces 10 of the two mirror members 3. For the formation of the optical waveguide, a refractive index change method using a characteristic of the polysilane polymer material that the refractive index is lowered by UV (ultraviolet) irradiation was used.

  First, as shown in FIG. 3 (2), polysilane constituting the clad portion is applied on the substrate 2 on which the mirror member 3 is formed by spin coating so as to have a film thickness of about 33 μm. Time baking was performed to form the lower clad layer 20. The thickness of the lower cladding layer 20 after baking was 30 μm.

Next, as shown in FIG. 3 (3), polysilane having a high refractive index to be the core 4 and the side cladding layer 22 is applied on the lower cladding layer 20 by spin coating so as to have a film thickness of about 44 μm. Pre-baked at 130 degrees for 30 minutes. Thereafter, the core width is set to 40 μm, the photomask 21 in which the UV light in the portion to become the core portion 4 is blocked and the UV light is irradiated only to the side clad layer 22 portion is used, and the side clad layer 22 portion is applied to about 15000 mJ / By performing UV irradiation of cm ² and reducing the refractive index of the side clad layer 22, the core part 4 having a predetermined shape and size was formed and the side clad layer 22 was formed. At this time, since the film thickness in the vicinity of the mirror member 3 is unstable, the pattern of the photomask 21 is designed so that both end faces of the core portion 4 do not overlap the ends of the mirror member 3. Thereafter, baking was performed in an oven at 250 degrees for 2 hours to form the core portion 4 and the side cladding layer 22 having a film thickness of about 40 μm.

  Next, as shown in FIG. 3 (4), polysilane to be the upper clad layer 23 is applied by spin coating so that the film thickness becomes about 33 μm, and baked in an oven at 250 degrees for 2 hours. 23 was formed. The thickness of the upper clad layer 23 after baking was 30 μm. As a result, the optical waveguide 6 having a core width of 40 μm, a core portion 4 of 40 μm, a lower cladding layer 20 and an upper cladding layer 23 of 30 μm, and a total thickness of 100 μm was formed.

  Next, as shown in FIG. 3 (5), the excess polysilane film on the upper surface 11 of the mirror member 3 is removed by polishing, and the surface of Cu forming the mirror member 3 is exposed and the flat upper surface 11 is exposed. Polishing was performed lightly until formed.

  Thereafter, an electrical wiring 9 made of Au was formed on the optical waveguide 6 by a normal photolithography method. A portion of the electrical wiring 9 on which the light emitting element 7 and the light receiving element 8 are mounted is formed by connecting a part thereof to the upper surface 11 of the mirror member 3 so that electrical connection with the conductive mirror member 3 is obtained. . Thereby, the optoelectric wiring board 1 of the present invention was obtained.

  Finally, as shown in FIG. 3 (6), the light emitting element 7 and the light receiving element 8 are positioned with the light emitting part or the light receiving part on the mirror surface 10 of the mirror member 3, and the respective terminal electrodes of the mirror member 3. By connecting to the upper surface 11 and mounting, a photoelectric circuit board in which the light emitting element 7 and the light receiving element 8 are mounted using the photoelectric mounting board 1 of the present invention was completed.

  When the optical insertion loss of the photoelectric wiring substrate 1 of the present invention was measured, it was confirmed that the loss was small and sufficient coupling efficiency was obtained. As a result, according to the present invention, it is possible to obtain an opto-electric wiring board 1 that can easily and stably perform conversion between an optical signal and an electric signal and that can cope with a high-speed signal that cannot be compensated by electricity alone. It could be confirmed.

  In addition, this invention is not limited to the example of the above embodiment, A various change may be added in the range which does not deviate from the summary of this invention. For example, as shown in a sectional view in FIG. 4, the optical waveguide 6 may be sandwiched between the substrate 2 and the upper substrate 12 laminated on the upper surface thereof. At that time, the upper substrate 12 is energized with the optical path via 13 penetrating the upper substrate 12 and the substrate 2 and the mirror member 3 so as to pass the optical signal in a direction perpendicular to the in-plane direction of the upper substrate 12. Penetrating conductors 14 are provided. The optical path via 13 may be disposed above the mirror member 3, and the inside thereof may be air, or may be filled with resin of an optical material or confined by increasing the refractive index of the central portion. The light emitting part and the light receiving part of the light emitting element 7 and the light receiving element 8 are arranged so as to be directly above the optical path via 13 and receive light reflected by the mirror surface 10 while allowing light to enter the optical path via 13. It is combined with the optical waveguide 6 so as to lead to the part. For the energization to the light emitting element 7 and the light receiving element 8, the through conductor 14 may be used, or an electrical wiring (not shown) formed on the upper substrate 12 may be used. In this case, electrical wiring can be performed on the upper substrate 12 using a multilayer printed wiring board or a build-up layer, and various electronic components can be mounted on the upper surface of the upper substrate 12, so that the higher density can be achieved. Complex electrical mounting is possible.

It is a top view which shows an example of embodiment of the optoelectric wiring board of this invention. FIG. 2 is a cross-sectional view taken along line A-A ′ of FIG. 1. (1)-(6) is sectional drawing for every process which shows the example of the production process of the optoelectric wiring board of this invention, respectively. It is sectional drawing which shows the other example of embodiment of the photoelectric wiring board of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Photoelectric wiring board 2 ... Board | substrate 3 ... Mirror member 4 ... Core part 5 ... Cladding part 6 ... Optical waveguide 7 ... Light emitting element 8 ... Light receiving element 9 ···Electric wiring
10 ... Mirror surface
11 ... Top
12 ... Upper substrate
13 ... Optical path via
14 ... Penetration conductor

Claims (7)

A substrate,
A first mirror member disposed on the substrate and formed of a conductive material and having a first mirror surface on a side surface;
A second mirror member disposed on the substrate and formed of a conductive material, the second mirror member having a second mirror surface facing the first mirror surface on a side surface;
The arranged first and second between the mirror surfaces of saw including a clad portion surrounding the core portion and the core portion, the optical waveguide is configured to optically coupled to the mirror surface of the first and second,
Electrical wiring electrically connected to the first and second mirror members,
A light emitting portion is positioned above the first mirror surface , optically coupled to the optical waveguide , and a light emitting element is electrically connected to the upper surface of the first mirror member, and the first mirror portion through wood the light emitting element is electrically connected to the electrical wiring,
A light receiving portion is positioned above the second mirror surface , optically coupled to the optical waveguide , and a light receiving element is electrically connected to the upper surface of the second mirror member, and the second mirror portion through the timber for connecting the light receiving element to the electric wiring, the optical electric wiring board. A light emitting element positioned above the first mirror surface to be optically coupled to the optical waveguide and electrically connected to the upper surface of the first mirror member;
A light receiving element positioned above the second mirror surface, optically coupled to the optical waveguide, and electrically connected to an upper surface of the second mirror member; The optoelectric wiring board according to claim 1. A substrate,
A mirror member disposed on the substrate and formed of a conductive material, and having a mirror surface on a side surface;
An optical waveguide including a core portion and a cladding portion surrounding the core portion, and configured to be optically coupled to the mirror surface;
Electrical wiring electrically connected to the mirror member,
Optically coupled to said optical waveguide to position the light emitting portion above the mirror surface, electrically connected and the light emitting element on an upper surface of the mirror member, the said electrical wiring through the mirror member Connect a light emitting element, or
Optically coupled to said optical waveguide to position the light receiving portion above the mirror surface, electrically connected and the light receiving element on an upper surface of the mirror member, the said electrical wiring through the mirror member An opto-electric wiring board that connects light receiving elements.   A light emitting element positioned above the mirror surface to be optically coupled to the optical waveguide and electrically connected to the upper surface of the mirror member; or
  4. The light receiving device according to claim 3, further comprising: a light receiving element that is positioned above the mirror surface, optically coupled to the optical waveguide, and electrically connected to an upper surface of the mirror member. Optoelectric wiring board. An optical path via for optically coupling one element of the light emitting element and the light receiving element and the mirror surface; and a through conductor electrically connecting the one element and the mirror member;
The optoelectric wiring board according to claim 1, further comprising an upper substrate provided between the one element and the mirror member.   The optoelectric wiring board according to claim 5, wherein the optical path via is provided with an optical material resin having a refractive index at a central portion higher than that at a peripheral portion thereof. The optoelectric wiring board according to claim 1, wherein the mirror member functions as a termination resistor for matching impedance of the electric wiring.

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