JP2007004043A - Wiring board, module using wiring board, and module assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the optical coupling efficiency of a wiring board, the connection of a waveguide and an optical fiber, and various characteristics of optical coupling density. <P>SOLUTION: The wiring board 10 for coupling an electric signal and an optical signal to surface mounting type optical elements 1 and 2, has: an optoelectic wiring board 15 provided with electric wiring parts 4a and 4b for connecting the electric signal; an optical wiring board M which is mounted on the reverse face of the face on which the optical element of the optoelectic wiring board 15 is provided, and provided with an optical wiring part 13 to which an optical signal is transmitted; and an optical path conversion part 12 provided at the end of the optical wiring part 13. An optical waveguide is provided on an optoelectric wiring board L and passes through the optoelectric wiring board L for connecting the position at which the optical elements 1 and 2 are provided and the optical path conversion part 12, and the optical path conversion part 12 is so formed to convert the optical path between the optical waveguide and the optical wiring part 13. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wiring board and the like used in the network and computer fields, and particularly relates to a structure of a wiring board on which a surface-mounted light emitting element and a light receiving element can be mounted.

  Although speeding up of LSIs is progressing more and more, it is considered that there is a limit in transmission capability for electrical wiring that connects these LSIs. An optical wiring part is expected as a technology that breaks through the limits. Since optical signals have the advantages of high-speed, long-distance transmission capability and low electromagnetic radiation performance, for example, the electrical signal output from the first LSI is converted into an optical signal, and the signal passes through the optical wiring section. After transmission, the optical signal is converted into an electrical signal before the second LSI and then input to the second LSI. Similarly, in the reverse transmission, the electrical signal output from the second LSI is converted into the optical signal. It is considered that the transmission can be performed at a higher speed than the case where only the electric signal is used when the optical signal is converted into the electric signal and the optical signal is changed into the electric signal and input to the first LSI.

  The number of signals input / output from LSIs is increasing year by year, and LSIs having 1000 or more signals are also manufactured. In conventional electrical signal transmission, there is a limit to the distance that high-density electrical wiring can be routed due to the problem of crosstalk between signals. There is great expectation for the introduction of optical wiring parts that have almost no effect.

  In recent years, from the viewpoint of mounting and component costs, a surface-mounted light-receiving / emitting element has attracted attention as an element that performs photoelectric conversion. Since these elements input and output light in a direction perpendicular to the mounting surface, it is necessary to change the optical path when the optical wiring portion is formed in a direction parallel to the substrate. In order to efficiently couple the light input / output from the optical element and the optical wiring part, including the optical path conversion part, with high density, the input / output part of the optical element and the input / output part of the optical wiring part should be as close as possible. Must be implemented.

  There are many conventional techniques related to the optical wiring section. For example, Patent Document 1 has a polymer optical wiring section, Patent Document 2 has a light conversion function in which the end of a waveguide is processed at 45 degrees, Patent Document 3 Reported that an optical wiring part is formed in a printed circuit board. More specifically, in a photoelectric fusion wiring substrate having photoelectric fusion via holes disclosed in Patent Document 3 in a substrate on which optical and electrical wiring are mixedly mounted, a substrate in which electrical wiring and an optical wiring portion are fused is disclosed. The via hole of the present invention shows a structure in which an electrical via hole and an optical via hole coexist, and shows a method using an electrical via hole for low-speed signal transmission and an optical via hole for high-speed signal transmission. Further, in Patent Document 1 (optical wiring section, optical wiring section manufacturing method and multilayer optical wiring section), a structure having a 45-degree mirror and a lens between multilayer optical wiring sections is effective between optical wiring sections of different layers. A technique for propagating light is disclosed. Patent Document 2 (an optical waveguide with a microlens and a manufacturing method thereof) also discloses a structure in which a 45-degree mirror and a lens are provided in a single-layer optical waveguide.

In the field of optical communications, almost all single-mode optical wiring sections are used. This is to avoid signal degradation when transmitting over long distances. However, when a distance of several meters or less in an apparatus such as between LSIs is coupled by an optical wiring unit, if the signal speed is about 20 Gbps, there is no problem in terms of signal degradation even in multimode. Therefore, a multi-mode optical wiring portion having a large mounting tolerance between the optical element and the optical element is mainly used.
JP 2002-258081 A Japanese Patent Laid-Open No. 11-248953 JP 2004-69798 A

  As described above, as a means for solving the problem of high-speed and high-density transmission signals between LSIs, an opto-electric hybrid wiring board in which a multi-mode optical wiring unit is introduced has been studied. There are the following problems.

  (1) Optical coupling efficiency: In the methods proposed so far, the distance between the light emitting / receiving surface of the optical element and the input / output surface of the optical wiring section becomes long, and the coupling efficiency is deteriorated. Condensing function such as is required.

  (2) Bonding of optical waveguide and optical fiber: Polymer optical waveguide has high density and can easily form an arbitrary pattern. If it is a film type, it has good flexibility, and the coefficient of thermal expansion has a value close to that of electrical wiring. . Therefore, compared with an optical fiber, it is suitable for integrating with an electric wiring part at high density and low cost. However, since the propagation loss is larger by one digit or more than the optical fiber, the optical fiber is suitable for a long wiring. Therefore, it is conceivable to use an optical waveguide for optical coupling with an optical element mounted on a printed circuit board at an ultra-high density, and to use an optical fiber for a portion having a long wiring length. In that case, it is necessary to couple the optical waveguide and the optical fiber at high density. In order to efficiently couple an optical connector using an optical fiber and an optical waveguide connector, it is necessary to control the positional accuracy of the connector pins and the optical waveguide. Since the waveguide on the film has limitations in thermal expansion and processing accuracy, it is very difficult to control the positional accuracy, and it is difficult to couple with the optical fiber connector.

  (3) Optical coupling density: Surface-mounted light-receiving and light-emitting elements are in the form of arrays, and the pitch of the light emitting points is the minimum of 250 μm. In order to couple at a pitch of 250 μm or less, it is necessary to reduce the pitch of these optical elements. However, there is a restriction on the size of pads for electrical connection for driving the optical elements, and the pitch is set to 250 μm or less. Is difficult.

  The present invention has been made to cope with such problems, and provides a wiring board capable of improving optical coupling efficiency, bonding between a waveguide and an optical fiber, and various characteristics of optical coupling density, a module using the wiring board, and the like. For the purpose.

  The wiring board of the present invention is a wiring board for connecting an electrical signal and an optical signal to a surface-mount type optical element, and includes an opto-electric wiring board provided with an electrical wiring part for connecting an electrical signal, It has an optical wiring board provided with an optical wiring portion that is provided on the opposite surface of the surface on which the optical element is provided and can transmit an optical signal, and an optical path conversion portion provided at an end of the optical wiring portion. The opto-electric wiring board is provided with an optical waveguide that penetrates the opto-electric wiring board and connects the position where the optical element is provided and the optical path conversion unit, and the optical path conversion unit is an optical path between the optical waveguide and the optical wiring unit. It is formed to convert.

  Therefore, the optical signal propagates in the thickness direction of the photoelectric wiring board from the surface where the optical element is provided, passes through the optical waveguide penetrating the photoelectric wiring board, and reaches the opposite surface of the photoelectric wiring board. Then, the optical path is changed and transmitted to a predetermined connection position by the optical wiring section. As described above, the optical signal can be optically coupled at a propagation distance that is slightly larger than the thickness of the photoelectric wiring board, so that the optical coupling efficiency is improved.

  The optical waveguide may include a via hole penetrating the optoelectric wiring board.

  A metal film may be formed on the inner wall of the via hole.

  The via hole may be filled with a material that is transparent to the optical signal and has substantially the same refractive index as the optical wiring portion.

  The via hole may be formed so that the cross-sectional area increases from the surface on which the optical element of the photoelectric wiring substrate is provided toward the surface on which the optical wiring substrate is provided.

  The via hole may be formed so that the cross-sectional area decreases from the surface on which the optical element of the photoelectric wiring substrate is provided toward the surface on which the optical wiring substrate is provided.

  At least one of the photoelectric circuit board and the optical circuit board may be formed by stacking a plurality of substrates, and the via hole may be formed through the plurality of substrates.

  The photoelectric circuit board may be transparent to the optical signal.

  The optical waveguide may have a via hole penetrating the photoelectric wiring substrate and a transparent material having a higher refractive index than that of the transparent photoelectric wiring substrate filled in the via hole.

  In the transparent wiring substrate, the refractive index of the portion of the optical wiring substrate that is bonded to the photoelectric wiring substrate may be higher than the refractive index of the portion that is not bonded.

  The optical path conversion part has a hemispherical shape, a semi-elliptical shape, a semi-cylindrical shape, or a semi-elliptical columnar shape, and may be formed integrally with the end of the optical wiring part.

  The optical path changing unit may have a metal film in a portion where the optical signal is reflected.

  The optical path conversion unit may have a hemispherical, semi-elliptical, semi-cylindrical, or semi-elliptical columnar mirror surface processed to a thickness substantially equal to that of the optical wiring unit.

  A material that is transparent to the optical signal and has a refractive index similar to that of the optical wiring part may be filled between the end of the optical wiring part and the optical path conversion part.

  An optical element having at least three light receiving units or at least three light emitting units may be mounted, and may be formed so that all of the light path conversion units corresponding to the light receiving units or the light emitting units are not aligned on a straight line. .

  The optical path conversion unit may be formed in a staggered pattern.

  The optical wiring portion may be formed so that the wiring width at the connection portion with the optical path changing portion is wider than the wiring width at other portions.

  The optical wiring portion may be formed such that the wiring width at the connection portion with the optical path changing portion is narrower than the wiring width at other portions.

  The optical wiring part may be formed of a polymer waveguide.

  The polymer waveguide is formed of a core part for propagating an optical signal and a clad part surrounding the core part, and a part of the clad part may constitute a part of the electric wiring part.

  The optical waveguide includes a via hole penetrating the opto-electric wiring board and the cladding portion of the polymer waveguide, and the via hole may be filled with the same material as the core portion of the polymer waveguide.

  The optical wiring portion may be formed in a bendable film shape.

  The optical wiring part may be formed of an optical fiber.

  The optical fiber is surrounded by a polymer material having a refractive index similar to that of the material forming the optical fiber, and the joint surface of the polymer material with the electric wiring portion may be processed flat.

  The optical wiring portion may be formed in a bendable film shape.

  Optical path conversion sections may be formed at both ends of the optical wiring section, and different photoelectric wiring boards may be connected to the end sections.

  A plurality of optical wiring boards may be connected to one photoelectric wiring board.

  An electrical wiring portion may be formed on the optical wiring board, and an electrical signal may be transmitted between the two photoelectric wiring boards via the optical wiring board.

  An optical connector for connecting an optical signal to the outside may be formed at the end of the optical wiring section on the side where the optical path changing section is not formed.

  The optical wiring part is formed in a bendable film shape, and a support body having higher rigidity than the wiring part may be connected to the optical connector.

  A structure having a predetermined positional relationship with the core portion of the optical wiring section may be formed on the support body of the connector, the optical wiring section, or the support body including the optical wiring section.

  The module of the present invention has the above-mentioned wiring board, an optical element mounted on the photoelectric wiring board having at least three or more light emitting parts or at least three light receiving parts, and mounted on the photoelectric wiring board. And an IC chip for operating the optical element.

  The IC chip is mounted on both sides of the optical element, the light emitting part or the light receiving part of the optical element is formed on a straight line, and the optical element is connected to the IC chip for each light emitting part or light receiving part. The electrode may be formed at a position adjacent to the IC chip to which the light emitting part or the light receiving part is connected, for each light emitting part or light receiving part.

  The IC chip is mounted on both sides of the optical element, and the light emitting part or the light receiving part of the optical element is formed on one of the two straight lines. Each light emitting part or light receiving part is a light emitting part or a light receiving part. The optical element has an electrode for electrical connection with the IC chip for each light emitting part or light receiving part, and the electrode is a light emitting part or light receiving part. It may be formed at a position adjacent to the IC chip to which the part is connected.

  A plurality of optical elements may be mounted in two rows, and the IC chip may be mounted on both sides of the plurality of optical elements.

  An optical element having a light emitting element in one column and an optical element having a light receiving element in the other column may be mounted.

  The light emitting units or the light receiving units may be arranged in a staggered manner between each straight line or each column.

  It has two rows of optical elements arranged in a staggered manner, an optical path conversion unit arranged in a staggered pattern, and one optical wiring board, and the two rows of optical elements are connected to corresponding columns of the optical path conversion unit. The optical path conversion unit may be connected to one optical wiring board.

  The module assembly of the present invention includes the above-described plurality of modules and an optical connector that connects the plurality of modules to each other, and one connection portion is provided at one end of the optical connector and at least two are provided at the other end. More than one connecting portions are provided, and the number of branches is equal to the number of IC chips mounted on a module connected to an end portion provided with one connecting portion.

  By using the wiring board of the present invention, optical signals from multi-channel optical elements can be connected to the optical wiring section with high density and low loss. In addition, the optical module using the wiring board according to the present invention can reduce processes that require very high precision alignment when the module is manufactured. Thus, according to the present invention, it is possible to provide a wiring board capable of improving various characteristics of optical coupling efficiency, waveguide and optical fiber bonding, and optical coupling density, and a module using such a wiring board. it can.

  First, the features and actions of the present invention will be described in detail. In the electrical wiring portion for mounting the surface mount type light emitting element and the optical element of the light receiving element, an electrical wiring for driving the optical element is provided on the electrical wiring portion and immediately below the light receiving and emitting point of the optical element. It is possible to suppress the spread of light by providing a via hole in the via hole and transmitting light through the via hole. In addition, the distance between the optical element and the input / output section of the optical wiring section can be shortened by directly connecting the optical wiring section with the optical path conversion section at the input / output end to the electrical wiring section with via holes. Thus, the optical coupling efficiency is improved.

  By plating the inner wall of the via hole with a metal, for example, gold, it is possible to reflect light transmitted through the inside, and to reduce light loss. Further, by filling the via hole with a transparent material having a refractive index comparable to that of the optical wiring portion, it is possible to reduce the loss between the optical element and the optical wiring portion. Furthermore, the optical via hole that is directly under the light emitting portion of the light emitting element has a tapered shape at the top and wide at the bottom. It can be done well. In addition, the optical via hole provided immediately below the light receiving portion of the light receiving element is formed with a narrow upper part and a wide lower part, thereby suppressing the spread of light emitted from the optical wiring part. It becomes possible to couple | bond a part and a light receiving element efficiently. Several layers of optical wiring are formed, and in order to propagate light in a vertical direction to a predetermined layer, by forming a via hole stacked in a layer between the predetermined layer, the lower layer without loss of light It becomes possible to lead to.

  By using a substrate transparent to the light of the light receiving and emitting element in the electrical wiring part, it is possible to couple with the optical wiring part without providing a via hole. However, a via hole is provided and the via hole is transparent. By emphasizing a transparent material having a refractive index higher than that of the substrate, a longitudinal waveguide can be formed, and the optical coupling efficiency can be further improved. In addition, by using a lower transparent substrate for the electrical wiring unit than the optical wiring unit, light that is leaked from the optical wiring unit and causes crosstalk is guided to the bonded transparent electrical wiring unit side. Therefore, highly reliable signal transmission is possible.

  The optical path conversion part has a condensing function, for example, a hemispherical, semi-elliptical, semi-cylindrical, or semi-elliptical mirror, so that light can be efficiently combined. It becomes possible. As this condensing function, a method in which the end portion of the optical wiring portion is directly deformed, a method in which a condensing mirror is formed using a mold or the like at the end portion of the optical wiring portion cut vertically, and the like can be considered. Alternatively, a mirror having a light condensing function and having the same thickness as that of the optical wiring portion may be separately formed and bonded to the end portion of the optical wiring portion. In this case, it is possible to suppress reflection at the interface by filling the space between the end portion of the optical wiring portion and the mirror with a transparent material having the same refractive index as that of the optical wiring portion. Become.

  The optical path conversion unit is not necessarily in a straight line and can be formed at a position corresponding to the mounting position of the optical element. For example, when the light emitting and receiving parts of the optical element are arranged at the staggered position, The optical path conversion unit can also be formed by being arranged at staggered positions corresponding to the optical path conversion unit, and can correspond to high-density optical connection.

  The coupling efficiency can also be improved by forming the optical wiring portion in a tapered shape. The efficiency of light coupling to the core is improved by forming the end of the optical wiring part wider than the other part after the optical path of the light emitted from the light emitting element and passing through the via hole is converted by a mirror. It becomes possible to improve. In addition, a portion formed by making the width of the core at the end of the waveguide narrower than the width of the other optical wiring portion is provided, and the optical path is converted by the mirror at the end, thereby suppressing the spread of light. It becomes possible to couple | bond with a light receiving element efficiently.

  A polymer optical waveguide is used for the optical wiring portion, and the clad layer of the polymer waveguide has the same function as that of the electric wiring portion, thereby shortening the distance between the optical element and the optical wiring portion and improving the coupling efficiency. Further, by providing a via hole in the clad portion and filling the same material as the core layer, a waveguide is formed in the vertical direction, and more efficient optical coupling is achieved through the optical path conversion unit. The polymer waveguide can be formed in a film shape, and the optical wiring portion can be flexibly performed.

  An optical fiber can also be used for the optical wiring portion. The optical fibers are arranged in an array and then integrated with a material having a refractive index similar to that of the optical fiber. The surface to be mounted on the electric wiring portion is processed into a flat surface, and the optical path changing portion is directly formed at the end of the fiber. It becomes possible. The optical fiber can be bent when the diameter is about 80 μm. Since the optical fiber has a propagation loss that is one digit or more smaller than that of the polymer waveguide, the optical fiber is effective when the optical wiring portion of the optical wiring portion joined to the electric wiring portion is long.

  A plurality of optical path conversion elements and a plurality of optical wiring sections can be joined to one electrical wiring section on which a plurality of optical elements are mounted, and a plurality of optical path conversion elements can be attached to one optical wiring section. In addition, it is possible to join the electric wiring portions, and it is possible to perform large-scale photoelectric conversion.

  When electrical wiring can be formed in the optical wiring section, the electrical wiring in the electrical wiring section can be connected to another electrical wiring section through the optical wiring section. No restrictions on the mounting area.

  Since the optical connector is formed at the end of the optical wiring section opposite to the optical path conversion section, the light of the optical element mounted on the electric wiring section can be input / output from / to the outside. In this case, by using a film-like polymer waveguide for the optical wiring portion, it becomes possible to handle the optical connector flexibly, and the degree of freedom of the position at the time of connection is improved. In addition, a support is provided in a film-like polymer waveguide at the portion where the connector is formed, and this support is provided with a structure having a predetermined positional relationship with the core portion of the waveguide, so that the position of the connector pin is provided. Can be aligned.

  In order to perform optical connection at a high density, it is necessary to provide the light receiving and emitting parts of the optical element at a high density and to join the optical wiring part at a high density. The limit of the pitch of the optical element is determined not by the size of the light receiving / emitting part, but by the size of the electrode pad part for operating the optical element. At present, the pad has a minimum diameter of 80 μm, and therefore the pitch of the optical elements is limited to about 250 μm. Therefore, by providing pads on both sides of the arrayed light emitting / receiving portion, the pitch of the light receiving / emitting portions can be 250 μm or less, for example, 125 μm. When combining the electrical wiring section on which this element is mounted and the optical wiring section, the optical path conversion section is provided with a plane mirror or a condensing mirror in an array shape, and the optical wiring section is provided at a pitch of 125 μm, thereby achieving high density. The optical connection is realized. In this case, the IC chip of the driver and receiver for operating the optical element is mounted on both sides of the optical element, so that the length of the electrode between the IC chip and the pad of the optical element can be shortened. A certain photoelectric conversion is realized.

  A 250 μm pitch light emitting / receiving unit is arranged in two rows and arrayed optical elements are used with the column pitch shifted by half, or an arrayed optical device having 250 μm pitch light emitting / receiving units in one row is arranged in two rows. It is also possible to connect 125 μm pitch optical connections by arranging them side by side and shifting the pitch by half. However, in this case, since the light receiving / emitting portions are present at the staggered position, it is necessary to form a staggered structure corresponding to the light receiving / emitting portions at the optical path conversion portion and the waveguide end. The two rows of optical elements can be operated by driver and receiver IC chips that drive different optical elements, respectively. By operating each from both sides, the electrical wiring distance between the IC chip and the optical element can be shortened, so that signal deterioration is hardly caused and photoelectric conversion is realized with high reliability.

  It is possible to mount both a light emitting element and a light receiving element on a single electric wiring part. The arrayed elements are arranged in one row, and the light emitting and receiving parts are arranged in a staggered position. By combining the optical path conversion unit and the optical wiring unit with the optical wiring unit, an optical wiring unit in which a light reception signal and a light emission signal propagate alternately is possible. By alternating transmission and reception, crosstalk between channels can be suppressed, and highly reliable optical transmission is possible.

  A signal from an optical element operating on a plurality of IC chips mounted on one electrical wiring portion is input / output with one connector, and the optical wiring portion connected to this connector is operated for each IC chip. It is possible to branch to. This branch connector is usefully utilized in the case of a system in which distribution is desired for each IC chip.

(First embodiment)
Embodiments of a wiring board according to the present invention will be described with reference to the drawings. First, the configuration of the wiring board will be described. FIG. 1 is a cross-sectional configuration diagram of a wiring board according to an embodiment of the present invention. The wiring board 10 includes an opto-electric wiring board L and an optical wiring board M (see FIG. 11). The optoelectric wiring board L also functions as an insulating layer for the metal wirings 4a and 4b (electrical wiring portions) and as a clad of the optical waveguide cores 5a to 5d. The refractive index is based on the refractive index of the optical waveguide cores 5a to 5d. Is a little smaller and has light transparency. The difference in refractive index between the optical waveguide cores 5a to 5d and the clad (optoelectric wiring board L) is about 0.3 to 2%. The optoelectric wiring board L has a multilayer structure according to a manufacturing method described later, and is composed of layers L1 to L5 in this embodiment.

  The optical waveguide cores 5a to 5d have a size of about 10 to 50 μm. An optical via hole is formed by surrounding the side surfaces of the optical waveguide cores 5a to 5c extending through the opto-electric wiring board L with a clad (the opto-electric wiring board L). On the optoelectric wiring board L, multi-channel optical elements 1 and 2 and the LSI 3 and components (not shown) such as capacitors necessary for driving them are mounted, and a module for realizing various objective functions is obtained. .

  Next, the operation will be described. The electric signal output from the LSI 3 propagates through the metal wirings 4a and 4b of the optoelectric wiring board L, reaches the multichannel optical element 1, and the electric signal is converted into an optical signal. All the multi-channel optical signals are optically coupled to the optical waveguide cores 5a to 5d of the opto-electric wiring board L, and propagated toward the target optical element. The optical signal output from the right end of the multichannel optical element 1 propagates through the optical wiring portion 5d through the bent portion such as the mirror portion 21 and enters the leftmost input channel of the multichannel optical element 2. Three optical signal outputs coming out from the left side of the multi-channel optical element 1 are propagated through the optoelectric wiring board L and reach the back surface of the board. This signal is transmitted to another substrate using an optical connector or an optical fiber (not shown).

  Since the optical wiring portion provided on the optical wiring board M can be configured using a polymer optical waveguide or an optical fiber, it can be bent. In the case of using a plurality of optical fibers, the respective optical fibers 101 to 104 are fixed in parallel so as to be surrounded by a polymer material 105 having a refractive index similar to that of the optical fibers 101 to 104, and the surfaces 106 and 107 that are joined to the electric wiring portion are provided. It is processed so as to be flat (FIG. 10).

  As shown in FIG. 6, the optical waveguide may have a configuration in which a via hole 61 is opened in the photoelectric wiring substrate L and a gold film 62 is formed in the via hole 61. When the light emitted from the VCSEL (surface emitting laser) 63 travels while spreading, it strikes the gold film 62 and is totally reflected and propagates to the lower optical wiring portion 64, so that the optical coupling efficiency is improved. As another structure, the via hole 61 may be transparent to light input to and output from the optical element, and may have a structure in which a material 65 having a refractive index similar to that of the optical wiring portion 64 is filled. By filling the air portion of the via hole 61 with the material 65 having the same refractive index as that of the optical wiring portion 64, the spread of light can be suppressed and the optical coupling efficiency can be increased.

  As shown in FIG. 5, the mirror part 21 can also be formed by embedding a mirror part 51 in which the reflection part is formed of a high reflectance film such as gold. The thickness of the mirror is the same as that of one layer of the optoelectronic wiring board L, and the shape of the reflecting portion can be a hemispherical, semi-elliptical, semi-cylindrical, semi-elliptical columnar structure in addition to a flat surface. By making them equal, the optical coupling efficiency can be increased from the flat surface.

  When the optical element to be mounted is a light emitting element, as shown in FIG. 7A, the shape of the via hole 71 below the light emitting element 72 is wide on the mounting surface side of the light emitting element 72, and A tapered structure on the side of the joint surface can be formed, and the optical coupling efficiency can be increased. When the optical element to be mounted is a light receiving element, as shown in FIG. 7B, the shape of the via hole 74 below the light receiving element 75 is narrow on the mounting surface side of the light receiving element 75, and the optical wiring portion The joining surface side of 76 can have a wide tapered structure, and the optical coupling efficiency can be increased.

  As shown in FIGS. 8 and 9, when the optical wiring portion is viewed from the upper surface, the optical coupling efficiency can be increased by tapering the optical wiring portion core. When optically coupling with the light receiving element, a taper is provided so that the width of the optical wiring core 82 of the optical coupling part 81 with the light receiving element is reduced (FIG. 8). Since the size of the light receiving portion of the light receiving element is reduced as the speed is increased, highly efficient optical coupling can be performed by optical coupling after the optical wiring core 82 is narrowed. When optically coupling with the light emitting element, a taper is provided so that the width of the optical wiring core 84 of the optical coupling part 83 with the light emitting element is increased (FIG. 9). Usually, the light emitted from the light emitting element travels while spreading, so that if the width of the optical wiring core 84 is wide, it is easy to combine.

  Next, the manufacturing method of a wiring board is demonstrated using FIGS. As shown in FIG. 2, the photoelectric circuit board is formed by sequentially laminating layers L5 to L1. The electrical wiring part is manufactured by repeating plating, drilling via holes, and the like. A method for manufacturing an optical via hole will be described with reference to FIG. 3, taking the layer L5 as an example. First, as shown in FIG. 5A, holes 31a to 31c and 32a are formed in the photoelectric wiring board. Processing is performed by laser or lithography. Next, as shown in FIG. 5B, a mask 34 having holes 33a to 33c is prepared at the positions of the holes 31a to 31c where the optical via holes are formed, and the optical waveguide core material is provided through the holes 33a to 33c. 36 is poured, and holes 33a to 33c are filled as shown in FIG. The hole 32a in which the electric via hole is formed is filled by a plating method as shown in FIG.

  A method of manufacturing the optical path changing unit will be described with reference to FIG. FIG. 5A shows the initial state of the layer L4. Next, as shown in FIG. 5B, the portions that become the electrical via hole, the optical via hole, and the optical waveguide core are processed. Further, an optical waveguide core material 44 is poured as shown in FIG. The processing method of the part 41 used as an optical waveguide core is as follows. The simple straight portion 42 can be processed using laser processing or lithography. The oblique portion 43 is processed mainly at 45 degrees. In processing using a laser, a 45-degree surface can be obtained by processing while changing the position and irradiation amount of the laser beam. Specifically, the irradiation amount of the laser beam is increased at a deep processing position. On the contrary, the irradiation amount of the laser beam is reduced at the position where it descends shallowly.

  Lithography can be used when the photoelectric circuit board has photosensitivity. When the optoelectric wiring board is positive, a portion where it is desired to make a deep hole is made transparent with a mask and sufficiently irradiated with light. In the portion where it is desired to create a shallow dent instead of a hole penetrating the layer, the transparency of the mask is reduced and the light irradiation amount is reduced. This is realized by increasing or decreasing the chromium film thickness of the glass mask. A highly reflective material such as gold is deposited on the oblique surface of the opto-electric wiring board so that light propagation proceeds well.

  By performing the above manufacturing method in the order of the layers L5, L4, L3, L2, and L1, a wiring board can be manufactured. That is, the remaining layers are stacked using the layer L5 as a support.

(Second Embodiment)
Another embodiment of the present invention is a structure using an optical waveguide module. For example, a structure having a columnar shape or a V-groove shape for aligning with another waveguide at the end opposite to the optical path changing portion of the waveguide having the optical path changing portion at the end. To do. By having such a structure, high-precision coupling with other optical lines using pins or the like can be easily performed. In the present embodiment, the optical waveguide has flexibility. By having a flexible structure, it is possible to dramatically improve the mountability and workability when inserting and removing the connector, and by utilizing the flexibility, avoiding interference with other parts, the higher It becomes possible to take a dense mounting structure. As an example of the effect when the flexibility of the optical waveguide is used, the degree of freedom in the emission direction of the optical waveguide is increased. Giving the optical waveguide output direction flexibility is very important in order to draw out the optical wiring part from a limited space, assuming cooling of the LSI mounted in the immediate vicinity of the optical waveguide. Is.

  Hereinafter, embodiments of the optical waveguide module of the present invention will be described with reference to schematic views. FIG. 11 is a cross-sectional view showing a schematic configuration when the optical waveguide module of the present invention is used on the light emitting element side. FIG. 12 is a plan view showing a schematic configuration when the optical waveguide module is used on the light emitting element side. FIG. 13 is a cross-sectional view showing a schematic configuration when the optical waveguide module of the present invention is used on the light receiving element side. FIG. 14 is a plan view showing a schematic configuration when the optical waveguide module of the present invention is used on the light receiving element side. The interposer substrate of this embodiment corresponds to the optoelectric wiring substrate L of the first embodiment. Hereinafter, the case where the optical waveguide module is used on the light emitting element side will be mainly described.

  The optical waveguide module shown in FIGS. 11 and 12 includes an optical path conversion unit 12 that guides light and converts an optical path of the guided light, and an optical wiring unit 13 that guides the light that has been optically converted by the optical path conversion unit 12. And have. The optical path conversion unit 12 is in contact with the optical wiring unit 13. On the same side as the light emitting surface of the light emitting element 11 (or the light receiving surface of the light receiving element 21 shown in FIG. 13), an electrical connecting portion for supplying power to drive the light emitting element 11 is provided. The electrical connection portion is solder-connected on the opto-electric wiring board serving as the interposer board 15 (16 and 17 in the figure). A driver IC 6 for driving the light emitting element 11 is soldered on the interposer substrate 15. On the surface of the interposer substrate 15 opposite to the surface on which the light emitting element 11 is mounted, the optical path changing unit 12 is arranged so as to be aligned with a position where the light emitted from the light emitting element 11 passes through the interposer substrate 15. Has been. The light whose optical path has been changed is incident on the optical path conversion section 12 which is aligned and fixed to the interposer substrate 15 and propagates through the optical wiring section 13 after the optical path conversion. As shown in FIGS. 13 and 14, an optical path conversion unit 32 is provided at a position where an optical signal transmitted through the optical wiring unit 13 (33) is emitted from the optical wiring unit 33, at the opposite end of the optical wiring unit 13. In this configuration, the emitted light is optically converted, transmitted through the interposer substrate 35, and incident on the light receiving element 31. A receiver IC 26 for driving the light receiving element 31 is soldered on the interposer substrate 35 in the vicinity of the light receiving element 31.

  The optical characteristics required for the interposer substrates 15 and 35 include a transmittance of 90% or more with respect to the transmission wavelength of the light emitting element 11 in order to transmit the laser light emitted from the light emitting element 11 and to combine it with low loss. It is desirable to have For example, as a specific example of a material having a high transmittance with respect to a transmission wavelength of 850 nm, polyethylene naphthalate, polyimide, pyrex glass, and the like are conceivable. However, the material is not limited to any of a base material and a base material. It is not limited to the above-mentioned several types. In order to realize high-efficiency optical coupling, the distance between the light emitting / receiving portion of the light receiving / emitting element and the mirror surface for changing the optical path is desirably as small as possible, more specifically, 1 mm or less. Is desirable. The optical signal transmitted from the light emitting element 11 has a positive spread angle. Therefore, in order to realize optical coupling with high efficiency, it is necessary to guide light to the optical path conversion unit 12 before the light spreads. Although a method of forming a mirror or the like at a position where the optical signal of the interposer substrate 15 is transmitted and propagating the optical signal as collimated light is also conceivable, this may increase the mounting cost. Therefore, regardless of which method is used, it is desirable that the thickness of the interposer substrate 15 is thinner in the configuration in which the light transmitted through the interposer substrate 15 is collected by the optical path conversion unit 12 and optically coupled.

  The difference in refractive index between the core layer formed on the light emitting / receiving element and the cladding layer, which is the peripheral portion thereof, is desirably 0.5% or more, more preferably greater than 1%. If the refractive index difference is less than this, light confinement becomes incomplete, and crosstalk noise often becomes a problem when the pitch between the waveguide cores is narrow.

  In this embodiment, the polymer waveguide matrix layer has photosensitivity and the refractive index changes by UV light irradiation, but it is not essential that the waveguide matrix layer has photosensitivity. For example, another method such as a method of thermoforming using a mold having unevenness corresponding to a columnar waveguide core formed on the light emitting element may be used. Further, the material used for forming the waveguide desirably has a process temperature of 350 ° C. or lower. When higher temperatures are required, due to the gap between the coefficient of thermal expansion of the polymer waveguide and the semiconductor element, a large internal stress occurs at the interface between the waveguide and the light-emitting element near room temperature, and the mounting reliability of the optical element May be damaged.

  In FIG. 11, it is desirable that the shape of the portion having the function of changing the optical path when an optical signal transmitted from the light emitting element is incident has a condensing function in order to improve the coupling efficiency during the optical path conversion. As an example of a specific shape, it is desirable that it has a hemispherical end face shape and a radius of curvature is 250 μm or less. This is because crosstalk noise between adjacent channels becomes a problem when the radius of curvature is larger than this. Other shapes that can be taken are a semi-elliptical shape, a semi-cylindrical shape, or a semi-elliptical columnar shape.

  The electric signal transmitted from the LSI 3 is transmitted from the output port of the LSI 3 to the driver IC 6 to drive the light emitting element 11. The light emitting element 11 converts an electrical signal into an optical signal of a laser beam and transmits the laser from the light emitting element light emitting portion. The laser-transmitted light passes through the interposer substrate 15 and is optically converted by the optical path conversion unit 12 provided at the end of the optical wiring unit 13. The light whose optical path has been changed propagates in the medium of the optical path converter 12 and enters the core portion of the optical wiring part 13 formed in contact with the optical path converter 12. The optical signal propagating through the waveguide core is converted into an optical path again by a condensing mirror provided at the other end of the optical wiring section 13 and is incident on the light receiving element 31 (FIG. 13). The optical signal of the laser is converted into an electric signal in the light receiving element 31, the receiver IC 26 is driven, and the electric signal reaches the input port of the other LSI 23, thereby exchanging signals with the other LSI 23. be able to.

  Next, a method for manufacturing the optical waveguide module will be described with reference to FIGS. In this embodiment, an example in which an optical waveguide module is manufactured by forming an optical path conversion unit using the same material as the core of the polymer waveguide at the end of the polymer waveguide on the light emitting element side will be described. An element can be manufactured by a similar process. In addition, even if manufactured by other processes, it has a structure that is incident on an adjacent waveguide core after optical path conversion, and the difference in refractive index between the material of the light propagation section of the optical path conversion section and the waveguide core must be small. Thus, it can be used for the optical module of the present invention.

  First, the polymer waveguide 42 is produced on the Si substrate (hard substrate 41). Specifically, a photosensitive layer serving as a base material of the polymer waveguide 42 is applied on a Si wafer by a spin coating method (FIG. 15). Next, the glass waveguide 43 is used for the polymer waveguide layer 42, and the portion that becomes the core layer 47 is UV-exposed with the ultraviolet ray 44 (FIG. 16), and then thermally cured to refract between the exposed portion and the unexposed portion. Create a rate difference. Thereafter, the polymer waveguide base material 45 is applied again and thermally cured, whereby a polymer waveguide 48 having a three-layer structure of the clad layer 46, the core layer 47, and the clad layer 46 can be obtained (FIG. 17). The end surface of the obtained polymer waveguide 48 is cut by dicing, and the end surface is smoothed to form an optical path conversion unit.

  Subsequently, an inversion type for producing the optical path changing unit is produced. First, in order to obtain an inversion-type base material, as shown in FIGS. 18 and 19, a hard base material such as a silicon substrate is etched to produce an inversion-type base material 51 having a smooth gold-plated surface 54. The thickness of the plating layer can be changed depending on the radius of curvature necessary for condensing, and in order to create a condensing surface having a large curvature, the plating layer is formed thick. Subsequently, the gold-plated surface 54 is pressed with a pin 52 having a spherical surface 53 at the tip, thereby forming a condensing mirror reversing die 55 of the optical path conversion unit (FIG. 20).

  Next, the obtained inversion type 55 is fixed so that the position of the center of curvature 58 of the hemispherical portion of the optical path changing portion and the center of the optical waveguide core 57 are aligned (FIG. 21). Thereafter, a photosensitive resin 56 serving as a base material for the optical path changing portion is poured between the hemispherical portion of the inversion type 55 and the waveguide 59 (FIG. 22), and the photosensitive resin 56 is photocured with ultraviolet rays 60. (FIG. 23). By peeling the cured optical path conversion unit 61 from the inversion mold 55 (FIG. 24), a waveguide module 62 in which the optical path conversion unit 61 is in close contact with the end of the waveguide can be formed. A metal plating 63 can be formed on the condensing mirror surface of the obtained optical path changing unit 61 to prevent light leakage and to increase the coupling efficiency (FIG. 25). Thus, the optical wiring unit 13 having the optical path conversion unit 12 is completed.

  As an example of the material of the base material layer of the optical path conversion unit, a material that has photosensitivity and whose refractive index can be changed by light irradiation may be used. However, it is desirable that the shrinkage due to curing is small, and the thermal deformation after forming the optical path changing portion is small. Moreover, it is desirable to use a material having a property close to the refractive index of the core portion of the optical waveguide incident after the optical path conversion by the optical path conversion unit as the material used for the optical path conversion unit. The inversion type of the optical path changing unit is not limited to the manufacturing method described above, and various methods such as machining can be considered. In addition, the optical path conversion unit formed for the above optical path conversion is not limited to a single line, and can be formed in a similar manner even in a plurality of lines.

  Subsequently, a surface-emitting light emitting element 11 having a transmission wavelength of 1000 nm or less, which is formed of a gallium arsenide semiconductor element having a laser transmission wavelength with little absorption of the polymer waveguide, is prepared. Here, the surface-emitting light emitting element refers to an element in which the surface on which the electrode of the light emitting element is formed is the same as the light emitting surface.

  Subsequently, the electrical connection portions of the light emitting element 11 and the light receiving element 31 are soldered to electrode pads on the mother board. Moreover, the optical wiring part 13 which has the optical path conversion part 12 in the position radiate | emitted from a light emitting element is affixed on a motherboard back surface. Similarly, LSI mounting and waveguide pasting were performed on the opposite end face of the optical wiring section 13 to obtain an optical module (FIGS. 11 and 13).

(Third embodiment)
In this embodiment, as a means for changing the optical path, a wedge-shaped process is applied to the end of the waveguide instead of the collecting mirror, and a waveguide layer for converting the optical path to a right angle is formed inside the optical path conversion section. Realizes optical coupling with higher efficiency.

  26 and 27, the light emitting element 11a, the light receiving element 31a, the driver IC 6a, and the receiver IC 26a are aligned and mounted on the interposer substrates 15a and 35a with the same configuration as that of the second embodiment. . In the interposer substrates 15a and 35a on which the light emitting element 11a and the light receiving element 13a are mounted, the optical signal of the light emitting element 11a and the light receiving element 31a passes through the optical signal by a method such as laser processing, drilling, or etching. A hole 19a through which is transmitted is provided, and the wall surface thereof is subjected to surface processing by metal plating, thereby reducing optical signal loss. The light receiving and emitting portions of the light emitting element 11a and the light receiving element 31a and the optical axes of the core layers of the optical wiring portions 13a and 33a whose end surfaces are processed into a wedge shape are fixed to the hole portions. Inside the optical path conversion units 12a and 32a provided on the end face of the waveguide layer, a waveguide core layer that converts the optical path by 90 ° on the wedge-shaped processed surface is formed. By adopting this structure, it becomes possible to suppress the spread of the light of the optical signal transmitted from the light emitting element 11a and the light receiving element 31a. The interposer substrates 15a and 35a are thick, and the interposer substrates 15a and 35a and the optical wiring Even if the coupling distance between the portions 13a and 33a is long, highly efficient optical coupling is possible. The light emitting element 11a has a positive divergence angle, and suppressing the spread of light at a distance corresponding to the thickness of the substrate is very effective in obtaining highly efficient optical coupling.

  Next, the operation of the optical waveguide module of the present embodiment will be shown. First, referring to FIG. 26, an electrical signal transmitted from the LSI 3a is transmitted from the output port of the LSI 3a to the driver IC 6a to drive the light emitting element 11a. The light emitting element 11a converts the electric signal into an optical signal of laser light and transmits the laser beam from the light emitting element light emitting portion. The laser-transmitted light passes through the plated surface of the hole 19a of the interposer substrate 14a while being reflected, and enters the core layer of the optical path changing unit 12a provided on the back surface of the interposer substrate 14a. Incident light is converted into a 90 ° optical path at the core end face processed into a wedge shape, propagates through the core layer, and is transmitted with low loss. Since the columnar waveguide layer 18a is in close contact with the holes 19a provided in the interposer substrate 14a on which the light emitting element 11a is mounted, the light emitted from the light emitting element 11a hardly spreads, and the interposer substrate. Reflected by the wedge-shaped processed surface on the back surface of 14a and converted into an optical axis. Referring to FIG. 27, the reflected light is transmitted through the inside of the waveguide core, is optically converted again by a wedge-shaped optical path conversion surface provided at the other end of the optical wiring portion 33a, and is reflected on the light receiving element 31a. Incident. In the light receiving element 31a, the optical signal of the laser is photoelectrically converted into an electric signal, the receiver IC 26a is driven, incident on the input port of the other LSI 23a, and transmission / reception between the LSIs 3a and 33a can be performed.

  Next, a method for manufacturing the optical waveguide module of the present embodiment will be described. Although a method for manufacturing a module using a light emitting element will be described here, a light receiving element can also be manufactured by a similar process.

  First, a polymer waveguide is produced on a Si substrate by the same method as in the second embodiment. A photosensitive layer serving as a base material for the polymer waveguide is applied on the Si wafer by spin coating (FIG. 15). Using a glass mask on the polymer waveguide layer, a portion serving as a core is UV-exposed (FIG. 16), and then thermally cured, thereby generating a refractive index difference between the exposed portion and the unexposed portion. Then, as shown in the plan view of FIG. 28 and the cross-sectional view of FIG. 29, the polymer waveguide base material 281 is applied again, and as shown in the plan view of FIG. 30 and the cross-sectional view of FIG. Alignment is performed so that the center of the axis is the center of the opening 143a of the mask 43a, and the portion serving as the core is UV-exposed with ultraviolet rays 44a. Thereafter, as shown in FIG. 32, the end surface of the obtained polymer waveguide is cut at 45 ° by a dicing blade 321 to form a wedge shape, thereby forming a wedge shape processed surface 331 shown in FIG.

  Next, as shown in FIG. 34, in the obtained optical wiring portion 13a, the optical axis center of the core layer formed in the optical path changing portion 12a passes through the hole 19a through which the optical axis of the light emitting element 11a of the interposer substrate 14a passes. Align so that it matches the center of. Further, the electrode pad 111 of the light emitting element 11 a on which the waveguide layer is formed and the electrode pad 141 formed on the interposer substrate 14 a are connected by solder 341. Similarly, the light receiving element 31a is soldered to the opposite end face of the waveguide to complete the optical module.

(Fourth embodiment)
As a fourth embodiment of the present invention, an example is shown in which a connector for optical coupling with a quartz fiber is formed at one end of a waveguide layer having flexibility. FIG. 35 is a cross-sectional view showing the module of the present embodiment. FIG. 36 is a side view of the present embodiment as viewed from the connector side. The optical wiring portion 13b has flexibility, and as shown in FIG. 36, a V-groove-shaped recess 361 formed directly on the optical wiring portion 13b is provided at one end of the optical wiring portion 13b. . The concave portion 352 is used for positioning when performing alignment processing with the quartz fiber waveguide when the connector 351 is formed. The waveguide end is molded and sealed with a sealing resin 363. Cylindrical holes 362 are formed at both ends of the molded and sealed component, and positioning with other components is possible by inserting a pin into the hole 362. The position of the hole 362 is formed such that the core center of the optical wiring portion 13b coincides with the line connecting the centers of the holes 362 at both ends.

  Although not shown in the drawing, a part is prepared in which two cylindrical holes are formed and the cores of the quartz fiber waveguide are arranged on a line connecting the holes. This cylindrical hole has the same dimensions as hole 362, such as size and distance between holes. By inserting a pin into the cylindrical hole, the optical signal emitted from the light emitting element is optically coupled and transmitted. It has a structure that can be done. In the present embodiment, since the interposer substrate and the waveguide have flexibility, the optical wiring portion can be pulled out of the substrate at a free angle. When producing a multi-channel high-density module, the thermal density generated by the light emitting / receiving element, its driver, receiver and CPU is high, and it is necessary to mount a very large heat sink to cool it. For this reason, it is very important that the degree of freedom of mounting is high, but if the module of this embodiment is used, the problem of degree of freedom of mounting can be solved.

  Next, the operation of this embodiment will be described. An electric signal transmitted from an LSI (not shown) is transmitted from the output port of the LSI to the driver IC 6b to drive the light emitting element 11b. The light emitting element 11b converts the electric signal into an optical signal of laser light, and transmits the laser from the light emitting element light emitting portion. The optical signal transmitted from the light emitting element 11b passes through the flexible interposer substrate 14b, enters the optical path conversion unit 12b, and is optically converted. The optical signal subjected to the optical path conversion is incident on the core 131 in the clad 132 of the optical wiring section 13b adjacent to the optical path conversion section 12b. The optical signal incident on the core 131 propagates through the core of the optical wiring portion 13b and reaches the end of the optical wiring portion 13b. The optical signal that has reached the end portion passes through the connector 351 aligned by positioning holes formed at both ends of the molded sealing component, and enters the waveguide core of the quartz fiber. The optical signal incident on the waveguide core of the quartz fiber passes through a connector (not shown) provided at the other end of the waveguide, and is subjected to 90 ° optical path conversion by an optical path conversion unit provided at the end of the waveguide. Then, the light is incident on a light receiving element (not shown). The optical signal of the laser is converted into an electrical signal in the light receiving element, a receiver IC (not shown) is driven, and incident on the input port of the other LSI, thereby transmitting / receiving to / from the other LSI. Can do.

  Next, the manufacturing method of this module is demonstrated. Here, an example in which a polymer waveguide is formed on a light-emitting element will be described, but a light-receiving element can also be manufactured by a similar process.

  In the same configuration as in the second embodiment, the light emitting element and the driver IC are positioned and mounted on an interposer substrate having flexibility. Subsequently, the support substrate at the time of waveguide preparation is left at the end of the polymer waveguide, and the support substrate is processed to enable coupling with other waveguides and other optical elements to form a film waveguide. An example will be described.

  First, a substrate having flatness and UV transmission is prepared, and an adhesive layer on which adhesion strength with the substrate is reduced by UV irradiation is formed thereon. Subsequently, a protective layer that does not transmit UV is formed on the adhesive layer, and coating, exposure and curing of the clad layer, the core layer, and the clad layer of the polymer waveguide are repeated on the protective layer. Form. When UV light is irradiated from the opposite side of the obtained optical waveguide layer and the UV adhesive layer is cured, the adhesive layer is cured and contracted, and the adhesion strength between the substrate and the waveguide is lowered. When the adhesion strength is reduced, the hard substrate is removed to form a polymer film waveguide.

  The protective layer serves to prevent the adhesion strength of the adhesive layer from being lowered and peeled off by the UV light irradiated during the waveguide fabrication exposure. As the UV adhesive layer, a layer having a mechanism for reducing adhesion by foaming a foaming agent contained in the adhesive layer by UV light and generating gas may be used. By using the adhesive layer having such a mechanism, the support substrate can be locally peeled by UV irradiation, and the waveguide can be peeled with low stress. By adopting the method as described above, the support for the polymer waveguide can be removed without any trouble at the time of peeling the polymer waveguide. In addition, a method of forming a waveguide on a substrate that does not transmit UV, peeling the polymer waveguide with heat or a solvent, and forming a film is also possible, but it is not suitable for cases where it is desired to leave a hard substrate locally. is there.

  The adhesive layer and the protective layer that does not transmit light at the time of waveguide exposure are more desirable as long as they have both properties. Examples of the protective layer include polyimide and the like, and have flexibility and heat resistance. It is desirable that the material can form the wiring.

  There are various materials such as polyimide-based, benzocyclobutene-based, epoxy-based, silicon-based, and acrylic-based polymer waveguides formed on a hard substrate, but they are formed at the end of the waveguide when transmitting / receiving to / from other boards. In consideration of the mountability when inserting / removing the connector to be inserted and the degree of freedom in the direction in which signals are transmitted / received to / from the motherboard, it is desirable to have flexibility with a curvature radius of 30 mm or less.

  Next, a groove 361 is formed by a dicing saw on the waveguide forming surface side of the sample having the waveguide formed on the obtained support base material. Using a V-shaped blade, the tip shape was formed so as to reach the hard substrate 364. After forming the V-groove, both ends of the waveguide pattern were left from the glass surface side, and a kerf was formed. Subsequently, UV light was irradiated only on the part to be filmed from the glass surface side. When nitrogen was generated from the foaming agent contained in the adhesive layer, an air layer was formed at the interface between the glass and the adhesive layer, and the glass could be easily peeled off. Using the V-groove processing formed at the end of the obtained film waveguide, it can be aligned with the protrusion of the connector fitting portion and optically coupled with the quartz fiber.

  The material of the transparent substrate that is the support substrate described above is not particularly limited to a non-base material such as glass as long as it is flat and can transmit UV light. An organic film material such as polyimide, polyethylene terephthalate, and polyethylene naphthalate can be processed in the same manner, and can be properly used depending on the intended use, such as required heat resistance, weight, and light transmittance.

  In addition, by performing the film forming process similar to the above on both sides of the polymer waveguide, the supporting base material can be left in a structure sandwiching the waveguide. When bonding with the quartz fiber, it is possible to reduce the optical axis shift at the time of thermal cycle application by sandwiching a support base material layer having a low linear expansion coefficient. In the case of forming a multi-layered waveguide, etc., the influence of the optical axis shift appears more severely, so it is effective to take the above method.

  The processing of the support substrate at the waveguide end described above is not limited to the V-groove processing described above. As examples of other shapes, it is also possible to align using a method of aligning and coupling using pins, or using unevenness formed by waveguide exposure.

  Further, the support base material is not limited to the case where the support base material is formed only on one side of the polymer waveguide, and the support base material is left on both surfaces of the polymer waveguide to form an optical module.

  The optical path conversion part having the light condensing function shown in the second embodiment was formed at the other end of the flexible polymer waveguide having a connector formed at one end obtained as described above. The obtained optical waveguide module is aligned with a flexible interposer substrate and attached with an adhesive to complete the optical module of the embodiment.

(Fifth embodiment)
In the module of this embodiment, the optical waveguide tip is formed in a staggered arrangement. FIG. 37 shows a plan view of the module of the fifth embodiment. FIG. 5A is a view seen from the optical element mounting surface, and FIG. 9B is a view seen from the optical waveguide surface. On the optical element mounting surface, optical elements 371a and 371b each having a 1 × 12 ch configuration and corresponding driving ICs 372a and 372b each having a 1 × 12 ch configuration are mounted. In the case where two optical elements are provided, there are three configurations in which both are light emitting elements, both are light receiving elements, and one light emitting element and one light receiving element are provided. On the optical waveguide surface opposite to the optical element mounting surface, a total of 24 optical waveguides 373, which are optical wiring portions, are provided in two sets of 12 rows. The tips of the optical waveguides 373 are staggered in each row and are staggered. By arranging the optical elements in a staggered manner in this way, the pitch of the optical wiring portion can be reduced to half the pitch of the optical elements, and the density of the optical wiring portion is doubled.

  Here, a configuration in the case where a 12ch optical element is driven by a 12ch IC is shown, but another configuration can be used. For example, as shown in FIG. 38A, one optical element 381 may be mounted in 1 × 12ch, and 6ch ICs 382a and 382b may be mounted on both sides of the optical element. As shown in FIGS. 38 (b1) and (b2), which are enlarged views of part A in FIG. 38 (a), the optical element pad 384 can be disposed at a position close to one of the ICs 382a and 382b. Each optical element is electrically connected to the IC with the pad 384 closer through the wiring board. Further, as shown in FIG. 38 (c), one 2 × 6ch optical element 383 may be mounted, and ICs 382a and 382b may be mounted on both sides thereof. In this case, the pad 384 of the optical element is provided on the side closer to the IC so as to shorten the electrical wiring distance as shown in FIG. Electrical wiring is performed between the element and the IC.

  As shown in FIG. 39, connectors 394 can be provided at the ends of the modules 391 to 393 to connect the modules. The optical wiring portion 395 is branched according to the number of ICs, and the respective modules are connected. Since the module 391 has two ICs 396, the module 391 branches at a branch 395 and is connected to modules 392 and 393 each having one IC 396.

It is a section lineblock diagram of a wiring board concerning one embodiment of the present invention. It is explanatory drawing which shows the manufacturing method of a wiring board. It is explanatory drawing which shows the manufacturing method of a wiring board. It is explanatory drawing which shows the manufacturing method of a wiring board. It is explanatory drawing which shows the structural example of a mirror part. It is explanatory drawing which shows the modification of a wiring board. It is explanatory drawing which shows the modification of a via hole. It is explanatory drawing which shows the modification of an optical wiring part core. It is explanatory drawing which shows the modification of an optical wiring part core. It is a conceptual diagram which shows the edge part process in the case of using two or more optical fibers. It is sectional drawing which shows schematic structure at the time of using the optical waveguide module of this invention for the light emitting element side. It is a top view which shows schematic structure at the time of using an optical waveguide module for the light emitting element side. It is sectional drawing which shows schematic structure at the time of using the optical waveguide module of this invention for the light receiving element side. It is a top view which shows schematic structure at the time of using the optical waveguide module of this invention for the light receiving element side. It is explanatory drawing which shows the manufacturing method of an optical waveguide module. It is explanatory drawing which shows the manufacturing method of an optical waveguide module. It is explanatory drawing which shows the manufacturing method of an optical waveguide module. It is explanatory drawing which shows the manufacturing method of an optical waveguide module. It is explanatory drawing which shows the manufacturing method of an optical waveguide module. It is explanatory drawing which shows the manufacturing method of an optical waveguide module. It is explanatory drawing which shows the manufacturing method of an optical waveguide module. It is explanatory drawing which shows the manufacturing method of an optical waveguide module. It is explanatory drawing which shows the manufacturing method of an optical waveguide module. It is explanatory drawing which shows the manufacturing method of an optical waveguide module. It is explanatory drawing which shows the manufacturing method of an optical waveguide module. It is explanatory drawing which shows other embodiment of an optical waveguide module. It is explanatory drawing which shows other embodiment of an optical waveguide module. It is explanatory drawing which shows the manufacturing method of the optical waveguide module shown in FIG. It is explanatory drawing which shows the manufacturing method of the optical waveguide module shown in FIG. It is explanatory drawing which shows the manufacturing method of the optical waveguide module shown in FIG. It is explanatory drawing which shows the manufacturing method of the optical waveguide module shown in FIG. It is explanatory drawing which shows the manufacturing method of the optical waveguide module shown in FIG. It is explanatory drawing which shows the manufacturing method of the optical waveguide module shown in FIG. It is explanatory drawing which shows the manufacturing method of the optical waveguide module shown in FIG. It is explanatory drawing which shows other embodiment of an optical waveguide module. It is the side view seen from the connector side of the optical waveguide module shown in FIG. It is explanatory drawing which shows other embodiment (5th Embodiment) of an optical waveguide module. It is explanatory drawing which shows the relationship between an optical element and IC. It is explanatory drawing which shows the method of connecting a some module.

Explanation of symbols

3,23 LSI
4a, 4b Metal wiring 5a-5d Optical waveguide core 6 Driver IC
DESCRIPTION OF SYMBOLS 10 Wiring board 11 Light-emitting element 12 Optical path conversion part 13 Waveguide 15, 35 Interposer board 26 Receiver IC
31 Photodetector 61 Via hole L Photoelectric wiring board

Claims (39)

A wiring board for connecting an electrical signal and an optical signal to a surface-mount optical element,
An opto-electric wiring board provided with an electric wiring part for connecting the electric signal;
An optical wiring board provided with an optical wiring portion that is provided on a surface opposite to the surface on which the optical element of the photoelectric wiring board is provided, and that transmits the optical signal;
An optical path conversion unit provided at an end of the optical wiring unit;
Have
The opto-electric wiring board is provided with an optical waveguide that penetrates the opto-electric wiring board, connecting the position where the optical element is provided and the optical path conversion unit,
The wiring board is formed so that the optical path conversion unit performs optical path conversion between the optical waveguide and the optical wiring unit.   The wiring board according to claim 1, wherein the optical waveguide includes a via hole penetrating the photoelectric wiring board.   The wiring board according to claim 2, wherein a metal film is formed on an inner wall of the via hole.   The wiring board according to claim 2, wherein the via hole is filled with a material that is transparent to the optical signal and has substantially the same refractive index as the optical wiring portion.   The said via hole is formed so that a cross-sectional area may expand toward the surface where the said optical circuit board is provided from the surface where the said optical element of the said photoelectric circuit board is provided. The wiring board according to item 1.   5. The via hole according to claim 2, wherein the via hole is formed so that a cross-sectional area decreases from a surface on which the optical element is provided on the optoelectric wiring substrate to a surface on which the optical wiring substrate is provided. The wiring board according to item 1. At least one of the photoelectric wiring board or the optical wiring board is formed by laminating a plurality of substrates,
The wiring board according to claim 2, wherein the via hole is formed through the plurality of substrates.   The wiring board according to claim 1, wherein the optoelectric wiring board is transparent to the optical signal. The optical waveguide is
A via hole penetrating the optoelectric wiring board;
A transparent material filled in the via hole and having a refractive index higher than that of the transparent photoelectric wiring board;
The wiring board according to claim 8, comprising:   10. The transparent wiring substrate according to claim 8, wherein a refractive index of a portion of the optical wiring substrate that is bonded to the photoelectric wiring substrate is higher than a refractive index of a portion that is not bonded. Wiring board.   The wiring according to claim 1, wherein the optical path conversion unit has a hemispherical shape, a semi-elliptical shape, a semi-cylindrical shape, or a semi-elliptical column shape, and is formed integrally with an end of the optical wiring unit. substrate.   The wiring board according to claim 11, wherein the optical path conversion unit has a metal film in a portion where the optical signal is reflected.   The said optical path conversion part has the mirror surface of the hemispherical shape, semi-elliptical shape, semi-cylindrical shape, or semi-elliptical column shape processed to the thickness substantially equivalent to the said optical wiring part. Wiring board.   The material between the end of the optical wiring part and the optical path conversion part is filled with a material that is transparent to the optical signal and has a refractive index similar to that of the optical wiring part. Wiring board.   The optical element having at least three light receiving portions or at least three light emitting portions is mounted, and is formed so that all of the optical path changing portions corresponding to the light receiving portions or the light emitting portions are not aligned on a straight line. The wiring board according to claim 1.   The wiring board according to claim 15, wherein the optical path conversion unit is formed in a staggered pattern.   The wiring substrate according to claim 1, wherein the optical wiring portion is formed so that a wiring width at a connection portion with the optical path changing portion is wider than a wiring width at other portions.   The wiring substrate according to claim 1, wherein the optical wiring portion is formed such that a wiring width at a connection portion with the optical path changing portion is narrower than a wiring width at other portions.   The wiring substrate according to claim 1, wherein the optical wiring portion is formed of a polymer waveguide.   The polymer waveguide is formed of a core part for propagating the optical signal and a clad part surrounding the core part, and a part of the clad part constitutes a part of the electric wiring part. The wiring board according to claim 19. The optical waveguide includes a via hole that penetrates the clad part of the photoelectric wiring substrate and the polymer waveguide,
The wiring board according to claim 20, wherein the via hole is filled with the same material as the core portion of the polymer waveguide.   The wiring substrate according to claim 19, wherein the optical wiring portion is formed in a bendable film shape.   The wiring board according to claim 1, wherein the optical wiring portion is formed of an optical fiber.   The optical fiber is surrounded by a polymer material having a refractive index similar to that of a material forming the optical fiber, and a joint surface of the polymer material with the electric wiring portion is processed to be flat. The wiring board described.   The wiring substrate according to claim 23, wherein the optical wiring portion is formed in a bendable film shape.   The wiring board according to claim 1, wherein the optical path conversion sections are formed at both ends of the optical wiring section, and the different photoelectric wiring boards are connected to the end sections.   The wiring board according to claim 1, wherein a plurality of the optical wiring boards are connected to one optoelectric wiring board.   The wiring board according to claim 1, wherein the electrical wiring portion is formed on the optical wiring board, and the electrical signal is transmitted between the two optoelectric wiring boards via the optical wiring board.   The wiring board according to claim 1, wherein an optical connector for connecting the optical signal to the outside is formed at an end portion of the optical wiring portion on the side where the optical path changing portion is not formed.   30. The wiring board according to claim 29, wherein the optical wiring portion is formed in a bendable film shape, and a support having a rigidity higher than that of the wiring portion is connected to the optical connector.   The structure having a predetermined positional relationship with the core portion of the optical wiring section is formed on the support body of the connector, the optical wiring section, or the support body including the optical wiring section. Wiring board. The wiring board according to claim 1;
The optical element mounted on the optoelectric wiring board, having at least three or more light emitting portions or at least three or more light receiving portions;
An IC chip for operating the optical element mounted on the optoelectric wiring board;
Having a module. The IC chips are respectively mounted on both sides of the optical element,
The light emitting part or the light receiving part of the optical element is formed on a straight line,
The optical element has an electrode for electrical connection with the IC chip for each light emitting unit or light receiving unit, and the electrode is connected to the light emitting unit or light receiving unit for each light emitting unit or light receiving unit. 33. The module according to claim 32, wherein the module is formed at a position adjacent to the IC chip being formed. The IC chips are respectively mounted on both sides of the optical element,
The light emitting part or light receiving part of the optical element is formed on one of two straight lines, and each light emitting part or light receiving part is electrically connected to the IC chip adjacent to the straight line on which the light emitting part or light receiving part is formed. Connected,
The optical element has an electrode for electrical connection with the IC chip for each of the light emitting part or the light receiving part, and the electrode is adjacent to the IC chip to which the light emitting part or the light receiving part is connected. The module of claim 32, wherein the module is formed in position.   The module according to claim 32, wherein the plurality of optical elements are mounted in two rows, and the IC chip is mounted on both sides of the plurality of optical elements.   36. The module according to claim 35, wherein the optical element including the light emitting element in one column is mounted, and the optical element including the light receiving element in the other column is mounted.   The module according to any one of claims 34 to 36, wherein the light emitting units or the light receiving units are arranged in a staggered manner between the straight lines or the columns. Two rows of optical elements arranged in a staggered manner;
The optical path converters arranged in a staggered pattern;
One optical wiring board;
Have
The optical elements of the two rows are connected to corresponding rows of the optical path changing unit,
The optical path changing unit is connected to the one optical wiring board,
38. The module of claim 37. A plurality of modules according to claim 32;
An optical connector for connecting the plurality of modules to each other;
Have
One end of the optical connector is provided with one connecting portion, and the other end is provided with a connecting portion branched into at least two,
The number of the branches is a module assembly equal to the number of the IC chips mounted on the module connected to the end provided with the one connection portion.

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