JP2005115190A - Opto-electric composite wiring board and laminated optical waveguide structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an opto-electric composite wiring board that can realize high density optical parallel transmission, that can be manufactured at a low cost because of little restrictions on materials and manufacturing methods, and that can be easily miniaturized. <P>SOLUTION: The opto-electric composite wiring board 10 is equipped with a plurality of optical waveguide layers 30, 31, an optical component supporting substrate 11, and a positioning guide member 44 for example. The plurality of optical waveguide layers 30, 31 are arranged by being mutually stacked and are provided with a core 33, a clad 34, an optical path switching part 37, and a positioning hole 36 opening on the main face on the optical waveguide layer side. Light is made to enter or exit through the clad 34. The optical component supporting substrate 11 is provided with the substrate main face 12 and a positioning hole 21 on the substrate side. The positioning guide member 44 is fittingly supported relative to the respective positioning hole 36, 21 on the optical waveguide layer side and on the substrate side in the plurality of optical waveguide layers 30, 31. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an opto-electric composite wiring board and a laminated optical waveguide structure, and more particularly to an opto-electric composite wiring board and a laminated optical waveguide structure characterized by an alignment structure between members.

  In recent years, with the development of information communication technology represented by the Internet and the dramatic improvement in the processing speed of information processing apparatuses, there is an increasing need for transmitting and receiving large-capacity data such as images. An information transmission speed of 10 Gbps or higher is desirable to exchange such a large amount of data freely through an information communication facility, and great expectations are placed on optical communication technology as a technology that can realize such a high-speed communication environment. On the other hand, signals can be transmitted at high speeds even on signal transmission paths at relatively short distances, such as connections between wiring boards in equipment, connections between semiconductor chips in wiring boards, connections within semiconductor chips, etc. It has been desired in recent years. For this reason, it should shift from the conventional transmission form using a metal cable or metal wiring as a transmission medium to the transmission form using an optical fiber or an optical waveguide as a transmission medium. In consideration of mass productivity and cost, a transmission medium using an optical waveguide, particularly a transmission medium using an optical waveguide made of an organic material, is advantageous.

  By the way, in the field of optical wiring in recent years, various types of multi-port optical transceiver modules using optical waveguides have been developed. Such a module is preferable for realizing optical parallel transmission, and is often used in a set with a multi-core optical fiber (so-called tape fiber). Recently, in order to realize higher-density parallel optical transmission, a structure (three-dimensional polymer optical waveguide array) in which multiple so-called multi-core optical waveguides with multiple cores in one layer are stacked has been proposed. (For example, refer to Patent Document 1). In the case of such a prior art structure, a male and female fitting portion is provided in a part of the clad, and the optical waveguides of the respective layers are configured to be aligned with each other by the fitting. The structure is connected to the light emitting / receiving element via a tape fiber. Specifically, one end side of the tape fiber is connected to the light emitting part or the light receiving part of the light emitting / receiving element. On the other hand, the other end side of the tape fiber is connected to the end face (that is, the input / output portion) of the optical waveguide from which the end portion of each core is exposed.

Japanese Patent Laid-Open No. 11-183747 (FIGS. 1, 2, 6, etc.)

  However, in the case of a prior art structure in which the input / output portion exists on the end face of the optical waveguide, the number of optical waveguides increases as the number of ports increases, and the thickness dimension of the structure increases accordingly. End up.

  When the light emitting / receiving element is a light emitting / receiving element (surface light emitting / receiving element) such as a VCSEL having a plurality of light emitting units or a plurality of light receiving units arranged on a predetermined surface, the input / output unit and the surface Connection with a light emitting element becomes difficult.

  Furthermore, if the male / female fitting portion is provided in a part of the clad, the material and manufacturing method of the optical waveguide are limited to, for example, press molding using a specific organic material. This is a factor that hinders cost reduction.

  The present invention has been made in view of the above-described problems, and its object is to realize high-density optical parallel transmission and to easily achieve a reduction in cost because there are few restrictions on materials and manufacturing methods. It is an object of the present invention to provide an optoelectric composite wiring board and a laminated optical waveguide structure that can be easily manufactured.

  And as means for solving the above-mentioned problems, the main surface, the core that becomes the optical path, the clad surrounding the core, the optical path conversion unit that reflects the light and converts the traveling direction thereof, and the opening at least on the main surface A plurality of optical waveguide layers arranged to be stacked on each other, an optical component support substrate having a substrate main surface and a substrate side alignment hole opened at least on the substrate main surface; And an alignment guide member fitted and supported in each optical waveguide layer side alignment hole and the substrate side alignment hole in the plurality of optical waveguide layers, and light is incident through the clad or There is an optical / electrical composite wiring board characterized by emitting light.

  Therefore, according to the present invention, the plurality of optical waveguide layers and the optical component supporting substrate are aligned by fitting the alignment guide members to the alignment holes on the optical waveguide layer side and the alignment holes on the substrate side. The Here, since the alignment guide member separate from the optical waveguide layer and the optical component support substrate is used, there is no need to provide an alignment structure in a part of the optical waveguide layer, and the material of the optical waveguide layer is eliminated. And there are fewer restrictions on selecting a manufacturing method. Therefore, it is easy to achieve cost reduction of the photoelectric composite wiring board by, for example, manufacturing the optical waveguide layer with an inexpensive material or manufacturing method. In addition, since the structure is such that light enters or exits through the cladding, in other words, the input / output section exists on the main surface side of the optical waveguide layer, the input / output section must be disposed on the end face of the optical waveguide layer. Disappear. Therefore, it is possible to increase the number of ports without increasing the number of laminated optical waveguide layers so that an increase in the dimension in the thickness direction can be avoided. Further, for example, the surface-receiving / emitting element may be disposed so as to face the main surface of the optical waveguide layer, so that the surface-receiving / emitting element can be connected to the input / output unit relatively easily. Moreover, since the structure includes a plurality of optical waveguide layers, high-density optical parallel transmission can be realized.

  Further, as another means for solving the above-mentioned problems, the main surface, the core that becomes the optical path, the clad surrounding the core, the optical path conversion unit that reflects light and changes the traveling direction, and at least the main surface The optical waveguide layer-side alignment holes that are opened at a plurality of optical waveguide layers that are stacked on top of each other, and are fitted to and supported by the optical waveguide layer-side alignment holes in the plurality of optical waveguide layers. There is a laminated optical waveguide structure characterized in that a light guide is transmitted through the clad and light enters or exits.

  Therefore, according to the present invention, the alignment guide members are fitted into the alignment holes on the optical waveguide layer side, thereby aligning the plurality of optical waveguide layers. Here, since the alignment guide member separate from the optical waveguide layer is used, there is no need to provide an alignment structure in part of the optical waveguide layer, and the material and manufacturing method of the optical waveguide layer are selected. There are fewer restrictions. Therefore, an optical waveguide layer can be manufactured with an inexpensive material or manufacturing method, and cost reduction can be easily achieved. In addition, since the input / output portion is on the main surface side of the optical waveguide layer, it is not necessary to dispose the input / output portion on the end surface of the optical waveguide layer. Therefore, it is possible to increase the number of ports without increasing the number of laminated optical waveguide layers so that an increase in the dimension in the thickness direction can be avoided. Further, for example, the surface-receiving / emitting element may be disposed so as to face the main surface of the optical waveguide layer, so that the surface-receiving / emitting element can be connected to the input / output unit relatively easily. Moreover, since the structure includes a plurality of optical waveguide layers, high-density optical parallel transmission can be realized.

  The optoelectric composite wiring board and the laminated optical waveguide structure may further include an optical element having at least one of a light emitting unit and a light receiving unit and optically coupled to the core. One or more optical elements are mounted on the main surface of the optical waveguide layer or on the main surface of the optical component supporting substrate in the photoelectric composite wiring substrate. In the laminated optical waveguide structure, one or more optical elements are mounted on the main surface of the optical waveguide layer. As the mounting method, for example, a method such as wire bonding or flip chip bonding, a method using an anisotropic conductive material, or the like can be employed. As an optical element (that is, light emitting element) having a light emitting portion, for example, a light emitting diode (LED), a semiconductor laser diode (LD), a surface emitting laser (Vertical Cavity Surface Emitting Laser; VCSEL), etc. Can be mentioned. These light emitting elements have a function of converting an inputted electric signal into an optical signal and then emitting the optical signal from a light emitting unit toward a predetermined portion. On the other hand, examples of the optical element having a light receiving portion (that is, a light receiving element) include a pin photodiode (pin PD) and an avalanche photodiode (APD). These light receiving elements have a function of causing an optical signal to be incident on the light receiving unit, converting the incident optical signal into an electric signal, and outputting the electric signal. The optical element may have both a light emitting part and a light receiving part. Suitable materials used for the optical element include, for example, Si, Ge, InGaAs, GaAsP, GaAlAs and the like. Such an optical element (particularly a light emitting element) is operated by an operation circuit. The optical element and the operation circuit are electrically connected through a conductor.

  Various electronic components may be mounted on the photoelectric composite wiring board, and various electronic components may be incorporated inside the photoelectric composite wiring board. Specific examples include a semiconductor integrated circuit chip, a semiconductor package, and various chip components (for example, a chip transistor, a chip diode, a chip resistor, a chip capacitor, and a chip coil). All of these electronic components are electrically connected to a conductor formed on the photoelectric composite wiring board.

  The optoelectric composite wiring board and the laminated optical waveguide structure include a plurality of optical waveguide layers arranged to be stacked on each other. These optical waveguide layers are plate-shaped or film-shaped members, and have a core serving as an optical path through which an optical signal propagates and a clad surrounding the core. When the optical waveguide layer is roughly classified from the surface of the forming material, there are an organic optical waveguide layer made of a polymer material or the like and an inorganic optical waveguide layer made of quartz glass or a compound semiconductor. As the polymer material, a photosensitive resin, a thermosetting resin, a thermoplastic resin, or the like can be selected. Specifically, a polyimide resin such as a fluorinated polyimide, an epoxy resin, a UV curable epoxy resin, a PMMA ( Polymethyl methacrylate), acrylic resins such as deuterated PMMA, deuterated fluorinated PMMA, polyolefin resins, and the like are suitable. The advantages of the organic optical waveguide layer are that it can be formed into a flexible film, has excellent handleability, and is relatively inexpensive. On the other hand, the advantage of the inorganic optical waveguide layer is excellent heat resistance.

  In the above-described optoelectric composite wiring board and laminated optical waveguide structure, the number of laminated optical waveguide layers is not particularly limited, and may be an arbitrary number of two or more layers. The plurality of optical waveguide layers arranged in a stacked manner may or may not be fixed to each other using an adhesive or the like. If the plurality of optical waveguide layers are not fixed, the correction work can be easily performed.

  Each optical waveguide layer has an optical waveguide layer side alignment hole into which an alignment guide member can be fitted. The optical waveguide layer side alignment hole is formed so as to open at least on the main surface. That is, the optical waveguide layer side alignment hole may be a non-through hole that opens only on the main surface, or may be a through hole that opens on both the main surface and the opposite side surface. Such alignment holes on the optical waveguide layer side can be formed by a well-known hole processing technique, and specifically, can be formed by a technique such as drilling, punching, etching, or laser processing. . However, from the viewpoint of low cost, machining such as drilling or punching is preferable. Moreover, it is more preferable that the hole processing performed here is a precision hole processing using a precision drill etc., for example. This is because if the alignment recess is formed by such a processing method, alignment can be performed with high accuracy.

  The optoelectric composite wiring board and the laminated optical waveguide structure have an optical path conversion unit that reflects light and converts the traveling direction thereof. For example, the optical path conversion unit may be formed in a part of the optical waveguide layer, or may be formed separately from the optical waveguide layer (that is, an optical path conversion component).

  As a specific example of the optical path changing portion formed in a part of the optical waveguide layer, a concave portion processed into the optical waveguide layer, preferably a V-shaped groove can be mentioned. In this case, the light is reflected by the inner surface of the V-shaped groove and its traveling direction is converted. Even if the optical waveguide layer has a structure in which only a V-shaped groove is formed, it is possible to reflect light and change the optical path, but it is more preferable to reflect a light such as a metal film on the inner surface of the V-shaped groove. It is good to form a body. According to this configuration, it is possible to reflect light efficiently, and light transmission loss can be reliably reduced. As the metal material used for forming the metal film, for example, a glossy metal such as gold, silver, copper, nickel, rhodium or the like is suitable. This is because a glossy metal can reflect light efficiently and is suitable for the application. The metal film preferably reflects 90% or more of light, and particularly preferably totally reflects light. The thickness of the metal film is appropriately set in view of the type of metal material to be used, the thin film formation method, and the like.

  One optical waveguide layer may have a single core or a plurality of cores, but from the viewpoint of realizing high-density parallel optical transmission, a plurality of cores are preferable. For example, when a plurality of cores are formed in parallel in one optical waveguide layer, a V-shaped groove may be formed so as to cross (straddle) the plurality of cores. The depth of the V-shaped groove is not particularly limited, but it is preferable that the depth is at least that the tip reaches the core.

  In addition, it is desirable that the respective optical path conversion units included in the plurality of optical waveguide layers are arranged at positions that do not overlap each other when viewed from the main surface side. In other words, it is desirable that the respective optical path conversion portions included in the plurality of optical waveguide layers are shifted in a direction parallel to the main surface so as not to overlap when viewed from the main surface side. According to this configuration, interference between incident light and outgoing light can be avoided, and optical coupling between the core of the optical waveguide layer and the optical element can be performed without difficulty.

  The optoelectric composite wiring board and the laminated optical waveguide structure include an optical component supporting substrate having a substrate main surface and a substrate-side alignment hole opened at least on the substrate main surface. As the substrate constituting the optical component supporting substrate, for example, a resin substrate, a ceramic substrate, a glass substrate, or a metal substrate can be used, and a ceramic substrate is particularly preferable. When a ceramic substrate having a higher thermal conductivity than that of the resin substrate is used, the generated heat is efficiently dissipated. Therefore, the shift of the emission wavelength due to the deterioration of the heat dissipation property can be avoided, and an optical component supporting substrate excellent in operational stability and reliability can be realized. Preferable examples of such ceramic substrates include substrates made of alumina, aluminum nitride, silicon nitride, boron nitride, beryllia, mullite, low-temperature fired glass ceramic, glass ceramic and the like. Among these, it is particularly preferable to select a substrate made of alumina or aluminum nitride.

  Moreover, as a suitable example of a resin substrate, the board | substrate which consists of EP resin (epoxy resin), PI resin (polyimide resin), BT resin (bismaleimide-triazine resin), PPE resin (polyphenylene ether resin) etc. is mentioned, for example. Can do. In addition, a substrate made of a composite material of these resins and organic fibers such as glass fibers (glass woven fabric or glass nonwoven fabric) or polyamide fibers may be used. Preferable examples of the metal substrate include a copper substrate, a substrate made of a copper alloy, a substrate made of a single metal other than copper, and a substrate made of an alloy other than copper.

  Such a substrate is preferably a wiring substrate provided with an insulating layer and a conductor layer (metal wiring layer). The conductor layer may be formed on the substrate surface or may be formed inside the substrate. In order to achieve interlayer connection between these conductor layers, via hole conductors may be formed inside the substrate. For the conductor layer and via hole conductor, for example, a conductive metal paste made of gold (Au), silver (Ag), copper (Cu), platinum (Pt), tungsten (W), molybdenum (Mo), etc. is printed. Or it is formed by filling. An electric signal flows through such a conductor layer. In addition to such a wiring board, for example, it is allowed to use a build-up wiring board provided with a build-up layer formed by alternately laminating resin insulating layers and conductor layers on the board.

  The shape of the optical component supporting substrate is not particularly limited, but it is preferable that the optical component supporting substrate has a shape having at least one substrate main surface. More preferably, a flat optical component supporting substrate having one or more cavities opened on the substrate main surface side may be used.

  The optical component support substrate has a substrate-side alignment hole that opens at the main surface of the substrate. Such a substrate-side alignment hole may be, for example, a hole provided directly in the substrate material constituting the optical component support substrate. Further, the hole provided directly in the substrate material constituting the optical component supporting substrate may be filled with the filling material, and the hole provided in the filling material may be used as the substrate side alignment hole. As the filling material in this case, it is preferable to use a material that is more workable than the substrate material, for example, a material having a lower hardness than the substrate material. For example, if the substrate material is ceramic, resin, conductive metal, or the like may be selected as the filling material. Further, a guide member support component having a hole into which the alignment guide member can be fitted may be separately manufactured, and this component may be attached to the optical component support substrate. That is, the board-side alignment hole may not be provided directly on the optical component support board.

  The optical component refers to a component having at least one of a light transmission function, a light collection function, and a light reflection function. As specific examples, examples of the optical component having an optical transmission function include an optical waveguide layer and an optical fiber. The base material that supports the optical waveguide layer also corresponds to an optical component having an optical transmission function. Examples of the optical component having a condensing function include a lens component represented by a microlens array. As an optical component having a light reflection function, for example, there is an optical path conversion component. In addition, it can be said that the optical fiber connector in which the optical path changing part is formed is an optical component having a light reflecting function. It can be said that the optical waveguide layer in which the optical path conversion unit is formed is an optical component having an optical transmission function and an optical reflection function.

  The alignment guide member constituting the above-mentioned opto-electric composite wiring board and laminated optical waveguide structure can be fitted to each optical waveguide layer side alignment hole and substrate side alignment hole in a plurality of optical waveguide layers. It has a structure. The shape of the alignment guide member is not particularly limited. For example, a pin-shaped member (guide pin) is preferable, and a material that is hard to some extent is preferable. Such guide pins are preferably fitted into precision machined holes. The number of alignment guide members is not particularly limited, but from the viewpoint of improving alignment accuracy and fixing strength, a plurality of alignment guide members is preferable to a single alignment member. When the alignment guide member is a guide pin, it is preferable to chamfer the outer edge of the end portion of the guide pin. In this way, the guide pin can be easily fitted into the alignment hole.

[First Embodiment]

  DESCRIPTION OF EMBODIMENTS Hereinafter, an optoelectric composite wiring board according to a first embodiment embodying the present invention will be described in detail with reference to FIGS.

  As shown in FIG. 1, the optoelectric composite wiring board 10 of the present embodiment includes an optical element, a ceramic substrate 11 (optical component support substrate), optical waveguide layers 30 and 31, guide pins 44 (positioning guide members). Etc. are constituted.

  As shown in FIGS. 1, 2, and 3, the ceramic substrate 11 constituting the optoelectric composite wiring substrate 10 of the present embodiment is a substantially rectangular plate member having an upper surface 12 (substrate main surface) and a lower surface 13. It is. The ceramic substrate 11 is a so-called multilayer wiring substrate, and includes a metal wiring layer 26 on the upper surface 12, the lower surface 13 and the inner layer. For example, a plurality of connection pads 43 for mounting various electronic components such as an IC chip 42 are formed on a part of the metal wiring layer 26 located on the upper surface 12. The ceramic substrate 11 also includes a via-hole conductor 27, and the metal wiring layers 26 having different layers are connected to each other through the via-hole conductor 27. A plurality of connection terminals 28 are provided on the lower surface 13 of the ceramic substrate 11. In the present embodiment, the metal wiring layer 26, the via-hole conductor 27, the connection terminal 28, and the connection pad 43 are all made of tungsten (W).

  As shown in FIG. 1 and the like, rectangular cavities 41 in which optical elements and the like are arranged are formed at two locations on the upper surface 12 of the ceramic substrate 11. In the left cavity 41 in FIG. 1, a VCSEL 14 which is a kind of optical element (light emitting element) is arranged with the light emitting surface facing upward. The VCSEL 14 has light emitting portions 15 arranged in 4 × 2 rows in the light emitting surface. Accordingly, these light emitting portions 15 emit laser light having a predetermined wavelength in a direction orthogonal to the upper surface 12 of the ceramic substrate 11 (that is, upward direction in FIGS. 1 to 3). On the other hand, in the cavity 41 on the right side in FIG. 1, a photodiode 16 which is a kind of optical element (light receiving element) is arranged with the light receiving surface facing upward. The photodiode 16 has light receiving portions 17 arranged in 4 × 2 rows in the light receiving surface. Accordingly, these light receiving portions 17 are configured to easily receive laser light from the upper side to the lower side in FIG.

  As shown in FIG. 3 and the like, first through holes 21 as first recesses are provided at a plurality of locations (here, 4 locations) in the ceramic substrate 11. The first through hole 21 is circular and has an equal cross-sectional shape, and is open on both the upper surface 12 and the lower surface 13 of the ceramic substrate 11. In the case of the present embodiment, the diameter of the first through hole 21 is set to be about 1.0 mm to 2.0 mm. In the present embodiment, two of the four first through holes 21 are arranged close to the VCSEL 14 and the remaining two are arranged close to the photodiode 16.

  Inside these first through holes 21, a resin filler 22 is provided using a resin paste, and a substrate-side alignment hole 23 (second concave portion) is provided at the substantially central portion of the resin filler 22. Is provided. The substrate-side alignment hole 23 is circular and has an equal cross-sectional shape, and opens on both the upper surface 12 and the lower surface 13 of the ceramic substrate 11. In the present embodiment, the diameter of the substrate side alignment hole 23 is smaller than the first through hole 21 and is set to about 0.7 mm. Inside the four substrate-side alignment holes 23, a guide pin 44 (alignment guide member) made of stainless steel with a circular cross section is fitted with one end protruding toward the upper surface 12 (main surface) side. It is worn. In this embodiment, the outer edge of the end portion of the guide pin 44 is chamfered. Specifically, a guide pin “CNF125A-21” (diameter 0.699 mm) defined in JIS C 5981 is used.

  As shown in FIGS. 1, 2, and 3, two substantially rectangular and film-like optical waveguide layers 30 and 31 that are slightly smaller than the ceramic substrate 11 are stacked on the upper surface 12 side of the ceramic substrate 11. Arranged together. Here, the optical waveguide layer disposed in close contact with the upper surface 12 of the ceramic substrate 11 is referred to as a lower optical waveguide layer 30, and the optical waveguide layer disposed on the upper surface of the lower optical waveguide layer 30 is referred to as the upper optical waveguide. It will be called a waveguide layer 31. These optical waveguide layers 30 and 31 have a core 33 and a clad 34 surrounding the core 33 from above and below. The core 33 substantially becomes an optical path through which light propagates. In the case of the present embodiment, the core 33 and the clad 34 are formed of transparent polymer materials having different refractive indexes, specifically, PMMA (polymethyl methacrylate) having different refractive indexes.

  There are four cores 33 in the lower optical waveguide layer 30, and they are formed so as to extend in parallel and linearly along the lower surface (main surface) of the lower optical waveguide layer 30. The upper optical waveguide layer 31 also has four cores 33, and these are formed to extend in parallel and linearly along the lower surface (main surface) of the upper optical waveguide layer 31. On the lower surface of the lower optical waveguide layer 30, a metal wiring layer 38 having a predetermined pattern made of a conductive metal such as copper is formed. The metal wiring layer 38 extends to the opening edge of the cavity 41 and is electrically connected to the end face of the via-hole conductor 27 included in the ceramic substrate 11. As a result, the lower optical waveguide layer 30 and the ceramic substrate 11 are electrically connected. On the pad formed in a part of the metal wiring layer 38, the terminals of the VCSEL 14 and the photodiode 16 are mounted. Therefore, the light-emitting surface of the VCSEL 14 that is a surface light-emitting element and the light-receiving surface of the photodiode 16 that is a surface light-receiving element are both disposed to face the main surface of the lower optical waveguide layer 30. A driver IC 18 is disposed in the vicinity of the VCSEL 14, and a terminal of the driver IC 18 is also mounted on a pad formed in a part of the metal wiring layer 38. A receiver IC 19 is disposed in the vicinity of the photodiode 16, and a terminal of the receiver IC 19 is also mounted on the pad.

  V-shaped grooves 35 (optical path changing portions) opened on the upper surface of the lower optical waveguide layer 30 are formed at both ends of each core 33 included in the lower optical waveguide 30 so as to cross (straddle) each core 33. Has been. The cores 33 included in the upper optical waveguide layer 31 are formed slightly longer than the cores 33 included in the lower optical waveguide 30. V-shaped grooves 35 (optical path changing portions) opened on the upper surface of the upper optical waveguide layer 31 are formed at both ends of each core 33 included in the upper optical waveguide layer 31 so as to cross (cross) each core 33. ing.

  The VCSEL 14 has two rows of light emitting portions. A V-shaped groove 35 of the lower optical waveguide layer 30 is arranged immediately above one row, and V of the upper optical waveguide layer 31 is placed immediately above the other row. A groove 35 is arranged. The photodiode 16 has two rows of light receiving portions. The V-shaped groove 35 of the lower optical waveguide layer 30 is disposed immediately above one row, and the upper optical waveguide layer path 31 is disposed immediately above the other row. The V-shaped groove 35 is arranged. That is, in the present embodiment, the V-shaped grooves 35 of the two optical waveguide layers 30 and 31 are parallel to the lower surface (specifically, the core 33 of the core 33 so as not to overlap when viewed from the lower surface side). (Displaced in the longitudinal direction). Therefore, interference between incident light and outgoing light can be avoided, and optical coupling between each core 33 and the VCSEL 14 and optical coupling between each core 33 and the photodiode 16 can be performed without difficulty. ing.

  These V-shaped grooves 35 have an inclined surface having an angle of 45 ° with respect to the longitudinal direction of the core 33, and a metal film 37 (light reflector) is provided on the inclined surface. The metal film 37 of the present embodiment is formed by vacuum deposition of a thin film made of rhodium that is glossy and can totally reflect light.

  Circular alignment holes 36 (optical waveguide layer side alignment holes) are formed through the four corners of the lower optical waveguide layer 30 and the upper optical waveguide layer 31, respectively. These alignment holes 36 have a diameter of about 0.7 mm corresponding to the size of the guide pins 44. The guide pins 44 protruding from the ceramic substrate 11 are fitted and supported in the alignment holes 36 of the optical waveguide layers 30 and 31. As a result, the optical waveguide layers 30 and 31 are fixed in an aligned state on the upper surface 12 of the ceramic substrate 11. Here, the “aligned state” specifically refers to a state where the optical axes of the cores 33 and the light emitting units 15 are aligned, and an optical axis of the cores 33 and the light receiving units 17 are aligned. State. In this embodiment, the ceramic substrate 11 and the two optical waveguide layers 30 and 31 are fixed to each other only by the fitting relationship between the alignment hole 36 and the guide pin 44 without using an adhesive or the like.

  A general operation of the optoelectric composite wiring board 10 configured as described above will be briefly described.

  The VCSEL 14 and the photodiode 16 are operable by supplying power from the ceramic substrate 11 side. When an electrical signal is output from the driver IC 18 to the VCSEL 14, the VCSEL 14 converts the input electrical signal into an optical signal (laser light) and then emits the light upward. Light emitted from each light emitting unit 15 belonging to one light emitting unit row is incident from the lower surface of the lower optical waveguide layer 30, passes through the clad 34 of the lower optical waveguide layer 30, and V of the lower optical waveguide layer 30. The groove 35 is reached. Therefore, the light is reflected by the metal film 37 to change the traveling direction by about 90 °, and then propagates in the core 33 of the lower optical waveguide layer 30 to the opposite end along the longitudinal direction. Then, the light reaching the opposite end of the core 33 is reflected again by the metal film 37 of the V-shaped groove 35 to change the traveling direction by about 90 °. The light whose traveling direction is converted downward passes through the clad 34 of the lower optical waveguide layer 30 and is emitted from the lower surface side, and travels in the direction in which the photodiode 16 is present. And light injects into each light-receiving part 17 which belongs to one light-receiving part row | line | column.

  Further, the light emitted from each light emitting unit 15 belonging to the other light emitting unit row of the VCSEL 14 enters from the lower surface of the lower optical waveguide layer 30 and passes through the inside, and then exits from the upper surface. The light emitted from the upper surface of the lower optical waveguide layer 30 then enters from the lower surface of the upper optical waveguide layer 31, passes through the cladding 34 of the upper optical waveguide layer 31, and enters the V-shaped groove 35 of the upper optical waveguide layer 31. It arrives. Therefore, the light is reflected by the metal film 37 to change the traveling direction by about 90 °, and then propagates in the core 33 of the upper optical waveguide layer 31 to the opposite end along the longitudinal direction. Then, the light reaching the opposite end of the core 33 is reflected again by the metal film 37 of the V-shaped groove 35 to change the traveling direction by about 90 °. The light whose traveling direction is converted downward is transmitted through the clad 34 of the upper optical waveguide layer 31 and transmitted through the clad 34 of the lower optical waveguide layer 30, and then is emitted from the lower surface side and travels in the direction in which the photodiode 16 is present. . And light injects into each light-receiving part 17 which belongs to the other light-receiving part row | line | column.

  The photodiode 16 converts a signal included in the light into an electric signal, and outputs the converted electric signal to the receiver IC 19.

  Next, a method for manufacturing the photoelectric composite wiring board 10 having the above-described configuration will be described with reference to FIGS.

  First, the optical waveguide layers 30 and 31 are respectively produced by a conventionally known method, and the alignment holes 36 are formed at the four corners by performing precision drilling on the optical waveguide layers 30 and 31. Specifically, after the lower clad 34, the core 33, and the upper clad 34 are sequentially stacked and formed, precision holes using a precision drill are performed to form alignment holes 36 at predetermined four locations. Further, the metal film 37 is formed by forming a V-shaped groove 35 by dicing and vacuum deposition on the portion. When the V-shaped groove 35 is formed, the position of the alignment hole 36 is preferably used as a reference, and the alignment accuracy can be further improved. Therefore, the optical path changing portion forming step is preferably performed after the alignment recess forming step.

  The lower optical waveguide layer 30 is further sputtered on the lower surface side to form a metal wiring layer 38 having a predetermined pattern. The metal wiring layer 38 may be formed, for example, after the optical path changing portion forming step, or after the alignment concave portion forming step and before the optical path changing portion forming step, or before the aligning concave portion forming step. In this case, etching may be performed in a state where a metal layer is formed on the entire lower surface of the lower optical waveguide layer 30 by plating or the like and a predetermined mask is provided. The VCSEL 14, the photodiode 16, the driver IC 18, and the receiver IC 19 are soldered to the lower optical waveguide layer 30 thus completed by a conventionally known method.

  Further, the ceramic substrate 11 is produced by the following procedure. A raw material slurry is prepared by uniformly mixing and kneading alumina powder, organic binder, solvent, plasticizer, etc., and this raw material slurry is used to form a sheet with a doctor blade device to form a green sheet having a predetermined thickness. . A predetermined portion of the green sheet is punched, and a metal paste for forming a via-hole conductor is filled in the formed hole. Moreover, the printing layer used as a metal wiring layer later is formed by printing a metal paste on the surface of a green sheet. Then, these green sheets are laminated and pressed to be integrated into a green sheet laminate.

  Thereafter, the green sheet laminate is punched to form first through holes 21 (first recesses) (first drilling step). Since it is still unsintered at this stage, drilling can be performed relatively easily and at low cost. In the first drilling step, the inner diameter of the first through hole 21 (first recess) at the time of passing through the firing step is equal to the inner diameter (about 0.7 mm) of the substrate side alignment hole 23 (second recess) and the guide pin 44. The diameter is set to be larger than the diameter (about 0.7 mm), and hole processing is performed. Specifically, the first through hole 21 is drilled by setting to about 1.2 mm to 2.4 mm. The reason is that the ceramic shrinks through the firing process, and accordingly the first through hole 21 is also reduced in diameter and displaced, so this is taken into account and the first through hole 21 is formed larger. It is necessary to keep.

  Next, after performing a drying process, a degreasing process, etc. according to a well-known method, a baking process is further performed at a heating temperature at which alumina can be sintered. As a result, the green sheet laminate (ceramic unsintered body) is sintered to form the ceramic substrate 11. At this point, the ceramic hardens and shrinks.

  In the subsequent resin filling step, the resin filler 22 is provided in the first through hole 21 as follows. First, with respect to 80 parts by weight of bisphenol F type epoxy resin (“Epicoat 807” manufactured by JER) and 20 parts by weight of cresol novolac type epoxy resin (“Epicoat 152” manufactured by JER), a curing agent (“2P4MZ manufactured by Shikoku Kasei Kogyo Co., Ltd.) -CN ") 5 parts by weight, 200 parts by weight of a silica filler (" TSS-6 "manufactured by Tatsumori) treated with a silane coupling agent (" KBM-403 "manufactured by Shin-Etsu Chemical Co., Ltd.), an antifoaming agent (" Sannopco " Berenol S-4 "). This mixture is kneaded with three rolls to be a resin material for forming the resin filler 22. That is, in this embodiment, an uncured resin material containing an inorganic filler in a thermosetting resin is used.

  Next, the ceramic substrate 11 is set in a printing apparatus, and a predetermined metal mask (not shown) is placed in close contact with the upper surface 12 thereof. In such a metal mask, an opening is formed in advance at a location corresponding to the first through hole 21. By printing the resin material through such a metal mask, the resin material is completely filled in the first through holes 21 without any gaps. Thereafter, after the printed ceramic substrate 11 is removed from the printing apparatus, it is heated at 120 ° C. for 1 hour, and the resin filler 22 formed by filling the resin material is semi-cured. Here, the reason why the resin filler 22 is not completely cured is to perform the hole processing in the next second drilling process more easily.

  In the subsequent second drilling step, precision hole machining using a precision drill is performed to form the substrate-side alignment hole 23 (second recess) in the resin filler 22. According to such a processing method, the guide pin 44 serving as a reference for alignment can be the substrate-side alignment hole 23 that can be supported at a desired correct position.

  Next, a main curing process is performed in which the ceramic substrate 11 is heated at 150 ° C. for 5 hours to completely cure the resin filler 22. Further, finishing is performed by a well-known method to finely adjust the hole diameter of the substrate side alignment hole 23 to 0.700 mm. Specifically, the accuracy required for processing at this time is ± 0.001 mm.

  In the subsequent guide member mounting step, the guide pins 44 are fitted into the board-side alignment holes 23 by using a dedicated jig or the like. In the subsequent alignment step, the guide pins 44 protruding from the ceramic substrate 11 are fitted into the alignment holes 36 of the lower optical waveguide layer 30, and then the alignment holes of the upper optical waveguide layer 31. It is made to fit with respect to 36 (refer FIG. 4). As a result, the two optical waveguide layers 30 and 31 are fixed in a state of being aligned with the ceramic substrate 11, and a desired photoelectric composite wiring substrate 10 is completed.

  In addition, you may employ | adopt another method as shown in FIG. First, the two optical waveguide layers 30 and 31 are stacked and disposed, and the guide pin 44 is fitted into each alignment hole 36. Thereby, the laminated optical waveguide structure 51 in a state where the two optical waveguide layers 30 and 31 are aligned and fixed to each other is manufactured in advance. Then, the guide pins 44 protruding from the lower surface side of the laminated optical waveguide structure 51 are fitted so as to be press-fitted into the substrate-side alignment holes 23 of the ceramic substrate 11 (see FIG. 5). Even in this case, a desired photoelectric composite wiring board 10 can be completed.

  Therefore, according to the present embodiment, the following effects can be obtained.

  (1) In this embodiment, guide pins 44 that are separate from the optical waveguide layers 30 and 31 and the ceramic substrate 11 are used as alignment guide members. For this reason, it is not necessary to provide an alignment structure in a part of the optical waveguide layers 30 and 31, and restrictions on selecting a material and a manufacturing method for the optical waveguide layers 30 and 31 are reduced. Therefore, it becomes possible to manufacture the optical waveguide layers 30 and 31 with the above-described inexpensive materials and manufacturing methods, which makes it easy to achieve cost reduction of the opto-electric composite wiring board 10.

  (2) In the present embodiment, a structure in which light enters or exits through the clad 34, in other words, a structure in which the input / output portion is on the lower surface (main surface) side of the optical waveguide layers 30 and 31 is employed. ing. Therefore, unlike the prior art, it is not necessary to dispose the input / output part on the end faces of the optical waveguide layers 30 and 31. Therefore, it is possible to increase the number of ports without increasing the number of laminated optical waveguide layers 30 and 31, and to avoid an increase in the dimension in the thickness direction. For this reason, it becomes easy to achieve miniaturization of the photoelectric composite wiring board 10. In addition, since the VCSEL 14 and the photodiode 16 which are surface-receiving / emitting elements may be disposed to face the lower surfaces of the optical waveguide layers 30 and 31, the surface-receiving / emitting elements can be connected to the input / output unit relatively easily. .

  (4) The photoelectric composite wiring board 10 of the present embodiment has a structure including two optical waveguide layers 30 and 31 having four cores 33, so that high-density optical parallel transmission can be realized. It is.

(5) In this embodiment, the V-shaped grooves 35 (in other words, end portions of the core 33) of the two optical waveguide layers 30 and 31 are arranged so as not to overlap each other when viewed from the lower surface side. ing. Therefore, interference between incident light and outgoing light can be avoided, and optical coupling between each core 33 and the VCSEL 14 and optical coupling between each core 33 and the photodiode 16 can be performed without difficulty.
[Second Embodiment]

  Next, based on FIG. 6, FIG. 7, the optoelectric composite wiring board 10 of 2nd Embodiment is demonstrated.

  In the first embodiment, the metal wiring layer 38 is provided on the lower surface of the lower optical waveguide layer 31, and the VCSEL 14, the photodiode 16, the driver IC 18, and the receiver IC 19 are soldered on the metal wiring layer 38. In contrast, in this embodiment, the metal wiring layer 38 of the lower optical waveguide layer 30 is omitted, and a metal wiring layer 53 is provided on the bottom surface of the cavity 41 of the ceramic substrate 11 instead. The VCSEL 14 and the driver IC 18 are soldered on the metal wiring layer 53.

  In the first embodiment, each core 33 included in the upper optical waveguide layer 31 is formed slightly longer than each core 33 included in the lower optical waveguide 30. Are formed in the same length (see FIG. 6). Instead, the cores 33 of the upper optical waveguide layer 31 and the cores 33 of the lower optical waveguide layer 30 are shifted in the width direction of the core 33 so as not to overlap when viewed from the lower surface side (see FIG. 7). In this case, the shift amount is set to a value that is half the distance between the center lines of the adjacent cores 33. Therefore, also in this embodiment, interference of incident light and outgoing light can be avoided, and optical coupling between each core 33 and the VCSEL 14 and optical coupling between each core 33 and the photodiode 16 are performed without difficulty. It has a configuration that can.

Even with the configuration of the present embodiment, high-density optical parallel transmission can be realized, and there are few restrictions on materials and manufacturing methods, so it is easy to achieve cost reduction and easy to downsize. The wiring board 10 can be provided.
[Third Embodiment]

  Next, the photoelectric composite wiring board 10 of the third embodiment will be described with reference to FIG.

  The optoelectric composite wiring board 10 of the present embodiment includes an optical element, a ceramic substrate 11 (optical component support substrate), a guide pin 44 (positioning guide member), a guide pin support block 61 (guide member support component), and the like. Has been. The guide pin support block 61 is a component manufactured separately from the ceramic substrate 11 and is formed from a rectangular parallelepiped resin lump. The guide pin support block 61 has a guide pin support hole 62 which is a substrate side alignment hole. The guide pin support hole 62 is a through-hole having a circular cross section formed by drilling, and is opened at the upper surface center portion and the lower surface center portion of the guide pin support block 61. The guide pin support block 61 is disposed at the corner portion of the cavity 41 and bonded to the inner surface (specifically, the inner bottom surface and the two inner side surfaces) of the cavity 41 using an organic adhesive. Yes. That is, in the case of this embodiment, the board | substrate side alignment hole is not provided directly in the ceramic board | substrate 11, but it is provided indirectly. The guide pin 44 is fitted and supported in the guide pin support hole 62 of the guide pin support block 61 bonded in this way. As a result, a part of each guide pin 44 protrudes vertically from the upper surface 12 of the ceramic substrate 11.

Even with the configuration of the present embodiment, high-density optical parallel transmission can be realized, and there are few restrictions on materials and manufacturing methods, so it is easy to achieve cost reduction and easy to downsize. The wiring board 10 can be provided.
[Fourth Embodiment]

  Next, the photoelectric composite wiring board 10 of the fourth embodiment will be described with reference to FIG.

  In the case of the photoelectric composite wiring substrate 10 of the present embodiment, a glass ceramic substrate 71 obtained by firing at a low temperature is used instead of the ceramic substrate 11 made of alumina. Further, the metal wiring layer 26, the via-hole conductor 27, the connection terminal 28, and the connection pad 43 are formed of copper (Cu). First recesses 74 are provided at four locations on the glass ceramic substrate 71. The first recess 74 is circular and has an equal cross-sectional shape, and is a non-through hole that opens only on the upper surface 12 of the glass ceramic substrate 71. In this embodiment, the 1st recessed part 74 is formed by the drill process in the stage of the ceramic unsintered body, The diameter is set to about 1.0 mm-2.0 mm. A copper filling portion 73 (metal filling portion) is provided inside the first recessed portion 74, and a pin support hole 72 (second recessed portion, board-side alignment hole) is provided at substantially the center of the copper filling portion 73. ) Is provided. It may be understood that a dummy via-hole conductor is provided inside the first recess 74, and a pin support hole 72 is provided at substantially the center of the dummy via-hole conductor. The copper filling portion 73 is made of the same metal material (that is, copper) as the via hole conductor. The pin support hole 72 is circular and has an equal cross-sectional shape, and is opened only on the upper surface 12 of the glass ceramic substrate 71. In the case of this embodiment, the diameter of the pin support hole 72 is smaller than the first recess 74 and is set to about 0.7 mm.

  A method for manufacturing the glass ceramic substrate 71 having the above-described configuration will be described.

  First, a green sheet is produced according to a conventionally known method, and punching or the like is performed to form via hole holes, cavity holes, and first recesses 74 in predetermined portions. Next, the via hole conductor copper paste is filled into the via hole using a paste printing apparatus, and at the same time, the first recess 74 is filled with the copper paste. Then, the ceramic green body filled with the copper paste is fired at a temperature of about 700 ° C. to 1000 ° C. at which the ceramic can be sintered. As a result, the ceramic green body is sintered to form a glass ceramic substrate 71. At this point, the ceramic hardens and shrinks, and at the same time, the copper paste also sinters and hardens. However, the copper filling portion 73 made of a sintered copper paste has a lower hardness than the glass ceramic substrate 71. Therefore, the machining for the copper filling portion 73 is less difficult than the machining for the glass ceramic substrate 71. Subsequently, precision hole machining using a precision drill is performed to form pin support holes 72 in the copper filling portion 73. As described above, since the copper filling portion 73 is a portion excellent in workability, the pin support hole 72 can be formed relatively easily.

  Even with the configuration of the present embodiment, high-density optical parallel transmission can be realized, and there are few restrictions on materials and manufacturing methods, so it is easy to achieve cost reduction and easy to downsize. The wiring board 10 can be provided.

  In addition, you may change embodiment of this invention as follows.

  The number and shape of the guide pins 44 can be arbitrarily changed without departing from the spirit of the present invention.

  In the first, third, and fourth embodiments, the optical element is mounted on the lower surface of the lower optical waveguide layer 30. However, for example, the optical element can be mounted on the upper surface of the upper optical waveguide layer 31. is there.

  In the third embodiment, the guide pin support block 61 is formed using a resin block as a material, but may be formed using a metal block or a glass block, for example. That is, it is preferable to manufacture the guide pin support block 61 using a material that is not as hard as the main material forming the substrate and is relatively easy to process.

  -In 4th Embodiment, the copper filling part 73 was formed with respect to the glass-ceramic board | substrate 71 which has a conductor part which consists of copper. However, when the glass ceramic substrate 71 has a conductor portion made of, for example, silver, a silver filling portion may be formed instead of the copper filling portion 73. This is because silver, like copper, is a metal that can be co-fired with glass ceramic.

  Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the embodiment described above are listed below.

  (1) A main surface, a core to be an optical path, a clad surrounding the core, an optical path conversion unit that reflects light and changes its traveling direction, and an alignment hole on the optical waveguide layer side that opens at least in the main surface A plurality of optical waveguide layers disposed on top of each other, a substrate main surface, at least a first recess opening in the substrate main surface, a filling body filled in the first recess, and formed in the filling And an optical component support substrate made of ceramic having a substrate-side alignment hole having a diameter smaller than that of the first recess and opening at least on the substrate main surface, and alignment of each of the plurality of optical waveguide layers on the optical waveguide layer side An optoelectronic composite wiring board comprising: a hole and an alignment guide member that is fitted and supported with respect to the substrate side alignment hole, wherein light enters or exits through the clad.

  (2) The photoelectric composite wiring board according to the technical idea 1, wherein the filler is made of a material having better workability than the main material forming the optical component supporting board.

  (3) The technical idea 1 or 2 is characterized in that the optical component supporting substrate is a low-temperature fired ceramic substrate having a conductor portion made of copper or silver, and the filling portion is made of the same metal material as the conductor portion. The photoelectric composite wiring board as described.

  (4) a main surface, a core to be an optical path, a clad surrounding the core, an optical path conversion unit that reflects light and changes a traveling direction thereof, and an alignment hole on the optical waveguide layer side that opens at least in the main surface A plurality of optical waveguide layers stacked on top of each other, an optical component support substrate having a substrate main surface, attached to the substrate main surface side of the optical component support substrate, and having a substrate-side alignment hole A guide member supporting component; and an alignment guide member fitted and supported in each optical waveguide layer side alignment hole and the substrate side alignment hole in the plurality of optical waveguide layers, and transmits the cladding. A photoelectric composite wiring board characterized in that light enters or exits.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic front view which shows the optoelectric composite wiring board of 1st Embodiment which actualized this invention. The principal part expanded sectional view which shows the photoelectric composite wiring board of 1st Embodiment. Sectional drawing in the AA of FIG. The principal part expanded sectional view for demonstrating the manufacturing procedure of the photoelectric composite wiring board of 1st Embodiment. The principal part expanded sectional view for demonstrating another manufacturing procedure of the photoelectric composite wiring board of 1st Embodiment. The principal part expanded sectional view which shows the photoelectric composite wiring board of 2nd Embodiment. Sectional drawing in the BB line of FIG. The principal part expanded sectional view which shows the photoelectric composite wiring board of 3rd Embodiment. The principal part expanded sectional view which shows the photoelectric composite wiring board of 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Photoelectric composite wiring board 11 ... Ceramic substrate as an optical component support substrate 12 ... Substrate main surface 14 ... VCSEL as an optical element
DESCRIPTION OF SYMBOLS 15 ... Light emitting part 16 ... Photodiode as an optical element 17 ... Light receiving part 21 ... Substrate side alignment hole 30 ... (Lower side) Optical waveguide layer 31 ... (Upper side) Optical waveguide layer 33 ... Core 34 ... Cladding 35 ... Optical path conversion V-shaped groove as part 36... Optical waveguide layer side alignment hole 44... Guide pin as alignment guide member 51. Laminated optical waveguide structure 71... Glass ceramic substrate as optical component support substrate 72. Pin support hole as hole

Claims (6)

A main surface, a core to be an optical path, a clad surrounding the core, an optical path conversion unit that reflects light and changes a traveling direction thereof, and an optical waveguide layer side alignment hole that opens at least in the main surface; A plurality of optical waveguide layers disposed on top of each other;
An optical component supporting substrate having a substrate main surface and at least a substrate side alignment hole opened in the substrate main surface;
An alignment guide member fitted and supported in each optical waveguide layer-side alignment hole and the substrate-side alignment hole in the plurality of optical waveguide layers, and light enters or exits through the cladding. An opto-electric composite wiring board characterized by:   The photoelectric composite wiring board according to claim 1, further comprising an optical element having at least one of a light emitting part and a light receiving part and optically coupled to the core.   The photoelectric composite wiring board according to claim 1 or 2, wherein each optical waveguide layer side alignment hole in the plurality of optical waveguide layers is formed by machining.   The optoelectric composite wiring board according to claim 1, wherein the alignment guide member is a guide pin.   5. The light according to claim 1, wherein each of the optical path conversion units included in the plurality of optical waveguide layers is disposed at a position that does not overlap when viewed from the main surface side. Electrical composite wiring board. A main surface, a core to be an optical path, a clad surrounding the core, an optical path conversion unit that reflects light and changes a traveling direction thereof, and an optical waveguide layer side alignment hole that opens at least in the main surface; A plurality of optical waveguide layers disposed on top of each other;
An alignment guide member fitted and supported in each optical waveguide layer side alignment hole in the plurality of optical waveguide layers, wherein the light is transmitted or received through the clad and laminated. Optical waveguide structure.

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