JP2012103381A - Manufacturing method for photoelectric composite wiring board, and photoelectric composite wiring board manufactured by the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a photoelectric composite wiring board which can realize a composite of an optical waveguide and an electric circuit with high adhesion, thereby enabling a manufacture of the photoelectric composite wiring board with no loss in the optical waveguide or no coupling loss between a light reception element and an optical circuit.SOLUTION: A manufacturing method for a photoelectric composite wiring board comprises: a core formation step of forming a core 13 on a first clad layer 12 formed on a substrate 16; a clad layer formation step of forming a clad layer by laminating a second clad material layer 17 including an uncured resin composition so as to embed the core formed on the first clad layer 12; a metal layer formation step of forming a metal base layer 16 having at least one surface thereof roughened, on the second clad material layer 17; a curing step of curing the uncured resin composition of the second clad material layer 17 to form a second clad layer 18; and an electric circuit formation step of forming an electric circuit on the metal base layer 16. The surface roughness Rz of the metal base is preferably 0.5 μm or more and 5 μm or less.

Description

  The present invention relates to a method for manufacturing a photoelectric composite wiring board, and a photoelectric composite wiring board manufactured by the manufacturing method.

  Conventionally, an optical fiber has been mainly used as a transmission medium in FTTH (Fiber To The Home) and long-distance and medium-distance communication in the in-vehicle field. However, in recent years, high-speed transmission using an optical medium has become necessary even at a short distance within 1 m. In this high-speed transmission over a short distance, high-density wiring (narrow pitch, branching, crossing, multilayering, etc.), surface mountability, integration with an electric substrate, and bending with a small diameter are possible instead of the optical fiber. Therefore, an optical waveguide type optical wiring board is suitable.

  To make the optical wiring board, two types of replacement are necessary. One is replacement of a printed circuit board (PWB) used for a printed wiring board, and the other is replacement of a flexible printed circuit board (FPC) used for a hinge of a small terminal device. In either type, it is indispensable to transmit electrical wiring and low-speed signals for operating a VCSEL (Vertical Cavity Surface Emitting Laser), PD (Photo Diode), or IC, which is a light emitting / receiving element. The form of the photoelectric composite wiring board in which the electric circuit is mixed is ideal.

  As a method of combining the optical waveguide and the electric circuit in order to obtain the form of the photoelectric composite wiring board as described above, for example, there is a method of directly forming a metal layer on the optical waveguide. In order to form the metal layer directly on the optical waveguide, it is necessary to form an unevenness by chemical treatment of the material so that an anchor effect can be obtained. However, since normal materials have transparency, the structure is uniform, and even if this material is subjected to permanganic acid treatment, which is a pretreatment for plating, the etching rate is equal and the overall thickness is uniform. Unevenness is difficult to obtain just by reducing.

  Therefore, it is possible to add non-uniformity to the material by blending materials that are easily or chemically difficult to process than the base materials. Often becomes opaque. For this reason, in applications where extreme transparency is required, it is currently impossible to make a material that can achieve both transparency and adhesion. In addition, when an opaque material having a plating property is bonded, there also arises a problem that light cannot be coupled between the light emitting element or the light receiving element mounted on the electric circuit and the optical waveguide.

  As another method of combining the optical waveguide and the electric circuit, there is a method of attaching a printed wiring board on the optical waveguide via an adhesive layer (see, for example, Patent Document 1). However, in such a method, since the optical circuit and the electric circuit are separately manufactured and then pasted, the positional accuracy of the electric circuit and the waveguide is deteriorated. As a result, it is impossible to mount the light emitting / receiving element reliably, and the yield of the light receiving / emitting element may be deteriorated.

  Moreover, since the printed wiring board is usually opaque, it is necessary to open it in advance before pasting. However, since the adhesive layer wraps around the opening and irregularities are generated on the surface of the printed wiring board, the coupling efficiency may be reduced. Furthermore, since the printed wiring board has a relatively thick structure, the distance between the light emitting / receiving element and the waveguide is increased by the thickness and the adhesive layer, and the coupling loss may be increased.

  Further, as a method of combining the optical waveguide and the electric circuit, there is a method in which a core and a clad are sequentially formed on a copper foil with a clad resin and attached to a substrate (for example, see Patent Documents 2 and 3). However, in such a method, since the core is formed by photolithography, UV light passes through the clad and is irregularly reflected by the copper foil having irregularities, so that the core side wall is roughened, and the waveguide loss is reduced. It may get worse. In addition, there may be a problem that it is difficult to align the positions of the optical waveguide and the electric circuit.

JP 2003-344684 A JP-A-2005-300930 JP 2006-39231 A

  The present invention has been made in view of the above-described problems of the prior art, and the object thereof is to make it possible to combine an optical waveguide and an electric circuit with high adhesion, and to reduce the coupling loss between the light emitting / receiving element and the optical circuit and the loss of the optical waveguide It aims at providing the manufacturing method of an electrical composite wiring board.

  In the method of manufacturing an optoelectric composite wiring board according to the present invention, a core forming step of forming a core on a first cladding layer formed on a substrate, and embedding the core formed on the first cladding layer. A second clad material layer laminating step of laminating a second clad material layer containing an uncured resin composition, and a metal base material layer having at least one surface roughened on the second clad material layer Forming a metal base layer, curing a non-cured resin composition of the second clad material layer to form a second clad layer, and forming an electric circuit on the metal base layer And a circuit forming step.

  According to such a configuration, since the metal substrate having a roughened surface is laminated on the uncured resin, the resin is sufficiently filled in the uneven portions of the metal surface, and the resin after being cured. And excellent adhesion between the metal and the metal. Further, a second clad material layer containing an uncured resin composition is formed so as to embed a core formed on the first clad, a metal material layer is laminated, and the uncured resin composition is further cured. Therefore, it is possible to form the optical waveguide and the metal film at the same time. Further, the metal film can be formed without increasing the number of optical waveguide forming steps. Furthermore, since the laminating method is used when laminating the uncured resin, build-up is possible, so that productivity is also excellent.

  The surface roughness Rz of the metal substrate is preferably 0.5 μm or more and 5 μm or less.

  The resin composition is preferably a dry film.

  The photoelectric composite wiring board according to the present invention is obtained by the method for manufacturing an optical composite wiring board.

  According to the present invention, an optical waveguide and an electric circuit can be combined with high adhesion, and a method for manufacturing a photoelectric composite wiring board without coupling loss between a light emitting / receiving element and an optical circuit and without loss of the optical waveguide can be provided. .

It is the schematic for demonstrating the manufacturing method of the photoelectric composite wiring board which concerns on this invention.

  Hereinafter, although the embodiment concerning the present invention is described, the present invention is not limited to these.

  In the method of manufacturing an optoelectric composite wiring board according to the present invention, a core forming step of forming a core on a first cladding layer formed on a substrate, and embedding the core formed on the first cladding layer. A second clad material layer laminating step of laminating a second clad material layer containing an uncured resin composition, and a metal base material layer having at least one surface roughened on the second clad material layer Forming a metal base layer, curing a non-cured resin composition of the second clad material layer to form a second clad layer, and forming an electric circuit on the metal base layer A method of manufacturing a photoelectric composite wiring board, comprising: a circuit forming step.

  FIG. 1 is a schematic view for explaining a method for manufacturing an optoelectric composite wiring board according to the first embodiment of the present invention. Fig.1 (a) is a schematic sectional drawing for demonstrating a core formation process. FIG.1 (b) is a schematic sectional drawing for demonstrating formation of an inclined surface. FIG. 1C is a schematic diagram for explaining the core formed in the first cladding layer. FIG.1 (d) is the schematic sectional drawing seen from the cut surface line dd of the laminated body shown in FIG.1 (c). FIG. 1E is a schematic view for explaining the second cladding material layer lamination step. FIG.1 (f) is the schematic for demonstrating a metal base material layer formation process. FIG.1 (g) is the schematic for demonstrating an electric circuit formation process.

<Core formation process>
An optical waveguide as shown in FIG. The optical waveguide propagates and outputs the input guided light by totally reflecting it at the interface between the core 13 and the second cladding layer 12 having different refractive indexes, and an optical circuit is provided by this optical waveguide. .

  Specifically, the core 13 is formed on the first cladding layer 12 of the substrate 11 having the first cladding layer 12.

  First, the first cladding layer 12 is formed on the surface of the substrate 11. As the substrate 11, various organic substrates and inorganic substrates are used without particular limitation. Specific examples of the organic substrate include an epoxy substrate, an acrylic substrate, a polycarbonate substrate, and a polyimide substrate. Examples of the inorganic substrate include a silicon substrate and a glass substrate. Further, it may be a printed circuit board in which a circuit is previously formed on the board.

  As a method of forming the first cladding layer 12, after bonding a resin film made of a curable resin material having a predetermined refractive index for forming the first cladding layer 12 on the surface of the substrate 11, A method of curing, a method of curing after applying a liquid curable resin material for forming the first cladding layer 12, and a varnish of a curable resin material for forming the first cladding layer 12 The method of hardening after apply | coating etc. is mentioned. When forming the first cladding layer 12, it is preferable to perform plasma treatment or the like on the surface of the substrate 11 in advance in order to improve adhesion.

  For example, the following method is used as a specific method of curing after the resin film is bonded to form the first cladding layer 12. First, a resin film made of a curable resin is placed on the surface of the substrate 11 so as to overlap, and then bonded by a heating press, or a resin film made of a curable resin is attached to the surface of the substrate 11 with a transparent adhesive. Paste together. And it hardens | cures by irradiating light to the bonded resin film, or heating.

  In addition, as a specific method of curing after applying a liquid curable resin material or a varnish of the curable resin material for forming the first cladding layer 12, for example, the following method is used. Is used. First, a liquid curable resin material or a varnish of a curable resin material is applied to the surface of the substrate 11 using a spin coating method, a bar coating method, a dip coating method, or the like. Then, the applied liquid curable resin material or varnish of the curable resin material is cured by irradiating light or heating.

  As the curable resin material for forming the first clad layer 12, a material having a lower refractive index at the transmission wavelength of the guided light than the material of the core 13 to be formed later is used. Examples of the refractive index at the transmission wavelength include those of about 1.5 to 1.55. Examples of such curable resin materials include epoxy resins, acrylic resins, polycarbonate resins, polyimide resins, and the like having the above-described refractive index.

  The thickness of the first cladding layer 12 is not particularly limited, but is preferably about 5 to 15 μm, for example.

  Next, a core made of a photosensitive material is formed on the outer surface of the formed first cladding layer 12.

  Here, the photosensitive material is a material in which the solubility of a portion irradiated with energy rays with respect to a liquid used in development described later changes. Specifically, for example, a material that is difficult to dissolve in a liquid used in development described later before irradiation with energy rays, but is easily dissolved after irradiation with energy rays can be used. As another example, there is a material that easily dissolves in a liquid used in development described later before irradiation with energy rays, but is difficult to dissolve after irradiation with energy rays. Specific examples of the photosensitive material include a photosensitive polymer material.

  The energy beam is not particularly limited as long as the solubility can be changed. Specifically, ultraviolet rays are preferably used from the viewpoint of ease of handling. As the photosensitive material, generally, a photosensitive polymer material whose solubility changes in a portion irradiated with ultraviolet rays is preferably used. More specifically, a photosensitive polymer material that is hard to dissolve in a liquid used in development described later is preferably used by curing the portion irradiated with ultraviolet rays.

  The core is formed by bonding a resin film (photosensitive film) made of a photosensitive polymer material having a predetermined refractive index for forming the core to the outer surface of the first cladding layer 12. In addition, a method of applying a liquid photosensitive polymer material for forming the core, a method of applying a photosensitive polymer material varnish for forming the core 13 and then drying the varnish may be used. In addition, when the core is formed, it is preferable to perform a plasma treatment or the like in advance in order to activate the outer surface of the first cladding layer 12 and improve the adhesion.

  The resin film (photosensitive film) made of the photosensitive polymer material is preferably a dry film obtained by applying a semi-cured photosensitive polymer material to a polyethylene terephthalate (PET) film or the like. By using a dry film, the handleability is improved, and entrainment of bubbles can be prevented when laminating the core. Such a dry film is usually protected by a protective film.

  As the photosensitive polymer material for forming the core, a material having a higher refractive index at the transmission wavelength of the guided light than the material of the first cladding layer 12 is used. Examples of the refractive index at the transmission wavelength include about 1.55 to 1.6.

  As a kind of the photosensitive polymer material for forming the core, a photosensitive material having an epoxy resin, an acrylic resin, a polycarbonate resin, a polyimide resin, or the like having a refractive index as described above as a resin component. Is mentioned. Of these, bisphenol-type epoxy resins are particularly preferred, and as a photosensitive polymer material for forming the core, a resin composition containing a bisphenol-type epoxy resin and a photocationic curing agent has a high heat resistance. Since a waveguide is obtained, it is preferable because it can be combined with a printed circuit board or the like. From the viewpoint of adhesion between the core and the first cladding layer 12, the photosensitive polymer material for forming the core is the same as the curable resin material for forming the first cladding layer 12. It is preferable that it is a system | strain.

  Although the thickness of the said core is not specifically limited, For example, it is preferable that it is about 20-100 micrometers.

  Specific methods for forming the core include, for example, a method of bonding a resin film to form the core, a liquid curable resin material, or a curable resin material for forming the core. The method of apply | coating this varnish is used.

  As a specific method of laminating the resin film to form the core, for example, after placing the resin film made of a curable resin on the outer surface of the first cladding layer 12, A resin film made of a curable resin is bonded to the outer surface of the first cladding layer 12 with a transparent adhesive.

  Further, as a specific method of applying a liquid curable resin material for forming the core or a varnish of the curable resin material, a liquid curable resin is applied to the outer surface of the first cladding layer 12. A varnish of a resin material or a curable resin material is applied using a spin coating method, a bar coating method, a dip coating method, or the like, and then dried as necessary.

  Before the core is exposed and cured, the core may be heat treated. By doing so, irregularities, bubbles, voids, etc. on the surface of the core disappear and become smooth. The heat treatment temperature is preferably a temperature at which the unevenness, bubbles, voids and the like on the surface of the core disappear and become a smooth viscosity, and is appropriately selected depending on the type of the curable resin material forming the core. Moreover, as heat processing time, it is preferable that it is about 10 to 30 minutes from the point from which the said effect is fully acquired. The means for heat treatment is not particularly limited, and a method such as a method of treating in an oven set at a predetermined temperature or a method of heating with a hot plate is used.

  Next, the core is irradiated with exposure light through a photomask to perform pattern exposure of a predetermined shape on the core. Further, the exposure can be used without any particular limitation as long as it is a method of exposing light having a wavelength capable of deteriorating (curing, etc.) the photosensitive material with light with a necessary amount of light. Specifically, for example, a method of using energy rays such as ultraviolet rays as the exposure light may be used. In view of ease of handling, ultraviolet rays are preferably used. In addition, contact exposure that exposes a photomask placed so as to be in contact with the surface of the core, projection exposure that exposes in a state where a predetermined interval is maintained so as not to contact the outer surface of the core, etc. Any exposure method may be used.

The exposure conditions are appropriately selected according to the type of photosensitive material. For example, the exposure light may be exposed to 500 to 3500 mJ / cm ² using a high-pressure mercury lamp as the exposure light. Is selected.

  Further, after the exposure, post-curing with heat is also effective from the viewpoint of ensuring curing. As post-curing conditions, a temperature of about 80 to 160 ° C. and a time of about 20 to 120 minutes are preferable.

  Next, development processing is performed. In the development process, when the core photosensitive material is a positive type, an unexposed portion is removed, and when the core is a negative type, an unnecessary portion is removed by washing away the exposed portion with a developer. It is a process. Examples of the developer include acetone, isopropyl alcohol, toluene, ethylene glycol, or a mixture of these at a predetermined ratio. Furthermore, for example, an aqueous developer as disclosed in JP-A-2007-292964 can be preferably used. Examples of the developing method include a method of spraying a developer by spraying and a method using ultrasonic cleaning.

  As described above, the core 13 is formed on the first cladding layer 12.

  Next, an inclined surface 15 a for reflecting light is formed on the core 13. The method is not particularly limited as long as an inclined surface described later can be formed. Here, the inclined surface refers to the light incident from the opposite side of the core 13 that is in contact with the first cladding layer 12 into the core 13 or the light emitted from the core 13 as the first cladding layer. 12 is an inclined surface for reflecting light so as to be led out to the side opposite to the side in contact with 12. Specific methods for forming the inclined surface include, for example, a method of cutting with a dicing blade, a method by laser ablation, and the like. More specifically, for example, the following methods can be mentioned.

  As shown in FIG. 1B, one surface of the blade edge is a surface parallel to the surface direction of the blade, and the other surface is a surface whose angle with respect to the surface direction of the blade is a predetermined angle, for example, 45 °. Using the blade 14, the core 13 is cut to form the recess 15. That is, the blade 14 is suspended from the core 13 while being rotated so as to be substantially perpendicular to the core 13. At that time, the concave portion 15 guides the light incident from the opposite side of the first cladding layer 12 into the core 13 or guides the light emitted from the core 13 to the opposite side of the first cladding layer 12. The core 13 is cut so as to form the recess 15 having the inclined surface 15a for reflecting the light. In addition, the recess 15 is formed with an inclined surface 15 a so that the cross-sectional area parallel to the first cladding layer 12 gradually decreases as the first cladding layer 12 is approached. In addition, the blade 14 is a disk-shaped rotary blade, and a blade having a cutting edge in the circumferential portion, for example, a dicing blade or the like is used. Moreover, the shape of the recessed part 15 will not be specifically limited if the inclined surface 15a is formed, For example, groove shape etc. are mentioned.

  When cutting the core 13 with the blade 14, if necessary, the core 13 may be cut while being softened by heating the substrate 11, the blade 14, or the like. Further, the blade 14 may be cut so that the blade edge reaches the first cladding layer 12 or not.

In addition, the mirror part which consists of a metal layer can also be formed on the inclined surface 15a. The method for forming the mirror part is not particularly limited as long as the metal base material 16 is laminated on the inclined surface 15a. Specifically, the following method is mentioned, for example. First, a resist is applied to the inclined surface 15a. Thereafter, UV irradiation is performed through a photomask or the like so that only the resist on the inclined surface 15a is not removed by the development process. Then, development processing is performed to leave only the resist on the inclined surface 15a. Then, after performing an etching process, the resist is peeled off. By doing so, the mirror part 16a which consists of a metal layer can be formed on the inclined surface 15a.
Further, when the mirror portion 16a is formed by such a method, the mounting accuracy of the obtained photoelectric composite wiring board, such as a light receiving element and a light emitting element, becomes excellent.

  Through the steps as described above, an optical waveguide as shown in the lower part of FIG. The formed optical waveguide is formed by the core 13 and the first cladding layer 12, and the core 13 has a refractive index higher than that of the first cladding layer 12, and the light propagating through the core is reflected by total reflection. It can be confined inside. Such an optical waveguide is mainly formed as a multimode waveguide. The size of the core 13 of the optical waveguide is, for example, a rectangular shape of 20 to 100 μm, the thickness of the first cladding layer 12 is 5 to 15 μm, respectively, and the refractive index difference between the core and the first cladding layer is 0.5 to 3 % Is suitable, but not limited to this.

<Second clad material layer lamination step>
In the second clad material layer laminating step in the manufacturing method of the present invention, as shown in FIG. 1 (e), the second clad material layer 17 laminated on the above-mentioned metal base material is further provided so as to embed the core 13. It is formed by stacking.

  As a method of laminating the second clad material layer 17, a method in which the second clad material layer 17 laminated on the metal equipment is bonded so as to embed the core 13 and then cured by light, heat, or the like. Is mentioned.

  The curable resin material for forming the second cladding material layer 17 is not particularly limited as long as it is a curable resin material having a lower refractive index at the transmission wavelength of the guided light than the material of the core 13. Usually, the same kind of curable resin material as that used to form the first cladding layer 12 is used.

  As the curable resin, a resin having a lower refractive index at the transmission wavelength of the guided light than the material of the core 13 to be formed later is used. Examples of the refractive index at the transmission wavelength include those of about 1.5 to 1.55.

<Metal base material layer formation process>
Next, as shown in FIG. 1B, a metal base layer 16 having a roughened surface on at least one side is formed on the above-described cladding layer.

  It does not specifically limit as a method to form the metal base material 16, A well-known method can be used. Specifically, for example, a vapor deposition method such as a vacuum vapor deposition method, a sputtering method, a nano paste method, and the like can be given.

  As the metal substrate 16, a copper foil, an aluminum foil, a tungsten foil, an iron foil, or the like can be used, and it is particularly preferable to use a copper foil.

  Moreover, the said copper foil can select the copper foil according to required characteristics, such as a film thickness, surface roughness, and surface treatment.

  The metal substrate 16 needs to have at least one surface roughened. The method for roughening the surface of the metal substrate 16 can be performed by an appropriate method, and examples thereof include an etching process and a surface oxidation process. By performing the treatment, the anchor effect of the metal substrate 16 can be obtained, and the adhesion of the second cladding layer containing the above-described resin composition is improved.

  Moreover, what formed the barrier layer with zinc other than copper, nickel, etc. can also be used. Moreover, you may use what formed the antirust layer by the chromate process. Furthermore, it is also possible to use what formed the process by the silane coupling process in order to improve adhesiveness.

  The surface roughness Rz of the metal substrate 16 is preferably 0.5 μm or more and 5 μm or less, and more preferably 1 μm or more and 3 μm or less from the viewpoint of adhesion and patterning properties. When the surface roughness Rz is less than 0.5 μm, the anchor effect of the metal substrate is difficult to be obtained, so that the adhesion with the resin composition is lowered. On the other hand, if it is larger than 5 μm, it becomes difficult to obtain a fine pattern of the metal substrate.

  The thickness of the metal substrate 16 is preferably 3 μm or more and 50 μm or less, and more preferably 5 μm or more and 20 μm or less from the viewpoint of patterning properties and electrical characteristics. If the thickness of the metal base material 16 is less than 3 μm, the base material becomes difficult to handle, and a design is required in which the width must be increased in order to secure a resistance value, resulting in limitations. On the other hand, when the thickness is larger than 50 μm, time is required for metal patterning, and side etching is liable to occur, which causes a problem in quality stability.

<Curing process>
As shown in FIG. 1C, by curing the clad material layer 12, the clad material layer 12 becomes a second clad layer (upper clad layer) 13 formed so as to embed the core 13 therein.

  As a method for curing the clad material layer 12, for example, heat treatment using an oven, a hot plate, or the like is used.

  Through the steps as described above, an optical waveguide as shown in FIG. 1C is formed. The formed optical waveguide is formed by the core 13 and the clad layers (the first clad layer 12 and the second clad layer 18) covering the core 13, and the core 13 has a refractive index higher than that of the clad layer. The light that propagates inside is confined in the core by total reflection. Such an optical waveguide is mainly formed as a multimode waveguide. The size of the core 13 of the optical waveguide is, for example, a rectangular shape of 20 to 100 μm, and the thickness of the lower first cladding layer 12 and the upper second cladding layer 18 excluding the thickness of the layer including the core portion is 5 respectively. The refractive index difference between the core part and the clad layer is suitably about 0.5 to 3%, but is not limited thereto.

<Electric circuit formation process>
The electric circuit forming step is a step of forming an electric circuit 16a on the formed metal base 16 as shown in FIG. The electric circuit 16a can be formed by, for example, a well-known etching technique for forming a circuit. Here, the boundary surface between the first cladding layer 12 and the electric circuit 16a is a rough surface, and the anchor effect is obtained by the unevenness (rough surface) formed in the electric circuit 16a. It is formed on the top with good adhesion. As described above, the photoelectric composite wiring board 19 including the optical circuit and the electric circuit 16a is obtained by this electric circuit forming step.

  As the electrical circuit formation processing, for example, through-hole processing, gold plating processing, or the like can be used in addition to the above-described etching processing. The alignment of the optical circuit and the electric circuit can be performed by using, for example, markings provided on the outer shape reference, the side surface of the substrate, or the back surface of the substrate.

  The formed photoelectric composite wiring board 19 is formed by the core 13 and the cladding layers (the first cladding layer 12 and the second cladding layer 18) in which the core 13 is embedded, and the core 13 is a cladding layer. The refractive index is higher than that, and light propagating inside is confined in the core by total reflection. Such an optical waveguide is mainly formed as a multimode waveguide. The size of the core 13 of the electric composite wiring board 19 is, for example, a rectangular shape of 20 to 100 μm, and the thickness of the lower first cladding layer 12 and the upper second cladding layer 12 excluding the thickness of the layer including the core is Each of 5 to 15 μm and the refractive index difference between the core and the clad layer are suitably about 0.5 to 3%, but are not limited thereto. In addition, the photoelectric composite wiring board 19 can be formed by forming the electric circuit 16 a using the metal substrate 16 on the second cladding layer 18.

  Hereinafter, the present invention will be described more specifically with reference to examples. The scope of the present invention is not limited by the examples.

Example 1
First, the photoelectric composite wiring board in the manufacturing method of the present invention is manufactured.

<Manufacture of photoelectric composite wiring board>
Prior to manufacturing the optoelectric composite wiring board, a first curable film for cladding, a curable film for core, and a second resin film for cladding were prepared.

[Curable film for first cladding]
62 parts by mass of solid epoxy adduct (“EHPE3150” manufactured by Daicel Chemical Industries, Ltd.), 18 parts by mass of phenoxy resin (“YP50” manufactured by Tohto Kasei Co., Ltd.), trimethylolpropane type epoxy resin (“Epototo” manufactured by Toto Kasei Co., Ltd.) YH300 ") 8 parts by mass, 12 parts by mass of liquid bisphenol A type epoxy resin (" Epiclon 850S "manufactured by DIC), 0.5 parts by mass of photocationic curing agent (" SP-170 "manufactured by Adeka), heat 0.5 parts by mass of a cationic curing agent (“SI-150L” manufactured by Sanshin Chemical Industry Co., Ltd.) and 0.1 parts by mass of a surface conditioner (“F470” manufactured by DIC), 30 parts by mass of toluene and methyl ethyl ketone It is dissolved in a mixed solvent of 70 parts by mass, filtered through a membrane filter having a pore size of 1 μm, and then degassed under reduced pressure, whereby the clad epoxy resin composition is cooled. The scan was prepared. After applying this varnish on a PET film (“A4100” manufactured by Toyobo Co., Ltd.) using a multi-coater of a comma coater head manufactured by Hirano Techseed Co., Ltd., the solvent was removed and dried to obtain a thickness of 10 μm. A curable film for cladding was prepared.

  Further, a curable film for cladding having a thickness of 50 μm was prepared by changing the coating thickness of the varnish on the PET film. “OPP-MA420” manufactured by Oji Specialty Paper Co., Ltd. was thermally laminated as a protective film on the produced film.

[Curable film for core]
8 parts by mass of liquid 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate (“Celoxide 2021P” manufactured by Daicel Chemical Industries, Ltd.), solid epoxy adduct (“Daicel Chemical Industries, Ltd. EHPE3150 ") 12 parts by mass, solid bisphenol A type epoxy resin (" Epicoat 1006FS "manufactured by Japan Epoxy Resin) 37 parts by mass, trifunctional epoxy resin (" VG-3101 "manufactured by Mitsui Chemicals) 15 parts by mass , 18 parts by mass of a solid novolac type epoxy resin (“EPPN201” manufactured by Nippon Kayaku Co., Ltd.), 10 parts by mass of a liquid bisphenol A type epoxy resin (“Epiclon 850S” manufactured by DIC), a photocationic curing agent (manufactured by Adeka) "SP-170") 0.5 parts by mass, thermal cationic curing agent ("SI made by Sanshin Chemical Industry Co., Ltd." 150 L ") 0.5 parts by mass and 0.1 part by mass of a surface conditioner (" F470 "manufactured by DIC) were dissolved in a mixed solvent of 30 parts by mass of toluene and 70 parts by mass of methyl ethyl ketone, and the pore diameter was 1 µm. After filtering with a membrane filter, the varnish of the core epoxy resin composition was prepared by defoaming under reduced pressure.

  After applying this varnish on a PET film (“A4100” manufactured by Toyobo Co., Ltd.) using a multi-coater of a comma coater head manufactured by Hirano Techseed Co., the thickness was 40 μm by removing the solvent and drying. A core curable film was prepared. “OPP-MA420” manufactured by Oji Specialty Paper Co., Ltd. was thermally laminated as a protective film on the produced film.

[Resin film for second cladding material]
62 parts by mass of solid epoxy adduct (“EHPE3150” manufactured by Daicel Chemical Industries, Ltd.), 18 parts by mass of phenoxy resin (“YP50” manufactured by Tohto Kasei Co., Ltd.), trimethylolpropane type epoxy resin (“Epototo” manufactured by Toto Kasei Co., Ltd.) YH300 ") 8 parts by mass, liquid bisphenol A type epoxy resin (" Epiclon 850S "manufactured by DIC) 12 parts by mass, thermal cationic curing agent (" SI-150L "manufactured by Sanshin Chemical Industry Co., Ltd.) 1.0 mass And 0.1 part by mass of a surface conditioner (“F470” manufactured by DIC) were dissolved in a mixed solvent of 30 parts by mass of toluene and 70 parts by mass of methyl ethyl ketone, and filtered through a membrane filter having a pore size of 1 μm. The varnish of the epoxy resin composition for resin layers was prepared by degassing under reduced pressure. After applying this varnish on a PET film (“A4100” manufactured by Toyobo Co., Ltd.) using a multi-coater of a comma coater head manufactured by Hirano Techseed Co., Ltd., the solvent was removed and dried to obtain a thickness of 20 μm. A curable film for a resin layer was prepared.

[Fabrication of optical waveguide]
First, copper on both sides of R1766 manufactured by Panasonic Electric Works Co., Ltd. was removed by etching. This etched off was used as a substrate. On the surface of this substrate, the resin film for a first cladding layer having a thickness of 10 μm produced by the method described above was laminated using a vacuum laminator (V-130) under the conditions of 60 ° C. and 0.2 MPa. And the ultraviolet light was irradiated to the resin film for 1st clad layers on the conditions of ² J / cm < ² > using the ultrahigh pressure mercury lamp. Thereafter, the release film of the resin film for the first cladding layer was peeled off. Thereafter, heat treatment was performed at 150 ° C. for 30 minutes, and oxygen plasma treatment was further performed. By doing so, the 1st clad layer (lower clad layer) which the resin film for the 1st clad layers hardened was formed on the substrate.

Next, on the surface of the first cladding layer, the resin film for the core part having a thickness of 40 μm manufactured by the above-described method was laminated using a vacuum laminator (V-130) under the conditions of 60 ° C. and 0.2 MPa. .
And the negative mask which formed the slit of the linear pattern of width 40micrometer and length 120mm was mounted in the surface of the resin film for core parts. Thereafter, ultraviolet light was irradiated with an amount of light of 3 J / cm ² with an ultra-high pressure mercury lamp adjusted so that the irradiation light became substantially parallel light, and the portion corresponding to the slit of the core portion resin film was photocured.

  Next, the release film of the core portion resin film was peeled off. Thereafter, heat treatment was performed at 140 ° C. for 2 minutes. And it developed using the aqueous | water-based flux cleaning agent (Arakawa Chemical Co., Ltd. make Pine Alpha ST-100SX) adjusted to 55 degreeC as a developing solution. By doing so, the unexposed part of the core part resin film is dissolved and removed. Further, after finishing and washing with water, air blowing was performed. Then, it was dried at 100 ° C. for 10 minutes. By doing so, the core part as shown to Fig.1 (a) was formed.

  Next, as shown in FIG. 1B, one surface of the blade edge is a surface parallel to the surface direction of the blade, and the other surface has an angle (vertical angle) of 45 ° with respect to the surface direction of the blade. Using a blade that is a surface (dicing blade manufactured by DISCO Corporation (particle size: No. 5000)), the position of 10 mm from both ends of the core portion is set to 2 at a rotational speed of 10000 rpm and a moving speed of 0.1 mm / second. I cut it. By doing so, as shown in FIG.1 (b), the recessed part which has a 45 degree inclined surface was formed so that a core part might be cut | disconnected completely.

Next, a solution obtained by diluting the resin varnish used for manufacturing the first clad layer resin film 50 times with a mixed solvent obtained by mixing toluene and MEK at a mass ratio of 3: 7 is 45 °. A thin brush was applied to the inclined surface. Then, after drying at 100 degreeC for 30 minutes, it exposed by irradiating an ultraviolet light on the conditions of 1 J / cm < ² > with the ultrahigh pressure mercury lamp. Thereafter, heat treatment was further performed at 120 ° C. for 10 minutes. By doing so, the 45 ° inclined surface was smoothed.
Next, a swelling process, a permanganate treatment process, and a reduction treatment process were performed on the core part and the lower clad layer. By doing so, the surface of the core part and the lower clad layer was etched, and irregularities were formed on the surface.

[Second clad material layer lamination step]
Next, as shown in FIG. 1 (e), a second clad material laminated metal substrate having a thickness of 50 μm manufactured by the above-described method so as to cover the lower clad layer and the core portion is formed into a pressure-type vacuum laminator. (“V-130” manufactured by Nichigo Morton Co., Ltd.) was used for lamination under the conditions of 80 ° C. and 0.3 MPa. Thereafter, the PET film of the second clad layer resin film was peeled off. By doing so, a second cladding layer (upper cladding layer) was formed so as to cover the first cladding layer and the core portion. The second cladding layer only needs to cover the core portion and the first cladding layer around the core portion.

[Metal substrate layer forming step]
Next, a roughened surface of a copper foil (“F2-WS” manufactured by Furukawa Electric Co., Ltd.) having a surface roughness Rz of 2.7 μm and a thickness of 12 μm is applied to the cladding side under the same conditions as the above-mentioned laminate. And laminated on the optical waveguide (see FIG. 1 (f)).

[Curing process]
By performing heat treatment at 150 ° C. for 30 minutes, the second cladding layer 18 in which the second cladding material layer was cured was formed.

[Electric circuit formation process]
The formed metal base material 16 is formed on the electric circuit 16a having a predetermined pattern by an etching technique, and after further forming a solder resist, gold plating treatment and silk printing are performed, so that an optical circuit (optical waveguide) and the electric circuit 16a The photoelectric composite wiring board 19 provided with (refer FIG.1 (g)) was obtained. The peel strength of this metal layer was 0.6 N / m, which was a practical level.

(Comparative Example 1)
The clad material was cured on the substrate, and electroless plating and electrolytic plating were performed thereon to form a 12 μm copper foil. The surface roughness Rz was measured to be 0.1 μm. This copper foil was peeled from the substrate. An opto-electric composite wiring board was prepared in the same manner as in Example 1 except that the second clad material layer formed on the copper foil with a bar coater to a thickness of 50 μm was used.

<Evaluation of loss of photoelectric composite wiring board>
The loss evaluation of the photoelectric composite wiring board 19 obtained in Example 1 was performed. That is, light (850 nm wavelength) from a VCSEL (Vertical Cavity Surface Emitting Laser), which is a light emitting / receiving element, passes through an optical fiber having a core diameter of 10 μm and NA of 0.21 to one of optical waveguides (optical circuits) of the photoelectric composite wiring board 19. The power of the light (P1) that is incident on the mirror surface 10 through the matching oil (silicone oil) and emitted from the other mirror surface 10 through the optical fiber having the core diameter of 200 μm and NA 0.4 through the same matching oil. ) Was measured with a power meter. Further, the power (P0) of the light emitted without inserting the second cladding layer 15 and the optical waveguide of the photoelectric composite wiring board 19 by directly abutting the end portions of the two optical fibers is measured with a power meter. did. Then, the insertion loss of the photoelectric composite wiring board 19 was obtained from the calculation formula of “(−10) log (P1 / P0)”, which was as small as 2.1 dB, which was a practical level.

  On the other hand, the peel strength of the copper foil in the photoelectric composite wiring board obtained in Comparative Example 1 was 0.1 N / m, which was less than the practical level. This is presumably because the surface roughness Rz of the metal substrate used was smaller than 0.5 μm.

  As described above in detail with reference to specific examples, the second cladding is formed by laminating the second cladding material layer 17 containing the uncured resin composition so as to embed the core formed on the first cladding layer 12. A layer forming step, a metal substrate layer forming step of forming a metal substrate layer 16 having at least one surface roughened on the second cladding material layer, and uncuring of the second cladding material layer 17 The outer surface of the metal substrate 16 is provided with a curing step of curing the resin composition to form the second cladding layer 18 and an electric circuit forming step of forming an electric circuit on the metal substrate layer 16. Asperities (rough surfaces) exist on the surface, and the adhesion of the electric circuit 16a is improved. Further, since the transparency of the second cladding layer 15 is at a level that does not cause a problem in practice, the coupling loss between the light emitting / receiving element such as a VCSEL on the electric circuit 16a and the optical waveguide is suppressed.

  In addition, since the metal base 16 is built up on the optical waveguide that has already been completed, the side wall of the core 13 is not roughened, and the waveguide loss of the optical waveguide is suppressed. In addition, the optical circuit and the electric circuit 16a are separately manufactured, and the optical waveguide is manufactured by build-up on the substrate 16 instead of a manufacturing method in which the optical circuit and the electric circuit 16a are bonded to each other later. Since this is a manufacturing method in which the electric circuit 16a is combined, the photoelectric composite wiring board 19 can be obtained with a good yield.

  Moreover, when laminating | stacking the resin composition film (2nd clad layer film) containing an epoxy resin at the 2nd clad layer formation process, it is the vacuum conventionally used for manufacture of a printed wiring board, or manufacture of an optical waveguide. Since it can respond to facilities with a mass production record such as a laminator, the productivity of the metal-clad laminate and the photoelectric composite wiring board 19 is improved.

  Further, since the second clad layer 18 contains a solid epoxy resin and a liquid epoxy resin as the epoxy resin, the properties of the resin composition are diversified, and desired properties (including refractive index) are obtained by combining the epoxy resin components. ) Resin composition can be obtained.

11 substrate 12 first cladding layer 13 core 14 blade (dicing blade)
DESCRIPTION OF SYMBOLS 15 Recessed part 15a Inclined surface 16 Metal layer 16a Mirror part 17 2nd clad material layer 18 2nd clad layer 19 Opto-electric composite wiring board

Claims (4)

A core forming step of forming a core on a first cladding layer formed on the substrate;
A second clad material layer laminating step of laminating a second clad material layer containing an uncured resin composition so as to embed a core formed on the first clad layer;
A metal substrate layer forming step of forming a metal substrate layer having a roughened surface on at least one side on the second cladding material layer;
A curing step of curing the uncured resin composition of the second cladding material layer to form a second cladding layer;
And an electric circuit forming step of forming an electric circuit on the metal substrate layer.   The surface roughness Rz of the said metal base material is 0.5 micrometer or more and 5 micrometers or less, The manufacturing method of the photoelectric composite wiring board of Claim 1 characterized by the above-mentioned.   The method for producing an optoelectric composite wiring board according to claim 1, wherein the resin composition is a dry film.   An opto-electric composite wiring board obtained by the method for manufacturing an opto-electric composite wiring board according to claim 1.

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