JP5583467B2 - Metal-clad laminate, photoelectric composite wiring board, method for producing metal-clad laminate, and method for producing photoelectric composite wiring board - Google Patents

Description

  The present invention belongs to the technical field of a photoelectric composite wiring board provided with an optical circuit and an electric circuit.

  In order to solve the problems of high-frequency noise and transmission band shortage accompanying signal speedup in various information processing devices in recent years, a photoelectric composite wiring board, which is a printed board with a built-in optical waveguide, has attracted attention. In such an optical composite wiring board, the optical waveguide propagates by totally reflecting the guided light input to the mirror surface at one end at the interface between the core and the clad having different refractive indexes, and outputs it from the mirror surface at the other end. The optical circuit is provided by this optical waveguide.

  2. Description of the Related Art Conventionally, as a method of manufacturing a photoelectric composite wiring board by combining an optical waveguide and an electric circuit, a method of forming an electric circuit by performing metal plating directly on the optical waveguide is known. However, for the following reason, there is a problem that the electric circuit is easily peeled off because the adhesion of the metal plating to the transparent resin constituting the clad of the optical waveguide is low.

  That is, in order to form metal plating with good adhesion on the optical waveguide, it is proposed to form fine irregularities on the outer surface of the clad of the optical waveguide so as to obtain an anchor effect. Such irregularities can be formed by, for example, an etching process that is a pretreatment of metal plating. However, the cladding of the optical waveguide is made of a transparent resin having a uniform structure so that high transparency can be obtained. Since such a transparent resin has a uniform structure, the etching rate is generally the same. Therefore, even if the etching process is performed, the thickness of the clad is reduced uniformly as a whole, and unevenness is hardly formed. Therefore, it is conceivable to make the structure of the transparent resin non-uniform so that irregularities are formed on the outer surface of the clad by etching. However, if the structure of the transparent resin is not uniform, the transparency of the cladding is lowered, and it may be difficult to couple light between the light emitting / receiving element on the electric circuit and the optical waveguide. In other words, the high transparency of the clad and the good adhesion of the metal plating are not compatible, and as a result, the anchor effect is sacrificed to maintain the high transparency of the clad, and the transparent resin constituting the clad is not affected. There is a problem that the adhesion of the metal plating is lowered, so that the electric circuit is easily peeled off.

  Patent Document 1 discloses an epoxy resin composition containing an epoxy resin and rubber particles. However, this epoxy resin composition is for an insulating layer of a normal multilayer printed wiring board and not for a photoelectric composite wiring board. Therefore, even if an insulating layer of a normal multilayer printed wiring board is produced using the epoxy resin composition disclosed in Patent Document 1, high transparency of the clad and good adhesion of the electric circuit in the photoelectric composite wiring board Does not lead to the solution of the above-mentioned problem of being incompatible.

JP 2007-254709 A (paragraphs 0011 and 0012)

  An object of the present invention is to provide a photoelectric composite wiring board in which the adhesion of an electric circuit is enhanced and the coupling loss between the light emitting / receiving element and the optical waveguide is suppressed.

  One aspect of the present invention includes an optical waveguide having a core and a clad surrounding the core, a resin layer laminated on the optical waveguide, and a metal layer laminated on the resin layer, The resin layer contains an epoxy resin and rubber particles composed of a transparent resin of a different type from the epoxy resin, and a boundary surface between the resin layer and the metal layer is a convex portion and / or rubber made of an epoxy resin. It is a metal-clad laminated board which is a rough surface in which the convex part by particle | grains was formed.

  Another aspect of the present invention includes an optical waveguide having a core and a clad surrounding the core, a resin layer laminated on the optical waveguide, and an electric circuit formed on the resin layer. The resin layer contains an epoxy resin and rubber particles composed of a transparent resin of a different type from the epoxy resin, and a boundary surface between the resin layer and the electric circuit has a convex portion and / or an epoxy resin. Or it is the photoelectric composite wiring board which is a rough surface in which the convex part by a rubber particle was formed.

  In the present invention, the transparent resin constituting the rubber particles is preferably at least one of an acrylic monomer, a styrene monomer, a vinyl monomer, a diene monomer polymer, or a copolymer thereof.

  In this invention, it is preferable that content of the rubber particle in a resin layer is 3-30 mass parts with respect to 100 mass parts of epoxy resins.

  In the present invention, the rubber particles preferably have a particle size of 30 to 3000 nm.

  In the present invention, the resin layer preferably contains a solid epoxy resin and a liquid epoxy resin as the epoxy resin.

  In the present invention, the resin layer preferably further contains a cationic curing agent.

  Still another aspect of the present invention provides a resin layer containing an epoxy resin and rubber particles made of a transparent resin of a different type from the epoxy resin on an optical waveguide having a core and a clad surrounding the core. A metal-clad laminate comprising: a resin layer forming step of forming a metal layer; an etching process step of etching the formed resin layer; and a metal layer forming step of forming a metal layer by metal plating on the etched resin layer It is a manufacturing method of a board.

  Still another aspect of the present invention provides a resin layer containing an epoxy resin and rubber particles made of a transparent resin of a different type from the epoxy resin on an optical waveguide having a core and a clad surrounding the core. Forming a resin layer, etching a process for etching the formed resin layer, forming a metal layer on the etched resin layer by metal plating, and forming the formed metal layer And an electric circuit forming step for forming an electric circuit.

  In this invention, it is preferable to form a resin layer by laminating | stacking and hardening the film of the resin composition containing an epoxy resin and a rubber particle in a resin layer formation process.

  ADVANTAGE OF THE INVENTION According to this invention, the photoelectric composite wiring board by which the adhesiveness of the electric circuit was improved and the coupling loss of a light emitting / receiving element and an optical waveguide was suppressed is provided.

FIG. 1 is a schematic cross-sectional view for explaining a method for producing a metal-clad laminate and a photoelectric composite wiring board in an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view for explaining a method for producing a metal-clad laminate and a photoelectric composite wiring board in the examples.

  Conventionally, for example, in FTTH (Fiber To The Home) and long-distance communication and medium-distance communication in the in-vehicle field, an optical fiber has been mainly used as a transmission medium. In recent years, high-speed transmission using light has become necessary even in short-distance communication within 1 meter, typically a small terminal device such as a mobile phone. In this field, optical waveguide type that can be realized with high-density wiring (narrow pitch, branching, crossing, multilayering, etc.), surface mounting, integration with electric substrates, bending with a small curvature radius, etc. An optical wiring board is preferred. Such optical wiring boards are roughly classified into the following two types. One can be used as a replacement for PWB (Printed Wiring Board) used for printed wiring boards, and the other is FPC (Flexible Printed Circuits) used for hinges of small terminal devices. It can be used as a replacement. In any case, electrical wiring for operating a VCSEL (Vertical Cavity Surface Emitting Laser), PD (Photo Diode), or IC, which is a light emitting / receiving element, is indispensable, and transmission of a low-speed signal is also necessary. It is preferable to take the form of a photoelectric composite wiring board in which an optical circuit and an electric circuit provided by a waveguide are mixedly mounted.

  Conventionally, as a method of manufacturing a photoelectric composite wiring board by compounding an optical waveguide and an electric circuit, (i) a method of forming an electric circuit by performing metal plating directly on the optical waveguide, and (ii) an optical waveguide. (Iii) Fabricating an optical waveguide by sequentially forming a core and a clad on a copper foil coated with a clad resin on one side (copper foil with clad resin) And the method of affixing this on a board | substrate is known. However, each has the following problems.

  In the method (i), in order to form a metal plating with good adhesion on the optical waveguide, it is proposed to form fine irregularities on the outer surface of the cladding of the optical waveguide so as to obtain an anchor effect. The Such irregularities can be formed by, for example, an etching process that is a pretreatment of metal plating. However, the cladding of the optical waveguide is made of a transparent resin having a uniform structure so that high transparency can be obtained. Since such a transparent resin has a uniform structure, the etching rate is generally the same. Therefore, even if the etching process is performed, the thickness of the clad is reduced uniformly as a whole, and unevenness is hardly formed. Therefore, it is conceivable to make the structure of the transparent resin non-uniform so that irregularities are formed on the outer surface of the clad by etching. However, if the structure of the transparent resin is not uniform, the transparency of the cladding is lowered, and it may be difficult to couple light between the light emitting / receiving element on the electric circuit and the optical waveguide. In other words, the high transparency of the clad and the good adhesion of the metal plating are not compatible, and as a result, the anchor effect is sacrificed to maintain the high transparency of the clad, and the transparent resin constituting the clad is not affected. There is a problem that the adhesion of the metal plating is lowered, so that the electric circuit is easily peeled off.

  In the method (ii), since the optical circuit and the electric circuit are separately manufactured and then bonded together, there is a problem that the positional accuracy between the optical circuit and the electric circuit is lowered and the manufacturing yield is lowered. is there. In addition, the printed wiring board is pre-formed with an opening to allow light to pass through, so the adhesive wraps around the opening and protrudes non-uniformly, and light passes through the opening, causing light to diffusely reflect and reduce coupling efficiency. There is a problem of doing. Further, there is a problem that the coupling loss increases because the distance between the light emitting / receiving element on the electric circuit and the optical waveguide is increased by the thickness of the printed wiring board and the thickness of the adhesive layer.

  In the method of (iii), when a core is produced by photolithography, an ultraviolet light irradiated for photocuring the core resin passes through a clad provided on one side of the copper foil, and the copper foil is uneven. In this case, the irregularly reflected ultraviolet light causes roughness on the side wall of the core, which increases the waveguide loss.

  Thus, in the conventional method for manufacturing a photoelectric composite wiring board, the adhesion of an electric circuit is improved, the coupling loss between the light emitting / receiving element and the optical waveguide is suppressed, and the waveguide loss of the optical waveguide is suppressed. At present, composite wiring boards cannot be obtained with good yield.

  In view of the current situation, the present inventors have conducted extensive research and improvement on the manufacturing method of the photoelectric composite wiring board, and as a result, have a rubber composed of an epoxy resin and a transparent resin of a different type from the epoxy resin. When a photoelectric composite wiring board is manufactured using a resin composition containing particles, the adhesion of an electric circuit is improved, the coupling loss between the light emitting / receiving element and the optical waveguide is suppressed, and the waveguide loss of the optical waveguide is suppressed. The present invention has been completed by finding that the obtained photoelectric composite wiring board can be obtained with good yield.

  That is, in this embodiment, the optical waveguide having a core and a clad surrounding the core, a resin layer laminated on the optical waveguide, and a metal layer laminated on the resin layer, The resin layer contains an epoxy resin and rubber particles composed of a transparent resin of a different type from the epoxy resin, and a boundary surface between the resin layer and the metal layer has a convex portion and / or an epoxy resin. Provided is a metal-clad laminate that is a rough surface with protrusions formed by rubber particles.

  In this embodiment, the optical waveguide having a core and a clad surrounding the core, a resin layer laminated on the optical waveguide, and an electric circuit formed on the resin layer, The resin layer contains an epoxy resin and rubber particles made of a transparent resin of a different type from the epoxy resin, and a boundary surface between the resin layer and the electric circuit is a convex portion and / or an epoxy resin. There is provided a photoelectric composite wiring board having a rough surface on which convex portions of rubber particles are formed.

  In the present embodiment, the transparent resin constituting the rubber particles is preferably at least one of an acrylic monomer, a styrene monomer, a vinyl monomer, a diene monomer polymer, or a copolymer thereof. .

  In this embodiment, it is preferable that content of the rubber particle in a resin layer is 3-30 mass parts with respect to 100 mass parts of epoxy resins.

  In the present embodiment, the rubber particles preferably have a particle size of 30 to 3000 nm.

  In the present embodiment, the resin layer preferably contains a solid epoxy resin and a liquid epoxy resin as the epoxy resin.

  In this embodiment, it is preferable that the resin layer further contains a cationic curing agent.

  Further, in this embodiment, a resin layer containing an epoxy resin and rubber particles made of a transparent resin of a different type from the epoxy resin is formed on an optical waveguide having a core and a clad surrounding the core. A metal-clad laminate comprising: a resin layer forming step, an etching step for etching the formed resin layer, and a metal layer forming step for forming a metal layer by metal plating on the etched resin layer A manufacturing method is provided.

  Further, in this embodiment, a resin layer containing an epoxy resin and rubber particles made of a transparent resin of a different type from the epoxy resin is formed on an optical waveguide having a core and a clad surrounding the core. A resin layer forming step, an etching process step for etching the formed resin layer, a metal layer forming step for forming a metal layer on the etched resin layer by metal plating, and the formed metal layer as an electric circuit. And an electric circuit forming step to be formed.

  In the present embodiment, in the resin layer forming step, it is preferable to form a resin layer by laminating and curing a film of a resin composition containing an epoxy resin and rubber particles.

<Resin composition>
In this embodiment, the resin composition is a resin composition for photoelectric composite wiring boards. The resin composition contains an epoxy resin and rubber particles. The epoxy resin preferably contains a solid epoxy resin and a liquid epoxy resin. The rubber particles are made of a different kind of transparent resin from the epoxy resin. The resin composition preferably further contains a cationic curing agent.

[Solid epoxy resin]
The solid epoxy resin is an epoxy resin that is solid at room temperature (room temperature). For example, (a) a solid bisphenol type epoxy resin, (a) a solid hydrogenated bisphenol type epoxy resin, (c) a phenoxy resin. (D) 1,2-epoxy-4- (2-oxiranyl) cyclohexane adduct of 2,2-bis (hydroxymethyl) -1-butanol (this compound may be referred to as “solid epoxy adduct” for convenience) Can be preferably used.

  The content of the solid epoxy resin in the total amount of the epoxy resin including the solid epoxy resin and the liquid epoxy resin is, for example, 0 to 90% by mass, and preferably 75 to 85% by mass. In the case of 90 mass% or less, the toughness and transparency of the resin composition film and the cured product of the resin composition (that is, the resin layer) can be further improved in a balanced manner. Moreover, it becomes easier to adjust the tackiness of the resin composition film. Moreover, the possibility that the film or cured product of the resin composition (which may be referred to as “cured product etc.” together) becomes brittle and powders are further reduced.

(A: Solid bisphenol type epoxy resin)
By containing a solid bisphenol type epoxy resin, the brittleness of the cured product or the like can be suppressed, and the toughness of the cured product or the like can be increased. Moreover, transparency of hardened | cured material etc. can be improved. Moreover, it can adjust so that the tackiness of the film of a resin composition may become low.

  The solid bisphenol type epoxy resin that can be used in the present embodiment is not particularly limited. For example, solid bisphenol A type epoxy resin, solid bisphenol F type epoxy resin, solid bisphenol E type epoxy resin, solid bisphenol S type epoxy resin and the like can be mentioned. These can be used individually by 1 type or in combination of 2 or more types.

  The content of the solid bisphenol type epoxy resin in the solid epoxy resin is, for example, 0 to 85% by mass. In the case of 85 mass% or less, the toughness and transparency of the cured product can be further improved in a balanced manner. Moreover, the possibility of powder falling from the cured product or the like is further reduced.

  Examples of the solid bisphenol type epoxy resin include “Epicoat 1006FS” (solid bisphenol A type epoxy resin) manufactured by Japan Epoxy Resin Co., Ltd. and “Epicoat 4007” (solid bisphenol F type manufactured by Japan Epoxy Resin Co., Ltd.). Epoxy resin).

(I: Solid hydrogenated bisphenol type epoxy resin)
By containing a solid hydrogenated bisphenol type epoxy resin, the transparency of the cured product of the resin composition can be enhanced. Moreover, it can adjust so that the tackiness of the film of a resin composition may become low.

  The solid hydrogenated bisphenol type epoxy resin that can be used in the present embodiment is not particularly limited. For example, solid hydrogenated bisphenol A type epoxy resin, solid hydrogenated bisphenol F type epoxy resin, solid hydrogenated bisphenol E type epoxy resin, solid hydrogenated bisphenol S type epoxy resin, and the like can be mentioned. These can be used individually by 1 type or in combination of 2 or more types.

  The content of the solid hydrogenated bisphenol type epoxy resin in the solid epoxy resin is, for example, 0 to 85% by mass. In the case of 85 mass% or less, the toughness and transparency of the cured product can be further improved in a balanced manner.

  Examples of the solid hydrogenated bisphenol type epoxy resin include “YL7170” (solid hydrogenated bisphenol A type epoxy resin) manufactured by Japan Epoxy Resin Co., Ltd.

(U: Phenoxy resin)
The phenoxy resin is, for example, a polyhydroxy polyether synthesized from an epoxy compound and epichlorohydrin. By containing this, the brittleness of the cured product of the resin composition is suppressed, and the toughness of the cured product is increased. Can be increased. Moreover, transparency of hardened | cured material etc. can be improved. Moreover, it can adjust so that the tackiness of the film of a resin composition may become low. Moreover, it can adjust so that the viscosity of the varnish (solvent solution) prepared when producing the film of a resin composition may become high. Therefore, it becomes easy to produce a film of the resin composition.

  The content of this phenoxy resin in the solid epoxy resin is, for example, 0 to 30% by mass. In the case of 30% by mass or less, the viscosity of the varnish becomes more appropriate, and the varnish becomes easier to handle.

  Examples of the phenoxy resin include “YP50” manufactured by Toto Kasei Co., Ltd. A phenoxy resin can be used individually by 1 type or in combination of 2 or more types.

(E: Solid epoxy adduct)
The solid epoxy adduct is a transparent alicyclic epoxy resin that is solid at normal temperature (room temperature), and by containing this, the transparency of the cured product of the resin composition can be enhanced. Moreover, it can adjust so that the glass transition temperature (Tg) of hardened | cured material may become high.

  The content of the solid epoxy adduct in the solid epoxy resin is, for example, 0 to 85% by mass. In the case of 85 mass% or less, the toughness and transparency of the cured product can be further improved in a balanced manner.

  Examples of the solid epoxy adduct include “EHPE3150” manufactured by Daicel Chemical Industries, Ltd. The solid epoxy adduct can be used alone or in combination of two or more.

[Liquid epoxy resin]
The liquid epoxy resin is an epoxy resin that is liquid at room temperature (room temperature). For example, (f) liquid bisphenol type epoxy resin, (g) liquid hydrogenated bisphenol type epoxy resin, (g) liquid 3,4- Epoxy resins having an epoxycyclohexenyl skeleton, (K) liquid aliphatic epoxy resins, and the like can be preferably used.

  Content of the liquid epoxy resin in the epoxy resin whole quantity which match | combined the solid epoxy resin and liquid epoxy resin is 10-100 mass%, for example, Preferably, it is 15-25 mass%. In the case of 10% by mass or more, the toughness and transparency of the cured product can be further improved in a balanced manner. Moreover, it becomes easier to adjust the tackiness of the resin composition film. Moreover, the possibility of powder falling from the cured product or the like is further reduced.

(F: Liquid bisphenol type epoxy resin)
By containing a liquid bisphenol-type epoxy resin, the brittleness of the cured product of the resin composition can be suppressed, and the toughness of the cured product can be increased. Moreover, transparency of hardened | cured material etc. can be improved. Moreover, it can adjust so that the tackiness of the film of a resin composition may become high.

  The liquid bisphenol type epoxy resin that can be used in the present embodiment is not particularly limited. For example, a liquid bisphenol A type epoxy resin, a liquid bisphenol F type epoxy resin, a liquid bisphenol E type epoxy resin, a liquid bisphenol S type epoxy resin and the like can be mentioned. These can be used individually by 1 type or in combination of 2 or more types.

  The content of the liquid bisphenol type epoxy resin in the liquid epoxy resin is, for example, 0 to 25% by mass. When the amount is 25% by mass or less, the tackiness of the resin composition film is further easily adjusted.

  Examples of the liquid bisphenol type epoxy resin include “Epiclon 850S” (liquid bisphenol A type epoxy resin) manufactured by DIC, “Epicron 830S” (liquid bisphenol F type epoxy resin) manufactured by DIC, and the like.

(G: Liquid hydrogenated bisphenol type epoxy resin)
By containing a liquid hydrogenated bisphenol type epoxy resin, the transparency of the cured product of the resin composition can be enhanced. Moreover, it can adjust so that the tackiness of the film of a resin composition may become high.

  The liquid hydrogenated bisphenol type epoxy resin that can be used in the present embodiment is not particularly limited. Examples thereof include liquid hydrogenated bisphenol A type epoxy resin, liquid hydrogenated bisphenol F type epoxy resin, liquid hydrogenated bisphenol E type epoxy resin, liquid hydrogenated bisphenol S type epoxy resin, and the like. These can be used individually by 1 type or in combination of 2 or more types.

  The content of the liquid hydrogenated bisphenol type epoxy resin in the liquid epoxy resin is, for example, 0 to 25% by mass. When the amount is 25% by mass or less, the tackiness of the resin composition film is further easily adjusted.

  Examples of the liquid hydrogenated bisphenol type epoxy resin include “YX8000” (liquid hydrogenated bisphenol A type epoxy resin) manufactured by Japan Epoxy Resin Co., Ltd.

(K: Epoxy resin having a liquid 3,4-epoxycyclohexenyl skeleton)
By containing an epoxy resin having a liquid 3,4-epoxycyclohexenyl skeleton, the transparency of the cured product of the resin composition can be enhanced. Moreover, it can adjust so that the tackiness of the film of a resin composition may become high. Moreover, the photocuring speed of the film of a resin composition can be raised. Further, the glass transition temperature (Tg) of the cured product of the resin composition can be increased or decreased depending on the molecular structure.

  The epoxy resin having a liquid 3,4-epoxycyclohexenyl skeleton that can be used in the present embodiment is not particularly limited. For example, liquid 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexene carboxylate, liquid ε-caprolactone modified 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, etc. Is mentioned. These can be used individually by 1 type or in combination of 2 or more types.

  The content of the epoxy resin having a liquid 3,4-epoxycyclohexenyl skeleton in the liquid epoxy resin is, for example, 0 to 20% by mass. In the case of 20% by mass or less, the tackiness of the resin composition film is further easily adjusted.

  As an epoxy resin having a liquid 3,4-epoxycyclohexenyl skeleton, for example, “Celoxide 2021P” (liquid 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexene carboxy manufactured by Daicel Chemical Industries, Ltd.) Rate), “Celoxide 2081” (liquid ε-caprolactone-modified 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate) manufactured by Daicel Chemical Industries, Ltd.

(K: Liquid aliphatic epoxy resin)
By containing a liquid aliphatic epoxy resin, the transparency of the cured product of the resin composition can be enhanced. Moreover, it can adjust so that the tackiness of the film of a resin composition may become high.

  The liquid aliphatic epoxy resin that can be used in the present embodiment is not particularly limited. For example, a trimethylolpropane type epoxy resin, a polyethylene glycol type epoxy resin, a polypropylene glycol type epoxy resin, etc. are mentioned. These can be used individually by 1 type or in combination of 2 or more types.

  The content of the liquid aliphatic epoxy resin in the liquid epoxy resin is, for example, 0 to 20% by mass. In the case of 20% by mass or less, the tackiness of the resin composition film is further easily adjusted.

  Examples of liquid aliphatic epoxy resins include “Epototo YH300” (trimethylolpropane type epoxy resin) manufactured by Toto Kasei Co., Ltd. and “Epiol E-1000” (polyethylene glycol type epoxy resin) manufactured by Nippon Oil & Fats. .

[Cationic curing agent]
The cationic curing agent is a polymerization initiator for ring-opening self-polymerization of the epoxy group of the epoxy resin, and is a photocationic curing agent that can be cured only by light, a thermal cationic curing agent that can be cured only by heat, and by light. There are light and heat cationic curing agents that can be cured by heat and heat. The cationic curing agent that can be used in the present embodiment is not particularly limited, and any cationic curing agent can be used, and one kind can be used alone, or two or more kinds can be used in combination. By containing a cationic curing agent, the transparency of the cured product of the resin composition can be enhanced.

  Content of the cationic hardening | curing agent in a resin composition is 0.5-2 mass parts with respect to 100 mass parts of epoxy resins, for example. In the case of 0.5 parts by mass or more, the effect of the cationic curing agent is more certain. In the case of 2 parts by mass or less, the curing reaction proceeds at a more preferable rate.

  Examples of the photocationic curing agent include “SL-170” (SbF6-based sulfonium salt) manufactured by Adeka Corporation. Examples of the thermal cationic curing agent include “SI-150L” (SbF6-based sulfonium salt) manufactured by Sanshin Chemical Industry Co., Ltd.

[Rubber particles]
The rubber particles are made of a different kind of transparent resin from the epoxy resin. By containing such rubber particles, the structure of the resin layer becomes uneven, and by etching the resin layer, irregularities are formed on the outer surface of the resin layer, an anchor effect is obtained, and the resin layer Metal plating can be formed on the top with good adhesion. As a result, the adhesion of the electric circuit is improved. Moreover, since the rubber particles are made of a transparent resin, the transparency of the resin layer does not deteriorate even if the structure of the resin layer becomes uneven. As a result, light coupling between the light emitting / receiving element on the electric circuit and the optical waveguide is ensured. In addition, since the peeling area is increased by the extension of the rubber particles remaining in the resin layer after the etching treatment, the adhesion of the metal plating to the resin layer is also improved from this point.

  The rubber particles that can be used in the present embodiment are not particularly limited. For example, transparent particles composed of a polymer such as an acrylic (acrylate, methacrylate) monomer, a styrene monomer, a vinyl monomer, a diene monomer or the like, or at least one of these copolymers. These are resins having etching rates different from those of epoxy resins and relatively high transparency. In addition, any rubber particles composed of a transparent resin having an etching rate different from that of the epoxy resin can be used. These can be used individually by 1 type or in combination of 2 or more types.

  When the etching rate of the rubber particles is larger than the etching rate of the epoxy resin, the outer surface of the resin layer becomes a rough surface on which the convex portions of the epoxy resin are formed by the etching process. On the other hand, when the etching rate of the epoxy resin is higher than the etching rate of the rubber particles, the outer surface of the resin layer becomes a rough surface on which convex portions of the rubber particles are formed by the etching process. When rubber particles having an etching rate larger than that of the epoxy resin and rubber particles having a small etching rate are used in combination, the surface becomes a rough surface in which convex portions made of epoxy resin and convex portions made of rubber particles are mixed.

  Content of the rubber particle in a resin composition is 3-30 mass parts with respect to 100 mass parts of epoxy resins, for example, Preferably, it is 5-10 mass parts. If the rubber particle content is excessively small, the effect of improving the adhesion of the electric circuit tends to be insufficient. When the content of rubber particles is excessively large, the transparency of the resin layer tends to decrease. Further, the entire resin layer has a rubbery property and tends to be easily deformed.

  The particle size of the rubber particles in the resin composition is, for example, 30 to 3000 nm, preferably 50 to 500 nm. When the particle size of the rubber particles is excessively small, the unevenness formed on the outer surface of the resin layer becomes excessively fine, the anchor effect is lowered, and the adhesion improving effect of the electric circuit tends to be insufficient. In addition, the rubber particles tend to agglomerate, and the transparency of the resin layer tends to decrease. When the particle size of the rubber particles is excessively large, it tends to be difficult to reduce the thickness of the resin layer. In addition, it tends to be difficult to reduce the thickness of the resin composition film. Further, the transparency of the resin layer tends to decrease.

  In this embodiment, rubber particles are dispersed in advance in a solvent such as liquid epoxy resin or methyl ethyl ketone (MEK), for example, and the dispersion is mixed with the epoxy resin, thereby improving the dispersibility of the rubber particles. The resin composition is preferable because it is easy to prepare.

  Specific examples of rubber particles that can be used in the present embodiment include “XSK-500” (styrene butadiene rubber) manufactured by JSR. This is a dispersion in which nano-sized styrene butadiene rubber is dispersed in methyl ethyl ketone. These rubber particles have a primary particle diameter of about 70 nm and have a hydroxyl group or a carboxyl group on the particle surface, so that they are excellent in compatibility with an epoxy resin.

  Other specific examples of rubber particles that can be used in the present embodiment include, for example, “EA-1135” (acrylic-styrene copolymer rubber particles) manufactured by Ganz Kasei Co., Ltd., “MS-” manufactured by Soken Chemical Co., Ltd. 300K "(acrylic rubber particles)," XX-1873-Z "(micron-sized crosslinked styrene-acrylic copolymer rubber particles) manufactured by Sekisui Chemical Co., Ltd., and the like.

  By making the refractive index of the rubber particles and the refractive index of the cured epoxy resin substantially the same, the difference in the refractive index in the resin layer is eliminated, and the transparency of the resin layer is further improved. For example, since the refractive index of rubber particles of “EA-1135” manufactured by Gantz Chemical Co., Ltd. is 1.53, the composition of the epoxy resin (solid state) is set so that the refractive index of the cured epoxy resin is 1.53 What is necessary is just to determine the kind of epoxy resin and a liquid epoxy resin, content). Thereby, the transparency of the resin layer is further improved, and the high transparency of the resin layer and the good adhesion of the metal plating to the resin layer are more compatible.

[Other additives]
In the present embodiment, the resin composition may include other additives such as a surface conditioner, a coupling agent, a flow modifier, a lubricant, and a colorant as necessary, as long as the object of the present invention is not impaired. And can be further contained.

[Method of forming resin layer]
In the present embodiment, the resin layer is formed by laminating the resin composition on the optical waveguide and curing in the resin layer forming step. As a method of laminating the resin composition in this case, a method of preparing a varnish (solvent solution) of the resin composition, applying the varnish on the optical waveguide, and then removing the solvent and drying (direct coating method) There is.

  The solvent that can be used for preparing the varnish is not particularly limited as long as it can dissolve the above-described epoxy resin, cationic curing agent, and other additives. Examples thereof include methyl ethyl ketone (MEK), toluene, cyclohexanone, propylene glycol monomethyl ether acetate (PGMEA) and the like. These can be used individually by 1 type or in combination of 2 or more types.

  The mixing ratio of the epoxy resin, rubber particles and the like in the varnish and the solvent is not particularly limited. For example, what is necessary is just to adjust suitably so that the viscosity of a varnish may become a viscosity preferable for apply | coating a varnish on an optical waveguide.

[Resin composition film]
In this embodiment, as a method of laminating the resin composition in the resin layer forming step, instead of the direct coating method, a resin composition film in which the resin composition is formed in advance is prepared, and this film is used as an optical waveguide. A method of laminating the film (film method) can also be employed. In this film method, it is not necessary to perform a varnish application operation and a drying operation in the resin layer forming step, so that the productivity of the photoelectric composite wiring board is improved. In addition, the thickness of the film and thus the thickness of the resin layer can be easily and accurately made uniform. The thickness of the film is not particularly limited. For example, it is about 10 to 100 μm.

  The film of the resin composition is produced, for example, by applying a varnish of the resin composition on a PET film or the like using a multi coater of a comma coater head or the like, and then removing the solvent and drying. A protective film is usually heat laminated on the produced film. Then, after the protective film is peeled off, the resin composition film is laminated on the optical waveguide using, for example, a vacuum laminator or the like. In addition, in the manufacturing method and Example of the photoelectric composite wiring board mentioned later, the film of this resin composition may be described as "the curable film for resin layers".

  As the varnish used in this film method, the same varnish used in the direct coating method can be used.

<Method for manufacturing photoelectric composite wiring board>
Next, a method for producing a metal-clad laminate and a photoelectric composite wiring board using the resin composition will be described in detail with reference to FIG.

  FIG. 1 is a schematic cross-sectional view for explaining a method for producing a metal-clad laminate and a photoelectric composite wiring board in the present embodiment. In FIG. 1, reference numeral 3 is a core, reference numeral 4 is a mirror surface, reference numeral 6 is an optical waveguide, reference numeral 8 is a resin composition, reference numeral 8a is an epoxy resin, reference numeral 8b is rubber particles, reference numeral 8c is unevenness (rough surface), reference numeral 8d is a resin layer, 9 is a metal plating, 9d is a metal layer, 10 is an electric circuit, 20 is a photoelectric composite wiring board, and 25 is a clad.

[Optical waveguide]
First, as shown in FIG. 1A, an optical waveguide 6 is prepared. As indicated by the arrow line, the optical waveguide 6 propagates by totally reflecting the guided light input to the mirror surface 4 at one end at the interface between the core 3 and the clad 25 having different refractive indexes, and the mirror surface at the other end. 4, and an optical circuit is provided by the optical waveguide 6.

  The manufacturing method of the optical waveguide 6 is not particularly limited. Various methods for manufacturing the optical waveguide 6 are known. An example will be described (for details, refer to the examples described later). For example, a clad curable film prepared in advance is laminated on a temporary substrate made of polycarbonate resin, and the film is cured with light and / or heat to form a first clad. A core curable film prepared in advance is laminated on the first clad. Here, the refractive index of the core curable film is adjusted to be higher than the refractive index of the clad curable film. A negative mask having a core pattern slit formed thereon is placed on the core curable film, and exposed to ultraviolet rays or the like. As an exposure method, in addition to a method using a negative mask, a direct drawing method in which laser light is irradiated along the core pattern may be used. After the exposure, an unexposed / uncured portion of the core curable film is removed by developing with a developer such as a water-based flux cleaning agent. Thereby, the core 3 is formed on the first cladding. Next, mirror surfaces 4 and 4 for deflecting the guided light by 90 ° are formed at both ends of the core 3. A clad curable film is laminated so as to cover the first clad and the core 3, and this film is cured with light and / or heat to form a second clad. In this way, the optical waveguide 6 having the core 3 and the clad 25 surrounding the core 3 is obtained.

[Resin layer forming step]
In the resin layer forming step, as shown in FIG. 1B, on the optical waveguide 6, an epoxy resin 8a and a resin containing rubber particles 8b made of a transparent resin of a different type from the epoxy resin 8a. In this step, the resin layer 8d is formed by laminating and curing the composition 8. Here, the resin composition according to this embodiment described above is used as the resin composition 8. As described above, the method of laminating the resin composition 8 may be a direct coating method or a film method using a curable film for a resin layer. In the case of the film method, for example, a curable film for a resin layer is laminated on the optical waveguide 6 using a vacuum laminator or the like. The resin composition 8 is cured by light and / or heat. The thickness of the resin layer 8d is not particularly limited. For example, it is about 10 to 100 μm.

[Etching process]
The etching process is a process of etching the formed resin layer 8d as shown in FIG. By this etching process, unevenness (rough surface) 8c is formed on the outer surface of the resin layer 8d. In addition, since the etching rate of the rubber particle 8b is larger than the etching rate of the epoxy resin 8a, the illustrated example shows a case where a concave portion is formed at the rubber particle 8b portion and a convex portion is formed by the epoxy resin 8a. However, the present invention is not limited to this, and since the etching rate of the epoxy resin 8a is larger than the etching rate of the rubber particles 8b, the concave portions are formed in the epoxy resin 8a, and the convex portions by the rubber particles 8b may be formed. . In the former case, the fineness of the concave portion is determined depending on the particle diameter of the rubber particle 8b, and in the latter case, the fineness of the concave portion is determined depending on the content of the rubber particle 8b. Also, the rubber particles 8b having an etching rate larger than the etching rate of the epoxy resin 8a and the rubber particles 8b having a small etching rate may be used in combination so that the convex portions by the epoxy resin 8a and the convex portions by the rubber particles 8b are mixed. Good. The etching process is performed by a permanganate process (desmear process) using a permanganate solution, which is a pretreatment for metal plating.

[Metal layer forming process]
As shown in FIG. 1D, the metal layer forming step is a step of forming a metal layer 9d by applying metal plating 9 on the etched resin layer 8d. Here, the boundary surface between the resin layer 8d and the metal layer 9d is a rough surface, and the anchor effect is obtained by the unevenness (rough surface) 8c formed on the outer surface of the resin layer 8d. It is formed on the top with good adhesion. The metal plating 9 is formed by, for example, an electroless plating process of a metal such as copper or an electroless plating process of a metal such as copper and a subsequent electrolytic plating process. The thickness of the metal plating 9 is not particularly limited. For example, it is about 10-50 micrometers. By this metal layer forming step, a metal-clad laminate is obtained.

[Electric circuit formation process]
The electric circuit forming step is a step of forming the formed metal layer 9d on the electric circuit 10 as shown in FIG. The electric circuit 10 can be formed by, for example, a well-known etching technique for forming a circuit. Here, since the boundary surface between the resin layer 8d and the electric circuit 10 is a rough surface, and the anchor effect is obtained by the unevenness (rough surface) 8c formed on the outer surface of the resin layer 8d, the electric circuit 10 has the resin layer 8d. It is formed on the top with good adhesion. As described above, the photoelectric composite wiring board 20 including the optical circuit (optical waveguide 6) and the electric circuit 10 is obtained by this electric circuit forming step.

  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.

<Production of resin composition film>
[Film 1]
As shown in Table 1 (numerical values for blending are parts by mass), 62 parts by mass of (A) solid epoxy adduct (“EHPE3150” manufactured by Daicel Chemical Industries, Ltd.) and (B) phenoxy resin (Tokyo) 18 parts by mass of “YP50” manufactured by Kasei Co., Ltd. 8 parts by mass of (C) trimethylolpropane type epoxy resin (“Epototo YH300” manufactured by Tohto Kasei Co., Ltd.) as liquid epoxy resin and (D) liquid bisphenol A type epoxy resin ("Epiclon 850S" manufactured by DIC) 12 parts by mass, (J) Nano-sized styrene butadiene rubber dispersed in methyl ethyl ketone as rubber particles ("XSK-500" manufactured by JSR) 5 parts by mass (rubber particles (E) 0.5 parts by mass of “SP-170” manufactured by Adeka as photocationic curing agent, (F) Sanshin as thermal cationic curing agent "SI-150L" 0.5 parts by mass from Gaku Kogyo Co., Ltd. and (G) 0.1 parts by mass of "F470" made by DIC as a surface conditioner, A varnish of the resin composition was prepared by dissolving in a mixed solvent with 70 parts by mass of methyl ethyl ketone (MEK) at 60 ° C. under reflux. 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 50 μm. A film (resin layer curable film) 1 was prepared. “OPP-MA420” manufactured by Oji Specialty Paper Co., Ltd. was thermally laminated as a protective film on the produced film.

[Film 2]
As shown in Table 1, a film 2 was produced in the same manner as the film 1 except that the blending amount of the rubber particles (J) was 10 parts by mass.

[Film 3]
As shown in Table 1, except that (K) micron-sized crosslinked styrene-acrylic copolymer rubber particles (“XX-1873-Z” manufactured by Sekisui Chemical Co., Ltd.) were used as rubber particles, A film 3 was produced in the same manner.

[Film 4]
As shown in Table 1, a film 4 was produced in the same manner as the film 3 except that the blending amount of the rubber particles (K) was 10 parts by mass.

[Film 5]
As shown in Table 1, a film 5 was produced in the same manner as the films 1 to 4 except that the rubber particles (J) and (K) were not blended.

Table 1 summarizes the raw materials used.
(A) Solid epoxy adduct (“EHPE3150” manufactured by Daicel Chemical Industries, Ltd.)
(B) Phenoxy resin (“YP50” manufactured by Toto Kasei Co., Ltd.)
(C) Trimethylolpropane type epoxy resin (“Epototo YH300” manufactured by Tohto Kasei Co., Ltd.)
(D) Liquid bisphenol A type epoxy resin (“Epiclon 850S” manufactured by DIC)
(E) Photocationic curing agent (“SP-170” manufactured by Adeka)
(F) Thermal cationic curing agent (“SI-150L” manufactured by Sanshin Chemical Industry Co., Ltd.)
(G) Surface conditioner (“F470” manufactured by DIC)
(H) Toluene (I) Methyl ethyl ketone (MEK)
(J) Dispersion in which nano-sized styrene-butadiene rubber is dispersed in methyl ethyl ketone (“XSK-500” manufactured by JSR)
(K) Micron-sized crosslinked styrene-acrylic copolymer rubber particles ("XX-1873-Z" manufactured by Sekisui Chemical Co., Ltd.)

<Evaluation of physical properties of cured product of resin composition>
[transparency]
The protective film is peeled off from the produced resin composition film, and this is exposed by irradiating with ultraviolet light under the condition of 4 J / cm ² using an ultrahigh pressure mercury lamp, and further subjected to heat treatment at 150 ° C. for 1 hour. A cured product of the resin composition was obtained. The obtained cured product was visually observed to evaluate the transparency of the cured product. As the evaluation criteria, “◯” indicates transparent, slightly cloudy, but “Δ” indicates practical level, and “×” indicates cloudy. The results are shown in Table 1.

[Peel strength of metal plating]
In order to evaluate the adhesion of the metal plating to the cured product of the resin composition, the peel strength of the metal plating was measured. That is, the protective film was peeled off from the produced resin composition film, and this was printed under the conditions of 60 ° C. and 0.2 MPa using a pressure-type vacuum laminator (“V-130” manufactured by Nichigo Morton). Laminated on the wiring board. Using an ultra-high pressure mercury lamp, the resin composition was exposed by irradiating with ultraviolet light under conditions of 4 J / cm ² , and after further removing the PET film from the resin composition film, heat treatment was performed at 150 ° C. for 1 hour. A cured product of the product was formed. The formed cured product was subjected to an etching treatment through a swelling step, a permanganic acid treatment step, and a reduction treatment step. The cured product subjected to the etching treatment was subjected to a cleaner conditioning process, a soft etching process, a pre-dip process, a catalyst process, an accelerator process, and an electroless copper plating process, whereby electroless copper plating was performed on the cured product. Subsequently, a copper plating with a thickness of 30 μm was applied on the cured product through a degreasing step, an acid activation step, an electrolytic copper plating step, and a rust prevention step. This was cut into a strip having a width of 10 mm to obtain a test piece, and the peel strength of copper plating on the test piece was measured using a peel tester “EZ-Test” (50N load cell) manufactured by Shimadzu Corporation. The results are shown in Table 1.

[Consideration of results]
The film 5 of the resin composition containing no rubber particles was excellent in transparency of the cured product, but the peel strength of the copper plating for the cured product was extremely small as less than 0.01 N / mm. On the other hand, as for the films 1-4 of the resin composition containing a rubber particle, the peel strength of the copper plating with respect to hardened | cured material is improved, and the adhesiveness of the electric circuit formed from copper plating improves. Recognize. In particular, the films 1 and 2 in which the primary particle diameter of the rubber particles is about 70 nm and nano-size were excellent in transparency of the cured product as compared with the films 3 and 4 in which the particle diameter of the rubber particles was micron-size. . As described above, the cured product of the resin composition containing the epoxy resin and the rubber particles composed of a transparent resin different from the epoxy resin has a level of practically no problem in transparency, and an electric circuit. Therefore, in a photoelectric composite wiring board having an optical circuit and an electric circuit, it can be suitably used as a resin layer for compounding the optical waveguide and the electric circuit.

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

[Curable curable film]
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 Tohto Kasei 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.

[Curable film for resin layer]
62 parts by mass of (A) solid epoxy adduct (“EHPE3150” manufactured by Daicel Chemical Industries, Ltd.) and 18 parts by mass of phenoxy resin (“YP50” manufactured by Tohto Kasei Co., Ltd.) as a solid epoxy resin, liquid epoxy resin (C) 8 parts by mass of trimethylolpropane type epoxy resin (“Epototo YH300” manufactured by Toto Kasei Co., Ltd.) and (D) 12 parts by mass of liquid bisphenol A type epoxy resin (“Epiclon 850S” manufactured by DIC) 5 parts by mass (as rubber particles) of (J) nano-sized styrene butadiene rubber dispersed in methyl ethyl ketone as particles ("XSK-500" manufactured by JSR), (E) manufactured by Adeka as photocationic curing agent "SP-170" 0.5 parts by mass, (F) "SI-150L" 0.5 quality manufactured by Sanshin Chemical Industry Co., Ltd. as a thermal cation curing agent And (G) 0.1 part by mass of “F470” manufactured by DIC as a surface conditioner was refluxed in a mixed solvent of 30 parts by mass of (H) toluene and 70 parts by mass of methyl ethyl ketone (MEK). The varnish of the epoxy resin composition for resin layers was prepared by making it melt | dissolve under 60 degreeC below. 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. “OPP-MA420” manufactured by Oji Specialty Paper Co., Ltd. was thermally laminated as a protective film on the produced film.

[Fabrication of optical waveguide]
FIG. 2 is a schematic cross-sectional view for explaining a method for producing a metal-clad laminate and a photoelectric composite wiring board in the examples. In FIG. 2, reference numeral 1 is a temporary substrate, reference numeral 2 is a first cladding, reference numeral 3 is a core, reference numeral 4 is a mirror surface (gold thin film), reference numeral 5 is a second cladding, reference numeral 6 is an optical waveguide, and reference numeral 7 is Substrate, 8 is a resin composition, 8a is an epoxy resin, 8b is rubber particles, 8c is uneven (rough surface), 8d is a resin layer, 8f is a curable film for a resin layer, and 9 is a metal. Reference numeral 9d denotes a metal (copper) layer, reference numeral 10 denotes an electric circuit, and reference numeral 20 denotes a photoelectric composite wiring board.

The protective film is peeled off from the curable film for clad having a thickness of 10 μm, and this is subjected to ultraviolet rays using a pressure type vacuum laminator (“V-130” manufactured by Nichigo Morton) under the conditions of 60 ° C. and 0.2 MPa. The substrate was laminated on a 140 mm × 120 mm temporary substrate 1 made of a permeable polycarbonate resin. Using an ultra-high pressure mercury lamp, it is exposed to ultraviolet light under the condition of ² J / cm ² , and after peeling the PET film from the curable film for cladding, heat treatment is performed at 150 ° C. for 30 minutes, and oxygen plasma treatment Was applied to form a first clad 2 in which the clad curable film was cured.

Next, the protective film is peeled off from the curable film for core having a thickness of 40 μm, and this is subjected to conditions of 60 ° C. and 0.2 MPa using a pressure type vacuum laminator (“V-130” manufactured by Nichigo Morton). Then, it was laminated on the first clad 2. A negative mask on which core pattern slits (slit widths of 40 μm and slit lengths of 120 mm) are formed is placed on a core curable film, and an ultra-high pressure mercury lamp is used for ultraviolet irradiation under conditions of 4 J / cm ^2. After exposure to light, the negative mask is removed, the PET film is peeled off from the curable film for the core, heat treatment is performed at 140 ° C. for 2 minutes, and a water-based flux cleaning agent adjusted to 55 ° C. as a developer (Arakawa) By developing using “Pine Alpha ST-100SX” manufactured by Chemical Industry Co., Ltd., the unexposed / uncured portion of the curable film for the core is dissolved and removed, and after finishing washing with water and air blowing, A core in which the exposed portion of the curable film for core is cured according to the core pattern by drying at 100 ° C. for 10 minutes. It was formed on the first cladding 2 (see FIG. 2 (a)).

  Here, when the surface state of the first cladding 2 was visually observed, no roughness was observed on the surface of the first cladding 2. Further, when the appearance of the core 3 was observed with a stereomicroscope, no roughness was observed on the side wall of the core 3.

Next, a micromirror for deflecting the guided light by 90 ° was formed at a position 10 mm from both ends of the core 3. That is, first, a rotating blade (“# 5000” blade manufactured by Disco Corporation) with a cutting blade having an apex angle of 90 ° is applied from both ends of the core 3 at a rotational speed of 10,000 rpm and a moving speed of 0.1 mm / s. Each V-groove having a depth of 50 μm was formed by moving across a position of 10 mm. Next, a diluted solution obtained by diluting a varnish of an epoxy resin composition for a clad prepared for producing a curable film for a clad 50 times with a mixed solvent of 30 parts by mass of toluene and 70 parts by mass of methyl ethyl ketone is added to the V groove. After thinly applying with a brush and drying at 100 ° C. for 30 minutes, using an ultra-high pressure mercury lamp, exposure is performed by irradiating with ultraviolet light under the condition of 1 J / cm ² , and further heat treatment is performed at 120 ° C. for 10 minutes. The V groove was smoothed. Next, a gold thin film having a thickness of 1000 mm was formed on the surface of the V-groove by covering the metal mask with only the V-groove portion opened and vacuum-depositing the gold, thereby forming the mirror surface 4 of the micromirror. (See FIG. 2 (b)).

Next, the protective film is peeled off from the curable film for cladding having a thickness of 50 μm, and this is subjected to conditions of 80 ° C. and 0.3 MPa using a pressure type vacuum laminator (“V-130” manufactured by Nichigo Morton). Thus, the first clad 2 and the core 3 were laminated so as to cover the first clad 2 and the core 3 (see FIG. 2C). The PET film is peeled off from the curable film for clad, and a pressure type vacuum laminator (“V-130” manufactured by Nichigo Morton) is used on the peeled surface under the conditions of 80 ° C. and 0.2 MPa, A substrate 7 (“FR4” manufactured by Panasonic Electric Works Co., Ltd.) was laminated (see FIG. 2D). From the temporary substrate 1 side, exposure was performed by irradiating with ultraviolet light under the condition of ² J / cm ² using an ultrahigh pressure mercury lamp, and further heat treatment was performed at 140 ° C. for 1 hour, whereby the curable film for cladding was cured. A second cladding 5 was formed. By removing the temporary substrate 1, the optical waveguide 6 having the core 3 and the clads 2 and 5 enclosing the core 3 was obtained in a state of being bonded to the substrate 7 (see FIG. 2 (e)).

[Resin layer forming step]
Next, the protective film is peeled off from the curable film 8f for resin layer having a thickness of 20 μm, and this is applied at 60 ° C. and 0.2 MPa using a pressure type vacuum laminator (“V-130” manufactured by Nichigo Morton). The optical waveguide 6 was laminated under the conditions described above. By using an ultra-high pressure mercury lamp to irradiate with ultraviolet light under conditions of 4 J / cm ² , and after removing the PET film from the resin layer curable film 8f, heat treatment is performed at 150 ° C. for 30 minutes, A resin layer 8d in which the resin layer curable film 8f was cured was formed (see FIG. 2F).

[Etching process]
The formed resin layer 8d was subjected to an etching treatment through a swelling step, a permanganic acid treatment step, and a reduction treatment step (see FIG. 2G).

[Metal layer forming process]
The etched resin layer 8d is subjected to an electroless copper plating on the resin layer 8d through a cleaner conditioning process, a soft etching process, a pre-dip process, a catalyst process, an accelerator process, and an electroless copper plating process. did. Subsequently, through a degreasing step, an acid activation step, an electrolytic copper plating step, and a rust prevention step, a metal (copper) plating 9 having a thickness of 30 μm was applied on the resin layer 8d to form a metal (copper) layer 9d. (See FIG. 2 (h)). Here, a metal-clad laminate was produced.

[Electric circuit formation process]
The formed metal layer 9d is formed on the electric circuit 10 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 the optical circuit (optical waveguide 6) and the electric circuit 10 The photoelectric composite wiring board 20 provided with (refer Fig.2 (i)) was obtained.

<Evaluation of loss of photoelectric composite wiring board>
Loss evaluation of the obtained photoelectric composite wiring board 20 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 the optical waveguides 6 (optical circuit) of the photoelectric composite wiring board 20. The power (P1) of the light (P1) that enters the mirror surface 4 through the matching oil (silicone oil) and exits from the other mirror surface 4 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. In addition, the end portions of the two optical fibers were directly brought into contact with each other, and the power (P0) of light emitted without inserting the resin layer 8d and the optical waveguide 6 of the photoelectric composite wiring board 20 was measured with a power meter. Then, when the insertion loss of the photoelectric composite wiring board 20 was obtained from the calculation formula of “(−10) log (P1 / P0)”, it was as small as 2.5 dB and was sufficiently practical.

  As described above in detail with reference to specific examples, in the method of manufacturing the photoelectric composite wiring board 20 including the optical circuit 6 and the electric circuit 10, the optical waveguide 6 having the core 3 and the clad 25 that wraps the core 3 is used. A resin layer forming step for forming a resin layer 8d containing the epoxy resin 8a and rubber particles 8b made of a different kind of transparent resin from the epoxy resin 8a, and the formed resin layer 8d are etched. An etching treatment step, a metal layer formation step of forming a metal layer 9d by metal plating 9 on the etched resin layer 8d (so far, a metal-clad laminate is obtained), and the formed metal layer 9d. Are formed in the electric circuit 10 (so far, the photoelectric composite wiring board 20 is obtained), so that the outer surface of the resin layer 8d is formed in the etching process. Uneven (rough surface) 8c is formed, a metal plating 9, adhesion of the metal layer 9d and thus the electric circuit 10 is increased. Further, since the transparency of the resin layer 8d is at a level that does not cause a problem in practice, the coupling loss between the light receiving / emitting element such as a VCSEL on the electric circuit 10 and the optical waveguide 6 is suppressed.

  In addition, since the resin layer 8d and the metal layer 9d are built up on the optical waveguide 6 that has already been completed, the side wall of the core 3 is not roughened, and the waveguide loss of the optical waveguide 6 is suppressed. Also, the optical waveguide 6 and the electric circuit 10 are manufactured separately, and the optical waveguide 6 is manufactured by build-up with respect to the temporary substrate 1 instead of a manufacturing method in which these are bonded together. In contrast, since the optical circuit 6 and the electric circuit 10 are combined by build-up, the metal-clad laminate and the photoelectric composite wiring board 20 can be obtained with a high yield.

  The transparent resin constituting the rubber particle 8b is at least one of an acrylic monomer, a styrene monomer, a vinyl monomer, a diene monomer polymer, or a copolymer thereof. The etching rate is different from that of the epoxy resin 8a, and the transparency of the rubber particles 8b is relatively high.

  Further, in the resin layer forming step, when the film 8f (curable film for resin layer) of the resin composition 8 containing the epoxy resin 8a and the rubber particles 8b is laminated, conventionally, it is possible to manufacture a printed wiring board or light Since it can respond to facilities with a mass production record such as a vacuum laminator used for manufacturing the waveguide 6, the productivity of the metal-clad laminate and the photoelectric composite wiring board 20 is improved.

  In addition, when the content of the rubber particles 8b in the resin layer 8d is 3 to 30 parts by mass with respect to 100 parts by mass of the epoxy resin, the effect of improving the adhesion of the electric circuit 10 is ensured. Further, good transparency of the resin layer 8d is ensured. Further, the problem that the entire resin layer 8d is rubbery and easily deforms is suppressed.

  When the particle size of the rubber particles 8b in the resin layer 8d is 30 to 3000 nm, the unevenness 8c formed on the outer surface of the resin layer 8d becomes excessively fine, the anchor effect is lowered, and the electric circuit 10 Inadequate adhesion improving effect is suppressed. Further, the rubber particles 8b are likely to agglomerate, and the problem that the transparency of the resin layer 8d is reduced is suppressed. Further, the problem that it is difficult to reduce the thickness of the resin layer 8d due to the rubber particle 8b having a too large particle size is suppressed. Moreover, the malfunction that it becomes difficult to make thin the film 8f of the resin composition 8 is suppressed. Moreover, the malfunction that the transparency of the resin layer 8d falls is suppressed.

  Moreover, since the resin layer 8d contains a solid epoxy resin and a liquid epoxy resin as the epoxy resin 8a, the properties of the resin composition 8 are diversified, and desired properties (including the refractive index) by combining the epoxy resin components. ) Resin composition 8 can be obtained.

  Moreover, since the resin layer 8d further contains a cationic curing agent, the transparency of the resin layer 8d can be enhanced.

  The photoelectric composite wiring board 20 is formed on the optical waveguide 6 having the core 3 and the clad 25 enclosing the core 3, the resin layer 8d laminated on the optical waveguide 6, and the resin layer 8d. The resin layer 8d contains an epoxy resin 8a and rubber particles 8b made of a different type of transparent resin from the epoxy resin 8a. The resin layer 8d and the electric circuit 10 is a rough surface (concave / convex 8c) formed with a convex portion by the epoxy resin 8a and / or a convex portion by the rubber particles 8b, the adhesion of the electric circuit 10 is enhanced, and The coupling loss with the optical waveguide 6 is suppressed, and the waveguide loss of the optical waveguide 6 is suppressed.

  The metal-clad laminate is laminated on the optical waveguide 6 having the core 3 and the clad 25 enclosing the core 3, the resin layer 8d laminated on the optical waveguide 6, and the resin layer 8d. The resin layer 8d contains an epoxy resin 8a and rubber particles 8b made of a different type of transparent resin from the epoxy resin 8a. The resin layer 8d and the metal layer 9d Is a rough surface (concave / convex 8c) formed with a convex portion made of epoxy resin 8a and / or a convex portion made of rubber particles 8b, so that only by forming the metal layer 9d on the electric circuit 10, Adhesiveness of the circuit 10 is enhanced, coupling loss between the light emitting / receiving element and the optical waveguide 6 is suppressed, and the photoelectric composite wiring board 20 in which the waveguide loss of the optical waveguide 6 is suppressed can be obtained.

1 Temporary substrate 2 First clad 3 Core 4 Mirror surface (gold thin film)
5 Second clad 6 Optical waveguide (optical circuit)
7 Substrate 8 Resin composition 8a Epoxy resin 8b Rubber particle 8c Concavity and convexity (rough surface)
8d Resin layer 8f Resin layer curable film (resin composition film)
9 Metal plating 9d Metal layer 10 Electric circuit 20 Photoelectric composite wiring board 25 Clad

Claims (9)

An optical waveguide having a core and a cladding surrounding the core;
A resin layer laminated on the optical waveguide;
A metal layer laminated on the resin layer,
The resin layer contains an epoxy resin and rubber particles having a primary particle diameter of 50 to 500 nm, which is made of a transparent resin of a different type from the epoxy resin,
A metal-clad laminate in which a boundary surface between the resin layer and the metal layer is a rough surface on which convex portions made of epoxy resin and / or convex portions made of rubber particles are formed. An optical waveguide having a core and a cladding surrounding the core;
A resin layer laminated on the optical waveguide;
An electric circuit formed on the resin layer,
The resin layer contains an epoxy resin and rubber particles having a primary particle diameter of 50 to 500 nm, which is made of a transparent resin of a different type from the epoxy resin,
A photoelectric composite wiring board in which a boundary surface between the resin layer and the electric circuit is a rough surface on which a convex portion made of an epoxy resin and / or a convex portion made of rubber particles are formed.   The photoelectric composite wiring according to claim 2, wherein the transparent resin constituting the rubber particles is at least one of an acrylic monomer, a styrene monomer, a vinyl monomer, a diene monomer polymer, or a copolymer thereof. Board.   The photoelectric composite wiring board according to claim 2 or 3, wherein the content of the rubber particles in the resin layer is 3 to 30 parts by mass with respect to 100 parts by mass of the epoxy resin. The photoelectric composite wiring board according to any one of claims 2 to 4 , wherein the resin layer contains a solid epoxy resin and a liquid epoxy resin as an epoxy resin. Resin layer, a photoelectric composite wiring board according to any one of claims 2 to 5 which further contains a cationic curing agent. On an optical waveguide having a core and a clad surrounding the core, a resin layer containing an epoxy resin and rubber particles having a primary particle diameter of 50 to 500 nm and made of a transparent resin different from the epoxy resin is formed. A resin layer forming step,
An etching process for etching the formed resin layer;
On the etched resin layer, a metal layer forming step of forming a metal layer by metal plating,
A method for producing a metal-clad laminate comprising: On an optical waveguide having a core and a clad surrounding the core, a resin layer containing an epoxy resin and rubber particles having a primary particle diameter of 50 to 500 nm and made of a transparent resin different from the epoxy resin is formed. A resin layer forming step,
An etching process for etching the formed resin layer;
On the etched resin layer, a metal layer forming step of forming a metal layer by metal plating,
An electric circuit forming step of forming the formed metal layer in an electric circuit;
A method for manufacturing a photoelectric composite wiring board comprising: The method for producing a photoelectric composite wiring board according to claim 8 , wherein the resin layer is formed by laminating and curing a film of a resin composition containing an epoxy resin and rubber particles in the resin layer forming step.