JP2012098332A - Method of manufacturing photoelectric composite wiring board and photoelectric composite wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a photoelectric composite wiring board with high manufacturing efficiency.SOLUTION: A method of manufacturing an optical waveguide is employed. The method includes: a core portion forming step of forming a laminate by forming a core portion 13 on a surface of a first clad layer 12 formed on a substrate 11; a slope forming step of forming a slope 15a for reflecting light in the core portion 13; a metal layer forming step of forming a metal layer 16 at least on the slope 15a and at a position to form an electric circuit on a surface of the laminate at a side where the core portion 13 is formed; a metal layer removing step of removing the metal layer 16 so as to leave the metal layer 16 on the slope 15a and at the position to form the electric circuit, thereby forming a mirror portion 16a comprising the metal layer on the slope 15a simultaneously with forming an electric circuit 16b; and a clad layer forming step of forming a second clad layer 17 so as to bury the core portion 13 formed on the first clad layer 12.

Description

  The present invention relates to a method for manufacturing an opto-electric composite wiring board, and an opto-electric composite wiring board manufactured by the manufacturing method.

  Printed circuit boards and flexible wiring boards with built-in optical waveguides that guide light into the interior to solve the problems of high-frequency noise accompanying high-speed signals in various information processing devices and insufficient transmission bandwidth. Opto-electric composite wiring boards are attracting attention.

  In such an opto-electric composite wiring board, the light can be reflected at the core of the optical waveguide, etc., for the purpose of bending the light to a desired angle, for example, to input / output the light from the optical waveguide. A surface is formed. In addition, the opto-electric composite wiring board drives a light emitting element such as a vertical cavity surface emitting laser (VCSEL), a light receiving element such as a photodiode (PD), and a semiconductor element such as an integrated circuit (IC). An electric circuit needs to be provided.

  Examples of a method for producing such an optoelectric composite wiring board include the methods described in Patent Document 1 and Patent Document 2.

  In Patent Document 1, a press die is pressed on the substrate surface to form a groove in the substrate surface, an optical waveguide is formed in the groove, a metal layer is formed on the substrate surface after forming the groove, A method for manufacturing a circuit module is described in which electrical wiring is formed by patterning a metal layer.

  Further, in Patent Document 2, mirror members whose mirror surfaces are opposed to each other are arranged on a substrate, an optical waveguide is arranged between the mirror surfaces facing each other, and an optical surface including the upper surface on the mirror member is guided. A method of manufacturing an opto-electric wiring board by forming electric wiring on a waveguide is described.

JP 2006-208527 A JP 2006-292852 A

  In an opto-electric composite wiring board, a mirror part made of a metal layer is generally provided on an inclined surface formed in a core part of an optical waveguide in order to enhance light reflectivity. This mirror portion is formed by, for example, the following method. First, an inclined surface is formed on the core portion of the optical waveguide by applying a method of cutting with a dicing blade or a method of laser ablation. Thereafter, a mirror portion made of a metal layer is formed on the inclined surface by vapor deposition or sputtering.

  In addition, the formation of the electric circuit is generally performed separately from the formation of the optical waveguide. Specifically, first, before forming an optical waveguide, an electric circuit is formed on a substrate in advance, that is, an optical waveguide is formed on a printed wiring board on which an electric circuit is formed. The method of forming a composite wiring board is mentioned. Other methods include a method of bonding a printed wiring board on which an electric circuit is formed to a substrate on which an optical waveguide is formed. In addition, a method of forming an electric circuit on a substrate on which an optical waveguide is formed may be used.

  Apart from such a method of forming an electric circuit, forming an optical waveguide, particularly a mirror portion, is a wasteful process because the same process is performed a plurality of times.

  Patent Document 1 discloses that the manufacturing method can be simplified. However, in the method described in Patent Document 1, it is necessary to first form a groove on the substrate surface by pressing a press die on the substrate surface, so this method may not be applied depending on the type of the substrate. .

  Further, as described above, Patent Document 2 describes a method of forming and arranging a mirror member in advance before forming an optical waveguide. Patent Document 2 discloses that electrical wiring can be produced simultaneously with the formation of the mirror member. However, such a method is different from a method of forming a mirror portion in an optical waveguide when the optical waveguide is formed. In addition, it is necessary to form a mirror member in advance before forming the optical waveguide, and the manufacturing process becomes complicated, and this method may not be applied depending on the type of the substrate.

  The present invention has been made in view of such circumstances, and is capable of forming a mirror part made of a metal layer on the inclined surface of the core part at the same time as the formation of the electric circuit. It aims at providing the manufacturing method of an electrical composite wiring board. Another object of the present invention is to provide a photoelectric composite wiring board manufactured by the manufacturing method.

  An optical waveguide manufacturing method according to an aspect of the present invention includes a core part forming step of forming a core by forming a core on a surface of a first cladding layer formed on a substrate; The light incident from the side opposite to the side in contact with the first cladding layer is guided into the core portion or the light emitted from the core portion is opposite to the side in contact with the first cladding layer. At least the inclined surface forming step of forming an inclined surface for reflecting light on the core portion so as to be led to the side, and the surface of the laminated body on the side where the core portion is formed. A metal layer forming step of forming a metal layer on the surface and a portion where the electric circuit is formed, and removing the metal layer so that the metal layer remains on the inclined surface and the portion where the electric circuit is formed. And simultaneously with the formation of the electrical circuit, A metal layer removing step of forming a mirror portion made of the metal layer on an inclined surface; and a cladding layer forming step of forming a second cladding layer so as to embed a core portion formed on the first cladding layer. It is characterized by that.

  In addition, in the method for manufacturing an optical waveguide according to another aspect of the present invention, a cladding layer is formed by forming a second cladding layer so as to embed a core portion formed on the first cladding layer. Forming the light that is incident from the opposite side of the core portion that is in contact with the first cladding layer into the core portion, or the light that is emitted from the core portion with the first cladding layer. An inclined surface forming step for forming an inclined surface for reflecting light on the core portion so as to be led out to a side opposite to the contacting side, and the second cladding layer of the laminate is formed. A metal layer forming step of forming a metal layer at least on the inclined surface and at the location where the electric circuit is formed, and leaving the metal layer on the inclined surface and where the electric circuit is formed. By removing the metal layer, Te, simultaneously with the formation of the electric circuit, characterized in that it comprises a metal layer removing step of forming a mirror section consisting of said metal layer on the inclined surface.

  Further, in the method of manufacturing each photoelectric wiring board, after the metal layer removing step, at least on the mirror portion, a corrosion-resistant metal layer made of a corrosion-resistant metal that is less likely to corrode than the metal constituting the mirror portion. It is preferable to provide the process of forming.

  Moreover, in the manufacturing method of each said optoelectric wiring board, the process of roughening the surface by which the metal layer is formed in the said metal layer formation process of the said laminated body is provided before the said metal layer formation process. preferable.

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

  In the opto-electric composite wiring board, it is preferable that the mirror portion is made of copper and the corrosion-resistant metal layer is made of gold.

  In the photoelectric composite wiring board, it is preferable that the mirror part and the electric circuit have the same composition, and the mirror part and the electric circuit have the same thickness.

  According to the present invention, there is provided a method for manufacturing an opto-electric composite wiring board with high manufacturing efficiency such that a mirror part made of a metal layer can be formed on an inclined surface of a core part simultaneously with the formation of an electric circuit. be able to. Moreover, the photoelectric composite wiring board manufactured by the said manufacturing method is provided.

It is the schematic for demonstrating the manufacturing method of the photoelectric composite wiring board which concerns on 1st Embodiment of this invention. It is the schematic for demonstrating the manufacturing method of the photoelectric composite wiring board which concerns on 2nd Embodiment of this invention.

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

[First Embodiment]
The method for manufacturing an optical waveguide according to the first embodiment of the present invention includes a core part forming step of forming a core part on the surface of a first cladding layer formed on a substrate to form a laminate, and the core The side of the portion that is in contact with the first clad layer and the side that is in contact with the first clad layer. At least one of the inclined surface forming step for forming the inclined surface for reflecting the light on the core portion and the surface of the laminated body on the side on which the core portion is formed. A metal layer forming step of forming a metal layer on the inclined surface and a portion where the electric circuit is formed, and removing the metal layer so that the metal layer remains on the inclined surface and the portion where the electric circuit is formed. Simultaneously with the formation of the electrical circuit A metal layer removing step of forming a mirror portion made of the metal layer on the inclined surface, and a cladding layer forming step of forming a second cladding layer so as to embed a core portion formed on the first cladding layer; It is characterized by providing.

  By doing so, the mirror part which consists of a metal layer can be formed on the inclined surface of a core part simultaneously with formation of an electric circuit. Therefore, a photoelectric composite wiring board can be manufactured with high manufacturing efficiency.

  Specifically, first, an inclined surface is formed in the core portion in the inclined surface forming step, and in the metal layer forming step, a metal layer is formed so as to cover at least the portion where the inclined surface and the electric circuit are formed. A metal layer removing step of removing the metal layer is performed on the laminated body on which the metal layer is formed so that the metal layer remains on the inclined surface and at the location where the electric circuit is formed. By doing so, the mirror part which consists of the said metal layer can be formed on the said inclined surface simultaneously with formation of the said electric circuit. Therefore, it is considered that the manufacturing efficiency of the photoelectric composite wiring board is increased as compared with the case where the formation of the electric circuit and the formation of the mirror portion are performed separately.

  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 the core part formation process in 1st Embodiment. FIG.1 (b) is a schematic sectional drawing for demonstrating the inclined surface formation process in 1st Embodiment. FIG.1 (c) is the schematic for demonstrating the metal layer formation process in 1st Embodiment. 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 a metal layer removing step in the first embodiment. FIG.1 (f) is the schematic sectional drawing seen from the cut surface line ff of the laminated body shown in FIG.1 (e). FIG.1 (g) is the schematic for demonstrating the clad layer formation process in 1st Embodiment.

  As an optical waveguide manufacturing method according to the first embodiment of the present invention, first, as shown in FIG. 1A, a first cladding layer of a substrate 11 having a first cladding layer (lower cladding layer) 12 is used. A core portion 13 is formed on 12. This step corresponds to the core portion forming step.

  Specifically, first, the first cladding layer 12 is formed on the surface of the substrate 11.

  The substrate 11 used in the present embodiment is not particularly limited as long as it is used as a substrate for an optoelectric composite wiring board. Specifically, the substrate 11 may be an organic substrate or an inorganic substrate. Specific examples of the organic substrate include an epoxy substrate, an acrylic substrate, a polycarbonate substrate, and a polyimide substrate. Specific 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.

  A method for forming the first cladding layer 12 in the present embodiment is not particularly limited as long as the first cladding layer 12 can be formed on the surface of the substrate 11. Specifically, the following method is mentioned, for example. As a first example, there is a method in which a resin film made of a curable resin material having a predetermined refractive index for forming the first cladding layer 12 is bonded to the surface of the substrate 11 and then cured. Further, as a second example, there is a method in which a liquid curable resin material for forming the first cladding layer 12 is applied and then cured. As a third example, there is a method in which a varnish of a curable resin material for forming the first cladding layer 12 is applied and then cured. In addition, when forming the 1st clad layer 12, in order to improve adhesiveness, it is preferable to give a plasma process etc. to the surface of the board | substrate 11 previously.

  In addition, as a more specific method of curing after bonding the resin film to form the first cladding layer 12, for example, the following method is used. First, the 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 the resin film made of a curable resin is attached to the surface of the substrate 11 with a transparent adhesive. Match. And it hardens | cures by irradiating energy rays, such as light, to the bonded resin film, or heating.

  Further, as a more specific method of applying the liquid curable resin material or the varnish of the curable resin material for forming the first clad layer 12 and then curing it, for example, the following method 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 the varnish of the curable resin material is irradiated with energy rays such as light or is cured by heating.

  As the curable resin material for forming the first cladding layer 12, a material having a refractive index at the transmission wavelength of the guided light is lower than that of the material of the core portion 13 to be formed later. Specifically, the refractive index at the transmission wavelength is, for example, 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 such a refractive index.

  The curable resin material used when forming the first cladding layer 12 is not particularly limited as long as it can be used as a cladding layer that satisfies the above-described refractive index after curing. Specifically, for example, as described above, those that are cured by energy rays such as light or heat can be used. More specifically, a photosensitive material etc. are mentioned, for example. The resin film made of the curable resin material is specifically a dry film obtained by applying a semi-cured photosensitive polymer material to a polyethylene terephthalate (PET) film or the like, for example, a so-called dry film. Examples thereof include a photoresist (also simply referred to as “photosensitive film”).

  The thickness of the first cladding layer 12 is not particularly limited. Specifically, it is preferable that it is about 5-15 micrometers, for example.

  Next, a core material layer 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 method for forming the core material layer is not particularly limited as long as the core material layer can be formed. Specifically, the following method is mentioned, for example. As a first example, there is a method in which a resin film (photosensitive film) made of a photosensitive polymer material having a predetermined refractive index for forming a core material layer is bonded to the outer surface of the first cladding layer 12. Can be mentioned. As a second example, there is a method of applying a liquid photosensitive polymer material for forming a core material layer. As a third example, there is a method in which a varnish of a photosensitive polymer material for forming a core material layer is applied and then dried. In addition, when forming the core material layer, 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.

  As a more specific method of bonding the resin film to form the core material layer, for example, the following method is used. After placing the resin film made of a curable resin on the outer surface of the first cladding layer 12, the first clad layer 12 is bonded by a hot press.

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

  Examples of the resin film (photosensitive film) made of a photosensitive polymer material include a dry film obtained by applying a semi-cured photosensitive polymer material to a polyethylene terephthalate (PET) film or the like. Such a dry film is usually protected by a protective film.

  As the photosensitive polymer material for forming the core material layer, 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. Specifically, the refractive index at the transmission wavelength is, for example, about 1.55 to 1.6. As a kind of photosensitive polymer material for forming the core material layer, a photosensitive material having such a refractive index and having an epoxy resin, an acrylic resin, a polycarbonate resin, a polyimide resin, or the like as a resin component Is mentioned. Among these, bisphenol type epoxy resins are particularly preferable. Therefore, as a photosensitive polymer material for forming the core material layer, a resin composition containing a bisphenol-type epoxy resin and a photocationic curing agent can provide a highly heat-resistant waveguide. It is preferable because it can be combined with the above. From the viewpoint of adhesion between the core material layer and the first cladding layer 12, the photosensitive polymer material for forming the core material layer is the same as the curable resin material for forming the first cladding layer 12. It is preferable that it is a system | strain.

  The thickness of the core material layer is not particularly limited. Specifically, it is preferable that it is about 20-100 micrometers, for example.

  Before the core material layer is exposed and cured, the core material layer may be heat treated. By doing so, the irregularities, bubbles, voids, etc. on the surface of the core material layer 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 material layer disappear and become smooth, and is appropriately selected depending on the type of the curable resin material forming the core material layer. Further, the heat treatment time is preferably about 10 to 30 minutes from the viewpoint of sufficiently obtaining the effect of eliminating the irregularities, bubbles, voids and the like on the surface of the core material layer and smoothing. 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 material layer is irradiated with exposure light through a photomask to perform pattern exposure of a predetermined shape on the core material layer. Moreover, such exposure can be used without any limitation as long as it is a method of exposing light having a wavelength that can change (harden, etc.) the photosensitive material with light with a necessary amount of light. Specifically, for example, a method using energy rays such as ultraviolet rays can be used as the exposure light used here. In view of ease of handling, ultraviolet rays are preferably used. Also, contact exposure in which a photomask is placed so as to be in contact with the surface of the core material layer and exposure, projection type exposure in which exposure is performed while maintaining a predetermined interval so as not to be in contact with the outer surface of the core material layer, etc. Any of these exposure methods may be used.

The exposure conditions are appropriately selected according to the type of the photosensitive material. For example, conditions for exposure using an ultrahigh pressure mercury lamp to 500 to 3500 mJ / cm ² are selected.

  And after performing such 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. However, it is not particularly limited to this range, and it is needless to say that optimization by the photosensitive material is important.

  Next, a core portion 13 as shown in FIG. 1A is formed by performing development processing.

  As a development process for forming the core portion 13, when the photosensitive material of the core material layer is a positive type, the unexposed portion is washed away. When the negative photosensitive type is used, the exposed portion is washed away with a developer. This is a step of removing unnecessary portions. Examples of the developer used here include acetone, isopropyl alcohol, toluene, ethylene glycol, or a mixture of these in a predetermined ratio. Further, 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.

  Next, an inclined surface 15 a for reflecting light is formed on the core portion 13. This process corresponds to an inclined surface forming process. The method is not particularly limited as long as an inclined surface described later can be formed. The inclined surface here refers to the light that is incident from the side opposite to the side of the core 13 that is in contact with the first cladding layer 12, or the light that is emitted from the core 13 is guided into the core 13. 1 is an inclined surface for reflecting light so as to be led out to the side opposite to the side in contact with the cladding layer 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 portion 13 is cut to form the recess 15. That is, the blade 14 is suspended from the core portion 13 while being rotated so as to be substantially perpendicular to the core portion 13. At this time, the recess 15 guides light incident from the opposite side of the first cladding layer 12 into the core portion 13 or guides light emitted from the core portion 13 to the opposite side of the first cladding layer 12. The core portion 13 is cut so as to form a recess 15 having an inclined surface 15a for reflecting 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 part 13 with the blade 14, if necessary, the core part 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.

  Next, as shown in FIG. 1C, after the recess 15 is formed as described above, the core portion 13 of the laminate of the core portion 13, the first cladding layer 12, and the substrate 11 is formed. The metal layer 16 is formed at least on the inclined surface 15a and at the place where the electric circuit is formed in the surface on the side where the current is formed. This process corresponds to a metal layer forming process. The method for forming the metal layer 16 is not particularly limited, and a known method can be used. Specifically, for example, a plating method such as an electroless plating method or an electrolytic plating method, a vapor deposition method such as a vacuum vapor deposition method, a sputtering method, a nano paste method, or the like can be given.

  The thickness of the metal layer 16 is not particularly limited as long as it can reflect light. Specifically, for example, a thickness of about 1000 mm can be mentioned.

  Further, the place where the metal layer 16 is formed may be the entire surface of the laminated plate of the core portion 13, the first cladding layer 12 and the substrate 11 on the side where the core portion 13 is formed. What is necessary is just to form the metal layer 16 in the location which forms the electrical circuit at least on the inclined surface 15a of the laminated body surface of the core part 13, the 1st cladding layer 12, and the board | substrate 11. FIG. And it is preferable from the point which raises the manufacturing efficiency of a photoelectric composite wiring board to form a metal layer at the location which forms the electrical circuit at least on the inclined surface 15a of this laminated body surface. This means that in forming the metal layer 16, it is not necessary to form a metal layer on the entire surface of the laminated body of the core portion 13, the first cladding layer 12 and the substrate 11 on the side where the core portion 13 is formed. It depends. That is, it is considered that a desired photoelectric composite wiring board can be obtained if a metal layer is formed at least on the inclined surface 15a and at a location where an electric circuit is formed on the surface of the laminate.

  As described above, the metal layer 16 is formed not only on the surface of the core portion 13 but also on the portion where the electric circuit is formed. Specifically, as shown in FIG. 1C and FIG. 1D, the metal layer 16 is also formed at a location where the core portion 13 is not formed.

  In addition, before the metal layer 16 is formed, a roughening treatment may be performed to roughen the surface of the laminated body of the core portion 13, the first cladding layer 12, and the substrate 11 on the side on which the metal layer 16 is formed. . By doing so, the manufacturing efficiency of a photoelectric composite wiring board can be improved. This is considered to be because the metal layer 16 can be easily formed on the surface of the laminated body of the core portion 13, the first cladding layer 12, and the substrate 11. Furthermore, it is considered that the metal layer 16 formed here is difficult to peel from the surface of the laminate. That is, it is considered that a mirror portion 16a formed from the metal layer 16, which will be described later, is difficult to peel off from the inclined surface 15a. In addition, it is considered that an electric circuit 16b formed from the metal layer 16, which will be described later, is difficult to peel from the laminate. Moreover, it does not specifically limit as a roughening processing method. Specifically, for example, a microetching treatment such as a microetching treatment using a permanganic acid treatment solution can be mentioned.

  Next, as shown in FIG. 1E and FIG. 1F, the metal layer 16 in other portions is removed so that the metal layer 16 remains on the inclined surface 15a and where the electric circuit is formed. . By doing so, the mirror part 16a which consists of a metal layer can be formed on the inclined surface 15a simultaneously with formation of the electric circuit 16b. This process corresponds to a metal layer removing process. The method for removing the metal layer is not particularly limited as long as it is a method that can remove the metal layer 16 in other portions while leaving the metal layer 16 on the inclined surface 15a and where the electric circuit is formed. Specifically, the following method is mentioned, for example. First, a resist is applied to the entire surface of the metal layer 16. Thereafter, UV irradiation is performed through a photomask or the like so that only the resist on the inclined surface 15a and the portion where the electric circuit is formed is not removed by the development process. Then, by performing the development process, only the resist on the inclined surface 15a and the portion where the electric circuit is formed is left. 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 simultaneously with formation of the electric circuit 16b.

  Moreover, if the electric circuit 16b and the mirror part 16a are formed by such a method, the electric circuit 16b and the mirror part 16a can be formed simultaneously. Furthermore, the mirror part 16a and the electric circuit 16b have the same composition, and the mirror part 16a and the electric circuit 16b have the same thickness. This means that the obtained photoelectric composite wiring board has excellent mounting accuracy such as a light receiving element and a light emitting element.

  This is considered to be due to the following.

  First, when the difference in thickness between the mirror part and the electric circuit becomes large, when the surface on which the mirror part of the photoelectric composite wiring board is formed is viewed from a direction perpendicular to the surface direction of the photoelectric composite wiring board, The position of the mirror part with respect to the electric circuit tends to shift because the mirror part is inclined. For this reason, when mounting a light receiving element, light emitting element, etc. based on an alignment mark provided on the substrate, the light receiving element, light emitting element, etc. There is a tendency to deviate from the position. At this time, if the thickness of the mirror part and the electric circuit is the same, the occurrence of such a shift can be suppressed, and an opto-electric composite wiring board with excellent mounting accuracy such as a light receiving element or a light emitting element can be obtained. It is done.

  Moreover, after forming the electric circuit 16b and the mirror part 16a, it is preferable to form the corrosion-resistant metal layer which consists of a corrosion-resistant metal which is harder to corrode than the metal which comprises the mirror part 16a at least on the mirror part 16a. By doing so, a highly reliable optoelectric wiring board can be manufactured. Furthermore, in the obtained photoelectric circuit board, a highly corrosion-resistant metal layer having high adhesion can be obtained.

  Specifically, it is considered as follows.

  First, by forming a corrosion-resistant metal layer made of a corrosion-resistant metal that is harder to corrode than the metal constituting the mirror portion on the mirror portion, the corrosion-resistant metal layer is free from corrosion such as rust. It is thought that it can be suppressed. From this, it is thought that it can suppress that the reflectance fall of the light in the said corrosion-resistant metal layer by the corrosion of the said corrosion-resistant metal layer occurs. Therefore, it is considered that the obtained photoelectric circuit board has high reliability. Further, as the corrosion-resistant metal layer, for example, by using a layer made of gold or the like, it is possible to realize a high reflectance with respect to light, and further, a decrease in reflectance due to corrosion of the corrosion-resistant metal layer. Can be suppressed.

  Next, rather than forming a corrosion-resistant metal layer, for example, a gold layer, directly on the inclined surface, a metal layer, for example, a copper layer, constituting the mirror portion formed simultaneously with the electric wiring is interposed. Thus, it is considered that the adhesion of the corrosion-resistant metal layer is enhanced when the corrosion-resistant metal layer is formed. Therefore, according to such a method, it is thought that the corrosion-resistant metal layer that can improve the reliability of the photoelectric circuit board can be formed on the inclined surface with high adhesion.

  Moreover, it is preferable that the mirror part 16a consists of copper, and a corrosion-resistant metal layer consists of gold. By doing so, since the corrosion-resistant metal layer formed on the inclined surface 15a via the mirror portion 16a is made of gold, a highly reliable photoelectric composite wiring board can be obtained. Further, since the corrosion-resistant metal layer made of gold is formed through the mirror part made of copper, the photoelectricity having higher adhesion than the case where the corrosion-resistant metal layer made of gold is directly formed on the inclined surface. A composite wiring board is obtained.

  Finally, as shown in FIG. 1 (g), the second cladding layer (upper cladding layer) 17 is formed so as to embed the core portion 13 formed as described above, whereby the optical waveguide is formed. The photoelectric composite wiring board 18 provided is formed. This process corresponds to a cladding layer forming process.

  A method for forming the second cladding layer 17 is not particularly limited. Specific examples include the following methods. As a first example, there is a method in which a liquid curable resin material for forming the second cladding layer 17 is applied so as to embed the core portion 13 and then cured by energy rays such as light, heat, or the like. Can be mentioned. As a second method, there is a method in which a varnish of a curable resin material for forming the second cladding layer 17 is applied and then cured by energy rays such as light, heat or the like. As a third example, there is a method in which a resin film made of a curable resin material for forming the second cladding layer 17 is bonded and then cured by energy rays such as light, heat or the like.

  The curable resin material for forming the second cladding 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 guided light than the material of the core portion 13. Usually, the same kind of curable resin material as that used to form the first cladding layer 12 is used.

  In addition, the thickness of the second cladding layer 17 is not particularly limited, but it is preferable that the thickness of the second cladding layer 17 is approximately the same as that of the first cladding layer 12 on the core portion 13.

  Through the steps as described above, the photoelectric composite wiring board 18 having the optical waveguide as shown in FIG. 1G is formed. In addition, the arrow in FIG.1 (g) shows the optical path of the waveguide light which injects into an optical waveguide and is radiate | emitted.

  The formed optical waveguide is formed by the core portion 13 and the cladding layers covering the core portion 13 (the first cladding layer 12 and the second cladding layer 17). The core portion 13 has a higher refractive index than the cladding layer. The 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 portion 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 17 excluding the thickness of the layer including the core portion is 5 to 5, respectively. The refractive index difference between the core portion and the cladding layer is suitably about 0.5 to 3%, but is not limited to this.

  As described above, such a manufacturing method can form the mirror portion and the electric circuit at the same time, and has high manufacturing efficiency of the photoelectric composite wiring board.

[Second Embodiment]
The optical waveguide manufacturing method according to the second embodiment of the present invention includes a clad layer forming step in which a second clad layer is formed so as to embed a core portion formed on the first clad layer to form a laminate. And guiding the light incident from the side opposite to the side of the core part in contact with the first cladding layer into the core part or contacting the light emitted from the core part with the first cladding layer. An inclined surface forming step for forming an inclined surface for reflecting light on the core portion so as to be led out to the side opposite to the side on which the second cladding layer is formed, and the side of the laminate on which the second cladding layer is formed A metal layer forming step of forming a metal layer at least on the inclined surface and a portion where an electric circuit is formed, and leaving the metal layer on the inclined surface and a portion where an electric circuit is formed, By removing the metal layer, Simultaneously with the formation of an electrical circuit, characterized in that it comprises a metal layer removing step of forming a mirror section consisting of said metal layer on the inclined surface.

  By doing so, the mirror part which consists of a metal layer can be formed on the inclined surface of a core part simultaneously with formation of an electric circuit. Therefore, a photoelectric composite wiring board can be manufactured with high manufacturing efficiency.

  Specifically, first, an inclined surface is formed in the core portion in the inclined surface forming step, and in the metal layer forming step, a metal layer is formed so as to cover at least the portion where the inclined surface and the electric circuit are formed. A metal layer removing step of removing the metal layer is performed on the laminated body on which the metal layer is formed so that the metal layer remains on the inclined surface and at the location where the electric circuit is formed. By doing so, the mirror part which consists of the said metal layer can be formed on the said inclined surface simultaneously with formation of the said electric circuit. Therefore, it is considered that the manufacturing efficiency of the photoelectric composite wiring board is increased as compared with the case where the formation of the electric circuit and the formation of the mirror portion are performed separately.

  In the clad layer forming step, after forming the second clad layer so as to embed a core portion formed on the first clad layer, the inclined surface forming step, the metal layer forming step, and the metal layer Since the removal step is performed, it is considered that almost no metal, resist, or the like remains on the surface of the core portion.

  FIG. 2 is a schematic view for explaining a method for manufacturing an optoelectric composite wiring board according to the second embodiment of the present invention. FIG. 2A is a schematic cross-sectional view for explaining the core portion formed on the first cladding layer in the second embodiment. FIG. 2B is a schematic cross-sectional view for explaining a cladding layer forming step in the second embodiment. FIG. 2C is a schematic cross-sectional view for explaining an inclined surface forming step in the second embodiment. FIG. 2D is a schematic view for explaining a metal layer forming step in the second embodiment. FIG. 2E is a schematic view for explaining the metal layer removing step in the second embodiment.

  As a method for manufacturing an optical waveguide according to the second embodiment of the present invention, first, as shown in FIG. 2A, the first cladding layer of the substrate 11 provided with the first cladding layer (lower cladding layer) 12 is used. A core portion 13 is formed on 12. As this formation method, the same method as the formation of the core portion 13 in the first embodiment can be mentioned.

  Next, as shown in FIG. 2B, a second clad layer 17 is formed so as to embed the core portion 13 formed on the first clad layer 12, and a laminated body is formed. Examples of the formation method include the same method as the formation of the second cladding layer 17 in the first embodiment. The difference from the first embodiment is that the second cladding layer 17 is formed before the inclined surface or the like is formed in the core portion 13 to be embedded.

  Next, an inclined surface for reflecting light is formed on the laminate of the first cladding layer 12, the core portion 13, the second cladding layer 17, and the substrate 11. This process corresponds to an inclined surface forming process. As the method, the same method as the formation of the inclined surface in the first embodiment can be mentioned. Specifically, as in the first embodiment, as shown in FIG. 2C, one surface of the blade edge is a surface parallel to the blade surface direction, and the other surface is an angle with respect to the blade surface direction. Is formed by cutting the laminate of the first cladding layer 12, the core portion 13, the second cladding layer 17, and the substrate 11 by using a blade 14 having a predetermined angle, for example, 45 °. The method of doing is mentioned. The difference from the first embodiment is that not only the core portion 13 but also the second cladding layer 17 is cut.

  Next, as shown in FIG. 2 (d), after the recess 15 is formed as described above, the laminate of the first cladding layer 12, the core portion 13, the second cladding layer 17, and the substrate 11 is formed. Of the surface on the side where the second cladding layer 17 is formed, the metal layer 16 is formed at least on the inclined surface 15a and at a location where an electric circuit is formed. This process corresponds to a metal layer forming process. As the method, the same method as the formation of the metal layer in the first embodiment can be mentioned.

  Next, as shown in FIG. 2E, other portions of the metal layer are removed so that the metal layer 16 remains on the inclined surface 15a and at the place where the electric circuit is formed. By doing so, the mirror part 16a which consists of a metal layer can be formed on the inclined surface 15a simultaneously with formation of the electric circuit 16b. This process corresponds to a metal layer removing process. Examples of the method for removing the metal layer include the same method as the method for removing the metal layer in the first embodiment.

  Through the steps as described above, the photoelectric composite wiring board 18 having the optical waveguide as shown in FIG. 2E is formed. In addition, the arrow in FIG.2 (e) shows the optical path of the waveguide light which injects into an optical waveguide and is radiate | emitted.

  As described above, such a manufacturing method can form the mirror portion and the electric circuit at the same time, and has high manufacturing efficiency of the photoelectric composite wiring board.

  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.

  First, a method for producing the resin film used in this example will be described.

(Manufacture of resin film for lower cladding layer)
Epoxy resin (EHPE 3150 manufactured by Daicel Chemical Industries, Ltd., 62 parts by mass of 1,2-epoxy-4- (2-oxiranyl) cyclosoxane adduct of 2,2-bis (hydroxymethyl) -1-butanol), liquid bisphenol 12 parts by mass of A-type epoxy resin (Epiclon 850s manufactured by DIC Corporation), 18 parts by mass of phenoxy resin (YP50 manufactured by Nippon Steel Chemical Co., Ltd.), trimethylolpropane type epoxy resin (Epototo manufactured by Nippon Steel Chemical Co., Ltd.) YH300) 8 parts by mass, photocationic curing initiator (SP-170 manufactured by Adeka Co., Ltd.) 0.5 part by mass, thermal cationic curing initiator (SI-150L manufactured by Sanshin Chemical Industry Co., Ltd.) 0.5 part by mass , 0.1 parts by mass of each surface preparation agent (F470 manufactured by DIC Corporation), 30 parts by mass of toluene and MEK70 quality It was dissolved in a mixed solvent with an amount of part. The solution was filtered through a membrane filter having a pore size of 1 μm and then degassed under reduced pressure. By doing so, an epoxy resin varnish was prepared. The prepared varnish was applied to a PET film (A4100 manufactured by Toyobo Co., Ltd.) using a comma coater head multi coater manufactured by Hirano Techseed Co., Ltd. and dried to obtain a resin layer having a predetermined thickness. On the resin layer, OPP-MA420 manufactured by Oji Specialty Paper Co., Ltd. was thermally laminated as a release film. By doing so, the resin film for lower clad layers was obtained. The thickness of the obtained resin film for lower clad layers was 10 μm.

(Manufacture of resin film for core part)
3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate (Celoxide 2021P (also referred to as CEL2021P) manufactured by Daicel Chemical Industries, Ltd.) 8 parts by mass, epoxy resin (EHPE3150 manufactured by Daicel Chemical Industries, Ltd.) 1,2-epoxy-4- (2-oxiranyl) cyclosoxane adduct of 2,2-bis (hydroxymethyl) -1-butanol), 12 parts by mass of solid bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation) Epicoat 1006FS) 37 parts by mass, trifunctional epoxy resin (VG-3101 made by Mitsui Chemicals) 15 parts by mass, solid novolac type epoxy resin (EPPN201 made by Nippon Kayaku Co., Ltd.) 18 parts by mass, liquid bisphenol A type epoxy Resin (Epic manufactured by DIC Corporation 850 s) 10 parts by weight, 1 part by weight of a cationic photocuring initiator (SP-170 manufactured by Adeka Co., Ltd.), and 0.1 parts by weight of a surface conditioner (F470 manufactured by DIC Corporation) were mixed with toluene 30. It was dissolved in a mixed solvent of parts by mass and 70 parts by mass of MEK. The solution was filtered through a membrane filter having a pore size of 1 μm and then degassed under reduced pressure. By doing so, an epoxy resin varnish was prepared. The prepared varnish was applied to a PET film (A4100 manufactured by Toyobo Co., Ltd.) using a comma coater head multi coater manufactured by Hirano Techseed Co., Ltd. and dried to obtain a resin layer having a predetermined thickness. On the resin layer, OPP-MA420 manufactured by Oji Specialty Paper Co., Ltd. was thermally laminated as a release film. By doing so, the resin film for core parts was obtained. The thickness of the obtained resin film for a core part was 40 μm.

(Manufacture of resin film for upper cladding layer)
An upper clad layer resin film was produced in the same manner as the upper clad layer resin film except that the thickness was changed to 50 μm.

Example 1
Example 1 is an example according to the first embodiment.

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, a resin film for a lower 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 lower 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 lower 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 lower clad layers hardened was formed on the substrate.

  Next, on the surface of the lower clad layer, the 40 μm-thick core portion resin film produced 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, the resin varnish used in the production of the resin film for the lower clad layer was diluted by a factor of 50 with a mixed solvent in which toluene and MEK were mixed at a mass ratio of 3: 7. Apply thinly with a brush. 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. Thereafter, a cleaner conditioning process, a soft etching process, a pre-dip process, a catalyst process, an accelerator process, and an electroless copper plating process were further performed. By doing so, the metal thin layer which consists of electroless copper plating was formed. Then, a degreasing process, an acid activation process, an electrolytic copper plating process, and a rust prevention process were performed. By doing so, as shown in FIG.1 (c) and FIG.1 (d), the metal layer which consists of about 30 micrometers copper was formed.

  Next, a resist was applied to the metal layer, and ultraviolet (UV) treatment was performed so that the resist remained on a 45 ° inclined surface, which is a place where an electric circuit is formed and a place where a mirror part is formed. Thereafter, the resist was developed by performing a resist development step. By doing so, the resist remained on the 45 ° inclined surface, which is the place where the electric circuit is formed and the place where the mirror portion is formed. In this state, after performing the etching process which etches copper, the resist peeling process was performed. By doing so, a mirror part made of copper was formed on a 45 ° inclined surface at the same time as the electric circuit was formed. Furthermore, after forming a solder resist, gold plating treatment was performed. By doing so, a layer made of gold having high reflection efficiency was formed on the mirror portion. At that time, if necessary, a layer made of gold was also disposed on the electric circuit.

Next, as shown in FIG. 1 (g), a resin film for an upper clad layer having a thickness of 50 μm produced by the above-described method so as to cover the lower clad layer and the core portion is formed by using a vacuum laminator (V-130). ) Was used under the conditions of 80 ° C. and 0.3 MPa. And the ultraviolet light was irradiated to the resin film for upper clad layers on the conditions of ² J / cm < ² > using the ultra high pressure mercury lamp. Thereafter, the release film of the resin film for the upper clad layer was peeled off. Thereafter, heat treatment was performed at 150 ° C. for 60 minutes. By doing so, the 2nd clad layer (upper clad layer) was formed so that a lower clad layer and a core part might be covered. That is, as shown in FIG. 1G, an optoelectric composite wiring board in which an optical waveguide composed of a lower cladding layer, a core portion, and an upper cladding layer was formed was formed. The upper clad layer only needs to cover the core portion and the lower clad layer around the core portion.

  The following evaluation was performed on the formed optical waveguide.

(Waveguide loss measurement)
The input side end, specifically, the surface of the second cladding layer in the direction perpendicular to the second cladding layer at the position where one mirror is formed (or the end of the optical waveguide is exposed). In this case, the end of an optical fiber having a core diameter of 10 μm and NA of 0.21 was connected to one end surface of the core via matching oil (silicone oil). And the output side end, specifically, the surface of the second cladding layer in the direction perpendicular to the second cladding layer at the position where the other mirror is formed (or the end of the optical waveguide) Is exposed, the other end face of the core portion is connected to the end of an optical fiber having a core diameter of 200 μm and NA of 0.4 via matching oil. The light from the 850 nm VCSEL light source was made incident on the optical waveguide through the optical fiber connected to the input side end. Then, the emitted light from the optical waveguide was made incident on the power meter through the optical fiber connected to the output side end, and the light quantity P1 of the emitted light was measured.

  On the other hand, when the optical fiber connected to the input side end and the optical fiber connected to the output side end are directly connected without going through the optical waveguide, the output from the optical fiber connected to the output side end The amount of incident light P0 was measured in the same manner as described above.

  Then, the insertion loss L1 of the optical waveguide is obtained by the following formula (1), and this insertion loss L1 is defined as the waveguide loss.

L1 = -10 log (P1 / P0) (1)
When the above evaluation was performed on the optical waveguide obtained in Example 1, the waveguide loss was 2.7 dB. From this, it was found that a practical photoelectric composite wiring board was manufactured.

  From the above, according to the manufacturing method according to Example 1, it was found that the mirror part could be formed simultaneously with the formation of the electric circuit, and that a practical photoelectric composite wiring board was manufactured. . From this, it was found that a practical photoelectric composite wiring board can be manufactured with high manufacturing efficiency.

(Example 2)
Example 2 is an example according to the second embodiment.

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, a resin film for a lower 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 lower 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 lower 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 lower clad layers hardened was formed on the substrate.

  Next, on the surface of the lower clad layer, the 40 μm-thick core portion resin film produced 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.2 (a) was formed.

Next, as shown in FIG. 2 (b), a resin film for an upper clad layer having a thickness of 50 μm produced by the above-described method so as to cover the lower clad layer and the core portion is formed using a vacuum laminator (V-130). ) Was used under the conditions of 80 ° C. and 0.3 MPa. And the ultraviolet light was irradiated to the resin film for upper clad layers on the conditions of ² J / cm < ² > using the ultra high pressure mercury lamp. Thereafter, the release film of the resin film for the upper clad layer was peeled off. Thereafter, heat treatment was performed at 150 ° C. for 60 minutes. The upper clad layer only needs to cover the core portion and the lower clad layer around the core portion.

  Next, as shown in FIG. 2C, 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 the both ends of the core portion is 2 I cut it. By doing so, as shown in FIG.2 (c), the recessed part which has a 45 degree inclined surface was formed so that a core part might be cut | disconnected completely. At this time, the upper clad layer is also cut together with the core portion.

Next, the resin varnish used in the production of the resin film for the lower clad layer was diluted by a factor of 50 with a mixed solvent in which toluene and MEK were mixed at a mass ratio of 3: 7. Apply thinly with a brush. 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 step, a permanganate treatment step, and a reduction treatment step were performed on the inclined surface of the core portion and the upper clad layer. By doing so, the inclined surface of the core part and the surface of the upper cladding layer were etched, and irregularities were formed on the surface. Thereafter, a cleaner conditioning process, a soft etching process, a pre-dip process, a catalyst process, an accelerator process, and an electroless copper plating process were further performed. By doing so, the metal thin layer which consists of electroless copper plating was formed. Then, a degreasing process, an acid activation process, an electrolytic copper plating process, and a rust prevention process were performed. By doing so, as shown in FIG.2 (d), the metal layer which consists of about 30 micrometers copper was formed.

  Next, a resist was applied to the metal layer, and ultraviolet (UV) treatment was performed so that the resist remained on a 45 ° inclined surface, which is a place where an electric circuit is formed and a place where a mirror part is formed. Thereafter, the resist was developed by performing a resist development step. By doing so, the resist remained on the 45 ° inclined surface, which is the place where the electric circuit is formed and the place where the mirror portion is formed. In this state, after performing the etching process which etches copper, the resist peeling process was performed. By doing so, a mirror part made of copper was formed on a 45 ° inclined surface at the same time as the electric circuit was formed. Furthermore, after forming a solder resist, gold plating treatment was performed. By doing so, a layer made of gold having high reflection efficiency was formed on the mirror portion. At that time, if necessary, a layer made of gold was also disposed on the electric circuit.

  Through the above process, as shown in FIG. 2E, an optoelectric composite wiring board in which an optical waveguide composed of a lower clad layer, a core portion, and an upper clad layer was formed was formed.

  About the formed optical waveguide, the waveguide loss measurement similar to Example 1 was performed. As a result, the waveguide loss of the optical waveguide obtained in Example 2 was 2.7 dB. From this, it was found that a practical photoelectric composite wiring board was manufactured.

  From the above, according to the manufacturing method according to Example 2, it was found that the mirror part could be formed simultaneously with the formation of the electric circuit, and that a practical photoelectric composite wiring board was manufactured. . From this, it was found that a practical photoelectric composite wiring board can be manufactured with high manufacturing efficiency.

  As described above, the present specification discloses various modes of technology, of which the main technologies are summarized below.

  An optical waveguide manufacturing method according to an aspect of the present invention includes a core part forming step of forming a core by forming a core on a surface of a first cladding layer formed on a substrate; The light incident from the side opposite to the side in contact with the first cladding layer is guided into the core portion or the light emitted from the core portion is opposite to the side in contact with the first cladding layer. At least the inclined surface forming step of forming an inclined surface for reflecting light on the core portion so as to be led to the side, and the surface of the laminated body on the side where the core portion is formed. A metal layer forming step of forming a metal layer on the surface and a portion where the electric circuit is formed, and removing the metal layer so that the metal layer remains on the inclined surface and the portion where the electric circuit is formed. And simultaneously with the formation of the electrical circuit, A metal layer removing step of forming a mirror portion made of the metal layer on an inclined surface; and a cladding layer forming step of forming a second cladding layer so as to embed a core portion formed on the first cladding layer. It is characterized by that.

  According to such a configuration, a method of manufacturing a photoelectric composite wiring board with high manufacturing efficiency, such as the ability to form a mirror part made of a metal layer on the inclined surface of the core part simultaneously with the formation of the electric circuit. Can be provided.

  Specifically, first, an inclined surface is formed in the core portion in the inclined surface forming step, and in the metal layer forming step, a metal layer is formed so as to cover at least the portion where the inclined surface and the electric circuit are formed. A metal layer removing step of removing the metal layer is performed on the laminated body on which the metal layer is formed so that the metal layer remains on the inclined surface and at the location where the electric circuit is formed. By doing so, the mirror part which consists of the said metal layer can be formed on the said inclined surface simultaneously with formation of the said electric circuit. Therefore, it is considered that the manufacturing efficiency of the photoelectric composite wiring board is increased as compared with the case where the formation of the electric circuit and the formation of the mirror portion are performed separately.

  In addition, in the method for manufacturing an optical waveguide according to another aspect of the present invention, a cladding layer is formed by forming a second cladding layer so as to embed a core portion formed on the first cladding layer. Forming the light that is incident from the opposite side of the core portion that is in contact with the first cladding layer into the core portion, or the light that is emitted from the core portion with the first cladding layer. An inclined surface forming step for forming an inclined surface for reflecting light on the core portion so as to be led out to a side opposite to the contacting side, and the second cladding layer of the laminate is formed. A metal layer forming step of forming a metal layer at least on the inclined surface and at the location where the electric circuit is formed, and leaving the metal layer on the inclined surface and where the electric circuit is formed. By removing the metal layer, Te, simultaneously with the formation of the electric circuit, characterized in that it comprises a metal layer removing step of forming a mirror section consisting of said metal layer on the inclined surface.

  According to such a configuration, a method of manufacturing a photoelectric composite wiring board with high manufacturing efficiency, such as the ability to form a mirror part made of a metal layer on the inclined surface of the core part simultaneously with the formation of the electric circuit. Can be provided.

  Specifically, first, an inclined surface is formed in the core portion in the inclined surface forming step, and in the metal layer forming step, a metal layer is formed so as to cover at least the portion where the inclined surface and the electric circuit are formed. A metal layer removing step of removing the metal layer is performed on the laminated body on which the metal layer is formed so that the metal layer remains on the inclined surface and at the location where the electric circuit is formed. By doing so, the mirror part which consists of the said metal layer can be formed on the said inclined surface simultaneously with formation of the said electric circuit. Therefore, it is considered that the manufacturing efficiency of the photoelectric composite wiring board is increased as compared with the case where the formation of the electric circuit and the formation of the mirror portion are performed separately.

  In the clad layer forming step, after forming the second clad layer so as to embed a core portion formed on the first clad layer, the inclined surface forming step, the metal layer forming step, and the metal layer Since the removal step is performed, it is considered that almost no metal, resist, or the like remains on the surface of the core portion.

  Further, in the method of manufacturing each photoelectric wiring board, after the metal layer removing step, at least on the mirror portion, a corrosion-resistant metal layer made of a corrosion-resistant metal that is less likely to corrode than the metal constituting the mirror portion. It is preferable to provide the process of forming.

  According to such a configuration, a highly reliable optoelectric wiring board can be manufactured. Moreover, in the obtained opto-electrical wiring board, one having high adhesion of the corrosion-resistant metal layer is obtained.

  Specifically, it is considered as follows.

  First, by forming a corrosion-resistant metal layer made of a corrosion-resistant metal that is harder to corrode than the metal constituting the mirror portion on the mirror portion, the corrosion-resistant metal layer can cause corrosion such as rust. It is thought that it can be suppressed. From this, it is thought that it can suppress that the reflectance fall of the light in the said corrosion-resistant metal layer by the corrosion of the said corrosion-resistant metal layer occurs. Therefore, it is considered that the obtained photoelectric circuit board has high reliability. Further, as the corrosion-resistant metal layer, for example, by using a layer made of gold or the like, it is possible to realize a high reflectance with respect to light, and further, a decrease in reflectance due to corrosion of the corrosion-resistant metal layer. Can be suppressed.

  Next, rather than forming a corrosion-resistant metal layer, for example, a gold layer, directly on the inclined surface, a metal layer, for example, a copper layer, constituting the mirror portion formed simultaneously with the electric wiring is interposed. Thus, it is considered that the adhesion of the corrosion-resistant metal layer is enhanced when the corrosion-resistant metal layer is formed. Therefore, according to such a method, it is thought that the corrosion-resistant metal layer that can improve the reliability of the photoelectric circuit board can be formed on the inclined surface with high adhesion.

  Moreover, in the manufacturing method of each said optoelectric wiring board, the process of roughening the surface by which the metal layer is formed in the said metal layer formation process of the said laminated body is provided before the said metal layer formation process. preferable.

  According to such a structure, the manufacturing method of a photoelectric composite wiring board with higher manufacturing efficiency can be provided. This is considered to be because a metal layer can be easily formed on the surface of the laminate. Furthermore, it is considered that the metal layer is difficult to peel from the surface of the laminate. That is, it is considered that the mirror part is difficult to peel from the inclined surface, and the electric circuit is difficult to peel from the laminate.

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

  According to such a configuration, an optoelectric composite wiring board including an optical waveguide having a mirror portion formed on an inclined surface having a predetermined angle and an electric circuit is obtained. In addition, as the inclined surface, the light incident from the opposite side (second cladding layer side) of the first cladding layer is guided into the core portion or the light emitted from the core portion is opposite to the first cladding layer. A photoelectric composite wiring board having an optical waveguide formed with an inclined surface capable of reflecting light so as to be led out to the side (second clad layer side) is obtained.

  In the opto-electric composite wiring board, it is preferable that the mirror portion is made of copper and the corrosion-resistant metal layer is made of gold.

  According to such a structure, since the said corrosion-resistant metal layer formed via the said mirror part on the said inclined surface consists of gold | metal | money, a highly reliable photoelectric composite wiring board is obtained. Further, since the corrosion-resistant metal layer made of gold is formed through the mirror part made of copper, the photoelectricity having higher adhesion than the case where the corrosion-resistant metal layer made of gold is directly formed on the inclined surface. A composite wiring board is obtained.

  In the photoelectric composite wiring board, it is preferable that the mirror part and the electric circuit have the same composition, and the mirror part and the electric circuit have the same thickness.

  According to such a configuration, a photoelectric composite wiring board having excellent mounting accuracy such as a light receiving element and a light emitting element can be obtained.

  This is considered to be due to the following.

  First, when the difference in thickness between the mirror portion and the electric circuit becomes large, the surface of the photoelectric composite wiring board on which the mirror portion is formed is viewed from a direction perpendicular to the surface direction of the photoelectric composite wiring board. When viewed, the position of the mirror part with respect to the electric circuit tends to shift because the mirror part is inclined. Therefore, when mounting a light receiving element or a light emitting element based on an alignment mark or the like provided on the substrate, even if the light receiving element or the light emitting element is to be mounted in accordance with the position where the mirror portion is formed, There is a tendency to deviate from a predetermined position. At this time, if the mirror part and the electric circuit have the same thickness, the occurrence of such a shift can be suppressed, and an opto-electric composite wiring board with excellent mounting accuracy such as a light receiving element or a light emitting element can be obtained. it is conceivable that.

11 Substrate 12 First cladding layer (lower cladding layer)
13 core part 14 blade (dicing blade)
15 Recessed portion 15a Inclined surface 16 Metal layer 16a Mirror portion 17 Second cladding layer (upper cladding layer)
18 Opto-electric composite wiring board

Claims (7)

Forming a core on the surface of the first cladding layer formed on the substrate to form a laminated body; and
The light incident from the side opposite to the side in contact with the first cladding layer of the core part is guided into the core part or the light emitted from the core part is in contact with the first cladding layer. An inclined surface forming step for forming an inclined surface for reflecting light on the core portion so as to be led out to the side opposite to the side;
A metal layer forming step of forming a metal layer at least on the inclined surface and at a place where an electric circuit is formed, of the surface of the laminated body on which the core portion is formed;
A mirror made of the metal layer on the inclined surface at the same time as the electric circuit is formed by removing the metal layer so that the metal layer remains on the inclined surface and where the electric circuit is formed. A metal layer removing step for forming a portion;
And a clad layer forming step of forming a second clad layer so as to embed a core part formed on the first clad layer. A clad layer forming step of forming a second clad layer so as to embed a core portion formed on the first clad layer, and forming a laminate;
The light incident from the side opposite to the side in contact with the first cladding layer of the core part is guided into the core part or the light emitted from the core part is in contact with the first cladding layer. An inclined surface forming step for forming an inclined surface for reflecting light on the core portion so as to be led out to the side opposite to the side;
A metal layer forming step of forming a metal layer at least on the inclined surface and at a location where an electric circuit is formed, of the surface of the laminate on the side where the second cladding layer is formed;
A mirror made of the metal layer on the inclined surface at the same time as the electric circuit is formed by removing the metal layer so that the metal layer remains on the inclined surface and where the electric circuit is formed. And a metal layer removing step for forming the portion.   The said metal layer removal process WHEREIN: The process of forming the corrosion-resistant metal layer which consists of a corrosion-resistant metal which is harder to corrode than the metal which comprises the said mirror part at least on the said mirror part is provided. The manufacturing method of the opto-electric composite wiring board as described in 1.   The photoelectric of any one of Claims 1-3 provided with the process of roughening the surface by which the metal layer is formed in the said metal layer formation process of the said laminated body before the said metal layer formation process. A method of manufacturing a composite wiring board.   An opto-electric composite wiring board obtained by the method for manufacturing an opto-electric composite wiring board according to any one of claims 1 to 4. The mirror part is made of copper,
The photoelectric composite wiring board according to claim 5, wherein the corrosion-resistant metal layer is made of gold. The mirror part and the electric circuit have the same composition,
The photoelectric composite wiring board according to claim 5 or 6, wherein the mirror part and the electric circuit have the same thickness.

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