JP5378172B2 - Optical waveguide core manufacturing method, optical waveguide manufacturing method, optical waveguide, and photoelectric composite wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of fabricating optical waveguide core, efficiently fabricating an optical waveguide core having inclined surfaces of a prescribed angle, and selectively forming a metal film on the inclined surface. <P>SOLUTION: The method of fabricating optical waveguide core includes: a core part forming step of forming a core part 13 on the surface of a clad layer 12 formed on a substrate 11; a recessed part forming step of forming a vertical surface 15a substantially vertical to a glad layer 12 and a recessed part 15 disposed opposite the vertical surface 15a having inclined surfaces 15b for reflecting light, which has vertical surfaces 15a substantially vertical to the clad layer 12 for reflecting light so as to guide light made incident from the opposite side of the clad layer 12 into the core part 13 or make light emitted from the core part 13 effluent to the opposite side; a metal layer forming step of forming a metal layer 16 on the recessed part 15; and a metal layer removing step of leaving a metal layer 16b at least on the inclined surface 15b by selectively removing a metal layer 16a formed on the vertical surface 15a. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an optical waveguide core manufacturing method, an optical waveguide manufacturing method, an optical waveguide manufactured by the optical waveguide manufacturing method, and an optoelectric composite wiring board including the optical waveguide.

  An opto-electric composite wiring board, which is a printed circuit board with a built-in optical waveguide that guides light inside, as a solution to high-frequency noise accompanying the speed-up of signals in various information processing devices and the shortage of transmission bandwidth. Is attracting attention.

  In such an opto-electric composite wiring board, an inclined surface capable of reflecting light on the core portion of the optical waveguide for the purpose of bending light to a desired angle, for example, to input / output light from the optical waveguide Is formed. Examples of a method for manufacturing an optical waveguide having such an inclined surface include the methods described in Non-Patent Document 1 and Patent Document 1.

  Non-Patent Document 1 describes the following manufacturing method as a method of manufacturing an optical waveguide. First, a photosensitive material layer is formed on the surface of the first cladding layer formed on the temporary substrate, and the photosensitive material layer is selectively exposed to form the core portion of the optical waveguide. And by processing the core part with a rotary blade or the like, an inclined surface for reflecting light is formed on the core, and a metal layer is formed on the inclined surface in order to improve the reflection efficiency of the inclined surface. Form. Thereafter, a second cladding layer is formed so as to embed the core portion on which the metal layer is formed. By doing so, an optical waveguide is formed on the temporary substrate. Finally, the substrate on which the optical waveguide was originally intended to be formed is attached to the second cladding layer of the formed optical waveguide, and the temporary substrate is peeled off.

  In Patent Document 1, a first step of forming a core part having a higher refractive index on the lower clad layer by patterning and an etching rate of the entire surface of the substrate with respect to both the core part and the lower clad layer or A second step of coating with a material layer for forming a different optical path bending means made of a developer solution, and an end face (inclined face) facing the end face of the core portion at a predetermined angle by patterning the material layer And a fourth step of forming an embedded optical waveguide by covering the entire surface of the substrate with an upper clad layer. A manufacturing method is described.

JP 2000-47044 A

Matsushita Electric Engineering Technical Report, Vol. 54, no. 3 “Optical / electric composite flexible printed circuit board” (issued in September 2006)

  As a method of manufacturing an optical waveguide having an inclined surface, not only can the inclined surface be formed in the core part, but also the manufacturing efficiency is high and a metal layer can be selectively formed on the inclined surface. Yes.

  Non-patent document 1 discloses that an optical waveguide having an inclined surface can be formed. It is disclosed that a metal layer for increasing the light reflection efficiency is formed on the surface of the inclined surface.

  However, as described above, since the optical waveguide is formed on the temporary substrate, after the optical waveguide is formed, it must be peeled off from the temporary substrate and reattached to the substrate on which the optical waveguide was originally formed. There was a problem. And since it is necessary to peel from a temporary substrate, there also existed a problem that the material of a temporary substrate and a 1st cladding layer had to be selected in consideration of the peelability of a temporary substrate and a 1st cladding layer.

  Further, according to Patent Document 1, it is disclosed that an inclined surface that is opposed to the end surface of the core portion at a predetermined angle can be manufactured with high accuracy as the light reflecting surface. It is disclosed that a metal thin film may be deposited on the inclined surface.

  However, the method for depositing the metal thin film has not been particularly studied, and if deposited by a general method, there is a problem that it adheres not only to the inclined surface but also to the end surface of the core portion. It was.

  The present invention has been made in view of such circumstances, and can efficiently manufacture an optical waveguide core having an inclined surface having a predetermined angle, and a metal film is selectively formed on the inclined surface. An object of the present invention is to provide a method for manufacturing an optical waveguide core. Another object of the present invention is to provide an optical waveguide manufacturing method including the optical waveguide core having the inclined surface, an optical waveguide manufactured by the optical waveguide manufacturing method, and an optoelectric composite wiring board including the optical waveguide. .

  An optical waveguide core manufacturing method according to an aspect of the present invention includes: a core part forming step of forming a core part on a surface of a cladding layer formed on a substrate; and the core part substantially with respect to the cladding layer. A vertical vertical plane and the vertical plane facing the vertical plane, and guides light incident from the opposite side of the cladding layer into the core portion or guides light emitted from the core portion to the opposite side of the cladding layer. Forming a recess having an inclined surface for reflecting light, forming a metal layer in the recess, and selectively removing the metal layer formed on the vertical surface. And a metal layer removing step of leaving the metal layer on at least the inclined surface.

  According to such a structure, when manufacturing an optical waveguide core, a core part is formed in the surface of a clad layer, and the recessed part which has an inclined surface in the formed core part is formed. Then, a metal layer is formed in the concave portion formed in the core portion, and the metal layer formed on the vertical surface facing the inclined surface is selectively removed, thereby selectively removing the metal on the inclined surface having a predetermined angle. An optical waveguide core on which a film is formed can be efficiently manufactured.

  In addition, it is difficult to form a metal layer uniformly only on the inclined surface. This is particularly noticeable when the concave portion is small. According to this manufacturing method, even when the concave portion is small, the metal layer on the vertical surface is selectively removed, so that a suitable metal layer can be formed.

  As described above, an optical waveguide core having an inclined surface having a predetermined angle can be efficiently manufactured, and a metal film can be selectively formed on the inclined surface.

  Furthermore, an optical waveguide can be formed by forming a separate cladding layer so as to embed the manufactured optical waveguide core. At that time, since the light incident on the optical waveguide core and the light emitted from the optical waveguide core do not pass through the substrate, any substrate can be used as the substrate. The substrate on which the optical waveguide is to be formed can be used as it is. Therefore, the step of using the temporary substrate and peeling the temporary substrate is not necessary, and the optical waveguide can be efficiently manufactured.

  Further, the metal layer removing step is a step of leaving the metal layer on the inclined surface by removing the metal layer on the vertical surface by the thickness of the metal layer or more on the basis of the outer surface thereof. Is preferred.

  According to such a configuration, the metal layer formed on the vertical surface can be easily removed, and the metal layer can easily remain on the inclined surface. Therefore, a metal film can be easily selectively formed on the inclined surface.

  The core part forming step includes a core material layer forming step of forming a core material layer made of a photosensitive material on the surface of the clad layer formed on the substrate; the core material layer is selectively exposed; and further development is performed. It is preferable to include a core part forming step of forming a core part having a predetermined shape.

  According to such a configuration, the core portion can be easily formed, and thus the optical waveguide core in which the metal film is selectively formed on the inclined surface having a predetermined angle can be more efficiently manufactured.

  Further, the core part forming step includes a core material layer forming step of forming a core material layer made of a photosensitive material on the surface of the cladding layer formed on the substrate, and selectively exposing the core material layer, An exposure step of forming a core portion having a cured portion obtained by curing the photosensitive material and an uncured portion other than the cured portion, wherein the concave portion forming step includes the inclined surface at the cured portion and the vertical surface at the vertical surface. Forming the recess so as to be formed in an uncured portion, and the metal layer removing step removes the metal layer on the vertical surface by developing the core portion where the recess is formed. The step of leaving the metal layer on the inclined surface is preferable.

  According to such a configuration, when the core portion is developed, the metal layer on the vertical surface can be removed, so that the metal layer can easily remain on the inclined surface. Therefore, a metal film can be easily selectively formed on the inclined surface.

  Further, since the selective removal of the metal layer on the vertical surface can be performed by developing the core portion, the optical waveguide core in which the metal film is selectively formed on the inclined surface having a predetermined angle is more efficient. Can be manufactured automatically.

  As described above, an optical waveguide core having an inclined surface forming a predetermined angle can be more efficiently manufactured, and a metal film can be selectively formed on the inclined surface more easily.

  Moreover, it is preferable that the photosensitive material is a material in which the solubility of the portion irradiated with the energy rays in the liquid used in the development is changed. According to such a configuration, only the portion irradiated with the energy beam has low or high solubility in the liquid used in the development, so that desired development can be easily performed. Therefore, it is possible to more efficiently manufacture an optical waveguide core in which a metal film is selectively formed on an inclined surface having a predetermined angle.

  Moreover, it is preferable to provide the roughening process of roughening the surface of the core part in which the said recessed part was formed before the said metal layer formation process. According to such a configuration, the metal layer is easily formed on the concave portion. Therefore, it is possible to more efficiently manufacture an optical waveguide core in which a metal film is selectively formed on an inclined surface having a predetermined angle. Furthermore, the metal layer is difficult to peel from the inclined surface.

  Moreover, it is preferable to provide the coupling process process of processing the surface of the core part in which the said recessed part was formed with a coupling agent before the said metal layer formation process. According to such a configuration, the metal layer is easily formed on the concave portion. Therefore, it is possible to more efficiently manufacture an optical waveguide core in which a metal film is selectively formed on an inclined surface having a predetermined angle. Furthermore, the metal layer is difficult to peel from the inclined surface.

  According to another aspect of the present invention, there is provided a method for manufacturing an optical waveguide, comprising: a core portion forming step of forming a core portion on a surface of a first cladding layer formed on a substrate; A vertical plane substantially perpendicular to one cladding layer, and the vertical plane facing the vertical plane, guiding light incident from the opposite side of the first cladding layer into the core section or emitting light emitted from the core section A recessed portion forming step of forming a recessed portion having an inclined surface for reflecting light so as to be led out to the opposite side of the first cladding layer; a metal layer forming step of forming a metal layer in the recessed portion; and the vertical surface A metal layer removing step of selectively removing the metal layer formed on the metal layer so that at least the metal layer remains on the inclined surface, and forming a second cladding layer so as to embed the core portion And a process. .

  According to such a structure, when manufacturing an optical waveguide core, a core part is formed in the surface of a 1st cladding layer, and the recessed part which has an inclined surface in the formed core part is formed. Then, a metal layer is formed in the concave portion formed in the core portion, and the metal layer formed on the vertical surface facing the inclined surface is selectively removed, thereby selectively removing the metal on the inclined surface having a predetermined angle. An optical waveguide core on which a film is formed can be efficiently manufactured.

  Furthermore, an optical waveguide can be formed by forming the second cladding layer so as to embed the manufactured optical waveguide core. At that time, since the light incident on the optical waveguide core and the light emitted from the optical waveguide core do not pass through the substrate, any substrate can be used as the substrate. The substrate on which the optical waveguide is to be formed can be used as it is. Therefore, the step of using the temporary substrate and peeling the temporary substrate is not necessary, and the optical waveguide can be efficiently manufactured.

  As described above, an optical waveguide having an inclined surface having a predetermined angle can be efficiently manufactured, and a metal film can be selectively formed on the inclined surface.

  An optical waveguide according to another aspect of the present invention is obtained by the method for manufacturing an optical waveguide. According to such a configuration, light incident from the opposite side (second cladding layer side) of the first cladding layer is guided into the core portion or light emitted from the core portion of the first cladding layer. Since an optical waveguide core having an inclined surface capable of reflecting light and having a predetermined angle so as to be led out to the opposite side (second clad layer side) is provided, a light input / output capable of being obtained is obtained. Furthermore, since the metal layer is selectively formed on the inclined surface, a light reflection efficiency high on the inclined surface can be obtained.

  Moreover, the optoelectric composite wiring board according to another aspect of the present invention includes the optical waveguide. According to such a configuration, an optical / electrical composite wiring board including an optical waveguide core having an inclined surface forming the predetermined angle and including an optical waveguide capable of inputting and outputting light is obtained. Therefore, an opto-electric composite wiring board including an optical waveguide and an electric circuit is obtained.

  According to the present invention, there is provided an optical waveguide core manufacturing method capable of efficiently manufacturing an optical waveguide core having an inclined surface having a predetermined angle and selectively forming a metal film on the inclined surface. Can be provided. Also provided are an optical waveguide manufacturing method including the optical waveguide core having the inclined surface, an optical waveguide manufactured by the optical waveguide manufacturing method, and an optoelectric composite wiring board including the optical waveguide.

It is the schematic for demonstrating the manufacturing method of an optical waveguide provided with the optical waveguide core which concerns on 1st Embodiment of this invention. It is the schematic for demonstrating the manufacturing method of an optical waveguide provided with the optical waveguide core which concerns on 2nd Embodiment of this invention. It is the schematic for demonstrating the manufacturing method of the conventional optical waveguide. 6 is a schematic diagram for explaining a method for manufacturing an optical waveguide in Example 1. FIG. 6 is a schematic diagram for explaining a method for manufacturing an optical waveguide in Example 2. FIG. 10 is a schematic diagram for explaining a method of manufacturing an optical waveguide in Example 3. FIG. It is a schematic diagram for demonstrating the shape of the photomask used in each Example.

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

  An optical waveguide core manufacturing method according to an aspect of the present invention includes: a core part forming step of forming a core part on a surface of a cladding layer formed on a substrate; and the core part substantially with respect to the cladding layer. A vertical vertical plane and the vertical plane facing the vertical plane, and guides light incident from the opposite side of the cladding layer into the core portion or guides light emitted from the core portion to the opposite side of the cladding layer. Forming a recess having an inclined surface for reflecting light, forming a metal layer in the recess, and selectively removing the metal layer formed on the vertical surface. And a metal layer removing step of leaving the metal layer on at least the inclined surface.

[First Embodiment]
In the core part forming step, a core material layer forming step of forming a core material layer made of a photosensitive material on the surface of a clad layer formed on a substrate, and selectively exposing the core material layer and further developing the core material layer A core portion forming step of forming a core portion having a predetermined shape, wherein the metal layer removing step removes the metal layer on the vertical surface by a thickness equal to or greater than the thickness of the metal layer on the basis of the outer surface. Thus, an embodiment in the case of a step of leaving the metal layer on the inclined surface will be described.

  FIG. 1 is a schematic diagram for explaining a method of manufacturing an optical waveguide including an optical waveguide core according to the first embodiment of the present invention. FIG. 1A is a schematic cross-sectional view for explaining a core portion forming step in the first embodiment, and FIG. 1B is a schematic cross-sectional view for explaining a recess forming step in the first embodiment. FIG. 1C is a schematic diagram for explaining the metal layer forming step in the first embodiment, and FIG. 1D is a diagram for explaining the metal layer removing step in the first embodiment. FIG. 1E is a schematic cross-sectional view showing the formed optical waveguide.

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

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

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

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

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

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

  As a specific method for forming the first cladding layer 12, for example, a method of bonding a resin film to form the first cladding layer 12, and then curing the resin film, or forming the first cladding layer 12 is performed. For example, a liquid curable resin material or a curable resin material varnish is applied and then cured.

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

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

  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, before irradiating energy rays, it is difficult to dissolve in a liquid used in development described later, but after irradiating energy rays, materials that are easily dissolved or energy rays are irradiated. Before, it is easy to melt | dissolve with respect to the liquid used by the image development mentioned later, but after irradiating an energy ray, the material etc. which become difficult to melt | dissolve are mentioned. Specific examples of the photosensitive material include a photosensitive polymer material. The energy ray is not particularly limited as long as it can change the solubility, but ultraviolet rays are preferably used from the viewpoint of ease of handling. As the photosensitive material, generally, a photosensitive polymer material whose solubility is changed 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.

  As a method for forming the core material layer, a resin film (photosensitive film) made of a photosensitive polymer material having a predetermined refractive index for forming the core material layer on the outer surface of the first cladding layer 12 is used. After applying a varnish of a photosensitive polymer material for forming the core material layer 3, a method of applying a liquid photosensitive polymer material for forming the core material layer, The method of drying etc. are mentioned. In addition, also when forming the said core material layer, in order to activate the outer surface of the said 1st cladding layer 12 and to improve adhesiveness, it is preferable to give a plasma process etc. previously.

  Examples of the resin film (photosensitive film) made of the 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. Examples of the refractive index at the transmission wavelength include about 1.55 to 1.6.

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

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

  As a specific method of forming the core material layer, for example, a method of bonding a resin film to form the core material layer, a liquid curable resin material for forming the core material layer, Alternatively, a method of applying a varnish of a curable resin material is used.

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

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

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

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

The exposure conditions are appropriately selected according to the type of the photosensitive material. For example, as the exposure light, ultraviolet light having a wavelength of about 365 nm is used, and exposure conditions are set to 500 to 3500 mJ / cm ^2. Is selected.

  Further, after the exposure, post-curing with heat is also effective from the viewpoint of ensuring curing. As post-curing conditions, a temperature of about 80 to 160 ° C. and a time of about 20 to 120 minutes are preferable. 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 the development process, when the photosensitive material of the core material layer is a positive type, an unexposed part is washed away with a developer, and an unexposed part is washed away with a developer. This is a step of removing. Examples of the developer include acetone, isopropyl alcohol, toluene, ethylene glycol, or a mixture of these at 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, 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 a predetermined angle with respect to the surface direction of the blade, for example, 45 °. The core portion 13 is cut using the blade 14 which is a surface to form the recess 15. That is, the blade 14 is suspended from the core portion while being rotated so as to be substantially perpendicular to the core portion 13. At this time, the concave portion 15 is opposed to the vertical surface 15a substantially perpendicular to the first cladding layer 12 and the vertical surface 15a, and light incident from the opposite side of the first cladding layer 12 is transmitted to the core portion. 13 so as to form a recess 15 having an inclined surface 15b for reflecting light so that light guided or emitted from the core 13 is led to the opposite side of the first cladding layer 12. Cut the core 13. The inclined surface 15 b is formed in the concave portion 15 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 said blade 14 is a disk-shaped rotary blade, Comprising: The thing with a blade edge | tip in a circumference part, for example, a dicing blade etc., is used. Moreover, the shape of the recessed part 15 will not be specifically limited if it is formed so that the vertical surface 15a and the said inclined surface 15b may oppose, For example, it is groove shape.

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

  Next, as shown in FIG. 1C, a metal layer 16 is formed in the recess 15 formed as described above. It does not specifically limit as a method of forming a metal layer, A well-known method can be used. Specifically, for example, a vapor deposition method such as a vacuum vapor deposition method, a sputtering method, a nano paste method, and the like can be given.

  The thickness of the metal layer 16 is not particularly limited as long as it can reflect light, and examples thereof include a thickness of about 1000 mm.

  It is difficult to uniformly form the metal layer 16 only on the inclined surface 15b. This is particularly noticeable when the recess 15 is small. Therefore, the metal layer 16b on the inclined surface 15b may be formed so that at least the metal layer 16 is formed on the inclined surface 15b, and the metal layer 16a may also be formed on the vertical surface 15a. . By doing so, even if the concave portion 15 is small, the metal layer 16b can be uniformly formed on the inclined surface 15b. And the metal layer 16a on the said vertical surface 15a can be selectively removed by the metal layer removal process mentioned later.

  Further, before the metal layer 16 is formed, the surface of the core portion 13 may be roughened. By doing so, the metal layer 16 is easily formed in the recess 15. The roughening treatment method is not particularly limited. Specifically, for example, a microetching treatment such as a microetching treatment using a permanganic acid treatment solution can be mentioned.

  In addition, before the metal layer 16 is formed, the surface of the core portion 13 may be treated with a coupling agent. By doing so, the metal layer 16 is easily formed in the recess 15. The treatment method with the coupling agent is not particularly limited. Specifically, for example, a method of applying a heat treatment after applying a coupling agent to the surface of the core portion 13 may be used. Moreover, it does not specifically limit as said coupling agent, A well-known coupling agent can be used. Specific examples include a silane coupling agent having an amino group in the molecule.

  Moreover, only one or both of the roughening treatment and the treatment with the coupling agent may be performed. Specifically, after the roughening treatment, the treatment with the coupling agent may be performed. By doing so, the metal layer 16 is easily formed by the recess 15.

  Next, as shown in FIG. 1 (d), the metal layer 16a on the vertical surface 15a is cut using the blade 14 to selectively remove the metal layer 16a. At that time, the blade 14 may be cut so that the 16a is removed, and the core portion 13 may also be cut. That is, the position of the blade 14 is adjusted and cut so that the metal layer 16a formed on the vertical surface 15a is removed by the thickness of the metal layer 16a with reference to the outer surface. By doing so, the metal layer 16b on the inclined surface 15b remains, and the metal layer 16a on the vertical surface 15a is removed. The remaining metal layer 16b guides light incident from the opposite side of the first cladding layer 12 into the core portion 13 or transmits light emitted from the core portion 13 to the opposite side of the first cladding layer 12. As described above, it works as a mirror (micromirror) that reflects light.

  And finally, as shown in FIG.1 (e), by forming the 2nd cladding layer (upper cladding layer) 17 so that the core part 13 formed as mentioned above may be embedded, the optical waveguide 18 is provided. Is formed.

  As a method of forming the second cladding layer 17, 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 light, heat, or the like. A curable resin material varnish for forming the second cladding layer 17 and then curing with light, heat, or the like, or a curable resin for forming the second cladding layer 17. Examples include a method in which a resin film made of a material is bonded and then cured by 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 the guided light than the material of the core portion 13. Usually, a curable resin material of the same kind as the material forming the first cladding layer 12 is used.

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

  Through the steps as described above, the optical waveguide 18 as shown in FIG. In addition, the arrow in FIG.1 (e) shows the optical path of the waveguide light which injects into the optical waveguide 18, and is radiate | emitted.

  The formed optical waveguide 18 is formed by the core portion 13 and a clad layer covering the core portion 13 (the first clad layer 12 and the second clad layer 17). The core portion 13 is formed by a clad layer. Also, the refractive index is high, and light propagating inside is confined in the core by total reflection. Such an optical waveguide 18 is mainly formed as a multimode waveguide. The size of the core portion 13 of the optical waveguide 18 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 Each of 5 to 15 μm and the difference in refractive index between the core portion and the cladding layer are suitably about 0.5 to 3%, but are not limited thereto.

[Second Embodiment]
Next, the core part forming step includes a core material layer forming step of forming a core material layer made of a photosensitive material on the surface of the clad layer formed on the substrate, and selectively exposing the core material layer. An exposure step of forming a core portion having a cured portion obtained by curing the photosensitive material and an uncured portion other than the cured portion, wherein the concave portion forming step includes the inclined surface as the cured portion and the vertical surface as the vertical surface. Forming the recess so as to be formed in the uncured portion, and the metal layer removing step removes the metal layer on the vertical surface by developing the core portion on which the recess is formed. An embodiment in which the metal layer on the inclined surface is left will be described. Portions corresponding to those of the manufacturing method of the optical waveguide having the optical waveguide core according to the first embodiment of the present invention are denoted by the same reference numerals, and detailed description of overlapping portions is omitted.

  FIG. 2 is a schematic view for explaining a method of manufacturing an optical waveguide including an optical waveguide core according to the second embodiment of the present invention. FIG. 2A is a schematic cross-sectional view for explaining a core portion forming step in the second embodiment, and FIG. 2B is a schematic cross-sectional view for explaining a recess forming step in the second embodiment. FIG. 2C is a schematic view for explaining a metal layer forming step in the second embodiment, and FIGS. 2D and 2E are metal layer removal in the second embodiment. It is the schematic for demonstrating a process, FIG.2 (f) is a schematic sectional drawing which shows the formed optical waveguide.

  As a method of manufacturing an optical waveguide according to the second embodiment of the present invention, first, as shown in FIG. 2A, the first cladding of a substrate 11 having a first cladding layer (lower cladding layer) 12 is used. A core portion 13 is formed on the layer 12. At that time, as the core portion 13, a cured portion 13 a and an uncured portion 13 b are formed.

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

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

  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. By doing so, as shown to Fig.2 (a), the core part 13 which has the hardening part 13a and the unhardened part 13b is formed. Specifically, for example, when the photosensitive material of the core material layer is a positive type, the exposed portion becomes the cured portion 13a, and the unexposed portion becomes the uncured portion 13b. Is formed. When the photosensitive material of the core material layer is a negative type, the core portion 13 is formed such that the exposed portion becomes the uncured portion 13b and the unexposed portion becomes the cured portion 13a.

  Further, the exposure can be used without any particular limitation as long as it is a method of exposing light having a wavelength capable of deteriorating (curing, etc.) the photosensitive material with light with a necessary amount of light. Specifically, for example, the same method as in the first embodiment can be used.

  Further, the exposure conditions are appropriately selected according to the type of the photosensitive material. For example, the same conditions as in the first embodiment are selected.

  As in the first embodiment, after-exposure, post-curing with heat is also effective from the viewpoint of ensuring curing. As the post-curing conditions, for example, the same conditions as in the first embodiment are selected.

  Next, as shown in FIG. 2B, one surface of the blade edge is a surface parallel to the surface direction of the blade, and the other surface has a predetermined angle with respect to the surface direction of the blade, for example, 45 °. The core portion 13 is cut using the blade 14 which is a surface to form the recess 15. That is, the blade 14 is suspended from the core portion while being rotated so as to be substantially perpendicular to the core portion 13. At this time, the concave portion 15 is opposed to the vertical surface 15a substantially perpendicular to the first cladding layer 12 and the vertical surface 15a, and light incident from the opposite side of the first cladding layer 12 is transmitted to the core portion. 13 so as to form a recess 15 having an inclined surface 15b for reflecting light so that light guided or emitted from the core 13 is led to the opposite side of the first cladding layer 12. Cut the core 13. Further, the core portion 13 is cut so that the vertical surface 15a is formed in the uncured portion 13b and the inclined surface 15b is formed in the cured portion 13a. The inclined surface 15 b is formed in the concave portion 15 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 shape of the recessed part 15 will not be specifically limited if it is formed so that the vertical surface 15a and the said inclined surface 15b may oppose, For example, it is groove shape.

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

  Next, as shown in FIG. 2C, a metal layer 16 is formed in the recess 15 formed as described above. The method for forming the metal layer is not particularly limited, and for example, the same method as in the first embodiment can be used.

  The thickness of the metal layer 16 is not particularly limited as long as it can reflect light. For example, the thickness may be the same as that of the first embodiment.

  In addition, it is difficult to form the metal layer 16 uniformly only on the inclined surface 15b as in the first embodiment. Therefore, in the present embodiment, similarly to the first embodiment, even if the concave portion 15 is small, the metal layer 16b can be uniformly formed on the inclined surface 15b.

  Further, in order to facilitate the formation of the metal layer 16 in the recess 15, as in the first embodiment, the surface of the core portion 13 may be roughened before the metal layer 16 is formed. And you may process the surface of the said core part 13 with a coupling agent. In addition, the roughening treatment and the treatment with the coupling agent may be performed either in the same manner as in the first embodiment, or both. A roughening treatment method and a treatment method using a coupling agent are not particularly limited. Specifically, for example, the same method as in the first embodiment can be used.

  Next, development processing is performed as shown in FIG. By doing so, the core part 13 as shown in FIG.2 (e) is formed.

  As the development processing, the same method as in the first embodiment can be used. Specifically, for example, as shown in FIG. 2 (d), a method of immersing the entire substrate 11 including the developer 11 is exemplified.

  By performing the development process as described above, the uncured portion 13b is removed, and the metal layer 16a on the uncured portion 13b, that is, the metal layer 16a on the vertical surface 15a is selectively removed. . By doing so, the metal layer 16b on the inclined surface 15b remains, and the metal layer 16a on the vertical surface 15a is removed. The remaining metal layer 16b guides light incident from the opposite side of the first cladding layer 12 into the core portion 13 or transmits light emitted from the core portion 13 to the opposite side of the first cladding layer 12. As described above, it works as a mirror (micromirror) that reflects light.

  Finally, as shown in FIG. 2 (f), as in the first embodiment, the second cladding layer (upper cladding layer) 17 is formed so as to embed the core portion 13 formed as described above. By doing so, the optical waveguide 18 is formed.

  Through the steps as described above, an optical waveguide 18 as shown in FIG. 2 (f) is formed. In addition, the arrow in FIG.2 (f) shows the optical path of the guided light which injects into the optical waveguide 18 and is radiate | emitted.

  The formed optical waveguide 18 is formed by the core portion 13 and a clad layer covering the core portion 13 (the first clad layer 12 and the second clad layer 17). The core portion 13 is formed by a clad layer. Also, the refractive index is high, and light propagating inside is confined in the core by total reflection. Such an optical waveguide 18 is mainly formed as a multimode waveguide. The size of the core portion 13 of the optical waveguide 18 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 Each of 5 to 15 μm and the difference in refractive index between the core portion and the cladding layer are suitably about 0.5 to 3%, but are not limited thereto.

  Moreover, an optical / electrical composite wiring board is obtained by forming the optical waveguide in the first embodiment and the second embodiment on a substrate on which an electric circuit is previously formed. Specifically, for example, the substrate 11 is formed by using a substrate on which an electric circuit is formed in advance.

  Next, as a comparative embodiment for comparison with the above-described embodiment according to the present invention, a step of forming an optical waveguide core, and the optical waveguide core is inclined by processing the optical waveguide core with a rotary blade or the like. A conventional optical waveguide manufacturing method including a step of forming a surface and a step of forming a metal layer on the inclined end in order to improve the reflection efficiency of the inclined surface will be described.

  FIG. 3 is a schematic view for explaining a conventional method of manufacturing an optical waveguide. FIG. 3A is a schematic cross-sectional view for explaining the formation of the core portion on the surface of the first cladding layer formed on the temporary substrate in the conventional method for manufacturing an optical waveguide, and FIG. ) Is a schematic cross-sectional view for explaining the formation of an inclined surface in a conventional method for manufacturing an optical waveguide, and FIG. 3C illustrates the formation of a metal layer in the conventional method for manufacturing an optical waveguide. FIG. 3D is a schematic diagram for explaining the formation of the second cladding layer in the conventional optical waveguide manufacturing method, and FIG. FIG. 3F is a schematic diagram for explaining the peeling of the temporary substrate.

  First, as shown in FIG. 3A, the core portion 33 is formed on the first clad layer 32 of the temporary substrate 31 provided with the first clad layer (lower clad layer) 32. This can be performed in the same manner as in the first embodiment except that the temporary substrate 31 is used instead of the substrate 11.

  Next, as shown in FIG. 3B, the inclined surface 33 a is formed on the core portion 33 by processing the core portion 33 with the rotary blade 34. At this time, the inclined surface 33a guides the light incident from the first cladding layer 33 side into the core part 33 or guides the light emitted from the core part 33 to the first cladding layer 32 side. It is an inclined surface.

  Next, as shown in FIG. 3C, the metal layer 36 is formed on the inclined surface 33a formed as described above.

  Next, as shown in FIG. 3D, as in the first embodiment, a second cladding layer (upper cladding layer) 37 is formed so as to embed the core portion 33 formed as described above.

  Next, as shown in FIG. 3 (e), a substrate 38 is bonded onto the second cladding layer (upper cladding layer) 37.

  Finally, the temporary substrate 31 is peeled off as shown in FIG.

  Through the steps as described above, an optical waveguide 39 as shown in FIG. In addition, the arrow in FIG.3 (f) shows the optical path of the waveguide light which injects into the optical waveguide 39 and is radiate | emitted.

  According to such a manufacturing method, since the guided light passes through the first cladding layer 32, it is necessary to peel off the temporary substrate 31 or to attach the substrate originally intended to form the optical waveguide. . On the other hand, according to the method for manufacturing an optical waveguide core according to the present embodiment, these steps are not necessary, and the manufacturing efficiency is increased.

  From the above, according to the method for manufacturing an optical waveguide core according to the present embodiment, an optical waveguide core having an inclined surface having a predetermined angle can be efficiently manufactured, and a metal is selectively applied to the inclined surface. An optical waveguide core manufacturing method capable of forming a film can be provided.

  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, the manufacturing method of the photocurable resin sheet used by the present Example is demonstrated.

(Manufacture of photocurable resin sheet A for lower clad layer)
7 parts by mass of polypropylene glycol glycidyl ether (“PG207” manufactured by Toto Kasei Co., Ltd.), 25 parts by mass of liquid hydrogenated bisphenol A type epoxy resin (“YX8000” manufactured by Japan Epoxy Resin Co., Ltd.), solid hydrogenated bisphenol A Type epoxy resin (“YL7170” manufactured by Japan Epoxy Resin Co., Ltd.) 20 parts by mass, 1,2-epoxy-4- (2-oxiranyl) cyclohexane adduct of 2,2-bis (hydroxymethyl) -1-butanol ( 8 parts by mass of “EHPE3150” manufactured by Daicel Chemical Industries, Ltd., 2 parts by mass of solid bisphenol A type epoxy resin (“Epicoat 1006FS” manufactured by Japan Epoxy Resin Co., Ltd.), “YP50” manufactured by Toto Kasei Co., Ltd. ) 20 parts by mass, photocationic curing initiator (“SP17” manufactured by Adeka Co., Ltd.) 0 ") 0.5 parts by mass, thermal cationic curing initiator (" SI-150L "manufactured by Sanshin Chemical Industry Co., Ltd.) 0.5 parts by mass, surface conditioner (" F470 "manufactured by DIC Corporation) 1 part by mass of each compounding component was dissolved in 30 parts by mass of toluene and 70 parts by mass of MEK, filtered through a membrane filter having a pore size of 1 μm, and then degassed under reduced pressure to prepare an epoxy resin varnish. This epoxy resin varnish was coated on a 50 μm thick PET film with a bar coater, subjected to primary drying at 80 ° C. for 10 minutes, and then secondary drying at 120 ° C. for 10 minutes. Finally, it was covered with a 35 μm OPP film as a protective film. The lower cladding photocurable resin sheet A thus obtained had a film thickness of 15 μm and a refractive index of 1.54 for light having a wavelength of 579 nm.

(Manufacture of photocurable resin sheet B for core part)
42 parts by mass of liquid bisphenol A type epoxy resin (“Epiclon 850S” manufactured by DIC Corporation), 55 parts by mass of solid bisphenol A type epoxy resin (“Epicoat 1006FS” manufactured by Japan Epoxy Resin Co., Ltd.), phenoxy resin (Tohto Kasei ( Co., Ltd. “YP50”) 3 parts by mass, photocationic curing initiator (Adeca “SP170”) 1 part by mass, and surface conditioner (DIC “F470”) 0.1 part by mass The compounding component was dissolved in a solvent of 24 parts by mass of toluene and 56 parts by mass of MEK, filtered through a membrane filter having a pore diameter of 1 μm, and then degassed under reduced pressure to prepare an epoxy resin varnish. This epoxy resin varnish was formed into a film in the same manner as in “Production of photocurable resin sheet A” described above. The core portion photocurable resin sheet B thus obtained had a film thickness of 40 μm and a refractive index of 1.59 for light having a wavelength of 579 nm. Further, the transmittance at 850 nm was sufficiently high transparency of 0.06 dB / cm.

(Manufacture of photocurable resin sheet C for upper clad layer)
Except changing the application | coating thickness of the epoxy resin varnish, the photocurable resin sheet C for upper clads was obtained by forming into a film like "manufacture of the photocurable resin sheet A". The photocurable resin sheet C thus obtained had a film thickness of 55 μm and a refractive index of 1.54 with respect to light having a wavelength of 579 nm.

Example 1
Example 1 is an example according to the first embodiment. A method of manufacturing an optical waveguide will be described with reference to FIG. FIG. 4 is a schematic diagram for explaining the method of manufacturing the optical waveguide in the first embodiment.

As shown in FIG. 4A, a lower clad layer photocurable resin sheet A is applied to a substrate 11 made of 140 mm × 120 mm UV transparent polycarbonate resin at 60 ° C. and 0.2 MPa using a vacuum laminator “V-130”. Lamination was performed under the conditions of Then, the surface of the photocurable resin sheet A is irradiated with ultraviolet light under a condition of ² J / cm ² with an ultrahigh pressure mercury lamp, and further subjected to heat treatment at 150 ° C. for 30 minutes, so that a first as shown in FIG. One clad layer (lower clad layer) 12 was formed. Then, the surface of the formed lower clad layer 12 was subjected to oxygen plasma treatment.

  Next, as shown in FIG. 4C, the core photocurable resin sheet B is laminated on the surface of the lower clad layer 12 with a vacuum laminator “V-130” at 60 ° C. and 0.2 MPa. As a result, the core material layer 41 was formed.

Then, as shown in FIG. 4D, a photomask 42 having a linear pattern of slits is positioned by superimposing the alignment mark of the photomask 42 and the alignment mark formed on the surface of the core material layer 41. Placed. Then, the ultraviolet light was light-cured at a portion corresponding to the slit of the core material layer 41 with a light amount of ³ J / cm ² with an ultra-high pressure mercury lamp adjusted so that the irradiation light became substantially parallel light. By doing so, as shown in FIG.4 (e), the photocured part (hardened part) 13a and the unhardened part 13b are formed. At that time, as the photomask 42, a photomask 42 having a shape in which a plurality of longitudinal directions of slits of a linear pattern having a predetermined width W and a predetermined length L are arranged in parallel as shown in FIG. . The width W and length L were 40 μm and 120 mm. FIG. 7 is a schematic diagram for explaining the shape of the photomask used in each example, and FIG. 7A is a schematic diagram for explaining the shape of the photomask used in Example 1. . In FIG. 7, an enlarged view of a portion indicated by a circle is also shown.

  Next, heat treatment was performed at 140 ° C. for 2 minutes, and as shown in FIG. 4 (e), a water-based flux cleaning agent adjusted to 55 ° C. as developer 43 (“Pine Alpha ST-” manufactured by Arakawa Chemical Industries, Ltd.) was used. 100SX "), the uncured portion 13b was dissolved and removed by performing a development treatment of immersing in the developer 43. Further, after finishing and washing with water and air blowing, the core portion 13 as shown in FIG. 4F was formed by drying at 100 ° C. for 10 minutes.

  Next, as shown in FIG. 4G, a blade whose one surface is parallel to the surface direction of the blade and whose other surface is a surface whose angle with respect to the surface direction of the blade is 45 °. (Dicing blade) 14 was used, and two positions of 110 mm were cut from both ends of the core at a rotational speed of 15000 rpm. By doing so, the recessed part 15 which has a 45 degree inclined surface 15b was formed. A dicing blade 14 having a particle size of 5000 was used.

  Next, as shown in FIG. 4 (h), only the region where the concave portion 15 is formed is masked with an opened metal mask 44 and vacuum-deposited, thereby forming the concave portion as shown in FIG. 4 (i). A metal layer 16 made of 1000-thick gold was formed on the surface of 15. Thereafter, as shown in FIG. 4 (j), the blade 14 is used and the metal layer 16a formed on the vertical surface 15a is removed by 10 μm on the basis of the outer surface at a rotational speed of 15000 rpm. The position of the blade 14 was adjusted and cut. By doing so, as shown in FIG. 4J, the metal layer 16a was selectively removed, leaving the metal layer 16b on the inclined surface 15b. The remaining metal layer 16b guides light incident from the opposite side of the first cladding layer 12 into the core portion 13 or transmits light emitted from the core portion 13 to the opposite side of the first cladding layer 12. As described above, it works as a mirror (micromirror) that reflects light.

  Next, as shown in FIG. 4 (k), the lower clad layer 12 and the core portion 13 are covered, and the upper clad layer photocurable resin sheet C is heated at 80 ° C. with a vacuum laminator “V-130”. Lamination was performed under the condition of 0.3 MPa.

Then, the second cladding layer (upper cladding layer) 17 was formed by exposing with an ultrahigh pressure mercury lamp at a light amount of ² J / cm ² and further heat treating at 150 ° C. for 30 minutes. By doing so, as shown in FIG. 4L, an optical waveguide 18 composed of the lower cladding layer 12, the core portion 13, and the upper cladding layer 17 was formed. In addition, the arrow in FIG.4 (l) shows the optical path of the waveguide light which injects into the optical waveguide 18, and is radiate | emitted.

  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 LED light source was made incident on the optical waveguide 18 through an optical fiber connected to the input side end. And the emitted light from the optical waveguide 18 was made to enter into a power meter via the optical fiber connected to the output side edge part, and the light quantity P1 of the emitted light was measured.

  On the other hand, in the case where 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 18, the optical fiber connected to the output side end The amount of emitted 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 3.0 dB. The distance between one mirror and the other mirror was 11 cm.

  As described above, according to the present embodiment, when the optical waveguide is formed, the inclined end face for the mirror can be formed at the same time, that is, without using a process different from the process for forming the optical waveguide. It has been found that an optical waveguide having a small inclined surface can be formed.

(Example 2)
Example 2 is an example according to the second embodiment. A method of manufacturing the optical waveguide will be described with reference to FIG. FIG. 5 is a schematic diagram for explaining the method of manufacturing the optical waveguide in the second embodiment.

As shown in FIG. 5 (a), a lower clad layer photocurable resin sheet A is applied to a substrate 11 made of 140 mm × 120 mm UV transparent polycarbonate resin at 60 ° C. and 0.2 MPa using a vacuum laminator “V-130”. Lamination was performed under the following conditions. Then, the surface of the photocurable resin sheet A is irradiated with ultraviolet light under a condition of ² J / cm ² with an ultra-high pressure mercury lamp, and further heat-treated at 150 ° C. for 30 minutes, so that a first as shown in FIG. One clad layer (lower clad layer) 12 was formed. Then, the surface of the formed lower clad layer 12 was subjected to oxygen plasma treatment.

  Next, as shown in FIG. 5C, the core photocurable resin sheet B is laminated on the surface of the lower clad layer 12 with a vacuum laminator “V-130” at 60 ° C. and 0.2 MPa. As a result, the core material layer 41 was formed.

Then, as shown in FIG. 5 (d), the photomask 51 was positioned and placed by overlapping the alignment mark of the photomask 51 and the alignment mark formed on the surface of the core material layer 41. Then, the ultraviolet light was light-cured at a portion corresponding to the slit of the core material layer 41 with a light amount of ³ J / cm ² with an ultra-high pressure mercury lamp adjusted so that the irradiation light became substantially parallel light. By doing so, as shown in FIG.5 (e), the photocured part (hardened part) 13a and the unhardened part 13b are formed. At that time, as the photomask 51, as shown in FIG. 7 (b), a plurality of longitudinal directions of slits of a linear pattern having a predetermined width W1 and a predetermined length L1 are arranged in parallel, from both ends of the slit. The thing of the shape in which the location (width W2) which filled the slit was formed in two places in the predetermined position was used. The width W1, the width W2, and the length L1 were 40 μm, 40 μm, and 120 mm. And the space | interval L2 of the location which has filled the slit was 109.9 mm.

  Next, by performing heat treatment at 140 ° C. for 2 minutes, a core portion 13 having a cured portion 13a and an uncured portion 13b as shown in FIG. 5E was formed.

  Next, as shown in FIG. 5 (f), a blade in which 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 45 °. (Dicing blade) 14 was used, and two positions of 110 mm were cut from both ends of the core at a rotational speed of 15000 rpm. By doing so, as shown in FIG. 5G, a recess 15 having a vertical surface 15a substantially perpendicular to the first cladding layer 12 and a 45 ° inclined surface 15b was formed. A dicing blade 14 having a particle size of 5000 was used. At this time, the core portion 13 is formed such that a vertical surface 15a facing the inclined surface 15b and substantially perpendicular to the first cladding layer 12 is formed in the uncured portion 13b, and the inclined surface 15b is formed in the cured portion 13a. The position of the blade 14 was adjusted so as to cut through.

  Next, as shown in FIG. 5 (h), only the region where the concave portion 15 is formed is masked with an opened metal mask 44 and vacuum-deposited, thereby forming the concave portion as shown in FIG. 5 (i). A metal layer 16 made of 1000-thick gold was formed on the surface of 15.

  Thereafter, as shown in FIG. 5 (j), an aqueous flux cleaning agent adjusted to 55 ° C. (“Pine Alpha ST-100SX” manufactured by Arakawa Chemical Industries, Ltd.) is used as the developer 52, and the developer 52 is immersed in the developer 52. By performing the developing treatment, the uncured portion 13b was dissolved and removed, and the metal layer 16 on the uncured portion 13b, that is, the metal layer 16a on the vertical surface 15a was selectively removed. Then, after finishing and cleaning with water and air blowing, the core part 13 having the metal layer 16b formed on the inclined surface 15b as shown in FIG. 5 (k) is formed by drying at 100 ° C. for 10 minutes. It was. The remaining metal layer 16b guides light incident from the opposite side of the first cladding layer 12 into the core portion 13 or transmits light emitted from the core portion 13 to the opposite side of the first cladding layer 12. As described above, it works as a mirror (micromirror) that reflects light.

  Next, as shown in FIG. 5 (l), the lower clad layer 12 and the core portion 13 are covered, and the upper clad layer photocurable resin sheet C is heated at 80 ° C. with a vacuum laminator “V-130”. Lamination was performed under the condition of 0.3 MPa.

Then, the second cladding layer (upper cladding layer) 17 was formed by exposing with an ultrahigh pressure mercury lamp at a light amount of ² J / cm ² and further heat treating at 150 ° C. for 30 minutes. By doing so, an optical waveguide 18 composed of the lower cladding layer 12, the core portion 13, and the upper cladding layer 17 was formed as shown in FIG. In addition, the arrow in FIG.5 (m) shows the optical path of the waveguide light which injects into the optical waveguide 18, and is radiate | emitted.

  When the above evaluation was performed on the optical waveguide obtained in Example 2, the waveguide loss was 2.8 dB. The distance between one mirror and the other mirror was 11 cm.

  As described above, according to the present embodiment, when the optical waveguide is formed, the inclined end face for the mirror can be formed at the same time, that is, without using a process different from the process for forming the optical waveguide. It has been found that an optical waveguide having a small inclined end face can be formed.

(Example 3)
Example 3 is an example according to the first embodiment, and is an example when the roughening treatment and the treatment with the coupling agent are performed. A method of manufacturing the optical waveguide will be described with reference to FIG. FIG. 6 is a schematic diagram for explaining the method of manufacturing the optical waveguide in the third embodiment.

A substrate 11 made of 140 mm × 120 mm UV transmissive polycarbonate resin as shown in FIG. 6A, a lower clad layer photocurable resin sheet A is applied at 60 ° C. and 0.2 MPa with a vacuum laminator “V-130”. Lamination was performed under the conditions of Then, the surface of the photocurable resin sheet A is irradiated with ultraviolet light under a condition of ² J / cm ² with an ultra-high pressure mercury lamp, and further heat-treated at 150 ° C. for 30 minutes, so that the first as shown in FIG. One clad layer (lower clad layer) 12 was formed. Then, the surface of the formed lower clad layer 12 was subjected to oxygen plasma treatment.

  Next, as shown in FIG. 6C, the core photocurable resin sheet B is laminated on the surface of the lower clad layer 12 with a vacuum laminator “V-130” at 60 ° C. and 0.2 MPa. As a result, the core material layer 41 was formed.

Then, as shown in FIG. 6D, the photomask 42 having the linear pattern slit is positioned by overlapping the alignment mark of the photomask 42 and the alignment mark formed on the surface of the core material layer 41. Placed. Then, the ultraviolet light was light-cured at a portion corresponding to the slit of the core material layer 41 with a light amount of ³ J / cm ² with an ultra-high pressure mercury lamp adjusted so that the irradiation light became substantially parallel light. By doing so, as shown in FIG.6 (e), the photocured part (hardened part) 13a and the unhardened part 13b are formed. At that time, as the photomask 42, a photomask 42 having a shape in which a plurality of longitudinal directions of slits of a linear pattern having a predetermined width W and a predetermined length L are arranged in parallel as shown in FIG. . The width W and length L were 40 μm and 120 mm. FIG. 7 is a schematic diagram for explaining the shape of the photomask used in each example, and FIG. 7A is a schematic diagram for explaining the shape of the photomask used in Example 1. . In FIG. 7, an enlarged view of a portion indicated by a circle is also shown.

  Next, heat treatment was performed at 140 ° C. for 2 minutes, and as shown in FIG. 6E, a water-based flux cleaning agent adjusted to 55 ° C. as a developer 43 (“Pine Alpha ST-” manufactured by Arakawa Chemical Industries, Ltd.) was used. 100SX "), the uncured portion 13b was dissolved and removed by performing a development treatment of immersing in the developer 43. Then, after finishing and washing with water and air blowing, the core portion 13 as shown in FIG. 6F was formed by drying at 100 ° C. for 10 minutes.

  Next, as shown in FIG. 6 (g), a blade in which one surface of the blade edge is a surface parallel to the surface direction of the blade and the other surface is a surface having an angle of 45 ° with respect to the surface direction of the blade. (Dicing blade) 14 was used, and two positions of 110 mm were cut from both ends of the core at a rotational speed of 15000 rpm. By doing so, the recessed part 15 which has a 45 degree inclined surface 15b was formed. A dicing blade 14 having a particle size of 5000 was used.

  Next, the substrate 11 including the core portion 13 in which the concave portion 15 was formed was subjected to a microetching process using a permanganic acid processing solution. Specifically, it was first immersed for 3 minutes in a swelling liquid adjusted to 65 ° C. (Swelling Dip Securigant P 400 ml / L, sodium hydroxide 10 g / L manufactured by Atotech Japan). By doing so, the core part 13 swelled. Then, it was immersed for 10 minutes in the permanganic acid processing liquid (Atotech Japan Concentrate Compact CP 700ml / L, sodium hydroxide 45g / L) adjusted to 75 degreeC. By doing so, the surface of the core part 13 was subjected to a microetching process using a permanganic acid treatment liquid. Then, it was immersed for 5 minutes in the neutralization liquid (Atotech Japan reduction solution securigant P500 70ml / L, 98% sulfuric acid 50ml / L) adjusted to 40 degreeC. By doing so, the liquid used for the said process was neutralized.

  Next, as shown in FIG. 6 (h), a coupling agent (KBM603 manufactured by Shin-Etsu Silicone Co., Ltd.) in a 1% by mass ethanol solution was added to the core part 13 subjected to the micro-etching process at 1000 rpm / 30 seconds. The coating was performed under the following conditions. Thereafter, heat treatment was performed at 160 ° C. for 1 hour.

  Next, as shown in FIG. 6 (i), only the region where the recess 15 is formed is masked with the opened metal mask 44, and vacuum deposition is performed, so that the recess is formed as shown in FIG. 6 (j). A metal layer 16 made of 1000-thick gold was formed on the surface of 15. Thereafter, as shown in FIG. 6 (k), the blade 14 is used and the metal layer 16a formed on the vertical surface 15a is removed by 10 μm on the basis of the outer surface at a rotational speed of 15000 rpm. The position of the blade 14 was adjusted and cut. By doing so, as shown in FIG. 6 (k), the metal layer 16a was selectively removed, leaving the metal layer 16b on the inclined surface 15b. The remaining metal layer 16b guides light incident from the opposite side of the first cladding layer 12 into the core portion 13 or transmits light emitted from the core portion 13 to the opposite side of the first cladding layer 12. As described above, it works as a mirror (micromirror) that reflects light.

  Next, as shown in FIG. 6 (l), the lower clad layer 12 and the core portion 13 are covered, and the photocurable resin sheet C for the upper clad layer is heated at 80 ° C. with a vacuum laminator “V-130”. Lamination was performed under the condition of 0.3 MPa.

Then, the second cladding layer (upper cladding layer) 17 was formed by exposing with an ultrahigh pressure mercury lamp at a light amount of ² J / cm ² and further heat treating at 150 ° C. for 30 minutes. By doing so, an optical waveguide 18 composed of the lower cladding layer 12, the core portion 13, and the upper cladding layer 17 was formed as shown in FIG. In addition, the arrow in FIG.6 (m) shows the optical path of the waveguide light which injects into the optical waveguide 18, and is radiate | emitted.

  When the above evaluation was performed on the optical waveguide obtained in Example 3, the waveguide loss was 3.0 dB. The distance between one mirror and the other mirror was 11 cm.

  As described above, according to the present embodiment, when the optical waveguide is formed, the inclined end face for the mirror can be formed at the same time, that is, without using a process different from the process for forming the optical waveguide. It has been found that an optical waveguide having a small inclined end face can be formed.

11 Substrate 12 First cladding layer (lower cladding layer)
13 Core part 13a Cured part 13b Uncured part 14 Blade (dicing blade)
15 Recess 15a Vertical surface 15b Inclined surface 16 Metal layer 17 Second clad layer (upper clad layer)
18 Optical waveguide 21, 43, 52 Developer 41 Core material layer 42, 51 Photomask 44 Metal mask

Claims (7)

A core part forming step of forming a core part on the surface of the clad layer formed on the substrate;
Light that is incident on the core portion from the opposite side of the cladding layer is guided to or emitted from the core portion. A recess forming step of forming a recess having an inclined surface for reflecting light so as to guide light to the opposite side of the cladding layer;
A metal layer forming step of forming a metal layer in the recess;
Wherein by selectively removing the metal layer formed on a vertical surface, and at least a metal layer removing step to leave a metal layer on the inclined surface,
The core part forming step includes a core material layer forming step of forming a core material layer made of a photosensitive material on a surface of a clad layer formed on the substrate, and selectively exposing the core material layer, An exposure step for forming a core portion having a cured portion obtained by curing the photosensitive material and an uncured portion other than the cured portion;
The recess forming step is a step of forming the recess so that the inclined surface is formed in the cured portion and the vertical surface is formed in the uncured portion;
The metal layer removing step is a step of developing the core portion in which the concave portion is formed to remove the metal layer on the vertical surface and leave the metal layer on the inclined surface. Manufacturing method of optical waveguide core. The method of manufacturing an optical waveguide core according to claim 1 , wherein the photosensitive material is a material whose solubility in a liquid used in the development of a portion irradiated with energy rays is changed. The manufacturing method of the optical waveguide core of Claim 1 or Claim 2 provided with the roughening process of roughening the surface of the core part in which the said recessed part was formed before the said metal layer formation process. The manufacturing of the optical waveguide core according to any one of claims 1 to 3, further comprising a coupling treatment step of treating a surface of the core portion on which the concave portion is formed with a coupling agent before the metal layer forming step. Method. A core part forming step of forming a core part on the surface of the first cladding layer formed on the substrate;
A vertical plane that is substantially perpendicular to the first cladding layer and the vertical plane that is opposed to the vertical plane and guides light incident from the opposite side of the first cladding layer into the core section or the core section. A recess forming step of forming a recess having an inclined surface for reflecting the light so as to lead out the light emitted from the first clad layer to the opposite side;
A metal layer forming step of forming a metal layer in the recess;
A metal layer removing step of selectively removing the metal layer formed on the vertical surface to leave at least the metal layer on the inclined surface;
A cladding layer forming step of forming a second cladding layer so as to embed the core portion ,
The core part forming step includes forming a core material layer made of a photosensitive material on the surface of the first cladding layer formed on the substrate, and selectively exposing the core material layer. And an exposure step for forming a core portion having a cured portion obtained by curing the photosensitive material and an uncured portion other than the cured portion,
The recess forming step is a step of forming the recess so that the inclined surface is formed in the cured portion and the vertical surface is formed in the uncured portion;
The metal layer removing step is a step of developing the core portion in which the concave portion is formed to remove the metal layer on the vertical surface and leave the metal layer on the inclined surface. Manufacturing method of optical waveguide. An optical waveguide obtained by the method for manufacturing an optical waveguide according to claim 5 . A photoelectric composite wiring board comprising the optical waveguide according to claim 6 .

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