JP2006184802A - Optical waveguide and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical waveguide and its manufacturing method which does not require new part for the connection between wiring plates, thus the number of connections is reduced and production cost and connection loss are also reduced. <P>SOLUTION: The optical waveguide includes a clad layer and a core layer 1 and signal light beams are made incident, propagated and emitted via the core layer 1. In the optical waveguide, a plurality of waveguide layers formed on the clad layer and the core layer 1 are included, and a plurality of waveguide layers are laminated in at least a portion of the waveguide. The manufacturing method is for the optical waveguide, in which the clad layer is made of a bottom clad layer and a top clad layer. After the bottom clad layer is coated, a mold, on which a recessed and projected pattern is formed, is pressed onto the coated bottom clad layer, a groove section is formed onto the bottom clad layer, by transferring the recessed and projected pattern onto the surface of the bottom clad layer, and the core layer 1 is coated in the groove section. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical waveguide and a method for manufacturing the same. More specifically, the present invention is used with a wiring board, in particular, an electric / optical mixed wiring board configured by using both electric wiring and optical wiring together with an electric wiring portion. The present invention relates to an optical waveguide and a method for manufacturing the same.

  2. Description of the Related Art In recent years, an optical wiring technique has been introduced in an electric wiring board in an electronic device for the purpose of improving a signal transmission speed. Specifically, an optical waveguide is applied as an optical wiring in the wiring board, and is used by being laminated with an electric wiring layer. Such a wiring board configured by mixing electrical wiring and optical wiring is generally called an electrical / optical mixed wiring board.

Various studies have so far been made on such an electric / optical mixed wiring board. For example, Patent Document 1 discloses that high-density mounting or miniaturization is possible, and that mounting of optical components is mounting of electrical components. For the purpose of realizing an optical / electrical wiring board that can be performed by the same method, an optical / electrical wiring board in which an electric wiring board in which electric wiring is embedded and an optical substrate in which an optical waveguide is embedded is laminated, A technique for penetrating through a columnar conductive guide formed on an electric wiring board is described. Further, Patent Documents 2, 3 and the like also disclose improved techniques related to the electric / optical mixed wiring board.
JP 2000-340906 A (Claims etc.) JP 2003-287737 A (Claims etc.) JP 2004-163722 A (Claims etc.)

  Conventionally, optical waveguides used in the above-mentioned mixed electrical / optical wiring board have been commercialized by designing a core pattern such as a straight line or a Y-shaped branch in advance. Therefore, when using the actual wiring board for mounting light-emitting elements, light-receiving elements, etc., the mounting position, mounting direction, number of mounted elements, etc. vary widely. Therefore, there is a problem in that it is disadvantageous in terms of lead time to commercialization and cost.

  Accordingly, an object of the present invention is to solve the above problems, eliminate the need for design and manufacture according to individual cases at the time of mounting, shorten the lead time to commercialization, and reduce the cost. An object of the present invention is to provide an optical waveguide that can be manufactured and a method for manufacturing the same.

  As a result of intensive studies, the present inventors have found that by forming an optical waveguide with a plurality of waveguide layers, it is possible to set the waveguide core arrangement region as desired, thereby eliminating the above problem. As a result, the present invention has been completed.

  That is, the optical waveguide of the present invention includes a clad layer and a core layer, and an optical waveguide for inputting, propagating, and emitting signal light through the core layer includes a waveguide layer composed of the clad layer and the core layer. A plurality of waveguide layers are included, and the plurality of waveguide layers are laminated at least partially.

  The optical waveguide manufacturing method of the present invention is the above-described optical waveguide manufacturing method in which the cladding layer is composed of a lower cladding layer and an upper cladding layer, and the coating is performed after the lower cladding layer is applied. A mold having a concavo-convex pattern formed on the lower clad layer is pressed, and the concavo-convex pattern is transferred to the surface of the lower clad layer to form a groove in the lower clad layer, and the core layer is applied in the groove. It is characterized by working.

  Furthermore, another optical waveguide manufacturing method of the present invention is the above-described optical waveguide manufacturing method of the present invention, a mask step of covering a single layer film containing a photobleaching material with a mask member from one or two directions, A light irradiation step of irradiating the single layer film with light from one or two directions through the mask member; and a peeling step of peeling the mask member from the single layer film. It is.

  According to the present invention, by adopting the above-described configuration, it is possible to set the waveguide core arrangement region as desired, so that any portion where the in-plane waveguide core is formed of a plurality of layers can be used from anywhere. Since it becomes possible to take out optical signals, it becomes unnecessary to design and manufacture on a case-by-case basis according to the purpose of use, etc., thereby enabling standardization and commonization of mounting optical waveguides, It has become possible to significantly reduce lead time and reduce costs.

Hereinafter, preferred embodiments of the present invention will be described in detail.
The optical waveguide of the present invention includes a clad layer and a core layer, and emits, propagates, and emits signal light through the core layer, and includes a plurality of waveguide layers composed of the clad layer and the core layer, In addition, the present invention is characterized in that the plurality of waveguide layers are laminated at least partially.

  FIG. 1A is a schematic perspective view showing only the core layers 1A and 1B of the optical waveguide of the present invention. In the present invention, by providing a plurality of waveguide layers, as shown in the figure, the degree of freedom of the arrangement region of the core layer 1 that becomes a path for propagating light is greatly expanded, so that a desired core layer shape is formed. By doing so, it is possible to appropriately extract light as desired from any location where the core layer 1 exists without designing according to the purpose of use.

  In the present invention, as long as a plurality of waveguide layers are laminated at least in part, the overall waveguide shape, laminated shape, material, and the like are not particularly limited. For example, as shown in the figure, the core layer can be provided between two of the laminated waveguide layers so that the core layers 1A and 1B are orthogonal to each other. A plurality of core layers 1A and 1B extending in substantially parallel to each other in two directions orthogonal to each other are formed on at least a part of two of the waveguide layers, that is, the optical waveguide layer is disposed on the upper surface. When viewed from above, the plurality of core layers are preferably arranged so as to form a lattice shape as a whole.

  The optical waveguide of the present invention can be used as an optical wiring in a wiring board, and is particularly preferably used by being disposed together with an electric wiring portion in an electric / light mixed wiring board. FIG. 2 shows a configuration example of an electric / light mixed wiring board as an example of a wiring board using the optical waveguide of the present invention. The electric / optical mixed wiring board shown in the figure includes an optical waveguide 10 of the present invention including a core layer 1 and a clad layer 2 (lower clad layer), and an electric wiring layer 40 including an electric wiring portion (not shown). The optical waveguide 10 is laminated and transmits an optical signal between the light emitting element 31 and the light receiving element 32, for example. Note that reference numeral 3 in the drawing represents an upper clad layer, and for simplicity of explanation, only one waveguide layer is shown. The wiring board according to the present invention is not particularly limited in its specific configuration as long as optical wiring using an optical waveguide can be applied.

  The plurality of waveguide layers according to the present invention may be directly laminated, or may be laminated via the electric wiring layer 40, and is not particularly limited, but is laminated via the electric wiring layer 40. In this case, it is necessary to secure an optical path by opening a hole in the electrical wiring layer 40 for a portion that transmits and receives light between the waveguide layers. The same applies to the case where an optical signal is exchanged between the core layers 1 via the cladding layer. On the other hand, when a pair of core layers 1 are opposed to each other without a cladding layer, the core layer 1 has little absorption in the wavelength region of light for transmitting signals, and preferably has an absorption loss of 0.2 dB / By providing the adhesive layer 6 (see FIG. 1C) made of a resin of cm or less, when light is propagated to the core layer in one waveguide layer, the core layer in the other waveguide layer Light leakage can be prevented. As such a resin, for example, those listed later as photo-curing materials used in the photoimprint method can be appropriately selected and used. In addition, adhesion between a plurality of waveguide layers can be usually performed using an optical adhesive composed of a mixture of an oligomer such as epoxy acrylate, urethane acrylate, and polyester acrylate and an acrylate monomer, or a thermosetting resin. Alternatively, a photocurable resin may be used. Such a thermosetting resin may be any material that absorbs little light in the wavelength region of signal light. For example, polyimide, epoxy, acrylic, or the like can be used, and is not particularly limited. Further, the photo-curable resin may be any material that absorbs less light in the wavelength region of signal light. For example, a material used in an imprint method to be described later can be used, and is not particularly limited. In particular, it is preferable to perform adhesion using the same material as that of the cladding layer. For example, one of the waveguide portions can be manufactured without the upper cladding layer, and can be bonded upside down.

  As illustrated, in the optical waveguide 10 of the present invention, the traveling direction of light can be changed using, for example, a mirror 50 or a slit structure equivalent thereto. The mirror 50 can be provided at a certain angle with respect to the traveling direction of light, for example, in a direction of 45 °. For example, as shown in the drawing, the mirror 50 forms 45 ° with respect to the traveling direction of light and is relative to the core layer surface. Even if two mirrors 50 provided in the direction of 45 ° are combined, it is possible to change the optical path from the lower core layer 1 to the upper core layer 1 or to extract light from that portion. Become. The mirror 50 can be manufactured by a dicing method using a blade, an optical pin method, a laser method, or the like, or may be coated with gold or the like.

  Therefore, the setting of the optical path in the optical waveguide 10 according to the present invention can be easily performed by providing the mirror 50 or the like at an appropriate position of the core layer 2 that requires an optical path change or optical coupling with another optical waveguide layer. Is possible.

  As a method for producing an optical waveguide according to the present invention, a method in which a plurality of waveguide layers are separately produced and bonded together with the adhesive layer 6, an optical adhesive, a photocurable resin, or the like can be used. . As a method for manufacturing individual waveguide layers, for example, after forming the lower cladding layer 2, the core layer material is applied and the core layer 1 is formed by mask exposure, and the upper cladding layer is further formed on the upper surface and side surfaces thereof. (Not shown) Direct exposure method for forming and coating the core layer material after the formation of the lower cladding layer 2, and the core layer by direct drawing by irradiation of radiation such as electron beam, ultraviolet ray, laser beam, etc. A known method such as a method for forming 1 and a method using multilayer extrusion can be appropriately used, and is not particularly limited, but a method using a so-called imprint method (also referred to as a hot embossing method or a nanoimprint method). Is preferred.

  FIG. 3 shows an example of a manufacturing process of a waveguide layer according to the present invention using such an imprint method. In the example shown in the figure, (a) after coating the lower clad layer 2 on the substrate 5, (b) pressing the mold 70 on which the concave / convex pattern is formed on the lower clad layer 2, The groove 4 is formed by transferring to the surface of the cladding layer 2 (imprint process). Thereafter, (c) the core layer 1 is applied in the groove 4, and (d) the upper cladding layer 3 is laminated as desired, whereby a waveguide layer can be manufactured.

  As described above, by forming the groove portion 4 using the imprint method, the development work necessary for the conventional lithography method becomes unnecessary, and it becomes possible to efficiently manufacture in a simple process. Further, since the beam system is unnecessary, the cost of the apparatus can be suppressed, and it is possible to contribute to cost reduction in that an expensive resist material such as a chemical amplification system is unnecessary. Furthermore, since the imprint method can transfer the pattern shape as it is, it can easily obtain the three-dimensional shape as designed, and various cross-sectional shapes such as curved surfaces that cannot be handled by the conventional lithography method. In addition, there is an advantage that an optical waveguide can be formed. In the illustrated example, a mold (template) 70 having a convex portion having a rectangular cross section is used. However, for example, when a core layer having a substantially circular cross section is formed, the cross section of the convex portion is semicircular. A mold that is U-shaped, V-shaped, or the like may be used, and is not particularly limited.

  Here, in the imprint process, as the material of the lower clad layer 2, either a thermal imprint method using a thermoplastic material or a thermosetting material or a photoimprint method using a photocuring material is preferable. Can be adopted. Among these, in the case of using a thermoplastic material, after pressing the mold 70 at a temperature equal to or higher than its glass transition point, the lower clad layer 2 is cooled and cured before releasing from the mold 70, thereby forming the shape. The lower cladding layer 2 in which the pattern of the groove 4 is formed with high accuracy can be formed. Further, when a thermosetting material is used, the lower clad layer 2 is thermally cured after pressing and before releasing from the mold 70, and when a photocuring material is used, similarly, after pressing, the mold Before releasing from 70, the lower clad layer 2 may be photocured. In any case, since the lower clad layer 2 can be cured before releasing from the mold 70, the pattern of the groove 4 having a desired shape, that is, the pattern of the core layer 1 is formed without causing distortion. be able to.

  The material of the lower clad layer 2 that can be used in the thermal imprint method is not particularly limited as long as it is a thermoplastic material and a thermosetting material excellent in transparency. For example, examples of the thermoplastic material include polymethyl methacrylate (PMMA), polycarbonate (PC), polystyrene (PS), polyethylene (PE), and polypropylene (PP). These materials may be used alone or blended. In the case of blending, each material to be blended has a structure in which a three-dimensional network structure of each material is interpenetrated (IPN (Inter penetrating networks) structure). Good. A component of the above material may be used as a block to form a copolymer. It is also possible to improve transferability by adding an appropriate amount of solvent to the above material.

  Thermosetting materials include silicon materials, polydimethylsiloxane (PDMS), acrylic resins, polyimide resins, epoxy resins, polyester resins, polyarylate resins, fluorine resins, and deuterated products of these resins. Etc. These materials may be used singly or as a blend, and in the case of blending, the materials to be blended may take a structure (IPN structure) in which the three-dimensional network structure of each material is interpenetrated. A component of the above material may be used as a block to form a copolymer.

  Next, the photoimprint method has an advantage that the process time can be shortened compared with the thermal imprint method because the curing speed of the material is generally high. Photocuring materials that can be used in such a photoimprint method include (a) a dichromate-based photosensitive resin, (b) a photodecomposable photosensitive resin, (c) a photodimerized photosensitive resin, (d) It is classified as a photopolymerization type photosensitive resin.

  (A) Bichromate-based photosensitive resins include natural polymers such as gelatin, glue, egg white, gum arabic, and ceramics, or synthetic polymers such as PVA (polyvinyl alcohol) and polyacrylamide, and heavy chromium. Examples include ammonium acid or potassium dichromate. In addition, (b) photodegradable photosensitive resins include aromatic diazonium salt resins, o-quinonediazide resins, and azide compound-containing resins. (C) Photodimerized photosensitive resins include cinnamic acid ester resins. Resin. Any of these can be used as the lower cladding layer material in the optical imprint method.

Furthermore, (d) as a photopolymerizable photosensitive resin, a photoradical polymerization composition using a radical polymerization reaction of an unsaturated double bond, a photoaddition reaction system using an addition reaction of a thiol group to a double bond Examples thereof include a composition and a photocationic polymerization composition utilizing a ring-opening addition reaction (cationic polymerization) of an epoxy group. Among these, as radical photopolymerization compositions, unsaturated polyesters, unsaturated polyurethanes, unsaturated epoxy resins, oligoester (meth) acrylates, poly (meth) acryloyl groups, maleic acid, fumaric acid groups introduced as functional groups are used. Examples include ether (meth) acrylate. In addition, as a photoaddition reaction system composition utilizing the addition reaction of a thiol group to a double bond, pentaerythritol tetrakis (β-mercaptopropio A compound having a thiol group such as nate), and the photocationic polymerization composition is a photocationic polymerization initiator that releases a Lewis acid such as BF ₃ , SnCl ₄ , or PF ₅ by light irradiation. Used for photo ring-opening polymerization of an epoxy group or the like. Any of the above photopolymerizable photosensitive resins can be used in the photoimprinting method.

  In the imprint method, as described above, a dimensional change occurs due to thermal shrinkage or photocuring shrinkage. Therefore, it is necessary to design the optical waveguide by predicting the amount of change in advance according to the material to be used. Also, it should be noted that the resolution is determined by the mold and that a resin residual film may be generated in the mold.

  When the imprint method is used, the formation of the lower cladding layer 2 and the upper cladding layer 3 shown in FIGS. 3A and 3D may be performed by a conventional coating method depending on the material to be used. Is not to be done. For example, a spin coating method, a comma method, a gravure method, or the like can be used. Moreover, you may laminate | stack the film-form clad layer produced separately as needed. In addition, the formation of the core layer 1 in the groove 4 shown in FIG. 3C is not particularly limited. For example, spin coating, screen printing, offset printing, gravure printing, inkjet, dispenser application, applicator It can be carried out by using a conventional method capable of supplying a liquid or at least fluid material such as coating, and it is particularly preferable to use an ink jet or dispenser coating, particularly a dispenser coating method. It is. After the application of the upper cladding layer 3 shown in FIG. 3 (d), heat or light (ultraviolet (UV), electron beam (EB), etc.) is appropriately applied to cure the uncured portion. A waveguide layer can be obtained. In addition, it is preferable to give heat or light after the coating of the core layer 1 shown in FIG. 3C in order to cure the core layer to some extent and maintain the shape.

  In the present invention, a method in which the core layer is formed by a photobleaching method using a photobleaching material whose refractive index changes by light irradiation can also be suitably used. Specifically, for example, the core layer using the photobleaching material can be formed as follows.

  FIG. 4 is a schematic explanatory view showing an example of a manufacturing process of a waveguide layer using a photo bleach method. The manufacturing method shown in the figure includes mask steps (a) to (c) in which a single layer film 111 containing a photobleaching material is sandwiched between a pair of mask members 112A and 112B, and a pair of mask members 112A with respect to the single layer film 111. , 112B, a first light irradiation step (d) for irradiating light from two opposite directions, a peeling step (e) for peeling the pair of mask members 112A, 112B from the single layer film 111, and a pair of masks A second light irradiation step (f) in which the single-layer film 111 from which the members 112A and 112B have been peeled is irradiated again with light from the two directions, as shown in FIG. A waveguide layer including the clad layer 102 and the core layer 101 can be obtained by a simple method.

  In the illustrated mask steps (a) to (c), the mask member 112B is used as a substrate (a), and a single layer film material containing a photobleaching material is applied onto the mask member 112B to form the single layer film 111. (B), and then a mask member 112A is further laminated on the formed single layer film 111, whereby the single layer film 111 is sandwiched between the pair of mask members 112A and 112B. Here, the illustrated pair of mask members 112A and 112B is a patterning mask in which a shape corresponding to the core layer 101 is patterned, and portions indicated by reference numerals 113A and 113B correspond to the core layer 101. Therefore, when the single layer film 111 is sandwiched between the mask members 112A and 112B, care must be taken that the patterning shapes 113A and 113B of the mask members 112A and 112B on both sides match each other.

  In this case, it is not always necessary to fix the mask members 112A and 112B to the single layer film 111, and the positional relationship between the single layer film 111 and the mask members 112A and 112B is not displaced during light irradiation. As long as both are in close contact with each other, a gap may be provided. In addition, when the mask member and the single layer film are brought into close contact as in the case where the mask member is used as a substrate, the mask member is separated from the surface of the one or both mask members facing the single layer film 111 prior to the mask process. It is preferable to perform a mold treatment, which facilitates peeling of the mask member in the subsequent peeling step (e). The method for forming the monolayer film 111 on the substrate or the mask member is not particularly limited, and a conventional coating means such as a spin coating method, a comma bar coating method, or a micro gravure method is appropriately used. Then, after applying the single layer film material, a method of drying and curing by heat may be used.

  Next, in the first light irradiation step (d), the single layer film 111 is irradiated with light through the mask members 112A and 112B, so that the width of the illustrated single layer film 111 corresponds to the patterning shape. A refractive index distribution is formed in the direction. As shown in the drawing, at this time, the light transmitted through the mask members 112A and 112B wraps inward from the patterning width corresponding to the core layer 101 due to the diffraction phenomenon, and therefore approaches both ends in the width direction in the single layer film 111. As the irradiation intensity of light is higher and therefore the refractive index is lower, the irradiation intensity is lower and the refractive index change is smaller as it is closer to the center, so that the vicinity of the center has a higher refractive index than the vicinity of both ends. As a result, the clad layer 102 can be formed at both ends in the width direction of the single layer film 111, and a continuous refractive index gradient can be formed in the vicinity of the center in the width direction.

  Next, after peeling the pair of mask members 112A and 112B from the single layer film 111 in the peeling step (e), the single layer film 111 is again irradiated with light from the two directions in the second light irradiation step (f). Thus, a refractive index distribution can be formed in the height direction in the single layer film 111. In this case, as shown in the figure, by irradiating light from the vertical direction, the irradiation intensity is higher as it is closer to the upper and lower surfaces, and the irradiation intensity is lower as it is closer to the center in the height direction. Similarly, a clad portion can be formed in the vicinity of the surface in the vertical direction, and a refractive index gradient can be formed in the vicinity of the center portion. As a result, as shown in the figure, the cross section is substantially circular and refracts toward the center. This is because a waveguide layer composed of the core layer 101 having a continuously high rate and the clad layer 102 formed around the core layer 101 can be manufactured. Note that the light irradiation intensity in the first light irradiation step (d) and the second light irradiation step (f) may be appropriately set depending on the thickness and material of the single layer film 111, the size of the target core portion, and the like. Well, not particularly limited.

  As described above, the single-layer film 111 needs to include a photobleaching material, that is, a material whose refractive index changes by light irradiation, thereby changing the refractive index in the single-layer film 111. Thus, the core layer 101 and the clad layer 102 can be formed. Such a photobleaching material is not particularly limited, and can be appropriately selected and used from those conventionally used. For example, polysilane and the like can be representatively exemplified. In particular, in order to obtain a sufficient difference in refractive index between the core layer 101 and the clad layer 102, it is preferable to use a photobleaching material having a refractive index change amount by light irradiation of 0.001 or more. Furthermore, the thickness of the single-layer film 111 may be as long as it can form a structure including the core layer 102 and the clad layer 102 as shown in the figure, and is preferably 10 μm or more in thickness.

  The single-layer film material for forming the single-layer film 111 may be formed only by the photobleaching material, but may be formed by appropriately combining the photobleaching material and other materials, particularly It is not limited. Other materials that can be used in combination with the photobleaching material can be appropriately selected from those usually used as the core or cladding material in this field.

  Specific examples of such other materials include polymethyl methacrylate (PMMA) having excellent transparency, acrylic resin, epoxy resin, polysilane resin, polyimide resin material, and deuterium. Or fluorinated compounds. Since these resin materials have low absorption with respect to light in the wavelength region of 1.3 μm or more and 1.55 μm or less, a low-loss optical device can be formed by using these materials. .

  Further, depending on the shape of the target core part, as shown in FIG. 5, (A) a single layer film 211 containing a photobleaching material formed on the lower cladding layer 214A is (B) a mask member from one direction. 212, and (C) the single-layer film 211 is irradiated with light through the mask member 212, and then (D) the mask member 212 is peeled from the single-layer film, and (E) By providing the clad layer 214B, a method of obtaining the optical waveguide 200 including the clad layer 201 and the core layer 202 can also be used. Also in this case, each manufacturing process can be performed in the same manner as described above, and is not particularly limited.

  As materials for the upper and lower cladding layers and the core layer, in addition to those described above, a conventional inorganic material or organic material can be appropriately selected and used. However, the core layer has a higher refractive index than the upper and lower cladding layers. It is necessary to make a selection in relation to the material of each other layer. Specifically, for example, various requirements such as photocuring materials, thermosetting materials, thermoplastic materials (including solutions), oligomers (including solutions), and polymer solutions, such as transparency and heat resistance. From the viewpoint of characteristics and the like, it can be appropriately selected and used.

（式中、Ｒ¹は水素原子またはメチル基を表し、Ｒ²は炭素数８〜２０のアルキル基を表す）で表される化合物、ジ（メタ）アクリルエステル、トリ（メタ）アクリルエステル、さらには、スチレン、ジビニルベンゼン等のスチレン系モノマーなどを挙げることができる。 Among the above monomers, for example, acrylic acid, methacrylic acid and their lower alcohol esters, the following general formula (1),

(Wherein R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group having 8 to 20 carbon atoms), a di (meth) acryl ester, a tri (meth) acryl ester, May include styrene monomers such as styrene and divinylbenzene.

  Examples of the lower alcohol of the lower alcohol ester of acrylic acid and methacrylic acid include monohydric alcohols having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, more preferably methanol.

Moreover, in the compound represented by the general formula (1), R ² representing a higher alkyl group having 8 to 20 carbon atoms preferably has 10 to 16 carbon atoms, more preferably 12 to 14 carbon atoms. The higher alkyl group R ² may be a single alkyl group or a mixed alkyl group, but is most preferably a mixed alkyl group having 12 and 13 carbon atoms. In this case, the ratio of the alkyl group having 12 carbon atoms and the alkyl group having 13 carbon atoms, that is, the ratio of dodecyl (meth) acrylate and tridecyl (meth) acrylate is usually 20:80 to 80:20, and particularly preferably 40:60 to 60:40.

において、ｎが１〜１５、特に１〜１０のものが好ましい。 Di (meth) acrylic esters include diesters of ethylene glycol and (meth) acrylic acid, diesters of polyethylene glycol and (meth) acrylic acid, diols having 3 to 6 carbon atoms in the alkyl chain, and (meth) acrylic acid. And a diester. Examples of tri (meth) acrylic esters include triesters of triols having 3 to 6 carbon atoms in the alkyl chain and (meth) acrylic acid. In addition, as polyethyleneglycol which comprises diester of polyethyleneglycol and (meth) acrylic acid, the following general formula (2),

In which n is 1 to 15, particularly 1 to 10.

  As a method for forming a layer by polymerizing or copolymerizing the above monomers, a curing method using heat or light is generally used, but is not particularly limited. In general, in the case of thermosetting, t-butyl hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, dimyristyl peroxydicarbonate, t-butyl peroxyacetate, t- Polymerization initiators such as organic peroxides such as butyl peroxy (2-ethylhexanoate) and cumyl peroxy octoate, azo compounds such as azobisisobutyronitrile and azobiscyclohexanenitrile are added, and 50 to A method of polymerizing at 120 ° C. for 1 to 20 hours can be employed. In addition, as a polymerization initiator in the case of photocuring, ketal compounds such as benzyl methyl ketal and acetophenone diethyl ketal, ketone compounds such as α-hydroxyketone, Michler's ketone, α-hydroxycyclohexyl phenyl ketone, and benzophenones such as benzophenone A compound, a metallocene compound such as metallocene, a benzoin compound such as benzoin isopropyl ether, and the like are preferably used.

  In addition, together with the above monomers, one or more of phosphoric acid esters, aromatic carboxylic acid esters, aliphatic carboxylic acids, aliphatic carboxylic acid esters, glycols and glycol (meth) acrylates may be blended and used. From the point of preventing white turbidity when left for a long time under high temperature and high humidity.

  Examples of the polymer include polyester resins such as (meth) acrylic resin (ester of (meth) acrylic acid), polycarbonate (PC), polyethylene terephthalate (PET), polybutylene terephthalate (PBT) (crystal, non-crystalline). Crystal), polysilane, polyethersulfone, polynorbornene, epoxy resin, for example, bisphenol A type, novolac type epoxy resin and polyaminoamide, modified polyaminoamide, modified aromatic polyamine, modified aliphatic polyamine, modified alicyclic polyamine , Mixed cured products with curing agents with active hydrogen such as phenol, polyaryl, polyimide (PI), polycarbodiimide, polyetherimide, polyamideimide, polyesterimide, polyamide (PA), polystyrene (PS), polyester Styrene such as rilonitrile-styrene copolymer (AS), methyl methacrylate-styrene copolymer (MS, MMA-St), styrene-butadiene block copolymer (SBS), acrylonitrile-butadiene-styrene copolymer (ABS) Resins (among other things, SBS and ABS have the advantage of excellent impact resistance), polyarylene ethers such as polyphenylene ether, polyarylate (PAR), polyacetal, polyphenylene sulfide, polysulfone, polyether ether ketone and polyether ketone ketone Polyether ketones, polyvinyl alcohol, polyvinyl pyrrolidone, styrene-ethylene-butadiene-styrene block polymer (SEBS), vinylidene fluoride resin, hexafluoropropylene resin, Etc. can be mentioned fluorine-based resin such as fluoro-acetone resins, among others, (meth) acrylic resin is preferable.

  Other transparent resins include polyvinyl chloride (PVC), cycloolefin polymer (trade name: Arton (JSR Co., Ltd.), Zeonex (Nippon Zeon Co., Ltd., etc.), polypropylene (PP), polyethylene (PE), Examples include triacetyl cellulose (TAC) resin, polyether sulfone (PES), phenol resin, polysulfone (PSF) resin, etc. Among them, styrene resins, particularly those starting from monomers or low molecular weight materials MS resin, (meth) acrylic resin, and epoxy resin.

  In addition to copolymers of acrylic acid, methacrylic acid and their lower alcohol esters and styrenic monomers, transparent resins using monomers in which some or all of the above-described monomers are replaced with fluorine atoms, etc. Can also be used. These materials for the core layer and the upper and lower cladding layers can be used alone or in admixture of two or more. The upper cladding layer 2 and the lower cladding layer 3 are preferably formed using the same material from the viewpoint of reducing transmission loss.

  In addition, as the board | substrate 5 used in a manufacturing process, it can select from the conventionally known thing suitably and can be used, It does not restrict | limit in particular. For example, in addition to silicon substrates, quartz substrates, metal foils, glass plates, etc., polymers such as polyethylene terephthalate (PET), acrylic resin films, polycarbonate (PC) films, triacetyl cellulose (TAC) films, polyimide (PI) films, etc. A film or the like can be used. However, when the optical imprint method is used in the above-described imprint process, it is necessary to cure by irradiating light from the substrate 5 side or from the mold side. It is necessary to use it. Furthermore, the solvent used for preparing the coating solution for each layer is not particularly limited, and examples thereof include acetone, methyl ethyl ketone (MEK), ethyl acetate, cellosolve, dioxane, tetrahydrofuran (THF), benzene, cyclohexanone, and the like. The conventional organic solvent can be appropriately selected and used.

  Furthermore, in the present invention, a hard coat or a moisture absorption preventing layer may be laminated on the surface of the optical waveguide produced as described above. Since the portion that transmits information in the optical waveguide as a light path is the core layer 1, there is no problem in the performance as the optical waveguide unless the core layer 1 is damaged, but in order to prevent such a large damage. In addition, it may be necessary to provide a hard coat on the surface. Such hard coat materials include (meth) acrylate monomers such as monofunctional (meth) acrylates, bifunctional (meth) acrylates, trifunctional or higher (meth) acrylates, polyfunctional epoxies, and (meth) acrylic oligomers. , Urethane (meth) acrylate, Epoxy (meth) acrylate, Polyester (meth) acrylate, Copolymer (meth) acrylate, Epoxy oligomer added to photoinitiator to polymerize (meth) acrylate or epoxy hard coat material , Silane compounds, organometallic compounds, inorganic oxide fine particles, curing catalysts, and silicone-based hardcoat materials (other than primer treatment may be used) containing other materials as desired, organoalkoxysilanes, alkoxysilanes・ Zirconate-based, water-based Organic hard coat materials such as Kate, aqueous alumina, organoalkoxysilane / resin hybrid, alkoxysilane / zirconate / resin hybrid, water silicate / resin hybrid, and organic such as photocation curable organic / inorganic hybrid materials -Inorganic hybrid type hard coat materials.

Further, the moisture absorption preventing agent is provided for the purpose of preventing the refractive index depending on the optical waveguide material to be used, because the refractive index changes due to moisture absorption and may deviate greatly from the intended design value. In general, a material having high hydrophobicity is used for the moisture absorption preventing layer, and examples thereof include water-repellent paints and fluorine-containing compounds. Also, SiO ₂ , SiN _4, etc. can be used, and these are applied to the upper and lower surfaces of the optical waveguide (film) to prevent moisture absorption of the optical waveguide material itself. In addition, when apply | coating only to one side, anisotropy arises and it may lead to generation | occurrence | production of curvature.

Hereinafter, the present invention will be described specifically by way of examples.
An acrylic resin (manufactured by JSR) is applied on a 6-inch diameter quartz glass substrate to a thickness of 100 μm using a spin coater, and subsequently heated at 100 ° C. for 3 minutes to form the lower cladding layer 2 (refractive index). 1.51) was formed. Next, a quartz mold is prepared in which the convex side of the concavo-convex pattern follows the linear core shape of the core layer 1A shown in FIG. 3, and thermal imprinting is performed at a pressing temperature of 180 ° C., and the lower cladding layer After forming a groove for forming a core layer, a high pressure mercury lamp (365 nm) was used as a light source, and exposure was performed at an illuminance of 20 mW / cm ² and a light amount of 1.0 J / cm ² . The groove had a cross-sectional dimension of 50 μm in width and 50 μm in height, and had a linear planar shape shown in FIG.

Next, an acrylic resin having a refractive index 3% higher than that of the acrylic resin of the lower cladding layer 2 by adding epoxy acrylate as a high refractive index monomer to the acrylic resin used for the lower cladding layer 2. The resin composition is printed on the linear groove portion of the lower clad layer 2 by screen printing, heated at a temperature of 100 ° C. for 3 minutes, and then using a high pressure mercury lamp (365 nm) light source, an illuminance of 20 mW / cm ² , By exposing with a light amount of 1.0 J / cm ² , a core layer 1A having a refractive index of 1.57, a width of 50 μm, and a height of 50 μm was formed.

Next, as the upper clad layer 3, a film having a thickness of 50 μm is laminated by spin coating using the same acrylic resin as the lower clad layer 2, heated at a temperature of 100 ° C. for 3 minutes, and then a high-pressure mercury lamp (365 nm). The light source was exposed at an illuminance of 20 mW / cm ² and a light amount of 1.0 J / cm ² . Further, heating was performed at 150 ° C. for 60 minutes, and a waveguide layer A integrated with the substrate having the linear core layer 1A was produced.

  Next, the above procedure was repeated to produce a waveguide layer B integral with the substrate having the linear core layer 1B. An epoxy acrylate optical adhesive is used so that a lattice-like core layer perpendicular to each other is formed by superimposing these two waveguide layers on the two core layers 1A and 1B (see FIG. 1B). Then, the substrate and the waveguide portion were peeled off by immersing in hydrochloric acid. As a result, a film optical waveguide having a lattice-shaped core layer formed by stacking two core shapes was obtained.

While light is incident on this optical waveguide and is emitted again, the optical path is changed by 90 ° in the vertical direction, that is, from the lower core layer 1A to the upper core layer 1B or vice versa. Alternatively, a 45 ° mirror was fabricated at a location where light was emitted to an optical element existing on either the upper or lower side or a new optical waveguide. For the processing, a 90 ° V-order diamond blade with a blade tip shape was used, and cutting was performed while applying the blade perpendicular to the core layer of the optical waveguide.
Through the above series of steps, the optical waveguide of the present invention in which the core layer is formed of a plurality of layers at least partially can be manufactured.

(A) is a schematic perspective view showing only the core layer of the optical waveguide of the present invention, (b) is a schematic perspective view of the optical waveguide of the present invention, and (c) is a waveguide section through an adhesive layer. It is a schematic perspective view of the other optical waveguide of this invention which laminated | stacked. It is an example of 1 structure of the electrical / light mixed wiring board as an example of the wiring board using the optical waveguide of this invention. It is a schematic explanatory drawing which shows an example of the manufacturing process of the optical waveguide using the imprint method. It is a schematic explanatory drawing which shows an example of the manufacturing process of the optical waveguide using a photo bleach method. It is a schematic explanatory drawing which shows the other example of the manufacturing process of the optical waveguide using a photo bleach method.

Explanation of symbols

1, 1A, 1B Core layer 2 Clad layer (lower clad layer)
3 Upper clad layer 4 Groove part 5 Substrate 6 Adhesive layer 31 Light emitting element 32 Light receiving element 40 Electrical wiring layer 50 Mirror 70 Mold 101, 201 Core layer 102, 202 Clad layer 111, 211 Single layer film 112A, 112B, 212 Mask member 113A, 113B, 213 Patterning shape 214A Lower cladding layer 214B Upper cladding layer

Claims (12)

  An optical waveguide that includes a cladding layer and a core layer, and receives, propagates, and emits signal light through the core layer, includes a plurality of waveguide layers including the cladding layer and the core layer, and the plurality of waveguides. An optical waveguide comprising a waveguide layer laminated at least partially.   The optical waveguide according to claim 1, wherein the optical waveguide is disposed in an electric / light mixed wiring board together with the electric wiring portion.   The optical waveguide according to claim 2, wherein the optical waveguide is laminated with an electric wiring layer including the electric wiring portion and disposed in the electric / optical mixed wiring board.   The optical waveguide according to claim 1, wherein the plurality of waveguide layers are laminated via an adhesive or a curable resin.   The optical waveguide according to claim 1, comprising an organic compound.   6. A plurality of core layers extending substantially parallel to each other in two directions orthogonal to each other are formed on at least a part of two of the plurality of laminated waveguide layers. The optical waveguide according to claim 1.   Adhesion made of a resin having an absorption loss of 0.2 dB / cm or less in the wavelength region of light transmitted between the pair of core layers facing each other without interposing the clad layer between the laminated waveguide layers The optical waveguide according to claim 1, wherein a layer is provided.   The optical waveguide according to claim 1, wherein at least one mirror is provided in a direction that forms 45 ° with respect to the traveling direction of light.   9. The method of manufacturing an optical waveguide according to claim 1, wherein the clad layer includes a lower clad layer and an upper clad layer. The lower clad coated after the lower clad layer is coated. A mold having a concavo-convex pattern formed on the layer is pressed, and the concavo-convex pattern is transferred to the surface of the lower clad layer to form a groove in the lower clad layer, and the core layer is applied in the groove An optical waveguide manufacturing method characterized by the above.   The optical waveguide manufacturing method according to any one of claims 1 to 8, wherein a single-layer film containing a photobleaching material is covered with a mask member from one or two directions, and the single-layer film is formed on the single-layer film. On the other hand, a method of manufacturing an optical waveguide, comprising: a light irradiation step of irradiating light from one or two directions through the mask member; and a peeling step of peeling the mask member from the single layer film.   The method for manufacturing an optical waveguide according to claim 1, wherein the core layer is formed by a direct exposure method.   9. The method of manufacturing an optical waveguide according to claim 1, wherein the core layer is formed by direct drawing by irradiation with radiation.

Images