JP2008122898A - Manufacturing method of flexible optical waveguide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a flexible optical waveguide which is superior in productivity. <P>SOLUTION: The manufacturing method of the flexible optical waveguide using two clad layer forming resin films having clad layer forming resins 2 and 7 formed on base material films 1 and 8, includes a stage of peeling at least one base material film 1 or 8 of the first or second clad layer forming resin film, wherein at least one of the base material films forming the first and second clad layer forming resin films is subjected to surface treatment and the surface tension of the treated surface is 45 to 70 mN/m. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a flexible optical waveguide having excellent productivity.

  In high-speed and high-density signal transmission between electronic devices and between wiring boards, signal transmission interference and attenuation become barriers in conventional transmission using electric wiring, and the limits of high-speed and high-density are beginning to appear. In order to overcome this problem, a technique for optically connecting electronic elements and wiring boards, so-called optical interconnection, has been studied. As the optical path, a flexible optical waveguide having flexibility is considered preferable from the viewpoints of ease of coupling with elements and substrates and ease of handling.

As flexible optical waveguides, for example, Patent Document 1 and Patent Document 2 propose polymer film optical waveguides.
The manufacturing method of the polymer film optical waveguide disclosed in Patent Document 1 is as follows. First, a polymer solution or the like is spin-coated on a substrate such as silicon, and a lower cladding layer is formed by baking. After the core layer is formed by the same method, a mask pattern is formed by Si-containing photoresist or the like, the core pattern is formed by dry etching, and then the upper clad layer is formed by the same method as the method of forming the lower clad layer. Finally, the optical waveguide formed into a film is manufactured by peeling the optical waveguide from the substrate. Here, in order to facilitate the peeling of the optical waveguide, a thermally oxidized silicon substrate is used as the substrate, and after the optical waveguide is formed, a method of peeling by immersing in hydrofluoric acid is employed.

However, in the above-described film optical waveguide, the layers of the lower clad, core, and upper clad are formed by spin coating and baking, so that it takes time to form each layer, and a liquid material is applied on the substrate to form a film. Since the optical waveguide is manufactured using this method, the film thickness management is complicated. Moreover, since the resin applied on the substrate is in a liquid state before curing, the resin flows on the substrate and it is difficult to maintain the uniformity of the film thickness. There was a problem.
Further, since silicon is used for the substrate, it is not suitable for manufacturing a large number of optical waveguides having a size of 10 cm or more. Furthermore, the manufacturing method includes a dry etching process which is a high vacuum process, and in order to manufacture a multimode optical waveguide having a thick core layer, it is necessary to perform dry etching for a very long time.

  In Patent Document 2, a lower clad is formed on a convex mold, and a substrate having copper deposited on the surface is bonded onto the lower clad. Subsequently, the mold is removed, the groove formed in the trace of the convex portion of the mold is filled with the core, and an upper clad is formed so as to cover the core. Finally, the deposited copper is melted and the substrate is removed to obtain a flexible optical waveguide. However, this manufacturing method uses a mold, and the problem is that the mold is expensive and it is difficult to increase the area.

JP-A-7-239422 Japanese Patent No. 3249340

  An object of this invention is to provide the manufacturing method of the flexible optical waveguide which is excellent in productivity in view of the said problem.

As a result of intensive studies, the present inventors have obtained the above problem by using a clad layer forming resin film in which a clad layer forming resin is formed on a surface-treated base film in a method for producing a flexible optical waveguide. I found out that it could be solved.
That is, the present invention
[1] A method of manufacturing a flexible optical waveguide using two resin films for forming a clad layer in which a resin for forming a clad layer is formed on a base film, and for forming a clad layer of a first resin film for forming a clad layer A first step of curing the resin and forming a first clad layer; a second step of laminating a core layer on the first clad layer; exposing and developing the core layer; A third step of forming, a fourth step of embedding the core pattern in the second clad layer forming resin by laminating the second clad layer forming resin film, curing the clad layer forming resin, A fifth step of forming a second clad layer, a sixth step of peeling at least one of the first and second clad layer forming resin films, and the first and second steps At least one of the processed surface, a method of manufacturing a flexible optical waveguide, wherein the surface tension of the surface treated surface is 45~70mN / m of the base film constituting the resin film for forming a cladding layer,
[2] The method for manufacturing a flexible optical waveguide according to [1], wherein the second step includes laminating a resin film for forming a core layer on the first clad layer, and laminating the core layer.
[3] The method for producing a flexible optical waveguide according to [1] or [2], wherein the surface treatment is corona treatment,
[4] The method for producing a flexible optical waveguide according to any one of the above [1] to [3], wherein a humidification process is included in a sixth step of peeling the base film, and [5] the base film is The method for producing a flexible optical waveguide according to any one of the above [1] to [4], which is any one of a polyamide film, a polyethylene terephthalate film, a polyethylene naphthalate film, and a polyphenylene sulfide film,
Is to provide.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the flexible optical waveguide excellent in productivity can be provided.

  The method for producing a flexible optical waveguide of the present invention uses two clad layer forming resin films in which a clad layer forming resin is formed on a base film, and the first step to the first step described in detail below. 6 steps are included. Hereafter, the manufacturing method of the flexible optical waveguide of this invention is demonstrated in detail using FIG.

The first step in the method for producing a flexible optical waveguide of the present invention is a step of curing the clad layer forming resin of the first clad layer forming resin film to form the first clad layer (lower clad layer) 2. (See FIG. 1 (a)).
As shown in FIG. 2, the clad layer forming resin film used here is obtained by forming a clad layer forming resin 12 on a base film 13, and a protective film (separator) 14 is laminated as necessary. Structure.
In addition, the protective film is provided for the purpose of improving the winding property when manufacturing the clad layer forming resin film or in the form of a roll in the production of the clad layer forming resin film, The thing similar to what is illustrated as a base film mentioned later can be used. The protective film is preferably not subjected to an adhesive treatment such as a corona treatment in order to facilitate peeling from the clad layer forming resin film, and may be subjected to a release treatment or an antistatic treatment as necessary. .

  The base film 13 is applied with the cladding layer forming resin 12 and becomes a supporting base material in the subsequent optical waveguide manufacturing process. The material is not particularly limited, but has flexibility and toughness. From this point of view, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyethylene, polypropylene, polyamide, polycarbonate, polyphenylene ether, polyether sulfide, polyphenylene sulfide, polyarylate, liquid crystal polymer, polysulfone, polyethersulfone, poly Preferable examples include ether ether ketone, polyether imide, polyamide imide, and polyimide.

  Among these substrate films, in the production of optical waveguides, polyethylene terephthalate, polyethylene naphthalate, etc. from the viewpoint of heat resistance that can be produced, resistance to developer, ultraviolet transparency for curing the clad layer, and availability Polyester, polyamide and polyphenylene sulfide are preferably used for the base film. In particular, polyamide film, polyethylene naphthalate film and polyphenylene sulfide film are used from the viewpoint of heat resistance and low shrinkage when manufacturing an optical waveguide, and polyethylene terephthalate film is used from the viewpoint of ultraviolet transparency for curing the cladding layer. Particularly preferred.

  In the present invention, at least one of the base film constituting the first clad layer forming resin film and the base film constituting the second clad layer forming resin film described later is surface-treated. Features. By performing the surface treatment, there is an advantage that the wettability of the clad forming resin varnish is improved and the clad layer is not peeled off in the manufacturing process of the optical waveguide.

  The surface tension of the surface-treated substrate film needs to be 45 to 70 mN / m. When the surface tension of the base film is 45 mN / m or more, the wettability between the resin for forming the clad layer and the base film is sufficient, and the clad layer is not peeled off during the resin repelling or manufacturing process. On the other hand, if it is 70 mN / m or less, the substrate film can be easily peeled in the peeling step described later. From the above viewpoint, the surface tension of the base film is more preferably 48 to 62 mN / m, and further preferably 52 to 60 mN / m. Here, the surface tension is measured based on JIS-K6768.

Specific examples of the surface treatment of the substrate film include physical or chemical surface treatments such as an oxidation method and an unevenness method. Examples of the oxidation method include corona treatment, chromium oxidation treatment, flame treatment, hot air treatment, ozone / ultraviolet treatment method, and examples of the unevenness method include a sand blast method and a solvent treatment method.
Of these, corona treatment is most preferable from the viewpoints of effects and operability. The conditions for the corona treatment are not particularly limited as long as the surface tension of the base film falls within the above range.

  In the first step, when the protective film 14 is provided on the side opposite to the base film of the resin film for forming the clad layer (see FIG. 2), the protective film is peeled off and the resin film for forming the clad layer is then lighted. The first clad layer (lower clad layer) 2 is formed by curing by ultraviolet rays (UV) or the like or heating.

The clad layer forming resin used in the present invention is not particularly limited as long as it is a resin composition that has a lower refractive index than the core layer and is cured by light or heat, and includes a thermosetting resin composition and a photosensitive resin composition. Can be used.
More preferably, the clad layer forming resin is preferably composed of a resin composition containing (A) a base polymer, (B) a photopolymerizable compound, and (C) a photopolymerization initiator.

The (A) base polymer used here is for forming a clad layer and ensuring the strength of the clad layer, and is not particularly limited as long as the object can be achieved, phenoxy resin, epoxy resin, (Meth) acrylic resin, polycarbonate resin, polyarylate resin, polyether amide, polyether imide, polyether sulfone, etc., or derivatives thereof. These base polymers may be used alone or in combination of two or more.
Of the base polymers exemplified above, from the viewpoint of high heat resistance, the main chain preferably has an aromatic skeleton, and particularly preferably a phenoxy resin.
From the viewpoint of three-dimensional crosslinking and improving heat resistance, an epoxy resin, particularly an epoxy resin that is solid at room temperature is preferable. Further, compatibility with the photopolymerizable compound (B) described in detail later is important for ensuring the transparency of the resin film for forming the cladding layer. From this point, the phenoxy resin and the (meth) acrylic resin are used. Resins are preferred. Here, (meth) acrylic resin means acrylic resin and methacrylic resin.

  Among phenoxy resins, those containing bisphenol A or a bisphenol A type epoxy compound or a derivative thereof, and bisphenol F or a bisphenol F type epoxy compound or a derivative thereof as a constituent unit of a copolymer component are heat resistant, adhesive and soluble. It is preferable because of its excellent properties. Preferred examples of the bisphenol A or bisphenol A type epoxy compound include tetrabromobisphenol A and tetrabromobisphenol A type epoxy compounds. Moreover, as a derivative of bisphenol F or a bisphenol F-type epoxy compound, tetrabromobisphenol F, a tetrabromobisphenol F-type epoxy compound, etc. are mentioned suitably. Specific examples of the bisphenol A / bisphenol F copolymer type phenoxy resin include “Phenotote YP-70” (trade name) manufactured by Toto Kasei Co., Ltd.

  Examples of the epoxy resin that is solid at room temperature include, for example, “Epototo YD-7020, Epototo YD-7019, Epototo YD-7007” (all trade names) manufactured by Toto Chemical Co., Ltd., and “Epicoat 1010” manufactured by Japan Epoxy Resins Co., Ltd. Bisphenol A type epoxy resin such as “Epicoat 1009, Epicoat 1008” (both trade names).

  (A) The molecular weight of the base polymer is preferably 5,000 or more in terms of number average molecular weight, more preferably 10,000 or more, and particularly preferably 30,000 or more, from the viewpoint of film formability. Although there is no restriction | limiting in particular about the upper limit of a number average molecular weight, From a compatible viewpoint with (B) photopolymerizable compound and exposure developability, it is preferable that it is 1,000,000 or less, Furthermore, 500,000 Hereinafter, it is particularly preferably 200,000 or less. The number average molecular weight in the present invention is a value measured by gel permeation chromatography (GPC) and converted to standard polystyrene.

  (A) It is preferable that the compounding quantity of a base polymer shall be 10-80 mass% with respect to the total amount of (A) component and (B) component. When the blending amount is 10% by mass or more, there is an advantage that it is easy to form a thick film having a thickness of about 50 to 500 μm necessary for forming an optical waveguide. Progresses sufficiently. From the above viewpoint, the blending amount of (A) the base polymer is more preferably 20 to 70% by mass.

  Next, (B) the photopolymerizable compound is not particularly limited as long as it is polymerized by irradiation with light such as ultraviolet rays, and a compound having two or more epoxy groups in the molecule or an ethylenic non-polymer in the molecule. Examples thereof include compounds having a saturated group.

  Specific examples of compounds having two or more epoxy groups in the molecule include bisphenol A type epoxy resins, tetrabromobisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AD type epoxy resins, naphthalene type epoxy resins, etc. Bifunctional aromatic glycidyl ether; phenol novolac type epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene-phenol type epoxy resin, tetraphenylol ethane type epoxy resin, etc. polyfunctional aromatic glycidyl ether; polyethylene glycol type epoxy resin, Bifunctional aliphatic glycidyl ether such as polypropylene glycol type epoxy resin, neopentyl glycol type epoxy resin, hexanediol type epoxy resin; hydrogenated bisphenol A type epoxy Bifunctional alicyclic glycidyl ethers such as resins; polyfunctional aliphatic glycidyl ethers such as trimethylolpropane type epoxy resins, sorbitol type epoxy resins and glycerin type epoxy resins; bifunctional aromatic glycidyl esters such as phthalic acid diglycidyl esters; Bifunctional alicyclic glycidyl esters such as tetrahydrophthalic acid diglycidyl ester and hexahydrophthalic acid diglycidyl ester; bifunctional aromatic glycidyl amines such as N, N-diglycidylaniline and N, N-diglycidyltrifluoromethylaniline N, N, N ′, N′-tetraglycidyl-4,4-diaminodiphenylmethane, 1,3-bis (N, N-glycidylaminomethyl) cyclohexane, N, N, O-triglycidyl-p-aminophenol Polyfunctional aromatic glycidi such as Amines; bifunctional alicyclic epoxy resins such as alicyclic diepoxy acetals, alicyclic diepoxy adipates, alicyclic diepoxy carboxylates, vinylcyclohexene dioxide; bifunctional heterocyclic epoxy resins such as diglycidyl hydantoin A polyfunctional heterocyclic epoxy resin such as triglycidyl isocyanurate; a bifunctional or polyfunctional silicon-containing epoxy resin such as an organopolysiloxane type epoxy resin;

  These compounds having two or more epoxy groups in the molecule usually have a molecular weight of about 100 to 2,000, more preferably about 150 to 1,000, and those that are liquid at room temperature are suitably used. Moreover, these compounds can be used individually or in combination of 2 or more types, Furthermore, it can also be used in combination with another photopolymerizable compound. In addition, the molecular weight of the photopolymerizable compound in the present invention can be measured by GPC method or mass spectrometry.

  Specific examples of the compound having an ethylenically unsaturated group in the molecule include (meth) acrylate, vinylidene halide, vinyl ether, vinyl pyridine, vinyl phenol, etc. Of these, transparency and heat resistance are included. From the viewpoint, (meth) acrylate is preferable, and any of monofunctional, bifunctional, trifunctional or higher can be used.

  Monofunctional (meth) acrylates include methoxypolyethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, lauryl (meth) acrylate, isostearyl (meth) acrylate, and 2- (meth) acryloyloxyethyl succinic acid. , Paracumylphenoxyethylene glycol (meth) acrylate, 2-tetrahydropyranyl (meth) acrylate, isobornyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, benzyl (meth) acrylate Etc.

  As the bifunctional (meth) acrylate, ethoxylated 2-methyl-1,3-propanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) Acrylate, 2-methyl-1,8-octanediol diacrylate, 1,9-nonanediol di (meth) acrylate, 1,10-nonanediol di (meth) acrylate, ethoxylated polypropylene glycol di (meth) acrylate, propoxy Ethoxylated bisphenol A diacrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol Di (meth) acrylate, ethoxylated bisphenol A di (meth) acrylate, tricyclodecane di (meth) acrylate, ethoxylated cyclohexanedimethanol di (meth) acrylate, 2-hydroxy-1-acryloxy-3-methacryloxypropane, 2-hydroxy-1,3-dimethacryloxypropane, 9,9-bis [4- (2-acryloyloxyethoxy) phenyl] fluorene, 9,9-bis [3-phenyl-4-acryloylpolyoxyethoxy) fluorene Bisphenol A type, phenol novolak type, cresol novolak type, glycidyl ether type epoxy (meth) acrylate, and the like.

  Furthermore, as tri- or more functional (meth) acrylates, ethoxylated isocyanuric acid tri (meth) acrylate, ethoxylated glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethoxylated trimethylolpropane tri (meth) Acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, propoxylated pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, caprolactone modified ditri Examples include methylolpropane tetraacrylate and dipentaerythritol hexa (meth) acrylate. These can be used alone or in combination of two or more.

  Here, (meth) acrylate means acrylate and methacrylate. The blending amount of the (B) photopolymerizable compound is preferably 20 to 90% by mass with respect to the total amount of the component (A) and the component (B). When the blending amount is 20% by mass or more, the base polymer can be easily entangled and cured, and when it is 90% by mass or less, a sufficiently thick clad layer can be easily formed. it can. From the above viewpoint, the blending amount of the photopolymerizable compound (B) is more preferably 30 to 80% by mass.

  Next, there is no restriction | limiting in particular as a photoinitiator of (C) component, For example, as an initiator of an epoxy compound, aryl diazonium salts, such as p-methoxybenzenediazonium hexafluorophosphate; diphenyliodonium hexafluorophosphonium salt, diphenyliodonium Diaryl iodonium salts such as hexafluoroantimonate salt; triphenylsulfonium hexafluorophosphonium salt, triphenylsulfonium hexafluoroantimonate salt, diphenyl-4-thiophenoxyphenylsulfonium hexafluoroantimonate salt, diphenyl-4-thiophenoxyphenylsulfonium Hexafluoroantimonate salt, diphenyl-4-thiophenoxyphenylsulfonium pentafluorohydroxyantimonate salt A triarylsulfonium salt; a triphenylselenonium hexafluorophosphonium salt, a triphenylselenonium borofluoride salt, a triarylselenonium salt such as a triphenylselenonium hexafluoroantimonate salt; a dimethylphenacylsulfonium hexafluoroantimonate salt; Dialkylphenazylsulfonium salts such as diethylphenacylsulfonium hexafluoroantimonate salt; dialkyl-4-hydroxyphenylsulfonium salts such as 4-hydroxyphenyldimethylsulfonium hexafluoroantimonate salt, 4-hydroxyphenylbenzylmethylsulfonium hexafluoroantimonate salt Α-hydroxymethylbenzoin sulfonate ester, N-hydroxyimide sulfonate, α-sulfonyloxy Ketones, such as sulfonic acid esters, such as β- sulfo Niro carboxymethyl ketone.

  Moreover, as an initiator of the compound having an ethylenically unsaturated group in the molecule, benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone (Michler ketone), N, N′-tetraethyl-4,4 '-Diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 2,2-dimethoxy-1,2 -Diphenylethane-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy- 2-Methyl-1-propan-1-one, 1,2-methyl-1- [4- (methylthio) phenyl] -2- Aromatic ketones such as ruphorinopropan-1-one; 2-ethylanthraquinone, phenanthrenequinone, 2-tert-butylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone 2,3-diphenylanthraquinone, 1-chloroanthraquinone, 2-methylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, 2-methyl-1,4-naphthoquinone, 2,3-dimethylanthraquinone, etc. Quinones; benzoin ether compounds such as benzoin methyl ether, benzoin ethyl ether, and benzoin phenyl ether; benzoin compounds such as benzoin, methyl benzoin, and ethyl benzoin; 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di (methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) ) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer, etc. 2,4,5-triarylimidazole dimer; bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine Phosphine oxides such as oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide; Examples include acridine derivatives such as 9-phenylacridine and 1,7-bis (9,9'-acridinyl) heptane; N-phenylglycine, N-phenylglycine derivatives, and coumarin compounds. In addition, in the 2,4,5-triarylimidazole dimer, the aryl group substituents of two 2,4,5-triarylimidazoles may give the same and symmetric compounds, or differently asymmetric Such compounds may be provided. Moreover, you may combine a thioxanthone type compound and a tertiary amine compound like the combination of diethyl thioxanthone and dimethylaminobenzoic acid. Of these compounds, aromatic ketones and phosphine oxides are preferred from the viewpoint of improving the transparency of the core layer and the cladding layer. These (C) photopolymerization initiators can be used alone or in combination of two or more.

  (C) It is preferable that the compounding quantity of a photoinitiator shall be 0.1-10 mass parts with respect to 100 mass parts of total amounts of (A) component and (B) component. If it is 0.1 parts by mass or more, the photosensitivity is sufficient, while if it is 10 parts by mass or less, only the surface of the optical waveguide is selectively cured, the curing does not become insufficient, It is preferable that the propagation loss does not increase due to absorption of the photopolymerization initiator itself. From the above viewpoint, the blending amount of (C) the photopolymerization initiator is more preferably 1 to 5 parts by mass.

  In addition to the above, the clad layer forming resin of the present invention contains an antioxidant, an anti-yellowing agent, an ultraviolet absorber, a visible light absorber, a colorant, a plasticizer, a stabilizer, and a filler as necessary. You may add what is called additives, such as an agent, in the ratio which does not have a bad influence on the effect of this invention.

  The resin film for forming a clad layer can be easily produced by dissolving a resin composition containing the components (A) to (C) in a solvent, applying the resin composition to the base film, and removing the solvent. The solvent used here is not particularly limited as long as it can dissolve the resin composition. For example, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N, N-dimethylacetamide, propylene glycol monomethyl ether, A solvent such as propylene glycol monomethyl ether acetate, cyclohexanone, N-methyl-2-pyrrolidone, or a mixed solvent thereof can be used. The solid content concentration in the resin solution is preferably about 30 to 80% by mass.

  Regarding the thickness of the first cladding layer, the thickness after drying is preferably in the range of 5 to 500 μm. When the thickness is 5 μm or more, a clad thickness necessary for light confinement can be secured, and when the thickness is 500 μm or less, it is easy to control the film thickness uniformly. From the above viewpoint, the thickness of the cladding layer is preferably in the range of 10 μm to 100 μm.

  Further, the first clad layer (lower clad layer) formed first and the second clad layer (upper clad layer) for embedding a core pattern described later may be the same or different. However, in order to embed the core pattern, it is preferable that the thickness of the second cladding layer (upper cladding layer) is larger than the thickness of the core layer.

Next, the 2nd process in the manufacturing method of this invention is a process of laminating | stacking a core layer on a 1st clad layer (lower clad layer). There are no particular restrictions on the method of laminating the core layer, the resin composition for forming the core layer is dissolved in a solvent, etc., applied to the first cladding layer by spin coating or the like, and dried to dry the core layer. Can be formed.
Alternatively, a method of laminating a core layer forming resin film on the first clad layer (lower clad layer) and laminating the core layer may be used (see FIG. 1B). That is, in this second step, a core layer having a higher refractive index than that of the cladding layer is laminated on the above-described first cladding layer by thermocompression bonding of the core layer forming resin film. Here, the core layer-forming resin film includes those in which the core layer-forming resin is formed on the base film or those composed of the core layer-forming resin alone. It is easier to handle and it is preferable to use a resin in which a core layer forming resin is formed. More specifically, a configuration as shown in FIG. That is, the core layer-forming resin 22 is formed on the base film 23, and for the purpose of protecting the core layer-forming resin film and improving the roll-up property when manufactured into a roll, as desired. A protective film 24 is provided on the opposite side of the base film 23. As a protective film, the thing similar to what was mentioned as an example as a base film of the said resin film for clad layer formation can be used.
The protective film and the base film are preferably not subjected to an adhesion treatment such as a corona treatment in order to facilitate peeling from the core layer forming resin film, and are subjected to a release treatment or an antistatic treatment as necessary. May be.

When laminating the core layer-forming resin film, it is preferable to laminate the core layer-forming resin film under reduced pressure from the viewpoint of adhesion and followability. The heating temperature here is preferably 50 to 130 ° C., and the pressure bonding pressure is preferably about 0.1 to 1.0 MPa (1 to 10 kgf / cm ² ). There is no particular limitation.

  The resin film for forming a core layer used in the present invention can use a resin composition that is designed so that the core layer has a higher refractive index than that of the cladding layer and can form a core pattern with actinic rays. Compositions are preferred. Specifically, it is preferable to use the same resin composition as that used in the clad layer forming resin. That is, it is a resin composition containing the components (A), (B) and (C) and optionally containing the optional components.

  The resin film for forming a core layer can be easily produced by dissolving a resin composition containing the components (A) to (C) in a solvent, applying the resin composition to a base film, and removing the solvent. The solvent used here is not particularly limited as long as it can dissolve the resin composition. For example, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N, N-dimethylformamide, N, N-dimethyl A solvent such as acetamide, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, cyclohexanone, N-methyl-2-pyrrolidone, or a mixed solvent thereof can be used. The solid content concentration in the resin solution is usually preferably about 30 to 80% by mass.

  The thickness of the resin film for forming the core layer is not particularly limited, and the thickness of the core layer after drying is usually adjusted to be 10 to 100 μm. When the thickness of the core layer is 10 μm or more, there is an advantage that the alignment tolerance can be increased in the coupling with the light emitting / receiving element or the optical fiber after the optical waveguide is formed, and when the thickness is 100 μm or less, the light receiving / emitting after the optical waveguide is formed. In coupling with an element or an optical fiber, there is an advantage that coupling efficiency is improved. From the above viewpoint, the thickness of the film is preferably in the range of 30 to 70 μm.

When the core layer-forming resin film is obtained by forming the core layer-forming resin on the base film, the base film and the core layer-forming resin film are composed of the core layer-forming resin alone. In this case, the material of the base film used in the process of manufacturing the resin film for forming the core layer is not particularly limited, but it is easy to peel off later, and has a viewpoint of heat resistance and solvent resistance. Preferred examples thereof include polyesters such as polyethylene terephthalate, polypropylene, and polyethylene.
Moreover, it is preferable that the thickness of this base film is 5-50 micrometers. When it is 5 μm or more, there is an advantage that the strength as a support is easily obtained, and when it is 50 μm or less, there is an advantage that a gap with the mask at the time of pattern formation becomes small and a finer pattern can be formed. From the above viewpoint, the thickness of the base film is more preferably in the range of 10 to 40 μm, and particularly preferably 15 to 30 μm.

Moreover, it is preferable to use a highly transparent flexible base material in order to improve the transmittance of exposure light and reduce the side wall roughness of the core pattern. The haze value of the highly transparent base film is preferably 5% or less, more preferably 3% or less, and particularly preferably 2% or less. The haze value is measured according to JIS K7105, and can be measured with a commercially available turbidimeter such as NDH-1001DP (manufactured by Nippon Denshoku Industries Co., Ltd.). Such a base film is available from Toyobo Co., Ltd. under the trade names “Cosmo Shine A1517” and “Cosmo Shine A4100”.
In addition, in order to make peeling easily, the said base film may be subjected to mold release treatment, antistatic treatment or the like.

  The third step in the production method of the present invention is a step of exposing and developing the core layer to form a core pattern of the optical waveguide (see FIG. 1C). Specifically, actinic rays are irradiated in an image form through the negative mask pattern 5. Examples of the active light source include known light sources that effectively emit ultraviolet rays, such as carbon arc lamps, mercury vapor arc lamps, ultrahigh pressure mercury lamps, high pressure mercury lamps, and xenon lamps. In addition, those that effectively emit visible light, such as a photographic flood bulb and a solar lamp, can be used.

  Next, after the post-exposure heating as necessary, if the base film 4 of the core layer forming resin film remains, the base film is peeled off, and the unexposed portion is removed by wet development or the like. Then, an optical waveguide pattern is formed (see FIG. 1D). In the case of wet development, development is performed by a known method such as spraying, rocking dipping, brushing, scraping, or the like, using an organic solvent developer suitable for the composition of the film.

  Examples of organic solvent developers include N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone, γ-butyrolactone, methyl cellosolve, ethyl cellosolve, propylene glycol monomethyl. Examples include ether and propylene glycol monomethyl ether acetate. These organic solvents may be added with water in the range of 1 to 20 parts by mass to prevent ignition. Moreover, you may use together 2 or more types of image development methods as needed.

  Examples of the development method include a dip method, a battle method, a spray method such as a high-pressure spray method, brushing, and scraping. The high-pressure spray method is most suitable for improving the resolution.

As the treatment after development, the optical waveguide pattern may be further cured and used by heating at about 60 to 250 ° C. or exposure at about 0.1 to 1000 mJ / cm ² as necessary.

  The fourth step in the production method of the present invention is a step of embedding the core pattern in the second clad layer forming resin by laminating the second clad layer forming resin film, and the fifth step is This is a step of curing the clad layer forming resin of the clad layer forming resin film 2 to form a second clad layer (see FIG. 1 (e)). At this time, the thickness of the second cladding layer 7 is preferably larger than the thickness of the core layer (core pattern 6). The second clad layer forming resin can be cured by light or heat in the same manner as the first clad layer is formed.

The second clad layer forming resin film used here is the same as the first clad layer forming resin film, and as shown in FIG. 2, the clad layer forming resin 12 is laminated on the base film 13. The protective film (separator) 14 is laminated as necessary. The material of the base film 13 is the same as that of the base film in the first clad layer forming resin film. Further, the clad layer forming resin is the same as the clad layer forming resin in the first clad layer forming resin film.
In the present invention, at least one of the base film constituting the first clad layer forming resin film and the base film constituting the second clad layer forming resin film is surface-treated as described above. Although it is characterized, it is more preferable that both are surface-treated.

Also in the base film of the second clad layer forming resin film, the surface tension of the surface-treated base film is the same as that of the base film of the first clad layer forming resin film, and is 45 to 70 mN. / M, more preferably 48 to 62 mN / m, and still more preferably 52 to 60 mN / m. The surface treatment method is the same as that of the base film in the first clad layer forming resin film, and corona treatment is particularly preferred.
In addition, when a protective film is provided on the opposite side of the base film of the second clad layer forming resin film (see FIG. 2), the protective film is peeled off and then the clad layer forming resin film is lighted or heated. To form a second cladding layer. The protective film is preferably not subjected to adhesion treatment in order to facilitate peeling from the clad layer forming resin film, and may be subjected to mold release treatment or charging treatment as necessary.

The 6th process in the manufacturing method of this invention is a process of peeling at least one base film among the 1st and 2nd resin films for clad layer formation (FIG.1 (f)). The base film is peeled off after the second clad layer (upper clad layer) of the flexible optical waveguide is formed.
In the present invention, the base film of the resin film for forming a clad layer also serves as a support in the manufacturing process of the flexible optical waveguide. Since this base film can be larger than a silicon substrate or the like conventionally used as a support, it is easy to increase the area and provides a method for manufacturing a flexible optical waveguide with excellent productivity. be able to.
The base film may be left on one side of the flexible optical waveguide, but a flexible optical waveguide with less warpage can be produced by using a symmetrical structure in which both sides are peeled off. Moreover, the flexible optical waveguide can be thinned by peeling the base film.

  Moreover, it is preferable that a humidification process is included in the process of peeling a base film. This is because the humidification treatment can reduce the adhesion between the base film and the clad layer and can easily peel the base film without damaging the optical waveguide. The humidification treatment is preferably performed under high temperature and high humidity conditions, boiling conditions, pressure cooker conditions, and the like, since the treatment time can be shortened when heating is used in combination.

  According to the above-described manufacturing method, it is possible to easily manufacture the flexible optical waveguide, which has been a conventional problem.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

Example 1
[Fabrication of flexible optical waveguide]
(Varnish formulation)
The resin composition for a core layer and a clad layer was prepared with the formulation shown in Table 1. To this was added propylene glycol monomethyl ether acetate as a solvent, 35 parts by mass with respect to the total amount for the core layer, and 40 parts by mass with respect to the total amount for the clad layer, to prepare a resin varnish. The core resin varnish is a filter with a pore size of 0.5 μm (Advantech Toyo Co., Ltd., trade name J050), and the cladding resin varnish is a filter with a pore diameter of 2 μm (Advantech Toyo Corp., trade name PF020). Filtration was performed under a pressure of 3 MPa, and vacuum degassing was performed.

* 1 Phenototoy YP-70; manufactured by Tohto Kasei Co., Ltd., bisphenol A / bisphenol F copolymer phenoxy resin * 2 A-BPEF; manufactured by Shin-Nakamura Kogyo Co., Ltd., 9,9-bis [4- (2- Acryloyloxyethoxy) phenyl] fluorene * 3 EA-1020; manufactured by Shin-Nakamura Kogyo Co., Ltd., bisphenol A type epoxy acrylate * 4 KRM-2110; manufactured by Shin-Nakamura Kogyo Co., Ltd., alicyclic diepoxycarboxylate * 5 Irgacure 819; manufactured by Ciba Specialty Chemicals Co., Ltd., bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide * 6 Irgacure 2959; manufactured by Ciba Specialty Chemicals Co., Ltd., 1- [4- (2- Hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-pro Down-1-one * 7 SP-170; Asahi Denka Co., triphenylsulfonium hexafluoroantimonate salt * 8 SP-100; manufactured by Asahi Denka Co., photosensitizer

(Production of optical waveguide forming resin film)
A polyamide film (trade name: Miktron, manufactured by Toray Industries, Inc., thickness: 12 μm) was used as the base film, and a coating machine (multicoater M-200, on the corona-treated surface (surface tension 56 mN / m)) was used. The resin resin varnish for clad was applied using Hirano Tech Seed Co., Ltd. and dried at 80 ° C. for 10 minutes and then at 100 ° C. for 10 minutes to prepare a resin film for forming a clad layer. Similarly, a core resin varnish was prepared on a non-treated surface of a PET film (trade name: Cosmo Shine A1517, manufactured by Toyobo Co., Ltd., thickness: 16 μm) to obtain a core layer forming resin film. At this time, the thickness of the resin layer can be arbitrarily adjusted by adjusting the gap of the coating machine. In this embodiment, the thickness after curing is 20 μm for the lower cladding layer, 70 μm for the upper cladding layer, and the core layer. It adjusted so that it might be set to 50 micrometers.

(Production of optical waveguide)
The resin film for forming the lower clad layer was photocured by irradiating 1000 mJ / cm ^{2 of} ultraviolet rays (wavelength 365 nm) with an ultraviolet exposure machine (EXM-1172, manufactured by Oak Manufacturing Co., Ltd.) and then heating at 80 ° C. for 10 minutes (see FIG. 1 (a)). Next, a core layer is formed on the clad layer using a vacuum pressure laminator (MVLP-500, manufactured by Meiki Seisakusho Co., Ltd.) under the conditions of pressure 0.4 MPa, temperature 50 ° C., and pressurization time 30 seconds. A resin film was laminated (see FIG. 1B). Subsequently, ultraviolet rays (wavelength 365 nm) are irradiated with 1000 mJ / cm ² with a UV mask (negative type) with a width of 50 μm (see FIG. 1 (c)), and post-exposure heating (PEB) is performed immediately after that. After 5 minutes at ° C., the core pattern was developed with a mixed solvent of 8 to 2 mass ratio of propylene glycol monomethyl ether acetate and N, N-dimethylacetamide (see FIG. 1 (d)). Isopropyl alcohol was used for washing the developer.
Next, an upper clad forming resin film was laminated under the same laminating conditions, followed by ultraviolet irradiation and heat treatment at 160 ° C. for 1 hour to produce a flexible optical waveguide having a base film disposed outside (FIG. 1 ( e)). Furthermore, the flexible optical waveguide was processed for 100 hours under high temperature and high humidity conditions of 85 ° C./85% for peeling the polyamide film, and then the flexible optical waveguide was prepared by peeling off and removing the base film.

  In addition, when the refractive index of the core layer and the clad layer was measured by a prism coupler (Model2010) manufactured by Metricon, the core layer was 1.584 and the clad layer was 1.550 at a wavelength of 830 nm. Further, the propagation loss of the manufactured optical waveguide was determined by using a cut-back method using a surface emitting laser (850 nm, manufactured by EXFO, FLS-300-01-VCL) as a light source, and Q82214 manufactured by Advantest Co., Ltd. as a light receiving sensor. (Measurement waveguide length 5, 3, 2 cm, incident fiber: GI-50 / 125 multimode fiber (NA = 0.20), output fiber: SI-114 / 125 (NA = 0.22)) 0.09 dB / cm.

Example 2
In Example 1, a polyethylene terephthalate film (trade name: Lumirror S105, manufactured by Toray Industries, Inc., thickness: 25 μm) was used as the base film of the resin film for forming the clad layer, and when the upper clad layer was formed. A flexible optical waveguide was produced in the same manner as in Example 1 except that the heat treatment was changed to 120 ° C. for 1 hour. As a result, it was confirmed that a flexible optical waveguide can also be produced in this example. The surface tension of the corona-treated surface of the polyethylene terephthalate film was 54 mN / m.

Example 3
In Example 1, a polyethylene naphthalate film (trade name: Teonex Q83, manufactured by Teijin DuPont Films, Inc., thickness: 25 μm) was used as the base film of the resin film for forming the clad layer, and the upper clad layer A flexible optical waveguide was produced in the same manner as in Example 1 except that the heat treatment during formation was changed to 120 ° C. for 1 hour. As a result, it was confirmed that a flexible optical waveguide can also be produced in this example. The surface tension of the corona-treated surface of the polyethylene naphthalate film was 56 mN / m.

Example 4
In Example 1, a polyphenylene sulfide film (trade name: Torelina, manufactured by Toray Industries, Inc., thickness: 9 μm) was used as a base film of a resin film for forming a cladding layer, and heating at the time of forming an upper cladding layer A flexible optical waveguide was produced in the same manner as in Example 1 except that the treatment was changed to 120 ° C. for 1 hour. As a result, it was confirmed that a flexible optical waveguide can also be produced in this example. The surface tension of the corona-treated surface of the polyphenylene sulfide film was 60 mN / m.

Comparative Example 1
In the production of a resin film for forming an optical waveguide, a clad resin varnish is produced on a non-treated surface (surface tension 35.0 mN / m) of a polyamide film (trade name: Miktron, manufactured by Toray Industries, Inc., thickness: 12 μm). A flexible optical waveguide was manufactured in the same manner as in Example 1 except that. As a result, peeling occurred at the interface between the lower clad layer and the polyamide film in the development process, and the optical waveguide could not be produced.

Comparative Example 2
In the production of a resin film for forming an optical waveguide, the resin varnish for cladding is on a non-treated surface (surface tension 43.0 mN / m) of a polyethylene terephthalate film (trade name: Lumirror S105, manufactured by Toray Industries, Inc., thickness: 25 μm). A flexible optical waveguide was produced in the same manner as in Example 1 except that it was produced. As a result, peeling occurred at the interface between the lower clad layer and the polyethylene terephthalate film in the development process, and the optical waveguide could not be manufactured.

Comparative Example 3
In the production of an optical waveguide forming resin film, a non-treated surface (surface tension 43.0 mN / surface) of a polyethylene naphthalate film (trade name: Teonex Q51, manufactured by Teijin DuPont Films, Inc., thickness: 25 μm) is used as a clad resin varnish. m) A flexible optical waveguide was produced in the same manner as in Example 1 except that it was prepared above. As a result, peeling occurred at the interface between the lower clad layer and the polyethylene naphthalate film in the development process, and the optical waveguide could not be produced.

Comparative Example 4
In the production of a resin film for forming an optical waveguide, a clad resin varnish is placed on a non-treated surface (surface tension 38.0 mN / m) of a polyphenylene sulfide film (trade name: Torelina, manufactured by Toray Industries, Inc., thickness: 9 μm). A flexible optical waveguide was manufactured in the same manner as in Example 1 except that it was manufactured. As a result, peeling occurred at the interface between the lower clad layer and the polyphenylene sulfide film in the development process, and the optical waveguide could not be produced.

  According to the present invention, it is possible to manufacture a flexible optical waveguide with high productivity.

It is a figure explaining the manufacturing method of the flexible optical waveguide of this invention. It is a figure explaining the resin film for clad layer formation used for manufacture of the flexible optical waveguide of this invention. It is a figure explaining the resin film for core layer formation used for manufacture of the flexible optical waveguide of this invention.

Explanation of symbols

1, 8; base film (for clad layer)
2; lower clad layer 3; core layer 4; base film (for core layer formation)
5; Photomask 6; Core pattern 7; Upper clad layer 11; Cladding layer forming resin film 12; Cladding layer forming resin 13; Base film 14; Protective film (separator)
21; Core layer forming resin film 22; Core layer forming resin 23; Base film 24; Protective film (separator)

Claims (5)

  A method of manufacturing a flexible optical waveguide using two clad layer forming resin films in which a clad layer forming resin is formed on a base film, and curing the clad layer forming resin of the first clad layer forming resin film A first step of forming a first cladding layer; a second step of stacking a core layer on the first cladding layer; and exposing and developing the core layer to form a core pattern of an optical waveguide. Step 4, the fourth step of embedding the core pattern in the second clad layer forming resin by laminating the second clad layer forming resin film, curing the clad layer forming resin, A fifth step of forming a cladding layer, a sixth step of peeling at least one of the first and second cladding layer-forming resin films, and the first and second layers. Tsu least one of the base film constituting the resin film for de layer formed is processed surface, method of manufacturing a flexible optical waveguide, wherein the surface tension of the surface treated surface is 45~70mN / m.   The method of manufacturing a flexible optical waveguide according to claim 1, wherein the second step includes laminating a resin film for forming a core layer on the first clad layer, and laminating the core layer.   The method for manufacturing a flexible optical waveguide according to claim 1, wherein the surface treatment is a corona treatment.   The manufacturing method of the flexible optical waveguide in any one of Claims 1-3 including a humidification process in the 6th process of peeling the said base film.   The method for producing a flexible optical waveguide according to claim 1, wherein the substrate film is any one of a polyamide film, a polyethylene terephthalate film, a polyethylene naphthalate film, and a polyphenylene sulfide film.

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