JP2005208563A - Hardening resin composition for optical waveguide, hardening dry film for forming optical waveguide, and optical waveguide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hardening dry film obtaining an optical waveguide without degrading the processability of a coating film and a mechanical property. <P>SOLUTION: The hardening resin composition for the optical waveguide contains; (A) an urethane compound containing a carboxyl group which is a reactant of a polyhydroxylic acid compound (a) containing two or more hydroxyl groups in one molecule and one or more carboxyl groups in one molecule with a polyisocyanate compound (b); (B) a polymerizable unsaturated compound; (C) a compound containing two or more ring-opening polymerizable functional groups in a molecule; and (D) a radiation polymerization initiator as essential components. The hardening dry film formed of the hardening resin composition has the softening temperature of 0 to 80°C. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a curable resin composition for an optical waveguide, a curable dry film for forming an optical waveguide, and an optical waveguide.

  2. Description of the Related Art In recent years, optical waveguides have attracted attention as optical transmission media because of demands for large capacity and high speed information processing in optical communication systems and computers. A typical example of such an optical waveguide is a quartz-based waveguide. However, there are problems that a special manufacturing apparatus is required and manufacturing time is long.

  A dry film containing a component capable of radiation polymerization is laminated on a substrate, irradiated with a predetermined amount of light, cured at a predetermined location, and developed an unexposed portion as necessary, such as a core portion. There has been proposed a method of manufacturing an optical waveguide having excellent transmission characteristics by forming the above. In other words, as an alternative to the previously described quartz-based waveguide and its manufacturing method, an optical waveguide can be formed in a short time and at a low cost simply by laminating a film on a substrate and developing it after irradiating a predetermined amount of light. A radiation curable dry film for forming an optical waveguide and a method for manufacturing an optical waveguide using the same have been proposed (Patent Document 1).

Further, as a resin composition for forming an optical waveguide, an ethylenically unsaturated group-containing carboxylic acid resin having at least one ethylenically unsaturated group and at least one carboxyl group in the molecule, a diluent, and a photopolymerization initiator There is known a resin composition for optical waveguides that contains bismuth (Patent Document 2).
Japanese Patent Laid-Open No. 15-202437 Japanese Patent Laid-Open No. 15-149475

  The dry film described in Patent Document 1 is obtained from a carboxyl group-containing radical polymerizable compound and other radical polymerizable compounds as the alkali-developable carboxyl group-containing resin component constituting the film, and its softening temperature. Describes copolymers with a temperature of 20 to 150 ° C.

  However, when the above-mentioned carboxyl group-containing resin is used as a dry film for forming an optical waveguide, the composition is coated on a release paper such as PET and laminated, or the laminated dry film is wound up. In a handling operation such as forming an optical waveguide by pasting on a base material, the dry film sometimes causes defects such as cracks and cracks, thereby reducing the performance of the optical waveguide.

  The resin composition for optical waveguides described in Patent Document 2 has no description of using this composition as a dry film for forming optical waveguides, but the above-mentioned Patent Document 1 may be used even if this composition is used as a dry film for forming optical waveguides. In the same way as the above, when this composition is coated on a release paper such as PET and laminated, the laminated dry film is taken up, or it is attached to a substrate to form an optical waveguide. In the work, the dry film sometimes generates defects such as cracks and cracks, thereby reducing the performance of the optical waveguide. Further, even when the optical waveguide resin composition described in Patent Document 2 is used as a solution, the optical properties obtained because the mechanical properties such as workability and bending of the finally obtained optical waveguide are not sufficient. When the waveguide is attached to a required place or processed, defects such as cracks and cracks may occur, which may deteriorate the performance of the optical waveguide.

  An object of this invention is to provide the curable dry film for optical waveguide formation from which an optical waveguide is obtained, especially without reducing the workability and mechanical property of a coating film.

  The curable resin composition for an optical waveguide according to the present invention comprises (A) a carboxyl group-containing urethane compound, (B) a polymerizable unsaturated compound, and (C) two or more ring-opening polymerizable functional groups in the molecule. It contains a compound and (D) a radiation polymerization initiator as essential components.

  The curable resin composition for an optical waveguide according to the present invention is such that (A) a carboxyl group-containing urethane compound contains two or more hydroxyl groups in one molecule and one or more carboxyl groups in one molecule. It is a reaction product of an acid compound (a) and a polyisocyanate compound (b).

  The curable dry film for forming an optical waveguide according to the present invention comprises (A) a carboxyl group-containing urethane compound, (B) a polymerizable unsaturated compound, and (C) two or more ring-opening polymerizable functional groups in the molecule. A dry film for forming an optical waveguide comprising a compound and (D) a curable resin composition containing a radiation polymerization initiator as an essential component, wherein the softening temperature of the dry film is 0 ° C to 80 ° C It is the dry film for optical waveguide formation characterized.

  An optical waveguide according to the present invention includes a lower cladding layer, a core portion, and an upper cladding layer, and at least one of the lower cladding layer, the core portion, and the upper cladding layer is (A) a carboxyl group-containing urethane compound. (B) a polymerizable unsaturated compound, (C) a curable resin composition containing two or more ring-opening polymerizable functional group-containing compounds in the molecule, and (D) a radiation polymerization initiator as essential components. Thus, the optical waveguide is formed using a dry film having a softening temperature of 0 ° C. to 80 ° C.

  In the optical waveguide according to the present invention, the difference in refractive index between the cladding layer and the core portion is preferably 0.1% or more.

  Since the composition of the present invention is composed of a specific composition, an optical waveguide having a low transmission loss composed of a lower cladding layer, a core portion, and an upper cladding layer can be obtained. Also, by making this optical waveguide curable resin composition into a dry film, all of the lower clad layer, the core portion, and the upper clad layer can be produced with a dry film without impairing mechanical properties. It can be formed easily with high accuracy in a short time.

  The curable resin composition for an optical waveguide of the present invention includes a carboxyl group-containing urethane compound (A) (hereinafter sometimes simply referred to as “compound (A)”), a polymerizable unsaturated compound (B) (hereinafter referred to as “compound unsaturated compound”). May be simply abbreviated as “compound (B)”), or two or more ring-opening polymerizable functional group-containing compounds (C) in the molecule (hereinafter simply abbreviated as “compound (C)”). ) And a radiation polymerization initiator (D) (hereinafter, sometimes simply abbreviated as “initiator (D)”) as essential components.

Carboxyl group-containing urethane compound (A):
Specifically, the compound (A) includes a polyhydroxycarboxylic acid compound (a) and a polyisocyanate compound (b) containing two or more hydroxyl groups in one molecule and one or more carboxyl groups in one molecule. The reaction product is preferred.

  Specific examples of the polyhydroxycarboxylic acid compound (a) include 2,2-dimethylolpropionic acid, 2,2-dimethylolacetic acid, 2,2-dimethylolpentanoic acid, or a triol compound and acid anhydride. Half ester compounds obtained by reaction of physical compounds, sulfonate diol compounds obtained by transesterifying sodium dimethylsulfoisophthalate and glycols under conditions of excess glycols, etc., and these compounds are You may use 1 type or in combination of 2 or more types.

  Specific examples of the polyisocyanate compound (b) include, for example, aliphatic diisocyanate compounds such as hexamethylene diisocyanate, trimethylene diisocyanate, 1,4-tetramethylene diisocyanate, pentamethylene diisocyanate, 1,2- Examples of alicyclic diisocyanate compounds such as propylene diisocyanate, 1,2-butylene diisocyanate, trimethylhexamethylene diisocyanate, dimer acid diisocyanate, lysine diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), methylcyclohexane-2,4- (or -2,6-) diisocyanate 1,3- (or 1,4-) di (isocyanatomethyl) cyclohexane, 1,4-cyclohexane diisocyanate, 1,3-cyclopentane diisocyanate, 1,2-cyclohexane diisocyanate, etc .; as aromatic diisocyanate compounds Is, for example, xylylene diisocyanate, metaxylylene diisocyanate, tetramethylxylylene diisocyanate, tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, 1,4-naphthalene diisocyanate, 4,4′- Toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, (m- or p-) phenylene diisocyanate, 4,4'-biphenylene diisocyanate, 3,3'-dimethyl -4,4'-biphenylene diisocyanate, bis (4-isocyanatophenyl) sulfone, isopropylidenebis (4-phenylisocyanate); Other polyisocyanates include, for example, triphenylmethane-4,4 ', 4 '' -Triisocyanate, 1,3,5-triisocyanatobenzene, 2,4,6-triisocyanatotoluene, 4,4′-dimethyldiphenylmethane-2,2 ′, 5,5′-tetraisocyanate, etc. Polyisocyanate compound having 3 or more isocyanate groups, ethylene glycol, propylene glycol, 1,4-butylene glycol, polyalkylene glycol, trimethylolpropane, hexanetriol and the like, the isocyanate groups are in an excessive amount. Quantity of poly Adducts obtained by reacting isocyanate compounds, burette type adducts such as hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate) And isocyanuric ring type adducts. These can be used alone or in combination of two or more.

  Among these compounds, aromatic diisocyanate compounds are particularly difficult to hydrolyze with respect to an alkali developer, and can form a photocured film having a high resistance to an alkaline developer or an etching solution. Since it is tough, it is preferable that the resist film that has been photocured in the resist pattern forming method is sufficiently adhered without being peeled off from the substrate by an external force such as an etchant, for example.

  In addition to the above, a polyol compound can be blended as necessary.

  The polyol compound adjusts the balance between hydrophilicity and hydrophobicity in the polyurethane compound by introducing a hydrophobic group that does not contain a carboxyl group in the molecule into the molecular main chain, and also uses a polyalkylene glycol (number average molecular weight). About 500 to 5000) itself imparts hydrophilicity, but this can soften the resist film, so that the film performance such as alkali developability and etching resistance can be improved.

  Specific examples of the polyol compound include (poly) methylene glycol, (poly) ethylene glycol, (poly) propylene glycol, 1,4-butanediol, 1,3-butanediol, and 2,3-butane. Diol, 1,2-butanediol, 3-methyl-1,2-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,4-pentanediol, 2,4-pentanediol, 2, 3-dimethyltrimethylene glycol, 3-methyl-4,3-pentanediol, 3-methyl-4,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,6-hexanediol 1,5-hexanediol, 1,4-hexanediol, 2,5-hexanediol, 1,4-cyclohexane dimethyl Nord, neopentyl glycol, pentaerythritol, trimethylolpropane, glycerol, and the like. These can be used alone or in combination of two or more.

  A compound (A) can be manufactured by the well-known method similar to a general polyurethane resin. That is, the carboxyl group-containing polyol compound (a), the polyisocyanate compound (b), and, if necessary, the mixture of the polyol compound and the hydroxyl group are the same as or in excess of the isocyanate group (for example, isocyanate group / hydroxyl group = about 1.1 A carboxyl group-containing isocyanate compound can be produced by subjecting an isocyanate group and a hydroxyl group to an addition reaction of a compound formulated so as to have a molar ratio of about -2.0 molar ratio, preferably about 1.2-1.9 molar ratio. .

  Before the reaction, the carboxyl group is blocked in advance by esterification with, for example, a lower alcohol such as methanol, ethanol, or propanol, and then the reaction is removed by heating to regenerate the carboxyl group. You can also.

  In the addition reaction between an isocyanate group and a hydroxyl group, for example, the temperature of the reaction system is usually 50 to 150 ° C. Moreover, it is good to use a urethanation reaction catalyst as needed. Examples of the urethanization reaction catalyst include organic tin compounds such as tin octylate and dibutyltin dilaurate.

  Moreover, a compound (A) can contain a polymerizable unsaturated group as needed. Specifically, for example, a part of the carboxyl group contained in the compound (A) is converted into a reactive group such as an epoxy group or an isocyanate group that reacts with the carboxyl group and a radical such as an acryloyl group, a methacryloyl group, or a vinyl group. An unsaturated group can be introduced by reacting with an unsaturated compound containing a polymerizable unsaturated group. Examples of such unsaturated compounds include epoxy group-containing unsaturated compounds such as glycidyl (meth) acrylate and isocyanate ethyl (meth) acrylate.

  The number average molecular weight of the compound (A) is particularly preferably in the range of about 1000 to 200000, particularly about 2000 to 80000. When the number average molecular weight is less than about 1000, the workability of the dry film is reduced. On the other hand, when the number average molecular weight exceeds 200,000, the dry film is generally heated and pasted when the dry film is pasted to the substrate. Since there is little viscosity reduction by this heating, since workability | operativity of sticking falls or a bubble is produced after sticking, performance worsens. The compound (A) preferably has a softening temperature of 0 to 120 ° C, particularly 20 to 100 ° C. When the softening temperature is less than 0 ° C., a dry film cannot be formed, or the film becomes sticky, resulting in inconvenience when laminated on a substrate. On the other hand, when the temperature exceeds 120 ° C., the film becomes hard or brittle, and transferability is lowered.

  In this specification, the softening temperature (TMA) was measured by the thermal deformation behavior of a 1 mm thick sheet using a DuPont Thermomechanical Analyzer. That is, a quartz needle was placed on the sheet, a load of 49 g was applied, the temperature was raised at 5 ° C./min, and the temperature at which the needle entered 0.635 mm was defined as TMA.

  The carboxyl group content of the compound (A) is preferably in the range of 30 to 180, particularly 40 to 120 as the acid value (mg / g KOH). When the acid value of the compound (A) is less than 30, the developability with an alkaline developer is lowered and it is difficult to form an optical waveguide with good performance. On the other hand, if it exceeds 180, the solubility in an alkali developer becomes too high, and it is difficult to form a sharp optical waveguide.

Polymerizable unsaturated compound (B):
Examples of the compound (B) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, 2 -Ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, n-octyl (meth) acrylate, lauryl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, 2-ethylhexyl carbitol (meth) acrylate, isobornyl Alkyl or cycloalkyl ester monomers of (meth) acrylic acid such as (meth) acrylate; methoxybutyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxybutyl (meth) Alkoxyalkyl ester monomers of (meth) acrylic acid such as acrylate, trimethylolpropane tripropoxy (meth) acrylate; aromatic vinyl monomers such as styrene, α-methylstyrene, vinyltoluene; (meth) acrylic acid, maleic acid, etc. α, β-ethylenically unsaturated carboxylic acid monomers; acrylic phosphate monomers such as dimethyl phosphate ethyl acrylate and diethyl phosphate ethyl acrylate; glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, glycidyl ether, etc. Epoxy group-containing unsaturated monomer; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyla (meth Hydroxyl-containing unsaturation such as acrylate, 3-hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, (poly) alkylene glycol monoacrylate, and adducts of these monomers with lactones (for example, ε-caprolactone, etc.) Monomers; Esters of aromatic alcohols such as benzyl (meth) acrylate and (meth) acrylic acid; Glycidyl (meth) acrylate or hydroxyalkyl esters of (meth) acrylic acid and capric acid, lauric acid, linoleic acid, oleic acid, etc. Of adducts with monocarboxylic acid compounds, adducts of (meth) acrylic acid with monoepoxy compounds such as “Cardura E10” (manufactured by Shell Chemical); ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, hexyl vinyl ether Chain alkyl vinyl ethers such as tellurium and octyl vinyl ether; cycloalkyl vinyl ethers such as cyclopentyl vinyl ether, cyclohexyl vinyl ether and 1,4-cyclohexanedimethanol divinyl ether; allyl ethers such as allyl glycidyl ether and allyl ethyl ether; ) Fluorine-containing unsaturated monomers such as acrylate, perfluoroisononylethyl (meth) acrylate, perfluorooctylethyl (meth) acrylate; (meth) acryloylmorpholine, 2-vinylpyridine, 1-vinyl-2-pyrrolidone, vinylcaprolactam , Dimethyl (meth) acrylamide, N, N-dimethylethyl (meth) acrylate, diacetone acrylamide, etc. -; Ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetra or higher poly (4-16) ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate Polyfunctional alcohol-modified polyfunctional monomers such as trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ethylene glycol diitaconate, ethylene glycol dimaleate; other hydroquinone di (meth) acrylate, resorcinol Di (meth) acrylate, pyrogallol (meth) acrylate; unsaturated group-containing resin (such as an adduct obtained by adding (meth) acrylic acid to a polyester polyol). Cuss 8100, 8030, etc. (trade name, manufactured by Toagosei Co., Ltd.). Moreover, said unsaturated compound can be used 1 type or in combination of 2 or more types.

Two or more ring-opening polymerizable functional group-containing compounds (C) in the molecule:
The compound (C) is preferably a compound having two or more cyclic ethers in the molecule. Examples of such compounds include oxirane compounds, oxetane compounds, and oxolane compounds. Specifically, for example, as oxirane compounds, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4- Epoxy) cyclohexane-meta-dioxane, bis (3,4-epoxycyclohexylmethyl) adipate, vinylcyclohexylene oxide, 4-vinylepoxycyclohexane, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 3,4- Epoxy-6-methylcyclohexyl-3 ′, 4′-epoxy-6′-methylcyclohexanecarboxylate, methylenebis (3,4-epoxycyclohexane), dicyclopentadiene diepoxide, di (3,4-epoxycyclo) of ethylene glycol F Silmethyl) ether, ethylenebis (3,4-epoxycyclohexanecarboxylate), epoxidized tetrabenzyl alcohol, lactone modified 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, lactone modified epoxidized tetrahydrobenzyl Alcohol, cyclohexene oxide, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol AD diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, brominated bisphenol S diglycidyl Ether, epoxy novolac resin, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ethers Polyglycidyl ethers of polyether polyols obtained by adding one or more alkylene oxides to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin; diglycidyl aliphatic long-chain dibasic acids Esters; monoglycidyl ethers of higher aliphatic alcohols; phenol, cresol, butylphenol or alkylene oxide added to these Monoglycidyl ethers of polyether alcohols obtained Te; glycidyl esters of higher fatty acids; epoxidized soybean oil, butyl epoxy stearate, epoxy stearic octyl, and the like epoxidized linseed oil. As the oxetane compound, 3,7-bis (3-oxetanyl) -5-oxa-nonane, 3,3 ′-(1,3- (2-methylenyl) propanediylbis (oxymethylene)) bis- (3-ethyl) Oxetane), 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, 1,2-bis [(3-ethyl-3-oxetanylmethoxy) methyl] ethane, 1,3-bis [( 3-ethyl-3-oxetanylmethoxy) methyl] propane, ethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenyl bis (3-ethyl-3-oxetanylmethyl) ether, triethylene glycol bis (3 -Ethyl-3-oxetanylmethyl) ether, tetraethylene glycol bis (3-ethyl-3-oxeta) Nylmethyl) ether, tricyclodecanediyldimethylene (3-ethyl-3-oxetanylmethyl) ether, trimethylolpropane tris (3-ethyl-3-oxetanylmethyl) ether, 1,4-bis (3-ethyl-3- Oxetanylmethoxy) butane, 1,6-bis (3-ethyl-3-oxetanylmethoxy) hexane, pentaerythritol tris (3-ethyl-3-oxetanylmethyl) ether, pentaerythritol tetrakis (3-ethyl-3-oxetanylmethyl) An ether etc. can be illustrated and these can be used individually by 1 type or in combination of 2 or more types.

  These commercially available products include Epolite 40E, 100E, 70P, 1500NP, 100MF, 4000, 3002 (manufactured by Kyoeisha Chemical Co., Ltd.), Celoxide 2021, 2081, GT301, GT401, Eporide CDM, PB3600, Epofriend A1005, A1010, A1020. (Above, manufactured by Daicel Chemical Industries), Denacol 611, 612, 512, 521, 411, 421, 313, 321 (above, manufactured by Nagase Kasei), Epicoat EP-828EL (made by Japan Epoxy Resin Co., Ltd., trade name), EXA- 750 (Dainippon Ink Co., Ltd., trade name).

Radiation polymerization initiator (D):
A conventionally well-known thing can be used as an initiator (D). Examples thereof include aromatic carbonyl compounds such as benzophenone, benzoin methyl ether, benzoin isopropyl ether, benzylxanthone, thioxanthone and anthraquinone; acetophenone, propiophenone, α-hydroxyisobutylphenone, α, α'-dichloro-4 Acetophenones such as phenoxyacetophenone, 1-hydroxy-1-cyclohexylacetophenone, diacetylacetophenone, acetophenone; benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, t-butyl hydroperoxide, di-t- Organic peroxides such as butyldiperoxyisophthalate, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone; diphenyliodo Diphenylhalonium salts such as romide and diphenyliodonium chloride; organic halides such as carbon tetrabromide, chloroform and iodoform; 3-phenyl-5-isoxazolone, 2,4,6-tris (trichloromethyl) -1,3 Heterocyclic and polycyclic compounds such as 2,5-triazinebenzanthrone; 2,2′-azo (2,4-dimethylvaleronitrile), 2,2-azobisisobutyronitrile, 1,1′-azobis Azo compounds such as (cyclohexane-1-carbonitrile) and 2,2′-azobis (2-methylbutyronitrile); iron-allene complexes (see European Patent No. 152377); titanocene compounds (Japanese Patent Laid-Open No. 63-221110) Bisimidazole compound; N-aryl glycidyl compound; acridine Compound; a combination of aromatic ketone / aromatic amine; peroxy ketal (see Japanese Patent Laid-Open No. 6-321895) and the like. Among the above-mentioned photo radical polymerization initiators, di-t-butyldiperoxyisophthalate, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone, iron-allene complex and titanocene compound are This is preferably used because of its high activity for crosslinking or polymerization.

  Further, as trade names, for example, Irgacure 651 (Ciba Geigy, trade name, acetophenone photoradical polymerization initiator), Irgacure 184 (Ciba Geigy, trade name, acetophenone photoradical polymerization initiator), Irgacure 1850 ( Ciba Geigy, trade name, acetophenone photoradical polymerization initiator), Irgacure 907 (Ciba Geigy, trade name, aminoalkylphenone photoradical polymerization initiator), Irgacure 369 (Ciba Geigy, trade name, aminoalkylphenone) -Based photoradical polymerization initiator), Lucillin TPO (manufactured by BASF, trade name, 2,4,6-trimethylbenzoyldiphenylphosphine oxide), Kayacure DETXS (manufactured by Nippon Kayaku Co., Ltd., trade name), Irgacure 784 ( Ciba Geigy Manufactured, trade name, titanium complex compound), UVI-6950, UVI-6970, UVI-6974, UVI-6990 (manufactured by Union Carbide), Adekaoptomer SP-150, SP-151, SP-170, SP -171 (above, manufactured by Asahi Denka Kogyo Co., Ltd.), Irgacure 261 (above, manufactured by Ciba Geigy), CI-2481, CI-2624, CI-2638, CI-2039 (above, manufactured by Nippon Soda Co., Ltd.), CD-1010, CD-1011, CD-1012 (manufactured by Sartomer), DTS-102, DTS-103, NAT-103, NDS-103, TPS-102, TPS-103, MDS-103, MPI-103 , BBI-101, BBI-102, BBI-103 (above, manufactured by Midori Chemical Co., Ltd.), Degacu re K126 (manufactured by Degussa). These initiators (D) can be used singly or in combination of two or more.

  Moreover, said photoinitiator and photoinitiator adjuvant (sensitizer) can be used together as needed. Examples of the photopolymerization initiation assistant include 2-dimethylaminoethyl benzoate, N, N′-dimethylaminoethyl methacrylate, p-dimethylaminobenzoic acid isoamyl ester, p-dimethylaminobenzoic acid ethyl ester, and the like.

  In the present invention, the compounding ratio of the compound (A), the compound (B), the compound (C), and the initiator (D) is as follows when the total measurement (solid content conversion) of these components is 100% by weight. is there.

  Compound (A): 10% to 90% by weight, preferably 30% to 70% by weight.

  When the amount of the compound (A) is less than 10% by weight, the number of carboxyl groups contained in the compound (A) decreases in the composition, so that developability with an alkaline developer is lowered and a high-performance optical waveguide cannot be formed. . In addition, film formation becomes difficult. On the other hand, if it exceeds 90% by weight, the ratio of the compound (A) contained in the composition is too high. For example, if the ratio of the compound (B) is low, the photocurability is lost and the optical waveguide core can be formed. When the ratio of the compound (C) decreases or the ratio of the compound (C) decreases, the number of ring-opening polymerizable functional groups that crosslink with the carboxyl group of the compound (A) decreases, and the number of crosslinks with the compound (A) decreases, resulting in formation. The reliability of the optical waveguide is poor.

  Compound (B): 1% to 60% by weight, preferably 5% to 30% by weight.

  When the compound (B) is less than 1% by weight, the concentration of unsaturated groups contained in the composition is lowered, the photocurability is lost, and the optical waveguide core cannot be formed. On the other hand, when it exceeds 60% by weight, the proportion of the compound (B) in the composition increases, and the proportion of the compound (A) or the compound (C) decreases. For example, when the ratio of the compound (A) is small, the acid value of the entire composition is lowered, developability by alkali development is lowered, and an optical waveguide with good performance cannot be formed. On the other hand, when the ratio of the compound (C) is reduced, the number of ring-opening polymerizable functional groups that crosslink with the carboxyl group of the compound (A) is reduced, and the number of crosslinks with the compound (A) is reduced, resulting in the light guide formed. The reliability of the waveguide is poor.

  Compound (C): 1% to 60% by weight, preferably 10% to 40% by weight.

  When the amount of the compound (C) is less than 1% by weight, the number of ring-opening polymerizable functional groups that crosslink with the carboxyl group of the compound (A) decreases, and the number of crosslinks with the compound (A) decreases. The reliability of the waveguide is poor. On the other hand, if it exceeds 60% by weight, the proportion of the compound (C) in the composition increases, and the proportion of the compound (A) or the compound (B) decreases. For example, when the ratio of the compound (A) is small, the acid value of the entire composition is lowered, developability by alkali development is lowered, and an optical waveguide with good performance cannot be formed. Or when the ratio of a compound (B) is made small, the number of unsaturated groups contained in a composition will reduce, photocurability will be lost, and optical waveguide core formation will become impossible.

  Initiator (D): 0.01% to 15% by weight, preferably 0.1% to 7% by weight.

  When the compound (D) is less than 0.01% by weight, curing does not proceed sufficiently even when irradiated with radiation, and as a result, a good optical waveguide core cannot be formed, adversely affecting the transmission characteristics of the optical waveguide. . On the other hand, if the amount exceeds 15% by weight, the radiation does not reach the deep part of the composition, the difference in the degree of cure occurs between the surface and the deep part of the composition film, and a good optical waveguide core cannot be formed. In addition, the unreacted compound (D) gradually reacts over a long period of time, resulting in an adverse effect on the long-term stability of the optical waveguide.

  The curable resin composition for an optical waveguide of the present invention is obtained by dissolving or dispersing the components of the compound (A), the compound (B), the compound (C) and the initiator (D) in an organic solvent. Can be used as a thing. Examples of the organic solvent include conventionally known organic solvents such as ketones, esters, ethers, cellosolves, aromatic hydrocarbons, alcohols, and halogenated hydrocarbons.

  Further, the curable resin composition for an optical waveguide of the present invention comprises a neutralized product obtained by neutralizing the above compound (A) with a basic compound, a compound (B), a compound (C), and an initiator (D). It can be dispersed in water and used as an aqueous resin composition.

  Examples of the basic compound include monoethanolamine, diethanolamine, triethylamine, diethylamine, dimethylaminoethanol, cyclohexylamine, ammonia, caustic soda, caustic potash, and the like. The amount of the neutralizing agent used is generally 0.2 to 1.0 equivalent, and particularly preferably 0.3 to 0.8 equivalent, per equivalent of the carboxyl group contained in the compound (A).

  The curable dry film for forming an optical waveguide of the present invention has a softening temperature of 0 to 80 ° C., particularly 10 to 80 ° C., which is formed by the above-described curable resin composition for an optical waveguide.

  When the softening temperature of the dry film is less than 0 ° C., the dry film is generally applied by heating when the dry film is applied to the base material, but this heating softens the dry film and causes stickiness. , Sticking work becomes extremely difficult, or bubbles are generated after sticking. On the other hand, when the temperature exceeds 80 ° C., the sticking itself cannot be performed, and the transfer of the dry film becomes impossible.

  The curable dry film for forming an optical waveguide of the present invention is obtained by coating the above-described curable resin composition for an optical waveguide with an organic solvent-based resin composition or an aqueous resin composition on a supporting substrate, forming a wet film by printing, It can be formed by drying at a temperature that does not cure. The dry film formed on the obtained support substrate can be used as a material for an optical waveguide by peeling the dry film from the support substrate and then using the separated dry film. Moreover, it is also possible to peel off the support substrate which became unnecessary after using as a material for optical waveguides, without peeling a dry film from a support base material.

  As the supporting substrate, for example, any film such as polyethylene terephthalate film, aramid, kapton, polymethylpentene, polyethylene, polypropylene, etc. can be used. In particular, it is cost and photosensitive dry film to use a polyethylene terephthalate film. It can be said that it is optimal for obtaining good characteristics as. The thickness of the supporting substrate is usually 1 to 100 μm, particularly preferably 10 to 40 μm.

  Moreover, as a method of coating or printing the above-described resin composition on these supporting substrates, for example, a roller method, a spray method, a silk screen method, or the like can be performed. The film thickness of the dry film may be appropriately selected according to the optical waveguide to be produced, but is usually in the range of 1 μm to 10 mm, particularly 5 μm to 5 mm.

  The optical waveguide of the present invention includes a lower clad layer, a core portion, and an upper clad layer, and at least one of the lower clad layer, the core portion, and the upper clad layer is a cured product of the above-described curable dry film for forming an optical waveguide. Formed from.

  In the optical waveguide of the present invention, when used in at least a part of each part finally obtained (upper / lower clad part and core part), the relationship of the refractive index of each part should satisfy the conditions required for the optical waveguide. In addition, by appropriately selecting the type and blending amount of each component, it is possible to obtain a curable dry film for forming an optical waveguide from which a cured film having a different refractive index can be obtained.

  In the present invention, the curable dry film for forming an optical waveguide of the present invention is used only for the core portion, and other clad portions are produced with a conventional radiation curable dry film solution, or the lower clad portion and the core portion are formed. An optical waveguide can be produced using the curable dry film for forming an optical waveguide of the present invention, and further using the curable dry film for forming an optical waveguide of the present invention for all the layers.

Hereinafter, an example of an embodiment relating to an optical waveguide using the dry film of the present invention and a method for manufacturing the optical waveguide will be specifically described with reference to the drawings as appropriate.
(Basic optical waveguide configuration)
FIG. 1 is a cross-sectional view showing a basic structure of an optical waveguide configured by applying a curable dry film for forming an optical waveguide. As shown in FIG. 1, an optical waveguide 10 includes a substrate 12, a lower cladding layer 13 formed on the surface of the substrate 12, and a core having a specific width formed on the lower cladding layer 13. A portion 15 and an upper clad layer 17 formed by being laminated on the lower clad layer 13 including the core portion 15 are configured. The core portion 15 is covered with the lower clad layer 13 and the upper clad layer 17 so as to reduce the waveguide loss, and is buried as a whole.
(Thickness and width)
In the optical waveguide configured as described above, the thicknesses of the lower cladding layer, the upper cladding layer, and the core portion are not particularly limited. For example, the thickness of the lower cladding layer is 1 to 200 μm, and the core portion Preferably, the thickness of the upper cladding layer is set to a value within the range of 1 to 200 μm. Further, the width of the core portion is not particularly limited, but for example, a value in the range of 1 to 200 μm is preferable.
(Refractive index)
Further, it is necessary to make the refractive index of the core portion larger than any of the refractive indexes of the lower and upper clad layers. Accordingly, the refractive index of the core portion is set to a value in the range of 1.420 to 1.650 for light having a wavelength of 400 to 1,600 nm, and the refractive indexes of the lower cladding layer and the upper cladding layer are set to 1. A value in the range of 400 to 1.648 is preferable. Further, the difference in refractive index between the core portion and the cladding layer is preferably 0.1% or more, and in particular, the refractive index of the core portion should be at least 0.1% larger than the refractive index of the cladding layer. preferable.

2 is a cross-sectional view of the cut surface of FIG. 1 as viewed from the front. The optical waveguide 10 is formed through a process as shown in FIG. That is, the curable dry film for forming an optical waveguide for forming any one or all of the lower clad layer 13, the core portion 15 and the upper clad layer 17 is sequentially transferred onto a substrate and then cured by radiation. It is preferable to form by this. In the following formation examples, description will be made on the assumption that the lower clad layer and the core portion are made of a dry film, and the upper clad layer is made of a curable dry film for forming an optical waveguide.
(Preparation of substrate)
First, a substrate 12 having a flat surface is prepared. The type of the substrate 12 is not particularly limited. For example, a silicon substrate or a glass substrate can be used.
(Process for forming the lower cladding layer)
In this step, the lower clad layer 13 is formed on the surface of the prepared substrate 12. Specifically, as shown in FIG. 3A, while removing the cover film on the surface of the substrate 12 so that the base film is on top, the normal pressure hot roll pressure bonding method, the vacuum hot roll pressure bonding method, the vacuum The dry film is transferred onto the substrate while applying appropriate heat and pressure using a pressure bonding method such as a hot press pressure bonding method. The lower clad layer 13 can be formed by curing the lower layer thin film by irradiating with radiation. In the step of forming the lower clad layer 13, it is preferable to irradiate the entire surface of the thin film and harden the whole.

Also, the radiation dose when forming the lower cladding layer is not particularly limited, but radiation with a wavelength of 200 to 440 nm and an illuminance of 1 to 500 mW / cm ² is applied with a dose of 10 to 5,000 mJ. It is preferable to perform exposure by irradiating so as to be / cm ² . Here, visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays, γ-rays, and the like can be used as the type of radiation to be irradiated, and ultraviolet light is particularly preferable. For example, a high pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp, or an excimer lamp is preferably used as a radiation (ultraviolet) irradiation device. Further, it is preferable to further perform a heat treatment (hereinafter referred to as “post-bake”) so that the entire surface of the coating film is sufficiently cured after the exposure. This heating condition varies depending on the blending composition of the radiation curable resin dry film, the kind of additive, and the like, but is usually 30 to 400 ° C., preferably 50 to 300 ° C., for example, for 5 minutes to 72 hours. It ’s fine. Note that the radiation dose, type, and radiation (ultraviolet) irradiation device in the lower clad layer forming step are also applicable to the core portion forming step and the upper clad layer forming step, which will be described later.

  Next, the radiation curable resin dry film for forming the core portion is subjected to normal pressure while removing the cover film so that the base film is on the surface of the lower clad layer 13 in the same manner as the method for forming the lower clad layer. The dry film is transferred onto the substrate while applying appropriate heat and pressure using a pressure bonding method such as a heat roll pressure bonding method, a vacuum heat roll pressure bonding method, or a vacuum heat press pressure bonding method (FIG. 3B). Then, the core portion forming layer is cured by irradiating with radiation so that the core portion is formed, then the uncured portion is removed under the developer and conditions described below, and the core is formed on the surface of the lower clad layer 13. The part 15 can be formed.

  In order to easily obtain the stability of the pattern shape after development (developing resistance against developer) at the stage where the core portion is cured into a pattern, or to further improve the stability (developing resistance against developer) In order to achieve this, heat treatment may be performed on the resin layer for the core part or on both the lower clad resin layer and the core layer resin layer. The heat treatment can be performed, for example, using a hot plate or the like under a condition that a temperature of 60 to 100 ° C., preferably 65 to 85 ° C. is maintained for 1 to 10 minutes, preferably 1 to 3 minutes. By adding this heat treatment, for example, using a developer of an organic base aqueous solution such as a diethanolamine aqueous solution, a core shape having a high contrast with respect to a portion to be dissolved and removed at the time of development can be obtained with higher accuracy and shape stability. It becomes possible to form. Therefore, by performing this heat treatment, the selection range for the developer can be expanded, and it is possible to select a strong developer that enables faster processing and a developer that does not substantially contain metal ions. It becomes. For example, since metal ions such as sodium ions affect the semiconductor substrate, when forming an optical waveguide on the semiconductor substrate, a developer such as an organic base aqueous solution that does not contain metal ions such as sodium ions is preferable. By performing the above heat treatment, it is possible to perform development processing with higher accuracy in such a metal ion-free state.

  Next, after the core portion 15 is formed, a dry film for forming the upper clad layer 17 is transferred onto the core portion 15 and the lower clad layer 13 as shown in FIG. The upper clad layer 17 is formed by pre-baking. Thereafter, the optical waveguide of the present invention can be manufactured by irradiating radiation from the entire surface of the upper clad layer 17.

  Developers include organic solvents or sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine N-methylpyrrolidone, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, choline, pyrrole, piperidine, 1,8-diazabicyclo [5.4.0] -7-undecene, 1, An aqueous alkali solution composed of alkalis such as 5-diazabicyclo [4.3.0] -5-nonane can be used. Moreover, when using aqueous alkali solution, it is preferable to make the density | concentration into the value within the range of 0.05 to 25 weight% normally, Preferably it is 0.1 to 3.0 weight%. In addition, it is also preferable to add an appropriate amount of a water-soluble organic solvent such as methanol or ethanol, a surfactant or the like to such an alkaline aqueous solution and use it as a developer.

  The developing time is usually 30 to 600 seconds, and a known method such as a liquid piling method, a dipping method, or a shower developing method can be adopted as the developing method. When an organic solvent is used as the developer, it is air-dried as it is, and when an alkaline aqueous solution is used, it is washed with running water, for example, for 30 to 90 seconds, and then air-dried with compressed air, compressed nitrogen, etc. By removing the moisture, a patterned film is formed. Next, in order to further cure the patterning portion, a post-baking process is performed, for example, at a temperature of 30 to 400 ° C. for 5 to 600 minutes by a heating device such as a hot plate or an oven, and a cured core portion is formed.

  In the present invention, in particular, the curable resin composition for forming an optical waveguide that has flowed by heating by using the curable dry film for forming an optical waveguide of the present invention as the cladding layer of the thin film for the upper layer is a depression in the convex portion of the core portion. Since the clad layer is formed by flowing and filling, the gap is formed without generating a gap between the core layer and the clad layer.

  Next, the upper thin layer 17 can be formed as shown in FIG. 1 by irradiating and curing the upper layer thin film.

  Moreover, it is preferable that the upper clad layer obtained by radiation irradiation is further post-baked as described above, if necessary. By post-baking, an upper cladding layer having excellent hardness and heat resistance can be obtained.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Preparation Example of Curable Resin Composition for Optical Waveguide Synthesis Example of Carboxyl Group-Containing Urethane Compound (A-1) An appropriate amount of methyl ethyl ketone solvent is put in a flask equipped with a reflux, and two hydroxyl groups in one molecule are contained therein. And 39.4 g of dimethylolbutanoic acid having one carboxyl group, 7.6 g of 1,6-hexanediol having two hydroxyl groups in one molecule, neopentyl having two hydroxyl groups in one molecule 6.7 g of glycol, 46.3 g of toluene diisocyanate having two isocyanate groups in the molecule, and 500 ppm of dibutyltin dilaurate as a reaction catalyst were added, and the temperature was raised to 75 ° C. while stirring. After maintaining the temperature at 75 ° C., the reaction was carried out with stirring for 12 hours while maintaining this temperature to obtain carboxyl group-containing urethane compound A-1.

Synthesis Example of Carboxyl Group-Containing Urethane Compound (A-2) An appropriate amount of methyl ethyl ketone solvent is placed in a flask equipped with a reflux condenser, and dimethylolbutane having two hydroxyl groups and one carboxyl group in one molecule therein. 35.7 g of acid, 13.8 g of 1,6-hexanediol having two hydroxyl groups in one molecule, 50.5 g of trimethylhexamethylene diisocyanate having two isocyanate groups in the molecule, dibutyltin as a reaction catalyst 500 ppm of dilaurate was added, and the temperature was raised to 75 ° C. while stirring. After raising the temperature at 75 ° C., the reaction was carried out with stirring for 12 hours while maintaining this temperature to obtain carboxyl group-containing urethane compound A-2.

Synthesis example (for comparative example) of carboxyl group-containing urethane compound (A-3)
An appropriate amount of methyl ethyl ketone solvent is placed in a flask equipped with a refluxer, and 39.8 g of dimethylolbutanoic acid having two hydroxyl groups and one carboxyl group in one molecule is contained therein. 13.5 g of neopentyl glycol having a hydroxyl group, 46.7 g of trimethylhexamethylene diisocyanate having two isocyanate groups in the molecule, 500 ppm of dibutyltin dilaurate as a reaction catalyst were added, and the temperature was raised to 75 ° C. while stirring. . After raising the temperature at 75 ° C., the reaction was carried out with stirring for 12 hours while maintaining this temperature to obtain a carboxyl group-containing urethane compound A-3.

Synthesis example (comparative example) of radically polymerizable compound (A-4)
After substituting the flask equipped with a dry ice / methanol reflux with nitrogen, 0.5 g of 2,2-azobisdimethylvaleronitrile as a polymerization initiator and 54.3 g of ethyl lactate as an organic solvent were charged. Stir until dissolved. Subsequently, 4.5 g of methacrylic acid, 9.0 g of dicyclopentanyl methacrylate, 20.4 g of methyl methacrylate, and 11.3 g of n-butyl acrylate were charged, and then gently stirring was started. Thereafter, the temperature of the solution was raised to 80 ° C., and polymerization was carried out at this temperature for 4 hours. Thereafter, the reaction product was dropped into a large amount of hexane to solidify the reaction product. Further, it was redissolved in tetrahydrofuran having the same weight as this coagulated product and coagulated again with a large amount of hexane. After this re-dissolution-coagulation operation was performed 3 times in total, the obtained coagulated product was vacuum-dried at 40 ° C. for 48 hours to obtain radical polymerizable compound A-4.

Synthesis example (for comparative example) of ethylenically unsaturated group-containing carboxylic acid resin (A-5)
175 g of phenol novolak resin (manufactured by Nippon Kayaku Co., Ltd., LRE-305), 317.7 g of polyethylene glycol diacrylate (manufactured by Nippon Kayaku Co., Ltd., KAYARAD PEG400DA), 50.4 g of acrylic acid, 40 of dimethylo-propionic acid .2 g and 0.5 g of P-methoxyphenol are charged and dissolved and mixed at 80.degree. C., and then 1.6 g of triphenylphosphine is added and reacted at 95.degree. C. for about 32 hours. After the reaction was completed, 50 g of succinic anhydride was charged and reacted at 90 ° C. for about 10 hours. After the anhydride group in the reaction solution disappeared, the reaction was terminated and polyethylene glycol dilute as a diluent was used. A product A-7 containing 50% by weight of acrylate and having an acid value of 88 excluding diluent was obtained.

Preparation of Curable Resin Composition Z-1 for Optical Waveguide Aronix 8100 (Toagosei Co., Ltd.) as compound (B) with respect to 61.5 parts by weight of the above-mentioned carboxyl group-containing urethane compound A-1 as compound (A). Manufactured, trade name) 12.3 parts by weight, trimethylolpropane triacrylate 6.1 parts by weight, and compound (C) as Epicoat EP-828EL (trade name, manufactured by Japan Epoxy Resin Co., Ltd.) 19.5 parts by weight, compound ( As D), 0.6 part by weight of Irgcure 907 (manufactured by Ciba Specialty Chemicals) was added and mixed in a methyl ethyl ketone solvent to obtain a uniform solution of composition Z-1.

Preparation of Curable Resin Composition Z-2 for Optical Waveguide Trimethylolpropane triacrylate as compound (B) with respect to 59.4 parts by weight of the above-mentioned carboxyl group-containing urethane compound A-2 which is compound (A). 8 parts by weight, EXA-750 (trade name) manufactured by Dainippon Ink Co., Ltd. as compound (C) 21.6 parts by weight, Irgcure 907 (manufactured by Ciba Specialty Chemicals) 0.6 part by weight as compound (D), N 0.6 parts by weight of-(trifluoromethylsulfonyloxy) -1,8-naphthalenedicarboximide was added and mixed in a methyl ethyl ketone solvent to obtain a uniform solution.

Preparation of curable resin composition Z-3 for optical waveguide (for Comparative Example 1)
61.3 parts by weight of the above-mentioned carboxyl group-containing urethane compound A-3, which is the compound (A), 12.3 parts by weight of Aronix 8100 (trade name, manufactured by Toagosei Co., Ltd.) as a compound (B), trimethylol 6.1 parts by weight of propanetriacrylate, 19.5 parts by weight of Epicote EP-828EL (trade name, manufactured by Japan Epoxy Resin Co., Ltd.) as the compound (C), and Irgcure 907 (manufactured by Ciba Specialty Chemicals, Inc.) as the compound (D) Name) 0.6 part by weight was added and mixed in a methyl ethyl ketone solvent to obtain a uniform solution.

Preparation of curable resin composition Z-4 for optical waveguide (for Comparative Example 2)
Aronix 8100 (trade name, manufactured by Toagosei Co., Ltd.) 10.0 parts by weight as a compound (B), 6.5 parts by weight of trimethylolpropane triacrylate with respect to 32.0 parts by weight of the radical polymerizable compound A-4 described above. As a compound (D), 3.0 parts by weight of Irgcure 907 (trade name, manufactured by Ciba Specialty Chemicals) and 48.5 parts by weight of ethyl lactate were added and mixed to obtain a uniform solution.

Preparation of curable resin composition Z-5 for optical waveguide (for Comparative Example 3)
It is a photopolymerization initiator and 29 parts by weight of KAYARAD R-604 (trade name, manufactured by Nippon Kayaku Co., Ltd.), which is a polymerizable compound, with respect to 68 parts by weight of the above-described ethylenically unsaturated group-containing carboxylic acid resin A-5. 3.0 parts by weight of Irgcure 907 (trade name, manufactured by Ciba Specialty Chemicals) was added and mixed to obtain a uniform solution.

  The above optical waveguide resin compositions are summarized in Table 1.

Example 1
Formation of Optical Waveguide Formation of Lower Clad Layer Optical waveguide curable resin composition Z-2 was applied onto the surface of a silicon substrate by spin coating and dried at 80 ° C. for 30 minutes. Then, after irradiating with ultraviolet rays having a wavelength of 365 nm and an illuminance of 200 mW / cm ² for 5 seconds, thermosetting was performed at 150 ° C. for 30 minutes to obtain a lower cladding layer having a thickness of 40 μm.

Formation of core part (1)
Next, the curable resin composition for optical waveguide Z-1 was applied on the lower clad layer by a spin coating method and dried at 80 ° C. for 30 minutes. Next, radiation curing was performed by irradiating ultraviolet rays having a wavelength of 365 nm and an illuminance of 10 mW / cm ² for 100 seconds through a photomask having a line pattern having a width of 30 μm. Next, the substrate having the resin composition layer irradiated with radiation was immersed in a developer composed of a 1.8% tetramethylammonium hydroxide aqueous solution (TMAH) to dissolve the unexposed portion of the resin composition, and then 150 Post-baking was performed at 30 ° C. for 30 minutes. In this way, a core portion having a line pattern having a width of 30 μm was formed.

Formation of core part (2)
Next, the curable resin composition for optical waveguide Z-1 was applied on the lower clad layer by a spin coating method and dried at 80 ° C. for 30 minutes. Next, radiation curing was performed by irradiating ultraviolet rays having a wavelength of 365 nm and an illuminance of 10 mW / cm ² for 100 seconds through a photomask having a line pattern of 30 μm width. The substrate subjected to the ultraviolet irradiation treatment was subjected to a heat treatment (called post-cure) for holding a temperature of 65 ° C. for 1 minute and 30 seconds using a hot plate. Next, the substrate having the resin composition layer irradiated with radiation was dipped in a developer composed of a 1% by weight diethanolamine aqueous solution (temperature 35 ° C.) to dissolve unexposed portions of the resin composition, and then 150 ° C. and 30 ° C. Post-baked under conditions of minutes. In this way, a core portion having a line pattern having a width of 30 μm was formed.

Formation of upper clad layer The lower clad layer having the core portion formed by the methods (1) and (2) described above is used individually, and the optical waveguide curability is formed on the upper surface of the lower clad layer provided with the core portion. Resin composition Z-2 was applied by spin coating and dried at 80 ° C. for 30 minutes. Thereafter, the resin composition layer was irradiated with ultraviolet rays having a wavelength of 365 nm and an illuminance of 200 mW / cm ² for 5 seconds, and further post-baked at 150 ° C. for 30 minutes to form an upper cladding layer having a thickness of 40 μm.

  A conceptual cross-sectional view of the optical waveguide described above is as shown in FIG.

Comparative Examples 1-3
An optical waveguide was formed by the same method as in Example 1 except that the lower clad layer, core portion, and upper clad layer were used in the same manner as in Example 1 except that the compositions shown in Table 2 were used instead of the compositions described in Example 1.

  The results are shown in Table 2.

  In Table 2, the transmission loss was evaluated by the following method.

  Light having a wavelength of 850 nm was incident from one end to the optical waveguides of Example 1 and Comparative Examples 1 to 3. Then, by measuring the amount of light emitted from the other end, the loss per unit length (hereinafter referred to as “transmission loss”) was determined by the cutback method.

  Example 1 was an optical waveguide having a transmission loss as low as 0.2 dB / cm. On the other hand, in Comparative Example 1, the unexposed portion was not completely dissolved during the development process for forming the core portion, and the exposed portion was also swollen by TMAH and the core was deformed, so that a low transmission loss was not obtained. . In Comparative Examples 2 and 3, the shape of the core portion could be formed with high accuracy, but the transmission loss was worse than that in Example 1.

Examples 2 and 3
Preparation and Evaluation of Dry Film After applying optical waveguide resin compositions Z-1 to Z-2 on a polyethylene terephthalate film (film thickness 25 μm) with a knife edge coater, the optical waveguide is dried at 80 ° C. for 30 minutes. Resin composition for dry film. Here, what was made into a dry film was "◯", and what was not made into a dry film was made into "x". Moreover, it transferred to the silicon substrate with the normal pressure hot roll press-bonding method (temperature of 100 degreeC) with respect to what was made into the dry film. As a result, “○” indicates that the film can be uniformly transferred onto the silicon substrate, the dry film partially remains on the base film, cannot be transferred onto the silicon substrate, or the transferred film is cracked. The case was set as “x”. The results are summarized in Table 3.

  As a result of the evaluation, in Examples 2 and 3, curable dry films for optical waveguides having film softening temperatures of 30 ° C. (Example 2) and 20 ° C. (Example 3) were obtained. Furthermore, when these dry films were transferred to a silicon substrate, they were uniform and good.

Comparative Examples 4-6
A dry film was produced in the same manner as in Examples 2 and 3 except that the optical waveguide resin compositions Z-3 to Z-5 were used.

  The results are shown in Table 3. In Comparative Example 4, an optical waveguide curable dry film having a film softening temperature of 80 ° C. was obtained. However, transfer to a silicon substrate was not possible. In Comparative Example 5, a curable dry film for optical waveguides having a film softening temperature of 40 ° C. could be obtained, but cracks and cracks were observed in some dry films. Moreover, although transfer to a silicon substrate was possible, cracks and cracks were observed in the transferred film. In Comparative Example 6, a curable dry film for optical waveguides could not be obtained. When the softening temperature of the composition of Comparative Example 6 was measured by TMA, it was −30 ° C. or lower.

Example 4
Formation and Evaluation of Optical Waveguide Using Dry Film A curable dry film for optical waveguide was prepared using curable resin compositions Z-1 and Z-2 for optical waveguide, and an optical waveguide was formed using these dry films.
Formation of lower cladding layer Transferable optical waveguide curable dry film ZD-2 made of optical waveguide curable resin composition Z-2 is transferred onto the surface of a silicon substrate by a normal pressure hot roll pressing method (temperature: 100 ° C.). Then, after irradiating ultraviolet rays having a wavelength of 365 nm and an illuminance of 200 mW / cm ² for 5 seconds, thermosetting was performed at 150 ° C. for 30 minutes to obtain a lower cladding layer having a thickness of 40 μm.

Formation of Core Portion Next, an optical waveguide curable dry film ZD-1 made of an optical waveguide curable resin composition Z-1 is applied to the lower cladding layer by a normal pressure hot roll pressing method (temperature: 100 ° C.). The dry film ZD-1 was partially cured by irradiating with ultraviolet rays having a wavelength of 365 nm and an illuminance of 10 mW / cm ² through a photomask having a line pattern of 30 μm width for 100 seconds. Subsequently, the substrate having ZD-1 irradiated with ultraviolet rays was immersed in a developer composed of a 1.8% tetramethylammonium hydroxide aqueous solution (TMAH) to dissolve the unexposed portion of the film. In this way, a core portion having a line pattern having a width of 30 μm was formed.

Formation of upper clad layer Next, a curable dry film for optical waveguide ZD-2 is transferred onto the upper surface of the lower clad layer having a core portion by a normal pressure hot roll pressure bonding method (temperature: 100 ° C.), and a hot plate is used. And prebaked at 120 ° C. for 30 minutes. Thereafter, the film made of ZD-2 was irradiated with ultraviolet rays having a wavelength of 365 nm and an illuminance of 200 mW / cm ² for 5 seconds, and postbaked at 150 ° C. for 30 minutes to produce an optical waveguide of Example 4.

  A conceptual cross-sectional view of the optical waveguide of Example 4 is as shown in FIG.

  The transmission loss evaluation (the same method as described above) of the optical waveguide manufactured in Example 4 was good at 0.21 dB / cm when the transmission loss was determined by the cutback method.

  In the formation of the core part (2), a line-like pattern having a width of 30 μm was formed in the same manner except that the post-cure was not performed. When the post-cure was performed, a pattern of 30 μm ± 3 μm was obtained. A pattern of ± 8 μm was obtained. That is, the post-cure improves the swelling resistance against the developing solution, and better core shape stability can be obtained.

  The present invention can be applied as a material for a curable dry film for forming an optical waveguide, in which an optical waveguide can be obtained without particularly reducing the processability and mechanical properties of the coating film.

It is sectional drawing seen from the side surface (thickness) and upper surface direction of the optical waveguide concerning this invention. Sectional drawing which looked at the cut surface of FIG. 1 from the near side is shown. The manufacturing method of the optical waveguide concerning this invention is shown.

Claims (5)

  (A) Carboxyl group-containing urethane compound, (B) polymerizable unsaturated compound, (C) two or more ring-opening polymerizable functional group-containing compounds in the molecule, and (D) a radiation polymerization initiator as essential components A curable resin composition for an optical waveguide, comprising:   (A) A carboxyl group-containing urethane compound is composed of a polyhydroxycarboxylic acid compound (a) and a polyisocyanate compound (b) containing two or more hydroxyl groups in one molecule and one or more carboxyl groups in one molecule. The curable resin composition for an optical waveguide according to claim 1, which is a reaction product.   (A) Carboxyl group-containing urethane compound, (B) polymerizable unsaturated compound, (C) two or more ring-opening polymerizable functional group-containing compounds in the molecule, and (D) a radiation polymerization initiator as essential components A dry film for forming an optical waveguide comprising a curable resin composition to be contained, wherein the dry film has a softening temperature of 0 ° C to 80 ° C.   A lower cladding layer, a core portion, and an upper cladding layer, wherein at least one of the lower cladding layer, the core portion, and the upper cladding layer is (A) a carboxyl group-containing urethane compound, and (B) polymerizable unsaturated A compound, (C) a curable resin composition containing two or more ring-opening polymerizable functional group-containing compounds in the molecule, and (D) a radiation polymerization initiator as an essential component, and a softening temperature of 0 ° C. to An optical waveguide formed using a dry film at 80 ° C.   5. The optical waveguide according to claim 4, wherein the refractive index difference between the clad layer and the core portion is 0.1% or more.

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