WO2017022055A1

WO2017022055A1 - Optical waveguide forming resin composition, optical waveguide forming resin film, and optical waveguide using these, and method for producing same

Info

Publication number: WO2017022055A1
Application number: PCT/JP2015/071973
Authority: WO
Inventors: 雅夫内ヶ崎; 大地酒井; 黒田　敏裕; 裕川上
Original assignee: 日立化成株式会社
Priority date: 2015-08-03
Filing date: 2015-08-03
Publication date: 2017-02-09

Abstract

The present invention pertains to an optical waveguide forming resin composition containing: (A) a polymer having an alkali-soluble group; (B) a compound having an ethylenically unsaturated group within the molecule thereof; and (C) a polymerization initiator, wherein component (B) contains at least one compound selected from (B1-1) to (B1-3) as component (B1), and a compound having, within the molecule thereof, an ethylenically unsaturated group and a group that reacts with the alkali-soluble group of component (A) as component (B2). (B1-1): A compound having three or more ethylenically unsaturated groups. (B1-2): A compound having a carboxy group and two or more ethylenically unsaturated groups. (B1-3): A compound having a urethane bond and one or more ethylenically unsaturated groups.

Description

Optical waveguide forming resin composition, optical waveguide forming resin film, optical waveguide using them, and method for producing the same

The present invention relates to a resin composition for forming an optical waveguide, a resin film for forming an optical waveguide, an optical waveguide using the same, and a method for producing the same, and in particular, it is excellent in transparency and environmental reliability by a high temperature and high humidity leaving test, and is alkaline. The present invention relates to a resin composition for forming an optical waveguide soluble in an aqueous solution, a resin film for forming an optical waveguide, an optical waveguide using them, and a method for producing the same.

In high-speed and high-density signal transmission between electronic elements, between wiring boards, etc., in conventional transmission using electrical wiring, mutual interference and attenuation of signals become barriers, and the limits of high-speed and high-density are beginning to appear. In order to overcome this, development of a technique for optically connecting electronic elements, wiring boards, etc., a so-called optical interconnection technique is underway. As an optical transmission line, a polymer optical waveguide has attracted attention because of its ease of processing, low cost, high degree of freedom of wiring, and high density.

As a form of the polymer optical waveguide, a rigid optical waveguide manufactured on a hard support substrate such as a glass epoxy resin that is assumed to be applied to an opto-electric hybrid substrate, or a flexible optical device that does not have a rigid support substrate assumed to be connected between boards Waveguides are considered suitable.
Furthermore, by using an opto-electric composite flexible wiring board in which a flexible wiring board and an optical waveguide are integrally combined, the degree of mounting freedom can be further improved.

Polymer optical waveguides are required to have heat resistance and environmental reliability as well as transparency (low light propagation loss) from the viewpoint of the environment in which the equipment is used, component mounting, and the like. In addition, the demand for toughness is increasing from the viewpoint of the strength and handleability of the optical waveguide. Furthermore, regarding the optical waveguide manufacturing process, a method capable of easily forming a pattern is required, and one of the methods is a pattern forming method by exposure and development widely used in a printed wiring board manufacturing process. Can do. As such a material, for example, optical waveguide materials containing (meth) acrylic polymers described in Patent Documents 1 to 4 are known.

However, the optical waveguide materials described in

Patent Documents

1 and 2 can be patterned by exposure and development, are transparent at a wavelength of 850 nm, and have good light propagation loss after a high temperature and high humidity test, but are required. This number is still insufficient for high-speed and high-density signal transmission by light. Moreover, although the optical waveguide material described in Patent Document 3 exhibits excellent optical transmission loss and has good heat resistance, it is brittle and does not satisfy the toughness. Further, although the optical waveguide materials described in

Patent Documents

4 and 5 have transparency at a wavelength of 850 nm and are excellent in toughness and the like, concrete examples such as light propagation loss in environmental reliability evaluation by a high temperature and high humidity standing test There is no specific description of the test results, and it is still not satisfactory.

JP 2006-146162 A JP 2008-33239 A JP 2006-71880 A JP 2007-1222023 A JP 2013-174776 A

In view of the above-described problems, the present invention provides a resin composition for an optical waveguide that is excellent in transparency at a wavelength of 850 nm and environmental reliability by a high-temperature and high-humidity standing test (hereinafter also simply referred to as “environmental reliability”), and formation of the optical waveguide. An object of the present invention is to provide an optical waveguide-forming resin film formed using a resin composition, an optical waveguide using the same, and a method for producing the same.

As a result of intensive studies, the present inventors have found that the above problem can be solved by using a resin composition for forming an optical waveguide containing a polymer having an alkali-soluble group, a compound having a specific ethylenically unsaturated group, and a polymerization initiator. Has been found to solve the problem, and the present invention has been achieved.

That is, the present invention relates to the following [1] to [18].
[1] An optical waveguide forming resin composition comprising (A) a polymer having an alkali-soluble group, (B) a compound having an ethylenically unsaturated group in the molecule, and (C) a polymerization initiator,
The component (B) is at least one compound selected from the following (B1-1) to (B1-3) as the component (B1) and the alkali-soluble group of the component (A) in the molecule as the component (B2) A resin composition for forming an optical waveguide, comprising a group that reacts with a compound and a compound having an ethylenically unsaturated group.
(B1-1) Compound having three or more ethylenically unsaturated groups (B1-2) Compound having carboxy group and two or more ethylenically unsaturated groups (B1-3) Urethane bond and one or more ethylene The resin composition for forming an optical waveguide according to the above [1], wherein the component [2] (B1-1) having an unsaturated group is a compound further having an isocyanurate ring in its molecule.
[3] The resin composition for forming an optical waveguide according to the above [1] or [2], wherein the component (B1-1) is a mixture of two or more compounds having different molecular weights.
[4] The component [B1-2] is a compound having two or more carboxy groups in the molecular chain and one or more ethylenically unsaturated groups at the molecular chain terminals. [3] The resin composition for forming an optical waveguide according to any one of [3].
[5] The component [B1-2] is a compound having a urethane bond and at least one ring structure selected from an alicyclic structure, an aromatic ring structure and a heterocyclic structure in the molecule. ] The resin composition for forming an optical waveguide according to any one of [4] to [4].
[6] The above [1] to [5], wherein the component (B1-3) is a compound having at least one ring structure selected from an alicyclic structure, an aromatic ring structure and a heterocyclic structure in the molecule. The resin composition for forming an optical waveguide according to any one of the above.
[7] The resin for forming an optical waveguide according to any one of the above [1] to [6], wherein the component (B1-3) includes a compound having a urethane bond and three or more ethylenically unsaturated groups. Composition.
[8] Any of the above [1] to [7], wherein the component (B2) is a compound having (B2-1) one or more epoxy groups and one or more ethylenically unsaturated groups in the molecule 2. A resin composition for forming an optical waveguide according to item 1.
[9] The resin composition for forming an optical waveguide according to the above [8], wherein the component (B2-1) is a compound further having an alicyclic structure or an aromatic ring structure in the molecule.
[10] The resin composition for forming an optical waveguide according to the above [8] or [9], wherein the component (B2-1) is a compound further having a bisphenol skeleton in the molecule.
[11] The resin composition for forming an optical waveguide according to any one of the above [1] to [10], wherein the component (A) is a polymer having a weight average molecular weight of 6,000 to 300,000.
[12] The resin composition for forming an optical waveguide according to any one of the above [1] to [11], wherein the component (A) is a polymer having a maleimide skeleton in the main chain.
[13] The content of component (A) is 10 to 85% by mass relative to the total amount of components (A) and (B), and the content of component (B) is the total amount of components (A) and (B). The mass ratio [(B1) / (B2)] of the component (B1) to the component (B2) is 50/50 to 85/15, and the content of the component (C) The resin composition for forming an optical waveguide according to any one of the above [1] to [12], wherein is 0.01 to 10 parts by mass with respect to 100 parts by mass of the total amount of the components (A) and (B) .
[14] An optical waveguide in which at least one of the lower cladding layer, the core portion, and the upper cladding layer is formed using the optical waveguide forming resin composition described in any one of [1] to [13].
[15] A resin film for forming an optical waveguide having a resin layer obtained by using the resin composition for forming an optical waveguide according to any one of [1] to [13].
[16] An optical waveguide in which at least one of the lower cladding layer, the core portion, and the upper cladding layer is formed using the optical waveguide forming resin film described in [15].
[17] The optical waveguide according to the above [14] or [16], wherein the light propagation loss at a wavelength of 850 nm is 0.25 dB / cm or less.
[18] An optical waveguide manufacturing method including the following steps 1 to 4, wherein at least one of the lower clad layer, the core portion, and the upper clad layer is used for the optical waveguide forming resin film described in [15] above. A method for manufacturing an optical waveguide.
Step 1: A step of laminating a resin film for forming a lower clad layer on a substrate to form a lower clad layer Step 2: A step of laminating a resin film for forming a core portion on the lower clad layer Step 3: The core portion Step of forming the core part after exposing the forming resin film through a photomask and then developing Step 4: The upper clad layer-forming resin film is laminated on the lower clad layer and the core part. Step of forming the cladding layer

According to the present invention, an optical waveguide resin composition excellent in transparency and environmental reliability at a wavelength of 850 nm, an optical waveguide forming resin film formed using this optical waveguide forming resin composition, an optical waveguide using them, and A manufacturing method thereof can be provided.

It is sectional drawing which shows the structural example of the optical waveguide of this invention. It is process sectional drawing which shows the manufacturing method of the optical waveguide which forms an optical waveguide using the resin film for optical waveguide formation of this invention for a lower clad layer, a core part, and an upper clad layer. It is the electron micrograph which shows the cross section of the optical waveguide of this invention, and the conventional optical waveguide, (a) is this invention, (b) is a prior art. Bleed is observed in the cross section of (b).

[Resin composition for optical waveguide formation]
The resin composition for forming an optical waveguide of the present invention comprises (A) a polymer having an alkali-soluble group, (B) a compound having an ethylenically unsaturated group in the molecule, and (C) an optical waveguide containing a polymerization initiator. A resin composition for
The component (B) is at least one compound selected from the following (B1-1) to (B1-3) as the component (B1) and the alkali-soluble group of the component (A) in the molecule as the component (B2) And a compound having an ethylenically unsaturated group.
(B1-1) Compound having three or more ethylenically unsaturated groups (B1-2) Compound having carboxy group and two or more ethylenically unsaturated groups (B1-3) Urethane bond and one or more ethylene Compound having an unsaturated group The resin composition for forming an optical waveguide of the present invention is preferably a resin composition that is cured by heating or irradiation with actinic rays.
Hereinafter, each component used in the present invention will be described.

<(A) Polymer having alkali-soluble group>
The resin composition for forming an optical waveguide of the present invention contains a polymer having an alkali-soluble group (hereinafter, also simply referred to as “component (A)”) as the component (A).
The component (A) has a property of being dissolved in an alkaline aqueous solution by having the alkali-soluble group, and a developer such as an alkaline aqueous solution or an aqueous developer (hereinafter also simply referred to as “developer”). In addition, there is no particular limitation as long as it has solubility to the extent that the desired development processing is performed.
The component (A) was obtained by applying a solution containing the component (A) to a substrate so that the film thickness after drying was 50 μm and then drying from the viewpoint of enabling development with an alkaline aqueous solution. When the coating is immersed in a 1% by mass aqueous potassium carbonate solution at 30 ° C. for 30 minutes and then washed with pure water, it may have alkali solubility to such an extent that the coating does not remain.
Examples of the alkali-soluble group include acidic substituents having a free hydrogen atom such as a carboxy group, a sulfonic acid group, a phenolic hydroxyl group, and an alcoholic hydroxyl group, and an amino group. From the viewpoint of solubility in an alkaline aqueous solution, an acidic substituent is preferable, and a carboxy group is more preferable.

Although there is no restriction | limiting in particular as (A) component, From a transparency viewpoint, heat resistance, and a soluble viewpoint to alkaline aqueous solution, an alkali-soluble (meth) acrylic polymer is preferable.
Examples of the alkali-soluble (meth) acrylic polymer of component (A) include (meth) acrylic acid; (meth) acrylic acid esters such as (meth) acrylic alkyl ester and (meth) acrylic acid hydroxyalkyl ester; Polymer having structural unit derived from (meth) acrylic monomer such as acrylamide, structural unit derived from (meth) acrylic monomer, and styrene, α-methylstyrene, maleic anhydride, N-substituted or unsubstituted maleimide Preferred is a copolymer having a structural unit derived from a polymerizable unsaturated group-containing monomer other than the (meth) acrylic monomer such as a monomer.
In the present specification, “(meth) acrylic polymer” means “acrylic polymer” or “methacrylic polymer”, and (meth) acrylic acid means “acrylic acid” or “methacrylic acid”. . The same applies to the following.

Among these, from the viewpoint of transparency, heat resistance, and solubility in an alkaline aqueous solution, a polymer having a maleimide skeleton derived from an N-substituted maleimide monomer in the main chain is preferable, and a polymer having a maleimide skeleton derived from an N-substituted maleimide monomer in the main chain. A (meth) acrylic polymer is more preferable, and a copolymer of a structural unit derived from an N-substituted maleimide monomer and a structural unit derived from another (meth) acrylic monomer is more preferable.
The (meth) acrylic polymer having a maleimide skeleton derived from an N-substituted maleimide monomer in the main chain is represented by the structural unit (A-1) represented by the following general formula (1) and the following general formula (2) in the main chain. A structural unit (A-3) represented by the following general formula (3) derived from a compound having a structural unit (A-2) and further having a carboxy group and an ethylenically unsaturated group, and the following general formula (4) It is preferable to use an alkali-soluble (meth) acrylic polymer having at least one of the structural units (A-4) represented by

(In the general formula (1), R ¹ to R ³ each independently represents a hydrogen atom or an organic group having 1 to 20 carbon atoms.)

(In general formula (2), R ⁴ to R ⁶ each independently represents a hydrogen atom or an organic group having 1 to 20 carbon atoms. R ⁷ represents an organic group having 1 to 20 carbon atoms.)

(In the general formula (3), R ⁸ to R ¹⁰ each independently represents a hydrogen atom or an organic group having 1 to 20 carbon atoms.)

(In the general formula (4), R ¹¹ to R ¹³ each independently represents a hydrogen atom or an organic group having 1 to 20 carbon atoms. X ¹ represents a divalent organic group having 1 to 20 carbon atoms. Show.)

Examples of the organic group having 1 to 20 carbon atoms in the general formulas (1) to (4) include an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, a carbonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, and a carbamoyl group. And monovalent or divalent groups such as They are further hydroxy groups, halogen atoms, alkyl groups, cycloalkyl groups, aryl groups, aralkyl groups, carbonyl groups, alkoxycarbonyl groups, aryloxycarbonyl groups, carbamoyl groups, alkoxy groups, aryloxy groups, alkylthio groups, arylthio groups. , An amino group, a silyl group and the like may be substituted.

The content of the structural unit (A-1) in the alkali-soluble (meth) acrylic polymer is preferably 3 to 50% by mass. When it is 3% by mass or more, heat resistance derived from maleimide is obtained, and when it is 50% by mass or less, the brittleness of the resulting resin pattern can be suppressed while sufficiently ensuring transparency. From the above viewpoint, 5 to 40% by mass is more preferable, and 10 to 30% by mass is further preferable.

The structural unit (A-1) is not particularly limited as long as it is represented by the general formula (1).
Examples of the maleimide as a raw material for the structural unit (A-1) include all those described in paragraph [0017] of Patent Document 5 (Japanese Patent Laid-Open No. 2013-174776).
Specifically, alkylmaleimides such as N-methylmaleimide and N-ethylmaleimide; hydroxyalkylmaleimides in which the hydrogen atom of the alkyl group is substituted with a hydroxy group; alicyclic rings such as N-cyclopropylmaleimide and N-cyclobutylmaleimide Mention may be made of the formula maleimide; arylmaleimides such as N-phenylmaleimide, N-2-methylphenylmaleimide, N-2-chlorophenylmaleimide and the like.

Among these, from the viewpoint of transparency and solubility, alicyclic maleimide is preferably used, and N-cyclohexylmaleimide or N-2-methylcyclohexylmaleimide is more preferably used.
These compounds can be used alone or in combination of two or more.

The content of the structural unit (A-2) in the alkali-soluble (meth) acrylic polymer is preferably 20 to 90% by mass. When it is 20% by mass or more, transparency derived from (meth) acrylate is obtained, and when it is 90% by mass or less, heat resistance is sufficient. From the above viewpoint, the content is more preferably 25 to 85% by mass, and further preferably 30 to 80% by mass.

The structure of the structural unit (A-2) is not particularly limited as long as it is represented by the general formula (2).
Examples of the (meth) acrylate used as the raw material for the structural unit (A-2) include all those described in paragraph [0020] of Patent Document 5 (Japanese Patent Laid-Open No. 2013-174776). Specifically, aliphatic (meth) acrylates such as methyl (meth) acrylate and ethyl (meth) acrylate; alicyclic (meth) acrylates such as cyclopentyl (meth) acrylate and cyclohexyl (meth) acrylate; benzyl (meth) Aromatic (meth) acrylates such as acrylate and phenyl (meth) acrylate; heterocyclic (meth) acrylates such as 2-tetrahydrofurfuryl (meth) acrylate and N- (meth) acryloyloxyethyl hexahydrophthalimide; Examples thereof include hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate; modified caprolactone thereof.

Among these, from the viewpoints of transparency and heat resistance, aliphatic (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, the alicyclic The formula (meth) acrylate, the aromatic (meth) acrylate, the heterocyclic (meth) acrylate, or the hydroxyalkyl (meth) acrylate is preferable, and the aromatic (meth) acrylate or hydroxyalkyl (meth) acrylate is more preferable. These compounds can be used alone or in combination of two or more.

In the alkali-soluble (meth) acrylic polymer, the total content of the structural units (A-3) and (A-4) derived from the compound having a carboxy group and an ethylenically unsaturated group is preferably 3 to 60% by mass. . If it is 3% by mass or more, it is easy to dissolve in the developer, and if it is 60% by mass or less, in the development step of selectively removing the layer of the photosensitive resin composition by development described later, The property (the property that the portion that becomes a pattern without being removed by development is not attacked by the developer) is improved. From the above viewpoint, the content is more preferably 5 to 50% by mass, and further preferably 10 to 40% by mass.

The structural unit (A-3) derived from the compound having a carboxy group and an ethylenically unsaturated group is not particularly limited as long as it is represented by the general formula (3).
Examples of the compound having a carboxy group and an ethylenically unsaturated group as a raw material for the structural unit (A-3) include (meth) acrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid, and mesaconic acid. , Cinnamic acid, and the like. Among these, (meth) acrylic acid, maleic acid, fumaric acid, or crotonic acid are preferable, and (meth) acrylic acid is more preferable from the viewpoint of transparency and alkali solubility.
Alternatively, maleic anhydride may be used as a raw material, and after the polymerization, ring opening may be performed with an appropriate alcohol such as methanol, ethanol, propanol, or the like to convert the structure into the structure of the structural unit (A-3). These compounds can be used alone or in combination of two or more.

The structural unit (A-4) derived from the compound having a carboxy group and an ethylenically unsaturated group is not particularly limited as long as it is represented by the general formula (4).
Examples of the compound having a carboxy group and an ethylenically unsaturated group as a raw material for the structural unit (A-4) include those described in paragraph [0023] of Patent Document 5 (Japanese Patent Laid-Open No. 2013-174776). Are all listed.
Among these, from the viewpoints of transparency and alkali solubility, mono (2- (meth) acryloyloxyethyl) succinate, mono (2- (meth) acryloyloxyethyl) tetrahydrophthalate, mono (2- (meth) acrylic acid). It is preferably leuoxyethyl) hexahydrophthalate, mono (2- (meth) acryloyloxyethyl) hexahydroisophthalate, mono (2- (meth) acryloyloxyethyl) hexahydroterephthalate, and the like. These compounds can be used alone or in combination of two or more.

The alkali-soluble (meth) acrylic polymer may contain structural units other than the structural units (A-1) to (A-4) as necessary.
The compound having an ethylenically unsaturated group as a raw material for such a structural unit is not particularly limited. For example, styrene, α-methylstyrene, vinyl toluene, vinyl chloride, vinyl acetate, vinyl pyridine, N-vinyl pyrrolidone, N -Vinylcarbazole, butadiene, isoprene, chloroprene and the like. Of these, styrene, α-methylstyrene, vinyltoluene, and N-vinylcarbazole are preferably used from the viewpoint of heat resistance and transparency.
These compounds can be used alone or in combination of two or more.

(A) The polymer having an alkali-soluble group is not particularly limited in its synthesis method. However, when an alkali-soluble (meth) acrylic polymer is used as the component (A), for example, a raw material for the structural unit (A-1) A maleimide, a (meth) acrylate as a raw material of the structural unit (A-2), a carboxy group and an ethylenically unsaturated group as at least one raw material of the structural units (A-3) and (A-4) It can be obtained by copolymerization using a compound having a suitable polymerization initiator and a compound having another ethylenically unsaturated group as required. Moreover, an organic solvent can be used as a reaction solvent as needed.

The polymerization initiator is not particularly limited, but is preferably a radical polymerization initiator, such as various ketone peroxides, peroxyketals, dialkyl peroxides, diacyl peroxides, peroxycarbonates, peroxyesters, azo Compounds and the like.

The organic solvent used as the reaction solvent is not particularly limited as long as it can dissolve the alkali-soluble (meth) acrylic polymer, and various aromatic hydrocarbons, cyclic ethers, ketones, esters, carbonates, polyhydric alcohols. Examples include alkyl ethers, polyhydric alcohol alkyl ether acetates, and amides. These organic solvents can be used alone or in combination of two or more.

The alkali-soluble (meth) acrylic polymer may contain an ethylenically unsaturated group in the side chain as necessary. The composition, synthesis method, etc. are not particularly limited. For example, the alkali-soluble (meth) acrylic polymer includes at least one ethylenically unsaturated group and an epoxy group, an oxetanyl group, an isocyanate group, a hydroxy group, a carboxy group, and the like. An ethylenically unsaturated group can be introduced into the side chain by addition reaction of a compound having two functional groups.

These compounds are not particularly limited, and include all those described in paragraph [0029] of Patent Document 5 (Japanese Patent Laid-Open No. 2013-174776). Namely, compounds having various ethylenically unsaturated groups and epoxy groups, compounds having ethylenically unsaturated groups and oxetanyl groups, compounds having ethylenically unsaturated groups and isocyanate groups, compounds having ethylenically unsaturated groups and hydroxy groups And compounds having an ethylenically unsaturated group and a carboxy group.
Among these, from the viewpoint of transparency and reactivity, glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, ethyl isocyanate (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2- Hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, (meth) acrylic acid, crotonic acid, and 2-hexahydrophthaloylethyl (meth) acrylate are preferred. These compounds can be used alone or in combination of two or more.

(A) The polymer having an alkali-soluble group preferably has a weight average molecular weight of 6,000 to 300,000. When the molecular weight is 6,000 or more, the strength of the cured product is sufficient when the resin composition is used, and when it is 300,000 or less, the solubility in the developer and the compatibility with the component (B) are high. It is good. From the above viewpoint, it is more preferably 6,000 to 200,000, and further preferably 10,000 to 100,000. The weight average molecular weight in the present invention is a value measured by gel permeation chromatography (GPC) and converted to standard polystyrene.

(A) The polymer having an alkali-soluble group has an acid value so that it can be developed with various known developing solutions in the step of selectively removing a layer of the photosensitive resin composition by development described later. Can be defined. For example, when developing using an alkaline aqueous solution such as sodium carbonate, potassium carbonate, tetramethylammonium hydroxide, triethanolamine, the acid value of the polymer (A) having an alkali-soluble group is 20 to 300 mgKOH / g. It is preferable. When it is 20 mgKOH / g or more, development is easy, and when it is 300 mgKOH / g or less, a decrease in developer resistance can be suppressed. From the above viewpoint, it is more preferably 30 to 250 mgKOH / g, and further preferably 40 to 200 mgKOH / g.

When developing using an aqueous developer comprising water or an aqueous alkaline solution and one or more surfactants, the acid value of the polymer (A) having an alkali-soluble group is preferably 10 to 260 mgKOH / g. . When the acid value is 10 mgKOH / g or more, development is easy, and when it is 260 mgKOH / g or less, the developer resistance is not lowered. From the above viewpoint, it is more preferably 20 to 250 mgKOH / g, and further preferably 30 to 200 mgKOH / g.

In the resin composition for forming an optical waveguide of the present invention, the content of the component (A) is preferably 10 to 85% by mass with respect to the total amount of the components (A) and (B). If it is 10% by mass or more, the strength and flexibility of the cured product of the resin composition for forming an optical waveguide are sufficient, and if it is 85% by mass or less, the polymer of the component (A) is formed by the component (B) during exposure. It is easily entangled and hardened, and the developer resistance is not insufficient. From the above viewpoint, it is more preferably 15% by mass or more, and further preferably 20% by mass or more. Moreover, it is more preferable that it is 75 mass% or less, and it is further more preferable that it is 65 mass% or less. Further, from the viewpoint of low light loss, the range of 10 to 65% by mass is particularly preferable.

<(B) Compound having ethylenically unsaturated group in molecule>
The resin composition for forming an optical waveguide of the present invention contains (B) a compound having an ethylenically unsaturated group in the molecule (hereinafter, also simply referred to as “component (B)”). The component (B) comprises at least one compound selected from the following (B1-1) to (B1-3) as the component (B1) and an alkali of the polymer of the component (A) in the molecule as the component (B2) Combined use of a group that reacts with a soluble group and a compound having an ethylenically unsaturated group can improve the toughness of the cured film, and further, a bleed out during a reliability test using a high temperature and high humidity standing test. Can be suppressed.
(B1-1) Compound having three or more ethylenically unsaturated groups (B1-2) Compound having carboxy group and two or more ethylenically unsaturated groups (B1-3) Urethane bond and one or more ethylene Compound having an unsaturated group Examples of the ethylenically unsaturated group include a vinyl group, an allyl group, a butenyl group, a cyclohexenyl group, a cyclopentadienyl group, a (meth) acryloyloxyalkyl group, and the like. At least one selected from (meth) acryloyloxyalkyl groups is preferred.
In the present specification, “(meth) acryloyloxyalkyl group” means “acryloyloxyalkyl group” or “methacryloyloxyalkyl group”. The same applies to the following.

The content of the component (B) in the optical waveguide forming resin composition of the present invention is preferably 15 to 90% by mass relative to the total amount of the components (A) and (B). If it is 15% by mass or more, bleeding out during a reliability test can be suppressed, and if it is 90% by mass or less, the toughness of the cured film can be maintained. From the above viewpoint, it is more preferably 25% by mass or more, and further preferably 35% by mass or more. Moreover, it is more preferable that it is 85 mass% or less, and it is further more preferable that it is 80 mass% or less. From the viewpoint of low light loss, the range of 35 to 90% by mass is particularly preferable.
The mass ratio [(B1) / (B2)] of the component (B1) to the component (B2) in the optical waveguide forming resin composition of the present invention is preferably 50/50 to 85/15. If it is 50/50 or more, bleed-out during the reliability test can be suppressed, and if it is 85/15 or less, the toughness of the cured film can be maintained. From the above viewpoint, the ratio is more preferably 60/40 to 80/20, and further preferably 65/35 to 75/25. From the viewpoint of low light loss, the range of 65/35 to 75/25 is particularly preferable.

<(B1) component>
[(B1-1) component]
In the present invention, as the component (B1), (B1-1) a compound having three or more ethylenically unsaturated groups and as the component (B2) react with the alkali-soluble group of the component (A) in the molecule. By using in combination with a group and a compound having an ethylenically unsaturated group, the toughness of the cured film can be improved.

(B1-1) The compound having three or more ethylenically unsaturated groups (hereinafter, also simply referred to as “component (B1-1)”) is not particularly limited, and examples thereof include trimethylolpropane tri (meth) acrylate. , Ethoxylated trimethylolpropane tri (meth) acrylate, propoxylated trimethylolpropane tri (meth) acrylate, ethoxylated propoxylated trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ethoxylated pentaerythritol tri ( (Meth) acrylate, propoxylated pentaerythritol tri (meth) acrylate, ethoxylated propoxylated pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ethoxylated pentaerythris Aliphatic (meth) such as tall tetra (meth) acrylate, propoxylated pentaerythritol tetra (meth) acrylate, ethoxylated propoxylated pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol hexa (meth) acrylate Acrylates; heterocyclic (meth) acrylates such as ethoxylated isocyanuric acid tri (meth) acrylate, propoxylated isocyanuric acid tri (meth) acrylate, ethoxylated propoxylated isocyanuric acid tri (meth) acrylate; these caprolactone modified products; phenol Aromatic epoxy (meth) acrylates such as novolak type epoxy tri (meth) acrylate and cresol novolak type epoxy tri (meth) acrylate They include a (meth) acrylate.

Among these, from the viewpoint of transparency and heat resistance, heterocyclic (such as ethoxylated isocyanuric acid tri (meth) acrylate, propoxylated isocyanuric acid tri (meth) acrylate, ethoxylated propoxylated isocyanuric acid tri (meth) acrylate) ( A compound having three ethylenically unsaturated groups, such as aromatic epoxy (meth) acrylates such as a phenol novolac type epoxy (meth) acrylate and a cresol novolac type epoxy tri (meth) acrylate; Preferably, ethoxylated isocyanuric acid tri (meth) acrylate, propoxylated isocyanuric acid tri (meth) acrylate, ethoxylated propoxylated isocyanuric acid tri (meth) acrylate, etc. More preferably a compound having an over preparative ring, ethoxylated isocyanuric acid tri (meth) acrylate is more preferred.
These compounds can be used alone or in combination of two or more kinds, and can also be used in combination with other compounds having three or more ethylenically unsaturated groups. As another compound having three or more ethylenically unsaturated groups, a compound having a urethane bond in the molecule is preferable, urethane (meth) acrylate is more preferable, and ethoxylated isocyanuric acid tri ( More preferably, the (meth) acrylate (a1) and the urethane (meth) acrylate (a2) having three or more ethylenically unsaturated groups are used in combination.
The mass ratio [(a1) / (a2)] of the (a1) component to the (a2) component in the resin composition for forming an optical waveguide of the present invention is preferably 20/80 to 70/30. If it is 20/80 or more, the flexibility of the cured film can be maintained, and if it is 70/30 or less, the toughness of the cured film can be maintained. From the above viewpoint, the ratio is more preferably 30/70 to 65/35, and further preferably 40/60 to 60/40.

The component (B1-1) is preferably a mixture of two or more compounds having different molecular weights. Specifically, the component (a3) having a weight average molecular weight of 100 or more and less than 1,000 is combined with the component (a4) having a weight average molecular weight of 1,000 to 10,000. Is more preferable. By using the said mixture, the softness | flexibility and toughness of the film after hardening can be made compatible.
The mass ratio [(a3) / (a4)] of the (a3) component to the (a4) component in the resin composition for forming an optical waveguide of the present invention is preferably 20/80 to 70/30. If it is 20/80 or more, the flexibility of the cured film can be maintained, and if it is 70/30 or less, the toughness of the cured film can be maintained. From the above viewpoint, the ratio is more preferably 30/70 to 65/35, and further preferably 40/60 to 60/40.

The content of the component (B1-1) in the optical waveguide forming resin composition of the present invention is preferably 10 to 85% by mass with respect to the total amount of the components (A) and (B). When the content is 10% by mass or more, crosslinking due to photocuring becomes high density, and precipitation of unreacted substances during an environmental reliability test (hereinafter also simply referred to as “environmental reliability test”) by a high temperature and high humidity standing test is small. Moreover, if it is 85 mass% or less, the film strength and flexibility of a cured film are enough. From the above viewpoint, the content is more preferably 13 to 70% by mass, and further preferably 15 to 50% by mass. Further, from the viewpoint of suppressing the warp of the cured film, the range of 15 to 30% by mass is particularly preferable.

[(B1-2) component]
In the present invention, the compound (B1-2) having a carboxy group and two or more ethylenically unsaturated groups as the component (B1) and the alkali-soluble group of the component (A) in the molecule as the component (B2) By using in combination with a group having an ethylenically unsaturated group, the toughness of the cured film can be improved, and bleeding out during a reliability test can be suppressed.

(B1-2) A compound having a carboxy group and two or more ethylenically unsaturated groups (hereinafter, also simply referred to as “component (B1-2)”) includes a carboxy group and two or more ethylenic groups in the molecule. There is no particular limitation as long as it is a photoradical reactive compound having an unsaturated group. For example, an esterified product of an epoxy compound (b1) and an unsaturated monocarboxylic acid (b2) is saturated with an unsaturated polybasic acid anhydride (b3). An addition reaction product to which is added) can be used. These can be obtained by a two-step reaction. In the first reaction (hereinafter referred to as “first reaction” for convenience), the epoxy compound (b1) and the unsaturated monocarboxylic acid (b2) react. In the next reaction (hereinafter referred to as “second reaction” for convenience), the esterified product formed in the first reaction and the saturated or unsaturated polybasic acid anhydride (b3) react.

As the component (B1-2) that can be used in the present invention, EA-6340, EA-7140, EA-7440 (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd.), CCR-1218H, CCR-1159H, CCR- 1222H, PCR-1050, TCR-1335H, ZAR-1035, ZAR-2001H, ZFR-1185, UXE-3024 and ZCR-1569H (Nippon Kayaku Co., Ltd., trade name), UE-EXP-2810, UE EXP-3073 (trade name, manufactured by DIC Corporation) is commercially available.

The acid value of the component (B1-2) can be regulated so that it can be developed with a developer. The acid value of the component (B1-2) is preferably 5 to 200 mgKOH / g. When it is 5 mgKOH / g or more, the solubility in a developer is good, and when it is 200 mgKOH / g or less, the developer resistance is good. From the above viewpoint, the acid value of the component (B1-2) is more preferably 10 to 150 mgKOH / g, further preferably 15 to 100 mgKOH / g, and particularly preferably 20 to 50 mgKOH / g. preferable.

The weight average molecular weight of the component (B1-2) is preferably 1,000 to 100,000. When the resin composition is 1,000 or more, the strength of the cured product is sufficient, and if it is 100,000 or less, the solubility in the developer and the compatibility with other compounds contained in the component (B) Becomes better. From the above viewpoints, it is more preferably 2,000 to 50,000, further preferably 3,000 to 25,000, particularly preferably 3,000 to 10,000, and 3,000. It is particularly preferred that the number is less than 6,000.
The weight average molecular weight of the component (B1-2) is a value measured by gel permeation chromatography (GPC) and converted to standard polystyrene.

Component (B1-2) is a compound having two or more carboxy groups in the molecular chain and one or more ethylenically unsaturated groups at the molecular chain ends from the viewpoint of solubility in a developer. It is more preferable that the compound has two or more carboxy groups in the molecular chain and has an ethylenically unsaturated group at both ends of the molecular chain.
The component (B1-2) has two or more ethylenically unsaturated groups in the molecule from the viewpoint of improving the toughness of the cured film and suppressing bleed out during the reliability test. The number is preferably one or less, and more preferably two.

(B1-2) As the compound having a carboxy group and two or more ethylenically unsaturated groups, those having a urethane bond in the molecule may be used from the viewpoint of flexibility.
The compound having a carboxy group, two or more ethylenically unsaturated groups, and a urethane bond is not particularly limited, and examples thereof include urethane (meth) acrylates represented by the following (I) to (IV). .

(I) Urethane (meth) acrylate obtained by reacting a bifunctional alcohol compound, a bifunctional isocyanate compound, and a (meth) acrylate having a hydroxyl group.
(II) Urethane (meth) acrylate obtained by reacting a bifunctional alcohol compound, a bifunctional isocyanate compound, and a (meth) acrylate having an isocyanate group.
(III) Urethane (meth) acrylate obtained by reacting a polyfunctional isocyanate compound and (meth) acrylate having a hydroxyl group.
(IV) Urethane (meth) acrylate obtained by reacting a polyfunctional alcohol compound and a (meth) acrylate having an isocyanate group.
(However, in any of (I) to (IV), any raw material compound has a carboxy group.)
Among these, from the viewpoints of transparency and heat resistance, urethane (meth) having a urethane bond and at least one ring structure selected from an alicyclic structure, an aromatic ring structure, and a heterocyclic structure in the molecule. Acrylate is preferred. As said ring structure, an alicyclic structure is preferable and a cyclohexane ring is more preferable.

Examples of the bifunctional alcohol compound, that is, the diol compound, include a carboxy group-containing diol compound, and may further include a polyether diol compound, a polyester diol compound, a polycarbonate diol compound, a polycaprolactone diol compound, and the like. .

The carboxy group-containing diol compound is not particularly limited, and examples thereof include 2,2-dimethylolbutanoic acid, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolpentanoic acid, and the like. Is mentioned. These compounds can be used alone or in combination of two or more.

The polyether diol compound is not particularly limited, and examples thereof include ethylene oxide, propylene oxide, isobutene oxide, butyl glycidyl ether, butene-1-oxide, 3,3-bischloromethyloxetane, tetrahydrofuran, 2-methyltetrahydrofuran, 3 A polyether diol compound obtained by ring-opening (co) polymerizing at least one selected from cyclic ether compounds such as methyltetrahydrofuran, cyclohexene oxide, styrene oxide, phenyl glycidyl ether, glycidyl benzoate; cyclohexanedimethanol, An alicyclic diol compound such as tricyclodecane dimethanol, hydrogenated bisphenol A, hydrogenated bisphenol F or the like is selected from the above cyclic ether compounds. Polyether diol compound obtained by ring-opening addition of one kind; at least selected from the above cyclic ether compounds as a bifunctional phenol compound such as hydroquinone, resorcinol, catechol, bisphenol A, bisphenol F, bisphenol AF, biphenol, and fluorene bisphenol Examples include polyether diol compounds obtained by ring-opening addition of one kind.

The polyester diol compound is not particularly limited. For example, malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, tetrahydrophthalic acid, hexahydrophthalic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, Bifunctional carboxylic acid compounds such as fumaric acid and itaconic acid, ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butanediol, dibutanediol, polybutanediol, pentanediol, neopentylglycol, 3-methyl-1,5-pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, cyclohexanedimethanol, tricyclodeca Polyester diol compounds obtained by copolymerizing a diol compound of dimethanol, etc., and the like.

The polycarbonate diol compound is not particularly limited, and examples thereof include phosgene, triphosgene, dialkyl carbonate, diaryl carbonate and the like, ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butanediol, dibutanediol. , Polybutanediol, pentanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, cyclohexanedimethanol, tricyclodecanedimethanol, hydrogenated Polycarbonatediol obtained by copolymerizing diol compounds such as bisphenol A and hydrogenated bisphenol F Such compounds.

The polycaprolactone diol compound is not particularly limited. For example, ε-caprolactone and ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butanediol, dibutanediol, polybutanediol, and pentane. Copolymerizes with diol compounds such as diol, neopentyl glycol, 3-methyl-1,5-pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, cyclohexanedimethanol, and tricyclodecanedimethanol. And polycaprolactone diol compounds obtained by the above.

Examples of other diol compounds include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butanediol, dibutanediol, pentanediol, neopentylglycol, 3-methyl-1,5-pentanediol, hexanediol, and heptane. Aliphatic diol compounds such as diol, octanediol, nonanediol, decanediol; cycloaliphatic diol compounds such as cyclohexanedimethanol, tricyclodecanedimethanol, hydrogenated bisphenol A, hydrogenated bisphenol F; polybutadiene-modified diol compounds, water Examples thereof include modified diol compounds such as an additive polybutadiene-modified diol compound and diricone-modified diol compound. These diol compounds can be used alone or in combination of two or more.

The bifunctional isocyanate compound is not particularly limited, and examples thereof include aliphatic bifunctional isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, decamethylene diisocyanate, and dodecamethylene diisocyanate. 1,3-bis (isocyanatomethyl) cyclohexane, isophorone diisocyanate, 2,5-bis (isocyanatomethyl) norbornene, bis (4-isocyanatocyclohexyl) methane, 1,2-bis (4-isocyanatocyclohexyl) Ethane, 2,2-bis (4-isocyanatocyclohexyl) propane, 2,2-bis (4-isocyanatocyclohexyl) hexafluoropropane,

bicycloheptane triisocyanate

2,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, naphthalene-1,5-diisocyanate, o And aromatic bifunctional isocyanate compounds such as xylylene diisocyanate and m-xylylene diisocyanate. These compounds can be used alone or in combination of two or more.

The (meth) acrylate having a hydroxyl group is not particularly limited, and examples thereof include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, 2- Hydroxybutyl (meth) acrylate, 1,4-cyclohexanedimethanol mono (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2-hydroxy-3- (o-phenylphenoxy) propyl (meth) acrylate Monofunctional (meth) acrylates such as 2-hydroxy-3- (1-naphthoxy) propyl (meth) acrylate and 2-hydroxy-3- (2-naphthoxy) propyl (meth) acrylate, ethoxylated products thereof, and the like The propoxylated form of this Ethoxylated propoxy compounds thereof, and modified caprolactone thereof; bifunctional (meth) acrylates such as bis (2- (meth) acryloyloxyethyl) (2-hydroxyethyl) isocyanurate, ethoxylated compounds thereof, These propoxy compounds, these ethoxylated propoxy compounds, and their caprolactone modified products: cyclohexanedimethanol type epoxy di (meth) acrylate, tricyclodecane dimethanol type epoxy di (meth) acrylate, hydrogenated bisphenol A type epoxy di ( (Meth) acrylate, hydrogenated bisphenol F type epoxy di (meth) acrylate, hydroquinone type epoxy di (meth) acrylate, resorcinol type epoxy di (meth) acrylate, catechol type epoxy di (meth) acrylate, bis Enol A type epoxy di (meth) acrylate, bisphenol F type epoxy di (meth) acrylate, bisphenol AF type epoxy di (meth) acrylate, biphenol type epoxy di (meth) acrylate, fluorene bisphenol type epoxy di (meth) acrylate, isocyanuric acid monoallyl type epoxy di ( Bifunctional epoxy (meth) acrylates such as (meth) acrylate; trifunctional or more (meth) acrylates such as pentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and the like Ethoxylated compounds, their propoxylated compounds, their ethoxylated propoxylated compounds, and their caprolactone-modified products; Examples thereof include tri- or higher functional epoxy (meth) acrylates such as poxy (meth) acrylate, cresol novolac type epoxy poly (meth) acrylate, and isocyanuric acid type epoxy tri (meth) acrylate. These compounds can be used alone or in combination of two or more.

Here, the (meth) acrylate ethoxylated product, propoxylated product, and ethoxylated propoxylated product are the above alcohol compound or phenol compound instead of the alcohol compound or phenol compound used as the raw material of (meth) acrylate, respectively. An alcohol compound having a structure in which one or more ethylene oxides are added, an alcohol compound having a structure in which one or more propylene oxides are added, or an alcohol compound having a structure in which one or more ethylene oxides and propylene oxide are added are used as raw materials ( (Meth) acrylate is shown.
For example, in the case of monofunctional (meth) acrylate; CH ₂ ═CH (R ¹⁴ ) —COO—R ¹⁵ (wherein R ¹⁴ is a hydrogen atom or a methyl group, R ¹⁵ is a monovalent organic group), the raw material HO— CH ₂ ═CH (R ¹⁴ ) —COO— (CH ₂ CH ₂ O) _q obtained by using an alcohol compound having a structure in which one or more ethylene oxides are added to the alcohol compound instead of the alcohol compound represented by R ¹⁵ -R ¹⁵ (q is an integer of 1 or more, and R ¹⁴ and R ¹⁵ are the same as above).
The caprolactone-modified product refers to (meth) acrylate obtained by using, as a raw material, an alcohol compound obtained by modifying an alcohol compound that is a raw material for (meth) acrylate with ε-caprolactone. For example, in the case of a caprolactone modified product of monofunctional (meth) acrylate, CH ₂ ═CH (R ¹⁴ ) —COO — ((CH ₂ ) ₅ COO) _q —R ¹⁵ (q, R ¹⁴ , R ¹⁵ are the same as above. ).

The (meth) acrylate having an isocyanate group is not particularly limited. For example, N- (meth) acryloyl isocyanate, (meth) acryloyloxymethyl isocyanate, 2- (meth) acryloyloxyethyl isocyanate, 2- (meth) Examples include acryloyloxyethoxyethyl isocyanate and 1,1-bis ((meth) acryloyloxymethyl) ethyl isocyanate. These compounds can be used alone or in combination of two or more.

The polyfunctional isocyanate compound is not particularly limited, and examples thereof include bifunctional isocyanate compounds; multimers such as uretdione dimers, isocyanurate types, biuret trimers of the bifunctional isocyanate compounds, and the like. . The two or three bifunctional isocyanate compounds constituting the multimer may be the same or different. These compounds can be used alone or in combination of two or more.

The polyfunctional alcohol compound is not particularly limited. For example, the bifunctional alcohol compound; trifunctional or more functional groups such as trimethylolpropane, pentaerythritol, ditrimethylolpropane, dipentaerythritol, tris (2-hydroxyethyl) isocyanurate Alcohol compounds, adducts obtained by ring-opening addition of at least one selected from the cyclic ether compounds to these, caprolactone-modified products thereof; cyclic compounds with trifunctional or higher functional phenol compounds such as phenol novolac and cresol novolak Examples include alcohol compounds obtained by ring-opening addition of at least one selected from ether compounds, and modified caprolactones thereof. These compounds can be used alone or in combination of two or more.

The component (B1-2) has a carboxy group and two or more ethylenically unsaturated groups from the viewpoint of improving the toughness of the cured film and suppressing bleed out during a reliability test, A compound having a urethane bond therein and at least one ring structure selected from an alicyclic structure, an aromatic ring structure, and a heterocyclic structure is preferable. As said ring structure, an alicyclic structure is preferable and a cyclohexane ring is more preferable.

Among these, (I) a bifunctional alcohol compound, a bifunctional isocyanate compound, and a (meth) acrylate having a hydroxyl group are reacted from the viewpoint of improving the toughness of the cured film and suppressing bleed-out during a reliability test. The urethane (meth) acrylate obtained is preferable, and in the (I), the carboxy group-containing diol compound as a bifunctional alcohol compound, the aliphatic bifunctional isocyanate compound as a bifunctional isocyanate compound, and a (meth) acrylate having a hydroxyl group More preferred is urethane (meth) acrylate obtained by reacting the monofunctional (meth) acrylate.

The component (B1-2) has a carboxy group and two ethylenically unsaturated groups from the viewpoint of improving the toughness of the cured film and suppressing bleed-out during a reliability test, and further in its molecule. A urethane (meth) acrylate having a urethane bond and at least one ring structure selected from an alicyclic structure, an aromatic ring structure, and a heterocyclic structure is preferable. As said ring structure, an alicyclic structure is preferable and a cyclohexane ring is more preferable.

The content of the component (B1-2) in the optical waveguide forming resin composition of the present invention is preferably 10 to 85% by mass with respect to the total amount of the components (A) and (B). When it is 10% by mass or more, the polymer of the component (A) can be easily entangled and cured, and the developer resistance is not insufficient. Moreover, if it is 85 mass% or less, the film strength and flexibility of a cured film are enough. From the above viewpoint, the content is more preferably 13 to 70% by mass, further preferably 15 to 50% by mass, and particularly preferably 15 to 30% by mass.

[(B1-3) component]
In the present invention, (B1) component (B1-3) has a urethane bond and one or more ethylenically unsaturated groups as component (B1), and (B2) component reacts with the alkali-soluble group of component (A) in the molecule. By using together a compound having a group and an ethylenically unsaturated group, the toughness and flexibility of the cured film can be improved.

(B1-3) The compound having a urethane bond and one or more ethylenically unsaturated groups (hereinafter also simply referred to as “component (B1-3)”) is not particularly limited, and examples thereof include the following (V) to And urethane (meth) acrylate represented by (VIII).
(V) Urethane (meth) acrylate obtained by reacting a bifunctional alcohol compound, a bifunctional isocyanate compound, and a (meth) acrylate having a hydroxyl group.
(VI) Urethane (meth) acrylate obtained by reacting a bifunctional alcohol compound, a bifunctional isocyanate compound, and a (meth) acrylate having an isocyanate group.
(VII) Urethane (meth) acrylate obtained by reacting a polyfunctional isocyanate compound and a (meth) acrylate having a hydroxyl group.
(VIII) A urethane (meth) acrylate obtained by reacting a polyfunctional alcohol compound and a (meth) acrylate having an isocyanate group.
The above-mentioned compounds are preferred as the bifunctional alcohol compound, the bifunctional isocyanate compound, the (meth) acrylate having the hydroxyl group, the (meth) acrylate having the isocyanate group, and the polyfunctional isocyanate compound.

Among these, from the viewpoint of transparency and heat resistance, a compound having at least one ring structure selected from an alicyclic structure, an aromatic ring structure and a heterocyclic structure in the molecule is preferable, and a urethane having a heterocyclic structure (Meth) acrylate is more preferable, and urethane (meth) acrylate having an isocyanurate ring is more preferable.

In addition, the component (B1-3) preferably has two or more ethylenically unsaturated groups in the molecule from the viewpoint of developer resistance and environmental reliability, and preferably three or more. More preferably, the number is three.
Furthermore, it is preferable to include a compound having a urethane bond and three or more ethylenically unsaturated groups as the component (B1-3), and urethane (meth) acrylate (c1) having two ethylenically unsaturated groups in the molecule. And a mixed system with urethane (meth) acrylate (c2) having three ethylenically unsaturated groups. By setting it as such a combination, the flexibility of hardened | cured material can be improved in addition to developing solution resistance and environmental reliability.
The mass ratio [(c1) / (c2)] of the (c1) component to the (c2) component in the optical waveguide forming resin composition of the present invention is preferably 50/50 to 85/15. If it is 50/50 or more, bleeding out during the reliability test can be suppressed and the toughness of the cured film can be maintained, and if it is 85/15 or less, the flexibility of the cured film is maintained. can do. From the above viewpoint, the ratio is more preferably 60/40 to 80/20, and further preferably 65/35 to 75/25.

The component (B1-3) may further have a carboxy group in the molecule as necessary from the viewpoint of heat resistance and solubility in a developer.
The (meth) acrylate having a carboxy group and a urethane bond as (B1-3) is not particularly limited. For example, when synthesizing the urethane (meth) acrylate described above, the carboxy group-containing diol compound is combined with the diol compound. Examples thereof include urethane (meth) acrylate obtained in combination or in place of the diol compound.
The carboxy group-containing diol compound is not particularly limited, and examples thereof include 2,2-dimethylolbutanoic acid, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolpentanoic acid, and the like. Can be mentioned.
These compounds can be used alone or in combination of two or more.

The acid value of the (meth) acrylate having a carboxyl group and a urethane bond as (B1-3) can be regulated so that it can be developed with a developer. The acid value of the component (B1-3) is preferably 5 to 200 mgKOH / g. When it is 5 mgKOH / g or more, the solubility in a developer is good, and when it is 200 mgKOH / g or less, the developer resistance is good. From the above viewpoint, the acid value of the (meth) acrylate having a carboxy group and a urethane bond as the component (B1-3) is more preferably 10 to 150 mgKOH / g, and more preferably 15 to 100 mgKOH / g. Further preferred is 20 to 50 mg KOH / g.

The content of the component (B1-3) in the resin composition for forming an optical waveguide of the present invention is preferably 10 to 85% by mass with respect to the total amount of the components (A) and (B). When it is 10% by mass or more, the polymer of the component (A) can be easily entangled and cured, and the developer resistance is not insufficient. Moreover, if it is 85 mass% or less, the film strength and flexibility of a cured film are enough. From the above viewpoint, the content is more preferably 13 to 70% by mass, further preferably 15 to 50% by mass, and particularly preferably 20 to 50% by mass.

The component (B1) is a compound (b1-1) having three ethylenically unsaturated groups as the component (B1-1) (excluding those having a urethane bond, hereinafter, simply referred to as “component (b1-1)”. And a compound (b1-2) having a carboxy group and two ethylenically unsaturated groups as components (B1-2) (hereinafter also simply referred to as “component (b1-2)”), (B1- It is preferable to use a compound (b1-3) having a urethane bond and three ethylenically unsaturated groups (hereinafter also simply referred to as “(b1-3) component”) as the component 3). Thereby, the toughness of the cured film can be improved, and further, bleed out during a reliability test can be suppressed.
The total amount of the component (b1-1), the component (b1-2) and the component (b1-3) is preferably 80% by mass or more, more preferably 90% by mass or more based on the total amount of the component (B1). More preferably, it is 100 mass%.
The content of the component (b1-2) is from 100 to 100 parts by mass with respect to 100 parts by mass of the component (b1-1) from the viewpoint of improving the toughness of the cured film and suppressing bleed out during the reliability test. 300 parts by mass is preferable, and 150 to 250 parts by mass is more preferable.
The content of the component (b1-3) is preferably 10 to 200 parts by mass with respect to 100 parts by mass of the component (b1-1), from the viewpoint of toughness and flexibility of the cured film. 150 parts by mass is more preferable.

The component (b1-1) is preferably a compound having an isocyanurate ring in its molecule, and more preferably ethoxylated isocyanuric acid tri (meth) acrylate.
The component (b1-2) is preferably a compound having two or more carboxy groups in the molecular chain and one or more ethylenically unsaturated groups at the molecular chain ends, and further having a urethane bond in the molecule, A compound having at least one ring structure selected from an alicyclic structure, an aromatic ring structure, and a heterocyclic structure is more preferable, and a urethane (meth) acrylate having an alicyclic structure is more preferable. As said alicyclic structure, a cyclohexane ring is preferable.
The component (b1-3) is preferably a compound having at least one ring structure selected from an alicyclic structure, an aromatic ring structure, and a heterocyclic structure in the molecule, and a urethane (meth) acrylate having a heterocyclic structure. Is more preferable. The ring structure is more preferably an isocyanurate ring.

<(B2) component>
The resin composition for forming an optical waveguide of the present invention is a compound having an ethylenically unsaturated group and a group that reacts with the alkali-soluble group of the component (A) in the molecule as the component (B2) together with the component (B1). Hereinafter, it is simply referred to as “component (B2)”.
In the present invention, the component (B2) is a compound other than the component (B1).
The group that reacts with the alkali-soluble group is preferably an epoxy group, and the component (B2) includes (B2-1) a compound having one or more epoxy groups and one or more ethylenically unsaturated groups in the molecule. Is preferably used. For example, an epoxy (meth) acrylate obtained by reacting an epoxy resin having two or more epoxy groups in one molecule with a (meth) acrylic acid compound is mentioned, and a (meth) acrylic acid compound with respect to 1 equivalent of the epoxy group Is preferably reacted with 0.1 to 0.9 equivalent, more preferably 0.2 to 0.8 equivalent, and still more preferably 0.4 to 0.6 equivalent.

Specifically, bisphenol A type epoxy (meth) acrylate, tetrabromobisphenol A type epoxy (meth) acrylate, bisphenol F type epoxy (meth) acrylate, bisphenol AF type epoxy (meth) acrylate, bisphenol AD type epoxy (meth) acrylate , Epoxy (meth) acrylates derived from bifunctional phenol glycidyl ethers such as biphenyl type epoxy (meth) acrylate, naphthalene type epoxy (meth) acrylate, fluorene type epoxy (meth) acrylate; hydrogenated bisphenol A type epoxy (meth) acrylate, Hydrogenated bisphenol F type epoxy (meth) acrylate, hydrogenated 2,2'-biphenol type epoxy (meth) acrylate, hydrogenated 4,4'-biphenol type epoxy ( A) Epoxy (meth) acrylate derived from hydrogenated bifunctional phenol glycidyl ether such as acrylate; phenol novolac type epoxy (meth) acrylate, cresol novolac type epoxy (meth) acrylate, dicyclopentadiene-phenol type epoxy (meth) acrylate, Epoxy (meth) acrylate derived from polyfunctional phenol glycidyl ether such as tetraphenylol ethane type epoxy (meth) acrylate; polyethylene glycol type epoxy (meth) acrylate, polypropylene glycol type epoxy (meth) acrylate, neopentyl glycol type epoxy (meta ) Epoxy derived from bifunctional aliphatic alcohol glycidyl ether such as acrylate, 1,6-hexanediol type epoxy (meth) acrylate (Meth) acrylate; epoxy (meth) acrylate derived from bifunctional alicyclic alcohol glycidyl ether such as cyclohexanedimethanol type epoxy (meth) acrylate, tricyclodecane dimethanol type epoxy (meth) acrylate; trimethylolpropane type epoxy ( Epoxy (meth) acrylate derived from polyfunctional aliphatic alcohol glycidyl ether such as meth) acrylate, sorbitol type epoxy (meth) acrylate, glycerin type epoxy (meth) acrylate; derived from bifunctional aromatic glycidyl ester such as diglycidyl phthalate Epoxy (meth) acrylates: Epoxys derived from bifunctional alicyclic glycidyl esters such as tetrahydrophthalic acid diglycidyl ester and hexahydrophthalic acid diglycidyl ester ( And (meth) acrylate.

Among these, from the viewpoint of high refractive index, transparency, and heat resistance, compounds having an alicyclic structure or an aromatic ring structure in the molecule are preferred, and bisphenol A type epoxy (meth) acrylate, bisphenol F type epoxy (meta ) Acrylate, bisphenol AF type epoxy (meth) acrylate, bisphenol AD type epoxy (meth) acrylate, biphenyl type epoxy (meth) acrylate, naphthalene type epoxy (meth) acrylate, fluorene type epoxy (meth) acrylate, etc. bifunctional phenol glycidyl Epoxy derived from polyfunctional phenol glycidyl ether of ether-derived epoxy (meth) acrylate, phenol novolac type epoxy (meth) acrylate, cresol novolac type epoxy (meth) acrylate In at least one molecule selected from bifunctional alicyclic alcohol glycidyl ether-derived epoxy (meth) acrylates such as acrylate, cyclohexanedimethanol type epoxy (meth) acrylate, and tricyclodecane dimethanol type epoxy (meth) acrylate An epoxy (meth) acrylate having an alicyclic structure or an aromatic ring structure is more preferable, and a compound having a bisphenol skeleton in the molecule is more preferable.

The content of the component (B2) in the resin composition for forming an optical waveguide of the present invention is preferably 1 to 40% by mass with respect to the total amount of the components (A) and (B). When it is 1% by mass or more, it is easy to entangle and cure the polymer having an alkali-soluble group of component (A), and there is little precipitation of unreacted substances during the environmental reliability test. Moreover, if it is 40 mass% or less, the film strength and flexibility of a cured film are enough. From the above viewpoint, the content is more preferably 10 to 30% by mass.

[(B3) component]
In addition to the components (B1) and (B2) described above, the resin composition of the present invention contains, as a component (B3), in a molecule other than the components (B1) and (B2) from the viewpoint of developability and heat resistance. A compound having two or more ethylenically unsaturated groups (hereinafter, also simply referred to as “component (B3)”) may be contained. Thereby, a crosslinking reaction is accelerated | stimulated, bridge | crosslinking becomes dense, immersion of the developing solution to a hardening part is suppressed, and it can suppress that an exposure part melt | dissolves at the time of image development. As a result, when the core portion is formed, it is possible to suppress a decrease in the film thickness of the core portion, and to form a core pattern having a good substantially rectangular cross-sectional shape without rounding the edges of the core pattern.

Examples of the compound having two or more ethylenically unsaturated groups in the molecule other than the components (B1) and (B2) as the component (B3) include (meth) acrylate, vinylidene halide, vinyl ether, vinyl ester, Examples thereof include vinyl pyridine, vinyl amide, and arylated vinyl. Among these, (meth) acrylate and arylated vinyl are preferable from the viewpoint of transparency. As the (meth) acrylate, bifunctional (meth) acrylate or polyfunctional (meth) acrylate may be used.

Examples of the bifunctional (meth) acrylate include all those described in paragraph [0040] of Patent Document 5 (Japanese Patent Laid-Open No. 2013-174776).
Among these, from the viewpoints of transparency and heat resistance, the alicyclic (meth) acrylates; aromatic (meth) acrylates; complex mentioned in paragraph [0040] of Patent Document 5 (Japanese Patent Application Laid-Open No. 2013-174776) Cyclic (meth) acrylates; alicyclic epoxy (meth) acrylates; aromatic epoxy (meth) acrylates are preferred. These compounds can be used alone or in combination of two or more. Furthermore, it can also be used in combination with other compounds having an ethylenically unsaturated group.

Examples of the trifunctional or higher polyfunctional (meth) acrylate include all those described in paragraph [0041] of Patent Document 5 (Japanese Patent Laid-Open No. 2013-174776).
Among these, from the viewpoints of transparency and heat resistance, the heterocyclic (meth) acrylates mentioned in paragraph [0041] of Patent Document 5 (Japanese Patent Laid-Open No. 2013-174776); aromatic epoxy (meth) acrylates Preferably there is.
These compounds can be used alone or in combination of two or more. Furthermore, it can also be used in combination with other compounds having an ethylenically unsaturated group.

<(C) Polymerization initiator>
The resin composition for forming an optical waveguide of the present invention contains a polymerization initiator (hereinafter also simply referred to as “component (C)”) as the component (C).
(C) The polymerization initiator is not particularly limited as long as it initiates polymerization by heating, irradiation with ultraviolet rays or the like, and examples thereof include a thermal radical polymerization initiator and a photo radical polymerization initiator. In particular, a radical photopolymerization initiator is preferred because of its high curing rate and room temperature curing.

Examples of the thermal radical polymerization initiator include ketone peroxides such as methyl ethyl ketone peroxide, cyclohexanone peroxide, and methylcyclohexanone peroxide; 1,1-bis (t-butylperoxy) cyclohexane, 1,1-bis (t- Butylperoxy) -2-methylcyclohexane, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1- Peroxyketals such as bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane; hydroperoxides such as p-menthane hydroperoxide; α, α′-bis (t-butylperoxy) diisopropylbenzene , Dicumyl peroxide, t-butylcumylperoxy Dialkyl peroxides such as di-t-butyl peroxide; diacyl peroxides such as octanoyl peroxide, lauroyl peroxide, stearyl peroxide, benzoyl peroxide; bis (4-t-butylcyclohexyl) peroxydicarbonate, Peroxycarbonates such as di-2-ethoxyethyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-3-methoxybutyl peroxycarbonate; t-butyl peroxypivalate, t-hexyl peroxypi Valate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, t-hexylperoxy -2-Ethylhexanoe Tate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, t-hexylperoxyisopropylmonocarbonate, t-butylperoxy-3,5,5-trimethylhexanoate T-butyl peroxylaurate, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-butyl peroxybenzoate, t-hexyl peroxybenzoate, 2,5-dimethyl- Peroxyesters such as 2,5-bis (benzoylperoxy) hexane and t-butylperoxyacetate; 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile) ), 2,2′-azobis (4-methoxy-2′-dimethyl) Such as Le valeronitrile) azo compounds, and the like.
Among these, from the viewpoints of curability, transparency, and heat resistance, the diacyl peroxide; the peroxy ester; and the azo compound are preferable.

Examples of radical photopolymerization initiators include benzoin ketals such as 2,2-dimethoxy-1,2-diphenylethane-1-one; 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropane- Α-hydroxy ketones such as 1-one, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one; 2-benzyl-2-dimethylamino-1 Α-amino ketones such as-(4-morpholinophenyl) -butan-1-one, 1,2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one; Oxime esters such as (4-phenylthio) phenyl] -1,2-octadion-2- (benzoyl) oxime; bis (2,4,6-tri Phosphine oxides such as methylbenzoyl) phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide; 2- (o-chlorophenyl) ) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di (methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer 2,4,5-triaryl such as 2-mer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer Imidazole dimer; benzophenone, N, N'-tetramethyl-4,4'-diame Benzophenone compounds such as nobenzophenone, N, N′-tetraethyl-4,4′-diaminobenzophenone, 4-methoxy-4′-dimethylaminobenzophenone; 2-ethylanthraquinone, phenanthrenequinone, 2-tert-butylanthraquinone, octamethyl Anthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,3-diphenylanthraquinone, 1-chloroanthraquinone, 2-methylanthraquinone, 1,4-naphthoquinone, 9,10-phenant Quinone compounds such as laquinone, 2-methyl-1,4-naphthoquinone and 2,3-dimethylanthraquinone; benzoin ethers such as benzoin methyl ether, benzoin ethyl ether and benzoin phenyl ether Benzoin compounds such as benzoin, methylbenzoin and ethylbenzoin; benzyl compounds such as benzyldimethyl ketal; acridine compounds such as 9-phenylacridine and 1,7-bis (9,9'-acridinylheptane): N-phenyl; Examples include glycine and coumarin.

In the 2,4,5-triarylimidazole dimer, the substituents of the aryl groups at the two triarylimidazole sites may give the same and symmetric compounds, but give differently asymmetric compounds. May be. Also. A thioxanthone compound and a tertiary amine may be combined, such as a combination of diethylthioxanthone and dimethylaminobenzoic acid.

Among these, from the viewpoint of curability, transparency, and heat resistance, the α-hydroxyketone and the phosphine oxide are preferable. These radical polymerization initiators can be used alone or in combination of two or more. Furthermore, it can also be used in combination with an appropriate sensitizer.

In addition, when a compound having an epoxy group is used as the compound having an ethylenically unsaturated group in the molecule (B), in order to use the epoxy group as a polymerizable group, You may use cationic polymerization initiators, such as a thermal cationic polymerization initiator and a photocationic polymerization initiator. In particular, a cationic photopolymerization initiator is preferred because it has a high curing rate and can be cured at room temperature.

Examples of the thermal cationic polymerization initiator include benzylsulfonium salts such as p-alkoxyphenylbenzylmethylsulfonium hexafluoroantimonate; benzyl-p-cyanopyridinium hexafluoroantimonate, 1-naphthylmethyl-o-cyanopyridinium hexafluoroantimony And pyridinium salts such as cinnamyl-o-cyanopyridinium hexafluoroantimonate; and benzylammonium salts such as benzyldimethylphenylammonium hexafluoroantimonate.
Among these, the benzylsulfonium salt is preferable from the viewpoint of curability, transparency, and heat resistance.

Examples of the cationic photopolymerization initiator include aryl diazonium salts such as p-methoxybenzenediazonium hexafluorophosphate, diaryliodonium salts such as diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate; triphenylsulfonium hexafluorophosphate, triphenyl Triarylsulfonium salts such as sulfonium hexafluoroantimonate, diphenyl-4-thiophenoxyphenylsulfonium hexafluorophosphate, diphenyl-4-thiophenoxyphenylsulfonium hexafluoroantimonate, diphenyl-4-thiophenoxyphenylsulfonium pentafluorohydroxyantimonate ; Triphenylselenonium hexa Triarylselenonium salts such as fluorophosphate, triphenylselenonium tetrafluoroborate, triphenylselenonium hexafluoroantimonate; dialkylphenacyl such as dimethylphenacylsulfonium hexafluoroantimonate, diethylphenacylsulfonium hexafluoroantimonate Sulfonium salts; dialkyl-4-hydroxy salts such as 4-hydroxyphenyldimethylsulfonium hexafluoroantimonate and 4-hydroxyphenylbenzylmethylsulfonium hexafluoroantimonate; α-hydroxymethylbenzoin sulfonate, N-hydroxyimide sulfonate, α -Sulfonyloxy ketone, sulfonic acid ester such as β-sulfonyloxy ketone, and the like.
Among these, from the viewpoints of curability, transparency, and heat resistance, the triarylsulfonium salt is preferable.

These cationic polymerization initiators can be used alone or in combination of two or more. Furthermore, it can also be used in combination with an appropriate sensitizer.

The content of the component (C) in the resin composition for forming an optical waveguide of the present invention is preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the total amount of the components (A) and (B). . Curing is sufficient when it is 0.01 parts by mass or more, and sufficient light transmission is obtained when it is 10 parts by mass or less. From the above viewpoint, the content is more preferably 0.1 to 10 parts by mass, further preferably 0.3 to 7 parts by mass, and particularly preferably 0.5 to 5 parts by mass.

In addition, if necessary, the resin composition for forming an optical waveguide of the present invention comprises an antioxidant, an anti-yellowing agent, an ultraviolet absorber, a visible light absorber, a colorant, a plasticizer, a stabilizer, and a filling agent. You may contain what is called additives, such as an agent, in the range which does not inhibit the effect of this invention.

(Resin varnish for optical waveguide formation)
The resin composition for forming an optical waveguide of the present invention may be diluted with an organic solvent and used as a resin varnish for forming an optical waveguide.
The organic solvent is not particularly limited as long as it can dissolve each raw material constituting the resin composition for forming an optical waveguide of the present invention. For example, an aromatic such as toluene, xylene, mesitylene, cumene, p-cymene, etc. Aromatic hydrocarbons; cyclic ethers such as tetrahydrofuran and 1,4-dioxane; alcohols such as methanol, ethanol, isopropanol, butanol, ethylene glycol, propylene glycol; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 4-hydroxy-4-methyl -2- ketones such as pentanone; esters such as methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate and γ-butyrolactone; carbonates such as ethylene carbonate and propylene carbonate; ethylene glycol monomethyl ether Ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether Polyhydric alcohol alkyl ethers such as diethylene glycol monobutyl ether, diethylene glycol dimethyl ether and diethylene glycol diethyl ether; ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether Polyhydric alcohol alkyl ether acetates such as teracetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate; N, N-dimethylformamide, N, N-dimethylacetamide, N -Amides such as methylpyrrolidone.

Among these, from the viewpoint of solubility and boiling point, toluene, methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, ethylene glycol monomethyl ether, Ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol dimethyl ether, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, or N, N-dimethylacetamide is preferred. These organic solvents can be used alone or in combination of two or more. The solid content concentration in the optical waveguide forming resin varnish is preferably 20 to 80% by mass.

When preparing the resin varnish for forming an optical waveguide, it is preferable to mix by stirring. Although there is no restriction | limiting in particular in the stirring method, From the viewpoint of stirring efficiency, stirring using a propeller is preferable. There is no particular limitation on the rotation speed of the propeller during stirring, but it is preferably 10 to 1,000 min ⁻¹ . When it is 10 min ⁻¹ or more, the components (A) to (C), other components, and the organic solvent are sufficiently mixed, and when it is 1,000 min ⁻¹ or less, bubbles are involved by rotation of the propeller. Less. From the above viewpoint, it is more preferably 50 to 800 min ⁻¹ , further preferably 100 to 500 min ⁻¹ . The stirring time is not particularly limited, but is preferably 1 to 24 hours. When it is 1 hour or longer, the components (A) to (C), other components, and the organic solvent are sufficiently mixed, and when it is 24 hours or shorter, the varnish preparation time can be shortened.

The prepared resin varnish for forming an optical waveguide is preferably filtered using a filter having a pore diameter of 50 μm or less. When the pore diameter is 50 μm or less, large foreign matters and the like are removed, and no repelling or the like occurs during varnish application, and scattering of light propagating through the core portion is suppressed. From the above viewpoint, it is more preferable to filter using a filter having a pore diameter of 30 μm or less, and it is more preferable to filter using a filter having a pore diameter of 10 μm or less.

The prepared resin varnish for forming an optical waveguide is preferably degassed under reduced pressure. There is no restriction | limiting in particular in the defoaming method, As a specific example, a degassing apparatus with a vacuum pump and a bell jar and a vacuum apparatus can be used. Although there is no restriction | limiting in particular in the pressure at the time of pressure reduction, The pressure which the organic solvent contained in a resin varnish does not boil is preferable. There is no particular limitation on the vacuum degassing time, but it is preferably 3 to 60 minutes. If it is 3 minutes or longer, bubbles dissolved in the resin varnish can be removed. If it is 60 minutes or less, the organic solvent contained in the resin varnish will not volatilize.

The refractive index of the cured film obtained by polymerizing and curing the optical waveguide forming resin composition of the present invention in the wavelength range of 830 to 850 nm at a temperature of 25 ° C. is preferably 1.400 to 1.700. If the refractive index is 1.400 to 1.700, the refractive index is not significantly different from that of a normal resin composition for forming an optical waveguide, so that versatility as an optical waveguide forming material is not impaired. From the above viewpoints, it is more preferably 1.425 to 1.675, and further preferably 1.450 to 1.650.

The transmittance at a wavelength of 850 nm of a 50 μm thick cured film obtained by polymerizing and curing the optical waveguide forming resin composition of the present invention is preferably 80% or more. If it is 80% or more, the amount of transmitted light is sufficient. From the above viewpoint, it is more preferably 85% or more, and further preferably 90% or more. Note that the upper limit of the transmittance is not particularly limited.

[Resin film for optical waveguide formation]
The resin film for forming an optical waveguide of the present invention has a resin layer for forming an optical waveguide (hereinafter also simply referred to as “resin layer”) obtained using the resin composition for forming an optical waveguide of the present invention. The resin film for forming an optical waveguide of the present invention is used as at least one of a lower cladding layer, a core portion, and an upper cladding layer from the viewpoint of suppressing light propagation loss at 850 nm of the optical waveguide and improving environmental reliability. it can. From the above viewpoint, it is preferable to use as at least one of the lower clad layer and the upper clad layer.
The resin film for forming an optical waveguide of the present invention can be easily produced by applying the resin composition for forming an optical waveguide of the present invention to a substrate film and removing the solvent as necessary.
Further, from the viewpoint of productivity, the resin varnish for forming an optical waveguide may be directly applied to a base film to remove the solvent.

There is no restriction | limiting in particular as a base film, For example, Polyester, such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; Polyolefin, such as polyethylene and a polypropylene; Polycarbonate, polyamide, polyimide, polyamideimide, polyetherimide, polyether sulfide , Polyethersulfone, polyetherketone, polyphenylene ether, polyphenylene sulfide, polyarylate, polysulfone, liquid crystal polymer and the like.
Among these, from the viewpoint of flexibility and toughness, it may be polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polypropylene, polycarbonate, polyamide, polyimide, polyamideimide, polyphenylene ether, polyphenylene sulfide, polyarylate, or polysulfone. preferable.

The thickness of the base film may be appropriately changed depending on the intended flexibility, but is preferably 3 to 250 μm. When it is 3 μm or more, the film strength is sufficient, and when it is 250 μm or less, sufficient flexibility is obtained. From the above viewpoint, the thickness is more preferably 5 to 200 μm, further preferably 7 to 150 μm.
In addition, from the viewpoint of improving the peelability from the resin layer, a film that has been subjected to a release treatment with a silicone compound, a fluorine-containing compound, or the like may be used as necessary.

The resin film for forming an optical waveguide of the present invention may have a structure including a three-layer structure having a base film, a resin layer, and a protective film in this order, if necessary. Is a structure composed of the three-layer structure.

The protective film is not particularly limited, and examples thereof include polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyolefins such as polyethylene and polypropylene. Among these, from the viewpoints of flexibility and toughness, polyesters such as polyethylene terephthalate; polyolefins such as polyethylene and polypropylene are preferable. In addition, from the viewpoint of improving the peelability from the resin layer, a film that has been subjected to a release treatment with a silicone compound, a fluorine-containing compound, or the like may be used as necessary. The thickness of the protective film may be appropriately changed depending on the intended flexibility, but is preferably 10 to 250 μm. When it is 10 μm or more, the strength of the protective film is sufficient, and when it is 250 μm or less, sufficient flexibility is obtained. From the above viewpoint, the thickness is more preferably 15 to 200 μm, and further preferably 20 to 150 μm.

The thickness of the resin layer of the resin film for forming an optical waveguide of the present invention is not particularly limited, but the thickness after drying is preferably 5 to 500 μm. If the thickness is 5 μm or more, the resin film or the cured product of the film has sufficient strength because the thickness is sufficient, and if it is 500 μm or less, the drying can be performed sufficiently and the amount of residual solvent in the resin film increases. Without foaming when the cured product of the film is heated.

The resin film for forming an optical waveguide thus obtained can be used as a film for forming at least one of a lower clad layer, a core portion, and an upper clad layer, and can be easily stored by, for example, winding in a roll shape. can do. Alternatively, a roll-shaped film can be cut into a suitable size and stored in a sheet shape.

[Optical waveguide]
The optical waveguide of the present invention is an optical waveguide in which at least one of the lower cladding layer, the core portion, and the upper cladding layer is formed using the optical waveguide forming resin composition of the present invention or the optical waveguide forming resin film of the present invention. It is. The resin composition for forming an optical waveguide of the present invention is used as at least one of a lower cladding layer, a core portion, and an upper cladding layer from the viewpoint of suppressing light propagation loss at 850 nm of the optical waveguide and improving environmental reliability. Can do. From the above viewpoint, it is preferable to use as at least one of the lower clad layer and the upper clad layer.

FIG. 1A is a sectional view of the optical waveguide 1 of the present invention. The optical waveguide 1 is formed on a substrate 5 and is formed of a core part 2 formed from a core part-forming resin composition having a high refractive index, and a lower part formed from a resin composition for forming a cladding layer having a low refractive index. The clad layer 4 and the upper clad layer 3 are configured.
The resin composition for forming an optical waveguide or the resin film for forming an optical waveguide of the present invention can be used for at least one of the lower cladding layer 4, the core portion 2 and the upper cladding layer 3 of the optical waveguide 1. Among these, from the viewpoint that a pattern can be formed with a developer, it can be suitably used for the core part 2, and because of excellent heat resistance and environmental reliability, it is also suitable for a clad layer that covers and protects the core periphery. It is.

By using the optical waveguide forming resin composition of the present invention, it is possible to further improve the interlayer adhesion between the clad and the core, the pattern formability (correspondence between fine lines or narrow lines) at the time of forming the optical waveguide core pattern, and the like. Thus, it is possible to form a small fine pattern such as a line width and a line spacing. In addition, it is possible to provide a process with excellent productivity in which a large-area optical waveguide can be manufactured at one time.

In the optical waveguide 1, a hard substrate such as a silicon substrate, a glass substrate, or a glass epoxy resin substrate such as FR-4 can be used as the base material 5.
Moreover, the optical waveguide 1 is good also as a flexible optical waveguide using the said base film with a softness | flexibility and toughness as the base material 5. FIG.
When the base film having flexibility and toughness is used as the base material 5, the base film may function as a cover film for the optical waveguide 1. By disposing a base film serving as a cover film, flexibility and toughness can be imparted to the optical waveguide 1. In addition, since the optical waveguide 1 is not damaged or scratched, the handleability is improved.
From the above viewpoint, a base film 5 serving as a cover film is disposed outside the upper clad layer 3 as shown in FIG. 1B, or the lower clad layer 4 and the upper portion as shown in FIG. A base film 5 serving as a cover film may be disposed on both outer sides of the clad layer 3.
Further, when the optical waveguide 1 has sufficient flexibility and toughness, the base film 5 serving as the cover film may not be disposed as shown in FIG.

The thickness of the lower cladding layer 4 is not particularly limited, but is preferably 2 to 200 μm, more preferably 5 to 100 μm, and even more preferably 7 to 80 μm. When it is 2 μm or more, it becomes easy to confine propagating light inside the core, and when it is 200 μm or less, it is possible to suppress an excessive increase in the thickness of the entire optical waveguide 1.
The thickness of the lower cladding layer 4 is a value from the boundary between the core portion 2 and the lower cladding layer 4 to the lower surface of the lower cladding layer 4.
The thickness of the optical waveguide forming resin film used for forming the lower clad layer 4 is not particularly limited, and may be appropriately adjusted so that the thickness of the lower clad layer 4 after curing falls within the above range.

The height of the core part 2 is not particularly limited, but is preferably 10 to 100 μm. When the height of the core portion is 10 μm or more, the alignment tolerance is not reduced in the coupling with the light emitting / receiving element or the optical fiber after the optical waveguide is formed. In the coupling with the light emitting / receiving element or the optical fiber, the coupling efficiency is not reduced. From the above viewpoint, the height of the core part is more preferably 15 to 80 μm, and further preferably 20 to 70 μm.
In addition, the thickness of the resin film for forming an optical waveguide used for forming the core part 2 is not particularly limited, and may be appropriately adjusted so that the height of the core part 2 after curing is in the above range.

The thickness of the upper cladding layer 3 is not particularly limited as long as the core portion 2 can be embedded, but the thickness after drying is preferably 12 to 500 μm, more preferably 20 to 150 μm. preferable. The thickness of the upper clad layer 3 may be the same as or different from the thickness of the lower clad layer 4 that is formed first, but is thicker than the thickness of the lower clad layer 4 from the viewpoint of embedding the core portion 2. It is preferable.
The thickness of the upper cladding layer 3 is a value from the boundary between the core portion 2 and the lower cladding layer 4 to the upper surface of the upper cladding layer 3.
The thickness of the resin film for forming an optical waveguide used for forming the upper cladding layer 3 is not particularly limited, and may be appropriately adjusted so that the thickness of the upper cladding layer 3 after curing is in the above range.

In the optical waveguide of the present invention, the light propagation loss at a wavelength of 850 nm is preferably 0.25 dB / cm or less, and more preferably 0.15 dB / cm or less. When the light propagation loss is 0.25 dB / cm or less, the light loss is reduced and the strength of the transmission signal is sufficient.

[Optical Waveguide Manufacturing Method]
The method for producing the optical waveguide of the present invention is not particularly limited. For example, the resin composition for forming an optical waveguide of the present invention or the resin varnish for forming an optical waveguide of the present invention is used for forming a resin varnish for forming a core part and a cladding layer. Use as a resin varnish, a method of producing by a spin coating method, etc., a method of producing an optical waveguide forming resin film of the present invention by using a core part forming resin film and a cladding layer forming resin film, a lamination method, etc. Is mentioned. Moreover, it can also manufacture combining these methods. Among these, it is preferable to manufacture by the lamination method using the resin film for optical waveguide formation from a viewpoint that the optical waveguide manufacturing process excellent in productivity can be provided.

The optical waveguide manufacturing method of the present invention is an optical waveguide manufacturing method having the following steps 1 to 4 from the viewpoint that an optical waveguide manufacturing process with excellent productivity can be provided, and includes a lower cladding layer, a core portion, and an upper portion. At least one of the cladding layers is preferably formed using the resin film for forming an optical waveguide of the present invention.
Step 1: A step of laminating a resin film for forming a lower clad layer on a substrate to form a lower clad layer Step 2: A step of laminating a resin film for forming a core portion on the lower clad layer Step 3: The core portion Step of forming the core part after exposing the forming resin film through a photomask and then developing Step 4: The upper clad layer-forming resin film is laminated on the lower clad layer and the core part. Step of forming the cladding layer

Hereinafter, a manufacturing method for forming the optical waveguide 1 using the resin film for forming an optical waveguide of the present invention for the lower clad layer 4, the core portion 2 and the upper clad layer 3 will be described with reference to FIG.
The base material used in the process of producing the core portion forming resin film is not particularly limited as long as it can transmit the actinic ray for exposure used in the core pattern formation described later. For example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate. Polyester such as phthalate; polyolefin such as polyethylene and polypropylene; polycarbonate, polyphenylene ether, polyarylate and the like.
Among these, polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyolefins such as polypropylene are preferable from the viewpoints of the transmittance of exposure actinic rays, flexibility, and toughness. Furthermore, it is more preferable to use a highly transparent base film from the viewpoint of improving the transmittance of exposure actinic rays and reducing the side wall roughness of the core pattern. Examples of such highly transparent base film include Cosmo Shine A1517 and Cosmo Shine A4100 manufactured by Toyobo Co., Ltd. In addition, from the viewpoint of improving the peelability from the resin layer, a film that has been subjected to a release treatment with a silicone compound, a fluorine-containing compound, or the like may be used as necessary.

The thickness of the base film of the core portion forming resin film is preferably 5 to 50 μm. If it is 5 μm or more, the strength as a support is sufficient, and if it is 50 μm or less, the gap between the photomask and the resin composition layer for forming the core part does not increase when the core pattern is formed, and the pattern formability is good. is there. From the above viewpoint, the thickness of the base film is more preferably 10 to 40 μm, and further preferably 15 to 30 μm.

An optical waveguide-forming resin film produced by applying an optical waveguide-forming resin composition or an optical waveguide-forming resin varnish on the base film is prepared by applying the protective film on the resin layer as necessary. It is good also as a 3 layer structure which consists of a material film, a resin layer, and a protective film.

The core part-forming resin film thus obtained can be easily stored by, for example, winding it into a roll. Alternatively, a roll-shaped film can be cut into a suitable size and stored in a sheet shape.

(Process 1)
FIG. 2 is a process cross-sectional view illustrating the method of manufacturing an optical waveguide according to the present invention.
First, as step 1, as shown in FIG. 2A, a lower cladding layer 4 is formed by laminating a resin film for forming a lower cladding layer on a substrate 5.
Examples of the laminating method in Step 1 include a method of laminating by heating and pressure bonding using a roll laminator or a flat plate laminator, but from the viewpoint of adhesion and followability, using a flat plate laminator under reduced pressure. It is preferable to laminate a resin film for forming a lower clad layer. In the present invention, the flat plate type laminator refers to a laminator in which a laminated material is sandwiched between a pair of flat plates and pressed by pressing the flat plate. For example, a vacuum pressurizing laminator can be suitably used. The heating temperature here is preferably 40 to 130 ° C., and the pressing pressure is preferably 0.1 to 1.0 MPa, but these conditions are not particularly limited. When a protective film exists in the resin film for forming the lower cladding layer, the protective film is laminated after removing the protective film.

It should be noted that a resin film for forming a lower clad layer may be temporarily pasted on the substrate 5 in advance using a roll laminator before lamination with a vacuum pressure laminator. Here, from the viewpoint of improving adhesion and followability, it is preferable to perform temporary bonding while pressing, and when pressing, a laminator having a heat roll may be used while heating. The laminating temperature is preferably 20 to 130 ° C. When it is 20 ° C. or higher, the adhesion between the resin film for forming the lower clad layer 4 and the substrate 5 is improved, and when it is 130 ° C. or lower, the resin layer does not flow too much during roll lamination, and the required film Thickness is obtained. From the above viewpoint, the laminating temperature is more preferably 40 to 100 ° C. The pressure is preferably 0.2 to 0.9 MPa and the laminating speed is preferably 0.1 to 3 m / min, but these conditions are not particularly limited.

Subsequently, the lower clad layer forming resin film laminated on the base material 5 is cured by light or heating, the base film of the lower clad layer forming resin film is removed, and the lower clad layer 4 is formed.
The irradiation amount of actinic rays when forming the lower cladding layer 4 is preferably 0.1 to 5 J / cm ^2, and the heating temperature is preferably 50 to 200 ° C. There is no limit.

(Process 2)
Next, as step 2, as shown in FIG. 2B, the core portion forming resin film 7 is laminated by the same method as in step 1. Here, the core part-forming resin film 7 is preferably made of a photosensitive resin composition that is designed to have a higher refractive index than that of the lower clad layer-forming resin film and can form a core pattern with actinic rays.
Since the resin composition for forming an optical waveguide of the present invention has photosensitivity, it is suitable as a resin film for forming a core part.

(Process 3)
Next, as step 3, as shown in FIG. 2 (c), the core portion-forming resin film is exposed through a photomask and then developed, and then the optical waveguide core pattern (core portion 2) is formed. Form. Specifically, actinic rays are irradiated in an image form through a photomask 6 having a negative or positive mask pattern called an artwork. Alternatively, the active light beam may be directly irradiated on the image without passing through the photomask 6 by using laser direct drawing. 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, there are those that effectively radiate visible light such as a photographic flood bulb and a solar lamp.

Here, the irradiation amount of actinic rays is preferably 0.01 to 10 J / cm ² . When it is 0.01 J / cm ² or more, the curing reaction proceeds sufficiently, and the core portion 2 is not washed away by the development process described later, and when it is 10 J / cm ² or less, the core portion 2 is caused by excessive exposure. It is suitable for forming a fine pattern without being fat. From the above viewpoint, it is more preferably 0.05 to 5 J / cm ² , and further preferably 0.1 to 3 J / cm ² .

In addition, after exposure, you may perform post-exposure heating from a viewpoint of the resolution of the core part 2, and adhesive improvement. The time from ultraviolet irradiation to post-exposure heating is preferably within 10 minutes. Within 10 minutes, the active species generated by ultraviolet irradiation will not be deactivated. The post-exposure heating temperature is preferably 40 to 160 ° C., and the time is preferably 30 seconds to 10 minutes.

After the exposure, as shown in FIG. 2 (d), the base film of the core portion forming resin film 7 is removed, and development corresponding to the composition of the core portion forming resin film such as an alkaline aqueous solution or an aqueous developer is performed. Using the liquid, development is performed by a known method such as spraying, rocking dipping, brushing, scraping, dipping or paddle. Moreover, you may use together 2 or more types of image development methods as needed.

The base of the alkaline aqueous solution is not particularly limited. For example, alkali hydroxide such as lithium, sodium or potassium hydroxide; alkali carbonate such as lithium, sodium, potassium or ammonium carbonate or bicarbonate; Alkali metal phosphates such as potassium phosphate and sodium phosphate; Alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate; Sodium salts such as borax and sodium metasilicate; Tetramethylammonium hydroxide, Triethanolamine And organic bases such as ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1,3-propanediol, 1,3-diaminopropanol-2-morpholine, and the like. The pH of the alkaline aqueous solution used for development is preferably 9 to 11, and the temperature is adjusted in accordance with the developability of the core portion-forming resin composition layer. In the alkaline aqueous solution, a surfactant, an antifoaming agent, a small amount of an organic solvent for accelerating development, and the like may be mixed.

The aqueous developer is not particularly limited as long as it is composed of water or an alkaline aqueous solution and one or more organic solvents. The pH of the aqueous developer is preferably as low as possible within the range where the development of the core part-forming resin film can be sufficiently performed, more preferably from 8 to 12, and even more preferably from 9 to 10.
Examples of the organic solvent used in the aqueous developer include alcohols such as methanol, ethanol, isopropanol, butanol, ethylene glycol and propylene glycol; ketones such as acetone and 4-hydroxy-4-methyl-2-pentanone; ethylene glycol Examples thereof include polyhydric alcohol alkyl ethers such as monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether and diethylene glycol monobutyl ether. These can be used alone or in combination of two or more.

The concentration of the organic solvent in the aqueous developer is usually preferably 2 to 90% by mass.
The temperature of the aqueous developer is adjusted in accordance with the developability of the core portion forming resin composition. Further, a small amount of a surfactant, an antifoaming agent or the like may be mixed in the aqueous developer.

As the post-development processing, the core portion 2 of the optical waveguide may be cleaned using a cleaning liquid composed of water and the organic solvent as necessary. An organic solvent can be used individually or in combination of 2 or more types.

The concentration of the organic solvent in the cleaning liquid is usually preferably 2 to 90% by mass.
The temperature of the cleaning liquid is adjusted in accordance with the developability of the core portion forming resin composition.
As processing after development or washing, the core 2 may be further cured by heating at about 60 to 250 ° C. or exposure at about 0.1 to 1000 mJ / cm ² as necessary.

(Process 4)
Subsequently, as step 4, as shown in FIG. 2E, an upper clad layer forming resin film is laminated on the lower clad layer 4 and the core portion 2 in the same manner as in

steps

1 and 2. The upper cladding layer 3 is formed. Here, the upper clad layer forming resin film is designed to have a lower refractive index than the core portion forming resin film. Further, the thickness of the upper cladding layer 3 is preferably larger than the height of the core portion 2.
Next, the upper clad layer-forming resin film is cured by light or heat in the same manner as in step 1 to form the upper clad layer 3.
When the base film of the resin film for forming a clad layer is PET, the irradiation amount of active light is preferably 0.1 to 5 J / cm ² . On the other hand, when the base film is polyethylene naphthalate, polyamide, polyimide, polyamideimide, polyetherimide, polyphenylene ether, polyether sulfide, polyethersulfone, polysulfone, etc., actinic rays having a short wavelength such as ultraviolet rays are used compared to PET. Since it is difficult to pass through, the irradiation amount of actinic rays is preferably 0.5 to 30 J / cm ² . When it is 0.5 J / cm ² or more, the curing reaction proceeds sufficiently, and when it is 30 J / cm ² or less, the time of light irradiation does not take too long. From the above viewpoint, it is more preferably 3 to 27 J / cm ² , and further preferably 5 to 25 J / cm ² .

In addition, in order to make it harden | cure, the double-sided exposure machine which can irradiate actinic light simultaneously from both surfaces can be used. Moreover, you may irradiate actinic light, heating. The heating temperature during or after irradiation with actinic rays is preferably 50 to 200 ° C., but these conditions are not particularly limited.
After forming the upper cladding layer 3, the base film can be removed if necessary to produce the optical waveguide 1.

The optical waveguide of the present invention may be used as an optical transmission path of an optical module because it is excellent in transparency and light propagation. Examples of the optical module include an optical waveguide with an optical fiber in which optical fibers are connected to both ends of the optical waveguide, an optical waveguide with a connector in which connectors are connected to both ends of the optical waveguide, and an opto-electrical device in which the optical waveguide and the printed wiring board are combined. Examples include a composite substrate, an optical / electrical conversion module that combines an optical waveguide and an optical / electrical conversion element that mutually converts an optical signal and an electrical signal, and a wavelength multiplexer / demultiplexer that combines an optical waveguide and a wavelength division filter. In the photoelectric composite substrate, the printed wiring board to be combined is not particularly limited, and either a rigid substrate such as a glass epoxy substrate or a flexible substrate such as a polyimide substrate may be used.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited to these examples.
In addition, the physical property of the polymer obtained by the synthesis example was measured with the following method.

[Measurement of acid value]
The acid value was calculated from the amount of 0.1 mol / L potassium hydroxide aqueous solution required to neutralize the polymer solution obtained in the synthesis example. At this time, the point at which the phenolphthalein added as an indicator changed color from colorless to pink was defined as the neutralization point.

[Measurement of weight average molecular weight]
The weight average molecular weight (standard polystyrene conversion) was measured under the following conditions by gel permeation chromatography (GPC). The calibration curve was approximated by a cubic equation using a standard polystyrene 5 sample set (product number PStQuick B, manufactured by Tosoh Corporation).
Apparatus: “SD-8022” (Degasser), “DP-8020” (Pump), and “RI-8020” (Detector) (trade name, manufactured by Tosoh Corporation)
Column: Gelpack (registered trademark) GL-A150-S and Gelpack (registered trademark) GL-A160-S (two in total) (trade name, manufactured by Hitachi Chemical Co., Ltd.)
Eluent: Tetrahydrofuran Sample concentration: 0.5 mg / ml
Elution rate: 1 ml / min
Measurement temperature: 25 ° C
In addition, unless otherwise indicated, the molecular weight measurement in a present Example was performed on the same conditions as the above.

Synthesis Example 1 [Base polymer for forming core and clad layer; Preparation of (meth) acrylic polymer (P-1)]
In a flask equipped with a stirrer, a cooling pipe, a gas introduction pipe, a dropping funnel and a thermometer, 42 parts by mass of propylene glycol monomethyl ether acetate and 21 parts by mass of methyl lactate were weighed and stirred while introducing nitrogen gas. The liquid temperature was raised to 65 ° C., 14.5 parts by mass of N-cyclohexylmaleimide, 20 parts by mass of benzyl acrylate, 39 parts by mass of o-phenylphenol 1.5EO acrylate, 14 parts by mass of 2-hydroxyethyl methacrylate, 12. A mixture of 5 parts by mass, 4 parts by mass of 2,2′-azobis (2,4-dimethylvaleronitrile), 37 parts by mass of propylene glycol monomethyl ether acetate, and 21 parts by mass of methyl lactate was added dropwise over 3 hours, and then 65 ° C. The mixture was further stirred at 95 ° C. for 1 hour to obtain a (meth) acrylic polymer (P-1) solution (solid content: 45% by mass).
Hereinafter, the (meth) acrylic polymer (P-1) solution is also referred to as “P-1 solution”.
The acid value of the obtained (meth) acrylic polymer (P-1) was 79 mgKOH / g, and the weight average molecular weight (in terms of standard polystyrene) of P-1 was 3.9 × 10 ⁴ .

Production Example 1 [Preparation of core part-forming resin varnish COV-1]
60 parts by mass of the P-1 solution (solid content: 45% by mass), bisphenol A type epoxy acrylate (“EA-1010N” manufactured by Shin-Nakamura Chemical Co., Ltd.) (epoxy equivalent 518 g / eq) as a polymerizable compound, As a polymerization initiator, 1 part by weight of 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one (“Irgacure 2959” manufactured by BASF Japan Ltd.), bis ( 1 part by weight of 2,4,6-trimethylbenzoyl) phenylphosphine oxide (“Irgacure 819” manufactured by BASF Japan Ltd.) was weighed into a wide-mouthed plastic bottle, and was stirred at a temperature of 25 ° C. and a rotational speed of 400 min ^−1. Then, the solution was prepared by stirring for 6 hours.
The obtained solution was subjected to a temperature of 25 ° C. and a pressure of 0 ° C. using a polyflon filter having a pore size of 2 μm (“PF020” manufactured by Advantech Toyo Co., Ltd.) and a membrane filter having a pore size of 0.5 μm (“J050A” manufactured by Advantech Toyo Co., Ltd.). Pressure filtration was performed under the condition of 4 MPa.
Subsequently, vacuum degassing was performed for 15 minutes under the condition of a reduced pressure of 50 mmHg using a vacuum pump and a bell jar to obtain a core part forming resin varnish COV-1.

Production Example 2 [Production of Core Part Forming Resin Film COF-1]
Using a coating machine (Multicoater TM-MC manufactured by Hirano Techseed Co., Ltd.) on the non-treated surface of the PET film (“Cosmo Shine A1517” manufactured by Toyobo Co., Ltd., thickness 16 μm). And then dried at 100 ° C. for 20 minutes, and then a release PET film (“Purex A31” manufactured by Teijin DuPont Films Ltd., thickness 25 μm) is pasted as a protective film to obtain a core part-forming resin film COF-1. It was. At this time, the thickness of the resin layer can be arbitrarily adjusted by adjusting the gap of the coating machine, but in this production example, the thickness after curing was adjusted to 50 μm.

Example 1 [Preparation of resin varnish CLV-1 for forming cladding layer]
As component (A), 111 parts by mass of the P-1 solution (solid content: 45% by mass) (solid content: 50 parts by mass), and as component (B1), urethane (meth) acrylate having a carboxy group (manufactured by Hitachi Chemical Co., Ltd.) "Hitaroid 9082-95") 20 parts by mass, 5 parts by mass of isocyanurate type urethane (meth) acrylate ("UA-21" manufactured by Shin-Nakamura Chemical Co., Ltd.) having three methacryloyloxyalkyl groups, EO (ethylene oxide) modified isocyania 10 parts by weight of a nurate type triacrylate (“Fancryl FA-731A” manufactured by Hitachi Chemical Co., Ltd.) and a bisphenol A type epoxy acrylate represented by the following formula as the component (B2) (“EA-1010N manufactured by Shin-Nakamura Chemical Co., Ltd.) ]) (Epoxy equivalent 518 g / eq) 15 parts by mass, (C) 1- [ -(2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one (“Irgacure 2959” manufactured by BASF Japan Ltd.), 1 part by weight, bis (2,4,6-trimethylbenzoyl) ) 1 part by mass of phenylphosphine oxide (“Irgacure 819” manufactured by BASF Japan Ltd.) and 23 parts by mass of propylene glycol monomethyl ether acetate as an organic solvent for dilution were mixed.
The obtained solution was subjected to pressure filtration using a polyflon filter having a pore diameter of 2 μm (“PF020” manufactured by Advantech Toyo Co., Ltd.) and then degassed under reduced pressure to obtain a resin varnish CLV-1 for forming a cladding layer.

[Preparation of Cladding Layer Forming Resin Film CLF-1]
Clad layer forming resin varnish CLV-1 obtained above was used on the non-treated surface of a PET film (“Cosmo Shine A4100” manufactured by Toyobo Co., Ltd., thickness 50 μm) as a base film. After coating at 100 ° C. for 20 minutes, a surface release treated PET film (“Purex A31” manufactured by Teijin DuPont Films Ltd., thickness 25 μm) is pasted as a protective film, and a resin film CLF-1 for forming a clad layer is applied. Obtained.
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 film thickness after curing is 20 μm for the resin film for forming the lower cladding layer, and the upper cladding. It adjusted so that it might be set to 60 micrometers with the resin film for layer formation. In addition, it adjusted so that it might be set to 50 micrometers about the film for light transmittance measurement and the film for toughness evaluation in wavelength 850nm mentioned later.

[Measurement of light transmittance at a wavelength of 850 nm]
The clad layer forming resin film CLF-1 from which the protective film (Purex A31) has been removed is subjected to a pressure of 0.4 MPa, using a vacuum laminator on a slide glass (size: 76 mm × 26 mm, thickness: 1 mm), Lamination was performed under conditions of a temperature of 50 ° C. and a pressurization time of 30 seconds. Next, ultraviolet light (wavelength 365 nm) was irradiated at 1000 mJ / cm ² with an ultraviolet exposure machine (Dainippon Screen Co., Ltd. “MAP-1200-L”), and further heated at 160 ° C. for 1 hour to measure light transmittance. A sample was made. The light transmittance of this sample at a wavelength of 850 nm was measured using a spectrophotometer (“U-3310” manufactured by Hitachi High-Technologies Corporation).

[Toughness evaluation]
The clad layer-forming resin film CLF-1 from which the protective film (Purex A31) has been removed is pressure-treated using the vacuum laminator on a polyimide film (Kapton 200EN) (size: 80 mm × 26 mm, thickness: 1 mm). Lamination was performed under the conditions of 0.4 MPa, a temperature of 50 ° C., and a pressing time of 30 seconds. Next, ultraviolet rays (wavelength 365 nm) were irradiated at 1000 mJ / cm ² with the ultraviolet exposure machine, and further heated at 160 ° C. for 1 hour, to prepare samples for toughness evaluation. The toughness of this sample was evaluated according to the following criteria by winding it around a rod with a radius of 1 mm.
(Evaluation criteria)
A: No change B ... Crack generation or breakage was observed

[Optical Waveguide Manufacturing Method]
(Process 1)
Using a vacuum pressure laminator (“MVLP-500 / 600” manufactured by Meiki Seisakusho Co., Ltd.), the protective film (Purex A31) was removed under the conditions of a pressure of 0.4 MPa, a temperature of 80 ° C., and a pressurization time of 30 seconds. The lower clad layer forming resin film CLF-1 was laminated on a glass epoxy resin substrate (“MCL-E-679FB” manufactured by Hitachi Chemical Co., Ltd., plate thickness 0.6 mm, copper foil removed by etching). Next, using an ultraviolet exposure machine (“MAP-1200-L” manufactured by Dainippon Screen Co., Ltd.), after irradiating the ultraviolet rays (wavelength 365 nm) with 4000 mJ / cm ² , the support film (Cosmo Shine A4100) is removed and 120 ° C. The lower clad layer 4 was formed by heat treatment for 1 hour.

(Process 2)
Subsequently, the core part-forming resin film COF-1 from which the protective film (Purex A31) has been removed using a roll laminator (“HLM-1500” manufactured by Hitachi Chemical Technoplant Co., Ltd.) is formed on the lower clad layer 4. And a pressure of 0.5 MPa, a temperature of 50 ° C., and a speed of 0.2 m / min.

(Process 3)
Next, the resin film for forming a core part (core pattern) is exposed by irradiating 2500 mJ / cm ² of ultraviolet rays (wavelength 365 nm) with the ultraviolet exposure machine through a negative photomask having an optical waveguide forming pattern having a width of 50 μm. did. After removing the support film (Cosmo Shine A1517), using a spray-type developing device (“RX-40D” manufactured by Yamazaki Kikai Co., Ltd.), a 1 mass% sodium carbonate aqueous solution at a temperature of 30 ° C., a spray pressure of 0.15 MPa, development Development was performed under conditions of 105 seconds. Subsequently, the core part 2 was formed after washing with pure water, heat drying and thermosetting at 160 ° C. for 1 hour.

(Process 4)
Next, the upper clad layer-forming resin film CLF-1 from which the protective film (Purex A31) has been removed using the vacuum pressurizing laminator is applied to the core 2 and the lower clad layer 4 at a pressure of 0.4 MPa and a temperature. Lamination was performed at 80 ° C. and a pressurization time of 30 seconds. After irradiating with ultraviolet light (wavelength 365 nm) 4000 mJ / cm ² and removing the support film (Cosmo Shine A4100), the upper clad layer 3 is formed by heating and curing at 160 ° C. for 1 hour, as shown in FIG. The optical waveguide 1 shown was obtained. Thereafter, a rigid optical waveguide having a length of 10 cm was cut out using a dicing saw (“DAD-341” manufactured by DISCO Corporation).

[Measurement of optical loss]
The optical propagation loss of the obtained optical waveguide is determined based on the VCSEL (“FLS-300-01-VCL” manufactured by EXFO) having a wavelength of 850 nm as the light source, the light receiving sensor (“Q82214” manufactured by Advantest Corporation), and the incident fiber. (GI-50 / 125 multimode fiber, NA = 0.20), and output fiber (SI-114 / 125, NA = 0.22). The optical propagation loss was calculated by dividing the optical loss measurement value (dB) by the optical waveguide length (10 cm), and was used as the optical loss amount (initial).

[Environmental reliability evaluation-End face evaluation]
The environmental reliability of the end face of the optical waveguide was evaluated by a high temperature and high humidity standing test.
The obtained optical waveguide was heated at a temperature of 85 ° C. and a humidity of 85% under the conditions in accordance with the JPCA standard (JPCA-PE02-05-01S) using a high temperature and high humidity tester (“PL-2KT” manufactured by ESPEC Corporation). The high temperature and high humidity standing test was conducted for 1000 hours.
The obtained optical waveguide is cut into a length of 2 mm in a direction perpendicular to the core pattern direction using a dicing saw (“DAD-341” manufactured by DISCO Corporation), and the obtained end face is observed, thereby providing environmental reliability. The following criteria were used to evaluate whether or not
(Evaluation criteria)
A: No precipitate such as bleed-out component on the end face B: Precipitate such as bleed-out component on the end face

[Environmental reliability evaluation-Light loss]
The environmental reliability related to light loss was evaluated by a high temperature and high humidity standing test.
The light propagation loss of the optical waveguide after the high-temperature and high-humidity test is measured as the amount of light loss (after the test) obtained by using the same light source, light-receiving element, incident fiber, and output fiber as described above. The amount of increase in light loss due to the damp test was calculated according to the following formula and evaluated according to the following criteria.
[Amount of increase in optical loss] = [Amount of optical loss (after test)]-[Amount of optical loss (initial)]
(Evaluation criteria)
A: Increase in optical loss is 0.05 dB / cm or less B: Exceeds 0.05 dB / cm

Examples 2 and 3 and Comparative Examples 1 and 2
According to the composition shown in Table 1, clad layer forming resin varnishes CLV-2 to 5 were prepared, and clad layer forming resin films CLF-2 to 5 were produced in the same manner as in Example 1.
Thereafter, an optical waveguide was produced in the same manner as in Example 1.

The evaluation results of Examples 1 to 3 and Comparative Examples 1 and 2 are shown in Table 1, and the cross sections of the optical waveguides after the high-temperature and high-humidity test of Examples 2 and 1 are shown in FIGS. 3 (a) and 3 (b).

Details of each component shown in Table 1 are shown below.
[(A) component]
P-1: (Meth) acrylic polymer (P-1) prepared in Synthesis Example 1 (weight average molecular weight: 3.5 × 10 ⁴ , acid value: 80 mgKOH / g)

[Component (B)]
[(B1) component]
FA-731A: Tris (2-acryloyloxyethyl) isocyanurate (manufactured by Hitachi Chemical Co., Ltd., trade name: funcryl FA-731A, molecular weight 423)
HT9082-95: Urethane acrylate having two carboxy groups (manufactured by Hitachi Chemical Co., Ltd., trade name: Hitaroid HT9082-95 (compound having acryloyloxymethyl groups via cyclohexyl groups at both ends), weight average molecular weight 4,000 , Acid value 22mgKOH / g)
UA-21: Tris (methacryloyloxytetraethylene glycol isocyanate hexamethylene) isocyanurate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: UA-21, weight average molecular weight 1290)
[(B2) component]
EA-1010N: acrylic acid modified bisphenol A type epoxy monoacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: EA-1010N, epoxy equivalent: 518 g / eq)
[(B ′) component]
YX-8034: Bisphenol A type hydrogenated alicyclic epoxy resin (Mitsubishi Chemical Corporation grade: YX-8034)
BL3175: Polyfunctional block isocyanate solution in which isocyanurate type trimer of hexamethylene diisocyanate is protected with methyl ethyl ketone oxime (solid content: 75% by mass) (manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Sumijoule BL3175)

[Component (C)]
I-2959: 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one (manufactured by BASF Japan, trade name: Irgacure (registered trademark) 2959)
I-819: Bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (manufactured by BASF Japan Ltd., trade name: Irgacure (registered trademark) 819)

From Table 1, the optical waveguide-forming film obtained using the optical waveguide-forming resin composition of the present invention is excellent in transparency and toughness, and the optical waveguide produced using this has a low optical loss amount, It turns out that it is excellent in environmental reliability and toughness by a high temperature and high humidity leaving test. On the other hand, it can be seen that the optical waveguide manufactured using the resin composition for forming an optical waveguide which does not belong to the present invention shown in Comparative Examples 1 and 2 has a high light loss and is inferior in environmental reliability.

The resin composition for forming an optical waveguide and the resin film for forming an optical waveguide of the present invention are excellent in transparency (low light propagation loss) and toughness, and an optical waveguide produced using these has excellent transparency and toughness. Are better. Furthermore, no deterioration of light loss was observed after the reliability test by the high temperature and high humidity leaving test, and the environmental reliability was excellent.
Therefore, the optical waveguide resin composition of the present invention is suitable as a resin composition for forming an optical waveguide used for optical interconnection or the like.

DESCRIPTION OF SYMBOLS 1 Optical waveguide 2 Core part 3 Upper clad layer 4 Lower clad layer 5 Base material or base film 6 Photomask 7 Core part formation resin film

Claims

(A) a resin composition for forming an optical waveguide containing a polymer having an alkali-soluble group, (B) a compound having an ethylenically unsaturated group in the molecule, and (C) a polymerization initiator,
The component (B) is at least one compound selected from the following (B1-1) to (B1-3) as the component (B1) and the alkali-soluble group of the component (A) in the molecule as the component (B2) A resin composition for forming an optical waveguide, comprising a group that reacts with a compound and a compound having an ethylenically unsaturated group.
(B1-1) Compound having three or more ethylenically unsaturated groups (B1-2) Compound having carboxy group and two or more ethylenically unsaturated groups (B1-3) Urethane bond and one or more ethylene Compound having an unsaturated group
The resin composition for forming an optical waveguide according to claim 1, wherein the component (B1-1) is a compound further having an isocyanurate ring in the molecule.
The resin composition for forming an optical waveguide according to claim 1 or 2, wherein the component (B1-1) is a mixture of two or more compounds having different molecular weights.
The component (B1-2) is a compound having two or more carboxy groups in the molecular chain and one or more ethylenically unsaturated groups at the molecular chain terminals. Item 6. A resin composition for forming an optical waveguide according to Item.
The component (B1-2) is a compound further having a urethane bond and at least one ring structure selected from an alicyclic structure, an aromatic ring structure and a heterocyclic structure in the molecule. The resin composition for forming an optical waveguide according to any one of the above items.
The component (B1-3) is a compound having at least one ring structure selected from an alicyclic structure, an aromatic ring structure and a heterocyclic structure in the molecule. The resin composition for optical waveguide formation as described.
The resin composition for forming an optical waveguide according to any one of claims 1 to 6, wherein the component (B1-3) comprises a compound having a urethane bond and three or more ethylenically unsaturated groups.
The light guide according to any one of claims 1 to 7, wherein the component (B2) is a compound having (B2-1) one or more epoxy groups and one or more ethylenically unsaturated groups in the molecule. A resin composition for forming a waveguide.
The resin composition for forming an optical waveguide according to claim 8, wherein the component (B2-1) is a compound further having an alicyclic structure or an aromatic ring structure in the molecule.
The resin composition for forming an optical waveguide according to claim 8 or 9, wherein the component (B2-1) is a compound further having a bisphenol skeleton in the molecule.
The resin composition for forming an optical waveguide according to any one of claims 1 to 10, wherein the component (A) is a polymer having a weight average molecular weight of 6,000 to 300,000.
The resin composition for forming an optical waveguide according to any one of claims 1 to 11, wherein the component (A) is a polymer having a maleimide skeleton in the main chain.
The content of component (A) is 10 to 85% by mass relative to the total amount of components (A) and (B), and the content of component (B) is relative to the total amount of components (A) and (B). 15 to 90% by mass, the mass ratio [(B1) / (B2)] of the component (B1) to the component (B2) is 50/50 to 85/15, and the content of the component (C) is (A The resin composition for forming an optical waveguide according to any one of claims 1 to 12, which is 0.01 to 10 parts by mass with respect to 100 parts by mass of the total amount of the components (B) and (B).
An optical waveguide in which at least one of a lower cladding layer, a core portion, and an upper cladding layer is formed using the resin composition for forming an optical waveguide according to any one of claims 1 to 13.
An optical waveguide forming resin film having a resin layer obtained by using the optical waveguide forming resin composition according to any one of claims 1 to 13.
An optical waveguide in which at least one of a lower clad layer, a core portion, and an upper clad layer is formed using the optical waveguide forming resin film according to claim 15.
The optical waveguide according to claim 14 or 16, wherein a light propagation loss at a wavelength of 850 nm is 0.25 dB / cm or less.
An optical waveguide manufacturing method including the following steps 1 to 4, wherein at least one of a lower cladding layer, a core portion, and an upper cladding layer is formed using the resin film for forming an optical waveguide according to claim 15; Manufacturing method of optical waveguide.
Step 1: A step of laminating a resin film for forming a lower clad layer on a substrate to form a lower clad layer Step 2: A step of laminating a resin film for forming a core portion on the lower clad layer Step 3: The core portion Step of forming the core part after exposing the forming resin film through a photomask and then developing Step 4: The upper clad layer-forming resin film is laminated on the lower clad layer and the core part. Step of forming the cladding layer