Resin compositions, dry films, optical waveguides, optoelectronic composite substrates, and electronic components

Abstract

The present invention provides a resin composition capable of suppressing warping of laminates, which are intermediates in the manufacturing process of optical waveguides. [Solution] A resin composition that can be used in the core layer of an optical waveguide, wherein the storage modulus E' of a cured product made from the resin composition, calculated by a predetermined method, is 100 MPa or more and 1000 MPa or less at 30°C.

Description

[Technical Field]

[0001] This invention relates to resin compositions, dry films, optical waveguides, optoelectronic composite substrates, and electronic components. [Background technology]

[0002] In recent years, there has been a growing demand for components in information and communication equipment that can achieve more advanced information communication, such as increased data capacity and higher communication speeds. Optical waveguides are being considered as one such component. Examples of optical waveguide technologies include the technology described in Patent Document 1.

[0003] Patent Document 1 describes a photosensitive resin composition comprising (A) a cyclic olefin resin, (B) at least one of a monomer having a cyclic ether group and an oligomer having a cyclic ether group, which has a refractive index different from (A), and (C) a photoacid generator. Patent Document 1 describes a photosensitive resin composition that can suppress the occurrence of light propagation loss. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2011-184692 [Overview of the project] [Problems that the invention aims to solve]

[0005] The present invention provides a resin composition capable of suppressing warping of laminates, which are intermediates in the manufacturing process of optical waveguides. [Means for solving the problem]

[0006] According to the present invention, the following resin compositions, dry films, optical waveguides, optoelectronic composite substrates, and electronic components are provided.

[0007] [1] A resin composition that can be used in the core layer of an optical waveguide, A resin composition having a storage modulus E' at 30°C of a cured product made from the resin composition calculated by the method described below, which is 100 MPa or more and 1000 MPa or less. [method] Integrated light intensity of 120 mJ / cm² under atmospheric conditions 2 After irradiating with light under the specified conditions, a cured product made of the resin composition with a thickness of 40 μm is heated in an atmospheric environment at 60°C for 4 hours. Using a dynamic viscoelasticity measuring device, the product is heated from 30°C to 300°C in an atmospheric environment at a frequency of 1 Hz, in tensile mode, with a sample distance of 2 cm, a sample width of 1 cm, and a heating rate of 5°C / min. The storage modulus E' and loss modulus E'' with respect to temperature are measured, and the storage modulus E' at 30°C and loss modulus E'' at 30°C of the cured product made of the resin composition are calculated. [2] The resin composition according to [1], wherein the loss modulus E'' of the cured product made from the resin composition calculated by the above method is 10 MPa or more and 200 MPa or less at 30°C. [3] The resin composition according to [1] or [2], comprising a resin (A) having a norbornene skeleton and a compound (B) having a cyclic ether structure. [4] The resin composition according to [3], wherein the content of the compound (B) having the cyclic ether structure in the resin composition is 21 parts by mass or more and 100 parts by mass or less, when the content of the resin (A) having the norbornene skeleton in the resin composition is 100 parts by mass. [5] The resin composition according to [3] or [4], wherein the compound (B) having the cyclic ether structure comprises at least one selected from the group consisting of oxetane compounds (B1) and epoxy compounds (B2). [6] The compound (B) having the cyclic ether structure includes an oxetane compound (B1), The resin composition according to any one of [3] to [5], wherein the oxetane compound (B1) contains a monofunctional oxetane compound. [7] The resin composition according to any one of [3] to [6], wherein the resin (A) having a norbornene skeleton contains a resin having an aromatic ring. [8] The resin composition according to any one of [3] to [7], further comprising a photosensitizer (C). [9] The resin composition according to any one of [1] to [8], having a refractive index of 1.51 or more and 1.60 or less.

[10] A dry film comprising a resin layer made of the resin composition according to any one of [1] to [9].

[11] The dry film according to

[10] , wherein the light transmittance of the resin layer at a wavelength of 850 nm is 85% or more.

[12] An optical waveguide comprising a core layer and a cladding layer, The optical waveguide, wherein the core layer is a layer containing the resin composition according to any one of [1] to [9].

[13] A substrate, An optoelectronic composite substrate comprising the optical waveguide according to

[12] provided on the substrate.

[14] An electronic component comprising the optoelectronic composite substrate according to

[13] . [Effect of the Invention]

[0008] According to the present invention, it is possible to provide a resin composition capable of suppressing the warpage of a laminate, which is an intermediate in the manufacturing process of an optical waveguide. [Brief Description of the Drawings]

[0009] [Figure 1] It is a cross-sectional view schematically showing an example of the structure of the optoelectronic composite substrate of the present embodiment. [Mode for Carrying Out the Invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. Note that the drawings are simplified diagrams and do not correspond to the actual dimensional ratios. Unless otherwise specified, the numerical range "A to B" represents A or greater and B or less. In this specification, (meth)acrylic resin is a concept that includes both acrylic resin and methacrylic resin.

[0011] One method for manufacturing an optical waveguide is to sequentially laminate dry films to form each layer that constitutes the optical waveguide. In the inventors' research, it was found that in such a method for manufacturing an optical waveguide, warping may occur in the intermediate laminate.

[0012] Specifically, the inventors have found that warping is likely to occur in laminates having a layer structure of "substrate / first cladding resin layer / core forming resin layer". The inventors focused on the resin composition constituting the core-forming resin layer in order to suppress the warping of the above-mentioned laminate. Furthermore, as a result of diligent research by the inventors, they found that the warping of the above-mentioned laminate can be suppressed by setting the storage modulus E' of the cured product made of the resin composition cured under specific conditions to a specific numerical range at 30°C.

[0013] [Resin composition] The resin composition of this embodiment is a resin composition that can be used in the core layer of an optical waveguide, and the storage modulus E' of the cured product made of the resin composition at 30°C is 100 MPa or more and 1000 MPa or less. The storage modulus E' at 30°C of the cured product made from the resin composition of this embodiment is preferably 120 MPa or more, more preferably 140 MPa or more, even more preferably 160 MPa or more, and even more preferably 180 MPa or more. Furthermore, from the viewpoint of further suppressing warping of the laminate, it is preferably 900 MPa or less, more preferably 800 MPa or less, even more preferably 750 MPa or less, and even more preferably 700 MPa or less. Also, from the viewpoint of further suppressing warping of the laminate, the storage modulus E' at 30°C of the cured product made from the resin composition of this embodiment is preferably 120 MPa or more and 900 MPa or less, more preferably 140 MPa or more and 800 MPa or less, even more preferably 160 MPa or more and 750 MPa or even more preferably 180 MPa or more and 700 MPa or less.

[0014] The storage modulus E' of a cured product made from a resin composition at 30°C can be set to a desired value by, for example, adjusting the types and content of components contained in the resin composition. Specifically, the desired value can be achieved by ensuring the resin composition contains a resin and a low-molecular-weight compound, the resin contains a resin having a norbornene skeleton, the low-molecular-weight compound contains a compound having a cyclic ether structure, and adjusting the content of the low-molecular-weight compound relative to the resin content in the resin composition.

[0015] The loss modulus E'' of the cured product made from the resin composition of this embodiment at 30°C is preferably 10 MPa to 200 MPa, more preferably 15 MPa to 180 MPa, and even more preferably 25 MPa to 160 MPa.

[0016] In this specification, the storage modulus E' and loss modulus E'' of a cured resin composition at 30°C refer to the values ​​calculated by the following [Method].

[0017] [method] Integrated light intensity of 120 mJ / cm² under atmospheric conditions 2A cured resin composition with a thickness of 40 μm, which was cured by light irradiation under the specified conditions and then heated at 60°C for 4 hours in an atmospheric environment, was heated from 30°C to 300°C using a dynamic viscoelasticity analyzer under the conditions of atmospheric environment, frequency of 1 Hz, tensile mode, sample distance of 2 cm, sample width of 1 cm, and heating rate of 5°C / min. The storage modulus E' and loss modulus E'' with respect to temperature were measured, and the storage modulus E' at 30°C and loss modulus E'' at 30°C of the cured resin composition were calculated.

[0018] The inventors of the present invention have for the first time discovered that when a cured product obtained by curing a sample under the conditions described in the above [Method] is used as the measurement sample, the value of the storage modulus E' at 30°C correlates with the warping of the laminate. In other words, the present invention is not only important in setting the storage modulus E' at 30°C of a cured product made of a resin composition within a specific numerical range, but also in setting the curing conditions of the measurement sample within a specific range.

[0019] The refractive index of the resin composition of this embodiment is preferably 1.51 or higher, more preferably 1.52 or higher, and even more preferably 1.53 or higher, from the viewpoint of further improving the optical propagation efficiency of the optical waveguide, and the upper limit is not particularly limited, but may be, for example, 1.60 or lower, or 1.59 or lower. Furthermore, the refractive index of the resin composition of this embodiment is preferably 1.51 or higher and 1.60 or lower, more preferably 1.52 or higher and 1.60 or lower, and even more preferably 1.53 or higher and 1.59 or lower, from the viewpoint of further improving the optical propagation efficiency of the optical waveguide. The refractive index of a resin composition refers to the refractive index measured for a resin film made of the resin composition using an Abbe refractometer under conditions of 23°C and 589 nm. A resin film made of a resin composition can be produced, for example, by coating and drying the resin composition on a substrate film, as described in the examples.

[0020] The light transmittance of the resin composition of this embodiment for a wavelength of 850 nm is preferably 85% to 100%, more preferably 90% to 100%, more preferably 95% to 100%, more preferably 97% to 100%, and more preferably 98% to 100%, from the viewpoint of further improving the light propagation efficiency of the optical waveguide. The light transmittance of a resin composition at a wavelength of 850 nm refers to the value of the light transmittance measured by an ultraviolet-visible spectrophotometer for a resin film made of a resin composition with a thickness of 40 μm. A resin film consisting of a resin composition with a thickness of 40 μm can be produced, for example, by coating and drying the resin composition on a substrate film, as described in the examples.

[0021] The shape of the resin composition in this embodiment is not particularly limited and may include, for example, a film, a membrane, a varnish, a sheet, or the like.

[0022] The resin composition of this embodiment contains a resin. The resin includes, for example, at least one selected from the group consisting of resins having a norbornene skeleton, polyimide resins, epoxy resins, and (meth)acrylic resins, and preferably includes a resin having a norbornene skeleton.

[0023] The resin composition of this embodiment preferably contains a low molecular weight compound. The low molecular weight compounds preferably include compounds having a cyclic ether structure.

[0024] The resin composition of this embodiment preferably comprises a resin and a low molecular weight compound, more preferably a resin having a norbornene skeleton (A) and a compound having a cyclic ether structure (B), and even more preferably a resin having a norbornene skeleton (A), a compound having a cyclic ether structure (B), and a photosensitive agent (C).

[0025] The preferred components of the resin composition of this embodiment will be described in detail below.

[0026] <Resin having a norbornene skeleton (A)> The resin composition of this embodiment preferably includes a resin (A) having a norbornene skeleton. The resin (A) having a norbornene skeleton is not particularly limited as long as it is a resin having a norbornene skeleton, and may be a homopolymer of a norbornene compound, a copolymer of a norbornene compound, or a copolymer of a norbornene compound and other compounds.

[0027] The resin (A) having a norbornene skeleton preferably includes a resin having an aromatic ring, from the viewpoint of adjusting the refractive index to a more appropriate range. The resin having an aromatic ring is preferably a resin containing a phenyl group.

[0028] The norbornene skeleton resin (A) preferably comprises a resin containing at least one structural unit selected from the group consisting of resins containing the structural unit represented by formula (1) and the structural unit represented by formula (2), and more preferably comprises a resin containing the structural unit represented by formula (1) and the structural unit represented by formula (2).

[0029] [ka]

[0030] In equation (1), a represents an integer between 0 and 15, inclusive. In formula (1), a is preferably an integer between 1 and 12, more preferably an integer between 2 and 10, and even more preferably an integer between 3 and 7.

[0031] [ka]

[0032] In equation (2), b represents an integer between 1 and 6, and R 21 , R 22 and R 23each independently represents any one selected from the group consisting of an aryl group and an alkyl group having 1 to 6 carbon atoms, and R 21 、R 22 and R 23 at least one selected from the group consisting of is an aryl group.

[0033] In formula (2), b preferably represents an integer of 1 or more and 4 or less, more preferably represents 1 or 2, and still more preferably represents 1.

[0034] In formula (2), R 21 、R 22 and R 23 in, the aryl group is a group selected from the group consisting of, for example, a phenyl group, a tolyl group, a naphthyl group, an anthracenyl group, etc., and is preferably a phenyl group. In formula (2), R 21 、R 22 and R 23 in, the alkyl group having 1 to 6 carbon atoms is preferably an alkyl group having 1 to 4 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and still more preferably a methyl group or an ethyl group. The alkyl group having 1 to 6 carbon atoms may be a straight-chain alkyl group or a branched alkyl group.

[0035] In formula (2), b represents 1 or 2, R 21 and R 22 each independently represent an aryl group, R 23 preferably represents an alkyl group having 1 to 6 carbon atoms, b represents 1 or 2, R 21 and R 22 represent a phenyl group, R 23 more preferably represents an alkyl group having 1 to 3 carbon atoms, b represents 1, R 21 and R 22 represent a phenyl group, R 23 more preferably represents a methyl group.

[0036] The refractive index of the resin (A) having a norbornene skeleton is preferably 1.53 or higher, more preferably 1.54 or higher, from the viewpoint of further improving the optical propagation efficiency of the optical waveguide, and the upper limit is not particularly limited, but may be, for example, 1.60 or lower, or 1.58 or lower. Furthermore, the refractive index of the resin (A) having a norbornene skeleton is preferably 1.53 or higher and 1.60 or lower, more preferably 1.54 or higher and 1.58 or lower, from the viewpoint of further improving the optical propagation efficiency of the optical waveguide. The refractive index of resin (A) having a norbornene skeleton refers to the refractive index measured with an Abbe refractometer under conditions of 23°C and 589 nm.

[0037] The weight-average molecular weight (Mw) of the resin (A) having a norbornene skeleton is preferably 10,000 to 300,000, more preferably 30,000 to 250,000, and even more preferably 50,000 to 200,000. The weight-average molecular weight (Mw) of resin (A) having a norbornene skeleton can be determined by gel permeation chromatography (GPC) using polystyrene as a standard substance.

[0038] The content of the norbornene skeleton resin (A) in the resin composition of this embodiment is preferably 50% to 85% by mass, more preferably 60% to 80% by mass, and even more preferably 65% ​​to 75% by mass, when the total amount of nonvolatile components in the resin composition is 100% by mass.

[0039] A resin (A) having a norbornene skeleton can be produced, for example, by known methods, and more specifically, by polymerizing monomers capable of forming each structural unit in any way.

[0040] The resin (A) having a norbornene skeleton may be a resin having one type of norbornene skeleton, or it may contain two or more types of resins having two or more types of norbornene skeletons.

[0041] <Compound having a cyclic ether structure (B)> The resin composition of this embodiment preferably contains compound (B) having a cyclic ether structure. In this specification, compound (B) having a cyclic ether structure means a low molecular weight compound, for example, a compound with a molecular weight of 1000 or less.

[0042] The compound (B) having a cyclic ether structure preferably includes at least one selected from the group consisting of oxetane compounds (B1) and epoxy compounds (B2).

[0043] The compound (B) having a cyclic ether structure may include a compound that is liquid at 23°C or a compound that is solid at 23°C, but from the viewpoint of further improving the coating properties of the resin composition, it is preferable to include a compound that is liquid at 23°C.

[0044] (Oxetane compound (B1)) The compound (B) having a cyclic ether structure preferably includes an oxetane compound (B1). The oxetane compound (B1) preferably includes an aliphatic oxetane compound.

[0045] Hereinafter, a polyfunctional oxetane compound refers to a compound containing two or more oxetanyl groups, and a monofunctional oxetane compound refers to a compound containing one oxetanyl group.

[0046] The oxetane compound (B1) preferably includes a monofunctional oxetane compound. The monofunctional oxetane compounds preferably include aliphatic monofunctional oxetane compounds.

[0047] The content of the monofunctional oxetane compound in compound (B) having a cyclic ether structure is preferably 70 parts by mass or more and 99 parts by mass or less, more preferably 73 parts by mass or more and 97 parts by mass or less, and even more preferably 77 parts by mass or more and 95 parts by mass or less, when the content of compound (B) having a cyclic ether structure in the resin composition is 100 parts by mass.

[0048] The content of the monofunctional oxetane compound in the oxetane compound (B1) is preferably 85 parts by mass or more and 100 parts by mass or less, more preferably 90 parts by mass or more and 100 parts by mass or less, even more preferably 95 parts by mass or more and 100 parts by mass or less, and even more preferably 98 parts by mass or more and 100 parts by mass or less, when the total content of the oxetane compound (B1) in the resin composition is 100 parts by mass.

[0049] The refractive index of the oxetane compound (B1) is preferably 1.41 or higher, more preferably 1.42 or higher, and even more preferably 1.43 or higher, from the viewpoint of further improving the optical propagation efficiency of the optical waveguide. The upper limit is not particularly limited, but may be, for example, 1.50 or lower, 1.49 or lower, or 1.48 or lower. Furthermore, the refractive index of the oxetane compound (B1) is preferably 1.41 or higher and 1.50 or lower, more preferably 1.42 or higher and 1.49 or lower, and even more preferably 1.43 or higher and 1.48 or lower, from the viewpoint of further improving the optical propagation efficiency of the optical waveguide. The refractive index of the oxetane compound (B1) refers to the refractive index measured at 23°C and 589 nm using an Abbe refractometer.

[0050] (Epoxy compound (B2)) The compound (B) having a cyclic ether structure preferably includes an epoxy compound (B2).

[0051] Hereinafter, a polyfunctional epoxy compound refers to a compound containing two or more epoxy groups, and a monofunctional epoxy compound refers to a compound containing one epoxy group.

[0052] The epoxy compound (B2) preferably includes a compound having an alicyclic structure within its molecule. Here, the statement that the epoxy compound (B2) has an alicyclic structure within its molecule means that it includes an alicyclic structure in addition to the epoxy ring structure. However, the alicyclic structure in this embodiment includes a fused ring structure in which an epoxy ring and an aliphatic ring are fused, and a spiro-ring structure in which an epoxy ring and an aliphatic ring are bonded by a spiro-bonding atom. The number of members in the alicyclic structure is not particularly limited, but is preferably 4-membered to 10-membered rings, more preferably 4-membered to 8-membered rings, and even more preferably 5-membered or 6-membered rings. Furthermore, compounds having an alicyclic structure within the molecule are preferably compounds having two or more alicyclic structures within the molecule.

[0053] The epoxy compound (B2) may contain a polyfunctional epoxy compound or a monofunctional epoxy compound, but from the viewpoint of further improving the curing speed of the resin composition and further improving the crosslinking density of the cured product made from the resin composition, it preferably contains a polyfunctional epoxy compound. The polyfunctional epoxy compound preferably comprises at least one selected from the group consisting of difunctional epoxy compounds and trifunctional epoxy compounds, and more preferably comprises a difunctional epoxy compound.

[0054] The refractive index of the epoxy compound (B2) is preferably 1.45 or higher, more preferably 1.48 or higher, and even more preferably 1.50 or higher, from the viewpoint of further improving the optical propagation efficiency of the optical waveguide. The upper limit is not particularly limited, but may be, for example, 1.55 or lower, 1.54 or lower, or 1.53 or lower. Furthermore, the refractive index of the epoxy compound (B2) is preferably 1.45 or higher and 1.55 or lower, more preferably 1.48 or higher and 1.54 or lower, and even more preferably 1.50 or higher and 1.53 or lower, from the viewpoint of further improving the optical propagation efficiency of the optical waveguide. The refractive index of epoxy compound (B2) refers to the refractive index measured at 23°C and 589 nm using an Abbe refractometer.

[0055] The content of compound (B) having a cyclic ether structure in the resin composition of this embodiment is preferably 21 parts by mass or more and 100 parts by mass or less, more preferably 26 parts by mass or more and 70 parts by mass or less, even more preferably 30 parts by mass or more and 50 parts by mass or less, even more preferably 32 parts by mass or more and 45 parts by mass or less, and even more preferably 34 parts by mass or more and 40 parts by mass or less, when the content of resin (A) having a norbornene skeleton in the resin composition is 100 parts by mass.

[0056] The content of the oxetane compound (B1) in the resin composition of this embodiment is preferably 20 parts by mass or more and 50 parts by mass or less, more preferably 25 parts by mass or more and 40 parts by mass or less, and even more preferably 30 parts by mass or more and 35 parts by mass or less, when the content of the resin (A) having a norbornene skeleton in the resin composition is 100 parts by mass.

[0057] The content of the epoxy compound (B2) in the resin composition of this embodiment is preferably 1 to 10 parts by mass, more preferably 2 to 8 parts by mass, and even more preferably 3 to 6 parts by mass, when the content of the resin (A) having a norbornene skeleton in the resin composition is 100 parts by mass.

[0058] The compound (B) having a cyclic ether structure preferably includes an oxetane compound (B1) and an epoxy compound (B2). The mass ratio (B1 / B2) of the content of the oxetane compound (B1) in the resin composition to the content of the epoxy compound (B2) in the resin composition of this embodiment is preferably 3.0 to 20.0, more preferably 5.0 to 15.0, and even more preferably 7.0 to 10.0.

[0059] Compound (B) having a cyclic ether structure may be a compound having one cyclic ether structure, or it may contain two or more compounds having cyclic ether structures.

[0060] <Photosensitive agent (C)> The resin composition of this embodiment preferably further comprises a photosensitive agent (C). The photosensitive agent (C) is not particularly limited, as long as it is capable of generating active species in response to light to cure the photosensitive resin composition.

[0061] The photosensitive agent (C) comprises, for example, at least one selected from the group consisting of photocationic polymerization initiators and photoradical polymerization initiators, and preferably comprises a photocationic polymerization initiator.

[0062] The photocationic polymerization initiator comprises, for example, at least one selected from the group consisting of sulfonium salt type polymerization initiators and iodonium salt type polymerization initiators, preferably a sulfonium salt type polymerization initiator, more preferably a triarylsulfonium salt type polymerization initiator, and even more preferably a triphenylsulfonium salt type polymerization initiator.

[0063] The content of the photosensitive agent (C) in the resin composition of this embodiment is preferably 0.05 parts by mass or more and 3 parts by mass or less, more preferably 0.1 parts by mass or more and 2 parts by mass or less, and even more preferably 0.3 parts by mass or more and 1 part by mass or less, when the content of the resin (A) having a norbornene skeleton in the resin composition is 100 parts by mass.

[0064] The photosensitive agent (C) may be one type of photosensitive agent or may contain two or more types of photosensitive agents.

[0065] <Antioxidant (D)> The resin composition of this embodiment preferably further comprises an antioxidant (D). The antioxidant (D) is not particularly limited and includes, for example, at least one selected from the group consisting of phenol-type antioxidants, phosphorus-type antioxidants, amine-type antioxidants, and thioether-type antioxidants, and preferably at least one selected from the group consisting of phenol-type antioxidants and phosphorus-type antioxidants. The antioxidant (D) in this embodiment may be one type of antioxidant, or it may contain two or more types of antioxidants.

[0066] The content of the antioxidant (D) in the resin composition of this embodiment is preferably 0.05 parts by mass or more and 10 parts by mass or less, more preferably 0.1 parts by mass or more and 5 parts by mass or less, and even more preferably 0.5 parts by mass or more and 3 parts by mass or less, when the content of the resin (A) having a norbornene skeleton in the resin composition is 100 parts by mass.

[0067] <Organic solvent (E)> The resin composition of this embodiment may contain an organic solvent (E). When the resin composition of this embodiment contains an organic solvent (E), it can be made into a varnish-like resin composition.

[0068] The organic solvent (E) of this embodiment includes, for example, at least one selected from the group consisting of acetone, methyl ethyl ketone, methyl amyl ketone, toluene, propylene glycol monomethyl ether, propylene glycol methyl ethyl ether, propylene glycol dimethyl ether, propylene glycol 1-monomethyl ether 2-acetate, diethylene glycol ethyl methyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, benzyl alcohol, propylene carbonate, ethylene glycol diacetate, propylene glycol diacetate, propylene glycol monomethyl ether acetate, dipropylene glycol methyl-n-propyl ether, butyl acetate, γ-butyrolactone, methyl lactate, ethyl lactate, and butyl lactate. The organic solvent (E) in this embodiment may be one type of organic solvent, or it may contain two or more types of organic solvents.

[0069] When the resin composition of this embodiment contains an organic solvent (E), the concentration of total solids (non-volatile components) in the resin composition is preferably 10% by mass or more and 60% by mass or less, more preferably 20% by mass or more and 55% by mass or less, and even more preferably 25% by mass or more and 50% by mass or less, from the viewpoint of appropriately controlling the viscosity of the resin composition and sufficiently dissolving each component in the resin composition.

[0070] <Other ingredients> The resin composition of this embodiment may further contain, for example, surfactants, curing aids, leveling agents, colorants, preservatives, plasticizers, fillers, inorganic particles, degradation inhibitors, wettability improvers, antistatic agents, etc. The content of other components is appropriate.

[0071] The total content of the resin (A) having a norbornene skeleton and the compound (B) having a cyclic ether structure in the resin composition of this embodiment is preferably 50% by mass or more and less than 100% by mass, more preferably 70% by mass or more and less than 100% by mass, even more preferably 80% by mass or more and less than 100% by mass, even more preferably 90% by mass or more and less than 100% by mass, and even more preferably 95% by mass or more and less than 100% by mass, when the total amount of nonvolatile components in the resin composition is 100% by mass.

[0072] The total content of the resin (A) having a norbornene skeleton and the compound (B) having a cyclic ether structure in the resin composition of this embodiment is, from the viewpoint of adjusting the storage modulus E', refractive index, etc. of the cured product made from the resin composition to more appropriate values, preferably 20% by mass or more and less than 100% by mass, more preferably 25% by mass or more and less than 100% by mass, even more preferably 50% by mass or more and less than 100% by mass, even more preferably 70% by mass or more and less than 100% by mass, even more preferably 80% by mass or more and less than 100% by mass, even more preferably 90% by mass or more and less than 100% by mass, and even more preferably 95% by mass or more and less than 100% by mass, when the total content of all components in the resin composition is taken as 100% by mass.

[0073] [Method for producing resin composition] The resin composition of this embodiment can be obtained, for example, by mixing each component. A film-like resin composition can be obtained, for example, by applying a varnish-like resin composition onto a base film and drying it.

[0074] [Dry film] The dry film of this embodiment comprises a resin layer made of the resin composition of this embodiment.

[0075] The resin composition forming the resin layer in this embodiment may be an uncured product, a semi-cured product, or a cured product, but it is preferably a semi-cured product.

[0076] The thickness of the resin layer in this embodiment is preferably 1 μm to 100 μm, more preferably 5 μm to 80 μm, even more preferably 10 μm to 60 μm, and even more preferably 30 μm to 50 μm.

[0077] The light transmittance of the resin layer in this embodiment for a wavelength of 850 nm is preferably 85% to 100%, more preferably 90% to 100%, more preferably 95% to 100%, more preferably 97% to 100%, and more preferably 98% to 100%, from the viewpoint of further improving the light propagation efficiency of the optical waveguide. The light transmittance of the resin layer at a wavelength of 850 nm refers to the light transmittance value measured by an ultraviolet-visible spectrophotometer.

[0078] The dry film of this embodiment preferably further comprises a base film and has a resin layer on the base film. For example, a resin film can be used as the base film. The resin constituting the base film is not particularly limited and includes, for example, at least one selected from the group consisting of polyethylene terephthalate and polyimide, and preferably includes polyethylene terephthalate.

[0079] From the viewpoint of further improving the handling of the dry film, the thickness of the base film in this embodiment is preferably 10 μm to 100 μm, more preferably 15 μm to 80 μm, even more preferably 20 μm to 60 μm, and even more preferably 25 μm to 40 μm.

[0080] The base film of this embodiment may be subjected to surface treatments such as antistatic treatment and mold release treatment.

[0081] The dry film of this embodiment may further include a cover film. Preferably, the cover film is provided in direct contact with the resin layer. When the dry film of this embodiment includes a base film, the cover film is preferably provided on the side of the resin layer opposite to the base film. The cover film is not particularly limited, but for example, an OPP cover film can be used.

[0082] The dry film of this embodiment can be obtained, for example, by applying the varnish-like resin composition of this embodiment onto a base film and drying it. Methods of application include, for example, direct application using various coating devices such as pin coaters, die coaters, comma coaters, and curtain coaters, as well as printing methods such as screen printing.

[0083] [Optical waveguide] The optical waveguide of this embodiment comprises a core layer and a cladding layer, wherein the core layer is a layer containing the resin composition of this embodiment.

[0084] Figure 1 is a schematic cross-sectional view showing an example of the structure of the optoelectronic composite substrate of this embodiment. The optical waveguide of this embodiment will be explained using Figure 1. In Figure 1, the optical waveguide 100 comprises a first cladding layer 20, a core layer 30, and a second cladding layer 40 in this order. In this specification, when the optical waveguide 100 is provided on a substrate 110, the cladding layer located on the substrate 110 side is referred to as the first cladding layer 20. Furthermore, hereafter, when simply referred to as "cladding layer," the concept includes both the first cladding layer 20 and the second cladding layer 40.

[0085] The core layer 30 is a layer containing the resin composition of this embodiment. The resin composition contained in the core layer 30 may be uncured, semi-cured, or cured, but is preferably cured.

[0086] The preferred numerical range for the thickness of the core layer 30 is the same as the preferred numerical range for the thickness of the resin layer of the dry film in this embodiment.

[0087] The core layer 30 may have a waveguide pattern formed on it. Examples of methods for forming the waveguide pattern include exposure, etching, and replication.

[0088] The cladding layer of this embodiment is preferably a layer containing a resin composition that can be used as a cladding layer. The resin composition contained in the cladding layer of this embodiment may be uncured, semi-cured, or cured, but is preferably cured.

[0089] The thickness of the first cladding layer 20 is preferably 1 μm to 150 μm, more preferably 5 μm to 100 μm, even more preferably 10 μm to 50 μm, and even more preferably 15 μm to 35 μm, from the viewpoint of further improving the optical propagation efficiency of the optical waveguide. The thickness of the second cladding layer 40 is preferably 1 μm to 150 μm, more preferably 3 μm to 100 μm, even more preferably 5 μm to 70 μm, even more preferably 8 μm to 50 μm, and even more preferably 8 μm to 20 μm, from the viewpoint of further suppressing thermal deformation of the optical waveguide.

[0090] The optical waveguide 100 may have mirrors formed on it. One method for forming the mirrors is to create an inclined surface by laser processing or the like.

[0091] In addition to the first cladding layer 20, the core layer 30, and the second cladding layer 40, the optical waveguide 100 may also include other layers, provided that they do not affect the good performance of the optical waveguide 100.

[0092] [Optoelectric composite substrate] The optoelectronic composite substrate of this embodiment will be described with reference to Figure 1. The optoelectronic composite substrate 200 comprises a substrate 110 and an optical waveguide 100 provided on the substrate 110.

[0093] The substrate 110 can be, for example, a printed circuit board or a flexible circuit board, and is preferably a flexible circuit board. The substrate 110 may have vias formed on it.

[0094] The optoelectronic composite substrate 200 may further include a polyimide substrate on the side of the second cladding layer 40 opposite to the core layer 30.

[0095] The photoelectric composite substrate 200 may include light-emitting elements, light-receiving elements, and the like.

[0096] The optoelectronic composite substrate 200 can be obtained, for example, by (i) forming a first cladding layer 20 on a substrate 110, (ii) forming a core layer 30 on the first cladding layer 20, and (iii) forming a second cladding layer 40 on the core layer 30. Methods for forming each layer include, for example, laminating each layer sequentially by rolling a dry film to form each layer using methods such as roll lamination, vacuum roll lamination, flat lamination, vacuum flat lamination, atmospheric pressure pressing, and vacuum pressing.

[0097] [Electronic components] The electronic component of this embodiment includes the photoelectric composite substrate of this embodiment. Examples of electronic components in this embodiment include those found in electronic devices such as mobile phones, game consoles, routers, WDM devices, personal computers, televisions, and home servers.

[0098] The embodiments of the present invention have been described above, but these are merely examples, and various other configurations can also be adopted. Furthermore, the present invention is not limited to the embodiments described above, and any modifications, improvements, etc., that can achieve the objectives of the present invention are included in the present invention. [Examples]

[0099] The embodiment will be described in detail below based on examples and comparative examples. However, this embodiment is not limited in any way to the descriptions of these examples.

[0100] [Raw materials] First, let me explain the raw materials.

[0101] <Synthesis of resins> (Synthesis of resin (A-1)) In a glove box filled with dry nitrogen, where both moisture and oxygen concentrations were controlled to 1 ppm or less, 7.1 g (40.0 mmol) of n-hexylnorbornene and 12.8 g (40.0 mmol) of diphenylmethylnorbornenemethoxysilane were weighed into a 500 mL vial. 60 g of dehydrated toluene and 11 g of ethyl acetate were added, and the vial was sealed tightly with a silicone sealer. Next, 1.56 g (3.2 mmol) of Ni catalyst and 10 mL of anhydrous toluene were weighed into a 100 mL vial, a stirrer tip was added, and the vial was sealed tightly. The Ni catalyst was thoroughly stirred to completely dissolve it, obtaining the Ni catalyst solution. 1 mL of the Ni catalyst solution was accurately weighed using a syringe and quantitatively injected into the vial containing the two types of norbornene dissolved above. The vial was stirred at room temperature for 1 hour, and a significant increase in viscosity was observed. At this point, the stopper was removed, 60 g of tetrahydrofuran (THF) was added, and the mixture was stirred to obtain the reaction solution. A peracetic acid aqueous solution was prepared by adding 9.5 g of acetic anhydride, 18 g of hydrogen peroxide solution (30% concentration), and 30 g of deionized water to a 100 mL beaker and stirring. Next, the entire peracetic acid aqueous solution was added to the above reaction solution and stirred for 12 hours to perform the reduction treatment of Ni. Next, the completed reaction solution was transferred to a separatory funnel, the aqueous layer at the bottom was removed, and then 100 mL of a 30% aqueous solution of isopropyl alcohol was added and the mixture was vigorously stirred. After standing, complete two-layer separation occurred, and the aqueous layer was removed. This washing process was repeated a total of three times. Then, the oil layer was dropped into a large excess of acetone to reprecipitate the resulting polymer, which was separated from the filtrate by filtration. Finally, the polymer was heated and dried in a vacuum dryer set to 60°C for 12 hours to obtain a resin (A-1) having a norbornene skeleton. The weight-average molecular weight (Mw) of resin (A-1) having a norbornene skeleton was 150,000, as measured by GPC, and the refractive index of resin (A-1) having a norbornene skeleton at 23°C and 589 nm, as measured by Abbe refractometer, was 1.558. A high-speed GPC instrument (Tosoh Corporation, product name: HLC-8420GPC) was used for the GPC measurements. Furthermore, identification by NMR revealed that the molar ratio of each structural unit in the resin (A-1) having a norbornene skeleton was 60 mol% for structural units derived from n-hexylnorbornene and 40 mol% for structural units derived from diphenylmethylnorbornenemethoxysilane.

[0102] The details of the raw materials for each component in Table 1 are as follows:

[0103] <Resin having a norbornene skeleton (A)> (A-1) The resin synthesized above

[0104] [ka]

[0105] <Compound having a cyclic ether structure (B)> (B-1) OXT-213 (manufactured by Toagosei Co., Ltd., CHOX, monofunctional oxetane compound, refractive index 1.46, liquid at 23°C) (B-2) OXT-212 (manufactured by Toagosei Co., Ltd., EHOX, monofunctional oxetane compound, refractive index 1.44, liquid at 23°C) (B-3) Celoxide 2021P (manufactured by Daicel Corporation, bifunctional epoxy compound, refractive index 1.51, liquid at 23°C) (B-4) Celoxide 8010 (manufactured by Daicel Corporation, bifunctional epoxy compound, refractive index 1.51, liquid at 23°C) (B-5) VNBB-NB (manufactured by ENEOS Corporation, monofunctional epoxy compound, refractive index 1.52, liquid at 23°C) (B-6) DE-102 (manufactured by ENEOS Corporation, a bifunctional epoxy compound, solid at 23°C)

[0106] [ka]

[0107] <Photosensitive agent (C)> (C-1) CPI-310B (manufactured by Sunapro Co., Ltd., photocationic polymerization initiator)

[0108] <Antioxidant (D)> (D-1) Irganox 1076 (BASF, hindered phenol type antioxidant) (D-2) Irgafos168 (BASF, phosphorus-type antioxidant)

[0109] <Organic solvent (E)> (E-1) Toluene

[0110] [Examples 1-7 and Comparative Examples 1-2] <Preparation of resin composition> Each raw material, formulated according to Table 1, was stirred at room temperature until the raw materials were completely dissolved to obtain a solution. The solution was then filtered through a PTFE filter with a pore size of 0.2 μm to obtain the resin compositions of Examples 1-7 and Comparative Examples 1-2, respectively.

[0111] <Preparation of dry film> The resin compositions of Examples 1-7 and Comparative Examples 1-2 were coated onto a release-treated PET film using an applicator to achieve a dry film thickness of 40 μm. After coating, the films were placed in a 45°C dryer for 5 minutes to completely remove the solvent and form a coating. Finally, a PET cover film was attached to the surface of the resin layer formed by the resin composition to obtain the dry films of Examples 1-7 and Comparative Examples 1-2, respectively. In the preparation of evaluation samples described later, the dry film for the core layer refers to the dry films of Examples 1-7 and Comparative Examples 1-2, respectively.

[0112] [evaluation] The evaluations for Examples 1-7 and Comparative Examples 1-2 are described below. The evaluation results are shown in Table 1. In Table 1, "-" indicates that measurement was not performed.

[0113] <Storage modulus E' and loss modulus E'' of the cured material at 30°C> The resin layers formed from the resin compositions of the dry films of Examples 1-7 and Comparative Examples 1-2 were subjected to an integrated light intensity of 120 mJ / cm² in an atmospheric environment. 2 After irradiation with light under the specified conditions, a cured product consisting of a resin composition with a thickness of 40 μm was obtained by curing by heating in an atmospheric environment at 60°C for 4 hours. The obtained cured product was heated from 30°C to 300°C using a dynamic viscoelasticity analyzer (T.A. Instrument Japan Co., Ltd., product name: DMA Q-800) in an atmospheric environment at a frequency of 1 Hz, in tensile mode, with a sample distance of 2 cm, a sample width of 1 cm, and a heating rate of 5°C / min. The storage modulus E' and loss modulus E'' of the cured product were measured with respect to temperature, and the storage modulus E' [MPa] at 30°C and the loss modulus E'' [MPa] at 30°C were calculated.

[0114] <Evaluation of coating properties> In the preparation of the dry films for Examples 1-7 and Comparative Examples 1-2, the coating properties were evaluated based on the following criteria. A: When the resin composition was coated onto the PET film substrate, no repellency between the PET film substrate and the resin composition was observed. B: When the resin composition was coated onto the PET film substrate, 1-2 point repellencies occurred at the edges of the PET film substrate and the resin composition.

[0115] <Refractive index of dry film> For the dry films of Examples 1-7 and Comparative Examples 1-2, the PET cover film was peeled off, and the refractive index was measured at 23°C and 589 nm using an Abbe refractometer (manufactured by Atago Co., Ltd., product name: NAR-1T SOLID).

[0116] <Light transmittance of dry film at a wavelength of 850 nm> For the dry films of Examples 1-7 and Comparative Examples 1-2, the PET cover film was peeled off, and the films were laminated onto a slide glass with the resin layer formed by the resin composition facing the slide glass side under the conditions of temperature: 100°C, pressure: 0.5 MPa, and time: 2 minutes. After that, the base film was peeled off to obtain a sample for transmittance measurement (slide glass with resin composition). Subsequently, a 100% correction was performed using a UV-Vis spectrophotometer (JASCO Corporation, product name: V-670) with slide glass placed in both the background slot and the sample slot. The slide glass on the measurement slot side was then replaced with the transmittance measurement sample, and the light transmittance [%] at a wavelength of 850 nm was measured in transmittance measurement mode.

[0117] <Evaluation of the amount of curvature> First, we will explain the method for preparing samples for evaluating warpage.

[0118] (Preparation of the dry film for the first cladding layer) (Synthesis of polyimide resin) 67.3 g (0.210 mol) of 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 97.7 g (0.220 mol) of 4,4'-(hexafluoroisopropylidene)diphthalic acid dianhydride, and 495 g of dimethylacetamide were charged into a 3 L separable glass flask equipped with a stirrer and stirring blades, and stirred until dissolved. Further stirring was carried out at room temperature under a nitrogen stream for 12 hours to carry out the polymerization reaction and obtain a polyamic acid solution. After adding 16 g of pyridine to the obtained polyamic acid solution, 82 g of acetic anhydride was added dropwise at room temperature. Subsequently, the mixture was stirred for 24 hours while maintaining the liquid temperature at 20-100°C to carry out the imidation reaction and obtain a polyimide solution. The obtained polyimide solution was added to 1,000 g of methanol in a 5 L container while stirring to precipitate the polyimide resin. The solid polyimide resin was then filtered off using a suction filtration device, and the mixture was further washed with 1,000 g of methanol. Finally, the mixture was dried in a vacuum dryer at 100°C for 24 hours, and then at 200°C for 3 hours to obtain powdered polyimide resin. The weight-average molecular weight (Mw) of the polyimide resin, as determined by GPC measurement, was 51,000. 1 ¹H-NMR measurements were performed, and the imidation rate was calculated from the quantitative values ​​of the amide peak relative to the aromatic ring peak of the polyimide. The result showed that the imidation rate was over 99%. Furthermore, polyimide resin was dissolved in propylene glycol monomethyl ether acetate to a solid content concentration of 25%, then coated using an applicator to a film thickness of 30 μm, and finally dried in an oven at 100°C for 10 minutes to obtain a polyimide coating. The refractive index of the obtained coating was measured using an Abbe refractometer (manufactured by Atago Co., Ltd., product name: NAR-1T SOLID) under conditions of 23°C and 589 nm, and the refractive index of the polyimide was found to be 1.54.

[0119] (Preparation of the resin composition for the first cladding layer) To 187 parts by mass of propylene glycol monomethyl ether acetate and 47 parts by mass of propylene glycol monomethyl ether, 50 parts by mass of the polyimide resin synthesized above, 50 parts by mass of OXT-221 (manufactured by Toagosei Co., Ltd., DOX, a polyfunctional oxetane compound), 0.15 parts by mass of CPI-310B (manufactured by Sunapro Co., Ltd., a photocationic polymerization initiator), and 0.1 parts by mass of BYK-333 (manufactured by Bic Chemie Japan Co., Ltd., a silicone-based surfactant) were stirred at room temperature until completely dissolved to obtain a solution. Subsequently, the solution was filtered through a PTFE filter with a pore size of 0.2 μm to obtain a varnish-like resin composition for the first cladding layer.

[0120] (Preparation of the dry film for the first cladding layer) The first cladding layer resin composition obtained above was applied to a polyethylene terephthalate substrate with a release treatment and a thickness of 38 μm using an applicator, with varnish applied so that the thickness after drying was 25 μm. After drying at 100°C for 10 minutes, an OPP cover film was attached to the surface of the resin layer formed by the resin composition to obtain the first cladding layer dry film.

[0121] (Preparation of samples for evaluating warpage) An LCP substrate measuring 9 cm in width, 13 cm in length, and 50 μm in thickness was placed on a stainless steel plate. After peeling off the OPP cover film of the first cladding layer dry film, the LCP substrate was laminated using a vacuum laminator (manufactured by Nikko Materials Co., Ltd., model name: CVP-300) under the conditions of temperature: 140°C, pressure: 0.5 MPa, and time: 120 seconds, so that the first cladding resin layer in the first cladding layer dry film and the LCP substrate were in contact. A laminate A was obtained with the layer configuration of "LCP substrate / first cladding resin layer / PET substrate". Here, the PET substrate is derived from the first cladding layer dry film. Next, using a high-pressure mercury lamp, an integrated light intensity of 1000 mJ / cm² was applied to the entire dry film for the first cladding layer in laminate A. 2 The exposure was performed under the following conditions.

[0122] After peeling off the PET substrate from laminate A and the PET cover film from the dry film for the core layer, the laminates were laminated using a vacuum laminator (manufactured by Nikko Materials Co., Ltd., model name: CVP-300) under the conditions of temperature: 60°C, pressure: 0.5 MPa, and time: 30 seconds, so that the first cladding resin layer in laminate A and the core forming resin layer in the dry film for the core layer were in contact. Laminate B was obtained with the layer configuration of "LCP substrate / first cladding resin layer / core forming resin layer / PET substrate". Here, the PET substrate is derived from the dry film for the core layer. Next, the resin layer for core formation was exposed using a direct-writing exposure machine (SCREEN Corporation, product name: LI-9000) with an integrated light intensity of 80 mJ / cm². 2 Under these conditions, 20 line-and-space lines were created, each 9 cm long with an exposed area of ​​10 μm and an unexposed area of ​​50 μm. Subsequently, the PET substrate derived from the dry film for the core layer was peeled off, and the laminate B was heat-treated by heating it in an atmospheric oven at 60°C for 4 hours. Laminate B, after heat treatment, was used as a sample for evaluating the amount of warpage.

[0123] The PET substrate side of the warpage evaluation sample was placed facing upwards on a flat surface and left to stand for 10 minutes. The vertical distance between the vertices of the warpage evaluation sample and the surface was then measured. The vertical distance from the surface was measured at each of the four vertices of the warpage evaluation sample, and the average value was evaluated as the warpage. Here, since the warpage evaluation sample is rectangular, the four vertices of the warpage evaluation sample refer to the four corners of the rectangle. Samples with a curvature of 15 mm or less were evaluated as A, and samples with a curvature greater than 15 mm were evaluated as B.

[0124] <Optical properties> First, the method for preparing the samples for optical property evaluation will be explained. Here, the dry film for the first cladding layer used in the preparation of the optical property evaluation samples was the same as the dry film for the first cladding layer used in the samples for warpage evaluation.

[0125] (Preparation of the dry film for the second cladding layer) (Preparation of the resin composition for the second cladding layer) To 187 parts by mass of propylene glycol monomethyl ether acetate and 47 parts by mass of propylene glycol monomethyl ether, 50 parts by mass of polyimide resin, 50 parts by mass of OXT-221 (manufactured by Toagosei Co., Ltd., DOX, a polyfunctional oxetane compound), 3 parts by mass of Cureazole C11z (manufactured by Shikoku Chemicals Co., Ltd., an imidazole compound), and 0.1 parts by mass of BYK-333 (manufactured by Bic Chemie Japan Co., Ltd., a silicone-based surfactant) were stirred at room temperature until completely dissolved to obtain a solution. Subsequently, the solution was filtered through a PTFE filter with a pore size of 0.2 μm to obtain a varnish-like resin composition for the second cladding layer. Here, the polyimide resin used was the same resin synthesized in the first cladding layer resin composition.

[0126] (Preparation of the dry film for the second cladding layer) The second cladding layer resin composition obtained above was applied to a 25 μm thick polyimide substrate using an applicator, with varnish applied to achieve a dry thickness of 12 μm. After drying at 100°C for 10 minutes, an OPP cover film was attached to the surface of the resin layer formed by the resin composition to obtain a second cladding layer dry film.

[0127] (Preparation of samples for optical property evaluation) A 25 μm thick polyimide substrate was bonded to a 188 μm thick carrier film (manufactured by Nippa Co., Ltd., product name: MP188) using a bonding device. A laminate a was obtained in which the layer structure was "carrier film / polyimide substrate". Here, laminate a is a laminate with a width of 9 cm and a length of 13 cm.

[0128] Laminate a was placed on a stainless steel plate. After peeling off the OPP cover film of the first cladding dry film, the laminate a was laminated using a vacuum laminator (manufactured by Nikko Materials Co., Ltd., model name: CVP-300) at a temperature of 140°C, a pressure of 0.5 MPa, and a time of 120 seconds, so that the first cladding resin layer in the first cladding dry film and the polyimide substrate in laminate a were in contact. Laminate b was obtained with a layer structure of "carrier film / polyimide substrate / first cladding resin layer / PET substrate". Here, the PET substrate is derived from the first cladding dry film. Next, using a high-pressure mercury lamp, an integrated light intensity of 1000 mJ / cm² was applied to the entire dry film for the first cladding layer in laminate b. 2 The exposure was performed under the following conditions.

[0129] After peeling off the PET substrate from laminate b and the PET cover film from the dry film for the core layer, the laminate was laminated using a vacuum laminator (manufactured by Nikko Materials Co., Ltd., model name: CVP-300) under the conditions of temperature: 60°C, pressure: 0.5 MPa, and time: 30 seconds, so that the first cladding resin layer in laminate b and the core forming resin layer in the film for forming the core layer were in contact. A laminate c was obtained with the layer structure of "carrier film / polyimide substrate / first cladding resin layer / core forming resin layer / PET substrate". Here, the PET substrate is a PET substrate derived from the dry film for the core layer. Next, the resin layer for core formation was exposed using a direct-writing exposure machine (SCREEN Corporation, product name: LI-9000) with an integrated light intensity of 80 mJ / cm². 2 Under these conditions, 20 line-and-space lines were created, each 9 cm long with an exposed area of ​​10 μm and an unexposed area of ​​50 μm. Subsequently, the PET substrate derived from the dry film for the core layer was peeled off, and the laminate c was heat-treated by heating it in an atmospheric oven at 60°C for 4 hours.

[0130] Next, after peeling off the OPP cover film from the dry film for the second cladding layer, the core-forming resin layer in the laminate c and the second cladding resin layer in the dry film for the second cladding layer were laminated using a vacuum laminator (manufactured by Nikko Materials Co., Ltd., machine name: CVP-300) under the conditions of temperature: 140°C, pressure: 0.5 MPa, and time: 120 seconds, so that they were in contact. A laminate d was obtained with the layer configuration of "carrier film / polyimide substrate / first cladding resin layer / core-forming resin layer / second cladding resin layer / polyimide substrate". Here, the polyimide substrate located in the outermost layer is a polyimide substrate derived from the film for forming the second cladding layer. The laminate d was heat-treated in an atmospheric oven at 125°C for 1 hour, and then at 180°C for 30 minutes to cure the first cladding resin layer, the core forming resin layer, and the second cladding resin layer, respectively. The laminated material d after heat treatment was used as a sample for optical property evaluation.

[0131] (Insertion loss) Light emitted from an 850 nm VCSEL (surface-emitting laser) was introduced into an optical waveguide in a sample for optical property evaluation via a 50 μm diameter optical fiber. The emitted light was received by a 50 μm diameter optical fiber, and the light intensity was measured. Specifically, for the optical waveguides obtained in each example and comparative example, measurements were taken with a sample size of 7 cm in accordance with section 4.6.1, "Measurement method for insertion loss," of the "Test method for polymer optical waveguides (JPCA-PE02-05-01S-2008)" specified by the Japan Electronic Circuits Manufacturers Association. For the evaluation of insertion loss, samples with an insertion loss of 2.0 dB or less were evaluated as A, samples with an insertion loss of 2.1 dB or more and 3.0 dB or less as B, and samples with an insertion loss of 3.1 dB or more as C.

[0132] (Refractive index of the sample for optical property evaluation) The refractive index was measured in the exposed and unexposed areas of the core layer of a sample used for optical property evaluation, using a prism coupler (Metricon, USA, part number: Model 2010). The measurement conditions were as follows: Measurement temperature: 25℃ (indoor temperature) Measurement wavelength: 633nm

[0133] (Light transmittance of samples used for optical property evaluation) For the exposed and unexposed areas of the core layer in the sample used for optical property evaluation, the light transmittance [%] at a wavelength of 850 nm was measured using a spectrophotometer (JASCO Corporation, product name: V-670 EX) with an integrating sphere.

[0134] [Table 1]

[0135] Table 1 shows that the evaluation results for the amount of warpage were all good in the examples. In other words, the resin composition of this embodiment can suppress the warpage of the laminate, which is an intermediate in the optical waveguide manufacturing process. [Explanation of Symbols]

[0136] 20. First cladding layer 30 core layers 40. Second cladding layer 100 optical waveguide 110 circuit boards 200 Optoelectronic composite substrate

Claims

1. A resin composition that can be used in the core layer of an optical waveguide, A resin composition having a storage modulus E' at 30°C of a cured product made from the resin composition calculated by the method described below, which is 100 MPa or more and 1000 MPa or less. [method] Integrated light intensity of 120 mJ / cm² under atmospheric conditions ２ After irradiating with light under the specified conditions, a cured product made of the resin composition with a thickness of 40 μm is heated in an atmospheric environment at 60°C for 4 hours. Using a dynamic viscoelasticity measuring device, the product is heated from 30°C to 300°C in an atmospheric environment at a frequency of 1 Hz, in tensile mode, with a sample distance of 2 cm, a sample width of 1 cm, and a heating rate of 5°C / min. The storage modulus E' and loss modulus E'' with respect to temperature are measured, and the storage modulus E' at 30°C and loss modulus E'' at 30°C of the cured product made of the resin composition are calculated.

2. The resin composition according to claim 1, wherein the loss modulus E'' of the cured product made from the resin composition calculated by the above method is 10 MPa or more and 200 MPa or less at 30°C.

3. A resin composition according to claim 1 or 2, comprising a resin (A) having a norbornene skeleton and a compound (B) having a cyclic ether structure.

4. The resin composition according to claim 3, wherein the content of the compound (B) having the cyclic ether structure in the resin composition is 21 parts by mass or more and 100 parts by mass or less, when the content of the resin (A) having the norbornene skeleton in the resin composition is 100 parts by mass.

5. The resin composition according to claim 3, wherein the compound (B) having the cyclic ether structure comprises at least one selected from the group consisting of oxetane compounds (B1) and epoxy compounds (B2).

6. The compound (B) having the cyclic ether structure includes an oxetane compound (B1), The resin composition according to claim 3, wherein the oxetane compound (B1) comprises a monofunctional oxetane compound.

7. The resin composition according to claim 3, wherein the resin (A) having a norbornene skeleton includes a resin having an aromatic ring.

8. The resin composition according to claim 3, further comprising a photosensitive agent (C).

9. The resin composition according to claim 1 or 2, wherein the refractive index is 1.51 or more and 1.60 or less.

10. A dry film comprising a resin layer made of the resin composition according to claim 1 or 2.

11. The dry film according to claim 10, wherein the light transmittance of the resin layer at a wavelength of 850 nm is 85% or more.

12. An optical waveguide comprising a core layer and a cladding layer, An optical waveguide in which the core layer is a layer containing the resin composition described in claim 1 or 2.

13. circuit board and An optoelectronic composite substrate comprising an optical waveguide according to claim 12 provided on the substrate.

14. An electronic component comprising the optoelectronic composite substrate described in claim 13.

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