Resin composition

Abstract

The present invention provides: a resin composition from which it is possible to stably obtain an optical waveguide having a small optical transmission loss; a resin sheet containing the resin composition; a resin composition set containing the resin composition; an optical waveguide including a cured product of the resin composition; and an opto-electrical hybrid substrate provided with the optical waveguide. This resin composition contains (A) an epoxy resin, (B) a photo curable resin, (C) a resin having a carboxyl group and an ethylenically unsaturated bond, and (D) a photoinitiator. In a cured object of (A) component, (B) component, and (C) component, the contained amounts of the respective components resulting in a refractive index difference of not less than 0.07 at a wavelength of 1310 nm is less than 10 mass% when the total of (A) component, (B) component, and (C) component is defined as 100 mass%.

Description

resin composition

[0001] The present invention relates to a resin composition, and further to a resin sheet, a resin composition set, an optical waveguide, a method for manufacturing an optical waveguide, and an optical-electrical hybrid board.

[0002] Technological advances such as 5G communications, autonomous driving, IoT, artificial intelligence, and big data are driving demands for ultra-high-speed and high-capacity communications. Semiconductor packages, which underpin these advances, have traditionally supported high-speed communications by passing high-frequency currents through them. However, in recent years, issues such as noise generation, communication loss, and heat generation due to high-speed communications have become apparent. To address these issues, active efforts have been made in recent years to implement optical circuits on electrical wiring boards to achieve energy-saving, low-latency, and high-speed communications (Patent Documents 1 and 2).

[0003] JP 2013-119605 A JP 2023-160657 A

[0004] Research into the introduction of silicon photonics is being actively conducted, particularly in data centers where high-speed transmission is required. Silicon photonics is highly compatible with conventional LSI manufacturing processes. Therefore, it is expected that the use of silicon photonics will enable the formation of nanometer-sized thin-wire waveguides at low cost, based on the technology cultivated in electronic circuit integration technology.

[0005] For example, silicon photonics is expected to enable the formation of optical integrated circuits on chips using thin-wire waveguides. When manufacturing an optoelectronic hybrid substrate equipped with such a chip, an optical waveguide is required on the optoelectronic hybrid substrate in order to extract signal light from the thin-wire waveguide within the chip to the outside of the chip and connect it to the wiring between chips. From the viewpoint of efficiently forming a fine optical waveguide, it is desirable to form the optical waveguide from a cured product of a resin composition. In this regard, the cured product of a resin composition may have a non-uniform refractive index compared to a cured product of a single resin, which increases the optical transmission loss of the optical waveguide and makes it difficult to consistently obtain an optical waveguide with low optical transmission loss. In particular, resin compositions subjected to an alkali development process (e.g., resin compositions containing a thermosetting resin and a resin having a carboxyl group) have significant non-uniformity in the refractive index of the cured product, making it particularly difficult to consistently obtain an optical waveguide with low optical transmission loss.

[0006] The present invention has been made in view of the above, and aims to provide a resin composition that can stably obtain an optical waveguide with low optical transmission loss; a resin sheet containing the resin composition; a resin composition set containing the resin composition; an optical waveguide that includes a cured product of the resin composition; a method for manufacturing the optical waveguide; and an optical-electrical hybrid board that includes the optical waveguide.

[0007] The present inventors have conducted extensive research to solve the above-mentioned problems. As a result, the present inventors have found that the above-mentioned problems can be solved by using a resin composition comprising (A) an epoxy resin, (B) a photocurable resin, (C) a resin having a carboxyl group and an ethylenically unsaturated bond, and (D) a photopolymerization initiator, wherein the content of components that result in a refractive index difference of 0.07 or more at a wavelength of 1310 nm in a cured product of each of the components (A), (B), and (C) is less than 10% by mass, where the total of the components (A), (B), and (C) is taken as 100% by mass, and thus the present invention has been completed. That is, the present invention includes the following.

[0008] <1> A resin composition comprising (A) an epoxy resin, (B) a photocurable resin, (C) a resin having a carboxyl group and an ethylenically unsaturated bond, and (D) a photopolymerization initiator, wherein, in a cured product of each of the components (A), (B), and (C), the content of components that result in a refractive index difference at a wavelength of 1,310 nm of 0.07 or more is less than 10% by mass when the total of the components (A), (B), and (C) is taken as 100% by mass. <2> The resin composition is such that, in the refractive index of a cured product of each of the components (A), (B), and (C) contained in the resin composition, the maximum refractive index is n ｍａｘ The minimum value of the refractive index is n ｍｉｎ When 0≦n ｍａｘ -n ｍｉｎ<0.07>. <3> The resin composition according to <1> or <2>, wherein the component (A) contains an epoxy resin having an alicyclic skeleton. <4> The resin composition according to any one of <1> to <3>, wherein the component (D) contains a photoradical generator. <5> The resin composition according to any one of <1> to <4>, further containing (E) a thermal curing accelerator. <6> A resin sheet comprising a support and a resin composition layer formed on the support, wherein the resin composition layer contains the resin composition according to any one of <1> to <5>. <7> A resin composition set comprising a core resin composition and a clad resin composition, wherein the core resin composition and the clad resin composition each contain the resin composition according to any one of <1> to <5>. <8> The resin composition set according to claim 7, which is a resin composition set for producing an optical waveguide capable of transmitting light having a wavelength of 1300 nm to 1320 nm. <9> An optical waveguide comprising a core layer and a clad layer, wherein the core layer and the clad layer each comprise a cured product of the resin composition according to any one of <1> to <5>. <10> The optical waveguide according to <9>, which is capable of transmitting light having a wavelength of 1300 nm to 1320 nm. <11> An optical-electrical hybrid board comprising the optical waveguide according to <9> or <10>. <12> A method for producing an optical waveguide, comprising the steps of: forming a first resin composition layer containing a cladding resin composition; curing the first resin composition layer; forming a second resin composition layer containing a core resin composition on the first resin composition layer; subjecting the second resin composition layer to an exposure treatment; subjecting the second resin composition layer to a development treatment; curing the second resin composition layer; forming a third resin composition layer containing a cladding resin composition on the second resin composition layer; and curing the third resin composition layer, in this order;

[0009] According to the present invention, it is possible to provide a resin composition that can stably produce an optical waveguide with low optical transmission loss; a resin sheet containing the resin composition; a resin composition set that contains the resin composition; an optical waveguide that contains a cured product of the resin composition; and an optical-electrical hybrid board that includes the optical waveguide.

[0010] FIG. 1 is a perspective view schematically illustrating an optical waveguide according to one embodiment of the present invention. FIG. 2 is a schematic cross-sectional view illustrating step (1) of a method for manufacturing an optical waveguide according to one embodiment of the present invention. FIG. 3 is a schematic cross-sectional view illustrating step (2) of a method for manufacturing an optical waveguide according to one embodiment of the present invention. FIG. 4 is a schematic cross-sectional view illustrating step (3) of a method for manufacturing an optical waveguide according to one embodiment of the present invention. FIG. 5 is a schematic cross-sectional view illustrating step (4) of a method for manufacturing an optical waveguide according to one embodiment of the present invention. FIG. 6 is a schematic cross-sectional view illustrating step (5) of a method for manufacturing an optical waveguide according to one embodiment of the present invention. FIG. 7 is a schematic cross-sectional view illustrating step (6) of a method for manufacturing an optical waveguide according to one embodiment of the present invention. FIG. 8 is a schematic cross-sectional view illustrating step (7) of a method for manufacturing an optical waveguide according to one embodiment of the present invention. FIG. 9 is a schematic cross-sectional view illustrating step (8) of a method for manufacturing an optical waveguide according to one embodiment of the present invention. FIG. 10 is a schematic cross-sectional view illustrating step (9) of a method for manufacturing an optical waveguide according to one embodiment of the present invention.

[0011] The present invention will be described in detail below with reference to embodiments and examples. However, the present invention is not limited to the following embodiments and examples, and can be implemented with any modifications within the scope of the claims of the present invention and their equivalents.

[0012] [Explanation of Terms] In this specification, the term "(meth)acryloyl group" includes an acryloyl group, a methacryloyl group, and a combination thereof. The term "(meth)acrylate compound" refers to a compound having a (meth)acryloyl group, and includes an acrylate compound, a methacrylate compound, and a combination thereof. However, (meth)acrylate compounds do not include (meth)acrylic acid. The term "(meth)acrylic acid" includes acrylic acid, methacrylic acid, and a combination thereof.

[0013] As used herein, the term "aromatic group" refers to a group obtained by removing one or more hydrogen atoms from an aromatic compound. Specifically, an n-valent aromatic group refers to a group obtained by removing n hydrogen atoms from an aromatic compound. Here, the aromatic compound may be a heteroatom-free aromatic compound composed only of carbon atoms and hydrogen atoms, or a heteroatom-containing aromatic compound composed of carbon atoms, hydrogen atoms, and heteroatoms. As used herein, the term "aromatic compound" refers to a compound containing an aromatic ring. Furthermore, as used herein, the term "aromatic ring" refers to a ring that conforms to the Hückel rule, in which the number of electrons contained in the π-electron system on the ring is 4p + 2 (p is an integer of 1 or greater), and includes monocyclic aromatic rings and fused polycyclic aromatic rings in which two or more monocyclic aromatic rings are fused together. The aromatic ring may be an aromatic carbocycle having only carbon atoms as ring-constituting atoms, or an aromatic heterocycle having, in addition to carbon atoms, heteroatoms such as oxygen, nitrogen, or sulfur atoms as ring-constituting atoms. In this specification, unless otherwise specified, the number of carbon atoms in the aromatic ring is preferably 3 or more, more preferably 4 or more or 5 or more, and even more preferably 6 or more, and the upper limit is preferably 24 or less, more preferably 18 or less or 14 or less, and even more preferably 10 or less. The number of carbon atoms does not include the number of carbon atoms of substituents.

[0014] In this specification, the term "non-volatile components" in relation to the resin composition refers to components constituting the resin composition other than the (G) organic solvent, which will be described later.

[0015] [Resin Composition] The resin composition of the present invention comprises (A) an epoxy resin, (B) a photocurable resin, (C) a resin having a carboxyl group and an ethylenically unsaturated bond, and (D) a photopolymerization initiator. The resin composition of the present invention is characterized in that the content of components that result in a difference in refractive index at a wavelength of 1310 nm of 0.07 or more in the cured products of the (A), (B), and (C) components is less than 10% by mass, where the total of the (A), (B), and (C) components is taken as 100% by mass. The refractive index at a wavelength of 1310 nm in the cured products of each component can be measured using the method described in <Test Example 1: Measurement of refractive index of cured product> below. When an optical waveguide is manufactured using the resin composition of the present invention, an optical waveguide with low optical transmission loss can be reliably obtained.

[0016] Regarding the measurement of the refractive index of the cured product of each component, in detail, (1): When the object to be measured for refractive index is a cured product of a photocurable resin (e.g., (B) photocurable resin, (C) compound having a carboxyl group and an ethylenically unsaturated bond, etc.), the refractive index of the cured product at a wavelength of 1310 nm can be measured by the methods described in (1-1) to (1-5) below. (1-1): 0.2 mass% of a photopolymerization initiator is added to 100 mass% of the photocurable resin to obtain a photocurable resin mixture. (1-2): The photocurable resin mixture (and, if necessary, a resin varnish prepared by dissolving the photocurable resin mixture in an organic solvent) is applied to the flat surface of a member having a flat surface, such as a silicon wafer, to obtain a resin layer with a thickness of 10 μm. (1-3): The formed resin layer is subjected to irradiation with light at a wavelength of 365 nm and an illuminance of 35 mW / cm. ２ and exposure dose 2 J / cm ２(1-4): The exposed resin layer is subjected to a heat treatment at 190°C for 90 minutes in an atmospheric atmosphere to cure the resin layer. (1-5): The cured resin layer obtained is measured at a wavelength of 1310 nm, at room temperature (23°C), and under atmospheric pressure (1 atm). When various conditions such as the type and amount of photopolymerization initiator, (if necessary, the amount of organic solvent used in preparing the resin varnish), the wavelength and exposure dose of light in the exposure treatment, and the heating temperature and heating time in the heat treatment after exposure are changed, the coefficient of variation of the refractive index due to such condition changes is 0.5% or less.

[0017] The photopolymerization initiator used in the step (1-1) can be appropriately selected depending on the type of the photocurable resin. For example, the components described in the section <(D) Photopolymerization initiator> below can be used as the photopolymerization initiator.

[0018] Regarding the measurement of the refractive index of the cured product of each component, more specifically, (2): When the refractive index to be measured is a cured product of a thermosetting resin (e.g., epoxy resin (A)), the refractive index of the cured product at a wavelength of 1310 nm can be measured using the methods described below in (2-1) to (2-4). (2-1): 0.2 mass% of a heat curing accelerator is added to 100 mass% of the thermosetting resin to obtain a thermosetting resin mixture. (2-2): The thermosetting resin mixture (and, if necessary, a resin varnish prepared by dissolving the thermosetting resin mixture in an organic solvent) is applied to the flat surface of a member having a flat surface, such as a silicon wafer, to obtain a resin layer with a thickness of 10 μm. (2-3): The formed resin layer is subjected to a heat treatment at 190°C for 90 minutes in an atmospheric atmosphere to cure the resin layer. (2-4): The cured product of the obtained resin layer is measured at a wavelength of 1310 nm, at room temperature (23°C), and under atmospheric pressure (1 atm). In addition, when various conditions such as the type and amount of the heat curing accelerator, (if necessary, the amount of the organic solvent used in preparing the resin varnish), and the heating temperature and heating time in the heat treatment are changed, the coefficient of variation of the refractive index due to such condition changes is 0.5% or less.

[0019] The heat curing accelerator used in the step (2-1) can be appropriately selected depending on the type of the thermosetting resin. For example, the components described in the section <(E) Heat Curing Accelerator> below can be used as the heat curing accelerator.

[0020] The content X of the component that results in a difference in refractive index at a wavelength of 1,310 nm of 0.07 or more in the cured products of the components (A), (B), and (C) can be calculated by the following steps (i) to (iv): (i) The amount of each of the components (A), (B), and (C) contained in the resin composition of the present invention and the refractive index of the cured products of each of these components are determined. In addition, the component that exhibits the maximum refractive index and the component that exhibits the minimum refractive index are determined. (ii) The refractive index of the component that exhibits the maximum refractive index is calculated as the reference value Y １ and the refractive index is set to Y １ Content X of -0.07 or less １ (mass%), １ = [Refractive index is Y １ (iii): The refractive index of the component showing the smallest refractive index is calculated as follows: [mass of components having a refractive index of −0.07 or less] / [total mass of components (A), (B), and (C)]×100. Here, the relative amount (parts by mass) of each component may be used. ２ and the refractive index is set to Y ２ +0.07 or more content X ２ (mass%), ２ = [Refractive index is Y ２ +0.07 or more] / [total mass of component (A), component (B), and component (C)] × 100. Here, the mass of each component may be expressed as a relative amount (parts by mass). (iv) The content X obtained in (ii) is calculated as follows: １ and the content X obtained in (iii) ２ and the smaller value is designated as the "content X of components that results in a refractive index difference of 0.07 or more at a wavelength of 1,310 nm in the cured products of the components (A), (B), and (C)."

[0021] As described above, in the resin composition of the present invention, the content X of the component that results in a refractive index difference of 0.07 or more at a wavelength of 1310 nm in the cured product of each of the components (A), (B), and (C) is less than 10% by mass. The content X is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less. Alternatively, the content X may be 0% by mass.

[0022] The maximum refractive index of the cured product of each of the components (A), (B), and (C) contained in the resin composition is n ｍａｘ The minimum value of the refractive index is n ｍｉｎ If so, the difference n ｍａｘ -n ｍｉｎ is 0≦n ｍａｘ -n ｍｉｎ It is preferable that the difference in refractive index n ｍａｘ -n ｍｉｎ is more preferably less than 0.06, even more preferably less than 0.05, even more preferably less than 0.04, even more preferably less than 0.03, and even more preferably less than 0.02. ｍａｘ -n ｍｉｎ The lower limit of is not particularly limited, and may be greater than 0 or may be 0.

[0023] The resin composition of the present invention may further contain, as optional components, (E) a heat curing accelerator, (F) other additives, and (G) an organic solvent. Each component contained in the resin composition of the present invention will be described in detail below.

[0024] <(A) Epoxy Resin> The resin composition of the present invention contains (A) an epoxy resin as component (A). The epoxy resin refers to a curable resin having an epoxy group. The (A) epoxy resin may be used alone or in combination of two or more types.

[0025] Examples of epoxy resins include bisphenol-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol novolac-type epoxy resins, phenol novolac-type epoxy resins, tert-butyl-catechol-type epoxy resins, naphthalene-type epoxy resins, naphthol-type epoxy resins, anthracene-type epoxy resins, glycidylamine-type epoxy resins, glycidyl ester-type epoxy resins, cresol novolac-type epoxy resins, biphenyl-type epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexane-type epoxy resins, cyclohexanedimethanol-type epoxy resins, naphthylene ether-type epoxy resins, trimethylol-type epoxy resins, and tetraphenylethane-type epoxy resins. Bisphenol-type epoxy resins refer to epoxy resins having a bisphenol structure, such as bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, and bisphenol AF-type epoxy resins. Biphenyl-type epoxy resin refers to an epoxy resin having a biphenyl structure, where the biphenyl structure may have a substituent such as an alkyl group, an alkoxy group, an aryl group, etc. Therefore, bixylenol-type epoxy resins and biphenylaralkyl-type epoxy resins are also included in biphenyl-type epoxy resins.

[0026] Component (A) preferably contains an epoxy resin having an alicyclic skeleton. Here, "alicyclic skeleton" refers to a non-aromatic ring. The alicyclic skeleton may have a substituent at a substitutable position. The alicyclic skeleton may be a saturated ring consisting of only single bonds, or a non-aromatic unsaturated ring having either a double bond or a triple bond, and among these, the alicyclic skeleton is preferably a saturated ring consisting of only single bonds. The saturated ring may be a saturated carbocyclic ring containing carbon atoms as ring-constituting atoms, or a saturated heterocyclic ring containing heteroatoms such as oxygen atoms, nitrogen atoms, and sulfur atoms as ring-constituting atoms in addition to carbon atoms.

[0027] The saturated ring is preferably a saturated ring having 3 to 18 carbon atoms, more preferably a saturated ring having 5 to 16 carbon atoms. Examples of the saturated ring include monocyclic saturated carbocyclic rings such as monocycloalkane rings such as a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, a cyclononane ring, a cyclodecane ring, a cycloundecane ring, and a cyclododecane ring; bicyclic saturated carbocyclic rings such as a bicyclo[2.2.1]heptane ring (norbornane ring), a bicyclo[4.4.0]decane ring (decalin ring), a bicyclo[5.3.0]decane ring, a bicyclo[4.3.0]nonane ring (hydrindane ring), a bicyclo[3.2.1]octane ring, a bicyclo[5.4.0]undecane ring, a bicyclo[3.3.0]octane ring, and a bicyclo[3.3.1]nonane ring; ２，６ ] decane ring (tetrahydrodicyclopentadiene ring), tricyclo[3.3.1.1 ３，７ ] decane ring (adamantane ring), tricyclo[6.2.1.0 ２，７ ]undecane ring and other saturated tricyclic carbocyclic rings; tetracyclo[6.2.1.1 ３，６ .0 ２，７ tetracyclic saturated carbocyclic rings such as a dodecane ring; pentacyclo[9.2.1.1 ４，７ .0 ２，１ 0.0 ３，８ ] pentadecane ring, pentacyclo[6.5.1.1 ３，６ .0 ２，７ .0 ９，１３ saturated carbocyclic rings such as a five-ring saturated carbocyclic ring such as a pentadecane ring (tetrahydrotricyclopentadiene ring); saturated monocyclic heterocyclic rings such as a pyrrolidine ring, a pyrazolidine ring, an imidazolidine ring, a tetrahydrofuran ring, a 1,3-dioxolane ring, a piperidine ring, a piperazine ring, a tetrahydropyran ring, a 1,3-dioxane ring, a 1,4-dioxane ring, a thiane ring, a 1,3-dithiane ring, a 1,4-dithiane ring, a morpholine ring, a thiomorpholine ring, an oxazolidine ring; saturated bicyclic heterocyclic rings such as a 7-oxabicyclo[4.1.0]heptane ring (1,2-epoxycyclohexane ring), a 1-azabicyclo[2.2.2]octane (quinuclidine ring), a decahydroquinoline ring, a decahydroisoquinoline ring; saturated bicyclic heterocyclic rings such as a 1-azatricyclo[3.3.1.1 ３，７]decane (1-azaadamantane ring), 2-azatricyclo[3.3.1.1 ３，７ ] decane (2-azaadamantane ring) and other saturated heterocyclic rings such as tricyclic saturated heterocyclic rings.

[0028] In component (A), the alicyclic skeleton is preferably a saturated carbocyclic ring, more preferably a monocyclic saturated carbocyclic ring, and even more preferably a cyclohexane ring.

[0029] The epoxy groups in component (A) may be bonded directly to the alicyclic skeleton, or may be bonded via a linker structure having 1 to 100 skeletal atoms selected from the group consisting of carbon atoms, oxygen atoms, sulfur atoms, and nitrogen atoms. Component (A) may also have an epoxy group in which oxygen atoms are attached to two carbon atoms that constitute the alicyclic skeleton (alicyclic epoxy group).

[0030] When component (A) has two or more alicyclic skeletons in one molecule, the alicyclic skeletons may be the same or different.

[0031] Component (A) preferably has two or more epoxy groups per molecule. When the total amount of component (A) is taken as 100% by mass, the proportion of epoxy resins having two or more epoxy groups per molecule is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and is usually 100% by mass or less.

[0032] Epoxy resins include those that are liquid at a temperature of 20°C (hereinafter referred to as "liquid epoxy resins") and those that are solid at a temperature of 20°C (hereinafter referred to as "solid epoxy resins").

[0033] The liquid epoxy resin is preferably a liquid epoxy resin having two or more epoxy groups in one molecule.

[0034] Preferred liquid epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, phenol novolac type epoxy resins, alicyclic epoxy resins such as alicyclic epoxy resins having an ester skeleton, cyclohexane type epoxy resins, cyclohexane dimethanol type epoxy resins, and epoxy resins having a butadiene structure.

[0035] Specific examples of liquid epoxy resins include "HP-4032", "HP-4032-D", and "HP-4032-SS" (naphthalene type epoxy resins) manufactured by DIC Corporation; "828US", "828EL", "828", "825", and "Epicoat 828EL" (bisphenol A type epoxy resins) manufactured by Mitsubishi Chemical Corporation; "807" and "1750" (bisphenol F type epoxy resins) manufactured by Mitsubishi Chemical Corporation; and "152" (phenol novolac type epoxy resin) manufactured by Mitsubishi Chemical Corporation. resins); "630", "630LSD", and "604" (glycidylamine type epoxy resins) manufactured by Mitsubishi Chemical Corporation; "ED-523T" (glycilol type epoxy resin) manufactured by ADEKA Corporation; "EP-3950L" and "EP-3980S" (glycidylamine type epoxy resins) manufactured by ADEKA Corporation; "EP-4088S" (dicyclopentadiene type epoxy resin) manufactured by ADEKA Corporation; "ZX1059" (bisphenol A type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd. a mixture of bisphenol F-type epoxy resin and bisphenol F-type epoxy resin); Nagase ChemteX's "EX-252" and "EX-721" (glycidyl ester type epoxy resin); Daicel's "EHPE3150CE", ENEOS's "THI-DE", Resonac's "Shofree CDMDG", SYMRISE's "LDO" (alicyclic epoxy resin); Daicel's "Celloxide 2021P", "Celloxide 2081P", "Celloxide 2000", and "Celloxide 2010P" (alicyclic epoxy resin). Examples of epoxy resins that can be used include PB-3600 manufactured by Daicel Corporation, JP-100 and JP-200 manufactured by Nippon Soda Co., Ltd. (epoxy resins having a butadiene structure); ZX1658 and ZX1658GS manufactured by Nippon Steel Chemical & Material Co., Ltd. (liquid 1,4-glycidylcyclohexane type epoxy resins); and YX8000 and YX8034 manufactured by Mitsubishi Chemical Corporation (hydrogenated bisphenol A type epoxy resins).

[0036] As the solid epoxy resin, a solid epoxy resin having three or more epoxy groups in one molecule is preferred, and an aromatic solid epoxy resin having three or more epoxy groups in one molecule is more preferred.

[0037] Preferred solid epoxy resins include bixylenol-type epoxy resins, naphthalene-type epoxy resins, naphthalene-type tetrafunctional epoxy resins, cresol novolac-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol-type epoxy resins, biphenyl-type epoxy resins, naphthylene ether-type epoxy resins, anthracene-type epoxy resins, bisphenol A-type epoxy resins, bisphenol AF-type epoxy resins, and tetraphenylethane-type epoxy resins.

[0038] Specific examples of solid epoxy resins include "HP4032H" (naphthalene type epoxy resin) manufactured by DIC Corporation; "HP-4700" and "HP-4710" (naphthalene type tetrafunctional epoxy resins) manufactured by DIC Corporation; "N-690" (cresol novolac type epoxy resin) manufactured by DIC Corporation; "N-695" (cresol novolac type epoxy resin) manufactured by DIC Corporation; "HP-7200", "HP-7200HH", "HP-7200H", and "HP-7200L" (dicyclopentadiene type epoxy resins) manufactured by DIC Corporation; and "EXA-73" manufactured by DIC Corporation. 11", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000" (naphthylene ether type epoxy resin); "EPPN-502H" (trisphenol type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC7000L" (naphthol novolac type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC3000H", "NC3000", "NC3000L", "NC3000FH", "NC3100" (biphenyl type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "ESN475V" manufactured by Nippon Steel Chemical & Material Co., Ltd. "," ESN4100V" (naphthalene-type epoxy resin); "ESN485" (naphthol-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ESN375" (dihydroxynaphthalene-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YX4000H", "YX4000", "YX4000HK", "YL7890" (bixylenol-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YL6121" (biphenyl-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX8800" (anthracene-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX7700" (phenol aralkyl type epoxy resin) manufactured by Hishi Chemical Co., Ltd.; "PG-100" and "CG-500" manufactured by Osaka Gas Chemicals Co., Ltd.; "YX7760" (bisphenol AF type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "1010" (bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "1031S" (tetraphenylethane type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "WHR991S" (phenolphthalimidine type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.;Examples include "EHPE3150" manufactured by Daicel Corporation, "DE-102" and "DE-103" manufactured by ENEOS Corporation, and "DCPD-DE" (alicyclic epoxy resin) manufactured by Japan Material Technology Co., Ltd.

[0039] The resin composition may contain only a liquid epoxy resin as the epoxy resin, only a solid epoxy resin, or a combination of a liquid epoxy resin and a solid epoxy resin. When a liquid epoxy resin and a solid epoxy resin are used in combination, the ratio by mass between them (liquid epoxy resin:solid epoxy resin) is preferably 1:0.01 to 1:50, more preferably 1:0.05 to 1:20, and even more preferably 1:0.1 to 1:10.

[0040] The epoxy equivalent of the epoxy resin is preferably 50 g / eq. to 5,000 g / eq., more preferably 50 g / eq. to 3,000 g / eq., even more preferably 80 g / eq. to 2,000 g / eq., and even more preferably 110 g / eq. to 1,000 g / eq. The epoxy equivalent is the mass of an epoxy resin containing one equivalent of epoxy groups. This epoxy equivalent can be measured in accordance with JIS K7236.

[0041] The weight average molecular weight (Mw) of the epoxy resin is preferably 100 to 5,000, more preferably 250 to 3,000, and even more preferably 400 to 1,500. The weight average molecular weight (Mw) of the epoxy resin can be measured by gel permeation chromatography (GPC) as a polystyrene-equivalent value.

[0042] When the resin composition of the present invention contains a combination of two or more types of epoxy resins as component (A), the cured product of each epoxy resin can be used as the cured product for refractive index measurement.

[0043] The content of component (A) in the resin composition is preferably 1 mass% or more, more preferably 3 mass% or more, and even more preferably 5 mass% or more, relative to 100 mass% of the non-volatile components in the resin composition, and is preferably 30 mass% or less, more preferably 25 mass% or less, and even more preferably 20 mass% or less.

[0044] <(B) Photocurable Resin> The resin composition of the present invention contains a (B) photocurable resin as the component (B). Unless otherwise specified, the (B) photocurable resin does not include those corresponding to the above-mentioned component (A). As the (B) photocurable resin, a resin that can be cured when exposed to light can be used. The (B) photocurable resin may be used alone or in combination of two or more types.

[0045] Examples of the (B) photocurable resin include a resin having an ethylenically unsaturated bond. In this specification, a resin having a carboxyl group and an ethylenically unsaturated bond is classified as component (C). Therefore, the (B) photocurable resin does not include a resin having a carboxyl group and an ethylenically unsaturated bond.

[0046] The term "ethylenically unsaturated bond" refers to a non-aromatic carbon-carbon unsaturated bond, such as a non-aromatic carbon-carbon double bond or carbon-carbon triple bond. Hereinafter, a group having an ethylenically unsaturated bond may be referred to as an "ethylenically unsaturated group." The ethylenically unsaturated group is usually a monovalent group, and examples thereof include a vinyl group, an allyl group, a propargyl group, a butenyl group, an ethynyl group, a phenylethynyl group, a maleimide group, a nadimide group, and a (meth)acryloyl group. From the viewpoint of reactivity in photoradical polymerization, a (meth)acryloyl group is preferred.

[0047] The number of ethylenically unsaturated groups per molecule of component (B) may be 1 or 2 or more. Furthermore, when component (B) contains two or more ethylenically unsaturated groups per molecule, those ethylenically unsaturated groups may be the same or different.

[0048] Examples of the resin having an ethylenically unsaturated bond include (meth)acrylic radical polymerizable resins, styrene radical polymerizable resins, allyl radical polymerizable resins, and maleimide radical polymerizable resins.

[0049] The (meth)acrylic radical polymerizable resin may be a resin having one or more, preferably two or more, acryloyl groups and / or methacryloyl groups in one molecule. Examples of the (meth)acrylic radical polymerizable resin include cyclohexane-1,4-dimethanol di(meth)acrylate, cyclohexane-1,3-dimethanol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, and 1,9-nonane dimethanol di(meth)acrylate. Low molecular weight (molecular weight less than 1000) aliphatic (meth)acrylic acid ester compounds such as diol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, glycerin tri(meth)acrylate, and pentaerythritol tetra(meth)acrylate; dioxane glycol di(meth)acrylate, 3,6-dioxa-1,8-octanediol di(meth)acrylate, ) acrylate, 3,6,9-trioxaundecane-1,11-diol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, ethoxylated bisphenol A di(meth)acrylate, propoxylated bisphenol A di(meth)acrylate, and other low molecular weight (molecular weight less than 1000) ether-containing (meth)acrylic acid ester compounds; low molecular weight (molecular weight less than 1000) isocyanurate-containing (meth)acrylic acid ester compounds such as tris(3-hydroxypropyl)isocyanurate tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, and ethoxylated isocyanuric acid tri(meth)acrylate; and high molecular weight (molecular weight 1000 or more) acrylic acid ester compounds such as (meth)acrylic-modified polyphenylene ether resins.Commercially available (meth)acrylic radical polymerizable resins include, for example, NK ester series such as "A-DOG" (dioxane glycol diacrylate), "4G", "9G", "14G", "23G", "DCP", "TMPT", "A-TMPT", and "A-NOD-N" manufactured by Shin-Nakamura Chemical Co., Ltd.; "DCP-A" (tricyclodecane dimethanol diacrylate), "DCP" (tricyclodecane dimethanol dimethacrylate), and "BPE-1300N" (ethoxylated bisphenol A dimethacrylate) manufactured by Kyoeisha Chemical Co., Ltd.; and "KAYARAD R-684" (tricyclodecane dimethanol diacrylate) and "KAYARAD Examples of such acrylates include "R-604" (dioxane glycol diacrylate), "DPHA" (dipentaerythritol hexaacrylate); "SA9000" and "SA9000-111" (methacrylic modified polyphenylene ether) manufactured by SABIC; "SR209", "CN2301", and "CN2304" manufactured by Sartomer Japan; "EA-0200", "EA-F5710", and "EA-300" manufactured by Osaka Gas Chemicals Co., Ltd.; "1-NMA" and "DABP" manufactured by JFE Chemical Corporation; "M-211B" and "M-208" manufactured by Toagosei Co., Ltd.; "EBECRYL600" manufactured by Daicel-Allnex Corporation; and "A-BPML" manufactured by Shin-Nakamura Chemical Co., Ltd.

[0050] The styrene-based radical polymerizable resin may be a resin having one or more, preferably two or more, vinyl groups directly bonded to an aromatic carbon atom per molecule. Examples of the styrene-based radical polymerizable resin include low-molecular-weight (molecular-weight less than 1000) styrene-based compounds such as divinylbenzene, 2,4-divinyltoluene, 2,6-divinylnaphthalene, 1,4-divinylnaphthalene, 4,4'-divinylbiphenyl, 1,2-bis(4-vinylphenyl)ethane, 2,2-bis(4-vinylphenyl)propane, and bis(4-vinylphenyl)ether; and high-molecular-weight (molecular-weight 1000 or more) styrene-based compounds such as vinylbenzyl-modified polyphenylene ether resin and styrene-divinylbenzene copolymer. Commercially available styrene-based radical polymerizable resins include, for example, "ODV-XET (X03)", "ODV-XET (X04)", and "ODV-XET (X05)" (styrene-divinylbenzene copolymers) manufactured by Nippon Steel Chemical & Material Co., Ltd.; and "OPE-2St 1200" and "OPE-2St 2200" (vinylbenzyl-modified polyphenylene ether resins) manufactured by Mitsubishi Gas Chemical Company, Inc.

[0051] The allyl radical polymerizable resin may be a resin having one or more, preferably two or more, allyl groups in one molecule. Examples of allyl radical polymerizable resins include aromatic carboxylic acid allyl ester compounds such as diallyl diphenate, triallyl trimellitate, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, 2,6-naphthalenedicarboxylic acid diallyl, and 2,3-naphthalenecarboxylic acid diallyl ester compounds; isocyanuric acid allyl ester compounds such as 1,3,5-triallyl isocyanurate and 1,3-diallyl-5-glycidyl isocyanurate; epoxy-containing aromatic allyl compounds such as 2,2-bis[3-allyl-4-(glycidyloxy)phenyl]propane; benzoxazine-containing aromatic allyl compounds such as bis[3-allyl-4-(3,4-dihydro-2H-1,3-benzoxazin-3-yl)phenyl]methane; ether-containing aromatic allyl compounds such as 1,3,5-triallyl ether benzene; and allyl silane compounds such as diallyldiphenylsilane. Commercially available allyl radical polymerizable resins include "TAIC" (1,3,5-triallyl isocyanurate) manufactured by Nippon Kasei Chemical Industry Co., Ltd.; "DAD" (diallyl diphenate) manufactured by Nisshoku Techno Fine Chemical Co., Ltd.; "TRIAM-705" (triallyl trimellitate) manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.; "DAND" (2,3-diallyl naphthalenecarboxylate) manufactured by Nisshoku Techno Fine Chemical Co., Ltd.; "ALP-d" (bis[3-allyl-4-(3,4-dihydro-2H-1,3-benzoxazin-3-yl)phenyl]methane) and "DA-MGIC" (1,3-diallyl-5-glycidyl isocyanurate) manufactured by Shikoku Chemical Industry Co., Ltd.; and "RE-810NM" (2,2-bis[3-allyl-4-(glycidyloxy)phenyl]propane) manufactured by Nippon Kayaku Co., Ltd.; and the like.

[0052] As the maleimide radical polymerizable resin, a resin having one or more, preferably two or more, maleimide groups in one molecule can be used. The maleimide radical polymerizable resin may be an aromatic maleimide resin having a maleimide group directly bonded to an aromatic ring, or an aliphatic maleimide resin having no maleimide group directly bonded to an aromatic ring. Commercially available maleimide radical polymerizable resins include, for example, "SLK-2600" manufactured by Shin-Etsu Chemical Co., Ltd.; Examples of the maleimide resin include "BMI-1500," "BMI-1700," "BMI-3000J," "BMI-689," and "BMI-2500" (dimer diamine structure-containing maleimide compounds) and "BMI-6100" (aromatic maleimide compound) manufactured by Nippon Kayaku Co., Ltd.; "MIR-5000-60T" and "MIR-3000-70MT" (biphenylaralkyl maleimide compounds) manufactured by Nippon Kayaku Co., Ltd.; "BMI-70" and "BMI-80" manufactured by K.I. Chemical Industry Co., Ltd.; and "BMI-2300" and "BMI-TMH" manufactured by Daiwa Kasei Kogyo Co., Ltd. Examples of the maleimide-based radical polymerizable resin include the maleimide resin (indane ring skeleton-containing maleimide compound) disclosed in the Japan Institute of Invention and Innovation Disclosure Technical Bulletin No. 2020-500211.

[0053] The ethylenically unsaturated group equivalent of component (B) is preferably 20 g / eq. to 3,000 g / eq., more preferably 50 g / eq. to 2,500 g / eq., even more preferably 70 g / eq. to 2,000 g / eq., and still more preferably 90 g / eq. to 1,500 g / eq. The ethylenically unsaturated group equivalent of component (B) represents the mass (molecular weight) of component (B) per equivalent of the ethylenically unsaturated group.

[0054] The weight average molecular weight (Mw) of component (B) is preferably 500 or more, more preferably 750 or more, and even more preferably 900 or more. The upper limit of the weight average molecular weight (Mw) of component (B) is preferably 50,000 or less, more preferably 10,000 or less, and even more preferably 5,000 or less. The weight average molecular weight (Mw) of component (B) can be measured as a polystyrene-equivalent value by gel permeation chromatography (GPC).

[0055] When the resin composition of the present invention contains a combination of two or more photocurable resins as component (B), the cured product of each photocurable resin can be used for refractive index measurement.

[0056] The content of component (B) in the resin composition is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, relative to 100% by mass of the non-volatile components in the resin composition, and is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 45% by mass or less.

[0057] <(C) Resin Having a Carboxyl Group and an Ethylenically Unsaturated Bond> The resin composition of the present invention contains (C) a resin having a carboxyl group and an ethylenically unsaturated bond as component (C). Unless otherwise specified, the (C) resin having a carboxyl group and an ethylenically unsaturated bond does not include those corresponding to the above-mentioned components (A) and (B). Resin compositions containing component (C) are soluble in alkaline developers (e.g., 1% by mass aqueous sodium carbonate solution) and can be developed in an alkaline environment. The (C) resin having a carboxyl group and an ethylenically unsaturated bond may be used singly or in combination of two or more.

[0058] One embodiment of the component (C) is an acid-modified epoxy (meth)acrylate resin.

[0059] In one embodiment, the acid-modified epoxy (meth)acrylate resin may be capable of photoradical polymerization because it has a (meth)acryloyl group. The number of (meth)acryloyl groups per molecule of the acid-modified epoxy (meth)acrylate resin may be one or two or more.

[0060] The acid-modified epoxy (meth)acrylate resin preferably has both a (meth)acryloyl group and a carboxyl group, and is capable of photoradical polymerization and alkali development.

[0061] The acid-modified epoxy(meth)acrylate resin can be produced by acid-modifying an epoxy(meth)acrylate resin by a known method, for example, by reacting an epoxy resin with acrylic acid or methacrylic acid.

[0062] The epoxy resin for producing the epoxy (meth)acrylate resin is not particularly limited as long as it is a compound having an epoxy group in the molecule, and examples thereof include bisphenol-type epoxy resins such as bisphenol A-type epoxy resins, hydrogenated bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, hydrogenated bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, and modified bisphenol F-type epoxy resins obtained by reacting bisphenol F-type epoxy resins with epichlorohydrin to modify them to have three or more functional groups; biphenol-type epoxy resins such as biphenol-type epoxy resins and tetramethylbiphenol-type epoxy resins; novolac-type epoxy resins such as phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, bisphenol A-type novolac-type epoxy resins, and alkylphenol novolac-type epoxy resins; fluorine-containing epoxy resins such as bisphenol AF-type epoxy resins and perfluoroalkyl-type epoxy resins; naphthalene-type epoxy resins, dihydroxynaphthalene-type epoxy resins, polyhydroxybinaphthalene-type epoxy resins, naphthol-type epoxy resins, naphtholaralkyl-type epoxy resins, biphenol-type epoxy resins, and the like. Epoxy resins having a naphthalene skeleton (naphthalene skeleton-containing epoxy resins) such as naphthol-type epoxy resins, naphthylene ether-type epoxy resins, naphthol novolac-type epoxy resins, and naphthalene-type epoxy resins obtained by the condensation reaction of polyhydroxynaphthalene with aldehydes; aralkyl-type epoxy resins; bixylenol-type epoxy resins; dicyclopentadiene-type epoxy resins; trisphenol-type epoxy resins; tert-butyl-catechol-type epoxy resins; and epoxy resins containing a condensed ring skeleton such as anthracene-type epoxy resins; glycerin diglycidylamine-type epoxy resins; glycidyl ester-type epoxy resins; biphenyl-type epoxy resins; linear aliphatic epoxy resins; epoxy resins having a butadiene structure; alicyclic epoxy resins; heterocyclic epoxy resins; spiro ring-containing epoxy resins; cyclohexanedimethanol-type epoxy resins; trimethylol-type epoxy resins; tetraphenylethane-type epoxy resins; glycidyl group-containing acrylic resins such as polyglycidyl (meth)acrylate and copolymers of glycidyl methacrylate and acrylic esters; fluorene-type epoxy resins; halogenated epoxy resins;Epoxy resins having a cardo structure are also included.

[0063] From the viewpoint of achieving the effects of the present invention more significantly, the epoxy resin used to produce the epoxy (meth)acrylate resin is preferably an epoxy resin containing an aromatic skeleton. Here, the term "aromatic skeleton" encompasses polycyclic aromatics and aromatic heterocycles. Among these, the epoxy resin used to produce the epoxy (meth)acrylate resin is preferably any of an aralkyl epoxy resin, a naphthol aralkyl epoxy resin, and an epoxy resin having a cardo structure, with a naphthol aralkyl epoxy resin being more preferred. A cardo structure refers to a structure in which two aromatic rings are bonded to a carbon atom within the ring.

[0064] In one embodiment, the acid-modified epoxy (meth)acrylate resin preferably includes an acid-modified epoxy (meth)acrylate resin having a skeleton selected from an aralkyl skeleton, a naphthol aralkyl skeleton, and a cardo skeleton, and particularly preferably includes an acid-modified epoxy (meth)acrylate resin having a naphthol aralkyl skeleton.

[0065] In one embodiment, the acid-modified epoxy (meth)acrylate resin preferably contains a resin selected from an acid-modified epoxy (meth)acrylate resin in which a hydroxyl group of an epoxy (meth)acrylate resin has been esterified (hereinafter referred to as an "ester-type acid-modified epoxy (meth)acrylate resin") and an acid-modified epoxy (meth)acrylate resin in which a hydroxyl group of an epoxy (meth)acrylate resin has been urethanized (hereinafter referred to as a "urethane-type acid-modified epoxy (meth)acrylate resin"), and particularly preferably contains an ester-type acid-modified epoxy (meth)acrylate resin.

[0066] The ester-type acid-modified epoxy(meth)acrylate resin can be produced, for example, by reacting an epoxy(meth)acrylate resin with an acid anhydride. The ester-type acid-modified epoxy(meth)acrylate resin may be used alone or in combination of two or more.

[0067] Examples of acid anhydrides include maleic anhydride, succinic anhydride, itaconic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and benzophenonetetracarboxylic dianhydride, and these may be used alone or in combination of two or more. Among these, succinic anhydride and tetrahydrophthalic anhydride are preferred, and tetrahydrophthalic anhydride is more preferred.

[0068] The ester-type acid-modified epoxy(meth)acrylate resin preferably contains a resin selected from a cresol novolac skeleton-containing ester-type acid-modified epoxy(meth)acrylate resin, a bisphenol A skeleton-containing ester-type acid-modified epoxy(meth)acrylate resin, a bisphenol F skeleton-containing ester-type acid-modified epoxy(meth)acrylate resin, a biphenyl skeleton-containing acid ester-type modified epoxy(meth)acrylate resin, and a naphthol aralkyl skeleton-containing ester-type acid-modified epoxy(meth)acrylate resin.

[0069] The ester-type acid-modified epoxy (meth)acrylate resin can be synthesized by a known method, but commercially available products may also be used. Specific examples of commercially available products include "CCR-1373H" (cresol novolac skeleton-containing acid-modified epoxy acrylate resin), "ZCR-8001H" (biphenyl skeleton-containing acid-modified epoxy acrylate resin), "ZCR-1569H" (biphenyl skeleton-containing acid-modified epoxy acrylate resin), "CCR-1171H" (cresol novolac skeleton-containing acid-modified epoxy acrylate resin), "ZCR-1797H", "ZCR-1761H" (biphenyl skeleton-containing acid-modified epoxy acrylate resin), "ZAR-2000", and "ZAR-2001H" (bisphenol A), all manufactured by Nippon Kayaku Co., Ltd. Examples of such resins include "ZFR-1491H" and "ZFR-1533H" (acid-modified epoxy acrylate resin containing a bisphenol F skeleton), "PCR-1173H" (acid-modified epoxy acrylate resin containing a phenol novolac skeleton), and "CCR-1179" (acid-modified epoxy acrylate resin containing a cresol novolac skeleton); "PR-300CP" (cresol novolac acid-modified epoxy acrylate resin) manufactured by Resonac Corporation; and "UE-9350" (cresol novolac acid-modified epoxy acrylate resin) manufactured by DIC Corporation.

[0070] The urethane-type acid-modified epoxy(meth)acrylate resin can be produced, for example, by reacting an epoxy(meth)acrylate resin with a diisocyanate compound and a carboxyl group-containing diol compound. The urethane-type acid-modified epoxy(meth)acrylate resin may be used alone or in combination of two or more.

[0071] Examples of diisocyanate compounds include aromatic diisocyanate compounds such as phenylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, diphenyl diisocyanate, and naphthalene diisocyanate; and aliphatic diisocyanate compounds such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, allylene sulfone ether diisocyanate, allyl cyanide diisocyanate, N-acyl diisocyanate, trimethylhexamethylene diisocyanate, and 1,3-bis(isocyanatemethyl)cyclohexane.

[0072] Examples of the carboxyl group-containing diol compound include dimethylolpropionic acid, dimethylolbutanoic acid, and dimethylolnonanoic acid.

[0073] The urethane-type acid-modified epoxy(meth)acrylate resin preferably contains a resin selected from a cresol novolac skeleton-containing urethane-type acid-modified epoxy(meth)acrylate resin, a bisphenol A skeleton-containing urethane-type acid-modified epoxy(meth)acrylate resin, a bisphenol F skeleton-containing urethane-type acid-modified epoxy(meth)acrylate resin, a biphenyl skeleton-containing acid-urethane-type modified epoxy(meth)acrylate resin, and a naphthol aralkyl skeleton-containing urethane-type acid-modified epoxy(meth)acrylate resin.

[0074] The urethane-type acid-modified epoxy (meth)acrylate resin can be synthesized by a known synthesis method, but commercially available products may also be used. Examples of known synthesis methods include the method described in JP 2016-199719 A. Specific examples of commercially available products include "UXE-3024," "UXE-3011," "UXE-3012," and "UXE-3024" manufactured by Nippon Kayaku Co., Ltd.

[0075] Another embodiment of component (C) is an unsaturated modified (meth)acrylic resin obtained by reacting an ethylenically unsaturated group-containing epoxy compound with a (meth)acrylic resin having structural units obtained by polymerizing acrylic acid and / or methacrylic acid to introduce an ethylenically unsaturated group. Examples of ethylenically unsaturated group-containing epoxy compounds include glycidyl methacrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, and 3,4-epoxycyclohexylmethyl (meth)acrylate. Furthermore, it is also possible to react an acid anhydride with the hydroxyl group generated during the introduction of the unsaturated group. The acid anhydride may be the same as the acid anhydride described above.

[0076] Such unsaturated acid-modified (meth)acrylate resins may be commercially available products, and specific examples include "RA-4101" manufactured by Negami Chemical Industrial Co., Ltd.; "SPC-1000" and "SPC-3000" manufactured by Resonac Corporation; and "Cyclomer P(ACA)Z250," "Cyclomer P(ACA)Z251," "Cyclomer P(ACA)Z254," "Cyclomer P(ACA)Z300," and "Cyclomer P(ACA)Z320" manufactured by Daicel-Allnex Corporation.

[0077] From the viewpoint of improving the alkaline developability of the resin composition, the acid value of component (C) is preferably 0.1 mgKOH / g or more, more preferably 0.5 mgKOH / g or more, even more preferably 1 mgKOH / g or more, 10 mgKOH / g or more, still more preferably 20 mgKOH / g or more, 30 mgKOH / g or more, 40 mgKOH / g or more, or 50 mgKOH / g or more. The upper limit of the acid value of component (C) is preferably 200 mgKOH / g or less, more preferably 150 mgKOH / g or less, even more preferably 120 mgKOH / g or less, or 100 mgKOH / g or less.

[0078] The weight average molecular weight (Mw) of component (C) is preferably 500 or more, more preferably 750 or more, and even more preferably 900 or more. The upper limit of the weight average molecular weight (Mw) of component (C) is preferably 100,000 or less, more preferably 50,000 or less, and even more preferably 30,000 or less or 25,000 or less. The weight average molecular weight (Mw) of component (C) can be measured as a polystyrene-equivalent value by gel permeation chromatography (GPC).

[0079] When the resin composition of the present invention contains a combination of two or more types of resins having a carboxyl group and an ethylenically unsaturated bond as component (C), each of the resins having a carboxyl group and an ethylenically unsaturated bond can be used as a cured product for refractive index measurement.

[0080] The content of component (C) in the resin composition is preferably 20% by mass or more and 90% by mass or less, relative to 100% by mass of the total of components (A), (B), and (C). In detail, the content of component (C) is preferably 20% by mass or more, more preferably 30% by mass or more, and even more preferably 35% by mass or more, relative to 100% by mass of the total of components (A), (B), and (C), and is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less.

[0081] The content of component (C) in the resin composition is preferably 25% by mass or more, more preferably 35% by mass or more, and even more preferably 40% by mass or more, relative to 100% by mass of the non-volatile components in the resin composition, and is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less.

[0082] <(D) Photopolymerization initiator> The resin composition of the present invention contains a (D) photopolymerization initiator as the (D) component. The (D) photopolymerization initiator does not include those corresponding to the above-mentioned components (A) to (C), unless otherwise specified. The (D) photopolymerization initiator may be used alone or in combination of two or more types.

[0083] The photopolymerization initiator (D) may be a photoradical generator and / or a photoacid generator. Of these, the component (D) preferably contains a photoradical generator.

[0084] The photoradical generator may be a compound capable of generating radicals upon exposure to actinic rays. One type of photoradical generator may be used alone, or two or more types may be used in combination.

[0085] Examples of the photoradical generator include an oxime ester-based photopolymerization initiator, an α-aminoketone-based photopolymerization initiator, a phosphine oxide-based photopolymerization initiator, an α-hydroxyketone-based photopolymerization initiator, a benzoin-based photopolymerization initiator, a benzyl ketal-based photopolymerization initiator, and an acylphosphine-based photopolymerization initiator.

[0086] Examples of the oxime ester photopolymerization initiator include 2-(benzoyloxyimino)-1-[4-(phenylthio)phenyl]octan-1-one (OXE01), [1-[9-ethyl-6-(2-methylbenzoyl)carbazol-3-yl]ethylideneamino]acetate (OXE02), ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime), and the like.

[0087] Examples of the α-aminoketone photopolymerization initiator include 2-methyl-1-phenyl-2-morpholinopropan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-methyl-1-(4-hexylphenyl)-2-morpholinopropan-1-one, 2-ethyl-2-(dimethylamino)-1-(4-morpholinophenyl)butan-1-one, 2-benzyl-2-(dimethylamino)-1-(4-morpholinophenyl)butan-1-one, 2-(dimethylamino)-2-(4-methylphenylmethyl)-1-(4-morpholinophenyl)butan-1-one, 2-methyl-1-(9,9-dibutylfluoren-2-yl)-2-morpholinopropan-1-one, and compounds having a structure represented by the following formula (D3-1):

[0088]

[0089] (In formula (D3-1), R Ｘ is a group represented by the following formula (D3-2); and d represents an integer of 1 to 10.

[0090]

[0091] (In formula (D3-2), * represents a bond.)

[0092] Examples of the phosphine oxide photopolymerization initiator include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, and polyoxyethylene glycerin ether tris[phenyl(2,4,6-trimethylbenzoyl)phosphinate] (Polymeric TPO-L).

[0093] Examples of the phosphine oxide photopolymerization initiator include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, and polyoxyethylene glycerin ether tris[phenyl(2,4,6-trimethylbenzoyl)phosphinate] (Polymeric TPO-L).

[0094] Examples of the α-hydroxyketone photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropanone, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methylpropanone, and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one.

[0095] Examples of benzoin-based photopolymerization initiators include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, etc. Examples of benzil ketal-based photopolymerization initiators include 2,2-dimethoxy-2-phenylacetophenone, etc.

[0096] Examples of the acylphosphine photopolymerization initiator include bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide and compounds having a structure represented by the following formula (D4-1).

[0097]

[0098] (In formula (D4-1), R Ｙ is a group represented by the following formula (D4-2); a, b, and c each independently represent an integer of 1 to 10.

[0099]

[0100] (In formula (D4-2), * represents a bond.)

[0101] Commercially available photoradical generators can be used, including, for example, "Irgacure-OXE01," "Irgacure-OXE02," "Irgacure-OXE04," and "Irgacure TPO" manufactured by BASF; "Omnirad 907," "Omnirad 369," "Omnirad 379," "Omnirad 379EG," "Omnirad 819," "Omnirad TPO," "Omnipol 910," "Omnipol TP," and "Omnipol 9210" manufactured by IGM; and "N-1919" manufactured by ADEKA Corporation.

[0102] The photoacid generator may be a compound capable of generating an acid upon irradiation with actinic rays, such as an oxime ester compound, a halogen-containing compound, an onium salt compound, a diazoketone compound, a sulfone compound, a sulfonic acid compound, a sulfonimide compound, a diazomethane compound, or a diazoquinone compound.

[0103] Specific examples of oxime ester compounds that can be suitably used as photoacid generators include benzeneacetonitrile, 2-methyl-α-[2-[[(propylsulfonyl)oxy]imino]-3(2H)-thienylidene], benzeneacetonitrile, 2-methyl-α-[2-[[[(4-methylphenyl)sulfonyl]oxy]imino]-3(2H)-thienylidene], etc. Commercially available products include "PAG103," "PAG121," "PAG169," and "PAG203" manufactured by BASF.

[0104] Examples of halogen-containing compounds that can be used as photoacid generators include haloalkyl group-containing hydrocarbon compounds, haloalkyl group-containing heterocyclic compounds, etc. Specific preferred examples of the halogen-containing compound include 2-[2-(furan-2-yl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(5-methylfuran-2-yl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, 2-(methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(4-methoxyphenyl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(3,4-dimethoxyphenyl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine,

[0039] Examples of s-triazine derivatives include s-triazine derivatives such as phenyl-bis(trichloromethyl)-s-triazine, 4-methoxyphenyl-bis(trichloromethyl)-s-triazine, styryl-bis(trichloromethyl)-s-triazine, and naphthyl-bis(trichloromethyl)-s-triazine.

[0105] Specific examples of the halogen-containing compound include "TFE-triazine," "TME-triazine," "MP-triazine," "MOP-triazine," and "dimethoxytriazine" (halogen-containing compound-based photoacid generators having a triazine skeleton), all manufactured by Sanwa Chemical Co., Ltd.

[0106] Examples of onium salt compounds that can be suitably used as photoacid generators include iodonium salts, sulfonium salts, phosphonium salts, diazonium salts, and pyridinium salts. Specific preferred examples of the onium salt compound include tris(4-methylphenyl)sulfonium trifluoromethanesulfonate, tris(4-methylphenyl)sulfonium hexafluorophosphonate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium p-toluenesulfonate, diphenyliodonium hexafluoroantimonate, diphenyliodonium hexafluorophosphate, diphenyliodonium tetrafluoroborate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium p-toluenesulfonate, triphenylsulfonium hexafluoroantimonate, 4-tert-butylphenyl.diphenylsulfonium trifluoromethanesulfonate, 4-tert-butylphenyl.diphenylsulfonium p-toluenesulfonate, and 4,7-di-n-butoxynaphthyltetrahydrothiophenium trifluoromethanesulfonate.

[0107] Commercially available onium salt compounds can be used, and examples of commercially available products include "TS-01" and "TS-91" manufactured by Sanwa Chemical Co., Ltd.; "CPI-110A," "CPI-210S," "HS-1," "LW-S1," "IK-1," and "CPI-310B" manufactured by San-Apro Ltd.; and "SI-110L," "SI-180L," and "SI-100L" manufactured by Sanshin Chemical Industry Co., Ltd.

[0108] Examples of sulfonic acid compounds that can be suitably used as photoacid generators include alkylsulfonate esters, haloalkylsulfonate esters, arylsulfonate esters, iminosulfonates, etc. Specific examples of suitable sulfonic acid compounds include benzoin tosylate, pyrogallol tristrifluoromethanesulfonate, o-nitrobenzyl trifluoromethanesulfonate, o-nitrobenzyl p-toluenesulfonate, etc.

[0109] Specific examples of sulfonimide compounds that can be suitably used as a photoacid generator include N-(trifluoromethylsulfonyloxy)succinimide, N-(trifluoromethylsulfonyloxy)phthalimide, N-(trifluoromethylsulfonyloxy)diphenylmaleimide, N-(trifluoromethylsulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide, and N-(trifluoromethylsulfonyloxy)naphthylimide.

[0110] Specific examples of diazomethane compounds that can be suitably used as photoacid generators include bis(trifluoromethylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(phenylsulfonyl)diazomethane, etc. Commercially available diazomethane compounds can be used.

[0111] Examples of diazoketone compounds, sulfone compounds, and diazoquinone compounds that can be suitably used as photoacid generators include those described in JP 2018-169627 A, WO 2010 / 134207 A, WO 2014 / 069202 A, JP 2020-101813 A, and WO 2018 / 232214 A.

[0112] The content of component (D) in the resin composition is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, relative to 100% by mass of the non-volatile components in the resin composition, and is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 6% by mass or less.

[0113] <(E) Heat Curing Accelerator> The resin composition of the present invention may contain a (E) heat curing accelerator as an optional component. Unless otherwise specified, the (E) heat curing accelerator as component (E) does not include those corresponding to the above-mentioned components (A) to (D). The (E) heat curing accelerator functions, for example, as a catalyst or thermal radical generator, thereby accelerating the curing reaction of the resin (A) such as the epoxy resin, thereby accelerating the thermal curing of the resin composition. When the resin composition contains component (E), one type of (E) heat curing accelerator may be used alone, or two or more types may be used in combination.

[0114] Examples of the (E) thermal curing accelerator include phosphorus-based curing accelerators, urea-based curing accelerators, guanidine-based curing accelerators, imidazole-based curing accelerators, metal-based curing accelerators, and amine-based curing accelerators. Furthermore, a thermal radical generator may be used as the (E) thermal curing accelerator.

[0115] Examples of the phosphorus-based curing accelerator include aliphatic phosphonium salts such as tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium laurate, bis(tetrabutylphosphonium)pyromellitate, tetrabutylphosphonium hydrogenhexahydrophthalate, tetrabutylphosphonium 2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenolate, and di-tert-butyldimethylphosphonium tetraphenylborate; methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, propyltriphenylphosphonium bromide, butyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, tetraphenylphosphonium bromide, p-tolyltriphenylphosphonium tetra-p-tolylborate, and tetraphenylphosphonium bromide. aromatic phosphonium salts such as tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, triphenylethylphosphonium tetraphenylborate, tris(3-methylphenyl)ethylphosphonium tetraphenylborate, tris(2-methoxyphenyl)ethylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate; aromatic phosphine-borane complexes such as triphenylphosphine-triphenylborane; aromatic phosphine-quinone addition products such as triphenylphosphine-p-benzoquinone addition products; aliphatic phosphines such as tributylphosphine, tri-tert-butylphosphine, trioctylphosphine, di-tert-butyl(2-butenyl)phosphine, di-tert-butyl(3-methyl-2-butenyl)phosphine, and tricyclohexylphosphine;Dibutylphenylphosphine, di-tert-butylphenylphosphine, methyldiphenylphosphine, ethyldiphenylphosphine, butyldiphenylphosphine, diphenylcyclohexylphosphine, triphenylphosphine, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tris(4-ethylphenyl)phosphine, tris(4-propylphenyl)phosphine, tris(4-isopropylphenyl)phosphine, tris(4-butylphenyl)phosphine, tris(4-tert-butylphenyl)phosphine, tris(2,4-dimethylphenyl)phosphine, tris(2,5-dimethylphenyl)phosphine, tris(2,6-dimethylphenyl)phosphine aromatic phosphines such as phenylphosphine, tris(3,5-dimethylphenyl)phosphine, tris(2,4,6-trimethylphenyl)phosphine, tris(2,6-dimethyl-4-ethoxyphenyl)phosphine, tris(2-methoxyphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(4-ethoxyphenyl)phosphine, tris(4-tert-butoxyphenyl)phosphine, diphenyl-2-pyridylphosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,2-bis(diphenylphosphino)acetylene, and 2,2′-bis(diphenylphosphino)diphenyl ether;

[0116] Examples of the urea-based curing accelerator include 1,1-dimethylurea; aliphatic dimethylureas such as 1,1,3-trimethylurea, 3-ethyl-1,1-dimethylurea, 3-cyclohexyl-1,1-dimethylurea, and 3-cyclooctyl-1,1-dimethylurea; 3-phenyl-1,1-dimethylurea, 3-(4-chlorophenyl)-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea, 3-(2-methylphenyl)-1,1-dimethylurea, 3-(4-methylphenyl)-1,1-dimethylurea, and 3-(3,4-dimethylphenyl)-1,1-dimethylurea. aromatic dimethylureas such as N,N-(1,4-phenylene)bis(N',N'-dimethylurea), N,N-(4-methyl-1,3-phenylene)bis(N',N'-dimethylurea) [toluene bisdimethylurea], and the like.

[0117] Examples of guanidine curing accelerators include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, 1-phenylbiguanide, and 1-(o-tolyl)biguanide.

[0118] Examples of the imidazole curing accelerator include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, and 1-benzyl-2-methylimidazole. Phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl -(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct imidazole compounds such as 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, and 2-phenylimidazoline, as well as adducts of imidazole compounds with epoxy resins. Commercially available imidazole curing accelerators include, for example, "1B2PZ", "2E4MZ", "2MZA-PW", "2MZ-OK", "2MA-OK", "2MA-OK-PW", "2PHZ", "2PHZ-PW", "Cl1Z", "Cl1Z-CN", "Cl1Z-CNS", and "C11Z-A" manufactured by Shikoku Chemicals Corporation; and "P200-H50" manufactured by Mitsubishi Chemical Corporation.

[0119] Examples of metal-based curing accelerators include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include organic cobalt complexes such as cobalt(II) acetylacetonate and cobalt(III) acetylacetonate, organic copper complexes such as copper(II) acetylacetonate, organic zinc complexes such as zinc(II) acetylacetonate, organic iron complexes such as iron(III) acetylacetonate, organic nickel complexes such as nickel(II) acetylacetonate, and organic manganese complexes such as manganese(II) acetylacetonate. Examples of organometallic salts include zinc octoate, tin octoate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

[0120] Examples of the amine curing accelerator include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclo(5,4,0)-undecene, etc. Commercially available amine curing accelerators may be used, such as "MY-25" manufactured by Ajinomoto Fine-Techno Co., Inc.

[0121] Examples of the thermal radical generator include peroxide-based radical polymerization initiators and azo-based radical polymerization initiators.

[0122] Examples of the peroxide radical polymerization initiator include hydroperoxide compounds such as 1,1,3,3-tetramethylbutyl hydroperoxide; dialkyl peroxide compounds such as tert-butylcumyl peroxide, di-tert-butyl peroxide, di-tert-hexyl peroxide, di-tert-amyl peroxide, dicumyl peroxide, 1,4-bis(1-tert-butylperoxy-1-methylethyl)benzene, and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; and diacid compounds such as dilauroyl peroxide, didecanoyl peroxide, dicyclohexyl peroxydicarbonate, and bis(4-tert-butylcyclohexyl)peroxydicarbonate. peroxide compounds; and peroxyester compounds such as tert-butyl peroxyacetate, tert-butyl peroxybenzoate, tert-butylperoxyisopropyl monocarbonate, tert-butylperoxy-2-ethylhexanoate, tert-butylperoxyneodecanoate, tert-hexylperoxyisopropyl monocarbonate, tert-butyl peroxylaurate, (1,1-dimethylpropyl) 2-ethylperhexanoate, tert-butyl 2-ethylperhexanoate, tert-butyl 3,5,5-trimethylperhexanoate, tert-butylperoxy-2-ethylhexyl monocarbonate, and tert-butylperoxymaleic acid.

[0123] Examples of the azo radical polymerization initiator include azonitrile compounds such as 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 1-[(1-cyano-1-methylethyl)azo]formamide, and 2-phenylazo-4-methoxy-2,4-dimethyl-valeronitrile; 2,2'-azobis[2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide], 2,2'-azobis[2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide], and 2,2'-azobis[2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide]. azoamide compounds such as 2,2'-azobis[2-methyl-N-[2-(1-hydroxybutyl)]-propionamide], 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)-propionamide], 2,2'-azobis(2-methylpropionamide) dihydrate, 2,2'-azobis[N-(2-propenyl)-2-methylpropionamide], 2,2'-azobis(N-butyl-2-methylpropionamide), and 2,2'-azobis(N-cyclohexyl-2-methylpropionamide); alkyl azo compounds such as 2,2'-azobis(2,4,4-trimethylpentane) and 2,2'-azobis(2-methylpropane); and the like.

[0124] Examples of commercially available thermal radical generators include "Perbutyl C," "Perbutyl A," "Perbutyl P," "Perbutyl L," "Perbutyl O," "Perbutyl ND," "Perbutyl Z," "Perbutyl I," "Percumyl P," "Percumyl D," "Perhexyl D," "Perhexyl A," "Perhexyl I," "Perhexyl Z," "Perhexyl ND," "Perhexyl O," and "Perhexyl PV," all manufactured by NOF Corporation; and "Luperox DTA" manufactured by Arkema Yoshitomi Co., Ltd.

[0125] When the resin composition contains a heat curing accelerator (E), the content of the component (E) in the resin composition is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.3% by mass or more, relative to 100% by mass of the non-volatile components in the resin composition, and is preferably 3% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less.

[0126] <(F) Other Additives> The resin composition of the present invention may further contain (F) other additives as an optional component. The (F) other additives as component (F) do not include those corresponding to the above-mentioned components (A) to (E). Examples of (F) other additives include thermosetting resins other than epoxy resins (e.g., active ester resins, phenolic resins, naphthol resins, carbodiimide resins, acid anhydride resins, cyanate ester resins, and amine resins); sensitizers; adhesion aids; surfactants such as fluorine-based surfactants, nonionic surfactants, cationic surfactants, anionic surfactants, and silicone-based surfactants; thermoplastic resins; colorants such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium oxide, carbon black, and naphthalene black; hydroquinone, phenothiazine, methylhydroquinone, halogenated hydroxybenzoates, and the like. Examples of the (F) other additives include polymerization inhibitors such as hydroquinone monomethyl ether, catechol, and pyrogallol; thickeners such as bentone and montmorillonite; silicone-based, fluorine-based, and vinyl resin-based antifoaming agents; flame retardants such as phosphorus-based flame retardants (e.g., phosphate ester compounds, phosphazene compounds, phosphinic acid compounds, and red phosphorus), nitrogen-based flame retardants (e.g., melamine sulfate), halogen-based flame retardants, and inorganic flame retardants (e.g., antimony trioxide); ultraviolet absorbers such as benzotriazole-based ultraviolet absorbers; and stabilizers such as borate-based stabilizers, titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, and carboxylic anhydride-based stabilizers. One type of (F) other additive may be used alone, or two or more types may be used in combination.

[0127] <(G) Organic Solvent> The resin composition of the present invention may further contain an organic solvent (G) as an optional volatile component in combination with the non-volatile components such as the above-described components (A) to (F). Examples of the organic solvent include ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester-based solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, and γ-butyrolactone; ether-based solvents such as tetrahydropyran, tetrahydrofuran, 1,4-dioxane, diethyl ether, diisopropyl ether, dibutyl ether, diphenyl ether, and anisole; alcohol-based solvents such as methanol, ethanol, propanol, butanol, and ethylene glycol; 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl diglycol acetate, γ-butyrolactone, and methyl methoxypropionate. Examples of the organic solvent (G) include ether ester solvents such as ethyl acetate; ester alcohol solvents such as methyl lactate, ethyl lactate, and methyl 2-hydroxyisobutyrate; ether alcohol solvents such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether (butyl carbitol); amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; sulfoxide solvents such as dimethyl sulfoxide; nitrile solvents such as acetonitrile and propionitrile; aliphatic hydrocarbon solvents such as hexane, cyclopentane, cyclohexane, and methylcyclohexane; and aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene. The organic solvent (G) may be used singly or in combination of two or more.

[0128] The content of the (G) organic solvent in the resin composition may be, for example, 60% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 15% by mass or less, or 10% by mass or less, relative to 100% by mass of all components of the resin composition. The content of the (G) organic solvent in the resin composition may also be 0% by mass.

[0129] [Method for Producing Resin Composition] The resin composition can be produced, for example, by mixing components that can be contained in the resin composition. Thus, the resin composition can be produced by a production method including a step of mixing (A) an epoxy resin, (B) a photocurable resin, (C) a resin having a carboxyl group and an ethylenically unsaturated bond, and (D) a photopolymerization initiator. This production method may also include a step of mixing optional components such as components (E) to (G). Furthermore, if necessary, the components may be kneaded or stirred using a kneading device such as a three-roll mill, ball mill, bead mill, or sand mill, or a stirring device such as a super mixer or planetary mixer. Components (A) to (G) may be mixed in part or all at the same time, or they may be mixed sequentially.

[0130] [Characteristics of Resin Composition] The resin composition of the present invention contains a combination of components (A), (B), (C), and (D) (and, as necessary, components (E), (F), and (G)), and therefore can stably produce optical waveguides with low optical transmission loss.

[0131] The resin composition of the present invention can produce an optical waveguide having low optical transmission loss. For example, when the optical transmission loss of the optical waveguide is measured according to the method described in the section <Test Example 3: Measurement of Optical Transmission Loss> below, the average optical transmission loss is preferably less than 1 dB / cm, more preferably less than 0.5 dB / cm, and even more preferably less than 0.3 dB / cm.

[0132] The resin composition of the present invention makes it possible to stably obtain optical waveguides with low optical transmission loss. Therefore, when an optical waveguide is produced using the resin composition of the present invention, the standard deviation of the optical transmission loss can be reduced. Therefore, the resin composition of the present invention makes it possible to produce an optical waveguide with a low standard deviation of the optical transmission loss. For example, when the optical transmission loss of the optical waveguide is measured according to the method described in the section <Test Example 3: Measurement of Optical Transmission Loss> below, the standard deviation of the optical transmission loss is preferably less than 0.04 dB / cm, more preferably less than 0.02 dB / cm, and even more preferably less than 0.003 dB.

[0133] The resin composition of the present invention can produce an optical waveguide having a small standard deviation of optical transmission loss. Therefore, the resin composition of the present invention can produce an optical waveguide having a small coefficient of variation of optical transmission loss. For example, when the optical transmission loss of the optical waveguide is measured according to the method described in the section <Test Example 3: Measurement of Optical Transmission Loss> below, the value obtained by multiplying the coefficient of variation of optical transmission loss by 100 is preferably 7 or less, more preferably 5 or less, and even more preferably 4 or less.

[0134] [Uses of Resin Composition] The resin composition of the present invention can be used as a resin composition for producing an optical waveguide. Specifically, the resin composition of the present invention can be suitably used as a core resin composition for forming a core layer of an optical waveguide, and can also be suitably used as a clad resin composition for forming a clad layer of an optical waveguide. When producing an optical waveguide, the resin composition of the present invention may be used in the form of a resin composition set or a resin sheet set, which will be described later.

[0135] [Resin Sheet] The resin composition of the present invention can be used as it is, or may be used in the form of a resin sheet.

[0136] In one embodiment, the resin sheet includes a support and a layer of a resin composition (hereinafter simply referred to as a "resin composition layer") provided on the support, and is characterized in that the resin composition layer is formed from the resin composition of the present invention.

[0137] The thickness of the resin composition layer varies depending on the application, and may be appropriately determined depending on the application. For example, from the viewpoint of thinning, the thickness of the resin composition layer is preferably 100 μm or less, 80 μm or less, 60 μm or less, 50 μm or less, 40 μm or less, or 30 μm or less. The lower limit of the thickness of the resin composition layer is not particularly limited, but may be, for example, 1 μm or more, 5 μm or more, etc.

[0138] Examples of the support include a thermoplastic resin film, a metal foil, and a release paper, and a thermoplastic resin film and a metal foil are preferred. Therefore, in a preferred embodiment, the support is a thermoplastic resin film or a metal foil.

[0139] When a thermoplastic resin film is used as the support, examples of the thermoplastic resin include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), acrylics such as polycarbonate (PC) and polymethyl methacrylate (PMMA), cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, polyimide, etc. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred, and inexpensive polyethylene terephthalate is particularly preferred.

[0140] When a metal foil is used as the support, examples of the metal foil include copper foil and aluminum foil, with copper foil being preferred. The copper foil may be a foil made of a single metal, such as copper, or a foil made of an alloy of copper and another metal (e.g., tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.).

[0141] The surface of the support to be bonded to the resin composition layer may be subjected to a matte treatment, a corona treatment, or an antistatic treatment. Alternatively, the support may be a support with a release layer, which has a release layer on the surface to be bonded to the resin composition layer. Examples of the release agent used in the release layer of the support with a release layer include one or more release agents selected from the group consisting of alkyd resins, polyolefin resins, urethane resins, and silicone resins. Commercially available release agents include alkyd resin-based release agents such as "SK-1," "AL-5," and "AL-7" manufactured by Lintec Corporation. Commercially available release layer supports include PET films having a release layer primarily composed of an alkyd resin-based release agent, such as "SK-1," "AL-5," and "AL-7" manufactured by Lintec Corporation; "Lumirror T60" manufactured by Toray Industries, Inc.; "Purex" manufactured by Teijin Limited; and "Uni-Peel" manufactured by Unitika Ltd.

[0142] The thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, and more preferably in the range of 10 μm to 60 μm. When a support with a release layer is used, it is preferable that the thickness of the entire support with a release layer is in the above range.

[0143] When a metal foil is used as the support, a metal foil with a support substrate may be used, which is a thin metal foil with a peelable support substrate attached thereto. In one embodiment, the metal foil with a support substrate includes a support substrate, a release layer provided on the support substrate, and a metal foil provided on the release layer. When a metal foil with a support substrate is used as the support, the resin composition layer is provided on the metal foil.

[0144] In the metal foil with a supporting substrate, the material of the supporting substrate is not particularly limited, and examples thereof include copper foil, aluminum foil, stainless steel foil, titanium foil, copper alloy foil, etc. When copper foil is used as the supporting substrate, it may be electrolytic copper foil or rolled copper foil. Furthermore, the release layer is not particularly limited as long as it can release the metal foil from the supporting substrate, and examples thereof include an alloy layer of an element selected from the group consisting of Cr, Ni, Co, Fe, Mo, Ti, W, and P; an organic coating, etc.

[0145] In the metal foil with a supporting substrate, the material of the metal foil is preferably, for example, copper foil or copper alloy foil.

[0146] In the metal foil with a supporting substrate, the thickness of the supporting substrate is not particularly limited, but is preferably in the range of 10 μm to 150 μm, more preferably in the range of 10 μm to 100 μm. The thickness of the metal foil may be, for example, in the range of 0.1 μm to 10 μm.

[0147] In one embodiment, the resin sheet may further include an optional layer as needed. Examples of such optional layers include a protective film provided on the surface of the resin composition layer that is not bonded to the support (i.e., the surface opposite the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. By laminating the protective film, adhesion of dust and the like to the surface of the resin composition layer and scratches can be suppressed.

[0148] The resin sheet can be produced, for example, by preparing a resin varnish by dissolving the resin composition in an organic solvent or by applying the resin varnish to a support using a die coater or the like, and then drying the varnish to form a resin composition layer.

[0149] The organic solvent may be the same as the organic solvent described as a component of the resin composition. The organic solvent may be used alone or in combination of two or more.

[0150] Drying may be carried out by known methods such as heating or hot air blowing. Drying conditions are not particularly limited, but drying is carried out so that the content of organic solvent in the resin composition layer becomes 10% by mass or less, preferably 5% by mass or less. Although this varies depending on the boiling point of the organic solvent in the resin composition or resin varnish, for example, when a resin composition or resin varnish containing 30% by mass to 60% by mass of organic solvent is used, the resin composition layer can be formed by drying at 50°C to 150°C for 3 to 10 minutes.

[0151] The resin composition may be applied in several batches, in one batch, or by a combination of different methods. Among these, the die coating method is preferred because it provides excellent uniformity. Furthermore, to avoid contamination, it is preferable to carry out the application process in an environment where foreign matter is less likely to be generated, such as a clean room.

[0152] The resin sheet can be stored in a rolled state. There may be cases where the resin sheet is not used immediately after production. In such cases, it is preferable to store the resin sheet in a frozen and / or refrigerated state after production so as not to impair its properties. Among these, it is more preferable to store the resin sheet in a frozen state after production. The temperature conditions for storing the resin sheet in a frozen or refrigerated state are, for example, 8°C or lower, preferably 0°C or lower, and more preferably -18°C or lower. The lower limit of such a temperature is not particularly limited and can be, for example, -40°C or higher. When the resin sheet is stored in a frozen or refrigerated state, it is desirable to thaw and adjust the temperature by leaving the resin sheet in a usage environment (temperature 15°C to 28°C, relative humidity 40% RH to 60% RH), and use the resin sheet after the resin composition layer contained in the resin sheet has reached the same temperature as the usage environment, but this is not limited thereto. When the resin sheet has a protective film, it can be used by peeling off the protective film.

[0153] [Resin Composition Set] A resin composition set according to one embodiment of the present invention includes a core resin composition and a clad resin composition. The core resin composition includes the resin composition of the present invention, and preferably includes only the resin composition of the present invention. The clad resin composition includes the resin composition of the present invention, and preferably includes only the resin composition of the present invention. The core resin composition can be suitably used as a resin composition for forming a core layer of an optical waveguide, and the clad resin composition can be suitably used as a resin composition for forming a clad layer of an optical waveguide. The resin composition set can be used in the production of an optical waveguide comprising a core layer containing a cured product of the core resin composition and a clad layer containing a cured product of the clad resin composition.

[0154] As described above, the resin composition set can be used as a resin composition for producing an optical waveguide. The resin composition set is preferably used to form an optical waveguide capable of transmitting light with a wavelength of 1300 nm to 1320 nm, and is also preferably used to form a single-mode optical waveguide. In a more preferred embodiment, the resin composition set can be used to form a single-mode optical waveguide for light with a wavelength of 1310 nm.

[0155] [Resin Sheet Set] A resin sheet set according to one embodiment of the present invention includes a core resin sheet and a clad resin sheet. The core resin sheet includes a support and a resin composition layer provided on the support, the resin composition layer including a core resin composition. The clad resin sheet includes a support and a resin composition layer provided on the support, the resin composition layer including a clad resin composition. The core resin composition and clad resin composition included in the resin sheet set are as described above. The resin sheet set can achieve the same advantages as the resin composition set described above, and furthermore, since an optical waveguide can be produced by laminating the respective resin sheets, the production of an optical waveguide can be performed more easily.

[0156] As the support contained in the core resin sheet and the clad resin sheet, for example, the support described above in the section [Resin Sheet] can be used.

[0157] In the resin sheet set, the resin composition layer may be protected by a protective film regardless of whether it is a core resin sheet or a clad resin sheet. As the protective film that may be included in the resin sheet set, for example, the protective film described above in the section [Resin Sheet] can be used.

[0158] For the manufacturing methods of the core resin sheet and the clad resin sheet, reference can be made to the manufacturing methods described above in the section [Resin Sheet]. For example, in the manufacturing of the core resin sheet, the core resin sheet can be manufactured by using the core resin composition as the resin composition. Also, for example, in the manufacturing of the clad resin sheet, the clad resin sheet can be manufactured by using the clad resin composition as the resin composition.

[0159] As described above, the resin sheet set can be used as a resin composition for producing an optical waveguide. The resin sheet set is preferably used to form an optical waveguide capable of transmitting light with a wavelength of 1300 nm to 1320 nm, and is also preferably used to form a single-mode optical waveguide. In a more preferred embodiment, the resin sheet set can be used to form a single-mode optical waveguide for light with a wavelength of 1310 nm.

[0160] [Optical Waveguide and Manufacturing Method Thereof] An optical waveguide can be manufactured using the resin composition set and resin sheet set described above. The present invention also provides such an optical waveguide. Hereinafter, embodiments of the optical waveguide will be described with reference to the drawings.

[0161] Fig. 1 is a perspective view schematically showing an optical waveguide 10 according to one embodiment of the present invention. As shown in Fig. 1, the optical waveguide 10 includes a core layer 100 and a clad layer 200. The core layer 100 and the clad layer 200 contain a cured product of the resin composition of the present invention, and preferably contain only a cured product of the resin composition of the present invention.

[0162] The core layer 100 is provided in the cladding layer 200. Thus, the core layer 100 is covered by the cladding layer 200. In one example, the entire peripheral surface of the core layer 100 is covered by the cladding layer 200. The core layer 100 and the cladding layer 200 are in direct contact with each other without any other layer therebetween, and therefore an interface 100I can be formed between the core layer 100 and the cladding layer 200. Because the core layer 100 has a higher refractive index than the cladding layer 200, light (not shown) can be transmitted within the core layer 100 from one end (incident end) 100A of the core layer 100 to the other end (exit end) 100B.

[0163] Various wavelengths of light can be selected that can be transmitted by the optical waveguide 10. For example, preferred wavelength ranges of the transmitted light can be 840 nm to 860 nm (e.g., 850 nm), 1300 nm to 1320 nm (e.g., 1310 nm), 1540 nm to 1560 nm (e.g., 1550 nm), etc. Among these, the wavelength range of light transmitted through the optical transmission line 10 is preferably 1300 nm to 1320 nm.

[0164] The optical waveguide 10 may be a single-mode optical waveguide or a multi-mode optical waveguide, but is preferably a single-mode optical waveguide. In particular, the optical waveguide 10 is preferably a single-mode optical waveguide for light in the preferred wavelength range described above. For example, the optical waveguide 10 is preferably a single-mode optical waveguide for light with a wavelength of 1310 nm.

[0165] It is desirable to set the width L of the core layer 100 appropriately within a range that allows light transmission. A specific range of the width L of the core layer 100 is preferably 0.5 μm or more, more preferably 1 μm or more, and even more preferably 2 μm or more, and is preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less or 5 μm or less. The width L of the core layer 100 corresponds to the line width (line) of the core layer 100 when viewed in the thickness direction.

[0166] It is desirable to set the spacing S of the core layers 100 appropriately within a range that allows light transmission. A specific range of the spacing S of the core layers 100 is preferably 50 μm or more, more preferably 70 μm or more, and even more preferably 100 μm or more, and is preferably 1000 μm or less, more preferably 700 μm or less, and even more preferably 500 μm or less. The spacing S of the core layers 100 corresponds to the spacing (space) between the core layers as viewed in the thickness direction.

[0167] It is desirable to set the thickness T of the core layer 100 appropriately within a range that allows light transmission. A specific range of the thickness T of the core layer 100 is preferably 0.5 μm or more, more preferably 1 μm or more, and even more preferably 2 μm or more, and is preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less or 10 μm or less.

[0168] The thickness of the cladding layer 200 is greater than the thickness T of the core layer 100. The specific thickness of the cladding layer 200 is preferably 5 μm or more, more preferably 7 μm or more, and even more preferably 10 μm or more, and is preferably 100 μm or less, more preferably 60 μm or less, and even more preferably 40 μm or less or 30 μm or less.

[0169] The optical waveguide 10 may include any element other than the core layer 100 and the cladding layer 200, as needed. Examples of the optional elements include a protective layer (not shown) that protects the core layer 100 and the cladding layer 200, a wiring layer (not shown) such as a plating layer, a trench or hole (not shown) for forming the wiring layer, and a substrate 300. In the optical waveguide 10 that includes the substrate 300, the cladding layer 200 is usually provided on the substrate 300, and the core layer 100 is provided within the cladding layer 200.

[0170] The substrate 300 may be a hard substrate such as a glass substrate, metal substrate, ceramic substrate, wafer, or circuit board. Examples of the wafer include semiconductor wafers such as silicon wafers, gallium arsenide (GaAs) wafers, indium phosphide (InP) wafers, gallium phosphide (GaP) wafers, gallium nitride (GaN) wafers, gallium telluride (GaTe) wafers, zinc selenium (ZnSe) wafers, and silicon carbide (SiC) wafers, or pseudo wafers. Examples of the pseudo wafer include a plate-shaped member comprising a molding resin and electronic components embedded in the molding resin. Examples of the circuit board include a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, and a thermosetting polyphenylene ether substrate. Here, the term "circuit board" refers to a substrate having a patterned conductor layer (circuit) formed on one or both sides of the above-mentioned substrate. Furthermore, the substrate 300 may be a film formed of a plastic material such as polyethylene terephthalate, polyimide, polyester, etc. Furthermore, a flexible circuit board may be employed as the substrate 300.

[0171] The optical waveguide 10 can be manufactured using the resin composition set and / or resin sheet set described above. For example, the optical waveguide 10 can be manufactured by a method including, in this order: (1) a step of forming a first resin composition layer containing a cladding resin composition; (2) a step of curing the first resin composition layer; (3) a step of forming a second resin composition layer containing a core resin composition on the first resin composition layer; (4) a step of exposing the second resin composition layer; (5) a step of developing the second resin composition layer; (6) a step of curing the second resin composition layer; (7) a step of forming a third resin composition layer containing a cladding resin composition on the second resin composition layer; and (8) a step of curing the third resin composition layer. As described above, the resin composition set and / or resin sheet set include the resin compositions of the present invention as the core resin composition and the cladding resin composition. Therefore, the resin composition of the present invention is also used as the core resin composition and the clad resin composition in the method for producing the optical waveguide 10. The method for producing the optical waveguide 10 may, if necessary, include a step (9) of forming a conductor layer as a wiring layer after the step (8) is completed.

[0172] <Step (1)> A method for producing an optical waveguide according to one embodiment of the present invention includes a step (1) of forming a first resin composition layer containing a cladding resin composition.

[0173] 2 is a schematic cross-sectional view illustrating step (1) of a method for producing an optical waveguide according to an embodiment of the present invention. In this embodiment, as shown in FIG. 2, an example in which a first resin composition layer 210 is formed on a substrate 300 is described.

[0174] There are no particular limitations on the method for forming the first resin composition layer 210. For example, the first resin composition layer 210 may be formed by applying a cladding resin composition onto the substrate 300. From the viewpoint of smooth application, a varnish-like cladding resin composition containing a solvent may be prepared, and the varnish-like cladding resin composition may be applied.

[0175] Examples of coating methods include gravure coating, microgravure coating, reverse coating, kiss reverse coating, die coating, slot die coating, lip coating, comma coating, blade coating, roll coating, knife coating, curtain coating, chamber gravure coating, slot orifice coating, spin coating, slit coating, spray coating, dip coating, hot melt coating, bar coating, applicator coating, air knife coating, curtain flow coating, offset printing, brush coating, and screen printing.

[0176] The cladding resin composition may be applied in one application or in multiple applications. Alternatively, different application methods may be combined. To avoid contamination, application is preferably performed in an environment where foreign matter is unlikely to be generated, such as a clean room.

[0177] After application of the cladding resin composition, the first resin composition layer 210 may be dried, if necessary. Drying can be performed using a drying device such as a hot air oven or a far-infrared oven. Drying conditions are preferably set appropriately depending on the composition of the cladding resin composition. Specific examples include a drying temperature of preferably 50°C or higher, more preferably 70°C or higher, and even more preferably 80°C or higher, and preferably 150°C or lower, more preferably 130°C or lower, and even more preferably 120°C or lower. Furthermore, the drying time is preferably 30 seconds or higher, more preferably 60 seconds or higher, and even more preferably 120 seconds or higher, and preferably 60 minutes or shorter, more preferably 20 minutes or shorter, and even more preferably 5 minutes or shorter.

[0178] The first resin composition layer 210 may be formed using, for example, a clad resin sheet. Specifically, the first resin composition layer 210 can be formed on the substrate 300 by laminating the resin composition layer of the clad resin sheet on the substrate 300. The lamination is performed, for example, by pressing the resin composition layer of the clad resin sheet onto the substrate 300 while heating it. This lamination is preferably performed under reduced pressure by a vacuum lamination method. Furthermore, prior to lamination, a preheat treatment may be performed to heat the resin sheet and the substrate, as necessary.

[0179] The lamination conditions are, for example, a pressure bonding temperature (lamination temperature) of 70°C to 140°C and a pressure bonding pressure of 1 kgf / cm. ２ ~11 kgf / cm ２ (9.8 x 10 ４ N / m ２ ~107.9 x 10 ４ N / m ２ The lamination can be carried out under the conditions of a pressure of 20 mmHg (26.7 hPa) or less, and a pressure bonding time of 5 to 300 seconds. The lamination is preferably carried out under reduced pressure with an air pressure of 20 mmHg (26.7 hPa) or less. The lamination may be carried out in a batch system or continuously using a roll.

[0180] The vacuum lamination method can be carried out using a commercially available vacuum laminator, such as a vacuum applicator manufactured by Nikko Materials Co., Ltd., a vacuum pressure laminator manufactured by Meiki Seisakusho Co., Ltd., a roll dry coater manufactured by Hitachi Industries, Ltd., or a vacuum laminator manufactured by Hitachi AIC Corporation.

[0181] When the first resin composition layer 210 is formed using a clad resin sheet having a support, the support is usually peeled off at an appropriate time before the step (3).

[0182] The first resin composition layer 210 formed on the substrate 300 in step (1) contains a cladding resin composition, and preferably contains only a cladding resin composition.

[0183] <Step (2)> The method for producing an optical waveguide according to one embodiment of the present invention includes, after step (1), step (2) of curing the first resin composition layer. This step (2) may involve, for example, heat treating the first resin composition layer 210. The conditions for the heat treatment may be selected depending on the composition of the resin composition, and may be preferably in the range of 150°C to 250°C for 20 minutes to 180 minutes, and more preferably in the range of 160°C to 230°C for 30 minutes to 120 minutes. The heat treatment may be performed in air or in an inert gas atmosphere such as nitrogen. In particular, the heat treatment is preferably performed in an inert gas atmosphere such as nitrogen.

[0184] The first resin composition layer 210 may be cured by an exposure treatment. As the light used in the exposure treatment, it is preferable to use an appropriate actinic ray according to the composition of the resin composition of the present invention. The wavelength of the actinic ray is, for example, 190 nm to 1000 nm, preferably 240 nm to 550 nm, but light rays of other wavelengths may also be used. Specific examples of actinic light sources include ultraviolet light, visible light, electron beams, X-rays, etc., with ultraviolet light being preferred. The exposure dose range is preferably 10 mJ / cm. ２ More preferably, 50 mJ / cm ２ More preferably, 200 mJ / cm ２ or more, preferably 10,000 mJ / cm ２ or less, more preferably 8,000 mJ / cm ２ More preferably, 4,000 mJ / cm or less ２ Below, 3,000mJ / cm ２ Below, 2,000mJ / cm ２ or less or 1,000 mJ / cm ２ The first resin composition layer 210 may be cured by a combination of exposure treatment and heat treatment.

[0185] When the first resin composition layer 210 is formed using a clad resin sheet having a support, in step (2), a support (not shown) may be present on the first resin composition layer 210. When a support is present on the first resin composition layer 210, exposure may be performed through the support, or exposure may be performed after peeling off the support.

[0186] 3 is a schematic cross-sectional view illustrating step (2) of the method for manufacturing an optical waveguide according to one embodiment of the present invention. By curing the first resin composition layer 210 in step (2), a cured first resin composition layer 220 is obtained on the substrate 300, as shown in FIG. 3. This cured first resin composition layer 220 forms a part of the cladding layer 200, and may be referred to as the "first cladding layer" 220 hereinafter.

[0187] <Step (3)> The method for producing an optical waveguide according to one embodiment of the present invention includes, after step (2), step (3) of forming a second resin composition layer containing a core resin composition on the first resin composition layer.

[0188] 4 is a schematic cross-sectional view illustrating step (3) of the method for producing an optical waveguide according to one embodiment of the present invention. In step (3), as shown in FIG. 4, a second resin composition layer 110 containing a core resin composition is formed on a first clad layer 220 as a cured first resin composition layer.

[0189] There are no particular limitations on the method for forming the second resin composition layer 110. For example, the second resin composition layer 110 may be formed by applying a core resin composition onto the first clad layer 220. From the viewpoint of smooth application, a varnish-like core resin composition may be applied. The application of the core resin composition in step (3) may be performed in the same manner as the application of the clad resin composition in step (1). Furthermore, after application of the core resin composition, the second resin composition layer 110 may be dried, if necessary. The second resin composition layer 110 may be dried using the same method and conditions as those for drying the first resin composition layer 210.

[0190] The second resin composition layer 110 may be formed, for example, using the core resin sheet described above. Specifically, the second resin composition layer 110 can be formed on the first clad layer 220 by laminating the resin composition layer of the core resin sheet on the first clad layer 211. The lamination of the core resin sheet in step (3) can be performed in the same manner as the lamination of the clad resin sheet in step (1). The support of the core resin sheet is peeled off at an appropriate time before step (5).

[0191] The second resin composition layer 110 formed on the first clad layer 220 in step (3) contains a core resin composition, and preferably contains only a core resin composition.

[0192] <Step (4)> The method for producing an optical waveguide according to one embodiment of the present invention includes, after step (3), step (4) of subjecting the second resin composition layer to an exposure treatment.

[0193] 5 is a schematic cross-sectional view illustrating step (4) of the method for manufacturing an optical waveguide according to one embodiment of the present invention. In step (4), as shown in FIG. 5 , a latent image is formed in the second resin composition layer 110 by selective exposure treatment. Specifically, in the exposure treatment, light P is selectively irradiated onto specific portions of the second resin composition layer 110. Thus, after the exposure treatment, the second resin composition layer 110 is provided with an exposed portion 111 that has been irradiated with light and an unexposed portion 112 that has not been irradiated with light. Typically, the core resin composition functions as a negative-tone photosensitive resin composition, so that the exposed portion 111 forms a latent image corresponding to the core layer.

[0194] From the viewpoint of performing selective exposure, the exposure treatment in step (4) is usually performed using a mask 400. Specifically, in this exposure treatment, light P is irradiated onto the second resin composition layer 110 through a mask 400 having a light-transmitting portion 410 and a light-shielding portion 420. The light P passes through the light-transmitting portion 410 and enters the exposed portion 111, but cannot pass through the light-shielding portion 420 and therefore cannot enter the non-exposed portion 112. Therefore, the exposed portion 111 and the non-exposed portion 112 corresponding to the light-transmitting portion 410 and the light-shielding portion 420 can be provided in the second resin composition layer 110. The mask 400 may be brought into close contact with the second resin composition layer 110 (contact exposure method) as shown in FIG. 5, or exposure may be performed using parallel light without contact (non-contact exposure method).

[0195] Generally, the light-transmitting portion 410 of the mask 400 is formed to have a planar shape corresponding to the core layer of the optical waveguide. Therefore, the light-shielding portion 420 of the mask 400 is formed to have a planar shape corresponding to the portion of the optical waveguide where the core layer is not present. Unless otherwise specified, the "planar shape" refers to the shape as viewed from the thickness direction. The light-transmitting portion 410 formed in a planar shape corresponding to the core layer may be referred to as a "mask pattern" hereinafter.

[0196] The light P used in the exposure treatment in step (IV) can be actinic rays in the same range as that used in the exposure treatment of the first resin composition layer 210 in step (2). The exposure dose of the light P is preferably set so that a desired core layer can be formed after curing in step (7). In one example, the specific range of exposure dose in step (4) can be the same range as that of the exposure dose to the first resin composition layer 210 in step (2).

[0197] When the second resin composition layer 110 is formed using a core resin sheet having a support, in step (4), a support (not shown) may be present on the second resin composition layer 110. When a support is present on the second resin composition layer 110, exposure may be performed through the support, or exposure may be performed after peeling off the support.

[0198] Because the core resin composition functions as a negative photosensitive resin composition, the solubility in a developer is reduced in the exposed portion 111. On the other hand, the solubility in a developer is high in the non-exposed portion 112. Utilizing this difference in solubility between the exposed portion 111 and the non-exposed portion 112, the subsequent development process in step (5) is carried out.

[0199] The method for producing an optical waveguide according to one embodiment of the present invention may include a step (X) of preheating the second resin composition layer 110 after the step (4) and before the step (5) in order to cure the second resin composition layer 110. The step (X) can quickly reduce the solubility of the exposed portion 111 in a developer. The heating in the step (X) may be performed using a hot plate or an oven. The heating temperature may be, for example, 40°C or higher and 110°C or lower. The heating time may be, for example, 30 seconds or higher and 60 minutes or lower.

[0200] <Step (5)> The method for producing an optical waveguide according to one embodiment of the present invention includes, after step (4), step (5) of subjecting the third resin composition layer to a development treatment.

[0201] 6 is a schematic cross-sectional view illustrating step (5) of the method for producing an optical waveguide according to one embodiment of the present invention. The development process in step (5) allows the latent image formed in step (4) to be developed. Because the core resin composition functions as a negative-tone photosensitive resin composition, the development process does not remove the exposed portion 111, but removes the non-exposed portion 112 (see FIG. 5), as shown in FIG. 6. The exposed portion 111 of the second resin composition layer remaining after development can have the same planar shape as the mask pattern of the light-transmitting portion 410 (see FIG. 5) of the mask 400 used in step (4).

[0202] The developing method is usually a wet developing method in which the second resin composition layer 110 is brought into contact with a developer, and an alkaline aqueous solution is usually used as the developer.

[0203] Examples of alkaline aqueous solutions used as developers include aqueous solutions of alkali metal compounds. Examples of alkali metal compounds include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; alkali metal carbonates or bicarbonates such as sodium carbonate and sodium bicarbonate; alkali metal phosphates such as sodium phosphate and potassium phosphate; and alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate. Examples of alkaline aqueous solutions include aqueous solutions of organic bases that do not contain metal ions, such as tetramethylammonium hydroxide. One type of alkaline aqueous solution may be used alone, or two or more types may be used in combination. Among these, aqueous solutions of organic bases that do not contain metal ions are preferred from the viewpoint of significantly achieving the effects of the present invention.

[0204] The developer may contain additives such as surfactants and antifoaming agents, if necessary, to improve the developing action.

[0205] The development time is preferably 10 seconds to 5 minutes. The temperature of the developer during development is not particularly limited, but is preferably 20° C. or higher and 50° C. or lower, more preferably 40° C. or lower.

[0206] Examples of development methods include puddle, spray, immersion, brushing, slapping, and ultrasonic methods. Among these, the spray method is suitable for improving resolution. When using the spray method, the spray pressure is preferably 0.05 MPa to 0.3 MPa.

[0207] After development using the developer, the second resin composition layer 110 may be further rinsed. The rinse is preferably performed with a solvent different from the developer. The rinsing time is preferably 5 seconds to 1 minute.

[0208] After development using a developer, a desmear treatment may be performed to remove the non-exposed portion 112 that cannot be completely removed by development. The desmear treatment may be performed according to various methods used in the manufacture of printed wiring boards and known to those skilled in the art.

[0209] <Step (6)> The method for producing an optical waveguide according to one embodiment of the present invention includes, after step (5), step (6) of curing the second resin composition layer.

[0210] 7 is a schematic cross-sectional view illustrating step (6) of the method for producing an optical waveguide according to one embodiment of the present invention. By curing the second resin composition layer 110 in step (6), a core layer 100 is obtained as a cured second resin composition layer on the first cladding layer 220, as shown in FIG.

[0211] <Step (7)> ​​The method for producing an optical waveguide according to one embodiment of the present invention includes, after step (6), step (7) of forming a third resin composition layer containing a cladding resin composition on the second resin composition layer.

[0212] 8 is a schematic cross-sectional view illustrating step (7) of the method for manufacturing an optical waveguide according to one embodiment of the present invention. In step (7), as shown in FIG. 8 , a third resin composition layer 230 containing a cladding resin composition is formed on the core layer 100. The third resin composition layer 230 is usually formed so as to cover the entire peripheral surface of the core layer 100 that is not in contact with the first cladding layer 220. Therefore, the third resin composition layer 230 is formed so as to cover the core layer 100, and is also formed on the first cladding layer 220.

[0213] There are no particular limitations on the method for forming the third resin composition layer 230. For example, the third resin composition layer 230 may be formed by applying a cladding photosensitive resin composition onto the core layer 100 (and further onto the first cladding layer 220, if necessary). The application of the cladding resin composition to form the third resin composition layer 230 may be carried out in the same manner as the application of the cladding resin composition to form the first resin composition layer 210. Furthermore, after application of the cladding resin composition, the third resin composition layer 230 may be dried, if necessary. The third resin composition layer 230 may be dried using the same method and conditions as those used to dry the first composition layer 210.

[0214] The third resin composition layer 230 may be formed using, for example, a clad resin sheet. Specifically, the third resin composition layer 230 can be formed on the core layer 100 by laminating a resin composition layer of a clad resin sheet on the core layer 100 (and, if necessary, the first clad layer 220). The lamination of the clad resin sheet to form the third resin composition layer 230 can be performed in the same manner as the lamination of the clad resin sheet to form the first resin composition layer 210. When the third resin composition layer 230 is formed using a clad resin sheet provided with a support, the support may be peeled off in any step.

[0215] The third composition layer 230 formed on the core layer 100 in step (7) contains a cladding photosensitive resin composition, and preferably contains only a cladding photosensitive resin composition.

[0216] <Step (8)> The method for producing an optical waveguide according to one embodiment of the present invention includes step (8) of curing the third resin composition layer after step (7). The curing of the third resin composition layer 230 in step (8) can usually be carried out in the same manner as the curing of the first resin composition layer 210 in step (2).

[0217] 9 is a schematic cross-sectional view illustrating step (8) of the method for manufacturing an optical waveguide according to one embodiment of the present invention. By curing the third resin composition layer 230 in step (8), a cured third resin composition layer 240 is obtained on the core layer 100, as shown in FIG. 9 . This cured third resin composition layer 240 forms a part of the cladding layer 200 and may be referred to as the "second cladding layer" 240 hereinafter. The cladding layer 200 is then formed from this second cladding layer 240 and the first cladding layer 220. Thus, an optical waveguide 10 can be obtained, which includes the cladding layer 200 including the first cladding layer 220 and the second cladding layer 240, and the core layer 100 provided within this cladding layer 200.

[0218] <Step (9)> The method for manufacturing an optical waveguide according to one embodiment of the present invention may further include, after step (8), step (9) of forming a conductor layer as a wiring layer. The conductor layer may be formed in any location; for example, the conductor layer may be formed inside a trench or a hole, or may be formed on the second cladding layer 240, for example. The conductor layer is preferably formed by plating. Furthermore, before forming the conductor layer by plating, the location where the conductor layer is to be formed may be subjected to a roughening treatment.

[0219] 10 is a schematic cross-sectional view illustrating step (9) of the method for producing an optical waveguide according to one embodiment of the present invention. In this embodiment, as shown in FIG. 10, an example of forming a conductor layer on a second cladding layer 240 will be described. Because the second cladding layer 240 contains the resin composition of the present invention, it is possible to improve the peel strength between the second cladding layer 240 and the conductor layer 500 even if the arithmetic mean roughness (Ra) after the roughening treatment is small.

[0220] The procedure and conditions for the roughening treatment are not particularly limited. For example, the second cladding layer 240 can be roughened by performing a swelling treatment with a swelling liquid, a roughening treatment with an oxidizing agent, and a neutralization treatment with a neutralizing liquid in this order.

[0221] Examples of swelling liquids used in the roughening treatment include alkaline solutions and surfactant solutions, with alkaline solutions being preferred. Examples of alkaline solutions include sodium hydroxide solutions and potassium hydroxide solutions. Examples of commercially available swelling liquids include "Swelling Dip Securigans P" and "Swelling Dip Securigans SBU" manufactured by Atotech Japan. The swelling treatment using a swelling liquid is not particularly limited, but can be performed, for example, by immersing the area where the conductor layer is to be formed in a swelling liquid at 30°C to 90°C for 1 to 20 minutes. From the viewpoint of suppressing swelling of the resin of the second clad layer 240 to an appropriate level, it is preferable to immerse the area where the conductor layer is to be formed in a swelling liquid at 40°C to 80°C for 5 to 15 minutes.

[0222] An example of an oxidizing agent used in the roughening treatment is an alkaline permanganate solution prepared by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. The roughening treatment using an oxidizing agent such as an alkaline permanganate solution is preferably carried out by immersing the second clad layer 240 in an oxidizing agent solution heated to 60°C to 100°C for 10 to 30 minutes. The concentration of permanganate in the alkaline permanganate solution is preferably 5% by mass to 10% by mass. Commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact CP" and "Dosing Solution Securigance P" manufactured by Atotech Japan.

[0223] The neutralizing solution used in the roughening treatment is preferably an acidic aqueous solution, and a commercially available product such as "Reduction Solution Securigant P" manufactured by Atotech Japan, Inc. Treatment with a neutralizing solution can be carried out by immersing the surface that has been roughened with an oxidizing agent in a neutralizing solution at 30°C to 80°C for 5 to 30 minutes. From the standpoint of workability, etc., a method in which the object that has been roughened with an oxidizing agent is immersed in a neutralizing solution at 40°C to 70°C for 5 to 20 minutes is preferred.

[0224] The arithmetic mean roughness Ra of the surface of the second cladding layer 240 after the roughening treatment is preferably 500 nm or less, more preferably less than 400 nm, even more preferably 200 nm or less, and more preferably less than 200 nm. The lower limit is not particularly limited, and may be, for example, 1 nm or more, 2 nm or more, etc.

[0225] After the roughening treatment is completed, the conductor layer 500 is formed on the roughened second cladding layer 240. Specifically, the semi-additive method is preferable from the viewpoint of ease of manufacturing, since the surface of the roughened area can be plated by a method such as a semi-additive method or a full-additive method to form a conductor layer having a desired shape. An example of forming a conductor layer by a semi-additive method is shown below.

[0226] A plating seed layer is formed by electroless plating on the roughened area. A second mask pattern is then formed on the formed plating seed layer, exposing a portion of the plating seed layer in accordance with the desired shape. A metal layer is then formed on the exposed plating seed layer by electrolytic plating, and the second mask pattern is then removed. The unnecessary plating seed layer is then removed by etching or the like, forming a conductor layer having a desired wiring pattern.

[0227] The method for manufacturing the optical waveguide 10 may further include any optional steps in combination with the steps described above. The method for manufacturing the optical waveguide 10 may further include, for example, a step of forming a protective layer (not shown). The method for manufacturing the optical waveguide 10 may further include, for example, a step of forming a trench or a hole (not shown). The method for manufacturing the optical waveguide 10 may further include, for example, a step of dicing the manufactured optical waveguide 10.

[0228] The above-described steps may be repeated in the method for manufacturing the optical waveguide 10. For example, steps (1) to (8) (including step (9) as necessary) may be repeated to manufacture an optical waveguide having a multilayer structure in which core layers and clad layers are alternately arranged in the thickness direction on the substrate 300.

[0229] [Opto-electrical Hybrid Board and Manufacturing Method Thereof] An opto-electrical hybrid board according to one embodiment of the present invention includes the optical waveguide described above. Typically, the opto-electrical hybrid board includes an optical waveguide and an electric circuit board. The electric circuit board may include electronic components and wiring connected to the electronic components. Examples of the electronic components include passive components such as capacitors, inductors, and resistors; and active components such as semiconductor chips. The optical waveguide and the wiring of the electric circuit board may be connected via an opto-electrical conversion element. The opto-electrical conversion element may include a combination of a light-emitting element (e.g., a surface-emitting light-emitting diode) capable of converting electricity to light and a light-receiving element (e.g., a photodiode) capable of converting light to electricity. Furthermore, the opto-electrical hybrid board may include an optical element such as a mirror for adjusting the optical path.

[0230] A preferred example of an opto-electrical hybrid substrate is one that includes a chip in which an optical integrated circuit is formed on a silicon wafer. This chip is expected to be put to practical use in the near future using silicon photonics, and is expected to be mounted, for example, in a semiconductor package. An opto-electrical hybrid substrate that includes this chip includes, for example, an electric circuit board, a chip mounted on the electric circuit board, and an optical waveguide. The optical waveguide can be used to connect the wiring of the electric circuit board to the chip or to connect multiple chips together.

[0231] Chips manufactured using silicon photonics generally use light with wavelengths of 1310 nm and 1550 nm, with 1310 nm being the most common (Sho Yoshida, Daisuke Suganuma, Takaaki Ishigure, "Fabrication of Single-Mode Polymer Waveguides Using the Mosquito Method and Low Loss," 28th Spring Conference of the Japan Institute of Electronics Packaging, 2014). Therefore, it is preferable that the optical waveguide be capable of transmitting light with wavelengths of 1310 nm and 1550 nm or close thereto, and it is preferable that it be capable of transmitting light with wavelengths of, for example, 1300 nm to 1320 nm. The optical waveguides according to the above-described embodiments are capable of transmitting light with these wavelengths.

[0232] Generally, between single mode and multimode, single mode can achieve faster transmission. Therefore, from the viewpoint of high-speed transmission, single mode optical waveguides are preferable as optical waveguides applied to optical-electrical hybrid circuits. In single mode optical waveguides, it is preferable that the width of the core layer is small. For example, it is preferable to form a core layer with a width of 10 μm or less, or 5 μm or less. Furthermore, optical waveguides having such a narrow core layer are preferable from the viewpoint of increasing the degree of freedom in package design when the optical waveguide is applied to a semiconductor package. According to the optical waveguides of the above-described embodiments, it is possible to reduce the width of the core layer as described above.

[0233] On the other hand, when connecting multiple opto-electrical hybrid boards, the boards may be connected via optical fibers. For example, multiple opto-electrical hybrid boards may be installed in a rack and connected to each other via optical fibers. Multimode optical fibers are the mainstream for connecting boards in this way. Therefore, from the perspective of enabling connection with optical fibers, a multimode optical waveguide may be used as the optical waveguide provided in the opto-electrical hybrid board.

[0234] From the viewpoint of enhancing versatility, it is desirable that the optical waveguide be applicable to both single-mode and multi-mode. Furthermore, it is desirable to reduce the minimum width of the core layer of such optical waveguides to increase the degree of freedom in the line width of the core layer. According to the optical waveguides of the above-described embodiments, by using the core resin composition of the present invention for the core, a fine core can be formed, thereby reducing the minimum width of the core layer. Furthermore, according to the optical waveguides of the above-described embodiments, both single-mode and multi-mode optical waveguides can be obtained. Therefore, the optical waveguides of the above-described embodiments can be applied in a wide range of applications. Furthermore, because the optical waveguides of the above-described embodiments are applicable in such a wide range of applications and can suppress optical transmission loss, they are suitable for application to opto-electrical hybrid boards.

[0235] Since the opto-electric hybrid board includes the optical waveguide described above, the manufacturing method of the opto-electric hybrid board includes the same method as the manufacturing method of the optical waveguide.

[0236] [Semiconductor Device] A semiconductor device according to one embodiment of the present invention includes the above-described opto-electric hybrid substrate. Examples of such semiconductor devices include various semiconductor devices used in electrical products (e.g., computers, mobile phones, smartphones, tablet devices, wearable devices, digital cameras, medical equipment, and televisions) and vehicles (e.g., motorcycles, automobiles, trains, ships, and aircraft).

[0237] The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these examples. In the following description, "parts" and "%" representing amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified. Furthermore, the temperature and pressure conditions were room temperature (23°C) and atmospheric pressure (1 atm), unless otherwise specified.

[0238] Synthesis Example 1: Synthesis of Acid-Modified Epoxy Acrylate Resin C 325 parts of an epoxy resin having a naphthol aralkyl skeleton and an epoxy equivalent of 330 g / eq. ("ESN-475V," manufactured by Nippon Steel Chemical & Material Co., Ltd.) were placed in a flask equipped with a gas inlet tube, a stirrer, a condenser, and a thermometer, 340 parts of propylene glycol monomethyl ether were added, and the mixture was heated and dissolved. 0.46 parts of hydroquinone and 1 part of triphenylphosphine were then added. This mixture was heated to 95-105°C, and 72 parts of acrylic acid were slowly added dropwise, allowing the mixture to react for 16 hours. The reaction product was cooled to 80-90°C, and 130 parts of tetrahydrophthalic anhydride were added. The mixture was allowed to react for 8 hours and then cooled. The solvent was removed, yielding an acid-modified epoxy acrylate resin C having an acid value of 90 mgKOH / g of solid matter and a non-volatile content of 70% by mass. The weight average molecular weight (Mw) of the obtained acid-modified epoxy acrylate resin C was 1,000.

[0239] <Production Examples 1 to 29: Preparation of Resin Compositions> Each component was weighed and mixed in the amount (parts by mass of non-volatile components) shown in Tables 1 to 3 below, and 10 parts by mass of PGMEA (propylene glycol monomethyl ether acetate) was further mixed and uniformly dispersed using a high-speed rotary mixer to obtain a varnish-like resin composition. Details of each component shown in Tables 1 to 3 below are as follows.

[0240] (A) Epoxy Resins "807": Bisphenol F type epoxy resin, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight 160 to 175 g / eq. "EHPE3150": Epoxy resin having a structure represented by the following formula (A1) (epoxy resin having an alicyclic skeleton), manufactured by Daicel Corporation, epoxy equivalent weight approximately 177 g / eq.

[0241]

[0242] (In formula (A1), n ​​represents an integer of 1 to 30.)

[0243] "828": Bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 184 to 194 g / eq. "HP-7200H": Dicyclopentadiene type epoxy resin, manufactured by DIC Corporation, epoxy equivalent 265 to 300 g / eq. "YX8000": Hydrogenated bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 205 g / eq. "NC3000": Biphenyl type epoxy resin, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 270 to 300 g / eq.

[0244] (B) Photocurable Resin "M-208": bisphenol F type epoxy acrylate, manufactured by Toagosei Co., Ltd. "DPHA": dipentaerythritol hexaacrylate, manufactured by Daicel Allnex Corporation "M-211B": bisphenol A type epoxy acrylate, manufactured by Toagosei Co., Ltd. "A-DOG": dioxane glycol diacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd. "DABP": a compound having a structure represented by the following formula (B1), 4,4'-bisacryloxymethylbiphenyl, manufactured by JFE Chemical Corporation

[0245]

[0246] (C) Resins Having a Carboxyl Group and an Ethylenically Unsaturated Bond "ZFR-1491H": acid-modified bisphenol F type epoxy acrylate, manufactured by Nippon Kayaku Co., Ltd., acid value 99 mg KOH / g "RA-4104": acid-modified epoxy acrylate resin, manufactured by Negami Chemical Industrial Co., Ltd., acid value approximately 80 mg KOH / g "ZAR-2001H": acid-modified bisphenol A type epoxy acrylate, manufactured by Nippon Kayaku Co., Ltd., acid value 103 mg KOH / g "PCR-1173H": acid-modified phenol novolac type epoxy acrylate, manufactured by Nippon Kayaku Co., Ltd., acid value 98 mg KOH / g "UE-9350": acid-modified cresol novolac type epoxy acrylate, manufactured by DIC Corporation, acid value 70 mg KOH / g "(ACA) Z250": acrylic oligomer having a carboxyl group, manufactured by Daicel Allnex Corporation, acid value 69 mg KOH / g "Resin C": acid-modified epoxy acrylate resin C obtained in Synthesis Example 1, acid value 90 mg KOH / g

[0247] (D) Photopolymerization initiator "Omnirad 379EG": a compound having a structure represented by the following formula (D1), manufactured by IGM

[0248]

[0249] "Irgacure OXE-02": a compound having a structure represented by the following formula (D2), manufactured by BASF

[0250]

[0251] "Omnipol 910": a compound having a structure represented by the following formula (D3-1), manufactured by IGM

[0252]

[0253] (In formula (D3-1), R Ｘ is a group represented by the following formula (D3-2); and d represents an integer of 1 to 10.

[0254]

[0255] (In formula (C3-2), * represents a bond.)

[0256] (E) Thermal curing accelerator "1B2PZ": 2-phenyl-1-benzyl-1H-imidazole, manufactured by Shikoku Chemicals Corporation

[0257]

[0258]

[0259]

[0260] Test Example 1: Measurement of refractive index of cured product For component (A), component (B), and component (C), each component was applied to a silicon wafer to form a 10 μm-thick resin layer. Specifically, for components (B) and (C), 1 part of a PGMEA (propylene glycol monomethyl ether acetate) solution containing 20% ​​by mass of non-volatile components of a photopolymerization initiator ("Omnirad 379EG" manufactured by IMG) was added to 100 parts of each component, and the resulting solution was applied to the silicon wafer. For component (A), 1 part of an MEK (methyl ethyl ketone) solution containing 20% ​​by mass of non-volatile components of a thermal curing accelerator ("1B2PZ" manufactured by Shikoku Chemicals Corporation) was added to 100 parts of the component, and the resulting solution was applied to the silicon wafer. The formed resin layer was exposed to light using a projection exposure apparatus ("UX-2240" manufactured by Ushio Inc.) at a wavelength of 365 nm and an illuminance of 35 mW / cm. ２ and exposure dose 2 J / cm ２ After ultraviolet exposure under the conditions above, the film was placed in a clean oven and heated from room temperature to 190°C. After reaching 190°C, the film was subjected to a heat treatment for 90 minutes in an air atmosphere to cure the resin layer, thereby obtaining a cured product. The refractive index n (measurement wavelength: 1310 nm) of the obtained cured product was measured at room temperature and atmospheric pressure using a 2010M type prism coupler (manufactured by Metricon) with a 1310 nm laser beam.

[0261] Test Example 2: Evaluation of uniformity of refractive index difference of resin composition The uniformity of the refractive index of the resin composition was evaluated for the varnish-like resin compositions obtained in Production Examples 1 to 29. Specifically, the maximum refractive index value n of the cured product of each of the components (A), (B), and (C) contained in the resin composition was calculated. ｍａｘ and the minimum refractive index n ｍｉｎ When these differences (n ｍａｘ -nｍｉｎ ) was calculated. ｍａｘ -n ｍｉｎ In the cured product having a refractive index difference (n ) of 0.07 or more, the content X of the component that results in a refractive index difference of 0.07 or more at a wavelength of 1310 nm in the cured product of each of the components (A), (B), and (C) was calculated. The content X was calculated using the same calculation method as in steps (i) to (iv) described in the section [Resin composition]. ｍａｘ -n ｍｉｎ ) and the content X, the uniformity of the refractive index difference of the resin composition was evaluated according to the following evaluation criteria.

[0262] [Evaluation criteria for uniformity of refractive index difference of resin composition] "◎": The difference in refractive index (n ｍａｘ -n ｍｉｎ ) is less than 0.03. ｍａｘ -n ｍｉｎ ) is 0.03 or more and less than 0.04. ｍａｘ -n ｍｉｎ ) is 0.04 or more and less than 0.07, or the content X is more than 0 mass% and less than 10 mass%. ｍａｘ -n ｍｉｎ ) is 0.07 or more, and the content X is 10 mass% or more.

[0263] <Examples 1 to 26 and Comparative Examples 1 to 5: Formation of Optical Waveguide> The varnish-like resin compositions obtained in Production Examples 1 to 29 were used to obtain the optical waveguides of Examples 1 to 26 and Comparative Examples 1 to 5. In each of the Examples and Comparative Examples, the combinations of the core resin composition and the clad resin composition are as shown in Tables 4 to 8.

[0264] <Test Example 3: Measurement of Optical Transmission Loss> (1-1) Formation of Lower Cladding Layer In each Example and Comparative Example, the cladding resin composition was applied to a silicon wafer by spin coating so that the thickness of the resin composition layer after drying would be 10 μm. After application of the cladding resin composition, it was dried at 90° C. for 3 minutes to form a resin composition layer I. The resin composition layer I was exposed to a projection exposure apparatus ("UX-2240" manufactured by Ushio Inc.) at a wavelength of 365 nm and an illuminance of 35 mW / cm. ２ and exposure dose 2 J / cm２ After the ultraviolet exposure, the substrate was placed in a clean oven and heated from room temperature to 190°C. After the temperature reached 190°C, the substrate was subjected to a heat treatment for 90 minutes in an air atmosphere to cure the resin composition layer I, thereby forming a lower clad layer.

[0265] (1-2) Formation of Core Layer In each Example and Comparative Example, the core resin composition was applied onto the lower clad layer by spin coating so that the thickness of the resin composition layer after drying would be 5 μm. After application of the core resin composition, it was dried at 90° C. for 3 minutes to form a resin composition layer II. The resin composition layer II was exposed to light using a projection exposure apparatus (Ushio Inc.'s "UX-2240") at a wavelength of 365 nm and an illuminance of 35 mW / cm. ２ and exposure dose 2 J / cm ２ The resin composition layer II was then exposed to ultraviolet light at a wavelength of 365 nm and an illuminance of 35 mW / cm using a projection exposure apparatus (UX-2240 manufactured by Ushio Inc.). The exposure was performed using a quartz glass mask that drew multiple straight lines with a length of 5 cm and an L / S (line / space) of 5 μm / 100 μm. In the L / S of this quartz glass mask, the lines correspond to the width of the core layers, and the spaces correspond to the spacing between the core layers. The entire surface of the exposed resin composition layer II was subjected to spray development at a spray pressure of 0.2 MPa for 1 minute using a 1% by mass aqueous solution of sodium carbonate at 30°C as the developer. After spray development, the resin composition layer was exposed to ultraviolet light at a wavelength of 365 nm and an illuminance of 35 mW / cm using a projection exposure apparatus (UX-2240 manufactured by Ushio Inc.). ２ and exposure dose 2 J / cm ２ The core layer was formed by subjecting the silicon wafer to ultraviolet exposure and then to heat treatment at 190° C. for 1 hour in an air atmosphere. Through the above operations, an intermediate laminate A1 having a silicon wafer / lower clad layer / core layer in this order was obtained.

[0266] (1-3) Formation of Upper Clad Layer In each example and comparative example, the clad resin composition was applied by spin coating onto the core layer and lower clad layer of the intermediate laminate A1 so that the thickness of the resin composition layer after drying would be 10 μm. After application of the clad resin composition, it was dried at 90° C. for 3 minutes to form a resin composition layer III. After forming the resin composition layer III, it was exposed to light using a projection exposure apparatus ("UX-2240" manufactured by Ushio Inc.) at a wavelength of 365 nm and an illuminance of 35 mW / cm. ２ and exposure dose 2 J / cm２ The sample was then exposed to ultraviolet light. After the exposure, the sample was placed in a clean oven and heated from room temperature to 190°C. After reaching 190°C, a 90-minute heat treatment was performed in an air atmosphere to harden the resin composition layer III and form an upper clad layer. Through the above operations, a sample laminate A2 was obtained, which included a silicon wafer, a lower clad layer, a core layer, and an upper clad layer in this order. In this sample laminate A2, the combination of the lower clad layer and the upper clad layer constitutes the clad layer. Thus, an optical waveguide was obtained, which included the clad layer and a core layer within the clad layer.

[0267] (2) Preparation of Test Substrate From the sample laminate A2 produced by the above operation, the portion where the core layer was formed, i.e., the core layer on which a 5 cm linear pattern was drawn and the surrounding cladding layer, was cut out to obtain a test substrate A3 equipped with an optical transmission path. The cutting conditions were as follows: Dicing device: DAD3221 (manufactured by Disco Corporation) Blade: ZH14-SD4000-VI-50 Spindle rotation speed: 30 K / min Cutting speed: 5 mm / sec Blade height: 0.060 mm Dicing tape: T-80W (manufactured by Denka Company, 80 umt)

[0268] (3-1) Measurement of Optical Transmission Loss of Calibration Optical System As described below, the transmission loss of an optical system configured by excluding the test substrate A3 and the light-collecting module from the optical system for measuring the transmission loss of the test substrate A3 was measured. That is, a calibration optical system was obtained by connecting a light source (1310 nm light source, THORLABS's "LPSC-1310-FC") and a light receiver (Keysight's optical power meter "N7742") via an optical fiber (input fiber) on a vibration-isolating table covered with a blackout curtain. The light source was made to emit light, and the intensity of the light entering the receiver was measured with the receiver, thereby measuring the loss of this calibration optical system.

[0269] (3-2) Measurement of Optical Transmission Loss Test substrate A3 was placed on a vibration-isolating table covered with a blackout curtain. A focusing module (numerical aperture 0.18) was connected to one end (input end) of the optical waveguide of test substrate A3, and a light source (1310 nm light source, THORLABS's "LPSC-1310-FC") was connected to the focusing module via an optical fiber (input fiber). Another focusing module (numerical aperture 0.18) was connected to the other end (output end) of the optical waveguide of test substrate B4, and a light receiver (Keysight's optical power meter "N7742") was connected to the focusing module via an optical fiber (output fiber). Through these operations, an optical system was obtained in which light emitted from the light source passed through the optical fiber (input fiber), focusing module, optical waveguide, focusing module, and optical fiber (output fiber) in this order before entering the light receiver. Hereinafter, this optical system may be referred to as the "sample optical system." The light source was turned on and the intensity of the light that entered the receiver was measured by the receiver to measure the loss of the sample optical system.

[0270] The loss of the optical waveguide included in the test substrate A3 was determined by subtracting the loss of the calibration optical system from the loss of the sample optical system.

[0271] (3-3) Measurement of Optical Transmission Loss (dB / cm) of Optical Waveguides After completing the loss measurement for the 5 cm-long optical waveguide, the optical waveguide was cut to 4 cm and the same measurement was performed. Then, the optical waveguide was cut to 3 cm and the measurement was repeated, thereby calculating measured values ​​for the 5 cm-long optical waveguide, the 4 cm-long optical waveguide, and the 3 cm-long optical waveguide. The measurement results were then plotted on a coordinate system with the optical waveguide length on the horizontal axis and the optical waveguide loss on the vertical axis to obtain three coordinates representing the measurement results. An approximation line for these three points was calculated using the least squares method, and the slope of the approximation line was determined as the loss per unit distance of the optical waveguide (optical transmission loss). In each example and comparative example, measurements were performed on five optical waveguides, and the average value and standard deviation of the optical transmission loss of the optical waveguide were calculated. The calculated average value and standard deviation of the optical transmission loss were used to evaluate the optical transmission loss according to the following evaluation criteria.

[0272] [Evaluation criteria for average optical transmission loss] "◎": Average optical transmission loss is less than 0.30 dB / cm "〇": Average optical transmission loss is 0.30 dB / cm or more and less than 0.50 dB / cm "△": Average optical transmission loss is 0.50 dB / cm or more and less than 1.00 dB / cm "×": Average optical transmission loss is 1.00 dB / cm or more

[0273] [Evaluation criteria for standard deviation of optical transmission loss] "◎": Standard deviation of optical transmission loss is less than 0.003 "〇": Standard deviation of optical transmission loss is 0.003 or more and less than 0.020 "△": Standard deviation of optical transmission loss is 0.020 or more and less than 0.040 "×": Standard deviation of optical transmission loss is 0.040 or more

[0274]

[0275]

[0276]

[0277]

[0278]

[0279] 10 Optical waveguide 100 Core layer 100A Incident side end of core layer 100B Exit side end of core layer 100I Interface between core layer and clad layer 110 Second resin composition layer 111 Exposed portion of second resin composition layer 112 Non-exposed portion of second resin composition layer 200 Clad layer 210 First resin composition layer 220 First clad layer (cured first resin composition layer) 230 Third resin composition layer 240 Second clad layer (cured third resin composition layer) 300 Substrate 400 Mask 410 Light-transmitting portion of mask 420 Light-shielding portion of mask 500 Conductor layer P Light (actinic radiation)

Claims

1. A resin composition comprising (A) an epoxy resin, (B) a photocurable resin, (C) a resin having a carboxyl group and an ethylenically unsaturated bond, and (D) a photopolymerization initiator, wherein, in the cured product of each of components (A), (B), and (C), the content of components that result in a refractive index difference of 0.07 or more at a wavelength of 1,310 nm is less than 10% by mass when the total of components (A), (B), and (C) is taken as 100% by mass.

2. The maximum refractive index of the cured product of each of the components (A), (B), and (C) contained in the resin composition is n ｍａｘ The minimum value of the refractive index is n ｍｉｎ When 0≦n ｍａｘ -n ｍｉｎ The resin composition according to claim 1, which satisfies the relationship:

3. The resin composition according to claim 1, wherein component (A) comprises an epoxy resin having an alicyclic skeleton.

4. The resin composition according to claim 1, wherein component (D) includes a photoradical generator.

5. The resin composition according to claim 1, further comprising (E) a thermal curing accelerator.

6. A resin sheet comprising a support and a resin composition layer formed on the support, wherein the resin composition layer contains the resin composition according to any one of claims 1 to 5.

7. A resin composition set comprising a core resin composition and a clad resin composition, wherein the core resin composition and the clad resin composition each comprise the resin composition described in any one of claims 1 to 5.

8. The resin composition set according to claim 7, which is a resin composition set for producing an optical waveguide capable of transmitting light having a wavelength of 1300 nm to 1320 nm.

9. An optical waveguide comprising a core layer and a clad layer, wherein the core layer and the clad layer each comprise a cured product of the resin composition according to any one of claims 1 to 5.

10. The optical waveguide according to claim 9, which is capable of transmitting light having a wavelength of 1300 nm to 1320 nm.

11. An optical / electrical hybrid board comprising the optical waveguide according to claim 9.

12. A method for manufacturing an optical waveguide, comprising the steps of: forming a first resin composition layer containing a cladding resin composition; curing the first resin composition layer; forming a second resin composition layer containing a core resin composition on the first resin composition layer; subjecting the second resin composition layer to an exposure treatment; subjecting the second resin composition layer to a development treatment; curing the second resin composition layer; forming a third resin composition layer containing a cladding resin composition on the second resin composition layer; and curing the third resin composition layer, in this order; wherein the core resin composition and the cladding resin composition comprise the resin composition according to any one of claims 1 to 5.

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