Resin composition, resin film, film, film set, optical waveguide, photoelectric composite substrate and electronic component

Abstract

To provide a resin composition which improves embedding property and can suppress thermal deformation of an optical waveguide.SOLUTION: A resin composition which is usable in an optical waveguide clad contains a resin (A) having a norbornene structure, and a compound (B) having a cyclic ether structure, wherein the compound (B) having the cyclic ether structure contains two or more cyclic ether structures in the molecule, and has a functional group equivalent of 400 g / mol or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition, a resin film, a film, a film set, an optical waveguide, an optoelectronic composite substrate, and an electronic component. [Background technology]

[0002] BACKGROUND ART In recent years, there has been a demand for components in information and communication devices that can realize more advanced information communication, such as larger information capacity and faster information communication speed, and an optoelectronic composite substrate has been considered as one such component.

[0003] An example of an optical / electrical composite substrate is one in which an optical waveguide is provided on a substrate. Examples of techniques relating to optical and electrical composite substrates include those described in Patent Documents 1 and 2.

[0004] Patent document 1 describes an opto-electrical hybrid board comprising a flexible circuit board having electrical wiring with mounting pads formed on the surface of an insulating layer, an element mounted on the mounting pad, and an optical waveguide laminated on the back side of the insulating layer, wherein the flexible circuit board is a flexible double-sided circuit board having electrical wiring also formed on the back side of the insulating layer, and a metal reinforcing layer is plated on at least the portion of the electrical wiring on the back side that corresponds to the mounting pad, and the optical waveguide is in contact with the metal reinforcing layer. According to the opto-electrical hybrid board described in Patent Document 1, a metal reinforcing layer is adhered to the insulating layer of a flexible circuit board without an adhesive layer, and it is described that an opto-electrical hybrid board can be provided in which the metal reinforcing layer prevents deformation due to a pressure load when the element is mounted and the element is properly mounted.

[0005] Patent Document 2 describes an opto-electrical wiring board that is formed by integrating a rigid section in which conductor circuits and insulating layers are laminated on both sides of a substrate with one or more bendable flex sections, wherein the rigid section has external connection terminals formed therein for mounting optical elements and / or package substrates on which optical elements are mounted, and at least one of the flex sections has optical wiring formed therein. According to the optoelectronic wiring board of Patent Document 2, it is described that large amounts of information can be suitably processed and information can be processed at high speed without increasing the size of the wiring board. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-238455 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-140233 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention provides a resin composition that can improve embeddability and suppress thermal deformation of an optical waveguide. [Means for solving the problem]

[0008] According to the present invention, there are provided the following resin compositions, resin films, films, film sets, optical waveguides, optoelectronic composite substrates, and electronic components.

[0009] [1] A resin composition that can be used for an optical waveguide clad, The composition comprises a resin (A) having a norbornene structure and a compound (B) having a cyclic ether structure, The resin composition, wherein the compound (B) having a cyclic ether structure contains two or more cyclic ether structures in the molecule and has a functional group equivalent of 400 g / mol or less. [2] The resin composition according to [1] above, wherein the compound (B) having a cyclic ether structure includes at least one selected from the group consisting of epoxy compounds and oxetane compounds. [3] The resin composition according to [1] or [2] above, wherein the compound (B) having a cyclic ether structure contains an alicyclic structure in the molecule. [4] The resin composition according to any one of the above [1] to [3], wherein the compound (B) having a cyclic ether structure does not contain a siloxane bond in the main chain. [5] The resin composition according to any one of the above [1] to [4], wherein the compound (B) having a cyclic ether structure does not contain a trimethoxysilane skeleton. [6] The resin composition according to any one of the above [1] to [5], wherein the compound (B) having a cyclic ether structure does not contain a silicon atom. [7] The resin composition according to any one of the above [1] to [6], wherein the compound (B) having a cyclic ether structure is liquid at 23°C. [8] The resin composition according to any one of [1] to [7] above, wherein the refractive index of the compound (B) having a cyclic ether structure is 1.43 or more and 1.55 or less. [9] The resin composition according to any one of [1] to [8], wherein the content of the compound (B) having a cyclic ether structure in the resin composition is 5% by mass or more and 80% by mass or less, when the total content of non-volatile components in the resin composition is 100% by mass.

[10] The resin composition according to any one of [1] to [9] above, wherein the resin (A) having a norbornene structure contains a structural unit represented by the following formula (1): [ka] (In the formula (1), R represents a hydrogen atom, a hydroxyl group, or an organic group having 1 to 30 carbon atoms.)

[11] The resin composition according to

[10] above, wherein in the formula (1), R is any one selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 10 carbon atoms.

[12] The resin composition according to any one of [1] to

[11] above, wherein the resin (A) having a norbornene structure contains a structural unit represented by the following formula (2): [ka] (In the formula (2), X represents a divalent organic group having 1 to 30 carbon atoms, and Y represents a group having a cyclic ether structure.)

[13] The resin composition according to

[12] above, wherein the structural unit represented by formula (2) includes a structural unit represented by the following formula (2-1): [ka] (In the formula (2-1), a represents an integer of 0 or more and 3 or less, and b represents an integer of 1 or more and 3 or less.)

[14] The resin composition according to any one of [1] to

[13] above, wherein the resin (A) having a norbornene structure has a refractive index of 1.45 or more and 1.55 or less.

[15] The resin composition according to any one of [1] to

[14] , wherein the content of the resin (A) having a norbornene structure in the resin composition is 20% by mass or more and 95% by mass or less, when the total content of non-volatile components in the resin composition is 100% by mass.

[16] The resin composition according to any one of the above [1] to

[15] , further comprising a curing agent (C).

[17] The resin composition according to

[16] above, wherein the curing agent (C) contains a cationic polymerization initiator.

[18] The resin composition according to

[17] , wherein the cationic polymerization initiator includes a photocationic polymerization initiator.

[19] The resin composition according to any one of [1] to

[18] above, which has a refractive index of 1.47 or more and 1.55 or less.

[20] A resin film made of the resin composition according to any one of [1] to

[19] , The resin film has a light transmittance of 85% or more for a wavelength of 850 nm. [twenty one] The resin film according to

[20] above, having a thickness of 1 μm or more and 150 μm or less. [twenty two] A film comprising a resin layer formed from the resin composition according to any one of [1] to

[19] above. [twenty three] Further, a base film is provided, The film according to

[22] above, having the resin layer on the base film. [twenty four] The film according to

[23] above, wherein the resin constituting the base film includes at least one selected from the group consisting of polyimide and polyethylene terephthalate. [twenty five] The film according to any one of

[22] to

[24] above, wherein the film is a dry film.

[26] a first film and a second film, A film set, wherein at least one of the first film and the second film is the film according to any one of

[22] to

[25] above.

[27] An optical waveguide in which a first clad layer, a core layer, and a second clad layer are laminated in this order, An optical waveguide, wherein at least one of the first clad layer and the second clad layer comprises the resin composition according to any one of [1] to

[19] above.

[28] A substrate; An optical / electrical composite substrate comprising: the optical waveguide according to

[27] provided on the substrate.

[29] An electronic component comprising the optical / electrical composite substrate according to

[28] . [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a resin composition that can improve embeddability and suppress thermal deformation of an optical waveguide. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view schematically showing an example of the structure of an optoelectronic composite substrate according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the drawings are simplified and do not correspond to actual dimensional proportions. Numerical ranges "A to B" represent A or more and B or less unless otherwise specified.

[0013] FIG. 1 is a cross-sectional view showing a schematic example of the structure of an optoelectronic composite substrate according to this embodiment. As shown in FIG. 1, an optical / electrical composite substrate 200 has an optical waveguide 100 provided on a substrate 110. The optical waveguide 100 includes a first cladding layer 20, a core layer 30, and a second cladding layer 40 laminated in this order. A mirror 50 on the light-emitting element side and a mirror 60 on the light-receiving element side are formed on the optical waveguide 100. Vias 140 (140a, 140b) are formed in the substrate 110 (note that the via 140 shown in FIG. 1 is buried in the first cladding layer 20). A light-emitting element 120 and a light-receiving element 130 are provided on the side of the substrate 110 opposite the optical waveguide 100 side.

[0014] The propagation path of light in the optical / electrical composite substrate 200 will be specifically described using Figure 1. Light emitted from the light-emitting portion of the light-emitting element 120 passes through via 140a formed in the substrate 110, enters mirror 50 on the light-emitting element side, and after being transmitted through the core layer 30, enters mirror 60 on the light-receiving element side, passes through via 140b formed in the substrate 110, and enters light-receiving element 130. The arrows in Figure 1 are a schematic representation of the propagation of light.

[0015] An example of a method for providing the optical waveguide 100 on the substrate 110 is a method including a step of laminating the substrate 110, on which the via 140 is formed, and a film for forming the first cladding layer 20, and integrating them by heating and pressurizing. In the integration step, the via 140 needs to be embedded in the first cladding layer 20.

[0016] According to the inventors' investigations, it was found that conventional materials for forming optical waveguide claddings cannot sufficiently fill the optical waveguide claddings in the vias formed in the substrate, and that this can result in depressions on the surface of the optical waveguide cladding opposite the substrate side (i.e., the core layer side of the optical waveguide cladding) or voids in the vias. It was also found that when the above-mentioned depressions or voids occur in the optoelectronic composite substrate, optical loss occurs at the interfaces of the depressions or voids. In other words, a resin composition that can be used for the clad of an optical waveguide is required to have properties that enable the resin composition for the clad to be sufficiently embedded in vias.

[0017] Furthermore, mounting an optoelectronic composite substrate on an electronic component may include a process in which the optoelectronic composite substrate is exposed to high temperatures (e.g., 230°C to 270°C), such as a reflow soldering process. The inventors' investigations have revealed that in conventional optoelectronic composite substrates, exposure to high temperatures can cause thermal deformation of the optical waveguide. The inventors have also found that such thermal deformation of the optical waveguide can cause misalignment of the mirror. The inventors have also found that when the mirror is misaligned, light cannot propagate along the intended optical path, preventing normal light propagation. That is, a resin composition that can be used for the cladding of an optical waveguide is required to have the property of suppressing thermal deformation of the optical waveguide.

[0018] The present invention provides a resin composition that can improve embeddability and suppress thermal deformation of an optical waveguide.

[0019] [Resin composition] The resin composition of this embodiment is a resin composition that can be used for an optical waveguide clad, and contains a resin (A) having a norbornene structure and a compound (B) having a cyclic ether structure, and the compound (B) having a cyclic ether structure contains two or more cyclic ether structures in the molecule and has a functional group equivalent of 400 g / mol or less.

[0020] From the viewpoint of further improving the light propagation efficiency of the optical waveguide, the refractive index of the resin composition of this embodiment is preferably 1.55 or less, more preferably 1.54 or less, even more preferably 1.53 or less, and even more preferably 1.52 or less, and the lower limit is not particularly limited, but may be, for example, 1.47 or more, or 1.48 or more. Furthermore, from the viewpoint of further improving the light propagation efficiency of the optical waveguide, the refractive index of the resin composition of this embodiment is preferably 1.47 or more and 1.55 or less, more preferably 1.47 or more and 1.54 or less, even more preferably 1.47 or more and 1.53 or less, and even more preferably 1.48 or more and 1.52 or less. The refractive index of the resin composition means the refractive index measured for a resin film made of the resin composition using an Abbe refractometer under conditions of 23° C. and 589 nm. A resin film made of the resin composition can be produced, for example, by applying the resin composition onto a substrate film and drying it, as in the method described in the Examples.

[0021] From the viewpoint of further improving the light propagation efficiency of the optical waveguide, the light transmittance of the resin composition of this embodiment at a wavelength of 850 nm is preferably 85% or more and 100% or less, more preferably 90% or more and 100% or less, even more preferably 95% or more and 100% or less, even more preferably 97% or more and 100% or less, and even more preferably 98% or more and 100% or less. The light transmittance of the resin composition at a wavelength of 850 nm means the light transmittance value measured by an ultraviolet-visible spectrophotometer for a resin film made of the resin composition and having a thickness of 25 μm. A resin film made of a resin composition having a thickness of 25 μm can be produced, for example, by applying the resin composition onto a substrate film and drying it, as in the method described in the Examples.

[0022] The shape of the resin composition of the present embodiment is not particularly limited, and examples thereof include a film, membrane, varnish, and sheet.

[0023] Hereinafter, each of the constituent components of the resin composition of this embodiment will be described.

[0024] <Resin (A) Having a Norbornene Structure> The resin composition of the present embodiment contains a resin (A) having a norbornene structure.

[0025] The resin (A) having a norbornene structure preferably contains a structural unit represented by formula (1).

[0026] [ka]

[0027] In formula (1), R represents a hydrogen atom, a hydroxyl group, or an organic group having 1 to 30 carbon atoms.

[0028] In formula (1), the organic group constituting R is, for example, any one selected from the group consisting of an alkyl group, an alkenyl group, an alkynyl group, an alkylidene group, an aryl group, an aralkyl group, an alkaryl group, a cycloalkyl group, and an organic group having a carboxyl group. In formula (1), the organic group constituting R preferably excludes a group having a cyclic ether structure. Examples of the alkyl group include at least one selected from the group consisting of a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group. The alkenyl group may be, for example, at least one selected from the group consisting of an allyl group, a pentenyl group, a vinyl group, and the like. Examples of the alkynyl group include an ethynyl group. The alkylidene group may be, for example, at least one selected from the group consisting of a methylidene group, an ethylidene group, and the like. The aryl group may be, for example, at least one selected from the group consisting of a phenyl group, a naphthyl group, an anthracenyl group, and the like. The aralkyl group may be, for example, at least one selected from the group consisting of a benzyl group, a phenethyl group, and the like. The alkaryl group may be, for example, at least one selected from the group consisting of a tolyl group, a xylyl group, and the like. The cycloalkyl group may be, for example, at least one selected from the group consisting of an adamantyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, and the like.

[0029] In the organic group constituting R in formula (1), the alkyl group, alkenyl group, alkynyl group, alkylidene group, aryl group, aralkyl group, alkaryl group, cycloalkyl group, and organic group having a carboxyl group may have one or more hydrogen atoms substituted with halogen atoms, such as fluorine, chlorine, bromine, and iodine.

[0030] In formula (1), R is preferably any one selected from the group consisting of a hydrogen atom and an alkyl group, more preferably any one selected from the group consisting of a hydrogen atom and an alkyl group having from 1 to 10 carbon atoms, even more preferably any one selected from the group consisting of a hydrogen atom and an alkyl group having from 3 to 7 carbon atoms, even more preferably any one selected from the group consisting of a hydrogen atom and a straight-chain alkyl group having from 3 to 7 carbon atoms, and even more preferably any one selected from the group consisting of a hydrogen atom, an n-butyl group, and an n-hexyl group. In formula (1), when R is an alkyl group, the coatability of the resin composition can be further improved.

[0031] The resin (A) having a norbornene structure preferably contains a structural unit represented by formula (2).

[0032] [ka]

[0033] In formula (2), X represents a divalent organic group having 1 to 30 carbon atoms, and Y represents a group having a cyclic ether structure.

[0034] In formula (2), the divalent organic group having 1 to 30 carbon atoms is preferably a group containing an oxygen atom. In formula (2), the divalent organic group having 1 to 30 carbon atoms preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, and even more preferably 1 to 5 carbon atoms.

[0035] In formula (2), the group having a cyclic ether structure preferably includes at least one selected from the group consisting of a group containing an epoxy group and a group containing an oxetanyl group.

[0036] The structural unit represented by formula (2) preferably includes a structural unit represented by formula (2-1).

[0037] [ka]

[0038] In formula (2-1), a represents an integer of 0 or more and 3 or less, and b represents an integer of 1 or more and 3 or less. In formula (2-1), a is preferably 1 or 2, and more preferably 1. In formula (2-1), b is preferably 1 or 2, and more preferably 1.

[0039] The resin (A) having a norbornene structure preferably contains a structural unit represented by formula (1) and a structural unit represented by formula (2), and more preferably contains a structural unit represented by formula (1) and a structural unit represented by formula (2-1).

[0040] The resin (A) having a norbornene structure may contain structural units other than the structural units derived from norbornene-based compounds. Examples of other structural units include structural units derived from compounds having an ethylenic double bond and structural units derived from maleimide.

[0041] The content of structural units derived from norbornene-based compounds in the resin (A) having a norbornene structure is preferably 60 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, even more preferably 98 mol% or more, and even more preferably 100 mol%, when the total of all structural units in the resin (A) having a norbornene structure is taken as 100 mol%.

[0042] From the viewpoint of further improving the light propagation efficiency of the optical waveguide, the refractive index of the resin (A) having a norbornene structure is preferably 1.55 or less, more preferably 1.54 or less, and even more preferably 1.53 or less, and the lower limit is not particularly limited, but may be, for example, 1.45 or more, or 1.48 or more. Furthermore, from the viewpoint of further improving the light propagation efficiency of the optical waveguide, the refractive index of the resin (A) having a norbornene structure is preferably 1.45 or more and 1.55 or less, more preferably 1.45 or more and 1.54 or less, and even more preferably 1.48 or more and 1.53 or less. The refractive index of the resin (A) having a norbornene structure means the refractive index measured with an Abbe refractometer under conditions of 23° C. and 589 nm.

[0043] The weight average molecular weight (Mw) of the resin (A) having a norbornene structure is preferably 5,000 or more, more preferably 10,000 or more, and even more preferably 30,000 or more, from the viewpoint of further improving the heat resistance of the resin composition, and is preferably 200,000 or less, more preferably 100,000 or less, and even more preferably 80,000 or less, from the viewpoint of further improving the solubility in organic solvents. From the viewpoint of further improving the performance balance between the heat resistance and solubility in organic solvents of the resin composition, it is preferably 5,000 or more and 200,000 or less, more preferably 10,000 or more and 100,000 or less, and even more preferably 30,000 or more and 80,000 or less. The weight average molecular weight (Mw) of the resin (A) having a norbornene structure means a value determined by gel permeation chromatography (GPC) using polystyrene as a standard substance.

[0044] The content of the resin (A) having a norbornene structure in the resin composition of this embodiment is preferably 20% by mass or more and 95% by mass or less, more preferably 25% by mass or more and 90% by mass or less, and even more preferably 28% by mass or more and 85% by mass or less, from the viewpoint of further improving embeddability and further suppressing thermal deformation of the optical waveguide, when the total content of non-volatile components in the resin composition is taken as 100% by mass.

[0045] The resin (A) having a norbornene structure can be produced, for example, by a known method, and more specifically, can be produced by polymerizing monomers capable of forming each structural unit by any method. Monomers capable of forming each structural unit include, for example, at least one selected from the group consisting of 2-norbornene, n-butylnorbornene, n-hexylnorbornene, 2-[(bicyclo[2.2.1]hept-5-en-2-ylmethoxy)methyl]oxirane, and (3-ethyloxetan-3-yl)methyl bicyclo[2.2.1]hept-5-ene-2-carboxylate.

[0046] The resin (A) having a norbornene structure may be a resin having one type of norbornene structure, or may contain two or more types of resins having a norbornene structure.

[0047] <Compound (B) Having a Cyclic Ether Structure> The resin composition of this embodiment contains a compound (B) having a cyclic ether structure, and the compound (B) having a cyclic ether structure contains two or more cyclic ether structures in the molecule and has a functional group equivalent of 400 g / mol or less.

[0048] The compound (B) having a cyclic ether structure is a compound containing two or more cyclic ether structures in the molecule, and preferably contains two or three cyclic ether structures in the molecule.

[0049] The compound (B) having a cyclic ether structure has a functional group equivalent of 400 g / mol or less, and from the viewpoint of further suppressing thermal deformation of the optical waveguide, it is preferably 300 g / mol or less, more preferably 250 g / mol or less, even more preferably 230 g / mol or less, and even more preferably 210 g / mol or less. The lower limit is not particularly limited, but may be, for example, 50 g / mol or more, 75 g / mol or more, or 100 g / mol or more. Furthermore, from the viewpoint of further suppressing thermal deformation of the optical waveguide, the compound (B) having a cyclic ether structure has a functional group equivalent of preferably 50 g / mol to 400 g / mol, more preferably 75 g / mol to 300 g / mol, even more preferably 100 g / mol to 250 g / mol, even more preferably 100 g / mol to 230 g / mol, and even more preferably 100 g / mol to 210 g / mol. Here, the functional group equivalent of the compound having a cyclic ether structure means the number of grams of the compound having a cyclic ether structure corresponding to 1 mol of the cyclic ether structure. For example, when the compound having a cyclic ether structure is an epoxy compound, the functional group equivalent means the epoxy equivalent.

[0050] The compound (B) having a cyclic ether structure preferably includes at least one selected from the group consisting of epoxy compounds and oxetane compounds.

[0051] The compound (B) having a cyclic ether structure preferably contains an alicyclic structure in the molecule. Here, the compound (B) having a cyclic ether structure containing an alicyclic structure in the molecule means that it contains an alicyclic structure in addition to the cyclic ether structure. However, the alicyclic structure in this embodiment includes a fused ring structure in which a cyclic ether and an aliphatic ring are fused, and a spiro ring structure in which a cyclic ether and an aliphatic ring are bonded via a spiro bond atom. The number of ring members in the alicyclic structure is not particularly limited, but is preferably a 4-membered ring to 10-membered ring, more preferably a 4-membered ring to 8-membered ring, even more preferably a 5-membered ring or a 6-membered ring, and even more preferably a 6-membered ring.

[0052] The compound (B) having a cyclic ether structure preferably does not contain a siloxane bond in the main chain. The compound (B) having a cyclic ether structure preferably does not contain a trimethoxysilane skeleton. The compound (B) having a cyclic ether structure preferably does not contain a silicon atom.

[0053] The compound (B) having a cyclic ether structure is preferably liquid at 23° C., from the viewpoint of further improving embeddability and further improving handleability when producing a resin composition.

[0054] From the viewpoint of further improving the light propagation efficiency of the optical waveguide, the refractive index of the compound (B) having a cyclic ether structure is preferably 1.55 or less, more preferably 1.53 or less, and even more preferably 1.52 or less, and the lower limit is not particularly limited, but may be, for example, 1.43 or more or 1.44 or more. Furthermore, from the viewpoint of further improving the light propagation efficiency of the optical waveguide, the refractive index of the compound (B) having a cyclic ether structure is preferably 1.43 or more and 1.55 or less, more preferably 1.43 or more and 1.53 or less, and even more preferably 1.44 or more and 1.52 or less. The refractive index of the compound (B) having a cyclic ether structure means the refractive index measured with an Abbe refractometer under the conditions of 23° C. and 589 nm.

[0055] The content of the compound (B) having a cyclic ether structure in the resin composition of this embodiment is preferably 5% by mass or more and 80% by mass or less, more preferably 10% by mass or more and 75% by mass or less, and even more preferably 15% by mass or more and 72% by mass or less, from the viewpoint of further improving embeddability and further suppressing thermal deformation of the optical waveguide, when the total content of non-volatile components in the resin composition is taken as 100% by mass.

[0056] The compound (B) having a cyclic ether structure may be a compound having one type of cyclic ether structure, or may contain compounds having two or more types of cyclic ether structures.

[0057] <Curing agent (C)> The resin composition of the present embodiment preferably further contains a curing agent (C). The curing agent (C) may be, for example, at least one selected from the group consisting of a thermal polymerization initiator, a photopolymerization initiator, an amine compound, and the like.

[0058] The curing agent (C) preferably contains a cationic polymerization initiator, and more preferably contains a photocationic polymerization initiator.

[0059] The photocationic polymerization initiator includes, for example, at least one selected from the group consisting of sulfonium salt-type polymerization initiators and iodonium salt-type polymerization initiators, and preferably includes a sulfonium salt-type polymerization initiator, more preferably includes a triarylsulfonium salt-type polymerization initiator, and even more preferably includes a triphenylsulfonium salt-type polymerization initiator.

[0060] The curing agent (C) more preferably includes a photocationic polymerization initiator and a thermal cationic polymerization initiator. The thermal cationic polymerization initiator includes, for example, at least one selected from the group consisting of sulfonium salt type polymerization initiators and iodonium salt type polymerization initiators, and preferably includes a sulfonium salt type polymerization initiator.

[0061] The amine compound preferably includes an imidazole compound. The imidazole compound means a compound containing an imidazole ring structure, and includes, for example, a compound in which hydrogen atoms of imidazole are substituted with hydrocarbon groups or the like.

[0062] The content of the curing agent (C) in the resin composition of this embodiment is preferably 0.01 parts by mass or more and 1.0 parts by mass or less, more preferably 0.05 parts by mass or more and 0.7 parts by mass or less, and even more preferably 0.1 parts by mass or more and 0.5 parts by mass or less, when the total content of the resin (A) having a norbornene structure and the compound (B) having a cyclic ether structure in the resin composition is 100 parts by mass.

[0063] The curing agent (C) of the present embodiment may contain one type of curing agent, or may contain two or more types of curing agents.

[0064] <Surfactant (D)> From the viewpoint of further improving embeddability, the resin composition of the present embodiment preferably further contains a surfactant (D). The surfactant (D) includes, for example, at least one selected from the group consisting of silicone surfactants and fluorine-based surfactants, and preferably includes a silicone surfactant. The surfactant (D) of the present embodiment may be a single surfactant or may contain two or more surfactants.

[0065] The content of the surfactant (D) in the resin composition of this embodiment is preferably 0.01 parts by mass or more and 3.0 parts by mass or less, more preferably 0.05 parts by mass or more and 1.0 parts by mass or less, and even more preferably 0.1 parts by mass or more and 0.5 parts by mass or less, when the total content of the resin (A) having a norbornene structure and the compound (B) having a cyclic ether structure in the resin composition is 100 parts by mass.

[0066] <Organic solvent (E)> The resin composition of the present embodiment may contain an organic solvent (E). When the resin composition of the present embodiment contains an organic solvent (E), it can be made into a varnish-like resin composition.

[0067] The organic solvent (E) of the present embodiment includes at least one selected from the group consisting of, for example, acetone, methyl ethyl ketone, methyl amyl ketone, toluene, propylene glycol monomethyl ether, propylene glycol methyl ethyl ether, propylene glycol dimethyl ether, propylene glycol 1-monomethyl ether 2-acetate, diethylene glycol ethyl methyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, benzyl alcohol, propylene carbonate, ethylene glycol diacetate, propylene glycol diacetate, propylene glycol monomethyl ether acetate, dipropylene glycol methyl-n-propyl ether, butyl acetate, γ-butyrolactone, methyl lactate, ethyl lactate, and butyl lactate. The organic solvent (E) of the present embodiment may be a single organic solvent, or may contain two or more organic solvents.

[0068] When the resin composition of the present embodiment contains an organic solvent (E), the concentration of all solids (non-volatile components) in the resin composition is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and even more preferably 35% by mass or more, from the viewpoint of appropriately controlling the viscosity of the resin composition, and is preferably 60% by mass or less, more preferably 55% by mass or less, and even more preferably 50% by mass or less, from the viewpoint of sufficiently dissolving each component in the resin composition.

[0069] <Other ingredients> The resin composition of the present embodiment may further contain, for example, a curing aid, a leveling agent, a colorant, a storage stabilizer, a plasticizer, a filler, inorganic particles, an antidegradant, a wettability improver, an antistatic agent, etc. The content of other components is an appropriate amount.

[0070] The total content of the resin (A) having a norbornene structure and the compound (B) having a cyclic ether structure in the resin composition of this embodiment is preferably 80% by mass or more and less than 100% by mass, more preferably 90% by mass or more and less than 100% by mass, and even more preferably 95% by mass or more and less than 100% by mass, from the viewpoint of further improving embeddability and further suppressing thermal deformation of the optical waveguide, when the total content of non-volatile components in the resin composition is taken as 100% by mass. The total content of the resin (A) having a norbornene structure and the compound (B) having a cyclic ether structure in the resin composition of this embodiment, when the total content of all components in the resin composition is taken as 100% by mass, is preferably 10% by mass or more and less than 100% by mass, more preferably 20% by mass or more and less than 100% by mass, even more preferably 30% by mass or more and less than 100% by mass, even more preferably 35% by mass or more and less than 100% by mass, even more preferably 50% by mass or more and less than 100% by mass, even more preferably 70% by mass or more and less than 100% by mass, even more preferably 80% by mass or more and less than 100% by mass, even more preferably 85% by mass or more and less than 100% by mass, even more preferably 90% by mass or more and less than 100% by mass, and even more preferably 95% by mass or more and less than 100% by mass.

[0071] [Method of producing resin composition] The resin composition of the present embodiment can be obtained, for example, by mixing the components. The film-like resin composition of this embodiment can be obtained, for example, by applying a varnish-like resin composition onto a substrate film and drying it.

[0072] [Resin film] The resin film of this embodiment is made of the resin composition of this embodiment. The resin film of this embodiment includes not only a resin film alone but also a resin film formed on a substrate film.

[0073] From the viewpoint of further improving the light propagation efficiency of the optical waveguide, the light transmittance of the resin film of this embodiment at a wavelength of 850 nm is preferably 85% or more and 100% or less, more preferably 90% or more and 100% or less, even more preferably 95% or more and 100% or less, even more preferably 97% or more and 100% or less, and even more preferably 98% or more and 100% or less. The light transmittance of the resin film at a wavelength of 850 nm means the value of the light transmittance measured by an ultraviolet-visible spectrophotometer.

[0074] The thickness of the resin film in this embodiment is preferably 1 μm or more, more preferably 3 μm or more, even more preferably 5 μm or more, and even more preferably 8 μm or more, from the viewpoint of further improving embeddability, and is preferably 150 μm or less, more preferably 130 μm or less, even more preferably 100 μm or less, even more preferably 70 μm or less, even more preferably 50 μm or less, and even more preferably 30 μm or less, from the viewpoint of further improving embeddability and light propagation efficiency of the optical waveguide, and is preferably 1 μm or more and 150 μm or less, more preferably 3 μm or more and 130 μm or less, even more preferably 5 μm or more and 100 μm or less, even more preferably 8 μm or more and 70 μm or less, even more preferably 8 μm or more and 50 μm or less, and even more preferably 8 μm or more and 30 μm or less.

[0075] The resin film of this embodiment can be obtained by a known method for forming a coating film using, for example, the varnish-like resin composition of this embodiment as a raw material.

[0076] [film] The film of this embodiment includes a resin layer formed from the resin composition of this embodiment. The film of this embodiment is preferably a dry film.

[0077] The resin composition forming the resin layer of the present embodiment may be an uncured product, a semi-cured product, or a cured product, but is preferably a semi-cured product.

[0078] From the viewpoint of further improving the handleability of the film, the thickness of the film of this embodiment is preferably 10 μm or more and 250 μm or less, more preferably 30 μm or more and 200 μm or less, even more preferably 40 μm or more and 150 μm or less, even more preferably 60 μm or more and 140 μm or less, and even more preferably 80 μm or more and 130 μm or less.

[0079] The thickness of the resin layer in this embodiment is preferably 1 μm or more, more preferably 3 μm or more, even more preferably 5 μm or more, and even more preferably 8 μm or more, from the viewpoint of further improving embeddability, and is preferably 150 μm or less, more preferably 130 μm or less, even more preferably 100 μm or less, even more preferably 70 μm or less, even more preferably 50 μm or less, and even more preferably 30 μm or less, from the viewpoint of further improving embeddability and light propagation efficiency of the optical waveguide, and is preferably 1 μm or more and 150 μm or less, more preferably 3 μm or more and 130 μm or less, even more preferably 5 μm or more and 100 μm or less, even more preferably 8 μm or more and 70 μm or less, even more preferably 8 μm or more and 50 μm or less, and even more preferably 8 μm or more and 30 μm or less.

[0080] The film of the present embodiment preferably further includes a substrate film and has a resin layer on the substrate film. The base film may be, for example, a resin film. The resin constituting the base film is not particularly limited, but preferably contains at least one selected from the group consisting of polyimide and polyethylene terephthalate.

[0081] From the viewpoint of further improving the handleability of the film, the thickness of the base film of this embodiment is preferably 10 μm or more and 100 μm or less, more preferably 15 μm or more and 80 μm or less, even more preferably 20 μm or more and 60 μm or less, and even more preferably 20 μm or more and 40 μm or less.

[0082] The substrate film of the present embodiment may be subjected to a surface treatment such as an antistatic treatment or a release treatment.

[0083] The film of this embodiment may further include a cover film, which is preferably provided so as to be in direct contact with the resin layer. When the film of this embodiment includes a base film, the cover film is preferably provided on the surface of the resin layer opposite to the base film. The cover film is not particularly limited, but for example, an OPP cover film can be used.

[0084] The film of this embodiment can be obtained, for example, by applying the varnish-like resin composition of this embodiment to a substrate film and drying it. Examples of the application method include direct application using various coater devices such as a pin coater, a die coater, a comma coater, and a curtain coater, and printing methods such as screen printing.

[0085] [Film Set] The film set of this embodiment includes a first film and a second film, and at least one of the first film and the second film is the film of this embodiment.

[0086] In the film set of this embodiment, when the first film is a film that can be used for the first clad layer 20 in Figure 1 and the second film is a film that can be used for the second clad layer 40 in Figure 1, preferably the first film is a film of this embodiment, and more preferably both the first film and the second film are films of this embodiment.

[0087] [Optical waveguide] The optical waveguide of this embodiment will be described with reference to FIG. The optical waveguide 100 of this embodiment is an optical waveguide in which a first clad layer 20, a core layer 30, and a second clad layer 40 are stacked in this order, and at least one of the first clad layer 20 and the second clad layer 40 contains the resin composition of this embodiment. In this specification, when the optical waveguide 100 is provided on the substrate 110, the cladding layer located on the substrate 110 side is referred to as the first cladding layer 20. Furthermore, hereinafter, when simply referring to a "cladding layer," this concept includes both the first cladding layer 20 and the second cladding layer 40.

[0088] In the optical waveguide 100 of this embodiment, the first clad layer 20 preferably contains the resin composition of this embodiment, and more preferably both the first clad layer 20 and the second clad layer 40 contain the resin composition of this embodiment.

[0089] The resin composition contained in the cladding layer of this embodiment may be an uncured product, a semi-cured product, or a cured product, but is preferably a cured product.

[0090] From the viewpoint of further improving embeddability, the thickness of the first cladding layer 20 is preferably 1 μm or more, more preferably 3 μm or more, even more preferably 5 μm or more, even more preferably 8 μm or more, even more preferably 10 μm or more, even more preferably 15 μm or more, and even more preferably 20 μm or more; from the viewpoint of further improving the light propagation efficiency of the optical waveguide, the thickness is preferably 150 μm or less, more preferably 100 μm or less, even more preferably 70 μm or less, even more preferably 50 μm or less, even more preferably 40 μm or less, and even more preferably 30 μm or less; and from the viewpoint of further improving embeddability and the light propagation efficiency of the optical waveguide, the thickness is preferably 1 μm or more and 150 μm or less, more preferably 3 μm or more and 100 μm or less, even more preferably 5 μm or more and 70 μm or less, even more preferably 8 μm or more and 50 μm or less, even more preferably 10 μm or more and 40 μm or less, even more preferably 15 μm or more and 30 μm or less.

[0091] From the viewpoint of further suppressing thermal deformation of the optical waveguide, the thickness of the second cladding layer 40 is preferably 1 μm or more and 150 μm or less, more preferably 3 μm or more and 100 μm or less, even more preferably 5 μm or more and 70 μm or less, even more preferably 8 μm or more and 50 μm or less, and even more preferably 8 μm or more and 20 μm or less.

[0092] The material for forming the core layer 30 is not particularly limited, but may be formed from, for example, a resin composition. The resin for forming the core layer 30 includes, for example, a resin used for the core of a known optical waveguide, preferably a cyclic olefin resin, and more preferably a norbornene resin. The resin composition for forming the core layer 30 may contain an antioxidant, a photocationic polymerization initiator, and the like.

[0093] The thickness of the core layer 30 is preferably 1 μm or more and 100 μm or less, more preferably 5 μm or more and 80 μm or less, even more preferably 10 μm or more and 60 μm or less, and even more preferably 30 μm or more and 50 μm or less.

[0094] A waveguide pattern may be formed in the core layer 30. Methods for forming the waveguide pattern include, for example, exposure, etching, and replication.

[0095] The optical waveguide 100 may have a mirror formed thereon, and may have a mirror 50 on the light-emitting element side and a mirror 60 on the light-receiving element side. The mirrors may be formed, for example, by forming an inclined surface by laser processing or the like.

[0096] The optical waveguide 100 may include other layers in addition to the first cladding layer 20, the core layer 30, and the second cladding layer 40, as long as the excellent performance of the optical waveguide 100 is not affected.

[0097] [Optical / electrical composite substrate] The optical and electrical composite substrate of this embodiment will be described with reference to FIG. The optical / electrical composite substrate 200 includes a substrate 110 and an optical waveguide 100 provided on the substrate 110 .

[0098] The substrate 110 may be, for example, a printed circuit board or a flexible substrate, and is preferably a flexible substrate. The substrate 110 may have vias 140 formed therein.

[0099] The optical / electrical composite substrate 200 may further include a polyimide base material (not shown) on the surface of the second cladding layer 40 opposite to the core layer 30 side.

[0100] The optical / electrical composite substrate 200 may include a light emitting element 120, a light receiving element 130, and the like.

[0101] The optical-electrical composite substrate 200 can be obtained, for example, by (i) forming a first clad layer 20 on the substrate 110, (ii) forming a core layer 30 on the first clad layer 20, and (iii) forming a second clad layer 40 on the core layer 30. Examples of methods for forming each layer include methods in which films for forming each layer are laminated in order by roll lamination, vacuum roll lamination, flat plate lamination, vacuum flat plate lamination, atmospheric pressing, vacuum pressing, etc.

[0102] [Electronic Components] The electronic component of this embodiment includes the optical / electrical composite substrate of this embodiment. Examples of the electronic component of this embodiment include electronic components in electronic devices such as mobile phones, game machines, router devices, WDM devices, personal computers, televisions, and home servers.

[0103] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted. Furthermore, the present invention is not limited to the above-described embodiment, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention. [Example]

[0104] The present embodiment will be described in detail below based on examples and comparative examples, but the present embodiment is not limited to the descriptions of these examples.

[0105] [Raw materials] First, the raw materials used in the examples and comparative examples will be described.

[0106] <Synthesis of resins containing norbornene structures> (Synthesis of Resin (A-1) Having a Norbornene Structure) A reaction vessel equipped with a stirrer and a condenser was prepared. The inside of the vessel was first thoroughly purged with nitrogen. Then, 124.8 g (0.7 mol) of n-hexylnorbornene, 54.1 g (0.3 mol) of 2-[(bicyclo[2.2.1]hept-5-en-2-ylmethoxy)methyl]oxirane, and 440 g of toluene were charged and heated to 50 °C in an oil bath while stirring. A solution of 29.9 g (0.02 mol) of (toluene)Ni(CF) in 5 g of toluene was added, and the reaction was continued for 3 hours at 50 °C. The resulting solution was reprecipitated in a large amount of methanol to obtain a polymer precipitate, which was then filtered using a suction filter to obtain a polymer powder. The resulting polymer was vacuum dried at 60 °C for 16 hours to obtain a resin (A-1) having a norbornene structure. The weight average molecular weight (Mw) of the resin (A-1) having a norbornene structure measured by GPC was 50,000, and the refractive index of the resin (A-1) having a norbornene structure measured by an Abbe refractometer at 23°C and 589 nm was 1.51.

[0107] (Synthesis of Resin (A-2) Having a Norbornene Structure) A reaction vessel equipped with a stirrer and a condenser was prepared. The inside of the vessel was first thoroughly purged with nitrogen. Then, 105.2 g (0.7 mol) of n-butylnorbornene, 54.1 g (0.3 mol) of 2-[(bicyclo[2.2.1]hept-5-en-2-ylmethoxy)methyl]oxirane, and 395 g of toluene were charged and heated to 50 °C in an oil bath while stirring. A solution of 29.9 g (0.02 mol) of (toluene)Ni(CF) in 5 g of toluene was added, and the reaction was continued for 3 hours at 50 °C. The resulting solution was reprecipitated in a large amount of methanol to obtain a polymer precipitate, which was then filtered using a suction filter to obtain a polymer powder. The resulting polymer was vacuum dried at 60 °C for 16 hours to obtain a resin (A-2) having a norbornene structure. The weight average molecular weight (Mw) of the resin (A-2) having a norbornene structure measured by GPC was 55,000, and the refractive index of the resin (A-2) having a norbornene structure measured by an Abbe refractometer at 23°C and 589 nm was 1.52.

[0108] (Synthesis of Resin (A-3) Having a Norbornene Structure) A reaction vessel equipped with a stirrer and a condenser was prepared. The inside of the vessel was first thoroughly purged with nitrogen. Then, 124.8 g (0.7 mol) of n-hexylnorbornene, 70.9 g (0.3 mol) of (3-ethyloxetan-3-yl)methyl bicyclo[2.2.1]hept-5-ene-2-carboxylate, and 480 g of toluene were added and heated to 50 °C in an oil bath while stirring. A solution of 29.9 g (0.02 mol) of (toluene)Ni(CF) dissolved in 5 g of toluene was added and the reaction continued for 3 hours at 50 °C. The resulting solution was reprecipitated in a large amount of methanol to obtain a polymer precipitate, which was then filtered using a suction filter to obtain a polymer powder. The resulting polymer was then vacuum dried at 60 °C for 16 hours to obtain a resin (A-3) having a norbornene structure. The weight average molecular weight (Mw) of the resin (A-3) having a norbornene structure measured by GPC was 45,000, and the refractive index of the resin (A-3) having a norbornene structure measured by an Abbe refractometer at 23°C and 589 nm was 1.52.

[0109] (Synthesis of Resin (A-4) Having a Norbornene Structure) A reaction vessel equipped with a stirrer and a condenser was prepared. The inside of the vessel was first thoroughly purged with nitrogen. Then, 47.1 g (0.5 mol) of 2-norbornene, 90.1 g (0.5 mol) of 2-[(bicyclo[2.2.1]hept-5-en-2-ylmethoxy)methyl]oxirane, and 343 g of toluene were charged and heated to 50 °C in an oil bath while stirring. A solution of 29.9 g (0.02 mol) of (toluene)Ni(CF) dissolved in 5 g of toluene was added, and the reaction was continued for 3 hours at 50 °C. The resulting solution was reprecipitated in a large amount of methanol to obtain a polymer precipitate, which was then filtered using a suction filter to obtain a polymer powder. The resulting polymer was vacuum dried at 60 °C for 16 hours to obtain a resin (A-4) having a norbornene structure. The weight average molecular weight (Mw) of the resin (A-4) having a norbornene structure measured by GPC was 60,000, and the refractive index of the resin (A-4) having a norbornene structure measured by an Abbe refractometer at 23°C and 589 nm was 1.50.

[0110] (Synthesis of Resin (A-5) Having a Norbornene Structure) A reaction vessel equipped with a stirrer and a condenser was prepared. The inside of the vessel was first thoroughly purged with nitrogen. Then, 124.8 g (0.7 mol) of n-hexylnorbornene, 28.2 g (0.3 mol) of 2-norbornene, and 380 g of toluene were charged and heated to 50 °C in an oil bath while stirring. A solution of 29.9 g (0.02 mol) of (toluene)Ni(CF) dissolved in 5 g of toluene was added, and the reaction was continued for 3 hours at 50 °C. The resulting solution was reprecipitated in a large amount of methanol to obtain a polymer precipitate, which was then filtered using a suction filter to obtain a polymer powder. The resulting polymer was vacuum dried at 60 °C for 16 hours to obtain a resin (A-5) having a norbornene structure. The weight average molecular weight (Mw) of the resin (A-5) having a norbornene structure measured by GPC was 60,000, and the refractive index of the resin (A-5) having a norbornene structure measured by an Abbe refractometer at 23°C and 589 nm was 1.50.

[0111] Details of the raw materials for each component in Table 1 are as follows:

[0112] <Resin (A) Having a Norbornene Structure> (A-1) Resin having a norbornene structure synthesized above (A-2) Resin having a norbornene structure synthesized above (A-3) Resin having a norbornene structure synthesized above (A-4) Resin having a norbornene structure synthesized above (A-5) Resin having a norbornene structure synthesized above

[0113] [ka]

[0114] <Compound (B) Having a Cyclic Ether Structure> (B-1) JER-YX8034 (manufactured by Mitsubishi Chemical Corporation, epoxy compound having two functional groups, liquid at 23°C, refractive index 1.51, epoxy equivalent 270 g / mol) (B-2) Denacol EX-321L (manufactured by Nagase ChemteX Corporation, epoxy compound having two or three functional groups, liquid at 23°C, refractive index 1.50, epoxy equivalent 130 g / mol) (B-3) OXT-221 (manufactured by Toagosei Co., Ltd., an oxetane compound having two functional groups, liquid at 23°C, refractive index 1.45, oxetane equivalent 107 g / mol) (B-4) 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., an epoxy compound having one functional group) (for comparative example) (B-5) X-22-169AS (Shin-Etsu Chemical Co., Ltd., epoxy silicone resin, epoxy equivalent 500 g / mol) (for comparison)

[0115] [ka]

[0116] <Curing agent (C)> (C-1) CPI-310B (San-Apro Co., Ltd., photocationic polymerization initiator) (C-2) San-Aid SI-B5 (manufactured by Sanshin Chemical Industry Co., Ltd., thermal cationic polymerization initiator)

[0117] <Surfactant (D)> (D-1) BYK-333 (BYK Japan Co., Ltd., silicone surfactant)

[0118] <Organic solvent (E)> (E-1) Toluene

[0119] [Examples 1 to 7 and Comparative Examples 1 to 3] (Preparation of Resin Composition) The raw materials formulated according to Table 1 were stirred at room temperature until the raw materials were completely dissolved to obtain a solution, which was then filtered through a PTFE filter with a pore size of 0.2 μm to obtain varnish-like resin compositions of Examples 1 to 7 and Comparative Examples 1 to 3, respectively.

[0120] (Preparation of film for forming first clad layer) The resin compositions of Examples 1 to 7 and Comparative Examples 1 to 3 obtained by preparing the above resin compositions were applied as a varnish using an applicator onto a 38 μm thick antistatic treated polyethylene terephthalate substrate so that the thickness after drying would be the thickness of the resin layer shown in Table 1, and then dried at 100°C for 10 minutes.Finally, an OPP cover film was attached to the surface of the resin layer formed by the resin composition to create a film, thereby obtaining the films of Examples 1 to 7 and Comparative Examples 1 to 3, respectively.

[0121] (Preparation of dry film for core layer formation) (Synthesis of polymer for forming core layer) In a glove box filled with dry nitrogen and with moisture and oxygen concentrations both controlled to 1 ppm or less, 7.2 g (40.1 mmol) of hexylnorbornene (HxNB) and 12.9 g (40.1 mmol) of diphenylmethylnorbornene methoxysilane were weighed into a 500 mL vial, to which 60 g of dehydrated toluene and 11 g of ethyl acetate were added, and the vial was then sealed with a silicone sealer. Next, 1.56 g (3.2 mmol) of Ni catalyst and 10 mL of dehydrated toluene were weighed into a 100 mL vial, the vial was sealed with a stirrer tip, and the Ni catalyst was thoroughly stirred to completely dissolve, yielding a Ni catalyst solution. 1 mL of the Ni catalyst solution was accurately measured with a syringe and quantitatively injected into the vial containing the two norbornenes dissolved above. Stirring was continued at room temperature for 1 hour, resulting in a significant increase in viscosity. At this point, the stopper was removed, and 60 g of tetrahydrofuran (THF) was added and stirred to obtain a reaction solution. A 100 mL beaker was charged with 9.5 g of acetic anhydride, 18 g of hydrogen peroxide (30% concentration), and 30 g of ion-exchanged water, and the resulting mixture was stirred to prepare an aqueous solution of peracetic acid. The entire amount of the aqueous solution of peracetic acid was then added to the reaction solution and stirred for 12 hours to reduce Ni. Next, the reaction solution was transferred to a separatory funnel, and after removing the lower aqueous layer, 100 mL of a 30% aqueous solution of isopropyl alcohol was added and vigorously stirred. After allowing the mixture to stand and completely separate into two layers, the aqueous layer was removed. This water washing process was repeated three times, and the oil layer was then dropped into a large excess of acetone to reprecipitate the resulting polymer. The filtrate was separated by filtration and then heated and dried for 12 hours in a vacuum dryer set at 60°C to obtain the core layer-forming polymer. The weight-average molecular weight of the resulting polymer measured by GPC was 100,000.

[0122] (Preparation of Resin Composition for Forming Core Layer) 10 g of the purified core layer-forming polymer was weighed into a 100 mL glass container, and 30 g of toluene, 2.4 g of an oxetane compound (manufactured by Toagosei Co., Ltd., product name: OXT-213), 0.8 g of an epoxy compound having an alicyclic structure (manufactured by Daicel Corporation, product name: CELLOXIDE 2021P), 0.06 g of a photocationic polymerization initiator (manufactured by San-Apro Co., Ltd., product name: CPI-310B), and 0.1 g of an antioxidant (manufactured by BASF, product name: Irganox1076) were added thereto and dissolved uniformly. The mixture was then filtered through a 0.2 μm PTFE filter to obtain a core layer-forming resin composition.

[0123] (Preparation of dry film for core layer formation) The obtained core layer-forming resin composition was applied to a release-treated PET film using an applicator so that the film thickness after drying would be 40 μm. After coating, the film was placed in a dryer at 45°C for 5 minutes to completely remove the solvent, forming a coating. Finally, an OPP cover film was attached to the surface of the resin layer formed by the resin composition, thereby producing a dry film for forming a core layer.

[0124] (Preparation of dry film for forming second cladding layer) (Preparation of Resin Composition for Forming Second Clad Layer) <Examples 1 to 7> 8.0 g of a resin (A-1) having a norbornene structure, 2.0 g of JER_YX8034 (B-1), 0.03 g of BYK-333 (D-1), and 0.5 g of Curesol C11z (an imidazole compound manufactured by Shikoku Kasei Co., Ltd.) were weighed out, and 30 g of toluene was added to completely dissolve the mixture. The mixture was then filtered through a 0.2 μm PTFE filter to obtain a resin composition for forming a second clad layer used in Examples 1 to 7. <Comparative Examples 1 to 3> 10.0 g of a resin (A-1) having a norbornene structure and 0.3 g of Curesol C11z (an imidazole compound manufactured by Shikoku Kasei Corporation) were weighed out, and 30 g of toluene was added to completely dissolve the mixture. The mixture was then filtered through a 0.2 μm PTFE filter to obtain a resin composition for forming a second clad layer used in Comparative Examples 1 to 3. (Preparation of dry film for forming second cladding layer) The obtained resin composition for forming the second cladding layer was applied as a varnish using an applicator onto a 25 μm thick polyimide substrate so that the dried thickness would be 10 μm, and then dried at 100°C for 10 minutes.Finally, an OPP cover film was attached to the surface of the resin layer formed by the resin composition to create a film, and a dry film for forming the second cladding layer was obtained.

[0125] (Fabrication of photoelectric composite substrate) A double-sided copper-clad laminate measuring 80 mm wide, 120 mm long, and 50 μm thick, with two 100 μm diameter through-holes spaced 4 cm apart, was placed on a stainless steel plate. After peeling off the OPP cover film from the film for forming the first clad layer, the film was laminated using a vacuum laminator (manufactured by Nikko Materials Co., Ltd., model CVP-600) at a temperature of 140°C, a pressure of 5.0 MPa, and a time of 120 seconds so that the resin layer for forming the clad layer of the film for forming the first clad layer came into contact with the double-sided copper-clad laminate. The entire film for forming the first clad layer was then exposed to 1000 mJ / cm2 of light from a high-pressure mercury lamp. 2 The exposure was carried out under the conditions of (a) to (c) to obtain Laminate A having a layer structure of "double-sided copper-clad laminate / first clad layer / PET substrate." Here, the PET substrate is a PET substrate derived from the film for forming the first clad layer.

[0126] Next, the PET substrate of laminate A was peeled off, and the OPP cover film of the dry film for core layer formation was peeled off. The laminate was then laminated using a vacuum laminator (Nikko Materials Co., Ltd., CVP-300) at 60°C, pressure of 0.5 MPa, and time of 30 seconds, so that the first clad layer of laminate A and the core layer of the dry film for core layer formation were in contact. Next, a direct imaging exposure machine (SCREEN Co., Ltd., LI-9000) was used to create 20 lines and spaces 9 cm long, each 10 μm in exposed area and 50 μm in unexposed area, to form a waveguide circuit passing through the two through holes in the double-sided copper-clad laminate. The PET substrate from the dry film for core layer formation was then peeled off, and the laminate was heated in an atmospheric oven at 120°C for 1 hour to obtain laminate B, which had a layer structure of "double-sided copper-clad laminate / first clad layer / core layer."

[0127] Next, the OPP cover film of the dry film for forming the second cladding layer was peeled off, and then the core layer in laminate B and the resin layer (a resin layer consisting of a resin composition for forming a cladding layer) in the dry film for forming the second cladding layer were laminated using a vacuum laminator (manufactured by Nikko Materials Co., Ltd., device name: CVP-300) under conditions of temperature: 140°C, pressure: 0.5 MPa, and time: 120 seconds so that they were in contact, and then heated in an atmospheric oven at 160°C for 2 hours. Next, an excimer laser (wavelength 193 nm, manufactured by OPTEC, product name: ProMaster) was used to irradiate the optical waveguide above the through-hole from the polyimide substrate side, with a laser intensity of 7 mJ, a laser oscillation frequency of 250 Hz, an opening in the stainless steel mask for cutting the laser light of 1 mm x 1 mm, a movement speed of the processing table of 45 μm / s, and a movement distance of the processing table of 150 μm, and mirror processing was performed so that the angle was approximately 45 degrees, thereby obtaining the optoelectronic composite substrates of Examples 1 to 7 and Comparative Examples 1 to 3. The layer structure of the optoelectronic composite substrate was "double-sided copper-clad laminate / first clad layer / core layer / second clad layer / polyimide substrate."

[0128] [evaluation] The evaluation methods for the examples and comparative examples are described below.

[0129] <Coatability evaluation> The appearance of the films of Examples 1 to 7 and Comparative Examples 1 to 3 was observed, and samples with no appearance abnormalities such as those of standard B were rated as A, and samples with appearance abnormalities (uneven coating, cloudiness, repelling, cracks, etc.) were rated as B.

[0130] <Refractive index> The OPP cover film was peeled off from the films of Examples 1 to 7 and Comparative Examples 1 to 3, and the refractive index was measured at 23° C. and 589 nm using an Abbe refractometer (manufactured by Atago Co., Ltd., product name: NAR-1T SOLID).

[0131] <Light transmittance for a wavelength of 850 nm> For the films of Examples 1 to 7 and Comparative Examples 1 to 3, the OPP cover film was peeled off, and the resin layer formed from the resin composition was laminated onto a glass slide at a temperature of 100°C, a pressure of 0.5 MPa, and a time of 2 minutes, with the resin layer facing the glass slide. The substrate film was then peeled off to obtain a sample for transmittance measurement (a glass slide with the resin composition). Subsequently, a 100% calibration was performed using a UV-visible spectrophotometer (manufactured by JASCO Corporation, product name: V-670) with glass slides inserted into both the background slot and the sample slot. The glass slide in the measurement slot was replaced with the transmittance measurement sample, and the light transmittance [%] at a wavelength of 850 nm was measured in transmittance measurement mode.

[0132] <Embeddability evaluation> For the optoelectronic composite substrates of Examples 1 to 7 and Comparative Examples 1 to 3, the through holes of the substrates were observed under a microscope, and samples that were filled without voids were rated as A, samples that were insufficiently filled as B, and samples that had poor filling such as voids or bleeding after filling were rated as C.

[0133] <Evaluation of optical loss after reflow> The optoelectronic composite substrates of Examples 1 to 7 and Comparative Examples 1 to 3 were treated three times in an N2 reflow machine at a maximum temperature of 250°C. Subsequently, 850 nm light was incident through the first through-hole using an incident fiber, and the light emerging from the opposite through-hole was detected using a receiving fiber to measure the optical propagation loss. The distance between the through-holes was 4 cm. From the results obtained, the optical loss after reflow was evaluated by classifying samples with a propagation loss of less than 1 dB as A, samples with a propagation loss of 1 dB to 3 dB as B, and samples with a propagation loss of more than 3 dB as C.

[0134] <Mirror angle change rate evaluation> For the optoelectronic composite substrates of Examples 1 to 7 and Comparative Examples 1 to 3, the mirrors on the optical waveguides were measured using a laser microscope, and the post-processing mirror angle (angle A) was calculated. Next, the mirror-processed optical waveguide samples were treated three times in an N2 reflow device at a maximum temperature of 250°C, and the mirror angle (angle B) was measured again. The rate of change in the mirror angle before and after reflow was calculated using the following formula, and samples with a rate of change of less than 1% were rated as A, samples with a rate of change of 1 to 3% as B, and samples with a rate of change of more than 3% as C. Mirror angle change rate [%] = [(angle A - angle B) / angle A] x 100

[0135] The evaluation results for each example and each comparative example are shown in Table 1.

[0136] [Table 1]

[0137] It can be seen from Table 1 that the resin compositions of the examples were good in both embeddability and mirror angle change rate evaluations. That is, the resin composition of this embodiment can provide a resin composition that can improve embeddability and suppress thermal deformation of an optical waveguide. [Explanation of symbols]

[0138] 20 First cladding layer 30 Core Layer 40 Second cladding layer 50 Mirror on the light-emitting element side 60 Mirror on the light receiving element side 100 optical waveguide 110 Substrate 120 Light-emitting element 130 Photodetector 140a, 140b vias 200 Optical and electrical composite substrate

Claims

1. A resin composition that can be used for an optical waveguide clad, The composition comprises a resin (A) having a norbornene structure and a compound (B) having a cyclic ether structure, The resin composition, wherein the compound (B) having a cyclic ether structure contains two or more cyclic ether structures in the molecule and has a functional group equivalent of 400 g / mol or less.

2. The resin composition according to claim 1, wherein the compound (B) having a cyclic ether structure includes at least one selected from the group consisting of epoxy compounds and oxetane compounds.

3. The resin composition according to claim 1 or 2, wherein the compound (B) having a cyclic ether structure contains an alicyclic structure in the molecule.

4. The resin composition according to claim 1 or 2, wherein the compound (B) having a cyclic ether structure does not contain a siloxane bond in the main chain.

5. The resin composition according to claim 1 or 2, wherein the compound (B) having a cyclic ether structure does not contain a trimethoxysilane skeleton.

6. The resin composition according to claim 1 or 2, wherein the compound (B) having a cyclic ether structure does not contain a silicon atom.

7. The resin composition according to claim 1 or 2, wherein the compound (B) having a cyclic ether structure is liquid at 23°C.

8. The resin composition according to claim 1 or 2, wherein the refractive index of the compound (B) having a cyclic ether structure is 1.43 or more and 1.55 or less.

9. 3. The resin composition according to claim 1, wherein the content of the compound (B) having a cyclic ether structure in the resin composition is 5% by mass or more and 80% by mass or less, when the total content of non-volatile components in the resin composition is 100% by mass.

10. The resin composition according to claim 1 or 2, wherein the resin (A) having a norbornene structure contains a structural unit represented by the following formula (1): 【Chemical 1】 (In the formula (1), R represents a hydrogen atom, a hydroxyl group, or an organic group having 1 to 30 carbon atoms.)

11. 11. The resin composition according to claim 10, wherein R in the formula (1) is any one selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 10 carbon atoms.

12. The resin composition according to claim 1 or 2, wherein the resin (A) having a norbornene structure contains a structural unit represented by the following formula (2): 【Chemistry 2】 (In the formula (2), X represents a divalent organic group having 1 to 30 carbon atoms, and Y represents a group having a cyclic ether structure.)

13. The resin composition according to claim 12, wherein the structural unit represented by the formula (2) includes a structural unit represented by the following formula (2-1): 【Chemistry 3】 (In the formula (2-1), a represents an integer of 0 or more and 3 or less, and b represents an integer of 1 or more and 3 or less.)

14. The resin composition according to claim 1 or 2, wherein the resin (A) having a norbornene structure has a refractive index of 1.45 or more and 1.55 or less.

15. 3. The resin composition according to claim 1, wherein the content of the resin (A) having a norbornene structure in the resin composition is 20% by mass or more and 95% by mass or less, when the total content of non-volatile components in the resin composition is 100% by mass.

16. The resin composition according to claim 1 or 2, further comprising a curing agent (C).

17. The resin composition according to claim 16, wherein the curing agent (C) comprises a cationic polymerization initiator.

18. The resin composition according to claim 17, wherein the cationic polymerization initiator comprises a photocationic polymerization initiator.

19. The resin composition according to claim 1 or 2, having a refractive index of 1.47 or more and 1.55 or less.

20. A resin film made of the resin composition according to claim 1 or 2, The resin film has a light transmittance of 85% or more for a wavelength of 850 nm.

21. The resin film according to claim 20, having a thickness of 1 μm or more and 150 μm or less.

22. A film comprising a resin layer formed from the resin composition according to claim 1 or 2.

23. Further, a base film is provided, The film according to claim 22 , comprising the resin layer on the substrate film.

24. The film according to claim 23, wherein the resin constituting the base film comprises at least one selected from the group consisting of polyimide and polyethylene terephthalate.

25. 23. The film of claim 22, wherein the film is a dry film.

26. a first film and a second film; 23. A film set, wherein at least one of the first film and the second film is the film of claim 22.

27. An optical waveguide in which a first clad layer, a core layer, and a second clad layer are laminated in this order, An optical waveguide, wherein at least one of the first clad layer and the second clad layer comprises the resin composition according to claim 1 or 2.

28. A substrate; An optical / electrical composite substrate comprising: the optical waveguide according to claim 27 provided on the substrate.

29. An electronic component comprising the optical-electrical composite substrate according to claim 28.

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