Composition for core, composition set, optical waveguide, and electronic device

Abstract

To provide a composition for a core from which an optical waveguide having improved thermal reliability can be obtained.SOLUTION: A composition for a core, which is usable in a core of an optical waveguide, contains a polyimide resin (A), and polyfunctional (meth)acrylate (B).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a core composition, a composition set, an optical waveguide, and an electronic device.

Background Art

[0002] In recent years, in information and communication devices, there has been a demand for components that can achieve more advanced information communication such as increased information capacity and higher information communication speed. As one such component, optical waveguides have been studied.

[0003] As a technology for optical waveguides, for example, the technology described in Patent Document 1 can be mentioned.

[0004] Patent Document 1 describes an optical waveguide formed by laminating a core layer made of a polymer and a cladding layer made of a polymer on a substrate, wherein the core layer is sandwiched from a direction parallel to the surface of the substrate by a cladding layer having a refractive index smaller than that of the cladding layer sandwiching the core layer from a direction perpendicular to the surface of the substrate. According to the optical waveguide of Patent Document 1, it is described that an optical waveguide with less polarization dependence can be realized even when using a polymer with high birefringence such as polyimide.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention provides a core composition capable of obtaining an optical waveguide with improved thermal reliability.

Means for Solving the Problems

[0007] According to the present invention, there are provided a core composition, a composition set, an optical waveguide, and an electronic device as described below.

[0008] [1] A core composition that can be used for the core of an optical waveguide, including a polyimide resin (A) and a polyfunctional (meth)acrylate (B), the core composition. [2] The core composition according to [1] above, wherein the polyimide resin (A) contains a fluorine atom in the molecule. [3] The core composition according to [1] or [2] above, wherein the polyimide resin (A) contains an imide ring structure in the molecule. [4] The core composition according to any one of [1] to [3] above, wherein the polyimide resin (A) contains a structural unit represented by the following general formula (a).

Chemical formula

[10] The core composition according to any one of [1] to [9], further comprising a photosensitizer (C).

[11] The core composition according to any one of [1] to

[10] , further comprising a thermal radical generator (D).

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

[11] , further comprising an epoxy compound (E).

[13] The core composition according to

[12] , further comprising a curing catalyst (F) for the epoxy compound (E).

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

[13] , further comprising a silane coupling agent (G).

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

[14] , further comprising a surfactant (H).

[16] The core composition according to any one of [1] to

[15] , further comprising an organic solvent (I).

[17] The core composition according to any one of [1] to

[16] , which is in the form of a varnish.

[18] The core composition according to any one of [1] to

[17] , having a refractive index at 30 °C and a wavelength of 1310 nm of 1.500 or more and 1.560 or less.

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

[18] , having an absorbance at 22 °C and a wavelength of 1310 nm of 0.020 or more and 0.050 or less.

[20] The core composition according to any one of [1] to

[19] , and a clad composition that can be used for the clad of an optical waveguide, comprising a composition set.

[21] The composition set according to the above

[20] , wherein the composition for the clad contains a cyclic olefin resin and a polyfunctional (meth) acrylate.

[22] The composition set according to the above

[20] , wherein the composition for the clad contains a cyclic olefin resin and a phenol compound.

[23] An optical waveguide comprising a core made of the core composition according to any one of the above [1] to

[19] .

[24] Comprising a silicon photonics device, The silicon photonics device is an electronic device comprising the optical waveguide according to the above

[23] .

Advantages of the Invention

[0009] According to the present invention, it is possible to provide a core composition capable of obtaining an optical waveguide with improved thermal reliability.

Brief Description of the Drawings

[0010]

Figure 1

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the drawings are schematic diagrams and do not match the actual dimensional ratios. The numerical range "A to B" represents A or more and B or less unless otherwise specified. (Meth) acrylate is a concept including both acrylate and methacrylate. Also, the (meth) acryloyl group is a concept including both the acryloyl group and the methacryloyl group.

[0012] An optical waveguide may be formed, for example, on a chip (e.g., a silicon chip or the like). Since the chip may generate heat, the optical waveguide formed on the chip may be required to have thermal reliability. Here, in this specification, a high thermal reliability of the optical waveguide means that when an environmental test (e.g., conditions of 125°C for 1000 hours) is performed on the optical waveguide, the difference between the propagation loss of the optical waveguide after the environmental test and the propagation loss of the optical waveguide before the environmental test is small.

[0013] The present invention provides a core composition capable of obtaining an optical waveguide with improved thermal reliability.

[0014] [Core Composition] The core composition of the present embodiment is a core composition that can be used for the core of an optical waveguide, and includes a polyimide resin (A) and a polyfunctional (meth)acrylate (B).

[0015] The refractive index of the core composition of the present embodiment at 30°C and a wavelength of 1310 nm is preferably 1.500 or more, more preferably 1.510 or more, and even more preferably 1.520 or more, from the viewpoint of further improving the optical propagation efficiency of the optical waveguide. The upper limit is not particularly limited, and may be, for example, 1.560 or less, or may be 1.540 or less. Here, the refractive index of the core composition at 30°C and a wavelength of 1310 nm means the value of the refractive index calculated by the method described in the examples.

[0016] The absorbance of the core composition of the present embodiment at 22°C and a wavelength of 1310 nm is preferably 0.050 or less, more preferably 0.045 or less, and even more preferably 0.040 or less, from the viewpoint of further improving the optical propagation efficiency of the optical waveguide. The lower limit is not particularly limited, and may be, for example, 0.020 or more, or may be 0.025 or more. Here, the absorbance of the core composition at 22°C and a wavelength of 1310 nm means the value of the absorbance calculated by the method described in the examples.

[0017] The shape of the core composition of the present embodiment is not particularly limited, and may be, for example, a varnish shape, a film shape, a film shape, a sheet shape, etc., but preferably a varnish shape.

[0018] Hereinafter, each constituent of the core composition of the present embodiment will be described.

[0019] <Polyimide resin (A)> The core composition of the present embodiment contains a polyimide resin (A).

[0020] From the viewpoint of further suppressing the shrinkage of the composition due to curing (heating), the polyimide resin (A) preferably contains an imide ring structure in the molecule.

[0021] The imidization rate of the polyimide resin (A) is preferably 90% or more, more preferably 93% or more, still more preferably 95% or more, still more preferably 97% or more, and still more preferably 98% or more. The imidization rate of the polyimide resin (A) means the imidization rate represented by {IM / (IM + AM)}×100 (%) when the number of moles of imide groups contained in the polyimide resin (A) is IM and the number of moles of amide groups contained in the polyimide resin (A) is AM. The imidization rate can be determined, for example, from the areas of the peaks corresponding to amide groups and the peaks corresponding to imide groups in the NMR spectrum. As another example, the imidization rate can be determined from the areas of the peaks corresponding to amide groups and the peaks corresponding to imide groups in the infrared absorption spectrum.

[0022] The polyimide resin (A) preferably contains fluorine atoms in the molecule. Since the polyimide resin (A) contains fluorine atoms in the molecule, the solubility in an organic solvent is further improved, and it becomes easier to obtain a varnish-like resin composition. The amount (mass ratio) of fluorine atoms in the polyimide containing fluorine atoms is preferably 1% by mass or more and 30% by mass or less, more preferably 3% by mass or more and 28% by mass or less, and still more preferably 5% by mass or more and 25% by mass or less from the viewpoint of further improving the solubility in an organic solvent.

[0023] The polyimide resin (A) preferably contains a structural unit represented by the following general formula (a).

[0024]

Chemical formula

[0025] In the general formula (a), X is a divalent organic group, and Y is a tetravalent organic group.

[0026] In the general formula (a), from the viewpoint of further improving the solubility in an organic solvent, preferably at least one of X and Y is a fluorine atom-containing group, and more preferably both X and Y are fluorine atom-containing groups. In the general formula (a), from the viewpoint of further improving the heat resistance of the cured product composed of the composition, at least one of X and Y preferably contains an aromatic ring structure, and more preferably contains a benzene ring structure. In the general formula (a), at least one of X and Y preferably contains a structure in which 2 to 6 benzene rings are bonded via a single bond or a divalent linking group. Here, examples of the divalent linking group include at least one selected from the group consisting of an alkylene group, a fluorinated alkylene group, and an ether group. The alkylene group and the fluorinated alkylene group may be linear or branched. In the general formula (a), the number of carbon atoms of X is, for example, 6 to 30. In the general formula (a), the number of carbon atoms of Y is, for example, 6 to 20. In the general formula (a), the two imide rings are preferably 5-membered rings, respectively.

[0027] The polyimide resin (A) more preferably contains a structural unit represented by the following general formula (aa).

[0028] [Chem.]

[0029] In general formula (aa), Y' represents a single bond or an alkylene group, and X has the same meaning as X in general formula (a).

[0030] In general formula (aa), from the viewpoint of further improving the solubility in an organic solvent, preferably at least one of X and Y' is a fluorine-containing group, and more preferably both X and Y' are fluorine atom-containing groups. In general formula (aa), the alkylene group of Y' may be linear or branched. Part or all of the hydrogen atoms of the alkylene group of Y' are preferably substituted with fluorine atoms. The number of carbon atoms of the alkylene group of Y' is preferably 1 to 6, more preferably 1 to 4, and still more preferably 1 to 3.

[0031] The polyimide resin (A) may contain an azole structure in the molecule. The polyimide resin (A) may have an azole structure in the side chain of the polyimide resin or may have an azole structure at the terminal of the polyimide resin. Preferably, it has an azole structure at the terminal of the polyimide, and more preferably, it has an azole structure only at one terminal of the polyimide.

[0032] The azole structure preferably contains at least one selected from the group consisting of a triazole structure and a tetrazole structure, and more preferably contains a triazole structure.

[0033] From the viewpoint of further improving the heat resistance of the cured product composed of the composition, the weight average molecular weight (Mw) of the polyimide resin (A) is preferably 5,000 or more, more preferably 7,000 or more, and still more preferably 10,000 or more. From the viewpoint of further improving the solubility in an organic solvent, it is preferably 100,000 or less, more preferably 75,000 or less, and still more preferably 50,000 or less. The weight-average molecular weight of the polyimide resin can be determined by gel permeation chromatography (GPC) using polystyrene as a standard substance.

[0034] When the total solid content in the core composition of this embodiment is 100% by mass, the content of the polyimide resin (A) in the core composition is preferably 20% by mass or more, more preferably 25% by mass or more, still more preferably 30% by mass or more, and even more preferably 35% by mass or more, and is preferably 70% by mass or less, more preferably 65% by mass or less, and still more preferably 60% by mass or less. Here, in this specification, the total solid content in the composition means all components that remain as solid components in the cured product composed of the composition.

[0035] The polyimide resin (A) can be obtained, for example, by (i) first reacting (condensing and polymerizing) a diamine and an acid dianhydride to synthesize a polyamide, and (ii) then imidizing (ring-closing reacting) the polyamide. Specific reaction conditions can be, for example, known conditions. In addition, a polyimide resin containing an azole structure in the molecule can be obtained, for example, by reacting a compound containing an azole structure together with a diamine and an acid dianhydride in the above step (i).

[0036] As the diamine raw material for synthesizing the polyimide resin (A), for example, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 3,4'-diaminodiphenyl ether (3,4'-ODA), 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl (TFMB), 3,3',5,5'-tetramethylbenzidine, 2,3,5,6-tetramethyl-1,4-phenylenediamine, 3,3'-diaminodiphenyl sulfone, 3,3'-dimethylbenzidine, 3,3'-bis(trifluoromethyl)benzidine, 2,2'-bis(p-aminophenyl)hexafluoropropane, bis(trifluoromethoxy)benzidine (TFMOB), 2,2'-bis(pentafluoroethoxy)benzidine (TFEOB), 2,2'-trifluoromethyl-4,4'-oxydianiline (OBABTF), 2-phenyl-2-trifluoromethyl-bis(p-aminophenyl)methane, 2-phenyl-2-trifluoromethyl-bis(m-aminophenyl)methane, 2,2'-bis(2-heptafluoroisopropoxy-tetrafluoroethoxy)benzidine (DFPOB), 2,2-bis(m-aminophenyl)hexafluoropropane (6-FmDA), 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane, 3,6-bis(trifluoromethyl)-1,4-diaminobenzene (2TFMPDA), 1-(3,5-diaminophenyl)-2,2-bis(trifluoromethyl)-3,3,4,4,5,5,5-heptafluoropentane, 3,5-diaminobenzotrifluoride (3,5-DABTF), 3,5-diamino-5-(pentafluoroethyl)benzene, 3,5-diamino-5-(heptafluoropropyl)benzene, 2,2'-dimethylbenzidine (DMBZ), 2,2',6,6'-tetramethylbenzidine (TMBZ), 3,6-diamino-9,9-bis(trifluoromethyl)xanthene (6FCDAM), 3,6-diamino-9-trifluoromethyl-9-phenylxanthene (3FCDAM), 3,6-diamino-9,9-diphenylxanthene, etc. can be mentioned. The diamine may be used alone or in combination of two or more kinds.

[0037] Examples of the acid dianhydride as a raw material for synthesizing the polyimide resin (A) include 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride, 4,4'-oxydiphthalic dianhydride, pyromellitic dianhydride (PMDA), diphenyl ether-3,3',4,4'-tetracarboxylic dianhydride (ODPA), benzophenone-3,3',4,4'-tetracarboxylic dianhydride (BTDA), biphenyl-3,3',4,4'-tetracarboxylic dianhydride (BPDA), diphenyl sulfone-3,3',4,4'-tetracarboxylic dianhydride (DSDA), diphenylmethane-3,3',4,4'-tetracarboxylic dianhydride, 2,2-bis(3,4-phthalic anhydride)propane, 2,2-bis(3,4-phthalic anhydride)-1,1,1,3,3,3-hexafluoropropane (6FDA), and the like. The acid dianhydride may be used alone or in combination of two or more kinds.

[0038] The polyimide resin (A) may be a single polyimide resin or may contain two or more polyimide resins.

[0039] <Polyfunctional (meth)acrylate (B)> The core composition of this embodiment contains polyfunctional (meth)acrylate (B). In this specification, the polyfunctional (meth)acrylate means a (meth)acrylate compound having two or more (meth)acryloyl groups in one molecule.

[0040] The polyfunctional (meth)acrylate (B) preferably contains a (meth)acrylate compound (B1) having 5 or more functional groups. The number of functional groups of the (meth)acrylate compound (B1) is, for example, 11 or less.

[0041] The polyfunctional (meth)acrylate (B) preferably contains a (meth)acrylate compound (B2) having 2 or more and 4 or less functional groups.

[0042] The polyfunctional (meth)acrylate (B) preferably contains a (meth)acrylate compound (B1) having 5 or more functional groups and a (meth)acrylate compound (B2) having 2 to 4 functional groups. The inventors of the present invention believe that in the core composition of the present embodiment, a "complex structure formed by the entanglement of polyimide (A) and polyfunctional (meth)acrylate (B)" is formed during curing (polymerization), and this complex structure contributes to the improvement of the performance balance of heat resistance and mechanical properties. When the core composition contains a (meth)acrylate compound (B1) having 5 or more functional groups and a (meth)acrylate compound (B2) having 2 to 4 functional groups, a more complex complex structure can be formed during curing (polymerization), so that the performance balance of heat resistance and mechanical properties can be further improved.

[0043] When the total of the (meth)acrylate compound (B1) having 5 or more functional groups and the (meth)acrylate compound (B2) having 2 to 4 functional groups in the core composition of the present embodiment is 100 parts by mass, the content of the (meth)acrylate compound (B2) having 2 to 4 functional groups is preferably 1 to 50 parts by mass, more preferably 5 to 40 parts by mass, and still more preferably 8 to 25 parts by mass.

[0044] Specific examples of the polyfunctional (meth)acrylate (B) include, for example, polyol polyacrylates such as ethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy acrylates such as di(meth)acrylate of bisphenol A diglycidyl ether and di(meth)acrylate of hexanediol diglycidyl ether, and urethane (meth)acrylate obtained by the reaction of a polyisocyanate and a hydroxyl group-containing (meth)acrylate such as hydroxyethyl (meth)acrylate.

[0045] Examples of commercially available products of the polyfunctional (meth)acrylate (B) include, for example, Aronix M-400, Aronix M-460, Aronix M-402, Aronix M-510, Aronix M-520 (manufactured by Toagosei Co., Ltd.), KAYARAD T-1420, KAYARAD DPHA, KAYARAD DPCA20, KAYARAD DPCA30, KAYARAD DPCA60, KAYARAD DPCA120 (manufactured by Nippon Kayaku Co., Ltd.), Viscoat #230, Viscoat #300, Viscoat #802, Viscoat #2500, Viscoat #1000, Viscoat #1080 (manufactured by Osaka Organic Chemical Industry Co., Ltd.), NK Ester A-BPE-10, NK Ester A-GLY-9E, NK Ester A-9550, NK Ester A-DPH (manufactured by Shin-Nakamura Chemical Co., Ltd.), and the like.

[0046] When the content of the polyfunctional (meth)acrylate (B) in the core composition of the present embodiment is based on 100 parts by mass of the polyimide resin (A) in the core composition, it is preferably 20 parts by mass or more and 150 parts by mass or less, more preferably 30 parts by mass or more and 130 parts by mass or less, and still more preferably 40 parts by mass or more and 110 parts by mass or less. When the content of the polyfunctional (meth)acrylate (B) is within the above numerical range, the "entangled structure of the polyimide (A) and the polyfunctional (meth)acrylate (B)" is sufficiently entangled, and the amount of extra components not involved in the entanglement is reduced, so that the balance of performance of heat resistance, mechanical properties, and other properties can be further improved.

[0047] The polyfunctional (meth)acrylate (B) may be one kind of polyfunctional (meth)acrylate or may contain two or more kinds of polyfunctional (meth)acrylates, but preferably contains two or more kinds of polyfunctional (meth)acrylates.

[0048] <Photosensitizer (C)> The core composition of the present embodiment preferably further contains a photosensitizer (C). The photosensitizer (C) is not particularly limited as long as it can generate active species by light and cure the photosensitive resin composition.

[0049] The photosensitizer (C) contains, for example, at least one selected from the group consisting of a photo radical generator and a photo cation generator, etc., and preferably contains a photo radical generator from the viewpoint of effectively polymerizing the polyfunctional (meth)acrylate (B). The photo radical generator contains, for example, at least one selected from the group consisting of an oxime ester compound, an alkylphenone compound, a benzophenone compound, a benzoin compound, a thioxanthone compound, a halomethylated triazine compound, a halomethylated oxadiazole compound, a biimidazole compound, a titanocene compound, a benzoic acid ester compound, and an acridine compound, etc., and preferably contains an oxime ester compound.

[0050] When the content of the polyfunctional (meth)acrylate (B) in the core composition of the present embodiment is 100 parts by mass, the content of the photosensitizer (C) in the core composition is preferably 1 part by mass or more and 30 parts by mass or less, and more preferably 5 parts by mass or more and 25 parts by mass or less.

[0051] The photosensitizer (C) may be one kind of photosensitizer or may contain two or more kinds of photosensitizers.

[0052] <Thermal radical generator (D)> From the viewpoint of further improving the performance balance of the heat resistance and chemical resistance of the cured product composed of the composition, the core composition of the present embodiment preferably further contains a thermal radical generator (D). When the core composition of the present embodiment contains a thermal radical generator (D), it is considered that the polymerization reaction of the polyfunctional (meth)acrylate (B) is more promoted.

[0053] The thermal radical generator (D) is not particularly limited, but preferably contains an organic peroxide.

[0054] When the content of the thermal radical generator (D) in the core composition of this embodiment is based on 100 parts by mass of the content of the polyfunctional (meth)acrylate (B) in the core composition, it is preferably 0.1 part by mass or more and 30 parts by mass or less, more preferably 1 part by mass or more and 20 parts by mass or less.

[0055] The thermal radical generator (D) may be a single type of thermal radical generator or may contain two or more types of thermal radical generators.

[0056] <Epoxy compound (E)> The core composition of this embodiment preferably further contains an epoxy compound (E). Since the core composition contains the epoxy compound (E), it is considered that chemical bonds are formed in the form of the reaction between the polyimide resin and the epoxy compound, the reaction between epoxy compounds, etc., so the mechanical properties (such as tensile elongation) of the cured product composed of the composition can be further improved.

[0057] The epoxy compound (E) is not particularly limited as long as it is a compound having an epoxy group in the molecule, and it may be a low molecular compound or an epoxy resin.

[0058] From the viewpoint of further improving the performance balance of the heat resistance and mechanical properties of the cured product composed of the composition, the epoxy compound (E) preferably contains 2 to 4 epoxy groups in one molecule, more preferably 2 to 3 epoxy groups in one molecule.

[0059] From the viewpoint of further improving the heat resistance of the cured product composed of the composition, the epoxy compound (E) preferably contains at least one selected from the group consisting of an aromatic ring structure and an alicyclic ring structure.

[0060] The epoxy compound (E) preferably contains a compound having at least one epoxy-containing group and (meth)acryloyl group in one molecule.

[0061] When the content of the polyimide resin (A) in the core composition of the present embodiment is 100 parts by mass, the content of the epoxy compound (E) in the core composition is preferably 0.5 parts by mass or more and 30 parts by mass or less, more preferably 1 part by mass or more and 20 parts by mass or less, and still more preferably 3 parts by mass or more and 15 parts by mass or less.

[0062] The epoxy compound (E) may be a single epoxy compound or may contain two or more epoxy compounds.

[0063] <Hardening catalyst (F)> The core composition of the present embodiment preferably further contains a hardening catalyst (F) for the epoxy compound (E). When the core composition contains the hardening catalyst (F), the reaction involving the epoxy compound (E) can proceed sufficiently, and for example, the tensile elongation rate of the cured product formed from the composition can be further improved.

[0064] The hardening catalyst (F) contains, for example, compounds known as hardening catalysts for epoxy compounds. The hardening catalyst (F) contains at least one selected from the group consisting of, for example, organic phosphines, diazabicycloalkenes and their derivatives, amine compounds, imidazole compounds, and tetra-substituted phosphonium salts, and preferably contains organic phosphines.

[0065] When the content of the epoxy compound (E) in the core composition of the present embodiment is 100 parts by mass, the content of the hardening catalyst (F) in the core composition is preferably 1 part by mass or more and 80 parts by mass or less, more preferably 3 parts by mass or more and 50 parts by mass or less, and still more preferably 5 parts by mass or more and 35 parts by mass or less.

[0066] The hardening catalyst (F) may be a single hardening catalyst or may contain two or more hardening catalysts.

[0067] <Silane coupling agent (G)> The core composition of the present embodiment preferably further contains a silane coupling agent (G). When the composition for the core contains the silane coupling agent (G), for example, the adhesion between the cured product made of the composition and the adjacent layer can be further improved.

[0068] The silane coupling agent (G) includes, for example, at least one selected from the group consisting of a silane coupling agent having a cyclic anhydride structure, an amino group-containing silane coupling agent, an epoxy group-containing silane coupling agent, a (meth)acryloyl group-containing silane coupling agent, a mercapto group-containing silane coupling agent, a vinyl group-containing silane coupling agent, a ureido group-containing silane coupling agent, and a sulfide group-containing silane coupling agent, etc., and preferably includes a silane coupling agent having a cyclic anhydride structure.

[0069] When the content of the polyimide resin (A) in the composition for the core is 100 parts by mass, the content of the silane coupling agent (G) in the composition for the core is preferably 0.1 part by mass or more and 20 parts by mass or less, more preferably 0.3 part by mass or more and 15 parts by mass or less, still more preferably 0.5 part by mass or more and 12 parts by mass or less, and even more preferably 1 part by mass or more and 10 parts by mass or less.

[0070] The silane coupling agent (G) may be a single silane coupling agent or may contain two or more silane coupling agents.

[0071] <Surfactant (H)> The composition for the core of the present embodiment preferably further contains a surfactant (H). <C When the composition for the core contains the surfactant (H), the coatability of the composition can be further improved, and furthermore, the flatness of the coating film made of the composition can be further improved.

[0072] The surfactant (H) includes at least one selected from the group consisting of, for example, a fluorine-based surfactant, a silicone-based surfactant, an alkyl-based surfactant, and an acrylic-based surfactant, etc., and preferably includes a fluorine-based surfactant.

[0073] From the viewpoint of further improving the coatability of the composition, the surfactant (H) preferably contains at least one selected from the group consisting of a fluorine atom and a silicon atom.

[0074] From the viewpoint of further improving the storage stability of the composition, the surfactant (H) preferably contains a nonionic surfactant.

[0075] When the content of the polyimide resin (A) in the core composition of the present embodiment is 100 parts by mass, the content of the surfactant (H) in the core composition is preferably 0.001 part by mass or more and 1 part by mass or less, more preferably 0.005 part by mass or more and 0.5 part by mass or less.

[0076] The surfactant (H) may be a single surfactant or may contain two or more surfactants.

[0077] <Organic solvent (I)> The core composition of the present embodiment preferably further contains an organic solvent (I). When the core composition contains the organic solvent (I), a varnish-like core composition can be obtained.

[0078] The organic solvent (I) contains, for example, at least one selected from the group consisting of acetone, methyl ethyl ketone, toluene, 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, butyl lactate, etc.

[0079] When the core composition contains the organic solvent (I), the concentration of the total solid content of the core composition is preferably 10% by mass or more and 50% by mass or less, more preferably 20% by mass or more and 45% by mass or less. When the concentration of the total solid content of the core composition is within the above range, each component can be sufficiently dissolved or dispersed, the coating property of the composition can be further improved, and furthermore, the viscosity of the composition can be appropriately controlled.

[0080] The organic solvent (I) may be a single organic solvent or may contain two or more organic solvents.

[0081] <Other components> The core composition of this embodiment may further contain other components. Examples of the other components include water, a polymerization inhibitor, a sensitizer, fillers such as silica, and a film-forming agent. The content of the other components is an appropriate amount.

[0082] When the total content of the polyimide resin (A) and the polyfunctional (meth)acrylate (B) in the core composition of this embodiment is 100% by mass of all the components in the core composition, it is preferably 10% by mass or more and 50% by mass or less, more preferably 15% by mass or more and 40% by mass or less, still more preferably 20% by mass or more and 30% by mass or less.

[0083] When the total content of the polyimide resin (A) and the polyfunctional (meth)acrylate (B) in the core composition of this embodiment is 100% by mass of the total solid content in the core composition, it is preferably 60% by mass or more and 95% by mass or less, more preferably 70% by mass or more and 90% by mass or less, still more preferably 75% by mass or more and 85% by mass or less.

[0084] The core composition of this embodiment can be obtained, for example, by mixing each component.

[0085] [Composition set] The composition set of this embodiment includes the core composition of this embodiment and a clad composition that can be used for the clad of an optical waveguide.

[0086] The clad composition of the present embodiment is not particularly limited as long as it is a composition that can be used for the clad of an optical waveguide. For example, it may be a resin composition containing a resin used for the clad of a known optical waveguide.

[0087] The shape of the clad composition of the present embodiment is not particularly limited. For example, it may be in the form of a varnish, film, sheet, etc., but preferably in the form of a varnish.

[0088] The clad composition of the present embodiment preferably contains a cyclic olefin resin and a polyfunctional (meth)acrylate. When the total content of the cyclic olefin resin and the polyfunctional (meth)acrylate in the clad composition of the present embodiment is based on 100% by mass of all components in the clad composition, it is preferably 10% by mass or more and 50% by mass or less, more preferably 15% by mass or more and 40% by mass or less. When the total content of the cyclic olefin resin and the polyfunctional (meth)acrylate in the clad composition of the present embodiment is based on 100% by mass of all solid components in the clad composition, it is preferably 60% by mass or more and 99% by mass or less, more preferably 80% by mass or more and 99% by mass or less, and still more preferably 90% by mass or more and 98% by mass or less.

[0089] Further, as another preferred embodiment of the clad composition of the present embodiment, it contains a cyclic olefin resin and a phenol compound. When the total content of the cyclic olefin resin and the phenol compound in the clad composition of the present embodiment is based on 100% by mass of all components in the clad composition, it is preferably 10% by mass or more and 50% by mass or less, more preferably 15% by mass or more and 40% by mass or less, and still more preferably 20% by mass or more and 30% by mass or less. When the total content of the cyclic olefin resin and the phenol compound in the clad composition of the present embodiment is based on 100% by mass of the total solid content in the clad composition, it is preferably 40% by mass or more and 90% by mass or less, more preferably 50% by mass or more and 80% by mass or less, and still more preferably 60% by mass or more and 70% by mass or less.

[0090] The cyclic olefin resin contained in the clad composition of the present embodiment is not particularly limited, but preferably contains a norbornene resin. The cyclic olefin resin of the present embodiment may contain structural units other than the structural units derived from cyclic olefins. For example, it contains at least one selected from the group consisting of structural units derived from maleimide and structural units derived from maleic anhydride.

[0091] As the polyfunctional (meth)acrylate contained in the clad composition of the present embodiment, for example, the same ones as the polyfunctional (meth)acrylate (B) contained in the core composition of the present embodiment can be used.

[0092] The phenol compound contained in the clad composition of the present embodiment is not particularly limited, but preferably contains a phenol compound having a substituent containing an aliphatic hydrocarbon group, and more preferably contains at least one selected from the group consisting of propyl 4-hydroxybenzoate, methyl 4-hydroxybenzoate, butyl 4-hydroxybenzoate, and hexyl 4-hydroxybenzoate.

[0093] The clad composition of the present embodiment may contain, for example, an organic solvent, a photopolymerization initiator, an adhesion aid, a surfactant, etc. The content of these components is an appropriate amount.

[0094] The clad composition of the present embodiment can be obtained, for example, by mixing each component.

[0095] [Optical waveguide] The optical waveguide of the present embodiment includes a core made of the core composition of the present embodiment.

[0096] Figure 1 is a cross-sectional view schematically showing an example of the structure of the optical waveguide of the present embodiment. An example of the optical waveguide of the present embodiment will be described with reference to FIG. 1. In FIG. 1, the optical waveguide 100 is formed on the wafer 50. The optical waveguide 100 includes an underclad 10, a core 20, and an overclad 30.

[0097] <Core> The core 20 is made of the core composition of the present embodiment. The core composition forming the core 20 may be a cured product, a semi-cured product, or an uncured product, but is preferably a cured product.

[0098] The thickness and line width of the core 20 are not particularly limited, but are preferably dimensions that satisfy the single-mode condition. The single-mode condition depends on the relative refractive index difference between the core and the cladding and the guided wavelength, but the thickness and line width of the core 20 are preferably 1 μm or more and 11 μm or less, more preferably 2 μm or more and 10 μm or less.

[0099] <Cladding> The underclad 10 and the overclad 30 will be described. Hereinafter, when simply referred to as "clad", unless otherwise specified, it means a concept including both the underclad 10 and the overclad 30.

[0100] The material constituting the cladding is not particularly limited, and for example, a material forming the cladding of a known optical waveguide can be used, which may be an organic material or an inorganic material.

[0101] The cladding may be composed of, for example, the cladding composition in the composition set of the present embodiment. The cladding composition forming the cladding may be a cured product, a semi-cured product, or an uncured product, but is preferably a cured product.

[0102] The cladding may be composed of, for example, SiO2.

[0103] The underclad 10 and the overclad 30 may be made of the same type of material or different types of materials.

[0104] The thickness of the underclad 10 is not particularly limited, but is preferably 1 μm or more and 25 μm or less, more preferably 3 μm or more and 20 μm or less, and still more preferably 5 μm or more and 15 μm or less. The thickness of the overclad 30 from the surface of the underclad 10 is not particularly limited, but is preferably 3 μm or more and 50 μm or less, more preferably 5 μm or more and 40 μm or less, and still more preferably 10 μm or more and 30 μm or less. The thickness of the overclad 30 from the surface of the core 20 is not particularly limited, but is preferably 1 μm or more and 25 μm or less, more preferably 3 μm or more and 20 μm or less, and still more preferably 5 μm or more and 15 μm or less.

[0105] The optical waveguide 100 may further include a configuration other than the underclad 10, the core 20, and the overclad 30.

[0106] The method for manufacturing the optical waveguide 100 is not particularly limited, and for example, includes the following steps (i) to (iii). (i) Apply a varnish-like clad composition on the wafer 50, dry it to form an underclad layer, and cure the obtained underclad layer to form the underclad 10. (ii) Apply a varnish-like core composition on the underclad 10, dry it to form a core layer, and cure the obtained core layer to form the core 20. (iii) Apply a varnish-like clad composition on the core 20, dry it to form an overclad layer, and cure the obtained overclad layer to form the overclad 30. The method for applying the varnish-like composition is not particularly limited, and for example, a spin coating method can be used.

[0107] [Electronic device] The electronic device of this embodiment includes the optical waveguide of this embodiment, preferably includes a silicon photonics device, and the silicon photonics device includes the optical waveguide of this embodiment. Here, silicon photonics is a technology for integrating elements such as optical waveguides, optical switches, optical modulators, and light receivers on a silicon wafer, and a silicon photonics device means a device that utilizes silicon photonics technology.

[0108] A silicon photonics device is, for example, as shown in FIG. 1, a device in which an optical waveguide 100 is formed on a wafer 50. At this time, the wafer 50 is a silicon wafer. The silicon photonics device may further include, for example, a Si wire waveguide or the like.

[0109] Examples of the electronic device of this embodiment include electronic devices such as mobile phones, game machines, router devices, WDM devices, personal computers, televisions, and home servers.

[0110] As described above, the embodiments of the present invention have been described, but these are examples of the present invention, and various configurations other than those described above can also be adopted. In addition, the present invention is not limited to the foregoing embodiments, and modifications, improvements, etc. within the scope that can achieve the object of the present invention are included in the present invention.

Example

[0111] Hereinafter, this embodiment will be described in detail based on examples and comparative examples. Note that this embodiment is not limited to the descriptions of these examples.

[0112] [Raw materials] <Synthesis of polyimide resin (A-1)> Into a 3 L separable flask made of glass equipped with a stirring device and a stirring blade, 64.1 g (0.20 mol) of 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB), 97.7 g (0.22 mol) of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) and 500 g of dimethylacetamide (DMAc) were charged and stirred to dissolve TFMB and 6FDA in DMAc. Further, under a nitrogen stream, stirring was continued at room temperature for 12 hours to carry out a polymerization reaction to obtain a polyamic acid solution.

[0113] After adding 16 g of pyridine to the obtained polyamic acid solution, 82 g of acetic anhydride was added dropwise at room temperature. Then, the liquid temperature was further maintained at 20 to 100 °C and stirring was continued for 24 hours to carry out an imidization reaction to obtain a polyimide solution.

[0114] The obtained polyimide solution was poured into 1,000 g of methanol while stirring in a container with a volume of 5 L to precipitate a polyimide resin. Then, the solid polyimide resin was filtered off using a suction filtration device and further washed with 1,000 g of methanol. And it was dried at 100 °C for 24 hours using a vacuum dryer and further dried at 200 °C for 3 hours. Thus, a polyimide resin (A-1) which is a polyimide powder having an acid anhydride group at the terminal was obtained. The weight average molecular weight (Mw) of the polyimide resin (A-1) by GPC measurement was 25,000. Also, the polyimide resin (A-1) was 1 subjected to 1H-NMR measurement, and the imidization rate was calculated from the quantitative value of the amide peak with respect to the peak of the aromatic ring of the polyimide. The imidization rate was 99% or more.

[0115] <Synthesis of polyimide resin (A-2)> Into a 5 L separable flask equipped with a stirrer and a cooling tube, 256.2 g (0.80 mol) of 2,2'-bis(trifluoromethyl)benzidine, 355.4 g (0.80 mol) of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 8.4 g (0.1 mol) of 3-amino-1,2,4-triazole as a triazole compound, and 1591 g of γ-butyrolactone were added. Then, it was stirred at room temperature for 3 hours under a nitrogen atmosphere. Thereafter, the temperature of the reaction solution was raised to 80 °C in an oil bath and stirred for 6 hours to carry out a polymerization reaction. Subsequently, the temperature of the reaction solution was raised to 180 °C and reacted for 3 hours to imidize the resin. Thereafter, it was cooled to room temperature to prepare a polyimide resin solution. Subsequently, while stirring the reaction solution at room temperature, methanol was added dropwise to precipitate a resin solid. The obtained solid was roughly filtered, and then further washed with methanol to obtain a white solid of polyimide. The obtained white solid was vacuum dried at 200 °C to obtain a polyimide resin (A-2) having a triazole skeleton at the terminal. The weight average molecular weight (Mw) of the polyimide resin (A-2) by GPC measurement was 76,000.

[0116] The details of the raw materials of each component in Table 1 are as follows.

[0117] <Polyimide resin (A)> (A-1) The polyimide resin synthesized above (A-2) The polyimide resin synthesized above

[0118] <Polyfunctional (meth)acrylate (B)> (B-1) Biscoat #802 (manufactured by Osaka Organic Chemical Industry Co., Ltd., a mixture of compounds having 5 to 10 acryloyl groups) (B-2) NK Ester A-9550 (manufactured by Shin-Nakamura Chemical Co., Ltd., a mixture of compounds having 5 to 6 acryloyl groups) (B-3) Biscoat #300 (manufactured by Osaka Organic Chemical Industry Co., Ltd., a mixture of compounds having 3 to 4 acryloyl groups) (B-4) Biscoat #230 (manufactured by Osaka Organic Chemical Industry Co., Ltd., a compound having 2 acryloyl groups) (B-5) NK Ester A-DPH (manufactured by Shin-Nakamura Chemical Co., Ltd., a compound having 5 to 6 acryloyl groups)

[0119] <Photosensitizer (C)> (C-1) Irugacure OXE01 (manufactured by BASF, an oxime ester type photo radical generator)

[0120] <Thermal Radical Generator (D)> (D-1) Perkadox BC (manufactured by Kayaku Nucreon Co., Ltd., an organic peroxide, cumyl peroxide)

[0121] <Epoxy Compound (E)> (E-1) TECHMORE VG3101L (manufactured by Printec Co., Ltd.) (E-2) Celoxide 2021P (manufactured by Daicel Corporation) (E-3) 4HBAGE (manufactured by Mitsubishi Chemical Corporation, 4-hydroxybutyl acrylate glycidyl ether) (E-4) Cyclomer M100 (manufactured by Daicel Corporation, 3,4-epoxycyclohexylmethyl methacrylate)

[0122] <Curing Catalyst (F)> (F-1) Tetraphenylphosphonium · 4,4'-sulfonyldiphenolate The synthesis method of the above curing catalyst (F-1) is as follows. Into a separable flask equipped with a stirrer, 37.5 g (0.15 mol) of 4,4'-bisphenol S and 100 mL of methanol were charged, stirred and dissolved at room temperature, and while further stirring, a solution prepared by dissolving 4.0 g (0.1 mol) of sodium hydroxide in 50 mL of methanol in advance was added. Subsequently, a solution prepared by dissolving 41.9 g (0.1 mol) of tetraphenylphosphonium bromide in 150 mL of methanol in advance was added. Stirring was continued for a while, and after adding 300 mL of methanol, the solution in the flask was dropped into a large amount of water with stirring to obtain a white precipitate. The precipitate was filtered and dried. Thus, the target product of white crystals was obtained.

[0123] <Silane coupling agent (G)> (G-1) KBM-503 (Shin-Etsu Chemical Co., Ltd., 3-methacryloxypropyltrimethoxysilane) (G-2) X-12-967C (Shin-Etsu Chemical Co., Ltd., 3-trimethoxysilylpropylsuccinic anhydride, a silane coupling agent having a cyclic anhydride structure) (G-3) KBM-403 (Shin-Etsu Chemical Co., Ltd., 3-glycidoxypropyltrimethoxysilane)

[0124] <Surfactant (H)> (H-1) FC4432 (3M, fluorine-based surfactant)

[0125] <Organic solvent (I)> (I-1) Ethyl lactate (EL) (I-2) γ-butyrolactone (GBL)

[0126] <Water> (J-1) Distilled water

[0127] <Polymerization inhibitor> (K-1) Irganox 1035 (BASF, hindered phenol compound)

[0128] [Examples 1 to 3] The raw materials formulated according to Table 1 were stirred at room temperature until the raw materials were completely dissolved, yielding a solution. The solution was then filtered through a nylon filter with a pore size of 0.2 μm to obtain varnish-like core compositions of Examples 1 to 3. Hereinafter, the compositions of Examples 1 to 3 may also be referred to as Compositions A to C, respectively.

[0129] Examples and comparative examples of optical waveguides will be described below. First, the production of compositions D to F, which are raw materials for the optical waveguides, will be described.

[0130] <Production of Composition D> 26.0 parts by weight of epoxy resin (Nippon Kayaku Co., Ltd., product name: EPPN201, multifunctional epoxy resin, phenol novolac type epoxy resin), 7.8 parts by weight of phenoxy resin (Mitsubishi Chemical Corporation, product name: jER1256, bisphenol A type phenoxy resin), 0.8 parts by weight of photoacid generator (San-Apro Co., Ltd., product name: CPI-310B, onium salt compound), 0.1 parts by weight of surfactant (DIC Corporation, product name: R-41, fluorine-containing and lipophilic group-containing oligomer), and 0.3 parts by weight of silane coupling agent (Shin-Etsu Chemical Co., Ltd., product name: X-12-967C) were dissolved in 65.0 parts by weight of propylene glycol monomethyl ether acetate and mixed at room temperature for 2.5 hours to obtain a mixed solution. Next, pure water was added to the mixed solution so that the water content per 100% by weight of the composition was 7300 ppm, and the mixture was mixed again. The mixed solution was filtered through a 0.2 μm polypropylene filter to obtain Composition D in the form of a varnish.

[0131] <Preparation of Composition E> (Synthesis of cyclic olefin resin 1) Maleic anhydride (Nippon Shokubai Co., Ltd., 122.4 g, 1.25 mol), 2-norbornene (75 wt % toluene solution, Maruzen Petrochemical Co., Ltd., 156.8 g, 1.25 mol), and dimethyl 2,2'-azobis(2-methylpropionate) (V-601, Wako Pure Chemical Industries, Ltd., 11.5 g, 50 mmol) were weighed into an appropriately sized reaction vessel equipped with a stirrer and a condenser, and dissolved in methyl ethyl ketone (MEK, 150.8 g) and toluene (38.5 g). The solution was aerated with nitrogen for 10 minutes to remove oxygen, and then heated with stirring to 60° C. After 16 hours, MEK (320 g) was added to dilute the solution, and the solution was cooled. The reaction mixture was added dropwise to a large amount of methanol to precipitate the polymer. After filtering using a funnel, the polymer was washed with methanol and the solid was collected by filtration. The resulting polymer (hereinafter referred to as "precursor polymer") was vacuum dried at 70°C. The yield of the precursor polymer was 208.1 g, with a weight-average molecular weight (Mw) of 11,100 and a polydispersity (Mw / Mn) of 2.25. Subsequently, the above-mentioned precursor polymer (10.0 g) was weighed into a reaction vessel of appropriate size equipped with a stirrer and a cooling pipe and dissolved in MEK (30.0 g). Further, 2-hydroxyethyl methacrylate (HEMA, manufactured by Nippon Shokubai Co., Ltd., 8.5 g, 65 mmol) and sodium acetate (1.0 g) were added, and the mixture was heated at 70 °C for 8 hours. To this reaction solution, glycidyl methacrylate (GMA, 3.7 g, 26 mmol) was added, and the mixture was further stirred at 70 °C for 16 hours. After adding formic acid to the reaction solution for acid treatment, it was dropped into a large amount of pure water to precipitate the polymer. The solid collected by filtration was dried in a vacuum dryer at 40 °C for 16 hours to obtain 13.8 g of a pale yellow solid, Cyclic Olefin Resin 1. The properties of Cyclic Olefin Resin 1 were as follows. · Weight average molecular weight (Mw): 16,200 · Dispersion degree: 2.46

[0132] (Synthesis of Cyclic Olefin Resin 2) In a stirrer, into a reaction vessel of appropriate size equipped with a cooling pipe, maleic anhydride (MA, 122.4 g, 1.25 mol), 2-norbornene (NB, 117.6 g, 1.25 mol) and dimethyl 2,2'-azobis(2-methylpropionate) (11.5 g, 50.0 mmol) were weighed and dissolved in methyl ethyl ketone (MEK, 150.8 g) and toluene (77.7 g). Nitrogen was bubbled through this solution for 10 minutes to remove oxygen, and then it was heated with stirring at 60 °C for 16 hours. Then, after adding MEK (320 g) to this solution, it was added to a suspension of sodium hydroxide (12.5 g, 0.31 mol), 2-hydroxyethyl methacrylate (812.5 g, 6.25 mol), and toluene (480 g), and mixed at 45 °C for 3 hours. Then, this mixture was cooled to 40 °C, treated with formic acid (88 wt% aqueous solution, 49.0 g, 0.94 mol) to add protons, and then MEK and water were added, and the aqueous layer was separated to remove inorganic residues. Next, methanol and hexane were added, and the organic layer was separated to remove unreacted monomers. Further, PGMEA was added, and methanol and 2-hydroxyethyl methacrylate in the system were distilled off under reduced pressure until the residual amount was less than 1%. As a result, 1050.0 g of a 20 mass% polymer solution was obtained (GPC Mw = 17,800, Mw / Mn = 2.43). The obtained polymer was designated as cyclic olefin resin 2.

[0133] (Preparation of Composition E) 50 parts by mass of the cyclic olefin resin 1, 50 parts by mass (solids content) of the cyclic olefin resin 2, 20 parts by mass of a polyfunctional (meth)acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., product name: NK Ester A-DPH-SVF), 10 parts by mass of a bifunctional (meth)acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., product name: NK Ester 9G), 3 parts by mass of a photoradical generator (manufactured by BASF, product name: Irugacure OXE01), 1 part by mass of an adhesion aid (manufactured by Shin-Etsu Chemical Co., Ltd., product name: X-12-967C, silane coupling agent), and 1 part by mass of a surfactant (manufactured by DIC Corporation, product name: R-41, fluorine-containing group- and lipophilic group-containing oligomer) were dissolved in 223 parts by mass of propylene glycol monomethyl ether acetate (PGMEA) (parts by mass including the PGMEA contained in the cyclic olefin resin 2 solution), and mixed at room temperature to obtain a mixed solution. The mixed solution was filtered through a 0.2 μm filter to obtain a varnish-like composition E.

[0134] <Production of Composition F> (Synthesis of Cyclic Olefin Resin 3) Several glass instruments were prepared and dried at 60° C. under 0.1 Torr for 18 hours, and then all the glass instruments were placed in a glove box.

[0135] Next, toluene (992 g), dimethoxyethane (116 g), 1,1-bistrifluoromethyl-2-(bicyclo[2.2.1]hept-2-en-5-yl)ethyl alcohol (HFANB) (148 g, 0.54 mol), ethyl-3-(bicyclo[2.2.1]hept-2-en-2-yl)propanate (EPEsNB) (20.7 g, 0.107 mol), and 5-((2-(2-methoxyethoxy)ethoxy)methyl)bicyclo[2.2.1]hept-2-ene (NBTON) (61.9 g, 0.274 mol) were charged into one glass vessel (glass vessel X), and a mixture containing each monomer was obtained. The mixture was then heated at 45 °C and purged with nitrogen for 30 minutes.

[0136] In another glass apparatus (glass apparatus Y), EPEsNB (14.2 g, 0.073 mol) and NBTON (46.7 g, 0.159 mol) were mixed and purged with nitrogen. After the nitrogen purging was completely completed, bis(toluene)bis(perfluorophenyl)nickel (5.82 g, 0.012 mol) dissolved in 60.5 ml of toluene was added to glass apparatus Y. At the same time, the mixture in glass apparatus X was added to glass apparatus Y over 3 hours at a rate such that the polymerization reaction proceeded at a constant level, to obtain a reaction solution.

[0137] Next, the reaction solution was dissolved in approximately 1 L of a methanol / tetrahydrofuran (THF) (4 mol / 5 mol) solution to remove unreacted monomers. Next, the esters in the reaction solution were hydrolyzed with a sodium hydroxide / sodium acetate (4.8 mol / 1 mol) solution at 60 °C for 4 hours to obtain Solution A. Then, methanol (405 g), THF (87 g), acetic acid (67 g), formic acid (67 g), and deionized water (21 g) were added to Solution A and stirred at 50 °C for 15 minutes. When stirring was stopped, Solution A separated into an aqueous layer and an organic layer. The upper aqueous layer was removed, and the organic layer was washed three times with a methanol / deionized water (390 g / 2376 g) solution at 60 °C for 15 minutes. The resulting polymer was then diluted in propylene glycol methyl ether acetate and solvent-substituted to a polymer concentration of 40%. In this way, a polymer in solution (cyclic olefin resin 3) was obtained.

[0138] The yield of cyclic olefin resin 3 was 93.1%. The weight average molecular weight (Mw) of cyclic olefin resin 3 was 85,900. The molecular weight distribution (PD) of cyclic olefin resin 3 was 2.52.

[0139] The composition of the cyclic olefin resin 3 is 1 H-NMR revealed that the content was 45.0 mol % HFANB, 15.0 mol % 2-(bicyclo[2.2.1]hept-2-en-5-yl)propionic acid, and 40.0 mol % NBTON.

[0140] (Preparation of Composition F) 22.0 parts by mass (solid content) of the above cyclic olefin resin 3, 4.0 parts by mass of a photoacid generator (compound represented by the following formula (1)), 5.0 parts by mass of an epoxy compound (compound represented by the following formula (2)), 3.0 parts by mass of a phenolic compound (butyl 4-hydroxybenzoate), 2.0 parts by mass of an antioxidant (4,4'-bis(α,α-dimethylbenzyl)diphenylamine), 3.0 parts by mass of an antioxidant (2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenol), and 61.0 parts by mass of propylene glycol methyl ether acetate (including the propylene glycol methyl ether acetate contained in the cyclic olefin resin 3) were mixed to obtain a varnish-like composition F.

[0141] [Chemical Formula]

[0142] [Chemical Formula]

[0143] [Examples 4 to 6] (Manufacture of Optical Waveguide) (Formation of Underclad) The liquid films obtained by spin-coating Composition E on an 8-inch silicon wafer were heated at 110°C for 4 minutes to dry, and underclad layers with a thickness of 10 μm were each formed. Subsequently, with respect to the obtained underclad layers, using an automatic exposure machine, the entire surface was exposed with i-line having a wavelength of 365 nm at an exposure amount of 130 mJ / cm 2 , heated on a hot plate at 120°C for 2 minutes in the atmosphere, and the silicon wafers were heated at 200°C for 120 minutes in a nitrogen atmosphere to form underclads respectively.

[0144] (Formation of Core) The core compositions shown in Table 2 were spin-coated onto the underclad, and the resulting liquid coatings were dried at 110° C. for 3 minutes to form core layers each having a thickness of 7 μm. Next, the obtained core layer was exposed to i-line light of 365 nm wavelength at 1300 mJ / cm using an automatic exposure machine. 2 The film was exposed to an exposure dose of 10 μm, and developed with cyclopentanone and PGMEA using a spray developer. The film was then heated on a hot plate in the atmosphere at 120°C for 2 minutes, and the silicon wafer was then heated in a nitrogen atmosphere at 170°C for 120 minutes to form a core with a line width of 10 μm.

[0145] (Overclad formation) The liquid coating obtained by spin-coating composition E onto the core was heated at 110°C for 4 minutes and dried to form an overclad layer 17 μm thick from the underclad surface (10 μm thick from the core surface). Subsequently, the obtained overcladding layer was exposed to i-line light of 365 nm wavelength at 130 mJ / cm using an automatic exposure machine. 2 The entire surface was exposed to an exposure amount of 1000 ppm, and the wafer was heated on a hot plate in the atmosphere at 120° C. for 2 minutes. The silicon wafer was then heated in a nitrogen atmosphere at 200° C. for 120 minutes to form an overclad, thereby obtaining the optical waveguides of Examples 4 to 6, respectively.

[0146] [Examples 7 to 9] <Optical waveguide manufacturing> (Underclad formation) Composition F was spin-coated onto an 8-inch silicon wafer, and the resulting liquid film was dried by heating at 120° C. for 4 minutes to form an undercladding layer having a thickness of 10 μm. Subsequently, the silicon wafers on which the undercladding layers had been formed were heated in a nitrogen atmosphere at 230° C. for 120 minutes to form undercladding layers.

[0147] (Core formation) The cores were formed in the same manner as in Examples 4 to 6.

[0148] (Formation of Overclad) The liquid film obtained by spin-coating Composition F on the core was heated at 120 °C for 4 minutes to dry, and an overclad layer with a thickness of 17 μm from the underclad surface (10 μm from the core surface) was formed respectively. Subsequently, the silicon wafer with the overclad layer formed was heated in a nitrogen atmosphere at 230 °C for 120 minutes to form the overclad, and the optical waveguides of Examples 7 to 9 were obtained respectively.

[0149] [Comparative Example 1] (Manufacture of Optical Waveguide) (Formation of Underclad) The liquid film obtained by spin-coating Composition A on an 8-inch silicon wafer was heated at 110 °C for 3 minutes to dry, and an underclad layer with a thickness of 10 μm was formed. Subsequently, for the obtained underclad layer, using an automatic exposure machine, the entire surface was exposed with i-line of wavelength 365 nm at an exposure amount of 1300 mJ / cm 2 , heated on a hot plate in the air at 120 °C for 2 minutes, and the silicon wafer was heated in a nitrogen atmosphere at 170 °C for 120 minutes to form the underclad.

[0150] (Formation of Core) The liquid film obtained by spin-coating Composition D on the underclad was heated at 100 °C for 3 minutes to dry, and a core layer with a thickness of 7 μm was formed respectively. Subsequently, for the obtained core layer, using an automatic exposure machine, it was exposed with i-line of wavelength 365 nm at an exposure amount of 600 mJ / cm 2 , developed with cyclopentanone and PGMEA using a spray developer, then heated on a hot plate in the air at 70 °C for 5 minutes, and the silicon wafer was heated in a nitrogen atmosphere at 170 °C for 180 minutes to form a core with a line width of 10 μm.

[0151] (Formation of Overclad) The liquid film obtained by spin-coating Composition A on the core was heated at 110 °C for 3 minutes to dry it, and an overclad layer with a thickness of 17 μm from the underclad surface (10 μm from the core surface) was formed. Subsequently, for the obtained overclad layer, using an automatic exposure machine, the entire surface was exposed with i-line having a wavelength of 365 nm at an exposure dose of 1300 mJ / cm 2 , heated on a hot plate at 120 °C for 2 minutes in the atmosphere, and the silicon wafer was heated at 170 °C for 120 minutes in a nitrogen atmosphere to form an overclad, obtaining the optical waveguide of Comparative Example 1.

[0152] [Measurement and Evaluation] [Refractive Index Measurement of Composition] For the core composition of Example 1, the refractive index was measured based on the following conditions using a prism coupler (manufactured by Metricon). From the refractive index values at three wavelengths of the following measurement wavelengths, the refractive index at 30 °C and a wavelength of 1310 nm was calculated using the Cauchy dispersion formula. The refractive indices at 30 °C and a wavelength of 1310 nm for each example are shown in Table 1 respectively. Substrate: Si wafer Film thickness: 5 μm Measurement temperature: 30 °C Measurement wavelengths: 404 nm, 633 nm, 832 nm

[0153] [Absorbance Measurement of Composition] For the core composition of Example 1, based on the following conditions, the absorbance at 22 °C and a wavelength of 1310 nm was measured. The absorbance of the composition was the value obtained by dividing the measured value by the concentration of the measurement sample. Measurement device: Spectrophotometer (manufactured by JASCO Corporation, product name: V-670 EX) Test method: Parallel light transmittance measurement Measurement temperature: 22 °C Measurement wavelength: 1310 nm Measurement sample: Deuterated chloroform solution of the composition Concentration of the measurement sample: 20%

[0154] [Propagation Loss Evaluation of Optical Waveguide] (Environmental Test) The optical waveguides fabricated on silicon wafers of Examples 4 to 9 and Comparative Example 1 were subjected to an environmental test by heating them in an oven at 125° C. for 1000 hours, and optical waveguides after the environmental test were obtained.

[0155] (Propagation loss evaluation) The propagation loss of the optical waveguide before and after the environmental test was measured using the cutback method. Specifically, laser light with a wavelength of 1310 nm was incident on the core of the test piece via a single-mode optical fiber. Next, the intensity of the light emitted from the core of the test piece was obtained while changing the length of the test piece, and the propagation loss per unit length of the optical waveguide was calculated. The propagation loss of the optical waveguide was evaluated based on the following evaluation criteria. The evaluation results for each example and comparative example are shown in Table 2. A: The difference between the propagation loss of the optical waveguide after the environmental test and the propagation loss of the optical waveguide before the environmental test is less than 0.15 dB / cm B: The difference between the propagation loss of the optical waveguide after the environmental test and the propagation loss of the optical waveguide before the environmental test is 0.15 dB / cm or more and less than 0.40 dB / cm C: The difference between the propagation loss of the optical waveguide after the environmental test and the propagation loss of the optical waveguide before the environmental test is 0.40 dB / cm or more

[0156] [Table 1]

[0157] [Table 2]

[0158] As can be seen from Table 2, the optical waveguides of the examples all had good results in the propagation loss evaluation. That is, it can be seen that the core composition of this embodiment makes it possible to obtain an optical waveguide with improved thermal reliability. [Explanation of symbols]

[0159] 10 Underclad 20 cores 30 overclad 50 wafers 100 optical waveguides

Claims

1. A core composition that can be used for the core of an optical waveguide, comprising a polyimide resin (A) and a polyfunctional (meth)acrylate (B), the core composition.

2. The core composition according to claim 1, wherein the polyimide resin (A) contains a fluorine atom in the molecule.

3. The core composition according to claim 1 or 2, wherein the polyimide resin (A) contains an imide ring structure in the molecule.

4. The core composition according to claim 1 or 2, wherein the polyimide resin (A) contains a structural unit represented by the following general formula (a). 【Chemical 1】 (In the general formula (a), X is a divalent organic group, and Y is a tetravalent organic group)

5. The core composition according to claim 1 or 2, wherein the imidization rate of the polyimide resin (A) is 90% or more.

6. The core composition according to claim 1 or 2, wherein the polyfunctional (meth)acrylate (B) contains a (meth)acrylate compound (B1) having 5 or more functional groups.

7. The core composition according to claim 1 or 2, wherein the polyfunctional (meth)acrylate (B) contains a (meth)acrylate compound (B2) having 2 or more and 4 or less functional groups.

8. When the content of the polyimide resin (A) in the core composition is 100 parts by mass, the content of the polyfunctional (meth)acrylate (B) in the core composition is 20 parts by mass or more and 150 parts by mass or less. The core composition according to claim 1 or 2.

9. When the content of the polyimide resin (A) in the core composition is 100% by mass of the total solid content in the core composition, the content is 20% by mass or more. The core composition according to claim 1 or 2.

10. The core composition according to claim 1 or 2, further comprising a photosensitizer (C).

11. The core composition according to claim 1 or 2, further comprising a thermal radical generator (D).

12. The core composition according to claim 1 or 2, further comprising an epoxy compound (E).

13. The core composition according to claim 12, further comprising a curing catalyst (F) for the epoxy compound (E).

14. The core composition according to claim 1 or 2, further comprising a silane coupling agent (G).

15. The core composition according to claim 1 or 2, further comprising a surfactant (H).

16. The core composition according to claim 1 or 2, further comprising an organic solvent (I).

17. The core composition according to claim 1 or 2, which is in a varnish state.

18. The core composition according to claim 1 or 2, wherein the refractive index at 30 °C and a wavelength of 1310 nm is 1.500 or more and 1.560 or less.

19. The core composition according to claim 1 or 2, wherein the absorbance at 22 °C and a wavelength of 1310 nm is 0.020 or more and 0.050 or less.

20. A composition set comprising the core composition according to claim 1 or 2 and a cladding composition that can be used for the cladding of an optical waveguide.

21. The composition set according to claim 20, wherein the cladding composition contains a cyclic olefin resin and a polyfunctional (meth)acrylate.

22. The composition set according to claim 20, wherein the cladding composition contains a cyclic olefin resin and a phenol compound.

23. An optical waveguide comprising a core made of the core composition according to claim 1 or 2.

24. Comprising a silicon photonic device, The electronic device, wherein the silicon photonic device comprises the optical waveguide according to claim 23.

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