Resin composition for optical waveguides, resin composition for a substrate with optical waveguide, resin film, hardened object, and optical conductor board

Abstract

One purpose of the present invention is to provide a resin composition suitable for optical communication technologies. Another purpose is to provide a resin composition that can be used as an insulating resin for rewiring layers in electronics and also as the cladding resin for polymer optical waveguides, and that is suitable for filling the gap between chips, chip boards, etc., to protect the wiring and to enable the fabrication of highly integrated, energy-efficient, multifunctional devices based on various packing structures, including co-packed optics. The present inventors have carried out careful investigations and, as a result, discovered that a composition comprising a photocurable resin and a bismaleimide compound is useful as a resin composition for optical waveguides, thereby completing the invention.

Description

TECHNICAL FIELD

[0001] The present invention relates to a resin composition for optical waveguides, a resin composition for a substrate having an optical waveguide, a resin film, a cured article, and an optical circuit board. STATE OF THE ART

[0002] In recent years, there has been a demand for optical circuit boards to solve the problem of heat generation of circuit boards used in base station servers, which are part of the communications infrastructure, and to achieve energy savings. However, because optical communication technology consists of a combination of individual components, advanced integration technology has not yet been introduced.

[0003] In addition, there is still no technology for the simultaneous assembly of electrical and optical cables (co-packaging) to achieve advanced integration technology on existing printed circuit boards (packaging boards with IC chips mounted on them).

[0004] In existing printed circuit boards, the redistribution layer on the packaging substrate on which the chip is mounted is known to consist of copper wiring of a few micrometers based on copper foil and an insulating resin composition.

[0005] On the other hand, optical fibers of several tens of micrometers are mainly used for wiring in photonics (optical communication), but it is expected that optical waveguides made of polymers will be used due to the ongoing miniaturization to several micrometers to submicrometers.

[0006] The integration of multiple devices is being considered to achieve high-density packaging of low-power optical communication devices, and optoelectronic integrated packaging technology (co-packaged optics), a technology that simultaneously implements electrical communication technologies and optical communication technologies, is being considered. A packaging substrate structure has begun to be proposed in which optical communication devices, which were traditionally mounted as individual components, are miniaturized and integrated into a chip size and mounted together with telecommunications IC chips.

[0007] Patent Literature 1 discloses that in a packaging substrate on which an optoelectronic chip obtained from a III-V compound semiconductor wafer is mounted, a difference in the coefficient of linear expansion (CTE) from the IC chip obtained from a silicon wafer becomes a problem during mounting.

[0008] Patent Literature 2 discloses an arrangement in which a photonic chip is mounted in the form of being stacked on a FOWLP (Fan Out Wafer Level Package).

[0009] Patent Literature 3 describes an arrangement in which a silicon photonic chip with an optical transceiver function is mounted on a substrate.

[0010] In both cases, specific arrangements of optoelectronic integrated packages are shown, and insulating resin is required for the redistribution layer (RDL), which fills gaps to protect the wiring between chips and between chips and boards.

[0011] Furthermore, Patent Literature 4 discloses an epoxy resin composition characterized by its optical transparency as a selective wavelength absorbing composition for LIDAR (Laser Imaging Detection and Ranging) and having a light transmittance of 70% or more at 1550 nm, which is less likely to be discolored by heat, and which has high light resistance.

[0012] On the other hand, Patent Literature 5 discloses that a resin composition containing a bismaleimide resin is suitable for a redistribution layer for electronics.

[0013] Non-Patent Literature 1 shows a trend of assembling a package of an optical communication device that is miniaturized and highly integrated on a silicon wafer and an existing large-scale integrated circuit (LSI chip) on the same substrate. LITERATURE LISTPATENT LITERATURE Patent Literature 1: US Patent Application Publication No. 2021 / 0088737 Patent Literature 2: US Patent Application Publication No. 2018 / 0275359 Patent Literature 3: US Patent No. 10,025,047 Patent Literature 4: Japanese Patent No. 6899061 Patent literature 5: WO2021 / 154898A2 NON-PATENT LITERATURE

[0014] Non-patent literature 1: Optical Circuit Packaging Technology Committee, Optical Circuit Packaging Technology Study Group, “Current status and future prospects of Co-Packaged Optics”, Journal of the Japan Institute of Electronics Packaging, Vol. 24, No. 1, 2021, pp. 38-42 SUMMARY OF THE INVENTION TECHNICAL TASK

[0015] None of the resin compositions for the redistribution layer in the packaging structure of any of the above-mentioned optical communication devices provides a resin composition that simultaneously takes into account optical properties such as the refractive index in the near infrared, particularly in the C-band around the optical communication wavelength of 1550 nm, and low dielectric properties required in an insulating resin for assembling electronics suitable for current high-frequency applications.

[0016] In view of the above circumstances, the present invention aims to provide a resin composition suitable for optical communication technology.

[0017] Furthermore, in order to realize highly integrated, energy-saving and multifunctional devices through a variety of packaging structures for optoelectronic integrated packages, the present invention aims to provide a resin composition suitable for filling gaps between chips, between chips and boards, etc., to protect wiring, and which can be used as an insulating resin for redistribution layers of electronics and as a cladding resin for polymer optical waveguides. SOLUTION TO THE TASK

[0018] As a result of extensive research, the inventors discovered that a composition containing a photocurable resin and a bismaleimide compound is useful as a resin composition for optical waveguides, and completed the present invention. The present invention also provides a resin composition that has both optical properties enabling a cladding function suitable for an optoelectronic integrated packaging process that simultaneously packages optical communications, and low dielectric properties required for insulating a redistribution layer for electronics.

[0019] That is, the present invention relates to the following [1] to

[10] .

[0020] [1] A resin composition for optical waveguides comprising a photocurable resin and a bismaleimide compound.

[0021] [2] A resin composition for optical waveguides comprising a photocurable resin and a bismaleimide compound represented by the following general formula (1):

[0022] (In formula (1) R 1 a divalent hydrocarbon group derived from a dimer acid, R 2 represents a divalent organic group other than the divalent hydrocarbon group derived from a dimer acid, and R 3 is R 2 or R 1 . R 4 and R 5each independently contain one or more organic groups selected from: a tetravalent organic group having 6 to 40 carbon atoms and having a monocyclic or condensed polycyclic alicyclic structure; a tetravalent organic group having 4 to 40 carbon atoms in which organic groups having a monocyclic alicyclic structure are bonded to each other directly or via a cross-linked structure; a tetravalent organic group having 4 to 40 carbon atoms and having a semi-alicyclic structure with both an alicyclic structure and an aromatic ring; and a tetravalent organic group having 4 to 40 carbon atoms and having an alicyclic structure or an aromatic ring with a halogenated alkyl group. n is 0 to 100, and m is 0 to 100. However, when n=m=0, then R 3 R 1 .)

[0023] [3] The resin composition for optical waveguides according to [2], wherein the resins represented by R 4 and R 5 represented organic groups in the bismaleimide compound represented by formula (1) are any of the tetravalent organic groups represented by the following structural formulas (A-1) to (A-13).

[0024] (The bonds represented by * in the structural formulas are bonded to carbonyl carbon atoms forming a cyclic imide structure in the general formula (1).)

[0025] [4] The resin composition for optical waveguides according to [2], wherein the monomers represented by R 4 and R 5 organic groups in the bismaleimide compound represented by the general formula (1) are any of the tetravalent organic groups represented by the following structural formulas (A-3) to (A-6) and (A-8) to (A-11), and the bismaleimide compound the Hansen solubility parameters of a dispersion term δd of 16.6 MPa 1 / 2 or more and 21.2 MPa 1 / 2 or less, a polar term δp of 4.4 MPa 1 / 2 or more and 9.0 MPa 1 / 2 or less, and a hydrogen bond term δh of 4.4 MPa 1 / 2 or more and 9.2 MPa 1 / 2 or less.

[0026] [5] A resin composition for a substrate having an optical waveguide, comprising a photocurable resin and a bismaleimide compound represented by the above formula (1).

[0027] [6] The resin composition for a substrate with an optical waveguide according to [5], wherein the cations represented by R 4 and R 5 represented organic groups in the bismaleimide compound represented by the general formula (1) is any of the tetravalent organic groups represented by the above structural formulas (A-1) to (A-13).

[0028] [7] The resin composition for a substrate with an optical waveguide according to [5], wherein the alkyl groups represented by R 4 and R 5 represented organic groups in the bismaleimide compound represented by the general formula (1) are any of the tetravalent organic groups represented by the formulas (A-3) to (A-6) and (A-8) to (A-11), and the bismaleimide compound has a Hansen solubility parameter of a dispersion term δd of 16.6 MPa 1 / 2 or more and 21.2 MPa 1 / 2 or less, a polar term δp of 4.4 MPa 1 / 2 or more and 9.0 MPa 1 / 2 or less, and a hydrogen bond term δh of 4.4 MPa 1 / 2 or more and 9.2 MPa 1 / 2 or less.

[0029] [8] A resin film comprising the resin composition according to any one of [1] to [7].

[0030] [9] A cured product of the resin composition according to any one of [1] to [7].

[0031]

[10] An optical circuit board comprising the cured product according to [9]. Effect of the invention

[0032] According to the present invention, it is possible to provide a resin composition suitable for optical communication technology.

[0033] According to the present invention, it is also possible to provide a resin composition for rewiring having a cladding function for a polymer waveguide in a co-package for optoelectronic integrated packaging. DESCRIPTION OF THE EMBODIMENTS

[0034] The resin composition for optical waveguides according to the present embodiment will be described. It should be noted that the present invention is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0035] In this description, including examples, "parts" and "%" refer to mass unless otherwise stated.

[0036] In this description, “(meth)acrylate” includes both methacrylate and acrylate.

[0037] The resin composition for optical waveguides according to the present embodiment contains a photocurable resin and a bismaleimide compound described below. <Photohärtbares Harz>

[0038] Examples of photocurable resins include (meth)acrylates having at least one (meth)acryloyl group in the molecule. Examples of such (meth)acrylates include (meth)acrylates selected from the group consisting of monofunctional (meth)acrylates, polyfunctional (meth)acrylates, polyfunctional urethane (meth)acrylates, polyfunctional epoxy (meth)acrylates, and polyfunctional polyester (meth)acrylates.

[0039] Beispiele für monofunktionelle Monomere beinhalten Methyl(meth)acrylat, Ethyl(meth)acrylat, Propyl(meth)acrylat, n-Butyl(meth)acrylat, s-Butyl(meth)acrylat, tert-Butyl(meth)acrylat, Isobutyl(meth)acrylat, n-Pentyl(meth)acrylat, Isopentyl(meth)acrylat, Hexyl(meth)acrylat, Heptyl(meth)acrylat, Isoamyl(meth)acrylat, 2-Ethylhexyl(meth)acrylat, n-Octyl(meth)acrylat, Isooctyl(meth)acrylat, Isodecyl(meth)acrylat, Lauryl(meth)acrylat, 4-tert-Butylcyclohexanol(meth)acrylat, Tetrahydrofurfuryl(meth)acrylat, Benzyl(meth)acrylat, Dicyclopentenyl(meth)acrylat, Dicyclopentenyloxyethyl(meth)acrylat, Dicyclopentanyl(meth)acrylat, Nonylphenolpolyethylenglykol(meth)acrylat und Isobornyl(meth)acrylat; Carboxylgruppen enthaltende Monomere wie (Meth)acrylsäure, (Meth)acrylsäure-Dimer, Carboxyethyl-(Meth)acrylat, Carboxypentyl-(Meth)acrylat und ω-Carboxy-Polycaprolacton-(Meth)acrylat;Heterocyclus-haltige (Meth)acrylate wie N-Acryloylmorpholin, N-Vinylpyrrolidon, N-Vinylcaprolactam, N-Acryloylpiperidin, N-Methacryloylpiperidin, N-Acryloylpyrrolidin, 3-(3-Pyridin)propyl-(Meth)acrylat und cyclisches Trimethylolpropanformalacrylat; Maleinimidmonomere wie Maleinimid, N-cyclohexylmaleinimid und N-Phenylmaleinimid; N-substituierte Amidmonomere wie (Meth)acrylamid, N,N-Dimethyl(meth)acrylamid, N,N-Diethyl(meth)acrylamid, N-Hexyl(meth)acrylamid, N-Methyl(meth)acrylamid, N-Butyl(meth)acrylamid, N-Methylol(meth)acrylamid und N-Methylolpropan(meth)acrylamid; Aminoalkyl(meth)acrylatmonomere wie Aminoethyl(meth)acrylat, Aminopropyl(meth)acrylat, N,N-Dimethylaminoethyl(meth)acrylat und tert-Butylaminoethyl(meth)acrylat; und Succinimidmonomere wie N-(Meth)acryloyloxymethylensuccinimid, N-(Meth)acryloyl-6-oxyhexamethylensuccinimid und N-(Meth)acryloyl-8-oxyoctamethylensuccinimid.;

[0040] Beispiele für polyfunktionelle Monomere beinhalten Ethylenglycoldi(meth)acrylat, Polyethylenglycoldi(meth)acrylat, Polypropylenglycoldi(meth)acrylat, Neopentylglycoldi(meth)acrylat, Tripropylenglycoldi(meth)acrylat, Di(meth)acrylat eines Alkylenoxidaddukts von Bisphenol A, Tetraethylenglycoldi(meth)acrylat, Hydroxypivalinsäure-Neopentylglycoldi(meth)acrylat, 1,4-Butandioldi(meth)acrylat, 1,6-Hexandioldi(meth)acrylat, 1,9-Nonandioldi(meth)acrylat, 1,12-Dodecandioldi(meth)acrylat, 1,14-Tetradecandioldi(meth)acrylat, 1,16-Hexadecandioldi(meth)acrylat, 1,20-Eicosandioldi(meth)acrylat, Isopentyldioldioldi(meth)acrylat, 3-Ethyl-1,8-octandioldi(meth)acrylat, Di(meth)acrylat des EO-Addukts von Bisphenol A, Trimethylolpropantri(meth)acrylat, Trimethyloloctantri(meth)acrylat, Trimethylolpropan-polyethoxytri(meth)acrylat, Trimethylolpropanpolypropoxytri(meth)acrylat, Trimethylolpropanpolyethoxypolypropoxytri(meth)acrylat, Tris[(meth)acryloyloxyethyl]isocyanurat, Pentaerythritoltri(meth)acrylat,Pentaerythritol polyethoxytetra(meth)acrylate, pentaerythritol polypropoxytetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropantetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate and caprolactone-modified Tris[(meth)acryloyloxyethyl]isocyanurate.,

[0041] Among these, mono- and bifunctional (meth)acrylates are preferred due to their low viscosity. In particular, monofunctional epoxy acrylates containing a phenoxy group and 1,6-hexanediol diacrylate are preferred from the perspectives of viscosity and compatibility with the maleimide resin.

[0042] From the perspective of the viscosity of the composition, the content of the phenoxy group-containing monofunctional epoxy acrylate is 10% by weight or less, preferably 1% by weight or less, based on 100% by weight of the resin component. The content of 1,6-hexanediol diacrylate is 3% by weight or more and 25% by weight or less, preferably 20% by weight or more and 25% by weight or less. <bismaleinimidverbindung>

[0043] The bismaleimide compound is not particularly limited as long as it has maleimide structures at both ends of the molecule. The bismaleimide compound is preferably a compound having two or more imide structures.

[0044] The bismaleimide compound is preferably a bismaleimide compound represented by the following formula (1).

[0045] In formula (1), R 1 a divalent hydrocarbon group derived from a dimer acid, R 2 represents a divalent organic group other than the divalent hydrocarbon group derived from the dimer acid, and R 3 is R 2 or R 1 . R 4 and R 5 each independently contain one or more organic groups selected from: a tetravalent organic group having 6 to 40 carbon atoms and having a monocyclic or condensed polycyclic alicyclic structure; a tetravalent organic group having 4 to 40 carbon atoms in which organic groups having a monocyclic alicyclic structure are bonded to each other directly or via a cross-linked structure; a tetravalent organic group having 4 to 40 carbon atoms and having a semi-alicyclic structure that has both an alicyclic structure and an aromatic ring; and a tetravalent organic group having 4 to 40 carbon atoms and having an alicyclic structure or an aromatic ring with a halogenated alkyl group. n is 0 to 100, and m is 0 to 100. However, when n=m=0, R 3 R 1 .

[0046] Here, the divalent hydrocarbon group derived from the dimer acid, represented by R 1 represented in formula (1) refers to a divalent radical obtained by removing two carboxy groups from a dicarboxylic acid contained in the dimer acid.

[0047] In this embodiment, the dimer acid is obtained by dimerizing unsaturated bonds of unsaturated carboxylic acids having 18 carbon atoms, such as linoleic acid, oleic acid, and linolenic acid, followed by purification by distillation. The dimer acid mainly contains a dicarboxylic acid having 36 carbon atoms and usually up to about 5% by weight of a tricarboxylic acid having 54 carbon atoms and up to about 5% by weight of a monocarboxylic acid. The dimer acid-derived diamine according to this embodiment (hereinafter sometimes referred to as a dimer acid-derived diamine) is a diamine obtained by substituting two carboxyl groups of each dicarboxylic acid contained in the dimer acid with amino groups. Usually, the dimer acid-derived diamine is a mixture of several types.Examples of such a dimer acid-derived diamine include diamines such as [3,4-bis(1-aminoheptyl)6-hexyl-5-(1-octenyl)]cyclohexane and diamines in which the unsaturated bonds are saturated by further hydrogenation of these diamines.

[0048] The dimer acid-derived dihydric hydrocarbon according to the present embodiment, which is introduced into the bismaleimide compound using such a dimer acid-derived diamine, is preferably a residue obtained by removing two amino groups from the dimer acid-derived diamine. When the dimer acid-derived diamine is used to obtain the bismaleimide compound according to the present embodiment, the dimer acid-derived diamine can be used alone or in combination with two or more dimer acid-derived diamines having different compositions. In addition, as such a dimer acid-derived diamine, for example, a commercially available product such as "PRIAMINE 1074" (manufactured by Croda Japan Co., Ltd.) can be used.

[0049] The energy in formula (1) represented by R 2 The divalent organic group represented by the formula (I) other than the divalent hydrocarbon group derived from the dimer acid is an alkylene group having 6 to 60 carbon atoms, which may contain a heteroatom, or an arylene group having 6 to 30 carbon atoms, which may contain a heteroatom. Preferably, it is an alkylene group having 8 to 40 carbon atoms, which may contain a heteroatom, or an arylene group having 8 to 18 carbon atoms.

[0050] It is preferable that R 2 in the above formula (1) is any alkylene group having an aliphatic ring or an arylene group having an aromatic ring as represented by the following structural formulas (B-1) to (B-4).

[0051] The bonds represented by * in structural formulas (B-1) to (B-4) are bonds to the nitrogen atom in formula (1).

[0052] The organic groups represented in formula (1) by R 4 and R 5 each independently represents a tetravalent organic group containing a cyclic structure, and are particularly preferably any of the tetravalent organic groups represented by the following structural formulas (A-1) to (A-13).

[0053] The bonds represented by * in structural formulas (A-1) to (A-13) are bonded to the carbonyl carbons forming the cyclic imide structure in formula (1). Formula (A-10) is a structure derived from a tetracarboxylic acid dianhydride, represented by the following structural formula (A-10-A).

[0054] In formula (1), m is the number of repeating units containing a divalent hydrocarbon group derived from a dimer acid R1 (hereinafter sometimes referred to as a structure derived from dimer acid), and represents an integer from 0 to 100. From the viewpoint of favorable solubility in a developer during development, the value of m is particularly preferably 0 to 10.

[0055] In formula (1), n ​​is the number of repeating units (hereinafter sometimes referred to as a structure derived from an organic diamine) containing another divalent organic group R 2 as the divalent hydrocarbon group derived from the dimer acid, and represents an integer from 0 to 100. As the value of n increases, the flexibility of the resulting cured product deteriorates, resulting in a hard and brittle resin. In view of the flexibility and elastic modulus of the cured product, it is particularly preferable that the value of n be from 0 to 10.

[0056] Furthermore, in the bismaleimide compound represented by the formula (1), the structure derived from the dimer acid and the structure derived from the organic diamine may be randomly copolymerized or block copolymerized.

[0057] The bismaleimide compound represented by formula (1) can be obtained by reacting a diamine derived from a dimer acid and, if necessary, an organic diamine other than that derived from the dimer acid, with a tetracarboxylic acid dianhydride and maleic anhydrides.

[0058] The method for reacting a diamine derived from a dimer acid with a tetracarboxylic dianhydride and maleic anhydrides, or the method for reacting a diamine derived from a dimer acid and an organic diamine with a tetracarboxylic dianhydride and maleic anhydrides, is not particularly limited, and any known method can be used where appropriate. For example, first, a diamine derived from a dimer acid, a tetracarboxylic dianhydride, and, if necessary, an organic diamine other than the dimer acid-derived diamine are stirred in a solvent such as toluene, xylene, tetralin, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, or a mixed solvent thereof at room temperature (about 23°C) for 30 to 60 minutes to synthesize a polyamic acid.Maleic acid is then added to the resulting polyamic acid, and stirring is continued for 30 to 60 minutes at room temperature (about 23°C) to synthesize a polyamic acid to which maleic acid has been added at both ends. A solvent that forms an azeotrope with water, such as toluene, is added to the polyamic acid, and the mixture is refluxed at a temperature of 100 to 160°C for 3 to 6 hours, while removing the water formed during the imide formation to obtain the desired bismaleimide compound. A catalyst such as pyridine or methanesulfonic acid may also be added in this process.

[0059] The bismaleimide compound is preferably a bismaleimide compound with the Hansen solubility parameters of a dispersion term δd of 16.6 MPa 1 / 2 or more and 21.2 MPa 1 / 2 or less, a polar term δp of 4.4 MPa 1 / 2 or more and 9.0 MPa 1 / 2 or less, and a hydrogen bond term δh of 4.4 MPa 1 / 2 or more and 9.2 MPa 1 / 2 or less.

[0060] The bismaleimide compound with Hansen solubility parameters of the dispersion term δd of 16.6 MPa 1 / 2 or more and 21.2 MPa 1 / 2 or less, a polar term δp of 4.4 MPa 1 / 2 or more and 9.0 MPa 1 / 2 or less and a hydrogen bond term δh of 4.4 MPa 1 / 2 or more and 9.2 MPa 1 / 2 or less is preferably a bismaleimide represented by the formula (1). In the formula (1), the alkyl radicals represented by R 1 represented divalent hydrocarbon group derived from the dimer acid and represented by R 2 represented divalent organic group which is different from the divalent hydrocarbon group derived from the dimer acid as described above.

[0061] Furthermore, the values ​​of δp and δh increase as the divalent organic group other than the divalent hydrocarbon group derived from the dimer acid increases, and tend to exceed the above-mentioned parameter ranges. Therefore, for a bismaleimide compound that satisfies the Hansen solubility parameters, it is preferable that m and n in formula (1) satisfy the relationship m>n.

[0062] In the bismaleimide compound that satisfies the Hansen solubility parameters, the organic groups represented by R 4 and R 5 represented in formula (1) each independently represents a tetravalent organic group containing a cyclic structure, and is particularly preferably a tetravalent organic group having a six-membered alicyclic skeleton, a tetravalent organic group having an aromatic ring skeleton containing a halogenated alkyl group, a tetravalent organic group having a monocyclic or condensed polycyclic alicyclic structure, or an organic group in which organic groups having a monocyclic alicyclic structure are bonded to each other directly or via a cross-linked structure. In particular, any of the tetravalent organic groups represented by the following structural formulas (A-3) to (A-6) and (A-8) to (A-11) is preferred.

[0063] As the bismaleimide compound according to the present embodiment, a compound represented by the following formula (M-1), a compound represented by the following formula (M-2), a compound represented by the following formula (M-3), a compound represented by the following formula (M-4), a compound represented by the following formula (M-5), or a compound represented by the following formula (M-6) is preferable. Moreover, as the bismaleimide compound according to the present embodiment, one kind may be used alone, or two or more kinds may be used in combination. In the following formulas (M-1) to (M-5), n is preferably 1 to 10 from the viewpoint of compatibility, and more preferably 1 to 3.

[0064] The Hansen solubility parameters are the solubility parameters introduced by Hildebrand, which are divided into three components: a dispersion term (δd), a polar term (δp), and a hydrogen bond term (δh), and expressed in a three-dimensional space. The dispersion term (δd) indicates the effect of dispersion forces, the polar term (δp) the effect of dipolar intermolecular forces, and the hydrogen bond term (δh) the effect of hydrogen bond forces.

[0065] The definition and calculation method of the Hansen solubility parameters are described, for example, in "Hansen Solubility Parameters: A Ser Handbook" by Charles M. Hansen, CRC Press, 2007, etc. The calculation can also be performed using the computer software "Hansen Solubility Parameters in Practice (HSPiP)".

[0066] In this experiment, a bismaleimide compound was stirred with 13 types of organic solvents (N,N-dimethylformamide, ethyl acetate, cyclopentanone, methanol, methyl ethyl ketone, methyl isobutyl ketone, N-methylpyrrolidone, anisole, isopropyl alcohol, propylene glycol monomethyl ether acetate, toluene, water, ethylene glycol diglycidyl ether) in a ratio of 1:9 each, heated in a thermostatic bath at 80°C for 1 hour to make the solutions uniform, and then allowed to stand overnight. The compatibility degree of the solution after standing overnight was rated from 1 to 6, and the results were entered into the software for calculation. Regarding the compatibility degree in this description, level 1 means complete compatibility. Level 2 means a transparent solution with slight turbidity. Level 3 indicates that the entire solution is cloudy or that some of the compounds have precipitated.Level 4 indicates that the compounds in the entire solution are swollen or that more than half of the compounds are incompatible and have precipitated. Level 5 indicates that the solution is completely suspended or that only a portion of the compounds are compatible. Level 6 indicates that the compounds are incompatible, completely swollen, or separated. The Hansen solubility parameters in this description were calculated using HSPiP version 5.4.01.

[0067] From the viewpoint of viscosity and compatibility of the composition, the content of the bismaleimide compound is 60% by weight or more and 80% by weight or less, preferably 70% by weight or more and 80% by weight or less, based on 100% by weight of the resin component. <photopolymerisationsinitiator>

[0068] The resin composition for optical waveguides according to this embodiment may contain a photopolymerization initiator described below. The photopolymerization initiator can be appropriately selected from known radical photopolymerization initiators. Examples of the photopolymerization initiator include: radical photocuring initiators such as: benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, and benzoin isobutyl ether; organic peroxides such as benzoyl peroxide, lauroyl peroxide, acetyl peroxide, parachlorobenzoyl peroxide, and di-tert-butyl diperphthalate; phosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, benzoyldiphenylphosphine oxide, and bisbenzoylphenylphosphine oxide;Acetophenones such as acetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 2-hydroxy-2-methyl-phenylpropan-1-one, diethoxyacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one and 2-Benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1; anthraquinones such as 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-chloroanthraquinone and 2-amylanthraquinone; Thioxanthones such as 2,4-diethylthioxanthone, 2-isopropylthioxanthone and 2-chlorothioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; Benzophenones such as benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide and 4,4'-bismethylaminobenzophenone; oxime esters such as 1-[4-(phenylthio)phenyl]-1,2-octanedione-2-(O-benzoyloxime) and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone-1-(O-acetyloxime) and cationic photopolymerization initiators such as: diazonium salts of Lewis acids, such as p-methoxyphenyldiazonium fluorophosphonate and N,N-diethylaminophenyldiazonium hexafluorophosphonate;iodonium salts of Lewis acids, such as diphenyliodonium hexafluorophosphonate and diphenyliodonium hexafluoroantimonate; sulfonium salts of Lewis acids, such as triphenylsulfonium hexafluorophosphonate and triphenylsulfonium hexafluoroantimonate; phosphonium salts of Lewis acids, such as triphenylphosphonium hexafluoroantimonate; other halides; triazine-based initiators; borate-based initiators; and other photoacid generators.

[0069] Commercially available products can be used as photopolymerization initiators, for example Omnirad (registered trademark) 369 (trade name) manufactured by IGM Resins BV, Omnirad (registered trademark) 819 (trade name) manufactured by IGM Resins BV, Omnirad (registered trademark) 819DW (trade name) manufactured by IGM Resins BV, Omnirad (registered trademark) 907 (trade name) manufactured by IGM Resins BV, Omnirad (registered trademark) TPO (trade name) manufactured by IGM Resins BV, Omnirad (registered trademark) TPO-G (trade name) manufactured by IGM Resins BV, Omnirad (registered trademark) 784 (trade name) manufactured by BASF Corporation, Irgacure (registered trademark) OXE01 (trade name) manufactured by BASF Japan Ltd, Irgacure (registered trademark) OXE02 (trade name) manufactured by BASF Japan Ltd, Irgacure (registered trademark) OXE03 (trade name) manufactured by BASF Japan Ltd, and Irgacure (registered trademark) OXE04 (trade name) manufactured by BASF Japan Ltd.These photopolymerization initiators (C) can be used alone or in suitable mixtures of two or more kinds.

[0070] In this embodiment, the C-band is an optical communication signal in the near-infrared range of 1535-1565 nm and is cited as a wavelength range generally used in optical fiber communications. However, this does not preclude the use of optical communication media with surrounding wavelength ranges such as the O-band, S-band, and L-band.

[0071] The cured product of the optical waveguide resin composition can simultaneously achieve two effects: 1) a low loss factor and 2) a refractive index in the C-band (1550 nm) within a range suitable for optical waveguides. In this specification, a refractive index within a range suitable for optical waveguides means a value of less than 1.6, which is particularly suitable when the optical waveguide resin composition is used as a cladding material. A refractive index of 1.6 or more can be considered suitable as a core material in optical waveguides.

[0072] The resin composition for optical waveguides can be a resin composition or a resin film. The resin composition has flowability. The resin composition can be in a paste form. The paste form includes a liquid form.

[0073] The resin composition for an optical waveguide is preferably a photocurable material. When the resin composition is a resin film, the resin film is preferably a photocurable resin film.

[0074] The resin composition for optical waveguides is preferably cured by exposure (photocuring). Examples of light rays for exposure include ultraviolet rays, electron beams, and X-rays. Examples of light sources that can be used for ultraviolet irradiation include sunlight, chemical lamps, low-pressure mercury lamps, high-pressure mercury lamps, metal halide lamps, xenon lamps, and UV LEDs. After irradiation, post-baking may be performed to stabilize the physical properties of the cured product. The method of post-baking is not particularly limited, but is usually performed at 50 to 260°C for 1 to 120 minutes using a hot plate, oven, or the like.

[0075] The cured product has a refractive index of approximately 1.4 at a wavelength of 1,550 nm and is suitable as a material for the production of an optical waveguide.

[0076] The resin composition for optical waveguides can also be used as a resin composition for an optical waveguide substrate. For example, a core material can be embedded in the resin composition for an optical waveguide substrate to form a plate, thereby forming an optical waveguide substrate with a built-in core material. In this case, the resin composition for an optical waveguide substrate also functions as a cladding material for the optical waveguide.

[0077] The present invention also relates to an optical waveguide, an optical circuit board or a substrate having an optical waveguide, which are manufactured using the resin composition for an optical waveguide or the resin composition for a substrate having an optical waveguide.

[0078] In the optical waveguide of this embodiment, the resin composition can be used both as a cladding material for forming the cladding part of the optical waveguide and as a material for forming the core part, but is particularly suitable as a cladding material because the cured product has a low refractive index.

[0079] Furthermore, for the optical waveguide, various materials used to form the cladding part and the core part of conventional optical waveguides, that is, materials that are cured by light irradiation or heat treatment, such as materials mainly composed of silicone resin, acrylic resin, vinyl resin, epoxy resin, polyimide resin, polyolefin resin, polynorbornene resin, etc., can be appropriately selected and used as the cladding forming material and the core forming material. Specifically, the above-mentioned optical waveguide manufacturing composition and various conventional materials can be selected and used as the respective manufacturing materials, so that the cladding part formed by the cladding forming material has a lower refractive index than the core part formed by the core forming material.The cladding material may also contain a light-absorbing material such as soot.

[0080] The method for manufacturing the optical waveguide is not particularly limited. For example, the optical waveguide can be formed by a method of curing the optical waveguide-forming composition of the present embodiment or the above-mentioned conventional materials by exposure (photocuring) or heating (thermal curing). As a representative example, the optical waveguide can be formed by a development process using a lithographic technique with a photomask.

[0081] In addition, so-called "optical pins" (optical waveguides having a desired tilt angle with respect to the substrate surface), which are a form of optical waveguides, can also be suitably produced using the composition for forming optical waveguides.

[0082] Optical waveguides with such a desired tilt angle can be manufactured, for example, by the manufacturing method described in WO2015 / 060190. Specifically, the optical waveguide can be manufactured by a method comprising the steps of: (1) providing an antireflection film on a substrate, (2) disposing the optical waveguide-forming composition on the antireflection film, exposing the optical waveguide-forming composition to light incident in a direction non-perpendicular to the substrate surface through a photomask, and curing the composition, and (3) removing the unexposed optical waveguide-forming composition by development.

[0083] The anti-reflection film is not particularly limited, but a preferable example is an anti-reflection film formed from the anti-reflection film-forming composition described in WO 2015 / 060190 (a polymerizable composition containing a reactive silicone compound obtained by polycondensation of a diaryl silicate compound having a specific structure and an alkoxysilane compound having a specific structure in the presence of an acid or a base, and an ultraviolet absorber).

[0084] Furthermore, a gradient index optical waveguide (Gl type) can also be manufactured using the above-mentioned composition for manufacturing optical waveguides, for example, using the manufacturing method described in WO2013 / 002013, i.e., an injection method (so-called mosquito method) in which a curable core resin is molded into a curable cladding resin by means of a dispenser. Examples[Preparation of the resin composition] <bismaleinimidverbindung>

[0085] The following four compounds were prepared as bismaleimide compounds. (A-1) Bismaleimide compound

[0086] Synthesized according to Synthesis Example 1 of WO2020 / 203834. Weight-average molecular weight (Mw): 3200 (Formula (M-3) above) (A-2) Bismaleimide compound

[0087] Trade name "MIZ-001", manufactured by Nippon Kayaku Co., Ltd., weight-average molecular weight (Mw): 3000 (above formula (M-1)) (A-3) Bismaleimide compound

[0088] Compound (A3) was synthesized according to Synthesis Example 4 of WO2020 / 203834. Weight-average molecular weight (Mw): 3700 (formula (M-2) above) (A-4) Bismaleimide compound

[0089] Trade name "BMI-689", manufactured by Designer Molecules Inc, weight average molecular weight (Mw): 690 (above formula (M-6)) <Photohärtbares Harzmonomer>

[0090] An epoxy acrylate monomer having a phenoxy group (manufactured by Nippon Kayaku Co., Ltd., product name “R-128H”) and 1,6-hexanediol diacrylate (HDDA) (manufactured by IGM Resins BV, product name “Photomer 4017”) were prepared as light-curable resin monomers. <photopolymerisationsinitiator>

[0091] 2,4,6-Trimethylbenzoyldiphenylphosphine oxide (manufactured by IGM Resins BV, trade name “Omnirad TPO”) was prepared as a photopolymerization initiator. <harzzusammensetzung>

[0092] The above bismaleimide compound, a photocurable resin monomer, and a photopolymerization initiator were mixed to prepare a resin composition.

[0093] In Table 1, the numerical values ​​of the bismaleimide compounds (A-1) to (A-4), the photocurable resin monomers (R-128H, HDDA), and the photopolymerization initiator (TPO) are the contents (wt%) based on the total amounts of the bismaleimide compounds, the photocurable resin monomers, and the photopolymerization initiator. [Production of the resin film]

[0094] The resin composition was placed between 5 mm thick glass substrates, onto which a 75 µm thick untreated PET film (manufactured by Teijin, product name "Teijin Tetron (registered trademark) Film, HSL-Type") was applied, the film thickness was adjusted with a 100 µm spacer, and the resin film was cured at 1800 mJ / cm 2 cured with a high-pressure mercury lamp (80 W / cm, ozone-free) to produce a resin film.

[0095] The obtained resin film was used for the following evaluations. <Hansen Löslichkeitsparameter>

[0096] The dispersion term (δd), the polar term (δp) and the hydrogen bond term (δh) of the Hansen solubility parameters of the bismaleimide compounds (A-1) to (A-4) were calculated using HSPiP version 5.4.01. <Kompatibilität>

[0097] Resin films that appeared transparent and clear were rated "good," while those that were cloudy were rated "poor." <Dielektrizitätskonstante und Verlustfaktor>

[0098] The resin films were cut into test pieces with a length of 80 mm and a width of 3 mm, and the dielectric properties (dielectric constant and loss factor) were measured by the cavity perturbation method using a 10 GHz cavity manufactured by AET Corporation. <brechungsindex>

[0099] A resin film was cut into a 50 mm square, which served as a test piece, and the reflectance of light with a wavelength of 1550 nm was measured. The refractive index was calculated from the reflectance using the Fresnel equation. [Table 1] Example 1 Example 2 Example 3 Example 4 A-1 71,33 - - - A-2 - 71,33 - - A-3 - - 71,33 - A-4 - - - 71,33 R-128H 0,99 0,99 0,99 0,99 HDDA 24,77 24,77 24,77 24,77 TPO 2,91 2,91 2,91 2,91 δd 17,70 17,60 18,00 16,70 δp 6,50 7,60 6,90 8,40 δh 5,50 6,70 4,40 6,90 compatibility good good good good Dielectric constant 2,54 2,58 2,56 2,56 Loss factor 0,0077 0,0074 0,0075 0,0075 Refractive index (1550nm) 1,462 1,462 1,469 1,469 INDUSTRIAL APPLICABILITY

[0100] The present invention provides a resin composition for optical waveguides having a refractive index applicable to optical waveguides at 1550 nm, and suitable as a cladding material for polymeric optical waveguides used to realize advanced integration of optoelectronic integrated packaging in which low-power optical communications are mixed and mounted on an electrical communication board. Furthermore, a resin composition for redistribution layers of mixed packages with optical components is provided, which has a refractive index suitable for optical waveguides and the low dielectric properties required for redistribution layers (RDLs) in electronic IC chip assembly.

[0101] This application claims priority to Japanese Patent Application No. 2022-079430, filed on May 13, 2022. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 2021 / 0088737

[0013] US 2018 / 0275359

[0013] US 10,025,047

[0013] JP 6899061

[0013] WO 2021 / 154898A2

[0013] WO 2015 / 060190 [0082, 0083] WO 2013 / 002013

[0084] WO 2020 / 203834 [0086, 0088] JP 2022-079430

[0101] Cited non-patent literature

[0000] Optical Circuit Packaging Technology Committee, Optical Circuit Packaging Technology Study Group, „Current status and future prospects of Co-Packaged Optics", Journal of the Japan Institute of Electronics Packaging, Vol. 24, No. 1, 2021, S. 38-42

[0014] Hansen Solubility Parameters: A ser Handbook" von Charles M. Hansen, CRC Press, 2007

[0065] < / brechungsindex> < / harzzusammensetzung> < / photopolymerisationsinitiator> < / bismaleinimidverbindung> < / photopolymerisationsinitiator> < / bismaleinimidverbindung>

Claims

[1] A resin composition for optical waveguides comprising a photocurable resin and a bismaleimide compound. [2] A resin composition for optical waveguides comprising a photocurable resin and a bismaleimide compound represented by the following general formula (1): (in formula (1), R 1 a divalent hydrocarbon group derived from a dimer acid, R 2 represents a divalent organic group other than the divalent hydrocarbon group derived from a dimer acid, and R 3 is R 2 or R 1 , R 4 and R 5each independently contain one or more organic groups selected from: a tetravalent organic group having 6 to 40 carbon atoms and having a monocyclic or condensed polycyclic alicyclic structure; a tetravalent organic group having 4 to 40 carbon atoms in which organic groups having a monocyclic alicyclic structure are bonded to each other directly or via a cross-linked structure; a tetravalent organic group having 4 to 40 carbon atoms and having a semi-alicyclic structure having both an alicyclic structure and an aromatic ring; and a tetravalent organic group having 4 to 40 carbon atoms and having an alicyclic structure or an aromatic ring having a halogenated alkyl group, n is 0 to 100, and m is 0 to 100, but when n=m=0, R 3 R 1 ). [3] The resin composition for optical waveguides according to claim 2, wherein the monomers represented by R 4 and R 5 represented organic groups in the bismaleimide compound represented by formula (1) are any of the tetravalent organic groups represented by the following structural formulas (A-1) to (A-13): (wherein bonds represented by the characters * in the structural formulas are bonded to carbonyl carbon atoms forming a cyclic imide structure in the general formula (1)). [4] The resin composition for optical waveguides according to claim 2, wherein the monomers represented by R 4 and R 5represented organic groups in the bismaleimide compound represented by the general formula (1) are any of the tetravalent organic groups represented by the following structural formulas (A-3) to (A-6) and (A-8) to (A-11), and the bismaleimide compound has the Hansen solubility parameter of a dispersion term δd of 16.6 MPa 1 / 2 or more and 21.2 MPa 1 / 2 or less, a polar term δp of 4.4 MPa 1 / 2 or more and 9.0 MPa 1 / 2 or less, and a hydrogen bond term δh of 4.4 MPa 1 / 2 or more and 9.2 M Pa 1 / 2 or less (wherein bonds represented by * in the structural formulas are bonded to carbonyl carbon atoms forming a cyclic imide structure in the general formula (1)). [5] A resin composition for a substrate having an optical waveguide, comprising a photocurable resin and a bismaleimide compound represented by the following general formula (1): (in the formula (1), R 1 a divalent hydrocarbon group derived from a dimer acid, R 2 represents a divalent organic group other than the divalent hydrocarbon group derived from a dimer acid, and R 3 is R 2 or R 1 , R 4 and R 5each independently contain one or more organic groups selected from a tetravalent organic group having 6 to 40 carbon atoms and having a monocyclic or condensed polycyclic alicyclic structure, a tetravalent organic group having 4 to 40 carbon atoms in which organic groups having a monocyclic alicyclic structure are bonded to each other directly or via a bridged structure, a tetravalent organic group having 4 to 40 carbon atoms and a semi-alicyclic structure having both an alicyclic structure and an aromatic ring, and a tetravalent organic group having 4 to 40 carbon atoms and having an alicyclic structure or an aromatic ring with a halogenated alkyl group, n is 0 to 100, and m is 0 to 100, but when n=m=0, R 3 R 1 ). [6] The resin composition for an optical waveguide substrate according to claim 5, wherein the monomers represented by R 4 and R 5 represented organic groups in the bismaleimide compound represented by the general formula (1) are any of the tetravalent organic groups represented by the following structural formulas (A-1) to (A-13): (wherein the bonds represented by the characters * in the structural formulas are bonded to the carbonyl carbon atoms forming a cyclic imide structure in the general formula (1)). [7] The resin composition for an optical waveguide substrate according to claim 5, wherein the groups represented by R 4 and R 5represented organic groups in the bismaleimide compound represented by the general formula (1) are any of the tetravalent organic groups represented by the following structural formulas (A-3) to (A-6) and (A-8) to (A-11), and the bismaleimide compound has a Hansen solubility parameter of a dispersion term δd of 16.6 MPa 1 / 2 or more and 21.2 MPa 1 / 2 or less, a polar term δp of 4.4 MPa 1 / 2 or more and 9.0 MPa 1 / 2 or less, and a hydrogen bond term δh of 4.4 MPa 1 / 2 or more and 9.2 MPa 1 / 2 or less:(wherein the bonds represented by the characters * in the structural formulas are bonded to the carbonyl carbon atoms forming a cyclic imide structure in the general formula (1)). [8] A resin film comprising the resin composition according to any one of claims 1 to 7. [9] A cured product of the resin composition according to any one of claims 1 to 7. [10] An optical circuit board comprising the cured product according to claim 9.