Resin material, cured product, and multilayer printed wiring board

Abstract

The present invention provides a resin material which is capable of suppressing delamination between an insulating layer and a metal layer and is capable of enhancing the thermal dimensional stability of a cured product thereof.　A resin material according to the present invention contains an epoxy compound (A), a curing agent (B), and a curing accelerator (C). The curing agent (B) contains an active ester compound. The curing accelerator (C) contains a phosphorus-containing compound that is in a liquid state at 25°C.

Description

Resin materials, cured products, and multilayer printed wiring boards

[0001] The present invention relates to a resin material containing an epoxy compound, a cured product of the resin material, and a multilayer printed wiring board using the resin material.

[0002] Conventionally, various resin materials have been used to obtain electronic components such as semiconductor devices, laminates, and printed wiring boards. For example, in multilayer printed wiring boards, resin materials are used to form insulating layers for insulating between internal layers and to form insulating layers located on the surface. Wiring, which is generally metal, is laminated on the surface of the insulating layer. Furthermore, film-like resin materials (resin films) are sometimes used to form the insulating layers. The resin materials are used as insulating materials for multilayer printed wiring boards, including build-up films.

[0003] Patent Document 1 below discloses a resin composition containing (A) a phosphorus-containing curing catalyst, (B) an epoxy resin, (C) an active ester compound, and (D) an inorganic filler. In this resin composition, the content of component (C) is 10% by mass or more, and the content of component (D) is 60% by mass or more, where the total nonvolatile components in the resin composition is 100% by mass.

[0004] Patent Document 2 listed below discloses a thermosetting resin composition containing an epoxy resin (A), an active ester curing agent (B), a phosphorus-based curing accelerator (C), and a pyridine compound (D) having a tertiary amino group.

[0005] JP 2022-109004 A JP 2019-157027 A

[0006] In recent years, in electronic components such as printed wiring boards, the surface roughness of metal layers (wiring layers) has been reduced in order to reduce dielectric loss associated with higher frequencies, which has led to increased susceptibility to peeling at the interface between the metal layer and the insulating layer (cured layer of a resin material) during the manufacture of electronic components.

[0007] Furthermore, resin materials containing active ester compounds are sometimes used to reduce the dielectric tangent of the cured product, but conventional resin materials containing active ester compounds are more likely to cause delamination between the insulating layer and the metal layer.

[0008] Furthermore, it is desirable that the resin material used as the material for the insulating layer has high thermal dimensional stability when cured.

[0009] However, with conventional resin materials such as those described in Patent Documents 1 and 2, it is difficult to achieve both suppression of interlayer delamination between the insulating layer and the metal layer and improvement of the thermal dimensional stability of the cured product.

[0010] An object of the present invention is to provide a resin material that can suppress delamination between an insulating layer and a metal layer and can improve the thermal dimensional stability of the cured product. Another object of the present invention is to provide a cured product of the resin material. A further object of the present invention is to provide a multilayer printed wiring board using the resin material.

[0011] This specification discloses the following resin material, cured product, and multilayer printed wiring board.

[0012] Item 1. A resin material comprising an epoxy compound (A), a curing agent (B), and a curing accelerator (C), wherein the curing agent (B) comprises an active ester compound, and the curing accelerator (C) comprises a phosphorus-containing compound that is liquid at 25°C.

[0013] Item 2. The resin material according to Item 1, wherein the content of the phosphorus-containing compound that is liquid at 25°C is 0.1 wt% or more and 5 wt% or less, based on 100 wt% of components in the resin material excluding the solvent.

[0014] Item 3. The resin material according to Item 1 or 2, wherein the viscosity of the phosphorus-containing compound that is liquid at 25°C is 100 Pa·s or less when measured using a Brookfield viscometer at 25°C.

[0015] Item 4. The resin material according to any one of Items 1 to 3, wherein the epoxy compound (A) includes an aliphatic epoxy compound having a glycidyl ether skeleton.

[0016] Item 5. The resin material according to any one of Items 1 to 4, wherein the curing accelerator (C) includes the phosphorus-containing compound that is liquid at 25°C and an amine compound that does not have an imidazole skeleton.

[0017] Item 6. The resin material according to any one of Items 1 to 5, further comprising an inorganic filler (D).

[0018] Item 7. The resin material according to Item 6, wherein the content of the inorganic filler (D) is 30% by weight or more based on 100% by weight of components excluding the solvent in the resin material.

[0019] Item 8. The resin material according to any one of Items 1 to 7, further comprising a thermoplastic resin (E).

[0020] Item 9. The resin material according to any one of Items 1 to 8, which is a resin film.

[0021] Item 10. The resin material according to any one of Items 1 to 9, which is used to form an insulating layer in a multilayer printed wiring board.

[0022] Item 11. A cured product of a resin material, wherein the resin material is the resin material according to any one of Items 1 to 10.

[0023] Item 12. A multilayer printed wiring board comprising a circuit board, a plurality of insulating layers disposed on a surface of the circuit board, and a metal layer disposed between the plurality of insulating layers, wherein at least one of the plurality of insulating layers is a cured product of the resin material according to any one of Items 1 to 10.

[0024] The resin material according to the present invention comprises an epoxy compound (A), a curing agent (B), and a curing accelerator (C), wherein the curing agent (B) comprises an active ester compound, and the curing accelerator (C) comprises a phosphorus-containing compound that is liquid at 25° C. Because the resin material according to the present invention has the above-described configuration, it is possible to suppress interlayer delamination between the insulating layer and the metal layer, and to enhance the thermal dimensional stability of the cured product.

[0025] FIG. 1 is a cross-sectional view schematically showing a multilayer printed wiring board using a resin material according to one embodiment of the present invention.

[0026] The present invention will be described in detail below.

[0027] (Resin Material) The resin material according to the present invention contains an epoxy compound (A), a curing agent (B), and a curing accelerator (C), wherein the curing agent (B) contains an active ester compound, and the curing accelerator (C) contains a phosphorus-containing compound that is liquid at 25°C.

[0028] The resin material according to the present invention has the above-described structure, and therefore can suppress delamination between the insulating layer and the metal layer, and can improve the thermal dimensional stability of the cured product.

[0029] The reason why the use of the resin material according to the present invention can suppress delamination between the insulating layer and the metal layer is presumed to be as follows: However, the following is only a presumption, and the reason why the use of the resin material according to the present invention can suppress delamination between the insulating layer and the metal layer is not limited to the following.

[0030] The resin material according to the present invention uses a phosphorus-containing compound (curing accelerator) that is liquid at 25°C. Because the phosphorus-containing compound is liquid at 25°C, it is easily dispersed uniformly throughout the resin material. This facilitates uniform and successful curing, resulting in a cured resin material with a uniform degree of cure. This suppresses delamination due to erosion of the roughening solution into the interface between the insulating layer and the metal layer. Furthermore, because the cured resin material has a uniform degree of cure, the linear expansion coefficient of the cured resin material can be reduced, thereby enhancing the thermal dimensional stability of the cured resin material.

[0031] In recent years, electronic components such as printed wiring boards have become increasingly finer with respect to wiring. To form finer wiring, a SAP process is sometimes included in the manufacturing process of electronic components. In the SAP process, a treatment is performed to roughen the surface of a metal layer (wiring layer) to improve adhesion between the metal layer and the insulating layer. Furthermore, in electronic components such as printed wiring boards, the surface roughness of the metal layer (wiring layer) is being reduced to reduce dielectric loss associated with higher frequencies. Therefore, during the manufacturing of electronic components, peeling is more likely to occur at the interface between the metal layer and the insulating layer (cured layer of a resin material). Furthermore, with conventional resin materials containing active ester compounds, peeling is even more likely to occur at the interface between the insulating layer and the metal layer.

[0032] In contrast, the resin material according to the present invention has the above-described configuration, and therefore, even if fine wiring is well formed on the surface of the insulating layer (cured layer of the resin material), delamination between the wiring layer (metal layer) and the insulating layer can be suppressed. The resin material according to the present invention can suppress delamination between the wiring layer (metal layer) and the insulating layer, despite containing an active ester compound.

[0033] Furthermore, since the resin material according to the present invention has the above-described configuration, the glass transition temperature of the cured product can be increased. As described above, the resin material according to the present invention can obtain a cured product of the resin material having a uniform degree of cure, and the glass transition temperature of the cured product can be increased.

[0034] Furthermore, since the resin material according to the present invention has the above-mentioned configuration, and in particular, since the resin material contains an active ester compound, the dielectric loss tangent of the cured product can be reduced.

[0035] The resin material according to the present invention may be a resin composition or a resin film. The resin composition has fluidity. The resin composition may be in a paste form. The paste form includes a liquid form. The resin material according to the present invention is preferably a resin film because it is easy to handle.

[0036] The resin material according to the present invention is preferably a thermosetting resin material. When the resin material is a resin film, the resin film is preferably a thermosetting resin film.

[0037] In the following description, "100% by weight of the components in the resin material excluding the solvent" means 100% by weight of the components in the resin material excluding the solvent if the resin material contains a solvent, and means 100% by weight of the resin material if the resin material does not contain a solvent. "100% by weight of the components in the resin material excluding the solvent" means 100% by weight of the non-volatile components in the resin material.

[0038] In the following description, "100% by weight of components in the resin material excluding the inorganic filler (D) and the solvent" means 100% by weight of components in the resin material excluding the inorganic filler (D) and the solvent when the resin material contains the inorganic filler (D) and the solvent. "100% by weight of components in the resin material excluding the inorganic filler (D) and the solvent" means 100% by weight of components in the resin material excluding the inorganic filler (D) when the resin material contains the inorganic filler (D) but not the solvent. "100% by weight of components in the resin material excluding the inorganic filler (D) and the solvent" means 100% by weight of components in the resin material excluding the solvent when the resin material does not contain the inorganic filler (D) but contains the solvent. "100% by weight of components in the resin material excluding the inorganic filler (D) and the solvent" means 100% by weight of non-volatile components in the resin material excluding the inorganic filler (D).

[0039] Hereinafter, details of each component used in the resin material according to the present invention and uses of the resin material according to the present invention will be described.

[0040] [Epoxy Compound (A)] The resin material contains an epoxy compound (A). As the epoxy compound (A), a conventionally known epoxy compound can be used. Only one type of epoxy compound (A) may be used, or two or more types may be used in combination.

[0041] Examples of the epoxy compound (A) include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy compounds, bisphenol E type epoxy compounds, phenol novolac type epoxy compounds, cresol novolac type epoxy compounds, biphenyl type epoxy compounds, biphenyl novolac type epoxy compounds, biphenol type epoxy compounds, naphthalene type epoxy compounds, fluorene type epoxy compounds, phenol aralkyl type epoxy compounds, naphthol aralkyl type epoxy compounds, dicyclopentadiene type epoxy compounds, anthracene type epoxy compounds, epoxy compounds having an adamantane skeleton, epoxy compounds having a tricyclodecane skeleton, naphthylene ether type epoxy compounds, and epoxy compounds having a triazine nucleus in the skeleton.

[0042] The epoxy compound (A) may be a glycidyl ether compound. The glycidyl ether compound is a compound having at least one glycidyl ether group.

[0043] The epoxy compound (A) preferably contains an aliphatic epoxy compound having a glycidyl ether skeleton, and more preferably contains an aliphatic epoxy compound having a glycidyl ether skeleton and an epoxy compound having an aromatic ring. In these cases, the effects of the present invention can be more effectively exhibited, and in particular, interlayer delamination between the insulating layer and the metal layer can be significantly effectively suppressed.

[0044] The epoxy compound having an aromatic ring is preferably an epoxy compound having a naphthalene skeleton or a phenyl skeleton. In this case, the dielectric tangent of the cured product can be further reduced. In addition, the thermal dimensional stability of the cured product can be further improved.

[0045] The aliphatic epoxy compound having a glycidyl ether skeleton may include an epoxy compound having one or two epoxy groups, may include an epoxy compound having three or more epoxy groups, or may include both an epoxy compound having one or two epoxy groups and an epoxy compound having three or more epoxy groups. The epoxy compound having an aromatic ring may include an epoxy compound having one or two epoxy groups, may include an epoxy compound having three or more epoxy groups, or may include both an epoxy compound having one or two epoxy groups and an epoxy compound having three or more epoxy groups.

[0046] The content of the aliphatic epoxy compound having a glycidyl ether skeleton in 100% by weight of the epoxy compound (A) is preferably 15% by weight or more, more preferably 18% by weight or more, and preferably 35% by weight or less, more preferably 30% by weight or less. When the content of the aliphatic epoxy compound having a glycidyl ether skeleton is equal to or more than the above lower limit and equal to or less than the above upper limit, delamination between the insulating layer and the metal layer can be more effectively suppressed.

[0047] The molecular weight of the epoxy compound (A) is preferably 1000 or less. When the molecular weight is equal to or less than the upper limit, a resin material having high fluidity during the formation of an insulating layer is easily obtained, and lamination properties can be improved. Furthermore, since lamination properties can be improved, the plating peel strength of the cured product can be further improved.

[0048] The molecular weight of the epoxy compound (A) means a molecular weight that can be calculated from the structural formula when the epoxy compound (A) is not a polymer and when the structural formula of the epoxy compound (A) can be identified. When the epoxy compound (A) is a polymer, the molecular weight means a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

[0049] The content of the epoxy compound (A) in the resin material, based on 100% by weight of the components excluding the solvent, is preferably 10% by weight or more, more preferably 15% by weight or more, and preferably 80% by weight or less, more preferably 70% by weight or less. When the content of the epoxy compound (A) is above the above lower limit and below the above upper limit, the dielectric tangent of the cured product can be further reduced. Furthermore, when the content of the epoxy compound (A) is above the above lower limit and below the above upper limit, interlayer delamination between the insulating layer and the metal layer can be more effectively suppressed. Furthermore, the thermal dimensional stability of the cured product can be further improved.

[0050] The content of the epoxy compound (A) in the resin material, based on 100% by weight of the components excluding the inorganic filler (D) and the solvent, is preferably 10% by weight or more, more preferably 40% by weight or more, preferably 80% by weight or less, more preferably 70% by weight or less, and even more preferably 60% by weight or less. When the content of the epoxy compound (A) is above the above lower limit and below the above upper limit, the dielectric tangent of the cured product can be further reduced. Furthermore, when the content of the epoxy compound (A) is above the above lower limit and below the above upper limit, interlayer delamination between the insulating layer and the metal layer can be more effectively suppressed. Furthermore, the thermal dimensional stability of the cured product can be further improved.

[0051] [Curing Agent (B)] The resin material contains a curing agent (B). The curing agent (B) may be used alone or in combination of two or more types.

[0052] Examples of the curing agent (B) include an active ester compound, a phenol compound, a cyanate ester compound, a benzoxazine compound, a carbodiimide compound, a thiol compound, a phosphine compound, dicyandiamide, and an acid anhydride. The curing agent (B) preferably has a functional group capable of reacting with the epoxy group of the epoxy compound (A).

[0053] The content of the curing agent (B) per 100 parts by weight of the epoxy compound (A) is preferably 30 parts by weight or more, more preferably 50 parts by weight or more, even more preferably 60 parts by weight or more, particularly preferably 70 parts by weight or more, most preferably 80 parts by weight or more, and preferably 150 parts by weight or less, more preferably 130 parts by weight or less. When the content of the curing agent (B) is above the above lower limit and below the above upper limit, the curing property can be improved and the volatilization of remaining unreacted components can be further suppressed. Furthermore, when the content of the curing agent (B) is above the above lower limit, the thermal dimensional stability of the cured product can be further improved.

[0054] The content of the curing agent (B) in the resin material (100% by weight, excluding the inorganic filler (D) and the solvent) is preferably 20% by weight or more, more preferably 25% by weight or more, even more preferably 27% by weight or more, and preferably 60% by weight or less, more preferably 50% by weight or less. When the content of the curing agent (B) is above the above lower limit and below the above upper limit, the curability can be improved and the volatilization of remaining unreacted components can be further suppressed. Furthermore, when the content of the curing agent (B) is above the above lower limit, the thermal dimensional stability of the cured product can be further improved.

[0055] <Active ester compound> In order to reduce the dielectric loss tangent of the cured product, the curing agent (B) contains an active ester compound. The active ester compounds may be used alone or in combination of two or more.

[0056] The active ester compound is a compound that contains at least one ester bond in its structure and has aromatic rings bonded to both sides of the ester bond. The active ester compound can be obtained, for example, by a condensation reaction between a carboxylic acid compound or a thiocarboxylic acid compound and a hydroxy compound or a thiol compound.

[0057] Examples of the active ester compound include compounds represented by the following formula (1):

[0058]

[0059] In the above formula (1), X1 represents a group containing an aliphatic chain, a group containing an aliphatic ring, or a group containing an aromatic ring, and X2 represents a group containing an aromatic ring. Preferred examples of the group containing an aromatic ring include an optionally substituted benzene ring and an optionally substituted naphthalene ring. Examples of the substituent include a hydrocarbon group. The number of carbon atoms in the hydrocarbon group is preferably 12 or less, more preferably 6 or less, and even more preferably 4 or less.

[0060] Examples of combinations of X1 and X2 include a combination of an optionally substituted benzene ring and an optionally substituted benzene ring, and a combination of an optionally substituted benzene ring and an optionally substituted naphthalene ring.Furthermore, examples of combinations of X1 and X2 include a combination of an optionally substituted naphthalene ring and an optionally substituted naphthalene ring.

[0061] The active ester compound is not particularly limited. From the viewpoint of further improving the thermal dimensional stability and flame retardancy of the cured product, the active ester compound is preferably an active ester compound having two or more aromatic skeletons. From the viewpoint of lowering the dielectric tangent of the cured product and improving the thermal dimensional stability of the cured product, the active ester compound more preferably has a naphthalene ring in the skeleton of the main chain.

[0062] Commercially available products of the active ester compound include "HPC-8000-65T," "HPC-8000L-65MT," "HPC-8150-60T," "HPC-8150-62T," "EXB9416-70BK," and "EXB8100-65T," manufactured by DIC Corporation.

[0063] The content of the active ester compound in 100% by weight of the curing agent (B) may be 60% by weight or more, 70% by weight or more, 80% by weight or more, 90% by weight or more, 95% by weight or more, or even 100% by weight. The content of the active ester compound in 100% by weight of the curing agent (B) may be 100% by weight or less, less than 100% by weight, or 95% by weight or less.

[0064] The content of the active ester compound per 100 parts by weight of the epoxy compound (A) is preferably 30 parts by weight or more, more preferably 50 parts by weight or more, even more preferably 60 parts by weight or more, particularly preferably 70 parts by weight or more, preferably 150 parts by weight or less, more preferably 130 parts by weight or less. When the content of the active ester compound is above the above lower limit and below the above upper limit, curability can be improved and volatilization of remaining unreacted components can be further suppressed. Furthermore, when the content of the active ester compound is above the above lower limit and below the above upper limit, the dielectric tangent of the cured product can be further reduced. Furthermore, when the content of the active ester compound is above the above lower limit, the thermal dimensional stability of the cured product can be further improved.

[0065] The content of the active ester compound in the resin material (100% by weight, excluding the inorganic filler (D) and the solvent) is preferably 20% by weight or more, more preferably 25% by weight or more, even more preferably 30% by weight or more, particularly preferably 40% by weight or more, preferably 60% by weight or less, and more preferably 50% by weight or less. When the content of the active ester compound is above the lower limit and below the upper limit, curability can be improved and volatilization of remaining unreacted components can be further suppressed. Furthermore, when the content of the active ester compound is above the lower limit and below the upper limit, the dielectric tangent of the cured product can be further reduced. Furthermore, when the content of the active ester compound is above the lower limit, the thermal dimensional stability of the cured product can be further improved.

[0066] <Phenol Compound> Examples of the phenol compound include novolac type phenols, biphenol type phenols, naphthalene type phenols, dicyclopentadiene type phenols, aralkyl type phenols, dicyclopentadiene type phenols, etc. The phenol compounds may be used alone or in combination of two or more.

[0067] Commercially available phenol compounds include novolac phenol (manufactured by DIC Corporation under the name "TD-2091"), biphenyl novolac phenol (manufactured by Meiwa Chemical Industry Co., Ltd. under the name "MEH-7851"), aralkyl phenol compounds (manufactured by Meiwa Chemical Industry Co., Ltd. under the name "MEH-7800"), and phenols having an aminotriazine skeleton (manufactured by DIC Corporation under the names "LA1356" and "LA3018-50P").

[0068] <Cyanate Ester Compound> Examples of the cyanate ester compound include novolac cyanate ester resins, bisphenol cyanate ester resins, and prepolymers of these partially trimerized resins. Examples of the novolac cyanate ester resins include phenol novolac cyanate ester resins and alkylphenol cyanate ester resins. Examples of the bisphenol cyanate ester resins include bisphenol A cyanate ester resins, bisphenol E cyanate ester resins, and tetramethylbisphenol F cyanate ester resins. The cyanate ester compounds may be used alone or in combination of two or more.

[0069] Commercially available cyanate ester compounds include phenol novolac cyanate ester resins (PT-30 and PT-60 manufactured by Lonza Japan) and trimerized prepolymers of bisphenol cyanate ester resins (BA-230S, BA-3000S, BTP-1000S, and BTP-6020S manufactured by Lonza Japan).

[0070] <Acid Anhydride> Examples of the acid anhydride include tetrahydrophthalic anhydride, alkylstyrene-maleic anhydride copolymer, etc. The acid anhydrides may be used alone or in combination of two or more.

[0071] Commercially available products of the above acid anhydrides include "Rikacid TDA-100" manufactured by New Japan Chemical Co., Ltd.

[0072] <Benzoxazine Compound> Examples of the benzoxazine compound include Pd-type benzoxazine, Fa-type benzoxazine, etc. The benzoxazine compound may be used alone or in combination of two or more types.

[0073] Commercially available products of the above benzoxazine compounds include "Pd type" manufactured by Shikoku Chemical Industry Co., Ltd.

[0074] <Carbodiimide Compound> The carbodiimide compound is a compound having a structural unit represented by the following formula (2). In the following formula (2), the right end and the left end are bonding sites to other groups. The carbodiimide compound may be used alone or in combination of two or more types.

[0075]

[0076] In the above formula (2), X represents an alkylene group, a group in which a substituent is bonded to an alkylene group, a cycloalkylene group, a group in which a substituent is bonded to a cycloalkylene group, an arylene group, or a group in which a substituent is bonded to an arylene group, and p represents an integer of 1 to 5. When a plurality of Xs are present, the plurality of Xs may be the same or different.

[0077] In one preferred embodiment, at least one X is an alkylene group, a group in which a substituent is bonded to an alkylene group, a cycloalkylene group, or a group in which a substituent is bonded to a cycloalkylene group.

[0078] Commercially available examples of the carbodiimide compound include "Carbodilite V-02B," "Carbodilite V-03," "Carbodilite V-04K," "Carbodilite V-07," "Carbodilite V-09," "Carbodilite 10M-SP," and "Carbodilite 10M-SP (modified)," all manufactured by Nisshinbo Chemical Inc., as well as "Stavaxol P," "Stavaxol P400," and "Hykasil 510," all manufactured by Rhein Chemie.

[0079] [Curing Accelerator (C)] The resin material contains a curing accelerator (C). The curing accelerator (C) may be used alone or in combination of two or more kinds.

[0080] Examples of the curing accelerator (C) include phosphorus-containing compounds (phosphorus-containing compounds that are liquid at 25°C and phosphorus-containing compounds that are solid at 25°C), amine compounds that do not have an imidazole skeleton, imidazole compounds, organometallic compounds, peroxides, and azo compounds.

[0081] The content of the curing accelerator (C) in the resin material, based on 100% by weight of the components excluding the solvent, is preferably 0.01% by weight or more, more preferably 0.05% by weight or more, even more preferably 0.1% by weight or more, particularly preferably 0.13% by weight or more, most preferably 0.22% by weight or more, and preferably 5% by weight or less, more preferably 2% by weight or less, even more preferably 1.5% by weight or less, particularly preferably 1% by weight or less, and most preferably 0.9% by weight or less. When the content of the curing accelerator (C) is above the above-mentioned lower limit and below the above-mentioned upper limit, the crosslinked structure in the cured product becomes uniform and the number of unreacted functional groups decreases, resulting in a high crosslink density. Furthermore, the resin material can be cured well even at relatively low temperatures. Furthermore, when the content of the curing accelerator is above the above-mentioned lower limit, the thermal dimensional stability of the cured product can be further improved. When the content of the curing accelerator (C) is below the above-mentioned upper limit, interlayer delamination between the insulating layer and the metal layer can be more effectively suppressed.

[0082] <Phosphorus-containing compound that is liquid at 25° C.> From the viewpoint of exerting the effects of the present invention, the curing accelerator (C) contains a phosphorus-containing compound that is liquid at 25° C. Furthermore, when the curing accelerator (C) contains a phosphorus-containing compound that is liquid at 25° C., the glass transition temperature of the cured product can be further increased. The above-mentioned phosphorus-containing compounds that are liquid at 25° C. may be used alone or in combination of two or more.

[0083] The phosphorus-containing compound means a compound containing a phosphorus atom.

[0084] Examples of the phosphorus-containing compound that is liquid at 25° C. include methyltributylphosphonium dimethylphosphate and tetrabutylphosphonium o,o-diethylphosphorodithioate.

[0085] The phrase "liquid at 25°C" in the phosphorus-containing compound that is liquid at 25°C means that the viscosity measured at 25°C using a Brookfield viscometer is 500 Pa·s or less.

[0086] The viscosity of the liquid phosphorus-containing compound at 25°C, as measured using a Brookfield viscometer at 25°C, is preferably 0.001 Pa·s or more, more preferably 0.01 Pa·s or more, preferably 100 Pa·s or less, more preferably 50 Pa·s or less, even more preferably 10 Pa·s or less, and particularly preferably 1.0 Pa·s or less. When the viscosity of the liquid phosphorus-containing compound at 25°C is equal to or greater than the lower limit, the liquid phosphorus-containing compound at 25°C is more easily dispersed uniformly in the resin material, thereby more effectively achieving the effects of the present invention. Furthermore, when the viscosity of the liquid phosphorus-containing compound at 25°C is equal to or greater than the lower limit and equal to or less than the upper limit, the glass transition temperature of the cured product can be further increased. Furthermore, when the viscosity of the liquid phosphorus-containing compound at 25°C is equal to or less than the upper limit, the thermal dimensional stability of the cured product can be further improved.

[0087] More specifically, the viscosity of the phosphorus-containing compound that is liquid at 25°C can be measured using a Brookfield viscometer (for example, "TVE33H" manufactured by Oyo Giken Co., Ltd.) under conditions of 25°C and 20 rpm.

[0088] The content of the phosphorus-containing compound that is liquid at 25°C in 100% by weight of the curing accelerator (C) may be 40% by weight or more, 50% by weight or more, 60% by weight or more, 70% by weight or more, 80% by weight or more, 90% by weight or more, or even 100% by weight. The content of the phosphorus-containing compound that is liquid at 25°C in 100% by weight of the curing accelerator (C) may be 100% by weight or less, less than 100% by weight, 90% by weight or less, 80% by weight or less, or 70% by weight or less.

[0089] The content of the phosphorus-containing compound liquid at 25°C, based on 100% by weight of the components in the resin material excluding the solvent, is preferably 0.1% by weight or more, more preferably greater than 0.1% by weight, even more preferably 0.12% by weight or more, particularly preferably 0.15% by weight or more, preferably 5% by weight or less, more preferably 2% by weight or less, even more preferably 1% by weight or less, and particularly preferably 0.8% by weight or less. When the content of the phosphorus-containing compound liquid at 25°C is equal to or greater than the above lower limit (or exceeds the above lower limit) and equal to or less than the above upper limit, the effects of the present invention can be more effectively exhibited. Furthermore, when the content of the phosphorus-containing compound liquid at 25°C is equal to or greater than the above lower limit (or exceeds the above lower limit) and equal to or less than the above upper limit, the glass transition temperature of the cured product can be further increased. Furthermore, when the content of the phosphorus-containing compound liquid at 25°C is equal to or greater than the above lower limit (or exceeds the above lower limit), the thermal dimensional stability of the cured product can be further improved. When the content of the phosphorus-containing compound liquid at 25°C is equal to or less than the above upper limit, interlayer delamination between the insulating layer and the metal layer can be more effectively suppressed.

[0090] <Amine Compounds Not Having an Imidazole Skeleton> Examples of the amine compounds not having an imidazole skeleton include diethylamine, triethylamine, diethylenetetramine, triethylenetetramine, diethylenetriamine, ethylenediamine, tris(dimethylaminomethyl)phenol, benzyldimethylamine, m-xylylenedi(dimethylamine), N,N'-dimethylpiperazine, N-methylpyrrolidine, N-methylhydroxypiperidine, m-xylylenediamine, isophoronediamine, N-aminoethylpiperazine, polyoxypropylenepolyamine, and 4,4-dimethylaminopyridine. The amine compounds not having an imidazole skeleton may be used alone or in combination of two or more.

[0091] The curing accelerator (C) preferably contains the above-mentioned amine compound having no imidazole skeleton. That is, the curing accelerator (C) preferably contains the above-mentioned phosphorus-containing compound that is liquid at 25° C. and the above-mentioned amine compound having no imidazole skeleton. In this case, the thermal dimensional stability and glass transition temperature of the cured product can be further increased.

[0092] The content of the amine compound not having an imidazole skeleton, based on 100% by weight of the components in the resin material excluding the solvent, is preferably 0.01% by weight or more, more preferably 0.05% by weight or more, even more preferably 0.1% by weight or more, and preferably 5% by weight or less, more preferably 2% by weight or less, and even more preferably 1% by weight or less. When the content of the amine compound not having an imidazole skeleton is equal to or more than the above lower limit and equal to or less than the above upper limit, the thermal dimensional stability and glass transition temperature of the cured product can be increased, and interlayer delamination between the insulating layer and the metal layer can be more effectively suppressed.

[0093] <Imidazole Compound> Examples of the imidazole compound include 2-undecylimidazole, 2-heptadecylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1,2-dimethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimellitate, and 1-cyanoethyl-2-phenylimidazolium trimethylolate. Examples of the imidazole compounds include limeritate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-methylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-dihydroxymethylimidazole. The imidazole compounds may be used alone or in combination of two or more.

[0094] <Organometallic Compound> Examples of the organometallic compound include zinc naphthenate, cobalt naphthenate, tin octoate, cobalt octoate, bisacetylacetonate cobalt(II), trisacetylacetonate cobalt(III), etc. The organometallic compounds may be used alone or in combination of two or more.

[0095] <Peroxide> Examples of the peroxide include diacyl peroxide, peroxy ester, peroxydicarbonate, monoperoxycarbonate, peroxyketal, dialkyl peroxide, dibenzyl peroxide, dicumyl peroxide, hydroperoxide, and ketone peroxide. The peroxides may be used alone or in combination of two or more.

[0096] [Inorganic filler (D)] The resin material preferably contains an inorganic filler (D). By using the inorganic filler (D), the dielectric loss tangent of the cured product can be further reduced, and the thermal dimensional stability of the cured product can be further improved. Only one type of inorganic filler (D) may be used, or two or more types may be used in combination.

[0097] Examples of the inorganic filler (D) include silica, talc, clay, mica, hydrotalcite, alumina, magnesium oxide, aluminum hydroxide, aluminum nitride, and boron nitride.

[0098] The inorganic filler (D) is preferably silica or alumina, more preferably silica, and even more preferably fused silica. In this case, the adhesive strength between the insulating layer and the metal layer can be further increased, and finer wiring can be formed on the surface of the insulating layer. When the inorganic filler (D) is silica, the thermal dimensional stability of the cured product can also be further improved.

[0099] The average particle size of the inorganic filler (D) is preferably 10 nm or more, more preferably 50 nm or more, even more preferably 100 nm or more, and is preferably 5 μm or less, more preferably 3 μm or less, even more preferably 1 μm or less, particularly preferably 0.5 μm or less. When the average particle size of the inorganic filler (D) is not less than the above lower limit and not more than the above upper limit, the adhesive strength between the insulating layer and the metal layer can be further increased.

[0100] The median diameter (d50) at 50% is used as the average particle diameter of the inorganic filler (D). The average particle diameter can be measured using a laser diffraction / scattering particle size distribution analyzer.

[0101] The inorganic filler (D) is preferably spherical, and more preferably spherical silica. In this case, the surface roughness of the insulating layer is effectively reduced, and the adhesive strength between the insulating layer and the metal layer can be further increased. When the inorganic filler (D) is spherical, the aspect ratio of the inorganic filler (D) is preferably 1 or more, preferably 2 or less, more preferably 1.5 or less.

[0102] The inorganic filler (D) is preferably surface-treated, more preferably surface-treated with a coupling agent, and even more preferably surface-treated with a silane coupling agent. In this case, the surface roughness of the roughened cured product is further reduced, and the adhesive strength between the insulating layer and the metal layer is further increased. In addition, finer wiring is formed on the surface of the insulating layer, and inter-wiring insulation reliability and inter-layer insulation reliability can be imparted.

[0103] Examples of the coupling agent include a silane coupling agent, a titanium coupling agent, and an aluminum coupling agent, etc. Examples of the silane coupling agent include methacrylsilane, acrylsilane, aminosilane, imidazolesilane, vinylsilane, and epoxysilane.

[0104] The content of the inorganic filler (D) in the resin material (100% by weight, excluding the solvent) is preferably 30% by weight or more, more preferably 40% by weight or more, even more preferably 50% by weight or more, particularly preferably 60% by weight or more, most preferably 65% ​​by weight or more, preferably 90% by weight or less, more preferably 85% by weight or less, even more preferably 83% by weight or less, particularly preferably 80% by weight or less, and most preferably 78% by weight or less. When the content of the inorganic filler (D) is above the above lower limit and below the above upper limit, the surface roughness of the insulating layer is further reduced, and the adhesive strength between the insulating layer and the metal layer is further increased. Furthermore, finer wiring is formed on the surface of the insulating layer. Furthermore, this content of the inorganic filler (D) can reduce the linear expansion coefficient of the cured product and simultaneously improve smear removal properties. Furthermore, when the content of the inorganic filler (D) is above the above lower limit, the dielectric loss tangent of the cured product is effectively reduced.

[0105] The content of the inorganic filler (D) in the resin material, based on 100% by volume of components excluding the solvent, is preferably 30% by volume or more, more preferably 40% by volume or more, even more preferably 50% by volume or more, preferably 75% by volume or less, more preferably 73% by volume or less, and even more preferably 70% by volume or less. When the content of the inorganic filler (D) is above the lower limit and below the upper limit, the surface roughness of the insulating layer is further reduced, and the adhesive strength between the insulating layer and the metal layer is further increased. Furthermore, finer wiring is formed on the surface of the insulating layer. Furthermore, this content of the inorganic filler (D) can reduce the linear expansion coefficient of the cured product and simultaneously improve smear removal properties. Furthermore, when the content of the inorganic filler (D) is above the lower limit, the dielectric loss tangent of the cured product is effectively reduced.

[0106] [Thermoplastic resin (E)] The resin material preferably contains a thermoplastic resin (E). Examples of the thermoplastic resin (E) include polyvinyl acetal resin, polyimide resin, and phenoxy resin. Only one type of thermoplastic resin (E) may be used, or two or more types may be used in combination.

[0107] From the viewpoint of effectively lowering the dielectric loss tangent of the cured product and effectively improving the adhesion of metal wiring regardless of the curing environment, the thermoplastic resin (E) is preferably a polyimide resin or a phenoxy resin. The use of a polyimide resin or a phenoxy resin prevents the resin film from becoming less able to fill holes or irregularities in a circuit board and prevents the inorganic filler (D) from becoming non-uniform. Furthermore, the use of a polyimide resin or a phenoxy resin makes it possible to adjust the melt viscosity, thereby improving the dispersibility of the inorganic filler (D), and preventing the resin material or B-staged product from wetting and spreading to unintended areas during the curing process.

[0108] The polyimide resin is not particularly limited. Conventionally known polyimide resins can be used as the polyimide resin. Only one type of polyimide resin may be used, or two or more types may be used in combination.

[0109] From the viewpoint of improving solubility, the polyimide resin is preferably a polyimide resin which is a reaction product of tetracarboxylic dianhydride and dimer diamine.

[0110] Examples of the tetracarboxylic dianhydride include pyromellitic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenylsulfonetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3',4,4'-biphenylethertetracarboxylic dianhydride, 3,3',4,4'-dimethyldiphenylsilanetetracarboxylic dianhydride, 3,3',4,4'-tetraphenylsilanetetracarboxylic dianhydride, 1,2,3,4-furantetracarboxylic dianhydride, and 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylsulfone dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylpropane dianhydride, 3,3',4,4'-perfluoroisopropylidenediphthalic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, bis(phthalic acid)phenylphosphine oxide dianhydride, p-phenylene-bis(triphenylphthalic acid) dianhydride, m-phenylene-bis(triphenylphthalic acid) dianhydride, bis(triphenylphthalic acid)-4,4'-diphenylter dianhydride, and bis(triphenylphthalic acid)-4,4'-diphenylmethane dianhydride.

[0111] Examples of the dimer diamine include VERSAMINE 551 (trade name, manufactured by BASF Japan, 3,4-bis(1-aminoheptyl)-6-hexyl-5-(1-octenyl)cyclohexene), VERSAMINE 552 (trade name, manufactured by Cognix Japan, hydrogenated VERSAMINE 551), PRIAMINE 1075, and PRIAMINE 1074 (trade names, all manufactured by Croda Japan).

[0112] The polyimide resin may have an acid anhydride structure, a maleimide structure, or a citraconic acid structure at its terminal. In this case, the polyimide resin can be reacted with an epoxy compound (A). By reacting the polyimide resin with the epoxy compound (A), the thermal dimensional stability of the cured product can be improved.

[0113] The phenoxy resin is not particularly limited. Conventionally known phenoxy resins can be used as the phenoxy resin. The phenoxy resins may be used alone or in combination of two or more.

[0114] Examples of the phenoxy resin include phenoxy resins having a skeleton such as a bisphenol A skeleton, a bisphenol F skeleton, a bisphenol S skeleton, a biphenyl skeleton, a novolac skeleton, a naphthalene skeleton, and an imide skeleton.

[0115] Commercially available phenoxy resins include, for example, "YP50," "YP55," and "YP70" manufactured by Nippon Steel Chemical & Material Co., Ltd., and "1256B40," "4250," "4256H40," "4275," "YX6954BH30," and "YX8100BH30" manufactured by Mitsubishi Chemical Corporation.

[0116] From the viewpoint of obtaining a resin material having even better storage stability, the weight average molecular weight of the thermoplastic resin (E) is preferably 5,000 or more, more preferably 10,000 or more, and preferably 100,000 or less, more preferably 50,000 or less.

[0117] The weight average molecular weight of the thermoplastic resin (E) is a weight average molecular weight measured by gel permeation chromatography (GPC) and calculated as polystyrene.

[0118] The content of the thermoplastic resin (E) is not particularly limited. The content of the thermoplastic resin (E) is preferably 1% by weight or more, more preferably 5% by weight or more, even more preferably 10% by weight or more, preferably 30% by weight or less, and more preferably 25% by weight or less, based on 100% by weight of the components in the resin material excluding the inorganic filler (D) and the solvent. When the content of the thermoplastic resin (E) is above the lower limit and below the upper limit, the resin material has good embedding properties in holes or irregularities in the circuit board. When the content of the thermoplastic resin (E) is above the lower limit, the formation of the resin film becomes easier, and a better insulating layer can be obtained. When the content of the thermoplastic resin (E) is below the upper limit, the thermal dimensional stability of the cured product becomes even higher, and the linear expansion coefficient of the cured product becomes even smaller. When the content of the thermoplastic resin (E) is below the upper limit, the surface roughness of the insulating layer becomes even smaller, and the adhesive strength between the insulating layer and the metal layer becomes even higher.

[0119] [Solvent] The resin material contains or does not contain a solvent. The resin material may contain or may not contain a solvent. By using the solvent, the viscosity of the resin material can be controlled within a suitable range, and the coatability of the resin material can be improved. The solvent may also be used to obtain a slurry containing the inorganic filler (D). Only one type of the solvent may be used, or two or more types may be used in combination.

[0120] Examples of the solvent include acetone, methanol, ethanol, butanol, 2-propanol, 2-methoxyethanol, 2-ethoxyethanol, 1-methoxy-2-propanol, 2-acetoxy-1-methoxypropane, toluene, xylene, methyl ethyl ketone, N,N-dimethylformamide, methyl isobutyl ketone, N-methyl-pyrrolidone, n-hexane, cyclohexane, cyclohexanone, and naphtha, which is a mixture.

[0121] It is preferable that most of the solvent is removed when the resin composition is formed into a film. Therefore, the boiling point of the solvent is preferably 200°C or less, more preferably 180°C or less. The content of the solvent in the resin composition is not particularly limited. The content of the solvent can be appropriately changed taking into account the coatability of the resin composition, etc.

[0122] When the resin material is a B-stage film, the content of the solvent in 100% by weight of the B-stage film is preferably 1% by weight or more, more preferably 2% by weight or more, preferably 15% by weight or less, more preferably 10% by weight or less.

[0123] [Other Components] For the purpose of improving impact resistance, heat resistance, resin compatibility, workability, etc., the resin material may contain other components in addition to the above-mentioned components (epoxy compound (A), curing agent (B), curing accelerator (C), inorganic filler (D), thermoplastic resin (E), and solvent). Examples of the other components include thermosetting compounds other than epoxy compounds; organic fillers; leveling agents; flame retardants; coupling agents; colorants; antioxidants; ultraviolet degradation inhibitors; antifoaming agents; thickeners; thixotropy-imparting agents, etc. One type of the other components may be used alone, or two or more types may be used in combination.

[0124] Examples of the thermosetting compound different from the epoxy compound include maleimide compounds.

[0125] Examples of the coupling agent include a silane coupling agent, a titanium coupling agent, and an aluminum coupling agent, etc. Examples of the silane coupling agent include vinyl silane, amino silane, imidazole silane, and epoxy silane.

[0126] The resin material may or may not contain glass cloth. The resin material preferably does not contain glass cloth. The resin material preferably is not a prepreg.

[0127] (Resin film) A resin film (B-staged product / B-stage film) can be obtained by molding the above-mentioned resin composition into a film. The above-mentioned resin material is preferably a resin film. The resin film is preferably a B-stage film.

[0128] Examples of methods for forming a resin composition into a film to obtain a resin film include the following: an extrusion molding method in which a resin composition is melt-kneaded using an extruder, extruded, and then formed into a film using a T-die, circular die, or the like; a casting molding method in which a resin composition containing a solvent is cast into a film; and other conventionally known film forming methods. Extrusion molding and casting molding are preferred because they can be used to make thinner films. Films include sheets.

[0129] The resin composition is formed into a film and dried by heating, for example, at 50°C to 150°C for 1 minute to 10 minutes to the extent that curing by heat does not proceed too much, to obtain a resin film that is a B-stage film.

[0130] The film-like resin composition obtained by the drying process described above is called a B-stage film. The B-stage film is in a semi-cured state. The semi-cured product is not completely cured, and curing can continue.

[0131] The resin film does not have to be a prepreg. When the resin film is not a prepreg, migration does not occur along the glass cloth or the like. Furthermore, when the resin film is laminated or precured, irregularities due to the glass cloth do not occur on the surface.

[0132] The resin film can be used in the form of a laminated film comprising a metal foil or a base film and a resin film laminated on the surface of the metal foil or the base film. The metal foil is preferably a copper foil.

[0133] Examples of the substrate film of the laminated film include polyester resin films such as polyethylene terephthalate film and polybutylene terephthalate film, olefin resin films such as polyethylene film and polypropylene film, and polyimide resin films. The surface of the substrate film may be subjected to a release treatment, if necessary.

[0134] From the viewpoint of controlling the degree of cure of the resin film more uniformly, the thickness of the resin film is preferably 5 μm or more and preferably 200 μm or less. When the resin film is used as an insulating layer of a circuit, the thickness of the insulating layer formed by the resin film is preferably equal to or greater than the thickness of the conductor layer (metal layer) that forms the circuit. The thickness of the insulating layer is preferably 5 μm or more and preferably 200 μm or less.

[0135] (Other Details of Resin Material) The resin material can be used for various applications. For example, the resin material is suitably used to form a mold resin in which a semiconductor chip is embedded in a semiconductor device. The resin material is also suitably used as an alternative to liquid crystal polymer (LCP), a millimeter wave antenna, or a rewiring layer. The resin material is not limited to the above applications, and is suitably used for wiring formation applications in general.

[0136] The resin material is preferably used as an adhesive material. The resin material is preferably used as, for example, an adhesive material for power overlay packages, an adhesive material for printed wiring boards, an adhesive material for coverlays of flexible printed circuit boards, or an adhesive material for semiconductor bonding. The resin material is preferably an adhesive material.

[0137] The resin material is preferably used as an insulating material. The resin material is preferably used to form an insulating layer in a printed wiring board, and more preferably to form an insulating layer in a multilayer printed wiring board. The resin material is preferably an insulating material, and more preferably an interlayer insulating material. The insulating material may also serve as an adhesive material.

[0138] The cured product according to the present invention is a cured product of a resin material obtained by curing the resin material described above. The cured product according to the present invention is a cured product of a resin material, and the resin material is the resin material described above. The cured product according to the present invention can be obtained by curing the resin material described above. The heating conditions for the resin material when obtaining the cured product according to the present invention are not particularly limited, as long as the resin material is cured.

[0139] (Laminated structure and copper-clad laminate) A laminated structure can be obtained by laminating a lamination target member having a metal layer on one or both sides of the resin film. The laminated structure comprises a lamination target member having a metal layer on its surface and a resin film laminated on the surface of the metal layer, the resin film being the resin material described above. The method for laminating the resin film and the lamination target member is not particularly limited, and known methods can be used. For example, the resin film can be laminated onto the lamination target member using a device such as a parallel plate press or a roll laminator while applying pressure with or without heating.

[0140] The material of the metal layer is preferably copper.

[0141] The lamination target member having the metal layer on its surface may be a metal foil such as a copper foil.

[0142] The resin material is preferably used to obtain a copper-clad laminate. An example of the copper-clad laminate is a copper-clad laminate including a copper foil and a resin film laminated on one surface of the copper foil, the resin film being made of the resin material described above.

[0143] The thickness of the copper foil of the copper-clad laminate is not particularly limited. The thickness of the copper foil is preferably 1 μm or more and 100 μm or less. In addition, in order to increase the adhesive strength between the cured resin material and the copper foil, the copper foil preferably has fine irregularities on its surface. The method for forming the irregularities is not particularly limited. Examples of the method for forming the irregularities include a method using a known chemical solution, a known plasma treatment, and a known UV treatment.

[0144] (Circuit board with insulating layer) The resin material is suitably used to obtain a circuit board with an insulating layer. An example of the circuit board with an insulating layer includes a circuit board and an insulating layer disposed on the surface of the circuit board, the insulating layer being a cured product of the resin material described above.

[0145] In the circuit board with an insulating layer, the insulating layer is preferably laminated on the surface of the circuit board on which the circuits are provided, and a portion of the insulating layer is preferably embedded between the circuits.

[0146] The above-mentioned circuit board with an insulating layer can be obtained by a conventionally known method.

[0147] (Multilayer substrate and multilayer printed wiring board) The resin material is suitably used to obtain a multilayer substrate. An example of the multilayer substrate is a multilayer substrate including a circuit board and an insulating layer laminated on the circuit board. The insulating layer of the multilayer substrate is a cured product of the resin material described above. The insulating layer is preferably laminated on the surface of the circuit board on which the circuits (metal layer) are provided. A portion of the insulating layer is preferably embedded between the circuits.

[0148] In the multilayer substrate, the surface of the insulating layer opposite to the surface on which the circuit board is laminated is preferably roughened.

[0149] The roughening treatment method is not particularly limited and may be any conventionally known roughening treatment method. The surface of the insulating layer may be subjected to swelling treatment before the roughening treatment.

[0150] Preferably, the multilayer substrate further comprises a copper plating layer laminated on the roughened surface of the insulating layer.

[0151] Another example of the multilayer substrate is a multilayer substrate comprising a circuit board, an insulating layer laminated on the surface of the circuit board, and copper foil laminated on the surface of the insulating layer opposite to the surface on which the circuit board is laminated. Preferably, the insulating layer is formed by using a copper-clad laminate comprising copper foil and a resin film laminated on one surface of the copper foil and curing the resin film. Furthermore, the copper foil is preferably etched to form a copper circuit.

[0152] Another example of the multilayer substrate is a multilayer substrate including a circuit board and a plurality of insulating layers laminated on a surface of the circuit board, at least one of the insulating layers disposed on the circuit board being formed using the resin material, and preferably the multilayer substrate further includes a circuit laminated on at least one surface of the insulating layer formed using the resin film.

[0153] The above resin material is suitably used to form an insulating layer in a multilayer printed wiring board.

[0154] The multilayer printed wiring board includes, for example, a circuit board, a plurality of insulating layers disposed on a surface of the circuit board, and a metal layer disposed between the plurality of insulating layers, and at least one of the insulating layers is a cured product of the resin material described above.

[0155] FIG. 1 is a cross-sectional view schematically showing a multilayer printed wiring board using a resin material according to one embodiment of the present invention.

[0156] In the multilayer printed wiring board 11 shown in FIG. 1, a plurality of insulating layers 13-16 are laminated on the upper surface 12a of a circuit board 12. The insulating layers 13-16 are cured layers. A metal layer 17 is formed on a partial region of the upper surface 12a of the circuit board 12. Of the plurality of insulating layers 13-16, the insulating layers 13-15 other than the insulating layer 16 located on the outer surface opposite the circuit board 12 have the metal layer 17 formed on a partial region of the upper surface. The metal layer 17 is a circuit. The metal layer 17 is disposed between the circuit board 12 and the insulating layer 13, and between each of the laminated insulating layers 13-16. The lower metal layer 17 and the upper metal layer 17 are connected to each other by at least one of via hole connections and through-hole connections (not shown).

[0157] In the multilayer printed wiring board 11, the insulating layers 13 to 16 are formed from a cured product of the resin material. In this embodiment, the surfaces of the insulating layers 13 to 16 are roughened, and thus fine holes (not shown) are formed in the surfaces of the insulating layers 13 to 16. The metal layer 17 extends into the fine holes. In addition, in the multilayer printed wiring board 11, the width dimension (L) of the metal layer 17 and the width dimension (S) of the portion where the metal layer 17 is not formed can be reduced. In addition, in the multilayer printed wiring board 11, good insulation reliability is provided between the upper metal layer and the lower metal layer that are not connected by via hole connections or through hole connections (not shown).

[0158] The present invention will be specifically described below by way of examples and comparative examples, but the present invention is not limited to the following examples.

[0159] The following materials were prepared:

[0160] (Epoxy compound (A)) Biphenyl type epoxy compound ("NC-3000" manufactured by Nippon Kayaku Co., Ltd.) Phenolic glycidyl ether type epoxy compound ("EX-201-IM" manufactured by Nagase & Co., Ltd.) Alcoholic glycidyl ether type epoxy compound ("PB3600" manufactured by Daicel Corporation, an aliphatic epoxy compound having a glycidyl ether skeleton) Alcoholic glycidyl ether type epoxy compound ("EX-216L" manufactured by Nagase & Co., Ltd., an aliphatic epoxy compound having a glycidyl ether skeleton)

[0161] (Curing agent (B)) Active ester compound-containing liquid (DIC Corporation's "HPC-8000L-65MT", solid content 65% by weight) Active ester compound-containing liquid (DIC Corporation's "HPC-8150-62T", solid content 62% by weight) Cyanate compound (Lonza Japan's "BA-3000S")

[0162] (Curing accelerator (C)) Phosphorus-containing compound that is liquid at 25°C ("PX-4MP" manufactured by Nippon Chemical Industry Co., Ltd., methyl tributyl phosphonium dimethyl phosphate, viscosity at 25°C: 0.66 Pa·s) Phosphorus-containing compound that is liquid at 25°C ("PX-4ET" manufactured by Nippon Chemical Industry Co., Ltd., tetrabutyl phosphonium o,o-diethyl phosphorodithioate, viscosity at 25°C: 1.29 Pa·s) Phosphorus-containing compound that is solid at 25°C ("DPCP" manufactured by Hokko Chemical Industry Co., Ltd., diphenylcyclopropenone) Phosphorus-containing compound that is solid at 25°C ("TPTP" manufactured by Hokko Chemical Industry Co., Ltd., tri-p-tolylphosphine) Phosphorus-containing compound that is solid at 25°C ("TPP" manufactured by Hokko Chemical Industry Co., Ltd., triphenylphosphine) Dimethylaminopyridine ("DMAP" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) 2-phenyl-4-methylimidazole ("2P4MZ" manufactured by Shikoku Chemicals Corporation)

[0163] (Inorganic filler (D)) Silica-containing slurry (75% by weight of silica: "SC4050-HOA" manufactured by Admatechs Co., Ltd., average particle size 1.0 μm, aminosilane treatment, cyclohexanone 25% by weight)

[0164] (Thermoplastic resin (E)) Phenoxy resin ("YX6954BH30" manufactured by Mitsubishi Chemical Corporation) Polyimide resin (a polyimide resin which is a reaction product of tetracarboxylic dianhydride and dimer diamine, synthesized according to Synthesis Example 1 below)

[0165] Synthesis Example 1 300.0 g of tetracarboxylic dianhydride ("BisDA-1000" manufactured by SABIC Japan LLC) and 665.5 g of cyclohexanone were placed in a reaction vessel equipped with a stirrer, a water divider, a thermometer, and a nitrogen gas inlet tube, and the solution in the reaction vessel was heated to 60 ° C. Next, 89.0 g of dimer diamine ("PRIAMINE 1075" manufactured by Croda Japan) and 54.7 g of 1,3-bisaminomethylcyclohexane (manufactured by Mitsubishi Gas Chemical Company, Inc.) were added dropwise to the reaction vessel. Next, 121.0 g of methylcyclohexane and 423.5 g of ethylene glycol dimethyl ether were added to the reaction vessel, and the imidization reaction was carried out at 140 ° C. for 10 hours. In this way, a polyimide resin-containing solution (non-volatile content 26.8 wt%) was obtained. The molecular weight (weight average molecular weight) of the obtained polyimide resin was 20,000. The molar ratio of acid component to amine component was 1.04.

[0166] The molecular weight of the polyimide resin was determined as follows.

[0167] GPC (gel permeation chromatography) measurement: Using a high-performance liquid chromatograph system manufactured by Shimadzu Corporation, measurements were performed at a column temperature of 40 ° C. and a flow rate of 1.0 ml / min using tetrahydrofuran (THF) as a developing solvent. An "SPD-10A" was used as a detector, and two "KF-804L" columns (exclusion limit molecular weight 400,000) manufactured by Shodex were used in series. Tosoh Corporation's "TSK Standard Polystyrene" was used as the standard polystyrene, and a calibration curve was created using substances with weight average molecular weights Mw = 354,000, 189,000, 98,900, 37,200, 17,100, 9,830, 5,870, 2,500, 1,050, and 500, and the molecular weight was calculated.

[0168] (Other) Dicyandiamide

[0169] (Examples 1 to 10 and Comparative Examples 1 to 10) The components shown in Tables 1 to 4 below were mixed in the amounts (unit: parts by weight of solid content) shown in Tables 1 to 4 below, and stirred at room temperature until a uniform solution was obtained, thereby obtaining a resin material.

[0170] Preparation of resin film: Using an applicator, the obtained resin material was applied to the release-treated surface of a release-treated polyethylene terephthalate film (PET film, "XG284" manufactured by Toray Industries, Inc., thickness 25 μm), and then dried for 2 minutes and 30 seconds in a gear oven at 100° C. to volatilize the solvent. In this way, a laminated film (a laminated film of PET film and resin film) was obtained in which a 40 μm-thick resin film (B-stage film) was laminated on the PET film.

[0171] (Evaluation) (1) Delamination The obtained resin film was laminated onto a metal layer (copper layer) to obtain a laminate of a resin film and a metal layer. Lamination was performed using a "batch vacuum laminator MVLP-500-IIA" manufactured by Meiki Seisakusho Co., Ltd., by reducing the pressure for 30 seconds to 13 hPa or less, laminating at 100 ° C and a pressure of 0.7 MPa for 30 seconds, and then pressing at 100 ° C and a pressure of 0.8 MPa for 60 seconds. This laminate was heated at 130 ° C for 30 minutes, then heated at 160 ° C for 30 minutes, and further heated at 110 ° C for 30 minutes to produce a substrate comprising an insulating layer and a metal layer. The interface between the insulating layer and the metal layer in the obtained substrate was observed using FIB-SEM, and the distance at which delamination occurred was measured.

[0172] [Criteria for evaluation of delamination] 〇〇: The maximum length of the delaminated portion is 1 μm or less. ○: The maximum length of the delaminated portion is more than 1 μm and 3 μm or less. △: The maximum length of the delaminated portion is more than 3 μm and 10 μm or less. ×: The maximum length of the delaminated portion is more than 10 μm.

[0173] (2) Thermal Dimensional Stability (Average Coefficient of Linear Expansion (CTE)) The resulting 40 μm thick resin film (B-stage film) was heated at 100°C for 30 minutes, then at 180°C for 30 minutes, and further at 200°C for 90 minutes to obtain a cured product. The resulting cured product was cut into a size of 3 mm x 25 mm. Using a thermomechanical analyzer ("EXSTAR TMA / SS6100" manufactured by SII NanoTechnology Inc.), the average coefficient of linear expansion (ppm / °C) of the cut cured product from 25°C to 150°C was calculated under conditions of a tensile load of 33 mN and a heating rate of 5°C / min.

[0174] [Criteria for determining the average linear expansion coefficient] ○○: The average linear expansion coefficient is 28 ppm / °C or less. ○: The average linear expansion coefficient is more than 28 ppm / °C and 30 ppm / °C or less. ×: The average linear expansion coefficient is more than 30 ppm / °C.

[0175] (3) Glass Transition Temperature The resulting 40 μm thick resin film (B-stage film) was heated at 100°C for 30 minutes, then at 180°C for 30 minutes, and then at 200°C for 90 minutes to obtain a cured product. The resulting cured product was cut into a size of 5 mm x 50 mm. Measurements were performed using a thermomechanical analyzer ("DMS6100" manufactured by SII NanoTechnology Inc.) under the following conditions: chuck distance 20 mm, amplitude 10 μm, initial tension amplitude 400 mN, temperature increase rate of 5°C / min from 50°C to 330°C, and frequency 10 Hz. The peak temperature of the loss tangent in the obtained measurement results was taken as the glass transition temperature Tg (°C).

[0176] (4) Dielectric Loss Tangent (Df) The resulting 40 μm thick resin film (B-stage film) was heated at 100° C. for 30 minutes, then at 180° C. for 30 minutes, and further at 200° C. for 90 minutes to obtain a cured product. The resulting cured product was cut into a size of 2 mm wide and 80 mm long, and 10 sheets were stacked together. The dielectric loss tangent was measured at room temperature (23° C.) and a frequency of 5.8 GHz by the cavity resonance method using a "Cavity Resonance Perturbation Dielectric Constant Measuring Apparatus CP521" manufactured by Kanto Electronics Application Development Co., Ltd. and a "Network Analyzer N5224A PNA" manufactured by Keysight Technologies, Inc.

[0177] [Evaluation criteria for dielectric loss tangent (Df)] ◯: Dielectric loss tangent is 5.0 × 10 －３ Less than ×: Dielectric loss tangent is 5.0 × 10 －３ exceed

[0178] The compositions and results are shown in Tables 1 to 4 below.

[0179]

[0180]

[0181]

[0182]

[0183] 11... Multilayer printed wiring board 12... Circuit board 12a... Upper surface 13 to 16... Insulating layers 17... Metal layer

Claims

1. A resin material comprising an epoxy compound (A), a curing agent (B), and a curing accelerator (C), wherein the curing agent (B) comprises an active ester compound, and the curing accelerator (C) comprises a phosphorus-containing compound that is liquid at 25°C.

2. The resin material according to claim 1, wherein the content of the phosphorus-containing compound that is liquid at 25°C is 0.1% by weight or more and 5% by weight or less, based on 100% by weight of the components in the resin material excluding the solvent.

3. The resin material according to claim 1 or 2, wherein the viscosity of the phosphorus-containing compound that is liquid at 25°C when measured using a Brookfield viscometer at 25°C is 100 Pa·s or less.

4. The resin material according to any one of claims 1 to 3, wherein the epoxy compound (A) comprises an aliphatic epoxy compound having a glycidyl ether skeleton.

5. The resin material according to any one of claims 1 to 4, wherein the curing accelerator (C) comprises the phosphorus-containing compound that is liquid at 25°C and an amine compound that does not have an imidazole skeleton.

6. The resin material according to any one of claims 1 to 5, further comprising an inorganic filler (D).

7. The resin material according to claim 6, wherein the content of said inorganic filler (D) is 30% by weight or more based on 100% by weight of the components excluding the solvent in the resin material.

8. The resin material according to any one of claims 1 to 7, further comprising a thermoplastic resin (E).

9. The resin material according to any one of claims 1 to 8, which is a resin film.

10. The resin material according to any one of claims 1 to 9, which is used to form an insulating layer in a multilayer printed wiring board.

11. A cured product of a resin material, wherein the resin material is the resin material according to any one of claims 1 to 10.

12. A multilayer printed wiring board comprising: a circuit board; a plurality of insulating layers arranged on the surface of said circuit board; and a metal layer arranged between said plurality of insulating layers, wherein at least one of said plurality of insulating layers is a cured product of the resin material described in any one of claims 1 to 10.

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