Prepreg, laminate, printed wiring board, and semiconductor package

Abstract

Provided is a prepreg that exhibits high reflow heat resistance while maintaining low dielectric characteristics. Also provided are a laminate, a printed wiring board, and a semiconductor package, each of which includes the prepreg. Specifically, the prepreg contains a fibrous base material and a thermosetting resin composition containing a thermosetting resin (A) and a leveling agent (X) having an alkyl group with 1,000 to 100,000 carbon atoms.

Description

Prepreg, laminate, printed wiring board, and semiconductor package

[0001] The present disclosure relates to a prepreg, a laminate, a printed wiring board, and a semiconductor package.

[0002] In mobile communication devices typified by mobile phones, base station devices thereof, network infrastructure devices such as servers and routers, and large computers, the speed and capacity of signals used are increasing year by year. Along with this, printed wiring boards mounted on these electronic devices need to support high frequencies, and there is a need for a substrate material having a low relative permittivity and a low dielectric tangent (hereinafter, these may be collectively referred to as "low dielectric properties") in a high frequency band (for example, 10 GHz or higher) that enables reduction of transmission loss.

[0003] Examples of substrate materials having excellent low dielectric properties include (A) a modified polyphenylene ether having a carbon-carbon double bond at the terminal, (B) a modified isobutylene polymer having a carbon-carbon double bond at the terminal, (C) a styrene-based thermoplastic elastomer having a weight average molecular weight of 10,000 or more, and (D) a thermosetting resin composition containing a thermal radical initiator and a prepreg containing the thermosetting resin composition (see Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2023-141250

[0005] However, as a result of intensive studies by the present inventors, it has been found that printed wiring boards and semiconductor packages using a prepreg containing a component having low dielectric properties tend to have low reflow heat resistance.

[0006] In view of such a situation, an object of the present disclosure is to provide a prepreg that exhibits high reflow heat resistance while maintaining low dielectric properties, and to provide a laminate, a printed wiring board, and a semiconductor package using the prepreg.

[0007] As a result of diligent research, the present inventors have found that the resin composition of the present disclosure can achieve the above objective. The present disclosure includes the following embodiments [1] to

[14] . [1] A thermosetting resin composition containing a thermosetting resin (A) and a leveling agent (X) having an alkyl group having 1,000 to 100,000 carbon atoms, and a prepreg containing a fibrous substrate. [2] The prepreg according to [1], wherein the (X) component further has a carbonyl group. [3] The prepreg according to [1] or [2], wherein the (X) component is an acrylic resin-based leveling agent. [4] The prepreg according to any one of [1] to [3], wherein the content of the (X) component is 0.1 to 5% by mass with respect to the total amount of solids in the thermosetting resin composition. [5] The prepreg according to any one of [1] to [4], wherein the weight-average molecular weight of the (X) component is 3,000 to 100,000. [6] The prepreg according to any one of [1] to [5] above, wherein component (A) comprises one or more selected from the group consisting of epoxy resin, phenolic resin, maleimide resin, modified polyphenylene ether resin, cyanate resin, isocyanate resin, benzoxazine resin, oxetane resin, amino resin, unsaturated polyester resin, allyl resin, dicyclopentadiene resin, and silicone resin. [7] The prepreg according to any one of [1] to [6] above, further comprising elastomer (B). [8] The prepreg according to any one of [1] to [7] above, further comprising crosslinking agent (C). [9] The prepreg according to [8] above, wherein component (C) is a compound having a structure derived from a maleimide skeleton and a structure derived from butadiene.

[10] The prepreg according to any one of [1] to [9] above, further comprising inorganic filler (D).

[11] The prepreg according to any one of [1] to

[10] above, further comprising curing accelerator (E).

[12] A laminate having a cured prepreg according to any of [1] to

[11] above and a metal foil.

[13] A printed circuit board having a cured prepreg according to any of [1] to

[11] above.

[14] A semiconductor package having a printed circuit board according to

[13] above and a semiconductor element.

[0008] According to this disclosure, it is possible to provide a prepreg that exhibits high reflow heat resistance while maintaining low dielectric properties, and to provide laminates, printed wiring boards, and semiconductor packages using the prepreg.

[0009] In the numerical ranges described in this disclosure, the upper or lower limits of the numerical range may be replaced with the values ​​shown in the examples. Furthermore, the lower and upper limits of a numerical range may be arbitrarily combined with the lower or upper limits of other numerical ranges. In the notation "AA to BB" for a numerical range, the numbers AA and BB at both ends are included in the range as the lower and upper limits, respectively. In this disclosure, for example, "10 or more" means 10 and numbers greater than 10, and this applies even if the numbers are different. Similarly, for example, "10 or less" means 10 and numbers less than 10, and this applies even if the numbers are different. Furthermore, unless otherwise specified, each component and material exemplified in this disclosure may be used alone or in combination of two or more. In this disclosure, if there are multiple substances corresponding to each component in the resin composition, unless otherwise specified, the content of each component in the resin composition means the total amount of such multiple substances present in the resin composition.

[0010] In this disclosure, "resin components" refers to all components of the resin composition that constitute the solid content, excluding inorganic compounds such as inorganic fillers described later. In this disclosure, "solid content" refers to components other than organic solvents described later, and components that are liquid at 25°C are also considered to be solid content. The expression "contains XX" as described in this disclosure means that XX may be contained in a reacted state if XX is reactable, or it may simply mean that XX is contained. Any combination of the information described in this disclosure is also included in this disclosure and these embodiments.

[0011] [Prepreg] The prepreg of this embodiment is a prepreg comprising a thermosetting resin composition containing a thermosetting resin (A) and a leveling agent (X) having an alkyl group having 1,000 to 100,000 carbon atoms, and a fibrous substrate. By using the prepreg of this embodiment, the printed circuit board and semiconductor package of this embodiment exhibit high reflow heat resistance while maintaining low dielectric properties. The components that the prepreg of this embodiment may contain will be described in order below.

[0012] (Thermosetting resin (A)) Component (A) preferably contains one or more selected from the group consisting of epoxy resin, maleimide compound, modified polyphenylene ether resin, phenol resin, polyimide resin, cyanate resin, isocyanate resin, benzoxazine resin, oxetane resin, amino resin (e.g., melamine resin), unsaturated polyester resin, allyl resin, dicyclopentadiene resin, and silicone resin; more preferably contains one or more selected from the group consisting of epoxy resin, maleimide compound, modified polyphenylene ether resin, phenol resin, polyimide resin, cyanate resin, and isocyanate resin; even more preferably contains one or more selected from the group consisting of epoxy resin and maleimide compound; and particularly preferably contains a maleimide compound from the viewpoint of low thermal expansion. The modified polyphenylene ether resin is preferably a polyphenylene ether resin having ethylenically unsaturated bond-containing groups at its terminals; and more preferably a polyphenylene ether resin having ethylenically unsaturated bond-containing groups at both terminals. Examples of ethylenically unsaturated bond-containing groups include unsaturated aliphatic hydrocarbon groups such as vinyl groups, allyl groups, 1-methylallyl groups, isopropenyl groups, 2-butenyl groups, 3-butenyl groups, and styryl groups; and groups containing a heteroatom and an ethylenically unsaturated bond, such as maleimide groups and (meth)acryloyl groups. Component (A) may be used alone or in combination of two or more.

[0013] The epoxy resin is preferably an epoxy resin having two or more epoxy groups in one molecule. Here, epoxy resins are classified into glycidyl ether type epoxy resins, glycidyl amine type epoxy resins, glycidyl ester type epoxy resins, etc. Among these, glycidyl ether type epoxy resins are preferred. Epoxy resins are classified into various types based on differences in their main skeleton. Within each of the above types of epoxy resins, they are further classified into bisphenol-type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy resin; alicyclic epoxy resins such as dicyclopentadiene type epoxy resin; aliphatic chain epoxy resins; novolac-type epoxy resins such as phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, phenol aralkyl novolac type epoxy resin, and biphenyl aralkyl novolac type epoxy resin; stilbene type epoxy resin; naphthalene skeleton-containing epoxy resins such as naphthol novolac type epoxy resin and naphthol aralkyl type epoxy resin; biphenyl type epoxy resin; xylylene type epoxy resin; and dihydroanthracene type epoxy resin.

[0014] The maleimide compound preferably includes at least one selected from the group consisting of maleimide compounds and derivatives thereof having one or more (preferably two or more) N-substituted maleimide groups. The maleimide compound having one or more N-substituted maleimide groups is not particularly limited, but preferably aromatic maleimide compounds having one N-substituted maleimide group bonded to an aromatic ring, such as N-phenylmaleimide, N-(2-methylphenyl)maleimide, N-(4-methylphenyl)maleimide, N-(2,6-dimethylphenyl)maleimide, N-(2,6-diethylphenyl)maleimide, N-(2-methoxyphenyl)maleimide, N-benzylmaleimide; 4,4'-diphenylmethanebismaleimide, bis(4-maleimidophenyl) ether, bis(4-maleimidophenyl) sulfone, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide, 4-methyl- Examples include aromatic bismaleimide compounds having two N-substituted maleimide groups preferably bonded to an aromatic ring, such as 1,3-phenylenebismaleimide, m-phenylenebismaleimide, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, and indan ring-containing aromatic bismaleimide; aromatic polymaleimide compounds having three or more N-substituted maleimide groups preferably bonded to an aromatic ring, such as polyphenylmethanemaleimide and biphenylaralkyl-type maleimide; and aliphatic maleimide compounds such as N-dodecylmaleimide, N-isopropylmaleimide, and N-cyclohexylmaleimide, 1,6-bismaleimide-(2,2,4-trimethyl)hexane, and pyrophosphate binder-type long-chain alkylbismaleimide. Among these, aromatic bismaleimide compounds having two N-substituted maleimide groups bonded to an aromatic ring are more preferred from the viewpoint of compatibility with other resins, adhesion to conductors, heat resistance, low thermal expansion, mechanical properties, and low dielectric properties. 4,4'-diphenylmethanebismaleimide and indan ring-containing aromatic bismaleimide are even more preferred, and indan ring-containing aromatic bismaleimide is particularly preferred from the viewpoint of low dielectric properties (especially dielectric loss tangent (Df)).Furthermore, in the maleimide compound, it is preferable that the nitrogen atoms of the "preferably one N-substituted maleimide group bonded to the aromatic ring," the "preferably two N-substituted maleimide groups bonded to the aromatic ring," and the "preferably three or more N-substituted maleimide groups bonded to the aromatic ring" are all bonded to the aromatic ring. Thus, in the maleimide compound, it is preferable that the nitrogen atoms of the N-substituted maleimide groups are bonded to each other via a linking group that includes the aromatic ring.

[0015] Examples of derivatives of maleimide compounds include addition reaction products of a maleimide compound having one or more (preferably two or more) N-substituted maleimide groups with an amine compound such as a monoamine compound or a diamine compound. Examples of the monoamine compounds include monoamine compounds having acidic substituents such as o-aminophenol, m-aminophenol, p-aminophenol, o-aminobenzoic acid, m-aminobenzoic acid, p-aminobenzoic acid, o-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, 3,5-dihydroxyaniline, and 3,5-dicarboxyaniline. The diamine compounds include 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenylpropane, 2,2'-bis(4,4'-diaminodiphenyl)propane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylethane, 3,3'-diethyl-4,4'-diaminodiphenylethane, 4,4'-diaminodiphenyl ether, Examples include 4,4'-diaminodiphenylthioether, 3,3'-dihydroxy-4,4'-diaminodiphenylmethane, 2,2',6,6'-tetramethyl-4,4'-diaminodiphenylmethane, 3,3'-dichloro-4,4'-diaminodiphenylmethane, 3,3'-dibromo-4,4'-diaminodiphenylmethane, 2,2',6,6'-tetrachloro-4,4'-diaminodiphenylmethane, 2,2',6,6'-tetrabromo-4,4'-diaminodiphenylmethane, siloxanediamines, and the like.

[0016] (Content of component (A)) The content of component (A) in the thermosetting resin composition is not particularly limited, but from the viewpoint of heat resistance and moldability, it is preferably 1 to 95% by mass, more preferably 3 to 80% by mass, even more preferably 5 to 60% by mass, particularly preferably 10 to 55% by mass, and most preferably 20 to 50% by mass, relative to the total amount of solids in the thermosetting resin composition.

[0017] (Leveling agent (X) having an alkyl group having 1,000 to 100,000 carbon atoms) The thermosetting resin composition contained in the prepreg of this embodiment contains component (X), which provides excellent reflow heat resistance for printed circuit boards and semiconductor packages. The alkyl group of component (X) has 1,000 to 100,000 carbon atoms, but from the viewpoint of reflow heat resistance, the number of carbon atoms is preferably 1,000 to 50,000, more preferably 1,000 to 30,000, even more preferably 2,000 to 25,000, particularly preferably 3,500 to 23,000, and most preferably 5,000 to 20,000. In addition to the alkyl group, component (X) preferably further has a carbonyl group. The presence of a carbonyl group in component (X) tends to improve adhesion to metal foil. It is presumed that the effect of improving adhesion to metal is due to the increased electrostatic effect of the carbonyl group. Component (X) is preferably liquid at 25°C. The weight-average molecular weight (Mw) of component (X) is not particularly limited, but from the viewpoint of reflow heat resistance, it is preferably 3,000 to 100,000, more preferably 4,500 to 80,000, and even more preferably 5,000 to 60,000, and may also be 3,000 to 15,000, 3,000 to 12,000, 15,000 to 100,000, 20,000 to 80,000, or 30,000 to 60,000. In this disclosure, the weight-average molecular weight (Mw) is a value measured in polystyrene terms by gel permeation chromatography (GPC), and more specifically, a value measured by the method described in the examples.

[0018] From the viewpoint of reflow heat resistance, component (X) is preferably an acrylic resin-based leveling agent. From the viewpoint of reflow heat resistance, among acrylic resin-based leveling agents, it is preferable that it is an acrylic resin-based leveling agent that does not contain a siloxane skeleton. Here, the term "acrylic resin-based" means that it may contain not only structural units derived from acrylic acid esters, but also structural units derived from methacrylic acid esters, or structural units derived from other polymerizable compounds. In the term "acrylic resin-based," the content of structural units derived from acrylic acid esters is preferably 50 to 100% by mass, more preferably 80 to 100% by mass, and even more preferably 90 to 100% by mass. Examples of acrylic resin-based leveling agents include the Polyflow series manufactured by Kyoeisha Chemical Co., Ltd., the Disparon series manufactured by Kusumoto Kasei Co., Ltd., and the ARUFON UP-1000 series manufactured by Toagosei Chemical Co., Ltd.

[0019] Generally, leveling agents are used to reduce the surface tension difference across the entire surface of the paint, and are not used in the production of prepregs, especially printed circuit board prepregs, where surface tension differences are not a concern. In particular, acrylic resin-based leveling agents are not generally used in the production of prepregs, especially printed circuit board prepregs. However, in this embodiment, by including a leveling agent, preferably an acrylic resin-based leveling agent, in the prepreg, we succeeded in improving the "reflow heat resistance" which is unrelated to surface tension differences. It is presumed that component (X) is unevenly distributed near the surface of the prepreg and not evenly dispersed throughout the prepreg, but even so, an improvement in reflow heat resistance is obtained.

[0020] (Content of component (X)) The content of component (X) in the thermosetting resin composition is not particularly limited, but is preferably 0.1 to 5% by mass, more preferably 0.2 to 3% by mass, and even more preferably 0.3 to 2.5% by mass, relative to the total amount of solids in the thermosetting resin composition. When the content of component (X) is above the lower limit, the effect of improving reflow heat resistance tends to be greater. Also, when the content of component (X) is below the upper limit, the low dielectric properties tend to be easier to improve.

[0021] (Elastomer (B)) The thermosetting resin composition contained in the prepreg of this embodiment is not particularly limited, but from the viewpoint of low dielectric properties (especially dielectric loss tangent (Df)), it is preferable to contain elastomer (B). In this disclosure, elastomer is defined as a polymer compound that exhibits rubber elasticity at 25°C. The rubber elasticity is preferably such that the modulus of elasticity (Young's modulus) is 1 to 10 MPa. Examples of component (B) include styrene elastomers, olefin elastomers, urethane elastomers, polyester elastomers, polyamide elastomers, acrylic elastomers, silicone elastomers, etc. Component (B) may be used alone or two or more may be used in combination.

[0022] As for component (B), a styrene-based elastomer is preferred from the viewpoint of low dielectric properties (particularly dielectric loss tangent (Df)), and a styrene-based thermoplastic elastomer is more preferred. As for the styrene-based elastomer, it is sufficient to have structural units derived from a styrene-based compound, and from the viewpoint of dielectric loss tangent (Df), adhesion to conductors, heat resistance, and low thermal expansion, one or more selected from the group consisting of hydrogenated styrene-butadiene-styrene block copolymer (SEBS or SBBS), hydrogenated styrene-isoprene-styrene block copolymer (SEPS), and styrene-maleic anhydride copolymer (SMA) is preferred, one or more selected from the group consisting of hydrogenated styrene-butadiene-styrene block copolymer (SEBS) and hydrogenated styrene-isoprene-styrene block copolymer (SEPS) is more preferred, and hydrogenated styrene-butadiene-styrene block copolymer (SEBS) is even more preferred. Furthermore, the styrene elastomer (excluding SMA as described above) may be modified with an acid anhydride such as maleic anhydride. Examples include SEBS modified with an acid anhydride such as maleic anhydride, and SEPS modified with an acid anhydride such as maleic anhydride. The acid value of the acid-modified styrene elastomer (excluding SMA as described above) is not particularly limited, but is between 2 and 20 mgCH. ３ ONa / g is preferred, and 5 to 15 mg CH ３ ONa / g is more preferably 7-13 mgCH ３ ONa / g is even more preferred. Here, the acid value is sodium methoxide (CH ３ It can be measured by titration using ONa.

[0023] In component (B), the content of styrene-derived structural units [hereinafter sometimes referred to as "styrene content"] is not particularly limited, but from the viewpoint of dielectric loss tangent (Df), adhesion to conductors, heat resistance and low thermal expansion, it is preferably 5 to 80% by mass, more preferably 10 to 75% by mass, even more preferably 15 to 60% by mass, particularly preferably 18 to 45% by mass, most preferably 18 to 40% by mass, and may also be 5 to 30% by mass, 10 to 30% by mass, 25 to 60% by mass, or 25 to 45% by mass.

[0024] The number-average molecular weight (Mn) of component (B) is not particularly limited, but is preferably 12,000 to 1,000,000, more preferably 30,000 to 500,000, may be 50,000 to 200,000, may be 50,000 to 150,000, may be 50,000 to 100,000, and may be 60,000 to 90,000. In this disclosure, the number-average molecular weight (Mn) is a value measured in polystyrene terms by gel permeation chromatography (GPC), and more specifically, is a value measured by the method described in the examples.

[0025] (Content of component (B)) When the thermosetting resin composition contains component (B), the content of component (B) is not particularly limited, but is preferably 1 to 35% by mass, more preferably 3 to 30% by mass, even more preferably 5 to 25% by mass, and particularly preferably 5 to 20% by mass, relative to the total amount of solids in the thermosetting resin composition. When the content of component (B) is above the lower limit, a better dielectric loss tangent (Df) tends to be obtained, and when it is below the upper limit, good heat resistance, moldability, processability, and flame retardancy tend to be obtained.

[0026] (Crosslinking agent (C)) The thermosetting resin composition contained in the prepreg of this embodiment may further contain a crosslinking agent (C). The inclusion of a crosslinking agent (C) tends to improve the compatibility between component (A) and component (B). The crosslinking agent (C) is preferably a compound having a structure derived from a maleimide skeleton and a structure derived from butadiene, and more preferably a compound having a structure derived from an indane ring-containing maleimide resin and a structure derived from butadiene. Furthermore, the structure derived from the maleimide skeleton is preferably a structure derived from an indane ring-containing aromatic bismaleimide.

[0027] Compounds having a structure derived from a maleimide skeleton and a structure derived from butadiene can be produced by reacting a maleimide resin and butadiene in the presence of an organic peroxide. The organic peroxide is not particularly limited, but examples include benzoyl peroxide, dicumyl peroxide, methyl ethyl ketone peroxide, and t-butyl perbenzoate. The amount of organic peroxide used is preferably 0.1 to 10 parts by mass per 100 parts by mass of the total amount of the maleimide resin and butadiene.

[0028] The butadiene used in the production of a compound having a structure derived from a maleimide skeleton and a structure derived from butadiene is preferably 200 to 10,000 in number average molecular weight, more preferably 500 to 5,000, even more preferably 500 to 2,500, and particularly preferably 800 to 2,000.

[0029] (Content of component (C)) When the thermosetting resin composition contained in the prepreg of this embodiment contains component (C), the content of component (C) is not particularly limited, but is preferably 1 to 40% by mass, more preferably 2 to 35% by mass, even more preferably 3 to 30% by mass, and particularly preferably 4 to 25% by mass, relative to the total amount of solids in the thermosetting resin composition, and may also be 4 to 20% by mass, 4 to 15% by mass, or 4 to 10% by mass. If the content of component (C) is above the lower limit, the compatibility between component (A) and component (B) tends to be good, and if it is below the upper limit, it tends to be easier to maintain good heat resistance and flame retardancy.

[0030] (Inorganic Filler (D)) The thermosetting resin composition contained in the prepreg of this embodiment tends to have improved low thermal expansion, heat resistance and flame retardancy by further containing an inorganic filler (D). The (D) component is not particularly limited, but examples include silica, alumina, titanium oxide, mica, beryllium, barium titanate, potassium titanate, strontium titanate, calcium titanate, aluminum carbonate, magnesium hydroxide, aluminum hydroxide, aluminum silicate, calcium carbonate, calcium silicate, magnesium silicate, silicon nitride, boron nitride, clay (calcined clay, etc.), molybdate compounds (zinc molybdate, etc.), talc, aluminum borate, silicon carbide, etc. The (D) component may be used alone or two or more may be used in combination. Among these, silica, alumina, mica, and talc are preferred from the viewpoint of low thermal expansion, heat resistance and flame retardancy, silica and alumina are more preferred, and silica is even more preferred. Examples of silica include crushed silica, fumed silica, and fused silica (spherical fused silica).

[0031] The shape and particle size of component (D) are not particularly limited, but the particle size is preferably 0.01 to 20 μm, more preferably 0.1 to 10 μm, even more preferably 0.2 to 1 μm, and particularly preferably 0.3 to 0.8 μm. Here, particle size refers to the average particle diameter, which is the particle diameter at the point corresponding to 50% of the volume when the cumulative frequency distribution curve by particle diameter is determined with the total volume of particles set to 100%. The particle size of component (D) can be measured using a particle size distribution analyzer that uses laser diffraction scattering or the like.

[0032] (Content of component (D)) When the thermosetting resin composition contained in the prepreg of this embodiment contains component (D), the content of component (D) is not particularly limited, but from the viewpoint of low thermal expansion, heat resistance and flame retardancy, it is preferably 5 to 70% by volume, more preferably 15 to 60% by volume, even more preferably 20 to 55% by volume, and particularly preferably 25 to 50% by volume, relative to the total amount of solids in the resin composition.

[0033] Furthermore, component (D) may be an inorganic filler that has been pre-treated with a coupling agent by a dry or wet method, from the viewpoint of improving the dispersibility of component (D) and the adhesion between component (D) and the organic components in the resin composition. The coupling agent is not particularly limited, and for example, a silane coupling agent or a titanate coupling agent can be appropriately selected and used. One type of coupling agent may be used alone, or two or more types may be used in combination. Also, the amount of coupling agent used is not particularly limited.

[0034] In this embodiment, when component (D) is used, in order to improve the dispersibility of component (D) in the resin composition, it may be used as a slurry in which component (D) is pre-dispersed in an organic solvent, if necessary. Examples of organic solvents include those described later.

[0035] (Curing accelerator (E)) The thermosetting resin composition contained in the prepreg of this embodiment tends to have improved curability, resulting in better low dielectric properties, heat resistance, adhesion to conductors, elastic modulus, and glass transition temperature, by further containing a curing accelerator (E). When the resin composition of this embodiment contains a curing accelerator (E), a suitable curing accelerator (E) can be appropriately selected according to the type of thermosetting resin (B) component used. One type of curing accelerator (E) may be used alone, or two or more types may be used in combination.

[0036] (E) Component may include amine-based curing accelerators, imidazole-based curing accelerators, phosphorus-based curing accelerators, organometallic salts, acidic catalysts, organic peroxides, etc. In this embodiment, imidazole-based curing accelerators are not classified as amine-based curing accelerators. Examples of amine-based curing accelerators include amine compounds having primary to tertiary amines such as triethylamine, pyridine, tributylamine, dicyandiamide, and N-2-(aminoethyl)-3-aminopropyltrimethoxysilane; and quaternary ammonium compounds. Examples of imidazole-based curing accelerators include imidazole compounds such as methylimidazole, phenylimidazole, 2-undecylimidazole, and isocyanate-masquimidazole (for example, an addition reaction product of hexamethylene diisocyanate resin and 2-ethyl-4-methylimidazole). Examples of phosphorus-based curing accelerators include tertiary phosphines such as triphenylphosphine, and quaternary phosphonium compounds such as the tri-n-butylphosphine addition product of p-benzoquinone. Examples of organometallic salts include carboxylates of manganese, cobalt, zinc, etc. Examples of acidic catalysts include p-toluenesulfonic acid. Examples of organic peroxides include dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyn-3,2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, t-butylperoxyisopropyl monocarbonate, and α,α'-di(t-butylperoxy)diisopropylbenzene. Among these, imidazole-based curing accelerators are preferred from the viewpoint of obtaining better low dielectric properties, heat resistance, adhesion to conductors, elastic modulus, and glass transition temperature. Furthermore, an embodiment using an imidazole-based curing accelerator in combination with an organic peroxide is also preferred.

[0037] (Content of component (E)) When the thermosetting resin composition contained in the prepreg of this embodiment contains component (E), the content of component (E) is not particularly limited, but is preferably 0.001 to 10% by mass, more preferably 0.01 to 5% by mass, and even more preferably 0.05 to 3% by mass, relative to the total solid content of the thermosetting resin composition. When the content of component (E) is within the above range, there is a tendency for good low dielectric properties, heat resistance, storage stability, and moldability.

[0038] (Other Components) The thermosetting resin composition contained in the prepreg of this embodiment may further contain one or more optional components such as flame retardants, flame retardant aids, coupling agents, antioxidants, heat stabilizers, antistatic agents, ultraviolet absorbers, pigments, colorants, and lubricants, as needed. Alternatively, the thermosetting resin composition contained in the prepreg of this embodiment may not contain the aforementioned optional components. Each of the aforementioned optional components may be used individually or in combination of two or more.

[0039] If the thermosetting resin composition contained in the prepreg of this embodiment contains the above-mentioned optional components, the amount thereof is not particularly limited, but may be 0.01% by mass or more, 0.1% by mass or more, 0.5% by mass or more, 30% by mass or less, 10% by mass or less, 5% by mass or less, or 1% by mass or less, based on the total amount of resin components. Furthermore, the thermosetting resin composition contained in the prepreg of this embodiment may not contain the above-mentioned optional components, depending on the desired performance.

[0040] The thermosetting resin composition of this embodiment can be produced by mixing component (A) and component (X) and other components as needed in a known manner. In this case, each component may be dissolved or dispersed in the organic solvent while stirring. The mixing order, temperature, time, and other conditions are not particularly limited and can be set arbitrarily. Examples of the organic solvent include alcohol-based solvents such as ethanol, propanol, butanol, methyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether; ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ether-based solvents such as tetrahydrofuran; aromatic solvents such as toluene, xylene, and mesitylene; nitrogen-containing solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; sulfur-containing solvents such as dimethyl sulfoxide; and ester-based solvents such as γ-butyrolactone. These organic solvents may be used individually or in combination of two or more.

[0041] The prepreg of this embodiment is a prepreg comprising the thermosetting resin composition and a fibrous substrate, and more specifically, a prepreg comprising a semi-cured product of the thermosetting resin composition and a fibrous substrate. The fibrous substrate is preferably a sheet-like fibrous substrate. As the sheet-like fibrous substrate, known materials used in laminates for various electrical insulating materials can be used. Examples of materials for the sheet-like fibrous substrate include inorganic fibers such as E-glass, D-glass, S-glass, and Q-glass (quartz glass); organic fibers such as polyimide, polyester, and tetrafluoroethylene; and mixtures thereof. These sheet-like fibrous substrates have the shape of woven fabric, non-woven fabric, rawhide, chopped strand mat, or surfacing mat. The thickness of the sheet-like fibrous substrate is not particularly limited, but may be 1 to 100 μm, 3 to 70 μm, 5 to 55 μm, 15 to 55 μm, or 25 to 55 μm.

[0042] The prepreg of the present embodiment can be obtained by impregnating the thermosetting resin composition into a fiber base material and then heating and drying it to semi-cure (B-stage) it as necessary. More specifically, for example, the prepreg of the present embodiment can be produced by heating and drying it at 80 to 200°C for 1 to 30 minutes in a drying oven to semi-cure (B-stage) it. Here, in the present disclosure, B-staging means bringing it into the state of the B-stage defined in JIS K6900 (1994). The amount of the thermosetting resin composition used can be appropriately determined for the purpose of making the solid content concentration derived from the resin composition in the dried prepreg 30 to 90% by mass. By setting the solid content concentration within the above range, better moldability tends to be obtained when it is made into a laminate.

[0043] <Low dielectric characteristics> When the prepreg of the present embodiment is made into a test piece by the method described in the examples described later, the dielectric constant (Dk) at 10 GHz is not particularly limited, but is preferably 3.6 or less, more preferably 3.5 or less, and even more preferably 3.4 or less. The smaller the dielectric constant (Dk), the better, and the lower limit value is not particularly limited, but may be 2.5 or more, 3.0 or more, or 3.2 or more. That is, the dielectric constant (Dk) can be 2.5 to (此处原文有误,推测应为3.6)3.6. When the prepreg of the present embodiment is made into a test piece by the method described in the examples described later, the dielectric tangent (Df) at 10 GHz is not particularly limited, but is preferably 0.0025 or less, more preferably 0.0024 or less, even more preferably 0.0023 or less, and can also be 0.0022 or less. The smaller the dielectric tangent (Df), the better, and the lower limit value is not particularly limited, but may be 0.0015 or more, 0.0018 or more, or 0.0019 or more. That is, the dielectric tangent (Df) can be 0.0015 to 0.0025. The dielectric constant (Dk) and the dielectric tangent (Df) are values based on the cavity resonator perturbation method, and more specifically, are values measured by the method described in the examples. Also, in the present disclosure, when simply referring to the dielectric constant, it means the relative dielectric constant.

[0044] [Laminate] The laminate of this embodiment is a laminate having a cured prepreg of this embodiment and a metal foil. The laminate of this embodiment can be manufactured, for example, by placing the metal foil on one or both sides of a single prepreg of this embodiment, or by placing the metal foil on one or both sides of a laminate obtained by stacking two or more prepregs of this embodiment, and then by heating and pressing it. In the laminate obtained by this manufacturing method, the prepreg of this embodiment is C-staged. In this disclosure, C-staged means being in the state of C-stage as defined in JIS K6900 (1994). The laminate having the metal foil is sometimes called a metal-clad laminate. The metal of the metal foil is not particularly limited, but from the viewpoint of conductivity, it may be copper, gold, silver, nickel, platinum, molybdenum, ruthenium, aluminum, tungsten, iron, titanium, chromium, or an alloy containing one or more of these metal elements, with copper and aluminum being preferred, and copper being more preferred. The method for carrying out the aforementioned heat-pressure molding is not particularly limited, but for example, it can be carried out under conditions of a temperature of 100 to 300°C, a pressure of 0.2 to 10 MPa, and a time of 0.1 to 5 hours. In addition, the heat-pressure molding can be carried out by maintaining a vacuum state for 0.5 to 5 hours using a vacuum press or the like.

[0045] [Printed Wiring Board] The printed wiring board of this embodiment has either a cured prepreg of this embodiment or a laminate of this embodiment. The printed wiring board of this embodiment can be manufactured by using the laminate of this embodiment and performing circuit formation processing such as drilling, metal plating, and metal foil etching by known methods. Furthermore, a multilayer printed wiring board can be manufactured by performing multilayer bonding processing as needed. In the printed wiring board of this embodiment, the prepreg of this embodiment is C-staged.

[0046] [Semiconductor Package] The semiconductor package of the present embodiment is a semiconductor package having the printed wiring board of the present embodiment and a semiconductor element. The semiconductor package of the present embodiment can be manufactured by mounting semiconductor elements such as semiconductor chips and memories at predetermined positions on the printed wiring board of the present embodiment and then sealing them with a sealing material.

[0047] The prepreg, laminate, printed wiring board, and semiconductor package of the present embodiment can be suitably used in electronic devices that handle high-frequency signals of 10 GHz or higher. In particular, the printed wiring board is useful as a printed wiring board for a millimeter-wave radar.

[0048] As described above, the preferred embodiments have been described, but these are examples for the description of the present disclosure, and the scope of the present disclosure is not intended to be limited only to these embodiments. The present disclosure includes various aspects different from the above embodiments without departing from the gist thereof.

[0049] Hereinafter, the present embodiment will be described more specifically with reference to examples. However, the present disclosure is not limited to the following examples.

[0050] In each example, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) were measured by the following method. They were calculated from a calibration curve using standard polystyrene by gel permeation chromatography (GPC). The calibration curve was approximated by a cubic equation using standard polystyrene: TSK standard POLYSTYRENE (Type; A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40) [manufactured by Tosoh Corporation, trade name]. The GPC measurement conditions are shown below. Equipment: Pump: L-6200 [Hitachi High-Technologies Corporation] Detector: L-3300 RI [Hitachi High-Technologies Corporation] Column Oven: L-655A-52 [Hitachi High-Technologies Corporation] Column: Guard column; TSK Guardcolumn HHR-L + Column; TSKgel G4000HHR + TSKgel G2000HHR (all manufactured by Tosoh Corporation, product names) Column size: 6.0 × 40 mm (Guard column), 7.8 × 300 mm (column) Eluent: Tetrahydrofuran Sample concentration: 30 mg / 5 mL Injection volume: 20 μL Flow rate: 1.00 mL / min Measurement temperature: 40°C

[0051] [Production Example 1: Production of Maleimide-Modified Polybutadiene (Component (C))] 33.8 parts by mass of polybutadiene (1,2-polybutadiene homopolymer, number average molecular weight (Mn) = 1,200, vinyl group content = 85 mol% or more), 1.43 parts by mass of the maleimide resin (A-1) described later, 0.0035 parts by mass of α,α'-bis(t-butylperoxy)diisopropylbenzene, and toluene as an organic solvent were added to a 2 L glass flask container capable of heating and cooling, equipped with a thermometer, reflux condenser, and stirring device. The mixture was then reacted under a nitrogen atmosphere at 90-100°C for 5 hours with stirring to obtain a solution of maleimide-modified polybutadiene (solid content concentration: 35% by mass). The number average molecular weight (Mn) of the obtained maleimide-modified polybutadiene was 2,000.

[0052] Furthermore, GPC was measured using the method described above for the solution containing the polybutadiene and the maleimide resin (A-1) before the reaction and for the solution after the reaction, and the peak area derived from the maleimide resin before and after the reaction was determined. Next, the vinyl group modification rate of the maleimide resin was calculated using the following formula. The vinyl group modification rate corresponds to the rate of decrease in the peak area derived from the maleimide resin due to the reaction. Vinyl group modification rate (%) = [(Peak area derived from maleimide resin before the reaction) - (Peak area derived from maleimide resin after the reaction)] × 100 / (Peak area derived from maleimide resin before the reaction) The vinyl group modification rate obtained from the above formula was 40%.

[0053] [Examples 1-5, Comparative Example 1] (Preparation of Thermosetting Resin Composition) Each component listed in Table 1 was stirred and mixed with toluene and methyl ethyl ketone at room temperature according to the formulation composition listed in Table 1 to prepare a thermosetting resin composition (resin varnish) with a solid content concentration of 55-65% by mass. Note that the values ​​listed in the formulation composition in Table 1 refer to parts by mass in terms of solid content in the case of a solution or dispersion. (Prepreg Production) The resin composition obtained above was coated onto a glass cloth with a thickness of 0.1 mm, and then heated and dried at 130°C for 5 minutes to produce a prepreg with a solid content concentration of approximately 50% by mass derived from the resin composition. (Production of Double-Sided Copper-Clad Laminate) Four of these prepregs were stacked, and 12 μm thick copper foil (Rz: 0.6 μm on the M side (matte side)) was placed above and below it so that the M side was in contact with the prepreg. This laminate was heated and pressure-molded under the conditions of 230°C, 3.0 MPa, and 90 minutes to produce a double-sided copper-clad laminate (thickness: 0.41 mm).

[0054] [Evaluation Method] Each measurement and evaluation was performed according to the method described below. The results are shown in Table 1. (1. Dielectric Properties) The outer copper foil of the double-sided copper-clad laminate obtained in each example was removed by immersion in a copper etching solution (10% by mass solution of ammonium persulfate, manufactured by Mitsubishi Gas Chemical Company, Inc.), and a specimen measuring 90 mm in length and 70 mm in width was cut out to serve as the test specimen. Using this test specimen, the dielectric constant (Dk) and dielectric loss tangent (Df) were measured under the conditions of a frequency of 10 GHz and a measurement temperature of 25°C using the cavity resonator perturbation method. The measuring instrument used was the vector network analyzer "N5227A" manufactured by Agilent Technologies, Inc., the cavity resonator used was the "CP129" (10 GHz band resonator) manufactured by Kanto Electronics Applied Development Co., Ltd., and the measurement program used was "CPMA-V2".

[0055] (2. Reflow Heat Resistance) The double-sided copper-clad laminates obtained in each example were cut into 5 cm squares and used as substrates for evaluating reflow heat resistance. Next, an air reflow system (model number: TAR30-366PN, manufactured by Tamura Corporation) was used as the reflow apparatus, with a feed rate of 0.61 m / min and the temperature inside the reflow apparatus set to a maximum of 260°C. The six reflow heat resistance evaluation substrates obtained above were passed through the reflow apparatus up to 20 times, and the number of passes until blistering occurred on the reflow heat resistance evaluation substrates was investigated. The number of passes was the average value of the six reflow heat resistance evaluation substrates. If no blistering occurred after 20 passes, it was indicated as "≧20".

[0056] (3. Adhesion strength to copper foil) The adhesion strength to copper foil was evaluated by measuring the load when the copper foil of the double-sided copper-clad laminate obtained in each example was partially etched to form a 1 mm wide copper foil line, and the copper foil line was peeled off at a speed of 50 mm / min in a direction 90° to the adhesive surface.

[0057]

[0058] The abbreviations for each material in Table 1 are as follows: [Component (A)] Maleimide resin (A-1): Bismaleimide resin containing an indan skeleton

[0059] [Component (X)] ・Acrylic resin leveling agent (X-1): "Polyflow No. 36" (Weight-average molecular weight (Mw) = 10,000, manufactured by Kyoeisha Chemical Co., Ltd.) ・Acrylic resin leveling agent (X-2): "Polyflow No. 56" (Weight-average molecular weight (Mw) = 6,000, manufactured by Kyoeisha Chemical Co., Ltd.) ・Acrylic resin leveling agent (X-3): "Polyflow No. 85HF" (Weight-average molecular weight (Mw) = 50,000, manufactured by Kyoeisha Chemical Co., Ltd.) [Component for comparison] ・Silane coupling agent (X'-4): 3-Isocyanatetopropyltriethoxysilane

[0060] [Component (B)] SEBS (B-1): SEBS "KRATON (registered trademark) MD1653", styrene content 31% by mass, number average molecular weight (Mn) = 72,100

[0061] [Component (C)] Crosslinking agent (C-1): Maleimide-modified polybutadiene obtained in Production Example 1

[0062] [Component (D)] Silica (D-1): Spherical fused silica, average particle size: 0.5 μm, 70% by mass slurry (solvent: methyl isobutyl ketone)

[0063] [Component (E)] • Curing accelerator (E-1): α,α'-di(t-butylperoxy)diisopropylbenzene • Curing accelerator (E-2): Isocyanate macuimidazole

[0064] In Comparative Example 1, the adhesion strength to copper foil was improved by using a silane coupling agent with functional groups in a material with low dielectric properties, and it was expected that this would improve reflow heat resistance. However, there is still room for improvement in the adhesion strength to copper foil, and reflow heat resistance could not be improved. On the other hand, in each example, the low dielectric properties were maintained, and the reflow heat resistance was superior to that of Comparative Example 1. Furthermore, it can be seen that the adhesion strength to copper foil was also higher in each example compared to Comparative Example 1.

Claims

1. A thermosetting resin composition containing a thermosetting resin (A) and a leveling agent (X) having an alkyl group having 1,000 to 100,000 carbon atoms, and a prepreg containing a fiber substrate.

2. The prepreg according to claim 1, wherein the (X) component further has a carbonyl group.

3. The prepreg according to claim 1, wherein the (X) component is an acrylic resin-based leveling agent.

4. The prepreg according to claim 1, wherein the content of component (X) is 0.1 to 5% by mass relative to the total amount of solids in the thermosetting resin composition.

5. The prepreg according to claim 1, wherein the weight-average molecular weight of component (X) is 3,000 to 100,000.

6. The prepreg according to claim 1, wherein component (A) comprises one or more selected from the group consisting of epoxy resin, phenolic resin, maleimide resin, modified polyphenylene ether resin, cyanate resin, isocyanate resin, benzoxazine resin, oxetane resin, amino resin, unsaturated polyester resin, allyl resin, dicyclopentadiene resin, and silicone resin.

7. The prepreg according to claim 1, further comprising elastomer (B).

8. The prepreg according to claim 1, further comprising a crosslinking agent (C).

9. The prepreg according to claim 8, wherein component (C) is a compound having a structure derived from a maleimide skeleton and a structure derived from butadiene.

10. The prepreg according to claim 1, further comprising an inorganic filler (D).

11. The prepreg according to claim 1, further comprising a curing accelerator (E).

12. A laminate having a cured prepreg according to claim 1 and a metal foil.

13. A printed circuit board having a cured prepreg according to claim 1.

14. A semiconductor package having a printed circuit board as described in claim 13 and a semiconductor element.

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