JP7120220B2 - Prepreg and its manufacturing method, laminated board, printed wiring board and semiconductor package - Google Patents

Description

The present invention relates to a prepreg and its manufacturing method, a laminate, a printed wiring board and a semiconductor package.

In recent years, the miniaturization, weight reduction, and multi-functionality of electronic equipment have progressed further, and along with this, LSI (Large Scale Integration), chip components, etc. have become highly integrated, and their forms have become multi-pin and miniaturized. is changing rapidly. For this reason, in order to improve the packaging density of electronic components, the development of finer wiring in multilayer printed wiring boards is underway. As a method of manufacturing a multilayer printed wiring board that meets these requirements, for example, prepreg or the like is used as an insulating layer, and only necessary portions are connected by via holes formed by, for example, laser irradiation (hereinafter also referred to as "laser vias"). However, a build-up type multilayer printed wiring board that forms wiring layers is becoming mainstream as a method suitable for weight reduction, miniaturization, and fine wiring.

In multilayer printed wiring boards, it is important to have high electrical connection reliability between multiple layers of wiring patterns formed with a fine wiring pitch and excellent high frequency characteristics.In addition, high connection reliability with semiconductor chips is important. sex is required. In particular, in recent years, motherboards for multi-functional mobile phone terminals and the like have become thinner and the density of wiring has increased remarkably, and laser vias used for interlayer connection are required to have a smaller diameter.
The dimensional stability of the substrate is one of the important characteristics when making interlayer connections with small-diameter laser vias. In multilayer wiring, each substrate is subjected to multiple times of heat and stress during lamination. Therefore, if there is a large variation in the dimensions of the substrate itself, especially in the amount of variation in the dimensions of each substrate due to thermal history, etc., the laser vias will be misaligned each time they are stacked, causing defects such as reduced connection reliability. obtain. For this reason, there is a demand for a substrate with small variations in the amount of dimensional change.

For example, in Patent Document 1, for the purpose of improving the matching between layers in a multilayer printed wiring board, a core comprising a base material having a first surface and a second surface containing a pre-cured thermosetting resin and having a first surface and a second surface , a prepreg characterized by comprising a first adhesive layer and a second adhesive layer respectively formed on the first and second surfaces of the core.

JP-A-2002-103494

However, the prepreg of Patent Literature 1 contains a thermosetting resin that has been cured in advance as a core, and thus has a problem of poor wiring embedding properties. In addition, the prepreg of Patent Document 1 requires a complicated production process because it requires a plurality of layers with different degrees of curing, and a prepreg with less variation in the amount of dimensional change obtained by a simpler method is desired. there is

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a prepreg having excellent moldability and small dimensional variation, a method for producing the same, a laminate, a printed wiring board, and a semiconductor package.

The inventors of the present invention have made intensive studies to achieve the above object, and as a result, found that a prepreg manufactured through a process of applying a specific heat treatment has excellent moldability and small variation in dimensional change. , have completed the present invention. The present invention relates to the following [1] to [10].
[1] A prepreg obtained through the following steps 1 to 3.
Step 1: A step of obtaining a prepreg precursor, wherein the prepreg precursor is obtained by B-staging a thermosetting resin composition, and the B-staging includes impregnating a base material with the thermosetting resin composition. After that, heat treatment is performed.
Step 2: A step of cooling the prepreg precursor obtained in Step 1.
Step 3: A step of obtaining a prepreg. The prepreg is obtained by subjecting the prepreg precursor cooled in step 2 to a surface heat treatment, and the surface heat treatment raises the surface temperature of the prepreg precursor. processing.
[2] The prepreg according to [1] above, wherein the surface heating treatment in step 3 is a treatment for raising the surface temperature of the prepreg precursor by 5 to 110°C.
[3] The prepreg according to [1] or [2] above, wherein the surface heating treatment in step 3 is a treatment of heating the surface temperature of the prepreg precursor to 20 to 130°C.
[4] The prepreg according to any one of [1] to [3] above, wherein the surface heat treatment in step 3 is a treatment of heating the prepreg precursor in an environment of 200 to 700°C.
[5] The prepreg according to any one of [1] to [4] above, wherein the heating time of the surface heat treatment in step 3 is 1.0 to 10.0 seconds.
[6] The prepreg according to any one of [1] to [5] above, wherein the base material is glass cloth.
[7] A laminate obtained by laminating and molding the prepreg according to any one of [1] to [6] above and a metal foil.
[8] A printed wiring board comprising the prepreg according to any one of [1] to [6] above or the laminate according to [7] above.
[9] A semiconductor package using the printed wiring board according to [8] above.
[10] A method for producing a prepreg according to any one of [1] to [6] above, which method comprises the following steps 1 to 3.
Step 1: A step of obtaining a prepreg precursor, wherein the prepreg precursor is obtained by B-staging a thermosetting resin composition, and the B-staging includes impregnating a base material with the thermosetting resin composition. After that, heat treatment is performed.
Step 2: A step of cooling the prepreg precursor obtained in Step 1.
Step 3: A step of obtaining a prepreg. The prepreg is obtained by subjecting the prepreg precursor cooled in step 2 to a surface heat treatment, and the surface heat treatment raises the surface temperature of the prepreg precursor. processing.

ADVANTAGE OF THE INVENTION According to this invention, the prepreg which is excellent in moldability and has small dimensional variation, its manufacturing method, a laminated board, a printed wiring board, and a semiconductor package can be provided.

FIG. 3 is a schematic diagram of an evaluation substrate used for measuring variation in dimensional change in Examples.

In this specification, the lower and upper limits of numerical ranges are arbitrarily combined with the lower and upper limits of other numerical ranges, respectively. Embodiments in which the items described in this specification are combined arbitrarily are also included in the present invention.

[Prepreg]
The prepreg of the present invention is a prepreg obtained through the following steps 1 to 3.
Step 1: A step of obtaining a prepreg precursor, wherein the prepreg precursor is obtained by B-staging a thermosetting resin composition, and the B-staging includes impregnating a base material with the thermosetting resin composition. After that, heat treatment is performed.
Step 2: A step of cooling the prepreg precursor obtained in Step 1.
Step 3: A step of obtaining a prepreg. The prepreg is obtained by subjecting the prepreg precursor cooled in step 2 to a surface heat treatment, and the surface heat treatment raises the surface temperature of the prepreg precursor. processing.
First, the base material and the thermosetting resin composition used for the prepreg of the present invention will be described, and then the method for producing the prepreg of the present invention will be described.
In the present invention, the B-stage refers to a semi-cured state of the thermosetting resin composition.

<Base material>
The base material that the prepreg of the present invention contains is not particularly limited and may be, for example, a well-known base material used for various laminates for electrical insulating materials.
Examples of the substrate include natural fibers such as paper and cotton linter; inorganic fibers such as glass fiber and asbestos; organic fibers such as aramid, polyimide, polyvinyl alcohol, polyester, tetrafluoroethylene and acrylic; and mixtures thereof. Among these, glass fiber is preferred. Glass fabric (glass cloth) is preferable as the glass fiber base material. Examples thereof include a mixture of fibers and cellulose fibers. More preferably, it is a woven glass fabric using E glass.
These substrates are in the form of woven fabrics, non-woven fabrics, roving, chopped strand mats, surfacing mats, and the like. The material and shape are selected according to the intended use and performance of the molded product, and one type may be used alone, or two or more types of materials and shapes may be combined as necessary.
The thickness of the substrate is, for example, 0.01 to 0.5 mm, preferably 0.015 to 0.2 mm, more preferably 0.02 to 0.1 mm, from the viewpoint of enabling moldability and high-density wiring. more preferred. From the viewpoint of heat resistance, moisture resistance, processability, etc., these substrates are preferably surface-treated with a silane coupling agent or the like, or mechanically fiber-opened.

<Thermosetting resin composition>
The thermosetting resin composition containing the prepreg of the present invention can be, for example, a thermosetting resin composition containing a known thermosetting resin used for prepregs for printed wiring boards. Not limited.
The thermosetting resin composition contains (A) a thermosetting resin, and is further selected from the group consisting of (B) a curing agent, (C) a curing accelerator and (D) an inorganic filler. It preferably contains at least one species, and more preferably contains (B) a curing agent, (C) a curing accelerator and (D) an inorganic filler.
Each component that the thermosetting resin composition may contain will be described below.

((A) thermosetting resin)
(A) The thermosetting resin is not particularly limited, and can be appropriately selected and used from those conventionally used as thermosetting resins.
(A) Thermosetting resins include epoxy resins, phenolic resins, maleimide compounds, cyanate resins, isocyanate resins, benzoxazine resins, oxetane resins, amino resins, unsaturated polyester resins, allyl resins, dicyclopentadiene resins, and silicone resins. , triazine resins, melamine resins, and the like. Among these, epoxy resins and maleimide compounds are preferred from the viewpoint of moldability and electrical insulation.
(A) The thermosetting resin may be used alone or in combination of two or more.

The epoxy equivalent of the epoxy resin is preferably 100-500 g/eq, more preferably 150-400 g/eq, and even more preferably 200-350 g/eq. Here, the epoxy equivalent is the mass (g/eq) of the resin per epoxy group, and can be measured according to the method specified in JIS K7236.

Examples of epoxy resins include glycidyl ether type epoxy resins, glycidyl amine type epoxy resins, glycidyl ester type epoxy resins, and the like. Among these, glycidyl ether type epoxy resins are preferred.
Epoxy resins are classified into various epoxy resins depending on the difference in the main skeleton, and in each of the above types of epoxy resins, bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, etc. Epoxy resin; biphenyl aralkyl novolak type epoxy resin, phenol novolak type epoxy resin, alkylphenol novolak type epoxy resin, cresol novolak type epoxy resin, naphthol alkylphenol copolymer novolac type epoxy resin, naphthol aralkyl cresol copolymer novolac type epoxy resin, bisphenol A novolak type epoxy resin, novolac type epoxy resin such as bisphenol F novolac type epoxy resin; stilbene type epoxy resin; triazine skeleton-containing epoxy resin; fluorene skeleton-containing epoxy resin; naphthalene type epoxy resin; anthracene type epoxy resin; biphenyl type epoxy resins; xylylene type epoxy resins; and alicyclic epoxy resins such as dicyclopentadiene type epoxy resins.
Among these, from the viewpoint of moldability and insulation reliability, novolac epoxy resins are preferred, and biphenylaralkyl novolak epoxy resins are more preferred.

As the maleimide compound, a maleimide compound (a1) having an N-substituted maleimide group (hereinafter also referred to as “maleimide compound (a1)”) is preferred.
Specific examples of the maleimide compound (a1) include, for example, N,N'-ethylenebismaleimide, N,N'-hexamethylenebismaleimide, bis(4-maleimidocyclohexyl)methane, 1,4-bis(maleimide Maleimides containing aliphatic hydrocarbon groups such as methyl)cyclohexane; N,N'-(1,3-phenylene)bismaleimide, N,N'-[1,3-(2-methylphenylene)]bismaleimide, N, N'-[1,3-(4-methylphenylene)]bismaleimide, N,N'-(1,4-phenylene)bismaleimide, bis(4-maleimidophenyl)methane, bis(3-methyl-4- maleimidophenyl)methane, 3,3′-dimethyl-5,5′-diethyl-4,4′-diphenylmethanebismaleimide, bis(4-maleimidophenyl)ether, bis(4-maleimidophenyl)sulfone, bis(4- Maleimidophenyl)sulfide, Bis(4-maleimidophenyl)ketone, 1,4-bis(4-maleimidophenyl)cyclohexane, 1,4-bis(maleimidomethyl)cyclohexane, 1,3-bis(4-maleimidophenoxy)benzene , 1,3-bis(3-maleimidophenoxy)benzene, bis[4-(3-maleimidophenoxy)phenyl]methane, bis[4-(4-maleimidophenoxy)phenyl]methane, 1,1-bis[4- (3-maleimidophenoxy)phenyl]ethane, 1,1-bis[4-(4-maleimidophenoxy)phenyl]ethane, 1,2-bis[4-(3-maleimidophenoxy)phenyl]ethane, 1,2- bis[4-(4-maleimidophenoxy)phenyl]ethane, 2,2-bis[4-(3-maleimidophenoxy)phenyl]propane, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, 2,2-bis[4-(3-maleimidophenoxy)phenyl]butane, 2,2-bis[4-(4-maleimidophenoxy)phenyl]butane, 2,2-bis[4-(3-maleimidophenoxy) Phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[4-(4-maleimidophenoxy)phenyl]-1,1,1,3,3,3-hexafluoro Propane, 4,4-bis(3-maleimidophenoxy)biphenyl, 4,4-bis(4-maleimidophenoxy)biphenyl, bis[4-(3-maleimidophenoxy)phenyl]ke ton, bis[4-(4-maleimidophenoxy)phenyl]ketone, 2,2′-bis(4-maleimidophenyl)disulfide, bis(4-maleimidophenyl)disulfide, bis[4-(3-maleimidophenoxy)phenyl ] sulfide, bis[4-(4-maleimidophenoxy)phenyl]sulfide, bis[4-(3-maleimidophenoxy)phenyl]sulfoxide, bis[4-(4-maleimidophenoxy)phenyl]sulfoxide, bis[4-( 3-maleimidophenoxy)phenyl]sulfone, bis[4-(4-maleimidophenoxy)phenyl]sulfone, bis[4-(3-maleimidophenoxy)phenyl]ether, bis[4-(4-maleimidophenoxy)phenyl]ether , 1,4-bis[4-(4-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, 1 , 4-bis[4-(3-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(3-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, 1,4 -bis[4-(4-maleimidophenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-maleimidophenoxy)-3,5-dimethyl-α, α-dimethylbenzyl]benzene, 1,4-bis[4-(3-maleimidophenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(3-maleimidophenoxy) )-3,5-dimethyl-α,α-dimethylbenzyl]benzene and aromatic hydrocarbon group-containing maleimides such as polyphenylmethane maleimide.
Among these, bis(4-maleimidophenyl)methane, bis(4-maleimidophenyl)sulfone, bis(4-maleimidophenyl)sulfide, bis(4 -maleimidophenyl) disulfide, N,N'-(1,3-phenylene)bismaleimide, and 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane are preferred, and from the viewpoint of low cost, bis (4-Maleimidophenyl)methane and N,N'-(1,3-phenylene)bismaleimide are preferred, and bis(4-maleimidophenyl)methane is particularly preferred from the viewpoint of solubility in solvents.

The maleimide compound is a maleimide compound having an N-substituted maleimide group obtained by reacting a maleimide compound (a1), a monoamine compound (a2) having an acidic substituent, and a diamine compound (a3). preferable.
Examples of the monoamine compound (a2) having an acidic substituent include 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, 3,5-dicarboxyaniline and the like.
Examples of the diamine compound (a3) 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, 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'-tetramethylchloro-4,4'-diaminodiphenylmethane, 2,2',6,6'-tetrabromo-4,4'-diaminodiphenylmethane and the like. Among these, 4,4'-diaminodiphenylmethane and 3,3'-diethyl-4,4'-diaminodiphenylmethane are preferred from the viewpoint of being inexpensive, and 4,4'-diphenylmethane from the viewpoint of solubility in solvents. Diaminodiphenylmethane is more preferred.

In the reaction of the maleimide compound (a1), the monoamine compound (a2) having an acidic substituent, and the diamine compound (a3), the amounts of the three used are such that the monoamine compound (a2) having an acidic substituent and the diamine compound (a3) are It is preferable that the relationship between the sum of the primary amino group equivalents [denoted as —NH ₂ group equivalents] and the maleimide group equivalents of the maleimide compound (a1) satisfies the following formula.
0.1 ≤ [maleimide group equivalent] / [sum of —NH ₂ group equivalents] ≤ 10
By setting the [maleimide group equivalent]/[total of _—NH2 group equivalents] to 0.1 or more, gelation and heat resistance do not decrease. It is preferable because the solubility, metal foil adhesion and heat resistance do not deteriorate.
From the same point of view, more preferably
1 ≤ [maleimide group equivalent] / [sum of —NH ₂ group equivalents] ≤ 9, more preferably
2≦[maleimide group equivalent]/[sum of —NH ₂ group equivalents]≦8.

The content of (A) the thermosetting resin in the thermosetting resin composition is preferably 15 to 80 parts by weight, preferably 25 to 70 parts by weight, with respect to 100 parts by weight of the resin component in the thermosetting resin composition. is more preferred, and 35 to 60 parts by mass is even more preferred. The resin component in the thermosetting resin composition is, for example, (A) thermosetting resin, (B) curing agent, (C) curing accelerator and the like.

((B) curing agent)
The thermosetting resin composition may contain (B) a curing agent in order to cure (A) the thermosetting resin. (B) The curing agent is not particularly limited, and can be appropriately selected and used from those conventionally used as curing agents for thermosetting resins.
(B) Curing agents may be used alone or in combination of two or more.
(B) Curing agents include phenolic resin curing agents, acid anhydride curing agents, amine curing agents, dicyandiamide, cyanate resin curing agents, etc. when an epoxy resin is used as the thermosetting resin (A). be done. Among these, phenolic resin-based curing agents are preferable from the viewpoint of moldability and insulation reliability.

The phenolic resin-based curing agent is not particularly limited as long as it is a phenolic resin having two or more phenolic hydroxyl groups in one molecule. compounds having a phenolic hydroxyl group; aralkyl-type phenolic resin; dicyclopentadiene-type phenolic resin; triphenylmethane-type phenolic resin; type phenolic resin; copolymerized phenolic resin of benzaldehyde-type phenol and aralkyl-type phenol; p-xylylene and/or m-xylylene-modified phenolic resin; melamine-modified phenolic resin; terpene-modified phenolic resin; Examples include pentadiene-modified phenol resins; polycyclic aromatic ring-modified phenol resins; and biphenyl-type phenol resins. Among these, novolak-type phenolic resins are preferred, and cresol novolak resins are more preferred.

Acid anhydride curing agents include phthalic anhydride, 3-methyl-1,2,3,6-tetrahydrophthalic anhydride, 4-methyl-1,2,3,6-tetrahydrophthalic anhydride, 3-methyl Hexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, methyl-3,6-endomethylene-1,2,3,6-tetrahydrophthalic anhydride, benzophenonetetracarboxylic dianhydride, methylhimic acid, etc. is mentioned.
Amine-based curing agents include chain aliphatic polyamines such as diethylenetriamine, triethylenetetraamine and diethylaminopropylamine; cycloaliphatic polyamines such as N-aminoethylpiperazine and isophoronediamine; aromatic rings such as m-xylylenediamine. aromatic amines such as m-phenylenediamine, diaminodiphenylmethane and diaminodiphenylsulfone; and guanyl urea.
Examples of cyanate resin curing agents include 2,2-bis(4-cyanatophenyl)propane, bis(4-cyanatophenyl)ethane, bis(3,5-dimethyl-4-cyanatophenyl)methane, 2, 2-bis(4-cyanatophenyl)-1,1,1,3,3,3-hexafluoropropane, α,α'-bis(4-cyanatophenyl)-m-diisopropylbenzene, phenol-added dicyclo Pentadiene polymer cyanate ester compounds, phenol novolac type cyanate ester compounds, cresol novolak type cyanate ester compounds, and the like are included.

When the thermosetting resin composition contains (B) a curing agent, the content thereof is preferably 15 to 80 parts by mass, preferably 25 to 70 parts by mass, with respect to 100 parts by mass of the resin component in the thermosetting resin composition. Parts by mass are more preferable, and 35 to 60 parts by mass are even more preferable.

(A) When an epoxy resin is used as the thermosetting resin, the equivalent ratio (active hydrogen/epoxy group) between the epoxy group derived from the epoxy resin and the active hydrogen with respect to the epoxy group derived from the curing agent (B) is 0. 0.5 to 3 is preferred, 0.7 to 2.5 is more preferred, and 0.8 to 2.2 is even more preferred.

((C) curing accelerator)
(C) The curing accelerator is not particularly limited, and can be appropriately selected and used from those conventionally used as curing accelerators for thermosetting resins.
(C) A hardening accelerator may be used individually by 1 type, and may use 2 or more types together.
(C) Curing accelerators include phosphorus compounds; imidazole compounds and derivatives thereof; tertiary amine compounds; quaternary ammonium compounds and the like. Among these, imidazole compounds and derivatives thereof are preferred from the viewpoint of accelerating the curing reaction.

Imidazole compounds and their derivatives include 2-methylimidazole, 2-ethylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1,2-dimethylimidazole, 2-ethyl-1-methylimidazole. , 1,2-diethylimidazole, 1-ethyl-2-methylimidazole, 2-ethyl-4-methylimidazole, 4-ethyl-2-methylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2- phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-phenyl-4,5 -dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 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 and other imidazole compounds; addition reaction products of the imidazole compound and trimellitic acid; addition reaction products of the imidazole compound and isocyanuric acid; An addition reaction product of the imidazole compound and hydrobromic acid; an addition reaction product of the imidazole compound and an epoxy resin;

When the thermosetting resin composition contains (C) a curing accelerator, its content is preferably 0.01 to 2 parts by mass with respect to 100 parts by mass of the resin component in the thermosetting resin composition, 0.02 to 1.5 parts by mass is more preferable, and 0.04 to 1 part by mass is even more preferable.

((D) inorganic filler)
From the viewpoint of low thermal expansion, the thermosetting resin composition preferably further contains (D) an inorganic filler.
(D) The inorganic filler is not particularly limited, and can be appropriately selected and used from those conventionally used as inorganic fillers for thermosetting resin compositions.
(D) An inorganic filler may be used individually by 1 type, and may use 2 or more types together.
(D) Inorganic fillers include silica, alumina, barium sulfate, talc, mica, kaolin, boehmite, beryllia, barium titanate, potassium titanate, strontium titanate, calcium titanate, aluminum carbonate, magnesium hydroxide, and water. Aluminum oxide, aluminum borate, aluminum silicate, calcium carbonate, calcium silicate, magnesium silicate, zinc borate, zinc stannate, zinc oxide, titanium oxide, silicon carbide, silicon nitride, boron nitride, clay such as calcined clay , short glass fibers, glass powder, and hollow glass beads. Glass includes E glass, T glass, D glass, and the like. Among these, silica is preferable from the viewpoint of low thermal expansion.
Examples of silica include precipitated silica produced by a wet method and having a high moisture content, and dry-process silica produced by a dry method and containing almost no bound water or the like. Dry process silica further includes pulverized silica, fumed silica, fused silica (fused spherical silica), etc. depending on the production method. Among these, fused silica is preferable from the viewpoint of low thermal expansion and high fluidity when filled in a resin.

Silica is preferably silica surface-treated with a silane coupling agent.
Silane coupling agents include aminosilane coupling agents, epoxysilane coupling agents, phenylsilane coupling agents, alkylsilane coupling agents, alkenylsilane coupling agents, alkynylsilane coupling agents, and haloalkylsilanes. coupling agent, siloxane coupling agent, hydrosilane coupling agent, silazane coupling agent, alkoxysilane coupling agent, chlorosilane coupling agent, (meth)acrylsilane coupling agent, aminosilane coupling agent coupling agents, isocyanurate silane-based coupling agents, ureidosilane-based coupling agents, mercaptosilane-based coupling agents, sulfide silane-based coupling agents, isocyanate silane-based coupling agents, and the like.

The average particle size of the inorganic filler (D) is preferably 0.01 to 6 μm, more preferably 0.1 to 5 μm, still more preferably 0.5 to 4 μm, and particularly preferably 1 to 3 μm.
In this specification, the average particle size is the particle size at the point corresponding to 50% volume when the cumulative frequency distribution curve by particle size is obtained with the total volume of the particles being 100%, and laser diffraction It can be measured with a particle size distribution analyzer using a scattering method.

When the thermosetting resin composition contains (D) an inorganic filler, the content thereof is, from the viewpoint of low thermal expansion and moldability, with respect to 100 parts by mass of the resin component in the thermosetting resin composition, It is preferably 10 to 300 parts by mass, more preferably 50 to 250 parts by mass, even more preferably 100 to 220 parts by mass, and particularly preferably 130 to 200 parts by mass.

(other ingredients)
The thermosetting resin composition contains organic fillers, flame retardants, thermoplastic resins, ultraviolet absorbers, antioxidants, photopolymerization initiators, fluorescent brighteners, adhesive It may contain other components such as improvers.

(organic solvent)
From the viewpoint of facilitating the production of prepregs, the thermosetting resin composition may be in the form of a varnish containing an organic solvent (hereinafter also referred to as "resin varnish").
Examples of organic solvents include alcohol solvents such as methanol, ethanol, propanol, butanol, methyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; butyl acetate, and propylene glycol monomethyl ether. Ester solvents such as acetate; ether solvents such as tetrahydrofuran; aromatic solvents such as toluene, xylene, mesitylene; nitrogen atom-containing solvents such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone; sulfur atom-containing solvents such as dimethyl sulfoxide Solvents and the like are included. Among these, ketone-based solvents are preferred, and methyl ethyl ketone is more preferred, from the viewpoint of solubility and appearance after application.
An organic solvent may be used individually by 1 type, and may use 2 or more types together.
The solid content concentration in the resin varnish is preferably 10 to 80% by mass, more preferably 20 to 75% by mass, even more preferably 40 to 75% by mass, from the viewpoint of handleability.
As used herein, the term "solid content" refers to the non-volatile content excluding volatile substances such as water and solvents contained in the thermosetting resin composition, and when the thermosetting resin composition is dried shows components that remain without volatilization, and also includes those that are liquid, syrup-like and wax-like at room temperature around 25°C.

[Prepreg manufacturing method]
Next, the method for manufacturing the prepreg of the present invention including the steps 1 to 3 will be described.

<Step 1>
Step 1 is a step of obtaining a prepreg precursor. The prepreg precursor is obtained by B-staging a thermosetting resin composition. After the impregnation, heat treatment is performed.

The method for impregnating the base material with the thermosetting resin composition is not particularly limited, but includes hot melt method, solvent method, and the like.
The hot-melt method is a method of directly impregnating a substrate with a thermosetting resin composition whose viscosity has been reduced by heating. A method of forming a resin film by a method such as laminating it on a substrate, and a method of directly coating a substrate with a thermosetting resin composition using a die coater or the like can be exemplified.
The solvent method is a method of impregnating a substrate with a thermosetting resin composition in the form of a resin varnish.

Here, when the hot-melt method is applied, the B-staging may be performed simultaneously with heating when the resin film is laminated on the substrate. That is, while the resin film is laminated on the base material while being heated, the heating may be continued to B-stage the thermosetting resin composition to obtain a prepreg precursor. In this case, the heating temperature during lamination and the heating temperature during B-staging may be the same or different.
Further, when the solvent method is applied, B-staging may be performed simultaneously with heating for drying the resin varnish. That is, after the substrate is immersed in the resin varnish, the organic solvent is dried by heating, and the heating may be continued to B-stage the thermosetting resin composition to obtain a prepreg precursor. In that case, the heating temperature during drying and the heating temperature during B-staging may be the same or different.
The conditions for the heat treatment in this step are not particularly limited as long as the conditions are such that the thermosetting resin composition can be B-staged, and may be appropriately determined according to the type of the thermosetting resin. The temperature of the heat treatment is, for example, 70 to 200.degree. C., may be 80 to 150.degree. C., or may be 90 to 130.degree. The heat treatment time is, for example, 1 to 30 minutes, may be 2 to 25 minutes, or may be 3 to 20 minutes. The conditions can be called lamination conditions when the hot-melt method is applied, and can be called drying conditions when the solvent method is applied.

<Step 2>
Step 2 is a step of cooling the prepreg precursor obtained in Step 1. That is, in step 2, the prepreg precursor obtained by subjecting the thermosetting resin composition to B-stage by heat treatment in step 1 is cooled to a temperature lower than at least the temperature at which the heat treatment was performed. It is a process.
By carrying out this step, the thermosetting resin composition undergoes B-staging and cooling, which is a heat history that is generally given when producing a prepreg, and the obtained prepreg precursor is a conventional It is inherent in the strain, etc., which is a factor of dimensional change, which is generated in the prepreg.
In this way, by allowing the strain due to the thermal history of heating (step 1) and cooling (step 2) to exist before step 3, which will be described later, the strain and the like are eliminated and the dimensional change is caused by step 3. It becomes possible to effectively achieve equalization of the amount. Furthermore, the distortion caused by the thermal history of heating (step 1) and cooling (step 2), which was once eliminated in step 3, will not occur even if the same thermal history is applied after step 3. Even if it occurs, it will be very small, so the prepreg obtained by the present invention will have very small variations in the amount of dimensional change.

The prepreg precursor may be cooled by natural cooling or by using a cooling device such as an air blower or cooling rolls. The surface temperature of the prepreg precursor after cooling in this step is usually 5 to 80°C, preferably 8 to 50°C, more preferably 10 to 30°C, and still more preferably room temperature.
In this specification, room temperature refers to the ambient temperature without temperature control such as heating and cooling, and is generally about 15 to 25 ° C. However, since it may change depending on the weather, season, etc., it is within the above range. It is not limited.

<Step 3>
Step 3 is a step of obtaining a prepreg, and the prepreg is obtained by subjecting the prepreg precursor cooled in step 2 to a surface heat treatment, and the surface heat treatment raises the surface temperature of the prepreg precursor. It is a process to let

By subjecting the prepreg of the present invention to step 3, it becomes a prepreg with particularly small variation in the amount of dimensional change. Although the reason is not clear, this step eliminates the distortion of the base material in the prepreg precursor that occurred in steps 1 and 2, etc., and reduces the dimensional change during curing resulting from the distortion. It is considered that the amount of dimensional change becomes uniform.
The heating method for the surface heating treatment in step 3 is not particularly limited, and includes a heating method using a panel heater, a heating method using hot air, a heating method using high frequency waves, a heating method using magnetic lines of force, a heating method using a laser, and a combination of these heating methods. is mentioned.
The heating conditions for the surface heat treatment are such that the surface temperature of the prepreg precursor rises above the surface temperature before the surface heat treatment, and the properties (e.g. fluidity) of the resulting prepreg are significantly affected. It is not particularly limited as long as it is within a range in which it is not given, and it may be appropriately determined according to the type of the thermosetting resin.
The increase in the surface temperature of the prepreg precursor due to the surface heat treatment (that is, the absolute value of the difference between the surface temperature before the surface heat treatment and the maximum surface temperature reached during the surface heat treatment) improves the moldability of the prepreg. 5 to 110°C is preferable, 20 to 90°C is more preferable, and 40 to 70°C is even more preferable, from the viewpoint of reducing variation in the amount of dimensional change while maintaining the temperature.
As for the heating temperature of the surface heat treatment, the surface temperature of the prepreg precursor is, for example, 20 to 130° C., preferably 40 to 110° C., from the viewpoint of reducing variation in the amount of dimensional change while maintaining good moldability of the prepreg. °C, more preferably 60 to 90°C.
In addition, the surface heat treatment is performed from the viewpoint of maintaining good productivity of the prepreg, and maintaining the prepreg in the B-stage state and reducing the variation in the amount of dimensional change while maintaining good moldability. It is preferable to heat at a higher temperature and for a shorter period of time than the heating for staging. From this point of view, the surface heat treatment is preferably performed in an environment of 200 to 700°C, more preferably in an environment of 250 to 600°C, and even more preferably in an environment of 350 to 550°C. As a specific example, when a heating method using a panel heater is performed, the heating setting temperature of the panel heater is preferably 200 to 700 ° C., more preferably 250 to 600 ° C., and 350 to 550 ° C. It is even more preferable to have
The heating time of the surface heat treatment is from 1.0 to 1.0 from the viewpoint of maintaining good productivity of the prepreg, and from the viewpoint of keeping the prepreg in the B-stage state and reducing the variation in the amount of dimensional change while maintaining good moldability. 10.0 seconds is preferred, 1.5 to 6.0 seconds is more preferred, and 2.0 to 4.0 seconds is even more preferred.

The prepreg obtained in step 3 is preferably subjected to a cooling step for cooling from the viewpoint of prepreg handleability and tackiness. The cooling of the prepreg may be performed by natural cooling, or may be performed using a cooling device such as an air blower or a cooling roll. The temperature of the prepreg after cooling is usually 5 to 80°C, preferably 8 to 50°C, more preferably 10 to 30°C, and still more preferably room temperature.

In addition, the step 3 may be carried out in the manufacturing steps of the metal-clad laminate of the present invention, which will be described later. Specifically, the step 3 may be performed with the metal foils arranged on both sides of the prepreg precursor obtained in the step 2, and then the prepreg and the metal foil may be laminate-molded. The conditions and the like for lamination molding are as described later in the section on the laminate of the present invention.

The solid content of the thermosetting resin composition in the prepreg of the present invention is preferably 20 to 90% by mass, more preferably 30 to 80% by mass, and even more preferably 40 to 75% by mass.
The thickness of the prepreg of the present invention is, for example, 0.01 to 0.5 mm, preferably 0.02 to 0.2 mm, and 0.03 to 0.5 mm from the viewpoint of enabling moldability and high-density wiring. 1 mm is more preferred.

The prepreg of the present invention obtained as described above has a standard deviation σ determined by the following method of preferably 0.012% or less, more preferably 0.011% or less, more preferably 0.010% or less, It is more preferably 0.009% or less, particularly 0.008% or less. Although the lower limit of the standard deviation σ is not particularly limited, it is usually 0.003% or more, may be 0.005% or more, may be 0.006% or more, or may be 0.007 % or more.
How to calculate the standard deviation σ:
A copper foil having a thickness of 18 μm is laminated on both sides of one sheet of prepreg and heat-pressed at 190° C. and 2.45 MPa for 90 minutes to produce a double-sided copper-clad laminate having a thickness of 0.1 mm. In the double-sided copper-clad laminate thus obtained, holes having a diameter of 1.0 mm are drilled in the plane at locations 1 to 8 shown in FIG. Using an image measuring machine, measure the distances of three points each in the warp direction (1-7, 2-6, 3-5) and the weft direction (1-3, 8-4, 7-5) shown in FIG. and use each measured distance as the initial value. After that, the outer layer copper foil is removed and heated at 185° C. for 60 minutes in a dryer. After cooling, in the same way as the initial value measurement method, three points each in the warp direction (1-7, 2-6, 3-5) and the weft direction (1-3, 8-4, 7-5) Measure distance. From the rate of change of each measured distance with respect to the initial value [(measured value after heat treatment−initial value)×100/initial value], the average value of these rates of change is obtained, and the standard deviation σ of the average value is calculated.
Although the image measuring machine is not particularly limited, for example, "QV-A808P1L-D" (manufactured by Mitutoyo) can be used.

[Laminate]
The laminate of the present invention is obtained by laminating and molding the prepreg of the present invention and metal foil.
The laminate of the present invention can be produced, for example, by using one sheet of the prepreg of the present invention, or by laminating 2 to 20 sheets of the prepreg of the present invention, and laminating a metal foil on one or both sides thereof. can. In addition, hereinafter, a laminate having a metal foil arranged thereon may be referred to as a metal-clad laminate.

The metal of the metal foil is not particularly limited as long as it is used as an electrical insulating material.
From the viewpoint of conductivity, metals for the metal foil include copper, gold, silver, nickel, platinum, molybdenum, ruthenium, aluminum, tungsten, iron, titanium, chromium, and alloys containing at least one of these metal elements. is preferred, copper and amylnium are more preferred, and copper is even more preferred. That is, the laminate of the present invention is preferably a copper-clad laminate.
The thickness of the metal foil may be appropriately selected according to the use of the printed wiring board, etc., but is preferably 0.5 to 150 μm, more preferably 1 to 100 μm, even more preferably 5 to 50 μm, particularly preferably 5 to 30 μm.
Alternatively, the plating layer may be formed by plating a metal foil. The metal of the plating layer is not particularly limited as long as it is a metal that can be used for plating. An alloy containing at least one of is preferred.
The plating method is not particularly limited, and an electrolytic plating method, an electroless plating method, or the like can be used.

As the molding conditions for the laminate, known molding techniques for laminates for electrical insulating materials and multilayer boards can be applied. It can be molded under conditions of 100 to 250° C., pressure of 0.2 to 10 MPa, and heating time of 0.1 to 5 hours.
A multilayer board can also be produced by combining the prepreg of the present invention and an inner-layer printed wiring board and performing lamination molding.

[Printed wiring board]
The printed wiring board of the present invention contains the prepreg of the present invention or the laminate of the present invention.
The printed wiring board of the present invention can be produced, for example, by subjecting the metal foil of the laminate of the present invention to circuit processing. In circuit processing, for example, after forming a resist pattern on the surface of a metal foil, the metal foil in unnecessary parts is removed by etching, after peeling off the resist pattern, necessary through holes are formed by a drill or laser, and the resist pattern is formed again. After that, plating is applied to make the through holes conductive, and finally the resist pattern is peeled off.
On the surface of the printed wiring board thus obtained, the metal-clad laminate is further laminated under the same conditions as described above, and the circuit is processed in the same manner as described above to form a multilayer printed wiring board. can be done. In this case, it is not always necessary to form through holes, and via holes may be formed, or both may be formed. Such multi-layering may be performed as many times as necessary.

[Semiconductor package]
The semiconductor package of the present invention uses the printed wiring board of the present invention.
The semiconductor package of the present invention can be manufactured by mounting a semiconductor chip, a memory, etc. at predetermined positions on the printed wiring board of the present invention.

Next, the present invention will be described in more detail with reference to the following examples, but these examples are not intended to limit the present invention in any way. The prepreg and the like obtained in each example were evaluated for performance based on the following evaluation methods. Note that the room temperature in this example is 25°C.

[Evaluation method]
<1. Formability>
The four-layer copper-clad laminate prepared in each example was immersed in an etchant to remove the outer layer copper, and the evaluation substrates were visually checked for voids and blemishes within the surface of 340 mm×500 mm. A case where no voids or fading was confirmed was regarded as "no abnormality", and a case where voids or fading was confirmed as "abnormal", and this was used as an index of moldability.

<2. Variation in Dimensional Change>
As shown in FIG. 1, a hole with a diameter of 1.0 mm was made in the surface of the double-sided copper-clad laminate produced in each example to obtain an evaluation substrate represented by the schematic diagram of FIG.
Next, in FIG. 1, the distance between holes in the "warp direction" (1-7, 2-6, 3-5) and the distance between holes in the "weft direction" (1-3, 8- 4 and 7-5) were measured using "QV-A808P1L-D" (manufactured by Mitutoyo Corporation), and each measured distance was taken as the initial value. Next, the evaluation board was immersed in an etchant to remove the outer layer copper foil, and then heated at 185° C. for 60 minutes in a dryer. After cooling, the distance between each hole was measured by the same method as the initial value, and the measured value after heat treatment was obtained.
For each hole distance, the rate of change in the measured value after heat treatment with respect to the initial value ((initial value - measured value after heat treatment) x 100/(initial value)) is obtained, and the standard deviation σ for the average value is calculated. The standard deviation σ was used as the variation in the amount of dimensional change.

Example 1
(Preparation of prepreg precursor: steps 1 and 2)
(A) 19 parts by mass of a biphenyl aralkyl novolac type epoxy resin (epoxy equivalent: 280 to 300 g/eq) as a thermosetting resin;
(B) 16 parts by mass of a cresol novolak resin (hydroxyl equivalent: 119 g/eq) as a curing agent;
(C) 0.02 parts by mass of 2-ethyl-4-methylimidazole (manufactured by Shikoku Kasei Kogyo Co., Ltd.) as a curing accelerator;
(D) As an inorganic filler, 65 parts by mass of spherical silica (average particle size: 2 μm) was mixed and diluted with a solvent (methyl ethyl ketone) to obtain a varnish-like thermosetting resin composition (solid concentration: 70 mass %) were prepared.
This thermosetting resin composition is impregnated into a substrate glass cloth (manufactured by Nitto Boseki Co., Ltd., trade name: 1037 cloth, thickness: 0.025 mm), and then the thermosetting resin composition is B- Heated in a drying oven at 100-200° C. for 5-15 minutes until staging. After that, it was cooled to room temperature by natural cooling to obtain a prepreg precursor.

(Preparation of prepreg: step 3)
The prepreg precursor obtained above is subjected to a surface heating treatment using a panel heater at a heating temperature of 500°C and a heating time of 3 seconds so that the surface temperature of the prepreg precursor reaches 70°C. and cooled to room temperature to obtain a prepreg.
The content of the thermosetting resin composition in terms of solid content in the obtained prepreg was 70% by mass.

(Preparation of copper-clad laminate)
Using one sheet of the prepreg obtained above, 18 μm copper foil “YGP-18” (manufactured by Nippon Denki Co., Ltd.) is layered on both sides, and the temperature is 190 ° C. and the pressure is 25 kgf / cm ² (2.45 MPa). A double-sided copper-clad laminate for one sheet of prepreg was produced by heating and pressing for 1 minute.
Both copper foil surfaces of the obtained double-sided copper-clad laminate were subjected to inner layer adhesion treatment (using "BF treatment liquid" (manufactured by Hitachi Chemical Co., Ltd.). YGP-18" (manufactured by Nippon Denki Co., Ltd.) was overlaid and heat-pressed for 90 minutes at a temperature of 190° C. and a pressure of 25 kgf/cm ² (2.45 MPa) to produce a four-layer copper-clad laminate.
On the other hand, 18 μm copper foil “3EC-VLP-18” (manufactured by Mitsui Kinzoku Co., Ltd.) was layered on both sides of one prepreg and heated at a temperature of 190° C. and a pressure of 25 kgf/cm ² (2.45 MPa) for 90 minutes. By compression molding, a double-sided copper-clad laminate for one prepreg was produced.

Example 2
(Preparation of prepreg precursor: steps 1 and 2)
Component (A): A solution of the maleimide compound (A) produced in Production Example 1 below was used.
[Production Example 1]
19.2 g of 4,4′-diaminodiphenylmethane, 174.0 g of bis(4-maleimidophenyl)methane, p-aminophenol were placed in a 1 L reaction vessel equipped with a thermometer, stirrer and water meter with reflux condenser. 6.6 g and 330.0 g of dimethylacetamide were added and reacted at 100° C. for 2 hours to give a dimethylacetamide solution of maleimide compound (A) (Mw=1,370) having an acidic substituent and an N-substituted maleimide group. obtained and used as component (A).
The weight average molecular weight (Mw) was converted from a calibration curve using standard polystyrene by gel permeation chromatography (GPC). Calibration curve, 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] was approximated by a cubic equation using GPC conditions are shown below.
Apparatus: (pump: L-6200 type [manufactured by Hitachi High-Technologies Corporation]),
(Detector: L-3300 type RI [manufactured by Hitachi High-Technologies Corporation]),
(Column oven: L-655A-52 [manufactured by Hitachi High-Technologies Corporation])
Column; TSKgel SuperHZ2000 + TSKgel SuperHZ2300 (all manufactured by Tosoh Corporation)
Column size: 6.0 mm x 40 mm (guard column), 7.8 mm x 300 mm (column)
Eluent: Tetrahydrofuran Sample concentration: 20 mg/5 mL
Injection volume: 10 μL
Flow rate: 0.5 mL/min Measurement temperature: 40°C

(A) as a thermosetting resin, 45 parts by mass of the maleimide compound (A) obtained above and 30 parts by mass of a cresol novolac epoxy resin;
(B) as a component, dicyandiamide (manufactured by Nippon Carbide Industry Co., Ltd.) 2 parts by mass,
50 parts by mass of fused silica (average particle size: 1.9 μm, specific surface area: 5.8 m ² /g) treated with an aminosilane coupling agent as component (D);
25 parts by mass of a copolymer resin of styrene and maleic anhydride (styrene/maleic anhydride = 4, Mw = 11,000) as a thermoplastic resin;
As a flame retardant, 2.0 parts by mass of an aromatic phosphate in terms of phosphorus atoms,
(However, in the case of a solution, the solid content conversion amount is shown.), Methyl ethyl ketone was added so that the solid content concentration of the solution was 65 to 75% by mass, and a resin varnish was prepared.
IPC standard #3313 glass cloth (0.1 mm) was impregnated with each resin varnish obtained, dried for 4 minutes with a panel heater set to a temperature of 160 ° C. (step 1), and then allowed to cool to room temperature (step 2 ) to obtain a prepreg precursor.

(Preparation of prepreg: step 3)
The prepreg precursor obtained above is subjected to a surface heating treatment using a panel heater at a heating temperature of 500°C and a heating time of 3 seconds so that the surface temperature of the prepreg precursor reaches 70°C. and cooled to room temperature to obtain a prepreg.
The content of the thermosetting resin composition in terms of solid content in the obtained prepreg was 70% by mass.

(Preparation of copper-clad laminate)
A four-layer copper-clad laminate and a double-sided copper-clad laminate were produced in the same manner as in Example 1 using one sheet of the prepreg obtained above.

[Comparative Example 1]
A prepreg, a four-layer copper-clad laminate, and a double-sided copper-clad laminate were produced in the same manner as in Example 1, except that Step 3 was not performed.

[Comparative Example 2]
A prepreg, a four-layer copper-clad laminate, and a double-sided copper-clad laminate were produced in the same manner as in Example 1, except that Step 3 was not performed in Example 2.

Table 1 shows the evaluation results of the four-layer copper-clad laminate and the double-sided copper-clad laminate obtained in each of the above examples.

The prepregs of Examples 1 and 2 had good resin embedding properties in terms of moldability, and no abnormalities such as fading and voids were observed in the laminates obtained from these prepregs. In addition, the prepregs of Examples 1 and 2 tended to have smaller dimensional variation (standard deviation (σ)) than the prepregs of Comparative Examples 1 and 2, which were not subjected to surface heat treatment.

INDUSTRIAL APPLICABILITY The prepreg of the present invention is excellent in moldability and exhibits little variation in dimensional change, and is therefore useful as highly integrated semiconductor packages, printed wiring boards for electronic devices, and the like.

Claims (10)

A method for manufacturing a prepreg having the following steps 1 to 3.
Step 1: A step of obtaining a prepreg precursor, wherein the prepreg precursor is obtained by B-staging a thermosetting resin composition, and the B-staging includes impregnating a base material with the thermosetting resin composition. After that, the thermosetting resin composition is subjected to heat treatment, and the (D) inorganic filler is added to 50 to 300 parts by mass with respect to 100 parts by mass of the resin component in the thermosetting resin composition. contains part .
Step 2: A step of cooling the prepreg precursor obtained in Step 1.
Step 3: A step of obtaining a prepreg, wherein the prepreg is obtained by subjecting the prepreg precursor cooled in step 2 to a surface heating treatment (excluding hot pressure treatment), and the surface heating The treatment is a treatment for raising the surface temperature of the prepreg precursor, and the heating time of the surface heating treatment in step 3 is 1.0 to 6.0 seconds . The method for producing a prepreg according to claim 1, wherein the surface heating treatment in step 3 is a treatment for raising the surface temperature of the prepreg precursor by 5 to 110°C. The method for producing a prepreg according to claim 1 or 2, wherein the surface heating treatment in step 3 is a treatment of heating the surface temperature of the prepreg precursor to 20 to 130°C. The method for producing a prepreg according to any one of claims 1 to 3, wherein the surface heat treatment in step 3 is a treatment of heating the prepreg precursor in an environment of 200 to 700°C. The method for producing a prepreg according to claim 4, wherein the surface heat treatment in step 3 is a treatment of heating the prepreg precursor in an environment of 350 to 700°C. The method for producing a prepreg according to any one of claims 1 to 5, wherein the heating time of the surface heat treatment in step 3 is 1.0 to 4.0 seconds. The method for producing a prepreg according to any one of claims 1 to 6, wherein the base material is glass cloth. A method for producing a laminate by laminating and molding a prepreg produced by the method for producing a prepreg according to any one of claims 1 to 7 and a metal foil. A method for manufacturing a printed wiring board using a prepreg manufactured by the method for manufacturing a prepreg according to any one of claims 1 to 7 or a laminate manufactured by the method for manufacturing a laminate according to claim 8. A method for manufacturing a semiconductor package using a printed wiring board manufactured by the method for manufacturing a printed wiring board according to claim 9 .

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