JP2024058172A - Resin composition - Google Patents

Abstract

[Problem] To provide a resin composition that can keep the dielectric tangent low even in a high temperature environment and can give a cured product with excellent crack resistance after desmearing. [Solution] A resin composition comprising (A) an organic filler having liquid crystal properties, (B) an epoxy resin, and (C) an active ester compound. [Selected Figure] None

Description

The present invention relates to a resin composition containing an epoxy resin. It also relates to a cured product, a sheet-like laminate material, a resin sheet, a printed wiring board, and a semiconductor device obtained by using the resin composition.

A known manufacturing technique for printed wiring boards is the build-up method, in which insulating layers and conductor layers are alternately stacked. In build-up manufacturing methods, the insulating layer is generally formed by curing a resin composition. The insulating layer of the printed wiring board of a semiconductor device is required to exhibit good dielectric properties (low dielectric constant, low dielectric tangent) to suppress transmission loss when operating in a high-frequency environment.

For example, Patent Document 1 reports a resin composition that contains an active ester compound as a curing agent for epoxy resin, as a resin composition that produces a cured product with good dielectric properties.

JP 2009-235165 A

As described in Patent Document 1, a resin composition containing an active ester compound as a curing agent produces a cured product with superior dielectric properties compared to a typical phenol-based curing agent, but it is prone to cracking after desmearing. In addition, semiconductor devices may be exposed to high-temperature environments, such as when operating in a high-frequency environment. It has been found that even materials that exhibit good dielectric properties in a room-temperature environment may have deteriorated dielectric properties (particularly the dielectric tangent) in a high-temperature environment, and may not achieve the desired dielectric properties in an actual usage environment.

The object of the present invention is to provide a resin composition capable of suppressing the dielectric tangent to a low value even in a high-temperature environment and capable of obtaining a cured product having excellent crack resistance after a desmearing treatment, as well as a cured product, a sheet-like laminate material, a resin sheet, a printed wiring board, and a semiconductor device obtained using the resin composition.

In order to achieve the object of the present invention, the inventors conducted extensive research and discovered that by using an epoxy resin and an active ester compound as components of a resin composition, and further containing an organic filler having liquid crystallinity, it is possible to obtain a cured product that can suppress the dielectric tangent even in a high temperature environment and that can suppress the occurrence of cracks after a desmearing treatment, and thus completed the present invention.

That is, the present invention includes the following.
[1]
A resin composition comprising (A) an organic filler having liquid crystal properties, (B) an epoxy resin, and (C) an active ester compound.
[2]
The resin composition according to the above-mentioned [1], wherein the content of the (A) component is 0.1 mass% or more and 10 mass% or less, when the resin component in the resin composition is 100 mass%.
[3]
The resin composition according to the above [1] or [2], wherein the melting point of the organic filler having liquid crystallinity (A) is 270° C. or higher.
[4]
The resin composition according to any one of the above [1] to [3], further comprising (D) an inorganic filler.
[5]
The resin composition according to any one of the above [1] to [4], further comprising (E) a radically polymerizable compound.
[6]
The resin composition according to any one of the above [1] to [5], which is for forming an interlayer insulating layer of a printed wiring board.
[7]
A cured product of the resin composition according to any one of the above [1] to [6].
[8]
A sheet-like laminate material comprising the resin composition according to any one of the above items [1] to [6].
[9]
A resin sheet comprising a support and a resin composition layer formed from the resin composition according to any one of items [1] to [6] above, provided on the support.
[10]
A printed wiring board comprising an insulating layer made of a cured product of the resin composition according to any one of [1] to [6] above.
[11]
A semiconductor device comprising the printed wiring board according to [10] above.

The present invention provides a resin composition that can keep the dielectric tangent low even in a high-temperature environment and can produce a cured product that has excellent crack resistance after desmearing; a cured product of the resin composition; a sheet-like laminate material and a resin sheet that contain the resin composition; and a printed wiring board and a semiconductor device that contain the cured product of the resin composition.

The present invention will be described in detail below with reference to embodiments and examples. However, the present invention is not limited to the following embodiments and examples, and may be modified as desired without departing from the scope of the claims of the present invention and their equivalents.

In the following description, the amount of each component is the amount of non-volatile component, unless otherwise specified.
In the following description, unless otherwise specified, the "non-volatile components in the resin composition" may include the inorganic filler (D), while the "resin components" refers to the non-volatile components contained in the resin composition excluding the inorganic filler (D), unless otherwise specified.

<Resin Composition>
The resin composition of the present invention contains (A) an organic filler having liquid crystallinity, (B) an epoxy resin, and (C) an active ester compound. By using such a resin composition, it is possible to suppress the dielectric tangent low even in a high temperature environment such as 90°C, and to obtain a cured product having excellent crack resistance after desmearing. In addition, in the present invention, it is also possible to obtain a cured product having a low dielectric tangent even at room temperature such as 23°C or at normal temperature.

The resin composition of the present invention may further contain optional components in addition to (A) an organic filler having liquid crystal properties, (B) an epoxy resin, and (C) an active ester compound. Examples of optional components include (D) an inorganic filler, (E) a radically polymerizable compound, (F) other curing agents, (G) a curing accelerator, (H) other additives, and (K) an organic solvent. In this specification, each of the above components (A) to (K) may also be referred to as "component (A)", "component (B)", etc. Each component contained in the resin composition will be described in detail below.

<(A) Organic Filler Having Liquid Crystalline Properties>
The organic filler (A) having liquid crystallinity is specifically a filler containing an organic polymer having liquid crystallinity, and may be a filler made of an organic polymer having liquid crystallinity. The component (A) may be used alone or in combination of two or more. In this specification, "having liquid crystallinity" means that anisotropy is observed by polarizing microscope observation when heated to the melting point or higher.

Examples of organic polymers having liquid crystallinity include general liquid crystal polymers, such as fully aromatic polyesters synthesized from parahydroxybenzoic acid, biphenol, terephthalic acid, etc., and specifically include polymers having at least one structural unit selected from the group consisting of a structural unit derived from parahydroxybenzoic acid ([-O-C ₆ H ₄ -CO-]), a structural unit derived from biphenol ([-O-C ₆ H ₄ -C ₆ H ₄ -O-]), and a structural unit derived from terephthalic acid ([-OC-C ₆ H ₄ -CO-]). The structural unit referred to in this specification includes a repeating unit present in the main chain of the polymer and a unit or terminal group present in the terminal or side chain. As the liquid crystal polymer, for example, the liquid crystal polymer particles described in JP-A-2022-79336 can be preferably used.

The melting point of the liquid crystal organic polymer is preferably 270°C or higher, more preferably 280°C or higher, and even more preferably 290°C or higher, with the upper limit being preferably 370°C or lower, preferably 360°C or lower, and even more preferably 350°C or lower. In this specification, the melting point of the liquid crystal polymer complies with the test methods of ISO11357 and ASTM D3418, and can be measured using a differential scanning calorimeter (DSC) manufactured by Hitachi High-Tech Science Corporation, etc.

When the organic polymer having liquid crystallinity has the above melting point, it is generally poorly compatible with the epoxy resin (B) and the active ester compound (C), which generally have a relatively small average molecular weight, even under typical curing conditions in the resin composition of the present invention, and is likely to contribute to stress relaxation of the cured product obtained using the resin composition, and tends to improve the crack resistance after desmearing.

As the filler of component (A), particles, powder or powder are preferred, and the particle size distribution of the powder is, for example, 0.1 μm or more, preferably 0.3 μm or more, more preferably 0.4 μm or more, even more preferably 0.5 μm or more, even more preferably 1 μm or more, particularly preferably 3 μm or more, and for example, 12 μm or less, 10 μm or less, preferably 8 μm or less, more preferably 6 μm or less, even more preferably 5.5 μm or less, and particularly preferably 5 μm. The above particle size can be measured by a laser diffraction/scattering method based on the Mie scattering theory. Specifically, the particle size distribution of the inorganic filler is created on a volume basis using a laser diffraction/scattering particle size distribution measuring device, and the median diameter is used as the average particle size.

The amount of acetic acid outgassed from an organic polymer having liquid crystallinity when heated at 190°C for 1 hour is, for example, 10 ppm or less, preferably 5 ppm or less, and more preferably 1 ppm or less. The amount of acetic acid outgassed from an organic polymer having liquid crystallinity can be controlled by adjusting the conditions in the synthesis process of the liquid crystal polymer, which is the raw material, such as the heating temperature and time of solid-phase polymerization. If the amount of acetic acid outgassed is small as described above, it is easy to reduce the increase in dielectric tangent in the cured product obtained using the resin composition, even in a situation where molecular motion generally increases in a high-temperature environment.

The dielectric loss tangent of the liquid crystal organic polymer (measurement frequency: 10 GHz) is 0.001 or less, preferably 0.0009 or less, more preferably 0.0008 or less, and even more preferably 0.0007 or less. This value is the measured value of the dielectric loss tangent in the in-plane direction of an injection molded product of the liquid crystal organic polymer. The injection molded product is a flat test piece of 30 mm x 30 mm x 0.4 mm (thickness).

Although the mechanism of the resin composition of the present invention is not entirely clear, it is presumed that the inclusion of component (A) that is liquid crystalline, i.e., has a rigid portion in the molecule, reduces the increase in dielectric tangent in the cured product obtained using the resin composition even in a high-temperature environment where molecular motion generally increases, and that component (A) does not react with the active ester compound (C), which contributes to stress relaxation in the cured product and improves crack resistance after desmearing. Component (A) is preferably insoluble in epoxy resin (B), more preferably insoluble in the resin in the resin composition of the present invention even if the resin composition of the present invention contains a resin other than component (B), and even more preferably insoluble in the resin and organic solvent in the resin composition of the present invention even if the resin composition of the present invention further contains an organic solvent (K).

The content of component (A) is, relative to 100% by mass of non-volatile components in the resin composition, for example, 0.1% by mass or more, preferably 0.3% by mass or more, more preferably 0.4% by mass or more, even more preferably 0.5% by mass or more, and even more preferably 0.55% by mass or more, and is, for example, 5% by mass or less, preferably 4% by mass or less, more preferably 3.5% by mass or less, even more preferably 3% by mass or less, and even more preferably 2.5% by mass or less.

The content of component (A) is, relative to 100% by mass of the resin components in the resin composition, for example, 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 1.5% by mass or more, even more preferably 2% by mass or more, and for example, 12% by mass or less, preferably 10% by mass or less, more preferably 9.5% by mass or less, even more preferably 9% by mass or less, even more preferably 8.5% by mass or less.

<(B) Epoxy Resin>
The resin composition of the present invention contains an epoxy resin (B). The epoxy resin (B) means a curable resin having an epoxy group.

(B) Examples of epoxy resins include bixylenol type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol AF type epoxy resins, dicyclopentadiene type epoxy resins, trisphenol type epoxy resins, naphthol novolac type epoxy resins, phenol novolac type epoxy resins, tert-butyl-catechol type epoxy resins, naphthalene type epoxy resins, naphthol type epoxy resins, anthracene type epoxy resins, glycidylamine type epoxy resins, and glycidyl ester type epoxy resins. Examples of the epoxy resins include cresol novolac type epoxy resins, phenol aralkyl type epoxy resins, biphenyl type epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexane type epoxy resins, cyclohexane dimethanol type epoxy resins, naphthylene ether type epoxy resins, trimethylol type epoxy resins, tetraphenylethane type epoxy resins, isocyanurate type epoxy resins, phenolphthalimidine type epoxy resins, and phenolphthalein type epoxy resins. (B) The epoxy resin may be used alone or in combination of two or more.

The resin composition preferably contains, as the epoxy resin (B), an epoxy resin having two or more epoxy groups in one molecule. The proportion of the epoxy resin having two or more epoxy groups in one molecule relative to 100% by mass of the non-volatile components of the epoxy resin (B) is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more.

Epoxy resins include epoxy resins that are liquid at a temperature of 20°C (hereinafter sometimes referred to as "liquid epoxy resins") and epoxy resins that are solid at a temperature of 20°C (hereinafter sometimes referred to as "solid epoxy resins"). The resin composition of the present invention may contain only liquid epoxy resins as epoxy resins, or may contain only solid epoxy resins, or may contain a combination of liquid epoxy resins and solid epoxy resins. The epoxy resin in the resin composition of the present invention is preferably a solid epoxy resin or a combination of liquid epoxy resins and solid epoxy resins, and more preferably a solid epoxy resin.

Preferably, the liquid epoxy resin has two or more epoxy groups in one molecule.

Preferred liquid epoxy resins are bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, phenol novolac type epoxy resins, alicyclic epoxy resins having an ester skeleton, cyclohexane type epoxy resins, cyclohexane dimethanol type epoxy resins, and epoxy resins having a butadiene structure.

Specific examples of liquid epoxy resins include DIC's "HP4032", "HP4032D", and "HP4032SS" (naphthalene type epoxy resins); Mitsubishi Chemical's "828US", "828EL", "jER828EL", "825", and "Epicoat 828EL" (bisphenol A type epoxy resins); Mitsubishi Chemical's "jER807" and "1750" (bisphenol F type epoxy resins); Mitsubishi Chemical's "jER152" (phenol novolac type epoxy resin); Mitsubishi Chemical's "630", "630LSD", and "604" (glycidylamine type epoxy resins); ADEKA's "ED-523T" (glycilol type epoxy resin); ADEKA's "EP-3950L" and "EP-3 980S (glycidylamine type epoxy resin); ADEKA's "EP-4088S" (dicyclopentadiene type epoxy resin); Nippon Steel & Sumitomo Metal Chemical's "ZX1059" (mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin); Nagase ChemteX's "EX-721" (glycidyl ester type epoxy resin); Daicel's "Celloxide 2021P" (alicyclic epoxy resin having an ester skeleton); Daicel's "PB-3600", Nippon Soda's "JP-100" and "JP-200" (epoxy resin having a butadiene structure); Nippon Steel & Sumitomo Metal Chemical's "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane type epoxy resin). These may be used alone or in combination of two or more types.

As the solid epoxy resin, a solid epoxy resin having three or more epoxy groups in one molecule is preferable, and an aromatic solid epoxy resin having three or more epoxy groups in one molecule is more preferable.

Preferred solid epoxy resins are bixylenol type epoxy resins, naphthalene type epoxy resins, naphthalene type tetrafunctional epoxy resins, naphthol novolac type epoxy resins, cresol novolac type epoxy resins, dicyclopentadiene type epoxy resins, trisphenol type epoxy resins, naphthol type epoxy resins, biphenyl type epoxy resins, naphthylene ether type epoxy resins, anthracene type epoxy resins, bisphenol A type epoxy resins, bisphenol AF type epoxy resins, phenol aralkyl type epoxy resins, tetraphenylethane type epoxy resins, phenolphthalimidine type epoxy resins, and phenolphthalein type epoxy resins.

Specific examples of solid epoxy resins include DIC's "HP4032H" (naphthalene type epoxy resin); DIC's "HP-4700" and "HP-4710" (naphthalene type tetrafunctional epoxy resin); DIC's "N-690" (cresol novolac type epoxy resin); DIC's "N-695" (cresol novolac type epoxy resin); DIC's "HP-7200", "HP-7200HH", "HP-7200H", and "HP-7200L" (dicyclopentadiene type epoxy resin); DIC's "EXA-73 11", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000" (naphthylene ether type epoxy resin); "EPPN-502H" (trisphenol type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC7000L" (naphthol novolac type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC3000H", "NC3000", "NC3000L", "NC3000FH", "NC3100" (biphenyl type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ESN475V" manufactured by Nippon Steel Chemical & Material Co., Ltd. (naphthalene type epoxy resin); "ESN485" (naphthol type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ESN375" (dihydroxynaphthalene type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YX4000H", "YX4000", "YX4000HK", "YL7890" (bixylenol type epoxy resin) manufactured by Mitsubishi Chemical Co., Ltd.; "YL6121" (biphenyl type epoxy resin) manufactured by Mitsubishi Chemical Co., Ltd.; "YX8800" (anthracene type epoxy resin) manufactured by Mitsubishi Chemical Co., Ltd.; "YX77" manufactured by Mitsubishi Chemical Co., Ltd. 00" (phenol aralkyl type epoxy resin); "PG-100" and "CG-500" manufactured by Osaka Gas Chemicals; "YL7760" (bisphenol AF type epoxy resin) manufactured by Mitsubishi Chemical; "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical; "jER1010" (bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical; "jER1031S" (tetraphenylethane type epoxy resin) manufactured by Mitsubishi Chemical; "WHR991S" (phenolphthalimidine type epoxy resin) manufactured by Nippon Kayaku Co., Ltd. These may be used alone or in combination of two or more types.

When a liquid epoxy resin and a solid epoxy resin are used in combination as the (B) epoxy resin, the mass ratio of the liquid epoxy resin to the solid epoxy resin (liquid epoxy resin/solid epoxy resin) is not particularly limited, but is preferably 10 or less, more preferably 5 or less, and even more preferably 1 or less.

The epoxy equivalent of the (B) epoxy resin is preferably 50 g/eq. to 5,000 g/eq., more preferably 60 g/eq. to 2,000 g/eq., even more preferably 70 g/eq. to 1,000 g/eq., and even more preferably 80 g/eq. to 500 g/eq. The epoxy equivalent is the mass of the resin per equivalent of epoxy groups. This epoxy equivalent can be measured according to JIS K7236.

(B) The weight average molecular weight (Mw) of the epoxy resin is preferably 100 to 5,000, more preferably 250 to 3,000, and even more preferably 400 to 1,500. The weight average molecular weight of the resin can be measured by gel permeation chromatography (GPC) as a polystyrene-equivalent value.

The content of component (B) is, relative to 100% by mass of non-volatile components in the resin composition, for example, 1% by mass or more, preferably 3% by mass or more, more preferably 5% by mass or more, even more preferably 8% by mass or more, even more preferably 8.5% by mass or more, and for example, 30% by mass or less, preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 13% by mass or less, even more preferably 10% by mass or less.

The content of component (B) is, relative to 100% by mass of the resin components in the resin composition, for example, 10% by mass or more, preferably 15% by mass or more, more preferably 20% by mass or more, even more preferably 25% by mass or more, even more preferably 28% by mass or more, and particularly preferably 30% by mass or more, and is, for example, 60% by mass or less, preferably 55% by mass or less, more preferably 50% by mass or less, even more preferably 45% by mass or less, even more preferably 40% by mass or less, and particularly preferably 35% by mass or less.

<(C) Active Ester Compound>
The resin composition of the present invention contains an active ester compound (C). The active ester compound (C) may be used alone or in any combination of two or more kinds in any ratio. The active ester compound (C) may have a function of reacting with the epoxy resin (B) to crosslink the epoxy resin (B). The active ester compound (C) may have a carbon-carbon unsaturated bond, and this unsaturated bond is preferably a carbon-carbon double bond, and may be, for example, the same as the carbon-carbon unsaturated bond contained in the component (C1) described below.

(C) As the active ester compound, generally, compounds having two or more highly reactive ester groups in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds, are preferably used. The active ester compound is preferably one obtained by a condensation reaction between a carboxylic acid compound and/or a thiocarboxylic acid compound and a hydroxy compound and/or a thiol compound. In particular, from the viewpoint of improving heat resistance, an active ester compound obtained from a carboxylic acid compound and a hydroxy compound is preferred, and an active ester compound obtained from a carboxylic acid compound and a phenol compound and/or a naphthol compound is more preferred. Examples of the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of phenol compounds or naphthol compounds include hydroquinone, resorcin, bisphenol A, bisphenol F, bisphenol S, phenolphthaline, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadiene-type diphenol compounds, and phenol novolak. Here, "dicyclopentadiene-type diphenol compounds" refer to diphenol compounds obtained by condensing one molecule of dicyclopentadiene with two molecules of phenol.

Specifically, the active ester compound (C) is preferably a dicyclopentadiene type active ester compound, a naphthalene type active ester compound containing a naphthalene structure, an active ester compound containing an acetylated product of phenol novolac, or an active ester compound containing a benzoylated product of phenol novolac, and among these, at least one selected from a dicyclopentadiene type active ester compound and a naphthalene type active ester compound is more preferable, and a dicyclopentadiene type active ester compound is even more preferable. As the dicyclopentadiene type active ester compound, an active ester compound containing a dicyclopentadiene type diphenol structure is preferable. The "dicyclopentadiene type diphenol structure" refers to a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

(C) Commercially available active ester compounds include active ester compounds containing a dicyclopentadiene-type diphenol structure such as "EXB9451", "EXB9460", "EXB9460S", "EXB-8000L", "EXB-8000L-65M", "EXB-8000L-65TM", "HPC-8000L-65TM", "HPC-8000", "HPC-8000-65T", "HPC-8000H", and "HPC-8000H-65TM" (manufactured by DIC Corporation); and active ester compounds containing a naphthalene structure such as "EXB-8100L-65T", "EXB-8150-60T", and "EXB-8150-62T". ", "EXB-9416-70BK", "HPC-8150-60T", "HPC-8150-62T" (manufactured by DIC Corporation); as a phosphorus-containing active ester compound, "EXB9401" (manufactured by DIC Corporation); as an active ester compound which is an acetylated product of phenol novolac, "DC808" (manufactured by Mitsubishi Chemical Corporation); as an active ester compound which is a benzoylated product of phenol novolac, "YLH1026", "YLH1030", "YLH1048" (manufactured by Mitsubishi Chemical Corporation); as an active ester compound containing a styryl group and a naphthalene structure, "PC1300-02-65MA" (manufactured by Air Water Inc.) and the like can be mentioned.

The active ester group equivalent of the (C) active ester compound is preferably 50 g/eq. to 500 g/eq., more preferably 50 g/eq. to 400 g/eq., and even more preferably 100 g/eq. to 300 g/eq. The active ester group equivalent is the mass of the active ester compound per equivalent of the active ester group.

The ratio of the amounts of the (B) and (C) components is preferably 1.0 or more, more preferably 1.01 or more, even more preferably 1.03 or more, even more preferably 1.05 or more, and particularly preferably 1.1 or more, and is preferably 2.0 or less, more preferably 1.75 or less, even more preferably 1.5 or less, even more preferably 1.3 or less, and particularly preferably 1.2 or less, where a is the total value of the mass of the non-volatile components of the (B) component divided by the epoxy equivalent, and b is the total value of the mass of the non-volatile components of the (C) component divided by the active ester group equivalent. By setting the ratio of the amounts of the (B) and (C) components within this range, the effects of the present invention can be easily obtained.

The content of component (C) is, relative to 100% by mass of non-volatile components in the resin composition, for example, 3% by mass or more, preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 13% by mass or more, even more preferably 15% by mass or more, and for example, 30% by mass or less, preferably 25% by mass or less, more preferably 20% by mass or less, even more preferably 16% by mass or less.

The content of component (C) is, relative to 100% by mass of the resin components in the resin composition, for example, 30% by mass or more, preferably 40% by mass or more, more preferably 45% by mass or more, even more preferably 50% by mass or more, and even more preferably 54% by mass or more, and is, for example, 70% by mass or less, preferably 65% by mass or less, more preferably 63% by mass or less, and even more preferably 60% by mass or less.

<(D) Inorganic filler>
The resin composition of the present invention may contain an inorganic filler (D) as an optional component. The inorganic filler (D) is contained in the resin composition in the form of particles. The inorganic filler (D) may be used alone or in any combination of two or more kinds.

(D) An inorganic compound is used as the material for the inorganic filler. (D) Examples of the material for the inorganic filler include silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, silica is particularly suitable. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. In addition, spherical silica is preferable as the silica. (D) The inorganic filler may be used alone or in any combination of two or more kinds in any ratio.

(D) Commercially available inorganic fillers include, for example, "SP60-05" and "SP507-05" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "SC2500SQ", "SO-C4", "SO-C2", "SO-C1", "YC100C", "YA050C", "YA050C-MJE", and "YA010C" manufactured by Admatechs Co., Ltd.; "UFP-30", "DAW-03", and "FB-105FD" manufactured by Denka Co., Ltd.; "Silfil NSS-3N", "Silfil NSS-4N", and "Silfil NSS-5N" manufactured by Tokuyama Corporation; "MGH-005" manufactured by Taiheiyo Cement Corporation; and "BA-S" manufactured by JGC Catalysts and Chemicals Co., Ltd.

(D) The average particle size of the inorganic filler is not particularly limited, but is preferably 10 μm or less, more preferably 5 μm or less, even more preferably 2 μm or less, even more preferably 1 μm or less, and particularly preferably 0.7 μm or less. (D) The lower limit of the average particle size of the inorganic filler is not particularly limited, but is preferably 0.01 μm or more, more preferably 0.05 μm or more, even more preferably 0.1 μm or more, and particularly preferably 0.2 μm or more. (D) The average particle size of the inorganic filler can be measured by a laser diffraction/scattering method based on the Mie scattering theory. Specifically, the particle size distribution of the inorganic filler is created on a volume basis using a laser diffraction/scattering particle size distribution measuring device, and the median diameter is used as the average particle size. The measurement sample can be prepared by weighing 100 mg of the inorganic filler and 10 g of methyl ethyl ketone into a vial and dispersing it by ultrasonic waves for 10 minutes. The measurement sample was measured using a laser diffraction type particle size distribution measuring device with blue and red light source wavelengths and a flow cell method to measure the volumetric particle size distribution of the inorganic filler, and the average particle size was calculated as the median diameter from the obtained particle size distribution. An example of a laser diffraction type particle size distribution measuring device is the "LA-960" manufactured by Horiba, Ltd.

The specific surface area of the inorganic filler (D) is not particularly limited, but is preferably 0.1 m ² /g or more, more preferably 0.5 m ² /g or more, even more preferably 1 m ² /g or more, and particularly preferably 3 m ² /g or more. The upper limit of the specific surface area of the inorganic filler (D) is not particularly limited, but is preferably 100 m ² /g or less, more preferably 70 m ² /g or less, even more preferably 50 m ² /g or less, and particularly preferably 40 m ² /g or less. The specific surface area of the inorganic filler is obtained by adsorbing nitrogen gas to the sample surface using a specific surface area measuring device (Macsorb HM-1210 manufactured by Mountech Co., Ltd.) according to the BET method, and calculating the specific surface area using the BET multipoint method.

It is preferable that the inorganic filler (D) is surface-treated with an appropriate surface treatment agent. By being surface-treated, the moisture resistance and dispersibility of the inorganic filler (D) can be improved. Examples of surface treatment agents include vinyl-based silane coupling agents such as vinyltrimethoxysilane and vinyltriethoxysilane; epoxy-based silane coupling agents such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane; styryl-based silane coupling agents such as p-styryltrimethoxysilane; 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3- Methacrylic silane coupling agents such as methacryloxypropylmethyldiethoxysilane and 3-methacryloxypropyltriethoxysilane; acrylic silane coupling agents such as 3-acryloxypropyltrimethoxysilane; N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-8- Amino-based silane coupling agents such as aminooctyltrimethoxysilane and N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane; isocyanurate-based silane coupling agents such as tris-(trimethoxysilylpropyl)isocyanurate; ureido-based silane coupling agents such as 3-ureidopropyltrialkoxysilane; mercapto-based silane coupling agents such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane; isocyanate-based silane coupling agents such as 3-isocyanatepropyltriethoxysilane; 3-trimethoxysilylpro Examples of the surface treatment agent include acid anhydride-based silane coupling agents such as pyrusuccinic anhydride; and non-silane coupling alkoxysilane compounds such as methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, 1,6-bis(trimethoxysilyl)hexane, and trifluoropropyltrimethoxysilane. The surface treatment agent may be used alone or in combination of two or more in any ratio.

Commercially available surface treatment agents include, for example, Shin-Etsu Chemical Co., Ltd.'s "KBM-1003" and "KBE-1003" (vinyl-based silane coupling agents); "KBM-303", "KBM-402", "KBM-403", "KBE-402", and "KBE-403" (epoxy-based silane coupling agents); "KBM-1403" (styryl-based silane coupling agents); "KBM-502", "KBM-503", "KBE-502", and "KBE-503" (methacrylic-based silane coupling agents); "KBM-5103" (acrylic-based silane coupling agents); "KBM-602", "KBM-603", "KBM-903", "KBE-903", "KBE-9103P", "KBM-573", and "KBM-575" (amino-based silane coupling agents); Examples include "KBM-9659" (isocyanurate-based silane coupling agent); "KBE-585" (ureido-based silane coupling agent); "KBM-802" and "KBM-803" (mercapto-based silane coupling agent); "KBE-9007N" (isocyanate-based silane coupling agent); "X-12-967C" (acid anhydride-based silane coupling agent); "KBM-13", "KBM-22", "KBM-103", "KBE-13", "KBE-22", "KBE-103", "KBM-3033", "KBE-3033", "KBM-3063", "KBE-3063", "KBE-3083", "KBM-3103C", "KBM-3066", and "KBM-7103" (non-silane coupling alkoxysilane compound).

From the viewpoint of improving the dispersibility of the inorganic filler, it is preferable that the degree of surface treatment with the surface treatment agent falls within a specified range. Specifically, it is preferable that 100% by mass of the inorganic filler is surface-treated with 0.2% to 5% by mass of the surface treatment agent, more preferably 0.2% to 3% by mass, and even more preferably 0.3% to 2% by mass.

The degree of surface treatment by the surface treatment agent can be evaluated by the amount of carbon per unit surface area of the inorganic filler. From the viewpoint of improving the dispersibility of the inorganic filler, the amount of carbon per unit surface area of the inorganic filler is preferably 0.02 mg/m ² or more, more preferably 0.1 mg/m ² or more, and even more preferably 0.2 mg/m ² or more. On the other hand, from the viewpoint of preventing an increase in the melt viscosity of the resin composition or the melt viscosity in the sheet form, it is preferably 1.0 mg/m ² or less, more preferably 0.8 mg/m ² or less, and even more preferably 0.5 mg/m ² or less.

(D) The amount of carbon per unit surface area of the inorganic filler can be measured after the surface-treated inorganic filler is washed with a solvent (e.g., methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent is added to the inorganic filler that has been surface-treated with a surface treatment agent, and ultrasonic cleaning is performed at 25°C for 5 minutes. After removing the supernatant and drying the solids, the amount of carbon per unit surface area of the inorganic filler can be measured using a carbon analyzer. An example of a carbon analyzer that can be used is the "EMIA-320V" manufactured by Horiba, Ltd.

The content of the inorganic filler (D) in the resin composition is not particularly limited, but when the non-volatile components in the resin composition are taken as 100 mass%, it may be preferably 95 mass% or less, more preferably 90 mass% or less, even more preferably 85 mass% or less, even more preferably 80 mass% or less, and particularly preferably 75 mass% or less. The lower limit of the content of the inorganic filler (D) in the resin composition is not particularly limited, but when the non-volatile components in the resin composition are taken as 100 mass%, it may be, for example, 0 mass% or more, 1 mass% or more, 10 mass% or more, 20 mass% or more, 30 mass% or more, etc., preferably 40 mass% or more, more preferably 50 mass% or more, even more preferably 60 mass% or more, even more preferably 65 mass% or more, and particularly preferably 70 mass% or more.

<(E) Radically Polymerizable Compound>
The resin composition of the present invention may contain a radical polymerizable compound (E) as an optional component. The radical polymerizable compound (E) may be used alone or in any combination of two or more kinds.

The type of radical polymerizable compound is not particularly limited as long as it has one or more (preferably two or more) radical polymerizable unsaturated groups in one molecule. Examples of radical polymerizable compounds include compounds having one or more radical polymerizable unsaturated groups selected from maleimide groups, vinyl groups, allyl groups, styryl groups, vinylphenyl groups, acryloyl groups, methacryloyl groups, fumaroyl groups, and maleoyl groups. Among them, from the viewpoint of easily obtaining a cured product with excellent dielectric properties, it is preferable to include (E1) a maleimide compound and/or (E2) other radical polymerizable compounds. (E2) Other radical polymerizable compounds are compounds that do not have maleimide groups and have radical polymerizable unsaturated groups other than maleimide groups, and among them, it is preferable to include one or more selected from (meth)acrylic resins and styryl resins.

(E1) The type of maleimide compound is not particularly limited, so long as it has one or more (preferably two or more) maleimide groups (2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl groups) in one molecule. Examples of maleimide compounds include maleimide resins containing an aliphatic skeleton with 36 carbon atoms derived from dimer diamine, such as "BMI-3000J", "BMI-5000", "BMI-1400", "BMI-1500", "BMI-1700", and "BMI-689" (all manufactured by DigiCner Molecules); maleimide resins containing an indane skeleton, as described in the Japan Institute of Invention and Innovation Disclosure Technical Bulletin No. 2020-500211; and maleimide resins containing an aromatic ring skeleton directly bonded to the nitrogen atom of the maleimide group, such as "MIR-3000-70MT", "MIR-5000-60T" (all manufactured by Nippon Kayaku Co., Ltd.), "BMI-4000" (manufactured by Daiwa Kasei Co., Ltd.), and "BMI-80" (manufactured by Keiai Kasei Co., Ltd.).

There is no particular limitation on the type of (meth)acrylic resin, so long as it has one or more (preferably two or more) (meth)acryloyl groups in one molecule. Here, the term "(meth)acryloyl group" is a general term for acryloyl groups and methacryloyl groups. Examples of methacrylic resins include (meth)acrylic resins such as "A-DOG" (manufactured by Shin-Nakamura Chemical Co., Ltd.), "DCP-A" (manufactured by Kyoeisha Chemical Co., Ltd.), "NPDGA", "FM-400", "R-687", "THE-330", "PET-30", and "DPHA" (all manufactured by Nippon Kayaku Co., Ltd.).

There is no particular limitation on the type of styryl resin, so long as it has one or more (preferably two or more) styryl groups or vinylphenyl groups in one molecule. Examples of styryl resins include styryl resins such as "OPE-2St", "OPE-2St 1200", and "OPE-2St 2200" (all manufactured by Mitsubishi Gas Chemical Co., Ltd.).

The content of the (E) radical polymerizable compound in the resin composition may be 0% by mass or may be greater than 0% by mass, and is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and particularly preferably 0.5% by mass or more, and is, for example, 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, and particularly preferably 1.5% by mass or less, assuming that the non-volatile components in the resin composition are 100% by mass.

The content of the (E) radical polymerizable compound in the resin composition may be 0% by mass or may be greater than 0% by mass, and is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, and particularly preferably 2.5% by mass or more, and is, for example, 20% by mass or less, preferably 10% by mass or less, more preferably 7% by mass or less, and particularly preferably 5% by mass or less, assuming that the resin component in the resin composition is 100% by mass.

<(F) Other curing agents]
The resin composition of the present invention may contain (F) other curing agents as optional components. The (F) other curing agents do not include those corresponding to the above-mentioned components (A) to (C) and (E). The (F) other curing agents, like the (C) active ester compound described above, can function as an epoxy resin curing agent that reacts with the (B) epoxy resin to cure the resin composition. The (F) other curing agents may be used alone or in combination of two or more.

(F) Examples of other curing agents include phenol-based curing agents, carbodiimide-based curing agents, acid anhydride-based curing agents, amine-based curing agents, benzoxazine-based curing agents, cyanate ester-based curing agents, and thiol-based curing agents. Of these, it is preferable to use one or more curing agents selected from the group consisting of phenol-based curing agents and carbodiimide-based curing agents.

As the phenol-based hardener, a hardener having one or more, preferably two or more, hydroxyl groups bonded to an aromatic ring such as a benzene ring or a naphthalene ring in one molecule can be used. From the viewpoint of heat resistance and water resistance, a phenol-based hardener having a novolac structure is preferred. From the viewpoint of adhesion, a nitrogen-containing phenol-based hardener is preferred, and a triazine skeleton-containing phenol-based hardener is more preferred. Among them, from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion, a triazine skeleton-containing phenol novolac resin is preferred. Specific examples of phenol-based curing agents include "MEH-7700", "MEH-7810", and "MEH-7851" manufactured by Meiwa Kasei Co., Ltd., "NHN", "CBN", and "GPH" manufactured by Nippon Kayaku Co., Ltd., "SN-170", "SN-180", "SN-190", "SN-475", "SN-485", "SN-495", "SN-375", and "SN-395" manufactured by Nippon Steel Chemical & Material Co., Ltd., and "LA-7052", "LA-7054", "LA-3018", "LA-3018-50P", "LA-1356", "TD2090", and "TD-2090-60M" manufactured by DIC Corporation.

As the carbodiimide-based curing agent, a curing agent having one or more, preferably two or more, carbodiimide structures in one molecule can be used. Specific examples of carbodiimide-based curing agents include aliphatic biscarbodiimides such as tetramethylene-bis(t-butylcarbodiimide) and cyclohexane bis(methylene-t-butylcarbodiimide); aromatic biscarbodiimides such as phenylene-bis(xylylcarbodiimide); aliphatic polycarbodiimides such as polyhexamethylenecarbodiimide, polytrimethylhexamethylenecarbodiimide, polycyclohexylenecarbodiimide, poly(methylenebiscyclohexylenecarbodiimide), and poly(isophoronecarbodiimide); poly(phenylenecarbodiimide), poly( Examples of polycarbodiimides include aromatic polycarbodiimides such as poly(naphthylenecarbodiimide), poly(tolylenecarbodiimide), poly(methyldiisopropylphenylenecarbodiimide), poly(triethylphenylenecarbodiimide), poly(diethylphenylenecarbodiimide), poly(triisopropylphenylenecarbodiimide), poly(diisopropylphenylenecarbodiimide), poly(xylylenecarbodiimide), poly(tetramethylxylylenecarbodiimide), poly(methylenediphenylenecarbodiimide), and poly[methylenebis(methylphenylene)carbodiimide]. Commercially available carbodiimide curing agents include, for example, "Carbodilite V-02B," "Carbodilite V-03," "Carbodilite V-04K," "Carbodilite V-07," and "Carbodilite V-09" manufactured by Nisshinbo Chemical Co., Ltd.; and "Stavaxol P," "Stavaxol P400," and "Hi-Kasil 510" manufactured by Rhein Chemie.

As the acid anhydride curing agent, a curing agent having one or more acid anhydride groups in one molecule can be used, and a curing agent having two or more acid anhydride groups in one molecule is preferable. Specific examples of acid anhydride curing agents include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride, and benzophenonetetracarboxylic dianhydride. anhydride, biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenylsulfonetetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan-1,3-dione, ethylene glycol bis(anhydrotrimellitate), and polymeric acid anhydrides such as styrene-maleic acid resin in which styrene and maleic acid are copolymerized. Examples of commercially available acid anhydride curing agents include "HNA-100", "MH-700", "MTA-15", "DDSA", and "OSA" manufactured by New Japan Chemical Co., Ltd.; "YH-306" and "YH-307" manufactured by Mitsubishi Chemical Corporation; "HN-2200" and "HN-5500" manufactured by Hitachi Chemical Co., Ltd.; and "EF-30", "EF-40", "EF-60", and "EF-80" manufactured by Clay Valley.

As the amine-based curing agent, a curing agent having one or more, preferably two or more, amino groups in one molecule can be used. Examples of the amine-based curing agent include aliphatic amines, polyether amines, alicyclic amines, aromatic amines, etc., and among these, aromatic amines are preferred. The amine-based curing agent is preferably a primary amine or secondary amine, and more preferably a primary amine. Specific examples of the amine-based curing agent include 4,4'-methylenebis(2,6-dimethylaniline), 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, m-phenylenediamine, m-xylylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenylether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, 2,2-bis(3-amino-4-hydroxyphenyl)propane. propane, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethanediamine, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, bis(4-(3-aminophenoxy)phenyl)sulfone, and the like. Commercially available amine-based curing agents include, for example, "SEIKACURE-S" manufactured by Seika Corporation; "KAYABOND C-200S", "KAYABOND C-100", "KAYAHARD A-A", "KAYAHARD A-B", and "KAYAHARD A-S" manufactured by Nippon Kayaku Co., Ltd.; "Epicure W" manufactured by Mitsubishi Chemical Corporation; and "DTDA" manufactured by Sumitomo Seika Chemicals Co., Ltd.

Specific examples of benzoxazine-based curing agents include "JBZ-OP100D" and "ODA-BOZ" manufactured by JFE Chemical Corporation; "HFB2006M" manufactured by Showa Polymer Co., Ltd.; and "P-d" and "F-a" manufactured by Shikoku Chemical Industry Co., Ltd.

Examples of cyanate ester curing agents include bifunctional cyanate resins such as bisphenol A dicyanate, polyphenol cyanate (oligo(3-methylene-1,5-phenylene cyanate)), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanate phenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanate phenyl-1-(methylethylidene))benzene, bis(4-cyanate phenyl)thioether, and bis(4-cyanate phenyl)ether; polyfunctional cyanate resins derived from phenol novolac and cresol novolac; and prepolymers in which these cyanate resins are partially converted to triazine. Specific examples of cyanate ester-based hardeners include Lonza Japan's "PT30" and "PT60" (both phenol novolac-type multifunctional cyanate ester resins), "BA230" and "BA230S75" (prepolymers in which part or all of bisphenol A dicyanate has been converted to triazine and formed into a trimer).

Examples of thiol-based curing agents include trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), and tris(3-mercaptopropyl)isocyanurate.

(F) The active group equivalent of the other curing agent is preferably 50 g/eq. to 3000 g/eq., more preferably 100 g/eq. to 1000 g/eq., even more preferably 100 g/eq. to 500 g/eq., and particularly preferably 100 g/eq. to 300 g/eq. The active group equivalent represents the mass of the curing agent per equivalent of active group.

The ratio of the amount of epoxy resin to the curing agent, i.e., the ratio of the amount of the (B) component to the (C) component and the (F) component, is preferably 1.0 or more, more preferably 1.01 or more, even more preferably 1.1 to 1.10 or more, even more preferably 1.15 or more, particularly preferably 1.2 or more, and is preferably 2.0 or less, more preferably 1.75 or less, even more preferably 1.5 or less, even more preferably 1.4 to 1.40 or less, and particularly preferably 1.3 or less, when the ratio of the amount of the epoxy resin to the curing agent is within such a range, the effect of the present invention can be easily obtained.

The content of (F) other curing agents in the resin composition may be 0% by mass or may be greater than 0% by mass, and is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and particularly preferably 1.0% by mass or more, and is preferably 20% by mass or less, more preferably 10% by mass or less, and particularly preferably 5% by mass or less, assuming that the non-volatile components in the resin composition are 100% by mass.

The content of (F) other curing agents in the resin composition may be 0% by mass or may be greater than 0% by mass, and is preferably 0.1% by mass or more, more preferably 1.0% by mass or more, and particularly preferably 5.0% by mass or more, and is preferably 50% by mass or less, more preferably 20% by mass or less, and particularly preferably 10% by mass or less, assuming that the resin components in the resin composition are 100% by mass.

<(G) Curing Accelerator>
The resin composition of the present invention may contain a curing accelerator (G) as an optional component.

Examples of the curing accelerator include phosphorus-based curing accelerators, urea-based curing accelerators, guanidine-based curing accelerators, imidazole-based curing accelerators, metal-based curing accelerators, and amine-based curing accelerators. (G) The curing accelerator may be used alone or in combination of two or more types.

Examples of phosphorus-based curing accelerators include aliphatic phosphonium salts such as tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium laurate, bis(tetrabutylphosphonium)pyromellitate, tetrabutylphosphonium hydrogenhexahydrophthalate, tetrabutylphosphonium 2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenolate, and di-tert-butylmethylphosphonium tetraphenylborate; methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, propyltriphenylphosphonium bromide, butyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, tetraphenylphosphine aromatic phosphonium salts such as sulfonium bromide, p-tolyltriphenylphosphonium tetra-p-tolylborate, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, triphenylethylphosphonium tetraphenylborate, tris(3-methylphenyl)ethylphosphonium tetraphenylborate, tris(2-methoxyphenyl)ethylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate; aromatic phosphine-borane complexes such as triphenylphosphine-triphenylborane; aromatic phosphine-quinone addition products such as triphenylphosphine-p-benzoquinone addition products; tributylphosphine, tri-t Aliphatic phosphines such as tert-butylphosphine, trioctylphosphine, di-tert-butyl(2-butenyl)phosphine, di-tert-butyl(3-methyl-2-butenyl)phosphine, and tricyclohexylphosphine; dibutylphenylphosphine, di-tert-butylphenylphosphine, methyldiphenylphosphine, ethyldiphenylphosphine, butyldiphenylphosphine, diphenylcyclohexylphosphine, triphenylphosphine, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tris(4-ethylphenyl)phosphine, tris(4-propylphenyl)phosphine, tris(4-isopropylphenyl)phosphine, tris(4-butylphenyl)phosphine, tris(4-tert-butylphenyl)phosphine, tris(2,4-dimethylphenyl)phosphine, ) phosphine, tris(2,5-dimethylphenyl)phosphine, tris(2,6-dimethylphenyl)phosphine, tris(3,5-dimethylphenyl)phosphine, tris(2,4,6-trimethylphenyl)phosphine, tris(2,6-dimethyl-4-ethoxyphenyl)phosphine, tris(2-methoxyphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(4-ethoxyphenyl)phosphine, tris(4-tert-butoxyphenyl)phosphine, diphenyl-2-pyridylphosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,2-bis(diphenylphosphino)acetylene, 2,2'-bis(diphenylphosphino)diphenyl ether and other aromatic phosphines.

Examples of urea-based hardening accelerators include 1,1-dimethylurea; aliphatic dimethylureas such as 1,1,3-trimethylurea, 3-ethyl-1,1-dimethylurea, 3-cyclohexyl-1,1-dimethylurea, and 3-cyclooctyl-1,1-dimethylurea; 3-phenyl-1,1-dimethylurea, 3-(4-chlorophenyl)-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea, 3-(2-methylphenyl)-1,1-dimethylurea, 3-(4-methylphenyl)-1,1-dimethylurea, and 3-(3,4-dimethylphenyl)-1,1-dimethylurea. aromatic dimethylureas such as 3-(4-isopropylphenyl)-1,1-dimethylurea, 3-(4-methoxyphenyl)-1,1-dimethylurea, 3-(4-nitrophenyl)-1,1-dimethylurea, 3-[4-(4-methoxyphenoxy)phenyl]-1,1-dimethylurea, 3-[4-(4-chlorophenoxy)phenyl]-1,1-dimethylurea, 3-[3-(trifluoromethyl)phenyl]-1,1-dimethylurea, N,N-(1,4-phenylene)bis(N',N'-dimethylurea), N,N-(4-methyl-1,3-phenylene)bis(N',N'-dimethylurea) [toluene bisdimethylurea], etc.

Examples of guanidine-based curing accelerators include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, 1-phenylbiguanide, and 1-(o-tolyl)biguanide.

Examples of imidazole-based curing accelerators include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, and 1-benzyl-2-furan. phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl- (1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, Examples include imidazole compounds such as 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, and 2-phenylimidazoline, as well as adducts of imidazole compounds and epoxy resins.

Commercially available imidazole curing accelerators may be used, such as "1B2PZ", "2MZA-PW", and "2PHZ-PW" manufactured by Shikoku Chemical Industry Co., Ltd., and "P200-H50" manufactured by Mitsubishi Chemical Corporation.

Metal-based curing accelerators include, for example, organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include organocobalt complexes such as cobalt (II) acetylacetonate and cobalt (III) acetylacetonate, organocopper complexes such as copper (II) acetylacetonate, organozinc complexes such as zinc (II) acetylacetonate, organoiron complexes such as iron (III) acetylacetonate, organonickel complexes such as nickel (II) acetylacetonate, and organomanganese complexes such as manganese (II) acetylacetonate. Organometallic salts include, for example, zinc octylate, tin octylate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

Examples of amine-based curing accelerators include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene.

Commercially available amine-based curing accelerators may be used, such as "MY-25" manufactured by Ajinomoto Fine-Techno Co., Ltd.

The content of the (G) curing accelerator in the resin composition is not particularly limited, but is preferably 15% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and particularly preferably 3% by mass or less, when the non-volatile components in the resin composition are taken as 100% by mass. The lower limit of the content of the (E) curing accelerator in the resin composition is not particularly limited, but may be, for example, 0% by mass or more, 0.001% by mass or more, 0.01% by mass or more, 0.1% by mass or more, 0.5% by mass or more, when the non-volatile components in the resin composition are taken as 100% by mass.

<(H) Other Additives>
The resin composition of the present invention may further contain any additive as a non-volatile component. Examples of such additives include radical polymerization initiators such as peroxide radical polymerization initiators and azo radical polymerization initiators; epoxy curing agents other than active ester compounds such as phenolic curing agents, naphthol curing agents, acid anhydride curing agents, thiol curing agents, benzoxazine curing agents, cyanate ester curing agents, carbodiimide curing agents, and imidazole curing agents; phenoxy resins, polyvinyl acetal resins, polyolefin resins, polysulfone resins, polyethersulfone resins, polyphenylene ether resins, polycarbonate resins, and the like. thermoplastic resins such as polyether ether ketone resins, polyether ether ketone resins, and polyester resins; organic fillers such as rubber particles; organometallic compounds such as organocopper compounds, organozinc compounds, and organocobalt compounds; colorants such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium oxide, and carbon black; polymerization inhibitors such as hydroquinone, catechol, pyrogallol, and phenothiazine; leveling agents such as silicone-based leveling agents and acrylic polymer-based leveling agents; bentone, montmorillonite, and the like. thickeners such as nitrite; defoamers such as silicone defoamers, acrylic defoamers, fluorine defoamers, and vinyl resin defoamers; ultraviolet absorbers such as benzotriazole ultraviolet absorbers; adhesion improvers such as urea silane; adhesion imparters such as triazole adhesion imparters, tetrazole adhesion imparters, and triazine adhesion imparters; antioxidants such as hindered phenol antioxidants and hindered amine antioxidants; fluorescent brighteners such as stilbene derivatives; surfactants such as fluorine surfactants and silicone surfactants; phosphorus-based flame retardants (e.g., phosphate esters Flame retardants such as aryl compounds, phosphazene compounds, phosphinic acid compounds, red phosphorus), nitrogen-based flame retardants (e.g. melamine sulfate), halogen-based flame retardants, and inorganic flame retardants (e.g. antimony trioxide); dispersants such as phosphate ester-based dispersants, polyoxyalkylene-based dispersants, acetylene-based dispersants, silicone-based dispersants, anionic dispersants, and cationic dispersants; stabilizers such as borate-based stabilizers, titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, and carboxylic anhydride-based stabilizers. (F) Other additives may be used alone or in combination of two or more at any ratio. (H) The content of other additives can be appropriately set by a person skilled in the art.

<(K) Organic Solvent>
The resin composition of the present invention may further contain an arbitrary organic solvent as a volatile component in addition to the non-volatile components described above. As the (K) organic solvent, any known organic solvent may be appropriately used, and the type is not particularly limited. As the (K) organic solvent, for example, ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.; ester-based solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, γ-butyrolactone, etc.; ether-based solvents such as tetrahydropyran, tetrahydrofuran, 1,4-dioxane, diethyl ether, diisopropyl ether, dibutyl ether, diphenyl ether, etc.; alcohol-based solvents such as methanol, ethanol, propanol, butanol, ethylene glycol, etc.; 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl diglycol acetate, γ-butyrolactone, methyl methoxypropionate, etc. Examples of the organic solvent include ether ester solvents such as methyl lactate, ethyl lactate, and methyl 2-hydroxyisobutyrate; ether alcohol solvents such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether (butyl carbitol); amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; sulfoxide solvents such as dimethyl sulfoxide; nitrile solvents such as acetonitrile and propionitrile; aliphatic hydrocarbon solvents such as hexane, cyclopentane, cyclohexane, and methylcyclohexane; and aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene. The organic solvent (K) may be used alone or in combination of two or more in any ratio.

In one embodiment, the content of (K) organic solvent is not particularly limited, but when all components in the resin composition are taken as 100% by mass, it can be, for example, 60% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less, etc.

<Method of producing resin composition>
The resin composition of the present invention can be produced, for example, by adding (A) an organic filler having liquid crystallinity, (B) an epoxy resin, and (C) an active ester compound, if necessary (D) an inorganic filler, if necessary (E) a radically polymerizable compound, if necessary (F) other curing agents, if necessary (G) a curing accelerator, if necessary (H) other additives, if necessary, and if necessary (K) an organic solvent in any order and/or all at once and mixing them in any preparation vessel. In addition, the temperature can be appropriately set in the process of adding and mixing each component, and heating and/or cooling may be performed temporarily or throughout. In addition, during or after the process of adding and mixing, the resin composition may be stirred or shaken using a stirring device or shaking device such as a mixer to disperse uniformly. In addition, degassing may be performed under low pressure conditions such as under vacuum at the same time as stirring or shaking.

<Characteristics of Resin Composition>
The resin composition of the present invention contains (A) an organic filler having liquid crystallinity, (B) an epoxy resin, and (C) an active ester compound. By using such a resin composition, it is possible to keep the dielectric tangent low even in a high-temperature environment such as 90° C., and to obtain a cured product having excellent crack resistance after desmearing, and preferably, to obtain a cured product having a low dielectric tangent even at room temperature such as 23° C. or at normal temperature.

The cured product of the resin composition of the present invention may have the characteristic of being able to suppress the occurrence of cracks after desmear treatment (roughening treatment). Therefore, in one embodiment, after producing a circuit board and performing a desmear treatment as in Test Example 2 below, when 100 copper pads on the circuit board are observed, the number of cracks may be preferably 10 or less (10% or less).

The cured product of the resin composition of the present invention may be characterized by a low dielectric tangent (Df) even in a high temperature environment such as 90°C. Therefore, in one embodiment, the dielectric tangent (Df) of the cured product of the resin composition when measured at 5.8 GHz and 90°C as in Test Example 1 below may be preferably 0.020 or less, 0.010 or less, more preferably 0.009 or less, 0.008 or less, even more preferably 0.007 or less, 0.006 or less, and particularly preferably 0.005 or less, 0.004 or less, 0.003 or less.

The cured product of the resin composition of the present invention may be characterized by a low dielectric loss tangent (Df) even at room temperature or normal temperature such as 23°C. Therefore, in one embodiment, the dielectric loss tangent (Df) of the cured product of the resin composition when measured at 5.8 GHz and 23°C as in Test Example 1 below may be preferably 0.020 or less, 0.010 or less, more preferably 0.009 or less, 0.008 or less, even more preferably 0.007 or less, 0.006 or less, even more preferably 0.005 or less, 0.004 or less, and particularly preferably 0.003 or less, 0.002 or less.

<Applications of the resin composition>
The resin composition of the present invention can be suitably used as a resin composition for insulating purposes, particularly as a resin composition for forming an insulating layer. Specifically, it can be suitably used as a resin composition for forming an insulating layer (resin composition for forming an insulating layer for forming a conductor layer) for forming a conductor layer (including a rewiring layer) formed on an insulating layer. In addition, in a printed wiring board described later, it can be suitably used as a resin composition for forming an insulating layer of a printed wiring board (resin composition for forming an insulating layer of a printed wiring board). The resin composition of the present invention can also be used in a wide range of applications requiring a resin composition, such as a resin sheet, a sheet-like laminate material such as a prepreg, a solder resist, an underfill material, a die bonding material, a semiconductor encapsulant, a hole filling resin, and a component embedding resin.

Furthermore, for example, when a semiconductor chip package is manufactured through the following steps (1) to (6), the resin composition of the present invention can be suitably used as a resin composition for a rewiring formation layer serving as an insulating layer for forming a rewiring layer (resin composition for forming a rewiring formation layer) and as a resin composition for sealing a semiconductor chip (resin composition for sealing a semiconductor chip). When a semiconductor chip package is manufactured, a rewiring layer may be further formed on the sealing layer.
(1) A step of laminating a temporary fixing film on a substrate;
(2) A step of temporarily fixing a semiconductor chip on a temporary fixing film;
(3) forming an encapsulation layer on the semiconductor chip;
(4) peeling the substrate and the temporary fixing film from the semiconductor chip;
(5) forming a rewiring formation layer as an insulating layer on the surface of the semiconductor chip from which the base material and the temporary fixing film have been peeled off; and (6) forming a rewiring layer as a conductor layer on the rewiring formation layer.

In addition, the resin composition of the present invention provides an insulating layer with good component embedding properties, so it can also be used suitably when the printed wiring board is a circuit board with built-in components.

<Sheet-like laminate material>
The resin composition of the present invention can be used by coating in the form of a varnish, but from an industrial perspective, it is generally preferred to use the resin composition in the form of a sheet-like laminate material containing the resin composition.

The following resin sheets and prepregs are preferred as sheet-like laminate materials.

In one embodiment, the resin sheet comprises a support and a resin composition layer provided on the support, and the resin composition layer is formed from the resin composition of the present invention.

The thickness of the resin composition layer is preferably 50 μm or less, more preferably 40 μm or less, from the viewpoint of making the printed wiring board thinner and being able to provide a cured product with excellent insulating properties even if the cured product of the resin composition is a thin film. The lower limit of the thickness of the resin composition layer is not particularly limited, but can usually be 5 μm or more, 10 μm or more, etc.

Examples of the support include films made of plastic materials, metal foils, and release paper, with films made of plastic materials and metal foils being preferred.

When a film made of a plastic material is used as the support, examples of the plastic material include polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter sometimes abbreviated as "PEN"), polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylics such as polymethyl methacrylate (PMMA), cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, polyimide, etc. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred, and inexpensive polyethylene terephthalate is particularly preferred.

When a metal foil is used as the support, examples of the metal foil include copper foil and aluminum foil, with copper foil being preferred. As the copper foil, a foil made of a single metal, copper, or an alloy of copper and another metal (e.g., tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.) may be used.

The support may be subjected to a matte treatment, corona treatment, or antistatic treatment on the surface that is to be bonded to the resin composition layer.

As the support, a support with a release layer having a release layer on the surface to be bonded to the resin composition layer may be used. Examples of the release agent used in the release layer of the support with a release layer include one or more release agents selected from the group consisting of alkyd resins, polyolefin resins, urethane resins, and silicone resins. The support with a release layer may be a commercially available product, such as "SK-1", "AL-5", and "AL-7" manufactured by Lintec Corporation, "Lumirror T60" manufactured by Toray Industries, "Purex" manufactured by Teijin Limited, and "Unipeel" manufactured by Unitika Limited, which are PET films having a release layer mainly composed of an alkyd resin-based release agent.

The thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, and more preferably in the range of 10 μm to 60 μm. When using a support with a release layer, it is preferable that the thickness of the entire support with the release layer is in the above range.

In one embodiment, the resin sheet may further include an optional layer as necessary. For example, such an optional layer may be a protective film similar to the support provided on the surface of the resin composition layer that is not bonded to the support (i.e., the surface opposite the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. By laminating the protective film, it is possible to suppress adhesion of dirt and the like and scratches on the surface of the resin composition layer.

The resin sheet can be produced, for example, by preparing a resin varnish by dissolving the liquid resin composition in an organic solvent or by applying the resin varnish onto a support using a die coater or the like, and then drying the varnish to form a resin composition layer.

The organic solvent may be the same as the organic solvent described as a component of the resin composition. The organic solvent may be used alone or in combination of two or more kinds.

Drying may be performed by known methods such as heating or blowing hot air. There are no particular limitations on the drying conditions, but drying is performed so that the content of organic solvent in the resin composition layer is 10% by mass or less, preferably 5% by mass or less. Although it varies depending on the boiling point of the organic solvent in the resin composition or resin varnish, for example, when using a resin composition or resin varnish containing 30% by mass to 60% by mass of organic solvent, the resin composition layer can be formed by drying at 50°C to 150°C for 3 to 10 minutes.

The resin sheet can be stored in a roll. If the resin sheet has a protective film, it can be used by peeling off the protective film.

In one embodiment, the prepreg is formed by impregnating a sheet-like fiber substrate with the resin composition of the present invention.

The sheet-like fiber substrate used for the prepreg is not particularly limited, and may be any commonly used substrate for prepregs, such as glass cloth, aramid nonwoven fabric, or liquid crystal polymer nonwoven fabric. From the viewpoint of making the printed wiring board thinner, the thickness of the sheet-like fiber substrate is preferably 50 μm or less, more preferably 40 μm or less, even more preferably 30 μm or less, and particularly preferably 20 μm or less. There is no particular lower limit to the thickness of the sheet-like fiber substrate. It is usually 10 μm or more.

Prepregs can be manufactured by known methods such as the hot melt method and the solvent method.

The thickness of the prepreg can be in the same range as the resin composition layer in the resin sheet described above.

The sheet-like laminate material of the present invention can be suitably used to form an insulating layer of a printed wiring board (for an insulating layer of a printed wiring board), and can be even more suitably used to form an interlayer insulating layer of a printed wiring board (for an interlayer insulating layer of a printed wiring board).

<Printed Wiring Board>
The printed wiring board of the present invention includes an insulating layer made of a cured product obtained by curing the resin composition of the present invention.

The printed wiring board can be produced, for example, by using the above-mentioned resin sheet by a method including the following steps (I) and (II).
(I) a step of laminating a resin sheet on an inner layer substrate so that a resin composition layer of the resin sheet is bonded to the inner layer substrate; and (II) a step of curing (e.g., thermally curing) the resin composition layer to form an insulating layer.

The "inner layer substrate" used in step (I) is a member that will be the substrate of the printed wiring board, and examples thereof include glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates. The substrate may have a conductor layer on one or both sides, and the conductor layer may be patterned. An inner layer substrate having a conductor layer (circuit) formed on one or both sides of the substrate may be called an "inner layer circuit substrate." In addition, intermediate products on which an insulating layer and/or a conductor layer is to be formed during the manufacture of a printed wiring board are also included in the "inner layer substrate" of the present invention. When the printed wiring board is a component-embedded circuit board, an inner layer substrate with a component embedded may be used.

The lamination of the inner layer substrate and the resin sheet can be carried out, for example, by heat-pressing the resin sheet to the inner layer substrate from the support side. Examples of the member for heat-pressing the resin sheet to the inner layer substrate (hereinafter also referred to as the "heat-pressing member") include a heated metal plate (such as a SUS panel) or a metal roll (SUS roll). Note that rather than pressing the heat-pressing member directly onto the resin sheet, it is preferable to press it via an elastic material such as heat-resistant rubber so that the resin sheet can sufficiently follow the surface irregularities of the inner layer substrate.

The lamination of the inner layer substrate and the resin sheet may be performed by a vacuum lamination method. In the vacuum lamination method, the heat-pressure bonding temperature is preferably in the range of 60°C to 160°C, more preferably in the range of 80°C to 140°C, the heat-pressure bonding pressure is preferably in the range of 0.098MPa to 1.77MPa, more preferably in the range of 0.29MPa to 1.47MPa, and the heat-pressure bonding time is preferably in the range of 20 seconds to 400 seconds, more preferably in the range of 30 seconds to 300 seconds. The lamination may be performed under reduced pressure conditions, preferably at a pressure of 26.7hPa or less.

Lamination can be performed using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include a vacuum pressure laminator manufactured by Meiki Seisakusho Co., Ltd., a vacuum applicator manufactured by Nikko Materials Co., Ltd., and a batch-type vacuum pressure laminator.

After lamination, the laminated resin sheets may be smoothed under normal pressure (atmospheric pressure), for example by pressing a heat-pressure bonding member from the support side. The pressing conditions for the smoothing treatment may be the same as the heat-pressure bonding conditions for the lamination. The smoothing treatment may be performed using a commercially available laminator. Note that lamination and smoothing treatment may be performed consecutively using the commercially available vacuum laminator.

The support may be removed between steps (I) and (II), or after step (II).

In step (II), the resin composition layer is cured (e.g., thermally cured) to form an insulating layer made of a cured product of the resin composition. The curing conditions for the resin composition layer are not particularly limited, and conditions that are typically used when forming an insulating layer for a printed wiring board may be used.

For example, the thermal curing conditions of the resin composition layer vary depending on the type of resin composition, but in one embodiment, the curing temperature is, for example, 120°C or higher, 130°C or higher, more than 130°C, 135°C or higher, more than 135°C, preferably 140°C or higher, more preferably 150°C or higher, even more preferably 170°C or higher, and for example, 240°C or lower, preferably 220°C or lower, more preferably 210°C or lower. The curing time can be preferably 5 minutes to 120 minutes, more preferably 10 minutes to 100 minutes, even more preferably 15 minutes to 100 minutes.

Before the resin composition layer is thermally cured, the resin composition layer may be preheated at a temperature lower than the curing temperature. For example, prior to thermally curing the resin composition layer, the resin composition layer may be preheated at a temperature of 50°C to 140°C, preferably 60°C to 135°C, and more preferably 70°C to 130°C for 5 minutes or more, preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes, and even more preferably 15 minutes to 100 minutes.

When manufacturing a printed wiring board, the steps of (III) drilling holes in the insulating layer, (IV) roughening the insulating layer, and (V) forming a conductor layer may be further carried out. These steps (III) to (V) may be carried out according to various methods known to those skilled in the art that are used in the manufacture of printed wiring boards. When the support is removed after step (II), the removal of the support may be carried out between steps (II) and (III), between steps (III) and (IV), or between steps (IV) and (V). Furthermore, the formation of the insulating layer and the conductor layer in steps (II) to (V) may be repeated as necessary to form a multilayer wiring board.

In another embodiment, the printed wiring board of the present invention can be manufactured using the above-mentioned prepreg. The manufacturing method is basically the same as when a resin sheet is used.

Step (III) is a step of drilling holes in the insulating layer, which allows holes such as via holes and through holes to be formed in the insulating layer. Step (III) may be performed using, for example, a drill, a laser, plasma, etc., depending on the composition of the resin composition used to form the insulating layer. The dimensions and shape of the holes may be appropriately determined depending on the design of the printed wiring board.

Step (IV) is a step of roughening the insulating layer. Usually, smears are also removed in this step (IV). The procedure and conditions of the roughening treatment are not particularly limited, and known procedures and conditions that are usually used when forming an insulating layer for a printed wiring board can be adopted. For example, the insulating layer can be roughened by carrying out a swelling treatment with a swelling liquid, a roughening treatment with an oxidizing agent, and a neutralization treatment with a neutralizing liquid in this order.

The swelling liquid used in the roughening treatment is not particularly limited, but includes an alkaline solution, a surfactant solution, etc., and is preferably an alkaline solution, and more preferably a sodium hydroxide solution or a potassium hydroxide solution. Examples of commercially available swelling liquids include "Swelling Dip Securigans P" and "Swelling Dip Securigans SBU" manufactured by Atotech Japan. The swelling treatment using the swelling liquid is not particularly limited, but can be performed by immersing the insulating layer in a swelling liquid at 30°C to 90°C for 1 to 20 minutes, for example. From the viewpoint of suppressing the swelling of the resin of the insulating layer to an appropriate level, it is preferable to immerse the insulating layer in a swelling liquid at 40°C to 80°C for 5 to 15 minutes.

The oxidizing agent used in the roughening treatment is not particularly limited, but examples thereof include an alkaline permanganate solution in which potassium permanganate or sodium permanganate is dissolved in an aqueous solution of sodium hydroxide. The roughening treatment using an oxidizing agent such as an alkaline permanganate solution is preferably performed by immersing the insulating layer in an oxidizing agent solution heated to 60°C to 100°C for 10 to 30 minutes. The concentration of permanganate in the alkaline permanganate solution is preferably 5% by mass to 10% by mass. Examples of commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact CP" and "Dosing Solution Securigans P" manufactured by Atotech Japan.

The neutralizing solution used in the roughening treatment is preferably an acidic aqueous solution, and a commercially available product such as "Reduction Solution Securigant P" manufactured by Atotech Japan is an example.

Treatment with a neutralizing solution can be carried out by immersing the surface that has been roughened with an oxidizing agent in a neutralizing solution at 30°C to 80°C for 5 to 30 minutes. From the standpoint of workability, etc., it is preferable to immerse the object that has been roughened with an oxidizing agent in a neutralizing solution at 40°C to 70°C for 5 to 20 minutes.

Step (V) is a step of forming a conductor layer, in which the conductor layer is formed on the insulating layer. There are no particular limitations on the conductor material used for the conductor layer.

In a preferred embodiment, the conductor layer contains one or more metals selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. The conductor layer may be a single metal layer or an alloy layer, and examples of the alloy layer include layers formed from alloys of two or more metals selected from the above group (e.g., nickel-chromium alloy, copper-nickel alloy, and copper-titanium alloy). Among these, from the viewpoints of versatility, cost, ease of patterning, etc. of the conductor layer formation, a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or an alloy layer of a nickel-chromium alloy, a copper-nickel alloy, or a copper-titanium alloy is preferred, a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or an alloy layer of a nickel-chromium alloy is more preferred, and a single metal layer of copper is even more preferred.

The conductor layer may be a single-layer structure, or a multi-layer structure in which two or more single metal layers or alloy layers made of different types of metals or alloys are laminated. When the conductor layer has a multi-layer structure, the layer in contact with the insulating layer is preferably a single metal layer of chromium, zinc, or titanium, or an alloy layer of a nickel-chromium alloy.

The thickness of the conductor layer depends on the desired printed wiring board design, but is generally between 3 μm and 35 μm, preferably between 5 μm and 30 μm.

In one embodiment, the conductor layer may be formed by plating. For example, a conductor layer having a desired wiring pattern can be formed by plating the surface of the insulating layer using a conventionally known technique such as a semi-additive method or a full-additive method, and from the viewpoint of ease of production, it is preferable to form the conductor layer by a semi-additive method. Below, an example of forming the conductor layer by a semi-additive method is shown.

First, a plating seed layer is formed on the surface of the insulating layer by electroless plating. Next, a mask pattern is formed on the formed plating seed layer to expose a portion of the plating seed layer corresponding to the desired wiring pattern. A metal layer is formed on the exposed plating seed layer by electrolytic plating, and the mask pattern is then removed. Thereafter, unnecessary plating seed layer is removed by etching or the like, and a conductor layer having the desired wiring pattern can be formed.

In another embodiment, the conductor layer may be formed using a metal foil. When the conductor layer is formed using a metal foil, it is preferable to perform step (V) between steps (I) and (II). For example, after step (I), the support is removed, and a metal foil is laminated on the exposed surface of the resin composition layer. The lamination of the resin composition layer and the metal foil may be performed by a vacuum lamination method. The lamination conditions may be the same as those described for step (I). Next, step (II) is performed to form an insulating layer. Thereafter, a conductor layer having a desired wiring pattern can be formed by a conventionally known technique such as a subtractive method or a modified semi-additive method using the metal foil on the insulating layer.

Metal foils can be manufactured by known methods such as electrolysis and rolling. Commercially available metal foils include HLP foil and JXUT-III foil manufactured by JX Nippon Mining & Metals Corporation, and 3EC-III foil and TP-III foil manufactured by Mitsui Mining & Smelting Co., Ltd.

<Semiconductor Device>
The semiconductor device of the present invention includes the printed wiring board of the present invention. The semiconductor device of the present invention can be manufactured using the printed wiring board of the present invention.

Semiconductor devices include various semiconductor devices used in electrical appliances (e.g., computers, mobile phones, digital cameras, and televisions) and vehicles (e.g., motorcycles, automobiles, trains, ships, and aircraft).

The present invention will be specifically explained below with reference to examples. The present invention is not limited to these examples. In the following, "parts" and "%" representing amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified. Unless otherwise specified, the temperature condition is room temperature (25°C).

Synthesis Example 1: Synthesis of Liquid Crystal Polymer
A polymerization vessel equipped with a stirring blade was charged with 60 mol % of 6-hydroxy-2-naphthoic acid (HNA), 20 mol % of 4,4-dihydroxybiphenyl (BP), 15.5 mol % of terephthalic acid (TPA), and 4.5 mol % of 2,6-naphthalenedicarboxylic acid (NADA), and potassium acetate and magnesium acetate were charged as catalysts. The polymerization vessel was reduced in pressure and nitrogen was injected three times to replace with nitrogen, and then acetic anhydride (1.08 molar equivalent relative to the hydroxyl group) was further added. The temperature was raised to 150° C., and an acetylation reaction was carried out under reflux for 2 hours.

After the acetylation was completed, the polymerization vessel in which acetic acid was being distilled was heated at a rate of 0.5°C/min, and when the temperature of the melt in the vessel reached 310°C, the polymer was removed and cooled to solidify. The resulting polymer was pulverized to a size that could pass through a sieve with 2.0 mm openings to obtain a prepolymer.

The prepolymer obtained above was then heated from room temperature to 310°C over 14 hours using a heater in an oven manufactured by Yamato Scientific Co., Ltd., and the temperature was then maintained at 310°C for 1 hour to carry out solid-phase polymerization. The liquid crystal polymer A was then allowed to naturally dissipate heat at room temperature, yielding liquid crystal polymer A. Using a polarizing microscope manufactured by Olympus Corporation (product name: BH-2) equipped with a microscope hot stage manufactured by Mettler (product name: FP82HT), liquid crystal polymer A was heated and melted on the microscope heating stage, and the presence or absence of optical anisotropy was used to confirm that it exhibited liquid crystallinity.

<Preparation Example 1: Production of Liquid Crystal Polymer Particles>
The powder of liquid crystal polymer A synthesized above was continuously pulverized using an apparatus consisting of a Nippon Pneumatic Mfg. Co., Ltd. SPK-12 jet mill combined with a Nippon Pneumatic Mfg. Co., Ltd. DSF-10 classifier under conditions of a pulverization pressure of 0.65 MPa and a resin supply rate of 5 kg/h to obtain liquid crystal polymer particles A.

<Evaluation of Liquid Crystal Polymer Particles>
(Melt point measurement)
The melting point of the liquid crystal polymer particles A obtained above was measured by a differential scanning calorimeter (DSC) manufactured by Hitachi High-Tech Science Co., Ltd. in accordance with the test methods of ISO11357 and ASTM D3418. At this time, the temperature was raised from room temperature to 360-380°C at a heating rate of 10°C/min to completely melt the polymer, then the temperature was lowered to 30°C at a rate of 10°C/min, and the temperature was further raised to 380°C at a rate of 10°C/min, and the apex of the endothermic peak obtained when this was taken as the melting point. The measured melting point was 319°C.

(Measurement of particle size distribution)
The particle size distribution of the liquid crystal polymer particles A obtained above was measured using a laser diffraction/scattering particle size distribution measuring device (manufactured by Beckman Coulter, LS 13 320 dry system, equipped with a Tornado dry powder module). The parameters D50, D90 and Dp, which indicate the particle size distribution, were obtained as calculation results from the measurement data. As a result, D50 was 4.8 μm and D90/D50 was 1.7.

(Measurement of dielectric tangent (10 GHz))
The liquid crystal polymer particles A obtained above were heated and melted under conditions of melting point to melting point + 30°C, and injection molded using a mold of 30 mm x 30 mm x 0.4 mm (thickness) to prepare a flat test piece. Next, the flat test piece was used to measure the dielectric loss tangent at a frequency of 10 GHz by split post dielectric resonator method (SPDR method) using a network analyzer N5247A from Keysight Technologies. Note that, N=4 samples of each type were measured, and the dielectric loss tangent calculated as the average value of the four measurements was 0.0007.

(Outgassing Measurement)
The liquid crystal polymer particles A obtained above were placed in a 20 ml vial and sealed, and then heat-treated at 190° C. for 1 hour. The amount of acetic acid and other gases (phenol, phenyl acetate, etc.) generated during the heat treatment was quantified by a gas chromatograph (HP7820A) connected to a headspace sampler (HP7697A) manufactured by Hewlett-Packard. A G-100 (40 m) manufactured by Chemical Inspection Association was used as the column, and other conditions were an initial temperature of 45° C., a heating rate of 20° C./min, a final temperature of 280° C., a helium pressure of 8.3 psi, and a split ratio of 2.0, and measurements were performed using an FID detector. The amount of acetic acid measured as outgas was 0.4 ppm, and the amount of other outgass was 5.8 ppm.

<Examples 1 to 8 and Comparative Example 1: Preparation of Resin Varnish>
[Example 1]
Naphthalene type epoxy resin (DIC Corporation "HP-4032-SS", epoxy equivalent 144 g / eq.) 15 parts, active ester type curing agent ("HPC-8150-62T", active group equivalent 229 g / eq., toluene solution with non-volatile content of 61.5% by mass) 43 parts, other curing agent (phenol type curing agent, DIC Corporation "LA-3018-50P", hydroxyl group equivalent 151 g / eq., 1-methoxy 2-propanol solution with non-volatile content of 50% by mass) 5 parts, liquid crystal polymer powder A as component (A) 2 parts, inorganic filler (amine-based alkoxysilane compound (Shin-Etsu Chemical Co., Ltd. "KBM573") surface-treated spherical silica (Admatechs Co., Ltd., "SO-C2", average particle size 0.5 μm, specific surface area 5.8 m ² A resin varnish was obtained by mixing 125 parts of the curing agent (1B2PZ, manufactured by Shikoku Chemical Industry Co., Ltd.), 0.5 parts of a curing accelerator (1B2PZ, manufactured by Shikoku Chemical Industry Co., Ltd.), 10 parts of MEK, and 10 parts of cyclohexanone and dispersing the mixture uniformly using a high-speed rotating mixer.

[Example 2]
In Example 1, 2 parts of an MEK solution (62% by mass of non-volatile components) of maleimide compound A (Mw/Mn=1.81, t''=1.47 (mainly 1, 2 or 3)) represented by the following formula (M) synthesized by the method described in Synthesis Example 1 of Japan Institute of Invention and Innovation Disclosure Technical Journal No. 2020-500211 was further used. A resin varnish was obtained in the same manner as in Example 1, except for the above-mentioned points.

[Example 3]
A resin varnish was obtained in the same manner as in Example 1, except that 2 parts of another maleimide compound ("MIR-5000-60T" manufactured by Nippon Kayaku Co., Ltd., a toluene solution with a non-volatile content of 60% by mass) was added.

[Example 4]
A resin varnish was obtained in the same manner as in Example 1, except that 2 parts of another maleimide compound ("MIR-3000-70MT" manufactured by Nippon Kayaku Co., Ltd., a toluene/MEK mixed solution with a non-volatile content of 70% by mass) was added.

[Example 5]
A resin varnish was obtained in the same manner as in Example 1, except that 2 parts of another maleimide compound ("BMI-689" manufactured by Designer Molecules, Inc.) was added.

[Example 6]
A resin varnish was obtained in the same manner as in Example 1, except that 2 parts of another compound having a double bond ("OPE-2St-1200" manufactured by Mitsubishi Gas Chemical Co., Ltd., a toluene solution with a nonvolatile content of 65% by mass) was added.

[Example 7]
A resin varnish was obtained in the same manner as in Example 1, except that the amount of liquid crystal polymer powder A as component (A) was changed from 2 parts to 1 part.

[Example 8]
A resin varnish was obtained in the same manner as in Example 1, except that the amount of liquid crystal polymer powder A as component (A) was changed from 2 parts to 4 parts.

[Comparative Example 1]
A resin varnish was obtained in the same manner as in Example 1, except that 2 parts of the liquid crystal polymer powder A as the component (A) was not added.

<Production Example 1: Production of resin sheet A having a resin composition layer thickness of 40 μm>
A polyethylene terephthalate film with a release layer ("AL5" manufactured by Lintec Corporation, thickness 38 μm) was prepared as a support. On the release layer of this support, the resin varnish obtained in the examples and comparative examples was uniformly applied so that the thickness of the resin composition layer after drying was 40 μm. Thereafter, the resin composition was dried at 80° C. to 100° C. (average 90° C.) for 4 minutes to obtain a resin sheet A including a support and a resin composition layer.

<Test Example 1: Measurement of dielectric tangent>
The resin sheet A obtained in Production Example 1 was cured for 90 minutes in an oven at 190° C. using the resin varnish obtained in the Examples and Comparative Examples. The support was peeled off from the resin sheet A taken out of the oven to obtain a cured product of the resin composition layer. The cured product was cut into a length of 80 mm and a width of 2 mm to be used as a cured product for evaluation.

For each evaluation cured product, the dielectric tangent (Df) was measured by the cavity resonance perturbation method using an Agilent Technologies HP8362B at a measurement frequency of 5.8 GHz and measurement temperatures of 23°C and 90°C. Measurements were performed on two test pieces, and the average was calculated.

<Production Example 2: Production of resin sheet B having a resin composition layer thickness of 25 μm>
A polyethylene terephthalate film with a release layer ("AL5" manufactured by Lintec Corporation, thickness 38 μm) was prepared as a support. The resin varnish obtained in the examples and comparative examples was uniformly applied onto the release layer of this support so that the thickness of the resin composition layer after drying was 25 μm, and dried at 70° C. to 80° C. (average 75° C.) for 2.5 minutes to obtain a resin sheet B including a support and a resin composition layer.

<Test Example 2: Evaluation of crack resistance after desmear treatment>
The 25 μm thick resin sheet B produced in Production Example 2 was laminated on both sides of a core material (Hitachi Chemical Co., Ltd. "E705GR", thickness 400 μm) in which circular copper pads (copper thickness 35 μm) with a diameter of 350 μm were formed in a grid shape at intervals of 400 μm so that the residual copper rate was 60%. Using a batch type vacuum pressure laminator (Nikko Materials Co., Ltd. two-stage build-up laminator "CVP700"), the resin composition layer was bonded to the inner layer substrate. This lamination was performed by decompressing for 30 seconds to an atmospheric pressure of 13 hPa or less, and then pressing for 30 seconds at a temperature of 100 ° C and a pressure of 0.74 MPa. This was placed in a 130 ° C oven and heated for 30 minutes, and then transferred to a 170 ° C oven and heated for 30 minutes. The support was then peeled off, and the resulting circuit board was immersed in swelling dip Securigant P (Atotech Japan Co., Ltd.), which is a swelling liquid, at 60° C. for 10 minutes. Next, the circuit board was immersed in Concentrate Compact P (aqueous solution of KMnO ₄ : 60 g/L, NaOH: 40 g/L) (Atotech Japan Co., Ltd.), which is a roughening liquid, at 80° C. for 30 minutes. Finally, the circuit board was immersed in Reduction Solution Securigant P (Atotech Japan Co., Ltd.), which is a neutralizing liquid, at 40° C. for 5 minutes. 100 copper pads of the circuit board after the roughening treatment were observed to confirm the presence or absence of cracks in the resin composition layer. If there were 10 or less cracks, it was marked as "◯", and if there were more than 10 cracks, it was marked as "X".

The amounts (parts by mass) of components (A) to (G) used, including volatile components, in the resin compositions of the Examples and Comparative Examples, and the measurement results of the Test Examples are shown in the following Table 1. In Table 1, the non-volatile content (% by mass) of each component is shown in the "N.V." column.

From the above, it was found that by using a resin composition containing (A) an organic filler having liquid crystallinity, (B) an epoxy resin, and (B) an active ester compound, it is possible to obtain a cured product that has a low dielectric tangent (Df) even in a high-temperature environment such as 90°C and has excellent crack resistance after desmearing. It was also found that this cured product has a low dielectric tangent (Df) even at room temperature or normal temperature such as 23°C.

Claims (11)

A resin composition comprising (A) an organic filler having liquid crystal properties, (B) an epoxy resin, and (C) an active ester compound. The resin composition according to claim 1, wherein the content of component (A) is 0.1% by mass or more and 10% by mass or less, when the resin components in the resin composition are taken as 100% by mass. The resin composition according to claim 1, wherein (A) the organic filler having liquid crystal properties has a melting point of 270°C or higher. The resin composition according to claim 1, further comprising (D) an inorganic filler. The resin composition according to claim 1, further comprising (E) a radically polymerizable compound. The resin composition according to claim 1, which is used to form an interlayer insulating layer of a printed wiring board. A cured product of the resin composition according to any one of claims 1 to 6. A sheet-like laminate material containing the resin composition according to any one of claims 1 to 6. A resin sheet having a support and a resin composition layer formed from the resin composition according to any one of claims 1 to 6 provided on the support. A printed wiring board having an insulating layer made of a cured product of the resin composition according to any one of claims 1 to 6. A semiconductor device including the printed wiring board according to claim 10.