Resin composition for circuit board formation and application of the same

Abstract

To provide a resin composition for circuit board formation from which a cured product that is excellent in moldability and in a high dielectric constant can be obtained.SOLUTION: A resin composition for circuit board formation contains (A) a high dielectric filler, and (B) a thermosetting resin, wherein (A) the high dielectric filler is one or two or more kinds selected from the group consisting of barium titanate, calcium titanate, storontium titanate, magnesium titanate, bismuth titanate, zirconium titanate, zinc titanate, magnesium zirconate, strontium zirconate, barium zirconate, calcium titanate zirconate, lead zirconate titanate, barium niobate magnesium, and calcium zirconate, and (B) the thermosetting resin is one or two or more kinds selected from the group consisting of an epoxy resin, a benzoxazine resin, a cyanate resin, a BT resin, a bismaleimide resin, a phenol resin, a polyimide resin, a melamine resin and an acrylic resin.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition for forming a circuit board and its use. [Background technology]

[0002] Conventionally, as the dielectric constant of antenna materials (dielectric substrates) built into semiconductor substrates and communication devices increases, further miniaturization can be achieved, and therefore substrates with excellent high dielectric constants are required.

[0003] Semiconductor devices with a structure in which an LSI and a capacitor are mounted on a circuit board are also known. However, in recent years, the drive voltage of LSIs has been decreasing, and voltage fluctuations can cause malfunctions and noise. Therefore, extremely high power integrity is required for the power supply voltage, and as a countermeasure, bypass capacitors (decoupling capacitors) are adopted. This allows the AC component of noise to be bypassed to the ground side, enabling voltage stabilization. Therefore, substrates with excellent high dielectric constants are required.

[0004] Patent Document 1 discloses a resin composition containing an epoxy resin, a phenolic resin curing agent, a curing accelerator, and barium titanate. Patent Document 2 discloses a resin composition containing a thermosetting resin, a titanium-based inorganic filler, and an inorganic filler having a lower dielectric constant than the titanium-based inorganic filler.

[0005] Patent Document 3 discloses a resin composition containing a dielectric powder containing one or more selected from the group consisting of titanium dioxide, barium titanate, calcium titanate, and strontium titanate, a cyanate ester compound, and an epoxy compound. Patent Document 4 discloses a resin composition containing a specified polyphenylene ether compound, a curing agent, a titanate compound filler, and a silica filler, in which the titanate compound filler and silica filler content ratio is within a specified range. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2018-141052 [Patent Document 2] Japanese Patent Publication No. 2023-013229 [Patent Document 3] International Publication No. 2023 / 074484 [Patent Document 4] International Publication No. 2022 / 202347 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the conventional techniques described in Patent Documents 1 to 4, there is room for improvement in moldability, such as the generation of voids during molding. That is, in the conventional techniques, the balance between high dielectric constant and moldability is poor, and there is room for improvement in this respect. [Means for solving the problem]

[0008] The present inventors have discovered that a specific combination of a high dielectric filler and a thermosetting resin can provide a cured product that is excellent in moldability and high in dielectric constant, and have completed the present invention. That is, the present invention can be shown as follows.

[0009] [1] (A) a high dielectric filler; (B) a thermosetting resin; A resin composition for forming a circuit board, comprising: (A) the high dielectric filler is one or more selected from the group consisting of barium titanate, calcium titanate, strontium titanate, magnesium titanate, bismuth titanate, zirconium titanate, zinc titanate, magnesium zirconate, strontium zirconate, barium zirconate, calcium titanate zirconate, lead titanate zirconate, barium magnesium niobate, and calcium zirconate; (B) A resin composition for forming a circuit board, wherein the thermosetting resin is one or more selected from the group consisting of epoxy resins, benzoxazine resins, cyanate resins, bismaleimide triazine resins, maleimide resins, phenolic resins, polyimide resins, and melamine resins. [2] The resin composition for forming a circuit board according to [1], wherein the highly dielectric filler (A) has an amino-based silane group on its surface. [3] The resin composition for forming a circuit board according to [2], wherein the high dielectric filler (A) is a phenylaminosilane-treated high dielectric filler. [4] The resin composition for forming a circuit board according to [3], wherein the phenylaminosilane-treated high dielectric filler comprises one or more selected from barium titanate, calcium titanate, and strontium titanate, all of which have been treated with phenylaminosilane. [5] The resin composition for forming a circuit board according to [3] or [4], wherein the average particle size of the phenylaminosilane-treated high dielectric filler is 0.1 μm or more and 3 μm or less. [6] The resin composition for forming a circuit board according to any one of [3] to [5], wherein the phenylaminosilane-treated high dielectric filler contains two or more types of phenylaminosilane-treated high dielectric fillers having different average particle sizes. [7] The resin composition for forming circuit boards according to any one of [1] to [6], wherein the thermosetting resin (B) contains a benzoxazine resin. [8] The resin composition for forming a circuit board according to any one of [1] to [7], further comprising a phenoxy resin. [9] The resin composition for forming a circuit board according to any one of [1] to [8], A resin composition for forming a circuit board, comprising the phenoxy resin in an amount of 0.1 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the resin composition for forming a circuit board.

[10] The resin composition for forming a circuit board according to any one of [1] to [9], wherein the flow rate measured under the following conditions is 5% or more and 50% or less. (conditions) The resin composition for forming circuit boards was applied to one side of a 38 μm-thick PET film using a comma coater so that the dried resin layer would be 30 μm thick. This was then dried for 3 minutes in a dryer at 160°C to obtain a resin sheet (resin film with carrier) in which a resin film was laminated on a PET film. The resin sheet was then cut out to prepare test pieces with a diameter of 113 mm. The weight of the PET film was subtracted from the total weight of the four test pieces to calculate the weight of the resin film alone (mass: W0). The four test pieces were stacked together to form a laminate, which was then sandwiched between aluminum foil on both sides and heated and pressurized for 5 minutes at 170°C and 1.5 MPa in a top-bottom press. The resin composition that flowed out of the laminate was removed, and the weight of the PET film was subtracted from the weight of the laminate after testing to calculate the weight of the resin film alone contained in the laminate after testing (mass: W1). The flow rate (%) of the resin composition is calculated using the following formula. Formula: [(W0-W1) / W0]×100

[11] A resin sheet made of the resin composition for forming a circuit board according to any one of [1] to

[10] .

[12] A carrier substrate; A resin film with a carrier, comprising: a resin sheet formed on the carrier base and made of the resin composition for forming a circuit board according to any one of [1] to

[10] .

[13] A prepreg obtained by impregnating a fiber base material with the resin composition for forming a circuit board according to any one of [1] to

[10] .

[14] A laminate comprising the prepreg according to

[13] above and a metal layer disposed on at least one surface thereof.

[15] A printed wiring board having an insulating layer made of a cured product of the resin composition for forming a circuit board according to any one of [1] to

[10] .

[16] An insulating substrate made of a cured product of the resin composition for forming a circuit board according to any one of [1] to

[10] ; a capacitor embedded in the insulating substrate; a semiconductor element mounted on the insulating substrate or embedded in the insulating substrate and electrically connected to the capacitor; A semiconductor device comprising:

[17] A coreless substrate having a build-up layer including an insulating layer formed of a cured product of the resin composition for forming a circuit board according to any one of [1] to

[10] , and a circuit layer. [Effects of the Invention]

[0010] According to the present invention, there is provided a resin composition for forming a circuit board that can give a cured product having excellent moldability and a high dielectric constant. In other words, the resin composition for forming a circuit board of the present invention has an excellent balance of these properties. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a cross-sectional view showing an example of the configuration of a resin film with a carrier in the present embodiment. [Figure 2] 1 is a cross-sectional view showing an example of a semiconductor package according to an embodiment of the present invention. [Figure 3] 1A to 1C are cross-sectional views showing steps in an example of a manufacturing process for a coreless substrate according to the present embodiment. [Figure 4] 1 shows a photograph (top) of the surface of a sample after a moldability test in Examples 1 to 4, and a photograph (bottom) of a cross section of the sample after the test taken with a scanning electron microscope. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all drawings, similar components are denoted by similar reference numerals, and their description will be omitted where appropriate. For example, "1 to 10" represents "1 or more" to "10 or less" unless otherwise specified.

[0013] The resin composition for forming a circuit board of this embodiment contains a high dielectric filler (A) and a thermosetting resin (B).

[0014] [High dielectric filler (A)] The highly dielectric filler (A) is one or more selected from the group consisting of barium titanate, calcium titanate, strontium titanate, magnesium titanate, bismuth titanate, zirconium titanate, zinc titanate, magnesium zirconate, strontium zirconate, barium zirconate, calcium titanate zirconate, lead titanate zirconate, barium magnesium niobate, and calcium zirconate. The resin composition for forming a circuit board of this embodiment contains the high dielectric filler (A), and thus can give a cured product with an excellent high dielectric constant. In this embodiment, the high dielectric filler (A) is preferably one or more selected from barium titanate, calcium titanate, and strontium titanate, which allows a cured product with an even higher dielectric constant to be obtained.

[0015] The shape of the high dielectric filler (A) may be granular, amorphous, flake-like, etc., and high dielectric fillers of these shapes can be used in any ratio. The average particle size of the high dielectric filler can be preferably 0.1 μm or more and 50 μm or less, more preferably 0.2 μm or more and 20 μm or less, and even more preferably 0.3 μm or more and 10 μm or less. This makes it possible to obtain a cured product that has excellent moldability and flowability as well as a high dielectric constant. The average particle size (median size) can be measured on a volume basis using, for example, a laser diffraction / scattering particle size distribution measuring device.

[0016] The content of the high dielectric filler (A) is preferably 40 to 95 mass % relative to the total solid mass of the resin composition for forming a circuit board, more preferably 50 to 90 mass %, and even more preferably 60 to 85 mass %. By setting the content of the high dielectric filler (A) to the above lower limit or more, it is possible to provide a cured resin film with a particularly high dielectric constant while maintaining impregnation properties. On the other hand, by setting the content of the high dielectric filler (A) to the above upper limit or less, it is possible to reduce the viscosity of the resin composition, which makes it easier to improve moldability and impregnation properties.

[0017] The highly dielectric filler (A) preferably has amino-based silane groups on its surface. It is believed that providing amino-based silane groups on the surface of the high dielectric filler (A) improves the compatibility between the high dielectric filler (A) and the thermosetting resin (B). A resin composition for forming circuit boards containing a high dielectric filler (A) with amino-based silane groups has excellent moldability, and a resin sheet made from this composition has excellent ability to fill gaps in circuits, etc. Furthermore, when molded under heat and pressure, the resin component and the high dielectric filler flow without separating, suppressing the occurrence of areas where the resin component is highly concentrated, resulting in excellent product yield.

[0018] The high dielectric filler (A) having an amino-based silane group can be obtained by treating the surface of the high dielectric filler with a phenylaminosilane compound. For example, it can be obtained by mixing 100 parts by mass of a high dielectric filler with 0.1 to 5 parts by mass of a phenylaminosilane compound, followed by heat treatment at 30 to 80° C. for about 0.1 to 1 hour. Furthermore, it is possible to obtain only single particles by passing the mixture through a sieve.

[0019] As the phenylaminosilane compound, for example, a phenylaminosilane compound represented by the following general formula (I) can be used.

[0020] [ka]

[0021] In the above formula (I), R 1 is a divalent hydrocarbon group having 1 to 12 carbon atoms, R 2represents hydrogen or a monovalent hydrocarbon group having 1 to 10 carbon atoms, X represents OCH3, OC2H5, or OC3H7, and m represents an integer of 0 to 5. When there are multiple Xs and when there are multiple R 2 may be the same or different from each other. In this embodiment, from the viewpoint of the above effects, R 1 is a propylene group or an octylene group, R 2 Preferably, each of X is a hydrogen atom and X is a methoxy group.

[0022] Examples of phenylaminosilane compounds include N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminoethyltrimethoxysilane, N-phenyl-3-aminopentyltrimethoxysilane, N-phenyl-3-aminohexyltrimethoxysilane, N-phenyl-3-aminoheptyltrimethoxysilane, N-phenyl-3-aminooctyltrimethoxysilane, N-phenyl-3-aminononyltrimethoxysilane, N-phenyl-3-aminodecyltrimethoxysilane, N-phenyl-3-aminoundecyltrimethoxysilane, and N-phenyl-3-aminododecyltrimethoxysilane. As the phenylaminosilane compound, it is preferable to use N-phenyl-3-aminopropyltrimethoxysilane or N-phenyl-3-aminooctyltrimethoxysilane from the viewpoint of the above effects.

[0023] From the viewpoint of the above-mentioned effects, the phenylaminosilane-treated high dielectric filler preferably contains one or more selected from phenylaminosilane-treated barium titanate, phenylaminosilane-treated calcium titanate, and phenylaminosilane-treated strontium titanate, and more preferably contains phenylaminosilane-treated barium titanate.

[0024] The average particle size of the phenylaminosilane-treated high dielectric filler can be preferably 0.1 μm or more and 3 μm or less, more preferably 0.2 μm or more and 2 μm or less, and even more preferably 0.3 μm or more and 1.5 μm or less. By having the average particle size in the above range, the high dielectric constant is excellent and moldability is also excellent. The average particle size (median size) can be measured on a volume basis using, for example, a laser diffraction / scattering particle size distribution measuring device.

[0025] The content of the phenylaminosilane-treated high dielectric filler is preferably 40 to 95 mass % relative to the total solid mass of the resin composition for forming circuit boards, more preferably 50 to 90 mass %, and even more preferably 60 to 85 mass %. By setting the content of barium titanate to the above lower limit or more, the cured resin film can have a particularly high dielectric constant while maintaining impregnation properties. On the other hand, by setting the content of phenylaminosilane-treated high dielectric filler to the above upper limit or less, the viscosity of the resin composition can be reduced, and moldability and impregnation properties can be easily improved.

[0026] The high dielectric filler (A) preferably contains two or more types of phenylaminosilane-treated high dielectric fillers with different average particle sizes. This allows for the production of a cured product with excellent moldability and a high dielectric constant. The two or more types of phenylaminosilane-treated high dielectric fillers with different average particle sizes may be the same type of phenylaminosilane-treated high dielectric filler, or a combination of different types of phenylaminosilane-treated high dielectric fillers. For example, when two types of phenylaminosilane-treated high dielectric fillers a and b having different average particle sizes are included, the average particle size of the phenylaminosilane-treated high dielectric filler a is smaller than the average particle size of the phenylaminosilane-treated high dielectric filler b, The average particle size of the phenylaminosilane-treated high dielectric filler a is preferably 0.1 μm or more and 1 μm or less, more preferably 0.2 μm or more and 0.8 μm or less, The average particle size of the phenylaminosilane-treated high dielectric filler b can be preferably 0.5 μm or more and 3 μm or less, and more preferably 0.8 μm or more and 2 μm or less.

[0027] The mass ratio (a:b) of the phenylaminosilane-treated high dielectric fillers a and b can be preferably 10:90 to 90:10, more preferably 10:90 to 50:50. By including them in this mass ratio, better moldability is achieved.

[0028] In this embodiment, the high dielectric filler (A) may contain other high dielectric fillers in addition to the phenylaminosilane-treated high dielectric filler.

[0029] [Thermosetting resin (B)] The thermosetting resin (B) is one or more selected from the group consisting of epoxy resins, benzoxazine resins, cyanate resins, bismaleimide triazine resins, maleimide resins, phenolic resins, polyimide resins, and melamine resins.

[0030] In this embodiment, the thermosetting resin (B) preferably contains one or more selected from the group consisting of epoxy resins, benzoxazine resins, cyanate resins, bismaleimide triazine resins, and maleimide resins, more preferably contains one or more selected from the group consisting of epoxy resins and benzoxazine resins, and even more preferably contains a benzoxazine resin.

[0031] The resin composition for forming a circuit board of this embodiment contains the thermosetting resin (B) together with the high dielectric filler (A), and therefore a cured product having excellent moldability and a high dielectric constant can be obtained.

[0032] (epoxy resin) The epoxy resin may be any monomer, oligomer, or polymer having two or more epoxy groups in one molecule, and there are no limitations on the molecular weight or molecular structure.

[0033] In this embodiment, examples of the epoxy resin include biphenyl-type epoxy resins; bisphenol-type epoxy resins such as bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, and tetramethylbisphenol F-type epoxy resins; stilbene-type epoxy resins; novolac-type epoxy resins such as phenol novolac-type epoxy resins and cresol novolac-type epoxy resins; multifunctional epoxy resins such as triphenolmethane-type epoxy resins and alkyl-modified triphenolmethane-type epoxy resins; aralkyl-type epoxy resins such as phenol aralkyl-type epoxy resins having a phenylene skeleton, phenol aralkyl-type epoxy resins having a biphenylene skeleton, and biphenyl aralkyl-type epoxy resins; naphthol-type epoxy resins such as dihydroxynaphthalene-type epoxy resins and epoxy resins obtained by glycidyl etherifying a dihydroxynaphthalene dimer; triazine-nucleus-containing epoxy resins such as triglycidyl isocyanurate and monoallyl diglycidyl isocyanurate; and bridged cyclic hydrocarbon compound-modified phenol-type epoxy resins such as dicyclopentadiene-modified phenol-type epoxy resins. These may be used alone or in combination of two or more.

[0034] Among these, from the viewpoint of low elastic modulus, the epoxy resin preferably contains one or more types selected from the group consisting of phenol aralkyl epoxy resins, biphenyl epoxy resins, bisphenol epoxy resins, novolac epoxy resins, and triphenolmethane epoxy resins, and more preferably contains one or more types selected from the group consisting of phenol aralkyl epoxy resins represented by the following general formula (1), biphenyl epoxy resins represented by the following general formula (2), and bisphenol epoxy resins represented by the following general formula (3).

[0035] [ka]

[0036] In formula (1), Ar 1represents a phenylene group or a naphthylene group, and Ar 1 When Ar is a naphthylene group, the glycidyl ether group may be bonded to either the α-position or the β-position. 2 represents any one of a phenylene group, a biphenylene group, and a naphthylene group. a and R b each independently represents a hydrocarbon group having 1 to 10 carbon atoms, g is an integer of 0 to 5, and h is an integer of 0 to 8. n 3 represents the degree of polymerization, and its average value is 1 to 3. In this embodiment, Ar 1 represents a phenylene group, and Ar 2 represents a biphenylene group, and g and h are 0, it is more preferable that the epoxy resin is a biphenylaralkyl type epoxy resin.

[0037] [ka]

[0038] In formula (2), there are multiple R c each independently represents a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms. 5 represents the degree of polymerization, and its average value is 0 to 4.

[0039] [ka]

[0040] In formula (3), there are multiple R d and R e each independently represents a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms. 6 represents the degree of polymerization, and its average value is 0 to 4. In this embodiment, there are multiple R d represents a hydrogen atom, and multiple R e represents a methyl group, a bisphenol F type epoxy resin is more preferred.

[0041] The epoxy resin may be contained in an amount of preferably 1 to 20% by mass, more preferably 2 to 15% by mass, and even more preferably 3 to 10% by mass, based on the total solid content of the resin composition for forming a circuit board of this embodiment. By setting the content of the epoxy resin to be equal to or greater than the above-mentioned lower limit, a high dielectric constant can be obtained. On the other hand, by setting the content of the epoxy resin to be equal to or less than the above-mentioned upper limit, an increase in viscosity can be suppressed, and good moldability and impregnation properties can be obtained.

[0042] (benzoxazine resin) The benzoxazine resin of this embodiment is a (co)polymer (ring-opening polymer) of a compound having two or more benzoxazine rings. Resin compositions for forming circuit boards containing benzoxazine resins have excellent moldability, and resin sheets made from these compositions are excellent at filling gaps in circuits, etc. Furthermore, when molded under heat and pressure, the resin component and the high-dielectric filler flow without separating, thereby suppressing the occurrence of regions where the resin component is present in high concentration, resulting in excellent product yield.

[0043] From the viewpoint of improving heat resistance, the compound having two or more benzoxazine rings can include, for example, at least one of a compound represented by the following general formula (4) and a compound represented by the following general formula (5), and preferably includes at least a compound represented by the following general formula (4).

[0044] [ka]

[0045] In the general formula (4), R3 is a divalent organic group having 1 to 30 carbon atoms, and may contain one or more of an oxygen atom and a nitrogen atom. From the viewpoint of improving the high-temperature storage characteristics of the circuit board, R3 is preferably a divalent organic group containing an aromatic ring. In this embodiment, the compound represented by the general formula (4) may be, for example, a compound represented by the following formula (4a):

[0046] [ka]

[0047] [ka]

[0048] In the general formula (5), R4 is a divalent organic group having 1 to 30 carbon atoms, and may contain one or more of an oxygen atom, a nitrogen atom, and a sulfur atom. Two R5 are each independently an aromatic hydrocarbon group having 1 to 12 carbon atoms.

[0049] The content of the benzoxazine resin is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more, based on the total amount of the resin composition for forming a circuit board (solid content). By making the content of the benzoxazine resin equal to or more than the above lower limit, a high dielectric constant can be obtained.

[0050] On the other hand, the content of the benzoxazine resin is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, based on the total amount of the resin composition for forming a circuit board (solid content). By setting the content of the benzoxazine resin to the above upper limit or less, the cured product of the resin composition for forming a circuit board can be maintained with good elasticity, while obtaining good moldability and embeddability.

[0051] [Cyanate resin] The cyanate resin is preferably an aromatic cyanate resin, and specific examples thereof include novolac cyanate resins such as phenol novolac and cresol novolac; aralkyl cyanate resins such as phenyl aralkyl, biphenyl aralkyl, and naphthalene aralkyl; and bisphenol cyanate resins such as bisphenol A cyanate resin, bisphenol E cyanate resin, and tetramethyl bisphenol F cyanate resin.

[0052] Among these, bisphenol-type cyanate and / or novolac-type cyanate resins are preferred, and a combination of both is even more preferred. The reason for this is that bisphenol-type cyanate ester resins have fewer crosslinking points, so when triazine rings are formed, unreacted cyanate groups are less likely to remain, making it easier to maintain good dielectric properties. Furthermore, novolac-type cyanate resins form triazine rings after the curing reaction, which improves rigidity and heat resistance and makes them easier to accommodate miniaturization and higher frequencies. As the novolac type cyanate resin, for example, one represented by the following formula (I) can be used.

[0053] [ka]

[0054] The average repeating unit number n of the novolac cyanate resin represented by general formula (I) is any integer. The average repeating unit number n is not particularly limited, but is preferably 1 or more, more preferably 2 or more. When the average repeating unit number n is equal to or greater than the above-mentioned lower limit, the heat resistance of the novolac cyanate resin is improved, and elimination and volatilization of oligomers during heating can be suppressed. Furthermore, the average repeating unit number n is not particularly limited, but is preferably 10 or less, more preferably 7 or less. When n is equal to or less than the above-mentioned upper limit, an increase in melt viscosity can be suppressed, and the moldability of the prepreg can be improved.

[0055] The cyanate resin may also be modified, for example, it may contain butadiene-modified cyanate modified with butadiene. Specifically, the butadiene-modified cyanate may be obtained by mixing a cyanate ester compound with polybutadiene and then thermally polymerizing the mixture, and / or by mixing a polymer of a cyanate ester compound with polybutadiene and then thermally polymerizing the mixture. This allows the dielectric properties and moldability to be compatible while maintaining good heat resistance.

[0056] Although there are no particular limitations on the lower limit of the weight-average molecular weight (Mw) of the cyanate resin, Mw is preferably at least 500, and more preferably at least 600. When Mw is at least the above lower limit, the occurrence of tackiness can be suppressed when a prepreg is produced, and the prepregs can be prevented from adhering to each other when they come into contact with each other, or from transferring.

[0057] Furthermore, the upper limit of Mw is not particularly limited, but is preferably not more than 4,500, more preferably not more than 3,000. When Mw is not more than the upper limit, the cyclization reaction of the cyanate resin (C) can be prevented from accelerating, and defects in the insulating layer and a decrease in the peel strength between the insulating layer and the metal layer can be prevented. The Mw of the cyanate resin can be measured, for example, by GPC (gel permeation chromatography, standard substance: polystyrene equivalent).

[0058] Furthermore, one type of cyanate resin may be used alone, or two or more types having different Mw may be used in combination, or one or more types may be used in combination with their prepolymers.

[0059] In this embodiment, the content of the cyanate resin is preferably 0.2 mass % or more, more preferably 0.5 mass % or more, based on the total solid mass of the resin composition for forming a circuit board of this embodiment, which allows for the production of a cured product that is excellent in moldability and high in dielectric constant.

[0060] On the other hand, the content of the cyanate resin is preferably 10% by mass or less, more preferably 5% by mass or less, based on the total solid mass of the resin composition for forming a circuit board of this embodiment, which allows for the production of a cured product that is excellent in moldability and high in dielectric constant.

[0061] (bismaleimide triazine resin) Bismaleimide triazine resin (BT resin) can be obtained from a bismaleimide component and a triazine monomer or prepolymer component having a cyanate group, and contains an imide group and a triazine ring. It may also be modified with epoxy, acrylic esters, divinylbenzene, styrene, triallyl isocyanate, etc. Examples of triazine monomers (cyanate compounds) having a cyanate group include, but are not limited to, 2,2'-di(4-cyanatophenyl)propane, di(4-cyanato-3,5-dimethylphenyl)methane, di(4-cyanatophenyl)thioether, 2,2'-di(4-cyanatophenyl)hexafluoropropane, di(4-cyanatophenyl)ethane, cyanate of phenol-dicyclopentadiene copolymer, and phenol novolac cyanate.

[0062] The bismaleimide triazine resin may be contained in an amount of preferably 1 to 25 mass %, more preferably 3 to 20 mass %, and even more preferably 5 to 15 mass %, based on the total solid mass of the resin composition for forming a circuit board of this embodiment, thereby enabling the production of a cured product that is excellent in moldability and has a high dielectric constant.

[0063] (maleimide resin) The maleimide resin (excluding bismaleimide triazine resin) is preferably a maleimide resin having at least two maleimide groups in the molecule.

[0064] Examples of maleimide resins include resins having two maleimide groups in the molecule, such as 4,4'-diphenylmethane bismaleimide, m-phenylene bismaleimide, p-phenylene bismaleimide, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, bis-(3-ethyl-5-methyl-4-maleimidophenyl)methane, 4-methyl-1,3-phenylene bismaleimide, N,N'-ethylene dimaleimide, N,N'-hexamethylene dimaleimide, bis(4-maleimidophenyl)ether, bis(4-maleimidophenyl)sulfone, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethane bismaleimide, and bisphenol A diphenyl ether bismaleimide; and resins having three or more maleimide groups in the molecule, such as polyphenylmethane maleimide. One of these can be used alone, or two or more can be used in combination. Among these maleimide compounds (A), 4,4'-diphenylmethane bismaleimide, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, bis-(3-ethyl-5-methyl-4-maleimidophenyl)methane, polyphenylmethane maleimide, and bisphenol A diphenyl ether bismaleimide are preferred from the viewpoint of stably obtaining desired dielectric properties. These maleimide resins may be modified with silicone or the like.

[0065] The maleimide resin may be contained in an amount of preferably 1 to 20% by mass, more preferably 2 to 15% by mass, and even more preferably 3 to 10% by mass, based on the total solids mass of the resin composition for forming a circuit board of this embodiment. By setting the content of the maleimide resin to be equal to or greater than the above-mentioned lower limit, a high dielectric constant can be obtained. On the other hand, by setting the content of the maleimide resin to be equal to or less than the above-mentioned upper limit, an increase in viscosity can be suppressed, and good moldability and impregnation properties can be obtained.

[0066] [Thermoplastic resin (C)] The resin composition for forming a circuit board of this embodiment may further contain a thermoplastic resin (C).

[0067] Examples of the thermoplastic resin (C) include phenoxy resin, acrylic resin, methacrylic resin, polyvinyl acetal resin, polyimide resin, polyamide resin, polyamideimide resin, polyphenylene ether resin, polyethersulfone resin, polyester resin, polyethylene resin, polystyrene resin, polysulfone resin, polybutadiene resin, ABS resin, etc. As the thermoplastic resin, one of these may be used alone, or two or more types having different weight average molecular weights may be used in combination, or one or more types may be used in combination with their prepolymers.

[0068] Among these, the thermoplastic resin (C) may include one or more selected from the group consisting of phenoxy resin, polyimide resin, polyamideimide resin, polyamide resin, and polyphenylene ether resin. From the viewpoints of high dielectric constant, moldability, embeddability, and flatness, phenoxy resin and polyimide resin are preferred, and phenoxy resin is more preferred.

[0069] The phenoxy resin is not particularly limited, and examples thereof include phenoxy resins having a bisphenol skeleton such as phenoxy resins having a bisphenol A skeleton, phenoxy resins having a bisphenol F skeleton, phenoxy resins having a bisphenol S skeleton, phenoxy resins having a bisphenol M (4,4'-(1,3-phenylenediisopridiene)bisphenol) skeleton, phenoxy resins having a bisphenol P (4,4'-(1,4)-phenylenediisopridiene)bisphenol) skeleton, and phenoxy resins having a bisphenol Z (4,4'-cyclohexydienebisphenol) skeleton, phenoxy resins having a novolac skeleton, phenoxy resins having an anthracene skeleton, phenoxy resins having a fluorene skeleton, phenoxy resins having a dicyclopentadiene skeleton, phenoxy resins having a norbornene skeleton, phenoxy resins having a naphthalene skeleton, phenoxy resins having a biphenyl skeleton, and phenoxy resins having an adamantane skeleton. The phenoxy resin may have a structure having multiple types of skeletons, or may have different ratios of each skeleton.Furthermore, multiple types of phenoxy resins with different skeletons may be used, or multiple types of phenoxy resins with different weight-average molecular weights may be used, or prepolymers thereof may be used in combination.

[0070] As the phenoxy resin, one having an ester group in the molecule is sometimes preferred. The phenoxy resin having an ester group in the molecule is an esterified phenoxy resin represented by the following general formula (2), which has an epoxy group at the terminal and a weight-average molecular weight Mw of 5,000 or more and 200,000 or less. In this esterified phenoxy resin, some or all of the polar groups, such as hydroxyl groups, which exhibit water absorption, are each capped with a hydrophobic group.

[0071] [ka]

[0072] In the above formula (2), A contains a structure represented by the above formula (3), and R1 and R 2 may be different from each other and are a hydrogen atom or a structure represented by the above formula (4). 1 and R 2 At least one of R is a group represented by the above formula (4). 3 In the formula (3), 5 mol % or more of X are aliphatic carbonyl groups or aromatic carbonyl groups having 1 to 10 carbon atoms, and the remainder are hydrogen atoms, and n is the average number of repeating groups and is an integer of 5 to 500. 1 is a direct bond, a divalent hydrocarbon group having 1 to 13 carbon atoms, a group selected from -O-, -S-, -SO2-, -C(CF3)2- and -CO-, and R 4 ~R 11 are each independently a group arbitrarily selected from a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkenyl group having 1 to 12 carbon atoms, and an alkynyl group having 1 to 12 carbon atoms.

[0073] The structure represented by the above formula (3) is a structure represented by the following formula (5) or (6).

[0074] [ka]

[0075] The lower limit of the weight-average molecular weight (Mw) of the phenoxy resin is, for example, 10,000 or more, preferably 15,000 or more, and more preferably 20,000 or more. This can improve compatibility with other resins and solubility in solvents. On the other hand, the upper limit of the weight-average molecular weight (Mw) of the phenoxy resin is, for example, 60,000 or less, preferably 55,000 or less, and more preferably 50,000 or less. This can improve film-forming properties and moldability.

[0076] The content of the thermoplastic resin (e.g., phenoxy resin) is not particularly limited, but is preferably 0.1 to 20 parts by mass, more preferably 0.2 to 10 parts by mass, and even more preferably 0.5 to 5 parts by mass, relative to the total solid mass of the resin composition for forming a circuit board of this embodiment. When the content is equal to or greater than the lower limit, a decrease in viscosity of the resin composition can be suppressed, resulting in excellent moldability. When the content is equal to or less than the upper limit, a high dielectric constant can be obtained.

[0077] Furthermore, in this embodiment, by setting the content of the phenoxy resin within the above range and setting the average particle size of the high dielectric filler (A) (preferably a phenylaminosilane-treated high dielectric filler) within the above range, the occurrence of voids is suppressed and moldability is improved. Furthermore, when molded under heat and pressure conditions, the resin component and the high dielectric filler flow without separating, thereby suppressing the occurrence of areas where the resin component is present in high concentration, and improving product yield.

[0078] [Other ingredients] The resin composition for forming a circuit board of this embodiment may contain additives other than those described above, such as other resins other than those described above, other inorganic fillers other than the high dielectric filler (A), crosslinking agents, flame retardants, polymerization initiators, coupling agents, curing accelerators, colorants, stress reducers, antifoaming agents, leveling agents, ultraviolet absorbers, foaming agents, antioxidants, ion scavengers, rubber components, etc. These may be used alone or in combination of two or more.

[0079] Examples of resins other than those mentioned above include thermosetting resins such as benzocyclobutene resin.

[0080] [Other inorganic fillers] As other inorganic fillers (hereinafter referred to as inorganic fillers), known inorganic fillers can be used as long as they can achieve the effects of the present invention.

[0081] Examples of inorganic fillers include silicates such as talc, calcined clay, uncalcined clay, mica, and glass; oxides such as titanium oxide, alumina, boehmite, silica, and fused silica; carbonates such as calcium carbonate, magnesium carbonate, and hydrotalcite; hydroxides such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide; sulfates or sulfites such as barium sulfate, calcium sulfate, and calcium sulfite; borates such as zinc borate, barium metaborate, aluminum borate, calcium borate, and sodium borate; nitrides such as aluminum nitride, boron nitride, silicon nitride, and carbon nitride; and titanates such as strontium titanate and barium titanate. Among these, talc, alumina, glass, silica, mica, aluminum hydroxide, and magnesium hydroxide are preferred, and silica is particularly preferred. As the inorganic filler, one of these may be used alone, or two or more may be used in combination.

[0082] The lower limit of the average particle size of the inorganic filler is not particularly limited, but may be, for example, 0.01 μm or more, or 0.05 μm or more. The upper limit of the average particle size of the inorganic filler is not particularly limited, but is, for example, preferably 5.0 μm or less, more preferably 2.0 μm or less, and even more preferably 1.0 μm or less.

[0083] In this embodiment, the average particle diameter of the inorganic filler (C) is determined by measuring the particle size distribution of the particles on a volume basis using, for example, a laser diffraction particle size distribution analyzer (LA-500 manufactured by HORIBA Corporation) and determining the particle diameter at which the cumulative 50% of the particle size distribution is reached (D 50 ) can be used as the average particle size.

[0084] The content of the inorganic filler is preferably 1 to 30 mass % relative to the total solid mass of the resin composition, and more preferably 2 to 20 mass %.

[0085] [Crosslinking agent] The crosslinking agent can be one that has the ability to initiate or accelerate a crosslinking reaction. From the viewpoint of the crosslinking reaction, the crosslinking agent preferably has an average of two or more carbon-carbon unsaturated double bonds or isocyanate groups (-N=C=O) per molecule. The crosslinking agent may be composed of one type of compound or two or more types of compounds.

[0086] Examples of crosslinking agents include trialkenyl isocyanurate compounds such as triallyl isocyanurate (TAIC) and trimethallyl isocyanurate, trialkenyl cyanurate compounds such as triallyl cyanurate (TAC), polyfunctional methacrylate compounds having two or more methacrylic groups in the molecule, polyfunctional acrylate compounds having two or more acrylic groups in the molecule, polyfunctional vinyl compounds having two or more vinyl groups in the molecule such as polybutadiene, vinylbenzyl compounds such as divinylbenzene having a vinylbenzyl group in the molecule, polyfunctional maleimide compounds having two or more maleimide groups in the molecule such as 4,4'-bismaleimide diphenylmethane (excluding the maleimide resins), and isocyanate compounds having one or more isocyanate groups (-N=C=O). These may be used alone or in combination of two or more.

[0087] Among these, the crosslinking agent preferably contains at least one compound selected from the group consisting of triallyl cyanurate, triallyl isocyanurate, polybutadiene, and divinylbenzene, which further increases the crosslink density during the curing reaction (crosslinking reaction) while maintaining good impregnation properties, thereby improving the heat resistance of the cured product of the resin composition. The number average molecular weight of the crosslinking agent is preferably 600 to 4,000, and more preferably 800 to 2,000.

[0088] By setting the number-average molecular weight of the crosslinking agent to the above lower limit or more, the reactivity is increased and a good cured product is obtained. By setting the number-average molecular weight of the crosslinking agent to the above upper limit or less, an increase in the viscosity of the resin composition can be suppressed, resulting in good impregnation properties. In addition, good resin flowability during heat molding can be obtained. The number average molecular weight may be measured by a general molecular weight measurement method, and specifically, a value measured using GPC may be mentioned.

[0089] The content of the crosslinking agent is preferably 1 to 30 mass %, more preferably 2 to 20 mass %, and even more preferably 4 to 18 mass %, relative to the total solid mass of the resin composition of this embodiment.

[0090] [Flame retardant] In this embodiment, examples of the flame retardant include halogen-based flame retardants such as bromine-based flame retardants and phosphorus-based flame retardants. Specific examples of halogen-based flame retardants include bromine-based flame retardants such as pentabromodiphenyl ether, octabromodiphenyl ether, decabromodiphenyl ether, tetrabromobisphenol A, and hexabromocyclododecane, and chlorine-based flame retardants such as chlorinated paraffin. Specific examples of phosphorus-based flame retardants include phosphate esters such as condensed phosphate esters and cyclic phosphate esters, phosphazene compounds such as cyclic phosphazene compounds, phosphinate-based flame retardants such as metal phosphinates such as aluminum dialkylphosphinates, and melamine-based flame retardants such as melamine phosphate and melamine polyphosphate. The flame retardants listed above may be used alone or in combination of two or more. Among these, phosphorus-based flame retardants are preferred.

[0091] The content of the flame retardant is preferably 0.1 to 15 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 1 to 5 parts by mass, per 100 parts by mass of the total solid content of the resin composition.

[0092] [Polymerization initiator] The resin composition for forming a circuit board according to this embodiment may contain a polymerization initiator. This allows component (f) to cure stably regardless of the process conditions. The polymerization initiator is not particularly limited as long as it can accelerate the curing reaction between the modified polyphenylene ether and the thermosetting curing agent. Examples of the polymerization initiator include oxidizing agents such as 1,3-di(t-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexyne, benzoyl peroxide, 3,3',5,5'-tetramethyl-1,4-diphenoquinone, chloranil, 2,4,6-tri-t-butylphenoxyl, t-butylperoxyisopropyl monocarbonate, and azobisisobutyronitrile. These may be used alone or in combination of two or more. Furthermore, to further accelerate the curing reaction, a metal carboxylate or the like may be used in combination.

[0093] Among these, α,α'-bis(t-butylperoxy-m-isopropyl)benzene is preferably used. α,α'-bis(t-butylperoxy-m-isopropyl)benzene has a relatively high reaction initiation temperature, which can suppress the promotion of the curing reaction when curing is not required, such as during prepreg drying, and can suppress a decrease in the storage stability of the resin composition of this embodiment. Furthermore, α,α'-bis(t-butylperoxy-m-isopropyl)benzene has low volatility, so it does not volatilize during prepreg drying or storage, and good stability is obtained.

[0094] [Coupling agent] The resin composition for forming a circuit board of this embodiment may contain a coupling agent. The coupling agent may be added directly during preparation of the resin composition, or may be added to the hollow silica particles (A) in advance. The use of a coupling agent can improve the wettability at the interface between the hollow silica particles (A) and each resin. Therefore, the use of a coupling agent is preferable, and the heat resistance of the cured resin film can be improved. Furthermore, the use of a coupling agent can improve adhesion to copper foil. Furthermore, since moisture absorption resistance can be improved, adhesion to copper foil can be maintained even in a humid environment.

[0095] Examples of the coupling agent include silane coupling agents such as vinyl silane coupling agents, epoxy silane coupling agents, cationic silane coupling agents, and amino silane coupling agents, titanate coupling agents, and silicone oil coupling agents. One type of coupling agent may be used alone, or two or more types may be used in combination. In this embodiment, the coupling agent may contain a silane coupling agent. This can increase the wettability at the interface between the hollow silica particles (A) and each resin, and can further improve the heat resistance of the cured resin film.

[0096] As the silane coupling agent, various types can be used, and examples thereof include epoxy silane, amino silane, alkyl silane, ureido silane, mercapto silane, and vinyl silane.

[0097] Specific compounds include, for example, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, N-phenylγ-aminopropyltriethoxysilane, N-phenylγ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltriethoxysilane, N-6-(aminohexyl)3-aminopropyltrimethoxysilane, N-(3-(trimethoxysilylpropyl)-1,3-benzenedimethanane, γ-glycidoxypropyl Examples include vinyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, methyltrimethoxysilane, γ-ureidopropyltriethoxysilane, vinyltriethoxysilane, etc., and one or more of these can be used in combination. Among these, vinylsilane, epoxysilane, mercaptosilane, and aminosilane are preferred, and as the aminosilane, primary aminosilane or anilinosilane is more preferred.

[0098] (curing accelerator) As the curing accelerator of this embodiment, known accelerators can be used. Examples of the organic compounds include organic metal salts such as zinc naphthenate, cobalt naphthenate, tin octoate, cobalt octoate, zinc octoate, bisacetylacetonate cobalt(II), and trisacetylacetonate cobalt(III); tertiary amines such as triethylamine, tributylamine, and diazabicyclo[2,2,2]octane; imidazoles such as 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 2-phenyl-4-methylimidazole, 2-ethyl-4-ethylimidazole, 2-phenyl-4-ethylimidazole, 2-phenyl-4-methyl-5-hydroxyimidazole, and 2-phenyl-4,5-dihydroxyimidazole; phenolic compounds such as phenol, bisphenol A, and nonylphenol; organic acids such as acetic acid, benzoic acid, salicylic acid, and paratoluenesulfonic acid; and onium salt compounds and derivatives thereof. These may be used alone or in combination of two or more. Among these, imidazole and onium salt compounds are preferred from the viewpoint of stably improving the resin curability. Such onium salt compounds are not particularly limited, but examples thereof include onium salt compounds represented by the following formula (IX):

[0099] [ka]

[0100] In formula (IX), P represents a phosphorus atom, R 1 , R 2 , R 3 and R 4 A each represents an organic group having a substituted or unsubstituted aromatic ring or heterocyclic ring, or a substituted or unsubstituted aliphatic group, and may be the same or different from each other. - represents an anion of a proton donor with a valence of n (n≧1) that has at least one proton in the molecule that can be released outside the molecule, or a complex anion thereof.

[0101] The lower limit of the content of the curing accelerator is not particularly limited, but is preferably 0.005 to 5 mass %, more preferably 0.01 to 2 mass %, of the total resin composition (solid content). By setting the content of the curing accelerator within the above range, a good curing acceleration effect can be obtained.

[0102] <Varnish> In this embodiment, the varnish-like resin composition for forming a circuit board may contain a solvent. Examples of the solvent include organic solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, toluene, ethyl acetate, cyclohexane, heptane, cyclohexane, cyclohexanone, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, ethylene glycol, cellosolve-based solvents, carbitol-based solvents, anisole, and N-methylpyrrolidone. These may be used alone or in combination of two or more.

[0103] When the resin composition for forming a circuit board is in the form of a varnish, the solid content of the resin composition may be, for example, 30% by mass to 80% by mass, more preferably 40% by mass to 70% by mass, which results in a resin composition with excellent workability and film-forming properties.

[0104] The varnish-like resin composition for forming circuit boards can be prepared by dissolving, mixing, and stirring the above-mentioned components in a solvent using various mixers, such as those used in ultrasonic dispersion, high-pressure collision dispersion, high-speed rotation dispersion, bead mill dispersion, high-speed shear dispersion, and rotation-revolution dispersion.

[0105] <Resin composition for circuit board formation> The resin composition for forming a circuit board of this embodiment can have a flow rate measured under the following conditions of preferably 5% or more and 50% or less, more preferably 10% or more and 40% or less, and even more preferably 12% or more and 35% or less. When the flow rate of the resin composition for forming a circuit board of this embodiment is within the above range, the generation of voids, filling properties, and flattening properties are improved, and moldability can be further improved.

[0106] (conditions) The resin composition for forming circuit boards was applied to one side of a 38 μm-thick PET film using a comma coater so that the dried resin layer would be 30 μm thick. This was then dried for 3 minutes in a dryer at 160°C to obtain a resin sheet (resin film with carrier) in which a resin film was laminated on a PET film. The resin sheet was then cut out to prepare test pieces with a diameter of 113 mm. The weight of the PET film was subtracted from the total weight of the four test pieces to calculate the weight of the resin film alone (mass: W0). The four test pieces were stacked together to form a laminate, which was then sandwiched between aluminum foil on both sides and heated and pressurized for 5 minutes at 170°C and 1.5 MPa in a top-bottom press. The resin composition that flowed out of the laminate was removed, and the weight of the PET film was subtracted from the weight of the laminate after testing to calculate the weight of the resin film alone contained in the laminate after testing (mass: W1). The flow rate (%) of the resin composition is calculated using the following formula. Formula: [(W0-W1) / W0]×100

[0107] In order to achieve such a flow rate, it is important to appropriately control the types, amounts, and manufacturing methods of the high dielectric filler (A), thermosetting resin (B), and thermoplastic resin (C).

[0108] <Resin sheet> Next, the resin sheet (resin film) of this embodiment will be described. The resin sheet of this embodiment can be obtained by forming the resin composition in a varnish form into a film. For example, the resin sheet of this embodiment can be obtained by applying the resin composition in a varnish form to a coating film and then removing the solvent from the coating film. In such a resin sheet, the solvent content can be 5 mass % or less based on the entire resin film. In this embodiment, the solvent removal step can be carried out under conditions of, for example, 100°C to 150°C and 1 minute to 5 minutes. This makes it possible to sufficiently remove the solvent while suppressing the progress of curing of the resin film containing a thermosetting resin. The resin sheet of the present embodiment may be composed of a resin film alone, or may be composed so as to contain a fiber base material inside.

[0109] The resin sheet made of the resin composition for forming a circuit board of this embodiment has excellent moldability and excellent ability to fill gaps in circuits, etc. Furthermore, when molded under heat and pressure, the resin component and the high-dielectric filler flow without separating, thereby suppressing the generation of regions where the resin component is present in high concentration, resulting in excellent moldability.

[0110] <Prepreg> The prepreg of this embodiment is obtained by impregnating a fiber substrate with the resin composition. For example, the prepreg can be used as a sheet-like material obtained by impregnating a fiber substrate with the resin composition and then semi-curing the material. A sheet-like material having such a structure has excellent properties such as dielectric properties and mechanical and electrical connection reliability under high temperature and humidity conditions, and is suitable for producing an insulating layer for a printed wiring board, for example.

[0111] In this embodiment, the method for impregnating the resin composition into the fiber substrate is not particularly limited, but examples include a method in which the resin composition is dissolved in a solvent to prepare a resin varnish and the fiber substrate is immersed in the resin varnish, a method in which the resin varnish is applied to the fiber substrate using various coaters, a method in which the resin varnish is sprayed onto the fiber substrate using a sprayer, and a method in which both sides of the fiber substrate are laminated with the resin film made of the resin composition.

[0112] Examples of the fiber substrate include glass fiber substrates such as woven glass cloth and nonwoven glass cloth, inorganic fiber substrates such as woven or nonwoven cloth containing an inorganic compound other than glass as a component, and organic fiber substrates made of organic fibers such as aromatic polyamideimide resin, polyamide resin, aromatic polyester resin, polyester resin, polyimide resin, fluororesin, etc. Among these substrates, the use of a glass fiber substrate typified by woven glass cloth in terms of strength can improve the mechanical strength and heat resistance of the printed wiring board.

[0113] The thickness of the fiber base material is not particularly limited, but is preferably 5 μm to 150 μm, more preferably 10 μm to 100 μm, and even more preferably 12 μm to 90 μm. Use of a fiber base material having such a thickness can further improve the handleability during prepreg production.

[0114] When the thickness of the fiber substrate is equal to or less than the upper limit, the impregnation of the resin composition into the fiber substrate is improved, and the occurrence of strand voids and a decrease in insulation reliability can be suppressed. Furthermore, the formation of through-holes using carbon dioxide, UV, excimer, or other lasers can be facilitated. Furthermore, when the thickness of the fiber substrate is equal to or greater than the lower limit, the strength of the fiber substrate and prepreg can be improved. As a result, handling can be improved, prepreg production can be facilitated, and warping of the resin substrate can be suppressed.

[0115] As the glass fiber substrate, for example, a glass fiber substrate formed of one or more types of glass selected from E glass, S glass, D glass, T glass, NE glass, UT glass, L glass, HP glass, and quartz glass is preferably used.

[0116] In this embodiment, the prepreg can be used to form, for example, an insulating layer in a build-up layer or an insulating layer in a core layer of a printed wiring board. When the prepreg is used to form an insulating layer in a core layer of a printed wiring board, for example, two or more prepregs can be stacked and the resulting laminate can be heat-cured to form an insulating layer for the core layer.

[0117] <Metal-clad laminate> The laminate of this embodiment is a metal-clad laminate in which a metal layer is disposed on at least one surface of the cured product of the prepreg. A method for manufacturing a metal-clad laminate using a prepreg is, for example, as follows.

[0118] Metal foil is placed on both or one of the outer surfaces of a prepreg or a laminate of two or more prepregs, and these are bonded under high vacuum conditions using a laminator or Becquerel apparatus, or metal foil is placed on both or one of the outer surfaces of the prepreg. When two or more prepregs are laminated, metal foil is placed on both or one of the outermost surfaces of the laminated prepregs. The laminate of prepregs and metal foil is then heated and pressurized to obtain a metal-clad laminate. It is preferable to continue pressing during the heating and pressurizing process until cooling is complete.

[0119] Examples of metals constituting the metal foil include copper, copper-based alloys, aluminum, aluminum-based alloys, silver, silver-based alloys, gold, gold-based alloys, zinc, zinc-based alloys, nickel, nickel-based alloys, tin, tin-based alloys, iron, iron-based alloys, Fe-Ni-based alloys such as Kovar (trade name), 42 alloy, Invar, and Super Invar, W, and Mo. Among these, copper or copper alloys are preferred as the metal constituting the metal foil 105 because they have excellent conductivity, are easy to form circuits by etching, and are inexpensive. That is, copper foil is preferred as the metal foil. As the metal foil, a metal foil with a carrier or the like can also be used. The thickness of the metal foil is preferably 0.5 μm or more and 20 μm or less, and more preferably 1.5 μm or more and 18 μm or less.

[0120] <Resin film with carrier> FIG. 1(a) is a cross-sectional view showing an example of the configuration of a resin film 10 with a carrier in this embodiment.

[0121] As shown in Fig. 1(a), the resin film 10 with a carrier of this embodiment can include a carrier substrate 40, a primer layer 30 for a plating process provided on the carrier substrate 40, and an insulating film 20 that serves as a base for the plating layer. In the resin film 10 with a carrier, it is preferable that at least one of the primer layer 30 and the insulating film 20 is made of a resin film made of the above-mentioned resin composition. This can improve the handleability of the resin film.

[0122] 1(b), the resin film 12 with a carrier of this embodiment can include a carrier substrate 40 and a resin film made of the resin composition formed on the carrier substrate 40. The resin film can be used as an insulating film 20 that serves as a base for a plating layer.

[0123] The resin films 10 and 12 with a carrier may be in a roll shape that can be wound up, or in a sheet shape such as a rectangular shape. The surfaces of the resin films 10 and 12 with a carrier may be exposed, or may be covered with a protective film (cover film). As the protective film, a film having a known protective function may be used, and for example, a PET film may be used.

[0124] In this embodiment, the carrier substrate 40 can be, for example, a polymer film or a metal foil. Examples of the polymer film include, but are not limited to, polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate and polybutylene terephthalate; polycarbonate; release paper such as silicone sheets; and heat-resistant thermoplastic resin sheets such as fluorine-based resins and polyimide resins. Examples of the metal foil include, but are not limited to, copper and / or copper-based alloys, aluminum and / or aluminum-based alloys, iron and / or iron-based alloys, silver and / or silver-based alloys, gold and gold-based alloys, zinc and zinc-based alloys, nickel and nickel-based alloys, and tin and tin-based alloys. Among these, a polyethylene terephthalate sheet is most preferred due to its low cost and easy peel strength adjustment. This allows for easy peeling from the carrier-attached resin film 10 with an appropriate strength.

[0125] The lower limit of the thickness of the resin film is not particularly limited, but may be, for example, 1 μm or more, 3 μm or more, or 5 μm or more. This allows the mechanical strength of the resin film 10 to be increased. On the other hand, the upper limit of the thickness of the resin film 10 is not particularly limited, but may be, for example, 500 μm or less, 300 μm or less, or 100 μm or less. This allows the semiconductor device to be made thinner. The thickness of the resin film may be the thickness of the insulating film 20, or the combined thickness of the insulating film 20 and the primer layer 30.

[0126] The lower limit of the thickness of the primer layer 30 is, for example, 1 μm or more, and preferably 2 μm or more. This can improve insulation reliability. On the other hand, the upper limit of the thickness of the primer layer 30 is, for example, 10 μm or less, and preferably 8 μm or less. This can achieve a thinner printed wiring board. Furthermore, by setting the thickness of the primer layer 30 within the above range, a printed wiring board that can accommodate thinner thicknesses can be obtained without losing the properties of the insulating layer in the build-up layer.

[0127] The lower limit of the thickness of the insulating film 20 is, for example, 5 μm or more, and preferably 10 μm or more. This can improve insulation reliability. On the other hand, the upper limit of the thickness of the insulating film 20 is, for example, 50 μm or less, and preferably 40 μm or less. This can achieve a thinner printed wiring board. Furthermore, by setting the thickness of the insulating film 20 within the above range, it is possible to fill the irregularities of the inner layer circuit when manufacturing the printed wiring board, and it is also possible to ensure a suitable thickness of the insulating resin layer of the build-up layer.

[0128] The thickness of the carrier substrate 40 is not particularly limited, but may be, for example, 10 μm or more and 100 μm or less, or 10 μm or more and 70 μm or less, which is preferable because it improves the handleability when producing the carrier-attached resin film 10.

[0129] The resin film of the carrier-attached resin film 10 of this embodiment may be a single layer or a multilayer, and may be composed of one or more types of films. When the resin sheet is multilayered, it may be composed of the same type or different types. Furthermore, the carrier-attached resin film 10 may have a protective film on the outermost layer side of the resin film 10.

[0130] The resin sheet of this embodiment is a resin sheet made of the resin composition for forming a circuit board. The cured film of the resin film is composed of a cured product of the resin composition. The cured film of the cured product of the resin composition can be used as an insulating layer that constitutes a build-up layer of a printed wiring board.

[0131] <Printed wiring board> The printed wiring board of this embodiment is provided with an insulating layer made of the cured product of the above-mentioned resin sheet (cured product of the resin composition).

[0132] In this embodiment, the cured resin sheet can be used, for example, as a buildup layer of a normal printed wiring board, a buildup layer in a printed wiring board having no core layer, a buildup layer in a coreless substrate used in PLP, a buildup layer in an MIS substrate, etc. The insulating layer constituting such a buildup layer can also be suitably used as a buildup layer constituting a large-area printed wiring board used to collectively produce multiple semiconductor packages.

[0133] In the present embodiment, a resin sheet made of a resin composition for forming an insulating film may be impregnated with glass fibers. In a semiconductor package using such a resin film as a build-up layer, the linear expansion coefficient of the cured resin film can be reduced, and package warpage can be sufficiently suppressed.

[0134] (Semiconductor package) FIG. 2 is a cross-sectional view showing an example of the semiconductor package of this embodiment. As shown in FIG. 2(a), the semiconductor device 200 includes an insulating substrate 202 made of a cured product of the resin composition for forming a circuit board of this embodiment, a capacitor 204 built into the insulating substrate 202, and a semiconductor element 210 mounted on the insulating substrate 202 and electrically connected to the capacitor 204.

[0135] The insulating substrate 202 can be prepared using the resin sheet or prepreg made of the resin composition for forming a circuit board of this embodiment. The resin composition for forming a circuit board of this embodiment has excellent moldability and can give a cured product with a high dielectric constant, so it can be suitably used as the insulating substrate 202. A decoupling capacitor can be used as the capacitor 204, and examples of the decoupling capacitor include a thin film capacitor and a multilayer ceramic capacitor. The film thickness of the capacitor 204 is approximately 20 μm to 200 μm. The capacitor 204 and the semiconductor element 210 can be electrically connected via via electrodes 206 and solder 208. The semiconductor element 210 may be an LSI or the like.

[0136] The semiconductor device 200 comprises a semiconductor element 210 and an insulating substrate 202 (interposer) incorporating a capacitor 204. The semiconductor device 200 can be further mounted on a wiring board (not shown), and the semiconductor element 210 can be electrically connected to the wiring of the wiring board via, for example, a through electrode formed in the insulating substrate 202.

[0137] Furthermore, as shown in FIG. 2(b), the semiconductor element 210 can be embedded in the insulating substrate 202. As shown in FIG. 2(b), the semiconductor device 200 includes an insulating substrate 202, a capacitor 204 built into the insulating substrate 202, and a semiconductor element 210 built into the insulating substrate 202 and electrically connected to the capacitor 204. The semiconductor element 210 and the capacitor 204 can be electrically connected by solder bumps 212 . The semiconductor element 210 may be a bare chip or the like.

[0138] The semiconductor device 200 of FIG. 2(b) can be further mounted on a wiring board (not shown), and the semiconductor element 210 can be electrically connected to the wiring of the wiring board via a through electrode formed in the insulating substrate 202, for example.

[0139] Alternatively, the insulating substrate 202 may be a printed wiring board having a circuit layer, and the semiconductor element 210 may be electrically connected to the circuit layer.

[0140] <Wiring board> In this embodiment, the wiring board is a substrate (laminate) with metal foil on one or both sides of which a conductor layer is formed by etching the metal foil into a desired pattern on a dielectric substrate, allowing it to be used as a wiring board on which miniaturized, high-density components are mounted.

[0141] Furthermore, the wiring board of this embodiment can include a microstrip line (feed circuit) and a conductor plate (patch) on the dielectric substrate, the microstrip line including a microstrip line formed by etching the metal foil of a base material (laminate) with metal foil. Furthermore, various pads, vias, and patterns are added to the antenna and device circuit using the wiring board of this embodiment.

[0142] The above etching can be performed by chemical etching (wet etching), and the etching solution can be a copper chloride solution, nitric acid, or the like, or can be performed by a method using other acidic solutions, alkaline solutions, or the like.

[0143] The bonding with the metal foil can be carried out by a known method. For example, the adhesive film and the metal foil can be bonded by continuous processing using a hot roll laminating device having one or more pairs of metal rolls or a double belt press (DBP). Because the device configuration is simple and it is advantageous in terms of maintenance costs, the bonding of the adhesive film and the metal foil is preferably carried out by thermal lamination using a hot roll laminating device having one or more pairs of metal rolls.

[0144] The wiring board of this embodiment may be used in a high frequency band of microwaves, for example, 10 GHz to 100 GHz. In particular, by using a frequency of 60 GHz or higher, moisture absorption can be effectively suppressed, resulting in high reliability.

[0145] <Coreless substrate> 3A to 3C are cross-sectional views showing an example of a manufacturing process for the coreless substrate 300 of this embodiment. First, a sacrificial substrate is prepared. While Fig. 3(a) illustrates a configuration in which the first metal foil 303 is provided in contact with both surfaces of the insulating substrate 301, the sacrificial substrate may be any substrate as long as the first metal foil 303 is provided in contact with at least one surface of the insulating substrate 301. More specifically, the first metal foil 303 is provided on the insulating substrate 301 so that at least a portion of it can be peeled off from the sacrificial substrate in a peeling step described below.

[0146] The first metal foil 303 may be a laminate of multiple metal foils, and in this case, a step of directly bonding the insulating substrate and the first metal foil 303 may be included. More specifically, the step of preparing the sacrificial substrate may include a step of preparing a laminate in which a carrier foil and a metal foil are formed in this order on the insulating substrate 301. In this way, the sacrificial substrate and the first metal foil 303 can be easily separated by peeling the metal foil and the carrier foil.

[0147] A resin substrate is an example of insulating substrate 301. A specific example of the material of the resin substrate is a resin substrate using a prepreg impregnated with the resin composition for circuit boards of this embodiment.

[0148] Specific examples of the material of the first metal foil 303 include one or more selected from the group consisting of copper, nickel, and tin.

[0149] After preparing a sacrificial substrate, a first conductor pattern 305 is formed on a first metal foil 303 of the sacrificial substrate. In this embodiment, the formation of each conductor pattern, such as the first conductor pattern 305, is preferably performed by a modified semi-additive (MSAP) method, from the viewpoint of enabling circuit formation with a narrower pitch. For example, after forming a predetermined resist pattern covering the top of the first metal foil 303, a metal film is selectively grown by an electrolytic plating process such as electrolytic copper plating using the first metal foil 303 as a seed layer to obtain the first conductor pattern 305, and the resist is then removed. Specific examples of the material of the first conductive pattern 305 include one or more selected from the group consisting of copper, nickel, and tin, and copper is preferred.

[0150] After the first conductor pattern 305 is formed, as shown in Fig. 3(b), a first insulating layer 307 is formed on the first conductor pattern 305 so as to cover the first conductor pattern 305. The first insulating layer 307 may be formed, for example, on the entire upper surface of the sacrificial substrate. Here, a second metal foil 309 is provided on the surface of the first insulating layer 307, and the first insulating layer 307 is formed so that the second metal foil 309 is disposed on the outside in the laminated structure. From the viewpoint of improving the strength of first insulating layer 307, a prepreg impregnated with the resin composition for a circuit board of this embodiment can be used as first insulating layer 307.

[0151] After forming the second metal foil 309, a metal film is selectively grown using the second metal foil 309 as a seed layer, for example, by MSAP, to form a second conductor pattern 313, which is a circuit, and via wiring 311 connecting the first conductor pattern 305 and the second conductor pattern 313 ( FIG. 3( c) ). Specifically, vias connecting to the first conductor pattern 305 are formed at predetermined positions in the first insulating layer 307, and after desmearing, a metal plating layer is formed by electroless plating or the like to cover the inner walls of the vias and the upper surface of the second metal foil 309. Thereafter, a resist pattern is selectively formed at predetermined positions on the second metal foil 309, and a metal film constituting the via wiring 311 and the second conductor pattern 313 is grown in the areas where the resist is not formed by electrolytic plating, such as electrolytic copper plating. Thereafter, the resist film is peeled off, and the second metal foil 309 is etched away. The second metal foil 309 may be removed simultaneously with or separately from the first metal foil 303.

[0152] After forming the second conductive pattern 313, a lamination step may be further performed before the peeling step described below. For example, an insulating film covering the second conductive pattern 313 may be formed on the first insulating layer 307. Furthermore, as described below, a third conductive pattern connected to the second conductive pattern 313 may be formed.

[0153] After the second conductive pattern 313 is formed, the insulating substrate 301 is removed. As shown in Fig. 3(d), the insulating substrate 301 is removed from the laminate by peeling the first metal foil 303 from the sacrificial substrate. For example, when the first metal foil 303 is a laminate of a carrier foil and a metal foil, the carrier foil on the insulating substrate 301 is peeled from the metal foil.

[0154] 3(e), the first metal foil 303 remaining under the first insulating layer 307 is removed. From the viewpoint of reducing metal residue, the step of removing the first metal foil 303 preferably includes a step of etching the first metal foil 303, and more preferably a step of flash etching the first metal foil 303. The flash etching can be, for example, etching using an etching solution containing sulfuric acid and hydrogen peroxide. When etching the first metal foil 303, the second metal foil 309 remaining on the first insulating layer 307 may also be etched away. Through the above steps, the coreless substrate 300 is obtained.

[0155] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can be adopted as long as they do not impair the effects of the present invention. [Example]

[0156] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0157] Examples 1 to 7 Preparation of Resin Composition Each component was dissolved or dispersed at the solid content shown in Table 1, adjusted with methyl ethyl ketone to a non-volatile content of 70% by mass, and stirred using a high-speed stirrer to prepare a varnish-like resin composition (resin varnish). The numerical values ​​showing the blending ratio of each component in Table 1 indicate the blending ratio (mass %) of each component relative to the total solid content of the resin composition.

[0158] Details of the raw materials for each component in Table 1 are as follows: Phenylaminosilane-treated barium titanate 1 Phenylaminosilane-treated barium titanate 1 prepared by the following method To 100 parts by mass of barium titanate (Kyoritsu Material Co., Ltd., average particle size 1 μm), 3 parts by mass of N-phenyl-3-aminopropyltrimethoxysilane, a phenylaminosilane compound, was sprayed and mixed for 30 minutes, followed by heat treatment at 60°C for 1 hour while stirring.

[0159] Phenylaminosilane-treated barium titanate 2 Phenylaminosilane-treated barium titanate 2 prepared by the following method 5 parts by mass of N-phenyl-3-aminopropyltrimethoxysilane, a phenylaminosilane compound, was sprayed onto 100 parts by mass of barium titanate (Kyoritsu Material Co., Ltd., average particle size 0.7 μm), and mixed with stirring for 30 minutes. Then, the mixture was heated at 60°C for 1 hour while stirring.

[0160] Phenylaminosilane-treated barium titanate 3 Phenylaminosilane-treated barium titanate 3 prepared by the following method To 100 parts by mass of barium titanate (Kyoritsu Material Co., Ltd., average particle size 0.5 μm), 7 parts by mass of N-phenyl-3-aminooctyltrimethoxysilane, a phenylaminosilane compound, was added, stirred and mixed for 30 minutes, and then heated at 80°C for 1 hour while stirring and mixing.

[0161] Epoxy resin: Biphenyl aralkyl epoxy resin "NC-3000" manufactured by Nippon Kayaku Co., Ltd.

[0162] Benzoxazine resin: Pd-type benzoxazine "P-d" (manufactured by Shikoku Chemical Industry Co., Ltd.) represented by the above formula (4a) Cyanate resin: Phenol novolac cyanate resin "PT-30S" manufactured by Lonza

[0163] Maleimide resin: Biphenylaralkyl maleimide resin "MIR-3000-70MT" manufactured by Nippon Kayaku Co., Ltd.

[0164] Bismaleimide triazine resin (BT resin) A bismaleimide triazine resin was used, which was prepared by dissolving 35 parts by mass of cyanate ester resin "LMP-500S (cyanate equivalent: 200 g / eq)" manufactured by Arcsada, 25 parts by mass of maleimide "BMI-2300" manufactured by Daiwa Chemical Industry Co., Ltd., and 40 parts by mass of dimethylacetamide at 140°C while stirring.

[0165] Phenoxy resin: biphenyl type "YX6954BH30" manufactured by Mitsubishi Chemical Corporation, weight average molecular weight Mw: 20,000

[0166] Leveling agent: Polyacrylate compound "BYK-361N" manufactured by BYK-Chemie Curing accelerator: 2-phenyl-4-methylimidazole "2PZ-PW" manufactured by Shikoku Chemicals Corporation

[0167] (a) Flow rate The resulting resin composition for forming circuit boards was applied to one side of a 38 μm-thick PET film using a comma coater so that the dried resin layer would be 30 μm thick. This was then dried for 3 minutes in a dryer at 160°C to obtain a resin sheet (resin film with carrier) in which a resin film was laminated on a PET film. The resin sheet was then cut out to prepare a test piece with a diameter of 113 mm. The weight of the PET film was subtracted from the total weight of the four test pieces to calculate the weight of the resin film alone (mass: W0). The four test pieces were stacked together to form a laminate, which was sandwiched between aluminum foil on both sides and heated and pressurized for 5 minutes at 170°C and 1.5 MPa using a top-bottom plate press. The resin composition that flowed out of the laminate was removed, and the weight of the PET film was subtracted from the weight of the laminate after testing to calculate the weight of the resin film alone contained in the laminate after testing (mass: W1). The flow rate (%) of the resin composition was calculated using the following formula. Formula: [(W0-W1) / W0]×100

[0168] (b) Electrical properties (dielectric constant Dk / dielectric loss tangent Df) A resin varnish was applied to one side of a 38 μm thick PET film using a comma coater so that the total thickness of the resin layer after drying would be 30 μm, and this was dried for 3 minutes in a drying device at 160°C to obtain a resin sheet (resin film with carrier) in which a resin film was laminated on the PET film. Next, four 30 μm thick resin films with a carrier were stacked on top of each other, and hot pressed with copper foil at 200°C and 0.5 kgf / mm 2 The resin film was cured by heating and pressing for 2 hours under the pressing conditions of 1.0 to 1.5 for 2 hours to obtain a laminate of the cured film and the copper foil. The copper foil of the obtained laminate was then removed by etching to obtain a cured film. The dielectric constant Dk / dielectric loss tangent Df of the cured film at 10 GHz was measured using a cavity resonator method.

[0169] (c) Coefficient of linear expansion (CTE) The thermal expansion coefficient was measured using a TMA (thermal mechanical analysis) device (TA Instruments, Q400) by preparing a 4 mm x 20 mm test piece and measuring the linear expansion coefficient (CTE) α1 during the second cycle of heating from 50 to 150°C under the conditions of a temperature range of 30 to 300°C, 10°C / min, and a load of 5 g. The sample used was the cured film prepared for the evaluation of electrical properties (b).

[0170] (d) Storage modulus The storage modulus (GPa) was calculated at 30°C using a dynamic viscoelasticity device in accordance with JISC-6481 (DMA method). The sample used was the cured film prepared for the evaluation of electrical properties (b).

[0171] (e) Peel strength The peel strength was measured in accordance with JISC-6481. The sample used was the laminate prepared for the evaluation of electrical properties (b).

[0172] (f) Formability The cured film prepared for the evaluation of electrical properties (b) was placed on a circuit board with a circuit height of 18 μm and a copper residual ratio of 60%, and then heated and pressurized at 225°C for 2 hours under a pressure of 3 MPa and a heating rate of 4°C / min. Moldability was evaluated according to the following criteria. (Evaluation criteria) A: Uniform and filler-free area (area where resin components are present in high concentration) is less than 5 mm B: Partially uneven, with filler-free areas of 5mm to less than 10mm C: Uneven, with filler-free areas of 10 mm or more The upper rows of each of Examples 1 to 4 in Figure 4 show photographs of the surface of the sample after the test. The left image in the upper row is a partially enlarged photograph. The lower rows of each of Examples 1 to 4 in Figure 4 show photographs of the cross section of the sample after the test, taken with a scanning electron microscope. In the figures, the circled black areas indicate areas where the resin component is present at a high concentration.

[0173] [Table 1] [Explanation of symbols]

[0174] 10 Resin film with carrier 12 Resin film with carrier 20 insulating film 30 primer layer 40 Carrier substrate 100 Core Layer 102 Insulating layer 104 Beer Hall 106 Electroless metal plating film 108 Metal layer 200 Semiconductor device 202 Insulating substrate 204 Capacitor 206 Via electrode 208 Solder 210 Semiconductor elements 300 Coreless Substrate 301 Insulating substrate 303 First Metal Foil 305 First Conductor Pattern 307 First insulating layer 309 Second Metal Foil 310 Coreless substrate 311 Via wiring 313 Second Conductor Pattern

Claims

1. (A) a high dielectric filler; (B) a thermosetting resin; A resin composition for forming a circuit board, comprising: (A) the high dielectric filler is one or more selected from the group consisting of barium titanate, calcium titanate, strontium titanate, magnesium titanate, bismuth titanate, zirconium titanate, zinc titanate, magnesium zirconate, strontium zirconate, barium zirconate, calcium titanate zirconate, lead titanate zirconate, barium magnesium niobate, and calcium zirconate; (B) A resin composition for forming a circuit board, wherein the thermosetting resin is one or more selected from the group consisting of an epoxy resin, a benzoxazine resin, a cyanate resin, a bismaleimide triazine resin, a maleimide resin, a phenolic resin, a polyimide resin, and a melamine resin.

2. 2. The resin composition for forming a circuit board according to claim 1, wherein the highly dielectric filler (A) has an amino-based silane group on its surface.

3. 3. The resin composition for forming a circuit board according to claim 2, wherein the high dielectric filler (A) is a phenylaminosilane-treated high dielectric filler.

4. 4. The resin composition for forming a circuit board according to claim 3, wherein the phenylaminosilane-treated high dielectric filler comprises one or more selected from the group consisting of barium titanate, calcium titanate, and strontium titanate, all of which have been treated with phenylaminosilane.

5. 4. The resin composition for forming a circuit board according to claim 3, wherein the average particle size of the phenylaminosilane-treated high dielectric filler is 0.1 μm or more and 3 μm or less.

6. 4. The resin composition for forming a circuit board according to claim 3, wherein the phenylaminosilane-treated high dielectric filler comprises two or more types of phenylaminosilane-treated high dielectric fillers having different average particle sizes.

7. The resin composition for forming a circuit board according to claim 1 , wherein the thermosetting resin (B) comprises a benzoxazine resin.

8. The resin composition for forming a circuit board according to claim 1 , further comprising a phenoxy resin.

9. The resin composition for forming a circuit board according to claim 1, The resin composition for forming a circuit board contains the phenoxy resin in an amount of 0.1 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the resin composition for forming a circuit board.

10. 2. The resin composition for forming a circuit board according to claim 1, wherein the flow rate measured under the following conditions is 5% or more and 50% or less. (conditions) The resin composition for forming a circuit board was applied to one side of a 38 μm-thick PET film using a comma coater so that the thickness of the resin layer after drying was 30 μm. This was then dried for 3 minutes in a drying device at 160°C to obtain a resin sheet (resin film with carrier) in which a resin film was laminated on the PET film. Next, the resin sheet was cut out to prepare a test piece with a diameter of 113 mm. The weight of the PET film was subtracted from the total weight of the four test pieces obtained to calculate the weight of the resin film alone (mass: W0). The four test pieces were stacked to form a laminate, which was then sandwiched between aluminum foils and heated and pressed for 5 minutes using a top and bottom flat press at 170°C and 1.5 MPa. The resin composition that flowed out of the laminate was removed, and the weight of the PET film was subtracted from the weight of the laminate after the test to calculate the weight of only the resin film contained in the laminate after the test (mass: W1). The flow rate (%) of the resin composition is calculated using the following formula. Formula: [(W0-W1) / W0]×100

11. A resin sheet comprising the resin composition for forming a circuit board according to any one of claims 1 to 10.

12. A carrier substrate; A resin film with a carrier, comprising: a resin sheet formed on the carrier substrate and comprising the resin composition for forming a circuit board according to any one of claims 1 to 10.

13. A prepreg obtained by impregnating a fiber base material with the resin composition for forming a circuit board according to any one of claims 1 to 10.

14. A laminate comprising the prepreg according to claim 13 and a metal layer disposed on at least one surface of the prepreg.

15. A printed wiring board comprising an insulating layer formed from a cured product of the resin composition for forming a circuit board according to any one of claims 1 to 10.

16. An insulating substrate formed from a cured product of the resin composition for forming a circuit board according to any one of claims 1 to 10; a capacitor embedded in the insulating substrate; a semiconductor element mounted on the insulating substrate or embedded in the insulating substrate and electrically connected to the capacitor; A semiconductor device comprising:

17. A coreless substrate comprising a build-up layer including an insulating layer formed of a cured product of the resin composition for forming a circuit board according to any one of claims 1 to 10, and a circuit layer.

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