Method for manufacturing circuit board

Abstract

To provide a method for manufacturing a circuit board that includes a cured material layer having a polished surface where formation of a recessed part is suppressed.SOLUTION: A method for manufacturing a circuit board includes in the following order the steps of: forming a first resin composition layer by a first resin composition containing an inorganic filler and a curable resin; curing the first resin composition layer to form a first cured layer; polishing a surface of the first cured layer; forming a second resin composition layer on a surface of the polished first cured layer, by a second resin composition containing a curable resin; curing the second resin composition layer to form a second cured layer; and polishing a surface, of the second cured layer, on a side opposite the first cured layer. If the second resin composition contains an inorganic filler, the 99% particle size of the inorganic filler is 2 μm or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a circuit board.

Background Art

[0002] Circuit boards such as printed wiring boards and semiconductor chip packages may include a cured product layer formed by curing a resin composition. These cured product layers usually have insulating properties and can be used as a sealing layer or an insulating layer. For example, in a semiconductor chip package, a sealing layer for sealing a semiconductor chip may be formed by a cured product layer. Also, a redistribution formation layer as an insulating layer for insulating between redistribution layers connected to a semiconductor chip may be formed by a cured product layer. The resin composition for forming such a cured product layer may contain an inorganic filler (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a cured product layer containing an inorganic filler, a polished surface may be formed by polishing. Polishing is generally performed to form the polished surface as a highly smooth plane. In this specification, the term "polishing" may include grinding unless otherwise specified. A thin film layer may be formed on the formed polished surface by a photosensitive resin composition, or a conductor layer may be formed by a conductor material.

[0005] However, when the cured product layer containing the inorganic filler is polished to form a polished surface, unintended recesses may be formed on the polished surface. On the polished surface where the recesses are formed, stable layer formation cannot be performed, and defects may occur in the layer. For example, when forming a thin film layer using a photosensitive resin composition on the polished surface, the thin film layer cannot be formed on the recesses, and defects may be formed. When the thin film layer is an insulating layer that insulates between wirings or when forming wirings using the thin film layer as a photoresist, unintended conduction may occur at the defective portion, which may cause insulation failure.

[0006] The present invention was devised in view of the above problems, and an object thereof is to provide a method for manufacturing a circuit board including a cured product layer having a polished surface with suppressed formation of recesses.

Means for Solving the Problems

[0007] The present inventor diligently studied to solve the above problems. As a result, the present inventor found that by further performing formation, curing, and polishing of the resin composition layer on the polished surface, formation of recesses can be suppressed, and completed the present invention. That is, the present invention includes the following.

[0008] <1> A step of forming a first resin composition layer with a first resin composition containing an inorganic filler and a curable resin, A step of curing the first resin composition layer to form a first cured layer, A step of polishing the surface of the first cured layer, A step of forming a second resin composition layer on the polished surface of the first cured layer with a second resin composition containing a curable resin, A step of curing the second resin composition layer to form a second cured layer, and, A step of polishing the surface of the second cured layer on the side opposite to the first cured layer, in this order; The second resin composition does not contain an inorganic filler or contains it; A method for manufacturing a circuit board, wherein when the second resin composition contains an inorganic filler, 99% of the particle size of the inorganic filler is 2 μm or less. <2> The method for manufacturing a circuit board according to <1>, wherein 99% of the particle size of the inorganic filler contained in the first resin composition is larger than 2 μm. <3> The method for manufacturing a circuit board according to <1> or <2>, wherein the average particle size of the inorganic filler contained in the second resin composition is smaller than the average particle size of the inorganic filler contained in the first resin composition. <4> The method for manufacturing a circuit board according to any one of <1> to <3>, wherein the Vickers hardness of the surface of the polished second cured layer is 10 HV or more. <5> The method for manufacturing a circuit board according to any one of <1> to <4>, wherein the elastic modulus G1 of the first cured layer is 10 GPa or more. <6> The method for manufacturing a circuit board according to any one of <1> to <5>, wherein the ratio G1 / G2 of the elastic modulus G1 of the first cured layer to the elastic modulus G2 of the second cured layer is 1.1 or more. <7> The method for manufacturing a circuit board according to any one of <1> to <6>, including a step of forming a conductor layer on the surface of the polished second cured layer. <8> The method for manufacturing a circuit board according to any one of <1> to <7>, wherein the circuit board is a semiconductor chip package. <9> The method for manufacturing a circuit board according to any one of <1> to <8>, wherein a sealing layer or a redistribution formation layer is formed by the first cured layer and the second cured layer.

Advantages of the Invention

[0009] According to the present invention, it is possible to provide a method for manufacturing a circuit board including a cured product layer having a polished surface with suppressed formation of recesses.

Brief Description of the Drawings

[0010]

Figure 1

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Figure 6

Figure 7

[0011] Hereinafter, embodiments and exemplifications of the present invention will be described in detail. However, the present invention is not limited to the following embodiments and exemplifications, and can be arbitrarily modified and implemented without departing from the scope of the claims and their equivalents.

[0012] In the following description, the term “(meth)acrylic acid” includes acrylic acid, methacrylic acid, and combinations thereof. The term “(meth)acrylate” includes acrylate, methacrylate, and combinations thereof.

[0013] <Overview of the Method for Manufacturing a Circuit Board> A method of manufacturing a circuit board according to an embodiment of the present invention includes: Step (I) of forming a first resin composition layer with a first resin composition containing an inorganic filler and a curable resin; Step (II) of curing the first resin composition layer to form a first cured layer; Step (III) of polishing the surface of the first cured layer; Step (IV) of forming a second resin composition layer on the polished surface of the first cured layer with a second resin composition containing a curable resin; Step (V) of curing the second resin composition layer to form a second cured layer; and Step (VI) of polishing the surface of the second cured layer opposite to the first cured layer is included in this order. Further, the second resin composition either does not contain an inorganic filler or contains an inorganic filler. When the second resin composition contains an inorganic filler, 99% of the particle size of the inorganic filler in the second resin composition is in a small range equal to or less than a specific value. Here, the 99% particle size of the inorganic filler represents the particle size at which the cumulative volume from the small-diameter side in the volume-based particle size distribution of the inorganic filler becomes 99%.

[0014] According to the method for manufacturing a circuit board according to this embodiment, a circuit board including a cured product layer having a polished surface with suppressed formation of recesses can be manufactured. Hereinafter, the mechanism by which this effect is obtained will be described by taking the case of forming a cured product layer on a substrate as an example.

[0015] FIGS. 1 to 6 are cross-sectional views schematically showing a method for manufacturing a circuit board according to an embodiment of the present invention. A method for manufacturing a circuit board according to an example includes, as shown in FIG. 1, a step (I) of forming a first resin composition layer 210 on a surface 100U of a suitable substrate 100 with a first resin composition 30 containing an inorganic filler 10 and a curable resin 20; a step (II) of curing the first resin composition layer 210 to form a first cured layer 200, as shown in FIG. 2; and a step (III) of polishing the surface 200U of the first cured layer 200, as shown in FIG. 3, in this order. By polishing, the thickness of the first cured layer 200 becomes smaller, and a polished surface is formed as the surface 200U of the first cured layer 200.

[0016] When viewed macroscopically, the surface 200U as the polished surface is a smooth plane. However, when viewed microscopically, recesses 220 and 230 may be formed on the surface 200U. Some of the recesses 220 may be formed by some of the particles 11 of the inorganic filler 10 detaching from the first cured layer 200 due to the frictional force during polishing. Also, generally, some of the particles 12 of the inorganic filler 10 may have voids 13 formed inside. When the particles 12 of the inorganic filler 10 having the voids 13 are polished and the voids 13 open due to the particles 12 being shaved, the recesses 230 may be formed by the voids 13. Conventionally, the recesses 220 and 230 may have been formed due to the inorganic filler 10 in this way.

[0017] Therefore, the method for manufacturing a circuit board according to the present embodiment further includes, as shown in FIG. 4, a step (IV) of forming a second resin composition layer 310 on the surface 200U of the polished first cured layer 200 with a second resin composition 50 containing a curable resin 40; a step of curing the second resin composition layer 310 as shown in FIG. 5 to form a second cured layer 300; and a step (VI) of polishing the surface 300U of the second cured layer 300 on the side opposite to the first cured layer 200 as shown in FIG. 6, in this order.

[0018] By forming the second cured layer 300 using the second resin composition 50 on the surface 200U of the first cured layer 200, a cured product layer 400 including the first cured layer 200 and the second cured layer 300 is obtained on the base material 100. Since the recesses 220 and 230 on the surface 200U of the first cured layer 200 are filled by the second cured layer 300, they do not appear on the surface 300U of the second cured layer 300. Also, since the second cured layer 300 does not contain an inorganic filler or has few particles of the inorganic filler with a large particle size in the second cured layer 300, and further the surface 300U of the second cured layer 300 is polished, the surface 300U can form a smooth polished surface of the cured product layer 400. Therefore, by the above manufacturing method, a circuit board 500 including a cured product layer 400 having a polished surface 300U with the formation of recesses suppressed can be manufactured.

[0019] <Step (I) of forming the first resin composition layer> The method for manufacturing a circuit board according to an embodiment of the present invention includes a step (I) of forming a first resin composition layer with a first resin composition containing an inorganic filler and a curable resin. Hereinafter, the inorganic filler contained in the first resin composition may be referred to as "(A) first inorganic filler". Further, the curable resin contained in the first resin composition may be referred to as "(B) first curable resin". According to step (I), a first resin composition layer containing the first resin composition is formed. Usually, this first resin composition layer contains only the first resin composition.

[0020] (Explanation of (A) first inorganic filler) The (A) first inorganic filler as the component (A) contained in the first resin composition is usually contained in the first resin composition in a particulate state and can be contained in the first cured layer while maintaining the particulate state.

[0021] (A) As the material of the first inorganic filler, an inorganic compound is used. Examples of the material of the (A) first inorganic filler include silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, silica and alumina are preferable, and silica is particularly preferable. Therefore, the (A) first inorganic filler preferably contains silica and may contain only silica. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. Further, spherical silica is preferable as the silica. The (A) first inorganic filler may be used alone or in combination of two or more.

[0022] (A) Examples of commercially available products of the first inorganic filler include, for example, "SP60-05" and "SP507-05" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YC100C", "YA050C", "YA050C-MJE", "YA010C", "SC2500SQ", "SO-C4", "SO-C2", "SO-C1" manufactured by Admatechs Co., Ltd.; "UFP-30", "DAW-03", "FB-105FD" manufactured by Denka Co., Ltd.; "Silfill NSS-3N", "Silfill NSS-4N", "Silfill NSS-5N" manufactured by Tokuyama Corporation; "Cellspheres", "MGH-005" manufactured by Taiheiyo Cement Corporation; "Esferique", "BA-1" manufactured by JGC Catalysts & Chemicals Ltd., and the like.

[0023] (A) The 99% particle size of the first inorganic filler is preferably greater than 2 μm, more preferably 3 μm or more, still more preferably 4 μm or more, and preferably 50 μm or less, more preferably 20 μm or less, still more preferably 10 μm or less. (A) As described above, the 99% particle size of the inorganic filler such as the first inorganic filler represents the particle size at which the cumulative volume from the smaller diameter side in the volume-based particle size distribution of the inorganic filler becomes 99%. When (A) the first inorganic filler has a 99% particle size within such a range, the embeddability when embedding the conductor layer and the component in the first resin composition layer can be improved. Further, when the 99% particle size of (A) the first inorganic filler is large in this way, concave portions were conventionally likely to be formed on the polished surface, but according to the method for manufacturing a circuit board according to the present embodiment, it is possible to suppress the formation of such concave portions on the polished surface of the cured product layer.

[0024] (A) The average particle size D1 of the first inorganic filler is preferably 0.1 μm or more, more preferably 0.5 μm or more, still more preferably 1 μm or more, and preferably 20 μm or less, more preferably 10 μm or less, still more preferably 5 μm or less.

[0025] (A) The 99% particle size and the average particle size of the inorganic filler such as the first inorganic filler can be measured by the laser diffraction / scattering method based on the Mie scattering theory. Specifically, a particle size distribution of the inorganic filler is created on a volume basis by a laser diffraction / scattering type particle size distribution measuring device. In this particle size distribution, the particle size at which the cumulative volume calculated from the smaller particle size side becomes 99% can be calculated as the 99% particle size. Also, the median diameter of the said particle size distribution can be calculated as the average particle size. As the measurement sample, 100 mg of the inorganic filler and 10 g of methyl ethyl ketone can be weighed into a vial and dispersed by ultrasonic waves for 10 minutes. The measurement sample is measured for the volume-based particle size distribution of the inorganic filler by a flow cell method using a laser diffraction type particle size distribution measuring device with the wavelengths of the light sources used being blue and red. Examples of the laser diffraction type particle size distribution measuring device include "LA-960" manufactured by Horiba, Ltd.

[0026] (A) The specific surface area of the first inorganic filler is preferably 0.1 m 2 / g or more, more preferably 0.5 m 2 / g or more, still more preferably 1 m 2 / g or more, particularly preferably 3 m 2 / g or more, and preferably 100 m 2 / g or less, more preferably 70 m 2 / g or less, still more preferably 50 m 2 / g or less, particularly preferably 40 m 2 / g or less. (A) The specific surface area of the inorganic filler such as the first inorganic filler can be measured by adsorbing nitrogen gas on the sample surface using a specific surface area measuring device (Macsorb HM-1210 manufactured by Mountech Co., Ltd.) in accordance with the BET method and calculating the specific surface area using the BET multi-point method.

[0027] (A) The first inorganic filler is preferably treated with a surface treatment agent from the viewpoints of enhancing moisture resistance and dispersibility. Examples of the surface treatment agent include fluorine-containing silane coupling agents, aminosilane-based coupling agents, epoxysilane-based coupling agents, mercaptosilane-based coupling agents, silane-based coupling agents, alkoxysilanes, organosilazane compounds, titanate-based coupling agents, and the like. The surface treatment agent may be used alone or in any combination of two or more kinds.

[0028] Examples of commercially available surface treatment agents include "KBM403" (3-glycidoxypropyltrimethoxysilane), "KBM803" (3-mercaptopropyltrimethoxysilane), "KBE903" (3-aminopropyltriethoxysilane), "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), "SZ-31" (hexamethyldisilazane), "KBM103" (phenyltrimethoxysilane), "KBM-4803" (long-chain epoxy type silane coupling agent), "KBM-7103" (3,3,3-trifluoropropyltrimethoxysilane), etc., all manufactured by Shin-Etsu Chemical Co., Ltd.

[0029] The degree of surface treatment with the surface treatment agent preferably falls within a specific range from the viewpoint of improving the dispersibility of the (A) first inorganic filler. Specifically, 100% by mass of the (A) first inorganic filler is preferably surface-treated with 0.2% to 5% by mass of the surface treatment agent, more preferably surface-treated with 0.2% to 3% by mass of the surface treatment agent, and even more preferably surface-treated with 0.3% to 2% by mass of the surface treatment agent.

[0030] The degree of surface treatment with the surface treatment agent can be evaluated by the amount of carbon per unit surface area of the (A) first inorganic filler. The amount of carbon per unit surface area of the (A) first inorganic filler is 0.02 mg / m from the viewpoint of improving the dispersibility of the (A) first inorganic filler. 2The above is preferable, 0.1 mg / m 2 The above is more preferable, 0.2 mg / m 2 The above is even more preferable. On the other hand, from the viewpoint of suppressing the increase in the melt viscosity of the first resin composition, 1.0 mg / m 2 The following is preferable, 0.8 mg / m 2 The following is more preferable, 0.5 mg / m 2 The following is even more preferable.

[0031] (A) The amount of carbon per unit surface area of the inorganic filler such as the first inorganic filler can be measured after washing the surface-treated inorganic filler with a solvent (for example, methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent is added to the inorganic filler surface-treated with a surface treatment agent, and ultrasonic cleaning is performed at 25 °C for 5 minutes. After removing the supernatant and drying the solid content, the amount of carbon per unit surface area of the inorganic filler can be measured using a carbon analyzer. As the carbon analyzer, "EMIA-320V" manufactured by Horiba, Ltd. etc. can be used.

[0032] The range of the amount of (A) the first inorganic filler in the first resin composition is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, particularly preferably 80% by mass or more, and preferably 95% by mass or less, more preferably 90% by mass or less, still more preferably 85% by mass or less, based on 100% by mass of the non-volatile components in the first resin composition. The non-volatile components in the first resin composition refer to the components contained in the first resin composition excluding (H) the solvent, unless otherwise specified. When the amount of (A) the first inorganic filler is within the above range, the elastic modulus, dielectric tangent, and linear thermal expansion coefficient of the first cured layer can be effectively improved. Further, when such a large amount of (A) the first inorganic filler is used, conventionally, unintended recesses tend to be formed on the polished surface of the first cured layer. However, according to the manufacturing method according to the present embodiment, such recesses can be filled with the second cured layer, and a cured product layer having a polished surface with the formation of recesses suppressed can be obtained.

[0033] ((B) Explanation of the first curable resin) The (B) first curable resin as the component (B) contained in the first resin composition is a curable resin, which may be a thermosetting resin, a photocurable resin, or a combination thereof. Further, the (B) first curable resin may be used alone or in combination of two or more. Among them, the (B) first curable resin preferably contains a thermosetting resin. The (B) first curable resin may contain only a thermosetting resin.

[0034] Examples of the thermosetting resin include epoxy resin, active ester resin, phenolic resin, carbodiimide resin, acid anhydride resin, benzoxazine resin, cyanate ester resin, amine resin, thiol resin, and radical polymerizable resin.

[0035] The (B) first curable resin preferably contains an epoxy resin. In particular, it is more preferable that the (B) first curable resin contains a combination of an epoxy resin and a resin that can react and bond with the epoxy resin to cure the (B) first curable resin. A resin that can react and bond with the epoxy resin may be hereinafter referred to as a "curing agent".

[0036] Epoxy resin represents a curable resin having an epoxy group. Examples of epoxy resins include novolac epoxy resins, bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, bisphenol AF epoxy resins, dicyclopentadiene epoxy resins, tris-phenol epoxy resins, naphthol novolac epoxy resins, phenol novolac epoxy resins, tert-butyl-catechol epoxy resins, naphthalene epoxy resins, naphthol epoxy resins, anthracene epoxy resins, glycidylamine epoxy resins, glycidyl ester epoxy resins, cresol novolac epoxy resins, phenol aralkyl epoxy resins, biphenyl epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexane epoxy resins, cyclohexanedimethanol epoxy resins, naphthylene ether epoxy resins, trimethylol epoxy resins, tetraphenylethane epoxy resins, isocyanurate epoxy resins, phenolphthalimide epoxy resins, and the like. The epoxy resin may be used alone or in combination of two or more kinds.

[0037] From the perspective of obtaining a cured product with excellent heat resistance, the epoxy resin preferably contains an epoxy resin containing an aromatic structure. The aromatic structure is a chemical structure generally defined as aromatic, and includes polycyclic aromatics and aromatic heterocycles. Examples of the epoxy resin containing an aromatic structure include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol novolak type epoxy resin, phenol novolak type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, biscylenol type epoxy resin, glycidylamine type epoxy resin having an aromatic structure, glycidyl ester type epoxy resin having an aromatic structure, cresol novolak type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin having an aromatic structure, epoxy resin having a butadiene structure with an aromatic structure, alicyclic epoxy resin having an aromatic structure, heterocyclic epoxy resin, spiro ring-containing epoxy resin having an aromatic structure, cyclohexanedimethanol type epoxy resin having an aromatic structure, naphthylene ether type epoxy resin, trimethylol type epoxy resin having an aromatic structure, tetraphenylethane type epoxy resin having an aromatic structure, and the like.

[0038] (B) The first curable resin preferably contains an epoxy resin having two or more epoxy groups in one molecule. The ratio of the epoxy resin having two or more epoxy groups in one molecule is preferably 50% by mass or more, more preferably 60% by mass or more, and still more preferably 70% by mass or more with respect to 100% by mass of the non-volatile components of the entire epoxy resin.

[0039] Epoxy resins include liquid epoxy resins (hereinafter sometimes referred to as "liquid epoxy resins") that are liquid at a temperature of 20°C and solid epoxy resins (hereinafter sometimes referred to as "solid epoxy resins") that are solid at a temperature of 20°C. (B) The first curable resin may contain only liquid epoxy resin, only solid epoxy resin, or a combination of liquid epoxy resin and solid epoxy resin.

[0040] As the liquid epoxy resin, a liquid epoxy resin having two or more epoxy groups in one molecule is preferred.

[0041] As the liquid epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, phenol novolac type epoxy resin, alicyclic epoxy resin having an ester skeleton, cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, and epoxy resin having a butadiene structure are preferred.

[0042] Specific examples of the liquid epoxy resin include "HP-4032", "HP-4032-D", "HP-4032-SS" (naphthalene-type epoxy resin) manufactured by DIC Corporation; "828US", "828EL", "jER828EL", "825", "Epicoat 828EL" (bisphenol A-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER807", "1750" (bisphenol F-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER152" (phenol novolak-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "630", "630LSD", "604" (glycidylamine-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "ED-523T" (glycerol-type epoxy resin) manufactured by ADEKA Corporation; "EP-3950L", "EP-3980S" (glycidylamine-type epoxy resin) manufactured by ADEKA Corporation; "EP-4088S" (dicyclopentadiene-type epoxy resin) manufactured by ADEKA Corporation; "ZX1059" (a mixture of bisphenol A-type epoxy resin and bisphenol F-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "EX-721" (glycidyl ester-type epoxy resin) manufactured by Nagase ChemteX Corporation; "Celoxide 2021P" (alicyclic epoxy resin having an ester skeleton) manufactured by Daicel Corporation; "PB-3600", "JP-100", "JP-200" (epoxy resin having a butadiene structure) manufactured by Nippon Soda Co., Ltd.; "ZX1658", "ZX1658GS" (liquid 1,4-glycidylcyclohexane-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd. These may be used alone or in combination of two or more.

[0043] As the solid epoxy resin, a solid epoxy resin having three or more epoxy groups in one molecule is preferred, and an aromatic solid epoxy resin having three or more epoxy groups in one molecule is more preferred.

[0044] As the solid epoxy resin, a vicxylenol type epoxy resin, a naphthalene type epoxy resin, a naphthalene type tetrafunctional epoxy resin, a naphthol novolak type epoxy resin, a cresol novolak type epoxy resin, a dicyclopentadiene type epoxy resin, a trisphenol type epoxy resin, a naphthol type epoxy resin, a biphenyl type epoxy resin, a naphthylene ether type epoxy resin, an anthracene type epoxy resin, a bisphenol A type epoxy resin, a bisphenol AF type epoxy resin, a phenol aralkyl type epoxy resin, a tetraphenylethane type epoxy resin, a phenolphthalimide type epoxy resin are preferable.

[0045] Specific examples of the solid epoxy resin include "HP4032H" (naphthalene-type epoxy resin) manufactured by DIC Corporation; "HP-4700" and "HP-4710" (naphthalene-type tetrafunctional epoxy resin) manufactured by DIC Corporation; "N-690" (cresol novolak-type epoxy resin) manufactured by DIC Corporation; "N-695" (cresol novolak-type epoxy resin) manufactured by DIC Corporation; "HP-7200", "HP-7200HH", "HP-7200H", "HP-7200L" (dicyclopentadiene-type epoxy resin) manufactured by DIC Corporation; "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000", "HP6000L" (naphthylene ether-type epoxy resin) manufactured by DIC Corporation; "EPPN-502H" (trisphenol-type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC7000L" (naphthol novolak-type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC3000H", "NC3000", "NC3000L", "NC3000FH", "NC3100" (biphenyl-type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "ESN475V" and "ESN4100V" (naphthalene-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ESN485" (naphthol-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ESN375" (dihydroxynaphthalene-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YX4000H", "YX4000", "YX4000HK", "YL7890" (bixylenol-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YL6121" (biphenyl-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX8800" (anthracene-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX7700" (phenol aralkyl-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "PG-100" and "CG-500" manufactured by Osaka Gas Chemical Co., Ltd.; "YX7760" (bisphenol AF-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YL7800" (fluorene-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER1010" (bisphenol A-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER1031S" (tetraphenylethane-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "WHR991S" (phenolphthalimide-type epoxy resin) manufactured by Nippon Kayaku Co., Ltd., and the like.These may be used alone or in combination of two or more kinds.

[0046] When using a combination of a liquid epoxy resin and a solid epoxy resin as the epoxy resin, their mass ratio (liquid epoxy resin: solid epoxy resin) is preferably 20:1 to 1:20, more preferably 10:1 to 1:10, and particularly preferably 7:1 to 1:7.

[0047] The epoxy equivalent of the epoxy resin is preferably 50 g / eq. to 5,000 g / eq., more preferably 60 g / eq. to 3,000 g / eq., still more preferably 80 g / eq. to 2,000 g / eq., and particularly preferably 110 g / eq. to 1,000 g / eq. The epoxy equivalent represents the mass of the resin per equivalent of epoxy groups. This epoxy equivalent can be measured according to JIS K7236.

[0048] The weight average molecular weight (Mw) of the epoxy resin is preferably 100 to 5,000, more preferably 250 to 3,000, and still more preferably 400 to 1,500. The weight average molecular weight can be measured as a value in terms of polystyrene by the gel permeation chromatography (GPC) method.

[0049] The range of the amount of the epoxy resin in the first resin composition is preferably 0.1% by mass or more, more preferably 1% by mass or more, still more preferably 3% by mass or more, and preferably 30% by mass or less, more preferably 20% by mass or less, still more preferably 15% by mass or less, based on 100% by mass of the non-volatile components in the first resin composition.

[0050] The range of the amount of the epoxy resin in the first resin composition is preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass or more, and preferably 80% by mass or less, more preferably 70% by mass or less, still more preferably 60% by mass or less, based on 100% by mass of the resin components in the first resin composition. The "resin components" in the first resin composition refers to the components excluding the inorganic filler among the non-volatile components contained in the first resin composition, unless otherwise specified.

[0051] Examples of the curing agent include active ester resins, phenolic resins, carbodiimide resins, acid anhydride resins, benzoxazine resins, cyanate ester resins, amine resins, thiol resins, and the like. The curing agent may be used alone or in combination of two or more.

[0052] As the active ester resin, a resin having one or more, preferably two or more active ester groups in one molecule can be used. Among them, as the active ester resin, a resin having two or more highly reactive ester groups such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds in one molecule is preferable.

[0053] The active ester resin is preferably obtained by a condensation reaction of a carboxylic acid compound and / or a thiocarboxylic acid compound with a hydroxy compound and / or a thiol compound. Particularly from the viewpoint of improving heat resistance, an active ester resin obtained from a carboxylic acid compound and a hydroxy compound is preferred, and an active ester resin obtained from a carboxylic acid compound and a phenol compound and / or a naphthol compound is more preferred. Examples of the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, and the like. Examples of the phenol compound or naphthol compound include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalin, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadiene type diphenol compound, phenol novolak, and the like. Here, the "dicyclopentadiene type diphenol compound" refers to a diphenol compound obtained by condensing two molecules of phenol with one molecule of dicyclopentadiene.

[0054] Specifically, as the active ester resin, a dicyclopentadiene type active ester resin, a naphthalene type active ester resin containing a naphthalene structure, an active ester resin containing an acetylated product of phenol novolak, and an active ester resin containing a benzoylated product of phenol novolak are preferred, and among them, the dicyclopentadiene type active ester resin is more preferred. As the dicyclopentadiene type active ester resin, an active ester resin containing a dicyclopentadiene type diphenol structure is preferred.

[0055] Examples of commercially available active ester resins include, for example, as active ester resins containing a dicyclopentadiene-type diphenol structure, "EXB9451", "EXB9460", "EXB9460S", "EXB-8000L", "EXB-8000L-65M", "EXB-8000L-65TM", "HPC-8000L-65TM", "HPC-8000", "HPC-8000-65T", "HPC-8000H", "HPC-8000H-65TM" (manufactured by DIC Corporation); as active ester resins containing a naphthalene structure, "HP-B-8151-62T", "EXB-8100L-65T", "EXB-8150-60T", "EXB-8150-62T", "EXB-9416-70BK", "HPC-8150-60T", "HPC-8150-62T", "EXB-8" (manufactured by DIC Corporation); as phosphorus-containing active ester resins, "EXB9401" (manufactured by DIC Corporation); as active ester resins that are acetylated products of phenol novolac, "DC808" (manufactured by Mitsubishi Chemical Corporation); as active ester resins that are benzoylated products of phenol novolac, "YLH1026", "YLH1030", "YLH1048" (manufactured by Mitsubishi Chemical Corporation); as active ester resins containing a styryl group and a naphthalene structure, "PC1300-02-65MA" (manufactured by Air Water, Inc.), and the like.

[0056] As the phenolic resin, a resin having one or more, preferably two or more, hydroxyl groups (phenolic hydroxyl groups) bonded to an aromatic ring such as a benzene ring or a naphthalene ring in one molecule can be used. From the viewpoints of heat resistance and water resistance, a phenolic resin having a novolac structure is preferred. Also, from the viewpoint of adhesion, a nitrogen-containing phenolic resin may be used, for example, a phenolic resin containing a triazine skeleton may be used. To give a specific example, from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion, a phenolic novolac resin containing a triazine skeleton may be used.

[0057] Specific examples of phenolic resins include "MEH-7700", "MEH-7810", "MEH-7851", "MEH-8000H" manufactured by Meiwa Kasei Co., Ltd.; "NHN", "CBN", "GPH" manufactured by Nippon Kayaku Co., Ltd.; "SN-170", "SN-180", "SN-190", "SN-475", "SN-485", "SN-495", "SN-495V", "SN-375", "SN-395" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "TD-2090", "TD-2090-60M", "LA-7052", "LA-7054", "LA-1356", "LA-3018", "LA-3018-50P", "LA-1356", "TD2090", "TD-2090-60M", "KA-1160" manufactured by DIC Corporation; "GDP-6115L", "GDP-6115H", "ELPC75", etc. manufactured by Gunei Chemical Industry Co., Ltd.

[0058] As the carbodiimide resin, a resin having one or more, preferably two or more carbodiimide structures in one molecule can be used. Specific examples of the carbodiimide resin include aliphatic biscarbodiimides such as tetramethylene-bis(t-butylcarbodiimide) and cyclohexane bis(methylene-t-butylcarbodiimide); biscarbodiimides such as aromatic biscarbodiimides such as phenylene-bis(xilylcarbodiimide); aliphatic polycarbodiimides such as polyhexamethylene carbodiimide, polytrimethylhexamethylene carbodiimide, polycyclohexylene carbodiimide, poly(methylenebiscyclohexylene carbodiimide), and poly(isophorone carbodiimide); aromatic polycarbodiimides such as poly(phenylene carbodiimide), poly(naphthylene carbodiimide), poly(tolylene carbodiimide), poly(methyldiisopropylphenylene carbodiimide), poly(triethylphenylene carbodiimide), poly(diethylphenylene carbodiimide), poly(triisopropylphenylene carbodiimide), poly(diisopropylphenylene carbodiimide), poly(xylene carbodiimide), poly(tetramethylxylene carbodiimide), poly(methylenediphenylene carbodiimide), and poly[methylenebis(methylphenylene) carbodiimide]. Commercially available products of the carbodiimide resin include, for example, "Carbodilite V-02B", "Carbodilite V-03", "Carbodilite V-04K", "Carbodilite V-05", "Carbodilite V-07", and "Carbodilite V-09" manufactured by Nisshinbo Chemical Inc.; "Stabaxol P", "Stabaxol P400", "Highcadil 510", etc. manufactured by LANXESS Corporation.

[0059] As the acid anhydride-based resin, a resin having one or more, preferably two or more acid anhydride groups in one molecule can be used. Specific examples of the acid anhydride-based resin include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenylsulfone tetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione, ethylene glycol bis(anhydrotrimellitate), and polymer-type acid anhydrides such as a styrene-maleic acid resin copolymerized from styrene and maleic acid. Commercially available products of the acid anhydride-based resin include, for example, "HNA-100", "MH-700", "MTA-15", "DDSA", "OSA" manufactured by Shin Nippon Rika Co., Ltd.; "YH-306", "YH-307" manufactured by Mitsubishi Chemical Corporation; "HN-2200", "HN-5500" manufactured by Resonaak Co., Ltd.; "EF-30", "EF-40", "EF-60", "EF-80" manufactured by Cray Valley Co., Ltd., and the like.

[0060] As the benzoxazine-based resin, a resin having one or more, preferably two or more benzoxazine rings in one molecule can be used. Specific examples of the benzoxazine-based resin include "JBZ-OP100D", "ODA-BOZ" manufactured by JFE Chemical Corporation; "HFB2006M" manufactured by Showa Highpolymer Co., Ltd.; "P-d", "F-a" manufactured by Shikoku Kasei Kogyo Co., Ltd., and the like.

[0061] As the cyanate ester resin, a resin having one or more, preferably two or more cyanate groups in one molecule can be used. Examples of the cyanate ester resin include bifunctional cyanate ester resins such as bisphenol A dicyanate, polyphenol cyanate, oligo(3-methylene-1,5-phenylene cyanate), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethylidenediphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanatephenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanatephenyl-1-(methylethylidene))benzene, bis(4-cyanatephenyl)thioether, and bis(4-cyanatephenyl)ether; polyfunctional cyanate ester resins derived from phenol novolac and cresol novolac; prepolymers in which part of these cyanate ester resins is triazinized; and the like. Specific examples of the cyanate ester resin include "PT30" and "PT60" (phenol novolac type polyfunctional cyanate ester resins), "BA230", and "BA230S75" (prepolymers in which part or all of bisphenol A dicyanate is triazinized to form trimers) manufactured by Lonza.

[0062] As the amine resin, a resin having one or more, preferably two or more amino groups in one molecule can be used. Examples of the amine resin include aliphatic amines, polyether amines, alicyclic amines, aromatic amines, etc. Among them, aromatic amines are preferred. The amine resin is preferably a primary amine or a secondary amine, and more preferably a primary amine. Specific examples of the amine resin include 4,4'-methylenebis(2,6-dimethylaniline), 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, m-phenylenediamine, m-xylylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, 2,2-bis(3-amino-4-hydroxyphenyl)propane, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethanediamine, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, bis(4-(3-aminophenoxy)phenyl)sulfone, etc. Commercially available products of the amine resin include, for example, "SEIKACURE-S" manufactured by Seika Corporation; "KAYABOND C-200S", "KAYABOND C-100", "KAYAHARD A-A", "KAYAHARD A-B", "KAYAHARD A-S" manufactured by Nippon Kayaku Co., Ltd.; "EPICURE W" manufactured by Mitsubishi Chemical Corporation; "DTDA" manufactured by Sumitomo Seika Chemicals Co., Ltd., etc.

[0063] Examples of the thiol resin include trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), tris(3-mercaptopropyl)isocyanurate, etc.

[0064] The active group equivalent weight of the curing agent is preferably from 50 g / eq. to 3000 g / eq., more preferably from 100 g / eq. to 1000 g / eq., still more preferably from 100 g / eq. to 500 g / eq., and particularly preferably from 100 g / eq. to 300 g / eq. The active group equivalent weight represents the mass of the resin per equivalent of the active group.

[0065] In one example, the range of the weight average molecular weight (Mw) of the curing agent may be the same as the range of the weight average molecular weight (Mw) of the epoxy resin.

[0066] The range of the amount of the curing agent in the first resin composition is preferably 0.1% by mass or more, more preferably 1% by mass or more, still more preferably 3% by mass or more, and preferably 30% by mass or less, more preferably 20% by mass or less, still more preferably 15% by mass or less, based on 100% by mass of the non-volatile components in the first resin composition.

[0067] The range of the amount of the curing agent in the first resin composition is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more, and preferably 80% by mass or less, more preferably 70% by mass or less, still more preferably 60% by mass or less, based on 100% by mass of the resin component in the first resin composition.

[0068] When the first resin composition contains a combination of an epoxy resin and a curing agent, the range of the number of active groups of the curing agent with respect to the number of epoxy groups of 1 of the epoxy resin is preferably 0.1 or more, more preferably 0.3 or more, still more preferably 0.5 or more, and preferably 3.0 or less, more preferably 2.5 or less, and particularly preferably 2.0 or less. The "number of epoxy groups of the epoxy resin" in the first resin composition represents the total value obtained by summing up the values obtained by dividing the mass of the non-volatile components of the epoxy resin present in the first resin composition by the epoxy equivalent weight. Also, the "number of active groups of the curing agent" in the first resin composition represents the total value obtained by summing up the values obtained by dividing the mass of the non-volatile components of the curing agent present in the first resin composition by the active group equivalent weight.

[0069] As the radical polymerizable resin, a resin containing an ethylenically unsaturated bond can be used. Therefore, the radical polymerizable resin usually may have a radical polymerizable group containing an ethylenically unsaturated bond. Examples of the radical polymerizable group include unsaturated hydrocarbon groups such as vinyl group, allyl group, 1-propenyl group, 3-cyclohexenyl group, 3-cyclopentenyl group, 2-vinylphenyl group, 3-vinylphenyl group, 4-vinylphenyl group; α,β-unsaturated carbonyl groups such as acryloyl group, methacryloyl group, maleimide group (2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl group), and the like. The radical polymerizable resin preferably has two or more radical polymerizable groups.

[0070] Examples of the radical polymerizable resin include (meth)acrylic radical polymerizable resins, styrene radical polymerizable resins, allyl radical polymerizable resins, maleimide radical polymerizable resins, and the like. The radical polymerizable resin may be used alone or in combination of two or more.

[0071] (Meth)acrylic radical polymerizable resins include resins having one or more, preferably two or more acryloyl groups and / or methacryloyl groups in one molecule. Examples of (meth)acrylic radical polymerizable resins include low molecular weight (molecular weight less than 1000) aliphatic (meth)acrylate compounds such as cyclohexane-1,4-dimethanol di(meth)acrylate, cyclohexane-1,3-dimethanol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, glycerin tri(meth)acrylate, pentaerythritol tetra(meth)acrylate; low molecular weight (molecular weight less than 1000) ether-containing (meth)acrylate compounds such as dioxane glycol di(meth)acrylate, 3,6-dioxa-1,8-octanediol di(meth)acrylate, 3,6,9-trioxaundecane-1,11-diol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, ethoxylated bisphenol A di(meth)acrylate, propoxylated bisphenol A di(meth)acrylate; low molecular weight (molecular weight less than 1000) isocyanurate-containing (meth)acrylate compounds such as tris(3-hydroxypropyl)isocyanurate tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, ethoxylated isocyanuric acid tri(meth)acrylate; high molecular weight (molecular weight 1000 or more) acrylate compounds such as (meth)acrylic-modified polyphenylene ether resin, and the like.Examples of commercially available (meth)acrylic radical polymerizable resins include "A-DOG" (dioxane glycol diacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd., "DCP-A" (tricyclodecane dimethanol diacrylate), "DCP" (tricyclodecane dimethanol dimethacrylate), "BPE-1300N" (ethoxylated bisphenol A dimethacrylate) manufactured by Kyoeisha Chemical Co., Ltd., "KAYARAD R-684" (tricyclodecane dimethanol diacrylate), "KAYARAD R-604" (dioxane glycol diacrylate) manufactured by Nippon Kayaku Co., Ltd., "SA9000", "SA9000-111" (methacryl-modified polyphenylene ether) manufactured by SABIC, etc.

[0072] As the styrene-based radical polymerizable resin, a resin having one or more, preferably two or more vinyl groups directly bonded to an aromatic carbon atom in one molecule can be used. Examples of the styrene-based radical polymerizable resin include low molecular weight (molecular weight less than 1000) styrene-based compounds such as divinylbenzene, 2,4-divinyltoluene, 2,6-divinylnaphthalene, 1,4-divinylnaphthalene, 4,4'-divinylbiphenyl, 1,2-bis(4-vinylphenyl)ethane, 2,2-bis(4-vinylphenyl)propane, bis(4-vinylphenyl)ether; high molecular weight (molecular weight 1000 or more) styrene-based compounds such as vinylbenzyl-modified polyphenylene ether resin, styrene-divinylbenzene copolymer, etc. Examples of commercially available styrene-based radical polymerizable resins include "ODV-XET(X03)", "ODV-XET(X04)", "ODV-XET(X05)" (styrene-divinylbenzene copolymer) manufactured by Nippon Steel Chemical & Material Co., Ltd., "OPE-2St 1200", "OPE-2St 2200" (vinylbenzyl-modified polyphenylene ether resin) manufactured by Mitsubishi Gas Chemical Company, Inc.

[0073] As the allyl radical-polymerizable resin, a resin having one or more, preferably two or more allyl groups in one molecule can be used. Examples of the allyl radical-polymerizable resin include aromatic carboxylic acid allyl ester compounds such as diallyl diphenate, triallyl trimellitate, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, diallyl 2,6-naphthalenedicarboxylate, and diallyl 2,3-naphthalenedicarboxylate; allyl ester compounds of isocyanuric acid such as 1,3,5-triallyl isocyanurate and 1,3-diallyl-5-glycidyl isocyanurate; epoxy-containing aromatic allyl compounds such as 2,2-bis[3-allyl-4-(glycidyloxy)phenyl]propane; benzoxazine-containing aromatic allyl compounds such as bis[3-allyl-4-(3,4-dihydro-2H-1,3-benzoxazin-3-yl)phenyl]methane; ether-containing aromatic allyl compounds such as 1,3,5-triallyl ether benzene; and allyl silane compounds such as diallyl diphenyl silane. Commercially available products of the allyl radical-polymerizable resin include, for example, "TAIC" (1,3,5-triallyl isocyanurate) manufactured by Nippon Kasei Co., Ltd., "DAD" (diallyl diphenate) manufactured by Nisshoku Techno Fine Chemical Co., Ltd., "TRIAM-705" (triallyl trimellitate) manufactured by Fujifilm Wako Pure Chemical Corporation, the product name "DAND" (diallyl 2,3-naphthalenedicarboxylate) manufactured by Nisshoku Techno Fine Chemical Co., Ltd., "ALP-d" (bis[3-allyl-4-(3,4-dihydro-2H-1,3-benzoxazin-3-yl)phenyl]methane) manufactured by Shikoku Kasei Kogyo Co., Ltd., "RE-810NM" (2,2-bis[3-allyl-4-(glycidyloxy)phenyl]propane) manufactured by Nippon Kayaku Co., Ltd., "DA-MGIC" (1,3-diallyl-5-glycidyl isocyanurate) manufactured by Shikoku Kasei Kogyo Co., Ltd., and the like.

[0074] As the maleimide-based radically polymerizable resin, a resin having one or more, preferably two or more maleimide groups in one molecule can be used. The maleimide-based radically polymerizable resin may be an aromatic maleimide resin having a maleimide group directly bonded to an aromatic ring, or may be an aliphatic maleimide resin having no maleimide group directly bonded to an aromatic ring. Examples of commercially available maleimide-based radically polymerizable resins include "SLK-2600" manufactured by Shin-Etsu Chemical Co., Ltd., "BMI-1500", "BMI-1700", "BMI-3000J", "BMI-689", "BMI-2500" (maleimide compound containing a dimer diamine structure) manufactured by Designer Molecules Inc., "BMI-6100" (aromatic maleimide compound) manufactured by Designer Molecules Inc., "MIR-5000-60T", "MIR-3000-70MT" (biphenyl aralkyl type maleimide compound) manufactured by Nippon Kayaku Co., Ltd., "BMI-70", "BMI-80" manufactured by K.I. Kasei Co., Ltd., "BMI-2300", "BMI-TMH" manufactured by Daiwa Kasei Kogyo Co., Ltd., and the like. Further, as the maleimide-based radically polymerizable resin, a maleimide resin (maleimide compound containing an indane ring skeleton) disclosed in Invention Association Public Technical Report Publication No. 2020-500211 may be used.

[0075] The radical polymerization equivalent weight of the radically polymerizable resin is preferably 20 g / eq. to 3,000 g / eq., more preferably 50 g / eq. to 2,500 g / eq., still more preferably 70 g / eq. to 2,000 g / eq., and particularly preferably 90 g / eq. to 1,500 g / eq. The radical polymerization equivalent weight represents the mass of the radically polymerizable resin per equivalent of the radical polymerization group.

[0076] The weight average molecular weight (Mw) of the radically polymerizable resin is preferably 40,000 or less, more preferably 10,000 or less, still more preferably 5,000 or less, and particularly preferably 3,000 or less. The lower limit is not particularly limited, but can be, for example, 150 or more. The weight average molecular weight can be measured as a value in terms of polystyrene by gel permeation chromatography (GPC) method.

[0077] The range of the amount of the radically polymerizable resin in the first resin composition is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, still more preferably 1% by mass or more, and preferably 20% by mass or less, more preferably 10% by mass or less, still more preferably 5% by mass or less, based on 100% by mass of the non-volatile components in the first resin composition.

[0078] The range of the amount of the radically polymerizable resin in the first resin composition is preferably 1% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less, based on 100% by mass of the resin components in the first resin composition.

[0079] The range of the amount of the (B) first curable resin in the first resin composition is preferably 1% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less, based on 100% by mass of the non-volatile components in the first resin composition.

[0080] The range of the amount of the (B) first curable resin in the first resin composition is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, and preferably 100% by mass or less, more preferably 99% by mass or less, still more preferably 98% by mass or less, based on 100% by mass of the resin components in the first resin composition.

[0081] The range of the total amount of the (A) first inorganic filler and the (B) first curable resin in the first resin composition is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, based on 100% by mass of the non-volatile components in the first resin composition. The upper limit is usually 100% by mass or less, and may be, for example, 99% by mass or less or 98% by mass or less.

[0082] (Description of (C) polymer resin) The first resin composition may contain, as an optional component, (C) a high molecular weight resin. The (C) high molecular weight resin usually has thermoplasticity and is contained in the first resin composition in a state compatible with resin components other than the (C) high molecular weight resin. The (C) high molecular weight resin as the component (C) does not include those corresponding to the above-mentioned components (A) to (B). Also, the (C) high molecular weight resin may be used alone or in combination of two or more kinds.

[0083] Examples of the (C) high molecular weight resin include phenoxy resin, acrylic resin, polyimide resin, polyvinyl acetal resin, polyolefin resin, polybutadiene resin, polyamideimide resin, polyetherimide resin, polysulfone resin, polyethersulfone resin, polyphenylene ether resin, polycarbonate resin, polyetheretherketone resin, polyester resin, and the like.

[0084] Examples of the phenoxy resin include phenoxy resins having one or more skeletons selected from the group consisting of bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenol acetophenone skeleton, novolak skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, terpene skeleton, and trimethylcyclohexane skeleton. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. Specific examples of the phenoxy resin include "1256" and "4250" (both bisphenol A skeleton-containing phenoxy resins) manufactured by Mitsubishi Chemical Corporation; "YX8100" (bisphenol S skeleton-containing phenoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX6954" (bisphenol acetophenone skeleton-containing phenoxy resin) manufactured by Mitsubishi Chemical Corporation; "FX280" and "FX293" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YL7500BH30", "YX6954BH30", "YX7553", "YX7553BH30", "YL7769BH30", "YL6794", "YL7213", "YL7290", "YL7482", and "YL7891BH30" manufactured by Mitsubishi Chemical Corporation; and the like.

[0085] Examples of the acrylic resin include resins containing a (meth)acrylate structure. The acrylic resin may contain the (meth)acrylate structure in the main chain or in the side chain. Here, the term "(meth)acrylate structure" includes both an acrylate structure and a methacrylate structure. Specific examples of the acrylic resin include Teisan Resin "SG-70L", "SG-708-6", "WS-023", "SG-700AS", "SG-280TEA", "SG-80H", "SG-80H-3", "SG-P3", "SG-600TEA", "SG-790" manufactured by Nagase ChemteX Corporation; "ME-2000", "W-116.3", "W-197C", "KG-25", "KG-3000" manufactured by Negami Kogyo Co., Ltd.; "ARUFON UH-2000" manufactured by Toagosei Co., Ltd., and the like.

[0086] Specific examples of the polyimide resin include "SLK-6100" manufactured by Shin-Etsu Chemical Co., Ltd., "Ricacote SN20" and "Ricacote PN20" manufactured by Nippon Rika Kasei Co., Ltd., and the like. Specific examples of the polyimide resin also include modified polyimides such as linear polyimide obtained by reacting bifunctional hydroxyl group-terminated polybutadiene, diisocyanate compound, and tetracarboxylic dianhydride (the polyimide described in JP-A-2006-37083), polyimide containing a polysiloxane skeleton (the polyimide described in JP-A-2002-12667 and JP-A-2000-319386), and the like.

[0087] Examples of the polyvinyl acetal resin include polyvinyl formal resin and polyvinyl butyral resin, and polyvinyl butyral resin is preferred. Specific examples of the polyvinyl acetal resin include the Esrec BH series, BX series (e.g., BX-5Z), KS series (e.g., KS-1), BL series, BM series manufactured by Sekisui Chemical Co., Ltd., and the like.

[0088] Examples of the polyolefin resin include ethylene-based copolymer resins such as low-density polyethylene, ultra-low density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-methyl acrylate copolymer; and polyolefin polymers such as polypropylene and ethylene-propylene block copolymer.

[0089] Examples of the polybutadiene resin include a hydrogenated polybutadiene skeleton-containing resin, a hydroxy group-containing polybutadiene resin, a phenolic hydroxyl group-containing polybutadiene resin, a carboxy group-containing polybutadiene resin, an acid anhydride group-containing polybutadiene resin, an epoxy group-containing polybutadiene resin, an isocyanate group-containing polybutadiene resin, a urethane group-containing polybutadiene resin, a polyphenylene ether-polybutadiene resin, and the like. Part or all of the polybutadiene structure of the polybutadiene resin may be hydrogenated. Specific examples of the polybutadiene resin include "Ricon 130MA8", "Ricon 130MA13", "Ricon 130MA20", "Ricon 131MA5", "Ricon 131MA10", "Ricon 131MA17", "Ricon 131MA20", "Ricon 184MA6" (acid anhydride group-containing polybutadiene) manufactured by Kray Valley; "GQ-1000" (hydroxy group and carboxyl group-introduced polybutadiene), "G-1000", "G-2000", "G-3000" (both-terminal hydroxy group polybutadiene), "GI-1000", "GI-2000", "GI-3000" (both-terminal hydroxy group hydrogenated polybutadiene) manufactured by Nippon Soda Co., Ltd.; "FCA-061L" (hydrogenated polybutadiene skeleton epoxy resin) manufactured by Nagase ChemteX Corporation, and the like. Further, specific examples of the polybutadiene resin include a polyimide resin having a polybutadiene structure, a urethane structure and an imide structure in the molecule. The polyimide resin can be produced as a linear polyimide resin (the polyimide described in JP-A-2006-37083 and WO 2008 / 153208) using a hydroxyl group-terminated polybutadiene, a diisocyanate compound and a tetracarboxylic dianhydride as raw materials. The content of the butadiene structure in the polyimide resin is preferably 60% by mass to 95% by mass, more preferably 75% by mass to 85% by mass. Details of the polyimide resin can be referred to the descriptions in JP-A-2006-37083 and WO 2008 / 153208, and this content is incorporated herein.

[0090] Specific examples of polyamide-imide resins include "Vylon Max HR11NN" and "Vylon Max HR16NN" manufactured by Toyobo Co., Ltd. Specific examples of polyamide-imide resins also include modified polyamide-imides such as "KS9100" and "KS9300" (polyamide-imide containing a polysiloxane skeleton) manufactured by Hitachi Chemical Co., Ltd.

[0091] Specific examples of polyetherimide resins include "Ultem" manufactured by GE Corporation.

[0092] Specific examples of polysulfone resins include polysulfones "P1700", "P3500", etc. manufactured by Solvay Advanced Polymers, LLC.

[0093] Specific examples of polyethersulfone resins include "PES5003P" manufactured by Sumitomo Chemical Co., Ltd.

[0094] Specific examples of polyphenylene ether resins include "NORYL SA90" manufactured by SABIC and oligophenylene ether-styrene resin "OPE-2St 1200" manufactured by Mitsubishi Gas Chemical Company, Inc.

[0095] Examples of the polycarbonate resin include a hydroxyl group-containing carbonate resin, a phenolic hydroxyl group-containing carbonate resin, a carboxyl group-containing carbonate resin, an acid anhydride group-containing carbonate resin, an isocyanate group-containing carbonate resin, a urethane group-containing carbonate resin, and the like. Specific examples of the polycarbonate resin include "FPC0220" manufactured by Mitsubishi Gas Chemical Company, "T6002", "T6001" (polycarbonate diol) manufactured by Asahi Kasei Corporation, "C-1090", "C-2090", "C-3090" (polycarbonate diol) manufactured by Kuraray Co., Ltd., and the like. Further, specific examples of the polycarbonate resin include a polyimide resin having an imide structure, a urethane structure, and a polycarbonate structure in the molecule. The polyimide resin can be produced as a linear polyimide resin using a hydroxyl group-terminated polycarbonate, a diisocyanate compound, and a tetracarboxylic acid anhydride as raw materials. The content of the carbonate structure in the polyimide resin is preferably 60% by mass to 95% by mass, more preferably 75% by mass to 85% by mass. Details of the polyimide resin can be referred to the description in International Publication No. 2016 / 129541, and this content is incorporated herein.

[0096] Specific examples of the polyetheretherketone resin include "Sumipro EK" manufactured by Sumitomo Chemical Company, and the like.

[0097] Examples of the polyester resin include a polyethylene terephthalate resin, a polyethylene naphthalate resin, a polybutylene terephthalate resin, a polybutylene naphthalate resin, a polytrimethylene terephthalate resin, a polytrimethylene naphthalate resin, a polycyclohexanedimethylene terephthalate resin, and the like.

[0098] (C) The polymer resin usually has a large molecular weight. Specifically, the range of the weight-average molecular weight Mw of the (C) polymer resin is preferably greater than 5,000, more preferably 8,000 or more, still more preferably 10,000 or more, and even more preferably 20,000 or more, and is preferably 100,000 or less, more preferably 70,000 or less, still more preferably 60,000 or less, and even more preferably 50,000 or less. The weight-average molecular weight Mw can be measured as a polystyrene-equivalent value by gel permeation chromatography (GPC).

[0099] The range of the amount of the (C) polymer resin in the first resin composition is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 1% by mass or more, and preferably 20% by mass or less, more preferably 10% by mass or less, still more preferably 5% by mass or less, based on 100% by mass of the non-volatile components in the first resin composition.

[0100] The range of the amount of the (C) polymer resin in the first resin composition is preferably 1% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, and preferably 40% by mass or less, more preferably 30% by mass or less, still more preferably 20% by mass or less, based on 100% by mass of the resin components in the first resin composition.

[0101] (Description of (D) curing accelerator) The first resin composition may contain, as an optional component, a (D) curing accelerator. Since the (D) curing accelerator can act as a catalyst for the reaction of the (B) first curable resin, it can accelerate the curing of the first resin composition. The (D) curing accelerator as the (D) component does not include those corresponding to the above-mentioned (A) to (C) components. Also, the (D) curing accelerator may be used alone or in combination of two or more.

[0102] (D) As the curing accelerator, an appropriate one can be used according to the type of (B) the first curable resin. For example, when (B) the first curable resin contains an epoxy resin, examples of the (D) curing accelerator that can accelerate the curing of the epoxy resin include phosphorus-based curing accelerators, urea-based curing accelerators, guanidine-based curing accelerators, imidazole-based curing accelerators, metal-based curing accelerators, amine-based curing accelerators, and the like.

[0103] Examples of phosphorus-based curing accelerators include aliphatic phosphonium salts such as tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium laurate, bis(tetrabutylphosphonium) pyromellitate, tetrabutylphosphonium hydrogen hexahydrophthalate, tetrabutylphosphonium 2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenolate, di-tert-butyldimethylphosphonium tetraphenylborate; aromatic phosphonium salts such as methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, propyltriphenylphosphonium bromide, butyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, tetraphenylphosphonium bromide, p-tolyltriphenylphosphonium tetra-p-tolylborate, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, triphenylethylphosphonium tetraphenylborate, tris(3-methylphenyl)ethylphosphonium tetraphenylborate, tris(2-methoxyphenyl)ethylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate; aromatic phosphine-borane complexes such as triphenylphosphine·triphenylborane; aromatic phosphine-quinone addition reactants such as triphenylphosphine·p-benzoquinone addition reactant; aliphatic phosphines such as tributylphosphine, tri-tert-butylphosphine, trioctylphosphine, di-tert-butyl(2-butenyl)phosphine, di-tert-butyl(3-methyl-2-butenyl)phosphine, tricyclohexylphosphine;Aromatic phosphines such as dibutylphenylphosphine, di-tert-butylphenylphosphine, methyldiphenylphosphine, ethyldiphenylphosphine, butyldiphenylphosphine, diphenylcyclohexylphosphine, triphenylphosphine, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tris(4-ethylphenyl)phosphine, tris(4-propylphenyl)phosphine, tris(4-isopropylphenyl)phosphine, tris(4-butylphenyl)phosphine, tris(4-tert-butylphenyl)phosphine, tris(2,4-dimethylphenyl)phosphine, tris(2,5-dimethylphenyl)phosphine, tris(2,6-dimethylphenyl)phosphine, tris(3,5-dimethylphenyl)phosphine, tris(2,4,6-trimethylphenyl)phosphine, tris(2,6-dimethyl-4-ethoxyphenyl)phosphine, tris(2-methoxyphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(4-ethoxyphenyl)phosphine, tris(4-tert-butoxyphenyl)phosphine, diphenyl-2-pyridylphosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,2-bis(diphenylphosphino)acetylene, 2,2'-bis(diphenylphosphino)diphenylether, etc. are mentioned.;

[0104] Examples of the urea-based curing accelerators include aliphatic dimethylureas such as 1,1-dimethylurea; 1,1,3-trimethylurea, 3-ethyl-1,1-dimethylurea, 3-cyclohexyl-1,1-dimethylurea, 3-cyclooctyl-1,1-dimethylurea; and aromatic dimethylureas such as 3-phenyl-1,1-dimethylurea, 3-(4-chlorophenyl)-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea, 3-(2-methylphenyl)-1,1-dimethylurea, 3-(4-methylphenyl)-1,1-dimethylurea, 3-(3,4-dimethylphenyl)-1,1-dimethylurea, 3-(4-isopropylphenyl)-1,1-dimethylurea, 3-(4-methoxyphenyl)-1,1-dimethylurea, 3-(4-nitrophenyl)-1,1-dimethylurea, 3-[4-(4-methoxyphenoxy)phenyl]-1,1-dimethylurea, 3-[4-(4-chlorophenoxy)phenyl]-1,1-dimethylurea, 3-[3-(trifluoromethyl)phenyl]-1,1-dimethylurea, N,N-(1,4-phenylene)bis(N’,N’-dimethylurea), N,N-(4-methyl-1,3-phenylene)bis(N’,N’-dimethylurea) [toluene bisdimethylurea].

[0105] Examples of the guanidine-based curing accelerators include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, 1-phenylbiguanide, 1-(o-tolyl)biguanide.

[0106] Examples of imidazole-based curing accelerators include imidazole compounds such as 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, 2-phenylimidazoline, and adducts of imidazole compounds and epoxy resins. Commercially available products of imidazole-based curing accelerators include, for example, "1B2PZ", "2E4MZ", "2MZA-PW", "2MZ-OK", "2MA-OK", "2MA-OK-PW", "2PHZ", "2PHZ-PW", "Cl1Z", "Cl1Z-CN", "Cl1Z-CNS", "C11Z-A" manufactured by Shikoku Kasei Kogyo Co., Ltd.; "P200-H50" manufactured by Mitsubishi Chemical Corporation, etc.

[0107] Examples of the metal-based hardening accelerator include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of the organometallic complex include organocobalt complexes such as cobalt(II) acetylacetonate and cobalt(III) acetylacetonate, organocopper complexes such as copper(II) acetylacetonate, organozinc complexes such as zinc(II) acetylacetonate, organoiron complexes such as iron(III) acetylacetonate, organonickel complexes such as nickel(II) acetylacetonate, and organomanganese complexes such as manganese(II) acetylacetonate. Examples of the organometallic salt include zinc octylate, tin octylate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

[0108] Examples of the amine-based hardening accelerator include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclo(5,4,0)-undecene, etc. As the amine-based hardening accelerator, commercially available products may be used. For example, "MY-25" manufactured by Ajinomoto Fine-Techno Co., Inc. etc. may be mentioned.

[0109] The range of the amount of the (D) hardening accelerator in the first resin composition is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, still more preferably 0.02% by mass or more, and preferably 2% by mass or less, more preferably 1% by mass or less, still more preferably 0.5% by mass or less with respect to 100% by mass of the non-volatile components in the first resin composition.

[0110] The range of the amount of the (D) hardening accelerator in the first resin composition is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, still more preferably 0.1% by mass or more, and preferably 10% by mass or less, more preferably 8% by mass or less, still more preferably 5% by mass or less with respect to 100% by mass of the resin components in the first resin composition.

[0111] (Explanation of the (E) adhesion aid) The first resin composition may contain, as an optional component, (E) an adhesion promoter. According to the (E) adhesion promoter, the adhesion strength between the cured product layer and the layer in contact with the cured product layer can be increased. The (E) adhesion promoter as the (E) component does not include those corresponding to the above-described components (A) to (D). Further, the (E) adhesion promoter may be used alone or in combination of two or more kinds.

[0112] (E) As the adhesion promoter, for example, γ-aminopropyldimethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, 3-methacryloxypropyldimethoxymethylsilane, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, dimethoxymethyl-3-piperidinopropylsilane, diethoxy-3-glycidoxypropylmethylsilane, N-(3-diethoxymethylsilylpropyl)succinimide, N-[3-(triethoxysilyl)propyl]phthalic acid, benzophenone-3,3'-bis(N-[3-triethoxysilyl]propylamide)-4,4'-dicarboxylic acid, benzene-1,4-bis(N-3-triethoxysilyl]propylamide)-2,Silane coupling agents such as 5-dicarboxylic acid, 3-(triethoxysilyl)propyl succinic anhydride, N-phenylaminopropyltrimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-(trialkoxysilyl)propyl succinic anhydride, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, mercaptomethyltrimethoxysilane, mercaptomethylmethyldimethoxysilane, 3-mercaptopropyldiethoxymethoxysilane, 3-mercaptopropylethoxydimethoxysilane, 3-mercaptopropyltripropoxysilane, 3-mercaptopropyldiethoxypropoxysilane, 3-mercaptopropylethoxydipropoxysilane, 3-mercaptopropyldimethoxypropoxysilane, 3-mercaptopropylmethoxydipropoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyldiethoxymethoxysilane, 2-mercaptoethylethoxydimethoxysilane, 2-mercaptoethyltripropoxysilane, 2-mercaptoethyltripropoxysilane, 2-mercaptoethylethoxydipropoxysilane, 2-mercaptoethyldimethoxypropoxysilane, 2-mercaptoethylmethoxydipropoxysilane, 4-mercaptobutyltrimethoxysilane, 4-mercaptobutyltriethoxysilane, 4-mercaptobutyltripropoxysilane, N-(3-triethoxysilylpropyl)urea, N-(3-trimethoxysilylpropyl)urea, and compounds having an aminotriazine ring and an ethoxysilyl group; aluminum-based adhesion aids such as aluminum tris(ethylacetoacetate), aluminum tris(acetylacetonate), and aluminum diisopropylate ethylacetoacetate. Among them, (E) as the adhesion aid, a silane coupling agent is preferred.,

[0113] (E) Examples of commercially available adhesion aids include "KBM-403" (3-glycidoxypropyltriethoxysilane), "KBM-803" (3-mercaptopropyltrimethoxysilane), "LS1375" (3-mercaptopropylmethyldimethoxysilane), and "LS3610" (N-(3-triethoxysilylpropyl)urea) manufactured by Shin-Etsu Chemical Co., Ltd.; "Silace S810" (3-mercaptopropyltrimethoxysilane) manufactured by Chisso Corporation; "SIM6475.0" (3-mercaptopropyltriethoxysilane), "SIM6474.0" (3-mercaptopropylmethyldimethoxysilane), "SIM6473.5C" (mercaptomethyltrimethoxysilane), "SIM6473.0" (mercaptomethylmethyldimethoxysilane), "SIU9055.0" (N-(3-triethoxysilylpropyl)urea), and "SIU9058.0" (N-(3-trimethoxysilylpropyl)urea) manufactured by Azmax Co., Ltd.; "VD-5" (a compound having an aminotriazine ring and an ethoxysilyl group) manufactured by Shikoku Kasei Kogyo Co., Ltd., and the like.

[0114] The range of the amount of the (E) adhesion aid in the first resin composition is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, still more preferably 0.05% by mass or more, and preferably 2% by mass or less, more preferably 1% by mass or less, still more preferably 0.5% by mass or less, based on 100% by mass of the non-volatile components in the first resin composition.

[0115] The range of the amount of the (E) adhesion aid in the first resin composition is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, still more preferably 0.1% by mass or more, and preferably 5% by mass or less, more preferably 2% by mass or less, still more preferably 1% by mass or less, based on 100% by mass of the resin components in the first resin composition.

[0116] (Description of (F) Flame Retardant) The first resin composition may contain, as an optional component, (F) a flame retardant. According to the (F) flame retardant, the flame retardancy of the cured product layer can be improved. The (F) flame retardant as the (F) component does not include those corresponding to the (A) to (E) components. Also, the (F) flame retardant may be used alone or in combination of two or more kinds.

[0117] Examples of the (F) flame retardant include phosphazene compounds, organic phosphorus-based flame retardants, organic nitrogen-containing phosphorus compounds, nitrogen compounds, silicone-based flame retardants, metal hydroxides, etc. Examples of commercially available (F) flame retardants include "SPH-100", "SPS-100", "SPB-100", "SPE-100" (phosphazenes) manufactured by Otsuka Chemical Co., Ltd.; "FP-100", "FP-110", "FP-300", "FP-400" (phosphazenes) manufactured by Fushimi Pharmaceutical Co., Ltd.; "HCA-NQ", "HCA-HQ", "HCA-HQ-HST" (phosphinic acid esters (containing phenolic hydroxyl groups)) manufactured by Sanko Co., Ltd.; "PX-200", "PX-201", "PX-202", "CR-733S", "CR-741", "CR-747" (phosphoric acid esters) manufactured by Daihachi Chemical Industry Co., Ltd., etc.

[0118] The range of the amount of the (F) flame retardant in the first resin composition is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, still more preferably 0.1% by mass or more, and preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 1% by mass or less, based on 100% by mass of the non-volatile components in the first resin composition.

[0119] The range of the amount of the (F) flame retardant in the first resin composition is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, still more preferably 1% by mass or more, and preferably 10% by mass or less, more preferably 8% by mass or less, still more preferably 5% by mass or less, based on 100% by mass of the resin components in the first resin composition.

[0120] (Explanation of (G) Optional Additives) The first resin composition may further contain (G) an optional additive as an optional component. The (G) optional additive as the component (G) does not include those corresponding to the above-mentioned components (A) to (F). Examples of the (G) optional additive include radical polymerization initiators such as peroxide-based radical polymerization initiators and azo-based radical polymerization initiators; organometallic compounds such as organic copper compounds, organic zinc compounds, and organic cobalt compounds; colorants such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium oxide, and carbon black; polymerization inhibitors such as hydroquinone, catechol, pyrogallol, and phenothiazine; leveling agents such as silicone-based leveling agents and acrylic polymer-based leveling agents; thickeners such as benton and montmorillonite; antifoaming agents such as silicone-based antifoaming agents, acrylic-based antifoaming agents, fluorine-based antifoaming agents, and vinyl resin-based antifoaming agents; ultraviolet absorbers such as benzotriazole-based ultraviolet absorbers; adhesion improvers such as urea silane; antioxidants such as hindered phenol-based antioxidants; fluorescent brighteners such as stilbene derivatives; surfactants such as fluorine-based surfactants and silicone-based surfactants; dispersants such as phosphate ester-based dispersants, polyoxyalkylene-based dispersants, acetylene-based dispersants, silicone-based dispersants, anionic dispersants, and cationic dispersants; stabilizers such as borate-based stabilizers, titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, and carboxylic anhydride-based stabilizers. The (G) optional additive may be used alone or in combination of two or more kinds.

[0121] ((Description of the (H) solvent)) The first resin composition may further contain (H) a solvent as an optional volatile component in combination with the non-volatile components such as the above-described components (A) to (G). Usually, an organic solvent is used as the (H) solvent. Examples of the organic solvent include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, and γ-butyrolactone; ether solvents such as tetrahydropyran, tetrahydrofuran, 1,4-dioxane, diethyl ether, diisopropyl ether, dibutyl ether, diphenyl ether, and anisole; alcohol solvents such as methanol, ethanol, propanol, butanol, and ethylene glycol; ether ester solvents such as 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl diglycol acetate, γ-butyrolactone, and methyl methoxypropionate; ester alcohol solvents such as methyl lactate, ethyl lactate, and methyl 2-hydroxyisobutyrate; ether alcohol solvents such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether (butyl carbitol); amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; sulfoxide solvents such as dimethyl sulfoxide; nitrile solvents such as acetonitrile and propionitrile; aliphatic hydrocarbon solvents such as hexane, cyclopentane, cyclohexane, and methylcyclohexane; aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene, and the like. The (H) solvent may be used alone or in combination of two or more.

[0122] The amount of the (H) solvent in the first resin composition for forming the first resin composition layer is preferably small. The amount of the (H) solvent in the first resin composition is preferably 10% by mass or less, more preferably 5% by mass or less, still more preferably 4% by mass or less, still more preferably 3% by mass or less, still more preferably 2% by mass or less, based on 100% by mass of the total amount of the first resin composition. The lower limit may be 0% by mass or may be 0.0001% by mass or more.

[0123] (Description of the properties of the first resin composition and its cured product) The first resin composition forms a cured product when cured. Hereinafter, the cured product of the first resin composition may be referred to as the "first cured product". The first cured layer is formed by this first cured product. During curing, usually heat is applied to the first resin composition, so among the components contained in the first resin composition, the (H) solvent as a volatile component can volatilize due to the heat during curing. Therefore, the first cured product may contain the non-volatile components of the first resin composition or reaction products thereof.

[0124] The first cured product can usually have a large elastic modulus G1. The range of the elastic modulus G1 of the first cured product is preferably 10 GPa or more, more preferably 12 GPa or more, still more preferably 14 GPa or more, and preferably 40 GPa or less, more preferably 30 GPa or less, still more preferably 20 GPa or less. When the first cured product has such a large elastic modulus G1, the warpage of the circuit board and the intermediate product during its manufacture can be effectively suppressed, and the manufacture of the circuit board can be carried out smoothly. Also, usually, the formation of polishing marks on the first cured layer can be suppressed, and resin clogging of the polishing apparatus can be suppressed, so the polishing of the first cured layer can be carried out smoothly.

[0125] The elastic modulus can be measured as the storage elastic modulus at 25°C by performing thermomechanical analysis using a dynamic mechanical analyzer under the measurement conditions of a frequency of 1 Hz and a heating rate of 5°C / min. When the sample is the first resin composition before curing, the first resin composition may be cured under the curing conditions of 180°C for 90 minutes to obtain a first cured product, and the elastic modulus G1 of the first cured product may be measured. As the specific measurement method of the elastic modulus, the method described in the <Elastic Modulus Measurement Test> of the examples described later can be adopted.

[0126] The elastic modulus of the first cured product can be adjusted, for example, by the composition of the first resin composition (for example, the type and amount of (A) the first inorganic filler, the type and amount of (B) the first curable resin, and the type and amount of any component such as (C) the polymer resin, etc.).

[0127] The first cured product can usually have a small dielectric loss tangent. The range of the dielectric loss tangent of the first cured product is preferably 0.020 or less, more preferably 0.010 or less, and still more preferably 0.005 or less. The lower limit has no particular limitation and can be, for example, 0.0001 or more. The dielectric loss tangent can be measured at a measurement frequency of 5.8 GHz and a measurement temperature of 23°C by the cavity resonance perturbation method. When the sample is the first resin composition before curing, the first resin composition may be cured under the curing conditions of 180°C for 90 minutes to obtain a first cured product, and the dielectric loss tangent of the first cured product may be measured. As the specific measurement method of the dielectric loss tangent, the method described in the <Dielectric Loss Tangent Measurement Test> of the examples described later can be adopted.

[0128] (Explanation of the manufacturing method of the first resin composition) The first resin composition can be manufactured by mixing the components that can be included in the first resin composition. The above-mentioned components may be mixed partially or entirely at the same time, or may be mixed in sequence. During the process of mixing each component, the temperature may be appropriately set, and thus, heating and / or cooling may be performed temporarily or throughout. Also, stirring or shaking may be performed during the process of mixing each component.

[0129] (Explanation of the method for forming the first resin composition layer) In step (I), a first resin composition layer may be formed on an inner layer base material as an example of the base material. The "inner layer base material" is a member serving as the base material of a circuit board, and examples thereof include a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, a thermosetting polyphenylene ether substrate, and the like. Further, the inner layer base material may have a conductor layer on one or both of its surfaces. Further, the conductor layer provided in the inner layer base material may be pattern-processed. The inner layer base material having a conductor layer (circuit) formed on one or both surfaces of the substrate may be referred to as an "inner layer circuit base material". Further, in the production of a circuit board, an intermediate product on which an insulating layer and / or a conductor layer is to be further formed is also included in the term "inner layer base material". Further, an inner layer base material provided with components such as semiconductor chips may be used.

[0130] Further, in step (I), a first resin composition layer may be formed on a temporary base material as an example of the base material. To give a specific example, components may be temporarily fixed on a removable temporary base material, and the first resin composition layer may be formed so as to embed the components. In this case, after curing the first resin composition layer in step (II) described later to form a first cured layer, the temporary base material is removed, whereby a first cured layer having the components embedded therein can be obtained. Such a removable temporary base material can be produced, for example, by laminating a substrate and a temporary fixing film. Examples of the substrate include a silicon wafer; a glass wafer; a glass substrate; a metal substrate such as copper, titanium, stainless steel, and cold-rolled steel sheet (SPCC); a substrate obtained by impregnating glass fibers with an epoxy resin or the like and subjecting it to a thermosetting treatment, such as an FR-4 substrate; a substrate made of a bismaleimide triazine resin such as a BT resin; and the like. Further, as the temporary fixing film, a film that can be peeled off from the components and can temporarily fix the components can be used, and examples thereof include "Revalpha" manufactured by Nitto Denko Corporation.

[0131] The formation of the first resin composition layer in step (I) may be carried out, for example, by compression molding (compression molding method). The compression molding method generally involves placing the base material and the first resin composition in a mold, applying pressure and, if necessary, heat to the first resin composition in the mold to form the first resin composition layer on the base material.

[0132] The compression molding method may be carried out, for example, as follows. Prepare an upper mold and a lower mold as the molds for compression molding. Apply the first resin composition to the base material. Attach the base material coated with the first resin composition to the lower mold. Then, clamp the upper mold and the lower mold, and apply heat and pressure to the first resin composition to perform compression molding.

[0133] Also, the compression molding method may be carried out, for example, as follows. Prepare an upper mold and a lower mold as the molds for compression molding. Place the first resin composition on the lower mold. Also, attach the base material to the upper mold. Then, clamp the upper mold and the lower mold so that the first resin composition placed on the lower mold contacts the base material attached to the upper mold, and apply heat and pressure to perform compression molding.

[0134] Furthermore, the compression molding method may be carried out, for example, by discharging the first resin composition filled in the cartridge into the mold, and applying heat and pressure in the mold to perform compression molding.

[0135] The molding conditions vary depending on the composition of the first resin composition. For example, the temperature of the mold during molding is preferably 80°C or higher, more preferably 100°C or higher, still more preferably 120°C or higher, and preferably 200°C or lower, more preferably 170°C or lower, still more preferably 150°C or lower. Also, the pressure applied during molding is preferably 1 MPa or higher, more preferably 3 MPa or higher, still more preferably 5 MPa or higher, and preferably 50 MPa or lower, more preferably 30 MPa or lower, still more preferably 20 MPa or lower. The cure time is preferably 1 minute or longer, more preferably 2 minutes or longer, still more preferably 5 minutes or longer, and preferably 60 minutes or shorter, more preferably 30 minutes or shorter, still more preferably 20 minutes or shorter.

[0136] The formation of the first resin composition layer in step (I) may be carried out, for example, using a resin sheet. The resin sheet refers to a sheet comprising a support and a first resin composition layer formed on the support. By laminating the resin sheet and the substrate so that the first resin composition layer and the substrate are joined, the first resin composition layer can be formed on the substrate. The first resin composition layer comprised in the resin sheet usually has the same thickness as the first resin composition layer to be formed on the substrate.

[0137] Examples of the support include a film of a plastic material, a metal foil, and a release paper, with a film of a plastic material and a metal foil being preferred.

[0138] When using a film of a plastic material as the support, examples of the plastic material include polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter sometimes abbreviated as "PEN"), polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylics such as polymethyl methacrylate (PMMA), cyclic polyolefin, triacetyl cellulose (TAC), polyethersulfide (PES), polyether ketone, polyimide, etc. Among them, polyethylene terephthalate and polyethylene naphthalate are preferred, and inexpensive polyethylene terephthalate is particularly preferred.

[0139] When using a metal foil as the support, examples of the metal foil include a copper foil and an aluminum foil, with a copper foil being preferred. As the copper foil, a foil made of single metal copper may be used, or a foil made of an alloy of copper and other metals (for example, tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.) may be used.

[0140] The support may be subjected to surface treatments such as mat treatment, corona treatment, and antistatic treatment on the surface that joins the first resin composition layer.

[0141] As the support, a support with a release layer having a release layer on the surface that bonds to the first resin composition layer may be used. Examples of the release agent used for the release layer of the support with a release layer include one or more release agents selected from the group consisting of alkyd-based release agents, polyolefin-based release agents, urethane-based release agents, and silicone-based release agents. As the support with a release layer, a commercially available product may be used. For example, “PET501010”, “SK-1”, “AL-5”, “AL-7” manufactured by Lintec Corporation, which are PET films having a release layer mainly composed of a silicone-based release agent or an alkyd resin-based release agent; “Lumirror T60” manufactured by Toray Industries, Inc.; “Purex” manufactured by Teijin Limited; “Unipile” manufactured by Unitika Ltd., etc. may be mentioned.

[0142] The thickness of the support is not particularly limited, but is preferably 1 μm or more, more preferably 5 μm or more, still more preferably 10 μm or more, and preferably 75 μm or less, more preferably 60 μm or less, still more preferably 50 μm or less. When using a support with a release layer, it is preferable that the total thickness of the support with a release layer is within the above range.

[0143] The resin sheet may be provided with any member as necessary. For example, the resin sheet may be provided with a protective film that protects the first resin composition layer. The protective film is usually provided on the surface that is not bonded to the support of the first resin composition layer (that is, the surface opposite to the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. When the protective film is provided, adhesion of dust and scratches to the surface of the first resin composition layer can be suppressed. When the resin sheet has a protective film, the resin sheet is usually laminated with the substrate after peeling off the protective film.

[0144] The resin sheet may be manufactured, for example, by applying a liquid first resin composition onto a support and, if necessary, further drying it to form a first resin composition layer. Alternatively, the resin sheet may be manufactured, for example, by mixing a solvent and the first resin composition to prepare a liquid first resin composition, applying this onto a support, and further drying it to form a first resin composition layer. As the solvent, the same solvents as the (H) solvents described as components of the first resin composition may be used.

[0145] Coating can be performed using an appropriate coating device such as a die coater. Also, drying may be carried out by methods such as heating and hot air blowing. The drying conditions are not particularly limited, but it is dried so that the solvent content in the first resin composition layer is usually 10% by mass or less, preferably 5% by mass or less. Although it also varies depending on the boiling point of the solvent in the resin composition, for example, when applying a liquid first resin composition containing 30% to 60% by mass of the solvent, the first resin composition layer can be formed by drying at 50°C to 150°C for 3 minutes to 10 minutes.

[0146] Examples of the method for laminating the resin sheet and the base material include a method of thermocompression bonding the resin sheet to the base material from the support side. Examples of the member for thermocompression bonding the resin sheet to the base material (hereinafter also referred to as the "thermocompression bonding member") include a heated metal plate (such as a SUS mirror plate) or a metal roll (such as a SUS roll). Note that it is preferable to press through an elastic material such as heat-resistant rubber so that the resin sheet sufficiently follows the surface unevenness of the base material instead of directly pressing the thermocompression bonding member against the resin sheet.

[0147] The lamination of the base material and the resin sheet may be carried out by the vacuum lamination method. In the vacuum lamination method, the lamination conditions can be as follows. The heat-sealing temperature is preferably in the range of 60°C to 160°C, more preferably in the range of 80°C to 140°C. The heat-sealing pressure is preferably in the range of 0.098 MPa to 1.77 MPa, more preferably in the range of 0.29 MPa to 1.47 MPa. The heat-sealing time is preferably in the range of 20 seconds to 400 seconds, more preferably in the range of 30 seconds to 300 seconds. The lamination is preferably carried out under reduced pressure conditions of a pressure of 26.7 hPa or less.

[0148] The lamination can be carried out by a commercially available vacuum laminator. Examples of commercially available vacuum laminators include a vacuum pressure type laminator manufactured by Meiki Seisakusho Co., Ltd., a vacuum applicator manufactured by Nichioh Materials Co., Ltd., a batch type vacuum pressure laminator, and the like.

[0149] After the lamination, under normal pressure (atmospheric pressure), for example, the formed first resin composition layer may be smoothed by pressing the heat-sealing member from the support side. The pressing conditions for the smoothing treatment can be the same as the heat-sealing conditions for the above lamination. The smoothing treatment can be carried out by a commercially available laminator. Note that the lamination and the smoothing treatment may be carried out continuously using the above commercially available vacuum laminator.

[0150] When the first resin composition layer is formed on the base material using the resin sheet in step (I), the support of the resin sheet is removed after the formation of the first resin composition layer. The support may be removed between step (I) and step (II), or may be removed after step (II).

[0151] The formation of the first resin composition layer in step (I) may be carried out, for example, by a method including the application of the first resin composition. To give a specific example, a liquid first resin composition may be applied onto a substrate and further dried as necessary to form the first resin composition layer. Further, to give another specific example, a solvent and the first resin composition may be mixed to prepare a liquid first resin composition, which is applied onto a substrate and further dried to form the first resin composition layer. As the solvent, those similar to the solvent (H) described as a component of the first resin composition may be used. Also, the application and drying may be carried out under the same conditions as the application and drying described in the method for manufacturing a resin sheet. At this time, the application of the liquid first resin composition is preferably carried out by a method other than the spin coating method from the viewpoint of forming a first cured layer suitable for polishing. For example, it is preferable to use the die coating method.

[0152] (Explanation of the thickness of the first resin composition) The thickness of the first resin composition layer formed in step (I) is preferably 50 μm or more, more preferably 100 μm or more, and still more preferably 150 μm or more. When the thickness of the first resin composition layer is at least the above lower limit value, the first cured layer before polishing can be made thicker, so that a first cured layer having a sufficient thickness can be obtained after polishing. The upper limit of the thickness of the first resin composition layer may be set according to the structure of the circuit board to be manufactured and can be, for example, 500 μm or less, 400 μm or less, 300 μm or less, etc.

[0153] (Step (II) of curing the first resin composition layer) The method for manufacturing a circuit board according to an embodiment of the present invention includes, after step (I), step (II) of curing the first resin composition layer. By curing the first resin composition layer, a first cured layer is formed.

[0154] The curing of the first resin composition layer can be carried out by an appropriate method according to the type of the (B) first curable resin. For example, when the (B) first curable resin contains a thermosetting resin, the first resin composition layer may be cured by heating. Also, for example, when the (B) first curable resin contains a photocurable resin, the first resin composition layer may be cured by light irradiation. In a preferred embodiment, since the (B) first curable resin contains a thermosetting resin, in step (II), the first resin composition layer is cured by heating.

[0155] In one example, the specific curing temperature of the first resin composition layer is preferably 120°C to 240°C, more preferably 150°C to 220°C, and even more preferably 170°C to 210°C. Also, in one example, the curing time is preferably 5 minutes to 120 minutes, more preferably 10 minutes to 100 minutes, and even more preferably 15 minutes to 100 minutes.

[0156] Step (II) may include preheating the first resin composition layer at a temperature lower than the curing temperature before curing the first resin composition layer. The preheating is carried out, for example, usually at a temperature of 50°C to 150°C, preferably 60°C to 140°C, more preferably 70°C to 130°C, and the first resin composition layer is heated under the condition of usually 5 minutes or more, preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes, and even more preferably 15 minutes to 100 minutes of treatment time.

[0157] The formed first cured layer includes a first cured product as the cured product of the first resin composition, and preferably includes only the first cured product. The first cured layer usually has an elastic modulus G1 in the same range as the elastic modulus G1 of the above-described first cured product. When the first cured layer has such an elastic modulus G1, warping of the circuit board and intermediate products during its manufacture can be effectively suppressed, and the manufacture of the circuit board can be carried out smoothly.

[0158] Also, the first cured layer usually has a dielectric loss tangent in the same range as the dielectric loss tangent of the above-described first cured product. Further, the first cured layer usually has the same thickness as the first resin composition layer before curing.

[0159] <Step (III): Polishing the first cured layer> The method for manufacturing a circuit board according to an embodiment of the present invention includes, after step (II), a step (III) of polishing the surface of the first cured layer. When the first cured layer is formed on a substrate, usually, the surface of the first cured layer on the side opposite to the substrate is polished. By polishing, a smooth polished surface is formed on the surface of the first cured layer. Also, by polishing, the thickness of the first cured layer decreases. Further, as described above, recesses can be formed in the polished surface by polishing.

[0160] The polished surface formed on the surface of the first cured layer by polishing usually has a small surface roughness. For example, the arithmetic mean roughness of the polished surface of the first cured layer is preferably 500 nm or less, more preferably 300 nm or less, and particularly preferably 100 nm or less. The lower limit is not particularly limited and can be, for example, 10 nm or more, 20 nm or more, 50 nm or more, etc. However, this arithmetic mean roughness indicates the value in an area without recesses. The arithmetic mean roughness can be measured using a non-contact surface roughness meter ("WYKO NT3300" manufactured by Veeco Instruments Inc.) in VSI mode using a 50x lens.

[0161] Recesses caused by the (A) first inorganic filler contained in the first resin composition are usually formed on the polished surface of the first cured layer. The size of these recesses generally corresponds to the size of the (A) first inorganic filler. For example, the opening diameter of a recess formed by the detachment of one particle of the (A) first inorganic filler can be the same as or close to the diameter of one such particle. Also, for example, the opening diameter of a recess formed by the opening of a void formed within a particle of the (A) first inorganic filler by polishing can be a value smaller than the diameter of one such particle. Further, for example, the opening diameter of a recess formed by a plurality of particles of the (A) first inorganic filler detaching as a lump can be a value larger than the diameter of one such particle. The specific opening diameter of the recesses can vary depending on the particle size, amount, degree of dispersion, and size of the voids of the (A) first inorganic filler. In one example, the lower limit of the opening diameter of the recesses can be, for example, 1 μm or more, 2 μm or more, 3 μm or more, etc. Also, the upper limit can be, for example, 50 μm or less, 40 μm or less, 30 μm or less, etc.

[0162] By polishing, the thickness of the first cured layer decreases. At this time, the amount of decrease in thickness is the thickness T1 of the first cured layer before polishing b and the thickness T1 of the first cured layer after polishing a and the difference T1 b -T1 a is represented by. The amount of decrease in thickness T1 of the first cured layer by polishing b -T1 a is usually 10 μm or more, preferably 20 μm or more, and more preferably 30 μm or more. When polishing is performed to such an extent that the thickness of the first cured layer significantly decreases, (A) there is a tendency that recesses due to the first inorganic filler are likely to be formed. Therefore, from the viewpoint of utilizing the advantage of this embodiment that the problems caused by the recesses can be solved, the amount of decrease in thickness T1 of the first cured layer by polishing b -T1 a is preferably within the above range. The upper limit of the amount of decrease in thickness T1 of the first cured layer by polishing b -T1 a is a value smaller than the thickness T1 of the first cured layer before polishing b and can be, for example, 300 μm or less, 200 μm or less, 100 μm or less, etc.

[0163] The thickness T1 of the first cured layer after polishing a can be set according to the design of the circuit board. The range of the specific thickness T1 of the first cured layer after polishing a is, in one example, preferably 20 μm or more, more preferably 50 μm or more, still more preferably 100 μm or more, still more preferably 120 μm or more, and preferably 400 μm or less, more preferably 300 μm or less, still more preferably 200 μm or less.

[0164] Examples of the polishing method of the first cured layer include a chemical mechanical polishing method using a chemical mechanical polishing apparatus; mechanical polishing methods such as belt polishing, buff polishing, ceramic polishing, grinding using a surface grinder, and surface grinding by rotating a grinding wheel; and the like. Depending on the state of the target polished surface, abrasive grains of various meshes may be used.

[0165] <Step (IV) of forming the second resin composition layer> In the manufacturing method of a circuit board according to an embodiment of the present invention, after step (III), step (IV) of forming a second resin composition layer on the surface of the polished first cured layer (i.e., the polished surface) with a second resin composition containing a curable resin is included. Hereinafter, the curable resin contained in the second resin composition may be referred to as "(b) second curable resin". According to step (IV), a second resin composition layer containing the second resin composition is formed. Usually, this second resin composition layer contains only the second resin composition.

[0166] (Explanation of (a) second inorganic filler) The second resin composition either does not contain an inorganic filler or contains one. Hereinafter, the inorganic filler contained in the second resin composition may be referred to as "(a) second inorganic filler". When the second resin composition contains (a) second inorganic filler as component (a), the (a) second inorganic filler is usually contained in the second resin composition in a particulate state and can be contained in the second cured layer while maintaining the particulate state.

[0167] When the second resin composition contains (a) second inorganic filler, the range of the 99% particle size of the (a) second inorganic filler is usually 2 μm or less, preferably 1.5 μm or less, more preferably 1.0 μm or less, and still more preferably 0.5 μm or less. The lower limit can be, for example, 0.01 μm or more, 0.1 μm or more, etc. The 99% particle size of the inorganic filler such as (a) second inorganic filler represents the particle size at which the cumulative volume from the small-diameter side in the volume-based particle size distribution of the inorganic filler becomes 99%, as described above. When the second resin composition does not contain (a) second inorganic filler or contains (a) second inorganic filler having a 99% particle size within the above range, the formation of recesses on the polished surface of the cured product layer (i.e., the polished surface of the second cured layer) can be suppressed.

[0168] The 99% particle size of the (a) second inorganic filler can be measured in the same manner as the 99% particle size of the (A) first inorganic filler.

[0169] When the second resin composition contains (a) a second inorganic filler, the average particle diameter D2 of (a) the second inorganic filler is preferably smaller than the average particle diameter D1 of (A) the first inorganic filler contained in the first resin composition. In this case, the formation of recessed portions on the polished surface of the cured product layer (i.e., the polished surface of the second cured layer) can be effectively suppressed.

[0170] The range of the ratio D1 / D2 of the average particle diameter D1 of (A) the first inorganic filler to the average particle diameter D2 of (a) the second inorganic filler is preferably 2 or more, more preferably 3 or more, still more preferably 5 or more, and preferably 500 or less, more preferably 300 or less, still more preferably 100 or less. When the ratio D1 / D2 of the average particle diameters is within the above range, the formation of recessed portions on the polished surface of the cured product layer can be effectively suppressed.

[0171] The range of the average particle diameter D2 of (a) the second inorganic filler is preferably 0.01 μm or more, more preferably 0.05 μm or more, still more preferably 0.1 μm or more, and preferably 2 μm or less, more preferably 1 μm or less, still more preferably 0.5 μm or less. When the average particle diameter D2 of (a) the second inorganic filler is within the above range, the formation of recessed portions on the polished surface of the cured product layer can be effectively suppressed.

[0172] The average particle diameter D2 of (a) the second inorganic filler can be measured in the same manner as the average particle diameter D1 of (A) the first inorganic filler.

[0173] The range of the specific surface area of (a) the second inorganic filler may be the same as the range of the specific surface area of (A) the first inorganic filler, but usually, the specific surface area of (a) the second inorganic filler is larger than the specific surface area of (A) the first inorganic filler. For example, the difference between the specific surface area of (a) the second inorganic filler and the specific surface area of (A) the first inorganic filler is preferably 0.1 m 2 / g or more, more preferably 1 m 2 / g or more, still more preferably 2 m 2 / g or more, particularly preferably 4 m 2 / g or more. The upper limit is, for example, 80 m 2 / g or less, 50 m 2 / g or less, 20 m 2 / g or less, 10 m2 It may be, for example, less than / g. (a) The specific surface area of the second inorganic filler can be measured in the same manner as (A) the specific surface area of the first inorganic filler.

[0174] (a) As the second inorganic filler, in addition to having a particle size within the above-described range, the same one as (A) the first inorganic filler may be used. Therefore, as the material of (a) the second inorganic filler, the same one as that described as the material of (A) the first inorganic filler may be used. Further, (a) the second inorganic filler may be treated with a surface treatment agent in the same manner as (A) the first inorganic filler. At this time, the type of the surface treatment agent for treating (a) the second inorganic filler and the degree of the surface treatment may be the same as the type of the surface treatment agent for treating (A) the first inorganic filler and the degree of the surface treatment.

[0175] The amount (mass%) of (a) the second inorganic filler in the second resin composition is preferably less than the amount (mass%) of (A) the first inorganic filler in the first resin composition. The specific range of the amount of (a) the second inorganic filler in the second resin composition is usually 0 mass% or more than 0 mass% with respect to 100 mass% of the non-volatile components in the second resin composition, and may be, for example, 30 mass% or more, 40 mass% or more, etc. The upper limit is preferably 90 mass% or less, more preferably 80 mass% or less, still more preferably 70 mass% or less, and particularly preferably 60 mass% or less. When the amount of (a) the second inorganic filler is within the above range, the formation of recessed portions on the polished surface of the cured product layer can be effectively suppressed.

[0176] ((Description of (b) the second curable resin)) (b) The second curable resin as the component (b) contained in the second resin composition is a curable resin, and the same one as (B) the first curable resin can be used. Therefore, (b) the second curable resin may be a thermosetting resin, a photocurable resin, or a combination thereof. Among them, (b) the second curable resin preferably contains a thermosetting resin, and more preferably contains only a thermosetting resin.

[0177] (b) Examples of the thermosetting resin that can be used as the second curable resin include the same ones as those described for the thermosetting resin that can be used as the first curable resin (B). Among them, (b) the second curable resin preferably contains an epoxy resin. In particular, when both (B) the first curable resin and (b) the second curable resin contain an epoxy resin, the affinity between the first cured layer and the second cured layer can be improved, and the adhesion between these two layers can be enhanced, so that a cured product layer with excellent mechanical strength can be obtained.

[0178] As the epoxy resin contained in the (b) second curable resin, those described as the epoxy resin contained in the (B) first curable resin may be used. The range of the amount (mass%) of the epoxy resin in the second resin composition may be the same as the range of the amount of the epoxy resin in the first resin composition, but the specific amount is preferably adjusted so that a second cured layer having desired properties can be obtained.

[0179] The range of the amount of the epoxy resin in the second resin composition is preferably 1% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, and preferably 60% by mass or less, more preferably 50% by mass or less, still more preferably 40% by mass or less, based on 100% by mass of the non-volatile components in the second resin composition.

[0180] The range of the amount of the epoxy resin in the second resin composition is preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass or more, and preferably 70% by mass or less, more preferably 60% by mass or less, still more preferably 50% by mass or less, based on 100% by mass of the resin components in the second resin composition. The "resin components" in the second resin composition refers to the components excluding the inorganic filler among the non-volatile components contained in the second resin composition, unless otherwise specified.

[0181] The second resin composition preferably contains a curing agent in combination with an epoxy resin. (b) As the curing agent contained in the second curable resin, those described as the curing agent contained in the (B) first curable resin may be used. The range of the amount (mass%) of the curing agent in the second resin composition may be the same as the range of the amount of the curing agent in the first resin composition, but the specific amount is preferably adjusted so that a second cured layer having desired properties can be obtained.

[0182] The range of the amount of the curing agent in the second resin composition is preferably 1% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, and preferably 80% by mass or less, more preferably 70% by mass or less, still more preferably 60% by mass or less, based on 100% by mass of the non-volatile components in the second resin composition.

[0183] The range of the amount of the curing agent in the second resin composition is preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass or more, and preferably 80% by mass or less, more preferably 70% by mass or less, still more preferably 60% by mass or less, based on 100% by mass of the resin components in the second resin composition.

[0184] When the second resin composition contains a combination of an epoxy resin and a curing agent, the range of the active hydrogen group number of the curing agent with respect to the epoxy group number 1 of the epoxy resin is preferably 0.1 or more, more preferably 0.3 or more, still more preferably 0.5 or more, and preferably 3.0 or less, more preferably 2.5 or less, particularly preferably 2.0 or less. The "epoxy group number of the epoxy resin" in the second resin composition represents the total value obtained by summing up the values obtained by dividing the mass of the non-volatile components of the epoxy resin present in the second resin composition by the epoxy equivalent. Also, the "active hydrogen group number of the curing agent" in the second resin composition represents the total value obtained by summing up the values obtained by dividing the mass of the non-volatile components of the curing agent present in the second resin composition by the active hydrogen group equivalent.

[0185] The range of the amount (mass %) of the (b) second curable resin in the second resin composition may be the same as the range of the amount of the (B) first curable resin in the first resin composition, but the specific amount is preferably adjusted so that a second cured layer having desired properties can be obtained.

[0186] The range of the amount of the (b) second curable resin in the second resin composition is preferably 10 mass % or more, more preferably 20 mass % or more, still more preferably 30 mass % or more, and preferably 100 mass % or less, more preferably 95 mass % or less, still more preferably 90 mass % or less, based on 100 mass % of the nonvolatile components in the second resin composition.

[0187] The range of the amount of the (b) second curable resin in the second resin composition is preferably 50 mass % or more, more preferably 60 mass % or more, still more preferably 70 mass % or more, and preferably 100 mass % or less, more preferably 95 mass % or less, still more preferably 90 mass % or less, based on 100 mass % of the resin components in the second resin composition.

[0188] The range of the total amount of the (a) second inorganic filler and the (b) second curable resin in the second resin composition is preferably 70 mass % or more, more preferably 80 mass % or more, still more preferably 85 mass % or more, based on 100 mass % of the nonvolatile components in the first resin composition. The upper limit is usually 100 mass % or less, and may be, for example, 98 mass % or less or 96 mass % or less.

[0189] ((c) Explanation of the polymer resin) The second resin composition may contain, as an optional component, (c) a polymer resin. The (c) polymer resin usually has thermoplasticity and is contained in the second resin composition in a state compatible with the resin components other than the (c) polymer resin. The (c) polymer resin as the (c) component does not include those corresponding to the above-mentioned (a) to (b) components. As the (c) polymer resin contained in the second resin composition, the same one as the (C) polymer resin that can be contained in the first resin composition can be used.

[0190] The range of the amount (mass %) of the (c) polymer resin in the second resin composition may be the same as the range of the amount of the (C) polymer resin in the first resin composition, but the specific amount is preferably adjusted so that a second cured layer having desired properties can be obtained.

[0191] The range of the amount of the (c) polymer resin in the second resin composition is preferably 0.1 mass % or more, more preferably 1 mass % or more, still more preferably 2 mass % or more, and preferably 30 mass % or less, more preferably 20 mass % or less, still more preferably 15 mass % or less, based on 100 mass % of the non-volatile components in the second resin composition.

[0192] The range of the amount of the (c) polymer resin in the second resin composition is preferably 1 mass % or more, more preferably 5 mass % or more, still more preferably 10 mass % or more, and preferably 40 mass % or less, more preferably 30 mass % or less, still more preferably 20 mass % or less, based on 100 mass % of the resin components in the second resin composition.

[0193] ((Description of the (d) curing accelerator)) The second resin composition may contain, as an optional component, a (d) curing accelerator. Since the (d) curing accelerator can act as a catalyst for the reaction of the (b) second curable resin, it can accelerate the curing of the second resin composition. The (d) curing accelerator as the (d) component does not include those corresponding to the above-described (a) to (c) components. As the (d) curing accelerator contained in the second resin composition, the same one as the (D) curing accelerator that can be contained in the first resin composition can be used.

[0194] The range of the amount (mass %) of the (d) curing accelerator in the second resin composition may be the same as the range of the amount of the (D) curing accelerator in the first resin composition, but the specific amount is preferably adjusted so that a second cured layer having desired properties can be obtained.

[0195] The range of the amount of (d) the curing accelerator in the second resin composition is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, still more preferably 0.05% by mass or more, and preferably 2% by mass or less, more preferably 1% by mass or less, still more preferably 0.5% by mass or less, based on 100% by mass of the nonvolatile components in the second resin composition.

[0196] The range of the amount of (d) the curing accelerator in the second resin composition is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, still more preferably 0.1% by mass or more, and preferably 5% by mass or less, more preferably 2% by mass or less, still more preferably 1% by mass or less, based on 100% by mass of the resin components in the second resin composition.

[0197] ((Explanation of the adhesion promoter (e))) The second resin composition may contain (e) an adhesion promoter as an optional component. According to the (e) adhesion promoter, the adhesion strength between the cured product layer and the layer in contact with the cured product layer can be increased. The (e) adhesion promoter as the (e) component does not include those corresponding to the above-described (a) to (d) components. As the (e) adhesion promoter contained in the second resin composition, the same ones as the (E) adhesion promoter that can be contained in the first resin composition can be used.

[0198] The range of the amount (mass%) of the (e) adhesion promoter in the second resin composition may be the same as the range of the amount of the (E) adhesion promoter in the first resin composition, but the specific amount is preferably adjusted so that a second cured layer having desired properties can be obtained.

[0199] ((Explanation of the flame retardant (f))) The second resin composition may contain (f) a flame retardant as an optional component. According to the (f) flame retardant, the flame retardancy of the cured product layer can be improved. The (f) flame retardant as the (f) component does not include those corresponding to the (a) to (e) components. As the (f) flame retardant contained in the second resin composition, the same ones as the (F) flame retardant that can be contained in the first resin composition can be used.

[0200] The range of the amount (mass %) of the flame retardant (f) in the second resin composition may be the same as the range of the amount of the flame retardant (F) in the first resin composition, but the specific amount thereof is preferably adjusted so that a second cured layer having desired properties can be obtained.

[0201] ((Description of optional additive (g)) The second resin composition may further contain (g) an optional additive as an optional component. The (g) optional additive as the component (g) does not include those corresponding to the components (a) to (f) described above. As the (g) optional additive contained in the second resin composition, the same ones as the (G) optional additive that can be contained in the first resin composition can be used.

[0202] ((Description of solvent (h)) The second resin composition may further contain (h) a solvent as an optional volatile component in combination with the non-volatile components such as the components (a) to (g) described above. As the (h) solvent contained in the second resin composition, the same ones as the (H) solvent that can be contained in the first resin composition can be used.

[0203] The amount of the (h) solvent in the second resin composition for forming the second resin composition layer is preferably small. The amount of the (h) solvent in the second resin composition is preferably 10% by mass or less, more preferably 5% by mass or less, still more preferably 4% by mass or less, still more preferably 3% by mass or less, still more preferably 2% by mass or less, based on 100% by mass of the total amount of the first resin composition. The lower limit may be 0% by mass or may be 0.0001% by mass or more.

[0204] (Description of properties of the second resin composition and its cured product) The second resin composition forms a cured product by being cured. Hereinafter, the cured product of the second resin composition may be referred to as the "second cured product". A second cured layer is formed by this second cured product. During curing, usually heat is applied to the second resin composition, so among the components contained in the second resin composition, the (h) solvent as a volatile component can be volatilized by the heat during curing. Therefore, the second cured product may contain a non-volatile component of the second resin composition or a reaction product thereof.

[0205] The second cured product usually has an elastic modulus G2 that is smaller than the elastic modulus G1 of the first cured product. The range of the ratio G1 / G2 of the elastic modulus G1 of the first cured product to the elastic modulus G2 of the second cured product is preferably 1.1 or more, more preferably 1.3 or more, still more preferably 1.5 or more, and preferably 10 or less, more preferably 6 or less, still more preferably 4 or less. When the ratio G1 / G2 of the elastic moduli is within the above range, warping of the circuit board and intermediate products during its manufacture can be effectively suppressed, and the manufacture of the circuit board can be carried out smoothly.

[0206] The range of the elastic modulus G2 of the second cured product is preferably less than 10 GPa, and may be 9 GPa or less. The lower limit is preferably 1 GPa or more, more preferably 2 GPa or more, still more preferably 3 GPa or more. When the elastic modulus G2 of the second cured product is within the above range, warping of the circuit board and intermediate products during its manufacture can be effectively suppressed, and the manufacture of the circuit board can be carried out smoothly. Also, usually, formation of polishing marks on the second cured layer can be suppressed, and resin clogging of the polishing apparatus can be suppressed, so that polishing of the second cured layer can be carried out smoothly.

[0207] The elastic modulus G2 of the second cured product can be measured by the same method as the elastic modulus G1 of the first cured product. When the sample is the second resin composition before curing, the second resin composition may be cured under curing conditions of 180 °C for 90 minutes to obtain a second cured product, and the elastic modulus of the second cured product may be measured.

[0208] The elastic modulus G2 of the second cured product can be adjusted, for example, by the composition of the second resin composition (for example, (a) the type and amount of the second inorganic filler, (b) the type and amount of the second curable resin, and (c) the type and amount of any component such as a polymer resin, etc.).

[0209] The second cured product preferably has a small dielectric tangent. The range of the dielectric tangent of the second cured product is preferably 0.020 or less, more preferably 0.010 or less, still more preferably 0.005 or less. The lower limit has no particular limitation and can be, for example, 0.0001 or more. The dielectric tangent of the second cured product can be measured by the same method as that of the first cured product. When the sample is the second resin composition before curing, the second resin composition may be cured under the curing conditions of 180°C for 90 minutes to obtain a second cured product, and the dielectric tangent of the second cured product may be measured.

[0210] (Description of the method for manufacturing the second resin composition) The second resin composition can be produced, similarly to the first resin composition, by mixing the components that can be contained in the second resin composition.

[0211] (Description of the method for forming the second resin composition layer) In step (IV), a second resin composition layer is formed on the polished surface of the first cured layer. As the method for forming the second resin composition layer, the same method as the method for forming the first resin composition layer may be employed.

[0212] Therefore, the formation of the second resin composition layer in step (IV) may be carried out, for example, by compression molding (compression molding method). The molding conditions may be the same as those for forming the first resin composition layer in step (I).

[0213] In addition, the formation of the second resin composition layer in step (IV) may be carried out, for example, using a resin sheet including a support and the second resin composition layer formed on the support. When using a resin sheet, the second resin composition layer can be formed on the polished surface of the first cured layer by laminating the resin sheet and the first cured layer so that the second resin composition layer and the polished surface of the first cured layer are joined. The resin sheet used for forming the second resin composition layer may be the same as the resin sheet used for forming the first resin composition layer in step (I), except that the second resin composition layer is provided instead of the first resin composition layer. Further, the resin sheet used for forming the second resin composition layer can be manufactured by the same method as the manufacturing method of the first resin sheet, except that the second resin composition is used instead of the first resin composition. The lamination method and lamination conditions may adopt the same lamination method and lamination conditions as those for forming the first resin composition layer in step (I).

[0214] Similar to the method for forming the first resin composition layer, after lamination, a smoothing treatment of the formed second resin composition layer may be performed, for example, by pressing a heat-sealing member from the support side under normal pressure (atmospheric pressure). When the second resin composition layer is formed on the first cured layer using a resin sheet in step (IV), the support of the resin sheet is removed after the formation of the second resin composition layer. The support may be removed between step (IV) and step (V), or may be removed after step (V).

[0215] Furthermore, the formation of the second resin composition layer in step (IV) may be carried out, for example, by a method including the application of the second resin composition. The method for forming the second resin composition layer including this application may be carried out by the same method as the formation method including the application for forming the first resin composition layer. At this time, the application of the liquid second resin composition is preferably carried out by a method other than the spin coating method from the viewpoint of forming a second cured layer suitable for polishing, and for example, it is preferable to use the die coating method.

[0216] (Explanation of the thickness of the second resin composition) The thickness of the second resin composition layer formed in step (IV) is preferably 20 μm or more, more preferably 30 μm or more, and still more preferably 50 μm or more. Generally, the thickness of the second cured layer decreases by polishing, but when the thickness of the second resin composition layer before polishing is equal to or greater than the above lower limit value, a second cured layer having an appropriate thickness can be obtained after polishing. The upper limit of the thickness of the second resin composition layer is preferably 200 μm or less, more preferably 150 μm or less, and still more preferably 100 μm or less, from the viewpoint of suppressing warping of the intermediate product during the manufacture of the circuit board.

[0217] <Step (V) of curing the second resin composition layer> The method for manufacturing a circuit board according to an embodiment of the present invention includes step (V) of curing the second resin composition layer after step (IV). By curing the second resin composition layer, a second cured layer is formed.

[0218] The curing of the second resin composition layer can be performed by an appropriate method according to the type of (b) the second curable resin. For example, when (b) the second curable resin contains a thermosetting resin, the second resin composition layer may be cured by heating. Further, for example, when (b) the second curable resin contains a photocurable resin, the second resin composition layer may be cured by light irradiation. In a preferred embodiment, since (b) the second curable resin contains a thermosetting resin, step (V) cures the second resin composition layer by heating. The range of curing conditions such as the curing temperature and curing time of the second resin composition layer may be the same as the range of curing conditions of the first resin composition layer in step (II).

[0219] Step (V) may include preheating the second resin composition layer at a temperature lower than the curing temperature before curing the second resin composition layer. The range of the preheating conditions of the second resin composition layer may be the same as the range of the preheating conditions of the first resin composition layer.

[0220] The formed second cured layer includes a second cured product as a cured product of the second resin composition, and preferably includes only the second cured product. The second cured layer usually has an elastic modulus G2 in the same range as the elastic modulus G2 of the above-described second cured product. The elastic modulus G2 of this second cured layer preferably has a value such that the ratio G1 / G2 of the elastic moduli is in the above-described range. When the second cured layer has such an elastic modulus G2, warping of the circuit board and intermediate products during its manufacture can be effectively suppressed, and the manufacture of the circuit board can be carried out smoothly.

[0221] Also, the second cured layer usually has a dielectric loss tangent in the same range as the dielectric loss tangent of the above-described second cured product. Further, the second cured layer usually has the same thickness as the second resin composition layer before curing.

[0222] <Step (VI) of polishing the second cured layer> The method for manufacturing a circuit board according to an embodiment of the present invention includes, after step (V), a step (VI) of polishing the surface of the second cured layer on the side opposite to the first cured layer. By polishing, a smooth polished surface is obtained as the surface of the polished second cured layer. As the polishing method of the second cured layer, the same method as the polishing method of the first cured layer may be employed.

[0223] By polishing, the thickness of the second cured layer decreases. At this time, the amount of decrease in thickness is the thickness T2 of the second cured layer before polishing b and the thickness T2 of the second cured layer after polishing a and the difference T2 b -T2 a represented by. The amount of decrease in thickness T2 b -T2 a of the second cured layer due to polishing is usually 10 μm or more, preferably 20 μm or more, more preferably 30 μm or more. The upper limit is a value smaller than the thickness T2 b of the second cured layer before polishing, and can be set so that a second cured layer with a desired thickness is obtained after polishing.

[0224] Usually, the thickness T2 a of the second cured layer after polishing is the thickness (thickness of the first cured layer after polishing) T1 ais smaller. Generally, the first cured layer containing the first inorganic filler is excellent in mechanical properties such as the linear thermal expansion coefficient and mechanical strength; and electrical properties such as the dielectric tangent. Therefore, when the first cured layer having such excellent properties is thick and the second cured layer is thin, the properties of the cured product layer formed by the combination of the first cured layer and the second cured layer can be made particularly good. The thickness T2 of the second cured layer after polishing in step (VI) a and the thickness T1 of the first cured layer a The ratio T2 a / T1 a is preferably 0.9 or less, more preferably 0.5 or less, and still more preferably 0.2 or less. The lower limit can be, for example, 0.01 or more, 0.05 or more, 0.1 or more, etc. Also, the thickness ratio T2 a / T1 a When it is within the above range, usually, the warpage of the circuit board can be effectively suppressed.

[0225] From the viewpoint of particularly effectively suppressing the warpage of the circuit board, the product of the elastic modulus G1 of the first cured layer and the thickness T1 of the first cured layer after polishing a and the product of the elastic modulus G2 of the second cured layer and the thickness T2 of the second cured layer after polishing a The ratio "(G1 × T1 a ) / (G2 × T2 a )" is preferably within a specific range. The specific range of the ratio "(G1 × T1 a ) / (G2 × T2 a )" is preferably 5 or more, more preferably 8 or more, and still more preferably 10 or more. The upper limit is preferably 100 or less, and may be 80 or less or 50 or less.

[0226] From the viewpoint of smoothly performing the polishing of the second cured layer, it is preferable that not only the warpage of the circuit board obtained after polishing the second cured layer but also the warpage of the intermediate product obtained before polishing the second cured layer are suppressed. From the viewpoint of suppressing the warpage of both the circuit board and its intermediate product in this way, the ratio G1 / G2 of the elastic modulus G1 of the first cured layer and the elastic modulus G2 of the second cured product, and the thickness T2 of the second cured layer after polishing a and the thickness T2 of the second cured layer before polishing b The ratio T2 a / T2b The parameter “(G1 / G2)×(T2 a / T2 b )” represented by the product with is preferably within a specific range. The specific range of the parameter “(G1 / G2)×(T2 a / T2 b )” is preferably 1.2 or less, more preferably 1.1 or less, still more preferably 1.0 or less, and particularly preferably 0.9 or less. The lower limit is preferably 0.1 or more, and may be 0.2 or more or 0.3 or more.

[0227] The thickness T2 of the second cured layer after polishing a In one example, the range is preferably 5 μm or more, more preferably 10 μm or more, still more preferably 15 μm or more, and preferably 300 μm or less, more preferably 200 μm or less, still more preferably 100 μm or less.

[0228] In the manufacturing method according to this embodiment, a cured product layer can be formed by combining the first cured layer and the second cured layer after polishing. And the outermost surface of this cured product layer is formed by the surface of the second cured layer on the side opposite to the first cured layer. Since the surface of the second cured layer is polished in step (VI), the surface can form a polished surface of the cured product layer. Also, since the recessed portions on the polished surface of the first cured layer are filled by the second cured layer, the recessed portions do not appear on the polished surface of the cured product layer. Therefore, according to the manufacturing method according to this embodiment, a circuit board provided with a cured product layer having a smooth polished surface with the formation of recessed portions suppressed can be obtained. In one example, the number of recessed portions with a diameter of 5 μm or more on the polished surface of the cured product layer is, per 1 cm 2 Preferably, it can be less than 30, more preferably less than 10.

[0229] The polished surface of the cured product layer (that is, the polished surface of the second cured layer) usually has a small surface roughness. For example, the arithmetic mean roughness of the polished surface of the second cured layer is preferably 500 nm or less, more preferably 300 nm or less, and particularly preferably 100 nm or less. The lower limit is not particularly limited and can be, for example, 10 nm or more, 20 nm or more, 50 nm or more, etc.

[0230] The polished surface of the cured material layer (i.e., the polished surface of the second cured layer) preferably has a high hardness. For example, the Vickers hardness of the polished surface of the cured material layer is preferably 10 HV or more, more preferably 20 HV or more, still more preferably 30 HV or more, and preferably 200 HV or less, more preferably 150 HV or less, still more preferably 100 HV or less. When the first cured material has such a large Vickers hardness, the polishing of the second cured layer in step (VI) can be performed smoothly. For example, the formation of polishing marks on the second cured layer can be suppressed, or the resin clogging of the polishing apparatus can be suppressed.

[0231] The Vickers hardness can be measured using a Vickers hardness tester. As the specific measurement method of the Vickers hardness, the method described in (Vickers hardness measurement test) of the examples described later can be adopted. The Vickers hardness of the cured material layer can be adjusted, for example, by the compositions of the first resin composition and the second resin composition.

[0232] The polished surface of the cured layer (i.e., the polished surface of the second cured layer) preferably has high wettability with respect to the photosensitive resin composition. The wettability of the polished surface of the cured layer can be represented, for example, by the contact angle with respect to the photosensitive resin composition. The range of the contact angle is preferably 10° or more, more preferably 15° or more, still more preferably 20° or more, and preferably 90° or less, more preferably 80° or less, still more preferably 70° or less. The photosensitive resin composition may be applied to the polished surface of the cured layer to form a photosensitive resin composition layer. When the polished surface of the cured layer has excellent wettability, the photosensitive resin composition layer can be formed uniformly and smoothly. Therefore, repulsion of the photosensitive resin composition can be suppressed, and formation of dents in the photosensitive resin composition layer can be suppressed. Conventionally, it has sometimes been difficult to adopt a composition having excellent wettability with respect to the photosensitive resin composition for the cured product of the resin composition due to restrictions on electrical and mechanical properties. In contrast, in the present embodiment, while adopting a composition having excellent electrical and mechanical properties for the first cured layer, a composition having excellent wettability can be adopted for the second cured layer. Therefore, it is possible to achieve excellent wettability of the polished surface of the cured layer while improving the electrical and mechanical properties of the entire cured layer. The contact angle can be measured by the droplet method using the θ / 2 method. Specifically, a droplet of 1.0 μL of the photosensitive resin composition is attached to the polished surface, and the contact angle can be measured 2000 ms after the droplet has adhered.

[0233] Normally, the manufactured circuit board can suppress warping. In one example, the amount of warping of the circuit board is preferably less than 4000 μm, more preferably less than 3000 μm, still more preferably less than 2500 μm. The amount of warping of the circuit board can be measured by the method described in the (warping evaluation test) of the examples described later.

[0234] <Any process> The method for manufacturing a circuit board according to the present embodiment may further include an arbitrary process in combination with the above-described steps (I) to (VI).

[0235] The method for manufacturing a circuit board according to this embodiment may include, for example, a step (VII) of forming holes such as via holes and through holes in the cured layer after step (VI). The method for forming the holes can be selected according to factors such as the composition of the first resin composition and the second resin composition used for forming the cured layer. For example, the holes may be formed by a processing method such as drilling, laser processing, or plasma processing, and among them, laser processing is preferable. The dimensions and shape of the holes may be appropriately determined according to the design of the circuit board.

[0236] The method for manufacturing a circuit board according to this embodiment may include, for example, a step (VIII) of performing a roughening treatment on the polished surface of the cured layer. According to the roughening treatment, the polished surface of the cured layer can be roughened. Also, according to the roughening treatment, smears (resin residues) can be removed from the cured layer. Therefore, this roughening treatment may be called "desmear treatment". For example, when holes are formed in step (VII), smears may be formed in the holes, so it is preferable to perform the roughening treatment of step (VIII) after step (VII) to remove the above-mentioned smears.

[0237] The procedure and conditions of the roughening treatment are not particularly limited. For example, a swelling treatment with a swelling liquid, an oxidation treatment with an oxidizing agent, and a neutralization treatment with a neutralizing liquid may be sequentially performed on the cured layer to perform the roughening treatment.

[0238] Examples of the swelling liquid used for the roughening treatment include an alkaline solution and a surfactant solution, and an alkaline solution is preferable. As the alkaline solution, a sodium hydroxide solution and a potassium hydroxide solution are more preferable. Examples of commercially available swelling liquids include "Swelling Dip Security Gun P" and "Swelling Dip Security Gun SBU" manufactured by Atotech Japan Co., Ltd. The swelling treatment with the swelling liquid can be performed, for example, by immersing the cured layer in the swelling liquid at 30°C to 90°C for 1 minute to 20 minutes. From the viewpoint of suppressing the swelling of the resin of the cured layer to an appropriate level, it is preferable to immerse the cured layer in the swelling liquid at 40°C to 80°C for 5 minutes to 15 minutes.

[0239] Examples of the oxidizing agent used for the roughening treatment include an alkaline permanganate solution in which potassium permanganate or sodium permanganate is dissolved in an aqueous solution of sodium hydroxide. The oxidation treatment with an oxidizing agent such as an alkaline permanganate solution is preferably performed by immersing the cured product layer in the oxidizing agent solution heated to 60°C to 100°C for 10 minutes to 30 minutes. The concentration of the permanganate in the alkaline permanganate solution is preferably 5% by mass to 10% by mass. Examples of commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact CP" and "Dosing Solution Security Guard P" manufactured by Atotech Japan Co., Ltd.

[0240] The neutralizing solution used for the roughening treatment is preferably an acidic aqueous solution. Examples of commercially available products include "Reduction Solution Security Guard P" manufactured by Atotech Japan Co., Ltd. The neutralization treatment with the neutralizing solution can be performed by immersing the treated surface subjected to the oxidation treatment with the oxidizing agent in the neutralizing solution at 30°C to 80°C for 5 minutes to 30 minutes. From the viewpoint of workability, a method of immersing the object subjected to the oxidation treatment with the oxidizing agent in the neutralizing solution at 40°C to 70°C for 5 minutes to 20 minutes is preferable.

[0241] The method for manufacturing a circuit board according to this example may include a step (IX) of forming a conductor layer on the polished surface of the cured product layer. When the method for manufacturing a circuit board includes step (VII) or (VIII), the step (IX) of forming the conductor layer is preferably performed after steps (VII) and (VIII).

[0242] The conductor material used for the conductor layer is not particularly limited. In a preferred embodiment, the conductor layer contains one or more metals selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. The conductor layer may be a single-metal layer or an alloy layer. Examples of the alloy layer include layers formed from alloys of two or more metals selected from the above group (for example, nickel-chromium alloys, copper-nickel alloys, and copper-titanium alloys). Among them, from the viewpoints of the versatility, cost, and ease of patterning of forming the conductor layer, a single-metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or an alloy layer of nickel-chromium alloy, copper-nickel alloy, or copper-titanium alloy is preferred, a single-metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or an alloy layer of nickel-chromium alloy is more preferred, and a single-metal layer of copper is even more preferred.

[0243] The conductor layer may have a single-layer structure or may have a multilayer structure including two or more single-metal layers or alloy layers made of different types of metals or alloys. When the conductor layer has a multilayer structure, the layer in contact with the cured product layer is preferably a single-metal layer of chromium, zinc, or titanium, or an alloy layer of nickel-chromium alloy.

[0244] The thickness of the conductor layer depends on the design of the circuit board, but is preferably 3 μm to 35 μm, more preferably 5 μm to 30 μm.

[0245] The conductor layer may be formed by plating. For example, by plating on the polished surface of the cured product layer by a conventionally known technique such as a semi-additive method or a full-additive method, a conductor layer having a desired wiring pattern can be formed. From the viewpoint of manufacturing simplicity, the semi-additive method is preferred. Hereinafter, an example of forming the conductor layer by the semi-additive method is shown.

[0246] First, an electroless plating layer (plating seed layer) is formed on the polished surface of the cured material layer by electroless plating. Next, a mask pattern is formed on the formed electroless plating layer to expose a part of the electroless plating layer corresponding to a desired wiring pattern. After forming an electrolytic plating layer by electrolytic plating on the exposed electroless plating layer, the mask pattern is removed. Then, an unnecessary electroless plating layer is removed by etching, and a conductor layer having a desired wiring pattern can be formed.

[0247] Since the polished surface of the cured material layer is a smooth plane with the formation of recesses suppressed, when the conductor layer has a wiring pattern, it is possible to reduce the minimum line / space ratio of the conductor layer. Unless otherwise specified, "line" represents the wiring width and "space" represents the interval width between wirings. The range of the minimum line / space ratio of the conductor layer is preferably 10 μm / 10 μm or less, more preferably 5 μm / 5 μm or less, still more preferably 3 μm / 3 μm or less, and preferably 0.1 μm / 0.1 μm or more, more preferably 0.5 μm / 0.5 μm or more, still more preferably 1 μm / 1 μm or more. Also, the wiring pitch of the conductor layer is preferably 20 μm or less, more preferably 10 μm or less, still more preferably 6 μm or less, and preferably 0.2 μm or more, more preferably 1 μm or more, still more preferably 2 μm or more. The line / space ratio and the wiring pitch may each be uniform or non-uniform over the entire conductor layer.

[0248] When a conductor layer is formed on the polished surface of the cured material layer, the method for manufacturing a circuit board may include performing an annealing treatment after the formation of the conductor layer. According to the annealing treatment, the adhesion between the cured material layer and the conductor layer can be enhanced. The annealing treatment can be performed, for example, by heating at 150°C to 210°C for 20 minutes to 180 minutes.

[0249] In the method for manufacturing a circuit board, each of the above-described steps may be performed only once or may be repeated two or more times. For example, steps (I) to (IX) may be repeatedly performed to manufacture a circuit board having a multilayer structure such as a multilayer printed wiring board including a plurality of cured material layers and conductor layers.

[0250] <Specific Example of Circuit Board> Examples of the circuit board manufactured by the manufacturing method according to the above-described embodiment include, for example, a printed wiring board and a semiconductor chip package. Examples of the semiconductor chip package include, for example, a Fan-In type package, a Fan-Out type package, and the like. Specifically, for example, FC-CSP, MIS-BGA package, ETS-BGA package, Fan-out type WLP (Wafer Level Package), Fan-in type WLP, Fan-out type PLP (Panel Level Package), and Fan-in type PLP can be mentioned. In these semiconductor chip packages, it is preferable to form a sealing layer or a rewiring formation layer by a cured product layer as a combination of the above-described first cured layer and second cured layer. However, the circuit board is not limited to those exemplified here.

[0251] Hereinafter, a manufacturing method of a semiconductor chip package will be described as a first example of the circuit board. The semiconductor chip package described in this first example includes an inner layer circuit base material, a semiconductor chip mounted on the inner layer circuit base material, and a sealing layer that seals at least a part of the semiconductor chip. In the first example, the sealing layer is formed by a cured product layer.

[0252] The manufacturing method of the circuit board according to the first example includes a step of bonding a semiconductor chip to the inner layer circuit base material. As the bonding conditions between the inner layer circuit base material and the semiconductor chip, any conditions under which the terminal electrode of the semiconductor chip and the circuit wiring of the inner layer circuit base material can be conductively connected can be adopted. For example, the conditions used in flip chip mounting of the semiconductor chip may be adopted.

[0253] As a bonding method, for example, a method of pressing a semiconductor chip onto an inner layer circuit base material can be mentioned. As the pressing conditions, the pressing temperature is usually in the range of 120°C to 240°C (preferably in the range of 130°C to 200°C, more preferably in the range of 140°C to 180°C), and the pressing time is usually in the range of 1 second to 60 seconds (preferably 5 seconds to 30 seconds). Also, as a bonding method, for example, a method of placing a semiconductor chip on an inner layer circuit base material and performing reflow bonding can be mentioned. The reflow conditions may be in the range of 120°C to 300°C. Further, the method for manufacturing a circuit board according to the first example may include filling the gap between the semiconductor chip and the inner layer circuit base material with an underfill material after bonding the semiconductor chip to the inner layer circuit base material.

[0254] The method for manufacturing a circuit board according to the first example includes a step of forming a sealing layer as a cured product layer for sealing at least a part of the semiconductor chip after bonding the semiconductor chip to the inner layer circuit base material. The formation of the sealing layer can be performed by a method including the above-described steps (I) to (VI). Since the formed sealing layer is a cured product layer formed by a method including steps (I) to (VI), it can have a polished surface with suppressed formation of recesses. Therefore, layer formation on the polished surface can be performed smoothly.

[0255] Hereinafter, a method for manufacturing a semiconductor chip package will be described as a second example of a circuit board. FIG. 7 is a cross-sectional view schematically showing a semiconductor chip package as a circuit board according to the second example of the present invention. As shown in FIG. 7, the semiconductor chip package 600 described in this second example includes a semiconductor chip 610; a sealing layer 620 formed so as to cover the periphery of the semiconductor chip 610; a redistribution formation layer 630 as an insulating layer provided on the surface of the semiconductor chip 610 opposite to the sealing layer 620; a redistribution layer 640 as a conductor layer; a solder resist layer 650; and bumps 660. In the second example, one or both of the sealing layer 620 and the redistribution formation layer 630 can be formed by a cured product layer.

[0256] The semiconductor chip package described in this second example (1) A step of laminating a temporary fixing film on a substrate to obtain a temporary base material; (2) A step of temporarily fixing a semiconductor chip on the temporary fixing film of the temporary base material; (3) A step of forming a sealing layer on the semiconductor chip; (4) A step of peeling the temporary base material from the semiconductor chip; (5) A step of forming a redistribution formation layer on the surface of the semiconductor chip from which the temporary base material has been peeled, and (6) A step of forming a redistribution layer as a conductor layer on the redistribution formation layer It can be manufactured by a method including these steps in this order. In this manufacturing method, the formation of the sealing layer in step (3) or the formation of the redistribution formation layer in step (5) may be performed by a method including the above-described steps (I) to (VI).

[0257] In step (1), a temporary fixing film is laminated on a substrate to obtain a temporary base material. As the substrate and the temporary fixing film, for example, those described above are used.

[0258] In step (2), a semiconductor chip is temporarily fixed on the temporary fixing film of the temporary base material. Usually, the semiconductor chip is temporarily fixed on the temporary fixing film such that the electrode pad surface of the semiconductor chip is joined to the temporary fixing film. The temporary fixing of the semiconductor chip can be performed using a known apparatus such as a flip chip bonder or a die bonder. The layout and the number of arrangements of the semiconductor chips can be appropriately set according to the shape and size of the temporary fixing film and the production number of the target semiconductor chip package. For example, the semiconductor chips may be aligned and temporarily fixed in a matrix pattern with multiple rows and multiple columns.

[0259] In step (3), a sealing layer is formed on the semiconductor chip. The sealing layer may be formed of a cured product layer using a method including the above-described steps (I) to (VI).

[0260] In step (4), the temporary base material is peeled off from the semiconductor chip. The method for peeling the dissociation base material can be appropriately selected according to the material of the temporary fixing film. For example, methods such as heating and foaming (or expanding) the temporary fixing film for peeling, and irradiating ultraviolet rays through the substrate to reduce the adhesive force of the temporary fixing film for peeling can be mentioned. In the method of heating and foaming (or expanding) the temporary fixing film for peeling, the heating conditions are usually 100°C to 250°C for 1 second to 90 seconds or 5 minutes to 15 minutes. Also, in the method of irradiating ultraviolet rays through the substrate to reduce the adhesive force of the temporary fixing film for peeling, the irradiation amount of ultraviolet rays is usually 10 mJ / cm 2 ~1000 mJ / cm 2 is used.

[0261] In step (5), a redistribution formation layer is formed on the surface of the semiconductor chip from which the temporary base material has been peeled off. The redistribution formation layer may be formed by a cured product layer using the method including the above-described steps (I) to (VI). After forming the redistribution formation layer, via holes may be formed in the redistribution formation layer in order to make an interlayer connection between the semiconductor chip and a conductor layer described later. The via holes can be formed, for example, by the method described in step (VII).

[0262] In step (6), a redistribution layer as a conductor layer is formed on the redistribution formation layer. The formation of the redistribution layer can be formed, for example, by the method described in step (IX). At this time, the redistribution layer is formed on the polished surface of the cured product layer that forms the redistribution formation layer. Since the formation of recessed portions is suppressed on this polished surface, it is possible to suppress the formation of unintended defects in the redistribution layer formed on the polished surface.

[0263] In the method for manufacturing a semiconductor chip package according to the second example, steps (5) and (6) may be repeated to alternately stack (build up) the conductor layer (redistribution layer) and the redistribution formation layer (insulating layer). Also, the method for manufacturing a semiconductor chip package may further include (7) a step of forming a solder resist layer on the conductor layer (redistribution layer), (8) a step of forming bumps, and (9) a step of dicing and singulating a plurality of semiconductor chip packages into individual semiconductor chip packages.

[0264] The second example described above is an example of a method in which a semiconductor chip is first provided and a rewiring layer is formed on the electrode pad surface thereof (i.e., the Chip-1 st ) method). In addition to such a Chip-1 method, a semiconductor chip package may be manufactured by a method in which a rewiring layer is first provided, and a semiconductor chip is provided and sealed on the rewiring layer in a state where the electrode pad surface thereof can be electrically connected to the rewiring layer (i.e., the Rewiring Layer-1st (RDL-1 st ) method). The method for manufacturing a circuit board according to the above-described embodiment is applicable regardless of whether it is the Chip-1 st method or the RDL-1 st method.

[0265] <Semiconductor Device> The above-described circuit board can be used in the manufacture of a semiconductor device. The semiconductor device includes the above-described circuit board. Examples of the semiconductor device include various semiconductor devices used in electric products (e.g., computers, mobile phones, smartphones, tablet devices, wearable devices, digital cameras, medical devices, and televisions, etc.) and vehicles (e.g., motorcycles, automobiles, trains, ships, and airplanes, etc.).

Example

[0266] Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples. In the following description, "parts" and "%" representing amounts are based on mass unless otherwise specified. Further, the operations described below were performed in an environment of normal temperature and pressure (23°C, 1 atm) in the air unless otherwise specified.

[0267] <Synthesis Example 1> 69 g of a bifunctional hydroxy group-terminated polybutadiene (manufactured by Nippon Soda Co., Ltd., "G-3000", number average molecular weight = 3000, hydroxy group equivalent = 1800 g / eq.), 40 g of Ipzol 150 (an aromatic hydrocarbon-based mixed solvent: manufactured by Idemitsu Petrochemical Co., Ltd.), and 0.005 g of dibutyltin laurate were mixed and dissolved uniformly. When it became uniform, the temperature was raised to 50 °C, and while stirring further, 8 g of isophorone diisocyanate (manufactured by Evonik Degussa Japan Co., Ltd., IPDI, isocyanate group equivalent = 113 g / eq.) was added and the reaction was carried out for about 3 hours. Next, after cooling this reaction product to room temperature, 23 g of a cresol novolak resin (manufactured by DIC Corporation, "KA-1160", hydroxy group equivalent = 117 g / eq.) and 60 g of ethyl diglycol acetate (manufactured by Daicel Corporation) were added thereto, and while stirring, the temperature was raised to 80 °C and the reaction was carried out for about 4 hours. The disappearance of the NCO peak at 2250 cm -1 was confirmed by FT-IR. The disappearance of the NCO peak was regarded as the end point of the reaction, and after cooling the reaction product to room temperature, it was filtered through a 100-mesh filter cloth to obtain a polymer resin A (nonvolatile component 50 mass%).

[0268] <Formulation Example 1> 3 parts of a bisphenol type epoxy resin (manufactured by Nippon Steel Chemical & Material Co., Ltd., "ZX-1059", a 1:1 mixture of bisphenol A type and bisphenol F type, epoxy equivalent 169 g / eq.), 4 parts of a naphthalene type epoxy resin (manufactured by DIC Corporation, "HP-4032D", 1,6-bis(glycidyloxy)naphthalene, epoxy equivalent about 145 g / eq.), Inorganic filler 1 (spherical silica surface-treated with an amine-based alkoxysilane compound (manufactured by Shin-Etsu Chemical Co., Ltd., "KBM573"), average particle size 3.5 μm, 99% particle size 9.5 μm, specific surface area 4.5 m 2110 parts of / g), 4 parts of a compound having a methacryloyl group and a polyethylene oxide structure ("BPE-1300N" manufactured by Shin-Nakamura Chemical Co., Ltd., methacryloyl group equivalent: 842 g / eq.), an acid anhydride-based curing agent ("HNA-100" manufactured by Shin Nippon Rika Co., Ltd., acid anhydride group equivalent: 179 g / eq.) 10 parts, silane coupling agent ("KBM403" (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd.) 0.1 part, curing accelerator (imidazole-based curing accelerator "2MA-OK-PW" manufactured by Shikoku Kasei Kogyo Co., Ltd.) 0.5 part were uniformly dispersed using a mixer to prepare Resin Composition 1.

[0269] <Formulation Example 2> Instead of 110 parts of Inorganic Filler 1 (spherical silica surface-treated with an amine-based alkoxysilane compound ("KBM573" manufactured by Shin-Etsu Chemical Co., Ltd.)), Inorganic Filler 2 (spherical silica surface-treated with an amine-based alkoxysilane compound ("KBM573" manufactured by Shin-Etsu Chemical Co., Ltd.), average particle size 1.0 μm, 99% particle size 4.5 μm, specific surface area 4.7 m 2 / g) 90 parts were used, and Resin Composition 2 was prepared in the same manner as in Formulation Example 1.

[0270] <Formulation Example 3> 3 parts of liquid bisphenol A type epoxy resin (“jER828EL” manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 180 g / eq.), 4 parts of naphthylene ether type epoxy resin (“HP6000L” manufactured by DIC Corporation, epoxy equivalent 215 g / eq.), 3 parts of bixylenol type epoxy resin (“YX4000HK” manufactured by Mitsubishi Chemical Corporation, epoxy equivalent about 185 g / eq.), 3 parts of cresol novolak resin (“KA-1160” manufactured by DIC Corporation, hydroxyl equivalent 117 g / eq.), 2 parts of carbodiimide resin (“V-03” manufactured by Nisshinbo Chemical Inc., carbodiimide equivalent 216 g / eq., toluene solution with non-volatile component 50 mass%), 16.9 parts of active ester compound (“HPC-8000-65T” manufactured by DIC Corporation, weight average molecular weight about 2700, active group equivalent about 223 g / eq., toluene solution with non-volatile component 65 mass%), 10 parts of phenoxy resin (“YX7553BH30” manufactured by Mitsubishi Chemical Corporation, cyclohexanone:methyl ethyl ketone (MEK) 1:1 solution with solid content 30 mass%), 40 parts of inorganic filler 3 (spherical silica surface-treated with an amine-based alkoxysilane compound (“KBM573” manufactured by Shin-Etsu Chemical Co., Ltd.), average particle size 0.1 μm, 99% particle size 0.4 μm, specific surface area 10.4 m 2 / g), 0.05 part of 4-dimethylaminopyridine (DMAP), 6 parts of methyl ethyl ketone, and 5 parts of cyclohexanone were uniformly dispersed using a mixer to prepare resin composition 3.

[0271] <Formulation Example 4> 40 parts of inorganic filler 3 (spherical silica surface-treated with an amine-based alkoxysilane compound (“KBM573” manufactured by Shin-Etsu Chemical Co., Ltd.)) was not used. Also, the amount of methyl ethyl ketone was changed to 4 parts. Furthermore, 5 parts of cyclohexanone was not used. Except for the above matters, resin composition 4 was prepared in the same manner as in Formulation Example 3.

[0272] <Formulation Example 5> 4 parts of bisphenol type epoxy resin (“ZX-1059” manufactured by Nippon Steel Chemical & Material Co., Ltd., a 1:1 mixture of bisphenol A type and bisphenol F type, epoxy equivalent 169 g / eq.), 4 parts of biphenyl type epoxy resin (“NC3000L” manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 269 g / eq.), 2 parts of naphthylene ether type epoxy resin (“HP6000L” manufactured by DIC Corporation, epoxy equivalent 215 g / eq.), 0.5 part of flame retardant (“HCA-HQ” manufactured by Sanko Chemical Co., Ltd., 10-(2,5-dihydroxyphenyl)-10-hydroxy-9-oxa-10-phosphaphenanthrene-10-oxide, average particle size 2 μm), 2 parts of cresol novolak resin (“KA-1160” manufactured by DIC Corporation, hydroxyl equivalent = 117 g / eq.), 0.5 part of benzoxazine compound (“ODA-BOZ” manufactured by JFE Chemical Corporation, benzoxazine ring equivalent 218 g / eq.), 4.6 parts of active ester compound (“HPC-8000-65T” manufactured by DIC Corporation, toluene solution of non-volatile component with weight average molecular weight of about 2700 and active group equivalent of about 223 g / eq. and 65% by mass), 4 parts of polymer resin A (non-volatile component 50% by mass), 90 parts of inorganic filler 1 (spherical silica surface-treated with an amine-based alkoxysilane compound (“KBM573” manufactured by Shin-Etsu Chemical Co., Ltd.), average particle size 3.5 μm, 99% particle size 9.5 μm, specific surface area 4.5 m 2 / g), 0.05 part of 4-dimethylaminopyridine (DMAP), 6 parts of methyl ethyl ketone, and 6 parts of cyclohexanone were uniformly dispersed using a mixer to prepare resin composition 5.

[0273] <Formulation Example 6> Instead of 90 parts of inorganic filler 1 (spherical silica surface-treated with an amine-based alkoxysilane compound (“KBM573” manufactured by Shin-Etsu Chemical Co., Ltd.)), 70 parts of inorganic filler 2 (spherical silica surface-treated with an amine-based alkoxysilane compound (“KBM573” manufactured by Shin-Etsu Chemical Co., Ltd.) (average particle size 1.0 μm, 99% particle size 4.5 μm, specific surface area 4.7 m 2 / g) were used. Also, the amount of methyl ethyl ketone was changed to 5 parts. Further, the amount of cyclohexanone was changed to 5 parts. Except for the above matters, resin composition 6 was prepared in the same manner as in Formulation Example 5.

[0274] <Formulation Example 7> A resin composition 7 was prepared in the same manner as in Example 1, except that the amount of the inorganic filler 1 (spherical silica surface-treated with an amine-based alkoxysilane compound “KBM573” manufactured by Shin-Etsu Chemical Co., Ltd.) was changed to 70 parts.

[0275] <Formulation Example 8> The amount of the polymer resin A (non-volatile component: 50% by mass) was changed to 20 parts. Also, the amount of the inorganic filler 1 (spherical silica surface-treated with an amine-based alkoxysilane compound “KBM573” manufactured by Shin-Etsu Chemical Co., Ltd.) was changed to 70 parts. A resin composition 8 was prepared in the same manner as in Formulation Example 5, except for the above matters.

[0276] <Formulation Example 9> Instead of 40 parts of the inorganic filler 3 (spherical silica surface-treated with an amine-based alkoxysilane compound “KBM573” manufactured by Shin-Etsu Chemical Co., Ltd.), 40 parts of the inorganic filler 4 (spherical silica surface-treated with an amine-based alkoxysilane compound “KBM573” manufactured by Shin-Etsu Chemical Co., Ltd., average particle diameter 0.3 μm, 99% particle diameter 1.0 μm, specific surface area 10.3 m 2 / g) was used, and a resin composition 9 was prepared in the same manner as in Formulation Example 3, except for this.

[0277] <Measurement Test of Elastic Modulus> Using the resin compositions 1, 2, and 7 of Formulation Examples 1, 2, and 7, cured sample were prepared by the following method. That is, the resin composition was compression-molded on a release-treated 12-inch silicon wafer using a compression molding apparatus (mold temperature: 130 °C, pressure: 6 MPa, cure time: 10 minutes) to form a resin composition layer with a thickness of 300 μm. Then, the resin composition was peeled off from the silicon wafer and heated at 180 °C for 90 minutes to thermally cure the resin composition, and a cured sample was obtained.

[0278] Using Resin Compositions 3 to 6, 8, and 9 of Other Formulation Examples, cured sample was prepared by the following method. That is, the resin composition was uniformly applied onto a release-treated PET film (manufactured by Lintec Corporation, "PET501010") using a die coater so that the thickness of the resin composition layer after drying was 100 μm, and dried at 80°C to 110°C (average 95°C) for 6 minutes. Thereafter, heat treatment was performed at 180°C for 90 minutes to cure the resin composition layer, and the support was peeled off to obtain a cured sample.

[0279] Regarding the elastic modulus of this cured sample, dynamic mechanical analysis was performed in tensile mode using a dynamic mechanical analyzer (manufactured by Seiko Instruments Inc., "DMS-6100"). Specifically, after mounting the cured sample on the said apparatus, measurement was carried out under the measurement conditions of a frequency of 1 Hz and a heating rate of 5°C / min. The value of the storage elastic modulus (E') in GPa at 25°C in such measurement was read.

[0280] <Measurement Test of Dielectric Loss Tangent> The dielectric loss tangent of the cured sample prepared by the same method as the <Measurement Test of Elastic Modulus> described above was measured by the cavity resonance perturbation method using a measuring apparatus (manufactured by Agilent Technologies, "HP8362B") under the measurement conditions of a measurement temperature of 23°C and a measurement frequency of 5.8 GHz. Measurement was performed on two test pieces, and the average value was calculated.

[0281] <Manufacture of Resin Sheet> Using each of the resin compositions 3, 4, 5, 6, 8, and 9 prepared in Formulation Examples 3, 4, 5, 6, 8, and 9, a resin sheet having a resin composition layer with a dry thickness of 80 μm and a resin sheet having a resin composition layer with a dry thickness of 100 μm were manufactured by the following method.

[0282] As a support, a PET film (Toray Industries, Inc.'s "Lumirror R80", thickness 38 μm, softening point 130 °C, hereinafter sometimes referred to as "release PET") that had been subjected to a release treatment with an alkyd resin-based release agent ("AL-5" manufactured by Lintec Corporation) was prepared. The resin composition was uniformly applied onto the support using a die coater and dried at 70 °C to 95 °C for 2 minutes to obtain a resin composition layer on the support. Next, the rough surface of a polypropylene film ("Alpha MA-411" manufactured by Oji Fibrex Corporation, thickness 15 μm) as a protective film was laminated onto the surface of the resin sheet that was not joined to the support so as to be joined to the resin composition layer. Thereby, a resin sheet including a support, a resin composition layer, and a protective film in this order was obtained.

[0283] <Example 1> On a 12-inch silicon wafer (thickness 775 μm), the resin composition 1 manufactured in Formulation Example 1 was compression molded using a compression molding apparatus (mold temperature: 130 °C, pressure: 6 MPa, cure time: 10 minutes) to form a first resin composition layer with a thickness of 200 μm. Thereafter, it was heated at 180 °C for 90 minutes to thermally cure the first resin composition layer to obtain a first cured layer with a thickness of 200 μm. Thereafter, the first cured layer was polished using a grinder to make the thickness of the first cured layer 150 μm.

[0284] The protective film was peeled off from a resin sheet (thickness of the resin composition layer 80 μm) manufactured using the resin composition 4 of Formulation Example 4. This resin sheet was laminated onto the first cured layer so that the resin composition layer of the resin sheet and the first cured layer were joined to form a second resin composition layer. The lamination was performed by reducing the pressure for 30 seconds to make the atmospheric pressure 13 hPa or less, and then pressure-bonding at 100 °C and a pressure of 0.74 MPa for 30 seconds. The laminations described below were all performed under the same conditions as this unless otherwise specified. After peeling off the support, the second resin composition was thermally cured by heating at 180 °C for 90 minutes to obtain a second cured layer. Thereafter, the second cured layer was polished using a grinder to make the thickness of the second cured layer 20 μm. Thus, a cured product layer (thickness 170 μm) including the first cured layer (thickness 150 μm) and the second cured layer (thickness 20 μm) in this order was obtained from the silicon wafer side. Hereinafter, a member having the layer structure of the silicon wafer / first cured layer / second cured layer obtained by the above method may be referred to as "evaluation substrate A". Regarding this evaluation substrate A, evaluations were performed by the following Vickers hardness measurement test, dent evaluation test, warp evaluation test, and wettability evaluation test.

[0285] (Vickers hardness measurement test) The evaluation substrate A was cut into a rectangle of 3 cm × 4 cm. The Vickers hardness (HV) was measured using a Vickers hardness tester (manufactured by Mitutoyo Corporation) on the surface of the cured product layer.

[0286] (Dent evaluation test) The evaluation substrate A was cut into a square of 1 cm × 1 cm. The entire surface of the cured product layer was observed with a scanning electron microscope (SEM), and the number of dents derived from the inorganic filler was counted. When there were 30 or more dents with a diameter of 5 μm or more, it was judged as "defective", when there were 10 or more and less than 30, it was judged as "acceptable", and when there were less than 10, it was judged as "good".

[0287] (Warp evaluation test) Using a shadow moire measurement device ("Thermoire AXP" manufactured by Akorometrix), the warp amount of the evaluation substrate A was measured in a room at 25°C. The measurement was performed in accordance with JEITA EDX-7311-24 of the Electronic Information Technology Industry Association standard. Specifically, a virtual plane was calculated from all the data on the substrate surface (the surface of the cured product layer) in the measurement area by the least squares method. Using this virtual plane as a reference plane, the difference between the minimum value and the maximum value of the distance in the vertical direction (the vertical direction with respect to the reference plane) from the reference plane to the substrate surface was obtained as the warp amount.

[0288] The obtained warp amount was evaluated according to the following criteria. "Excellent": The warp amount was less than 2500 μm, and it was evaluated that the warp amount was particularly small. "Good": The warpage amount was 2500 μm or more and less than 3000 μm, and it was evaluated that the warpage amount was sufficiently small. "Acceptable": The warpage amount was 3000 μm or more and less than 4000 μm, and it was evaluated that the warpage amount was small. "Defective": The warpage amount was 4000 μm or more, and it was evaluated that the warpage amount was large.

[0289] (Wettability evaluation test) On the surface of the cured product layer of evaluation substrate A, a photosensitive polyimide resin (viscosity 6 Pa·s) was spin-coated using a spin coater ("MS-A150" manufactured by Mikasa Co., Ltd.) under the condition of a rotation speed of 2000 rpm. The applied photosensitive polyimide resin was pre-baked on a hot plate at 120 °C for 4 minutes. As a result, a thin film layer with a thickness of 5 μm was obtained on the cured product layer. The thin film layer was observed, and the wettability of the surface of the cured product layer was evaluated according to the following criteria. "Good": There are no repellency and dents of the photosensitive polyimide resin on the surface of the cured product layer. "Defective": There is repellency or dents of the photosensitive polyimide resin on the surface of the cured product layer.

[0290] <Example 2> The production and evaluation of evaluation substrate A were carried out in the same manner as in Example 1, except that a resin sheet (resin composition layer thickness 80 μm) manufactured using resin composition 3 of Formulation Example 3 was used instead of the resin sheet (resin composition layer thickness 80 μm) manufactured using resin composition 4 of Formulation Example 4.

[0291] <Example 3> The production and evaluation of evaluation substrate A were carried out in the same manner as in Example 1, except that resin composition 2 manufactured in Formulation Example 2 was used instead of resin composition 1 manufactured in Formulation Example 1.

[0292] <Example 4> The resin composition 2 produced in Formulation Example 2 was used instead of the resin composition 1 produced in Formulation Example 1, and the resin sheet (thickness of the resin composition layer: 80 μm) produced using the resin composition 4 of Formulation Example 4 was replaced with the resin sheet (thickness of the resin composition layer: 80 μm) produced using the resin composition 3 of Formulation Example 3. The evaluation substrate A was manufactured and evaluated in the same manner as in Example 1, except for the above changes.

[0293] <Example 5> A protective film was peeled off from a resin sheet (thickness of the resin composition layer: 100 μm) produced using the resin composition 5 of Formulation Example 5. This resin sheet was laminated onto a 12-inch silicon wafer (thickness: 775 μm) using a batch-type vacuum pressure laminator (two-stage build-up laminator "CVP700" manufactured by Nikkō Materials Co., Ltd.) so that the resin composition layer was joined to the silicon wafer, and the support was peeled off. Onto this resin composition layer, the above resin sheet (a resin sheet having a resin composition layer with a thickness of 100 μm produced using the resin composition 5 of Formulation Example 5. The protective film had been peeled off) was laminated again to form a first resin composition layer with a thickness of 200 μm. Thereafter, the support was peeled off.

[0294] Thereafter, it was heated at 100 °C for 30 minutes and further heated at 180 °C for 90 minutes to thermally cure the first resin composition layer and obtain a first cured layer with a thickness of 200 μm. Thereafter, the first cured layer was polished using a grinder to make the thickness of the first cured layer 150 μm.

[0295] A protective film was peeled off from a resin sheet (thickness of the resin composition layer: 80 μm) produced using the resin composition 4 of Formulation Example 4. This resin sheet was laminated onto the first cured layer so that the resin composition layer of the resin sheet was joined to the first cured layer to form a second resin composition layer. After the support was peeled off, the second resin composition layer was cured by heating at 180 °C for 90 minutes to obtain a second cured layer.

[0296] After that, the second cured layer was polished using a grinder to make the thickness of the second cured layer 20 μm. Thus, a cured product layer (170 μm thick) including the first cured layer (150 μm thick) and the second cured layer (20 μm thick) in this order was obtained from the silicon wafer side. Hereinafter, a member having the layer structure of the silicon wafer / first cured layer / second cured layer obtained by the above method may be referred to as "evaluation substrate B". Regarding this evaluation substrate B, evaluation was performed by the Vickers hardness measurement test, dent evaluation test, warp evaluation test, and wettability evaluation test described in Example 1.

[0297] <Example 6> The evaluation substrate B was manufactured and evaluated in the same manner as in Example 5, except that a resin sheet (resin composition layer thickness: 80 μm) manufactured using resin composition 3 of Formulation Example 3 was used instead of the resin sheet (resin composition layer thickness: 80 μm) manufactured using resin composition 4 of Formulation Example 4.

[0298] <Production Example 7> The evaluation substrate B was manufactured and evaluated in the same manner as in Example 5, except that a resin sheet (resin composition layer thickness: 100 μm) manufactured using resin composition 6 of Formulation Example 6 was used instead of the resin sheet (resin composition layer thickness: 100 μm) manufactured using resin composition 5 of Formulation Example 5.

[0299] <Production Example 8> The evaluation substrate B was manufactured and evaluated in the same manner as in Example 5, except that a resin sheet (resin composition layer thickness: 100 μm) manufactured using resin composition 6 of Formulation Example 6 was used instead of the resin sheet (resin composition layer thickness: 100 μm) manufactured using resin composition 5 of Formulation Example 5, and a resin sheet (resin composition layer thickness: 80 μm) manufactured using resin composition 3 of Formulation Example 3 was used instead of the resin sheet (resin composition layer thickness: 80 μm) manufactured using resin composition 4 of Formulation Example 4.

[0300] <Example 9> The production and evaluation of evaluation substrate A were carried out in the same manner as in Example 1, except that the resin composition 7 produced in Formulation Example 7 was used instead of the resin composition 1 produced in Formulation Example 1.

[0301] <Example 10> In the same manner as in Example 1, formation of the first resin composition layer on a silicon wafer (thickness: 775 μm), formation of the first cured layer by thermosetting, and polishing of the first cured layer were carried out.

[0302] A protective film was peeled off from a resin sheet (thickness of the resin composition layer: 80 μm) produced using the resin composition 3 of Formulation Example 3. This resin sheet was laminated on the first cured layer such that the resin composition layer was joined to the first cured layer, and the support was peeled off. Further, on this resin composition layer, the above resin sheet (a resin sheet having a resin composition layer with a thickness of 80 μm produced using the resin composition 3 of Formulation Example 3. The one from which the protective film was peeled off) was laminated to form a second resin composition layer with a thickness of 160 μm. Thereafter, the support was peeled off. Thereafter, the second resin composition was thermoset by heating at 180°C for 90 minutes to obtain a second cured layer. Thereafter, the second cured layer was polished using a grinder to make the thickness of the second cured layer 100 μm. Thus, a cured product layer (thickness: 250 μm) including the first cured layer (thickness: 150 μm) and the second cured layer (thickness: 100 μm) in this order from the silicon wafer side was obtained. Hereinafter, the member having the layer structure of silicon wafer / first cured layer / second cured layer obtained by the above method may be referred to as "evaluation substrate C". Evaluation of this evaluation substrate C was carried out by the Vickers hardness measurement test, dent evaluation test, warp evaluation test, and wettability evaluation test described in Example 1.

[0303] <Example 11> The production and evaluation of evaluation substrate A were carried out in the same manner as in Example 1, except that a resin sheet (thickness of the resin composition layer: 80 μm) produced using the resin composition 9 of Formulation Example 9 was used instead of the resin sheet (thickness of the resin composition layer: 80 μm) produced using the resin composition 4 of Formulation Example 4.

[0304] <Comparative Example 1> A member having a layer structure of a silicon wafer / first cured layer (thickness: 150 μm) (hereinafter sometimes referred to as "evaluation substrate D") was produced in the same manner as in Example 7, except that the post-polishing operation of the first cured layer (i.e., lamination, thermosetting, and polishing of the resin sheet produced using the resin composition 4 of Formulation Example 4) was not performed. For this evaluation substrate D, evaluation was carried out by the dent evaluation test, warp evaluation test, and wettability evaluation test described in Example 1. In this Comparative Example 1, since the second cured layer was not formed, in the dent evaluation test and the wettability evaluation test, the surface of the first cured layer was evaluated. In the warp evaluation test, the warp amount was determined with the surface of the first cured layer as the substrate surface.

[0305] <Results> The compositions of the resin compositions prepared in the above-described formulation examples are shown in Table 1 below. In Table 1, the amounts of the respective components represent the amounts (parts by mass) of the non-volatile components.

[0306] Also, the results of the above-described Examples and Comparative Examples are shown in Tables 2 and 3 below. In Tables 2 and 3, the meanings of the abbreviations are as follows. "Particle size ratio D1 / D2": The ratio D1 / D2 of the average particle size D1 of the (A) first inorganic filler contained in the first resin composition to the average particle size D2 of the (a) second inorganic filler contained in the second resin composition. "First cured layer (before polishing)" in the "Thickness" column: The thickness of the first cured layer before polishing. "First cured layer (after polishing)" in the "Thickness" column: The thickness of the first cured layer after polishing. "First cured layer + second cured layer (before polishing)" in the "Thickness" column: The thickness of the cured layer composed of the first cured layer and the second cured layer before polishing the second cured layer. "First cured layer + second cured layer (after polishing)" in the "Thickness" column: The thickness of the cured layer composed of the first cured layer and the second cured layer after polishing the second cured layer. "Warp": The result of the warp evaluation test of Evaluation Substrates A to D. "Dent": The result of the dent evaluation test of the polished surface of the cured layer of Evaluation Substrates A to D. "Vickers hardness (HV)": The Vickers hardness of the polished surface of the cured layer of Evaluation Substrates A to D. "Elastic modulus ratio (G1 / G2)": The ratio of the elastic modulus G1 of the first cured layer to the elastic modulus G2 of the second cured layer. "Elastic modulus G1 (GPa)": The elastic modulus of the first cured layer. "Elastic modulus G2 (GPa)": The elastic modulus of the second cured layer. "Df": The dielectric loss tangent of the first cured layer. "Wettability": The wettability of the polished surface of the cured material layer.

[0307]

Table 1

[0308]

Table 2

[0309]

Table 3

Explanation of Symbols

[0310] 10 Inorganic filler 11 Particles of inorganic filler 12 Particles of inorganic filler 13 Void 20 Curing resin 30 First resin composition 40 Curing resin 50 Second resin composition 100 Substrate 100U Surface of the substrate 200 First cured layer 200U Surface of the first cured layer 210 First resin composition layer 220 Recessed part 230 Recessed part 300 Second cured layer 300U Surface of the second cured layer 310 Second resin composition layer 400 Cured material layer 500 Circuit board 600 Semiconductor chip package 610 Semiconductor chip 620 Encapsulation layer 630 Rewiring formation layer 640 Rewiring layer 650 Solder resist layer 660 Bump

Claims

1. A step of forming a first resin composition layer with a first resin composition containing an inorganic filler and a curable resin, A step of curing the first resin composition layer to form a first cured layer, A step of polishing the surface of the first cured layer, A step of forming a second resin composition layer on the polished surface of the first cured layer with a second resin composition containing a curable resin, A step of curing the second resin composition layer to form a second cured layer, and A step of polishing the surface of the second cured layer opposite to the first cured layer, in this order; The second resin composition does not contain an inorganic filler or contains one; A method for manufacturing a circuit board, wherein when the second resin composition contains an inorganic filler, the 99% particle size of the inorganic filler is 2 μm or less.

2. The method for manufacturing a circuit board according to claim 1, wherein the 99% particle size of the inorganic filler contained in the first resin composition is larger than 2 μm.

3. The method for manufacturing a circuit board according to claim 1, wherein the average particle size of the inorganic filler contained in the second resin composition is smaller than the average particle size of the inorganic filler contained in the first resin composition.

4. The method for manufacturing a circuit board according to claim 1, wherein the Vickers hardness of the surface of the polished second cured layer is 10 HV or more.

5. The method for manufacturing a circuit board according to claim 1, wherein the elastic modulus G1 of the first cured layer is 10 GPa or more.

6. The method for manufacturing a circuit board according to claim 1, wherein the ratio G1 / G2 of the elastic modulus G1 of the first cured layer to the elastic modulus G2 of the second cured layer is 1.1 or more.

7. The method for manufacturing a circuit board according to claim 1, including a step of forming a conductor layer on the surface of the polished second cured layer.

8. The method for manufacturing a circuit board according to claim 1, wherein the circuit board is a semiconductor chip package.

9. The method for manufacturing a circuit board according to claim 1, wherein a sealing layer or a redistribution formation layer is formed by the first cured layer and the second cured layer.

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