Circuit board manufacturing method

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 rewiring formation layer as an insulating layer for insulating between rewiring layers connected to a semiconductor chip may be formed by a cured product layer. The resin composition for forming such a cured product layer sometimes contained 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] For 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 a cured layer containing an inorganic filler is polished to form a polished surface, unintended depressions may form on the polished surface. Stable layer formation is not possible on a polished surface where depressions are formed, and defects may occur in that layer. For example, when forming a thin film layer on a polished surface using a photosensitive resin composition, the thin film layer may not be able to form on the depressions, resulting in the formation of defects. If the thin film layer is an insulating layer that insulates between wirings, or if the thin film layer is used as a photoresist to form wiring, unintended conductivity may occur in the defective areas, potentially causing insulation failure.

[0006] This invention was conceived in view of the above-mentioned problems, and aims to provide a method for manufacturing a circuit board comprising a hardened material layer having a polished surface in which the formation of recesses is suppressed. [Means for solving the problem]

[0007] The inventors diligently studied to solve the aforementioned problems. As a result, the inventors discovered that the formation of recesses can be suppressed by further forming, curing, and polishing a resin composition layer on the polished surface, and thus completed the present invention. In other words, 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 the first cured layer, The process of polishing the surface of the first hardened layer, A step of forming a second resin composition layer on the polished surface of the first cured layer using a second resin composition containing a curable resin. A step of curing the second resin composition layer to form a second cured layer, and This process includes, in this order, polishing the side of the second hardened layer opposite to the first hardened layer; The second resin composition either does not contain or contains inorganic fillers; 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 99% particle size of the inorganic filler contained in the first resin composition is greater than 2 μm. <1> The method for manufacturing a circuit board as described above. <3> 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. <1> or <2> The method for manufacturing a circuit board as described above. <4> The Vickers hardness of the polished second hardened layer surface is 10 HV or higher. <1> ~ <3> A method for manufacturing a circuit board as described in any one of the items. <5> The elastic modulus G1 of the first hardened layer is 10 GPa or higher. <1> ~ <4> A method for manufacturing a circuit board as described in any one of the items. <6> The ratio G1 / G2 of the elastic modulus G1 of the first hardened layer to the elastic modulus G2 of the second hardened layer is 1.1 or greater. <1> ~ <5> A method for manufacturing a circuit board as described in any one of the items. <7> The process includes forming a conductive layer on the polished surface of the second hardened layer, <1> ~ <6> A method for manufacturing a circuit board as described in any one of the items. <8> The circuit board is a semiconductor chip package. <1> ~ <7> A method for manufacturing a circuit board as described in any one of the items. <9> A sealing layer or a rewiring layer is formed by the first and second curing layers. <1> ~ <8> A method for manufacturing a circuit board as described in any one of the items. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a method for manufacturing a circuit board that includes a cured material layer having a polished surface in which the formation of recesses is suppressed. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic cross-sectional view showing a method for manufacturing a circuit board according to one embodiment of the present invention. [Figure 2] Figure 2 is a schematic cross-sectional view showing a method for manufacturing a circuit board according to one embodiment of the present invention. [Figure 3] Figure 3 is a schematic cross-sectional view showing a method for manufacturing a circuit board according to one embodiment of the present invention. [Figure 4] Figure 4 is a schematic cross-sectional view showing a method for manufacturing a circuit board according to one embodiment of the present invention. [Figure 5] Figure 5 is a schematic cross-sectional view showing a method for manufacturing a circuit board according to one embodiment of the present invention. [Figure 6] Figure 6 is a schematic cross-sectional view showing a method for manufacturing a circuit board according to one embodiment of the present invention. [Figure 7] Figure 7 is a schematic cross-sectional view showing a semiconductor chip package as a circuit board according to a second example of the present invention. [Modes for carrying out the invention]

[0011] The present invention will be described in detail below with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples described below, and may be implemented with modifications as appropriate without departing from the scope of the claims and their equivalents.

[0012] In the following explanation, the term "(meth)acrylic acid" includes acrylic acid, methacrylic acid, and combinations thereof. Similarly, the term "(meth)acrylate" includes acrylate, methacrylate, and combinations thereof.

[0013] <Overview of circuit board manufacturing method> A method for manufacturing a circuit board according to one embodiment of the present invention is: Step (I) to form a first resin composition layer with a first resin composition containing an inorganic filler and a curable resin, (II) A step of curing the first resin composition layer to form the first cured layer, (III) Steps to polish the surface of the first hardened layer, (IV) 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. (V) A step of curing the second resin composition layer to form a second cured layer, and (VI) A step in which the side of the second hardened layer opposite to the first hardened layer is polished. It includes them in this order. Furthermore, the second resin composition may or may not contain an inorganic filler. If the second resin composition contains an inorganic filler, the 99% particle size of the inorganic filler in the second resin composition is within a small range below a specific value. Here, the 99% particle size of the inorganic filler refers to the particle size at which the cumulative volume from the smallest diameter side in the volume-based particle size distribution of the inorganic filler accounts for 99%.

[0014] According to the circuit board manufacturing method of this embodiment, it is possible to manufacture a circuit board having a cured material layer with a polished surface in which the formation of recesses is suppressed. The mechanism by which this effect is obtained will be explained below, using the case of forming a cured material layer on a substrate as an example.

[0015] Figures 1 to 6 are schematic cross-sectional views showing a method for manufacturing a circuit board according to one embodiment of the present invention. The method for manufacturing a circuit board according to one example includes, in this order, a step (I) of forming a first resin composition layer 210 on the 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 Figure 2; and a step (III) of polishing the surface 200U of the first cured layer 200, as shown in Figure 3. Polishing reduces the thickness of the first cured layer 200 and also forms a polished surface on the surface 200U of the first cured layer 200.

[0016] The surface 200U, which serves as the polished surface, is a smooth plane when viewed macroscopically. However, when viewed microscopically, recesses 220 and 230 may be formed on the surface 200U. Some of the recesses 220 may be formed when some of the inorganic filler 10 particles 11 detach from the first hardened layer 200 due to the frictional force during polishing. In addition, generally, some of the inorganic filler 10 particles 12 may have voids 13 formed inside. When the inorganic filler 10 particles 12 having these voids 13 are polished, the voids 13 may open as the particles 12 are removed, and these voids 13 may form recesses 230. Conventionally, recesses 220 and 230 could be formed in this way due to the inorganic filler 10.

[0017] Therefore, the method for manufacturing a circuit board according to this embodiment further includes, in this order, the steps of: (IV) 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, as shown in Figure 4; (VI) curing the second resin composition layer 310 to form a second cured layer 300, as shown in Figure 5; and polishing the surface 300U of the second cured layer 300 opposite to the first cured layer 200, as shown in Figure 6.

[0018] By forming a second cured layer 300 on the surface 200U of the first cured layer 200 using the second resin composition 50, a cured product layer 400 containing the first cured layer 200 and the second cured layer 300 is obtained on the substrate 100. The recesses 220 and 230 that were on the surface 200U of the first cured layer 200 are filled by the second cured layer 300 and therefore do not appear on the surface 300U of the second cured layer 300. Furthermore, since the second cured layer 300 does not contain inorganic fillers, or has few large-particle inorganic filler particles in the second cured layer 300, and 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 can be manufactured that has a cured product layer 400 having a surface 300U as a polished surface in which the formation of recesses is suppressed.

[0019] <Step (I) to form the first resin composition layer> A method for manufacturing a circuit board according to one embodiment of the present invention includes a step (I) of forming a first resin composition layer with a first resin composition comprising 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." 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. Typically, this first resin composition layer contains only the first resin composition.

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

[0021] (A) As the material for the first inorganic filler, an inorganic compound is used. (A) Examples of materials for the 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 preferred, and silica is particularly preferred. Therefore, (A) the first inorganic filler preferably contains silica, and may contain only silica. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, hollow silica, etc. Furthermore, spherical silica is preferred as the silica. (A) The first inorganic filler may be used alone or in combination of two or more types.

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

[0023] (A) The 99% particle size of the first inorganic filler is preferably greater than 2 μm, more preferably 3 μm or more, even more preferably 4 μm or more, preferably 50 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less. (A) The 99% particle size of an inorganic filler such as the first inorganic filler refers to the particle size at which the cumulative volume from the smallest diameter side in the volume-based particle size distribution of the inorganic filler becomes 99%. (A) When the first inorganic filler has a 99% particle size within this range, the embedding properties when embedding the conductor layer and components in the first resin composition layer can be improved. Furthermore, while conventionally, when the 99% particle size of the first inorganic filler is large, recesses tend to form on the polished surface, the manufacturing method of the circuit board according to this embodiment can suppress the formation of such recesses on the polished surface of the cured 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, even more preferably 1 μm or more, preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less.

[0025] (A) The 99% particle size and average particle size of inorganic fillers such as the first inorganic filler can be measured by the laser diffraction-scattering method based on Mie scattering theory. Specifically, a volume-based particle size distribution of the inorganic filler is created using a laser diffraction-scattering particle size distribution analyzer. In this particle size distribution, the particle size at which the cumulative volume calculated from the smallest diameter side becomes 99% can be calculated as the 99% particle size. In addition, the median diameter of the above particle size distribution can be calculated as the average particle size. A sample can be used in which 100 mg of inorganic filler and 10 g of methyl ethyl ketone are weighed into a vial and dispersed using ultrasound for 10 minutes. The volume-based particle size distribution of the inorganic filler is measured using a flow cell method with a laser diffraction-type particle size distribution analyzer, using blue and red light source wavelengths. An example of a laser diffraction-type particle size distribution analyzer is the "LA-960" manufactured by Horiba, Ltd.

[0026] (A) The specific surface area of ​​the first inorganic filler is preferably 0.1 m². 2 / g or more, more preferably 0.5m 2 / g or more, more preferably 1m 2 / g or more, particularly preferably 3m 2 It is 100m or more / g, preferably 100m 2 / g or less, more preferably 70m 2 / g or less, more preferably 50m 2 / g or less, particularly preferably 40m 2 It is less than or equal to / g. (A) The specific surface area of ​​inorganic fillers such as the first inorganic filler can be measured by adsorbing nitrogen gas onto the sample surface using a specific surface area measuring device (Macsorb HM-1210 manufactured by Mountec Co., Ltd.) according to the BET method, and calculating the specific surface area using the BET multipoint 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 products of the surface treatment agent 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] From the viewpoint of improving the dispersibility of the (A) first inorganic filler, the degree of surface treatment with the surface treatment agent preferably falls within a specific range. Specifically, it is preferable that 100% by mass of the (A) first inorganic filler is surface-treated with 0.2% to 5% by mass of the surface treatment agent, more preferably 0.2% to 3% by mass of the surface treatment agent, and even more preferably 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 preferred, and 0.1 mg / m² 2 The above is more preferable, 0.2 mg / m² 2 The above is even more preferable. On the other hand, from the viewpoint of suppressing an increase in the melt viscosity of the first resin composition, 1.0 mg / m² 2 The following is preferred: 0.8 mg / m² 2 The following is more preferable: 0.5 mg / m² 2 The following are even more preferable.

[0031] (A) The amount of carbon per unit surface area of ​​an inorganic filler, such as the first inorganic filler, can be measured after the inorganic filler has been surface-treated and then washed with a solvent (e.g., methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as the solvent is added to the inorganic filler that has been surface-treated with a surface treatment agent, and then ultrasonically washed at 25°C for 5 minutes. After removing the supernatant and drying the solids, the amount of carbon per unit surface area of ​​the inorganic filler can be measured using a carbon analyzer. As a carbon analyzer, a Horiba "EMIA-320V" or similar can be used.

[0032] The amount of (A) first inorganic filler in the first resin composition is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, particularly preferably 80% by mass or more, preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less, based on 100% by mass of the nonvolatile components in the first resin composition. Unless otherwise specified, the nonvolatile components in the first resin composition refer to the components contained in the first resin composition excluding (H) solvent. When the amount of (A) first inorganic filler is within the above range, the elastic modulus, dielectric loss tangent, and linear thermal expansion coefficient of the first cured layer can be effectively improved. Furthermore, when using such a large amount of (A) first inorganic filler, conventionally there was a tendency for unintended depressions to easily form on the polished surface of the first cured layer. However, according to the manufacturing method of this embodiment, such depressions can be filled with the second cured layer, and a cured layer having a polished surface with suppressed depression formation can be obtained.

[0033] ((B) Explanation of the first curing resin) The (B) first curable resin, as component (B) in the first resin composition, is a curable resin, and may be a thermosetting resin, a photocurable resin, or a combination thereof. Furthermore, the (B) first curable resin may be used alone or in combination of two or more types. In particular, it is preferable that the (B) first curable resin contains a thermosetting resin. The (B) first curable resin may contain only a thermosetting resin.

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

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

[0036] Epoxy resin refers to a curable resin that contains epoxy groups. Examples of epoxy resins include bixylenol-type epoxy resin, 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 novolac-type epoxy resin, phenol novolac-type epoxy resin, tert-butyl-catechol-type epoxy resin, naphthalene-type epoxy resin, naphthol-type epoxy resin, anthracene-type epoxy resin, glycidylamine-type epoxy resin, glycidyl ester-type epoxy resin, cresol novolac-type epoxy resin, phenol aralkyl-type epoxy resin, biphenyl-type epoxy resin, linear aliphatic epoxy resin, epoxy resin having a butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, spiro-ring-containing epoxy resin, cyclohexane-type epoxy resin, cyclohexanedimethanol-type epoxy resin, naphthylene ether-type epoxy resin, trimethylol-type epoxy resin, tetraphenylethane-type epoxy resin, isocyanurate-type epoxy resin, and phenolphthaleimidine-type epoxy resin. Epoxy resin may be used individually or in combination of two or more types.

[0037] From the viewpoint of obtaining a cured product with excellent heat resistance, it is preferable that the epoxy resin contains an epoxy resin containing an aromatic structure. An aromatic structure is a chemical structure generally defined as aromatic, and includes polycyclic aromatics and aromatic heterocyclics. Examples of epoxy resins containing aromatic structures 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 novolac type epoxy resin, phenol novolac type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, bisquilenol type epoxy resin, glycidylamine type epoxy resin having an aromatic structure, glycidyl ester type epoxy resin having an aromatic structure, cresol novolac type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin having an aromatic structure, epoxy resin having a butadiene structure having 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, and tetraphenylethane type epoxy resin having an aromatic structure.

[0038] (B) The first curing resin preferably contains an epoxy resin having two or more epoxy groups in one molecule. The proportion of the epoxy resin having two or more epoxy groups in one molecule is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, relative to 100% by mass of the nonvolatile components of the total epoxy resin.

[0039] Epoxy resins include epoxy resins that are liquid at 20°C (hereinafter sometimes referred to as "liquid epoxy resins") and epoxy resins that are solid at 20°C (hereinafter sometimes referred to as "solid epoxy resins"). (B) The first curing 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] Preferred liquid epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidylamine 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.

[0042] Specific examples of liquid epoxy resins include: DIC Corporation's "HP-4032," "HP-4032-D," and "HP-4032-SS" (naphthalene-type epoxy resin); Mitsubishi Chemical Corporation's "828US," "828EL," "jER828EL," "825," and "Epicote 828EL" (bisphenol A-type epoxy resin); Mitsubishi Chemical Corporation's "jER807" and "1750" (bisphenol F-type epoxy resin); Mitsubishi Chemical Corporation's "jER152" (phenol novolac-type epoxy resin); Mitsubishi Chemical Corporation's "630," "630LSD," and "604" (glycidylamine-type epoxy resin); ADEKA Corporation's "ED-523T" (glycyrrhizol-type epoxy resin); and ADEKA Corporation's "EP-3950L" and "EP-3980." Examples include "S" (glycidylamine type epoxy resin); "EP-4088S" (dicyclopentadiene type epoxy resin) from ADEKA Corporation; "ZX1059" (a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin) from Nippon Steel Chemical & Material Co., Ltd.; "EX-721" (glycidyl ester type epoxy resin) from Nagase ChemteX Corporation; "Celoxide 2021P" (alicyclic epoxy resin with an ester skeleton) from Daicel Corporation; "PB-3600" from Daicel Corporation; "JP-100" and "JP-200" (epoxy resins with a butadiene structure) from Nippon Soda Co., Ltd.; and "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane type epoxy resin) from Nippon Steel Chemical & Material Co., Ltd. These can be used individually or in combination of two or more types.

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

[0044] Preferred solid epoxy resins include bixylenol-type epoxy resin, naphthalene-type epoxy resin, naphthalene-type tetrafunctional epoxy resin, naphthol novolac-type epoxy resin, cresol novolac-type epoxy resin, dicyclopentadiene-type epoxy resin, trisphenol-type epoxy resin, naphthol-type epoxy resin, biphenyl-type epoxy resin, naphthylene ether-type epoxy resin, anthracene-type epoxy resin, bisphenol A-type epoxy resin, bisphenol AF-type epoxy resin, phenol aralkyl-type epoxy resin, tetraphenylethane-type epoxy resin, and phenolphthaleimidine-type epoxy resin.

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

[0046] When using a combination of liquid epoxy resin and 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., even 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 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 even more preferably 400 to 1,500. The weight-average molecular weight can be measured as a polystyrene equivalent by gel permeation chromatography (GPC).

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

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

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

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

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

[0054] Specifically, preferred active ester resins include dicyclopentadiene-type active ester resins, naphthalene-type active ester resins containing a naphthalene structure, active ester resins containing an acetylated phenol novolac, and active ester resins containing a benzoylated phenol novolac, with dicyclopentadiene-type active ester resins being more preferred. Among these, active ester resins containing a dicyclopentadiene-type diphenol structure are preferred as dicyclopentadiene-type active ester resins.

[0055] Commercially available active ester resins include, for example, active ester resins containing a dicyclopentadiene-type diphenol structure such as "EXB9451", "EXB9460", "EXB9460S", "EXB-8000L", "EXB-8000L-65M", "EXB-8000L-65TM", "HPC-8000L-65TM", "HPC-8000", "HPC-8000-65T", "HPC-8000H", and "HPC-8000H-65TM" (manufactured by DIC Corporation); and active ester resins containing a naphthalene structure such as "HP-B-8151-62T", "EXB-8100L-65T", "EXB-8150-60T", and "EXB-815 Examples include "0-62T", "EXB-9416-70BK", "HPC-8150-60T", "HPC-8150-62T", and "EXB-8" (manufactured by DIC Corporation); as a phosphorus-containing active ester resin, "EXB9401" (manufactured by DIC Corporation); as an active ester resin that is an acetylated phenol novolac, "DC808" (manufactured by Mitsubishi Chemical Corporation); as an active ester resin that is a benzoylated phenol novolac, "YLH1026", "YLH1030", and "YLH1048" (manufactured by Mitsubishi Chemical Corporation); and as an active ester resin containing a styryl group and a naphthalene structure, "PC1300-02-65MA" (manufactured by Air Water Corporation).

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

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

[0058] As carbodiimide resins, resins having one or more, preferably two or more, carbodiimide structures in one molecule can be used. Specific examples of carbodiimide resins include aliphatic biscarbodiimides such as tetramethylene-bis(t-butylcarbodiimide) and cyclohexanebis(methylene-t-butylcarbodiimide); biscarbodiimides such as aromatic biscarbodiimides such as phenylene-bis(xylylcarbodiimide); aliphatic polycarbodiimides such as polyhexamethylenecarbodiimide, polytrimethylhexamethylenecarbodiimide, polycyclohexylenecarbodiimide, poly(methylenebiscyclohexylenecarbodiimide), and poly(isophoronecarbodiimide); and poly(phenylenecarbodiimide), poly(na Examples of polycarbodiimides include aromatic polycarbodiimides such as phthalenecarbodiimide, poly(tylenecarbodiimide), poly(methyldiisopropylphenylenecarbodiimide), poly(triethylphenylenecarbodiimide), poly(diethylphenylenecarbodiimide), poly(triisopropylphenylenecarbodiimide), poly(diisopropylphenylenecarbodiimide), poly(xylylenecarbodiimide), poly(tetramethylxylylenecarbodiimide), poly(methylenediphenylenecarbodiimide), and poly[methylenebis(methylphenylene)carbodiimide]. Examples of commercially available carbodiimide resins include "Carbodilite V-02B," "Carbodilite V-03," "Carbodilite V-04K," "Carbodilite V-05," "Carbodilite V-07," and "Carbodilite V-09" from Nisshinbo Chemical Co., Ltd., and "Stavaxol P," "Stavaxol P400," and "Hycazil 510" from Lanxess Corporation.

[0059] As acid anhydride resins, resins having one or more, preferably two or more acid anhydride groups in one molecule can be used. Specific examples of acid anhydride resins 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-cyclohexen-1,2-dicarboxylic acid anhydride, trimellitic anhydride, pyromellitic anhydride, and bensophenone tetracarboxylic acid di Examples include anhydrides, biphenyltetracarboxylic acid dianhydride, naphthalenetetracarboxylic acid dianhydride, oxydiphthalic acid dianhydride, 3,3'-4,4'-diphenylsulfonetetracarboxylic acid 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 styrene-maleic acid resin obtained by copolymerizing styrene and maleic acid. Examples of commercially available acid anhydride resins include "HNA-100," "MH-700," "MTA-15," "DDSA," and "OSA" from Shin Nippon Rika Co., Ltd.; "YH-306" and "YH-307" from Mitsubishi Chemical Corporation; "HN-2200" and "HN-5500" from Resona Corporation; and "EF-30," "EF-40," "EF-60," and "EF-80" from Clay Valley Corporation.

[0060] As the benzoxazine resin, a resin having one or more, preferably two or more, benzoxazine rings in one molecule can be used. Specific examples of benzoxazine resins include "JBZ-OP100D" and "ODA-BOZ" from JFE Chemical Corporation; "HFB2006M" from Showa Polymer Co., Ltd.; and "Pd" and "Fa" from Shikoku Chemicals Co., Ltd.

[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 cyanate ester resins 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'-ethylidene diphenyl 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 novolacs and cresol novolacs; and prepolymers in which these cyanate ester resins are partially triazined. Specific examples of cyanate ester resins include "PT30" and "PT60" (phenol novolac type polyfunctional cyanate ester resins) manufactured by Lonza, as well as "BA230" and "BA230S75" (prepolymers in which part or all of bisphenol A dicyanate is triazined and trimerized).

[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 amine resins include aliphatic amines, polyetheramines, alicyclic amines, aromatic amines, etc., with aromatic amines being preferred. The amine resin is preferably a primary amine or a secondary amine, with primary amines being more preferred. Specific examples of amine resins 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, and 2,2-bis(3-amino-4-hydroxyphenyl)propyl Examples include pan, 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. Examples of commercially available amine resins include "SEIKACURE-S" from Seika Corporation; "KAYABOND C-200S," "KAYABOND C-100," "KAYAHARD AA," "KAYAHARD AB," and "KAYAHARD AS" from Nippon Kayaku Co., Ltd.; "Epicure W" from Mitsubishi Chemical Corporation; and "DTDA" from Sumitomo Seika Co., Ltd.

[0063] Examples of thiol-based resins include trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), and tris(3-mercaptopropyl) isocyanurate.

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

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

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

[0067] The amount of curing agent in the first resin composition is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, preferably 80% by mass or less, more preferably 70% by mass or less, and even 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 epoxy resin and a curing agent, the range of the number of active groups of the curing agent relative to the number of epoxy groups of the epoxy resin is preferably 0.1 or more, more preferably 0.3 or more, even more preferably 0.5 or more, 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 refers to the sum of all 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. The "number of active groups of the curing agent" in the first resin composition refers to the sum of all 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.

[0069] As radical polymerizable resins, resins containing ethylenically unsaturated bonds can be used. Therefore, radical polymerizable resins can usually have radical polymerizable groups containing ethylenically unsaturated bonds. Examples of radical polymerizable groups include unsaturated hydrocarbon groups such as vinyl groups, allyl groups, 1-propenyl groups, 3-cyclohexenyl groups, 3-cyclopentenyl groups, 2-vinylphenyl groups, 3-vinylphenyl groups, and 4-vinylphenyl groups; and α,β-unsaturated carbonyl groups such as acryloyl groups, methacryloyl groups, and maleimide groups (2,5-dihydro-2,5-dioxo-1H-pyrrole-1-yl groups). It is preferable for radical polymerizable resins to have two or more radical polymerizable groups.

[0070] Examples of radical polymerizable resins include (meth)acrylic radical polymerizable resins, styrene radical polymerizable resins, allyl radical polymerizable resins, and maleimide radical polymerizable resins. Radical polymerizable resins may be used individually or in combination of two or more types.

[0071] As (meth)acrylic radical polymerizable resins, resins having one or more, preferably two or more acryloyl groups and / or methacryloyl groups per molecule can be used. Examples of (meth)acrylic radical polymerizable resins include 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, and 1,9-nonane. Low molecular weight (molecular weight less than 1000) aliphatic (meth)acrylic acid ester compounds such as diol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, glycerin tri(meth)acrylate, and pentaerythritol tetra(meth)acrylate; dioxaneglycol di(meth)acrylate, 3,6-dioxa-1,8-octanediol di(meth)acrylate; Examples include low molecular weight (molecular weight less than 1000) ether-containing (meth)acrylic acid ester compounds such as 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, and propoxylated bisphenol A di(meth)acrylate; low molecular weight (molecular weight less than 1000) isocyanurate-containing (meth)acrylic acid ester compounds such as tris(3-hydroxypropyl) isocyanurate tri(meth)acrylate, tris(2-hydroxyethyl) isocyanurate tri(meth)acrylate, and ethoxylated isocyanurate tri(meth)acrylate; and high molecular weight (molecular weight 1000 or more) acrylic acid ester compounds such as (meth)acrylic-modified polyphenylene ether resins.Examples of commercially available (meth)acrylic radical polymerizable resins include "A-DOG" (dioxane glycol diacrylate) from Shin Nakamura Chemical Industry Co., Ltd., "DCP-A" (tricyclodecane dimethanol diacrylate), "DCP" (tricyclodecane dimethanol dimethacrylate), and "BPE-1300N" (ethoxylated bisphenol A dimethacrylate) from Kyoeisha Chemical Co., Ltd., "KAYARAD R-684" (tricyclodecane dimethanol diacrylate) and "KAYARAD R-604" (dioxane glycol diacrylate) from Nippon Kayaku Co., Ltd., and "SA9000" and "SA9000-111" (methacrylic modified polyphenylene ether) from SABIC Corporation.

[0072] As styrene-based radical polymerizable resins, resins having one or more, preferably two or more, vinyl groups directly bonded to aromatic carbon atoms in one molecule can be used. Examples of styrene-based radical polymerizable resins include low molecular weight (molecular weight less than 1000) styrene 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, and bis(4-vinylphenyl) ether; and high molecular weight (molecular weight 1000 or more) styrene compounds such as vinylbenzyl-modified polyphenylene ether resins and styrene-divinylbenzene copolymers. Examples of commercially available styrene-based radical polymerizable resins include "ODV-XET(X03)", "ODV-XET(X04)", and "ODV-XET(X05)" (styrene-divinylbenzene copolymer) from Nippon Steel Chemical & Material Co., Ltd., and "OPE-2St 1200" and "OPE-2St 2200" (vinylbenzyl-modified polyphenylene ether resin) from Mitsubishi Gas Chemical Co., Ltd.

[0073] As the allyl-based radical polymerizable resin, a resin having one or more, preferably two or more allyl groups per molecule can be used. Examples of allyl-based radical polymerizable resins include aromatic carboxylic acid allyl ester compounds such as diallyl diphenate, triallyl trimellitate, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, diallyl 2,6-naphthalenedicarboxylic acid, and diallyl 2,3-naphthalenecarboxylic acid; isocyanuric acid allyl ester compounds such as 1,3,5-trialyl 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-benzoxazine-3-yl)phenyl]methane; ether-containing aromatic allyl compounds such as 1,3,5-trialyl etherbenzene; and allyl silane compounds such as diallyldiphenylsilane. Examples of commercially available allyl-based radical polymerizable resins include "TAIC" (1,3,5-triallyl isocyanurate) from Nippon Chemical Industries, Ltd., "DAD" (diallyl diphenate) from Nichishoku Techno Fine Chemicals Co., Ltd., "TRIAM-705" (triallyl trimellitate) from Fujifilm Wako Pure Chemical Corporation, "DAND" (2,3-naphthalenecarboxylate diallyl) from Nichishoku Techno Fine Chemicals Co., Ltd., "ALP-d" (bis[3-allyl-4-(3,4-dihydro-2H-1,3-benzoxazine-3-yl)phenyl]methane) from Shikoku Chemicals, Ltd., "RE-810NM" (2,2-bis[3-allyl-4-(glycidyloxy)phenyl]propane) from Nippon Kayaku Co., Ltd., and "DA-MGIC" (1,3-diallyl-5-glycidyl isocyanurate) from Shikoku Chemicals, Ltd.

[0074] As the maleimide-based radical polymerizable resin, a resin having one or more, preferably two or more, maleimide groups per molecule can be used. The maleimide-based radical polymerizable resin may be an aromatic maleimide resin having maleimide groups directly bonded to an aromatic ring, or it may be an aliphatic maleimide resin not having maleimide groups directly bonded to an aromatic ring. Examples of commercially available maleimide-based radical polymerizable resins include "SLK-2600" from Shin-Etsu Chemical Co., Ltd., "BMI-1500", "BMI-1700", "BMI-3000J", "BMI-689", and "BMI-2500" (maleimide compounds containing dimer amine structure) from Designer Molecules Inc., "BMI-6100" (aromatic maleimide compound) from Designer Molecules Inc., "MIR-5000-60T" and "MIR-3000-70MT" (biphenyl aralkyl type maleimide compounds) from Nippon Kayaku Co., Ltd., "BMI-70" and "BMI-80" from K.I. Chemicals Co., Ltd., and "BMI-2300" and "BMI-TMH" from Yamato Chemical Industries, Ltd. Furthermore, as a maleimide-based radical polymerizable resin, a maleimide resin (indane ring skeleton-containing maleimide compound) disclosed in the Japan Institute of Invention and Innovation Publication No. 2020-500211 may be used.

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

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

[0077] The amount of radical polymerizable resin in the first resin composition is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 1% by mass or more, preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, based on 100% by mass of the nonvolatile components in the first resin composition.

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

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

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

[0081] The total amount of (A) the first inorganic filler and (B) the first curable resin in the first resin composition is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, based on 100% by mass of the nonvolatile 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] ((C) Explanation of polymer resins) The first resin composition may contain (C) polymer resin as an optional component. The (C) polymer resin is usually thermoplastic and is included in the first resin composition in a state of compatibility with resin components other than the (C) polymer resin. The (C) polymer resin as component (C) does not include those corresponding to components (A) to (B) described above. Furthermore, one type of (C) polymer resin may be used alone, or two or more types may be used in combination.

[0083] (C) Examples of polymer resins 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, etc.

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

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

[0086] Specific examples of polyimide resins include "SLK-6100" manufactured by Shin-Etsu Chemical Co., Ltd., and "Ricacoat SN20" and "Ricacoat PN20" manufactured by Shin-Nippon Rika Co., Ltd. Other specific examples of polyimide resins include linear polyimides obtained by reacting a bifunctional hydroxyl-terminated polybutadiene, a diisocyanate compound, and a tetrabasic acid anhydride (polyimides described in Japanese Patent Publication No. 2006-37083), and modified polyimides containing a polysiloxane skeleton (polyimides described in Japanese Patent Publication No. 2002-12667 and Japanese Patent Publication No. 2000-319386, etc.).

[0087] Examples of polyvinyl acetal resins include polyvinyl formal resin and polyvinyl butyral resin, with polyvinyl butyral resin being preferred. Specific examples of polyvinyl acetal resins include S-Rec BH series, BX series (e.g., BX-5Z), KS series (e.g., KS-1), BL series, BM series, etc., manufactured by Sekisui Chemical Co., Ltd.

[0088] Examples of polyolefin resins 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 polybutadiene resins include hydrogenated polybutadiene skeleton-containing resins, hydroxyl group-containing polybutadiene resins, phenolic hydroxyl group-containing polybutadiene resins, carboxyl group-containing polybutadiene resins, acid anhydride group-containing polybutadiene resins, epoxy group-containing polybutadiene resins, isocyanate group-containing polybutadiene resins, urethane group-containing polybutadiene resins, and polyphenylene ether-polybutadiene resins. Part or all of the polybutadiene structure of the polybutadiene resin may be hydrogenated. Specific examples of polybutadiene resins include Clay Valley's "Ricon 130MA8," "Ricon 130MA13," "Ricon 130MA20," "Ricon 131MA5," "Ricon 131MA10," "Ricon 131MA17," "Ricon 131MA20," and "Ricon 184MA6" (polybutadiene containing acid anhydride groups); Nippon Soda's "GQ-1000" (polybutadiene with hydroxyl and carboxyl groups), "G-1000," "G-2000," and "G-3000" (polybutadiene with hydroxyl groups at both ends), "GI-1000," "GI-2000," and "GI-3000" (hydrogenated polybutadiene with hydroxyl groups at both ends); and Nagase ChemteX's "FCA-061L" (hydrogenated polybutadiene skeleton epoxy resin). Furthermore, specific examples of polybutadiene resins include polyimide resins having polybutadiene structures, urethane structures, and imide structures within the molecule. These polyimide resins can be produced as linear polyimide resins (polyimides described in Japanese Patent Publication No. 2006-37083 and International Publication No. 2008 / 153208) using hydroxyl-terminated polybutadiene, diisocyanate compounds, and tetrabasic acid anhydrides as raw materials. The butadiene structure content of these polyimide resins is preferably 60% to 95% by mass, more preferably 75% to 85% by mass. Details of these polyimide resins can be found in Japanese Patent Publication No. 2006-37083 and International Publication No. 2008 / 153208, and this information is incorporated herein by reference.

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

[0091] Specific examples of polyetherimide resins include GE's "Ultem," among others.

[0092] Specific examples of polysulfone resins include Solvay Advanced Polymers' polysulfones "P1700" and "P3500".

[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 "OPE-2St 1200," an oligophenylene ether / styrene resin manufactured by Mitsubishi Gas Chemical Company.

[0095] Examples of polycarbonate resins include hydroxyl group-containing carbonate resins, phenolic hydroxyl group-containing carbonate resins, carboxyl group-containing carbonate resins, acid anhydride group-containing carbonate resins, isocyanate group-containing carbonate resins, and urethane group-containing carbonate resins. Specific examples of polycarbonate resins include "FPC0220" from Mitsubishi Gas Chemical Co., Ltd., "T6002" and "T6001" (polycarbonate diols) from Asahi Kasei Corporation, and "C-1090," "C-2090," and "C-3090" (polycarbonate diols) from Kuraray Co., Ltd. Furthermore, specific examples of polycarbonate resins include polyimide resins having imide, urethane, and polycarbonate structures within the molecule. These polyimide resins can be produced as linear polyimide resins using hydroxyl group-terminated polycarbonates, diisocyanate compounds, and tetrabasic acid anhydrides as raw materials. The content of the carbonate structure in the polyimide resin is preferably 60% to 95% by mass, more preferably 75% to 85% by mass. Details of the polyimide resin can be found in International Publication No. 2016 / 129541, which is incorporated herein by reference.

[0096] Specific examples of polyether ether ketone resins include "Sumiproi K" manufactured by Sumitomo Chemical Co., Ltd.

[0097] Examples of polyester resins include polyethylene terephthalate resin, polyethylene naphthalate resin, polybutylene terephthalate resin, polybutylene naphthalate resin, polytrimethylene terephthalate resin, polytrimethylene naphthalate resin, and polycyclohexanedimethyl terephthalate resin.

[0098] (C) Polymer resins typically have a large molecular weight. Specifically, the weight-average molecular weight Mw of (C) polymer resins is preferably greater than 5,000, more preferably 8,000 or more, even more preferably 10,000 or more, even more preferably 20,000 or more, preferably 100,000 or less, more preferably 70,000 or less, even more preferably 60,000 or less, and even more preferably 50,000 or less. The weight-average molecular weight Mw can be measured in polystyrene equivalent values ​​by gel permeation chromatography (GPC).

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

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

[0101] ((D) Explanation of curing accelerator) The first resin composition may contain (D) a curing accelerator as an optional component. The (D) curing accelerator can act as a catalyst in the reaction of (B) the first curable resin, thereby accelerating the curing of the first resin composition. The (D) curing accelerator as component (D) does not include components (A) to (C) described above. Furthermore, one type of (D) curing accelerator may be used alone, or two or more types may be used in combination.

[0102] (D) As a curing accelerator, an appropriate one may be used depending on the type of (B) primary curing resin. For example, if (B) primary curing resin contains epoxy resin, (D) curing accelerators that can accelerate the curing of the epoxy resin include, for example, phosphorus-based curing accelerators, urea-based curing accelerators, guanidine-based curing accelerators, imidazole-based curing accelerators, metal-based curing accelerators, amine-based curing accelerators, etc.

[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) pyromelitate, tetrabutylphosphonium hydrogen hexahydrophthalate, tetrabutylphosphonium 2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenolate, and di-tert-butyldimethylphosphonium tetraphenylborate; methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, propyltriphenylphosphonium bromide, butyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, tetraphenylphosphonium bromide, p-tolyltriphenylphosphonium tetra-p-tolylborate, and tetraphenylphosphonium bromide. Aromatic phosphonium salts such as tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, triphenylethylphosphonium tetraphenylborate, tris(3-methylphenyl)ethylphosphonium tetraphenylborate, tris(2-methoxyphenyl)ethylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate; aromatic phosphine-borane complexes such as triphenylphosphine-triphenylborane; aromatic phosphine-quinone addition products such as triphenylphosphine-p-benzoquinone addition products; aliphatic phosphines such as tributylphosphine, tri-tert-butylphosphine, trioctylphosphine, di-tert-butyl(2-butenyl)phosphine, di-tert-butyl(3-methyl-2-butenyl)phosphine, and tricyclohexylphosphine;Dibutylphenylphosphine, di-tert-butylphenylphosphine, methyldiphenylphosphine, ethyldiphenylphosphine, butyldiphenylphosphine, diphenylcyclohexylphosphine, triphenylphosphine, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tris(4-ethylphenyl)phosphine, tris(4-propylphenyl)phosphine, tris(4-isopropylphenyl)phosphine, tris(4-butylphenyl)phosphine, tris(4-tert-butylphenyl)phosphine, tris(2,4-dimethylphenyl)phosphine, tris(2,5-dimethylphenyl)phosphine, tris(2,6-dimethylphenyl)phosphine Examples include aromatic phosphines such as 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, and 2,2'-bis(diphenylphosphino)diphenyl ether.

[0104] Examples of 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, and 3-cyclooctyl-1,1-dimethylurea; 3-phenyl-1,1-dimethylurea, 3-(4-chlorophenyl)-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea, 3-(2-methylphenyl)-1,1-dimethylurea, 3-(4-methylphenyl)-1,1-dimethylurea, and 3-(3,4-dimethylphenyl)-1,1-dimethylurea. Aromatic dimethylureas such as toluenebisdimethylurea, 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), and N,N-(4-methyl-1,3-phenylene)bis(N',N'-dimethylurea) [toluenebisdimethylurea] are examples.

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

[0106] Examples of imidazole-based curing accelerators include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 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 isocyanurate adduct, 2-phenylimidazole isocyanurate adduct Examples of imidazole compounds include 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, and 2-phenylimidazoline, as well as adducts of imidazole compounds with epoxy resins. Examples of commercially available imidazole-based curing accelerators include "1B2PZ", "2E4MZ", "2MZA-PW", "2MZ-OK", "2MA-OK", "2MA-OK-PW", "2PHZ", "2PHZ-PW", "Cl1Z", "Cl1Z-CN", "Cl1Z-CNS", and "C11Z-A" from Shikoku Chemicals, Inc., and "P200-H50" from Mitsubishi Chemical Corporation.

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

[0108] Examples of amine-based curing accelerators include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene. Commercially available amine-based curing accelerators may also be used, such as "MY-25" manufactured by Ajinomoto Fine Techno Co., Ltd.

[0109] The amount of (D) curing accelerator in the first resin composition is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, even more preferably 0.02% by mass or more, preferably 2% by mass or less, more preferably 1% by mass or less, and even more preferably 0.5% by mass or less, based on 100% by mass of the nonvolatile components in the first resin composition.

[0110] The amount of (D) curing accelerator in the first resin composition is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 5% by mass or less, based on 100% by mass of the resin component in the first resin composition.

[0111] ((E) Explanation of adhesion aids) The first resin composition may contain (E) an adhesion aid as an optional component. The adhesion aid (E) can increase the adhesion strength between the cured layer and the layer in contact with the cured layer. The adhesion aid (E) as component (E) does not include components (A) to (D) described above. Furthermore, one type of adhesion aid (E) may be used alone, or two or more types may be used in combination.

[0112] (E) Examples of adhesion aids include 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]phthalamidic acid, benzophenone-3,3'-bis(N-[3-triethoxysilyl]propylamide)-4,4'-dicarboxylic acid, benzene-1,4-bis(N-3-triethoxysilyl]propylamide)-2,5-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-mercap Silane coupling agents such as toethyltrimethoxysilane, 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; and aluminum-based adhesive aids such as aluminum tris(ethylacetate), aluminum tris(acetylacetonate), and ethylacetate aluminum diisopropylate. Among them, (E) silane coupling agents are preferred as adhesion enhancers.

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

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

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

[0116] ((F) Explanation of flame retardants) The first resin composition may contain (F) a flame retardant as an optional component. The flame retardant (F) can improve the flame retardancy of the cured layer. The flame retardant (F) as component (F) does not include components (A) to (E). Furthermore, one type of flame retardant (F) may be used alone, or two or more types may be used in combination.

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

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

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

[0120] (G) Description of any additives) The first resin composition may further contain (G) any additives as optional components. (G) Any additives as components (G) do not include those corresponding to components (A) to (F) described above. (G) Any additives include, for example, radical polymerization initiators such as peroxide-based radical polymerization initiators and azo-based radical polymerization initiators; organometallic compounds such as organocopper compounds, organozinc compounds, and organocobalt compounds; colorants such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium dioxide, 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 bentonite and montmorillonite; silicone-based defoamers, acrylic-based defoamers, and fluorine-based defoamers. Examples of additives include: defoamers such as defoaming agents and vinyl resin-based defoamers; ultraviolet absorbers such as benzotriazole-based ultraviolet absorbers; adhesion enhancers such as urea silane; antioxidants such as hindered phenol-based antioxidants; fluorescent whitening agents 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; and stabilizers such as borate-based stabilizers, titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, and carboxylic acid anhydride-based stabilizers. (G) Any additive may be used alone or in combination of two or more types.

[0121] ((H) Explanation of solvents) The first resin composition may further contain a solvent (H) as an optional volatile component in combination with the non-volatile components such as components (A) to (G) described above. Typically, an organic solvent is used as the solvent (H). Examples of organic solvents 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; 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl diglycol acetate, γ-butyrolactone, and methyl methoxypropionate. Examples include ether ester solvents such as tyl; 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; and aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene. (H) The solvent may be used alone or in combination of two or more types.

[0122] The amount of (H) solvent in the first resin composition forming the first resin composition layer is preferably small. The amount of (H) solvent in the first resin composition is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 4% by mass or less, even more preferably 3% by mass or less, and even 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 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 upon curing. Hereinafter, the cured product of the first resin composition may be referred to as the "first cured product." This first cured product forms the first cured layer. During curing, heat is usually applied to the first resin composition, so among the components contained in the first resin composition, the (H) solvent, which is a volatile component, may volatilize due to the heat during curing. Therefore, the first cured product may contain non-volatile components of the first resin composition or their reaction products.

[0124] The first cured product can usually have a high modulus of elasticity G1. The range of the modulus of elasticity G1 of the first cured product is preferably 10 GPa or more, more preferably 12 GPa or more, even more preferably 14 GPa or more, preferably 40 GPa or less, more preferably 30 GPa or less, and even more preferably 20 GPa or less. When the first cured product has such a high modulus of elasticity G1, warping of the circuit board and intermediate products during its manufacturing can be effectively suppressed, and the manufacturing of the circuit board can be carried out smoothly. In addition, the formation of polishing marks on the first cured layer can usually be suppressed, and resin clogging of the polishing equipment can be suppressed, so the polishing of the first cured layer can be carried out smoothly.

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

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

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

[0128] (Explanation of the manufacturing method of the first resin composition) The first resin composition can be manufactured by mixing components that may be included in the first resin composition. The above-mentioned components may be mixed some or all at the same time, or they may be mixed sequentially. The temperature may be set appropriately during the mixing of each component, and thus heating and / or cooling may be performed temporarily or throughout the process. Furthermore, stirring or shaking may be performed during the mixing of 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 substrate, which is an example of a substrate. The "inner layer substrate" is a material that serves as the substrate for a circuit board, and examples include glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, thermosetting polyphenylene ether substrates, etc. The inner layer substrate may also have a conductive layer on one or both sides. The conductive layer on the inner layer substrate may also be patterned. An inner layer substrate in which a conductive layer (circuit) is formed on one or both sides of the substrate is sometimes called an "inner layer circuit substrate." Furthermore, an intermediate product on which an insulating layer and / or a conductive layer is to be further formed when manufacturing a circuit board is also included in the term "inner layer substrate." In addition, an inner layer substrate equipped with components such as semiconductor chips may be used.

[0130] Furthermore, in step (I), a first resin composition layer may be formed on a temporary substrate as an example of a substrate. Specifically, a component may be temporarily fixed on a removable temporary substrate, and the first resin composition layer may be formed to embed the component. In this case, after curing the first resin composition layer in step (II) described later to form a first cured layer, the temporary substrate can be removed to obtain a first cured layer with the component embedded inside. Such a removable temporary substrate can be manufactured, for example, by laminating a substrate and a temporary fixing film. Examples of substrates include silicon wafers, glass wafers, glass substrates, metal substrates such as copper, titanium, stainless steel, and cold-rolled steel sheets (SPCC); substrates such as FR-4 substrates, which are glass fibers impregnated with epoxy resin and heat-cured; and substrates made of bismaleimide triazine resin such as BT resin. In addition, the temporary fixing film can be a film that can be peeled off from the component and can temporarily fix the component, for example, "Riva Alpha" 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 typically involves placing the substrate and the first resin composition in a mold and applying pressure and, if necessary, heat to the first resin composition within the mold to form the first resin composition layer on the substrate.

[0132] The compression molding method may be carried out, for example, as follows: An upper mold and a lower mold are prepared as molds for compression molding. The first resin composition is applied to the substrate. The substrate coated with the first resin composition is attached to the lower mold. Then, the upper and lower molds are clamped together, and heat and pressure are applied to the first resin composition to perform compression molding.

[0133] Furthermore, the compression molding method may be carried out as follows, for example: An upper mold and a lower mold are prepared as molds for compression molding. The first resin composition is placed on the lower mold. The base material is attached to the upper mold. Then, the upper and lower molds are clamped together so that the first resin composition on the lower mold is in contact with the base material attached to the upper mold, and heat and pressure are applied to perform compression molding.

[0134] Furthermore, the compression molding method may involve, for example, discharging the first resin composition filled in a cartridge into a mold, and then applying heat and pressure within the mold to perform compression molding.

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

[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 represents a sheet comprising a support and a first resin composition layer formed on the support. The first resin composition layer can be formed on the substrate by laminating the resin sheet and the substrate so that the first resin composition layer and the substrate are bonded together. The first resin composition layer provided on the resin sheet usually has the same thickness as the first resin composition layer that would be formed on the substrate.

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

[0138] When using a plastic film as a support, examples of plastic materials include polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter sometimes abbreviated as "PEN"), polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylics such as polymethyl methacrylate (PMMA), cyclic polyolefins, triacetylcellulose (TAC), polyether sulfide (PES), polyether ketones, and polyimides. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred, and inexpensive polyethylene terephthalate is particularly preferred.

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

[0140] The support may have surface treatments such as matte finish, corona treatment, or antistatic treatment applied to the surface that bonds with the first resin composition layer.

[0141] As the support, a support with a release layer may be used, which has a release layer on the surface that is bonded to the first resin composition layer. Examples of release agents used in the release layer of the support with a release layer include one or more release agents selected from the group consisting of alkyd-based release agents, polyolefin-based release agents, urethane-based release agents, and silicone-based release agents. Commercially available products may be used as the support with a release layer, for example, PET films having a release layer mainly composed of a silicone-based release agent or an alkyd resin-based release agent, such as "PET501010", "SK-1", "AL-5", and "AL-7" from Lintec Corporation; "Lumirror T60" from Toray Industries, Inc.; "Purex" from Teijin Corporation; and "Unipeel" from Unitika Corporation.

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

[0143] The resin sheet may include any components as needed. For example, the resin sheet may include a protective film to protect the first resin composition layer. The protective film is usually provided on the side of the first resin composition layer that is not bonded to the support (i.e., the side opposite to the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. When a protective film is provided, the 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 the protective film has been removed.

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

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

[0146] One method for laminating a resin sheet and a substrate is to heat-press the resin sheet onto the substrate from the support side. Examples of the member used to heat-press the resin sheet onto the substrate (hereinafter also referred to as the "heat-pressing member") include a heated metal plate (such as a SUS end plate) or a metal roll (such as a SUS roll). It is preferable to press the resin sheet with the heat-pressing member via an elastic material such as heat-resistant rubber, rather than pressing the resin sheet directly onto the substrate, so that the resin sheet can adequately follow the surface irregularities of the substrate.

[0147] Lamination of the substrate and resin sheet may be carried out by vacuum lamination. In vacuum lamination, the lamination conditions may be as follows: The heat-pressing 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-pressing 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-pressing time is preferably in the range of 20 seconds to 400 seconds, more preferably in the range of 30 seconds to 300 seconds. Lamination is preferably carried out under reduced pressure conditions of 26.7 hPa or less.

[0148] Lamination can be performed using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include vacuum pressure laminators manufactured by Meiki Seisakusho Co., Ltd., vacuum applicators manufactured by Nikko Materials Co., Ltd., and batch-type vacuum pressure laminators.

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

[0150] If a first resin composition layer is formed on a substrate using a 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 after step (II).

[0151] The formation of the first resin composition layer in step (I) may be carried out by a method including, for example, the application of the first resin composition. For example, the liquid first resin composition may be applied to a substrate and then dried as necessary to form the first resin composition layer. Another example is to prepare a liquid first resin composition by mixing a solvent and the first resin composition, apply this to a substrate, and then dry it to form the first resin composition layer. The solvent may be the same as the solvent (H) described as a component of the first resin composition. Furthermore, 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. In this case, 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, the die coating method is preferred.

[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 even more preferably 150 μm or more. If the thickness of the first resin composition layer is greater than or equal to the lower limit, the first cured layer before polishing can be made thicker, so that a first cured layer with 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 may be, for example, 500 μm or less, 400 μm or less, 300 μm or less, etc.

[0153] <Step (II) to cure the first resin composition layer> A method for manufacturing a circuit board according to one embodiment of the present invention includes, after step (I), step (II) of curing a 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 depending on the type of (B) first curable resin. For example, if (B) the first curable resin contains a thermosetting resin, the first resin composition layer may be cured by heating. Alternatively, for example, if (B) the first curable resin contains a photocurable resin, the first resin composition layer may be cured by light irradiation. In a preferred embodiment, since (B) the first curable resin contains a thermosetting resin, step (II) is to cure the first resin composition layer by heating.

[0155] The specific curing temperature of the first resin composition layer is, in one example, preferably 120°C to 240°C, more preferably 150°C to 220°C, and even more preferably 170°C to 210°C. The curing time is, in one example, 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. Preheating may be carried out, for example, at a temperature of typically 50°C to 150°C, preferably 60°C to 140°C, more preferably 70°C to 130°C, for a processing time of typically 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.

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

[0158] Furthermore, the first cured layer typically has a dielectric loss tangent in the same range as the dielectric loss tangent of the first cured product described above. In addition, the first cured layer typically has the same thickness as the first resin composition layer before curing.

[0159] <Step (III) of polishing the first hardened layer> A method for manufacturing a circuit board according to one embodiment of the present invention includes a step (III) of polishing the surface of the first hardened layer after step (II). When the first hardened layer is formed on a substrate, the surface of the first hardened layer opposite to the substrate is usually polished. Polishing creates a smooth polished surface on the surface of the first hardened layer. Polishing also reduces the thickness of the first hardened layer. Furthermore, as described above, polishing can create recesses on the polished surface.

[0160] The polished surface formed on the surface of the first hardened layer by polishing usually has a low surface roughness. For example, the arithmetic mean roughness of the polished surface of the first hardened layer is preferably 500 nm or less, more preferably 300 nm or less, and particularly preferably 100 nm or less. There is no particular lower limit, and it may be, for example, 10 nm or more, 20 nm or more, 50 nm or more, etc. However, this arithmetic mean roughness represents the value in areas without depressions. The arithmetic mean roughness can be measured using a non-contact surface roughness meter (WYKO NT3300, manufactured by Bee Instruments) in VSI mode with a 50x lens.

[0161] On the polished surface of the first hardened layer, recesses are typically formed, usually due to the (A) first inorganic filler contained in the first resin composition. 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 a single (A) first inorganic filler particle may be the same as or close to the diameter of that single particle. Also, for example, the opening diameter of a recess formed by the opening of a void formed within a particle of (A) first inorganic filler through polishing may be smaller than the diameter of that single particle. Furthermore, for example, the opening diameter of a recess formed by the detachment of multiple particles of (A) first inorganic filler as a clump may be larger than the diameter of that single particle. The specific opening diameter of the recess may vary depending on the particle size, amount, degree of dispersion, and void size of the (A) first inorganic filler. In one example, the lower limit of the recess opening diameter may be, for example, 1 μm or more, 2 μm or more, 3 μm or more, etc. Furthermore, the upper limit could be, for example, 50 μm or less, 40 μm or less, or 30 μm or less.

[0162] Polishing reduces the thickness of the first hardened layer. At this time, the amount of thickness reduction is equal to the thickness of the first hardened layer before polishing (T1). b And, the thickness T1 of the first hardened layer after polishing a Difference T1 b -T1 a This is represented by: The amount of reduction in the thickness of the first hardened layer due to polishing T1 b -T1 a This 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 hardened layer is significantly reduced, (A) recesses caused by the first inorganic filler tend to form easily. Therefore, from the viewpoint of utilizing the advantage of this embodiment, which is that the problems caused by these recesses can be resolved, the amount of reduction in the thickness of the first hardened layer due to polishing T1 b -T1 a It is preferable that it is within the above range. The amount of reduction in the thickness of the first hardened layer due to polishing T1 b -T1 a The upper limit is the thickness T1 of the first hardened layer before polishing. b It can be a smaller value, such as 300 μm or less, 200 μm or less, or 100 μm or less.

[0163] Thickness T1 of the first hardened layer after polishing a This can be set according to the circuit board design. Specific thickness T1 of the first hardened layer after polishing. a In one example, the range is preferably 20 μm or more, more preferably 50 μm or more, even more preferably 100 μm or more, even more preferably 120 μm or more, preferably 400 μm or less, more preferably 300 μm or less, and even more preferably 200 μm or less.

[0164] Methods for polishing the first hardened layer include, for example, chemical mechanical polishing using a chemical mechanical polishing apparatus; mechanical polishing methods such as belt polishing, buff polishing, ceramic polishing, grinding using a surface grinding machine, and surface grinding using a rotating grinding wheel. Depending on the desired condition of the polished surface, abrasive grains of various grits may be used.

[0165] <Step (IV) to form the second resin composition layer> A method for manufacturing a circuit board according to one embodiment of the present invention includes, after step (III), step (IV), forming a second resin composition layer on the polished surface of the first cured layer (i.e., the polished surface) with a second resin composition containing a curable resin. Hereinafter, the curable resin contained in the second resin composition may be referred to as "(b) second curable resin". Step (IV) forms a second resin composition layer containing the second resin composition. Typically, this second resin composition layer contains only the second resin composition.

[0166] ((a) Explanation of the second inorganic filler) The second resin composition may or may not contain an inorganic filler. Hereinafter, the inorganic filler contained in the second resin composition may be referred to as "(a) second inorganic filler". If 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 granular form and may be contained in the second cured layer while maintaining that granular state.

[0167] When the second resin composition contains (a) a second inorganic filler, the range of the 99% particle size of (a) the second inorganic filler is usually 2 μm or less, preferably 1.5 μm or less, more preferably 1.0 μm or less, and even more preferably 0.5 μm or less. The lower limit may be, for example, 0.01 μm or more, 0.1 μm or more, etc. The 99% particle size of an inorganic filler such as (a) the second inorganic filler refers to the particle size at which the cumulative volume from the smallest 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) the second inorganic filler, or contains (a) the second inorganic filler having a 99% particle size within the above range, the formation of depressions on the polished surface of the cured layer (i.e., the polished surface of the second cured layer) can be suppressed.

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

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

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

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

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

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

[0174] (a) The second inorganic filler may be the same as the first inorganic filler (A), except that it has a particle size within the range described above. Therefore, the material for the second inorganic filler (a) may be the same as the material described for the first inorganic filler (A). In addition, the second inorganic filler (a) may be treated with a surface treatment agent, similar to the first inorganic filler (A). In this case, the type of surface treatment agent and the degree of surface treatment used to treat the second inorganic filler (a) may be the same as the type of surface treatment agent and the degree of surface treatment used to treat the first inorganic filler (A).

[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% by mass or more than 0% by mass relative to 100% by mass of the nonvolatile components in the second resin composition, for example, 30% by mass or more, 40% by mass or more, etc. The upper limit is preferably 90% by mass or less, more preferably 80% by mass or less, even more preferably 70% by mass or less, and particularly preferably 60% by mass or less. When the amount of (a) the second inorganic filler is within the above range, the formation of depressions on the polished surface of the cured layer can be effectively suppressed.

[0176] ((b) Explanation of the second curing resin) The (b) second curable resin, as component (b) in the second resin composition, is a curable resin and may be the same as the (B) first curable resin. Therefore, the (b) second curable resin may be a thermosetting resin, a photocurable resin, or a combination thereof. In particular, the (b) second curable resin preferably contains a thermosetting resin, and more preferably contains only a thermosetting resin.

[0177] (b) Examples of thermosetting resins that can be used as the second curing resin are the same as those that can be used as the first curing resin (B). In particular, the second curing resin (b) preferably contains an epoxy resin. Especially when both the first curing resin (B) and the second curing resin (b) contain an epoxy resin, the affinity between the first cured layer and the second cured layer can be improved, and the adhesion between the two layers can be enhanced, so that a cured layer with excellent mechanical strength can be obtained.

[0178] (b) The epoxy resin included in the second curing resin may be the same as the epoxy resin described in (B) the first curing resin. The range of the amount (mass%) of epoxy resin in the second resin composition may be the same as the range of the amount of epoxy resin in the first resin composition, but it is preferable to adjust the specific amount so that a second cured layer having the desired properties can be obtained.

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

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

[0181] The second resin composition preferably contains a curing agent in combination with the epoxy resin. (b) The curing agent included in the second curable resin may be the same as the curing agent included in the first curable resin described in (B). 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 curing agent in the first resin composition, but the specific amount is preferably adjusted so that a second cured layer with desired properties can be obtained.

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

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

[0184] When the second resin composition contains a combination of epoxy resin and a curing agent, the range of the number of active groups of the curing agent relative to the number of epoxy groups of the epoxy resin is preferably 0.1 or more, more preferably 0.3 or more, even more preferably 0.5 or more, 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 second resin composition refers to the sum of all values ​​obtained by dividing the mass of the nonvolatile components of the epoxy resin present in the second resin composition by the epoxy equivalent. The "number of active groups of the curing agent" in the second resin composition refers to the sum of all values ​​obtained by dividing the mass of the nonvolatile components of the curing agent present in the second resin composition by the active group equivalent.

[0185] The range of the amount (by 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 it is preferable to adjust the specific amount so that a second cured layer having the desired properties can be obtained.

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

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

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

[0189] ((c) Explanation of polymer resins) The second resin composition may contain (c) a polymer resin as an optional component. The (c) polymer resin is usually thermoplastic and is included in the second resin composition in a state of compatibility with resin components other than the (c) polymer resin. The (c) polymer resin as component (c) does not include those corresponding to components (a) to (b) described above. The (c) polymer resin included in the second resin composition may be the same as the (C) polymer resin that can be included in the first resin composition.

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

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

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

[0193] ((d) Explanation of curing accelerator) The second resin composition may contain (d) a curing accelerator as an optional component. The (d) curing accelerator can act as a catalyst in the reaction of (b) the second curable resin, thereby accelerating the curing of the second resin composition. The (d) curing accelerator as component (d) does not include those corresponding to components (a) to (c) described above. The (d) curing accelerator included in the second resin composition may be the same as the (D) curing accelerator that may be included in the first resin composition.

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

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

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

[0197] ((e) Explanation of adhesion aids) The second resin composition may contain (e) an adhesion promoter as an optional component. The adhesion promoter (e) can increase the adhesion strength between the cured layer and the layer in contact with the cured layer. The adhesion promoter (e) as component (e) does not include those corresponding to components (a) to (d) described above. The adhesion promoter (e) included in the second resin composition may be the same as the adhesion promoter (E) that may be included in the first resin composition.

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

[0199] ((f) Explanation of flame retardants) The second resin composition may contain (f) a flame retardant as an optional component. The flame retardant (f) can improve the flame retardancy of the cured layer. The flame retardant (f) as component (f) does not include components (a) to (e). The flame retardant (f) included in the second resin composition may be the same as the flame retardant (F) that may be included in the first resin composition.

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

[0201] (g) Description of any additives) The second resin composition may further contain (g) any additive as an optional component. The (g) optional additive as a component does not include any of the components (a) to (f) described above. The (g) optional additive included in the second resin composition may be the same as the (G) optional additive that may be included in the first resin composition.

[0202] ((h) Explanation of solvents) The second resin composition may contain, in combination with the non-volatile components such as components (a) to (g) described above, an optional volatile component, namely (h) solvent. The (h) solvent included in the second resin composition may be the same as the (H) solvent included in the first resin composition.

[0203] The amount of (h) solvent in the second resin composition forming the second resin composition layer is preferably small. The amount of (h) solvent in the second resin composition is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 4% by mass or less, even more preferably 3% by mass or less, and even 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 0.0001% by mass or more.

[0204] (Description of the properties of the second resin composition and its cured product) The second resin composition forms a cured product upon curing. Hereinafter, the cured product of the second resin composition may be referred to as the "second cured product." This second cured product forms the second cured layer. During curing, heat is usually applied to the second resin composition, so among the components contained in the second resin composition, (h) solvent, which is a volatile component, may volatilize due to the heat during curing. Therefore, the second cured product may contain non-volatile components of the second resin composition or their reaction products.

[0205] The second cured product typically 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 between the elastic modulus G1 of the first cured product and the elastic modulus G2 of the second cured product is preferably 1.1 or more, more preferably 1.3 or more, even more preferably 1.5 or more, preferably 10 or less, more preferably 6 or less, and even more preferably 4 or less. When the elastic modulus ratio G1 / G2 is within the above range, warping of the circuit board and intermediate products during its manufacturing can be effectively suppressed, and the manufacturing 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, and even 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 manufacturing can be effectively suppressed, and the manufacturing of the circuit board can be carried out smoothly. In addition, it is usually possible to suppress the formation of polishing marks on the second cured layer and suppress resin clogging of the polishing equipment, so that the 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. If the sample is the second resin composition before curing, the second resin composition may be cured at 180°C for 90 minutes to obtain the 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 (e.g., (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 the polymer resin).

[0209] The second cured product preferably has a small dielectric loss tangent. The dielectric loss tangent range of the second cured product is preferably 0.020 or less, more preferably 0.010 or less, and even more preferably 0.005 or less. There is no particular limit to the lower limit, and it may be, for example, 0.0001 or more. The dielectric loss tangent of the second cured product can be measured by the same method as the dielectric loss tangent of the first cured product. If the sample is a 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 dielectric loss tangent of the second cured product may be measured.

[0210] (Explanation of the manufacturing method for the second resin composition) The second resin composition can be manufactured by mixing components that may be included in the second resin composition, just like the first resin composition.

[0211] (Explanation 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. The method for forming the second resin composition layer may be the same as the method for forming the first resin composition layer.

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

[0213] Furthermore, the formation of the second resin composition layer in step (IV) may be carried out using, for example, a resin sheet comprising a support and a second resin composition layer formed on the support. When a resin sheet is used, 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 to form the second resin composition layer may be the same as the resin sheet used to form the first resin composition layer in step (I), except that it comprises a second resin composition layer instead of the first resin composition layer. Also, the resin sheet used to form the second resin composition layer can be manufactured in the same way 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 be the same as those used to form the first resin composition layer in step (I).

[0214] Similar to the method for forming the first resin composition layer, after lamination, the formed second resin composition layer may be smoothed by pressing a heat-pressure bonding member from the support side under normal pressure (atmospheric pressure). If 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 steps (IV) and (V), or after step (V).

[0215] Furthermore, the formation of the second resin composition layer in step (IV) may be carried out by, for example, a method including the application of the second resin composition. This method for forming the second resin composition layer, including the application, may be carried out in the same manner as the method for forming the first resin composition layer, including the application. In this case, 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, the die coating method is preferred.

[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 even more preferably 50 μm or more. Generally, polishing reduces the thickness of the second cured layer, but if the thickness of the second resin composition layer before polishing is equal to or greater than the lower limit, a second cured layer with 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 even more preferably 100 μm or less, from the viewpoint of suppressing warping of intermediate products during the manufacturing of circuit boards.

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

[0218] The curing of the second resin composition layer can be carried out by an appropriate method depending on the type of (b) second curable resin. For example, if (b) the second curable resin contains a thermosetting resin, the second resin composition layer may be cured by heating. Alternatively, for example, if (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) is to cure the second resin composition layer by heating. The range of curing conditions such as curing temperature and curing time for the second resin composition layer may be the same as the range of curing conditions for 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 conditions for preheating the second resin composition layer may be the same as the range of conditions for preheating the first resin composition layer.

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

[0221] Furthermore, the second cured layer typically has a dielectric loss tangent within the same range as the dielectric loss tangent of the second cured product described above. In addition, the second cured layer typically has the same thickness as the second resin composition layer before curing.

[0222] <Step (VI) of polishing the second hardened layer> A method for manufacturing a circuit board according to one embodiment of the present invention includes, after step (V), step (VI) of polishing the surface of the second hardened layer opposite to the first hardened layer. Polishing provides a smooth polished surface as the polished surface of the second hardened layer. The same method as the polishing method for the first hardened layer may be used for polishing the second hardened layer.

[0223] Polishing reduces the thickness of the second hardened layer. The amount of thickness reduction is equal to the thickness of the second hardened layer before polishing (T2). b And, the thickness T2 of the second hardened layer after polishing a Difference T2 b -T2 a This is represented by: The amount of reduction in the thickness of the second hardened layer due to polishing T2 b -T2 a The thickness is usually 10 μm or more, preferably 20 μm or more, and more preferably 30 μm or more. The upper limit is the thickness T2 of the second hardened layer before polishing. b This value is smaller and can be set so that a second hardened layer of the desired thickness is obtained after polishing.

[0224] Typically, the thickness of the second hardened layer after polishing is T2 a This is the thickness of the first hardened layer (thickness of the first hardened layer after polishing) T1 aSmaller. Generally, (A) the first hardened layer containing the first inorganic filler has excellent mechanical properties such as linear thermal expansion coefficient and mechanical strength, as well as excellent electrical properties such as dielectric loss tangent. Therefore, when the first hardened layer, which has such excellent properties, is thick and the second hardened layer is thin, the properties of the hardened layer formed by the combination of the first and second hardened layers can be made particularly good. Thickness T2 of the second hardened layer after polishing in step (VI) a and the thickness T1 of the first hardened layer a T2 a / T1 a The range is preferably 0.9 or less, more preferably 0.5 or less, and even more preferably 0.2 or less. The lower limit may 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 the value is within the aforementioned range, the warping of the circuit board can usually be effectively suppressed.

[0225] In terms of particularly effectively suppressing warping of the circuit board, the elastic modulus G1 of the first hardened layer and the thickness T1 of the first hardened layer after polishing are important. a The product of the two factors, the elastic modulus G2 of the second hardened layer, and the thickness T2 of the second hardened layer after polishing. a The ratio of the product of (G1 × T1 a ) / (G2×T2 a It is preferable that the ratio "(G1 × T1)" is within a specific range. a ) / (G2×T2 a The specific range of ) is preferably 5 or more, more preferably 8 or more, and even more preferably 10 or more. The upper limit is preferably 100 or less, but may be 80 or less or 50 or less.

[0226] From the viewpoint of smoothly polishing the second hardened layer, it is preferable to suppress not only the warping of the circuit board obtained after polishing the second hardened layer, but also the warping of the intermediate product obtained before polishing the second hardened layer. From the viewpoint of suppressing the warping of both the circuit board and its intermediate product, the ratio of the elastic modulus G1 of the first hardened layer and the elastic modulus G2 of the second hardened product, G1 / G2, and the thickness T2 of the second hardened layer after polishing are desirable. a and the thickness T2 of the second hardened layer before polishing b Ratio T2 a / T2b The parameter "(G1 / G2) × (T2)" is expressed as the product of the two. a / T2 b It is preferable that the parameter "(G1 / G2) × (T2)" is within a specific range. a / T2 b The specific range of ) is preferably 1.2 or less, more preferably 1.1 or less, even more preferably 1.0 or less, and particularly preferably 0.9 or less. The lower limit is preferably 0.1 or more, but may be 0.2 or more or 0.3 or more.

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

[0228] In the manufacturing method according to this embodiment, a hardened material layer can be formed by combining a first hardened layer and a second hardened layer after polishing. The outermost surface of this hardened material layer is formed by the surface of the second hardened layer opposite to the first hardened layer. Since the surface of the second hardened layer is polished in step (VI), this surface can form the polished surface of the hardened material layer. Furthermore, since the recesses that were present in the polished surface of the first hardened layer are filled by the second hardened layer, these recesses do not appear on the polished surface of the hardened material layer. Therefore, by the manufacturing method according to this embodiment, a circuit board with a hardened material layer having a smooth polished surface with suppressed recess formation can be obtained. In one example, the number of recesses with a diameter of 5 μm or more on the polished surface of the hardened material layer is reduced to 1 cm 2 The number of winning tickets can be preferably less than 30, and more preferably less than 10.

[0229] The polished surface of the hardened layer (i.e., the polished surface of the second hardened layer) usually has a low surface roughness. For example, the arithmetic mean roughness of the polished surface of the second hardened layer is preferably 500 nm or less, more preferably 300 nm or less, and particularly preferably 100 nm or less. There is no particular lower limit, and it may be, for example, 10 nm or more, 20 nm or more, 50 nm or more, etc.

[0230] The polished surface of the cured layer (i.e., the polished surface of the second cured layer) preferably has high hardness. For example, the Vickers hardness of the polished surface of the cured layer is preferably 10 HV or higher, more preferably 20 HV or higher, even more preferably 30 HV or higher, preferably 200 HV or lower, more preferably 150 HV or lower, and even more preferably 100 HV or lower. When the first cured product has such a high Vickers hardness, the polishing of the second cured layer in step (VI) can be carried out smoothly. For example, it is possible to suppress the formation of polishing marks on the second cured layer and to suppress resin clogging of the polishing equipment.

[0231] Vickers hardness can be measured using a Vickers hardness tester. A specific method for measuring Vickers hardness can be adopted from the method described in the examples (Vickers hardness measurement test) below. The Vickers hardness of the cured layer can be adjusted, for example, by the composition 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 of the photosensitive resin composition. The wettability of the polished surface of the cured layer can be expressed, 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, even more preferably 20° or more, preferably 90° or less, more preferably 80° or less, and even more preferably 70° or less. The polished surface of the cured layer may be coated with a photosensitive resin composition 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, it is possible to suppress the repulsion of the photosensitive resin composition and suppress the formation of depressions in the photosensitive resin composition layer. In conventional cured resin compositions, it was sometimes difficult to adopt a composition with excellent wettability of the photosensitive resin composition due to constraints on electrical and mechanical properties. In contrast, in this embodiment, a composition with excellent electrical and mechanical properties can be used for the first cured layer, while a composition with excellent wettability can be used for the second cured layer. Therefore, it is possible to achieve good electrical and mechanical properties for the entire cured layer while also achieving excellent wettability of the polished surface of the cured layer. The contact angle can be measured using the droplet method with the θ / 2 method. Specifically, a droplet of 1.0 μL of the photosensitive resin composition can be applied to the polished surface, and the contact angle can be measured 2000 ms after the droplet has adhered.

[0233] Typically, manufactured circuit boards can be made less warped. In one example, the amount of warping of the circuit board is preferably less than 4000 μm, more preferably less than 3000 μm, and even 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 example described later.

[0234] <Optional steps> The method for manufacturing a circuit board according to this embodiment may include any additional steps in combination with the steps (I) to (VI) described above.

[0235] The method for manufacturing a circuit board according to this embodiment may include, for example, a step (VII) after step (VI) for forming holes such as via holes and through holes in the cured layer. 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 to form the cured layer. For example, holes may be formed by processing methods such as drilling, laser processing, and plasma processing, with laser processing being preferred. 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 roughening the polished surface of the cured material layer. The roughening treatment can roughen the polished surface of the cured material layer. Furthermore, the roughening treatment can remove smear (resin residue) from the cured material layer. For this reason, this roughening treatment is sometimes called "desmear treatment". For example, if holes are formed in step (VII), smear may be formed inside those holes, so it is preferable to perform the roughening treatment in step (VIII) after step (VII) to remove the smear.

[0237] The procedure and conditions for the roughening treatment are not particularly limited. For example, the roughening treatment may be carried out by applying swelling treatment with a swelling solution, oxidation treatment with an oxidizing agent, and neutralization treatment with a neutralizing solution to the hardened layer in this order.

[0238] Examples of swelling solutions used for roughening treatment include alkaline solutions and surfactant solutions, with alkaline solutions being preferred. Sodium hydroxide solution and potassium hydroxide solution are more preferred as the alkaline solution. Examples of commercially available swelling solutions include "Swelling Dip Securing P" and "Swelling Dip Securing SBU" manufactured by Atotec Japan. Swelling treatment with a swelling solution can be carried out, for example, by immersing the cured material layer in a swelling solution at 30°C to 90°C for 1 to 20 minutes. From the viewpoint of suppressing the swelling of the resin in the cured material layer to an appropriate level, it is preferable to immerse the cured material layer in a swelling solution at 40°C to 80°C for 5 to 15 minutes.

[0239] Examples of oxidizing agents used in the roughening treatment include alkaline permanganate solutions obtained by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. The oxidation treatment with an oxidizing agent such as an alkaline permanganate solution is preferably carried out by immersing the hardened layer in an oxidizing agent solution heated to 60°C to 100°C for 10 to 30 minutes. Furthermore, the concentration of permanganate in the alkaline permanganate solution is preferably 5% to 10% by mass. Examples of commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact CP" and "Dosing Solution Securigans P" manufactured by Atotec Japan.

[0240] As the neutralizing solution used for roughening treatment, an acidic aqueous solution is preferred, and a commercially available example is "Reduction Solution Securigant P" manufactured by Attec Japan. Neutralization treatment with a neutralizing solution can be carried out by immersing the treated surface, which has been oxidized with an oxidizing agent, in a neutralizing solution at 30°C to 80°C for 5 to 30 minutes. From the viewpoint of workability, it is preferable to immerse the object that has been oxidized with an oxidizing agent in a neutralizing solution at 40°C to 70°C for 5 to 20 minutes.

[0241] The method for manufacturing a circuit board according to this example may include a step (IX) of forming a conductive layer on the polished surface of the cured material layer. If the method for manufacturing a circuit board includes step (VII) or (VIII), it is preferable that the step of forming the conductive layer (IX) is 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 alloy, copper-nickel alloy, and copper-titanium alloy). Among them, from the viewpoints of versatility, cost, and ease of patterning in 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 hardened material layer by electroless plating. Next, a mask pattern is formed on the formed electroless plating layer, exposing a portion of the electroless plating layer corresponding to the desired wiring pattern. After forming an electroplating layer on the exposed electroless plating layer by electroplating, the mask pattern is removed. Subsequently, the unnecessary electroless plating layer can be removed by etching to form a conductor layer having the desired wiring pattern.

[0247] Since the polished surface of the hardened layer is a smooth plane with suppressed recess formation, if 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" refers to the wiring width and "space" refers to the spacing 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, even more preferably 3 μm / 3 μm or less, preferably 0.1 μm / 0.1 μm or more, more preferably 0.5 μm / 0.5 μm or more, and even more preferably 1 μm / 1 μm or more. The wiring pitch of the conductor layer is preferably 20 μm or less, more preferably 10 μm or less, even more preferably 6 μm or less, preferably 0.2 μm or more, more preferably 1 μm or more, and even more preferably 2 μm or more. The line / space ratio and wiring pitch may be uniform or non-uniform throughout the entire conductor layer.

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

[0249] In the method for manufacturing a circuit board, each of the above-described steps may be performed only once or 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 comprising multiple cured material layers and conductive layers.

[0250] <Specific examples of circuit boards> Examples of circuit boards manufactured by the manufacturing method according to the above-described embodiment include printed circuit boards and semiconductor chip packages. Examples of semiconductor chip packages include fan-in type packages and fan-out type packages. Specifically, examples include 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. In these semiconductor chip packages, it is preferable to form a sealing layer or a redistribution layer with a cured material layer as a combination of the first cured layer and the second cured layer described above. However, the circuit board is not limited to those exemplified herein.

[0251] The following describes a method for manufacturing a semiconductor chip package as a first example of a circuit board. The semiconductor chip package described in this first example comprises an inner layer circuit substrate, a semiconductor chip mounted on the inner layer circuit substrate, and a sealing layer that seals at least a portion of the semiconductor chip. In this first example, the sealing layer is formed by a cured material layer.

[0252] The first example of a circuit board manufacturing method includes a step of bonding a semiconductor chip to an inner layer circuit substrate. The bonding conditions between the inner layer circuit substrate and the semiconductor chip can be any conditions that allow conductive connection between the terminal electrodes of the semiconductor chip and the circuit wiring of the inner layer circuit substrate. For example, conditions used in flip-chip mounting of semiconductor chips may be adopted.

[0253] One bonding method is to press the semiconductor chip onto the inner layer circuit substrate. The pressing conditions are typically a pressing temperature in the range of 120°C to 240°C (preferably 130°C to 200°C, more preferably 140°C to 180°C) and a pressing time in the range of 1 second to 60 seconds (preferably 5 seconds to 30 seconds). Another bonding method is to place the semiconductor chip on the inner layer circuit substrate and bond it by reflow. The reflow conditions may be in the range of 120°C to 300°C. Furthermore, the manufacturing method of the circuit board according to the first example may include filling the gap between the semiconductor chip and the inner layer circuit substrate with an underfill material after bonding the semiconductor chip to the inner layer circuit substrate.

[0254] The first example of a circuit board manufacturing method includes a step of forming a sealing layer as a cured material layer that seals at least a portion of the semiconductor chip after bonding the semiconductor chip to the inner layer circuit substrate. The sealing layer can be formed by a method including the steps (I) to (VI) described above. Since the formed sealing layer is a cured material layer formed by a method including steps (I) to (VI), it can have a polished surface in which the formation of recesses is suppressed. Therefore, layer formation on the polished surface can be carried out smoothly.

[0255] The following describes a method for manufacturing a semiconductor chip package as a second example of a circuit board. Figure 7 is a schematic cross-sectional view showing a semiconductor chip package as a circuit board according to the second example of the present invention. As shown in Figure 7, the semiconductor chip package 600 described in this second example comprises a semiconductor chip 610; a sealing layer 620 formed to cover the periphery of the semiconductor chip 610; a redistribution forming layer 630 as an insulating layer provided on the side 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 forming layer 630 may be formed by a cured material layer.

[0256] The semiconductor chip package described in this second example is: (1) A step of obtaining a temporary substrate by laminating a temporary fixing film onto the substrate, (2) A step of temporarily fixing the semiconductor chip onto a temporary fixing film of a temporary substrate, (3) A step of forming a sealing layer on a semiconductor chip, (4) Steps to peel the temporary substrate from the semiconductor chip, (5) A step of forming a redistribution layer on the surface from which the temporary substrate of the semiconductor chip has been peeled off, and (6) Step of forming a redistribution layer as a conductor layer on the redistribution formation layer. The product can be manufactured by a method that includes these steps in this order. In this manufacturing method, the formation of the sealing layer in step (3) or the formation of the rewiring layer in step (5) may be carried out by a method that includes the steps (I) to (VI) described above.

[0257] In step (1), a temporary fixing film is laminated onto the substrate to obtain a temporary substrate. For example, the substrate and temporary fixing film described above are used.

[0258] In step (2), the semiconductor chip is temporarily fixed onto a temporary fixing film on a temporary substrate. Typically, the semiconductor chip is temporarily fixed onto the temporary fixing film such that the electrode pad surface of the semiconductor chip is in contact with the temporary fixing film. Temporary fixing of the semiconductor chip can be performed using known equipment such as a flip-chip bonder or die bonder. The layout and number of semiconductor chips can be appropriately set according to the shape and size of the temporary fixing film and the target number of semiconductor chip packages to be produced. For example, the semiconductor chips may be temporarily fixed in a matrix arrangement of multiple rows and multiple columns.

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

[0260] In step (4), the temporary substrate is peeled off from the semiconductor chip. The method for peeling off the detachable substrate can be appropriately selected depending on the material of the temporary fixing film. For example, methods include peeling off the temporary fixing film by heating and foaming (or expanding) it, and peeling off the temporary fixing film by irradiating it with ultraviolet light through the substrate to reduce its adhesive strength. In the method of peeling off the temporary fixing film by heating and foaming (or expanding) it, the heating conditions are usually 100°C to 250°C for 1 second to 90 seconds or 5 minutes to 15 minutes. In the method of peeling off the temporary fixing film by irradiating it with ultraviolet light through the substrate to reduce its adhesive strength, the amount of ultraviolet light irradiated is usually 10 mJ / cm². 2 ~1000 mJ / cm 2 That is the case.

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

[0262] In step (6), a redistribution layer is formed on the redistribution-forming layer as a conductive layer. 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 hardened layer that forms the redistribution-forming layer. Since the formation of recesses 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 semiconductor chip package manufacturing method 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). Furthermore, the semiconductor chip package manufacturing method 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 a plurality of semiconductor chip packages into individual semiconductor chip packages to form individual pieces.

[0264] The above-described second example 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-1 (RDL-1 st ) method). The method for manufacturing a circuit board according to the above-described embodiment is applicable regardless of the difference between the Chip-1 st method and the RDL-1 st method.

[0265] <Semiconductor Device> The above-described circuit board can be used in the manufacture of a semiconductor device. A semiconductor device includes the above-described circuit board. Examples of the semiconductor device include various semiconductor devices used in electrical 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 aircraft, 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> In a reaction vessel, 69 g of bifunctional hydroxyl-terminated polybutadiene (G-3000, manufactured by Nippon Soda Co., Ltd., number average molecular weight = 3000, hydroxyl group equivalent = 1800 g / eq.), 40 g of Ipsol 150 (aromatic hydrocarbon mixed solvent, manufactured by Idemitsu Petrochemical Co., Ltd.), and 0.005 g of dibutyltin laurate were mixed and dissolved uniformly. Once homogeneous, the temperature was raised to 50°C, and while stirring, 8 g of isophorone diisocyanate (IPDI, manufactured by Evonik Degussa Japan, isocyanate group equivalent = 113 g / eq.) was added and the reaction was carried out for approximately 3 hours. Next, the reaction mixture was cooled to room temperature, and then 23 g of cresol novolac resin (DIC Corporation "KA-1160", hydroxyl group equivalent = 117 g / eq.) and 60 g of ethyl diglycol acetate (Daicel Corporation) were added. The mixture was heated to 80°C while stirring and the reaction was carried out for approximately 4 hours. FT-IR reading: 2250 cm⁻¹ -1 The disappearance of the NCO peak was confirmed. The disappearance of the NCO peak was considered the endpoint of the reaction, and the reactants were cooled to room temperature and filtered through a 100-mesh filter cloth to obtain polymer resin A (50% by mass of nonvolatile components).

[0268] <Combination example 1> 3 parts of bisphenol-type epoxy resin (ZX-1059, manufactured by Nippon Steel Chemical & Material Co., Ltd., a 1:1 mixture of bisphenol A and bisphenol F, epoxy equivalent 169 g / eq.), 4 parts of naphthalene-type epoxy resin (HP-4032D, manufactured by DIC Corporation, 1,6-bis(glycidyloxy)naphthalene, epoxy equivalent approximately 145 g / eq.), 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 m²). 2Resin composition 1 was prepared by uniformly dispersing 110 parts of (1 / g), 4 parts of a compound having a methacryloyl group and a polyethylene oxide structure (BPE-1300N, manufactured by Shin-Nakamura Chemical Industry Co., Ltd., methacryloyl group equivalent: 842 g / eq.), 10 parts of an acid anhydride curing agent (HNA-100, manufactured by Shin-Nippon Rika Co., Ltd., acid anhydride group equivalent: 179 g / eq.), 0.1 parts of a silane coupling agent (KBM403, manufactured by Shin-Etsu Chemical Co., Ltd. (3-glycidoxypropyltrimethoxysilane)), and 0.5 parts of a curing accelerator (2MA-OK-PW, an imidazole curing accelerator, manufactured by Shikoku Chemicals Co., Ltd.) using a mixer.

[0269] <Combination 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.)), use 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 m²). 2 Resin composition 2 was prepared using the same method as in formulation example 1, except that 90 parts ( / g) were used.

[0270] <Combination example 3> 3 parts liquid bisphenol A type epoxy resin (Mitsubishi Chemical Corporation "jER828EL", epoxy equivalent 180 g / eq.), 4 parts naphthylene ether type epoxy resin (DIC Corporation "HP6000L", epoxy equivalent 215 g / eq.), 3 parts bixylenol type epoxy resin (Mitsubishi Chemical Corporation "YX4000HK", epoxy equivalent approximately 185 g / eq.), 3 parts cresol novolac resin (DIC Corporation "KA-1160", hydroxyl group equivalent 117 g / eq.), carbodiimide resin (Nisshinbo Chemical Corporation "V-03", carbodiimide equivalent 216 g / eq., non-volatile component 50 2 parts of a toluene solution (by mass%), 16.9 parts of an active ester compound (DIC Corporation's "HPC-8000-65T", weight-average molecular weight approximately 2700, active group equivalent approximately 223 g / eq., toluene solution with 65% by mass of nonvolatile components), 10 parts of phenoxy resin (Mitsubishi Chemical Corporation's "YX7553BH30", a 1:1 solution of cyclohexanone:methyl ethyl ketone (MEK) with 30% by mass of solids), inorganic filler 3 (spherical silica surface-treated with an amine-based alkoxysilane compound (Shin-Etsu Chemical Co., Ltd.'s "KBM573", average particle size 0.1 μm, 99% particle size 0.4 μm, specific surface area 10.4 m²) 2 40 parts of (1 / g), 0.05 parts 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] <Combination example 4> Inorganic filler 3 (spherical silica surface-treated with an amine-based alkoxysilane compound (KBM573, manufactured by Shin-Etsu Chemical Co., Ltd.)) 40 parts were omitted. In addition, the amount of methyl ethyl ketone was changed to 4 parts. Furthermore, cyclohexane 5 parts were omitted. Except for the above, resin composition 4 was prepared by the same method as in formulation example 3.

[0272] <Combination 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 and bisphenol F, 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 parts of flame retardant (HCA-HQ, manufactured by Sanko Co., Ltd., 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide, average particle size 2 μm), cresol novolat 2 parts of resin (DIC Corporation "KA-1160", hydroxyl group equivalent = 117 g / eq.), 0.5 parts of benzoxazine compound (JFE Chemical Corporation "ODA-BOZ", benzoxazine ring equivalent 218 g / eq.), 4.6 parts of active ester compound (DIC Corporation "HPC-8000-65T", weight-average molecular weight approximately 2700, active group equivalent approximately 223 g / eq., toluene solution with 65% by mass of nonvolatile components), 4 parts of polymer resin A (50% by mass of nonvolatile components), inorganic filler 1 (spherical silica surface-treated with amine-based alkoxysilane compound (Shin-Etsu Chemical Co., Ltd. "KBM573"), average particle size 3.5 μm, 99% particle size 9.5 μm, specific surface area 4.5 m²) 2 90 parts of (1 / g), 0.05 parts 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] <Combination 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.)), use 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 m²) 2 70 parts ( / g) were used. In addition, the amount of methyl ethyl ketone was changed to 5 parts. Furthermore, the amount of cyclohexanone was changed to 5 parts. Except for the above, resin composition 6 was prepared by the same method as in formulation example 5.

[0274] <Combination example 7> Resin composition 7 was prepared in the same manner as in Example 1, except that the amount of 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] <Combination example 8> The amount of polymer resin A (50% by mass of non-volatile components) was changed to 20 parts. In addition, the amount of 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. Except for the above changes, resin composition 8 was prepared by the same method as in formulation example 5.

[0276] <Combination example 9> Instead of 40 parts of inorganic filler 3 (spherical silica surface-treated with an amine-based alkoxysilane compound ("KBM573" manufactured by Shin-Etsu Chemical Co., Ltd.)), use inorganic filler 4 (spherical silica surface-treated with an amine-based alkoxysilane compound ("KBM573" manufactured by Shin-Etsu Chemical Co., Ltd.), average particle size 0.3 μm, 99% particle size 1.0 μm, specific surface area 10.3 m²). 2 Resin composition 9 was prepared in the same manner as in formulation example 3, except that 40 parts ( / g) were used.

[0277] <Measurement test of elastic modulus> Cured samples were prepared using resin compositions 1, 2, and 7 from formulation examples 1, 2, and 7, respectively, by the following method. Specifically, a 300 μm thick layer of the resin composition was formed on a demolded 12-inch silicon wafer by compression molding using a compression molding apparatus (mold temperature: 130°C, pressure: 6 MPa, curing time: 10 minutes). The resin composition was then peeled off the silicon wafer and heated at 180°C for 90 minutes to thermally cure it and obtain a cured sample.

[0278] Cured samples were prepared using resin compositions 3-6, 8, and 9 of other formulation examples by the following method. Specifically, the resin composition was uniformly applied to a release-treated PET film (Lintec Corporation, "PET501010") using a die coater so that the thickness of the dried resin composition layer was 100 μm, and dried at 80°C to 110°C (average 95°C) for 6 minutes. After that, the resin composition layer was cured by heat treatment at 180°C for 90 minutes, and the support was peeled off to obtain a cured sample.

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

[0280] <Measurement test of dielectric loss tangent> The dielectric loss tangent of hardened samples prepared using the same method as described above for the <measurement test of elastic modulus> was measured using a measuring device (Agilent Technologies "HP8362B") by the cavity resonance perturbation method, under measurement conditions of a measurement temperature of 23°C and a measurement frequency of 5.8 GHz. Measurements were performed on two test pieces, and the average value was calculated.

[0281] <Manufacturing of resin sheets> Using the resin compositions 3, 4, 5, 6, 8, and 9 prepared in formulation examples 3, 4, 5, 6, 8, and 9, resin sheets having a resin composition layer with a dry thickness of 80 μm and resin sheets 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, Ltd., "Lumirror R80", 38 μm thick, softening point 130°C; hereinafter sometimes referred to as "release PET") treated with an alkyd resin-based release agent (Lintec Corporation, "AL-5") was prepared. The resin composition was uniformly applied to 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, a rough surface of a polypropylene film (Oji F-Tex Corporation, "Alfan MA-411", 15 μm thick) was laminated to the side of the resin sheet not bonded to the support, so as to bond with the resin composition layer. This resulted in a resin sheet having the support, resin composition layer, and protective film in this order.

[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. Subsequently, the first resin composition layer was heat-cured by heating at 180°C for 90 minutes to obtain a first cured layer with a thickness of 200 μm. Subsequently, the first hardened layer was polished using a grinder to reduce its thickness to 150 μm.

[0284] A protective film was peeled off a resin sheet (resin composition layer thickness 80 μm) manufactured using 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 bonded together to form a second resin composition layer. Lamination was performed by reducing the pressure to 13 hPa or less for 30 seconds, and then pressing at 100°C and a pressure of 0.74 MPa for 30 seconds. Unless otherwise specified, all laminations described below were performed under the same conditions. After peeling off the support, the second resin composition was heat-cured by heating at 180°C for 90 minutes to obtain the second cured layer. Subsequently, the second hardened layer was polished using a grinder to a thickness of 20 μm. Thus, a hardened layer (thickness 170 μm) was obtained containing the first hardened layer (thickness 150 μm) and the second hardened layer (thickness 20 μm) in that order from the silicon wafer side. Hereinafter, the component having the layer configuration of silicon wafer / first hardened layer / second hardened layer obtained by the above method may be referred to as "evaluation substrate A". Evaluation substrate A was evaluated by the following Vickers hardness test, dent evaluation test, warpage evaluation test, and wettability evaluation test.

[0285] (Vickers hardness test) Evaluation substrate A was cut into a rectangle measuring 3 cm x 4 cm. The Vickers hardness (HV) of the surface of the cured material layer was measured using a Vickers hardness tester (Mitutoyo Corporation).

[0286] (Indentation evaluation test) Evaluation substrate A was cut into 1cm x 1cm squares. The entire surface of the cured layer was observed with a scanning electron microscope (SEM), and the number of depressions originating from the inorganic filler was counted. Substrates with 30 or more depressions with a diameter of 5μm or larger were classified as "poor," those with 10 to less than 30 depressions were classified as "acceptable," and those with fewer than 10 depressions were classified as "good."

[0287] (Warping evaluation test) The amount of warpage of evaluation substrate A was measured in a room at 25°C using a shadow moiré measurement device (Akorometrix "ThermoireAXP"). The measurement was performed in accordance with the Japan Electronics and Information Technology Industries Association (JEITA) standard JEITA EDX-7311-24. Specifically, a virtual plane was calculated from all data of the substrate surface (surface of the cured material layer) in the measurement area using the least squares method. Using this virtual plane as the reference plane, the amount of warpage was determined by the difference between the minimum and maximum values ​​of the vertical distance (perpendicular to the reference plane) from the reference plane to the substrate surface.

[0288] The calculated amount of warping was evaluated according to the following criteria. "Excellent": The amount of warping was less than 2500 μm, and the amount of warping was evaluated as particularly small. "Good": The amount of warping was between 2500 μm and 3000 μm, and was evaluated as having sufficiently small warping. "Acceptable": The amount of warping was between 3000 μm and 4000 μm, and was evaluated as having a small amount of warping. "Defective": The warp amount was 4000 μm or more, and was evaluated as having a large amount of warp.

[0289] (Wettability evaluation test) A photosensitive polyimide resin (viscosity 6 Pa·s) was spin-coated onto the surface of the cured layer of evaluation substrate A using a spin coater (Mikasa "MS-A150") at a rotation speed of 2000 rpm. The coated photosensitive polyimide resin was pre-baked on a hot plate at 120°C for 4 minutes. This resulted in a thin film layer with a thickness of 5 μm on the cured layer. The wettability of the surface of the cured layer was evaluated by observing the thin film layer according to the following criteria. "Good": No repulsion or indentation of the photosensitive polyimide resin occurred on the surface of the cured layer. "Defective": The surface of the cured layer shows signs of photosensitive polyimide resin repulsion or indentation.

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

[0291] <Example 3> The evaluation substrate A was manufactured and evaluated using the same method as in Example 1, except that resin composition 2 manufactured in Formula 2 was used instead of resin composition 1 manufactured in Formula 1.

[0292] <Example 4> The evaluation substrate A was manufactured and evaluated using the same method as in Example 1, except that resin composition 2 manufactured in Formulating Example 2 was used instead of resin composition 1 manufactured in Formulating Example 1, and a resin sheet manufactured using resin composition 3 of Formulating Example 3 (resin composition layer thickness 80 μm) was used instead of a resin sheet manufactured using resin composition 4 of Formulating Example 4 (resin composition layer thickness 80 μm).

[0293] <Example 5> A protective film was peeled off a resin sheet (resin composition layer thickness 100 μm) manufactured using 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 (Nikko Materials' 2-stage build-up laminator "CVP700") so that the resin composition layer was bonded to the silicon wafer, and the support was peeled off. The aforementioned resin sheet (a resin sheet with a 100 μm thick resin composition layer manufactured using resin composition 5 of formulation example 5, with the protective film peeled off) was laminated again onto this resin composition layer to form a first resin composition layer with a thickness of 200 μm. After that, the support was peeled off.

[0294] Subsequently, the first resin composition layer was heat-cured by heating at 100°C for 30 minutes, and then at 180°C for 90 minutes, to obtain a first cured layer with a thickness of 200 μm. Subsequently, the first hardened layer was polished using a grinder to reduce its thickness to 150 μm.

[0295] A protective film was peeled off a resin sheet (resin composition layer thickness 80 μm) manufactured using 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 bonded together to form a second resin composition layer. After peeling off the support, the second resin composition layer was cured by heating at 180°C for 90 minutes to obtain the second cured layer.

[0296] Subsequently, the second hardened layer was polished using a grinder to a thickness of 20 μm. Thus, a hardened layer (thickness 170 μm) was obtained containing the first hardened layer (thickness 150 μm) and the second hardened layer (thickness 20 μm) in that order from the silicon wafer side. Hereinafter, the component having the silicon wafer / first hardened layer / second hardened layer structure obtained by the above method may be referred to as "evaluation substrate B". Evaluation substrate B was evaluated using the Vickers hardness test, dent evaluation test, warpage 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 manufactured using resin composition 3 of formulation example 3 (resin composition layer thickness 80 μm) was used instead of a resin sheet manufactured using resin composition 4 of formulation example 4 (resin composition layer thickness 80 μm).

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

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

[0300] <Example 9> The evaluation substrate A was manufactured and evaluated using the same method as in Example 1, except that resin composition 7 manufactured in Formula Example 7 was used instead of resin composition 1 manufactured in Formula Example 1.

[0301] <Example 10> Using the same method as in Example 1, a first resin composition layer was formed on a silicon wafer (thickness 775 μm), a first cured layer was formed by thermal curing, and the first cured layer was polished.

[0302] A protective film was peeled off a resin sheet (with a resin composition layer thickness of 80 μm) manufactured using resin composition 3 of formulation example 3. This resin sheet was laminated onto a first cured layer so that the resin composition layer was bonded to the first cured layer, and the support was peeled off. On this resin composition layer, the aforementioned resin sheet (a resin sheet with a resin composition layer of 80 μm thickness manufactured using resin composition 3 of formulation example 3, with the protective film peeled off) was further laminated to form a second resin composition layer with a thickness of 160 μm. The support was then peeled off. Subsequently, the second resin composition was heat-cured by heating at 180°C for 90 minutes to obtain the second cured layer. Subsequently, the second hardened layer was polished using a grinder to a thickness of 100 μm. Thus, a hardened layer (thickness 250 μm) was obtained containing the first hardened layer (thickness 150 μm) and the second hardened layer (thickness 100 μm) in that order from the silicon wafer side. Hereinafter, the component having the layer configuration of silicon wafer / first hardened layer / second hardened layer obtained by the above method may be referred to as "evaluation substrate C". This evaluation substrate C was evaluated by the Vickers hardness test, dent evaluation test, warpage evaluation test, and wettability evaluation test described in Example 1.

[0303] <Example 11> The evaluation substrate A was manufactured and evaluated in the same manner as in Example 1, except that a resin sheet manufactured using resin composition 9 of formulation example 9 (resin composition layer thickness 80 μm) was used instead of a resin sheet manufactured using resin composition 4 of formulation example 4 (resin composition layer thickness 80 μm).

[0304] <Comparative Example 1> A component having a silicon wafer / first cured layer (thickness 150 μm) layer structure (hereinafter sometimes referred to as "evaluation substrate D") was manufactured 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 manufactured using resin composition 4 of formulation example 4) was not performed. This evaluation substrate D was evaluated using the dent evaluation test, warpage evaluation test, and wettability evaluation test described in Example 1. In this Comparative Example 1, since the second cured layer was not formed, the surface of the first cured layer was evaluated in the dent evaluation test and wettability evaluation test. In the warpage evaluation test, the surface of the first cured layer was used as the substrate surface to determine the amount of warpage.

[0305] <Result> The composition of the resin compositions prepared using the above-described formulation examples is shown in Table 1 below. In Table 1, the amount of each component represents the amount of non-volatile components (parts by mass).

[0306] Furthermore, the results of the above-mentioned 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 first inorganic filler (A) contained in the first resin composition to the average particle size D2 of the second inorganic filler (a) contained in the second resin composition. "Thickness" column, "First Hardened Layer (Before Polishing)": The thickness of the first hardened layer before polishing. "Thickness" column, "First Hardened Layer (After Polishing)": The thickness of the first hardened layer after polishing. "Thickness" column, "First hardened layer + Second hardened layer (before polishing)": The thickness of the hardened material layer consisting of the first hardened layer and the second hardened layer before polishing the second hardened layer. "Thickness" column, "First hardened layer + Second hardened layer (after polishing)": The thickness of the hardened material layer consisting of the first hardened layer and the second hardened layer after polishing the second hardened layer. "Warpage": Results of warpage evaluation tests for evaluation boards A to D. "Indented areas": Results of the indentation evaluation test on the polished surface of the hardened material layer of evaluation substrates A to D. "Vickers hardness (HV)": Vickers hardness of the polished surface of the hardened material layer of evaluation substrates A to D. "Equivalent Modulus Ratio (G1 / G2)": The ratio of the elastic modulus G1 of the first hardened layer to the elastic modulus G2 of the second hardened layer. "Elastic modulus G1 (GPa)": Elastic modulus of the first hardened layer. "Elastic modulus G2 (GPa)": Elastic modulus of the second hardened layer. "Df": Dielectric loss tangent of the first hardened layer. "Wettability": The wettability of the polished surface of the hardened material layer.

[0307] [Table 1]

[0308] [Table 2]

[0309] [Table 3] [Explanation of Symbols]

[0310] 10 Inorganic filler 11. Particles of inorganic fillers 12. Particles of inorganic fillers 13 Holes 20 Curing resin 30 First resin composition 40 Curing resin 50 Second resin composition 100 Base material 100U Substrate surface 200 First hardened layer 200U First hardened layer surface 210 First resin composition layer 220 Recessed area 230 Recessed area 300 Second hardened layer 300U Second hardened layer surface 310 Second resin composition layer 400 Cured material layer 500 circuit boards 600 semiconductor chip packages 610 semiconductor chips 620 Sealing layer 630 Rewiring formation layer 640 Redistribution layer 650 solder resist layers 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 the first cured layer, The process of polishing the surface of the first hardened layer, A step of forming a second resin composition layer on the polished surface of the first cured layer using a second resin composition containing a curable resin. A step of curing the second resin composition layer to form a second cured layer, and This process includes, in this order, polishing the side of the second hardened layer opposite to the first hardened layer; The 99% particle size of the inorganic filler contained in the first resin composition is larger than 2 μm. A method for manufacturing a circuit board, wherein the second resin composition contains an inorganic filler, and 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 Vickers hardness of the polished second hardened layer surface is 10 HV or more.

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

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

5. A method for manufacturing a circuit board according to claim 1, comprising the step of forming a conductive layer on the surface of a polished second hardened layer.

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

7. A method for manufacturing a circuit board according to claim 1, wherein a sealing layer or a rewiring layer is formed by a first cured layer and a second cured layer.

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