Manufacturing method for package substrates

Abstract

To provide a method for manufacturing a package substrate that offers excellent embedding properties and can suppress dragging. [Solution] A method for manufacturing a package substrate, comprising the steps of (A) preparing a resin sheet comprising a support and a resin composition layer comprising a resin composition provided on the support; (B) laminating the resin composition layer of the resin sheet onto a substrate having conductive pillars on its surface so as to embed the conductive pillars; (C) curing the resin composition layer to form an insulating layer; and (D) polishing the surface of the insulating layer to expose the conductive pillars, wherein when the elongation rate of the support at 115°C in the TD direction or MD direction is A, and the elongation rate of the support at 23°C in the same direction as the elongation rate at 115°C is B, A / B is less than 1.30.

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing a package substrate. [Background technology]

[0002] A known method for packaging substrates such as semiconductor packages involves forming conductive pillars on a substrate, embedding these conductive pillars in a resin composition and curing it, and then polishing the insulating layer, which is the cured resin composition, to expose the upper surface of the conductive pillars (for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-125475 [Overview of the project] [Problems that the invention aims to solve]

[0004] Furthermore, in recent years, with the aim of further improving CPU performance, package substrates are required to have designs such as 2xD packages and component-embedded substrates, and among these, the technology of increasing the height of conductor pillars to connect with the upper and lower layers is attracting attention. In this case, tall conductor pillars are embedded together with Si chips and components in a resin composition and hardened, an insulating layer is formed on the conductor pillars, and then conductivity is achieved by polishing.

[0005] As a method for forming an insulating layer, from the viewpoint of improving the cycle time, the insulating layer is formed using a resin sheet comprising a support and a resin composition layer containing a resin composition provided on the support. When the height of the conductor pillar is high, it is necessary to increase the thickness of the resin composition layer in the resin sheet.

[0006] However, the inventors have found that if there is variation in the thickness of the resin composition layer of the resin sheet, the thinner parts of the resin composition layer cannot completely embed the conductor pillars, and voids may occur between the conductor pillars and the insulating layer. Furthermore, if there is variation in the thickness of the resin composition layer of the resin sheet, when the insulating layer is polished, some areas of the conductor pillars will be exposed while others will not. The inventors have also found that if polishing is continued to expose all the conductor pillars, the already exposed conductor pillars may be polished along with the insulating layer, resulting in the generation of conductor pillar shavings. In particular, when using a thick resin composition layer to embed tall conductor pillars, the generation of voids becomes more pronounced, and because a thick resin composition layer is used, the amount of polishing is also increased, further polishing of the already exposed conductor pillars. The generation of voids and shavings can cause short circuits. Hereinafter, embedding the resin composition layer completely around the conductor pillars will be referred to as "embedding," and polishing of already exposed conductor pillars will be referred to as "dragging."

[0007] This invention was conceived in view of the above-mentioned problems, and aims to provide a method for manufacturing a package substrate that has excellent embedding properties and can suppress drag. [Means for solving the problem]

[0008] The inventors of the present invention have diligently studied to solve the above problems and have found that the above problems can be solved by manufacturing a package substrate using a resin sheet equipped with a support whose elongation ratio (elongation at the breaking point) measured at a specific temperature has been adjusted, thereby completing the present invention.

[0009] In other words, the present invention includes the following: [1] (A) A step of preparing a resin sheet comprising a support and a resin composition layer provided on the support containing a resin composition, (B) A step of laminating a resin composition layer of a resin sheet onto a substrate on which conductive pillars are provided on the surface, so as to embed the conductive pillars. (C) A step of curing the resin composition layer to form an insulating layer, and (D) A method for manufacturing a package substrate, comprising the step of polishing the surface of the insulating layer to expose the conductor pillars, A method for manufacturing a package substrate, wherein when A is the elongation rate of the support in the TD direction or MD direction at 115°C, and B is the elongation rate of the support in the same direction as the elongation rate at 115°C at 23°C, A / B is less than 1.30. [2] The method for manufacturing a package substrate according to [1], wherein the thickness of the resin composition layer exceeds 100 μm. [3] A method for manufacturing a package substrate according to [1] or [2], wherein step (B) is performed by a vacuum lamination method. [4] A method for manufacturing a package substrate according to any one of [1] to [3], wherein the height of the conductor pillar is 70 μm or more. [5] A method for manufacturing a package substrate according to any one of [1] to [4], wherein the resin composition layer includes an inorganic filler. [6] The method for manufacturing a package substrate according to [5], wherein the inorganic filler content is 70% by mass or more when the nonvolatile components in the resin composition are taken as 100% by mass. [7] A method for manufacturing a package substrate according to any one of [1] to [6], wherein the curing shrinkage rate of the cured product obtained by heat-curing the resin composition layer at 200°C for 90 minutes is 0.20% or less. [8] A method for manufacturing a package substrate according to any one of [1] to [7], wherein C is the elongation rate of the support in the TD direction or MD direction at 140°C, and B is the elongation rate of the support in the same direction as the elongation rate at 140°C at 23°C, and C / B is 1.55 or less. [9] A method for manufacturing a package substrate according to any one of [1] to [8], wherein the value obtained by dividing the thickness tolerance of the resin composition layer by the thickness of the resin composition layer is 0.18 or less. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a method for manufacturing a package substrate that has excellent embedding properties and can suppress dragging. [Modes for carrying out the invention]

[0011] Hereinafter, the present invention will be described in detail according to its preferred embodiments. The present invention is not limited by the following description, and each component can be appropriately changed without departing from the gist of the present invention.

[0012] Before describing the manufacturing method of the package substrate of the present invention in detail, the resin sheet used in the manufacturing method of the present invention will be described.

[0013] In the present invention, the "MD direction (Machine Direction)" of the support means the longitudinal direction of the support when manufacturing the support, that is, the conveyance direction of the long support during manufacturing. Also, the "TD direction (Transverse Direction)" of the support means the width direction of the support when manufacturing the support, and is a direction orthogonal to the MD direction. Note that both the MD direction and the TD direction are directions orthogonal to the thickness direction of the support.

[0014] [Resin Sheet] The resin sheet includes a support and a resin composition layer including a resin composition provided on the support. When the elongation rate of the support at 115°C in the TD direction or MD direction is A, and the elongation rate of the support at 23°C in the same direction as the elongation rate at 115°C is B, A / B is less than 1.30.

[0015] Although the details of the resin sheet manufacturing method will be described later, the resin sheet can be manufactured by applying a resin varnish containing a resin composition onto a support and heating and drying it at around 115°C. Generally, the support used for the resin sheet expands when heated and contracts when the temperature returns to room temperature (around 23°C) after heating is complete. Therefore, after applying the resin varnish onto the support, the support expands when heated and dried, and contracts when the heating and drying is complete. At this time, variations in the thickness of the resin composition layer may occur due to the expansion and contraction of the support. In the present invention, the ratio (A / B) of the expansion rate A at 115°C, a temperature near the heating and drying temperature, to the expansion rate B at 23°C, a temperature near room temperature after heating and drying is complete, is adjusted to be less than 1.30. As a result, the support does not expand easily when heated and does not contract easily. This suppresses variations in the thickness of the resin composition layer of the resin sheet in the present invention, and even when the resin composition layer is laminated on a substrate with irregularities, such as a conductive pillar, it has excellent embedding properties and prevents dragging.

[0016] The following describes each layer of the resin sheet.

[0017] <Support> The support has an elongation ratio (A / B) of less than 1.30, where A is the elongation of the support in the TD or MD direction at 115°C, and B is the elongation of the support in the same direction at 23°C. By using such a support, even when a resin composition layer is laminated on a substrate with irregularities, such as a conductive pillar, excellent embedding properties are achieved and drag is suppressed. Here, the elongation of the support at each temperature refers to the average value of the top three results obtained by performing five measurements in accordance with JIS K7127:1999. The elongation of the support at each temperature can be measured by the method described in the examples below.

[0018] The ratio of elongation (A / B) is less than 1.30, preferably 1.29 or less, more preferably 1.28 or less, 1.27 or less, or 1.26 or less. From the viewpoint of improving processability when laminating the resin composition layer onto the conductive pillar, it is preferably 1.00 or more, more preferably 1.03 or more, even more preferably 1.05 or more, 1.07 or more, 1.08 or more, 1.09 or more, 1.10 or more, 1.11 or more, 1.12 or more, or 1.13 or more.

[0019] The elongation rate of the support at each temperature may be either the elongation rate in the TD direction or the elongation rate in the MD direction. However, for the elongation rates at 115°C and 23°C, the elongation rate in the same direction is measured and the ratio of the elongation rates (A / B) is determined. Similarly, for the elongation rates at 140°C and 23°C, the elongation rate in the same direction is measured and the ratio of the elongation rates (C / B) is determined (details will be described later). Generally, the elongation rate of the support in the MD direction and the elongation rate in the TD direction are approximately the same. Therefore, unless otherwise specified, the elongation rate of the support at each temperature is measured as representative of the elongation rate in the TD direction.

[0020] The elongation rate of the support changes depending on the manufacturing process of the resin sheet, such as the selection of the constituent materials of the support, the presence or absence of tension (stretching) applied during manufacturing, the axial direction of stretching, the degree of stretching, the heat treatment conditions after stretching, and the tension applied when the support is wound up (during transport). Therefore, in a preferred embodiment of the present invention, the support used in the present invention is one in which the conditions in the above-mentioned resin sheet manufacturing process have been adjusted so that the elongation rate ratio (A / B) is less than 1.30.

[0021] The elongation of the support at 115°C is preferably 120% or less, more preferably 110% or less, and even more preferably 100% or less. There is no particular lower limit, but it is preferably 30% or more, more preferably 35% or more, even more preferably 40% or more, 45% or more, 40% or more, 45% or more, 50% or more, 55% or more, 60% or more, or 60% or more.

[0022] The elongation of the support at 23°C is preferably 110% or less, more preferably 105% or less, even more preferably 100% or less, 95% or less, 90% or less, 85% or less, or 80% or less. There is no particular lower limit, but it is preferably 20% or more, more preferably 25% or more, even more preferably 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 55% or more, or 60% or more.

[0023] The elongation of the support at 140°C is preferably 130% or less, more preferably 125% or less, even more preferably 120% or less, 115% or less, 110% or less, or 105% or less. There is no particular lower limit, but it is preferably 40% or more, more preferably 45% or more, even more preferably 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, 80% or more, or 85% or more.

[0024] When C is the elongation of the support in the TD direction at 140°C, the ratio (C / B) of the elongation at 140°C to the elongation of the support in the same direction at 23°C B is preferably 1.55 or less, more preferably 1.53 or less, even more preferably 1.50 or less, or less than 1.50, from the viewpoint of significantly obtaining the effects of the present invention. From the viewpoint of improving processability when laminating the resin composition layer onto the conductive pillar, it is preferably 1.00 or more, more preferably 1.05 or more, even more preferably 1.10 or more, 1.15 or more, 1.20 or more, 1.25 or more, or 1.28 or more. The elongation of the support at each temperature can be measured by the method described in the examples below.

[0025] As a support, a film made of a plastic material (hereinafter also simply referred to as "plastic film") is preferably used from the viewpoint of being able to adjust the elongation rate. Examples of plastic materials include polyethylene terephthalate ("PET"), polyethylene naphthalate ("PEN"), polycarbonate ("PC"), polymethyl methacrylate (PMMA), cyclic polyolefin, triacetylcellulose (TAC), polyether sulfide (PES), polyether ketone, and polyimide. As the plastic film, either polyethylene terephthalate or polyethylene naphthalate is preferred, with polyethylene terephthalate being more preferred.

[0026] Conventional plastic films often have an elongation ratio (A / B) of less than 1.30. When a resin composition layer is laminated onto a substrate with irregularities, such as a conductive pillar, the embedding ability is poor, and dragging may occur. Therefore, in a preferred embodiment of the present invention, the plastic film is subjected to a preheat treatment to prepare a support that satisfies the elongation ratio (A / B). In addition to the preheat treatment, the conditions can be adjusted according to the type of plastic material, the presence or absence of tension (stretching) applied during manufacturing, the axial direction of stretching, the degree of stretching, and the heat treatment conditions after stretching, so that the elongation ratio (A / B) is less than 1.30.

[0027] When using a long plastic film, a preheating treatment to ensure that the elongation ratio (A / B) is less than 1.30 can be performed, for example, by heating the plastic film while applying tension in one or both of the MD and TD directions.

[0028] When using long plastic films, a predetermined tension is usually applied in the MD direction by conveying them using rolls such as transport rolls during manufacturing. Therefore, by heating while applying tension only in the TD direction, it is sometimes possible to obtain a support that satisfies a ratio of elongation in the TD direction (A / B) of less than 1.30.

[0029] In the MD direction, a predetermined tension can be applied by adjusting the tension on the plastic film stretched between multiple rolls. Furthermore, tension in the TD direction can be applied by any conventionally known and suitable means. In the TD direction, a predetermined tension can be applied using a tenter or the like with a conventionally known configuration.

[0030] Furthermore, for example, a predetermined tension can be applied to the plastic film in the MD direction or TD direction by utilizing the weight of a weight and gravity. Specifically, one edge of the plastic film in the direction to be adjusted is fixed to a support rod or the like using an arbitrarily suitable adhesive (e.g., Kapton adhesive tape, PTFE adhesive tape, glass cloth adhesive tape) so that the direction to be adjusted among the TD and MD directions coincides with the vertical direction, and the plastic film is suspended so that tension is applied uniformly to the entire film. After that, a weight such as a metal plate is attached to the other edge of the opposite direction to be adjusted using an arbitrarily suitable adhesive so that tension is applied uniformly to the entire plastic film, and preheating can be performed by heating while tension is applied by the weight of the weight.

[0031] The amount of tension applied to the plastic film can be set to any suitable tension, taking into consideration the material of the plastic film, the composition of the resin composition, etc. In one embodiment, the tension is preferably 1 gf / cm². 2 More than 5 gf / cm² 2 More preferably 10 gf / cm² 2 The above is preferable, with a concentration of 50 gf / cm³. 2 More preferably 45 gf / cm³ 2 More preferably 40 gf / cm³ 2 The following applies:

[0032] In one embodiment, the heating temperature for the preheating treatment is preferably (Tg+50)°C or higher, more preferably (Tg+60)°C or higher, even more preferably (Tg+70)°C or higher, and even more preferably (Tg+80)°C or higher or (Tg+90)°C or higher, where Tg (°C) is the glass transition temperature of the plastic film. The upper limit of the heating temperature is preferably (Tg+115)°C or lower, more preferably (Tg+110)°C or lower, and even more preferably (Tg+105)°C or lower, as long as it is below the melting point of the plastic film.

[0033] If the support is, for example, a PET film, the heating temperature for the preheating treatment is preferably 100°C or higher, more preferably 105°C or higher, even more preferably 110°C or higher, even more preferably 115°C or higher, 120°C or higher, 125°C or higher, or 130°C or higher. The upper limit of the heating temperature is preferably 190°C or lower, more preferably 185°C or lower, even more preferably 180°C or lower, 175°C or lower, 170°C or lower, 165°C or lower, 160°C or lower, 155°C or lower, or 150°C or lower.

[0034] The heating time can be appropriately determined according to the heating temperature so that the ratio of the elongation rate (A / B) is less than 1.30. In one embodiment, the heating time is preferably 1 minute or more, more preferably 5 minutes or more, even more preferably 10 minutes or more, 15 minutes or more, or 20 minutes or more. The upper limit of the heating time depends on the heating temperature, but is preferably 120 minutes or less, more preferably 90 minutes or less, even more preferably 60 minutes or less, 55 minutes or less, 50 minutes or less, or 45 minutes or less.

[0035] The atmosphere used when performing the preheating treatment is not particularly limited and can include, for example, an air atmosphere or an inert gas atmosphere (nitrogen gas atmosphere, helium gas atmosphere, argon gas atmosphere, etc.). An air atmosphere is preferred from the viewpoint of being able to easily prepare the support.

[0036] The preheating treatment may be carried out under reduced pressure, atmospheric pressure, or pressurized pressure, but it is preferable to carry it out under atmospheric pressure from the viewpoint of easily preparing the support.

[0037] The support may have a matte finish or corona treatment applied to the surface that joins with the resin composition layer, as described later. Alternatively, a support with a release layer may be used, which has a release layer on the surface that joins with the 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 resins, polyolefin resins, urethane resins, and silicone resins.

[0038] The thickness of the support is not particularly limited, but is preferably 5 μm or more, more preferably 10 μm or more, even more preferably 15 μm or more, 20 μm or more, 25 μm or more, or 30 μm or more, and preferably 75 μm or less, more preferably 60 μm or less, even more preferably 55 μm or less, 50 μm or less, or 45 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.

[0039] <Resin composition layer> The resin sheet has a resin composition layer. The resin composition layer is a layer containing the resin composition, and usually contains only the resin composition. The resin composition layer can form an insulating layer by thermal curing. The insulating layer usually contains a cured product of the resin composition layer, and preferably contains only the cured product of the resin composition layer.

[0040] The resin composition is acceptable as long as its cured product has sufficient hardness and insulating properties. The resin composition contains (a) an inorganic filler from the viewpoint of reducing the dielectric loss tangent of the resulting insulating layer. The resin composition may also optionally contain (b) an epoxy resin, (c) a curing agent, (d) a polymer resin, (e) a radical polymerizable resin, (f) a flame retardant, (g) a curing accelerator, (h) a radical polymerization initiator, (i) other additives, and (j) a solvent. The following describes each component that may be included in the resin composition.

[0041] In the present invention, unless otherwise specified, the content of each component in the resin composition is the value when the non-volatile component in the resin composition is taken as 100% by mass, and the non-volatile component refers to the components constituting the resin composition other than the solvent (j) described later.

[0042] -(a) Inorganic filler- The resin composition contains (a) an inorganic filler as component (a). By including (a) an inorganic filler in the resin composition, an insulating layer with a low dielectric loss tangent can be obtained. (a) The inorganic filler may be used alone or in combination of two or more types.

[0043] (a) Inorganic compounds are used as the material for the inorganic filler. Examples of inorganic filler materials include silica, alumina, aluminosilicate, 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, calcium carbonate and silica are preferred, and silica is particularly preferred. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. Spherical silica is preferred as the silica.

[0044] Examples of commercially available products of component (a) include, for example, "SP60-05", "SP507-05" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YC100C", "YA050C", "YA050C-MJE", "YA010C", "SC2500SQ", "SO-C4", "SO-C2", "SO-C1" manufactured by Admatechs Co., Ltd.; "UFP-30", "DAW-03", "FB-105FD" manufactured by Denka Co., Ltd.; "Silfill NSS-3N", "Silfill NSS-4N", "Silfill NSS-5N" manufactured by Tokuyama Corporation; "Cellspheres", "MGH-005" manufactured by Pacific Cement Co., Ltd., and the like.

[0045] The specific surface area of component (a) is preferably 1 m 2 / g or more, more preferably 2 m 2 / g or more, particularly preferably 3 m 2 / g or more. There is no particular limitation on the upper limit, but it is preferably 60 m 2 / g or less, 50 m 2 / g or less or 40 m 2 / g or less. The specific surface area is obtained by adsorbing nitrogen gas on the sample surface using a specific surface area measuring device (Macsorb HM-1210 manufactured by Mountech Co., Ltd.) in accordance with the BET method and calculating the specific surface area using the BET multipoint method.

[0046] The average particle size of component (a) is preferably 0.01 μm or more, more preferably 0.05 μm or more, still more preferably 0.1 μm or more, and preferably 5 μm or less, more preferably 4 μm or less, still more preferably 3 μm or less.

[0047] (a) The average particle size of component (a) 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 can be created using a laser diffraction-scattering particle size distribution analyzer, and the median diameter can be used as the average particle size. A sample can be prepared by weighing 100 mg of inorganic filler and 10 g of methyl ethyl ketone into a vial and dispersing them using ultrasound for 10 minutes. Using a laser diffraction-type particle size distribution analyzer, the volume-based particle size distribution of component (a) can be measured using a flow cell method with blue and red light source wavelengths, and the average particle size can be calculated as the median diameter from the obtained particle size distribution. An example of a laser diffraction-type particle size distribution analyzer is the "LA-960" manufactured by Horiba, Ltd.

[0048] (a) Component is preferably treated with a surface treatment agent from the viewpoint of improving moisture resistance and dispersibility. Examples of surface treatment agents include vinylsilane coupling agents, (meth)acrylic coupling agents, fluorine-containing silane coupling agents, aminosilane coupling agents, epoxysilane coupling agents, mercaptosilane coupling agents, silane coupling agents, alkoxysilanes, organosilazane compounds, titanate coupling agents, etc. Among these, aminosilane coupling agents are preferred from the viewpoint of obtaining the effects of the present invention in particular. Furthermore, one type of surface treatment agent may be used alone, or two or more types may be used in any combination.

[0049] Examples of commercially available surface treatment agents include Shin-Etsu Chemical Co., Ltd.'s "KBM1003" (vinyltriethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM503" (3-methacryloxypropyltriethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM403" (3-glycidoxypropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM803" (3-mercaptopropyltrimethoxysilane), and Shin-Etsu Chemical Co., Ltd.'s "KBE903" (3-aminopropyltriethoxy Examples include sisilane, Shin-Etsu Chemical Co., Ltd.'s "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "SZ-31" (hexamethyldisilazane), Shin-Etsu Chemical Co., Ltd.'s "KBM103" (phenyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM-4803" (long-chain epoxy-type silane coupling agent), Shin-Etsu Chemical Co., Ltd.'s "KBM-7103" (3,3,3-trifluoropropyltrimethoxysilane), etc.

[0050] From the viewpoint of improving the dispersibility of the inorganic filler, the degree of surface treatment with the surface treatment agent is preferably within a predetermined range. Specifically, it is preferable that the inorganic filler is surface-treated with 0.2% to 5% by mass of the surface treatment agent, preferably 0.2% to 3% by mass, and preferably 0.3% to 2% by mass, per 100% by mass of the inorganic filler.

[0051] The degree of surface treatment by a surface treatment agent can be evaluated by the amount of carbon per unit surface area of ​​the inorganic filler. From the viewpoint of improving the dispersibility of the inorganic filler, the amount of carbon per unit surface area of ​​the inorganic filler should be 0.02 mg / m². 2 The 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 the increase in the melt viscosity of the resin varnish and the melt viscosity in sheet form, 1 mg / m 2 The following is preferred: 0.8 mg / m² 2 The following is more preferable: 0.5 mg / m² 2 The following is even more preferable.

[0052] (a) The amount of carbon per unit surface area of ​​an inorganic filler can be measured after cleaning the inorganic filler with a solvent (e.g., methyl ethyl ketone (MEK)) following surface treatment. Specifically, a sufficient amount of MEK is added to the inorganic filler that has been surface-treated with a surface treatment agent, and ultrasonic cleaning is performed at 25°C for 5 minutes. After removing the supernatant and drying the solids, the amount of carbon per unit surface area of ​​the inorganic filler can be measured using a carbon analyzer. A carbon analyzer such as the "EMIA-320V" manufactured by Horiba, Ltd. can be used.

[0053] (a) The content of component (a) is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 78% by mass or more, when the nonvolatile component in the resin composition is considered to be 100% by mass, from the viewpoint of obtaining an insulating layer with a low dielectric loss tangent. The upper limit is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 88% by mass or less.

[0054] <(b) Epoxy resin> The resin composition may optionally contain (b) epoxy resin as component (b). By including (b) epoxy resin, a cured product exhibiting good mechanical strength and insulation reliability can be obtained. (b) epoxy resin may be used alone or in combination of two or more types.

[0055] (b) 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, and glycidyl ester type epoxy resin. Examples include epoxy resins, glycidylcyclohexane type epoxy resins, alkyl diglycidyl ether type epoxy resins, cresol novolac type epoxy resins, biphenyl type epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiroring-containing epoxy resins, cyclohexane type epoxy resins, cyclohexanedimethanol type epoxy resins, naphthylene ether type epoxy resins, trimethylol type epoxy resins, tetraphenylethane type epoxy resins, phenolphthaleimidine type epoxy resins, and the like. Epoxy resins may be used individually or in combination of two or more types.

[0056] The resin composition preferably contains an epoxy resin having two or more epoxy groups in one molecule as component (b). From the viewpoint of significantly obtaining the desired effects of the present invention, the ratio of the epoxy resin having two or more epoxy groups in one molecule to 100% by mass of the epoxy resin (b) is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more.

[0057] (b) 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"). The resin composition may contain only liquid epoxy resin as component (b), only solid epoxy resin, or a combination of liquid epoxy resin and solid epoxy resin.

[0058] As the liquid epoxy resin, a liquid epoxy resin having two or more epoxy groups in one molecule is preferred.

[0059] 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, glycidylamine type epoxy resin, and epoxy resin having a butadiene structure, glycidylcyclohexane type epoxy resin, phenolphthaleimidine type epoxy resin, alkyl diglycidyl ether type epoxy resin, epoxy resin having a butadiene structure, and resorcinol type epoxy resin, with bisphenol A type epoxy resin, bisphenol F type epoxy resin, and epoxy resin having a butadiene structure being more preferred.

[0060] Specific examples of liquid epoxy resins include DIC's "HP4032," "HP4032D," and "HP4032SS" (naphthalene-type epoxy resin); Mitsubishi Chemical's "828US," "jER828EL," "825," and "Epicote 828EL" (bisphenol A-type epoxy resin); Mitsubishi Chemical's "jER807" and "1750" (bisphenol F-type epoxy resin); Mitsubishi Chemical's "jER152" (phenol novolac-type epoxy resin); Mitsubishi Chemical's "630" and "630LSD" (glycidylamine-type epoxy resin); and Nippon Steel Chemical & Material's "ZX1059" (a mixture of bisphenol A-type epoxy resin and bisphenol F-type epoxy resin). Examples include "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" (epoxy resin with a butadiene structure) from Daicel Corporation; "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane type epoxy resin) from Nippon Steel Chemical & Material Co., Ltd.; "YED216D" (alkyl diglycidyl ether type epoxy resin) from Mitsubishi Chemical Corporation; "YD-8125G" (bisphenol A type epoxy resin) from Nippon Steel Chemical & Material Co., Ltd.; and "EX-201" (resorcinol type epoxy resin) from Nagase ChemteX Corporation. These can be used individually or in combination of two or more types.

[0061] As for the solid epoxy resin, a solid epoxy resin having two or more epoxy groups per molecule is preferred, a solid epoxy resin having three or more epoxy groups per molecule is more preferred, and an aromatic solid epoxy resin having three or more epoxy groups per molecule is even more preferred.

[0062] Preferred solid epoxy resins include bixylenol-type epoxy resin, naphthalene-type epoxy resin, naphthalene-type tetrafunctional 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, and tetraphenylethane-type epoxy resin, with biphenyl-type epoxy resin being more preferred.

[0063] Specific examples of solid epoxy resins include DIC's "HP4032H" (naphthalene-type epoxy resin), "HP-4700", "HP-4710" (naphthalene-type tetrafunctional epoxy resin), "N-690" (cresol novolac-type epoxy resin), "N-695" (cresol novolac-type epoxy resin), "HP-7200", "HP-7200HH", "HP-7200H" (dicyclopentadiene-type epoxy resin), and "EXA-731" 1", "EXA-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), "NC7000L" (naphthol novolac type epoxy resin), "NC3000H", "NC3000", "NC3000L", "NC3100" (biphenyl type epoxy resin); Nippon Steel Chemical & Material's "ESN475V", "ESN4100V" (naphthalene-type epoxy resin), "ESN485" (naphthol novolac-type epoxy resin), "ESN4100-VEK75" (naphthol aralkyl-type epoxy resin); Mitsubishi Chemical's "YX4000H", "YL6121" (biphenyl-type epoxy resin), "YX4000HK" (bixylenol-type epoxy resin), "YX8800" (anthracene-type epoxy resin) Examples of xylyl resins include "PG-100" and "CG-500" from Osaka Gas Chemical Co., Ltd., and "YL7760" (bisphenol AF type epoxy resin), "YL7800" (fluorene type epoxy resin), "jER1010" (solid bisphenol A type epoxy resin), and "jER1031S" (tetraphenylethane type epoxy resin) from Mitsubishi Chemical Corporation; as well as "WHR-991S" (phenolphthalein type epoxy resin) from Nippon Kayaku Co., Ltd. These may be used individually or in combination of two or more types.

[0064] (b) When a liquid epoxy resin and a solid epoxy resin are used in combination as components, their mass ratio (liquid epoxy resin:solid epoxy resin) is preferably 1:0.1 to 1:20, more preferably 1:0.15 to 1:10, and particularly preferably 1:0.2 to 1:5.

[0065] (b) The epoxy equivalent of component is preferably 50 g / eq. to 5000 g / eq., more preferably 50 g / eq. to 3000 g / eq., even more preferably 80 g / eq. to 2000 g / eq., and even more preferably 110 g / eq. to 1000 g / eq. This range ensures that the crosslinking density of the cured resin composition is sufficient to produce a cured product. The epoxy equivalent is the mass of epoxy resin containing one equivalent of epoxy groups. This epoxy equivalent can be measured according to JIS K7236.

[0066] (b) The weight-average molecular weight (Mw) of component is preferably 100 to 5000, more preferably 150 to 3000, and even more preferably 200 to 1500, from the viewpoint of significantly obtaining the desired effects of the present invention. The weight-average molecular weight of the epoxy resin is the weight-average molecular weight on a polystyrene basis, measured by gel permeation chromatography (GPC).

[0067] (b) The content of component (b) is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, when the nonvolatile components in the resin composition are considered to be 100% by mass, from the viewpoint of obtaining a cured product that exhibits good mechanical strength and insulation reliability. The upper limit is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less.

[0068] <(c) Hardener> The resin composition may optionally contain a curing agent as component (c). This curing agent as component (c) excludes those corresponding to components (a) and (b). Component (c) usually has the function of curing the resin composition by reacting with component (b). Component (c) may be used alone or in combination of two or more types in any ratio.

[0069] Component (c) can be a compound that reacts with component (b) to cure the resin composition, and examples include active ester curing agents, phenol curing agents, benzoxazine curing agents, carbodiimide curing agents, acid anhydride curing agents, amine curing agents, and cyanate ester curing agents. In particular, component (c) preferably contains any of the active ester curing agent, phenol curing agent, and carbodiimide curing agent.

[0070] Examples of active ester curing agents include those having one or more active ester groups in one molecule. Among these, compounds having two or more highly reactive ester groups in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds, are preferred as active ester curing agents. The active ester curing agent 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, an active ester curing agent obtained from a carboxylic acid compound and a hydroxy compound is preferred, and an active ester curing agent obtained from a carboxylic acid compound and a phenol compound and / or a naphthol compound is more preferred.

[0071] 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.

[0072] 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.

[0073] Preferred examples of active ester curing agents include dicyclopentadiene-type active ester curing agents, naphthalene-type active ester curing agents containing a naphthalene structure, active ester curing agents containing an acetylated phenol novolac, active ester curing agents containing a benzoylated phenol novolac, active ester curing agents that are acetylated phenol novolacs, and active ester curing agents containing a styryl group and a naphthalene structure. As for dicyclopentadiene-type active ester curing agents, active ester curing agents containing a dicyclopentadiene-type diphenol structure are preferred. "Dicyclopentadiene-type diphenol structure" refers to a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene. Among these, it is preferable to include dicyclopentadiene-type active ester curing agents as active ester curing agents.

[0074] Commercially available active ester curing agents include, as active ester curing agents containing a dicyclopentadiene-type diphenol structure, "EXB9451", "EXB9460", "EXB9460S", "HPC-8000L-65TM", "HPC-8000-65T", "EXB-8000H", and "EXB-8000L-65TM" (manufactured by DIC); and as active ester curing agents containing a naphthalene structure, "EXB-9416-70BK", "EXB-8100L-65T", "HPC-8150-62T", "EXB-8150L-65T", "EXB-8100L-65T", and "EXB-8" (manufactured by DIC). Examples of phosphorus-containing active ester curing agents include "EXB9401" (manufactured by DIC Corporation), "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester curing agent containing an acetylated phenol novolac, "YLH1026", "YLH1030", "YLH1048" (manufactured by Mitsubishi Chemical Corporation) and "EXB-8500-65T" (manufactured by DIC Corporation) as active ester curing agents containing a styryl group and a naphthalene structure include "PC1300-02-65T" and "PC1300-02-65MA" (manufactured by Air Water Corporation).

[0075] Examples of phenolic curing agents include those having one or more, preferably two or more, hydroxyl groups bonded to aromatic rings (benzene rings, naphthalene rings, etc.) per molecule. Among these, compounds having hydroxyl groups bonded to benzene rings are preferred. Furthermore, from the viewpoint of heat resistance and water resistance, phenolic curing agents having a novolac structure are preferred. Moreover, from the viewpoint of adhesion, nitrogen-containing phenolic curing agents are preferred, and triazine skeleton-containing phenolic curing agents are more preferred. In particular, from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion, triazine skeleton-containing phenol novolac curing agents are preferred.

[0076] Specific examples of phenol-based and naphthol-based curing agents include "MEH-7700," "MEH-7810," 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-495," "SN-495V," "SN-375," and "SN-395" from Nippon Steel Chemical & Material Co., Ltd. Examples include DIC Corporation's "TD-2090", "TD-2090-60M", "LA-7052", "LA-7054", "LA-1356", "LA-3018", "LA-3018-50P", "EXB-9500", "HPC-9500", "KA-1160", "KA-1163", and "KA-1165"; and Gun-ei Chemical Co., Ltd.'s "GDP-6115L", "GDP-6115H", and "ELPC75".

[0077] Specific examples of carbodiimide-based curing agents include "V-03," "V-05," "V-07," and "V-11S" manufactured by Nisshinbo Chemical Co., Ltd., and Stavaxol® P manufactured by Rhein Chemie Co., Ltd.

[0078] Specific examples of benzoxazine-based curing agents include "ODA-BOZ" from JFE Chemical Corporation, "HFB2006M" from Showa Polymer Co., Ltd., and "Pd" and "Fa" from Shikoku Chemicals Co., Ltd.

[0079] Examples of acid anhydride-based curing agents include those having one or more acid anhydride groups in one molecule. Specific examples of acid anhydride-based curing agents include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, 4-methylhexahydrophthalic 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 benzophenone. Examples of acid anhydrides include tetracarboxylic dianhydrides, biphenyltetracarboxylic dianhydrides, naphthalenetetracarboxylic dianhydrides, oxydiphthalic acid dianhydrides, 3,3'-4,4'-diphenylsulfonetetracarboxylic dianhydrides, 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. Commercially available acid anhydride-based curing agents may also be used, such as "MH-700" manufactured by Shin Nippon Rika Co., Ltd.

[0080] Examples of amine-based curing agents include curing agents having one or more amino groups in one molecule, such as aliphatic amines, polyetheramines, alicyclic amines, and aromatic amines. Among these, aromatic amines are preferred from the viewpoint of achieving the desired effects of the present invention. The amine-based curing agent is preferably a primary amine or a secondary amine, and more preferably a primary amine. Specific examples of amine-based curing agents include 4,4'-methylenebis(2,6-dimethylaniline), diphenyldiaminosulfone, 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-hydroxy Examples include bis(4-(4-aminophenoxy)phenyl)propane, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethanediamine, 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. Commercial amine-based curing agents may also be used, such as "KAYABOND C-200S", "KAYABOND C-100", "KAYAHARD AA", "KAYAHARD AB", and "KAYAHARD AS" from Nippon Kayaku Co., Ltd., and "Epicure W" from Mitsubishi Chemical Corporation.

[0081] Examples of cyanate ester curing agents include bifunctional cyanate resins such as bisphenol A dicyanate, polyphenol cyanate, oligo(3-methylene-1,5-phenylene cyanate), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-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 resins derived from phenol novolacs and cresol novolacs, etc.; and prepolymers in which these cyanate resins are partially triazined. Specific examples of cyanate ester curing agents include "PT30" and "PT60" (both phenol novolac type polyfunctional cyanate ester resins) manufactured by Lonza Japan Co., Ltd.; "ULL-950S" (polyfunctional cyanate ester resin); "BA230" and "BA230S75" (prepolymers in which part or all of bisphenol A dicyanate is triazined and trimerized); and others.

[0082] (b) When the number of epoxy groups in component (b) is set to 1, the number of active groups in the curing agent (c) is preferably 0.01 or more, more preferably 0.05 or more, even more preferably 0.1 or more, preferably 10 or less, more preferably 5 or less, and even more preferably 3 or less. Here, "number of epoxy groups in component (b)" is the sum of all values ​​obtained by dividing the mass of the nonvolatile components of component (b) present in the resin composition by the epoxy equivalent. Also, "number of active groups in the curing agent (c)" is the sum of all values ​​obtained by dividing the mass of the nonvolatile components of the curing agent (c) present in the resin composition by the active group equivalent.

[0083] (c) The content of the curing agent is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 3% by mass or more, preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less, when the nonvolatile components in the resin composition are taken as 100% by mass.

[0084] <(d) Polymer resin> The resin composition may optionally contain, as component (d), a polymer resin (d). This polymer resin (d) as component (d) does not include those corresponding to components (a) to (c) described above. The polymer resin (d) may be used alone or in combination of two or more types.

[0085] (d) The polymer resin typically has a weight-average molecular weight greater than that of (b) the epoxy resin, and can exert the effect of reducing the elastic modulus of the cured resin composition. The specific weight-average molecular weight of (d) the polymer resin is typically greater than 5,000, preferably 8,000 or more, more preferably 10,000 or more, even more preferably 20,000 or more, particularly preferably 30,000 or more, preferably 100,000 or less, more preferably 70,000 or less, particularly preferably 60,000 or less.

[0086] (d) Examples of polymer resins include (d-1) elastomers. (d-1) elastomers do not include those corresponding to components (a) to (c) described above. (d-1) elastomers may be used individually or in combination of two or more types.

[0087] (d-1) As elastomers, compounds having one or more structures selected from polybutadiene, polysiloxane, poly(meth)acrylate, polyalkylene, polyalkylene oxy, polyisoprene, polyisobutylene, polyester, and polycarbonate structures within the molecule are preferred. More preferably, compounds having one or more structures selected from the group consisting of polybutadiene, poly(meth)acrylate, polyalkylene oxy, polyisoprene, polyester, and polycarbonate structures within the molecule are preferred. Furthermore, compounds having one or more structures selected from the group consisting of polybutadiene, polyester, and polycarbonate structures within the molecule are particularly preferred. "(meth)acrylate" is a term that includes methacrylate and acrylate, as well as combinations thereof. These structures may be included in the main chain or side chain of the elastomer molecule.

[0088] (d-1) An example of an elastomer is a resin containing a polybutadiene structure. The polybutadiene structure may be included in the main chain or in the side chain. The polybutadiene structure may be partially or entirely hydrogenated. A resin containing a polybutadiene structure is sometimes called a polybutadiene resin. 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" (acid anhydride group-containing polybutadiene); Nippon Soda's "GQ-1000" (hydroxyl group and carboxyl group-introduced polybutadiene), "G-1000," "G-2000," and "G-3000" (hydroxyl group polybutadiene at both ends), "GI-1000," "GI-2000," and "GI-3000" (hydroxyl group hydrogenated polybutadiene at both ends); and Nagase ChemteX's "FCA-061L" (hydrogenated polybutadiene skeleton epoxy resin). Examples of polybutadiene resins include hydroxyl-terminated polybutadiene, diisocyanate compounds, and linear polyimides derived from tetrabasic acid anhydrides (polyimides described in Japanese Patent Publication No. 2006-37083 and International Publication No. 2008 / 153208), and phenolic hydroxyl-containing butadiene. The butadiene structure content of 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 Japanese Patent Publication No. 2006-37083 and International Publication No. 2008 / 153208, and this information is incorporated herein by reference.

[0089] (d-1) Another example of an elastomer is a resin containing a poly(meth)acrylate structure. Resins containing a poly(meth)acrylate structure are sometimes called poly(meth)acrylic resins. Examples of poly(meth)acrylic resins include Teisan Resin from Nagase ChemteX Corporation and "ME-2000", "W-116.3", "W-197C", "KG-25", and "KG-3000" from Negami Kogyo Co., Ltd.

[0090] (d-1) Another example of an elastomer is a resin containing a polycarbonate structure. A resin containing a polycarbonate structure is sometimes called a polycarbonate resin. Examples of polycarbonate resins include "T6002" and "T6001" (polycarbonate diols) from Asahi Kasei Corporation, and "C-1090," "C-2090," and "C-3090" (polycarbonate diols) from Kuraray Co., Ltd. Linear polyimides made from hydroxyl-terminated polycarbonates, diisocyanate compounds, and tetrabasic acid anhydrides can also be used. The content of 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.

[0091] (d-1) Another example of an elastomer is a resin containing a polysiloxane structure. Resins containing a polysiloxane structure are sometimes called siloxane resins. Examples of siloxane resins include "SMP-2006", "SMP-2003PGMEA", and "SMP-5005PGMEA" manufactured by Shin-Etsu Silicone Co., Ltd., as well as linear polyimides made from amine-terminated polysiloxanes and tetrabasic acid anhydrides (International Publication No. 2010 / 053185, Japanese Patent Publication No. 2002-12667 and Japanese Patent Publication No. 2000-319386, etc.).

[0092] (d-1) Another example of an elastomer is a resin containing a polyalkylene structure or a polyalkylene oxy structure. A resin containing a polyalkylene structure is sometimes called a polyalkylene resin, and a resin containing a polyalkylene oxy structure is sometimes called a polyalkylene oxy resin. The polyalkylene oxy structure preferably has 2 to 15 carbon atoms, more preferably has 3 to 10 carbon atoms, and even more preferably has 5 to 6 carbon atoms. Specific examples of polyalkylene resins and polyalkylene oxy resins include "PTXG-1000" and "PTXG-1800" manufactured by Asahi Kasei Fibers Co., Ltd.

[0093] (d-1) Another example of an elastomer is a resin containing a polyisoprene structure. A resin containing a polyisoprene structure is sometimes called a polyisoprene resin. Examples of polyisoprene resins include "KL-610" and "KL613" manufactured by Kuraray Co., Ltd.

[0094] (d-1) Another example of an elastomer is a resin containing a polyisobutylene structure. A resin containing a polyisobutylene structure is sometimes called a polyisobutylene resin. Examples of polyisobutylene resins include Kaneka's "SIBSTAR-073T" (styrene-isobutylene-styrene triblock copolymer) and "SIBSTAR-042D" (styrene-isobutylene diblock copolymer).

[0095] (d-1) Another example of an elastomer is a resin containing a polyester structure. A resin containing a polyester structure is sometimes called a polyester resin. Examples of polyester resins include "Byron 600", "Byron 560", "Byron 230", "Byron GK-360", and "Byron BX-1001" from Toyobo Co., Ltd., and "LP-035", "LP-011", "TP-220", "TP-249", and "SP-185" from Mitsubishi Chemical Corporation.

[0096] (d-1) The elastomer may have a functional group that can react with (b) the epoxy resin. The functional group that can react with (b) the epoxy resin includes a functional group that appears upon heating. In one embodiment, the functional group that can react with (b) the epoxy resin may be one or more functional groups selected from the group consisting of a hydroxyl group, a carboxyl group, an acid anhydride group, a phenolic hydroxyl group, an epoxy group, an isocyanate group, and a urethane group. Among these, the functional group is preferably a hydroxyl group, an acid anhydride group, a phenolic hydroxyl group, an epoxy group, an isocyanate group, and a urethane group, more preferably a hydroxyl group, and particularly preferably a phenolic hydroxyl group. However, when the functional group includes an epoxy group, the weight-average molecular weight (Mw) of the (d-1) elastomer is preferably 5,000 or more.

[0097] (d-1) The elastomer preferably has a large number-average molecular weight. The specific number-average molecular weight (Mn) of the (d-1) elastomer is preferably 1,000 or more, more preferably 1,500 or more, even more preferably 3,000 or more, and particularly preferably 5,000 or more. The upper limit is preferably 1,000,000 or less, and more preferably 900,000 or less. The number-average molecular weight (Mn) is the number-average molecular weight on a polystyrene basis measured using GPC (gel permeation chromatography).

[0098] (d-1) The elastomer preferably has a low glass transition temperature (Tg). The specific glass transition temperature (Tg) of the (d-1) elastomer is preferably 30°C or lower, more preferably 20°C or lower, even more preferably 10°C or lower, preferably -60°C or higher, more preferably -50°C or higher, and even more preferably -45°C or higher.

[0099] (d) Examples of polymer resins include (d-2) thermoplastic resins. (d-2) Thermoplastic resins do not include the components (a) to (c) described above, nor those corresponding to (d-1) elastomers. (d-2) Thermoplastic resins may be used individually or in combination of two or more types.

[0100] (d-2) Examples of thermoplastic resins include phenoxy resin, polyvinyl acetal resin, polyolefin resin, polyimide resin, polyamide-imide resin, polyetherimide resin, polysulfone resin, polyethersulfone resin, polyphenylene ether resin, polyetheretherketone resin, polyester resin, etc. (d-2) A single thermoplastic resin may be used, or two or more types may be used in combination. (d-2) Among thermoplastic resins, phenoxy resin is preferred.

[0101] 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.

[0102] Specific examples of polyimide resins include "PIAD200" manufactured by Arakawa Chemical Co., Ltd., "SLK-6100" manufactured by Shin-Etsu Chemical Co., Ltd., and "Ricacoat SN20" and "Ricacoat PN20" manufactured by Shin-Nippon Rika Co., Ltd. Specific examples of these polyimide resins also include modified polyimide resins such as linear polyimide resins obtained by reacting a bifunctional hydroxyl-terminated polybutadiene, a diisocyanate compound, and a tetrabasic acid anhydride (polyimide resin described in Japanese Patent Publication No. 2006-37083), and polysiloxane skeleton-containing polyimide resins (polyimide resins described in Japanese Patent Publication No. 2002-12667 and Japanese Patent Publication No. 2000-319386, etc.).

[0103] 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.

[0104] 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.

[0105] 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 Resonaq Corporation.

[0106] Specific examples of polyethersulfone resins include "PES5003P" manufactured by Sumitomo Chemical Co., Ltd.

[0107] Specific examples of polysulfone resins include Solvay Advanced Polymers' polysulfones "P1700" and "P3500".

[0108] The polyphenylene ether resin may be a copolymer of polyphenylene ether and polybutadiene. Specific examples of polyetherimide resins include GE's "Ultem," among others.

[0109] (d-2) The weight-average molecular weight (Mw) of the thermoplastic resin is preferably 8,000 or more, more preferably 10,000 or more, particularly preferably 20,000 or more, preferably 70,000 or less, more preferably 60,000 or less, and particularly preferably 50,000 or less, from the viewpoint of significantly obtaining the desired effects of the present invention.

[0110] (d) The polymer resin content 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 4% by mass or less, and even more preferably 3% by mass or less, when the resin components of the resin composition are taken as 100% by mass.

[0111] <(e) Radical polymerizable resins> The resin composition may optionally contain, as component (e), a radical polymerizable resin. This radical polymerizable resin as component (e) does not include those corresponding to components (a) to (d) described above. A radical polymerizable resin means a resin having one or more (preferably two or more) radical polymerizable unsaturated groups per molecule. The radical polymerizable resin (e) may be used alone or in combination of two or more types.

[0112] Examples of radically polymerizable unsaturated groups include one or more selected from maleimide group, vinyl group, allyl group, styryl group, vinylphenyl group, acryloyl group, methacryloyl group, fumaroyl group, and maleoil group. In particular, it is preferable that the radically polymerizable unsaturated group has any of the maleimide group, vinyl group, styryl group, acryloyl group, and methacryloyl group, and more preferably either the maleimide group or the styryl group. Therefore, from the viewpoint of significantly obtaining the effects of the present invention, the radically polymerizable resin is more preferably a maleimide resin, a (meth)acrylic resin, or a vinyl resin.

[0113] The type of maleimide resin is not particularly limited, as long as it has one or more (preferably two or more) maleimide groups (2,5-dihydro-2,5-dioxo-1H-pyrrole-1-yl groups) per molecule. Examples of maleimide resins include (1) "BMI-3000J", "BMI-5000", "BMI-1400", "BMI-1500", "BMI-1700", and "BMI-689" (all from Designer Molecules). Examples include maleimide resins containing an aliphatic skeleton (preferably an aliphatic skeleton with 36 carbon atoms derived from dimeramine), such as "SLK6895-T90" (manufactured by Shin-Etsu Chemical Co., Ltd.) and "BMI-TMH" (manufactured by Yamato Chemical Co., Ltd.); (2) Maleimide resins containing an indan skeleton as described in the Japan Institute of Invention and Innovation, Technical Report No. 2020-500211; and (3) Maleimide resins containing an aromatic ring skeleton directly bonded to the nitrogen atom of the maleimide group, such as "MIR-3000-70MT" and "MIR-5000-60T" (both manufactured by Nippon Kayaku Co., Ltd.), "BMI-4000" and "BMI-2300" (both manufactured by Yamato Chemical Co., Ltd.), and "BMI-70" and "BMI-80" (both manufactured by Kei-I Chemical Co., Ltd.).

[0114] The type of (meth)acrylic resin is not particularly limited as long as it has one or more (preferably two or more) (meth)acryloyl groups in one molecule, and may be a monomer or oligomer. Here, the term "(meth)acryloyl group" is a general term for acryloyl groups and methacryloyl groups. Examples of methacrylic resins include (meth)acrylate monomers, as well as (meth)acrylic resins such as "A-DOG" (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), "DCP-A" (manufactured by Kyoeisha Chemical Co., Ltd.), "SA9000" (manufactured by SABIC Corporation), "NPDGA", "FM-400", "R-604", "R-684", "THE-330", "PET-30", "DPHA", and "DPCA" (all manufactured by Nippon Kayaku Co., Ltd.).

[0115] The type of vinyl resin is not particularly limited, as long as it has one or more (preferably two or more) vinyl groups in one molecule. A vinyl resin may also be called a styrene resin if it has a styryl group having one or more, preferably two or more vinyl groups directly bonded to an aromatic carbon atom. Examples of vinyl 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; high molecular weight (molecular weight 1000 or more) styrene resins such as vinylbenzyl-modified polyphenylene ether resins and styrene-divinylbenzene copolymers; and styrene compounds having either a phenylpyrimidine skeleton or a 1,1-diphenylcyclohexane skeleton. Examples of commercially available vinyl resins and styrene 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.

[0116] (e) The content of the radical polymerizable resin may be 0% by mass, preferably 0.01% by mass or more, more preferably 0.05% 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, when the nonvolatile components in the resin composition are taken as 100% by mass.

[0117] <(f) Flame retardant> The resin composition may optionally contain a flame retardant as component (f). This flame retardant as component (f) does not include those corresponding to components (a) to (e) described above. Component (f) may be used alone or in combination of two or more types.

[0118] (f) Examples of flame retardants include phosphazene compounds, organophosphorus flame retardants, organic nitrogen-containing phosphorus compounds, nitrogen compounds, silicone flame retardants, and metal hydroxides.

[0119] The phosphazene compound is not particularly limited as long as it is a cyclic compound with nitrogen and phosphorus as constituent elements.

[0120] Specific examples of phosphazene compounds include, for example, "SPH-100," "SPS-100," "SPB-100," and "SPE-100" manufactured by Otsuka Chemical Co., Ltd., and "FP-100," "FP-110," "FP-300," and "FP-400" manufactured by Fushimi Pharmaceutical Co., Ltd., with "SPH-100" manufactured by Otsuka Chemical Co., Ltd. being preferred.

[0121] As a flame retardant other than a phosphazene compound, commercially available products may be used, such as "HCA-HQ" manufactured by Sanko Co., Ltd. and "PX-200" manufactured by Daihachi Chemical Industry Co., Ltd. As a flame retardant, one that is not easily hydrolyzed is preferred, such as 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0122] (f) The flame retardant content is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, even more preferably 0.5% 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, when the nonvolatile components in the resin composition are taken as 100% by mass.

[0123] <(g) Curing accelerator> The resin composition may contain (g) a curing accelerator as an optional component. The curing accelerator as component (g) does not include any of the components (a) to (f) described above. The curing accelerator (g) can act as a catalyst in the reaction of (b) the epoxy resin to accelerate the curing of the resin composition.

[0124] (g) Examples of curing accelerators include phosphorus-based curing accelerators, urea-based curing accelerators, guanidine-based curing accelerators, imidazole-based curing accelerators, metal-based curing accelerators, amine-based curing accelerators, etc. (g) A single type of curing accelerator may be used alone, or two or more types may be used in combination.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] (g) The content of the curing accelerator is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, even more preferably 0.01% by mass or more, preferably 0.5% by mass or less, more preferably 0.3% by mass or less, and even more preferably 0.1% by mass or less, based on 100% by mass of the nonvolatile components in the resin composition.

[0132] <(h) Radical polymerization initiator> The resin composition may contain an optional component, which is a radical polymerization initiator (h). This radical polymerization initiator (h) as component (h) excludes those corresponding to components (a) to (g). The radical polymerization initiator (h) may be, for example, a thermal polymerization initiator that generates free radicals when heated. The radical polymerization initiator (h) may be a polymerization initiator of a radical reactive group. The radical polymerization initiator (h) may be used alone or in any combination of two or more types.

[0133] (h) Examples of radical polymerization initiators include peroxide-based radical polymerization initiators and azo-based radical polymerization initiators.

[0134] Examples of peroxide-based radical polymerization initiators include hydroperoxide compounds such as 1,1,3,3-tetramethylbutyl hydroperoxide; dialkylperoxide compounds such as tert-butylcumyl peroxide, di-tert-butyl peroxide, di-tert-hexyl peroxide, dicumyl peroxide, 1,4-bis(1-tert-butylperoxy-1-methylethyl)benzene, and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; and diacylperoxide compounds such as dilauroyl peroxide, didecanoyl peroxide, dicyclohexyl peroxydicarbonate, and bis(4-tert-butylcyclohexyl) peroxydicarbonate. Examples of peroxyester compounds include tert-butyl peroxyacetate, tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl monocarbonate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxyneodecanoate, tert-hexyl peroxyisopropyl monocarbonate, tert-butyl peroxylaurate, (1,1-dimethylpropyl)2-ethyl perhexanoate, tert-butyl 2-ethyl perhexanoate, tert-butyl 3,5,5-trimethyl perhexanoate, tert-butyl peroxy-2-ethylhexyl monocarbonate, tert-butyl peroxymaleic acid, and others.

[0135] Examples of azo radical polymerization initiators include azonitrile compounds such as 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitride), 1-[(1-cyano-1-methylethyl)azo]formamide, and 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile; 2,2'-azobis[2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide], and 2,2'-azobis[2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide]. Examples include azoamide compounds such as methyl)ethyl[propionamide], 2,2'-azobis[2-methyl-N-[2-(1-hydroxybutyl)]-propionamide], 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)-propionamide], 2,2'-azobis(2-methylpropionamide) dihydrate, 2,2'-azobis[N-(2-propenyl)-2-methylpropionamide], 2,2'-azobis(N-butyl-2-methylpropionamide), and 2,2'-azobis(N-cyclohexyl-2-methylpropionamide); and alkylazo compounds such as 2,2'-azobis(2,4,4-trimethylpentane) and 2,2'-azobis(2-methylpropane).

[0136] (h) Examples of commercially available radical polymerization initiators include NOF Corporation's "Perbutyl C", "Perbutyl A", "Perbutyl P", "Perbutyl L", "Perbutyl O", "Perbutyl ND", "Perbutyl Z", "Perbutyl I", "Permil P", "Permil D", "Perhexyl D", "Perhexyl A", "Perhexyl I", "Perhexyl Z", "Perhexyl ND", "Perhexyl O", and "Perhexyl PV".

[0137] The content of component (h) is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, even more preferably 0.01% by mass or more, preferably 0.5% by mass or less, more preferably 0.3% by mass or less, and even more preferably 0.1% by mass or less, when the nonvolatile components in the resin composition are taken as 100% by mass.

[0138] <(i) Other additives> In addition to the components described above, the resin composition may further contain (i) other additives as non-volatile components. Examples of such additives include: 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; defoaming agents such as silicone-based defoaming agents, acrylic-based defoaming agents, fluorine-based defoaming agents, and vinyl resin-based defoaming agents; ultraviolet absorbers such as benzotriazole-based ultraviolet absorbers; and urea. Examples of other additives include adhesion enhancers such as ran; adhesion enhancers such as triazole-based adhesion enhancers, tetrazole-based adhesion enhancers, and triazine-based adhesion enhancers; 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. (i) Other additives may be used individually or in combination of two or more in any ratio. (i) The content of other additives can be appropriately determined by a person skilled in the art.

[0139] <(j) Solvent> The resin composition may contain, in addition to the non-volatile components described above, any solvent as a volatile component. (j) Any known solvent can be used as appropriate, and the type is not particularly limited, but an organic solvent is preferred. (j) Examples of solvents include: ketone solvents such as acetone, methyl ethyl ketone (MEK), 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 methoxypropio Examples include ether ester solvents such as methyl phosphate; 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. (j) The solvent may be used alone or in combination of two or more in any ratio.

[0140] The method for preparing the resin composition is not particularly limited, and examples include mixing and dispersing the constituent components using a rotary mixer or the like, with the addition of a solvent as necessary.

[0141] The curing shrinkage rate of the cured product obtained by curing the resin composition layer at 200°C for 90 minutes is preferably 0.20% or less, more preferably 0.18% or less, even more preferably 0.17% or less, 0.16% or less, 0.15% or less, 0.10% or less, 0.09% or less, or 0.08% or less, from the viewpoint of improving embedding ability. There is no particular lower limit, but it may be 0% or more, or 0.01% or more, etc. The curing shrinkage rate can be measured according to the method described in the examples below.

[0142] The thickness of the resin composition layer is preferably greater than 100 μm, more preferably 110 μm or more, even more preferably 120 μm or more, or 130 μm or more, preferably 500 μm or less, more preferably 450 μm or less, even more preferably 400 μm or less, or 350 μm or less, from the viewpoint of embedding tall conductive pillars.

[0143] <Any layer> The resin sheet may further include any additional layers in combination with the support and the resin composition layer, as needed. Examples of such additional layers include a protective film provided on the side of the 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, it can suppress the adhesion of dust and scratches to the surface of the resin composition layer.

[0144] <Method for manufacturing resin sheets> A resin sheet can be manufactured, for example, by a method that includes forming a resin composition layer containing a resin composition on a support. One embodiment of a method for manufacturing a resin sheet includes, in this order, the steps of: preparing a resin varnish containing a resin composition; applying the resin varnish to a support; and drying the applied resin varnish to form a resin composition layer.

[0145] Resin varnish may be manufactured by mixing components and solvents that may be included in the resin composition. As the solvent for the resin varnish, the solvent (j) described above may be used. Each component may be mixed partially or entirely at the same time, or 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.

[0146] The resin varnish can be applied using a coating device such as a die coater. Drying can be carried out by methods such as heating or hot air blowing, but drying by heating is preferred.

[0147] The drying temperature varies depending on the components contained in the resin composition, but is usually around 115°C, preferably 70°C or higher, more preferably 80°C or higher, even more preferably 90°C or higher, or 100°C or higher, preferably 150°C or lower, more preferably 140°C or lower, and even more preferably 130°C or lower.

[0148] The drying time is preferably 1 minute or more, more preferably 1.5 minutes or more, even more preferably 2 minutes or more, preferably 10 minutes or less, more preferably 8 minutes or less, and even more preferably 7 minutes or less.

[0149] The content of (j) solvent in the resin composition layer after drying the resin varnish is preferably 8% by mass or less, more preferably 5% by mass or less, even more preferably 3.5% by mass or less, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 0.8% by mass or more, based on 100% by mass of the total components of the resin composition layer.

[0150] The resin sheet can be stored by rolling it up. If the resin sheet has a protective film, it can be used after removing the protective film.

[0151] A cured product obtained by heat-curing a resin composition at 130°C for 30 minutes, followed by 200°C for 90 minutes, typically exhibits a low dielectric loss tangent. A resin composition layer with a thickness of 40 μm is heat-cured at 130°C for 30 minutes, followed by 200°C for 90 minutes to obtain a cured product for evaluation. The cured product for evaluation is cut to a predetermined size, and the dielectric loss tangent is measured three times using the cavity resonance perturbation method at a measurement frequency of 5.8 GHz and a measurement temperature of 23°C. The average value of the dielectric loss tangent at this time is preferably 0.01 or less, more preferably 0.009 or less, even more preferably 0.008 or less, 0.007 or less, 0.006 or less, or 0.005 or less. The lower limit is not particularly limited, but can be 0.0001 or more. The dielectric loss tangent can be measured by the method described in the examples below.

[0152] Since the resin sheet uses a support with an elongation ratio (A / B) of less than 1.30, the variation in the thickness of the resin composition layer is small. The variation in the thickness of the resin composition layer can be evaluated by dividing the film thickness tolerance of the resin composition layer in the resin sheet by the thickness of the resin composition layer. The smaller this value, the smaller the variation in the thickness of the resin composition layer. The value obtained by dividing the film thickness tolerance by the thickness of the resin composition layer is preferably 0.18 or less, more preferably 0.17 or less, even more preferably 0.16 or less, 0.15 or 0.13 or less. There is no particular lower limit, but it is preferably 0 or more, more preferably 0.03 or more, even more preferably 0.05 or more, or 0.07 or more. The value obtained by dividing the film thickness tolerance by the thickness of the resin composition layer can be evaluated by the method described in the examples below. Here, "film thickness tolerance" refers to the measured value of the film thickness obtained by subtracting the minimum value from the maximum value of the film thickness of the resin composition layer.

[0153] [Manufacturing method for package substrates] The method for manufacturing a package substrate of the present invention is as follows: (A) A step of preparing a resin sheet comprising a support and a resin composition layer provided on the support containing a resin composition, (B) A step of laminating a resin composition layer of a resin sheet onto a substrate on which conductive pillars are provided on the surface, so as to embed the conductive pillars. (C) A step of curing the resin composition layer to form an insulating layer, and (D) The process includes polishing the surface of the insulating layer to expose the conductor pillars.

[0154] As mentioned above, if there is variation in the thickness of the resin composition layer of the resin sheet, the thinner parts of the resin composition layer may not be able to completely embed the conductor pillars, resulting in voids between the conductor pillars and the insulating layer, and thus poor embedding performance. Furthermore, if there is variation in the thickness of the resin composition layer of the resin sheet, when polishing the insulating layer, some areas of the conductor pillars will be exposed while others will not. If polishing continues to expose all the conductor pillars, the already exposed conductor pillars may be polished along with the insulating layer, causing dragging.

[0155] In this invention, a package substrate is manufactured using a resin sheet equipped with a support having an elongation ratio (A / B) of less than 1.30. Such a support is less prone to stretching and shrinking when heated. Therefore, when manufacturing the resin sheet, the elongation of the support during heating and drying when forming the resin composition layer, and the shrinkage of the support after heating and drying are suppressed, and as a result, variations in the thickness of the resin composition layer are suppressed. By using a resin sheet with such suppressed variations in the resin composition layer, embedding properties and drag can be suppressed. Furthermore, this invention can also be used to manufacture a package substrate having an insulating layer that typically has excellent dielectric loss tangent.

[0156] The method for manufacturing the package substrate of the present invention is preferably carried out in the order of steps (A), (B), (C), and (D). Each step will be described below.

[0157] <Process (A)> Process (A) is the process of preparing the resin sheet, and the resin sheet is as described above.

[0158] <Process (B)> Step (B) involves laminating a resin composition layer of a resin sheet onto a substrate having multiple conductive pillars on its surface, such that the conductive pillars are embedded within the resin. The conductive pillars are primarily provided for interlayer connection.

[0159] As long as conductive pillars are provided on the surface of the substrate, any substrate used in the manufacture of package substrates may be used.

[0160] Examples of substrates include glass epoxy substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates, which are commonly used as core materials in the manufacture of circuit boards. Furthermore, the substrate may have a conductive layer on one or both sides, and this conductive layer may be patterned.

[0161] Furthermore, any substrate selected from metal substrates, inorganic substrates, and organic substrates may be used as the base material, and a metal-layered substrate may be used, in which a metal layer is provided on the surface of these substrates to function as a plating seed layer when forming conductive pillars.

[0162] Regarding the metal substrate, examples of its constituent materials (metallic materials) include copper, aluminum, and alloys of these with other metals (e.g., tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.).

[0163] Examples of inorganic substrates include glass substrates, ceramic substrates, and semiconductor wafers, while examples of organic substrates include substrates made of plastic materials. The material of the glass substrate is not particularly limited, and various glass materials such as borosilicate glass, quartz glass, lead glass, and soda-lime glass may be used. The material of the ceramic substrate is not particularly limited, and various ceramic materials such as alumina and zirconia may be used. Silicon (Si) wafers are preferred as semiconductor wafers, but are not limited thereto, and wafers such as gallium arsenide (GaAs), indium phosphide (InP), gallium phosphide (GaP), gallium nitride (GaN), gallium tellurium (GaTe), zinc selenium (ZnSe), and silicon carbide (SiC) wafers may be used. Examples of plastic materials include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), acrylics such as polycarbonate (PC) and polymethyl methacrylate (PMMA), cyclic polyolefins, triacetylcellulose (TAC), polyether sulfide (PES), polyether ketones, and polyimides. Composite materials such as fiber-reinforced plastics may also be used.

[0164] When a substrate with a metal layer is used as the base material, the metal material constituting the metal layer is not particularly limited as long as a conductive layer can be formed on the surface of the metal layer, but examples include copper, palladium, gold, platinum, silver, aluminum, and alloys of these with other metals (e.g., tin, chromium, magnesium, nickel, zirconium, silicon, titanium, etc.). The metal layer on the base material can be formed by methods such as sputtering, electroless plating, or lamination of ultrathin metal foil.

[0165] The base material is provided with conductive pillars on its surface. The conductive pillars preferably contain one or more metals selected from the group consisting of copper (Cu), gold, platinum, palladium, silver, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. The conductive pillars may be single metals or alloys, and examples of alloys include nickel-chromium alloys, copper-nickel alloys, and copper-titanium alloys. Among these, single metals are preferred for the conductive pillars, and copper is more preferred.

[0166] The conductor pillar may be a single-layer structure, or it may be a multi-layer structure in which two or more single-metal layers or alloy layers made of different types of metals or alloys are laminated. When the conductor pillar has a multi-layer structure, the layer in contact with the insulating layer is preferably a single-metal layer of chromium, zinc, or titanium, or an alloy layer of nickel-chromium alloy.

[0167] Examples of cross-sectional shapes perpendicular to the direction in which the conductor pillar extends include circular, elliptical, and rectangular shapes, with a circular shape being preferred. When the cross-sectional shape is circular, the pillar diameter is preferably 1 μm or more, more preferably 3 μm or more, even more preferably 5 μm or more, preferably 500 μm or less, more preferably 400 μm or less, and even more preferably 300 μm or less.

[0168] The height of the conductor pillar can be appropriately changed depending on the size of the package substrate, for example, preferably 70 μm or more, more preferably 80 μm or more, even more preferably 90 μm or more, 100 μm or more, 110 μm or more, or 120 μm or more, preferably 500 μm or less, more preferably 450 μm or less, even more preferably 400 μm or less, or 350 μm or less.

[0169] The distance between the conductor pillars can be appropriately changed depending on the size of the package substrate, for example, preferably 300 μm or less, more preferably 250 μm or less, even more preferably 200 μm or less, preferably 50 μm or more, more preferably 100 μm or more, and even more preferably 150 μm or more.

[0170] The formation of conductive pillars on a substrate with conductive pillars on its surface may be carried out by a so-called semi-additive method. Specifically, a photoresist (plating resist) is formed on a plating seed layer formed on the substrate, exposing a portion of the plating seed layer corresponding to a desired wiring pattern. Next, conductive pillars are formed on the exposed plating seed layer by electroplating, and then the photoresist is removed. After that, the unnecessary plating seed layer other than the areas where the conductive pillars were formed is removed by etching or the like to form a substrate with conductive pillars on its surface.

[0171] The plating seed layer formed on the substrate may be formed by dry plating or by wet plating. Examples of dry plating include physical vapor deposition (PVD) methods such as sputtering, ion plating, and vacuum deposition, and chemical vapor deposition (CVD) methods such as thermal CVD and plasma CVD. Examples of wet plating include electroless plating.

[0172] Conventional photoresists (plating resists) may be used, and either film-type photoresists (dry film photoresists) or liquid photoresists may be used.

[0173] Furthermore, a substrate with conductive pillars on its surface may also have conductive circuits on its surface in addition to the conductive pillars. The conductive material used for the conductive circuits is not particularly limited, but may be the same material as the conductive pillars. The conductive circuits may be formed in accordance with known circuit formation methods such as the semi-additive method or the fully additive method.

[0174] Lamination of a resin sheet with a substrate having conductive pillars on its surface (hereinafter sometimes simply referred to as "substrate") is not particularly limited as long as the resin composition layer can be laminated so as to embed the conductive pillars. For example, this can be done by heating and pressing the resin sheet from the support side to the side of the substrate where the conductive pillars are provided. Examples of a member for heating and pressing the resin sheet to the substrate (hereinafter also referred to as "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 via an elastic material such as heat-resistant rubber, rather than directly pressing the heat-pressing member onto the resin sheet, so that the resin sheet can adequately follow the surface irregularities of the substrate based on the conductive pillars.

[0175] The lamination of resin sheets may be carried out by a vacuum lamination method. In the vacuum lamination method, the heat-pressure temperature is preferably in the range of 60°C to 160°C, more preferably in the range of 80°C to 140°C, the heat-pressure 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, and the heat-pressure 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. Lamination may be carried out by a 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.

[0176] After lamination, the laminated resin sheets may be smoothed by pressing a heat-sealing member from the support side under normal pressure (atmospheric pressure). The pressing conditions for the smoothing process can be the same as the heat-sealing conditions for lamination. Lamination and smoothing may be performed continuously using a vacuum laminator.

[0177] <Process (C)> Step (C) involves curing the resin composition layer laminated on the substrate to form an insulating layer. This creates an insulating layer that embeds the conductive pillars.

[0178] The resin composition layer is usually cured by thermal curing. The thermal curing conditions for the resin composition layer may vary depending on the type of resin composition. For example, the curing temperature is 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 may be preferably 5 minutes to 120 minutes, more preferably 10 minutes to 100 minutes, and even more preferably 15 minutes to 100 minutes.

[0179] The method for manufacturing a package substrate may include preheating the resin composition layer at a temperature lower than the curing temperature before the resin composition layer is heat-cured. For example, prior to heat-curing the resin composition layer, the resin composition layer may be preheated at a temperature of typically 50°C to 150°C, preferably 60°C to 140°C, more preferably 70°C to 130°C for 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. Preheating is usually performed after step (B). Also, if a smoothing treatment is performed after lamination of the substrate and the resin sheet, preheating may usually be performed after the smoothing treatment.

[0180] The process may include a step of peeling off the support of the resin sheet before step (D). The peeling off of the support may be performed between steps (B) and (C), or before step (D) which is after step (C).

[0181] <Process (D)> In step (D), the surface of the insulating layer is polished to expose the conductor pillars embedded in the insulating layer.

[0182] The polishing in process (D) can be carried out by polishing methods such as belt polishing, buffing, ceramic polishing, or surface grinding, and it is preferable to use a surface grinding machine. Depending on the desired surface condition of the insulating layer after polishing and cutting, abrasive grains of various grits can be used.

[0183] <Other processes> When manufacturing a package substrate, after the completion of step (D), a further step (E) of forming a conductive layer may be performed. Step (E) may be carried out according to various methods known to those skilled in the art that are used in the manufacture of printed circuit boards. Furthermore, if necessary, steps (A) to (E) may be repeated to form a multilayer circuit board.

[0184] Step (E) is a step of forming a conductive layer, in which a conductive layer is formed on an insulating layer. The conductive material used for the conductive layer is not particularly limited. In a preferred embodiment, the conductive 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 conductive layer may be a single-metal layer or an alloy layer, and examples of alloy layers include layers formed from alloys of two or more metals selected from the above group (e.g., nickel-chromium alloy, copper-nickel alloy, and copper-titanium alloy). In particular, from the viewpoint of versatility in conductor layer formation, cost, and ease of patterning, single metal layers of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or alloy layers of nickel-chromium alloy, copper-nickel alloy, or copper-titanium alloy are preferred, single metal layers of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or alloy layers of nickel-chromium alloy are more preferred, and single metal layers of copper are even more preferred.

[0185] The conductive layer may be a single-layer structure, or it may be a multi-layer structure in which two or more single-metal layers or alloy layers made of different types of metals or alloys are laminated. When the conductive layer is a multi-layer structure, the layer in contact with the insulating layer is preferably a single-metal layer of chromium, zinc, or titanium, or an alloy layer of nickel-chromium alloy.

[0186] The thickness of the conductor layer depends on the desired printed circuit board design, but is generally 3 μm to 35 μm, preferably 5 μm to 30 μm.

[0187] In one embodiment, the conductor layer may be formed by plating. For example, a conductor layer having a desired wiring pattern can be formed by plating the surface of the insulating layer using conventionally known techniques such as the semi-additive method or the fully additive method. From the viewpoint of ease of manufacture, it is preferable to form it by the semi-additive method. An example of forming the conductor layer by the semi-additive method is shown below.

[0188] First, a plating seed layer is formed on the surface of the insulating layer by electroless plating. Next, a mask pattern is formed on the formed plating seed layer, exposing a portion of the plating seed layer corresponding to the desired wiring pattern. After forming a metal layer on the exposed plating seed layer by electroplating, the mask pattern is removed. Subsequently, the unnecessary plating seed layer can be removed by etching or other means to form a conductor layer having the desired wiring pattern.

[0189] The package substrate manufactured by the package substrate manufacturing method of the present invention may be either a fan-in type package or a fan-out type package. When the package substrate is a fan-out type package, the inherent advantage of the fan-out type package, which is that a redistribution layer can be formed over a large area, allows for the formation of a conductor circuit over a large area with fine patterns.

[0190] The resin sheet used in this invention exhibits excellent embedding properties because the thickness variation of the resin composition layer is small, allowing the resin composition layer to be embedded seamlessly into the conductive pillar. Specifically, the resin composition layers of the resin sheet are laminated to embed the conductive pillar, and the resin composition layers are heat-cured at 130°C for 30 minutes, followed by 170°C for 30 minutes to obtain a cured product. At this time, when the number of voids between the conductive pillar and the cured product is counted using a digital microscope, the number of voids is zero. The embedding properties can be evaluated by the method described in the examples below.

[0191] The resin sheet used in the present invention has small variations in the thickness of the resin composition layer, which suppresses the occurrence of areas where the conductor pillars are exposed and areas where they are not exposed. Therefore, it exhibits the characteristic that already exposed conductor pillars are not polished together with the insulating layer, i.e., drag is suppressed. Drag can be evaluated by the value obtained by dividing the film thickness tolerance of the resin composition layer in the resin sheet by the height of the conductor pillars. The smaller this value, the more the occurrence of areas where the conductor pillars are exposed and areas where they are not exposed is suppressed, and the more drag is suppressed. Furthermore, the smaller this value, the more the occurrence of areas with thin and thick resin composition layers is suppressed, which also indicates that the conductor pillars can be embedded without gaps. The value obtained by dividing the film thickness tolerance by the height of the conductor pillars is preferably 0.21 or less, more preferably 0.20 or less, even more preferably 0.19 or less, 0.18 or less, 0.17 or less, 0.16 or less, or 0.15 or less. The lower limit is preferably 0 or greater, more preferably 0.01 or greater, even more preferably 0.03 or greater, or 0.05 or greater. The value obtained by dividing the film thickness tolerance by the height of the conductor pillar can be determined by the method described in the examples below. [Examples]

[0192] The present invention will be described in detail below with reference to examples. The present invention is not limited to these examples. In the following, unless otherwise specified, "parts" and "%" refer to "parts by mass" and "mass%", respectively. Unless otherwise specified, the temperature and pressure conditions are room temperature (25°C) and atmospheric pressure (1 atm).

[0193] (1) Preparation of support A PET film with an alkyd resin release layer (Lintec Corporation's "AL5", 38 μm thick, hereinafter referred to as "release PET film") was suspended by fixing one edge in the TD direction so that the TD direction of the PET film was aligned with the vertical direction, and then a metal plate was placed as a weight on the other edge in the TD direction so that uniform tension was applied to the entire PET film. At this time, under atmospheric pressure in an air atmosphere, the weight of the metal plate was adjusted to apply the tension shown in the table below, and support 1, support 2, and support 4 were obtained by preheating treatment while applying tension at the heating temperature and heating time shown in the table below. Support 3 was not subjected to preheating treatment of the release PET film.

[0194] [Synthesis of Elastomer A] 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 aromatic hydrocarbon mixed solvent (Idemitsu Petrochemical Co., Ltd., Ipsol 150), and 0.005 g of dibutyltin laurate were added and mixed until homogeneous. Once homogeneous, the temperature was raised to 60°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.

[0195] Next, 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 to the reactant, and the temperature was raised to 150°C while stirring, and the reaction was carried out for approximately 10 hours. FT-IR measurements were taken at 2250 cm⁻¹. -1 The disappearance of the NCO peak was confirmed. The reaction was considered to have terminated upon confirmation of the disappearance of the NCO peak, and the reactants were cooled to room temperature. The reactants were then filtered through a 100-mesh filter cloth to obtain an elastomer having a butadiene structure and phenolic hydroxyl groups (phenolic hydroxyl group-containing butadiene resin: 45% by mass of nonvolatile components). The number-average molecular weight of elastomer A was 5900, and its glass transition temperature was -7°C.

[0196] [Inorganic fillers used] Inorganic filler A: average particle size 3μm, specific surface area 3.5m 2 / g, surface-treated with KBM573 (manufactured by Shin-Etsu Chemical Co., Ltd.). Inorganic filler B: average particle size 0.5μm, specific surface area 5.9m 2 / g, surface-treated with KBM573 (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0197] [Example 1] <Manufacturing of resin sheets> Thirty parts of bixylenol-type epoxy resin (Mitsubishi Chemical Corporation's "YX4000HK," epoxy equivalent approximately 185 g / eq.), twenty parts of biphenyl-type epoxy resin (Nippon Kayaku Co., Ltd.'s "NC3000L," epoxy equivalent approximately 272 g / eq.), and ten parts of naphthylene ether-type epoxy resin (DIC Corporation's "HP-6000L," epoxy equivalent 215 g / eq.) were heated and dissolved with stirring in a mixed solvent of twenty parts of solvent naphtha and thirty parts of cyclohexanone. This mixture was then cooled to room temperature to prepare the epoxy resin solution composition. This epoxy resin dissolution composition contains 30 parts of elastomer A, 20 parts of a phenolic curing agent having a triazine skeleton and novolac structure (DIC Corporation's "LA3018-50P", approximately 151 g / eq. of reactive groups, 50% non-volatile content in a 2-methoxypropanol solution), and an active ester curing agent (DIC Corporation's "HPC-8000-65T", approximately 223 g / eq. of reactive groups, 65% by mass of toluene). 50 parts of solution, 10 parts of carbodiimide-based curing agent (V-03 manufactured by Nisshinbo Chemical Co., Ltd., carbodiimide group equivalent 216 g / eq., toluene solution with 50% non-volatile content), 1 part of curing accelerator (1-benzyl-2-phenylimidazole (1B2PZ), MEK solution with 10% non-volatile content), 10 parts of curing accelerator (4-dimethylaminopyridine (DMAP), MEK solution with 2.5% solid content), and 650 parts of inorganic filler A were mixed and uniformly dispersed in a high-speed rotary mixer to prepare resin varnish 1.

[0198] The resin varnish 1 was uniformly applied to the release layer of the support 1 so that the thickness of the resin composition layer after drying was 150 μm. Then, the resin varnish 1 was dried at 115°C for 3 minutes to produce a resin sheet A including the support and the resin composition layer. Resin sheet B was produced using the same method as for resin sheet A, which had a resin composition layer thickness of 150 μm after drying, except that the resin composition layer thickness after drying was 40 μm.

[0199] The film thickness and film thickness tolerance of the resin composition layer of the fabricated resin sheet A were measured using a contact-type film thickness gauge (Mitutoyo Corporation, "MCD-25MJ"). The film thickness (average value of 27 measurements taken in the TD direction) was 150 μm (average film thickness of 150 μm, film thickness tolerance of 16 μm).

[0200] <Measurement of elongation rate of support 1> The support 1 was peeled off from the resin sheet A prepared in Example 1, and a test specimen was cut out so that the TD direction was aligned with the longer side. The tensile strength of this test specimen was measured using the RTC-1250A tensile testing machine manufactured by Orientec Co., Ltd., and the elongation in the TD direction was measured at 23°C, 115°C, and 140°C. The measurements were performed in accordance with JIS K7127:1999. Each measurement was performed five times, and the average of the top three scores was calculated. The results are shown in the table below.

[0201] [Example 2] In Example 1, support 1 was replaced with support 2. Resin sheets A and B were prepared in the same manner as in Example 1, except for the above. The film thickness of the resin composition layer in resin sheet A was measured in the same manner as in Example 1, and the film thickness was 150 μm (average film thickness was 150 μm, and film thickness tolerance was 13 μm).

[0202] <Measurement of elongation of support 2> The resin sheet A prepared in Example 1 was replaced with the resin sheet A prepared in Example 2. Except for the above, the elongation rate of support 2 was measured in the same manner as the measurement of the elongation rate of support 1.

[0203] [Example 3] In Example 1, resin varnish 1 was replaced with resin varnish 2, which was prepared as follows. Except for the above, resin sheets A and B were prepared in the same manner as in Example 1. The film thickness of the resin composition layer in resin sheet A was measured in the same manner as in Example 1, and the film thickness was 150 μm (average film thickness was 150 μm, and film thickness tolerance was 15 μm).

[0204] 2 parts of bisphenol A type epoxy resin (Nippon Steel & Sumitomo Metal Chemical Co., Ltd. "YD-8125G", epoxy equivalent approximately 174 g / eq.), 5 parts of bixylenol type epoxy resin (Mitsubishi Chemical Corporation "YX4000HK", epoxy equivalent approximately 185 g / eq.), 5 parts of naphthylene ether type epoxy resin (DIC Corporation "EXA-7311-G4", epoxy equivalent approximately 213 g / eq.), biphenyl type epoxy resin (Nippon Kayaku Co., Ltd. "NC30 15 parts of 00L (epoxy equivalent of approximately 272 g / eq.), 2 parts of epoxidized polybutadiene (Daicel Corporation's "PB3600", epoxy equivalent of approximately 193 g / eq.), and 10 parts of phenoxy resin (Mitsubishi Chemical Corporation's "YX7553BH30", a 1:1 solution of cyclohexanone and methyl ethyl ketone (MEK) with a solid content of 30% by mass) were heated and dissolved in a mixed solvent of 15 parts solvent naphtha and 10 parts cyclohexanone while stirring. After cooling to room temperature, add 5 parts of a triazine skeleton-containing cresol novolac curing agent (DIC Corporation's "LA3018-50P", hydroxyl group equivalent approximately 151 g / eq., 2-methoxypropanol solution with 50% solids), 12 parts of an active ester curing agent (DIC Corporation's "HPC-8000-65T", active group equivalent approximately 223 g / eq., toluene solution with 65% by mass of nonvolatile components), and a carbodiimide resin (Nisshinbo Chemical Corporation's " Resin varnish 2 was prepared by mixing 10 parts of "V-03" (a toluene solution containing 216 g / eq. of carbodiimide equivalents and 50% by mass of nonvolatile components), 3 parts of a curing accelerator (a MEK solution containing 4-dimethylaminopyridine (DMAP) and 2.5% by mass of solids), 2 parts of a flame retardant ("HCA-HQ" manufactured by Sanko Co., Ltd., 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphophenanthrene-10-oxide, with an average particle size of 1.2 μm), and 180 parts of inorganic filler B, and uniformly dispersing them in a high-speed rotary mixer.

[0205] [Example 4] In Example 3, support 1 was replaced with support 2. Resin sheets A and B were prepared in the same manner as in Example 3, except for the above. The film thickness of the resin composition layer in resin sheet A was measured in the same manner as in Example 1, and the film thickness was 150 μm (average film thickness was 150 μm, and film thickness tolerance was 15 μm).

[0206] [Example 5] In Example 1, resin varnish 1 was replaced with resin varnish 3, which was prepared as follows. Except for the above, resin sheets A and B were prepared in the same manner as in Example 1. The film thickness of the resin composition layer in resin sheet A was measured in the same manner as in Example 1, and the film thickness was 150 μm (average film thickness was 150 μm, and film thickness tolerance was 14 μm).

[0207] Thirty parts of bixylenol-type epoxy resin (Mitsubishi Chemical Corporation's "YX4000HK," epoxy equivalent approximately 185 g / eq.), twenty parts of biphenyl-type epoxy resin (Nippon Kayaku Co., Ltd.'s "NC3000L," epoxy equivalent approximately 272 g / eq.), and ten parts of naphthylene ether-type epoxy resin (DIC Corporation's "HP-6000L," epoxy equivalent 215 g / eq.) were heated and dissolved with stirring in a mixed solvent of twenty parts of solvent naphtha and thirty parts of cyclohexanone. This mixture was then cooled to room temperature to prepare the epoxy resin solution. To this epoxy resin dissolution composition, 30 parts of elastomer A, 20 parts of a phenolic curing agent having a triazine skeleton and novolac structure (DIC Corporation's "LA3018-50P", reactive group equivalent approximately 151 g / eq., 2-methoxypropanol solution with 50% non-volatile content), 10 parts of a carbodiimide curing agent (Nisshinbo Chemical Corporation's "V-03", carbodiimide group equivalent 216 g / eq., toluene solution with 50% non-volatile content), 1 part of a curing accelerator (1-benzyl-2-phenylimidazole (1B2PZ), MEK solution with 10% non-volatile content), 10 parts of another curing accelerator (4-dimethylaminopyridine (DMAP), MEK solution with 2.5% solid content), and 610 parts of inorganic filler A were mixed and uniformly dispersed in a high-speed rotary mixer to prepare resin varnish 3.

[0208] [Example 6] In Example 1, resin varnish 1 was replaced with resin varnish 4 prepared as follows. Except for the above, resin sheets A and B were prepared in the same manner as in Example 1. The film thickness of the resin composition layer in resin sheet A was measured in the same manner as in Example 1, and the film thickness was 150 μm (average film thickness was 150 μm, and film thickness tolerance was 12 μm).

[0209] Ten parts of bisphenol-type epoxy resin (Nippon Steel & Sumitomo Metal Chemicals Co., Ltd. "ZX1059", a 1:1 mixture of bisphenol A and bisphenol F, epoxy equivalent 169 g / eq.) and fifty parts of naphthol-type epoxy resin (Nippon Steel & Sumitomo Metal Chemicals Co., Ltd. "ESN475V", epoxy equivalent approximately 330 g / eq.) were heated and dissolved in 40 parts of solvent naphtha with stirring. This mixture was then cooled to room temperature to prepare the epoxy resin solution composition. This epoxy resin dissolution composition contains 5 parts of phenoxy resin (Mitsubishi Chemical Corporation's "YX7553BH30", a 1:1 solution of MEK and cyclohexanone with a non-volatile content of 30% by mass), 5 parts of a phenolic curing agent having a triazine skeleton and novolac structure (DIC Corporation's "LA3018-50P", a 2-methoxypropanol solution with a reaction group equivalent of approximately 151 g / eq. and a non-volatile content of 50%), and an active ester curing agent (DIC Corporation's "HPC-8000-65T", a toluene solution with a reaction group equivalent of approximately 223 g / eq. and a non-volatile content of 65% by mass). 70 parts of (meth)acrylic acid solution, 20 parts of (meth)acrylic acid ester (A-DOG, manufactured by Shin Nakamura Chemical Co., Ltd., equivalent to 156 g / eq. of (meth)acryloyl groups), 15 parts of carbodiimide-based curing agent (V-03, manufactured by Nisshinbo Chemical Co., Ltd., equivalent to 216 g / eq. of carbodiimide groups, toluene solution with 50% by mass of non-volatile content), 6 parts of curing accelerator (1-benzyl-2-phenylimidazole (1B2PZ), MEK solution with 10% by mass of non-volatile content), 2 parts of polymerization initiator (Perkmill D (manufactured by NOF Corporation, MEK solution with 20% non-volatile content)), 470 parts of inorganic filler B, 10 parts of cyclohexanone, and 10 parts of MEK were mixed and uniformly dispersed in a high-speed rotary mixer to prepare resin varnish 4.

[0210] [Example 7] In Example 6, support 1 was replaced with support 2. Resin sheets A and B were prepared in the same manner as in Example 6, except for the above. The film thickness of the resin composition layer in resin sheet A was measured in the same manner as in Example 1, and the film thickness was 150 μm (average film thickness was 150 μm, and film thickness tolerance was 11 μm).

[0211] [Example 8] Thirty parts of bixylenol-type epoxy resin (Mitsubishi Chemical Corporation's "YX4000HK," epoxy equivalent approximately 185 g / eq.), twenty parts of biphenyl-type epoxy resin (Nippon Kayaku Co., Ltd.'s "NC3000L," epoxy equivalent approximately 272 g / eq.), and ten parts of naphthylene ether-type epoxy resin (DIC Corporation's "HP-6000L," epoxy equivalent 215 g / eq.) were heated and dissolved with stirring in a mixed solvent of twenty parts of solvent naphtha and thirty parts of cyclohexanone. This mixture was then cooled to room temperature to prepare the epoxy resin solution composition. This epoxy resin dissolution composition contains 30 parts of elastomer A, 20 parts of a phenolic curing agent having a triazine skeleton and novolac structure (DIC Corporation's "LA3018-50P", approximately 151 g / eq. of reactive groups, 50% non-volatile content in a 2-methoxypropanol solution), and an active ester curing agent (DIC Corporation's "HPC-8000-65T", approximately 223 g / eq. of reactive groups, 65% by mass of toluene). 50 parts of solution, 10 parts of carbodiimide-based curing agent (V-03 manufactured by Nisshinbo Chemical Co., Ltd., carbodiimide group equivalent 216 g / eq., toluene solution with 50% by mass of nonvolatile content), 1 part of curing accelerator (1-benzyl-2-phenylimidazole (1B2PZ), MEK solution with 10% by mass of nonvolatile content), 10 parts of curing accelerator (4-dimethylaminopyridine (DMAP), MEK solution with 2.5% by mass of solid content), and 650 parts of inorganic filler A were mixed and uniformly dispersed in a high-speed rotary mixer to prepare resin varnish 5.

[0212] The resin varnish 5 was uniformly applied to the release layer of the support 1 so that the thickness of the resin composition layer after drying was 200 μm. Then, the resin varnish 5 was dried at 115°C for 4.5 minutes to produce a resin sheet A including the support and the resin composition layer. Resin sheet B was also produced using the same method as for resin sheet A, which had a resin composition layer thickness of 200 μm after drying, except that the resin composition layer thickness after drying was 40 μm. The film thickness of the resin composition layer in resin sheet A was measured in the same manner as in Example 1, and the film thickness was 200 μm (average film thickness was 200 μm, and film thickness tolerance was 33 μm).

[0213] [Example 9] Thirty parts of bixylenol-type epoxy resin (Mitsubishi Chemical Corporation's "YX4000HK," epoxy equivalent approximately 185 g / eq.), twenty parts of biphenyl-type epoxy resin (Nippon Kayaku Co., Ltd.'s "NC3000L," epoxy equivalent approximately 272 g / eq.), and ten parts of naphthylene ether-type epoxy resin (DIC Corporation's "HP-6000L," epoxy equivalent 215 g / eq.) were heated and dissolved with stirring in a mixed solvent of twenty parts of solvent naphtha and thirty parts of cyclohexanone. This mixture was then cooled to room temperature to prepare the epoxy resin solution composition. This epoxy resin dissolution composition contains 30 parts of elastomer A, 20 parts of a phenolic curing agent having a triazine skeleton and novolac structure (DIC Corporation's "LA3018-50P", approximately 151 g / eq. of reactive groups, 50% non-volatile content in a 2-methoxypropanol solution), and an active ester curing agent (DIC Corporation's "HPC-8000-65T", approximately 223 g / eq. of reactive groups, 65% by mass of toluene). 50 parts of solution, 10 parts of carbodiimide-based curing agent (V-03 manufactured by Nisshinbo Chemical Co., Ltd., carbodiimide group equivalent 216 g / eq., toluene solution with 50% non-volatile content), 1 part of curing accelerator (1-benzyl-2-phenylimidazole (1B2PZ), MEK solution with 10% non-volatile content), 10 parts of curing accelerator (4-dimethylaminopyridine (DMAP), MEK solution with 2.5% solid content), and 650 parts of inorganic filler A were mixed and uniformly dispersed in a high-speed rotary mixer to prepare resin varnish 6.

[0214] The resin varnish 6 was uniformly applied to the release layer of the support 1 so that the thickness of the resin composition layer after drying was 300 μm. Then, the resin varnish 6 was dried at 115°C for 6.5 minutes to produce a resin sheet A including the support and the resin composition layer. Resin sheet B was also produced using the same method as for resin sheet A, which had a resin composition layer thickness of 300 μm after drying, except that the thickness of the resin composition layer after drying was 40 μm. The film thickness of the resin composition layer in resin sheet A was measured in the same manner as in Example 1, and the film thickness was 300 μm (average film thickness was 300 μm, and film thickness tolerance was 48 μm).

[0215] [Example 10] In Example 9, support 1 was replaced with support 4. Resin sheets A and B were prepared in the same manner as in Example 9, except for the above. The film thickness of the resin composition layer in resin sheet A was measured in the same manner as in Example 1, and the film thickness was 150 μm (average film thickness was 150 μm, and film thickness tolerance was 12 μm).

[0216] <Measurement of elongation of support material 4> The resin sheet A prepared in Example 1 was replaced with the resin sheet A prepared in Example 10. Aside from the above, the elongation rate of support 4 was measured in the same manner as the measurement of the elongation rate of support 1.

[0217] [Comparative Example 1] In Example 1, support 1 was replaced with support 3. Resin sheets A and B were prepared in the same manner as in Example 1, except for the above. The film thickness of the resin composition layer in resin sheet A was measured in the same manner as in Example 1, and the film thickness was 150 μm (average film thickness was 150 μm, and film thickness tolerance was 28 μm).

[0218] <Measurement of elongation of support 3> The resin sheet A prepared in Example 1 was replaced with the resin sheet A prepared in Comparative Example 1. Except for the above, the elongation rate of support 3 was measured in the same manner as the measurement of the elongation rate of support 1.

[0219] [Comparative Example 2] In Example 3, support 1 was replaced with support 3. Resin sheets A and B were prepared in the same manner as in Example 3, except for the above. The film thickness of the resin composition layer in resin sheet A was measured in the same manner as in Example 1, and the film thickness was 150 μm (average film thickness was 150 μm, and film thickness tolerance was 32 μm).

[0220] [Comparative Example 3] In Example 6, support 1 was replaced with support 3. Resin sheets A and B were prepared in the same manner as in Example 6, except for the above. The film thickness of the resin composition layer in resin sheet A was measured in the same manner as in Example 1, and the film thickness was 150 μm (average film thickness was 150 μm, and film thickness tolerance was 29 μm).

[0221] [Comparative Example 4] In Example 8, support 1 was replaced with support 3. Resin sheets A and B were prepared in the same manner as in Example 8, except for the above. The film thickness of the resin composition layer in resin sheet A was measured in the same manner as in Example 1, and the film thickness was 200 μm (average film thickness was 200 μm, and film thickness tolerance was 67 μm).

[0222] [Comparative Example 5] In Example 9, support 1 was replaced with support 3. Except for the above, resin sheets A and B were prepared in the same manner as in Example 8. The film thickness of the resin composition layer in resin sheet A was measured in the same manner as in Example 1, and the film thickness was 300 μm (average film thickness of 300 μm, film thickness tolerance of 109 μm).

[0223] [evaluation] <Evaluation of variations in the thickness of the resin composition layer> The thickness tolerance of the resin composition layer in resin sheet A, where the thickness of the resin composition layer is 150 μm (200 μm in Example 8 and Comparative Example 4, and 300 μm in Example 9 and Comparative Example 5), was calculated by dividing it by the thickness of the resin composition layer.

[0224] <Evaluation of embedding ability and drag resistance> (1) Preparation of evaluation boards 1-3 An evaluation substrate 1 was prepared by arranging Cu pillars (diameter 100 μm, height 130 μm) on an FR-4 substrate (500 mm × 500 mm × 0.8 mm (thickness)) with a distance of 180 μm between pillars.

[0225] An evaluation substrate 2 was prepared by arranging Cu pillars (diameter 100 μm, height 170 μm) on an FR-4 substrate (500 mm × 500 mm × 0.8 mm (thickness)) with a distance of 180 μm between pillars.

[0226] An evaluation substrate 3 was prepared by arranging Cu pillars (100 μm in diameter, 250 μm in height) on an FR-4 substrate (500 mm × 500 mm × 0.8 mm (thickness)) with a distance of 180 μm between pillars.

[0227] (2) Lamination of resin sheets In Examples 1-7, Example 10, and Comparative Examples 1-3, a batch-type vacuum pressure laminator (Nikko Materials Co., Ltd. 2-stage build-up laminator "CVP700") was used to arrange resin sheet A so that a 150 μm thick resin composition layer covered the Cu pillars of evaluation substrate 1, and then laminated it. This lamination was performed by reducing the pressure to 13 hPa or less by depressurizing for 30 seconds, and then pressing at a molding temperature of 100-140°C and a pressure of 0.74 MPa for 30 seconds.

[0228] In Example 8 and Comparative Example 4, a batch-type vacuum pressure laminator (Nikko Materials Co., Ltd. 2-stage build-up laminator "CVP700") was used to arrange resin sheet A so that a 200 μm thick resin composition layer covered the Cu pillars of the evaluation substrate 2, and then laminated it. This lamination was performed by reducing the pressure to 13 hPa or less for 30 seconds, and then pressing it at a molding temperature of 100-140°C and a pressure of 0.74 MPa for 30 seconds.

[0229] In Example 9 and Comparative Example 5, a batch-type vacuum pressure laminator (Nikko Materials Co., Ltd. 2-stage build-up laminator "CVP700") was used to arrange resin sheet A so that a 300 μm thick resin composition layer covered the Cu pillars of the evaluation substrate 3, and then laminated it. This lamination was performed by reducing the pressure to 13 hPa or less for 30 seconds, and then pressing it at a molding temperature of 100-140°C and a pressure of 0.74 MPa for 30 seconds.

[0230] (3) Curing of the resin composition layer Evaluation substrates 1 to 3, each laminated with a resin composition layer, were placed in a 130°C oven at a temperature of 130°C and subjected to a pre-curing process for 30 minutes. Subsequently, they were transferred to a 200°C oven at a temperature of 200°C and subjected to a post-curing process for 90 minutes to heat-cur the resin composition layer and obtain evaluation substrate B.

[0231] (4) Evaluation of embedding ability and drag. The number of Cu pillar embedding defects in evaluation substrates 1-3 was counted using a digital microscope (Keyence VHX-7000). The occurrence of voids in evaluation substrates 1-3 was evaluated according to the following criteria. ○: Number of voids is 0 ×: The number of voids is 1 or more.

[0232] The thickness tolerance of the resin composition layer in resin sheet A, where the thickness of the resin composition layer is 150 μm (200 μm in Example 8 and Comparative Example 4, and 300 μm in Example 9 and Comparative Example 5), was calculated by dividing it by the height of the Cu pillars on evaluation substrates 1 to 3.

[0233] <Measurement of Dielectric Loss Tangent of Hardened Materials> A release PET film (Lintec Corporation "501010", 38 μm thick, 240 mm square) was placed on a glass cloth-based epoxy resin double-sided copper-clad laminate (Matsushita Electric Works "R5715ES", 0.7 mm thick, 255 mm square) so that its untreated surface was in contact with the laminate, and the four sides of the release PET film were fixed with polyimide adhesive tape (10 mm wide).

[0234] A resin sheet B (200 mm square) with a resin composition layer thickness of 40 μm was laminated in the center using a batch-type vacuum pressure laminator (Nikko Materials Co., Ltd., 2-stage build-up laminator, CVP700) so that the resin composition layer was in contact with the release surface of a release PET film (Lintec Corporation, "501010"). The lamination process was carried out by reducing the pressure to 13 hPa or less for 30 seconds, followed by pressing at 100°C and a pressure of 0.74 MPa for 30 seconds.

[0235] Next, after peeling the release PET (support) from the resin sheet B, the material was placed in a 130°C oven for 30 minutes, then transferred to a 200°C oven for 90 minutes to heat-cur it, and a cured product for evaluation was obtained.

[0236] The above-mentioned cured material for evaluation was cut into test specimens measuring 1.5 mm in width and 80 mm in length. The dielectric loss tangent (Df) of each test specimen was measured using the cavity resonance perturbation method with an Agilent Technologies HP8362B at a measurement frequency of 5.8 GHz and a measurement temperature of 23 °C. Measurements were performed on three test specimens, and the average value was calculated.

[0237] <Measurement of hardening shrinkage rate> A resin sheet B (100 mm square) with a resin composition layer thickness of 40 μm was laminated to a polyimide film (UPILEX50S, Ube Industries, Ltd.) using a batch-type vacuum pressure laminator (Nikko Materials Co., Ltd., 2-stage build-up laminator, CVP700) so that the resin composition layer was in contact with the polyimide film to obtain a sheet. Two 7 mm diameter holes were formed in the obtained sheet, and the distance between the two points (L1) was measured using an image measuring instrument (Mitutoyo Quick Vision QVH1X606-PROIII BHU2G). Subsequently, the resin composition layer was cured at 200°C for 90 minutes, and the resulting cured product was peeled off the polyimide film, and the distance between the two points (L2) was measured again. The value was calculated using the formula (L1-L2) / L1×100. This was repeated five times, and the average value was taken as the curing shrinkage rate.

[0238] [Table 1]

[0239] [Table 2]

Claims

1. (A) A step of preparing a resin sheet comprising a support and a resin composition layer provided on the support containing a resin composition, (B) A step of laminating a resin composition layer of a resin sheet onto a substrate on which conductive pillars are provided on the surface, so as to embed the conductive pillars. (C) A step of curing the resin composition layer to form an insulating layer, and (D) A method for manufacturing a package substrate, comprising the step of polishing the surface of the insulating layer to expose the conductor pillars, A method for manufacturing a package substrate, wherein when A is the elongation rate of the support in the TD direction or MD direction at 115°C, and B is the elongation rate of the support in the same direction as the elongation rate at 115°C at 23°C, A / B is less than 1.

30.

2. A method for manufacturing a package substrate according to claim 1, wherein the thickness of the resin composition layer exceeds 100 μm.

3. A method for manufacturing a package substrate according to claim 1, wherein step (B) is performed by a vacuum lamination method.

4. A method for manufacturing a package substrate according to claim 1, wherein the height of the conductor pillar is 70 μm or more.

5. A method for manufacturing a package substrate according to claim 1, wherein the resin composition layer includes an inorganic filler.

6. The method for manufacturing a package substrate according to claim 5, wherein the content of the inorganic filler is 70% by mass or more, when the non-volatile components in the resin composition are taken as 100% by mass.

7. A method for manufacturing a package substrate according to claim 1, wherein the curing shrinkage rate of a cured product obtained by heat-curing a resin composition layer at 200°C for 90 minutes is 0.20% or less.

8. A method for manufacturing a package substrate according to claim 1, wherein C is the elongation rate of the support in the TD direction or MD direction at 140°C, and B is the elongation rate of the support in the same direction as the elongation rate at 140°C at 23°C, and C / B is 1.55 or less.

9. A method for manufacturing a package substrate according to claim 1, wherein the value obtained by dividing the thickness tolerance of the resin composition layer by the thickness of the resin composition layer is 0.18 or less.

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