Substrate with insulating resin layer, laminate using same, and method for manufacturing laminate

Abstract

This insulating-resin-layer-equipped substrate is provided with a substrate, a first resin layer that is provided on the substrate and that has a thickness reduction level of less than 30% when molded under a pressure condition of 3.0 MPa at 220ºC for 60 minutes, and a second resin layer provided on the first resin layer.

Description

[Technical Field]

[0001] The present invention relates to a substrate with an insulating resin layer, a laminate using the same, and a method for producing the laminate. [Background technology]

[0002] In recent years, semiconductor packages widely used in electronic devices, communication devices, personal computers, etc. have been increasingly becoming more functional and smaller. In addition, with this technological development, there has been a demand for thinner printed wiring boards and semiconductor element mounting substrates in semiconductor packages.

[0003] As a method for manufacturing thin printed wiring boards and semiconductor element mounting boards, for example, a method has been disclosed in which a circuit pattern is formed by pattern plating on a laminate formed by forming a copper layer that can be peeled off in a later process on a rigid, thick support substrate (carrier substrate) such as stainless steel, an insulating layer such as epoxy resin-coated fiberglass is then laminated thereon, and heat and pressure treatment is performed, and finally the support substrate is peeled off and removed to manufacture a thin printed wiring board (see, for example, Patent Document 1).In this way, by laminating a circuit pattern and an insulating material on a rigid, thick support substrate, and finally peeling off and removing the support substrate, thin printed wiring boards and semiconductor element mounting boards can be manufactured even using existing manufacturing equipment.

[0004] Furthermore, resin sheets used in these printed wiring boards are known to have multiple resin composition layers, and one such technique is an insulating resin sheet in which the amount of etching of each layer is controlled in order to improve the performance of the multilayered film (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 59-500341 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-50561 Summary of the Invention [Problem to be solved by the invention]

[0006] The sheet described in Patent Document 2 is intended to solve the problem of via formation by laser processing by adjusting the amount of etching of each layer. However, the sheet requires that the total thickness of each layer must be 12 μm or more. Therefore, there is a need to develop a technology that can satisfy requirements such as insulation and embeddability of a patterned conductor layer (hereinafter sometimes simply referred to as "embedding ability") while enabling further thinning (for example, less than 10 μm).

[0007] In order to solve the above-mentioned problems, an object of the present invention is to provide a substrate with an insulating resin layer that is excellent in insulating properties and embeddability, as well as a laminate using the same and a method for producing the laminate. [Means for solving the problem]

[0008] That is, the present invention is as follows. <1> A substrate with an insulating resin layer, comprising: a substrate; a first resin layer provided on the substrate, the first resin layer having a thickness reduction of less than 30% when molded for 60 minutes under conditions of 220°C and a pressure of 3.0 MPa; and a second resin layer provided on the first resin layer. <2> The second resin layer has a minimum melt viscosity of 100,000 Pa·s or less. <1> The substrate with an insulating resin layer according to claim 1. <3> The thickness of the first resin layer is less than 10 μm. <1> or <2> The substrate with an insulating resin layer according to claim 1. <4> The thickness of the second resin layer is 2.0 μm or more. <1> ~ <3> 10. The substrate with an insulating resin layer according to any one of the preceding items. <5> The total thickness of the first resin layer and the second resin layer is 3 μm or more and 20 μm or less. <1> ~ <4> 10. The substrate with an insulating resin layer according to any one of the preceding items. <6> the first resin layer contains at least one selected from the group consisting of polyimide, liquid crystal polyester, epoxy resin, cyanate ester compound, maleimide compound, phenolic resin, thermosetting modified polyphenylene ether resin, benzoxazine compound, organic group-modified silicone compound, and compound having a polymerizable unsaturated group; <1> ~ <5> 10. The substrate with an insulating resin layer according to any one of the preceding items. <7> the second resin layer contains at least one selected from the group consisting of epoxy resins, cyanate ester compounds, maleimide compounds, phenolic resins, thermosetting modified polyphenylene ether resins, benzoxazine compounds, organic group-modified silicone compounds, and compounds having a polymerizable unsaturated group; <1> ~ <6> 10. The substrate with an insulating resin layer according to any one of the preceding items. <8> Used to produce a coreless substrate provided on a printed wiring board or a semiconductor element mounting substrate, <1> ~ <7> 10. The substrate with an insulating resin layer according to any one of the preceding items. <9> The coreless substrate is a three-layer coreless substrate. <8> The substrate with an insulating resin layer according to claim 1. <10> a conductor layer; <1> ~ <9> 10. A laminate having an insulating layer formed using the substrate with an insulating resin layer according to any one of 1 to 8, and a build-up layer laminated thereon. <11> At least one of the insulating layers has a thickness of 1 μm or more and less than 15 μm. <10> The laminate according to claim 1. <12> the build-up layer has a plurality of the conductor layers and the insulating layers, and the conductor layers are disposed between the insulating layers and on the surface of the outermost layer of the build-up layer; <10> or <11> The laminate according to claim 1. <13> In the build-up layer, the conductor layers and the insulating layers are alternately stacked, and the build-up layer has three or four insulating layers. <10> ~ <12> The laminate according to any one of the preceding items. <14> It is a coreless substrate, <10> ~ <13> The laminate according to any one of the preceding items. <15> On the surface of the conductor layer, <1> ~ <9> 10. A method for producing a laminate, comprising: forming an insulating layer using the substrate with an insulating resin layer according to any one of claims 1 to 9, thereby forming a build-up layer in which the conductor layer and the insulating layer are laminated. <16> At least one of the insulating layers has a thickness of 1 μm or more and less than 15 μm. <15> A method for producing the laminate described in 1. <17> the buildup layer has a plurality of the conductor layers and the insulating layers, and the conductor layers are disposed between the insulating layers and on the surface of the outermost layer of the buildup layer; <15> or <16> A method for producing the laminate described in 1. <18> The insulating layer has three or four layers. <15> ~ <17> 10. A method for producing the laminate according to any one of the preceding claims. <19> The laminate is a coreless substrate. <15> ~ <18> 10. A method for producing the laminate according to any one of the preceding claims. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a substrate with an insulating resin layer that is excellent in insulating properties and embeddability, as well as a laminate using the same and a method for producing the laminate. [Brief explanation of the drawings]

[0010] [Figure 1] 5 is a schematic diagram for explaining the amount of reduction in thickness of the first resin layer in the present embodiment. FIG. [Figure 2] FIG. 2 is a schematic diagram illustrating an example of a multilayer coreless substrate according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a detailed description of an embodiment of the present invention (hereinafter simply referred to as "the present embodiment") will be given with reference to the drawings as necessary, but the present invention is not limited to the following embodiment. Various modifications of the present invention are possible without departing from the gist of the present invention. In this specification, a laminate is one in which each layer is adhered to another, but the layers may be peelable from one another as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant explanations will be omitted. Furthermore, unless otherwise specified, the positional relationships, such as up, down, left, and right, are based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to those shown. In this specification, "(meth)acrylic" means "acrylic" and the corresponding "methacrylic", and "(meth)acrylate" means "acrylate" and the corresponding "methacrylate".

[0012] In this embodiment, unless otherwise specified, "resin solid content" or "resin solid content in an insulating resin layer" refers to the resin contained in an insulating resin layer or a resin composition and the components that constitute the resin after curing. Also, "100 parts by mass of resin solid content" refers to the total of 100 parts by mass of the resin in an insulating resin layer or a resin composition and the components that constitute the resin after curing.

[0013] [Base material with insulating resin layer] The substrate with an insulating resin layer of this embodiment (hereinafter sometimes simply referred to as a "substrate with a resin layer") includes a substrate, a first resin layer (hereinafter sometimes simply referred to as a "first resin layer") disposed on the substrate, and having a thickness loss of less than 30% when molded for 60 minutes under conditions of 220°C and a pressure of 3.0 MPa, and a second resin layer (hereinafter sometimes simply referred to as a "second resin layer") disposed on the first resin layer. Hereinafter, the "thickness loss when molded for 60 minutes under conditions of 220°C and a pressure of 3.0 MPa" will also be simply referred to as the "thickness loss." Similarly, the first and second resin layers will also be collectively referred to as the "resin layers of this embodiment."

[0014] The substrate with a resin layer of this embodiment includes a first resin layer whose thickness has been reduced by less than 30% and a second resin layer. The second resin layer typically contains a resin that exhibits fluidity during press processing, and the layer itself exhibits fluidity during press processing. The second resin layer typically embeds a component that forms a laminate together with the substrate with a resin layer from the side that contacts the surface of the second resin layer (hereinafter, this layer may be referred to as the "embedded layer"). Examples of such components include a conductor layer such as a circuit pattern on a substrate. The conductor layer corresponds to the convex portions of the uneven shape formed together with the substrate, and is embedded in the second resin layer. Furthermore, the first resin layer maintains the distance between the substrate and the second resin layer within a predetermined range even after press processing, such as during laminate formation, in order to maintain insulation between the convex portions embedded in the second resin layer and the substrate. (Hereinafter, this layer may be referred to as the "thickness-maintaining layer"). In other words, the first resin layer separates the substrate and the second resin layer even after press processing. Because the second resin layer functions as a buried layer, it is preferable that the second resin layer differ from the first resin layer in at least one of its constituent components and physical properties. While not particularly limited, examples of the different first and second resin layers include those in which the first and second resin layers have different components, those in which the physical properties of these layers are different, and combinations of these. Examples of the different components of the first and second resin layers include those in which the resin types are different, such as using a polyimide for the first resin layer and an epoxy resin for the second resin layer. Examples of the different physical properties include those in which the compounding ratio of the components contained in each layer or the curing state are adjusted to change physical properties such as the amount of thickness reduction or the minimum melt viscosity. The curing state of the first and second resin layers can be adjusted, for example, by changing the coating conditions for each layer, completely curing the first resin layer and semi-curing the second resin layer.

[0015] The resin layer-attached substrate of this embodiment is useful, for example, as a material for forming an insulating layer on a conductor layer such as a circuit pattern. Examples of such materials include materials for forming insulating layers on printed wiring boards or semiconductor element-mounting substrates used in the manufacture of electronic devices, communication devices, and personal computers. For example, when producing a printed wiring board or the like, the resin layer-attached substrate of this embodiment is placed on a substrate on which a conductor layer such as a circuit pattern is formed, with the second resin layer and the conductor layer in contact with each other. The first and second resin layers are then heated and pressed to harden, forming an insulating layer on the conductor layer. During this process, the conductor layer such as the circuit pattern is embedded in the second resin layer. Meanwhile, the thickness of the insulating layer present on the conductor layer is maintained within a predetermined range by the first resin layer. Thus, with the resin layer-attached substrate of this embodiment, the first resin layer can function as a thickness-maintaining layer, and the second resin layer can function as an embedding layer. In particular, since the resin layer-attached substrate of this embodiment has a thickness reduction of less than 30%, the thickness of the insulating layer itself can be maintained within a desired range even after pressing. Furthermore, the second resin layer has improved resin fluidity during press processing, allowing a conductor layer such as a circuit pattern to be embedded while suppressing gaps. As a result, the base material with a resin layer according to this embodiment can maintain the thickness of the insulating layer within a desired range, thereby providing excellent insulation in the thickness direction of the insulating layer, and allowing a conductor layer to be embedded in the insulating layer while suppressing gaps.

[0016] [Base material] Examples of the substrate include resin films such as polyethylene terephthalate (PET) film, polyimide film, polyamide film, polyester film, polybutylene terephthalate (PBT) film, polypropylene (PP) film, and polyethylene (PE) film, as well as metal foils such as copper foil, aluminum foil, and gold foil. The substrate in this embodiment may be, for example, a substrate with a release layer, such as a resin film with a release layer or a copper foil with a release layer. The substrate may be peeled from the first resin layer as needed during laminate formation, and when a metal foil such as copper foil is used, it may be patterned and used as a conductor layer. The release layer may also be, for example, a release layer that is provided on a typical substrate with a release layer.

[0017] The substrate in this embodiment is not particularly limited, but is preferably a metal foil, more preferably a copper foil. The copper foil may be a copper foil or copper film used in ordinary printed wiring boards. Specific examples of copper foil include electrolytic copper foil, rolled copper foil, and copper alloy film. The copper foil or copper film may be subjected to a known surface treatment, such as a matte treatment, a corona treatment, a nickel treatment, or a cobalt treatment. As the copper foil in this embodiment, commercially available products can be used, such as "GHY5" (trade name, 12 μm thick copper foil) manufactured by JX Nippon Mining & Metals Corporation, "3EC-VLP" (trade name, 12 μm thick copper foil), "3EC-III" (trade name, 12 μm thick copper foil) and "3EC-M2S-VLP" (trade name, 12 μm thick copper foil) manufactured by Mitsui Mining & Smelting Co., Ltd., "GTS-MP" (trade name, 12 μm thick copper foil) manufactured by Furukawa Electric Co., Ltd., and "JXUT-I" (trade name, 1.5 μm thick copper foil) manufactured by JX Nippon Mining & Metals Corporation.

[0018] The arithmetic mean roughness (Ra) of the copper foil surface is preferably 0.05 μm to 2 μm, more preferably 0.08 μm to 1.7 μm, in order to improve the adhesive strength between the copper foil and the resin layer of this embodiment and prevent layer peeling during long-term use. The arithmetic mean roughness (Ra) is particularly preferably 0.2 μm to 1.6 μm, in order to obtain better adhesiveness between the copper foil and the resin layer of this embodiment. In this embodiment, a substrate with an insulating resin layer comprising a copper foil having an arithmetic mean roughness within the above range can be suitably used in the manufacture of printed wiring boards and semiconductor element mounting substrates with high-density fine wiring. The arithmetic mean roughness can be measured using a commercially available shape measuring microscope (e.g., a laser microscope, such as the VK-X210 (product name) manufactured by Keyence Corporation).

[0019] The thickness of the substrate in this embodiment is not particularly limited as long as the effects of this embodiment are achieved. For example, from the viewpoint of improving handleability and reducing costs, it is preferably 5 μm to 200 μm, more preferably 10 μm to 150 μm, and even more preferably 15 μm to 80 μm. Furthermore, when a metal foil such as copper foil is provided as the substrate, its thickness is preferably 1 μm to 18 μm, taking into account the roughening treatment of the surface of the metal foil. Furthermore, from the viewpoint of suitably obtaining thin printed wiring boards and semiconductor element mounting substrates, it is more preferable that the thickness of the substrate is 2 μm to 15 μm.

[0020] [First resin layer] In this embodiment, the first resin layer has a thickness reduction of less than 30% when molded for 60 minutes under conditions of 220° C. and a pressure of 3.0 MPa.

[0021] First, the thickness reduction amount of the first resin layer in this embodiment will be described using FIG. 1. FIG. 1 is a schematic diagram for explaining the thickness reduction amount of the first resin layer in this embodiment. As shown in FIG. 1A, a substrate 10 with a resin layer includes a substrate 12, a first resin layer 14A, and a second resin layer 16A laminated in this order. Similarly, as shown in FIG. 1A, an inner circuit board 20 includes a substrate 22 and a plurality of conductor layers 24 disposed on the substrate 22, and the conductor layers 24 form a circuit having a pattern shape. Furthermore, in the substrate 10 with a resin layer, the second resin layer 16A is disposed so as to contact the surface of the inner circuit board 20 on which the conductor layers 24 are disposed, and then the substrate 10 is heated and pressed (pressed). After the pressing, a laminate 30 is formed as shown in FIG. 1B. The laminate 30 includes an insulating layer 32 formed of a first resin layer 14B and a second resin layer 16B that are formed by curing the first resin layer 14A and the second resin layer 16A, respectively.

[0022] Here, the "thickness reduction amount when molding for 60 minutes under conditions of 220°C and a pressure of 3.0 MPa" for the first resin layer is a numerical value representing the reduction in the thickness of the first resin layer after molding, expressed as a percentage, relative to the thickness of the first resin layer before molding. This thickness reduction amount is calculated from the thickness X of the first resin layer 14A before press processing and the thickness Y of the first resin layer 14B after molding (press processing) for 60 minutes under conditions of 220°C and a pressure of 3.0 MPa. For example, first, the thickness of the first resin layer (thickness X in FIG. 1) is measured from the cross section of the resin layer-attached substrate 10 using a scanning electron microscope (SEM). Next, the laminate 30 is polished to expose a cross section parallel to the lamination to form a sample, and the thickness of the first resin layer (thickness Y in FIG. 1) is measured for the obtained sample using a scanning electron microscope (SEM). After the measurement, the thickness reduction amount can be evaluated by comparing the thickness X of the first resin layer 14A before pressing with the thickness Y of the first resin layer 14B of the laminate 30 after pressing. Specifically, the thickness reduction amount (TΔ) of the first resin layer can be calculated using the following formula (1) from the thickness X of the first resin layer in a base material with a resin layer, for example, in the form of a resin sheet, and the thickness Y of the first resin layer in a laminate, for example, in the form of a copper-clad laminate. Thickness reduction amount (%)=(XY) / X×100 (1) However, a resin layer made of the same material as the first resin layer 14A may be sandwiched between flat sheets that do not deform under the pressure conditions described below, and then molded (pressed) for 60 minutes under the pressure conditions described above. The thickness reduction amount may then be calculated in the same manner from the thickness of the resin layer before and after the molding (press processing) and the result may be used as the thickness reduction amount of the first resin layer.

[0023] The thickness reduction of the first resin layer is less than 30% from the viewpoint of ensuring insulation. If the thickness reduction of the first resin layer is 30% or more, the thickness of the first resin layer will be reduced too much under press processing conditions, such as molding for 60 minutes under conditions of 220°C and a pressure of 3.0 MPa, and the insulation properties of the insulating layer will be reduced. From the viewpoint of ensuring insulation, the thickness reduction of the first resin layer is preferably less than 28%, preferably 25% or less, preferably less than 20%, more preferably less than 10%, and particularly preferably 0%. Note that the lower limit of this thickness reduction is not particularly limited and may be 0%. The thickness reduction of the first resin layer can be adjusted to a desired value by appropriately selecting the type of thermosetting resin contained therein, controlling the degree of curing of the resin, or adding an inorganic filler.

[0024] The thickness of the first resin layer is not particularly limited, but is preferably less than 10 μm from the viewpoint of further thinning. Considering the need to ensure insulation, the thickness of the first resin layer is more preferably greater than 0.7 μm and less than 9.0 μm, even more preferably 1.0 μm or more and less than 9.0 μm, even more preferably 2.0 μm or more and less than 9.0 μm, even more preferably 2.5 μm or more and less than 9.0 μm, and particularly preferably 3.0 μm or more and less than 9.0 μm. The upper limit of the thickness of the first resin layer may be 7.0 μm, 5.0 μm, or 3.0 μm. The first resin layer may be in a semi-cured state (B-Stage) or a fully cured state (C-Stage).

[0025] The minimum melt viscosity of the first resin layer is not particularly limited because its contribution to solving the problems of the present invention is small. However, from the viewpoint of improving thickness reduction and insulating properties, the minimum melt viscosity is preferably 10,000 Pa·s or more, more preferably 100,000 Pa·s to 50,000,000 Pa·s, and particularly preferably 300,000 Pa·s to 50,000,000 Pa·s. In this specification, "minimum melt viscosity" refers to the lowest viscosity measured using a rheometer (viscoelasticity measuring device) under the following conditions: starting temperature 80°C, ending temperature 180°C, heating rate 3°C / min, frequency 10 pts / s, and strain 0.1%. The minimum melt viscosity of the first resin layer can be adjusted to a desired value by appropriately selecting the type of thermosetting resin contained therein, controlling the degree of curing of the resin, or adding an inorganic filler.

[0026] From the viewpoint of further improving the manufacturability of the substrate with an insulating resin layer, the elongation percentage of the first resin layer is preferably 1% or more and less than 50%, more preferably 1% or more and 40% or less, and even more preferably 2% or more and 30% or less. In this specification, the "elongation percentage" is calculated by a measurement method in accordance with JIS K7113-1.

[0027] The first resin layer in this embodiment can be formed by known means such as coating using a varnish, which is preferably a solution of a resin composition containing a thermosetting resin. The thermosetting resin is not particularly limited as long as it satisfies the condition that the thickness reduction is less than 30%, and any desired thermosetting resin can be used depending on the desired physical properties. Furthermore, the resin composition may contain inorganic fillers and other additives, as described below, as necessary.

[0028] (thermosetting resin) As described above, the thermosetting resin used in the first resin layer is not particularly limited, but examples thereof include polyimide, liquid crystal polyester, epoxy resin, cyanate ester compound, maleimide compound, phenolic resin, thermosetting modified polyphenylene ether resin, benzoxazine compound, organic group-modified silicone compound, and compound having a polymerizable unsaturated group. These thermosetting resins may be used alone or in combination of two or more.

[0029] Among these thermosetting resins, the first resin layer preferably contains at least one of polyimide and liquid crystal polyester, from the viewpoint of more reliably reducing the thickness by less than 30%. Furthermore, from the viewpoint of obtaining an insulating resin layer having even better peel strength, it is more preferable that the first resin layer contains at least one of epoxy resin and phenol resin in addition to at least one of polyimide and liquid crystal polyester, and it is even more preferable that the first resin layer further contains a bismaleimide compound together with these.

[0030] -Polyimide- As the polyimide, commercially available products can be appropriately selected and used. For example, a block copolymer polyimide can be used. Examples of such block copolymer polyimides include the block copolymer polyimides described in International Publication WO2010-073952. More specifically, the block copolymer polyimide can be a copolymer polyimide having a structure in which Structure A, in which an imide oligomer composed of a first structural unit is bonded to the end of an imide oligomer composed of a second structural unit, and Structure B, in which an imide oligomer composed of the first structural unit is bonded to the end of an imide oligomer composed of the second structural unit, are alternately repeated. Here, the second structural unit is different from the first structural unit.

[0031] These block copolymer polyimides can be synthesized by a step-growth polymerization reaction in which a tetracarboxylic dianhydride and a diamine are reacted in a polar solvent to obtain an imide oligomer, and then the tetracarboxylic dianhydride and another diamine, or another tetracarboxylic dianhydride and a diamine, are added to the resulting imide oligomer. The imide oligomer composed of the first structural unit preferably has a weight-average molecular weight of approximately 5,000 to 30,000. Examples of tetracarboxylic dianhydrides include 3,4,3',4'-biphenyltetracarboxylic dianhydride. Examples of diamines include 1,3-bis(3-aminophenoxy)benzene and 2,2-bis{4-(4-aminophenoxy)phenyl}propane. These may be used alone or in combination.

[0032] Examples of polar solvents include polar solvents that dissolve polyimides, such as N-methyl-2-pyrrolidone, dimethylacetamide, dimethylformamide, dimethyl sulfoxide, sulfolane, and tetramethylurea. Ketone and ether solvents can also be used in combination. Examples of ketone solvents include methyl ethyl ketone, methyl propyl ketone, methyl isopropyl ketone, methyl butyl ketone, methyl isobutyl ketone, methyl-n-hexyl ketone, diethyl ketone, diisopropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, acetylacetone, diacetone alcohol, and cyclohexene-n-one. Examples of ether solvents include dipropyl ether, diisopropyl ether, dibutyl ether, tetrahydrofuran, tetrahydropyran, ethyl isoamyl alcohol, ethyl t-butyl ether, ethyl benzyl ether, diethylene glycol dimethyl ether, cresyl methyl ether, anisole, and phenetole. These polar solvents may be used alone or in combination of two or more.

[0033] A preferred method for removing water produced during imidization is to add a solvent that forms an azeotrope with water, such as toluene or xylene, to the reaction system to remove the water from the system. Furthermore, to promote the reaction, an amine catalyst, such as pyridine, or a two-component catalyst consisting of a base, such as pyridine, and a cyclic ester, such as γ-valerolactone, can be used. The imidization reaction temperature is preferably 120°C or higher and 200°C or lower. The solvent that forms an azeotrope with water, such as toluene or xylene, and the catalyst, such as pyridine, are finally distilled out of the system, thereby obtaining a polar solvent solution containing only the block copolymer polyimide.

[0034] The block copolymer polyimide may suitably be a block copolymer polyimide having a structural unit represented by the following formula (A) and a structural unit represented by the following formula (B), where m and n are positive numbers that fall within the range of the preferred weight-average molecular weight described below.

[0035] [ka]

[0036] The tetracarboxylic dianhydride used in the synthesis of the block copolymerized polyimide is preferably 3,4,3',4'-biphenyltetracarboxylic dianhydride. The diamine used in the synthesis of the block copolymerized polyimide is preferably 1,3-bis(3-aminophenoxy)benzene and 2,2-bis{4-(4-aminophenoxy)phenyl}propane. Furthermore, to control the molecular weight of the blocks of each structural unit, for example, in the first-stage reaction, the molar ratio of the tetracarboxylic dianhydride to the diamine may be shifted so that either one is more abundant, thereby leaving an acid anhydride skeleton or an amine skeleton at the terminal, and in the second-stage reaction, the molar ratio of the tetracarboxylic dianhydride to another diamine or the molar ratio of another tetracarboxylic dianhydride to a diamine may be shifted so that it is opposite to that in the first-stage reaction. This makes it possible to obtain a block copolymerized polyimide having the desired molecular weight.

[0037] Although not particularly limited, the weight-average molecular weight (Mw) of the block copolymer polyimide is preferably 50,000 or more and 300,000 or less, and more preferably 80,000 or more and 200,000 or less. A weight-average molecular weight of 50,000 or more can more effectively prevent the first resin layer from becoming brittle. A weight-average molecular weight of 300,000 or less can more effectively prevent coating difficulties due to increased solution viscosity. In this specification, the weight-average molecular weight is measured by GPC (gel permeation chromatography) using NMP as a solvent and converted into polystyrene.

[0038] In order to control the final molecular weight, it is also possible to synthesize the block copolymer polyimide by shifting the molar ratio of tetracarboxylic dianhydride to diamine so that one of them is more abundant. When the block copolymer polyimide has the structural unit represented by the above formula (A) and the structural unit represented by the formula (B), the molar ratio of each structural unit is preferably (structural unit represented by formula (A)):(structural unit represented by formula (B))=1:9 to 3:1, more preferably (structural unit represented by formula (A)):(structural unit represented by formula (B))=1:3 to 3:1. When the molar ratio of these structural units is within the above range, deterioration in adhesive strength and solder heat resistance can be more effectively suppressed.

[0039] The polyimide used in this embodiment may be, for example, a solvent-soluble polyimide synthesized by the manufacturing method described in JP-A-2005-15629. Specifically, the solvent-soluble polyimide can be obtained by polycondensing one or more selected from the group consisting of an aliphatic tetracarboxylic dianhydride represented by the following formula (C), an aliphatic tetracarboxylic acid represented by the following formula (D), and derivatives of the aliphatic tetracarboxylic acid (hereinafter, collectively referred to simply as "aliphatic tetracarboxylic acids") with one or more diamines in a solvent in the presence of a tertiary amine.

[0040] [ka] In the formula (C), R is a tetravalent aliphatic hydrocarbon group having 4 to 16 carbon atoms.

[0041] [ka] In formula (D), R is a tetravalent aliphatic hydrocarbon group having 4 to 16 carbon atoms, and Y1 to Y4 are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 8 carbon atoms.

[0042] In the method for producing such a solvent-soluble polyimide, approximately equimolar amounts of an aliphatic tetracarboxylic acid and a diamine are heated in a solvent in the presence of a tertiary amine to polycondense. The molar ratio of the aliphatic tetracarboxylic acid to the diamine is preferably 95 to 105 mol % relative to 100 mol % of the other.

[0043] In the production of general polyimides, tetracarboxylic dianhydrides are usually used as tetracarboxylic acids. However, in the above-mentioned method for producing solvent-soluble polyimides, practical polyimides can be produced using not only aliphatic tetracarboxylic dianhydrides but also aliphatic tetracarboxylic acids that are not anhydrides and derivatives such as esters of aliphatic tetracarboxylic acids and alcohols. Using aliphatic tetracarboxylic acids as they are is advantageous in terms of production facilities and costs.

[0044] Examples of aliphatic tetracarboxylic dianhydrides represented by formula (C) include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,4,5-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, and bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride. Examples of aliphatic tetracarboxylic acids and derivatives thereof represented by formula (D) include 1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,4,5-cyclopentanetetracarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, and bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic acid, as well as alcohol esters thereof. These may be used alone or in combination. Among these, 1,2,4,5-cyclohexanetetracarboxylic dianhydride and 1,2,4,5-cyclohexanetetracarboxylic acid are preferred.

[0045] In the method for producing the solvent-soluble polyimide, other tetracarboxylic acids and derivatives thereof can be mixed and used within a range that does not impair the solvent solubility. Examples of such tetracarboxylic acids and derivatives thereof include pyromellitic acid, 3,3',4,4'-biphenyltetracarboxylic acid, 2,3,3',4'-biphenyltetracarboxylic acid, 2,2-bis(3,4-dicarboxyphenyl)propane, 2,2-bis(2,3-dicarboxyphenyl)propane, 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis(2,3-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane, bis(3,4-dicarboxyphenyl)sulfone, bis(3,4-dicarboxyphenyl)sulfone, and bis(3,4-dicarboxyphenyl)sulfone. Examples of other tetracarboxylic acids and their derivatives include bis(2,3-dicarboxyphenyl)ether, bis(2,3-dicarboxyphenyl)ether, 3,3',4,4'-benzophenonetetracarboxylic acid, 2,2',3,3'-benzophenonetetracarboxylic acid, 4,4-(p-phenylenedioxy)diphthalic acid, 4,4-(m-phenylenedioxy)diphthalic acid, ethylenetetracarboxylic acid, 3-carboxymethyl-1,2,4-cyclopentanetricarboxylic acid, 1,1-bis(2,3-dicarboxyphenyl)ethane, and bis(2,3-dicarboxyphenyl)methane, bis(3,4-dicarboxyphenyl)methane, and derivatives thereof. The proportion of these other tetracarboxylic acids and their derivatives in the reaction substrate is preferably less than 50 mol % based on 100 mol % of all tetracarboxylic acids and their derivatives in the reaction substrate.

[0046] As the diamine, aromatic diamines having 6 to 28 carbon atoms and aliphatic diamines having 2 to 28 carbon atoms are preferred. Examples of diamines include p-phenylenediamine, m-phenylenediamine, 4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4'-diamino-3,3'-dimethylbiphenyl, 4,4'-diamino-2,2'-ditrifluoromethylbiphenyl, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfide, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2, Examples of suitable diamines include aromatic diamines such as 2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, bis[4-(3-aminophenoxy)phenyl]sulfone, and 9,9-bis(4-aminophenyl)fluorene; aliphatic diamines such as ethylenediamine, hexamethylenediamine, polyethylene glycol bis(3-aminopropyl)ether, polypropylene glycol bis(3-aminopropyl)ether, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 4,4'-diaminodicyclohexylmethane, 3(4),8(9)-bis(aminomethyl)-tricyclo[5.2.1.02,6]decane, metaxylylenediamine, paraxylylenediamine, isophoronediamine, and norbornanediamine; and siloxanediamines. These may be used alone or in combination.Among these diamines, aromatic diamines such as 4,4'-diamino-3,3'-dimethylbiphenyl, 4,4'-diamino-2,2'-ditrifluoromethylbiphenyl, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, and 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane are preferred. Among aliphatic diamines, 4,4'-diaminodicyclohexylmethane and 3(4),8(9)-bis(aminomethyl)-tricyclo[5.2.1.02,6]decane are preferred.

[0047] In the method for producing the solvent-soluble polyimide, the tertiary amine is preferably used in an amount of 0.001 mol to 1.0 mol, more preferably 0.01 mol to 0.2 mol, per mol of the aliphatic tetracarboxylic acid.

[0048] Examples of tertiary amines include trimethylamine, triethylamine, tripropylamine, tributylamine, triethanolamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, triethylenediamine, N-methylpyrrolidine, N-ethylpyrrolidine, N-methylpiperidine, N-ethylpiperidine, imidazole, pyridine, quinoline, and isoquinoline. Among these tertiary amines, triethylamine is particularly preferred.

[0049] Examples of solvents used in the method for producing the solvent-soluble polyimide include γ-butyrolactone, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N,N-dimethylformamide, dimethyl sulfoxide, hexamethylphosphoramide, tetramethylene sulfone, p-chlorophenol, m-cresol, and 2-chloro-4-hydroxytoluene. These may be used alone or in combination. Among these, γ-butyrolactone, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone are preferred, with γ-butyrolactone and N,N-dimethylacetamide being more preferred. A poor solvent for the polyimide may also be used in combination to the extent that the polymer does not precipitate. Examples of poor solvents include hexane, heptane, benzene, toluene, xylene, chlorobenzene, and o-dichlorobenzene. The amount of solvent used is preferably such that the total mass of the aliphatic tetracarboxylic acids and diamine is 1% by mass or more and 50% by mass or less, and more preferably 20% by mass or more and 45% by mass or less, of the total mass of the reaction liquid.

[0050] The method for charging the aliphatic tetracarboxylic acids and the diamine is not particularly limited, and examples thereof include a method of charging both components at once, and a method of gradually charging one of the components in a solid or solution state into a solution containing the other component (which does not have to be completely dissolved). In particular, the method of charging both components at once is advantageous in terms of productivity because it can shorten the charging time.

[0051] In order to fully exert its catalytic effect, the tertiary amine is preferably charged before the temperature reaches the target temperature, particularly at the same time as the solvent, the aliphatic tetracarboxylic acid, and the diamine are charged.

[0052] The method for adding the solvent is not particularly limited, and examples thereof include a method of adding the solvent to a reaction vessel in advance, a method of adding the solvent to a reaction vessel containing either or both of an aliphatic tetracarboxylic acid and a diamine, and a method of dissolving either an aliphatic tetracarboxylic acid and a diamine in the solvent before adding the solvent to the reaction vessel. These methods may be used alone or in combination of two or more. Furthermore, the solvent as described above can be added to the solvent-soluble polyimide solution during the reaction, while it remains in the reaction vessel after the reaction, or after it is removed from the reaction vessel after the reaction, depending on the purpose.

[0053] In this embodiment, when the first resin layer contains polyimide, its content is not particularly limited, but from the viewpoint of improving heat resistance and curability, it is preferably 10 parts by mass or more and 90 parts by mass or less, and more preferably 30 parts by mass or more and 80 parts by mass or less, per 100 parts by mass of the resin solid content in the first resin layer.

[0054] -Liquid Crystal Polyester- Liquid crystal polyester is an aromatic polyester that exhibits liquid crystallinity when melted. Known liquid crystal polyesters can be appropriately selected and used. Known liquid crystal polyesters include, for example, aromatic polyesters described in JP-A-2001-11296. Specific examples of liquid crystal polyesters include aromatic polyesters containing 90 mol % or more of a structural unit represented by the following formula (E) (hereinafter simply referred to as "structural unit (E)").

[0055] [ka]

[0056] As the aromatic polyester containing the structural unit (E), for example, polyoxybenzoate, which is essentially a homopolymer of the structural unit (E), can be used from the viewpoint of availability. Known methods can be used to produce such aromatic polyesters. Note that aromatic polyesters containing the structural unit (E) are often poorly soluble or insoluble in common solvents, and because they are poorly meltable or infusible, they do not exhibit liquid crystallinity. Therefore, aromatic polyesters containing the structural unit (E) are preferably used as powders. The powders can be obtained by pulverizing aromatic polyester resins or fibers, and the average particle size can usually be 0.1 μm to 100 μm, preferably 0.5 μm to 15 μm.

[0057] Although not particularly limited, the weight average molecular weight of the liquid crystal polyester is usually 1,000 or more and 100,000 or less, and preferably 10,000 or more and 50,000 or less.

[0058] As the liquid crystal polyester, a commercially available product can be appropriately selected and used, for example, "Econol E101-F" (trade name) manufactured by Sumitomo Chemical Co., Ltd. can be used.

[0059] In this embodiment, when the first resin layer contains a liquid crystal polyester, its content is not particularly limited, but from the viewpoint of improving heat resistance and curability, it is preferably 10 parts by mass or more and 90 parts by mass or less, and more preferably 30 parts by mass or more and 80 parts by mass or less, per 100 parts by mass of the resin solid content in the first resin layer.

[0060] -Epoxy resin- The epoxy resin is not particularly limited as long as it has two or more epoxy groups in one molecule, and any conventionally known epoxy resin can be used. The epoxy equivalent of the epoxy resin is preferably 250 g / eq or more and 850 g / eq or less, more preferably 250 g / eq or more and 450 g / eq or less, in order to improve adhesiveness and flexibility. The epoxy equivalent can be measured by a conventional method.

[0061] Examples of epoxy resins include polyoxynaphthylene-type epoxy resins, biphenyl aralkyl-type epoxy resins, naphthalene tetrafunctional-type epoxy resins, xylene-type epoxy resins, naphthol aralkyl-type epoxy resins, naphthalene aralkyl-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol A novolac-type epoxy resins, trifunctional phenol-type epoxy resins, tetrafunctional phenol-type epoxy resins, naphthalene-type epoxy resins, biphenyl-type epoxy resins, aralkyl novolac-type epoxy resins, alicyclic epoxy resins, polyol-type epoxy resins, glycidyl amine-type epoxy resins, glycidyl ester-type epoxy resins, compounds in which the double bond of a diene compound such as butadiene has been epoxidized, and compounds obtained by reacting hydroxyl-group-containing silicone resins with epichlorohydrin. Among these, from the viewpoints of plating copper adhesion and flame retardancy, the epoxy resin is preferably a polyoxynaphthylene-type epoxy resin, a biphenylaralkyl-type epoxy resin, a naphthalene tetrafunctional-type epoxy resin, a xylene-type epoxy resin, a naphtholaralkyl-type epoxy resin, or a naphthalenearalkyl-type epoxy resin. These epoxy resins can be used alone or in combination of two or more.

[0062] In this embodiment, when the first resin layer contains an epoxy resin, its content is not particularly limited, but from the viewpoint of improving heat resistance and curability, it is preferably 1 part by mass or more and 60 parts by mass or less, and more preferably 1 part by mass or more and 30 parts by mass or less, per 100 parts by mass of the resin solid content in the first resin layer.

[0063] -Cyanate ester compounds- Cyanate ester compounds have excellent properties such as chemical resistance and adhesiveness, and their excellent chemical resistance makes it possible to form a uniformly roughened surface, making them suitable for use as a component of the resin layer in this embodiment.

[0064] Examples of the cyanate ester compound include an α-naphthol aralkyl cyanate ester compound represented by the following formula (F), a novolac cyanate ester compound represented by the following formula (G), a biphenyl aralkyl cyanate ester compound represented by the following formula (H), 1,3-dicyanatobenzene, 1,4-dicyanatobenzene, 1,3,5-tricyanatobenzene, bis(3,5-dimethyl-4-cyanatophenyl)methane, 1,3-dicyanatonaphthalene, 1,4-dicyanatonaphthalene, and 1,6-dicyanatonaphthalene. , 1,8-dicyanatonaphthalene, 2,6-dicyanatonaphthalene, 2,7-dicyanatonaphthalene, 1,3,6-tricyanatonaphthalene, 4,4'-dicyanatobiphenyl, bis(4-cyanatophenyl)methane, bis(4-cyanatophenyl)propane, bis(4-cyanatophenyl)ether, bis(4-cyanatophenyl)thioether, bis(4-cyanatophenyl)sulfone, 2,2'-bis(4-cyanatophenyl)propane, and bis(3,5-dimethyl-4-cyanatophenyl)methane. These cyanate ester compounds may be used alone or in combination of two or more.

[0065] Among these, the α-naphthol aralkyl cyanate ester compound represented by formula (F), the novolac cyanate ester compound represented by formula (G), and the biphenyl aralkyl cyanate ester compound represented by formula (H) are preferred because they have excellent flame retardancy, high curability, and a low thermal expansion coefficient of the cured product.

[0066] [ka] Here, in formula (F), R 1 represents a hydrogen atom or a methyl group, and n 1 indicates an integer of 1 or greater. 1 is preferably an integer of 1 to 50.

[0067] [ka]

[0068] In formula (G), R 2 represents a hydrogen atom or a methyl group, and n 2 indicates an integer of 1 or greater. 2 is preferably an integer of 1 to 50.

[0069] [ka]

[0070] In formula (H), R 3 represents a hydrogen atom or a methyl group, and n 3 indicates an integer of 1 or greater. 3 is preferably an integer of 1 to 50.

[0071] In this embodiment, when the first resin layer contains a cyanate ester compound, its content is not particularly limited, but from the viewpoint of improving heat resistance and adhesion to the copper foil, it is preferably 1 part by mass or more and 60 parts by mass or less, and more preferably 1 part by mass or more and 30 parts by mass or less, per 100 parts by mass of the resin solid content in the first resin layer.

[0072] -Maleimide compounds- A maleimide compound can improve the moisture absorption and heat resistance of the insulating resin layer, and is therefore preferably used as a component of the resin layer in this embodiment. The maleimide compound is not particularly limited as long as it has two or more maleimide groups in one molecule, and any conventionally known maleimide compound can be used.

[0073] Examples of maleimide compounds include bismaleimide compounds such as bis(4-maleimidophenyl)methane, 2,2-bis{4-(4-maleimidophenoxy)-phenyl}propane, bis(3,5-dimethyl-4-maleimidophenyl)methane, bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, and bis(3,5-diethyl-4-maleimidophenyl)methane; and polyphenylmethane maleimide. The resin composition solution may also contain a prepolymer of these maleimide compounds, or a prepolymer of a maleimide compound and an amine compound. These maleimide compounds may be used alone or in combination of two or more.

[0074] Among these, from the viewpoint of improving heat resistance, bismaleimide compounds are preferred, and bis(3-ethyl-5-methyl-4-maleimidophenyl)methane is more preferred.

[0075] In this embodiment, when the first resin layer contains a maleimide compound, its content is not particularly limited, but from the viewpoint of improving heat resistance and adhesion to the copper foil, it is preferably 5 parts by mass or more and 75 parts by mass or less, and more preferably 5 parts by mass or more and 45 parts by mass or less, per 100 parts by mass of the resin solid content in the first resin layer.

[0076] -Phenol resin- The phenolic resin is not particularly limited as long as it has two or more phenolic hydroxyl groups in one molecule, and any conventionally known phenolic resin can be used. Examples of phenolic resins include phenol novolac resins, alkylphenol volac resins, bisphenol A novolac resins, dicyclopentadiene-type phenolic resins, Xylok-type phenolic resins, terpene-modified phenolic resins, polyvinylphenols, aralkyl-type phenolic resins, and biphenylaralkyl-type phenolic resins, which are compounds in which two or more hydrogen atoms bonded to an aromatic ring in one molecule are substituted with hydroxyl groups. These phenolic resins can be used alone or in combination of two or more.

[0077] -Thermosetting modified polyphenylene ether resin- The thermosetting modified polyphenylene ether resin is a resin obtained by blending a thermoplastic polyphenylene ether resin and an epoxy resin, dissolving the blend in a solvent such as toluene, and adding 2-ethyl-4-methylimidazole as a catalyst to crosslink the blend. The thermosetting modified polyphenylene ether resin can be used alone or in a suitable mixture of two or more types.

[0078] -Benzoxazine compounds- The benzoxazine compound is not particularly limited as long as it has an oxazine ring as a basic skeleton. In the present embodiment, the benzoxazine compound also includes compounds having a polycyclic oxazine skeleton, such as naphthoxazine compounds. The benzoxazine compound can be used alone or in an appropriate mixture of two or more types.

[0079] -Organic group modified silicone compound- The organic group-modified silicone compound is not particularly limited, and specific examples include di(methylamino)polydimethylsiloxane, di(ethylamino)polydimethylsiloxane, di(propylamino)polydimethylsiloxane, di(epoxypropyl)polydimethylsiloxane, and di(epoxybutyl)polydimethylsiloxane. These organic group-modified silicone compounds can be used alone or in appropriate mixtures of two or more.

[0080] -Compounds having polymerizable unsaturated groups- Compounds having a polymerizable unsaturated group are not particularly limited as long as they are not limited to those mentioned above, and include vinyl compounds such as ethylene, propylene, styrene, divinylbenzene, and divinylbiphenyl; (meth)acrylates of monohydric or polyhydric alcohols such as methyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, polypropylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate; epoxy (meth)acrylates such as bisphenol A-type epoxy (meth)acrylate and bisphenol F-type epoxy (meth)acrylate; and benzocyclobutene resins. These compounds having a polymerizable unsaturated group can be used alone or in combination. The term "(meth)acrylate" encompasses both methacrylate and acrylate.

[0081] [Second Resin Layer] In this embodiment, as described above, the second resin layer is typically a layer containing a resin that exhibits fluidity during press processing, and the layer itself also exhibits fluidity during press processing. The second resin layer is typically a layer in which a component that forms a laminate together with the resin layer-attached substrate is embedded from the side that contacts the surface of the second resin layer. Examples of the component include a (conductor layer) such as a circuit pattern provided on a substrate, and the conductor layer corresponds to the convex portion of the uneven shape formed together with the substrate, and is embedded in the second resin layer.

[0082] From the viewpoint of improving the embeddability of the conductor layer, the minimum melt viscosity of the second resin layer is preferably 100,000 Pa·s or less, more preferably 10 to 80,000 Pa·s, and even more preferably 30 to 60,000 Pa·s. From the same viewpoint, the minimum melt viscosity of the second resin layer is preferably lower than the minimum melt viscosity of the first resin layer, more preferably 10,000 Pa·s or more lower, even more preferably 20,000 Pa·s or more lower, and particularly preferably 40,000 Pa·s or more lower. The minimum melt viscosity of the second resin layer may be less than 50,000,000 Pa·s, or may be 49,950,000 Pa·s or less, or 49,900,000 Pa·s or less. The minimum melt viscosity of the second resin layer can be adjusted to a desired value by appropriately selecting the type of thermosetting resin contained therein, controlling the degree of hardening of the resin, or adding an inorganic filler.

[0083] The thickness of the second resin layer is not particularly limited, but from the viewpoint of improving the embeddability of the conductor layer and further enhancing the insulating properties, it is preferably 1.0 μm or more, more preferably 2.0 μm or more, and even more preferably 3.0 μm or more. On the other hand, from the viewpoint of further reducing the thickness of the substrate, the thickness of the second resin layer is preferably 25 μm or less, more preferably 20 μm or less, even more preferably 15 μm or less, even more preferably 10 μm or less, and particularly preferably 9.0 μm or less. In consideration of further improving the embeddability and insulating properties of the conductor layer as well as further reducing the thickness of the substrate, the thickness of the second resin layer is more preferably 2.0 μm to 20 μm, even more preferably 3.0 μm to 20 μm, even more preferably 4.0 μm to 15 μm, particularly preferably 5.0 μm to 10 μm, and extremely preferably 5.0 μm to 9.0 μm.

[0084] From the viewpoint of making the substrate thinner, the total thickness of the first resin layer and the second resin layer is preferably 30 μm or less, more preferably 15 μm or less, even more preferably 20 μm or less, even more preferably 15 μm or less, even more preferably 14 μm or less, particularly preferably less than 12 μm, and extremely preferably 10 μm or less. From the viewpoint of more effectively and reliably achieving the effects of the present invention even when the substrate is made thinner, the total thickness is preferably 3.0 μm or more, more preferably 5.0 μm or more, and even more preferably 6.0 μm or more. From the above viewpoint, the total thickness is more preferably 3.0 μm or more and 30 μm or less, even more preferably 3.0 μm or more and 20 μm or less, even more preferably 5.0 μm or more and 20 μm or less, even more preferably 5.0 μm or more and 15 μm or less, particularly preferably 5.0 μm or more and 14 μm or less, even more particularly preferably 5.0 μm or more and less than 12 μm, and extremely preferably 5.0 μm or more and 10 μm or less.

[0085] The second resin layer in this embodiment can be formed by known means such as coating, preferably using a varnish, which is a solution of a resin composition containing a thermosetting resin. The thermosetting resin is not particularly limited, and a desired thermosetting resin can be used depending on the desired physical properties. Furthermore, the resin composition may contain inorganic fillers and other additives, as described below, as necessary.

[0086] (thermosetting resin) As described above, the thermosetting resin used in the second resin layer is not particularly limited, but examples thereof include epoxy resins, cyanate ester compounds, maleimide compounds, phenolic resins, thermosetting modified polyphenylene ether resins, benzoxazine compounds, organic group-modified silicone compounds, and compounds having a polymerizable unsaturated group. These thermosetting resins may be the same as those exemplified above for use in the first resin layer. These thermosetting resins may be used alone or in combination of two or more.

[0087] Among these thermosetting resins, the second resin layer preferably contains at least one of an epoxy resin and a phenolic resin, more preferably both an epoxy resin and a phenolic resin, in order to obtain an insulating resin layer having even better peel strength. From the same viewpoint, the second resin layer preferably further contains a bismaleimide compound.

[0088] In this embodiment, when the second resin layer contains an epoxy resin, its content is not particularly limited, but from the viewpoint of improving heat resistance and curability, it is preferably 10 parts by mass or more and 80 parts by mass or less, and more preferably 30 parts by mass or more and 70 parts by mass or less, per 100 parts by mass of the resin solid content in the second resin layer.

[0089] In this embodiment, when the second resin layer contains a cyanate ester compound, its content is not particularly limited, but from the viewpoint of improving heat resistance and adhesion to the copper foil, it is preferably 15 parts by mass or more and 85 parts by mass or less, and more preferably 25 parts by mass or more and 65 parts by mass or less, per 100 parts by mass of the resin solid content in the second resin layer.

[0090] In this embodiment, when the second resin layer contains a maleimide compound, its content is not particularly limited, but from the viewpoint of improving heat resistance and adhesion to copper foil, it is preferably 5 parts by mass or more and 75 parts by mass or less, and more preferably 5 parts by mass or more and 45 parts by mass or less, per 100 parts by mass of the resin solid content in the second resin layer.

[0091] [Other ingredients] The first and second resin layers in this embodiment may each contain other components such as a filler, if necessary.

[0092] -Filling material- As the filler, a spherical filler is preferred from the viewpoints of low thermal expansion coefficient, moldability, packing property, and rigidity. The spherical filler is not particularly limited as long as it is a spherical filler used in the insulating layer of a printed wiring board.

[0093] Examples of spherical fillers include silicas such as magnesium hydroxide, magnesium oxide, natural silica, fused silica, amorphous silica, and hollow silica; molybdenum compounds such as molybdenum disulfide, molybdenum oxide, and zinc molybdate; alumina; aluminum nitride; glass; titanium oxide; and zirconium oxide. These spherical fillers may be used alone or in combination of two or more.

[0094] As the spherical filler, spherical silica such as spherical fused silica is preferred from the viewpoint of low thermal expansion. Commercially available spherical fused silica includes, for example, SC2050-MB, SC2500-SQ, SC4500-SQ, SO-C2, and SO-C1 (all trade names) manufactured by Admatechs Co., Ltd., and SFP-130MC (trade name) manufactured by Denki Kagaku Kogyo Co., Ltd.

[0095] The average particle size of a spherical filler such as spherical silica is not particularly limited, but is preferably 0.01 μm to 5 μm, more preferably 0.05 μm to 3 μm, even more preferably 0.1 μm to 2 μm, and particularly preferably 0.3 μm to 1.5 μm. The average particle size of spherical silica can be measured by a laser diffraction / scattering method based on Mie scattering theory. Specifically, a particle size distribution of spherical silica is created on a volume basis using a laser diffraction / scattering particle size distribution analyzer, and the median diameter is used as the average particle size. A preferred measurement sample is spherical silica dispersed in water using ultrasonic waves. An example of a laser diffraction / scattering particle size distribution analyzer that can be used is the "LA-500" (product name) manufactured by Horiba, Ltd.

[0096] In this embodiment, the content of the spherical filler is not particularly limited, but from the viewpoint of improving moldability, it is preferably 50 parts by mass or more and 500 parts by mass or less, and more preferably 100 parts by mass or more and 400 parts by mass or less, per 100 parts by mass of the resin solid content in each resin layer.

[0097] The spherical filler of the present embodiment may be surface-treated with a silane coupling agent, etc. As the silane coupling agent, the silane coupling agents described below can be used.

[0098] -Other ingredients- Each resin layer in this embodiment may contain a silane coupling agent as an additional component, for example, to improve the moisture absorption and heat resistance of the insulating resin layer in this embodiment. The silane coupling agent is not particularly limited, as long as it is a silane coupling agent generally used for surface treatment of inorganic materials. Specific examples of silane coupling agents include aminosilane-based silane coupling agents such as γ-aminopropyltriethoxysilane and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, epoxysilane-based silane coupling agents such as γ-glycidoxypropyltrimethoxysilane, vinylsilane-based silane coupling agents such as γ-methacryloxypropyltrimethoxysilane, cationic silane-based silane coupling agents such as N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride, and phenylsilane-based silane coupling agents. These silane coupling agents may be used alone or in combination of two or more.

[0099] In this embodiment, the content of the silane coupling agent in each resin layer is not particularly limited, but from the viewpoint of improving moisture absorption and heat resistance, it is preferably 0.05 parts by mass or more and 5 parts by mass or less, more preferably 0.1 parts by mass or more and 3 parts by mass or less, relative to 100 parts by mass of the spherical filler. When two or more kinds of silane coupling agents are used in combination, it is preferable that the total amount thereof is within the above range.

[0100] Each resin layer in this embodiment may contain a wetting dispersant for purposes such as improving the manufacturability of the resin layer in this embodiment. The wetting dispersant is not particularly limited as long as it is a wetting dispersant generally used in paints, etc. Specific examples of wetting dispersants include Disperbyk (registered trademark)-110, -111, -180, -161, BYK (registered trademark)-W996, -W9010, and -W903, all manufactured by BYK Japan Co., Ltd. These wetting dispersants may be used alone or in combination of two or more.

[0101] In this embodiment, the content of the wetting dispersant in each resin layer is not particularly limited, but from the viewpoint of improving the manufacturability of the resin layer in this embodiment, it is preferably 0.1 to 5 parts by mass, more preferably 0.5 to 3 parts by mass, relative to 100 parts by mass of the spherical filler. When two or more types of wetting dispersants are used in combination, it is preferable that the total amount thereof is within the above range.

[0102] Each resin layer in this embodiment may contain a curing accelerator for purposes such as adjusting the curing rate. The curing accelerator is not particularly limited and may be, for example, a commonly used curing accelerator used to accelerate the curing of epoxy resins or cyanate ester compounds. Specific examples of curing accelerators include organometallic salts containing metals such as copper, zinc, cobalt, nickel, and manganese, such as zinc octylate, cobalt naphthenate, nickel octylate, and manganese octylate; imidazoles and their derivatives, such as 2-ethyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, and 2,4,5-triphenylimidazole; and tertiary amines, such as triethylamine and tributylamine. These curing accelerators may be used alone or in combination.

[0103] In this embodiment, the content of the curing accelerator in each resin layer is not particularly limited, but in order to obtain a higher glass transition temperature, it is preferably from 0.001 to 5 parts by mass, more preferably from 0.01 to 3 parts by mass, relative to 100 parts by mass of the resin solid content in each resin layer. When two or more curing accelerators are used in combination, the total amount thereof is preferably within the above range.

[0104] The resin layer in this embodiment may contain various other polymer compounds and / or flame-retardant compounds, etc. The polymer compounds and flame-retardant compounds are not particularly limited as long as they are commonly used.

[0105] Examples of the polymer compound include various thermoplastic resins other than the above-mentioned thermosetting resins, as well as their oligomers and elastomers. Specific examples of the polymer compound include polyimide, polyamideimide, polystyrene, polyolefin, styrene-butadiene rubber (SBR), isoprene rubber (IR), butadiene rubber (BR), acrylonitrile-butadiene rubber (NBR), polyurethane, polypropylene, (meth)acrylic oligomer, (meth)acrylic polymer, and silicone resin. From the viewpoint of compatibility, acrylonitrile-butadiene rubber and styrene-butadiene rubber are preferred as the polymer compound.

[0106] The flame-retardant compound may be any flame-retardant compound other than the above-mentioned fillers, and examples thereof include phosphorus-containing compounds (e.g., phosphate esters, melamine phosphate, and phosphorus-containing epoxy resins), nitrogen-containing compounds (e.g., melamine and benzoguanamine), oxazine ring-containing compounds, and silicone compounds. These polymer compounds and flame-retardant compounds may be used alone or in combination of two or more.

[0107] The resin layer in this embodiment may contain various additives for various purposes. Specific examples of additives include ultraviolet absorbers, antioxidants, photopolymerization initiators, fluorescent brighteners, photosensitizers, dyes, pigments, thickeners, lubricants, antifoaming agents, dispersants, leveling agents, and gloss agents. These additives may be used alone or in combination of two or more.

[0108] (Resin composition) The first and second resin layers in this embodiment can each be formed using a resin composition. Each resin composition is prepared by mixing the above-mentioned thermosetting resin with other components, such as a filler, as needed. The resin composition may also be in the form of a solution in which these components are dissolved in an organic solvent, as needed. Such a resin composition solution can be suitably used as a varnish when preparing the substrate with an insulating resin layer of this embodiment, as described below. The organic solvent is not particularly limited as long as it can suitably dissolve or disperse each component and exhibit the effects of the resin layer of this embodiment. Specific examples of organic solvents include alcohols (e.g., methanol, ethanol, and propanol), ketones (e.g., acetone, methyl ethyl ketone, and methyl isobutyl ketone), amides (e.g., dimethylacetamide and dimethylformamide), and aromatic hydrocarbons (e.g., toluene and xylene). These organic solvents can be used alone or in combination of two or more.

[0109] The content of the organic solvent in the resin composition solution is not particularly limited and may be appropriately determined so as to obtain a viscosity of the solution that allows the thickness of each resin layer to fall within a desired range. The content may be, for example, 20 parts by mass or more and 1,000 parts by mass or less, 20 parts by mass or more and 500 parts by mass or less, or 30 parts by mass or more and 300 parts by mass or less, relative to 100 parts by mass of the resin composition solution.

[0110] In this embodiment, the arithmetic mean roughness (Ra) of each resin layer surface is preferably 2.0 μm or less, more preferably 0.10 μm to 1.0 μm, and even more preferably 0.15 μm to 0.50 μm. Having the arithmetic mean roughness (Ra) within the above-mentioned range improves the adhesion strength between a substrate such as copper foil and the first resin layer, or between resin layers themselves, thereby more effectively preventing layer peeling during long-term use. Depending on the purpose, each surface of the resin layer may be in contact with the substrate or with something other than the substrate (e.g., another resin layer). Regardless of the surface, it is preferable that the arithmetic mean roughness (Ra) be within the above-mentioned range. The arithmetic mean roughness of the resin layer surface can be measured using a commercially available shape measuring microscope (a laser microscope, for example, Keyence Corporation's "VK-X210" (product name)).

[0111] (Method for manufacturing substrate with insulating resin layer) The method for producing a substrate with an insulating resin layer in this embodiment is not particularly limited as long as it includes a step of laminating an insulating resin layer made of the above-described resin composition on a substrate such as copper foil. In the laminating step, for example, first, a solution (varnish) in which the resin composition is dissolved or dispersed in an organic solvent is applied to the surface of the substrate, and the solution is dried under heat and / or reduced pressure to remove the organic solvent and solidify the resin composition, thereby forming a first resin layer. As described above, the first resin layer may be in a semi-cured state or a completely cured state. Then, a solution (varnish) in which another resin composition is dissolved or dispersed in an organic solvent is applied to the surface of the substrate, and the solution is dried under heat and / or reduced pressure to remove the organic solvent and solidify the resin composition, thereby forming a second resin layer. In this case, the second resin layer is preferably in a B-stage (semi-cured state). A protective layer such as a plastic film may be provided on the second resin layer. The protective layer is appropriately removed during the laminate production process described below. The drying conditions are not particularly limited, but are such that the content of the organic solvent in each resin layer is typically 10 parts by mass or less, and preferably 5 parts by mass or less, per 100 parts by mass of each resin layer. The conditions for achieving drying vary depending on the amount of organic solvent in the varnish, but for example, in the case of a varnish containing 30 to 60 parts by mass of organic solvent per 100 parts by mass of varnish, drying can be carried out for about 3 to 10 minutes under heating conditions of 50°C to 160°C.

[0112] The method for applying the resin composition onto the substrate is not particularly limited, and known application methods such as bar coater application, air knife application, gravure application, reverse gravure application, microgravure application, micro reverse gravure coater application, die coater application, dip application, spin coat application, and spray application can be used.

[0113] <Laminate of this embodiment and manufacturing method thereof> A laminate using the substrate with an insulating resin layer of this embodiment (hereinafter, sometimes simply referred to as a "laminate") can be used, for example, to produce a coreless substrate to be provided in a printed wiring board or a substrate for mounting semiconductor elements. The coreless substrate may be a coreless substrate for a build-up material. The laminate of this embodiment is, for example, a laminate in which a conductor layer and an insulating layer formed using the substrate with an insulating resin layer of this embodiment are laminated, and may have a build-up layer. At least one of the conductor layer and the insulating layer may be a plurality of layers, and the laminate may be one in which the conductor layer and the insulating layer are alternately laminated. Here, for example, when forming an insulating layer by stacking the substrate with an insulating resin layer of this embodiment, the insulating layer can be formed by stacking the second resin layer of the substrate with an insulating resin layer of this embodiment using copper foil as the substrate so that it contacts the substrate on which the conductor layer is formed. Furthermore, when forming an insulating layer using three or more substrates with insulating resin layers, the substrate can be removed as necessary, and each resin layer can be stacked to form the insulating layer. Furthermore, when the substrate in the substrate with an insulating resin layer of this embodiment is copper foil, the copper foil may serve as the conductor layer, or the conductor layer may be formed by laminating another conductor (copper foil, etc.), such as the copper foil of a copper-clad laminate, on the insulating layer.

[0114] When the laminate of this embodiment has a build-up layer, for example, the build-up layer has a plurality of conductor layers and insulating layers, and the conductor layers are arranged between each insulating layer and on the surface of the outermost layer of the build-up layer. In this case, the number of insulating layers is not particularly limited, but can be, for example, three or four layers. Furthermore, a coreless substrate can be produced using the laminate of this embodiment. Examples of the coreless substrate include a coreless substrate having two or more layers, and may be, for example, a three-layer coreless substrate. The configuration of the coreless substrate will be described later.

[0115] In the laminate of this embodiment, from the viewpoint of realizing the demand for thinning, it is preferable that the thickness of at least one insulating layer is 1 μm or more and less than 15 μm. The thickness of the insulating layer varies depending on the various uses of the laminate, but, for example, it is more preferable that it is 1 μm or more and 14 μm or less, and even more preferable that it is 1 μm or more and 12 μm or less. Furthermore, from the same viewpoint, it is particularly preferable that the thicknesses of all insulating layers are within the above numerical range.

[0116] In the laminate, the thickness of the layer derived from the first resin layer is not particularly limited, but from the viewpoint of further thinning, it is preferably less than 10 μm. In consideration of further ensuring insulation, the thickness of the layer is more preferably 1.0 μm to 9.0 μm, more preferably 2.0 μm to 9.0 μm, even more preferably 2.5 μm to 9.0 μm, and particularly preferably 3.0 μm to 9.0 μm. The upper limit of the layer thickness may be 7.0 μm or 5.0 μm.

[0117] In the laminate, the thickness of the layer derived from the second resin layer is not particularly limited, but from the viewpoint of improving the embeddability of the conductor layer and further enhancing the insulating properties, it is preferably 2.0 μm or more, more preferably 3.0 μm or more. On the other hand, from the viewpoint of further thinning the substrate, the thickness of the layer is preferably 20 μm or less, more preferably 15 μm or less, even more preferably 10 μm or less, and particularly preferably 9.0 μm or less. In consideration of further enhancing the embeddability and insulating properties of the conductor layer as well as further thinning the substrate, the thickness of the layer is more preferably 2.0 μm to 20 μm, even more preferably 3.0 μm to 20 μm, even more preferably 4.0 μm to 15 μm, particularly preferably 5.0 μm to 10 μm, and extremely preferably 5.0 μm to 9.0 μm.

[0118] [Printed wiring board] The laminate of this embodiment can be used as a printed wiring board. Here, the printed wiring board can be obtained by using a laminate obtained from the substrate with an insulating resin layer of this embodiment as a build-up material for a metal foil-clad laminate in which the insulating resin layer, called a core substrate, has been completely cured. By using the substrate with an insulating resin layer of this embodiment and the laminate obtained therefrom, it is possible to manufacture a thin printed wiring board without using a thick support substrate (carrier substrate), for example. Furthermore, the printed wiring board obtained using the substrate with an insulating resin layer of this embodiment has even better adhesion between layers and productivity (yield rate).

[0119] A conductor circuit is formed on the surface of the metal foil-clad laminate by the metal foil of a commonly used metal foil-clad laminate and / or a conductor layer obtained by plating after peeling off the metal foil, etc. The substrate of the metal foil-clad laminate is not particularly limited, but examples thereof include a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, and a thermosetting polyphenylene ether substrate.

[0120] In this embodiment, "build-up" refers to laminating the insulating resin layer of the substrate with an insulating resin layer of this embodiment onto the metal foil and / or conductor layer on the surface of the metal foil-clad laminate.

[0121] Typically, when an insulating resin layer (resin composition layer) is laminated on a metal foil-clad laminate using an adhesive film or the like as a build-up material, the resulting printed wiring board has a cured insulating resin layer, i.e., an insulating layer, on one or both sides. A conductor layer is formed on this insulating layer, but the surface roughness of the insulating layer is low. Therefore, roughening treatment, including desmearing, is usually performed to form irregularities on the insulating layer, and then the conductor layer is formed using electroless plating and / or electrolytic plating.

[0122] However, when the substrate with an insulating resin layer of this embodiment is laminated on a metal foil-clad laminate as a build-up material, the resulting printed wiring board will have a substrate such as copper foil on one or both sides. Therefore, if the substrate is conductive, such as copper foil, a circuit pattern can be formed directly on the substrate without plating, allowing for the formation of high-density fine wiring. Furthermore, when manufacturing a printed wiring board or a substrate for mounting semiconductor elements, even if plating is performed after etching the substrate, the substrate surface is transferred to the insulating resin layer, thereby improving adhesion between the insulating layer and the plating.

[0123] In the manufacture of printed wiring boards, holes such as via holes and / or through holes are formed as needed to electrically connect the various conductor layers. After this hole formation, a roughening treatment including a desmearing treatment is performed. When the surface of the printed wiring board is protected by a conductor layer such as copper foil that has excellent adhesion to the insulating layer, roughening of the surface of the printed wiring board can be suppressed even when the roughening treatment is performed.

[0124] Drilling is typically performed using a mechanical drill, carbon dioxide laser, UV laser, YAG laser, or the like. When the surface of a printed wiring board is protected by a conductive layer such as copper foil, the energy of the drill or laser can be increased. Therefore, according to this embodiment, inorganic materials such as glass fibers exposed on the surface of the hole during drilling can be effectively removed. The roughening treatment typically includes a swelling step, a surface roughening and smear dissolution step, and a neutralization step.

[0125] In the swelling step, the surface of the insulating layer is swelled using a swelling agent. The swelling agent is not particularly limited as long as it improves the wettability of the surface of the insulating layer and can swell the surface of the insulating layer to an extent that oxidative decomposition is promoted in the subsequent surface roughening and smear dissolution steps. Examples of the swelling agent include an alkaline solution and a surfactant solution.

[0126] In the surface roughening and smear dissolving step, an oxidizing agent is used to roughen the surface of the insulating layer and dissolve the smear. Examples of the oxidizing agent include an alkaline permanganate solution, and preferred examples include an aqueous potassium permanganate solution and an aqueous sodium permanganate solution. This oxidizing agent treatment is called wet desmearing, but other known roughening treatments, such as dry desmearing by plasma treatment or UV treatment, mechanical polishing with a buff or the like, and sandblasting, may be appropriately combined with the wet desmearing.

[0127] In the neutralization step, the oxidizing agent used in the previous step is neutralized with a reducing agent. Examples of the reducing agent include amine-based reducing agents. Specific examples of suitable reducing agents include acidic aqueous solutions such as an aqueous solution of hydroxylamine sulfate, an aqueous solution of ethylenediaminetetraacetic acid, and an aqueous solution of nitrilotriacetic acid.

[0128] In this embodiment, after providing via holes and / or through holes or after desmearing the inside of the via holes and / or through holes, it is preferable to perform metal plating to electrically connect the conductor layers. In this embodiment, even if metal plating is performed, the surface of the conductor layer is transferred to the insulating layer, so that the adhesion between the insulating layer and the metal plating is improved.

[0129] The metal plating method is not particularly limited, and any metal plating method used in the manufacture of conventional multilayer printed wiring boards can be used as appropriate. The metal plating method and the type of chemical used for plating are not particularly limited, and any metal plating method and chemical used in the manufacture of conventional multilayer printed wiring boards can be used as appropriate. The chemical used for the metal plating may be a commercially available product. The metal plating method is not particularly limited, and examples include treatment with a degreasing solution, treatment with a soft etching solution, acid cleaning, treatment with a pre-dip solution, treatment with a catalyst solution, treatment with an accelerator solution, treatment with a chemical copper solution, acid cleaning, and immersion in a copper sulfate solution followed by application of an electric current.

[0130] Furthermore, when a build-up is performed using a substrate with a semi-cured insulating resin layer, a printed wiring board can usually be obtained by completely curing the semi-cured insulating resin layer by subjecting it to a heat treatment or the like. In this embodiment, another substrate with an insulating resin layer may be further laminated on the obtained printed wiring board.

[0131] The lamination method by the build-up method is not particularly limited, but a vacuum pressure laminator can be suitably used. In this case, the substrate with an insulating resin layer of this embodiment can be laminated onto a metal foil-clad laminate via an elastic body such as rubber. The lamination conditions are not particularly limited as long as they are conditions used in laminating ordinary printed wiring boards. For example, a temperature of 70°C to 140°C, a pressure of 1 kgf / cm 2 More than 11kgf / cm 2 Examples of suitable conditions include a contact pressure in the range below and a reduced atmospheric pressure of 20 hPa or less. After lamination, the laminated insulating resin layer may be smoothed by heat pressing with a metal plate. Lamination and smoothing can be performed continuously using a commercially available vacuum pressure laminator. After lamination or smoothing, the insulating resin layer can be heated and thermally cured to completely cure it. The thermal curing conditions vary depending on the types of components contained in the resin composition, but typically include a curing temperature of 100°C to 300°C and a pressure of 0.5 kgf / cm. 2 More than 100kgf / cm 2 or less (approximately 9.8 kPa or more and approximately 9.8 MPa or less), and the curing time is 30 seconds to 5 hours.

[0132] In this embodiment, methods for forming a circuit pattern on the copper foil or conductor layer on one or both sides of the printed wiring board include a semi-additive method, a full-additive method, and a subtractive method. Among these, the semi-additive method is preferred from the viewpoint of forming a fine wiring pattern.

[0133] An example of a method for forming a circuit pattern using a semi-additive method is a method in which electrolytic plating is selectively performed using a plating resist (pattern plating), followed by peeling off the plating resist and etching the entire surface appropriately to form a wiring pattern. When forming a circuit pattern using a semi-additive method, electroless plating and electrolytic plating are performed in combination, and in this case, it is preferable to dry the substrate after both the electroless plating and the electrolytic plating. The drying after electroless plating is not particularly limited, but is preferably performed at a temperature of 80°C or higher and 180°C or lower for 10 to 120 minutes. The drying after electrolytic plating is not particularly limited, but is preferably performed at a temperature of 130°C or higher and 220°C or lower for 10 to 120 minutes. Copper plating is preferred as the plating.

[0134] The insulating layer formed using the substrate with a resin layer of this embodiment has excellent plating adhesion. Here, "plating adhesion" can be evaluated by, for example, using a sample on which a conductor layer (plated copper) with a thickness of 18 μm is formed, measuring the adhesive strength of the conductor layer three times in accordance with JIS C6481 (5.7. (Peel strength)) and calculating the average value. Note that for samples that swell due to drying after electrolytic copper plating, evaluation is performed using the non-swelled portion. "Plating adhesion" is preferably 0.1 kN / m or more, more preferably 0.2 kN / m or more, and even more preferably 0.3 kN / m or more.

[0135] An example of a method for forming a circuit pattern using a subtractive method is a technique in which a circuit pattern is formed by selectively removing a conductor layer using an etching resist. Specifically, for example, a circuit pattern is formed as follows: A dry film resist (e.g., RD-1225 (trade name) manufactured by Hitachi Chemical) is laminated onto the entire surface of a copper foil at a temperature of 110±10°C and a pressure of 0.50±0.02 MPa. Next, the copper foil is exposed to light along the circuit pattern and masked. The dry film resist is then developed using a 1% aqueous sodium carbonate solution, and finally stripped using an amine-based resist stripper. This allows a circuit pattern to be formed on the copper foil.

[0136] In this embodiment, an insulating layer and / or a conductor layer may be further laminated on the printed wiring board to obtain a multilayer printed wiring board. The multilayer printed wiring board may have a circuit board as an inner layer. The insulating resin layer in the substrate with an insulating resin layer of this embodiment constitutes one of the insulating layers and conductor layers of the multilayer printed wiring board.

[0137] The lamination method is not particularly limited, and methods commonly used in lamination molding of ordinary printed wiring boards can be used. Examples of lamination methods include a multi-stage press, a multi-stage vacuum press, a laminator, a vacuum laminator, and an autoclave molding machine. The temperature during lamination is not particularly limited, but is, for example, 100°C or higher and 300°C or lower. The pressure during lamination is not particularly limited, but is, for example, 0.1 kgf / cm. 2 More than 100kgf / cm 2 or less (about 9.8 kPa or more and about 9.8 MPa or less). The heating time during lamination is not particularly limited, but is, for example, 30 seconds to 5 hours. If necessary, post-curing may be performed at a temperature range of, for example, 150°C to 300°C to adjust the degree of curing.

[0138] [Semiconductor element mounting board] As described above, the laminate of this embodiment can be used as a semiconductor device mounting substrate. A semiconductor device mounting substrate can be produced, for example, by laminating the insulating resin layer-equipped substrate of this embodiment on a metal foil-clad laminate, and then masking and patterning a substrate such as copper foil on one side or the surface of the resulting laminate to form a circuit pattern. The masking and patterning can be performed using known masking and patterning methods used in the manufacture of printed wiring boards, and are not particularly limited, but it is preferable to form the circuit pattern by the subtractive method described above. The circuit pattern may be formed on only one side of the laminate, or on both sides.

[0139] [Multilayer coreless substrate (multilayer printed wiring board)] The laminate of this embodiment can be a coreless substrate. An example of a coreless substrate is a multilayer coreless substrate. The multilayer coreless substrate has, for example, a plurality of insulating layers, each consisting of a first insulating layer and one or more second insulating layers laminated on one side of the first insulating layer, a first conductor layer disposed between each of the plurality of insulating layers, and a second conductor layer disposed on the surface of the outermost layer of the plurality of insulating layers, and the first insulating layer and the second insulating layer each comprise a cured product of the insulating resin layer in the substrate with an insulating resin layer of this embodiment. A specific example of a multilayer coreless substrate will be described with reference to FIG. 2. FIG. 2 is a schematic diagram showing an example of a multilayer coreless substrate of this embodiment. The multilayer coreless substrate 100 shown in Fig. 2 includes a first insulating layer 111 and two second insulating layers 112 stacked on one side of the first insulating layer 111 (toward the bottom surface in the figure), and the first insulating layer 111 and the two second insulating layers 112 are each formed using the insulating resin layer in one of the base materials with an insulating resin layer of this embodiment. The multilayer coreless substrate 100 shown in Fig. 2 also has a plurality of conductor layers, including a first conductor layer 113 disposed between each of the plurality of insulating layers (insulating layers 111 and 112) and a second conductor layer 113 disposed as the outermost layer of the plurality of insulating layers (insulating layers 111 and 112). [Example]

[0140] The present invention will be explained in more detail below using examples and comparative examples, but the present invention is not limited to these examples in any way.

[0141] [Example 1] 60 parts by weight of block copolymer polyimide (product name: YN-003N, manufactured by PI Technical Research Institute), 40 parts by weight of 2,2-bis-{4-(4-maleimidophenoxy)phenyl}propane (product name: BMI-80, manufactured by K.I. Chemical Co., Ltd.), 60 parts by weight of spherical silica (product name: SO-C1, average particle size 0.3 μm, manufactured by Admatechs Co., Ltd.), and 0.2 parts by weight of a wetting and dispersing agent (product name: BYK-W903, manufactured by BYK Japan Co., Ltd.) were mixed and then diluted with N-methyl-2-pyrrolidone (hereinafter referred to as "NMP") to obtain a resin composition solution, Varnish A. The resulting Varnish A was applied to the matte side of 12 μm-thick copper foil (product name: 3EC-M2S-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) using a bar coater to obtain a coating film. The coating film was then dried by heating at 180° C. for 10 minutes to obtain a resin-coated copper foil having a first resin layer formed on the copper foil.

[0142] Next, 36 parts by mass of biphenylaralkyl phenolic resin (product name: KAYAHARD GPH-103, hydroxyl equivalent: 231 g / eq., manufactured by Nippon Kayaku Co., Ltd.), 39 parts by mass of biphenylaralkyl epoxy resin (product name: NC-3000-FH, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 320 g / eq.), 7 parts by mass of naphthalenearalkyl epoxy resin (product name: HP-9900, epoxy equivalent: 274 g / eq., manufactured by DIC Corporation), 18 parts by mass of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane (product name: BMI-70, manufactured by K.I. Kasei Co., Ltd.), and 0.5 parts by mass of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) were blended and mixed, and then diluted with methyl ethyl ketone to obtain varnish B, a solution of the resin composition. The obtained varnish B was applied to the first resin layer side of the resin-coated copper foil obtained by the above method using a bar coater to obtain a coating film. The coating film was then heated and dried at 150°C for 10 minutes to obtain a substrate (resin sheet) with an insulating resin layer having a first resin layer and a second resin layer in this order from the substrate side. The thickness of the first resin layer was 2.5 μm, and the thickness of the second resin layer was 5.4 μm.

[0143] [Example 2] 60 parts by weight of block copolymer polyimide (product name: YN-003N, manufactured by PI Technical Research Institute), 40 parts by weight of 2,2-bis-{4-(4-maleimidophenoxy)phenyl}propane (product name: BMI-80, manufactured by K.I. Chemical Co., Ltd.), 60 parts by weight of spherical silica (product name: SO-C1, average particle size 0.3 μm, manufactured by Admatechs Co., Ltd.), and 0.2 parts by weight of a wetting and dispersing agent (product name: BYK-W903, manufactured by BYK Japan Co., Ltd.) were mixed and then diluted with NMP to obtain a resin composition solution, Varnish A. The resulting Varnish A was applied to the matte side of 12 μm-thick copper foil (product name: 3EC-M2S-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) using a bar coater to obtain a coating film. The coating film was then dried by heating at 180° C. for 10 minutes to obtain a resin-coated copper foil having a first resin layer formed on the copper foil.

[0144] Next, 36 parts by mass of biphenyl aralkyl phenol resin (product name: KAYAHARD GPH-103, hydroxyl group equivalent: 231 g / eq., manufactured by Nippon Kayaku Co., Ltd.), 39 parts by mass of biphenyl aralkyl epoxy resin (product name: NC-3000-FH, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 320 g / eq.), 7 parts by mass of naphthalene aralkyl epoxy resin (product name: HP-9900, epoxy equivalent: 274 g / eq., manufactured by DIC Corporation), 18 parts by mass of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane (product name: BMI-70, manufactured by K.I. Kasei Co., Ltd.), 300 parts by mass of slurry silica (product name: SC2050-MB, average particle size 0.7 μm, manufactured by Admatechs Co., Ltd.), and styrene butadiene rubber (product name: JSR 20 parts by weight of a wetting and dispersing agent (TR2003, manufactured by JSR Corporation), 1 part by weight of a wetting and dispersing agent 1 (product name: DISPERBYK-161, manufactured by BYK Japan), 2 parts by weight of a wetting and dispersing agent 2 (product name: DISPERBYK-111, manufactured by BYK Japan), 1 part by weight of a silane coupling agent (product name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.), and 0.5 parts by weight of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) were blended and mixed, and then diluted with methyl ethyl ketone to obtain a resin composition solution, Varnish B. The resulting Varnish B (resin composition) was applied to the first resin layer side of the resin-coated copper foil obtained by the above method using a bar coater to obtain a coating film. The coating film was then heated and dried at 150°C for 10 minutes to obtain a substrate (resin sheet) with an insulating resin layer, having a first resin layer and a second resin layer in that order from the substrate side. The first resin layer had a thickness of 2.5 μm, and the second resin layer had a thickness of 5.1 μm.

[0145] [Example 3] 60 parts by weight of block copolymer polyimide (product name: YN-003N, manufactured by PI Technical Research Institute), 40 parts by weight of 2,2-bis-{4-(4-maleimidophenoxy)phenyl}propane (product name: BMI-80, manufactured by K.I. Chemical Co., Ltd.), 60 parts by weight of spherical silica (product name: SO-C1, average particle size 0.3 μm, manufactured by Admatechs Co., Ltd.), and 0.2 parts by weight of a wetting and dispersing agent (product name: BYK-W903, manufactured by BYK Japan Co., Ltd.) were mixed and then diluted with NMP to obtain a resin composition, varnish A. The resulting varnish A was applied to the matte side of 12 μm-thick copper foil (product name: 3EC-M2S-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) using a bar coater to obtain a coating film. The coating film was then dried by heating at 180° C. for 10 minutes to obtain a resin-coated copper foil having a first resin layer formed on the copper foil.

[0146] Next, 36 parts by mass of biphenyl aralkyl phenol resin (product name: KAYAHARD GPH-103, hydroxyl group equivalent: 231 g / eq., manufactured by Nippon Kayaku Co., Ltd.), 39 parts by mass of biphenyl aralkyl epoxy resin (product name: NC-3000-FH, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 320 g / eq.), 7 parts by mass of naphthalene aralkyl epoxy resin (product name: HP-9900, epoxy equivalent: 274 g / eq., manufactured by DIC Corporation), 18 parts by mass of bis(3-ethyl-5-methyl-4-maleimidodiphenyl)methane (product name: BMI-70, manufactured by K.I. Kasei Co., Ltd.), 420 parts by mass of slurry silica (product name: SC2050-MB, average particle size: 0.7 μm, manufactured by Admatechs Co., Ltd.), and styrene butadiene rubber (product name: JSR 20 parts by weight of a wetting and dispersing agent (TR2003, manufactured by JSR Corporation), 1 part by weight of a wetting and dispersing agent 1 (product name: DISPERBYK-161, manufactured by BYK Japan Co., Ltd.), 2 parts by weight of a wetting and dispersing agent 2 (product name: DISPERBYK-111, manufactured by BYK Japan Co., Ltd.), 1 part by weight of a silane coupling agent (product name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.), and 0.5 parts by weight of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) were blended and mixed, and then diluted with methyl ethyl ketone to obtain a resin composition solution, Varnish B. The resulting Varnish B was applied to the first resin layer side of the resin-coated copper foil obtained by the above method using a bar coater to obtain a coating film. The coating film was then heated and dried at 150°C for 10 minutes to obtain a substrate (resin sheet) with an insulating resin layer, having a first resin layer and a second resin layer in that order from the substrate side. The first resin layer had a thickness of 2.5 μm, and the second resin layer had a thickness of 4.7 μm.

[0147] [Example 4] 50 parts by weight of block copolymer polyimide (product name: YN-003N, manufactured by PI Technical Research Institute), 50 parts by weight of 2,2-bis-{4-(4-maleimidophenoxy)phenyl}propane (product name: BMI-80, manufactured by K.I. Chemical Co., Ltd.), 60 parts by weight of spherical silica (product name: SO-C1, average particle size 0.3 μm, manufactured by Admatechs Co., Ltd.), and 0.2 parts by weight of a wetting and dispersing agent (product name: BYK-W903, manufactured by BYK Japan Co., Ltd.) were mixed and then diluted with NMP to obtain a resin composition solution, Varnish A. The resulting Varnish A was applied to the matte side of 12 μm-thick copper foil (product name: 3EC-M2S-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) using a bar coater to obtain a coating film. The coating film was then dried by heating at 180° C. for 10 minutes to obtain a resin-coated copper foil having a first resin layer formed on the copper foil.

[0148] Next, 36 parts by mass of biphenyl aralkyl phenol resin (product name: KAYAHARD GPH-103, hydroxyl group equivalent: 231 g / eq., manufactured by Nippon Kayaku Co., Ltd.), 39 parts by mass of biphenyl aralkyl epoxy resin (product name: NC-3000-FH, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 320 g / eq.), 7 parts by mass of naphthalene aralkyl epoxy resin (product name: HP-9900, epoxy equivalent: 274 g / eq., manufactured by DIC Corporation), 18 parts by mass of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane (product name: BMI-70, manufactured by K.I. Kasei Co., Ltd.), 300 parts by mass of slurry silica (product name: SC2050-MB, average particle size 0.7 μm, manufactured by Admatechs Co., Ltd.), and styrene butadiene rubber (product name: JSR 20 parts by weight of a wetting and dispersing agent (TR2003, manufactured by JSR Corporation), 1 part by weight of a wetting and dispersing agent 1 (product name: DISPERBYK-161, manufactured by BYK Japan), 2 parts by weight of a wetting and dispersing agent 2 (product name: DISPERBYK-111, manufactured by BYK Japan), 1 part by weight of a silane coupling agent (product name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.), and 0.5 parts by weight of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) were blended and mixed, and then diluted with methyl ethyl ketone to obtain a resin composition solution, Varnish B. The resulting Varnish B (resin composition) was applied to the first resin layer side of the resin-coated copper foil obtained by the above method using a bar coater to obtain a coating film. The coating film was then heated and dried at 150°C for 10 minutes to obtain a substrate (resin sheet) with an insulating resin layer, having a first resin layer and a second resin layer in that order from the substrate side. The first resin layer had a thickness of 2.5 μm, and the second resin layer had a thickness of 5.1 μm.

[0149] [Example 5] 60 parts by weight of block copolymer polyimide (product name: YN-003N, manufactured by PI Technical Research Institute), 40 parts by weight of 2,2-bis-{4-(4-maleimidophenoxy)phenyl}propane (product name: BMI-80, manufactured by K.I. Chemical Co., Ltd.), 60 parts by weight of spherical silica (product name: SO-C1, average particle size 0.3 μm, manufactured by Admatechs Co., Ltd.), and 0.2 parts by weight of a wetting and dispersing agent (product name: BYK-W903, manufactured by BYK Japan Co., Ltd.) were mixed and then diluted with NMP to obtain a resin composition solution, Varnish A. The resulting Varnish A was applied to the matte side of 12 μm-thick copper foil (product name: 3EC-M2S-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) using a bar coater to obtain a coating film. The coating film was then dried by heating at 180° C. for 10 minutes to obtain a resin-coated copper foil having a first resin layer formed on the copper foil.

[0150] Next, 36 parts by mass of biphenylaralkyl phenolic resin (product name: KAYAHARD GPH-103, hydroxyl equivalent: 231 g / eq., manufactured by Nippon Kayaku Co., Ltd.), 39 parts by mass of biphenylaralkyl epoxy resin (product name: NC-3000-FH, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 320 g / eq.), 7 parts by mass of naphthalenearalkyl epoxy resin (product name: HP-9900, epoxy equivalent: 274 g / eq., manufactured by DIC Corporation), 18 parts by mass of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane (product name: BMI-70, manufactured by K.I. Kasei Co., Ltd.), and 0.5 parts by mass of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) were blended and mixed, and then diluted with methyl ethyl ketone to obtain varnish B, a solution of the resin composition. The obtained varnish B was applied to the first resin layer side of the resin-coated copper foil obtained by the above method using a bar coater to obtain a coating film. The coating film was then heated and dried at 150°C for 10 minutes to obtain a substrate (resin sheet) with an insulating resin layer having a first resin layer and a second resin layer in this order from the substrate side. The thickness of the first resin layer was 2.5 μm, and the thickness of the second resin layer was 8.9 μm.

[0151] [Example 6] Biphenyl aralkyl epoxy resin (product name: NC-3000-FH, manufactured by Nippon Kayaku Co., Ltd.) 40 parts by mass, 2,2-bis-{4-(4-maleimidophenoxy)phenyl}propane (product name: BMI-80, manufactured by K.I. Kasei Co., Ltd.) 60 parts by mass, spherical silica (product name: SO-C1, average particle size 0.3 μm, manufactured by Admatechs Co., Ltd.) 60 parts by mass, wetting and dispersing agent (product name: BYK-W903, manufactured by BYK-Chemie Co., Ltd.) 0.2 parts by mass of a resin composition solution (manufactured by Mitsui Mining & Smelting Co., Ltd.) was blended and mixed, and then diluted with NMP to obtain a resin composition solution, Varnish A. The obtained Varnish A was applied to the matte side of a 12 μm thick copper foil (product name: 3EC-M2S-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) using a bar coater to obtain a coating film. The coating film was then heated and dried at 200°C for 10 minutes to obtain a resin-coated copper foil having a first resin layer formed on the copper foil.

[0152] Next, 36 parts by mass of biphenylaralkyl phenolic resin (product name: KAYAHARD GPH-103, hydroxyl equivalent: 231 g / eq., manufactured by Nippon Kayaku Co., Ltd.), 39 parts by mass of biphenylaralkyl epoxy resin (product name: NC-3000-FH, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 320 g / eq.), 7 parts by mass of naphthalenearalkyl epoxy resin (product name: HP-9900, epoxy equivalent: 274 g / eq., manufactured by DIC Corporation), 18 parts by mass of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane (product name: BMI-70, manufactured by K.I. Kasei Co., Ltd.), and 0.5 parts by mass of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) were blended and mixed, and then diluted with methyl ethyl ketone to obtain varnish B, a solution of the resin composition. The obtained varnish B was applied to the first resin layer side of the resin-coated copper foil obtained by the above method using a bar coater to obtain a coating film. The coating film was then heated and dried at 150°C for 10 minutes to obtain a substrate (resin sheet) with an insulating resin layer having a first resin layer and a second resin layer in this order from the substrate side. The thickness of the first resin layer was 2.7 μm, and the thickness of the second resin layer was 5.4 μm.

[0153] [Example 7] 60 parts by weight of block copolymer polyimide (product name: YN-003N, manufactured by PI Technical Research Institute), 40 parts by weight of 2,2-bis-{4-(4-maleimidophenoxy)phenyl}propane (product name: BMI-80, manufactured by K.I. Chemical Co., Ltd.), 60 parts by weight of spherical silica (product name: SO-C1, average particle size 0.3 μm, manufactured by Admatechs Co., Ltd.), and 0.2 parts by weight of a wetting and dispersing agent (product name: BYK-W903, manufactured by BYK Japan Co., Ltd.) were mixed and then diluted with NMP to obtain a resin composition solution, Varnish A. The resulting Varnish A was applied to the matte side of 12 μm-thick copper foil (product name: 3EC-M2S-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) using a bar coater to obtain a coating film. The coating film was then dried by heating at 180° C. for 10 minutes to obtain a resin-coated copper foil having a first resin layer formed on the copper foil.

[0154] Next, 36 parts by mass of biphenyl aralkyl phenol resin (product name: KAYAHARD GPH-103, hydroxyl group equivalent: 231 g / eq., manufactured by Nippon Kayaku Co., Ltd.), 39 parts by mass of biphenyl aralkyl epoxy resin (product name: NC-3000-FH, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 320 g / eq.), 7 parts by mass of naphthalene aralkyl epoxy resin (product name: HP-9900, epoxy equivalent: 274 g / eq., manufactured by DIC Corporation), 18 parts by mass of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane (product name: BMI-70, manufactured by K.I. Kasei Co., Ltd.), 350 parts by mass of slurry silica (product name: SC2050-MB, average particle size: 0.7 μm, manufactured by Admatechs Co., Ltd.), and styrene butadiene rubber (product name: JSR 20 parts by weight of a wetting and dispersing agent (TR2003, manufactured by JSR Corporation), 1 part by weight of a wetting and dispersing agent 1 (product name: DISPERBYK-161, manufactured by BYK Japan), 2 parts by weight of a wetting and dispersing agent 2 (product name: DISPERBYK-111, manufactured by BYK Japan), 1 part by weight of a silane coupling agent (product name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.), and 0.5 parts by weight of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) were blended and mixed, and then diluted with methyl ethyl ketone to obtain a resin composition solution, Varnish B. The resulting Varnish B (resin composition) was applied to the first resin layer side of the resin-coated copper foil obtained by the above method using a bar coater to obtain a coating film. The coating film was then heated and dried at 150°C for 10 minutes to obtain a substrate (resin sheet) with an insulating resin layer, having a first resin layer and a second resin layer in that order from the substrate side. The first resin layer had a thickness of 2.5 μm, and the second resin layer had a thickness of 4.8 μm.

[0155] [Example 8] 60 parts by weight of block copolymer polyimide (product name: YN-003N, manufactured by PI Technical Research Institute), 40 parts by weight of 2,2-bis-{4-(4-maleimidophenoxy)phenyl}propane (product name: BMI-80, manufactured by K.I. Chemical Co., Ltd.), 30 parts by weight of spherical silica (product name: SO-C1, average particle size 0.3 μm, manufactured by Admatechs Co., Ltd.), and 0.2 parts by weight of a wetting and dispersing agent (product name: BYK-W903, manufactured by BYK Japan Co., Ltd.) were mixed and then diluted with NMP to obtain a resin composition solution, Varnish A. The resulting Varnish A was applied to the matte side of 12 μm-thick copper foil (product name: 3EC-M2S-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) using a bar coater to obtain a coating film. The coating film was then dried by heating at 180° C. for 10 minutes to obtain a resin-coated copper foil having a first resin layer formed on the copper foil.

[0156] Next, 36 parts by mass of biphenyl aralkyl phenol resin (product name: KAYAHARD GPH-103, hydroxyl group equivalent: 231 g / eq., manufactured by Nippon Kayaku Co., Ltd.), 39 parts by mass of biphenyl aralkyl epoxy resin (product name: NC-3000-FH, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 320 g / eq.), 7 parts by mass of naphthalene aralkyl epoxy resin (product name: HP-9900, epoxy equivalent: 274 g / eq., manufactured by DIC Corporation), 18 parts by mass of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane (product name: BMI-70, manufactured by K.I. Kasei Co., Ltd.), 350 parts by mass of slurry silica (product name: SC2050-MB, average particle size: 0.7 μm, manufactured by Admatechs Co., Ltd.), and styrene butadiene rubber (product name: JSR 20 parts by weight of a wetting and dispersing agent (TR2003, manufactured by JSR Corporation), 1 part by weight of a wetting and dispersing agent 1 (product name: DISPERBYK-161, manufactured by BYK Japan), 2 parts by weight of a wetting and dispersing agent 2 (product name: DISPERBYK-111, manufactured by BYK Japan), 1 part by weight of a silane coupling agent (product name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.), and 0.5 parts by weight of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) were blended and mixed, and then diluted with methyl ethyl ketone to obtain a resin composition solution, Varnish B. The resulting Varnish B (resin composition) was applied to the first resin layer side of the resin-coated copper foil obtained by the above method using a bar coater to obtain a coating film. The coating film was then heated and dried at 150°C for 10 minutes to obtain a substrate (resin sheet) with an insulating resin layer, having a first resin layer and a second resin layer in that order from the substrate side. The first resin layer had a thickness of 1.8 μm, and the second resin layer had a thickness of 3.2 μm. [Example 9] 60 parts by weight of block copolymer polyimide (product name: YN-003N, manufactured by PI Technical Research Institute), 40 parts by weight of 2,2-bis-{4-(4-maleimidophenoxy)phenyl}propane (product name: BMI-80, manufactured by K.I. Chemical Co., Ltd.), 30 parts by weight of spherical silica (product name: SO-C1, average particle size 0.3 μm, manufactured by Admatechs Co., Ltd.), and 0.2 parts by weight of a wetting and dispersing agent (product name: BYK-W903, manufactured by BYK Japan Co., Ltd.) were mixed and then diluted with NMP to obtain a resin composition solution, Varnish A. The resulting Varnish A was applied to the matte side of 12 μm-thick copper foil (product name: 3EC-M2S-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) using a bar coater to obtain a coating film. The coating film was then dried by heating at 180° C. for 10 minutes to obtain a resin-coated copper foil having a first resin layer formed on the copper foil.

[0157] Next, 36 parts by mass of biphenyl aralkyl phenol resin (product name: KAYAHARD GPH-103, hydroxyl group equivalent: 231 g / eq., manufactured by Nippon Kayaku Co., Ltd.), 39 parts by mass of biphenyl aralkyl epoxy resin (product name: NC-3000-FH, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 320 g / eq.), 7 parts by mass of naphthalene aralkyl epoxy resin (product name: HP-9900, epoxy equivalent: 274 g / eq., manufactured by DIC Corporation), 18 parts by mass of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane (product name: BMI-70, manufactured by K.I. Kasei Co., Ltd.), 350 parts by mass of slurry silica (product name: SC2050-MB, average particle size: 0.7 μm, manufactured by Admatechs Co., Ltd.), and styrene butadiene rubber (product name: JSR 20 parts by weight of a wetting and dispersing agent (TR2003, manufactured by JSR Corporation), 1 part by weight of a wetting and dispersing agent 1 (product name: DISPERBYK-161, manufactured by BYK Japan), 2 parts by weight of a wetting and dispersing agent 2 (product name: DISPERBYK-111, manufactured by BYK Japan), 1 part by weight of a silane coupling agent (product name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.), and 0.5 parts by weight of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) were blended and mixed, and then diluted with methyl ethyl ketone to obtain a resin composition solution, Varnish B. The resulting Varnish B (resin composition) was applied to the first resin layer side of the resin-coated copper foil obtained by the above method using a bar coater to obtain a coating film. The coating film was then heated and dried at 150°C for 10 minutes to obtain a substrate (resin sheet) with an insulating resin layer, having a first resin layer and a second resin layer in that order from the substrate side. The first resin layer had a thickness of 1.8 μm, and the second resin layer had a thickness of 1.6 μm.

[0158] [Example 10] 60 parts by weight of block copolymer polyimide (product name: YN-003N, manufactured by PI Technical Research Institute), 40 parts by weight of 2,2-bis-{4-(4-maleimidophenoxy)phenyl}propane (product name: BMI-80, manufactured by K.I. Chemical Co., Ltd.), 60 parts by weight of spherical silica (product name: SO-C1, average particle size 0.3 μm, manufactured by Admatechs Co., Ltd.), and 0.2 parts by weight of a wetting and dispersing agent (product name: BYK-W903, manufactured by BYK Japan Co., Ltd.) were mixed and then diluted with NMP to obtain a resin composition solution, Varnish A. The resulting Varnish A was applied to the matte side of 12 μm-thick copper foil (product name: 3EC-M2S-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) using a bar coater to obtain a coating film. The coating film was then dried by heating at 180° C. for 10 minutes to obtain a resin-coated copper foil having a first resin layer formed on the copper foil.

[0159] Next, 36 parts by mass of biphenylaralkyl phenolic resin (product name: KAYAHARD GPH-103, hydroxyl equivalent: 231 g / eq., manufactured by Nippon Kayaku Co., Ltd.), 39 parts by mass of biphenylaralkyl epoxy resin (product name: NC-3000-FH, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 320 g / eq.), 7 parts by mass of naphthalenearalkyl epoxy resin (product name: HP-9900, epoxy equivalent: 274 g / eq., manufactured by DIC Corporation), 18 parts by mass of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane (product name: BMI-70, manufactured by K.I. Kasei Co., Ltd.), and 0.5 parts by mass of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) were blended and mixed, and then diluted with methyl ethyl ketone to obtain varnish B, a solution of the resin composition. The obtained varnish B was applied to the first resin layer side of the resin-coated copper foil obtained by the above method using a bar coater to obtain a coating film. The coating film was then heated and dried at 150°C for 10 minutes to obtain a substrate (resin sheet) with an insulating resin layer having a first resin layer and a second resin layer in this order from the substrate side. The thickness of the first resin layer was 2.5 μm, and the thickness of the second resin layer was 23.2 μm.

[0160] [Example 11] 60 parts by weight of block copolymer polyimide (product name: YN-003N, manufactured by PI Technical Research Institute), 40 parts by weight of 2,2-bis-{4-(4-maleimidophenoxy)phenyl}propane (product name: BMI-80, manufactured by K.I. Chemical Co., Ltd.), 60 parts by weight of spherical silica (product name: SO-C1, average particle size 0.3 μm, manufactured by Admatechs Co., Ltd.), and 0.2 parts by weight of a wetting and dispersing agent (product name: BYK-W903, manufactured by BYK Japan Co., Ltd.) were mixed and then diluted with NMP to obtain a resin composition solution, Varnish A. The resulting Varnish A was applied to the matte side of 12 μm-thick copper foil (product name: 3EC-M2S-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) using a bar coater to obtain a coating film. The coating film was then dried by heating at 180° C. for 10 minutes to obtain a resin-coated copper foil having a first resin layer formed on the copper foil.

[0161] Next, 36 parts by mass of biphenylaralkyl phenolic resin (product name: KAYAHARD GPH-103, hydroxyl equivalent: 231 g / eq., manufactured by Nippon Kayaku Co., Ltd.), 39 parts by mass of biphenylaralkyl epoxy resin (product name: NC-3000-FH, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 320 g / eq.), 7 parts by mass of naphthalenearalkyl epoxy resin (product name: HP-9900, epoxy equivalent: 274 g / eq., manufactured by DIC Corporation), 18 parts by mass of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane (product name: BMI-70, manufactured by K.I. Kasei Co., Ltd.), and 0.5 parts by mass of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) were blended and mixed, and then diluted with methyl ethyl ketone to obtain varnish B, a solution of the resin composition. The obtained varnish B was applied to the first resin layer side of the resin-coated copper foil obtained by the above method using a bar coater to obtain a coating film. The coating film was then heated and dried at 150°C for 10 minutes to obtain a substrate (resin sheet) with an insulating resin layer having a first resin layer and a second resin layer in this order from the substrate side. The thickness of the first resin layer was 2.5 μm, and the thickness of the second resin layer was 17.9 μm.

[0162] [Example 12] 60 parts by weight of block copolymer polyimide (product name: YN-003N, manufactured by PI Technical Research Institute), 40 parts by weight of 2,2-bis-{4-(4-maleimidophenoxy)phenyl}propane (product name: BMI-80, manufactured by K.I. Chemical Co., Ltd.), 60 parts by weight of spherical silica (product name: SO-C1, average particle size 0.3 μm, manufactured by Admatechs Co., Ltd.), and 0.2 parts by weight of a wetting and dispersing agent (product name: BYK-W903, manufactured by BYK Japan Co., Ltd.) were mixed and then diluted with NMP to obtain a resin composition solution, Varnish A. The resulting Varnish A was applied to the matte side of 12 μm-thick copper foil (product name: 3EC-M2S-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) using a bar coater to obtain a coating film. The coating film was then dried by heating at 180° C. for 10 minutes to obtain a resin-coated copper foil having a first resin layer formed on the copper foil.

[0163] Next, 36 parts by mass of biphenylaralkyl phenolic resin (product name: KAYAHARD GPH-103, hydroxyl equivalent: 231 g / eq., manufactured by Nippon Kayaku Co., Ltd.), 39 parts by mass of biphenylaralkyl epoxy resin (product name: NC-3000-FH, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 320 g / eq.), 7 parts by mass of naphthalenearalkyl epoxy resin (product name: HP-9900, epoxy equivalent: 274 g / eq., manufactured by DIC Corporation), 18 parts by mass of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane (product name: BMI-70, manufactured by K.I. Kasei Co., Ltd.), and 0.5 parts by mass of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) were blended and mixed, and then diluted with methyl ethyl ketone to obtain varnish B, a solution of the resin composition. The obtained varnish B was applied to the first resin layer side of the resin-coated copper foil obtained by the above method using a bar coater to obtain a coating film. The coating film was then heated and dried at 150°C for 10 minutes to obtain a substrate (resin sheet) with an insulating resin layer having a first resin layer and a second resin layer in this order from the substrate side. The thickness of the first resin layer was 2.5 μm, and the thickness of the second resin layer was 14.3 μm.

[0164] [Example 13] 60 parts by weight of block copolymer polyimide (product name: YN-003N, manufactured by PI Technical Research Institute), 40 parts by weight of 2,2-bis-{4-(4-maleimidophenoxy)phenyl}propane (product name: BMI-80, manufactured by K.I. Chemical Co., Ltd.), 60 parts by weight of spherical silica (product name: SO-C1, average particle size 0.3 μm, manufactured by Admatechs Co., Ltd.), and 0.2 parts by weight of a wetting and dispersing agent (product name: BYK-W903, manufactured by BYK Japan Co., Ltd.) were mixed and then diluted with NMP to obtain a resin composition solution, Varnish A. The resulting Varnish A was applied to the matte side of 12 μm-thick copper foil (product name: 3EC-M2S-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) using a bar coater to obtain a coating film. The coating film was then dried by heating at 180° C. for 10 minutes to obtain a resin-coated copper foil having a first resin layer formed on the copper foil.

[0165] Next, 36 parts by mass of biphenylaralkyl phenolic resin (product name: KAYAHARD GPH-103, hydroxyl equivalent: 231 g / eq., manufactured by Nippon Kayaku Co., Ltd.), 39 parts by mass of biphenylaralkyl epoxy resin (product name: NC-3000-FH, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 320 g / eq.), 7 parts by mass of naphthalenearalkyl epoxy resin (product name: HP-9900, epoxy equivalent: 274 g / eq., manufactured by DIC Corporation), 18 parts by mass of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane (product name: BMI-70, manufactured by K.I. Kasei Co., Ltd.), and 0.5 parts by mass of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) were blended and mixed, and then diluted with methyl ethyl ketone to obtain varnish B, a solution of the resin composition. The obtained varnish B was applied to the first resin layer side of the resin-coated copper foil obtained by the above method using a bar coater to obtain a coating film. The coating film was then heated and dried at 150°C for 10 minutes to obtain a substrate (resin sheet) with an insulating resin layer having a first resin layer and a second resin layer in this order from the substrate side. The thickness of the first resin layer was 2.5 μm, and the thickness of the second resin layer was 4.5 μm.

[0166] [Comparative Example 1] 36 parts by mass of biphenylaralkyl phenolic resin (product name: KAYAHARD GPH-103, hydroxyl equivalent: 231 g / eq., manufactured by Nippon Kayaku Co., Ltd.), 39 parts by mass of biphenylaralkyl epoxy resin (product name: NC-3000-FH, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 320 g / eq.), 7 parts by mass of naphthalenearalkyl epoxy resin (product name: HP-9900, epoxy equivalent: 274 g / eq., manufactured by DIC Corporation), 18 parts by mass of bis(3-ethyl-5-methyl-4-maleimidodiphenyl)methane (product name: BMI-70, manufactured by K.I. Kasei Co., Ltd.), and 0.5 parts by mass of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) were blended and mixed, and then diluted with methyl ethyl ketone to obtain varnish A, a solution of the resin composition. The obtained varnish A was applied to the matte side of a 12 μm thick copper foil (product name: 3EC-M2S-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) using a bar coater to obtain a coating film. The coating film was then dried by heating at 150° C. for 10 minutes to obtain a resin-coated copper foil having a first resin layer formed on the copper foil.

[0167] Biphenyl aralkyl phenolic resin (product name: KAYAHARD GPH-103, hydroxyl equivalent: 231 g / eq., manufactured by Nippon Kayaku Co., Ltd.) 36 parts by mass, biphenyl aralkyl epoxy resin (product name: NC-3000-FH, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 320 g / eq.) 39 parts by mass, naphthalene aralkyl epoxy resin (product name: HP-9900, epoxy equivalent: 274 g / eq., manufactured by DIC Corporation) 7 parts by mass, bis(3-ethyl-5-methyl-4-maleimidodiphenyl)methane (product name: BMI-70, manufactured by K.I. Kasei Co., Ltd.) 18 parts by mass, slurry silica (product name: SC2050-MB, average particle size 0.7 μm, manufactured by Admatechs Co., Ltd.) 300 parts by mass, styrene butadiene rubber (product name: JSR 20 parts by weight of a wetting and dispersing agent 1 (product name: DISPERBYK-161, manufactured by BYK Japan Co., Ltd.), 2 parts by weight of a wetting and dispersing agent 2 (product name: DISPERBYK-111, manufactured by BYK Japan Co., Ltd.), 1 part by weight of a silane coupling agent (product name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.), and 0.5 parts by weight of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) were blended and mixed, and then diluted with methyl ethyl ketone to obtain a resin composition, Varnish B. The resulting Varnish B was applied to the first resin layer side of the resin-coated copper foil obtained by the above method using a bar coater to obtain a coating film. The coating film was then heated and dried at 150°C for 10 minutes to obtain a substrate (resin sheet) with an insulating resin layer, having a first resin layer and a second resin layer in that order from the substrate side. The first resin layer had a thickness of about 2.0 μm, and the second resin layer had a thickness of 5.1 μm.

[0168] Comparative Example 2 36 parts by mass of biphenylaralkyl phenolic resin (product name: KAYAHARD GPH-103, hydroxyl group equivalent: 231 g / eq., manufactured by Nippon Kayaku Co., Ltd.), 39 parts by mass of biphenylaralkyl epoxy resin (product name: NC-3000-FH, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 320 g / eq.), 7 parts by mass of naphthalenearalkyl epoxy resin (product name: HP-9900, epoxy equivalent: 274 g / eq., manufactured by DIC Corporation), 18 parts by mass of bis(3-ethyl-5-methyl-4-maleimidodiphenyl)methane (product name: BMI-70, manufactured by K.I. Kasei Co., Ltd.), and 0.5 parts by mass of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) were blended and mixed, and then diluted with methyl ethyl ketone to obtain varnish A, a solution of the resin composition. The obtained varnish A was applied to the matte side of a 12 μm thick copper foil (product name: 3EC-M2S-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) using a bar coater to obtain a coating film. The coating film was then dried by heating at 150° C. for 10 minutes to obtain a resin-coated copper foil having a first resin layer formed on the copper foil.

[0169] Next, 36 parts by mass of biphenyl aralkyl phenol resin (product name: KAYAHARD GPH-103, hydroxyl group equivalent: 231 g / eq., manufactured by Nippon Kayaku Co., Ltd.), 39 parts by mass of biphenyl aralkyl epoxy resin (product name: NC-3000-FH, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 320 g / eq.), 7 parts by mass of naphthalene aralkyl epoxy resin (product name: HP-9900, epoxy equivalent: 274 g / eq., manufactured by DIC Corporation), 18 parts by mass of bis(3-ethyl-5-methyl-4-maleimidodiphenyl)methane (product name: BMI-70, manufactured by K.I. Kasei Co., Ltd.), 420 parts by mass of slurry silica (product name: SC2050-MB, average particle size: 0.7 μm, manufactured by Admatechs Co., Ltd.), and styrene butadiene rubber (product name: JSR 40 parts by weight of a wetting and dispersing agent (TR2003, manufactured by JSR Corporation), 1 part by weight of a wetting and dispersing agent 1 (product name: DISPERBYK-161, manufactured by BYK Japan), 2 parts by weight of a wetting and dispersing agent 2 (product name: DISPERBYK-111, manufactured by BYK Japan), 1 part by weight of a silane coupling agent (product name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.), and 0.5 parts by weight of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) were blended and mixed, and then diluted with methyl ethyl ketone to obtain a resin composition solution, Varnish B. The resulting Varnish B was applied to the first resin layer side of the resin-coated copper foil obtained by the above method using a bar coater to obtain a coating film. The coating film was then heated and dried at 150°C for 10 minutes to obtain a substrate (resin sheet) with an insulating resin layer, having a first resin layer and a second resin layer in that order from the substrate side. The first resin layer had a thickness of 2.0 μm, and the second resin layer had a thickness of 4.3 μm.

[0170] Comparative Example 3 60 parts by weight of block copolymer polyimide (product name: YN-003N, manufactured by PI Technical Research Institute) and 40 parts by weight of 2,2-bis-{4-(4-maleimidophenoxy)phenyl}propane (product name: BMI-80, manufactured by K.I. Chemical Co., Ltd.) were blended and mixed, then diluted with NMP to obtain a resin composition solution, Varnish A. The resulting Varnish A was applied to the matte side of 12 μm-thick copper foil (product name: 3EC-M2S-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) using a bar coater to obtain a coating film. The coating film was then heated and dried at 180°C for 10 minutes to obtain a resin-coated copper foil with a first resin layer formed on the copper foil.

[0171] Next, 36 parts by mass of biphenyl aralkyl phenol resin (product name: KAYAHARD GPH-103, hydroxyl group equivalent: 231 g / eq., manufactured by Nippon Kayaku Co., Ltd.), 39 parts by mass of biphenyl aralkyl epoxy resin (product name: NC-3000-FH, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 320 g / eq.), 7 parts by mass of naphthalene aralkyl epoxy resin (product name: HP-9900, epoxy equivalent: 274 g / eq., manufactured by DIC Corporation), 18 parts by mass of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane (product name: BMI-70, manufactured by K.I. Kasei Co., Ltd.), 300 parts by mass of slurry silica (product name: SC2050-MB, average particle size 0.7 μm, manufactured by Admatechs Co., Ltd.), and styrene butadiene rubber (product name: JSR 20 parts by weight of a wetting and dispersing agent (TR2003, manufactured by JSR Corporation), 1 part by weight of a wetting and dispersing agent 1 (product name: DISPERBYK-161, manufactured by BYK Japan), 2 parts by weight of a wetting and dispersing agent 2 (product name: DISPERBYK-111, manufactured by BYK Japan), 1 part by weight of a silane coupling agent (product name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.), and 0.5 parts by weight of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) were blended and mixed, and then diluted with methyl ethyl ketone to obtain a resin composition solution, Varnish B. The resulting Varnish B (resin composition) was applied to the first resin layer side of the resin-coated copper foil obtained by the above method using a bar coater to obtain a coating film. The coating film was then heated and dried at 150°C for 10 minutes to obtain a substrate (resin sheet) with an insulating resin layer, having a first resin layer and a second resin layer in that order from the substrate side. The first resin layer had a thickness of 2.5 μm, and the second resin layer had a thickness of 5.1 μm.

[0172] Comparative Example 4 30 parts by weight of block copolymer polyimide (product name: YN-003N, manufactured by PI Technical Research Institute) and 60 parts by weight of 2,2-bis-{4-(4-maleimidophenoxy)phenyl}propane (product name: BMI-80, manufactured by K.I. Chemical Co., Ltd.) were blended and mixed, then diluted with NMP to obtain a resin composition solution, Varnish A. The resulting Varnish A was applied to the matte side of 12 μm-thick copper foil (product name: 3EC-M2S-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) using a bar coater to obtain a coating film. The coating film was then heated and dried at 180°C for 10 minutes to obtain a resin-coated copper foil with a first resin layer formed on the copper foil.

[0173] Next, 36 parts by mass of biphenyl aralkyl phenol resin (product name: KAYAHARD GPH-103, hydroxyl group equivalent: 231 g / eq., manufactured by Nippon Kayaku Co., Ltd.), 39 parts by mass of biphenyl aralkyl epoxy resin (product name: NC-3000-FH, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 320 g / eq.), 7 parts by mass of naphthalene aralkyl epoxy resin (product name: HP-9900, epoxy equivalent: 274 g / eq., manufactured by DIC Corporation), 18 parts by mass of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane (product name: BMI-70, manufactured by K.I. Kasei Co., Ltd.), 300 parts by mass of slurry silica (product name: SC2050-MB, average particle size 0.7 μm, manufactured by Admatechs Co., Ltd.), and styrene butadiene rubber (product name: JSR 20 parts by weight of a wetting and dispersing agent (TR2003, manufactured by JSR Corporation), 1 part by weight of a wetting and dispersing agent 1 (product name: DISPERBYK-161, manufactured by BYK Japan), 2 parts by weight of a wetting and dispersing agent 2 (product name: DISPERBYK-111, manufactured by BYK Japan), 1 part by weight of a silane coupling agent (product name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.), and 0.5 parts by weight of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) were blended and mixed, and then diluted with methyl ethyl ketone to obtain a resin composition solution, Varnish B. The resulting Varnish B (resin composition) was applied to the first resin layer side of the resin-coated copper foil obtained by the above method using a bar coater to obtain a coating film. The coating film was then heated and dried at 150°C for 10 minutes to obtain a substrate (resin sheet) with an insulating resin layer, having a first resin layer and a second resin layer in that order from the substrate side. The first resin layer had a thickness of 4 μm, and the second resin layer had a thickness of 5.1 μm.

[0174] <Characteristics> The properties of the substrate with an insulating resin layer were measured by the following methods.

[0175] [Fabrication of inner layer circuit board] The copper foil surfaces on both sides of a glass cloth-based BT resin double-sided copper-clad laminate (copper foil thickness 12 μm, thickness 0.2 mm, manufactured by Mitsubishi Gas Chemical Company, Inc., product name: CCL-HL832NS) with an inner layer circuit having a copper residual ratio of 60% were roughened using a pretreatment liquid (manufactured by MEC Co., Ltd., product name: CZ8100) to obtain an inner layer circuit board.

[0176] [Production of metal foil-clad laminates] The two substrates with insulating resin layers were arranged with the second resin layer surface facing the inner layer circuit board, sandwiching the inner layer circuit board, and then laminate molding was performed at a pressure of 3.0 MPa and a temperature of 220°C for 60 minutes to obtain a copper-clad laminate.

[0177] [Measurement of thickness loss (TΔ)] The copper-clad laminate obtained as described above was polished parallel to the lamination direction to expose the cross section, thereby obtaining a sample. The thickness of the first resin layer of the obtained sample was measured using a scanning electron microscope (SEM) and compared with the thickness of the first resin layer in the insulating resin layer-attached substrate to evaluate the thickness reduction. The thickness reduction (TΔ) of the first resin layer was calculated as described above from the thickness of the first resin layer in the insulating resin layer-attached substrate and the thickness of the first resin layer in the copper-clad laminate. The thickness reduction of the second resin layer was also calculated as described above.

[0178] [Formability (embedding) of printed wiring boards] The copper foil on both sides of the copper-clad laminate was removed by etching to obtain a sample. The surface of the obtained sample was visually inspected to determine whether or not there were voids. Here, voids refer to areas with open spaces and no resin present. If many voids were observed, specifically if the void area occupied an average of 30% or more of the resin in the observation area, the sample was deemed unmoldable and rated "C." If voids were observed but only in small numbers, specifically if the void area occupied an average of less than 30% of the resin in the observation area, the sample was deemed moldable and rated "B." If no voids were observed, the sample was deemed well moldable and rated "A." The results are shown in Table 1.

[0179] <Minimum melt viscosity of resin sheet> The minimum melt viscosity of the second resin layer in the substrate with an insulating resin layer obtained as described above was measured using a rheometer (manufactured by TA Instruments Japan) under the following conditions: starting temperature 80°C, ending temperature 180°C, heating rate 3°C / min, frequency 10 pts / s, and strain 0.1%. The lower this minimum melt viscosity, the better the flow characteristics (resin flowability) during laminate production and the more excellent the moldability. The results of the minimum melt viscosity of the second resin layer are shown in Table 1.

[0180] <Insulation reliability evaluation> (Preparation of inner layer circuit board for insulation reliability evaluation) An inner layer circuit for evaluating insulation reliability was formed by a subtractive method on a glass cloth-based BT resin double-sided copper-clad laminate (copper foil thickness 12 μm, thickness 0.2 mm, manufactured by Mitsubishi Gas Chemical Company, Inc., product name: CCL-HL832NS). The copper foil surfaces on both sides of the laminate were roughened with a pretreatment solution (manufactured by MEC Co., Ltd., product name: CZ8101), to obtain an inner layer circuit board for evaluating insulation reliability.

[0181] (Preparation of substrate for evaluation of insulation reliability) The substrate with an insulating resin layer was placed with the surface of its second resin layer facing the inner layer circuit board for insulation reliability evaluation, so that the inner layer circuit board was sandwiched between them, and then laminate molding was performed at a pressure of 3.0 MPa and a temperature of 220°C for 120 minutes to obtain a copper-clad laminate with an insulating layer thickness of 5 μm. An outer layer circuit for insulation reliability evaluation was fabricated from the copper-clad laminate by a subtractive method to obtain a substrate for insulation reliability evaluation.

[0182] -Insulation reliability evaluation method- The above-mentioned insulation reliability evaluation substrate was subjected to moisture absorption treatment under conditions of 85°C and 60% RH for 168 hours, and then reflow treatment was performed three times at 260°C. After the reflow treatment, the resistance of the insulation reliability evaluation substrate was measured under HAST conditions (130°C, 85% RH, 5.0 V) for 96 hours, and the final resistance value was calculated and evaluated according to the following criteria, together with visual inspection during the measurement. <Standards> "A": No short circuit during measurement, final resistance is 1.0 x 10 8 It is greater than or equal to Ω. "B": No short circuit during measurement, final resistance is 1.0 x 10 8 It is less than Ω. "C": There is a short circuit during measurement. The results are shown in Table 1.

[0183] [Table 1]

[0184] As shown in Table 1, in the examples, the insulation reliability and embeddability were all excellent, with a grade of B or higher. On the other hand, in the comparative examples in which the thickness reduction of the first resin layer exceeded 30%, the insulation reliability was low, with a grade of C. Furthermore, in comparative example 2 in which the minimum melt viscosity of the second resin layer was 150,000 Pa·s, the embeddability was poor, with a grade of C. Industrial Applicability

[0185] According to the present invention, it is possible to provide a substrate with an insulating resin layer that is useful for printed wiring boards or substrates for mounting semiconductor elements, as well as a laminate and a method for producing a laminate using the same, and the present invention has industrial applicability in these fields. [Explanation of symbols]

[0186] 10...substrate with resin layer, 12...substrate, 14...first resin layer, 16...second resin layer, 20...inner layer circuit board, 22...substrate, 24...conductor layer, 30...laminated body, 100...multilayer coreless substrate, 111, 112...insulating layer, 113...conductor layer.

Claims

1. A substrate; a first resin layer provided on the substrate, the first resin layer having a thickness reduction of less than 30% when molded for 60 minutes under conditions of 220°C and a pressure of 3.0 MPa; a second resin layer provided on the first resin layer; Equipped with The substrate with an insulating resin layer, wherein the first resin layer contains polyimide, a bismaleimide compound, and 50 to 500 parts by mass of spherical silica per 100 parts by mass of resin solids.

2. 2. The substrate with an insulating resin layer according to claim 1, wherein the second resin layer has a minimum melt viscosity of 100,000 Pa·s or less.

3. The substrate with an insulating resin layer according to claim 1 or 2, wherein the first resin layer has a thickness of less than 10 μm.

4. The substrate with an insulating resin layer according to any one of claims 1 to 3, wherein the second resin layer has a thickness of 2.0 µm or more.

5. 5. The substrate with an insulating resin layer according to claim 1, wherein a total thickness of the first resin layer and the second resin layer is 3 μm or more and 20 μm or less.

6. The substrate with an insulating resin layer according to any one of claims 1 to 5, wherein the first resin layer contains at least one selected from the group consisting of liquid crystal polyester, epoxy resin, cyanate ester compound, phenolic resin, thermosetting modified polyphenylene ether resin, benzoxazine compound, organic group-modified silicone compound, and compound having a polymerizable unsaturated group.

7. The substrate with an insulating resin layer according to any one of claims 1 to 6, wherein the second resin layer contains at least one selected from the group consisting of an epoxy resin, a cyanate ester compound, a maleimide compound, a phenolic resin, a thermosetting modified polyphenylene ether resin, a benzoxazine compound, an organic group-modified silicone compound, and a compound having a polymerizable unsaturated group.

8. The substrate with an insulating resin layer according to any one of claims 1 to 7, which is used for producing a coreless substrate to be provided in a printed wiring board or a substrate for mounting a semiconductor element.

9. The substrate with an insulating resin layer according to claim 8 , wherein the coreless substrate is a three-layer coreless substrate.

10. A laminate having a build-up layer in which a conductor layer and an insulating layer formed using the substrate with an insulating resin layer according to any one of claims 1 to 9 are laminated.

11. The laminate according to claim 10, wherein at least one of the insulating layers has a thickness of 1 μm or more and less than 15 μm.

12. The laminate according to claim 10 or 11, wherein the build-up layer has a plurality of the conductor layers and the insulating layers, and the conductor layers are arranged between each of the insulating layers and on the surface of the outermost layer of the build-up layer.

13. The laminate according to any one of claims 10 to 12, wherein the conductor layers and the insulating layers are alternately stacked in the build-up layer, and the build-up layer has three or four insulating layers.

14. The laminate according to any one of claims 10 to 13, which is a coreless substrate.

15. A method for producing a laminate, comprising a step of forming an insulating layer on a surface of a conductor layer using the substrate with an insulating resin layer according to any one of claims 1 to 9, thereby forming a build-up layer in which the conductor layer and the insulating layer are laminated.

16. The method for producing a laminate according to claim 15, wherein at least one of the insulating layers has a thickness of 1 μm or more and less than 15 μm.

17. 17. The method for manufacturing a laminate according to claim 15 or 16, wherein the buildup layer has a plurality of the conductor layers and the insulating layers, and the conductor layers are arranged between each of the insulating layers and on the surface of the outermost layer of the buildup layer.

18. The method for producing a laminate according to any one of claims 15 to 17, wherein the insulating layers are three or four.

19. The method for producing a laminate according to any one of claims 15 to 18, wherein the laminate is a coreless substrate.

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