JP2023136756A - Method for manufacturing printed wiring board - Google Patents

Abstract

To provide a method for manufacturing a printed wiring board which can manufacture a printed wiring board while suppressing peeling failures between an insulation layer and a support.SOLUTION: A method for manufacturing a printed wiring board includes (I) a step of layering a resin sheet having a support having a release layer and a resin composition layer formed on the release layer of the support on an inner layer substrate so that the resin composition layer is joined to the inner layer substrate, (II) a step of thermosetting the resin composition layer under a nitrogen atmosphere, and (III) a step of peeling the support, in this order, wherein the release layer contains a (meth)acrylic resin, the resin composition layer contains a resin composition containing an imidazole-based compound, and thermosetting of the resin composition layer includes subjecting the resin composition layer to heating treatment of holding it at a temperature T1, and subjecting the resin composition layer to heating treatment of holding it at a temperature T2 higher than the temperature T1, in this order.SELECTED DRAWING: None

Description

The present invention relates to a method for manufacturing a printed wiring board.

Printed wiring boards are widely used in various electronic devices. Printed wiring boards are required to have finer circuit wiring and higher density in order to make electronic devices smaller and more functional. Here, as a method for manufacturing a printed wiring board, a manufacturing method using a build-up method in which insulating layers and conductive layers are alternately stacked on an inner layer substrate is known. The insulating layer is formed, for example, by forming a resin composition layer containing a resin composition on an inner layer substrate and thermally curing the resin composition layer (Patent Documents 1 and 2).

Japanese Patent Application Publication No. 2002-167427 JP2013-75948A

One method of forming an insulating layer of a printed wiring board is to use a resin sheet. In this method, a resin sheet including a support and a resin composition layer is prepared, an inner substrate and the resin composition layer are laminated, and the resin composition layer is further heat-cured to obtain an insulating layer. In this method, the resin composition layer is thermally cured while the resin composition layer and the support are in contact with each other, and the support is sometimes peeled off after the thermal curing. For example, in order to prevent damage to the insulating layer during the formation of via holes due to irradiation with laser light, after thermally curing the resin composition layer to form the insulating layer, and further forming via holes in the insulating layer, The support may peel off.

Further, thermosetting of the resin composition layer may be performed in a nitrogen atmosphere. For example, if the resin composition layer is thermally cured in an air atmosphere, the components contained in the resin composition layer may deteriorate due to oxidation. On the other hand, when the resin composition layer is thermally cured in a nitrogen atmosphere, the deterioration caused by oxidation can be suppressed, so that an insulating layer with excellent dielectric properties and mechanical properties can be formed.

However, when the resin composition layer is thermally cured in a nitrogen atmosphere without peeling off the support, poor peeling may occur between the support and the insulating layer obtained by curing the resin composition layer. . As a result of studies conducted by the present inventor, it was found that the above-mentioned peeling failure occurs when the resin composition layer contains an imidazole-based compound and the support is provided with a release layer containing a (meth)acrylic resin. .

The present invention was devised in view of the above problems, and an object of the present invention is to provide a method for manufacturing a printed wiring board that can manufacture the printed wiring board while suppressing peeling defects between the insulating layer and the support. shall be.

The inventors of the present invention have made extensive studies to solve the above problems. As a result, the present inventor discovered that the above-mentioned problem can be solved when the thermosetting of the resin composition layer includes curing the resin composition layer in stages by changing the curing temperature, and has developed the present invention. Completed.
That is, the present invention includes the following.

[1] (I) A resin sheet comprising a support provided with a release layer and a resin composition layer formed on the release layer of the support, such that the resin composition layer is bonded to the inner layer substrate. , a step of laminating the inner layer substrate;
(II) a step of thermosetting the resin composition layer in a nitrogen atmosphere; and (III) a step of peeling off the support;
A method for manufacturing a printed wiring board, the method comprising: in this order;
The release layer includes (meth)acrylic resin;
the resin composition layer includes a resin composition containing an imidazole compound;
Thermal curing of the resin composition layer includes, in this order, subjecting the resin composition layer to a heat treatment in which the resin composition layer is held at a temperature T1 and a heat treatment in which the resin composition layer is held at a temperature T2 higher than the temperature T1. A method for manufacturing printed wiring boards.
[2] The method for manufacturing a printed wiring board according to [1], wherein the resin composition contains a thermosetting resin.
[3] The thermosetting resin contains one or more selected from the group consisting of epoxy resin, phenol resin, active ester resin, carbodiimide resin, acid anhydride resin, amine resin, benzoxazine resin, cyanate ester resin, and thiol resin. The method for manufacturing a printed wiring board according to [2].
[4] The method for manufacturing a printed wiring board according to any one of [1] to [3], wherein the temperature T2 is 150° C. or higher.
[5] The method for manufacturing a printed wiring board according to any one of [1] to [4], wherein the difference T2-T1 between temperature T1 and temperature T2 is 20° C. or more.
[6] The method for manufacturing a printed wiring board according to any one of [1] to [5], wherein the temperature T1 is 50° C. or higher.
[7] The method of [1] to [6], wherein step (II) includes heating the resin composition layer to temperature T2 at a heating rate of 0.5° C./min or more and 30° C./min or less. A method for manufacturing a printed wiring board according to any one of the items.

According to the present invention, a printed wiring board can be manufactured while suppressing peeling defects between an insulating layer and a support.

Hereinafter, the present invention will be explained by showing embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and may be implemented with arbitrary changes within the scope of the claims and equivalents thereof.

In the following description, the term "long" refers to a film or sheet shape that is ten times longer than its width, unless otherwise specified. The length is preferably 20 times or more the width, and specifically may be long enough to be wound up into a roll for storage or transportation. The upper limit of the length is not particularly limited and may be, for example, 100,000 times the width or less.

[Overview of printed wiring board manufacturing method]
A method for manufacturing a printed wiring board according to an embodiment of the present invention uses a resin sheet including a support provided with a release layer and a resin composition layer formed on the release layer of the support. , manufactures printed wiring boards. Specifically, the method for manufacturing a printed wiring board according to this embodiment includes:
(I) a step of laminating the resin sheet on the inner layer substrate so that the resin composition layer is bonded to the inner layer substrate;
(II) a step of thermosetting the resin composition layer in a nitrogen atmosphere; and (III) a step of peeling off the support;
In this order. In this method, since the insulating layer is formed by curing the resin composition layer, a printed wiring board including the insulating layer can be manufactured.

The release layer included in the support contains (meth)acrylic resin. Moreover, the resin composition layer contains a resin composition containing an imidazole-based compound. Thermal curing of the resin composition layer in step (II) involves subjecting the resin composition layer to a heat treatment held at a temperature T1, and then a heat treatment held at a temperature T2 higher than the temperature T1. including attaching.

Conventionally, when a mold release layer containing a (meth)acrylic resin and a resin composition containing an imidazole compound were combined and further heat treated in a nitrogen atmosphere, poor peeling occurred between the insulating layer and the support. was occurring. Specifically, when an attempt was made to peel off the support, adhesion occurred between the insulating layer and the support, and the insulating layer or the support could be damaged. On the other hand, when the conditions for thermosetting in step (II) are controlled as in the present embodiment, poor peeling between the insulating layer and the support can be suppressed.

The present inventor conjectures the mechanism capable of suppressing peeling defects as described above as follows. However, the technical scope of the present invention is not limited to the mechanism described below.

If the resin composition layer is thermally cured in air, the catalytic activity of the imidazole compound is suppressed by oxygen and carbon dioxide contained in the air. However, when thermal curing is performed in a nitrogen atmosphere, the catalytic activity of the imidazole compound is not suppressed. Therefore, conventionally, due to the catalytic activity of the imidazole compound, a reaction occurs between the (meth)acrylic resin contained in the mold release layer and one or more components contained in the resin composition, and as a result, mold release It was possible for the layer and the resin composition layer to stick together. According to the inventor's study, the (meth)acrylic resin in the release layer reacts with thermosetting resins that may be included in the resin composition, and among them, it reacts significantly with epoxy resins, phenolic resins, and active ester resins. It is presumed that this is occurring. The present inventor conjectures that this adhesion was one of the causes of the conventional peeling failure.

On the other hand, in the method for manufacturing a printed wiring board according to the present embodiment, the resin composition is The material layer is cured in stages. In such stepwise curing, the reaction between the components contained in the resin composition layer is caused by the reaction between the (meth)acrylic resin contained in the release layer and the components contained in the resin composition. It takes priority over the reaction. For example, as a result of a reaction between components contained in the resin composition layer proceeding at temperature T1, the amount of reactive components in the resin composition layer decreases. Therefore, at the temperature T2, the degree of progress of the reaction between the (meth)acrylic resin contained in the release layer and the components contained in the resin composition layer is reduced. Therefore, it is possible to suppress adhesion between the mold release layer and the resin composition layer, thereby suppressing peeling defects.

[Resin sheet]
A resin sheet used in the method for manufacturing a printed wiring board according to an embodiment of the present invention includes a support provided with a release layer, and a resin composition layer provided on the release layer of the support.

-Support-
The support usually includes a support base material and a release layer on the support base material. Examples of the supporting base material include thermoplastic resin films, metal foils, and release paper, with thermoplastic resin films and metal foils being preferred.

When using a thermoplastic resin film as a supporting base material, examples of the thermoplastic resin include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polycarbonate (PC), and polymethyl methacrylate (PMMA). Examples include acrylic, cyclic polyolefin, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, and polyimide. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred, and inexpensive polyethylene terephthalate is particularly preferred.

When using metal foil as the supporting base material, examples of the metal foil include copper foil, aluminum foil, etc., and copper foil is preferable. As the copper foil, a foil made of a single metal such as copper may be used, or a foil made of an alloy of copper and other metals (for example, tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.) may be used. May be used.

The supporting base material may be subjected to surface treatment such as matte treatment, corona treatment, antistatic treatment, etc. on the surface on the side of the release layer.

The thickness of the supporting base material is not particularly limited, but is preferably in the range of 5 μm to 75 μm, more preferably in the range of 10 μm to 60 μm.

The release layer contains (meth)acrylic resin. In this specification, "(meth)acrylic resin" includes (meth)acrylic compounds and polymers thereof. Moreover, the "(meth)acrylic compound" includes an acrylic compound containing an acryloyl group, a methacryloyl compound containing a methacryloyl group, and a combination thereof.

Generally, the mold release layer is formed using a mold release agent. The mold release agent usually contains a mold release compound as a compound capable of imparting mold release properties, and may further contain any resin other than the mold release compound as necessary. Therefore, in one example, the mold release layer formed using a mold release agent contains a mold release compound, and may further contain any resin as necessary. In addition, in another example, a mold release layer formed using a mold release agent is formed by bonding some or all of the components contained in the mold release agent through a reaction such as a polymerization reaction and a crosslinking reaction. can be formed by curing. Therefore, in this example, the release layer may include the release compound and any resin contained in the release agent, and their reaction products (eg, polymers). The (meth)acrylic resin may be contained as a mold-releasing compound, as any resin, or as a reaction product thereof.

The mold release compound represents a compound that can exhibit the function of lowering the surface free energy of the mold release layer or reducing the static friction coefficient of the mold release layer. Therefore, the (meth)acrylic resin as the mold-releasing compound can be a (meth)acrylic resin that can exhibit the above-mentioned functions.

Examples of the (meth)acrylic resin as a mold release compound include (meth)acrylic resin containing a long-chain alkyl group, (meth)acrylic resin containing a fluorine atom, and the like.

The long-chain alkyl group refers to an alkyl group having usually 12 or more carbon atoms, preferably 16 or more carbon atoms. The (meth)acrylic resin containing such a long carbon chain in its molecule has high hydrophobicity, and therefore can exhibit high mold releasability. The upper limit of the number of carbon atoms in the long-chain alkyl group can be, for example, 25 or less. Examples of the (meth)acrylic resin containing a long-chain alkyl group include long-chain acrylic acrylates such as tetradecyl acrylate and octadecyl acrylate; long-chain acrylic methacrylates such as tetradecyl methacrylate and octadecyl methacrylate; and polymers thereof; Examples include.

Examples of (meth)acrylic resins containing fluorine atoms include fluoroalkyl acrylates such as trifluoroethyl acrylate; fluoroaryl acrylates such as pentafluorophenyl acrylate; fluoroalkyl methacrylates such as trifluoroethyl methacrylate; Examples include aryl methacrylate; and polymers thereof.

Examples of the (meth)acrylic resin as an arbitrary resin include acrylic acid, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-hexyl acrylate, lauryl acrylate, Acrylic compounds such as 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, hydroxypropyl acrylate, acrylamide, N-methylolacrylamide, diacetone acrylamide; methacrylic acid, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, methacrylic acid Examples include methacrylic compounds such as n-butyl, isobutyl methacrylate, n-hexyl methacrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, and hydroxypropyl methacrylate; and polymers thereof.

One type of (meth)acrylic resin may be used alone, or two or more types may be used in combination.

The amount of (meth)acrylic resin in the release layer is preferably 30% by mass or more, more preferably 50% by mass or more, still more preferably 70% by mass or more, particularly preferably It is 90% by mass or more, and usually 100% by mass or less. Conventionally, when a mold release layer containing a (meth)acrylic resin is employed in this way, there has been a problem of poor peeling between the insulating layer and the support. According to the manufacturing method described in this embodiment, this problem of peeling failure can be suppressed.

Further, the amount of (meth)acrylic resin in the mold release agent used for manufacturing the mold release layer is preferably 30% by mass or more, more preferably 50% by mass based on 100% by mass of the nonvolatile components of the mold release agent. % or more, more preferably 70% by mass or more, particularly preferably 90% by mass or more, and usually 100% by mass or less. Conventionally, when a mold release layer formed using a mold release agent containing a (meth)acrylic resin as described above is employed, there has been a problem of poor peeling between the insulating layer and the support. According to the manufacturing method described in this embodiment, this problem of peeling failure can be suppressed.

The release layer may further contain any component other than the (meth)acrylic resin in combination with the (meth)acrylic resin. Moreover, the mold release agent for forming the mold release layer may further contain any component other than the (meth)acrylic resin in combination with the (meth)acrylic resin. Examples of the optional component other than the (meth)acrylic resin include mold release compounds other than the (meth)acrylic resin. Examples of release compounds other than (meth)acrylic resins include long-chain alkyl group-containing resins, olefin resins, fluorine compounds, and wax compounds.

Examples of the long-chain alkyl group-containing compound include compounds other than (meth)acrylic resins containing a long-chain alkyl group. Specific examples of long-chain alkyl group-containing compounds include the "AsioResin" (registered trademark) series, which is a long-chain alkyl compound manufactured by Asio Sangyo Co., Ltd., and the "Piroyl" (registered trademark) series, which is a long-chain alkyl compound manufactured by Lion Specialty Chemicals. (registered trademark) series, and the "Rezem" series, which is an aqueous dispersion of long-chain alkyl compounds manufactured by Chukyo Yushi Co., Ltd.

Examples of olefin resins include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1 - Examples include dodecene.

Examples of the fluorine compound include compounds other than (meth)acrylic resins containing a fluorine atom in the molecule. Specific examples of fluorine compounds include perfluoroalkyl group-containing compounds, polymers of olefin compounds containing fluorine atoms, and aromatic fluorine compounds such as fluorobenzene.

Examples of wax-based compounds include natural waxes, synthetic waxes, and waxes that are a combination thereof. Natural waxes include vegetable waxes, animal waxes, mineral waxes, and petroleum waxes. Examples of vegetable waxes include candelilla wax, carnauba wax, rice wax, wood wax, and jojoba oil. Examples of animal waxes include beeswax, lanolin, and spermaceti. Examples of mineral waxes include montan wax, ozokerite, and ceresin. Examples of petroleum wax include paraffin wax, microcrystalline wax, and petrolatum. Examples of synthetic waxes include synthetic hydrocarbons, modified waxes, hydrogenated waxes, fatty acids, acid amides, amines, imides, esters, and ketones. Examples of synthetic hydrocarbons include Fischer-Tropsch wax (also known as sazowir wax) and polyethylene wax. Synthetic hydrocarbons include polypropylene, ethylene/acrylic acid copolymer, polyethylene glycol, polypropylene glycol, block combinations of polyethylene glycol and polypropylene glycol, and graft combinations of polyethylene glycol and polypropylene glycol. Among the polymers selected from the group, those having a low molecular weight (specifically, a viscosity average molecular weight of 500 or more and 20,000 or less) may be included. Examples of the modified wax include montan wax derivatives, paraffin wax derivatives, and microcrystalline wax derivatives. The derivative here refers to a compound obtained by any one of purification, oxidation, esterification, saponification, or a combination thereof. Hydrogenated waxes include, for example, hydrogenated castor oil and hydrogenated castor oil derivatives.

Any type of release compound other than the (meth)acrylic resin may be used alone or in combination of two or more types.

The amount of the mold release compound in the mold release agent (the total of the (meth)acrylic resin as the mold release compound and the mold release compounds other than the (meth)acrylic resin) is 100 mass of the nonvolatile components of the mold release agent. %, preferably 10% by mass or more, more preferably 15% by mass or more, particularly preferably 20% by mass or more, preferably 90% by mass or less, more preferably 60% by mass or less, particularly preferably 40% by mass. % or less.

In addition, the amount of the release compound ((meth)acrylic resin as a release compound and the total amount of release compounds other than the (meth)acrylic resin) in the release layer is 100% by mass of the release layer. , preferably 10% by mass or more, more preferably 15% by mass or more, particularly preferably 20% by mass or more, and preferably 90% by mass or less, more preferably 60% by mass or less, particularly preferably 40% by mass. It is as follows.

Another example of the optional component is any resin other than (meth)acrylic resin. Examples of arbitrary resins other than (meth)acrylic resins include epoxy resins, melamine resins, oxazoline compounds, carbodiimide compounds, polyester resins, and urethane resins. Any resin other than (meth)acrylic resin may be used alone or in combination of two or more.

The amount of any resin in the mold release agent (total of (meth)acrylic resin as any resin and any resin other than (meth)acrylic resin) is based on 100% by mass of nonvolatile components of the mold release agent. The content is preferably 10% by mass or more, more preferably 20% by mass or more, particularly preferably 40% by mass or more, and preferably 90% by mass or less, more preferably 80% by mass or less, particularly preferably 60% by mass or less. be.

In addition, the amount of any resin in the release layer (total of (meth)acrylic resin as any resin and any resin other than (meth)acrylic resin) is based on 100% by mass of the release layer. , preferably 10% by mass or more, more preferably 20% by mass or more, particularly preferably 40% by mass or more, preferably 90% by mass or less, more preferably 80% by mass or less, particularly preferably 60% by mass or less. .

Further examples of optional components include additives such as lubricants, inorganic particles, organic particles, surfactants, antioxidants, and thermal initiators. These additives may be used alone or in combination of two or more. The amount of the additive is not particularly limited, but may be, for example, 0.01% by mass or more and 10% by mass or less, based on 100% by mass in total of the mold release compound and any resin.

The thickness of the release layer is preferably 50 nm or more, more preferably 70 nm or more, and preferably 400 nm or less, more preferably 200 nm or less, particularly preferably 130 nm or less.

The support can be manufactured, for example, by a method that includes applying a release agent to the surface of the support substrate. The mold release agent may further contain a solvent in combination with non-volatile components such as the above-mentioned (meth)acrylic resin and optional components. When the mold release agent contains a solvent, the method for manufacturing the support preferably includes drying after applying the mold release agent.

As the solvent, an aqueous solvent is preferable from the viewpoint of suppressing rapid evaporation of the solvent and forming a uniform release layer. Examples of the aqueous solvent include water; a mixed solvent of water and a water-soluble organic solvent such as an alcohol solvent, a ketone solvent, and a glycol solvent; One type of solvent may be used alone, or two or more types may be used in combination. When a solvent is used, the nonvolatile component concentration of the mold release agent is preferably 40% by mass or less from the viewpoint of improving coating properties and forming a uniform mold release layer.

Examples of methods for applying the release agent include wire bar coating, reverse coating, gravure coating, die coating, blade coating, dip coating, air knife coating, curtain coating, and roller coating. It will be done.

The drying temperature of the mold release agent is not particularly limited. In one example, drying may be performed at a temperature range of 80° C. or higher and 130° C. or lower. In another example, drying may be performed at a temperature range of 160° C. or higher and 240° C. or lower.

A layer containing the non-volatile component of the mold release agent can be formed by applying the mold release agent to the surface of the supporting base material and drying as necessary. This layer may also be used as a release layer. Alternatively, the release layer may be obtained by subjecting the layer containing the nonvolatile component of the release agent to a curing treatment. Examples of the curing treatment include heat treatment and ultraviolet irradiation treatment. Usually, the above-mentioned curing treatment progresses reactions such as polymerization reaction and crosslinking reaction of some or all of the components contained in the mold release agent, and the mold release agent can be cured. It is possible to obtain a release layer consisting of a material.

Further, the method for manufacturing the support may include arbitrary treatments such as stretching treatment, if necessary.

-Resin composition layer-
The support includes a resin composition layer formed on the release layer of the support. Usually, the resin composition layer is in contact with the mold release layer of the support, and no other layer is provided between the mold release layer and the resin composition layer. This resin composition layer contains a resin composition, preferably only a resin composition.

The resin composition contains (A) an imidazole compound. (A) The imidazole compound usually functions as a curing catalyst in the resin composition. Specifically, the resin composition usually includes (B) a thermosetting resin, and the (A) imidazole compound can function as a catalyst that promotes the curing reaction of the (B) thermosetting resin.

(A) Imidazole compounds include, for example, 2-methylimidazole, 2-undecylimidazole, 2-heptadecyl imidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole , 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole , 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl -2-Phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-un Decylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4 -Diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2 -Phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methyl Examples include imidazole compounds such as imidazoline and 2-phenylimidazoline; and adducts of the imidazole compounds and epoxy resins.

(A) As the imidazole compound, a commercially available product may be used. (A) Commercially available imidazole compounds include, for example, "1B2PZ", "2E4MZ", "2MZA-PW", "2MZ-OK", "2MA-OK", and "2MA-OK" manufactured by Shikoku Kasei Kogyo Co., Ltd. -PW", "2PHZ", "2PHZ-PW", "Cl1Z", "Cl1Z-CN", "Cl1Z-CNS", "C11Z-A"; "P200-H50" manufactured by Mitsubishi Chemical Corporation, etc. . (A) The imidazole compounds may be used alone or in combination of two or more.

The amount of the imidazole compound (A) in the resin composition is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, particularly preferably The content is 0.03% by mass or more, preferably 1% by mass or less, more preferably 0.5% by mass or less, particularly preferably 0.1% by mass or less.

The amount of imidazole compound (A) in the resin composition is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, particularly preferably The content is 0.1% by mass or more, preferably 5% by mass or less, more preferably 2% by mass or less, particularly preferably 1% by mass or less. The resin component of the resin composition refers to the nonvolatile components of the resin composition excluding the inorganic filler (C) described below.

The resin composition usually contains (B) a thermosetting resin. (B) As the thermosetting resin, a resin that can cause a reaction and form a bond when heat is applied to cure the resin composition can be used. (B) Thermosetting resins include, for example, epoxy resins, phenol resins, active ester resins, carbodiimide resins, acid anhydride resins, amine resins, benzoxazine resins, cyanate resins, and thiol resins. (B) The thermoplastic resin may be used alone or in any combination of two or more.

The epoxy resin may be a resin having an epoxy group. Examples of the epoxy resin include bixylenol type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, Naphthol novolac type epoxy resin, phenol novolac type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, glycidylamine type epoxy resin, glycidyl ester type epoxy resin, cresol novolac type epoxy resin, phenol aralkyl type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin, epoxy resin with butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, spiro ring-containing epoxy resin, cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, naphthylene ether type epoxy resin, trimethylol type epoxy resin, tetraphenylethane type epoxy resin, isocyanurate type epoxy resin, phenolphthalimidine type epoxy resin and the like. One type of epoxy resin may be used alone, or two or more types may be used in combination.

The epoxy resin preferably contains an epoxy resin containing an aromatic structure from the viewpoint of obtaining an insulating layer with excellent heat resistance. The aromatic structure is a chemical structure that is generally defined as aromatic, and also includes polycyclic aromatics and aromatic heterocycles. Examples of the epoxy resin containing an aromatic structure include bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, bisphenol AF epoxy resin, dicyclopentadiene epoxy resin, trisphenol epoxy resin, Naphthol novolac type epoxy resin, phenol novolac type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, bishkylenol type epoxy resin, glycidylamine type epoxy resin with aromatic structure Resin, glycidyl ester type epoxy resin with aromatic structure, cresol novolak type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin with aromatic structure, epoxy resin with butadiene structure with aromatic structure, aromatic alicyclic epoxy resin, heterocyclic epoxy resin, spiro ring-containing epoxy resin with aromatic structure, cyclohexanedimethanol type epoxy resin with aromatic structure, naphthylene ether type epoxy resin, having aromatic structure Examples include trimethylol type epoxy resin, tetraphenylethane type epoxy resin having an aromatic structure, and the like.

It is preferable that the resin composition contains an epoxy resin having two or more epoxy groups in one molecule. The proportion of the epoxy resin having two or more epoxy groups in one molecule is preferably 50% by mass or more, more preferably 60% by mass or more, particularly preferably 70% by mass, based on 100% by mass of the nonvolatile components of the entire epoxy resin. % by mass or more.

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

As the liquid epoxy resin, a liquid epoxy resin having two or more epoxy groups in one molecule is preferable.

Liquid epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, phenol novolak type epoxy resin, and ester skeleton. Preferred are alicyclic epoxy resins, cyclohexane-type epoxy resins, cyclohexanedimethanol-type epoxy resins, and epoxy resins having a butadiene structure.

Specific examples of liquid epoxy resins include "HP4032", "HP4032D", "HP4032SS" (naphthalene type epoxy resin) manufactured by DIC; "828US", "828EL", "jER828EL", and "825" manufactured by Mitsubishi Chemical Corporation. ", "Epicote 828EL" (bisphenol A type epoxy resin); Mitsubishi Chemical's "jER807", "1750" (bisphenol F type epoxy resin); Mitsubishi Chemical's "jER152" (phenol novolac type epoxy resin); Mitsubishi Chemical's "630", "630LSD", "604" (glycidylamine type epoxy resin); ADEKA's "ED-523T" (glycyol type epoxy resin); ADEKA's "EP-3950L", "EP-3980S" (glycidylamine type epoxy resin); "EP-4088S" (dicyclopentadiene type epoxy resin) manufactured by ADEKA; "ZX1059" manufactured by Nippon Steel Chemical & Materials (bisphenol A type epoxy resin and bisphenol F-type epoxy resin mixture); “EX-721” manufactured by Nagase ChemteX (glycidyl ester type epoxy resin); “Celoxide 2021P” manufactured by Daicel (alicyclic epoxy resin having an ester skeleton); Daicel “PB-3600” manufactured by Nippon Soda Co., Ltd.; “JP-100” and “JP-200” manufactured by Nippon Soda Co., Ltd. (epoxy resins with a butadiene structure); “ZX1658” and “ZX1658GS” manufactured by Nippon Steel Chemical & Materials Co., Ltd. (liquid 1,4-glycidylcyclohexane type epoxy resin), "YX8000" manufactured by Mitsubishi Chemical Corporation (hydrogenated bisphenol A type epoxy resin), and the like. These may be used alone or in combination of two or more.

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

Solid epoxy resins include bixylenol type epoxy resin, naphthalene type epoxy resin, naphthalene type tetrafunctional epoxy resin, naphthol novolac type epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, Naphthol type epoxy resin, biphenyl type epoxy resin, naphthylene ether type epoxy resin, anthracene type epoxy resin, bisphenol A type epoxy resin, bisphenol AF type epoxy resin, phenol aralkyl type epoxy resin, tetraphenylethane type epoxy resin, phenolphthalyl Midine type epoxy resins are preferred.

Specific examples of solid epoxy resins include "HP4032H" (naphthalene type epoxy resin) manufactured by DIC; "HP-4700" and "HP-4710" (naphthalene type tetrafunctional epoxy resin) manufactured by DIC; “N-690” (cresol novolak type epoxy resin) manufactured by DIC; “N-695” (cresol novolac type epoxy resin) manufactured by DIC; “HP-7200”, “HP-7200HH”, “HP” manufactured by DIC -7200H", "HP-7200L" (dicyclopentadiene type epoxy resin); "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S" manufactured by DIC ", "HP6000" (naphthylene ether type epoxy resin); "EPPN-502H" manufactured by Nippon Kayaku Co., Ltd. (trisphenol type epoxy resin); "NC7000L" manufactured by Nippon Kayaku Co., Ltd. (naphthol novolac type epoxy resin); “NC3000H”, “NC3000”, “NC3000L”, “NC3000FH”, “NC3100” manufactured by Nippon Kayaku Co., Ltd. (biphenyl type epoxy resin); “ESN475V” and “ESN4100V” manufactured by Nippon Steel Chemical & Materials Co., Ltd. (naphthalene type) epoxy resin); “ESN485” (naphthol type epoxy resin) manufactured by Nippon Steel Chemical &Materials; “ESN375” (dihydroxynaphthalene type epoxy resin) manufactured by Nippon Steel Chemical &Materials; “YX4000H” manufactured by Mitsubishi Chemical; "YX4000", "YX4000HK", "YL7890" (bixylenol type epoxy resin); Mitsubishi Chemical's "YL6121" (biphenyl type epoxy resin); Mitsubishi Chemical's "YX8800" (anthracene type epoxy resin); Mitsubishi “YX7700” manufactured by Chemical Co., Ltd. (phenol aralkyl type epoxy resin); “PG-100” and “CG-500” manufactured by Osaka Gas Chemical Company; “YL7760” manufactured by Mitsubishi Chemical Company (bisphenol AF type epoxy resin); Mitsubishi "YL7800" (fluorene type epoxy resin) manufactured by Chemical Company; "jER1010" (bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical Company; "jER1031S" (tetraphenylethane type epoxy resin) manufactured by Mitsubishi Chemical Company; Nippon Kayaku Examples include "WHR991S" (phenolphthalimidine type epoxy resin) manufactured by Co., Ltd. These may be used alone or in combination of two or more.

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

The epoxy equivalent of the epoxy resin is preferably 50 g/eq. ～5,000g/eq. , more preferably 60g/eq. ～3,000g/eq. , more preferably 80g/eq. ~2,000g/eq. , particularly preferably 110 g/eq. ～1,000g/eq. It is. Epoxy equivalent represents the mass of resin per equivalent of epoxy group. This epoxy equivalent can be measured according to JIS K7236.

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

The amount of epoxy resin in the resin composition is preferably 1% by mass or more, more preferably 5% by mass or more, particularly preferably 10% by mass or more, based on 100% by mass of nonvolatile components in the resin composition. Preferably it is 50% by mass or less, more preferably 40% by mass or less, particularly preferably 30% by mass or less.

The amount of epoxy resin in the resin composition is preferably 10% by mass or more, more preferably 30% by mass or more, particularly preferably 50% by mass or more, based on 100% by mass of the resin component in the resin composition. It is preferably 90% by mass or less, more preferably 85% by mass or less, particularly preferably 80% by mass or less.

The phenol resin may be a resin having one or more, preferably two or more, hydroxyl groups in one molecule bonded to an aromatic ring such as a benzene ring or a naphthalene ring. From the viewpoint of heat resistance and water resistance, phenolic resins having a novolak structure are preferred. Furthermore, from the viewpoint of adhesion, nitrogen-containing phenolic resins are preferred, and triazine skeleton-containing phenolic resins are more preferred. Among these, triazine skeleton-containing phenol novolac resins are preferred from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion.

Specific examples of phenolic resins include "MEH-7700", "MEH-7810", and "MEH-7851" manufactured by Meiwa Kasei Co., Ltd., and "NHN", "CBN", and "GPH" manufactured by Nippon Kayaku Co., Ltd. , "SN-170", "SN-180", "SN-190", "SN-475", "SN-485", "SN-495", "SN-375" manufactured by Nippon Steel Chemical & Materials. , "SN-395", DIC's "LA-7052", "LA-7054", "LA-3018", "LA-3018-50P", "LA-1356", "TD2090", "TD- 2090-60M" etc. One type of phenol resin may be used alone, or two or more types may be used in combination.

The amount of phenolic resin in the resin composition is preferably 0.1% by mass or more, preferably 0.5% by mass or more, particularly preferably 1% by mass or more, based on 100% by mass of nonvolatile components in the resin composition. The content is preferably 50% by mass or less, more preferably 40% by mass or less, particularly preferably 30% by mass or less.

The amount of phenolic resin in the resin composition is preferably 0.1% by mass or more, preferably 1% by mass or more, particularly preferably 3% by mass or more, based on 100% by mass of the resin component in the resin composition. , preferably 60% by mass or less, more preferably 50% by mass or less, particularly preferably 40% by mass or less.

The active ester resin may be a resin having one or more active ester groups in one molecule. The active ester group can be an ester linkage directly attached to the aromatic ring. Active ester resins generally include compounds having two or more active ester groups with high reaction activity in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds. is preferred. The active ester resin is preferably one obtained by a condensation reaction between a carboxylic acid compound and/or a thiocarboxylic acid compound and a hydroxy compound and/or a thiol compound. Particularly from the viewpoint of improving heat resistance, active ester resins obtained from a carboxylic acid compound and a hydroxy compound are preferred, and active ester resins obtained from a carboxylic acid compound and a phenol compound and/or a naphthol compound are more preferred. Examples of the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of phenolic compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalin, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m- Cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, Examples include benzenetriol, dicyclopentadiene type diphenol compounds, and phenol novolacs. Here, the term "dicyclopentadiene type diphenol compound" refers to a diphenol compound obtained by condensing two molecules of phenol with one molecule of dicyclopentadiene.

Specifically, the active ester resin includes dicyclopentadiene type active ester resin, naphthalene type active ester resin containing a naphthalene structure, active ester resin containing an acetylated product of phenol novolac, and active ester resin containing a benzoylated product of phenol novolac. is preferred, and more preferably at least one selected from dicyclopentadiene type active ester resins and naphthalene type active ester resins. As the dicyclopentadiene type active ester resin, an active ester resin containing a dicyclopentadiene type diphenol structure is preferable.

Commercially available active ester resins include, for example, "EXB9451", "EXB9460", "EXB9460S", "EXB-8000L", and "EXB-8000L-65M" as active ester resins containing a dicyclopentadiene type diphenol structure. , "EXB-8000L-65TM", "HPC-8000L-65TM", "HPC-8000", "HPC-8000-65T", "HPC-8000H", "HPC-8000H-65TM" (manufactured by DIC); Active ester resins containing a naphthalene structure include "HP-B-8151-62T", "EXB-8100L-65T", "EXB-8150-60T", "EXB-8150-62T", "EXB-9416-70BK", "HPC-8150-60T", "HPC-8150-62T", "EXB-8" (manufactured by DIC); As a phosphorus-containing active ester resin, "EXB9401" (manufactured by DIC); an acetylated product of phenol novolak "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester resin; "YLH1026", "YLH1030", "YLH1048" (manufactured by Mitsubishi Chemical Corporation) as active ester resins that are benzoylated products of phenol novolak; Contains styryl group and naphthalene structure Examples of the active ester resin include "PC1300-02-65MA" (manufactured by Air Water). One type of active ester resin may be used alone, or two or more types may be used in combination.

The amount of active ester resin in the resin composition is preferably 0.1% by mass or more, preferably 0.5% by mass or more, particularly preferably 1% by mass, based on 100% by mass of nonvolatile components in the resin composition. The content is preferably 50% by mass or less, more preferably 40% by mass or less, particularly preferably 30% by mass or less.

The amount of active ester resin in the resin composition is preferably 0.1% by mass or more, preferably 1% by mass or more, particularly preferably 3% by mass or more, based on 100% by mass of the resin component in the resin composition. The content is preferably 60% by mass or less, more preferably 50% by mass or less, particularly preferably 40% by mass or less.

The carbodiimide resin may be a resin having one or more, preferably two or more, carbodiimide structures in one molecule. Examples of the carbodiimide resin include biscarbodiimide, polycarbodiimide, and the like. Specific examples of biscarbodiimides include aliphatic biscarbodiimides such as tetramethylene-bis(t-butylcarbodiimide) and cyclohexanebis(methylene-t-butylcarbodiimide); aromatic biscarbodiimides such as phenylene-bis(xylylcarbodiimide). can be mentioned. Specific examples of polycarbodiimides include aliphatic polycarbodiimides such as polyhexamethylenecarbodiimide, polytrimethylhexamethylenecarbodiimide, polycyclohexylenecarbodiimide, poly(methylenebiscyclohexylenecarbodiimide), and poly(isophoronecarbodiimide); poly(phenylenecarbodiimide); , poly(naphthylenecarbodiimide), poly(tolylenecarbodiimide), poly(methyldiisopropylphenylenecarbodiimide), poly(triethylphenylenecarbodiimide), poly(diethylphenylenecarbodiimide), poly(triisopropylphenylenecarbodiimide), poly(diisopropylphenylenecarbodiimide) ), poly(xylylenecarbodiimide), poly(tetramethylxylylenecarbodiimide), poly(methylene diphenylenecarbodiimide), and poly[methylenebis(methylphenylene)carbodiimide]. Commercially available carbodiimide resins include, for example, "Carbodilite V-02B", "Carbodilite V-03", "Carbodilite V-04K", "Carbodilite V-07" and "Carbodilite V-09" manufactured by Nisshinbo Chemical; Examples include "Stavaxol P", "Stavaxol P400", and "Hikasil 510" manufactured by Rhein Chemie. One type of carbodiimide resin may be used alone, or two or more types may be used in combination.

The acid anhydride resin may be a resin having one or more acid anhydride groups in one molecule, and preferably a resin having two or more acid anhydride groups in one molecule. Specific examples of acid anhydride resins include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, and hydrogenated methylnadic anhydride. , trialkyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride , pyromellitic anhydride, bensophenonetetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenyl sulfone Tetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan-1,3 Examples include polymeric acid anhydrides such as dione, ethylene glycol bis(anhydrotrimellitate), and styrene-maleic acid resin, which is a copolymer of styrene and maleic acid. Commercially available acid anhydride resins include, for example, "HNA-100", "MH-700", "MTA-15", "DDSA", and "OSA" manufactured by Shin Nippon Chemical Co.; and "OSA" manufactured by Mitsubishi Chemical Corporation. "YH-306", "YH-307"; "HN-2200", "HN-5500" manufactured by Hitachi Chemical; "EF-30", "EF-40", "EF-60", "EF" manufactured by Clay Valley -80'', etc. One type of acid anhydride resin may be used alone, or two or more types may be used in combination.

The amine resin may be a resin having one or more, preferably two or more, amino groups in one molecule. Examples of the amine resin include aliphatic amines, polyether amines, alicyclic amines, aromatic amines, etc. Among them, aromatic amines are preferred. The amine resin is preferably a primary amine or a secondary amine, and more preferably a primary amine. Specific examples of amine resins include 4,4'-methylenebis(2,6-dimethylaniline), 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, m -Phenylene diamine, m-xylylene diamine, diethyltoluenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diamino Biphenyl, 3,3'-dihydroxybenzidine, 2,2-bis(3-amino-4-hydroxyphenyl)propane, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethanediamine, 2,2- Bis(4-aminophenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy) ) benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, bis(4-(3 -aminophenoxy)phenyl)sulfone, and the like. Commercially available amine resins include, for example, "SEIKACURE-S" manufactured by Seika; "KAYABOND C-200S", "KAYABOND C-100", "Kayahard AA", and "Kayahard A-" manufactured by Nippon Kayaku Co., Ltd. Examples include "B", "Kayahard AS"; "Epicure W" manufactured by Mitsubishi Chemical Corporation; and "DTDA" manufactured by Sumitomo Seika Co., Ltd. One type of amine resin may be used alone, or two or more types may be used in combination.

Specific examples of benzoxazine resins include "JBZ-OP100D" and "ODA-BOZ" manufactured by JFE Chemical; "HFB2006M" manufactured by Showa Kobunshi Co., Ltd.; "P-d" and "F" manufactured by Shikoku Kasei Kogyo Co., Ltd. -a'', etc. One type of benzoxazine resin may be used alone, or two or more types may be used in combination.

The cyanate resin can be a resin having one or more, preferably two or more cyanate groups in one molecule. Examples of cyanate ester resins include bisphenol A dicyanate, polyphenol cyanate (oligo(3-methylene-1,5-phenylene cyanate)), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4' -ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanato)phenylpropane, 1,1-bis(4-cyanatophenylmethane), bis(4-cyanato-3,5-dimethylphenyl) ) Methane, bifunctional cyanate resins such as 1,3-bis(4-cyanatophenyl-1-(methylethylidene))benzene, bis(4-cyanatophenyl)thioether, and bis(4-cyanatophenyl)ether, phenol novolak and polyfunctional cyanate resins derived from cresol novolak and the like, prepolymers in which these cyanate resins are partially triazine-formed, and the like. Specific examples of cyanate ester resins include "PT30" and "PT60" (all phenol novolac type polyfunctional cyanate ester resins) manufactured by Lonza Japan, "BA230" and "BA230S75" (part or all of bisphenol A dicyanate). is triazinated to form a trimer). One type of cyanate SL resin may be used alone, or two or more types may be used in combination.

Examples of the thiol resin include trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), tris(3-mercaptopropyl)isocyanurate, and the like. One type of thiol resin may be used alone, or two or more types may be used in combination.

In a preferred embodiment, the thermosetting resin (B) includes an epoxy resin. In a more preferred embodiment, the thermosetting resin (B) includes a combination of an epoxy resin and a resin that can react with the epoxy resin to cure the resin composition. A resin capable of curing a resin composition by reacting with an epoxy resin is sometimes referred to as an "epoxy curing agent" hereinafter. Examples of the epoxy curing agent include phenol resins, active ester resins, carbodiimide resins, acid anhydride resins, amine resins, benzoxazine resins, cyanate ester resins, and thiol resins. Among the epoxy curing agents, phenolic resins and active ester resins are preferred. One type of epoxy curing agent may be used alone, or two or more types may be used in combination.

The active group equivalent of the epoxy curing agent is preferably 50 g/eq. ～3000g/eq. , more preferably 100g/eq. ～1000g/eq. , more preferably 100g/eq. ～500g/eq. , particularly preferably 100 g/eq. ～300g/eq. It is. Active group equivalent represents the mass of epoxy curing agent per equivalent of active group.

When using an epoxy resin and an epoxy curing agent in combination, the ratio of the number of epoxy groups in the epoxy resin to the number of active groups in the epoxy curing agent ("number of active groups in the epoxy curing agent"/"number of epoxy groups in the epoxy resin") is Preferably, there is a range. Specifically, the ratio ("number of active groups of epoxy curing agent"/"number of epoxy groups of epoxy resin") is preferably 0.1 or more, more preferably 0.2 or more, and even more preferably 0.3 or more. and is preferably 5.0 or less, more preferably 3.0 or less, particularly preferably 1.5 or less. "Number of epoxy groups in an epoxy resin" refers to the sum of all the values obtained by dividing the mass of nonvolatile components of the epoxy resin present in the resin composition by the epoxy equivalent. In addition, "the number of active groups of the epoxy curing agent" refers to the sum of all the values obtained by dividing the mass of the nonvolatile components of the epoxy curing agent present in the resin composition by the active group equivalent of the epoxy curing agent.

The amount of the thermosetting resin (B) in the resin composition is preferably 5% by mass or more, more preferably 10% by mass or more, particularly preferably 20% by mass, based on 100% by mass of the nonvolatile components of the resin composition. The content is preferably 70% by mass or less, more preferably 60% by mass or less, particularly preferably 50% by mass or less.

The amount of the thermosetting resin (B) in the resin composition is preferably 60% by mass or more, more preferably 70% by mass or more, particularly preferably 80% by mass, based on 100% by mass of the resin component of the resin composition. or more, preferably 99.9% by mass or less, more preferably 99% by mass or less.

The mass ratio of (A) imidazole compound and (B) thermosetting resin in the resin composition ((B) thermosetting resin/(A) imidazole compound) is preferably 100 or more, more preferably 200. Above, it is more preferably 300 or more, particularly preferably 400 or more, preferably 1000 or less, more preferably 900 or less, still more preferably 800 or less, particularly preferably 700 or less.

The resin composition may further contain (C) an inorganic filler. (C) The inorganic filler is usually contained in the resin composition in the form of particles.

(C) An inorganic compound is used as the material for the inorganic filler. (C) Materials for the inorganic filler include, for example, silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, and water. Aluminum oxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide , zirconium oxide, barium titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, silica and alumina are preferred, and silica is particularly preferred. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. Further, as the silica, spherical silica is preferable. (C) Inorganic fillers may be used alone or in combination of two or more.

(C) Commercially available inorganic fillers include, for example, "SP60-05" and "SP507-05" manufactured by Nippon Steel Chemical &Materials; "YC100C", "YA050C" and "YA050C" manufactured by Admatex. YA050C-MJE”, “YA010C”, “SC2500SQ”, “SO-C4”, “SO-C2”, “SO-C1”, “SC2050-SXF”; “UFP-30” manufactured by Denka; manufactured by Tokuyama Examples include "Silfill NSS-3N", "Silfill NSS-4N", and "Silfill NSS-5N".

(C) The average particle size of the inorganic filler is preferably 0.01 μm or more, more preferably 0.05 μm or more, even more preferably 0.1 μm or more, particularly preferably 0.2 μm or more, and preferably 10 μm or less, The thickness is more preferably 5 μm or less, further preferably 2 μm or less, particularly preferably 1 μm or less.

(C) The average particle size of the inorganic filler can be measured by a laser diffraction/scattering method based on Mie scattering theory. Specifically, it can be measured by creating the particle size distribution of the inorganic filler on a volume basis using a laser diffraction scattering type particle size distribution measuring device, and using the median diameter as the average particle size. The measurement sample can be obtained by weighing 100 mg of the inorganic filler and 10 g of methyl ethyl ketone into a vial and dispersing them using ultrasonic waves for 10 minutes. The measurement sample was measured using a laser diffraction particle size distribution measuring device using a light source wavelength of blue and red, and the volume-based particle size distribution of the inorganic filler was measured using a flow cell method. The average particle size can be calculated as the median diameter. Examples of the laser diffraction particle size distribution measuring device include "LA-960" manufactured by Horiba, Ltd.

(C) The specific surface area of the inorganic filler is preferably 0.1 m ² /g or more, more preferably 0.5 m ² /g or more, even more preferably 1 m ² /g or more, particularly preferably 3 m ² /g or more. It is preferably 100 m ² /g or less, more preferably 70 m ² /g or less, even more preferably 50 m ² /g or less, particularly preferably 40 m ² /g or less. The specific surface area of the inorganic filler is determined by adsorbing nitrogen gas onto the sample surface using a specific surface area measuring device (Macsorb HM-1210 manufactured by Mountec) according to the BET method, and calculating the specific surface area using the BET multipoint method. It can be measured by

(C) The inorganic filler is preferably treated with a surface treatment agent from the viewpoint of improving moisture resistance and dispersibility. Examples of surface treatment agents include fluorine-containing silane coupling agents, aminosilane coupling agents, epoxysilane coupling agents, mercaptosilane coupling agents, silane coupling agents, alkoxysilanes, organosilazane compounds, and titanate-based coupling agents. Coupling agents and the like can be mentioned. One type of surface treatment agent may be used alone, or two or more types may be used in any combination.

Commercially available surface treatment agents include, for example, "KBM403" (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM803" (3-mercaptopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd. "KBE903" (3-aminopropyltriethoxysilane) manufactured by Kagaku Kogyo, "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical, "SZ-31" manufactured by Shin-Etsu Chemical ( hexamethyldisilazane), "KBM103" (phenyltrimethoxysilane) manufactured by Shin-Etsu Chemical, "KBM-4803" (long chain epoxy type silane coupling agent) manufactured by Shin-Etsu Chemical, "KBM-" manufactured by Shin-Etsu Chemical 7103'' (3,3,3-trifluoropropyltrimethoxysilane).

The degree of surface treatment with the surface treatment agent is preferably within a specific range from the viewpoint of improving the dispersibility of the inorganic filler. Specifically, 100% by mass of the inorganic filler is preferably surface-treated with 0.2% by mass to 5% by mass of a surface treatment agent, and preferably 0.2% by mass to 3% by mass of a surface treatment agent. It is more preferable that the surface be treated, and it is even more preferable that the surface be treated with 0.3% by mass to 2% by mass of a surface treatment agent.

The degree of surface treatment by the surface treatment agent can be evaluated by the amount of carbon per unit surface area of the inorganic filler. The amount of carbon per unit surface area of the inorganic filler is preferably 0.02 mg/m ² or more, more preferably 0.1 mg/m ² or more, and 0.2 mg/m ² from the viewpoint of improving the dispersibility of the inorganic filler. The above is more preferable. On the other hand, from the viewpoint of preventing an increase in the melt viscosity of the resin composition, the amount is preferably 1.0 mg/m ² or less, more preferably 0.8 mg/m ² or less, and even more preferably 0.5 mg/m ² or less.

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

The amount of the inorganic filler (C) in the resin composition is preferably 20% by mass or more, more preferably 40% by mass or more, particularly preferably 60% by mass, based on 100% by mass of the nonvolatile components in the resin composition. The content is preferably 90% by mass or less, more preferably 85% by mass or less, particularly preferably 80% by mass or less.

The resin composition may further contain (D) a thermoplastic resin. The (D) thermoplastic resin does not include (A) an imidazole compound, (B) a thermosetting resin, or (C) an inorganic filler.

(D) Thermoplastic resins include, for example, phenoxy resins, polyimide resins, polyvinyl acetal resins, polyolefin resins, polybutadiene resins, polyamideimide resins, polyetherimide resins, polysulfone resins, polyethersulfone resins, polyphenylene ether resins, and polycarbonate resins. , polyetheretherketone resin, polyester resin, and the like. (D) The thermoplastic resin may be used alone or in combination of two or more.

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

Specific examples of polyimide resins include "SLK-6100" manufactured by Shin-Etsu Chemical Co., Ltd., "Ricacoat SN20" and "Ricacoat PN20" manufactured by Shinnihon Rika Co., Ltd., and the like. Specific examples of polyimide resins include linear polyimides obtained by reacting bifunctional hydroxyl group-terminated polybutadiene, diisocyanate compounds, and tetrabasic acid anhydrides (polyimide described in JP-A No. 2006-37083), polysiloxane skeletons, etc. Examples include modified polyimides such as polyimides containing polyimides (polyimides described in JP-A-2002-12667 and JP-A-2000-319386, etc.).

Examples of the polyvinyl acetal resin include polyvinyl formal resin and polyvinyl butyral resin, with polyvinyl butyral resin being preferred. Specific examples of polyvinyl acetal resin include Denka Butyral 4000-2, Denka Butyral 5000-A, Denka Butyral 6000-C, and Denka Butyral 6000-EP manufactured by Denki Kagaku Kogyo; Sekisui Chemical Co., Ltd. Examples include the S-LEC BH series, BX series (for example, BX-5Z), KS series (for example, KS-1), BL series, and BM series manufactured by the company.

Examples of polyolefin resins include ethylene copolymers such as low density polyethylene, ultra-low density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-methyl acrylate copolymer. Polymer resin; examples include polyolefin polymers such as polypropylene and ethylene-propylene block copolymers.

Examples of polybutadiene resins include hydrogenated polybutadiene skeleton-containing resins, hydroxy group-containing polybutadiene resins, phenolic hydroxyl group-containing polybutadiene resins, carboxy group-containing polybutadiene resins, acid anhydride group-containing polybutadiene resins, epoxy group-containing polybutadiene resins, and isocyanate group-containing polybutadiene resins. Examples include polybutadiene resin, urethane group-containing polybutadiene resin, polyphenylene ether-polybutadiene resin, and the like.

Specific examples of the polyamide-imide resin include "Viromax HR11NN" and "Viromax HR16NN" manufactured by Toyobo. Specific examples of polyamide-imide resins include modified polyamide-imides such as "KS9100" and "KS9300" (polysiloxane skeleton-containing polyamide-imide) manufactured by Hitachi Chemical.

A specific example of the polyether sulfone resin includes "PES5003P" manufactured by Sumitomo Chemical Co., Ltd.

Specific examples of the polysulfone resin include polysulfone "P1700" and "P3500" manufactured by Solvay Advanced Polymers.

A specific example of the polyphenylene ether resin includes "NORYL SA90" manufactured by SABIC. A specific example of the polyetherimide resin includes "Ultem" manufactured by GE.

Examples of the polycarbonate resin include hydroxy group-containing carbonate resins, phenolic hydroxyl group-containing carbonate resins, carboxy group-containing carbonate resins, acid anhydride group-containing carbonate resins, isocyanate group-containing carbonate resins, urethane group-containing carbonate resins, and the like. Specific examples of polycarbonate resins include "FPC0220" manufactured by Mitsubishi Gas Chemical Co., Ltd., "T6002" and "T6001" (polycarbonate diol) manufactured by Asahi Kasei Chemicals, and "C-1090" and "C-2090" manufactured by Kuraray Corporation. , "C-3090" (polycarbonate diol), and the like. Specific examples of polyetheretherketone resins include "Sumiploy K" manufactured by Sumitomo Chemical Co., Ltd., and the like.

Examples of the polyester resin include polyethylene terephthalate resin, polyethylene naphthalate resin, polybutylene terephthalate resin, polybutylene naphthalate resin, polytrimethylene terephthalate resin, polytrimethylene naphthalate resin, polycyclohexane dimethyl terephthalate resin, and the like.

(D) The weight average molecular weight (Mw) of the thermoplastic resin is preferably larger than 5,000, more preferably 8,000 or more, even more preferably 10,000 or more, particularly preferably 20,000 or more, and preferably is 100,000 or less, more preferably 70,000 or less, even more preferably 60,000 or less, particularly preferably 50,000 or less.

The amount of the thermoplastic resin (D) in the resin composition is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, particularly preferably is 0.2% by mass or more, preferably 20% by mass or less, more preferably 10% by mass or less, particularly preferably 5% by mass or less.

The amount of the thermoplastic resin (D) in the resin composition is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, particularly preferably is 1% by mass or more, preferably 30% by mass or less, more preferably 20% by mass or less, particularly preferably 10% by mass or less.

The resin composition may further contain (E) a flame retardant. The flame retardant (E) does not include the above-mentioned (A) imidazole compounds, (B) thermosetting resins, (C) inorganic fillers, or (D) thermoplastic resins. Examples of the flame retardant (E) include phosphazene compounds, organic phosphorus flame retardants, organic nitrogen-containing phosphorus compounds, nitrogen compounds, silicone flame retardants, and metal hydroxides. One type of flame retardant may be used alone, or two or more types may be used in combination.

Examples of flame retardants include "SPH-100", "SPS-100", "SPB-100", and "SPE-100" (phosphazenes) manufactured by Otsuka Chemical; "FP-100" manufactured by Fushimi Pharmaceutical Co., Ltd. ", "FP-110", "FP-300", "FP-400" (phosphazenes); Sankosha's "HCA-NQ", "HCA-HQ", "HCA-HQ-HST" (phosphinic acid Ester (containing phenolic hydroxyl group); "PX-200", "PX-201", "PX-202", "CR-733S", "CR-741", "CR-747" manufactured by Daihachi Chemical Industry Co., Ltd. (phosphate ester), etc.

The amount of the flame retardant (E) in the resin composition is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably It is 0.3% by mass or more. The upper limit is preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 1% by mass or less.

The resin composition may further contain (F) an arbitrary additive. (F) Optional additives include, for example, curing catalysts other than imidazole compounds; radically polymerizable compounds; organometallic compounds such as organocopper compounds, organozinc compounds, and organocobalt compounds; phthalocyanine blue, phthalocyanine green, and iodine. Coloring agents such as green, diazo yellow, crystal violet, titanium oxide, and carbon black; Polymerization inhibitors such as hydroquinone, catechol, pyrogallol, and phenothiazine; Leveling agents such as silicone leveling agents and acrylic polymer leveling agents; bentone, montmorillonite, etc. thickeners; antifoaming agents such as silicone antifoaming agents, acrylic antifoaming agents, fluorine antifoaming agents, and vinyl resin antifoaming agents; ultraviolet absorbers such as benzotriazole ultraviolet absorbers; urea silane, etc. adhesion improvers; adhesion agents such as triazole adhesion agents, tetrazole adhesion agents, and triazine adhesion agents; antioxidants such as hindered phenol antioxidants; stilbene derivatives, etc. Optical brightener; Surfactants such as fluorine surfactants and silicone surfactants; Phosphate dispersants, polyoxyalkylene dispersants, acetylene dispersants, silicone dispersants, anionic dispersants , dispersants such as cationic dispersants; borate stabilizers, titanate stabilizers, aluminate stabilizers, zirconate stabilizers, isocyanate stabilizers, carboxylic acid stabilizers, carboxylic acid anhydride stabilizers, etc. stabilizers; photopolymerization initiation aids such as tertiary amines; photosensitizers such as pyrarizones, anthracenes, coumarins, xanthones, and thioxanthones; (F) Arbitrary additives may be used alone or in combination of two or more.

The resin composition includes the above-mentioned (A) imidazole compound, (B) thermosetting resin, (C) inorganic filler, (D) thermoplastic resin, (E) flame retardant, and (F) optional additives. In combination with the non-volatile components, it may further contain (G) a solvent as an optional volatile component. (G) As the solvent, an organic solvent is usually used. Examples of organic solvents include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, and γ-butyrolactone. Ester solvents; ether solvents such as tetrahydropyran, tetrahydrofuran, 1,4-dioxane, diethyl ether, diisopropyl ether, dibutyl ether, diphenyl ether, anisole; alcohol solvents such as methanol, ethanol, propanol, butanol, ethylene glycol; acetic acid Ether ester solvents such as 2-ethoxyethyl, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl diglycol acetate, γ-butyrolactone, methyl methoxypropionate; methyl lactate, ethyl lactate, methyl 2-hydroxyisobutyrate, etc. Ester alcohol solvents such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, diethylene glycol monobutyl ether (butyl carbitol); N,N-dimethylformamide, N, Amide solvents such as N-dimethylacetamide and N-methyl-2-pyrrolidone; Sulfoxide solvents such as dimethyl sulfoxide; Nitrile solvents such as acetonitrile and propionitrile; Aliphatic solvents such as hexane, cyclopentane, cyclohexane, and methylcyclohexane Hydrocarbon solvents include aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene. (G) Solvents may be used alone or in combination of two or more.

(G) The amount of the solvent is not particularly limited, but when all the components in the resin composition are 100% by mass, for example, 60% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less It may be less than 15% by mass, less than 10% by mass, etc., and may be 0% by mass.

The thickness of the resin composition layer is preferably 100 μm or less, more preferably 80 μm or less, and even more preferably 50 μm or less, from the viewpoint of making the printed wiring board thinner. The lower limit of the thickness of the resin composition layer is not particularly limited, but may be 5 μm or more, 10 μm or more, etc.

-Production method of resin sheet-
The method for manufacturing the resin sheet is not particularly limited. The resin sheet can be manufactured, for example, by a method including applying a resin composition onto a release layer of a support. When a liquid (varnish-like) resin composition is used, the resin composition may be applied directly onto the release layer of the support. Alternatively, a liquid (varnish-like) resin composition may be prepared by mixing the solvent and the nonvolatile components of the resin composition, and this may be applied onto the release layer. Examples of the solvent include those similar to the solvent (G) described as a component of the resin composition. Further, the coating may be performed using a coating device such as a die coater.

The method for manufacturing a resin sheet may include drying the applied resin composition, if necessary. Drying may be carried out by a drying method such as heating or blowing hot air. Drying conditions are not particularly limited, but drying is carried out so that the content of the solvent in the resin composition layer is usually 10% by mass or less, preferably 5% by mass or less. Although it may vary depending on the boiling point of the solvent in the resin composition, for example, when using a resin composition containing 30% by mass to 60% by mass of solvent, the resin can be dried by drying at 50°C to 150°C for 3 to 10 minutes. A composition layer can be formed.

The method for manufacturing a resin sheet may further include an arbitrary step. For example, the method for producing a resin sheet may include laminating a resin composition layer and a protective film similar to a support. The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. When the protective film is attached, it is possible to suppress the adhesion of dust and scratches to the surface of the resin composition layer. Usually, the protective film is removed before laminating the resin sheet and the inner layer substrate in step (I).

[Step (I): Lamination of resin sheet and inner layer substrate]
A method for manufacturing a printed wiring board according to an embodiment of the present invention includes a step (I) of laminating a resin sheet on an inner layer substrate so that the resin composition layer is bonded to the inner layer substrate. The "inner layer substrate" used in step (I) is a member that becomes a substrate of a printed wiring board, and includes, for example, a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, and a thermosetting polyphenylene ether substrate. etc. Further, the substrate may have a conductor layer on one or both sides, and this conductor layer may be patterned. An inner layer board in which a conductor layer (circuit) is formed on one or both sides of the board is sometimes referred to as an "inner layer circuit board." Further, when manufacturing a printed wiring board, an intermediate product on which an insulating layer and/or a conductive layer is further formed is also included in the above-mentioned "inner layer board". If the printed wiring board is a circuit board with built-in components, an inner layer board with built-in components may be used.

Lamination of the inner layer substrate and the resin sheet can be performed, for example, by heat-pressing the resin sheet to the inner layer substrate from the support body side. Examples of the member for heat-pressing the resin sheet to the inner layer substrate (hereinafter also referred to as "heat-pressing member") include a heated metal plate (SUS mirror plate, etc.) or a metal roll (SUS roll, etc.). Note that, instead of pressing the thermocompression bonding member directly onto the resin sheet, it is preferable to press the resin sheet through an elastic material such as heat-resistant rubber so that the resin sheet sufficiently follows the surface irregularities of the inner layer substrate.

The inner layer substrate and the resin sheet may be laminated by a vacuum lamination method. In the vacuum lamination method, the heat-pressing temperature is preferably in the range of 60°C to 160°C, more preferably 80°C to 140°C, and the heat-pressing pressure is preferably in the range of 0.098 MPa to 1.77 MPa, more preferably 0. The pressure is in the range of .29 MPa to 1.47 MPa, and the heat-pressing time is preferably in the range of 20 seconds to 400 seconds, more preferably 30 seconds to 300 seconds. Lamination is preferably carried out under reduced pressure conditions of 26.7 hPa or less.

Lamination can be performed using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include a vacuum pressure laminator manufactured by Meiki Seisakusho, a vacuum applicator manufactured by Nikko Materials, and a batch vacuum pressure laminator.

After lamination, the laminated resin sheets may be smoothed under normal pressure (atmospheric pressure), for example, by pressing a thermocompression bonding member from the support side. The pressing conditions for the smoothing treatment can be the same as the conditions for the heat-pressing of the lamination described above. The smoothing process can be performed using a commercially available laminator. Note that the lamination and smoothing treatment may be performed continuously using the above-mentioned commercially available vacuum laminator.

[Step (II): Heat curing of resin composition layer]
The method for manufacturing a printed wiring board according to an embodiment of the present invention includes, after step (I), a step (II) of thermosetting the resin composition layer in a nitrogen atmosphere. The insulating layer can be formed by thermosetting the resin composition layer. The formed insulating layer contains a cured product of the resin composition, preferably only a cured product of the resin composition.

Thermal curing of the resin composition layer in step (II) is performed in a nitrogen atmosphere. Since the nitrogen atmosphere is filled with nitrogen gas, the oxygen concentration in the nitrogen atmosphere is low. The range of oxygen concentration in the nitrogen atmosphere is preferably 5% by mass or less, more preferably 3% by mass or less, particularly preferably 1% by mass or less, and ideally 0% by mass.

The pressure condition of the nitrogen atmosphere in which step (II) is performed may be normal pressure or reduced pressure. In one example, the range of specific pressure conditions of the nitrogen atmosphere is preferably 0.075 mmHg (0.1 hPa) or more, more preferably 1 mmHg (1.3 hPa) or more, and preferably 3751 mmHg (5000 hPa) or less, more preferably is 1875 mmHg (2500 hPa) or less.

Thermal curing of the resin composition layer in step (II) includes:
(II-2) Subjecting the resin composition layer to a heat treatment to maintain it at a temperature T1,
(II-4) subjecting the resin composition layer to a heat treatment in which the resin composition layer is held at a temperature T2 higher than the temperature T1;
In this order. Hereinafter, the heat treatment step held at temperature T1 may be referred to as "precure step (II-2)." Further, the heat treatment step held at temperature T2 is sometimes referred to as a "post-cure step (II-4)."

Usually, before the precure step (II-2), the resin composition layer is at a heating start temperature T0 lower than the temperature T1. The temperature increase start temperature T0 may be, for example, room temperature. Therefore, the step (II) may include a step (II-1) of heating the resin composition layer from the heating start temperature T0 to the temperature T1 before the precure step (II-2). The range of the temperature increase rate in this step (II-1) is preferably 0.5°C/min or more, more preferably 1°C/min or more, and even more preferably 1. 5°C/min or more, more preferably 2°C/min or more, particularly preferably 2.5°C/min or more, preferably 30°C/min or less, more preferably 25°C/min or less, even more preferably 20°C /min, more preferably 15°C/min or less, particularly preferably 10°C/min or less. The temperature increase rate in step (II-1) may be constant or may be varied.

In the precure step (II-2), the resin composition layer is subjected to a heat treatment maintained at a temperature T1. The heating temperature T1 in this precure step (II-2) is set in a temperature range higher than room temperature and lower than temperature T2. The specific range of the heating temperature T1 is preferably 50°C or higher, more preferably 60°C or higher, still more preferably 70°C or higher, particularly preferably 80°C or higher, from the viewpoint of significantly obtaining the effects of the present invention. The temperature is preferably lower than 150°C, more preferably 140°C or lower, and even more preferably 130°C or lower. In the precure step (II-2), maintaining the resin composition layer at temperature T1 means not only maintaining the temperature of the resin composition layer at a constant temperature, but also maintaining the resin composition layer within a range that does not significantly impair the effects of the present invention. Variations in the temperature of the composition layer are also included. For example, in the precure step (II-2), the temperature of the resin composition layer may vary within a range of ±10°C, a range of ±8°C, or a range of ±5°C. However, even if the temperature of the resin composition layer fluctuates in this way, the temperature of the resin composition layer in the precure step (II-2) should be within the above-mentioned preferred range, for example, 50°C or more and less than 150°C. It is preferably within the range. Among these, it is particularly preferable that the temperature of the resin composition layer is constant without fluctuation in the precure step (II-2).

The range of time for maintaining the resin composition layer at the heating temperature T1 in the precure step (II-2) depends on the composition of the resin composition and the value of the heating temperature T1, but is preferably from the viewpoint of significantly obtaining the effects of the present invention. is 10 minutes or more, more preferably 15 minutes or more, particularly preferably 20 minutes or more, and preferably 150 minutes or less, more preferably 120 minutes or less, particularly preferably 120 minutes or less.

Usually, before the post-cure step (II-4), the resin composition layer is at a temperature lower than temperature T2. Therefore, step (II) may include a step (II-3) of heating the resin composition layer to temperature T2 after the pre-cure step (II-2) and before the post-cure step (II-4). . The range of the temperature increase rate in this step (II-3) is preferably 0.5°C/min or more, more preferably 1°C/min or more, and even more preferably 1. 5°C/min or more, more preferably 2°C/min or more, particularly preferably 2.5°C/min or more, preferably 30°C/min or less, more preferably 25°C/min or less, even more preferably 20°C /min, more preferably 15°C/min or less, particularly preferably 10°C/min or less. The temperature increase rate in step (II-3) may be constant or may be varied.

In the post-cure step (II-4), the resin composition layer is subjected to a heat treatment maintained at a temperature T2. The heating temperature T2 in the post-cure step (II-4) is set to a higher temperature than the temperature T1. The specific range of the heating temperature T2 is preferably 150°C or higher, more preferably 155°C or higher, still more preferably 160°C or higher, particularly preferably 170°C or higher, from the viewpoint of significantly obtaining the effects of the present invention. The temperature is preferably 250°C or lower, more preferably 230°C or lower, even more preferably 220°C or lower, even more preferably 210°C or lower, particularly preferably 200°C or lower. In the post-cure step (II-4), maintaining the resin composition layer at temperature T2 means not only maintaining the temperature of the resin composition layer at a constant temperature, but also maintaining the temperature of the resin composition layer at a constant temperature within a range that does not significantly impair the effects of the present invention. It is also included that the temperature of the resin composition layer varies. For example, in the post-cure step (II-4), the temperature of the resin composition layer may vary within a range of ±10°C, a range of ±8°C, or a range of ±5°C. However, even if the temperature of the resin composition layer fluctuates in this way, the temperature of the resin composition layer in the post-cure step (II-4) should be within the above-mentioned preferred range, for example, 150°C or more and 250°C or less. It is preferable that it is within the range of . Among these, it is particularly preferable that the temperature of the resin composition layer is constant without fluctuation in the post-cure step (II-4).

The difference T2-T1 between the heating temperature T1 in the pre-cure step (II-2) and the heating temperature T2 in the post-cure step (II-4) must be within a specific range from the viewpoint of significantly obtaining the effects of the present invention. is preferred. Specifically, the difference T2-T1 is preferably 20°C or higher, more preferably 30°C or higher, particularly preferably 40°C or higher, and preferably 150°C or lower, more preferably 140°C or lower, and even more preferably is 130°C or lower, particularly preferably 120°C or lower. When the temperature of the resin composition layer fluctuates in the pre-cure step (II-2) and/or the post-cure step (II-4), the median temperature of the resin composition in the pre-cure step (II-2) and the post-cure The difference from the median temperature of the resin composition in step (II-4) is preferably within the above range.

The range of time for holding the resin composition layer at the heating temperature T2 in the post-curing step (II-4) depends on the composition of the resin composition and the value of the heating temperature T2, but from the viewpoint of significantly obtaining the effects of the present invention, Preferably it is 10 minutes or more, more preferably 15 minutes or more, particularly preferably 20 minutes or more, and preferably 150 minutes or less, more preferably 120 minutes or less.

After the heat treatment at temperature T1 in the precure step (II-2), the resin composition layer may be cooled once and then subjected to the heat treatment at the heating temperature T2 in the post-cure step (II-4). Alternatively, after the heat treatment at temperature T1 in the precure step (II-2), the resin composition layer may be subjected to heat treatment at temperature T2 in the precure step (II-4) without cooling. .

The heat treatment in the pre-cure step (II-2) and the heat treatment in the post-cure step (II-4) may be performed using the same heat treatment apparatus. Further, the heat treatment in the precure step (II-2) is performed using a first heat treatment device, and the heat treatment in the post-cure step (II-4) is performed using a second heat treatment device different from the first heat treatment device. It may also be carried out using a processing device. The heat treatment device is not particularly limited as long as it can thermoset the resin composition layer. As the heat treatment device, for example, an oven, a hot press, etc. can be used. For example, after performing heat treatment in the precure step (II-2) using an oven adjusted to temperature T1, the inner layer substrate and resin sheet are transferred to an oven adjusted to temperature T2, and the post-cure step (II-2) is performed using an oven adjusted to temperature T1. The heat treatment in 4) may be performed. Alternatively, after performing the heat treatment in the pre-cure step (II-2) using a temperature programmable heat treatment device, the temperature is raised from temperature T1 to temperature T2, and then the heat treatment in the post-cure step (II-4) is performed. Processing may be performed.

Step (II) may further include an arbitrary step in combination with steps (II-1) to (II-4) described above. For example, step (II) may include a step of subjecting the resin composition layer to a heat treatment in which the resin composition layer is maintained at a heating temperature other than the above-mentioned temperatures T1 and T2. That is, step (II) is not limited to two steps of heat treatment, but may include three or more steps of heat treatment.

[Step (III): Peeling off the support]
The method for manufacturing a printed wiring board according to an embodiment of the present invention includes a step (III) of peeling off the support after step (II). According to this embodiment, it is possible to suppress the support and the insulating layer as a cured resin composition layer from sticking together. Therefore, peeling defects can be suppressed, and the support can be peeled off smoothly.

Usually, the support is peeled off by pulling the support relative to the insulating layer. For example, the insulating layer and the inner layer substrate may be transported with the support fixed, and then the support may be peeled off. Alternatively, for example, the support may be peeled off by pulling the support with the insulating layer and inner layer substrate fixed. Furthermore, for example, the insulating layer and inner layer substrate may be conveyed while pulling the support, and the support may be peeled off.

Typically, peeling of the support is accomplished by pulling the support relative to the surface of the insulating layer in a peeling direction at a particular angle. There is no particular restriction on the range of the angle that the peeling direction makes with respect to the surface of the insulating layer. From the viewpoint of facilitating peeling of the support, the range of the angle is preferably 0° or more, preferably 70° or less, more preferably 60° or less, still more preferably 50° or less, and even more preferably The angle is 40° or less, more preferably 30° or less, even more preferably 20° or less, particularly preferably 10° or less.

The temperature conditions for peeling off the support are not particularly limited. From the viewpoint of reducing the energy required for manufacturing printed wiring boards, peeling of the support is usually performed at room temperature or a temperature close to it. Therefore, the inner substrate, the insulating layer, and the support are usually cooled after the step (II), and then the support is peeled off. The specific temperature range in which the support is peeled off is preferably in the range of 10°C or higher and 40°C. Further, the temperature decreasing rate in the step of cooling from temperature T2 is not particularly limited, but is preferably 0.5°C/min or more, more preferably 1°C/min or more, still more preferably 1.5°C/min or more, and Preferably 2°C/min or higher, particularly preferably 2.5°C/min or higher, preferably 30°C/min or lower, more preferably 25°C/min or lower, even more preferably 20°C/min or lower, even more preferably It is 15°C/min or less, particularly preferably 10°C/min or less.

In the printed wiring board manufacturing method according to the present embodiment, peeling defects between the insulating layer and the support are suppressed, so it is possible to increase the peeling speed of the support. From the viewpoint of contributing to improving the production speed of printed wiring boards, it is preferable that the peeling speed is high. The specific range of peeling speed is preferably 1 m/min or more, more preferably 2 m/min or more, even more preferably 3 m/min or more, even more preferably 4 m/min or more, particularly preferably 5 m/min or more. The upper limit is not particularly limited, and may be, for example, 20 m/min or less, 10 m/min or less, etc.

[Process (IV): Drilling]
The method for manufacturing a printed wiring board according to an embodiment of the present invention may further include an arbitrary step. For example, the method for manufacturing a printed wiring board according to the present embodiment may include a step (IV) of drilling holes in the insulating layer. This step (IV) may be performed before step (III) or after step (III).

Step (IV) includes forming holes such as via holes and through holes in the insulating layer. The holes may be formed using, for example, a drill, laser, or plasma, depending on the composition of the resin composition used to form the insulating layer. The size and shape of the hole may be determined as appropriate depending on the design of the printed wiring board.

[Step (V): Roughening treatment]
The method for manufacturing a printed wiring board according to an embodiment of the present invention may include a step (V) of roughening the insulating layer. This step (V) is usually performed after step (III), but may be performed before step (III). Moreover, it is preferable that step (V) is performed after step (IV). For example, after performing the step (V) of forming holes in the insulating layer and roughening it in the step (IV), the step (III) of peeling off the support may be performed. When step (V) is performed after forming the holes in step (IV), it is possible to remove resin residue (smear) that may remain in the holes.

The procedure and conditions for the roughening treatment are not particularly limited, and known procedures and conditions used for forming an insulating layer of a printed wiring board may be employed. For example, the insulating layer may be roughened by performing a swelling treatment using a swelling liquid, a roughening treatment using an oxidizing agent, and a neutralization treatment using a neutralizing liquid in this order.

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

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

The neutralizing solution used in the roughening treatment is preferably an acidic aqueous solution, and a commercially available product includes, for example, "Reduction Solution Securigant P" manufactured by Atotech Japan. The treatment with the neutralizing liquid can be carried out, for example, by immersing the treated surface that has been roughened with an oxidizing agent in the neutralizing liquid at 30° C. to 80° C. for 5 minutes to 30 minutes. From the viewpoint of workability, it is preferable to immerse the object that has been roughened with an oxidizing agent in a neutralizing solution at 40° C. to 70° C. for 5 minutes to 20 minutes.

In one example, the arithmetic mean roughness (Ra) of the surface of the insulating layer after the roughening treatment is preferably 500 nm or less, more preferably 400 nm or less, and still more preferably 300 nm or less. The lower limit is not particularly limited, and may be, for example, 1 nm or more, 2 nm or more, etc. Further, the root mean square roughness (Rq) of the surface of the insulating layer after the roughening treatment is preferably 500 nm or less, more preferably 400 nm or less, and still more preferably 300 nm or less. The lower limit is not particularly limited, and may be, for example, 1 nm or more, 2 nm or more, etc. The arithmetic mean roughness (Ra) and root mean square roughness (Rq) of the surface of the insulating layer can be measured using a non-contact surface roughness meter.

[Step (VI): Formation of conductor layer]
The method for manufacturing a printed wiring board according to an embodiment of the present invention may include a step (VI) of forming a conductor layer. In this step (VI), a conductor layer is usually formed on the insulating layer. Therefore, step (VI) is usually performed after step (III). In a preferred embodiment, step (IV), step (V) and step (VI) are performed in this order.

The conductor material used for the conductor layer is not particularly limited. In a preferred embodiment, the conductor layer includes one or more selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. Contains metal. The conductor layer may be a single metal layer or an alloy layer. Examples of the alloy layer include a layer formed from an alloy of two or more metals selected from the above group (for example, a nickel-chromium alloy, a copper-nickel alloy, and a copper-titanium alloy). Among these, from the viewpoint of versatility in forming conductor layers, cost, ease of patterning, etc., monometallic layers of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, nickel-chromium alloys, copper, etc. An alloy layer of nickel alloy or copper/titanium alloy is preferable, a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or an alloy layer of nickel/chromium alloy is more preferable, and a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper is more preferable. A metal layer is more preferred.

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

The thickness of the conductor layer depends on the desired printed wiring board design, but is generally between 3 μm and 35 μm, preferably between 5 μm and 30 μm.

The conductor layer may be formed by plating, for example. To give a specific example, a conductive layer having a desired wiring pattern can be formed by plating the surface of an insulating layer using a conventionally known technique such as a semi-additive method or a fully additive method. From the viewpoint of ease of production, a semi-additive method is preferred. An example of forming a conductor layer by a semi-additive method will be shown below.

First, a plating seed layer is formed on the surface of the insulating layer by electroless plating. Next, a mask pattern is formed on the formed plating seed layer to expose a portion of the plating seed layer corresponding to a desired wiring pattern. After forming a metal layer on the exposed plating seed layer by electrolytic plating, the mask pattern is removed. Thereafter, the unnecessary plating seed layer is removed by a removal method such as etching, and a conductor layer having a desired wiring pattern can be formed.

If necessary, the formation of the insulating layer and conductive layer in steps (I) to (VI) may be repeated to produce a multilayer printed wiring board.

[Other processes]
The method for manufacturing a printed wiring board according to an embodiment of the present invention may further include any steps in combination with the steps described above.

For example, a long resin sheet that is continuously conveyed in the longitudinal direction may be used. In this case, the resin sheet is usually drawn out from a roll of resin sheets, and the drawn resin sheet is supplied onto the inner layer substrate. In this case, the method for manufacturing a printed wiring board may include the step of cutting the long resin sheet into appropriate dimensions. The cutting of the resin sheet may be performed before step (I) or after step (I).

For example, a resin sheet including a protective film that protects the resin composition layer may be used. The protective film is usually provided on the opposite side of the resin composition layer from the support. In this case, the method for manufacturing a printed wiring board may include a step of removing the protective film. Usually, the protective film is removed before step (I).

[Uses of printed wiring boards]
A printed wiring board manufactured by the manufacturing method according to an embodiment of the present invention can be used for a wide range of purposes, and can be applied to semiconductor devices, for example. This semiconductor device includes the printed wiring board described above. Specific examples of semiconductor devices include various semiconductor devices used in electrical products (e.g., computers, mobile phones, digital cameras, televisions, etc.) and vehicles (e.g., motorcycles, automobiles, trains, ships, aircraft, etc.). Can be mentioned. However, the printed wiring board may be applied to uses other than those described above.

Hereinafter, the present invention will be specifically explained by showing examples. However, the present invention is not limited to the following examples. In the following description, "parts" and "%" representing amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified. Further, the operations described below were performed in an atmospheric environment at normal temperature and normal pressure (25° C., 1 atm) unless otherwise specified.

<Production Example 1: Production of support 1 provided with a release layer containing acrylic resin>
(Manufacture of acrylic resin (A1))
In a temperature-adjustable reactor equipped with a stirrer, a thermometer, and a condenser, 500 parts by weight of toluene, 80 parts by weight of stearyl methacrylate (carbon number 18 in the alkyl chain), 15 parts by weight of methacrylic acid, and 5 parts by weight of 2-hydroxyethyl methacrylate. and 1 part of azobisisobutyronitrile were added dropwise using a dropper at a reaction temperature of 85° C. over 4 hours to carry out a polymerization reaction. Thereafter, the reaction was completed by aging at the same temperature for 2 hours to obtain acrylic resin (A). This acrylic resin (A) was dissolved in water containing 5% by mass of isopropyl alcohol and 5% by mass of n-butyl cellosolve to obtain a resin solution containing acrylic resin (A1) as a mold release compound.

(Preparation of acrylic resin (B1))
In a stainless steel reaction vessel, methyl methacrylate (a), hydroxyethyl methacrylate (b), aromatic urethane acrylate oligomer (“EBECRYL 220” manufactured by Daicel Allnex Corporation, number of acryloyl groups is 6) (c), (a) )/(b)/(c)=94/1/5 mass ratio. Furthermore, 2 parts by mass of sodium dodecylbenzenesulfonate as an emulsifier was added to the reaction container based on the total of 100 parts by mass of (a) + (b) + (c), and the mixture was stirred. was prepared.

Next, a reaction apparatus equipped with a stirrer, a reflux condenser, a thermometer, and a dropping funnel was prepared. 60 parts by mass of the above mixed solution (1), 200 parts by mass of isopropyl alcohol, and 5 parts by mass of potassium persulfate as a polymerization initiator were added to the reactor and heated to 60° C. to prepare a mixed solution (2). . The mixed solution (2) was kept heated at 60° C. for 20 minutes.

Next, a mixed solution (3) consisting of 40 parts by mass of the mixed solution (1), 50 parts by mass of isopropyl alcohol, and 5 parts by mass of potassium persulfate was prepared. Mixed liquid (3) was dropped into mixed liquid (2) over 2 hours using a dropping funnel to prepare mixed liquid (4).

Thereafter, the mixed solution (4) was kept heated at 60° C. for 2 hours. The obtained liquid mixture (4) was cooled to 50° C. or lower, and then transferred to a container equipped with a stirrer and pressure reduction equipment. Add 60 parts by mass of 25% ammonia water and 900 parts by mass of pure water to this container, and collect isopropyl alcohol and unreacted monomers under reduced pressure while heating to 60°C. A composition containing an acrylic resin (B1) was obtained.

(Preparation of mold release agent (1))
A resin solution containing acrylic resin (A1) and a composition containing acrylic resin (B1) are mixed at a mass ratio (solid content mass ratio) of acrylic resin (A1) and acrylic resin (B1) of (A1)/(B1). An intermediate composition was obtained by mixing in a ratio of 20/80. Furthermore, a fluorine-based surfactant ("Pluscoat (registered trademark) RY-2" manufactured by Gooh Kagaku Kogyo Co., Ltd.) was added to this intermediate composition in an amount of 0.1 part by mass based on 100 parts by mass of the entire intermediate composition. The release agent (1) was obtained as a liquid acrylic resin composition.

(Manufacture of support 1)
A PET film (“T60” (thickness: 38 μm) manufactured by Toray Industries, Inc.) was prepared as a supporting base material. A mold release agent (1) was coated on one side of this supporting base material using a gravure coater and dried to form a mold release layer with a thickness of 0.1 μm. Through the above operations, a support 1 including a support base material and a release layer containing an acrylic resin was obtained.

<Production Example 2: Production of support 2 provided with a release layer not containing acrylic resin>
(Preparation of polyolefin resin (C1))
280 g of propylene-ethylene copolymer (propylene/ethylene = 99/1 (mass ratio)) was heated and melted in a four-necked flask under a nitrogen atmosphere. Thereafter, 5.5 g of dicumyl peroxide as a radical generator was added over 1 hour while stirring the system while maintaining the internal temperature at 170°C. Thereafter, the mixture was allowed to react for 1 hour. After the reaction was completed, the obtained reaction product was poured into a large amount of acetone to precipitate the resin. The resin was further washed several times with acetone to remove unreacted monomers. Thereafter, the resin was dried under reduced pressure in a reduced pressure dryer to obtain a polyolefin resin (C1).

(Preparation of aqueous dispersion of polyolefin resin (C1))
A stirrer equipped with a airtight pressure-resistant 1 liter glass container equipped with a heater was prepared. Into the glass container of this stirrer, 60 g of polyolefin resin (C1), 45.0 g of ethylene glycol-n-butyl ether (boiling point 171°C), and 188.1 g of distilled water were charged, and the rotation speed of the stirring blade was set to 300 rpm. Stirred. After 10 minutes, the mixture was heated, and the system temperature was maintained at 140° C., and the mixture was further stirred for 60 minutes. Thereafter, the mixture was air-cooled to room temperature (approximately 25° C.) while stirring at a rotational speed of 300 rpm. The contents of the glass container were filtered under pressure (air pressure 0.2 MPa) through a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave) to obtain an aqueous dispersion of polyolefin resin (C1) (non-volatile component concentration 25% by mass). ) was obtained.

(Preparation of mold release agent (2))
100 parts by mass of an aqueous dispersion of polyolefin resin (C1) in terms of non-volatile components, and an aqueous polyvinyl alcohol solution (“JT-05” manufactured by Nippon Ace Vine & Poval Co., Ltd., saponification rate 94.5%, degree of polymerization 500, non-volatile components) A mold release agent (concentration: 8% by mass) was mixed with 300 parts by mass in terms of non-volatile components, and further water was added to adjust the final non-volatile component concentration to 6.0% by mass. 2) was obtained.

(Manufacture of support 2)
A PET film (“T60” (thickness: 38 μm) manufactured by Toray Industries, Inc.) was prepared as a supporting base material. A mold release agent (2) was coated on one side of this supporting base material using a gravure coater and dried to form a mold release layer with a thickness of 0.1 μm. Through the above operations, a support 2 including a support base material and a release layer containing no acrylic resin was obtained.

<Production Example 3: Production of resin varnish A1>
6 parts of bisphenol-type epoxy resin (“ZX1059” manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., epoxy equivalent: approximately 169 g/eq., 1:1 mixture of bisphenol A type and bisphenol F type), bixylenol type epoxy resin (manufactured by Mitsubishi Chemical Corporation “ YX4000HK", epoxy equivalent: about 185 g/eq.) 9 parts, biphenyl-type epoxy resin (Nippon Kayaku Co., Ltd. "NC3000L", epoxy equivalent: 288 g/eq.) 21 parts, and phenoxy resin (Mitsubishi Chemical Co., Ltd. "YX7553BH30") 10 parts of a 1:1 solution of cyclohexanone:methyl ethyl ketone (MEK) containing 30% by mass of non-volatile components was dissolved in a mixed solvent of 20 parts of solvent naphtha and 5 parts of cyclohexanone under heating with stirring to obtain a mixture. After cooling to room temperature, a triazine skeleton-containing cresol novolak curing agent (hydroxyl equivalent: 151 g/eq., "LA-3018-50P" manufactured by DIC, 2-methoxypropanol solution with 50% non-volatile components) 6 1 part, 20 parts of an active ester curing agent ("HPC-8000-65T" manufactured by DIC Corporation, a toluene solution containing 65% by mass of non-volatile components with a weight average molecular weight of about 2700 and an active group equivalent of about 223 g/eq.), imidazole curing 2 parts of accelerator (“1-benzyl-2-phenylimidazole” manufactured by Shikoku Kasei Co., Ltd., MEK solution containing 5% by mass of non-volatile components), flame retardant (“HCA-HQ” manufactured by Sankosha Co., Ltd., 10-(2,5-dihydroxy) 2 parts of phenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide (average particle size 2 μm) and 170 parts of an inorganic filler were mixed and uniformly dispersed with a high-speed rotating mixer. . Thereafter, this mixture was filtered through a cartridge filter ("SHP050" manufactured by ROKITECHNO) to prepare resin varnish A1. As an inorganic filler, spherical silica ("SOC2" manufactured by Admatex Co., Ltd., average particle size 0.5 μm, specific surface area 5.8 m ² /g) whose surface was treated with an aminosilane coupling agent ("KBM573" manufactured by Shin-Etsu Chemical Co., Ltd.) was used. ) was used.

<Production Example 4: Production of resin varnish A2>
30 parts of biphenyl type epoxy resin (epoxy equivalent: approx. 290 g/eq., "NC3000H" manufactured by Nippon Kayaku Co., Ltd.), 5 parts of naphthalene type tetrafunctional epoxy resin (epoxy equivalent: 162 g/eq., "HP-4700" manufactured by DIC Corporation) , 15 parts of liquid bisphenol A type epoxy resin (epoxy equivalent: 180 g/eq., "jER828EL" manufactured by Mitsubishi Chemical Corporation), and phenoxy resin (weight average molecular weight 35,000, "YX7553BH30" manufactured by Mitsubishi Chemical Corporation), methyl ethyl ketone with a non-volatile content of 30% by mass. (MEK) solution) was heated and dissolved in a mixed solvent of 8 parts of MEK and 8 parts of cyclohexanone with stirring to obtain a mixture. To this mixture, 32 parts of a triazine skeleton-containing phenol novolac curing agent (phenolic hydroxyl equivalent: approximately 124 g/eq., "LA-7054" manufactured by DIC Corporation, MEK solution containing 60% by mass of non-volatile components), an imidazole curing accelerator ( "1-Benzyl-2-phenylimidazole" manufactured by Shikoku Kasei Co., Ltd., 2 parts of MEK solution containing 5% by mass of non-volatile components, 160 parts of inorganic filler, polyvinyl butyral resin solution (weight average molecular weight 27000, glass transition temperature 105°C, Sekisui Co., Ltd.) Mix 2 parts of "KS-1" manufactured by Kagaku Kogyo Co., Ltd. (a mixed solution of 15% by mass of nonvolatile components and a 1:1 mass ratio of ethanol and toluene) and uniformly disperse with a high-speed rotating mixer to make resin varnish A2. Prepared. As an inorganic filler, spherical silica ("SOC2" manufactured by Admatex Co., Ltd., average particle size 0.5 μm, specific surface area 5.8 m ² /g) whose surface was treated with an aminosilane coupling agent ("KBM573" manufactured by Shin-Etsu Chemical Co., Ltd.) was used. ) was used.

<Production Example 5: Production of resin varnish B1>
Add 2 parts of an imidazole-based curing accelerator ("1-benzyl-2-phenylimidazole" manufactured by Shikoku Kasei Co., Ltd., MEK solution containing 5% by mass of non-volatile components) to a phosphorus-based curing accelerator ("Tetrabutylphosphonium decane" manufactured by Hokko Chemical Co., Ltd. Resin varnish B1 was prepared in the same manner as in Production Example 3, except that the amount was changed to 2 parts (acid acid, MEK solution containing 5% by mass of non-volatile components).

[Example 1]
(Manufacture of resin sheet)
Resin varnish A1 was uniformly applied to the release layer side surface of the support 1 obtained in Production Example 1 using a die coater, and dried at 80 ° C. to 120 ° C. (average 100 ° C.) for 6 minutes. A resin sheet comprising a supporting base material, a release layer, and a resin composition layer in this order was obtained. The thickness of the resin composition layer of the resin sheet was 40 μm.

(Lamination of resin sheet to inner layer circuit board)
Both sides of a glass cloth base epoxy resin double-sided copper-clad laminate (copper foil thickness 18 μm, substrate thickness 0.8 mm, “R1515A” manufactured by Panasonic Electric Works Co., Ltd.) were coated with an etching agent (“CZ8100” manufactured by MEC Corporation). The copper surface was roughened by immersion to obtain an inner layer circuit board. Resin sheets were laminated on both sides of this inner layer circuit board using a batch type vacuum pressure laminator (two-stage build-up laminator "CVP700" manufactured by Nichigo Morton Co., Ltd.). This lamination was performed so that the resin composition layer of the resin sheet was bonded to the inner layer circuit board. Further, this lamination was performed by reducing the pressure for 30 seconds to bring the atmospheric pressure to 13 hPa or less, and then press-bonding at 100° C. and a pressure of 0.74 MPa for 30 seconds. By the above lamination, a sample laminate including a support, a resin composition layer, an inner circuit board, a resin composition layer, and a support in this order was obtained.

(Curing of resin composition layer)
After laminating the resin composition layer and the inner layer circuit board, the sample laminate was placed in a nitrogen oven with the support still attached. After charging, the door was closed and nitrogen was circulated until the oxygen concentration in the oven reached 0.5%. After confirming that the oxygen concentration in the oven was 0.5%, the resin composition layer was thermally cured under the following curing conditions. Specifically, under the curing conditions of Example 1, the temperature inside the oven was raised from 30°C to 130°C at a rate of 10°C/min, then heat curing was proceeded at 130°C for 30 minutes, and then the temperature was increased to 10°C. The temperature was raised to 170° C./min, and then thermal curing was further advanced at 170° C. for 30 minutes. Thereafter, the temperature was lowered to 30°C at a rate of 5°C/min, and the sample laminate was taken out from the nitrogen oven. Since the resin composition layer was thermally cured to form an insulating layer, an evaluation sample including a support, an insulating layer, an inner circuit board, an insulating layer, and a support in this order was obtained. The thickness of the insulating layer on the inner layer circuit was 40 μm.

(Peeling of support)
The evaluation sample was cooled to room temperature (about 25°C), and then the support was peeled off. The peelability was good, and peeling of the support was achieved without damaging the support and the insulating layer. As a result of the peeling, a printed wiring board including an insulating layer and a support peeled off from the insulating layer were obtained.

[Example 2]
A resin sheet, an evaluation sample, and a printed wiring board were manufactured in the same manner as in Example 1, except that resin varnish A1 was changed to resin varnish A2. In the step of peeling off the support, the peelability was good, and peeling of the support was achieved without damaging the support and the insulating layer.

[Comparative example 1]
A resin sheet and an evaluation sample were produced in the same manner as in Example 1, except that the curing conditions in the step of thermally curing the resin composition layer were changed as follows. In the curing conditions of Comparative Example 1, after confirming that the oxygen concentration in the oven was 0.5%, the temperature inside the oven was raised from 30°C to 200°C at a rate of 10°C/min, and then at 200°C. Heat curing was allowed to proceed for 90 minutes. Thereafter, the temperature was lowered to 30°C at a rate of 5°C/min, and the sample laminate was taken out from the nitrogen oven to obtain an evaluation sample.

The evaluation sample was cooled to room temperature (approximately 25° C.), and then peeling of the support was attempted. However, the insulating layer and the support adhered to each other, making it difficult to separate them. Further, when the support was forcibly peeled off, the support was destroyed.

[Comparative example 2]
A resin sheet and an evaluation sample were manufactured in the same manner as in Comparative Example 1, except that resin varnish A1 was changed to resin varnish A2. The evaluation sample was cooled to room temperature (approximately 25° C.), and then peeling of the support was attempted. However, the insulating layer and the support adhered to each other, making it difficult to separate them. Further, when the support was forcibly peeled off, the support was destroyed.

[Reference example 1]
A resin sheet and an evaluation sample were manufactured in the same manner as in Comparative Example 1, except that resin varnish A1 was changed to resin varnish B. The evaluation sample was cooled to room temperature (about 25°C), and then the support was peeled off. The peelability was good, and peeling of the support was achieved without damaging the support and the insulating layer. As a result of the peeling, a printed wiring board including an insulating layer and a support peeled off from the insulating layer were obtained.

[Reference example 2]
A resin sheet and an evaluation sample were manufactured in the same manner as in Comparative Example 1, except that Support 1 was changed to Support 2. The evaluation sample was cooled to room temperature (about 25°C), and then the support was peeled off. The peelability was good, and peeling of the support was achieved without damaging the support and the insulating layer. As a result of the peeling, a printed wiring board including an insulating layer and a support peeled off from the insulating layer were obtained.

[Reference example 3]
A resin sheet and an evaluation sample were produced in the same manner as in Comparative Example 1, except that the support 1 was changed to a PET film ("E7004" manufactured by Toyobo Co., Ltd., thickness 38 μm) provided with a silicone release layer. The evaluation sample was cooled to room temperature (about 25°C), and then the support was peeled off. The peelability was good, and peeling of the support was achieved without damaging the support and the insulating layer. As a result of the peeling, a printed wiring board including an insulating layer and a support peeled off from the insulating layer were obtained.

[Reference example 4]
A resin sheet and evaluation sample were produced in the same manner as in Comparative Example 1, except that after the sample laminate was placed in a nitrogen oven, the resin composition layer was thermally cured in an air atmosphere without circulating nitrogen. did. The evaluation sample was cooled to room temperature (about 25°C), and then the support was peeled off. The peelability was good, and peeling of the support was achieved without damaging the support and the insulating layer. As a result of the peeling, a printed wiring board including an insulating layer and a support peeled off from the insulating layer were obtained.

[result]
The results of the above Examples, Comparative Examples, and Reference Examples are shown in the table below. The meanings of the abbreviations in the "Judgment" section of the table below are as follows.
"OK": The support could be peeled off without damaging the support and the insulating layer.
"NG": A peeling failure occurred in which the support or the insulating layer was destroyed.

[Consider]
From the results of Comparative Examples 1 and 2, it can be seen that conventionally, poor peeling occurred between the support and the resin composition layer. Furthermore, from the results of Reference Examples 1 to 4, the above-mentioned peeling failure is caused by the fact that the mold release agent contains a (meth)acrylic resin, the resin composition layer contains a resin composition containing an imidazole-based compound, and It can be seen that this is a unique problem that occurred when all of the following conditions were met: curing was performed in a nitrogen atmosphere. From Examples 1 and 2, it was confirmed that the above specific problems can be solved by the manufacturing method of the present invention.

Claims (7)

(I) A resin sheet comprising a support provided with a release layer and a resin composition layer formed on the release layer of the support is placed on the inner layer such that the resin composition layer is bonded to the inner layer substrate. The process of laminating it on the substrate,
(II) a step of thermosetting the resin composition layer in a nitrogen atmosphere; and (III) a step of peeling off the support;
A method for manufacturing a printed wiring board, the method comprising: in this order;
The release layer includes (meth)acrylic resin;
the resin composition layer includes a resin composition containing an imidazole compound;
Thermal curing of the resin composition layer includes, in this order, subjecting the resin composition layer to a heat treatment in which the resin composition layer is held at a temperature T1 and a heat treatment in which the resin composition layer is held at a temperature T2 higher than the temperature T1. A method for manufacturing printed wiring boards. The method for manufacturing a printed wiring board according to claim 1, wherein the resin composition contains a thermosetting resin. A claim in which the thermosetting resin includes one or more selected from the group consisting of epoxy resins, phenol resins, active ester resins, carbodiimide resins, acid anhydride resins, amine resins, benzoxazine resins, cyanate ester resins, and thiol resins. Item 2. The method for manufacturing a printed wiring board according to item 2. The method for manufacturing a printed wiring board according to any one of claims 1 to 3, wherein the temperature T2 is 150° C. or higher. The method for manufacturing a printed wiring board according to any one of claims 1 to 4, wherein the difference T2-T1 between temperature T1 and temperature T2 is 20° C. or more. The method for manufacturing a printed wiring board according to any one of claims 1 to 5, wherein temperature T1 is 50° C. or higher. According to any one of claims 1 to 6, wherein step (II) includes heating the resin composition layer to temperature T2 at a temperature increase rate of 0.5 ° C / min or more and 30 ° C / min or less. A method of manufacturing the printed wiring board described.