JP7276199B2 - Method for manufacturing printed wiring board - Google Patents

Description

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

2. Description of the Related Art As a method of manufacturing a printed wiring board, a manufacturing method by a build-up method in which insulating layers and conductor layers are alternately stacked is known. In the build-up manufacturing method, generally, a resin composition layer containing a resin composition is cured to form an insulating layer. Formation of such an insulating layer may be carried out using a resin sheet comprising a support and a resin composition layer, as described in Patent Document 1.

JP 2017-183411 A

In the method of manufacturing a printed wiring board, the insulating layer may be perforated. For example, holes such as via holes are sometimes formed in the insulating layer for the purpose of connecting between conductor layers insulated by the insulating layer. When such a drilling process is performed, a resin residue called "smear" may be formed in the hole. Therefore, in many cases, desmearing is performed to remove smears with an oxidizing agent after drilling. In the desmearing process, smears are removed by bringing an oxidizing agent into contact with the hole-formed portions of the insulating layer.

In the desmear process, the oxidizing agent may come into contact with portions other than the holes in the insulating layer. The surface of the insulating layer that is in contact with the oxidizing agent is generally roughened by the oxidizing agent, resulting in a rough surface shape. In particular, when conditions that promote oxidation are employed in order to efficiently remove smears, the surface of the insulating layer tends to increase in roughness because roughening progresses greatly.

In recent years, there has been an increasing demand for finer wiring on printed wiring boards. However, it is difficult to form fine wiring as a conductor layer on the surface of the insulating layer having a large degree of roughness. On the other hand, if the progress of roughening with an oxidizing agent is reduced in order to reduce the roughness of the surface of the insulating layer, smear may not be sufficiently removed. Thus, conventionally, it has been difficult to achieve both effective smear removal and wiring miniaturization. Therefore, there is a demand for the development of a technique capable of improving smear removability and reducing the surface roughness of the insulating layer at the same time.

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 achieve both improvement in smear removability and reduction in surface roughness of an insulating layer.

The inventors have made extensive studies to solve the above problems. As a result, the present inventors prepared a resin sheet comprising a support, a release layer, and a resin composition layer in this order; laminating the resin composition layer and the substrate; Curing; peeling off the support to obtain an intermediate multilayer body comprising at least part of a substrate, a resin composition layer and a release layer in this order; and a release layer side surface of the intermediate multilayer body The inventors have found that the above problems can be solved by a production method comprising, in this order, contacting an oxidizing agent with and completed the present invention.
That is, the present invention includes the following.

[1] A first step of preparing a resin sheet comprising a support, a release layer, and a resin composition layer in this order;
A second step of laminating the resin composition layer and the substrate;
a third step of curing the resin composition layer;
a fourth step of peeling off the support to obtain an intermediate multilayer body comprising the substrate, the resin composition layer, and at least part of the release layer in this order;
and a fifth step of bringing an oxidizing agent into contact with the release layer-side surface of the intermediate multilayer body, in this order.
[2] The method for producing a printed wiring board according to [1], which includes a sixth step of forming holes in the resin composition layer after the third step and before the fifth step.
[3] The method for producing a printed wiring board according to [1] or [2], wherein part of the release layer is attached to the support that has been peeled off in the fourth step.
[4] The method for producing a printed wiring board according to any one of [1] to [3], wherein in the fourth step, the release layer is destroyed inside the release layer. .
[5] The printed wiring board according to any one of [1] to [4], wherein the release layer-side surface of the intermediate multilayer body has a water contact angle of 75° or more and 110° or less. Production method.
[6] The water contact angle of the release layer side surface of the intermediate multilayer body and the water contact angle of the release layer side surface of the peeled body including the support peeled in the fourth step. , is 17° or less, the printed wiring board manufacturing method according to any one of [1] to [5].
[7] The method for producing a printed wiring board according to any one of [1] to [6], including a seventh step of forming a conductor layer after the fifth step.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the printed wiring board which can improve smear removability and the low roughness of the surface of an insulating layer can be provided.

FIG. 1 is a cross-sectional view schematically showing a resin sheet prepared in the first step of a printed wiring board manufacturing method according to one embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing a resin sheet and a substrate in the second step of the printed wiring board manufacturing method according to one embodiment of the present invention. FIG. 3 is a cross-sectional view schematically showing a resin sheet and a substrate in the third step of the printed wiring board manufacturing method according to one embodiment of the present invention. FIG. 4 is a cross-sectional view schematically showing a resin sheet and a substrate in which holes are formed in the sixth step of the printed wiring board manufacturing method according to one embodiment of the present invention. FIG. 5 is a cross-sectional view schematically showing an intermediate multilayer body and a stripped body obtained in the fourth step of the printed wiring board manufacturing method according to one embodiment of the present invention. FIG. 6 is a cross-sectional view schematically showing a printed wiring board obtained by subjecting the intermediate multilayer body to oxidation treatment in the fifth step of the printed wiring board manufacturing method according to one embodiment of the present invention. FIG. 7 is a cross-sectional view schematically showing a printed wiring board on which a conductor layer is formed in the seventh step of the printed wiring board manufacturing method according to the first embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to embodiments and examples. However, the present invention is not limited to the following embodiments and examples, and can be arbitrarily modified without departing from the scope of the claims of the present invention and their equivalents.

[1. Outline of printed wiring board manufacturing method]
A method for manufacturing a printed wiring board according to an embodiment of the present invention comprises:
A first step of preparing a resin sheet comprising a support, a release layer, and a resin composition layer in this order;
A second step of laminating the resin composition layer and the substrate;
a third step of curing the resin composition layer;
a fourth step of peeling off the support to obtain an intermediate multilayer body comprising a substrate, a resin composition layer, and at least part of a release layer in this order;
a fifth step of bringing an oxidizing agent into contact with the release layer side surface of the intermediate multilayer body;
in that order.

In the following description, the resin composition layer after being cured in the third step may be referred to as an "insulating layer" as appropriate. In addition, the surface of the intermediate multilayer body on the release layer side may be appropriately referred to as the "release surface" of the intermediate multilayer body. The release surface of the intermediate multilayer body corresponds to the surface on which the support was provided before the fourth step. Therefore, the intermediate multilayer body includes the substrate, the resin composition layer, and the release surface in this order in the thickness direction.

The method for manufacturing a printed wiring board according to one embodiment of the present invention may further include an arbitrary step in combination with the first to fifth steps. The method for manufacturing a printed wiring board may include, for example, a sixth step of forming holes in the insulating layer after the third step and before the fifth step. Moreover, the method for manufacturing a printed wiring board may include, for example, a seventh step of forming a conductor layer after the fifth step.

According to the printed wiring board manufacturing method described above, in the fifth step, the smear can be effectively removed by the oxidizing agent, and the release surface of the intermediate multilayer body is excessively roughened by contact with the oxidizing agent. progression can be suppressed. Therefore, according to the printed wiring board manufacturing method described above, it is possible to achieve both an improvement in smear removability and a reduction in surface roughness of the insulating layer.

[2. First step: preparation of resin sheet]
In the first step, a resin sheet is prepared. FIG. 1 is a cross-sectional view schematically showing a resin sheet 100 prepared in the first step of the printed wiring board manufacturing method according to one embodiment of the present invention. As shown in FIG. 1, the resin sheet 100 includes a support 110, a release layer 120 and a resin composition layer 130 in this order in the thickness direction. Generally, the support 110 and the release layer 120 are in direct contact, and the release layer 120 and the resin composition layer 130 are in direct contact. The term "directly" in which two members are in contact means that there is no other layer between them.

[2.1. Support]
A plate-like or film-like member can be used as the support. Examples of such supports include films made of plastic materials, metal foils, and release papers. A film formed of a plastic material may hereinafter be referred to as a "plastic film" as appropriate. Among these, plastic films and metal foils are preferred.

Examples of plastic materials that make up the plastic film include polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter sometimes abbreviated as "PEN"); hereinafter sometimes abbreviated as "PC"); acrylic polymers such as polymethyl methacrylate (hereinafter sometimes abbreviated as "PMMA"); cyclic polyolefins; triacetyl cellulose (hereinafter sometimes abbreviated as "TAC") polyether sulfide (hereinafter sometimes abbreviated as “PES”); polyether ketone; polyimide; One type of these materials may be used alone, or two or more types may be used in combination. Among them, polyethylene terephthalate and polyethylene naphthalate are preferable, and inexpensive polyethylene terephthalate is particularly preferable.

The plastic film may contain particles capable of forming minute protrusions that can impart lubricity to the extent that the smoothness of the film surface is not affected.

When a metal foil is used as the support, examples of the metal foil include copper foil and aluminum foil, with copper foil being preferred. As the copper foil, a foil made of a single metal of copper may be used, and 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 surface of the support may be subjected to a treatment such as matte treatment, corona treatment, antistatic treatment, or the like.

The thickness of the support 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.

[2.2. release layer]
The release layer is made of a release agent. Due to the action of the release agent, the support can be peeled off smoothly. Specifically, the support provided on the resin composition layer via the release layer can be peeled off with less force than the support provided directly on the resin composition layer. Here, "directly" in which the support is provided on the resin composition layer means that there is no other layer between the resin composition layer and the support.

As the release agent contained in the release layer, a release agent that allows at least part of the release layer to remain on the resin composition layer after the support is peeled off in the fourth step can be used. Generally, release agents containing suitable resins are used. Examples of release agents include polyolefin resin release agents, urethane resin release agents, alkyd resin release agents, and silicone resin release agents. One release agent may be used alone, or two or more release agents may be used in combination. Among them, a polyolefin resin release agent is preferable.

As the polyolefin resin release agent, one containing a combination of an acid-modified polyolefin resin, a cross-linking agent, and polyvinyl alcohol having a specific saponification rate is preferred. When this polyolefin resin-based release agent is used, the release layer can be separated by causing cohesive failure, so that a residual release layer, which will be described later, can be obtained smoothly. Therefore, it is possible to remarkably obtain the effects of improving the smear removability and reducing the surface roughness of the insulating layer.

The olefin component constituting the acid-modified polyolefin resin that can be contained in the preferred polyolefin resin release agent preferably contains at least one selected from the group consisting of ethylene, propylene and butene. Among them, propylene is preferable from the viewpoint of releasability. From the viewpoint of further improving releasability, the amount of propylene in 100% by mass of the olefin component is preferably 50% by mass or more, more preferably 80% by mass or more, still more preferably 95% by mass or more, and particularly 99% by mass or more. preferable.

The acid-modified component constituting the acid-modified polyolefin resin is preferably an unsaturated carboxylic acid component. Examples of unsaturated carboxylic acid components include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid and crotonic acid; esters and half amides; Among them, acrylic acid, methacrylic acid, maleic acid and maleic anhydride are preferred from the viewpoint of stably dispersing the resin when preparing the liquid composition for forming the release layer, and acrylic acid, methacrylic acid and maleic anhydride are preferred. Acids are particularly preferred.

The amount of the acid-modified component in the acid-modified polyolefin resin is preferably 1% by mass to 10% by mass, more preferably 2% by mass to 9% by mass, based on 100% by mass of the acid-modified polyolefin resin. When the amount of the acid-modified component is above the lower limit of the above range, the adhesion between the support and the release layer can be enhanced. In addition, it becomes easy to stably disperse the resin when preparing the liquid composition for forming the release layer. On the other hand, when the amount of the acid-modified component is equal to or less than the upper limit of the above range, the releasability of the release layer can be enhanced.

From the viewpoint of improving the adhesion between the support and the release layer, the acid-modified polyolefin resin may contain an ethylenically unsaturated component containing an oxygen atom in the side chain. Ethylenically unsaturated components containing oxygen atoms in side chains include, for example, esters of (meth)acrylic acid and alcohols having 1 to 30 carbon atoms. Among them, esters of (meth)acrylic acid and alcohols having 1 to 20 carbon atoms are preferred because of their easy availability. Specific examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, (meth) ) decyl acrylate, lauryl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate and the like. Among them, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, hexyl acrylate, and octyl acrylate are more preferable from the viewpoint of adhesion to the support, and ethyl acrylate and acrylic acid. Butyl is more preferred, and ethyl acrylate is particularly preferred. The term "(meth)acrylic acid" includes acrylic acid, methacrylic acid and combinations thereof.

The amount of the ethylenically unsaturated component containing an oxygen atom in the side chain in the acid-modified polyolefin resin is preferably 1% by mass to 40% by mass, and 2% by mass to 35% by mass, based on 100% by mass of the acid-modified polyolefin resin. %, more preferably 3% by mass to 30% by mass, and particularly preferably 6% by mass to 18% by mass. When the amount of the ethylenically unsaturated component containing an oxygen atom in the side chain is above the lower limit of the above range, the adhesion between the support and the release layer can be enhanced. On the other hand, when the amount of the ethylenically unsaturated component containing an oxygen atom in the side chain is equal to or less than the upper limit of the above range, the releasability of the release layer can be enhanced.

Each component constituting the acid-modified polyolefin resin is usually copolymerized in the acid-modified polyolefin resin. Examples of the state of copolymerization include random copolymerization, block copolymerization, and graft copolymerization (graft modification).

The melting point of the acid-modified polyolefin resin is preferably 80°C to 200°C, more preferably 90°C to 150°C. When the melting point of the acid-modified polyolefin resin is at least the lower limit of the above range, the releasability of the release layer can be enhanced. On the other hand, when the melting point of the acid-modified polyolefin resin is equal to or lower than the upper limit of the above range, the release layer can be easily formed.

As a cross-linking agent that may be contained in a preferable polyolefin resin release agent, a compound containing a plurality of functional groups capable of reacting with a carboxyl group in the molecule is preferable. Preferred cross-linking agents include, for example, polyfunctional epoxy compounds; polyfunctional isocyanate compounds; polyfunctional aziridine compounds; carbodiimide group-containing compounds; oxazoline group-containing compounds; etc. Among them, polyfunctional isocyanate compounds, melamine compounds, urea compounds, polyfunctional epoxy compounds, carbodiimide group-containing compounds, and oxazoline group-containing compounds are preferred, carbodiimide group-containing compounds and oxazoline group-containing compounds are more preferred, and oxazoline group-containing compounds are preferred. Especially preferred. By using the oxazoline group-containing compound, the adhesion between the support and the release layer can be effectively enhanced, and the releasability of the release layer can be effectively enhanced.

Examples of polyfunctional epoxy compounds include polyepoxy compounds and diepoxy compounds. Examples of polyepoxy compounds include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris(2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, trimethylolpropane. Polyglycidyl ethers are mentioned. Examples of diepoxy compounds include neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcinol diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether. glycidyl ether, polytetramethylene glycol diglycidyl ether;

Polyfunctional isocyanate compounds include, for example, tolylene diisocyanate, diphenylmethane-4,4′-diisocyanate, m-xylylene diisocyanate, hexamethylene-1,6-diisocyanate, 1,6-diisocyanatohexane, tolylene diisocyanate and hexanetriol. Adducts, adducts of tolylene diisocyanate and trimethylolpropane, polyol-modified diphenylmethane-4,4'-diisocyanate, carbodiimide-modified diphenylmethane-4,4'-diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, 3,3' -bitrylene-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, metaphenylene diisocyanate and the like. Also, a blocked isocyanate compound obtained by blocking the isocyanate groups of these polyfunctional isocyanate compounds with a suitable compound may be used as a cross-linking agent. Compounds that can be used to block isocyanate groups include, for example, bisulfite compounds, phenol compounds containing sulfonic acid groups, alcohol compounds, lactam compounds, oxime compounds and active methylene compounds. Examples of commercially available polyfunctional isocyanate compounds include "Basonate HW-100" manufactured by BASF.

Examples of polyfunctional aziridine compounds include N,N'-hexamethylene-1,6-bis-(1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, and the like.

Examples of carbodiimide group-containing compounds include compounds having one or more carbodiimide groups in the molecule. A carbodiimide compound can form an ester with two carboxyl groups in an acid-modified portion of an acid-modified polyolefin resin in one carbodiimide portion to achieve cross-linking. Specific examples of carbodiimide group-containing compounds include p-phenylene-bis(2,6-xylylcarbodiimide), tetramethylene-bis(t-butylcarbodiimide), cyclohexane-1,4-bis(methylene-t-butylcarbodiimide ), a compound having a carbodiimide group; polycarbodiimide, which is a polymer having a carbodiimide group; and the like. Among them, polycarbodiimide is preferable because of ease of handling. Commercially available products of polycarbodiimide include Carbodilite series manufactured by Nisshinbo.

Examples of oxazoline group-containing compounds include compounds having two or more oxazoline groups in the molecule. The oxazoline compound can form an amide ester with one carboxyl group in the acid-modified portion of the acid-modified polyolefin resin in each of the two oxazoline moieties to achieve cross-linking. Such an oxazoline group-containing compound can be produced by homopolymerization of an addition polymerizable oxazoline group-containing monomer; copolymerization of an addition polymerizable oxazoline group-containing monomer and any other monomer; Examples of addition polymerizable oxazoline group-containing monomers include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2 -oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline and the like. Among these, 2-isopropenyl-2-oxazoline is suitable because it is easily available industrially. Examples of optional monomers include alkyl acrylates, alkyl methacrylates (alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2- ethylhexyl group, cyclohexyl group) and other (meth)acrylic acid ester compounds; salts, tertiary amine salts, etc.); unsaturated nitrile compounds such as acrylonitrile and methacrylonitrile; acrylamide, methacrylamide, N-alkylacrylamide, N-alkylmethacrylamide, N,N-dialkyl Acrylamide, N,N-dialkyl methacrylate (alkyl groups include, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group etc.); vinyl ester compounds such as vinyl acetate and vinyl propionate; vinyl ether compounds such as methyl vinyl ether and ethyl vinyl ether; α-olefin compounds such as ethylene and propylene; halogen-containing α,β-unsaturated aliphatic monomer compounds such as; α,β-unsaturated aromatic monomers such as styrene and α-methylstyrene; Among them, an oxazoline group-containing polymer is preferable because of ease of handling. Examples of commercially available oxazoline group-containing polymers include Epocross series manufactured by Nippon Shokubai Co., Ltd.

Phenolic resins include, for example, phenol; alkylphenols such as bisphenol A, pt-butylphenol, octylphenol and p-cumylphenol; p-phenylphenol; cresol; type phenolic resin.

Urea compounds include, for example, dimethylolurea, dimethylolethyleneurea, dimethylolpropyleneurea, tetramethylolacetyleneurea, 4-methoxy-5-dimethylpropyleneurea dimethylol.

Examples of melamine resins include compounds having in one molecule at least one functional group selected from the group consisting of an imino group, a methylol group and an alkoxymethyl group. Examples of the alkoxymethyl group include methoxymethyl group and butoxymethyl group. Specific examples of melamine resins include imino group-type methylated melamine resins, methylol group-type melamine resins, methylol group-type methylated melamine resins, and completely alkyl-type methylated melamine resins. Among them, a methylolated melamine resin is particularly preferred. Further, it is preferable to use an acidic catalyst such as p-toluenesulfonic acid to accelerate the thermosetting of the melamine resin.

Benzoguanamine resins include, for example, trimethylolbenzoguanamine, hexamethylolbenzoguanamine, trismethoxymethylbenzoguanamine, hexakismethoxymethylbenzoguanamine, and the like.

By using a cross-linking agent, the components contained in the release layer are cross-linked to improve the releasability. Crosslinking can also improve the cohesive strength of the release layer, making it easier for cohesive failure to occur. Furthermore, the water resistance of the release layer can be improved.

The amount of the cross-linking agent is preferably 1 part by mass or more, preferably 2 parts by mass or more, preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and particularly preferably, with respect to 100 parts by mass of the acid-modified polyolefin resin. is 10 parts by mass or less. When the amount of the cross-linking agent is at least the lower limit of the above range, the cohesive force of the release layer can be increased, so that the adhesion between the support and the release layer can be enhanced, and the releasability of the release layer can be enhanced. can On the other hand, when the amount of the cross-linking agent is equal to or less than the upper limit of the above range, the releasability of the release layer is enhanced, or the thickening of the liquid composition used for producing the release layer is suppressed to improve stability. can be enhanced.

Polyvinyl alcohol, which may be included in preferred polyolefin resin release agents, has a saponification rate within a specific range. Specifically, the saponification rate of polyvinyl alcohol is preferably 80% or more, more preferably 85% or more, particularly preferably 90% or more, preferably 99% or less, more preferably less than 98%, and still more preferably. is less than 96%, particularly preferably less than 95%. When the saponification rate of polyvinyl alcohol is equal to or higher than the lower limit of the above range, the liquid composition used for producing the release layer can be stabilized, and the productivity of the release layer can be enhanced. Further, when the saponification rate of polyvinyl alcohol is equal to or lower than the upper limit of the above range, it is possible to suppress the generation of fine non-planar shapes having a height of several tens of nm to several hundreds of nm on the surface of the release layer. Therefore, the surface shape of the resin composition layer can be made smooth. Furthermore, it is possible to suppress warping of the release layer in a high humidity environment, and to suppress separation electrification in a low humidity environment.

When the preferred polyolefin resin release agent is used, the release layer is usually produced using an aqueous solvent. Therefore, from the viewpoint of ease of mixing with an aqueous solvent, the polyvinyl alcohol is preferably water-soluble.

A commercial thing can be used as polyvinyl alcohol. Examples of polyvinyl alcohol include "JP-15", "JT-05", "JL-05E", "JM-33", and "JM-17" of "J-Poval" manufactured by Japan Vinyl Acetate & Poval Co., Ltd. , "JF-05", "JF-10", "PVA-CST", "PVA-624", "PVA-203", "PVA-220", "PVA-405" of "Kuraray Poval" manufactured by Kuraray Co., Ltd. is mentioned.

The amount of polyvinyl alcohol is preferably 10 parts by mass or more, more preferably 100 parts by mass or more, still more preferably 210 parts by mass or more, and particularly preferably 300 parts by mass or more, based on 100 parts by mass of the acid-modified polyolefin resin. It is preferably 1000 parts by mass or less, more preferably 800 parts by mass or less, and particularly preferably 600 parts by mass or less. When the amount of polyvinyl alcohol is at least the lower limit of the above range, the releasability of the release layer can be effectively improved. On the other hand, when the amount of polyvinyl alcohol is equal to or less than the upper limit of the above range, the viscosity of the liquid composition for forming the release layer is reduced, and the non-planar shape is generated on the surface of the release layer. can be suppressed.

A preferred polyolefin resin release agent may contain a lubricant. Lubricants such as calcium carbonate, magnesium carbonate, calcium oxide, zinc oxide, magnesium oxide, silicon oxide, sodium silicate, aluminum hydroxide, iron oxide, zirconium oxide, barium sulfate, titanium oxide, tin oxide, antimony trioxide, Inorganic particles such as carbon black and molybdenum disulfide; Organic particles such as acrylic crosslinked polymers, styrene crosslinked polymers, silicone resins, fluororesins, benzoguanamine resins, phenolic resins, nylon resins, and polyethylene waxes; surfactants; is mentioned.

When a release layer is formed using a preferred polyolefin resin-based release agent, a layer of a liquid composition containing the release agent and a solvent is usually formed on a support, dried as necessary, and dried. Stretching and heat treatment are performed. At this time, it is preferable to use an aqueous solvent as the solvent. International Publication No. 2018/056276 can be referred to for a release layer using such a preferable polyolefin resin-based release agent.

The thickness of the release layer is not particularly limited, but is preferably 0.01 μm or more, more preferably 0.05 μm or more, and preferably 1.00 μm or less, more preferably 0.50 μm or less. When the thickness of the release layer is at least the lower limit of the above range, the release layer can be smoothly separated inside by peeling off the support in the fourth step. Further, when the thickness of the release layer is equal to or less than the upper limit of the above range, the thickness of the release layer on the release surface of the intermediate multilayer body obtained in the fourth step can be reduced. It is possible to suppress the release layer from remaining after the process.

The thickness of the release layer can be measured by a curve fitting method using "Optical Nano Gauge C12562" manufactured by Hamamatsu Photonics.

[2.3. Resin composition layer]
The resin composition layer is made of a curable resin composition. As the resin composition contained in the resin composition layer, a thermosetting resin composition is usually used. Therefore, the resin composition usually contains a thermosetting resin.

The type of thermosetting resin can be appropriately selected according to the properties required for the insulating layer of the printed wiring board. In particular, as the thermosetting resin, it is preferable to use a combination of an epoxy resin and a curing agent capable of reacting with the epoxy resin.

Examples of epoxy resins include bixylenol type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, Naphthol novolak type epoxy resin, phenol novolak type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, glycidylamine type epoxy resin, glycidyl ester type epoxy resin, cresol novolac type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin, epoxy resin having a butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, spiro ring-containing epoxy resin, cyclohexane type epoxy resin, cyclohexane dimethanol type Epoxy resin, naphthylene ether type epoxy resin, trimethylol type epoxy resin, tetraphenylethane 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 resin composition preferably contains, as an epoxy resin, an epoxy resin having two or more epoxy groups in one molecule. The ratio of the epoxy resin having two or more epoxy groups in one molecule is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass with respect to 100% by mass of the non-volatile component of the epoxy resin. % or more.

Epoxy resins include liquid epoxy resins at a temperature of 20° C. (hereinafter sometimes referred to as “liquid epoxy resins”) and solid epoxy resins at a temperature of 20° C. (hereinafter sometimes referred to as “solid epoxy resins”). ). The resin composition may contain only a liquid epoxy resin or only a solid epoxy resin, but preferably contains a combination of a liquid epoxy resin and a solid epoxy resin. By using the liquid epoxy resin and the solid epoxy resin in combination, the flexibility of the resin composition can be improved, and the breaking strength of the cured product of the resin composition can be improved.

The liquid epoxy resin is preferably a liquid epoxy resin having two or more epoxy groups per molecule, more preferably an aromatic liquid epoxy resin having two or more epoxy groups per molecule. Here, the “aromatic” epoxy resin means an epoxy resin having an aromatic ring in its molecule.

Examples of 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, glycidyl amine type epoxy resin, phenol novolac type epoxy resin, and an ester skeleton. An alicyclic epoxy resin, a cyclohexane type epoxy resin, a cyclohexanedimethanol type epoxy resin, a glycidylamine type epoxy resin, and an epoxy resin having a butadiene structure are preferred. A liquid epoxy resin may be used individually by 1 type, and may be used in combination of 2 or more types. Among them, bisphenol A type epoxy resin, bisphenol F type epoxy resin and cyclohexane type epoxy resin are more preferable, and bisphenol A type epoxy resin and bisphenol F type epoxy resin are particularly preferable.

Specific examples of liquid epoxy resins include "HP4032", "HP4032D", and "HP4032SS" (naphthalene-type epoxy resins) manufactured by DIC; 828EL" (bisphenol A type epoxy resin); Mitsubishi Chemical Corporation "jER807", "1750" (bisphenol F type epoxy resin); Mitsubishi Chemical Corporation "jER152" (phenol novolac type epoxy resin); Mitsubishi Chemical Corporation "630", "630LSD" (glycidylamine type epoxy resin); Nippon Steel & Sumikin Chemical Co., Ltd. "ZX1059" (mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin); Nagase ChemteX Co., Ltd. "EX -721" (glycidyl ester type epoxy resin); Daicel's "Celoxide 2021P" (alicyclic epoxy resin having an ester skeleton); Daicel's "PB-3600" (epoxy resin having a butadiene structure); Nippon Steel "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane type epoxy resin) manufactured by Sumikin Chemical Co., Ltd., and the like can be mentioned.

The solid epoxy resin is preferably a solid epoxy resin having 3 or more epoxy groups per molecule, more preferably an aromatic solid epoxy resin having 3 or more epoxy groups per molecule.

Solid epoxy resins include bixylenol type epoxy resin, naphthalene type epoxy resin, naphthalene type tetrafunctional epoxy resin, cresol novolak type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol type epoxy resin, biphenyl type epoxy resin, naphthylene ether type epoxy resin, anthracene type epoxy resin, bisphenol A type epoxy resin, bisphenol AF type epoxy resin, and tetraphenylethane type epoxy resin. Solid epoxy resins may be used singly or in combination of two or more. Among them, bixylenol-type epoxy resins, naphthalene-type tetrafunctional epoxy resins, and biphenyl-type epoxy resins are more preferable.

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 novolac type epoxy resin) manufactured by DIC Corporation; "N-695" (cresol novolak type epoxy resin) manufactured by DIC Corporation; "HP-7200", "HP-7200HH", "HP -7200H" (dicyclopentadiene type epoxy resin); DIC's "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000" ( Naphthylene ether type epoxy resin); Nippon Kayaku Co., Ltd. "EPPN-502H" (trisphenol type epoxy resin); Nippon Kayaku Co., Ltd. "NC7000L" (naphthol novolac type epoxy resin); "NC3000H", "NC3000", "NC3000L", "NC3100" (biphenyl type epoxy resin); Nippon Steel & Sumikin Chemical Co., Ltd. "ESN475V" (naphthalene type epoxy resin); Nippon Steel & Sumikin Chemical Co., Ltd. "ESN485" (naphthol novolac type epoxy resin); "YX4000" and "YL6121" (biphenyl type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX4000H" and "YX4000HK" (bixylenol type epoxy resin) manufactured by Mitsubishi Chemical Corporation; YX8800" (anthracene type epoxy resin); "PG-100" and "CG-500" manufactured by Osaka Gas Chemicals; "YL7760" and "YX7760" manufactured by Mitsubishi Chemical Corporation (bisphenol AF type epoxy resin); Mitsubishi Chemical Corporation "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER1010" (solid bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER1031S" (tetraphenylethane type epoxy resin) manufactured by Mitsubishi Chemical Corporation. .

When a liquid epoxy resin and a solid epoxy resin are used in combination, the ratio by mass (liquid epoxy resin:solid epoxy resin) is preferably 1:1 to 1:20, more preferably 1:1. 1.5 to 1:15, particularly preferably 1:2 to 1:13. When the amount ratio of the liquid epoxy resin and the solid epoxy resin is in such a range, the resin composition layer can have appropriate adhesiveness and sufficient flexibility, so that handleability can be improved. Furthermore, it is usually possible to obtain an insulating layer with sufficient breaking strength.

The epoxy equivalent of the epoxy resin is preferably 50 g/eq. ~5000g/eq. , more preferably 50 g/eq. ~3000g/eq. , more preferably 80 g/eq. ~2000 g/eq. , even more preferably 110 g/eq. ~1000g/eq. is. When the epoxy equivalent is within this range, the crosslink density of the cured product of the resin composition is sufficient, and an insulating layer with a small surface roughness can be obtained. Epoxy equivalent weight is the mass of resin containing one equivalent of epoxy groups. This epoxy equivalent can be measured according to JIS K7236.

The weight average molecular weight (Mw) of the epoxy resin is preferably 100-5000, more preferably 250-3000, still more preferably 400-1500.

The weight average molecular weight of the resin can be measured as a polystyrene-equivalent value by a gel permeation chromatography (GPC) method. Specifically, the weight-average molecular weight is measured using LC-9A/RID-6A manufactured by Shimadzu Corporation as a measuring device, Shodex K-800P/K-804L/K-804L manufactured by Showa Denko Co., Ltd. as a column, and chloroform as a mobile phase. etc., the column temperature is measured at 40° C., and it can be calculated using a standard polystyrene calibration curve.

From the viewpoint of obtaining an insulating layer exhibiting good mechanical strength and insulation reliability, the amount of the epoxy resin in the resin composition is preferably 1% by mass or more, or more, relative to 100% by mass of the non-volatile components in the resin composition. It is preferably 5% by mass or more, more preferably 10% by mass or more, preferably 60% by mass or less, more preferably 50% by mass or less, and particularly preferably 40% by mass or less.

Examples of curing agents include active ester curing agents, phenol curing agents, naphthol curing agents, benzoxazine curing agents, cyanate ester curing agents, carbodiimide curing agents, amine curing agents, and acid anhydride curing agents. agents and the like. One type of curing agent may be used alone, or two or more types may be used in combination.

A compound having one or more active ester groups in one molecule can be used as the active ester curing agent. Among them, active ester curing agents include phenol esters, thiophenol esters, N-hydroxyamine esters, esters of heterocyclic hydroxy compounds, and the like, and have two or more ester groups per molecule with high reaction activity. Preferred are compounds having The active ester curing agent is preferably obtained by a condensation reaction between a carboxylic acid compound and/or a thiocarboxylic acid compound and a hydroxy compound and/or a thiol compound. In particular, from the viewpoint of improving heat resistance, an active ester curing agent obtained from a carboxylic acid compound and a hydroxy compound is preferred, and an active ester curing agent obtained from a carboxylic acid compound and a phenol compound and/or a naphthol compound is more preferred. .

Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid.

Examples of phenol compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, 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, phloroglucine, Benzenetriol, dicyclopentadiene-type diphenol compound, phenol novolak, and the like. Here, the term "dicyclopentadiene-type diphenol compound" refers to a diphenol compound obtained by condensing one molecule of dicyclopentadiene with two molecules of phenol.

Preferred specific examples of the active ester curing agent include an active ester curing agent containing a dicyclopentadiene type diphenol structure, an active ester curing agent containing a naphthalene structure, an active ester curing agent containing an acetylated phenol novolac, Examples include active ester curing agents containing benzoylated phenol novolacs. Among them, an active ester curing agent containing a naphthalene structure and an active ester curing agent containing a dicyclopentadiene type diphenol structure are more preferable. "Dicyclopentadiene-type diphenol structure" represents a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

Commercially available active ester curing agents include "EXB9451", "EXB9460", "EXB9460S", "HPC-8000" and "HPC-8000H" as active ester curing agents containing a dicyclopentadiene type diphenol structure. , "HPC-8000-65T", "HPC-8000H-65TM", "EXB-8000L", "EXB-8000L-65TM", "EXB-8150-65T" (manufactured by DIC); active ester containing a naphthalene structure "EXB9416-70BK", "EXB-8150-65T", "EXB-8100L-65T", "EXB-8150L-65T" (manufactured by DIC) as system curing agents; active ester curing agents containing acetylated phenol novolak "DC808" (manufactured by Mitsubishi Chemical Corporation) as a curing agent; "YLH1026" (manufactured by Mitsubishi Chemical Corporation) as an active ester curing agent containing a benzoylated phenol novolac; "DC808" as an active ester curing agent that is an acetylated phenol novolac " (manufactured by Mitsubishi Chemical Corporation); "YLH1026" (manufactured by Mitsubishi Chemical Corporation), "YLH1030" (manufactured by Mitsubishi Chemical Corporation), and "YLH1048" (manufactured by Mitsubishi Chemical Corporation) as active ester curing agents that are benzoyl compounds of phenol novolak. ; and the like.

From the viewpoint of heat resistance and water resistance, the phenol-based curing agent and naphthol-based curing agent preferably have a novolak structure. From the viewpoint of adhesion between the conductor layer and the insulating layer, a nitrogen-containing phenol-based curing agent is preferable, and a triazine skeleton-containing phenol-based curing agent is more preferable.

Specific examples of phenol-based curing agents and naphthol-based curing agents include "MEH-7700", "MEH-7810", and "MEH-7851" manufactured by Meiwa Kasei; "NHN" manufactured by Nippon Kayaku; "CBN", "GPH"; "SN170", "SN180", "SN190", "SN475", "SN485", "SN495", "SN-495V", "SN375", "SN-" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. 395"; "TD-2090", "LA-7052", "LA-7054", "LA-1356", "LA-3018-50P", "EXB-9500" manufactured by DIC;

Specific examples of benzoxazine-based curing agents include "JBZ-OP100D" and "ODA-BOZ" manufactured by JFE Chemical Co., Ltd.; "HFB2006M" manufactured by Showa Polymer Co., Ltd.; "Fa" can be mentioned.

Examples of cyanate ester curing agents include bisphenol A dicyanate, polyphenolcyanate, oligo(3-methylene-1,5-phenylenecyanate), 4,4′-methylenebis(2,6-dimethylphenylcyanate), 4,4 '-ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanatophenylmethane), bis(4-cyanate-3,5-dimethyl Bifunctional cyanate resins such as phenyl)methane, 1,3-bis(4-cyanatophenyl-1-(methylethylidene))benzene, bis(4-cyanatophenyl)thioether, and bis(4-cyanatophenyl)ether; polyfunctional cyanate resins derived from phenol novolak, cresol novolak, etc.; prepolymers obtained by partially triazinizing these cyanate resins; and the like. Specific examples of cyanate ester curing agents include "PT30" and "PT60" (phenol novolac type polyfunctional cyanate ester resins), "ULL-950S" (polyfunctional cyanate ester resins) and "BADCy" manufactured by Lonza Japan. (bisphenol A dicyanate), "BA230", "BA230S75" (a prepolymer in which part or all of bisphenol A dicyanate is triazined to form a trimer).

Specific examples of carbodiimide curing agents include "V-03" and "V-07" manufactured by Nisshinbo Chemical Co., Ltd., and the like.

Amine-based curing agents include curing agents having one or more amino groups in one molecule, such as aliphatic amines, polyether amines, alicyclic amines, and aromatic amines. mentioned. Among them, aromatic amines are preferred. Amine-based curing agents are preferably primary amines or secondary amines, more preferably primary amines. Specific examples of amine-based curing agents include 4,4′-methylenebis(2,6-dimethylaniline), diphenyldiaminosulfone, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylsulfone, and 3,3′. -diaminodiphenyl sulfone, m-phenylenediamine, m-xylylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl- 4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, 2,2-bis(3-amino-4-hydroxyphenyl)propane, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethane Diamine, 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-based curing agents may be used. Kayahard AS", "Epicure W" manufactured by Mitsubishi Chemical Co., Ltd., and the like.

Acid anhydride curing agents include curing agents having one or more acid anhydride groups in one molecule. Specific examples of acid anhydride curing agents include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, and hydrogenated methylnadic acid. anhydride, trialkyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trianhydride mellitic acid, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'- Diphenylsulfonetetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan-1 , 3-dione, ethylene glycol bis(anhydrotrimellitate), polymer-type acid anhydrides such as styrene/maleic acid resin obtained by copolymerizing styrene and maleic acid. Commercially available acid anhydride curing agents include "HNA-100" and "MH-700" manufactured by Shin Nippon Rika.

The curing agent preferably contains an active ester curing agent. When an active ester-based curing agent is used, the content of the active ester-based curing agent with respect to 100% by mass of the curing agent is preferably 40% by mass or more, more preferably 50% by mass or more, and still more preferably 60% by mass or more, It is usually 100% by mass or less, preferably 98% by mass or less, more preferably 96% by mass or less, and even more preferably 94% by mass or less. It is preferable to use an active ester curing agent from the viewpoint that the surface roughness can be further reduced and the dielectric loss tangent can be reduced.

The amount of the curing agent in the resin composition is preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 5% by mass or more, relative to 100% by mass of non-volatile components in the resin composition. is 70% by mass or less, more preferably 60% by mass or less, and still more preferably 50% by mass or less.

When the number of epoxy groups of the epoxy resin is 1, the number of active groups of the curing agent is preferably 0.1 or more, more preferably 0.2 or more, still more preferably 0.3 or more, and preferably 3 or less, more preferably is 2.0 or less, more preferably 1.6 or less. The “epoxy group number of the epoxy resin” is the sum of all the values obtained by dividing the mass of the non-volatile component of the epoxy resin present in the resin composition by the epoxy equivalent. "The number of active groups of the curing agent" is the sum of all the values obtained by dividing the mass of the non-volatile component of the curing agent present in the resin composition by the active group equivalent. When the number of active groups of the curing agent is within the above range when the number of epoxy groups of the epoxy resin is 1, it is usually possible to improve the heat resistance of the cured product of the resin composition.

The resin composition contained in the resin composition layer may contain a thermoplastic resin, if necessary. Examples of thermoplastic resins include phenoxy resins, polyvinyl acetal resins, polyolefin resins, polybutadiene resins, polyimide resins, polyamideimide resins, polyetherimide resins, polysulfone resins, polyethersulfone resins, polyphenylene ether resins, polycarbonate resins, polyether resins. Ether ketone resins, polyester resins and the like can be mentioned. One type of thermoplastic resin may be used alone, or two or more types may be used in combination. Among them, a phenoxy resin is preferable from the viewpoint of obtaining an insulating layer having a small surface roughness and particularly excellent adhesion to the conductor layer.

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 skeletons selected from the group consisting of skeletons and trimethylcyclohexane skeletons. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. Specific examples of the phenoxy resin include Mitsubishi Chemical's "1256" and "4250" (both bisphenol A skeleton-containing phenoxy resins); Mitsubishi Chemical's "YX8100" (bisphenol S skeleton-containing phenoxy resin); Mitsubishi Chemical "YX6954" (bisphenolacetophenone skeleton-containing phenoxy resin) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.; "FX280" and "FX293" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.; "YL7769BH30", "YL6794", "YL7213", "YL7290" and "YL7482";

Examples of polyvinyl acetal resins include polyvinyl formal resins and polyvinyl butyral resins, and polyvinyl butyral resins are preferred. Specific examples of polyvinyl acetal resins include Denka Butyral 4000-2, Denka Butyral 5000-A, Denka Butyral 6000-C, and Denka Butyral 6000-EP manufactured by Sekisui Chemical Co., Ltd. S-LEC BH series, BX series (eg BX-5Z), KS series (eg KS-1), BL series, BM series;

Specific examples of the polyimide resin include "Ricacoat SN20" and "Ricacoat PN20" manufactured by Shin Nippon Rika. Specific examples of polyimide resins also include linear polyimides obtained by reacting bifunctional hydroxyl group-terminated polybutadiene, diisocyanate compounds and tetrabasic acid anhydrides (polyimides described in JP-A-2006-37083), and polysiloxane skeletons. Examples include modified polyimides such as polyimide containing (polyimides described in JP-A-2002-12667 and JP-A-2000-319386).

Specific examples of polyamide-imide resins include "VYLOMAX HR11NN" and "VYLOMAX HR16NN" manufactured by Toyobo Co., Ltd. Specific examples of polyamideimide resins include modified polyamideimides such as "KS9100" and "KS9300" (polysiloxane skeleton-containing polyamideimides) manufactured by Hitachi Chemical Co., Ltd.

Specific examples of the polyethersulfone resin include "PES5003P" manufactured by Sumitomo Chemical Co., Ltd., and the like.

Specific examples of the polyphenylene ether resin include oligophenylene ether/styrene resin "OPE-2St 1200" manufactured by Mitsubishi Gas Chemical Company, Inc., and the like.

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

The weight average molecular weight (Mw) of the thermoplastic resin is preferably 8,000 or more, more preferably 10,000 or more, particularly preferably 20,000 or more, preferably 70,000 or less, more preferably 60,000. 50,000 or less is particularly preferable. When the weight-average molecular weight (Mw) of the thermoplastic resin is within the above range, the dielectric constant and linear thermal expansion coefficient of the cured product of the resin composition can usually be reduced, and the mechanical strength of the cured product can be increased.

When a thermoplastic resin is used, the amount of the thermoplastic resin in the resin composition is preferably 0.1% by mass or more, more preferably 0.2% by mass, based on 100% by mass of non-volatile components in the resin composition. Above, more preferably 0.3% by mass or more, preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less. When the amount of the thermoplastic resin is within the above range, it is usually possible to reduce the dielectric constant and linear thermal expansion coefficient of the cured product of the resin composition and to increase the mechanical strength of the cured product.

The resin composition contained in the resin composition layer may contain a curing accelerator, if necessary. Examples of curing accelerators include phosphorus-based curing accelerators, amine-based curing accelerators, imidazole-based curing accelerators, guanidine-based curing accelerators, metal-based curing accelerators, and the like. The curing accelerator may be used alone or in combination of two or more. Among them, phosphorus-based curing accelerators and amine-based curing accelerators are preferred.

Phosphorus curing accelerators include, for example, triphenylphosphine, phosphonium borate compounds, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, (4-methylphenyl)triphenylphosphonium thiocyanate. , tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate, and triphenylphosphine and tetrabutylphosphonium decanoate are preferred.

Examples of amine curing accelerators include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine (DMAP), benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, 1, 8-diazabicyclo(5,4,0)-undecene, etc., and 4-dimethylaminopyridine and 1,8-diazabicyclo(5,4,0)-undecene are preferred.

Examples of imidazole curing accelerators include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl- 2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecyl imidazolyl-(1′)]-ethyl-s-triazine, 2,4-diamino-6-[2′-ethyl-4′-methylimidazolyl-(1′)]-ethyl-s-triazine, 2,4- Diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanurate, 2-phenylimidazole isocyanurate, 2-phenyl-4,5-dihydroxymethylimidazole, 2- Phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline , 2-phenylimidazoline and the like, and adducts of imidazole compounds and epoxy resins, with 2-ethyl-4-methylimidazole and 1-benzyl-2-phenylimidazole being preferred.

As the imidazole-based curing accelerator, a commercially available product may be used, such as "P200-H50" manufactured by Mitsubishi Chemical Corporation.

Guanidine curing accelerators include, for example, dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, Tetramethylguanidine, Pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0] Dec-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1 -allylbiguanide, 1-phenylbiguanide, 1-(o-tolyl)biguanide and the like, with dicyandiamide and 1,5,7-triazabicyclo[4.4.0]dec-5-ene being preferred.

Metal-based curing accelerators include, for example, organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include organocobalt complexes such as cobalt (II) acetylacetonate and cobalt (III) acetylacetonate, organocopper complexes such as copper (II) acetylacetonate, and zinc (II) acetylacetonate. and the like, organic iron complexes such as iron (III) acetylacetonate, organic nickel complexes such as nickel (II) acetylacetonate, and organic manganese complexes such as manganese (II) acetylacetonate. Examples of organic metal salts include zinc octoate, tin octoate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

When using a curing accelerator, the amount of the curing accelerator in the resin composition is preferably 0.01% by mass or more, more preferably 0.02% by mass, relative to 100% by mass of non-volatile components in the resin composition. Above, more preferably 0.03% by mass or more, preferably 3.0% by mass or less, more preferably 2.0% by mass or less, and even more preferably 1.0% by mass or less. When the amount of the curing accelerator is within the above range, the dielectric constant and linear thermal expansion coefficient of the cured product of the resin composition can generally be reduced, and the mechanical strength of the cured product can be increased.

The resin composition contained in the resin composition layer may contain an inorganic filler, if necessary. The inorganic filler can be usually contained in the resin composition in the form of particles.

As the material for the inorganic filler, an inorganic compound is usually used. Examples of inorganic filler materials include silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, Magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide , barium titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. The inorganic filler material may be used singly or in combination of two or more. Among these, silica is particularly suitable. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. As silica, spherical silica is preferable.

Examples of commercially available inorganic fillers include "SP60-05" and "SP507-05" manufactured by Nippon Steel & Sumikin Materials; "YC100C", "YA050C", "YA050C-MJE" and " YA010C"; "Silfil NSS-3N", "Silfil NSS-4N", "Silfil NSS-5N" manufactured by Tokuyama; "SC2500SQ", "SO-C4", "SO-C2", " SO-C1"; Denka's "UFP-30", "DAW-03", "FB-105FD" and the like.

The average particle size of the inorganic filler is not particularly limited, but is preferably 0.01 μm or more, more preferably 0.05 μm or more, particularly preferably 0.1 μm or more, and more preferably 10 μm or less, and more preferably. is 5 μm or less, particularly preferably 1 μm or less.
The average particle size of the inorganic filler can be measured by a laser diffraction/scattering method based on Mie scattering theory. Specifically, the particle size distribution of the inorganic filler is prepared on a volume basis using a laser diffraction/scattering type particle size distribution measuring device, and the median diameter can be used as the average particle size for measurement. A measurement sample can be obtained by weighing 100 mg of an inorganic filler and 10 g of methyl ethyl ketone in a vial and dispersing them with ultrasonic waves for 10 minutes. A measurement sample is measured using a laser diffraction particle size distribution measuring device, the wavelengths of the light source used are blue and red, the volume-based particle size distribution of the inorganic filler is measured by the flow cell method, and from the obtained particle size distribution The average particle size can be calculated as the median size. Examples of the laser diffraction particle size distribution analyzer include "LA-960" manufactured by Horiba, Ltd., and the like.

The specific surface area of the inorganic filler is not particularly limited, but is preferably 0.1 m ² /g or more, more preferably 0.5 m ² /g or more, and particularly preferably 1.0 m ² /g or more. , preferably 50 m ² /g or less, more preferably 30 m ² /g or less, and particularly preferably 15 m ² /g or less.
The specific surface area of the inorganic filler is determined by using a BET fully automatic specific surface area measuring device (Macsorb HM-1210 manufactured by Mountech) to adsorb nitrogen gas on the sample surface and calculating the specific surface area using the BET multipoint method. obtained by

The inorganic filler is preferably surface-treated with a suitable surface-treating agent. The surface treatment can enhance the moisture resistance and dispersibility of the inorganic filler. 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 compounds. A coupling agent etc. are mentioned. One type of surface treatment agent may be used alone, or two or more types may be used in combination.

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

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

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 more preferably 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 suppressing an increase in the melt viscosity of the resin composition and the melt viscosity in the sheet form, the amount of carbon per unit surface area of the inorganic filler is preferably 1.0 mg / m ² or less, and 0.8 mg / m ² or less is more preferable, and 0.5 mg/m ² or less is even more preferable.

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

When using an inorganic filler, the content of the inorganic filler in the resin composition is preferably 10% by mass or more, more preferably 20% by mass or more, relative to 100% by mass of the non-volatile components in the resin composition. More preferably 30% by mass or more, more preferably 50% by mass or more, particularly preferably 60% by mass or more, preferably 90% by mass or less, more preferably 80% by mass or less.

The resin composition contained in the resin composition layer may contain optional components other than those described above, if necessary. Examples of such optional components include organometallic compounds such as organocopper compounds, organozinc compounds and organocobalt compounds; resin additives such as surfactants; and the like. These components may be used singly or in combination of two or more.

There are no particular restrictions on the thickness of the resin composition layer. From the viewpoint of obtaining an insulating layer having high insulating ability, the thickness of the resin composition layer is preferably 5 μm or more, more preferably 10 μm or more. From the viewpoint of thinning the printed wiring board, the thickness of the resin composition layer is preferably 100 μm or less, more preferably 70 μm or less, and particularly preferably 50 μm or less.

[2.4. Method for manufacturing resin sheet]
There are no restrictions on the method of manufacturing the resin sheet. The resin sheet can be produced, for example, by a production method including a step of forming a release layer on a support and a step of forming a resin composition layer on the release layer.

There are no restrictions on the method of forming the release layer on the support. For example, the release layer is formed by a method comprising applying a release layer-forming liquid composition containing a release agent and a solvent onto a support, and drying the applied liquid composition. can.

As the solvent contained in the liquid composition, water may be used, an organic solvent may be used, or both may be used in combination. As the organic solvent, an amphiphilic organic solvent is preferred. An amphiphilic organic solvent is an organic solvent having a water solubility of 5% by mass or more in the organic solvent at 20°C. Specific examples of amphiphilic organic solvents include alcohol solvents, ether solvents, ketone solvents, ester solvents, ethylene glycol derivative solvents, amine solvents, lactam solvents and the like. The non-volatile component concentration of the liquid composition is not particularly limited, but is preferably 2% by mass to 30% by mass, more preferably 3% by mass to 20% by mass. In addition, the liquid composition may further contain optional components such as an antioxidant, an ultraviolet absorber, a lubricant, and a colorant in combination with the release agent and solvent.

Examples of methods for applying a liquid composition onto a support include gravure roll coating, reverse roll coating, wire bar coating, lip coating, air knife coating, curtain flow coating, spray coating, and dip coating. methods and brush coating methods. Among them, the gravure roll coating method is preferable.

A release layer is obtained on the support by applying the liquid composition on the support and then drying the applied liquid composition. The drying method is not particularly limited, and for example, drying by heating, drying under reduced pressure, and the like can be used.

After drying, the film comprising the support and release layer may be stretched, if desired. By stretching, the degree of oriented crystallization on the surface of the support can be reduced, so that the adhesion between the support and the release layer can be improved. Furthermore, after drying, the film comprising the support and release layer may be subjected to heat treatment. The heat treatment can enhance the releasability of the release layer. In particular, when drying, stretching, and heat treatment are performed by an in-line method, the release layer can be subjected to high-temperature heat treatment while the support is in tension, thereby improving release properties while suppressing deterioration in the quality of the release layer. be able to. For example, by adopting a sequential biaxial stretching method, a liquid composition is coated on a uniaxially stretched support, the coated liquid composition is dried, further stretched in a direction perpendicular to the above direction, and heat-treated. You may

There is no limitation on the method for forming the resin composition layer on the release layer. For example, the resin composition layer can be produced by a method including applying a resin varnish containing the resin composition and a solvent onto the release layer, and drying the applied resin varnish.

As the solvent, an organic solvent is usually used. Specific examples of solvents include ketone solvents such as acetone, methyl ethyl ketone (MEK) and cyclohexanone; acetic acid ester solvents such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate and carbitol acetate; carbitol solvents such as toll; aromatic hydrocarbon solvents such as toluene and xylene; amide solvents such as dimethylformamide, dimethylacetamide (DMAc) and N-methylpyrrolidone; A solvent may be used individually by 1 type, and may be used in combination of 2 or more types.

Examples of methods for applying a resin varnish on the release layer include gravure coating, micro gravure coating, reverse coating, kiss reverse coating, die coating, slot die, lip coating, comma coating, and blade coating. A coating method, a roll coating method, a knife coating method, a curtain coating method, a chamber gravure coating method, a slot orifice method, a spray coating method, a dip coating method and the like can be mentioned.

After applying the resin varnish on the release layer, the resin composition layer is obtained on the release layer by drying the applied resin varnish. The drying method is not particularly limited, and drying methods such as heat drying and hot air blow drying can be used. Although the drying conditions are not particularly limited, drying is performed so that the content of the organic solvent in the resin composition layer is usually 10% by mass or less, preferably 5% by mass or less. Although it varies depending on the boiling point of the organic solvent in the resin varnish, for example, when using a resin varnish containing 30% by mass to 60% by mass of the organic solvent, drying at 50 ° C. to 150 ° C. for 3 minutes to 10 minutes The resin composition layer can be formed.

The above method for producing a resin sheet may further include an optional step in combination with the step of forming a release layer on a support and the step of forming a resin composition layer on the release layer. . For example, the manufacturing method may include a step of winding the obtained resin sheet into a roll. Moreover, the manufacturing method may include a step of providing a protective film on the resin composition layer. The protective film can suppress dust adhesion and scratches on the resin composition layer. A resin sheet provided with a protective film can usually be used by peeling off the protective film.

[3. Second step: lamination of resin composition layer and substrate]
FIG. 2 is a cross-sectional view schematically showing the resin sheet 100 and the substrate 200 in the second step of the printed wiring board manufacturing method according to one embodiment of the present invention. As shown in FIG. 2, the printed wiring board manufacturing method according to one embodiment of the present invention includes a second step of laminating the resin composition layer 130 of the resin sheet 100 and the substrate 200 after the first step. conduct.

Examples of the substrate 200 include glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, thermosetting polyphenylene ether substrates, and the like. Also, the substrate 200 may have a conductor layer (not shown) on one side or both sides thereof as part of the substrate 200 . This conductor layer may be patterned, for example, to function as a circuit. As the substrate 200, an inner layer substrate for a printed wiring board may be used. Further, as the substrate 200, an inner layer circuit board may be used as an inner layer board having a conductor layer as a circuit on one side or both sides. Furthermore, an intermediate product on which an insulating layer and/or a conductor layer should be further formed when manufacturing a printed wiring board may be used as the substrate 200 . Further, the substrate 200 may contain components.

Lamination of the resin composition layer 130 and the substrate 200 is usually performed by thermocompression bonding the resin composition layer 130 and the substrate 200 together. As a specific example of the lamination method, there is a method in which the resin composition layer 130 and the substrate 200 are bonded together by thermocompression bonding the resin sheet 100 to the substrate 200 from the support 110 side. As a member for thermocompression bonding the resin sheet 100 to the substrate 200 (hereinafter sometimes referred to as a “thermocompression member”; not shown), for example, a heated metal plate (SUS mirror plate, etc.) or a metal roll (SUS roll ) and the like. Instead of directly pressing the thermocompression member onto the resin sheet 100 , it is preferable to press through an elastic material such as heat-resistant rubber so that the resin composition layer 130 can sufficiently follow the uneven surface of the substrate 200 .

Lamination of the resin composition layer 130 and the substrate 200 may be performed by, for example, a vacuum lamination method. In the vacuum lamination method, the thermocompression temperature is preferably in the range of 60° C. to 160° C., more preferably 80° C. to 140° C., and the thermocompression pressure is preferably 0.098 MPa to 1.77 MPa, more preferably 0. .29 MPa to 1.47 MPa, and the heat pressing time is preferably 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.

After lamination, the laminated resin sheets 100 may be smoothed by, for example, pressing a thermocompression member from the support 110 side under normal pressure (atmospheric pressure). The pressing conditions for the smoothing treatment may be the same as the thermocompression bonding conditions for the laminate. Lamination and smoothing may be performed sequentially using a vacuum laminator.

[4. Third step: Curing of resin composition layer]
FIG. 3 is a cross-sectional view schematically showing the resin sheet 100 and the substrate 200 in the third step of the printed wiring board manufacturing method according to one embodiment of the present invention. In FIG. 3, among the resin composition layers 130, the insulating layer as a cured resin composition layer is indicated by reference numeral "230". As shown in FIG. 3, in the method for manufacturing a printed wiring board according to one embodiment of the present invention, after the second step, resin composition layer 130 (see FIGS. 1 and 2) is cured to form insulating layer 230. Perform the third step to obtain

Curing of the resin composition layer 130 can be performed by a method according to the curability of the resin composition contained in the resin composition layer 130 . For example, when a thermosetting resin composition is used, the resin composition layer 130 can be cured by applying appropriate heat to the resin composition layer 130 .

The thermosetting conditions for the resin composition layer 130 may vary depending on the type of resin composition. The curing temperature is preferably 120°C to 240°C, more preferably 150°C to 220°C, still more preferably 170°C to 200°C. The curing time is preferably 5 minutes to 120 minutes, more preferably 10 minutes to 100 minutes, even more preferably 15 minutes to 90 minutes.

Before thermally curing the resin composition layer 130 as described above, the resin composition layer 130 may be preheated at a temperature lower than the curing temperature. For example, prior to thermosetting the resin composition layer 130, the resin composition layer is heated at a temperature of 50° C. or more and less than 120° C. (preferably 60° C. or more and 115° C. or less, more preferably 70° C. or more and 110° C. or less). 130 may be preheated for 5 minutes or more (preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes, still more preferably 15 minutes to 100 minutes).

[5. Sixth step: hole formation]
FIG. 4 is a cross-sectional view schematically showing the resin sheet 100 and the substrate 200 in which the holes 140 are formed in the sixth step of the printed wiring board manufacturing method according to one embodiment of the present invention. As shown in FIG. 4, in the method for manufacturing a printed wiring board according to one embodiment of the present invention, after the third step and before the fifth step, an insulating layer 230 as a cured resin composition layer is coated with A sixth step of forming holes 140 may be performed.

Hole 140 is generally formed to penetrate insulating layer 230 in the thickness direction. In addition, since the release layer 120 is usually removed at the portion where the hole 140 is formed, the hole 140 is formed not only in the insulating layer 230 but also in the release layer 120 . Since FIG. 4 shows an example in which the holes 140 are formed before the fourth step, the holes 140 are also formed in the support 110 . When the hole 140 is formed before the fourth step, it is easy to form the well-shaped hole 140 by suppressing the occurrence of hollowed portions (not shown). However, the hole 140 may be formed after the fourth step. When the hole 140 is formed after the fourth step, the hole 140 is normally formed in the insulating layer 230 and the release layer 120 (residual release layer 121 to be described later) on the insulating layer 230 .

A suitable method for forming the hole 140 can be adopted according to the composition of the resin composition used to form the insulating layer 230 . Examples of the method for forming the hole 140 include laser irradiation, etching, mechanical drilling, and the like. The hole 140 thus formed can be used as a via hole or through hole of a printed wiring board. The size and shape of hole 140 can be appropriately determined according to the design of the printed wiring board.

When the hole 140 is formed by drilling the insulating layer 230 as described above, a smear 240 may be formed as shown in FIG. Normally, smear 240 is formed to protrude from the inner wall of hole 140 opened in insulating layer 230 . This smear 240 is removed in the fifth step, which will be described later.

[6. Fourth step: peeling of support]
FIG. 5 is a cross-sectional view schematically showing intermediate multilayer body 300 and peeling body 400 obtained in the fourth step of the printed wiring board manufacturing method according to one embodiment of the present invention. As shown in FIG. 5, in the printed wiring board manufacturing method according to the embodiment of the present invention, the fourth step of peeling off the support 110 is performed after the third step.

The support 110 is peeled off so that at least a portion 121 of the release layer 120 remains on the insulating layer (resin composition layer after curing) 230 . Therefore, by peeling the support 110, the intermediate multilayer body 300 having the substrate 200, the insulating layer 230, and at least a portion 121 of the release layer 120 in this order in the thickness direction is obtained. In the following description, at least a portion 121 of the release layer 120 included in the intermediate multilayer body 300 may be referred to as a "residual release layer" 121 as appropriate. The residual release layer 121 is a layer containing a release agent attached to the insulating layer 230, and may be the entire release layer 120 included in the resin sheet 100, or a part of the release layer 120. Preferably. Unless otherwise specified, "at least part", "part" and "whole" of the release layer 120 represent "at least part", "part" and "whole" in the thickness direction, respectively. FIG. 5 shows an example in which part of the release layer 120 included in the resin sheet 100 remains on the insulating layer 230 to form a residual release layer 121 .

In the fourth step, since the support 110 is peeled off, the peeled body 400 including the peeled support 110 is obtained. When the support 110 is peeled so that part of the release layer 120 remains on the insulating layer 230 as the residual release layer 121, part of the release layer 120 is attached to the peeled support 110. A portion 122 may be attached. In the following description, the portion 122 of the release layer 120 adhered to the support 110 may be referred to as a "peeling release layer" 122 as appropriate. Therefore, in this case, the release body 400 including the support 110 and the release layer 122 can be obtained. Further, when the support 110 is peeled off so that the entire release layer 120 remains on the insulating layer 230 as the residual release layer 121, the peeled body 400 adheres to the support 110. It does not include the mold layer 122 . FIG. 5 shows an example in which the release body 400 includes the support 110 and the release layer 122 .

There is no limitation on the method of peeling off the support 110 . For example, support 110 may be pulled, substrate 200 may be pulled, or both support 110 and substrate 200 may be pulled.

There are various methods for obtaining the intermediate multilayer body 300 by peeling the support 110 . For example, there is a method of using a release agent that can cause cohesive failure when the support 110 is peeled off as the material of the release layer 120 . The cohesive failure of the release agent means destruction inside the release agent. When a release agent capable of causing cohesive failure is used, due to the action of the stress applied when the support 110 is peeled off, the release layer 120 is separated from the inside of the release layer 120 at the same time as the support 110 is peeled off. can be destroyed by Therefore, the release layer 120 can be divided into a residual release layer 121 that remains on the insulating layer 230 and a peeled release layer 122 that is peeled off together with the support 110 . Therefore, intermediate multilayer body 300 including residual release layer 121 can be obtained. A release agent capable of causing cohesive failure when the support 110 is peeled off in this manner can be obtained by appropriately adjusting the composition of the release agent.

Another method of obtaining the intermediate multilayer body 300 by peeling off the support 110 is, for example, to combine the material of the support 110 and the material of the release layer 120 (i.e., release agent) with an affinity for each other. is adjusted to a low combination. When the support 110 and the release layer 120 are formed of a material with low affinity, the support 110 and the release layer 120 are separated from each other by the action of stress applied when the support 110 is peeled off. Separation is possible at the interface with the release layer 120 . Therefore, the entire release layer 120 may remain on the insulating layer 230 to form a residual release layer 121 . Therefore, intermediate multilayer body 300 including residual release layer 121 can be obtained. A combination of the material of the support 110 and the release agent having such low affinity can be obtained by adjusting the composition of one or both of the material of the support 110 and the release agent.
However, the method of obtaining the intermediate multilayer body 300 by peeling the support 110 is not limited to the above example.

Before undergoing the oxidation treatment in the fifth step, the intermediate multilayer body 300 includes, in the thickness direction, the substrate 200, the insulating layer 230 as the cured resin composition layer, the residual release layer 121, and the release layer 121. The surfaces 300U are provided in this order. The release surface (that is, the surface on the side of the residual release layer 121) 300U of the intermediate multilayer body 300 preferably has a specific water contact angle _θA . Specifically, the water contact angle θ _A of the release surface 300U before the fifth step is preferably 75° or more, more preferably 80° or more, particularly preferably 85° or more, and preferably 110°. 100° or less, particularly preferably 95° or less. Such a large water contact angle θ _A can be obtained, for example, when a release agent with low polarity is used. When the release surface 300U of the intermediate multilayer body 300 has the water contact angle θ _A within the above range, the residual release layer 121 can have high resistance to oxidants. Therefore, since the residual release layer 121 can effectively protect the insulating layer 230 from the oxidizing agent, the surface roughness of the insulating layer 230 after the fifth step can be effectively reduced.

The water contact angle of the surface can be measured at 25° C. by a perfect circle method using a water contact angle measuring device (Drop Master “DMs-401” manufactured by Kyowa Interface Science Co., Ltd.).

The difference between the water contact angle θ _A of the release surface 300U before the fifth step and the water contact angle θ _B of the release layer 120 side surface 130U (see FIG. 2) of the resin composition layer 130 before curing. The absolute value of |θ _A −θ _B | is preferably within a specific range. Specifically, the absolute value |θ _A −θ _B | is preferably 8° or more, more preferably 10° or more, and particularly preferably 13° or more. There is no upper limit, but it can be, for example, 35° or less.

In many cases, the resin composition before curing and the release agent have different affinities for water. Such a difference in affinity for water is the water contact angle θ _A of the release surface 300U as the surface of the residual release layer and the water contact angle θ _B of the surface 130U of the resin composition layer 130 before curing. difference can be reflected. In addition, the affinity for water of the resin composition layer 130 before curing can be correlated with the affinity for water of the insulating layer after curing. Therefore, the difference between the water contact angle θ _A and the water contact angle θ _B may indicate that there is a property difference between the residual release layer 121 and the insulating layer 230 .

The water contact angle of surface 130U of resin composition layer 130 before curing can be measured, for example, by the following method. That is, after the second step, the support 110 and the release layer 120 are peeled off before the resin composition layer 130 is cured. Since surface 130U of resin composition layer 130 can be exposed by peeling, the water contact angle of surface 130U can be measured.

According to the water contact angle θ _A of the release surface 300U, it can be confirmed that the release layer 121 remains on the insulating layer 230 . In general, a difference in water contact angle can occur between the surface to which the release agent is adhered and the surface to which it is not adhered. Therefore, when the release surface 300U has a water contact angle θ _A that differs from the water contact angle θ _B of the surface 130U of the resin composition layer 130 to which the release agent is not attached, Since it can be seen that the release agent adheres to the mold surface 300U, it can be seen that the release layer 121 remains on the insulating layer 230 . Specifically, if the absolute value |θ _A −θ _B | 121 can be determined.

Also, by using the water contact angle, it can be confirmed that the release body 400 includes the release layer 122 . The water contact angle θ _C of the release layer side surface 400D of the release body 400 obtained in the fourth step may vary depending on the presence or absence of the release layer 122 . Here, the release layer side surface 400D of the release body 400 represents the surface exposed by the release of the support 110, and thus the surface that was in contact with the remaining release layer 121 before the release of the support 110. show. The surface 400D of the peeling body 400 may be referred to as the “peeling surface” 400D of the peeling body 400 as appropriate.

When the release body 400 includes the release layer 122, the release body 400 includes the support 110, the release layer 122, and the release surface 400D in this order in the thickness direction. Therefore, in this case, the release surface 400D can correspond to the surface of the release layer 122 . Then, the release surface 400D can have a water contact angle θ _C that is approximately the same as the water contact angle θ _A of the release surface 300U of the intermediate multilayer body 300, which also corresponds to the surface of the layer containing the release agent. Therefore, when the _absolute value of the difference |θ _A −θ _{C |} It can be seen that body 400 includes a release release layer 122 . Specifically, the absolute value |θ _A −θ _C | It can be determined that the release layer 122 is included.

On the other hand, when the release body 400 does not include the release layer 122, the release body 400 includes the support 110 and the release surface 400D in this order in the thickness direction. Therefore, in this case, the release surface 400</b>D does not correspond to the surface of the release layer 122 . Therefore, the release surface 400D can have a water contact angle θ _C that is significantly different from the water contact angle θ _A of the release surface 300U of the intermediate multilayer body 300 . Therefore, if the absolute value |θ _A −θ _{C |} of the difference between the water contact angle θ _A of the release surface 300U of the intermediate multilayer body 300 and the water contact angle It can be seen that body 400 does not include release layer 122 . Specifically, when the absolute value |θ _A −θ _C | is outside the range, it can be determined that the release body 400 does not include the release layer 122 .

After the second step and before curing the resin composition layer 130, the support 110 and the release layer 120 are peeled off to form a release film (not shown) comprising the support 110 and the release layer 120. get Using the water contact angle θ _D of the surface of the release film on the release layer 120 side, it can be confirmed that the release body 400 includes the release layer 122 .

As described above, when the release body 400 includes the release layer 122, the release surface 400D corresponding to the surface of the release layer 122 corresponds to the surface of the release layer 120 that also contains a release agent. The film may have a water contact angle θ _C that is approximately the same as the water contact angle θ _D of the release layer 120 side of the film. Therefore, when the absolute value of _the difference |θ _C −θ _{D |} It can be seen that the release body 400 includes a release release layer 122 . Specifically, when the absolute value |θ _C −θ _D | is usually 13° or less, preferably 10° or less, and particularly preferably 8° or less, the release body 400 includes the release layer 122. can be determined.

On the other hand, when the release body 400 does not include the release layer 122, as described above, the release surface 400D, which does not correspond to the surface of the release layer 122, does not contact the release layer 120 side of the release film. It can have a water contact angle θ _C that is significantly different from the angle θ _D . _Therefore , when the absolute value of the difference |θ _C −θ _{D |} It can be seen that the release body 400 does not include the release release layer 122 . Specifically, when the absolute value |θ _C −θ _D | is outside the range, it can be determined that the release body 400 does not include the release layer 122 .

The presence of a release layer, a residual release layer, and a peeled release layer on a certain surface can also be confirmed by observation with a scanning electron microscope (SEM). The surface shape is different between the surface with the release layer, the residual release layer, or the peeled release layer and the surface without the release layer. Therefore, it can be confirmed that there is a release layer, a residual release layer, and a peeled release layer by observing the surface shape by SEM.

[7. Fifth step: oxidation treatment]
FIG. 6 is a cross-sectional view schematically showing printed wiring board 500 obtained by subjecting intermediate multilayer body 300 to oxidation treatment in the fifth step of the method for manufacturing printed wiring board 500 according to one embodiment of the present invention. be. In the method for manufacturing a printed wiring board according to one embodiment of the present invention, after the fourth step, an oxidizing treatment is performed to bring an oxidizing agent into contact with the release surface 300U of the intermediate multilayer body 300, and the printed wiring board shown in FIG. A fifth step of obtaining wiring board 500 is performed. In this oxidation treatment, if holes 140 are formed in insulating layer 230, an oxidizing agent is usually brought into contact with the entire release surface 300U including the portions where holes 140 are formed.

In the fifth step of the manufacturing method according to the present embodiment, it is possible to achieve both improvement in smear removability and reduction in surface roughness of the insulating layer. The present inventor presumes that the mechanism by which such effects are obtained is as follows. However, the technical scope of the present invention is not limited by the mechanism described below.

In the fifth step, when the oxidizing agent contacts the release surface 300U of the intermediate multilayer body 300, the oxidizing agent enters the holes 140 at the positions where the holes 140 are formed. The oxidant entering the hole 140 oxidizes and removes the smear 240 . On the release surface 300U of the intermediate multilayer body 300, the residual release layer 121 is not provided at the positions where the holes 140 are formed. Therefore, the oxidant can smoothly enter the hole 140 and effectively remove the smear 240 .

On the other hand, on the release surface 300U of the intermediate multilayer body 300, a residual release layer 121 is provided on the insulating layer 230 at positions where the holes 140 are not formed. Therefore, since the insulating layer 230 is protected by the residual release layer 121 , the oxidizing agent cannot smoothly enter the insulating layer 230 . Specifically, the oxidizing agent typically penetrates into insulating layer 230 after removing residual release layer 121 by oxidation. When the oxidizing agent enters the insulating layer 230, the surface 230U of the insulating layer 230 is roughened. progress of roughening is suppressed. Therefore, it is possible to achieve low roughness of the surface 230U of the insulating layer 230 obtained after the oxidation treatment. The surface 230U of the insulating layer 230 after the oxidation treatment is sometimes referred to as a "roughened surface" 230U. In addition, since residual release layer 121 is usually removed by oxidation with an oxidizing agent, printed wiring board 500 obtained does not contain residual release layer 121 .

Examples of the oxidizing agent include, but are not limited to, an alkaline permanganate solution in which potassium permanganate or sodium permanganate is dissolved in an aqueous solution of sodium hydroxide. The permanganate concentration 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 P", "Concentrate Compact CP", and "Dosing Solution Security P" manufactured by Atotech Japan. . One type of oxidizing agent may be used alone, or two or more types may be used in combination.

The method of bringing the oxidizing agent into contact with the release surface 300U is not particularly limited. For example, the intermediate multilayer body 300 may be immersed in an oxidant to bring the release surface 300U into contact with the oxidant. Moreover, it is preferable to appropriately set the processing conditions when the oxidizing agent is brought into contact with the release surface 300U so that the smear 240 can be removed. For example, the oxidation treatment with an oxidizing agent such as an alkaline permanganate solution is preferably carried out by bringing the oxidizing agent heated to 60° C. to 80° C. into contact with the release surface 300U for 10 minutes to 30 minutes.

The fifth step preferably includes a swelling treatment of bringing a swelling liquid into contact with the release surface 300U of the intermediate multilayer body 300 before the oxidation treatment. Examples of the swelling liquid include, but are not limited to, alkaline solutions, surfactant solutions, and the like. Among the swelling liquids, an alkaline solution is preferable, and a sodium hydroxide solution and a potassium hydroxide solution are more preferable. Examples of commercially available swelling liquids include "Swelling Dip Securigant P" and "Swelling Dip Securigant SBU" manufactured by Atotech Japan. One swelling liquid may be used alone, or two or more swelling liquids may be used in combination.

The swelling treatment with the swelling liquid is not particularly limited, but for example, the intermediate multilayer body 300 may be immersed in the swelling liquid to bring the release surface 300U into contact with the swelling liquid. The temperature of the swelling liquid is preferably 30.degree. C. to 90.degree. C., more preferably 40.degree. C. to 80.degree. The time for which the swelling liquid is brought into contact with the release surface 300U is preferably 1 to 20 minutes, more preferably 5 to 15 minutes, from the viewpoint of suppressing the swelling of the insulating layer 230 to an appropriate level.

The fifth step preferably includes a neutralization treatment of bringing a neutralizing liquid into contact with roughened surface (230U) of insulating layer 230 of printed wiring board 500 obtained after the oxidation treatment. As the neutralizing liquid, an acidic aqueous solution is preferable. Commercially available neutralizing solutions include, for example, "Reduction Solution Securigant P" manufactured by Atotech Japan. One type of neutralizing liquid may be used alone, or two or more types may be used in combination.

The neutralization treatment using the neutralizing liquid is not particularly limited, but for example, printed wiring board 500 may be immersed in the neutralizing liquid so that roughened surface 230U is brought into contact with the neutralizing liquid. The temperature of the neutralization solution is preferably 30°C to 80°C, more preferably 40°C to 70°C, from the viewpoint of workability. In addition, the time for contacting the roughened surface 230U with the neutralizing liquid is preferably 5 minutes to 30 minutes, more preferably 5 minutes to 20 minutes, from the viewpoint of workability.

According to the fifth step, printed wiring board 500 having substrate 200, insulating layer 230, and roughened surface 230U in this order in the thickness direction is obtained. Further, in the present embodiment, the roughness of the roughened surface 230U can be reduced. The arithmetic mean roughness Ra of the roughened surface 230U is preferably 400 nm or less, more preferably 300 nm or less, still more preferably 200 nm or less, and particularly preferably 150 nm or less. Although the lower limit is not particularly limited, it is preferably 20 nm or more, more preferably 30 nm or more.

Arithmetic mean roughness Ra of roughened surface 230U of printed wiring board 500 is measured in VSI mode using a non-contact surface roughness meter ("WYKO NT3300" manufactured by BCo Instruments) at a position where hole 140 is not formed. , with a 50× lens, the measurement range is 121 μm×92 μm.

If the hole 140 is formed in the insulating layer 230, the smear 240 in the hole 140 can be removed according to the fifth step. Therefore, for example, the maximum smear length from the bottom wall of the hole 140 can be reduced to less than 5 μm. The maximum smear length can be measured by observing the periphery of the bottom of hole 140 with a scanning electron microscope (SEM). Further, the wall surface at the bottom of the hole 140 represents the wall surface of the hole 140 near the substrate 200 .

[8. Seventh step: formation of conductor layer]
FIG. 7 is a cross-sectional view schematically showing printed wiring board 500 on which conductor layer 250 is formed in the seventh step of the method for manufacturing printed wiring board 500 according to the first embodiment of the present invention. As shown in FIG. 7, in the method for manufacturing printed wiring board 500 according to one embodiment of the present invention, the seventh step of forming conductor layer 250 may be performed after the fifth step. In the seventh step, usually, conductor layer 250 is formed on roughened surface (230U) of insulating layer 230 to obtain printed wiring board 500 having substrate 200, insulating layer 230, and conductor layer 250 in this order in the thickness direction.

A conductor material used for the conductor layer 250 is not particularly limited. In a preferred embodiment, the conductor layer 250 is 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. metals. The conductor layer 250 may be a single metal layer or an alloy layer. The alloy layer includes, for example, 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 them, from the viewpoint of versatility, cost, and ease of patterning of the conductor layer 250, a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper; or a nickel-chromium alloy; An alloy layer of a copper-nickel alloy or a copper-titanium alloy; is preferred. Furthermore, a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper; or an alloy layer of a nickel-chromium alloy; is more preferred, and a single metal layer of copper is even more preferred.

The conductor layer 250 may have a single layer structure, or may have a multi-layer structure including two or more single metal layers or alloy layers made of different kinds of metals or alloys. When the conductor layer 250 has a multi-layer structure, the layer in contact with the insulating layer 230 is preferably a single metal layer of chromium, zinc or titanium, or an alloy layer of a nickel-chromium alloy.

The thickness of conductor layer 250 is generally between 3 μm and 35 μm, preferably between 5 μm and 30 μm, depending on the desired printed wiring board 500 design.

The conductor layer 250 may be formed by plating. For example, the roughened surface 230U of the insulating layer 230 can be plated by techniques such as a semi-additive method and a full-additive method to form the conductor layer 250 having a desired wiring pattern. Among them, the semi-additive method is preferable from the viewpoint of manufacturing simplicity.

An example of forming the conductor layer 250 by a semi-additive method is shown below. First, a plating seed layer is formed on the surface 230U of the insulating layer 230 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 electroplating, the mask pattern is removed. After that, the unnecessary plating seed layer is removed by etching or the like, and the conductor layer 250 having the desired wiring pattern can be formed.

In the manufacturing method according to this embodiment, the roughness of the roughened surface 230U of the insulating layer 230 is reduced. Therefore, when the conductor layer 230 has a wiring pattern, the wiring pattern can be miniaturized.

Moreover, when the hole 140 is formed in the insulating layer 230 , the conductor layer 250 is normally also formed in the hole 140 . Since the smear 240 is effectively removed, the formation of defects in the conductor layer 250 formed in the hole 250 is suppressed.

[9. Modification]
The printed wiring board manufacturing method according to the embodiment described above may be further modified and implemented. For example, a multilayer printed wiring board may be manufactured by repeating the formation of an insulating layer and a conductor layer according to the steps described above, if necessary. Further, for example, steps other than the first to seventh steps described above may be performed.

[10. Uses of manufactured printed wiring boards]
A printed wiring board manufactured by the manufacturing method described above can be applied to a wide range of semiconductor devices. Semiconductor devices with printed wiring boards are used, for example, in electrical appliances (e.g., computers, mobile phones, digital cameras, televisions, etc.) and vehicles (e.g., motorcycles, automobiles, trains, ships, aircraft, etc.). Various semiconductor devices are mentioned.

A semiconductor device can be manufactured, for example, by mounting a component (semiconductor chip) on a conductive portion of a printed wiring board. A "conducting part" is a "part where an electric signal is transmitted on a printed wiring board", and the place may be a surface or an embedded part. Moreover, the semiconductor chip can arbitrarily use an electric circuit element made of a semiconductor.

A method of mounting a semiconductor chip when manufacturing a semiconductor device is not particularly limited as long as the semiconductor chip functions effectively. Examples of mounting methods include wire bonding mounting method, flip chip mounting method, mounting method by bumpless build-up layer (BBUL), mounting method by anisotropic conductive film (ACF), and mounting by non-conductive film (NCF). methods, and the like. Here, "a mounting method using a build-up layer without bumps (BBUL)" refers to a "mounting method in which a semiconductor chip is directly embedded in a concave portion of a printed wiring board and the semiconductor chip and wiring on the printed wiring board are connected." is.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to Examples. However, the present invention is not limited to the following examples. In the following description, "parts" and "%" representing amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified. In addition, unless otherwise specified, the operations described below were performed in an environment of normal temperature and normal pressure.

[Evaluation method]
The thickness of the layer was measured at 25° C. by a curve fitting method using “Optical Nano Gauge C12562” manufactured by Hamamatsu Photonics. The measurement was performed at 10 measurement points, and the average value of the 10 points was obtained to obtain the measured value.

(Method for measuring water contact angle)
The water contact angle of the surface was measured at 25° C. by the perfect circle method using a water contact angle measuring device (Drop Master “DMs-401” manufactured by Kyowa Interface Science Co., Ltd.). The measurement was performed at 5 measurement points, and the average value of the 5 points was obtained to obtain the measured value.

(Measurement of arithmetic mean roughness (Ra value) of surface of insulating layer)
The arithmetic mean roughness (Ra value) of the surface of the insulating layer is measured using a non-contact surface roughness meter (“WYKO NT3300” manufactured by Bcoinstruments) in VSI mode with a 50x lens, measuring range 121 μm × 92 μm. It was obtained from the numerical value obtained as The measurement was performed at 10 measurement points, and the average value of the 10 points was obtained to obtain the measured value.

[Production Example 1. Production of release film 1]
<Production of acid-modified polypropylene resin (A-1)>
280 g of a propylene-ethylene copolymer (propylene/ethylene=99/1 (mass ratio)) was heated and melted in a four-necked flask under a nitrogen atmosphere. After that, 32.0 g of maleic anhydride as an unsaturated carboxylic acid and 6.0 g of dicumyl peroxide as a radical generator were added over 1 hour with stirring while maintaining the system temperature at 170°C. Then, it was made to react for 1 hour. After completion of the reaction, the obtained reaction product was poured into a large amount of acetone to precipitate a resin. The resin was further washed several times with acetone to remove unreacted maleic anhydride. Thereafter, the resin was dried under reduced pressure in a vacuum dryer to obtain an acid-modified polyolefin resin (A-1).

<Production of aqueous dispersion of acid-modified polypropylene resin (A-1)>
A stirrer equipped with a heater and a sealable pressure-resistant 1 liter glass vessel was provided. 60.0 g of acid-modified polyolefin resin (A-1), 45.0 g of ethylene glycol-n-butyl ether (boiling point 171° C.), and 6.9 g of N,N-dimethylethanolamine were placed in a glass container of this stirrer. (boiling point 134° C., 1.0-fold equivalent with respect to the carboxyl group of the maleic anhydride unit in the resin) and 188.1 g of distilled water were charged and stirred at a rotation speed of 300 rpm. During stirring, no sedimentation of the resin was observed at the bottom of the container, confirming that the resin was in a floating state. Therefore, while maintaining this state, the power of the heater was turned on after 10 minutes to heat. Then, the temperature in the system was maintained at 140° C., and the mixture was further stirred for 60 minutes. After that, the mixture was air-cooled to room temperature (about 25° C.) while stirring at a rotational speed of 300 rpm. The contents of the glass container are pressure-filtered (pneumatic pressure 0.2 MPa) through a 300-mesh stainless steel filter (wire diameter 0.035 mm, plain weave) to uniformly disperse the acid-modified polyolefin resin (A-1) in water. A solid (non-volatile component concentration of 25% by mass) was obtained. There was almost no residual resin on the filter after filtration.

<Production of liquid composition 1 for forming release layer>
100 parts by mass of an aqueous dispersion of acid-modified polyolefin resin (A-1) in terms of non-volatile components, and an aqueous solution of polyvinyl alcohol (“JT-05” manufactured by Nippon Acetate & Poval Co., Ltd., saponification rate 94.5%, degree of polymerization 500, non-volatile component concentration 8% by mass) is converted to 300 parts by mass in terms of non-volatile components, and an aqueous solution of an oxazoline group-containing compound as a cross-linking agent (Epocross “WS-700” manufactured by Nippon Shokubai Co., Ltd., non-volatile component concentration 25% by mass). 7 parts by mass in terms of non-volatile components were mixed, and water was added to adjust the final non-volatile component concentration to 6.0 mass %, thereby obtaining a liquid composition 1 for forming a release layer.

<Production of release film 1>
A resin composition containing amorphous silica particles having an average particle size of 2.3 μm and polyethylene terephthalate (PET, polymerization catalyst: antimony trioxide, intrinsic viscosity: 0.62, glass transition temperature: 78° C., melting point: 55° C.) prepared. The amount of amorphous silica particles in this resin composition was 0.08% by mass. This resin composition was melt-extruded at 280° C., brought into close contact with a casting drum by a T-die method-electrostatic pinning method, and quenched to obtain an unstretched film having a thickness of 600 μm. Subsequently, this unstretched film was stretched 3.5 times with a longitudinal stretching roll heated to 90° C. to obtain a longitudinally stretched film.

Liquid composition 1 for forming a release layer was applied to one side of the longitudinally stretched film using a reverse gravure coater so as to have a coating amount of 5 g/m ² (in terms of WET). After that, using a lateral stretching tenter, the longitudinally stretched film is stretched 4.5 times at 120 ° C., heat-treated at 230 ° C. for 10 seconds, cooled, wound up, and provided with a support film and a release layer. Film 1 was obtained. The thickness of the obtained release film 1 was 38 μm, and the thickness of the release layer was approximately 0.08 μm.

[Production Example 2. Production of release film 2]
<Production of liquid composition 2 for forming release layer>
Instead of 300 parts by mass of polyvinyl alcohol aqueous solution ("JT-05" manufactured by Japan VV-Poval Co., Ltd.) in terms of non-volatile components, 500 parts by mass of polyvinyl alcohol aqueous solution ("JL -05E", saponification rate 82.0%, degree of polymerization 500, non-volatile component concentration 8% by mass), the same as the step "Production of liquid composition 1 for forming release layer" in Production Example 1 A liquid composition 2 for forming a release layer was produced by the method.

<Production of release film 2>
A support was obtained by the same method as in the step “production of release film 1” in Production Example 1, except that liquid composition 2 for forming release layer was used instead of liquid composition 1 for forming release layer. A release film 2 comprising a body film and a release layer was obtained.

[Example 1]
(1-1. Production of resin sheet)
6 parts of bisphenol type epoxy resin ("ZX1059" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., epoxy equivalent of about 169, 1:1 mixture of bisphenol A type and bisphenol F type), bixylenol type epoxy resin ("YX4000HK" manufactured by Mitsubishi Chemical Corporation, Epoxy equivalent about 185) 9 parts, biphenyl type epoxy resin (Nippon Kayaku Co., Ltd. "NC3000L", epoxy equivalent 288) 21 parts, and phenoxy resin (Mitsubishi Chemical Co., Ltd. "YX7553BH30", cyclohexanone with a nonvolatile content of 30% by mass: 10 parts of a 1:1 solution of methyl ethyl ketone (MEK) was heated and dissolved in a mixed solvent of 20 parts of solvent naphtha and 5 parts of cyclohexanone with stirring to obtain a mixture. After cooling to room temperature, to this mixture, 6 parts of a triazine skeleton-containing cresol novolac curing agent (hydroxyl equivalent of 151, "LA-3018-50P" manufactured by DIC, 2-methoxypropanol solution of 50% non-volatile components), active Ester-based curing agent (manufactured by DIC "HPC-8000-65T", weight average molecular weight of about 2700, active group equivalent weight of about 223, non-volatile component 65% by weight toluene solution) 20 parts, amine-based curing accelerator (4-dimethyl Aminopyridine (DMAP), MEK solution of 5% by mass of non-volatile components) 2 parts, flame retardant ("HCA-HQ" manufactured by Sanko Co., Ltd., 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10 2 parts of 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 A. As the inorganic filler, spherical silica (“SOC2” manufactured by Admatechs Co., Ltd., average particle diameter 0.5 μm, specific surface area 5.8 m ² /g ) was used.

The resin varnish A is uniformly applied to the release layer side surface of the release film 1 obtained in Production Example 1 using a die coater, and dried at 80 ° C. to 120 ° C. (average 100 ° C.) for 6 minutes. Thus, a resin sheet 1 having a support film, a release layer and a resin composition layer in this order was obtained. The thickness of the resin composition layer of the resin sheet 1 was 40 μm.

(1-2. Lamination of resin composition layer and inner layer circuit board)
Both sides of a glass cloth-based epoxy resin double-sided copper clad laminate (copper foil thickness 18 μm, substrate thickness 0.8 mm, Panasonic Electric Works "R1515A") were immersed in MEC "CZ8100". The copper surface was roughened. Thus, an inner layer circuit board was obtained.

Resin sheet 1 was laminated on both sides of the inner layer circuit board using a batch-type vacuum pressure laminator (2-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 1 was bonded to the inner layer circuit board. Also, this lamination was carried out by depressurizing for 30 seconds to reduce the air pressure to 13 hPa or less, and then pressing under the press conditions of 100° C. and pressure of 0.74 MPa for 30 seconds.

(1-3. Curing of resin composition layer)
After lamination of the resin composition layer and the inner layer circuit board, the resin composition layer is heat-cured under the curing conditions of 130° C. for 30 minutes and then 170° C. for 30 minutes while the support film is still attached, to provide insulation. formed a layer. As a result, an evaluation sample including a support film, a release layer, an insulating layer, and an inner layer circuit board in this order was obtained. The thickness of the insulating layer on the inner layer circuit was 40 μm.

(1-4. Peeling of support film)
The evaluation sample was cooled to room temperature (approximately 25° C.) and the support film was peeled off to obtain an intermediate multilayer body and a peeled body.

(1-5. Oxidation treatment of insulating layer)
The intermediate multilayer body is immersed in a swelling liquid (Swelling Dip Securigant P containing diethylene glycol monobutyl ether from Atotech Japan Co., Ltd.) for 10 minutes at 60 ° C., and then a roughening liquid as an oxidizing agent (Concentrate from Atotech Japan Co., Ltd.). Immersed in Rate Compact P (KMnO ₄ : 60 g / L, NaOH: 40 g / L aqueous solution)) at 80 ° C. for 20 minutes, then neutralizing solution (Atotech Japan Co., Ltd. Reduction Shoryusin Securigant P) was immersed at 40° C. for 5 minutes to obtain a printed wiring board. The printed wiring board was dried at 80° C. for 30 minutes.

(1-6. Evaluation)
After the step (1-2) and before the step (1-3), the release film was partially peeled off. The surface of the release film that was in contact with the resin composition layer (that is, the surface of the release film on the release layer side) was observed with an SEM to confirm that there was a release layer on that surface. Also, the water contact angle θ1 of this surface was measured by the method described above.
Furthermore, the surface of the resin composition layer exposed by peeling off the release film (that is, the surface of the resin composition layer before curing on the release layer side) is observed with an SEM to confirm that there is no release layer on the surface. It was confirmed. Also, the water contact angle θ2 of this surface was measured by the method described above.

After step (1-4) and before step (1-5), the surface of the insulating layer exposed by peeling off the support film (that is, the release surface of the intermediate multilayer body) was observed with an SEM. , confirmed that there was a release layer on the surface. Also, the water contact angle θ3 of this surface was measured by the method described above.
Furthermore, the surface of the release body that was in contact with the insulating layer (that is, the release surface of the release body) was observed with an SEM, and it was confirmed that there was a release layer on that surface. Also, the water contact angle θ4 of this surface was measured by the method described above.

After the step (1-5), the arithmetic average roughness (Ra value) of the roughened surface (oxidized surface) of the insulating layer of the printed wiring board was measured by the method described above.

(1-7. Formation and evaluation of via holes)
A laser beam was irradiated to the support film side surface of the evaluation sample obtained in the step (1-3). Laser light irradiation was performed using a CO2 laser processing machine (LK-2K212/2C) manufactured by Via Mechanics Co., Ltd. under the conditions of a frequency of 2000 Hz, a pulse width of 3 μs, an output of 0.95 W, and the number of shots of 3. As a result, via holes penetrating through the support film, release layer and insulating layer were formed. The top diameter (diameter) of the via hole on the surface of the insulating layer was 50 μm, and the diameter of the via hole on the bottom surface of the insulating layer was 40 μm. The top diameter represents the diameter of the opening of the via hole. After that, the support film was peeled off to obtain an intermediate multilayer body comprising the inner layer circuit board, the insulating layer and the residual release layer. The obtained intermediate multilayer body was immersed in a swelling liquid, a roughening liquid and a neutralizing liquid under the same conditions as in step (1-5) to remove smears from the bottom of the via holes. The smear removability was evaluated in the following manner.

<Evaluation of Smear Removability>
The periphery of the bottom of the via hole was observed with a scanning electron microscope (SEM). From the obtained image, the maximum smear length from the wall surface at the bottom of the via hole was measured. Based on this maximum smear length, the smear removability was evaluated according to the following criteria.
"Good": The maximum smear length is less than 5 µm.
"Poor": The maximum smear length is 5 μm or more.

[Example 2]
In the same manner as in Example 1, except that the release film 2 obtained in Production Example 2 was used instead of the release film 1 obtained in Production Example 1, a printed wiring board was produced, and the water contact angle θ1 ~ Measurement of θ4 and measurement of arithmetic mean roughness (Ra value) were performed. Further, observation with SEM confirmed that there was a release layer on the surfaces where the water contact angles θ1, θ3 and θ4 were measured, and no release layer was present on the surface where the water contact angles θ2 were measured.

[Example 3]
Manufacture of printed wiring board by the same method as in Example 1, except that the curing conditions in the step of thermosetting the resin composition layer were changed to 100 ° C. for 30 minutes and 170 ° C. for 30 minutes. The water contact angles θ1 to θ4 and the arithmetic mean roughness (Ra value) were measured. Further, observation with SEM confirmed that there was a release layer on the surfaces where the water contact angles θ1, θ3 and θ4 were measured, and no release layer was present on the surface where the water contact angles θ2 were measured.

[Example 4]
A printed wiring board was manufactured by the same method as in Example 1, except that the curing conditions in the step of thermosetting the resin composition layer were changed to conditions of 170° C. for 30 minutes, and water contact angles θ1 to θ4 were measured. Measurement and measurement of arithmetic mean roughness (Ra value) were performed. Further, observation with SEM confirmed that there was a release layer on the surfaces where the water contact angles θ1, θ3 and θ4 were measured, and no release layer was present on the surface where the water contact angles θ2 were measured.

[Example 5]
Biphenyl type epoxy resin (epoxy equivalent about 290, Nippon Kayaku "NC000H") 30 parts, naphthalene type tetrafunctional epoxy resin (epoxy equivalent 162, DIC "HP-700") 5 parts, liquid bisphenol A type epoxy Resin (epoxy equivalent 180, "jER828EL" manufactured by Mitsubishi Chemical Corporation) 15 parts, and phenoxy resin (weight average molecular weight 35000, "YL7553BH30" manufactured by Mitsubishi Chemical Corporation, methyl ethyl ketone (MEK) solution of 30% by mass of non-volatile components) 2 parts, A mixed solvent of 8 parts of MEK and 8 parts of cyclohexanone was heated and dissolved with stirring to obtain a mixture. To this mixture, 32 parts of a triazine skeleton-containing phenol novolac curing agent (phenolic hydroxyl equivalent of about 124, "LA-7054" manufactured by DIC, MEK solution of 60% by mass of nonvolatile components), a phosphorus curing accelerator (Hokko Chemical Industry company "TBP-DA", tetrabutylphosphonium decanoate) 0.2 parts, inorganic filler 160 parts, polyvinyl butyral resin solution (weight average molecular weight 27000, glass transition temperature 105 ° C., Sekisui Chemical Co., Ltd. "KS- 1", a mixed solution of ethanol and toluene having a mass ratio of 1:1 containing 15% by mass of non-volatile components) were mixed and uniformly dispersed with a high-speed rotating mixer to prepare a resin varnish B. As the inorganic filler, spherical silica (“SOC2” manufactured by Admatechs Co., Ltd., average particle diameter 0.5 μm, specific surface area 5.8 m ² /g ) was used. The content of the inorganic filler (spherical silica) was 69.5% by mass when the total mass of the non-volatile components in the resin varnish B was 100% by mass.

Instead of the resin varnish A prepared in Example 1, the resin varnish B was used. Also, instead of the release film 1 obtained in Production Example 1, the release film 2 obtained in Production Example 2 was used. Furthermore, the curing conditions in the step of thermally curing the resin composition layer were changed to 100° C. for 30 minutes and 170° C. for 30 minutes. A printed wiring board was manufactured, the water contact angles θ1 to θ4 were measured, and the arithmetic average roughness (Ra value) was measured in the same manner as in Example 1 except for the above items. Further, observation with SEM confirmed that there was a release layer on the surfaces where the water contact angles θ1, θ3 and θ4 were measured, and no release layer was present on the surface where the water contact angles θ2 were measured.

[Example 6]
By the same method as in Example 1, except that the pressing conditions in the step of laminating the resin sheet 1 on both sides of the inner layer circuit board were changed to 100° C., 1 kgf/cm ² (0.098 MPa), and 30 seconds, A printed wiring board was manufactured, the water contact angles θ1 to θ4 were measured, and the arithmetic average roughness (Ra value) was measured. Further, observation with SEM confirmed that there was a release layer on the surfaces where the water contact angles θ1, θ3 and θ4 were measured, and no release layer was present on the surface where the water contact angles θ2 were measured.

[Example 7]
By the same method as in Example 1, except that the pressing conditions in the step of laminating the resin sheet 1 on both sides of the inner layer circuit board were changed to 80° C., pressure of 1 kgf/cm ² (0.098 MPa), and 30 seconds, A printed wiring board was manufactured, the water contact angles θ1 to θ4 were measured, and the arithmetic average roughness (Ra value) was measured. Further, observation with SEM confirmed that there was a release layer on the surfaces where the water contact angles θ1, θ3 and θ4 were measured, and no release layer was present on the surface where the water contact angles θ2 were measured.

[Comparative Example 1]
Production of a printed wiring board, measurement of water contact angles θ1 to θ4, and arithmetic mean roughness (Ra value) were performed in the same manner as in Example 1, except that the step of thermosetting the resin composition layer was not performed. was measured. In Comparative Example 1, since the resin composition layer was not heat-cured, the water contact angle θ3 was obtained from the surface of the uncured resin composition layer exposed by peeling off the support film (corresponding to the release surface). represents the water contact angle of In addition, the water contact angle θ4 is the surface of the peeled body obtained by peeling the support film without curing the resin composition layer (the surface corresponding to the peeled surface) that was in contact with the resin composition layer. represents the water contact angle. Moreover, it was confirmed by SEM observation that there was a release layer on the surfaces where the water contact angles θ1 and θ4 were measured, and no release layer was present on the surfaces where the water contact angles θ2 and θ3 were measured. Furthermore, in Comparative Example 1, the resin composition layer was damaged by the oxidation treatment, and the arithmetic mean roughness (Ra value) could not be measured.

[Comparative Example 2]
Instead of the release film 1 obtained in Production Example 1, a release film 3 ("AL-5" manufactured by Lintec Corporation; a multilayer film comprising a polyethylene terephthalate film as a support film and an alkyd-based release layer) was used. A printed wiring board was manufactured, the water contact angles θ1 to θ4 were measured, and the arithmetic mean roughness (Ra value) was measured in the same manner as in Example 1 except that the surface was not covered with the substrate. Moreover, it was confirmed by SEM observation that there was a release layer on the surfaces where the water contact angles θ1 and θ4 were measured, and no release layer was present on the surfaces where the water contact angles θ2 and θ3 were measured.

[result]
The results of the examples and comparative examples described above are shown in the table below. In the table below, the abbreviations have the following meanings.
θ1: Water contact angle on the release layer side surface of the release film peeled off before curing of the resin composition layer. This θ1 corresponds to the water contact angle _θD .
θ2: The water contact angle of the surface of the resin composition layer that appeared after the release film was peeled off before the resin composition layer was cured. This θ2 corresponds to the water contact angle _θB .
θ3: The water contact angle of the surface of the insulating layer that appeared when the support film was peeled off after the resin composition layer was cured. This θ3 corresponds to the water contact angle _θA .
θ4: Water contact angle of the surface of the peeled body including the support peeled off after curing of the resin composition layer, which was in contact with the insulating layer. This θ4 corresponds to the water contact angle _θC .
Ra: Arithmetic mean roughness of the roughened surface of the insulating layer after oxidation treatment.

REFERENCE SIGNS LIST 100 resin sheet 110 support 120 release layer 121 residual release layer 122 release release layer 130 resin composition layer 130U release layer side surface of resin composition layer before curing 140 hole 200 substrate 230 insulating layer (cured resin composition layer)
230U Roughened surface of insulating layer 240 Smear 250 Conductor layer 300 Intermediate multilayer body 300U Release surface of intermediate multilayer body 400 Stripping body 400D Stripping surface of stripping body 500 Printed wiring board

Claims (6)

A first step of preparing a resin sheet comprising a support, a release layer, and a resin composition layer in this order;
A second step of laminating the resin composition layer and the substrate;
a third step of curing the resin composition layer;
a fourth step of peeling off the support to obtain an intermediate multilayer body comprising the substrate, the resin composition layer, and at least part of the release layer in this order;
a fifth step of bringing an oxidizing agent into contact with the release layer side surface of the intermediate multilayer body, in this order ;
After the third step and before the fifth step, a sixth step of forming holes in the resin composition layer,
In the fifth step, the release layer of the intermediate multilayer body is removed by the oxidizing agent in contact with the release layer side surface of the intermediate multilayer body, and the resin composition layer A method for manufacturing a printed wiring board , comprising : 2. The method of manufacturing a printed wiring board according to claim 1 , wherein a part of said release layer adheres to said support peeled off in said fourth step. 3. The method of manufacturing a printed wiring board according to claim 1 , wherein in said fourth step, said release layer is destroyed inside said release layer. The method for producing a printed wiring board according to any one of claims 1 to 3 , wherein the surface of the intermediate multilayer body facing the release layer has a water contact angle of 75° or more and 110° or less. The difference between the water contact angle of the release layer side surface of the intermediate multilayer and the water contact angle of the release layer side surface of the release body including the support stripped in the fourth step. The method for producing a printed wiring board according to any one of claims 1 to 4 , wherein the absolute value of is 17° or less. The method for manufacturing a printed wiring board according to any one of claims 1 to 5 , comprising a seventh step of forming a conductor layer after the fifth step.

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