Method for manufacturing printed wiring board

Abstract

The present invention provides a manufacturing method of a printed wiring board which can improve the stain removal and reduce the roughness of the surface of the insulating layer. The manufacturing method of the printed wiring board comprises the following first to fifth processes in order: In the first process, a resin sheet is prepared, which comprises a support, a release layer, and a resin composition layer in order; in the second process, the resin composition layer is laminated with a substrate; in the third process, the resin composition layer is cured; in the fourth process, the support is peeled off to obtain an intermediate multilayer body, which comprises the substrate, the resin composition layer, and at least a part of the release layer in order; and in the fifth process, an oxidizing agent is contacted with the surface of the release layer side of the intermediate multilayer body.

Description

Technical Field

[0001] This invention relates to a method for manufacturing printed wiring boards. Background Technology

[0002] As a method for manufacturing printed wiring boards, a manufacturing method employing an alternating overlapping stacking of insulating and conductor layers is known. In manufacturing methods employing a stacking method, a resin composition layer containing a resin composition is typically cured to form an insulating layer. As described in Patent Document 1, such an insulating layer is sometimes formed using a resin sheet having a support and a resin composition layer.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent document 1: Japanese Patent Application Publication No. 2017-183411. Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] In the manufacturing process of printed circuit boards, sometimes openings are made in the insulating layer. For example, through-holes or other holes are sometimes formed in the insulating layer for purposes such as connecting conductor layers insulated by the insulating layer. When such openings are made, resin residue known as "smear" sometimes forms within the holes. Therefore, in most cases, after the opening process, a desmearing treatment is performed to remove the smear using an oxidizing agent. In the desmearing treatment, the oxidizing agent is typically brought into contact with the portion of the insulating layer where the holes are formed to remove the smear.

[0008] During decontamination treatment, oxidants may also come into contact with parts of the insulation layer other than the pores. The surface of the insulation layer that has come into contact with the oxidant typically undergoes roughening caused by the oxidant, resulting in a rougher surface shape. In particular, if conditions conducive to oxidation are used to effectively remove contaminants, roughening develops significantly, thus there is a tendency for the surface roughness of the insulation layer to increase.

[0009] In recent years, the demand for miniaturized wiring in printed circuit boards has been increasing. However, it is difficult to form fine wiring as a conductor layer on the surface of the insulating layer with high roughness. On the other hand, if the roughness caused by oxidants is reduced in order to reduce the roughness of the insulating layer surface, it may not be possible to remove contaminants sufficiently. As mentioned above, it has always been difficult to achieve both effective contaminant removal and wiring miniaturization. Therefore, it is desirable to develop a technology that can simultaneously improve contaminant removal performance and reduce the roughness of the insulating layer surface.

[0010] The present invention addresses the aforementioned issues and aims to provide a method for manufacturing a printed wiring board that simultaneously improves contamination removal and reduces the surface roughness of the insulating layer.

[0011] Technical solutions adopted to solve technical problems

[0012] The inventors conducted thorough research to solve the aforementioned problems. As a result, the inventors discovered that the aforementioned problems can be solved by employing a manufacturing method that sequentially includes the following steps, thereby completing the present invention: a step of preparing a resin sheet having a support, a release layer, and a resin composition layer in sequence; a step of laminating the resin composition layer to a substrate; a step of curing the resin composition layer; a step of peeling off the support to obtain an intermediate multilayer having at least a portion of a substrate, a resin composition layer, and a release layer in sequence; and a step of contacting an oxidant with the surface of the release layer side of the intermediate multilayer.

[0013] That is, the present invention includes the following:

[0014] [1] A method for manufacturing a printed wiring board, the method comprising the following first to fifth steps in sequence,

[0015] In the first step, a resin sheet is prepared, which sequentially comprises a support, a release layer, and a resin composition layer.

[0016] In the second process, the resin composition layer is laminated to the substrate;

[0017] In the third step, the resin composition layer is cured;

[0018] In the fourth step, the support body is peeled off to obtain an intermediate multilayer body, which sequentially comprises at least a portion of the substrate, the resin composition layer, and the release layer;

[0019] In the fifth step, the oxidant is brought into contact with the surface of the release layer side of the intermediate multilayer body;

[0020] [2] The method for manufacturing a printed wiring board according to [1] includes a sixth step after the third step and before the fifth step.

[0021] In the sixth step, pores (holes) are formed in the resin composition layer;

[0022] [3] The method for manufacturing a printed wiring board according to [1] or [2], wherein a portion of the release layer is attached to the support body that is peeled off in the fourth step;

[0023] [4] The method for manufacturing a printed wiring board according to any one of [1] to [3], wherein the fourth step includes: destroying the release layer inside the release layer;

[0024] [5] The method for manufacturing a printed wiring board according to any one of [1] to [4], wherein the water contact angle of the surface of the release layer side of the intermediate multilayer body is 75° or more and 110° or less;

[0025] [6] The method for manufacturing a printed wiring board according to any one of [1] to [5], wherein the absolute value of the difference between the water contact angle of the surface of the release layer side of the intermediate multilayer body and the water contact angle of the surface of the release layer side of the peeled body containing the support body peeled off in the fourth step is 17° or less;

[0026] [7] A method for manufacturing a printed wiring board according to any one of [1] to [6], wherein a seventh step of forming a conductor layer is included after the fifth step.

[0027] The effects of the invention

[0028] If the present invention is adopted, a method for manufacturing printed wiring boards can be provided that can simultaneously improve the removability of contaminants and reduce the surface roughness of the insulating layer.

[0029] Brief description of the attached diagram

[0030] Figure 1 This is a schematic cross-sectional view of the resin sheet prepared in the first step of the method for manufacturing a printed wiring board according to an embodiment of the present invention.

[0031] Figure 2 This is a schematic cross-sectional view of the resin sheet and substrate in the second step of the manufacturing method of the printed wiring board according to one embodiment of the present invention.

[0032] Figure 3 This is a schematic cross-sectional view of the resin sheet and substrate in the third step of a method for manufacturing a printed wiring board according to an embodiment of the present invention.

[0033] Figure 4 This is a schematic cross-sectional view of a resin sheet and a substrate with holes formed in the sixth step of a method for manufacturing a printed wiring board according to an embodiment of the present invention.

[0034] Figure 5 This is a schematic cross-sectional view illustrating the intermediate multilayer body and the peeled body obtained in the fourth step of the manufacturing method of the printed wiring board according to one embodiment of the present invention.

[0035] Figure 6This is a schematic cross-sectional view of a printed wiring board obtained by oxidizing an intermediate multilayer body in the fifth step of the manufacturing method of a printed wiring board according to an embodiment of the present invention.

[0036] Figure 7 This is a cross-sectional view schematically illustrating the seventh step of the manufacturing method of the printed wiring board according to the first embodiment of the present invention, in which a conductor layer is formed on the printed wiring board. Detailed Implementation

[0037] The present invention will now be described in detail with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples listed below, and may be implemented in any way without departing from the scope of the claims and their equivalents.

[0038] [1. Overview of the manufacturing method of printed wiring boards]

[0039] One embodiment of the present invention describes a method for manufacturing a printed wiring board, which sequentially includes:

[0040] The first step is to prepare a resin sheet, which sequentially comprises a support, a release layer, and a resin composition layer.

[0041] The second step involves laminating the resin composition layer onto the substrate.

[0042] The third step is to cure the resin composition layer;

[0043] The fourth step involves peeling off the support to obtain an intermediate multilayer body, which sequentially comprises at least a portion of a substrate, a resin composition layer, and a release layer; and

[0044] The fifth step involves bringing the oxidant into contact with the surface of the release layer side of the intermediate multilayer body.

[0045] In the following description, the cured resin composition layer in the third process is sometimes appropriately referred to as the "insulating layer". Furthermore, the surface of the intermediate multilayer on the release layer side is sometimes appropriately referred to as the "release surface" of the intermediate multilayer. The release surface of the intermediate multilayer corresponds to the surface on the side where the support is located before the fourth process. Therefore, the intermediate multilayer sequentially comprises a substrate, a resin composition layer, and a release surface in the thickness direction.

[0046] The method for manufacturing a printed wiring board according to one embodiment of the present invention may further include any combination of steps in addition to the first to fifth steps. For example, the method for manufacturing a printed wiring board may include a sixth step of forming holes in the insulating layer after the third step and before the fifth step. Furthermore, the method for manufacturing a printed wiring board may also include a seventh step of forming a conductor layer after the fifth step.

[0047] If the above-described printed wiring board manufacturing method is used, in the fifth step, contaminants can be effectively removed by an oxidizing agent, and excessive roughening of the release surface of the intermediate multilayer body caused by contact with the oxidizing agent can be suppressed. Therefore, by using the above-described printed wiring board manufacturing method, both improved contaminant removal and low surface roughness of the insulating layer can be achieved.

[0048] [2. First step: Preparation of resin sheets]

[0049] In the first step, resin sheets are prepared. Figure 1 This is a schematic cross-sectional view of the resin sheet 100 prepared in the first step of a method for manufacturing a printed wiring board according to an embodiment of the present invention. Figure 1 As shown, the resin sheet 100 sequentially comprises a support 110, a release layer 120, and a resin composition layer 130 in the thickness direction. Typically, the support 110 is in direct contact with the release layer 120, and the release layer 120 is in direct contact with the resin composition layer 130. The contact (or contact) configuration of the two components is a "direct" contact configuration, meaning that there are no other layers between these components.

[0050] [2.1. Support]

[0051] As a support, a plate-shaped or membrane-shaped component can be used. Examples of such supports include films made of plastic materials, metal foils, and release paper. Hereinafter, films made of plastic materials will sometimes be appropriately referred to as "plastic films." Of the above, plastic films and metal foils are preferred.

[0052] Examples of plastic materials that constitute plastic films include: polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); acrylic polymers such as polycarbonate (PC); polymethyl methacrylate (PMMA); cyclic polyolefins; triacetyl cellulose (TAC); polyether sulfides (PES); polyether ketones; and polyimides. These materials can be used individually or in combination. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred, and inexpensive polyethylene terephthalate is particularly preferred.

[0053] Plastic films may contain particles that can form fine protrusions to a degree that imparts slipperiness, without affecting the smoothness of the film surface.

[0054] When using metal foil as a support, examples of metal foils include copper foil and aluminum foil, with copper foil being preferred. Copper foil can be used as the support, either as a single metal such as copper or as an alloy of copper with other metals (e.g., tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.).

[0055] Regarding the support body, it can be treated with matte finish, corona discharge treatment, anti-static treatment, etc. on its surface.

[0056] The thickness of the support is not particularly limited, but it is preferably in the range of 5μm to 75μm, and more preferably in the range of 10μm to 60μm.

[0057] [2.2. Release Layer]

[0058] The release layer is formed by a release agent. The release agent facilitates the smooth peeling of the support. Specifically, compared to a support directly disposed on the resin composition layer, a support disposed on the resin composition layer via the release layer can be peeled off with less force. Here, the configuration of the support disposed on the resin composition layer is a "direct" configuration, meaning that there are no other layers between the resin composition layer and the support.

[0059] As a release agent contained in the release layer, a release agent that allows at least a portion of the release layer to remain in the resin composition layer after the support is peeled off in the fourth step can be used. Typically, a release agent containing a suitable resin is used. Examples of release agents include polyolefin resin release agents, polyurethane resin release agents, alkyd resin release agents, and silicone resin release agents. A single release agent can be used, or two or more can be used in combination. Polyolefin resin release agents are preferred.

[0060] As a polyolefin resin-based release agent, it is preferable to use a release agent that combines an acid-modified polyolefin resin, a crosslinking agent, and polyvinyl alcohol with a specific saponification rate. When using this polyolefin resin-based release agent, the release layer can undergo cohesive breakdown and separation, thus successfully obtaining the residual release layer described later. Therefore, significantly improved contamination removal properties and a lower surface roughness of the insulation layer can be achieved.

[0061] The preferred polyolefin resin release agent may contain an acid-modified polyolefin resin olefin component, preferably including at least one selected from ethylene, propylene, and butene. From the viewpoint of release properties, propylene is preferred. From the viewpoint of further improving release properties, 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, further preferably 95% by mass or more, and particularly preferably 99% by mass or more.

[0062] The acid-modifying component constituting the acid-modified polyolefin resin is preferably an unsaturated carboxylic acid component. Examples of unsaturated carboxylic acid components include: acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, butenoic acid, and other unsaturated carboxylic acids; as well as half-esters and half-amides of unsaturated dicarboxylic acids; etc. From the viewpoint of ensuring stable dispersion of the resin when preparing a liquid composition for forming a release layer, acrylic acid, methacrylic acid, maleic acid, and maleic anhydride are preferred, and acrylic acid, methacrylic acid, and maleic anhydride are particularly preferred.

[0063] Compared to 100% by mass acid-modified polyolefin resin, the amount of acid-modifying component in the acid-modified polyolefin resin is preferably 1% to 10% by mass, and more preferably 2% to 9% by mass. When the amount of acid-modifying component is above the lower limit of the range, the adhesion between the support and the release layer can be improved. Furthermore, when preparing the liquid composition for forming the release layer, it is easier to stably disperse the resin. On the other hand, when the amount of acid-modifying component is below the upper limit of the range, the release properties of the release layer can be improved.

[0064] From the viewpoint of improving the adhesion between the support and the release layer, acid-modified polyolefin resins may contain an olefinically unsaturated component whose side chain contains oxygen atoms. Examples of olefinically unsaturated components containing oxygen atoms in the side chain include, for example, esters of (meth)acrylic acid with an alcohol having 1 to 30 carbon atoms. From the perspective of ease of acquisition, esters of (meth)acrylic acid with an alcohol having 1 to 20 carbon atoms are preferred. Specific examples include: methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, octyl methacrylate, decyl methacrylate, lauryl methacrylate, dodecyl methacrylate, stearyl methacrylate, etc. From the perspective of adhesion to the support, methyl methacrylate, ethyl methacrylate, butyl methacrylate, hexyl acrylate, and octyl acrylate are more preferred, ethyl acrylate and butyl acrylate are even more preferred, and ethyl acrylate is particularly preferred. The term "(meth)acrylic acid" includes acrylic acid, methacrylic acid, and combinations thereof.

[0065] Relative to 100% by mass acid-modified polyolefin resin, the amount of olefinically unsaturated components containing oxygen atoms in the side chain of the acid-modified polyolefin resin is preferably 1% to 40% by mass, more preferably 2% to 35% by mass, even more preferably 3% to 30% by mass, and particularly preferably 6% to 18% by mass. When the amount of olefinically unsaturated components containing oxygen atoms in the side chain is above the lower limit of the range, the adhesion between the support and the release layer can be improved. On the other hand, when the amount of olefinically unsaturated components containing oxygen atoms in the side chain is below the upper limit of the range, the release properties of the release layer can be improved.

[0066] The components that make up acid-modified polyolefin resins are usually copolymerized within the acid-modified polyolefin resin. Examples of copolymerization states include random copolymerization, block copolymerization, and graft copolymerization (graft modification).

[0067] The melting point of the acid-modified polyolefin resin is preferably 80°C to 200°C, and more preferably 90°C to 150°C. When the melting point of the acid-modified polyolefin resin is above the lower limit of the range, the release properties of the release layer can be improved. On the other hand, when the melting point of the acid-modified polyolefin resin is below the upper limit of the range, the formation of the release layer can be facilitated.

[0068] The crosslinking agent that may be included in a preferred polyolefin resin release agent is preferably a compound containing multiple functional groups that can react with carboxyl groups within its molecule. Examples of preferred crosslinking agents include: polyfunctional epoxy compounds; polyfunctional isocyanate compounds; polyfunctional aziridine compounds; compounds containing carbodiimide groups; compounds containing oxazoline groups; phenolic resins; and amino resins such as urea compounds, melamine resins, and benzoguanamine resins. Among these, polyfunctional isocyanate compounds, melamine resins, urea compounds, polyfunctional epoxy compounds, compounds containing carbodiimide groups, and compounds containing oxazoline groups are preferred, especially compounds containing carbodiimide groups and compounds containing oxazoline groups. By using compounds containing oxazoline groups, the adhesion between the support and the release layer can be effectively improved, or the release properties of the release layer can be effectively improved.

[0069] Examples of multifunctional epoxy compounds include: polyepoxides and diepoxides. Examples of polyepoxides include: sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl (2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, and trimethylolpropane polyglycidyl ether. Examples of diepoxides 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, and poly-1,4-butanediol diglycidyl ether.

[0070] Examples of polyfunctional isocyanate compounds include: toluene diisocyanate, diphenylmethane-4,4'-diisocyanate, isophthalic diisocyanate, hexamethylene-1,6-diisocyanate, 1,6-diisocyanate-hexane, the adduct of toluene diisocyanate and glycerol, the adduct of toluene diisocyanate and trimethylolpropane, polyol-modified diphenylmethane-4,4'-diisocyanate, carbodiimide-modified diphenylmethane-4,4'-diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, 3,3'-dimethylbiphenyl-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, and isophthalic diisocyanate. Furthermore, end-capped isocyanate compounds obtained by blocking the isocyanate groups of these polyfunctional isocyanate compounds with appropriate compounds can be used as crosslinking agents. Examples of compounds that can be used for isocyanate group capping include bisulfite compounds, phenolic compounds containing sulfonic acid groups, alcohol compounds, lactam compounds, oxime compounds, and active methylene compounds. Commercially available polyfunctional isocyanate compounds include, for example, BASF's "Basonat HW-100".

[0071] Examples of polyfunctional aziridine compounds include N,N'-hexamethylene-1,6-bis(1-aziridineamide) and trimethylolpropane tri-β-aziridine propionate.

[0072] Examples of compounds containing a carbodiimide group include compounds having one or more carbodiimide groups in their molecules. Regarding carbodiimide compounds, crosslinking can be achieved by forming an ester with two carboxyl groups in the acid-modified portion of an acid-modified polyolefin resin within one carbodiimide moiety. Specific examples of compounds containing a carbodiimide group include: p-phenylenebis(2,6-dimethylcarbodiimide), tetramethylenebis(tert-butylcarbodiimide), cyclohexane-1,4-bis(methylene tert-butylcarbodiimide), and other compounds containing a carbodiimide group; polycarbodiimides as polymers containing a carbodiimide group; etc. Among these, polycarbodiimides are preferred from the perspective of ease of handling. Commercially available polycarbodiimides include the CARBODILITE series manufactured by Nisshinbo Co., Ltd.

[0073] Examples of compounds containing an oxazoline group include those having two or more oxazoline groups in their molecules. In oxazoline compounds, crosslinking can be achieved by forming an amide ester with one carboxyl group in the acid-modified portion of an acid-modified polyolefin resin from each of the two oxazoline moieties. Such oxazoline-containing compounds can be manufactured by homopolymerization of an addition-polymerizable oxazoline-containing monomer or copolymerization of an addition-polymerizable oxazoline-containing monomer with any other monomer. Examples of addition-polymerizable oxazoline-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, and 2-isopropenyl-5-ethyl-2-oxazoline. Among these, 2-isopropenyl-2-oxazoline is preferred because it is readily available industrially. Examples of any monomer include: alkyl acrylates, alkyl methacrylates (as alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, 2-ethylhexyl, cyclohexyl), and other (meth)acrylate compounds; unsaturated carboxylic acid compounds such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, butenoic acid, styrene sulfonic acid, and their salts (e.g., sodium salts, potassium salts, ammonium salts, tertiary amine salts, etc.); unsaturated nitrile compounds such as acrylonitrile and methacrylonitrile; acrylamide, methacrylamide, N-alkylacrylamide, and N-alkylmethylacrylamide. Unsaturated amide compounds such as N,N-dialkylacrylamide and N,N-dialkylmethylacrylamide (as alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, 2-ethylhexyl, cyclohexyl); 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; halogenated α,β-unsaturated aliphatic monomer compounds such as vinyl chloride, vinylidene chloride, and vinyl fluoride; and α,β-unsaturated aromatic monomers such as styrene and α-methylstyrene. Among these, polymers containing oxazoline groups are preferred from the perspective of ease of handling. Commercially available oxazoline-containing polymers include, for example, the EPOCROS series manufactured by Nippon Shokubai Co., Ltd.

[0074] Examples of phenolic resins include, for instance, methyl phenolic resins and / or linear phenolic resins that can be synthesized from phenol; bisphenol A, p-tert-butylphenol, octylphenol, p-cumylphenol and other alkylphenols; p-phenylphenol; cresol and the like.

[0075] Examples of urea compounds include dihydroxymethylurea, dihydroxymethylethyleneurea, dihydroxymethylpropenyleneurea, tetrahydroxymethylethynylurea, and 4-methoxy-5-dimethylpropenylene-hydroxymethylurea.

[0076] Examples of melamine resins include compounds having one or more functional groups selected from imino, hydroxymethyl, and alkoxymethyl groups in one molecule. Examples of alkoxymethyl groups include methoxymethyl and butoxymethyl groups. Specific examples of melamine resins include imino-type methylated melamine resins, hydroxymethyl-type melamine resins, hydroxymethyl-type methylated melamine resins, and fully alkyl-type methylated melamine resins. Hydroxymethylated melamine resins are particularly preferred. Furthermore, to promote the thermosetting of melamine resins, it is preferable to use an acidic catalyst such as p-toluenesulfonic acid.

[0077] Examples of benzoguanidine resins include tris(hydroxymethyl)benzoguanidine, hexa(hydroxymethyl)benzoguanidine, trimethoxymethylbenzoguanidine, and hexa(methoxymethyl)benzoguanidine.

[0078] By using a crosslinking agent, the components of the release layer are crosslinked, thus improving its release properties. Furthermore, crosslinking increases the cohesive strength of the release layer, making it more prone to cohesive failure. Additionally, it improves the water resistance of the release layer.

[0079] Relative to 100 parts by weight of acid-modified polyolefin resin, the amount of crosslinking agent is preferably 1 part by weight or more, more preferably 2 parts by weight or more, preferably 20 parts by weight or less, more preferably 15 parts by weight or less, and particularly preferably 10 parts by weight or less. When the amount of crosslinking agent is above the lower limit of the range, the cohesiveness of the release layer can be improved, thus improving the adhesion between the support and the release layer, or improving the release properties of the release layer. On the other hand, when the amount of crosslinking agent is below the upper limit of the range, the release properties of the release layer can be improved, or the thickening of the liquid composition used to manufacture the release layer can be suppressed, thereby improving stability.

[0080] Preferred polyolefin resin release agents may contain polyvinyl alcohol with 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, more preferably 99% or less, more preferably less than 98%, further preferably less than 96%, and particularly preferably less than 95%. When the saponification rate of polyvinyl alcohol is above the lower limit of the range, it can stabilize the liquid composition used to manufacture the release layer and improve the productivity of the release layer. Furthermore, when the saponification rate of polyvinyl alcohol is below the upper limit of the range, it can suppress the formation of tiny non-planar shapes with heights of tens to hundreds of nanometers on the surface of the release layer. Therefore, the surface shape of the resin composition layer can be smoothed. In addition, it can suppress warping of the release layer in high humidity environments or suppress peeling static electricity in low humidity environments.

[0081] When using preferred polyolefin resin-based release agents, the release layer is typically manufactured using an aqueous solvent. Therefore, from the viewpoint of ease of mixing with aqueous solvents, polyvinyl alcohol is preferably water-soluble.

[0082] Commercially available products can be used as polyvinyl alcohol. Examples of polyvinyl alcohol include: "JP-15", "JT-05", "JL-05E", "JM-33", "JM-17", "JF-05", and "JF-10" of "J-POVAL" manufactured by JAPAN VAM & POVAL CO.,LTD.; and "PVA-CST", "PVA-624", "PVA-203", "PVA-220", and "PVA-405" of "KURARAY POVAL" manufactured by Kuraray Co., Ltd.

[0083] The amount of polyvinyl alcohol relative to 100 parts by weight of acid-modified polyolefin resin is preferably 10 parts by weight or more, more preferably 100 parts by weight or more, even more preferably 210 parts by weight or more, particularly preferably 300 parts by weight or more, preferably 1000 parts by weight or less, more preferably 800 parts by weight or less, and particularly preferably 600 parts by weight or less. When the amount of polyvinyl alcohol is above the lower limit of the range, the release properties of the release layer can be effectively improved. On the other hand, when the amount of polyvinyl alcohol is below the upper limit of the range, the viscosity of the liquid composition used to form the release layer can be reduced, and the aforementioned non-planar shape can be suppressed on the surface of the release layer.

[0084] Preferred polyolefin resin release agents may contain lubricants. Examples of lubricants include: inorganic particles 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, carbon black, and molybdenum disulfide; organic particles such as acrylic crosslinked polymers, styrene crosslinked polymers, silicone resins, fluoropolymers, benzoguanamine resins, phenolic resins, nylon resins, and polyethylene wax; surfactants; etc.

[0085] When using a preferred polyolefin resin-based release agent to form a release layer, a layer comprising the release agent and a solvent is typically formed on a support, and then dried, stretched, and heat-treated as needed. In this case, an aqueous solvent is preferred. For information on release layers using such a preferred polyolefin resin-based release agent, refer to International Publication No. 2018 / 056276.

[0086] The thickness of the release layer is not particularly limited, but it is preferably 0.01 μm or more, more preferably 0.05 μm or more, more preferably 1.00 μm or less, and more preferably 0.50 μm or less. When the thickness of the release layer is above the lower limit of the range, the release layer can be smoothly separated internally by peeling off the support in the fourth process. Furthermore, when the thickness of the release layer is below the upper limit of the range, the thickness of the release layer on the release surface of the intermediate multilayer body obtained in the fourth process can be reduced, thus suppressing release layer residue after the fifth process.

[0087] The thickness of the release layer was measured using a curve fitting method with an Optical Nano Gauge C12562 manufactured by Hamamatsu Photonics Co., Ltd.

[0088] [2.3. Resin Composition Layer]

[0089] The resin composition layer is formed from a curable resin composition. The resin composition contained in the resin composition layer is typically a thermosetting resin composition. Therefore, the resin composition usually contains a thermosetting resin.

[0090] The type of thermosetting resin can be appropriately selected according to the required properties of the insulating layer of the printed wiring board. As a thermosetting resin, it is particularly preferable to use an epoxy resin in combination with a curing agent that can react with the epoxy resin.

[0091] Examples of epoxy resins include: xylenol-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, triphenol-type epoxy resin, naphthol novolak-type epoxy resin, phenol novolak-type epoxy resin, tert-butylcatechol-type epoxy resin, naphthalene-type epoxy resin, naphthol-type epoxy resin, anthracene-type epoxy resin, glycidylamine-type epoxy resin, glycidyl ester-type epoxy resin, and cresol novolak-type epoxy resin. Epoxy resins include novolak type, biphenyl type, linear aliphatic epoxy resin, butadiene-based epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin, spirocyclic epoxy resin, cyclohexane type epoxy resin, cyclohexanediethanol type epoxy resin, naphthyl ether type epoxy resin, trimethylolpropionic acid type epoxy resin, tetraphenylethane type epoxy resin, etc. Epoxy resins can be used alone or in combination of two or more types.

[0092] For the resin composition, it is preferable to include an epoxy resin having two or more epoxy groups per molecule as the epoxy resin. The proportion of epoxy resin having two or more epoxy groups per molecule is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more, relative to 100% by mass of the non-volatile components of the epoxy resin.

[0093] Epoxy resins include epoxy resins that are liquid at 20°C (hereinafter referred to as "liquid epoxy resins") and epoxy resins that are solid at 20°C (hereinafter referred to as "solid epoxy resins"). The resin composition may contain only liquid epoxy resin or only solid epoxy resin, and preferably a combination of both. By using a combination of liquid and solid epoxy resins, the flexibility of the resin composition can be improved, or the tensile strength of the cured resin composition can be improved.

[0094] As a liquid epoxy resin, it is preferable to be a liquid epoxy resin having two or more epoxy groups per molecule, and more preferably an aromatic liquid epoxy resin having two or more epoxy groups per molecule. Here, "aromatic" epoxy resin refers to an epoxy resin having an aromatic ring within its molecule.

[0095] As liquid epoxy resins, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, phenolic varnish type epoxy resin, alicyclic epoxy resin with an ester skeleton, cyclohexane type epoxy resin, cyclohexanediol type epoxy resin, glycidylamine type epoxy resin, and epoxy resin with a butadiene structure are preferred. One type of liquid epoxy resin can be used alone, or two or more types can be used in combination. Among these, bisphenol A type epoxy resin, bisphenol F type epoxy resin, and cyclohexane type epoxy resin are more preferred, and bisphenol A type epoxy resin and bisphenol F type epoxy resin are particularly preferred.

[0096] Specific examples of liquid epoxy resins include: DIC Corporation's "HP4032", "HP4032D", and "HP4032SS" (naphthalene-type epoxy resin); Mitsubishi Chemical Corporation's "828US", "jER828EL", "825", and "EPIKOTE 828EL" (bisphenol A type epoxy resin); Mitsubishi Chemical Corporation's "jER807" and "1750" (bisphenol F type epoxy resin); Mitsubishi Chemical Corporation's "jER152" (phenolic varnish type epoxy resin); Mitsubishi Chemical Corporation's "630" and "630LSD" (glycidylamine type epoxy resin); Nippon Steel & Sumitomo Metal Chemicals Co., Ltd.'s "ZX1059" (a mixture of bisphenol A and bisphenol F type epoxy resins); and Nagase. ChemteX Corporation's "EX-721" (glycidyl ester type epoxy resin), Daicel Corporation's "CELLOXIDE 2021P" (alicyclic epoxy resin with ester skeleton), Daicel Corporation's "PB-3600" (epoxy resin with butadiene structure), and Nippon Steel & Sumitomo Chemical Co., Ltd.'s "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane type epoxy resin), etc.

[0097] As a solid epoxy resin, it is preferable to be a solid epoxy resin having three or more epoxy groups per molecule, and more preferably an aromatic solid epoxy resin having three or more epoxy groups per molecule.

[0098] As solid epoxy resins, the preferred types are xylenol-type epoxy resins, naphthalene-type epoxy resins, naphthalene-type tetrafunctional epoxy resins, cresol-phenolic varnish-type epoxy resins, dicyclopentadiene-type epoxy resins, triphenol-type epoxy resins, naphthol-type epoxy resins, biphenyl-type epoxy resins, naphthylene ether-type epoxy resins, anthracene-type epoxy resins, bisphenol A-type epoxy resins, bisphenol AF-type epoxy resins, and tetraphenylethane-type epoxy resins. A single solid epoxy resin can be used alone, or two or more can be used in combination. Among these, xylenol-type epoxy resins, naphthalene-type tetrafunctional epoxy resins, and biphenyl-type epoxy resins are more preferred.

[0099] Specific examples of solid epoxy resins include: DIC Corporation's "HP4032H" (naphthalene-type epoxy resin), DIC Corporation's "HP-4700" and "HP-4710" (naphthalene-type tetrafunctional epoxy resins), DIC Corporation's "N-690" (cresol phenolic varnish type epoxy resin), DIC Corporation's "HP-695" (cresol phenolic varnish type epoxy resin), and DIC Corporation's "HP-7200," "HP-7200HH," and "HP-7200..." H (dicyclopentadiene type epoxy resin), DIC Corporation's "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000" (naphthyl ether type epoxy resin), Nippon Kayaku Co., Ltd.'s "EPPN-502H" (triphenol type epoxy resin), Nippon Kayaku Co., Ltd.'s "NC7000L" (naphthol phenolic varnish type epoxy resin), Nippon Kayaku Co., Ltd.'s "NC3000H", "N C3000, NC3000L, and NC3100 (biphenyl type epoxy resin); Nippon Steel & Sumitomo Chemical Co., Ltd.'s "ESN475V" (naphthalene type epoxy resin); Nippon Steel & Sumitomo Chemical Co., Ltd.'s "ESN485" (naphthol phenolic varnish type epoxy resin); Mitsubishi Chemical Co., Ltd.'s "YX4000" and "YL6121" (biphenyl type epoxy resin); Mitsubishi Chemical Co., Ltd.'s "YX4000H" and "YX4000HK" (bixylenol type epoxy resin); Mitsubishi Chemical... The company manufactures "YX8800" (anthracene-type epoxy resin), "PG-100" and "CG-500" (Osaka Gas Chemical Co., Ltd.), "YL7760" and "YX7760" (bisphenol AF-type epoxy resin) (Mitsubishi Chemical Co., Ltd.), "YL7800" (fluorene-type epoxy resin) (Mitsubishi Chemical Co., Ltd.), "jER1010" (solid bisphenol A-type epoxy resin) (Mitsubishi Chemical Co., Ltd.), and "jER1031S" (tetraphenylethane-type epoxy resin), etc.

[0100] When using a combination of liquid and solid epoxy resins, the mass ratio (liquid epoxy resin: solid epoxy resin) is preferably 1:1 to 1:20, more preferably 1:1.5 to 1:15, and particularly preferably 1:2 to 1:13. When the mass ratio of liquid to solid epoxy resin is within the aforementioned range, the resin composition layer can have moderate adhesion and sufficient flexibility, thus improving workability (processability). Furthermore, an insulating layer with sufficient tensile strength can generally be obtained.

[0101] The epoxy equivalent of the epoxy resin is preferably 50 g / eq. to 5000 g / eq., more preferably 50 g / eq. to 3000 g / eq., even more preferably 80 g / eq. to 2000 g / eq., and even more preferably 110 g / eq. to 1000 g / eq. Within this range of epoxy equivalent, the crosslinking density of the cured resin composition becomes sufficient, resulting in an insulating layer with low surface roughness. Epoxy equivalent is the mass of resin containing 1 equivalent of epoxy groups. This epoxy equivalent can be determined according to JIS K7236.

[0102] The weight-average molecular weight (Mw) of epoxy resin is preferably 100–5000, more preferably 250–3000, and even more preferably 400–1500.

[0103] The weight-average molecular weight of the resin can be determined by gel permeation chromatography (GPC) as a conversion value to polystyrene. Specifically, for the weight-average molecular weight, an LC-9A / RID-6A instrument manufactured by Shimadzu Corporation can be used as the measuring device, a Shodex K-800P / K-804L / K-804L column manufactured by Showa Denko Corporation can be used as the column, chloroform or the like can be used as the mobile phase, the column temperature can be set to 40°C, and the weight-average molecular weight can be calculated using a calibration curve of standard polystyrene.

[0104] From the viewpoint of obtaining an insulating layer exhibiting good mechanical strength and insulation reliability, the amount of epoxy resin in the resin composition is preferably 1% by mass or more, more preferably 5% by mass or more, further 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, relative to 100% by mass of non-volatile components in the resin composition.

[0105] Examples of curing agents include reactive ester curing agents, phenolic curing agents, naphthol curing agents, benzoxazine curing agents, cyanate ester curing agents, carbodiimide curing agents, amine curing agents, and acid anhydride curing agents. A single curing agent can be used alone, or two or more can be used in combination.

[0106] As an active ester curing agent, a compound having one or more active ester groups per molecule can be used. Among these, compounds having two or more highly reactive ester groups per molecule, such as phenolic esters, thiophenolic esters, N-hydroxyamine esters, and heterocyclic hydroxyl esters, are preferred. This active ester curing agent is preferably a compound obtained through a condensation reaction of a carboxylic acid compound and / or a thiocarboxylic acid compound with a hydroxyl compound and / or a thiol compound. Particularly from the viewpoint of improved heat resistance, an active ester curing agent obtained from a carboxylic acid compound and a hydroxyl compound is preferred, and an active ester curing agent obtained from a carboxylic acid compound and a phenolic compound and / or a naphthol compound is even more preferred.

[0107] 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.

[0108] Examples of phenolic or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthol, 1,6-dihydroxynaphthol, 2,6-dihydroxynaphthol, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucinol, pyroglucinol, dicyclopentadiene-type diphenol compounds, and phenol novolak resins. Here, "dicyclopentadiene-type diphenol compounds" refers to diphenol compounds obtained by condensing one molecule of dicyclopentadiene with two molecules of phenol.

[0109] Preferred examples of reactive ester curing agents include reactive ester curing agents containing a dicyclopentadiene-type diphenol structure, reactive ester curing agents containing a naphthalene structure, reactive ester curing agents containing an acetylated derivative of phenolic varnish resin, and reactive ester curing agents containing a benzoyl derivative of phenolic varnish resin. More preferably, reactive ester curing agents containing a naphthalene structure or reactive ester curing agents containing a dicyclopentadiene-type diphenol structure are preferred. "Dicyclopentadiene-type diphenol structure" refers to a divalent structural unit formed from a phenylene-dicyclopentylene-phenylene group.

[0110] Commercially available reactive ester curing agents include, for example, those containing a dicyclopentadiene-type diphenol structure such as "EXB9451", "EXB9460", "EXB9460S", "HPC-8000", "HPC-8000H", "HPC-8000-65T", "HPC-8000H-65TM", "EXB-8000L", "HPC-8000L-65TM", and "EXB-8150-65T" (manufactured by DIC Corporation). Reactive ester curing agents containing a naphthalene structure include "EXB9416-70BK", "EXB-8150-65T", "EXB-8100L-65T", and "EXB-8150". Examples of active ester curing agents containing phenolic varnish resins include L-65T (manufactured by DIC Corporation), DC808 (manufactured by Mitsubishi Chemical Corporation), YLH1026 (manufactured by Mitsubishi Chemical Corporation), DC808 (manufactured by Mitsubishi Chemical Corporation), YLH1026 (manufactured by Mitsubishi Chemical Corporation), YLH1030 (manufactured by Mitsubishi Chemical Corporation), and YLH1048 (manufactured by Mitsubishi Chemical Corporation).

[0111] From the viewpoint of heat resistance and water resistance, curing agents with a linear phenolic structure (novolak structure) are preferred as phenolic and naphthol curing agents. Furthermore, from the viewpoint of the adhesion between the conductor layer and the insulating layer, nitrogen-containing phenolic curing agents are preferred, and phenolic curing agents containing a triazine backbone are even more preferred.

[0112] Specific examples of phenolic and naphthol curing agents include: MEH-7700, MEH-7810, and MEH-7851 manufactured by Meiwa Kasei Corporation; NHN, CBN, and GPH manufactured by Nippon Kayaku Co., Ltd.; SN170, SN180, SN190, SN475, SN485, SN495, SN495V, SN375, and SN-395 manufactured by Nippon Steel & Sumitomo Metal Chemicals Co., Ltd.; and TD-2090, LA-7052, LA-7054, LA-1356, LA-3018-50P, and EXB-9500 manufactured by DIC Corporation.

[0113] Specific examples of benzoxazine curing agents include "JBZ-OP100D" and "ODA-BOZ" manufactured by JFE Chemical Co., Ltd., "HFB2006M" manufactured by Showa Polymer Co., Ltd., and "Pd" and "Fa" manufactured by Shikoku Chemical Industry Co., Ltd.

[0114] Examples of cyanate ester curing agents include: bisphenol A dicyanate, polyphenol cyanate, oligomeric (3-methylene-1,5-phenylene cyanate), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethylene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate-phenylpropane), 1,1-bis(4-cyanate-phenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanate-phenyl-1-(methylethylene))benzene, bis(4-cyanate-phenyl) sulfide, and bis(4-cyanate-phenyl) ether, etc., difunctional cyanate ester resins, polyfunctional cyanate ester resins derived from phenolic varnish resins and cresol varnish resins, etc., and prepolymers obtained by triazinizing a portion of these cyanate ester resins, etc. Specific examples of cyanate ester curing agents include: "PT30" and "PT60" (phenolic varnish type multifunctional cyanate ester resins), "ULL-950S" (multifunctional cyanate ester resins), "BADCy" (bisphenol A dicyanate), "BA230", and "BA230S75" (prepolymers in which part or all of the bisphenol A dicyanate is triazineized to form a trimer).

[0115] Specific examples of carbodiimide curing agents include "V-03" and "V-07" manufactured by Nisshinbo Chemical Co., Ltd.

[0116] As amine curing agents, examples include curing agents having one or more amino groups within one molecule, such as aliphatic amines, polyether amines, alicyclic amines, and aromatic amines. Aromatic amines are preferred. Amine curing agents are preferably primary or secondary amines, and more preferably primary amines. Specific examples of amine curing agents include: 4,4'-methylenebis(2,6-dimethylaniline), diphenyl diamino sulfone, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, m-phenylenediamine, m-xylenediamine, 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-diphenylmethanediamine, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, bis(4-(3-aminophenoxy)phenyl)sulfone, etc. Amine curing agents can be commercially available, such as "KAYABOND C-200S", "KAYABOND C-100", "KAYAHARD AA", "KAYAHARD A-B", and "KAYAHARD AS" manufactured by Nippon Kayaku Co., Ltd., and "EPICURE W" manufactured by Mitsubishi Chemical Co., Ltd., etc.

[0117] As anhydride-based curing agents, examples include curing agents having one or more anhydride groups within a single molecule. Specific examples of anhydride-based curing agents include: phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride, and pyromellitic tetramethyl... Anhydrides include polymeric anhydrides such as benzophenone tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenyl sulfone tetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan-1,3-dione, ethylene glycol bis(triphenylene trihydride), and styrene-maleic acid resin copolymerized with styrene and maleic acid. Commercially available anhydride curing agents include "HNA-100" and "MH-700" manufactured by Shin Nippon Rika Co., Ltd.

[0118] The curing agent preferably contains an active ester-based curing agent. When using an active ester-based curing agent, the content of the active ester-based curing agent relative to 100% by mass of the curing agent is preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, typically less than 100% by mass, preferably less than 98% by mass, more preferably less than 96% by mass, and even more preferably less than 94% by mass. From the viewpoint that it can further reduce surface roughness and reduce the dielectric loss tangent, it is preferable to use an active ester-based curing agent.

[0119] The amount of curing agent in the resin composition is preferably 1% or more by mass relative to 100% by mass of the non-volatile components in the resin composition, more preferably 3% or more by mass, further preferably 5% or more by mass, preferably 70% or less by mass, more preferably 60% or less by mass, and further preferably 50% or less by mass.

[0120] When the number of epoxy groups in the epoxy resin is set to 1, the number of active groups in the curing agent is preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.3 or more, preferably 3 or less, more preferably 2.0 or less, and even more preferably 1.6 or less. "The number of epoxy groups in the epoxy resin" refers to the sum of all 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 in the curing agent" refers to the sum of all 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 in the curing agent is within the range when the number of epoxy groups in the epoxy resin is set to 1, the heat resistance of the cured resin composition is generally improved.

[0121] The resin composition contained in the resin composition layer may include thermoplastic resins as needed. Examples of thermoplastic resins include phenoxy resins, polyvinyl acetal resins, polyolefin resins, polybutadiene resins, polyimide resins, polyamide-imide resins, polyether-imide resins, polysulfone resins, polyethersulfone resins, polyphenylene ether resins, polycarbonate resins, polyetheretherketone resins, and polyester resins. A single thermoplastic resin may be used alone, or two or more may be used in combination. From the viewpoint of obtaining an insulating layer with low surface roughness and particularly excellent adhesion to the conductor layer, phenoxy resin is preferred.

[0122] Examples of phenoxy resins include those having one or more skeletons selected from the following: bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenol acetylbenzene skeleton, linear phenolic (novolak) skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, terpene skeleton, and trimethylcyclohexane skeleton. The terminal group of the phenoxy resin can be any functional group such as a phenolic hydroxyl group or an epoxy group. Specific examples of phenoxy resins include "1256" and "4250" (both phenoxy resins containing a bisphenol A backbone) manufactured by Mitsubishi Chemical Corporation, "YX8100" (phenoxy resin containing a bisphenol S backbone) manufactured by Mitsubishi Chemical Corporation, "YX6954" (phenoxy resin containing a bisphenol acetylbenzene backbone) manufactured by Mitsubishi Chemical Corporation, "FX280" and "FX293" manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd., and "YL7500BH30", "YX6954BH30", "YX7553", "YX7553BH30", "YL7769BH30", "YL6794", "YL7213", "YL7290" and "YL7482" manufactured by Mitsubishi Chemical Corporation.

[0123] Examples of polyvinyl alcohol acetal resins include polyvinyl alcohol formaldehyde resin and polyvinyl alcohol butyral resin, with polyvinyl alcohol butyral resin being preferred. Specific examples of polyvinyl alcohol acetal resins include "Denka Butyral 4000-2", "Denka Butyral 5000-A", "Denka Butyral 6000-C", and "Denka Butyral 6000-EP" manufactured by Denka Kogyo Co., Ltd., and the S-LEC BH series, BX series (e.g., BX-5Z), KS series (e.g., KS-1), BL series, and BM series manufactured by Sekisui Chemicals Co., Ltd.

[0124] Specific examples of polyimide resins include "RIKACOAT SN20" and "RIKACOAT PN20" manufactured by Shin Nippon Rika Co., Ltd. Other specific examples of polyimide resins include linear polyimides (the polyimide described in Japanese Patent Application Publication No. 2006-37083) obtained by reacting difunctional hydroxyl-terminated polybutadiene, diisocyanate compounds, and tetrabasic anhydrides, and modified polyimides such as polyimides containing a polysiloxane backbone (the polyimides described in Japanese Patent Application Publication Nos. 2002-12667 and 2000-319386, etc.).

[0125] Specific examples of polyamide-imide resins include "VYLOMAXHR11NN" and "VYLOMAXHR16NN" manufactured by Toyobo Co., Ltd. Specific examples of polyamide-imide resins also include modified polyamide-imides such as "KS9100" and "KS9300" (polyamide-imide containing a polysiloxane backbone) manufactured by Hitachi Chemical Co., Ltd.

[0126] Specific examples of polyethersulfone resins include "PES5003P" manufactured by Sumitomo Chemical Co., Ltd.

[0127] Specific examples of polyphenylene ether resins include the low-polyphenylene ether-styrene resin "OPE-2St 1200" manufactured by Mitsubishi Gas Chemical Co., Ltd.

[0128] Specific examples of polysulfone resins include polysulfones such as "P1700" and "P3500" manufactured by Solvay Advanced Polymers.

[0129] 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, more preferably 70,000 or less, more preferably 60,000 or less, and particularly preferably 50,000 or less. When the weight-average molecular weight (Mw) of the thermoplastic resin is within the aforementioned range, the dielectric constant and coefficient of linear thermal expansion of the cured resin composition can generally be reduced, or the mechanical strength of the cured product can be increased.

[0130] When using thermoplastic resins, the amount of thermoplastic resin in the resin composition is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, further preferably 0.3% by mass or more, preferably 15% by mass or less, more preferably 10% by mass or less, and further preferably 5% by mass or less, relative to 100% by mass of the non-volatile components in the resin composition. When the amount of thermoplastic resin is within the stated range, the dielectric constant and coefficient of linear thermal expansion of the cured resin composition can generally be reduced, or the mechanical strength of the cured product can be increased.

[0131] The resin composition contained in the resin composition layer may include a curing accelerator as needed. Examples of curing accelerators include phosphorus-based curing accelerators, amine-based curing accelerators, imidazole-based curing accelerators, guanidine-based curing accelerators, and metal-based curing accelerators. A single curing accelerator may be used alone, or two or more may be used in combination. Phosphorus-based curing accelerators and amine-based curing accelerators are preferred.

[0132] Examples of phosphorus curing accelerators include triphenylphosphine, phosphonium borate compounds, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate, etc., with triphenylphosphine and tetrabutylphosphonium decanoate being preferred.

[0133] Examples of amine curing accelerators include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine (DMAP), benzyl dimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene, with 4-dimethylaminopyridine and 1,8-diazabicyclo(5,4,0)-undecene being preferred.

[0134] Examples of imidazole curing accelerators include: 2-methylimidazolium, 2-undecylimidazolium, 2-heptadecylimidazolium, 1,2-dimethylimidazolium, 2-ethyl-4-methylimidazolium, 1,2-dimethylimidazolium, 2-ethyl-4-methylimidazolium, 2-phenylimidazolium, 2-phenyl-4-methylimidazolium, 1-benzyl-2-methylimidazolium, 1-benzyl-2-phenylimidazolium, 1-cyanoethyl-2-methylimidazolium, 1-cyanoethyl-2-undecylimidazolium, 1-cyanoethyl-2-ethyl-4-methylimidazolium, 1-cyanoethyl-2-phenylimidazolium, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-triazine, 2,4- Diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-triazine isocyanuric acid adduct, 2-phenylimidazolyl isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazolium, 2-phenyl-4-methyl-5-hydroxymethylimidazolium, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, 2-phenylimidazoline and other imidazole compounds, and adducts of imidazole compounds with epoxy resins, preferably 2-ethyl-4-methylimidazolium and 1-benzyl-2-phenylimidazolium.

[0135] As an imidazole curing accelerator, commercially available products can be used, such as "P200-H50" manufactured by Mitsubishi Chemical Corporation.

[0136] Examples of guanidine curing accelerators include: dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1-methylbiguanidine, 1-ethylbiguanidine, 1-n-butylbiguanidine, 1-n-octadecylbiguanidine, 1,1-dimethylbiguanidine, 1,1-diethylbiguanidine, 1-cyclohexylbiguanidine, 1-allylbiguanidine, 1-phenylbiguanidine, 1-(o-tolyl)biguanidine, etc., with dicyandiamide and 1,5,7-triazabicyclo[4.4.0]dec-5-ene being preferred.

[0137] Examples of organometallic curing accelerators include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include: cobalt(II) acetylacetonate, cobalt(III) acetylacetonate, cobalt(II) acetylacetonate, copper(II) acetylacetonate, zinc(II) acetylacetonate, iron(III) acetylacetonate, nickel(II) acetylacetonate, and manganese(II) acetylacetonate. Examples of organometallic salts include zinc octoate, tin octoate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

[0138] When using a curing accelerator, the amount of the curing accelerator in the resin composition relative to 100% by mass of the non-volatile components is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, even 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 stated range, the dielectric constant and coefficient of linear thermal expansion of the cured resin composition can generally be reduced, or the mechanical strength of the cured product can be increased.

[0139] The resin composition contained in the resin composition layer may include inorganic fillers as needed. Inorganic fillers are typically contained in the resin composition in particulate form.

[0140] Inorganic filler materials are typically made of inorganic compounds. Examples of inorganic filler materials include: silicon dioxide, 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 phosphotungstenate. One type of inorganic filler material can be used alone, or two or more can be used in combination. Silicon dioxide is particularly preferred. Examples of silicon dioxide include amorphous silicon dioxide, fused silicon dioxide, crystalline silicon dioxide, synthetic silicon dioxide, and hollow silicon dioxide. Furthermore, spherical silicon dioxide is preferred.

[0141] Commercially available inorganic filler materials include, for example: Nippon Steel & Sumitomo Metal Materials Co., Ltd.’s “SP60-05” and “SP507-05”; YC100C, “YA050C”, “YA050C-MJE” and “YA010C”; SILFIL NSS-3N, “SILFIL NSS-4N” and “SILFIL NSS-5N”; SC2500SQ, “SO-C4”, “SO-C2” and “SO-C1”; and DENKA Corporation’s “UFP-30”, “DAW-03” and “FB-105FD”.

[0142] The average particle size of the inorganic filler material is not particularly limited, but it is preferably 0.01 μm or larger, more preferably 0.05 μm or larger, particularly preferably 0.1 μm or larger, preferably less than 10 μm, more preferably less than 5 μm, and particularly preferably less than 1 μm. The average particle size of the inorganic filler material can be determined by laser diffraction scattering based on the Mie scattering theory. Specifically, a laser diffraction scattering particle size distribution measuring device can be used to prepare the particle size distribution of the inorganic filler material on a volume basis, and the median particle size can be used as the average particle size for measurement. The sample for measurement can be prepared by weighing 100 mg of inorganic filler material and 10 g of methyl ethyl ketone into a vial and dispersing it ultrasonically for 10 minutes. For the sample, a laser diffraction particle size distribution measuring device can be used, with the light source wavelength set to blue and red, to measure the volume-based particle size distribution of the inorganic filler material in a flow cell manner. The average particle size is calculated based on the obtained particle size distribution as the median particle size. Examples of laser diffraction particle size distribution measuring devices include the "LA-960" manufactured by Horiba Manufacturing Co., Ltd.

[0143] There is no particular limitation on the specific surface area of ​​inorganic filler materials, but 0.1 m² is preferred. 2 / g or higher, preferably 0.5 m 2 / g or higher, preferably 1.0 m 2 / g or higher, preferably 50 m 2 Below / g, preferably 30 m 2 Below / g, especially 15 m 2 / g or less. The specific surface area of ​​inorganic filler materials can be obtained by using a BET fully automated specific surface area measuring device (Macsorb HM-1210 manufactured by Mountech Co., Ltd.) to adsorb nitrogen gas onto the sample surface and calculate the specific surface area using the BET multi-point method.

[0144] Inorganic fillers are preferably surface-treated with suitable surface treatment agents. Surface treatment can improve the moisture resistance and dispersibility of inorganic fillers. Examples of surface treatment agents include fluorinated silane coupling agents, aminosilane coupling agents, epoxysilane coupling agents, mercaptosilane coupling agents, silane coupling agents, alkoxysilanes, organosilazane compounds, and titanate coupling agents. A single surface treatment agent can be used, or two or more can be used in combination.

[0145] Commercially available surface treatment agents include, for example: KBM403 (3-epoxypropoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Industry Co., Ltd., KBM803 (3-mercaptopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Industry Co., Ltd., KBE903 (3-aminopropyltriethoxysilane) manufactured by Shin-Etsu Chemical Industry Co., Ltd., KBM573 (N-phenyl-3-aminopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Industry Co., Ltd., SZ-31 (hexamethyldisilazane) manufactured by Shin-Etsu Chemical Industry Co., Ltd., KBM103 (phenyltrimethoxysilane) manufactured by Shin-Etsu Chemical Industry Co., Ltd., KBM-4803 (long-chain epoxy silane coupling agent) manufactured by Shin-Etsu Chemical Industry Co., Ltd., and KBM-7103 (3,3,3-trifluoropropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Industry Co., Ltd.

[0146] From the perspective of improving the dispersibility of inorganic fillers, the degree of surface treatment by surface treatment agents should preferably be controlled within a specified range. Specifically, it is preferable that 100% by mass of the inorganic filler has been surface treated with 0.2% to 5% by mass of a surface treatment agent, more preferably with 0.2% to 3% by mass of a surface treatment agent, and particularly preferably with 0.3% to 2% by mass of a surface treatment agent.

[0147] The degree of surface treatment by surface treatment agents can be evaluated by the carbon content per unit surface area of ​​the inorganic filler. From the viewpoint of improving the dispersibility of the inorganic filler, the preferred carbon content per unit surface area of ​​the inorganic filler is 0.02 mg / m². 2 The above, preferably 0.1 mg / m 2 The above, and even better, is 0.2 mg / m². 2 That's all. On the other hand, from the viewpoint of suppressing the increase in melt viscosity of the resin composition and melt viscosity in sheet form, the carbon content per unit surface area of ​​the inorganic filler material is preferably 1.0 mg / m². 2 The following is preferable: 0.8 mg / m 2 The following is even better: 0.5 mg / m 2 the following.

[0148] The carbon content per unit surface area of ​​inorganic filler materials can be determined after cleaning the surface-treated inorganic filler material with a solvent (e.g., methyl ethyl ketone (MEK)). Specifically, sufficient MEK is added as a solvent to the surface-treated inorganic filler material, and ultrasonic cleaning is performed at 25°C for 5 minutes. After removing the supernatant and drying the solid components, the carbon content per unit surface area of ​​the inorganic filler material can be determined using a carbon analyzer. A suitable carbon analyzer is the "EMIA-320V" manufactured by Horiba Corporation.

[0149] When inorganic filler is used, the content of inorganic filler in the resin composition is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, preferably 50% by mass or more, particularly preferably 60% by mass or more, preferably 90% by mass or less, and more preferably 80% by mass or less, relative to 100% by mass of non-volatile components in the resin composition.

[0150] The resin composition contained in the resin composition layer may include any components other than those mentioned above, as needed. Examples of such arbitrary components include organometallic compounds such as organocopper compounds, organozinc compounds, and organocobalt compounds, as well as resin additives such as flame retardants, thickeners, defoamers, leveling agents, adhesion promoters, colorants, and surfactants. These components may be used individually or in combination of two or more.

[0151] There are no particular limitations on the thickness of the resin composition layer. From the viewpoint of obtaining an insulating layer with high insulating ability, the thickness of the resin composition layer is preferably 5 μm or more, more preferably 10 μm or more. Furthermore, 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.

[0152] [2.4. Manufacturing method of resin sheet]

[0153] There are no limitations on the manufacturing method of the resin sheet. The resin sheet can be manufactured by, for example, a manufacturing method that includes a step of forming a release layer on a support and a step of forming a resin composition layer on the release layer.

[0154] There are no limitations on the method for forming a release layer on the support. For example, the release layer can be formed by a method including the steps of applying a liquid composition for forming a release layer containing a release agent and a solvent onto the support, and drying the applied liquid composition.

[0155] Water, organic solvents, or a combination of both can be used as solvents in the liquid composition. Amphiphilic organic solvents are preferred. An amphiphilic organic solvent is defined as an organic solvent in which water has a solubility of 5% by mass or more at 20°C. Specific examples of amphiphilic organic solvents include alcohol solvents, ether solvents, ketone solvents, ester solvents, ethylene glycol derivative solvents, amine solvents, and lactam solvents. The concentration of the non-volatile component in the liquid composition is not particularly limited, but is preferably 2% to 30% by mass, more preferably 3% to 20% by mass. Furthermore, in addition to mold release agents and solvents, the liquid composition may further include any components such as antioxidants, UV absorbers, lubricants, and colorants.

[0156] Methods for coating a liquid composition onto a support include, for example, gravure roll coating, reverse roll coating, wirebar coating, lip coating, air knife coating, curtain flowcoating, spraying, dipping, and brushing. Among these, gravure roll coating is preferred.

[0157] After applying the liquid composition to the support, the liquid composition is dried to obtain a release layer on the support. There are no particular limitations on the drying method; for example, heating drying or vacuum drying can be used.

[0158] After drying, the film containing the support and release layer can be stretched as needed. Stretching reduces the degree of orientation crystallization on the support surface, thus increasing the adhesion between the support and the release layer. Furthermore, after drying, the film containing the support and release layer can be heat-treated. Heat treatment improves the release properties of the release layer. Especially when drying, stretching, and heat treatment are performed in-line, the release layer is subjected to high-temperature heat treatment under tension on the support, thus improving release properties while suppressing quality degradation. For example, a successive biaxial stretching method can be used, where a liquid composition is coated onto a support stretched along a uniaxial direction, the coated liquid composition is dried, and then stretched in a direction perpendicular to the aforementioned direction, followed by heat treatment.

[0159] There are no limitations on the method for forming the resin composition layer on the release layer. For example, the resin composition layer can be manufactured by a method including the steps of applying a resin varnish containing a resin composition and a solvent onto the release layer, and drying the applied resin varnish.

[0160] Organic solvents are typically used as solvents. Specific examples of solvents include: ketone solvents such as acetone, methyl ethyl ketone (MEK), and cyclohexanone; acetate solvents such as ethyl acetate, butyl acetate, acetic acid cellosolve, propylene glycol monomethyl ether acetate, and carbitol acetate; carbitol solvents such as cellosolve and butyl carbitol; aromatic solvents such as toluene and xylene; amide solvents such as dimethylformamide, dimethylacetamide (DMAc), and N-methylpyrrolidone; etc. A single solvent can be used, or two or more can be used in combination.

[0161] Methods for applying resin varnish to the release layer include, for example: gravure coating, micro-gravure coating, reverse coating, kiss reverse coating, die coating, slot die coating, lip coating, comma coating, blade coating, roller coating, knife coating, curtain coating, chamber gravure coating, slotorifice coating, spraying, and dip coating.

[0162] After applying a resin varnish to the release layer, the applied liquid composition is dried to obtain a resin composition layer on the release layer. There are no particular limitations on the drying method; methods such as heat drying or hot air drying can be used. There are no particular limitations on the drying conditions; drying is generally carried out when the content of organic solvent in the resin composition layer is typically 10% by mass or less, preferably 5% by mass or less. Depending on the boiling point of the organic solvent in the resin varnish, for example, if a resin varnish containing 30% to 60% by mass of organic solvent is used, the resin composition layer can be formed by drying at 50°C to 150°C for 3 to 10 minutes.

[0163] The method for manufacturing the resin sheet may further include, in addition to the steps of forming a release layer on a support and forming a resin composition layer on the release layer, any other steps. For example, the manufacturing method may include a step of rolling the resulting resin sheet into a roll. Furthermore, the manufacturing method may include a step of applying a protective film to the resin composition layer. The protective film helps to prevent debris from adhering to the resin composition layer and causing damage. Resin sheets with a protective film can generally be used by peeling off the protective film.

[0164] [3. Second process: Lamination of resin composition layer to substrate]

[0165] Figure 2 This is a schematic cross-sectional view illustrating the resin sheet 100 and substrate 200 in the second step of a method for manufacturing a printed wiring board according to an embodiment of the present invention. Figure 2 As shown, in one embodiment of the present invention, the method for manufacturing a printed wiring board includes a second step after the first step, in which a resin composition layer 130 of a resin sheet 100 is laminated with a substrate 200.

[0166] Examples of substrates 200 include glass epoxy boards, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates. Furthermore, substrate 200 may have a conductor layer (not shown) on one or both sides as part of it. This conductor layer may be patterned, for example, to function as a circuit. As substrate 200, an inner layer substrate for printed wiring boards can be used. Furthermore, as substrate 200, an inner layer circuit board, which has a conductor layer serving as a circuit on one or both sides, can be used. Moreover, intermediate products to be further formed with insulating and / or conductor layers during the manufacture of printed wiring boards can also be used as substrate 200. Furthermore, components can be integrated into substrate 200.

[0167] The lamination of the resin composition layer 130 to the substrate 200 is typically performed by heating and pressing the resin composition layer 130 to the substrate 200. Specific examples of the lamination method include heating and pressing the resin sheet 100 to the substrate 200 from the support 110 side, thereby bonding the resin composition layer 130 to the substrate 200. As a component for heating and pressing the resin sheet 100 to the substrate 200 (hereinafter also referred to as a "heat-pressing component," not shown), examples include heated metal plates (SUS end plates, etc.) or metal rollers (SUS rollers, etc.). Preferably, instead of directly pressing the heat-pressing component onto the resin sheet 100, it is pressed using an elastic material such as heat-resistant rubber, so that the resin composition layer 130 fully conforms to the surface irregularities of the substrate 200.

[0168] The lamination of the resin composition layer 130 to the substrate 200 can be performed, for example, by vacuum lamination. In vacuum lamination, the heating and pressing temperature is preferably in the range of 60°C to 160°C, more preferably 80°C to 140°C; the heating and pressing pressure is preferably in the range of 0.098 MPa to 1.77 MPa, more preferably 0.29 MPa to 1.47 MPa; and the heating and pressing time is preferably in the range of 20 seconds to 400 seconds, more preferably 30 seconds to 300 seconds. Lamination is preferably performed under reduced pressure conditions of 26.7 hPa or less.

[0169] After lamination, the laminated resin sheet 100 can be smoothed under normal pressure (atmospheric pressure), for example, by pressing the heated pressing component from the support 110 side. The pressing conditions for the smoothing treatment can be the same as the heating pressing conditions for the lamination described above. Lamination and smoothing treatment can be performed continuously using a vacuum laminator.

[0170] [4. Third step: Curing of the resin composition layer]

[0171] Figure 3 This is a schematic cross-sectional view of the resin sheet 100 and the substrate 200 in the third step of the manufacturing method of the printed wiring board according to one embodiment of the present invention. Figure 3 In the resin composition layer 130, the insulating layer, which serves as the cured resin composition layer, is specifically represented by the symbol "230". For example... Figure 3 As shown, in one embodiment of the present invention, the method for manufacturing a printed wiring board involves, after the second step, forming a resin composition layer 130 (see reference 130). Figure 1 and Figure 2 The third step is to cure the insulating layer 230 to obtain the insulation layer.

[0172] The resin composition layer 130 can be cured by a method corresponding to the curability of the resin composition contained in the resin composition layer 130. For example, if a thermosetting resin composition is used, the resin composition layer 130 can be cured by appropriately heating the resin composition layer 130.

[0173] The thermosetting conditions of the resin composition layer 130 will vary depending on the type of resin composition. The preferred curing temperature is 120°C to 240°C, more preferably 150°C to 220°C, and even more preferably 170°C to 200°C. The preferred curing time is 5 minutes to 120 minutes, more preferably 10 minutes to 100 minutes, and even more preferably 15 minutes to 90 minutes.

[0174] Before heat 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, before heat curing the resin composition layer 130, the resin composition layer 130 may be preheated at a temperature of 50°C or higher and lower than 120°C (preferably 60°C or higher and lower than 115°C, more preferably 70°C or higher and lower than 110°C) for 5 minutes or more (preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes, and even more preferably 15 minutes to 100 minutes).

[0175] [5. Sixth step: Hole formation]

[0176] Figure 4 This is a schematic cross-sectional view illustrating the resin sheet 100 and substrate 200 with holes 140 formed in the sixth step of a method for manufacturing a printed wiring board according to an embodiment of the present invention. Figure 4 As shown, in one embodiment of the present invention, the method for manufacturing a printed wiring board may include a sixth step, after the third step and before the fifth step, in which holes 140 are formed in the insulating layer 230, which is a cured resin composition layer.

[0177] Holes 140 are typically formed in a manner that penetrates the insulating layer 230 along the thickness direction. Furthermore, the release layer 120 is typically removed in the portion where holes 140 are formed, so holes 140 are formed not only in the insulating layer 230 but also in the release layer 120. Figure 4 The example shown illustrates an instance where the hole 140 is formed before the fourth process, thus the support 110 also has the hole 140 formed. When the hole 140 is formed before the fourth process, the formation of pits (not shown) is suppressed, and a hole 140 with a good shape is easily formed. However, the hole 140 can also be formed after the fourth process. When the hole 140 is formed after the fourth process, it is typically formed on the insulating layer 230 and the release layer 120 (the residual release layer 121 described later) located on the insulating layer 230.

[0178] The method for forming the hole 140 can be appropriate depending on the composition of the resin composition used to form the insulating layer 230. Examples of methods for forming the hole 140 include laser irradiation, etching, and mechanical drilling. The hole 140 formed in this way can be used as a through hole or via in a printed wiring board. The size and shape of the hole 140 can be appropriately determined according to the design of the printed wiring board.

[0179] As described above, when a hole 140 is formed by opening a hole in the insulating layer 230, such as Figure 4 As shown, contamination 240 may form. Typically, contamination 240 is formed in such a way that it protrudes from the inner wall of the hole 140 that opens in the insulating layer 230. This contamination 240 is removed in the fifth process described later.

[0180] [6. Fourth step: Peeling off the support]

[0181] Figure 5 This is a schematic cross-sectional view illustrating the intermediate multilayer body 300 and the peeling body 400 obtained in the fourth step of the manufacturing method of the printed wiring board according to one embodiment of the present invention. Figure 5 As shown, in one embodiment of the present invention, the method for manufacturing a printed wiring board includes a fourth step of peeling off the support 110 after the third step.

[0182] The support 110 is peeled off such that at least a portion 121 of the release layer 120 remains on the insulating layer (cured resin composition layer) 230. Therefore, by peeling off the support 110, an intermediate multilayer body 300 is obtained, which sequentially comprises a substrate 200, an insulating layer 230, and at least a portion 121 of the release layer 120 in the thickness direction. In the following description, at least a portion 121 of the release layer 120 provided in the intermediate multilayer body 300 is sometimes appropriately referred to as the "residual release layer" 121. 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 provided in the resin sheet 100, but preferably a part of the release layer 120. Unless otherwise stated, "at least a portion," "a portion," and "entire" of the release layer 120 refer to "at least a portion," "a portion," and "entire" in the thickness direction, respectively. Figure 5 The image shows an example where a portion of the release layer 120 of the resin sheet 100 remains on the insulating layer 230, forming a residual release layer 121.

[0183] In the fourth step, the support 110 is peeled off, thus obtaining a peeled body 400 containing the peeled support 110. When the peeling of the support 110 is performed such that a portion of the release layer 120 remains as a residual release layer 121 on the insulating layer 230, the peeled support 110 will have a portion 122 of the release layer 120 attached to it. In the following description, the portion 122 of the release layer 120 attached to the support 110 will sometimes be appropriately referred to as the "peeled release layer" 122. Therefore, in this case, a peeled body 400 containing the support 110 and the peeled release layer 122 can be obtained. Furthermore, when the peeling of the support 110 is performed such that the entire release layer 120 remains as a residual release layer 121 on the insulating layer 230, the peeled body 400 does not include the peeled release layer 122 attached to the support 110. Figure 5 The image shows an example of a release body 400 comprising a support 110 and a release layer 122.

[0184] There are no limitations on the method of peeling off the support 110. For example, the support 110 can be pulled (stretched), the substrate 200 can be pulled, or both the support 110 and the substrate 200 can be pulled.

[0185] Various methods exist for obtaining the intermediate multilayer body 300 by peeling off the support body 110. For example, a method using a release agent capable of cohesive failure during the peeling of the support body 110 as the material of the release layer 120 can be employed. Cohesive failure of the release agent refers to failure within the release agent itself. When using a release agent capable of cohesive failure, due to the stress applied during the peeling of the support body 110, the release layer 120 can be destroyed internally while the support body 110 is being peeled off. Thus, the release layer 120 can be divided into a residual release layer 121 remaining on the insulating layer 230 and a release release layer 122 peeled off along with the support body 110. Therefore, an intermediate multilayer body 300 including the residual release layer 121 can be obtained. Such a release agent capable of cohesive failure during the peeling of the support body 110 can be obtained by appropriately adjusting the composition of the release agent.

[0186] Another method for obtaining the intermediate multilayer 300 by peeling off the support 110 is, for example, adjusting the combination of the material of the support 110 and the material of the release layer 120 (i.e., the release agent) to a combination with low affinity. When the support 110 and the release layer 120 are formed of materials with low affinity, the support 110 and the release layer 120 can separate at the interface of the support 110 and the release layer 120 due to the stress applied during the peeling of the support 110. Thus, the entire release layer 120 may remain on the insulating layer 230, forming a residual release layer 121. Therefore, an intermediate multilayer 300 containing the residual release layer 121 can be obtained. Such a combination of the material of the support 110 and the release agent with 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 for obtaining the intermediate multilayer 300 by peeling off the support 110 is not limited to the examples described above.

[0187] At the point before the oxidation treatment in the fifth step, the intermediate multilayer 300 sequentially comprises, in the thickness direction, a substrate 200, an insulating layer 230 serving as a cured resin composition layer, a residual release layer 121, and a release surface 300U. The release surface 300U of this intermediate multilayer 300 (i.e., the surface on the side of the residual release layer 121) preferably has a specific water contact angle θ. A Specifically, the water contact angle θ of the demolding surface 300U before the fifth process. A Ideally, the angle should be above 75°; better, above 80°; especially good, above 85°; preferably below 110°; better, below 100°; especially good, below 95°. This provides a water contact angle θ of sufficient value. A For example, this can be achieved using a release agent with low polarity. The release surface 300U of the intermediate multilayer body 300 has a water contact angle θ within the aforementioned range. A In this case, the residual release layer 121 can have high resistance to oxidants. Therefore, the residual release layer 121 can effectively protect the insulation layer 230 from oxidants, thus effectively reducing the surface roughness of the insulation layer 230 after the fifth process.

[0188] The water contact angle of the surface can be measured at 25°C using the circular method (true circular method) with a water contact angle measuring instrument (manufactured by Kyowa Interface Science Co., Ltd., DropMaster "DMs-401").

[0189] The water contact angle θ of the demolding surface before the fifth process is 300U. A Surface 130U of the release layer 120 side of the resin composition layer 130 before curing (refer to) Figure 2 Water contact angle θ B The absolute value of the difference | θA -θ B | It is better to be within a specific range. Specifically, the absolute value |θ A -θ B | Ideally, the angle should be 8° or higher; even better, 10° or higher; and exceptionally good, 13° or higher. There is no upper limit; for example, it can be below 35°.

[0190] In most cases, the resin composition before curing and the release agent have different water affinities. This difference in water affinity can be attributed to the water contact angle θ of the release surface (300°) on the residual release layer surface. A The water contact angle θ between the surface 130U of the resin composition layer 130 before curing and the surface 130U. B The difference is reflected in the water contact angle θ. Furthermore, the water affinity of the resin composition layer 130 before curing can be related to the water affinity of the cured insulating layer. Therefore, as described above, the water contact angle θ... A Angle of contact with water θ B The difference can be represented by the difference in properties between the residual release layer 121 and the insulating layer 230.

[0191] The water contact angle of the surface 130U of the resin composition layer 130 before curing can be measured, for example, by the following method: After the second process and before the resin composition layer 130 is cured, the support 110 and the release layer 120 are peeled off. By peeling, the surface 130U of the resin composition layer 130 is exposed, so the water contact angle of the surface 130U can be measured.

[0192] If a water contact angle θ of 300U demolding surface is used A It can be confirmed that a residual release layer 121 exists on the insulating layer 230. Generally, a difference in water contact angle occurs between the surface to which the release agent is attached and the surface to which it is not. Therefore, the release surface 300U has a water contact angle θ with the surface 130U of the resin composition layer 130 to which the release agent is not attached. B There are differences in water contact angle θ A In this case, it can be known that the release surface 300U is coated with release agent, so it can be known that there is a residual release layer 121 on the insulating layer 230. Specifically, the absolute value |θ A -θ B | When the temperature is typically above 8°, preferably above 10°, and especially preferably above 13°, it can be determined that there is a residual release layer 121 on the insulating layer 230.

[0193] Furthermore, if the water contact angle is used, it can be confirmed that the release body 400 includes a release layer 122. The water contact angle θ of the release layer side surface 400D of the release body 400 obtained in the fourth process is... CThis will vary depending on whether or not a release layer 122 is peeled off. Here, the surface 400D on the release layer side of the release body 400 refers to the surface exposed by peeling off the support body 110, and thus represents the surface in contact with the residual release layer 121 before peeling off the support body 110. Sometimes, the surface 400D of the release body 400 is appropriately referred to as the "peeling surface" 400D of the release body 400.

[0194] When the release body 400 includes the release layer 122, the release body 400 sequentially comprises a support 110, the release layer 122, and a release surface 400D in the thickness direction. Therefore, in this case, the release surface 400D can correspond to the surface of the release layer 122. In this case, the release surface 400D can have a water contact angle θ with the release surface 300U of the intermediate multilayer body 300, which corresponds to the surface of the layer containing the same release agent. A Equal water contact angle θ C Therefore, it can be determined that the water contact angle θ of the release surface 300U of the intermediate multilayer body 300 is... A The water contact angle θ between the peel surface 400D of the peel body 400 and the peel body 400 C The absolute value of the difference | θ A -θ C In smaller cases, the release body 400 includes a release layer 122. Specifically, the absolute value |θ A -θ C | When the angle is typically below 17°, preferably below 15°, more preferably below 10°, and especially preferably below 6°, it can be determined that the release body 400 contains the release layer 122.

[0195] On the other hand, when the release body 400 does not contain the release layer 122, the release body 400 sequentially includes a support body 110 and a release surface 400D in the thickness direction. Therefore, in this case, the release surface 400D does not correspond to the surface of the release layer 122. Thus, the release surface 400D may have a water contact angle θ with the release surface 300U of the intermediate multilayer body 300. A Significantly different water contact angles θ C Therefore, it can be determined that the water contact angle θ of the release surface 300U of the intermediate multilayer body 300 is... A The water contact angle θ between the peel surface 400D of the peel body 400 and the peel body 400 C The absolute value of the difference | θ A -θ C In cases where the value is large, the release body 400 does not contain the release layer 122. Specifically, the absolute value |θ A -θ C | If the situation is outside the range mentioned above, it can be determined that the peeling body 400 does not contain the peeling release layer 122.

[0196] After the second process and before the resin composition layer 130 is cured, the support 110 and the release layer 120 are peeled off to obtain a release film (not shown) having the support 110 and the release layer 120. The water contact angle θ of the surface of the release layer 120 side of this release film is shown. D It can also be confirmed that the peeling body 400 includes the peeling and demolding layer 122.

[0197] 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 may have a water contact angle θ with the surface of the release film on the side of the release layer 120 that corresponds to the surface of the release film containing the same release agent. D Equal water contact angle θ C Therefore, it can be determined that the water contact angle θ of the release surface 400U of the release body 400 is... C The water contact angle θ between the surface of the peel layer 120 side of the peeling film and the surface of the peeling film. D The absolute value of the difference | θ C -θ D In smaller cases, the release body 400 includes a release layer 122. Specifically, the absolute value |θ C -θ D | When the angle is usually below 13°, preferably below 10°, and especially preferably below 8°, it can be determined that the peeling body 400 contains the peeling and demolding layer 122.

[0198] On the other hand, when the peeling body 400 does not contain the peeling release layer 122, as described above, the peeling surface 400D corresponding to the surface of the peeling release layer 122 may have a water contact angle θ with the surface of the release film on the side of the release layer 120. D Significantly different water contact angles θ C Therefore, it can be determined that the water contact angle θ of the release surface 400D of the release body 400 is... C The water contact angle θ between the surface of the peel layer 120 side of the peeling film and the surface of the peeling film. D The absolute value of the difference | θ C -θ D In cases where the value is large, the release body 400 does not contain the release layer 122. Specifically, the absolute value |θ C -θ D | If the situation is outside the range mentioned above, it can be determined that the peeling body 400 does not contain the peeling release layer 122.

[0199] The presence of a release layer, residual release layer, or peeled release layer on a particular surface can also be confirmed by observation using a scanning electron microscope (SEM). Surfaces with release layers, residual release layers, or peeled release layers differ in surface shape from surfaces without these layers. Therefore, the presence of release layers, residual release layers, and peeled release layers can be confirmed by observing the surface shape using SEM.

[0200] [7. Fifth step: Oxidation treatment]

[0201] Figure 6 This is a schematic cross-sectional view of the printed wiring board 500 obtained by oxidizing the intermediate multilayer body 300 in the fifth step of the manufacturing method of the printed wiring board 500 according to one embodiment of the present invention. In the manufacturing method of the printed wiring board according to one embodiment of the present invention, a fifth step is performed after the fourth step. In this fifth step, an oxidation treatment is performed to bring an oxidant into contact with the release surface 300U of the intermediate multilayer body 300, thereby obtaining... Figure 6 The printed wiring board 500 is shown. In this oxidation process, when the insulating layer 230 has holes 140 formed, the oxidant is usually brought into overall contact with the release surface 300U, including the portion where the holes 140 are formed.

[0202] In the fifth step of the manufacturing method described in this embodiment, both improved contamination removal and reduced surface roughness of the insulating layer can be achieved. The inventors speculate that the principle underlying this effect is as follows. However, the scope of the present invention is not limited to the principles described below.

[0203] In the fifth process, if the oxidant comes into contact with the release surface 300U of the intermediate multilayer body 300, the oxidant enters the hole 140 at the location where the hole 140 is formed. The oxidant entering the hole 140 oxidizes and removes the contaminant 240. No residual release layer 121 is provided in the release surface 300U of the intermediate multilayer body 300 at the location where the hole 140 is formed. Therefore, the oxidant smoothly penetrates the hole 140, effectively removing the contaminant 240.

[0204] On the other hand, in the release surface 300U of the intermediate multilayer body 300, at the location where the hole 140 is not formed, a residual release layer 121 is provided on the insulating layer 230. Thus, the insulating layer 230 is protected by the residual release layer 121, preventing the oxidant from easily entering the insulating layer 230. Specifically, the oxidant typically enters the insulating layer 230 after removing the residual release layer 121 through oxidation. If the oxidant enters the insulating layer 230, the surface 230U of the insulating layer 230 becomes roughened. However, because the residual release layer 121 delays the oxidation process of the insulating layer 230, the roughening process of the surface 230U of the insulating layer 230 is suppressed. Therefore, a low roughness of the surface 230U of the insulating layer 230 obtained after oxidation treatment can be achieved. Sometimes, the surface 230U of the oxidized insulating layer 230 is appropriately referred to as the "roughened surface" 230U. In addition, the residual release layer 121 is usually removed by oxidation based on an oxidant, so the resulting printed wiring board 500 does not contain the residual release layer 121.

[0205] There are no particular limitations on the oxidizing agent; examples include alkaline permanganate solutions obtained by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. The concentration of permanganate in the alkaline permanganate solution is preferably 5% to 10% by mass. Commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact P," "Concentrate Compact CP," and "Dosing solution Securiganth P" manufactured by ATOTECH JAPAN Co., Ltd. One oxidizing agent may be used alone, or two or more may be used in combination.

[0206] There are no particular limitations on the method of contacting the oxidant with the release surface 300U. For example, the intermediate multilayer body 300 can be immersed in the oxidant, allowing the oxidant to contact the release surface 300U. Furthermore, the processing conditions for contacting the oxidant with the release surface 300U are preferably set appropriately to remove the contaminant 240. For example, oxidation treatment using an oxidant such as an alkaline permanganate solution is preferably performed by contacting the release surface 300U with the oxidant heated to 60°C to 80°C for 10 to 30 minutes.

[0207] For the fifth step, it is preferable to include a swelling treatment that brings the swelling liquid into contact with the release surface 300U of the intermediate multilayer body 300 before the oxidation treatment. The swelling liquid is not particularly limited, and examples include alkaline solutions and surfactant solutions. Alkaline solutions are preferred, and sodium hydroxide and potassium hydroxide solutions are more preferred. Commercially available swelling liquids include, for example, "Swelling Dip Securiganth P" and "Swelling Dip Securiganth SBU" manufactured by Ammet Japan Co., Ltd. One type of swelling liquid may be used alone, or two or more may be used in combination.

[0208] There are no particular limitations on the swelling treatment using a swelling liquid. For example, the intermediate multilayer 300 can be immersed in the swelling liquid, allowing the swelling liquid to contact the demolding surface 300U. From the viewpoint of suppressing the swelling of the insulating layer 230 to an appropriate level, the temperature of the swelling liquid is preferably 30°C to 90°C, and more preferably 40°C to 80°C. Furthermore, from the viewpoint of suppressing the swelling of the insulating layer 230 to an appropriate level, the contact time between the swelling liquid and the demolding surface 300U is preferably 1 minute to 20 minutes, and more preferably 5 minutes to 15 minutes.

[0209] For the fifth step, it is preferable to include a neutralization treatment, following the oxidation treatment, involving contacting the neutralizing solution with the roughened surface 230U of the insulating layer 230 of the resulting printed wiring board 500. The neutralizing solution is preferably an acidic aqueous solution. Examples of commercially available neutralizing solutions include "Reduction solution Securiganth P" manufactured by Ammet Japan Co., Ltd. One type of neutralizing solution may be used alone, or two or more may be used in combination.

[0210] There are no particular limitations on the neutralization treatment using a neutralizing solution. For example, the printed wiring board 500 can be immersed in the neutralizing solution, allowing the neutralizing solution to contact the roughened surface 230U. From an operational point of view, the temperature of the neutralizing solution is preferably 30°C to 80°C, more preferably 40°C to 70°C. Furthermore, from an operational point of view, the contact time between the neutralizing solution and the roughened surface 230U is preferably 5 minutes to 30 minutes, more preferably 5 minutes to 20 minutes.

[0211] If a fifth process is used, a printed wiring board 500 having a substrate 200, an insulating layer 230, and a roughened surface 230U sequentially in the thickness direction can be obtained. Therefore, in this 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, even more preferably 200 nm or less, and particularly preferably 150 nm or less. There is no particular limitation on the lower limit; it is preferably 20 nm or more, and more preferably 30 nm or more.

[0212] The arithmetic mean roughness Ra of the roughened surface 230U of the printed wiring board 500 can be measured as follows: at the location where the hole 140 is not formed, a non-contact surface roughness meter (Veeco Instruments "WYKONT3300") is used, in VSI mode with a 50x lens, and the measurement range is set to 121μm × 92μm.

[0213] When the insulating layer 230 has a hole 140, if a fifth process is used, the contaminant 240 inside the hole 140 can be removed. This can, for example, reduce the maximum contaminant length from the bottom wall of the hole 140 to less than 5 μm. The maximum contaminant length can be measured by observing the area around the bottom of the hole 140 using a scanning electron microscope (SEM). Furthermore, the bottom wall of the hole 140 refers to the portion of the hole 140 that is close to the substrate 200.

[0214] [8. Seventh step: Formation of the conductor layer]

[0215] Figure 7 This is a schematic cross-sectional view of the printed wiring board 500 in the seventh step of the manufacturing method of the printed wiring board 500 according to the first embodiment of the present invention, in which the conductor layer 250 is formed. Figure 7 As shown, in one embodiment of the present invention, the manufacturing method of the printed wiring board 500 may include a seventh step of forming a conductor layer 250 after the fifth step. In the seventh step, the conductor layer 250 is typically formed on the roughened surface 230U of the insulating layer 230, thereby obtaining a printed wiring board 500 having a substrate 200, an insulating layer 230, and a conductor layer 250 sequentially in the thickness direction.

[0216] The conductor material used for conductor layer 250 is not particularly limited. In a preferred embodiment, conductor layer 250 comprises one or more metals selected from gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. Conductor layer 250 can be a single metal layer or an alloy layer. Examples of alloy layers include layers formed from alloys of two or more metals selected from the above-mentioned metals (e.g., nickel-chromium alloy, copper-nickel alloy, and copper-titanium alloy). From the viewpoint of versatility, cost, and ease of pattern formation in forming conductor layer 250, a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper is preferred; or an alloy layer of nickel-chromium alloy, copper-nickel alloy, or copper-titanium alloy. A single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper is more preferred; or an alloy layer of nickel-chromium alloy, and a single metal layer of copper is even more preferred.

[0217] The conductor layer 250 can be a single-layer structure or a multi-layer structure comprising two or more single-metal layers or alloy layers made of different types of metals or alloys. When the conductor layer 250 is 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 nickel-chromium alloy.

[0218] The thickness of the conductor layer 250 varies depending on the desired design of the printed wiring board 500, but is generally 3μm to 35μm, preferably 5μm to 30μm.

[0219] The conductor layer 250 is formed by plating. For example, the conductor layer 250 with the desired wiring pattern can be formed by plating on the roughened surface 230U of the insulating layer 230 using techniques such as semi-additive or fully additive methods. From the viewpoint of ease of manufacturing, it is preferable to form it by the semi-additive method.

[0220] The following describes an example of forming the conductor layer 250 using a semi-additive method. First, a 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 seed layer, exposing a portion of the seed layer, corresponding to the desired wiring pattern. After forming a metal layer on the exposed seed layer by electrolytic plating, the mask pattern is removed. Then, the unwanted seed layer is removed by etching or the like, thereby forming the conductor layer 250 having the desired wiring pattern.

[0221] In the manufacturing method described in 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 made finer.

[0222] Furthermore, when the insulating layer 230 has a hole 140, a conductor layer 250 is usually also formed within the hole 140. Since the contaminant 240 is effectively removed, the formation of defects in the conductor layer 250 formed within the hole 140 can be suppressed.

[0223] [9. Variations]

[0224] The method for manufacturing printed wiring boards described in the above embodiments can be further modified. For example, a multilayer printed wiring board can be manufactured by repeatedly forming insulating and conductor layers based on the above processes as needed. Furthermore, processes other than the first to seventh processes described above can also be performed.

[0225] [10. Applications of the manufactured printed wiring boards]

[0226] The printed wiring board manufactured by the above-described manufacturing method is applicable to a wide range of semiconductor devices. Examples of semiconductor devices equipped with printed wiring boards include various semiconductor devices used in electrical products (such as computers, mobile phones, digital cameras, and televisions) and transportation vehicles (such as motorcycles, automobiles, trams, ships, and aircraft).

[0227] Semiconductor devices can be manufactured, for example, by mounting components (semiconductor chips) on conductive locations within a printed circuit board. A "conductive location" refers to a location on the printed circuit board where electrical signals are conducted; this location can be on the surface or embedded, either way. Furthermore, semiconductor chips can utilize any electrical circuit elements made of semiconductor materials.

[0228] The method of mounting semiconductor chips during the manufacture of semiconductor devices is not particularly limited as long as the semiconductor chip functions effectively. Examples of mounting methods include wire bonding mounting, flip chip mounting, mounting with a solderless built-in layer (BBUL), mounting with anisotropic conductive film (ACF), and mounting with non-conductive film (NCF). Here, "mounting with a solderless built-in layer (BBUL)" refers to "a mounting method in which the semiconductor chip is directly embedded in a recess of a printed circuit board, thereby connecting the semiconductor chip to the wiring on the printed circuit board." Example

[0229] The present invention will be specifically described below with reference to embodiments. However, the present invention is not limited to the embodiments described below. In the following description, unless otherwise stated, "parts" and "%" refer to "parts by mass" and "% by mass," respectively. Furthermore, unless otherwise stated, the operations described below are performed under normal temperature and pressure conditions.

[0230] [Evaluation Method]

[0231] The thickness of the layer was measured at 25°C using a curve fitting method with an Optical Nano Gauge C12562 manufactured by Hamamatsu Photonics Co., Ltd. Measurements were taken at 10 points, and the average value of the 10 points was used as the measured value.

[0232] (Method for measuring water contact angle)

[0233] The water contact angle of the surface was measured at 25°C using a true circle method with a water contact angle measuring instrument (Kyowa Interface Science Co., Ltd., DropMaster "DMs-401"). Measurements were taken at 5 points, and the average value of the 5 points was obtained as the measured value.

[0234] (Determination of the arithmetic mean roughness (Ra value) of the insulating layer surface)

[0235] The arithmetic mean roughness (Ra value) of the insulating layer surface was obtained using a non-contact surface roughness meter (WYKO NT3300, manufactured by Veeco Instruments Co., Ltd.), in VSI mode with a 50x lens, and with the measurement range set to 121μm × 92μm. Measurements were taken at 10 points, and the average value of the 10 points was calculated as the measured value.

[0236] [Manufacturing Example 1. Manufacturing of Release Film 1]

[0237] <Manufacturing of Acid-Modified Polypropylene Resin (A-1)>

[0238] 280 g of propylene-ethylene copolymer (propylene / ethylene = 99 / 1 (mass ratio)) was melted in a four-necked flask under a nitrogen atmosphere. Then, the temperature was maintained at 170°C, and 32.0 g of maleic anhydride (as an unsaturated carboxylic acid) and 6.0 g of dicumyl peroxide (as a free radical generator) were added over 1 hour with stirring. The reaction was then allowed to proceed for 1 hour. After the reaction was complete, the resulting product was added to a large amount of acetone to precipitate the resin. The resin was then washed several times with acetone to remove unreacted maleic anhydride. The resin was then dried under reduced pressure in a vacuum dryer to obtain acid-modified polyolefin resin (A-1).

[0239] <Preparation of Aqueous Dispersions of Acid-Modified Polypropylene Resin (A-1)>

[0240] Prepare a stirrer with a heater and a 1-liter pressure-resistant, sealable glass container. Add 60.0 g of acid-modified polyolefin resin (A-1), 45.0 g of ethylene glycol n-butyl ether (boiling point 171°C), 6.9 g of N,N-dimethylethanolamine (boiling point 134°C, 1.0 equivalent to the carboxyl group of the maleic anhydride unit in the resin), and 188.1 g of distilled water to the glass container of the stirrer. Stir at 300 rpm. No resin sedimentation was observed at the bottom of the container during stirring, confirming that the resin was in suspension. Maintaining this state, the heater was turned on after 10 minutes. The system temperature was then maintained at 140°C, and stirring was continued for 60 minutes. Finally, air cooling was used, maintaining stirring at 300 rpm while cooling to room temperature (approximately 25°C). The contents of the glass container were pressure filtered (0.2 MPa air pressure) through a 300-mesh stainless steel filter (0.035 mm wire diameter, plain weave) to obtain a homogeneous aqueous dispersion of acid-modified polyolefin resin (A-1) (25% by mass concentration of non-volatile components). Almost no resin residue remained on the filtered filter.

[0241] <Preparation of Liquid Composition 1 for Forming Release Layer>

[0242] An aqueous dispersion of acid-modified polyolefin resin (A-1) with 100 parts by mass (based on non-volatile components), an aqueous solution of polyvinyl alcohol ("JT-05" manufactured by VAM & POVAL Co., Ltd., Japan, with a saponification rate of 94.5%, a degree of polymerization of 500, and a non-volatile component concentration of 8% by mass) with 300 parts by mass (based on non-volatile components), and an aqueous solution of an oxazoline-containing compound (EPOCROS "WS-700" manufactured by Nippon Shokubai Co., Ltd., with a non-volatile component concentration of 25% by mass) used as a crosslinking agent with 7 parts by mass (based on non-volatile components) were mixed, and water was added to adjust the final non-volatile component concentration to 6.0% by mass to obtain a liquid composition 1 for forming a release layer.

[0243] <Manufacturing of Release Film 1>

[0244] A resin composition comprising amorphous silica particles with 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) was prepared. The amount of amorphous silica particles in the resin composition was 0.08% by mass. The resin composition was melt-extruded at 280 °C and rapidly cooled by electrostatic pinning using a T-die method to obtain an unstretched film with a thickness of 600 μm. Next, the unstretched film was stretched 3.5 times using a longitudinal stretching roller heated to 90 °C to obtain a longitudinally stretched film.

[0245] Using a reverse gravure coating machine, the liquid composition 1 for forming the release layer is applied at a concentration of 5 g / m². 2 A coating amount of (WET conversion) is applied to one side of the longitudinally stretched film. Then, using a transverse stretching tenter, the longitudinally stretched film is stretched 4.5 times at 120°C, heat-treated at 230°C for 10 seconds, cooled, and wound up to obtain a release film 1 comprising a support film and a release layer. The resulting release film 1 has a thickness of 38 μm, and the release layer has a thickness of approximately 0.08 μm.

[0246] [Manufacturing Example 2. Manufacturing of Release Film 2]

[0247] <Preparation of Liquid Composition 2 for Forming Release Layer>

[0248] The polyvinyl alcohol aqueous solution (manufactured by VAM & POVAL Co., Ltd. of Japan, "JL-05E", with a saponification rate of 82.0%, a degree of polymerization of 500, and a non-volatile component concentration of 8% by mass) was used instead of the polyvinyl alcohol aqueous solution (manufactured by VAM & POVAL Co., Ltd. of Japan, "JT-05"), which was based on 500 parts by mass of non-volatile components. Otherwise, the liquid composition 2 for forming the release layer was manufactured by the same method as the process of "manufacturing of liquid composition 1 for forming release layer" in manufacturing example 1.

[0249] <Manufacturing of Release Film 2>

[0250] The release film 2, which is used to form the release layer, is obtained by replacing the liquid composition 1 for forming the release layer with the liquid composition 2 for forming the release layer, except that the release film 2 having the support film and the release layer is obtained by the same method as the process "manufacturing of release film 1" in manufacturing example 1.

[0251] [Example 1]

[0252] (1-1. Manufacturing of Resin Sheets)

[0253] While stirring, 6 parts of bisphenol-type epoxy resin (Nippon Steel & Sumitomo Chemical Co., Ltd. "ZX1059", epoxy equivalent approximately 169, a 1:1 mixture of bisphenol A and bisphenol F), 9 parts of bixylenol-type epoxy resin (Mitsubishi Chemical Co., Ltd. "YX4000HK", epoxy equivalent approximately 185), 21 parts of biphenyl-type epoxy resin (Nippon Kayaku Co., Ltd. "NC3000L", epoxy equivalent 288), and 10 parts of phenoxy resin (Mitsubishi Chemical Co., Ltd. "YX7553BH30", a 1:1 solution of cyclohexanone and methyl ethyl ketone (MEK) with 30% by mass of non-volatile components) were heated and dissolved in a mixed solvent of 20 parts of naphtha and 5 parts of cyclohexanone to obtain a mixture. After cooling to room temperature, 6 parts of a triazine-based cresol varnish curing agent (hydroxyl equivalent 151, DIC Corporation "LA-3018-50P", 50% non-volatile component 2-methoxypropanol solution), 20 parts of an active ester curing agent (DIC Corporation "HPC-8000-65T", weight average molecular weight approximately 2700, active group equivalent approximately 223, 65% non-volatile component toluene solution), 2 parts of an amine curing accelerator (4-dimethylaminopyridine (DMAP), 5% non-volatile component MEK solution), 2 parts of a flame retardant (Sanko Corporation "HCA-HQ", 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide, average particle size 2 μm), and 170 parts of inorganic filler were mixed into the mixture and uniformly dispersed using a high-speed rotary mixer. The mixture was then filtered using a cartridge filter (ROKITECHNO, SHP050) to produce resin varnish A. As the inorganic filler material, spherical silica (Yaduma, SOC2, average particle size 0.5 μm, specific surface area 5.8 m²) surface-treated with an aminosilane coupling agent (Shin-Etsu Chemical, KBM573) was used. 2 / g).

[0254] The resin varnish A was uniformly applied to the surface of the release layer side of the release film 1 obtained in Manufacturing Example 1 using a die coater, and dried at 80°C to 120°C (average 100°C) for 6 minutes to obtain a resin sheet 1 having a support film, a release layer, and a resin composition layer in sequence. The thickness of the resin composition layer of the resin sheet 1 is 40 μm.

[0255] (1-2. Lamination of the resin composition layer to the inner circuit board)

[0256] A glass cloth substrate epoxy resin double-sided copper-clad laminate (copper foil thickness 18μm, substrate thickness 0.8 mm, Panasonic Electric Works Co., Ltd. "R1515A") was immersed on both sides in MAG Co., Ltd. "CZ8100" to roughen the copper surface. As a result, an inner layer circuit board was obtained.

[0257] A batch vacuum pressure laminator (Nichigo-Morton Corporation, two-stage stacking laminator "CVP700") is used to laminate resin sheets 1 onto both sides of the inner layer circuit board. This lamination is performed by bonding the resin composition layer of the resin sheet 1 to the inner layer circuit board. Furthermore, the lamination is performed by reducing the pressure to below 13 hPa for 30 seconds, followed by pressing at 100°C, 0.74 MPa, and for 30 seconds.

[0258] (1-3. Curing of the resin composition layer)

[0259] After laminating the resin composition layer with the inner circuit board, the resin composition layer was thermally cured at 130°C for 30 minutes and then at 170°C for 30 minutes with a support film attached, forming an insulating layer. This yielded an evaluation sample containing a support film, a release layer, an insulating layer, and an inner circuit board in sequence. The thickness of the insulating layer on the inner circuit was 40 μm.

[0260] (1-4. Peeling of the support membrane)

[0261] The evaluation sample was cooled to room temperature (approximately 25°C), and the support membrane was peeled off to obtain the intermediate multilayer and the peeled-off body.

[0262] (1-5. Oxidation treatment of the insulating layer)

[0263] The intermediate multilayer was immersed in a swelling solution (SwellingDip Securiganth P containing diethylene glycol monobutyl ether, Ametek Japan Co., Ltd.) at 60°C for 10 minutes, followed by immersion in a roughening solution (Concentrate Compact P (an aqueous solution of KMnO4: 60 g / L and NaOH: 40 g / L, Ametek Japan Co., Ltd.)) as an oxidizing agent at 80°C for 20 minutes, and then immersed in a neutralization solution (Reduction solution Securiganth P, Ametek Japan Co., Ltd.) at 40°C for 5 minutes to obtain a printed wiring board. The printed wiring board was dried at 80°C for 30 minutes.

[0264] (1-6. Evaluation)

[0265] After steps (1-2) and before step (1-3), the release film is partially peeled off. The surface of the release film in contact with the resin composition layer (i.e., the surface of the release film on the release layer side) is observed using SEM, confirming the presence of a release layer on this surface. Furthermore, the water contact angle θ1 of this surface is measured using the method described above. Next, the surface of the resin composition layer exposed after the release film is peeled off (i.e., the surface of the resin composition layer on the release layer side before curing) is observed using SEM, confirming the absence of a release layer on this surface. Furthermore, the water contact angle θ2 of this surface is measured using the method described above.

[0266] After steps (1-4) and before step (1-5), the surface of the insulating layer exposed after the support film is peeled off (i.e., the release surface of the intermediate multilayer) was observed using SEM, confirming the presence of a release layer on this surface. Furthermore, the water contact angle θ3 of this surface was measured using the method described above. Next, the surface of the peeled body in contact with the insulating layer (i.e., the peel surface of the peeled body) was observed using SEM, confirming the presence of a release layer on this surface. Furthermore, the water contact angle θ4 of this surface was measured using the method described above.

[0267] After the aforementioned steps (1-5), the arithmetic mean roughness (Ra value) of the roughened surface (the surface subjected to oxidation treatment) of the insulating layer of the printed wiring board was measured using the method described above.

[0268] (1-7. Formation and evaluation of through holes)

[0269] The surface of the support film side of the evaluation sample obtained in steps (1-3) was irradiated with a laser. For laser irradiation, a CO2 laser processing machine (LK-2K212 / 2C) manufactured by Via Machinery Co., Ltd. was used, with a frequency of 2000 Hz, a pulse width of 3 microseconds, an output power of 0.95 W, and a shot count of 3. This formed through-holes penetrating the support film, release layer, and insulating layer. The top diameter (aperture diameter) of the through-hole on the surface of the insulating layer was 50 μm, and the diameter of the through-hole on the bottom surface of the insulating layer was 40 μm. The top diameter refers to the diameter of the opening of the through-hole. Then, the support film was peeled off to obtain an intermediate multilayer body having an inner circuit board, an insulating layer, and a residual release layer. The obtained intermediate multilayer body was immersed in a swelling solution, a roughening solution, and a neutralizing solution under the same conditions as in steps (1-5) to remove contaminants from the bottom of the through-holes. The contaminant removal performance was evaluated according to the following criteria.

[0270] <Evaluation of stain removal performance>

[0271] The area around the bottom of the through-hole was observed using a scanning electron microscope (SEM). The maximum contamination length from the bottom wall of the through-hole was determined based on the obtained images. Based on this maximum contamination length, contamination removeability was evaluated according to the following criteria;

[0272] "Good": Maximum contamination length less than 5μm;

[0273] “Defective”: The maximum length of contamination is 5μm or more.

[0274] [Example 2]

[0275] The release film 2 obtained in Manufacturing Example 2 was used instead of the release film 1 obtained in Manufacturing Example 1. Otherwise, the printed wiring board was manufactured, the water contact angles θ1 to θ4 were measured, and the arithmetic mean roughness (Ra value) was measured using the same method as in Example 1. Furthermore, SEM observation confirmed the presence of a release layer on the surfaces where water contact angles θ1, θ3, and θ4 were measured, while no release layer was found on the surface where the water contact angle θ2 was measured.

[0276] [Example 3]

[0277] The curing conditions in the process of heat-curing the resin composition layer were changed to 100°C for 30 minutes, and then to 170°C for 30 minutes. Otherwise, the printed wiring board was manufactured, the water contact angles θ1 to θ4 were measured, and the arithmetic mean roughness (Ra value) was measured using the same method as in Example 1. Furthermore, SEM observation confirmed the presence of a release layer on the surfaces where water contact angles θ1, θ3, and θ4 were measured, while no release layer was found on the surface where the water contact angle θ2 was measured.

[0278] [Example 4]

[0279] The curing conditions in the process of heat-curing the resin composition layer were changed to 170°C for 30 minutes. Otherwise, the printed wiring board was manufactured, the water contact angles θ1 to θ4 were measured, and the arithmetic mean roughness (Ra value) was measured using the same method as in Example 1. Furthermore, SEM observation confirmed the presence of a release layer on the surfaces where water contact angles θ1, θ3, and θ4 were measured, while no release layer was found on the surface where the water contact angle θ2 was measured.

[0280] [Example 5]

[0281] While stirring, 30 parts of biphenyl-type epoxy resin (epoxy equivalent approximately 290, manufactured by Nippon Kayaku Co., Ltd., "NC3000H"), 5 parts of naphthalene-type tetrafunctional epoxy resin (epoxy equivalent 162, manufactured by DIC Co., Ltd., "HP-4700"), 15 parts of liquid bisphenol A-type epoxy resin (epoxy equivalent 180, manufactured by Mitsubishi Chemical Co., Ltd., "jER828EL") and 2 parts of phenoxy resin (weight average molecular weight 35000, manufactured by Mitsubishi Chemical Co., Ltd., "YX7553BH30", methyl ethyl ketone (MEK) solution with 30% by mass of non-volatile components) were heated and dissolved in a mixed solvent of 8 parts MEK and 8 parts cyclohexanone to obtain a mixture. To this mixture, 32 parts of a triazine-based phenolic varnish curing agent (phenolic hydroxyl equivalent of approximately 124, manufactured by DIC Corporation, "LA-7054", a MEK solution with 60% by mass of non-volatile components), 0.2 parts of a phosphorus-based curing accelerator (manufactured by Hokko Chemical Industry Co., Ltd., "TBP-DA", tetrabutylphosphonic decanoate), 160 parts of inorganic filler, and 2 parts of a polyvinyl butyral resin solution (weight average molecular weight 27,000, glass transition temperature 105°C, manufactured by Sekisui Chemical Industry Co., Ltd., "KS-1", a mixed solution of ethanol and toluene with 15% by mass of non-volatile components in a 1:1 mass ratio) were uniformly dispersed using a high-speed rotary mixer to prepare resin varnish B. As the inorganic filler material, spherical silica (SOC2, manufactured by Yaduma Co., Ltd., with an average particle size of 0.5 μm and a specific surface area of ​​5.8 m²) surface-treated with an aminosilane coupling agent ("KBM573" manufactured by Shin-Etsu Chemical Co., Ltd.) was used. 2 / g). When the total mass of non-volatile components in resin varnish B is set at 100% by mass, the content of inorganic filler (spherical silica) is 69.5% by mass.

[0282] Resin varnish B was used instead of resin varnish A prepared in Example 1. Furthermore, release film 2 obtained in Manufacturing Example 2 was used instead of release film 1 obtained in Manufacturing Example 1. Furthermore, the curing conditions in the process of heat-curing the resin composition layer were changed to curing conditions of 100°C for 30 minutes, and then at 170°C for 30 minutes. Apart from the above, the manufacturing of the printed wiring board, the measurement of water contact angles θ1 to θ4, and the measurement of arithmetic mean roughness (Ra value) were performed using the same method as in Example 1. Furthermore, by observation using SEM, it was confirmed that a release layer existed on the surfaces where water contact angles θ1, θ3, and θ4 were measured, but no release layer was found on the surface where water contact angle θ2 was measured.

[0283] [Example 6]

[0284] The pressing conditions in the process of laminating resin sheets 1 on both sides of the inner circuit board will be changed to 100°C and 1 kgf / cm² pressure. 2(0.098 MPa), 30 seconds. In addition, the printed wiring board was manufactured, the water contact angles θ1 to θ4 were measured, and the arithmetic mean roughness (Ra value) was measured using the same method as in Example 1. Furthermore, by observation using SEM, it was confirmed that a release layer existed on the surfaces where the water contact angles θ1, θ3, and θ4 were measured, but no release layer was found on the surface where the water contact angle θ2 was measured.

[0285] [Example 7]

[0286] The pressing conditions in the process of laminating resin sheets 1 on both sides of the inner circuit board will be changed to 80°C and 1 kgf / cm. 2 (0.098 MPa), 30 seconds. In addition, the printed wiring board was manufactured, the water contact angles θ1 to θ4 were measured, and the arithmetic mean roughness (Ra value) was measured using the same method as in Example 1. Furthermore, by observation using SEM, it was confirmed that a release layer existed on the surfaces where the water contact angles θ1, θ3, and θ4 were measured, but no release layer was found on the surface where the water contact angle θ2 was measured.

[0287] [Comparative Example 1]

[0288] No heat curing process was performed on the resin composition layer. Otherwise, the printed wiring board was manufactured, water contact angles θ1 to θ4 were measured, and the arithmetic mean roughness (Ra value) was measured using the same method as in Example 1. In Comparative Example 1, no heat curing of the resin composition layer was performed, so the water contact angle θ3 represents the water contact angle of the surface of the uncured resin composition layer exposed after the support film was peeled off (corresponding to the release surface). Furthermore, the water contact angle θ4 represents the water contact angle of the surface of the peeled-off body (corresponding to the peel surface) on the side of the peeled-off body that is in contact with the resin composition layer when the support film was peeled off without curing the resin composition layer. Furthermore, observation using SEM confirmed the presence of a release layer on the surfaces where water contact angles θ1 and θ4 were measured, but not on the surfaces where water contact angles θ2 and θ3 were measured. Moreover, in Comparative Example 1, the resin composition layer was damaged due to oxidation treatment, and the arithmetic mean roughness (Ra value) could not be measured.

[0289] [Comparative Example 2]

[0290] Release film 3 (AL-5 manufactured by Lintec Corporation, a multilayer film comprising a polyethylene terephthalate film as a support film and an alkyd release layer) was used instead of release film 1 obtained in Manufacturing Example 1. Otherwise, the manufacturing of the printed wiring board, the measurement of water contact angles θ1 to θ4, and the measurement of arithmetic mean roughness (Ra value) were performed using the same method as in Example 1. Furthermore, observation using SEM confirmed the presence of a release layer on the surfaces where water contact angles θ1 and θ4 were measured, while no release layer was found on the surfaces where water contact angles θ2 and θ3 were measured.

[0291] [result]

[0292] The results of the above-described embodiments and comparative examples are shown in the following table. In the table below, the abbreviations have the following meanings:

[0293] θ1: The water contact angle of the surface of the release film on the release layer side, which is peeled off before the resin composition layer cures. This θ1 corresponds to the water contact angle θ. D ;

[0294] θ2: The water contact angle of the surface of the resin composition layer exposed after the release film is peeled off before the resin composition layer cures. This θ2 is equivalent to the water contact angle θ. B ;

[0295] θ3: The water contact angle of the surface of the insulating layer exposed after the support film is peeled off following the curing of the resin composition layer. This θ3 corresponds to the water contact angle θ. A ;

[0296] θ4: The water contact angle of the surface of the peeled-off support, which is in contact with the insulating layer, after the resin composition layer has cured. This θ4 corresponds to the water contact angle θ. C ;

[0297] Ra: Arithmetic mean roughness of the roughened surface of the insulating layer after oxidation treatment.

[0298] [Table 1]

[0299] .

[0300] Explanation of symbols

[0301] 100 Resin Sheets

[0302] 110 Support body

[0303] 120 release layer

[0304] 121 Residual release layer

[0305] 122 Peel off the release layer

[0306] 130 Resin Composition Layer

[0307] Surface of the release layer side of the 130U resin composition layer before curing

[0308] 140 holes

[0309] 200 substrates

[0310] 230 Insulating layer (cured resin composition layer)

[0311] Roughened surface of 230U insulation layer

[0312] 240 Contamination

[0313] 250 conductor layer

[0314] 300 intermediate multilayer body

[0315] 300U intermediate multi-layer body demolding surface

[0316] 400 peel body

[0317] The peeling surface of the 400D peel body

[0318] 500 Printed Wiring Board.

Claims

1. A method for manufacturing a printed wiring board, the method comprising, in sequence, the following first to fifth steps: In the first step, a resin sheet is prepared, which sequentially comprises a support, a release layer, and a resin composition layer. In the second process, the resin composition layer is laminated to the substrate; In the third step, the resin composition layer is cured; In the fourth step, the support body is peeled off to obtain an intermediate multilayer body, which sequentially comprises at least a portion of the substrate, the resin composition layer, and the release layer; In the fifth step, the oxidant is brought into contact with the surface of the release layer side of the intermediate multilayer body. A sixth step, which is included after the third step and before the fifth step, involves forming pores in the resin composition layer. The fifth step includes: removing the release layer of the intermediate multilayer body using the oxidant that is in contact with the surface of the release layer side of the intermediate multilayer body, and roughening the resin composition layer.

2. The method for manufacturing a printed wiring board according to claim 1, wherein, A portion of the release layer is attached to the support body that has been peeled off in the fourth process.

3. The method for manufacturing a printed wiring board according to claim 1, wherein, The fourth step includes: destroying the demolding layer inside the demolding layer.

4. The method for manufacturing a printed wiring board according to claim 1, wherein, The water contact angle of the surface of the release layer side of the intermediate multilayer body is greater than 75° and less than 110°.

5. The method for manufacturing a printed wiring board according to claim 1, wherein, The water contact angle of the surface of the release layer side of the intermediate multilayer body is 85° or higher.

6. The method for manufacturing a printed wiring board according to claim 1, wherein, The water contact angle of the surface of the release layer side of the intermediate multilayer body is less than 95°.

7. The method for manufacturing a printed wiring board according to claim 1, wherein, The absolute value of the difference between the water contact angle of the surface of the release layer side of the intermediate multilayer body and the water contact angle of the surface of the release layer side of the peeled body containing the support body peeled off in the fourth process is less than 17°.

8. The method for manufacturing a printed wiring board according to claim 1, wherein, The absolute value of the difference between the water contact angle of the surface of the release layer side of the intermediate multilayer body and the water contact angle of the surface of the release layer side of the peeled body containing the support body peeled off in the fourth process is less than 15°.

9. The method for manufacturing a printed wiring board according to claim 1, wherein, The fifth step is followed by a seventh step, which involves forming a conductor layer.

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