Method for manufacturing substrate, and resin sheet

Abstract

Provided is a method for manufacturing a substrate, the method making it possible to uniformly protect a substrate end part, and being capable of yielding a substrate end part having exceptional resistance to roughening treatment and yielding a substrate having exceptional crack resistance. This method for manufacturing a substrate comprises: (A) a step for preparing a core substrate provided with a first main surface, a second main surface, and an end surface sandwiched between the first main surface and the second main surface; (B) a step for preparing a resin sheet provided with a support and a resin composition layer provided on the support; and (C) a step for covering the end surface provided to the core substrate with the resin composition layer provided to the resin sheet.

Description

Substrate manufacturing method and resin sheet

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

[0002] Circuit boards, such as printed wiring boards, are widely used in various electronic devices. A known manufacturing method for circuit boards and other substrates involves a build-up method in which insulating layers and conductive layers are alternately stacked on a core substrate. The insulating layer is formed, for example, by forming a resin composition layer containing a resin composition and then curing the resin composition layer. A method for forming a resin composition layer on a substrate includes, for example, using a resin sheet comprising a support and a resin composition layer provided on the support. More specifically, a method is known in which a resin sheet is laminated onto a substrate such that the resin composition layer on the resin sheet is in contact with the main surface of the substrate (see Patent Document 1).

[0003] When forming an insulating layer using the resin composition layer of a resin sheet, if the resin sheet is laminated onto a substrate, a portion of the resin composition layer may fluidize and seep out to the outside of the substrate. From the viewpoint of suppressing such seepage, the resin composition layer was sometimes omitted around the edges of the main surface of the substrate.

[0004] As mentioned above, since a resin composition layer was not always provided around the edges of the substrate, a varnish-like resin composition was sometimes applied to the edge surface (and its peripheral edge) of the substrate, and the edges of the substrate were protected by curing the applied resin composition (see Patent Documents 2-4).

[0005] Japanese Unexamined Patent Publication No. 2022-172221, Japanese Unexamined Patent Publication No. 2015-193820, Japanese Unexamined Patent Publication No. 2005-262653, Japanese Patent No. 5735047

[0006] However, the inventors have found that in a method of applying a varnish-like resin composition to the edge surface of a substrate, the resin composition flows before curing, making it impossible to uniformly protect the edge of the substrate with the cured resin composition. Furthermore, in a method of manufacturing a substrate, an insulating layer may be formed on the main surface of the substrate after protecting the edge of the substrate, and this insulating layer may be subjected to a roughening treatment. In such a case, the edge of the substrate may also be subjected to the roughening treatment of the insulating layer, but the inventors have found that in a method of applying a varnish-like resin composition to the edge surface of a substrate, the cured resin composition provided at the edge of the substrate cannot withstand the roughening treatment, and some or all of the cured resin may detach from the substrate.

[0007] Furthermore, when substrates are stored in storage containers such as racks, physical impacts may be applied to the edges of the substrates. However, the inventors have found that the aforementioned method of applying a varnish-like resin composition to the edge of the substrate is insufficient to mitigate physical impacts to the edges of the substrate, resulting in cracks such as chips and breaks in the substrate. In recent years, glass substrates have been used as substrate materials due to their superior mechanical properties and manufacturing costs. However, cracks are particularly noticeable when using glass substrates, so there is a need for a method to manufacture substrates with excellent crack resistance.

[0008] The present invention has been made in view of the above, and aims to provide a method for manufacturing a substrate that can uniformly protect the edges of the substrate, provide substrate edges with excellent resistance to roughening treatment, and provide a substrate with excellent crack resistance; and a resin sheet that can be used to carry out the method for manufacturing the substrate.

[0009] The inventors diligently studied to solve the above problems. As a result, the inventors found that the above problems can be solved by a method for manufacturing a substrate, which includes the steps of: (A) preparing a core substrate having a first main surface, a second main surface, and an end surface sandwiched between the first and second main surfaces; (B) preparing a resin sheet having a support and a resin composition layer provided on the support; and (C) covering the end surface of the core substrate with the resin composition layer of the resin sheet. Based on this, the inventors completed the present invention. That is, the present invention includes the following.

[0010] <1> A method for manufacturing a substrate, comprising: (A) preparing a core substrate having a first main surface, a second main surface, and an end surface sandwiched between the first main surface and the second main surface; (B) preparing a resin sheet having a support and a resin composition layer provided on the support; and (C) covering the end surface of the core substrate with the resin composition layer provided on the resin sheet. <2> The method for manufacturing a substrate according to <1>, further comprising: (D) curing the resin composition layer after step (C); <3> The method for manufacturing a substrate according to <2>, further comprising: applying a roughening treatment to the cured resin composition layer after step (D); <4> The method for manufacturing a substrate according to <3>, further comprising: removing the support provided on the resin sheet after step (C) and before applying a roughening treatment to the cured resin composition layer. <5> The manufacturing method according to any one of <2> to <4>, further comprising the step of forming a conductive layer on a cured resin composition layer after step (D). <6> The manufacturing method according to any one of <1> to <5>, wherein step (C) is performed by a hot roll lamination method. <7> The manufacturing method according to any one of <1> to <6>, wherein the resin composition layer of the resin sheet contains a thermosetting resin. <8> The manufacturing method according to <7>, wherein the thermosetting resin contains an epoxy resin. <9> The manufacturing method according to any one of <1> to <8>, wherein the resin composition layer of the resin sheet contains an organic solvent, and the content of the organic solvent is 0.6% by mass or more and 10% by mass or less, when the total components of the resin composition layer are considered as 100% by mass. <10> The manufacturing method according to any one of <1> to <9>, wherein the melt viscosity of the resin composition layer of the resin sheet at a temperature of 100°C is 500 poise or more and 10,000 poise or less. <11> The manufacturing method according to any one of <1> to <10>, wherein the thickness of the resin composition layer of the resin sheet is 5 μm or more. <12> The manufacturing method according to any one of <1> to <11>, wherein the length of the short axis of the resin composition layer of the resin sheet is 30 mm or less. <13> The manufacturing method according to any one of <1> to <12>, wherein in step (A), the core substrate is a glass substrate.<14> The manufacturing method according to any one of <1> to <13>, wherein in step (A), the core substrate further comprises an insulating layer on at least one of the first main surface and the second main surface. <15> The manufacturing method according to any one of <1> to <13>, wherein in step (A), the core substrate does not comprise an insulating layer on the first main surface and the second main surface. <16> The manufacturing method according to <15>, wherein step (C) comprises, in this order, a step of joining a part of the resin composition layer of the resin sheet to either the first main surface and the second main surface of the core substrate, and a step of covering the end surface of the core substrate with the remaining part of the resin composition layer of the resin sheet by folding the resin sheet from the support side. <17> The manufacturing method according to <15> or <16>, further comprising, after step (C), a step of forming an insulating layer on at least one of the first main surface and the second main surface of the core substrate. <18> A semiconductor device comprising a substrate manufactured by the manufacturing method described in any one of <1> to <17>. <19> A resin sheet comprising a support and a resin composition layer provided on the support; a resin sheet for use in a method of manufacturing a substrate, comprising the steps of: preparing a core substrate having a first main surface, a second main surface, and an end surface sandwiched between the first main surface and the second main surface; and covering the end surface of the core substrate with the resin composition layer provided in the resin sheet. <20> The resin sheet according to <19>, wherein the resin composition layer provided in the resin sheet comprises a thermosetting resin. <21> The resin sheet according to <19> or <20>, wherein the melt viscosity of the resin composition layer provided in the resin sheet at a temperature of 100°C is 500 poise or more and 10,000 poise or less. <22> The resin sheet according to any one of <19> to <21>, wherein the length of the short axis of the resin composition layer provided in the resin sheet is 30 mm or less.

[0011] The present invention provides a method for manufacturing a substrate that can uniformly protect the edges of the substrate, resulting in substrate edges with excellent resistance to roughening treatment, and a substrate with excellent crack resistance; and a resin sheet that can be used to carry out the said substrate manufacturing method.

[0012] Hereinafter, the present invention will be described in detail with reference to embodiments and examples. However, the present invention is not limited to the following embodiments and examples, and can be implemented with any modifications without departing from the scope of the claims of the present invention and the scope of equivalents thereof.

[0013] [Description of Terms] The embodiments described in the present specification may be used in combination with each other regardless of expressions such as "preferred" or "more preferred". For example, for the description of a numerical range, a range combining the upper and lower limits of each range and the numerical values of the examples may be used.

[0014] In the present specification, the "non-volatile component" referred to for a resin composition refers to components other than the organic solvent described later among the components constituting the resin composition. In addition, the "resin component" referred to for a resin composition refers to components other than the inorganic filler described later among the non-volatile components constituting the resin composition.

[0015] In the present specification, the term "aromatic ring" means a ring that complies with Hückel's rule, in which the number of electrons contained in the π-electron system on the ring is 4p+2 (p is an integer of 1 or more), and includes monocyclic aromatic rings and condensed aromatic rings formed by condensation of two or more monocyclic aromatic rings. Unless otherwise specified, a monocyclic aromatic ring is preferable as the aromatic ring. The aromatic ring may be an aromatic carbocyclic ring having only carbon atoms as ring-constituting atoms, or an aromatic heterocyclic ring having heteroatoms such as an oxygen atom, a nitrogen atom, and a sulfur atom in addition to carbon atoms as ring-constituting atoms. Unless otherwise specified, the number of carbon atoms in the aromatic ring is preferably 3 or more, more preferably 4 or more or 5 or more, still more preferably 6 or more, and the upper limit thereof is preferably 24 or less, more preferably 18 or less or 14 or less, still more preferably 10 or less.

[0016] Before describing the method for producing a substrate of the present invention in detail, the resin composition contained in the resin composition layer in step (B) of the method for producing a substrate of the present invention will be described. Hereinafter, the resin composition contained in the resin composition layer may be simply referred to as "resin composition".

[0017] [Resin Composition] The resin composition is a composition containing a curable resin. The curable resin may be selected from the group consisting of thermosetting resins and photocurable resins. Therefore, as the curable resin, only a thermosetting resin may be used, only a photocurable resin may be used, or a combination of a thermosetting resin and a photocurable resin may be used.

[0018] The resin composition may further optionally contain an inorganic filler, a thermoplastic resin, a curing accelerator, an organic solvent, and other additives. Hereinafter, each component contained in the resin composition will be described in detail.

[0019] <Curable Resin> As described above, the resin composition contains a curable resin. One type of curable resin may be used alone, or two or more types may be used in combination.

[0020] As described above, the curable resin may be selected from the group consisting of thermosetting resins and photocurable resins. Among these, from the viewpoint of excellent chemical resistance, the curable resin preferably contains a thermosetting resin.

[0021] As the thermosetting resin, a resin curable when heat is applied may be used. Examples of thermosetting resins include epoxy resins, phenol resins, active ester resins, cyanate ester resins, carbodiimide resins, acid anhydride resins, amine resins, benzoxazine resins, thiol resins, and radically polymerizable resins. One type of thermosetting resin may be used alone, or two or more types may be used in combination.

[0022] When the resin composition contains a thermosetting resin as the curable resin, the content of the thermosetting resin in the resin composition, based on 100% by mass of non-volatile components in the resin composition, is preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably 25% by mass or more or 30% by mass or more, and preferably 60% by mass or less, more preferably 50% by mass or less, still more preferably 45% by mass or less, from the viewpoint of remarkably obtaining the desired effect of the present invention.

[0023] When the resin composition contains a thermosetting resin as a curable resin, the content of the thermosetting resin in the resin composition is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more or 95% by mass or more, when the total resin components in the resin composition are considered as 100% by mass. The upper limit of the content of the thermosetting resin relative to 100% by mass of the resin components in the resin composition may be 100% by mass or less (for example, 99% by mass or less, 98% by mass or less, 97% by mass or less, 96% by mass or less, 95% by mass or less, etc.).

[0024] In one preferred embodiment, the thermosetting resin includes an epoxy resin. The epoxy resin may be used alone or in combination of two or more types. The method for manufacturing a substrate in which the thermosetting resin includes an epoxy resin is preferable because it allows the end face of the core substrate to be covered with a resin composition layer having a uniform thickness, and provides a substrate edge that is particularly resistant to roughening treatment (especially roughening treatment by a wet method).

[0025] As the epoxy resin, a curable resin having epoxy groups can be used. Examples of epoxy resins include bixylenol-type epoxy resin, bisphenol A-type epoxy resin, bisphenol C-type epoxy resin, bisphenol F-type epoxy resin, bisphenol S-type epoxy resin, bisphenol AF-type epoxy resin, dicyclopentadiene-type epoxy resin, trisphenol-type epoxy resin, naphthol novolac-type epoxy resin, phenol novolac-type epoxy resin, tert-butyl-catechol-type epoxy resin, naphthalene-type epoxy resin, naphthol-type epoxy resin, anthracene-type epoxy resin, and glycidylamine-type epoxy resin. Examples include glycidyl ester type epoxy resins, cresol novolac type epoxy resins, phenol aralkyl type epoxy resins, biphenyl type epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiroring-containing epoxy resins, cyclohexane type epoxy resins, cyclohexanedimethanol type epoxy resins, naphthylene ether type epoxy resins, trimethylol type epoxy resins, tetraphenylethane type epoxy resins, isocyanurate type epoxy resins, and phenolphthaleimidine type epoxy resins.

[0026] From the viewpoint of obtaining a cured product with excellent heat resistance, it is preferable that the epoxy resin contains an aromatic skeleton. Here, an aromatic skeleton refers to a skeleton containing a chemical structure generally defined as an aromatic ring. The aromatic ring is as described above. Examples of epoxy resins containing an aromatic skeleton include bisphenol A type epoxy resin, bisphenol C type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol novolac type epoxy resin, phenol novolac type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, bisquilenol type epoxy resin, and glycidylamine type epoxy resin containing an aromatic skeleton. Examples include xy resins, glycidyl ester type epoxy resins containing aromatic skeletons, cresol novolac type epoxy resins, biphenyl type epoxy resins, linear aliphatic epoxy resins containing aromatic skeletons, epoxy resins having a butadiene structure containing aromatic skeletons, alicyclic epoxy resins containing aromatic skeletons, heterocyclic epoxy resins, spiro ring-containing epoxy resins containing aromatic skeletons, cyclohexanedimethanol type epoxy resins containing aromatic skeletons, naphthylene ether type epoxy resins, trimethylol type epoxy resins containing aromatic skeletons, and tetraphenylethane type epoxy resins containing aromatic skeletons.

[0027] The epoxy resin preferably contains an epoxy resin that contains two or more epoxy groups per molecule. The proportion of epoxy resin containing two or more epoxy groups per molecule, relative to 100% by mass of epoxy resin, is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and is usually 100% by mass or less.

[0028] 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, only solid epoxy resin, or a combination of liquid epoxy resin and solid epoxy resin. In particular, it is preferable for the epoxy resin to contain solid epoxy resin, and more preferable for it to contain a combination of liquid epoxy resin and solid epoxy resin.

[0029] As the liquid epoxy resin, a liquid epoxy resin containing two or more epoxy groups per molecule is preferred.

[0030] The liquid epoxy resin preferably contains one or more selected from the group consisting of bisphenol A type epoxy resin, bisphenol C type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, phenol novolac type epoxy resin, alicyclic epoxy resins such as alicyclic epoxy resins containing an ester skeleton, cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, and epoxy resins containing a butadiene structure.

[0031] Specific examples of liquid epoxy resins include DIC's "HP-4032," "HP-4032-D," and "HP-4032-SS" (naphthalene-type epoxy resin); Mitsubishi Chemical's "828US," "828," "828EL," and "825" (bisphenol A-type epoxy resin); Mitsubishi Chemical's "807" and "1750" (bisphenol F-type epoxy resin); Mitsubishi Chemical's "152" (phenol novolac-type epoxy resin); Mitsubishi Chemical's "630," "630LSD," and "604" (glycidylamine-type epoxy resin); DIC's "N-730A" and Nippon Steel Chemical & Material's "ZX-1059" (bisphenol Examples include: a mixture of type A epoxy resin and bisphenol F type epoxy resin; DIC Corporation's "EXA-7250" (triphenylmethane type epoxy resin); Nagase ChemteX Corporation's "EX-721" (glycidyl ester type epoxy resin); Daicel Corporation's "Celoxide 2021P" (alicyclic epoxy resin with an ester skeleton); Daicel Corporation's "PB-3600" (epoxy resin with a butadiene structure); Nippon Steel Chemical & Material Corporation's "ZX-1658" and "ZX-1658GS" (liquid 1,4-glycidylcyclohexane type epoxy resin); and Resonaq Corporation's "Showfree PETG" (pentaerythritol type epoxy resin). Liquid epoxy resins may be used individually or in combination of two or more types.

[0032] As for the solid epoxy resin, a solid epoxy resin containing two or more epoxy groups per molecule is preferred, a solid epoxy resin containing three or more epoxy groups per molecule is more preferred, and a solid epoxy resin containing three or more epoxy groups and an aromatic ring per molecule is even more preferred.

[0033] The solid epoxy resin preferably contains one or more selected from the group consisting of bixylenol-type epoxy resin, naphthalene-type epoxy resin, naphthalene-type tetrafunctional epoxy resin, cresol novolac-type epoxy resin, dicyclopentadiene-type epoxy resin, trisphenol-type epoxy resin, naphthol-type epoxy resin, biphenyl-type epoxy resin, naphthylene ether-type epoxy resin, anthracene-type epoxy resin, bisphenol A-type epoxy resin, bisphenol AF-type epoxy resin, and tetraphenylethane-type epoxy resin, and more preferably contains biphenyl-type epoxy resin.

[0034] Specific examples of solid epoxy resins include DIC's "HP4032H" (naphthalene-type epoxy resin); DIC's "HP-4700" and "HP-4710" (naphthalene-type tetrafunctional epoxy resins); DIC's "N-690" (cresol novolac-type epoxy resin); DIC's "N-695" (cresol novolac-type epoxy resin); DIC's "HP-7200", "HP-7200HH", and "HP-7200H" (dicyclopentadiene-type epoxy resin). ); "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000", "HP6000L" (naphthylene ether type epoxy resin) manufactured by DIC Corporation; "EPPN-502H" (trisphenol type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC7000L" (naphthol novolac type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC3000H", "NC3000", "NC3000L", "NC310 0 (biphenyl-type epoxy resin); "ESN475V" (naphthalene-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ESN485" (naphthol novolac-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YL6121" (biphenyl-type epoxy resin), "YX4000", "YX4000H", "YX4000HK" (bixylenol-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX8800" (anthracene-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; Osaka Gas Examples include "PG-100" and "CG-500" from Schemical Co., Ltd., "YL7760" (bisphenol AF type epoxy resin) from Mitsubishi Chemical Corporation, "YL7800" (fluorene type epoxy resin) from Mitsubishi Chemical Corporation, "1010" (solid bisphenol A type epoxy resin) from Mitsubishi Chemical Corporation, "1031S" (tetraphenylethane type epoxy resin) from Mitsubishi Chemical Corporation, and "WHR-991S" (phenolphthalein-imidine type epoxy resin) from Nippon Kayaku Co., Ltd. Solid epoxy resins may be used individually or in combination of two or more types.

[0035] When using a combination of liquid epoxy resin and solid epoxy resin as the epoxy resin, their mass ratio (liquid epoxy resin:solid epoxy resin) is preferably 1:0.1 to 1:20, more preferably 1:0.15 to 1:15, and even more preferably 1:0.2 to 1:10.

[0036] The epoxy equivalent of the epoxy resin is preferably 50 g / eq. or more, more preferably 80 g / eq. or more, even more preferably 110 g / eq. or more, preferably 5,000 g / eq. or less, more preferably 3,000 g / eq. or less, even more preferably 2,000 g / eq. or less, and even more preferably 1,000 g / eq. or less. When the epoxy equivalent of the epoxy resin is within the above range, the crosslinking density of the cured resin composition can result in a cured product with sufficient crosslinking density. The epoxy equivalent is the mass of epoxy resin containing one equivalent of epoxy groups. This epoxy equivalent can be measured according to JIS K7236.

[0037] The weight-average molecular weight (Mw) of the epoxy resin is preferably 100 or more, more preferably 150 or more, even more preferably 200 or more, preferably 5,000 or less, more preferably 3,000 or less, and even more preferably 1,500 or less. The weight-average molecular weight of the epoxy resin is the weight-average molecular weight in terms of polystyrene, measured by gel permeation chromatography (GPC).

[0038] When the resin composition contains epoxy resin, the epoxy resin content in the resin composition is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, 7% by mass or more, or 9% by mass or more, and preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, when the nonvolatile components in the resin composition are considered to be 100% by mass.

[0039] When the resin composition contains epoxy resin, the epoxy resin content in the resin composition is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 25% by mass or more or 27% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 35% by mass or less, 33% by mass or less or 31% by mass or less, when the total resin component in the resin composition is considered to be 100% by mass.

[0040] In one preferred embodiment, the thermosetting resin comprises an epoxy resin and a resin that reacts with the epoxy resin to cure the curable resin composition. The resin that reacts with the epoxy resin to cure the curable resin composition may hereinafter be referred to as the "curing agent." Examples of curing agents include phenolic resins, activated ester resins, cyanate ester resins, carbodiimide resins, acid anhydride resins, amine resins, benzoxazine resins, and thiol resins. Among these, it is preferable that the curing agent includes a thermosetting resin selected from the group consisting of phenolic resins and activated ester resins. The curing agent may be used alone or in combination of two or more types.

[0041] As the phenolic resin, a resin having one or more, preferably two or more, hydroxyl groups (phenolic hydroxyl groups) bonded to aromatic rings such as benzene rings and naphthalene rings per molecule can be used. When combined with an epoxy resin, the phenolic resin can react with the epoxy resin to cure the resin composition. From the viewpoint of heat resistance and water resistance, a phenolic resin having a novolac structure is preferred. Furthermore, from the viewpoint of adhesion, a nitrogen-containing phenolic resin is preferred, and a triazine skeleton-containing phenolic resin is more preferred. Among these, a triazine skeleton-containing phenol novolac resin is preferred from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion. The phenolic resin may be used alone or in combination of two or more types.

[0042] Specific examples of phenolic resins include "MEH-7700", "MEH-7810", "MEH-7851", and "MEH-8000H" from Meiwa Kasei Co., Ltd.; "NHN", "CBN", and "GPH" from Nippon Kayaku Co., Ltd.; and "SN-170", "SN-180", "SN-190", "SN-475", "SN-485", "SN-495", "SN-495V", and "SN-3" from Nippon Steel Chemical & Material Co., Ltd. Examples include "75", "SN-395"; "TD-2090", "TD-2090-60M", "LA-7052", "LA-7054", "LA-1356", "LA-3018", "LA-3018-50P", "LA-1356", "TD2090", "TD-2090-60M"; and "GDP-6115L", "GDP-6115H", and "ELPC75" from Gun-ei Chemical Co., Ltd.

[0043] When the resin composition contains a phenolic resin, the content of the phenolic resin in the resin composition is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, or 2% by mass or less, when the nonvolatile components in the resin composition are considered to be 100% by mass.

[0044] When the resin composition contains a phenolic resin, the content of the phenolic resin in the resin composition is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 3% by mass or more, preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, when the total resin component in the resin composition is considered to be 100% by mass.

[0045] As the active ester resin, compounds having two or more highly reactive ester groups in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds, are generally preferred. When combined with an epoxy resin, the active ester resin can react with the epoxy resin to cure the resin composition. The active ester resin is preferably obtained by a condensation reaction between a carboxylic acid compound and / or a thiocarboxylic acid compound and a hydroxy compound and / or a thiol compound. The active ester resin is preferably obtained from a carboxylic acid compound and a hydroxy compound, and more preferably from a carboxylic acid compound and a phenol compound and / or a naphthol compound. Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of phenol compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadiene-type diphenol compounds, phenol novolac, etc. Here, "dicyclopentadiene-type diphenol compound" refers to a diphenol compound obtained by condensing one molecule of dicyclopentadiene with two molecules of phenol. The active ester resin may be used alone or in combination of two or more types.

[0046] Specifically, the active ester resin is preferably at least one selected from the group consisting of dicyclopentadiene-type active ester resins, naphthalene-type active ester resins containing a naphthalene structure, active ester resins containing an acetylated phenol novolac, and active ester resins containing a benzoylated phenol novolac, and more preferably at least one selected from the group consisting of dicyclopentadiene-type active ester resins and naphthalene-type active ester resins. As the dicyclopentadiene-type active ester resin, an active ester resin containing a dicyclopentadiene-type diphenol structure is preferred.

[0047] Examples of commercially available activated ester resins include, for example, activated ester resins containing a dicyclopentadiene-type diphenol structure such as "EXB9451", "EXB9460", "EXB9460S", "EXB-8000L", "EXB-8000L-65M", "EXB-8000L-65TM", "HPC-8000L-65TM", "HPC-8000L-65T", "HPC-8000", "HPC-8000-65T", and "EXB-8000H" (manufactured by DIC Corporation); and activated ester resins containing a naphthalene structure such as "EXB-8100L-65T", "EXB-8150-60T", and "EXB-8150 Examples include: -62T, EXB-9416-70BK, HPC-8150-62T, EXB-8 (manufactured by DIC Corporation); as a phosphorus-containing active ester resin, EXB9401 (manufactured by DIC Corporation); as an active ester resin that is an acetylated phenol novolac, DC808 (manufactured by Mitsubishi Chemical Corporation); as an active ester resin that is a benzoylated phenol novolac, YLH1026, YLH1030, YLH1048 (manufactured by Mitsubishi Chemical Corporation); and as an active ester resin containing a styryl group and a naphthalene structure, PC1300-02-65MA (manufactured by Air Water Corporation).

[0048] When the resin composition contains an active ester resin, the content of the active ester resin in the resin composition is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, even more preferably 15% by mass or more, even more preferably 20% by mass or more, preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, when the nonvolatile components in the resin composition are considered to be 100% by mass.

[0049] When the resin composition contains an active ester resin, the content of the active ester resin in the resin composition is preferably 10% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more, even more preferably 50% by mass or more, and even more preferably 60% by mass or more or 63% by mass or more, when the total resin component in the resin composition is considered as 100% by mass, and preferably 80% by mass or less, more preferably 75% by mass or less, even more preferably 70% by mass or less, 68% by mass or less or 66% by mass or less.

[0050] The active group equivalent of the curing agent is preferably 50 g / eq. or more, more preferably 100 g / eq. or more, preferably 3,000 g / eq. or less, more preferably 1,000 g / eq. or less, even more preferably 500 g / eq. or less, and even more preferably 300 g / eq. or less. The active group equivalent is the mass of the curing agent per equivalent of active groups. The active group of the curing agent refers to a group that can react with the epoxy group of the epoxy resin, and varies depending on the type of curing agent. For example, the active group of phenolic resin is a phenolic hydroxyl group. For example, the active group equivalent of phenolic resin refers to the phenolic hydroxyl group equivalent, and represents the mass of the resin per equivalent of phenolic hydroxyl groups.

[0051] The weight-average molecular weight (Mw) of the curing agent is preferably 100 or more, more preferably 250 or more, even more preferably 400 or more, preferably 5,000 or less, more preferably 3,000 or less, and even more preferably 1,500 or less. The weight-average molecular weight of the curing agent is the weight-average molecular weight in terms of polystyrene, measured by gel permeation chromatography (GPC).

[0052] 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 0.01 or more, more preferably 0.05 or more, even more preferably 0.1 or more, preferably 10 or less, more preferably 5 or less, and even more preferably 3 or less, from the viewpoint of significantly obtaining the desired effects of the present invention. "Number of epoxy groups in the epoxy resin" refers to the sum of all values ​​obtained by dividing the mass of epoxy resin in the resin composition by the epoxy equivalent. Similarly, "number of active groups in the curing agent" refers to the sum of all values ​​obtained by dividing the mass of curing agent in the resin composition by the active group equivalent.

[0053] If the resin composition contains a curing agent, the content of the curing agent in the resin composition is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 35% by mass or less, 33% by mass or less, or 31% by mass or less, when the nonvolatile components in the resin composition are considered to be 100% by mass.

[0054] If the resin composition contains a curing agent, the content of the curing agent in the resin composition is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, even more preferably 60% by mass or more or 65% by mass or more, and preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less, when the resin component in the resin composition is considered to be 100% by mass, from the viewpoint of significantly obtaining the desired effects of the present invention.

[0055] <Inorganic Fillers> The resin composition may contain an inorganic filler as an optional component. The inorganic filler may be included in the resin composition in granular form and may be included in the cured product while maintaining its granular form. One type of inorganic filler may be used alone, or two or more types may be used in combination.

[0056] Inorganic compounds can be used as materials for inorganic fillers. Examples of inorganic filler materials include silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, silica and alumina are preferred, with silica being more preferred. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. Spherical silica is also preferred.

[0057] Examples of commercially available inorganic fillers include "SP60-05" and "SP507-05" from Nippon Steel Chemical & Material Co., Ltd.; "YC100C", "YA050C", "YA050C-MJE", "YA010C", "SC2500SQ", "SO-C4", "SO-C2", and "SO-C1" from Admatex Co., Ltd.; "UFP-30", "DAW-03", and "FB-105FD" from Denka Co., Ltd.; "Silfil NSS-3N", "Silfil NSS-4N", and "Silfil NSS-5N" from Tokuyama Corporation; "Cellspheres" and "MGH-005" from Taiheiyo Cement Corporation; and "Highpresica FH" from Ube Eximo Co., Ltd.

[0058] The average particle diameter of the inorganic filler is not particularly limited, but is preferably 1 μm or less, more preferably 0.7 μm or less, and still more preferably 0.5 μm or less. The lower limit of the average particle diameter is not particularly limited, but is preferably 0.01 μm or more, more preferably 0.03 μm or more, and still more preferably 0.05 μm or more. The average particle diameter of the inorganic filler can be measured by a laser diffraction / scattering method based on the Mie scattering theory. Specifically, the measurement can be carried out by preparing a volume-based particle size distribution of the inorganic filler using a laser diffraction scattering particle size distribution analyzer, and taking the median diameter of the distribution as the average particle diameter. For the measurement sample, 100 mg of the inorganic filler and 10 g of methyl ethyl ketone can be weighed into a vial and dispersed with ultrasonic waves for 10 minutes for use. Using a laser diffraction particle size distribution analyzer, the volume-based particle size distribution of the inorganic filler was measured by the flow cell method with blue and red light source wavelengths, and the average particle diameter was calculated as the median diameter from the obtained particle size distribution. Examples of the laser diffraction particle size distribution analyzer include "LA-960" manufactured by Horiba, Ltd.

[0059] The specific surface area of the inorganic filler is not particularly limited, but is preferably 0.1 m ２ / g or more, more preferably 0.5 m ２ / g or more, still more preferably 1 m ２ / g or more, 3 m ２ / g or more, or 5 m ２ / g or more. The upper limit of the specific surface area is not particularly limited, but is preferably 100 m ２ / g or less, more preferably 80 m ２ / g or less, still more preferably 60 m ２ / g or less, 50 m ２ / g or less, or 40 m ２ / g or less. The specific surface area of the inorganic filler can be obtained according to the BET method by allowing nitrogen gas to adsorb onto the surface of a sample using a specific surface area measuring apparatus ("Macsorb HM-1210" manufactured by Mountec Co., Ltd.) and calculating the specific surface area using the BET multipoint method.

[0060] It is preferable that the inorganic filler is surface-treated with an appropriate surface treatment agent. Surface treatment can improve the moisture resistance and dispersibility of the inorganic filler. Examples of surface treatment agents include silane coupling agents such as vinyl-based silane coupling agents, epoxy-based silane coupling agents, styryl-based silane coupling agents, (meth)acrylic-based silane coupling agents, amino-based silane coupling agents, isocyanurate-based silane coupling agents, ureido-based silane coupling agents, mercapto-based silane coupling agents, isocyanate-based silane coupling agents, and acid anhydride-based silane coupling agents; non-silane coupling-alkoxysilane compounds such as methyltrimethoxysilane and phenyltrimethoxysilane; silazane compounds; and the like. The surface treatment agent may be used alone or in combination of two or more types.

[0061] Examples of commercially available surface treatment agents include "KBM-403" (3-glycidoxypropyltrimethoxysilane), "KBM-803" (3-mercaptopropyltrimethoxysilane), "KBE-903" (3-aminopropyltriethoxysilane), "KBM-573" (N-phenyl-3-aminopropyltrimethoxysilane), and "SZ-31" (hexamethyldisilazane), all manufactured by Shin-Etsu Chemical Co., Ltd.

[0062] From the viewpoint of improving the dispersibility of the inorganic filler, the degree of surface treatment by the surface treatment agent is preferably within a predetermined range. Specifically, it is preferable that 100% by mass of the inorganic filler is surface-treated with 0.2% to 5% by mass of the surface treatment agent.

[0063] The degree of surface treatment by a surface treatment agent can be evaluated by the amount of carbon per unit surface area of ​​the inorganic filler. From the viewpoint of improving the dispersibility of the inorganic filler, the amount of carbon per unit surface area of ​​the inorganic filler should be 0.02 mg / m². ２ The above is preferred, and 0.1 mg / m² ２ The above is more preferable, 0.2 mg / m² ２The above is even more preferable. On the other hand, the upper limit of the amount of carbon per unit surface area of ​​the inorganic filler is 1 mg / m², from the viewpoint of preventing an increase in the melt viscosity of the resin composition and the melt viscosity in the resin sheet form. ２ The following is preferred: 0.8 mg / m² ２ The following is more preferable: 0.5 mg / m² ２ The following is even more preferable. The amount of carbon per unit surface area of ​​the inorganic filler can be measured after washing the inorganic filler with a solvent (e.g., methyl ethyl ketone (MEK)) after surface treatment. Specifically, a sufficient amount of MEK as the solvent is added to the inorganic filler that has been surface-treated with a surface treatment agent, and ultrasonic cleaning is performed at 25°C for 5 minutes. After removing the supernatant and drying the solids, the amount of carbon per unit surface area of ​​the inorganic filler can be measured using a carbon analyzer. As a carbon analyzer, the "EMIA-320V" manufactured by Horiba, Ltd. can be used.

[0064] When the resin composition contains an inorganic filler, the amount of inorganic filler in the resin composition is, from the viewpoint of significantly obtaining the desired effects of the present invention, for example, 20% by mass or more, preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, even more preferably 55% by mass or more, preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less, when the nonvolatile components in the resin composition are taken as 100% by mass.

[0065] <Thermoplastic Resin> The resin composition may include a thermoplastic resin as an optional component. The thermoplastic resin does not include those that fall under the curable resins described above. The thermoplastic resin may be used alone or in combination of two or more types.

[0066] Examples of thermoplastic resins include phenoxy resins, polyimide resins, polyvinyl acetal resins, polyolefin resins, polybutadiene resins, polyamideimide resins, polyetherimide resins, polysulfone resins, polyethersulfone resins, polyphenylene ether resins, polycarbonate resins, polyetheretherketone resins, and polyester resins. Among these, it is preferable that the thermoplastic resin contains phenoxy resin.

[0067] Examples of phenoxy resins include phenoxy resins having one or more skeletons selected from the group consisting of bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenolacetophenone skeleton, novolac skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, terpene skeleton, and trimethylcyclohexane skeleton. The terminal end of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. Specific examples of phenoxy resins include "1256" and "4250" (both phenoxy resins containing a bisphenol A skeleton) manufactured by Mitsubishi Chemical Corporation; "YX8100" (phenoxy resin containing a bisphenol S skeleton) manufactured by Mitsubishi Chemical Corporation; "YX6954" (phenoxy resin containing a bisphenol acetophenone skeleton) manufactured by Mitsubishi Chemical Corporation; "FX280" and "FX293" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YL7500BH30", "YX6954BH30", "YX7553", "YX7553BH30", "YL7769BH30", "YL6794", "YL7213", "YL7290", "YL7482", and "YL7891BH30" manufactured by Mitsubishi Chemical Corporation; and others. Phenoxy resins may be used individually or in combination of two or more types.

[0068] The weight-average molecular weight (Mw) of the thermoplastic resin is preferably 5,000 or more, more preferably 8,000 or more, even more preferably 10,000 or more, 15,000 or more, or 20,000 or more, preferably 200,000 or less, more preferably 150,000 or less, or 100,000 or less, and even more preferably 80,000 or less, or 60,000 or less. The weight-average molecular weight of the thermoplastic resin is the weight-average molecular weight on a polystyrene basis measured by gel permeation chromatography (GPC).

[0069] When the resin composition contains a thermoplastic resin, the content of the thermoplastic resin in the resin composition is, from the viewpoint of significantly obtaining the desired effects of the present invention, for example, 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.3% by mass or more, even more preferably 0.5% by mass or more or 0.6% by mass or more, and preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, 2% by mass or less or 1% by mass or less.

[0070] When the resin composition contains a thermoplastic resin, the content of the thermoplastic resin in the resin composition is, from the viewpoint of significantly obtaining the desired effects of the present invention, for example, 0.1% by mass or more, preferably 1% by mass or more, more preferably 1.5% by mass or more, even more preferably 2% by mass or more, preferably 15% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, or 3% by mass or less, when the total resin component in the resin composition is taken as 100% by mass.

[0071] <Curing Accelerator> The resin composition may contain a curing accelerator as an optional component. The curing accelerator does not include those corresponding to the curable resins and thermoplastic resins mentioned above. Since the curing accelerator functions as a catalyst for the reaction of the curable resin, it can accelerate the curing of the resin composition. The curing accelerator may be used alone or in combination of two or more types.

[0072] Examples of curing accelerators include amine-based curing accelerators, imidazole-based curing accelerators, phosphorus-based curing accelerators, guanidine-based curing accelerators, metal-based curing accelerators, and urea-based curing accelerators. Among these, it is preferable that the curing accelerator includes an amine-based curing accelerator.

[0073] Examples of amine-based curing accelerators include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclo(5,4,0)-undecene, 1,8-diazabicyclo[5,4,0]undecene-7,4-dimethylaminopyridine, and 2,4,6-tris(dimethylaminomethyl)phenol, with 4-dimethylaminopyridine being preferred. Commercially available amine-based curing accelerators may also be used, such as "DMAP" manufactured by Tokyo Chemical Industries, Ltd., and "PN-50", "PN-23", and "MY-25" manufactured by Ajinomoto Fine Techno Co., Ltd.

[0074] If the resin composition contains a curing accelerator, the content of the curing accelerator in the resin composition is, from the viewpoint of significantly obtaining the desired effects of the present invention, for example, 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.09% by mass or more, even more preferably 0.1% by mass or more, 0.11% by mass or more, 0.12% by mass or more, or 0.13% by mass or more, preferably 3% by mass or less, more preferably 1% by mass or less, even more preferably 0.5% by mass or less, 0.3% by mass or less, or 0.2% by mass or less, when the nonvolatile components in the resin composition are taken as 100% by mass.

[0075] If the resin composition contains a curing accelerator, the content of the curing accelerator in the resin composition is, from the viewpoint of significantly obtaining the desired effects of the present invention, for example, 0.1% by mass or more, preferably 0.2% by mass or more, more preferably 0.3% by mass or more, even more preferably 0.4% by mass or more, preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less or 0.5% by mass or less, when the resin component in the resin composition is considered as 100% by mass.

[0076] <Organic Solvents> The resin composition may contain an organic solvent as an optional component. The organic solvent does not include those corresponding to the curable resins, thermoplastic resins, and curing accelerators mentioned above. The organic solvent may be used alone or in combination of two or more types.

[0077] Examples of organic solvents include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, and γ-butyrolactone; ether solvents such as tetrahydropyran, tetrahydrofuran, 1,4-dioxane, diethyl ether, diisopropyl ether, dibutyl ether, diphenyl ether, and anisole; alcohol solvents such as methanol, ethanol, propanol, butanol, and ethylene glycol; and 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl diglycol acetate, γ-butyrolactone, and methyl methoxypropionate. Examples of solvents include ether ester solvents such as methyl lactate, ethyl lactate, and methyl 2-hydroxyisobutyrate; ether alcohol solvents such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether (butyl carbitol); amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; sulfoxide solvents such as dimethyl sulfoxide; nitrile solvents such as acetonitrile and propionitrile; aliphatic hydrocarbon solvents such as hexane, cyclopentane, cyclohexane, and methylcyclohexane; and aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene.

[0078] When the resin composition contains an organic solvent, the content of the organic solvent in the resin composition is, for example, 10% by mass or more, preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more, preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less, when the total components in the resin composition are considered as 100% by mass.

[0079] Furthermore, in one embodiment, the resin composition does not have to contain an organic solvent. That is, in one embodiment, the content of the organic solvent in the resin composition may be 0% by mass, when the total components in the resin composition are considered to be 100% by mass.

[0080] <Other Additives> The resin composition may contain other additives as optional components in combination with the curable resin, inorganic filler, thermoplastic resin, curing accelerator, and organic solvent described above. Other additives do not include those corresponding to the curable resin, inorganic filler, thermoplastic resin, curing accelerator, and organic solvent described above. Other additives may be used individually or in combination of two or more types.

[0081] Other additives include, for example, organic fillers such as rubber particles; radical polymerization initiators such as peroxide-based radical polymerization initiators and azo-based radical polymerization initiators; organometallic compounds such as organocopper compounds and organozinc compounds; colorants such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium dioxide, and carbon black; polymerization inhibitors such as hydroquinone, catechol, pyrogallol, and phenothiazine; leveling agents such as silicone-based leveling agents and acrylic polymer-based leveling agents; thickeners such as bentonite and montmorillonite; defoamers such as silicone-based defoamers, acrylic-based defoamers, fluorine-based defoamers, and vinyl resin-based defoamers; and UV absorbers such as benzotriazole-based UV absorbers. Examples of additives include: absorbing agents; adhesion enhancers such as urea silane; adhesion enhancers such as triazole-based adhesion enhancers, tetrazole-based adhesion enhancers, and triazine-based adhesion enhancers; antioxidants such as hindered phenol-based antioxidants; fluorescent whitening agents such as stilbene derivatives; surfactants such as fluorine-based surfactants and silicone-based surfactants; flame retardants such as phosphorus-based flame retardants (e.g., phosphate ester compounds, phosphazene compounds, phosphinic acid compounds, red phosphorus), nitrogen-based flame retardants (e.g., melamine sulfate), halogen-based flame retardants, and inorganic flame retardants (e.g., antimony trioxide); stabilizers such as borate-based stabilizers, titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, and carboxylic acid anhydride-based stabilizers; and so on. If the resin composition contains other additives, the content of the components in the resin composition may be determined according to the properties required of the resin composition. Furthermore, the curable resin, inorganic filler, thermoplastic resin, curing accelerator, and organic solvent described above may also have functions such as organic filler, radical polymerization initiator, organometallic compound, colorant, polymerization inhibitor, leveling agent, thickener, defoamer, ultraviolet absorber, adhesion enhancer, adhesion imparterant, antioxidant, fluorescent whitening agent, surfactant, flame retardant, dispersant, and stabilizer. In such cases, such components shall be considered as components of the curable resin, inorganic filler, thermoplastic resin, curing accelerator, and organic solvent described above, rather than as other additives.

[0082] [Method for Manufacturing Resin Compositions] Resin compositions can be manufactured, for example, by mixing components that may be included in a resin composition. The above-mentioned components may be mixed some or all at the same time, or they may be mixed sequentially. The temperature may be set appropriately during the mixing process of each component, and thus heating and / or cooling may be performed temporarily or throughout the process. Furthermore, this manufacturing method may, if necessary, include kneading or stirring (mixing) the resin composition using kneading means such as a three-roll mill, ball mill, bead mill, or sand mill, or stirring means such as a super mixer, planetary mixer, or high-speed rotary mixer.

[0083] Next, before describing in detail the method for manufacturing the substrate of the present invention, we will explain the resin sheet in steps (B) and (C) of the method for manufacturing the substrate of the present invention.

[0084] [Resin Sheet] Using the resin composition described above, a resin sheet for use in the manufacturing method of the substrate of the present invention, that is, a resin sheet for protecting the edges of the substrate, can be manufactured. The present invention also provides such a resin sheet. Hereinafter, the "resin sheet for protecting the edges of the substrate" may be simply referred to as the "resin sheet". The "resin sheet for forming an insulating layer" described later may be the same as or different from the "resin sheet for protecting the edges of the substrate" according to one embodiment of the present invention.

[0085] A resin sheet according to one embodiment of the present invention comprises a support and a resin composition layer formed on the support. The resin composition layer contains the above-mentioned resin composition, and preferably contains only the above-mentioned resin composition.

[0086] The thickness of the resin composition layer in the resin sheet according to one embodiment of the present invention is preferably 1 μm or more, more preferably 5 μm or more, even more preferably 10 μm or more, 15 μm or more, 20 μm or more, 25 μm or more, 30 μm or more, or 35 μm or more, and preferably 100 μm or less, 90 μm or less, 80 μm or less, 70 μm or less, 60 μm or less, or 50 μm or less, from the viewpoint of significantly obtaining the desired effects of the present invention.

[0087] Examples of support materials include thermoplastic resin films, metal foils, and release paper. In one preferred embodiment, the support material is a thermoplastic resin film.

[0088] When a thermoplastic resin film is used as a support, examples of thermoplastic resins that can be used as materials for the thermoplastic resin film include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); polycarbonate (PC); acrylic resins such as polymethyl methacrylate (PMMA); cyclic polyolefins; triacetylcellulose (TAC); polyether sulfide (PES); polyether ketones; and polyimide resins. Among these, from the viewpoint of heat resistance, one or more thermoplastic resins selected from the group consisting of polyester resins and polyimide resins are preferred for the thermoplastic resin film material, one or more selected from the group consisting of polyethylene terephthalate and polyethylene naphthalate are more preferred, and inexpensive polyethylene terephthalate is even more preferred.

[0089] The support may have a matte finish, corona treatment, or antistatic treatment applied to the surface that joins with the resin composition layer. Alternatively, a support with a release layer may be used, which has a release layer on the surface that joins with the resin composition layer. Examples of release agents used in the release layer of the support with a release layer include one or more release agents selected from the group consisting of alkyd resins, polyolefin resins, urethane resins, and silicone resins. Examples of commercially available release agents include "SK-1", "AL-5", and "AL-7" from Lintec Corporation. Furthermore, commercially available support with a release layer may also be used, for example, "Purex" from Toyobo Co., Ltd. and "Unipeel" from Unitika Corporation, which are PET films having a release layer mainly composed of an alkyd resin-based release agent or a polyolefin resin-based release agent.

[0090] The thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, and more preferably in the range of 10 μm to 60 μm. When using a support with a release layer, it is preferable that the overall thickness of the support with the release layer is within the above range.

[0091] In one embodiment, the resin sheet may further include any additional layer as needed. Such an additional layer may be, for example, a protective film provided on the side of the resin composition layer that is not bonded to the support (i.e., the side opposite to the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 75 μm, preferably 1 μm to 40 μm. By laminating the protective film, the adhesion of dust and other debris to the surface of the resin composition layer and scratches can be suppressed.

[0092] [Method for Manufacturing Resin Sheets] A resin sheet according to one embodiment of the present invention can be manufactured using the resin composition described above. The resin sheet can be manufactured, for example, by a method that includes, in this order, the steps of: applying the resin composition onto a support, and drying the resin composition applied onto the support to form a resin composition layer.

[0093] In the method for manufacturing a resin sheet, the resin composition can be applied using a known coating device such as a die coater.

[0094] In the method for manufacturing a resin sheet, drying of the resin composition may be carried out by known methods such as heating or blowing hot air. The drying conditions are not particularly limited, but may be appropriately determined so that the content of the organic solvent in the resin composition layer satisfies a desired numerical range. In one preferred embodiment, the resin composition (and the resin composition layer) can be dried such that the content of the organic solvent in the resin composition layer is preferably 10% by mass or less, more preferably 5% by mass or less, preferably 0.6% by mass or more, and more preferably 1% by mass or more, when the total components in the resin composition layer are considered to be 100% by mass.

[0095] Furthermore, the drying conditions may be appropriately determined so that the melt viscosity of the resin composition layer satisfies a desired numerical range. In one preferred embodiment, the resin composition (and the resin composition layer) can be dried so that the melt viscosity (poise) of the resin composition layer at a temperature of 100°C is preferably 500 or more, more preferably 1,000 or more, even more preferably 1,300 or more, 1,400 or more, or 1,500 or more, preferably 10,000 or less, more preferably 8,000 or less, even more preferably 6,000 or less, even more preferably 5,000 or less, and even more preferably 4,000 or less.

[0096] When the content of the organic solvent in the resin composition layer and / or the melt viscosity of the resin composition layer are within the above-mentioned preferred range, the flow of the resin composition layer at the substrate edge can be further suppressed in step (C) described later, thereby providing more uniform protection to the substrate edge. Furthermore, when the content of the organic solvent in the resin composition layer and / or the melt viscosity of the resin composition layer are within the above-mentioned preferred range, the flow of the resin composition layer at the substrate edge can be further suppressed in step (C) described later, improving the adhesion between the core substrate and the resin composition layer, resulting in a substrate edge with superior resistance to roughening treatment. Moreover, when the content of the organic solvent in the resin composition layer and / or the melt viscosity of the resin composition layer are within the above-mentioned preferred range, the adhesion between the core substrate and the resin composition layer can be improved in step (C) described later, and a substrate edge with superior resistance to roughening treatment can be obtained, resulting in a substrate edge with excellent plating adhesion.

[0097] Furthermore, if the resin composition layer contains a thermosetting resin (preferably an epoxy resin), and the content of the organic solvent in the resin composition layer and / or the melt viscosity of the resin composition layer are within the above-described preferred range, the flow of the resin composition layer at the substrate edge can be further suppressed in step (C) described later, and the adhesion between the core substrate and the resin composition layer can be made particularly good. Also, the good chemical resistance of the thermosetting resin can be enjoyed, resulting in a substrate edge with particularly excellent resistance to roughening treatment (especially roughening treatment by a wet method). Moreover, if the resin composition layer contains a thermosetting resin (preferably an epoxy resin), and the content of the organic solvent in the resin composition layer and / or the melt viscosity of the resin composition layer are within the above-described preferred range, the adhesion between the core substrate and the resin composition layer can be made particularly good in step (C) described later. Also, a substrate edge with particularly excellent resistance to roughening treatment can be obtained, resulting in a substrate edge with particularly excellent plating adhesion.

[0098] In one embodiment, the drying temperature is preferably 70°C or higher, more preferably 80°C or higher, preferably 150°C or lower, more preferably 140°C or lower, even more preferably 130°C or lower, even more preferably 120°C or lower, and even more preferably 110°C or lower.

[0099] In one embodiment, the drying time is preferably 0.5 minutes or more, more preferably 1 minute or more, even more preferably 1.5 minutes or more, 2 minutes or more, preferably less than 10 minutes, more preferably 8 minutes or less, even more preferably 6 minutes or less, or 5 minutes or less.

[0100] The resin sheet can be stored by rolling it up. If the resin sheet has a protective film, it can be used after removing the protective film.

[0101] [Method for Manufacturing a Substrate] The resin sheet described above can be used in the method for manufacturing a substrate of the present invention. The method for manufacturing a substrate of the present invention is characterized by comprising: (A) the step of preparing a core substrate having a first main surface, a second main surface, and an end surface sandwiched between the first main surface and the second main surface; (B) the step of preparing a resin sheet having a support and a resin composition layer provided on the support; and (C) the step of covering the end surface of the core substrate with the resin composition layer of the resin sheet.

[0102] In one embodiment, the method for manufacturing a substrate of the present invention may further include a step of curing a resin composition layer (D) after step (C). In another embodiment, the method for manufacturing a substrate of the present invention may further include a step of removing the support provided by the resin sheet after step (C).

[0103] In one embodiment, the method for manufacturing a substrate of the present invention may further include the steps of forming holes in a cured resin composition layer, roughening the cured resin composition layer, and forming a conductive layer on the cured resin composition layer. In another embodiment, the method for manufacturing a substrate of the present invention may further include the steps of forming an insulating layer, forming holes in the insulating layer, roughening the insulating layer, and forming a conductive layer on the insulating layer. In yet another embodiment, the method for manufacturing a substrate of the present invention may further include the step of providing a semiconductor chip so as to be bonded to the conductive layer.

[0104] As mentioned above, the inventors have found that in a method of applying a varnish-like resin composition to the edge surface of a substrate, the resin composition flows before curing, making it impossible to uniformly protect the edge of the substrate with the cured resin composition. In contrast, according to the method of the present invention described above, the edge surface of the core substrate can be covered with a resin composition layer having a uniform thickness, making it possible to realize a substrate with uniformly protected edges. Furthermore, according to the method of the present invention described above, the flow of the resin composition layer at the edge of the substrate can be suppressed in step (C), and the adhesion between the core substrate and the resin composition layer can be improved, resulting in a substrate edge with excellent resistance to roughening treatment (especially roughening treatment by wet method). Moreover, according to the method of the present invention described above, the edge surface of the core substrate can be covered with a resin composition layer having a uniform thickness, so even when a physical impact is applied to the edge of the substrate, the impact can be mitigated, and thus a substrate with excellent crack resistance can be realized. The steps of the substrate manufacturing method of the present invention will be described in detail below.

[0105] <Process (A)> In process (A), a core substrate is prepared having a first main surface, a second main surface, and an end surface sandwiched between the first main surface and the second main surface.

[0106] The "core substrate" prepared in step (A) may be a glass substrate such as a glass epoxy substrate or a glass composite substrate; an organic substrate such as a polyester substrate, a polyimide substrate, a BT resin substrate, or a thermosetting polyphenylene ether substrate; a metal substrate such as a copper substrate, a titanium substrate, an aluminum substrate, a stainless steel substrate, or a cold-rolled steel sheet (SPCC); a ceramic substrate; a wafer; a flexible substrate; or any other substrate. As the wafer, for example, a semiconductor wafer such as a silicon wafer, a gallium arsenide (GaAs) wafer, an indium phosphide (InP) wafer, a gallium phosphide (GaP) wafer, a gallium nitride (GaN) wafer, a gallium tellurium (GaTe) wafer, a zinc selenium (ZnSe) wafer, or a silicon carbide (SiC) wafer may be used, or a pseudo-wafer may be used. As a pseudo-wafer, for example, a plate-shaped member comprising a mold resin and electronic components embedded in the mold resin may be used. Among these, the core substrate is preferably a glass substrate.

[0107] The core substrate may have a conductive layer on at least one of the first main surface and the second main surface. The conductive layer that the core substrate may have may be patterned. The core substrate may also have an insulating layer on at least one of the first main surface and the second main surface. The core substrate may also have a layer (build-up layer) on at least one of the first main surface and the second main surface in which insulating layers and conductive layers are alternately stacked. When the core substrate has an insulating layer and / or a conductive layer on at least one of the first main surface and the second main surface, the insulating layer and / or conductive layer are formed on at least one of the first main surface and the second main surface, so the side surface of the insulating layer and / or conductive layer does not correspond to the end surface of the core substrate.

[0108] The core substrate may have through-holes penetrating the first main surface and the second main surface. When the core substrate has through-holes penetrating the first main surface and the second main surface, the through-holes are formed inside the core substrate, and therefore the inner walls of the through-holes do not correspond to the end faces of the core substrate.

[0109] The shape of the core substrate is not particularly limited, as long as it comprises a first main surface, a second main surface, and an end surface sandwiched between the first and second main surfaces. In one example, the core substrate may or may not have the same dimensions in the thickness direction. In particular, it is preferable that the core substrate has the same dimensions in the thickness direction.

[0110] The shapes of the first and second main surfaces of the core substrate can be, for example, rectangles, squares, circles, ellipses, approximate rectangles, approximate circles, etc. Among these, the shapes of the first and second main surfaces of the core substrate are preferably rectangles, squares, or approximate rectangles, with rectangles being more preferred.

[0111] In one example, if the shapes of the first and second main surfaces are circular or elliptical, the core substrate may have one continuous end face (i.e., a side face). Also in one example, if the shapes of the first and second main surfaces are rectangular, square, approximately rectangular, or approximately circular, the core substrate may have multiple discontinuous end faces.

[0112] <Step (B)> In Step (B), a resin sheet is prepared comprising a support and a resin composition layer provided on the support. Step (B) may be performed before Step (A) or after Step (A).

[0113] The structure of the support and resin composition layer of the resin sheet prepared in process (B) is as described above.

[0114] The "resin sheet" prepared in step (B) may be a resin sheet that has been stored in advance, or a resin sheet manufactured by the [Method for Manufacturing Resin Sheets] described above. Therefore, in one embodiment, step (B) may include, in this order, a step of coating the resin composition onto a support, and a step of drying the resin composition coated onto the support to form a resin composition layer. Details of the method for coating the resin composition, and drying conditions such as the drying temperature and drying time of the resin composition, are as described above.

[0115] Step (B) may further include a step of cutting the resin sheet according to the size of the end face of the core substrate to be covered. In this specification, the cut resin sheet is also included in the term "resin sheet" in steps (B) and (C).

[0116] In step (B), which is the step of cutting the resin sheet, a known cutting device may be used. Furthermore, the shape of the cut resin sheet is not particularly limited as long as it can cover the end face of the core substrate, and may be, for example, a single sheet. In addition, the step of cutting the resin sheet may further include, for example, a step of making a notch in the single sheet of resin sheet.

[0117] The size of the resin sheet can be appropriately determined according to the size of the end face of the core substrate to be covered. For example, if the resin sheet is in the form of a single sheet, the length of the short axis (width) of the resin sheet depends on the size of the end face of the core substrate to be covered, but is preferably 0.01 mm or more, more preferably 0.1 mm or more, even more preferably 0.5 mm or more, 0.6 mm or more, 0.7 mm or more, 0.8 mm or more, 0.9 mm or more, or 1 mm or more, preferably 40 mm or less, more preferably 30 mm or less, even more preferably 25 mm or less, 20 mm or less, 15 mm or less, or 10 mm or less. Furthermore, in the resin sheet used in step (C) described later, the length of the short axis (width) of the resin composition layer on the resin sheet may be the same as the length of the short axis (width) of the resin sheet. That is, in the resin sheet used in step (C), the length of the short axis of the resin composition layer provided on the resin sheet is preferably 0.01 mm or more, more preferably 0.1 mm or more, even more preferably 0.5 mm or more, 0.6 mm or more, 0.7 mm or more, 0.8 mm or more, 0.9 mm or more, or 1 mm or more, preferably 40 mm or less, more preferably 30 mm or less, even more preferably 25 mm or less, 20 mm or less, 15 mm or less, or 10 mm or less.

[0118] <Process (C)> After processes (A) and (B), in process (C), the end faces of the core substrate are covered with the resin composition layer of the resin sheet.

[0119] There are no particular restrictions on the method of covering the end faces of the core substrate with the resin composition layer of the resin sheet, as long as the end faces of the core substrate are not exposed. For example, if the core substrate has multiple discontinuous end faces, multiple resin sheets may be prepared, and the resin composition layer of each resin sheet may be used to cover each end face of the core substrate.

[0120] The process (C) will be described in detail below, divided into two parts: process (C) for a core substrate without an insulating layer on the first main surface and the second main surface (hereinafter sometimes referred to as "the first embodiment"), and process (C) for a core substrate with an insulating layer on at least one of the first main surface and the second main surface (hereinafter sometimes referred to as "the second embodiment"). However, process (C) is not limited to the first embodiment and the second embodiment illustrated below.

[0121] <Step (C) in the First Embodiment> In step (C) in the first embodiment, in a core substrate without an insulating layer on the first main surface and the second main surface, the end face of the core substrate is covered with a resin composition layer provided by a resin sheet.

[0122] Step (C) in the first embodiment is not particularly limited as long as the end face of the core substrate is not exposed. In one embodiment, step (C) in the first embodiment includes a step of joining the resin composition layer of the resin sheet to the end face of the core substrate. Hereinafter, this embodiment may be referred to as the "first coating step in step (C) according to the first embodiment". In the first coating step in step (C) according to the first embodiment, the method of joining the resin composition layer may be, for example, by pressing the resin sheet to the end face of the core substrate from the support side. Examples of a member for pressing the resin composition layer of the resin sheet to the end face of the core substrate (hereinafter sometimes referred to as the "pressing member") include a metal plate (such as a SUS end plate), a metal plate with an elastic material such as rubber (for example, silicone rubber) covering its main surface, a metal roll (such as a SUS roll), or a rubber roll (such as a metal roll with an elastic material such as rubber covering it). If the crimping member does not have an elastic material, instead of pressing the crimping member directly onto the resin sheet, it may be pressed via an elastic material such as rubber to ensure that the resin composition layer of the resin sheet conforms sufficiently to the edge surface of the core substrate. The process of crimping the resin sheet from the support side (crimping process) may be performed using a commercially available laminator.

[0123] The bonding pressure during joining is preferably in the range of 0.098 MPa to 1.77 MPa, more preferably in the range of 0.29 MPa to 1.47 MPa, and the bonding time is preferably in the range of 20 seconds to 400 seconds, more preferably in the range of 30 seconds to 300 seconds. The bonding of the resin sheets may be carried out under normal pressure (atmospheric pressure) or under reduced pressure conditions.

[0124] In step (C) of the first embodiment, the first coating step may be performed by heating and pressing a resin sheet onto the end face of the core substrate from the support side. This heating and pressing step may be performed after the step of pressing the resin sheet from the support side (pressing step) described above. For example, the resin sheet may be heated and pressed from the support side using a heated pressing member (hereinafter sometimes referred to as "heat-pressing member"). If the heating and pressing member does not have an elastic material, instead of directly pressing the heating and pressing member onto the resin sheet, a heat-resistant elastic material (for example, heat-resistant rubber such as heat-resistant silicone rubber) may be used to ensure that the resin composition layer of the resin sheet conforms sufficiently to the end face of the core substrate.

[0125] The heat-sealing temperature during joining is preferably in the range of 60°C to 160°C, more preferably in the range of 80°C to 140°C, the heat-sealing pressure is preferably in the range of 0.098 MPa to 1.77 MPa, more preferably in the range of 0.29 MPa to 1.47 MPa, and the heat-sealing time is preferably in the range of 20 seconds to 400 seconds, more preferably in the range of 30 seconds to 300 seconds.

[0126] In particular, the first coating step in step (C) according to the first embodiment is preferably carried out by a hot roll lamination method from the viewpoint of obtaining the effects of the present invention in a remarkable manner. That is, the first coating step in step (C) according to the first embodiment is preferably carried out using a heated metal roll (such as a SUS roll) or a heated rubber roll (such as a metal roll coated with a heat-resistant elastic material).

[0127] With respect to the first coating step in step (C) of the first embodiment, when the end face of the core substrate is coated with the resin composition layer provided by the resin sheet, there may be a surface of the resin composition layer provided by the resin sheet that is exposed and does not come into contact with the end face of the core substrate. In such cases, it is preferable to fold the resin sheet from the support side to join the exposed surface of the resin composition layer with at least one of the first main surface and the second main surface provided by the core substrate. The process of folding the resin sheet is not particularly limited and can be carried out using, for example, a metal roll such as a SUS roll (a heated metal roll if necessary), or a rubber roll such as a metal roll coated with an elastic material such as rubber (a heated rubber roll coated with a heat-resistant elastic material if necessary). Furthermore, when using a metal roll to fold the resin sheet, instead of directly pressing the metal roll onto the resin sheet, an elastic material such as rubber (or a heat-resistant elastic material (e.g., heat-resistant rubber)) may be used to ensure that the resin composition layer of the resin sheet conforms sufficiently to at least one of the first main surface and the second main surface of the core substrate.

[0128] In one embodiment, step (C) in the first aspect includes, in this order: (C1) a step of joining a part of the resin composition layer of the resin sheet to either the first main surface or the second main surface of the core substrate, and (C2) a step of covering the end surface of the core substrate with the remaining part of the resin composition layer of the resin sheet by folding the resin sheet from the support side. Hereinafter, this embodiment may be referred to as the "second coating step in step (C) according to the first aspect". With respect to the second coating step in step (C) according to the first aspect, there are no particular limitations on the method of joining the resin composition layer in step (C1), and for example, it may be done by pressing the resin sheet from the support side to either the first main surface or the second main surface of the core substrate. Examples of the pressing member include a metal plate (SUS end plate, etc.), a metal plate with an elastic material such as rubber covering its main surface, a metal roll (SUS roll, etc.), or a rubber roll (a metal roll with an elastic material such as rubber covering it, etc.). If the crimping member does not have an elastic material, instead of pressing the crimping member directly onto the resin sheet, it may be pressed via an elastic material such as rubber (or a heat-resistant elastic material (e.g., heat-resistant rubber)) so that the resin composition layer of the resin sheet conforms sufficiently to either the first main surface or the second main surface of the core substrate.

[0129] The bonding pressure during joining is preferably in the range of 0.098 MPa to 1.77 MPa, more preferably in the range of 0.29 MPa to 1.47 MPa, and the bonding time is preferably in the range of 20 seconds to 400 seconds, more preferably in the range of 30 seconds to 300 seconds. The bonding of the resin sheets may be carried out under normal pressure (atmospheric pressure) or under reduced pressure conditions.

[0130] With respect to the second coating step in step (C) according to the first embodiment, step (C1) may be performed by heating and pressing a resin sheet from the support side onto either the first main surface or the second main surface of the core substrate. This heating and pressing step may be performed after the step (pressing step) of pressing the resin sheet from the support side as described above. Step (C1) may be performed, for example, by heating and pressing the resin sheet from the support side using a heating and pressing member. Note that instead of directly pressing the heating and pressing member onto the resin sheet, the pressing may be performed via a heat-resistant elastic material (for example, heat-resistant rubber) so that the resin composition layer of the resin sheet follows the end surface of the core substrate sufficiently.

[0131] The heat-sealing temperature during joining is preferably in the range of 60°C to 160°C, more preferably in the range of 80°C to 140°C, the heat-sealing pressure is preferably in the range of 0.098 MPa to 1.77 MPa, more preferably in the range of 0.29 MPa to 1.47 MPa, and the heat-sealing time is preferably in the range of 20 seconds to 400 seconds, more preferably in the range of 30 seconds to 300 seconds.

[0132] The second coating step in step (C) according to the first embodiment includes step (C2), after step (C1), a step in which the resin sheet is folded from the support side to cover the end face of the core substrate with the remaining resin composition layer of the resin sheet. Step (C2) is not particularly limited as long as the end face of the core substrate is not exposed. Step (C2) can be carried out using, for example, a metal roll such as a SUS roll (a heated metal roll if necessary), or a rubber roll such as a metal roll coated with an elastic material such as rubber (a heated rubber roll coated with a heat-resistant elastic material if necessary). Furthermore, when a metal roll is used in step (C2), instead of pressing the metal roll directly onto the resin sheet, the press may be made via an elastic material such as rubber so that the resin composition layer of the resin sheet follows the end face of the core substrate sufficiently.

[0133] With respect to the second coating step in step (C) according to the first embodiment, when the end face of the core substrate is covered with the remaining portion of the resin composition layer provided by the resin sheet, there may be a surface on the remaining portion of the resin composition layer provided by the resin sheet that is not in contact with the end face of the core substrate and is exposed. In such a case, it is preferable to further include a step of joining the exposed surface of the resin composition layer to the other of the first main surface and the second main surface provided by the core substrate by folding the resin sheet from the support side (C3). Step (C3) is not particularly limited as long as the exposed surface of the resin composition layer can be joined to the other of the first main surface and the second main surface provided by the core substrate, and can be carried out, for example, in the same manner as step (C2).

[0134] If the second coating step in step (C) according to the first embodiment includes step (C3), it is preferable that the second coating step in step (C) according to the first embodiment further includes, after step (C3), a step of (C4) pressing a resin sheet from the support side onto both the first main surface and the second main surface of the core substrate. Step (C4) is not particularly limited and may be carried out by, for example, a vacuum lamination method. In the vacuum lamination method, the heat-pressing temperature is preferably in the range of 60°C to 160°C, more preferably in the range of 80°C to 140°C, the heat-pressing pressure is preferably in the range of 0.098 MPa to 1.77 MPa, more preferably in the range of 0.29 MPa to 1.47 MPa, and the heat-pressing time is preferably in the range of 20 seconds to 400 seconds, more preferably in the range of 30 seconds to 300 seconds. Furthermore, step (C4) may preferably be carried out under reduced pressure conditions of 26.7 hPa or less.

[0135] Step (C4) can be carried out using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include the vacuum pressure laminator manufactured by Meiki Seisakusho Co., Ltd. and the batch-type vacuum pressure laminator manufactured by Nikko Materials Co., Ltd.

[0136] <Step (C) in the second embodiment> In step (C) in the second embodiment, in a core substrate having an insulating layer on at least one of the first main surface and the second main surface, the end face of the core substrate is covered with a resin composition layer provided by a resin sheet.

[0137] Step (C) in the second embodiment is not particularly limited, as long as the end face of the core substrate is not exposed. In one embodiment, step (C) in the first embodiment includes a step of bonding the resin composition layer of the resin sheet to the end face of the core substrate. The method of bonding the resin composition layer may be the same as the method and conditions for bonding the resin composition layer described in the section <Step (C) in the second embodiment> above. Therefore, step (C) in the second embodiment may be performed by pressing the resin sheet to the end face of the core substrate from the support side, or by heating and pressing the resin sheet from the support side. Alternatively, step (C) in the second embodiment may be performed by pressing the resin sheet to the end face of the core substrate from the support side, and then heating and pressing the resin sheet from the support side. The method and conditions for pressing and heating in the first embodiment may be the same as those for the first coating step in step (C) in the first embodiment.

[0138] In particular, step (C) in the second embodiment is preferably carried out by a hot roll lamination method from the viewpoint of significantly obtaining the effects of the present invention. That is, step (C) in the second embodiment is preferably carried out using a heated metal roll (such as a SUS roll) or a heated rubber roll (such as a metal roll coated with heat-resistant rubber).

[0139] With respect to step (C) in the second embodiment, when the end face of the core substrate is covered with the resin composition layer of the resin sheet, there may be exposed surfaces in the resin composition layer of the resin sheet that do not come into contact with the end face and insulating layer (and, if necessary, the conductive layer) of the core substrate. In such cases, the exposed surface of the resin composition layer may be joined to at least one of the first main surface and the second main surface of the core substrate, or to the insulating layer (and, if necessary, the conductive layer) by folding the resin sheet from the support side. The step of folding the resin sheet from the support side is not particularly limited and can be carried out using, for example, a metal roll such as a SUS roll (a heated metal roll if necessary), or a rubber roll such as a metal roll coated with heat-resistant rubber (a heated rubber roll coated with a heat-resistant elastic material if necessary). Furthermore, when using a metal roll in the process of folding the resin sheet from the support side, instead of directly pressing the metal roll onto the resin sheet, the press may be made via an elastic material such as rubber so that the resin composition layer of the resin sheet follows sufficiently the first main surface and the second main surface of the core substrate, or the insulating layer (and, if necessary, the conductive layer). The process of pressing the resin sheet from the support side (pressing process) may be performed using a commercially available laminator.

[0140] <Step (D)> In one embodiment, the method for manufacturing the substrate of the present invention may further include a step of curing the coated resin composition layer after step (C).

[0141] The resin composition layer can be cured by a method suitable for the resin composition, such as thermal curing (heat treatment) or photocuring (exposure treatment). Alternatively, the resin composition layer may be cured by a combination of thermal curing and photocuring.

[0142] For example, when a thermosetting resin composition, such as a resin composition containing a thermosetting resin, is used, the curing of the resin composition may proceed as thermal curing. In this case, step (D) may include a step of thermal curing the resin composition layer. The thermal curing conditions for the resin composition layer may also vary depending on the type of resin composition. For example, the curing temperature may be preferably 120°C to 240°C, more preferably 150°C to 220°C, and even more preferably 170°C to 210°C. The curing time may be preferably 5 minutes to 120 minutes, more preferably 10 minutes to 100 minutes, and even more preferably 15 minutes to 100 minutes.

[0143] When the resin composition layer is to be heat-cured, step (D) may include a step of preheating the resin composition layer at a temperature lower than the curing temperature before the heat curing. In one embodiment, prior to heat curing the resin composition layer, the resin composition layer may be preheated at a temperature of, for example, 50°C to 150°C, preferably 60°C to 140°C, more preferably 70°C to 130°C for, for example, 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.

[0144] On the other hand, when a photocurable resin composition is used, such as a resin composition containing a photocurable resin, the curing of the resin composition can proceed as photocuring. In this case, step (D) may include a step of photocuring the resin composition layer. The photocuring conditions for the resin composition layer may also vary depending on the type of resin composition. For example, the resin composition layer in the irradiated area can be photocured by an exposure treatment in which an active light is irradiated onto the resin composition layer. Examples of active light include ultraviolet light, visible light, electron beams, X-rays, etc., with ultraviolet light being particularly preferred. The irradiation dose of ultraviolet light is, for example, 10 mJ / cm². ２ ~10,000mJ / cm ２ This is possible. The exposure process may be performed through the support, or after the support has been removed.

[0145] <Other steps> The support provided by the resin sheet may be removed immediately after step (C). Also, if the substrate manufacturing method of the present invention includes step (D), the support provided by the resin sheet may be removed after step (D). Also, if the substrate manufacturing method of the present invention includes a step of roughening the cured resin composition layer, it is preferable to remove the support provided by the resin sheet before performing the step of roughening the cured resin composition layer. Therefore, in one embodiment, the substrate manufacturing method of the present invention further includes a step of removing the support provided by the resin sheet after step (C). Also, in one preferred embodiment, the substrate manufacturing method of the present invention further includes a step of removing the support provided by the resin sheet after step (C) and before the step of roughening the cured resin composition layer. Also, if the substrate manufacturing method of the present invention includes a step of forming an insulating layer using a resin sheet for forming an insulating layer, the removal of the support provided by the resin sheet for protecting the edges of the substrate and the removal of the support provided by the resin sheet for forming the insulating layer may be performed simultaneously or not simultaneously. There are no particular limitations on the method of removing the support; for example, the support may be removed by peeling it off.

[0146] In the first embodiment, a resin composition layer provided by a resin sheet may be present on at least one of the first main surface and the second main surface provided by the core substrate. For example, with respect to the first coating step in step (C) of the first embodiment, if the step includes a step of joining the exposed surface of the resin composition layer to at least one of the first main surface and the second main surface provided by the core substrate by folding the resin sheet from the support side, then a portion of the coated resin composition layer may be joined and present on at least one of the first main surface and the second main surface provided by the core substrate. Also, for example, with respect to the second coating step in step (C) of the first embodiment, if step (C1) includes a portion of the coated resin composition layer being joined to either the first main surface or the second main surface provided by the core substrate, then if step (C3) is included, another portion of the coated resin composition layer may be joined and present on the other of the first main surface and the second main surface provided by the core substrate.

[0147] In a second embodiment, the resin composition layer of the resin sheet may be present on at least one of the first main surface and the second main surface of the core substrate, or on an insulating layer (and, if necessary, a conductive layer). For example, if the process includes a step of joining the exposed surface of the resin composition layer to at least one of the first main surface and the second main surface of the core substrate, or on an insulating layer (and, if necessary, a conductive layer) by folding the resin sheet from the support side, then a portion of the covered resin composition layer may be joined to and present on at least one of the first main surface and the second main surface of the core substrate, or on an insulating layer (and, if necessary, a conductive layer).

[0148] Hereinafter, "a part of a coated resin composition layer that is bonded to at least one of the first main surface and the second main surface of the core substrate, or to an insulating layer (and, if necessary, a conductive layer)" may simply be referred to as the "coating layer."

[0149] Thus, when a coating layer is present on the core substrate, by subjecting it to step (D), a cured product of the coated resin composition layer is formed on at least one of the first main surface and the second main surface of the core substrate. Hereinafter, the "cured product of the coated resin composition layer formed on at least one of the first main surface and the second main surface of the core substrate" may simply be referred to as the "cured layer".

[0150] As mentioned above, in the manufacturing method of substrates, a resin composition layer was sometimes omitted around the edges of the main surface of the substrate in order to suppress resin seepage. In such conventional techniques, dead space was created because wiring could not be provided on the edges of the main surface of the substrate.

[0151] In contrast to such conventional technologies, the substrate manufacturing method of the present invention can achieve even higher wiring density by utilizing the space on the coating layer or cured layer. Specifically, according to an embodiment that includes a step of forming wiring (conductor layer) on the coating layer or cured layer, resin seepage can be suppressed and the edges of the substrate can be uniformly protected while achieving even higher wiring density, thus significantly contributing to the miniaturization and performance improvement of electronic devices. Furthermore, in the substrate manufacturing method of the present invention, even when a resin sheet for forming the insulating layer is laminated on the core substrate during the formation of the insulating layer, resin seepage can be further suppressed by the coating layer or cured layer, thus significantly contributing to the control of the thickness of the insulating layer.

[0152] The following describes in detail the additional steps that the substrate manufacturing method of the present invention may further include, divided into cases where the substrate manufacturing method according to the first embodiment includes other steps (hereinafter sometimes referred to as "modified version of the first embodiment") and cases where the substrate manufacturing method according to the second embodiment includes other steps (hereinafter sometimes referred to as "modified version of the second embodiment").

[0153] <Modifications in the First Embodiment> Taking advantage of the above-mentioned advantages, modifications in the first embodiment may further include a step of forming holes such as via holes and through holes in the cured layer after step (D). The method for forming the holes can be selected according to factors such as the composition of the resin composition used to form the cured layer. The step of forming the holes may include, for example, a processing method such as drilling, laser processing, or plasma processing, and among these, laser processing is preferred. The step of forming the holes may, for example, involve irradiating the cured layer with laser light after peeling off the support to form the holes, or irradiating the cured layer with laser light through the support to form the holes. The dimensions and shape of the holes formed in the cured layer may be appropriately determined according to the design of the substrate.

[0154] Taking advantage of the above-mentioned benefits, a modification of the first embodiment may further include a step of roughening the hardened layer after step (D). The roughening treatment can roughen the surface of the hardened layer. Furthermore, the roughening treatment can remove smear (resin residue) from the hardened layer. Therefore, this roughening treatment is sometimes called "desmear treatment". If the modification of the first embodiment includes a step of forming holes in the hardened layer, smear may be formed in the holes of the hardened layer. Therefore, if the modification of the second embodiment includes a step of forming holes in the hardened layer, it is preferable to remove the smear by roughening the hardened layer.

[0155] The procedure and conditions for roughening the hardened layer are not particularly limited, and known procedures and conditions commonly used when forming the insulating layer of a substrate can be employed. For example, the insulating layer can be roughened using a wet method in which swelling treatment with a swelling solution, roughening treatment with an oxidizing agent, and neutralization treatment with a neutralizing solution are carried out in that order; or a dry method such as plasma.

[0156] Examples of swelling solutions used in the wet method include alkaline solutions and surfactant solutions, with alkaline solutions being preferred. Sodium hydroxide solution and potassium hydroxide solution are more preferred as the alkaline solution. Examples of commercially available swelling solutions include "Swelling Dip Securigant P" and "Swelling Dip Securigant SBU" manufactured by Atotec Japan. The swelling treatment with the swelling solution can be carried out, for example, by immersing the insulating layer in a swelling solution at 30°C to 90°C for 1 to 20 minutes. From the viewpoint of suppressing the swelling of the resin in the cured layer to an appropriate level, it is preferable to immerse the cured layer in a swelling solution at 40°C to 80°C for 5 to 15 minutes.

[0157] Examples of oxidizing agents used in the wet process include alkaline permanganate solutions obtained by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. The oxidation treatment with an oxidizing agent such as an alkaline permanganate solution is preferably carried out by immersing the hardened layer in an oxidizing agent solution heated to 60°C to 100°C for 10 to 30 minutes. Furthermore, the concentration of permanganate in the alkaline permanganate solution is preferably 5% to 10% by mass. Examples of commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact CP" and "Dosing Solution Securigans P" manufactured by Atotec Japan.

[0158] For the wet process, an acidic aqueous solution is preferred as the neutralizing solution. A commercially available example is "Reduction Solution Securigant P" manufactured by Attec Japan. The neutralization treatment with the neutralizing solution can be carried out by immersing the treated surface, which has been oxidized with an oxidizing agent, in a neutralizing solution at 30°C to 80°C for 5 to 30 minutes. From the viewpoint of workability, it is preferable to immerse the hardened layer, which has been oxidized with an oxidizing agent, in a neutralizing solution at 40°C to 70°C for 5 to 20 minutes.

[0159] In the dry method, for example, the hardened layer can be treated using plasma generated by introducing a gas into a plasma generator. There are no particular restrictions on the method of generating the plasma, and examples include microwave plasma generated by microwaves, high-frequency plasma using high-frequency waves, atmospheric pressure plasma generated under atmospheric pressure, and vacuum plasma generated under vacuum, with vacuum plasma generated under vacuum being preferred.

[0160] The type of gas used for plasma (the type of gas that is plasma-generated) is not particularly limited as long as it can roughen the surface of the hardened layer (and remove smears generated in holes as needed), for example, gases containing fluorine atoms, N ２ and O ２ It is preferable to use a gas containing any of the following. Examples of gases containing fluorine atoms include F ２ CF ４ , C ２ F６ SF ６ Examples include gases containing fluorine atoms, N ２ and O ２ In addition to any of the above, other gases such as Ar may also be included. Among these, gases that can be turned into plasma include gases containing fluorine atoms, N ２ and O ２ Preferably, it contains one of the following: a gas containing a fluorine atom, and O ２ It is more preferable to include O ２ And, N ２ and CF ４ A mixed gas containing at least one of the following is more preferable: ２ and CF ４ A mixed gas containing the following is even more preferable.

[0161] When using a mixed gas as the gas species to be plasma-generated, the mixing ratio (N ２ and O ２ The gas containing any of the above / other gases (unit: sccm) is preferably 1 / 0.01 to 1 / 100, more preferably 1 / 0.5 to 1 / 10, and even more preferably 1 / 1 to 1 / 5.

[0162] The duration of the roughening treatment by the dry method using plasma is not particularly limited, but is preferably 30 seconds or more, more preferably 60 seconds or more, 90 seconds or more, or 120 seconds or more. The upper limit of the duration of the roughening treatment by the dry method is preferably 10 minutes or less, more preferably 5 minutes or less, from the viewpoint of easily achieving a hardened layer with low surface roughness after the roughening treatment.

[0163] Plasma-based dry roughening treatment can be performed using commercially available dry desmearing equipment. Among commercially available dry desmearing equipment, examples suitable for circuit board manufacturing include plasma dry etching equipment from Oxford Instruments, microwave plasma equipment from Nissin, and atmospheric pressure plasma etching equipment from Sekisui Chemical Co., Ltd.

[0164] In one embodiment, the arithmetic mean roughness (Ra) of the hardened layer surface after roughening treatment is preferably 500 nm or less, more preferably 400 nm or less, and even more preferably 300 nm or less or 250 nm or less. The lower limit of the arithmetic mean roughness (Ra) of the hardened layer surface after roughening treatment is not particularly limited, but is preferably 30 nm or more, more preferably 40 nm or more, and even more preferably 50 nm or more. The arithmetic mean roughness (Ra) of the hardened layer surface can be measured using a non-contact surface roughness meter.

[0165] Taking advantage of the above-mentioned benefits, a modification of the first embodiment may further include a step of forming a first conductive layer on the hardened layer. If a modification of the first embodiment includes one or more steps selected from the group consisting of a step of forming holes in the hardened layer and a step of roughening the hardened layer, it is preferable that the step of forming the first conductive layer is performed after performing one or more steps selected from such group.

[0166] The conductive material used for the first conductive layer is not particularly limited. In a preferred embodiment, the conductive layer contains one or more metals selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. The first conductive layer may 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 group (e.g., nickel-chromium alloy, copper-nickel alloy, and copper-titanium alloy). In particular, from the viewpoint of versatility in conductive layer formation, cost, and ease of patterning, the first conductive layer is preferably a single-metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or an alloy layer of nickel-chromium alloy, copper-nickel alloy, or copper-titanium alloy, more preferably a single-metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or an alloy layer of nickel-chromium alloy, and even more preferably a single-metal layer of copper.

[0167] The first conductive layer may have a single-layer structure, or it may have a multi-layer structure including two or more single-metal layers or alloy layers made of different types of metals or alloys. When the first conductive layer has a multi-layer structure, the layer in contact with the hardened layer is preferably a single-metal layer of chromium, zinc, or titanium, or an alloy layer of nickel-chromium alloy.

[0168] The thickness of the first conductor layer depends on the substrate design, but is preferably 3 μm to 35 μm, and more preferably 5 μm to 30 μm.

[0169] The first conductor layer may be formed by plating. For example, a conductor layer having a desired wiring pattern can be formed by plating the surface of the hardened layer using conventionally known techniques such as the semi-additive method or the fully additive method. From the viewpoint of ease of manufacture, the semi-additive method is preferred. Below, an example of forming the first conductor layer by the semi-additive method is shown.

[0170] First, an electroless plating layer (plating seed layer) is formed on the surface of the hardened layer by electroless plating. Next, a mask pattern is formed on the formed electroless plating layer, exposing a portion of the electroless plating layer corresponding to the desired wiring pattern. After forming an electroplating layer on the exposed electroless plating layer by electroplating, the mask pattern is removed. Subsequently, the unnecessary electroless plating layer can be removed by etching to form a conductor layer having the desired wiring pattern.

[0171] As another example, the first conductor layer may be formed using metal foil. When forming the conductor layer using metal foil, it is preferable to perform the step of forming the first conductor layer before step (D). For example, after forming the coating layer, the support provided by the resin sheet for protecting the edges of the substrate is removed, and the metal foil is laminated onto the exposed surface of the coating layer. The lamination of the coating layer and the metal foil may be carried out by a vacuum lamination method. The heating and pressing temperature, heating and pressing pressure, and heating and pressing time in the vacuum lamination method may be the same conditions as those described in step (C4) above. Next, in step (D), the coating layer is cured to form a cured layer. After that, the metal foil on the cured layer can be used to form a conductor layer having a desired wiring pattern by known techniques such as the subtractive method or the modified semi-additive method. The metal foil can be manufactured by known methods such as the electrolytic method or the rolling method. Examples of commercially available metal foils include HLP foil and JXUT-III foil manufactured by JX Metals Corporation; and 3EC-III foil and TP-III foil manufactured by Mitsui Mining & Smelting Co., Ltd.

[0172] When a first conductive layer is formed on a hardened layer, a modification of the first embodiment may further include a step of performing an annealing treatment after the formation of the first conductive layer. Annealing treatment can improve the adhesion between the hardened layer and the first conductive layer. Annealing treatment of the first conductive layer can be performed, for example, by heating at 150°C to 210°C for 20 to 180 minutes.

[0173] A modification of the first embodiment may further include a step of forming an insulating layer on at least one of the first main surface and the second main surface of the core substrate. The step of forming the insulating layer may be carried out by a forming method that includes, for example, applying a resin composition for forming an insulating layer onto at least one of the first main surface and the second main surface of the core substrate and curing the applied resin composition, but it is preferable to carry out the step using a resin sheet for forming an insulating layer. The resin sheet for forming an insulating layer comprises a support and a resin composition layer provided on the support. As the support of the resin sheet for forming an insulating layer, for example, one similar to the support described in the [Resin Sheet] section above may be used. Furthermore, the resin composition layer of the resin sheet for forming an insulating layer may have the same composition as the resin composition layer of the resin sheet prepared in step (B), or it may have a different composition from the resin composition layer of the resin sheet prepared in step (B).

[0174] A method for forming an insulating layer using a resin sheet for forming an insulating layer includes, for example, the steps of laminating a resin sheet for forming an insulating layer on at least one of a first main surface and a second main surface of a core substrate, and curing the resin composition layer of the resin sheet for forming an insulating layer.

[0175] The process of laminating the resin sheet for forming the insulating layer may be performed on only one of the first main surface and the second main surface of the core substrate, or on both the first main surface and the second main surface of the core substrate. The process of laminating the resin sheet for forming the insulating layer is carried out so that the resin composition layer of the resin sheet for forming the insulating layer is bonded to the core substrate. This lamination may be performed, for example, by using a heat-pressing member to heat-press the resin sheet for forming the insulating layer to the core substrate from the support side. Note that instead of directly pressing the heat-pressing member onto the resin sheet, the heat-resistant elastic material (for example, heat-resistant rubber) may be used to ensure that the resin composition layer of the resin sheet conforms sufficiently to the edge surface of the core substrate.

[0176] The process of laminating resin sheets for forming the insulating layer may be carried out by a vacuum lamination method. The heating and pressing temperature, heating and pressing pressure, and heating and pressing time in the vacuum lamination method may be the same conditions as those described in step (C4) above. The process of laminating resin sheets for forming the insulating layer may also be carried out using a commercially available vacuum laminator.

[0177] A modification of the first embodiment may further include a step of smoothing the resin sheets for forming the insulating layer after laminating the resin sheets for forming the insulating layer, by pressing a heat-sealing member from the support side under normal pressure (atmospheric pressure). The pressing conditions for the smoothing treatment may be the same as the conditions for heat-sealing in the lamination of the resin sheets for forming the insulating layer described above. Furthermore, the step of laminating the resin sheets for forming the insulating layer and the step of smoothing the resin sheets for forming the edge layer may be performed continuously using a commercially available vacuum laminator.

[0178] The process of curing the resin composition layer of the resin sheet for forming the insulating layer can be carried out by thermal curing. The thermal curing conditions for the resin composition layer may also vary depending on the type of resin composition. For example, the curing temperature is preferably 120°C to 240°C, more preferably 150°C to 220°C, and even more preferably 170°C to 210°C. The curing time may be preferably 5 minutes to 120 minutes, more preferably 10 minutes to 100 minutes, and even more preferably 15 minutes to 100 minutes.

[0179] A variation of the first embodiment may further include a step of preheating the resin composition layer of the resin sheet for forming the insulating layer at a temperature lower than the curing temperature before the resin composition layer is heat-cured. For example, prior to heat-curing the resin composition layer of the resin sheet for forming the insulating layer, the resin composition layer may be preheated at a temperature of, for example, 50°C to 150°C, preferably 60°C to 140°C, more preferably 70°C to 130°C for, for example, 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. If the process includes a step of smoothing the resin sheet for forming the edge layer, the preheating step may be performed after the smoothing step.

[0180] When a resin sheet for forming an insulating layer is used, a modification of the first embodiment may include a step of removing the support provided on the resin sheet for forming the insulating layer after the resin sheet has been laminated. The removal of the support may be performed immediately after the step of laminating the resin sheet for forming the insulating layer, or immediately after the step of curing the resin composition layer provided on the resin sheet for forming the insulating layer. Furthermore, if the modification of the first embodiment includes a step of roughening the insulating layer, it is preferable to remove the support provided on the resin sheet for forming the insulating layer before the step of roughening the insulating layer.

[0181] A modification of the first embodiment may further include a step of forming holes such as via holes and through holes in the insulating layer after the insulating layer has been formed. The method for forming the holes can be selected according to factors such as the composition of the resin composition used to form the insulating layer. The dimensions and shape of the holes formed in the insulating layer may be appropriately determined according to the design of the substrate. The step of forming holes in the insulating layer in the first embodiment may be the same as the step of forming holes in the cured layer described in the modification of the first embodiment described above. In addition, in the modification of the first embodiment, the step of forming holes in the cured layer and the step of forming holes in the insulating layer may be performed simultaneously or separately.

[0182] A modification of the first embodiment may further include a step of roughening the insulating layer after it has been formed. The roughening treatment can roughen the surface of the insulating layer. The roughening treatment can also remove smear (resin residue) from the insulating layer. If the modification of the first embodiment includes a step of forming holes in the insulating layer, smear may be formed in the holes of the insulating layer. Therefore, if the modification of the second embodiment includes a step of forming holes in the insulating layer, it is preferable to remove the smear by roughening the insulating layer. In addition, in the modification of the first embodiment, the step of roughening the cured layer and the step of roughening the insulating layer may be performed simultaneously or separately.

[0183] The procedure and conditions for roughening the insulating layer are not particularly limited and may be the same as those for roughening the hardened layer described above.

[0184] In one preferred embodiment, the arithmetic mean roughness (Ra) of the insulating layer surface after roughening treatment is preferably within the preferred range of the arithmetic mean roughness (Ra) of the hardened layer surface after roughening treatment described above.

[0185] A modification of the first embodiment may further include a step of forming a second conductor layer on the insulating layer. If the modification of the first embodiment includes one or more steps selected from the group consisting of a step of forming holes in the insulating layer and a step of roughening the insulating layer, it is preferable that the step of forming the second conductor layer is performed after performing one or more steps selected from such group. In addition, in the modification of the first embodiment, the steps of forming the first conductor layer and forming the second conductor layer may be performed simultaneously or separately.

[0186] The conductive material used for the second conductive layer is not particularly limited. The preferred range for the second conductive layer is the same as the preferred range for the first conductive layer described above.

[0187] The second conductor layer may have a single-layer structure, or it may have a multi-layer structure including two or more single-metal layers or alloy layers made of different types of metals or alloys. When the second conductor layer has a multi-layer structure, the layer in contact with the insulating layer is preferably a single-metal layer of chromium, zinc, or titanium, or an alloy layer of nickel-chromium alloy.

[0188] The thickness of the second conductive layer depends on the substrate design, but is preferably 3 μm to 35 μm, and more preferably 5 μm to 30 μm.

[0189] The second conductor layer may be formed by plating. For example, a conductor layer having a desired wiring pattern can be formed by plating the surface of the insulating layer using conventionally known techniques such as the semi-additive method or the fully additive method. From the viewpoint of ease of manufacture, the semi-additive method is preferred. A specific method for forming the second conductor layer by the semi-additive method can be applied, for example, by replacing "hardened layer" with "insulating layer" in the above-described method for forming the first conductor layer by the semi-additive method.

[0190] As another example, the second conductor layer may be formed using metal foil. When forming the second conductor layer using metal foil, the step of forming the second conductor layer is preferably carried out between the step of laminating a resin sheet for forming an insulating layer onto at least one of the first and second main surfaces of the core substrate and the step of curing the resin composition layer of the resin sheet for forming the insulating layer. For example, after the step of laminating the resin sheet for forming the insulating layer, the support provided by the resin sheet for forming the insulating layer is removed, and metal foil is laminated onto the surface of the exposed resin composition layer. The lamination of the resin composition layer and the metal foil may be carried out by a vacuum lamination method. The heating and pressing temperature, heating and pressing pressure, and heating and pressing time in the vacuum lamination method can be the same conditions as those described in step (C4) above. Next, the resin composition layer is cured to form an insulating layer. After that, a conductor layer having a desired wiring pattern can be formed using the metal foil on the insulating layer by known techniques such as the subtractive method or the modified semi-additive method. As stated above, metal foil can be manufactured by known methods, and details of commercially available metal foil are provided.

[0191] When a second conductor layer is formed on an insulating layer, a modification of the first embodiment may further include a step of performing an annealing treatment after the formation of the second conductor layer. Annealing treatment can improve the adhesion between the insulating layer and the second conductor layer. The conditions for annealing the second conductor layer may be the same as those for annealing the first conductor layer. In the modification of the first embodiment, the steps of annealing the first conductor layer and annealing the second conductor layer may be performed simultaneously or separately.

[0192] A modification of the first embodiment is that each of the above-described steps may be performed only once or repeated two or more times. For example, a modification of the first embodiment may involve repeatedly performing the steps of forming an insulating layer, forming holes in the insulating layer, roughening the insulating layer, and forming a conductor layer to manufacture a circuit board having a multilayer structure such as a multilayer printed wiring board having multiple insulating layers and conductor layers.

[0193] A modification of the first embodiment may include a step of providing a semiconductor chip so as to be bonded to a first conductor layer and / or a second conductor layer. For example, when manufacturing a circuit board for a semiconductor chip package that includes a semiconductor chip, a modification of the first embodiment may further include a step of providing a semiconductor chip. The step of providing a semiconductor chip may employ appropriate conditions that enable conductive connection between the terminal electrodes of the semiconductor chip and the first conductor layer and / or second conductor layer formed on the hardened layer and / or insulating layer. The step of providing a semiconductor chip may employ, for example, conditions used in flip-chip mounting. The semiconductor chip may also be bonded via an insulating adhesive or by reflow soldering. Furthermore, the step of providing a semiconductor chip may, if necessary, fill the provided semiconductor chip with mold underfill material. Another modification of the first embodiment may further include, for example, a step of forming a sealing layer, a step of forming a solder resist layer, a step of dicing the manufactured substrate into individual pieces, and so on.

[0194] <Modifications in the Second Embodiment> Taking advantage of the above-mentioned advantages, the modification in the second embodiment may further include a step of forming holes such as via holes and through holes in the hardened layer after step (D). The step of forming holes in the hardened layer that may be included in the modification in the second embodiment may be the same as the step described in the modification in the first embodiment described above.

[0195] Taking advantage of the above-mentioned benefits, the modification in the second embodiment may further include a step of roughening the hardened layer after step (D). The step of roughening the hardened layer that may be included in the modification in the second embodiment may be the same as the step described in the modification in the first embodiment described above.

[0196] Taking advantage of the above-mentioned benefits, a modification of the second embodiment may further include a step of forming a third conductive layer on the hardened layer. If a modification of the second embodiment includes one or more steps selected from the group consisting of a step of forming holes in the hardened layer and a step of roughening the hardened layer, it is preferable that the step of forming the third conductive layer is performed after performing one or more steps selected from such group.

[0197] The conductive material used for the third conductive layer is not particularly limited. The preferred range for the third conductive layer is the same as the preferred range for the first conductive layer described above.

[0198] The third conductive layer may have a single-layer structure, or it may have a multi-layer structure including two or more single-metal layers or alloy layers made of different types of metals or alloys. When the third conductive layer has a multi-layer structure, the layer in contact with the hardened layer is preferably a single-metal layer of chromium, zinc, or titanium, or an alloy layer of nickel-chromium alloy.

[0199] The thickness of the third conductive layer depends on the substrate design, but is preferably 3 μm to 35 μm, and more preferably 5 μm to 30 μm.

[0200] The third conductor layer may be formed by plating. For example, a conductor layer having a desired wiring pattern can be formed by plating the surface of the hardened layer using conventionally known techniques such as the semi-additive method or the fully additive method. From the viewpoint of ease of manufacture, the semi-additive method is preferred. The specific method for forming the third conductor layer by the semi-additive method may be the same as the method for forming the first conductor layer by the semi-additive method, which may include, for example, modifications of the first embodiment.

[0201] As another example, the third conductive layer may be formed using metal foil. The specific method for forming the third conductive layer using metal foil may be the same as the method for forming the first conductive layer using metal foil, which may include, for example, variations of the first embodiment.

[0202] When a third conductive layer is formed on the hardened layer, the modification of the second embodiment may further include a step of performing an annealing treatment after the formation of the third conductive layer. Annealing treatment can improve the adhesion between the hardened layer and the third conductive layer. The conditions for annealing the third conductive layer may be the same as the conditions for annealing the first conductive layer, which may be included in the modification of the first embodiment.

[0203] A modification of the second embodiment may further include a step of forming holes, such as via holes and through holes, in an insulating layer provided on at least one of the first main surface and the second main surface of the core substrate. The step of forming holes in the insulating layer in the second embodiment may be the same as the step of forming holes in the cured layer described in the modification of the first embodiment described above. In addition, in the modification of the second embodiment, the step of forming holes in the cured layer and the step of forming holes in the insulating layer may be performed simultaneously or separately.

[0204] A modification in the second embodiment may further include a step of roughening an insulating layer provided on at least one of the first main surface and the second main surface of the core substrate. The step of roughening the insulating layer in the second embodiment may be the same as the step of roughening the hardened layer described in the modification of the first embodiment described above. In addition, in the modification of the second embodiment, the step of roughening the hardened layer and the step of roughening the insulating layer may be performed simultaneously or separately.

[0205] A modification of the second embodiment may further include a step of forming a fourth conductor layer on the insulating layer. If the modification of the second embodiment includes one or more steps selected from the group consisting of a step of forming holes in the insulating layer and a step of roughening the insulating layer, it is preferable that the step of forming the fourth conductor layer is performed after performing one or more steps selected from such group. The step of forming the fourth conductor layer, which may be included in the modification of the second embodiment, may be the same as the step of forming the first conductor layer on the hardened layer as described in the modification of the first embodiment described above. In addition, in the modification of the second embodiment, the steps of forming the third conductor layer and forming the fourth conductor layer may be performed simultaneously or separately.

[0206] When a fourth conductor layer is formed on the insulating layer, the modification of the second embodiment may further include a step of performing an annealing treatment after the formation of the fourth conductor layer. Annealing treatment can improve the adhesion between the insulating layer and the fourth conductor layer. The conditions for the annealing treatment that may be included in the modification of the second embodiment may be the same as the conditions for the annealing treatment of the first conductor layer described in the modification of the first embodiment described above.

[0207] With regard to a modification of the second embodiment, there are cases in which an insulating layer is not formed on either the first main surface or the second main surface of the core substrate. In such cases, the modification of the second embodiment may further include the step of forming an arbitrary insulating layer (an arbitrary first insulating layer) on the main surface of the core substrate on the side where the insulating layer is not formed.

[0208] The steps for forming any first insulating layer that may be included in the modifications of the second embodiment may be the same as the method for forming an insulating layer using a resin sheet for forming an insulating layer, as described in the modifications of the first embodiment described above. That is, when forming any first insulating layer, the modifications of the second embodiment may include the steps of laminating a resin sheet for forming an insulating layer on the main surface of the core substrate on the side where an insulating layer is not formed, and curing the resin composition layer provided on the resin sheet for forming an insulating layer.

[0209] Furthermore, a modification of the second embodiment may further include the step of forming an arbitrary insulating layer (an arbitrary second insulating layer) on the third and / or fourth conductor layers after forming the third and / or fourth conductor layers.

[0210] The steps for forming an arbitrary second insulating layer, which may be included in the modifications of the second embodiment, may be the same as the method for forming an insulating layer using a resin sheet for forming an insulating layer, as described in the modifications of the first embodiment described above. That is, the modifications of the second embodiment may include, when forming an arbitrary second insulating layer, the steps of laminating a resin sheet for forming an insulating layer on a third conductor layer and / or a fourth conductor layer, and curing the resin composition layer provided on the resin sheet for forming an insulating layer.

[0211] In a modified example of the second embodiment, when forming an arbitrary insulating layer including an arbitrary first insulating layer and an arbitrary second insulating layer, if an insulating layer-forming resin sheet is used, the modified example of the second embodiment may include a step of removing the support provided on the insulating layer-forming resin sheet after lamination. The removal of the support may be performed immediately after the step of laminating the insulating layer-forming resin sheet, or immediately after the step of curing the resin composition layer provided on the insulating layer-forming resin sheet. Furthermore, if the modified example of the second embodiment includes a step of roughening the arbitrary insulating layer after it has been formed, it is preferable to remove the support provided on the insulating layer-forming resin sheet before the step of roughening the arbitrary insulating layer.

[0212] A modification in the second embodiment is that each of the above-described steps may be performed only once or repeated two or more times. For example, a modification in the second embodiment may involve repeatedly performing the steps of forming holes in the insulating layer, roughening the insulating layer, forming a conductor layer, and forming an arbitrary insulating layer to manufacture a circuit board having a multilayer structure such as a multilayer printed wiring board having multiple insulating layers and conductor layers.

[0213] A modification in the second embodiment may include a step of providing a semiconductor chip so as to be bonded to a third conductor layer and / or a fourth conductor layer. The step of providing a semiconductor chip that may be included in a modification in the second embodiment may be the same as the step of providing a conductor chip as described in the modification in the first embodiment described above. Furthermore, a modification in the second embodiment may further include a step of forming a sealing layer, a step of forming a solder resist layer, a step of dicing the manufactured substrate into individual pieces, etc., similar to the modification in the first embodiment.

[0214] [Characteristics of the manufactured substrate] The substrate manufacturing method of the present invention provides a substrate manufacturing method that can uniformly protect the substrate edges. For example, as described in the section <Test Example 3: Evaluation of film thickness uniformity> below, a substrate manufactured by the manufacturing method of the present invention is placed in an oven at 180°C and heated for 30 minutes. A cross-sectional observation is performed on the substrate after heating. The thickness t of the cured resin composition layer perpendicular to the substrate edge is measured at the corner of the substrate edge (the boundary between the upper or lower surface of the substrate and the edge). Ｅ The thickness t of the cured resin composition layer perpendicular to the edge of the substrate at the center of the edge of the substrate (equally distanced from the top and bottom surfaces on the edge of the substrate). Ｃ Regarding, Ｅ The size is t Ｃ It is preferable that it be greater than 0.95 times the size of [the object].

[0215] The substrate manufacturing method of the present invention can provide a substrate with excellent crack resistance. For example, as described in the section "Test Example 4: Evaluation of Crack Resistance" below, a substrate manufactured by the manufacturing method of the present invention is placed in an oven at 180°C and heated for 30 minutes. After heating, the substrate is placed in a metal rack and fixed in place so that the distance between the bottom surface of the rack and the end face of the substrate placed on the bottom surface of the rack is 1 cm. Next, the fixing of the substrate is released and the end face of the substrate is brought to rest on the bottom surface of the rack. In this case, it is preferable that no cracks occur in the core substrate within the substrate.

[0216] The substrate manufacturing method of the present invention provides substrate edges with excellent resistance to roughening treatment. With substrate edges having such characteristics, even when applied to a process including a roughening treatment after process (C) or process (D), it is possible to suppress the shedding of the substrate edges. Specifically, when forming a conductive layer on the substrate edges or on an insulating layer provided on a core substrate, even when the substrate edges are subjected to roughening treatment, it is possible to suppress the shedding of the substrate edges, and thus the substrate edges can be uniformly protected even after the roughening treatment process. For example, as described in the section "Test Example 5: Evaluation of Roughening Treatment Resistance" below, a substrate manufactured by the manufacturing method of the present invention is placed in an oven at 180°C and heated for 30 minutes. After heating, the substrate is subjected to roughening treatment. When the edge surface of the substrate after roughening treatment is observed, it is preferable that the cured resin composition layer remains on part or all of the edge surface of the substrate, and more preferably that it remains on all of the edge surface of the substrate. Also, when the four corners of the substrate after roughening treatment are observed, it is preferable that the core substrate is not exposed at the four corners of the substrate.

[0217] The substrate manufacturing method of the present invention can provide substrate edges with excellent plating adhesion. With substrate edges having such characteristics, the substrate edges can function as a base for the plated conductor layer. As described above, the substrate manufacturing method of the present invention can uniformly protect the substrate edges, so that a plating seed layer can be uniformly provided on the substrate edges (i.e., plating defects caused by unprotected areas at the substrate edges can be suppressed), and thus good adhesion between the substrate edges and the plated conductor layer can be achieved. For example, as described in the section "Test Example 6: Evaluation of Plating Adhesion" below, a substrate manufactured by the manufacturing method of the present invention is placed in an oven at 180°C and heated for 30 minutes. After heating, the substrate is subjected to a roughening treatment. Next, an electroless copper plating layer is formed on the cured resin composition layer after the roughening treatment. In such a case, when the end face of the substrate is observed, it is preferable that the electroless copper plating layer is formed on part or all of the cured resin composition layer at the substrate end face, and it is more preferable that the electroless copper plating layer is uniformly formed on all of the cured resin composition layer at the substrate end face.

[0218] Examples of substrates manufactured by the substrate manufacturing method of the present invention include printed circuit boards and circuit boards such as semiconductor chip packages. Examples of semiconductor chip packages include FC-CSP, MIS-BGA packages, ETS-BGA packages, Fan-out type WLP (Wafer Level Package), Fan-in type WLP, Fan-out type PLP (Panel Level Package), and Fan-in type PLP. In these semiconductor chip packages, in addition to steps (A), (B), and (C) above, it is preferable to form a rewiring formation layer as an insulating layer using a cured product obtained by curing the resin composition layer provided in the resin sheet for forming the insulating layer described above. However, the circuit board is not limited to those exemplified herein.

[0219] [Semiconductor Device] A semiconductor device according to one embodiment of the present invention comprises a substrate manufactured by the manufacturing method described above. Examples of such semiconductor devices include various semiconductor devices used in electrical products (e.g., computers, mobile phones, smartphones, tablet devices, wearable devices, digital cameras, medical equipment, and televisions) and vehicles (e.g., motorcycles, automobiles, trains, ships, and aircraft).

[0220] As described above, a semiconductor device according to one embodiment of the present invention comprises a substrate manufactured by the manufacturing method described above. A semiconductor device according to one embodiment of the present invention can be manufactured by a method including the manufacturing method for the substrate of the present invention. More specifically, a manufacturing method for a semiconductor device according to one embodiment of the present invention is a manufacturing method for a semiconductor device comprising a substrate; characterized in that the substrate is manufactured by a manufacturing method comprising: (A) a step of preparing a core substrate having a first main surface, a second main surface, and an end surface sandwiched between the first main surface and the second main surface; (B) a step of preparing a resin sheet having a support and a resin composition layer provided on the support; and (C) a step of covering the end surface of the core substrate with the resin composition layer of the resin sheet.

[0221] The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these examples. In the following description, "parts" and "%" refer to "parts by mass" and "mass%" respectively, unless otherwise specified. Unless otherwise specified, the temperature and pressure conditions were room temperature (25°C) and atmospheric pressure (1 atm).

[0222] <Formulation Example 1: Formulation of Varnish-like Resin Composition 1> 20 parts of biphenyl-type epoxy resin (NC-3000, manufactured by Nippon Kayaku Co., Ltd.), 2 parts of bisphenol-type epoxy resin (ZX-1059, manufactured by Nippon Steel Chemical & Material Co., Ltd., a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin in a 1:1 ratio), 5 parts of triazine skeleton-containing phenol resin (LA-3018-50P, manufactured by DIC Corporation, a propylene glycol monomethyl ether solution with 50% by mass of non-volatile components), 70 parts of activated ester resin (HPC-8000-65T, manufactured by DIC Corporation, a toluene solution with 65% by mass of non-volatile components), phenoxy resin (YX6954BH, manufactured by Mitsubishi Chemical Corporation) 30", 5 parts of a methyl ethyl ketone (MEK) / cyclohexanone mixed solution containing 30% by mass of nonvolatile components, 150 parts of inorganic filler 1 (spherical silica "SOC2" manufactured by Admatex, surface-treated with 0.6 parts of a silane coupling agent having an N-phenyl-3-aminopropyl group ("KBM-573" manufactured by Shin-Etsu Chemical Co., Ltd., average particle size 0.5 μm), 0.3 parts of a curing accelerator ("DMAP" manufactured by Tokyo Chemical Industry Co., Ltd., 4-dimethylaminopyridine), and 125 parts of methyl ethyl ketone (MEK) were stirred at room temperature (25°C) until a homogeneous solution was obtained to obtain a varnish-like resin composition 1.

[0223] <Formulation Example 2: Formulation of Varnish-like Resin Composition 2> In Formulation Example 1, 1) the amount of biphenyl-type epoxy resin ("NC-3000" manufactured by Nippon Kayaku Co., Ltd.) was changed from 20 parts to 10 parts, 2) 2 parts of bisphenol-type epoxy resin ("ZX-1059" manufactured by Nippon Steel Chemical & Material Co., Ltd.) were replaced with 10 parts of another biphenyl-type epoxy resin ("NC-3000H" manufactured by Nippon Kayaku Co., Ltd.), and 3) the amount of inorganic filler 1 (spherical silica surface-treated with a silane coupling agent) was changed from 150 parts to 90 parts. Varnish-like resin composition 2 was obtained in the same manner as in Formulation Example 1, except for the above items.

[0224] The composition of the resin compositions obtained in each formulation example is shown in Table 1 below.

[0225]

[0226] <Manufacturing Example 1: Manufacturing of Resin Sheet 1> A PET film (Panac Corporation's "NP-38-A", 38 μm thick) treated with a silicone-based release agent was prepared as a support.

[0227] Using an applicator (SA-201, manufactured by Tester Sangyo Co., Ltd.), the varnish-like resin composition 1 obtained in Formulation Example 1 was applied to the release surface of the support. Next, the support coated with the resin composition 1 was placed in a gear oven at 100°C and dried for 3 minutes. Through this operation, a resin sheet 1 having a resin composition layer with a thickness of 40 μm was obtained.

[0228] <Manufacturing Example 2: Manufacturing of Resin Sheet 2> In Manufacturing Example 1, the drying time was changed from 3 minutes to 2 minutes. Except for the above, the same procedure as in Example 1 was performed to obtain Resin Sheet 2.

[0229] <Manufacturing Example 3: Manufacturing of Resin Sheet 3> In Manufacturing Example 1, the drying time was changed from 3 minutes to 4 minutes. Except for the above, the same procedure as in Example 1 was performed to obtain Resin Sheet 3.

[0230] <Manufacturing Example 4: Manufacturing of Resin Sheet 4> In Manufacturing Example 1, the resin composition obtained in Formulation Example 1 was changed to resin composition 2 obtained in Formulation Example 2. Except for the above, the same procedure as in Example 1 was performed to obtain resin sheet 4.

[0231] <Manufacturing Example 5: Manufacturing of Resin Sheet 5> In Manufacturing Example 1, the drying time was changed from 3 minutes to 10 minutes. Except for the above, the same procedure as in Example 1 was performed to obtain Resin Sheet 5.

[0232] <Test Example 1: Measurement of Organic Solvent Content in Resin Composition Layer> In the resin sheets 1 to 5 obtained in Production Examples 1 to 5, each resin sheet was cut into 10 cm x 10 cm sections to obtain test pieces for measuring the organic solvent content. The mass of these test pieces was then measured. In addition, the support used in the production of the resin sheets was cut into 10 cm x 10 cm sections to obtain support pieces, and the mass of these support pieces was measured. The mass W of the resin composition layer was obtained by subtracting the mass of the support from the mass of the test pieces. ０ We found [g].

[0233] Next, the test specimen obtained above was placed in an oven at 190°C and heated for 20 minutes. The mass of the test specimen after heat treatment was measured, and the mass of the support was subtracted from the mass of the test specimen after heat treatment to obtain the mass W of the resin composition layer after heat treatment. １ [g] was determined. Since the mass of the support used in the manufacturing example does not change with heat treatment, the mass W of the resin composition layer before and after heat treatment was determined. ０ and W １ Using the following formula (1), the mass reduction rate a [mass%] of the resin composition layer due to heat treatment was calculated. Formula (1): a = (W ０ -W １ ) / W ０ ×100

[0234] In Table 2 below, the value of the mass loss rate a calculated from formula (1) is recorded as the content of the organic solvent in the resin composition layer.

[0235] <Test Example 2: Measurement of Melt Viscosity of Resin Composition Layer at 100°C> From the resin sheets 1 to 5 obtained in Production Examples 1 to 5, multiple resin composition layers were stacked from each resin sheet and processed into pellets to obtain pellet-shaped samples with a thickness of 18 mm and a g g for measuring melt viscosity.

[0236] The melt viscosity at 100°C was measured for pelletized samples using a dynamic viscoelasticity analyzer (Rheosol-G3000, manufactured by UBM). Specifically, the temperature was increased from a starting temperature of 60°C to 200°C at a heating rate of 5°C / min, and the dynamic viscoelasticity was measured under measurement conditions of a temperature interval of 2.5°C, a frequency of 1 Hz, and a strain of 1 deg. After measuring the dynamic viscoelasticity, a graph was created with temperature on the x-axis and melt viscosity on the y-axis, and the melt viscosity at 100°C of the pelletized samples was calculated.

[0237] The drying times of the resin sheets obtained in each manufacturing example, as well as the results of Test Examples 1 and 2, are shown in Table 2 below.

[0238]

[0239] The resin sheets 1 to 5 obtained in manufacturing examples 1 to 5 were each cut to a width of 1 cm.

[0240] <Example 1> A core substrate (hereinafter sometimes referred to as "core substrate 1") was prepared, on which an insulating layer and wiring (conductor pattern) were formed on a glass substrate (300 mm in length, 300 mm in width, 0.7 mm in thickness). Core substrate 1 has a top surface measuring 300 mm in length and 300 mm in width as a first main surface, and a bottom surface measuring 300 mm in length and 300 mm in width as a second main surface. One of the four end faces of core substrate 1 was selected. A 1 cm wide resin sheet 1 was placed on the selected end face such that the extension direction of the resin sheet 1 and the thickness direction of core substrate 1 were perpendicular, the resin composition layer of the resin sheet 1 covered the selected end face, and that areas not in contact with core substrate 1 were created on both the top and bottom sides of core substrate 1 on a surface perpendicular to the thickness direction of the resin composition layer of the resin sheet 1. Next, a 1 cm wide resin sheet 1 was temporarily attached to the selected end face of the core substrate 1 by using a soldering iron to heat-press the resin sheet 1 from the support side.

[0241] Using a thermal roll laminator (MRK-650Y model manufactured by MCK Corporation), the temporarily attached resin sheet 1 was laminated to the end face at a roll pressure of 0.5 MPa, a feed rate of 0.5 m / min, and a roll temperature of 100°C. At the same time, the portion of the resin composition layer of the resin sheet 1 that was not in contact with the end face of the core substrate 1 was folded so that it was in contact with the upper and lower surfaces of the core substrate 1. Through this operation, a resin sheet 1 with a width of 1 cm covered one end face of the core substrate 1.

[0242] The same operation was performed on the remaining three end faces of the core substrate 1 as was performed on the selected end face. As a result of this operation, a 1 cm wide resin sheet 1 covered each of the four end faces of the core substrate 1.

[0243] A core substrate 1, with its four end faces covered by a resin sheet 1, was placed in a 180°C oven and heated for 30 minutes. This operation thermally cured the resin composition layer on the resin sheet 1, forming a protective layer made of the cured resin composition layer. Next, the support was peeled off to obtain a substrate sample 1 in which the protective layer covered the four end faces of the core substrate 1.

[0244] <Example 2> In Example 1, when forming the protective layer, a resin sheet 2 with a width of 1 cm was used instead of a resin sheet 1 with a width of 1 cm. Except for the above, a substrate sample 2 was obtained in which the protective layer covered all four end faces of the core substrate 1, in the same manner as in Example 1.

[0245] <Example 3> In Example 1, when forming the protective layer, a resin sheet 3 with a width of 1 cm was used instead of a resin sheet 1 with a width of 1 cm. Except for the above, a substrate sample 3 was obtained in which the protective layer covered all four end faces of the core substrate 1, in the same manner as in Example 1.

[0246] <Example 4> In Example 1, when forming the protective layer, a resin sheet 4 with a width of 1 cm was used instead of a resin sheet 1 with a width of 1 cm. Except for the above, a substrate sample 4 was obtained in which the protective layer covered all four end faces of the core substrate 1, in the same manner as in Example 1.

[0247] <Example 5> A core substrate (hereinafter sometimes referred to as "core substrate 2") without an insulating layer formed on a glass substrate (300 mm in length, 300 mm in width, 0.7 mm in thickness) was prepared. The upper surface of core substrate 2 was designated as the first main surface, and the lower surface of core substrate 2 was designated as the second main surface. One of the four end faces of core substrate 2 was selected. A 1 cm wide resin sheet 1 was placed on the selected end face such that the extending direction of the resin sheet 1 and the thickness direction of core substrate 2 were perpendicular, the resin composition layer of the resin sheet 1 covered the selected end face, and that areas not in contact with core substrate 2 were created on both the upper and lower sides of core substrate 2 in a plane perpendicular to the thickness direction of the resin composition layer of the resin sheet 1. Next, a 1 cm wide resin sheet 1 was temporarily attached to the selected end face of the core substrate 2 by using a soldering iron to heat-press the resin sheet 1 from the support side.

[0248] Using a thermal roll laminator (MRK-650Y model, manufactured by MCK Corporation), the temporarily attached resin sheet 1 was laminated to the end face at a roll pressure of 0.2 MPa, a feed rate of 0.5 m / min, and a roll temperature of 100°C. At the same time, the portion of the resin composition layer of the resin sheet 1 that was not in contact with the end face of the core substrate 2 was folded so that it was in contact with the upper and lower surfaces of the core substrate 2. Through this operation, a 1 cm wide resin sheet 1 covered one end face of the core substrate 2.

[0249] The same operation was performed on the remaining three end faces of the core substrate 2 as was performed on the selected end face. As a result of this operation, a 1 cm wide resin sheet 1 covered each of the four end faces of the core substrate 2.

[0250] A core substrate 2, with its four end faces covered by a resin sheet 1, was placed in a 180°C oven and heated for 30 minutes. This operation thermally cured the resin composition layer on the resin sheet 1, forming a protective layer made of the cured resin composition layer. Next, the support was peeled off to obtain a substrate sample 5 in which the protective layer covered the four end faces of the core substrate 2.

[0251] <Example 6> A core substrate 2 was prepared in the same manner as in Example 5. One of the four end faces of the core substrate 2 was selected. On the upper surface of the core substrate 2, a location 5 mm away from the boundary between the upper surface of the core substrate 2 and the selected end face was selected. The location 5 mm away from the selected end face on the upper surface of the core substrate 2 is sometimes simply referred to as the "selected location on the upper surface of the core substrate 2". Next, a 1 cm wide resin sheet 1 was placed on the selected location on the upper surface of the core substrate 2 such that the resin composition layer of the resin sheet 1 covers the selected location on the upper surface of the core substrate 2, and that a region that does not come into contact with the core substrate 2 is created on the selected end face side of the core substrate 2 in a plane perpendicular to the thickness direction of the resin composition layer of the resin sheet 1. The region in the resin composition layer of the resin sheet 1 that does not come into contact with the core substrate 2 is sometimes referred to as "region α". Next, a 1 cm wide resin sheet 1 was temporarily attached to the selected location on the upper surface of the core substrate 2 by using a soldering iron to heat-press the resin sheet 1 from the support side.

[0252] Next, in the resin sheet 1 temporarily attached to a portion of the upper surface of the core substrate 2, the region (region α) where the resin composition layer is not in contact with the core substrate 2 was folded from the support side of the resin sheet 1 along the selected end face side of the core substrate 2. As a result of this operation, a portion of region α covered the selected end face of the core substrate 2, and a region (remaining portion of region α) was created that was not in contact with the selected end face of the core substrate 2. The region (remaining portion of region α) that is not in contact with the selected end face of the core substrate 2 is sometimes referred to as "region β".

[0253] Next, the region (region β) of the resin composition layer that was not in contact with the core substrate 2 was folded from the support side of the resin sheet 1 along the underside of the core substrate 2. This operation resulted in a structure where the entire region β was in contact with the underside of the core substrate 2. Then, the region β of the resin composition layer of the resin sheet 1 was temporarily attached to the underside of the core substrate 2 by applying pressure of 0.5 MPa from the support side of the resin sheet 1.

[0254] In the resin composition layer of the resin sheet 1, the portions temporarily attached to the upper and lower surfaces of the core substrate 2 were pressed together at a pressure of 0.5 MPa from the support side of the resin sheet 1 via an elastic member using a chamber-type vacuum laminator (Nikko Materials Co., Ltd. 2-stage build-up laminator CVP700). Through this operation, a 1 cm wide resin sheet 1 covered one end face of the core substrate 2.

[0255] The same operation was performed on the remaining three end faces of the core substrate 2 as was performed on the selected end face. As a result of this operation, a 1 cm wide resin sheet 1 covered each of the four end faces of the core substrate 2.

[0256] A core substrate 2, with its four end faces covered by a resin sheet 1, was placed in a 180°C oven and heated for 30 minutes. This operation thermally cured the resin composition layer on the resin sheet 1, forming a protective layer made of the cured resin composition layer. Next, the support was peeled off to obtain a substrate sample 6 in which the protective layer covered the four end faces of the core substrate 2.

[0257] <Example 7> In Example 5, when forming the protective layer, a resin sheet 5 with a width of 1 cm was used instead of a resin sheet 1 with a width of 1 cm. Except for the above, a substrate sample 7 was obtained in which the protective layer covered all four end faces of the core substrate 1, in the same manner as in Example 5.

[0258] <Comparative Example 1> The core substrate 2 was used as the substrate sample 8.

[0259] <Comparative Example 2> The resin composition 1 obtained in Formulation Example 1 was applied to the four end faces of the core substrate 2 by a roll coating method. Through this operation, the resin composition 1 covered the four end faces of the core substrate 2.

[0260] A core substrate 2, whose four end faces were coated with resin composition 1, was placed in an oven at 180°C and heated for 30 minutes to heat-cur the resin composition 1 and form a protective layer. Through this operation, a substrate sample 9 was obtained in which the four end faces of the core substrate 2 were coated with a protective layer made of cured resin composition 1.

[0261] <Comparative Example 3> A photosensitive resin (Shin-Etsu Silicone Co., Ltd.'s radical polymerization type high-reliability silicone adhesive "KER-4301-UV") was applied to the four end faces of the core substrate 2 by a roll coating method. Through this operation, the photosensitive resin covered the four end faces of the core substrate 2.

[0262] A core substrate 2, whose four end faces are coated with photosensitive resin, is subjected to a projection exposure system (Iwasaki Electric Co., Ltd.'s "UV curing system with conveyor") at a rate of 4,000 mJ / cm². ２ The photosensitive resin was photocured by ultraviolet exposure. Through this procedure, a substrate sample 10 was obtained in which the four end faces of the core substrate 2 were covered with a protective layer made of cured photosensitive resin.

[0263] <Test Example 3: Evaluation of Film Thickness Uniformity> For substrate samples 1-7, 9, and 10 obtained in Examples 1-7 and Comparative Examples 2 and 3, two opposing end faces were selected from the four coated end faces. Each substrate sample was cut along a plane parallel to the two selected end faces, and the shape of the protective layer was observed from the cross-sectional direction. In the cross-sectional observation of the protective layer of each substrate sample, the thickness of the protective layer perpendicular to the end face of the substrate sample was measured at the corner of the end face (i.e., the boundary between the upper or lower surface of the substrate sample and the end face), and t Ｅ It was recorded as follows: Regarding the thickness of the protective layer at the corners of the edge face of the substrate sample, if the thickness on the top side and the thickness on the bottom side are different, the one with the smaller thickness is used. Ｅ They hired him for that role.

[0264] In cross-sectional observation of the protective layer of each substrate sample, the thickness of the protective layer perpendicular to the edge of the substrate sample was measured at the center of the edge of the substrate sample (i.e., at a position equidistant from the top and bottom surfaces of the edge of the substrate sample), and t Ｃ It was recorded as follows: Measured thickness of the protective layer t Ｅ and t Ｃ The uniformity of the protective layer thickness was evaluated using the following criteria. Note that in Comparative Example 1, no protective layer was formed, and the core substrate 2 was used as is; therefore, it is indicated with "-" in Table 5 below. [Evaluation Criteria for Uniformity of Protective Layer Thickness] "○": Measured t Ｅ and t Ｃ However, t Ｅ / t Ｃ > Satisfies the relationship of 0.95. "×": Measured t Ｅ and t Ｃ However, t Ｅ / t Ｃ The relationship ≤ 0.95 is satisfied.

[0265] <Test Example 4: Evaluation of Crack Resistance> Substrate samples 1 to 10 obtained in Examples 1 to 7 and Comparative Examples 1 to 3 were each placed in a metal rack, and the presence or absence of cracks was checked. Specifically, each substrate sample was fixed and positioned so that the two opposing end faces of each substrate sample were parallel to the bottom surface of the metal rack, and the distance between the bottom surface of the rack and the end face of each substrate sample placed on the bottom surface of the rack was 1 cm. Next, the fixing of each substrate sample was released, so that the end face of each substrate sample touched the bottom surface of the rack.

[0266] The above procedure was performed on each substrate sample, and after each substrate sample landed on the bottom of the rack, it was collected and visually inspected. Using the observation results, the crack resistance of each substrate sample was evaluated according to the following criteria. [Criteria for evaluating substrate crack resistance] "○": No cracks occur in the glass substrate (core substrate 1 or core substrate 2). "×": Cracks occur in the glass substrate (core substrate 1 or core substrate 2).

[0267] <Test Example 5: Evaluation of Roughening Treatment Resistance> (5-1) Substrate samples 1 to 10 obtained in Swelling Treatment Examples 1 to 7 and Comparative Examples 1 to 3 were each placed in a swelling solution at 60°C (an aqueous solution containing "Swelling Dip Securigant P" manufactured by Atotec Japan and "Sodium Hydroxide" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and vibrated at 60°C for 10 minutes. Then, each substrate sample was washed with pure water to complete the swelling treatment.

[0268] (5-2) Each substrate sample after roughening and swelling treatment was placed in an oxidizing agent solution at 80°C (an aqueous solution containing "Concentrate Compact CP" manufactured by Atotec Japan and "Sodium Hydroxide" manufactured by Fujifilm Wako Pure Chemical Industries) and agitated at 80°C for 20 minutes. Then, each substrate sample was washed with pure water to complete the roughening treatment.

[0269] (5-3) Neutralization Treatment Each substrate sample after roughening treatment was placed in a neutralization solution at 40°C (an aqueous solution containing "Reduction Solution Securigant P" manufactured by Atotec Japan Co., Ltd. and "Sulfuric Acid" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and agitated at 40°C for 10 minutes. Then, each substrate sample was washed with pure water to complete the neutralization treatment.

[0270] (5-4) Observation of the protective layer on the substrate edge The protective layer on the edge of each substrate sample obtained in (5-3) after neutralization treatment was observed using a digital microscope (Keyence Corporation "VHX-6000"). Using the observation results, the roughening resistance of the protective layer on the edge of each substrate sample was evaluated according to the following criteria. In Comparative Example 1, no protective layer was formed and the core substrate 2 was used as is, so it is indicated with "-" in Table 5 below. [Evaluation criteria for roughening resistance on the substrate edge] "○": The protective layer remains on the entire edge of the substrate sample. "△": The protective layer remains on a part of the edge of the substrate sample. "×": The protective layer does not remain on the edge of the substrate sample.

[0271] (5-5) Observation of the protective layer at the four corners of the substrate The protective layer at the four corners of each substrate sample obtained in (5-3) above after neutralization treatment was visually observed. Using the observation results, the roughening resistance of the protective layer at the four corners of each substrate sample was evaluated according to the following criteria. [Evaluation criteria for roughening resistance at the four corners of the substrate] "○": The glass substrate (core substrate 1 or core substrate 2) is not exposed at the four corners of the substrate sample. "×": The glass substrate (core substrate 1 or core substrate 2) is exposed at the four corners of the substrate sample.

[0272] <Test Example 6: Evaluation of Plating Adhesion> For each substrate sample obtained in (5-3) above after neutralization treatment, the following steps (6-1) to (6-7) were performed in this order to form an electroless plating layer. (6-1) Alkali cleaning (Cleaning and charge adjustment of the substrate sample surface) The substrate was cleaned at 60°C for 5 minutes using "Cleaning Cleaner Securiganth 902" manufactured by Attec Japan.

[0273] (6-2) Soft etching (cleaning of the substrate sample surface) The surface of each substrate sample was treated with a sulfuric acid sodium peroxodisulfate aqueous solution at 30°C for 1 minute.

[0274] (6-3) Pre-dip (adjustment of the surface charge of the substrate sample for Pd impartment) The surface of each substrate sample was treated at 25°C for 2 minutes using "Pre. Dip Neoganth B" manufactured by Attec Japan.

[0275] (6-4) Activator application (Pd application to the surface of the substrate sample) The surface of each substrate sample was treated at 40°C for 5 minutes using "Activator Neoganth 834" manufactured by Attec Japan.

[0276] (6-5) Reduction (reduction of Pd applied to the surface of the substrate sample) The surface of each substrate sample was treated at 30°C for 5 minutes using a mixture of "Reducer Neoganth WA" and "Reducer Accelerator 810 mod." manufactured by Attec Japan.

[0277] (6-6) Electroless copper plating (deposition of Cu on the surface of the substrate sample (Pd surface)) The surface of each substrate sample was treated at 35°C using a mixed solution of Attec Japan's "Basic Solution Printganth MSK-DK", Attec Japan's "Copper Solution Printganth MSK", Attec Japan's "Stableizer Printganth MSK-DK", and Attec Japan's "Reducer Cu". This treatment was continued until the thickness of the electroless copper plating layer reached approximately 0.1 μm.

[0278] (6-7) Annealing (removal of residual hydrogen gas from the surface of the substrate sample) Each substrate sample was heated at 120°C for 30 minutes and subjected to annealing treatment.

[0279] By performing steps (6-1) to (6-7) above in this order, an electroless copper plating layer was formed on each substrate sample. The end faces of each substrate sample on which the electroless copper plating layer was formed were observed using a digital microscope (Keyence Corporation "VHX-6000"). Using the observation results, the plating adhesion at the end faces of each substrate sample was evaluated according to the following criteria. [Evaluation criteria for plating adhesion at the substrate end faces] "○": The electroless copper plating layer is uniformly formed over the entire protective layer at the end face of the substrate sample. "△": The electroless copper plating layer is formed on only a part of the protective layer at the end face of the substrate sample. "×": The electroless copper plating layer is not formed on the protective layer at the end face of the substrate sample.

[0280] The results of Test Examples 3 to 6 for the substrate samples obtained in each example and comparative example are shown in Tables 3 to 5 below. In Comparative Example 1, no protective layer was formed and the core substrate 2 was used as is, so in Table 5 below, the items "Resin Sheet No." and "Method of Forming Protective Layer" are indicated with "-". Also, in Comparative Examples 2 and 3, no resin sheet was used when forming the protective layer, so in Table 5 below, the item "Resin Sheet No." is indicated with "-".

[0281]

[0282]

[0283]

Claims

1. A method for manufacturing a substrate, comprising: (A) preparing a core substrate having a first main surface, a second main surface, and an end surface sandwiched between the first main surface and the second main surface; (B) preparing a resin sheet having a support and a resin composition layer provided on the support; and (C) covering the end surface of the core substrate with the resin composition layer of the resin sheet.

2. The manufacturing method according to claim 1, further comprising the step of (D) curing the resin composition layer after step (C).

3. The manufacturing method according to claim 2, further comprising the step of roughening the cured resin composition layer after step (D).

4. The manufacturing method according to claim 3, further comprising the step of removing the support provided on the resin sheet after step (C) and before the step of roughening the cured resin composition layer.

5. The manufacturing method according to claim 2, further comprising the step of forming a conductive layer on a cured resin composition layer after step (D).

6. The manufacturing method according to claim 1, wherein step (C) is performed by a hot roll lamination method.

7. The manufacturing method according to claim 1, wherein the resin composition layer of the resin sheet contains a thermosetting resin.

8. The manufacturing method according to claim 7, wherein the thermosetting resin includes an epoxy resin.

9. The manufacturing method according to claim 1, wherein the resin composition layer provided in the resin sheet contains an organic solvent, and the content of the organic solvent is 0.6% by mass or more and 10% by mass or less, when the total components of the resin composition layer are considered to be 100% by mass.

10. The manufacturing method according to claim 1, wherein the melt viscosity of the resin composition layer of the resin sheet at a temperature of 100°C is 500 poise or more and 10,000 poise or less.

11. The manufacturing method according to claim 1, wherein the thickness of the resin composition layer provided in the resin sheet is 5 μm or more.

12. The manufacturing method according to claim 1, wherein the length of the short axis of the resin composition layer of the resin sheet is 30 mm or less.

13. The manufacturing method according to claim 1, wherein in step (A), the core substrate is a glass substrate.

14. The manufacturing method according to claim 1, wherein in step (A), the core substrate further comprises an insulating layer on at least one of the first main surface and the second main surface.

15. The manufacturing method according to claim 1, wherein in step (A), the core substrate does not have an insulating layer on the first main surface and the second main surface.

16. The manufacturing method according to claim 15, wherein step (C) includes, in this order, a step of bonding a portion of the resin composition layer of the resin sheet to either a first main surface or a second main surface of the core substrate, and a step of covering the end surface of the core substrate with the remaining portion of the resin composition layer of the resin sheet by folding the resin sheet from the support side.

17. The manufacturing method according to claim 15, further comprising the step of forming an insulating layer on at least one of the first main surface and the second main surface of the core substrate after step (C).

18. A semiconductor device comprising a substrate manufactured by the manufacturing method described in any one of claims 1 to 17.

19. A resin sheet comprising a support and a resin composition layer provided on the support; a resin sheet for use in a method for manufacturing a substrate, comprising the steps of: preparing a core substrate having a first main surface, a second main surface, and an end surface sandwiched between the first main surface and the second main surface; and covering the end surface of the core substrate with the resin composition layer of the resin sheet.

20. The resin sheet according to claim 19, wherein the resin composition layer provided on the resin sheet contains a thermosetting resin.

21. The resin sheet according to claim 19, wherein the melt viscosity of the resin composition layer provided in the resin sheet at a temperature of 100°C is 500 poise or more and 10,000 poise or less.

22. The resin sheet according to claim 19, wherein the length of the short axis of the resin composition layer provided in the resin sheet is 30 mm or less.

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