TW202303864A - Circuit board manufacturing method - Google Patents

Abstract

Provided is a novel circuit board manufacturing method with which it is possible to form a conductor circuit with fine patterns even when an insulating layer contains an inorganic filler. The circuit board manufacturing method comprises the following steps (X), (Y), and (Z): (X) a step for forming a first conductor circuit on a metal layer of a metal layer-attached substrate; (Y) a step for forming a resin composition layer from a resin composition so as to embed the first conductor circuit formed on the metal layer, and forming an insulating layer by curing the resin composition layer; and (Z) a step for removing the metal layer-attached substrate to form a circuit board having a first main surface exposing the first conductor circuit. The resin composition includes an epoxy resin, a curing agent, and an inorganic filler.

Description

Manufacturing method of circuit board

The present invention relates to a method for manufacturing a circuit board.

In the manufacture of wafer-level packaging (WLP) or panel-level packaging (PLP) semiconductor packaging, circuit boards such as wiring boards, generally speaking, hardening resin materials are placed on wafers or panel boards to harden and form insulation After layering, a conductor layer is formed on the insulating layer, and this is formed by repeating multilayering (for example, Patent Document 1). [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Unexamined Patent Publication No. 2012-015191

[Problem to be Solved by the Invention]

As the performance of electronic devices increases, further miniaturization of wiring is required for circuit boards used in semiconductor packages. However, the conventional method of forming a conductive layer on an insulating layer has a limit to the miniaturization of wiring.

In addition, insulating layers used in circuit boards may contain inorganic fillers such as silicon dioxide in order to achieve characteristics such as low thermal expansion coefficient and low loss tangent. However, in such cases, miniaturization of wiring is difficult.

The present invention provides a novel method of manufacturing a circuit board capable of forming a conductor circuit in a fine pattern even when the insulating layer contains an inorganic filler. [Means for solving problems]

The inventors of the present application, as a result of earnest examination in order to solve the above-mentioned problems, found that the above-mentioned problems can be solved by a method of manufacturing a circuit board having the following configuration, and completed the present invention.

That is, the present invention includes the following matters. [1] A method of manufacturing a circuit board, comprising the following steps (X), (Y) and (Z): (X) the step of forming a first conductor circuit on the metal layer of the metal-coated base material, (Y) a step of forming a resin composition layer with a resin composition so as to embed the first conductor circuit formed on the metal layer, and curing the resin composition layer to form an insulating layer, (Z) The step of removing the base material with the metal layer to form a circuit substrate having the first main surface exposed by the first conductor circuit; The resin composition includes epoxy resin, hardener and inorganic filler. [2] According to the method of [1], when the non-volatile matter in the resin composition is 100% by mass, the content of the aforementioned inorganic filler in the resin composition is not less than 20% by mass and not more than 75% by mass. [3] According to the method of [1] or [2], the average particle diameter of the inorganic filler is 0.6 μm or less. [4] The method according to any one of [1] to [3], wherein the inorganic filler is silicon dioxide. [5] According to the method of any one of [1] to [4], the minimum melt viscosity of the resin composition is 5000 poise or less. [6] The method according to any one of [1] to [5], wherein the thickness of the metal layer is less than 0.5 μm. [7] According to the method of any one of [1] to [6], the arithmetic mean roughness Ra of the surface of the metal layer is 200 nm or less, and the maximum value of the height of the surface of the metal layer measured in the thickness direction of the substrate with the metal layer The TTV difference from the minimum value is 50 μm or less. [8] According to the method of any one of [1] to [7], in the substrate with a metal layer, the base material is selected from a metal base material, an inorganic base material, and an organic base material having a composition different from that of the metal layer. [9] The method according to any one of [1] to [8], step (Z) is performed by removing the metal layer after removing the substrate. [10] The method of any one of [1] to [9], step (X), including (X-1) providing a photoresist on the metal layer, exposing/developing the photoresist, exposing the metal layer corresponding to the circuit pattern of the first conductor circuit to be formed, and (X-2) A conductor layer is formed on the exposed metal layer to form a first conductor circuit. [11] The method according to any one of [1] to [10], wherein the first conductor circuit includes a trench-type conductor circuit. [12] The method according to any one of [1] to [11], step (Y), comprising taking a resin sheet comprising a support film and a resin composition layer disposed on the support film, and combining the resin composition layer and The form of the first conductor circuit bonding is laminated on the base material. [13] The method of any one of [1] to [12], after step (Y), including (i) the step of forming a second conductor circuit on the surface of the insulating layer, and (ii) A step of forming a resin composition layer so as to embed the second conductor circuit, and curing the resin composition layer to form an insulating layer. [14] According to any one of [1] to [13], the circuit board is used for semiconductor packaging. [15] A circuit substrate having a first main surface and a second main surface; Contains a trench-type conductor circuit on the first main surface, The minimum line/space ratio (L/S) of the trench conductor circuit is 2/2μm or less, In a section perpendicular to the first main surface and perpendicular to the extending direction of the trench-type conductor circuit in the direction Y, the angle difference between the direction y1 of the straight line defined by the sidewall of the trench-type conductor circuit and the direction Y is 20° or less, The insulating layer defining the first main surface together with the trench-type conductor circuit is composed of a cured product of a resin composition including an epoxy resin, a curing agent, and an inorganic filler. [16] The circuit board according to [15], the trench-type conductor circuit has an inverse conical shape whose width increases from the first main surface toward the depth direction of the circuit board. [17] For the circuit substrate as in [15] or [16], the thickness T and width W of the trench-type conductor circuit in the cross-section in the direction Y perpendicular to the first main surface and also perpendicular to the extending direction of the trench-type conductor circuit The ratio (T/W) is 1.5 or more. [18] The circuit board according to any one of [15] to [17], the exposed surface of the trench-type conductor circuit in a cross-section in the direction Y perpendicular to the first main surface and also perpendicular to the extending direction of the trench-type conductor circuit, It is 0.05W or more lower than the exposed surface of the insulating layer defining the first main surface together with the trench-type conductor circuit. [19] The circuit board according to any one of [15] to [18], which has a multilayer structure with two or more circuit layers. [20] A semiconductor package comprising the circuit board according to any one of [15] to [19], and a semiconductor chip provided on the first main surface so as to be conductively connected to the trench-type conductor circuit of the circuit board. [21] The semiconductor package as in [20] is a fan-out (Fan-Out) package. [Effect of Invention]

According to the present invention, it is possible to provide a novel method of manufacturing a circuit board in which a conductive circuit can be formed in a fine pattern even when the insulating layer contains an inorganic filler.

Before describing in detail the manufacturing method of the circuit board of the present invention, the "resin composition" used in the manufacturing method of the present invention will be described.

＜Resin composition＞ In the method of manufacturing a circuit board of the present invention, a resin composition layer is formed to embed a conductor circuit, and the resin composition layer is cured to form an insulating layer. Here, the resin composition layer is formed using a resin composition containing an epoxy resin, a curing agent, and an inorganic filler, from the viewpoint of being able to form an embedded conductor circuit and exhibit sufficient insulation after curing.

-Epoxy resin- Examples of epoxy resins include catechol epoxy resins, bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, bisphenol AF epoxy resins, Dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol novolak type epoxy resin, phenol novolak type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type cyclo Oxygen resin, naphthol type epoxy resin, onion (anthracene) type epoxy resin, glycidyl amine type epoxy resin, glycidyl ester type epoxy resin, cresol novolak type epoxy resin, biphenyl type epoxy resin Oxygen resin, linear aliphatic epoxy resin, epoxy resin with butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, spiro ring-containing epoxy resin, cyclohexane epoxy resin , Cyclohexanedimethanol type epoxy resin, naphthyl ether type epoxy resin, trimethylol type epoxy resin, tetraphenylethane type epoxy resin, etc. An epoxy resin may be used individually by 1 type, and may use it in combination of 2 or more types.

The resin composition preferably contains an epoxy resin having two or more epoxy groups in one molecule as the epoxy resin. From the viewpoint of significantly obtaining the desired effect of the present invention, the ratio of the epoxy resin having two epoxy groups in one molecule to 100% by mass of the non-volatile components of the epoxy resin is 50% by mass or more. Preferably, more than 60% by mass is more preferable, especially preferably more than 70% by mass.

Epoxy resins are classified into epoxy resins that are liquid at a temperature of 20°C (hereinafter referred to as "liquid epoxy resins"), and epoxy resins that are solid at a temperature of 20°C (hereinafter referred to as "solid epoxy resins"). shaped epoxy resin"). The resin composition, as the epoxy resin, may contain only the liquid epoxy resin, or only the solid epoxy resin. From the viewpoint of significantly obtaining the effect of the present invention, a combination of the liquid epoxy resin and the solid epoxy resin may be included. Preferable epoxy resin.

As a liquid epoxy resin, what has 2 or more epoxy groups in 1 molecule is preferable.

As the liquid epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, glycidyl ester epoxy resin, glycidyl amine type epoxy resin Oxygen resin, phenol novolac type epoxy resin, alicyclic epoxy resin with ester skeleton, cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, glycidylamine type epoxy resin, and Epoxy resins with a diene structure are preferred, and bisphenol A epoxy resins and bisphenol F epoxy resins are more preferred.

Specific examples of liquid epoxy resins include "HP4032", "HP4032D", and "HP4032SS" (naphthalene-type epoxy resins) manufactured by DIC Corporation, "828US" manufactured by Mitsubishi Chemical Corporation, "jER828EL", " 825", "Epikote 828EL" (bisphenol A type epoxy resin), "jER807" manufactured by Mitsubishi Chemical Corporation, "1750" (bisphenol F type epoxy resin), "jER152" (phenol novolac resin) manufactured by Mitsubishi Chemical Corporation Type epoxy resin), "630" and "630LSD" (glycidylamine type epoxy resin) manufactured by Mitsubishi Chemical Corporation, "ZX1059" (bisphenol A type epoxy resin and bisphenol Mixed product of F-type epoxy resin), "EX-721" (glycidyl ester type epoxy resin) manufactured by Nagase Chemtex, "Celloxide 2021P" (alicyclic epoxy resin with ester skeleton) manufactured by Daicel Corporation , "PB-3600" (epoxy resin with a butadiene structure) manufactured by Daicel Corporation, "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane type) manufactured by Nippon Steel Chemicals and Materials Co., Ltd. epoxy resin), etc. These may be used individually by 1 type, and may use it in combination of 2 or more types.

As the solid epoxy resin, a solid epoxy resin having 3 or more epoxy groups in 1 molecule is preferred, and an aromatic solid epoxy resin having 3 or more epoxy groups in 1 molecule is more preferable. good.

As the solid epoxy resin, quinone-type epoxy resin, naphthalene-type epoxy resin, naphthalene-type four-functional epoxy resin, ortho-methyl novolak-type epoxy resin, dicyclopentadiene-type epoxy resin, three Phenol type epoxy resin, naphthol type epoxy resin, bisphenol type epoxy resin, naphthalene ether type epoxy resin, onion (anthracene) type epoxy resin, bisphenol A type epoxy resin, bisphenol AF type epoxy resin Resin, tetraphenylethane type epoxy resin is preferable, quinone type epoxy resin, naphthalene type epoxy resin, naphthyl ether type epoxy resin, bisphenol AF type epoxy resin are more preferable.

Specific examples of solid epoxy resins include "HP4032H" (naphthalene-type epoxy resin), "HP-4700", "HP-4710" (naphthalene-type tetrafunctional epoxy resin) manufactured by DIC Corporation, "N-690" (o-methyl novolac epoxy resin), "N-695" (o-methyl novolac epoxy resin), "HP-7200", "HP-7200HH", "HP-7200H" ( Dicyclopentadiene type epoxy resin), "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000", "HP6000L" (Benzene ether type epoxy resin); "EPPN-502H" (triphenol epoxy resin), "NC7000L" (naphthol novolac epoxy resin), "NC3000H", "NC3000", "NC3000L" manufactured by Nippon Kayaku Co., Ltd. , "NC3100" (biphenyl type epoxy resin); "ESN475V" (naphthol novolac type epoxy resin) and "ESN485" (naphthol novolac type epoxy resin) manufactured by Nippon Steel Chemical & Materials Co., Ltd.; Mitsubishi Chemical Corporation Manufactured "YX4000H", "YL6121" (biphenyl type epoxy resin), "YX4000HK" (bixylenol type epoxy resin), "YX8800" (anthracene type epoxy resin); Osaka Gas Chemical Co., Ltd. "PG-100", "CG-500" manufactured by Mitsubishi Chemical Corporation, "YX7760" (bisphenol AF type epoxy resin), "YL7800" (fluorene type epoxy resin), "jER1010" (solid bisphenol Phenol A type epoxy resin), "jER1031S" (tetraphenylethane type epoxy resin), etc. These may be used individually by 1 type, and may use it in combination of 2 or more types.

When using a combination of liquid epoxy resin and solid epoxy resin as the epoxy resin, the ratio (liquid epoxy resin: solid epoxy resin) is preferably 1:0.1 to 1:20 by mass. More preferably, it is 1:0.3 to 1:15, and particularly preferably, it is 1:0.5 to 1:10. By making the quantity ratio of liquid epoxy resin and solid epoxy resin into such a range, the desired effect of this invention can be acquired remarkably. Furthermore, generally, when used in the form of a resin sheet, it has moderate adhesiveness. In addition, in general, when used in the form of a resin sheet, sufficient flexibility is obtained and handling properties are improved. Furthermore, usually, a cured product having sufficient breaking strength can be obtained.

The epoxy equivalent of epoxy resin is preferably 50g/eq.～5000g/eq., more preferably 50g/eq.～3000g/eq., more preferably 80g/eq.～2000g/eq., and further More preferably, it is 110g/eq.-1000g/eq. By setting it as this range, the hardened|cured material of the resin composition with sufficient bridging density can be realizable. Epoxy equivalent is the mass of epoxy resin containing 1 equivalent of epoxy group. The epoxy equivalent can be measured in accordance with Japanese Industrial Standard JIS K7236.

The weight average molecular weight (Mw) of the epoxy resin is preferably from 100 to 5000, more preferably from 250 to 3000, and still more preferably from 400 to 1500, from the viewpoint of remarkably obtaining the effect expected by the present invention. The weight average molecular weight of an epoxy resin is the weight average molecular weight of polystyrene conversion measured by the gel permeation chromatography (GPC) method.

The epoxy resin content is preferably 10% by mass when the non-volatile components in the resin composition are 100% by mass (percentage by mass) from the viewpoint of obtaining a cured product with good mechanical strength and insulation reliability. or more, more preferably at least 15% by mass, and still more preferably at least 20% by mass. The upper limit of the epoxy resin content is preferably 90% by mass or less, more preferably 85% by mass or less, particularly preferably 45% by mass or less, and 40% by mass or less from the viewpoint of remarkably obtaining the desired effect of the present invention. , or less than 35% by mass.

The content of the epoxy resin is preferably 20% by mass or more, more preferably 30% by mass or more, and even more preferably 100% by mass of the resin component in the resin composition, from the viewpoint of remarkably obtaining the effects of the present invention. Preferably it is 40 mass % or more or 50 mass % or more, More preferably, it is 90 mass % or less, More preferably, it is 85 mass % or less, More preferably, it is 80 mass % or less. In the present invention, the "resin component" of the resin composition refers to a component excluding the inorganic filler described later, among the non-volatile components constituting the resin composition.

-hardener- Examples of the curing agent include active ester-based curing agents, phenol-based curing agents, naphthol-based curing agents, benzoxazine-based curing agents, cyanate-based curing agents, carbodiimide-based curing agents, amine-based Hardener, acid anhydride hardener, etc. As the curing agent, one type may be used alone, or two or more types may be used in combination.

As the active ester hardener, a compound having one or more active ester groups in one molecule can be used. Among them, as active ester-based hardeners, phenol esters, thiophenol esters, N-hydroxylamine esters, esters of heterocyclic hydroxy compounds, etc. are used, and esters having two or more highly reactive esters in one molecule are used. Based compounds are preferred. The active ester hardener is preferably obtained by condensation reaction of carboxylic acid compound and/or thiocarboxylic acid compound with hydroxyl compound and/or mercapto compound. In particular, from the viewpoint of improving heat resistance, active ester-based hardeners obtained from carboxylic acid compounds and hydroxy compounds are preferred, and active ester-based hardeners obtained from carboxylic acid compounds and phenol compounds and/or naphthol compounds are preferred. The agent is better.

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

Examples of the phenol compound or the naphthol compound include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenol naphthalene, methylated bisphenol A, and 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, phloroglucinol, glucinol, dicyclopentadiene type Diphenol compounds, phenol novolac, etc. Here, the "dicyclopentadiene-type diphenol compound" refers to a diphenol compound obtained by condensing two molecules of phenol with one molecule of dicyclopentadiene.

Specific preferred examples of active ester hardeners include active ester hardeners containing a dicyclopentadiene-type diphenol structure, active ester hardeners containing a naphthalene structure, and acetylated compounds containing phenol novolaks. Active ester-based hardeners, active ester-based hardeners containing benzoyl compounds of phenol novolaks. Among them, active ester-based hardeners containing a naphthalene structure and active ester-based hardeners containing a dicyclopentadiene-type diphenol structure are more preferable. The term "dicyclopentadiene-type diphenol structure" means a divalent structural unit composed of phenylene-pentadiene-phenylene.

Commercially available active ester-based hardeners include active ester-based hardeners "EXB9451", "EXB9460", "EXB9460S", "HPC-8000-65T", " HPC-8000H-65TM", "EXB-8000L-65TM" (manufactured by DIC Corporation); naphthalene-type active ester hardeners containing naphthalene structure "EXB9416-70BK", "EXB-8100L-65T", "EXB-8150L- 65T", "EXB-8150-65T", "HPC-8150-60T", "HPC-8150-62T", "HPB-8151-62T" (manufactured by DIC), "PC1300-02-65T" (Air Water manufactured by the company); active ester-based hardener containing acetylated phenol novolac "DC808" (manufactured by Mitsubishi Chemical Corporation); active ester-based hardener containing benzoyl compound of phenol novolac "YLH1026" (manufactured by Mitsubishi Chemical Corporation) ; active ester hardener of acetylated phenol novolac "DC808" (manufactured by Mitsubishi Chemical Corporation); company); "EXB-8500-65T" (manufactured by DIC Corporation); etc.

The content of the active ester-based hardener is 100% by mass, preferably 1% by mass or more, more preferably 2% by mass or more, based on 100% by mass of the non-volatile components in the resin composition from the viewpoint of remarkably obtaining the effects of the present invention. , and more preferably at least 4% by mass, preferably at most 50% by mass, more preferably at most 40% by mass, and even more preferably at most 30% by mass.

The content of the active ester-based hardener is preferably at least 5 mass%, more preferably at least 10 mass%, when the resin component in the resin composition is 100 mass%, from the viewpoint of remarkably obtaining the effect of the present invention, Further more preferably, it is at least 15% by mass, more preferably at most 70% by mass, more preferably at most 60% by mass, still more preferably at most 50% by mass.

As the phenolic curing agent and the naphthol-based curing agent, those having a phenolic structure are preferable from the viewpoint of heat resistance and water resistance. In addition, from the viewpoint of adhesion to the conductor layer, nitrogen-containing phenol-based hardeners and nitrogen-containing naphthol-based hardeners are preferable, and phenol-based hardeners containing a triazine skeleton, triazine-skeleton-containing The naphthol series hardener is better.

Specific examples of phenol-based hardeners and naphthol-based hardeners include "MEH-7700", "MEH-7810", and "MEH-7851" manufactured by Meiwa Kasei Co., Ltd., "NHN-7851" manufactured by Nippon Kayaku Co., Ltd. ", "CBN", "GPH", "SN170", "SN180", "SN190", "SN475", "SN485", "SN495", "SN-495V", "SN375" manufactured by Nippon Steel Chemical and Materials Co., Ltd. ", "SN395", "TD-2090", "LA-7052", "LA-7054", "LA-1356", "LA-3018-50P", "EXB-9500" manufactured by DIC Corporation.

Specific examples of benzoxazine-based curing agents include "JBZ-OD100" (benzoxazine ring equivalent weight: 218 g/eq.), "JBZ-OP100D" (benzoxazine ring equivalent weight: 218g/eq.), "ODA-BOZ" (benzoxazine ring equivalent 218g/eq.); "P-d" (benzoxazine ring equivalent 217g/eq.) manufactured by Shikoku Chemical Industry Co., Ltd., "F-a" (benzoxazine ring equivalent 217g/eq.); Showa High Polymer Co., Ltd. "HFB2006M" (benzoxazine ring equivalent 432g/eq.), etc.

Examples of cyanate-based hardeners include bisphenol A dicyanate, polyphenol cyanate, oligosaccharide (3-methine-1,5-phenylene cyanate), 4,4 '-Methylene bis(2,6-dimethylphenyl cyanate), 4,4'-ethylene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2 -bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanatephenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1 ,3-bis(4-cyanate phenyl-1-(methylethylene))benzene, bis(4-cyanate phenyl)thioether, and bis(4-cyanate phenyl) Difunctional cyanate compounds such as ethers, polyfunctional cyanate compounds induced by phenol novolac and cresol novolac, prepolymers in which some of these cyanate compounds have been triazineized, etc. Specific examples of cyanate-based compounds include "PT30", "PT30S" and "PT60" (phenol novolac type polyfunctional cyanate), "ULL-950S" (polyfunctional Cyanate), "BA230", "BA230S75" (a prepolymer in which a part or all of bisphenol A dicyanate is triazine benzolated to form a trimer), etc.

Specific examples of carbodiimide-based curing agents include Carbodilite (registered trademark) V-03 (carbodiimide group equivalent: 216 g/eq., V-05 (carbon di Imine group equivalent weight: 216g/eq.), V-07 (carbodiimide group equivalent weight: 200g/eq.); V-09 (carbodiimide group equivalent weight: 200g/eq.); manufactured by Rhine Chemical Co. Stabaxol (registered trademark) P (carbodiimide group equivalent: 302 g/eq.).

Amine-based curing agents include resins having one or more amino groups in one molecule, such as aliphatic amines, polyether amines, alicyclic amines, aromatic amines, etc. From the viewpoint of desired effect, aromatic amines are preferable. The amine-based hardener is preferably a primary amine or a secondary amine, and more preferably a primary amine. Specific examples of amine hardeners include 4,4'-methylenebis(2,6-dimethylaniline), diphenyldiaminophen, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylene, 3,3'-diaminodiphenylene, m-phenylenediamine, m-xylylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenyl ether , 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, 2 ,2-bis(3-amino-4-hydroxyphenyl)propane, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethanediamine, 2,2-bis( 4-aminophenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis( 4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)biphenyl Oxy)phenyl)pyridine, bis(4-(3-aminophenoxy)phenyl)phenone, etc. Commercially available amine hardeners can also be used, such as "KAYABOND C-200S", "KAYABOND C-100", "KAYAHARD A-A", "KAYAHARD A-B", "KAYAHARD A-S" manufactured by Nippon Kayaku Co., Ltd., Mitsubishi Chemical Corporation Manufactured "Epicure W", etc.

Examples of the acid anhydride curing agent include compounds having one or more acid anhydride groups in one molecule. Specific examples of acid anhydride hardeners include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, Dicarboxylic anhydride, methylnaphthoic anhydride, hydrogenated methylnaphthalene anhydride, trialkyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, 5-(2,5-dioxotetrahydro-3-furyl )-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride, Naphthalene tetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenyl tetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro- 5-(tetrahydro-2,5-dioxo-3-furyl)-naphthalene[1,2-c]furan-1,3-dione, ethylene glycol bis(anhydrotriester), styrene High-molecular acid anhydrides such as styrene and maleic acid resins copolymerized with maleic acid, etc.

The content ratio of epoxy resin to hardener is based on the ratio of [the total number of epoxy groups of epoxy resin]: [the total number of reactive groups of hardener], preferably in the range of 1:0.01～1:5. 1:0.05 to 1:3 is more preferable, and 1:0.1 to 1:2 is still more preferable. Here, the "number of epoxy groups in the epoxy resin" is a value obtained by dividing the mass of the non-volatile components of the epoxy resin present in the resin composition by the epoxy equivalent. In addition, the "reactive radical number of the hardener" is a value obtained by dividing the mass of the non-volatile components of the hardener present in the hardener composition by the active radical equivalent. By setting the content ratio of the epoxy resin to the curing agent in the relevant range, a cured product having excellent flexibility can be obtained.

The content of the curing agent is 100% by mass relative to the non-volatile components in the resin composition, preferably 1% by mass or more, more preferably 3% by mass or more, and still more preferably 3% by mass or more, from the viewpoint of remarkably obtaining the effect of the present invention. It is preferably at least 5% by mass, more preferably at most 50% by mass, more preferably at most 40% by mass, further preferably at most 30% by mass.

The content of the curing agent is preferably 5% by mass or more, more preferably 10% by mass or more, and still more preferably 15 mass % or more or 20 mass % or more, Preferably it is 70 mass % or less, More preferably, it is 60 mass % or less, More preferably, it is 50 mass % or less.

-Inorganic filler- Examples of inorganic fillers include silica, alumina, aluminosilicate, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, oxide Zinc, hydrotalcite (aluminum magnesium carbonate), boehmite (boehmite), aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, boric acid Aluminum, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate, barium zirconate titanate, barium zirconate, calcium zirconate, phosphoric acid Zirconium, and zirconium phosphate tungstate, etc. Among these, calcium carbonate and silicon dioxide are suitable, and silicon dioxide is particularly suitable. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. In addition, spherical silica is preferable as silica. As the inorganic filler, one kind may be used alone, or two or more kinds may be used in combination.

Examples of commercially available inorganic fillers include "UFP-30" manufactured by Denka Corporation; "YC100C", "YA050C", "YA050C-MJE", "YA010C" manufactured by the company; "Silfill NSS-3N", "Silfill NSS-4N", "Silfill NSS-5N" manufactured by Tokuyama Corporation; manufactured by Admatex Corporation "SC2500SQ" etc.

The average particle size of the inorganic filler is preferably 0.6 μm or less for extremely fine patterns with a minimum line/space ratio (L/S) of 2/2 μm or less, and more preferably from the viewpoint of exhibiting excellent insulating properties. It is 0.5 μm or less, more preferably 0.4 μm or less, more preferably 0.01 μm or more, more preferably 0.02 μm or more, still more preferably 0.03 μm or more.

The specific surface area of the inorganic filler is preferably at least 1 m ² /g, more preferably at least 2 m ² /g, and still more preferably at least 3 m ² /g. Although the upper limit is not particularly limited, it is preferably 60 m ² /g or less, 50 m ² /g or less, or 40 m ² /g or less. The specific surface area can be calculated by the BET multi-point method using a specific surface area measuring device (Macsorb HM-1210 manufactured by MOUNTECH Co., Ltd.) to adsorb nitrogen gas on the surface of the sample according to the BET method.

Inorganic fillers are preferably treated with a surface treatment agent from the viewpoint of improving moisture resistance and dispersibility. Examples of surface treatment agents include vinyl silane coupling agents, (meth)acrylic coupling agents, fluorine-containing silane coupling agents, aminosilane coupling agents, epoxy silane coupling agents, and mercaptosilane coupling agents. , Silane-based coupling agents, alkoxysilanes, organosiloxane compounds, titanate-based coupling agents, etc. Among these, vinylsilane coupling agents, (meth)acrylic coupling agents, and aminosilane coupling agents are preferred, and aminosilane coupling agents are more preferred, from the viewpoint of remarkably obtaining the effect of the present invention. In addition, as for the surface treatment agent, one kind may be used alone, or two or more kinds may be used in combination arbitrarily.

Commercially available surface treatment agents include, for example, "KBM1003" (vinyltriethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM503" (3-methacryloxypropyl silane) manufactured by Shin-Etsu Chemical Co., Ltd. Triethoxysilane), "KBM403" (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM803" (3-mercaptopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd. silane), "KBE903" (3-aminopropyltriethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd. silane), "SZ-31" (hexamethyldisilazane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM103" (phenyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd. " KBM-4803” (long-chain epoxy silane coupling agent), “KBM-7103” (3,3,3-trifluoropropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., etc.

The degree of surface treatment by the surface treatment agent is preferably within a specified range from the viewpoint of improving the dispersibility of the inorganic filler. Specifically, for 100 parts by mass of the inorganic filler, it is better to perform surface treatment with 0.2 to 5 parts by mass of a surface treatment agent, more preferably to perform surface treatment with 0.2 to 3 parts by mass, and to use 0.3 to 5 parts by mass for surface treatment. 2 quality department to carry out surface treatment and better.

According to the degree of surface treatment of the surface treatment agent, it can be evaluated according to the amount of carbon per unit surface area of the inorganic filler. The amount of carbon per unit surface area of the inorganic filler is preferably at least 0.02 mg/m ² , more preferably at least 0.1 mg/m ² , and still more preferably at least 0.2 mg/m ² from the viewpoint of improving the dispersibility of the inorganic filler. good. On the other hand, from the viewpoint of suppressing the melt viscosity of the resin varnish and the increase of the melt viscosity in the sheet form, it is preferably 1 mg/m ² or less, more preferably 0.8 mg/m ² or less, and 0.5 mg/m ² The following is even better.

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

From the viewpoint of sufficiently reducing the coefficient of thermal expansion or loss tangent of the insulating layer, when the non-volatile components in the resin composition are 100% by mass, the content of the inorganic filler in the resin composition (thus the resin composition layer, the insulating layer The content of the inorganic filler) is preferably at least 20% by mass, more preferably at least 30% by mass, and even more preferably at least 40% by mass. As will be described later, when the insulating layer contains an inorganic filler, it is difficult to form a trench-type conductor circuit in a fine pattern. On the other hand, according to the method of the present invention, even when the content of the inorganic filler is higher, it is possible to form a trench-type conductor circuit in an extremely fine pattern. For example, the content of the inorganic filler in the resin composition may be increased to 45% by mass or more, 50% by mass or more, or 55% by mass or more. The upper limit of the content of the inorganic filler is preferably not more than 75% by mass, more preferably not more than 70% by mass, and still more preferably not more than 65% by mass.

The resin composition may further contain other components. Examples of such other components include hardening accelerators, thermoplastic resins, and other additives. Hereinafter, each component is demonstrated.

-hardening accelerator- The resin composition may further contain a curing accelerator. Examples of the hardening accelerator include phosphorus-based hardening accelerators, amine-based hardening accelerators, imidazole-based hardening accelerators, guanidine-based hardening accelerators, and metal-based hardening accelerators. The amine-based hardening accelerators, An imidazole-based hardening accelerator is preferable, and an amine-based hardening accelerator is more preferable. As the hardening accelerator, one type may be used alone, or two or more types may be used in combination.

As the phosphorus-based hardening accelerator, for example, triphenylphosphine, boric acid phosphorus compound, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, ( 4-Methylphenyl) triphenyl phosphothiocyanate, tetraphenyl phosphothiocyanate, butyl triphenyl phosphothiocyanate, etc., with triphenylphosphine, tetrabutyl phosphodecanoate better.

Examples of amine-based hardening accelerators include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethyl Aminomethyl)phenol, 1,8-diazabicyclo(5,4,0)-undecene, etc., with 4-dimethylaminopyridine, 1,8-diazabicyclo(5,4, 0)-Undecene is preferred.

Examples of imidazole-based hardening accelerators include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole , 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1 -Benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4 -Methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylbendizole, 1-cyanoethyl-2-phenylbendizole, 2 ,4-Diamine-6-[2'-methylimidazole-(1')]-ethyl-s-triazepine, 2,4-diamine-6-[2'-undecylimidazole- (1')]-ethyl-s-triazine, 2,4-diamine-6-[2'-ethyl-4'-methylimidazole-(1')]-ethyl-s- Triazine, 2,4-diamine-6-[2'-methylimidazole-(1')]-ethyl-s-triazine-isocyanuric acid add-on, 2-phenylimidazole Isocyanuric acid add-on, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5hydroxymethylimidazole, 2,3-dihydroxy-1H-pyrrolo Imidazole compounds such as [1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzyl imidazolium chloride, 2-methylimidazolium, 2-phenylimidazolium, and imidazole compounds and Adducts of epoxy resins, preferably 2-ethyl-4-methylimidazole and 1-benzyl-2-phenylimidazole.

As an imidazole type hardening accelerator, a commercial item can be used, for example, "P200-H50" by Mitsubishi Chemical Corporation etc. are mentioned.

Examples of guanidine-based hardening accelerators include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl ) Guanidine, Dimethylguanidine, Diphenylguanidine, Trimethylguanidine, Tetramethylguanidine, Pentamethylguanidine, 1,5,7-Triazabicyclo[4.4.0]dec-5-ene, 7- Methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1 -n-Octadecyl biguanide, 1,1-dimethyl biguanide, 1,1-diethyl biguanide, 1-cyclohexyl biguanide, 1-allyl biguanide, 1 -Phenyl biguanide, 1-(o-tolyl) biguanide, etc., preferably dicyandiamine and 1,5,7-triazbicyclo[4.4.0]dec-5-ene.

Examples of metal-based hardening accelerators include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include organic cobalt complexes such as cobalt (II) acetylacetonate and cobalt (III) acetylacetonate, copper (II) acetylacetonate, and copper (II) acetylacetonate. Organic copper complexes such as salt, organic zinc complexes such as zinc (II) acetylpyruvate, organic iron complexes such as iron (III) acetylpyruvate, nickel (II) acetylpyruvate, etc. Organic nickel complexes, organic manganese complexes such as manganese (II) acetylpyruvate, etc. Examples of organic metal salts include zinc octylate, tin octylate, zinc naphthenate, cobalt naphthenate, tin stearate, zinc stearate, and the like.

The content of the hardening accelerator is preferably at least 0.01% by mass, more preferably at least 0.02% by mass, especially when the non-volatile components in the resin composition are 100% by mass, from the viewpoint of remarkably obtaining the effect of the present invention. It is preferably at least 0.03% by mass, more preferably at most 3% by mass, more preferably at most 1% by mass, and most preferably at most 0.5% by mass.

The content of the hardening accelerator is preferably at least 0.01% by mass, more preferably at least 0.05% by mass, and still more preferably at least 0.05% by mass when the hardener component of the resin composition is 100% by mass from the viewpoint of remarkably obtaining the effect of the present invention. It is 0.1 mass % or more, Preferably it is 3 mass % or less, More preferably, it is 2 mass % or less, More preferably, it is 1 mass % or less.

-thermoplastic resin- The resin composition may contain a thermoplastic resin. Examples of thermoplastic resins include phenoxy resins, polyvinyl acetal resins, polyolefin resins, polyimide resins, polyamideimide resins, polyetherimide resins, polysulfone resins, and polysulfone resins. ) resin, polyether resin, polyphenylene ether resin, polyether ether ketone resin, polyester resin, etc., and phenoxy resin is preferred. A thermoplastic resin may be used individually by 1 type, or may use it in combination of 2 or more types.

The polystyrene-equivalent weight average molecular weight of the thermoplastic resin is preferably at least 38,000, more preferably at least 40,000, and still more preferably at least 42,000. The upper limit is preferably at most 100,000, more preferably at most 70,000, further preferably at most 60,000. The polystyrene equivalent weight average molecular weight of a thermoplastic resin is measured by the gel permeation chromatography (GPC) method. Specifically, for the polystyrene-equivalent weight average molecular weight of the thermoplastic resin, LC-9A/RID-6A manufactured by Shimadzu Corporation can be used as a measuring device, and Shodex K-800P/K-804L manufactured by Showa Denko Corporation can be used as a column. /K-804L, using chloroform or the like as the mobile phase, measured at a column temperature of 40°C, and calculated using the calibration curve of standard polystyrene.

Examples of phenoxy resins include bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenol acetophenone skeleton, phenolic skeleton, biphenyl skeleton, fluorenone skeleton, dicyclopentan Phenoxy resins with one or more skeletons from the group consisting of diene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, terpene skeleton, and trimethylcyclohexane skeleton . The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. The phenoxy resin may be used alone or in combination of two or more. Specific examples of phenoxy resins include "1256" and "4250" manufactured by Mitsubishi Chemical Corporation (both phenoxy resins containing a bisphenol A skeleton), "YX8100" (a phenoxy resin containing a bisphenol S skeleton), Oxygen resin), and "YX6954" (phenoxy resin containing a bisphenol acetophenone skeleton), "FX280" and "FX293" manufactured by Nippon Steel Chemical and Materials Co., Ltd., and "FX293" manufactured by Mitsubishi Chemical Corporation "YX7800BH40", "YL7500BH30", "YX6954BH30", "YX7553", "YX7553BH30", "YL7769BH30", "YL6794", "YL7213", "YL7290" and "YL7482", etc.

As the polyvinyl acetal resin, for example, polyvinyl formal resin, polyvinyl butyral resin, polyvinyl butyral resin is preferable. Specific examples of polyvinyl acetal resins include "Denka Butyral 4000-2", "Denka Butyral 5000-A", "Denka Butyral" manufactured by Denki Kagaku Kogyo Co., Ltd. 6000-C", "Electric Butyral 6000-EP", Sekisui Chemical Industry Co., Ltd.'s S Lec BH series, BX series (such as BX-5Z), KS series (such as KS-1), BL series, BM series, etc. .

Specific examples of the polyimide resin include "RICA COAT SN20" and "RICA COAT PN20" manufactured by Shin Nippon Chemical Co., Ltd. Specific examples of polyimide resins include linear polyimides obtained by reacting difunctional hydroxyl-terminated polybutadiene, diisocyanate compounds, and tetraprotic acid anhydrates (Japanese Patent Application Laid-Open No. 2006-37083 denatured polymers such as the polyimides described in the Publication No. 2002-12667 and the polyimides described in the Publication No. imide.

Specific examples of the polyamideimide resin include "Vilomax HR11NN" and "Vilomax HR16NN" manufactured by Toyobo Corporation. Specific examples of polyamide imide resins include denatured polyamides such as "KS9100" and "KS9300" (polyamide imide containing a polysiloxane skeleton) manufactured by Hitachi Chemical Industries, Ltd. imide.

Specific examples of the polyethersulfone resin include "PES5003P" manufactured by Sumitomo Chemical Co., Ltd., and the like. Specific examples of the polyphenylene ether resin include oligophenylene ether-･styrene resin "OPE-2St 1200" manufactured by Mitsubishi Gas Chemical Co., Ltd. and the like. Specific examples of the polyether ether ketone resin include "Sumiploy K" manufactured by Sumitomo Chemical Co., Ltd., and the like. Specific examples of the polyetherimide resin include "ULTEM" manufactured by GE: Inc., and the like.

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

Examples of polyolefin resins include low-density polyethylene, ultra-low-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-methyl acrylate copolymer. Copolymers; Polyolefin-based elastomers such as polypropylene and ethylene-propylene block copolymers.

Polyester resin, for example, polyethylene terephthalate resin, polyethylene naphthalate resin, polybutylene terephthalate resin, polybutylene naphthalate resin, poly Trimethylene terephthalate resin, polytrimethylene naphthalate resin, polycyclohexanedimethyl terephthalate resin, etc.

Among them, phenoxy resins and polyvinyl acetal resins are preferable as thermoplastic resins. That is, in a suitable embodiment, the resin composition contains one or more thermoplastic resins selected from the group consisting of phenoxy resins and polyvinyl acetal resins. Among them, phenoxy resins are preferable as thermoplastic resins, and phenoxy resins having a weight average molecular weight of 40,000 or more are particularly preferable.

The content of the thermoplastic resin is preferably at least 0.1% by mass, more preferably at least 0.3% by mass, and still more preferably at least 0.3% by mass when the non-volatile components in the resin composition are 100% by mass from the viewpoint of remarkably obtaining the effect of the present invention. Preferably, it is at least 0.5% by mass. The upper limit is preferably at most 5 mass %, more preferably at most 4 mass %, further preferably at most 3 mass %.

The content of the thermoplastic resin is preferably 0.5% by mass or more, more preferably 1% by mass or more, and still more preferably 1.5 mass % or more, Preferably it is 10 mass % or less, More preferably, it is 8 mass % or less, More preferably, it is 5 mass % or less.

-Other additives- The resin composition may further contain other additives. Examples of such additives include organic fillers such as rubber particles; organic metal compounds such as organic copper compounds, organic zinc compounds, and organic cobalt compounds; phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, Titanium oxide, carbon black and other coloring agents; silicone-based leveling agents, acrylic polymer-based leveling agents and other leveling agents; thickeners such as Benton and montmorillonite; polysiloxane-based defoamers, acrylic-based Defoamers, fluorine-based defoamers, polyethylene resin-based defoamers and other defoamers; urea-silane and other adhesion improvers; triazole-based adhesion imparting agents, tetrazole-based adhesion-imparting agents, triazine-based adhesion agents Adhesive imparting agents such as property imparting agents; antioxidants such as hindered phenolic antioxidants; fluorescent whitening agents such as styrene derivatives; surfactants such as fluorine-based surfactants and polysiloxane-based surfactants; Flame retardants (such as phosphate ester compounds, phosphazene compounds, phosphinic acid compounds, red phosphorus), nitrogen-based flame retardants (such as melamine sulfate), halogen-based flame retardants, inorganic flame retardants (such as antimony trioxide) Flame retardants such as phosphate ester dispersants, polyoxyalkylene dispersants, acetylene dispersants, polysiloxane dispersants, anionic dispersants, cationic dispersants and other dispersants; borate stabilizers , Titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, carboxylic anhydride-based stabilizers, and other stabilizers. These additives may be used alone or in combination of two or more. The content of such additives can also be determined according to the required properties of the insulating layer.

The preparation method of the resin composition is not particularly limited. For example, there may be mentioned a method of mixing/dispersing the compounding components and, if necessary, a solvent, etc., using a rotary mixer or the like.

The minimum melt viscosity of the resin composition (and further the resin composition layer) is preferably below 5000poise, more preferably below 4500poise, and even more preferably from the viewpoint of embedding of the conductor circuit and keeping the conductor circuit from collapsing. Below 4000poise. In addition, from the viewpoint of preventing bleeding during formation of the resin composition layer and improving processability, it is preferably at least 100 poise, more preferably at least 200 poise, and even more preferably at least 300 poise. The minimum melt viscosity of the resin composition layer can be obtained by measuring the melt viscosity by the dynamic viscoelasticity method as shown in the column of <Measurement of minimum melt viscosity> described later.

Hereinafter, the present invention will be described in detail according to suitable implementation forms. In the description, drawings may be referred to, and each drawing only schematically shows the shape, size, and arrangement of constituent elements to the extent that the invention can be understood. The present invention is not limited by the following description, and each constituent element can be appropriately changed within a range not departing from the gist of the present invention.

[Manufacturing method of circuit board] The manufacturing method of the circuit board of the present invention (hereinafter referred to as "the method of the present invention") includes the following steps (X), (Y) and (Z): (X) the step of forming a first conductor circuit on the metal layer of the metal-coated base material, (Y) a step of forming a resin composition layer with a resin composition so as to embed the first conductor circuit formed on the metal layer, and curing the resin composition layer to form an insulating layer, (Z) The step of removing the base material with the metal layer to form a circuit substrate having the first main surface exposed by the first conductor circuit; Furthermore, in the method for manufacturing a circuit board of the present invention, the resin composition includes an epoxy resin, a curing agent, and an inorganic filler.

According to the method of the present invention, in which a conductive circuit is formed on the metal layer of the base material with a metal layer, an insulating layer is formed to bury the conductive circuit, and the base material with a metal layer is removed to expose the conductive circuit, it is not necessary Etching to selectively remove the metal layer (seed layer) where the conductor circuit portion is not formed can prevent the conductor circuit from being affected by etching, and it is also advantageous because wiring (conductor circuit) can be formed in a fine pattern. In addition, the cross-sectional area of the conductor circuit is maintained, and a conductor circuit having excellent electrical characteristics can be formed. Furthermore, it is possible to form a conductor circuit with a high aspect ratio, and it is also advantageous to increase the reliability of the pad/chip bonding portion, or to increase the density by reducing the diameter of the pad. According to the method of the present invention, it is also advantageous to remove the metal layer by etching or the like to make the opening of the conductor circuit concave, and to improve the strength and reliability of the pad/wiring junction formed thereon. In this regard, in the case of forming a trench-type conductor circuit, in the conventional technique, generally speaking, the insulating layer is laser-processed to form a trench (trench), and the trench is filled with a conductor by sputtering or the like to form a trench-type conductor circuit. Such a technique has its limit in miniaturization of wiring, and especially when the insulating layer contains an inorganic filler, miniaturization of wiring is more difficult. On the other hand, according to the method of the present invention, even when the insulating layer contains an inorganic filler, it is possible to form a trench-type conductor circuit in an extremely fine pattern with a minimum line/space ratio (L/S) of 2/2 μm or less. That is, the present invention significantly contributes to miniaturization of wiring on a circuit board and higher functionality of a semiconductor package.

＜Step (X)＞ In step (X), a first conductor circuit is formed on the metal layer of the base material with a metal layer.

-Substrate with metal layer- The base material of the metal layer used in the step (X) is not particularly limited as long as it includes the base material and the metal layer provided on the base material.

In the substrate with a metal layer, the metal layer functions as a seed layer for forming a conductive circuit, and the substrate functions as a support for the metal layer. The constituent material of the substrate is not particularly limited, and any substrate selected from metal substrates, inorganic substrates, and organic substrates can be used. In a suitable embodiment, the base material is selected from a metal base material, an inorganic base material and an organic base material having a composition different from that of the metal layer.

There are no particular limitations on the metal substrate having a composition different from that of the metal layer, as long as its constituent material (metal material) is different from the composition of the metal layer. Examples of metal materials include copper, aluminum, and alloys of these and other metals (eg, tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.). The thickness of the metal substrate is not particularly limited, for example, it is in the range of not less than 0.1 mm and not more than 5 mm.

Examples of inorganic substrates include glass substrates and ceramic substrates, and examples of organic substrates include substrates made of plastic materials. The material of the glass substrate is not particularly limited. For example, various glass materials such as borosilicate glass, quartz glass, lead glass, and soda lime glass can also be used. The material of the ceramic substrate is not particularly limited, for example, various ceramic materials such as alumina and zirconia can also be used. In addition, examples of plastic materials include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polycarbonate (PC), polymethyl methacrylate, etc. Acrylic acid such as ester (PMMA), cyclic polyolefin, triacetyl cellulose (TAC), polyether ketone (PES), polyether ketone, polyimide, etc. In addition, composite materials such as fiber-reinforced plastics can also be used. The thickness of these inorganic substrates and organic substrates is not particularly limited, and can be appropriately selected according to their types, for example, it can be in the range of 0.1 mm to 5 mm.

The substrate with a metal layer includes a metal layer disposed on the substrate. The surface of the substrate on the side where such a metal layer is provided is preferably smooth and flat. The metal material constituting the metal layer is not particularly limited as long as a conductive layer can be formed on the surface of the metal layer, for example, copper, palladium, gold, platinum, silver, aluminum, and these and other metals (such as tin, Alloys of chromium, magnesium, nickel, zirconium, silicon, titanium, etc.). Formation of the metal layer on the base material can be performed, for example, by methods such as sputtering, electroless plating, and attaching an ultra-thin metal foil, and sputtering is particularly preferred.

In the base material with a metal layer, the thickness of the metal layer is preferably less than 0.5 μm or less than 0.5 μm from the viewpoint of forming a uniform concave shape at the opening of the conductor circuit after removing the metal layer by etching or the like and improving productivity. 0.3 μm, less than 0.2 μm, or less than 0.1 μm. The lower limit of the thickness of the metal layer is not particularly limited, but it is, for example, 0.01 μm or more, 0.02 μm or more, 0.03 μm or more from the viewpoint of facilitating the formation of the first conductive circuit described later.

In the present invention, the metal layer "provided on the substrate" includes not only the case where the metal layer is (directly) bonded to the substrate, but also the case where the metal layer is provided on the substrate via other layers.

Here, the other layers are not particularly limited as long as they do not hinder the effect of the present invention, for example, an adhesive layer that allows the metal layer to be provided on the substrate with good adhesion, and a layer that can peel the substrate from the metal layer. Peel off layers, etc. Such an adhesive layer and a release layer may use any conventionally known materials as long as they can exhibit desired functions. In the case of the metal layer-attached base material having a release layer between the metal layer and the base material, the base material can be peeled and removed in the step (Z) described later, and the first conductor circuit (trench type conductor circuit) can be easily formed. ) is suitable for the circuit board with the first main surface exposed. That is, in one preferred embodiment, the base material with a metal layer includes a release layer between the base material and the metal layer.

The peeling layer is not particularly limited as long as the base material can be peeled off from the metal layer, for example, an alloy layer of elements selected from the group consisting of Cr, Ni, Co, Fe, Mo, Ti, W, P; Active energy ray evaporation (sublimation) organic film etc. (WO2018/025957).

The arithmetic mean roughness Ra of the metal layer surface on which the conductive circuit is formed on the base material with a metal layer is preferably 200 nm or less, more preferably 150 nm or less, from the viewpoint that the first conductive circuit can be formed in a fine pattern , and more preferably 100 nm or less, 80 nm or less, 60 nm or less, 50 nm or less, 40 nm or less, or 20 nm or less. The lower limit of Ra is not particularly limited, and may be, for example, 1 nm or more, 2 nm or more, 3 nm or more, and the like. That is, in one embodiment, the arithmetic mean roughness Ra of the surface of the metal layer is 200 nm or less.

On the base material with metal layer, TTV (Total Thickness Variation), the difference between the maximum value and the minimum value of the height of the surface of the metal layer measured in the thickness direction of the base material with metal layer, can be formed with a fine pattern. From the viewpoint of the conductor circuit, it is preferably 50 μm or less, more preferably 40 μm or less, still more preferably 30 μm or less, 20 μm or less, 15 μm or less, 10 μm or less, 7 μm or less, or 5 μm or less. The lower limit of the TTV is not particularly limited, and may be, for example, 1 μm or more, 2 μm or more, 3 μm or more. That is, in one embodiment, the difference TTV between the maximum value and the minimum value of the height of the surface of the metal layer measured in the thickness direction of the metal layer-coated substrate is 50 μm or less.

-Formation of the first conductor circuit- In the present invention, the first conductor circuit is formed on the metal layer of the base material with a metal layer.

The formation of the first conductor circuit can be carried out according to known circuit forming methods such as the semi-additive method and the full-additive method. That is, in one implementation, step (X) includes (X-1) providing a photoresist on the metal layer, exposing/developing the photoresist to expose the metal layer corresponding to the circuit pattern of the first conductor circuit to be formed, and (X-2) A conductor layer is formed on the exposed metal layer to form a first conductor circuit.

As the photoresist, conventionally known ones that can be developed with a desired conductive circuit pattern may be used, and any of film photoresist (dry film photoresist) and liquid photoresist may be used.

Among them, the formation of the first conductor circuit is preferably carried out by the semi-additive method from the viewpoint of enjoying the effect of the present invention in which the first conductor circuit is formed in a fine pattern. Therefore, in the aforementioned (X-2), the conductive layer is preferably formed by electrolytic plating using the exposed metal layer as a plating seed layer.

In the method of the present invention, by the step (Z) described later, the base material with the metal layer is removed, so it is not necessary to remove the metal layer (seed crystal) that does not form the circuit portion by etching performed by the usual semi-additive method. layer). In the conventional technique, when such etching is performed, a part of the conductor circuit is also removed, and the cross-sectional area of the conductor circuit may not be maintained. In addition, such a problem is particularly noticeable when forming a conductive circuit with a small L/S ratio, and becomes an obstacle to forming a conductive circuit with a fine pattern. In contrast, according to the method of the present invention, a conductive circuit is formed on the metal layer of the metal-coated base material, an insulating layer is formed to embed the conductive circuit, and the metal-coated base material is removed to expose the conductive circuit. Thereby, the conductive circuit can be prevented from being affected by etching, and the first conductive circuit having a desired cross-sectional area can be formed in a fine pattern.

In the present invention, the first conductive circuit can be formed in a fine pattern. Specifically, it is possible to form a conductor circuit with a minimum line/space ratio (L/S ratio), preferably 5/5 μm or less, more preferably 3/3 μm or less, and even more preferably 2/2 μm or less. Conductor circuits having an S ratio of 1.5/1.5 μm or less or 1/1 μm or less can also be formed. That is, in one preferred embodiment, the minimum line/space ratio (L/S) of the first conductive circuit is 2/2 μm or less.

The thickness of the conductor layer forming the first conductor circuit can also be determined according to the specific design of the circuit substrate. In the present invention, fine patterns can be formed. The aspect ratio (ratio T/W of the thickness T of the conductor layer to the line width W of the conductor layer) is preferably 1.5 or more, more preferably 2 or more, 2.5 or more or 3 or more The conductor circuit.

Hereinafter, an example of step (X) will be described with reference to FIGS. 1 to 9 .

First, prepare the substrate with the metal layer (Figure 1). In FIG. 1 , as a base material of such a metal-coated layer, an example in which a metal-coated base material 10 including a base material 1 and a metal layer 2 provided on the base material is prepared is illustrated. The suitable range of the arithmetic mean roughness Ra of the surface 10a of the metal layer 2 is as mentioned above. The surface roughness of the opposite main surface 10b is not particularly limited. In addition, the suitable range of the difference TTV between the maximum value and the minimum value of the height of the surface of the metal layer measured in the thickness direction of the substrate with the metal layer is as described above.

Next, a first conductor circuit is formed on (the surface 10a of) the metal layer 2 of the metal layer-coated substrate 10 . In detail, a photoresist 20 ( FIG. 2 ) is provided on the metal layer 2 of the substrate 10 with a metal layer, and the photoresist is exposed/developed to expose the metal layer corresponding to the circuit pattern of the first conductor circuit to be formed ( image 3). Next, a conductive layer 30 is formed on the exposed metal layer to form a first conductive circuit constituted by these conductive layers 30 (FIG. 4; hereinafter, for convenience, the symbol of the first conductive circuit is also referred to as 30). According to the method of the present invention, as described above, the first conductive circuit can be formed in a fine pattern. After the first conductor circuit is formed, the photoresist 20 is removed (FIG. 5).

It is also possible to form a conductor layer interposed by a photoresist multiple times to form a desired circuit pattern or an interlayer connection pattern. For example, the second photoresist 21 (FIG. 6) is provided on the metal layer on which the first conductive circuit 30 is provided, and the photoresist is exposed/developed to expose the conductive layer 30 (first conductive circuit 30) corresponding to the interlayer connection pattern ( Figure 7). Next, a conductor layer is provided on the exposed first conductor circuit 30 to form an interlayer connection conductor (FIG. 8; the conductor layer 30 in the middle of the figure corresponds to the interlayer connection conductor). After the interlayer connection conductors are formed, the second photoresist 21 is removed (FIG. 9).

In Fig. 3 to Fig. 9, an example is shown in which the photoresist 20 is used to form the first conductor circuit, and then the photoresist 21 is used to form the interlayer connection conductor, but as long as the first conductor circuit can be formed on the metal layer, the steps are not particularly limited. . For example, to expose/develop the photoresist 20, firstly, the metal layer of the substrate is exposed corresponding to the interlayer connection pattern, and a conductive layer (interlayer connection conductor) may be formed on the exposed metal layer. In such a case, after the formation of the interlayer connecting conductor, the photoresist 20 is exposed/developed without removing the photoresist 20, and the metal layer of the base material is exposed corresponding to the circuit pattern of the first conductor circuit to be formed, and the metal layer on the exposed metal layer is exposed. A conductive layer may be formed to form a first conductive circuit.

＜Step (Y)＞ In step (Y), a resin composition layer is formed with a resin composition so as to embed the first conductor circuit formed on the metal layer, and the resin composition layer is cured to form an insulating layer.

-Resin composition layer- As mentioned above, the resin composition layer is formed by embedding the first conductor circuit and exhibiting sufficient insulation after curing, etc., using a resin containing an epoxy resin, a curing agent, and an inorganic filler. composition is formed. The resin composition is as described above in the column of <resin composition>.

Step (Y) can also be implemented by coating the aforementioned resin composition in a varnish state, or by forming a resin composition layer containing the resin composition in advance and laminating the resin composition layer.

In a suitable embodiment, the step (Y) includes laminating a resin sheet comprising a support film and a resin composition layer disposed on the support film in such a way that the resin composition layer is bonded to the first conductor circuit On the substrate on which the metallized layer of the first conductor circuit is provided.

Examples of the supporting film include films made of plastic materials, metal foils, and release paper, and films made of plastic materials and metal foils are preferred. When a film made of a plastic material is used as the support film, the plastic material includes, for example, polyesters such as PET and PEN, acrylates such as PC and PMMA, cyclic polyolefins, TAC, PES, polyetherketone, polyamide, etc. Amines etc. When a metal foil is used as the support film, examples of the metal foil include copper foil, aluminum foil, and the like, and copper foil is preferred. As the copper foil, a foil composed of a single metal of copper, or a foil composed of an alloy of copper and other metals (such as tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.) can also be used. The support film may also be subjected to matte treatment, corona treatment, and antistatic treatment on the surface that is bonded to the resin composition layer. Moreover, as a support body, the support body with a mold release layer which has a mold release layer on the surface bonded to a resin composition layer can also be used.

The resin sheet can be prepared by, for example, keeping the above-mentioned resin composition as it is, or preparing a resin varnish (varnish) in which the resin composition is dissolved in an organic solvent, and coating this on a support film using a die coater, etc., and drying it to form a resin composition. layer and prepare.

In the resin sheet, the thickness of the resin composition layer is not particularly limited as long as it can embed the first conductive circuit, and can be appropriately determined according to a specific design.

The lamination of the resin sheet is not particularly limited as long as the resin composition layer can be laminated so as to embed the first conductor circuit. substrate. As a member for thermocompression-bonding a resin sheet to a substrate with a metal layer (hereinafter also referred to as "thermocompression bonding member"), for example, a heated metal plate (SUS mirror plate, etc.) or a metal roll (SUS roll) can be mentioned. wait. In addition, instead of directly extruding the thermocompression bonding member on the resin sheet, heat-resistant rubber or the like is interposed so that the resin sheet sufficiently follows the unevenness of the surface of the substrate with the metal layer according to the first conductor circuit or the interlayer connection conductor. It is better to extrude elastic material.

Lamination of resin sheets is preferably carried out by vacuum lamination. In the vacuum lamination method, the heating and pressing temperature is preferably in the range of 60°C to 160°C, more preferably in the range of 80°C to 140°C, and the heating and pressing pressure is preferably in the range of 0.098MPa to 1.77MPa, more preferably in the range of 0.29MPa to In the range of 1.47 MPa, the heating and pressing time is preferably in the range of 20 seconds to 400 seconds, more preferably in the range of 30 seconds to 300 seconds. Lamination is preferably carried out under reduced pressure conditions with a pressure of 26.7 hPa or less. Lamination can also be performed with a vacuum laminator. Commercially available vacuum laminator, for example, can enumerate the vacuum pressing type laminator manufactured by MEIKI CO., LTD., the vacuum applicator (Vacuum Applicator) manufactured by Nikko-Materials Co., Ltd., batch vacuum Pressure applicator, etc.

After lamination, smoothing of the laminated resin sheets can also be performed under normal pressure (atmospheric pressure), for example, by pressing a thermocompression bonding member from the support film side. The extrusion conditions for the smoothing treatment may be the same conditions as the above-mentioned thermocompression bonding conditions for lamination. Lamination and smoothing can also be performed continuously using a vacuum laminator.

-Formation of insulating layer- The resin composition layer is cured to form an insulating layer. Thereby, the insulating layer is formed so as to bury the first conductive circuit.

The curing conditions of the resin composition layer are not particularly limited, and conditions generally employed when forming an insulating layer of a circuit board can be used.

The thermosetting conditions of the resin composition layer vary with the type of the resin composition. In one embodiment, the curing temperature is preferably from 120°C to 250°C, more preferably from 150°C to 240°C. The curing time is preferably from 5 minutes to 240 minutes, more preferably from 10 minutes to 150 minutes.

When forming the resin composition layer (insulation layer) using a resin sheet, the support film may be removed before curing the resin composition layer, or may be removed after curing the resin composition layer.

Hereinafter, an example of step (Y) will be described with reference to FIGS. 10 and 11 .

A resin composition layer 50 is formed to embed the first conductor circuit 30, and the resin composition layer is cured to form an insulating layer 51 (FIG. 10). In addition, the insulating layer 51 is formed thickly so as to embed the first conductor circuit or the interlayer connecting conductor, and then, the remaining insulating layer 51 is removed by polishing so that the interlayer connecting conductor is exposed, and planarization/smoothing is performed. suitable (Figure 11). The grinding method is not particularly limited, and for example, mechanical grinding methods such as chemical mechanical grinding, buff grinding, belt grinding, and roll grinding can also be used.

After the step (Y), by further performing the formation of the conductive circuit and the formation of the insulating layer, a circuit board with a multilayer structure can be manufactured.

That is, in a suitable implementation form, the method of the present invention, after step (Y), includes (i) the step of forming a second conductor circuit on the surface of the insulating layer, and (ii) A step of forming a resin composition layer so as to embed the second conductor circuit, and curing the resin composition layer to form an insulating layer.

-Step (i)- In step (i), a second conductor circuit is formed on the surface of the insulating layer.

The formation of the second conductor circuit can be carried out according to known circuit forming methods such as the semi-additive method and the full-additive method.

For example, in the case of forming the second conductor circuit by the semi-additive method, a metal layer is formed on the surface of the insulating layer, a photoresist is provided on the metal layer, and the photoresist is exposed/developed to make the metal layer corresponding to the desired circuit pattern. Part of the layer is exposed. Then, on the exposed metal layer, a conductive layer is formed by electrolytic plating, and then the photoresist is removed. Thereafter, unnecessary metal layers other than the conductor layer formation portion are removed by etching or the like, whereby a second conductor circuit having a desired circuit pattern can be formed.

When the second conductor circuit is formed by the semi-additive method, the metal layer functioning as the plating seed layer may be formed by dry plating or wet plating. Examples of dry plating include physical vapor deposition (PVD) methods such as sputtering, ion plating, and vacuum deposition, and chemical vapor deposition (CVD) methods such as thermal CVD and plasma CVD. In addition, the wet plating includes an electroless plating method. The thickness of the metal layer is, for example, 1 μm or less, 0.8 μm or less, 0.6 μm or less, 0.5 μm or less, 0.4 μm or less, or 0.2 μm or less from the viewpoint of forming a thin second conductor circuit. The lower limit of the thickness of the metal layer is, for example, 0.01 μm or more, 0.02 μm or more, etc. from the viewpoint of suppressing plating burn when the conductor layer is formed by the electrolytic plating method.

The minimum line/space ratio (L/S) of the second conductor circuit or the thickness of the circuit conductor layer can be appropriately determined according to the specific design of the circuit board.

Hereinafter, an example of step (i) will be described with reference to FIGS. 12 to 17 . Also, in the illustrated embodiment, the second conductor circuit is formed by a semi-additive method.

A metal layer 31 is formed on the surface of the insulating layer obtained in step (Y) (FIG. 12). Next, a photoresist 22 is provided on the metal layer 31 (FIG. 13), and the photoresist 22 is exposed/developed to expose the metal layer 31 corresponding to the circuit pattern of the second conductor circuit to be formed (FIG. 14). Next, on the exposed metal layer, a conductor layer 30 is formed by electrolytic plating ( FIG. 15 ), and the photoresist 22 is removed ( FIG. 16 ). Thereafter, the unnecessary metal layer 31 ( FIG. 17 ) other than the conductive layer forming portion is removed by etching or the like, so that the second conductive circuit 30 can be formed on the surface of the insulating layer.

-Step (ii)- In step (ii), a resin composition layer is formed to embed the second conductor circuit, and the resin composition layer is cured to form an insulating layer.

Step (ii) can also be implemented in the same manner as the aforementioned step (Y). The composition of the resin composition used to form the resin composition layer is as described above in the column of <Resin Composition>, and the composition of the resin sheet is as described in step (Y). In addition, the resin composition used to form the resin composition layer in step (ii) may have the same composition as the resin composition used in step (Y), or may have a different composition.

By repeatedly implementing step (i) and step (ii) N times, a circuit substrate with circuit layers of N+1 can be manufactured. When manufacturing such a multilayer structure circuit board, after performing the nth step (ii), before performing the n+1th step (i), implement the step of drilling the insulating layer and removing the insulating layer. A step of slag treatment is also possible. These steps can also be carried out according to various methods known to those skilled in the art for the manufacture of circuit boards. Thereby, in the n+1th step (i), via conductors can be formed for interlayer connection.

Hereinafter, an example of step (ii) and a procedure for forming via-hole conductors will be described with reference to FIGS. 18 to 20 .

The resin composition layer 50 is formed so as to embed the second conductive circuit 30 provided on the insulating layer 51, and the resin composition layer is cured to form the insulating layer 51 (FIG. 18). In Fig. 18, the boundary between the insulating layer 51 formed in step (Y) and the resin composition layer 50 (insulating layer 51) formed in step (ii) is indicated by a dotted line, and the insulating layer formed in step (ii) and the resin composition layer 50 (insulating layer 51) formed in step (ii) and (Y) The formed insulating layer is integrated to form the insulating layer 51 . Next, according to the desired interlayer connection pattern, the insulating layer is drilled to form a via hole 51v (via hole) ( FIG. 19 ). After the desmear process, conductor formation to the via hole 51v can form the via conductor 30 (FIG. 20).

Figures 12 to 20 show an example of performing step (i) and step (ii) once, but as previously mentioned, by repeatedly implementing step (i) and step (ii) N times, the number of circuit layers can be manufactured as N+1 circuit board.

＜Step (Z)＞ In step (Z), the base material with the metal layer is removed to form a circuit board having a first main surface where the first conductor circuit is exposed.

In step (Z), depending on the type of the metal layer or substrate used, the metal layer and the substrate can be removed simultaneously, or the metal layer can be removed after removing the substrate. Step (Z), for example, can be implemented by etching, chemical mechanical polishing and other methods. For example, after removing the base material by chemical mechanical polishing or the like, the metal layer may be removed by etching or the like. In addition, for example, when using a base material with a metal layer with a peeling layer between the metal layer and the base material, in step (Z), the base material can also be peeled off, and then the metal layer can be removed by etching, chemical mechanical polishing, etc. .

Hereinafter, an example of step (Z) will be described with reference to FIGS. 20 to 23 . In addition, in the illustrated embodiment, the procedure for removing the substrate is shown in the case of using a substrate with a metal layer having a release layer between the metal layer and the substrate.

On the substrate 10 with the metal layer, the substrate 1 is peeled off from the metal layer 2 (FIGS. 20 and 21; the peeling layer is not shown). Next, the metal layer 2 from the metal layer-attached substrate is removed by etching, chemical mechanical polishing, etc. ( FIGS. 22 and 23 ). In this way, the circuit board 100 having the first main surface 100a where the first conductive circuit 30 is exposed is formed. As shown in FIG. 23 , the circuit board 100 includes a first conductor circuit 30 as a trench-type conductor circuit on the first main surface 100 a.

According to the method of the present invention, even when the insulating layer contains an inorganic filler, it is possible to form a trench-type conductor circuit in an extremely fine pattern with a minimum line/space ratio (L/S) of 2/2 μm or less. That is, the circuit board manufactured by the method of the present invention can be suitably used as a circuit board (circuit board for semiconductor packaging) such as a redistribution board in the manufacture of a semiconductor package.

[circuit substrate] By the method of the present invention, a circuit board having a conductor circuit having an extremely fine pattern can be manufactured. The present invention also provides such a circuit board.

In one embodiment, the circuit substrate of the present invention, having a first principal surface and a second principal surface; Contains a trench-type conductor circuit on the first main surface, The minimum line/space ratio (L/S) of the trench conductor circuit is 2/2μm or less, The insulating layer defining the first main surface together with the trench-type conductor circuit is composed of a cured product of a resin composition including an epoxy resin, a curing agent, and an inorganic filler.

Hereinafter, referring to FIG. 23, the features of the circuit board of the present invention will be described.

As shown in FIG. 23 , a circuit board 100 according to an embodiment of the present invention has a first main surface 100a and a second main surface 100b, and the first main surface includes an exposed first conductor circuit 30 . The circuit board 100 also includes an insulating layer 51 that defines the first main surface 100 a together with the first conductive circuit 30 and is disposed so as to be embedded in the first conductive circuit 30 . That is, the circuit board 100 according to one embodiment of the present invention includes a trench-type conductor circuit 30 (first conductor circuit 30 ) on the first main surface 100 a. Also, in FIG. 23, the trench-type conductor circuit exposed on the first main surface extends from the front of the paper to the rear of the paper (that is, the Z direction when the paper is an X-Y plane).

In addition, in the circuit board 100 according to an embodiment of the present invention, the trench-shaped conductor circuit 30 (first conductor circuit 30 ) exposed on the first main surface 100a has an extremely fine pattern, and the minimum line/space ratio (L/S) is 2/2 μm or less, more preferably 1/1 μm or less.

In the circuit substrate 100 related to an embodiment of the present invention, the insulating layer 51 defining the first main surface 100a together with the trench-type conductor circuit 30 (first conductor circuit 30) is composed of epoxy resin, hardener and It is composed of hardened resin composition of inorganic filler. This resin composition contains an inorganic filler in the insulating layer from the viewpoint of achieving properties such as low thermal expansion coefficient and low loss tangent as described in the above-mentioned column of <Resin Composition>. As mentioned above, when the insulating layer contains an inorganic filler, it is difficult to form a trench-type conductor circuit in a fine pattern. On the other hand, according to the method of the present invention, even when the insulating layer contains an inorganic filler, and even when the content of the inorganic filler is high, it is possible to form a trench-type conductor circuit in an extremely fine pattern. The content of the inorganic filler in the insulating layer is preferably at least 20% by mass, more preferably at least 30% by mass, and still more preferably at least 40% by mass. Moreover, it is preferably at most 75 mass %, more preferably at most 70 mass %, and still more preferably at most 65 mass %. That is, in one preferred embodiment, the content of the inorganic filler in the insulating layer defining the first main surface together with the trench-type conductor circuit is 20% by mass or more. As mentioned above, the content and content of the inorganic filler were described for the insulating layer arranged to bury the trench-type conductor circuit, but as explained in the above [Method of Manufacturing Circuit Board], all the insulating layers constituting the circuit board , can have the same configuration.

In the circuit board of the present invention, the number of circuit layers (including the first conductor circuit) preferably has a multilayer structure of 2 or more. The number of circuit layers can also be determined according to the specific design of the circuit substrate, preferably more than 3, more than 4 or more than 5. The upper limit of the number of circuit layers is not particularly limited, for example, it may be 50 or less, 40 or less, 30 or less, and the like. The method of manufacturing a circuit board with a multilayer structure is as described above in [Method for Manufacturing a Circuit Board].

-Cross-section shape of trench conductor circuit- According to the method of the present invention, it is possible to form a trench-type conductor circuit with a good cross-sectional shape. Specifically, in a section in the direction Y perpendicular to the first main surface 100a and also perpendicular to the extending direction of the trench-type conductor circuit 30 (that is, the section shown in FIG. 23; the direction Y is the up-down direction in FIG. 23 ), The angle difference between the direction y1 and the direction Y of the straight line defined by the side walls of the trench-type conductor circuit 30 is 20° or less.

The angle difference between the aforementioned direction y1 and the direction Y is preferably 15° or less, more preferably 10° or less, further preferably 8° or less, 6° or less, 5° or less, 4° or less, 2° or less or 1° Hereinafter, a trench-type conductor circuit in which the angle difference is substantially 0° can also be formed.

In this regard, when a trench-type conductor circuit is provided in the conventional technique of forming a conductor circuit on an insulating layer, there is a cone that returns to the main surface (first main surface) exposed from the conductor circuit and decreases in width toward the depth direction of the circuit board. Tendency to shape conductor circuits. Such a tendency (degree of inclination angle, etc.) is more remarkable when the insulating layer contains an inorganic filler (where the content of the inorganic filler is high). In contrast, even when the insulating layer contains an inorganic filler, or even when the content of the inorganic filler is high, the circuit board manufactured by the method of the present invention can form a trench-shaped conductor with a good cross-sectional shape as described above. circuit. Also, unlike the circuit substrate manufactured by the prior art in which a conductor circuit is formed on an insulating layer, the circuit substrate manufactured by the method of the present invention has an inverse cone that returns to a width that increases from the first main surface toward the depth direction of the circuit substrate. The tendency of conductor circuits of similar shapes. That is, in one embodiment, the trench-type conductor circuit has an inverse conical shape whose width increases from the first main surface toward the depth direction of the circuit board.

-Surface characteristics of the first main surface- In the circuit substrate of the present invention, the arithmetic average roughness Ra of the first main surface is preferably 200 nm or less, more preferably 150 nm or less, further preferably 100 nm or less, 80 nm or less, 60 nm or less, 50 nm or less, 40 nm or less, or 20 nm the following. The lower limit of Ra is not particularly limited, and may be, for example, 1 nm or more, 2 nm or more, 3 nm or more, and the like. That is, in a preferred embodiment, the arithmetic average roughness Ra of the first main surface of the circuit board of the present invention is 200 nm or less.

The difference TTV between the maximum value and the minimum value of the height of the first main surface measured in the thickness direction of the circuit board is preferably 50 μm or less, more preferably 50 μm or less, from the viewpoint that the first conductive circuit can be formed in a fine pattern. 40 μm or less, more preferably 30 μm or less, 20 μm or less, 15 μm or less, 10 μm or less, 7 μm or less, or 5 μm or less. The lower limit of the TTV is not particularly limited, and may be, for example, 1 μm or more, 2 μm or more, 3 μm or more. That is, in one embodiment, the difference TTV between the maximum value and the minimum value of the height of the first main surface measured in the thickness direction of the circuit board is 50 μm or less.

In the manufacture of the semiconductor layer package, the semiconductor chip is conductively connected to the first main surface of the circuit board (specifically, the first conductor circuit (trench-type conductor circuit)). In the circuit board of the present invention, semiconductor chips can be easily and precisely connected.

-Thickness-to-Width Ratio of Trench Conductor Circuit- According to the method of the present invention, it is possible to form a trench-type conductor circuit with a high aspect ratio in a fine pattern. Specifically, the thickness T and the width of the trench-type conductor circuit in a cross-section in the direction Y perpendicular to the first main surface 100a and also perpendicular to the extending direction of the trench-type conductor circuit 30 (that is, the section shown in FIG. The W ratio (T/W) is preferably 1.5 or more, more preferably 2 or more, 2.5 or more, or 3 or more. The upper limit of the aspect ratio (T/W) is, for example, 10 or less, 8 or less, and the like. Here, the trench-type conductor circuit has an inverse conical shape as described above, and when the width W in the depth direction changes on the cross-section in the direction Y, the maximum value of the width W is used for the calculation of the aforementioned thickness-to-width ratio (T/W). .

-Shape of the opening (exposed surface) of the trench conductor circuit- According to the method of the present invention in which the substrate is removed to expose the first conductor circuit, a part of the first conductor circuit may be removed together with the substrate. For example, it is possible to remove a part of the first conductor circuit by removing the metal layer by etching or the like after the substrate is peeled off. That is to say, in one embodiment, in a cross-section (that is, the cross-section shown in FIG. The opening (exposed surface) of the opening is lower than the exposed surface of the insulating layer 51 defining the first main surface together with the trench-type conductor circuit 30 by 0.05W or more. Here, W represents the width W of the trench-type conductor circuit of the same cross-section as described above. The depression may be 0.06W or more, 0.08W or more, or 0.1W or more, and the upper limit may be, for example, 0.5W or less, 0.4W or less, or 0.3W or less.

In one embodiment, the trench-type conductor circuit has an inverse conical shape whose width increases from the first main surface toward the depth direction of the circuit board, and has a low-lying shape on the narrow first main surface side.

As described above, the circuit board of the present invention can be suitably used as a circuit board (circuit board for semiconductor packaging) such as a redistribution board in the manufacture of a semiconductor package. In the manufacture of the semiconductor layer package, the first main surface of the circuit board (specifically, the first conductor circuit (trench-type conductor circuit)) is conductively connected to the semiconductor chip. In addition, board connection terminals such as bumps are formed on the second main surface (100b in FIG. 23 ) of the circuit board.

[Semiconductor package] A semiconductor package can be manufactured using the circuit substrate of the present invention. The present invention also provides such a semiconductor package.

In one embodiment, the semiconductor package of the present invention includes the circuit substrate of the present invention, and a semiconductor chip provided on the first main surface in a manner of conductive connection with the trench-type conductor circuit (first conductor circuit) of the circuit substrate .

Referring to FIG. 24 to FIG. 26, the structure and manufacturing process of the semiconductor package of the present invention will be described.

In the semiconductor package according to an embodiment of the present invention, a semiconductor chip 110 is provided on the first main surface 100a in such a manner as to be conductively connected to the trench-type conductor circuit (first conductor circuit 30) of the circuit 100 of the present invention. Manufacture (FIG. 24; conductor circuits such as the first conductor circuit are not shown). Next, the sealing layer 120 may be provided on the first main surface 100a of the circuit board 100 so as to embed the semiconductor chip 110, and the semiconductor package 200 may be formed by singulating as appropriate (FIGS. 25 and 26). The sealing layer 120 may be formed using a conventionally known sealing material (sealing resin composition) used in the manufacture of a semiconductor package.

The semiconductor package of the present invention may also be any one of fan-in (Fan-In) package and fan-out (Fan-Out) package. In FIGS. 24 to 26 , a fan-out package having a circuit substrate 100 having a larger area than the semiconductor chip 110 is shown. When the semiconductor package of the present invention is a fan-out package, it is advantageous in combination with the original feature of the fan-out package that the rewiring layer can be formed over a large area and the conductive circuit that can be formed over a large area with fine patterns. That is, in an appropriate embodiment, the semiconductor package of the present invention is a fan-out package. [Example]

Hereinafter, the present invention will be specifically described by way of examples. The present invention is not limited by these examples. In addition, in the following, "parts" and "%" indicating amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified. The temperature and pressure conditions when no temperature is specified are room temperature (25°C) and atmospheric pressure (1atm).

<Inorganic filler used> Inorganic filler 1: For 100 parts of spherical silica ("UFP-30" manufactured by Denki Kagaku Kogyo Co., Ltd., average particle size 0.3 μm, specific surface area 30.7m ² /g), N -Phenyl-3-aminopropyl trimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM573) Part 2 surface-treated.

<Preparation Example 1> (Preparation of Resin Composition 1) Six parts of bis-xylenol-type epoxy resin ("YX4000HK" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent about 185) and naphthalene-type epoxy resin ("ESN475V" manufactured by Nippon Steel Chemical and Materials Co., Ltd., epoxy equivalent about 332) 5 parts, bisphenol AF type epoxy resin ("YX7760" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent about 238) 15 parts, naphthyl ether type epoxy resin ("HP6000L" manufactured by DIC Corporation, epoxy equivalent about 238) 213) 2 parts, cyclohexane-type epoxy resin ("ZX1658GS" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent about 135) 2 parts, phenoxy resin ("YX7500BH30" manufactured by Mitsubishi Chemical Corporation, solid content 30% by mass) Cyclohexanone: a 1:1 solution of methyl ethyl ketone (MEK), Mw=44000) 2 parts, stirred in a mixed solvent of 20 parts of solvent naphtha (solvent naphtha) and 10 parts of cyclohexanone, and heated to dissolve at the same time . After cooling to room temperature, mix it with a triazine skeleton-containing ortho-methyl phenolic hardener ("LA-3018-50P" manufactured by DIC Corporation, with a hydroxyl equivalent of about 151 and a solid content of 50% 2-methoxy propanol solution) 4 parts, active ester hardener ("EXB-8000L-65TM" manufactured by DIC Corporation, toluene solution with an active group equivalent of about 220 and a non-volatile content of 65% by mass) 12 parts, 45 parts of inorganic filler Material 1 and 0.05 parts of amine-based hardening accelerator (4-dimethylaminopyridine (DMAP)) were uniformly dispersed with a high-speed rotary mixer, and then filtered with a cartridge filter ("SHP020" manufactured by ROKITECHNO Co., Ltd.), Resin composition 1 was prepared.

<Preparation Example 2> (Preparation of Resin Composition 2) (1) Resin composition 2 was prepared in the same manner as Preparation Example 1 except that the compounding amount of inorganic filler 1 was changed from 45 parts to 65 parts.

[Example 1] (1) Manufacture of resin sheet As a support, a PET film ("Lumirror R80" manufactured by Toray, thickness 38 μm, softening point 130°C, "release PET"). Apply the resin composition 1 on the mold release agent of the support body, so that the thickness of the dried resin composition layer becomes 20 μm, apply it uniformly with a die coater, dry it from 70°C to 95°C for 4 minutes, and release it from the mold A resin composition layer is provided on the PET. Next, on the surface of the resin composition layer that is not bonded to the support, a rough surface of a polypropylene film ("ALPHAN MA-411" manufactured by Oji F-Tex Co., Ltd., thickness 15 μm) was used as a protective film to form a resin composition. Layered in a way of layer bonding. Thereby, a resin sheet having a layer composition of release PET (support body)\resin composition layer\protective film was obtained.

(2) Manufacture of circuit boards for evaluation In the following procedure, a circuit board for evaluation was fabricated.

(2-1) Preparation of substrate As a substrate, prepare a glass wafer (wafer thickness 0.8 mm, 8 inch size), and put it in an oven at 130° C. for 30 minutes to dry.

(2-2) Preparation of substrate with metal layer A metal layer is formed on the surface of the glass wafer. Specifically, a metal layer (copper layer) with a thickness of 200 nm was formed on the surface of the glass wafer using a sputtering device (“E-400S” manufactured by Canon Anelva Corporation).

(2-3) Formation of the first conductor circuit The first conductor circuit is formed according to the semi-additive method. In detail, a photoresist is provided on the metal layer of the substrate with a metal layer, exposed/developed to expose the metal layer corresponding to a comb-tooth pattern of L/S=1.5/1.5 μm (line width 1 mm). Next, copper sulfate electrolytic plating was performed, and a conductor layer (first conductor circuit) was formed with a thickness of 3 μm on the exposed metal layer, and then the photoresist was removed. Next, the following process (2-4) was performed without performing the etching (seed crystal etching) of the metal layer of the portion where the first conductor circuit was not formed. Thus, at this point in time, the conductor layer is continuous.

(2-4) Lamination of resin sheets The protective film was peeled off from the resin sheet to expose the resin composition layer. Next, using a batch-type vacuum pressure laminator (manufactured by Nikko-Materials, 2-station build-up laminator, CVP700"), the resin composition layer is laminated on the metal-attached layer so that the first conductor circuit is in contact with the resin composition layer. single side of the substrate. The implementation of this lamination is to depressurize the air pressure to below 13hPa for 30 seconds, and then crimp at 130°C and a pressure of 0.74MPa for 45 seconds. Next, hot extrusion was performed at 120° C. and a pressure of 0.5 MPa for 75 seconds for smoothing. Thereafter, the support was peeled off, and copper foil (“3EC-III” (35 μm) manufactured by Mitsui Kinzoku Co., Ltd.) was laminated on the exposed resin composition layer under the same conditions as above.

(2-5) Thermosetting of resin composition Put the laminate obtained in (2-4) above into an oven at 100°C and heat for 60 minutes, then move it into an oven at 180°C and heat for 90 minutes to thermally harden the resin composition layer. In this manner, a substrate A in which a cured product (insulating layer; thickness 20 μm) of a resin composition layer was provided on the metal layer of the base material with a metal layer so as to embed the first conductive circuit was obtained.

(2-6) Grinding of substrate The substrate A was divided into individual pieces by dicing, and polished from the substrate (glass wafer) side. The exact thickness of the polishing was not measured, but it was confirmed that the polishing did not reach the metal layer (copper layer), and a part of the glass wafer remained. This substrate is referred to as substrate B.

(2-7) Etching and removal of residual substrate Substrate B was immersed in a hydrogen fluoride aqueous solution adjusted to 5% at 25° C. for 30 minutes to completely remove the substrate (glass substrate) and obtain a substrate with the metal layer exposed. This substrate is referred to as substrate C.

(2-8) Removal of metal layer The substrate C was subjected to etching using an etching solution ("WLC-C2" manufactured by Mitsubishi Gas Chemical Co., Ltd.), and the metal layer was removed to obtain a circuit substrate in which the first conductor circuit was exposed. The obtained circuit board was used as the circuit board A for evaluation.

[Example 2] A circuit board A for evaluation was produced in the same procedure as in Example 1 except that resin composition 2 was used instead of resin composition 1.

(3) Measurement/evaluation The minimum melt viscosity of the resin compositions 1 and 2, the relative dielectric coefficient/linear thermal expansion coefficient of the cured products of the resin compositions 1 and 2, and the characteristics of the circuit board A for evaluation were measured/evaluated as follows.

＜Determination of minimum melt viscosity＞ For the resin compositions 1 and 2, the melt viscosity was measured using a dynamic viscoelasticity measuring device (“Rheosol-G3000” manufactured by UBM Co., Ltd.), and the minimum melt viscosity was obtained. Specifically, for 1 g of the sample resin composition, using a parallel plate with a diameter of 18 mm, the temperature was raised from the initial temperature of 60 °C to 200 °C at a heating rate of 5 °C/min, and the measurement conditions were measured at a temperature interval of 2.5 °C, a vibration of 1 Hz, and a strain of 1 deg. The dynamic viscoelasticity was measured, and the melt viscosity (poise) was obtained from the minimum value of the melt viscosity.

＜Measurement of Relative Permittivity＞ The resin sheets produced using the resin compositions 1 and 2 were heated at 180° C. for 90 minutes to thermoset the resin composition layer. The cured product of the obtained resin composition layer was cut into test pieces with a width of 2 mm and a length of 80 mm, and a cavity resonator dielectric coefficient measuring device ("CP521" manufactured by Kanto Applied Electronics Development Co., Ltd.) and a network analyzer ( "E8362B" manufactured by Agilent Technologies), the measurement frequency is 5.8 GHz, and the relative permittivity was measured by the cavity resonance method at 23°C. About each cured product, the measurement (n=2) of 2 test pieces was performed, and the average value was computed.

＜Measurement of Linear Thermal Expansion Coefficient＞ The resin sheets produced using the resin compositions 1 and 2 were heated at 180° C. for 90 minutes to thermoset the resin composition layer. The cured product of the obtained resin composition layer was cut into test pieces with a width of 5 mm and a length of 15 mm, and thermomechanical analysis was performed by the tensile weight method using a thermomechanical analysis device (Thermo Plus TMA8310) manufactured by Rigaku Co., Ltd. After installing the test piece in the aforementioned device, the measurement conditions were 1 g of load and 5° C./min of temperature increase rate, and were continuously measured twice. Calculate the average linear thermal expansion coefficient (ppm/°C) from 25°C to 150°C in the second measurement.

<Characteristic evaluation of circuit board A for evaluation> (1) Evaluation of embedding The evaluation circuit board A was observed from the first conductor circuit side using a non-contact interference microscope (WYKO). Next, the embedding properties were evaluated with the following criteria. Evaluation Benchmark: ×: There is a depression caused by a resin defect between the wirings, and poor embedding is observed ○: The aforementioned poor embedding was not observed

(2) Evaluation of Insulation Properties An insulation reliability test was carried out on the circuit board A for evaluation. Specifically, using a HAST tester ("PM422" manufactured by Kusumoto Chemical Co., Ltd.), a voltage of 3.3 V (bHAST) was applied to both ends of the electrodes in an environment with a temperature of 130° C. and a humidity of 85%. After 200 hours, the circuit board A for evaluation was taken out, and its resistance value was measured with a resistance measuring machine ("ECM-100" manufactured by J-RAS Corporation). Next, insulation was evaluated on the following criteria. Evaluation criteria: ×: The resistance value is less than 10 ⁸ Ω ○: The resistance value is 10 ⁸ Ω or more

In either of Examples 1 and 2, the conductive circuit was formed in a fine pattern of L/S=1.5/1.5 μm (line width: 1 mm). In addition, in Examples 1 and 2, it was confirmed that the formed insulating layer (cured product of the resin composition) was excellent in relative permittivity, linear thermal expansion coefficient, and insulation, and also excellent in embedding property of conductor circuits.

1: Substrate 2: metal layer 10: Base material with metal layer 10a: metal layer (first main surface) 10b: The second main surface 20,21,22: photoresist 30: Conductor layer (conductor circuit) 31: metal layer (plating seed layer) 50: Resin composition layer 51: Insulation layer 51v: through hole 100: circuit substrate 100a: the first main surface of the circuit substrate 100b: The second main surface of the circuit substrate 110: Semiconductor wafer 120: sealing layer 200: Semiconductor packaging

[FIG. 1] It is a schematic diagram (1) for explaining the manufacturing method of the circuit board of one embodiment of the present invention (hereinafter referred to as "the manufacturing method of the circuit board"). [Fig. 2] is a schematic diagram (2) for explaining the manufacturing method of the circuit board. [Fig. 3] is a schematic diagram (3) for explaining the manufacturing method of the circuit board. [Fig. 4] is a schematic diagram (4) for explaining the manufacturing method of the circuit board. [FIG. 5] It is a schematic diagram (5) for explaining the manufacturing method of the circuit board. [FIG. 6] It is a schematic diagram (6) for explaining the manufacturing method of the circuit board. [FIG. 7] It is a schematic diagram (7) for explaining the manufacturing method of a circuit board. [FIG. 8] It is a schematic diagram (8) for explaining the manufacturing method of the circuit board. [FIG. 9] It is a schematic diagram (9) for explaining the manufacturing method of the circuit board. [Fig. 10] is a schematic diagram (10) for explaining the manufacturing method of the circuit board. [FIG. 11] It is a schematic diagram (11) for explaining the manufacturing method of the circuit board. [FIG. 12] It is a schematic diagram (12) for explaining the manufacturing method of the circuit board. [Fig. 13] is a schematic diagram (13) for explaining the manufacturing method of the circuit board. [FIG. 14] It is a schematic diagram (14) for explaining the manufacturing method of the circuit board. [Fig. 15] is a schematic diagram (15) for explaining the manufacturing method of the circuit board. [FIG. 16] It is a schematic diagram (16) for explaining the manufacturing method of the circuit board. [FIG. 17] It is a schematic diagram (17) for explaining the manufacturing method of the circuit board. [FIG. 18] It is a schematic diagram (18) for explaining the manufacturing method of the circuit board. [FIG. 19] It is a schematic diagram (19) for explaining the manufacturing method of the circuit board. [Fig. 20] is a schematic diagram (20) for explaining the manufacturing method of the circuit board. [FIG. 21] It is a schematic diagram (21) for explaining the manufacturing method of the circuit board. [FIG. 22] It is a schematic diagram (22) for explaining the manufacturing method of the circuit board. [FIG. 23] It is a schematic diagram (23) for explaining the manufacturing method of the circuit board. In addition, FIG. 23 is a schematic diagram of a circuit board of an embodiment of the present invention. [ Fig. 24 ] is a schematic diagram (1) for explaining a semiconductor package related to an embodiment of the present invention. [ Fig. 25 ] is a schematic diagram (2) for explaining a semiconductor package related to an embodiment of the present invention. [ Fig. 26 ] is a schematic diagram (3) for explaining a semiconductor package related to an embodiment of the present invention.

Claims (21)

A method of manufacturing a circuit substrate, comprising the following steps (X), (Y) and (Z): (X) the step of forming a first conductor circuit on the metal layer of the metal-coated base material, (Y) a step of forming a resin composition layer with a resin composition so as to embed the first conductor circuit formed on the metal layer, and curing the resin composition layer to form an insulating layer, (Z) The step of removing the base material with the metal layer to form a circuit substrate having the first main surface exposed by the first conductor circuit; The resin composition includes epoxy resin, hardener and inorganic filler. The method according to claim 1, wherein when the non-volatile content in the resin composition is 100% by mass, the content of the inorganic filler in the resin composition is not less than 20% by mass and not more than 75% by mass. The method according to claim 1, wherein the average particle diameter of the aforementioned inorganic filler is 0.6 μm or less. The method according to claim 1, wherein the aforementioned inorganic filler is silicon dioxide. The method according to claim 1, wherein the minimum melt viscosity of the aforementioned resin composition is below 5000 poise. The method according to claim 1, wherein the thickness of the aforementioned metal layer is less than 0.5 μm. The method according to claim 1, wherein the arithmetic average roughness Ra of the surface of the metal layer is 200 nm or less, and the difference TTV between the maximum value and the minimum value of the height of the metal layer surface measured in the thickness direction of the substrate with the metal layer is 50 μm the following. The method of claim 1, wherein in the substrate with a metal layer, the base material is selected from a metal base material, an inorganic base material, and an organic base material having a composition different from that of the metal layer. The method according to claim 1, wherein the aforementioned step (Z) is performed by removing the aforementioned metal layer after removing the base material. The method of claim 1, wherein the aforementioned step (X) includes (X-1) providing a photoresist on the metal layer, exposing/developing the photoresist to expose the metal layer corresponding to the circuit pattern of the first conductor circuit to be formed, and (X-2) A conductor layer is formed on the exposed metal layer to form a first conductor circuit. The method according to claim 1, wherein the first conductor circuit includes a trench-type conductor circuit. The method according to claim 1, wherein the aforementioned step (Y) includes a resin sheet comprising a support film and a resin composition layer disposed on the support film, in such a manner that the resin composition layer is bonded to the first conductor circuit, layered on the substrate. The method according to claim 1, wherein after the aforementioned step (Y), comprising (i) the step of forming a second conductor circuit on the surface of the insulating layer, and (ii) A step of forming a resin composition layer so as to embed the second conductor circuit, and curing the resin composition layer to form an insulating layer. The method according to claim 1, wherein the aforementioned circuit substrate is used for semiconductor packaging. A circuit substrate having a first main surface and a second main surface; Contains a trench-type conductor circuit on the first main surface, The minimum line/space ratio (L/S) of the aforementioned trench-type conductor circuit is 2/2 μm or less, In a section perpendicular to the first main surface and perpendicular to the extending direction of the trench-type conductor circuit in the direction Y, the angle difference between the direction y1 of the straight line defined by the sidewall of the trench-type conductor circuit and the direction Y is 20° or less, The insulating layer defining the first main surface together with the trench-type conductor circuit is composed of a cured product of a resin composition including an epoxy resin, a curing agent, and an inorganic filler. The circuit substrate according to claim 15, wherein the trench-type conductor circuit has an inverse conical shape whose width increases from the first main surface toward the depth direction of the circuit substrate. The circuit substrate of claim 15, wherein the ratio of the thickness T of the trench-type conductor circuit to the width W (T/ W) is 1.5 or more. The circuit substrate according to claim 15, wherein the cross-section in the direction Y which is perpendicular to the first main surface and also perpendicular to the extending direction of the trench-type conductor circuit, the exposed surface of the trench-type conductor circuit is drawn together with the trench-type conductor circuit The exposed surface of the insulating layer on the first main surface is lowered by 0.05W or more. The circuit substrate according to claim 15, which has a multilayer structure with two or more circuit layers. A semiconductor package, comprising the circuit substrate according to any one of claims 15 to 19, and a semiconductor chip provided on the first main surface in such a manner as to be conductively connected to the trench-type conductor circuit of the circuit substrate. Such as the semiconductor package of claim 20, which is a fan-out (Fan-Out) package.

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