Printed wiring board manufacturing method

Abstract

[Problem] To provide a printed wiring board manufacturing method with which it is possible to further enhance adhesion between an insulating layer and wiring. [Solution] A metal foil 12 of which the surface has been roughened is laminated onto an insulating layer 11, heated, and subjected to pressure to form a laminate 13. Then the metal foil 12 is removed using an etching liquid, thereby exposing a roughened surface of the insulating layer 11. In the exposed roughened surface of the insulating layer 11, the quantity of metal elements included in group 3 through group 12, excluding a metal of the same type as the metal foil, as measured using X-ray photoelectron spectroscopy is at least 5 at.% relative to the total quantity of elements measured using X-ray photoelectron spectroscopy. Next, an electroless plating layer 16 is formed on the roughened surface of the insulating layer 11, a resist pattern is formed, and an electroplating layer is formed, after which the resist pattern is peeled off and a section of the electroless plating layer 16 which is exposed is removed using etching, thereby forming a wiring pattern.

Description

Printed wiring board manufacturing method

[0001] The present invention relates to a method for manufacturing a printed wiring board using a laminate in which a metal foil having a surface roughened is laminated on at least one surface of an insulating layer.

[0002] In recent years, printed wiring boards, which are widely used in electronic devices, communication devices, personal computers, and the like, have become increasingly dense, highly integrated, and lighter and thinner. Conventionally, a method for forming circuits on printed wiring boards has been known, for example, through the semi-additive process. In the semi-additive process, for example, the surface of an insulating layer is roughened by resin etching such as desmearing, and then the roughened surface is subjected to electroless plating to form a seed layer. A resist pattern is then formed thereon corresponding to non-circuit areas, and a circuit is formed by plating. This semi-additive process is suitable for forming fine circuits.

[0003] Recently, instead of roughening the surface of an insulating layer by resin etching such as desmearing, a method has been proposed in which a roughened metal foil is laminated on the surface of the insulating layer and the roughened shape of the metal foil is transferred to the insulating layer to roughen it (see, for example, Patent Document 1). This method does not require optimization of the conditions for roughening the insulating layer by desmearing or the like, and can easily roughen the insulating layer, while also forming a roughened surface with higher adhesion than when roughening by desmearing or the like.

[0004] International Publication WO2022 / 039062

[0005] However, in order to cope with the trend toward higher density and higher precision of printed wiring boards, there is a demand for further improvement in the adhesion between the insulating layer and the wiring.

[0006] The present invention has been made in view of the above problems, and has as its object to provide a method for manufacturing a printed wiring board that can further improve the adhesion between an insulating layer and wiring.

[0007] The present invention is as follows: [1] A laminate forming process includes a laminate forming step of laminating a metal foil whose surface has been roughened on at least one surface of an insulating layer, and applying heat and pressure to form a laminate, an insulating layer exposing step of removing the metal foil from the laminate using an etching solution to expose the roughened surface of the insulating layer roughened by the metal foil, an electroless plating step of performing electroless plating on the roughened surface of the insulating layer to form an electroless plated layer, a photoresist film laminating step of laminating a photoresist film on the surface of the electroless plated layer, a resist pattern forming step of exposing and developing the photoresist film to form a resist pattern, an electrolytic plating step of performing electrolytic plating on the electroless plated layer through the resist pattern to form an electrolytic plated layer, a resist pattern stripping step of stripping the resist pattern, and a wiring pattern forming step of etching away the portion of the electroless plated layer exposed by stripping the resist pattern to form a wiring pattern, A method for manufacturing a printed wiring board, wherein the amount of metal elements included in Groups 3 to 12 of the insulating layer other than the same metal as the metal foil, measured by X-ray photoelectron spectroscopy, on the roughened surface of the insulating layer exposed in the insulating layer exposing step, is 5 atomic % or more relative to the total amount of elements measured by X-ray photoelectron spectroscopy. [2] The method for manufacturing a printed wiring board according to [1], wherein the metal elements include at least one selected from the group consisting of chromium (Cr), cobalt (Co), nickel (Ni), zinc (Zn), and molybdenum (Mo). [3] The method for manufacturing a printed wiring board according to [1], wherein the insulating layer includes at least one thermosetting compound selected from the group consisting of polyphenylene ether compounds, maleimide compounds, epoxy compounds, cyanate ester compounds, and phenol compounds. [4] The method for manufacturing a printed wiring board according to [1], wherein the laminate forming step comprises: a curing step in which the insulating layer is made of a material containing a thermosetting compound, the insulating layer and the metal foil are arranged in this order on an inner layer substrate on which an inner layer circuit is formed, and heat and pressure are applied to harden the insulating layer; and a blind hole forming step in which blind holes are formed from the metal foil to reach the inner layer circuit.[5] The method for manufacturing a printed wiring board according to [1], wherein the laminate forming step includes a curing step of forming the insulating layer from a prepreg in which a base material is impregnated with or coated with a thermosetting resin composition, or a resin sheet, laminating the metal foil on at least one surface of the insulating layer, and applying heat and pressure to cure the insulating layer; and a through hole forming step of forming through holes that penetrate the insulating layer and the metal foil.

[0008] According to the present invention, the amount of metal elements contained in Groups 3 to 12 other than the same metal as the metal foil, as measured by X-ray photoelectron spectroscopy, on the roughened surface of the insulating layer exposed in the insulating layer exposing step, is 5 atomic % or more relative to the total amount of elements as measured by X-ray photoelectron spectroscopy, thereby increasing the adhesion between the insulating layer and the wiring and improving the formability of a fine wiring pattern.

[0009] In particular, if the metal element contains at least one selected from the group consisting of chromium, cobalt, nickel, zinc, and molybdenum, a higher effect can be obtained.

[0010] 1 is a diagram showing each step of a method for manufacturing a printed wiring board according to a first embodiment of the present invention; FIG. 2 is a diagram showing each step following FIG. 1; FIG. 3 is a diagram showing each step of a method for manufacturing a printed wiring board according to a second embodiment of the present invention; and FIG. 4 is a diagram showing each step following FIG.

[0011] Hereinafter, a detailed description of an embodiment of the present invention (hereinafter referred to as the "present embodiment") will be given. However, the present invention is not limited thereto, and various modifications are possible without departing from the spirit of the present invention. In this specification, the term "to" is used to mean that the numerical values ​​before and after the term are included as lower and upper limits. In the description of a group (atomic group) in this specification, a notation that does not specify substituted or unsubstituted encompasses both a group (atomic group) that has no substituent and a group (atomic group) that has a substituent. For example, the term "alkyl group" encompasses not only an alkyl group that has no substituent (unsubstituted alkyl group) but also an alkyl group that has a substituent (substituted alkyl group). In this specification, when a notation that does not specify substituted or unsubstituted is used, unsubstituted is preferred. In this specification, unless otherwise specified, the term "resin solid content" refers to the components of a thermosetting resin composition excluding fillers (including inorganic fillers) and solvents, and 100 parts by mass of resin solid content refers to 100 parts by mass of the total amount of resin components in a thermosetting resin composition excluding fillers and solvents.

[0012] 1 and 2 illustrate the steps of a method for manufacturing a printed wiring board according to a first embodiment of the present invention. <Laminate Forming Process / Curing Process> First, for example, a metal foil 12 having a roughened surface is laminated on at least one side of an insulating layer 11, followed by heating and pressure to form a laminate 13 (laminate forming process). Specifically, as shown in FIG. 1A , the laminate forming process includes a curing process in which the insulating layer 11 is made of a material containing a thermosetting compound, the insulating layer 11 and the metal foil 12 are placed in this order on an inner layer substrate 14 having an insulating substrate 14A and an inner layer circuit 14B formed thereon, and the insulating layer 11 is cured by heating and pressure. The insulating layer 11 and the metal foil 12 may be laminated on both sides of the inner layer substrate 14, or on only one side.

[0013] The inner layer substrate 14 can be manufactured by a conventionally known method. To explain an example of the manufacturing process for the inner layer substrate 14, first, through holes (not shown) are formed in an insulating substrate 14A made of a resin substrate such as a glass epoxy or polyimide resin, and then electrolytic copper plating is performed on both the top and bottom surfaces of the insulating substrate 14A and the inner surfaces of the through holes using electroless copper plating as a base. Next, a resist pattern is formed on the surface, and a conductor pattern and through-hole conductors are formed as the inner layer circuit 14B by etching, and the cavities in the through-hole conductors are filled with a filling resin such as epoxy to flatten the surface.

[0014] Before laminating the insulating layer 11 and the metal foil 12 on the inner layer substrate 14, it is preferable to roughen the surface of the inner layer substrate 14, specifically the surface of the inner layer circuit 14B, for example, by etching or the like.

[0015] [Insulating Layer 11] The insulating layer 11 can be formed, for example, from an insulating prepreg or resin sheet containing a thermosetting compound. Examples of prepregs include those obtained by impregnating or coating a substrate, such as a fibrous reinforcing material such as glass cloth or carbon fiber, with a thermosetting resin composition containing a thermosetting compound mixed with additives such as a curing agent and a coloring agent, and then semi-curing the prepreg. Examples of resin sheets include those obtained by semi-curing a thermosetting resin composition containing a thermosetting compound mixed with additives such as a curing agent and a coloring agent. The prepreg or resin sheet constituting the insulating layer 11 is cured by heating in the curing process described below.

[0016] Examples of thermosetting compounds used in the prepreg or resin sheet include polyphenylene ether compounds, maleimide compounds, epoxy compounds, cyanate ester compounds, phenol compounds, polyimide resins, benzoxazine compounds, organic group-modified silicone compounds, and compounds having a polymerizable unsaturated group. Among these, it is preferable that the insulating layer 11 contains at least one thermosetting compound selected from the group consisting of polyphenylene ether compounds, maleimide compounds, epoxy compounds, cyanate ester compounds, and phenol compounds.

[0017] (Polyphenylene ether compound) The polyphenylene ether compound is not particularly limited, but is preferably, for example, a polymer containing a repeating unit represented by the following formula (1). By containing such a polyphenylene ether compound, excellent low dielectric constant and low dielectric loss tangent can be obtained, and a uniform cured product tends to be obtained. Furthermore, the polyphenylene ether compound may further contain at least one of a repeating unit represented by the following formula (2) and a repeating unit represented by the following formula (3).

[0018] (In formula (1), R １ , R ２ , R ３ , and R ４ each independently represents an alkyl group having 6 or less carbon atoms, an aryl group, a halogen atom, or a hydrogen atom.

[0019] (In formula (2), R ５ , R ６ , R ７ , R １１ , and R １２ each independently represents an alkyl group having 6 or less carbon atoms or a phenyl group, and R ８ , R ９ , and R １０ each independently represents a hydrogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group.

[0020] (In formula (3), R １３ , R １４ , R １５ , R １６ , R １７ , R １８ , R １９ , and R ２０ each independently represents a hydrogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group, and A represents a linear, branched, or cyclic divalent hydrocarbon group having 20 or less carbon atoms.

[0021] Furthermore, the polyphenylene ether compound may have a substituent. The substituent is not particularly limited, but examples thereof include ethylenically unsaturated groups such as vinylbenzyl groups, epoxy groups, amino groups, hydroxyl groups, mercapto groups, carboxyl groups, and silyl groups. Among these, ethylenically unsaturated groups are preferred. A polyphenylene ether compound having such a substituent is also referred to as a "modified polyphenylene ether" hereinafter.

[0022] The ethylenically unsaturated group is not particularly limited, and examples thereof include alkenyl groups such as ethenyl, allyl, methallyl, propenyl, butenyl, hexenyl, and octenyl; cycloalkenyl groups such as cyclopentenyl and cyclohexenyl; and alkenylaryl groups such as vinylbenzyl and vinylnaphthyl. Among these, the vinylbenzyl group is preferred from the viewpoints of electrical properties and low water absorption.

[0023] The position of the substituent is not particularly limited, but may be, for example, both ends of the polyphenylene ether chain, one end of the polyphenylene ether chain, a side chain of the polyphenylene ether chain, or a combination thereof.Among these, from the viewpoint of heat resistance, a polyphenylene ether compound having an ethylenically unsaturated group at both ends is preferred.When the polyphenylene ether compound has two or more substituents, the respective substituents may be the same or different.

[0024] Among the above-mentioned modified polyphenylene ethers, modified polyphenylene ethers having ethylenically unsaturated groups at both ends are preferred. Such modified polyphenylene ethers are not particularly limited, but examples thereof include compounds represented by the following formula (4). By using such modified polyphenylene ethers, heat resistance and low water absorption tend to be further improved.

[0025] (In formula (4), X represents a group represented by the following formula (5) or (6), each Y independently represents a group represented by the following formula (7), and a and b represent integers of 0 to 100, with at least one being 1 or greater.) (In formula (5), R２１ , R ２２ , R ２３ , R ２７ , and R ２８ each independently represents an alkyl group having 6 or less carbon atoms or a phenyl group, and R ２４ , R ２５ , R ２６ each independently represents a hydrogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group. (In formula (6), R ２９ , R ３０ , R ３１ , R ３２ , R ３３ , R ３４ , R ３５ , and R ３６ each independently represents a hydrogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group, and A represents a linear, branched, or cyclic divalent hydrocarbon group having 20 or less carbon atoms. (In formula (7), R ３９ and R ４０ each independently represents an alkyl group having 6 or less carbon atoms or a phenyl group, and R ３７ and R ３８ each independently represents a hydrogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group.

[0026] In formula (6), the divalent hydrocarbon group represented by A is not particularly limited, but examples thereof include methylene, ethylidene, 1-methylethylidene, 1,1-propylidene, 1,4-phenylenebis(1-methylethylidene), 1,3-phenylenebis(1-methylethylidene), cyclohexylidene, phenylmethylene, naphthylmethylene, and 1-phenylethylidene.

[0027] The compound represented by formula (4) may contain one type or two or more types of groups represented by formula (7). When the compound contains two or more types of groups represented by formula (7), different types of groups represented by formula (7) may be arranged randomly, or the same type of groups represented by formula (7) may be arranged in a block pattern.

[0028] Among the modified polyphenylene ethers represented by formula (4), R ２１ , R ２２ , R２３ , R ２７ , R ２８ , R ３９ , R ４０ is an alkyl group having 3 or less carbon atoms, and R ２４ , R ２５ , R ２６ , R ２９ , R ３０ , R ３１ , R ３２ , R ３３ , R ３４ , R ３５ , R ３６ , R ３７ , R ３８ is a hydrogen atom or an alkyl group having 3 or less carbon atoms, and particularly, a modified polyphenylene ether in which X represented by the above formula (5) or (6) is a group represented by the following formula (8), (9), or (10), and Y represented by the above formula (7) is the following formula (11) or (12), or a structure in which formulas (11) and (12) are randomly arranged is more preferred.

[0029] (In the above formula (9), R ３１ , R ３２ , R ３３ , R ３４ are each independently a hydrogen atom or a methyl group; -A- is a linear, branched, or cyclic divalent hydrocarbon group having 20 or less carbon atoms. (In the above formula (10), A is a linear, branched, or cyclic divalent hydrocarbon group having 20 or less carbon atoms.)

[0030] The method for producing a modified polyphenylene ether having a structure represented by the above formula (4) is not particularly limited, but examples thereof include a method in which a bifunctional phenol compound and a monofunctional phenol compound are subjected to oxidative coupling to obtain a bifunctional phenylene ether oligomer, and the terminal phenolic hydroxyl groups of the obtained bifunctional phenylene ether oligomer are converted to vinylbenzyl ethers.

[0031] In addition, the method for producing other modified polyphenylene ethers is not particularly limited. For example, a method for producing a modified polyphenylene ether modified with a vinylbenzyl group can be exemplified by a method in which a bifunctional phenylene ether oligomer and vinylbenzyl chloride are dissolved in a solvent, and a base is added under heating and stirring to cause a reaction. In addition, a method for producing a modified polyphenylene ether modified with a carboxyl group can be exemplified by a method in which an unsaturated carboxylic acid or a functional derivative thereof is melt-kneaded with a polyphenylene ether in the presence or absence of a radical initiator to cause a reaction; or a method in which a modified polyphenylene ether modified with a carboxyl group is dissolved in an organic solvent with at least one of an unsaturated carboxylic acid and a functional derivative thereof in the presence or absence of a radical initiator to cause a reaction in the solution.

[0032] The number average molecular weight of the polyphenylene ether compound, calculated as polystyrene by a GPC method, is 500 to 5,000, preferably 700 to 3,500, and more preferably 900 to 2,500. When the number average molecular weight of the polyphenylene ether compound is 500 or more, the compound is less likely to be sticky when formed into a coating film. Furthermore, when the number average molecular weight of the polyphenylene ether compound is 5,000 or less, a decrease in solubility in solvents can be prevented.

[0033] The content of the polyphenylene ether compound is preferably 1 part by mass or more and 60 parts by mass or less, more preferably 5 parts by mass or more and 50 parts by mass or less, and even more preferably 10 parts by mass or more and 40 parts by mass or less, relative to 100 parts by mass of the resin solid content. Only one type of polyphenylene ether compound may be used, or two or more types may be used. When two or more types are used, it is preferable that the total amount is within the above range.

[0034] The vinyl group equivalent (g / eq.) of the polyphenylene ether compound is preferably 250 to 2600 g / eq., more preferably 350 to 1800 g / eq., and even more preferably 450 to 1400 g / eq. When the vinyl group equivalent (g / eq.) of the polyphenylene ether compound is within the above range, heat resistance and low water absorbency tend to be further improved.

[0035] (Maleimide Compound) The maleimide compound is not particularly limited as long as it has one or more maleimide groups in the molecule. Specific examples include N-phenylmaleimide, N-hydroxyphenylmaleimide, bis(4-maleimidophenyl)methane, 2,2-bis{4-(4-maleimidophenoxy)-phenyl}propane, bis(3,5-dimethyl-4-maleimidophenyl)methane, bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, bis(3,5-diethyl-4-maleimidophenyl)methane, maleimide compounds represented by the following formula (13), prepolymers of these maleimide compounds, or prepolymers of maleimide compounds and amine compounds. Among these, at least one selected from the group consisting of 2,2'-bis{4-(4-maleimidophenoxy)-phenyl}propane, bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, and the maleimide compound represented by the following formula (13) is preferred. By including such a maleimide compound, the resulting cured product tends to have a better balance of physical properties. From the same viewpoint, it is more preferable that the maleimide compound includes at least one selected from the group consisting of maleimide compounds represented by the following formula (13):

[0036] (In formula (13), R ６ Each independently represents a hydrogen atom or a methyl group, and preferably represents a hydrogen atom. ３ represents an integer of 1 or more, preferably an integer of 10 or less, and more preferably an integer of 7 or less.

[0037] The content of the maleimide compound can be appropriately set depending on the desired properties and is not particularly limited. From the viewpoint of further improving the balance of physical properties such as electrical properties, heat resistance, and thermal conductivity, the content is preferably 1 part by mass or more and 50 parts by mass or less, more preferably 5 parts by mass or more and 30 parts by mass or less, and even more preferably 10 parts by mass or more and 25 parts by mass or less, relative to 100 parts by mass of the resin solid content. When the content of the maleimide compound is within the above range, the thermal expansion coefficient of the obtained cured product tends to be further reduced, and the heat resistance tends to be further improved. Only one type of maleimide compound may be used, or two or more types may be used. When two or more types are used, it is preferable that the total amount be within the above range.

[0038] (Epoxy Compound) The epoxy compound is not particularly limited, but a non-halogen-based compound having two or more epoxy groups per molecule is preferred. Specific examples include bisphenol A epoxy resins, bisphenol F epoxy resins, phenol novolac epoxy resins, bisphenol A novolac epoxy resins, biphenyl aralkyl epoxy resins, cresol novolac epoxy resins, multifunctional phenol epoxy resins, naphthalene-modified epoxy resins, naphthalene skeleton-modified novolac epoxy resins, phenol aralkyl epoxy resins, biphenyl epoxy resins, alicyclic epoxy resins, polyol epoxy resins, phosphorus-containing epoxy resins, glycidyl amines, glycidyl esters, compounds in which the double bonds of butadiene or the like are epoxidized, and compounds obtained by reacting hydroxyl group-containing silicone resins with epichlorohydrin. Among these, at least one selected from the group consisting of naphthalene-modified epoxy resins, cresol novolac epoxy resins, and bisphenol A epoxy resins is preferred. The use of such epoxy compounds tends to further improve heat resistance.

[0039] The content of the epoxy compound is preferably 25 to 65 parts by mass relative to 100 parts by mass of the resin solid content, more preferably 30 to 60 parts by mass, and even more preferably 35 to 55 parts by mass. By setting it within this range, metal adhesion, heat resistance, peel strength, and electrical properties tend to be further improved. Only one type of epoxy compound may be used, or two or more types may be used. When two or more types are used, it is preferable that the total amount be within the above range.

[0040] (Cyanate Ester Compound) The cyanate ester compound is not particularly limited, but a compound having two or more cyanate groups in the molecule is preferred. Specific examples include bisphenol A cyanate ester compounds and prepolymers thereof, naphthol aralkyl cyanate ester compounds, 1,3- or 1,4-dicyanatobenzene, 1,3,5-tricyanatobenzene, 1,3-, 1,4-, 1,6-, 1,8-, 2,6- or 2,7-dicyanatonaphthalene, 1,3,6-tricyanatonaphthalene, 4,4-dicyanatobiphenyl, bis(4-dicyanatophenyl)methane, 2,2-bis( Examples of suitable cyanate ester compounds include bis(4-cyanatophenyl)propane, 2,2-bis(3,5-dibromo-4-cyanatophenyl)propane, bis(4-cyanatophenyl)ether, bis(4-cyanatophenyl)thioether, bis(4-cyanatophenyl)sulfone, tris(4-cyanatophenyl)phosphite, tris(4-cyanatophenyl)phosphate, and cyanate ester compounds obtained by reacting novolak with a cyanogen halide. Among these, bisphenol A cyanate ester compounds and prepolymers thereof, and naphthol aralkyl cyanate ester compounds are preferred, and at least one of bisphenol A cyanate ester compounds and naphthol aralkyl cyanate ester compounds is more preferred. Use of such cyanate ester compounds tends to further improve heat resistance.

[0041] The content of the cyanate ester compound is preferably 15 to 45 parts by mass, more preferably 25 to 40 parts by mass, per 100 parts by mass of the resin solid content. By setting it within this range, electrical properties and flame retardancy tend to be further improved. Only one type of cyanate ester compound may be used, or two or more types may be used. When two or more types are used, it is preferable that the total amount be within the above range.

[0042] (Phenol Compound) As the phenol compound, a phenol resin having two or more hydroxyl groups in one molecule is preferred, and generally known compounds can be used.Specific examples thereof include bisphenol A type phenol resin, bisphenol E type phenol resin, bisphenol F type phenol resin, bisphenol S type phenol resin, novolac type phenol resin, bisphenol A novolac type phenol resin, glycidyl ester type phenol resin, aralkyl novolac type phenol resin, biphenyl aralkyl type phenol resin, cresol novolac type phenol resin, multifunctional phenol resin, naphthol resin, naphthol novolac resin, multifunctional naphthol resin, anthracene type phenol resin, naphthalene skeleton modified novolac type phenol resin, phenol aralkyl type phenol resin, naphthol aralkyl type phenol resin, dicyclopentadiene type phenol resin, biphenyl type phenol resin, alicyclic phenol resin, polyol type phenol resin, aminotriazine-containing novolac type phenol resin, phosphorus-containing phenol resin, hydroxyl group-containing silicone resin, etc., but are not particularly limited thereto. Among these, biphenyl aralkyl type phenol resins, naphthol aralkyl type phenol resins, phosphorus-containing phenol resins, and hydroxyl group-containing silicone resins are preferred in terms of flame retardancy.

[0043] The content of the phenol compound is preferably 0.1 parts by mass or more and 10 parts by mass or less, more preferably 1 part by mass or more and 8 parts by mass or less, and even more preferably 2 parts by mass or more and 7 parts by mass or less, relative to 100 parts by mass of the resin solid content. Only one type of phenol compound may be used, or two or more types may be used. When two or more types are used, it is preferable that the total amount is within the above range.

[0044] The thickness of the insulating layer 11 is, for example, 5 μm or more, preferably 10 μm or more, more preferably 15 μm or more, even more preferably 20 μm or more, and even more preferably 25 μm or more. It is also preferably 100 μm or less, more preferably 80 μm or less, even more preferably 60 μm or less, even more preferably 50 μm or less, even more preferably 40 μm or less, and particularly preferably 35 μm or less. By setting the thickness at or above the lower limit, insulation reliability tends to improve. Furthermore, by setting the thickness at or below the upper limit, product thickness tends to be reduced.

[0045] [Metal Foil 12] In this embodiment, the metal foil 12 preferably has a surface roughness Rz of 2.0 μm or less on at least one side, as measured in accordance with JIS B0601 1994. The surface roughness Rz of the metal foil 12 is more preferably 1.8 μm or less, even more preferably 1.5 μm or less, and may even be 1.0 μm or less. Furthermore, while a surface roughness Rz of more than 0 μm is practical, it is preferably 0.2 μm or more, and more preferably 0.5 μm or more. By setting the surface roughness Rz of the metal foil 12 to the lower limit or greater, the adhesion between the insulating layer 11 and the plating layer tends to be further improved. Furthermore, by setting the surface roughness Rz to the upper limit or less, the time required for the process of etching the metal foil 12 tends to be further shortened. In addition, the time required for the flash etching process (e.g., etching that etches a portion of the electroless plating layer 16 to expose the insulating layer 11 in the wiring pattern formation process described below) can be further shortened, and it tends to be easier to form wiring patterns with smaller lines and spaces.

[0046] The thickness of the metal foil 12 is preferably 0.5 μm or more, more preferably 0.8 μm or more, even more preferably 1.0 μm or more, even more preferably 1.2 μm or more, and may be 1.5 μm or more. The thickness of the metal foil 12 is preferably 5.0 μm or less, more preferably 4.0 μm or less, even more preferably 3.0 μm or less, and may be 2.5 μm or less, or 2.0 μm or less. By making the thickness of the metal foil 12 equal to or greater than the lower limit, handleability tends to be improved. By making the thickness equal to or less than the upper limit, the time required for the process of removing the metal foil 12 by etching can be further shortened, thereby reducing the manufacturing cost of the printed wiring board.

[0047] The metal constituting the metal foil 12 is at least one metal selected from copper, aluminum, nickel, titanium, iron, gold, silver, platinum, tin, zinc, tantalum, molybdenum, niobium, and other alloys, and copper is preferred. Examples of copper foil include rolled copper foil and electrolytic copper foil. The metal foil 12 may also be subjected to various surface treatments on its surface, which has a surface roughness Rz of 2.0 μm or less. Examples of such treatments include roughening treatment, heat-resistant treatment, rust-proofing treatment, and silane coupling agent treatment. The metal foil 12 may be subjected to any one of these treatments or a combination of two or more of them. When two or more of the above treatments are performed, the order of roughening treatment, heat-resistant treatment, rust-proofing treatment, and silane coupling agent treatment is preferred. These treatments can be any known surface treatment for metal foils. The surface roughening treatment of the metal foil 12 only needs to be performed on at least the surface on the insulating layer 11 side. The roughening treatment of the metal foil 12 may be, for example, electrolytic roughening treatment.

[0048] [Laminate 13] The laminate 13 can be formed, for example, by placing the insulating layer 11 on the inner layer substrate 14, placing the metal foil 12 thereon, and then heating and pressurizing the laminate. In this case, the metal foil 12 may be placed alone, or a metal foil with a carrier support may be used, with the metal foil 12 facing the insulating layer 11, and the laminate may be formed by peeling off the carrier support. Alternatively, the laminate 13 may be formed, for example, using a resin-layered metal foil in which an insulating resin layer containing a thermosetting resin is formed on the metal foil 12, or a composite sheet in which an insulating resin layer containing a thermosetting resin is formed on the metal foil 12 of a metal foil with a carrier support, with the resin layer serving as the insulating layer 11, placed in contact with the inner layer substrate 14, and then heated and pressurized. Examples of materials constituting the resin layer include those similar to the prepreg or resin sheet described above. The method for providing the metal foil 12 on the surface of the resin sheet is not particularly limited, and can be achieved, for example, by applying a solution (varnish) of a thermosetting resin dissolved in a solvent to the metal foil 12 and drying it. Examples of application methods include a gravure coater, a bar coater, a die coater, a doctor blade, and a baker applicator.

[0049] In this embodiment, it is preferable to provide the metal foil 12 on the surface of the resin layer using a metal foil with a carrier support, which is a laminate of the metal foil 12 and a carrier support. Specifically, for example, a thin copper foil with a carrier copper foil, which has a thickness of 1.5 μm and a surface roughness Rz of 2 μm or less as the metal foil 12 and a carrier copper foil with a thickness of 18 μm as the carrier support, is arranged on the surface of the insulating layer 11 made of a prepreg, a resin sheet, or the like so that the surface of the metal foil 12 with a surface roughness Rz of 2 μm or less is in contact with the surface of the insulating layer 11, and after laminate molding, the carrier copper foil is removed, thereby providing the metal foil 12 on the surface of the insulating layer 11.

[0050] Examples of the carrier support include metal foil and resin film, with metal foil being preferred and copper foil being more preferred. When the carrier support is copper foil, it is often referred to as carrier copper foil. For resin films, the description in paragraph 0031 of WO 2017 / 086418 can be referred to, the contents of which are incorporated herein by reference. The thickness of the carrier support is, for example, 5 μm or more, preferably 8 μm or more, and 100 μm or less, preferably 50 μm or less, and more preferably 30 μm or less. The carrier support-attached metal foil 12 may have other layers (such as an adhesive layer, a release layer, a roughening treatment layer, a heat-resistant treatment layer, a rust-proofing treatment layer, or a silane coupling agent treatment layer) provided between the carrier support and the metal foil 12.

[0051] The heating temperature in the curing step is, for example, preferably 150°C or higher, more preferably 180°C or higher, and even more preferably 200°C or higher. The heating temperature is, for example, preferably 350°C or lower, more preferably 300°C or lower, and even more preferably 250°C or lower. The applied pressure in the curing step is, for example, preferably 1.0 MPa or higher, more preferably 1.5 MPa or higher, and even more preferably 2.0 MPa or higher. The applied pressure is, for example, preferably 5.0 MPa or lower, more preferably 4.5 MPa or lower, and even more preferably 4.0 MPa or lower. As a result, the roughened shape of the metal foil 12 is transferred and cured on the surface of the insulating layer 11 against which the metal foil 12 is abutted.

[0052] <Laminate Forming Process / Non-Through Hole Forming Process> The laminate forming process may also include, after the curing process, a non-through hole forming process in which, for example, as shown in Fig. 1(B) , non-through holes 15 are formed from the metal foil 12 to the inner layer circuits 14B. In the non-through hole forming process, holes are drilled in the metal foil 12 and the insulating layer 11 by laser processing using a carbon dioxide laser or the like, to form the non-through holes 15 that reach the inner layer circuits 14B. Thereafter, as necessary, wet desmearing such as etching, or dry desmearing by plasma treatment or UV treatment is performed to remove smears remaining in the non-through holes 15.

[0053] <Insulating Layer Exposing Step> After the laminate forming step, for example, as shown in Fig. 1(C), the metal foil 12 is removed from the laminate 13 using an etching solution to expose the roughened surface of the insulating layer 11 roughened by the metal foil 12 (insulating layer exposing step). Examples of the etching solution include hydrogen peroxide, sulfuric acid, persulfates, organic acids, hydrochloric acid, and cupric chloride. Etching can be performed by known methods such as spraying and swing immersion.

[0054] Note that the surface of the metal foil 12 is formed with a surface layer, such as a corrosion-resistant or heat-resistant layer, to suppress deterioration due to acid or heat. Therefore, various metal elements contained in the surface of the metal foil 12 remain as residues on the roughened surface of the insulating layer 11 after the metal foil 12 is removed. For the roughened surface of the insulating layer 11 exposed in the insulating layer exposing step, the amount of metal elements contained in Groups 3 to 12 other than the same metal as the metal foil 12, as measured by X-ray photoelectron spectroscopy, is preferably 5 atomic % or more relative to the total amount of elements measured by X-ray photoelectron spectroscopy. Hereinafter, metal elements contained in Groups 3 to 12 other than the same metal as the metal foil 12 are referred to as "predetermined metal elements." This is because specifying the amount of the predetermined metal elements remaining on the roughened surface of the insulating layer 11 in this manner can improve the adhesion between the insulating layer 11 and the wiring formed thereon.

[0055] The reason why the specified metal element is a metal element other than the same metal as the metal foil 12 is to eliminate the influence of metal elements of the metal foil 12, which may remain on the roughened surface of the insulating layer 11. Furthermore, metal elements included in Groups 1 and 2 are excluded from the specified metal elements because these elements may increase or decrease due to contamination, and to eliminate the influence of contamination. Among these, it is preferable that the specified metal element includes at least one selected from the group consisting of chromium, cobalt, nickel, zinc, and molybdenum. This is because these metal elements can further improve the adhesion between the insulating layer 11 and the wiring formed thereon.

[0056] The amount of the predetermined metal element on the roughened surface of the insulating layer 11 exposed in the insulating layer exposing step, as measured by X-ray photoelectron spectroscopy, is preferably 6 atomic % or more, more preferably 30 atomic % or less, and even more preferably 20 atomic % or less, relative to the total amount of elements measured by X-ray photoelectron spectroscopy. This is because if too much metal element remains, it will affect the formation of wiring. The amount of the predetermined metal element on the roughened surface of the insulating layer 11 exposed in the insulating layer exposing step can be adjusted, for example, by appropriately selecting the material of the surface layer formed on the surface of the metal foil 12, or the etching solution and etching conditions used to remove the metal foil 12.

[0057] <Heat Treatment Step> After the insulating layer exposing step, the exposed insulating layer 11 is preferably subjected to a heat treatment, if necessary (heat treatment step). By including the heat treatment step, even when a metal foil 12 with a small surface roughness Rz is used, the adhesion between the insulating layer 11 and the electroless plating layer 16 (described later) is improved, thereby increasing the adhesion between the formed wiring pattern 19 and the insulating layer 11 compared to conventional methods. As a result, it is believed that a finer wiring pattern 19 can be formed than conventional methods. Furthermore, since the wiring pattern 19 can be formed on the insulating layer 11 with a small surface roughness inherent to the metal foil, a semiconductor device with low electrical transmission loss and low energy loss can be obtained. In the heat treatment step, the heating temperature is preferably, for example, 100°C or higher and 200°C or lower, and more preferably 120°C or higher and 180°C or lower. If the heating temperature is too low, the insulating layer will not dry sufficiently, and if it is too high, decomposition of the resin component of the insulating layer will proceed. In the heat treatment step, the heating time is preferably, for example, from 30 minutes to 600 minutes, and more preferably from 60 minutes to 400 minutes. If the heating time is too short, the insulating layer will not be sufficiently dried, and if it is too long, decomposition of the resin component of the insulating layer 11 will proceed.

[0058] 1(D), electroless plating is performed on the roughened surface of the insulating layer 11 to which the roughened shape of the metal foil 12 has been transferred, to form an electroless plated layer 16 (electroless plating step). At that time, if non-through holes 15 are formed in the insulating layer 11 by the non-through hole forming step described above, the electroless plated layer 16 is also formed on the inner walls of the non-through holes 15.

[0059] In this embodiment, even if the electroless plated layer 16 is formed without performing a roughening treatment on the surface of the insulating layer 11 after etching and removing the metal foil 12, it is possible to form an electroless plated layer 16 with excellent adhesion to the insulating layer 11, and thus an electrolytic plated layer 18, which will be described in detail below. This simplifies the manufacturing process and significantly reduces the environmental impact in the method for manufacturing a printed wiring board. In this embodiment, drying is preferably performed after the electroless plating process to remove any encapsulated moisture. As for drying conditions after the electroless plating process, any drying conditions sufficient to remove moisture are effective, but heating at 100°C to 170°C for 1 hour to 5 hours is more preferred. Such drying not only removes moisture but also further improves adhesion between the insulating layer 11 and the metal layer (electroless plated layer 16 and / or wiring pattern 19). The electroless plating is preferably copper electroless plating.

[0060] <Photoresist Film Lamination Step> After the electroless plating step, a photoresist film is laminated by, for example, thermocompression bonding a dry film onto the surface of the electroless plated layer 16 (photoresist film lamination step). The compression temperature is, for example, 50° C. to 140° C., and the compression pressure is, for example, 1 kgf / cm. ２ ~15kgf / cm ２ The pressure bonding time is preferably set to, for example, 5 to 300 seconds.

[0061] <Resist Pattern Formation Step> Next, as shown in FIG. 2(E), the photoresist film is exposed and developed to form a resist pattern 17 (resist pattern formation step). The resist pattern 17 is formed, for example, corresponding to the area from which the electroless plating layer 16 is removed in the etching step described below. During exposure, active energy rays are irradiated onto predetermined portions of the photoresist film, curing the irradiated areas. The active energy rays may be irradiated through a mask pattern, or a direct writing method may be used in which the active energy rays are directly irradiated. The active energy rays are not particularly limited, but examples include ultraviolet light, visible light, electron beams, and X-rays. It is desirable to select an appropriate active energy ray depending on the type of resist. The development is not particularly limited, as long as it dissolves the unexposed portions in a limited manner, but developers such as alkaline aqueous solutions, aqueous developers, and organic solvents are used. Development methods can be performed using known methods, such as spraying, swing immersion, brushing, and scraping.

[0062] <Electrolytic Plating Process, Resist Pattern Removal Process, and Wiring Pattern Formation Process> Next, as shown in FIG. 2(F), electrolytic plating is applied to the electroless plated layer 16 via the resist pattern 17 to form the electrolytic plated layer 18 (electrolytic plating process). The electrolytic plating is preferably copper electrolytic plating. Next, the resist pattern 17 is removed (resist pattern removal process). Thereafter, as shown in FIG. 2(G), the portion of the electroless plated layer 16 exposed by the removal of the resist pattern 17 is removed by etching to expose the insulating layer 11, thereby forming the wiring pattern 19 (wiring pattern formation process). After forming the wiring pattern 19, it is preferable to perform a heat treatment at 150°C to 200°C for 20 to 90 minutes. This is because this can further improve and stabilize the adhesion between the wiring pattern 19 and the insulating layer 11.

[0063] As described above, according to this embodiment, the amount of a predetermined metal element measured by X-ray photoelectron spectroscopy on the roughened surface of the insulating layer 11 exposed in the insulating layer exposing step is set to 5 atomic % or more relative to the total amount of elements measured by X-ray photoelectron spectroscopy, thereby increasing the adhesion between the insulating layer 11 and the wiring and improving the formability of a fine wiring pattern.

[0064] In particular, if the predetermined metal element contains at least one selected from the group consisting of chromium, cobalt, nickel, zinc, and molybdenum, a greater effect can be obtained.

[0065] 3 and 4 show the steps of a method for manufacturing a printed wiring board according to a second embodiment of the present invention. The method for manufacturing a printed wiring board according to this embodiment includes the same steps as those of the first embodiment, except for the specific step in the laminate formation step in which a metal foil 22 having a roughened surface is laminated on at least one surface of an insulating layer 21, and then heated and pressed to form a laminate 23.

[0066] 3A, the laminate formation process in this embodiment includes a curing process in which an insulating layer 21 is formed from a prepreg or a resin sheet in which a base material is impregnated with or coated with a thermosetting resin composition, a metal foil 22 having a roughened surface is laminated on at least one surface of the insulating layer 21, and the insulating layer 21 is cured by heating and pressurizing. The configurations of the prepreg or resin sheet and the metal foil 22, as well as the heating temperature and pressure in the curing process, are the same as those in the first embodiment. The thicknesses of the insulating layer 21 and the metal foil 22 are also the same as those in the first embodiment.

[0067] The laminate forming step in this embodiment may also include, after the curing step, a through-hole forming step of forming through-holes 24 that penetrate the insulating layer 21 and the metal foil 22, as shown in Fig. 3(B) . In the through-hole forming step, the through-holes 24 are formed by laser processing using a carbon dioxide laser or the like. Thereafter, as necessary, wet desmearing such as etching, or dry desmearing using plasma treatment or UV treatment is performed to remove smears remaining in the through-holes 24.

[0068] After the laminate formation step, for example, in the same manner as in the first embodiment, an insulating layer exposing step (see FIG. 3(C)), a heat treatment step, an electroless plating step (see FIG. 3(D)), a photoresist film laminating step, a resist pattern forming step (see FIG. 4(E)), an electrolytic plating step (see FIG. 4(F)), a resist pattern peeling step, and a wiring pattern forming step (see FIG. 4(G)) are performed as necessary.

[0069] Specifically, as shown in FIG. 3C, the metal foil 22 is first removed from the laminate 23 using an etching solution to expose the roughened surface of the insulating layer 21 roughened by the metal foil 22 (insulating layer exposing step). The amount of a predetermined metal element measured by X-ray photoelectron spectroscopy on the roughened surface of the insulating layer 21 exposed in the insulating layer exposing step is the same as in the first embodiment. Next, for example, if necessary, the exposed insulating layer 21 is subjected to a heat treatment (heat treating step). Subsequently, for example, as shown in FIG. 3D, electroless plating is performed on the roughened surface of the insulating layer 21 to which the roughened shape of the metal foil 22 has been transferred to form an electroless plated layer 25 (electroless plating step). Next, for example, a dry film is thermocompression-bonded to the surface of the electroless plated layer 25 to form a photoresist film (photoresist film laminating step). Next, for example, as shown in FIG. 4E, the photoresist film is exposed and developed to form a resist pattern 26 (resist pattern forming step). Next, as shown in Fig. 4(F), electrolytic plating is applied to the electroless plated layer 25 via the resist pattern 26 to form an electrolytic plated layer 27 (electrolytic plating step). Next, the resist pattern 26 is stripped (resist pattern stripping step). Thereafter, as shown in Fig. 4(G), the portion of the electroless plated layer 25 exposed by the stripping of the resist pattern 26 is removed by etching to form a wiring pattern 28 (wiring pattern formation step). The specific conditions for each step are the same as those in the first embodiment.

[0070] As in the first embodiment, in this embodiment, the amount of a specified metal element measured by X-ray photoelectron spectroscopy on the roughened surface of the insulating layer 21 exposed in the insulating layer exposing step is 5 atomic % or more relative to the total amount of elements measured by X-ray photoelectron spectroscopy, thereby increasing the adhesion between the insulating layer 21 and the wiring and improving the formability of a fine wiring pattern.

[0071] The present invention will be explained in more detail below with reference to examples. The materials, amounts used, ratios, processing details, processing procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. If the measuring instruments used in the examples are difficult to obtain due to discontinuation, etc., measurements can be made using other instruments with equivalent performance. In the following examples, the heating temperature and pressure applied are the set temperature and set pressure of the instruments.

[0072] Synthesis Example 1: Synthesis of naphthol aralkyl cyanate ester compound (SNCN) 300 g (1.28 mol in terms of OH groups) of 1-naphthol aralkyl resin (manufactured by Nippon Steel Chemical & Material Co., Ltd.) and 194.6 g (1.92 mol) of triethylamine (1.5 mol per mol of hydroxy groups) were dissolved in 1,800 g of dichloromethane, and the resulting solution was designated Solution 1. 125.9 g (2.05 mol) of cyanogen chloride (1.6 mol per mol of hydroxy groups), 293.8 g of dichloromethane, 194.5 g (1.92 mol) of 36% hydrochloric acid (1.5 mol per mol of hydroxy groups), and 1,205.9 g of water were added over 30 minutes with stirring while maintaining the liquid temperature at −2° C. to −0.5° C. After the addition of Solution 1, the mixture was stirred at the same temperature for 30 minutes, and then a solution (Solution 2) prepared by dissolving 65 g (0.64 mol) of triethylamine (0.5 mol per mol of hydroxyl groups) in 65 g of dichloromethane was added over 10 minutes. After the addition of Solution 2, the mixture was stirred at the same temperature for 30 minutes to complete the reaction. The reaction solution was then allowed to stand, and the organic and aqueous phases were separated. The resulting organic phase was washed five times with 1,300 g of water. The electrical conductivity of the wastewater from the fifth water wash was 5 μS / cm, confirming that the ionic compounds were sufficiently removed by washing with water. The organic phase after water washing was concentrated under reduced pressure and finally concentrated to dryness at 90°C for 1 hour, yielding 331 g of the desired naphthol aralkyl cyanate ester compound (SNCN) (orange viscous substance). The weight-average molecular weight Mw of the resulting SNCN was 600. The IR spectrum of SNCN measured at 2250 cm －１ The absorption of the cyanate ester group was observed, and the absorption of the hydroxyl group was not observed.

[0073] Example 1 A test piece was prepared as follows.

[0074] <Prepreg Preparation Step> 35 parts by mass of the SNCN obtained in Synthesis Example 1, 25 parts by mass of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane (BMI-70, manufactured by K.I. Kasei Co., Ltd.), and 40 parts by mass of polyoxynaphthylene epoxy resin (HP-6000, manufactured by DIC Corporation) were mixed and dissolved in methyl ethyl ketone. Next, 200 parts by mass of spherical fused silica (SC2050MB, manufactured by Admatechs Co., Ltd.), 10 parts by mass of silicone resin powder (Tospearl 120, manufactured by Momentive Performance Materials Japan, LLC), and 15 parts by mass of silicone rubber powder whose surface was coated with silicone resin (silicone composite powder KMP-600, manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed with this solution to prepare a varnish. The obtained varnish was diluted with methyl ethyl ketone, and applied to an E-glass woven fabric having a thickness of 0.020 mm by impregnation, and then dried by heating at 160° C. for 4 minutes to obtain prepreg 1.

[0075] <Laminate Forming Step / Curing Step (See FIG. 1(A)>> Furthermore, a glass cloth-based BT resin copper-clad laminate (conductor thickness 12 μm, thickness 0.1 mm, HL832NS manufactured by Mitsubishi Gas Chemical Company, Inc.) was prepared as the inner layer substrate 14, and its surface was roughened. Specifically, first, as a pretreatment, the inner layer substrate 14 was cleaned with a residue remover (CA5330 manufactured by MEC Co., Ltd.), and after rinsing with water, the copper surface was roughened with a micro-etching agent (CZ8101 manufactured by MEC Co., Ltd.), and after rinsing with water, rust prevention was performed with a rust inhibitor (CL8300 manufactured by MEC Co., Ltd.), followed by rinsing with water and drying. The etching depth by the micro-etching agent was 1 μm. A horizontal line spray device was used for roughening.

[0076] After roughening the surface of the inner layer substrate 14, a 1.5 μm copper foil with a carrier copper foil of 18 μm in thickness (thickness 1.5 μm, surface roughness Rz 1.3 μm: manufactured by Mitsui Mining & Smelting Co., Ltd., product name: MT18FL) containing a metal foil 12 whose surface had been roughened was placed on top of the inner layer substrate 14 (both the front and back sides) as an insulating layer 11, via the prepreg 1 produced in the previous prepreg production process, and laminated in a vacuum press under conditions of a pressure of 2.5±0.2 MPa, a temperature of 220±2°C, and a holding time of 60 minutes, to produce a laminate 13.

[0077] <Insulating Layer Exposing Step (See FIG. 1(C))> The carrier copper foil on the surface of the prepared laminate 13 was peeled off, and the remaining copper foil, which was the metal foil 12, was removed using an etching solution to expose the roughened surface of the insulating layer 11. The etching solution used was CPE-770D (manufactured by Mitsubishi Gas Chemical Company, Inc.), and copper etching was performed by treating for 3 minutes at a liquid temperature of 35°C. The liquid composition of the etching solution CPE-770D included water, 2.1 w / v% hydrogen peroxide, 4 w / v% sulfuric acid, and 2.6 w / v% alcohol as an auxiliary agent, and the chlorine content excluding the solvent was less than 0.1 wt% when the total solute components were 100 wt%. The etching device used was a horizontal line spray type (manufactured by Tokyo Kakoki Co., Ltd.).

[0078] <Electroless Plating Step (See FIG. 1(D))> After the insulating layer exposing step, the laminate 13 from which the metal foil 12 had been removed was racked on a plating jig, and electroless copper plating was performed on the roughened surface of the insulating layer 11 using a device manufactured by Almex Technologies Co., Ltd. that can be immersed and oscillated in an electroless copper plating bath. The chemical solution used was a mixture of Thru-Cup PEA (manufactured by Uemura Kogyo Co., Ltd.) and formaldehyde. The temperature of the chemical solution for electroless copper plating was 36°C, and the treatment time was 10 minutes, forming an electroless plated layer 16 with a thickness of 0.4 μm.

[0079] <Electrolytic Plating Step (See FIG. 2(F))> After the electroless plating step, an immersion-type apparatus (manufactured by Almex Technologies Co., Ltd.) was used for electrolytic copper plating, and a phosphorus-containing copper anode, which was a soluble anode, was used to apply a direct current of 1 A / dm ２ The copper plating bath temperature was set to 22°C, and additives for leveler, brightener, and polymer from CU-BRITE TF4 (manufactured by JCU Corporation) were used as a through-hole filling solution. The copper plating bath used was a mixture of copper sulfate, sulfuric acid, and hydrochloric acid.

[0080] Example 2: Test pieces were obtained in the same manner as in Example 1, except that the metal foil 12 laminated to the inner substrate 14 via the insulating layer 11 in the laminate formation process was changed, and the etching solution and treatment temperature used in the insulating layer exposing process were changed. Specifically, in the laminate formation process, a 18 μm-thick 1.5 μm copper foil with a carrier copper foil (thickness: 1.5 μm, surface roughness Rz: 1.4 μm; manufactured by Mitsui Mining & Smelting Co., Ltd., product name: MT18SP2) containing the surface-roughened metal foil 12 was placed on top of the inner substrate 14 (both front and back sides) via the prepreg 1 prepared in Example 1 as the insulating layer 11, to produce a laminate 13. In the insulating layer exposing process, copper etching was performed using an aqueous solution of hydrochloric acid and cupric chloride as the etching solution at a solution temperature of 48°C. The etching solution contained water and 120 w / v% hydrochloric acid.

[0081] [Example 3] Test pieces were obtained in the same manner as in Example 2, except that the metal foil 12 laminated on the inner layer substrate 14 via the insulating layer 11 in the laminate formation step was changed. Specifically, in the laminate formation step, the prepreg 1 produced in Example 1 was placed on top of the inner layer substrate 14 (both the front and back sides) as the insulating layer 11, and a 12 μm thick copper foil (thickness 12 μm, surface roughness Rz 2.0 μm: manufactured by Mitsui Mining & Smelting Co., Ltd., product name: 3EC-M2S-VLP) whose surface had been roughened was placed as the metal foil 12, to produce a laminate 13.

[0082] Example 4 Test pieces were obtained in the same manner as in Example 2, except that the metal foil 12 laminated on the inner layer substrate 14 via the insulating layer 11 in the laminate formation step was changed. Specifically, in the laminate formation step, the prepreg 1 produced in Example 1 was placed on top of the inner layer substrate 14 (both the front and back sides) as the insulating layer 11, and a 12 μm thick copper foil (thickness 12 μm, surface roughness Rz 1.8 μm: manufactured by Fukuda Metal Foil and Powder Co., Ltd., product name: CF-V9W-SV-12) whose surface had been roughened was placed as the metal foil 12, to produce a laminate 13.

[0083] Example 5 Test pieces were obtained in the same manner as in Example 2, except that the metal foil 12 laminated to the inner layer substrate 14 via the insulating layer 11 in the laminate formation step was changed. Specifically, in the laminate formation step, a laminate 13 was produced by placing, on the top (front and back) of the inner layer substrate 14 (both the front and back sides) the prepreg 1 produced in Example 1 as the insulating layer 11, a 1.5 μm copper foil with a carrier copper foil of 18 μm in thickness (thickness 1.5 μm, surface roughness Rz 1.1 μm: manufactured by JX Nippon Mining & Metals Corporation, product name: JXUT-I) including the metal foil 12 whose surface had been roughened.

[0084] Example 6 Prepreg Preparation Step A varnish was prepared by mixing 35 parts by mass of the SNCN obtained in Synthesis Example 1, 15 parts by mass of bibiphenylaralkyl maleimide (MIR-3000, manufactured by Nippon Kayaku Co., Ltd.), 10 parts by mass of a polyphenylene ether compound having a styrene structure at the end (OPE-2St1200, manufactured by Mitsubishi Gas Chemical Company, Inc.), 10 parts by mass of a styrene-butadiene block copolymer (TR2630, manufactured by JSR Corporation), 20 parts by mass of an α-methylstyrene polymer (Crystalex 3085, manufactured by Eastman Chemical Co.), and 150 parts by mass of spherical fused silica (SC2050MB, manufactured by Admatechs Co., Ltd.). The obtained varnish was diluted with methyl ethyl ketone, impregnated and coated onto a 0.020 mm thick NE glass woven fabric, and heated and dried at 160°C for 4 minutes to obtain prepreg 2.

[0085] Next, in the laminate formation process, a metal foil 12 was laminated on top of the inner layer substrate 14 (both the front and back sides) via the prepreg 2 prepared in the previous prepreg preparation process as the insulating layer 11. A test piece was obtained in the same manner as in Example 1.

[0086] [Example 7] A test piece was obtained in the same manner as in Example 2, except that in the laminate formation process, metal foil 12 was laminated on top of inner layer substrate 14 (both the front and back sides) via prepreg 2 prepared in the previous prepreg preparation process as insulating layer 11.

[0087] [Comparative Example 1] Except for changing the etching solution and treatment temperature used in the insulating layer exposing step, a test piece was obtained in the same manner as in Example 1. Specifically, in the insulating layer exposing step, an aqueous solution of hydrochloric acid and cupric chloride was used as the etching solution, and copper etching was performed at a solution temperature of 48°C. The etching solution contained water and 120 w / v% hydrochloric acid.

[0088] [Comparative Example 2] A test piece was obtained in the same manner as in Example 6, except that the etching solution and treatment temperature used in the insulating layer exposing step were changed. Specifically, in the insulating layer exposing step, a solution of hydrochloric acid and cupric chloride was used as the etching solution, and copper etching was performed at a solution temperature of 48°C. The etching solution contained water and 120 w / v% hydrochloric acid.

[0089] (Characteristics Evaluation) The characteristics of Examples 1 to 7 and Comparative Examples 1 and 2 were measured by the following methods.

[0090] <Measurement of the amount of a predetermined metal element on the roughened surface of the insulating layer 11> For each example and comparative example, surface element analysis was performed by X-ray photoelectron spectroscopy on the roughened surface of the insulating layer 11 exposed in the insulating layer exposing step. A Quantera II X-ray photoelectron spectrometer manufactured by ULVAC-PHI, Inc. was used as the X-ray photoelectron spectrometer, and measurements were performed under the following conditions.

[0091] Narrow scan analysis X-ray used: Al-Kα ray (output: 50 W, 15 kV) Neutralization electron gun: used Time per step: 20 ms Energy step: 0.1 eV Pass energy: 112 eV Number of accumulations: 5 The values ​​obtained by the above measurement were quantitatively converted using a relative sensitivity coefficient incorporated in the analysis software provided with the above device.

[0092] As a result, the amount of the predetermined metal element relative to the amount of all elements measured by X-ray photoelectron spectroscopy was measured. The obtained results are shown in Tables 1 and 2.

[0093] <Evaluation of Peel Strength> The peel strength of each test piece was measured to determine its strength. Peel strength was measured by fixing the lower layer of the test piece to a plate or the like, pulling the edge of the plating layer perpendicular to the fixing plate direction, and measuring the load required for peeling. The results are shown in Tables 1 and 2.

[0094]

[0095]

[0096] As shown in Tables 1 and 2, in the evaluation of peel strength, Examples 1 to 7 had higher peel strength than Comparative Examples 1 and 2. That is, it was found that according to the present examples, the wiring adhesion strength resulting from the peel strength can be strengthened, and the formability of a fine wiring pattern can be improved.

[0097] It can be used in the manufacture of printed wiring boards.

[0098] 11...insulating layer, 12...metal foil, 13...laminated board, 14...inner layer substrate, 14A...insulating board, 14B...inner layer circuit, 15...blind hole, 16...electroless plated layer, 17...resist pattern, 18...electrolytic plated layer, 19...wiring pattern, 21...insulating layer, 22...metal foil, 23...laminated board, 24...through hole, 25...electroless plated layer, 26...resist pattern, 27...electrolytic plated layer, 28...wiring pattern

Claims

1. A method for manufacturing a semiconductor device comprising the steps of: laminating a metal foil having a roughened surface on at least one surface of an insulating layer, and applying heat and pressure to form a laminate; removing the metal foil from the laminate using an etching solution to expose the roughened surface of the insulating layer that has been roughened by the metal foil; electroless plating, forming an electroless plated layer by electrolessly plating the roughened surface of the insulating layer; a photoresist film laminating step of laminating a photoresist film on the surface of the electroless plated layer; a resist pattern forming step of exposing and developing the photoresist film to light to form a resist pattern; electrolytic plating, forming an electroless plated layer by electrolytic plating the electroless plated layer through the resist pattern; a resist pattern peeling step of peeling off the resist pattern; and a wiring pattern forming step of etching away the portion of the electroless plated layer exposed by peeling off the resist pattern to form a wiring pattern. a method for manufacturing a printed wiring board, characterized in that the amount of metal elements included in Groups 3 to 12 other than the same metal as the metal foil, measured by X-ray photoelectron spectroscopy on the roughened surface of the insulating layer exposed in the insulating layer exposing step, is 5 atomic % or more with respect to the total amount of elements measured by X-ray photoelectron spectroscopy.

2. The method for manufacturing a printed wiring board according to claim 1, characterized in that the metal element contains at least one selected from the group consisting of chromium (Cr), cobalt (Co), nickel (Ni), zinc (Zn), and molybdenum (Mo).

3. The method for manufacturing a printed wiring board according to claim 1, characterized in that the insulating layer contains at least one thermosetting compound selected from the group consisting of polyphenylene ether compounds, maleimide compounds, epoxy compounds, cyanate ester compounds, and phenol compounds.

4. The method for manufacturing a printed wiring board according to claim 1, characterized in that the laminate formation process includes a curing process in which the insulating layer is made of a material containing a thermosetting compound, the insulating layer and the metal foil are placed in this order on an inner layer substrate on which an inner layer circuit has been formed, and heat and pressure are applied to harden the insulating layer, and a blind hole formation process in which blind holes are formed from the metal foil to reach the inner layer circuit.

5. The method for manufacturing a printed wiring board according to claim 1, characterized in that the laminate formation process comprises: a curing process in which the insulating layer is formed from a prepreg or a resin sheet in which a thermosetting resin composition is impregnated or applied to a base material, the metal foil is laminated on at least one surface of the insulating layer, and the insulating layer is cured by heating and pressurizing; and a through-hole formation process in which through-holes that penetrate the insulating layer and the metal foil are formed.

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