Method of manufacturing a wiring substrate and wiring substrate

Abstract

This invention discloses a method for manufacturing a wiring substrate, comprising: a step of pretreating the surface of a metal layer exposed in an opening by contacting it with a pretreatment solution at a predetermined pretreatment temperature; and a step of forming a copper plating layer on the metal layer by electrolytic plating. The resist layer and the pretreatment solution are selected such that the mass change rate of the resist layer when immersed in the pretreatment solution before exposure and development is -2.0% by mass or more. The mass change rate is calculated using the formula: Mass Change Rate (mass%) = {(W1 - W0) / W0} × 100. W1 is the mass of the resist layer after immersing the laminate having the resist layer 3 and copper foil in the pretreatment solution at the pretreatment temperature for 30 minutes.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a wiring board and the wiring board itself. Background Technology

[0002] To meet the requirements of miniaturization, lightweighting, and high-speed operation of electronic devices, the wiring substrates constituting these devices need to have wiring with minute widths. Semi-additive plating (SAP) and modified semi-additive plating (MSAP) methods are widely used to form such wiring (Patent Document 1). These methods typically involve forming a copper plating layer on a metal layer through electrolytic plating.

[0003] Previous technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2004-6773 Summary of the Invention

[0006] The technical problem to be solved by the invention

[0007] When a copper plating layer is formed on a metal layer used as a seed layer through electrolytic plating, tiny black portions with a width of less than 0.3 μm are sometimes observed within the copper plating layer near the interface between the metal layer and the copper plating layer. These black portions are estimated to be tiny voids. Since these black portions are extremely small voids, they are unlikely to significantly affect the characteristics of the wiring itself. However, as the wiring width is further miniaturized, if there are many such tiny voids, the adhesion between the copper plating layer and the metal layer may be insufficient.

[0008] One aspect of the present invention relates to a method for suppressing the formation of minute black portions near the interface between the metal layer and the copper plating when manufacturing a wiring substrate using a method comprising forming a copper plating layer on a metal layer by electrolytic plating.

[0009] means for solving technical problems

[0010] One aspect of the present invention relates to a method for manufacturing a wiring substrate, the method comprising: a step of forming a photoresist layer on a metal layer disposed on a support; a step of forming a pattern including openings for exposing the metal layer on the photoresist layer by exposure and development of the photoresist layer; a step of pretreating the surface of the metal layer exposed in the openings by contacting it with a pretreatment solution at a predetermined pretreatment temperature; and a step of forming a copper plating layer on the metal layer by electrolytic plating. The photoresist layer and the pretreatment solution are selected such that the mass change rate of the photoresist layer when immersed in the pretreatment solution before exposure and development is -2.0% by mass or more. The mass change rate is a value calculated by the following formula.

[0011] Mass change rate (mass%) = {(W1-W0) / W0} × 100

[0012] W0 is the mass of the resist layer before immersion in the pretreatment solution, and W1 is the mass of the resist layer after immersing the laminate having the resist layer and a single-sided copper foil covering the resist layer in the pretreatment solution at the pretreatment temperature for 30 minutes.

[0013] Invention Effects

[0014] According to one aspect of the present invention, a method is provided in which, when manufacturing a wiring substrate using a method comprising forming a copper plating layer on a metal layer by electrolytic plating, the generation of minute black portions near the interface between the metal layer and the copper plating layer is suppressed. Attached Figure Description

[0015] Figure 1 This is a cross-sectional view illustrating an example of a method for manufacturing a wiring board.

[0016] Figure 2 This is an example of binarizing an electron microscope image of the area near the interface between the metal layer and the copper plating. Detailed Implementation

[0017] This invention is not limited to the following examples.

[0018] Figure 1 This is a cross-sectional view illustrating an example of a method for manufacturing a wiring board. Figure 1 The method shown includes, in sequence: a step of forming a metal layer 20 on one main surface of a plate-shaped support 1; a step of forming a resist layer 3 on the metal layer 20; a step of forming a pattern including an opening 3A for exposing the metal layer 20 on the resist layer 3 by exposure and development of the resist layer 3; a step of pre-treating the surface of the metal layer 20 exposed in the opening 3A by contacting it with a pre-treatment solution at a predetermined pre-treatment temperature; a step of forming a copper plating layer 21 on the metal layer 20 by electrolytic plating; a step of removing the resist layer 3 to expose the portion of the metal layer 20 not covered by the copper plating layer 21; and a step of removing the exposed portion of the metal layer 20 to form a wiring substrate 10 having a wiring 2 having a metal layer 20 and a copper plating layer 21 and a support 1.

[0019] The outermost layer of the side of the support 1 where the metal layer 20 is located is typically composed mainly of an insulating layer. The insulating layer, which is the outermost layer of the support 1, can be, for example, an additional insulating resin layer. The support 1 may include wiring connected to the wiring 2. The support 1 may include a laminate, i.e., an insulating substrate, formed from multiple prepregs.

[0020] The metal layer 20 functions as a seed layer for electrolytic plating. The metal layer 20 can be, for example, a metal plating formed by electroless plating, a metal foil such as copper foil, a layer formed by vapor deposition such as sputtering, or a sintered metal layer. A sintered metal layer is formed by heating a coating containing metal particles to sinter the metal particles. The metal constituting the metal layer 20 can include, for example, at least one metal selected from the group consisting of copper, gold, silver, tungsten, molybdenum, tin, cobalt, chromium, iron, and zinc. The metal layer 20 can be a single layer or composed of two or more layers. The thickness of the metal layer 20 can be, for example, 0.1 to 2.0 μm.

[0021] The arithmetic surface roughness Ra of the surface of the metal layer 20 opposite to the support 1 can be 0.20 to 0.30 μm. The average height Rc of the surface of the metal layer 20 opposite to the support 1 can be 0.7 to 1.3 μm. If the arithmetic surface roughness Ra and / or the average height Rc are within this range, it is easier to obtain better results from the viewpoint of reducing the black portion in the copper plating.

[0022] Regarding the resist layer 3, it can be formed from a material selected from photosensitive resist materials commonly used for forming wiring, based on the rate of mass change caused by impregnation in the pretreatment solution as described later. The thickness of the resist layer 3 can be, for example, 10 to 50 μm.

[0023] The resist material used to form the resist layer 3 can be, for example, a photosensitive resin composition comprising an adhesive polymer, a photopolymerizable compound having olefinic unsaturated bonds, and a photopolymerization initiator.

[0024] The adhesive polymer can be, for example, a copolymer containing benzyl (meth)acrylate or its derivatives, styrene or styrene derivatives, alkyl (meth)acrylate and (meth)acrylic acid as monomer units.

[0025] Specific examples of benzyl acrylate derivatives constituting adhesive polymers include 4-methylbenzyl acrylate, 4-ethylbenzyl acrylate, 4-tert-butylbenzyl acrylate, 4-methoxybenzyl acrylate, 4-ethoxybenzyl acrylate, 4-hydroxybenzyl acrylate, and 4-chlorobenzyl acrylate.

[0026] Specific examples of styrene derivatives that constitute adhesive polymers include vinyltoluene, p-methylstyrene, and p-chlorostyrene.

[0027] The alkyl (meth)acrylate constituting the adhesive polymer can be an ester compound formed from (meth)acrylic acid and a linear or branched aliphatic alcohol having 1 to 12 carbon atoms. The aliphatic alcohol can have 1 to 8 or 1 to 4 carbon atoms. Specific examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate.

[0028] The proportion of monomer units derived from benzyl (meth)acrylate or its derivatives in the adhesive polymer, based on the mass of the adhesive polymer, can be 50–80% by mass, 50–75% by mass, 50–70% by mass, or 50–65% by mass. The proportion of monomer units derived from styrene or styrene derivatives in the adhesive polymer, based on the mass of the adhesive polymer, can be 5–40% by mass or 5–35% by mass. The proportion of monomer units derived from alkyl (meth)acrylate in the adhesive polymer, based on the mass of the adhesive polymer, can be 1–20% by mass, 1–15% by mass, 1–10% by mass, or 1–5% by mass. The proportion of monomer units derived from (meth)acrylic acid in the adhesive polymer, based on the mass of the adhesive polymer, can be 5–30% by mass, 5–25% by mass, or 10–25% by mass.

[0029] The weight-average molecular weight (Mw) of the adhesive polymer can be 20,000–150,000, 30,000–100,000, 40,000–80,000, or 40,000–60,000. The weight-average molecular weight mentioned herein represents the standard polystyrene conversion value determined by gel permeation chromatography (GPC).

[0030] The acid value (mgKOH / g) of the adhesive polymer can be 13–78, 39–65, or 52–62. The acid value described herein indicates the amount (mg) of potassium hydroxide required to neutralize 1g of the adhesive polymer.

[0031] Specific examples of photopolymerizable compounds having olefinic unsaturated bonds include bisphenol A (meth)acrylate compounds, hydrogenated bisphenol A (meth)acrylate compounds, polyalkylene glycol (meth)acrylates, urethane monomers, pentaerythritol (meth)acrylates, and trimethylolpropane (meth)acrylates. These can be used alone or in combination of two or more. Bisphenol A di(meth)acrylate compounds can be, for example, compounds represented by the following general formula (1).

[0032]

[0033] In formula (1), R independently represents a hydrogen atom or a methyl group. EO and PO represent oxyethylidene and oxypropylidene, respectively. m1, m2, n1, and n2 independently represent 0–40, m1+m2 is 1–40, and n1+n2 is 0–20. Either EO or PO can be on the phenolic hydroxyl side. m1, m2, n1, and n2 represent the amount of EO or PO, respectively. Compounds with an average m1+m2 value of less than 5 and compounds with an average m1+m2 value of 6–40 can be combined.

[0034] Polyalkylene glycol (meth)acrylates can be compounds represented by the following formula (2). As photopolymerizable compounds with olefinic unsaturated bonds, bisphenol A-type di(meth)acrylate compounds and compounds represented by the following formula (2) can be combined.

[0035]

[0036] In equation (2), R 14 and R 15 Each can be used independently to represent a hydrogen atom or a methyl group; EO and PO have the same meaning as described above. 1 Indicates 1 to 30, r 1 and r 2 Representing 0 to 30 respectively, r 1 +r 2 The range is 1 to 30. As an example of a commercially available product representing the compound represented by formula (2), R can be cited. 14 and R 15 Methyl, r 1 +r 2 =4 (average), s 1 =12 (average) vinyl compound (manufactured by ShowaDenko Materials Co., Ltd., product name: FA-023M).

[0037] Specific examples of photopolymerization initiators include benzophenone, N,N'-tetramethyl-4,4'-diaminobenzophenone (Mischel ketone), N,N'-tetraethyl-4,4'-diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)-butanone-1, and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinyl-acetone-1, etc.; aromatic ketones such as 2-ethylanthraquinone, phenanthrenequinone, 2-tert-butylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,3-diphenylanthraquinone, 1-chloroanthraquinone, 2-methylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthrenequinone, and 2-methyl-1,4-naphthoquinone. Quinones and quinones such as 2,3-dimethylanthraquinone; benzoin ether compounds such as benzoin methyl ether, benzoin ethyl ether, and benzoin phenyl ether; benzoin compounds such as benzoin, methyl benzoin, and ethyl benzoin; benzyl derivatives such as benzyl dimethyl ketal; 2,4,5-triaryl imidazole dimers such as 2-(o-chlorophenyl)-4,5-diphenylimidazolium dimer, 2-(o-chlorophenyl)-4,5-di(methoxyphenyl)imidazolium dimer, 2-(o-fluorophenyl)-4,5-diphenylimidazolium dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazolium dimer, and 2-(p-methoxyphenyl)-4,5-diphenylimidazolium dimer; acridine derivatives such as 9-phenylacridine and 1,7-bis(9,9'-acridyl)heptane; N-phenylglycine; N-phenylglycine derivatives; and coumarin compounds. These can be used alone or in combination of two or more types. Photopolymerization initiators may contain 2,4,5-triarylimidazolium dimers, and in particular may contain 2-(o-chlorophenyl)-4,5-diphenylimidazolium dimers.

[0038] The content of the binder polymer in the photosensitive resin composition, relative to 100 parts by weight of the combined binder polymer and photopolymerizable compound, can be 40–80 parts by weight, 45–75 parts by weight, or 50–70 parts by weight. The content of the photopolymerization initiator in the photosensitive resin composition, relative to 100 parts by weight of the combined binder polymer and photopolymerizable compound, can be 0.01–5 parts by weight, 0.1–4.5 parts by weight, or 1–4 parts by weight.

[0039] The photosensitive resin composition may contain other components as needed. Examples of other components include photopolymerizable compounds having cyclic ether groups capable of polymerizing cationic groups, cationic polymerization initiators, sensitizers, dyes such as malachite green, photochromic agents such as tribromomethylphenyl sulfone and leuco crystal violet, thermochromic inhibitors, plasticizers such as p-toluenesulfonamide, pigments, fillers, defoamers, flame retardants, stabilizers, adhesion promoters, leveling agents, peel accelerators, antioxidants, fragrances, developers, and thermocrosslinking agents. The content of other components may be approximately 0.01 to 20 parts by weight, respectively, relative to the total mass of the adhesive polymer and the photopolymerizable compound per 100 parts by weight.

[0040] The total content of the binder polymer, photopolymerizable compound and photopolymerization initiator in the photosensitive resin composition may be 90-100% by mass or 95-100% by mass relative to the total mass of the components other than the solvent in the photosensitive resin composition.

[0041] To form the resist layer 3, a resist film containing a photosensitive resin composition can be laminated onto the metal layer 20, or a photosensitive resin composition containing a solvent can be coated onto the metal layer 20 and the solvent removed from the coating.

[0042] A resist layer 3 having a pattern including an opening 3A is formed by exposing a portion of the resist layer 3 and developing the exposed resist layer 3. The exposure and development can be performed using conventional methods known to those skilled in the art. The fine pattern including the opening 3A exposing the metal layer 20 is formed by exposure via a photomask. The developing solution used can be an alkaline aqueous solution such as an aqueous sodium carbonate solution.

[0043] Next, the surface of the metal layer 20 exposed within the opening 3A is pretreated by contacting a pretreatment solution at a predetermined pretreatment temperature. For example, the surface of the metal layer 20 can be pretreated by immersing an intermediate structure comprising a support 1, the metal layer 20, and a patterned resist layer 3 in a pretreatment solution adjusted to a predetermined pretreatment temperature. The pretreatment temperature can be appropriately set depending on the type of pretreatment solution, but it can be, for example, in the range of 20 to 50°C. The immersion time in the pretreatment solution can be, for example, 1 to 8 minutes.

[0044] Regarding the pretreatment solution, it can be selected from those commonly used for electroplating based on the mass change rate of the immersion in the pretreatment solution based on the resist layer 3, as described later. The pretreatment solution can be acidic or contain alcohol. The alcohol content, based on the mass of the pretreatment solution, can be 0.2% to 5% by mass.

[0045] The pretreatment solution can be, for example, an acidic aqueous solution containing acid components, electroplating additives, and reducing agents.

[0046] The acid component can be an organic acid, an inorganic acid, or a combination thereof. Specific examples include sulfuric acid; alkyl sulfonic acids such as methanesulfonic acid and propanesulfonic acid; alkyl alcohol sulfonic acids such as hydroxyethanesulfonic acid and propanol sulfonic acid; and carboxylic acids such as citric acid, tartaric acid, and formic acid. One of these can be used alone or in combination of two or more. The concentration of the acid component in the pretreatment solution, based on the volume of the pretreatment solution, can be 10–300 g / L or 50–200 g / L.

[0047] Additives for electrolytic plating can be, for example, polyether compounds, organosulfur compounds, or combinations thereof. Examples of polyether compounds include polyethylene glycol, polypropylene glycol, and their derivatives. Organosulfur compounds are copper plating precipitation promoters, sometimes called brighteners; examples include 3-mercaptopropanesulfonic acid and disodium bis(3-sulfopropyl)disulfide. The concentration of the additive in the pretreatment solution, based on the volume of the pretreatment solution, can be from 0.1 to 10000 mg / L.

[0048] Examples of reducing agents include hypophosphites, phosphites, dimethylamine borane, trimethylamine borane, hydrazine derivatives, boron hydride salts, aldehydes (e.g., formalin, glyoxylic acid), titanium trichloride, catechol, resorcinol, hydroquinone, ascorbate, phenylenediamine, and hypophosphinoic acid derivatives. These can be used alone or in combination of two or more. The concentration of the reducing agent in the pretreatment solution, based on the volume of the pretreatment solution, can be 0.0001–0.1 mol / L.

[0049] The pretreatment solution may further contain a surfactant selected from alkylbenzene sulfonates and compounds containing an acetylene group. The pretreatment solution may contain carboxylic acids or alkylsulfonic acids, inorganic acids selected from hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid, alkylbenzene sulfonates, and compounds containing an acetylene group. In this case, the content of carboxylic acids and alkylsulfonic acids, based on the volume of the pretreatment solution, may be 5–50 g / L or 10–20 g / L, and the content of inorganic acids, based on the volume of the pretreatment solution, may be 1–20 g / L or 2–10 g / L.

[0050] Alkylbenzene sulfonates are salts of sulfonic acid compounds having a benzene ring and an alkyl group bonded to the benzene ring and a sulfonic acid group. The alkyl group can have 10 to 16 carbon atoms. Alkylbenzene sulfonates can be sodium, potassium, or triethanolamine salts. A specific example of an alkylbenzene sulfonate is linear sodium dodecylbenzene sulfonate. The concentration of alkylbenzene sulfonates, based on the volume of the pretreatment solution, can be 0.5 to 20 g / L.

[0051] Examples of commercially available surfactants containing acetylene groups include Surfynol 104, Surfynol 440, and Surfynol 465 (product names, manufactured by Nissin Chemical Industry Co., Ltd.). The concentration of the acetylene-containing compound can be 0.1–5 g / L or 0.3–1 g / L, based on the volume of the pretreatment solution.

[0052] The pretreatment solution may contain a dispersant. The dispersant may be a polymer containing monomer units derived from maleic acid; an example of a commercially available product is MALIALIM AKM-0531 (product name, manufactured by NOF CORPORATION). The content of the dispersant, based on the volume of the pretreatment solution, may be 0.1–5 g / L or 0.3–1 g / L.

[0053] The resist layer 3 and the pretreatment solution are selected such that the mass change rate of the resist layer 3 when immersed in the pretreatment solution before exposure and development is -2.0% by mass or more. The mass change rate is a value calculated using the following formula.

[0054] Mass change rate (mass%) = {(W1-W0) / W0} × 100

[0055] W0 represents the mass of the resist layer 3 before immersion in the pretreatment solution, and W1 represents the mass of the resist layer 3 after immersing the laminate containing the resist layer 3 and a single-sided copper foil covering the resist layer 3 in the pretreatment solution at the pretreatment temperature for 30 minutes. This mass change rate reflects the balance between the amount of components dissolved from the resist layer 3 into the pretreatment solution and the amount of pretreatment solution absorbed by the resist layer 3 during immersion in the pretreatment solution. According to the inventors, when the combination of the resist layer 3 and the pretreatment solution has a mass change rate of -2.0% by mass or more, the formation of fine black portions in the copper plating layer 22 can be significantly suppressed. From the same viewpoint, the mass change rate can be -1.0% by mass or more, or -0.5% by mass or more. From the viewpoint of suppressing the peeling of the wiring 2, the mass change rate can be 3.0% by mass or less. The resist layer 3 and the pretreatment solution can be selected by taking into account the solubility of each component constituting the resist layer 3 in the pretreatment solution, so that the mass change rate is within the specified range.

[0056] A copper plating layer 21 filling the opening 3A is formed on the surface of the pretreated metal layer 20 by electroplating. Then, the resist layer 3 is peeled off from the metal layer 20. The portion of the metal layer 20 exposed by the peeling of the resist layer 3 is removed using conventional methods such as etching. As a result, a wiring 2 consisting of the metal layer 20 and the metal plating layer 21 remaining on the support 1 is formed.

[0057] The electroplated layer 21 and the wiring 2 may include linear portions with a width of 5 to 20 μm. In other words, the line / space (L / S) ratio of the wiring 2 can be 5 μm / 5 μm to 20 μm / 20 μm. According to the method of the present invention, even with such fine wiring, defects such as wire peeling and detachment are almost eliminated.

[0058] The wiring substrate 10 manufactured through the above processes includes: a support 1; and wiring 2, having a metal layer 20 disposed on the support 1 and a copper plating layer 21 formed on the metal layer 20. The number of black portions observed within the copper plating layer 21 can be 8 or less per 1 μm of width parallel to the main surface of the support 1 of the wiring 2. The number of black portions mentioned here refers to the number of black portions with a maximum width of less than 0.3 μm observed by a scanning electron microscope.

[0059] Example

[0060] The present invention is not limited to the following embodiments.

[0061] 1. Materials

[0062] Pretreatment solution

[0063] As pretreatment solutions for pretreating the seed layer before electroplating, acidic pretreatment solution A (alcohol content: 0.7% by mass) and pretreatment solution B (alcohol content: 0.6% by mass) containing alcohol and pure water were prepared.

[0064] Resist film

[0065] Photosensitive resist film A and resist film B (both manufactured by Showa Denko Materials Co., Ltd.) were prepared for circuit formation. The thickness of these photosensitive resist films is 25 μm.

[0066] Changes in the quality of the resist film caused by impregnation in the pretreatment solution

[0067] Copper-clad laminates (CCLs) with a cross-section of 50 mm² and a thickness of 0.45 mm were prepared, and the mass of each CCL was measured. Using a laminator (LAMI CORPORATION INC., GK-13DX), resist film A or resist film B was laminated onto both sides of each CCL, forming a laminate containing the resist film and a single-sided integral copper foil covering the resist film. The lamination temperature was 110°C, the lamination speed was 1.4 m / min, and the lamination pressure was 0.5 MPa. The total mass of the CCLs and the resist film was measured. The initial mass W0 of the resist film (resist layer) was calculated by subtracting the mass of each CCL from the measured mass.

[0068] Next, the copper-clad laminate with the photoresist film was immersed in pretreatment solution A at 40°C, pretreatment solution B at 45°C, or pure water at 25°C for 30 minutes. The immersed copper-clad laminate and photoresist film were then dried by heating in an oven at 70°C for 30 minutes. The total mass of the dried copper-clad laminate and photoresist film was measured. The mass W1 of the immersed photoresist film (photoresist layer) in the pretreatment solution was calculated by subtracting the mass of each copper-clad laminate from the measured dried mass. The mass change rate (%) of the photoresist film (photoresist layer) caused by immersion in the pretreatment solution was calculated using the following formula.

[0069] Quality change rate (%) = {(W1-W0) / W0} × 100

[0070] 2. Wiring Formation

[0071] The wiring was formed using the combination of resist film and pretreatment solution shown in Table 1, and following the steps below.

[0072] Formation of insulating resin layer

[0073] A 50mm square, 0.45mm thick copper-clad laminate (Showa Denko Materials Co., Ltd.) and insulating material for forming the insulating resin layer (Ajinomoto Build-up Film GX-92, manufactured by Ajinomoto Fine-Techno Co., Inc.) were prepared. The insulating material has a support film, an insulating solid resin film disposed on the support film, and a protective film. The protective film was peeled off from the insulating material, and the exposed solid resin film was placed on the copper-clad laminate. The solid resin film was pressed onto the copper-clad laminate using a vacuum laminator (MVLP-500, manufactured by Meiki Co., Ltd.). The pressing conditions were: hot plate temperature 80°C, vacuum time 20 seconds, pressing time 60 seconds, air pressure below 4 kPa, and pressure 0.4 MPa. The solid resin film was then cured by heating at 180°C for 30 minutes and then at 190°C for 60 minutes in an oven, thereby forming an insulating resin layer on the copper foil of the copper-clad laminate.

[0074] Next, the laminate formed by the insulating resin layer and the copper-clad laminate was sequentially immersed in a mixed aqueous solution of 500 mL / L Swelling Securigant (manufactured by Atotech Japan) and 3 g / L NaOH at 80°C for 15 minutes, immersed in pure water at room temperature for 2 minutes, immersed in a mixed aqueous solution of 640 mL / L Compact CP (manufactured by Atotech Japan) and 40 g / L NaOH at 80°C for 20 minutes, immersed in pure water at 50°C for 2 minutes, immersed in a mixed aqueous solution of 100 mL / L Reduction Securigant (manufactured by Atotech Japan) and 50 mL / L 98% sulfuric acid at 40°C for 5 minutes, and immersed in pure water at room temperature for 1 minute. The immersion in the descaling solution roughened the surface of the insulating resin layer.

[0075] Seed layer formation

[0076] The laminate formed by the roughened insulating resin layer and the copper-clad laminate was sequentially immersed in a 50 mL / L aqueous solution of an acidic pretreatment reagent for electroless plating (manufactured by C. Uyemura & Co., Ltd., product name: MCD-PL) at 40°C for 5 minutes, immersed in pure water at 40°C for 1 minute, immersed in pure water at room temperature for 1 minute, immersed in a 10% sulfuric acid aqueous solution at room temperature for 1 minute, immersed in pure water at room temperature for 1 minute, and immersed in a pre-dip reagent (manufactured by C. Uyemura & Co., Ltd.) at 40°C for 1 minute, immersed in pure water at room temperature for 1 minute, and immersed in a pre-dip reagent (manufactured by C. Uyemura & Co., Ltd.) at 40°C for 5 minutes, immersed in pure water at 40°C for 1 minute, immersed in pure water at room temperature for 1 minute, immersed in a 10% sulfuric acid aqueous solution at room temperature for 1 minute, and immersed in a pre-dip reagent (manufactured by C. Uyemura & Co., Ltd.) at 40°C for 1 minute, immersed in pure water at room temperature for 1 minute, and immersed in a pre-dip reagent (manufactured by C. Uyemura & Co., Ltd.) at 40°C for 1 minute, immersed in pure water at room temperature for 1 minute, immersed in a 10% sulfuric acid aqueous solution at room temperature ... Product Name: MDP-2) and sulfuric acid mixed aqueous solution (MDP-2 concentration: 10 mL / L, 95% sulfuric acid: 1 mL / L) immersion at room temperature for 2 minutes, immersion in activator reagent (C. Uyemura & Co., Ltd.) at 40°C for 5 minutes, immersion in activator reagent (C. Uyemura & Co., Ltd.) mixed solution (MAT-SP) and NaOH (MAT-SP concentration: 50 mL / L, NaOH: 1.6 g / L) for 1 minute, immersion in reducing agent reagent (C. Uyemura & Co., Ltd.) for 1 minute, immersion in reducing agent reagent (C. Uyemura & Co., Ltd.) for 1 minute, immersion in reducing agent reagent (C. Uyemura & Co., Ltd.) for 1 minute, immersion in reducing agent reagent (C. Uyemura & Co., Ltd.) for 1 minute, immersion in activator reagent (C. Uyemura & Co., Ltd.) at 40°C for 5 minutes, immersion in activator reagent (C. Uyemura & Co., Ltd.) at 40°C for 1 minute, immersion in reducing agent reagent (C. Uyemura & Co., Ltd.) for 1 minute, immersion in reducing agent reagent (C. Uyemura & Co., Ltd.) for 1 minute, immersion in activator ... The following reagents were used: MRD-2-C (manufactured by C. Uyemura & Co., Ltd.), MAB-4-C (manufactured by C. Uyemura & Co., Ltd.), and MEL-4-A (manufactured by C. Uyemura & Co., Ltd.), were immersed in a mixture of MRD-2-C, MAB-4-C, and MAB-4-A (concentrations: MRD-2-C: 10 mL / L, MAB-4-C: 50 mL / L, MAB-4-A: 10 mL / L) for 3 minutes at 35°C; immersed in pure water for 1 minute; immersed in a 50 mL / L aqueous solution of an accelerator reagent (manufactured by C. Uyemura & Co., Ltd.), MEL-3A (manufactured by C. Uyemura & Co., Ltd.), and MEL-3A (manufactured by C. Uyemura & Co., Ltd.), MEL-4-C, and MEL-4-A, for 1 minute at room temperature; and immersed in an electroless plating reagent (manufactured by C. Uyemura & Co., Ltd.). The product (manufactured by emura&Co., Ltd., product names: PEA-6A, PEA-6-B-2X, PEA-6-C, PEA-6-D, PTA-6-E) was immersed in a mixture of formaldehyde (PEA-6A concentration: 100 mL / L, PEA-6-B-2X concentration: 50 mL / L, PEA-6-C concentration: 14 mL / L, PEA-6-D concentration: 15 mL / L, PEA-6-E concentration: 50 mL / L, formaldehyde concentration: 5 mL / L) at 36°C for 15 minutes, and then immersed in pure water for 1 minute. A metal layer was formed as a seed layer by electroless plating including these immersion treatments. The formed seed layer was annealed by heating in an oven at 150°C for 30 minutes. In the case of Example 2, the seed layer was formed by laminating copper foil on an insulating resin layer. The arithmetic surface roughness Ra and average height Rc of the surface of the seed layer opposite to the insulating resin layer were measured using a laser microscope (JIS B0601:2013 (ISO 4287:1997, Amd.1:2009)).

[0077] Formation of resist layer

[0078] A laminator (LAMI CORPORATION INC., GK-13DX) was used to laminate either resist film A or resist film B onto the seed layer. The lamination temperature was 110℃, the lamination speed was 1.4 m / min, and the lamination pressure was 0.5 MPa. After lamination, the layers were left to stand for 30 minutes, and then exposed to the resist film using a lithography machine (Mikasa Corporation, ML-320FSAT), a bandpass filter (Asahi Spectra Co., Ltd., HB0405), and a negative photomask. The exposure dose was 45 mJ / cm². 2 After exposure, the substrate was left to stand for 30 minutes, then the protective film of the resist was peeled off. Development was then performed using a 1.0% sodium carbonate aqueous solution, resulting in a patterned resist layer with 10 μm wide linear openings exposing the seed layer. Development was performed using an ultra-high pressure rotary developing apparatus (manufactured by Blue Ocean Technology, Ltd.), where the developer was sprayed for 100 seconds, followed by a 100-second rinse with pure water. The developing temperature was 30°C, the rotation speed was 500 rpm, the spray pressure was 0.18 MPa, the nozzle travel distance was 7.2 cm, and the nozzle speed was 10 cm / s.

[0079] Preprocessing

[0080] The laminate consisting of a seed layer, a resist layer, and a copper-clad laminate is immersed in pretreatment solution A at 40°C, pretreatment solution B at 45°C, or pure water at room temperature (25°C). Then, the laminate is sequentially immersed in pure water at 50°C for 1 minute, in pure water at 25°C for 1 minute, and in a 10% sulfuric acid aqueous solution at 25°C for 1 minute.

[0081] Electroplating

[0082] The pretreated laminate was immersed in an electrolytic plating solution and subjected to electroplating at 25°C at 10 A / dm. 2An electroplating layer was formed on the seed layer under a current density of 10 minutes. Then, the laminate containing the seed layer and the copper plating layer was immersed in pure water at room temperature for 1 minute. The electroplating solution used was a mixture of 7.3 L of an aqueous solution containing 120 g / L copper sulfate decahydrate, 220 g / L 96% sulfuric acid, 0.25 mL hydrochloric acid, 92 mL Top Lucina NSV-1 (manufactured by OKUNO CHEMICAL INDUSTRIES CO., LTD.), 11.5 mL Top Lucina NSV-2 (manufactured by OKUNO CHEMICAL INDUSTRIES CO., LTD.), and 23 mL Top Lucina NSV-3 (manufactured by OKUNO CHEMICAL INDUSTRIES CO., LTD.).

[0083] 3. Evaluation

[0084] Black part

[0085] The formed wiring was processed using a focused ion beam apparatus (Hitachi High-Tech Corporation, MI4050) to create a test piece with a cross-section exposing the area near the interface between the seed layer and the electroplated layer. Eight locations near the interface between the seed layer and the electroplated layer in the cross-section of the test piece were photographed at 50,000x magnification using a scanning electron microscope (Hitachi High-Tech Corporation, SU8200). The obtained cross-sectional images were binarized to expose only the tiny black areas existing between the electroless and electroplated layers, and the number of black areas was recorded. Figure 2 This is an example of binarizing an electron microscope image. The number of black portions per 1 μm in width along the interface direction was calculated. ImageJ image editing software was used for binarization. Table 1 shows the average number of black portions at eight observation locations.

[0086] Wiring Formation

[0087] The wiring was inspected to confirm whether any of the 10 wirings were detached or stripped.

[0088] [Table 1]

[0089]

[0090] As shown in Table 1, it was confirmed that by selecting a combination of pretreatment solution and resist film in which the mass change rate of the resist film when immersed in the pretreatment solution is -2.0% by mass or higher, the formation of black parts near the interface between the seed layer (metal layer) and the electroplated layer can be effectively suppressed.

[0091] Symbol Explanation

[0092] 1-Support body, 2-Wire connection, 3-Resist layer, 20-Metal layer, 21-Copper plating layer, 10-Wire connection substrate.

Claims

1. A method for manufacturing a wiring board, comprising the following steps: The process of forming a resist layer on a metal layer disposed on a support; The process of forming a pattern, including openings for exposing the metal layer, on the resist layer through exposure and development; A process of pretreating the surface of the metal layer exposed in the opening by contacting it with a pretreatment liquid at a specified pretreatment temperature. and The process of forming a copper plating layer on the metal layer by electrolytic plating. The resist layer and the pretreatment solution are selected such that the mass change rate of the resist layer when it is immersed in the pretreatment solution before exposure and development is -0.5% by mass or more. The mass change rate is a value calculated by the following formula, and its unit is % by mass. Rate of change in mass = {(W1-W0) / W0} × 100 W0 represents the mass of the resist layer before immersion in the pretreatment solution, and W1 represents the mass of the resist layer determined as follows: A laminate containing the resist layer and copper foil of a single-sided copper-clad laminate covering the resist layer is immersed in the pretreatment solution at the pretreatment temperature for 30 minutes; the laminate is then dried by heating at 70°C for 30 minutes; the mass of the resist layer is determined by subtracting the mass of the copper-clad laminate from the total mass of the dried laminate. The pretreatment solution is an acidic pretreatment solution containing alcohol, and the alcohol content is 0.2% to 5% by mass based on the mass of the pretreatment solution. The arithmetic surface roughness Ra of the surface of the metal layer opposite to the support is 0.20–0.30 μm. The average height Rc of the surface of the metal layer opposite to the support is 0.7 to 1.3 μm.

2. The method according to claim 1, wherein, The resist layer and the pretreatment solution are selected with a mass change rate of -0.5% or more, taking into account the solubility of each component constituting the resist layer in the pretreatment solution.

3. The method according to claim 1, wherein, The resist layer is a photosensitive resin composition, which includes an adhesive polymer, a photopolymerizable compound having olefinic unsaturated bonds, and a photopolymerization initiator.

4. The method according to claim 3, wherein, The adhesive polymer is a copolymer comprising benzyl (meth)acrylate or its derivatives, styrene or styrene derivatives, alkyl (meth)acrylate and (meth)acrylic acid as monomer units.

5. The method according to claim 1, wherein, The copper plating layer includes linear portions with a width of 5 to 20 μm.

6. The method according to claim 1, wherein, The metal layer is a layer that is deposited on the support by electroless plating.

7. A wiring board comprising: Support body; and The wiring includes a metal layer disposed on the support and a copper plating layer formed on the metal layer. The arithmetic surface roughness Ra of the surface of the copper plating side of the metal layer is 0.20–0.30 μm. The average height Rc of the surface of the copper plating side of the metal layer is 0.7–1.3 μm. The number of black portions observed using a scanning electron microscope within the copper plating layer is less than 2.8 per 1 μm of the wiring width, and the black portions have a width of less than 0.3 μm.

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