Method for manufacturing wiring board

Abstract

Disclosed is a method for manufacturing a wiring board, which includes: a first step for exposing and developing a resist film that is formed on a seed layer of a substrate, on which the seed layer is formed, so as to form a space part at a lower part of the resist film and to form a hole part at an upper part of the resist film; a second step for performing electrolytic plating after the first step so as to fill the space part and the hole part with a metal, thereby forming a metal pattern; a third step for removing the resist film after the second step; and a fourth step for removing the seed layer after the third step. The hole part is a hole that has an opening on the upper surface of the resist film, and the lower surface of the hole part is connected to the space part. In a cross section of the resist film in the thickness direction which passes through the hole part and the space part, the width of the space part is larger than the width of the hole part.

Description

Manufacturing method of wiring boards

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

[0002] A method for manufacturing a wiring board has been proposed (see Patent Document 1), which includes preparing a resin-coated resist consisting of a film-like solder resist and a resin film formed on one side of the solder resist, and a substrate having a conductor pattern on its surface; placing the film-like solder resist on the conductor pattern in a semi-cured state; applying pressure to the resin film to press the solder resist against the substrate and make them adhere tightly together; peeling the resin film from the solder resist; forming an opening in the solder resist to expose a part of the conductor pattern; and fully curing the solder resist.

[0003] Japanese Patent Publication No. 2014-049555

[0004] In the manufacturing method of a wiring board, when solder resist is used as the insulating film forming material and openings are formed in the solder resist to form vias (interlayer connection vias), there are constraints on the size of the openings, and there is a limit to how small they can be made. Furthermore, when forming vias by electroplating, if an attempt is made to make the vias thinner, the removal of the seed layer for electroplating may result in the removal of the sides of the seed layer beneath the via, causing the via to collapse.

[0005] The present invention has been made in view of the above circumstances, and aims to provide a method for manufacturing a wiring board capable of forming thin vias.

[0006] The inventors of the present invention conducted diligent studies to solve the aforementioned problems and, as a result, found that they could solve the aforementioned problems, and completed the present invention having the following gist.

[0007] In other words, the present invention encompasses the following aspects: [1] A method for manufacturing a wiring board, comprising: a first step of exposing and developing a resist film formed on a seed layer of a substrate on which a seed layer is formed, thereby forming a space portion below the resist film and a hole portion above the resist film; a second step of performing electroplating after the first step to fill the space portion and the hole portion with metal and form a metal pattern; a third step of removing the resist film after the second step; and a fourth step of removing the seed layer after the third step, wherein the hole portion is a hole having an opening on the upper surface of the resist film, and is connected to the space portion at the lower surface of the hole portion, and in a cross-section in the thickness direction of the resist film that passes through the hole portion and the space portion, the width of the space portion is longer than the width of the hole portion. [2] The method for manufacturing a wiring board according to [1], wherein the exposure in the first step is exposure through a halftone mask. [3] The method for manufacturing a wiring board according to [1] or [2], wherein the exposure and development in the first step are one exposure and one development. [4] The method for manufacturing a wiring substrate according to any one of [1] to [3], wherein the resist film includes a first resist film on the lower part of the resist film and a second resist film on the upper part of the resist film, and in the first step, the space portion is formed in the first resist film and the pore portion is formed in the second resist film. [5] The method for manufacturing a wiring substrate according to [4], wherein the first resist film is a positive-type resist film and the second resist film is a positive-type resist film. [6] The method for manufacturing a wiring substrate according to [5], wherein the first resist film is more sensitive than the second resist film.[7] The method for manufacturing a wiring substrate according to [5] or [6], wherein the first step includes a first prebake of pre-baking the first resist film and a second prebake of pre-baking the second resist film before exposure, wherein a portion of the first resist film reacts by the first prebake to generate a chemical structure, the chemical structure of the first resist film is decomposed by exposure, a portion of the second resist film reacts by the second prebake to generate a chemical structure, and the chemical structure of the second resist film is decomposed by exposure. [8] The method for manufacturing a wiring substrate according to any one of [1] to [7], wherein the substrate has through electrodes. [9] The method for manufacturing a wiring substrate according to [8], wherein the metal pattern and the through electrodes are electrically connected.

[10] The method for manufacturing a wiring substrate according to any one of [1] to [9], further comprising a fifth step after the fourth step of forming an insulating film covering the metal pattern, then removing a portion of the insulating film to expose the side of the metal pattern opposite to the substrate side.

[11] The method for manufacturing a wiring board according to

[10] , wherein in the fifth step, a portion of the insulating film is removed by wet etching.

[12] The method for manufacturing a wiring board according to

[10] or

[11] , wherein the insulating film comprises polyimide or a polyimide precursor.

[13] The method for manufacturing a wiring board according to any one of [1] to

[12] , wherein the material of the seed layer is copper and the material of the metal pattern is copper.

[0008] According to the present invention, it is possible to provide a method for manufacturing a wiring board capable of forming thin vias.

[0009] Figure 1A is a schematic perspective view illustrating an example of a method for manufacturing a wiring board (Part 1). Figure 1B is a schematic perspective view illustrating an example of a method for manufacturing a wiring board (Part 2). Figure 1C is a schematic perspective view illustrating an example of a method for manufacturing a wiring board (Part 3). Figure 1D is a schematic perspective view illustrating an example of a method for manufacturing a wiring board (Part 4). Figure 1E is a schematic perspective view illustrating an example of a method for manufacturing a wiring board (Part 5). Figure 1F is a schematic perspective view illustrating an example of a method for manufacturing a wiring board (Part 6). Figure 1G is a schematic perspective view illustrating an example of a method for manufacturing a wiring board (Part 7). Figure 1H is a schematic perspective view illustrating an example of a method for manufacturing a wiring board (Part 8). Figure 1I is a schematic perspective view illustrating an example of a method for manufacturing a wiring board (Part 9). Figure 1J is a schematic perspective view illustrating an example of a method for manufacturing a wiring board (Part 10). Figure 2A is a cross-sectional view taken along A-A' in Figure 1E. Figure 2B is a cross-sectional view taken along B-B' in Figure 1E.

[0010] (Method for Manufacturing a Wiring Substrate) The method for manufacturing a wiring substrate of the present invention comprises at least a first step, a second step, a third step, and a fourth step, and further includes other steps as necessary. The first step is to expose and develop a resist film formed on a seed layer of a substrate on which a seed layer has been formed, thereby forming a space portion below the resist film and a hole portion above the resist film. The second step is to perform electroplating after the first step to fill the space portion and the hole portion with metal and form a metal pattern. The third step is to remove the resist film after the second step. The fourth step is to remove the seed layer after the third step. Here, the hole portion is a hole having an opening on the upper surface of the resist film, and is connected to the space portion on the lower surface of the hole portion. In a cross-section of the resist film in the thickness direction that passes through the hole portion and the space portion, the width of the space portion is longer than the width of the hole portion. The width of the hole portion and the width of the space portion are lengths in the direction perpendicular to the thickness direction.

[0011] In the wiring substrate manufacturing method of the present invention, a resist film is exposed and developed to form a pattern, and then electroplated onto the pattern to form a metal pattern. Unlike permanent resists such as solder resist, the resist film is removed after the metal pattern is formed. Since such a resist film does not require the heat resistance and electrical properties required for insulating film formation, a resist film capable of forming a fine pattern can be used. As a result, it is possible to form a metal pattern that includes thin vias. Furthermore, in the wiring substrate manufacturing method of the present invention, in the cross-section of the resist film in the thickness direction, the width of the space is longer than the width of the hole. Here, the locations corresponding to the holes in the metal pattern become vias. The locations corresponding to the spaces in the metal pattern become bases that support the vias. Here, the width of the spaces is longer than the width of the holes. Therefore, even when the seed layer is removed, the locations corresponding to the spaces in the metal pattern become bases, preventing the thin vias from falling over.

[0012] <First Step> The first step involves exposing and developing a resist film formed on the seed layer of a substrate on which a seed layer has been formed, thereby forming a space portion at the bottom of the resist film and a pore portion at the top of the resist film.

[0013] The formed pores are openings on the upper surface of the resist film and are connected to the space on the lower surface of the pores. Furthermore, in a cross-section of the resist film in the thickness direction that passes through the pores and space, the width of the space is greater than the width of the pore. Hereinafter, such pores and space may be referred to as "desired pores and desired space."

[0014] Exposure is preferably performed via a halftone mask because it facilitates the formation of desired holes and spaces. A halftone mask is a mask having a portion that fully transmits light, a portion that partially transmits light, and a portion that does not transmit light. In this invention, the portion that fully transmits light is sometimes referred to as the fulltone portion, and the portion that partially transmits light is sometimes referred to as the halftone portion. The light transmittance of the halftone portion is, for example, 20% to 60% at a wavelength of 365 nm.

[0015] The first step may include a pre-baking process of the resist film before exposure. The pre-baking temperature is not particularly limited and may range from 50°C to 150°C. The pre-baking time is not particularly limited and may range from 0.1 minutes to 10 minutes.

[0016] <<Substrate>> The substrate is not particularly limited, but examples include insulating substrates and semiconductor substrates. Examples of insulating substrates include glass substrates, quartz substrates, sapphire substrates, and resin substrates. Examples of semiconductor substrates include silicon substrates, silicon carbide substrates, and compound semiconductor substrates. Among these, glass substrates are preferred because they can be scaled up and have a better balance of surface smoothness, thermal expansion coefficient, non-absorbent properties, and thermal conductivity compared to silicon substrates and resin substrates. The thickness of the substrate is not particularly limited, but examples include 100 μm to 800 μm. If the substrate is thin, the deflection will be large, making handling difficult. If the substrate is thick, the time required to form through holes will be longer. From these viewpoints, the thickness of the substrate is preferably 200 μm to 500 μm. The shape of the substrate is not particularly limited, but examples include circular and rectangular shapes. There are no particular restrictions on the size of the rectangular substrate, but for example, a side length of 200 mm or more is preferred, and a side length of 300 mm or more is more preferred. There are no particular restrictions on the upper limit of the side length, but for example, a side length of 1,000 mm or less, 700 mm or less, or 500 mm or less may be used.

[0017] The seed layer formed on the substrate is not particularly limited. The material of the seed layer is not particularly limited as long as it is conductive, but examples include copper, titanium, molybdenum, tungsten, tantalum, nickel, chromium, aluminum, compounds thereof (e.g., nitrides), and alloys of two or more of these. Among these, copper is preferred because it has low resistivity and can reduce wiring delay. That is, the seed layer is preferably copper foil. The thickness of the seed layer is not particularly limited, but from the viewpoint of enabling the formation of fine wiring, it is preferably 5 μm or less, more preferably 3 μm or less, and particularly preferably 1.5 μm or less. The lower limit of the thickness of the seed layer is not particularly limited, but from the viewpoint of in-plane uniformity of the seed layer, the thickness of the seed layer is preferably 0.05 μm or more, and more preferably 0.1 μm or more.

[0018] The method for forming the seed layer is not particularly limited and includes, for example, electroless plating on the substrate, attaching a metal foil to the substrate, and sputtering. An example of a method for attaching a metal foil to the substrate is transferring a metal foil supported on a support substrate onto the substrate. In this case, the substrate may have an adhesive resin layer to improve adhesion between the substrate and the metal foil. The resin contained in the adhesive resin layer is not particularly limited and includes, for example, polyimide, polyimide precursor, bismaleimide triazine resin, epoxy resin, polyphenylene sulfide resin, polyetheretherketone resin, and polyethersulfone resin. Among these, polyimide, polyimide precursor, and bismaleimide triazine resin are preferred from the viewpoint of insulation and heat resistance. The thickness of the adhesive resin layer is not particularly limited, but is preferably 5 μm to 500 μm, and more preferably 10 μm to 100 μm.

[0019] The substrate may have through-electrodes. That is, the substrate may have through-holes that penetrate the substrate in the thickness direction, and through-electrodes may be disposed within the through-holes.

[0020] The shape of the through-electrode is not particularly limited and may be cylindrical or tapered. The size of the through-electrode on the plane perpendicular to the thickness direction of the substrate can be, for example, 20 μm to 100 μm in diameter. The material of the through-electrode is not particularly limited as long as it is conductive, but examples include copper, titanium, molybdenum, tungsten, tantalum, nickel, chromium, aluminum, compounds thereof (e.g., nitrides), and alloys of two or more of these. Among these, copper is preferred because it has low resistivity and can reduce wiring delay. The number of through-electrodes on the substrate is not particularly limited.

[0021] <<Resist Film>> In the first step, there are no particular limitations on the method for forming a resist film on the seed layer, but for example, a method of coating and drying a resist composition can be used. The resist film may be a positive-type resist film or a negative-type resist film. The resist film may be a single film or a multilayer film in which multiple films are stacked.

[0022] <<<First Resist Film and Second Resist Film>>> It is preferable that the resist film includes a first resist film at the bottom and a second resist film at the top, as this facilitates the formation of desired pores and spaces. That is, it is preferable that the resist film is a laminated film including a first resist film and a second resist film. Note that "bottom of the resist film" refers to the substrate side of the laminated resist film, and "top of the resist film" refers to the side opposite to the substrate side of the laminated resist film. It is more preferable that the resist film has a two-layer structure of a first resist film and a second resist film.

[0023] If the resist film includes a first resist film at the bottom and a second resist film at the top, for example, in the first step, the space portion is formed in the first resist film and the pore portion is formed in the second resist film.

[0024] The first and second resist films are not particularly limited as long as they can form the desired pores and spaces. However, in the case of positive-type resists, it is preferable that the first resist film is more sensitive than the second resist film, since the desired pores and spaces can be easily formed by exposure through a halftone mask. In the case of negative-type resists, it is preferable that the second resist film is more sensitive than the first resist film. The first resist film being more sensitive than the second resist film means that the optimal exposure amount for the first resist film is lower than that for the second resist film, and vice versa.

[0025] The first resist film may be a positive-type resist film or a negative-type resist film. The second resist film may be a positive-type resist film or a negative-type resist film. It is more preferable that the first resist film is a positive-type resist film and the second resist film is a positive-type resist film, as this allows for the easy formation of desired holes and spaces by exposure through a halftone mask and facilitates the removal of the resist.

[0026] The thickness of the first resist film is appropriately set according to the thickness of the in-plane metal wiring layer, for example, 0.2 μm to 10 μm, and from the viewpoint of the electrical properties of the metal wiring, 0.5 μm to 5 μm is preferred. The thickness of the second resist film is appropriately set according to the thickness of the interlayer metal wiring layer, for example, 0.5 μm to 20 μm, and from the viewpoint of the electrical properties of the metal wiring, 1 μm to 10 μm is preferred.

[0027] The first step may include a first prebake, which prebakes the first resist film, and a second prebake, which prebakes the second resist film, before exposure. Preferably, the first prebake causes a portion of the first resist film, which is a positive-type resist film, to react and generate a chemical structure, and this chemical structure of the first resist film is decomposed by exposure. Preferably, the second prebake causes a portion of the second resist film, which is a positive-type resist film, to react and generate a chemical structure, and this chemical structure of the second resist film is decomposed by exposure. An example of the chemical structure is a hemiacetal structure. The first and second prebakes may be performed in a single prebake after the first and second resist films have been formed. Alternatively, the first prebake may be performed before the first and second resist films are formed, and the second prebake may be performed after the second resist film has been formed. Preferably, the first prebake is performed before the second resist film is formed. By pre-baking the first resist film before forming the second resist film, a portion of the first resist film, which is a positive-type resist film, reacts to generate a chemical structure. This prevents the first resist film from dissolving in the solvent in the resist composition when the resist composition for forming the second resist film is applied to the first resist film.

[0028] A positive-type resist composition suitable for forming a first resist film will be described. Note that the following positive-type resist composition may also be used for forming a second resist film. The positive-type resist composition contains, for example, a polymer having an active hydrogen-containing group, a vinyl ether compound, a photoacid generator, and an organic solvent. Examples of active hydrogen-containing groups include carboxyl groups and phenolic hydroxyl groups. Examples of polymers having active hydrogen-containing groups include vinyl polymers having carboxyl groups in their side chains, vinyl polymers having phenolic hydroxyl groups in their side chains, phenol novolac polymers, cresol novolac polymers, polyimides or polyimide precursors having carboxyl groups in their side chains, polyimides or polyimide precursors having phenolic hydroxyl groups in their side chains, polyester resins having carboxyl groups in their side chains, and polyester resins having phenolic hydroxyl groups in their side chains. The vinyl ether compound is a compound having two or more vinyl ether groups.

[0029] The active hydrogen-containing groups and vinyl ether groups react upon heating (e.g., pre-baking) to form a hemiacetal structure and bond together. As a result, the positive-type resist film obtained from the positive-type resist composition forms a cross-linked structure. On the other hand, the photoacid generator contained in the positive-type resist composition generates acid upon exposure. The hemiacetal structure of the positive-type resist film obtained from the positive-type resist composition is then decomposed by the acid generated upon exposure. Through this decomposition, the active hydrogen-containing groups are regenerated.

[0030] When forming a first resist film and a second resist film using such a positive-type resist composition, methods for making the first resist film more sensitive than the second resist film include, for example, adjusting the amount of active hydrogen-containing groups in the polymer having active hydrogen-containing groups, adjusting the type and amount of vinyl ether compound, and adjusting the type and content of photoacid generator.

[0031] Vinyl polymers having active hydrogen groups can be obtained, for example, by polymerization (homopolymerization or copolymerization) of radical polymerizable monomers, including radical polymerizable monomers having active hydrogen groups. Examples of radical polymerizable monomers having active hydrogen groups include radical polymerizable monomers having carboxyl groups and radical polymerizable monomers having phenolic hydroxyl groups. Examples of radical polymerizable monomers having carboxyl groups include acrylic acid, methacrylic acid, crotonic acid, mono-(2-(acryloyloxy)ethyl) phthalate, mono-(2-(methacryloyloxy)ethyl) phthalate, N-(carboxyphenyl)maleimide, N-(carboxyphenyl)methacrylamide, and N-(carboxyphenyl)acrylamide. Examples of radical polymerizable monomers having phenolic hydroxyl groups include hydroxystyrene, N-(hydroxyphenyl)acrylamide, N-(hydroxyphenyl)methacrylamide, and N-(hydroxyphenyl)maleimide.

[0032] Other radically polymerizable monomers for obtaining vinyl polymers having active hydrogen groups include, for example, acrylic acid ester compounds, methacrylic acid ester compounds, maleimide compounds, acrylonitrile, maleic anhydride, styrene compounds, and vinyl compounds. Examples of acrylic acid ester compounds include methyl acrylate, ethyl acrylate, isopropyl acrylate, benzyl acrylate, naphthyl acrylate, anthyl acrylate, anthyl methyl acrylate, phenyl acrylate, 2,2,2-trifluoroethyl acrylate, tert-butyl acrylate, cyclohexyl acrylate, isobornyl acrylate, 2-methoxyethyl acrylate, methoxytriethylene glycol acrylate, 2-ethoxyethyl acrylate, tetrahydrofurfuryl acrylate, 3-methoxybutyl acrylate, 2-methyl-2-adamantyl acrylate, 2-propyl-2-adamantyl acrylate, 8-methyl-8-tricyclodecyl acrylate, and 8-ethyl-8-tricyclodecyl acrylate. Examples of methacrylic acid ester compounds include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, benzyl methacrylate, naphthyl methacrylate, anthlyl methacrylate, anthlyl methyl methacrylate, phenyl methacrylate, 2,2,2-trifluoroethyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, 2-methoxyethyl methacrylate, methoxytriethylene glycol methacrylate, 2-ethoxyethyl methacrylate, tetrahydrofurfuryl methacrylate, 3-methoxybutyl methacrylate, 2-methyl-2-adamantyl methacrylate, 2-propyl-2-adamantyl methacrylate, 8-methyl-8-tricyclodecyl methacrylate, and 8-ethyl-8-tricyclodecyl methacrylate. Examples of vinyl compounds include methyl vinyl ether, benzyl vinyl ether, 2-hydroxyethyl vinyl ether, phenyl vinyl ether, and propyl vinyl ether.Examples of styrene compounds include styrene, methylstyrene, chlorostyrene, and bromostyrene. Examples of maleimide compounds include maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide.

[0033] Examples of vinyl ether compounds include bis(4-(vinyloxymethyl)cyclohexylmethyl)glutarate, tri(ethylene glycol)divinyl ether, divinyl adipate ester, diethylene glycol divinyl ether, tris(4-vinyloxy)butyl trimellilate, bis(4-(vinyloxy)butyl)terephthalate, bis(4-(vinyloxy)butyl isophthalate, and cyclohexanedimethanol divinyl ether.

[0034] Examples of photoacid generators include diazomethane compounds, onium salt compounds, sulfonimide compounds, disulfone compounds, sulfonic acid derivative compounds, nitrobenzyl compounds, benzointosylate compounds, iron arene complexes, halogen-containing triazine compounds, acetophenone derivative compounds, and cyano group-containing oximesulfonate compounds. Any conventionally known or conventionally used photoacid generator can be applied in the present invention without any particular limitations.

[0035] Examples of organic solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, γ Examples include butyrolactone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone.

[0036] Typically, the resist composition is not applied on top of the second resist film. Therefore, there is no need to prevent the second resist film from dissolving in the solvent in the resist composition applied on top of it. Consequently, there is little need for a portion of the second resist film to react and form a chemical structure through pre-baking. In this respect, the positive-type resist composition used to form the second resist film may be a positive-type resist composition suitably used to form the first resist film, or it may be a different resist composition from the positive-type resist composition suitably used to form the first resist film. Examples of such resist compositions include known positive-type resist compositions, such as resist compositions containing an alkali-soluble resin and a compound having a quinone diazide group, or resist compositions containing a cresol novolac polymer. Examples of alkali-soluble resins include the polymer having the aforementioned active hydrogen-containing group. Examples of compounds having a quinone diazide group include complete ester compounds, partial ester compounds, amidates, or partial amidates of aromatic (poly)hydroxy compounds with sulfonic acids having a quinone diazide group, such as naphthoquinone-1,2-diazide-5-sulfonic acid, naphthoquinone-1,2-diazide-4-sulfonic acid, and orthanthraquinone diazidosulfonic acid. Examples of resist compositions containing cresol novolac polymer include the positive-type resist compositions described in Japanese Patent Publication No. 2-55359, Japanese Patent Publication No. 2008-88197, and Japanese Patent Publication No. 9-090626.

[0037] The light used for exposure of the resist film is not particularly limited, but examples include i-line (365 nm), h-line (405 nm), g-line (436 nm), KrF excimer laser, ArF excimer laser, etc. The light used for exposure may be a laser or a non-laser. Examples of exposure light sources include low-pressure mercury lamps, high-pressure mercury lamps, and metal halide lamps. An example of the exposure dose is 25 mJ / cm². ２ ~1000mJ / cm ２ These are some examples.

[0038] After exposure and before development, post-exposure baking may be performed. By performing post-exposure baking (PEB) after exposure, the diffusibility of the acid generated by exposure can be improved, and in the case of a positive resist film, dissociation of bonds (for example, dissociation of a hemiacetal bond) can be promoted. Examples of the temperature for post-exposure baking include 50°C to 150°C. Examples of the time for post-exposure baking include 0.1 minute to 20 minutes.

[0039] Development performed after exposure is, for example, performed using a developer. Examples of the development temperature include 5°C to 50°C. Examples of the development time include 10 seconds to 300 seconds. The developer is not particularly limited as long as it can develop, and for example, it may be an organic solvent or an alkaline developer.

[0040] Examples of organic solvents include alkylene glycol monoalkyl ethers, alkylene glycol monoalkyl ether acetates, ester solvents, ketone solvents, and alcohol solvents. Examples of alkylene glycol monoalkyl ethers include propylene glycol monomethyl ether (PGME), ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monoethyl ether, and propylene glycol monopropyl ether. Examples of alkylene glycol monoalkyl ether acetates include propylene glycol monomethyl ether acetate (PGMEA), methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monoethyl ether acetate, and propylene glycol monopropyl ether acetate. Examples of ester solvents include ethyl ethoxyacetate, ethyl methoxyacetate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethyl acetate, butyl acetate, n-propyl acetate, isopropyl acetate, isobutyl acetate, ethyl lactate, and butyl lactate. Examples of ketone solvents include methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, 3-methyl-2-pentanone, 2-pentanone, 2-heptanone, and γ-butyrolactone. Examples of alcohol solvents include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, and t-butanol. Examples of alkylene glycols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, and tripropylene glycol.

[0041] As the alkaline developer, for example, aqueous solutions of alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, etc., primary amines such as ethylamine, n-propylamine, etc., secondary amines such as diethylamine, di-n-butylamine, etc., tertiary amines such as triethylamine, methyldiethylamine, etc., alcohol amines such as dimethylethanolamine, triethanolamine, etc., quaternary ammonium salts such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, choline, etc., cyclic amines such as pyrrole, piperidine, etc. can be used. Further, appropriate amounts of alcohols such as isopropyl alcohol and surfactants such as nonionic surfactants can be added to the aqueous solutions of the above alkalis and used.

[0042] The number of times of exposure and development is, for example, once each. That is, the exposure and development in the first step are one-time exposure and one-time development.

[0043] <Second step> The second step is a step of performing electrolytic plating after the first step to fill the space portion and the hole portion with metal and form a metal pattern.

[0044] The electrolytic plating is not particularly limited, and examples thereof include electrolytic nickel plating, electrolytic copper plating, electrolytic chromium plating, electrolytic gold plating, electrolytic rhodium plating, electrolytic iridium plating, etc. Among them, electrolytic copper plating is preferable because it is simple, inexpensive, and has good electrical conductivity. That is, the material of the metal pattern is preferably copper.

[0045] The formed metal pattern has a shape corresponding to the space portion and the hole portion.

[0046] The metal pattern is, for example, electrically connected to a through electrode. When the space portion is formed on the through electrode, the portion corresponding to the space portion of the formed metal pattern contacts the through electrode.

[0047] <Third Step> The third step is to remove the resist film after the second step. Methods for removing the resist film include, for example, immersing the resist film in a stripping solution or applying the stripping solution to the resist film. The resist film may be exposed to light, and if necessary, heated after exposure to increase its solubility in the stripping solution before being immersed in the stripping solution. The stripping solution may be an organic solvent or an alkaline aqueous solution. Examples of organic solvents include N-methyl-2-pyrrolidone, dimethyl sulfoxide, diazabicycloundecene, diazabicyclononene, and 1,4-diazabicyclo[2.2.2]octane. Examples of alkaline aqueous solutions include aqueous solutions containing the alkalis mentioned in the description of the alkaline developer. Examples of stripping temperatures include 5°C to 50°C. Examples of stripping times include 10 seconds to 300 seconds.

[0048] <Fourth Step> The fourth step is to remove the seed layer after the third step. Examples of methods for removing the seed layer include dry etching and wet etching, but wet etching is preferred due to its simplicity. Examples of etching solutions used in wet etching include H ２ SO ４ (Sulfuric acid) and H ２ O ２ A mixed solution of (hydrogen peroxide) is one example.

[0049] In the seed layer removal process, the seed layer beneath a portion of the metal pattern corresponding to the space remains intact. However, in the seed layer removal process, the sides of the seed layer beneath a portion of the metal pattern corresponding to the space are removed to some extent. In such cases, unlike the present invention, if thin vias are formed directly on the seed layer, the removal of some of the sides of the seed layer makes the thin vias prone to tipping over. On the other hand, in the present invention, even if the sides of the seed layer beneath a portion of the metal pattern corresponding to the space are removed to some extent, the width of the space is greater than the width of the hole, so the portion of the metal pattern corresponding to the space acts as a base, preventing the thin vias from tipping over.

[0050] <Step 5> The method for manufacturing a wiring board according to the present invention may include a fifth step. The fifth step is a step of forming an insulating film covering the metal pattern after the fourth step, and then removing a part of the insulating film to expose the surface of the metal pattern on the side opposite to the substrate side.

[0051] The resin contained in the insulating film is not particularly limited, and examples thereof include polyimide, polyimide precursor, bismaleimide triazine resin, epoxy resin, polyphenylene sulfide resin, polyether ether ketone resin, polyether sulfone resin, and the like.

[0052] The method for forming the insulating film covering the metal pattern is not particularly limited, and examples thereof include a method of applying and drying a composition for forming an insulating film.

[0053] <<Composition for forming insulating film>> The composition for forming an insulating film is not particularly limited, and for example, it contains an alkali-soluble resin and a solvent, and further contains other components such as a cross-linking agent and a development rate adjuster as necessary.

[0054] <<<Alkali-soluble resin>>> The alkali-soluble resin used in the composition for forming an insulating film is not particularly limited, but polyamic acid is preferable. Examples of the polyamic acid include polyamic acids having a repeating unit represented by the following formula (1). (R １ is a tetravalent organic group, and R ２ is a divalent organic group.)

[0055] R １ is a residue obtained by removing four carboxy groups or two acid anhydride groups from a tetracarboxylic acid or a tetracarboxylic dianhydride. R ２ is a residue obtained by removing two amino groups from a diamine.

[0056] The method for obtaining this polyamic acid is not particularly limited, but generally it can be obtained by reacting and polymerizing a diamine with a tetracarboxylic acid or its derivatives, such as tetracarboxylic dianhydride or dicarboxylic acid dihalide. Alternatively, a method can usually be used in which the diamine and tetracarboxylic dianhydride (hereinafter abbreviated as acid dianhydride) are reacted and polymerized in a polar solvent such as N-methylpyrrolidone.

[0057] The diamines that can be used to obtain polyamic acid are not particularly limited, and one or more types may be used simultaneously. Specific examples include p-phenylenediamine, m-phenylenediamine, 4,4-methylene-bis(2,6-ethylaniline), 4,4'-methylene-bis(2-isopropyl-6-methylaniline), 4,4'-methylene-bis(2,6-diisopropylaniline), 2,4,6-trimethyl-1,3-phenylenediamine, 2,3,5,6-tetramethyl-1,4-phenylenediamine, o-tolidine, m-tolidine, 3,3',5,5'- Tetramethylbenzidine, bis[4-(3-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]hexafluoropropane, 4,4'-diamino-3,3'-dimethyldicyclohexylmethane, 4,4'-diaminodiphenyl ether, 3,4-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 2,2-bis(4-anily (n) Hexafluoropropane, 2,2-bis(3-anilino)hexafluoropropane, 2,2-bis(3-amino-4-toluyl)hexafluoropropane, 1,2-bis(4-aminophenoxy)ethane, 1,3-bis(4-aminophenoxy)propane, 1,4-bis(4-aminophenoxy)butane, 1,5-bis(4-aminophenoxy)pentane, 1,6-bis(4-aminophenoxy)hexane, 1,10-bis(4-aminophenoxy)decane Examples include 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 3,5-diaminobenzoic acid, 4-aminobenzoic acid-4-aminophenyl, and 4,4'-diaminobenzanilide. It is also preferable to use a siloxane-containing diamine to improve adhesion to the substrate. Examples of siloxane-containing diamines include the diamines listed below.

[0058] (In the formula, p represents an integer from 1 to 10.)

[0059] The acidic dianhydrides that can be used to obtain polyamic acids are not particularly limited, and one or more types may be used simultaneously. Specific examples of acidic dianhydrides include pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 3,3',4,4'-diphenylethertetracarboxylic acid dianhydride, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, and aromatic tetracarboxylic acid dianhydrides such as 3,3',4,4'-diphenylsulfonetetracarboxylic acid dianhydride. Also, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic acid dianhydride Examples include aqueous dianhydrides, alicyclic tetracarboxylic dianhydrides such as 2,3,5-tricarboxy-2-cyclopentaneacetic acid dianhydride, bicyclo[2.2.2]octo-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic acid dianhydride, and 3,5,6-tricarboxy-2-norbornaneacetic acid dianhydride, as well as aliphatic tetracarboxylic acid dianhydrides such as 1,2,3,4-butanetetracarboxylic acid dianhydride.

[0060] From the viewpoint of the solubility of the coating film obtained from the insulating film forming composition in alkaline developer, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1 Acid dianhydrides consisting of tetracarboxylic acids in which four carbonyl groups are not directly bonded to the aromatic ring are preferred, such as naphthalene succinic acid dianhydride, 2,3,5-tricarboxy-2-cyclopentaneacetic acid dianhydride, bicyclo[2.2.2]octo-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic acid dianhydride, and 3,5,6-tricarboxy-2-norbornaneacetic acid dianhydride, and more preferably 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride.

[0061] In the polymerization of polyamic acid, the ratio of the total number of moles of diamine to the total number of moles of acidic dianhydride is preferably 0.8 to 1.2. Similar to ordinary polycondensation reactions, the closer this molar ratio is to 1, the greater the degree of polymerization of the resulting polymer. If the degree of polymerization is too low, the strength of the film will be insufficient. Conversely, if the degree of polymerization is too high, the workability during film preparation may be poor. Therefore, in this invention, the degree of polymerization of the product is preferably such that the reduced viscosity is 0.05 to 5.0 dl / g (in N-methylpyrrolidone at a temperature of 30°C, concentration of 0.5 g / dl). Among these, a reduced viscosity of 0.2 to 2.0 dl / g is preferred. When reacting diamines with acidic dianhydrides in a polar solvent, suitable polar solvents include N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, N-vinylpyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, tetramethylurea, pyridine, dimethyl sulfone, hexamethyl sulfoxide, m-cresol, γ-butyrolactone, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monoethyl ether, and propylene glycol mono-n-propyl ether. These can be used individually or in combination. Furthermore, even solvents that do not dissolve polyamic acid may be mixed with the above solvents, provided that the polyamic acid produced by the polymerization reaction does not precipitate. The reaction temperature between the diamine and acidic dianhydride can be selected from any temperature between -20 and 150°C, preferably between -5 and 100°C. The polyamic acid obtained in this way can be used as is, or it can be precipitated and isolated in a poor solvent such as methanol, ethanol, or water and then recovered for use.

[0062] The content of alkali-soluble resin in the insulating film forming composition is not particularly limited, but is preferably 10% to 95% by mass, and more preferably 20% to 90% by mass, relative to the film constituent components. Film constituent components refer to components other than the solvent in the insulating film forming composition.

[0063] <<<Solvent>>> The insulating film forming composition can be easily prepared by uniformly mixing each component and is used in solution by dissolving it in a suitable solvent. Examples of such solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone. These solvents can be used individually or in combination of two or more. Furthermore, they can be used in combination with high-boiling point solvents such as propylene glycol monobutyl ether and propylene glycol monobutyl ether acetate.

[0064] The solution of the insulating film forming composition is preferably filtered using a filter appropriately selected according to the solution being used before use. A suitable pore size for the filter is, for example, about 5 μm.

[0065] The solvent content in the insulating film forming composition is not particularly limited, but is preferably 40% to 99% by mass, more preferably 45% to 97% by mass, and particularly preferably 50% to 95% by mass.

[0066] <<<Crosslinking Agent>>> In addition to the alkali-soluble resin, specific particles, and solvent mentioned above, the insulating film forming composition of the present invention may also contain a crosslinking agent. Examples of crosslinking agents include epoxy compounds. Such compounds are not particularly limited as long as they are compounds having epoxy groups. For example, examples of compounds having at least two epoxy groups include tris(2,3-epoxypropyl) isocyanurate, 1,4-butanediol diglycidyl ether, 1,2-epoxy-4-(epoxyethyl)cyclohexane, glycerol triglycidyl ether, diethylene glycol diglycidyl ether, 2,6-diglycidylphenyl glycidyl ether, 1,1,3-tris[p-(2,3-epoxypropoxy)phenyl]propane, 1,2-cyclohexanedicarboxylic acid diglycidyl ester, 4,4'-methylenebis(N,N-diglycidylaniline), 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, trimethylolethane triglycidyl ether, bisphenol-A-diglycidyl ether, and pentaerythritol polyglycidyl ether. Furthermore, polymers having epoxy groups can be used as compounds having at least two epoxy groups. Such polymers are not particularly limited as long as they are polymers having epoxy groups. Such polymers can be produced by addition polymerization using addition polymerizable monomers having epoxy groups, or by reaction of a polymer compound having hydroxyl groups with an epoxy group compound such as epichlorohydrin or glycidyl tosylate. Examples include addition polymerization polymers such as polyglycidyl methacrylate, copolymers of glycidyl methacrylate and ethyl methacrylate, copolymers of glycidyl methacrylate, styrene and 2-hydroxyethyl methacrylate, and poly(3,4-epoxycyclohexylmethyl methacrylate), as well as condensation polymerization polymers such as epoxy novolac. The weight-average molecular weight of such polymers is, for example, 300 to 200,000.

[0067] Furthermore, as compounds having at least two epoxy groups, for example, ELM434 and ELM434L (manufactured by Mitsui Chemicals, Inc.), which are epoxy resins having amino groups; Epolid GT-401, GT-403, GT-301, GT-302, Celoxide 2021, Celoxide 3000 (manufactured by Daicel Corporation), which are epoxy resins having a cyclohexene oxide structure; JER1001, 1002, 1003, 1004, 1007, 1009, 1010, and 828 (all manufactured by Mitsubishi Chemical Corporation), which are bisphenol A type epoxy resins; and JER8 07 (manufactured by Mitsubishi Chemical Corporation), etc., phenol novolac type epoxy resins such as JER152, JER154 (both manufactured by Mitsubishi Chemical Corporation), EPPN201, JER202 (both manufactured by Nippon Kayaku Co., Ltd.), etc., cresol novolac type epoxy resins such as EOCN-102, EOCN-103S, EOCN-104S, EOCN-1020, EOCN-1025, EOCN-1027 (all manufactured by Nippon Kayaku Co., Ltd.), JER180S75 (manufactured by Mitsubishi Chemical Corporation), etc., alicyclic epoxy resins such as Denacol EX-252 (manufactured by Nagase Chemtex Co., Ltd.), CY175, CY177, CY179 (all manufactured by CIBA-GEIGY A.G. Co., Ltd.), Araldite CY-182, CY-192, CY-184 (all manufactured by CIBA-GEIGY A.G.), Epiclon 200, 400 (both manufactured by Dainippon Ink & Industrial Co., Ltd.), JER871, 872 (both manufactured by Mitsubishi Chemical Corporation), ED-5661, ED-5662 (both manufactured by Celanese Coatings Co., Ltd.), etc., are used in combination with aliphatic polyglycidyl ethers such as Denacol EX-611, EX-612, EX-614, EX-62 2. Examples include EX-411, EX-512, EX-522, EX-421, EX-313, EX-314, EX-321 (manufactured by Nagase Chemtex Co., Ltd.), and triazine epoxy compounds such as TEPIC-S, TEPIC-SS, TEPIC-HS, TEPIC-VL, and TEPIC-FL (Nissan Chemical Corporation).The content of the epoxy group compound is, for example, 70 parts by mass or less, preferably 50 parts by mass or less, and more preferably 45 parts by mass or less, per 100 parts by mass of alkali-soluble resin. If the content of the epoxy group compound is greater than 70 parts by mass, sufficient solubility in the photoresist developer may not be obtained.

[0068] The content of the crosslinking agent in the insulating film forming composition is not particularly limited, but is, for example, 70% by mass or less, and preferably 50% by mass or less, relative to the alkali-soluble resin.

[0069] <<<<Development Speed ​​Adjusters>>> Development speed adjusters can be used to adjust the dissolution rate in the photoresist developer. Examples of development speed adjusters include compounds containing phenolic hydroxyl groups or carboxyl groups.

[0070] For example, compounds having an aromatic ring substituted with a phenolic hydroxyl group or a carboxyl group are preferred. For example, 1-naphthoic acid, 2-naphthoic acid, 1-naphthol, 2-naphthol, 1-aminonaphthalene, 1-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid, 3,7-dihydroxy-2-naphthoic acid, 6-bromo-2-hydroxynaphthalene, 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2 ,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 6-hydroxy-1-naphthoic acid, 1-hydroxy-2-naphthoic acid, 3-hydroxy- 2-Naphthoic acid, 6-Hydroxy-2-Naphthoic acid, 1-Bromo-2-Hydroxy-3-Naphthoic acid, 1-Bromo-4-Hydroxy-3-Naphthoic acid, 1,6-Dibromo-2-Hydroxy-3-Naphthoic acid, 3-Hydroxy-7-Methoxy-2-Naphthoic acid, 1-Amino-2-Naphthol, 1,5-Dimercaptonaphthalene, 1,4,5,8-Naphthalenetetracarboxylic acid, 3,5-Dihydroxy-2-Naphthoic acid, 1,4-Dihydroxy-2-Naphthoic acid, 2-Ethoxy-1-Naphthoic acid, 2,6-Dichloro-1 -Naphthol, 2-hydroxy-3-naphthalenecarboxylate methyl ester, 6-hydroxy-2-naphthalenecarboxylate methyl ester, 3-hydroxy-7-methoxy-2-naphthalenecarboxylate methyl ester, 3,7-dihydroxy-2-naphthalenecarboxylate methyl ester, 2,4-dibromo-1-naphthol, 1-bromo-2-naphthol, 2-naphthalenchiol, 4-methoxy-1-naphthol, 6-acetoxy-2-naphthoic acid, 1,6-dibromo-1-naphthol, 2,6-dibromo-1,5-Dihydroxynaphthalene, 1-Acetyl-2-Naphthol, 9-Anthracenecarboxylic acid, 1,4,9,10-Tetrahydroxyanthracene, and 1,8,9-Trihydroxyanthracene, Benzoic acid, 4-Methylbenzoic acid, o-Phthalic acid, m-Phthalic acid, p-Phthalic acid, 2-Methoxybenzoic acid, Isophthalic acid, Terephthalic acid, 2-Hydroxybenzoic acid, 3-Hydroxybenzoic acid, 4-Hydroxybenzoic acid Fragrant acid, 2-acetoxybenzoic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, trimesic acid, 1,4-benzenedicarboxylic acid, 2,3-dimethoxybenzoic acid, 2,4-dimethoxybenzoic acid, 2,5-dimethoxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 4-acetylbenzoic acid, pyrome Examples include littic acid, trimesic anhydride, 2-[bis-(4-hydroxyphenyl)-methyl]benzoic acid, 3,4,5-trihydroxybenzoic acid, 2-benzophenone carboxylic acid, m-phenylbenzoic acid, 3-(4'-hydroxyphenoxy)benzoic acid, 3-phenoxybenzoic acid, phenol, 1,4-dihydroxybenzene, 1,3-dihydroxybenzene, 1,2-dihydroxybenzene, 2-methylphenol, 3-methylphenol, 4-methylphenol, 1,3,5-trihydroxybenzene, 2,2-bis-4-hydroxyphenylpropane, 2-hydroxybiphenyl, 2-aminophenol, 3-aminophenol, 4-aminophenol, 2,4,6-tris(4-hydroxyphenylmethyl)-1,3-benzenediol, and 4-benzyloxyphenol, polyhydroxystyrene, etc.

[0071] Furthermore, these compounds can be used in combination with polymers or compounds having one or more reactive groups. For example, in the case of compounds having carboxyl groups or phenolic hydroxyl groups, compounds obtained by reacting them with epoxy compounds such as tris(2,3-epoxypropyl) isocyanurate, 1,4-butanediol diglycidyl ether, 1,2-epoxy-4-(epoxyethyl)cyclohexane, glycerol triglycidyl ether, diethylene glycol diglycidyl ether, 2,6-diglycidylphenyl glycidyl ether, 1,1,3-tris(p-(2,3-epoxypropoxy)phenyl)propane, 1,2-cyclohexanedicarboxylate diglycidyl ester, 4,4'-methylenebis(N,N-diglycidylaniline), 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, trimethylolethane triglycidyl ether, bisphenol-A-diglycidyl ether, and pentaerythritol polyglycidyl ether, or polymers containing structures with epoxy groups such as glycidyl methacrylate, can be used. Examples of such developing speed adjusters include compounds represented by (45) below. In formula (45), Ar is a benzene ring, naphthalene ring, or anthracene ring substituted with one or more hydroxyl groups and / or carboxyl groups, and may be substituted with a group selected from the group consisting of an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitro group, a cyano group, a thiol group having 1 to 5 carbon atoms, a phenoxy group, an acetyl group, an alkoxycarbonyl group having 1 to 5 carbon atoms, and a vinyl group.

[0072]

[0073] As a developing speed adjuster, the epoxy compounds such as tris(2,3-epoxypropyl) isocyanurate and 1,4-butanediol diglycidyl ether, and 1-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid, 3,7-dihydroxy-2-naphthoic acid, 1,2-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,3-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 6-hydroxy- Compounds obtained by reacting aromatic compounds having two or more carboxyl groups or phenolic hydroxyl groups, such as 1-naphthoic acid, 3-hydroxy-2-naphthoic acid, 1-bromo-2-hydroxy-3-naphthoic acid, 1-bromo-4-hydroxy-3-naphthoic acid, 1,6-dibromo-2-hydroxy-3-naphthoic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 3,5-dihydroxy-2-naphthoic acid, and 1,4-dihydroxy-2-naphthoic acid, terephthalic acid, isophthalic acid, p-hydroxybenzoic acid, m-hydroxybenzoic acid, o-hydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, and gallic acid, are preferred.

[0074] The content of the above-mentioned developing speed adjuster is, for example, 50 parts by mass or less, preferably 40 parts by mass or less, and more preferably 30 parts by mass or less, per 100 parts by mass of alkali-soluble resin.

[0075] The insulating film formed with the insulating film forming composition is preferably a non-photosensitive film.

[0076] Suitable coating methods for the insulating film-forming composition include, for example, a spinner or a slit coater. The insulating film-forming composition undergoes reactions within the polymer and crosslinking reactions during heating during drying, resulting in a film with an appropriate alkaline development rate. Drying is performed using heating means such as a hot plate, a hot air circulating oven, or a far-infrared heating furnace. Examples of drying temperatures include 50°C to 200°C. Examples of drying times include 0.1 minutes to 120 minutes.

[0077] The insulating film forming composition may be dried in two stages. In the case of two-stage drying, the solvent is removed in the first stage, and reactions and crosslinking reactions within the polymer are carried out in the second stage to adjust the film to have an appropriate alkaline development rate. Drying is carried out using heating means such as a hot plate, a hot air circulating oven, or a far-infrared heating furnace. For example, the drying temperature for the first stage is 50°C to 150°C. For example, the drying time for the first stage is 0.1 minutes to 10 minutes. For example, the drying temperature for the second stage is 100°C to 200°C. For example, the drying time for the second stage is 0.5 minutes to 120 minutes.

[0078] The thickness of the insulating film covering the metal pattern is not particularly limited, but for example, it is 0.5 μm to 20 μm, and preferably 1 μm to 10 μm.

[0079] The method for removing a portion of the insulating film in the fifth step is not particularly limited, but wet etching is preferred. The removal of a portion of the insulating film is sometimes called etch-back. Wet etching is performed, for example, using an etching solution. An example of an etching solution is an alkaline aqueous solution. An example of an alkaline aqueous solution is an aqueous solution containing alkalis as described in the explanation of the alkaline developer mentioned in the first step. Examples of wet etching methods include immersing the substrate in the etching solution and applying the etching solution to the insulating film. An example of an application method is spray coating. An example of the etching solution temperature is 5°C to 80°C. An example of the etching time is 0.1 minutes to 30 minutes.

[0080] The etching rate in removing a portion of the insulating film can be adjusted, for example, by the degree of hardening of the insulating film. After exposing the metal surface (the side of the metal pattern opposite to the substrate side) by removing a portion of the insulating film, the insulating film is heat-cured by post-bake. Post-bake is performed using heating means such as a hot plate, a hot air circulating oven, or a far-infrared heating furnace. Examples of post-bake temperatures include 180°C to 400°C. Examples of post-bake times include 1 minute to 300 minutes.

[0081] An example of a method for manufacturing a wiring board according to the present invention will be explained with reference to the figures. Figures 1A to 1J are schematic perspective views illustrating an example of a method for manufacturing a wiring board according to the present invention. Figure 2A is a cross-sectional view taken along line A-A' of Figure 1E. Figure 2B is a cross-sectional view taken along line B-B' of Figure 1E. In Figures 1A to 1J, parts of components and spaces (e.g., through electrodes, spaces, holes, metal patterns) present within the substrate and the resist film that are not exposed are shown with dashed lines. First, a substrate 1 on which a seed layer 2 is formed is prepared (Figure 1A). Through holes are formed in the substrate 1, and through electrodes 11a and 11b are arranged in the through holes. Through electrodes 11a and 11b are in contact with the seed layer 2. Next, a first resist film 3, which is a positive-type resist film, is formed on the seed layer 2 (Figure 1B). The first resist film 3 can be formed, for example, by coating and drying a positive-type resist composition. Next, a second resist film 4, which is a positive-type resist film, is formed on the first resist film 3 (Figure 1C). The second resist film 4 can be formed, for example, by coating and drying a positive-type resist composition. Next, the first resist film 3 and the second resist film 4 are exposed through a halftone mask 5 (Figure 1D). The halftone mask 5 has a full-tone portion 5a, a halftone portion 5b, and a light-blocking portion 5c that does not transmit light. The full-tone portion 5a is circular in shape. The halftone portion 5b is square in shape. The full-tone portion 5a is located within the halftone portion 5b. In Figure 1D, there is a gap between the halftone mask 5 and the second resist film 4, but exposure may be performed in contact with the halftone mask 5. Next, the first resist film 3 and the second resist film 4 are developed after exposure. Development removes the exposed portion of the second resist film 4 corresponding to the full-tone portion 5a, and the exposed portion of the first resist film 3 corresponding to the full-tone portion 5a and the halftone portion 5b. By doing so, holes 4a and 4b and spaces 3a and 3b are formed (Figure 1E). Hole 4a is a hole with an opening on the upper surface of the second resist film, and is connected to space 3a on the lower surface of hole 4a.The hole 4b is a hole having an opening in the upper surface of the second resist film, and is connected to the space 3b at the lower surface of the hole 4b. Also, in the cross-section in the thickness direction of the first resist film 3 and the second resist film 4 that passes through the hole 4a and the space 3a (A-A' cross-section in Figure 1E), the width of the space 3a is longer than the width of the hole 4a. In the cross-section in the thickness direction of the first resist film 3 and the second resist film 4 that passes through the hole 4b and the space 3b (B-B' cross-section in Figure 1E), the width of the space 3b is longer than the width of the hole 4b. Next, electroplating is performed to fill the space 3a and 3b and the hole 4a and 4b with metal to form a metal pattern (Figure 1F). The metal pattern has a base portion 13a corresponding to the space 3a, a wiring portion 13b corresponding to the space 3b, a column portion 14a corresponding to the hole 4a, and a column portion 14b corresponding to the hole 4b. The base portion 13a is formed directly below the column portion 14a. A through electrode 11a is also positioned directly below the base portion 13a. Therefore, the base portion 13a electrically connects the through electrode 11a and the column portion 14a formed above it. The wiring portion 13b extends from directly below the column portion 14b to directly above the through electrode 11b, which is located away from the column portion 14b, in a direction perpendicular to the thickness direction, electrically connecting the column portion 14b and the through electrode 11b. Next, the first resist film 3 and the second resist film 4 are removed (Figure 1G). The first resist film 3 and the second resist film 4 can be removed, for example, by immersing them in a stripping solution. Next, the seed layer 2 is removed (Figure 1H). The seed layer 2 can be removed, for example, by wet etching. When seed layer 2 is removed, the seed layer directly beneath the metal pattern remains, but the sides of the seed layer directly beneath the metal pattern are removed to some extent. In such cases, unlike the present invention, if thin vias (columns) are formed directly on the seed layer, the sides of the seed layer directly beneath the thin vias (columns) are removed to some extent, resulting in the thin vias (columns) becoming more prone to falling over.On the other hand, in the present invention, even if the side surface of the seed layer beneath the area corresponding to the space in the metal pattern is removed to some extent, as shown in Figures 1E, 2A, and 2B, the width of the space is longer than the width of the hole, so the area corresponding to the space in the metal pattern (base portion 13a and wiring portion 13b) acts as a base, preventing the thin vias (column portions 14a and 14b) from falling over. Next, an insulating film 6 is formed to cover the metal pattern (Figure 1I). The insulating film 6 can be formed, for example, by applying and drying an insulating film forming composition. Next, a part of the insulating film 6 is removed to expose the side of the metal pattern opposite to the substrate 1 side (Figure 1J). The removal of a part of the insulating film 6 can be done, for example, by wet etching.

[0082] 1 Substrate 2 Seed layer 3 First resist film 3a Space area 3b Space area 4 Second resist film 4a Hole area 4b Hole area 5 Halftone mask 5a Fulltone area 5b Halftone area 5c Light-shielding area 6 Insulating film 11a Through electrode 11b Through electrode 11 First support substrate 13a Base area 13b Wiring area 14a Column area 14b Column area

Claims

1. A method for manufacturing a wiring substrate, comprising: a first step of exposing and developing a resist film formed on a seed layer of a substrate on which a seed layer is formed, thereby forming a space portion below the resist film and a hole portion above the resist film; a second step of performing electroplating after the first step to fill the space portion and the hole portion with metal and form a metal pattern; a third step of removing the resist film after the second step; and a fourth step of removing the seed layer after the third step, wherein the hole portion is a hole having an opening in the upper surface of the resist film, and is connected to the space portion at the lower surface of the hole portion, and in a cross-section in the thickness direction of the resist film that passes through the hole portion and the space portion, the width of the space portion is longer than the width of the hole portion.

2. The method for manufacturing a wiring board according to claim 1, wherein the exposure in the first step is exposure through a halftone mask.

3. The method for manufacturing a wiring board according to claim 1, wherein the exposure and development in the first step consist of one exposure and one development.

4. The method for manufacturing a wiring substrate according to claim 1, wherein the resist film comprises a first resist film in the lower part of the resist film and a second resist film in the upper part of the resist film, and in the first step, the space portion is formed in the first resist film and the hole portion is formed in the second resist film.

5. The method for manufacturing a wiring substrate according to claim 4, wherein the first resist film is a positive-type resist film, and the second resist film is a positive-type resist film.

6. The method for manufacturing a wiring substrate according to claim 5, wherein the first resist film is more sensitive than the second resist film.

7. The method for manufacturing a wiring substrate according to claim 5, wherein the first step includes a first prebake of the first resist film and a second prebake of the second resist film before exposure, wherein a portion of the first resist film reacts by the first prebake to generate a chemical structure, the chemical structure of the first resist film is decomposed by exposure, a portion of the second resist film reacts by the second prebake to generate a chemical structure, and the chemical structure of the second resist film is decomposed by exposure.

8. The method for manufacturing a wiring board according to claim 1, wherein the substrate has through electrodes.

9. The method for manufacturing a wiring board according to claim 8, wherein the metal pattern and the through electrode are electrically connected.

10. A method for manufacturing a wiring board according to claim 1, further comprising a fifth step of forming an insulating film over the metal pattern after the fourth step, and then removing a portion of the insulating film to expose the side of the metal pattern opposite to the substrate side.

11. The method for manufacturing a wiring board according to claim 10, wherein in the fifth step, the removal of a portion of the insulating film is performed by wet etching.

12. The method for manufacturing a wiring substrate according to claim 10, wherein the insulating film comprises polyimide or a polyimide precursor.

13. The method for manufacturing a wiring board according to claim 1, wherein the material of the seed layer is copper and the material of the metal pattern is copper.

Images