Photosensitive element and method for manufacturing wiring substrate

Abstract

The photosensitive element according to the present invention comprises a support film, a photosensitive layer, and a protective layer in this order, the protective film being a polyethylene film, and the photosensitive layer comprising a binder polymer, a photopolymerizable compound, a photopolymerization initiator, and an anthracene-based sensitizer. The anthracene-based sensitizer contains an anthracene compound having an alkoxy group having 3 or less carbon atoms bonded to the 9-position and 10-position of the anthracene ring.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a photosensitive element and a wiring substrate. Background Art

[0002] In the manufacturing process of a wiring board, a resist pattern is formed to obtain the desired wiring. When forming the resist pattern, a photosensitive element is widely used. The element comprises a support film, a layer formed on the support film using a photosensitive composition (hereinafter also referred to as a "photosensitive layer"), and a protective film laminated on the side opposite the support film of the photosensitive layer. The resist pattern can be formed by exposing and developing the photosensitive layer.

[0003] In recent years, with the miniaturization and increasing density of electronic devices, wiring boards are being required to form finer wiring than ever before. To improve the resolution of the resulting resist pattern, anthracene derivatives such as 9,10-diethoxyanthracene (DBA) are being considered as sensitizers (e.g., see Patent Document 1).

[0004] Previous technical literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2007 / 004619 Summary of the Invention

[0007] Technical issues to be solved by the invention

[0008] In order to form a resist pattern with a space width smaller than the line width, the photosensitive element is required to further improve the resolution. In addition, the photosensitive element used in the direct-drawing exposure machine is preferably highly sensitive. On the other hand, when the photosensitive element is stored, part of the components contained in the photosensitive layer is transferred to the surface of the protective film (especially the polyethylene film), and precipitation sometimes occurs. This phenomenon is also called migration. Due to the occurrence of migration, there is a concern that the metal touch roller, which is part of the equipment, may be contaminated when the photosensitive element is handled. Therefore, the photosensitive element is required to suppress precipitation to the protective film side (improve migration resistance).

[0009] An object of the present invention is to provide a photosensitive element capable of forming a resist pattern having excellent sensitivity and resolution and having excellent migration resistance, and a method for producing a wiring board using the photosensitive element.

[0010] Means for solving technical problems

[0011] The present invention relates to a method for manufacturing a photosensitive element and a wiring substrate.

[0012] [1] A photosensitive element comprising, in order, a support film, a photosensitive layer, and a protective layer, wherein the protective film is a polyethylene film, the photosensitive layer comprises a binder polymer, a photopolymerizable compound, a photopolymerization initiator, and an anthracene sensitizer, and the anthracene sensitizer comprises an anthracene compound having an alkoxy group with 3 or less carbon atoms bonded to the 9th and 10th positions of the anthracene ring.

[0013] [2] The photosensitive element according to [1] above, wherein:

[0014] The anthracene compound is at least one selected from the group consisting of 9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, and 9,10-dipropoxyanthracene.

[0015] [3] The photosensitive element according to [1] or [2] above, wherein:

[0016] The anthracene compound is 9,10-dimethoxyanthracene or 9,10-diethoxyanthracene.

[0017] [4] The photosensitive element according to any one of [1] to [3] above, wherein the content of the anthracene compound sensitizer is 0.1 to 1.5 parts by mass based on 100 parts by mass of the total amount of the binder polymer and the photopolymerizable compound.

[0018] [5] A method for manufacturing a wiring substrate, comprising:

[0019] A process of providing a photosensitive layer on a substrate using the photosensitive element described in any one of [1] to [4] above; a process of photocuring a portion of the photosensitive layer; a process of removing an uncured portion of the photosensitive layer to form a resist pattern; and a process of forming a wiring layer on a portion of the substrate where the resist pattern is not formed.

[0020] Effects of the Invention

[0021] An object of the present invention is to provide a photosensitive element capable of forming a resist pattern having excellent sensitivity and resolution and having excellent migration resistance. According to another aspect of the present invention, a method for manufacturing a wiring board using the photosensitive element can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic cross-sectional view showing a photosensitive element according to one embodiment.

[0023] Figure 2 It is a schematic diagram showing a method for manufacturing a wiring board according to one embodiment. DETAILED DESCRIPTION

[0024] Hereinafter, embodiments of the present invention will be described in detail.

[0025] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings as needed. In the following embodiments, the constituent elements (including essential steps, etc.) are not necessarily required, unless otherwise specifically indicated or clearly considered to be required in principle. The same applies to numerical values and ranges as above, and should be interpreted as not unduly limiting the present invention.

[0026] In this specification, the term "process" encompasses not only independent processes but also processes that cannot be clearly distinguished from other processes, as long as the intended effect of the process is achieved. When viewed from above, the term "layer" encompasses not only structures formed on the entire surface but also structures formed on a portion of the surface.

[0027] "Above A" in a numerical range refers to A and a range exceeding A. "Below A" in a numerical range refers to a range less than A. The numerical range represented by "to" indicates a range that includes the numerical values recorded before and after "to" as the minimum value and the maximum value, respectively. In the numerical ranges recorded in stages in this specification, the upper limit value or lower limit value of the numerical range of a certain stage can be arbitrarily combined with the upper limit value or lower limit value of the numerical range of another stage. In the numerical ranges described in this specification, the upper limit value or lower limit value of the numerical range can be replaced by the value shown in the embodiment. "A or B" only needs to include either A and B, and may also include both. Unless otherwise specified, the materials exemplified in this specification can be used alone or in combination of two or more.

[0028] In this specification, "(meth)acrylic acid" means at least one of "acrylic acid" and its corresponding "methacrylic acid". The same applies to other similar expressions such as (meth)acrylates. "(Poly)oxyethylene" refers to oxyethylene or polyoxyethylene in which two or more ethylene groups are bonded by ether bonds. "(Poly)oxypropylene" refers to oxypropylene or polyoxypropylene in which two or more propylene groups are bonded by ether bonds. "EO modified" refers to a compound having (poly)oxyethylene. "PO modified" refers to a compound having (poly)oxypropylene. "EO / PO modified" refers to a compound having (poly)oxyethylene and / or (poly)oxypropylene.

[0029] In this specification, when multiple substances corresponding to each component are present in a composition, the amount of each component in the composition represents the total amount of the multiple substances present in the composition, unless otherwise specified. In this specification, "solids" refers to the non-volatile components of a photosensitive resin composition after removing volatile substances (such as water and solvent). In other words, "solids" refers to components other than the solvent that remain after drying the photosensitive resin composition, which will be described later, and also includes components that are liquid, syrupy, or paraffinic at room temperature (25°C).

[0030] [Photosensitive element]

[0031] The photosensitive element involved in the present invention comprises a support film, a photosensitive layer and a protective layer in this order, wherein the protective film is a polyethylene film, and the photosensitive layer comprises (A) a binder polymer, (B) a photopolymerizable compound, (C) a photopolymerization initiator and (D) an anthracene-based sensitizer, wherein the anthracene-based sensitizer comprises an anthracene compound having an alkoxy group having 3 or less carbon atoms bonded to the 9th and 10th positions of the anthracene ring.

[0032] (Photosensitive layer)

[0033] The photosensitive layer is formed using a photosensitive resin composition containing component (A): a binder polymer, component (B): a photopolymerizable compound, component (C): a photopolymerization initiator, and component (D): a photosensitizer. The photosensitive resin composition according to this embodiment may further contain component (E): a polymerization inhibitor or other components as needed. Each component is described below.

[0034] (Component (A): Binder polymer)

[0035] The photosensitive resin composition contains a binder polymer as the component (A). The component (A) may have a polymerizable monomer as a monomer unit (structural unit), and can be obtained, for example, by radical polymerization of the polymerizable monomer.

[0036] Examples of the polymerizable monomer include (meth)acrylic acid, hydroxyalkyl (meth)acrylate, benzyl (meth)acrylate, styrene compounds (styrene or styrene derivatives), alkyl (meth)acrylates, tetrahydrofurfuryl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, glycidyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, and 2,2,3,3-tetrafluoropropyl (meth)acrylate. , (meth)acrylamide (diacetone (meth)acrylamide, etc.), (meth)acrylonitrile, ethers of vinyl alcohol (vinyl n-butyl ether, etc.), α-bromo(meth)acrylic acid, α-chloro(meth)acrylic acid, β-furyl(meth)acrylic acid, β-styryl(meth)acrylic acid, maleic acid, maleic anhydride, maleic acid monoesters (monomethyl maleate, monoethyl maleate, monoisopropyl maleate, etc.), fumaric acid, cinnamic acid, α-cyanocinnamic acid, itaconic acid, crotonic acid, and propiolic acid.

[0037] From the perspective of improving alkali developability, component (A) may contain (meth)acrylic acid as a monomer unit. The content of (meth)acrylic acid in component (A) may be 1% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, 23% by mass or more, or 25% by mass or less, or 50% by mass or less, 45% by mass or less, 40% by mass or less, 35% by mass or less, or 30% by mass or less, based on the total amount of monomer units constituting component (A). From these perspectives, the content of (meth)acrylic acid monomer units may be 1-50% by mass, 10-45% by mass, 15-45% by mass, 20-40% by mass, 23-35% by mass, or 25-30% by mass.

[0038] From the viewpoint of improving alkali developability, component (A) may contain a hydroxyalkyl (meth)acrylate as a monomer unit. Examples of the hydroxyalkyl (meth)acrylate include hydroxy(meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxypentyl (meth)acrylate, and hydroxyhexyl (meth)acrylate.

[0039] The content of the hydroxyalkyl (meth)acrylate in component (A) may be 0.1% by mass or more, 0.5% by mass or more, 1.0% by mass or more, 1.5% by mass or more, 2.0% by mass or more, 2.5% by mass or more, or 3.0% by mass or less, or 20% by mass or less, 15% by mass or less, 10% by mass or less, 5.0% by mass or less, 4.0% by mass or less, or 3.0% by mass or less, based on the total amount of the monomer units constituting component (A). From these viewpoints, the content of the monomer units of the hydroxyalkyl (meth)acrylate may be, for example, 0.1 to 20% by mass, 0.5 to 15% by mass, 1.0 to 10% by mass, 1.5 to 5.0% by mass, 2.0 to 4.0% by mass, or 2.5 to 3.0% by mass.

[0040] From the viewpoint of forming a resist pattern with excellent resolution, the component (A) may contain styrene or a styrene derivative as a monomer unit. Examples of the styrene derivative include vinyltoluene and α-methylstyrene.

[0041] The content of styrene or a styrene derivative in component (A) may be 30% by mass or more, 32% by mass or more, 35% by mass or more, 40% by mass or more, 45% by mass or more, 47% by mass or more, or 90% by mass or less, 85% by mass or less, 80% by mass or less, 75% by mass or less, 70% by mass or less, 65% by mass or less, 60% by mass or less, 55% by mass or less, or 50% by mass or less, based on the total amount of the monomer units constituting component (A). From these viewpoints, the content of the monomer units of the styrene compound may be, for example, 30 to 90% by mass, 32 to 80% by mass, 35 to 70% by mass, 40 to 60% by mass, 45 to 55% by mass, or 47 to 50% by mass.

[0042] From the perspective of improving the adhesion and peeling properties of the resist pattern, component (A) may contain benzyl (meth)acrylate as a monomer unit. Based on the total amount of the monomer units constituting component (A), the content of benzyl (meth)acrylate in component (A) may be 5% by mass or more, 10% by mass or more, or 15% by mass or more, or may be 40% by mass or less, 30% by mass or less, or 25% by mass or less. From these perspectives, the content of the monomer units of benzyl (meth)acrylate may be, for example, 5-40% by mass, 5-30% by mass, 5-25% by mass, 10-30% by mass, 10-25% by mass, or 15-25% by mass.

[0043] In addition to the above-mentioned monomers, component (A) may further contain structural units derived from other monomers. Other monomers may be, for example, (meth)acrylates. Examples of (meth)acrylates include alkyl (meth)acrylates, cycloalkyl (meth)acrylates, and aryl (meth)acrylates.

[0044] From the perspective of improving alkali developability and stripping properties, the other monomer is preferably an alkyl (meth)acrylate. The alkyl group of the alkyl (meth)acrylate may be, for example, a methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, or structural isomers thereof. From the perspective of further improving stripping properties, the alkyl group may be an alkyl group having 1 to 4 carbon atoms.

[0045] From the perspective of enabling suitable development, the acid value of component (A) may be 100 mgKOH / g or higher, 120 mgKOH / g or higher, 140 mgKOH / g or higher, or 150 mgKOH / g or higher. From the perspective of excellent adhesion (developer resistance) of the cured product of the photosensitive resin composition, the acid value may be 250 mgKOH / g or lower, 240 mgKOH / g or lower, or 230 mgKOH / g or lower. The acid value of component (A) can be adjusted by the content of the structural units constituting component (A) (for example, structural units derived from (meth)acrylic acid).

[0046] From the perspective of achieving excellent adhesion (developer resistance) of the cured product of the photosensitive resin composition, the weight average molecular weight (Mw) of component (A) may be 10,000 or more, 20,000 or more, 25,000 or more, or 30,000 or more. From the perspective of enabling suitable development, Mw may be 100,000 or less, 80,000 or less, 60,000 or less, 50,000 or less, or 40,000 or less. The dispersion degree (Mw / Mn) of component (A) may be, for example, 1.0 or more or 1.5 or more. From the perspective of further improving adhesion and resolution, it may be 3.0 or less or 2.5 or less.

[0047] Weight average molecular weight and dispersity can be measured, for example, by gel permeation chromatography (GPC) using a calibration curve of standard polystyrene. More specifically, the conditions described in the examples can be used. In addition, for compounds with low molecular weight, when it is difficult to measure using the above-mentioned method for measuring weight average molecular weight, other methods can also be used to measure molecular weight, and calculate its average.

[0048] From the viewpoint of excellent film formability, the content of component (A) can be 20% by mass or more, 30% by mass or more, or 40% by mass or more, based on the total solid content of the photosensitive resin composition. From the viewpoint of better sensitivity and resolution, it can be 90% by mass or less, 80% by mass or less, or 65% by mass or less.

[0049] From the viewpoint of excellent film formability, the content of component (A) relative to 100 parts by mass of the total amount of component (A) and component (B), can be 30 parts by mass or more, 35 parts by mass or more, or 40 parts by mass or more. From the viewpoint of further improving sensitivity and resolution, it can be 70 parts by mass or less, 65 parts by mass or less, or 60 parts by mass or less.

[0050] (Component (B): Photopolymerizable compound)

[0051] The photosensitive resin composition contains a photopolymerizable compound as component (B). Component (B) is a compound that polymerizes by light, and for example, may be a compound having an ethylenically unsaturated bond. Component (B) may include a polyfunctional monomer having two or more reactive groups that react via free radicals. To improve alkali developability, resolution, and post-curing peeling properties, component (B) may include bisphenol A (meth)acrylate.

[0052] Examples of bisphenol A (meth)acrylates include 2,2-bis(4-((meth)acryloyloxypolyethoxy)phenyl)propane (2,2-bis(4-((meth)acryloyloxypentaethoxy)phenyl)propane, 2,2-bis(4-((meth)acryloyloxypolypropoxy)phenyl)propane, 2,2-bis(4-((meth)acryloyloxypolybutoxy)phenyl)propane, and 2,2-bis(4-((meth)acryloyloxypolyethoxypolypropoxy)phenyl)propane. Component (B) may contain 2,2-bis(4-((meth)acryloyloxypolyethoxy)phenyl)propane (2,2-bis(4-((meth)acryloyloxypentaethoxy)phenyl)propane, etc.) from the perspective of further improving resolution and peeling properties. As 2,2-bis(4-((meth)acryloyloxypolyethoxy)phenyl)propane, a compound having 10 or more oxyethylene groups, a compound having less than 10 oxyethylene groups, or a compound having 10 or more oxyethylene groups and a compound having less than 10 oxyethylene groups may be used in combination.

[0053] From the viewpoint of further improving resolution, the content of bisphenol A (meth)acrylate may be 20% by mass or more, 30% by mass or more, or 40% by mass or more, and may be 100% by mass or less, 95% by mass or less, or 90% by mass or less, based on the total amount of component (B).

[0054] From the perspective of further improving analytical properties and flexibility, component (B) may include an α,β-unsaturated ester compound obtained by reacting an α,β-unsaturated carboxylic acid with a polyol. Examples of the α,β-unsaturated ester compound include polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polyalkylene glycol di(meth)acrylates such as EO-modified polypropylene glycol, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, PO-modified trimethylolpropane tri(meth)acrylate, EO / PO-modified trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, and tetramethylolmethane tetra(meth)acrylate.

[0055] From the viewpoint of improving sensitivity and adhesion, component (B) may contain a compound having three or more (meth)acryloyl groups. Examples of such compounds include trimethylolpropane tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, PO-modified trimethylolpropane tri(meth)acrylate, EO / PO-modified trimethylolpropane tri(meth)acrylate, EO-modified pentaerythritol tetra(meth)acrylate, EO-modified ditrimethylolpropane tetra(meth)acrylate, and EO-modified dipentaerythritol hexa(meth)acrylate.

[0056] Based on the total amount of component (B), the content of the α,β-unsaturated ester compound can be 20% by mass or more or 30% by mass or more from the viewpoint of improving flexibility, and can be 70% by mass or less or 60% by mass or less from the viewpoint of further improving resolution.

[0057] The photosensitive resin composition may contain, as the component (B), other photopolymerizable compounds other than bisphenol A (meth)acrylate and the α,β-unsaturated ester compound.

[0058] Examples of other photopolymerizable compounds include nonylphenoxy polyoxyacrylate, phthalic acid compounds, alkyl (meth)acrylates, and photopolymerizable compounds having at least one cationically polymerizable cyclic ether group in the molecule (such as oxetane compounds). From the perspective of further appropriately improving resolution, adhesion, resist pattern, and peeling properties, the other photopolymerizable compound may be at least one selected from the group consisting of nonylphenoxy polyoxyacrylate and phthalic acid compounds.

[0059] Examples of the nonylphenoxy polyoxyacrylate include nonylphenoxy trivinyloxy acrylate, nonylphenoxy tetravinyloxy acrylate, nonylphenoxy pentavinyloxy acrylate, nonylphenoxy hexavinyloxy acrylate, nonylphenoxy heptavinyloxy acrylate, nonylphenoxy octavinyloxy acrylate, nonylphenoxy nonavinyloxy acrylate, nonylphenoxy decavinyloxy acrylate, and nonylphenoxy undecvinyloxy acrylate.

[0060] Examples of the phthalic acid compound include γ-chloro-β-hydroxypropyl-β'-(meth)acryloyloxyethyl phthalate, β-hydroxyethyl-β'-(meth)acryloyloxyethyl phthalate, and β-hydroxypropyl-β'-(meth)acryloyloxyethyl phthalate.

[0061] From the viewpoint of further appropriately improving the resolution, adhesion, resist pattern and peeling characteristics, when component (B) contains other photopolymerizable compounds, the content of other photopolymerizable compounds is 1% by mass or more, 3% by mass or more, or 5% by mass or more, and can be 30% by mass or less, 25% by mass or less, or 20% by mass or less, based on the total amount of component (B).

[0062] From the viewpoint of further improving sensitivity and resolution, the content of the polyfunctional monomer may be 20 to 60 parts by mass, 30 to 55 parts by mass, or 35 to 50 parts by mass relative to 100 parts by mass of the total amount of the components (A) and (B).

[0063] (Component (C): photopolymerization initiator)

[0064] The photosensitive resin composition contains a photopolymerization initiator as the component (C). The component (C) is not particularly limited as long as it can polymerize the component (B), and can be appropriately selected from commonly used photopolymerization initiators.

[0065] Examples of the component (C) include hexaarylbiimidazole compounds; benzophenone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholino)phenyl]-1-butanone, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, 2-methyl-1-[4-(methylthio)phenyl]-2- Aromatic ketones such as morpholine-propane-1; quinones such as alkyl anthraquinone; benzoin ether compounds such as benzoin alkyl ether; benzoin compounds such as benzoin and alkyl benzoin; benzyl derivatives such as benzyl dimethyl ketal; and phosphine oxide compounds such as bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,6-dimethylbenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, and (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide.

[0066] From the perspective of suppressing the permeation of component (D) into the polyethylene film, component (C) may contain a hexaarylbisimidazole compound. The aryl group in the hexaarylbisimidazole compound may be a phenyl group, etc. The hydrogen atoms bonded to the aryl group in the hexaarylbisimidazole compound may be substituted with halogen atoms (chlorine atoms, etc.).

[0067] The hexaarylbisimidazole compound may be a 2,4,5-triarylimidazole dimer. Examples of 2,4,5-triarylimidazole dimers include 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(o-chlorophenyl)-4,5-bis-(m-methoxyphenyl)imidazole dimer, and 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer. From the perspective of further suppressing the permeation of component (D) into the polyethylene film, the hexaarylbisimidazole compound is preferably a 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, and more preferably 2,2-bis(o-chlorophenyl)-4,5-4',5'-tetraphenyl-1,2'biimidazole.

[0068] From the perspective of further suppressing the permeation of component (D) into the polyethylene film, the content of the hexaarylbiimidazole compound may be 90% by mass or more, 95% by mass or more, or 99% by mass or more, based on the total amount of component (C). Component (C) may consist solely of the hexaarylbiimidazole compound.

[0069] The content of component (C) can be 1.0 to 20 parts by mass, 2.0 to 15 parts by mass, 3.0 to 10 parts by mass, or 4.0 to 8.0 parts by mass relative to 100 parts by mass of the total amount of components (A) and (B). When the content of component (C) is within this range, it is easy to improve both photosensitivity and resolution in a well-balanced manner.

[0070] (Component (D): anthracene sensitizer)

[0071] By including an anthracene sensitizer as component (D), the photosensitive resin composition can effectively utilize the absorption wavelength of the active light used in exposure. Component (D) can include an anthracene ring and an anthracene compound having an alkoxy group having 3 or fewer carbon atoms bonded to the 9th and 10th positions of the anthracene ring.

[0072] As component (D), by using an anthracene compound having a specific structure, it is possible to suppress the migration of component (D) from the photosensitive layer to the protective film, i.e., the polyethylene film. In contrast, in the case of an anthracene compound (e.g., 9,10-diethoxyanthracene) having an alkoxy group with 4 or more carbon atoms bonded to the 9th and 10th positions of the anthracene ring, migration to the polyethylene film is likely to occur. As a reason for this, the inventors speculate that since the alkoxy group with 3 or less carbon atoms is less hydrophobic than the alkoxy group with 4 or more carbon atoms, component (D) is not easy to penetrate into the hydrophobic polyethylene film. Furthermore, by using an anthracene compound with excellent migration resistance as component (D), the amount of component (D) contained in the photosensitive layer is actually not easy to reduce, and thus the sensitivity of the photosensitive layer can be improved.

[0073] The alkoxy group having 3 or less carbon atoms may be a methoxy group, an ethoxy group, or a propoxy group. The hydrogen atoms constituting the anthracene ring may be substituted with at least one group selected from the group consisting of an alkyl group (e.g., an alkyl group having 1 to 12 carbon atoms), a halo group, a cyano group, a carboxyl group, a phenyl group, an alkoxycarbonyl group (e.g., an alkoxycarbonyl group having 2 to 6 carbon atoms), and a benzoyl group.

[0074] Examples of anthracene compounds include 9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, and 9,10-dipropoxyanthracene. Component (D) may contain at least one selected from the group consisting of 9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, and 9,10-dipropoxyanthracene, preferably 9,10-dimethoxyanthracene or 9,10-diethoxyanthracene, from the viewpoint of achieving superior migration resistance.

[0075] From the viewpoint of further improving sensitivity, adhesion and resolution, the content of component (D) is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, further preferably 0.3 parts by mass or more, and particularly preferably 0.4 parts by mass or more, relative to 100 parts by mass of the total amount of component (A) and component (B). From the viewpoint of good storage stability of the photosensitive element, the content of component (D) is preferably 1.5 parts by mass or less, more preferably 1.2 parts by mass or less, further preferably 1.0 parts by mass or less, and particularly preferably 0.8 parts by mass or less. From the above viewpoints, the content of component (D) may be 0.1 to 1.5 parts by mass, 0.2 to 1.2 parts by mass, 0.3 to 1.0 parts by mass, or 0.4 to 0.8 parts by mass.

[0076] The photosensitive resin composition according to the present embodiment contains an anthracene compound having a specific structure as the component (D), and thus can form a resist pattern having excellent resolution even without using a sensitizing aid such as a naphthalene compound in combination.

[0077] (Component (E): polymerization inhibitor)

[0078] From the perspective of suppressing polymerization of unexposed areas during resist pattern formation and further improving resolution, the photosensitive resin composition may further contain component (E): a polymerization inhibitor. Examples of polymerization inhibitors include 4-tert-butylcatechol and 4-hydroxy-2,2,6,6-tetramethylpiperidinyl-N-oxyl.

[0079] From the viewpoint of sensitivity and resolution, the content of component (E) may be 0.001 parts by mass or more, 0.005 parts by mass or more, or 0.01 parts by mass or more relative to 100 parts by mass of the total amount of component (A) and component (B). From the viewpoint of sensitivity and adhesion, the content may be 0.10 parts by mass or less, 0.08 parts by mass or less, or 0.05 parts by mass or less.

[0080] (Other ingredients)

[0081] The photosensitive resin composition may further contain one or more other ingredients other than the above-mentioned ingredients. As other ingredients, for example, hydrogen donors (bis[4-(dimethylamino)phenyl]methane, bis[4-(diethylamino)phenyl]methane, N-phenylglycine, etc.), dyes (malachite green, etc.), tribromophenylsulfone, photodevelopers (leuco crystal violet, etc.), thermal color development inhibitors, plasticizers (p-toluenesulfonamide, etc.), pigments, fillers, defoamers, flame retardants, stabilizers, adhesion-imparting agents, leveling agents, peeling accelerators, antioxidants, fragrances, imaging agents, and thermal crosslinking agents can be mentioned. The content of other ingredients can be 0.005 mass parts or more or 0.01 mass parts or less relative to 100 mass parts of the total amount of component (A) and component (B), or can be 20 mass parts or less or 10 mass parts or less.

[0082] From the viewpoint of adjusting the viscosity, the photosensitive resin composition may further contain one or more organic solvents. Examples of the organic solvent include methanol, ethanol, acetone, methyl ethyl ketone, methyl cellulose, ethyl cellulose, toluene, N,N-dimethylformamide, and propylene glycol monomethyl ether. The photosensitive resin composition can be used as a solution (hereinafter referred to as a "coating solution") having a solid content (non-volatile content) of about 30 to 60% by mass by dissolving components (A) to (D) in an organic solvent. In addition, the solid content refers to the remaining components after removing the volatile components from the solution of the photosensitive resin composition.

[0083] (Support Film)

[0084] The support film can be a polymer film having heat resistance and solvent resistance. Examples of the support film include polyester films such as polyethylene terephthalate film (PET), polybutylene terephthalate (PBT), and polyethylene 2,6-naphthalate (PEN), and polyolefin films such as polyethylene film and polypropylene film.

[0085] The haze of the support can be 0.01 to 5.0%, 0.01 to 1.5%, 0.01 to 1.0%, or 0.01 to 0.5%. The haze can be measured using a commercially available haze meter (turbidimeter) according to the method specified in JIS K7105. For example, the haze can be measured using a commercially available turbidimeter such as NDH-5000 (manufactured by NIPPON DENSHOKU INDUSTRIES Co., Ltd.).

[0086] From the perspective of easily suppressing damage to the support film when peeling it from the photosensitive layer, the thickness of the support film may be 1 μm or more, 5 μm or more, or 10 μm or more. From the perspective of facilitating appropriate exposure when exposing through the support film, the thickness of the support film may be 100 μm or less, 50 μm or less, 30 μm or less, or 20 μm or less.

[0087] (Support Film)

[0088] Compared to polymer films such as PET and polypropylene films, polyethylene films tend to be less prone to static electricity generation. Using polyethylene film as a protective film can suppress the winding of the photosensitive element and also reduces static electricity generation when the protective film is peeled off from the photosensitive layer, thus preventing damage to the photosensitive layer.

[0089] From the perspective of easily suppressing damage to the protective layer when peeling off the protective layer and laminating the photosensitive layer and the support film on the substrate, the thickness of the protective layer may be 1 μm or more, 5 μm or more, 10 μm or more, 15 μm or more, or 20 μm or more. From the perspective of easily improving productivity, the thickness may be 100 μm or less, 50 μm or less, 40 μm or less, 35 μm or less, or 30 μm or less.

[0090] Figure 1 : is a schematic cross-sectional view of a photosensitive element according to one embodiment. Figure 1 As shown, the photosensitive element 1 includes a support film 2 , a photosensitive layer 3 provided on the support film 2 , and a protective layer 4 provided on the side of the photosensitive layer 3 opposite to the support film 2 .

[0091] The photosensitive element 1 can be obtained, for example, by the following method. First, a photosensitive layer 3 is formed on a support film 2. The photosensitive layer 3 can be formed, for example, by applying a photosensitive resin composition containing an organic solvent to form a coating layer and drying the coating layer. Then, a protective layer 4 is formed on the surface of the photosensitive layer 3 opposite the support film 2.

[0092] The coating layer is formed by a known method such as roll coating, comma coating, gravure coating, air knife coating, die coating, or bar coating. The coating layer is dried, specifically, at 70 to 150° C. for about 5 to 30 minutes, so that the amount of the organic solvent remaining in the photosensitive layer 3 is, for example, 2% by mass or less.

[0093] From the perspective of facilitating coating and improving productivity, the thickness of the photosensitive layer 3 after drying (after volatilizing the organic solvent when the photosensitive resin composition contains an organic solvent) can be greater than 1 μm, greater than 5 μm, or greater than 10 μm. From the perspective of further improving adhesion and resolution, it can be less than 100 μm, less than 50 μm, less than 40 μm, or less than 30 μm.

[0094] In another embodiment, the photosensitive element may further include other layers such as a buffer layer, an adhesive layer, a light absorbing layer, and a gas barrier layer.

[0095] The photosensitive element 1 may be in the form of a sheet, or a photosensitive element roll wound onto a core. In the photosensitive element roll, the photosensitive element 1 is preferably wound so that the support film 2 is on the outside. The core may be made of, for example, polyethylene, polypropylene, polystyrene, polyvinyl chloride, or acrylonitrile-butadiene-styrene copolymer. To protect the end faces, an end face spacer may be provided on the end face of the photosensitive element roll, and to prevent edge fusion, a moisture-proof end face spacer may be provided. The photosensitive element 1 may be packaged, for example, with a black sheet having low moisture permeability.

[0096] The photosensitive element 1 can be suitably used for forming a resist pattern, and can be particularly suitably used in a method for manufacturing a wiring board to be described later.

[0097] [Method for Forming Resist Pattern]

[0098] The method for forming a resist pattern according to this embodiment includes: using the above-mentioned photosensitive element, sequentially disposing a photosensitive layer and a support film on a substrate from the substrate side (photosensitive layer formation step); exposing the photosensitive layer to active light via the support film (exposure step); and, after peeling off the support film, removing the uncured portion of the photosensitive layer from the substrate (development step). Other steps may be included as needed. A resist pattern is also referred to as a photocured pattern of a photosensitive resin composition or as a relief pattern.

[0099] (Photosensitive layer forming step)

[0100] In the photosensitive layer forming step, a photosensitive element is used to form a photosensitive layer on a substrate. The substrate is not particularly limited, but generally, a circuit forming substrate having an insulating layer and a conductive layer formed on the insulating layer, or a die pad (lead frame substrate) such as an alloy substrate can be used.

[0101] As a method for forming a photosensitive layer on a substrate, for example, after removing the protective layer, the photosensitive layer of the photosensitive element is pressed against the substrate while being heated. In this way, a laminate comprising a substrate, a photosensitive layer, and a support film can be obtained in this order.

[0102] From the viewpoint of adhesion and followability, the photosensitive layer forming step can be carried out under reduced pressure. The heating during the pressing can be carried out at a temperature of 70 to 130°C, and the pressing pressure can be 0.1 to 1.0 MPa (1 to 10 kgf / cm 2 ) pressure, and these conditions can be appropriately selected as needed. In addition, if the photosensitive layer of the photosensitive element is heated to 70-130°C, there is no need to preheat the substrate in advance. However, in order to further improve the adhesion and followability, it is also possible to preheat the substrate.

[0103] (Exposure Process)

[0104] In the exposure step, the photosensitive layer is exposed to active light via the support film, and the exposed portion irradiated with the active light is photocured to form a photocured portion (latent image).

[0105] As the exposure method, known exposure methods can be applied, for example, a method of irradiating active light in an image-like manner through a negative or positive mask pattern called an artwork (mask exposure method), an LDI (Laser Direct Imaging) exposure method, or a method of irradiating active light in an image-like manner through a lens using an image projected from a photomask (projection exposure method). Among them, the projection exposure method can also be used from the perspective of excellent resolution. That is, the photosensitive element and the like involved in this embodiment are suitable for the projection exposure method. In addition, the projection exposure method is also called an exposure method using active light with attenuated energy.

[0106] The light source for the active light rays is not particularly limited as long as it is a commonly used, known light source. For example, a carbon arc lamp, a mercury vapor arc lamp, an ultrahigh-pressure mercury lamp, a high-pressure mercury lamp, a xenon lamp, a gas laser such as an argon laser, a solid-state laser such as a YAG laser, a semiconductor laser such as a gallium nitride blue-violet laser, or the like, which effectively emits ultraviolet light, can be used. Among these, from the perspective of improving resolution and alignment in a balanced manner, a light source capable of emitting monochromatic i-ray light with an exposure wavelength of 365 nm, a light source capable of emitting monochromatic h-ray light with an exposure wavelength of 405 nm, or a light source capable of emitting active light with an exposure wavelength of a mixed iHG ray can be used. A light source capable of emitting monochromatic i-ray light with an exposure wavelength of 365 nm can also be used. As a light source capable of emitting monochromatic i-ray light with an exposure wavelength of 365 nm, for example, an ultrahigh-pressure mercury lamp can be mentioned.

[0107] (Post-exposure heat treatment process)

[0108] To improve adhesion, the resist pattern forming method according to this embodiment may include post-exposure baking (PEB) after the exposure step and before the development step. The temperature during PEB can be 50 to 100°C. A heating device such as a hot plate, a box dryer, or a heated roller can be used as the heating device.

[0109] (Development Process)

[0110] In the development step, after the support film is peeled off, the uncured portion of the photosensitive layer is removed from the substrate. Through the development step, a resist pattern formed by the photocured portion of the photosensitive layer is formed on the substrate. The development method can be wet development or dry development, with wet development being preferred.

[0111] In the case of wet development, a developer corresponding to the photosensitive resin composition can be used to carry out development by a known wet development method. Examples of wet development methods include dipping, immersion, high-pressure spraying, brushing, scrubbing, and shaking immersion. These wet development methods can be used alone or in combination of two or more.

[0112] The developer can be appropriately selected according to the structure of the photosensitive resin composition. Examples of the developer include alkaline aqueous solutions and organic solvent developers.

[0113] From the perspective of safety, stability, and good operability, an alkaline aqueous solution can be used as a developer. Examples of the base in the alkaline aqueous solution include alkali hydroxides such as lithium, sodium, or potassium hydroxides, alkali carbonates such as lithium, sodium, potassium, or ammonium carbonates or bicarbonates, alkali metal phosphates such as potassium phosphate and sodium phosphate, alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate, sodium borate, sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1,3-propanediol, 1,3-diamino-2-propanol, and morpholine.

[0114] Examples of alkaline aqueous solutions include a 0.1-5% by mass sodium carbonate dilute solution, a 0.1-5% by mass potassium carbonate dilute solution, a 0.1-5% by mass sodium hydroxide dilute solution, and a 0.1-5% by mass sodium tetraborate dilute solution. The pH of the alkaline aqueous solution used for development can be set within a range of 9 to 11, and the temperature of the alkaline aqueous solution can be adjusted according to the developability of the photosensitive layer. For example, a surfactant, a defoaming agent, and a small amount of an organic solvent to promote development can be mixed into the alkaline aqueous solution.

[0115] Examples of the organic solvent used in the alkaline aqueous solution include 3-acetol, acetone, ethyl acetate, alkoxyethanol having an alkoxy group having 1 to 4 carbon atoms, ethanol, isopropyl alcohol, butanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether.

[0116] Examples of organic solvents used in organic solvent developers include 1,1,1-trichloroethane, N-methyl-2-pyrrolidone, N,N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, and γ-butyrolactone. To prevent fire, these organic solvents can be prepared by adding water to a concentration of 1 to 20% by mass.

[0117] (Other processes)

[0118] The resist pattern forming method according to the present embodiment may include the following steps: after removing the uncured portion in the development step, heating at 60 to 250° C. or applying a heat treatment agent at 0.2 to 10 J / cm 2 The resist pattern is further cured by exposing the resist pattern to an exposure amount of .

[0119] [Method for Manufacturing Wiring Board]

[0120] The wiring substrate manufacturing method involved in this embodiment includes: a process of setting a photosensitive layer on a substrate using the above-mentioned photosensitive element; a process of photocuring a portion of the photosensitive layer; a process of removing the uncured portion of the photosensitive layer to form a resist pattern; and a process of forming a wiring layer on the portion of the above-mentioned substrate where the resist pattern is not formed.

[0121] The method for manufacturing a printed wiring board according to this embodiment includes a step of etching or plating a substrate having a resist pattern formed thereon using the resist pattern forming method described above to form a conductive pattern. Other steps, such as a resist pattern removal step, may also be included as needed. The method for manufacturing a printed wiring board according to this embodiment can be suitably used to form a conductive pattern using the resist pattern forming method described above using a photosensitive element, and is more preferably applied to methods in which a conductive pattern is formed using a plating process. Furthermore, a conductive pattern is also referred to as a circuit.

[0122] In the etching process, the conductive layer of the substrate not covered by the resist is removed by etching using a resist pattern formed on the substrate including the conductive layer as a mask, thereby forming a conductive pattern.

[0123] The etching method can be appropriately selected according to the conductor layer to be removed. Examples of etching solutions include cupric chloride solution, ferric chloride solution, alkaline etching solution, and hydrogen peroxide-based etching solution. From the perspective of a good etching factor, ferric chloride solution can be used as the etching solution.

[0124] In the plating process, copper, solder, etc. are plated on the conductive layer of the substrate not covered by the resist, using a resist pattern formed on the substrate having the conductive layer as a mask. After the plating process, the resist is removed by removing the resist pattern (described later), and the conductive layer covered by the resist is further etched to form a conductive pattern.

[0125] The plating method may be electrolytic plating or electroless plating, and electroless plating is preferred. Examples of electroless plating include copper plating such as copper sulfate plating and copper pyrophosphate plating, solder plating such as high-throw solder plating, nickel plating such as Watt bath (nickel sulfate-nickel chloride) plating and nickel sulfamate plating, and gold plating such as hard gold plating and soft gold plating.

[0126] After the etching or plating process, the resist pattern on the substrate is removed. When removing the resist pattern, for example, a stronger alkaline aqueous solution than that used in the development process can be used for stripping. Examples of strongly alkaline aqueous solutions include 1-10% by mass sodium hydroxide aqueous solutions and 1-10% by mass potassium hydroxide aqueous solutions. Of these, 1-5% by mass sodium hydroxide aqueous solutions or potassium hydroxide aqueous solutions can be used.

[0127] Examples of methods for removing the resist pattern include a dipping method and a spraying method, and these methods may be used alone or in combination.

[0128] After the plating process is performed and the resist pattern is removed, the conductive layer covered by the resist can be further etched to form a conductive pattern, thereby manufacturing the desired printed wiring board. The etching method in this case can be appropriately selected according to the conductive layer to be removed. For example, the above-mentioned etching solution can be used.

[0129] The method for manufacturing a printed wiring board according to the present embodiment is not limited to single-layer printed wiring boards, but can also be applied to the manufacture of multilayer printed wiring boards and printed wiring boards having small-diameter through-holes.

[0130] The method for manufacturing a printed wiring board according to this embodiment can be suitably used in the manufacture of high-density package substrates, especially in the manufacture of wiring boards based on a semi-additive process. Figure 2 .

[0131] exist Figure 2 In (a), a substrate (circuit forming substrate) is prepared in which a conductor layer 40 is formed on an insulating layer 50. The conductor layer 40 is, for example, a copper layer. Figure 2 In (b), the photosensitive layer 30 and the support film 20 are formed on the conductive layer 40 of the substrate through the above-mentioned photosensitive layer forming step. Figure 2 In (c), by the exposure step, the active light 80 projecting the image of the photomask is irradiated onto the photosensitive layer 30 via the support film 20, thereby forming a photocured portion on the photosensitive layer 30. Figure 2 In (d), the region other than the photocured portion formed in the exposure step is removed from the substrate by a development step, thereby forming a resist pattern 32 as the photocured portion on the substrate.

[0132] exist Figure 2 In (e), a plating process is performed using the resist pattern 32, which is a photocured portion, as a mask to form a plated layer 60 on the conductive layer 40 of the substrate that is not covered by the resist. The conductive layer 40 and the plated layer 60 may be made of the same material or different materials. If the conductive layer 40 and the plated layer 60 are made of the same material, the conductive layer 40 and the plated layer 60 may be integrated.

[0133] exist Figure 2In (f), the photocured portion, i.e., the resist pattern 32, is stripped and removed by an aqueous solution of a strong alkali. As the aqueous solution of a strong alkali, for example, a 1-10 mass % sodium hydroxide aqueous solution, a 1-10 mass % potassium hydroxide aqueous solution, etc., can be used. Then, the conductor layer 40 masked by the resist pattern 32 is removed by a flash etching process, and a conductor pattern 70 including the etched plating layer 62 and the etched conductor layer 42 is formed. The etching solution can be appropriately selected according to the type of the conductor layer 40, for example, a cupric chloride solution, a ferric chloride solution, an alkaline etching solution, a hydrogen peroxide etching solution, etc. In addition, in Figure 2 In the embodiment, the projection exposure method is described, but the resist pattern 32 can also be formed by using the mask exposure method and the LDI exposure method at the same time.

[0134] As mentioned above, although the preferred embodiment of the present invention was described, the present invention is not limited to the above embodiment at all.

[0135] Example

[0136] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0137] (Component (A): Binder polymer)

[0138] Solution (a) was prepared by mixing 27 parts by mass of methacrylic acid, 50 parts by mass of styrene, 20 parts by mass of benzyl methacrylate, 3 parts by mass of 2-hydroxyethyl methacrylate, and 0.9 parts by mass of azobisisobutyronitrile. Solution (b) was prepared by dissolving 0.5 parts by mass of azobisisobutyronitrile in 50 parts by mass of a mixed solution (x) consisting of 30 parts by mass of methylcellulosic acid and 20 parts by mass of toluene. 500 parts by mass of the mixed solution (x) (300 parts by mass of methylcellosolve and 200 parts by mass of toluene) was placed in a flask equipped with a stirrer, reflux cooler, thermometer, dropping funnel, and nitrogen inlet tube. The mixture was stirred while nitrogen was blown into the flask and heated to 80°C. Solution (a) was then added dropwise to the mixed solution in the flask at a constant drop rate over 4 hours, followed by stirring at 80°C for 2 hours. Then, the solution (b) was added dropwise to the solution in the flask at a constant rate over 10 minutes, and the solution in the flask was stirred at 80°C for 3 hours. Furthermore, the solution in the flask was heated to 90°C over 30 minutes and maintained at 90°C for 2 hours. Stirring was then stopped, and the solution was cooled to room temperature (25°C) to obtain a solution of binder polymer A1. The nonvolatile content (solids content) of the binder polymer A1 solution was 49% by mass. The weight average molecular weight (Mw) of the binder polymer A-1 was 35,000.

[0139] The weight average molecular weight was derived by measuring by gel permeation chromatography (GPC) and converting using a calibration curve of standard polystyrene. The GPC conditions are as follows.

[0140] (GPC conditions)

[0141] Pump: Hitachi L-6000 (manufactured by Hitachi, Ltd.)

[0142] Chromatographic columns: Gelpack GL-R420, Gelpack GL-R430, Gelpack GL-R440 (all manufactured by ShowaDenko Materials Co., Ltd.)

[0143] Eluent: tetrahydrofuran

[0144] Measurement temperature: 40°C

[0145] Flow rate: 2.05 mL / min

[0146] Detector: Hitachi L-3300 RI (manufactured by Hitachi, Ltd., product name)

[0147] (Photosensitive resin composition)

[0148] (Example 1)

[0149] The mixture was prepared by mixing a solution of the binder polymer A1 as the component (A) (solid content: 56 parts by mass), 44 parts by mass of EO-modified bisphenol A dimethacrylate (manufactured by Showa Denko Materials Co., Ltd., product name "FA-321M") as the component (B), 6.5 parts by mass of 2,2'-bis(o-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole (manufactured by Hampford) as the component (C), 0.65 parts by mass of 9,10-diethoxyanthracene (manufactured by Air Water Performance Chemical Inc., product name "UVS-1101") as the component (D), 0.02 parts by mass of 4-tert-butylcatechol (manufactured by DIC Corporation, product name "DIC-TBC") as the component (E), and 4-hydroxy-2,2,6,6-tetramethylpiperidinyl-N-oxyl (manufactured by ADEKA Corporation). A photosensitive resin composition was prepared by adding 0.01 parts by mass of leuco-crystal violet (manufactured by YAMADA CHEMICAL CO., LTD.) as a color developer, 0.02 parts by mass of malachite green (manufactured by OSAKA ORGANIC CHEMICAL INDUSTRY LTD.) as a dye, 0.5 parts by mass of a mixture of carboxybenzotriazole, 5-amino-1H-tetrazole, and methoxypropanol (manufactured by SANWA KASEI CORPORATION, product name "LA-7RD"), 21 parts by mass of toluene, 7 parts by mass of methanol, and 8 parts by mass of acetone as solvents.

[0150] (Example 2)

[0151] A photosensitive resin composition was prepared in the same manner as in Example 1, except that the component (D) was changed to 9,10-dipropoxyanthracene (manufactured by Air Water Performance Chemical Inc., product name: "UVS-1221").

[0152] (Comparative Example 1)

[0153] A photosensitive resin composition was prepared in the same manner as in Example 1 except that the component (D) was changed to 9,10-dibutoxyanthracene (manufactured by Air Water Performance Chemical Inc., product name: "UVS-1331").

[0154] [Photosensitive element]

[0155] A 16μm-thick polyethylene terephthalate film (FS-31, manufactured by TORAY INDUSTRIES, INC.) was prepared as a support film. A photosensitive resin composition was applied to the support film and then dried in a hot air convection dryer at 80°C and then 120°C, forming a 15μm-thick photosensitive layer. A 28μm-thick polyethylene film (NF-15A, manufactured by Tamapoly CO., LTD.) was laminated to the photosensitive layer as a protective layer, resulting in a photosensitive element comprising a support film, a photosensitive layer, and a protective layer in that order.

[0156] [evaluate]

[0157] The following evaluations were performed using the photosensitive elements of Examples and Comparative Examples. The results are shown in Table 1.

[0158] (Production of Laminated Body)

[0159] A copper sheet laminate (ShowaDenko Materials Co., Ltd., product name "MCL-E-679") made of glass epoxy material with copper foil (thickness: 35 μm) laminated on both sides was washed with water, acid-washed, and then air-dried. The copper sheet laminate was then heated to 80°C and the aforementioned photosensitive elements were laminated thereon, removing the protective film and allowing the photosensitive layer to contact the copper surface. This produced laminates consisting of the copper sheet laminate, photosensitive layer, and support film laminated in this order. Lamination was performed using a heated roller at 110°C, with a pressure of 0.4 MPa and a roller speed of 1.5 m / min.

[0160] (Minimum development time)

[0161] The laminate was cut into rectangular pieces (12.5 cm x 4 cm) and the support film was peeled off to obtain test pieces. The unexposed photosensitive resin layer in the test piece was then spray-developed using a 1.0 mass% sodium carbonate aqueous solution at 30°C and a pressure of 0.18 MPa. The minimum development time was defined as the shortest time required to visually confirm complete removal of the unexposed photosensitive resin layer.

[0162] (Sensitivity)

[0163] After placing a 41-segment ladder plate (manufactured by Showa Denko Materials Co., Ltd.) on the support film of the above-mentioned laminate, a direct-drawing exposure machine (manufactured by Via Mechanics, Ltd., product name "DE-1UH") using a blue-violet laser diode with a wavelength of 405 nm as a light source was used. The photosensitive layer was exposed through the support film at an exposure dose (irradiation energy) such that the number of remaining segments of the 41-segment ladder plate after development was 15. The exposure dose at this time (unit: mJ / cm 2 ) was used to evaluate the sensitivity. The lower the exposure, the higher the sensitivity.

[0164] (Resolution)

[0165] After placing a 41-segment ladder plate on the support film of the above-mentioned stack, a direct-drawing exposure machine ("DE-1UH") is used to draw a pattern with a line width (L) / space width (S) (hereinafter referred to as "L / S") of x / x or 3x / x (x = 1 to 20, unit: μm, 1 μm interval), and an exposure amount (irradiation energy) such that the number of remaining segments of the 41-segment ladder plate after development becomes 15 segments, and the photosensitive layer is exposed (drawn) through the support film.

[0166] After exposure, the support film was peeled from the laminate to expose the photosensitive layer. Unexposed areas were then removed by spraying a 1.0% by mass sodium carbonate aqueous solution at 30°C for twice the minimum development time. After development, resolution was evaluated based on the minimum space width in the resist pattern, where voids (unexposed areas) were removed without residue and lines (exposed areas) were formed without meandering or defects. A smaller value indicates better resolution.

[0167] (Migration resistance)

[0168] After storing the photosensitive element at 15°C for 7 days, the protective layer was peeled off. The absorption spectrum of the protective film was measured using an ultraviolet-visible spectrophotometer (Hitachi High-Tech Science Corporation, product name "Hitachi Spectrophotometer U-3310"). The measurement was performed under the following conditions: temperature: 20°C (in a clean room environment), slit width: 2nm, scan speed: 300nm / minute, sampling interval: 0.50nm, and measurement range: 500nm to 200nm. The lower the absorbance (Abs) value at 405nm of the component (D) derived from the protective film, the better the migration resistance.

[0169] [Table 1]

[0170]

[0171] Explanation of symbols

[0172] 1-photosensitive element, 2, 20-support film, 3, 30-photosensitive layer, 4-protective layer, 32-resist pattern, 40-conductive layer, 42-conductive layer after etching, 50-insulating layer, 60-plating layer, 62-plating layer after etching, 70-conductive pattern, 80-active light.

Claims

1. A photosensitive element comprising a support film, a photosensitive layer and a protective layer in sequence, wherein: The protective film is a polyethylene film, The photosensitive layer comprises a binder polymer, a photopolymerizable compound, a photopolymerization initiator and an anthracene sensitizer. The anthracene-based sensitizer includes an anthracene compound having an alkoxy group having 3 or less carbon atoms bonded to the 9th and 10th positions of the anthracene ring.

2. The photosensitive element according to claim 1, wherein The anthracene compound is at least one selected from the group consisting of 9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, and 9,10-dipropoxyanthracene.

3. The photosensitive element according to claim 1, wherein The anthracene compound is 9,10-dimethoxyanthracene or 9,10-diethoxyanthracene.

4. The photosensitive element according to claim 1, wherein The content of the anthracene-based sensitizer is 0.1 to 1.5 parts by mass relative to 100 parts by mass of the total amount of the binder polymer and the photopolymerizable compound.

5. A method for manufacturing a wiring substrate, comprising: A step of providing a photosensitive layer on a substrate using the photosensitive element according to any one of claims 1 to 4; a step of photocuring a portion of the photosensitive layer; a step of removing an uncured portion of the photosensitive layer to form a resist pattern; and a step of forming a wiring layer on a portion of the substrate where the resist pattern is not formed.

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