Photosensitive element and method for manufacturing photosensitive element

Abstract

A photosensitive element according to the present disclosure is able to be produced by a method that comprises a step for forming a photosensitive layer on a support film with use of a photosensitive resin composition and a step for bonding the outer winding surface of a protective film, which has the shape of a roll, onto the photosensitive layer. This photosensitive element comprises: a support film; a photosensitive layer that is provided on one surface of the support film; and a protective film that is provided on a surface of the photosensitive layer, the surface being on the reverse side from the support film. The protective film has a weld line in a surface that is on the reverse side from the photosensitive layer.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to photosensitive elements and methods for making photosensitive elements. [Background technology]

[0002] In the field of printed wiring board manufacturing, a photosensitive element comprising a support film, a layer formed on the support film using a photosensitive resin composition (hereinafter also referred to as a "photosensitive layer"), and a protective film laminated on the surface of the photosensitive layer opposite the support film is widely used as a resist material used in etching processes, plating processes, etc.

[0003] Printed wiring boards are manufactured using a photosensitive element, for example, by the following procedure. That is, first, a photosensitive layer is laminated onto a circuit-forming substrate such as a copper-clad laminate while peeling off the protective film of the photosensitive element. Next, the photosensitive layer is exposed to light through a mask film or the like to form a photocured portion. At this time, the support film is peeled off before or after exposure. Thereafter, areas of the photosensitive layer other than the photocured portion are removed with a developer to form a resist pattern. Next, using the resist pattern as a resist, an etching process or a plating process is performed to form a conductor pattern, and finally, the photocured portion (resist pattern) of the photosensitive layer is peeled off (removed).

[0004] From the viewpoint of reducing defects in the resist pattern, the use of a support film with a specified haze value, a support film with a limited lubricant particle size, etc. has been considered (see, for example, Patent Documents 1 and 2). Also, in order to prevent the generation of bubbles when laminating the photosensitive layer onto the substrate, the use of a polypropylene film as a protective film has been considered (see, for example, Patent Document 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-13681 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-74764 [Patent Document 3] International Publication No. 2014 / 175274 Summary of the Invention [Problem to be solved by the invention]

[0006] Photosensitive elements are generally stored and used in the form of a photosensitive element roll, which is a long photosensitive element wound around a core. When the photosensitive element is wound, air may be trapped in the element.

[0007] An object of the present disclosure is to provide a photosensitive element that can prevent air entrapment during winding and a method for manufacturing the photosensitive element. [Means for solving the problem]

[0008] The photosensitive element according to the present disclosure comprises a support film, a photosensitive layer provided on one side of the support film, and a protective film provided on the photosensitive layer on the side opposite the support film, wherein the protective film has a weld line on the side opposite the photosensitive layer.

[0009] The method for manufacturing a photosensitive element according to the present disclosure includes the steps of forming a photosensitive layer on a support film using a photosensitive resin composition, and laminating the outer surface of a roll-shaped protective film onto the photosensitive layer, wherein the protective film has a weld line in the longitudinal direction of the inner surface of the roll. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to provide a photosensitive element and a method for manufacturing a photosensitive element that can prevent air entrainment during winding. [Brief explanation of the drawings]

[0011] [Figure 1]FIG. 1 is a schematic cross-sectional view illustrating a photosensitive element according to one embodiment. [Figure 2] FIG. 2 is a photograph showing an example of the appearance of the inner surface of a roll of a protective film. [Figure 3] FIG. 1 is a perspective view illustrating a photosensitive element roll according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present disclosure will be described in detail below. In this specification, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the intended function of the process is achieved. The term "layer" encompasses not only a structure that is formed over the entire surface when observed in a plan view, but also a structure that is formed only on a portion of the surface. A numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In numerical ranges described in stages in this specification, the upper or lower limit of a numerical range of a certain stage may be replaced with the upper or lower limit of a numerical range of another stage. In numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in the examples.

[0013] In this specification, "(meth)acrylic acid" means at least one of "acrylic acid" and its corresponding "methacrylic acid," and the same applies to other similar expressions such as (meth)acrylate.

[0014] In this specification, the term "solid content" refers to the non-volatile content excluding volatile substances such as water and solvents contained in the photosensitive resin composition, and refers to components that remain without volatilizing when the resin composition is dried, and also includes liquid, starch syrup-like, and wax-like components at room temperature around 25°C.

[0015] [Photosensitive element] The photosensitive element of this embodiment comprises a support film, a photosensitive layer provided on one side of the support film, and a protective film provided on the opposite side of the photosensitive layer from the support film, and the protective film has a weld line on the side opposite the photosensitive layer.

[0016] FIG. 1 is a schematic cross-sectional view showing a photosensitive element according to one embodiment. As shown in FIG. 1, the photosensitive element 1 includes a support film 10, a photosensitive layer 20, and a protective film 30. The photosensitive layer 20 has one side 20a and another side 20b facing in opposite directions in the thickness direction of the photosensitive element 1. The one side 20a is the opposite side to the support film 10. The support film 10 has one side 10a and another side 10b facing in opposite directions in the thickness direction of the photosensitive element 1. The other side 20b is the opposite side facing the one side 10a. The photosensitive layer 20 is provided on one side 10a of the support film with the other side 20b facing the one side 10a.

[0017] (protective film) The protective film 30 has one surface 30a and the other surface 30b facing in opposite directions in the thickness direction of the photosensitive element 1. The one surface 30a is located on the opposite side from the support film 10. The other surface 30b faces the one surface 20a. The protective film 30 is provided on the one surface 20a of the photosensitive layer with the other surface 30b facing the one surface 20a.

[0018] One surface 30a is the inner surface of the rolled protective film and has a weld line in the longitudinal direction. A weld line is a streak-like protrusion also known as a weld mark. A weld line is a phenomenon that visually appears as a white streak in the film flow direction and occurs in the longitudinal direction on the inner surface of the film. It is thought that the weld line is caused by the temperature difference that occurs when the extruded resin meets with the other resins when molten resin is extruded from multiple outlets inside a die to produce a film.

[0019] FIG. 2 is a photograph showing an example of the appearance of the inner surface of a protective film. As shown in FIG. 2, the protective film according to this embodiment has a weld line 32 in the longitudinal direction of the inner surface of the winding. When the photosensitive element 1 is wound around the winding core, one surface 30a of the protective film is positioned inside the photosensitive element, thereby preventing air entrapment. Furthermore, because one surface 30a is not in contact with the photosensitive layer, the shape of the weld line 32 is prevented from being transferred to the surface of the photosensitive layer when the photosensitive element is produced. This improves the appearance of the photosensitive layer and reduces defects in the resist pattern that is formed.

[0020] To further prevent air entrapment, the width of the weld line may be 45 μm or more, 50 μm or more, 55 μm or more, or 60 μm or more, and may be 300 μm or less, 200 μm or less, 150 μm or less, or 100 μm or less. The width of the weld line may be 45 to 300 μm, 50 to 200 μm, 55 to 150 μm, or 60 to 100 μm.

[0021] To further prevent air entrapment, the height of the weld line may be 0.10 μm or more, 0.12 μm or more, 0.14 μm or more, or 0.16 μm or more, and may be 3.0 μm or less, 2.8 μm or less, 2.5 μm or less, or 2.2 μm or less. The height of the weld line may be 0.10 to 3.0 μm, 0.12 to 2.8 μm, 0.14 to 2.5 μm, or 0.16 to 2.2 μm.

[0022] The thickness of the protective film 30 may be 5 to 70 μm, 10 to 60 μm, 10 to 50 μm, 15 to 40 μm, or 15 to 30 μm.

[0023] It is preferable to use a film as the protective film 30 such that the adhesive strength between the photosensitive layer 20 and the protective film 30 is smaller than the adhesive strength between the photosensitive layer 20 and the support film 10. Examples of the protective film include polyolefin films such as polyethylene and polypropylene. It is preferable to use a polyethylene film as the protective film because it is less likely to cause misalignment during winding of the photosensitive element, less likely to generate static electricity when the protective film is peeled off from the photosensitive layer, and less likely to tear the photosensitive layer.

[0024] (support film) The support film 10 has one surface 10a and the other surface 10b facing in opposite directions in the thickness direction of the photosensitive element 1. A photosensitive layer 20 is provided on one surface 10a of the support film 10. Examples of the support film include polyester films such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene-2,6-naphthalate (PEN).

[0025] The haze of the support film may be 0.01 to 5.0%, 0.01 to 1.5%, 0.01 to 1.0%, or 0.01 to 0.5%. Haze refers to a value measured using a commercially available haze meter (turbidity meter) in accordance with the method specified in JIS K7105. Haze can be measured using a commercially available turbidity meter such as NDH-5000 (trade name, manufactured by Nippon Denshoku Industries Co., Ltd.).

[0026] The thickness of the support film may be 5 to 100 μm, 5 to 70 μm, 8 to 50 μm, 10 to 30 μm, or 12 to 25 μm.

[0027] (Photosensitive layer) The photosensitive layer 20 is a layer formed from a photosensitive resin composition. The thickness of the photosensitive layer 20 may be 1 to 200 μm, 5 to 100 μm, 8 to 50 μm, or 10 to 30 μm.

[0028] There are no particular limitations on the photosensitive resin composition used to form the photosensitive layer 20. The photosensitive resin composition may contain (A) a binder polymer, (B) a photopolymerizable compound, and (C) a photopolymerization initiator.

[0029] The (A) binder polymer (hereinafter also referred to as "component (A)") can be produced, for example, by radical polymerization of a polymerizable monomer. Examples of the polymerizable monomer include styrene, styrene derivatives, acrylamides such as diacetone acrylamide, acrylonitrile, ethers of vinyl alcohol such as vinyl-n-butyl ether, (meth)acrylic acid alkyl esters, (meth)acrylic acid benzyl ester, (meth)acrylic acid tetrahydrofurfuryl ester, (meth)acrylic acid dimethylaminoethyl ester, (meth)acrylic acid diethylaminoethyl ester, (meth)acrylic acid glycidyl ester, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, (meth)acrylic acid, α-bromoacrylic acid, α-chloroacrylic acid, β-furyl(meth)acrylic acid, β-styryl(meth)acrylic acid, maleic acid, maleic anhydride, maleic acid monoesters such as monomethyl maleate, monoethyl maleate, and monoisopropyl maleate, fumaric acid, cinnamic acid, α-cyanocinnamic acid, itaconic acid, crotonic acid, and propiolic acid. The polymerizable monomers can be used alone or in combination of two or more.

[0030] From the viewpoint of alkaline developability, the component (A) may have a carboxy group. The component (A) having a carboxy group can be produced, for example, by radical polymerization of a polymerizable monomer having a carboxy group with another polymerizable monomer. The polymerizable monomer having a carboxy group may be (meth)acrylic acid or methacrylic acid.

[0031] From the standpoint of improving alkaline developability and alkaline resistance in a well-balanced manner, the content of structural units based on polymerizable monomers having a carboxy group may be 10 to 50 mass%, 15 to 40 mass%, or 20 to 35 mass%, based on the total amount of component (A). When the carboxy group content is 10 mass% or more, alkaline developability tends to be improved, and when it is 50 mass% or less, alkaline resistance tends to be excellent.

[0032] The acid value of the carboxyl group-containing component (A) may be 50 to 250 mgKOH / g, 50 to 200 mgKOH / g, or 100 to 200 mgKOH / g.

[0033] From the viewpoint of adhesion and release properties, component (A) may contain structural units based on styrene or a styrene derivative. Styrene derivatives are polymerizable compounds in which a hydrogen atom is substituted at the α-position or on an aromatic ring of styrene, such as vinyltoluene or α-methylstyrene. The content of structural units based on styrene or a styrene derivative in component (A) may be 10 to 60 mass%, 15 to 50 mass%, 35 to 50 mass%, or 40 to 50 mass%. When this content is 10 mass% or more, adhesion tends to be improved, while when it is 60 mass% or less, it is possible to prevent peeled pieces from becoming large during development, and the time required for peeling tends to be kept from increasing.

[0034] From the standpoint of improving resolution, component (A) may have structural units derived from a benzyl (meth)acrylate ester. The content of structural units derived from a benzyl (meth)acrylate ester in component (A) may be 10 to 40 mass%, 15 to 35 mass%, or 20 to 30 mass%.

[0035] From the viewpoint of improving plasticity, component (A) may have a structural unit based on a (meth)acrylic acid alkyl ester. Examples of the (meth)acrylic acid alkyl ester include (meth)acrylic acid methyl ester, (meth)acrylic acid ethyl ester, (meth)acrylic acid propyl ester, (meth)acrylic acid butyl ester, (meth)acrylic acid pentyl ester, (meth)acrylic acid hexyl ester, (meth)acrylic acid heptyl ester, (meth)acrylic acid octyl ester, (meth)acrylic acid 2-ethylhexyl ester, (meth)acrylic acid nonyl ester, (meth)acrylic acid decyl ester, (meth)acrylic acid undecyl ester, and (meth)acrylic acid dodecyl ester.

[0036] The weight-average molecular weight (Mw) of component (A) may be 10,000 to 300,000, 15,000 to 150,000, 20,000 to 100,000, or 25,000 to 80,000. When component (A) has an Mw of 10,000 or more, it tends to have excellent developer resistance, while when it is 300,000 or less, it tends to prevent development time from becoming long. Component (A) may have a polydispersity (weight-average molecular weight / number-average molecular weight) of 1.0 to 3.0, 1.0 to 2.5, or 1.0 to 2.0. A smaller polydispersity tends to improve resolution.

[0037] The weight average molecular weight and number average molecular weight in this specification are values ​​measured by gel permeation chromatography (GPC) and converted using standard polystyrene as a standard sample.

[0038] The component (A) can be used alone or in combination of two or more. When two or more types of the component (A) are used in combination, examples thereof include two or more binder polymers made of different polymerizable monomers, two or more binder polymers with different Mw, and two or more binder polymers with different dispersities.

[0039] The content of component (A) may be 30 to 80 parts by mass, 40 to 75 parts by mass, 50 to 70 parts by mass, or 50 to 60 parts by mass, relative to 100 parts by mass of the total amount of component (A) and component (B), which will be described later. When the content of component (A) is within this range, the strength of the photocured portion of the photosensitive layer is improved.

[0040] The photopolymerizable compound (B) (hereinafter also referred to as "component (B)") may be a compound having at least one ethylenically unsaturated bond in the molecule. The component (B) may be used alone or in combination of two or more.

[0041] The ethylenically unsaturated bond contained in component (B) is not particularly limited as long as it is photopolymerizable. Examples of the ethylenically unsaturated bond include α,β-unsaturated carbonyl groups such as (meth)acryloyl groups. Examples of photopolymerizable compounds having an α,β-unsaturated carbonyl group include α,β-unsaturated carboxylic acid esters of polyhydric alcohols, bisphenol-type (meth)acrylates, α,β-unsaturated carboxylic acid adducts of glycidyl group-containing compounds, (meth)acrylates having a urethane bond, nonylphenoxy polyethyleneoxy acrylate, (meth)acrylates having a phthalic acid skeleton, and (meth)acrylic acid alkyl esters.

[0042] Examples of the α,β-unsaturated carboxylic acid ester of a polyhydric alcohol include polyethylene glycol di(meth)acrylate having 2 to 14 ethylene groups, polypropylene glycol di(meth)acrylate having 2 to 14 propylene groups, polyethylene-polypropylene glycol di(meth)acrylate having 2 to 14 ethylene groups and 2 to 14 propylene groups, 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, tetramethylolmethane tetra(meth)acrylate, and (meth)acrylate compounds having a skeleton derived from dipentaerythritol or pentaerythritol. "EO modified" means that it has a block structure of ethylene oxide (EO) groups, and "PO modified" means that it has a block structure of propylene oxide (PO) groups.

[0043] From the viewpoint of improving the flexibility of the resist pattern, component (B) may contain a polyalkylene glycol di(meth)acrylate. The polyalkylene glycol di(meth)acrylate may have at least one of an EO group and a PO group, or may have both an EO group and a PO group. In a polyalkylene glycol di(meth)acrylate having both an EO group and a PO group, the EO groups and the PO groups may be present in succession in a block form or randomly. The PO group may be either an oxy-n-propylene group or an oxyisopropylene group. In the (poly)oxyisopropylene group, the secondary carbon of the propylene group may be bonded to an oxygen atom, or the primary carbon may be bonded to an oxygen atom.

[0044] Commercially available polyalkylene glycol di(meth)acrylates include, for example, FA-023M (manufactured by Showa Denko Materials Co., Ltd.), FA-024M (manufactured by Showa Denko Materials Co., Ltd.), and NK Ester HEMA-9P (manufactured by Shin-Nakamura Chemical Co., Ltd.).

[0045] From the viewpoint of improving the flexibility of the resist pattern, component (B) may contain a (meth)acrylate having a urethane bond. Examples of (meth)acrylates having a urethane bond include an addition reaction product of a (meth)acrylic monomer having an OH group at the β-position with a diisocyanate (such as isophorone diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, or 1,6-hexamethylene diisocyanate), tris((meth)acryloxytetraethylene glycol isocyanate)hexamethylene isocyanurate, EO-modified urethane di(meth)acrylate, and EO,PO-modified urethane di(meth)acrylate.

[0046] Commercially available EO-modified urethane di(meth)acrylates include, for example, "UA-11" and "UA-21EB" (manufactured by Shin-Nakamura Chemical Co., Ltd.). Commercially available EO,PO-modified urethane di(meth)acrylates include, for example, "UA-13" (manufactured by Shin-Nakamura Chemical Co., Ltd.).

[0047] From the viewpoints of facilitating the formation of a thick resist pattern and achieving a well-balanced improvement in resolution and adhesion, component (B) may contain a (meth)acrylate compound having a skeleton derived from dipentaerythritol or pentaerythritol. The (meth)acrylate compound having a skeleton derived from dipentaerythritol preferably has four or more (meth)acryloyl groups, and may be dipentaerythritol penta(meth)acrylate or dipentaerythritol hexa(meth)acrylate.

[0048] The component (B) may contain a polyfunctional (meth)acrylate compound obtained by reacting a polyhydric alcohol with an α,β-unsaturated carboxylic acid. The polyfunctional (meth)acrylate compound may have at least one of an EO group and a PO group, or may have both an EO group and a PO group. Examples of such compounds include dipentaerythritol (meth)acrylate having an EO group. Commercially available dipentaerythritol (meth)acrylate having an EO group includes, for example, DPEA-12 (manufactured by Nippon Kayaku Co., Ltd.).

[0049] From the viewpoint of improving resolution and release properties after curing, component (B) may contain a bisphenol-type (meth)acrylate, and among bisphenol-type (meth)acrylates, it may contain bisphenol A-type (meth)acrylate. Examples of bisphenol A-type (meth)acrylates include 2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane, 2,2-bis(4-((meth)acryloxypolypropoxy)phenyl)propane, 2,2-bis(4-((meth)acryloxypolybutoxy)phenyl)propane, and 2,2-bis(4-((meth)acryloxypolyethoxypolypropoxy)phenyl)propane.

[0050] Commercially available examples include 2,2-bis(4-((meth)acryloxydiethoxy)phenyl)propane, such as BPE-200 (manufactured by Shin-Nakamura Chemical Co., Ltd.), and 2,2-bis(4-(methacryloxypentaethoxy)phenyl)propane, such as BPE-500 (manufactured by Shin-Nakamura Chemical Co., Ltd.) and FA-321M (manufactured by Showa Denko Materials K.K.).

[0051] Examples of nonylphenoxy polyethyleneoxyacrylates include nonylphenoxytetraethyleneoxyacrylate, nonylphenoxypentaethyleneoxyacrylate, nonylphenoxyhexaethyleneoxyacrylate, nonylphenoxyheptaethyleneoxyacrylate, nonylphenoxyoctaethyleneoxyacrylate, nonylphenoxynonaethyleneoxyacrylate, nonylphenoxydecaethyleneoxyacrylate, and nonylphenoxyundecaethyleneoxyacrylate.

[0052] Examples of (meth)acrylates having a phthalic acid skeleton include γ-chloro-β-hydroxypropyl-β'-(meth)acryloyloxyethyl-o-phthalate, β-hydroxyethyl-β'-(meth)acryloyloxyethyl-o-phthalate, and β-hydroxypropyl-β'-(meth)acryloyloxyethyl-o-phthalate. γ-Chloro-β-hydroxypropyl-β'-methacryloyloxyethyl-o-phthalate is commercially available as FA-MECH (manufactured by Showa Denko Materials Co., Ltd.).

[0053] The (C) photopolymerization initiator (hereinafter also referred to as "component (C)") is not particularly limited as long as it can polymerize component (B), and can be appropriately selected from commonly used photopolymerization initiators. Component (C) can be used alone or in combination of two or more.

[0054] Examples of the component (C) include photopolymerization initiators such as acylphosphine oxides, oxime esters, aromatic ketones, quinones, alkylphenones, imidazoles, acridines, phenylglycine, and coumarins. To improve sensitivity and resolution in a balanced manner, the component (C) may contain an acridine-based photopolymerization initiator, a phenylglycine-based photopolymerization initiator, or an imidazole-based photopolymerization initiator.

[0055] Examples of the acridine-based photopolymerization initiator include 9-phenylacridine, 9-(p-methylphenyl)acridine, 9-(m-methylphenyl)acridine, 9-(p-chlorophenyl)acridine, 9-(m-chlorophenyl)acridine, 9-aminoacridine, 9-dimethylaminoacridine, 9-diethylaminoacridine, 9-pentylaminoacridine, 1,2-bis(9-acridinyl)ethane, 1,4-bis(9-acridinyl)butane, 1,6-bis(9-acridinyl)hexane, and 1,8-bis(9-acridinyl)octadecane. bis(9-acridinyl)alkanes such as 1,10-bis(9-acridinyl)decane, 1,12-bis(9-acridinyl)dodecane, 1,14-bis(9-acridinyl)tetradecane, 1,16-bis(9-acridinyl)hexadecane, 1,18-bis(9-acridinyl)octadecane, and 1,20-bis(9-acridinyl)eicosane; 1,3-bis(9-acridinyl)-2-oxapropane, 1,3-bis(9-acridinyl)-2-thiapropane, and 1,5-bis(9-acridinyl)-3-thiapentane.

[0056] Examples of the phenylglycine-based photopolymerization initiator include N-phenylglycine, N-methyl-N-phenylglycine, and N-ethyl-N-phenylglycine.

[0057] Examples of the hexaarylbiimidazole photopolymerization initiator include 2-(o-chlorophenyl)-4,5-diphenylbiimidazole, 2,2',5-tris-(o-chlorophenyl)-4-(3,4-dimethoxyphenyl)-4',5'-diphenylbiimidazole, 2,4-bis-(o-chlorophenyl)-5-(3,4-dimethoxyphenyl)-diphenylbiimidazole, 2,4,5-tris-(o-chlorophenyl)-diphenylbiimidazole, 2-(o-chlorophenyl)-bis-4,5-(3,4-dimethoxyphenyl)-biimidazole, Examples include 2,2'-bis-(2-fluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,3-difluoromethylphenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,4-difluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, and 2,2'-bis-(2,5-difluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole.

[0058] The amount of component (C) may be 0.1 to 10 parts by mass, 1 to 5 parts by mass, or 2 to 4.5 parts by mass, based on 100 parts by mass of the total amount of components (A) and (B). When the amount of component (C) is 0.1 part by mass or more, photosensitivity, resolution, and adhesion tend to be improved, while when it is 10 parts by mass or less, resist pattern formability tends to be better.

[0059] The photosensitive resin composition according to this embodiment may further contain a (D) photosensitizer (hereinafter also referred to as "component (D)"). By containing component (D), it is possible to effectively utilize the absorption wavelength of the actinic rays used for exposure. The component (D) may be used alone or in combination of two or more.

[0060] Examples of component (D) include dialkylaminobenzophenone compounds, pyrazoline compounds, anthracene compounds, coumarin compounds, xanthone compounds, thioxanthone compounds, oxazole compounds, benzoxazole compounds, thiazole compounds, benzothiazole compounds, triazole compounds, stilbene compounds, triazine compounds, thiophene compounds, naphthalimide compounds, triarylamine compounds, and aminoacridine compounds. Component (D) may contain a pyrazoline compound or an anthracene compound to further improve resolution.

[0061] Examples of the pyrazoline compound include 1-(4-methoxyphenyl)-3-styryl-5-phenyl-pyrazoline, 1-phenyl-3-(4-methoxystyryl)-5-(4-methoxyphenyl)-pyrazoline, 1,5-bis-(4-methoxyphenyl)-3-(4-methoxystyryl)-pyrazoline, 1-(4-isopropylphenyl)-3-styryl-5-phenyl-pyrazoline, 1-phenyl-3-(4-isopropylstyryl)-5-(4-isopropylphenyl)-pyrazoline, 1,5-bis-(4-isopropylphenyl)-3-(4- 1-(4-tert-butyl-phenyl)-3-(4-isopropylstyryl)-pyrazoline, 1-(4-methoxyphenyl)-3-(4-tert-butyl-styryl)-5-(4-tert-butyl-phenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(4-methoxystyryl)-5-(4-methoxyphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(4-tert-butyl-styryl)-5-(4-tert-butyl-phenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(4-isopropyl-styryl)-5-(4-isopropyl 1-phenyl-3-(4-isopropylstyryl)-5-(4-isopropylphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(4-methoxystyryl)-5-(4-methoxyphenyl)-pyrazoline, 1-phenyl-3-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(3,4-dimethoxystyryl)-5-(3,4-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(2,6-dimethoxystyryl)-5 -(2,6-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(2,5-dimethoxystyryl)-5-(2,5-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(2,4-dimethoxystyryl)-5-(2,4-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(3,4-dimethoxystyryl)-5-(3,4-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(2,6-dimethoxystyryl)-5-(2,6-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(2,5-dimethoxystyryl)-5-(2,5-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(2,4-dimethoxystyryl)-5-(2 ,4-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(3,4-dimethoxystyryl)-5-(3,4-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(2,6-dimethoxystyryl)-5-(2,6-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(2,5-dimethoxystyryl)-5 -(2,5-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(2,4-dimethoxystyryl)-5-(2,4-dimethoxyphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(3,4-dimethoxystyryl)-5- (3,4-Dimethoxyphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(2,6-dimethoxystyryl)-5-(2,6-dimethoxyphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(2,5-dimethoxystyryl)-5-(2,5-dimethoxyphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)-pyrazoline, and 1-(4-isopropyl-phenyl)-3-(2,4-dimethoxystyryl)-5-(2,4-dimethoxyphenyl)-pyrazoline.

[0062] Examples of anthracene compounds include 9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, 9,10-dipropoxyanthracene, 9,10-dibutoxyanthracene, and 9,10-dipentoxyanthracene.

[0063] From the viewpoint of improving photosensitivity and resolution, the content of the component (D) may be 0.01 to 5 parts by mass, 0.01 to 1 part by mass, or 0.01 to 0.2 parts by mass relative to 100 parts by mass of the total amount of the components (A) and (B).

[0064] The photosensitive resin composition according to this embodiment may further contain, as necessary, additives such as dyes, photocoloring agents, thermal color-developing inhibitors, plasticizers, pigments, fillers, antifoaming agents, flame retardants, adhesion promoters, leveling agents, release promoters, antioxidants, fragrances, imaging agents, thermal crosslinking agents, polymerization inhibitors, etc. These additives may be used alone or in combination of two or more.

[0065] Examples of dyes include malachite green, Victoria Pure Blue, brilliant green, and methyl violet. Examples of photochromic agents include tribromophenyl sulfone, leucocrystal violet, diphenylamine, benzylamine, triphenylamine, diethylaniline, and o-chloroaniline. Examples of plasticizers include p-toluenesulfonamide.

[0066] The photosensitive resin composition can be dissolved, as needed, in a solvent such as methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N,N-dimethylformamide, propylene glycol monomethyl ether, or a mixed solvent thereof to prepare a solution with a solids content of about 30 to 60 mass %.

[0067] (middle class) The photosensitive element of this embodiment may include an intermediate layer (not shown) between the support film 10 and the photosensitive layer 20. The adhesive strength between the support film and the intermediate layer may be weaker than the adhesive strength between the intermediate layer and the photosensitive layer. The intermediate layer may be water-soluble or soluble in a developer. The intermediate layer is a layer formed using a resin composition for forming an intermediate layer, which will be described later.

[0068] The resin composition for forming an intermediate layer may contain a water-soluble resin. The inclusion of a water-soluble resin tends to improve the solubility of the intermediate layer to be formed. Furthermore, the layer separation between the intermediate layer to be formed and the photosensitive layer tends to be maintained for a long period of time, thereby improving stability. Examples of water-soluble resins include polyvinyl alcohol and polyvinylpyrrolidone. The resin composition for forming an intermediate layer may contain polyvinyl alcohol, which has a low oxygen permeability coefficient and can further suppress deactivation of radicals generated by actinic rays used for exposure. Polyvinyl alcohol can be obtained, for example, by saponifying polyvinyl acetate obtained by polymerizing vinyl acetate. The saponification degree of the polyvinyl alcohol used in this embodiment may be 50 mol% or more, 70 mol% or more, or 80 mol% or more. Using polyvinyl alcohol with a saponification degree of 50 mol% or more can further improve the gas barrier properties of the intermediate layer and tend to further improve the resolution of the formed resist pattern. The "saponification degree" in this specification refers to a value measured in accordance with JIS K 6726 (1994) (Testing method for polyvinyl alcohol) specified by the Japanese Industrial Standards. The upper limit of the saponification degree may be 100 mol%.

[0069] The average degree of polymerization of polyvinyl alcohol may be 300 to 3500, 300 to 2500, or 300 to 1000. The average degree of polymerization of polyvinylpyrrolidone may be 10000 to 100000, or 10000 to 50000. Two or more types of polyvinyl alcohol differing in saponification degree, viscosity, polymerization degree, modified species, etc. may be used in combination.

[0070] The resin composition for forming an intermediate layer may contain a resin soluble in a developer. The resin soluble in a developer may contain, for example, the component (A) or the component (B) used in a photosensitive resin composition. The inclusion of a resin soluble in a developer tends to improve the adhesion between the intermediate layer and the photosensitive layer to be formed, and also tends to make it easier to form a photosensitive layer on the intermediate layer to be formed.

[0071] The resin composition for forming an intermediate layer may contain at least one solvent, as necessary, to improve the handleability of the resin composition or to adjust the viscosity and storage stability. Examples of the solvent include water and organic solvents. Examples of the organic solvent include methanol, acetone, toluene, and mixed solvents thereof. Methanol may be contained to improve the efficiency of drying when forming the intermediate layer. Furthermore, when the resin composition for forming an intermediate layer contains a water-soluble resin, water, and methanol, the content of methanol may be 1 to 100 parts by mass, 10 to 80 parts by mass, or 20 to 60 parts by mass per 100 parts by mass of water, from the viewpoint of solubility in the water-soluble resin. The content of the water-soluble resin may be 1 to 50 parts by mass or 10 to 30 parts by mass per 100 parts by mass of water.

[0072] The resin composition for forming an intermediate layer may contain known additives such as surfactants, plasticizers, and leveling agents. Examples of leveling agents include silicone-based leveling agents. Examples of commercially available silicone-based leveling agents include Polyflow KL-401 (manufactured by Kyoeisha Chemical Co., Ltd.). When a leveling agent is contained, the content of the leveling agent may be 0.01 to 2.0 parts by mass or 0.05 to 1.0 parts by mass per 100 parts by mass of the resin composition for forming an intermediate layer, from the viewpoint of ease of forming the intermediate layer.

[0073] The surfactant may include a silicone surfactant or a fluorine surfactant from the viewpoint of improving peelability from the support film. These surfactants may be used alone or in combination of two or more. When a surfactant is contained, the content of the surfactant may be 0.01 to 1.0 parts by mass, 0.05 to 0.5 parts by mass, or 0.1 to 0.3 parts by mass per 100 parts by mass of the resin composition for forming an intermediate layer from the viewpoint of ease of forming the intermediate layer.

[0074] The plasticizer may contain, for example, a polyhydric alcohol compound in order to improve the ease of forming the intermediate layer. Examples of the plasticizer include glycerins such as glycerin, diglycerin, and triglycerin; (poly)alkylene glycols such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, and polypropylene glycol; and trimethylolpropane. These plasticizers may be used alone or in combination of two or more.

[0075] The thickness of the intermediate layer is not particularly limited, but may be 12 μm or less, 10 μm or less, or 8 μm or less from the viewpoint of developability, and may be 1.0 μm or more, 1.5 μm or more, or 2 μm or more from the viewpoint of ease of forming the intermediate layer and resolution.

[0076] [Method for manufacturing photosensitive element] The method for manufacturing a photosensitive element according to this embodiment includes the steps of forming a photosensitive layer on a support film using a photosensitive resin composition, and laminating the outer surface of a roll-shaped protective film onto the photosensitive layer.

[0077] The photosensitive layer 20 of the photosensitive element 1 can be formed by applying a photosensitive resin composition to one surface 10a of the support film and drying it. The application can be carried out using a known method such as roll coating, comma coating, gravure coating, air knife coating, die coating, or bar coating. Drying can be carried out at 70 to 150°C for about 5 to 30 minutes.

[0078] Since the protective film 30 has a weld line in the longitudinal direction of the inner surface of the roll, the other surface 30b, which is the outer surface of the rolled protective film, is bonded to one surface 20a of the photosensitive layer. When bonding the protective film 30 to the photosensitive layer 20, for example, a turret-type unwinding and winding device can be used. In this case, using a device that can reversibly rotate the turret can improve the productivity of photosensitive elements.

[0079] [Photosensitive element roll] Fig. 3 is a perspective view showing a photosensitive element roll according to one embodiment. The photosensitive element roll 300 shown in Fig. 3 includes a winding core 301 and a wound body of the photosensitive element 1 wound around the winding core 301. The photosensitive element 1 may be stored (preserved) in any form, but can be stored in the form of the photosensitive element roll 300 in which the photosensitive element 1 is wound into a roll.

[0080] The winding core 301 has, for example, a cylindrical shape. The material of the winding core 301 is not particularly limited as long as it is a conventionally used material, and examples thereof include plastics such as polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, and ABS resin (acrylonitrile-butadiene-styrene copolymer). The photosensitive element 1 is preferably wound up so that the support film 10 is on the outermost side.

[0081] [Method for forming resist pattern] The method for forming a resist pattern according to this embodiment includes a lamination step of laminating the photosensitive layer 20 of the photosensitive element 1 onto a substrate in the order of the photosensitive layer and the support film; an exposure step of irradiating a predetermined portion of the photosensitive layer 20 with active light through the support film 10 to form a photocured portion; and a development step of removing areas of the photosensitive layer 20 other than the photocured portion.

[0082] In the lamination step, for example, a protective film is removed from the photosensitive element, and the photosensitive layer and support film of the photosensitive element are laminated on the substrate in this order. In the lamination step, a method for laminating the photosensitive layer 20 on the substrate includes, for example, removing the protective film, and then heating the photosensitive layer 20 to about 70 to 130°C while pressing the layer onto the substrate at a pressure of about 0.1 to 1 MPa. In the lamination step, lamination can also be performed under reduced pressure. The surface of the substrate on which the photosensitive layer 20 is laminated is usually a metal surface, but is not particularly limited. To further improve lamination properties, the substrate may be preheated.

[0083] In the exposure step, the support film is removed or a predetermined portion of the photosensitive layer 20 is irradiated with actinic rays through the support film 10 to form a photocured portion in the photosensitive layer 20. Examples of exposure methods include a method of irradiating actinic rays in an imagewise manner through a negative or positive mask pattern called artwork (mask exposure method), a method of irradiating actinic rays in an imagewise manner by a projection exposure method, and a method of irradiating actinic rays in an imagewise manner by a direct writing exposure method such as an LDI (Laser Direct Imaging) exposure method or a DLP (Digital Light Processing) exposure method.

[0084] As the light source of the actinic rays, a known light source can be used, for example, a carbon arc lamp, a mercury vapor arc 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, or the like, which effectively emits ultraviolet light or visible light.

[0085] From the viewpoint of improving adhesion, post-exposure bake (PEB) may be performed after exposure and before development. The temperature when performing PEB may be 50 to 100° C. As a heater, a hot plate, a box-type dryer, a heating roll, or the like may be used.

[0086] In the development step, at least a portion of the photosensitive layer other than the photocured portion is removed from the substrate, thereby forming a resist pattern on the substrate.

[0087] In the development step, the support film 10 is peeled off and removed from the photosensitive layer 20, and then the areas of the photosensitive layer other than the photocured portions are removed. In the development step, the unexposed portions (unphotocured portions) of the photosensitive layer 20 are removed and developed by, for example, wet development using a developer such as an alkaline aqueous solution, a water-based developer, or an organic solvent, or dry development, to produce a resist pattern.

[0088] Examples of alkaline aqueous solutions include 0.1 to 5% by mass sodium carbonate solution, 0.1 to 5% by mass potassium carbonate solution, and 0.1 to 5% by mass sodium hydroxide solution. The pH of the alkaline aqueous solution is preferably in the range of 9 to 11. The temperature of the alkaline aqueous solution is adjusted according to the developability of the photosensitive layer 20. The alkaline aqueous solution may also contain a surfactant, an antifoaming agent, an organic solvent, etc. Examples of development methods include dipping, spraying, brushing, and slapping.

[0089] As a treatment after the development step, if necessary, heating at about 60 to 250°C or 0.2 to 10 J / cm 2 The resist pattern may be further hardened by exposing it to light.

[0090] [Printed wiring board manufacturing method] 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 by the above-described method for forming a resist pattern, where the substrate is etched or plated by a known method using the resist pattern as a mask.

[0091] Examples of the etching solution used for etching include a cupric chloride solution, a ferric chloride solution, and an alkaline etching solution. Examples of plating include copper plating, solder plating, nickel plating, and gold plating.

[0092] After etching or plating, the resist pattern can be stripped off, for example, with an aqueous solution that is more strongly alkaline than the aqueous solution used for development. Examples of such strongly alkaline solutions include a 1-10% by mass aqueous solution of sodium hydroxide and a 1-10% by mass aqueous solution of potassium hydroxide. Examples of stripping methods include immersion and spraying. The printed wiring board on which the resist pattern is formed may be a multilayer printed wiring board and may have small-diameter through-holes.

[0093] When plating is performed on a substrate having an insulating layer and a conductor layer formed on the insulating layer, it is necessary to remove the conductor layer other than the resist pattern. Examples of this removal method include a method of lightly etching after peeling off the resist pattern, and a method of masking the wiring area with solder by peeling off the resist pattern after solder plating or the like following the plating, and then treating the conductor layer with an etching solution that can etch only the areas not masked with solder.

[0094] Although the preferred embodiments of the present disclosure have been described above, the present invention is not limited to the above embodiments. [Example]

[0095] The present disclosure will be specifically described below based on examples, but the present invention is not limited thereto.

[0096] [Photosensitive resin composition] Photosensitive resin compositions were prepared by mixing the components in the amounts (parts by mass) shown in Table 1. Details of each component shown in Table 1 are as follows.

[0097] (binder polymer) A-1: Ethylene glycol monomethyl ether / toluene solution (solid content: 40% by mass) of a copolymer of methacrylic acid / methyl methacrylate / styrene / benzyl methacrylate (mass ratio: 27 / 5 / 45 / 23, Mw: 45,000, acid value: 107 mg KOH / g) (Photopolymerizable compound) FA-321M: EO-modified bisphenol A dimethacrylate (manufactured by Showa Denko Materials Co., Ltd., number of EO groups: 10 (average value)) FA-024M: Polyalkylene glycol dimethacrylate (manufactured by Showa Denko Materials Co., Ltd., number of EO groups: 12 (average value), number of PO groups: 4 (average value)) BPE-200: 2,2-bis(4-(methacryloxydiethoxy)phenyl)propane (Shin-Nakamura Chemical Co., Ltd.) (Photopolymerization initiator) B-CIM: 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole (Hodogaya Chemical Co., Ltd.) (sensitizer) EAB: 4,4'-bis(diethylamino)benzophenone (Hodogaya Chemical Co., Ltd.)

[0098] [Table 1]

[0099] A polyethylene terephthalate film (manufactured by Toray Industries, Inc., product name: FB-40, thickness: 16 μm) was prepared as the support film. A polyethylene film (manufactured by Tamapoly Corporation, product name: NF-15, thickness: 19 μm) with a weld line 66.5 μm wide and 1.6 μm high on the inner surface of the roll was prepared as the protective film.

[0100] [Photosensitive element] Example 1 The photosensitive resin composition solution was uniformly applied to a support film using a comma coater. The coating was then dried for 2 minutes in a hot air convection dryer at 100°C to form a 15 μm-thick photosensitive layer. The outer surface of the protective film was then attached to the photosensitive layer to produce a photosensitive element.

[0101] (Comparative Example 1) A photosensitive element was prepared in the same manner as in Example 1, except that the inner surface of the protective film was laminated onto the photosensitive layer.

[0102] (evaluation) The photosensitive element was wound around a cylindrical core (width 560 mm, outer diameter 84 mm, inner diameter 76 mm) under a tension of 90 N / m so that the protective film was on the inside and the support film was on the outside, to prepare a photosensitive element roll.

[0103] The photosensitive element of Example 1 was able to prevent air entrainment during winding, and was able to suppress the transfer of the weld line of the protective film to the photosensitive layer. [Explanation of symbols]

[0104] 1...photosensitive element, 10...support film, 10a...one side, 10b...other side, 20...photosensitive layer, 20a...one side, 20b...other side, 30...protective film, 30a...one side, 30b...other side, 32...weld line, 300...photosensitive element roll, 301...winding core.

Claims

1. A support film; a photosensitive layer provided on one surface of the support film; a protective film provided on the opposite surface of the photosensitive layer to the support film, The photosensitive element, wherein the protective film has a weld line on the surface opposite to the photosensitive layer.

2. The photosensitive element of claim 1 , wherein the protective film is a polyethylene film.

3. 3. The photosensitive element of claim 1, wherein the weld line has a width of 45 to 300 μm.

4. 4. The photosensitive element of claim 3, wherein the weld line has a height of 0.10 to 3.0 μm.

5. forming a photosensitive layer on a support film using a photosensitive resin composition; a step of laminating an outer surface of a roll-shaped protective film onto the photosensitive layer; Equipped with The method for producing a photosensitive element, wherein the protective film has a weld line on the inner surface of the roll in the longitudinal direction.

6. The method for producing a photosensitive element according to claim 5 , wherein the protective film is a polyethylene film.

7. The method for producing a photosensitive element according to claim 5 or 6, wherein the width of the weld line is 45 to 300 μm.

8. The method for producing a photosensitive element according to claim 7, wherein the height of the weld line is 0.10 to 3.0 μm.

Images