Photosensitive resin composition, photosensitive element, method for forming resist pattern, and method for manufacturing wiring substrate

Abstract

The photosensitive resin composition according to the present invention contains a binder polymer, a photopolymerizable compound, a photopolymerization initiator, and a sensitizer, and the photopolymerizable compound contains a monofunctional (meth) acrylate having a bicyclic skeleton, and the photopolymerization initiator and the sensitizer are contained in an amount of 100 parts by mass relative to the total of 100 parts by mass of the binder polymer and the photopolymerizable compound. The content of a monofunctional (meth) acrylate having a bicyclic skeleton is less than 5.0 parts by mass.

Description

TECHNICAL FIELD

[0001] The present application relates to a photosensitive resin composition, a photosensitive element, a method for forming a resist pattern, and a method for manufacturing a wiring substrate. BACKGROUND

[0002] In the field of manufacturing a wiring substrate, as a resist material used in etching treatment or plating treatment, a photosensitive resin composition and a photosensitive element provided with a layer (hereinafter, also referred to as "photosensitive layer") formed on a support using the photosensitive resin composition can be widely used.

[0003] A wiring substrate is manufactured, for example, by the following sequence. First, a photosensitive layer of a photosensitive element is laminated on a substrate for circuit formation (photosensitive layer formation step). Next, a prescribed portion of the photosensitive layer is exposed to light, and a photocured portion is formed (exposure step). At this time, the support is peeled off before or after exposure. Then, the region of the photosensitive layer other than the photocured portion is removed from the substrate, and a resist pattern as a cured product of the photosensitive resin composition is formed on the substrate (development step). Next, the obtained resist pattern is used as a resist, and etching treatment or plating treatment is performed to form a conductor pattern on the substrate (circuit formation step), and finally, the resist is peeled off and removed (peeling step).

[0004] As a method for exposure, a method in which a mercury lamp is used as a light source and exposure is performed via a photomask has been known in the past. Also, in recent years, as an exposure method which does not require a photomask, a direct drawing exposure method called LDI (Laser Direct Imaging) in which digital data of a pattern is directly drawn on a photosensitive layer has been used. With this direct drawing exposure method, the positional alignment accuracy is better than that of the exposure method via a photomask, and a high-precision pattern can be obtained, and thus it has been introduced for the manufacture of high-density package substrate.

[0005] Generally, in the exposure step, in order to improve the production efficiency, it is desirable to shorten the exposure time. However, in the above-described direct drawing exposure method, in addition to the use of monochromatic light such as laser light as a light source, the substrate is scanned and active light is irradiated, and thus there is a tendency to require more exposure time compared to the conventional exposure method via a photomask. Therefore, in order to shorten the exposure time and improve the production efficiency, it is necessary to further improve the sensitivity of the photosensitive resin composition.

[0006] In the peeling step, in order to improve the production efficiency, it is desirable to shorten the peeling time of the resist. Therefore, a photosensitive resin composition which is excellent in the peeling property after curing is required. Also, with the high densification of the wiring substrate in recent years, a photosensitive resin composition which can form a resist pattern excellent in resolution and adhesion is also required.

[0007] For these requirements, in the past, various photosensitive resin compositions have been studied. For example, in Patent Literature 1, a photosensitive resin composition excellent in sensitivity and resolution by using a specific photosensitizer is disclosed. In Patent Literature 2, a photosensitive resin composition excellent in sensitivity and resolution by using a specific alkali-soluble polymer and a compound having an ethylenic unsaturated double bond is disclosed.

[0008] Prior Art Documents Patent Literature Patent Literature 1: Japanese Patent Application Laid-Open No. 2009-003177 Patent Literature 2: Japanese Patent Application Laid-Open No. 2013-061556 SUMMARY

[0009] Technical Problem to be Solved by the Invention In recent years, for example, in order to form a copper pillar for connecting an IC chip and a wiring board for a semiconductor package, a photosensitive resin composition is required to form a resist pattern such as a via pattern with high resolution. However, the thicker the thickness of a photosensitive layer formed using a photosensitive resin composition, the more difficult it is to uniformly cure to the bottom, and thus it is difficult to form a resist pattern having sufficient resolution and adhesion. In addition, a resist pattern excellent in adhesion has a tendency that the peeling time becomes long. Therefore, a photosensitive resin composition is required to form a resist pattern excellent in adhesion and resolution, and excellent in peeling property after curing.

[0010] An object of the present application is to provide a photosensitive resin composition excellent in resolution, adhesion, and peeling property, a photosensitive element using the photosensitive resin composition, a method for forming a resist pattern, and a method for manufacturing a wiring board.

[0011] Means for Solving the Technical Problem The present application provides the following: a photosensitive resin composition, a photosensitive element, a method for forming a resist pattern, and a method for manufacturing a wiring board.

[0012] [1] A photosensitive resin composition containing a binder polymer, a photopolymerizable compound, a photopolymerization initiator, and a sensitizer, wherein the photopolymerizable compound contains a monofunctional (meth)acrylate having a bicyclic skeleton, the content of the monofunctional (meth)acrylate having a bicyclic skeleton is less than 5.0 parts by mass with respect to 100 parts by mass of the total amount of the binder polymer and the photopolymerizable compound.

[0013] [2] The photosensitive resin composition according to the above [1], wherein the content of the monofunctional (meth)acrylate having a bicyclic skeleton is 1.0 to 4.5 parts by mass, relative to 100 parts by mass of the total amount of the binder polymer and the photopolymerizable compound.

[0014] [3] The photosensitive resin composition according to the above [1] or [2], wherein the photopolymerizable compound further comprises a bisphenol A type (meth)acrylate.

[0015] [4] The photosensitive resin composition according to any one of the above [1] to [3], wherein the sensitizer comprises an anthracene compound.

[0016] [5] A photosensitive element comprising a support and a photosensitive layer formed on the support using the photosensitive resin composition according to any one of the above [1] to [4].

[0017] [6] The photosensitive element according to the above [5], wherein the thickness of the photosensitive layer is 30 μm or more.

[0018] [7] A method for forming a resist pattern, comprising the steps of: forming a photosensitive layer on a substrate using the photosensitive element according to the above [6]; forming a photocured portion by irradiating active light to at least a part of the photosensitive layer; and forming a resist pattern by removing a non-photocured portion of the photosensitive layer from the substrate.

[0019] [8] A method for manufacturing a wiring substrate, comprising the step of forming a conductor pattern by performing etching treatment or plating treatment on a substrate on which a resist pattern is formed by the method for forming a resist pattern according to the above [7].

[0020] [9] The method for manufacturing a wiring substrate according to the above [8], further comprising the step of removing the resist pattern using an organic alkali stripping solution after the etching treatment or the plating treatment.

[0021] Effects of the Invention According to the present invention, it is possible to provide a photosensitive resin composition, a photosensitive element using the same, a method for forming a resist pattern, and a method for manufacturing a wiring substrate, which are excellent in resolution, adhesion, and peeling properties. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a schematic cross-sectional view showing one embodiment of a photosensitive element. DETAILED DESCRIPTION

[0023] The embodiments of the present invention will now be described in detail. In this specification, the term "process" is included not only as an independent process, but also as long as the desired function of the process can be achieved, even if it cannot be clearly distinguished from other processes. When viewed in a top view, the term "layer" includes not only structures formed on the entire surface, but also structures formed on a portion of the surface. The numerical range indicated by "~" represents the range in which the values ​​described before and after "~" are the minimum and maximum values, respectively. Within the numerical ranges described in stages in this specification, the upper or lower limit of the numerical range for a certain stage can be replaced by the upper or lower limit of the numerical range for other stages. Within the numerical ranges described in this specification, the upper or lower limit of the numerical range can be replaced by the values ​​shown in the embodiments.

[0024] In this specification, "(meth)acrylate" means at least one of "acrylate" and its corresponding "methacrylate". The same applies to other similar expressions such as "(meth)acryloyl". "EO" represents ethylene oxide, and "EO-modified" compounds refer to compounds containing an oxyethylidene group. "PO" represents propylene oxide, and "PO-modified" compounds refer to compounds containing an oxypropylene group.

[0025] In this specification, the amounts of each component in the photosensitive resin composition refer to the total amount of each component unless otherwise specified. In this specification, "solid component" refers to the non-volatile component in the photosensitive resin composition after volatile substances (water, solvents, etc.) have been removed. That is, "solid component" refers to components other than solvents that do not volatilize during the drying process of the photosensitive resin composition (described later), including components that are liquid, syrupy, or waxy at room temperature (25°C).

[0026] [Photosensitive Resin Composition] The photosensitive resin composition according to this embodiment contains (A) an adhesive polymer (hereinafter, sometimes referred to as "component (A)"), (B) a photopolymerizable compound (hereinafter, sometimes referred to as "component (B)"), (C) a photopolymerization initiator (hereinafter, sometimes referred to as "component (C)"), and (D) a sensitizer (hereinafter, sometimes referred to as "component (D)"). The photopolymerizable compound comprises a monofunctional (meth)acrylate having a bicyclic backbone, and the content of the monofunctional (meth)acrylate having a bicyclic backbone in the photosensitive resin composition is less than 5.0 parts by weight relative to 100 parts by weight of the total amount of the adhesive polymer and the photopolymerizable compound. The photosensitive resin composition according to this embodiment, by containing this specific photopolymerizable compound within a specific range, exhibits excellent resolution, adhesion, and peelability, and can be suitable for thick film applications. The components will be described below.

[0027] (A) Component: Adhesive polymer) The photosensitive resin composition comprises one or more of component (A). Examples of component (A) include acrylic resins, styrene resins, epoxy resins, amide resins, amide-epoxy resins, alkyd resins, and phenolic resins.

[0028] From the viewpoint of alkaline developability, component (A) may contain acrylic resins. Acrylic resins are resins having structural units (monomer units) derived from compounds containing (meth)acryloyl groups.

[0029] Compounds containing a (meth)acrylyl group are compounds containing a (meth)acrylyl group. Examples of compounds containing a (meth)acrylyl group include hydroxyalkyl (meth)acrylates, (meth)acrylic acid, alkyl (meth)acrylates, aryl (meth)acrylates, cycloalkyl (meth)acrylates, acrylamides such as diacetone acrylamide, tetrahydrofurfuryl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, glycidyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, α-bromoacrylic acid, α-chloroacrylic acid, β-furfuryl (meth)acrylate, and β-styryl (meth)acrylate.

[0030] Acrylic resins can be, for example, polymers having at least one selected from the group consisting of (meth)acrylic units, (meth)acrylic alkyl ester units, (meth)acrylic aryl ester units, and hydroxyalkyl (meth)acrylic ester units (a).

[0031] The (meth)acrylic acid unit is a structural unit derived from (meth)acrylic acid. When polymer (a) has (meth)acrylic acid units, based on the total amount of monomer units constituting polymer (a) (100% by mass), from the viewpoint of resolution and adhesion, the content of (meth)acrylic acid units can be 5% or more by mass, 10% or more by mass, 15% or more by mass, 20% or more by mass, or 25% or more by mass, or it can be less than 50% by mass, less than 45% by mass, less than 40% by mass, less than 35% by mass, or less than 30% by mass.

[0032] The (meth)acrylate alkyl ester unit is a structural unit derived from (meth)acrylate alkyl esters. The alkyl group of (meth)acrylate alkyl esters can be, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, or structural isomers thereof, and from the viewpoint of exfoliation, can be an alkyl group having 1 to 4 carbon atoms.

[0033] When polymer (a) has alkyl (meth)acrylate units, based on the total amount of monomer units constituting polymer (a), from the viewpoint of peelability, the content of alkyl (meth)acrylate units can be 1% or more by mass, 2% or more by mass, or 3% or more by mass, and from the viewpoint of resolution and adhesion, it can be 30% or less by mass, 20% or less by mass, 10% or less by mass, or 8% or less by mass.

[0034] The aryl methacrylate unit is a structural unit derived from aryl methacrylate. Examples of aryl methacrylates include benzyl methacrylate, phenyl methacrylate, and naphthyl methacrylate. When polymer (a) has aryl methacrylate units, based on the total amount of monomer units constituting polymer (a), from the viewpoint of resolution and tightness, the content of aryl methacrylate units can be 5% by mass or more, 10% by mass or more, 15% by mass or more, or 20% by mass or more, or it can be 40% by mass or less, 35% by mass or less, 30% by mass or less, or 25% by mass or less.

[0035] The hydroxyalkyl (meth)acrylate unit is a structural unit derived from hydroxyalkyl (meth)acrylates. Examples of hydroxyalkyl (meth)acrylates include hydroxy(meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxypentyl (meth)acrylate, and hydroxyhexyl (meth)acrylate. When the alkyl portion of the hydroxyalkyl (meth)acrylate unit has 3 or more carbon atoms, it may also have a branched structure.

[0036] When polymer (a) has hydroxyalkyl (meth)acrylate units, based on the total amount of monomer units constituting polymer (a), from the viewpoint of dispersibility, the content of hydroxyalkyl (meth)acrylate units may be 0.5% by mass or more, 0.75% by mass or more, or 1.0% by mass or more, and from the viewpoint of water absorption, it may be 20% by mass or less, 15% by mass or less, or 8% by mass or less.

[0037] To further improve the resolution and adhesion of the photosensitive resin composition, the polymer (a) may have structural units derived from styrene or styrene derivatives (hereinafter also referred to as "styrene-based units"). Examples of styrene derivatives include vinyltoluene, p-methylstyrene, p-methylstyrene, and p-ethylstyrene.

[0038] When polymer (a) contains styrene units, based on the total amount of monomer units constituting polymer (a), from the viewpoint of resolution, the content of styrene units can be 35% by mass or more, 40% by mass or more, 43% by mass or more, or 45% by mass or more, and from the viewpoint of reproducibility, the content of styrene units can be 70% by mass or less, 60% by mass or less, 50% by mass or less, or 48% by mass or less.

[0039] Polymer (a) may further have structural units derived from other monomers besides those described above. Examples of other monomers include, for instance, ethers of vinyl alcohol such as acrylonitrile and vinyl-n-butyl ether, maleic acid, maleic anhydride, monomethyl maleate, monoethyl maleate, monoisopropyl maleate, fumaric acid, cinnamic acid, α-cyanocinonic acid, itconic acid, crotonic acid, and propynic acid.

[0040] Component (A) may contain adhesive polymers other than polymer (a), or may consist only of polymer (a). From the viewpoint of adhesion and resolution, based on the total amount of component (A), the content of polymer (a) in component (A) may be 50% to 100% by mass, or 80% to 100% by mass.

[0041] From the viewpoint of developability, the acid value of polymer (a) can be 100 mg KOH / g or more, 120 mg KOH / g or more, 140 mg KOH / g or more, 150 mg KOH / g or more, 160 mg KOH / g or more, or 170 mg KOH / g or more. From the viewpoint of the adhesion (developer resistance) of the cured photosensitive resin composition, the acid value of polymer (a) can be 250 mg KOH / g or less, 240 mg KOH / g or less, 230 mg KOH / g or less, 200 mg KOH / g or less, or 190 mg KOH / g or less. The acid value of polymer (a) can be adjusted by the content of the structural units constituting polymer (a) (e.g., (meth)acrylic acid units). When component (A) contains other adhesive polymers besides polymer (a), the acid values ​​of the other adhesive polymers can also be within the above ranges.

[0042] From the viewpoint of the adhesion (developer resistance) of the cured photosensitive resin composition and the ease with which a thick-film resist pattern can be formed, the weight-average molecular weight (Mw) of polymer (a) can be 10,000 or more, 20,000 or more, 25,000 or more, 30,000 or more, 35,000 or more, 40,000 or more, or 45,000 or more. From the viewpoint of developability, it can be 100,000 or less, 80,000 or less, 60,000 or less, or 50,000 or less. The dispersion (Mw / Mn) of polymer (a) can, for example, be 1.0 or more or 1.5 or more. From the viewpoint of adhesion and resolution, the dispersion (Mw / Mn) of polymer (a) can be 3.0 or less or 2.5 or less. When component (A) includes other adhesive polymers besides polymer (a), the Mw of the other adhesive polymers can also be within the above ranges.

[0043] Weight-average molecular weight and dispersity can be determined, for example, by gel permeation chromatography (GPC) using a calibration curve of standard polystyrene. More specifically, they can be determined under the conditions described in the examples. Furthermore, for compounds with low molecular weights, where it is difficult to determine the weight-average molecular weight using the methods described above, the molecular weight can be determined by other methods, and its average calculated.

[0044] Based on the total amount of solid components in the photosensitive resin composition, from the viewpoint of film formability, the content of component (A) can be 20% or more by mass, 30% or more by mass, or 40% or more by mass, and from the viewpoint of sensitivity and resolution, it can be 90% or less by mass, 80% or less by mass, 70% or less by mass, or 65% or less by mass.

[0045] From the perspective of membrane formability, the content of component (A) relative to the total amount of components (A) and (B) 100 parts by mass can be 30 or more, 40 or more, or 50 or more parts by mass. From the perspective of sensitivity and resolution, it can be 70 or less, 65 or less, or 60 or less parts by mass.

[0046] (B) Component: Photopolymerizable compound) In the photosensitive resin composition, from the viewpoint of peelability, component (B) contains a monofunctional (meth)acrylate having a bicyclic skeleton (hereinafter also referred to as "component (b1)"). From the viewpoint of adhesion and resolution, the content of component (b1) is less than 5.0 parts by mass relative to the total amount of component (A) and component (B) of 100 parts by mass.

[0047] Examples of components (b1) include dicyclopentyl methacrylate, isobornyl methacrylate, and adamantyl methacrylate.

[0048] From the perspective of balancing adhesion, resolution, and peelability, the content of component (b1) can be 1.0 to 4.5 parts by mass, 1.5 to 4.0 parts by mass, 2.0 to 3.5 parts by mass, or 2.5 to 3.3 parts by mass relative to the total amount of component (A) and component (B) of 100 parts by mass.

[0049] From the viewpoints of developability, resolution and peelability, component (B) may contain a difunctional (meth)acrylate as a compound having two (meth)acryloyl groups (hereinafter also referred to as "component (b2)"). Examples of components (b2) include bisphenol A type (meth)acrylates such as 2,2-bis(4-((meth)acryloyloxypolyethoxy)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; polyalkylene glycol di(meth)acrylates such as polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, and EO-modified polypropylene glycol di(meth)acrylate; and di(meth)acrylates with an alicyclic skeleton such as cyclohexyl di(meth)acrylate and tricyclodecanediethanol di(meth)acrylate.

[0050] As component (b2), from the viewpoint of further improving resolution and peelability, bisphenol A type (meth)acrylate is preferred, and 2,2-bis(4-((meth)acryloyloxypolyethoxy)phenyl)propane is more preferred.

[0051] From the perspective of further improving resolution and adhesion, relative to the total amount of 100 parts by mass of components (A) and (B), the content of component (b2) can be 20 or more parts by mass, 25 or more parts by mass, 30 or more parts by mass, or 35 or more parts by mass, or it can be less than 65 parts by mass, less than 60 parts by mass, less than 50 parts by mass, or less than 45 parts by mass. That is, relative to the total amount of 100 parts by mass of components (A) and (B), the content of component (b2) can be 20 to 65 parts by mass, 25 to 60 parts by mass, 30 to 50 parts by mass, or 35 to 45 parts by mass.

[0052] From the viewpoints of sensitivity, developability, and adhesion, component (B) may further include compounds having three or more (meth)acryloyl groups (hereinafter also referred to as component "(b3)"). Examples of components (b3) 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, EO-modified dipentaerythritol hexa(meth)acrylate, tetramethylolmethane tri(meth)acrylate, and tetramethylolmethane tetra(meth)acrylate.

[0053] Based on the total amount of component (B), the content of component (b3) can be more than 1% by mass, more than 5% by mass, or more than 10% by mass, or less than 25% by mass, less than 20% by mass, or less than 15% by mass.

[0054] The photosensitive resin composition may further include other photopolymerizable compounds other than components (b1), (b2) and (b3) as component (B).

[0055] Other photopolymerizable compounds include, for example, urethane monomers, nonylphenoxy polyethyleneoxy (meth)acrylates, phthalic acid compounds, alkyl (meth)acrylates, and photopolymerizable compounds having at least one cationicly polymerizable cyclic ether group within the molecule (oxobutane compounds, etc.). From the viewpoints of resolution, adhesion, resist shape, and peelability, other photopolymerizable compounds may be at least one selected from the group consisting of urethane monomers, nonylphenoxy polyethyleneoxy (meth)acrylates, and phthalic acid compounds.

[0056] Examples of nonylphenoxy polyoxyethylene (meth) acrylates include nonylphenoxy triethyleneoxy (meth) acrylate, nonylphenoxy tetraethyleneoxy (meth) acrylate, nonylphenoxy pentaethyleneoxy (meth) acrylate, nonylphenoxy hexaethyleneoxy (meth) acrylate, nonylphenoxy heptaethyleneoxy (meth) acrylate, nonylphenoxy octaethyleneoxy (meth) acrylate, nonylphenoxy nonaethyleneoxy (meth) acrylate, nonylphenoxy decaethyleneoxy (meth) acrylate, and nonylphenoxy undecaethyleneoxy (meth) acrylate.

[0057] Examples of phthalic acid compounds include γ-chloro-β-hydroxypropyl-β'-(meth)acryloyloxyethyl-phthalic acid (also known as 3-chloro-2-hydroxypropyl-2-(meth)acryloyloxyethyl-phthalic acid), β-hydroxyethyl-β'-(meth)acryloyloxyethyl-phthalic acid, and β-hydroxypropyl-β'-(meth)acryloyloxyethyl-phthalic acid.

[0058] Based on the total amount of solid components in the photosensitive resin composition, from the viewpoint of sensitivity and resolution, the content of component (B) can be 3% or more by mass, 10% or more by mass, or 25% or more by mass, and from the viewpoint of film formability, it can be 70% or less by mass, 60% or less by mass, or 50% or less by mass.

[0059] (C) Component: Photopolymerization initiator) The photosensitive resin composition may contain one or more of the components (C). As for component (C), there are no particular limitations as long as it is a component capable of polymerizing component (B), and it can be appropriately selected from commonly used photopolymerization initiators.

[0060] Examples of components (C) include hexaaryl biimidazole compounds; benzophenone, 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)-1-butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinyl- Aromatic ketone compounds such as acetone-1; quinone compounds such as alkyl anthraquinones; benzoin ether compounds such as benzoin alkyl ethers; 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.

[0061] From the viewpoint of improving the adhesion between the photosensitive layer and the smooth substrate, component (C) may contain a hexaarylbiimidazole compound. The aryl group in the hexaarylbiimidazole compound may be phenyl or the like. The hydrogen atom bonded to the aryl group in the hexaarylbiimidazole compound may be replaced by a halogen atom (chlorine atom, etc.).

[0062] Hexaarylbiimidazole compounds can be 2,4,5-triarylimidazolium dimers. Examples of 2,4,5-triarylimidazolium dimers include 2-(o-chlorophenyl)-4,5-diphenylimidazolium dimer, 2-(o-chlorophenyl)-4,5-bis-(m-methoxyphenyl)imidazolium dimer, and 2-(p-methoxyphenyl)-4,5-diphenylimidazolium dimer.

[0063] Compared to the total amount of 100 parts by mass of components (A) and (B), the content of component (C) can be 1.0–10 parts by mass, 2.0–8 parts by mass, 3.0–7.0 parts by mass, or 4.0–6.0 parts by mass. When the content of component (C) is within this range, it is easy to improve both photosensitivity and resolution in a balanced way.

[0064] (D) Component: sensitizer) The photosensitive resin composition described in this embodiment, by containing component (D), can effectively utilize the absorption wavelength of the active light used in exposure.

[0065] Examples of components (D) include dialkylaminobenzophenone compounds, pyrazoline compounds, anthracene compounds, coumarin compounds, xanthonesone compounds, thioxanthonesone compounds, oxazole compounds, benzoxazole compounds, thiazole compounds, benzothiazole compounds, triazole compounds, stilbene compounds, triazine compounds, thiophene compounds, naphthalenedicarboximide compounds, triarylamine compounds, and aminoacridine compounds. From the viewpoint of further improving resolution and adhesion, component (D) may include anthracene compounds.

[0066] Examples of anthracene compounds include 9,10-dibutoxyanthracene, 9,10-diphenylanthracene, and 9,10-diethoxyanthracene. From the viewpoints of sensitivity, tightness, resolution, and exfoliation, anthracene compounds may include 9,10-dibutoxyanthracene.

[0067] From the perspective of improving sensitivity and resolution, relative to the total amount of components (A) and (B) 100 parts by mass, the content of component (D) can be more than 0.2 parts by mass, more than 0.3 parts by mass, more than 0.4 parts by mass, or more than 0.5 parts by mass, or less than 1.5 parts by mass, less than 1.0 parts by mass, less than 0.8 parts by mass, less than 0.75 parts by mass, or less than 0.7 parts by mass.

[0068] (Other ingredients) The photosensitive resin composition may further contain one or more other components besides those mentioned above. Examples of other components include polymerization inhibitors, hydrogen donors (bis[4-(dimethylamino)phenyl]methane, bis[4-(diethylamino)phenyl]methane, leuco crystal violet, N-phenylglycine, etc.), dyes (malachite green, etc.), tribromophenyl sulfone, photochromic agents, thermochromic inhibitors, plasticizers (p-toluenesulfonamide, etc.), pigments, fillers, defoamers, flame retardants, stabilizers, adhesion promoters, leveling agents, peel accelerators, antioxidants, fragrances, imaging agents, and thermal crosslinking agents. The content of other components may be 0.005 parts by mass or more, or 0.01 parts by mass or more, and may be 20 parts by mass or less, relative to the total amount of components (A) and (B) 100 parts by mass.

[0069] To improve the processability of the photosensitive resin composition or to adjust its viscosity and storage stability, an organic solvent may be included. Commonly used organic solvents can be used without particular restriction. Examples of organic solvents include methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N,N-dimethylformamide, and propylene glycol monomethyl ether. For example, components (A) to (D) can be dissolved in an organic solvent to create a solution with a solid content of approximately 30 to 60% by mass.

[0070] The photosensitive resin composition involved in this embodiment can be in liquid or film form (photosensitive film). For example, the photosensitive resin composition can be used as a negative photosensitive resin composition. The photosensitive resin composition can be suitably used in the methods for forming resist patterns and manufacturing wiring substrates described later.

[0071] [Photosensitive element] The photosensitive element of this embodiment includes a support and a photosensitive layer formed on the support, the photosensitive layer comprising the aforementioned photosensitive resin composition. The content of each component ((A) to (D) and other components) in the photosensitive layer, excluding volatile substances, can be within the numerical range of the content of each component in the aforementioned photosensitive resin composition. When using the photosensitive element according to this embodiment, after laminating the photosensitive layer onto a substrate, exposure can be performed without peeling off the support (support film).

[0072] Figure 1 This is a schematic cross-sectional view of a photosensitive element according to one embodiment. For example... Figure 1 As shown, the photosensitive element 1 comprises a support 2, a photosensitive layer 3 formed on the support 2 from the above-mentioned photosensitive resin composition, and other layers such as a protective layer 4 provided as needed.

[0073] The support 2 and the protective layer 4 can each be a polymer film with heat resistance and solvent resistance, such as a polyester film (e.g., polyethylene terephthalate film), a polyolefin film (e.g., polypropylene film), or a polyolefin film. The support 2 and the protective layer 4 can also be films made of hydrocarbon polymers other than polyolefins. Films containing polyolefin hydrocarbon polymers can have low density, for example, a density of 1.014 g / cm³. 3 The following density. Support 2 and protective layer 4 can each be a stretched film formed by stretching this low-density hydrocarbon polymer film. The type of polymer film constituting protective layer 4 can be the same as or different from the type of polymer film constituting support 2.

[0074] These polymer films can be purchased as, for example, polyethylene terephthalate films such as the PS series (e.g., PS-25) manufactured by Teijin Limited, polyethylene films such as NF-15 manufactured by TAMAPOLY CO., LTD., or polypropylene films such as ALPHAN MA-410 and E-200C manufactured by OJI PAPER CO., LTD., and SHIN-ETSU FILM CO., LTD.

[0075] Regarding the thickness of the support 2, from the viewpoint of being able to suppress the damage of the support 2 when it is peeled off from the photosensitive layer 3, it can be 1 μm or more or 5 μm or more. From the viewpoint of being able to be properly exposed when exposed through the support 2, it can be 100 μm or less, 50 μm or less or 30 μm or less.

[0076] From the viewpoint that the protective layer 4 can be protected from damage when the photosensitive layer 3 and the support 2 are laminated onto the substrate, the thickness of the protective layer 4 can be 1 μm or more, 5 μm or more, or 15 μm or more. From the viewpoint of improving productivity, it can be 100 μm or less, 50 μm or less, or 30 μm or less.

[0077] The photosensitive layer 3 is composed of the above-described photosensitive resin composition. The thickness of the photosensitive layer 3 after drying (after the organic solvent evaporates if the photosensitive resin composition contains organic solvent) can be 30 to 100 μm. From the viewpoint of forming a resist pattern with a high aspect ratio, the thickness of the photosensitive layer can be 30 μm or more, 35 μm or more, 38 μm or more, 40 μm or more, or 50 μm or more. From the viewpoint of peelability, the thickness of the photosensitive layer can be 100 μm or less, 90 μm or less, 80 μm or less, 70 μm or less, or 60 μm or less.

[0078] The photosensitive element 1 can be obtained, for example, by the following method. First, a photosensitive layer 3 is formed on the support 2. The photosensitive layer 3 can be formed, for example, by coating a photosensitive resin composition containing an organic solvent to form a coating layer and drying the coating layer. Next, a protective layer 4 is formed on the surface of the photosensitive layer 3 opposite to the support 2.

[0079] The coating layer is formed by known methods such as roller coating, comma coating, gravure coating, air knife coating, mold coating, and bar coating. The coating layer is dried so that the amount of organic solvent remaining in the photosensitive layer 3 is, for example, less than 2% by mass, specifically, for example, at 70 to 150°C for about 5 to 30 minutes.

[0080] The photosensitive element may further include an intermediate layer between the support 2 and the photosensitive layer 3. This intermediate layer may be a layer containing a water-soluble resin. Examples of water-soluble resins include those containing polyvinyl alcohol as a main component.

[0081] In another embodiment, the photosensitive element may not have a protective layer, or it may further have other layers such as a buffer layer, an adhesive layer, a light-absorbing layer, and a gas barrier layer.

[0082] The photosensitive element 1 can be in the form of a sheet or a roll of photosensitive elements wound around a core. In the photosensitive element roll, the photosensitive element 1 is preferably wound into the support 2 as the outer side. The core is formed, for example, of polyethylene, polypropylene, polystyrene, polyvinyl chloride, acrylonitrile-butadiene-styrene copolymer, etc. From the viewpoint of end-face protection, end-face partitions can be provided on the end faces of the photosensitive element roll; from the viewpoint of resistance to edge fusion, moisture-proof end-face partitions can be provided. The photosensitive element 1 can be packaged, for example, in a black sheet with low moisture permeability.

[0083] The photosensitive element 1 can be suitably used for forming resist patterns, and is particularly suitable for the manufacturing method of the printed wiring substrate described later.

[0084] [Methods for forming resist patterns] The method for forming a resist pattern according to this embodiment includes a step of forming a photosensitive layer on a substrate using the above-described photosensitive resin composition or the above-described photosensitive element (photosensitive layer formation step), a step of irradiating at least a portion (a predetermined portion) of the photosensitive layer with active light to form a photocurable portion (exposure step), and a step of removing at least a portion of the uncured portion from the substrate to form a resist pattern (development step). Other steps may be included as needed. The resist pattern is also called a photocurable pattern of the photosensitive resin composition, or an embossed pattern. The method for forming a resist pattern is also called a method for manufacturing a substrate with a resist pattern.

[0085] (Photosensitive layer formation process) As a method for forming a photosensitive layer on a substrate, one can, for example, coat and dry the aforementioned photosensitive resin composition, or remove the protective layer from the photosensitive element, heat the photosensitive layer of the photosensitive element, and then press it onto the substrate. When using a photosensitive element, a laminate consisting of a substrate, a photosensitive layer, and a support, which are sequentially stacked, can be obtained. There are no particular limitations on the substrate, but generally, a circuit forming substrate or an alloy substrate, such as a die pad (lead frame substrate), can be used.

[0086] Regarding the surface roughness (Ra) of the substrate, from the viewpoint of improving resolution by suppressing halos caused by substrate unevenness, it can be below 200 nm, below 180 nm, or below 160 nm. From the viewpoint of improving the adhesion of the resist pattern, it can be above 10 nm, above 30 nm, or above 40 nm. From the viewpoint of maintaining a balance between resolution and adhesion, Ra can be 10–200 nm, 30–180 nm, or 40–160 nm.

[0087] When using photosensitive elements, from the viewpoint of adhesion and tracking, the photosensitive layer formation process is preferably performed under reduced pressure. Heating of the photosensitive layer and / or substrate during lamination can be performed at a temperature of 70–130°C. Lamination can be performed at approximately 0.1–1.0 MPa (1–10 kgf / cm²). 2 The process is carried out under pressure of approximately 70-130°C, but these conditions can be selected as needed. Alternatively, if the photosensitive layer is heated to 70-130°C, preheating of the substrate is not required, but preheating of the substrate can be performed to further improve adhesion and tracking.

[0088] (Exposure process) In the exposure process, at least a portion of the photosensitive layer formed on the substrate is irradiated with active light, and the irradiated portion is photocured to form a latent image. At this time, if a support is present on the photosensitive layer, and the support is transmissive to the active light, the active light can be irradiated through the support. However, if the support is light-blocking, the active light is irradiated on the photosensitive layer after the support is removed.

[0089] As an exposure method, one example is the method of illuminating active light in an image-like manner through a negative or positive mask pattern called an inset (mask exposure method). Another method is the method of illuminating active light in an image-like manner using projection exposure. Furthermore, methods of illuminating active light in an image-like manner using direct drawing exposure methods such as LDI (Laser Direct Imaging) exposure and DLP (Digital Light Processing) exposure can also be employed.

[0090] As a source of active light, known light sources can be used, such as gas lasers like carbon arc lamps, mercury vapor arc lamps, high-pressure mercury lamps, xenon lamps, argon lasers, solid-state lasers like YAG lasers, semiconductor lasers, and other sources that emit ultraviolet or visible light.

[0091] (Developing process) In the development process, a resist pattern is formed on the substrate by removing at least a portion of the uncured portion (other than the photocurable portion) of the photosensitive layer. If a support is present on the photosensitive layer, the area other than the photocurable portion (also called the unexposed portion) is removed (developed) after the support is removed. There are wet development and dry development methods, but wet development is widely used.

[0092] In wet development, a developer solution corresponding to the photosensitive resin composition is used, and development is performed using a known development method. Examples of development methods include immersion, spin-dip, spray, brushing, washing, and agitation immersion. From the viewpoint of improving resolution, high-pressure spraying can also be used as a development method. Two or more of these methods can also be combined for development.

[0093] The composition of the developer can be appropriately selected based on the composition of the above-described photosensitive resin composition. Examples of developers include alkaline aqueous solutions and organic solvent developers.

[0094] From a safety, stability, and ease of operation standpoint, an alkaline aqueous solution can be used as the developer. Alkalis used in alkaline aqueous solutions include hydroxides such as lithium, sodium, or potassium hydroxides; 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; borax, sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1,3-propanediol, 1,3-diaminopropanol-2, morpholine, etc.

[0095] As an alkaline aqueous solution for development, solutions containing 0.1–5% by mass of sodium carbonate, 0.1–5% by mass of potassium carbonate, 0.1–5% by mass of sodium hydroxide, or 0.1–5% by mass of sodium tetraborate can be used. The pH of the alkaline aqueous solution can be in the range of 9–11, and its temperature can be adjusted according to the alkaline developability of the photosensitive layer. For example, a small amount of organic solvent, such as a surfactant, defoamer, or developer, can also be mixed into the alkaline aqueous solution.

[0096] Examples of organic solvents used in alkaline aqueous solutions include acetone, ethyl acetate, alkoxyethanol having alkoxy groups having 1 to 4 carbon atoms, ethanol, isopropanol, butanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether.

[0097] 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 ignition, water is added to these organic solvents in the range of 1 to 20% by mass to prepare the organic solvent developer.

[0098] The method for forming the resist pattern in this embodiment may also include the following steps: after removing the uncured portion in the developing process, heating at approximately 60–250°C or 0.2–10 J / cm² is performed as needed. 2 The exposure to the left and right sides further solidifies the resist pattern.

[0099] [Manufacturing method of wiring board] The method for manufacturing a wiring substrate according to this embodiment includes a step of etching or plating a substrate on which a resist pattern has been formed by the above-described resist pattern forming method to form a conductor pattern. It may also include other steps such as a resist pattern removal step as needed.

[0100] In etching, a resist pattern formed on a substrate is used as a mask to etch away a conductor layer disposed on the substrate to form a conductor pattern. The etching method can be appropriately selected depending on the conductor layer to be removed. Examples of etching solutions include copper chloride solution, ferric chloride solution, alkaline etching solution, and hydrogen peroxide-based etching solutions.

[0101] In the plating process, a resist pattern formed on the substrate is used as a mask to perform plating on a conductor layer disposed on the substrate. After plating, the resist can be removed by removing the resist pattern (described later), and the conductor layer covered by the resist can be further etched to form a conductor pattern. The plating process can be electrolytic plating or electroless plating, but electroless plating is preferred.

[0102] After etching or plating, the resist pattern on the substrate is removed. The resist pattern can be removed using, for example, an inorganic or organic alkali stripping solution. Examples of inorganic alkali stripping solutions include 1-10% by mass aqueous solutions of sodium hydroxide and potassium hydroxide. Examples of organic alkali stripping solutions include amine stripping solutions such as ethanolamine, ethylenediamine, and diethylenetriamine, as well as tetramethylammonium hydroxide aqueous solutions. From the viewpoint of the peelability of thick-film resist patterns, organic alkali stripping solutions can be used.

[0103] Methods for removing resist patterns include, for example, immersion and spraying, which can be used alone or in combination.

[0104] After the resist pattern is removed following the plating process, the resist-coated conductor layer can be further etched to form a conductor pattern, thereby manufacturing the desired printed circuit board. The etching method can be appropriately selected based on the conductor layer to be removed. For example, the etching solution described above can be used.

[0105] The wiring board manufacturing method described in this embodiment can be applied not only to the manufacturing of single-layer wiring boards but also to the manufacturing of multi-layer wiring boards, and also to the manufacturing of wiring boards with small-diameter through holes, etc.

[0106] Example The present invention will be further described in detail below through embodiments, but the present invention is not limited to these embodiments.

[0107] [Photosensitive Resin Composition] Photosensitive resin compositions were prepared by mixing the components shown in Table 1 at the amounts (parts by mass) shown in the table. Additionally, the amounts (parts by mass) of components other than the solvent shown in Table 1 represent the mass of non-volatile components (solid content). Details of each component shown in Table 1 are as follows.

[0108] ((A) ingredient) A-1: Ethylene glycol monomethyl ether / toluene solution (solid content: 47% by mass) of a copolymer of methacrylic acid / methyl methacrylate / styrene / benzyl methacrylate (mass ratio: 27 / 5 / 45 / 23, Mw: 47000, acid value: 176.1 mg KOH / g, Tg: 107℃). (Component B) b1-1: Dicyclopentyl acrylate (manufactured by Resonac Holdings Corporation, product name "FA-513AS") b1-2: Dicyclopentyl methacrylate (manufactured by Resonac Holdings Corporation, product name "FA-513M") b1-3: Isoborneol acrylate (manufactured by OSAKA ORGANIC CHEMICAL INDUSTRY LTD) b2-1: A 70% solution of propylene glycol monomethyl ether in 2,2-bis(4-(methacryloyloxyethoxy)phenyl)propane (average 10 mol of ethylene oxide adduct) (manufactured by Resonac Corporation, product name "FA-321M"). b2-2: Tricyclodecanedimethyl diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., product name "A-DCP") b2-3: Ethoxylated bisphenol A diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., product name "A-BPE-10") (C) component) BCIM: 2,2'-bis(o-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole (manufactured by Hampford Company) ((D) component) DBA: 9,10-Dibutoxyanthracene (manufactured by KAWASAKI KASEI CHEMICALS LTD.) (Other ingredients) Hydrogen donor: Colorless crystal violet (manufactured by YAMADA CHEMICAL CO., LTD.) Dye: Malachite Green (manufactured by OSAKA ORGANIC CHEMICAL INDUSTRY LTD.) [Photosensitive element] A 16 μm thick polyethylene terephthalate film (manufactured by TORAY INDUSTRIES, INC., trade name "FB-40") was prepared as a support. After coating the support with a photosensitive resin composition, it was dried sequentially in a hot air convection dryer at 80°C and 120°C to form a 40 μm thick photosensitive layer. A polyethylene film (manufactured by TAMAPOLY CO., LTD., product name "NF-15") was then laminated onto the photosensitive layer as a protective layer, resulting in a photosensitive element composed of a support, a photosensitive layer, and a protective layer stacked sequentially.

[0109] [Laminated body L1] A copper-clad laminate (manufactured by Resonac Corporation, product name: "MCL-E-67") comprising a glass epoxy material and copper foil (thickness: 16 μm) disposed on both sides of the glass epoxy material was pickled and washed, and then dried with an air stream. Next, the copper-clad laminate was heated to 80°C, and a photosensitive element was laminated onto the copper-clad laminate by peeling off the protective layer and bringing the photosensitive layer into contact with the copper surface, thereby obtaining a laminate L1 comprising a copper-clad laminate, a photosensitive layer, and a support in sequence. Lamination was performed using a 110°C hot roller at a pressing pressure of 0.4 MPa and a roller speed of 1.0 m / min.

[0110] [Layered body L2] For the Cu sputtered PET film (manufactured by GEOMATEC CO., LTD., thickness: 125 μm), the protective layer was peeled off and the photosensitive element was laminated in such a way that the photosensitive layer was brought into contact with the copper surface, thereby obtaining a laminate L2 comprising the Cu sputtered PET film, the photosensitive layer, and the support in sequence. Lamination was performed using a 110°C hot roller at a pressing pressure of 0.4 MPa and a roller speed of 1.0 m / min.

[0111] [evaluate] The following evaluation was performed using laminates L1 and L2. The results are shown in Table 2.

[0112] (Minimum development time) After cutting the laminate L1 into square shapes (5cm × 5cm), the support was peeled off, thus obtaining the test piece. Next, using a 1% (w / w) sodium carbonate aqueous solution at 30°C and a pressure of 0.18 MPa, the unexposed photosensitive layer in the test piece was spray-developed. The shortest time at which unexposed photosensitive layers larger than 1mm were visibly removed was defined as the minimum development time (MD). A fully conical nozzle was used in the spray development. The distance between the test piece and the nozzle tip was 6cm, with the center of the test piece aligned with the center of the nozzle. A shorter minimum development time (in seconds) indicates better developability.

[0113] (Sensitivity) After mounting a Hitachi 41-level staged exposure meter on the support of the laminate L1, the photosensitive layer was exposed using a direct-drawing exposure machine (manufactured by ORC MANUFACTURING CO.,LTD., product name "FDi-Ms") with a wavelength of 405nm blue-violet laser diode as the light source, at an exposure level (irradiation energy) of 15 levels (the remaining number of stages of the Hitachi 41-level staged exposure meter) through the support. The exposure level at this time (unit: mJ / cm²) is recorded. 2 The sensitivity (light sensitivity) was evaluated. The lower the exposure, the higher the sensitivity.

[0114] (Seamless fit) Using a drawing pattern with a line width (L) / space width (S) of x / 3x (x = 3 to 30, unit: μm, 1 μm interval), the photosensitive layer of the stack L1 was exposed using a direct-write exposure machine (FDi-Ms) with a residual number of 15 exposure levels from the Hitachi 41-level staged exposure meter.

[0115] (Resolution) Using a drawing pattern with a line width (L) / space width (S) of 3x / x (x = 3 to 30, unit: μm, 1 μm interval), the photosensitive layer of the stack L1 was exposed using a direct-write exposure machine (FDi-Ms) with a residual level of 15 levels from the Hitachi 41-level staged exposure meter.

[0116] After exposure, the support was peeled off from the laminate L1 to expose the photosensitive layer. Unexposed areas were removed by spraying a 1% sodium carbonate aqueous solution at 30°C for twice the minimum development time. After development, resolution was evaluated by the minimum spacing (in μm) of the resist pattern formed where the voids (unexposed areas) were removed without residue and the lines (exposed areas) were free of bends and defects. Adhesion was evaluated by the minimum line width (in μm) of the resist pattern. For both resolution and adhesion, smaller values ​​indicate better performance.

[0117] (Circular aperture resolution) Using a through-hole pattern (via pattern) with a diameter of the circular aperture / center-to-center distance of the circular apertures of x / 1.5x (x=10~50, unit: μm, 1μm interval), the photosensitive layer of the stack L2 was exposed using a direct-write exposure machine (FDi-Ms) with an exposure level of 15 levels based on the remaining level of the Hitachi 41-level stage exposure meter.

[0118] After exposure, the support was peeled off from the laminate L2 to expose the photosensitive layer. Unexposed areas were removed by spraying a 1% sodium carbonate aqueous solution at 30°C for twice the minimum development time. The resulting via pattern was observed using an optical microscope. The circular aperture resolution was evaluated based on the diameter of the smallest via pattern that was cleanly and completely removed (opened) within the grid-like arrangement. A smaller value indicates better circular aperture resolution.

[0119] (Peelability) On the support of the laminate L1, a glass chrome type exposure tool (an exposure tool with a 45mm×60mm planar pattern) was used as a negative for peel test evaluation, and a direct tracing exposure machine (FDi-Ms) was used to expose the photosensitive layer through the support with an exposure level of 15 levels, which was the residual level of the Hitachi 41-level stage exposure table.

[0120] After exposure, the support was peeled off from the laminate L1 to expose the photosensitive layer. Unexposed areas were removed by spraying a 1% (w / w) sodium carbonate aqueous solution at 30°C for twice the minimum development time, resulting in a substrate with a cured film. After the substrate was left at room temperature for 3 hours, it was immersed in an amine-based stripping solution heated to 50°C (6% (v / v) R-100S + 2% (v / v) R-101 aqueous solution, manufactured by MITSUBISHI GAS CHEMICAL COMPANY, INC.) and stirred at 400 rpm. The time from the start of stirring to the complete removal of the cured film from the substrate is defined as the stripping time (in seconds). A shorter stripping time indicates better peelability.

[0121] [Table 1]

[0122] [Table 2]

[0123] Symbol Explanation 1-Photosensitive element, 2-Support, 3-Photosensitive layer, 4-Protective layer.

Claims

1. A photosensitive resin composition comprising a binder polymer, a photopolymerizable compound, a photoinitiator, and a sensitizer, wherein the photosensitive resin composition, The photopolymerizable compound comprises a monofunctional (meth)acrylate having a bicyclic backbone. The content of the monofunctional (meth)acrylate having a bicyclic backbone is less than 5.0 parts by mass relative to the total amount of the adhesive polymer and the photopolymerizable compound (100 parts by mass).

2. The photosensitive resin composition according to claim 1, wherein, The content of the monofunctional (meth)acrylate with a bicyclic backbone is 1.0 to 4.5 parts by mass relative to the total amount of the adhesive polymer and the photopolymerizable compound (100 parts by mass).

3. The photosensitive resin composition according to claim 1, wherein, The photopolymerizable compound further comprises bisphenol A type (meth)acrylate.

4. The photosensitive resin composition according to claim 1, wherein, The sensitizer comprises anthracene compounds.

5. A photosensitive element comprising a support and a photosensitive layer formed on the support using the photosensitive resin composition according to any one of claims 1 to 4.

6. The photosensitive element according to claim 5, wherein, The thickness of the photosensitive layer is 30 μm or more.

7. A method for forming a resist pattern, comprising: The process of forming a photosensitive layer on a substrate using the photosensitive element as described in claim 6; The process of irradiating at least a portion of the photosensitive layer with active light to form a photocurable portion; and The process of removing the uncured portion of the photosensitive layer from the substrate to form a resist pattern.

8. A method for manufacturing a wiring substrate, comprising a step of etching or plating a substrate having a resist pattern formed by the resist pattern forming method of claim 7 to form a conductor pattern.

9. The method for manufacturing a wiring substrate according to claim 8, further comprising a step of removing the resist pattern using an organic alkali stripping solution after the etching or plating process.

Images