Photosensitive resin composition, photosensitive element, method for forming resist pattern, and method for producing printed wiring board

Abstract

A photosensitive resin composition according to one embodiment of the present invention contains a binder polymer, a photopolymerizable compound, a photopolymerization initiator, and a sensitizer, and is characterized in that: the binder polymer has a structural unit derived from acrylic acid and a structural unit derived from styrene or a styrene derivative; the light absorbance per 1 [mu] m thickness of the photosensitive resin composition with respect to light having a wavelength of 365 nm is 0.0030-0.0120.

Description

Technical Field

[0001] The present invention relates to a photosensitive resin composition, a photosensitive element, a method for forming a resist pattern, and a method for manufacturing a printed wiring board. Background Art

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

[0003] A printed wiring board is manufactured using the above photosensitive element, for example, according to the following steps. That is, first, the photosensitive layer of the photosensitive element is laminated on a circuit formation substrate such as a copper-clad laminate. Next, the photosensitive layer is exposed through a mask or the like to form a photocured portion. At this time, the support film is peeled off before or after the exposure. Then, the area other than the photocured portion of the photosensitive layer is removed with a developer to form a resist pattern. Next, the resist pattern is used as a resist, and an etching treatment or a plating treatment is performed to form a conductor pattern, and finally, the photocured portion (resist pattern) of the photosensitive layer is peeled off (removed).

[0004] With the progress of the high density and miniaturization of conductor patterns of printed wiring boards, the contact area between the circuit formation substrate and the photosensitive layer as a resist becomes smaller. Therefore, excellent characteristics during etching treatment or plating treatment are required for the photosensitive layer, and excellent adhesion to the circuit formation substrate and excellent resolution during formation of the resist pattern are also required (for example, refer to Patent Documents 1 and 2).

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Laid-Open No. 2009-003177

[0008] Patent Document 2: Japanese Patent Laid-Open No. 2013-195712 Summary of the Invention

[0009] Technical Problem to be Solved by the Invention

[0010] With the high performance of semiconductor packages, the smoothing of substrates has been continuously developed, and it is required that the photosensitive resin composition forms a resist pattern having high adhesion to a smooth substrate with a surface roughness (Ra) of 200 nm or less. On the other hand, the development time of the photosensitive layer and the peeling time of the resist pattern of the photosensitive resin composition with excellent adhesion tend to become long. From the viewpoint of improving productivity, it is desired to shorten the development time and peeling time of the photosensitive resin composition.

[0011] An object of the present invention is to provide a photosensitive resin composition, a photosensitive element, a method for forming a resist pattern, and a method for manufacturing a printed wiring board, which have excellent developability, adhesion, and peelability.

[0012] Means for Solving the Technical Problem

[0013] In order to solve the above problems, the present inventors have found a photosensitive resin composition that can form a resist pattern with excellent adhesion to a smooth substrate and can shorten the development time of the photosensitive layer and the peel time of the resist pattern by using a binder polymer having a specific composition and setting the absorbance within a specific range. One aspect of the present invention relates to the following photosensitive resin composition, photosensitive element, method for forming a resist pattern, and method for manufacturing a printed wiring board.

[0014] [1] A photosensitive resin composition containing a binder polymer, a photopolymerizable compound, a photoinitiator, and a sensitizer, wherein the binder polymer has a structural unit derived from acrylic acid and a structural unit derived from styrene or a styrene derivative, and the absorbance of the photosensitive resin composition per 1 μm thickness with respect to light of wavelength 365 nm is 0.0030 to 0.0120.

[0015] [2] The photosensitive resin composition according to the above [1], wherein the sensitizer contains a pyrazoline compound or a dialkylaminobenzophenone compound.

[0016] [3] The photosensitive resin composition according to the above [1] or [2], wherein the weight average molecular weight of the binder polymer is 10,000 to 60,000.

[0017] [4] The photosensitive resin composition according to any one of the above [1] to [3], wherein the acid value of the binder polymer is 140 to 200 mgKOH / g.

[0018] [5] The photosensitive resin composition according to any one of the above [1] to [4], wherein, based on the total mass of the structural units derived from the polymerizable monomers constituting the binder polymer, the content of the structural units derived from styrene or a styrene derivative is 50 to 85% by mass.

[0019] [6] 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 [5].

[0020] [7] A method for forming a resist pattern, comprising: a step of forming a photosensitive layer on a substrate having a surface roughness of 200 nm or less using the photosensitive resin composition described in any one of [1] to [5] above or the photosensitive element described in [6] above; a step of irradiating at least a part of the photosensitive layer with actinic rays to form a photocured part; and a step of removing the uncured part of the photosensitive layer from the substrate to form a resist pattern.

[0021] [8] A method for manufacturing a printed wiring board, comprising a step of forming a conductor pattern by performing an etching treatment or a plating treatment on a substrate having a resist pattern formed by the method for forming a resist pattern described in [7] above.

[0022] [9] The method for manufacturing a printed wiring board according to [8] above, further comprising a step of removing the resist pattern after the etching treatment or the plating treatment.

[0023] Advantages of the Invention

[0024] According to the present invention, it is possible to provide a photosensitive resin composition, a photosensitive element, a method for forming a resist pattern, and a method for manufacturing a printed wiring board, which are excellent in developability, adhesion, and peelability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic cross-sectional view showing an embodiment of the photosensitive element. DETAILED DESCRIPTION OF THE INVENTION

[0026] In this specification, the term "step" includes not only an independent step, but also, even in a case where it cannot be clearly distinguished from other steps, as long as the intended function of the step is achieved, it is also included in this term. Regarding the term "layer", when observed in a plan view, in addition to a structure having a shape formed on the entire surface, it also includes a structure having a shape formed on a part. The numerical range represented by "~" means a range including the numerical values described before and after "~" as the minimum value and the maximum value, respectively. In the numerical ranges gradually described in this specification, the upper limit value or the lower limit value of the numerical range at any stage can also be replaced with the upper limit value or the lower limit value of the numerical range at other stages. In the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range can also be replaced with the value shown in the examples.

[0027] 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.

[0028] In this specification, regarding the amounts of the respective components in the photosensitive resin composition, when there are multiple substances belonging to each component in the composition, unless otherwise specified, it refers to the total amount of the multiple substances present in the composition. In this specification, the so-called "solid component" refers to the non-volatile components in the photosensitive resin composition other than the volatile substances (such as water, solvents, etc.). That is, the so-called "solid component" refers to the components other than the solvents that do not volatilize and remain during the drying of the photosensitive resin composition described later, and also includes components that are liquid, syrupy, or waxy at room temperature (25°C).

[0029] [Photosensitive Resin Composition]

[0030] The photosensitive resin composition according to this embodiment contains (A) an adhesive polymer (hereinafter, sometimes referred to as "(A) component"), (B) a photopolymerizable compound (hereinafter, sometimes referred to as "(B) component"), (C) a photoinitiator (hereinafter, sometimes referred to as "(C) component"), and (D) a sensitizer (hereinafter, sometimes referred to as "(D) component"). The above adhesive polymer has a structural unit derived from acrylic acid and a structural unit derived from styrene or a styrene derivative. The absorbance of the photosensitive resin composition per 1 μm thickness with respect to light of wavelength 365 nm is 0.0030 to 0.0120. The absorbance of the photosensitive resin composition per 1 μm thickness with respect to light of wavelength 365 nm refers to the absorbance of the photosensitive layer formed using the photosensitive resin composition per 1 μm thickness with respect to light of wavelength 365 nm.

[0031] The photosensitive resin composition of this embodiment contains the above (A) to (D) components as essential components. By having an absorbance of 0.0030 to 0.0120 per 1 μm thickness with respect to light of wavelength 365 nm, a resist pattern with a good resist shape can be formed, and good resolution and adhesion can be obtained. Hereinafter, each component that the photosensitive resin composition may contain will be described in detail.

[0032] ((A) Component: Adhesive Polymer)

[0033] The photosensitive resin composition according to this embodiment can improve the developability, resolution, adhesion, and peelability of the photosensitive layer formed from the photosensitive resin composition by containing an adhesive polymer having a specific structure as the (A) component.

[0034] The (A) component can be produced by subjecting a polymerizable monomer containing acrylic acid and styrene or a styrene derivative to radical polymerization.

[0035] By making the component (A) have a structural unit derived from acrylic acid, the alkali developability of the photosensitive resin composition can be improved, and the peelability of the resist pattern can be enhanced. Acrylic acid and methacrylic acid can be used simultaneously, but if the content of the structural unit derived from methacrylic acid is increased, the peelability tends to decrease.

[0036] From the viewpoint of further shortening the development time, based on the total mass of the structural units derived from the polymerizable monomers constituting the binder polymer (100% by mass), the content of the structural unit derived from acrylic acid in the component (A) is preferably 15% by mass or more, and can also be 16% or more, 17% by mass or more, 18% by mass or more, or 20% by mass or more. From the viewpoint of further improving the adhesion, the content of the structural unit derived from acrylic acid is preferably 26% by mass or less, and can also be 25% by mass or less, 24% by mass or less, or 23% by mass or less. From the viewpoint of improving the developability and adhesion in a balanced manner, the content of the structural unit derived from acrylic acid can be 15 to 26% by mass, 16 to 25% by mass, 17 to 24% by mass, 18 to 24% by mass, or 20 to 23% by mass.

[0037] (A) By having a structural unit derived from styrene or a styrene derivative (hereinafter, also referred to as "styrenic structural unit"), the resolution and adhesion of the photosensitive resin composition can be improved. Examples of the styrene derivative include vinyltoluene, α-methylstyrene, p-methylstyrene, and p-ethylstyrene.

[0038] From the viewpoint of further improving the adhesion, based on the total mass of the structural units derived from the polymerizable monomers constituting the binder polymer, the content of the styrenic structural unit in the component (A) can be 50% by mass or more, 55% by mass or more, 60% by mass or more, or 65% by mass or more. From the viewpoint of further shortening the peeling time, the content of the styrenic structural unit can be 85% by mass or less, 84% by mass or less, 83% by mass or less, or 80% by mass or less. From the viewpoint of improving the adhesion and peelability in a balanced manner, the content of the styrenic structural unit can be 50 to 85% by mass, 55 to 84% by mass, 60 to 83% by mass, or 65 to 80% by mass.

[0039] (A) The component may further have a structural unit derived from a (meth)acrylate compound having an alicyclic structure. By having a structural unit derived from a (meth)acrylate compound having an alicyclic structure, the resolution and adhesion of the photosensitive resin composition can be improved. Examples of the (meth)acrylate having an alicyclic structure include cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, cyclopentyl (meth)acrylate, and dicyclopentyl (meth)acrylate.

[0040] Regarding the content of the structural unit derived from the (meth)acrylate compound having an alicyclic structure, based on the total mass of the structural units derived from the polymerizable monomers constituting the binder polymer (100% by mass), from the viewpoint of further improving the developability and adhesion of the photosensitive resin composition, it may be 1% by mass or more, 2% by mass or more, or 4% by mass or more, and from the viewpoint of further improving the developability of the photosensitive resin composition, it may be 15% by mass or less, 10% by mass or less, or 8% by mass or less.

[0041] The component (A) may further contain a structural unit derived from a polymerizable monomer other than the above (hereinafter, also referred to as "other monomers"). Examples of other monomers include methacrylic acid, 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, benzyl (meth)acrylate or its derivatives, furfuryl (meth)acrylate, 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, β-furyl (meth)acrylate, β-styryl (meth)acrylate, maleic acid, maleic anhydride, monoalkyl maleate, fumaric acid, cinnamic acid, α-cyanocinnamic acid, itaconic acid, crotonic acid, and propiolic acid. These can be used alone or in combination of two or more.

[0042] The weight average molecular weight (Mw) of the component (A) may be 10,000 to 60,000, 15,000 to 55,000, 20,000 to 50,000, or 23,000 to 45,000. If Mw is 60,000 or less, there is a tendency for further improvement in developability and developability, and if Mw is 10,000 or more, there is a tendency for the loss of the resist pattern and difficulty in peeling. The dispersity (Mw / Mn) of the component (A) may be 1.0 to 3.0, 1.0 to 2.5, or 1.0 to 2.3. If the dispersity becomes smaller, there is a tendency for improvement in developability.

[0043] The weight average molecular weight and the dispersity can be measured, for example, by gel permeation chromatography (GPC) using a calibration curve of standard polystyrene. More specifically, it can be measured under the conditions described in the examples.

[0044] From the viewpoint of achieving both developability and peelability, the acid value of component (A) can be 140 to 200 mgKOH / g, 150 to 190 mgKOH / g, 160 to 180 mgKOH / g, or 165 to 175 mgKOH / g. When the acid value of component (A) is 140 mgKOH / g or more, it is easier to further shorten the development time, and when it is 200 mgKOH / g or less, it is easier to further improve the adhesion. The acid value of component (A) can be adjusted by the structural unit derived from acrylic acid. The acid value of component (A) can be measured in accordance with JIS K6901:2008 5.3.2.

[0045] From the viewpoint of excellent film formability, the content of component (A) can be 20 parts by mass or more, 30 parts by mass or more, 40 parts by mass or more, 45 parts by mass or more, or 50 parts by mass or more with respect to 100 parts by mass of the total amount of component (A) and component (B). From the viewpoint of further improving sensitivity and resolution, it can be 80 parts by mass or less, 70 parts by mass or less, 65 parts by mass or less, or 60 parts by mass or less.

[0046] (Component (B): Photopolymerizable compound)

[0047] As component (B), there is no particular limitation as long as it is a photopolymerizable compound having at least one ethylenically unsaturated bond. From the viewpoint of improving alkali developability, resolution, and peel characteristics after curing, component (B) preferably contains at least one bisphenol type (meth)acrylate, and more preferably contains bisphenol A type (meth)acrylate among bisphenol type (meth)acrylates.

[0048] Examples of bisphenol A type (meth)acrylate 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. Among them, from the viewpoint of further improving resolution and peel characteristics, 2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane is preferred.

[0049] As 2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane, a compound having 10 or more oxyethylene groups, a compound having less than 10 oxyethylene groups, or both a compound having 10 or more oxyethylene groups and a compound having less than 10 oxyethylene groups can be used.

[0050] As commercially available bisphenol A type (meth)acrylate, for example, as 2,2-bis(4-((meth)acryloyloxy dipropoxy)phenyl)propane, BPE-200 (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name) can be cited. As ethoxylated bisphenol A dimethacrylate, BP-2EM (manufactured by Kyoeisha Chemical Co., Ltd., trade name) can be cited. As 2,2-bis(4-(methacryloyloxy pentaethoxy)phenyl)propane, BPE-500 (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name) and FA-321M (manufactured by Showa Denko Materials Co., Ltd., trade name) can be cited. These bisphenol A type (meth)acrylates can be used alone or in combination of two or more.

[0051] Based on the total amount of component (B), the content of bisphenol type (meth)acrylate can be 40 to 98% by mass, 50 to 97% by mass, 60 to 95% by mass, or 70 to 90% by mass. When the content is 40% by mass or more, the developability, adhesion, and inhibition of generation at the bottom of the resist become better. When it is 98% by mass or less, the development time is appropriately shortened, and it is more difficult to generate development residues.

[0052] As component (B) other than bisphenol type (meth)acrylate, from the viewpoint of improving the flexibility of the cured product (cured film), at least one kind of polyalkylene glycol di(meth)acrylate having at least one of (poly)oxyethylene chain and (poly)oxypropylene chain in the molecule can be further included, and polyalkylene glycol di(meth)acrylate having both (poly)oxyethylene chain and (poly)oxypropylene chain in the molecule can be further included. From the viewpoint of further improving the adhesion and developability, the total number of oxyethylene (EO group) and / or oxypropylene (PO group) in the polyalkylene glycol di(meth)acrylate can be 2 to 40, 4 to 30, or 6 to 20.

[0053] As polyalkylene glycol di(meth)acrylate, for example, FA-023M (manufactured by Showa Denko Materials Co., Ltd., trade name), FA-024M (manufactured by Showa Denko Materials Co., Ltd., trade name), and NK ester HEMA-9P (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name) can be cited. These can be used alone or in combination of two or more.

[0054] Based on the total amount of component (B), the content of the polyalkylene glycol di(meth)acrylate may be 2 to 40% by mass, 3 to 30% by mass, or 5 to 20% by mass.

[0055] As component (B) other than the above, nonylphenoxy polyethyleneoxy acrylate, phthalic acid compounds, polyol (meth)acrylates, alkyl (meth)acrylates, etc. may also be used. Among them, from the viewpoint of evenly improving the developability, adhesiveness, resist shape, and peeling characteristics after curing, component (B) may contain at least one selected from nonylphenoxy polyethyleneoxy acrylate and phthalic acid compounds. However, since the refractive index of these compounds is relatively low, from the viewpoint of improving the developability, based on the total amount of component (B), the content may be 5 to 50% by mass, 5 to 40% by mass, or 10 to 30% by mass.

[0056] Examples of nonylphenoxy polyethyleneoxy acrylate include nonylphenoxy triethyleneoxy acrylate, nonylphenoxy tetraethyleneoxy acrylate, nonylphenoxy pentaethyleneoxy acrylate, nonylphenoxy hexaethyleneoxy acrylate, nonylphenoxy heptaethyleneoxy acrylate, nonylphenoxy octaethyleneoxy acrylate, nonylphenoxy nonaethyleneoxy acrylate, nonylphenoxy decaethyleneoxy acrylate, and nonylphenoxy undecaethyleneoxy acrylate.

[0057] Examples of phthalic acid compounds include γ-chloro-β-hydroxypropyl-β'-(meth)acryloyloxyethyl phthalate, β-hydroxyethyl-β'-(meth)acryloyloxyethyl phthalate, and β-hydroxypropyl-β'-(meth)acryloyloxyethyl phthalate. γ-chloro-β-hydroxypropyl-β'-methacryloyloxyethyl phthalate is commercially available as FA-MECH (manufactured by Showa Denko Materials Co., Ltd., trade name).

[0058] From the viewpoints of improving sensitivity and reducing tailing, the component (B) may contain a (meth)acrylic polyol ester. Examples of the (meth)acrylic polyol ester include trimethylolpropane polyethoxy tri(meth)acrylate, trimethylolpropane polypropoxy tri(meth)acrylate, trimethylolpropane polybutoxy tri(meth)acrylate, trimethylolpropane polyethoxy polypropoxy tri(meth)acrylate, trimethylolethane polyethoxy tri(meth)acrylate, trimethylolethane polypropoxy tri(meth)acrylate, trimethylolethane polybutoxy tri(meth)acrylate, trimethylolethane polyethoxy polypropoxy tri(meth)acrylate, pentaerythritol polyethoxy tri(meth)acrylate, pentaerythritol polypropoxy tri(meth)acrylate, pentaerythritol polybutoxy tri(meth)acrylate, pentaerythritol polyethoxy polypropoxy tri(meth)acrylate, glycerol polyethoxy tri(meth)acrylate, glycerol polypropoxy tri(meth)acrylate, glycerol polybutoxy tri(meth)acrylate, and glycerol polyethoxy polypropoxy tri(meth)acrylate.

[0059] With respect to 100 parts by mass of the total amount of the component (A) and the component (B), the content of the component (B) is preferably 20 to 60 parts by mass, more preferably 30 to 55 parts by mass, and still more preferably 35 to 50 parts by mass. If the content of the component (B) is within this range, in addition to the developability and adhesion of the photosensitive resin composition, the photosensitivity and the film formability also become better.

[0060] ((Component (C): Photoinitiator))

[0061] As the component (C), as long as it is a component capable of polymerizing the component (B), there is no particular limitation, and it can be appropriately selected from commonly used photoinitiators.

[0062] Examples of the component (C) include hexaarylbiimidazole compounds; aromatic ketone compounds such as benzophenone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-acetone-1; quinone compounds such as alkyl anthraquinone; benzoin ether compounds such as benzoin alkyl ether; benzoin compounds such as benzoin and alkyl benzoin; benzyl derivatives such as benzyl dimethyl ketal; and phosphine oxide compounds such as bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,6-dimethylbenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, and (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide.

[0063] From the viewpoint of improving the adhesion between the photosensitive layer and the smooth substrate, the component (C) may contain a hexaarylbiimidazole compound. The aryl group in the hexaarylbiimidazole compound may be a phenyl group or the like. The hydrogen atom bonded to the aryl group in the hexaarylbiimidazole compound may be substituted with a halogen atom (such as a chlorine atom).

[0064] The hexaarylbiimidazole compound may be a 2,4,5-triaryl imidazole dimer. As the 2,4,5-triaryl imidazole dimer, for example, 2-(o-chlorophenyl)-4,5-diphenyl imidazole dimer, 2-(o-chlorophenyl)-4,5-bis-(m-methoxyphenyl) imidazole dimer, and 2-(p-methoxyphenyl)-4,5-diphenyl imidazole dimer can be cited.

[0065] By adjusting the content of the component (C), the absorbance of the photosensitive resin composition per 1 μm thickness with respect to light having a wavelength of 365 nm is made 0.0030 or more, and the deterioration of the resolution can be suppressed. By making the absorbance of the photosensitive resin composition per 1 μm thickness with respect to light having a wavelength of 365 nm 0.0120 or less, the developability and adhesion can be improved.

[0066] With respect to 100 parts by mass of the total amount of the components (A) and (B), the content of the component (C) may be 1.0 to 10 parts by mass, 2.0 to 8 parts by mass, 3.0 to 7.0 parts by mass, or 4.0 to 6.0 parts by mass. If the content of the component (C) is within this range, it becomes easy to improve both the photosensitivity and the developability in a well-balanced manner.

[0067] ((D) component: sensitizer)

[0068] The photosensitive resin composition according to this embodiment can effectively utilize the absorption wavelength of the actinic rays used in exposure by containing the component (D).

[0069] As the component (D), for example, a dialkylaminobenzophenone compound, a pyrazoline compound, an anthracene compound, a coumarin compound, a xanthone compound, a thioxanthone compound, an oxazole compound, a benzoxazole compound, a thiazole compound, a benzothiazole compound, a triazole compound, a stilbene compound, a triazine compound, a thiophene compound, a naphthalenedicarboximide compound, a triarylamine compound, and an aminoacridine compound can be cited. From the viewpoint of further improving the developability and adhesion, the component (D) may contain a pyrazoline compound or a dialkylaminobenzophenone compound.

[0070] As pyrazoline compounds, for example, 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-isopropylstyryl)-pyrazoline, 1-(4-methoxyphenyl)-3-(4-tert-butyl-styrene)-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-styrene)-5-(4-tert-butyl-phenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(4-isopropyl-styrene)-5-(4-isopropyl-phenyl)-pyrazoline, 1-(4-methoxyphenyl)-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-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butylphenyl)-3-(3,4-dimethoxystyryl)-5-(3,4-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butylphenyl)-3-(2,6-dimethoxystyryl)-5-(2,6-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butylphenyl)-3-(2,5-dimethoxystyryl)-5-(2,5-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butylphenyl)-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butylphenyl)-3-(2,4-dimethoxystyryl)-5-(2,4-dimethoxyphenyl)-pyrazoline, 1-(4-isopropylphenyl)-3-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)-pyrazoline, 1-(4-isopropylphenyl)-3-(3,4-dimethoxystyryl)-5-(3,4-dimethoxyphenyl)-pyrazoline, 1-(4-isopropylphenyl)-3-(2,6-dimethoxystyryl)-5-(2,6-dimethoxyphenyl)-pyrazoline, 1-(4-isopropylphenyl)-3-(2,5-dimethoxystyryl)-5-(2,5-dimethoxyphenyl)-pyrazoline, 1-(4-isopropylphenyl)-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)-pyrazoline, and 1-(4-isopropylphenyl)-3-(2,4-dimethoxystyryl)-5-(2,4-dimethoxyphenyl)-pyrazoline.,

[0071] Examples of the dialkylaminobenzophenone compound include 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, and 4-benzoyl-4'-methyldiphenyl sulfide.

[0072] By adjusting the content of the component (D), the absorbance of the photosensitive resin composition per 1 μm thickness with respect to light of wavelength 365 nm is made 0.0030 or more, and deterioration of resolution can be suppressed. By making the absorbance of the photosensitive resin composition per 1 μm thickness with respect to light of wavelength 365 nm 0.0120 or less, developability and adhesiveness can be improved.

[0073] From the viewpoint of further improving the adhesion, the content of the (D) component can be 1.60 parts by mass or less, 1.50 parts by mass or less, 1.40 parts by mass or less, or 1.35 parts by mass or less relative to 100 parts by mass of the (C) component. From the viewpoint of improving the developability, adhesion, and peelability in a balanced manner, the content of the (D) component can be 0.15 to 1.60 parts by mass, 0.20 to 1.50 parts by mass, 0.25 to 1.40 parts by mass, or 0.30 to 1.35 parts by mass relative to 100 parts by mass of the (C) component.

[0074] From the viewpoint of improving the photosensitivity and resolution, the content of the (D) component can be 0.01 to 0.10 parts by mass, 0.01 to 0.09 parts by mass, or 0.01 to 0.08 parts by mass relative to 100 parts by mass of the total amount of the (A) component and the (B) component.

[0075] ((E) component: polymerization inhibitor)

[0076] From the viewpoint of suppressing the polymerization of the unexposed portion during the formation of the resist pattern and further improving the resolution, the photosensitive resin composition may further contain a polymerization inhibitor as the (E) component. Examples of the polymerization inhibitor include 4-tert-butylcatechol and 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl.

[0077] The content of the (E) component can be 0.001 to 0.10 parts by mass, 0.005 to 0.08 parts by mass, or 0.01 to 0.06 parts by mass relative to 100 parts by mass of the total amount of the (A) component and the (B) component.

[0078] (Other components)

[0079] The photosensitive resin composition may further contain one or two or more other components in addition to the above components. Examples of the other components include hydrogen donors (bis[4-(dimethylamino)phenyl]methane, bis[4-(diethylamino)phenyl]methane, crystal violet, N-phenylglycine, etc.), dyes (malachite green, etc.), tribromophenyl sulfone, photochromogenic agents, thermal chromogenic inhibitors, plasticizers (p-toluenesulfonamide, etc.), pigments, fillers, defoamers, flame retardants, stabilizers, adhesion imparting agents, leveling agents, peel promoting agents, antioxidants, fragrances, imaging agents, thermal crosslinking agents, etc. The content of the other components can be 0.005 parts by mass or more or 0.01 parts by mass or more, and can also be 20 parts by mass or less relative to 100 parts by mass of the total amount of the (A) component and the (B) component.

[0080] The photosensitive resin composition may contain an organic solvent in order to improve the processability of the photosensitive composition or to adjust the viscosity and storage stability. As the organic solvent, commonly used organic solvents can be used without particular limitation. Examples of the organic solvent include methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N,N-dimethylformamide, propylene glycol monomethyl ether, and mixed solvents thereof. For example, the components (A) to (D) can be dissolved in an organic solvent and used as a solution having a solid content of about 30 to 60% by mass (hereinafter, referred to as "coating solution"). In addition, the solid content refers to the remaining components obtained by removing volatile components from the solution of the photosensitive resin composition.

[0081] The absorbance of the photosensitive resin composition of the present embodiment at a wavelength of 365 nm per 1 μm thickness is 0.0030 to 0.0120. By the absorbance being 0.0030 or more, a decrease in resolution can be suppressed. And by making the absorbance 0.0120 or less, the resolution and adhesion are improved. Regarding the above absorbance, from the viewpoint of further suppressing the decrease in resolution, it can be 0.0040 or more, 0.0050 or more, 0.0055 or more, or 0.0060 or more, and from the viewpoint of further improving the resolution and adhesion, it can be 0.0115 or less, 0.0110 or less, 0.0100 or less, or 0.0095 or less.

[0082] The absorbance of the photosensitive resin composition can be appropriately adjusted by the types and contents of the above components (A) to (D) and other components.

[0083] Regarding the absorbance of the photosensitive resin composition, a photosensitive layer is formed by forming the photosensitive resin composition into a film, and the absorbance of the photosensitive layer can be measured using an ultraviolet-visible spectrophotometer such as a U-3310 type spectrophotometer (manufactured by Hitachi High-Tech Corporation) to measure the absorbance of light at a wavelength of 365 nm. The absorbance per 1 μm thickness of the photosensitive resin composition can be obtained by dividing the absorbance measured for the photosensitive layer by the thickness of the photosensitive layer (unit: μm).

[0084] [Photosensitive Element]

[0085] The photosensitive element of the present embodiment includes a support and a photosensitive layer formed on the support, and the photosensitive layer contains the above photosensitive resin composition. When using the photosensitive element according to the present embodiment, after laminating the photosensitive layer on a substrate, exposure can be performed without peeling off the support (support film).

[0086] Figure 1 is a schematic cross-sectional view of a photosensitive element according to an embodiment. AsFigure 1 As shown, the photosensitive element 1 includes a support 2, a photosensitive layer 3 formed on the support 2 from the above photosensitive resin composition, and other layers such as a protective layer 4 provided as needed.

[0087] The support 2 and the protective layer 4 can each be a polymer film having heat resistance and solvent resistance. For example, they can be polyester films such as polyethylene terephthalate films, polyolefin films such as polyethylene films and polypropylene films. The support 2 and the protective layer 4 can each be a film of a hydrocarbon-based polymer other than polyolefins. The film of the hydrocarbon-based polymer containing polyolefins can be of low density. For example, it can have a density of 1.014 g / cm 3 or less. The support 2 and the protective layer 4 can each be a stretched film formed by stretching the low-density hydrocarbon-based polymer film. The type of the polymer film constituting the protective layer 4 can be the same as or different from the type of the polymer film constituting the support 2.

[0088] These polymer films can be purchased respectively 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 manufactured by OJI PAPER CO., LTD. (e.g., ALPHAN MA-410, E-200C), SHIN-ETSU FILM CO., LTD., etc.

[0089] From the viewpoint of being able to suppress breakage of the support 2 when the support 2 is peeled from the photosensitive layer 3, the thickness of the support 2 can be 1 μm or more or 5 μm or more. From the viewpoint of being able to perform exposure appropriately even when exposing through the support 2, it can be 100 μm or less, 50 μm or less, or 30 μm or less.

[0090] From the viewpoint of being able to suppress breakage of the protective layer 4 when the protective layer 4 is peeled and the photosensitive layer 3 and the support 2 are laminated on a 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.

[0091] The photosensitive layer 3 is composed of the above photosensitive resin composition. Regarding the thickness of the photosensitive layer 3 after drying (when the photosensitive resin composition contains an organic solvent, after the organic solvent has volatilized), from the viewpoints of easy coating and improved productivity, it can be 1 μm or more, 5 μm or more, 10 μm or more, or 15 μm or more. From the viewpoints of further improving adhesion and resolution, it can be 100 μm or less, 50 μm or less, 40 μm or less, 35 μm or less, or 30 μm or less.

[0092] Since the photosensitive layer in the photosensitive element is a layer formed using the above photosensitive resin composition, the absorbance of each 1 μm thickness with respect to light of wavelength 365 nm can be 0.0030 to 0.0120. By having the absorbance be 0.0030 or more, a decrease in resolution can be suppressed. Also, by making the absorbance 0.0120 or less, the resolution and adhesion are improved. Regarding the above absorbance, from the viewpoint of further suppressing the decrease in resolution, it can be 0.0040 or more, 0.0050 or more, 0.0055 or more, or 0.0060 or more, and from the viewpoint of further improving the resolution and adhesion, it can be 0.0115 or less, 0.0110 or less, 0.0100 or less, or 0.0095 or less. The method for measuring the absorbance of the photosensitive layer is as described above.

[0093] The photosensitive element 1 can be obtained, for example, as follows. First, a photosensitive layer 3 is formed on a 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.

[0094] The coating layer is formed by a known method such as roll coating, comma coating, gravure coating, air knife coating, die coating, bar coating, etc. Drying of the coating layer is performed so that the amount of the organic solvent remaining in the photosensitive layer 3 becomes, for example, 2% by mass or less. Specifically, for example, it is performed at 70 to 150 °C for about 5 to 30 minutes.

[0095] The photosensitive element may further have an intermediate layer between the support 2 and the photosensitive layer 3. The intermediate layer can be a layer containing a water-soluble resin. As the water-soluble resin, for example, a resin containing polyvinyl alcohol as a main component can be cited.

[0096] In another embodiment, the photosensitive element may not have a protective layer, or may further have other layers such as a buffer layer, an adhesive layer, a light absorption layer, a gas barrier layer, etc.

[0097] The photosensitive element 1 can be, for example, in a sheet form, or in the form of a photosensitive element roll wound around a core in a roll shape. In the photosensitive element roll, the photosensitive element 1 is preferably wound so that the support 2 is on the outside. The core is formed of, for example, polyethylene, polypropylene, polystyrene, polyvinyl chloride, acrylonitrile-butadiene-styrene copolymer, etc. From the viewpoint of protecting the end face, an end face partition can be provided on the end face of the photosensitive element roll, and from the viewpoint of edge fusion resistance, a moisture-proof end face partition can be provided. The photosensitive element 1 can be packaged, for example, with a black sheet having low moisture permeability.

[0098] The photosensitive element 1 can be applied to form a resist pattern, and is particularly suitable for the manufacturing method of a printed wiring board described later.

[0099] [Method for forming resist pattern]

[0100] The method for forming a resist pattern according to this embodiment includes a step of forming a photosensitive layer on a substrate having a surface roughness of 200 nm or less using the above photosensitive resin composition or the above photosensitive element (photosensitive layer forming step), a step of irradiating at least a part (specified part) of the above photosensitive layer with actinic light to form a photocured part (exposure step), and a step of removing at least a part of the above uncured part from the above substrate (development step), and may include other steps as needed. The resist pattern is also referred to as a photocured product pattern of the photosensitive resin composition, and is also referred to as a relief pattern. The method for forming a resist pattern is also referred to as a method for manufacturing a substrate with a resist pattern attached.

[0101] (Photosensitive layer forming step)

[0102] As a method for forming a photosensitive layer on a substrate, for example, it may be coating and drying the above photosensitive resin composition or heating the photosensitive layer of the photosensitive element after removing the protective layer and pressing it against the above substrate at the same time. In the case of using a photosensitive element, a laminate composed of a substrate, a photosensitive layer, and a support and laminated in this order can be obtained. There is no particular limitation on the lead frame as the above substrate, but generally, a circuit forming substrate having an insulating layer and a conductor layer formed on the insulating layer or a chip pad (die pad) such as an alloy substrate (lead frame substrate) can be used.

[0103] Regarding the surface roughness (Ra) of the substrate, from the viewpoint of suppressing halation caused by the unevenness of the substrate and improving resolution, it may be 200 nm or less, 180 nm or less, or 160 nm or less, and from the viewpoint of improving the adhesion of the resist pattern, it may be 10 nm or more, 30 nm or more, or 40 nm or more. From the viewpoint of maintaining the balance between resolution and adhesion, Ra may be 10 to 200 nm, 30 to 180 nm, or 40 to 160 nm.

[0104] In the case of using a photosensitive element, from the viewpoints of adhesion and followability, the photosensitive layer forming step is preferably performed under reduced pressure. Heating of the photosensitive layer and / or the substrate during pressing can be performed at a temperature of 70 to 130 °C. Pressing can be performed under a pressure of about 0.1 to 1.0 MPa (1 to 10 kgf / cm 2 about), but these conditions can be appropriately selected as needed. In addition, if the photosensitive layer is heated to 70 to 130 °C, it is not necessary to preheat the substrate in advance, but in order to further improve adhesion and followability, preheating of the substrate can also be performed.

[0105] (Exposure step)

[0106] In the exposure process, by irradiating at least a part of the photosensitive layer formed on the substrate with actinic light, the irradiated part of the actinic light is photocured to form a latent image. At this time, when a support is present on the photosensitive layer, if the support is transmissive to the actinic light, the actinic light can be irradiated through the support. However, when the support is light-shielding, the actinic light is irradiated on the photosensitive layer after removing the support.

[0107] As an exposure method, a method of irradiating actinic light in an image shape via a negative or positive mask pattern called an illustration (mask exposure method) can be cited. Also, a method of irradiating actinic light in an image shape by a projection exposure method can be adopted. Also, a method of irradiating actinic light in an image shape by a direct drawing exposure method such as an LDI (Laser Direct Imaging) exposure method or a DLP (Digital Light Processing) exposure method can be adopted.

[0108] As a light source for actinic light, a known light source can be used. For example, a gas laser such as a carbon arc lamp, a mercury vapor arc lamp, a high-pressure mercury lamp, a xenon lamp, an argon laser, a solid laser such as a YAG laser, ultraviolet rays such as a semiconductor laser, and a light source that effectively emits visible light can also be used.

[0109] (Development process)

[0110] In the development process, by removing at least a part of the uncured portion (other than the photocured portion) of the photosensitive layer from the substrate, a resist pattern is formed on the substrate. When a support is present on the photosensitive layer, after removing the support, the area other than the above photocured portion (also called the unexposed portion) is removed (developed). The development methods are wet development and dry development, and wet development can be widely used.

[0111] In the case of wet development, a developer corresponding to the photosensitive resin composition is used, and development is performed by a known development method. As the development method, methods such as an immersion method, a spin coating immersion method, a spray method, brushing, scrubbing, and rocking immersion can be cited. From the viewpoint of improving resolution, a high-pressure spray method can also be used as the development method. Two or more of these methods can also be combined for development.

[0112] The composition of the developer can be appropriately selected according to the composition of the above photosensitive resin composition. As the developer, for example, an alkaline aqueous solution and an organic solvent developer can be cited.

[0113] From the viewpoints of safety, stability, and good operability, an alkaline aqueous solution can also be used as the developer. As the base of the alkaline aqueous solution, alkali hydroxides such as lithium, sodium, or potassium hydroxide; carbonate bases such as lithium, sodium, potassium, or ammonium carbonate or bicarbonate; alkali metal phosphates such as potassium phosphate and sodium phosphate; alkali metal pyrrolidonate salts such as sodium pyrrolidonate and potassium pyrrolidonate; borax, sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1,3-propanediol, 1,3-diaminopropan-2-ol, morpholine, etc. can be used.

[0114] As the alkaline aqueous solution for development, a diluted solution of 0.1 to 5% by mass of sodium carbonate, a diluted solution of 0.1 to 5% by mass of potassium carbonate, a diluted solution of 0.1 to 5% by mass of sodium hydroxide, a diluted solution of 0.1 to 5% by mass of sodium tetraborate, etc. can be used. The pH of the alkaline aqueous solution can be set in the range of 9 to 11, and its temperature can be adjusted according to the alkali developability of the photosensitive layer. A small amount of an organic solvent for promoting surfactants, defoamers, and development can also be mixed in the alkaline aqueous solution, for example.

[0115] As the organic solvent used in the alkaline aqueous solution, for example, acetone, ethyl acetate, alkoxyethanol having an alkoxy group with 1 to 4 carbon atoms, ethanol, isopropyl alcohol, butanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether can be cited.

[0116] As the organic solvent used in the organic solvent developer, for example, 1,1,1-trichloroethane, N-methyl-2-pyrrolidone, N,N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, and γ-butyrolactone can be cited. To prevent fire, water is added to these organic solvents in an amount in the range of 1 to 20% by mass to prepare the organic solvent developer.

[0117] In the method for forming a resist pattern of the present embodiment, it may include: after removing the uncured portion in the developing step, heating at about 60 to 250 °C or exposing at about 0.2 to 10 J / cm 2 or so as required, thereby further curing the resist pattern step.

[0118] [Method for manufacturing a printed circuit board]

[0119] The method for manufacturing a printed circuit board of the present embodiment may include the following steps: etching or plating the substrate having a resist pattern formed by the above method for forming a resist pattern to form a conductor pattern, and other steps such as a resist pattern removing step may also be included as required.

[0120] In the plating process, the resist pattern formed on the substrate is used as a mask, and plating is performed on the conductor layer provided on the substrate. After the plating process, the resist can also be removed by removing the resist pattern described later, and further, the conductor layer coated with the resist is etched to form a conductor pattern. As a method of the plating process, electrolytic plating can be used, electroless plating can be used, or electroless plating can be used.

[0121] In the etching process, the resist pattern formed on the substrate is used as a mask, and the conductor layer provided on the substrate is etched and removed to form a conductor pattern. The method of the etching process can be appropriately selected according to the conductor layer to be removed. As an etchant, for example, a copper chloride solution, an iron chloride solution, an alkaline etchant, and a hydrogen peroxide-based etchant can be cited.

[0122] After the etching process or the plating process, the resist pattern on the substrate can also be removed. The removal of the resist pattern can be performed, for example, by peeling with an aqueous solution having a stronger alkalinity than the alkaline aqueous solution used in the above-described developing step. As the strongly alkaline aqueous solution, for example, a 1 to 10 mass% sodium hydroxide aqueous solution, a 1 to 10 mass% potassium hydroxide aqueous solution, etc. can be used.

[0123] In the case where the resist pattern is removed after the plating process is performed, the conductor layer coated with the resist is further etched by the etching process to form a conductor pattern, whereby a desired printed wiring board can be manufactured. The method of the etching process at this time can be appropriately selected according to the conductor layer to be removed. For example, the above-described etchant can be applied.

[0124] The method for manufacturing a printed wiring board according to the present embodiment can be applied not only to a single-layer printed wiring board but also to the manufacturing of a multilayer printed wiring board, and can also be applied to the manufacturing of a printed wiring board having small-diameter through holes, etc.

[0125] Examples

[0126] Hereinafter, the present invention will be specifically described further by way of examples, but the present invention is not limited to these examples.

[0127] ((A) Adhesive polymer)

[0128] Solutions of the adhesive polymers (A-1) to (A-5) shown in Table 1 were prepared according to the following steps.

[0129] (A-1)

[0130] 96.1 g of acrylic acid (AA) and 339.9 g of styrene (ST) (mass ratio of AA / ST = 22.0 / 78.0) as polymerizable monomers, 4.6 g of tert-butyl peroxy-2-ethylhexanoate (manufactured by NOF CORPORATION., trade name “PERBUTYL (registered trademark) O”) as a thermal free radical polymerization initiator, and 128.6 g of propylene glycol monomethyl ether as a solvent were mixed to prepare a mixture (x). 4.4 g of PERBUTYL O was dissolved in 37.4 g of propylene glycol monomethyl ether to prepare a solution (a).

[0131] 46.2 g of propylene glycol monomethyl ether and 174.8 g of toluene were added to a flask equipped with a stirring device, a dropping funnel, a capacitor, a thermometer, and a gas inlet tube. The gas was replaced under a nitrogen atmosphere and stirred, and the temperature was raised to 98 °C. Then, the mixture (x) was added dropwise to the flask over 2 hours. After the dropping was completed, the mixture was stirred at 98 °C for 2 hours, then the solution (a) was added, and stirring was continued for 3 hours. Then, while continuing to stir, the temperature of the solution in the flask was raised to 105 °C over 20 minutes, and then stirred at 105 °C for 2 hours. Then, 93.8 g of propylene glycol monomethyl ether and 74.2 g of toluene were added, stirred, and cooled to room temperature to obtain a solution of the adhesive polymer (A-1).

[0132] (A-2)

[0133] A solution of the adhesive polymer (A-2) was obtained under the same conditions as (A-1), except that the polymerizable monomers in the mixture (x) were changed to 99.8 g of acrylic acid (AA) and 336.3 g of styrene (ST) (mass ratio of AA / ST = 22.9 / 77.1).

[0134] (A-3)

[0135] A solution of the adhesive polymer (A-3) was obtained under the same conditions as (A-1), except that the polymerizable monomers in the mixture (x) were changed to 99.6 g of acrylic acid (AA), 306.2 g of styrene (ST), and 29.4 g of dicyclopentanyl methacrylate (TCDMA) (mass ratio of AA / ST / TCDMA = 22.9 / 70.3 / 6.8), and the amount of PERBUTYLO was changed to 5.5 g.

[0136] (A-4)

[0137] A solution of the adhesive polymer (A-4) was obtained under the same conditions as (A-3), except that the amount of PERBUTYL O in the mixture (x) was changed to 11.5 g.

[0138] (A-5)

[0139] Except that the polymerizable monomers of the mixture (x) were changed to 117.1 g of methyl methacrylate (MMA), 283.0 g of styrene (ST), and 29.0 g of dicyclopentanyl methacrylate (TCDMA) (mass ratio of MAA / ST / TCDMA = 27.3 / 66.0 / 6.7), and the amount of PERBUTYL O was changed to 11.6 g, a solution of the adhesive polymer (A-5) was obtained under the same conditions as (A-1).

[0140] (Weight-average molecular weight)

[0141] As a sample for Mw measurement, the adhesive polymer solution was dissolved in tetrahydrofuran (THF) to prepare a 0.2 mass% THF solution. The measurement was carried out by gel permeation chromatography (GPC) method, and the Mw was derived by conversion using the calibration curve of standard polystyrene. The conditions of GPC are shown below.

[0142] Measuring device: Shodex (registered trademark) GPC-101 (manufactured by Showa Denko K.K.)

[0143] Detector: Differential refractometer Shodex RI-71S (manufactured by Showa Denko K.K.)

[0144] Column: Shodex LF-804 + LF-804 (manufactured by Showa Denko K.K.)

[0145] Column temperature: 40 °C

[0146] Eluent: Tetrahydrofuran (THF)

[0147] Flow rate: 1 mL / min

[0148] (Acid value)

[0149] According to JIS K6901:2008 5.3.2, the acid value of the adhesive polymer was measured by neutralization titration method.

[0150] [Table 1]

[0151]

[0152] [Photosensitive resin composition]

[0153] For the solid content of the adhesive polymer solution being 57 mass parts, the photosensitive resin compositions of the examples were prepared by mixing the components in the amounts (mass parts) shown in Table 2, and the photosensitive resin compositions of the comparative examples were prepared by mixing the components in the amounts (mass parts) shown in Table 3. The details of each component shown in Table 2 and Table 3 are as follows.

[0154] ((B) Photopolymerizable compound)

[0155] B-1: 2,2-bis(4-(methacryloxypentaethoxy)phenyl)propane (manufactured by Showa Denko Materials Co., Ltd., trade name “FA-321M”, EO average number: 10)

[0156] B-2: Ethoxylated bisphenol A dimethacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: “BP-2EM”, EO average number: 2.6)

[0157] B-3: PO·EO·PO modified dimethacrylate (manufactured by Showa Denko Materials co., Ltd.), trade name “FA-024M”, EO average number: 6, PO average number: 12)

[0158] ((C) Photoinitiator)

[0159] C-1: 2,2’-bis(2-chlorophenyl)-4,4’,5,5’-tetraphenyl benzimidazole (manufactured by Hampford)

[0160] ((D) Sensitizer)

[0161] D-1: 1-phenyl-3-(4-methoxystyryl)-5-(4-methoxyphenyl)pyrazoline (manufactured by Nippon Chemical Industry Co., Ltd., trade name “PZ-501D”)

[0162] D-2: 4,4’-bis(diethylamino)benzophenone (manufactured by HODOGAYA CHEMICAL CO., LTD.)

[0163] ((E) Polymerization inhibitor)

[0164] E-1: 4-tert-butylcatechol (manufactured by DIC Corporation)

[0165] E-2: 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl (manufactured by ADEKA CORPORATION, trade name “LA-7RD”)

[0166] (Other components)

[0167] Sealing agent: A mixture of carboxybenzotriazole, 5-amino-1H-tetrazole, and methoxypropanol (manufactured by SANWAKASEI CORP, trade name "SF-808H")

[0168] Photochromogenic agent: Colorless crystal violet (manufactured by YAMADA CHEMICAL CO., LTD.)

[0169] Dye: Malachite green (manufactured by OSAKA ORGANIC CHEMICAL INDUSTRY LTD.)

[0170] [Photosensitive element]

[0171] As a support, a polyethylene terephthalate film with a thickness of 16 μm (manufactured by TORAY INDUSTRIES, INC., trade name "FS-31") was prepared. After coating the photosensitive resin composition on the support, it was dried in a hot air convection dryer at 90 °C for 10 minutes to form a photosensitive layer with a dried thickness of 25 μm. Then, a polyethylene film (manufactured by TAMAPOLY CO., LTD., trade name "NF-15A") was laminated as a protective layer on the photosensitive layer to obtain a photosensitive element having a support, a photosensitive layer, and a protective layer laminated in sequence.

[0172] (Absorbance and transmittance)

[0173] The photosensitive element was laminated (stacked) on the surface of a glass slide (manufactured by Matsunami Glass Ind., Ltd., white glass slide cut No. 1S1126). The protective layer was peeled off and the photosensitive layer of the photosensitive element was brought into contact with the surface of the glass slide, and lamination was performed using a hot roll at 110 °C under a crimping pressure of 0.4 MPa and a roll speed of 1.0 m / min. After laminating the photosensitive layer on the glass slide, the support was peeled off. The absorbance and transmittance of the photosensitive layer were measured using a U-3310 type spectrophotometer (manufactured by Hitachi High-Tech Corporation) under the measurement conditions of a wavelength range: 330 to 700 nm, a scanning speed: 300 nm / min, a scanning interval: 0.50 nm, and a slit width: 2 nm. Baseline measurement was performed using an untreated glass slide as a reference and a sample. The glass slide laminated with the photosensitive layer was set on the sample side holder, and the untreated glass slide was set on the reference side holder for measurement. Based on the obtained absorption spectrum, the absorbance and transmittance at the exposure wavelength (365 nm) were recorded as the absorbance and transmittance of the photosensitive layer. Also, by dividing the absorbance of the photosensitive layer by the thickness of the photosensitive layer, the absorbance per 1 μm thickness was calculated.

[0174] [Laminate]

[0175] The substrate (Ra: 150 nm) with electroless copper plating applied on the umami - flavored laminated film (registered trademark) ABF (AJINOMOTOFINE - TECHNO CO., INC., trade name "GL - 102") was heated to 80°C, and the photosensitive element was laminated on the copper surface of the substrate. The protective layer was peeled off and the photosensitive layer of the photosensitive element was brought into contact with the copper surface of the copper substrate. Lamination was carried out using a hot roll at 110°C, a crimping pressure of 0.4 MPa, and a roll speed of 1.0 m / min. Thus, a laminate having a substrate, a photosensitive layer, and a support laminated in sequence was obtained. The obtained laminate was used as a test piece for the tests shown below.

[0176] (Minimum development time)

[0177] The support was peeled off from the test piece to expose the photosensitive layer, and a 1% by mass aqueous sodium carbonate solution at 30°C was sprayed. The time until the photosensitive layer was completely removed was measured and taken as the minimum development time.

[0178] (Resolution and adhesion)

[0179] On the support of the test piece, a chromium glass (Glasschromium) type exposure tool (Phototool) was used as a negative for resolution and adhesion evaluation (resolution negative: a negative having a wiring pattern with a line width / space width of 3x / x (x: 1 - 10, unit: μm), adhesion negative: a negative having a wiring pattern with a line width / space width of x / 3x (x: 1 - 18, unit: μm)), and a projection exposure apparatus (manufactured by USHIO INC., trade name "UX - 2240 - SM - XJ01") using an ultra - high - pressure mercury lamp (365 nm) as a light source was used to expose the photosensitive layer with a specified amount of energy. After exposure, the support was peeled off to expose the photosensitive layer, and a 1% by mass aqueous sodium carbonate solution at 30°C was sprayed for a time twice the minimum development time to remove the unexposed portion (development process).

[0180] After the development process, the resolution and adhesion were evaluated by the value of the minimum line width / space width in the resist pattern where the space portion (unexposed portion) was completely removed and the line portion was formed without distortion, meandering, and deficiency (exposed portion). At this time, as the resolution and adhesion, the value of the line width / space width evaluated by taking the exposure amount with a resist line width of 10.0 μm for the line width / space width of the adhesion negative pattern of 10 μm / 10 μm as the above - mentioned specified amount of energy was recorded. The smaller this value, the better the resolution and adhesion.

[0181] (Peeling time)

[0182] On the support of the test piece, a chromium glass type exposure tool (exposure tool with a planar pattern of 50 mm × 40 mm) was used as a negative film for peel test evaluation, and a projection exposure apparatus (manufactured by USHIO INC., trade name "UX-2240-SM-XJ01") using an ultra-high pressure mercury lamp (365 nm) as a light source was used to expose the photosensitive layer with the above-specified amount of energy. After exposure, the support was peeled off to expose the photosensitive layer, and a 1% by mass aqueous sodium carbonate solution at 30 °C was sprayed for a time twice the minimum development time to remove the unexposed portion.

[0183] After the development treatment, it was immersed in an amine-based stripping solution heated to 50 °C (15 vol% R-100S + 8 vol% aqueous R-101 solution, manufactured by MITSUBISHI GAS CHEMICAL COMPANY, INC.). The time until the photosensitive layer was completely removed was measured and used as the peel time.

[0184] [Table 2]

[0185]

[0186] [Table 3]

[0187]

[0188] Symbol Explanation

[0189] 1 - Photosensitive element, 2 - Support, 3 - Photosensitive layer, 4 - Protective layer.

Claims

1. A photosensitive resin composition containing a binder polymer, a photopolymerizable compound, a photopolymerization initiator, and a sensitizer, wherein, the binder polymer has a structural unit derived from acrylic acid and a structural unit derived from styrene or a styrene derivative, the absorbance of the photosensitive resin composition per 1 μm thickness with respect to light of wavelength 365 nm is 0.0030 to 0.0120.

2. The photosensitive resin composition according to claim 1, wherein, the sensitizer contains a pyrazoline compound or a dialkylaminobenzophenone compound.

3. The photosensitive resin composition according to claim 1, wherein, the weight average molecular weight of the binder polymer is 10,000 to 60,000.

4. The photosensitive resin composition according to claim 1, wherein, the acid value of the binder polymer is 140 to 200 mgKOH / g.

5. The photosensitive resin composition according to claim 1, wherein, based on the total mass of the structural units derived from the polymerizable monomers constituting the binder polymer, the content of the structural unit derived from styrene or a styrene derivative is 50 to 85% by mass.

6. 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 5.

7. A method for forming a resist pattern, comprising: a step of forming a photosensitive layer on a substrate having a surface roughness of 200 nm or less using the photosensitive resin composition according to any one of claims 1 to 5; a step of irradiating at least a part of the photosensitive layer with actinic rays to form a photocured portion; and a step of removing the uncured portion of the photosensitive layer from the substrate to form a resist pattern.

8. A method for forming a resist pattern, comprising: a step of forming a photosensitive layer on a substrate having a surface roughness of 200 nm or less using the photosensitive element according to claim 6; a step of irradiating at least a part of the photosensitive layer with actinic rays to form a photocured portion; and a step of removing the uncured portion of the photosensitive layer from the substrate to form a resist pattern.

9. A method for manufacturing a printed circuit board, comprising a step of forming a conductor pattern by performing an etching treatment or a plating treatment on a substrate having a resist pattern formed by the method for forming a resist pattern according to claim 7.

10. The method for manufacturing a printed circuit board according to claim 9, further comprising a step of removing the resist pattern after the etching treatment or the plating treatment.

11. A method for manufacturing a printed circuit board, comprising a step of forming a conductor pattern by performing an etching treatment or a plating treatment on a substrate having a resist pattern formed by the method for forming a resist pattern according to claim 8.

12. The method for manufacturing a printed circuit board according to claim 11, further comprising a step of removing the resist pattern after the etching treatment or the plating treatment.

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