JP2018159841A - Photosensitive resin composition, photosensitive element, method for forming resist pattern, and method for manufacturing printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin composition excellent in sensitivity, resolution, adhesion. and peeling characteristics.SOLUTION: The alkali-developable photosensitive resin composition contains a component (A): a binder polymer, a component (B): a photopolymerizable compound having an ethylenically unsaturated bond, and a component (C): a photopolymerization initiator. The component (B) contains a bisphenol F-based acrylate compound. The component (C) contains a hexaarylbiimidazole derivative or an acridine compound.SELECTED DRAWING: None

Description

  The present invention relates to a photosensitive resin composition, a photosensitive element using the same, a method for forming a resist pattern, and a method for producing a printed wiring board.

  In the field of manufacturing printed wiring boards, as a resist material used for etching treatment, plating treatment, etc., a photosensitive resin composition or a layer formed using a photosensitive resin composition (hereinafter referred to as “photosensitive layer”). ) On a support and a photosensitive element (photosensitive film) having a structure in which a protective film is disposed on a photosensitive layer is widely used.

  Conventionally, a printed wiring board is manufactured by the following procedure, for example, using the photosensitive film. That is, first, the photosensitive layer of the photosensitive film is laminated on a circuit forming substrate such as a copper-clad laminate. At this time, the surface (hereinafter referred to as the “upper surface” of the photosensitive layer) opposite to the surface (hereinafter referred to as the “lower surface” of the photosensitive layer) of the photosensitive layer is the circuit of the circuit forming substrate. It should be in close contact with the surface on which is formed. Therefore, when the protective film is disposed on the upper surface of the photosensitive layer, the laminating operation is performed while peeling off the protective film. Lamination is performed by thermocompression bonding the photosensitive layer to an underlying circuit forming substrate (atmospheric pressure laminating method).

  Next, the photosensitive layer is pattern-exposed through a mask film or the like to form a photocured portion. At this time, the support is peeled off at any timing before or after exposure. Thereafter, the unexposed portion (region other than the photocured portion) of the photosensitive layer is dissolved or dispersed and removed with a developer. Next, an etching process or a plating process is performed to form a conductor pattern, and finally the photocured portion is peeled and removed.

  Here, the etching treatment is a method of removing the cured resist after etching away the metal surface of the circuit forming substrate not covered with the cured resist formed after development. On the other hand, the plating treatment is performed by plating the metal surface of the circuit forming substrate that is not covered with the hardened resist formed after development, such as copper and solder, and then removing the hardened resist and covering with the resist. This is a method of etching a metal surface (Semi Additive Method (SAP method)).

  In recent years, as the exposure method, there has been proposed a direct drawing exposure method called DLP (Digital Light Processing) and LDI (Laser Direct Imaging) which directly draws digital data of a pattern on a photosensitive layer. This direct drawing exposure method has better alignment accuracy than an exposure method through a photomask, and a high-definition pattern can be obtained, so that it is being introduced for the production of a high-density package substrate.

  In addition, as the printed wiring board is increased in density, the fine wiring is advanced, and the contact area between the circuit forming substrate and the photosensitive layer as the resist material is reduced. Therefore, the photosensitive layer is required to have excellent mechanical strength, chemical resistance and flexibility in the etching or plating process, as well as excellent adhesion with the circuit forming substrate and excellent resolution in pattern formation. Has been. For example, a material capable of forming a resist pattern having a line width and a space width of 10 μm or less is required.

  On the other hand, in order to improve production efficiency, shortening and shortening of each process are required. For example, an improvement in resist sensitivity and a reduction in stripping time are required at the same time as a request for resolution and the like.

  In the exposure process, in the direct drawing exposure method described above, a monochromatic light such as a laser is used as a light source, and light is irradiated while scanning the substrate. Therefore, the exposure time is longer than the exposure method using a conventional photomask. Tend to require. Therefore, it is necessary to further improve the sensitivity of the photosensitive resin composition as compared with the conventional case.

  If the resist peeling property is poor, there is a problem that the peeling time becomes long and the production efficiency of the peeling process is lowered. Moreover, in a high-density board | substrate, there exists a problem which a peeling residue arises between plating lines in the peeling process after thin wire plating, and a production yield falls.

  In relation to the above, various photosensitive resin compositions have been studied in order to form a resist pattern having an L / S (line width / space width) of 10/10 (unit: μm) or less. For example, Patent Document 1 discloses a photosensitive resin composition using a specific sensitizing dye as a photosensitive resin composition having good sensitivity that can be applied to a direct drawing exposure method. Further, for example, Patent Document 2 similarly discloses a photosensitive resin composition excellent in sensitivity and resolution by using a specific sensitizing dye. Furthermore, recently, Patent Document 3 discloses a photosensitive resin composition excellent in sensitivity and resolution by using a binder polymer obtained by polymerizing a specific copolymer component.

JP 2007-279381 A JP 2009-003177 A JP 2014-134815 A

  When using the photosensitive resin composition described in Patent Documents 1 to 3, a fine resist pattern can be formed for resolution, but the peeling characteristics are not sufficiently considered, There was room for improvement in terms of shortening of the peeling time and fragmentation of the peeled pieces.

  As described above, the conventional photosensitive resin composition is required to be further improved particularly in terms of resolution and adhesion. On the other hand, in order to improve productivity, further enhancement of sensitivity and improvement of peeling characteristics are required.

  Therefore, the present invention provides a photosensitive resin composition excellent in sensitivity, resolution, adhesion, and peeling properties, a photosensitive element using the same, a method for forming a resist pattern, and a method for producing a printed wiring board. Is an issue.

  As a result of intensive studies to solve the above problems, the present inventors have found that (A) component: a binder polymer, (B) component: a photopolymerizable compound having an ethylenically unsaturated bond, and (C) component. A photopolymerization initiator, wherein the component (B) contains a bisphenol F-based acrylate compound, and the component (C) contains a hexaarylbiimidazole derivative or an acridine compound. It has been found that the composition can achieve excellent peeling characteristics while having excellent sensitivity, resolution and adhesion, and can achieve both the photosensitive characteristics (sensitivity, resolution and adhesion) and the peeling characteristics.

［式中、ｎは０〜１０の整数を示す。］
［３］上記（Ａ）成分が、（メタ）アクリル酸に由来する構造単位と、（メタ）アクリル酸エステルに由来する構造単位と、スチレン又はスチレン誘導体に由来する構造単位とを有し、ベンゼン環の含有量が３０質量％以上であるバインダーポリマーを含有する、上記［１］又は［２］に記載の感光性樹脂組成物。
［４］上記（Ｂ）成分が、ビスフェノールＡ系（メタ）アクリレート化合物をさらに含む、上記［１］〜［３］のいずれかに記載の感光性樹脂組成物。
［５］支持体と、該支持体上に上記［１］〜［４］のいずれかに記載の感光性樹脂組成物を用いて形成された感光層と、を備える感光性エレメント。
［６］基板上に、上記［１］〜［４］のいずれかに記載の感光性樹脂組成物又は上記［５］に記載の感光性エレメントを用いて、感光層を形成する感光層形成工程と、上記感光層の所定部分に活性光線を照射して光硬化部を形成する露光工程と、上記感光層の上記光硬化部以外の領域を上記基板上から除去する現像工程と、を有するレジストパターンの形成方法。
［７］上記［６］に記載のレジストパターンの形成方法によりレジストパターンが形成された基板を、エッチング処理又はめっき処理して導体パターンを形成する工程を有する、プリント配線板の製造方法。 That is, the present invention provides the following inventions.
[1] component (A): a binder polymer, (B) component: a photopolymerizable compound having an ethylenically unsaturated bond, and (C) component: a photopolymerization initiator, wherein the component (B) is An alkali developing type photosensitive resin composition containing a bisphenol F-based acrylate compound, wherein the component (C) contains a hexaarylbiimidazole derivative or an acridine compound.
[2] The photosensitive resin composition according to [1], wherein the bisphenol F-based acrylate compound is a compound represented by the following general formula (1).

[Wherein n represents an integer of 0 to 10. ]
[3] The component (A) has a structural unit derived from (meth) acrylic acid, a structural unit derived from (meth) acrylic acid ester, and a structural unit derived from styrene or a styrene derivative, and The photosensitive resin composition as described in [1] or [2] above, which contains a binder polymer having a ring content of 30% by mass or more.
[4] The photosensitive resin composition according to any one of [1] to [3], wherein the component (B) further contains a bisphenol A-based (meth) acrylate compound.
[5] A photosensitive element comprising a support and a photosensitive layer formed using the photosensitive resin composition according to any one of [1] to [4] on the support.
[6] A photosensitive layer forming step of forming a photosensitive layer on the substrate using the photosensitive resin composition according to any one of [1] to [4] or the photosensitive element according to [5]. And an exposure step of irradiating a predetermined portion of the photosensitive layer with actinic rays to form a photocured portion, and a developing step of removing a region other than the photocured portion of the photosensitive layer from the substrate. Pattern formation method.
[7] A method for manufacturing a printed wiring board, including a step of forming a conductor pattern by etching or plating a substrate on which a resist pattern is formed by the method for forming a resist pattern according to [6].

  ADVANTAGE OF THE INVENTION According to this invention, the formation method of the photosensitive resin composition excellent in a sensitivity, resolution, adhesiveness, and peeling characteristics, a photosensitive element, a resist pattern, and the manufacturing method of a printed wiring board can be provided. .

Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof.
In this specification, the term “process” is not limited to an independent process, and is included in the term if the intended action of the process is achieved even when it cannot be clearly distinguished from other processes. .
Moreover, the numerical value range shown using "to" in this specification shows the range which includes the numerical value described before and behind "to" as a minimum value and a maximum value, respectively.
Further, when referring to the amount of each component in the composition in the present specification, when there are a plurality of substances corresponding to each component in the composition, the plurality of the components present in the composition unless otherwise specified. It means the total amount of substance.
In the present specification, (meth) acrylic acid means acrylic acid or methacrylic acid, (meth) acrylate means acrylate or a corresponding methacrylate, and (meth) acryloyl group means acryloyl group or methacryloyl group. Means.

<Photosensitive resin composition>
The photosensitive resin composition of the present embodiment comprises (A) component: binder polymer, (B) component: photopolymerizable compound having an ethylenically unsaturated bond, and (C) component: photopolymerization initiator. In addition, the component (B) contains a bisphenol F-based acrylate compound, and the component (C) contains a hexaarylbiimidazole derivative or an acridine compound. The photosensitive resin composition of the present embodiment can be suitably used as an alkali development type photosensitive resin composition. Hereinafter, each component used by the photosensitive resin composition of this embodiment is demonstrated in detail.

((A) component: binder polymer)
Component (A): The binder polymer is not particularly limited as long as it has alkali developability, but preferably a structural unit derived from (meth) acrylic acid and a structure derived from (meth) acrylic acid ester. It contains units and structural units derived from styrene or styrene derivatives.

  The binder polymer preferably contains 30% by mass or more of benzene rings in the structure. Moreover, it is more preferable from the point of resolution that a binder polymer contains 40 mass% or more of benzene rings in a structure. The content of the benzene ring in the structure of the binder polymer can be obtained as a theoretical value from, for example, the charging ratio of the copolymerization component of the polymer at the time of synthesis. The content of the benzene ring in each copolymer component can be calculated from the atomic weight.

  The binder polymer preferably contains 30% by mass or more of a structural unit derived from styrene or a styrene derivative.

  The acid value of the binder polymer is preferably 50 to 250 mgKOH / g, and more preferably 70 to 200 mgKOH / g or more from the viewpoint of achieving both developability and peeling properties.

The acid value of the binder polymer can be measured as follows. That is, first, 1 g of the binder polymer that is the object of acid value measurement is precisely weighed. 30 g of acetone is added to the precisely weighed binder polymer and dissolved uniformly. Next, an appropriate amount of phenolphthalein as an indicator is added to the solution, and titration is performed using a 0.1N potassium hydroxide (KOH) aqueous solution. The acid value is determined by calculating the number of mg of KOH required to neutralize the acetone solution of the binder polymer to be measured. When a solution obtained by mixing a binder polymer with a synthetic solvent, a diluting solvent, or the like is an object to be measured, the acid value is calculated by the following formula.
Acid value = 0.1 × Vf × 56.1 / (Wp × I / 100)
In the formula, Vf represents the titration amount (mL) of the aqueous KOH solution, Wp represents the mass (g) of the solution containing the measured binder polymer, and I represents the ratio of the nonvolatile content in the solution containing the measured binder polymer. (Mass%) is shown. In addition, when blending the binder polymer in a state mixed with volatile components such as a synthetic solvent and a diluting solvent, the mixture is preliminarily heated for 1 to 4 hours at a temperature higher than the boiling point of the volatile components by 1 to 4 hours before being volatile. The acid value can also be measured after removing the component.

  Specific examples of components of (meth) acrylic acid, (meth) acrylic acid ester, styrene, and / or styrene derivatives include styrene, vinyltoluene, α-methylstyrene, p-methylstyrene, p- Polymerizable styrene derivatives such as ethyl styrene, acrylic acid, methacrylic acid, (meth) acrylic acid alkyl ester, (meth) acrylic acid benzyl ester, (meth) acrylic acid benzyl ester derivative, (meth) acrylic acid cycloalkyl ester, (Meth) acrylic acid furfuryl ester, (meth) acrylic acid tetrahydrofurfuryl ester, (meth) acrylic acid isobornyl ester, (meth) acrylic acid adamantyl ester, (meth) acrylic acid dicyclopentanyl ester, (meta ) Dimethylaminoethyl acrylate Steal, (meth) acrylic acid diethylaminoethyl ester, (meth) acrylic acid glycidyl ester, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, β -Maleic monoesters such as furyl (meth) acrylic acid, β-styryl (meth) acrylic acid, maleic acid, maleic anhydride, monomethyl maleate, monoethyl maleate, monoisopropyl maleate, fumaric acid, cinnamic acid , Α-cyanocinnamic acid, itaconic acid, crotonic acid, propiolic acid and the like.

  Examples of the alkyl group constituting the (meth) acrylic acid alkyl ester include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, Examples include dodecyl group and structural isomers thereof. From the viewpoint of further improving the peeling characteristics, the alkyl group is preferably one having 1 to 4 carbon atoms.

  Specific examples of the (meth) acrylic acid alkyl ester include (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid propyl ester, (meth) acrylic acid butyl ester, (meth) acrylic acid. Pentyl ester, (meth) acrylic acid hexyl ester, (meth) acrylic acid heptyl ester, (meth) acrylic acid octyl ester, (meth) acrylic acid 2-ethylhexyl ester, (meth) acrylic acid nonyl ester, (meth) acrylic acid Examples include decyl ester, (meth) acrylic acid undecyl ester, and (meth) acrylic acid dodecyl ester. These may be used alone or in any combination of two or more.

  The weight average molecular weight (Mw) of the binder polymer is, for example, 10,000 to 100,000, preferably 20,000 to 100,000, more preferably 20,000 to 80,000, and further preferably 25,000 to 60,000. When the weight average molecular weight is 100,000 or less, the resolution and developability tend to be improved, and when the weight average molecular weight is 10,000 or more, the coating property tends to be improved. The weight average molecular weight of the binder polymer is measured by gel permeation chromatography (GPC) (converted with a calibration curve using standard polystyrene).

  The binder polymer of the component (A) may further have a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 30 carbon atoms as a structural unit. By introducing an alkyl chain, the trade-off between flexibility and peelability can be eliminated. 1-10 are preferable and, as for the number of carbon number of an alkyl chain, 2-6 are more preferable.

  In the photosensitive resin composition of the present embodiment, as the binder polymer, one kind of binder polymer may be used alone, or two or more kinds of binder polymers may be used in any combination. As a binder polymer in the case of using two or more types in combination, for example, two or more types of binder polymers comprising different copolymer components (including different monomer units as copolymer components), two or more types of different weight average molecular weights Examples of the binder polymer include two or more binder polymers having different degrees of dispersion. In addition, a polymer having a multimode molecular weight distribution described in JP-A No. 11-327137 can also be used.

  The content of the (A) binder polymer in the photosensitive resin composition of the present embodiment is preferably 20 to 90% by mass, and preferably 30 to 80% by mass based on the total solid content of the photosensitive resin composition. It is more preferable, and it is still more preferable that it is 40-65 mass%. There exists a tendency for the moldability of a film to be excellent in the content rate of a binder polymer being 20 mass% or more. Moreover, there exists a tendency which is excellent in a sensitivity and the resolution in it being 90 mass% or less.

((B) component: photopolymerizable compound)
Then, (B) a photopolymerizable compound is demonstrated. In the present embodiment, the photopolymerizable compound contains a bisphenol F-based acrylate compound. By including the bisphenol F-based acrylate compound as the photopolymerizable compound in the photosensitive resin composition, it is possible to greatly improve the peeling characteristics while maintaining excellent adhesion and resolution. Such an effect is considered to be based on the flexibility and hydrophilicity of the bisphenol F structure and the content of the benzene ring. The bisphenol F-based acrylate compound is preferably a compound represented by the following general formula (1).

  In formula (1), n shows the integer of 0-10. When n indicating the number of ethylene oxides in the formula is 10 or less, the ratio of the benzene rings in the compound is increased, and the resolution tends to be improved. Therefore, n is preferably a number from 0 to 10. From the viewpoints of resolution, developability, and availability, n representing the number of ethylene oxide is more preferably 1-6.

  As a bisphenol F-based acrylate compound, specifically, bisphenol F (EO) 4 diacrylate is M290 (manufactured by MIWON, product name), bisphenol F (EO) 6 diacrylate is BPF6DA (manufactured by MIWON, sample) As a name), bisphenol F (EO) 10 diacrylate is commercially available as BPF10DA (manufactured by MIWON, sample name).

  It is preferable that the photopolymerizable compound further contains at least one bisphenol A-based (meth) acrylate compound. By including at least one bisphenol A (meth) acrylate compound, it becomes easy to balance various characteristics.

  Specific examples of bisphenol A-based (meth) acrylate compounds include 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxypoly). Propoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypolybutoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane, etc. Is mentioned. Among these, 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane is preferable from the viewpoint of further improving the resolution and peeling properties.

  Of these, 2,2-bis (4-((meth) acryloxydipropoxy) phenyl) propane is commercially available as BPE-200 (manufactured by Shin-Nakamura Chemical Co., Ltd., product name). 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane as BPE-500 (made by Shin-Nakamura Chemical Co., Ltd., product name) or FA-321M (product name made by Hitachi Chemical Co., Ltd.) It is commercially available.

  These bisphenol A-based (meth) acrylate compounds are used singly or in combination of two or more.

  The content of the bisphenol F-based acrylate compound in the photopolymerizable compound is preferably 5 to 100% by mass, and 10 to 80% by mass based on the total mass of the (B) photopolymerizable compound. Is more preferable, and it is more preferable that it is 15-60 mass%. When the content is within the above range, the resolution of the resist is improved and the peelability is improved.

  The content of the photopolymerizable compound in the photosensitive resin composition is preferably 3 to 70% by mass, more preferably 10 to 60% by mass based on the total solid content of the photosensitive resin composition. More preferably, it is 25-55 mass%. There exists a tendency for a sensitivity and a resolution to be excellent in the content rate of a photopolymerizable compound being 3 mass% or more. Moreover, there exists a tendency which is excellent in the moldability of a film as it is 70 mass% or less.

  Other (B) photopolymerizable compounds other than bisphenol F-based acrylate compounds and bisphenol A-based (meth) acrylate compounds include poly (poly) oxyethylene chains and (poly) oxypropylene chains in the molecule. It further contains at least one kind of alkylene glycol di (meth) acrylate, and further contains polyalkylene glycol di (meth) acrylate having both (poly) oxyethylene chain and (poly) oxypropylene chain in the molecule. However, since the flexibility of hardened | cured material (cured film) improves, it is preferable.

  Examples of the polyalkylene glycol di (meth) acrylate include FA-023M (product name) manufactured by Hitachi Chemical Co., Ltd., FA-024M (product name manufactured by Hitachi Chemical Co., Ltd.), NK ester HEMA-9P (Shin Nakamura Chemical Co., Ltd.). Sample name). These can be used alone or in combination of two or more.

  Other (B) photopolymerizable compounds include nonylphenoxypolyethyleneoxyacrylate, phthalic acid compounds, (meth) acrylic acid polyol esters, (meth) acrylic acid alkyl esters, and the like. Among these, from the viewpoint of improving the resolution, adhesion, resist shape, and release characteristics after curing in a balanced manner, the photosensitive resin composition may include at least one selected from nonylphenoxypolyethyleneoxyacrylate and phthalic acid compounds. . However, since the refractive index of these compounds is relatively low, a smaller content is preferable.

  Examples of the nonylphenoxypolyethyleneoxyacrylate include nonylphenoxytriethyleneoxyacrylate, nonylphenoxytetraethyleneoxyacrylate, nonylphenoxypentaethyleneoxyacrylate, nonylphenoxyhexaethyleneoxyacrylate, nonylphenoxyheptaethyleneoxyacrylate, nonylphenoxyoctaethylene Examples include oxyacrylate, nonylphenoxynonaethyleneoxyacrylate, nonylphenoxydecaethyleneoxyacrylate, and nonylphenoxyundecaethyleneoxyacrylate.

  Examples of phthalic acid compounds include γ-chloro-β-hydroxypropyl-β ′-(meth) acryloyloxyethyl-o-phthalate, β-hydroxyethyl-β ′-(meth) acryloyloxyethyl-o. -Phthalate and [beta] -hydroxypropyl- [beta] '-(meth) acryloyloxyethyl-o-phthalate, in particular [gamma] -chloro- [beta] -hydroxypropyl- [beta]-(meth) acryloyloxyethyl-o- Phthalate is preferred. γ-Chloro-β-hydroxypropyl-β′-methacryloyloxyethyl-o-phthalate is commercially available as FA-MECH (manufactured by Hitachi Chemical Co., Ltd., product name).

  Furthermore, as the (meth) acrylic acid polyol ester, for example, trimethylolpropane polyethoxytri (meth) acrylate, trimethylolpropane polypropoxytri (meth) acrylate, trimethylolpropane polybutoxytri (meth) acrylate, trimethylolpropane poly Ethoxy polypropoxy tri (meth) acrylate, trimethylol ethane polyethoxy tri (meth) acrylate, trimethylol ethane polypropoxy tri (meth) acrylate, trimethylol ethane polybutoxy tri (meth) acrylate, trimethylol ethane polyethoxy polypropoxy tri (Meth) acrylate, pentaerythritol polyethoxytri (meth) acrylate, pentaerythritol polypropoxytri (meta Acrylate, pentaerythritol polybutoxytri (meth) acrylate, pentaerythritol polyethoxypolypropoxytri (meth) acrylate, glyceryl polyethoxytri (meth) acrylate, glyceryl polypropoxytri (meth) acrylate, glyceryl polybutoxytri (meth) acrylate And glyceryl polyethoxypolypropoxy tri (meth) acrylate.

  The said other photopolymerizable compound is used individually or in combination of 2 or more types.

((C) component: photopolymerization initiator)
Next, the (C) photopolymerization initiator used in this embodiment will be described. (C) As a photoinitiator which is a component, the hexaarylbiimidazole derivative or the acridine compound which has one or more acridinyl groups is contained. In addition, the photosensitive resin composition may contain both the hexaaryl biimidazole derivative and the acridine compound. When the photosensitive resin composition contains a hexaarylbiimidazole derivative or an acridine compound as a photopolymerization initiator, it is possible to balance sensitivity and resolution.

  Examples of hexaarylbiimidazole derivatives include 2- (o-chlorophenyl) -4,5-diphenylbiimidazole, 2,2 ′, 5-tris- (o-chlorophenyl) -4- (3,4-dimethoxyphenyl). ) -4 ', 5'-diphenylbiimidazole, 2,4-bis- (o-chlorophenyl) -5- (3,4-dimethoxyphenyl) -diphenylbiimidazole, 2,4,5-tris- (o- Chlorophenyl) -diphenylbiimidazole, 2- (o-chlorophenyl) -bis-4,5- (3,4-dimethoxyphenyl) -biimidazole, 2,2′-bis- (2-fluorophenyl) -4,4 ', 5,5'-tetrakis- (3-methoxyphenyl) -biimidazole, 2,2'-bis- (2,3-difluoromethylphenyl) -4 4 ′, 5,5′-tetrakis- (3-methoxyphenyl) -biimidazole, 2,2′-bis- (2,4-difluorophenyl) -4,4 ′, 5,5′-tetrakis- (3 -Methoxyphenyl) -biimidazole, 2,2'-bis- (2,5-difluorophenyl) -4,4 ', 5,5'-tetrakis- (3-methoxyphenyl) -biimidazole and the like. Among these, 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer is preferable from the viewpoint of sensitivity and resolution. These are used alone or in combination of two or more.

  Examples of the acridine compound include 9-phenylacridine, 9- (p-methylphenyl) acridine, 9- (m-methylphenyl) acridine, 9- (p-chlorophenyl) acridine, 9- (m-chlorophenyl) acridine, 9-aminoacridine, 9-dimethylaminoacridine, 9-diethylaminoacridine, 9-pentylaminoacridine, 1,2-bis (9-acridinyl) ethane, 1,4-bis (9-acridinyl) butane, 1,6- Bis (9-acridinyl) hexane, 1,8-bis (9-acridinyl) octane, 1,10-bis (9-acridinyl) decane, 1,12-bis (9-acridinyl) dodecane, 1,14-bis ( 9-Acridinyl) tetradecane, 1,16-bis (9-acridinyl) hexadecane 1,18-bis (9-acridinyl) octadecane, bis (9-acridinyl) alkanes such as 1,20-bis (9-acridinyl) eicosane, 1,3-bis (9-acridinyl) -2-oxapropane, , 3-bis (9-acridinyl) -2-thiapropane, 1,5-bis (9-acridinyl) -3-thiapentane and the like. Among these, 9-phenylacridine is preferable from the viewpoint of sensitivity and resolution. These are used alone or in combination of two or more.

  The photosensitive resin composition of this embodiment may further contain other photopolymerization initiators other than the hexaarylbiimidazole derivative and the acridine compound. Other photopolymerization initiators include, for example, benzophenones such as benzophenone and 4,4′-bis (diethylamino) benzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, Aromatic ketones such as 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propanone-1, quinones such as alkylanthraquinone, benzoin ether compounds such as benzoin alkyl ether, benzoin, alkylbenzoin and the like Benzoin compounds, benzyl derivatives such as benzyldimethyl ketal, N-phenylglycine, N-phenylglycine derivatives, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenyl Fosuf Acylphosphine oxide photopolymerization initiators such as oxide, 1,2-octanedione, 1- [4- (phenylthio) phenyl-, 2- (O-benzoyloxime)], ethanone, 1- [9-ethyl And oxime ester compounds such as -6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxime). These can be used by mixing with a hexaarylbiimidazole derivative or an acridine compound. Other photopolymerization initiators are used alone or in combination of two or more.

  (C) The content of the photopolymerization initiator is preferably 0.1 to 10% by mass, more preferably 1 to 5% by mass, based on the total solid content of the photosensitive resin composition. More preferably, it is 2-4.5 mass%. When the content is within the above range, it tends to be easy to make both the photosensitivity and the resolution sufficient as compared with the case where the content is outside the above range.

(Sensitizer)
The photosensitive resin composition preferably further contains a sensitizer. Thereby, the photosensitivity of the photosensitive resin composition is further improved. Examples of the sensitizer include, for example, dialkylaminobenzophenones, pyrazolines, anthracene, coumarins, xanthones, oxazoles, benzoxazoles, thiazoles, benzothiazoles, triazoles, stilbenes, triazines, thiophenes , Naphthalimides, and triarylamines. These are used individually by 1 type or in combination of 2 or more types. In particular, when the photosensitive layer is exposed using an actinic ray of 390 to 420 nm, the sensitizer is a group consisting of pyrazolines, anthracenes, coumarins and triarylamines from the viewpoint of sensitivity and adhesion. It is preferable to include at least one selected from the group consisting of pyrazolines, anthracenes, and triarylamines, and it is more preferable to include at least one selected from the group consisting of triarylamines.

  When the photosensitive resin composition contains a sensitizer, the content is preferably 0.01 to 10% by mass based on the total solid content of the photosensitive resin composition, and 0.05 to 5% by mass. More preferably, it is more preferable to set it as 0.1-3 mass%. When the content of the sensitizer is 0.01% by mass or more, sensitivity and resolution are further improved. Moreover, it is suppressed that a resist shape turns into an inverted trapezoid because it is 10 mass% or less, and adhesiveness improves.

(Amine compounds)
The photosensitive resin composition preferably further contains an amine compound. Thereby, the sensitivity of the photosensitive resin composition is further improved. Examples of the amine compound include bis [4- (dimethylamino) phenyl] methane, bis [4- (diethylamino) phenyl] methane, and leucocrystal violet. These are used individually by 1 type or in combination of 2 or more types.

  When the said photosensitive resin composition contains an amine compound, it is preferable that the content shall be 0.01-10 mass% on the basis of the solid content whole quantity of the photosensitive resin composition, and 0.05-5 mass %, More preferably 0.1 to 2% by mass. Sensitivity improves more because content of the said amine compound is 0.01 mass% or more. Moreover, it is suppressed that an excess amine compound precipitates as a foreign material after film formation because it is 10 mass% or less.

(Other ingredients)
The said photosensitive resin composition can contain another component as needed in addition to the said component. Other components include, for example, a photopolymerizable compound (oxetane compound, etc.) having at least one cationically polymerizable cyclic ether group in the molecule, a cationic polymerization initiator, a dye such as malachite green, tribromophenylsulfone, photochromic Agent, thermal coloring inhibitor, plasticizer such as p-toluenesulfonamide, pigment, filler, antifoaming agent, flame retardant, stabilizer, adhesion promoter, leveling agent, peeling accelerator, antioxidant, fragrance, Examples thereof include an imaging agent and a thermal crosslinking agent. These are used individually by 1 type or in combination of 2 or more types. Moreover, when a photosensitive resin composition contains these other components, it is preferable that the content shall be about 0.01-20 mass%, respectively on the basis of the solid content whole quantity of the photosensitive resin composition.

  The photosensitive resin composition can contain at least one organic solvent. As the organic solvent, a commonly used organic solvent is not particularly limited and can be used. Specific examples include methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N, N-dimethylformamide, propylene glycol monomethyl ether, and mixed solvents thereof. The photosensitive resin composition is prepared by, for example, dissolving the above (A) binder polymer, (B) photopolymerizable compound, and (C) photopolymerization initiator in the above organic solvent, and having a solid content of 30 to 60% by mass. It can be used as a solution having a degree (hereinafter referred to as “coating liquid”). In addition, solid content means the remaining component remove | excluding the volatile component from the said solution (photosensitive resin composition). That is, solid content refers to components other than the solvent that does not volatilize in the drying step, and includes liquid, syrupy, and waxy forms at room temperature around 25 ° C.

<Photosensitive element>
The photosensitive element of this embodiment includes a support and a photosensitive layer formed on the support using the photosensitive resin composition. When using the photosensitive element of this embodiment, after exposing a photosensitive layer on a board | substrate in general, you may expose, without peeling a support body (support film). The photosensitive element may further include a protective film on the surface opposite to the support of the photosensitive layer.

(Support)
As the support, a polymer film having heat resistance and solvent resistance such as polyester such as polyethylene terephthalate, polypropylene, and polyethylene can be used. However, in terms of versatility, a polyethylene terephthalate (PET) film is used. desirable.

In the present embodiment, the support adjusts the particles having a diameter of 5 μm or more contained in the support to 5 particles / mm ² or less to make the haze 0.01 to 1.0% and at the same time contains fine particles. It may be a multilayer support film provided with a resin layer. Thereby, the slipperiness of the support surface is improved, and the suppression of light scattering during exposure can be achieved at a higher level in a balanced manner. Here, a particle having a diameter of 5 μm or more means a diameter of 5 μm or more when observed using a polarizing microscope (however, if the observed particle shape is not circular, it means the diameter of the circumscribed circle of that shape) Means particles that are present on the surface of the support. The average particle size of the fine particles contained in the resin layer is 5 μm or less, preferably 1 μm or less, particularly preferably 0.1 μm or less, and the lower limit is not particularly limited, but is preferably 0.001 μm or more. The average particle diameter of the fine particles can be measured with a scanning electron microscope.

  As a commercially available general industrial film that can be used as such a multilayer support film, for example, “QS-48” (manufactured by Toray Industries, Inc.) is a biaxially oriented PET film having a three-layer structure in which the outermost layer contains fine particles. , Product name), “HTF-01” (manufactured by Teijin DuPont Films, Inc., product name), biaxially oriented PET film “A-1517” (Toyobo Co., Ltd.) having a layer containing fine particles on one side Company name, product name) and the like.

  The thickness of the support is preferably 1 to 100 μm, more preferably 5 to 50 μm, and further preferably 5 to 30 μm. It can suppress that a support body is torn when peeling a support body because the thickness of a support body is 1 micrometer or more. Moreover, when it is 100 micrometers or less, when exposing through a support body, it can suppress that the resolution falls.

(Protective film)
The photosensitive element may further include a protective film as necessary. As the protective film, it is preferable to use a film in which the adhesive force between the photosensitive layer and the protective film is smaller than the adhesive force between the photosensitive layer and the support, and a low fisheye film is used. It is preferable to use it. Specific examples include inert polyolefin films such as polyethylene and polypropylene. From the viewpoint of peelability from the photosensitive layer, a polyethylene film is preferred. Although the thickness of a protective film changes with uses, it is preferable that it is about 1-100 micrometers.

<Photosensitive element manufacturing method>
The photosensitive element can be manufactured as follows, for example. That is, the photosensitive element is obtained by dissolving (A) a binder polymer, (B) a photopolymerizable compound, and (C) a photopolymerization initiator in an organic solvent, and a coating solution having a solid content of about 30 to 60% by mass. The coating solution is coated on a support to form a coating layer, and the coating layer is dried to form a photosensitive layer. .

  Application of the coating solution onto the support can be performed by known methods such as a roll coater, comma coater, gravure coater, air knife coater, die coater, and bar coater.

  The drying of the coating layer is not particularly limited as long as at least a part of the organic solvent can be removed from the coating layer. Drying is preferably performed, for example, at 70 to 150 ° C. for about 5 to 30 minutes. After drying, the amount of the remaining organic solvent in the photosensitive layer is preferably 2% by mass or less from the viewpoint of preventing the diffusion of the organic solvent in the subsequent step.

  The thickness of the photosensitive layer in the photosensitive element can be appropriately selected depending on the use, but it is preferably 1 to 100 μm, more preferably 1 to 50 μm, and more preferably 5 to 40 μm after drying. More preferably. Industrial coating becomes easy and productivity improves because the thickness of a photosensitive layer is 1 micrometer or more. Moreover, adhesiveness and resolution improve by being 100 micrometers or less.

  The transmittance of the photosensitive layer with respect to ultraviolet rays is preferably 5 to 75%, more preferably 10 to 65%, and further preferably 15 to 55% with respect to ultraviolet rays having a wavelength of 365 nm. Adhesiveness improves more because this transmittance | permeability is 5% or more. Further, when the transmittance is 75% or less, the resolution is further improved. The transmittance can be measured with a UV spectrometer. Examples of the UV spectrometer include a 228A type W beam spectrophotometer manufactured by Hitachi, Ltd.

  The form of the photosensitive element is not particularly limited. For example, it may be in the form of a sheet, or may be in a state of being wound up in a roll shape around a core.

  When winding the photosensitive element in a roll shape, it is preferable to wind the photosensitive element so that the support is on the outside. Examples of the core material include plastics such as polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, and ABS resin (acrylonitrile-butadiene-styrene copolymer). From the viewpoint of end face protection, it is preferable to install an end face separator on the end face of the roll-shaped photosensitive element roll thus obtained, and it is preferable to install a moisture-proof end face separator from the standpoint of edge fusion resistance. Moreover, as a packaging method, it is preferable to wrap and package in a black sheet with low moisture permeability.

  The photosensitive element can be suitably used for, for example, a resist pattern forming method described later. Especially, it is suitable for the application to the manufacturing method which forms a circuit by plating processing.

<Method for forming resist pattern>
The resist pattern forming method of this embodiment includes (i) a photosensitive layer forming step of forming a photosensitive layer which is a coating film of the photosensitive resin composition on a substrate, and (ii) at least part of the photosensitive layer. An exposure step of irradiating actinic rays to form a photocured portion; and (iii) removing an uncured portion of the photosensitive layer from the substrate to form a resist pattern made of a cured product derived from the photosensitive layer. A development step, and includes other steps as necessary.

(I) Photosensitive layer formation process In the photosensitive layer formation process, the photosensitive layer which is a coating film of the said photosensitive resin composition is formed on a board | substrate. Although it does not restrict | limit especially as said board | substrate, Usually, die pads (base material for lead frames), such as a circuit formation board | substrate provided with the insulating layer and the conductor layer formed on the insulating layer, or an alloy base material are used.

  As a method for forming a photosensitive layer on a substrate, for example, the photosensitive resin composition may be applied and dried, or after removing the protective film from the photosensitive element, You may carry out by crimping | bonding to the said board | substrate, heating a photosensitive layer. Thereby, a laminate comprising the substrate, the photosensitive layer and the support, and these are sequentially laminated is obtained.

This photosensitive layer forming step is preferably performed under reduced pressure from the viewpoint of adhesion and followability. The photosensitive layer or the substrate is preferably heated at a temperature of 70 to 130 ° C. during the pressure bonding. The pressure bonding is preferably performed at a pressure of about 0.1 to 1.0 MPa (about 1 to 10 kgf / cm ² ), but these conditions are appropriately selected as necessary. If the photosensitive layer is heated to 70 to 130 ° C., it is not necessary to pre-heat the substrate in advance, but the substrate can be pre-heated in order to further improve the adhesion and followability.

(Ii) Exposure Step In the exposure step, at least a part of the photosensitive layer formed on the substrate is irradiated with actinic rays, so that the portion irradiated with actinic rays is photocured to form a latent image. . At this time, when a support is present on the photosensitive layer, the support can be irradiated with actinic rays through the support if the support is transparent to actinic rays. Irradiates the photosensitive layer with actinic rays after removing the support.

  Examples of the exposure method include a method of irradiating an actinic ray in an image form through a negative or positive mask pattern called an artwork (mask exposure method). Alternatively, a method of irradiating actinic rays in an image form by a direct drawing exposure method such as an LDI (Laser Direct Imaging) exposure method or a DLP (Digital Light Processing) exposure method may be employed.

  As the actinic ray light source, a known light source can be used. For example, a carbon arc lamp, a mercury vapor arc lamp, a high pressure mercury lamp, a xenon lamp, a gas laser such as an argon laser, a solid laser such as a YAG laser, a semiconductor laser, etc. Those that effectively emit ultraviolet light and visible light are used.

(Iii) Development Step In the development step, a resist pattern made of a cured product obtained by photocuring the photosensitive layer is formed on the substrate by removing the uncured portion of the photosensitive layer from the substrate.

  When the support is present on the photosensitive layer, the support is removed, and then the unexposed portion other than the exposed portion (photocured portion) is removed (developed). Development methods include wet development and dry development, but wet development is widely used.

  In the case of wet development, development is performed by a known development method using a developer corresponding to the photosensitive resin composition. Examples of the developing method include a method using a dipping method, a paddle method, a spray method, brushing, slapping, scrubbing, rocking immersion, and the like. From the viewpoint of improving resolution, the high pressure spray method is most suitable. You may develop by combining these 2 or more types of methods.

  The configuration of the developer is appropriately selected according to the configuration of the photosensitive resin composition. An alkaline aqueous solution is used as the developer.

  The alkaline aqueous solution is safe and stable when used as a developer, and has good operability. Examples of the base of the alkaline aqueous solution include alkali hydroxides such as lithium, sodium, or potassium hydroxide; alkali carbonates such as lithium, sodium, potassium, or ammonium carbonate or bicarbonate; potassium phosphate, sodium phosphate, and the like. Alkali metal phosphates; alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate are used.

  As alkaline aqueous solution, 0.1-5 mass% dilute solution of sodium carbonate, 0.1-5 mass% dilute solution of potassium carbonate, 0.1-5 mass% dilute solution of sodium hydroxide, 0.1-5 A dilute solution of mass% sodium tetraborate is preferred. The pH of the alkaline aqueous solution is preferably in the range of 9 to 11, and the temperature is adjusted according to the alkali developability of the photosensitive layer. In the alkaline aqueous solution, a surfactant, an antifoaming agent, a small amount of an organic solvent for promoting development, and the like may be mixed.

In this embodiment, after removing an unexposed portion in the development step, the resist pattern is further cured by heating at about 60 to 250 ° C. or exposure at about 0.2 to 10 J / cm ² as necessary. May be.

<Method for manufacturing printed wiring board>
The method for manufacturing a printed wiring board according to this embodiment includes a step of forming a conductor pattern by etching or plating a substrate (circuit forming substrate) on which a resist pattern is formed by the above-described resist pattern forming method. Depending on the above, other processes such as a resist pattern removing process may be included.

  Etching and plating of the circuit forming substrate is performed on a conductor layer or the like of the circuit forming substrate using the formed resist pattern as a mask. Etching solutions used for etching include cupric chloride solution, ferric chloride solution, alkaline etching solution, and hydrogen peroxide etching solution. It is preferable to use an iron solution.

  Moreover, as a plating method in the case of plating, for example, copper plating such as copper sulfate plating and copper pyrophosphate plating, solder plating such as high throw solder plating, Watt bath (nickel sulfate-nickel chloride) plating, nickel sulfamate, etc. Nickel plating, hard gold plating, and gold plating such as soft gold plating.

  After completion of the etching or plating, the resist pattern can be peeled off with, for example, a stronger alkaline aqueous solution than the alkaline aqueous solution used for development. As this strongly alkaline aqueous solution, for example, a 1 to 10% by mass sodium hydroxide aqueous solution, a 1 to 10% by mass potassium hydroxide aqueous solution and the like are used. Examples of the peeling method include a dipping method and a spray method, and the dipping method and the spray method may be used alone or in combination. A printed wiring board is obtained as described above.

  The printed wiring board manufactured by the method for manufacturing a printed wiring board according to the present invention may be a multilayer printed wiring board or may have a small-diameter through hole.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “part” and “%” are based on mass.

<Synthesis example>
(Synthesis of binder polymer (A-1))
A polymerizable monomer (monomer) 135 g of methacrylic acid, 25 g of methyl methacrylate, 225 g of styrene and 115 g of benzyl methacrylate (mass ratio 27/5/45/23), 3.9 g of azobisisobutyronitrile Were mixed to prepare a solution a. Further, 2.0 g of azobisisobutyronitrile was mixed with a mixed liquid (mass ratio 3: 2) of 45 g of methyl cellosolve and 30 g of toluene to prepare a solution b and a solution c.

  Into a flask equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas introduction tube, 500 g of a mixed solution of 300 g of methyl cellosolve and 200 g of toluene (mass ratio 3: 2) was added, and nitrogen gas was introduced into the flask. While stirring, the mixture was stirred and heated to 80 ° C.

  The solution a was added dropwise to the mixed solution in the flask over 4 hours, and then kept at 80 ° C. for 2 hours with stirring. Next, after the solution b was dropped into the solution in the flask over 10 minutes, the solution in the flask was kept at 80 ° C. for 2 hours while stirring. Further, the solution in the flask was heated to 90 ° C. over 30 minutes, and the solution c was added dropwise over 10 minutes, and then kept at 90 ° C. for 2 hours. Next, stirring was stopped, and the mixture was cooled to room temperature (25 ° C.) to obtain a solution of a binder polymer (A-1).

  The binder polymer (A-1) had a non-volatile content (solid content) of 44.3 mass% and a weight average molecular weight of 50,000. The weight average molecular weight was measured by gel permeation chromatography (GPC) and derived by conversion using a standard polystyrene calibration curve. The GPC conditions are shown below.

<GPC conditions>
Pump: Hitachi L-6000 (manufactured by Hitachi, Ltd.)
Column: The following three total Gelpack GL-R420
Gelpack GL-R430
Gelpack GL-R440 (Hitachi Chemical Co., Ltd., product name)
Eluent: Tetrahydrofuran Measurement temperature: 40 ° C
Flow rate: 2.05 mL / min Detector: Hitachi L-3300 type RI (manufactured by Hitachi, Ltd.)

(Synthesis of binder polymer (A-2) and (A-3))
As the polymerizable monomer (monomer), except that the materials shown in Table 1 below were used in the mass ratio shown in the same table (monomer total amount 500 g), the same procedure as in obtaining the binder polymer (A-1) solution was performed. A solution of binder polymers (A-2) and (A-3) was obtained. The nonvolatile content (solid content) of the binder polymers (A-2) and (A-3) was 44.3% by mass. Moreover, about content of the benzene ring in a binder polymer, the benzene ring content of the polymerizable monomer (monomer) was calculated from atomic weight, and it calculated | required as a theoretical value from preparation ratio. The results are shown in Table 1.

<Examples 1-6 and Comparative Examples 1-5>
[Preparation of photosensitive resin composition]
(A) Binder polymer obtained by the above method, and (B) a photopolymerizable compound, (C) a photopolymerization initiator, and other components described later are blended in amounts (parts by mass) shown in Table 2 below. The photosensitive resin compositions of Examples 1 to 6 and Comparative Examples 1 to 5 were prepared respectively. In addition, the compounding quantity of (A) binder polymer shown in Table 2 is the mass (solid content) of non volatile matter.

(B) Photopolymerizable compound B-1: 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane (10 mol EO modified product) [FA-321M (manufactured by Hitachi Chemical Co., Ltd., product name)]
B-2: Bisphenol F diacrylate (4 mol EO modified product) [M290 (manufactured by MIWON, product name)]
B-3: Bisphenol F-based diacrylate (modified by 10 mol EO) [BPF10EO (manufactured by MIWON, sample name)
B-4: 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane (4 mol EO modified product) [BPE-200 (manufactured by Shin-Nakamura Chemical Co., Ltd., product name)]
B-5: Bisphenol F dimethacrylate (4 molEO modified product) [BPF4EOM (manufactured by MIWON, sample name)]
B-6: Dipentaerythritol hexaacrylate [DPHA (manufactured by Nippon Kayaku Co., Ltd., product name)]

(C) Photopolymerization initiator C-1: 2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole [B-CIM (manufactured by Hampford, product name)]
C-2: 9-phenylacridine [9PA (manufactured by Nippon Steel Chemical Co., Ltd., product name)]

(Other)
Sensitizer: 9,10 dibutoxyanthracene [DBA (manufactured by Kawasaki Kasei Kogyo Co., Ltd., product name)]
Amine compound: leuco crystal violet [LCV (manufactured by Yamada Chemical Co., Ltd., product name)]
Dye: Malachite Green [MKG (Osaka Organic Chemical Co., Ltd., product name)]
Polymerization inhibitor (serious prohibition agent): tert-butylcatechol [TBC (product name) manufactured by Wako Pure Chemical Industries, Ltd.]
Additive: N-phenylglycine [NPG (manufactured by Tokyo Chemical Industry Co., Ltd., product name)]
Additive: Tribromomethylphenyl sulfone [TPS (Changzhou Power Electronics New Materials Co., Ltd., product name)]
Additive: p-Toluenesulfonamide [PTSA (manufactured by Wako Pure Chemical Industries, Ltd., product name)]
Additive: Benzotriazole derivative [SF-808H (manufactured by Sanwa Kasei Kogyo Co., Ltd., product name)]

<Preparation of photosensitive element>
The photosensitive resin composition obtained above was uniformly coated on a 16 μm-thick polyethylene terephthalate film (product name “FB-40”, manufactured by Toray Industries, Inc.) as a support. Subsequently, it dried with a 70 degreeC and 110 degreeC hot-air convection-type dryer, and formed the photosensitive layer whose film thickness after drying is 25 micrometers. A protective film (manufactured by Tamapoly Co., Ltd., product name “NF-15”) is bonded onto this photosensitive layer, and a photosensitive element in which a polyethylene terephthalate film (support), a photosensitive layer, and a protective film are sequentially laminated I got each.

<Production of laminate>
A copper-clad laminate (substrate, manufactured by Hitachi Chemical Co., Ltd., product name “MLC-E-679”), which is a glass epoxy material in which copper foil (thickness: 35 μm) is laminated on both sides, is subjected to surface roughening treatment liquid “MEC”. Surface treatment was performed using “Hetch Bond CZ-8100” (product name, manufactured by MEC Co., Ltd.), followed by water washing, pickling and water washing, followed by drying with an air stream. The surface-treated copper clad laminate was heated to 80 ° C., and the photosensitive elements obtained in Examples 1 to 6 and Comparative Examples 1 to 5 were laminated (laminated) on the copper surface of the copper clad laminate. Lamination is performed by peeling the protective film so that the photosensitive layer of each photosensitive element is in contact with the copper surface of the copper clad laminate. Per minute. In this way, a laminate in which the copper clad laminate, the photosensitive layer, and the support were laminated in this order was obtained. The obtained laminate was used as a test piece in the following tests.

<Evaluation>
(Photosensitivity measurement test)
On the support of the test piece obtained above, a density region of 0.00 to 2.00 as a negative mask, a density step of 0.05, a tablet size of 20 mm × 187 mm, and a size of each step of 3 mm × 12 mm. A photo tool having a 41-step tablet was placed. Next, the photosensitive layer was exposed with a predetermined energy amount using a DLP exposure machine (product name “DE-1UH” manufactured by Via Mechanics Co., Ltd.) using a laser having a wavelength of 405 nm as a light source.

After the exposure, the support was peeled off. Next, a 1% by mass aqueous sodium carbonate solution at 30 ° C. was sprayed for a time twice as short as the shortest development time (the shortest time during which the unexposed portion was removed) to remove the unexposed portion (development processing). After the development processing, the energy amount (mJ / cm ² ) at which the number of steps of the step tablet of the photocured film formed on the substrate was 14.0 was determined, and the photosensitivity of the photosensitive resin composition was evaluated. Evaluation what photosensitivity of less than 30 mJ / cm ² "A", those photosensitivity of 30 mJ / cm ² or more 100 mJ / cm ² or less "B", those which photosensitivity is more than 100 mJ / cm ² " C ”. In addition, the light sensitivity shows a better result as the energy amount is lower. In the evaluation of photosensitivity, “A” is the best, followed by “B”, and “C” is inferior in photosensitivity.

(Resolution and adhesion measurement test)
For the photosensitive layer of the test piece obtained above, the drawing data having a wiring pattern with a line width / space width of n / n (n = 10 to 120 (unit: μm)) as a resolution evaluation pattern, Exposure was performed using a DLP exposure machine (product name “DE-1UH” manufactured by Via Mechanics Co., Ltd.) using a 405 nm laser as a light source. The exposure was performed with an exposure amount at which the number of remaining steps after development of the Hitachi 41-step tablet was 14.0. After the exposure, the same development processing as in the photosensitivity measurement test was performed.

  After the current processed image, the space portion (unexposed portion) is removed cleanly, and the line portion (exposed portion) is formed with the smallest line width / space width among the resist patterns formed without meandering and chipping. The resolution was evaluated. The smaller this value, the better the resolution.

  Adhesion is evaluated based on the line width of the portion where the pattern remains with the smallest line width, using a pattern having a line width: space width ratio of 1: 3 and forming a pattern in the same manner as the resolution evaluation. did. The smaller this value, the better the adhesion.

(Peeling property evaluation)
A DLP exposure machine (via via) using a laser with a wavelength of 405 nm as a light source, using phototool data for forming a 45 mm × 65 mm rectangular cured film for the evaluation of peeling characteristics on the photosensitive layer of the test piece obtained above. The product was exposed with an energy amount (mJ / cm ² ) at which the number of steps of the step tablet was 14.0 using a product name “DE-1UH” manufactured by Mechanics Co., Ltd. Subsequently, development processing was performed under the same conditions as in the photosensitivity measurement test to remove unexposed portions.

  Thereafter, 300 ml of a 3.0% NaOH aqueous solution (stripping solution) at 50 ° C. was prepared in a beaker having a capacity of 400 ml. While stirring the stripping solution at 200 revolutions / minute (rpm) using a stirring bar having a length of 30 mm, the test piece after development was immersed in the stripping solution, and the time until the cured film was separated from the substrate was measured. Furthermore, the cured film after peeling was observed and the size of the peeling piece was confirmed. It can be said that the faster the time until the cured film is separated from the substrate, the shorter the peeling time and the better the peeling characteristics. Moreover, it can be said that peeling characteristics are so favorable that the size of a peeling piece is small. The results are shown in Table 3. The peel piece size shown in Table 3 means the length of the long side of the largest peel piece, and “sheet” means that the cured film is peeled off in a sheet form without being fragmented. It can be said that the peeling characteristics are good if the peeling time is at least 60 seconds or less. In addition, it can be said that the shorter the peeling time and the smaller the peeling piece size, the better the peeling characteristics. When the peeling time exceeds 60 seconds, the peeling properties are inferior.

  As is apparent from Table 3, the photosensitive elements produced using the photosensitive resin compositions of Examples 1 to 6 have a short peeling time of 1 minute or less and are excellent in photosensitivity, resolution and adhesion. It was a thing. On the other hand, the photosensitive element produced using the photosensitive resin composition of Comparative Examples 1-5 was inferior in peeling characteristics, and the balance of both characteristics was inferior, although it was excellent in resolution and adhesiveness.

  In addition, Example 6 and Comparative Example 5 are the results when using different types of photopolymerization initiators from the other Examples and Comparative Examples, and the comparison of characteristics is performed by both. Moreover, the result with the outstanding balance was obtained with the resin composition of this invention.

  According to the present invention, a photosensitive resin composition having excellent sensitivity, resolution, adhesion, and peeling properties, a photosensitive element using the same, a method for forming a resist pattern, and a method for producing a printed wiring board Can be provided.

Claims (7)

(A) component: binder polymer,
(B) component: a photopolymerizable compound having an ethylenically unsaturated bond;
(C) component: a photopolymerization initiator,
Including
The component (B) contains a bisphenol F-based acrylate compound,
An alkali developing type photosensitive resin composition, wherein the component (C) contains a hexaarylbiimidazole derivative or an acridine compound. The photosensitive resin composition of Claim 1 whose said bisphenol F-type acrylate compound is a compound represented by following General formula (1).

[Wherein n represents an integer of 0 to 10. ]   The component (A) has a structural unit derived from (meth) acrylic acid, a structural unit derived from (meth) acrylic acid ester, and a structural unit derived from styrene or a styrene derivative, and contains a benzene ring. The photosensitive resin composition of Claim 1 or 2 containing the binder polymer whose quantity is 30 mass% or more.   The photosensitive resin composition as described in any one of Claims 1-3 in which the said (B) component further contains a bisphenol A type (meth) acrylate compound.   A photosensitive element provided with a support body and the photosensitive layer formed using the photosensitive resin composition as described in any one of Claims 1-4 on this support body. A photosensitive layer forming step of forming a photosensitive layer on the substrate using the photosensitive resin composition according to any one of claims 1 to 4 or the photosensitive element according to claim 5,
An exposure step of irradiating a predetermined portion of the photosensitive layer with actinic rays to form a photocured portion;
A developing step of removing regions other than the photocured portion of the photosensitive layer from the substrate;
A method for forming a resist pattern having   A method for manufacturing a printed wiring board, comprising: forming a conductor pattern by etching or plating a substrate on which a resist pattern is formed by the method for forming a resist pattern according to claim 6.