JP6828546B2 - Photosensitive resin composition, photosensitive element, resist pattern forming method and printed wiring board manufacturing method - Google Patents

Description

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

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

Conventionally, a printed wiring board is manufactured by using the above-mentioned photosensitive film, for example, by the following procedure. 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 opposite to the surface in contact with the support film of the photosensitive layer (hereinafter referred to as "lower surface" of the photosensitive layer) (hereinafter referred to as "upper surface" of the photosensitive layer) is the circuit of the circuit forming substrate. Make sure that it is in close contact with the surface that forms. Therefore, when the protective film is arranged on the upper surface of the photosensitive layer, the laminating work is performed while peeling off the protective film. Further, laminating is performed by heat-pressing the photosensitive layer to the underlying circuit-forming substrate (normal pressure laminating method).

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

Here, the etching process is a method of peeling off the cured resist after etching and removing the metal surface of the circuit-forming substrate that is not covered with the cured resist formed after development. On the other hand, in the plating process, the metal surface of the circuit-forming substrate that is not coated with the cured resist formed after development is plated with copper, solder, or the like, and then the cured resist is removed and coated with this resist. This is a method of etching a metal surface (semi-adaptive process (Semi Adaptive Process: SAP method)).

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

Further, as the density of the printed wiring board increases, the wiring becomes finer, and the contact area between the circuit board and the photosensitive layer, which is a resist material, becomes smaller. 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 to the circuit forming substrate and excellent resolution in pattern formation. Has been done. For example, there is a demand for a material capable of forming a resist pattern having both a line width and a space width of 10 μm or less.

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

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

If the peeling property of the resist is poor, there is a problem that the peeling time becomes long and the production efficiency of the peeling process is lowered. Further, in a high-density substrate, there is a problem that peeling residue is generated between plating lines in the peeling step after fine wire plating, and the production yield is lowered.

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 also discloses a photosensitive resin composition having excellent sensitivity and resolution by using a specific sensitizing dye. Further, recently, Patent Document 3 discloses a photosensitive resin composition having excellent sensitivity and resolution by using a binder polymer obtained by polymerizing a specific copolymerization component.

Japanese Unexamined Patent Publication No. 2007-279381 JP-A-2009-0031777 Japanese Unexamined Patent Publication No. 2014-134815

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

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

Therefore, the present invention provides a photosensitive resin composition having excellent sensitivity, resolution, adhesion and peeling characteristics, a photosensitive element using the same, a method for forming a resist pattern, and a method for manufacturing a printed wiring board. Is the subject.

As a result of diligent studies to solve the above problems, the present inventors have made a component (A): a binder polymer, a component (B): a photopolymerizable compound having an ethylenically unsaturated bond, and a component (C). : An alkali-developed photosensitive resin containing a photopolymerization initiator, the component (B) containing a bisphenol F-based acrylate compound, and the component (C) containing a hexaarylbiimidazole derivative or an aclysine compound. It has been found that the composition can realize excellent peeling characteristics while maintaining excellent sensitivity, resolution and adhesion, and can achieve both photosensitive characteristics (sensitivity, resolution and adhesion) and 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] The component (A) includes a binder polymer, a component (B): a photopolymerizable compound having an ethylenically unsaturated bond, and a component (C): a photopolymerization initiator. An alkali-developed photosensitive resin composition containing a bisphenol F-based acrylate compound and the component (C) above containing a hexaarylbiimidazole derivative or an aclysine compound.
[2] The photosensitive resin composition according to the above [1], wherein the bisphenol F-based acrylate compound is a compound represented by the following general formula (1).

[In the formula, n represents an integer from 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 is benzene. The photosensitive resin composition according to the above [1] or [2], 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 the above [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 on the support using the photosensitive resin composition according to any one of the above [1] to [4].
[6] A photosensitive layer forming step of forming a photosensitive layer on a substrate by using the photosensitive resin composition according to any one of the above [1] to [4] or the photosensitive element according to the above [5]. A resist having an exposure step of irradiating a predetermined portion of the photosensitive layer with active light to form a photocurable portion, and a developing step of removing a region other than the photocurable portion of the photosensitive layer from the substrate. How to form a pattern.
[7] A method for manufacturing a printed wiring board, comprising 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 the above [6].

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 producing a printed wiring board, which are excellent in sensitivity, resolution, adhesion, and peeling characteristics. ..

Hereinafter, the present invention will be described in detail according to its preferred embodiment.
In the present specification, the term "process" is included in this term not only as an independent process but also as long as the desired action of the process is achieved even if it cannot be clearly distinguished from other processes. ..
In addition, the numerical range indicated by using "-" in the present specification indicates a range including the numerical values before and after "-" as the minimum value and the maximum value, respectively.
Further, when the amount of each component in the composition is referred to in the present specification, when a plurality of substances corresponding to each component are present in the composition, the plurality of substances present in the composition unless otherwise specified. It means the total amount of substances.
Further, in the present specification, (meth) acrylic acid means acrylic acid or methacrylic acid, (meth) acrylate means acrylate or methacrylate corresponding thereto, and (meth) acryloyl group means acryloyl group or methacrylic acid group. Means.

<Photosensitive resin composition>
The photosensitive resin composition of the present embodiment contains (A) component: a binder polymer, (B) component: a photopolymerizable compound having an ethylenically unsaturated bond, and (C) component: a photopolymerization initiator. The component (B) contains a bisphenol F-based acrylate compound, and the component (C) contains a hexaarylbiimidazole derivative or an aclysine compound. The photosensitive resin composition of the present embodiment can be suitably used as an alkali-developed photosensitive resin composition. Hereinafter, each component used in the photosensitive resin composition of the present embodiment will be described in more detail.

(Component (A): 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 a unit and a structural unit derived from styrene or a styrene derivative.

The binder polymer preferably contains a benzene ring in an amount of 30% by mass or more in the structure. Further, it is more preferable that the binder polymer contains 40% by mass or more of a benzene ring in the structure from the viewpoint of resolvability. 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 components of the polymer at the time of synthesis. The content of the benzene ring in each copolymerization component can be calculated from the atomic weight.

The binder polymer preferably contains 30% by mass or more of structural units 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 characteristics.

The acid value of the binder polymer can be measured as follows. That is, first, 1 g of the binder polymer whose acid value is to be measured is precisely weighed. 30 g of acetone is added to the finely weighed binder polymer, and this is uniformly dissolved. Next, an appropriate amount of phenolphthalein, which is an indicator, is added to the solution, and titration is performed using a 0.1 N 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, etc. is used as a measurement target, the acid value is calculated by the following formula.
Acid value = 0.1 x Vf x 56.1 / (Wp x I / 100)
In the formula, Vf indicates the titer (mL) of the KOH aqueous solution, Wp indicates the mass (g) of the measured solution containing the binder polymer, and I indicates the ratio of the non-volatile content in the measured solution containing the binder polymer. (Mass%) is shown. When the binder polymer is mixed with volatile components such as a synthetic solvent and a diluting solvent, it is volatile by heating it in advance at a temperature 10 ° C. or higher higher than the boiling point of the volatile components for 1 to 4 hours before weighing. It is also possible to measure the acid value after removing the minutes.

Specific examples of the constituents of (meth) acrylic acid, (meth) acrylic acid ester, styrene, and / or styrene derivatives include styrene, vinyltoluene, α-methylstyrene, p-methylstyrene, and p-. Polymerizable styrene derivatives such as ethylstyrene, 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, (Meta) Acrylic Acid Flufuryl Estel, (Meta) Acrylic Acid Tetrahydrofurfuryl Estel, (Meta) Acrylic Acid Isobornyl Estel, (Meta) Acrylic Acid Adamantyl Estel, (Meta) Acrylic Acid Dicyclopentanyl Estel, (Meta) ) Acrylic acid dimethylaminoethyl ester, (meth) acrylic acid diethylaminoethyl ester, (meth) acrylic acid glycidyl ester, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl Maleic acid monoesters such as (meth) acrylate, β-frill (meth) acrylic acid, β-styryl (meth) acrylic acid, maleic acid, maleic acid anhydride, monomethyl maleate, monoethyl maleate, monoisopropyl maleate, etc. Examples thereof include fumaric acid, silicic acid, α-cyanoacrylic acid, itaconic acid, crotonic acid and propioleic acid.

Examples of alkyl groups 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 and undecyl group. Examples thereof include a dodecyl group and structural isomers thereof. From the viewpoint of further improving the peeling characteristics, the alkyl group preferably has 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, and (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 thereof include decyl ester, (meth) acrylic acid undecyl ester, and (meth) acrylic acid dodecyl ester. These can 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 even more 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 film property tends to be improved. The weight average molecular weight of the binder polymer is measured by gel permeation chromatography (GPC) (converted by 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 constituent unit. By introducing an alkyl chain, the trade-off between flexibility and peelability can be eliminated. The number of carbon atoms in the alkyl chain is preferably 1 to 10, and more preferably 2 to 6.

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. When two or more kinds of binder polymers are used in combination, for example, two or more kinds of binder polymers (including different monomer units as copolymerization components) composed of different copolymerization components, and two or more kinds of different weight average molecular weights. Binder polymers and two or more types of binder polymers with different dispersities can be mentioned. Further, a polymer having a multimode molecular weight distribution described in JP-A-11-327137 can also be used.

The content of the binder polymer (A) in the photosensitive resin composition of the present embodiment is preferably 20 to 90% by mass, preferably 30 to 80% by mass, based on the total solid content of the photosensitive resin composition. More preferably, it is more preferably 40 to 65% by mass. When the content of the binder polymer is 20% by mass or more, the formability of the film tends to be excellent. Further, when it is 90% by mass or less, the sensitivity and the resolution tend to be excellent.

(Component (B): Photopolymerizable compound)
Subsequently, (B) the photopolymerizable compound will be described. In the present embodiment, the photopolymerizable compound contains a bisphenol F-based acrylate compound. By containing the bisphenol F-based acrylate compound as the photopolymerizable compound in the photosensitive resin composition, it is possible to significantly improve the peeling characteristics while maintaining excellent adhesion and resolution. It is considered that such an effect is obtained 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 equation (1), n represents an integer from 0 to 10. When n indicating the number of ethylene oxides in the formula is 10 or less, the ratio of the benzene ring in the compound becomes high, and the resolution tends to be improved. Therefore, n is preferably a number from 0 to 10. From the viewpoint of resolution, developability, and availability, n indicating the number of ethylene oxides is more preferably 1 to 6.

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

The photopolymerizable compound preferably further contains at least one bisphenol A-based (meth) acrylate compound. By including at least one of the bisphenol A-based (meth) acrylate compounds, it becomes easy to balance various properties.

Specific examples of the bisphenol A-based (meth) acrylate compound include 2,2-bis (4-((meth) acryloxipolyethoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxypoly) phenyl) propane. Propoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxipolybutoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxipolyethoxypolypropoxy) phenyl) propane, etc. Can be mentioned. Of these, 2,2-bis (4-((meta) acryloxipolyethoxy) phenyl) propane is preferable from the viewpoint of further improving the resolution and peeling characteristics.

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

These bisphenol A-based (meth) acrylate compounds are used alone or in any 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, preferably 10 to 80% by mass, based on the total mass of (B) the photopolymerizable compound. Is more preferable, and 15 to 60% by mass is more preferable. When the content is in such a 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. It is more preferably 25 to 55% by mass. When the content of the photopolymerizable compound is 3% by mass or more, the sensitivity and resolution tend to be excellent. Further, when it is 70% by mass or less, the formability of the film tends to be excellent.

Examples of the (B) photopolymerizable compound other than the bisphenol F-based acrylate compound and the bisphenol A-based (meth) acrylate compound include poly having at least one of a (poly) oxyethylene chain and a (poly) oxypropylene chain in the molecule. Further containing at least one of alkylene glycol di (meth) acrylates, and further containing polyalkylene glycol di (meth) acrylates having both (poly) oxyethylene chains and (poly) oxypropylene chains in the molecule. However, it is preferable because the flexibility of the cured product (cured film) is improved.

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

Further, examples of the other (B) photopolymerizable compound include nonylphenoxypolyethylene oxyacrylate, a phthalic acid compound, a (meth) acrylic acid polyol ester, and a (meth) acrylic acid alkyl ester. Among them, the photosensitive resin composition may contain at least one selected from nonylphenoxypolyethyleneoxyacrylate and phthalic acid compounds from the viewpoint of improving the resolution, adhesion, resist shape and peeling characteristics after curing in a well-balanced manner. .. However, since the refractive index of these compounds is relatively low, it is preferable that the content is low.

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

Examples of the phthalic acid-based compound include γ-chloro-β-hydroxypropyl-β'-(meth) acryloyloxyethyl-o-phthalate and β-hydroxyethyl-β'-(meth) acryloyloxyethyl-o. -Futalate and β-hydroxypropyl-β'-(meth) acryloyloxyethyl-o-phthalate are mentioned, and among them, γ-chloro-β-hydroxypropyl-β'-(meth) acryloyloxyethyl-o- Phthylate is preferred. γ-Chloro-β-hydroxypropyl-β'-methacryloyloxyethyl-o-phthalate is commercially available as FA-MECH (manufactured by Hitachi Kasei Co., Ltd., product name).

Further, as the (meth) acrylic acid polyol ester, for example, trimethylolpropane polyethoxytri (meth) acrylate, trimethylolpropanepolypropoxytri (meth) acrylate, trimethylolpropanepolybutoxytri (meth) acrylate, trimethylolpropanepoly. Ethoxypolypropoxytri (meth) acrylate, trimethylolethanepolyethoxytri (meth) acrylate, trimethylolethanepolypropoxytri (meth) acrylate, trimethylolethanepolybutoxytri (meth) acrylate, trimethylolethanepolyethoxypolypropoxytri (Meta) acrylate, pentaerythritol polyethoxytri (meth) acrylate, pentaerythritol polypropoxytri (meth) acrylate, pentaerythritol polybutoxytri (meth) acrylate, pentaerythritol polyethoxypolypropoxytri (meth) acrylate, glyceryl polyethoxy Examples thereof include tri (meth) acrylate, glyceryl polypropoxytri (meth) acrylate, glyceryl polybutoxytri (meth) acrylate, and glyceryl polyethoxypolypropoxytri (meth) acrylate.

The other photopolymerizable compounds may be used alone or in combination of two or more.

(Component (C): Photopolymerization Initiator)
Next, the (C) photopolymerization initiator used in the present embodiment will be described. The photopolymerization initiator as the component (C) contains a hexaarylbiimidazole derivative or an acridine compound having one or more acridinyl groups. The photosensitive resin composition may contain both a hexaarylbiimidazole derivative and an acridine compound. When the photosensitive resin composition contains a hexaarylbiimidazole derivative or an acridine compound as a photopolymerization initiator, sensitivity and resolution can be balanced.

Examples of the hexaarylbiimidazole derivative include 2- (o-chlorophenyl) -4,5-diphenylbiimidazole, 2,2', 5-tris- (o-chlorophenyl) -4- (3,4-dimethoxyphenyl). ) -4', 5'-diphenylbimidazole, 2,4-bis- (o-chlorophenyl) -5- (3,4-dimethoxyphenyl) -diphenylbimidazole, 2,4,5-tris- (o-) Chlorophenyl) -diphenylbimidazole, 2- (o-chlorophenyl) -bis-4,5- (3,4-dimethoxyphenyl) -bimidazole, 2,2'-bis- (2-fluorophenyl) -4,4 ', 5,5'-Tetrax- (3-methoxyphenyl) -biimidazole, 2,2'-bis- (2,3-difluoromethylphenyl) -4,4', 5,5'-Tetrax- (3) -Methenylphenyl) -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'-tetrax- (3-methoxyphenyl) -biimidazole and the like. Of 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 acrydin compound include 9-phenylacrine, 9- (p-methylphenyl) acrydin, 9- (m-methylphenyl) acrydin, 9- (p-chlorophenyl) acrydin, 9- (m-chlorophenyl) acrydin, and the like. 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 ( Bis (9-acridinyl) alkanes such as 9-acrydinyl) tetradecane, 1,16-bis (9-acridinyl) hexadecane, 1,18-bis (9-acridinyl) octadecane, 1,20-bis (9-acridinyl) icosane, etc. , 1,3-bis (9-acridinyl) -2-oxapropane, 1,3-bis (9-acridinyl) -2-thiapropane, 1,5-bis (9-acridinyl) -3-thiapentane and the like. .. Of 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 the present embodiment may further contain a hexaarylbiimidazole derivative and other photopolymerization initiators other than the acridine compound. Other photopolymerization initiators include, for example, benzophenone, benzophenones such as 4,4'-bis (diethylamino) benzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2-Methyl-1- [4- (methylthio) phenyl] -2-morpholino-aromatic ketones such as propanone-1, quinones such as alkylanthraquinone, benzoin ether compounds such as benzoin alkyl ethers, benzoin, alkylbenzoin and the like Benzoyl compounds, benzyl derivatives such as benzyl dimethyl ketal, N-phenylglycine, N-phenylglycine derivatives, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenyl Acylphosphine oxide-based photopolymerization initiators such as phosphine oxide, 1,2-octanedione, 1- [4- (phenylthio) phenyl-, 2- (O-benzoyloxime)], etanone, 1- [9- Examples thereof include oxime ester compounds such as ethyl-6- (2-methylbenzoyl) -9H-carbazole-3-yl]-, 1- (O-acetyloxime). These can be used in combination with a hexaarylbiimidazole derivative or an acridine compound. Other photopolymerization initiators are used alone or in combination of two or more.

The content of the photopolymerization initiator (C) 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. It is more preferably 2 to 4.5% by mass. When this content is within the above range, it tends to be easy to make both the light sensitivity and the resolution sufficient as compared with the case where it is outside the above range.

(Sensitizer)
The photosensitive resin composition preferably further contains a sensitizer. As a result, the light sensitivity of the photosensitive resin composition becomes even better. Examples of the sensitizer include dialkylaminobenzophenones, pyrazolines, anthracenes, coumarins, xanthones, oxazoles, benzoxazoles, thiazoles, benzothiazoles, triazoles, stilbenes, triazines, and thiophenes. , Naphthalimides, triarylamines and the like. These are used alone or in combination of two or more. In particular, when the photosensitive layer is exposed with active light 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 contain at least one selected from the above, and it is more preferable to include at least one selected from the group consisting of pyrazolines, anthracenes and triarylamines.

When the photosensitive resin composition contains a sensitizer, the content thereof is preferably 0.01 to 10% by mass, preferably 0.05 to 5% by mass, based on the total solid content of the photosensitive resin composition. It is more preferably 0.1 to 3% by mass. When the content of the sensitizer is 0.01% by mass or more, the sensitivity and resolution are further improved. Further, when it is 10% by mass or less, it is possible to prevent the resist shape from becoming an inverted trapezoid and improve the adhesion.

(Amine compound)
The photosensitive resin composition preferably further contains an amine compound. As a result, the sensitivity of the photosensitive resin composition becomes even better. Examples of the amine compound include bis [4- (dimethylamino) phenyl] methane, bis [4- (diethylamino) phenyl] methane, and leuco crystal violet. These are used alone or in combination of two or more.

When the photosensitive resin composition contains an amine compound, the content thereof is preferably 0.01 to 10% by mass, preferably 0.05 to 5% by mass, based on the total solid content of the photosensitive resin composition. It is more preferably 0.1 to 2% by mass, and further preferably 0.1 to 2% by mass. When the content of the amine compound is 0.01% by mass or more, the sensitivity is further improved. Further, when it is 10% by mass or less, it is possible to suppress the precipitation of excess amine compounds as foreign substances after film formation.

(Other ingredients)
The photosensitive resin composition may contain other components in addition to the above components, if necessary. 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, tribromophenyl sulfone, and photocoloring. Agents, thermal color inhibitors, plasticizers such as p-toluenesulfonamide, pigments, fillers, antifoaming agents, flame retardants, stabilizers, adhesion imparting agents, leveling agents, peeling accelerators, antioxidants, fragrances, Examples thereof include an imaging agent and a thermal cross-linking agent. These are used alone or in combination of two or more. When the photosensitive resin composition contains these other components, the content thereof is preferably about 0.01 to 20% by mass, respectively, based on the total solid content of the photosensitive resin composition.

The photosensitive resin composition may contain at least one organic solvent. As the organic solvent, a commonly used organic solvent can be used without particular limitation. Specific examples thereof include methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N, N-dimethylformamide, propylene glycol monomethyl ether, and a mixed solvent thereof. In the photosensitive resin composition, for example, the above (A) binder polymer, (B) photopolymerizable compound, and (C) photopolymerization initiator are dissolved in the above organic solvent, and the solid content is 30 to 60% by mass. It can be used as a solution (hereinafter referred to as "coating solution"). The solid content means the remaining components obtained by removing the volatile components from the above solution (photosensitive resin composition). That is, the solid content refers to components other than the solvent that remain without volatilizing in the drying step, and includes liquid, starch syrup-like and wax-like components at room temperature around 25 ° C.

<Photosensitive element>
The photosensitive element of the present embodiment includes a support and a photosensitive layer formed on the support using the photosensitive resin composition. When the photosensitive element of the present embodiment is used, generally, after laminating the photosensitive layer on the substrate, exposure may be performed without peeling the support (support film). Further, the photosensitive element may further include a protective film on the surface of the photosensitive layer opposite to the support.

(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, but a polyethylene terephthalate (PET) film may be used from the viewpoint of versatility. 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 so that the haze is 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. As a result, the slipperiness of the surface of the support is improved, and the suppression of light scattering during exposure can be achieved in a well-balanced manner at a higher level. Here, particles having a diameter of 5 μm or more mean 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. ), Which means particles or the like existing 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 size of the fine particles can be measured by 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.), which 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 Film Co., Ltd., product name), biaxially oriented PET film "A-1517" (Toyobo Co., Ltd.) with a two-layer structure having a layer containing fine particles on one side. Company-made, product name), etc.

The thickness of the support is preferably 1 to 100 μm, more preferably 5 to 50 μm, and even more preferably 5 to 30 μm. When the thickness of the support is 1 μm or more, it is possible to prevent the support from being torn when the support is peeled off. Further, when it is 100 μm or less, it is possible to suppress a decrease in resolution when exposure is performed through a support.

(Protective film)
The photosensitive element may further include a protective film, if 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 fish eye film is used. It is preferable to use it. Specific examples thereof include an inert polyolefin film such as polyethylene and polypropylene. A polyethylene film is preferable from the viewpoint of peelability from the photosensitive layer. The thickness of the protective film varies depending on the application, but is preferably about 1 to 100 μm.

<Photosensitive element manufacturing method>
The photosensitive element can be manufactured, for example, as follows. That is, the photosensitive element is a coating liquid having a solid content of about 30 to 60% by mass by dissolving (A) a binder polymer, (B) a photopolymerizable compound, and (C) a photopolymerization initiator in an organic solvent. Can be produced by a production method including the above-mentioned preparation, coating the coating liquid on a support to form a coating layer, and drying the coating layer to form a photosensitive layer. ..

The coating liquid can be applied onto the support by, for example, a known method of a roll coater, a comma coater, a gravure coater, an air knife coater, a die coater, and a bar coater.

Further, 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 at, for example, 70 to 150 ° C. for about 5 to 30 minutes. After drying, the amount of residual organic solvent in the photosensitive layer is preferably 2% by mass or less from the viewpoint of preventing diffusion of the organic solvent in a later step.

The thickness of the photosensitive layer in the photosensitive element can be appropriately selected depending on the intended use, but the thickness after drying is preferably 1 to 100 μm, more preferably 1 to 50 μm, and 5 to 40 μm. Is even more preferable. When the thickness of the photosensitive layer is 1 μm or more, industrial coating is facilitated and productivity is improved. Further, when it is 100 μm or less, the adhesion and the resolution are improved.

The transmittance of the photosensitive layer with respect to ultraviolet rays is preferably 5 to 75%, more preferably 10 to 65%, and even more preferably 15 to 55% with respect to ultraviolet rays having a wavelength of 365 nm. When the transmittance is 5% or more, the adhesion is further improved. Further, when the transmittance is 75% or less, the resolution is further improved. The transmittance can be measured by 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 around a winding core in a roll shape.

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

The photosensitive element can be suitably used, for example, in a resist pattern forming method described later. Above all, it is suitable for application to a manufacturing method in which a circuit is formed by a plating process.

<Method of forming resist pattern>
The method for forming the resist pattern of the present embodiment includes (i) a step of forming a photosensitive layer which is a coating film of the photosensitive resin composition on a substrate, and (ii) at least a part of the photosensitive layer. An exposure step of irradiating with active light to form a photocurable portion, and (iii) removing the uncured portion of the photosensitive layer from the substrate to form a resist pattern composed of a cured product derived from the photosensitive layer. It includes a developing step and, if necessary, other steps.

(I) Photosensitive layer forming step In the photosensitive layer forming step, a photosensitive layer which is a coating film of the photosensitive resin composition is formed on a substrate. The substrate is not particularly limited, but usually a circuit-forming substrate having an insulating layer and a conductor layer formed on the insulating layer, or a die pad (lead frame substrate) such as an alloy substrate is used.

The method for forming the photosensitive layer on the substrate may be, for example, by applying and drying the photosensitive resin composition, or after removing the protective film from the photosensitive element, the photosensitive element may be formed. This may be done by pressing the photosensitive layer against the substrate while heating it. As a result, a laminate composed of a substrate, a photosensitive layer, and a support, and these are laminated in this order can be 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 the time of pressure bonding at a temperature of 70 to 130 ° C. Further, the crimping 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 preheat the substrate in advance, but the substrate can be preheated in order to further improve the adhesion and the followability.

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

Examples of the exposure method include a method of irradiating an active ray in an image shape through a negative or positive mask pattern called artwork (mask exposure method). Further, a method of irradiating an active ray in an image shape by a direct drawing exposure method such as an LDI (Laser Direct Imaging) exposure method and a DLP (Digital Light Processing) exposure method may be adopted.

As the light source of the active light, a known light source can be used, for example, a carbon arc lamp, a mercury steam arc lamp, a high-pressure mercury lamp, a xenon lamp, a gas laser such as an argon laser, a solid-state laser such as a YAG laser, a semiconductor laser, or the like. Those that effectively emit ultraviolet rays and visible light are used.

(Iii) Development Step In the developing step, the uncured portion of the photosensitive layer is removed from the substrate, so that a resist pattern made of a cured product obtained by photocuring the photosensitive layer is formed on 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). There are two types of development methods, wet development and dry development, and wet development is widely used.

In the case of wet development, development is carried out by a known development method using a developer corresponding to the photosensitive resin composition. Examples of the developing method include a dip method, a paddle method, a spray method, brushing, slapping, scraping, rocking immersion, and the like, and the high pressure spray method is the most suitable from the viewpoint of improving the resolution. Development may be performed by combining these two or more methods.

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

When used as a developing solution, the alkaline aqueous solution is safe, stable, and has good operability. Examples of the base of the alkaline aqueous solution include alkali hydroxides such as hydroxides of lithium, sodium or potassium; alkali carbonates such as carbonates or bicarbonates of lithium, sodium, potassium or ammonium; potassium phosphate, sodium phosphate and the like. Alkali metal phosphate; Alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate are used.

As the alkaline aqueous solution, a dilute solution of 0.1 to 5% by mass sodium carbonate, a dilute solution of 0.1 to 5% by mass potassium carbonate, a dilute solution of 0.1 to 5% by mass sodium hydroxide, 0.1 to 5 A dilute solution of mass% sodium tetraborate or the like is preferable. The pH of the alkaline aqueous solution is preferably in the range of 9 to 11, and the temperature is adjusted according to the alkaline developability of the photosensitive layer. A surface active agent, a defoaming agent, a small amount of an organic solvent for accelerating development, or the like may be mixed in the alkaline aqueous solution.

In the present embodiment, after removing the unexposed portion in the developing step, the resist pattern is further cured by heating at about 60 to 250 ° C. or exposing at about 0.2 to 10 J / cm ² as necessary. You may.

<Manufacturing method of printed wiring board>
The method for manufacturing a printed wiring board of the present embodiment includes a step of etching or plating a substrate on which a resist pattern is formed (a circuit-forming substrate) by the above-mentioned resist pattern forming method to form a conductor pattern, which is necessary. Depending on the situation, other steps such as a resist pattern removing step may be included.

Etching and plating of the circuit-forming substrate are performed on the conductor layer and the like of the circuit-forming substrate using the formed resist pattern as a mask. Examples of the etching solution for etching include a cupric chloride solution, a ferric chloride solution, an alkali etching solution, and a hydrogen peroxide etching solution. Among these, the second chloride solution has a good etch factor. It is preferable to use an iron solution.

In addition, as a plating method for plating, for example, copper plating such as copper sulfate plating and copper pyrophosphate plating, solder plating such as high-slow solder plating, watt bath (nickel sulfate-nickel chloride) plating, nickel sulfamate, etc. Nickel plating, hard gold plating, soft gold plating and other gold plating can be mentioned.

After the etching or plating is completed, the resist pattern can be peeled off with, for example, a stronger alkaline aqueous solution than the alkaline aqueous solution used for development. 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, or the like is used. Examples of the peeling method include a dipping method and a spraying method, and the dipping method and the spraying method may be used alone or in combination. From the above, a printed wiring board can be obtained.

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

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. Unless otherwise specified, "parts" and "%" are based on mass.

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

500 g of a mixture of 300 g of methyl cellosolve and 200 g of toluene (mass ratio 3: 2) was put into a flask equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel and a nitrogen gas introduction tube, and nitrogen gas was put into the flask. The mixture was stirred while blowing, and heated to 80 ° C. to raise the temperature.

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

The non-volatile content (solid content) of the binder polymer (A-1) was 44.3% by mass, and the weight average molecular weight was 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 conditions of GPC are shown below.

<GPC conditions>
Pump: Hitachi L-6000 (manufactured by Hitachi, Ltd.)
Column: A total of 3 of the following Gelpack GL-R420
Gelpack GL-R430
Gelpack GL-R440 (above, manufactured by Hitachi Kasei 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 polymers (A-2) and (A-3))
As the polymerizable monomer (monomer), the materials shown in Table 1 below were used in the mass ratio (total amount of monomers 500 g) shown in the same table, except that the solution of the binder polymer (A-1) was obtained in the same manner as in obtaining the solution. Solutions of binder polymers (A-2) and (A-3) were obtained. The non-volatile content (solid content) of the binder polymers (A-2) and (A-3) was 44.3% by mass. Further, regarding the content of the benzene ring in the binder polymer, the benzene ring content of the polymerizable monomer (monomer) was calculated from the atomic weight and obtained as a theoretical value from the charging ratio. The results are shown in Table 1.

<Examples 1 to 6 and Comparative Examples 1 to 5>
[Preparation of photosensitive resin composition]
The amount (parts by mass) of the (A) binder polymer obtained by the above method, (B) photopolymerizable compound described later, (C) photopolymerization initiator, and other components shown in Table 2 below. The photosensitive resin compositions of Examples 1 to 6 and Comparative Examples 1 to 5 were prepared by mixing with. The blending amount of the binder polymer (A) shown in Table 2 is the mass of the non-volatile component (solid content).

(B) Photopolymerizable Compound B-1: 2,2-Bis (4- (methacryloxypentaethoxy) phenyl) propane (10 molEO modified product) [FA-321M (manufactured by Hitachi Kasei Co., Ltd., product name)]
B-2: Bisphenol F-based diacrylate (4 molEO modified product) [M290 (manufactured by MIWON, product name)]
B-3: Bisphenol F-based diacrylate (10 molEO modified product) [BPF10EO (manufactured by MIWON, sample name)
B-4: 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane (4 molEO modified product) [BPE-200 (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., product name)]
B-5: Bisphenol F-based 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 Chemicals, Inc., product name)]
Amine-based compound: Leuco Crystal Violet [LCV (manufactured by Yamada Chemical Co., Ltd., product name)]
Dye: Malachite Green [MKG (manufactured by Osaka Organic Chemical Industry Co., Ltd., product name)]
Polymerization inhibitor (heavy inhibitor): tert-butylcatechol [TBC (manufactured by Wako Pure Chemical Industries, Ltd., product name)]
Additive: N-Phenylglycine [NPG (manufactured by Tokyo Chemical Industry Co., Ltd., product name)]
Additive: Tribromomethylphenyl sulfone [TPS (manufactured by Changshu Strong 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 applied onto each support, a polyethylene terephthalate film having a thickness of 16 μm (manufactured by Toray Industries, Inc., product name “FB-40”). Then, it was dried in a hot air convection dryer at 70 ° C. and 110 ° C. to form a photosensitive layer having a film thickness of 25 μm after drying. A protective film (manufactured by Tamapoli Co., Ltd., product name "NF-15") is attached to this photosensitive layer, and a polyethylene terephthalate film (support), a photosensitive layer, and a protective film are laminated in this order to form a photosensitive element. I got each.

<Preparation of laminate>
A copper-clad laminate (substrate, manufactured by Hitachi Kasei 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 used as a surface roughening treatment liquid "MEC". The surface was treated with "Epoxy Bond CZ-8100" (manufactured by MEC Co., Ltd., product name), washed with water, pickled and washed with water, and then dried 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 on the copper surface of the copper-clad laminate. In the lamination, while peeling off the protective film, the photosensitive layer of each photosensitive element is in contact with the copper surface of the copper-clad laminate, and a heat roll of 110 ° C. is used to obtain a pressure bonding pressure of 0.4 MPa and 1.0 m. The roll speed was / 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 test shown below.

<Evaluation>
(Light sensitivity measurement test)
On the support of the test piece obtained above, the concentration region 0.00 to 2.00, the concentration step 0.05, the tablet size 20 mm × 187 mm, and the size of each step are 3 mm × 12 mm as a negative mask. A photo tool having a 41-step step tablet was placed. Next, the photosensitive layer was exposed with a predetermined amount of energy using a DLP exposure machine (manufactured by Via Mechanics, Ltd., product name "DE-1UH") 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 sodium carbonate aqueous solution at 30 ° C. was sprayed for twice the shortest development time (the shortest time for removing the unexposed portion) to remove the unexposed portion (development treatment). After the development treatment, the amount of energy (mJ / cm ² ) at which the number of steps of the photocurable film step tablet formed on the substrate was 14.0 was determined, and the light sensitivity 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 " It was designated as "C". The lower the amount of energy, the better the light sensitivity. In the evaluation of the light sensitivity, "A" is the best, then "B" is the best, and "C" is inferior in the light sensitivity.

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

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

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

(Evaluation of peeling characteristics)
A DLP exposure machine (via) using a laser with a wavelength of 405 nm as a light source using photo tool data that forms a rectangular cured film of 45 mm × 65 mm on the photosensitive layer of the test piece obtained above for evaluation of peeling characteristics. Exposure was performed with an energy amount (mJ / cm ² ) at which the number of steps of the step tablet was 14.0 according to the product name "DE-1UH" manufactured by Mechanics, Ltd.). Next, a development process was performed under the same conditions as in the above photosensitivity measurement test to remove the unexposed portion.

Then, 300 ml of a 3.0% NaOH aqueous solution (stripping liquid) at 50 ° C. was prepared in a beaker having a capacity of 400 ml. While stirring the stripping solution at 200 rpm (rpm) using a stirrer having a length of 30 mm, the developed test piece 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 to confirm the size of the peeled piece. It can be said that the faster the time required for the cured film to separate from the substrate, the shorter the peeling time and the better the peeling characteristics. Further, it can be said that the smaller the size of the peeled piece, the better the peeling characteristic. The results are shown in Table 3. The peeling piece size shown in Table 3 means the length of the long side of the largest peeling piece, and "sheet" means that the cured film was peeled off in the form of a sheet without being fragmented. It can be said that the peeling characteristics are good if the peeling time is at least 60 seconds or less. On top of that, the shorter the peeling time and the smaller the peeling piece size, the better the peeling characteristics. If the peeling time exceeds 60 seconds, the peeling characteristics are inferior.

As is clear from Table 3, the photosensitive elements produced by using the photosensitive resin compositions of Examples 1 to 6 have a short peeling time of 1 minute or less and are excellent in light sensitivity, resolution and adhesion. It was a thing. On the other hand, the photosensitive elements produced by using the photosensitive resin compositions of Comparative Examples 1 to 5 having excellent resolution and adhesion were inferior in peeling characteristics and the balance between the two characteristics was inferior.

It should be noted that Examples 6 and 5 are the results when different types of photopolymerization initiators are used from the other Examples and Comparative Examples, and the characteristics are compared between the two. In addition, excellently balanced results were obtained with the resin composition of the present invention.

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

Claims (7)

(A) Ingredient: Binder polymer and
Component (B): A photopolymerizable compound having an ethylenically unsaturated bond,
Component (C): Photopolymerization initiator and
Including
The component (B) contains a bisphenol F-based acrylate compound and contains
An alkali-developed photosensitive resin composition containing a hexaarylbiimidazole derivative or an acridine compound as the component (C). The photosensitive resin composition according to claim 1, wherein the bisphenol F-based acrylate compound is a compound represented by the following general formula (1).

[In the formula, n represents an integer from 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 according to claim 1 or 2, which contains a binder polymer in an amount of 30% by mass or more. The photosensitive resin composition according to any one of claims 1 to 3, wherein the component (B) further contains a bisphenol A-based (meth) acrylate compound. A photosensitive element comprising a support and a photosensitive layer formed on the support using the photosensitive resin composition according to any one of claims 1 to 4. A photosensitive layer forming step of forming a photosensitive layer on a substrate by 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 active light to form a photocurable portion.
A developing step of removing a region other than the photocurable 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 a step of etching or plating a substrate on which a resist pattern is formed by the method for forming a resist pattern according to claim 6 to form a conductor pattern.