JP2018138962A - Photosensitive resin composition for laser direct writing exposure, 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 for laser direct writing exposure having excellent adhesion, resolution and acid resistance, and sufficient photosensitivity, and a photosensitive element using the same, a method for forming a resist pattern, and a method for manufacturing a printed wiring board.SOLUTION: A photosensitive resin composition for laser direct writing exposure contains (A) a binder polymer, (B) a photopolymerizable compound, (C) a photopolymerization initiator, (D) a compound having a mercapto group and (E) a compound having an anthracene skeleton as a sensitizer. A photosensitive element contains a support, and a photosensitive layer formed on the support with the photosensitive resin composition for laser direct writing exposure.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a photosensitive resin composition for direct laser exposure, a photosensitive element, 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 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”). A photosensitive element provided with a substrate on a support is widely used.

  Conventionally, a printed wiring board is manufactured by the following procedure, for example, using the photosensitive element. That is, first, the photosensitive layer of the photosensitive element is laminated on a circuit forming substrate such as a copper clad laminate. Next, the photosensitive layer is 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 region other than the photocured portion of the photosensitive layer is 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 removed.

  In recent years, from the viewpoint of further increasing the density of printed wiring boards, an LDI (laser direct imaging) method, which is a method of directly drawing a pattern produced by CAD (computer-aided design) without using a mask and using laser light, has been introduced. An applicable photosensitive resin composition is desired.

  Some light sources used in LDI include those having a dominant wavelength of around 365 nm, around 405 nm, or both. In particular, by using only a wavelength near 405 nm as a light source, deterioration of the apparatus due to laser light energy can be suppressed. Therefore, a highly sensitive photosensitive resin composition that can be applied to a direct drawing method using only a wavelength near 405 nm as a light source is desired.

  In the direct drawing method, light is irradiated while scanning the substrate, so that the exposure time is short and the light transmittance to the bottom of the resist is low.

  Patent Document 1 and Patent Document 2 describe a photosensitive resin composition for laser direct drawing exposure. However, even these methods have not reached a level that can sufficiently satisfy the problem of insufficient adhesion caused by moving the laser at high speed.

Japanese Patent Laying-Open No. 2015-197656 JP 2010-217287 A

  The direct drawing method that performs exposure by moving the laser at high speed is a conventional exposure method that uses a light source that effectively emits ultraviolet light, such as a carbon arc lamp, a mercury vapor arc lamp, an ultra-high pressure mercury lamp, a high-pressure mercury lamp, and a xenon lamp. Compared with, the amount of exposure energy per spot is small and the production efficiency is low. Therefore, in the direct drawing method, a photosensitive resin composition with higher sensitivity is required.

  Therefore, in order to improve the photosensitivity, when the amount of the photopolymerization initiator or sensitizer contained in the photosensitive resin composition is increased, the photoreaction proceeds locally at the top of the photosensitive resin composition layer, Since the curability is lowered, there arises a problem that the acid resistance is deteriorated because the resist pattern is peeled off during the acid etching.

  The present invention has been made in view of the above problems, and is a photosensitive resin composition for laser direct drawing exposure having excellent adhesion, resolution and acid resistance, and sufficient photosensitivity, and a photosensitive element using the same. An object of the present invention is to provide a resist pattern forming method and a printed wiring board manufacturing method.

  In order to achieve the above object, the present invention provides (A) a binder polymer, (B) a photopolymerizable compound, (C) a photopolymerization initiator, (D) a compound having a mercapto group, and (E) a sensitizer. The present invention relates to a photosensitive resin composition for laser direct drawing exposure, which contains a compound having an anthracene skeleton.

  In addition, the present invention relates to the above-described photosensitive resin composition for laser direct drawing exposure, wherein the compound having a mercapto group as the component (D) preferably contains a compound having a secondary thiol or a tertiary thiol.

  The present invention also relates to a photosensitive element comprising a support and a photosensitive layer formed on the support using the above-described photosensitive resin composition for laser direct drawing exposure.

  The present invention also includes (i) a step of forming a photosensitive layer on the circuit-forming substrate using the above-mentioned photosensitive resin composition for laser direct drawing exposure or the above-mentioned photosensitive element, and (ii) ) Irradiating a predetermined portion of the photosensitive layer with actinic rays to form a photocured portion; and (iii) removing at least a portion other than the photocured portion from the circuit forming substrate. And a resist pattern forming method.

Furthermore, this invention relates to the manufacturing method of a printed wiring board provided with the process of forming the conductor pattern by carrying out the etching process or the plating process to the board | substrate with which the resist pattern was formed by said resist pattern formation method.
Moreover, this invention relates to the manufacturing method of said printed wiring board further provided with the process of removing a photocuring part after the process of forming a conductor pattern.

  ADVANTAGE OF THE INVENTION According to this invention, the photosensitive resin composition for laser direct drawing exposure which is excellent in adhesiveness and the resolution, and has sufficient photosensitivity can be provided. Moreover, the photosensitive element which has the said outstanding characteristic, the formation method of a resist pattern, and the manufacturing method of a printed wiring board can be provided using this.

It is a schematic cross section which shows an example of the photosensitive element.

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. It is. Moreover, the numerical value range shown using "to" shows the range which includes the numerical value described before and behind "to" as a minimum value and a maximum value, respectively. In addition, in the numerical ranges described stepwise in the present specification, the upper limit value or lower limit value of a numerical range of a certain step may be replaced with the upper limit value or lower limit value of the numerical range of another step. Further, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples. Further, the term “layer” includes a structure formed in a part in addition to a structure formed over the entire surface when observed as a plan view. “(Meth) acrylic acid” means at least one of “acrylic acid” and “methacrylic acid” corresponding thereto. The same applies to other similar expressions such as (meth) acrylate.
The “(poly) ethyleneoxy group” means at least one of an ethyleneoxy group (hereinafter also referred to as “EO group”) or a polyethyleneoxy group in which two or more ethylene groups are connected by an ether bond. The “(poly) propyleneoxy group” means at least one of a propyleneoxy group (hereinafter also referred to as “PO group”) or a polypropyleneoxy group in which two or more propylene groups are connected by an ether bond. “EO-modified” means a compound having a (poly) ethyleneoxy group, “PO-modified” means a compound having a (poly) propyleneoxy group, and “EO · PO” “Modified” means a compound having both a (poly) ethyleneoxy group and a (poly) propyleneoxy group.

  Furthermore, 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. Means the total amount of substances.

<Photosensitive resin composition for laser direct drawing exposure>
The photosensitive resin composition for laser direct drawing exposure of this embodiment includes (A) a binder polymer, (B) a photopolymerizable compound, (C) a photopolymerization initiator, (D) a compound having a mercapto group, and (E). A compound having an anthracene skeleton is contained as a sensitizer. In the present specification, these components may be simply referred to as (A) component, (B) component, (C) component, (D) component, (E) component, and the like. Moreover, you may contain a solvent, a dye hydrogen donor, or another component as needed. Hereinafter, each component used with the photosensitive resin composition for laser direct drawing exposure of this embodiment is demonstrated in detail.

((A) binder polymer)
The (A) binder polymer according to the present embodiment (hereinafter, also referred to as “component (A)”) has a structural unit derived from (meth) acrylic acid from the viewpoint of improving resolution and adhesion, and is available. (A) The binder polymer is a structural unit derived from any one of styrene and a styrene derivative (also referred to as “specific structural unit”). You may contain 65 mass% or more on the basis of the total amount of solid content of a component. Moreover, there exists a tendency which (A) binder polymer contains a specific structural unit in the said range, and improves resolution and adhesiveness.

(A) component: binder polymer having a carboxyl group in the molecule As the component (A) that can be used in this embodiment, there is no particular limitation as long as it has a carboxyl group in the molecule and can impart film properties. Examples thereof include acrylic resins, styrene resins, epoxy resins, amide resins, amide epoxy resins, alkyd resins, phenol resins, and urethane resins. Among these, acrylic resins are preferable from the viewpoint of alkali developability. These can be used alone or in combination of two or more.

The component (A) can be produced, for example, by radical polymerization of a polymerizable monomer having a carboxyl group and another polymerizable monomer. Examples of the polymerizable monomer include styrene; polymerizable styrene derivatives such as α-methylstyrene, p-methylstyrene, and p-ethylstyrene; acrylamide; acrylonitrile; and esters of vinyl alcohol such as vinyl-n-butyl ether. ; (Meth) acrylic acid alkyl ester, (meth) acrylic acid glycidyl ester, (meth) acrylic acid, β-furyl (meth) acrylic acid, β-styryl (meth) acrylic acid, etc. Maleic acid; maleic acid monoester; fumaric acid, cinnamic acid, α-cyanocinnamic acid, itaconic acid, crotonic acid, propiolic acid.
As the polymerizable monomer having a carboxyl group, (meth) acrylic acid is preferred from the viewpoints of developability and stability. Moreover, these can be used as a homopolymer alone or in combination of two or more as a copolymer.

Examples of the (meth) acrylic acid alkyl ester include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, (meth ) Hexyl acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and structural isomers thereof. Especially, it is preferable to contain methyl (meth) acrylate and butyl (meth) acrylate in the point which is excellent in developability and the resolution.
Moreover, as a binder polymer which has a carboxyl group in a molecule | numerator, for example, the (meth) acrylic acid and the copolymer which has a (meth) acrylic acid ester containing a hydroxyl group in a structural unit, and an isocyanate group are contained (meth). What reacted (meth) acrylic acid ester containing acrylic acid ester on normal reaction conditions is mentioned.

  The (meth) acrylic acid ester containing a hydroxyl group is not particularly limited as long as it reacts with a (meth) acrylic acid ester containing an isocyanate group described later and a (meth) acrylic acid ester containing a glycidyl group. Not, for example, hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxypentyl (meth) acrylate, (meth) acrylic acid Examples include hydroxyhexyl, hydroxyheptyl (meth) acrylate, hydroxyoctyl (meth) acrylate, and structural isomers thereof.

  The above copolymer having at least (meth) acrylic acid and a hydroxyl group-containing (meth) acrylic acid ester as a structural unit may contain other polymerizable monomers. Examples of other polymerizable monomers include (meth) acrylic acid alkyl esters.

  The (meth) acrylic acid ester containing an isocyanate group is not particularly limited as long as it reacts with a copolymer having at least (meth) acrylic acid and a hydroxyl group-containing (meth) acrylic acid ester as a structural unit. Isocyanate methyl methacrylate, 2-isocyanate ethyl methacrylate, 2-isocyanate ethyl acrylate, 2-isocyanate propyl methacrylate, 2-isocyanate octyl acrylate, p-isopropenyl-α, α-dimethylbenzyl isocyanate, m-iso Propenyl-α, α-dimethylbenzyl isocyanate, p-ethylenyl-α, α-dimethylbenzyl isocyanate, m-ethylenyl-α, α-dimethylbenzyl isocyanate, etc. can be used. The Among these, 2-isocyanate ethyl (meth) acrylate, isocyanate methyl methacrylate and the like are preferable.

  A copolymer having at least a (meth) acrylic acid ester containing (meth) acrylic acid and a hydroxyl group as a structural unit and a (meth) acrylic acid ester containing an isocyanate group are allowed to react under normal reaction conditions. Good.

  Moreover, it is preferable that the binder polymer which is the component (A) in the present embodiment contains styrene or a styrene derivative as a polymerizable monomer from the viewpoint of improving the resolution.

  When the above styrene or styrene derivative is used as a copolymerization component, the content thereof (ratio of styrene or styrene derivative to the total polymerizable monomer used) is (A) from the viewpoint of improving resolution. It is preferable to contain 15-80 mass% with respect to solid content, It is more preferable to contain 20-60 mass%, It is especially preferable to contain 30-50 mass%. When the content is less than 15% by mass, the resolution tends to be inferior, and when it exceeds 80% by mass, the development time tends to be long.

  The acid value of the component (A) is preferably 20 mgKOH / g or more, more preferably 40 mgKOH / g or more, and further preferably 60 mgKOH / g or more in terms of excellent resolution. In terms of excellent developer resistance and adhesion, it is preferably 250 mgKOH / g or less, more preferably 240 mgKOH / g or less, further preferably 230 mgKOH / g or less, and 220 mgKOH / g or less. It is particularly preferred. In addition, when developing with a solvent as a developing process, it is preferable to suppress the usage-amount of the polymerizable monomer which has a carboxyl group, and to prepare (A) component.

  Here, the acid value can be measured as follows. That is, first, about 1 g of a resin solution whose acid value is to be measured is precisely weighed, and then 30 g of acetone is added to this resin solution to dissolve it uniformly. Next, an appropriate amount of phenolphthalein as an indicator is added to the solution, and titration is performed using a 0.1N aqueous KOH solution. And an acid value is computed by following Formula.

A = 10 × Vf × 56.1 / (Wp × I)
In the formula, A represents the acid value (mgKOH / g), Vf represents the titration amount (mL) of a 0.1N KOH aqueous solution, Wp represents the mass (g) of the measured resin solution, and I was measured. The ratio (mass%) of the non volatile matter in a resin solution is shown.

  The weight average molecular weight of the component (A) is preferably 20,000 or more, more preferably 25,000 or more, and further preferably 30,000 or more from the viewpoint of excellent developer resistance. . From the viewpoint of shortening the development time, it is preferably 300,000 or less, more preferably 150,000 or less, and even more preferably 100,000 or less. The weight average molecular weight of the binder polymer is measured by gel permeation chromatography and converted using a standard polystyrene calibration curve. The measurement conditions for gel permeation chromatography (GPC) are the same as in the examples.

  Moreover, when (A) component contains the structural unit derived from the (meth) acrylic-acid alkylester, the content rate is 1-30 mass%, 2-15 mass based on the solid content whole quantity of (A) component. %, Or 3 to 10% by mass. This content is 1% by mass or more, and it is possible to suppress the peeling piece from increasing with an increase in mass and to prevent the peeling time from increasing. When it is 30% by mass or less, the resolution is improved. In the photosensitive resin composition of the present embodiment, as the component (A), one type of binder polymer may be used alone, or two or more types 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.

  The content rate of (A) component in the photosensitive resin composition of this embodiment is 20-90 mass%, 30-80 mass%, or 40-65 mass% on the basis of the photosensitive resin composition solid content whole quantity. It may be. There exists a tendency for the moldability of a film to be excellent in this content rate being 20 mass% or more. Moreover, there exists a tendency which is excellent in a sensitivity and resolution in it being 90 mass% or less.

((B) Photopolymerizable compound)
The photopolymerizable compound of the component (B) used in the present embodiment has at least one ethylenically unsaturated bond, and is a bisphenol type (meta) from the viewpoint of improving resolution and peeling properties after curing. It preferably contains at least one acrylate compound. Among bisphenol type (meth) acrylate compounds, it is more preferable to contain a bisphenol A type (meth) acrylate compound. Examples of the bisphenol A type (meth) acrylate compound include 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxypolypropoxy). ) Phenyl) propane, 2,2-bis (4-((meth) acryloxypolybutoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane, etc. Can be mentioned. Among these, 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane is preferable from the viewpoint of further improving the resolution and peeling properties.

  Among these, as commercially available products, for example, 2,2-bis (4-methacryloxypolyethoxyphenyl) propane is BP-2EM (product name, manufactured by Kyoeisha Chemical Co., Ltd.), 2,2 -Bis (4-((meth) acryloxydipropoxy) phenyl) propane is BPE-200 (manufactured by Shin-Nakamura Chemical Co., Ltd., product name), 2,2-bis (4- (methacryloxypentaethoxy) phenyl ) Examples of propane include BPE-500 (manufactured by Shin-Nakamura Chemical Co., Ltd., product name) or FA-321M (manufactured by Hitachi Chemical Co., Ltd., product name). These bisphenol A type (meth) acrylate compounds are used alone or in any combination of two or more.

  The content of the bisphenol type (meth) acrylate compound is preferably 40 to 95% by mass, more preferably 50 to 90% by mass, and 60 to 90% by mass with respect to the total amount of the component (B). Is more preferable, and it is especially preferable that it is 70-90 mass%.

  As the component (B) other than the bisphenol type (meth) acrylate compound, from the viewpoint of improving the flexibility of the cured product (cured film), at least a (poly) oxyethylene chain and a (poly) oxypropylene chain are present in the molecule. It may further contain at least one polyalkylene glycol di (meth) acrylate having one, and polyalkylene glycol di (meth) having both (poly) oxyethylene chain and (poly) oxypropylene chain in the molecule. An acrylate may further be included. Examples of the polyalkylene glycol di (meth) acrylate include FA-023M (manufactured by Hitachi Chemical Co., Ltd., product name), FA-024M (manufactured by Hitachi Chemical Co., Ltd., product name), NK ester HEMA-9P (Shin Nakamura Chemical Co., Ltd.). Product name). These can be used alone or in combination of two or more.

  Other examples of the component (B) include nonylphenoxypolyethyleneoxyacrylate, phthalic acid compounds, (meth) acrylic acid polyol esters, (meth) acrylic acid alkyl esters, and the like. Among these, at least one selected from nonylphenoxypolyethyleneoxyacrylate and a phthalic acid-based compound may be included from the viewpoint of improving the resolution, adhesion, resist shape, and peeling property after curing in a well-balanced manner. However, since the refractive index of these compounds is relatively low, from the viewpoint of improving the resolution, the content thereof is 5 to 50% by mass or 10 to 30% by mass in the total mass of the component (B). %.

  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, among which [gamma] -chloro- [beta] -hydroxypropyl- [beta]-(meth) acryloyloxyethyl-o- Phthalate may be used. γ-Chloro-β-hydroxypropyl-β′-methacryloyloxyethyl-o-phthalate is commercially available as FA-MECH (manufactured by Hitachi Chemical Co., Ltd., product name).

Moreover, you may contain a (meth) acrylic-acid polyol from a viewpoint of improving a sensitivity and reducing soaking. Examples of the (meth) acrylic acid polyol ester include trimethylolpropane polyethoxytri (meth) acrylate, trimethylolpropane polypropoxytri (meth) acrylate, trimethylolpropane polybutoxytri (meth) acrylate, and trimethylolpropane polyethoxy. Polypropoxytri (meth) acrylate, trimethylolethane polyethoxytri (meth) acrylate, trimethylolethane polypropoxytri (meth) acrylate, trimethylolethanepolybutoxytri (meth) acrylate, trimethylolethane polyethoxypolypropoxytri ( (Meth) acrylate, pentaerythritol polyethoxytri (meth) acrylate, pentaerythritol polypropoxytri (meth) acrylate Rate, 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.

  The content of the component (B) is preferably 20 to 60 parts by mass and more preferably 30 to 55 parts by mass with respect to 100 parts by mass of the total amount of the components (A) and (B). More preferably, it is 35-50 mass parts. When the content of the component (B) is in this range, in addition to the resolution and adhesion of the photosensitive resin composition and the resist skirt generation property, the photosensitivity and the coating property become better.

((C) Photopolymerization initiator)
(C) Although there is no restriction | limiting in particular as a component, You may contain the acridine compound which has a hexaaryl biimidazole derivative or one or more acridinyl groups at the point which improves a sensitivity and resolution with sufficient balance. In particular, when the photosensitive layer is exposed using actinic rays having a wavelength of 390 to 420 nm, an acridine compound having one or more acridinyl groups may be contained from the viewpoints of sensitivity and adhesion.

  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) -bi Examples include imidazole and 2,2′-bis- (2,5-difluorophenyl) -4,4 ′, 5,5′-tetrakis- (3-methoxyphenyl) -biimidazole. Among these, 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer is preferable from the viewpoints of sensitivity and resolution.

  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, 1,1 -Bis (9-acridinyl) octadecane, bis (9-acridinyl) alkanes such as 1,20-bis (9-acridinyl) eicosane, 1,3-bis (9-acridinyl) -2-oxapropane, 1,3- Bis (9-acridinyl) -2-thiapropane, 1,5-bis (9-acridinyl) -3-thiapentane and the like can be mentioned. These are used alone or in combination of two or more.

  Examples of other photopolymerization initiators include benzophenones such as 4,4′-bis (diethylamino) benzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2- Aromatic ketones such as methyl-1- [4- (methylthio) phenyl] -2-morpholino-propanone-1, quinones such as alkylanthraquinones, benzoin ether compounds such as benzoin alkyl ether, benzoin compounds such as benzoin and alkylbenzoin Benzyl derivatives such as benzyldimethyl ketal, N-phenylglycine, N-phenylglycine derivatives, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine Oxide etc. Acylphosphine oxide photoinitiator, 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], ethanone, 1- [9-ethyl-6- (2 Examples include oxime ester compounds such as -methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxime). These may be used by mixing with a hexaarylbiimidazole derivative or an acridine compound.

  The content rate of (C) component may be 0.1-10 mass%, 1-5 mass%, or 2-4.5 mass% on the basis of the photosensitive resin composition solid content whole quantity. With this content, it tends to be easy to improve both the photosensitivity and the resolution in a balanced manner.

((D) Compound having a mercapto group)
Examples of the compound having a mercapto group as component (D) of the present embodiment include 1,2-ethanedithiol, 1,3-propanedithiol, 1,4-butanedithiol, 2,3-butanedithiol, 1,5- Pentanedithiol, 1,6-hexanedithiol, 1,9-nonanedithiol, 2,3-dimercapto-1-propanol, dithioerythritol, 2,3-dimercaptosuccinic acid, 1,2-benzenedithiol, 1,3- Benzenedimethanethiol, 1,4-benzenedimethanethiol, 3,4-dimercaptotoluene, 4-chloro-1,3-benzenedithiol, 1,4-benzenedimethanethiol, 3,4-dimercaptotoluene, 4-chloro-1,3-benzenethiol, 2,4,6-trimethyl-1,3-benzenedimethanethio 4,4'-thiodiphenol, 2-hexylamino-4,6-dimercapto-1,3,5-triazine, 2-diethylamino-4,6-dimercapto-1,3,5-triazine, 2- Cyclohexylamino-4,6-dimercapto-1,3,5 triazine, 2-di-n-butylamino-4,6-dimercapto-1,3,5-triazine, ethylene glycol bis (3-mercaptopropionate) , Butanediol bisthioglycolate, ethylene glycol bisthioglycolate, 2,5-dimercapto-1,3,4-thiadiazole, 2,2 ′-(ethylenedithio) diethanethiol, 2,2-bis (2- Bifunctional thiol compounds such as hydroxy-3-mercaptopropoxyphenylpropane), 1,2,6-hexanetrithiolate Thioglycolate, 1,3,5-trithiocyanuric acid, trimethylolpropane tris (3-mercaptopropionate), trimethylolpropane tristhioglycolate, 1,3,5-tris (3-mercaptobutyloxyethyl)- Examples include trifunctional thiol compounds such as 1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, and tetrafunctional thiol compounds such as pentaerythritol tetrakis (3-mercaptobutyrate).

Among these, as the component (D), a compound having a secondary thiol or a tertiary thiol is preferable in terms of excellent stability of the curing reaction of the photosensitive resin composition. Furthermore, it is preferable to contain a bifunctional thiol compound, a trifunctional thiol compound, or a tetrafunctional thiol compound in terms of excellent bottom curability.
Thus, 1,2,6-hexanetrithiol trithioglycolate, 1,3,5-trithiocyanuric acid, trimethylolpropane tris (3-mercaptopropionate), trimethylolpropane tristhioglycolate, 1,3, Trifunctional thiol compounds such as 5-tris (3-mercaptobutyloxyethyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, pentaerythritol tetrakis (3-mercaptobutyrate) Particularly preferred are tetrafunctional thiol compounds such as Examples of commercially available products include Karenz MT PE1, Karenz MT NR1 (manufactured by Showa Denko KK, product name, “Karenz” is a registered trademark), and the like.

It is preferable that the compounding quantity of (D) component in the photosensitive resin composition is 0.001-5 mass parts with respect to 100 mass parts of total amounts of (A) component and (B) component, and 0.01-3. It is more preferable that it is a mass part, and it is still more preferable that it is 0.1-1 mass part. If the blending amount is less than 0.001 part by mass, the expected improvement in sensitivity, resolution, bottom curability, and adhesion tend to be difficult to obtain. There is a tendency that a resist pattern having a good shape as desired is not obtained, such as an increase in line width. (D) The compound containing the mercapto group which is a component is used individually by 1 type or in combination of 2 or more types.
Although the expression mechanism of the effect of the photosensitive resin composition of the present embodiment is not clear, it is considered that the bottom curability is improved by the action of the ene-thiol reaction by the component (D); a compound having a mercapto group, Furthermore, (E) sensitizer; it is presumed that the bottom curability is further improved by using in combination with a compound having an anthracene skeleton.

((E) sensitizer)
The photosensitive resin composition 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 In the present embodiment, a compound having an anthracene skeleton that is an anthracene is used. Anthracenes and other sensitizers may be used in combination.

  The content of the sensitizer may be 0.01 to 10% by mass, 0.05 to 5% by mass, or 0.1 to 3% by mass based on the total solid content of the photosensitive resin composition. . When the content 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.

(Hydrogen donor)
The photosensitive resin composition may further include a hydrogen donor. Thereby, the sensitivity of the photosensitive resin composition is further improved. Examples of the hydrogen donor include bis [4- (dimethylamino) phenyl] methane, bis [4- (diethylamino) phenyl] methane, N-phenylglycine, and leucocrystal violet. These are used individually by 1 type or in combination of 2 or more types.

  When a hydrogen donor is included, the content may be 0.01 to 10% by mass, 0.05 to 5% by mass, or 0.1 to 2% by mass. A sensitivity improves more because this content is 0.01 mass% or more. Moreover, it is suppressed that an excess hydrogen donor 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. Other components include, for example, photopolymerizable compounds having at least one cationically polymerizable cyclic ether group in the molecule (such as oxetane compounds), cationic polymerization initiators, dyes such as malachite green, tribromophenyl sulfone, light Adhesion imparting of color formers, thermochromic inhibitors, plasticizers such as p-toluenesulfonamide, polymerization inhibitors such as tert-butylcatechol, pigments, fillers, antifoaming agents, flame retardants, stabilizers, benzotriazole, etc. Agents, leveling agents, peeling accelerators, antioxidants, fragrances, imaging agents, and thermal crosslinking agents. These are used individually by 1 type or in combination of 2 or more types. Moreover, about 0.01-20 mass% may be sufficient as content of these other components, respectively.

  The photosensitive resin composition for laser direct drawing exposure may contain at least one organic solvent in order to improve the handleability of the photosensitive resin composition or to adjust the viscosity and storage stability. . 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. For example, the component (A), the component (B), the component (C), the component (D), and the component (E) are dissolved in the organic solvent to obtain 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”). The “solid content” refers to the non-volatile content excluding volatile substances such as water and solvent in the adhesive composition. That is, it refers to components other than the solvent that remains without being volatilized in the drying step, and includes liquid, water tank-like and wax-like substances 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 above-described photosensitive resin composition for laser direct drawing exposure. When using the photosensitive element of this embodiment, you may expose, without peeling a support body (support film), after laminating | stacking a photosensitive layer on a board | substrate. The photosensitive element 1 according to the present embodiment includes a support 2 and the photosensitive resin composition for laser direct drawing exposure formed on the support 2 as shown in a schematic cross-sectional view of an example in FIG. And a photosensitive layer 3 derived therefrom, and other layers such as a protective layer 4 provided as necessary.

(Support)
As the support, a polymer film (support film) having heat resistance and solvent resistance such as polyester such as polyethylene terephthalate (PET), polyolefin such as polypropylene and polyethylene can be used. Among these, a PET film may be used because it is easily available and has excellent handling properties in the manufacturing process (particularly heat resistance, heat shrinkage, and breaking strength).

  The haze of the support film may be 0.01 to 1.0%, or 0.01 to 0.5%. If the haze is 0.01% or more, the support film itself tends to be easily produced, and if it is 1.0% or less, there is a tendency to reduce minute defects that may occur in the resist pattern. Here, “haze” means cloudiness. The haze in the present embodiment refers to a value measured using a commercially available haze meter (turbidimeter) in accordance with a method defined in JIS K7105 (plastic optical property test method). The haze can be measured with a commercially available turbidimeter such as NDH-5000 (manufactured by Nippon Denshoku Industries Co., Ltd.).

Further, the particles having a diameter of 5 μm or more contained in the support film may be 5 particles / mm ² or less, and may be a support film containing particles. Thereby, while improving the slipperiness of the support film surface, suppression of the light scattering at the time of exposure can be balanced and resolution and adhesiveness can be improved. The average particle diameter of the particles is 5 μm or less, may be 1 μm or less, and particularly may be 0.1 μm or less. The lower limit value is not particularly limited, but may be 0.001 μm or more.

  As such a commercially available support film, for example, “QS-48” (product name, manufactured by Toray Industries, Inc., which is a biaxially oriented PET film having a three-layer structure containing particles in the outermost layer). ), “FB-40” (manufactured by Toray Industries, Inc., product name), “HTF-01” (manufactured by Teijin DuPont Films, Inc., product name), two-layer structure having a layer containing particles on one side. Examples thereof include axially oriented PET film “A-1517” (product name, manufactured by Toyobo Co., Ltd.).

  The support may have a thickness of 1 to 100 μm, 5 to 50 μm, or 5 to 30 μm. It can suppress that a support body is torn when it peels a support body by being 1 micrometer or more. Moreover, it can suppress that resolution falls because it is 100 micrometers or less.

(Protective layer)
The photosensitive element may further include a protective layer as necessary. As the protective layer, a film in which the adhesive force between the photosensitive layer and the protective layer is smaller than the adhesive force between the photosensitive layer and the support may be used, and a film with a low fish eye may be used. It may be used. Specifically, what can be used as a support body mentioned above is mentioned, for example. From the viewpoint of peelability from the photosensitive layer, a polyethylene film may be used. Although the thickness of a protective layer changes with uses, about 1-100 micrometers may be sufficient.

<Method for producing photosensitive element>
The photosensitive element can be manufactured as follows, for example. Manufacturing by a manufacturing method including preparing the coating liquid described above, coating the coating liquid on a support to form a coating layer, and drying the coating layer to form a photosensitive layer. can do.
The application of the coating solution onto the support can be performed by a known method such as roll coating, comma coating, gravure coating, air knife coating, die coating, or bar coating.

  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. For example, you may carry out at 70-150 degreeC for about 5 to 30 minutes. After drying, the amount of the remaining organic solvent in the photosensitive layer may be 2% by mass or less from the viewpoint of preventing diffusion of the organic solvent in the subsequent step.

  Although the thickness of the photosensitive layer in the said photosensitive element can be suitably selected according to a use, 1-100 micrometers, 1-50 micrometers, or 5-40 micrometers may be sufficient by the thickness after drying. By being 1 μm or more, industrial coating becomes easy and productivity is improved. Moreover, adhesiveness and resolution improve by being 100 micrometers or less.

  The transmittance of the photosensitive layer with respect to ultraviolet rays may be 5 to 75%, 10 to 65%, or 15 to 55% with respect to ultraviolet rays having a wavelength of 365 nm. Adhesiveness improves more because it 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 (product name, manufactured by Hitachi, Ltd.).

  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 conductor pattern by plating from a viewpoint of resolution.

<Method for forming resist pattern>
The resist pattern forming method of the present embodiment includes (i) a step of forming a photosensitive layer on a circuit forming substrate using the photosensitive resin composition for laser direct drawing exposure or the photosensitive element ( Photosensitive layer forming step), (ii) at least part (predetermined portion) of the photosensitive layer is irradiated with actinic rays to form a photocured portion (exposure step), and (iii) the circuit forming substrate. And a step (developing step) for removing at least a part other than the photocured portion, and may include other steps as necessary. The resist pattern can be said to be a photocured product pattern or a relief pattern of the photosensitive resin composition. The resist pattern forming method can also be said to be a method for manufacturing a substrate with a resist pattern.

((I) Photosensitive layer forming step)
As a method of forming a photosensitive layer on a circuit forming substrate, for example, the photosensitive resin composition for laser direct drawing exposure may be applied and dried, or after removing the protective layer from the photosensitive element The photosensitive layer of the photosensitive element may be pressure-bonded to the substrate while being heated. When a photosensitive element is used, a laminate comprising a substrate, a photosensitive layer, and a support, and these are sequentially laminated is obtained.
The circuit forming substrate is not particularly limited, but usually a circuit forming substrate provided with an insulating layer and a conductor layer formed on the insulating layer, or a die pad such as an alloy substrate (lead frame substrate). Used.

When using a photosensitive element, it is preferable to carry out under reduced pressure from the viewpoint of adhesiveness and followability. The photosensitive layer and / or the substrate may be heated at a temperature of 70 to 130 ° C. during the pressure bonding. The pressure bonding may be 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 process)
In the exposure step, at least a part of the photosensitive layer formed on the substrate is irradiated with actinic rays, whereby the portion irradiated with actinic rays is photocured to form a latent image.
At this time, when the support existing on the photosensitive resin layer is transparent to actinic rays, the support (support film) can be irradiated with actinic rays through the support (support film). In the case of light-shielding, the photosensitive resin layer is irradiated with actinic rays after removing the support (support film).

Examples of the exposure method include a method of irradiating actinic rays in an image form by a laser direct drawing method such as LDI (laser direct imaging) or DLP (Digital Light Processing) exposure method.
Further, a method (mask exposure method) in which an actinic ray is irradiated in an image form through a negative or positive mask pattern called an artwork may be employed. Further, a method of irradiating an image with an actinic ray by a projection 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 rays and visible light.

((Iii) Development process)
In the development step, at least a part of the photosensitive layer other than the photocured portion is removed from the substrate, whereby a resist pattern is formed on the substrate.

  If a support (support film) is present on the photosensitive layer, the support (support film) is removed, and then removal (development) of regions other than the photocured portion (also referred to as unexposed portions) I do. 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 battle method, a spray method, brushing, slapping, scrubbing, rocking immersion, and the like. From the viewpoint of improving resolution, a high-pressure spray method may be used. . 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. Examples thereof include an alkaline aqueous solution and an organic solvent developer.

  From the standpoint of safety and stability and good operability, an alkaline aqueous solution may be used as the developer. 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; borax, sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl- 1,3-propanediol, 1,3-diaminopropanol-2, morpholine and the like are used.

Examples of the alkaline aqueous solution used for development include a dilute solution of 0.1 to 5% by mass of sodium carbonate, a dilute solution of 0.1 to 5% by mass of potassium carbonate, a dilute solution of 0.1 to 5% by mass of sodium hydroxide, A dilute solution of 1 to 5 mass% sodium tetraborate or the like can be used. The pH of the alkaline aqueous solution used for development may be in the range of 9 to 11, and the temperature can be adjusted according to the alkali developability of the photosensitive layer. In the alkaline aqueous solution, for example, a surfactant, an antifoaming agent, a small amount of an organic solvent for promoting development, and the like may be mixed. Examples of the organic solvent used in the alkaline aqueous solution include acetone, ethyl acetate, alkoxyethanol having an alkoxy group having 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and Examples include diethylene glycol monobutyl ether.
Examples of the organic solvent used in the organic solvent developer include 1,1,1-trichloroethane, N-methylpyrrolidone, N, N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, and γ-butyrolactone. To prevent ignition, these organic solvents may be added with water so as to be in the range of 1 to 20% by mass to obtain an organic solvent developer.

In the method for forming a resist pattern in the present embodiment, after removing an uncured portion in the development step, heating at about 60 to 250 ° C. or exposure at about 0.2 to 10 J / cm ² is performed as necessary. Thus, a step of further curing the resist pattern may be included.

<Method for manufacturing printed wiring board>
The method for manufacturing a printed wiring board according to the present embodiment includes a step of forming a conductor pattern by etching or plating a substrate on which a resist pattern is formed by the resist pattern forming method. You may comprise including other processes, such as a pattern removal process.

In the plating process, a plating process is performed on the conductor layer provided on the substrate using the resist pattern formed on the substrate as a mask. After the plating treatment, the resist may be removed by removing a resist pattern, which will be described later, and the conductor layer covered with the resist may be etched to form a conductor pattern. The plating treatment method may be electrolytic plating treatment, electroless plating treatment, or electroless plating treatment.
Plating treatment includes copper plating such as copper sulfate plating, copper pyrophosphate plating, solder plating such as high-throw solder plating, watt bath (nickel sulfate-nickel chloride) plating, nickel plating such as nickel sulfamate, hard gold plating, soft Examples thereof include gold plating such as gold plating.
In the etching process, using the resist pattern formed on the substrate as a mask, the conductor layer provided on the substrate is removed by etching to form a conductor pattern. The etching method is appropriately selected according to the conductor layer to be removed. Examples of the etching solution include cupric chloride solution, ferric chloride solution, alkaline etching solution, hydrogen peroxide-based etching solution, and the like.

  After the etching process or the plating process, the resist pattern on the substrate may be removed. The resist pattern can be removed by, for example, a stronger alkaline aqueous solution than the alkaline aqueous solution used in the development step. 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.

  When the resist pattern is removed after the plating treatment, a desired printed wiring board can be manufactured by further etching the conductor layer covered with the resist by the etching treatment to form a conductor pattern. The etching method at this time is appropriately selected according to the conductor layer to be removed. For example, the above-described etching solution can be applied.

  The printed wiring board manufacturing method according to the present embodiment can be applied not only to a single-layer printed wiring board but also to a multilayer printed wiring board, and also to a printed wiring board having a small-diameter through hole. Is possible.

  Hereinafter, the objects and advantages of the present invention will be specifically described by way of examples. However, 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))
As a comonomer, 135 g of methacrylic acid, 25 g of methyl methacrylate, 115 g of benzyl methacrylate and 225 g of styrene and 1.5 g of azobisisobutyronitrile were mixed to prepare a solution a. Further, 1.2 g of azobisisobutyronitrile was dissolved in 100 g of a mixed solution (mass ratio 6: 4) of 60 g of methyl cellosolve and 40 g of toluene to prepare a solution b.

  Meanwhile, 400 g of a mixture of methyl cellosolve and toluene having a mass ratio of 6: 4 (hereinafter referred to as “mixture x”) was added to a flask equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel and a nitrogen gas introduction tube. The mixture was stirred while blowing nitrogen gas and heated to 80 ° C.

  The solution a was dropped into the mixture x in the flask at a constant dropping rate over 4 hours, and then stirred at 80 ° C. for 2 hours. Next, the solution b was dropped into the solution in the flask at a constant dropping rate over 10 minutes, and then the solution in the flask was stirred at 80 ° C. for 3 hours. Further, the temperature of the solution in the flask was raised to 90 ° C. over 30 minutes, kept at 90 ° C. for 2 hours, and then cooled to room temperature to obtain a solution of the binder polymer (A-1). Acetone was added to the binder polymer (A-1) solution to prepare a nonvolatile component (solid content) of 50% by mass. In addition, the room temperature in a present Example means 25 degreeC.

  The weight average molecular weight of the binder polymer (A-1) was 50,000, and the acid value was 163 mgKOH / g. 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 (above, manufactured by Hitachi Chemical Co., Ltd.)
Eluent: Tetrahydrofuran Measurement temperature: 40 ° C
Flow rate: 2.05 mL / min Detector: Hitachi L-3300 type RI (manufactured by Hitachi, Ltd.)

<Examples 1-4 and Comparative Examples 1-5>
[Preparation of photosensitive resin composition for laser direct drawing exposure]
(A) Binder polymer obtained by the above method, (B) a photopolymerizable compound, (C) a photopolymerization initiator, (D) a compound having a mercapto group, and (E) an anthracene skeleton as a sensitizer. The photosensitive resin composition was prepared by mixing the compound having the above and other components in a blending amount (number of blending parts) shown in Table 2 below. 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)
* 1: FA-024M: (PO) (EO) (PO) -modified polyethylene glycol dimethacrylate [manufactured by Hitachi Chemical Co., Ltd., product name]
* 2: FA-321M: 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane (product name, manufactured by Hitachi Chemical Co., Ltd.)
* 3: BP-2EM: ethoxylated bisphenol A dimethacrylate (EO, 2.6 mol modified) [manufactured by Kyoeisha Chemical Co., Ltd., product name]
((C) Photopolymerization initiator)
* 4: B-CIM: 2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole (product name, manufactured by Hampford)
((D) Mercapto group-containing compound)
* 5: NR1: 1,3,5-tris (3-mercaptobutyloxyethyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione [manufactured by Showa Denko KK product name]
* 6: PE1: Pentaerythritol tetrakis (3-mercaptobutyrate) [Product name, manufactured by Showa Denko KK]
* 7: BD1: 1,4-bis (3-mercaptobutyryloxy) butane [Product name, manufactured by Showa Denko KK]
((E) sensitizer)
(Compound having anthracene skeleton)
* 8: DBA: 9,10-di (n-butoxy) anthracene [product name, manufactured by Kawasaki Kasei Kogyo Co., Ltd.]
* 9: BHP-A: 9,10-bis (3-hydroxy-5-butoxy) anthracene [product name, manufactured by Kawasaki Kasei Kogyo Co., Ltd.]
(Compound without anthracene skeleton)
* 10: PZ-501D: 1-phenyl-3- (4-methoxystyryl) -5- (4-methoxyphenyl) pyrazoline [manufactured by Nippon Chemical Industry Co., Ltd., product name]
(Other)
* 11: TBC: tert-butylcatechol [product name, manufactured by Wako Pure Chemical Industries, Ltd.]
* 12: SF-808H: Benzotriazole derivative [manufactured by Sanwa Kasei Kogyo Co., Ltd., product name]
* 13: FA-711MM: Pentamethylpiperidyl methacrylate [manufactured by Hitachi Chemical Co., Ltd., product name]

<Preparation of photosensitive element>
The photosensitive resin composition for laser direct drawing exposure obtained above was applied on a support film (support) shown below so as to have a uniform thickness. Subsequently, it was dried with a hot air convection dryer at 80 ° C. and 120 ° C. to form a photosensitive layer having a dried film thickness of 25 μm.

FB-40: PET film [haze: 0.4%, thickness: 16 μm, (product name, manufactured by Toray Industries, Inc.)
A polyethylene film (protective layer) (“NF-15” manufactured by Tamapoly Co., Ltd., product name) is laminated on the photosensitive layer to obtain a photosensitive element in which a support, a photosensitive layer, and a protective layer are sequentially laminated. It was.

<Production of laminate>
A copper-clad laminate (substrate “MCL-E-67”, manufactured by Hitachi Chemical Co., Ltd., product name), which is a glass epoxy material in which copper foil (thickness: 12 μm) is laminated on both sides, is washed with water, pickled and washed with air. Dried in a stream. Thereafter, the copper-clad laminate was heated to 80 ° C., and the photosensitive element obtained above was laminated so that the photosensitive layer was in contact with the copper surface while peeling off the protective layer. Thus, a laminate (test substrate) 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. The lamination was performed using a heat roll at 110 ° C. with a pressure of 0.4 MPa and a roll speed of 1.0 m / min.

<Evaluation>
(Evaluation of light sensitivity)
A Hitachi 41-step tablet (manufactured by Hitachi Chemical Co., Ltd., showing the exposure amount at the recommended number of curing steps) is placed on the test substrate, and a DLP exposure machine (“DE-1UH” Hitachi) having a wavelength of 405 nm using a semiconductor laser as a light source. The photosensitive layer was exposed with a predetermined amount of energy using a product manufactured by Via Mechanics Co., Ltd.

Next, the support film 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 treatment, the amount of energy (mJ / cm ² ) at which the number of steps of the step tablet of the photocured film formed on the substrate was 15.0 was determined, and the photosensitivity of the photosensitive resin composition was evaluated. The results are shown in Table 3. In addition, it shows that a sensitivity is so high that this figure is small.

(Evaluation of resolution and adhesion)
On the support of the test piece obtained above, as a negative for resolution and adhesion evaluation, a glass chrome type phototool (resolution negative: line width / space width x / x (x: 1 to 30). , Unit: μm), adhesive negative: line width / space width y / 3y (y: 1-30, unit: μm) wiring pattern, Hitachi 41 stages The exposure was performed with an energy amount such that the number of steps remaining after development of the step tablet was 15.0. After the exposure, it was developed in the same manner as in the photosensitivity measurement test.

  After the development process, the space portion (unexposed portion) is removed cleanly, and the line portion (exposed portion) is formed without meandering or chipping. The resolution (space width) and adhesion (line width) were evaluated. The results are shown in Table 3. A smaller value means better resolution (resolution) and adhesion.

  As shown in Table 3, it can be seen that Examples 1-4 have higher photosensitivity than Comparative Examples 1-5, and are excellent in resolution and adhesion.

  ADVANTAGE OF THE INVENTION According to this invention, the photosensitive resin composition for laser direct drawing exposure which is excellent in the resolution, adhesiveness, and resist stripping suppression, the photosensitive element using the same, the formation method of a resist pattern, and the printed wiring board A manufacturing method can be provided, and a lead frame manufacturing method using the same can also be provided.

DESCRIPTION OF SYMBOLS 1 ... Photosensitive element 2 ... Support body 3 ... Photosensitive layer 4 ... Protective layer

Claims (6)

  Laser direct drawing containing (A) binder polymer, (B) photopolymerizable compound, (C) photopolymerization initiator, (D) compound having mercapto group and (E) compound having anthracene skeleton as sensitizer Photosensitive resin composition for exposure.   The photosensitive resin composition for laser direct drawing exposure of Claim 1 in which the compound which has the mercapto group of the said (D) component contains the compound which has secondary thiol or tertiary thiol.   A photosensitive element comprising: a support; and a photosensitive layer formed on the support using the photosensitive resin composition for laser direct drawing exposure according to claim 1 or 2. (I) A photosensitive layer is formed on the circuit forming substrate using the photosensitive resin composition for laser direct drawing exposure according to claim 1 or 2, or the photosensitive element according to claim 3. And a process of
(Ii) irradiating a predetermined portion of the photosensitive layer with actinic rays to form a photocured portion;
(Iii) removing at least a portion other than the photocured portion from the circuit forming substrate;
A method for forming a resist pattern.   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 claim 4.   The manufacturing method of the printed wiring board of Claim 5 further equipped with the process of removing a photocuring part after the process of forming a conductor pattern.

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