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

Abstract

A photosensitive resin composition containing (A) a binder polymer, (B) a photopolymerizable compound having at least one ethylenically unsaturated bond, and (C) a photopolymerization initiator, the (C) photopolymerization initiator including an oxime ester-based photopolymerization initiator, the content of the oxime ester-based photopolymerization initiator is 0.3 parts by mass or more with respect to 100 parts by mass of the total of (A) the binder polymer and (B) the photopolymerizable compound.

Description

Technical Field

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

[0002] In the field of printed wiring board production, photosensitive elements including a layer formed on a support using a photosensitive resin composition (hereinafter referred to as "photosensitive resin layer") are widely used as resist materials for etching, plating, and the like.

[0003] Conventionally, printed wiring boards (PCBs) have been manufactured using, for example, the aforementioned photosensitive element through the following steps. Specifically, a photosensitive resin layer of the photosensitive element is laminated onto a circuit-forming substrate (e.g., a copper-clad laminate). The photosensitive resin layer is laminated so that it closely adheres to the surface of the circuit-forming substrate that forms the conductor pattern (circuit). Furthermore, the photosensitive resin layer is thermally and pressure-bonded to the underlying circuit-forming substrate (normal pressure lamination).

[0004] Next, the desired area of ​​the photosensitive resin layer is exposed through a mask film or the like (mask exposure method). At this time, the support (support film, etc.) is peeled off at any time before or after exposure. A developer is then used to dissolve or disperse the unexposed portions of the photosensitive resin layer, forming a resist pattern consisting of the cured portions of the photosensitive resin layer. Next, etching or plating is performed to form a conductive pattern, and the resist pattern is finally peeled off.

[0005] As a method for pattern exposure, a direct drawing method (such as LDI (Lazer Direct Imaging) method) has recently become popular, in which circuit data created by CAD is directly drawn with laser light without requiring a mask film.

[0006] The direct drawing method (LDI method, etc.) does not use a mask film, so it has many advantages, such as being able to reduce the cost of the mask film, having high positioning accuracy of the opening of the resist and easy scaling correction, and not requiring management of foreign matter adhesion, contamination, and scratches on the mask film.

[0007] As a photosensitive resin composition that can be used for such a direct writing method, for example, a photosensitive resin composition containing a specific binder polymer and a specific photopolymerization initiator has been proposed (for example, refer to Patent Documents 1 and 2 listed below).

[0008] Previous technical literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Laid-Open No. 2010-217400

[0011] Patent Document 2: International Publication No. 2012 / 014580

[0012] Patent Document 3: Japanese Patent Application Laid-Open No. 11-327137 Summary of the Invention

[0013] Technical issues to be solved by the invention

[0014] In both mask exposure and direct writing methods, forming a resist pattern with high precision is necessary to form fine wiring. However, when using existing photosensitive resin compositions to form a resist pattern, there is a problem that the resist line width after exposure and development is wider than the designed value, making it easy to process.

[0015] Therefore, an object of the present invention is to provide a photosensitive resin composition capable of reducing deviations from the designed resist line width obtained when forming a resist pattern. Furthermore, an object of the present invention is to provide a photosensitive element, a cured product, a method for forming a resist pattern, and a method for manufacturing a printed wiring board using the photosensitive resin composition.

[0016] Means for solving technical problems

[0017] In order to solve the above-mentioned problems, the present invention provides the following photosensitive resin composition, photosensitive element, cured product, method for forming a resist pattern, and method for producing a printed wiring board.

[0018] [1] A photosensitive resin composition comprising (A) a binder polymer, (B) a photopolymerizable compound having at least one ethylenically unsaturated bond, and (C) a photopolymerization initiator, wherein the photopolymerization initiator (C) comprises an oxime ester-based photopolymerization initiator, and the content of the oxime ester-based photopolymerization initiator is 0.3 parts by mass or more relative to 100 parts by mass of the total of the binder polymer (A) and the photopolymerizable compound (B).

[0019] [2] The photosensitive resin composition according to [1], wherein the binder polymer (A) comprises a structural unit derived from (meth)acrylic acid and a structural unit derived from benzyl (meth)acrylate or a benzyl (meth)acrylate derivative.

[0020] [3] The photosensitive resin composition according to [1] or [2], wherein the photopolymerization initiator (C) consists solely of the oxime ester-based photopolymerization initiator.

[0021] [4] The photosensitive resin composition according to any one of [1] to [3] above, wherein the oxime ester-based photopolymerization initiator contains a compound having a carbazole structure.

[0022] [5] The photosensitive resin composition according to any one of [1] to [4] above, wherein the oxime ester-based photopolymerization initiator contains a compound having a phenyl sulfide structure.

[0023] [6] The photosensitive resin composition according to any one of [1] to [5], wherein the oxime ester-based photopolymerization initiator contains a compound having a fluorene structure.

[0024] [7] The photosensitive resin composition according to any one of [1] to [6] above, wherein the content of the oxime ester photopolymerization initiator is 3.0 parts by mass or less relative to 100 parts by mass of the total of the (A) binder polymer and the (B) photopolymerizable compound.

[0025] [8] The photosensitive resin composition according to any one of [1] to [7] above, which is used for a direct drawing method.

[0026] [9] A photosensitive element comprising a support and a photosensitive resin layer disposed on the support, wherein the photosensitive resin layer comprises the photosensitive resin composition according to any one of [1] to [8] above or a cured product thereof.

[0027]

[10] A cured product of the photosensitive resin composition according to any one of [1] to [8] above.

[0028]

[11] The cured product according to

[10] above, which is a resist pattern.

[0029]

[12] A method for forming a resist pattern, comprising the following steps: forming a photosensitive resin layer on a substrate using the photosensitive resin composition described in any one of [1] to [8] above; irradiating at least a portion of the photosensitive resin layer with active light to cure the photosensitive resin layer; and removing the uncured portion of the photosensitive resin layer from the substrate to form a resist pattern.

[0030]

[13] A method for forming a resist pattern, comprising the following steps: forming a photosensitive resin layer on a substrate using the photosensitive element described in [9] above; irradiating at least a portion of the photosensitive resin layer with active light to cure the photosensitive resin layer; and removing the uncured portion of the photosensitive resin layer from the substrate to form a resist pattern.

[0031]

[14] A method for manufacturing a printed circuit board, comprising the following steps: forming a resist pattern on the substrate by the resist pattern forming method described in

[12] or

[13] above; and performing a plating treatment or an etching treatment on a component having the substrate and the resist pattern.

[0032] Effects of the Invention

[0033] According to the present invention, a photosensitive resin composition can be provided that can reduce variations in the resist line width obtained from the designed value when forming a resist pattern. Furthermore, the present invention can provide a photosensitive element, a cured product, a method for forming a resist pattern, and a method for manufacturing a printed wiring board using the photosensitive resin composition. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic cross-sectional view showing a photosensitive element according to one embodiment of the present invention.

[0035] Figure 2 This is a perspective view schematically showing an example of a manufacturing process of a printed wiring board by a semi-additive process. DETAILED DESCRIPTION

[0036] Below, the embodiment of the present invention is described in detail. It should be understood that other embodiments can be studied and produced without departing from the scope and purpose of the present invention. Therefore, the following description of "modes for carrying out the invention" should not be understood as limiting.

[0037] In this specification, the term "process" includes not only independent processes, but also processes that cannot be clearly distinguished from other processes as long as the intended effect of the process is achieved. The numerical range represented by "~" represents a range that includes the numerical values ​​recorded before and after "~" as the minimum and maximum values, respectively. Within the numerical ranges recorded in stages in this specification, the upper limit or lower limit of the numerical range of a certain stage can also be replaced by the upper limit or lower limit of the numerical range of other stages. Within the numerical ranges recorded in this specification, the upper limit or lower limit of its numerical range can also be replaced by the values ​​shown in the embodiments. When observed as a top view, the term "layer" includes structures formed in a shape of a part in addition to structures formed in the shape of the entire surface. "(Meth)acrylic acid" means at least one of "acrylic acid" and its corresponding "methacrylic acid". The same applies to other similar expressions such as (meth)acrylate.

[0038] In this specification, when referring to the amount of each component in a composition, or when multiple substances corresponding to each component are present in a composition, unless otherwise specified, the amount refers to the total amount of the multiple substances present in the composition. In this specification, "room temperature" means 25°C. In this specification, "solid content" refers to the non-volatile components in a photosensitive resin composition, excluding volatile substances (water, solvent, etc.). In other words, it refers to components other than solvents such as water and organic solvents that do not evaporate during the drying process and also includes substances that are liquid, syrupy, and waxy at around room temperature (25°C).

[0039] "(Poly)oxyethylene" refers to an oxyethylene group or a polyoxyethylene group in which two or more oxyethylene groups are linked by an ether bond. "(Poly)oxypropylene" refers to a polyoxypropylene group or a polyoxypropylene group in which two or more oxypropylene groups are linked by an ether bond. "EO-modified" refers to a compound containing an oxyethylene group. "PO-modified" refers to a compound containing a oxypropylene group. "EO·PO-modified" refers to a compound containing both an oxyethylene group and a oxypropylene group.

[0040] <Photosensitive resin composition and cured product thereof>

[0041] The photosensitive resin composition according to this embodiment contains (A) a binder polymer (hereinafter also referred to as component (A)), (B) a photopolymerizable compound having at least one ethylenically unsaturated bond (hereinafter also referred to as component (B)), and (C) a photopolymerization initiator (hereinafter also referred to as component (C)). In the photosensitive resin composition according to this embodiment, the photopolymerization initiator (C) comprises an oxime ester-based photopolymerization initiator. In the photosensitive resin composition according to this embodiment, the content of the oxime ester-based photopolymerization initiator is 0.3 parts by mass or more relative to a total of 100 parts by mass of the binder polymer (A) and the photopolymerizable compound (B).

[0042] In the photosensitive resin composition involved in the present embodiment, 0.3 mass parts or more of an oxime ester-based photopolymerization initiator is contained as component (C) relative to 100 mass parts of the total of components (A) and (B). Therefore, in any of the methods of mask exposure and direct drawing, when forming a resist pattern, it is possible to suppress the obtained resist line width from becoming thicker or thinner than the design value, and to reduce the deviation from the obtained resist line width and the design value. In the past, when the deviation from the design value of the obtained resist line width was large, it was necessary to correct the drawing data or the mask film to take into account that the resist line width became thicker or thinner than the design value. However, by using the photosensitive resin composition involved in the present embodiment, a resist line width close to the design value can be obtained even without correction. Therefore, there is no need to correct the design value in the exposure process, or only slight correction is required, so the exposure process can be carried out efficiently.

[0043] The cured product according to this embodiment is a cured product of the photosensitive resin composition according to this embodiment. The cured product according to this embodiment may be a resist pattern.

[0044] (Component (A): Binder polymer)

[0045] As the (A) component that can be used in the photosensitive resin composition involved in this embodiment, for example, (meth) acrylic resin (resin having a structural unit derived from (meth) acrylic acid), styrene resin, epoxy resin, amide resin, amide epoxy resin, alkyd resin and phenolic resin can be mentioned. From the viewpoint of further improving alkali developability, the photosensitive resin composition involved in this embodiment may contain a (meth) acrylic resin, and the (A) component may have a structural unit derived from (meth) acrylic acid. In addition, the (A) component may have a structural unit derived from a polymerizable monomer other than (meth) acrylic acid. As such structural units, structural units derived from styrene or styrene derivatives, structural units derived from (meth) acrylic acid alkyl esters, structural units derived from benzyl (meth) acrylate or benzyl (meth) acrylate derivatives, etc. can be mentioned. From the viewpoint of improving resolution and adhesion, the (A) component preferably has at least a structural unit derived from (meth) acrylic acid and a structural unit derived from benzyl (meth) acrylate or a benzyl (meth) acrylate derivative. Furthermore, from the perspective of further improving resolution and adhesion, component (A) may include a structural unit derived from a hydroxyalkyl (meth)acrylate. Furthermore, component (A) may be composed solely of at least one structural unit selected from the group consisting of a structural unit derived from (meth)acrylic acid, a structural unit derived from styrene or a styrene derivative, a structural unit derived from an alkyl (meth)acrylate, a structural unit derived from benzyl (meth)acrylate or a benzyl (meth)acrylate derivative, and a structural unit derived from a hydroxyalkyl (meth)acrylate. Component (A) can be produced, for example, by free radical polymerization of a polymerizable monomer.

[0046] Examples of the polymerizable monomers other than (meth)acrylic acid include styrene; polymerizable styrene derivatives substituted at the α-position or in the aromatic ring, such as vinyltoluene and α-methylstyrene; alkyl (meth)acrylates; benzyl (meth)acrylate; benzyl (meth)acrylate derivatives; acrylamides such as dialkylacrylamide; acrylonitrile; esters of vinyl alcohol such as vinyl n-butyl ether; cycloalkyl (meth)acrylates; furfuryl (meth)acrylate; tetrahydrofurfuryl (meth)acrylate; isobornyl (meth)acrylate; adamantyl (meth)acrylate Ester; dicyclopentyl (meth)acrylate; dimethylaminoethyl (meth)acrylate; diethylaminoethyl (meth)acrylate; glycidyl (meth)acrylate; 2,2,2-trifluoroethyl (meth)acrylate; 2,2,3,3-tetrafluoropropyl (meth)acrylate; β-furfuryl (meth)acrylate; β-styryl (meth)acrylate; maleic acid; maleic anhydride; maleic acid monoesters such as monomethyl maleate, monoethyl maleate, and monoisopropyl maleate; fumaric acid; cinnamic acid; α-cyanocinnamic acid; methacrylic acid; crotonic acid; propiolic acid, etc.

[0047] Examples of benzyl (meth)acrylate derivatives include compounds in which an alkoxy group having 1 to 6 carbon atoms (the same shall apply hereinafter) is substituted with a halogen atom and / or an alkyl group having 1 to 6 carbon atoms in the aromatic ring of the benzyl group. Examples of benzyl (meth)acrylate derivatives include ethoxybenzyl (meth)acrylate, methoxybenzyl (meth)acrylate, chlorobenzyl (meth)acrylate, methylbenzyl (meth)acrylate, and ethylbenzyl (meth)acrylate.

[0048] From the perspective of further improving resolution and adhesion, component (A) may contain at least one structural unit derived from styrene or a styrene derivative. In this case, by further improving resolution, a more excellent resist shape can be obtained. Component (A) may contain structural units derived from styrene and structural units derived from a styrene derivative.

[0049] Examples of hydroxyalkyl (meth)acrylates include methyl hydroxy(meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxypentyl (meth)acrylate, and hydroxyhexyl (meth)acrylate. Furthermore, in the hydroxyalkyl (meth)acrylate unit, when the alkyl portion has 3 or more carbon atoms, it may have a branched structure.

[0050] From the viewpoint of improving alkali developability and stripping properties, component (A) may have at least one structural unit derived from an alkyl (meth)acrylate. Examples of the alkyl group of the alkyl (meth)acrylate include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl. As the above-mentioned alkyl group, various structural isomers may be used. Examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, and dodecyl (meth)acrylate. From the viewpoint of further improving stripping properties, the number of carbon atoms of the above-mentioned alkyl group may be 1 to 4. The alkyl (meth)acrylate may be used alone or in any combination of two or more.

[0051] The content of each structural unit constituting component (A) is not particularly limited. The content of the structural unit derived from (meth) acrylic acid may be such that the acid value of component (A) falls within the following range. From the viewpoint of being able to suppress the development time from becoming longer, the acid value of component (A) may be 100 mgKOH / g or more, 120 mgKOH / g or more, 140 mgKOH / g or more, 150 mgKOH / g or more, or 160 mgKOH / g or more. From the viewpoint of further improving the developer resistance (e.g., adhesion) of the cured product of the photosensitive resin composition, the acid value of component (A) may be 250 mgKOH / g or less, 240 mgKOH / g or less, or 230 mgKOH / g or less. From these viewpoints, the acid value of component (A) may be 100 to 250 mgKOH / g, 120 to 240 mgKOH / g, 140 to 230 mgKOH / g, 150 to 230 mgKOH / g, or 160 to 230 mgKOH / g. Furthermore, in the case of solvent development, the amount of a polymerizable monomer having a carboxyl group (monomers such as (meth)acrylic acid) may be adjusted to a small amount for excellent developability.

[0052] When component (A) has a structural unit derived from benzyl (meth)acrylate or a benzyl (meth)acrylate derivative, the content of the structural unit can be within the following ranges based on the total solid content (total mass) of component (A). From the perspective of improving the chemical resistance of the resin, the above content can be 1% by mass or more, 15% by mass or more, or 20% by mass or more. From the perspective of suppressing the prolongation of the peeling time, the above content can be 80% by mass or less, 50% by mass or less, or 40% by mass or less. From these viewpoints, the above content can be 1-80% by mass, 15-50% by mass, or 20-40% by mass.

[0053] In the case where component (A) has a structural unit derived from styrene or a styrene derivative, the content of the structural unit may be within the following ranges, based on the total solid content (total mass) of component (A). From the viewpoint of further improving the resolution, the above content may be 5% by mass or more, 10% by mass or more, 20% by mass or more, 25% by mass or more, 30% by mass or more, 35% by mass or more, 40% by mass or more, or 45% by mass or more. From the viewpoint of being able to suppress the enlargement of the peeling piece and the prolongation of the peeling time, the above content may be 65% by mass or less, 55% by mass or less, or 50% by mass or less. From these viewpoints, the above content may be 5-65% by mass, 10-55% by mass, 20-50% by mass, 25-50% by mass, 30-50% by mass, 35-50% by mass, 40-50% by mass, or 45-50% by mass.

[0054] The component (A) may have a structural unit derived from benzyl (meth)acrylate or a benzyl (meth)acrylate derivative and a structural unit derived from styrene or a styrene derivative. In this case, a resist having even better adhesion can be obtained.

[0055] In the case where component (A) has a structural unit derived from an alkyl (meth)acrylate, the content of the structural unit may be within the following ranges, based on the total solid content (total mass) of component (A). From the viewpoint of being able to suppress the enlargement of the peeling piece and the prolongation of the peeling time, the above content may be 1% by mass or more, 2% by mass or more, or 3% by mass or more. From the viewpoint of further improving the resolution and adhesion, the above content may be 80% by mass or less, 60% by mass or less, or 50% by mass or less. From these viewpoints, the above content may be 1 to 80% by mass, 2 to 60% by mass, or 3 to 50% by mass.

[0056] From the viewpoint of a tendency for the cured product of the photosensitive resin composition to have further excellent developer resistance (for example, adhesion), the weight average molecular weight (Mw) of the component (A) may be 10,000 or more, 20,000 or more, or 25,000 or more. From the viewpoint of a tendency for the developing time to be excellent, the weight average molecular weight (Mw) of the component (A) may be 100,000 or less, 80,000 or less, or 60,000 or less. From these viewpoints, the weight average molecular weight (Mw) of the component (A) may be 10,000 to 100,000, 20,000 to 80,000, or 25,000 to 60,000. In addition, the weight average molecular weight of the component (A) is measured by gel permeation chromatography (GPC) (converted by using a calibration curve of standard polystyrene). In addition, for compounds with low molecular weight, when it is difficult to measure by the above-mentioned weight average molecular weight measurement method, the molecular weight can also be measured by other methods to calculate its average value.

[0057] The dispersion degree (Mw / Mn) of the component (A) is not particularly limited, but may be 1.0 to 3.0 or 1.5 to 2.5. When the dispersion degree is 3.0 or less, adhesion and resolution are further improved.

[0058] If necessary, the component (A) may have a characteristic group (such as a nitro group) that is photosensitizing to light having a wavelength within the range of 350 to 440 nm in its molecule.

[0059] In the photosensitive resin composition involved in this embodiment, as component (A), one binder polymer can be used alone, or two or more binder polymers can be used in combination. As components (A) when used in combination with two or more binder polymers, for example, two or more binder polymers composed of different copolymer components (binder polymers containing different monomer units as copolymer components), two or more binder polymers with different weight-average molecular weights, and two or more binder polymers with different dispersities can be cited. As component (A), a polymer with a multimodal molecular weight distribution described in Japanese Patent Application Laid-Open No. 11-327137 (Patent Document 3) can also be used.

[0060] The content of component (A) may be within the following ranges based on the total solid content (total mass) of the photosensitive resin composition. From the perspective of having a tendency to have excellent film formability, the content of component (A) may be 20% by mass or more, 30% by mass or more, 40% by mass or more, or 50% by mass or more. From the perspective of having a tendency to have further excellent sensitivity and resolution, the content of component (A) may be 90% by mass or less, 80% by mass or less, 65% by mass or less, or 60% by mass or less. From these viewpoints, the content of component (A) may be 20-90% by mass, 30-80% by mass, 40-65% by mass, or 50-60% by mass.

[0061] The content of component (A) relative to the total amount of 100 parts by mass of component (A) and component (B) can be within the following ranges. From the viewpoint of further improving the formability of the film, the content of component (A) can be 30 parts by mass or more, 35 parts by mass or more, 40 parts by mass or more, or 50 parts by mass or more. From the viewpoint of further improving sensitivity and resolution, the content of component (A) can be 70 parts by mass or less, 65 parts by mass or less, or 60 parts by mass or less. From these viewpoints, the content of component (A) can be 30 to 70 parts by mass, 35 to 65 parts by mass, 40 to 60 parts by mass, or 50 to 60 parts by mass.

[0062] (Component (B): Photopolymerizable compound)

[0063] Component (B) is a compound having at least one ethylenically unsaturated bond. Component (B) can be used alone or in any combination of two or more. To further improve alkali developability, resolution, and post-curing peeling properties, component (B) may include at least one bisphenol A (meth)acrylate compound.

[0064] Examples of the bisphenol A (meth)acrylate compound include 2,2-bis(4-((meth)acryloyloxypolyethoxy)phenyl)propane, 2,2-bis(4-((meth)acryloyloxypolypropoxy)phenyl)propane, 2,2-bis(4-((meth)acryloyloxypolybutoxy)phenyl)propane, and 2,2-bis(4-((meth)acryloyloxypolyethoxypolypropoxy)phenyl)propane. Component (B) may contain 2,2-bis(4-((meth)acryloyloxypolyethoxy)phenyl)propane to further improve resolution and release properties. The bisphenol A (meth)acrylate compound may be used alone or in any combination of two or more.

[0065] Among these, 2,2-bis(4-(methacryloyloxydiethoxy)phenyl)propane is commercially available as BPE-200 (manufactured by Shin-Nakamura Chemical Co., Ltd., product name). 2,2-bis(4-(methacryloyloxypentaethoxy)phenyl)propane is commercially available as BPE-500 (manufactured by Shin-Nakamura Chemical Co., Ltd., product name) or FA-321M (manufactured by Resonac Holdings Corporation, product name).

[0066] In the photosensitive resin composition involved in this embodiment, from the viewpoint of further improving the resolution of the resist pattern, the content of the above-mentioned bisphenol A type (meth) acrylate compound can be within the following ranges based on the total solid content (total mass) of the (B) component. The above-mentioned content can be 20% by mass or more, 40% by mass or more, 60% by mass or more, or 70% by mass or more. The above-mentioned content can be 100% by mass or less, or 95% by mass or less. From these viewpoints, the above-mentioned content can be 20-100% by mass, 40-100% by mass, 60-100% by mass, or 70-100% by mass, or 20-95% by mass, 40-95% by mass, 60-95% by mass, or 70-95% by mass.

[0067] From the perspective of achieving a balanced improvement in resolution and flexibility, component (B) may include a compound obtained by reacting a polyol with an α,β-unsaturated carboxylic acid. Examples of compounds obtained by reacting a polyol with an α,β-unsaturated carboxylic acid include polyethylene glycol di(meth)acrylate having 2 to 14 vinyl groups; polypropylene glycol di(meth)acrylate having 2 to 14 propenyl groups; alkylene glycol di(meth)acrylates having both (poly)oxyethylene and (poly)oxypropylene groups; trimethylolpropane di(meth)acrylate; trimethylolpropane tri(meth)acrylate; EO-modified trimethylolpropane tri(meth)acrylate; PO-modified trimethylolpropane tri(meth)acrylate; EO / PO-modified trimethylolpropane tri(meth)acrylate; tetramethylolmethane tri(meth)acrylate; and tetramethylolmethane tetra(meth)acrylate. These can be used alone, but from the perspective of further improving resolution, two or more selected from the group consisting of compounds obtained by reacting the above-mentioned polyols with α,β-unsaturated carboxylic acids can be used in combination. When two or more are used in combination, the resolution is further improved.

[0068] The content (total amount) of the compound obtained by reacting the polyol with the α,β-unsaturated carboxylic acid can be within the following ranges, based on the total solid content (total mass) of component (B). From the perspective of improving flexibility, the content can be 5% by mass or more. From the perspective of further improving resolution, the content can be 20% by mass or less or 15% by mass or less. From these perspectives, the content can be 5-20% by mass or 5-15% by mass.

[0069] The photosensitive resin composition of the present embodiment may further contain, as component (B), other polymerizable compounds other than the above-mentioned compounds obtained by reacting the bisphenol A-type (meth)acrylate compound and the polyol with the α,β-unsaturated carboxylic acid.

[0070] Examples of other polymerizable compounds include nonylphenoxypolyoxyethylene (meth)acrylate, phthalic acid compounds, alkyl (meth)acrylates, and photopolymerizable compounds having at least one cationically polymerizable cyclic ether group in the molecule (such as oxetane compounds). Among these, from the perspective of achieving balanced improvements in resolution, adhesion, resist shape, and release properties after curing, at least one compound selected from the group consisting of nonylphenoxypolyoxyethylene (meth)acrylate and phthalic acid compounds is preferred.

[0071] Examples of the nonylphenoxypolyoxyethylene (meth)acrylate include nonylphenoxytriethyleneoxy (meth)acrylate, nonylphenoxytetraethyleneoxy (meth)acrylate, nonylphenoxypentaethyleneoxy (meth)acrylate, nonylphenoxyhexaethyleneoxy (meth)acrylate, nonylphenoxyheptaethyleneoxy (meth)acrylate, nonylphenoxyoctaethyleneoxy (meth)acrylate, nonylphenoxynonaeethyleneoxy (meth)acrylate, nonylphenoxydecaethyleneoxy (meth)acrylate, and nonylphenoxyundeethyleneoxy (meth)acrylate. The nonylphenoxypolyoxyethylene (meth)acrylate can be used alone or in any combination of two or more.

[0072] As phthalic acid compounds, for example, γ-chloro-β-hydroxypropyl-β'-(meth)acryloyloxyethyl-phthalate, β-hydroxyethyl-β'-(meth)acryloyloxyethyl-phthalate and β-hydroxypropyl-β'-(meth)acryloyloxyethyl-phthalate can be mentioned. Among them, as the phthalic acid compound, γ-chloro-β-hydroxypropyl-β'-(meth)acryloyloxyethyl-ethyl phthalate is preferred. γ-Chloro-β-hydroxypropyl-β'-methacryloyloxyethyl-phthalate can be commercially obtained as FA-MECH (manufactured by Resonac Holdings Corporation). The phthalic acid compound can be used alone or in any combination of two or more.

[0073] When the photosensitive resin composition according to the present embodiment contains the above-mentioned other photopolymerizable compound as the component (B), the content of the photopolymerizable compound may be 1 to 30% by mass, 3 to 25% by mass, or 5 to 20% by mass based on the total solid content (total mass) of the component (B) from the viewpoint of improving resolution, adhesion, resist shape, and release properties after curing in a balanced manner.

[0074] The content of component (B) may be within the following ranges based on the total solid content (total mass) of the photosensitive resin composition. From the perspective of having a tendency to be more excellent in sensitivity and resolution, the content of component (B) may be 3% by mass or more, 10% by mass or more, 25% by mass or more, 30% by mass or more, or 40% by mass or more. From the perspective of having a tendency to be excellent in film formability, the content of component (B) may be 70% by mass or less, 60% by mass or less, or 50% by mass or less. From these perspectives, the content of component (B) may be 3-70% by mass, 10-60% by mass, 25-50% by mass, 30-50% by mass, or 40-50% by mass.

[0075] The content of component (B) relative to the total amount of 100 parts by mass of component (A) and component (B) can be within the following range. From the viewpoint of further improving sensitivity and resolution, the content of component (B) can be 5 parts by mass or more, 10 parts by mass or more, 15 parts by mass or more, 20 parts by mass or more, 30 parts by mass or more, or 40 parts by mass or more. From the viewpoint of further improving the formability of the film, the content of component (B) can be 70 parts by mass or less, 65 parts by mass or less, 60 parts by mass or less, 50 parts by mass or less, or 45 parts by mass or less. From these viewpoints, the content of component (B) can be 5-70 parts by mass, 10-70 parts by mass, 15-65 parts by mass, 20-60 parts by mass, 30-50 parts by mass, or 40-45 parts by mass.

[0076] (Component (C): photopolymerization initiator)

[0077] The photosensitive resin composition according to this embodiment contains an oxime ester photopolymerization initiator as component (C). This can reduce variations in the obtained resist line width from the designed value when forming a resist pattern in either the mask exposure method or the direct writing method.

[0078] The cinnamaldehyde cinnamoyl oxime ester-based photopolymerization initiator is not particularly limited as long as it contains an oxime ester group. However, compounds having at least one of a carbazole structure, a phenyl sulfide structure, and a fluorene structure are preferred. This allows for further reduction in the deviation of the resist line width from the designed value when forming a resist pattern, even in both mask exposure and direct writing methods. Oxime ester-based photopolymerization initiators can be used alone or in any combination of two or more.

[0079] Examples of the oxime ester photopolymerization initiator having a carbazole structure include 1-propanone, 3-cyclopentyl-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(o-acetoxime) (product name "TR-PBG-304", manufactured by Changzhou Tronly New Electronic Materials Co., Ltd.), 1-propanone, 3-cyclopentyl-1-[2-(2-pyrimidinylthio)-9H-carbazol-3-yl]-, 1-(o-acetoxime) (product name "TR-PBG-314", manufactured by Changzhou Tronly New Electronic Materials Co., Ltd.), and 2-(acetoxyimino)-1-(6-(2-(acetoxyimino)-3-cyclohexylpropionyl)-9-ethylcarbazol-3-yl)-n-octane-1-one. Examples of commercially available products include TR-PBG-304, TR-PBG-314, and TR-PBG-345 (all manufactured by Changzhou Tronly New Electronic Materials Co., Ltd.).

[0080] Examples of oxime ester photopolymerization initiators having a phenyl sulfide structure include 1-[4-(phenylthio)phenyl]-3-cyclopentylpropane-1,2-dione-2-(o-benzoyloxime) (product name "TR-PBG-305", manufactured by Changzhou Tronly New Electronic Materials Co., Ltd.). Commercially available products include TR-PBG-305 and TR-PBG-3057 (both manufactured by Changzhou Tronly New Electronic Materials Co., Ltd.).

[0081] Examples of oxime ester-based photopolymerization initiators having a fluorene structure include [(Z)-[3-cyclohexyl-1-(9,9-dibutyl-7-nitrofluoren-2-yl)propylidene]amino)acetate. Commercially available products include TR-PBG-358 (manufactured by Changzhou Tronly New Electronic Materials Co., Ltd.).

[0082] The oxime ester photopolymerization initiator may be a compound that does not have a carbazole structure, a phenyl sulfide structure, or a fluorene structure. Examples of such oxime ester photopolymerization initiators include 1-phenyl-1,2-propanedione-2-o-benzoyl oxime.

[0083] The content of the oxime ester photopolymerization initiator is 0.3 mass parts or more relative to the total of 100 mass parts of the components (A) and (B). Thus, even in any of the mask exposure method and the direct drawing method, when forming a resist pattern, the deviation from the design value of the resist line width obtained can be reduced. From the viewpoint of further improving the above-mentioned effect, the content of the oxime ester photopolymerization initiator can be 0.35 mass parts or more or 0.4 mass parts relative to the total of 100 mass parts of the components (A) and (B). Furthermore, from the viewpoint of obtaining appropriate sensitivity, the content of the oxime ester photopolymerization initiator can be 3.0 mass parts or less, 2.5 mass parts or less or 2.0 mass parts or less relative to the total of 100 mass parts of the components (A) and (B). From these viewpoints, the content of the oxime ester photopolymerization initiator may be 0.3 to 3.0 parts by mass, 0.35 to 2.5 parts by mass, or 0.4 to 2.0 parts by mass relative to 100 parts by mass of the total of the components (A) and (B).

[0084] From the viewpoint of obtaining appropriate sensitivity, the content of the oxime ester photopolymerization initiator can be within the following ranges based on the total mass of the (C) component. The content of the oxime ester photopolymerization initiator can be 50% by mass or more, 60% by mass or more, 65% by mass or more, 70% by mass or more, or 75% by mass or more. The content of the oxime ester photopolymerization initiator can be 100% by mass. That is, the (C) photopolymerization initiator can be composed solely of the oxime ester photopolymerization initiator. From these viewpoints, the above content can be 50-100% by mass, 60-100% by mass, 65-100% by mass, 70-100% by mass, or 75-100% by mass.

[0085] The photosensitive resin composition according to this embodiment may further contain a photopolymerization initiator other than the oxime ester photopolymerization initiator. Examples of other photopolymerization initiators include hexaarylbisimidazole derivatives. From the perspective of further improving sensitivity and adhesion, the photopolymerization initiator is preferably at least one 2,4,5-triaryl imidazole dimer. The structure of the 2,4,5-triaryl imidazole dimer may be symmetrical or asymmetrical.

[0086] Examples of the 2,4,5-triaryl imidazole dimer include 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer (also known as 2,2'-bis(o-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole), 2-(o-chlorophenyl)-4,5-bis-(m-methoxyphenyl)imidazole dimer, and 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer. Among these, 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer is preferred.

[0087] Examples of other photopolymerization initiators include diphenyl ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone, 1,2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholino)phenyl]-1-butanone, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propanone, 1 and the like; quinones such as alkyl anthraquinone; benzoin ether compounds such as benzoin alkyl ether; benzoin compounds such as benzoin and alkyl benzoin; benzyl derivatives such as benzyl dimethyl ketal; bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; bis(2,6-dimethylbenzoyl)-2,4,4-trimethyl-pentylphosphine oxide; (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide, etc.

[0088] When the photosensitive resin composition according to the present embodiment contains the above-mentioned other photopolymerization initiator, the content of the photopolymerization initiator may be 0.01 to 10 parts by mass, 0.01 to 8 parts by mass, or 0.01 to 5 parts by mass relative to 100 parts by mass of the total of the components (A) and (B).

[0089] From the perspective of further improving sensitivity and adhesion, the content of component (C) can be within the following ranges based on the total solid content (total mass) of the photosensitive resin composition. The content of component (C) can be 0.1% by mass or more, 0.2% by mass or more, 0.3% by mass or more, or 0.35% by mass or more. The content of component (C) can be 20% by mass or less, 10% by mass or less, 3% by mass or less, 1% by mass or less, 0.5% by mass or less, or 0.4% by mass or less. From these perspectives, the content of component (C) can be 0.1 to 20% by mass, 0.1 to 10% by mass, or 0.1 to 3% by mass.

[0090] ((D) component: hydrogen donor)

[0091] The photosensitive resin composition according to this embodiment may further contain a hydrogen donor capable of donating hydrogen during the reaction of the exposed portion, thereby further improving the sensitivity of the photosensitive resin composition.

[0092] Examples of the component (D) include bis[4-(dimethylamino)phenyl]methane, bis[4-(diethylamino)phenyl]methane, colorless crystal violet, and N-phenylglycine. The component (D) can be used alone or in any combination of two or more.

[0093] When the photosensitive resin composition involved in the present embodiment contains component (D), the content of component (D) can be within the following range relative to 100 parts by mass of the total amount of component (A) and component (B). From the viewpoint of further improving sensitivity, the content of component (D) can be 0.01 parts by mass or more, 0.05 parts by mass or more, 0.1 parts by mass or more, 0.3 parts by mass or more, 0.5 parts by mass or more, or 0.6 parts by mass or more. From the viewpoint of suppressing the precipitation of excess component (D) as foreign matter after film formation, the content of component (D) can be 10 parts by mass or less, 5 parts by mass or less, 2 parts by mass or less, or 1 part by mass or less. From these viewpoints, the content of component (D) can be 0.01 to 10 parts by mass, 0.05 to 5 parts by mass, or 0.1 to 2 parts by mass.

[0094] (Sensitizing pigment)

[0095] The photosensitive resin composition according to this embodiment may further contain a sensitizing dye. This further improves the sensitivity of the photosensitive resin composition. Examples of sensitizing dyes include dialkylaminobenzophenones, pyrazolines, anthracenes, coumarins, xanthones, oxazoles, benzoxazoles, thiazoles, benzothiazoles, triazoles, stilbenes, triazines, thiophenes, naphthalimides, and triarylamines. These sensitizing dyes may be used alone or in any combination of two or more.

[0096] In particular, when the photosensitive resin layer is exposed using active light having a wavelength of 390 to 420 nm, from the viewpoint of further improving sensitivity and adhesion, the sensitizing dye may include at least one selected from the group consisting of pyrazolines, anthracenes, coumarins, and triarylamines, and may also include at least one selected from the group consisting of pyrazolines, anthracene derivatives, and triarylamines.

[0097] When the photosensitive resin composition according to this embodiment contains a sensitizing dye, the content of the sensitizing dye can be 0.01 to 10 parts by mass, 0.05 to 5 parts by mass, or 0.1 to 3 parts by mass relative to 100 parts by mass of the total amount of component (A) and component (B). When the sensitizing dye content is 0.01 parts by mass or greater, sensitivity and resolution are further improved. When the sensitizing dye content is 10 parts by mass or less, the resist shape is further suppressed from becoming an inverted trapezoidal shape, further improving adhesion.

[0098] (Other ingredients)

[0099] The photosensitive resin composition involved in the present embodiment can also contain other ingredients as needed in addition to the above-mentioned components. As other ingredients, for example, dyes (malachite green, etc.), tribromophenyl sulfone, light coloring agent, heat color blocking agent, plasticizer (p-toluene sulfonamide, etc.), pigments, fillers, defoamers, flame retardants, stabilizers, adhesion imparting agents, leveling agents, peeling accelerators, antioxidants, fragrances, developers and thermal crosslinking agents can be cited. These can be used alone or in any combination of two or more.

[0100] The content of each of these components is preferably about 0.01 to 20 parts by mass based on 100 parts by mass of the total amount of the component (A) and the component (B).

[0101] The content of coloring matter such as dye and pigment may be less than 0.5% by mass, or may be 0.45% by mass or less, based on the solid content (total mass) of the photosensitive resin composition.

[0102] The photosensitive resin composition of this embodiment may contain at least one organic solvent as needed to adjust the viscosity. Commonly used organic solvents can be used without particular limitation. Examples of organic solvents include methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N,N-dimethylformamide, propylene glycol monomethyl ether, and mixed solvents thereof.

[0103] The photosensitive resin composition according to the present embodiment can be used as a solution (hereinafter referred to as a "coating solution") having a solid content of about 30 to 60% by mass by dissolving at least the components (A), (B), and (C) in the above-mentioned organic solvent.

[0104] The coating liquid can be used, for example, to form a photosensitive resin layer as follows. By applying the coating liquid to the surface of a support (support film, metal plate, etc.) described below and drying it, a photosensitive resin layer derived from the photosensitive resin composition can be formed on the support. Examples of the metal plate include copper, copper alloys, nickel, chromium, iron, and iron alloys (such as stainless steel), with copper, copper alloys, and iron alloys being preferred.

[0105] The thickness of the photosensitive resin layer varies depending on its application, but can be approximately 1 to 100 μm in thickness after drying.

[0106] The photosensitive resin composition according to the present embodiment can be preferably used in, for example, a method for forming a resist pattern described below. Among them, it is preferably used in a method for forming a conductive pattern (circuit) by plating.

[0107] <Photosensitive element>

[0108] The photosensitive element involved in this embodiment includes a support and a photosensitive resin layer arranged on the support. The above-mentioned photosensitive resin layer contains the photosensitive resin composition involved in this embodiment or its cured product. In addition, the above-mentioned photosensitive resin layer is formed using the photosensitive resin composition involved in this embodiment, and the above-mentioned photosensitive resin composition can be in an uncured state (coating film). The above-mentioned photosensitive element can have other layers such as a protective layer as needed. For example, the surface (surface) on the side opposite to the surface of the support of the photosensitive resin layer can be coated with a protective layer (protective film, etc.).

[0109] Figure 1 An embodiment of a photosensitive element is shown. Figure 1 In the photosensitive element 1 shown, a support 2, a photosensitive resin layer 3, and a protective layer 4 are stacked in this order. The photosensitive element 1 can be obtained, for example, by applying a coating liquid, which is a photosensitive resin composition, onto the support 2 to form a coating layer, and then drying the coating layer to form the photosensitive resin layer 3. Subsequently, the surface of the photosensitive resin layer 3 opposite to the support 2 is coated with the protective layer 4. This yields a photosensitive element 1 comprising the support 2, the photosensitive resin layer 3 formed on the support 2, and the protective layer 4 stacked on the photosensitive resin layer 3. The photosensitive element 1 does not necessarily need to include the protective layer 4.

[0110] As the support, a heat-resistant and solvent-resistant polymer film such as a polyethylene terephthalate film, a polyethylene film, a polypropylene film, or a polyester film can be used.

[0111] The thickness of the support (support film, etc.) can be 1 to 100 μm, 5 to 50 μm, or 5 to 30 μm. A support thickness of 1 μm or greater can easily prevent damage to the support during peeling. A support thickness of 100 μm or less can easily prevent a decrease in resolution when exposure is performed through the support.

[0112] The protective layer (protective film, etc.) is preferably one with a lower bond force to the photosensitive resin layer than the bond force of the support to the photosensitive resin layer, and preferably a film with low fisheyes. "Fisheyes" refers to foreign matter, unmelted matter, oxidative degradation products, etc., which are absorbed into the film when the material constituting the protective film is heat-melted and then manufactured through kneading, extrusion, biaxial stretching, casting, etc. In other words, "low fisheyes" means that the film contains few of these foreign matter.

[0113] Specifically, heat-resistant and solvent-resistant polymer films such as polyethylene terephthalate film, polyethylene film, polypropylene film, and polyester film can be used as the protective layer. Examples of commercially available polymer films include polypropylene films manufactured by Oji Paper Co., Ltd. (e.g., ALPHAUN MA-410 and E-200C) and Shin-Etsu Film Co., Ltd.; and polyethylene terephthalate films such as PS-25 (e.g., PS series) manufactured by Teijin Limited. The protective layer may be of the same or different type as the support.

[0114] The thickness of the protective layer can be 1 to 100 μm, 5 to 50 μm, 5 to 30 μm, or 15 to 30 μm. A protective layer thickness of 1 μm or greater can prevent cracking of the protective layer when the photosensitive resin layer and support layer are laminated onto a substrate (such as a base plate) while the protective layer is being peeled off. A protective layer thickness of 100 μm or less improves productivity.

[0115] The photosensitive element of this embodiment can be manufactured, for example, as follows. The photosensitive element can be manufactured by a manufacturing method comprising the following steps: dissolving at least component (A), component (B), and component (C) in an organic solvent to prepare a coating solution having a solid content of approximately 30 to 60% by mass; applying the coating solution onto a support to form a coating layer; and drying the coating layer to form a photosensitive resin layer.

[0116] The coating liquid can be applied to the support by known methods such as roll coating, comma coating, gravure coating, air knife coating, die coating, and rod coating. Drying of the coating layer is not particularly limited as long as at least a portion of the organic solvent can be removed from the coating layer. For example, drying can be performed at 70 to 150°C for approximately 5 to 30 minutes. To prevent diffusion of the organic solvent in subsequent steps, the amount of residual organic solvent in the photosensitive resin layer after drying may be 2% by mass or less.

[0117] The thickness of the photosensitive resin layer in the photosensitive element of this embodiment can be appropriately selected depending on the intended use, but may be 1 to 100 μm, 1 to 50 μm, or 5 to 40 μm after drying. A photosensitive resin layer thickness of 1 μm or greater facilitates industrial coating and improves productivity. A photosensitive resin layer thickness of 100 μm or less further improves adhesion and resolution.

[0118] The photosensitive element according to this embodiment may further include a buffer layer, an adhesive layer, a light absorbing layer, a gas barrier layer, or other known intermediate layers, as needed.

[0119] The form of the photosensitive element according to the present embodiment is not particularly limited. The photosensitive element may be in a sheet form or in a roll form wound around a core, for example.

[0120] The photosensitive element according to this embodiment can be preferably used in, for example, a method for forming a resist pattern described below. Among them, it is suitable for use in a method for forming a conductor pattern (circuit) by plating.

[0121] <Method for Forming a Resist Pattern>

[0122] The method for forming a resist pattern according to the present embodiment includes: (i) a step of forming a photosensitive resin layer on a substrate (such as a base plate) using the above-mentioned photosensitive resin composition or the above-mentioned photosensitive element (photosensitive resin layer forming step); (ii) a step of irradiating at least a portion of the above-mentioned photosensitive resin layer with active light to cure the above-mentioned photosensitive resin layer (exposure step); and (iii) a step of removing the uncured portion of the above-mentioned photosensitive resin layer from the above-mentioned substrate to form a resist pattern (development step), and other steps may be included as needed. In addition, the resist pattern is also called a relief pattern. The method for forming a resist pattern according to the present embodiment is also called a method for manufacturing a substrate with a resist pattern.

[0123] ((i) Photosensitive Resin Layer Formation Step)

[0124] In the photosensitive resin layer forming step, a photosensitive resin layer is formed on a substrate (such as a base plate) using the photosensitive resin composition or the photosensitive element. The substrate is not particularly limited, but examples thereof include substrates having a conductive layer. As the substrate having a conductive layer, a circuit forming substrate or a die pad (a lead frame substrate, an alloy substrate, etc.) having an insulating layer and a conductive layer formed on the insulating layer can be used.

[0125] As a method for forming a photosensitive resin layer on a substrate (such as a base plate), for example, after removing the protective layer from the photosensitive element, the photosensitive resin layer of the photosensitive element is heated and pressure-bonded to the substrate. This method can produce a laminate composed of a substrate, a photosensitive resin layer, and a support, in which these are sequentially laminated. Alternatively, the photosensitive resin layer can be formed by applying and drying the photosensitive resin composition.

[0126] From the viewpoint of further improving adhesion and followability, the photosensitive resin layer forming step is preferably carried out under reduced pressure. The heating of the photosensitive resin layer and / or the base material (substrate, etc.) during the pressure bonding can be carried out at a temperature of 70 to 130°C. The pressure of the pressure bonding can be around 0.1 to 1.0 MPa (1 to 10 kgf / cm 2These conditions can be appropriately selected as needed. Furthermore, if the photosensitive resin layer is heated to 70-130°C, preheating of the substrate is not necessary. However, preheating of the substrate may be performed to further improve adhesion and conformability.

[0127] (ii) Exposure process

[0128] In the exposure step, at least a portion of the photosensitive resin layer formed on a base material (substrate, etc.) is irradiated with active light, and the portion irradiated with the active light is cured to form a latent image.

[0129] In this case, if the support on the photosensitive resin layer is translucent to the active light, the active light can be irradiated through the support. If the support is light-shielding, the photosensitive resin layer can be irradiated with active light after removing the support.

[0130] As the exposure method, a method of irradiating active light in an image form by a direct drawing exposure method such as LDI (Laser Direct Imaging) exposure method or DLP (Digital Light Processing) exposure method can be used, or a method of irradiating active light in an image form through a negative or positive mask pattern called an artwork (mask exposure method) can be used, or these can be used in combination.

[0131] As the light source of the active light, 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 (argon laser, etc.), a solid laser (YAG laser, etc.), a semiconductor laser, etc. that effectively radiates ultraviolet light or visible light can be used. As the main wavelength of the active light, 355nm, 405nm, etc. can be mentioned. The main wavelength refers to the wavelength of the active light, for example, light with a main wavelength of 355nm can include light with a wavelength of 352 to 358nm.

[0132] ((iii) Development Step)

[0133] In the development step, the uncured portions of the photosensitive resin layer are removed from a substrate (such as a base plate), thereby forming a resist pattern composed of a cured product of the photosensitive resin layer. If a support is present on the photosensitive resin layer, the support is removed, and then the unexposed portions other than the exposed portions are removed (development). Development methods include wet development and dry development, with wet development being the most widely used.

[0134] When wet development is used, a developer corresponding to the photosensitive resin composition can be used and development can be performed by a known development method. Examples of development methods include dipping, stirring, spraying, brushing, patting, scraping, and shaking dipping. From the perspective of further improving resolution, a high-pressure spray method is most suitable. Development can be performed by combining two or more of these methods.

[0135] The structure of a developer can be appropriately selected according to the structure of the said photosensitive resin composition. As a developer, an alkaline aqueous solution and an organic solvent developer are mentioned, for example.

[0136] When used as a developer, alkaline aqueous solutions are safe, stable, and easy to work with. Examples of the salt base of the alkaline aqueous solution include alkali hydroxides such as lithium, sodium, or potassium hydroxides; alkali carbonates such as lithium, sodium, potassium, or ammonium carbonates or bicarbonates; alkali metal phosphates such as potassium phosphate and sodium phosphate; alkali metal pyrrolates such as sodium pyrrolate and potassium pyrrolate; borax; sodium metasilicate; tetramethylammonium hydroxide; ethanolamine; ethylenediamine; diethylenetriamine; 2-amino-2-hydroxymethyl-1,3-propanediol; 1,3-diamino-2-propanol; and morpholine.

[0137] Preferred alkaline aqueous solutions include a diluted solution of 0.1-5% by mass sodium carbonate, a diluted solution of 0.1-5% by mass potassium carbonate, a diluted solution of 0.1-5% by mass sodium hydroxide, and a diluted solution of 0.1-5% by mass sodium borate. The pH of the alkaline aqueous solution is preferably 9-11. The temperature of the alkaline aqueous solution is adjusted according to the alkali developability of the photosensitive resin layer. The alkaline aqueous solution may also contain a surfactant, a defoaming agent, or a small amount of an organic solvent to promote development.

[0138] Examples of the organic solvent include acetone, ethyl acetate, alkoxyethanols having an alkoxy group having 1 to 4 carbon atoms, ethanol, isopropyl alcohol, butanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether. One organic solvent may be used alone or in any combination of two or more. The content of the organic solvent in the aqueous developer is generally 2 to 90% by mass, and the temperature can be adjusted according to the alkali developability.

[0139] Examples of organic solvent developers include 1,1,1-trichloroethane, N-methylpyrrolidone, N,N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, and γ-butyrolactone. To prevent ignition, water is preferably added to the organic solvent in an amount of 1 to 20% by mass.

[0140] In this embodiment, after the unexposed portion is removed in the development step, the exposed portion may be heated at about 60 to 250° C. or at 0.2 to 10 J / cm 2The resist pattern is further cured by exposure of about 100 nm.

[0141] <Printed Wiring Board Manufacturing Method>

[0142] The method for manufacturing a printed wiring board according to this embodiment includes the following steps: forming a resist pattern on a substrate (such as a base plate) using the resist pattern forming method described above; and plating or etching the substrate (such as a base plate) and a component having the resist pattern (a base plate having a resist pattern formed thereon, a base plate with a resist pattern attached thereto) to form a conductive pattern. Furthermore, the method for manufacturing a printed wiring board according to this embodiment may include other steps, such as removing the resist pattern, as needed.

[0143] In this embodiment, for example, a resist pattern formed on a base material (substrate, etc.) can be used as a mask to perform plating or etching on the base material (for example, a conductor layer provided on the base material).

[0144] The plating method used in the method for manufacturing a printed wiring board may be either electrolytic plating or electroless plating, or both, with electroless plating being preferred. Examples of electroless plating include copper plating such as copper sulfate plating and copper pyrrolidone plating; solder plating such as high-speed solder plating; Watt bath (nickel sulfate-nickel chloride) plating; nickel plating such as nickel sulfanilate; and gold plating.

[0145] In the process of removing the resist pattern, for example, the resist pattern can be stripped using an aqueous solution that is more alkaline than the alkaline aqueous solution used in the above-mentioned development process. Examples of such strongly alkaline aqueous solutions include 1-10% by mass sodium hydroxide aqueous solutions and 1-10% by mass potassium hydroxide aqueous solutions. Examples of methods for removing the resist pattern include immersion and spraying, which can be used alone or in combination.

[0146] The method of etching treatment can be appropriately selected according to the conductor layer (metal layer) to be removed. As etching solution, for example, cupric chloride solution, ferric chloride solution, alkaline etching solution, and hydrogen peroxide etching solution can be mentioned. Among these, ferric chloride solution is preferably used from the viewpoint of good etching factor.

[0147] The printed wiring board manufactured by the method for manufacturing a printed wiring board according to this embodiment may be a multilayer printed wiring board and may have small-diameter through-holes.

[0148] The printed wiring board according to the present embodiment can be manufactured by a manufacturing method including the following steps: performing an etching process on a substrate having a resist pattern formed thereon by the resist pattern forming method according to the present embodiment or performing an etching process to form a conductor pattern. Figure 2An example of a production process of a printed wiring board by a semi-additive process will be described.

[0149] exist Figure 2 In (a), a substrate (circuit forming substrate) is prepared in which a conductor layer 10 is formed on an insulating layer 15. The conductor layer 10 is, for example, a metal copper layer. Figure 2 In (b), the photosensitive resin layer 32 is formed on the conductive layer 10 of the substrate through the above-mentioned photosensitive resin layer forming step. Figure 2 In (c), a mask 20 is placed on the photosensitive resin layer 32 and irradiated with active light 50, and the area other than the area where the mask 20 is placed is exposed to form a photocured portion. Figure 2 In (d), the region other than the photocured portion formed by the exposure step is removed from the substrate by a development step, thereby forming a resist pattern 30 as the photocured portion on the substrate. Figure 2 In (e), a plating layer 42 is formed on the conductor layer 10 by plating using the resist pattern 30 as a photocured portion as a mask. Figure 2 In (f), after the resist pattern 30 as the photocured portion is stripped off by an aqueous solution of a strong alkali, a portion of the plating layer 42 and the conductor layer 10 covered by the resist pattern 30 are removed by flash etching to form the conductor pattern 40. The conductor layer 10 and the plating layer 42 may be made of the same material or different materials. In the case where the conductor layer 10 and the plating layer 42 are made of the same material, the conductor layer 10 and the plating layer 42 may be integrated. In addition, in Figure 2 In the above description, the method of forming the resist pattern 30 using the mask 20 is described. However, the resist pattern 30 may be formed by a direct writing exposure method without using the mask 20 .

[0150] Example

[0151] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0152] [Examples 1 to 7 and Comparative Examples 1 to 6]

[0153] <Preparation of Photosensitive Resin Composition>

[0154] The materials listed in Tables 1 and 2 were mixed in the amounts (unit: parts by mass) shown in Tables 1 and 2 to prepare solutions of photosensitive resin compositions. The amounts (parts by mass) of the components other than the solvent shown in Tables 1 and 2 are expressed as the mass of the non-volatile components (solids content). Details of the components listed in Tables 1 and 2 are as follows.

[0155] ((A) Binder Polymer)

[0156] A-1: A solution of a copolymer of methacrylic acid / styrene / benzyl methacrylate / 2-hydroxyethyl methacrylate (mass ratio: 27 / 50 / 20 / 3, Mw: 35,000, acid value: 176.1 mgKOH / g, Tg: 106.8°C) in propylene glycol monomethyl ether / toluene (mass ratio 3 / 4) (solid content: 49.6% by mass)

[0157] A-2: A solution of a copolymer of methacrylic acid / methyl methacrylate / styrene / benzyl methacrylate (mass ratio: 27 / 5 / 45 / 23, Mw: 51,000, acid value: 176.1 mgKOH / g, Tg: 107.0°C) in propylene glycol monomethyl ether / toluene (mass ratio: 3 / 4) (solid content: 47% by mass)

[0158] ((B) Photopolymerizable compound)

[0159] FA-321M: 2,2-bis(4-(methacryloyloxypentaethoxy)phenyl)propane (manufactured by Resonac Holdings Corporation, number of EO groups: 10 (average value))

[0160] BP-2EM: 2,2-bis(4-(methacryloyloxypolyethoxy)phenyl)propane (EO groups: 2.6 (total value), manufactured by KYOEISHA CHEMICAL Co., LTD.)

[0161] BPE-200: 2,2-bis(4-(methacryloyloxydiethoxy)phenyl)propane (manufactured by Shin-Nakamura Chemical Co., Ltd.)

[0162] FA-024M: Polyalkylene glycol dimethacrylate (manufactured by Resonac Holdings Corporation, number of EO groups: 12 (average value), number of PO groups: 6 (average value))

[0163] FA-023M: Polyalkylene glycol dimethacrylate (manufactured by Resonac Holdings Corporation, number of EO groups: 6 (average), number of PO groups: 12 (average))

[0164] FA-MECH: γ-chloro-β-hydroxypropyl-β'-methacryloyloxyethyl phthalate (manufactured by Resonac Holdings Corporation)

[0165] ((C) Photopolymerization initiator)

[0166] B-CIM: 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole (manufactured by Changzhou Tronly New Electronic Materials Co., Ltd.)

[0167] TR-PBG-304: Oxime ester-based photopolymerization initiator having a carbazoline structure represented by the following formula (1) (manufactured by Changzhou Tronly New Electronic Materials Co., Ltd.)

[0168]

[0169] TR-PBG-305: Oxime ester-based photopolymerization initiator having a phenyl sulfide structure represented by the following formula (2) (manufactured by Changzhou Tronly New Electronic Materials Co., Ltd.)

[0170]

[0171] TR-PBG-314: Oxime ester-based photopolymerization initiator having a carbazoline structure represented by the following formula (3) (manufactured by Changzhou Tronly New Electronic Materials Co., Ltd.)

[0172]

[0173] TR-PBG-345: Oxime ester-based photopolymerization initiator having a carbazoline structure represented by the following formula (4) (manufactured by Changzhou Tronly New Electronic Materials Co., Ltd.)

[0174]

[0175] TR-PBG-358: Oxime ester-based photopolymerization initiator having a fluorene structure represented by the following formula (5) (manufactured by Changzhou Tronly New Electronic Materials Co., Ltd.)

[0176]

[0177] TR-PBG-365: Fluorine-containing oxime ester-based photopolymerization initiator (manufactured by Changzhou Tronly New Electronic Materials Co., Ltd.)

[0178] TR-PBG-3057: Oxime ester-based photopolymerization initiator having a phenyl sulfide structure represented by the following formula (6) (manufactured by Changzhou Tronly New Electronic Materials Co., Ltd.)

[0179]

[0180] (Other ingredients)

[0181] DBA: 9,10-dibutoxyanthracene (manufactured by KAWASAKI KASEI CHEMICALS LTD.)

[0182] TBC: 4-tert-butylcatechol (manufactured by DIC Corporation) (polymerization inhibitor)

[0183] LCV: Leuco Crystal Violet (Yamada Chemical Co., Ltd.) (colorant)

[0184] MKG: Malachite Green (manufactured by OSAKA ORGANIC CHEMICAL INDUSTRY LTD.) (Dye)

[0185] LA-7RD: 4-Hydroxy-2,2,6,6-tetramethylpiperidinyl-N-oxyl (manufactured by ADEKA CORPORATION)

[0186] FA-711MM: 1,2,2,6,6-pentamethylpiperidin-4-yl methacrylate (manufactured by Resonac Holdings Corporation)

[0187] SF-808H: A mixture of carboxybenzotriazole, 5-amino-1H-tetrazole, and methoxypropanol (manufactured by SANWA KASEICORP)

[0188] <Production of Photosensitive Elements>

[0189] The photosensitive resin compositions obtained above were coated onto a 16μm-thick polyethylene terephthalate film ("FS-31" manufactured by TORAY INDUSTRIES, INC., serving as a support) to a uniform thickness. Subsequently, the films were dried in hot air convection dryers at 80°C and 120°C, forming a photosensitive resin layer with a thickness of 25μm after drying. A polyethylene film ("NF-15" manufactured by Tamapoly CO., LTD., serving as a protective layer) was laminated onto the photosensitive resin layer to produce photosensitive elements comprising a support, a photosensitive resin layer, and a protective layer laminated in this order.

[0190] <Production of Laminated Body>

[0191] A glass epoxy material, i.e., a copper-clad laminate (substrate, manufactured by Resonac Holdings Corporation, product name "MLC-E-67"), in which copper foil (thickness: 35 μm) was laminated on both sides was washed with water, pickled and washed with water in sequence, and then dried with an air flow. The copper-clad laminate was heated to 80°C. While peeling off the protective layer, the photosensitive elements obtained above were laminated so that the photosensitive resin layer was in contact with the copper surface. Thus, a laminate in which a copper-clad laminate, a photosensitive resin layer and a support were laminated in sequence was obtained. The obtained laminate was used as a test piece in the evaluation test of the accuracy of the resist line width shown below. In addition, for lamination, a hot roller at 110°C was used, with a pressing pressure of 0.4 MPa and a roller speed of 1.0 m / min.

[0192] <Determination of minimum development time>

[0193] The laminate was cut into squares (5 cm x 5 cm) and the support was peeled off to obtain test pieces. The unexposed photosensitive resin layer in the test piece was then spray-developed using a 1% by mass sodium carbonate aqueous solution at 30°C at a pressure of 0.18 MPa (nozzle: full cone, distance between the target and the nozzle tip: 6 cm). The minimum development time (MD) was the shortest time required for visual confirmation of removal of the unexposed photosensitive resin layer.

[0194] <Evaluation of Resist Line Width Accuracy (Mask Exposure Method)>

[0195] 41-segment stepped plates (manufactured by Resonac Holdings Corporation) and a photomask (a photomask with a line width of 10 μm removed) were placed on the support of the test piece. Using a parallel light exposure machine (manufactured by ORC MANUFACTURING CO., LTD., product name: EXM1201), ultraviolet rays were irradiated from vertically above the photomask surface with an energy such that the number of remaining segments of the 41-segment stepped plates became 15 segments. Thereafter, the support was peeled off, and spray development was performed for a time twice the minimum development time obtained by the above method to remove the unexposed portion. Thus, a resist pattern as a photocured material of a photosensitive resin composition was formed on the copper-clad laminate. The line width of the obtained resist pattern was measured at 3 locations, and the average value thereof was taken as the measured value of the line width (unit: μm), and the ratio (measured value / design value) of the measured value to the design value (10 μm) of the line width of the mask was calculated. As the accuracy of the resist line width, the value of the ratio (measured value / design value) is shown in Tables 1 and 2. The closer this value is to 1, the smaller the deviation of the obtained resist line width from the designed value.

[0196] [Table 1]

[0197]

[0198] [Table 2]

[0199]

[0200] (Examples 8 to 12 and Comparative Examples 7 to 10)

[0201] <Preparation of Photosensitive Resin Composition>

[0202] The materials listed in Table 3 were mixed in the amounts (unit: parts by mass) shown in Table 3 to prepare a solution of a photosensitive resin composition. The amounts (parts by mass) of the components other than the solvent shown in Table 3 are expressed as the mass of the non-volatile components (solids content). Details of the components listed in Table 3 are as follows. However, details of the components identical to those shown in Tables 1 and 2 are as described above.

[0203] ((A) Binder Polymer)

[0204] A-3: A solution of a copolymer of methacrylic acid / methyl methacrylate / styrene / benzyl methacrylate (mass ratio: 27 / 5 / 45 / 23, Mw: 47,000, acid value: 176.1 mgKOH / g, Tg: 107.0°C) in acetone / propylene glycol monomethyl ether (mass ratio 6 / 1) (solid content: 47% by mass)

[0205] ((C) Photopolymerization initiator)

[0206] C-1: Oxime ester-based photopolymerization initiator having a carbazoline structure represented by the following formula (7) (manufactured by Nippon Kayaku Co., Ltd.)

[0207]

[0208] <Production of Photosensitive Elements>

[0209] The photosensitive resin compositions obtained above were coated onto a 16μm-thick polyethylene terephthalate film ("FS-31" manufactured by TORAY INDUSTRIES, INC., serving as a support) to a uniform thickness. Subsequently, the films were dried in hot air convection dryers at 80°C and 120°C, forming a photosensitive resin layer with a thickness of 25μm after drying. A polyethylene film ("NF-15" manufactured by Tamapoly CO., LTD., serving as a protective layer) was laminated onto the photosensitive resin layer to produce photosensitive elements comprising a support, a photosensitive resin layer, and a protective layer laminated in this order.

[0210] <Production of Laminated Body>

[0211] A glass epoxy material, i.e., a copper-clad laminate (substrate, manufactured by Resonac Holdings Corporation, product name "MLC-E-679"), in which copper foil (thickness: 35 μm) was laminated on both sides, was washed with water, pickled with acid, and washed with water, and then dried with an air flow. The copper-clad laminate was heated to 80°C. While peeling off the protective layer, the photosensitive elements obtained above were laminated so that the photosensitive resin layer was in contact with the copper surface. Thus, a laminate in which a copper-clad laminate, a photosensitive resin layer, and a support were laminated in sequence was obtained. The obtained laminate was used as a test piece in the evaluation test of the accuracy of the resist line width shown below. In addition, for lamination, a hot roller at 110°C was used, with a pressing pressure of 0.4 MPa and a roller speed of 1.0 m / min.

[0212] <Evaluation of Resist Line Width Accuracy (Direct Writing Method)>

[0213] A 41-segment stepped plate (manufactured by Resonac Holdings Corporation) was placed on the support of the above-mentioned test piece. Then, an LDI exposure machine (main wavelength 405nm, manufactured by ADTEC Engineering Co., Ltd., product name "DE-1UH") was used to expose the 41-segment stepped plate with an energy of 15 segments. Then, the support was peeled off and spray development was performed for 2 times the minimum development time obtained by the above method to remove the unexposed portion. Thus, a resist pattern (design value of line width: 10μm) as a photocured material of a photosensitive resin composition was formed on the copper-clad laminate. The line width of the obtained resist pattern was measured at 3 locations, and its average value was used as the measured value of the line width (unit: μm), and the ratio (measured value / design value) of the measured value to the design value (10μm) of the line width of the mask was obtained. The value of this ratio (measured value / design value) is shown in Table 3 as the accuracy of the resist line width. The closer this value is to 1, the smaller the deviation of the obtained resist line width from the designed value.

[0214]

[0215] Explanation of symbols

[0216] 1- photosensitive element, 2- support, 3, 32- photosensitive resin layer, 4- protective layer, 10- conductor layer, 15- insulating layer, 20- mask, 30- resist pattern, 40- conductor pattern, 42- plating layer, 50- active light.

Claims

1. A photosensitive resin composition comprising (A) a binder polymer, (B) a photopolymerizable compound having at least one ethylenically unsaturated bond, and (C) a photopolymerization initiator. The (C) photopolymerization initiator comprises an oxime ester photopolymerization initiator, The content of the oxime ester photopolymerization initiator is 0.3 parts by mass or more relative to 100 parts by mass of the total of the (A) binder polymer and the (B) photopolymerizable compound.

2. The photosensitive resin composition according to claim 1, wherein The (A) binder polymer has a structural unit derived from (meth)acrylic acid and a structural unit derived from benzyl (meth)acrylate or a benzyl (meth)acrylate derivative.

3. The photosensitive resin composition according to claim 1, wherein The (C) photopolymerization initiator consists only of the oxime ester-based photopolymerization initiator.

4. The photosensitive resin composition according to claim 1, wherein The oxime ester-based photopolymerization initiator includes a compound having a carbazole structure.

5. The photosensitive resin composition according to claim 1, wherein The oxime ester-based photopolymerization initiator includes a compound having a phenyl sulfide structure. The photosensitive resin composition according to claim 1 , wherein The oxime ester-based photopolymerization initiator includes a compound having a fluorene structure.

7. The photosensitive resin composition according to claim 1, wherein The content of the oxime ester photopolymerization initiator is 3.0 parts by mass or less relative to 100 parts by mass of the total of the (A) binder polymer and the (B) photopolymerizable compound. The photosensitive resin composition according to claim 1 , which is used for a direct writing method.

9. A photosensitive element comprising a support and a photosensitive resin layer disposed on the support. The photosensitive resin layer comprises the photosensitive resin composition according to any one of claims 1 to 8 or a cured product thereof. 10 . A cured product, which is a cured product of the photosensitive resin composition according to claim 1 . The cured product according to claim 10 , which is a resist pattern.

12. A method for forming a resist pattern, comprising the following steps: Using the photosensitive resin composition according to any one of claims 1 to 8, forming a photosensitive resin layer on a substrate; irradiating at least a portion of the photosensitive resin layer with active light to cure the photosensitive resin layer; and An uncured portion of the photosensitive resin layer is removed from the substrate to form a resist pattern.

13. A method for forming a resist pattern, comprising the following steps: Using the photosensitive element according to claim 9, forming a photosensitive resin layer on a substrate; irradiating at least a portion of the photosensitive resin layer with active light to cure the photosensitive resin layer; and An uncured portion of the photosensitive resin layer is removed from the substrate to form a resist pattern.

14. A method for manufacturing a printed circuit board, comprising the following steps: forming a resist pattern on the substrate by the resist pattern forming method according to claim 12; and The substrate and the member having the resist pattern are subjected to plating or etching.

15. A method for manufacturing a printed circuit board, comprising the following steps: forming a resist pattern on the substrate by the resist pattern forming method according to claim 13; and The substrate and the member having the resist pattern are subjected to plating or etching.

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