Alkali-soluble resin, photosensitive resin composition, photosensitive element, method for forming resist pattern, and method for forming wiring pattern

Abstract

Provided is an alkali-soluble resin containing a structural unit having a polarity conversion group and a structural unit having a carboxyl group, wherein the polarity conversion group has a group that is not eliminated under weakly alkaline conditions but is eliminated under strongly alkaline conditions.

Description

Technical Field

[0001] This invention relates to an alkali-soluble resin, a photosensitive resin composition, a photosensitive element, a method for forming a resist pattern, and a method for forming a wiring pattern. Background Technology

[0002] In the field of printed circuit board manufacturing, photosensitive resin compositions and photosensitive elements comprising a layer formed on a support film using the photosensitive resin composition (hereinafter also referred to as "photosensitive layer") are widely used as resist materials for etching or plating processes.

[0003] Printed circuit boards are manufactured through the following processes, for example, using photosensitive elements. Specifically, a photosensitive layer of the photosensitive element is laminated onto a circuit-forming substrate such as a copper-clad laminate. The photosensitive layer is exposed using a mask or similar means to form a photocurable portion. At this time, a support film is peeled off before or after exposure. Then, the area of ​​the photosensitive layer excluding the photocurable portion is removed using a developer to form a resist pattern. Using the resist pattern as a resist, etching or plating processes are performed to form a conductor pattern, and finally, the photocurable portion (resist pattern) of the photosensitive layer is peeled off (removed).

[0004] From an environmental impact perspective, aqueous stripping solutions have been used instead of conventional amine stripping solutions to strip resist patterns (e.g., see Patent Document 1).

[0005] Previous technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent 2013-061556A Summary of the Invention

[0008] The technical problem to be solved by the invention

[0009] The photosensitive resin composition not only needs to form a resist pattern with high developability and excellent resolution in the unexposed areas, but also needs to have excellent release properties in the photocured areas to peel off and remove the resist pattern. On the other hand, when using an aqueous release solution, the release time of the resist pattern is longer than that when using an amine release solution, and there is a tendency for the release sheet to not shrink. To improve the release properties, it is possible to increase the hydrophilicity of the binder resin contained in the photosensitive layer, but this will make the exposed areas of the photosensitive layer prone to swelling during development, resulting in a decrease in resolution. On the other hand, when attempting to increase the hydrophobicity of the binder resin, not only is the developability of the unexposed areas reduced, but it is also impossible to shorten the resist pattern release time and reduce the size of the release sheet.

[0010] The present invention aims to provide an alkali-soluble resin used in a photosensitive resin composition having excellent developability, resolution and peeling properties, a photosensitive element, a method for forming a resist pattern and a method for forming a wiring pattern.

[0011] means for solving technical problems

[0012] One aspect of the present invention relates to an alkali-soluble resin comprising structural units having polarity switching groups and structural units having carboxyl groups, wherein the polarity switching groups have groups that are not eliminated under weakly alkaline conditions but are eliminated under strongly alkaline conditions.

[0013] In another embodiment, the present invention relates to a photosensitive resin composition comprising an adhesive resin containing the above-mentioned alkali-soluble resin, a photopolymerizable compound, and a photopolymerization initiator.

[0014] In another embodiment, the present invention relates to a photosensitive element comprising a support and a photosensitive layer formed on the support, wherein the photosensitive layer comprises the photosensitive resin composition.

[0015] In another embodiment, the present invention provides a method for forming a resist pattern, comprising: forming a photosensitive layer on a substrate using a photosensitive resin composition or a photosensitive element; irradiating at least a portion of the photosensitive layer with active light to form a photocurable portion; and removing at least a portion of the photosensitive layer from the substrate, excluding the photocurable portion.

[0016] In another embodiment, the present invention relates to a method for forming a wiring pattern, comprising the step of forming a conductor pattern by etching or plating a substrate having a resist pattern formed thereon by a resist pattern forming method.

[0017] Invention Effects

[0018] The present invention provides an alkali-soluble resin for use in a photosensitive resin composition having excellent developability, resolution and peeling properties, a photosensitive element, a method for forming a resist pattern and a method for forming a wiring pattern. Attached Figure Description

[0019] Figure 1 This is a schematic cross-sectional view showing one embodiment of a photosensitive element. Detailed Implementation

[0020] The embodiments of the present invention will now be described in detail. However, the present invention is not limited to the following embodiments.

[0021] In this specification, the term "step" includes not only independent steps, but also steps that, while not clearly distinguishable from other steps, achieve the desired effect. Numerical ranges indicated by "~" include the ranges specified before and after the "~" as minimum and maximum values, respectively. The term "layer" includes not only structures forming a shape across the entire surface, but also structures forming a shape in a localized area when viewed from above. "(meth)acrylic acid" refers to at least one of its corresponding "acrylic acid" and "methacrylic acid." Similarly, the same applies to expressions such as (meth)acryloyl.

[0022] In this specification, when multiple substances corresponding to each component are present, unless otherwise specified, the amount of each component in the photosensitive resin composition refers to the total amount of the multiple substances present in the photosensitive resin composition. Within the numerical range described in this specification, the upper or lower limit of the numerical range can be replaced with the values ​​shown in the examples. Furthermore, any combination of the contents described in this specification is also included in this invention. In this specification, "solid" refers to non-volatile components other than water and solvents contained in the photosensitive resin composition. That is, "solid" refers to components other than solvents that do not volatilize and remain after the drying process of the photosensitive resin composition described later, and also includes components that are liquids, syrups, and waxes at room temperature (25°C).

[0023] [Alkali-soluble resin]

[0024] The alkali-soluble resin according to this embodiment comprises a structural unit having a polar conversion group and a structural unit having a carboxyl group, wherein the polar conversion group has a group that is not eliminated under weakly alkaline conditions but is eliminated under strongly alkaline conditions.

[0025] Alkali-soluble resins are resins that are soluble in alkaline aqueous solutions. Examples of alkaline aqueous solutions include aqueous solutions of tetramethylammonium hydroxide (TMAH), aqueous solutions of metal hydroxides, aqueous solutions of metal carbonates, and aqueous solutions of organic amines. Whether a resin is soluble in alkaline aqueous solutions can be confirmed, for example, as follows.

[0026] A varnish obtained by dissolving resin in any solvent is applied to a substrate such as a silicon wafer to form a coating film with a thickness of 5 μm. This film is then immersed in an aqueous solution of TMAH, an aqueous solution of metal hydroxide, an aqueous solution of metal carbonate, or an aqueous solution of organic amine at 20–25 °C. When the coating film dissolves uniformly, the resin can be considered soluble in alkaline aqueous solutions.

[0027] In this embodiment, a "polarity-converting group" refers to a functional group whose polarity changes from hydrophobic to hydrophilic. The polarity-converting group according to this embodiment is stable and hydrophobic under weakly alkaline conditions, but can decompose under strongly alkaline conditions to generate hydrophilic groups such as hydroxyl and carboxyl groups. Examples of weakly alkaline conditions include developing the photosensitive layer with an alkaline aqueous solution during the formation of the resist pattern described later. Examples of strongly alkaline conditions include stripping the formed resist pattern with an alkaline aqueous solution. That is, the polarity-converting group according to this embodiment exhibits stable hydrophobicity in the weakly alkaline aqueous solution used for developing the photosensitive layer, and can be decomposed by the strongly alkaline aqueous solution used for stripping the resist pattern to change its hydrophilic groups.

[0028] The alkali-soluble resin according to this embodiment can be used as a binder resin in a photosensitive resin composition, and can improve the developability, resolution, and peel properties of the photosensitive layer formed from the photosensitive resin composition. Furthermore, by using the alkali-soluble resin according to this embodiment in a thick-film photosensitive resin composition, peel properties can be improved while maintaining resolution.

[0029] From the viewpoint of peeling properties, alkali-soluble resins contain structural units with polar conversion groups. From the viewpoint of further improving peeling properties, the polar conversion group can be a group represented by the following formula (1).

[0030]

[0031] In equation (1), R 2 This indicates trimethylsilyl, triethylsilyl, tert-butyldimethylsilyl, or triphenylmethyl. The group represented by formula (1) can be eliminated by removing R under strongly basic conditions. 2 It is converted to "-OH".

[0032] From the viewpoint of achieving an excellent balance between resolution and stripping properties, the structural unit having the above-mentioned polarity conversion group can be based on the structural unit of a compound represented by the following formula (2).

[0033]

[0034] In equation (2), R 1 L represents a hydrogen atom or a methyl group. 1 R represents an alkylene group having 1 to 6 carbon atoms. 2 This indicates trimethylsilyl, triethylsilyl, tert-butyldimethylsilyl, or triphenylmethyl. From the perspective of improving alkali solubility, L... 1 Preferably, it is an alkylene group having 1 to 4 carbon atoms, more preferably an alkylene group having 1 to 3 carbon atoms, and even more preferably an alkylene group having 2 to 3 carbon atoms.

[0035] Examples of compounds represented by formula (2) include 2-(trimethylsiloxy)ethyl(meth)acrylate, trimethylsilyl(meth)acrylate and triphenyl(meth)acrylate.

[0036] For example, the alkali-soluble resin according to this embodiment can be manufactured by free radical polymerization of monomers having polarity conversion groups and monomers having carboxyl groups.

[0037] From the viewpoint of further improving peeling properties, the content of monomers with polar conversion groups can be 1% or more, 2% or more, 3% or more, or 4% or more, relative to the total amount of monomers constituting the alkali-soluble resin. From the viewpoint of further improving developability, the content of monomers with polar conversion groups can be 35% or less, 30% or less, or 25% or less.

[0038] From the perspective of alkaline developability, alkali-soluble resins contain structural units with carboxyl groups. Examples of monomers with carboxyl groups include (meth)acrylic acid, α-bromoacrylic acid, α-chloroacrylic acid, β-furanyl(meth)acrylic acid, β-styryl(meth)acrylic acid, maleic acid, maleic anhydride, monomethyl maleate, monoethyl maleate, maleic acid monoesters such as monoisopropyl maleate, fumaric acid, cinnamic acid, α-cyanocinonic acid, itaconic acid, crotonic acid, and propynic acid. From the perspective of further improving alkaline developability, monomers with carboxyl groups can be (meth)acrylic acid or methacrylic acid.

[0039] From the perspective of balancing alkali developability and alkali resistance, the content of structural units derived from carboxyl-containing monomers can be 10–45% by mass, 15–40% by mass, or 20–35% by mass relative to the total amount of monomers constituting the alkali-soluble resin. When the content is 10% by mass or more, alkali developability is easily improved, while when the content is 45% by mass or less, alkali resistance is easily excellent.

[0040] From the perspective of adhesion and peeling properties, alkali-soluble resins can have structural units based on styrene or styrene derivatives. Styrene derivatives are polymeric compounds, such as vinyltoluene and α-methylstyrene, in which the hydrogen atoms at the α-position or in the aromatic ring of styrene have been substituted. The content of styrene-based or styrene derivative structural units in the alkali-soluble resin can be 10–60% by mass, 15–55% by mass, or 25–50% by mass. When the content is 10% by mass or higher, adhesion is easily improved; when the content is 60% by mass or lower, it is easy to suppress the increase in the size of the release film during development and to suppress the increase in the peeling time.

[0041] From the perspective of resolution and aspect ratio, alkali-soluble resins can have structural units based on (meth)benzyl acrylate. From the perspective of improving resolution, the content of structural units derived from (meth)benzyl acrylate in the alkali-soluble resin can be 5–50% by mass, 15–45% by mass, or 10–40% by mass.

[0042] From the viewpoint of improving plasticity, alkali-soluble resins can have structural units based on alkyl (meth)acrylates. Examples of alkyl (meth)acrylates 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.

[0043] From the perspective of improving resolution, the weight-average molecular weight (Mw) of alkali-soluble resins can be 1000 or higher, 2000 or higher, 3000 or higher, or 5000 or higher. From the perspective of developability, the Mw of alkali-soluble resins can be 30000 or lower, 28000 or lower, 26000 or lower, or 24000 or lower. Mw can be determined, for example, by gel permeation chromatography (GPC) using a standard polystyrene calibration curve.

[0044] The degree of hydrophilicity of alkali-soluble resins can be calculated using the following formula, based on the hydrophilicity of the monomers constituting the alkali-soluble resin and the copolymerization ratio of the monomers. The hydrophilicity of the monomers refers to the water content (mass%) in the monomers after adding ion-exchanged water and placing them at 23°C for 12 hours, as determined by the Karl Fischer method. The hydrophilicity of the alkali-soluble resin = copolymerization ratio of monomers (mass%) × hydrophilicity of monomers.

[0045] From the viewpoint of alkali resistance of the exposure section during development, the hydrophilicity of the alkali-soluble resin before the polarity conversion group decomposes can be 80–120, 82–115, or 84–110. From the viewpoint of peeling properties, the hydrophilicity of the alkali-soluble resin after the polarity conversion group decomposes can be 95–120, 98–115, or 100–110. From the viewpoint of further improving the balance between developability, resolution, and peeling properties, the increase rate of hydrophilicity after polarity conversion can be 3–45%, 5–40%, or 10–35%.

[0046] [Photosensitive Resin Composition]

[0047] The photosensitive resin composition according to this embodiment comprises (A) an adhesive resin (hereinafter, sometimes referred to as "component (A)"); (B) a photopolymerizable compound (hereinafter, sometimes referred to as "component (B)"); and (C) a photopolymerization initiator (hereinafter, sometimes referred to as "component (C)"). Hereinafter, each component that may be contained in the photosensitive resin composition will be described in detail.

[0048] <(A) Adhesive Resin>

[0049] The adhesive resin as component (A) includes the alkali-soluble resin according to this embodiment (hereinafter, sometimes referred to as "component (A1)"). The inclusion of component (A1) improves the alkali resistance of the exposed portion during development and enables the formation of a resist pattern with excellent resolution. The resist pattern can be peeled off with a strongly alkaline aqueous solution. Component (A1) may consist of only one type of resin or may consist of two or more types of resin.

[0050] Component (A) may also contain alkali-soluble resins other than component (A1). Alkali-soluble resins may be resins containing phenolic hydroxyl groups. Examples of resins containing phenolic hydroxyl groups include polyhydroxystyrene, hydroxystyrene-based resins such as copolymers containing hydroxystyrene as monomer units, phenolic resins, polybenzoxazole precursors such as poly(hydroxyamide), poly(hydroxyphenylene) ether, and polynatrol.

[0051] Relative to the total amount of components (A) and (B) 100 parts by mass, the content of component (A) can be 30–90 parts by mass, 40–85 parts by mass, or 50–80 parts by mass. When the content of component (A) is within this range, the strength of the photocured portion of the photosensitive layer becomes better.

[0052] <(B) Photopolymerizable compounds>

[0053] Component (B) is a compound having a functional group, wherein the functional group comprises an olefinic unsaturated bond such as vinyl, allyl, propargyl, butenyl, ethynyl, phenylethynyl, maleimide, nadimide, and (meth)acryloyl as a polymerizable functional group. Component (B) is not particularly limited to being a compound having one or more olefinic unsaturated groups. As a polymerizable functional group, (meth)acryloyl is preferred. Component (B) can be used alone or in combination of two or more.

[0054] Examples of photopolymerizable compounds having one olefinic unsaturated group include (meth)acrylic acid, alkyl (meth)acrylates, and phthalic acid (meth)acrylate compounds.

[0055] Examples of alkyl methacrylates include methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and hydroxyethyl methacrylate.

[0056] From the viewpoint of appropriately improving resolution, adhesion, and resist shape, component (B) may contain phthalic acid compounds. Examples of phthalic acid compounds include γ-chloro-β-hydroxypropyl-β′-(meth)acryloyloxyethyl phthalate (also known as 3-chloro-2-hydroxypropyl-2-(meth)acryloyloxyethyl phthalate), β-hydroxyethyl-β′-(meth)acryloyloxyethyl phthalate, and β-hydroxypropyl-β′-(meth)acryloyloxyethyl phthalate.

[0057] Examples of photopolymerizable compounds having two olefinically unsaturated groups include polyethylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, polypropylene glycol di(meth)acrylate, 2,2-bis(4-(meth)acryloyloxypolyethoxypolypropoxyphenyl)propane, bisphenol A diglycidyl ether di(meth)acrylate, and epoxide-modified bisphenol A di(meth)acrylate.

[0058] From the viewpoint of improving alkaline developability and resolution, component (B) may contain epoxy-modified bisphenol A di(meth)acrylate. Examples of epoxy-modified bisphenol A di(meth)acrylate include 2,2-bis(4-((meth)acryloyloxypolyethoxy)phenyl)propane (e.g., 2,2-bis(4-((meth)acryloyloxypentethoxy)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.

[0059] Examples of photopolymerizable compounds having three or more olefinic unsaturated groups include (meth)acrylates having a backbone derived from trimethylolpropane, such as trimethylolpropane tri(meth)acrylate; (meth)acrylates having a backbone derived from tetramethylolmethane, such as tetramethylolmethane tri(meth)acrylate and tetramethylolmethane tetra(meth)acrylate; (meth)acrylates having a backbone derived from pentaerythritol, such as pentaerythritol tri(meth)acrylate and pentaerythritol tetra(meth)acrylate; (meth)acrylates having a backbone derived from dipentaerythritol, such as dipentaerythritol penta(meth)acrylate and dipentaerythritol hexa(meth)acrylate; (meth)acrylates having a backbone derived from dipentaerythritol, such as ditrimethylolpropane tetra(meth)acrylate; and (meth)acrylates having a backbone derived from diglycerol. Among these, from the viewpoint of enhancing chemical resistance after curing (exposure) and increasing the difference in developer resistance between exposed and unexposed areas, a (meth)acrylate compound having a backbone derived from dipentaerythritol is preferred, and a dipentaerythritol penta(meth)acrylate is more preferred.

[0060] From the viewpoint of improving the alkaline developability of the unexposed portion of the photosensitive resin composition and increasing the adhesion strength of the exposed portion, component (B) may contain a photopolymerizable compound having olefinic unsaturated groups and acid-modified groups. Examples of acid-modified groups include carboxyl, sulfonyl, and phenolic hydroxyl groups, among which carboxyl is preferred.

[0061] Examples of photopolymerizable compounds having olefinic unsaturated groups and acid groups include styrene-maleic acid resins and acid-modified epoxy derivatives containing vinyl groups.

[0062] Styrene-maleic acid resins are styrene-maleic anhydride copolymer products modified with (meth)acrylate. Vinyl-containing acid-modified epoxy derivatives are compounds obtained by reacting a compound having an epoxy resin modified with a vinyl-containing organic acid with a polycarboxylic anhydride containing saturated or unsaturated groups.

[0063] There are no particular limitations on epoxy resins as long as they are compounds having two or more epoxy groups. Examples of epoxy resins include glycidyl ether type epoxy resins, glycidyl amine type epoxy resins, and glycidyl ester type epoxy resins. Among these, from the viewpoint of reliability of semiconductor chip mounting, bisphenol phenolic varnish type epoxy resins are preferred, and bisphenol F phenolic varnish type epoxy resins are more preferred.

[0064] There is no particular limitation on the type of organic acid containing vinyl groups; it can be a vinyl monocarboxylic acid. Examples of vinyl monocarboxylic acids include acrylic acid, acrylic acid dimer, methacrylic acid, β-furfurylic acid, β-styrylic acid, cinnamic acid, crotonic acid, and α-cyanocinonic acid and other acrylic acid derivatives; half-ester compounds that are the reaction products of hydroxyl-containing acrylates and dicarboxylic anhydrides; and half-ester compounds that are the reaction products of vinyl monoglycidyl ethers or vinyl monoglycidyl esters and dicarboxylic anhydrides.

[0065] There are no particular restrictions on the olefinic unsaturated bond, as long as photopolymerization is possible. Examples of olefinic unsaturated bonds include α,β-unsaturated carbonyl groups, such as (meth)acryloyl groups. Examples of photopolymerizable compounds having α,β-unsaturated carbonyl groups include α,β-unsaturated carboxylic acid esters of polyols, bisphenol-type (meth)acrylates, α,β-unsaturated carboxylic acid adducts of compounds containing glycidyl groups, (meth)acrylates having urethane bonds, nonylphenoxy polyethyleneoxy acrylates, and alkyl (meth)acrylates.

[0066] Examples of α,β-unsaturated carboxylic acid esters of polyols include polyethylene glycol di(meth)acrylate having 2 to 14 vinyl groups, polypropylene glycol di(meth)acrylate having 2 to 14 propylene groups, polyethylene / polypropylene glycol di(meth)acrylate having 2 to 14 vinyl and 2 to 14 propylene 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, tetramethylolmethane tetra(meth)acrylate, and (meth)acrylate compounds having a backbone derived from dipentaerythritol or pentaerythritol. "EO-modified" indicates a block structure having ethylene oxide (EO) groups, and "PO-modified" indicates a block structure having propylene oxide (PO) groups.

[0067] From the viewpoint of improving the flexibility of the resist pattern, component (B) may contain polyalkylene glycol di(meth)acrylate. Polyalkylene glycol di(meth)acrylate may have at least one of an EO group and a PO group, or both. In polyalkylene glycol di(meth)acrylate having both EO and PO groups, each EO group and PO group may exist continuously in a block configuration or randomly. The PO group may be an oxypropenyl group or an oxyisopropenyl group. In the (poly)oxyisopropenyl group, the secondary carbon of the propenyl group may be bonded to an oxygen atom, or the primary carbon may be bonded to an oxygen atom.

[0068] Examples of commercially available polyalkylene glycol di(meth)acrylates include FA-023M (manufactured by Hitachi Chemical Co., Ltd.), FA-024M (manufactured by Hitachi Chemical Co., Ltd.), and NK ester HEMA-9P (manufactured by Shin-Nakamura Chemical Co., Ltd.).

[0069] From the viewpoint of improving the flexibility of the resist pattern, component (B) may contain (meth)acrylates having urethane bonds. Examples of (meth)acrylates having urethane bonds include addition products of (meth)acrylate monomers having an OH group at the β-position with diisocyanates (e.g., isophorone diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate and 1,6-hexamethylene diisocyanate), tri(meth)acryloyloxytetraethylene glycol isocyanate, hexamethylene isocyanate, EO-modified urethane di(meth)acrylate, and EO- and PO-modified urethane di(meth)acrylate.

[0070] Examples of commercially available EO-modified urethane di(meth)acrylate include “UA-11” and “UA-21EB” (manufactured by Shin-Nakamura Chemical Co., Ltd.). Examples of commercially available EO- and PO-modified urethane di(meth)acrylate include “UA-13” (manufactured by Shin-Nakamura Chemical Co., Ltd.).

[0071] From the viewpoint of easily forming a thicker resist pattern and uniformly improving resolution and adhesion, component (B) may contain a (meth)acrylate compound having a backbone derived from dipentaerythritol or pentaerythritol. The (meth)acrylate compound having a backbone derived from dipentaerythritol or pentaerythritol preferably has four or more (meth)acryloyl groups, and may be dipentaerythritol penta(meth)acrylate or dipentaerythritol hexa(meth)acrylate.

[0072] From the viewpoint of further improving the resolution and peel properties after curing, component (B) may contain bisphenol (meth)acrylate, and may contain bisphenol A (meth)acrylate, which belongs to the category of bisphenol (meth)acrylate. Examples of bisphenol A (meth)acrylate 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. Among these, from the viewpoint of further improving resolution and pattern forming ability, 2,2-bis(4-((meth)acryloyloxypolyethoxy)phenyl)propane is preferred.

[0073] Examples of commercially available 2,2-bis(4-((meth)acryloyloxydipropoxy)phenyl)propane include BPE-200 (Shin-Nakamura Chemical Co., Ltd.) and examples of 2,2-bis(4-(methacryloyloxypentethoxy)phenyl)propane include BPE-500 (Shin-Nakamura Chemical Co., Ltd.) and FA-321M (Hitachi Chemical Co., Ltd.).

[0074] Examples of nonylphenoxy polyethylene oxyacrylates include nonylphenoxy tetraethyleneoxyacrylate, nonylphenoxy pentaethyleneoxyacrylate, nonylphenoxy hexaethyleneoxyacrylate, nonylphenoxy heptaethyleneoxyacrylate, nonylphenoxy octaethyleneoxyacrylate, nonylphenoxy nonaethyleneoxyacrylate, nonylphenoxy decaethyleneoxyacrylate, and nonylphenoxy undecaethyleneoxyacrylate.

[0075] <(C) Photopolymerization Initiator>

[0076] There are no particular restrictions on component (C), as long as it is capable of polymerizing component (B), and it can be appropriately selected from conventional photopolymerization initiators. Component (C) can be used alone or in combination of two or more.

[0077] Examples of component (C) include photopolymerization initiators such as acylphosphine oxides, oxime esters, aromatic ketones, quinones, alkyl phenyl ketones, imidazoles, acridine, phenylglycine, and coumarins.

[0078] From the perspective of improving both sensitivity and resolution in a balanced way, component (C) may include acridine photopolymerization initiator, phenylglycine photopolymerization initiator or imidazole photopolymerization initiator.

[0079] Examples of acridine photopolymerization initiators include 9-phenylacridinium, 9-(p-methylphenyl)acridinium, 9-(m-methylphenyl)acridinium, 9-(p-chlorophenyl)acridinium, 9-(m-chlorophenyl)acridinium, 9-aminoacridinium, 9-dimethylaminoacridinium, 9-diethylaminoacridinium, 9-pentylaminoacridinium, bis(9-acridyl)alkanes such as 1,2-bis(9-acridyl)ethane, 1,4-bis(9-acridyl)butane, 1,6-bis(9-acridyl)hexane, 1,8-bis(9- (Acridine)octane, 1,10-bis(9-acridyl)decane, 1,12-bis(9-acridyl)dodecane, 1,14-bis(9-acridyl)tetradecane, 1,16-bis(9-acridyl)hexadecane, 1,18-bis(9-acridyl)octadecane and 1,20-bis(9-acridyl)eicosane, 1,3-bis(9-acridyl)-2-oxapropane, 1,3-bis(9-acridyl)-2-thiapropane and 1,5-bis(9-acridyl)-3-thiapentane.

[0080] Examples of phenylglycine photopolymerization initiators include N-phenylglycine, N-methyl-N-phenylglycine, and N-ethyl-N-phenylglycine.

[0081] Examples of imidazole photopolymerization initiators 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′-tetra-(3-methoxyphenyl)-biimidazole, 2,2′-bis-(2,3-difluoromethylphenyl)-4,4′,5,5′-tetra-(3-methoxyphenyl)-biimidazole, 2,2′-bis-(2,4-difluorophenyl)-4,4′,5,5′-tetra-(3-methoxyphenyl)-biimidazole and 2,2′-bis-(2,5-difluorophenyl)-4,4′,5,5′-tetra-(3-methoxyphenyl)-biimidazole.

[0082] Compared to the total amount of components (A) and (B) 100 parts by mass, the content of component (C) can be 0.1–10 parts by mass, 0.2–5 parts by mass, or 0.5–4 parts by mass. When the content of component (C) is 0.1 parts by mass or more, photosensitivity, resolution, and adhesion are easily improved; when the content is 10 parts by mass or less, the resist patterning ability is easily excellent.

[0083] <Ingredient (D): Photosensitizer>

[0084] The photosensitive resin composition according to this embodiment may further include a photosensitizer as component (D). By including component (D), the wavelength of the active light used for exposure can be effectively absorbed. Component (D) may be used alone or in combination of two or more.

[0085] Examples of component (D) include dialkylaminobenzophenone compounds, pyrazoline compounds, anthracene compounds, coumarin compounds, xanthonesone compounds, thioxanthonesone compounds, oxazole compounds, benzoxazole compounds, thiazole compounds, benzothiazole compounds, triazole compounds, stilbene compounds, triazine compounds, thiophene compounds, naphthimine compounds, triarylamine compounds, and aminoacridine compounds. From the viewpoint of further improving resolution, component (D) may contain pyrazoline compounds or anthracene compounds.

[0086] Examples of pyrazoline compounds include 1-(4-methoxyphenyl)-3-styryl-5-phenyl-pyrazoline, 1-phenyl-3-(4-methoxystyryl)-5-(4-methoxyphenyl)-pyrazoline, 1,5-bis-(4-methoxyphenyl)-3-(4-methoxystyryl)-pyrazoline, 1-(4-isopropylphenyl)-3-styryl-5-phenyl-pyrazoline, 1-phenyl-3-(4-isopropylstyryl)-5-(4-isopropylphenyl)-pyrazoline, 1,5-bis-(4-isopropylphenyl)-3-(4-isopropylstyryl)-pyrazoline, and 1-(4-methoxyphenyl)-3-(4-tert-butylstyryl)-5-(4-tert-butylphenyl)-pyrazoline. Phosphorus, 1-(4-tert-butylphenyl)-3-(4-methoxystyryl)-5-(4-methoxyphenyl)-pyrazoline, 1-(4-isopropylphenyl)-3-(4-tert-butylstyryl)-5-(4-tert-butylphenyl)-pyrazoline, 1-(4-tert-butylphenyl)-3-(4-isopropylstyryl)-5-(4-isopropylphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(4-isopropylstyryl)-5-(4-isopropylphenyl)-pyrazoline, 1-(4-isopropylphenyl)-3-(4-methoxystyryl)-5-(4-methoxyphenyl)-pyrazoline, 1-phenyl-3-(3,5-dimethoxystyryl)-5-(3,5- (2,6-Dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(3,4-dimethoxystyryl)-5-(3,4-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(2,6-dimethoxystyryl)-5-(2,6-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(2,5-dimethoxystyryl)-5-(2,5-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(2,4-dimethoxystyryl)-5-(2,4-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(3,5-dimethoxystyryl) -5-(3,5-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(3,4-dimethoxystyryl)-5-(3,4-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(2,6-dimethoxystyryl)-5-(2,6-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(2,5-dimethoxystyryl)-5-(2,5-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(2,4-dimethoxystyryl)-5-(2,5-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(2,4-dimethoxystyryl)-5-(2,4-Dimethoxyphenyl)-pyrazoline, 1-(4-tert-butylphenyl)-3-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butylphenyl)-3-(3,4-dimethoxystyryl)-5-(3,4-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butylphenyl)-3-(2,6-dimethoxystyryl)-5-(2,6-dimethoxyphenyl)-pyrazoline 1-(4-tert-butylphenyl)-3-(2,5-dimethoxystyryl)-5-(2,5-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butylphenyl)-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butylphenyl)-3-(2,4-dimethoxystyryl)-5-(2,4-dimethoxyphenyl)- Pyrazoline, 1-(4-isopropyl-phenyl)-3-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(3,4-dimethoxystyryl)-5-(3,4-dimethoxyphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(2,6-dimethoxystyryl)-5-(2,6-dimethoxyphenyl)-pyrazoline Phosphorus, 1-(4-isopropyl-phenyl)-3-(2,5-dimethoxystyryl)-5-(2,5-dimethoxyphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)-pyrazoline and 1-(4-isopropyl-phenyl)-3-(2,4-dimethoxystyryl)-5-(2,4-dimethoxyphenyl)-pyrazoline.

[0087] Examples of anthracene compounds include 9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, 9,10-dipropoxyanthracene, 9,10-dibutoxyanthracene and 9,10-dipentoxyanthracene.

[0088] From the perspective of improving photosensitivity and resolution, relative to the total amount of 100 parts by mass of components (A) and (B), the content of component (D) can be 0.01 to 5 parts by mass, 0.01 to 1 part by mass, or 0.01 to 0.2 parts by mass.

[0089] (Other ingredients)

[0090] The photosensitive resin composition according to this embodiment may further include additives as needed, such as dyes, photochromic agents, thermochromic inhibitors, plasticizers, pigments, fillers, defoamers, flame retardants, adhesion promoters, leveling agents, peel accelerators, antioxidants, fragrances, developers, thermal crosslinking agents, and polymerization inhibitors. These additives may be used alone or in combination of two or more.

[0091] Examples of dyes include peacock green, Victoria blue, brilliant green, and methyl violet. Examples of photochromic agents include tribromophenyl sulfone, colorless crystal violet, diphenylamine, benzylamine, triphenylamine, diethylaniline, and o-chloroaniline. Examples of plasticizers include p-toluenesulfonamide.

[0092] The photosensitive resin composition can be dissolved as needed in solvents such as methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N,N-dimethylformamide, propylene glycol monomethyl ether, or a mixture thereof to prepare a solution with a solid content of about 30 to 60% by mass.

[0093] [Image sensor]

[0094] The photosensitive element of this embodiment includes a support and a photosensitive layer formed on the support, the photosensitive layer comprising a photosensitive resin composition. When using the photosensitive element of this embodiment, the photosensitive layer is laminated onto a substrate, and exposure can then be performed without peeling off the support (support film). Figure 1 As shown in the schematic cross-sectional view of the embodiment, the photosensitive element 1 according to this embodiment is formed as follows: it includes a support 2 and a photosensitive layer 3 made of the above-described photosensitive resin composition formed on the support 2, and includes other layers such as a protective layer 4 provided as needed.

[0095] (Support structure)

[0096] Examples of supports include polyester films such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene 2,6-naphthalenedicarboxylate (PEN), and polyolefin films such as polypropylene and polyethylene. Among these, PET film is preferred from the viewpoint of its easy availability and excellent processability in the manufacturing process (especially its heat resistance, heat shrinkage, and tensile strength).

[0097] The haze of the support can be 0.01–1.0% or 0.01–0.5%. When the haze is above 0.01%, the support itself is easier to manufacture; when the haze is below 1.0%, fine defects that may occur in the resist pattern are more easily reduced. "Haze" refers to turbidity. In this invention, haze refers to the value measured using a commercially available turbidimeter according to the method specified in JIS K 7105. Haze can be measured using commercially available turbidimeters such as the NDH-5000 (manufactured by Nippon Denshoku Industries Co., Ltd.).

[0098] The thickness of the support can be 1–100 μm, 5–60 μm, 10–50 μm, 10–40 μm, 10–30 μm, or 10–25 μm. A thickness of 1 μm or more easily prevents support breakage during peeling. Conversely, a thickness of 100 μm or less suppresses resolution degradation during exposure with the support in between.

[0099] (protective layer)

[0100] The photosensitive element may further include a protective layer as needed. As a protective layer, a film with less adhesion between the photosensitive layer and the protective layer than between the photosensitive layer and the support can be used, or a film with fewer fisheyes can be used. Specific examples of the protective layer include those that can be used as the aforementioned support. From the viewpoint of peelability from the photosensitive layer, a polyethylene film can be used. Depending on the application, the thickness of the protective layer can be approximately 1 to 100 μm.

[0101] For example, a photosensitive element can be manufactured as follows: A photosensitive resin composition solution (coating liquid) is applied to a support to form a coating, and then dried to form a photosensitive layer. A protective layer is then used to cover the surface of the photosensitive layer on the side opposite to the support, thereby providing a photosensitive element comprising a support, a photosensitive layer formed on the support, and a protective layer laminated on the photosensitive layer.

[0102] The coating liquid can be applied to the support using known methods such as roller coating, comma coating, gravure coating, air knife coating, mold coating, and bar coating.

[0103] There are no particular restrictions on the drying of the coating, as long as at least some of the organic solvent can be removed from the coating. For example, drying can be carried out at 70–150°C for about 5–30 minutes. After drying, from the viewpoint of preventing the solvent from spreading in subsequent steps, the amount of solvent remaining in the photosensitive layer can be less than 2% by mass.

[0104] The thickness of the photosensitive layer in a photosensitive element can be appropriately selected according to the application; the thickness after drying can be 1–100 μm, 1–50 μm, or 5–40 μm. A thickness of 1 μm or more simplifies industrial coating and increases productivity. Furthermore, a thickness of less than 100 μm improves adhesion and resolution.

[0105] There are no particular limitations on the shape of the photosensitive element. For example, it can be in sheet form or rolled up in a core. When rolled up, it can be wound with the support film on the outside. Examples of cores include plastics such as polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, or ABS resin (acrylonitrile-butadiene-styrene copolymer).

[0106] From the perspective of end-face protection, end-face spacers can be provided on the end faces of the roll-shaped photosensitive element, and from the perspective of suppressing edge melting, moisture-proof end-face spacers can be provided. The photosensitive element can be covered with a black panel with low transparency.

[0107] Photosensitive elements can be suitably used, for example, in the methods for forming resist patterns described below. In particular, from the viewpoint of resolution, photosensitive elements are suitable for manufacturing methods that form conductor patterns by plating processes.

[0108] [Methods for forming resist patterns]

[0109] The method for forming a resist pattern according to this embodiment includes: (i) forming a photosensitive layer on a substrate using the above-described photosensitive resin composition or the above-described photosensitive element (photosensitive layer formation step); (ii) irradiating at least a portion (a predetermined portion) of the photosensitive layer with active light to form a photocurable portion (exposure step); and (iii) removing at least a portion other than the photocurable portion from the substrate to form a resist pattern (development step), and may include other steps as needed. The resist pattern may be referred to as a photocurable pattern of the photosensitive resin composition or an embossed pattern. The method for forming the resist pattern may be referred to as a method for manufacturing a substrate having a resist pattern.

[0110] (i) Photosensitive layer formation steps)

[0111] As a method for forming a photosensitive layer on a substrate, for example, the aforementioned photosensitive resin composition can be coated and dried, or after removing the protective layer from the photosensitive element, the photosensitive layer of the photosensitive element can be pressed onto the substrate while heating. Using a photosensitive element, a laminate in which a substrate, a photosensitive layer, and a support are sequentially stacked is provided. The substrate is not particularly limited; generally, a circuit forming substrate consisting of an insulating layer and a conductive layer formed on the insulating layer, or a chip pad (lead frame substrate) such as an alloy substrate, is used.

[0112] From the viewpoint of adhesion and tracking, when using a photosensitive element, the photosensitive layer formation step is preferably performed under reduced pressure. During the lamination process, the photosensitive layer and / or substrate can be heated at a temperature of 70–130°C. The lamination pressure can be approximately 0.1–1.0 MPa (approximately 1–10 kgf / cm²). 2 The process is carried out under pressure, but these conditions can be selected as needed. When the photosensitive layer is heated to 70-130°C, preheating of the substrate is not required, but preheating of the substrate can be performed to further improve adhesion and conformability.

[0113] (ii) Exposure steps)

[0114] In the exposure step, at least a portion of the photosensitive layer formed on the substrate is irradiated with active light, and the irradiated portion is cured to form a latent image. In this case, if a support is present on the photosensitive layer, and the support is transparent, the photosensitive layer can be irradiated with active light through the support; however, if the support is light-blocking, the photosensitive layer is irradiated with active light after the support is removed.

[0115] Examples of exposure methods include methods that illuminate active light in an imaging manner through a negative or positive mask pattern called the master image (mask exposure method). Methods that illuminate active light in an imaging manner can also be used via projection exposure methods. Methods that illuminate active light in an imaging manner can also be used via direct drawing exposure methods such as LDI (Laser Direct Imaging) exposure methods or DLP (Digital Light Processing) exposure methods.

[0116] As a source of active light, it can utilize known light sources, such as gas lasers like carbon arc lamps, mercury vapor arc lamps, high-pressure mercury lamps, xenon lamps, and argon lasers, solid-state lasers like YAG lasers, semiconductor lasers, and other sources that emit ultraviolet rays and effectively emit visible light.

[0117] (iii) Development steps)

[0118] In the development step, at least a portion of the photosensitive layer, excluding the photocurable portion, is removed from the substrate to form a resist pattern on the substrate.

[0119] When a support is present on the photosensitive layer, the support is removed, and then the area other than the photocurable portion (also called the unexposed portion) is removed (developed). Development methods include wet development and dry development, with wet development being widely used.

[0120] In wet development, development is performed using a developer corresponding to the photosensitive resin composition, employing a known development method. Examples of development methods include dip coating, paddle method, spraying, brush coating, tapping, scrubbing, and rocking immersion. From the viewpoint of improving resolution, high-pressure spraying can be used. Development can be carried out by combining two or more of these methods.

[0121] The composition of the developer can be appropriately selected based on the composition of the above-described photosensitive resin composition. Examples of developers include alkaline aqueous solutions and organic solvent developers.

[0122] From the perspectives of safety, stability, and good operability, alkaline aqueous solutions can be used as developers. Examples of alkalis in alkaline aqueous solutions 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 pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate; sodium tetraborate; sodium metasilicate; tetramethylammonium hydroxide; ethanolamine; ethylenediamine; diethylenetriamine; 2-amino-2-hydroxymethyl-1,3-propanediol; 1,3-diaminopropanol-2; and morpholine.

[0123] As an alkaline aqueous solution for development, 0.1–5% by mass sodium carbonate dilute solution, 0.1–5% by mass potassium carbonate dilute solution, 0.1–5% by mass sodium hydroxide dilute solution, and 0.1–5% by mass sodium tetraborate dilute solution can be used. The pH of the alkaline aqueous solution can be in the range of 9–14, and the temperature can be adjusted according to the alkaline developability of the photosensitive layer. Surfactants, defoamers, and small amounts of organic solvents to promote development can be mixed into the alkaline aqueous solution.

[0124] Examples of organic solvents used in alkaline aqueous solutions include acetone, ethyl acetate, alkoxyethanol containing alkoxy groups having 1 to 4 carbons, ethanol, isopropanol, butanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether.

[0125] Examples of organic solvents used in organic solvent developers include 1,1,1-trichloroethane, N-methylpyrrolidone, N,N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, and γ-butyrolactone. To prevent ignition, water can be added to these organic solvents to bring them to a concentration in the range of 1–20% by mass, thereby obtaining an organic solvent developer.

[0126] The method for forming a resist pattern according to this embodiment may include removing the uncured portion from the developing step and then heating at approximately 60 to 250°C or at approximately 0.2 to 10 J / cm² as needed. 2 The step of exposing the photoresist pattern to further solidify it.

[0127] [Methods for forming wiring patterns]

[0128] The wiring pattern forming method according to this embodiment includes the step of forming a conductor pattern by etching or plating a substrate having a resist pattern formed thereon by the above-described resist pattern forming method. The wiring pattern forming method may further include the step of removing the photocured portion with an alkaline aqueous solution after etching or plating.

[0129] In the plating process, a conductor layer disposed on the substrate is plated by using a resist pattern formed on the substrate as a mask. After the plating process, the resist can be removed by removing the resist pattern as described below, and the conductor layer covered with the resist can be etched to form a conductor pattern. The plating process can be electroplating or electroless plating.

[0130] On the other hand, in the etching process, the resist pattern formed on the substrate is used as a mask, and the conductor layer disposed 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 etching solutions include copper chloride solution, ferric chloride solution, alkaline etching solution, and hydrogen peroxide-based etching solution.

[0131] After etching or plating, the resist pattern on the substrate can be removed. The resist pattern can be removed, for example, by a more alkaline aqueous solution than the alkaline aqueous solution used in the development step described above. Examples of strong alkaline aqueous solutions include, for instance, a 1-10% by mass sodium hydroxide aqueous solution and a 1-10% by mass potassium hydroxide aqueous solution. The removal of the resist pattern can be carried out at a temperature of 45-65°C using a strong alkaline aqueous solution.

[0132] After plating, when removing the resist pattern, the resist-coated conductor layer is further etched to form a conductor pattern, thereby manufacturing the desired printed circuit board. The etching method can be appropriately selected based on the conductor layer to be removed. For example, the etching solution described above can be used.

[0133] The wiring pattern forming method according to this embodiment can be applied not only to the manufacture of single-layer printed circuit boards, but also to the manufacture of multi-layer printed circuit boards, and also to the manufacture of printed circuit boards with small-diameter through holes.

[0134] Example

[0135] The present invention will now be described in detail with reference to embodiments, but the present invention is not limited to the embodiments.

[0136] (1) Triphenylmethyl methacrylate (MA-Tr)

[0137] 150 mL of petroleum ether, 0.10 mol of triphenylmethyl, 0.11 mol of methacrylic acid, and 0.10 mol of triethylamine were placed in a 1000 mL three-necked flask equipped with a stirrer, a nitrogen inlet tube, and a reflux condenser, and allowed to react at room temperature for 6 hours. After removing the triethylamine hydrochloride produced as a product from the reaction solution, 100 mL of a 3% (w / w) sodium carbonate aqueous solution was added to the reaction solution, and the mixture was washed three times. The washed reaction solution was dried over magnesium sulfate, and then the solvent was removed by vacuum drying to obtain MA-Tr. The yield was 90%.

[0138] (2) Tert-butyl dimethyl methacrylate (MA-TBDMS)

[0139] 150 mL of dichloromethane, 0.20 mol of methacrylic acid, and 0.22 mol of triethylamine were placed in a 500 mL three-necked flask equipped with a stirrer, a nitrogen inlet tube, and a reflux condenser, and stirred for 10 minutes. Then, 0.21 mmol of tert-butyldimethylchlorosilane was added dropwise to the flask, and the mixture was allowed to react at room temperature for 24 hours. The reaction solution was washed twice with 3% hydrochloric acid, followed by three washes with pure water. The washed reaction solution was dried over magnesium sulfate, and then the solvent was removed by vacuum drying to obtain MA-TBDMS. The yield was 98%.

[0140] (3) Triethyl methacrylate (MA-TES)

[0141] 150 mL of dichloromethane, 0.20 mol of methacrylic acid, and 0.22 mol of triethylamine were placed in a 500 mL three-necked flask equipped with a stirrer, a nitrogen inlet tube, and a reflux condenser, and stirred for 10 minutes. Then, 0.21 mmol of triethylchlorosilane was added dropwise to the flask, and the mixture was allowed to react at room temperature for 24 hours. The reaction solution was washed twice with 3% hydrochloric acid, followed by three washes with pure water. The washed reaction solution was dried over magnesium sulfate, and then the solvent was removed by vacuum drying to obtain MA-TES. The yield was 90%.

[0142] (4) Alkali-soluble resins

[0143] (Example 1)

[0144] 96 g of propylene glycol monomethyl ether (MFG) and 64 g of toluene were placed in a 1000 mL three-necked flask equipped with a stirrer, nitrogen inlet tube, reflux condenser, dropping funnel, and thermometer, and the temperature was raised to 80 °C under a nitrogen atmosphere. In the flask, a mixture of 20 g of methacrylic acid (MA), 30 g of styrene (STC), 40 g of benzyl methacrylate (BzMA), 10 g of trimethyl methacrylate (MA-TMS), and 1 g of azobisisobutyronitrile (AIBN) was added dropwise over 3 hours. Then, a mixture of 6 g of MFG, 4 g of toluene, and 0.20 g of AIBN was added dropwise over 2 hours, followed by the further addition of 6 g of MFG and 4 g of toluene to proceed with the reaction. The reaction solution was heated to 95 °C and stirred for 1.5 hours, then cooled to room temperature to obtain a polymer solution of alkali-soluble resin (A1). The non-volatile content (solid content) of the polymer solution was 40% by mass.

[0145] (Examples 2-4)

[0146] Except for using MA, STC, BzMA and MA-TMS in the amounts shown in Table 1, polymer solutions of alkali-soluble resins (A2) to (A4) were obtained using the same method as in Example 1.

[0147] (Examples 5-8)

[0148] Except for using MA, STC, BzMA and MA-Tr in the amounts shown in Table 1, polymer solutions of alkali-soluble resins (A5) to (A8) were obtained in the same manner as in Example 1.

[0149] (Example 9)

[0150] Except for the use of MA, STC, BzMA and 2-(trimethylsiloxy)ethyl methacrylate (HEMA-TMS) in the proportions shown in Table 1, a polymer solution of alkali-soluble resin (A9) was obtained using the same method as in Example 1.

[0151] (Examples 10-12)

[0152] Except for using MA, methyl methacrylate (MMA), STC, BzMA and HEMA-TMS in the proportions shown in Table 1, polymer solutions of alkali-soluble resins (A10) to (A12) were obtained in the same manner as in Example 1.

[0153] (Example 13)

[0154] Except for using MA, STC, BzMA and MA-TBDMS in the amounts shown in Table 1, a polymer solution of alkali-soluble resin (A13) was obtained in the same manner as in Example 1.

[0155] (Example 14)

[0156] Except for the use of MA, STC, BzMA and MA-TES in the amounts shown in Table 1, a polymer solution of alkali-soluble resin (A14) was obtained using the same method as in Example 1.

[0157] (Comparative Example 1)

[0158] Except for using MA, STC and BzMA in the amounts shown in Table 1, a polymer solution of alkali-soluble resin (B1) was obtained using the same method as in Example 1.

[0159] (Comparative Examples 2-3)

[0160] Except for using MA, MMA, STC and BzMA in the amounts shown in Table 1, polymer solutions of alkali-soluble resins (B2) to (B3) were obtained in the same manner as in Example 1.

[0161] (weight-average molecular weight)

[0162] 120 mg of polymer solution was collected and dissolved in 5 mL of THF to prepare a sample for Mw determination. Mw was determined by gel permeation chromatography (GPC) and converted using a standard polystyrene calibration curve. The GPC conditions are shown below.

[0163] (GPC conditions)

[0164] Pump: Hitachi L-6000 (manufactured by Hitachi, Ltd.)

[0165] Tubes: Gelpack GL-R420, Gelpack GL-R430 and Gelpack GL-R440 (manufactured by Hitachi Chemical Co., Ltd., tube size: 10.7mmφ×300mm)

[0166] Eluent: Tetrahydrofuran (THF)

[0167] Measurement temperature: 40℃

[0168] Injection volume: 200μL

[0169] Pressure: 49 kgf / cm 2 (4.8MPa)

[0170] Flow rate: 2.05 mL / min

[0171] Detector: Hitachi L-3300RI (manufactured by Hitachi, Ltd.)

[0172] [Table 1]

[0173]

[0174] (5) Photosensitive resin composition

[0175] A photosensitive resin composition was prepared by mixing the components in the proportions (parts by mass) shown in Table 2 relative to 140 parts by mass of the above polymer solution (alkali-soluble resin: 56 parts by mass).

[0176] As shown below, the details of each component are presented in Table 2.

[0177] (Photopolymerizable compounds)

[0178] FA-321M (Registered Trademark): 2,2-Bis(4-(Methacryloxypentethoxy)phenyl)propane (manufactured by Hitachi Chemical Co., Ltd.)

[0179] FA-023M (Registered Trademark): Polyalkylene glycol di(meth)acrylate (manufactured by Hitachi Chemical Co., Ltd.)

[0180] FA-MECH (registered trademark): (2-hydroxy-3-chloro)propyl-2-methacryloyloxyethyl phthalate (manufactured by Hitachi Chemical Co., Ltd.)

[0181] (Photopolymerization initiator)

[0182] BCIM (registered trademark): 2,2′-bis(2-chlorophenyl)-4,4′,5,5′-tetraphenylbiimidazole (manufactured by Hampford Research Inc.)

[0183] (Sensitizer)

[0184] DBA (registered trademark): 9,10-Dibutoxyanthracene (Kawasaki Chemical Industry Co., Ltd.)

[0185] (Photochromic agent)

[0186] LCV: Colorless Crystal Violet (Yamada Chemical Co., Ltd.)

[0187] (Adhesive-enhancing agent)

[0188] SF-808H: A mixture of carboxybenzotriazole, 5-amino-1H-tetrazole, and methoxypropanol (Sanwa Kasei Co., Ltd.)

[0189] (dye)

[0190] MKG: Malachite Green (Osaka Organic Chemical Industry Co.,Ltd.)

[0191] [Table 2]

[0192]

[0193] (6) Photosensitive element

[0194] A photosensitive resin composition was coated onto a 16 μm thick polyethylene terephthalate (PET) film (registered trademark "G2J", manufactured by Teijin Film Solution Co., Ltd.) (support) and subsequently dried in hot air convection dryers at 75°C and 125°C to form a photosensitive layer with a dry thickness of 25 μm. A polypropylene film (product name "NF-13", manufactured by Tamapoly Co., Ltd.) (protective layer) was then bonded onto the photosensitive layer to obtain photosensitive elements having a support, photosensitive layer, and protective layer sequentially stacked.

[0195] [evaluate]

[0196] (Degree of hydrophilicity)

[0197] 7g of monomer was placed in a 20mL glass bottle, ion-exchanged water was added, and the mixture was allowed to stand at 23°C for 12 hours. The monomer was then recovered using a syringe, and its water content was determined by the Karl Fischer method. The water content (mass%) of the monomer was considered its degree of hydrophilicity. The degree of hydrophilicity of each monomer is shown in Table 3.

[0198] [Table 3]

[0199] monomer hydrophilicity MA 3.2 (Reference value) MMA 1.2 STC 0.1 BzMA 0.4 MA-TMS 0.5 MA-Tr 0.2 MA-TBDMA 0.1 MA-TES 0.1

[0200] The initial degree of hydrophilicity, the degree of hydrophilicity after polarity conversion, and the rate of increase in hydrophilicity of the alkali-soluble resin were calculated based on the hydrophilicity of the monomers and the copolymerization ratio of the monomers. The degree of hydrophilicity of the alkali-soluble resins of the examples is shown in Table 4, and the degree of hydrophilicity of the alkali-soluble resins of the comparative examples is shown in Table 5.

[0201] (Layered structure)

[0202] A copper-clad laminate (registered trademark "MCL-E-67", manufactured by Hitachi Chemical Co., Ltd.), with copper foil (35 μm thick) laminated on both sides of a glass fiber reinforced epoxy resin layer, was cleaned with water and acid, then cleaned again with water, and dried in an air stream. The copper-clad laminate was heated to 80°C, and a photosensitive element was laminated onto the copper surface of the copper-clad laminate. While removing the protective layer using a heated roller at 110°C, lamination was performed on the substrate at a pressure of 0.4 MPa and a roller speed of 1.0 m / min. This yielded a laminate consisting of a copper-clad laminate, a photosensitive layer, and a support layer sequentially stacked.

[0203] (Reproducible)

[0204] A photosensitive layer with a thickness of 25 μm was laminated onto a substrate, and then developed at 30°C using a 1% (w / w) sodium carbonate aqueous solution. The development time at which the residual film disappeared was measured. Cases with a development time of less than 20 seconds were rated as "A", and cases with a development time of less than 20 seconds were rated as "B".

[0205] (resolution)

[0206] On the support of the laminate, a glass chrome photo tool (resolution negative: wiring pattern with linewidth / space width of x / x (x: 1~30, unit: μm)) was used as a negative for resolution evaluation, and exposed to an energy of 17.0 with the remaining levels of a developed Hitachi 41-step tablet. After exposure, the photosensitive layer was developed using the same method as for sensitivity evaluation.

[0207] In the resist pattern obtained by completely removing the unexposed portions (unexposed areas) after development and forming straight or broken lines (exposed areas), the minimum space width value is used to evaluate the resolution. Cases with a minimum space width of less than 15 μm are rated as "A", cases with a minimum space width of 15–20 μm are rated as "B", and cases with a minimum space width of more than 20 μm are rated as "C".

[0208] (Peeling properties)

[0209] A laminate with a 25 μm thick photosensitive layer stacked on a substrate was irradiated with 30 mJ at 405 nm using a direct-draw exposure apparatus. Spray development was then performed using a 1% (w / w) sodium carbonate aqueous solution at 30°C for twice the minimum development time (the shortest time to remove unexposed areas), thereby removing the unexposed areas (development treatment). After development treatment, a test piece with a 40 mm × 50 mm cured film formed on the substrate was obtained. The test piece was immersed in a 3% (w / w) sodium hydroxide aqueous solution at 50°C, and the time until the cured film peeled off from the substrate was measured. Cases with a peeling time of less than 50 seconds were rated "A", cases with a peeling time of 50 seconds or more but less than 60 seconds were rated "B", and cases with a peeling time of 60 seconds or more were rated "C".

[0210] [Table 4]

[0211]

[0212]

[0213] [Table 5]

[0214]

[0215] Based on the above results, it can be confirmed that the photosensitive resin composition containing an alkali-soluble resin having a structural unit is compatible in terms of developability, resolution and peelability, and the structural unit has a polarity conversion group.

[0216] Symbol Explanation

[0217] 1-Photosensitive element, 2-Support, 3-Photosensitive layer, 4-Protective layer.

Claims

1. An alkali-soluble resin comprising a structural unit having a polarity-converting group, a structural unit having a carboxyl group, and a structural unit based on (meth)acrylate, wherein, The polar conversion group has a group that is not eliminated under weakly basic conditions but is eliminated under strongly basic conditions, and is represented by the group of the following formula (1). Among them, R 2 It indicates trimethylsilyl, triethylsilyl, tert-butyldimethylsilyl, or triphenylmethyl.

2. The alkali-soluble resin according to claim 1, wherein, The structural unit with the polarity conversion group is based on the structural unit of a compound represented by the following formula (2). Among them, R 1 L represents a hydrogen atom or a methyl group. 1 R represents an alkylene group having 1 to 6 carbon atoms. 2 It indicates trimethylsilyl, triethylsilyl, tert-butyldimethylsilyl, or triphenylmethyl.

3. The alkali-soluble resin according to claim 1 or 2, wherein, The content of the structural unit with the polar conversion group is 3 to 30% by mass relative to the total amount of monomers constituting the alkali-soluble resin.

4. The alkali-soluble resin according to claim 1 or 2, wherein, The content of structural units derived from the (meth) methyl acrylate is 5 to 50% by mass relative to the total amount of monomers constituting the alkali-soluble resin.

5. A photosensitive resin composition comprising: The adhesive resin contains the alkali-soluble resin according to any one of claims 1 to 4; Photopolymerizable compounds; and Photopolymerization initiator.

6. A photosensitive element comprising: Support body; and The photosensitive layer formed on the support, The photosensitive layer comprises the photosensitive resin composition of claim 5.

7. A method for forming a resist pattern, comprising: The step of forming a photosensitive layer on a substrate using the photosensitive resin composition of claim 5 or the photosensitive element of claim 6; The step of irradiating at least a portion of the photosensitive layer with active light to form a photocurable portion; and The step of removing at least a portion of the photosensitive layer, excluding the photocurable portion, from the substrate to form a resist pattern.

8. A method for forming a wiring pattern, comprising the step of forming a conductor pattern by etching or plating a substrate having a resist pattern formed thereon by the resist pattern forming method of claim 7.

9. The method for forming a wiring pattern according to claim 8, further comprising the step of removing the photocured portion with an alkaline aqueous solution after the etching process or the plating process.

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