Photosensitive element and method for forming resist pattern

Abstract

To provide a photosensitive element having a photosensitive layer which has high sensitivity to actinic rays and is capable of obtaining a resist pattern having space portions with a high aspect ratio. [Solution] A photosensitive element comprising a support and a photosensitive layer formed on the support using a photosensitive resin composition containing a binder polymer, a photopolymerizable compound, a photopolymerization initiator, and a coumarin-based sensitizer, wherein the photosensitive layer has a thickness of 30 μm or more.

Description

[Technical Field]

[0001] The present disclosure relates to a photosensitive element and a method for forming a resist pattern. [Background technology]

[0002] Photosensitive materials are used as resist materials for producing conductor patterns in the fields of manufacturing semiconductor integrated circuits (LSIs), wiring boards, and the like. For example, in the manufacture of wiring boards, a resist pattern is formed using a photosensitive resin composition, and then a conductor pattern, metal posts, and the like are formed by plating. Specifically, (1) a photosensitive layer is formed on a substrate using a photosensitive resin composition, (2) the photosensitive layer is exposed to light through a predetermined mask pattern, (3) portions where the conductor pattern, metal posts, and the like are to be formed are selectively removed (peeled off) by development to form a resist pattern, and (4) a conductor layer such as copper is formed on the removed portions by plating, and then the resist pattern is removed, thereby producing a wiring board equipped with a conductor pattern, metal posts, and the like (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-356852 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, for electronic components such as inductors, the formation of a conductor pattern having a conductor layer with a high aspect ratio while the layer thickness is large has been considered. Such a conductor pattern can be obtained, for example, by irradiating a photosensitive layer with light, removing the unexposed areas to form spaces, and then forming a conductor layer in the spaces. Therefore, for a photosensitive element for obtaining a photosensitive layer as a thick film, it is necessary to obtain a resist pattern having spaces with a high aspect ratio.

[0005] Furthermore, in addition to coils (conductive coils) of inductors (such as power inductors), the increasing number of terminals due to the higher density of semiconductor chips also requires high aspect ratios for copper pillars and the like that constitute the connecting portions of semiconductor chips, and there is a demand for photosensitive elements that include a photosensitive layer that can form, with high resolution, coil-shaped resist patterns for forming high aspect ratio coils and via hole patterns for forming copper pillars, etc. The photosensitive layer is also required to have high sensitivity to actinic rays.

[0006] An object of the present disclosure is to provide a photosensitive element having a photosensitive layer that has high sensitivity to actinic rays and that can provide a resist pattern having space portions with a high aspect ratio, and a method for forming a resist pattern using the same. [Means for solving the problem]

[0007] In order to solve the above problems, the present disclosure provides the following photosensitive element and method for forming a resist pattern.

[0008] [1] A photosensitive element comprising: a support; and a photosensitive layer formed on the support using a photosensitive resin composition containing a binder polymer, a photopolymerizable compound, a photopolymerization initiator, and a coumarin-based sensitizer, wherein the photosensitive layer has a thickness of 30 μm or more. [2] The photosensitive element according to [1] above, wherein the binder polymer has benzyl (meth)acrylate as a monomer unit. [3] The photosensitive element according to [2] above, wherein the content of benzyl (meth)acrylate in the binder polymer is 10 to 60 mass % based on the total amount of monomer units constituting the binder polymer. [4] The photosensitive element according to any one of the above [1] to [3], wherein the binder polymer has styrene as a monomer unit. [5] The photosensitive element according to [4] above, wherein the binder polymer has a styrene content of 10 to 50 mass % based on the total amount of monomer units constituting the binder polymer. [6] The photosensitive element according to any one of the above [1] to [5], wherein the binder polymer has alkyl (meth)acrylate as a monomer unit. [7] The photosensitive element according to [6] above, wherein the content of the alkyl (meth)acrylate in the binder polymer is 5 to 40 mass % based on the total amount of monomer units constituting the binder polymer. [8] The photosensitive element according to any one of the above [1] to [7], wherein the binder polymer has (meth)acrylic acid as a monomer unit. [9] The photosensitive element according to [8] above, wherein the binder polymer has a (meth)acrylic acid content of 10 to 40 mass % based on the total amount of monomer units constituting the binder polymer.

[10] The photosensitive element according to any one of the above [1] to [9], wherein the content of the coumarin-based sensitizer is 0.01 to 0.3 parts by mass per 100 parts by mass of the total amount of the binder polymer and the photopolymerizable compound.

[11] The photosensitive element according to any one of the above [1] to

[10] , wherein the photopolymerizable compound contains a (meth)acrylate having one polymerizable ethylenically unsaturated bond in the molecule.

[12] The photosensitive element according to

[11] above, wherein the content of the (meth)acrylate having one polymerizable ethylenically unsaturated bond in the molecule is 1 to 30 mass % based on the total amount of the photopolymerizable compound.

[13] The photosensitive element according to any one of the above [1] to

[12] , wherein the photopolymerizable compound includes a urethane (meth)acrylate.

[14] The photosensitive element according to any one of the above [1] to

[13] , wherein the photopolymerization initiator comprises at least one selected from the group consisting of hexaarylbiimidazole derivatives and acridine compounds.

[15] The photosensitive element according to any one of the above [1] to

[14] , wherein the photosensitive layer has a thickness of 75 μm or more.

[16] The photosensitive element according to any one of the above [1] to

[14] , wherein the photosensitive layer has a thickness of more than 100 μm.

[17] The photosensitive element according to any one of the above [1] to

[16] , which is used to form a resist pattern having spaces with an aspect ratio of 1.3 or more.

[18] The photosensitive element according to any one of the above [1] to

[17] , which is used to form a conductive coil of an inductor.

[19] The photosensitive element according to any one of the above [1] to

[17] , which is used for forming copper pillars for semiconductor connection.

[20] A method for forming a resist pattern, comprising the steps of: providing a photosensitive layer on a substrate using the photosensitive element according to any one of [1] to

[19] above; irradiating at least a portion of the photosensitive layer with actinic rays to form a photocured portion; and removing at least a portion of the photosensitive layer other than the photocured portion to form a resist pattern.

[21] The method for forming a resist pattern according to

[20] above, wherein the resist pattern has spaces with an aspect ratio of 1.3 or more. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a photosensitive element having a photosensitive layer that has high sensitivity to actinic rays and that can obtain a resist pattern having space portions with a high aspect ratio, and a method for forming a resist pattern using the same. The photosensitive element of the present disclosure can obtain a resist pattern having space portions with a high aspect ratio, so that coil-shaped (spiral-shaped) resist patterns and via hole patterns can be formed with high resolution, thereby making it possible to form inductor coils and copper pillars that constitute connecting portions of semiconductor devices with high aspect ratios. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic cross-sectional view illustrating a photosensitive element according to one embodiment of the present disclosure. [Figure 2] 1A to 1C are schematic cross-sectional views showing an example of a method for manufacturing a laminate. [Figure 3] 1 is an electron microscope photograph of a square coil pattern formed using the photosensitive element of Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described in detail.

[0012] As used herein, a numerical range "A or greater" refers to a range exceeding A and A. A numerical range "A or less" refers to a range exceeding A and A. In the numerical ranges described in this specification, the upper or lower limit of a certain numerical range can be arbitrarily combined with the upper or lower limit of another numerical range. In the numerical ranges described herein, the upper or lower limit of the numerical range may be replaced with a value shown in the examples. "A or B" may include either A or B, or both. Unless otherwise specified, the materials exemplified herein can be used alone or in combination of two or more. When multiple substances corresponding to each component are present in the composition, the content of each component in the composition refers to the total amount of the multiple substances present in the composition, unless otherwise specified. The term "layer" encompasses structures that are formed over the entire surface as well as structures that are formed only partially when observed in a plan view. The term "process" does not only refer to an independent process, but also includes processes that cannot be clearly distinguished from other processes as long as the intended effect of the process is achieved. "(Meth)acrylate" means at least one of acrylate and its corresponding methacrylate. The same applies to other similar expressions such as "(meth)acrylic acid." Unless otherwise specified, an "alkyl group" may be linear, branched, or cyclic. The content of monomer units of a (meth)acrylic acid compound (e.g., alkyl (meth)acrylate) refers to the total content of monomer units of an acrylic acid compound and monomer units of a methacrylic acid compound.

[0013] In this specification, when a composition contains multiple substances corresponding to each component, the amount of each component refers to the total amount of those multiple substances present in the composition, unless otherwise specified. In this specification, the term "solid content" refers to the non-volatile content of a photosensitive resin composition excluding volatile substances (water, solvent, etc.). In other words, the term "solid content" refers to components other than the solvent that remain unvolatilized during drying of the photosensitive resin composition, as described below, and includes those that are liquid, syrup-like, or waxy at room temperature (25°C).

[0014] [Photosensitive element] The photosensitive element according to this embodiment includes a support and a photosensitive layer provided on the support. FIG. 1 is a schematic cross-sectional view showing a photosensitive element according to one embodiment of the present disclosure. The photosensitive element 1 shown in FIG. 1 includes a photosensitive layer 1a and a support (support film) 1b that supports the photosensitive layer 1a. The photosensitive layer is a layer formed using a photosensitive resin composition containing (A) a binder polymer (hereinafter sometimes referred to as "component (A)"), (B) a photopolymerizable compound (hereinafter sometimes referred to as "component (B)"), (C) a photopolymerization initiator (hereinafter sometimes referred to as "component (C)"), and (D) a coumarin-based sensitizer (hereinafter sometimes referred to as "component (D)"). The photosensitive layer has a thickness of 30 μm or more.

[0015] In the photosensitive element according to this embodiment, the photosensitive layer is a thick layer having a thickness of 30 μm or more. Conventionally, when the photosensitive layer is thick, it has been difficult to form spaces with a high aspect ratio due to reasons such as the difficulty of light penetrating to the bottom of the photosensitive layer, making it difficult to obtain high resolution. Furthermore, when the photosensitive layer is thick, it has tended to be difficult to achieve both high sensitivity and high resolution. Furthermore, conventional photosensitive elements have not necessarily been suitable for forming coil-shaped resist patterns and via hole patterns. In contrast, the photosensitive element according to this embodiment uses the above components (A) to (D) in the photosensitive layer, making it possible to form a resist pattern having spaces with a high aspect ratio while maintaining high sensitivity to actinic rays, and thus forming a coil-shaped resist pattern and a via hole pattern with high resolution.

[0016] The photosensitive element according to this embodiment is suitable for forming a resist pattern having spaces with an aspect ratio of 1.3 or more. A resist pattern with a high aspect ratio can be used to obtain conductor patterns and metal posts with high aspect ratios. The photosensitive element according to this embodiment can be suitably used in the manufacture of electronic components such as inductors (e.g., electronic circuit boards) and semiconductor devices, and is particularly suitable for forming conductive coils for inductors (e.g., power inductors) and copper pillars for semiconductor connections (for forming via hole patterns for forming copper pillars).

[0017] <Support> Examples of the support include polyester films such as polyethylene terephthalate (PET) film, polybutylene terephthalate (PBT) film, and polyethylene-2,6-naphthalate (PEN) film; and polyolefin films such as polypropylene film and polyethylene film.

[0018] The haze of the support may be 0.01 to 5.0%, 0.01 to 1.5%, 0.01 to 1.0%, or 0.01 to 0.5%. Haze can be measured using a commercially available haze meter (turbidity meter) in accordance with the method specified in JIS K7105. Haze can be measured using a commercially available turbidity meter such as NDH-5000 (trade name, manufactured by Nippon Denshoku Industries Co., Ltd.).

[0019] The thickness of the support may be 1 to 200 μm, 1 to 100 μm, 1 to 60 μm, 5 to 60 μm, 10 to 60 μm, 10 to 50 μm, 10 to 40 μm, 10 to 30 μm, or 10 to 25 μm. When the thickness of the support is 1 μm or more, it is easy to prevent the support from breaking when peeling it off. When the thickness of the support is 200 μm or less, it is easy to obtain economic benefits.

[0020] <Photosensitive layer> The photosensitive layer is a layer formed using a photosensitive resin composition. The photosensitive resin composition contains the above-mentioned components (A) to (D). Each component of the photosensitive resin composition will be described below.

[0021] (Component (A): Binder polymer) The photosensitive resin composition contains a binder polymer as component (A). Component (A) can have a polymerizable monomer as a monomer unit (structural unit) and can be obtained, for example, by radical polymerization of the polymerizable monomer. Examples of the polymerizable monomer include alkyl (meth)acrylate, benzyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, glycidyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, (meth)acrylic acid, α-bromo(meth)acrylic acid, α-chloro(meth)acrylic acid, and β-furyl(meth)acrylic acid. , β-styryl(meth)acrylic acid, acrylamide (diacetone(meth)acrylamide, etc.), (meth)acrylonitrile, styrene compounds (styrene or styrene derivatives), vinyl alcohol ethers (vinyl-n-butyl ether, etc.), maleic acid, maleic anhydride, maleic acid monoesters (monomethyl maleate, monoethyl maleate, monoisopropyl maleate, etc.), fumaric acid, cinnamic acid, α-cyanocinnamic acid, itaconic acid, crotonic acid, propiolic acid, etc. The photosensitive resin composition does not need to contain a binder polymer having an aromatic ring as component (A).

[0022] From the viewpoint of facilitating the production of a resist pattern having space portions with a high aspect ratio, the component (A) may contain (meth)acrylic acid as a monomer unit. From the viewpoint of facilitating the production of a resist pattern having space portions with a high aspect ratio, the content of (meth)acrylic acid in the component (A) may be within the following ranges based on the total amount of monomer units constituting the component (A). The content of (meth)acrylic acid may be 5% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, 25% by mass or more, or 30% by mass or more. The content of (meth)acrylic acid may be 60% by mass or less, 50% by mass or less, 45% by mass or less, 40% by mass or less, 35% by mass or less, or 30% by mass or less. From the above viewpoints, the content of (meth)acrylic acid may be 5 to 60% by mass, or 10 to 40% by mass.

[0023] From the viewpoint of facilitating the production of a resist pattern having space portions with a high aspect ratio, component (A) may contain an alkyl (meth)acrylate as a monomer unit. From the viewpoint of facilitating the production of a resist pattern having space portions with a high aspect ratio, the content of alkyl (meth)acrylate in component (A) may be within the following ranges based on the total amount of monomer units constituting component (A). The content of alkyl (meth)acrylate may be 5% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, 25% by mass or more, 30% by mass or more, or 35% by mass or more. The content of alkyl (meth)acrylate may be 60% by mass or less, 50% by mass or less, 45% by mass or less, 40% by mass or less, or 35% by mass or less. From the above viewpoint, the content of alkyl (meth)acrylate may be 5 to 60% by mass, or 5 to 40% by mass.

[0024] The alkyl group of the alkyl (meth)acrylate may have a substituent, such as a hydroxy group, a carboxy group, a carboxylate salt group, an alkoxy group, an amino group, a halogeno group, or a glycidyl group.

[0025] From the viewpoint of facilitating the production of a resist pattern having space portions with a high aspect ratio, component (A) may contain styrene as a monomer unit. From the viewpoint of facilitating the production of a resist pattern having space portions with a high aspect ratio, the styrene content in component (A) may be within the following ranges based on the total amount of monomer units constituting component (A). The styrene content may be 5% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, 25% by mass or more, 30% by mass or more, or 35% by mass or more. The styrene content may be 60% by mass or less, 50% by mass or less, 45% by mass or less, 40% by mass or less, or 35% by mass or less. From the above viewpoint, the styrene content may be 5 to 60% by mass, or may be 10 to 50% by mass.

[0026] Component (A) may contain benzyl (meth)acrylate as a monomer unit, from the viewpoints of facilitating the formation of a resist pattern having space portions with a high aspect ratio and improving both the adhesion and release properties of the resist pattern. The content of benzyl (meth)acrylate in component (A) may be within the following ranges, based on the total amount of monomer units constituting component (A), from the viewpoints of facilitating the formation of a resist pattern having space portions with a high aspect ratio and improving both the adhesion and release properties of the resist pattern. The content of benzyl (meth)acrylate may be 5% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, 25% by mass or more, 30% by mass or more, or 35% by mass or more. The content of benzyl (meth)acrylate may be 60% by mass or less, 50% by mass or less, 45% by mass or less, 40% by mass or less, or 35% by mass or less. From the above viewpoint, the content of benzyl (meth)acrylate may be 5 to 60% by mass, or may be 10 to 60% by mass.

[0027] From the viewpoint of easily obtaining a resist pattern having space portions with a high aspect ratio, the component (A) may have, as a monomer unit, at least one selected from the group consisting of (meth)acrylic acid, an alkyl (meth)acrylate, styrene, and benzyl (meth)acrylate, or may have, as monomer units, all of (meth)acrylic acid, an alkyl (meth)acrylate, styrene, and benzyl (meth)acrylate.

[0028] The weight average molecular weight (Mw) of component (A) may be within the following range, from the viewpoint of easily obtaining a resist pattern having space portions with a high aspect ratio. From the viewpoint of easily obtaining excellent developer resistance, the weight average molecular weight may be 10,000 or more, 15,000 or more, 20,000 or more, 25,000 or more, 30,000 or more, 35,000 or more, 40,000 or more, 45,000 or more, or 50,000 or more. From the viewpoint of easily suppressing long development times, the weight average molecular weight may be 300,000 or less, 150,000 or less, 100,000 or less, 80,000 or less, 60,000 or less, 55,000 or less, or 50,000 or less. From the above viewpoint, the weight average molecular weight may be 10,000 to 300,000.

[0029] The dispersity (weight average molecular weight / number average molecular weight) of component (A) may be within the following range, from the viewpoint of facilitating the production of a resist pattern having space portions with a high aspect ratio. The dispersity may be 1.0 or more, 1.5 or more, 1.8 or more, 2.0 or more, 2.1 or more, 2.2 or more, or 2.3 or more. The dispersity may be 3.0 or less, 2.8 or less, 2.5 or less, or 2.4 or less. From the above viewpoints, the dispersity may be 1.0 to 3.0.

[0030] The weight-average molecular weight and number-average molecular weight in this specification are values ​​measured by gel permeation chromatography (GPC) and converted using standard polystyrene as a standard sample. The following GPC conditions can be used. {GPC conditions} Pump: Hitachi L-6000 type (manufactured by Hitachi, Ltd.) Columns: Gelpack GL-R440, Gelpack GL-R450, and Gelpack GL-R400M (Showa Denko Materials Technoservice Co., Ltd., column specifications: 10.7 mmφ × 300 mm) Eluent: tetrahydrofuran Measurement temperature: 40℃ Injection volume: 200μL Flow rate: 2.05mL / min Detector: L-2490 type RI (Hitachi High-Tech Corporation)

[0031] From the viewpoint of facilitating the production of a resist pattern having space portions with a high aspect ratio, the acid value of component (A) may be within the following range. The acid value may be 50 mgKOH / g or more, 80 mgKOH / g or more, 100 mgKOH / g or more, 120 mgKOH / g or more, 150 mgKOH / g or more, 180 mgKOH / g or more, or 190 mgKOH / g or more. The acid value may be 250 mgKOH / g or less, 230 mgKOH / g or less, 220 mgKOH / g or less, 210 mgKOH / g or less, or 200 mgKOH / g or less. From the above viewpoint, the acid value may be 50 to 250 mgKOH / g, 50 to 200 mgKOH / g, or 100 to 200 mgKOH / g.

[0032] The acid value can be measured using the following procedure. First, weigh the binder polymer into an Erlenmeyer flask. Next, add a mixed solvent (mass ratio: toluene / methanol = 70 / 30) to dissolve the binder polymer, and then add phenolphthalein solution as an indicator. The acid value is then obtained by titration using 0.1 mol / L (N / 10) potassium hydroxide solution (alcohol solution).

[0033] From the viewpoint of easily obtaining a resist pattern having space portions with a high aspect ratio, the content of component (A) in the photosensitive resin composition may be within the following ranges relative to 100 parts by mass of the total amount of components (A) and (B): The content of component (A) may be 10 parts by mass or more, 20 parts by mass or more, 30 parts by mass or more, 35 parts by mass or more, 40 parts by mass or more, 45 parts by mass or more, 50 parts by mass or more, or 55 parts by mass or more. The content of component (A) may be 90 parts by mass or less, 80 parts by mass or less, 75 parts by mass or less, 70 parts by mass or less, 65 parts by mass or less, or 60 parts by mass or less. From the above viewpoints, the content of component (A) may be 10 to 90 parts by mass.

[0034] ((B) component: photopolymerizable compound) The photosensitive resin composition contains a photopolymerizable compound as component (B), which may be a compound having at least one ethylenically unsaturated bond in the molecule.

[0035] Examples of the ethylenically unsaturated bond include an α,β-unsaturated carbonyl group (such as a (meth)acryloyl group). Examples of the photopolymerizable compound having an α,β-unsaturated carbonyl group include an α,β-unsaturated carboxylic acid ester of a polyhydric alcohol, a bisphenol-type (meth)acrylate, an α,β-unsaturated carboxylic acid adduct of a glycidyl group-containing compound, a (meth)acrylate having a urethane bond, nonylphenoxy polyethyleneoxy (meth)acrylate (also known as nonylphenoxy polyethylene glycol (meth)acrylate), a (meth)acrylate having a phthalic acid skeleton, and a (meth)acrylic acid alkyl ester.

[0036] Examples of the α,β-unsaturated carboxylic acid ester of a polyhydric alcohol include polyethylene glycol di(meth)acrylate having 2 to 14 ethylene groups, polypropylene glycol di(meth)acrylate having 2 to 14 propylene groups, polyethylene-polypropylene glycol di(meth)acrylate having 2 to 14 ethylene groups 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 skeleton derived from dipentaerythritol or pentaerythritol. "EO-modified" means having a block structure of ethylene oxide (EO) groups, and "PO-modified" means having a block structure of propylene oxide (PO) groups.

[0037] Component (B) may contain a polyalkylene glycol di(meth)acrylate, from the viewpoints of readily improving the flexibility of the resist pattern and facilitating the production of a resist pattern having space portions with a high aspect ratio. The polyalkylene glycol di(meth)acrylate may have at least one of an EO group and a PO group, or may have both an EO group and a PO group. In a polyalkylene glycol di(meth)acrylate having both an EO group and a PO group, the EO groups and the PO groups may each be present in succession in a block form, or may be present randomly. The PO group may be either an oxy-n-propylene group or an oxyisopropylene group. In a (poly)oxyisopropylene group, the secondary carbon of the propylene group may be bonded to an oxygen atom, and the primary carbon may be bonded to an oxygen atom.

[0038] Commercially available polyalkylene glycol di(meth)acrylate products include FA-023M (manufactured by Showa Denko Materials Co., Ltd.), FA-024M (manufactured by Showa Denko Materials Co., Ltd.), and NK Ester HEMA-9P (manufactured by Shin-Nakamura Chemical Co., Ltd.).

[0039] Component (B) may contain a urethane (meth)acrylate, which can improve the flexibility of the resist pattern and facilitate the production of a resist pattern with spaces having a high aspect ratio. The urethane (meth)acrylate is a (meth)acrylate having a urethane bond. Examples of the (meth)acrylate having a urethane bond include an addition reaction product of a (meth)acrylic monomer having a hydroxy group at the β-position with a diisocyanate (such as isophorone diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, or 1,6-hexamethylene diisocyanate), tris((meth)acryloxytetraethylene glycol isocyanate)hexamethylene isocyanurate, EO-modified urethane di(meth)acrylate, PO-modified urethane di(meth)acrylate, and EO·PO-modified urethane di(meth)acrylate.

[0040] Commercially available EO-modified urethane di(meth)acrylates include UA-11 (manufactured by Shin-Nakamura Chemical Co., Ltd.) and UA-21EB (manufactured by Shin-Nakamura Chemical Co., Ltd.), and commercially available EO·PO-modified urethane di(meth)acrylates include UA-13 (manufactured by Shin-Nakamura Chemical Co., Ltd.).

[0041] From the viewpoint of easily obtaining a resist pattern having spaces with a high aspect ratio and easily improving resolution and release properties after curing, component (B) may contain a bisphenol-type (meth)acrylate or a bisphenol A-type (meth)acrylate. Examples of bisphenol A-type (meth)acrylates include 2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane (e.g., 2,2-bis(4-((meth)acryloxypentaethoxy)phenyl)propane), 2,2-bis(4-((meth)acryloxypolypropoxy)phenyl)propane, 2,2-bis(4-((meth)acryloxypolyethoxypolypropoxy)phenyl)propane, 2,2-bis(4-((meth)acryloxypolybutoxy)phenyl)propane, and 2,2-bis(4-((meth)acryloxypentaethoxy)phenyl)propane. The component (B) may contain 2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane, from the viewpoint of making it easier to obtain a resist pattern having space portions with a high aspect ratio, and from the viewpoint of making it easier to further improve resolution and pattern formability.

[0042] Commercially available products of 2,2-bis(4-((meth)acryloxydipropoxy)phenyl)propane include BPE-200 (manufactured by Shin-Nakamura Chemical Co., Ltd.). Commercially available products of 2,2-bis(4-(methacryloxypentaethoxy)phenyl)propane include BPE-500 (manufactured by Shin-Nakamura Chemical Co., Ltd.) and FA-321M (manufactured by Showa Denko Materials Co., Ltd.).

[0043] From the viewpoint of improving resist strippability and resist dispersibility in a developer, component (B) may contain a (meth)acrylate having one polymerizable ethylenically unsaturated bond in the molecule. Furthermore, the (meth)acrylate having one polymerizable ethylenically unsaturated bond in the molecule may be an aromatic monofunctional (meth)acrylate. The aromatic monofunctional (meth)acrylate is a monofunctional (meth)acrylate having an aromatic hydrocarbon group. Examples of aromatic monofunctional (meth)acrylates include nonylphenoxy polyethyleneoxy (meth)acrylate and (meth)acrylates having a phthalic acid skeleton.

[0044] Examples of nonylphenoxy polyethyleneoxy(meth)acrylates include nonylphenoxytetraethyleneoxy(meth)acrylate, nonylphenoxypentaethyleneoxy(meth)acrylate, nonylphenoxyhexaethyleneoxy(meth)acrylate, nonylphenoxyheptaethyleneoxy(meth)acrylate, nonylphenoxyoctaethyleneoxy(meth)acrylate, nonylphenoxynonaethyleneoxy(meth)acrylate, nonylphenoxydecaethyleneoxy(meth)acrylate, and nonylphenoxyundecaethyleneoxy(meth)acrylate. Commercially available nonylphenoxy polyethyleneoxy(meth)acrylates include FA-318A (manufactured by Showa Denko Materials Co., Ltd.).

[0045] Examples of (meth)acrylates having a phthalic acid skeleton include γ-chloro-β-hydroxypropyl-β'-(meth)acryloyloxyethyl-o-phthalate, β-hydroxyethyl-β'-(meth)acryloyloxyethyl-o-phthalate, β-hydroxypropyl-β'-(meth)acryloyloxyethyl-o-phthalate, etc. Commercially available γ-chloro-β-hydroxypropyl-β'-methacryloyloxyethyl-o-phthalate includes FA-MECH (manufactured by Showa Denko Materials Co., Ltd.).

[0046] From the viewpoint of facilitating the production of a resist pattern having space portions with a high aspect ratio, the content of the component (B) may be within the following ranges relative to 100 parts by mass of the total amount of the components (A) and (B): The content of the component (B) may be 10 parts by mass or more, 20 parts by mass or more, 25 parts by mass or more, 30 parts by mass or more, 35 parts by mass or more, or 40 parts by mass or more The content of the component (B) may be 90 parts by mass or less, 80 parts by mass or less, 70 parts by mass or less, 65 parts by mass or less, 60 parts by mass or less, 55 parts by mass or less, 50 parts by mass or less, or 45 parts by mass or less From the viewpoint above, the content of the component (B) may be 10 to 90 parts by mass.

[0047] In the component (B), the content of the (meth)acrylate having one polymerizable ethylenically unsaturated bond in the molecule may be 1 to 30 mass %, 3 to 20 mass %, or 3 to 15 mass %, based on the total amount of the component (B), from the viewpoint of improving resist strippability and resist dispersibility in a developer.

[0048] (Component (C): Photopolymerization initiator) The photosensitive resin composition contains a photopolymerization initiator as component (C). Component (C) can be a compound capable of polymerizing component (B). From the viewpoint of easily improving sensitivity and resolution in a well-balanced manner, component (C) may contain at least one compound selected from the group consisting of hexaarylbiimidazole derivatives and acridine compounds (compounds having an acridinyl group).

[0049] Examples of hexaarylbiimidazole derivatives include 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, 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-di 2,2'-bis-(2-fluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,3-difluoromethylphenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,4-difluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,5-difluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, and the like.

[0050] Examples of acridine compounds include 9-phenylacridine, 9-(p-methylphenyl)acridine, 9-(m-methylphenyl)acridine, 9-(p-chlorophenyl)acridine, 9-(m-chlorophenyl)acridine, 9-aminoacridine, 9-dimethylaminoacridine, 9-diethylaminoacridine, 9-pentylaminoacridine, bis(9-acridinyl)alkanes (1,2-bis(9-acridinyl)ethane, 1,4-bis(9-acridinyl)butane, 1,6-bis(9-acridinyl)hexane, 1,8-bis(9-acridinyl)hexane, ...4-bis(9-acridinyl)butane, 1,6-bis(9-acridinyl)hexane, 1,8-bis(9-acridinyl)hexane, 1,4-bis(9-acridinyl)butane, 1,6-bis(9-acridinyl)hexane, 1,8-bis(9-acridinyl)hexane, 1,4-bis(9-acridinyl)butane, 1,6-bis(9-acridinyl)hexane, 1,8-bis(9-acridinyl)alkane, 1,4-bis(9-acridinyl)butane, 1,6-bis(9-acridinyl)hexane, 1,8-bis(9-acridinyl)alkane, 1,4-bis(9-acridinyl)butane, 1,6-bis(9-acridinyl)hexane, 1,8-bis(9-acridinyl)alkane, 1,4-bis(9-acridinyl)butane (9-acridinyl)octane, 1,10-bis(9-acridinyl)decane, 1,12-bis(9-acridinyl)dodecane, 1,14-bis(9-acridinyl)tetradecane, 1,16-bis(9-acridinyl)hexadecane, 1,18-bis(9-acridinyl)octadecane, 1,20-bis(9-acridinyl)eicosane, etc.), 1,3-bis(9-acridinyl)-2-oxapropane, 1,3-bis(9-acridinyl)-2-thiapropane, 1,5-bis(9-acridinyl)-3-thiapentane, etc.

[0051] The content of component (C) may be within the following ranges relative to 100 parts by mass of the total of component (A) and component (B). From the viewpoint of easily improving photosensitivity, resolution, and adhesion, the content of component (C) may be 0.1 parts by mass or more, 1 part by mass or more, 2 parts by mass or more, or 3 parts by mass or more. From the viewpoint of easily achieving excellent pattern formability, the content of component (C) may be 10 parts by mass or less, 5 parts by mass or less, 4 parts by mass or less, or 3 parts by mass or less. From the above viewpoints, the content of component (C) may be 0.1 to 10 parts by mass.

[0052] (Component (D): Coumarin-based sensitizer) The photosensitive resin composition contains a coumarin-based sensitizer as component (D). The use of component (D) enables the formation of a photosensitive layer that has high sensitivity to actinic radiation and can produce a resist pattern with space portions with a high aspect ratio. The coumarin-based sensitizer provides high sensitivity even with a small amount added, while its low absorbance allows the exposed light to penetrate deep into the photosensitive layer during resist pattern formation, enhancing the photocurability of the bottom of the photosensitive layer. This makes it possible to form a resist pattern with space portions with a high aspect ratio. Furthermore, the use of component (D) enables the formation of a resist pattern with reduced residue (tailing) at the bottom of the resist and a favorable resist shape with nearly vertical side surfaces (e.g., a rectangular cross section).

[0053] An example of the component (D) is a compound represented by the following general formula (1). [ka] In the formula, Z 1 and Z 2 each independently represents a halogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 14 carbon atoms, an amino group, an alkylamino group having 1 to 10 carbon atoms, a dialkylamino group having 2 to 20 carbon atoms, a mercapto group, an alkylmercapto group having 1 to 10 carbon atoms, an allyl group, a hydroxyalkyl group having 1 to 20 carbon atoms, a carboxyl group, a carboxyalkyl group having an alkyl group with 1 to 10 carbon atoms, an acyl group having an alkyl group with 1 to 10 carbon atoms, an alkoxyl group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 1 to 20 carbon atoms, or a group containing a heterocycle; n is an integer of 0 to 4; and m is an integer of 0 to 2. 1 and m Z 2 At least two of these may form a ring.

[0054] In the general formula (1), at least one Z 1 is preferably substituted at the 7-position, and at least one Z 2is preferably substituted at the 4-position. From the viewpoint of sensitivity, it is preferable that the 3-position is not substituted.

[0055] Examples of halogen atoms in general formula (1) include fluorine, chlorine, bromine, iodine, and astatine. Examples of alkyl groups having 1 to 20 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and icosyl groups, as well as structural isomers thereof. Examples of cycloalkyl groups having 3 to 10 carbon atoms include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups. Examples of aryl groups having 6 to 14 carbon atoms include phenyl, tolyl, xylyl, biphenyl, naphthyl, anthryl, and phenanthryl groups, which may be substituted with a halogen atom, amino, nitro, cyano, mercapto, allyl, or an alkyl group having 1 to 20 carbon atoms. Examples of alkylamino groups having 1 to 10 carbon atoms include methylamino, ethylamino, propylamino, and isopropylamino groups. Examples of dialkylamino groups having 2 to 20 carbon atoms include dimethylamino, diethylamino, dipropylamino, and diisopropylamino groups. Examples of alkylmercapto groups having 1 to 10 carbon atoms include methylmercapto, ethylmercapto, and propylmercapto groups. Furthermore, examples of the hydroxyalkyl group having 1 to 20 carbon atoms include a hydroxymethyl group, a hydroxyethyl group, a hydroxypropyl group, a hydroxyisopropyl group, and a hydroxybutyl group, and examples of the carboxyalkyl group having 1 to 10 carbon atoms in the alkyl group include a carboxymethyl group, a carboxyethyl group, a carboxypropyl group, and a carboxybutyl group.Examples of acyl groups having 1 to 10 carbon atoms in the alkyl group include formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, isovaleryl, and pivaloyl. Examples of alkoxy groups having 1 to 20 carbon atoms include methoxy, ethoxy, propoxy, and butoxy. Examples of alkoxycarbonyl groups having 1 to 20 carbon atoms include methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, and butoxycarbonyl. Examples of groups containing a heterocycle include furyl, thienyl, pyrrolyl, thiazolyl, indolyl, and quinolyl.

[0056] In general formula (1), Z 1 and Z 2 are preferably each independently an alkyl group having 1 to 20 carbon atoms, an amino group, an alkylamino group having 1 to 10 carbon atoms, or a dialkylamino group having 2 to 20 carbon atoms. 1 and m Z 2 At least two of these may form a ring.

[0057] From the viewpoint of resolution and photosensitivity, the coumarin compound represented by general formula (1) is more preferably a compound represented by the following general formula (2): 1 , Z 2 and m is the above Z 1 , Z 2 and m, and Z 11 and Z 12 each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and r represents an integer of 0 to 3. 1 , m Z 2 , Z 11 and Z 12 At least two of these may form a ring. 11 and Z 12 are each independently preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms. 1and Z 2 is the same as above. [ka]

[0058] A compound represented by general formula (2), wherein m Z 2 , Z 11 and Z 12 Examples of embodiments in which at least two of the above form a ring include compounds represented by the following general formula (3) and compounds represented by the following general formula (4). [ka] In the formula, Z 1 , Z 11 , Z 12 and r is the above Z 1 , Z 11 , Z 12 and r, and Z 21 is the above Z 1 In addition, s represents an integer of 0 to 8. 1 , Z 11 and Z 12 is the same as above.

[0059] [ka] In the formula, Z 1 , Z 2 and m is the above Z 1 , Z 2 and m, and Z 31 and Z 32 are each independently the above Z 1 In addition, t represents an integer of 0 to 1, u represents an integer of 0 to 6, and v represents an integer of 0 to 6. 1 and Z 2 is the same as above.

[0060] Examples of the compound represented by general formula (2) (including compounds represented by general formulas (3) and (4)) include 7-amino-4-methylcoumarin, 7-dimethylamino-4-methylcoumarin, 7-diethylamino-4-methylcoumarin (a compound represented by the following formula (5)), 7-methylamino-4-methylcoumarin, 7-ethylamino-4-methylcoumarin, 4,6-dimethyl-7-ethylaminocoumarin (a compound represented by the following formula (6)), 4,6-diethyl-7-ethylaminocoumarin, 4,6-dimethyl-7-diethylaminocoumarin, 4,6-dimethyl-7-dimethylaminocoumarin, 4,6-diethyl-7-diethylaminocoumarin, 4,6-diethyl-7-dimethyl ... coumarin, 4,6-dimethyl-7-ethylaminocoumarin, 7-dimethylaminocyclopenta[c]coumarin (a compound represented by the following formula (7)), 7-aminocyclopenta[c]coumarin, 7-diethylaminocyclopenta[c]coumarin, 2,3,6,7,10,11-hexanhydro-1H,5H-cyclopenta[3,4][1]benzopyrano[6,7,8-ij]quinolizine 12(9H)-one, 7-diethylamino-5',7'-dimethoxy-3,3'-carbonylbiscoumarin, 3,3'-carbonylbis[7-(diethylamino)coumarin], 7-(diethylamino)-3-(2-thienyl)coumarin, and a compound represented by the following formula (8).

[0061] [ka]

[0062] Particularly preferred coumarin compounds represented by general formula (1) are compounds represented by general formula (4): By using a compound represented by general formula (4) as component (D), sensitivity, adhesion, and resolution can be significantly improved, and a resist pattern having spaces with a higher aspect ratio can be formed. These effects can also be sufficiently achieved by adding only a small amount of component (D).

[0063] The content of component (D) is, relative to 100 parts by weight of the total of components (A) and (B), for example, 0.01 parts by weight or more, preferably 0.02 parts by weight or more, more preferably 0.03 parts by weight or more, and even more preferably 0.04 parts by weight or more, from the viewpoint of further improving sensitivity, adhesion, and resolution; and, relative to 100 parts by weight of the total of components (A) and (B), for example, 0.5 parts by weight or less, preferably 0.4 parts by weight or less, more preferably 0.3 parts by weight or less, even more preferably 0.2 parts by weight or less, particularly preferably 0.15 parts by weight or less, and extremely preferably 0.1 parts by weight or less, from the viewpoint of further improving the resist pattern shape and obtaining a resist pattern having spaces with a higher aspect ratio. Furthermore, the content of component (D) may be, relative to 100 parts by weight of the total of components (A) and (B), for example, less than 0.1 parts by weight, 0.09 parts by weight or less, or even less than 0.05 parts by weight, from the viewpoint of further improving the resist pattern shape and obtaining a resist pattern having spaces with a higher aspect ratio.

[0064] The photosensitive resin composition may further contain other known photosensitizers in addition to the component (D). The content of the other sensitizers may be, for example, 0.01 to 0.50 parts by mass or 0.05 to 0.20 parts by mass per 100 parts by mass of the total of the components (A) and (B).

[0065] (Other ingredients) The photosensitive resin composition may contain a polymerization inhibitor to suppress polymerization in unexposed areas during resist pattern formation and further improve resolution. The use of a polymerization inhibitor can improve pattern formability.

[0066] The polymerization inhibitor may contain a compound represented by the following general formula (I), from the viewpoint of easily improving pattern formability. [ka]

[0067] In formula (I), R 5represents a halogen atom, a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an amino group, an aryl group, a mercapto group, an alkylmercapto group having 1 to 10 carbon atoms, a carboxylalkyl group having 1 to 10 carbon atoms in the alkyl group, an alkoxy group having 1 to 20 carbon atoms, or a heterocyclic group; a is an integer of 2 or more, b is an integer of 0 or more, a+b=6, and when b is an integer of 2 or more, R 5 may be the same or different. The aryl group may be substituted with an alkyl group having 1 to 20 carbon atoms.

[0068] R 5 R may be a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, from the viewpoint of easily improving compatibility with the component (A). 5 The alkyl group having 1 to 20 carbon atoms represented by the formula may be an alkyl group having 1 to 4 carbon atoms. a may be 2 or 3, and may also be 2, from the viewpoint of facilitating improvement in resolution.

[0069] Examples of the compound represented by the general formula (I) include catechol compounds (compounds having two hydroxy groups at the ortho positions on the benzene ring) such as catechol, 2-methylcatechol, 3-methylcatechol, 4-methylcatechol, 2-ethylcatechol, 3-ethylcatechol, 4-ethylcatechol, 2-propylcatechol, 3-propylcatechol, 4-propylcatechol, 2-n-butylcatechol, 3-n-butylcatechol, 4-n-butylcatechol, 2-tert-butylcatechol, 3-tert-butylcatechol, 4-tert-butylcatechol, and 3,5-di-tert-butylcatechol; resorcinol (resorcinol), 2-methylresorcinol, 4-methylcatechol, and 4-methylcatechol. Examples of suitable resorcinol compounds include ethylresorcinol, 5-methylresorcinol (orcinol), 2-ethylresorcinol, 4-ethylresorcinol, 2-propylresorcinol, 4-propylresorcinol, 2-n-butylresorcinol, 4-n-butylresorcinol, 2-tert-butylresorcinol, and 4-tert-butylresorcinol; hydroquinone compounds such as 1,4-hydroquinone, methylhydroquinone, ethylhydroquinone, propylhydroquinone, tert-butylhydroquinone, and 2,5-di-tert-butylhydroquinone; alkoxyquinone compounds such as methoquinone; and trihydric phenol compounds such as pyrogallol and phloroglucinol.

[0070] From the viewpoint of easily improving resolution and easily obtaining a resist pattern having space portions with a high aspect ratio, the polymerization inhibitor may contain a catechol compound, may contain an alkylcatechol, may contain at least one selected from the group consisting of 2-methylcatechol, 3-methylcatechol, 4-methylcatechol, 2-ethylcatechol, 3-ethylcatechol, 4-ethylcatechol, 2-propylcatechol, 3-propylcatechol, 4-propylcatechol, 2-n-butylcatechol, 3-n-butylcatechol, 4-n-butylcatechol, 2-tert-butylcatechol, 3-tert-butylcatechol, 4-tert-butylcatechol, and 3,5-di-tert-butylcatechol, or may contain at least one selected from the group consisting of 3-tert-butylcatechol, 4-tert-butylcatechol, and 3,5-di-tert-butylcatechol.

[0071] The content of the polymerization inhibitor may be in the following ranges relative to 100 parts by mass of the total of the components (A) and (B). The content of the polymerization inhibitor may be 0 parts by mass or more. From the viewpoint of easily allowing the photoreaction of the photocured portion to proceed sufficiently and thereby easily improving pattern formability, the content may be 0.001 parts by mass or more, 0.005 parts by mass or more, 0.01 parts by mass or more, or 0.015 parts by mass or more. From the viewpoint of easily shortening the exposure time, the content of the polymerization inhibitor may be 1 part by mass or less, less than 1 part by mass, 0.8 parts by mass or less, 0.5 parts by mass or less, 0.3 parts by mass or less, 0.2 parts by mass or less, 0.15 parts by mass or less, 0.1 parts by mass or less, 0.08 parts by mass or less, 0.05 parts by mass or less, 0.03 parts by mass or less, or 0.02 parts by mass or less. From the above viewpoints, the content of the polymerization inhibitor may be 0 to 1 part by mass, more than 0 part by mass and less than 1 part by mass, or 0.01 to 0.3 part by mass. When the polymerization inhibitor contains a catechol compound, the content of the polymerization inhibitor may be more than 0 part by mass and less than 1 part by mass.

[0072] From the viewpoint of improving bottom curing properties and resist shape, the polymerization inhibitor may contain 3,5-di-tert-butyl-4-hydroxytoluene and methoquinone. In this case, the content of 3,5-di-tert-butyl-4-hydroxytoluene may be 20 to 200 ppm by mass, and the content of methoquinone may be 10 to 100 ppm by mass, based on the total solid content of the photosensitive resin composition.

[0073] The photosensitive resin composition may contain leuco crystal violet. This facilitates a well-balanced improvement in the photosensitivity and resolution of the photosensitive layer. Leuco crystal violet has the properties of a color former (photocolor former) that absorbs light and develops a specific color, and it is believed that the above-mentioned effects are achieved due to these properties. The content of leuco crystal violet may be 0.01 to 10 parts by mass, 0.05 to 5 parts by mass, or 0.1 to 3 parts by mass per 100 parts by mass of the total amount of components (A) and (B).

[0074] The photosensitive resin composition may contain other components, such as dyes (e.g., malachite green), tribromophenyl sulfone, color formers (excluding leuco crystal violet), thermal color-development inhibitors, plasticizers (e.g., p-toluenesulfonamide), pigments, fillers, antifoaming agents, flame retardants, stabilizers, adhesion promoters, leveling agents, release promoters, antioxidants, fragrances, imaging agents, and thermal crosslinking agents.

[0075] The photosensitive layer can be formed, for example, by applying a photosensitive resin composition onto a support and then drying the composition. The photosensitive resin composition can be applied by a known method such as roll coating, comma coating, gravure coating, air knife coating, die coating, or bar coating. Drying can be carried out, for example, at 70 to 150°C for about 5 to 30 minutes.

[0076] When applying the photosensitive resin composition to a support, a solvent may be added as needed to prepare a photosensitive resin composition having a solid content of about 30 to 60% by mass, such as methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N,N-dimethylformamide, or propylene glycol monomethyl ether.

[0077] In the photosensitive element according to this embodiment, the thickness of the photosensitive layer is 30 μm or more. From the viewpoint of easily obtaining a resist pattern having space portions with a high aspect ratio, the thickness of the photosensitive layer may be 35 μm or more, 40 μm or more, 45 μm or more, 50 μm or more, 55 μm or more, 60 μm or more, 75 μm or more, 100 μm or more, or more than 100 μm. From the viewpoint of excellent peelability of the photosensitive layer, the thickness of the photosensitive layer may be 300 μm or less, 250 μm or less, 200 μm or less, 150 μm or less, or 120 μm or less. The thickness of the photosensitive layer may be the average thickness of thicknesses at 10 locations. The photosensitive layer may have the above thickness by laminating a plurality of photosensitive layers.

[0078] The photosensitive element according to this embodiment may further include a protective film on the surface of the photosensitive layer opposite the support. The protective film may be a polymer film such as a polyethylene film or a polypropylene film. The protective film may be the same polymer film as the support, or a different polymer film from the support. The adhesive strength between the protective film and the photosensitive layer may be smaller than the adhesive strength between the support and the photosensitive layer.

[0079] The form of the photosensitive element is not particularly limited, and may be in the form of a sheet or a roll wound around a core. When wound into a roll, the support may be on the outside.

[0080] <Method for forming a resist pattern and method for manufacturing a laminate> The method for forming a resist pattern according to this embodiment includes the steps of: providing a photosensitive layer on a substrate using the photosensitive element according to this embodiment (photosensitive layer forming step); irradiating at least a portion of the photosensitive layer with actinic rays to form a photocured portion (exposure step); and removing at least a portion of the photosensitive layer other than the photocured portion to form a resist pattern (development step).

[0081] In the photosensitive layer forming step, a photosensitive layer is formed on a substrate using the photosensitive element according to this embodiment. In the photosensitive layer forming step, the photosensitive layer may be formed on the substrate by laminating the photosensitive layer of the photosensitive element according to this embodiment on the substrate. When the photosensitive element has a protective film, the photosensitive layer can be laminated on the substrate after removing the protective film. In the photosensitive layer forming step, for example, the photosensitive layer of the photosensitive element is heated to about 70 to 130°C while being heated under reduced pressure or normal pressure of about 0.1 to 1 MPa (1 to 10 kgf / cm). 2 The photosensitive layer can be formed on the substrate by laminating the photosensitive layer on the substrate by pressing it with a pressure of about 1000 psi.

[0082] The substrate may be a laminate having an insulating layer and a metal layer disposed on the insulating layer, for example, a copper-clad laminate having copper foil on one or both sides of a layer made of an insulating material such as glass fiber reinforced epoxy resin.

[0083] In the exposure step, at least a portion of the photosensitive layer can be irradiated with actinic rays to form a photocured portion. In the exposure step, at least a portion of the photosensitive layer can be irradiated with actinic rays after removing the support, or at least a portion of the photosensitive layer can be irradiated with actinic rays through the support. Examples of exposure methods include a method of irradiating actinic rays imagewise through a negative or positive mask pattern called artwork (mask exposure method), a method of irradiating actinic rays imagewise by a projection exposure method, and a method of irradiating actinic rays imagewise by a direct writing exposure method such as LDI (Laser Direct Imaging) exposure method or DLP (Digital Light Processing) exposure method.

[0084] The light source of the actinic rays may be a light source that effectively emits ultraviolet light or visible light, and examples thereof include carbon arc lamps, mercury vapor arc lamps, high-pressure mercury lamps, xenon lamps, gas lasers (such as argon lasers), solid-state lasers (such as YAG lasers), and semiconductor lasers.

[0085] In the method for forming a resist pattern according to this embodiment, post-exposure bake (PEB) may be performed after the exposure step and before the development step in order to improve adhesion. The temperature when performing PEB may be 50 to 100° C. The heater may be a hot plate, a box dryer, a heating roll, or the like.

[0086] In the developing step, at least a portion of the photosensitive layer other than the photocured portion is removed from the substrate as the unexposed portion of the photosensitive layer, thereby forming a resist pattern on the substrate. In the developing step, a portion or all of the unexposed portion of the photosensitive layer is removed. When a laminate including a metal layer disposed on an insulating layer is used as the substrate, the metal layer can be exposed by removing the unexposed portion of the photosensitive layer.

[0087] When a support is present on the photosensitive layer, the support can be removed, and then the portions of the photosensitive layer other than the photocured portions (unexposed portions) can be removed (developed). As the development method, wet development or dry development can be used.

[0088] In the case of wet development, development can be carried out by a known development method using a developer appropriate for the composition of the photosensitive layer. Examples of development methods include dipping, puddling, spraying, brushing, slapping, scrubbing, and swinging immersion. From the viewpoint of easily improving resolution, a high-pressure spray method may be used. Development may be carried out by combining two or more development methods.

[0089] The composition of the developer is appropriately selected depending on the composition of the photosensitive layer, and examples of the developer include an alkaline aqueous solution and an organic solvent developer.

[0090] As the developer, an alkaline aqueous solution may be used from the viewpoints of safety, stability, and good operability. Examples of the base of the alkaline aqueous solution include alkali hydroxides (such as lithium, sodium, or potassium hydroxide), alkali carbonates (such as lithium, sodium, potassium, or ammonium carbonates or bicarbonates), alkali metal phosphates (such as potassium phosphate and sodium phosphate), alkali metal pyrophosphates (such as sodium pyrophosphate and potassium pyrophosphate), borax, sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1,3-propanediol, 1,3-diamino-2-propanol, and morpholine.

[0091] Examples of the alkaline aqueous solution include a 0.1 to 5 mass % aqueous sodium carbonate solution, a 0.1 to 5 mass % aqueous potassium carbonate solution, and a 0.1 to 5 mass % aqueous sodium hydroxide solution. The pH of the alkaline aqueous solution may be 9 to 11. The temperature of the alkaline aqueous solution can be adjusted according to the developability of the photosensitive layer.

[0092] The alkaline aqueous solution may contain, for example, a surfactant, an antifoaming agent, a small amount of an organic solvent to promote development, etc. Examples of organic solvents used in the alkaline aqueous solution include acetone, ethyl acetate, an alkoxyethanol having an alkoxy group having 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether. Examples of organic solvents used in the organic solvent developer include 1,1,1-trichloroethane, N-methylpyrrolidone, N,N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, and γ-butyrolactone. The content of the organic solvent in the organic solvent developer may be adjusted to a range of 1 to 20% by mass by mixing the organic solvent with water.

[0093] In the method for forming a resist pattern according to this embodiment, after the development step, heating at about 60 to 250°C or 0.2 to 10 J / cm may be performed as necessary. 2 The method may further include a step of further hardening the resist pattern by exposing the resist pattern to light.

[0094] The resist pattern formed by the resist pattern forming method according to this embodiment may be a resist pattern having space portions with an aspect ratio of 1.3 or more. The aspect ratio of the space portions may be 1.3 to 5.0. Here, the aspect ratio of the space portions means the value obtained by dividing the height of the space portions (thickness of the resist pattern) by the width of the space portions when the space portions are linear patterns, and means the value obtained by dividing the height of the space portions (thickness of the resist pattern) by the diameter of the space portions when the space portions are cylindrical. The photosensitive element according to this embodiment can form a resist pattern having space portions with such high aspect ratios.

[0095] The method for manufacturing a laminate according to this embodiment includes a conductor layer forming step of forming a resist pattern by the above-described resist pattern forming method, and then forming a conductor layer (e.g., a metal layer) on at least a portion of the portion of the substrate where the resist pattern is not formed.

[0096] In the conductor layer forming step, a conductor pattern (e.g., a wiring pattern) may be obtained as the conductor layer, and the method for manufacturing a laminate according to this embodiment may be a method for manufacturing (forming) a conductor pattern (e.g., a wiring pattern). Examples of materials constituting the conductor layer include copper, solder, nickel, and gold. The aspect ratio of the conductor layer may be 1.3 or more, and may be 1.3 to 5.0. When the conductor layer is a linear pattern, the aspect ratio of the conductor layer refers to the value obtained by dividing the thickness of the conductor layer by the width of the conductor layer, and when the conductor layer is cylindrical, the aspect ratio of the conductor layer refers to the value obtained by dividing the thickness of the conductor layer by the diameter of the conductor layer.

[0097] The conductor pattern may be a conductive coil of an inductor (such as a power inductor) or a copper pillar that forms a connection portion of a semiconductor device. The method for manufacturing a laminate according to this embodiment may be a method for manufacturing an inductor, a wiring board (such as a printed wiring board), a semiconductor device, or the like that includes such a conductor pattern.

[0098] In the conductor layer forming step, at least a portion of the portion of the substrate where the resist pattern is not formed may be plated to form a conductor layer. In the conductor layer forming step, the resist pattern may be used as a mask to plate at least a portion of the portion of the substrate where the resist pattern is not formed. When a laminate including a metal layer disposed on an insulating layer is used as the substrate, the metal layer exposed in the portion of the substrate where the resist pattern is not formed may be plated.

[0099] The plating process may be electrolytic plating or electroless plating, including copper plating such as copper sulfate plating and copper pyrophosphate plating, solder plating such as high-throw solder plating, nickel plating such as Watts bath (nickel sulfate-nickel chloride) plating and nickel sulfamate plating, and gold plating such as hard gold plating and soft gold plating.

[0100] The method for producing a laminate according to this embodiment may include a cured product removal step of removing at least a portion of the resist pattern after the conductor layer formation step. In the cured product removal step, a portion or all of the resist pattern may be removed.

[0101] The resist pattern can be stripped and removed, for example, with an aqueous solution that is more strongly alkaline than the aqueous alkaline solution used in the development step. Examples of such a strongly alkaline aqueous solution include a 1 to 10% by mass aqueous solution of sodium hydroxide and a 1 to 10% by mass aqueous solution of potassium hydroxide. Methods for removing the resist pattern include an immersion method and a spray method. The methods for removing the resist pattern may be used alone or in combination.

[0102] When a laminate including a metal layer disposed on an insulating layer is used as a substrate, the portion of the metal layer that was covered with the resist pattern is exposed in the cured product removal step. The laminate manufacturing method according to this embodiment may include a step of removing the exposed portion of the metal layer after the cured product removal step. The metal layer can be removed, for example, by etching.

[0103] FIG. 2 is a schematic cross-sectional view showing an example of a method for producing a laminate. First, as shown in Fig. 2(a), in the photosensitive layer forming step, a photosensitive layer 10 is formed on a substrate 20 using the photosensitive element 1 of Fig. 1. In the photosensitive layer forming step, for example, the photosensitive layer 1a of the photosensitive element 1 is laminated on the substrate 20 as the photosensitive layer 10, and then the support 1b is peeled off. The substrate 20 can be a laminate including a metal layer disposed on an insulating layer. Next, as shown in FIG. 2(b), in the exposure step, the photosensitive layer 10 is irradiated with actinic rays L to form a photocured portion. Next, as shown in FIG. 2(c), in the development step, the uncured portions of the photosensitive layer 10 are removed to form a resist pattern (cured product pattern) 10a. Next, as shown in (d) of Figure 2, in the conductor layer formation process, a plating process is performed using the resist pattern 10a as a mask to form a conductor layer (plating layer) 30 in the part of the base material 20 where the resist pattern 10a is not formed. Next, as shown in Fig. 2(e), in the cured product removal step, the resist pattern 10a is removed, thereby obtaining a laminate having a conductor layer 30 as a conductor pattern. [Example]

[0104] The present disclosure will be explained in more detail below using examples, but the present disclosure is not limited to these examples.

[0105] [Examples 1 to 3 and Comparative Examples 1 to 2] <Preparation of Photosensitive Resin Composition> The materials shown in Table 1 were mixed in the amounts (unit: parts by mass) shown in the table to prepare solutions of photosensitive resin compositions. The amounts (parts by mass) of components other than the solvent shown in Table 1 are the masses of non-volatile components (solid content). Details of each component shown in Table 1 are as follows.

[0106] ((A) Binder polymer) A-1: Ethylene glycol monomethyl ether / toluene solution (solid content: 45% by mass) of a copolymer of methacrylic acid / methyl methacrylate / styrene / benzyl methacrylate (mass ratio: 27 / 5 / 45 / 23, Mw: 47000, acid value: 176.1 mg KOH / g, Tg: 107°C) A-2: Ethylene glycol monomethyl ether / toluene solution (solid content: 45% by mass) of a copolymer of methacrylic acid / methyl methacrylate / ethyl acrylate / styrene / butyl methacrylate (mass ratio: 30 / 22 / 10 / 8 / 30, Mw: 50,000, acid value: 196 mg KOH / g, Tg: 95.6°C)

[0107] ((B) Photopolymerizable compound) FA-321M: 2,2-bis(4-(methacryloxypentaethoxy)phenyl)propane (manufactured by Showa Denko Materials Co., Ltd., number of EO groups: 10 (average value)) UA-11: Polyoxyethylene urethane dimethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) UA-13: Polyoxyethylene polyoxypropylene urethane dimethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) FA-023M: Polyalkylene glycol dimethacrylate (manufactured by Showa Denko Materials Co., Ltd., number of EO groups: 6 (average value), number of PO groups: 12 (average value)) FA-318A: Nonylphenoxy polyethylene glycol acrylate (Showa Denko Materials Co., Ltd.)

[0108] ((C) Photopolymerization initiator) B-CIM: 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole (Changzhou Power Electronic New Materials Co., Ltd.)

[0109] ((D) Coumarin-based sensitizers) Coumarin 102: 2,3,6,7-tetrahydro-9-methyl-1H,5H,11H-[1]benzopyrano[6,7,8-ij]quinolizin-11-one (Tokyo Chemical Industry Co., Ltd.)

[0110] (Other ingredients) EAB: 4,4'-bis(diethylamino)benzophenone (Hodogaya Chemical Co., Ltd.) (sensitizer) LCV: Leuco Crystal Violet (Yamada Chemical Co., Ltd.) (color former) Q-TBC-5P: 4-tert-butylcatechol (DIC Corporation) (polymerization inhibitor) MKG: Malachite Green (Osaka Organic Chemical Industry Co., Ltd.) (dye) SH-193: Leveling agent (manufactured by Toray Dow Corning Silicone Co., Ltd.)

[0111] (solvent) MAL: Methanol TLS: Toluene ACS: Acetone

[0112] <Preparation of Photosensitive Element> A solution of the photosensitive resin composition was uniformly applied to a PET film (support, thickness: 16 μm, manufactured by Toray Industries, Inc., product name: FB-40) and then dried using a hot air convection dryer at 70°C for 10 minutes and then at 100°C for 10 minutes to produce a photosensitive element having a photosensitive layer made of the photosensitive resin composition on one side of the PET film. The thickness of the photosensitive layer was measured at 10 points using a measuring device manufactured by Nikon Corporation (main body: product name "MH-15", measuring stage: product name "MS-5C"), and the average thickness was obtained. The average thickness of the photosensitive layer is shown in Table 1.

[0113] <Evaluation> (Preparation of laminate) A copper-clad laminate (manufactured by Showa Denko Materials Co., Ltd., product name "MCL-E-67") in which copper foil (thickness: 12 μm) was laminated on both sides of a glass fiber-reinforced epoxy resin layer was washed with water. Subsequently, it was pickled and washed with water, and then dried in an air stream. After heating this copper-clad laminate to 80°C, a photosensitive element was laminated onto the copper foil of the copper-clad laminate. The lamination was performed using a heat roll at 110°C, with a pressure of 0.4 MPa and a roll speed of 1.0 m / min. This resulted in a laminate in which the copper-clad laminate, photosensitive layer, and PET film were laminated in this order.

[0114] (Sensitivity evaluation) A phototool having a 41-step tablet with a density range of 0.00 to 2.00, density step of 0.05, tablet size of 20 mm x 187 mm, and each step size of 3 mm x 12 mm was placed on the PET film of the laminate as a negative mask. Next, using a parallel light exposure device (manufactured by Oak Manufacturing Co., Ltd., product name "EXM-1201") with a high-pressure mercury lamp as a light source, the photosensitive layer was exposed with an energy amount such that the number of remaining steps after development of the 41-step tablet was 14.0. The exposure dose at this time (unit: mJ / cm 2 The sensitivity (photosensitivity) was evaluated by the following method. The lower the exposure amount, the better the sensitivity. The results are shown in Table 1.

[0115] (resolution evaluation) A resolution evaluation mask was placed on the PET film of the laminate, which had (1) a rectangular coil pattern with a line width / space width of x / x (x: 10-100, unit: μm) and (2) a pattern of dots with diameters of 10-100 μm arranged in a grid pattern. The mask was then exposed to light with an energy level that resulted in a remaining step count of 14.0 after development of a 41-step tablet. After exposure, the PET film was peeled off, and the unexposed areas were removed by spraying a 1% by weight aqueous solution of sodium carbonate at 30°C for twice the shortest development time (the shortest time required to remove the unexposed areas). This formed a resist pattern.

[0116] (1) Regarding the square coil pattern, after development, the space portions (unexposed portions) were cleanly removed under an optical microscope, and the line portions (exposed portions) were formed without meandering, chipping, or collapse. The resolution (square coil pattern) was evaluated based on the smallest line width / space width value among the resist patterns. The smaller this value, the better the resolution (square coil pattern). The ratio of the resist pattern thickness to this resolution (aspect ratio: resist pattern thickness / resolution) was also calculated. The results are shown in Table 1. An electron microscope photograph of the square coil pattern (pattern with the smallest line width / space width) formed using the photosensitive element of Example 2 is shown in Figure 3.

[0117] (2) Regarding the dot pattern, after development, the formed via pattern (via hole pattern) was observed and evaluated using an optical microscope. The resolution (via pattern) was evaluated based on the value of the smallest via pattern diameter among the via patterns arranged in a grid pattern that were completely removed (opened). The smaller this value, the better the resolution (via pattern). In addition, the ratio of the resist pattern thickness to this resolution (aspect ratio: resist pattern thickness / resolution) was calculated. The results are shown in Table 1.

[0118] [Table 1] [Explanation of symbols]

[0119] 1...photosensitive element, 1a...photosensitive layer, 1b...support (support film), 10...photosensitive layer, 10a...resist pattern, 20...substrate, 30...conductor layer, L...actinic light.

Claims

1. Support and The support comprises a photosensitive layer formed on the support using a photosensitive resin composition containing a binder polymer, a photopolymerizable compound, a photopolymerization initiator, and a coumarin-based sensitizer represented by the following general formula (3) or (4), The photopolymerizable compound comprises a (meth)acrylate having one polymerizable ethylenically unsaturated bond within the molecule, The photopolymerization initiator comprises only a hexaarylbiimidazole derivative. The content of the photopolymerization initiator is 1 to 10 parts by mass per 100 parts by mass of the total amount of the binder polymer and the photopolymerizable compound. A photosensitive element having a photosensitive layer thickness of 30 μm or more. 【Chemistry 1】 [In the formula, Z1 and Z21 each independently represent a halogen atom, a C1-C20 alkyl group, a C3-C10 cycloalkyl group, a C6-C14 aryl group, an amino group, a C1-C10 alkylamino group, a C2-C20 dialkylamino group, a mercapto group, a C1-C10 alkylmercapto group, an allyl group, a C1-C20 hydroxyalkyl group, a carboxyl group, a C1-C10 carboxyalkyl group, a C1-C10 acyl group, a C1-C20 alkoxyl group, a C1-C20 alkoxycarbonyl group, or a group containing a heterocycle; Z11 and Z12 each independently represent a hydrogen atom or a C1-C20 alkyl group; r represents an integer from 0 to 3; and s represents an integer from 0 to 8. At least two of the r Z1, Z11, and Z12 may form a ring. ] 【Chemistry 2】 [In the formula, Z1, Z2, Z31, and Z32 each independently represent a halogen atom, a C1-C20 alkyl group, a C3-C10 cycloalkyl group, a C6-C14 aryl group, an amino group, a C1-C10 alkylamino group, a C2-C20 dialkylamino group, a mercapto group, a C1-C10 alkylmercapto group, an allyl group, a C1-C20 hydroxyalkyl group, a carboxyl group, a C1-C10 carboxyalkyl group, a C1-C10 acyl group, a C1-C20 alkoxyl group, a C1-C20 alkoxycarbonyl group, or a heterocyclic group; m represents an integer from 0 to 2, t represents an integer from 0 to 1, u represents an integer from 0 to 6, and v represents an integer from 0 to 6.]

2. The photosensitive element according to claim 1, wherein the binder polymer has benzyl (meth)acrylate as a monomer unit.

3. The photosensitive element according to claim 2, wherein the binder polymer contains benzyl (meth)acrylate in an amount of 10 to 60% by mass, based on the total amount of monomer units constituting the binder polymer.

4. The photosensitive element according to claim 1, wherein the binder polymer has styrene as a monomer unit.

5. The photosensitive element according to claim 4, wherein the styrene content in the binder polymer is 10 to 50% by mass, based on the total amount of monomer units constituting the binder polymer.

6. The photosensitive element according to claim 1, wherein the binder polymer has alkyl (meth)acrylate as a monomer unit.

7. The photosensitive element according to claim 6, wherein the binder polymer contains alkyl (meth)acrylate in an amount of 5 to 40% by mass, based on the total amount of monomer units constituting the binder polymer.

8. The photosensitive element according to claim 1, wherein the binder polymer has (meth)acrylic acid as a monomer unit.

9. The photosensitive element according to claim 8, wherein the binder polymer contains 10 to 40% by mass of (meth)acrylic acid, based on the total amount of monomer units constituting the binder polymer.

10. The photosensitive element according to claim 1, wherein the content of the coumarin-based sensitizer is 0.01 to 0.3 parts by mass per 100 parts by mass of the total amount of the binder polymer and the photopolymerizable compound.

11. The photosensitive element according to claim 1, wherein the content of the coumarin-based sensitizer is less than 0.05 parts by mass with respect to 100 parts by mass of the total amount of the binder polymer and the photopolymerizable compound.

12. The photosensitive element according to claim 1, wherein the content of a (meth)acrylate having one polymerizable ethylenically unsaturated bond in the molecule is 1 to 30% by mass based on the total amount of the photopolymerizable compound.

13. The photosensitive element according to claim 1, wherein the photopolymerizable compound includes urethane (meth)acrylate.

14. The photosensitive element according to claim 1, wherein the thickness of the photosensitive layer is 75 μm or more.

15. The photosensitive element according to claim 1, wherein the thickness of the photosensitive layer is greater than 100 μm.

16. A photosensitive element according to claim 1, for forming a resist pattern having a space portion with an aspect ratio of 1.3 or more.

17. A photosensitive element according to claim 1, for forming a conductive coil of an inductor.

18. A photosensitive element according to claim 1, for forming a copper pillar for semiconductor connection.

19. A step of providing a photosensitive layer on a substrate using a photosensitive element described in any one of claims 1 to 18, The steps include irradiating at least a portion of the photosensitive layer with active light to form a photocured portion, A step of removing at least a portion of the photosensitive layer other than the photocured portion to form a resist pattern, A method for forming a resist pattern, comprising the following features.

20. The method for forming a resist pattern according to claim 19, wherein the resist pattern has a space portion having an aspect ratio of 1.3 or more.

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