Photosensitive paste, method for forming wiring patterns, method for manufacturing electronic components, and electronic components

Abstract

The objective is to provide a photosensitive paste capable of forming a desired shape with high precision, a method for forming a wiring pattern using the above-mentioned photosensitive paste, a method for manufacturing an electronic component, and an electronic component itself. [Solution] A photosensitive paste comprising a photopolymerization initiator, a photopolymerizable monomer, an alkali-soluble polymer, an inorganic powder, and a radical scavenger. A method for forming a wiring pattern, comprising the steps of: applying the above conductive photosensitive paste onto an insulating sheet to form a photosensitive paste film; irradiating a part of the photosensitive paste film with active energy rays; and removing the uncured portion of the photosensitive paste film to form a wiring pattern.

Description

Technical Field

[0001] The present invention relates to a photosensitive paste, a method for forming a wiring pattern, a method for manufacturing an electronic component, and an electronic component.

Background Art

[0002] A photosensitive paste usually contains a photopolymerizable monomer and a photoinitiator (for example, Patent Document 1). When the photosensitive paste is irradiated with active energy rays, the photoinitiator generates radicals. The radicals quickly add to the photopolymerizable monomer to generate monomer radicals. Thereby, the polymerization reaction is initiated. Monomer radicals are continuously generated, and eventually, a polymer (cured product) derived from the photopolymerizable monomer is formed.

[0003] When forming a wiring pattern using a photosensitive paste, after applying the photosensitive paste to an insulating layer, a part of it is irradiated with active energy rays. The photopolymerizable monomer contained in the exposed part of the photosensitive paste polymerizes and cures. Subsequently, the remaining part of the photosensitive paste that remains uncured is removed. Thereby, a predetermined wiring pattern is formed on the insulating layer.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the monomer radicals spread and are generated not only in the part irradiated with the active energy rays, and the polymerization reaction can proceed. In this case, a wiring pattern thicker than desired is formed.

[0006] This disclosure aims to provide a photosensitive paste capable of forming a desired shape with high precision. This disclosure further aims to provide a method for forming a wiring pattern using the above-mentioned photosensitive paste, a method for manufacturing an electronic component, and an electronic component. [Means for solving the problem]

[0007] To solve the aforementioned problems, a photosensitive paste, which is one aspect of this disclosure, Photopolymerization initiator and Photopolymerizable monomers, Alkali-soluble polymers and Inorganic powder and It contains a radical scavenger.

[0008] According to the above embodiment, when patterning using a photosensitive paste, the diffusion of monomer radicals in the in-plane direction of the coated surface of the photosensitive paste is suppressed, so that a desired shape can be formed with high precision.

[0009] A method for forming a wiring pattern, according to one aspect of this disclosure, The process involves applying the above-mentioned conductive photosensitive paste onto an insulating sheet to form a photosensitive paste film, A step of irradiating a portion of the photosensitive paste film with active energy rays, The process includes a step of removing the uncured portion of the photosensitive paste film to form a wiring pattern.

[0010] According to the above embodiment, a wiring pattern having a desired shape can be obtained.

[0011] A method for manufacturing an electronic component, which is one aspect of this disclosure, The process involves applying the above-mentioned photosensitive conductive paste onto an insulating sheet to form a photosensitive paste film, A step of irradiating a portion of the photosensitive paste film with active energy rays, The process involves removing the uncured portion of the photosensitive paste film to form a wiring pattern, A step of laminating insulating sheets onto the aforementioned wiring pattern, The process includes firing the wiring pattern and the insulating sheet to obtain a plurality of insulating layers as a sintered body of the plurality of insulating sheets, and internal wiring as a sintered body of the wiring pattern.

[0012] According to the above embodiment, an electronic component having high-precision internal wiring can be obtained.

[0013] An electronic component that is one aspect of this disclosure is A substrate containing multiple insulating layers, The present invention comprises an internal wiring, which is provided inside the aforementioned base body and is a sintered body of the photosensitive paste described in claim 2, which has been hardened.

[0014] According to the above embodiment, an electronic component with excellent performance and reliability can be obtained. [Effects of the Invention]

[0015] The photosensitive paste of the present invention allows for the formation of desired shapes with high precision. Furthermore, electronic components obtained using the photosensitive paste of the present invention exhibit superior performance and reliability. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic perspective view showing electronic components. [Figure 2] This is a schematic exploded perspective view showing electronic components. [Modes for carrying out the invention]

[0017] Hereinafter, a photosensitive conductive paste, a method for forming a wiring pattern, a method for manufacturing an electronic component, and an electronic component, which are embodiments of this disclosure, will be described in detail with reference to the illustrated embodiments. Note that some of the drawings are schematic and may not reflect actual dimensions or proportions.

[0018] [First Embodiment] (Electronic components) Figure 1 is a schematic perspective view showing an electronic component. Figure 2 is a schematic exploded perspective view showing an electronic component. In Figure 1, the components are depicted transparently to facilitate understanding of their structure, but they may also be semi-transparent or opaque. In Figure 1, the coil is omitted to facilitate understanding of the structure. In Figure 2, the external electrodes are omitted for clarity.

[0019] In the following explanation, a multilayer coil component will be used as an example of an electronic component, but the electronic components of this disclosure are not limited to this and can be applied to various electronic components such as capacitor components and LC composite components.

[0020] As shown in Figures 1 and 2, the laminated coil component 10 comprises a base body 4, a coil 5 provided inside the base body 4, and a first external electrode 6a and a second external electrode 6b provided on the base body 4.

[0021] The shape of the base body 4 is not particularly limited, and in this embodiment it is substantially rectangular parallelepiped. The outer surface of the base body 4 has a first end face 41, a second end face 42 opposite the first end face 41, a first side surface 43 connecting the first end face 41 and the second end face 42, a second side surface 44 opposite the first side surface 43, a bottom surface 45 connecting the first end face 41, the second end face 42, the first side surface 43 and the second side surface 44, and a top surface 46 opposite the bottom surface 45 and connecting the first end face 41, the second end face 42, the first side surface 43 and the second side surface 44. The direction from the first end face 41 toward the second end face 42 is defined as the X direction, the direction from the first side surface 43 toward the second side surface 44 is defined as the Y direction, and the direction from the bottom surface 45 toward the top surface 46 is defined as the Z direction. In this specification, the Z direction may be referred to as the upper side.

[0022] The base body 4 is constructed by laminating multiple insulating layers 40. Each insulating layer 40 corresponds to an example of a sintered "insulating sheet" as described in the claims. The material of the insulating sheet is not particularly limited and includes, for example, borosilicate glass and inorganic powder. The lamination direction of the insulating layers 40 is parallel to the Z direction. That is, the insulating layers 40 are layered and spread in the XY plane. "Parallel" is not limited to a strictly parallel relationship, but also includes a substantially parallel relationship, taking into account the range of realistic variations. Due to firing or other processes, the interfaces between the multiple insulating layers 40 in the base body 4 may not be clearly defined.

[0023] The coil 5 comprises a plurality of coil wirings 2 stacked along the axial direction, and via wirings (not shown) extending along the axial direction and connecting adjacent coil wirings 2 in the axial direction. The plurality of coil wirings 2 are each wound along a plane, arranged side by side in the axial direction, and electrically connected in series to form a helix. The coil wirings 2 are formed using a conductive photosensitive paste (photosensitive conductive paste). The coil wirings 2 correspond to an example of the "internal wiring" described in the claims. The coil wirings 2 and the "internal wiring" correspond to an example of the "wiring pattern" described in the claims or a sintered body of a hardened conductive "photosensitive paste".

[0024] Coil 5 is formed in a rectangular shape when viewed from the axial direction, but is not limited to this shape. The shape of coil 5 may be, for example, circular, elliptical, rectangular, or other polygonal. Also, coil 5 has its axial direction parallel to the Z direction and is wound along the axial direction. The axis of coil 5 refers to the central axis of the spiral shape of coil 5.

[0025] The coil 5 is wound spirally along the lamination direction of the insulating layer 40. The first end 5a of the coil 5 is exposed from the first end face 41 of the base body 4 and connected to the first external electrode 6a. The second end 5b of the coil 5 is exposed from the second end face 42 of the base body 4 and connected to the second external electrode 6b.

[0026] The coil wiring 2 is formed by winding it on the main surface (XY plane) of the insulating layer 40, which is perpendicular to the axial direction. The number of turns of the coil wiring 2 is less than one, but may be one or more. The via wiring is provided in the via holes 3 of the insulating layer 40 and penetrates the insulating layer 40 in the thickness direction (Z direction). Adjacent coil wirings 2 in the stacking direction are electrically connected in series via the via wiring.

[0027] The insulating layer 40 located between adjacent coil wirings 2 has via holes 3 at the positions where the adjacent coil wirings 2 are connected. The via holes 3 penetrate the insulating layer 40 in the thickness direction (Z direction).

[0028] A laminated coil component 10 comprising a base body 4 and a coil 5 provided within the base body 4 is obtained by a method that includes forming a wiring pattern by photolithography using a photosensitive paste. First, a photosensitive conductive paste is applied onto an insulating sheet to form a photosensitive paste film. After irradiating a part of the photosensitive paste film with active energy rays, the uncured portion of the photosensitive paste film is removed (developed) to form a wiring pattern. An insulating sheet is then laminated again on the wiring pattern. In this way, a laminated structure is obtained by alternately laminating multiple layers of insulating sheets and wiring patterns made of photosensitive conductive paste. Finally, by firing the laminated structure, a base body 4 containing multiple insulating layers 40 as sintered bodies of insulating sheets, and a coil 5 provided inside the base body 4 and containing multiple coil wirings 2 as sintered bodies of wiring patterns are obtained.

[0029] The first external electrode 6a and the second external electrode 6b are made of a conductive material such as Ag, Cu, Au, or alloys mainly composed of these materials. In this embodiment, the first external electrode 6a is provided continuously on the entire surface of the first end face 41 of the base body 4, the end of the first side surface 43 on the first end face 41 side, the end of the second side surface 44 on the first end face 41 side, the end of the bottom surface 45 on the first end face 41 side, and the end of the top surface 46 on the first end face 41 side. The second external electrode 6b is provided continuously on the entire surface of the second end face 42 of the base body 4, the end of the first side surface 43 on the second end face 42 side, the end of the second side surface 44 on the second end face 42 side, the end of the bottom surface 45 on the second end face 42 side, and the end of the top surface 46 on the second end face 42 side. In short, each of the first external electrode 6a and the second external electrode 6b is a five-sided electrode. However, the invention is not limited to this, and the first external electrode 6a may be, for example, an L-shaped electrode provided continuously on a part of the first end face 41 and a part of the bottom face 45. Similarly, the second external electrode 6b may be, for example, an L-shaped electrode provided continuously on a part of the second end face 42 and a part of the bottom face 45.

[0030] (Photosensitive paste) Next, the detailed configuration of the photosensitive conductive paste used to form the coil 5 will be described. The photosensitive conductive paste refers to a photosensitive paste that has conductivity. The photosensitive paste according to this disclosure is not limited to conductive and may be non-conductive.

[0031] The photosensitive paste according to this disclosure comprises a photopolymerization initiator, a photopolymerizable monomer, an alkali-soluble polymer, an inorganic powder, and a radical scavenger. The photosensitive paste according to this disclosure is a negative type containing a monomer polymerized by active energy rays. Hereinafter, the components obtained by removing the inorganic powder and radical scavenger from the photosensitive paste may be referred to as a photosensitive resin composition.

[0032] When forming a wiring pattern on an insulating sheet using photolithography, the radical scavenger suppresses the excessive diffusion of monomer radicals, particularly along the main surface direction of the insulating sheet. As a result, the desired wiring pattern is formed with high precision, and the coil wiring 2 obtained by firing it is also formed with high precision. Hereinafter, the formation of a desired shape with high precision by photolithography may be referred to as having excellent resolution.

[0033] Hereinafter, "hydrocarbon group" refers to a group containing carbon and hydrogen, obtained by removing one hydrogen atom from a hydrocarbon. Examples of hydrocarbon groups include aliphatic hydrocarbon groups and aromatic hydrocarbon groups having 1 to 20 carbon atoms. Aliphatic hydrocarbon groups may be linear, branched, or cyclic, and may be saturated or unsaturated. A hydrocarbon group may contain one or more ring structures. Typical examples of hydrocarbon groups include alkyl groups, alkoxy groups, alkenyl groups, alkynyl groups, cycloalkyl groups, unsaturated cycloalkyl groups, heterocyclyl groups, and unsaturated heterocyclyl groups.

[0034] The hydrocarbon group may have one or more N, O, S, Si, amide bonds, carbonyl structures (-C(=O)-), or carbonyloxy structures (-OC(=O)-) at its terminal or in its molecular chain.

[0035] One or more hydrogen atoms of a hydrocarbon group may be substituted by substituents. Examples of substituents include halogen atoms, carboxyl groups, amino groups, C1-C6 alkyl groups, C1-C6 alkoxy groups, C2-C6 alkenyl groups, C2-C6 alkynyl groups, C3-C10 cycloalkyl groups, C3-C10 unsaturated cycloalkyl groups, 5-C10 heterocyclyl groups, 5-C10 unsaturated heterocyclyl groups, C3-C10 aryl groups, and 5-C10 heteroaryl groups. The substituents may be located on the side chains or at the terminals of the hydrocarbon group.

[0036] Examples of halogen atoms include fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).

[0037] Examples of alkyl groups having 1 to 6 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, n-pentyl, neopentyl, isopentyl, 3-pentyl, n-hexyl, and isohexyl groups.

[0038] Examples of alkoxy groups having 1 to 6 carbon atoms include methoxy, ethoxy, propoxy, isopropoxy, butoxy, pentyloxy, hexyloxy groups, and their isomers.

[0039] The amino group may be primary (-NH2) or secondary (-NH2) N ) is acceptable, Grade 3 (-NR N R N ') is acceptable. N N and N N ' are, for example, alkyl groups, each independently having 1 to 6 carbon atoms.

[0040] <Radical scavenger> Radical scavengers efficiently trap alkyl radicals (R·) and peroxy radicals (ROO·) generated by irradiation with active energy rays. Radical scavengers are also known as polymerization inhibitors, light stabilizers, and antioxidants.

[0041] The radical scavenger content may be 0.01% by mass or more of the photosensitive paste, or 0.1% by mass or more. The radical scavenger content may be 5% by mass or less of the photosensitive paste, or 1% by mass or less. In one embodiment, the radical scavenger content is 0.01% by mass or more and 5% by mass or less of the photosensitive paste.

[0042] The radical scavenger is not particularly limited as long as it is a compound capable of trapping radicals. Examples of the radical scavenger include at least one selected from the group consisting of a radical scavenger having a phenol structure, a radical scavenger having a benzotriazole structure, and a radical scavenger having a hindered amine structure.

[0043] In this embodiment, the radical scavenger has a phenol structure. By using a radical scavenger having a phenol structure (hereinafter referred to as a phenolic radical scavenger), inorganic powder is more easily removed together with an uncured photopolymerizable monomer or the like during development.

[0044] ≪Phenolic radical scavenger≫ The phenol structure has a benzene ring and at least one hydroxyl group bonded to the benzene ring. There may be one or more phenol structures in one molecule, and there may be two or more. The plurality of phenol structures may be the same or different.

[0045] The phenolic radical scavenger is, for example, represented by the following general formula:

Chemical formula

[0046] R a is bonded to the benzene ring by one or more, and may be bonded by two or more. R a is bonded to the benzene ring by five or less, and may be bonded by four or less. The plurality of R a may be of the same kind or different kinds.

[0047] At least one R aThis may be a hydroxyl group. In other words, the phenolic radical scavenger may have two or more hydroxyl groups bonded to the benzene ring.

[0048] R a This is an alkyl ester group (-C(=O)OR a1 ) may have R a1 For example, this is an alkyl group having 1 to 20 carbon atoms. The alkyl ester group may be directly bonded to the benzene ring, or it may be bonded to the benzene ring via an alkyl group having 1 to 6 carbon atoms, for example.

[0049] R a is a thioalkyl group (-SR a2 ) may have R a2 For example, this is an alkyl group having 1 to 20 carbon atoms. The thioalkyl group may be directly bonded to the benzene ring, or it may be bonded to the benzene ring via an alkyl group having 1 to 6 carbon atoms, for example.

[0050] at least one R a R may be a hydrocarbon group. a R may be an alkoxy group, a carbon-1 to carbon-6 alkoxy group, or a methoxy group. a This group may be an alkyl group, a C1-C6 alkyl group, or a tert-butyl group. A phenolic radical scavenger having at least one tert-butyl group is also called a hindered phenol.

[0051] Hindered phenols are, for example, those with the following general formula: [ka] (In the formula, R a (This is synonymous with the above.) It is represented as follows.

[0052] Examples of phenolic radical scavengers include phenol, catechol, pyrogallol, 1,2,4-trihydroxybenzene, phloroglucinol, resorcinol, homocatechol, p-cresol, 2,4-dimethylphenol, 2,6-dimethylphenol, 4,6-bis(dodecylthiomethyl)-o-cresol, and 4,6-bis(octylthiomethyl)-o-cresol.

[0053] Examples of phenolic radical scavengers having an alkoxy group include 2-methoxyphenol, 4-methoxyphenol, and 2,6-dimethoxyphenol.

[0054] Examples of hindered phenols include 2,6-di-tert-butyl-4-methylphenol, 2,5-di-tert-butylbenzene-1,4-diol, tert-butylhydroxyanisole, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], and 3,3',3'',5,5',5''-hexa-tert-butyl-a,a',a''-(methicin Examples include len-2,4,6-triyl)tri-p-cresol, ethylenebis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,3,5-tris[(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)methyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, and 2,6-di-tert-butyl-4-[4,6-bis(octylthio)-1,3,5-triazine2-ylamino]phenol.

[0055] <Photopolymerization initiator> Photopolymerization initiators generate highly reactive radicals using active energy rays. These radicals attach to photopolymerizable monomers, triggering the initiation reaction of the photopolymerizable monomers. Radicals are generated in a chain reaction, eventually leading to the formation of polymers derived from the photopolymerizable monomers.

[0056] The content of the photopolymerization initiator may be 1% by mass or more, and may be 2% by mass or more, of the photosensitive resin composition. The content of the photopolymerization initiator may be 10% by mass or less, and may be 5% by mass or less, of the photosensitive resin composition. In one embodiment, the content of the photopolymerization initiator is 1% by mass or more, and 10% by mass or less, of the photosensitive resin composition.

[0057] Examples of photopolymerization initiators include at least one selected from the group consisting of benzoin or benzoin ether compounds, alkylphenone compounds, benzophenone compounds, oxime ester compounds, acylphosphine oxide compounds, and α-ketoester compounds.

[0058] Examples of benzoin or benzoin ether-based photopolymerization initiators include benzoin, benzoin ethyl ether, benzoin isopropyl ether, benzoin phenyl ether, methyl benzoin, ethyl benzoin, and benzyl dimethyl ketal.

[0059] Examples of alkylphenone-based photopolymerization initiators include α-hydroxyalkylphenone compounds and α-aminoalkylphenone compounds. Examples of α-aminoalkylphenone compounds include 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, and 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one. α-hydroxyalkylphenone compounds include, specifically, 2-hydroxy-2-methylpropiophenone, diethoxyacetophenone, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-hydroxy-cyclohexyl-phenylketone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one, and 1-[4-(2-hydroxyethylphenyl] Examples include toxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]phenyl}-2-methylpropan-1-one, 1,1'-(oxybis(4,1-phenylene))bis(2-hydroxy)-2-methylpropan-1-one, 2,2-dimethoxy-2-phenylacetophenone, oligo{2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propane}, and 4-(2-acryloyl-oxyethoxy)phenyl-2-hydroxy-2-propyl ketone.

[0060] Examples of benzophenone-based photopolymerization initiators include benzophenone, methylbenzophenone, benzoylbenzoic acid, methyl o-benzoylbenzoate, 2-n-butoxy-4-dimethylaminobenzoate, 2-dimethylaminoethylbenzoate, ethyl p-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, 4-phenylbenzophenone, 4,4'-bisdiethylaminobenzophenone, 3,3'-dimethyl-4-methoxybenzophenone, (1-[4-(4-benzoylphenylsulfanyl)phenyl]-2-methyl-2-(4-methylphenylsulfonyl)propan-1-one, 4-(4-methylphenichio)benzophenone, methyl-o-benzoylbenzoate, 4,4'-dichlorobenzophenone, hydroxy Examples include benzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, acrylic benzophenone, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, 3,3'-dimethyl-4-methoxybenzophenone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, and other thioxanthone derivatives, Michler ketone, 4,4'-bis-diethylaminobenzophenone, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, and benzophenone derivative polymers.

[0061] Examples of oxime ester-based photopolymerization initiators include 1,2-octanedione, 1-[4-(phenylthio)phenyl]-,2-(O-benzoyl oxime), 1-phenyl-1,2-propanedione-2-(o-ethoxycarbonyl)oxime, ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-,1-(O-acetyloxime), and the like.

[0062] Examples of acylphosphine oxide-based photopolymerization initiators include 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, and ethyl(2,4,6-trimethylbenzoyl)-phenylphosphine.

[0063] Examples of α-ketoester-based photopolymerization initiators include methylbenzoyl formate, 2-(2-oxo-2-phenylacetoxyethoxy)ethyl ester of oxyphenylacetic acid, and 2-(2-hydroxyethoxy)ethyl ester of oxyphenylacetic acid.

[0064] The photopolymerization initiator may be an alkylphenone compound, an α-aminoalkylphenone compound, or 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one.

[0065] <Photopolymerizable monomers> Photopolymerizable monomers react with photopolymerization initiators to generate monomer radicals. These monomer radicals polymerize to produce polymers.

[0066] The content of the photopolymerizable monomer may be 5% by mass or more, and may be 10% by mass or more, of the photosensitive resin composition. The content of the photopolymerizable monomer may be 35% by mass or less, and may be 25% by mass or less, of the photosensitive resin composition. In one embodiment, the content of the photopolymerizable monomer is 5% by mass or more, and 35% by mass or less, of the photosensitive resin composition.

[0067] Photopolymerizable monomers are not limited in that they have at least one radical reactive group. Examples of radical reactive groups include at least one selected from the group consisting of acrylamide, acryloyl, methacryloyl, allyl, vinyl, styryl, and mercapto groups. Photopolymerizable monomers may have at least one (meth)acryloyl group as a radical reactive group. "(meth)acryloyl group" represents an acryloyl group and / or a methacryloyl group.

[0068] Photopolymerizable monomers having a (meth)acryloyl group include monofunctional (meth)acrylate monomers such as stearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, lauryl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, isodecyl (meth)acrylate, isooctyl (meth)acrylate, tridecyl (meth)acrylate, caprolactone (meth)acrylate, and ethoxylated nonylphenol (meth)acrylate; tripropylene glycol di(meth)acrylate and isocyanuric acid EO modified. Difunctional (meth)acrylate monomers such as diacrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, propoxylated neopentyl glycol di(meth)acrylate; glycerin tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ethoxylated trimethylol Trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, propoxylated glyceryl tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, ethoxylated pentaerythritol tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, caprolactone modified tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, hexanediol tri(meth)acrylate Trifunctional (meth)acrylate monomers such as tripropylene glycol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, and EO-modified trimethylolpropane tri(meth)acrylate; tetrafunctional (meth)acrylate monomers such as pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, tripentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and ethoxylated pentaerythritol tetra(meth)acrylate;Examples include pentafunctional (meth)acrylate monomers such as dipentaerythritol penta(meth)acrylate, tripentaerythritol penta(meth)acrylate, and dipentaerythritol monohydroxypenta(meth)acrylate; hexafunctional (meth)acrylate monomers such as dipentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, and tripentaerythritol hexa(meth)acrylate; and heptafunctional (meth)acrylate monomers with seven or more functions, such as tripentaerythritol hepta(meth)acrylate and tripentaerythritol octa(meth)acrylate.

[0069] The photopolymerizable monomer may be a trifunctional or more (meth)acrylate monomer, a tetrafunctional or more (meth)acrylate monomer, or a pentafunctional or more (meth)acrylate monomer. The photopolymerizable monomer may be dipentaerythritol monohydroxypenta(meth)acrylate.

[0070] <Alkali-soluble polymer> Alkali-soluble polymers are neutralized and solubilized by basic compounds. Alkali-soluble polymers are removed, for example, during developing processes using alkaline chemicals, along with uncured photopolymerizable monomers and inorganic powders. On the other hand, when photopolymerizable monomers polymerize due to active energy rays, nearby alkali-soluble polymers form a film together with the photopolymerized monomers, forming part of the wiring pattern. This can improve the adhesion of the wiring pattern to the insulating sheet.

[0071] The alkali-soluble polymer content may be 0.5% by mass or more of the photosensitive resin composition, and may be 2% by mass or more. The alkali-soluble polymer content may be 50% by mass or less of the photosensitive resin composition, and may be 40% by mass or less. In one embodiment, the alkali-soluble polymer content is 0.5% by mass or more and 50% by mass or less of the photosensitive resin composition.

[0072] Alkali-soluble polymers have at least one acidic group in their side chains. Typical examples of acidic groups include carboxyl groups. Alkali-soluble polymers include a main chain containing, for example, at least one of the following: carbon-carbon bonds, ether bonds, urea bonds, ester bonds, and urethane bonds. From the viewpoint of transparency, the main chain of an alkali-soluble polymer may contain a polymer chain having carbon-carbon bonds.

[0073] Alkali-soluble polymers containing polymer chains having at least one carboxyl group in the side chain and a carbon-carbon bond as the main chain can be obtained, for example, by copolymerization of an ethylenically unsaturated carboxylic acid and an ethylenically unsaturated compound. Typical examples of alkali-soluble polymers include carboxyl group-containing acrylic polymers.

[0074] Examples of ethylenically unsaturated carboxylic acids include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, vinylacetic acid, and their dimers and anhydrides.

[0075] Examples of ethylenically unsaturated compounds include acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, and isoboronyl acrylate; methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, and isoboronyl methacrylate; fumarate esters such as monoethyl fumarate; and styrene.

[0076] The carboxyl groups of the alkali-soluble polymer may be introduced after the main chain has been formed. For example, the carboxyl groups of the alkali-soluble polymer may be introduced by reacting a compound having epoxy groups in the side chains with an unsaturated monocarboxylic acid, and then further reacting it with a saturated or unsaturated polycarboxylic acid anhydride.

[0077] The alkali-soluble polymer may have unsaturated bonds. In this case, the alkali-soluble polymer also functions as a polymerization component, which can further improve the adhesion of the wiring pattern to the insulating sheet. The unsaturated bonds in the alkali-soluble polymer may be introduced, for example, by adding a monomer that is reactive with the carboxyl group in the side chain and has a polymerizable functional group (typically an epoxy group).

[0078] The weight-average molecular weight (Mw) of the alkali-soluble polymer may be between 10,000 and 50,000. The acid value of the alkali-soluble polymer may be between 30 and 150.

[0079] <Inorganic powder> Inorganic powders suppress the shrinkage of wiring patterns during the irradiation process with active energy rays, and furthermore, during the firing process. Inorganic powders can also impart various functions to photosensitive pastes. For example, the photosensitive conductive paste used to form coil 5 contains conductive inorganic powder (typically, metal powder described later), which makes the photosensitive paste conductive.

[0080] The inorganic powder content may be 68% by mass or more, and may be 72% by mass or more, of the photosensitive paste. The inorganic powder content may be 88% by mass or less, and may be 85% by mass or less, of the photosensitive paste. In one embodiment, the inorganic powder content is 68% by mass or more, and 88% by mass or less, of the photosensitive paste.

[0081] The average particle size of the inorganic powder is not particularly limited. The average particle size of the inorganic powder may be 5.0 μm or less, as long as fine wiring can be formed. The average particle size of the inorganic powder may be 1.0 μm or more.

[0082] The average particle size of inorganic powder is obtained as the median value (D50) based on volume from the particle size distribution in the range of 0.02 μm to 1400 μm, obtained by laser diffraction and scattering using a particle size distribution analyzer (e.g., Bell Microtrac MT3300-EX).

[0083] Inorganic powder can be rephrased as "particles that do not contain carbon atoms (C)." Inorganic powder is not particularly limited and can be appropriately selected depending on the purpose. Examples of inorganic powder include at least one selected from the group consisting of metal powder, glass powder, and ceramic powder.

[0084] Examples of metal powder materials include silver (Ag), copper (Cu), gold (Au), platinum (Pt), lead (Pd), nickel (Ni), tungsten (W), aluminum (Al), and molybdenum (Mo). These can be used individually or in combination of two or more. In particular, the metal powder may be Ag powder or Cu powder.

[0085] Examples of glass powder materials include known glasses such as borosilicate glass. Specifically, examples of glass powder materials include SiO2-PbO, SiO2-ZnO, SiO2-Bi2O3, SiO2-K2O, SiO2-Na2O, SiO2-PbO-B2O3, SiO2-ZnO-B2O3, SiO2-Bi2O3-B2O3, SiO2-K2O-B2O3, and SiO2-Na2O-B2O3 glass.

[0086] Examples of materials for ceramic powder include metal oxides, borides, nitrides, and silicides. Examples of metals include those exemplified as materials for metal powder. The ceramic powder may be a ferrite powder composed of two or more metal oxides, or a composite system with glass.

[0087] <Metal Resinate> The photosensitive paste relating to this disclosure may contain a metal resinate. The metal resinate is obtained by a reaction between a metal and an organic substance. The metal resinate can suppress delamination between the wiring pattern and the insulating sheet during the firing process.

[0088] The content of the metal resinate may be 0.01% by mass or more of the photosensitive resin composition, or 0.1% by mass or more. The content of the metal resinate may be 10% by mass or less of the photosensitive resin composition, or 5% by mass or less. In one embodiment, the content of the metal resinate is 0.01% by mass or more and 10% by mass or less of the photosensitive resin composition.

[0089] The metals contained in the metal resinate may have a higher melting point than the inorganic powder. Examples of metals that can be contained in the metal resinate include rhodium (Rh), nickel (Ni), Cu, manganese (Mn), and zirconium (Zr).

[0090] Examples of metal resinates include octylates, naphthenates, 2-ethylhexanoates, sulfonates, mercaptiates, and alkoxides of the above-mentioned metals.

[0091] <Solvent> The photosensitive paste according to this disclosure may contain a solvent. Examples of solvents include glycol-based organic solvents such as ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monoethylhexyl ether, propylene glycol monobutyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, and propylene glycol monophenyl ether.

[0092] <Other> The photosensitive paste relating to this disclosure may contain various additives. Examples of additives include sensitizers, defoamers, dispersants, and anti-settling agents.

[0093] (Method for forming wiring patterns) Next, we will explain how to form the wiring pattern. The wiring pattern is formed by a method comprising the steps of: applying the above-mentioned photosensitive conductive paste onto an insulating sheet to form a photosensitive paste film; irradiating a portion of the photosensitive conductive paste film with active energy rays; and removing the uncured portion of the photosensitive conductive paste film to form a wiring pattern.

[0094] (1) Preparation of insulating sheet First, prepare the insulating sheet. The insulating sheet is manufactured, for example, as follows: An insulating paste (hereinafter referred to as insulating paste) is screen printed over the entire surface of a support film such as a PET film and dried. If necessary, this printing and drying cycle is repeated several times. In this way, an insulating sheet with a predetermined thickness (for example, about 100 μm) is obtained.

[0095] Insulating paste typically contains insulating inorganic powder. Typical insulating inorganic powders include glass powder and ceramic powder. The glass powder contained in the insulating paste may be an SiO2-K2O-B2O3 system glass containing SiO2, K2O, and B2O3 in predetermined proportions. Two or more types of glass powder may be used. The average particle size of the glass powder is not particularly limited, for example, 0.8 μm to 1.3 μm.

[0096] The ceramic powder contained in the insulating paste may be a metal oxide or aluminum oxide. Two or more types of ceramic powder may be used. The average particle size of the ceramic powder is not particularly limited and may be, for example, 0.1 μm or more and 5.0 μm or less.

[0097] The insulating sheet may be manufactured by laminating pre-formed green sheets.

[0098] (2) Formation of a photosensitive paste film The photosensitive conductive paste of this disclosure is screen printed onto an insulating sheet and dried. This yields a photosensitive paste film. The thickness of the photosensitive paste film is not particularly limited and may be, for example, 5 μm or more and 10 μm or less.

[0099] (3) Irradiation with activated energy rays A portion of the photosensitive paste film is irradiated with active energy rays. A mask with an opening is used at this time. The mask partially blocks the active energy rays. Examples of active energy rays include visible light, ultraviolet light, infrared light, X-rays, alpha rays, beta rays, gamma rays, and electron beams. Among these, ultraviolet light may be used, and ultraviolet light having a peak wavelength between 350 nm and 420 nm may be used.

[0100] The integrated light intensity of the active energy rays is set appropriately according to the type and amount of photopolymerizable monomers and photopolymerization initiators, the thickness of the photosensitive paste film, etc. For example, the integrated light intensity of the active energy rays is 100 mJ / cm². 2 More than 2000mJ / cm 2 The following is acceptable:

[0101] (4) Removal of uncured portions of the photosensitive paste film Finally, the uncured portion of the photosensitive paste film is removed. This forms a wiring pattern consisting of cured photosensitive conductive paste. The wiring pattern formed by the photosensitive conductive paste according to this disclosure has excellent resolution.

[0102] Alkaline agents are used to remove uncured portions of the photosensitive paste film. This solubilizes the alkali-soluble polymer, which, along with other components (uncured photopolymerizable monomers, polymerization initiators, inorganic powders, etc.), is removed from the insulating sheet.

[0103] (Method of manufacturing electronic components) Next, a method for manufacturing the laminated coil component 10 will be described. The laminated coil component 10 is manufactured by a method comprising the steps of: applying the above-mentioned photosensitive conductive paste onto an insulating sheet to form a photosensitive paste film; irradiating a part of the photosensitive paste film with active energy rays; removing the uncured portion of the photosensitive paste film to form a wiring pattern; laminating an insulating sheet on the wiring pattern; and firing the wiring pattern and the insulating sheet to obtain a plurality of insulating layers 40 as a sintered body of a plurality of insulating sheets, and a coil wiring 2 as a sintered body of the wiring pattern (cured photosensitive conductive paste).

[0104] The process for forming the wiring pattern is carried out in the same manner as described above: (1) preparation of the insulating sheet, (2) formation of the photosensitive paste film, (3) irradiation with active energy rays, and (4) removal of the uncured portion of the photosensitive paste film. In the manufacturing method of the laminated coil component 10, this series of steps (1) to (4) for forming the wiring pattern is performed in multiple cycles.

[0105] In the second cycle, the (1) insulating sheet is fabricated as described above, not on the support film, but on the wiring pattern formed in the first cycle. This results in the lamination of the second layer of insulating sheet. Via holes 3 are formed at predetermined locations on this second layer of insulating sheet by laser irradiation.

[0106] Next, (2) a photosensitive paste film is formed, (3) active energy rays are irradiated, and (4) any uncured portions of the photosensitive paste film are removed to form the second layer of wiring pattern.

[0107] (1) fabrication of an insulating sheet, formation of via holes 3, (2) formation of a photosensitive paste film, (3) irradiation with active energy rays, and (4) removal of uncured portions of the photosensitive paste film are repeated until the desired number of layers is obtained.

[0108] Finally, (1) the fabrication of the insulating sheet is repeated the required number of times until an insulating sheet is formed on the uppermost wiring pattern. This results in a laminated structure comprising multiple layers of insulating sheets and wiring patterns, with the wiring patterns interlayer-connected via via holes 3.

[0109] The resulting laminated structure is divided into chip shapes using a dicing machine. Subsequently, the support film used to prepare the first insulating sheet layer is peeled off.

[0110] (5) Firing Next, the chip-shaped laminated structure is fired. This firing process sinters multiple wiring patterns to form multiple coil wirings 2, and simultaneously forms a coil 5 in which these multiple coil wirings 2 are electrically connected. In addition, multiple insulating sheets are sintered to form a base body 4 containing multiple insulating layers 40. The firing temperature is not particularly limited and can be set appropriately considering the type of material used, etc.

[0111] After firing, a first external electrode 6a and a second external electrode 6b are formed on the outside of the base body 4. This completes the process to obtain the laminated coil component 10 shown in Figure 1.

[0112] Furthermore, a plating layer having a single-layer or multi-layer structure may be provided on the outer surfaces of the first external electrode 6a and the second external electrode 6b by electrolytic plating or electroless plating.

[0113] [Second Embodiment] The second embodiment differs from the first embodiment in the type of radical scavenger contained in the photosensitive paste. This difference in configuration is described below. The other configurations of the second embodiment are the same as those of the first embodiment, so their description is omitted. In the second embodiment, the configuration of the electronic components, the method of forming the wiring pattern, and the method of manufacturing the electronic components are the same as those of the first embodiment, so their description is omitted.

[0114] In this embodiment, the radical scavenger has a benzotriazole structure. The radical scavenger having a benzotriazole structure (hereinafter referred to as a benzotriazole-based radical scavenger) facilitates the uniform application of the photosensitive paste.

[0115] Benzotriazole-based radical scavengers The benzotriazole structure has a five-membered ring containing three nitrogen atoms and a benzene ring. A molecule may contain one or more benzotriazole structures, and may also contain two or more. Multiple benzotriazole structures may be the same or different.

[0116] Benzotriazole-based radical scavengers include, for example, those with the following general formula: [ka] (In the formula, R b X represents one to four groups bonded to a benzene ring, independently representing a hydrogen atom, a hydroxyl group, a hydrocarbon group, a carboxyl group, an amino group, or a halogen atom. X represents a group bonded to a nitrogen atom, representing a hydrogen atom, a hydroxyl group, a hydrocarbon group, a carboxyl group, an amino group, or a halogen atom. It is represented as follows.

[0117] R b R has one or more atoms bonded to the benzene ring, and may have two or more atoms bonded to it. b It has four or fewer R atoms bonded to the benzene ring, and may have three or fewer. b They may be of the same species or different species. b It may be a hydrogen atom.

[0118] X typically has a phenol group. A phenol group is represented by, for example, the following general formula: [ka] (In the formula, R x(These are one to four groups bonded to a benzene ring, each independently representing a hydrogen atom, a hydroxyl group, a hydrocarbon group, a carboxyl group, an amino group, or a halogen atom.) It is represented as follows.

[0119] R x It has one or more bonds to the benzene ring, and may have two or more bonds. x It has four or fewer R atoms bonded to the benzene ring, and may have three or fewer. x They may be of the same species or different species.

[0120] at least one R x This may be an alkyl group, an alkyl group having 1 to 10 carbon atoms, or an alkyl group having 1 to 8 carbon atoms.

[0121] R x This is an alkyl ester group (-C(=O)OR x1 ) may have R x1 This is, for example, a linear or branched alkyl group having 1 to 20 carbon atoms. The alkyl ester group may be directly bonded to the benzene ring, or it may be bonded to the benzene ring via an alkyl group having 1 to 6 carbon atoms, for example.

[0122] The benzene ring of the phenol group may be directly bonded to the nitrogen atom constituting the benzotriazole structure. This can suppress the change in the photocurability of the photosensitive paste over time. A radical scavenger having a benzotriazole structure and a phenol group can be considered a benzotriazole-based radical scavenger.

[0123] A molecule may contain one or more phenol groups, or two or more. Multiple substituents on phenol groups (R x The number and types of ) may be the same, but may also be different.

[0124] Benzotriazole-based radical scavengers having a phenol group include, for example, those with the following general formula: [ka] (In the formula, R b and R x (This is synonymous with the above.) It is represented as follows.

[0125] Examples of benzotriazole-based radical scavengers include 1,2,3-benzotriazole, 4-carboxy-1,2,3-benzotriazole, 5-carboxy-1,2,3-benzotriazole, methylbenzotriazole, carboxybenzotriazole, carboxymethylbenzotriazole, 1-[N,N-bis(2-ethylhexyl)aminomethyl]benzotriazole, 1-[N,N-bis(2-ethylhexyl)aminomethyl]methylbenzotriazole, and 2,2′-[[(methyl-1H-benzotriazole-1-yl)methyl]imino]bisethanol.

[0126] Examples of benzotriazole-based radical scavengers having a phenol structure include 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-5'-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)benzotriazole, 2-(5-tert-butyl-2-hydroxyphenyl)benzotriazole, 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole, and 2-(2-hydroxy-3,5-di-tert -Octylphenyl)benzotriazole, 2-[2'-hydroxy-3',5'-bis(α,α'-dimethylbenzyl)phenyl]benzotriazole), methyl-3-[3-tert-butyl-5-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]propionate condensate with polyethylene glycol, bis{β-[3-(2H-benzotriazol-2-yl)-4-hydroxy-5-tert-butylphenyl]propionate condensate with polyethylene glycol 300, isooctyl-3-[3-(2H-benz Zotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl]propionate, 2-(3-dodecyl-5-methyl-2-hydroxyphenyl)benzotriazole, 2-[2-hydroxy-5-(1,1,3,3-tetramethylbutyl)phenyl]benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole, 2-(2'-hydroxy-4'-octoxyf Phenyl)benzotriazole, 2-[2'-hydroxy-3'-(3",4",5",6"-tetrahydrophthalimidomethyl)-5'-methylphenyl]benzotriazole, 2,2-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazole-2-yl)phenol], 2-(2H-benzotriazole-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 6,Examples include 6'-bis(2H-benzotriazol-2-yl)-4,4'-bis(2-hydroxyethyl)-2,2'-methylenediphenol.

[0127] [Third Embodiment] The third embodiment differs from the first embodiment in the type of radical scavenger contained in the photosensitive paste. This difference in configuration is described below. The other configurations of the third embodiment are the same as those of the first embodiment, so their description is omitted. In the third embodiment, the configuration of the electronic components, the method of forming the wiring pattern, and the method of manufacturing the electronic components are the same as those of the first embodiment, so their description is omitted.

[0128] In this embodiment, the radical scavenger has a hindered amine structure. A radical scavenger having a hindered amine structure (hereinafter referred to as a hindered amine-based radical scavenger) can suppress changes in the viscosity of the photosensitive paste.

[0129] <<Hindered amine-based radical scavengers>> The hindered amine structure has 2,2,6,6-tetramethylpiperidine as its basic skeleton.

[0130] A molecule may contain one or more hindered amine structures, and may also contain two or more. Multiple hindered amine structures may be the same or different.

[0131] Hindered amine radical scavengers include, for example, those with the following general formula: [ka] (In the formula, R c (where Y is a group consisting of one to three groups bonded to a piperidine ring, each independently representing a hydrogen atom, a hydroxyl group, a hydrocarbon group, a carboxyl group, an amino group, or a halogen atom; and Y is a group bonded to a nitrogen atom, each representing a hydrogen atom, a hydroxyl group, a hydrocarbon group, a carboxyl group, an amino group, or a halogen atom.) It is represented as follows.

[0132] Rc R has one or more bonds to the piperidine ring, and may have two or more bonds. c It has three or fewer R atoms bonded to the piperidine ring. c They may be of the same species or different species.

[0133] at least one R c R may be a hydrocarbon group, and may be a hydrocarbon group having a carbonyloxy structure. c This may be an amino group or a tertiary amino group.

[0134] Y is typically a hydrocarbon group. In this embodiment, Y is OR 1 Group (R 1 R represents a hydrocarbon group. 1 R may be an alkyl group having 1 to 20 carbon atoms, or an alkyl group having 5 to 15 carbon atoms. 1 R may be linear. 1 It is acceptable for it to be saturated.

[0135] Y as OR 1 Hindered amine-based radical scavengers containing a group are also called N-OR type hindered amines. Radical scavengers that are N-OR type hindered amines improve the dispersibility of inorganic powders in photosensitive pastes.

[0136] N-OR type hindered amines are, for example, those with the following general formula: [ka] (In the formula, R c This is synonymous with the above, and R 1 (This represents a hydrocarbon group.) It is represented as follows.

[0137] Examples of N-OR type hindered amines include the reaction product of bis(2,2,6,6-tetramethyl-4-piperidyl)=decandioate with 2-hydroperoxy-2-methylpropane and octane, bis[2,2,6,6-tetramethyl-1-(undecyloxy)piperidine-4-yl]=carbonate, and 2,4-bis[N-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidyl-4-yl)amino]-6-(2-hydroxyethylamine)-1,3,5-triazine.

[0138] (Variation 1) In a modified example of this embodiment, Y is COR 2 Group (R 2 R represents a hydrocarbon group. 2 This may be an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 3 carbon atoms, or a methyl group.

[0139] Y as COR 2 Hindered amine-based radical scavengers containing a group are also called N-COR type hindered amines. Radical scavengers that are N-COR type hindered amines improve the wettability of photosensitive pastes to substrates.

[0140] N-COR type hindered amines are, for example, those with the following general formula: [ka] (In the formula, R c This is synonymous with the above, and R 2 (This represents a hydrocarbon group.) It is represented as follows.

[0141] An example of an N-COR type hindered amine is 1-(1-acetyl-2,2,6,6-tetramethyl-4-piperidyl)-3-dodecylpyrrolidine-2,5-dione.

[0142] (Modification 2) In other modifications of this embodiment, Y is R 3Group (R 3 R represents an alkyl group directly bonded to the nitrogen atom. 3 This may be an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 3 carbon atoms, or a methyl group.

[0143] Y as R 3 Hindered amine-based radical scavengers containing a specific group are also called NR-type hindered amines. The use of NR-type hindered amine radical scavengers improves the flexibility in setting development times.

[0144] NR-type hindered amines are, for example, those with the following general formula: [ka] (In the formula, R c This is synonymous with the above, and R 3 (This represents an alkyl group directly bonded to the nitrogen atom.) It is represented as follows.

[0145] R 3 NR-type hindered amines, in which the group is a methyl group, are, for example, those with the following general formula: [ka] (In the formula, R c This is synonymous with the above. It is represented as follows.

[0146] Examples of NR-type hindered amines include bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)2-(3,5-di-tert-butyl-4-hydroxybenzyl)-2-butylmalonate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)-[[3,5-bis(1,1-dimethylethyl-4-hydroxyphenyl]methyl]butylmalonate, and mixtures of bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and methyl-1,2,2,6,6-pentamethyl-4-piperidyl-sebacate. [Examples]

[0147] The present invention will be further illustrated by the following examples, but the present invention is not limited thereto. In the examples, "parts" and "%" are based on mass unless otherwise specified.

[0148] [Example 1] (1) Preparation of photosensitive conductive paste The raw materials shown in Table 1 were blended in the following proportions and thoroughly mixed to obtain a photosensitive resin composition.

[0149] [Table 1]

[0150] A photosensitive conductive paste was obtained by blending 22.7 parts of a photosensitive resin composition, 77.0 parts of inorganic powder (Ag powder with an average particle size of 1.5 μm), and 0.3 parts of radical scavenger A (2,5-di-tert-butylbenzene-1,4-diol) and thoroughly mixing them with a three-roll mixer.

[0151] The structural formula of radical scavenger A (2,5-di-tert-butylbenzene-1,4-diol) used in Example 1 is shown below. [ka]

[0152] (2) Creation of wiring patterns The obtained photosensitive conductive paste was screen printed onto an insulating layer (alumina substrate with a thickness of 1 mm), and dried at 60°C for 30 minutes to form a photosensitive conductive paste film with a thickness of 8 μm.

[0153] A photomask with a linear pattern (with a linear opening width of 15 μm and an opening spacing of 45 μm) was prepared. An active energy ray (ultraviolet light with a peak wavelength between 350 nm and 420 nm) was applied to the resulting photosensitive conductive paste film through the photomask, with an integrated light intensity of 1500 mJ / cm². 2 The irradiation was performed under the following conditions.

[0154] Finally, the uncured portion of the photosensitive conductive paste film was removed using an aqueous triethanolamine solution to obtain the wiring pattern.

[0155] [Example 2] A photosensitive conductive paste was prepared and a wiring pattern was obtained in the same manner as in Example 1, except that radical scavenger B (4-methoxyphenol), represented by the following structural formula, was used instead of radical scavenger A. [ka]

[0156] [Example 3] A photosensitive conductive paste was prepared and a wiring pattern was obtained in the same manner as in Example 1, except that radical scavenger C (1,3,5-tris[(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)methyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione), represented by the following structural formula, was used instead of radical scavenger A. [ka]

[0157] [Example 4] A photosensitive conductive paste was prepared and a wiring pattern was obtained in the same manner as in Example 1, except that radical scavenger D (1,2,3-benzotriazole), represented by the following structural formula, was used instead of radical scavenger A. [ka]

[0158] [Example 5] A photosensitive conductive paste was prepared and a wiring pattern was obtained in the same manner as in Example 1, except that radical scavenger E (2-(2'-hydroxy-5'-methylphenyl)benzotriazole), represented by the following structural formula, was used instead of radical scavenger A. [ka]

[0159] [Example 6] A photosensitive conductive paste was prepared and a wiring pattern was obtained in the same manner as in Example 1, except that radical scavenger F (2-[2-hydroxy-5-(1,1,3,3-tetramethylbutyl)phenyl]benzotriazole), represented by the following structural formula, was used instead of radical scavenger A. [ka]

[0160] [Example 7] A photosensitive conductive paste was prepared in the same manner as in Example 1, except that radical scavenger G (bis[2,2,6,6-tetramethyl-1-(undecyloxy)piperidine-4-yl]=carbonate), represented by the following structural formula, was used instead of radical scavenger A, and a wiring pattern was obtained. [ka]

[0161] [Example 8] A photosensitive conductive paste was prepared in the same manner as in Example 1, except that radical scavenger H (a reaction product of bis(2,2,6,6-tetramethyl-4-piperidyl)=decandioate, 2-hydroperoxy-2-methylpropane, and octane), represented by the following structural formula, was used instead of radical scavenger A, and a wiring pattern was obtained. [ka]

[0162] [Example 9] A photosensitive conductive paste was prepared and a wiring pattern was obtained in the same manner as in Example 1, except that radical scavenger I (1-(1-acetyl-2,2,6,6-tetramethyl-4-piperidyl)-3-dodecylpyrrolidine-2,5-dione), represented by the following structural formula, was used instead of radical scavenger A. [ka]

[0163] [Example 10] A photosensitive conductive paste was prepared and a wiring pattern was obtained in the same manner as in Example 1, except that radical scavenger J (bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate), represented by the following structural formula, was used instead of radical scavenger A. [ka]

[0164] [Comparative Example 1] A photosensitive conductive paste was prepared and a wiring pattern was obtained in the same manner as in Example 1, except that radical scavenger A was not included.

[0165] [Resolution evaluation] The obtained wiring patterns were observed using a confocal microscope (Lasertec, Optelics), and the width of five arbitrary straight sections was measured. The average value X (μm) was then calculated. The evaluation results are shown in Table 2. The smaller the difference between the average line width X and the width of the straight aperture (15 μm), the better the resolution.

[0166] [Table 2]

[0167] In the examples, the difference (X-15) between the width of the wiring pattern made with the photosensitive conductive paste and the width of the mask opening was smaller than the width of the opening (15 μm), indicating excellent resolution. On the other hand, in the comparative example, the difference (X-15) between the width of the wiring pattern made with the photosensitive conductive paste and the width of the mask opening was greater than or equal to the width of the opening (15 μm), indicating poor resolution.

[0168] This disclosure is not limited to the embodiments described above, and design modifications are possible without departing from the spirit of this disclosure. For example, the radical scavengers used in each of the first to third embodiments may be combined in various ways.

[0169] In the first to third embodiments, the photosensitive paste is conductive, but the photosensitive paste according to this disclosure may be non-conductive. A non-conductive photosensitive paste can be used, for example, to form insulating films of electronic components.

[0170] In the first to third embodiments, the electronic component has multiple coil wirings, but there may be only one coil wiring.

[0171] In the first to third embodiments, coil components were fabricated using the conductive photosensitive paste according to the present disclosure, but the applications of the conductive photosensitive paste are not limited thereto. The conductive photosensitive paste relating to this disclosure is used in the manufacture of circuit boards such as multilayer ceramic substrates, and electronic components such as active components and passive components other than coil components. Active components are components that amplify, rectify, or convert supplied power. Examples of active components include transistors and various sensors. Passive components are components that consume, store, or release supplied power and do not perform active operations such as amplification and rectification. Examples of passive components include coil components, as well as resistors, capacitors, and thermistors.

[0172] This disclosure includes the following aspects: <1> Photopolymerization initiator and Photopolymerizable monomers, Alkali-soluble polymers and Inorganic powder and A photosensitive paste containing a radical scavenger. <2> The inorganic powder is conductive, <1> The photosensitive paste described in [the document]. <3> The radical scavenger has a phenol structure, <1> or <2> The photosensitive paste described in [the document]. <4> The radical scavenger having the phenol structure further has at least one tert-butyl group or alkoxy group bonded to the benzene ring constituting the phenol structure. <3> The photosensitive paste described in [the document]. <5> The radical scavenger has a benzotriazole structure. <1> or <2> The photosensitive paste described in [the document]. <6> The radical scavenger having the benzotriazole structure further has a phenol group bonded to the nitrogen atom constituting the benzotriazole structure, <5> The photosensitive paste described in [the document]. <7> The radical scavenger has a hindered amine structure. <1> or <2> The photosensitive paste described in [the document]. <8> The radical scavenger having the aforementioned hindered amine structure is a nitrogen atom bonded to the hindered amine structure. 1 Group (R 1 represents a hydrocarbon group. ) <7> The photosensitive paste described in [the document]. <9> The radical scavenger having the aforementioned hindered amine structure is a nitrogen atom bonded to the hindered amine structure COR 2 Group (R 2 represents a hydrocarbon group. ) <7> The photosensitive paste described in [the document]. <10> The radical scavenger having the hindered amine structure is composed of nitrogen atom bonds R constituting the hindered amine structure. 3 Group (R 3) represents an alkyl group directly bonded to the nitrogen atom. <7> The photosensitive paste described in [the document]. <11> Used in forming wiring patterns, <2> And, <2> Subordinate to <3> from <10> A photosensitive paste as described in one of the following. <12> <2> And, <2> Subordinate to <3> from <10> A step of applying a photosensitive paste described in any one of the above onto an insulating sheet to form a photosensitive paste film, A step of irradiating a portion of the photosensitive paste film with active energy rays, A method for forming a wiring pattern, comprising the step of removing the uncured portion of the photosensitive paste film to form a wiring pattern. <13> <2> And, <2> Subordinate to <3> from <10> A step of applying a photosensitive paste described in any one of the above onto an insulating sheet to form a photosensitive paste film, A step of irradiating a portion of the photosensitive paste film with active energy rays, The process involves removing the uncured portion of the photosensitive paste film to form a wiring pattern, A step of laminating insulating sheets on the aforementioned wiring pattern A method for manufacturing an electronic component, comprising the steps of firing the wiring pattern and the insulating sheet to obtain a plurality of insulating layers as a sintered body of the plurality of insulating sheets, and internal wiring as a sintered body of the wiring pattern. <14> A substrate containing multiple insulating layers, Provided inside the aforementioned body, hardened <2> And, <2> Subordinate to <3> from <10> An electronic component comprising an internal wiring as a sintered body of a photosensitive paste described in any one of the above. [Explanation of symbols]

[0173] 2. Coil Wiring 3 Beer Hall 4. Base body 5 coils 5a 1st end 5b 2nd end 6a 1st external electrode 6b 2nd external electrode 10. Laminated coil components 40 Insulating layer 41 1st end face 42 Second end face 43 First aspect 44 Second aspect 45 Bottom 46 Top surface

Claims

[Claim 1] Photopolymerization initiator and Photopolymerizable monomers, Alkali-soluble polymers and Inorganic powder and A photosensitive paste containing a radical scavenger.

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