TWI890835B - Photosensitive conductive paste, cured product, method for producing insulating ceramic layer with circuit pattern, method for producing electronic component, method for producing substrate with circuit pattern, and method for producing inductor - Google Patents

Abstract

The object of the present invention is to provide a photosensitive conductive paste that can form a high-precision circuit pattern and has a small amount of shrinkage during sintering of the circuit pattern.

The present invention provides a photosensitive conductive paste comprising a conductive powder (A) and a photosensitive organic component (B). The conductive powder (A) has a particle size distribution with a median diameter (r) of 3.0 μm to 6.0 μm, and a content ( _V1) of the conductive powder (A) in the total solids composition of the paste is 37% by volume to 55% by volume.

Description

Photosensitive conductive paste, cured product, method for manufacturing insulating ceramic layer with circuit pattern, method for manufacturing electronic component, method for manufacturing substrate with circuit pattern, and method for manufacturing inductor

The present invention relates to a method for manufacturing a photosensitive conductive paste, a cured product, a sintered body, an electronic component, an insulating ceramic layer with a circuit pattern, and a method for manufacturing an electronic component.

In recent years, with the advancement of electronic components toward higher speed, higher frequency, and smaller size, there is a growing demand for substrates used to mount these components to form fine, low-resistance circuit patterns. For example, a photosensitive conductive paste has been proposed that can form high-precision circuit patterns on green sheets while suppressing sintering defects (e.g., see Patent Document 1).

[Prior Art Literature] [Patent Literature]

[Patent Document 1] International Publication No. 2019/202889

As an example of a method for manufacturing electronic components, the following method can be cited: a circuit pattern is formed on an insulating ceramic layer using a photosensitive conductive paste, and the resulting insulating ceramic layer with the circuit pattern is stacked and sintered. However, when using the photosensitive conductive paste described in Patent Document 1, the area where the multiple circuit patterns are stacked shrinks significantly during sintering, and the difference in shrinkage between the stacked layers and the insulating ceramic layer is significant. This can lead to problems such as warping at the ends of the electronic component, defects, and interlayer separation.

Therefore, the object of the present invention is to provide a photosensitive conductive paste that can form a high-precision circuit pattern and has a small amount of shrinkage during sintering of the circuit pattern.

That is, the present invention is a photosensitive conductive paste comprising conductive particles (A) and a photosensitive organic component (B), wherein the median diameter r of the particle size distribution of the conductive particles (A) is from 3.0 μm to 6.0 μm, and the content _V1 of the conductive particles (A) in the total solids is from 37 volume % to 55 volume %.

Furthermore, the present invention is a cured product, which is formed by curing the photosensitive conductive paste of the present invention.

Furthermore, the present invention is a sintered body, which is formed by sintering the photosensitive conductive paste of the present invention.

Furthermore, the present invention is an electronic component comprising the sintered body of the present invention and an insulating ceramic layer.

The present invention also provides a method for manufacturing an insulating ceramic layer with a circuit pattern, comprising: applying the photosensitive conductive paste of the present invention onto the insulating ceramic layer to obtain a coating film; drying the coating film to obtain a dried film; and exposing and developing the dried film to obtain a circuit pattern.

Furthermore, the present invention is a method for manufacturing an electronic component, comprising: a step of obtaining a laminate by sequentially repeating the following steps A to F multiple times on an insulating ceramic layer with a circuit pattern obtained by the method for manufacturing an insulating ceramic layer with a circuit pattern of the present invention, and a step of sintering the laminate; Step A: a step of applying a photosensitive insulating ceramic composition to obtain a coating film, Step B: A: Drying the coating film to obtain a dry film. C: Exposing and developing the dry film to obtain an insulating ceramic layer. D: Applying the photosensitive conductive paste of the present invention on the insulating ceramic layer to obtain a coating film. E: Drying the coating film to obtain a dry film. F: Exposing and developing the dry film to obtain a circuit pattern.

The present invention is also directed to a method for manufacturing a circuit patterned substrate, characterized by comprising the steps of: coating a photosensitive insulating ceramic composition on a substrate; exposing the photosensitive insulating ceramic composition coating to a desired pattern; developing the exposed photosensitive insulating ceramic composition coating to form an insulating layer having trenches; coating the photosensitive conductive paste of the present invention on the insulating layer and within the trenches; exposing the photosensitive conductive paste coating to the trenches; and The exposed photosensitive conductive paste film is developed to form a circuit pattern at locations corresponding to the trenches. The trenches have a pyramidal shape on their sides.

Furthermore, the present invention is a method for manufacturing an inductor, characterized in that the method comprises the steps of manufacturing a substrate with a circuit pattern according to the present invention.

By using the photosensitive conductive paste of the present invention, it is possible to produce high-precision circuit patterns with little shrinkage during sintering.

[Form used to implement the invention]

<Photosensitive Conductive Paste> The photosensitive conductive paste of the present invention contains conductive particles (A) and a photosensitive organic component (B).

<Conductive Particles (A)> The photosensitive conductive paste of the present invention contains conductive particles (A). Examples of conductive particles (A) include metals such as silver, gold, copper, platinum, palladium, tin, nickel, aluminum, tungsten, molybdenum, ruthenium oxide, chromium, titanium, and indium, as well as powders of their alloys and carbon powder. Two or more of these metals may also be included. From the perspective of conductivity, silver, copper, and gold are preferred, and from the perspectives of cost and stability, silver is particularly preferred.

It is important that the median diameter r of the particle size distribution of the conductive particles (A) is greater than 3.0 μm and less than 6.0 μm. By having r greater than 3.0 μm, preferably greater than 3.5 μm, and more preferably greater than 4.0 μm, the movement of the conductive particles (A) during the sintering step can be suppressed, minimizing the amount of shrinkage during sintering. Furthermore, it is possible to prevent the light transmittance of the coating from being reduced during the exposure step, resulting in peeling during development and making it difficult to form fine patterns. On the other hand, by having r less than 6.0 μm, preferably less than 5.5 μm, and more preferably less than 5.0 μm, it is possible to prevent the probability of contact between the conductive powders during sintering, which can reduce the volume resistivity of the conductive pattern. Furthermore, the straightness of the wiring ends in fine wiring is improved, which can prevent short circuits between wirings.

In the present invention, the median diameter can be measured by a laser light scattering method using a particle size distribution measuring apparatus ("Microtrac" HRA Model No. 9320-X100 manufactured by Nikkiso Co., Ltd.).

It is important that the content _V1 of the conductive particles (A) in the total solids content is 37 volume % or more and 55 volume % or less. By keeping _V1 at 37 volume % or more, preferably 40 volume % or more, and more preferably 42 volume % or more, the amount of solids lost during sintering can be minimized, thereby minimizing shrinkage. On the other hand, by keeping _V1 at 55 volume % or less, preferably 52 volume % or less, and more preferably 50 volume % or less, the coating's light transmittance can be prevented from being reduced during the exposure step, making it difficult to form fine patterns.

The volume of the conductive particles (A), the volume of the inorganic particles other than the conductive particles (C) described below, and the solid volume of the photosensitive organic component (B) in the present invention are determined as follows. First, the paste is filtered to separate into a mixture of conductive and inorganic particles and the solid content of the photosensitive organic component (B). The conductive powder and inorganic particles are then fractionated and their respective masses are measured. The organic component is dried at 100°C for 2 hours, and the post-drying mass is measured. The volume can be calculated from the mass and density of each component.

<Photosensitive Organic Component (B)> The photosensitive conductive paste of the present invention contains a photosensitive organic component (B). In the present invention, a photosensitive organic component refers to a group of organic components that at least partially contains a component that changes its properties or causes a change in response to light. In other words, not all components of the photosensitive organic component in the present invention need contribute to photosensitivity.

The photosensitive organic component (B) preferably comprises an alkali-soluble resin, a photopolymerization initiator, and a solvent. Here, an alkali-soluble resin refers to a resin having an alkali-soluble group. Examples of alkali-soluble groups include carboxyl groups, phenolic hydroxyl groups, sulfonic acid groups, and thiol groups. Carboxyl groups are particularly preferred due to their high solubility in alkaline developers.

As the alkali-soluble resin, acrylic resin is preferred, and copolymers of acrylic monomers having carbon-carbon double bonds and other monomers are preferred.

Examples of acrylic monomers having carbon-carbon double bonds include: Acrylic esters having a carbon-carbon double bond and a carbon chain aliphatic hydrocarbon group with 1 to 18 carbon atoms, such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tertiary butyl acrylate, n-pentyl acrylate, isodecyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, allyl acrylate, lauryl acrylate, and stearyl acrylate; Acrylic esters having a carbon-carbon double bond and a carbon chain aromatic hydrocarbon group with 6 to 10 carbon atoms, such as benzyl acrylate, phenyl acrylate, 1-naphthyl acrylate, and 2-naphthyl acrylate; Acrylates having a cyclic aliphatic hydrocarbon group with 6 to 15 carbon atoms, such as cyclohexyl acrylate, dicyclopentyl acrylate, 4-tert-butylcyclohexyl acrylate, dicyclopentenyl acrylate, dicyclopentadienyl acrylate, isobornyl acrylate, and 3,3,5-trimethylcyclohexyl acrylate; These acrylates may be replaced with methacrylates. Two or more of these may also be used.

Examples of copolymerization components other than acrylic monomers include: Styrenes such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, chloromethylstyrene, and hydroxymethylstyrene; Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, and vinyl acetate, and their anhydrides. Two or more of these may also be used.

Acrylic resins preferably have carbon-carbon double bonds in the side chains or at the molecular ends, which can increase the curing reaction speed during exposure. Examples of structures with carbon-carbon double bonds include vinyl, allyl, acrylic, and methacrylic groups. Two or more of these groups may also be present.

Examples of methods for introducing carbon-carbon double bonds into acrylic resins include reacting compounds containing epoxypropyl or isocyanate groups and carbon-carbon double bonds, acryloyl chloride, methacryloyl chloride, allyl chloride, etc., with alkyl, amino, hydroxyl, or carboxyl groups in acrylic resins.

Examples of compounds having a glycidyl group and a carbon-carbon double bond include glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether, glycidyl ethyl acrylate, crotonyl glycidyl ether, glycidyl crotonate, glycidyl isocrotonate, and "CYCLOMER" (registered trademark) M100 and A200 manufactured by Daicel Chemical Industries, Ltd. Two or more of these may be used.

Examples of compounds having an isocyanate group and a carbon-carbon double bond include acryloyl isocyanate, methacryloyl isocyanate, ethyl acryloyl isocyanate, and methacryloyl ethyl isocyanate. Two or more of these may be used.

Photopolymerization initiators are compounds that absorb short-wavelength light such as ultraviolet light and decompose, or generate free radicals through hydrogen abstraction reactions.

Examples of photopolymerization initiators that decompose upon absorption of ultraviolet light include 1,2-octanedione, diphenyl ketone, methyl o-benzoylbenzoate, 4,4'-bis(dimethylamino)diphenyl ketone, 4,4'-bis(diethylamino)diphenyl ketone, 4-benzoyl-4'-methyldiphenyl ketone, dibenzyl ketone, 2,2'-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methylpropiophenone, Michler's ketone, 2-methyl-[4-(methylthio)phenyl]-2-(4- Alkyl phenone-based photopolymerization initiators such as 2-methyl[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 4-azidobenzylideneacetophenone, 2,6-bis(p-azidobenzylidene)cyclohexanone, and 6-bis(p-azidobenzylidene)-4-methylcyclohexanone; acylphosphine oxide-based photopolymerization initiators such as 2,4,6-trimethylbenzyl-diphenyl-phosphine oxide and bis(2,4,6-trimethylbenzyl)-phenylphosphine oxide; 1-[4-(phenylthio)-2-(O-benzoyloxime)], ethyl ketone, 1-[9-ethyl-6-(2-methylbenzyl)- Oxime esters of 1-phenyl-1,2-butanedione-2-(O-methoxycarbonyl)oxime, 1-phenyl-propanedione-2-(O-ethoxycarbonyl)oxime, 1-phenyl-propanedione-2-(O-benzoyl)oxime, 1,3-diphenyl-propanedione-2-(O-ethoxycarbonyl)oxime, and 1-phenyl-3-ethoxy-propanedione-2-(O-benzoyl)oxime are photopolymerization initiators.

Examples of photopolymerization initiators that generate free radicals through hydrogen abstraction reactions include phenyl ketone, anthraquinone, thioxanthine, and methyl phenylglyoxylate. Two or more of these may also be included.

The solvent is used to moisten or dissolve the components of the photosensitive conductive paste, providing excellent coating properties.

Examples of the solvent include N,N-dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone, dimethylimidazolidinone, dimethyl sulfoxide, diethylene glycol monoethyl ether, dipropylene glycol methyl ether, dipropylene glycol n-propyl ether, dipropylene glycol n-butyl ether, tripropylene glycol methyl ether, tripropylene glycol n-butyl ether, diethylene glycol monoethyl ether acetate, dipropylene glycol methyl ether acetate, propylene glycol phenyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, γ-butyrolactone, ethyl lactate, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, ethylene glycol mono-n-propyl ether, diacetone alcohol, tetrahydrofurfuryl alcohol, and propylene glycol monomethyl ether acetate. Two or more of these may be contained.

The photosensitive organic component (B) may also contain a photosensitive monomer, a dispersant, a plasticizer, a leveling agent, a surfactant, a silane coupling agent, a defoaming agent, a stabilizer, etc., within a range that does not impair the desired properties.

<Inorganic Particles (C) Other Than Conductive Particles (A)> The photosensitive conductive paste of the present invention preferably further contains inorganic particles (C) other than the conductive particles (A). The inclusion of these inorganic particles (C) prevents sintering of the conductive particles (A), effectively suppressing shrinkage of the photosensitive conductive paste during sintering.

The inorganic particles (C) preferably contain at least one selected from the group consisting of titanium oxide, aluminum oxide, silicon oxide, cordierite, andalusite, spinel, barium titanate, and zirconium oxide. Among these, aluminum oxide, titanium oxide, and silicon oxide are particularly preferred, and silicon oxide is particularly preferred from the perspective of micromachinability.

The median diameter of the particle size distribution of the inorganic particles (C) is preferably 1 to 100 nm. A median diameter of 1 nm or greater in the particle size distribution of the inorganic particles (C) prevents sintering of the conductive powder and further suppresses shrinkage. Furthermore, a median diameter of 100 nm or less reduces the resistance of the resulting circuit pattern after sintering.

The volume ratio _V2 of the inorganic particles (C) relative to 100 volume % of the conductive particles (A) is preferably 3 volume % or more and 10 volume % or less. By setting _V2 to 3 volume % or more, more preferably 3.5 volume % or more, and even more preferably 4 volume % or more, migration of the conductive powder during sintering can be inhibited, further suppressing shrinkage during sintering. Furthermore, by setting _V2 to 10 volume % or less, more preferably 7 volume % or less, and even more preferably 5.5 volume % or less, the resistance of the resulting circuit pattern can be reduced after sintering.

The photosensitive conductive paste of the present invention preferably has a product of r, _V1 , and _V2 (r× _V1 × _V2) of 500 to 3300. By setting r× _V1 × _V2 to 500 or more, more preferably 600 or more, and even more preferably 700 or more, shrinkage during sintering can be further suppressed. On the other hand, by setting r× _V1 × _V2 to 3300 or less, more preferably 2500 or less, and even more preferably 1500 or less, insufficient shrinkage, which could lead to a mismatch in shrinkage with the dielectric layer, can be prevented, thereby preventing the formation of voids between the dielectric and the electrode.

<Production of Photosensitive Conductive Paste> The photosensitive conductive paste of the present invention can be obtained by dissolving and/or dispersing conductive particles (A) and a photosensitive organic component (B) other than the solvent in a solvent. Preferably, inorganic particles (C) are further dissolved and/or dispersed in the solvent. Examples of dissolving and/or dispersing apparatus include a three-roller disperser, a ball mill, and a kneading machine.

<Cured Product> Next, the cured product will be described. The cured product of the present invention is formed by curing the photosensitive conductive paste of the present invention.

The shape of the cured product of the present invention is not particularly limited.

From the perspective of electrical conductivity, the film thickness t of the cured product of the present invention is preferably 5 μm or greater, more preferably 10 μm or greater. On the other hand, from the perspective of forming fine patterns onto small areas, the film thickness t is preferably 35 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less.

The cured product may also have a predetermined pattern shape. Examples of such pattern shapes include stripes and spirals.

The best ratio of film thickness t to line width w for the cured material is t/w, which is greater than 0.5 and less than 1.0. With a t/w ratio of 0.5 to 1.0, a high aspect ratio wiring can be achieved, achieving both fine wiring and low resistance.

Furthermore, the cured material preferably has a ratio (b/a) of the bottom width (b) to the top width (a) of 0.6 or more and 1.0 or less. By having b/a of 0.6 or more and 1.0 or less, a wiring with a large cross-section and low resistance can be obtained.

The cured material can also be stacked to create a laminate. The preferred number of layers is 1 to 30. By setting the number of layers to 1 or more, the thickness of the specified pattern can be increased. On the other hand, by setting the number of layers to 30 or less, the impact of inter-layer alignment deviation can be reduced.

<Production of Cured Articles> A cured article can be obtained, for example, by applying the photosensitive conductive paste of the present invention to a substrate, drying it, and then photocuring it by exposure. When producing a cured article with a pattern, the pattern can be formed by exposure and then developing the image.

Examples of coating methods used in the coating step include rotary coating using a rotary machine, spray coating, roll coating, screen printing, offset printing, gravure printing, letterpress printing, flexographic printing, and methods using knife coaters, die coaters, curtain coaters, meniscus coaters, or rod coaters. Screen printing is particularly preferred because the resulting coated film has excellent surface flatness and film thickness can be easily adjusted by selecting a screen.

Drying methods include heat drying using a heating device such as an oven, hot plate, or infrared ray, as well as vacuum drying. Heating temperatures of 40°C to 130°C are preferred. A drying temperature above 40°C allows for efficient solvent removal by volatilization. Meanwhile, a drying temperature below 130°C inhibits thermal crosslinking of the photosensitive conductive paste, reducing residue in non-exposed areas during the subsequent exposure and development steps, facilitating the formation of finer patterns. Heating time is preferably between 5 minutes and 1 hour.

Exposure methods include those using a mask and those without a mask. Maskless exposure methods include full-surface exposure and direct imaging using laser light. Examples of exposure equipment include steppers and proximity scanners. Active light sources for exposure include near-ultraviolet light, ultraviolet light, electron beams, X-rays, and laser light, with ultraviolet light being preferred. Ultraviolet light sources include low-pressure mercury lamps, high-pressure mercury lamps, ultrahigh-pressure mercury lamps, halogen lamps, and germicidal lamps, with ultrahigh-pressure mercury lamps being preferred.

Examples of the developer in the case of alkaline development include aqueous solutions of tetramethylammonium hydroxide, diethanolamine, diethylaminoethanol, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, triethylamine, diethylamine, methylamine, dimethylamine, dimethylaminoethyl acetate, dimethylaminoethanol, dimethylaminoethyl methacrylate, cyclohexylamine, ethylenediamine, and hexamethylenediamine.

To these aqueous solutions may also be added polar solvents such as N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and γ-butyrolactone; alcohols such as methanol, ethanol, and isopropyl alcohol; esters such as ethyl lactate and propylene glycol monomethyl ether acetate; ketones such as cyclopentanone, cyclohexanone, isobutyl ketone, and methyl isobutyl ketone; and surfactants.

Examples of developing methods include a method of spraying a developer onto the exposed dry film while the substrate with the dried film formed thereon is allowed to stand still or rotate, a method of immersing the substrate with the dried film formed thereon in the developer, and a method of applying ultrasonic waves while immersing the substrate with the dried film formed thereon in the developer.

The hardened product obtained by development can also be cleaned with a cleaning solution. Examples of the cleaning solution include water; aqueous solutions of alcohols such as ethanol and isopropyl alcohol; and aqueous solutions of esters such as ethyl lactate and propylene glycol monomethyl ether acetate.

<Sintered Body> The sintered body of the present invention is formed by sintering the aforementioned photosensitive conductive paste of the present invention.

Examples of sintering methods include heat treatment at 300-600°C for 5 minutes to several hours, followed by further heat treatment at 850-900°C for 5 minutes to several hours.

<Electronic Components> The electronic component of the present invention comprises a sintered body and an insulating ceramic layer. The insulating ceramic layer can suppress unintentional short circuits between sintered bodies.

The insulating ceramic layer preferably has a composition of SiO ₂ 25-50 (mass%), Al ₂ O ₃ 30-60 (mass%), B ₂ O ₃ 5-20 (mass%), and K ₂ O 0.3-3 (mass%), calculated as oxides. This composition facilitates achieving the relative dielectric constant ε described below.

The relative dielectric constant ε of the insulating ceramic layer is preferably between 3.0 and 6.0. Setting ε to 6.0 or less allows for a high-performance inductor with minimal loss when using the insulating ceramic layer with a circuit pattern in a multilayer chip inductor. Furthermore, setting ε to 3.0 or greater improves mechanical strength.

The electronic component of the present invention may also have terminal electrodes outside the sintered body and the insulating ceramic layer. Examples of materials for forming the terminal electrodes include nickel and tin.

<Method for Manufacturing an Insulating Ceramic Layer with a Circuit Pattern> One method for manufacturing an insulating ceramic layer with a circuit pattern of the present invention comprises: a coating step of applying the photosensitive conductive paste of the present invention onto an insulating ceramic layer to form a coating film; a step of drying the coating film to form a dried film; and a step of exposing and developing the dried film to form a circuit pattern.

First, the photosensitive conductive paste of the present invention is coated on an insulating ceramic layer to obtain a coating film.

The insulating ceramic layer is obtained by coating an insulating ceramic composition or a photosensitive insulating ceramic composition entirely or partially on a transparent film containing a resin such as alumina, quartz glass, sodium calcium glass, chemically strengthened glass, "Pyrex" (registered trademark) glass, synthetic quartz plate, epoxy resin substrate, polyetherimide resin substrate, polyetherketone resin substrate, polysulfone resin substrate, polyethylene terephthalate film (hereinafter referred to as "PET film"), cycloolefin polymer film, polyimide film, polyester film, polyarylamide film, or optical resin plate, and then drying the coating.

As coating methods, screen printing, rod coating, roll coating, die coating, knife coating, etc. can be used.

When using a photosensitive insulating ceramic composition, patterning can also be performed by photolithography.

The insulating ceramic composition preferably contains insulating ceramic powder, a binder resin, and a solvent. Examples of insulating ceramic powders include Pal Serum (registered trademark), BT149 (manufactured by Nippon Chemical Industry Co., Ltd.), L5 (manufactured by Ferro Corp.), and SG-200 (manufactured by Nippon Talc Co., Ltd.). Two or more of these may be included. Examples of binder resins include acrylic resins, polyvinyl butyral resins, polyvinyl alcohol resins, cellulose resins, and methyl cellulose resins. Two or more of these may also be included.

As the solvent for the insulating ceramic composition, the solvent contained in the photosensitive organic component (B) of the aforementioned photosensitive conductive paste can be preferably used.

The photosensitive insulating ceramic composition preferably includes, in addition to the aforementioned insulating ceramic powder and solvent, an alkali-soluble resin and a photopolymerization initiator.

As the alkali-soluble resin and photopolymerization initiator used in the photosensitive insulating ceramic composition, the alkali-soluble resin and photopolymerization initiator contained in the photosensitive organic component (B) of the aforementioned photosensitive conductive paste can be preferably used.

As a coating step for obtaining a coating film by coating a photosensitive conductive paste on an insulating ceramic layer, the coating method in the aforementioned method for producing a cured product can be exemplified.

Next, the coated film is dried to obtain a dry film.

As the drying method in the drying step, the following can be cited as an example: the drying method in the aforementioned method for producing the cured product.

Next, the dried film is exposed and developed to obtain a circuit pattern.

As the exposure method in the exposure and development step, the method exemplified as the exposure method in the aforementioned method for producing a cured product can be cited.

The exposed dried film is developed and dissolved using a developer to remove the unexposed areas, thereby forming a desired pattern. Examples of the developer include the developer used in the aforementioned method for producing a cured product.

Examples of developing methods include a method of spraying a developer onto the exposed dried film while the insulating ceramic layer is stationary or rotating, a method of immersing the insulating ceramic layer having the exposed dried film in the developer, and a method of applying ultrasonic waves while immersing the insulating ceramic layer having the exposed dried film in the developer.

The pattern obtained by development may be cleaned with a cleaning liquid. Examples of the cleaning liquid include the cleaning liquid used in the aforementioned method for producing a cured product.

The obtained insulating ceramic with circuit patterns can also be stacked to form a laminate.

The resulting insulating ceramic layer with the circuit pattern is preferably sintered to form a sintered body. Examples of sintering methods include those described as examples of sintering methods for manufacturing sintered bodies. The circuit pattern formed on the insulating ceramic layer comprises a composite of conductive powder (A) and a photosensitive organic component (B). During sintering, the conductive powder (A) comes into contact with each other, thereby exhibiting conductivity.

<Method for Manufacturing Electronic Components> One method for manufacturing an electronic component of the present invention comprises: a step of obtaining a plurality of insulating ceramic layers with a circuit pattern using the method for manufacturing an insulating ceramic layer with a circuit pattern of the present invention; a step of laminating and hot-pressing the plurality of insulating ceramic layers with a circuit pattern to obtain a laminate; and a step of sintering the laminate.

First, a plurality of insulating ceramic layers with circuit patterns are obtained by the method for manufacturing the insulating ceramic layer with circuit patterns of the present invention.

Next, the plurality of insulating ceramic layers with circuit patterns are stacked and heat-pressed to form a laminate. Examples of stacking methods include stacking the insulating ceramic layers with circuit patterns using vias. Examples of heat-pressing equipment include hydraulic presses. The heat-pressing temperature is preferably between 90 and 130°C, and the heat-pressing pressure is preferably between 5 and 20 MPa.

Next, the laminate is sintered. Examples of sintering methods include the sintering method described above as an example of the sintering method used in the sintered body manufacturing method.

One method of manufacturing an electronic component of the present invention comprises: a step of sequentially repeating the following steps A to F multiple times on an insulating ceramic layer with a circuit pattern obtained by the method of manufacturing an insulating ceramic layer with a circuit pattern of the present invention to obtain a laminate; and a step of sintering the laminate. Step A: Applying a photosensitive insulating ceramic composition to obtain a coating film Step B: Drying the coating film to obtain a dried film Step C: Exposing and developing the dried film to obtain an insulating ceramic layer Step D: Applying the photosensitive conductive paste of the present invention on the insulating ceramic layer to obtain a coating film Step E: Drying the coating film to obtain a dried film Step F: Exposing and developing the dried film to obtain a circuit pattern

First, in step A, a photosensitive insulating ceramic composition is applied to the insulating ceramic layer with a circuit pattern obtained by the method for producing an insulating ceramic layer with a circuit pattern of the present invention to form a coating film. The photosensitive insulating ceramic composition used in the aforementioned method for producing an insulating ceramic layer with a circuit pattern can be used. The coating method described above as an example of the coating method in the method for producing a cured product can be exemplified.

Next, in step B, the resulting coated film of the photosensitive insulating ceramic composition is dried to obtain a dried film. Examples of the drying method include the drying method described above as an example of the method for producing the cured product.

Next, in step C, the resulting dried film is exposed and developed to obtain an insulating ceramic layer. Examples of the exposure method include the exposure method described above as an example in the method for producing a cured product. Examples of the development method include the development method described above as an example in the method for producing a cured product.

Next, in step D, the photosensitive conductive paste of the present invention is applied onto the obtained insulating ceramic layer to obtain a coating film.

Next, in step E, the obtained coated film of the photosensitive conductive paste is dried to obtain a dried film.

Next, in step F, the resulting dried film is exposed and developed to obtain a circuit pattern.

Next, the above steps A to F are repeated multiple times to obtain a layered volume.

Next, the obtained laminate is sintered. Examples of sintering methods include the sintering method described above as an example of the sintering method for producing a sintered body.

<Method for Manufacturing a Substrate with a Circuit Pattern> The method for manufacturing a substrate with a circuit pattern of the present invention preferably comprises: coating a photosensitive insulating ceramic composition on a substrate; exposing the coating of the photosensitive insulating ceramic composition to a desired pattern; and developing the exposed coating of the photosensitive insulating ceramic composition to form an insulating layer having grooves. , applying the photosensitive conductive paste of the present invention on the insulating layer and in the trench, exposing the photosensitive conductive paste film corresponding to the trench, and developing the exposed photosensitive conductive paste film to form a circuit pattern at a position corresponding to the trench; the trench has a pyramidal shape on its side.

Because the trench has a pyramidal shape on the side, even a paste containing conductive powder with large particle size can easily release bubbles when the photosensitive conductive paste is applied to the trench and filled, achieving conductivity close to the design expectation.

The ratio (d/c) of the top width (c) to the bottom width (d) of the pyramidal trench is preferably 0.30 or greater and less than 1.00. Setting it to less than 1.00, more preferably 0.95 or less, and even more preferably 0.90 or less, improves the fillability of the photosensitive conductive paste. Furthermore, setting it to 0.3 or greater, more preferably 0.5 or greater, and even more preferably 0.7 or greater, increases the cross-sectional area of the circuit pattern.

The viscosity of the photosensitive conductive paste is preferably 3 to 50 Pa·s. By setting it to 50 Pa·s or less, more preferably 40 Pa·s or less, and even more preferably 30 Pa·s or less, it can be easily filled into pyramidal trenches. Furthermore, by setting it to 3 Pa·s or more, more preferably 5 Pa·s or more, and even more preferably 10 Pa·s or more, it can be easily applied.

The viscosity of the photosensitive conductive paste was measured using a Brookfield viscometer at 10 rpm.

The TI value (thixotropic index) of photosensitive conductive paste is preferably below 2.0, below 1.5 is more preferred, and below 1.3 is even more preferred. This allows for excellent leveling and filling into trenches.

The TI value of a photosensitive conductive paste is defined as the ratio (e/f) of the value (e) measured at 10 rpm to the value (f) measured at 30 rpm using a Brookfield viscometer.

The photosensitive conductive paste applied on the insulating layer and within the trench is exposed to light in alignment with the trench. Examples of exposure methods include proximity exposure through a photomask and direct patterning with laser light.

The opening width of the exposure mask during proximity exposure is preferably set to be equal to or less than the width of the trench in the insulating layer (top width c). This allows the formation of a circuit pattern with a higher aspect ratio.

The method for manufacturing a substrate with a circuit pattern of the present invention is suitable for manufacturing an inductor. That is, the method for manufacturing an inductor of the present invention includes the steps of manufacturing a substrate with a circuit pattern of the present invention.

The circuit patterned substrate obtained by the manufacturing method of the present invention is cut into desired chip sizes, sintered, coated with terminal electrodes, and subjected to plating treatment to obtain a multilayer chip inductor. Examples of cutting equipment include die saws and laser saws.

Sintering can make the circuit pattern conductive, creating a conductive pattern. Examples of coating methods for terminal electrodes include sputtering. Examples of metals used in the plating process include nickel and tin. [Example]

The present invention is further described in detail with the following embodiments and comparative examples. However, the present invention is not limited to the embodiments shown here.

[Measurement and Evaluation Method] (1) Median Diameter Measured by laser light scattering method using a particle size distribution measuring device ("Microtrac" HRA Model No. 9320-X100 manufactured by Nikkiso Co., Ltd.).

(2) High-precision pattern processing (formation of insulating ceramic layer) 100 parts by volume of "Pal Serum" BT149 (manufactured by Nippon Chemical Industry Co., Ltd.) as insulating ceramic powder, 240 parts by volume of polyvinyl butyral resin (SP value 19.1 (J/ ^cm3 ) ^1/2 ) as binder resin, 80 parts by volume of dibutyl phthalate as plasticizer, and 160 parts by volume of ethylene glycol monobutyl ether as solvent were mixed and coated on an alumina substrate (100 mm × 100 mm × thickness 0.5 mm) by a doctor blade method to form an insulating ceramic layer.

(Coating Film Formation) The photosensitive conductive paste obtained in Examples and Comparative Examples was applied to the insulating ceramic layer using screen printing to a film thickness of 10 μm after drying, forming a coating film.

(Dry Film Formation) The resulting coated film was dried in a hot air dryer at 80°C for 10 minutes to form a dry film on the insulating ceramic layer. This process was repeated to prepare four substrates each with dry films and insulating ceramic layers for each of the Examples and Comparative Examples.

(Pattern Formation) Four exposure masks with line widths/line spacings (hereinafter referred to as "L/S") of 20μm/20μm, 18μm/18μm, 15μm/15μm, and 12μm/12μm, respectively, were used on the aforementioned dry film. Exposure was performed at an irradiation dose of 400mJ/ ^cm² (at a wavelength of 365nm) using an ultra-high-pressure mercury lamp with an output of 21mW/ ^cm² .

Thereafter, shower development was performed using a 0.1 mass % sodium carbonate aqueous solution as a developer until the non-exposed portion was completely dissolved (hereinafter referred to as the "total dissolution time"), thereby producing four types of patterned sheets with different L/S ratios.

Each of the four patterned sheets was observed under an optical microscope at 10x magnification and evaluated based on the following criteria for pattern peeling or shorting. A score of D or higher was considered acceptable. A: No peeling or shorting was observed in all four pattern sizes. B: No peeling or shorting was observed in patterns larger than 15μm/15μm, but peeling or shorting was observed in patterns smaller than 12μm/12μm. C: No peeling or shorting was observed in patterns larger than 18μm/18μm, but peeling or shorting was observed in patterns smaller than 15μm/15μm. D: No peeling or shorting was observed in patterns larger than 20μm/20μm, but peeling or shorting was observed in patterns smaller than 18μm/18μm. E: Peeling or shorting was observed in all four sizes.

(3) Volume Resistivity The photosensitive conductive paste obtained in each Example and Comparative Example was applied to an alumina substrate (100 mm × 100 mm × 0.5 mm thick) by screen printing to a film thickness of 10 μm after drying. The resulting coated film was dried in a hot air dryer at 80°C for 10 minutes to obtain a dried film.

Except for using an exposure mask with a specified pattern (5cm long x 1mm line width, with 1cm square pads at both ends), exposure and development were performed in the same manner as described for the "High-precision Patterning Processability" method to obtain a patterned sheet for resistance measurement.

The obtained resistance measurement pattern-formed sheet was heat-treated at 880°C for 10 minutes and sintered to obtain a resistance measurement pattern-formed sintered body.

The resulting sintered body formed with a resistance measurement pattern was observed under an optical microscope at 1000x magnification to measure the line width of the sintered body. The film thickness of the sintered body was measured using a probe gauge ("SURFCOM" (registered trademark) 1400; manufactured by Tokyo Seimitsu Co., Ltd.). Furthermore, the resistance of the sintered body with the resistance measurement pattern was measured using a digital multimeter (CDM-16D; manufactured by CUSTOM Co., Ltd.). The volume resistivity was calculated using the following formula: Volume resistivity (μΩ·cm) = Actual resistance (Ω) × 10 ⁶ × Pattern line width (cm) × Pattern thickness (cm) ÷ Pattern length (cm) (formula).

Evaluation was conducted based on the following criteria, with a score of C or higher considered acceptable. A: Volume resistivity less than 2.2 μΩ·cm. B: Volume resistivity of 2.2 μΩ·cm or higher and less than 2.5 μΩ·cm. C: Volume resistivity of 2.5 μΩ·cm or higher and less than 3.0 μΩ·cm. D: Volume resistivity of 3.0 μΩ·cm or higher.

(4) Sintering Shrinkage The photosensitive conductive paste obtained in each Example and Comparative Example was applied to an alumina substrate (100 mm × 100 mm × 0.5 mm thick) by screen printing to a film thickness of 10 μm after drying. The resulting coated film was dried in a hot air dryer at 80°C for 10 minutes to obtain a dried film.

Using a mask with a coil pattern L/S of 20μm/20μm, exposure and development were performed in the same manner as in the "High-definition Pattern Processability" section above to obtain a patterned sheet for shrinkage measurement.

The resulting shrinkage measurement patterned sheet was observed under an optical microscope at 1000x magnification to measure the line width of the pattern before sintering. Furthermore, the film thickness of the pattern before sintering was measured using a stylus gauge ("SURFCOM" (registered trademark) 1400; manufactured by Tokyo Seimitsu Co., Ltd.).

Thereafter, the sheet having the pattern formed thereon for measuring shrinkage was sintered by heat treatment at 880°C for 10 minutes to obtain a sintered body having the pattern formed thereon for measuring shrinkage.

The resulting sintered product, formed using a pattern for shrinkage measurement, was observed under an optical microscope at 1000x magnification to measure the line width of the pattern after sintering. Furthermore, the film thickness of the pattern after sintering was measured using a stylus gauge ("SURFCOM" (registered trademark) 1400; manufactured by Tokyo Seimitsu Co., Ltd.). The sintering shrinkage was calculated using the following formula. Line width variation (%) = [Line width after sintering (μm) / Line width before sintering (μm)] × 100 Film thickness variation (%) = [Film thickness after sintering (μm) / Film thickness before sintering (μm)] × 100 Sintering shrinkage (%) = 100 - (Line width variation (%) × Film thickness variation (%)) / 100.

Evaluation was based on the following criteria, with a score of D or higher considered acceptable. A: Sintering shrinkage less than 55.0%. B: Sintering shrinkage of 55.0% or more and less than 58.0%. C: Sintering shrinkage of 58.0% or more and less than 60.0%. D: Sintering shrinkage of 60.0% or more and less than 63.0%. E: Sintering shrinkage of 63.0% or more.

(5) Observation and Evaluation of Circuit Pattern Cross-Sections The cross-sections of the circuit patterned substrates obtained in Examples 16 to 20 and Comparative Examples 5 and 6 were cut in the direction of the line width of the circuit pattern. The cross-sections were observed at a magnification of 3000 times using a scanning electron microscope (S2400; manufactured by Hitachi, Ltd.). The thickness of the insulating layer, the top width c and bottom width d of the trench, and the gap between the circuit pattern and the insulating layer were observed. The cross-sections of the trenches at 10 different locations were observed, and the number of cross-sections with gaps of 5 μm or more was evaluated as a score. Three or fewer cross-sections were considered acceptable. The size of the gap is calculated by measuring the longest part of the gap (the distance between the two ends of the gap that are farthest apart).

(6) Evaluation of the aspect ratio and resistance value of the conductive pattern A substrate was prepared using the same method as in Examples 16 to 20 and Comparative Examples 5 and 6, except that the length of the trenches in the insulating layer and the circuit pattern was set to 40 mm. The resulting substrate with the circuit pattern was sintered by heat treatment at 880°C for 10 minutes to obtain a conductive pattern. The resistance value of the conductive pattern was measured using a digital multimeter (CDM-16D; manufactured by CUSTOM). Next, the conductive pattern was cut in the direction of line width. The cross section was observed at a magnification of 3000 times using a scanning electron microscope (S2400; manufactured by Hitachi, Ltd.), and the line width and height of the conductive pattern were measured. The line width was set as the maximum width of the cross section of the conductive pattern. From the results, calculate the sheet resistance and the conductive pattern aspect ratio. Sheet resistance is calculated using the following formula: Sheet resistance (mΩ) = Conductive pattern resistance (mΩ) × Line width (mm) ÷ Conductive pattern length (mm) A value less than 3.5 mΩ is considered acceptable.

(Photosensitive Conductive Paste) The raw materials used in photosensitive conductive paste are as follows.

Conductive Particles (A) A-1: Ag powder with a median diameter r of 3.2 μm and a density of 10.5 g/cm ^3. A-2: Ag powder with an r of 4.5 μm and a density of 10.5 g/cm ^3. A-3: Ag powder with an r of 5.2 μm and a density of 10.5 g/cm ^3. A-4: Ag powder with an r of 5.8 μm and a density of 10.5 g/cm ^3. A-5: Ag powder with an r of 2.8 μm and a density of 10.5 g/cm ^3. A-6: Ag powder with an r of 6.5 μm and a density of 10.5 g/cm ³ .

Alkali-soluble resin: Acrylic resin (weight-average molecular weight 30,000, glass transition point 110°C, acid value 100 mgKOH/g, density 1.0 g/cm ³ ) prepared by the addition reaction of 40 mol parts of epoxypropyl methacrylate to 100 mol parts of the carboxyl groups of a copolymer of methacrylic acid/methyl methacrylate/styrene (molar ratio 54/23/23).

Photosensitive monomer: Urethane acrylate containing an ester structure ("NK OLIGO" UA-122P manufactured by Shin-Nakamura Chemical Industry Co., Ltd., viscosity 7.0 Pa·s, weight-average molecular weight 1,100, density 1.0 g/cm ³ ).

Photopolymerization initiator: oxime-based photopolymerization initiator ("ADEKA OPTOMER" N-1919 manufactured by ADEKA Co., Ltd., density 1.3 g/cm ³ ).

Leveling agent: "DISPARLON" (registered trademark) L-1980N (density 1.0 g/cm ³ ; manufactured by Kusumoto Chemicals Co., Ltd.).

Dispersant: "FLOWLEN" G-700 (density 1.1 g/cm ³ ; manufactured by Kyoeisha Chemical Co., Ltd.).

Solvent: CELTOL CHXA (cyclohexanol acetate, density 1.0 g/cm ³ ; manufactured by Daicel Co., Ltd.).

Inorganic particles (C) C-1: Silicon oxide ("AEROSIL" R972 manufactured by Nippon Aerosil Co., Ltd., median diameter 12 nm, density 2.2 g/cm ³ ) C-2: Aluminum oxide ("AEROXIDE" AluC manufactured by Nippon Aerosil Co., Ltd., median diameter 13 nm, density 3.3 g/cm ³ ).

[Example 1] 5.0 g of alkali-soluble resin, 2.4 g of NK OLIGOUA-122P, 0.5 g of ADEKA OPTOMERN-1919, 0.1 g of DISPARLON L-1980N, 0.1 g of FLOWLENG-700, and 11.9 g of CELTOL CHXA were mixed to obtain 20.0 g of photosensitive organic component B-1 (specific gravity 1.0 g/cm ³ ). The composition is shown in Table 1.

20.0 g of the resulting photosensitive organic component (B-1) was mixed with 51.8 g of Ag powder (A-3) and 0.5 g of inorganic particles (C-1) and kneaded using a three-roll mill to obtain the photosensitive conductive paste P-1 shown in Table 2. The evaluation results are shown in Table 2.

[Examples 2-15, Comparative Examples 1-4] Photosensitive conductive pastes P-2 to P-19 having the compositions shown in Tables 2-4 were prepared using the same method as in Example 1.

Evaluation of high-definition pattern processability: Example 4 exhibited peeling only in patterns with a size of 12μm/12μm. Example 5 exhibited peeling only in patterns with a size of 15μm/15μm or less. Example 6 exhibited shorting only in patterns with a size of 12μm/12μm or less. Example 7 exhibited shorting only in patterns with a size of 15μm/15μm or less. Example 8 exhibited peeling only in patterns with a size of 15μm/15μm or less. Example 13 exhibited peeling only in patterns with a size of 15μm/15μm or less. In Example 14, peeling was observed only in patterns smaller than 15μm/15μm. In Example 15, peeling was observed only in patterns smaller than 18μm/18μm. In Comparative Example 2, peeling was observed in all four pattern sizes. In Comparative Example 3, peeling was observed only in patterns smaller than 18μm/18μm. In Comparative Example 4, short circuiting was observed in all four pattern sizes.

The evaluation results are shown in Tables 2 to 4.

[Examples 16-20, Comparative Examples 5 and 6] (Base material)

Alumina plate is used as the base material.

(Photosensitive insulating composition)

55 parts by mass of insulating ceramic powder (L5 manufactured by Ferro Corp.), 20 parts by mass of an acrylic resin (weight average molecular weight 30,000, glass transition point 110°C, acid value 100 mgKOH/g) prepared by addition reaction of 40 parts by mass of epoxypropyl methacrylate to 100 parts by mass of the carboxyl groups of a copolymer of methacrylic acid/methyl methacrylate/styrene in a molar ratio of 54/23/23) as an alkali-soluble resin, and 20 parts by mass of a photopolymerization initiator ("ADEKA 7.0 parts by mass of OPTOMER ("N-1919" manufactured by Kusumoto Chemicals), 1.0 part by mass of a leveling agent ("DISPARLON" L-1980N manufactured by Kusumoto Chemicals), 1.0 part by mass of a dispersant ("FLOWLEN" G-700 manufactured by Kyoeisha Chemicals), 4.0 parts by mass of dibutyl phthalate as a plasticizer, and 12.0 parts by mass of a solvent ("CELTOL" CHXA manufactured by Daicel Co., Ltd.) were mixed and kneaded using a three-roll mill to obtain a photosensitive insulating composition I-1.

(Photosensitive conductive paste)

Use photosensitive conductive paste P-3.

(Circuit pattern attached to substrate)

The photosensitive insulating composition I-1 was applied to the substrate to obtain the insulating layer thickness shown in Table 5 and dried.

Next, an exposure mask was placed above the coating of the photosensitive insulating composition at the intervals shown in Table 5, and full-line exposure was performed using an exposure device at the exposure dose shown in Table 5.

Next, the substrate was immersed in a 0.2 mass% Na ₂ CO ₃ solution for the time shown in Table 5, thereby performing development.

Next, the cleaning process is carried out using ultrapure water.

Next, a photosensitive conductive paste was applied to the insulating layer with the trenches to achieve the maximum coating thickness shown in Table 5 (the distance from the bottom of the trench in the insulating layer, where the photosensitive conductive paste had penetrated, to the surface of the photosensitive conductive paste coating, which roughly corresponds to the height of the circuit pattern). The coating was then dried.

Next, a photomask having an opening width shown in Table 5 was placed above the coating of the photosensitive conductive composition, and the portion corresponding to the trench of the insulating layer was exposed using an exposure device at an exposure dose of 400 mJ/cm ² (at a wavelength of 365 nm).

Next, the substrate was immersed in a 0.2 mass% Na ₂ CO ₃ solution for 30 seconds to perform development.

Next, the substrate is cleaned with ultrapure water to obtain a substrate with a circuit pattern.

[Table 1] [Table 1] Photosensitive organic ingredient B-1 Volume% Mass% Composition Alkaline soluble resin 25.0 24.8 Photosensitive monomer 12.0 11.9 Photopolymerization initiator 2.0 2.6 Equalizer 0.5 0.5 dispersants 0.5 0.6 solvent 60.0 59.6

[Table 2] [Table 2] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Photosensitive conductive paste P-1 P-2 P-3 P-4 P-5 P-6 P-7 P-8 Conductive particles (A) A-2 A-2 A-2 A-2 A-1 A-3 A-4 A-1 Photosensitive organic ingredient (B) B-1 B-1 B-1 B-1 B-1 B-1 B-1 B-1 Inorganic particles (C) C-1 C-1 C-1 C-1 C-1 C-1 C-1 C-1 Paste composition ratio [mass %] Conductive particles (A) 71.5 74.1 76.9 81.6 76.8 76.9 76.9 76.9 Inorganic particles (C) 0.7 0.7 0.7 0.8 0.5 0.8 0.9 0.7 Photosensitive organic ingredient (B) Solid ingredients (excluding solvent) 11.2 10.2 9.1 7.1 9.1 9.0 9.0 9.1 solvent 16.6 15.0 13.4 10.5 13.5 13.3 13.2 13.4 Paste composition ratio [volume %] Conductive powder(A) 19.6 21.8 24.5 30.3 24.3 24.5 24.6 24.5 Inorganic particles (C) 0.9 1.0 1.1 1.4 0.8 1.3 1.4 1.1 Photosensitive organic ingredient (B) Solid ingredients (excluding solvent) 31.8 30.9 29.8 27.3 30.0 29.7 29.6 29.8 solvent 47.7 46.3 44.7 41.0 44.9 44.5 44.4 44.7 Median diameter r of conductive particles (A) [μm] 4.5 4.5 4.5 4.5 3.2 5.2 5.8 3.2 Volume fraction of conductive particles (A) in the total solid content V ₁ [volume %] 37.5 40.6 44.2 51.4 44.2 44.2 44.2 44.2 Volume ratio of inorganic particles (B) to 100 volume % of conductive particles (A) V ₂ [volume %] 4.3 4.3 4.3 4.3 4.3 4.3 4.3 2.7 r×V ₁ ×V ₂ 726 786 855 995 608 988 1102 382 Evaluation results High-precision pattern processing A A A B C B C C Volume resistivity [μΩ・cm] A(2.1) A(2.0) A(2.0) A(2.0) A(2.0) B(2.3) B(2.4) A(2.0) Sintering shrinkage [%] B(57.8) B(56.5) A(54.8) A(46.9) C(58.3) A(53.8) A(52.5) D(60.1)

[Table 3] [Table 3] Example 9 Example 10 Example 11 Example 12 Example 13 Example 14 Example 15 Photosensitive conductive paste P-9 P-10 P-11 P-12 P-13 P-14 P-15 Conductive particles (A) A-2 A-2 A-2 A-2 A-1 A-1 A-1 Photosensitive organic ingredient (B) B-1 B-1 B-1 B-1 B-1 B-1 B-1 Inorganic particles (C) C-1 C-1 C-1 C-1 C-1 C-1 C-2 Paste composition ratio [mass %] Conductive particles (A) 76.9 76.9 76.9 76.9 76.9 71.5 71.3 Inorganic particles (C) 0.7 0.7 0.7 0.7 0.7 0.5 0.7 Photosensitive organic ingredient (B) Solid ingredients (excluding solvent) 9.1 9.1 9.1 9.1 9.1 11.3 11.3 solvent 13.4 13.4 13.4 13.4 13.4 16.7 16.7 Paste composition ratio [volume %] Conductive particles (A) 24.5 24.5 24.5 24.5 24.5 19.5 19.5 Inorganic particles (C) 1.1 1.1 1.1 1.1 1.1 0.6 0.6 Photosensitive organic ingredient (B) Solid ingredients (excluding solvent) 29.8 29.8 29.8 29.8 29.8 31.9 31.9 solvent 44.7 44.7 44.7 44.7 44.7 47.9 47.9 Median diameter r of conductive particles (A) [μm] 4.5 4.5 4.5 4.5 3.2 3.2 3.2 Volume fraction of conductive particles (A) in the total solid content V ₁ [volume %] 44.2 44.2 44.2 44.2 44.2 37.5 37.5 Volume ratio of inorganic particles (B) to 100 volume % of conductive particles (A) V ₂ [volume %] 3.1 3.6 6.0 8.5 11 2.7 2.7 r×V ₁ ×V ₂ 617 716 1193 1691 1556 324 324 Evaluation results High-precision pattern processing A A A A C C D Volume resistivity [μΩ・cm] A(2.0) A(2.0) B(2.3) B(2.4) C(2.9) B(2.2) B(2.2) Sintering shrinkage [%] B(56.4) B(55.3) A(54.0) A(53.2) A(52.7) D(62.8) D(62.9)

[Table 4] [Table 4] Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Photosensitive conductive paste P-16 P-17 P-18 P-19 Conductive particles (A) A-2 A-2 A-5 A-6 Photosensitive organic ingredient (B) B-1 B-1 B-1 B-1 Inorganic particles (C) C-1 C-1 C-1 C-1 Paste composition ratio [mass %] Conductive particles (A) 69.4 85.8 76.8 76.9 Inorganic particles (C) 0.7 0.8 0.5 1.0 Photosensitive organic ingredient (B) Solid ingredients (excluding solvent) 12.1 5.4 9.2 8.9 solvent 17.9 8.0 13.5 13.2 Paste composition ratio [volume %] Conductive particles (A) 18.0 37.4 24.3 24.6 Inorganic particles (C) 0.8 1.7 0.7 1.6 Photosensitive organic ingredient (B) Solid ingredients (excluding solvent) 32.5 24.4 30.0 29.5 solvent 48.7 36.6 45.0 44.3 Median diameter r of conductive particles (A) [μm] 4.5 4.5 2.8 6.5 Volume fraction of conductive particles (A) in the total solid content V ₁ [volume %] 35.1 58.9 44.2 44.2 Volume ratio of inorganic particles (B) to 100 volume % of conductive particles (A) V ₂ [volume %] 4.3 4.3 4.3 4.3 r×V ₁ ×V ₂ 679 1140 532 1235 Evaluation results High-precision pattern processing A E D E Volume resistivity [μΩ・cm] B(2.2) A(2.0) A(2.0) D(3.4) Sintering shrinkage [%] E(63.5) - E(63.4) -

[Table 5] [Table 5] Formation conditions of the insulating layer Circuit pattern formation conditions Observation of circuit pattern cross-section Evaluation of conductive patterns Gap between coating and mask Exposure Development time Photosensitive conductive paste Maximum coating thickness Mask opening width Layer thickness Top width c Bottom width d d/c gap Width of conductive pattern Conductive pattern aspect ratio Chip resistance μm mJ/cm ² Second - μm μm μm μm μm - Score μm - mΩ Example 16 100 100 60 P-3 15.0 20.0 10.0 20.0 15.0 0.75 0 12.0 0.75 2.54 Example 17 75 100 60 P-3 15.0 20.0 10.0 20.0 17.9 0.90 0 12.0 0.75 2.35 Example 18 50 100 60 P-3 15.0 20.0 10.0 20.0 19.0 0.95 1 12.0 0.75 2.90 Example 19 30 100 60 P-3 15.0 20.0 10.0 20.0 19.5 0.98 2 12.0 0.75 2.98 Example 20 300 100 60 P-3 15.0 20.0 10.0 20.0 10.0 0.50 0 12.0 0.75 2.96 Comparative example 5 0 100 120 P-3 10.0 20.0 10.0 20.0 20.0 1.00 10 12.0 0.50 4.20 Comparative example 6 0 170 180 P-3 20.0 20.0 20.0 20.0 20.0 1.00 10 12.0 1.00 3.70

without.

without.

Claims (14)

A photosensitive conductive paste comprises conductive particles (A), a photosensitive organic component (B), and inorganic particles (C) other than the conductive particles (A). The conductive particles (A) have a median diameter r of 3.0 μm or more and 6.0 μm or less in particle size distribution, a content _V1 of the conductive particles (A) in the total solids content of 37 volume % or more and 55 volume % or less, a median diameter of the inorganic particles (C) of 1 to 100 nm in particle size distribution, an amount _V2 of the inorganic particles (C) per 100 volume % of the conductive particles (A) of 3 volume % or more and 10 volume % or less, and a product of r, _V1 , and _V2 (r× _V1 ×V2 ₎ of 500 or more and 3300 or less. The photosensitive conductive paste of claim 1, wherein the inorganic particles (C) contain at least one selected from the group consisting of titanium oxide, aluminum oxide, silicon oxide, cordierite, andalusite, spinel, and barium titanium oxide. A cured product obtained by curing the photosensitive conductive paste according to claim 1 or 2. For the cured product of claim 3, the film thickness t is not less than 10μm and not more than 35μm. For the cured product of claim 3 or 4, the ratio of film thickness t to line width w (t/w) is not less than 0.5 and not more than 1.0. The hardened article of claim 3 or 4, wherein the ratio b/a of the bottom width b to the top width a is not less than 0.6 and not more than 1.0. A method for manufacturing an insulating ceramic layer with a circuit pattern comprises: applying the photosensitive conductive paste of claim 1 or 2 onto the insulating ceramic layer to obtain a coating film; drying the coating film to obtain a dried film; and exposing and developing the dried film to obtain a circuit pattern. A method for manufacturing an electronic component comprises: a step of obtaining a plurality of insulating ceramic layers with a circuit pattern by the method for manufacturing an insulating ceramic layer with a circuit pattern as claimed in claim 7; a step of laminating and hot-pressing the plurality of insulating ceramic layers with a circuit pattern to obtain a laminate; and a step of sintering the laminate. A method for manufacturing an electronic component, comprising: a step of obtaining a laminate by sequentially repeating the following steps A to F multiple times on an insulating ceramic layer with a circuit pattern obtained by the method for manufacturing an insulating ceramic layer with a circuit pattern as claimed in claim 7, and a step of sintering the laminate; step A: a step of applying a photosensitive insulating ceramic composition to obtain a coating film, step B: a step of applying a photosensitive insulating ceramic composition to a laminate; The coating film is dried to obtain a dry film. Step C: exposing and developing the dry film to obtain an insulating ceramic layer. Step D: applying the photosensitive conductive paste of claim 1 or 2 on the insulating ceramic layer to obtain a coating film. Step E: drying the coating film to obtain a dry film. Step F: exposing and developing the dry film to obtain a circuit pattern. A method for manufacturing a substrate with a circuit pattern, characterized by comprising the steps of: coating a photosensitive insulating ceramic composition on a substrate; exposing the coating of the photosensitive insulating ceramic composition to a desired pattern; and developing the exposed coating of the photosensitive insulating ceramic composition to form an insulating layer having grooves. , applying the photosensitive conductive paste of claim 1 or 2 on the insulating layer and in the trench, exposing the photosensitive conductive paste film corresponding to the trench, and developing the exposed photosensitive conductive paste film to form a circuit pattern at a position corresponding to the trench; the trench has a pyramidal shape on the side. The method for manufacturing a circuit pattern-attached substrate of claim 10, wherein in the trench, the ratio d/c of the bottom width d relative to the top width c is greater than or equal to 0.30 and less than 1.00. In the method for manufacturing a substrate with a circuit pattern according to claim 10 or 11, the viscosity of the photosensitive conductive paste in the step of applying the photosensitive conductive paste on the insulating layer and in the trench is 3-50 Pa·s. The method for manufacturing a circuit patterned substrate according to claim 10 or 11, wherein in the step of exposing the coating of the photosensitive conductive paste, the exposure is performed through an exposure mask having an opening width narrower than the top width A of the trench of the insulating layer. A method for manufacturing an inductor, characterized by comprising the steps of manufacturing a substrate with a circuit pattern as described in any one of claims 10 to 13.