WO2023157941A1 - Conductive paste and multilayer substrate - Google Patents

Conductive paste and multilayer substrate Download PDF

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Publication number
WO2023157941A1
WO2023157941A1 PCT/JP2023/005640 JP2023005640W WO2023157941A1 WO 2023157941 A1 WO2023157941 A1 WO 2023157941A1 JP 2023005640 W JP2023005640 W JP 2023005640W WO 2023157941 A1 WO2023157941 A1 WO 2023157941A1
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WIPO (PCT)
Prior art keywords
metal particles
mass
melting point
parts
conductive paste
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PCT/JP2023/005640
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French (fr)
Japanese (ja)
Inventor
元 中園
剛志 津田
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タツタ電線株式会社
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Publication of WO2023157941A1 publication Critical patent/WO2023157941A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L63/00—Compositions of epoxy resins; Compositions of derivatives of epoxy resins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/20—Conductive material dispersed in non-conductive organic material
    • H01B1/22—Conductive material dispersed in non-conductive organic material the conductive material comprising metals or alloys
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/09—Use of materials for the conductive, e.g. metallic pattern

Definitions

  • the present invention relates to a conductive paste and a multilayer substrate using this conductive paste.
  • a conductive paste used for filling holes in substrates flux, curing agent, thermosetting resin, and conductive filler are added, and by heating under certain conditions, the resin hardens and the metal particles melt.
  • Metal melting pastes have been used which metallize (ie, form intermetallics between metal particles) by heating.
  • Patent Documents 1 and 2 In order to exhibit long-term connection stability in such a conductive paste, a method of using a conductive filler in combination with high-melting metal particles and low-melting metal particles has been known (Patent Documents 1 and 2). .
  • Patent Document 3 In addition, in order to improve conductivity, an invention has been reported in which a fluorine-based surfactant is used to improve the wettability of a conductive paste and improve connectivity (Patent Document 3).
  • An object of the present invention is to solve such problems, and to provide a conductive paste capable of forming a cured product that achieves both high conductivity and long-term reliability.
  • the material has high conductivity and long-term reliability.
  • the present invention has been completed based on these findings.
  • the present invention provides high melting point metal particles (B1) containing silver and/or copper and having a melting point of 800° C. or higher and a low melting point metal alloy having a melting point of 130° C. to 150° C. per 100 parts by mass of a liquid epoxy compound.
  • a conductive paste containing 1700 to 3300 parts by mass of metal particles, 1 to 30 parts by mass of a curing agent, and 20 to 200 parts by mass of flux.
  • the conductive paste can contain a large amount of metal particles, and as a result, the conductivity can be improved.
  • the high-melting-point metal particles (B1) and the low-melting-point metal particles (B2) in combination the cured product has excellent conductivity.
  • the low-melting-point metal particles (B3) the long-term reliability of a cured product can be improved. Further, 1700 parts by weight of metal particles containing the high melting point metal particles (B1), the low melting point metal particles (B2), and the low melting point metal particles (B3) are added to 100 parts by mass of the liquid epoxy compound.
  • the cured product of the conductive paste By containing up to 3300 parts by weight, it is possible to reduce the specific resistance in the cured product of the conductive paste, improve the conductivity, and suppress the occurrence of cracks, thereby improving the long-term connection reliability.
  • the occurrence of cracks in the cured product By containing 1 part by mass to 30 parts by mass of the curing agent, the occurrence of cracks in the cured product can be suppressed, and long-term reliability can be improved.
  • the cured product of the conductive paste By containing 20 parts by mass to 200 parts by mass of flux, the cured product of the conductive paste can have a reduced specific resistance and an improved electrical conductivity.
  • the mass ratio of the low-melting-point metal particles (B2) and the low-melting-point metal particles (B3) is 0.9 or more, the specific resistance tends to be reduced and the conductivity tends to be excellent. Further, when the mass ratio of the low-melting-point metal particles (B2) and the low-melting-point metal particles (B3) is 40 or less, crack generation can be suppressed and long-term connection reliability can be easily achieved. Become.
  • the curing agent is preferably a hydroxyl group-containing aromatic compound.
  • the curing agent is preferably a phenol-based curing agent and/or a naphthol-based curing agent.
  • the present invention comprises a plurality of conductive layers and an insulating layer interposed between the plurality of conductive layers, holes penetrating the insulating layers are filled with a cured product of the conductive paste of the present invention, and the conductive paste A multilayer substrate in which conductive layers in contact with both surfaces of the insulating layer are electrically connected to each other through the cured product of (1).
  • the high-melting metal particles (B1), the low-melting metal particles (B2), and the low-melting metal particles (B3) are melted and integrated with each other to form an alloy. is preferred.
  • the conductive paste of the present invention can form a cured product that achieves both high conductivity and long-term reliability.
  • the conductive paste of the present invention contains at least a liquid epoxy compound, metal particles, a curing agent and flux.
  • the conductive paste may contain components other than the components described above.
  • the liquid epoxy compound is a compound having at least one epoxy group (oxiranyl group) in the molecule (in one molecule).
  • the liquid epoxy compound means an epoxy compound that is liquid at room temperature.
  • liquid at room temperature shall mean that it is in a state of exhibiting fluidity at 25°C in the absence of a solvent. Since the conductive paste of the present invention contains the liquid epoxy compound having high fluidity, a large amount of metal particles can be blended, and as a result, the conductivity can be improved. Only one kind of the liquid epoxy compound may be used, or two or more kinds thereof may be used.
  • liquid epoxy compound examples include, but are not limited to, bisphenol-type epoxy compounds, spirocyclic-type epoxy compounds, naphthalene-type epoxy compounds, biphenyl-type epoxy compounds, terpene-type epoxy compounds, novolak-type epoxy compounds, and dimer acid-modified epoxy compounds. , glycidylamine-type epoxy compounds, glycidyl ether-type epoxy compounds, rubber-modified epoxy resins, chelate-modified epoxy resins, and the like. Among them, a dimer acid-modified epoxy compound is preferable from the viewpoint of low resistance and excellent storage stability.
  • bisphenol-type epoxy compounds examples include bisphenol A-type epoxy compounds, bisphenol F-type epoxy compounds, bisphenol S-type epoxy compounds, tetrabromobisphenol A-type epoxy compounds, and the like.
  • novolak-type epoxy compounds examples include cresol novolak-type epoxy compounds, phenol novolak-type epoxy compounds, ⁇ -naphthol novolak-type epoxy compounds, and brominated phenol novolac-type epoxy compounds.
  • the dimer acid-modified epoxy compound is an epoxy compound modified with dimer acid, that is, a reaction of at least one carboxyl group in the dimer acid structure with a polyfunctional epoxy compound.
  • a dimer acid is a dimer of an unsaturated fatty acid here.
  • the unsaturated fatty acid used as the raw material is not particularly limited, but for example, plant-derived fats and oils mainly composed of unsaturated fatty acids having 18 carbon atoms such as oleic acid and linoleic acid can be used.
  • the structure of the dimer acid may be either cyclic or non-cyclic.
  • the epoxy compound that undergoes dimer acid modification is not particularly limited, but includes, for example, the epoxy compounds exemplified as the above epoxy compounds.
  • Epoxy compounds contained in the dimer acid-modified epoxy compound may be used alone or in combination of two or more.
  • known dimer acid-modified epoxy compounds obtained by modifying various epoxy compounds such as bisphenol type, ether ester type, novolac epoxy type, ester type, aliphatic type, and aromatic type with dimer acid can be used.
  • glycidylamine-type epoxy compounds examples include aminophenol-type epoxy compounds such as tetraglycidyldiaminodiphenylmethane and N,N-bis(2,3-epoxypropyl)-4-(2,3-epoxypropoxy)aniline. mentioned.
  • glycidyl ether-type epoxy compounds examples include tris(glycidyloxyphenyl)methane, tetrakis(glycidyloxyphenyl)ethane, and glycidyl alkyl ethers.
  • the rubber-modified epoxy resin contains a rubber component in the epoxy resin.
  • the rubber component include butadiene rubber, acrylic rubber, silicone rubber, butyl rubber, isoprene rubber, styrene rubber, chloroprene rubber, NBR, SBR, IR, and EPR. Only one type of the rubber component may be used, or two or more types may be used.
  • metal particles In the conductive paste of the present invention, as metal particles, high-melting-point metal particles (B1) containing silver and/or copper and having a melting point of 800° C. or higher and low-melting-point metal particles (B2) being an alloy having a melting point of 130° C. to 150° C. and low-melting-point metal particles (B3) having a melting point of 200° C. to 240° C., which is an alloy of two or more selected from the group consisting of tin, silver, copper, bismuth, and indium.
  • the high melting point metal particles (B1) are metal particles containing copper (melting point: 1083°C) and/or silver (melting point: 961°C).
  • the conductive paste of the present invention can exhibit sufficient conductivity by combining the high melting point metal particles (B1) and the low melting point metal particles (B2).
  • the high melting point metal particles (B1) may contain metals other than copper and silver, such as gold (melting point: 1064°C), nickel (melting point: 1455°C), zinc (melting point: 420°C) , or an alloy containing one or more of these and having a melting point of 800° C. or higher.
  • the high-melting-point metal particles (B1) only one type may be used, or two or more types may be used.
  • the high-melting-point metal particles (B1) may be metal-coated metal particles, such as silver-coated copper particles, gold-coated copper particles, silver-coated nickel particles, or silver-coated alloy particles.
  • metal-coated metal particles such as silver-coated copper particles, gold-coated copper particles, silver-coated nickel particles, or silver-coated alloy particles.
  • silver-coated alloy particles include silver-coated copper alloy particles in which an alloy containing copper (for example, a copper alloy comprising an alloy of copper, nickel and zinc) is coated with silver.
  • the melting point of the high melting point metal particles (B1) is 800°C or higher, preferably 900°C or higher, more preferably 1000°C or higher.
  • the melting point of the high-melting-point metal particles (B1) is preferably 1300° C. or lower, more preferably 1200° C. or lower.
  • the conductive paste tends to be easily alloyed when cured.
  • the content of the high-melting-point metal particles (B1) is preferably 400 parts by mass to 1800 parts by mass, more preferably 500 parts by mass to 1500 parts by mass, based on 100 parts by mass of the liquid epoxy compound. It is preferably from 600 parts by mass to 1400 parts by mass, and particularly preferably from 700 parts by mass to 1300 parts by mass.
  • 400 parts by mass or more of the high-melting-point metal particles (B1) with respect to 100 parts by mass of the liquid epoxy compound the specific resistance of the cured product can be lowered, and sufficient conductivity can be exhibited. easier.
  • the content of the high-melting-point metal particles (B1) is 1800 parts by mass or less, it is possible to improve the long-term reliability by suppressing the occurrence of cracks when the cured product is made into a cured product. can.
  • the low-melting-point metal particles (B2) are metal particles that are an alloy with a melting point of 130.degree. C. to 150.degree.
  • the conductive paste of the present invention can exhibit sufficient conductivity by combining the high melting point metal particles (B1) and the low melting point metal particles (B2).
  • As the low-melting-point metal particles (B2) only one type may be used, or two or more types may be used.
  • the low-melting-point metal particles (B2) are preferably an alloy containing tin (melting point: 232°C) and bismuth (melting point: 271°C). Other metals may be contained if appropriate. Further, the mass ratio of tin:bismuth in the low melting point metal particles (B2) is preferably 80:20 to 40:60. By setting the mass ratio of tin to bismuth as described above, it becomes easy to set the melting point of the melting point metal particles (B2) within the range of 130°C to 150°C.
  • the melting point of the low melting point metal particles (B2) is 130°C to 150°C, preferably 135°C to 145°C. When the melting point is within the above range, it becomes easy to perform metallization during the curing reaction of the conductive paste.
  • the content of the low melting point metal particles (B2) is preferably 300 parts by mass to 2400 parts by mass, more preferably 400 parts by mass to 2300 parts by mass, based on 100 parts by mass of the liquid epoxy compound. It is preferably 500 to 2200 parts by mass, particularly preferably 600 to 2000 parts by mass.
  • the content of the low-melting-point metal particles (B2) is 300 parts by mass or more with respect to 100 parts by mass of the liquid epoxy compound, a cured product can exhibit sufficient conductivity.
  • the content of the low-melting-point metal particles (B2) is 2400 parts by mass or less, it is possible to improve the long-term reliability by suppressing the occurrence of cracks when the cured product is made into a cured product. can.
  • the low-melting-point metal particles (B3) are an alloy of two or more selected from the group consisting of tin, silver, copper, bismuth, and indium, and have a melting point of 200°C to 240°C.
  • the conductive paste of the present invention can improve the long-term reliability of the conductive paste by containing the low-melting-point metal particles (B3).
  • the low-melting-point metal particles (B3) only one kind may be used, or two or more kinds may be used.
  • the low-melting-point metal particles (B3) are preferably an alloy containing tin as a main component. Also, as long as the melting point is in the range of 200°C to 240°C, metals other than the metals mentioned above may be contained.
  • the content of tin is preferably 80% by mass or more, more preferably 85% by mass or more, and particularly preferably 90% by mass or more in the total amount (100% by mass) of the alloy.
  • the low-melting-point metal particles (B3) containing tin as a main component facilitates setting the melting point to 200°C to 240°C.
  • the melting point of the low melting point metal particles (B3) is 200°C to 240°C, preferably 205°C to 235°C.
  • the melting point of the low-melting-point metal particles (B3) is within the above range, long-term reliability can be easily improved.
  • the content of the low melting point metal particles (B3) is preferably 40 to 700 parts by mass, more preferably 50 to 600 parts by mass, and particularly preferably 100 parts by mass of the liquid epoxy compound. is 60 parts by mass to 500 parts by mass.
  • the content of the low-melting-point metal particles (B3) is 40 parts by mass or more with respect to 100 parts by mass of the liquid epoxy compound, long-term connection reliability can be improved when cured.
  • the content of the low-melting-point metal particles (B3) is 700 parts by mass or less, it is possible to exhibit appropriate filling properties.
  • the conductive paste of the present invention may contain metal particles other than the high melting point metal particles (B1), the low melting point metal particles (B2), and the low melting point metal particles (B3).
  • the high melting point metal particles (B1), the low melting point metal particles (B2), and the low melting point metal particles contained in the conductive paste The total amount of (B3) is preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably 99% by mass or more, based on the total amount (100% by mass) of the metal particles.
  • the shape of the metal particles includes spherical, flake-like (scale-like), dendritic, fibrous, amorphous (polyhedral), and the like.
  • the high-melting-point metal particles (B1), the low-melting-point metal particles (B2), and the low-melting-point metal particles (B3) may have different or identical particle shapes. Among them, a spherical shape is preferable from the viewpoint of higher filling properties, filling properties, and coating stability of the conductive paste and better conductivity.
  • the average particle size (D50) of the metal particles is 0.5 ⁇ m to 30 ⁇ m for each of the high melting point metal particles (B1), the low melting point metal particles (B2), and the low melting point metal particles (B3). preferably 1 ⁇ m to 10 ⁇ m.
  • the total amount of metal particles used in the conductive paste of the present invention is 1700 parts by mass to 3300 parts by mass, preferably 1800 parts by mass to 3200 parts by mass, relative to 100 parts by mass of the liquid epoxy compound. It is preferably 1900 parts by mass to 3000 parts by mass.
  • the content of the metal particles is 1700 parts by mass or more with respect to 100 parts by mass of the liquid epoxy compound, the specific resistance can be reduced and the conductivity can be improved when a cured product is obtained.
  • the content of the metal particles is 3300 parts by mass or less, it is possible to improve filling properties and improve long-term reliability.
  • the conductive paste has a mass ratio of 0.9 or more between the low-melting-point metal particles (B2) and the low-melting-point metal particles (B3). It tends to be able to achieve both long-term reliability while being excellent in performance.
  • the mass ratio of the low-melting-point metal particles (B2) and the low-melting-point metal particles (B3) is 40 or less, the cured product has sufficient reflow resistance and heat cycle resistance, and can be used for a long period of time. tend to be more reliable.
  • the curing agent preferably cures the liquid epoxy compound contained in the conductive paste of the present invention. Therefore, the curing agent preferably has a functional group reactive with an epoxy group. Only one kind of the curing agent may be used, or two or more kinds thereof may be used.
  • the curing agent examples include isocyanate-based curing agents, phenol-based curing agents, naphthol-based curing agents, imidazole-based curing agents, and amine-based curing agents.
  • the curing agent is preferably a hydroxyl group-containing aromatic compound from the viewpoint of reactivity with the epoxy compound.
  • Preferable examples of the hydroxyl-containing aromatic compound include phenol-based curing agents and naphthol-based curing agents.
  • phenol-based curing agent examples include a phenol-based curing agent having a novolac structure, a nitrogen-containing phenol-based curing agent, and a triazine skeleton-containing phenol-based curing agent.
  • Examples of the naphthol-based curing agent include a naphthol-based curing agent having a novolak structure, a nitrogen-containing naphthol-based curing agent, and a triazine skeleton-containing naphthol-based curing agent.
  • the content of the curing agent is 1 to 30 parts by mass, preferably 2 to 27 parts by mass, more preferably 3 to 25 parts by mass with respect to 100 parts by mass of the liquid epoxy compound.
  • the content is 1 part by mass or more, the curing of the curable compound in the conductive paste is sufficient, and long-term reliability tends to be excellent.
  • the content is 30 parts by mass or less, the curing agent does not hinder conduction in a cured product, and conductivity tends to be good.
  • the flux has a role of promoting metallization of the metal particles.
  • Examples of the flux include polyvalent carboxylic acid compounds and other compounds. Only one kind of flux may be used, or two or more kinds thereof may be used.
  • polyvalent carboxylic acid compounds examples include dicarboxylic acids such as oxalic acid, glutaric acid, adipic acid, succinic acid, sebacic acid, malonic acid, maleic acid, fumaric acid, phthalic acid, pimelic acid, suberic acid, and azelaic acid.
  • dicarboxylic acids such as oxalic acid, glutaric acid, adipic acid, succinic acid, sebacic acid, malonic acid, maleic acid, fumaric acid, phthalic acid, pimelic acid, suberic acid, and azelaic acid.
  • terephthalic acid citraconic acid, ⁇ -ketoglutaric acid, diglycolic acid, thiodiglycolic acid, dithiodiglycolic acid, 4-cyclohexene-1,2-dicarboxylic acid, dodecanedioic acid, diphenyl ether-4,4'-dicarboxylic acid , pyridine-2,6-dicarboxylic acid, tetrahydrocarboxylic acid, hexahydrocarboxylic acid, tetrahydrophthalic acid, hexahydrophthalic acid, 8-ethyloctadecanedioic acid, etc.
  • Tricarboxylic acids include, for example, trimellitic acid, citric acid, acid, isocitric acid, butane-1,2,4-tricarboxylic acid, cyclohexane-1,2,4-tricarboxylic acid, benzene-1,2,4-tricarboxylic acid, 1,2,3-propanetricarboxylic acid, etc.
  • Examples of tetracarboxylic acids include ethylenetetracarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, cyclobutane-1,2,3,4-tetracarboxylic acid, benzene-1,2,4, 5-tetracarboxylic acid and the like.
  • the compounds other than those mentioned above include zinc chloride, lactic acid, oleic acid, stearic acid, glutamic acid, benzoic acid, glutamic acid hydrochloride, aniline hydrochloride, cetylpyridine bromide, urea, triethanolamine, glycerin, hydrazine, and rosin. mentioned.
  • the content of the flux is 20 parts by mass to 200 parts by mass, preferably 30 parts by mass to 180 parts by mass, more preferably 40 parts by mass to 160 parts by mass, based on 100 parts by mass of the liquid epoxy compound. .
  • the content of the flux is 20 parts by mass or more, the metallization of the metal particles can be sufficiently promoted in the cured product.
  • the content is 200 parts by mass or less, the flux does not hinder conduction in a cured product, and the conductivity tends to be good.
  • the conductive paste of the present invention may contain components other than the components described above within a range that does not impair the effects of the present invention.
  • the above-mentioned other components include components contained in known or commonly used compositions.
  • the other components include binder components other than the liquid epoxy compound, solvents, antifoaming agents, leveling agents, thickeners, adhesives, fillers, flame retardants, colorants, and the like. Only one kind of the other components may be used, or two or more kinds thereof may be used.
  • thermosetting compounds other than the liquid epoxy compound examples include thermosetting compounds other than the liquid epoxy compound.
  • thermosetting compound examples include epoxy compounds, acrylate compounds, phenol-based resins, urethane-based resins, melamine-based resins, and alkyd-based resins that are solid at room temperature.
  • solid at normal temperature shall mean the state which does not show fluidity
  • the conductive paste of the present invention may or may not contain the above other binder components.
  • the content thereof should be 50 parts by mass or less with respect to 100 parts by mass of the liquid epoxy compound, from the viewpoint of reducing the viscosity of the conductive paste and improving the handleability. is preferred, more preferably 30 parts by mass or less, and particularly preferably 10 parts by mass or less.
  • solvent examples include ketones such as methyl ethyl ketone, acetone and acetophenone; ethers such as methyl cellosolve, methyl carbitol, diethylene glycol dimethyl ether and tetrahydrofuran; and esters such as methyl cellosolve acetate, butyl acetate and methyl acetate. Solvents may be mentioned.
  • the content of the solvent in the conductive paste of the present invention is not particularly limited, but it is preferably 10% by mass or less, more preferably 5% by mass or less with respect to 100% by mass of the total amount of the conductive paste of the present invention. be.
  • the conductive paste of the present invention is BH type viscometer rotor No. 7 (rotational speed: 10 rpm) at 25° C. is preferably 300 dPa ⁇ s to 2500 dPa ⁇ s, more preferably 500 dPa ⁇ s to 2000 dPa ⁇ s. It exists in the tendency which is excellent in the filling property as the said viscosity is in the said range.
  • the conductive paste of the present invention can be used for filling holes such as vias and through holes in semiconductor packages.
  • it can be used for filling holes in multilayer substrates.
  • the thermosetting compound such as a liquid epoxy compound is cured by heat curing, and the high melting point metal particles (B1) and the low melting point metal particles ( B2) and the metal particles containing the low-melting-point metal particles (B3) are melted and metallized, and the metal particles and the contact portions of the conductive layer provided at the upper and lower ends of the through-hole are integrated. do.
  • the metal particles and the conductive layer are simply in contact with each other, higher conductivity can be obtained, and the reliability of bonding between the conductive paste and the conductive layer is remarkably improved.
  • the conductive paste has excellent adhesiveness to the insulating layer of the multilayer substrate, a multilayer substrate having high long-term reliability can be obtained.
  • the conductive paste of the present invention is not particularly limited, and can be produced by a known or commonly used method. For example, it can be produced by mixing the above components and stirring with a three-roll mill, planetary stirring device, planetary mixer, homomixer, paddle mixer, or the like.
  • the multilayer substrate of the present invention comprises a plurality of conductive layers and insulating layers interposed between the plurality of conductive layers, holes passing through the insulating layers are filled with a conductive paste cured product, and the conductive paste cured product is filled. It is preferable that the multilayer substrate is a multilayer substrate in which the conductive layers that are in contact with both surfaces of the insulating layer are electrically connected to each other.
  • the conductive layer is not particularly limited as long as it exhibits conductivity, but examples include gold, silver, copper, palladium, nickel, aluminum, or alloys containing one or more of these metals. Moreover, the conductive layer may be a single layer, or may be a laminate of the same or different types.
  • the thickness of the conductive layer is preferably 5 nm to 10 ⁇ m.
  • the thickness of the conductive layer is the total thickness of all layers.
  • the insulating layer is not particularly limited as long as it exhibits insulating properties, but examples thereof include plastic substrates (particularly plastic films) and glass plates.
  • the insulating layer may be a single layer or a laminate of the same or different types.
  • the thickness of the insulating layer is preferably 1 ⁇ m to 1000 ⁇ m.
  • the thickness of the insulating layer is the total thickness of all the layers.
  • the multilayer substrate preferably has a structure in which two or more layers of the conductive layers are formed on both sides of the insulating layer, and more preferably two to ten layers.
  • the high melting point metal particles (B1), the low melting point metal particles (B2), and the low melting point metal particles (B3) are melted and mutually It is preferably integrated with and alloyed.
  • the above-mentioned alloying is metallization in which adjacent metal particles are connected and integrated when used for filling holes in a multilayer substrate, and a conductive layer that contacts the metal particles at the upper and lower ends of the holes. It means to connect and integrate.
  • FIG. 1 is a schematic cross-sectional view showing an example of manufacturing a multilayer substrate using the conductive paste of the present invention.
  • reference numeral 1 indicates an insulating layer
  • reference numeral 2 indicates a conductive paste filled in through-holes of the insulating layer
  • reference numeral 3 indicates a conductive layer
  • reference numeral 2' indicates a cured product of the conductive paste 2.
  • reference numeral 3' denotes a patterned conductive layer. It should be noted that this figure shows an example in which the filler is in direct contact with the inner walls of the through-holes without through-hole plating being applied to the through-holes of the substrate.
  • conductive layers 3 are arranged on both upper and lower surfaces of the insulating layer 1, pressed and integrated, and heated under predetermined conditions. This heating cures the liquid epoxy compound and melts the metal particles, thereby promoting metallization in which adjacent metal particles are connected to each other and firmly bonding the end surfaces of the conductive layer and the metal particles. After curing, the conductive layer can be patterned as required, for example, as shown in (c).
  • heating conditions for the conductive paste conditions suitable for both curing of the liquid epoxy compound and metallization of the metal particles are selected. Heating may be performed within the temperature range of 150° C. to 180° C. for about 30 minutes to 120 minutes.
  • a multi-layer substrate in which three or more conductive layers and two or more insulating layers are alternately laminated can also be used. It can be manufactured according to the above.
  • Liquid epoxy compound trade name "jER871", high melting point metal particles (B1) manufactured by Mitsubishi Chemical Corporation 1: silver-coated copper powder (melting point 990 ° C., average particle size 3 ⁇ m), high melting point metal particles (B1) 2 manufactured by DOWA Electronics Co., Ltd. : Silver powder (melting point 961 ° C., average particle size 3 ⁇ m), high melting point metal particles (B1) manufactured by DOWA Electronics 3: copper powder (melting point 1083 ° C., average particle size 3 ⁇ m), low melting point metal manufactured by Fukuda Metal Particle Foil Powder Industry Co., Ltd.
  • Particles (B2): Sn—Bi alloy metal particles (Sn:Bi 42:58, melting point 138° C., average particle size 6 ⁇ m)
  • Low melting point metal particles (B3): Sn96.5-Ag3.0-Cu0.5 metal particles (Sn:Ag:Cu 96.5:3.0:0.5, melting point 217° C., average particle size 6 ⁇ m)
  • Curing agent phenolic curing agent, trade name “Tamanol 758”, manufactured by Arakawa Chemical Industries, Ltd. Flux: 8-ethyloctadecanedioic acid, manufactured by Okamura Oil Co., Ltd.
  • a ⁇ 100 ⁇ m 169-hole connection pattern is formed on an insulating layer (manufactured by Panasonic Corporation, product name “R-1551”) with a thickness of about 100 ⁇ m using a CO 2 laser, and the holes are filled with the above conductive paste by a printing method.
  • a substrate for evaluation was produced by pressing under the following pressure and temperature conditions using a vacuum press. Pressure: The surface pressure was increased from 0 kg/cm 2 to 10.2 kg/cm 2 over 17 minutes and maintained for 10 minutes. Next, the surface pressure was increased to 30.6 kg/cm 2 over 24 minutes, maintained for 46 minutes, and then decreased to 0 kg/cm 2 over 23 minutes. Temperature: The temperature was raised from 30°C to 130°C over 17 minutes and maintained for 10 minutes. Then, the temperature was raised to 180° C. over 24 minutes, maintained for 46 minutes, and then cooled to 30° C. over 23 minutes.
  • Examples 1 to 7 were excellent in conductivity and long-term reliability. Long-term reliability was insufficient in Comparative Example 1, which did not contain the low-melting-point metal particles (B3). In Comparative Example 3, in which the metal particle content did not reach 1700 parts by mass, the conductivity and long-term reliability were insufficient. Comparative Examples 2 and 4, in which the content of the metal particles exceeded 3300 parts by mass, lacked filling properties and reflow resistance, resulting in insufficient long-term reliability. Comparative Example 5 with less than 1 part by mass of the curing agent lacked long-term reliability, and Comparative Example 6 with more than 30 parts by mass of the curing agent had insufficient electrical conductivity. Comparative Example 7, in which the flux was less than 20 parts by mass, lacked long-term reliability, and Comparative Example 8, in which the flux was more than 200 parts by mass, had insufficient electrical conductivity.
  • Appendix 5 It consists of a plurality of conductive layers and an insulating layer interposed between the plurality of conductive layers, a hole passing through the insulating layer is filled with a cured conductive paste, and the insulating layer is formed through the cured conductive paste.
  • Appendix 6 In the hardened conductive paste, the high-melting-point metal particles (B1), the low-melting-point metal particles (B2), and the low-melting-point metal particles (B3) are melted, integrated with each other, and alloyed.
  • the multilayer substrate according to .

Abstract

The present invention provides a conductive paste which is capable of forming a cured product that achieves high conductivity and long-term reliability at the same time. The present invention provides a conductive paste which contains, per 100 parts by mass of a liquid epoxy compound, 1,700 parts by mass to 3,300 parts by mass of metal particles that include high melting point metal particles (B1) which contain silver and/or copper and have a melting point of 800°C or higher, low melting point metal particles (B2) which are formed of an alloy having a melting point of 130°C to 150°C, and low melting point metal particles (B3) which are formed of an alloy of two or more metals selected from the group consisting of tin, silver, copper, bismuth and indium, and have a melting point of 200°C to 240°C, 1 part by mass to 30 parts by mass of a curing agent, and 20 parts by mass to 200 parts by mass of a flux.

Description

導電性ペースト及び多層基板Conductive paste and multilayer substrate
　本発明は導電性ペースト及びこの導電性ペーストを使用した多層基板に関する。 The present invention relates to a conductive paste and a multilayer substrate using this conductive paste.
　基板のホール充填などに用いられる導電性ペーストとして、フラックス、硬化剤、熱硬化性樹脂、及び導電性フィラーを添加し、一定条件下で加熱することにより、樹脂が硬化するとともに、金属粒子が融解してメタライズ化する（即ち、金属粒子同士の金属間化合物を形成する）金属溶融ペーストが使用されている。 As a conductive paste used for filling holes in substrates, flux, curing agent, thermosetting resin, and conductive filler are added, and by heating under certain conditions, the resin hardens and the metal particles melt. Metal melting pastes have been used which metallize (ie, form intermetallics between metal particles) by heating.
　このような導電性ペーストにおいて長期の接続安定性を発揮させるため、導電性フィラーに高融点金属粒子と、低融点金属粒子とを組み合わせて使用する方法が知られていた（特許文献１、２）。 In order to exhibit long-term connection stability in such a conductive paste, a method of using a conductive filler in combination with high-melting metal particles and low-melting metal particles has been known (Patent Documents 1 and 2). .
　しかしながら、これらの方法で得られる導電性ペーストは今日の高機能化、小型化が求められている半導体装置として使用する場合、硬化物とした際の比抵抗が高く、導電性が十分ではなかった。 However, when the conductive pastes obtained by these methods are used in semiconductor devices, for which high functionality and miniaturization are required today, the specific resistance when cured is high and the conductivity is not sufficient. .
　また、導電性を改善するため、フッ素系界面活性剤を使用して導電性ペーストの濡れ性を改善し、接続性を向上させる発明も報告されている（特許文献３）。 In addition, in order to improve conductivity, an invention has been reported in which a fluorine-based surfactant is used to improve the wettability of a conductive paste and improve connectivity (Patent Document 3).
特開２００８－１０８６２９号公報JP 2008-108629 A 国際公開第２０１６／１３６２０４号WO2016/136204 特開２０２０－１５２７７８号公報Japanese Patent Application Laid-Open No. 2020-152778
　しかしながら、フッ素系界面活性剤を使用することで導電性ペーストの接着性を向上させることはできたが、硬化物とした際に比抵抗は低減されておらず、導電性は不十分であり、また長期の信頼性は評価されておらず、不明であった。 However, although it was possible to improve the adhesiveness of the conductive paste by using a fluorine-based surfactant, the specific resistance was not reduced when it was made into a cured product, and the conductivity was insufficient. In addition, long-term reliability was not evaluated and was unknown.
　したがって、硬化物とした際に高い導電性と、長期の信頼性とを高いレベルで両立する導電性ペーストは未だ得られていなかった。 Therefore, a conductive paste that achieves both high conductivity and long-term reliability at a high level when cured has not yet been obtained.
　本発明はこのような課題を解決するものであって、高い導電性と長期の信頼性とを両立する硬化物を形成可能な導電性ペーストを提供することを目的とする。 An object of the present invention is to solve such problems, and to provide a conductive paste capable of forming a cured product that achieves both high conductivity and long-term reliability.
　本発明者らは、上記目標を達成するために鋭意努力した結果、液状エポキシ樹脂１００質量部に対して、銀及び／又は銅を含有する融点８００℃以上の高融点金属粒子（Ｂ１）と、融点１３０℃～１５０℃の合金である低融点金属粒子（Ｂ２）と、錫、銀、銅、ビスマス、及びインジウムからなる群から選択された２種以上の合金である融点２００℃～２４０℃の低融点金属粒子（Ｂ３）とを含む金属粒子１７００質量部～３３００質量部、硬化剤１質量部～３０質量部、及びフラックス２０質量部～２００質量部を含有する導電性ペーストによれば、硬化物とした際に高い導電性と長期の信頼性とを有することを見出した。本発明はこれらの知見に基づいて完成されたものである。 The present inventors have made diligent efforts to achieve the above goals, and have found that, with respect to 100 parts by mass of the liquid epoxy resin, high melting point metal particles (B1) containing silver and/or copper and having a melting point of 800°C or higher, Low-melting-point metal particles (B2), which are alloys with a melting point of 130° C. to 150° C., and two or more alloys selected from the group consisting of tin, silver, copper, bismuth, and indium, with a melting point of 200° C.-240° C. According to the conductive paste containing 1700 parts by mass to 3300 parts by mass of metal particles containing low melting point metal particles (B3), 1 part by mass to 30 parts by mass of a curing agent, and 20 parts by mass to 200 parts by mass of flux, curing It has been found that the material has high conductivity and long-term reliability. The present invention has been completed based on these findings.
　すなわち、本発明は液状エポキシ化合物１００質量部に対して、銀及び／又は銅を含有する融点８００℃以上の高融点金属粒子（Ｂ１）と、融点１３０℃～１５０℃の合金である低融点金属粒子（Ｂ２）、と錫、銀、銅、ビスマス、及びインジウムからなる群から選択された２種以上の合金である融点２００℃～２４０℃の低融点金属粒子（Ｂ３）との３種以上の金属粒子とを含む金属粒子１７００質量部～３３００質量部、硬化剤１質量部～３０質量部、及びフラックスを２０質量部～２００質量部含有している導電性ペーストを提供する。 That is, the present invention provides high melting point metal particles (B1) containing silver and/or copper and having a melting point of 800° C. or higher and a low melting point metal alloy having a melting point of 130° C. to 150° C. per 100 parts by mass of a liquid epoxy compound. Particles (B2), and low-melting metal particles (B3) having a melting point of 200° C. to 240° C., which are two or more alloys selected from the group consisting of tin, silver, copper, bismuth, and indium. A conductive paste containing 1700 to 3300 parts by mass of metal particles, 1 to 30 parts by mass of a curing agent, and 20 to 200 parts by mass of flux.
　上記導電性ペーストは上記液状エポキシ化合物を使用することで金属粒子を多量配合することができ、その結果導電性を向上することができる。上記高融点金属粒子（Ｂ１）と、上記低融点金属粒子（Ｂ２）とを組み合わせて含有することにより、硬化物とした際の導電性に優れる。上記低融点金属粒子（Ｂ３）を含有することにより、硬化物とした際の長期信頼性を向上することができる。また、上記液状エポキシ化合物１００質量部に対して、上記高融点金属粒子（Ｂ１）と、上記低融点金属粒子（Ｂ２）と、上記低融点金属粒子（Ｂ３）とを含む金属粒子を１７００重量部～３３００重量部含有することで、上記導電性ペーストの硬化物における比抵抗を低減し、導電性を向上させつつ、クラックの発生を抑制するため長期の接続信頼性を向上させることができる。硬化剤１質量部～３０質量部含有することにより、硬化物とした際のクラックの発生を抑制し、長期信頼性を向上させることができる。フラックスを２０質量部～２００質量部を含有することにより、上記導電性ペーストの硬化物において比抵抗を低減し、導電性を向上することができる。 By using the liquid epoxy compound, the conductive paste can contain a large amount of metal particles, and as a result, the conductivity can be improved. By containing the high-melting-point metal particles (B1) and the low-melting-point metal particles (B2) in combination, the cured product has excellent conductivity. By containing the low-melting-point metal particles (B3), the long-term reliability of a cured product can be improved. Further, 1700 parts by weight of metal particles containing the high melting point metal particles (B1), the low melting point metal particles (B2), and the low melting point metal particles (B3) are added to 100 parts by mass of the liquid epoxy compound. By containing up to 3300 parts by weight, it is possible to reduce the specific resistance in the cured product of the conductive paste, improve the conductivity, and suppress the occurrence of cracks, thereby improving the long-term connection reliability. By containing 1 part by mass to 30 parts by mass of the curing agent, the occurrence of cracks in the cured product can be suppressed, and long-term reliability can be improved. By containing 20 parts by mass to 200 parts by mass of flux, the cured product of the conductive paste can have a reduced specific resistance and an improved electrical conductivity.
　本発明の導電性ペーストは、上記低融点金属粒子（Ｂ２）と、上記低融点金属粒子（Ｂ３）との質量比率が（Ｂ２）／（Ｂ３）＝０．９～４０であることが好ましい。上記低融点金属粒子（Ｂ２）と上記低融点金属粒子（Ｂ３）との質量比率が０．９以上であることにより、比抵抗が低減し、導電性に優れる傾向にある。また、上記低融点金属粒子（Ｂ２）と上記低融点金属粒子（Ｂ３）との質量比率が４０以下であることにより、クラックの発生を抑制して長期の接続信頼性を両立することが容易となる。 The conductive paste of the present invention preferably has a mass ratio of (B2)/(B3)=0.9 to 40 between the low melting point metal particles (B2) and the low melting point metal particles (B3). When the mass ratio of the low-melting-point metal particles (B2) and the low-melting-point metal particles (B3) is 0.9 or more, the specific resistance tends to be reduced and the conductivity tends to be excellent. Further, when the mass ratio of the low-melting-point metal particles (B2) and the low-melting-point metal particles (B3) is 40 or less, crack generation can be suppressed and long-term connection reliability can be easily achieved. Become.
　また、上記硬化剤は水酸基含有芳香族化合物であることが好ましい。 Also, the curing agent is preferably a hydroxyl group-containing aromatic compound.
　また、上記硬化剤はフェノール系硬化剤及び／又はナフトール系硬化剤であることが好ましい。 Also, the curing agent is preferably a phenol-based curing agent and/or a naphthol-based curing agent.
　また、本発明は複数の導電層と上記複数の導電層間に介在する絶縁層からなり、上記絶縁層を貫通するホールが本発明の導電性ペーストの硬化物により充填されており、上記導電性ペーストの硬化物を介して上記絶縁層の両面に接する導電層同士が相互に導通している多層基板を提供する。 Further, the present invention comprises a plurality of conductive layers and an insulating layer interposed between the plurality of conductive layers, holes penetrating the insulating layers are filled with a cured product of the conductive paste of the present invention, and the conductive paste A multilayer substrate in which conductive layers in contact with both surfaces of the insulating layer are electrically connected to each other through the cured product of (1).
　また、上記導電性ペースト硬化物において、上記高融点金属粒子（Ｂ１）と、低融点金属粒子（Ｂ２）と、低融点金属粒子（Ｂ３）とが融解して相互に一体化し、合金化していることが好ましい。 In the hardened conductive paste, the high-melting metal particles (B1), the low-melting metal particles (B2), and the low-melting metal particles (B3) are melted and integrated with each other to form an alloy. is preferred.
　本発明の導電性ペーストは、高い導電性と長期の信頼性とを両立する硬化物を形成可能である。 The conductive paste of the present invention can form a cured product that achieves both high conductivity and long-term reliability.
本発明の導電性ペーストを用いた多層基板の製造例を示す模式断面図である。It is a schematic cross section showing an example of manufacturing a multilayer substrate using the conductive paste of the present invention.
［導電性ペースト］
　本発明の導電性ペーストは、液状エポキシ化合物、金属粒子、硬化剤、及びフラックスを少なくとも含む。上記導電性ペーストは上記各成分以外のその他の成分を含んでいてもよい。 [Conductive paste]
The conductive paste of the present invention contains at least a liquid epoxy compound, metal particles, a curing agent and flux. The conductive paste may contain components other than the components described above.
（液状エポキシ化合物）
　上記液状エポキシ化合物は分子内（一分子中）に１以上のエポキシ基（オキシラニル基）を少なくとも有する化合物である。上記液状エポキシ化合物は、常温で液体のエポキシ化合物を意味する。なお、「常温で液体」とは、２５℃において無溶媒状態で流動性を示す状態であることを意味するものとする。本発明の導電性ペーストは流動性の高い上記液状エポキシ化合物を含有することにより、金属粒子を多量配合することができ、その結果導電性を向上することができる。上記液状エポキシ化合物は、一種のみを使用してもよいし、二種以上を使用してもよい。 (liquid epoxy compound)
The liquid epoxy compound is a compound having at least one epoxy group (oxiranyl group) in the molecule (in one molecule). The liquid epoxy compound means an epoxy compound that is liquid at room temperature. In addition, "liquid at room temperature" shall mean that it is in a state of exhibiting fluidity at 25°C in the absence of a solvent. Since the conductive paste of the present invention contains the liquid epoxy compound having high fluidity, a large amount of metal particles can be blended, and as a result, the conductivity can be improved. Only one kind of the liquid epoxy compound may be used, or two or more kinds thereof may be used.
　上記液状エポキシ化合物としては、特に限定されないが、例えば、ビスフェノール型エポキシ化合物、スピロ環型エポキシ化合物、ナフタレン型エポキシ化合物、ビフェニル型エポキシ化合物、テルペン型エポキシ化合物、ノボラック型エポキシ化合物、ダイマー酸変性エポキシ化合物、グリシジルアミン型エポキシ化合物、グリシジルエーテル型エポキシ化合物、ゴム変性エポキシ樹脂、又はキレート変性エポキシ樹脂などが挙げられる。中でも、抵抗値を低くでき、保存安定性に優れる観点からダイマー酸変性エポキシ化合物であることが好ましい。 Examples of the liquid epoxy compound include, but are not limited to, bisphenol-type epoxy compounds, spirocyclic-type epoxy compounds, naphthalene-type epoxy compounds, biphenyl-type epoxy compounds, terpene-type epoxy compounds, novolak-type epoxy compounds, and dimer acid-modified epoxy compounds. , glycidylamine-type epoxy compounds, glycidyl ether-type epoxy compounds, rubber-modified epoxy resins, chelate-modified epoxy resins, and the like. Among them, a dimer acid-modified epoxy compound is preferable from the viewpoint of low resistance and excellent storage stability.
　上記ビスフェノール型エポキシ化合物としては、例えば、ビスフェノールＡ型エポキシ化合物、ビスフェノールＦ型エポキシ化合物、ビスフェノールＳ型エポキシ化合物、又はテトラブロムビスフェノールＡ型エポキシ化合物などが挙げられる。 Examples of the bisphenol-type epoxy compounds include bisphenol A-type epoxy compounds, bisphenol F-type epoxy compounds, bisphenol S-type epoxy compounds, tetrabromobisphenol A-type epoxy compounds, and the like.
　上記ノボラック型エポキシ化合物としては、例えば、クレゾールノボラック型エポキシ化合物、フェノールノボラック型エポキシ化合物、α－ナフトールノボラック型エポキシ化合物、又は臭素化フェノールノボラック型エポキシ化合物などが挙げられる。 Examples of the novolak-type epoxy compounds include cresol novolak-type epoxy compounds, phenol novolak-type epoxy compounds, α-naphthol novolak-type epoxy compounds, and brominated phenol novolac-type epoxy compounds.
　上記ダイマー酸変性エポキシ化合物とは、ダイマー酸で変性したエポキシ化合物、すなわちダイマー酸構造中の少なくとも一つのカルボキシル基と多官能エポキシ化合物が反応したものである。ここでダイマー酸とは不飽和脂肪酸の二量体である。原料の不飽和脂肪酸は、特に限定されないが、例えば、オレイン酸やリノール酸などの炭素数１８の不飽和脂肪酸を主成分とする植物由来油脂が使用可能である。ダイマー酸の構造は、環状、非環状のいずれでもよい。 The dimer acid-modified epoxy compound is an epoxy compound modified with dimer acid, that is, a reaction of at least one carboxyl group in the dimer acid structure with a polyfunctional epoxy compound. A dimer acid is a dimer of an unsaturated fatty acid here. The unsaturated fatty acid used as the raw material is not particularly limited, but for example, plant-derived fats and oils mainly composed of unsaturated fatty acids having 18 carbon atoms such as oleic acid and linoleic acid can be used. The structure of the dimer acid may be either cyclic or non-cyclic.
　ダイマー酸変性を行うエポキシ化合物としては、特に限定されないが、例えば、上記エポキシ化合物として例示されたエポキシ化合物などが挙げられる。上記ダイマー酸変性エポキシ化合物に含まれるエポキシ化合物は、一種のみを使用してもよいし、二種以上を使用してもよい。例えば、ビスフェノール型、エーテルエステル型、ノボラックエポキシ型、エステル型、脂肪族型、芳香族型などの各種エポキシ化合物をダイマー酸で変性した公知のダイマー酸変性エポキシ化合物を用いることができる。 The epoxy compound that undergoes dimer acid modification is not particularly limited, but includes, for example, the epoxy compounds exemplified as the above epoxy compounds. Epoxy compounds contained in the dimer acid-modified epoxy compound may be used alone or in combination of two or more. For example, known dimer acid-modified epoxy compounds obtained by modifying various epoxy compounds such as bisphenol type, ether ester type, novolac epoxy type, ester type, aliphatic type, and aromatic type with dimer acid can be used.
　上記グリシジルアミン型エポキシ化合物としては、例えば、テトラグリシジルジアミノジフェニルメタン、Ｎ，Ｎ－ビス（２，３－エポキシプロピル）－４－（２，３－エポキシプロポキシ）アニリンなどのアミノフェノール型エポキシ化合物などが挙げられる。 Examples of the glycidylamine-type epoxy compounds include aminophenol-type epoxy compounds such as tetraglycidyldiaminodiphenylmethane and N,N-bis(2,3-epoxypropyl)-4-(2,3-epoxypropoxy)aniline. mentioned.
　上記グリシジルエーテル型エポキシ化合物としては、例えば、トリス（グリシジルオキシフェニル）メタン、テトラキス（グリシジルオキシフェニル）エタン、グリシジルアルキルエーテルなどが挙げられる。 Examples of the glycidyl ether-type epoxy compounds include tris(glycidyloxyphenyl)methane, tetrakis(glycidyloxyphenyl)ethane, and glycidyl alkyl ethers.
　上記ゴム変性エポキシ樹脂は、エポキシ樹脂中にゴム成分を含む。上記ゴム成分としては、例えば、ブタジエンゴム、アクリルゴム、シリコーンゴム、ブチルゴム、イソプレンゴム、スチレンゴム、クロロプレンゴム、ＮＢＲ、ＳＢＲ、ＩＲ、ＥＰＲなどが挙げられる。上記ゴム成分は、一種のみを使用してもよいし、二種以上を使用してもよい。 The rubber-modified epoxy resin contains a rubber component in the epoxy resin. Examples of the rubber component include butadiene rubber, acrylic rubber, silicone rubber, butyl rubber, isoprene rubber, styrene rubber, chloroprene rubber, NBR, SBR, IR, and EPR. Only one type of the rubber component may be used, or two or more types may be used.
（金属粒子）
　本発明の導電性ペーストは金属粒子として、銀及び／又は銅を含有する融点８００℃以上の高融点金属粒子（Ｂ１）と、融点１３０℃～１５０℃の合金である低融点金属粒子（Ｂ２）と、錫、銀、銅、ビスマス、及びインジウムからなる群から選択された２種以上の合金である融点２００℃～２４０℃の低融点金属粒子（Ｂ３）とを含む。 (metal particles)
In the conductive paste of the present invention, as metal particles, high-melting-point metal particles (B1) containing silver and/or copper and having a melting point of 800° C. or higher and low-melting-point metal particles (B2) being an alloy having a melting point of 130° C. to 150° C. and low-melting-point metal particles (B3) having a melting point of 200° C. to 240° C., which is an alloy of two or more selected from the group consisting of tin, silver, copper, bismuth, and indium.
＜高融点金属粒子（Ｂ１）＞
　上記高融点金属粒子（Ｂ１）は、銅（融点：１０８３℃）及び／又は銀（融点：９６１℃）を含む金属粒子である。本発明の導電性ペーストは上記高融点金属粒子（Ｂ１）と、上記低融点金属粒子（Ｂ２）とを組み合わせることで十分な導電性を発揮することが可能となる。また、上記高融点金属粒子（Ｂ１）は銅及び銀以外の金属を含有していてもよく、例えば、金（融点：１０６４℃）、ニッケル（融点：１４５５℃）、亜鉛（融点：４２０℃）、又はこれらのうちの一種以上を含む合金であって融点８００℃以上であるものなどが挙げられる。また、上記高融点金属粒子（Ｂ１）としては、一種のみを使用してもよいし、二種以上を使用してもよい。 <High Melting Point Metal Particles (B1)>
The high melting point metal particles (B1) are metal particles containing copper (melting point: 1083°C) and/or silver (melting point: 961°C). The conductive paste of the present invention can exhibit sufficient conductivity by combining the high melting point metal particles (B1) and the low melting point metal particles (B2). In addition, the high melting point metal particles (B1) may contain metals other than copper and silver, such as gold (melting point: 1064°C), nickel (melting point: 1455°C), zinc (melting point: 420°C) , or an alloy containing one or more of these and having a melting point of 800° C. or higher. As the high-melting-point metal particles (B1), only one type may be used, or two or more types may be used.
　また、上記高融点金属粒子（Ｂ１）は、金属被覆金属粒子であってもよく、例えば、銀被覆銅粒子、金被覆銅粒子、銀被覆ニッケル粒子、又は銀被覆合金粒子などが挙げられる。上記銀被覆合金粒子としては、例えば、銅を含む合金（例えば、銅とニッケルと亜鉛との合金からなる銅合金）が銀により被覆された銀被覆銅合金粒子などが挙げられる。 In addition, the high-melting-point metal particles (B1) may be metal-coated metal particles, such as silver-coated copper particles, gold-coated copper particles, silver-coated nickel particles, or silver-coated alloy particles. Examples of the silver-coated alloy particles include silver-coated copper alloy particles in which an alloy containing copper (for example, a copper alloy comprising an alloy of copper, nickel and zinc) is coated with silver.
　上記高融点金属粒子（Ｂ１）の融点は８００℃以上であり、好ましくは９００℃以上、より好ましくは１０００℃以上である。上記高融点金属粒子（Ｂ１）の融点が８００℃以上であることにより導電性の高い金属を金属粒子中に多量含有でき、硬化物とした際の導電性に優れる傾向にある。また、上記高融点金属粒子（Ｂ１）の融点は１３００℃以下であることが好ましく、より好ましくは１２００℃以下である。上記高融点金属粒子（Ｂ１）の融点が１３００℃以下であることにより、上記導電性ペーストを硬化物とした際に合金化しやすくなる傾向にある。 The melting point of the high melting point metal particles (B1) is 800°C or higher, preferably 900°C or higher, more preferably 1000°C or higher. When the melting point of the high-melting-point metal particles (B1) is 800° C. or higher, a large amount of highly conductive metal can be contained in the metal particles, and the cured product tends to have excellent conductivity. The melting point of the high-melting-point metal particles (B1) is preferably 1300° C. or lower, more preferably 1200° C. or lower. When the melting point of the high-melting-point metal particles (B1) is 1300° C. or lower, the conductive paste tends to be easily alloyed when cured.
　上記高融点金属粒子（Ｂ１）の含有量は上記液状エポキシ化合物１００質量部に対して、４００質量部～１８００質量部であることが好ましく、より好ましくは５００質量部～１５００質量部であり、さらに好ましくは６００質量部～１４００質量部であり、特に好ましくは７００質量部～１３００質量部である。上記液状エポキシ化合物１００質量部に対して、上記高融点金属粒子（Ｂ１）を４００質量部以上含有することにより、硬化物とした際に比抵抗を低下させ、十分な導電性を発揮させることが容易となる。また、上記高融点金属粒子（Ｂ１）の含有量が１８００質量部以下であることにより、穴埋め性に優れ、硬化物とした際のクラックの発生を抑制して長期の信頼性を向上させることができる。 The content of the high-melting-point metal particles (B1) is preferably 400 parts by mass to 1800 parts by mass, more preferably 500 parts by mass to 1500 parts by mass, based on 100 parts by mass of the liquid epoxy compound. It is preferably from 600 parts by mass to 1400 parts by mass, and particularly preferably from 700 parts by mass to 1300 parts by mass. By containing 400 parts by mass or more of the high-melting-point metal particles (B1) with respect to 100 parts by mass of the liquid epoxy compound, the specific resistance of the cured product can be lowered, and sufficient conductivity can be exhibited. easier. In addition, when the content of the high-melting-point metal particles (B1) is 1800 parts by mass or less, it is possible to improve the long-term reliability by suppressing the occurrence of cracks when the cured product is made into a cured product. can.
＜低融点金属粒子（Ｂ２）＞
　上記低融点金属粒子（Ｂ２）は、融点１３０℃～１５０℃の合金である金属粒子である。本発明の導電性ペーストは上記高融点金属粒子（Ｂ１）と、上記低融点金属粒子（Ｂ２）とを組み合わせることで十分な導電性を発揮することが可能となる。上記低融点金属粒子（Ｂ２）としては、一種のみを使用してもよいし、二種以上を使用してもよい。 <Low Melting Point Metal Particles (B2)>
The low-melting-point metal particles (B2) are metal particles that are an alloy with a melting point of 130.degree. C. to 150.degree. The conductive paste of the present invention can exhibit sufficient conductivity by combining the high melting point metal particles (B1) and the low melting point metal particles (B2). As the low-melting-point metal particles (B2), only one type may be used, or two or more types may be used.
　上記低融点金属粒子（Ｂ２）は錫（融点：２３２℃）、及びビスマス（融点：２７１℃）を含有する合金であることが好ましく、錫及びビスマスの他に融点が１３０℃～１５０℃になるようのであれば他の金属を含有していてもよい。また、上記低融点金属粒子（Ｂ２）における錫：ビスマスの質量比率は８０：２０～４０：６０であることが好ましい。錫：ビスマスが上記質量比率であることにより、上記融点金属粒子（Ｂ２）の融点を１３０℃～１５０℃の範囲内とすることが容易になる。 The low-melting-point metal particles (B2) are preferably an alloy containing tin (melting point: 232°C) and bismuth (melting point: 271°C). Other metals may be contained if appropriate. Further, the mass ratio of tin:bismuth in the low melting point metal particles (B2) is preferably 80:20 to 40:60. By setting the mass ratio of tin to bismuth as described above, it becomes easy to set the melting point of the melting point metal particles (B2) within the range of 130°C to 150°C.
　上記低融点金属粒子（Ｂ２）の融点は１３０℃～１５０℃であり、好ましくは１３５℃～１４５℃である。融点が上記範囲であることにより、上記導電性ペーストの硬化反応の際にメタライズ化を行うことが容易になる。 The melting point of the low melting point metal particles (B2) is 130°C to 150°C, preferably 135°C to 145°C. When the melting point is within the above range, it becomes easy to perform metallization during the curing reaction of the conductive paste.
　上記低融点金属粒子（Ｂ２）の含有量は上記液状エポキシ化合物１００質量部に対して、３００質量部～２４００質量部であることが好ましく、より好ましくは４００質量部～２３００質量部であり、さらに好ましくは５００質量部～２２００質量部であり、特に好ましくは６００質量部～２０００質量部である。上記低融点金属粒子（Ｂ２）の含有量が上記液状エポキシ化合物１００質量部に対して、３００質量部以上であることにより、硬化物とした際に十分な導電性を発揮することができる。また、上記低融点金属粒子（Ｂ２）の含有量が２４００質量部以下であることにより、穴埋め性に優れ、硬化物とした際のクラックの発生を抑制して長期の信頼性を向上させることができる。 The content of the low melting point metal particles (B2) is preferably 300 parts by mass to 2400 parts by mass, more preferably 400 parts by mass to 2300 parts by mass, based on 100 parts by mass of the liquid epoxy compound. It is preferably 500 to 2200 parts by mass, particularly preferably 600 to 2000 parts by mass. When the content of the low-melting-point metal particles (B2) is 300 parts by mass or more with respect to 100 parts by mass of the liquid epoxy compound, a cured product can exhibit sufficient conductivity. In addition, since the content of the low-melting-point metal particles (B2) is 2400 parts by mass or less, it is possible to improve the long-term reliability by suppressing the occurrence of cracks when the cured product is made into a cured product. can.
＜低融点金属粒子（Ｂ３）＞
　上記低融点金属粒子（Ｂ３）は、錫、銀、銅、ビスマス、及びインジウムからなる群から選択された２種以上の合金であり、融点が２００℃～２４０℃のものである。本発明の導電性ペーストは上記低融点金属粒子（Ｂ３）を含有することにより、導電性ペーストの長期信頼性を向上することができる。上記低融点金属粒子（Ｂ３）としては、一種のみを使用してもよいし、二種以上を使用してもよい。 <Low Melting Point Metal Particles (B3)>
The low-melting-point metal particles (B3) are an alloy of two or more selected from the group consisting of tin, silver, copper, bismuth, and indium, and have a melting point of 200°C to 240°C. The conductive paste of the present invention can improve the long-term reliability of the conductive paste by containing the low-melting-point metal particles (B3). As the low-melting-point metal particles (B3), only one kind may be used, or two or more kinds may be used.
　上記低融点金属粒子（Ｂ３）は錫を主成分とする合金であることが好ましい。また、融点が２００℃～２４０℃の範囲である限り、上述した金属以外の金属を含有していてもよい。上記合金の総量（１００質量％）のうち、錫の含有割合は８０質量％以上であることが好ましく、より好ましくは８５質量％以上であり、特に好ましくは９０質量％以上である。上記低融点金属粒子（Ｂ３）は錫を主成分として含有することで融点を２００℃～２４０℃とすることが容易となる。 The low-melting-point metal particles (B3) are preferably an alloy containing tin as a main component. Also, as long as the melting point is in the range of 200°C to 240°C, metals other than the metals mentioned above may be contained. The content of tin is preferably 80% by mass or more, more preferably 85% by mass or more, and particularly preferably 90% by mass or more in the total amount (100% by mass) of the alloy. The low-melting-point metal particles (B3) containing tin as a main component facilitates setting the melting point to 200°C to 240°C.
　上記低融点金属粒子（Ｂ３）の融点は２００℃～２４０℃であり、好ましくは２０５℃～２３５℃である。上記低融点金属粒子（Ｂ３）の融点が上記範囲であることにより、長期信頼性を向上することが容易になる。 The melting point of the low melting point metal particles (B3) is 200°C to 240°C, preferably 205°C to 235°C. When the melting point of the low-melting-point metal particles (B3) is within the above range, long-term reliability can be easily improved.
　上記低融点金属粒子（Ｂ３）の含有量は液状エポキシ化合物１００質量部に対して、４０質量部～７００質量部であることが好ましく、より好ましくは５０質量部～６００質量部であり、特に好ましくは６０質量部～５００質量部である。上記液状エポキシ化合物１００質量部に対して、上記低融点金属粒子（Ｂ３）の含有量が４０質量部以上であることにより、硬化物とした際に長期の接続信頼性を向上することができる。また、上記低融点金属粒子（Ｂ３）の含有量が７００質量部以下であることにより、適度な充填性を発揮することができる。 The content of the low melting point metal particles (B3) is preferably 40 to 700 parts by mass, more preferably 50 to 600 parts by mass, and particularly preferably 100 parts by mass of the liquid epoxy compound. is 60 parts by mass to 500 parts by mass. When the content of the low-melting-point metal particles (B3) is 40 parts by mass or more with respect to 100 parts by mass of the liquid epoxy compound, long-term connection reliability can be improved when cured. Moreover, when the content of the low-melting-point metal particles (B3) is 700 parts by mass or less, it is possible to exhibit appropriate filling properties.
　また、本発明の導電性ペーストは上記高融点金属粒子（Ｂ１）、上記低融点金属粒子（Ｂ２）、及び上記低融点金属粒子（Ｂ３）以外の金属粒子を含有していてもよい。 In addition, the conductive paste of the present invention may contain metal particles other than the high melting point metal particles (B1), the low melting point metal particles (B2), and the low melting point metal particles (B3).
　本発明の導電性ペーストに導電性と長期信頼性を発揮させる観点から、上記導電性ペーストに含まれる上記高融点金属粒子（Ｂ１）、上記低融点金属粒子（Ｂ２）、及び上記低融点金属粒子（Ｂ３）の合計量は金属粒子全量（１００質量％）のうち、９０質量％以上であることが好ましく、より好ましくは９５質量％以上であり、特に好ましくは９９質量％以上である。 From the viewpoint of allowing the conductive paste of the present invention to exhibit conductivity and long-term reliability, the high melting point metal particles (B1), the low melting point metal particles (B2), and the low melting point metal particles contained in the conductive paste The total amount of (B3) is preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably 99% by mass or more, based on the total amount (100% by mass) of the metal particles.
　上記金属粒子の形状としては、球状、フレーク状（鱗片状）、樹枝状、繊維状、不定形（多面体）などが挙げられる。上記高融点金属粒子（Ｂ１）、上記低融点金属粒子（Ｂ２）、及び上記低融点金属粒子（Ｂ３）のそれぞれにおいて、粒子形状は、異なっていてもよいし、同一であってもよい。中でも、導電性ペーストの穴埋め性、充填性、塗布安定性がより高く、導電性により優れる観点から、球状が好ましい。また、上記金属粒子の平均粒径（Ｄ５０）は、上記高融点金属粒子（Ｂ１）、上記低融点金属粒子（Ｂ２）、及び上記低融点金属粒子（Ｂ３）のそれぞれにおいて０．５μｍ～３０μｍであることが好ましく、より好ましくは１μｍ～１０μｍである。 The shape of the metal particles includes spherical, flake-like (scale-like), dendritic, fibrous, amorphous (polyhedral), and the like. The high-melting-point metal particles (B1), the low-melting-point metal particles (B2), and the low-melting-point metal particles (B3) may have different or identical particle shapes. Among them, a spherical shape is preferable from the viewpoint of higher filling properties, filling properties, and coating stability of the conductive paste and better conductivity. The average particle size (D50) of the metal particles is 0.5 μm to 30 μm for each of the high melting point metal particles (B1), the low melting point metal particles (B2), and the low melting point metal particles (B3). preferably 1 μm to 10 μm.
　本発明の導電性ペーストに使用する金属粒子の合計量が、上記液状エポキシ化合物１００質量部に対して、１７００質量部～３３００質量部であり、好ましくは１８００質量部～３２００質量部であり、より好ましくは１９００質量部～３０００質量部である。上記液状エポキシ化合物１００質量部に対して、上記金属粒子の含量が１７００質量部以上であることにより、硬化物とした際に比抵抗を低減して導電性を向上することができる。また、上記金属粒子の含量が３３００質量部以下であることにより、充填性を向上させ、長期の信頼性を向上させることができる。 The total amount of metal particles used in the conductive paste of the present invention is 1700 parts by mass to 3300 parts by mass, preferably 1800 parts by mass to 3200 parts by mass, relative to 100 parts by mass of the liquid epoxy compound. It is preferably 1900 parts by mass to 3000 parts by mass. When the content of the metal particles is 1700 parts by mass or more with respect to 100 parts by mass of the liquid epoxy compound, the specific resistance can be reduced and the conductivity can be improved when a cured product is obtained. In addition, since the content of the metal particles is 3300 parts by mass or less, it is possible to improve filling properties and improve long-term reliability.
　また、上記低融点金属粒子（Ｂ２）と上記低融点金属粒子（Ｂ３）との質量比率は（Ｂ２）／（Ｂ３）＝０．９～４０であることが好ましく、１．３～３５であることがより好ましい。上記導電性ペーストは上記低融点金属粒子（Ｂ２）と上記低融点金属粒子（Ｂ３）との質量比率が０．９以上であることにより、硬化物とした際に比抵抗が低減し、導電性に優れつつ、長期の信頼性を両立できる傾向にある。また、上記低融点金属粒子（Ｂ２）と上記低融点金属粒子（Ｂ３）との質量比率が４０以下であることにより、硬化物とした際に十分なリフロー耐性及びヒートサイクル耐性を有し、長期の信頼性に優れる傾向にある。 Further, the mass ratio of the low-melting metal particles (B2) and the low-melting metal particles (B3) is preferably (B2)/(B3)=0.9 to 40, and preferably 1.3 to 35. is more preferable. The conductive paste has a mass ratio of 0.9 or more between the low-melting-point metal particles (B2) and the low-melting-point metal particles (B3). It tends to be able to achieve both long-term reliability while being excellent in performance. In addition, since the mass ratio of the low-melting-point metal particles (B2) and the low-melting-point metal particles (B3) is 40 or less, the cured product has sufficient reflow resistance and heat cycle resistance, and can be used for a long period of time. tend to be more reliable.
（硬化剤）
　上記硬化剤は、本発明の導電性ペーストに含まれる液状エポキシ化合物を硬化させるものであることが好ましい。したがって、上記硬化剤は、エポキシ基と反応性を有する官能基を有することが好ましい。上記硬化剤は、一種のみを使用してもよいし、二種以上を使用してもよい。 (curing agent)
The curing agent preferably cures the liquid epoxy compound contained in the conductive paste of the present invention. Therefore, the curing agent preferably has a functional group reactive with an epoxy group. Only one kind of the curing agent may be used, or two or more kinds thereof may be used.
　上記硬化剤としては、例えば、イソシアネート系硬化剤、フェノール系硬化剤、ナフトール系硬化剤、イミダゾール系硬化剤、及びアミン系硬化剤などが挙げられる。また、上記硬化剤は、エポキシ化合物との反応性の観点から、水酸基含有芳香族化合物であることが好ましい。上記水酸基含有芳香族化合物としては、例えばフェノール系硬化剤、及びナフトール系硬化剤などが好ましい。 Examples of the curing agent include isocyanate-based curing agents, phenol-based curing agents, naphthol-based curing agents, imidazole-based curing agents, and amine-based curing agents. Moreover, the curing agent is preferably a hydroxyl group-containing aromatic compound from the viewpoint of reactivity with the epoxy compound. Preferable examples of the hydroxyl-containing aromatic compound include phenol-based curing agents and naphthol-based curing agents.
　上記フェノール系硬化剤としては、例えば、ノボラック構造を有するフェノール系硬化剤、含窒素フェノール系硬化剤、及びトリアジン骨格含有フェノール系硬化剤などが挙げられる。 Examples of the phenol-based curing agent include a phenol-based curing agent having a novolac structure, a nitrogen-containing phenol-based curing agent, and a triazine skeleton-containing phenol-based curing agent.
　上記ナフトール系硬化剤としては、例えば、ノボラック構造を有するナフトール系硬化剤、含窒素ナフトール系硬化剤、及びトリアジン骨格含有ナフトール系硬化剤などが挙げられる。 Examples of the naphthol-based curing agent include a naphthol-based curing agent having a novolak structure, a nitrogen-containing naphthol-based curing agent, and a triazine skeleton-containing naphthol-based curing agent.
　上記硬化剤の含有量は、上記液状エポキシ化合物１００質量部に対して、１質量部～３０質量部であり、好ましくは２質量部～２７質量部、より好ましくは３～２５質量部である。上記含有量が１質量部以上であると、上記導電性ペースト中の硬化性化合物の硬化が十分となり、長期信頼性に優れる傾向にある。上記含有量が３０質量部以下であると、硬化物とした際に硬化剤が導通を阻害せず、導電性が良好となる傾向にある。 The content of the curing agent is 1 to 30 parts by mass, preferably 2 to 27 parts by mass, more preferably 3 to 25 parts by mass with respect to 100 parts by mass of the liquid epoxy compound. When the content is 1 part by mass or more, the curing of the curable compound in the conductive paste is sufficient, and long-term reliability tends to be excellent. When the content is 30 parts by mass or less, the curing agent does not hinder conduction in a cured product, and conductivity tends to be good.
（フラックス）
　上記フラックスは、上記金属粒子のメタライズ化を促進させる役割を有する。上記フラックスとしては、例えば、多価カルボン酸化合物又はそれ以外の化合物が挙げられる。上記フラックスは、一種のみを使用してもよいし、二種以上を使用してもよい。 (flux)
The flux has a role of promoting metallization of the metal particles. Examples of the flux include polyvalent carboxylic acid compounds and other compounds. Only one kind of flux may be used, or two or more kinds thereof may be used.
　上記多価カルボン酸化合物としては、例えば、ジカルボン酸では、シュウ酸、グルタル酸、アジピン酸、コハク酸、セバシン酸、マロン酸、マレイン酸、フマル酸、フタル酸、ピメリン酸、スベリン酸、アゼライン酸、テレフタル酸、シトラコン酸、α－ケトグルタル酸、ジグリコール酸、チオジグリコール酸、ジチオジグリコール酸、４－シクロヘキセン－１，２－ジカルボン酸、ドデカン二酸、ジフェニルエーテル－４，４’－ジカルボン酸、ピリジン－２，６－ジカルボン酸、テトラヒドロカルボン酸、ヘキサヒドロカルボン酸、テトラヒドロフタル酸、ヘキサヒドロフタル酸、８－エチルオクタデカン二酸などが挙げられ、トリカルボン酸では、例えば、トリメリット酸、クエン酸、イソクエン酸、ブタン－１,２,４,－トリカルボン酸、シクロヘキサン－１，２，４－トリカルボン酸、ベンゼン－１,２,４－トリカルボン酸、１，２，３－プロパントリカルボン酸などが挙げられ、テトラカルボン酸では、例えば、エチレンテトラカルボン酸、１，２，３，４－ブタンテトラカルボン酸、シクロブタン－１,２,３,４－テトラカルボン酸、ベンゼン－１,２,４,５－テトラカルボン酸などが挙げられる。 Examples of the polyvalent carboxylic acid compounds include dicarboxylic acids such as oxalic acid, glutaric acid, adipic acid, succinic acid, sebacic acid, malonic acid, maleic acid, fumaric acid, phthalic acid, pimelic acid, suberic acid, and azelaic acid. , terephthalic acid, citraconic acid, α-ketoglutaric acid, diglycolic acid, thiodiglycolic acid, dithiodiglycolic acid, 4-cyclohexene-1,2-dicarboxylic acid, dodecanedioic acid, diphenyl ether-4,4'-dicarboxylic acid , pyridine-2,6-dicarboxylic acid, tetrahydrocarboxylic acid, hexahydrocarboxylic acid, tetrahydrophthalic acid, hexahydrophthalic acid, 8-ethyloctadecanedioic acid, etc. Tricarboxylic acids include, for example, trimellitic acid, citric acid, acid, isocitric acid, butane-1,2,4-tricarboxylic acid, cyclohexane-1,2,4-tricarboxylic acid, benzene-1,2,4-tricarboxylic acid, 1,2,3-propanetricarboxylic acid, etc. Examples of tetracarboxylic acids include ethylenetetracarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, cyclobutane-1,2,3,4-tetracarboxylic acid, benzene-1,2,4, 5-tetracarboxylic acid and the like.
　上記それ以外の化合物としては塩化亜鉛、乳酸、オレイン酸、ステアリン酸、グルタミン酸、安息香酸、グルタミン酸塩酸塩、アニリン塩酸塩、臭化セチルピリジン、尿素、トリエタノールアミン、グリセリン、ヒドラジン、及びロジンなどが挙げられる。 The compounds other than those mentioned above include zinc chloride, lactic acid, oleic acid, stearic acid, glutamic acid, benzoic acid, glutamic acid hydrochloride, aniline hydrochloride, cetylpyridine bromide, urea, triethanolamine, glycerin, hydrazine, and rosin. mentioned.
　上記フラックスの含有量は、上記液状エポキシ化合物１００質量部に対して、２０質量部～２００質量部であり、好ましくは３０質量部～１８０質量部、より好ましくは４０質量部～１６０質量部である。上記フラックスの含有量が２０質量部以上であると、硬化物とした際に上記金属粒子のメタライズ化を十分に促進することができる。上記含有量が２００質量部以下であると、硬化物とした際にフラックスが導通を妨げず、導電性が良好となる傾向にある。 The content of the flux is 20 parts by mass to 200 parts by mass, preferably 30 parts by mass to 180 parts by mass, more preferably 40 parts by mass to 160 parts by mass, based on 100 parts by mass of the liquid epoxy compound. . When the content of the flux is 20 parts by mass or more, the metallization of the metal particles can be sufficiently promoted in the cured product. When the content is 200 parts by mass or less, the flux does not hinder conduction in a cured product, and the conductivity tends to be good.
（その他の成分）
　本発明の導電性ペーストは、本発明の効果を損なわない範囲内において、上述の各成分以外のその他の成分を含有していてもよい。上記その他の成分としては、公知乃至慣用の組成物に含まれる成分が挙げられる。上記その他の成分としては、例えば、上記液状エポキシ化合物以外のその他のバインダー成分、溶剤、消泡剤、レベリング剤、増粘剤、粘着剤、充填剤、難燃剤、着色剤などが挙げられる。上記その他の成分は、一種のみを使用してもよいし、二種以上を使用してもよい。 (other ingredients)
The conductive paste of the present invention may contain components other than the components described above within a range that does not impair the effects of the present invention. The above-mentioned other components include components contained in known or commonly used compositions. Examples of the other components include binder components other than the liquid epoxy compound, solvents, antifoaming agents, leveling agents, thickeners, adhesives, fillers, flame retardants, colorants, and the like. Only one kind of the other components may be used, or two or more kinds thereof may be used.
　上記その他のバインダー成分としては、上記液状エポキシ化合物以外のその他の熱硬化性化合物が挙げられる。上記熱硬化性化合物としては、例えば常温で固体のエポキシ化合物、アクリレート化合物、フェノール系樹脂、ウレタン系樹脂、メラミン系樹脂、アルキド系樹脂などが挙げられる。なお、「常温で固体」とは、２５℃において無溶媒状態で流動性を示さない状態であることを意味するものとする。上記その他のバインダー成分は、一種のみを使用してもよいし、二種以上を使用してもよい。 Examples of the other binder components include thermosetting compounds other than the liquid epoxy compound. Examples of the thermosetting compound include epoxy compounds, acrylate compounds, phenol-based resins, urethane-based resins, melamine-based resins, and alkyd-based resins that are solid at room temperature. In addition, "solid at normal temperature" shall mean the state which does not show fluidity|liquidity in a solvent-free state at 25 degreeC. Only one kind of the other binder components may be used, or two or more kinds thereof may be used.
　本発明の導電性ペーストは、上記その他のバインダー成分を含有してもよいし、含有しなくてもよい。また、上記その他のバインダー成分を含有する場合、導電性ペーストの粘度を低下させ、取り扱い性を向上させる観点から、その含有量は上記液状エポキシ化合物１００質量部に対して５０質量部以下であることが好ましく、より好ましくは３０質量部以下であり、特に好ましくは１０質量部以下である。 The conductive paste of the present invention may or may not contain the above other binder components. In addition, when the other binder component is contained, the content thereof should be 50 parts by mass or less with respect to 100 parts by mass of the liquid epoxy compound, from the viewpoint of reducing the viscosity of the conductive paste and improving the handleability. is preferred, more preferably 30 parts by mass or less, and particularly preferably 10 parts by mass or less.
　上記溶剤としては、例えば、メチルエチルケトン、アセトン、アセトフェノンなどのケトン；メチルセロソルブ、メチルカルビトール、ジエチレングリコールジメチルエーテル、テトラヒドロフランなどのエーテル；メチルセロソルブアセテート、酢酸ブチル、酢酸メチルなどのエステルなどの公知乃至慣用の有機溶剤が挙げられる。 Examples of the solvent include ketones such as methyl ethyl ketone, acetone and acetophenone; ethers such as methyl cellosolve, methyl carbitol, diethylene glycol dimethyl ether and tetrahydrofuran; and esters such as methyl cellosolve acetate, butyl acetate and methyl acetate. Solvents may be mentioned.
　本発明の導電性ペーストにおける溶剤の含有割合は、特に限定されないが、本発明の導電性ペーストの総量１００質量％に対し、１０質量％以下であることが好ましく、より好ましくは５質量％以下である。 The content of the solvent in the conductive paste of the present invention is not particularly limited, but it is preferably 10% by mass or less, more preferably 5% by mass or less with respect to 100% by mass of the total amount of the conductive paste of the present invention. be.
　本発明の導電性ペーストはＢＨ型粘度計ローターＮｏ．７（回転速度：１０ｒｐｍ）により測定される２５℃における粘度が、３００ｄＰａ・ｓ～２５００ｄＰａ・ｓであることが好ましく、より好ましくは５００ｄＰａ・ｓ～２０００ｄＰａ・ｓである。上記粘度が上記範囲内であると、充填性に優れる傾向にある。 The conductive paste of the present invention is BH type viscometer rotor No. 7 (rotational speed: 10 rpm) at 25° C. is preferably 300 dPa·s to 2500 dPa·s, more preferably 500 dPa·s to 2000 dPa·s. It exists in the tendency which is excellent in the filling property as the said viscosity is in the said range.
　本発明の導電性ペーストは、半導体パッケージのビアやスルーホールなどのホール充填用とすることができる。特に、導電性及び長期信頼性に優れる観点から、多層基板のホール充填用とすることができる。 The conductive paste of the present invention can be used for filling holes such as vias and through holes in semiconductor packages. In particular, from the viewpoint of excellent conductivity and long-term reliability, it can be used for filling holes in multilayer substrates.
　本発明の導電性ペーストを多層基板のスルーホール充填に用いた場合、熱硬化により液状エポキシ化合物などの熱硬化性化合物が硬化するとともに、上記高融点金属粒子（Ｂ１）、上記低融点金属粒子（Ｂ２）、及び上記低融点金属粒子（Ｂ３）を含む金属粒子が融解してメタライズ化し、上記金属粒子と、スルーホールの上端部と下端部に設置された導電層の接触部と、が一体化する。この場合、上記金属粒子と上記導電層とが単に接触しているだけの場合と比較して高い導電性が得られ、かつ導電性ペーストと導電層との接合の信頼性が顕著に向上する。また、上記導電性ペーストは、多層基板の絶縁層との接着性にも優れるので、高い長期信頼性を有する多層基板が得られる。 When the conductive paste of the present invention is used to fill through holes in a multilayer substrate, the thermosetting compound such as a liquid epoxy compound is cured by heat curing, and the high melting point metal particles (B1) and the low melting point metal particles ( B2) and the metal particles containing the low-melting-point metal particles (B3) are melted and metallized, and the metal particles and the contact portions of the conductive layer provided at the upper and lower ends of the through-hole are integrated. do. In this case, compared to the case where the metal particles and the conductive layer are simply in contact with each other, higher conductivity can be obtained, and the reliability of bonding between the conductive paste and the conductive layer is remarkably improved. Moreover, since the conductive paste has excellent adhesiveness to the insulating layer of the multilayer substrate, a multilayer substrate having high long-term reliability can be obtained.
［導電性ペーストの製造方法］
　本発明の導電性ペーストは、特に限定されず、公知乃至慣用の方法により製造することができる。例えば、上記各成分を混合し、３本ロールミル、遊星式撹拌装置、プラネタリーミキサー、ホモミキサー、パドルミキサーなどで撹拌して製造することができる。 [Method for producing conductive paste]
The conductive paste of the present invention is not particularly limited, and can be produced by a known or commonly used method. For example, it can be produced by mixing the above components and stirring with a three-roll mill, planetary stirring device, planetary mixer, homomixer, paddle mixer, or the like.
［多層基板］
　本発明の多層基板は複数の導電層と上記複数の導電層間に介在する絶縁層からなり、上記絶縁層を貫通するホールが導電性ペースト硬化物により充填されており、上記導電性ペースト硬化物を介して上記絶縁層の両面に接する導電層同士が相互に導通している多層基板であることが好ましい。 [Multilayer board]
The multilayer substrate of the present invention comprises a plurality of conductive layers and insulating layers interposed between the plurality of conductive layers, holes passing through the insulating layers are filled with a conductive paste cured product, and the conductive paste cured product is filled. It is preferable that the multilayer substrate is a multilayer substrate in which the conductive layers that are in contact with both surfaces of the insulating layer are electrically connected to each other.
　上記導電層としては、導電性を発揮するものであれば特に限定されないが、例えば金、銀、銅、パラジウム、ニッケル、アルミニウム、若しくはこれらのうちの１以上の金属を含む合金などが挙げられる。また、上記導電層は単層であってもよいし、同種又は異種の積層体であってもよい。 The conductive layer is not particularly limited as long as it exhibits conductivity, but examples include gold, silver, copper, palladium, nickel, aluminum, or alloys containing one or more of these metals. Moreover, the conductive layer may be a single layer, or may be a laminate of the same or different types.
　上記導電層の厚さは、５ｎｍ～１０μｍが好ましい。なお、導電層が複層構成である場合、上記導電層の厚さは、全ての層厚さの合計である。 The thickness of the conductive layer is preferably 5 nm to 10 μm. When the conductive layer has a multilayer structure, the thickness of the conductive layer is the total thickness of all layers.
　上記絶縁層としては、絶縁性を発揮するものであれば特に限定されないが、例えば、プラスチック基材（特にプラスチックフィルム）、ガラス板などが挙げられる。上記絶縁層は、単層であってもよいし、同種又は異種の積層体であってもよい。 The insulating layer is not particularly limited as long as it exhibits insulating properties, but examples thereof include plastic substrates (particularly plastic films) and glass plates. The insulating layer may be a single layer or a laminate of the same or different types.
　上記絶縁層の厚さは、１μｍ～１０００μｍが好ましい。なお、絶縁層が複層構成である場合、上記絶縁層の厚さは、全ての層厚さの合計である。 The thickness of the insulating layer is preferably 1 μm to 1000 μm. In addition, when the insulating layer has a multilayer structure, the thickness of the insulating layer is the total thickness of all the layers.
　上記多層基板は上記絶縁層の両面に上記導電層が形成された構造が２層以上積層されたものであることが好ましく、より好ましくは２層～１０層積層されたものである。 The multilayer substrate preferably has a structure in which two or more layers of the conductive layers are formed on both sides of the insulating layer, and more preferably two to ten layers.
　また、上記多層基板に使用されている上記導電性ペースト硬化物において、上記高融点金属粒子（Ｂ１）、上記低融点金属粒子（Ｂ２）、及び上記低融点金属粒子（Ｂ３）が融解して相互に一体化し、合金化していることが好ましい。なお、上記合金化とは多層基板のホール充填に用いた場合に、隣接する金属粒子同士が繋がって一体化するメタライズ化するとともに、金属粒子と、ホールの上端部及び下端部で接触する導電層とも繋がって一体化することを言う。 Further, in the conductive paste cured product used in the multilayer substrate, the high melting point metal particles (B1), the low melting point metal particles (B2), and the low melting point metal particles (B3) are melted and mutually It is preferably integrated with and alloyed. The above-mentioned alloying is metallization in which adjacent metal particles are connected and integrated when used for filling holes in a multilayer substrate, and a conductive layer that contacts the metal particles at the upper and lower ends of the holes. It means to connect and integrate.
［多層基板の製造方法］
　図１は、本発明の導電性ペーストを用いた多層基板の製造例を示す模式断面図である。図１において、符号１は絶縁層を示し、符号２は絶縁層１のスルーホールに充填された導電性ペーストを示し、符号３は導電層を示し、符号２’は導電性ペースト２の硬化物を示し、符号３’はパターニングされた導電層を示す。なお、本図は、基板のスルーホールにスルーホールメッキが施されずに、充填物がスルーホール内壁に直接接触している例を示している。 [Manufacturing method of multilayer substrate]
FIG. 1 is a schematic cross-sectional view showing an example of manufacturing a multilayer substrate using the conductive paste of the present invention. In FIG. 1, reference numeral 1 indicates an insulating layer, reference numeral 2 indicates a conductive paste filled in through-holes of the insulating layer 1, reference numeral 3 indicates a conductive layer, and reference numeral 2' indicates a cured product of the conductive paste 2. and reference numeral 3' denotes a patterned conductive layer. It should be noted that this figure shows an example in which the filler is in direct contact with the inner walls of the through-holes without through-hole plating being applied to the through-holes of the substrate.
　本発明の多層基板を得るには、例えば、図１の（ａ）に示すように、予め加熱しておいた絶縁層１に、ドリルやレーザーによりスルーホールを形成したのち、スルーホール内に導電性ペースト２を充填して、（ｂ）に示すように、その絶縁層１の上下両面に導電層３を配してプレスして一体化し、所定の条件で加熱する。この加熱により液状エポキシ化合物を硬化させ、かつ金属粒子を融解させることで、隣接する金属粒子同士が繋がるメタライズ化が進行すると共に、導電層の端面と金属粒子とが強固に接合する。硬化後は、例えば（ｃ）に示すように、必要に応じて導電層にパターニングを行うことができる。 In order to obtain the multilayer substrate of the present invention, for example, as shown in FIG. Then, as shown in FIG. 1B, conductive layers 3 are arranged on both upper and lower surfaces of the insulating layer 1, pressed and integrated, and heated under predetermined conditions. This heating cures the liquid epoxy compound and melts the metal particles, thereby promoting metallization in which adjacent metal particles are connected to each other and firmly bonding the end surfaces of the conductive layer and the metal particles. After curing, the conductive layer can be patterned as required, for example, as shown in (c).
　導電性ペーストの加熱条件としては、液状エポキシ化合物の硬化と金属粒子のメタライズ化の双方に適した条件を選択するので、具体的な条件はペーストの組成により異なるが、おおよその目安としては、約１５０℃～１８０℃の温度範囲内で、約３０分～１２０分間程度加熱すればよい。なお、本図では、導電層が２層で絶縁層が１層の場合を示したが、３層以上の導電層と２層以上の絶縁層とが交互に積層された多層基板の場合も、上記に準じて製造することができる。 As the heating conditions for the conductive paste, conditions suitable for both curing of the liquid epoxy compound and metallization of the metal particles are selected. Heating may be performed within the temperature range of 150° C. to 180° C. for about 30 minutes to 120 minutes. Although the figure shows a case in which there are two conductive layers and one insulating layer, a multi-layer substrate in which three or more conductive layers and two or more insulating layers are alternately laminated can also be used. It can be manufactured according to the above.
　以下に、実施例に基づいて本発明の一実施形態をより詳細に説明する。 An embodiment of the present invention will be described in more detail below based on examples.
＜導電性ペーストの作製＞
　表１、表２に記載した各成分を配合して混合し、実施例及び比較例の各導電性ペーストを調製した（表中の数値は質量部を示す）。使用した各成分の詳細は以下の通りである。 <Preparation of conductive paste>
Each component described in Tables 1 and 2 was blended and mixed to prepare each conductive paste of Examples and Comparative Examples (values in the tables indicate parts by mass). Details of each component used are as follows.
　液状エポキシ化合物：商品名「ｊＥＲ８７１」、三菱ケミカル社製
　高融点金属粒子（Ｂ１）１：銀被覆銅粉（融点９９０℃、平均粒子径３μｍ）、ＤＯＷＡエレクトロニクス社製
　高融点金属粒子（Ｂ１）２：銀粉（融点９６１℃、平均粒子径３μｍ）、ＤＯＷＡエレクトロニクス社製
　高融点金属粒子（Ｂ１）３：銅粉（融点１０８３℃、平均粒子径３μｍ）、福田金属粒子箔粉工業社製
　低融点金属粒子（Ｂ２）：Ｓｎ－Ｂｉ合金金属粒子（Ｓｎ：Ｂｉ＝４２：５８、融点１３８℃、平均粒子径６μｍ）
　低融点金属粒子（Ｂ３）：Ｓｎ９６．５－Ａｇ３．０－Ｃｕ０．５金属粒子（Ｓｎ：Ａｇ：Ｃｕ＝９６．５：３．０：０．５、融点２１７℃、平均粒子径６μｍ）
　硬化剤：フェノール系硬化剤、商品名「タマノール７５８」、荒川化学工業社製
　フラックス：８－エチルオクタデカン二酸、岡村製油社製 Liquid epoxy compound: trade name "jER871", high melting point metal particles (B1) manufactured by Mitsubishi Chemical Corporation 1: silver-coated copper powder (melting point 990 ° C., average particle size 3 μm), high melting point metal particles (B1) 2 manufactured by DOWA Electronics Co., Ltd. : Silver powder (melting point 961 ° C., average particle size 3 μm), high melting point metal particles (B1) manufactured by DOWA Electronics 3: copper powder (melting point 1083 ° C., average particle size 3 μm), low melting point metal manufactured by Fukuda Metal Particle Foil Powder Industry Co., Ltd. Particles (B2): Sn—Bi alloy metal particles (Sn:Bi=42:58, melting point 138° C., average particle size 6 μm)
Low melting point metal particles (B3): Sn96.5-Ag3.0-Cu0.5 metal particles (Sn:Ag:Cu=96.5:3.0:0.5, melting point 217° C., average particle size 6 μm)
Curing agent: phenolic curing agent, trade name “Tamanol 758”, manufactured by Arakawa Chemical Industries, Ltd. Flux: 8-ethyloctadecanedioic acid, manufactured by Okamura Oil Co., Ltd.
＜評価用基板の作製＞
　厚さ約１００μｍの絶縁層（パナソニック社製、商品名「Ｒ－１５５１」）にＣＯ2レーザーを用いて、φ１００μｍの１６９孔連結パターンを形成し、印刷法により孔内に上記導電性ペーストを充填した後、真空プレス機を用いて次の圧力条件及び温度条件でプレスを行うことで評価用基板を作製した。
　圧力：０ｋｇ／ｃｍ2から１７分間かけて面圧１０．２ｋｇ／ｃｍ2まで昇圧し、そのまま１０分間保持した。次いで、２４分間かけて面圧３０．６ｋｇ／ｃｍ2まで昇圧し、そのまま４６分間保持した後、２３分間かけて０ｋｇ／ｃｍ2まで減圧した。
　温度：３０℃から１７分間かけて１３０℃まで昇温し、そのまま１０分間保持した。次いで、２４分間かけて１８０℃まで昇温し、そのまま４６分間保持した後、２３分間かけて３０℃まで冷却した。 <Preparation of substrate for evaluation>
A φ100 μm 169-hole connection pattern is formed on an insulating layer (manufactured by Panasonic Corporation, product name “R-1551”) with a thickness of about 100 μm using a CO 2 laser, and the holes are filled with the above conductive paste by a printing method. After that, a substrate for evaluation was produced by pressing under the following pressure and temperature conditions using a vacuum press.
Pressure: The surface pressure was increased from 0 kg/cm 2 to 10.2 kg/cm 2 over 17 minutes and maintained for 10 minutes. Next, the surface pressure was increased to 30.6 kg/cm 2 over 24 minutes, maintained for 46 minutes, and then decreased to 0 kg/cm 2 over 23 minutes.
Temperature: The temperature was raised from 30°C to 130°C over 17 minutes and maintained for 10 minutes. Then, the temperature was raised to 180° C. over 24 minutes, maintained for 46 minutes, and then cooled to 30° C. over 23 minutes.
［評価］
　上記導電性ペースト又は上記評価用基板を用いて各種物性値の評価を実施した。 [evaluation]
Various physical property values were evaluated using the conductive paste or the substrate for evaluation.
（１）比抵抗
　ガラスエポキシ基板上にメタル版を用いて実施例及び比較例で得られた上記導電性ペーストをライン印刷（長さ６０ｍｍ、幅１ｍｍ、厚さ約１００μｍ）し、１８０℃で６０分間加熱することにより本硬化させ、導電性パターンが形成された評価用基板を作製した。次いで、テスターを用いて導電性パターンの両端間の抵抗値を測定し、断面積（Ｓ、ｃｍ2）と長さ（Ｌ、ｃｍ）から下記式（１）により比抵抗を計算した。なお、ガラスエポキシ基板３枚に各５本のライン印刷を施して導電性パターンを合計１５本形成し、それらの比抵抗の平均値を求め、以下のように評価した。
　　　比抵抗＝（Ｓ／Ｌ）×Ｒ　　　　（１）
○：比抵抗が５×１０-5Ω・ｃｍ未満
×：比抵抗が５×１０-5Ω・ｃｍ以上 (1) Specific resistance The above conductive paste obtained in Examples and Comparative Examples was line-printed (length 60 mm, width 1 mm, thickness about 100 μm) using a metal plate on a glass epoxy substrate, and the resistance was 60 at 180 ° C. A substrate for evaluation on which a conductive pattern was formed was prepared by heating for 1 minute for final curing. Next, the resistance value between both ends of the conductive pattern was measured using a tester, and the specific resistance was calculated from the cross-sectional area (S, cm 2 ) and length (L, cm) by the following formula (1). Five lines were printed on each of three glass epoxy substrates to form a total of 15 conductive patterns.
Specific resistance = (S/L) x R (1)
○: Specific resistance is less than 5×10 −5 Ω·cm ×: Specific resistance is 5×10 −5 Ω·cm or more
（２）充填性
　上記評価用基板をＸ線透過装置（商品名「Ｙ．Ｃｈｅｅｔａｈ　μＨＤ」、エクスロン・インターナショナル社製）を用いて、以下の測定条件にてＶｉａ部分を観察し、充填性を評価した。
＜測定条件＞電圧：５０ｋＶ、電流：８０μＡ、電力：４Ｗ
○：印刷性良好
×：硬化時にペースト未充填、クラックが発生 (2) Fillability Using an X-ray transmission device (trade name “Y. Cheetah μHD”, manufactured by YXLON International), the Via portion of the evaluation substrate was observed under the following measurement conditions to evaluate the fillability. did.
<Measurement conditions> Voltage: 50 kV, current: 80 μA, power: 4 W
○: Good printability ×: Paste not filled and cracks occurred during curing
（３）初期Ｖｉａ抵抗値
　上記評価用基板の初期Ｖｉａ抵抗値の測定については、上記連結パターンの両端間の抵抗値を測定し、その抵抗値を各孔数で除算し、１孔当たりの抵抗値を求め、平均値を算出し、以下のように評価した。
○：４．０ｍΩ／Ｖｉａ未満
×：４．０ｍΩ／Ｖｉａ以上 (3) Initial Via resistance value For measurement of the initial Via resistance value of the evaluation substrate, the resistance value between both ends of the connection pattern is measured, the resistance value is divided by the number of holes, and the resistance per hole is Values were determined, average values were calculated, and evaluated as follows.
○: Less than 4.0 mΩ/Via ×: 4.0 mΩ/Via or more
（４）長期信頼性１（リフロー耐性）
　上記評価用基板を２６０℃、１０秒間のリフロー炉で処理することを５回繰り返した後のＶｉａ抵抗値を測定し、試験前の評価用基板からのＶｉａ抵抗値の変化率を評価した。なお、Ｖｉａ抵抗値の測定方法は、上記初期Ｖｉａ抵抗値の測定方法と同一である。また、以下の長期信頼性２～４に関しても、同様の評価を行った。
○：抵抗値変化率が±１０％以内の場合
×：抵抗値変化率が±１０％より大きい場合 (4) Long-term reliability 1 (reflow resistance)
The Via resistance value was measured after repeating five times that the evaluation board was treated in a reflow furnace at 260° C. for 10 seconds, and the change rate of the Via resistance value from the evaluation board before the test was evaluated. The method for measuring the Via resistance value is the same as the method for measuring the initial Via resistance value. In addition, similar evaluations were made for long-term reliability 2 to 4 below.
○: When the resistance value change rate is within ±10% ×: When the resistance value change rate is greater than ±10%
（５）長期信頼性２（ヒートサイクル耐性）
　上記評価用基板を－６０℃、３０分間と１２５℃、３０分間で処理するヒートサイクル試験１０００サイクル後、導電性ペーストの抵抗値を測定し、試験前の評価用基板からのＶｉａ抵抗値の変化率を算出し、上記のように評価した。 (5) Long-term reliability 2 (heat cycle resistance)
After 1000 cycles of the heat cycle test in which the evaluation substrate is treated at -60 ° C. for 30 minutes and 125 ° C. for 30 minutes, the resistance value of the conductive paste is measured, and the Via resistance value change from the evaluation substrate before the test. Percentages were calculated and evaluated as above.
（６）長期信頼性３（耐熱試験）
　上記評価用基板を１００℃、１０００時間静置後の導電性ペーストの抵抗値を測定し、試験前の評価用基板からのＶｉａ抵抗値の変化率を算出し、上記のように評価した。 (6) Long-term reliability 3 (heat resistance test)
The resistance value of the conductive paste was measured after the evaluation substrate was allowed to stand at 100° C. for 1000 hours, and the rate of change in Via resistance from the evaluation substrate before the test was calculated and evaluated as described above.
（７）長期信頼性４（耐湿試験）
　上記評価用基板を温度８５℃、湿度８５％の環境下で１０００時間静置後の導電性ペーストの抵抗値を測定し、試験前の評価用基板からのＶｉａ抵抗値の変化率の変化率を算出し、上記のように評価した。 (7) Long-term reliability 4 (humidity resistance test)
The resistance value of the conductive paste was measured after the evaluation substrate was allowed to stand for 1000 hours in an environment with a temperature of 85 ° C. and a humidity of 85%, and the rate of change in Via resistance value from the evaluation substrate before the test was calculated. was calculated and evaluated as above.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　実施例１～７では導電性及び長期の信頼性に優れていることが確認された。低融点金属粒子（Ｂ３）を含有していない比較例１では長期信頼性が不十分であった。金属粒子の含有量が１７００質量部に達していない比較例３では導電性、長期信頼性が不十分であった。金属粒子の含有量が３３００質量部超である比較例２、及び４では充填性とリフロー耐性に欠け長期信頼性が不十分であった。また、硬化剤が１質量部未満である比較例５では長期信頼性が欠ける結果となり、硬化剤が３０質量部超である比較例６では導電性が不十分であった。また、フラックスが２０質量部未満である比較例７では長期信頼性に欠ける結果であり、フラックスが２００質量部超である比較例８では導電性が不十分であった。 It was confirmed that Examples 1 to 7 were excellent in conductivity and long-term reliability. Long-term reliability was insufficient in Comparative Example 1, which did not contain the low-melting-point metal particles (B3). In Comparative Example 3, in which the metal particle content did not reach 1700 parts by mass, the conductivity and long-term reliability were insufficient. Comparative Examples 2 and 4, in which the content of the metal particles exceeded 3300 parts by mass, lacked filling properties and reflow resistance, resulting in insufficient long-term reliability. Comparative Example 5 with less than 1 part by mass of the curing agent lacked long-term reliability, and Comparative Example 6 with more than 30 parts by mass of the curing agent had insufficient electrical conductivity. Comparative Example 7, in which the flux was less than 20 parts by mass, lacked long-term reliability, and Comparative Example 8, in which the flux was more than 200 parts by mass, had insufficient electrical conductivity.
　以下に本発明のバリエーションを開示する。
［付記１］
　液状エポキシ化合物１００質量部に対して、
　銀及び／又は銅を含有する融点８００℃以上の高融点金属粒子（Ｂ１）と、融点１３０℃～１５０℃の合金である低融点金属粒子（Ｂ２）と、錫、銀、銅、ビスマス、及びインジウムからなる群から選択された２種以上の合金である融点２００℃～２４０℃の低融点金属粒子（Ｂ３）とを含む金属粒子１７００質量部～３３００質量部、
　硬化剤１質量部～３０質量部、
　及びフラックス２０質量部～２００質量部を含有している導電性ペースト。
［付記２］
　前記低融点金属粒子（Ｂ２）と、前記低融点金属粒子（Ｂ３）との質量比率が（Ｂ２）／（Ｂ３）＝０．９～４０である付記１に記載の導電性ペースト。
［付記３］
　前記硬化剤が水酸基含有芳香族化合物である付記１又は２に記載の導電性ペースト。
［付記４］
　前記硬化剤がフェノール系硬化剤及び／又はナフトール系硬化剤である付記１～３のいずれか１項に記載の導電性ペースト。
［付記５］
　複数の導電層と前記複数の導電層間に介在する絶縁層からなり、前記絶縁層を貫通するホールが導電性ペースト硬化物により充填されており、前記導電性ペースト硬化物を介して前記絶縁層の両面に接する導電層同士が相互に導通している多層基板であり、前記導電性ペースト硬化物が付記１～４のいずれか１項に記載の導電性ペーストの硬化物である多層基板。
［付記６］
　前記導電性ペースト硬化物において、前記高融点金属粒子（Ｂ１）、前記低融点金属粒子（Ｂ２）、及び前記低融点金属粒子（Ｂ３）が融解して相互に一体化し、合金化している付記５に記載の多層基板。 Variations of the invention are disclosed below.
[Appendix 1]
For 100 parts by mass of the liquid epoxy compound,
High melting point metal particles (B1) containing silver and/or copper and having a melting point of 800° C. or higher, low melting point metal particles (B2) being an alloy having a melting point of 130° C. to 150° C., tin, silver, copper, bismuth, and 1700 parts by mass to 3300 parts by mass of metal particles containing low melting point metal particles (B3) having a melting point of 200 ° C. to 240 ° C. which are two or more alloys selected from the group consisting of indium,
Curing agent 1 part by mass to 30 parts by mass,
and a conductive paste containing 20 parts by mass to 200 parts by mass of flux.
[Appendix 2]
The conductive paste according to Appendix 1, wherein the mass ratio of the low melting point metal particles (B2) and the low melting point metal particles (B3) is (B2)/(B3)=0.9 to 40.
[Appendix 3]
3. The conductive paste according to appendix 1 or 2, wherein the curing agent is a hydroxyl group-containing aromatic compound.
[Appendix 4]
4. The conductive paste according to any one of Appendices 1 to 3, wherein the curing agent is a phenol-based curing agent and/or a naphthol-based curing agent.
[Appendix 5]
It consists of a plurality of conductive layers and an insulating layer interposed between the plurality of conductive layers, a hole passing through the insulating layer is filled with a cured conductive paste, and the insulating layer is formed through the cured conductive paste. A multilayer substrate in which the conductive layers on both sides are electrically connected to each other, and the cured conductive paste is a cured conductive paste according to any one of Appendices 1 to 4.
[Appendix 6]
In the hardened conductive paste, the high-melting-point metal particles (B1), the low-melting-point metal particles (B2), and the low-melting-point metal particles (B3) are melted, integrated with each other, and alloyed. The multilayer substrate according to .
　１　絶縁層
　２　導電性ペースト
　２’　導電性ペーストの硬化物
　３　導電層
　３’　パターニングされた導電層 REFERENCE SIGNS LIST 1 insulating layer 2 conductive paste 2' hardened conductive paste 3 conductive layer 3' patterned conductive layer

Claims (6)

  1. 　液状エポキシ化合物１００質量部に対して、
    　銀及び／又は銅を含有する融点８００℃以上の高融点金属粒子（Ｂ１）と、融点１３０℃～１５０℃の合金である低融点金属粒子（Ｂ２）と、錫、銀、銅、ビスマス、及びインジウムからなる群から選択された２種以上の合金である融点２００℃～２４０℃の低融点金属粒子（Ｂ３）とを含む金属粒子１７００質量部～３３００質量部、
    　硬化剤１質量部～３０質量部、
    　及びフラックス２０質量部～２００質量部を含有している導電性ペースト。     For 100 parts by mass of the liquid epoxy compound,
    High melting point metal particles (B1) containing silver and/or copper and having a melting point of 800° C. or higher, low melting point metal particles (B2) being an alloy having a melting point of 130° C. to 150° C., tin, silver, copper, bismuth, and 1700 parts by mass to 3300 parts by mass of metal particles containing low melting point metal particles (B3) having a melting point of 200 ° C. to 240 ° C. which are two or more alloys selected from the group consisting of indium,
    Curing agent 1 part by mass to 30 parts by mass,
    and a conductive paste containing 20 parts by mass to 200 parts by mass of flux.
  2. 　前記低融点金属粒子（Ｂ２）と、前記低融点金属粒子（Ｂ３）との質量比率が（Ｂ２）／（Ｂ３）＝０．９～４０である請求項１に記載の導電性ペースト。 The conductive paste according to Claim 1, wherein the mass ratio of the low melting point metal particles (B2) and the low melting point metal particles (B3) is (B2)/(B3) = 0.9 to 40.
  3. 　前記硬化剤が水酸基含有芳香族化合物である請求項１又は２に記載の導電性ペースト。 The conductive paste according to claim 1 or 2, wherein the curing agent is a hydroxyl group-containing aromatic compound.
  4. 　前記硬化剤がフェノール系硬化剤及び／又はナフトール系硬化剤である請求項１又は２に記載の導電性ペースト。 The conductive paste according to claim 1 or 2, wherein the curing agent is a phenol-based curing agent and/or a naphthol-based curing agent.
  5. 　複数の導電層と前記複数の導電層間に介在する絶縁層からなり、前記絶縁層を貫通するホールが導電性ペースト硬化物により充填されており、前記導電性ペースト硬化物を介して前記絶縁層の両面に接する導電層同士が相互に導通している多層基板であり、前記導電性ペースト硬化物が請求項１又は２に記載の導電性ペーストの硬化物である多層基板。 It consists of a plurality of conductive layers and an insulating layer interposed between the plurality of conductive layers, a hole passing through the insulating layer is filled with a cured conductive paste, and the insulating layer is formed through the cured conductive paste. 3. A multilayer substrate in which the conductive layers on both sides are electrically connected to each other, and the cured conductive paste is the cured conductive paste according to claim 1 or 2.
  6. 　前記導電性ペースト硬化物において、前記高融点金属粒子（Ｂ１）、前記低融点金属粒子（Ｂ２）、及び前記低融点金属粒子（Ｂ３）が融解して相互に一体化し、合金化している請求項５に記載の多層基板。 In the hardened conductive paste, the high-melting metal particles (B1), the low-melting metal particles (B2), and the low-melting metal particles (B3) are melted, integrated with each other, and alloyed. 5. The multilayer substrate according to 5.
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008034242A (en) * 2006-07-28 2008-02-14 Fujikura Kasei Co Ltd Conductive paste
JP2012523091A (en) * 2009-04-02 2012-09-27 オーメット サーキッツ インク Conductive composition comprising mixed alloy filler
JP2015511888A (en) * 2011-12-13 2015-04-23 ダウ コーニング コーポレーションＤｏｗ Ｃｏｒｎｉｎｇ Ｃｏｒｐｏｒａｔｉｏｎ Composition and conductor formed therefrom
WO2016136204A1 (en) * 2015-02-27 2016-09-01 タツタ電線株式会社 Conductive paste and multilayer substrate using same
WO2022034696A1 (en) * 2020-08-11 2022-02-17 タツタ電線株式会社 Electroconductive composition

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008034242A (en) * 2006-07-28 2008-02-14 Fujikura Kasei Co Ltd Conductive paste
JP2012523091A (en) * 2009-04-02 2012-09-27 オーメット サーキッツ インク Conductive composition comprising mixed alloy filler
JP2015511888A (en) * 2011-12-13 2015-04-23 ダウ コーニング コーポレーションＤｏｗ Ｃｏｒｎｉｎｇ Ｃｏｒｐｏｒａｔｉｏｎ Composition and conductor formed therefrom
WO2016136204A1 (en) * 2015-02-27 2016-09-01 タツタ電線株式会社 Conductive paste and multilayer substrate using same
WO2022034696A1 (en) * 2020-08-11 2022-02-17 タツタ電線株式会社 Electroconductive composition

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