WO2020145170A1 - Conductive adhesive agent composition - Google Patents

Conductive adhesive agent composition Download PDF

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Publication number
WO2020145170A1
WO2020145170A1 PCT/JP2019/051028 JP2019051028W WO2020145170A1 WO 2020145170 A1 WO2020145170 A1 WO 2020145170A1 JP 2019051028 W JP2019051028 W JP 2019051028W WO 2020145170 A1 WO2020145170 A1 WO 2020145170A1
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WO
WIPO (PCT)
Prior art keywords
conductive adhesive
particles
adhesive composition
average particle
particle diameter
Prior art date
Application number
PCT/JP2019/051028
Other languages
French (fr)
Japanese (ja)
Inventor
真太郎 阿部
近藤　剛史
Original Assignee
田中貴金属工業株式会社
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Application filed by 田中貴金属工業株式会社 filed Critical 田中貴金属工業株式会社
Publication of WO2020145170A1 publication Critical patent/WO2020145170A1/en

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/02—Non-macromolecular additives
    • C09J11/04—Non-macromolecular additives inorganic
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/08—Macromolecular additives
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J201/00—Adhesives based on unspecified macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J9/00—Adhesives characterised by their physical nature or the effects produced, e.g. glue sticks
    • C09J9/02—Electrically-conducting adhesives
    • 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
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/50—Assembly of semiconductor devices using processes or apparatus not provided for in a single one of the subgroups H01L21/06 - H01L21/326, e.g. sealing of a cap to a base of a container
    • H01L21/52—Mounting semiconductor bodies in containers

Definitions

  • the present invention relates to a conductive adhesive composition.
  • a conductive adhesive composition is used as a die bond material for bonding and joining a semiconductor element to a support member such as a lead frame in electronic parts.
  • metal powder such as silver powder or copper powder is generally used because it has high electrical conductivity, and an adhesive containing these or a paste-like adhesive that is bonded by sintering.
  • Patent Document 1 flakes having an average particle diameter of 2 to 20 ⁇ m, a tap density (TD) of 2.0 to 7.0 g/cm 3 , and a carbon-containing compound content of 0.5 mass% or less. It has been reported that a conductive paste is characterized by containing a granular silver powder, silver nanoparticles having an average particle diameter of 10 to 500 nm, and a thermosetting resin.
  • Patent Document 2 silver powder, silver fine particles, fatty acid silver, and amine are included, and the silver powder has an average particle diameter of 0.3 ⁇ m to 100 ⁇ m, and the silver fine particles have an average primary particle diameter of 50.
  • the crystallite size is 20 to 50 nm, the ratio of the average particle size to the crystallite size is 1 to 7.5, and further, a thermally conductive composition containing silver resinate is reported. ing.
  • a cured product (hereinafter, also referred to as an adhesive layer) of a conductive adhesive composition in which metal particles of nanometer order are added to metal particles of micrometer order as described above forms a dense sintered structure.
  • voids are still present in the cured product.
  • a cured product of a conductive adhesive composition obtained by adding nanometer-order metal particles to micrometer-order metal particles has low stress relaxation performance due to its dense crystal structure.
  • the stress relaxation performance is further deteriorated due to the formation of large voids in the vicinity of the bonding interface as the metal moves.
  • the material to be adhered is likely to be peeled off due to the stress generated by the difference in the coefficient of linear thermal expansion between the materials to be adhered.
  • the content of the metal component in the conductive adhesive composition is increased to increase the packing density.
  • a conductive adhesive composition containing a total of 80% or more of metal particles of micrometer order and nanometer order with respect to the total amount of the conductive adhesive composition are disclosed in the examples.
  • such a cured product of a conductive adhesive composition having a high metal content generally has low stress relaxation performance, and the above-mentioned peeling is particularly likely to occur.
  • the present invention has been invented in view of the above problems, and an object thereof is excellent in thermal conductivity, and further, conductive adhesion capable of sufficiently suppressing peeling of the adherend material even when subjected to repeated temperature changes. To provide an agent composition.
  • a conductive adhesive composition containing particles of a thermoplastic resin having a temperature of 130 to 250° C. realizes an adhesive having excellent thermal conductivity and in which peeling of a material to be adhered does not easily occur even when subjected to repeated temperature changes. They have found that they can do so and have completed the present invention.
  • the conductive adhesive composition of the present invention comprises a conductive filler (A) containing metal particles (a1) having an average particle diameter of 0.5 to 10 ⁇ m and silver particles (a2) having an average particle diameter of 10 to 200 nm,
  • the thermoplastic resin particles (B) having an average particle diameter of 2 to 14 ⁇ m are contained, and the melting point of the thermoplastic resin is 130 to 250° C.
  • the main component of the metal particles (a1) is silver.
  • the conductive adhesive composition according to one aspect of the present invention contains 35 to 85% by mass of metal particles (a1) and 5 to 50% by mass of silver particles (a2) based on the total amount of the conductive adhesive composition. It is contained in the range of %.
  • the content ratio of the metal particles (a1) and the silver particles (a2) is in the range of 95:5 to 40:60 by mass ratio.
  • the conductive adhesive composition according to one aspect of the present invention contains the thermoplastic resin particles (B) in the range of 0.1 to 10 mass% with respect to the total amount of the conductive adhesive composition.
  • the conductive adhesive cured product of the present invention is a cured product of any one of the conductive adhesive compositions described above.
  • the electronic device of the present invention uses the conductive adhesive composition according to any one of the above for bonding components.
  • the conductive adhesive composition of the present invention contains a conductive filler (A) containing metal particles (a1) having an average particle diameter of 0.5 to 10 ⁇ m and silver particles (a2) having an average particle diameter of 10 to 200 nm. By doing so, the thermal conductivity is improved. Further, the inclusion of the thermoplastic resin particles (B) having an average particle diameter of 2 to 14 ⁇ m and a melting point of 130 to 250° C. causes repeated temperature changes due to the inclusion of nanometer-order silver particles. In this case, the increase in the possibility of peeling of the adherend material is suppressed. From this, the conductive adhesive of the present invention has excellent thermal conductivity, and further, peeling of the adherend material when subjected to repeated temperature changes is sufficiently suppressed.
  • the average particle size of the metal particles (a1) and the particles of the thermoplastic resin (B) is 50% of the particle size distribution measured using a laser diffraction/scattering particle size analyzer (D50). ).
  • the average particle diameter can be measured using, for example, a laser diffraction/scattering particle size analyzer MT-3000 manufactured by Nikkiso Co., Ltd.
  • the average particle size of the silver particles (a2) is the 50% average particle size (D50) of the particle size distribution measured using the dynamic light scattering method.
  • the average particle diameter can be measured using, for example, a Nanotrac particle distribution measuring device manufactured by Nikkiso Co., Ltd.
  • the conductive filler (A) in the embodiment of the present invention contains metal particles (a1) having an average particle diameter of 0.5 to 10 ⁇ m and silver particles (a2) having an average particle diameter of 10 to 200 nm.
  • the average particle diameter of the metal particles (a1) in the embodiment of the present invention is 0.5 ⁇ m or more, preferably 0.6 ⁇ m or more, more preferably 0.7 ⁇ m or more, and further preferably 0.8 ⁇ m or more. is there.
  • the average particle size of the metal particles (a1) in the embodiment of the present invention is 10 ⁇ m or less, preferably 8 ⁇ m or less, more preferably 7 ⁇ m or less, and further preferably 6 ⁇ m or less.
  • the average particle diameter of the metal particles (a1) in the embodiment of the present invention is 0.5 to 10 ⁇ m, preferably 0.6 to 8 ⁇ m, more preferably 0.7 to 7 ⁇ m, and further preferably 0.1. It is 8 to 6 ⁇ m.
  • the average particle size of the metal particles (a1) is less than 0.5 ⁇ m, the contraction of the conductive adhesive composition after curing is not suppressed, so that the adhesion with the adherend material is deteriorated.
  • the average particle diameter of the metal particles (a1) exceeds 10 ⁇ m, the sintering of the metal particles (a1) is difficult to proceed and the adhesion with the adherend material is reduced.
  • the metal particles (a1) in the embodiment of the present invention are not particularly limited as long as they are components that contribute to the conductivity of the conductive adhesive. Of these, metals and carbon nanotubes are preferable.
  • metal powder that is treated as a general conductor can be used.
  • simple substances such as silver, copper, gold, nickel, aluminum, chromium, platinum, palladium, tungsten, molybdenum, alloys composed of two or more kinds of these metals, coated products of these metals, oxides of these metals, or these metals.
  • compounds having good conductivity are listed.
  • a metal containing silver as a main component is more preferable because it is difficult to oxidize and has high thermal conductivity.
  • the "main component” refers to the component with the highest content among the components constituting the metal particles.
  • the tap density of the metal particles (a1) is not particularly limited, but is preferably 4 g/cm 3 or more, and more preferably 5 g/cm 3 or more in order to secure the adhesive strength to the adherend material. More preferably, it is 5.5 g/cm 3 or more. Further, in order to prevent the metal particles (a1) from settling and becoming unstable when the conductive adhesive composition is stored for a long time, it is preferably 8 g/cm 3 or less, and 7.5 g/cm 3 or less. It is more preferable that the amount is 7 g/cm 3 or less.
  • the tap density is measured and calculated by a metal powder-tap density measuring method of JIS standard Z2512:2012, for example.
  • the specific surface area of the metal particles (a1) is not particularly limited, but is preferably 0.1 m 2 /g or more, more preferably 0.2 m 2 /g or more, further preferably 0.3 m 2 /g. That is all.
  • the specific surface area of the metal particles (a1) is preferably 3 m 2 /g or less, more preferably 2 m 2 /g or less, and further preferably 1 m 2 /g or less.
  • the specific surface area of the metal particles (a1) is preferably 0.1 ⁇ 3m 2 / g, more preferably 0.2 ⁇ 2m 2 / g, more preferably 0.3 ⁇ 1 m 2 / It is g.
  • the specific surface area of the metal particles (a1) is 0.1 m 2 /g or more, the surface area of the metal particles (a1) in contact with the adherend material can be secured. Moreover, when the specific surface area of the metal particles (a1) is 3 m 2 /g or less, the amount of the solvent added to the conductive composition can be reduced.
  • the shape of the metal particles (a1) is not particularly limited, and examples thereof include spherical shape, flake shape, plate shape, foil shape, and dendritic shape. In general, flakes or spheres are selected.
  • the metal particles (a1) not only particles made of a single metal but also surface-coated metal particles made of two or more kinds of metals, or a mixture thereof can be used.
  • the average particle diameter of the silver particles (a2) in the embodiment of the present invention is 10 nm or more, preferably 20 nm or more, more preferably 30 nm or more, and further preferably 40 nm or more.
  • the average particle size of the silver particles (a2) in the embodiment of the present invention is 200 nm or less, preferably 180 nm or less, more preferably 170 nm or less, and further preferably 160 nm or less.
  • the average particle diameter of the silver particles (a2) in the embodiment of the present invention is 10 to 200 nm, preferably 20 to 180 nm, more preferably 30 to 170 nm, further preferably 40 to 160 nm.
  • the average particle size of the silver particles (a2) is less than 10 nm, it is difficult to remove the organic material coating the silver particles, and it is difficult to proceed with sintering.
  • the average particle diameter of the silver particles (a2) exceeds 200 nm, the specific surface area becomes small and it is difficult to sinter the silver particles.
  • the tap density of the silver particles (a2) is not particularly limited, but is preferably 4 g/cm 3 or more, and preferably 5 g/cm 3 or more in order to increase the contact points of the silver particles and facilitate sintering. More preferably, it is more preferably 5.5 g/cm 3 or more. Further, in order to prevent the silver particles (a2) from settling and becoming unstable when the conductive adhesive composition is stored for a long time, it is preferably 8 g/cm 3 or less, and 7.5 g/cm 3 or less. It is more preferable that the amount is 7 g/cm 3 or less.
  • the tap density is measured and calculated by a metal powder-tap density measuring method of JIS standard Z2512:2012, for example.
  • the shape of the silver particles (a2) is not particularly limited, and examples thereof include a spherical shape, a cubic shape, and a rod shape.
  • As the silver particles (a2) in addition to pure silver particles, metal particles whose surface is coated with silver, or a mixture thereof can be used.
  • the surface of the silver particles (a2) may be coated with a coating agent.
  • the coating agent and the coating method used are not particularly limited, and examples thereof include a coating agent containing a functional group of amine or carboxylic acid. Above all, it is preferable to use a coating agent containing a carboxylic acid functional group, because the heat dissipation of the conductive adhesive composition can be further improved.
  • the coating agent is preferably one that is easily removed when heated, and the functional group is preferably a carboxylic acid.
  • the coating agent containing a functional group of carboxylic acid is not particularly limited, and examples thereof include monocarboxylic acid, polycarboxylic acid and oxycarboxylic acid.
  • the carboxylic acid contained in the coating agent may be a mixture of two or more kinds.
  • the coating agent is preferably a higher fatty acid which is a saturated fatty acid having 12 to 24 carbon atoms or an unsaturated fatty acid.
  • Examples of the method of coating the surface of the silver particles (a2) with a coating agent include a method of stirring and kneading the both in a mixer, a method of impregnating the silver particles (a2) with a solution of a carboxylic acid and volatilizing the solvent.
  • the well-known method of is mentioned.
  • the content of the metal particles (a1) is the whole of the conductive adhesive composition in order to improve conductivity and thermal conductivity and to secure coatability.
  • the amount is preferably 35% by mass or more, more preferably 40% by mass or more, and further preferably 45% by mass or more.
  • the content of the metal particles (a1) is preferably 85% by mass or less, more preferably 75% by mass or less, and 65% by mass or less with respect to the total amount of the conductive adhesive composition. Is more preferable.
  • the content of the metal particles (a1) is preferably 35 to 85 mass% with respect to the total amount of the conductive adhesive composition, and 40 to 75 mass. %, more preferably 45 to 65% by mass.
  • the content of the silver particles (a2) is preferably 5% by mass or more, more preferably 10% by mass or more, and 15% by mass or more with respect to the total amount of the conductive adhesive composition. It is more preferable that there is.
  • the content of the silver particles (a2) is preferably 50% by mass or less, more preferably 40% by mass or less, and 35% by mass or less with respect to the total amount of the conductive adhesive composition. It is more preferable that there is.
  • the content of the silver particles (a2) is preferably 5 to 50% by mass, more preferably 10 to 40% by mass, and 15 to 35% based on the total amount of the conductive adhesive composition. More preferably, it is mass %.
  • the content ratio of the metal particles (a1) and the silver particles (a2) is 95:5 to 40 by mass ratio. :60 is preferable, 90:10 to 50:50 is more preferable, and 85:15 to 60:40 is further preferable.
  • conductive filler in the conductive adhesive composition of the embodiment of the present invention, other conductive fillers can be used in combination as long as the effect of the present invention is not impaired.
  • the conductive filler is not particularly limited as long as it has conductivity, and examples thereof include carbon nanotubes.
  • the conductive adhesive composition according to the embodiment of the present invention further contains particles (B) of a thermoplastic resin having an average particle diameter of 2 to 14 ⁇ m and a melting point of 130 to 250° C.
  • a cured product of a conductive adhesive composition containing silver particles of the nanometer order as in the present invention (hereinafter, also simply referred to as "conductive adhesive cured product”) has a dense structure, so that stress relaxation is achieved. Poor performance. Further, the metal is grown by being subjected to repeated temperature changes, which further reduces the stress relaxation performance. Therefore, in the adhesion using the conductive adhesive composition containing silver particles in the order of nanometers, the material to be adhered is likely to be peeled off due to the stress caused by the difference in the coefficient of linear thermal expansion between the materials to be adhered.
  • thermoplastic resin particles (B) when the thermoplastic resin particles (B) are cured by heating, the thermoplastic resin particles (B) melt and Fill the voids in the cured adhesive. It is considered that this prevents the movement of the metal in the cured product of the conductive adhesive and prevents the peeling of the adherend material due to the stress due to the growth of the metal as described above.
  • thermoplastic resin filled in the voids in the conductive adhesive cured product is capable of relieving stress by elastic deformation, improving the stress relaxation performance of the conductive adhesive cured product, Further, the thermoplastic resin fills the voids existing at the adhesive interface between the conductive adhesive cured product and the adherend material, which improves the adhesive strength, which also contributes to the suppression of peeling due to repeated temperature changes. it is conceivable that.
  • thermoplastic resin particles (B) have an effect of suppressing the occurrence or development of cracks in the cured conductive adhesive.
  • the molten thermoplastic resin is dispersed inside the cured product of the conductive adhesive composition of the embodiment of the present invention, this resin has the effect of dispersing the stress at the crack tip, causing a crack by hitting the crack.
  • the effect of stopping the progress the effect of deforming and consuming the energy of the crack progress, the generation and progress of the crack can be suppressed.
  • the particles (B) of the thermoplastic resin be melted during the curing of the conductive adhesive composition to fill the voids in the cured conductive adhesive. ..
  • the appropriate heating temperature for curing the conductive adhesive composition varies depending on various conditions such as the type of the conductive filler (A), but is usually 130 to 250°C. Therefore, in the embodiment of the present invention, the melting point of the thermoplastic resin particles (B) is 250° C. so that the thermosetting resin particles (B) are sufficiently melted when the conductive adhesive composition is cured. Below. Further, the melting point of the particles (B) of the thermoplastic resin is preferably 230°C or lower, more preferably 200°C or lower.
  • the melting point of the thermoplastic resin particles (B) is 130° C. or higher so that the thermoplastic resin particles (B) are not melted before the sintering of the conductive filler (A). To do. Further, the melting point of the thermoplastic resin particles (B) is preferably 140° C. or higher, more preferably 150° C. or higher, and even more preferably 160° C. or higher.
  • the average particle diameter of the thermoplastic resin particles (B) is also important.
  • the average particle diameter of the thermoplastic resin particles (B) is large, the number of particles in the same amount is small, and the effect of dispersing stress becomes poor.
  • the average particle diameter of the thermoplastic resin particles (B) is large, there are places where the ratio of resin particles existing in the thickness direction of the adhesive layer is very high. Can be a vulnerability.
  • the adhesive layer cannot be made thin, and the heat generated from the adherend such as a semiconductor element cannot be efficiently dissipated.
  • the average particle diameter of the particles (B) of the plastic resin is too large. From the above, the average particle diameter of the thermoplastic resin particles (B) is 14 ⁇ m or less. The average particle diameter of the thermoplastic resin particles (B) is preferably 13 ⁇ m or less. On the other hand, if the average particle size is too small, the stress relaxation ability and the crack growth suppressing effect become poor. From the above, the average particle diameter of the thermoplastic resin particles (B) is 2 ⁇ m or more. The average particle size of the thermoplastic resin particles (B) is preferably 3 ⁇ m or more.
  • the thermoplastic resin particles (B) in the embodiment of the present invention may be known resin particles satisfying the above-mentioned conditions of melting point and average particle diameter.
  • known polyamides such as nylon 11, nylon 12, nylon 6, AS resin, ABS resin, AES resin, vinyl acetate resin, polystyrene, polyethylene, polypropylene, polyvinyl chloride, acrylic resin, methacrylic resin, polyvinyl alcohol resin, polyvinyl Ether, polyacetal, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyvinyl butyral, polyvinyl formal, polysulfone, polyether sulfone, polyimide, phenoxy resin polyetherimide, ethyl cellulose, cellulose acetate, various fluororesins, polyolefin elastomers, silicone resins, etc. Examples thereof include particles, and a mixture or copolymer of these may be used.
  • the shape of the particles (B) of the thermoplastic resin in the embodiment of the present invention is not particularly limited, and examples thereof include substantially spherical shape, cubic shape, cylindrical shape, prismatic shape, conical shape, pyramidal shape, flake shape, foil shape and dendritic shape. Etc., but a substantially spherical shape or a cubic shape is preferable.
  • the content of the thermoplastic resin particles (B) is set to be high in order to prevent peeling of the adherend material when subjected to repeated temperature changes at a high level. It is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, further preferably 1% by mass or more, and 2% by mass or more based on the total amount of the adhesive composition. Is particularly preferable.
  • the content of the thermoplastic resin particles (B) is set to be conductive. It is preferably 10% by mass or less, more preferably 7% by mass or less, and further preferably 5% by mass or less based on the total amount of the adhesive composition.
  • the conductive filler (A) and the thermoplastic resin particles (B) may be dispersed in the binder resin.
  • the binder resin is not particularly limited, but for example, an epoxy resin, a phenol resin, a urethane resin, an acrylic resin, a silicone resin, a polyimide resin, or the like can be used, and these may be used alone or in combination of two or more kinds. .. From the viewpoint of workability, the binder resin in the embodiment of the present invention is preferably a thermosetting resin, and particularly preferably an epoxy resin.
  • the content of the binder resin is preferably 10% by mass or less, more preferably 8% by mass or less, and further preferably 6% by mass or less with respect to the total amount of the conductive adhesive composition. ..
  • the content of the binder resin is 10% by mass or less, a network due to necking of the conductive filler is easily formed, and stable conductivity and thermal conductivity are obtained.
  • the binder resin is contained, it is preferably used in an amount of 0.5% by mass or more.
  • the conductive adhesive composition of the embodiment of the present invention may contain, for example, a curing agent in addition to the above components.
  • a curing agent examples include amine-based curing agents such as tertiary amine, alkylurea, and imidazole, and phenol-based curing agents.
  • the content of the curing agent is preferably 2% by mass or less based on the total amount of the conductive adhesive composition. By doing so, the uncured curing agent is less likely to remain, and the adhesion with the adherend material becomes good.
  • a curing accelerator may be added to the conductive adhesive composition according to the embodiment of the present invention.
  • the curing accelerator include 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-methyl-4-methylimidazole, 1-cyano-2-ethyl.
  • Examples thereof include imidazoles such as -4-methylimidazole, tertiary amines, triphenylphosphines, urea compounds, phenols, alcohols, carboxylic acids and the like.
  • the curing accelerator may be used alone or in combination of two or more.
  • the compounding amount of the curing accelerator is not limited and may be appropriately determined, but when used, it is generally 0.5% by mass with respect to the total amount of the conductive adhesive composition of the embodiment of the present invention. It is as follows.
  • the conductive adhesive composition of the embodiment of the present invention may further contain a solvent in order to make the conductive adhesive composition into a paste form.
  • a solvent having a property of not dissolving the thermoplastic resin particles (B) is used in order to maintain the shape of the thermoplastic resin particles (B) in the paste.
  • Others are not particularly limited, but those having a boiling point of 350° C. or less are preferable, and those having a boiling point of 300° C. or less are more preferable because the solvent is easily volatilized during curing of the conductive adhesive composition. Specific examples thereof include acetate, ether and hydrocarbon, and more specifically, dibutyl carbitol, butyl carbitol acetate and the like are preferably used.
  • the content of the solvent is usually 15% by mass or less based on the conductive adhesive composition, and preferably 10% by mass or less from the viewpoint of workability.
  • an antioxidant in addition to the above components, an antioxidant, an ultraviolet absorber, a tackifier, a viscosity modifier, a dispersant, a coupling agent, a toughening agent, An elastomer or the like can be appropriately blended within a range that does not impair the effects of the embodiment of the present invention.
  • the conductive adhesive composition according to the embodiment of the present invention can be obtained by mixing and stirring the above components (A) and (B) and other components in any order.
  • a method such as a two-roll, a three-roll, a sand mill, a roll mill, a ball mill, a colloid mill, a jet mill, a bead mill, a kneader, a homogenizer, and a propellerless mixer can be adopted.
  • the electrically conductive adhesive cured product of the embodiment of the present invention is obtained by heat treating the electrically conductive adhesive composition to cure it.
  • the temperature of heating when curing the conductive adhesive composition of the embodiment of the present invention is not particularly limited, but between the conductive fillers (A), and between the adherend material and the conductive filler (A).
  • the temperature is preferably 150° C. or higher, more preferably 180° C. or higher, and further preferably 200° C. or higher. ..
  • the temperature is 300° C. or lower in order to prevent the conductive fillers (A) from excessively adhering to each other and causing necking between the conductive fillers (A) to strongly bond with each other and become too hard.
  • the temperature is preferably 275° C. or lower, more preferably 250° C. or lower.
  • the heating time is not particularly limited as long as the conductive filler (A) is sufficiently sintered, but is usually 0.5 to 3 hours.
  • the heating may be performed in air or in an inert gas such as N 2 .
  • the coating agent on the surface of the conductive filler (A) is easily removed, so that it is easy to sinter, but since the conductive filler (A) is easily oxidized, the obtained conductive adhesive is cured. There is a risk that the electrical conductivity and thermal conductivity of the object will be impaired.
  • an adherend that easily oxidizes for example, a Cu substrate
  • the adherend is oxidized and the bonding is hindered, and other peripheral members that are easily oxidized are oxidized. There is also a risk of deterioration.
  • the conductive adhesive cured product is thin.
  • the thickness of the cured product of the conductive adhesive is preferably 50 ⁇ m or less, more preferably 40 ⁇ m or less, still more preferably 30 ⁇ m or less.
  • the cured conductive adhesive be thicker, because it takes on the internal stress generated by the difference in thermal expansion of adherends such as substrates in the thickness direction of the adhesive layer.
  • the thickness of the cured product of the conductive adhesive is preferably 5 ⁇ m or more, more preferably 10 ⁇ m or more, still more preferably 20 ⁇ m or more.
  • the thermal conductivity of the conductive adhesive cured product of the embodiment of the present invention is preferably 20 W/m ⁇ K or more, and is 35 W/m ⁇ K or more in order to secure the heat dissipation of the adherend material. More preferably, it is more preferably 50 W/m ⁇ K or more.
  • the thermal conductivity of the conductive adhesive cured product can be calculated by the method described later in the Example section.
  • a method for evaluating that peeling of the material to be bonded is less likely to occur even when subjected to repeated temperature changes examples include various methods, for example, a method of performing a thermal cycle test by the method described below in the Example section, and measuring the ratio of the peeled area after the test by the method described below in the Example section. ..
  • the ratio of the peeled area measured by the method is preferably 15% or less, more preferably 10% or less, and further preferably 5% or less.
  • the conductive adhesive composition according to the embodiment of the present invention can be used for bonding components in electronic devices.
  • Epoxy resin (1) "EPICLON 830-S” (trade name), manufactured by Dainippon Ink and Chemicals, Inc., liquid at room temperature, epoxy equivalent: 169 g/eq
  • Epoxy resin (2) "ERISYS GE-21” (trade name), manufactured by CVC, liquid at room temperature, epoxy equivalent: 125 g/eq -Curing agent: Phenolic curing agent (MEH8000H, manufactured by Meiwa Kasei Co., Ltd.) ⁇ Promoting curing agent: 2-phenyl-4,5-dihydroxymethylimidazole (2PHZ, manufactured by Shikoku Kasei) ⁇ Solvent (1): Dibutyl carbitol (Tokyo Chemical Industry Co., Ltd.) ⁇ Solvent (2): Butyl carbitol acetate (manufactured by Tokyo Chemical Industry Co., Ltd.)
  • the obtained conductive adhesive composition was applied to a 10 mm ⁇ 10 mm silver-plated copper lead frame, and a 5 mm ⁇ 5 mm silver-sputtering silicon chip was placed on the coated surface, and then at 60° C. at 250° C. in a nitrogen atmosphere. After heating for minutes, a silver-plated copper lead frame and a silver-sputtered silicon chip were joined by a conductive adhesive cured product (hereinafter, also simply referred to as “metal joined body”). The physical properties of the obtained metal bonded body were evaluated by the methods described below.
  • the thermal conductivity of the obtained metal bonded body is shown in Tables 1 to 3.
  • Peeling test 2 was performed in the same manner as peeling test 1 except that the number of cooling and heating cycles was 3000. The results are shown in Tables 1 to 3. In addition, "-" in the column of the peeling test 2 in Tables 1 to 3 means that the peeling test 2 was not performed.
  • the metal bonded bodies obtained with the conductive adhesive compositions of Examples were compared with the metal bonded bodies obtained with the conductive adhesive compositions of Comparative Examples after the thermal cycling test.
  • the peeled area was small.
  • the thermal conductivity was also a good value.
  • the conductive adhesive composition according to the embodiment of the present invention can achieve an adhesive having excellent thermal conductivity and in which peeling of the adherend material is less likely to occur even when subjected to repeated temperature changes. Was done.

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Abstract

The present invention relates to a conductive adhesive agent composition which comprises (A) a conductive filler comprising (a1) metal particles having an average particle diameter of 0.5 to 10 μm and (a2) silver particles having an average particle diameter of 10 to 200 nm and (B) particles of a thermoplastic resin which have an average particle diameter of 2 to 14 μm, wherein the melting point of the thermoplastic resin is 130 to 250°C.

Description

導電性接着剤組成物Conductive adhesive composition
　本発明は、導電性接着剤組成物に関する。 The present invention relates to a conductive adhesive composition.
　電子部品において、半導体素子をリードフレーム等の支持部材に接着・接合するためのダイボンド材として、導電性接着剤組成物が用いられている。導電性接着剤組成物には、高い電気伝導性を有することから銀粉や銅粉等の金属粉が一般的に用いられており、これらを含む接着剤や焼結により接着するペースト状の接着剤に関する報告が多くなされている。 A conductive adhesive composition is used as a die bond material for bonding and joining a semiconductor element to a support member such as a lead frame in electronic parts. In the conductive adhesive composition, metal powder such as silver powder or copper powder is generally used because it has high electrical conductivity, and an adhesive containing these or a paste-like adhesive that is bonded by sintering. There have been many reports regarding.
　ここで、近年小型化・高機能化された電子部品、例えば、パワーデバイス又は発光ダイオード（ＬＥＤ）に対する需要が急速に拡大しており、電子部品の小型化が進行するに伴い、半導体素子の発熱量は増大傾向にある。ところが、半導体素子は、高温環境に長時間さらされると、本来の機能を発揮することができなくなり、また、寿命が低下することになる。そのため、ダイボンド材には半導体素子から発生した熱を支持部材に効率よく逃がすために、高い熱伝導率が求められており、その要求水準は上昇を続けている。 Here, in recent years, there has been a rapid expansion in demand for electronic components that have been made smaller and have higher functionality, such as power devices or light emitting diodes (LEDs). The amount is increasing. However, when the semiconductor element is exposed to a high temperature environment for a long time, it cannot perform its original function and its life is shortened. Therefore, the die bond material is required to have high thermal conductivity in order to efficiently release the heat generated from the semiconductor element to the supporting member, and the required level thereof is continuously increasing.
　導電性接着剤において、上述の要請から熱伝導性を向上させるために、導電性フィラーとして、従来から用いられていたマイクロメートルオーダーの金属粒子に加え、ナノメートルオーダーの金属粒子を用いる技術が報告されている。 In the conductive adhesive, in order to improve the thermal conductivity from the above requirements, in addition to the conventionally used micrometer-order metal particles, as a conductive filler, a technology using nanometer-order metal particles is reported. Has been done.
　例えば、特許文献１において、平均粒子径が２～２０μｍ、タップ密度（ＴＤ）が２．０～７．０ｇ／ｃｍ３、かつ、炭素含有化合物の含有割合が０．５質量％以下であるフレーク状銀粉と、平均粒子径が１０～５００ｎｍである銀ナノ粒子と、熱硬化性樹脂と、を含有することを特徴とする導電性ペーストが報告されている。 For example, in Patent Document 1, flakes having an average particle diameter of 2 to 20 μm, a tap density (TD) of 2.0 to 7.0 g/cm 3 , and a carbon-containing compound content of 0.5 mass% or less. It has been reported that a conductive paste is characterized by containing a granular silver powder, silver nanoparticles having an average particle diameter of 10 to 500 nm, and a thermosetting resin.
　また、特許文献２において、銀粉、銀微粒子、脂肪酸銀、及びアミンを含み、前記銀粉は、平均粒子径が０．３μｍ～１００μｍであり、前記銀微粒子は、１次粒子の平均粒子径が５０～１５０ｎｍであり、結晶子径が２０～５０ｎｍであり、かつ、結晶子径に対する平均粒子径の比が１～７．５であり、さらに、銀レジネートを含む、熱伝導性組成物が報告されている。 Further, in Patent Document 2, silver powder, silver fine particles, fatty acid silver, and amine are included, and the silver powder has an average particle diameter of 0.3 μm to 100 μm, and the silver fine particles have an average primary particle diameter of 50. To 150 nm, the crystallite size is 20 to 50 nm, the ratio of the average particle size to the crystallite size is 1 to 7.5, and further, a thermally conductive composition containing silver resinate is reported. ing.
日本国特開２０１５－１６２３９２号公報Japanese Patent Laid-Open No. 2015-162392 日本国特許第５８７２５４５号公報Japanese Patent No. 5782545
　先述のようなマイクロメートルオーダーの金属粒子にナノメートルオーダーの金属粒子を加えた導電性接着剤組成物の硬化物（以下、接着剤層ともいう）は、緻密な焼結構造を形成しているが、それでもなおその硬化物中には空隙が存在する。このような硬化物が上記のような半導体素子の発熱による温度変化を繰り返し受けた場合、ネッキング構造を形成していた金属が空隙に接する面積を減らして表面エネルギーを低下させる方向に移動し、その結果金属が成長する場合がある。 A cured product (hereinafter, also referred to as an adhesive layer) of a conductive adhesive composition in which metal particles of nanometer order are added to metal particles of micrometer order as described above (hereinafter, also referred to as an adhesive layer) forms a dense sintered structure. However, voids are still present in the cured product. When such a cured product is repeatedly subjected to temperature change due to heat generation of the semiconductor element as described above, the metal forming the necking structure moves in a direction of decreasing the surface energy by reducing the area in contact with the void, As a result, the metal may grow.
　一般に、マイクロメートルオーダーの金属粒子にナノメートルオーダーの金属粒子を加えた導電性接着剤組成物の硬化物は、その緻密な結晶構造に起因して応力緩和性能が低い。そのうえ、上記のような金属の成長が生じると、金属の移動に伴い接着界面付近に大きな空隙が生じること等に起因し、応力緩和性能がさらに低下することとなる。この場合、被接着材料同士の線熱膨張率の差により生じる応力によって、被接着材料の剥離が生じやすくなるという問題がある。 Generally, a cured product of a conductive adhesive composition obtained by adding nanometer-order metal particles to micrometer-order metal particles has low stress relaxation performance due to its dense crystal structure. In addition, when the metal grows as described above, the stress relaxation performance is further deteriorated due to the formation of large voids in the vicinity of the bonding interface as the metal moves. In this case, there is a problem that the material to be adhered is likely to be peeled off due to the stress generated by the difference in the coefficient of linear thermal expansion between the materials to be adhered.
　また、導電性接着剤組成物においては導電性や熱伝導率を向上させるために、導電性接着剤組成物内の金属成分の含有率を高くして充填密度を高めることが行われている。上記特許文献１、及び特許文献２においても、導電性接着剤組成物の全体量に対して、マイクロメートルオーダー、ナノメートルオーダーの金属粒子をあわせて８０％以上含むような導電性接着剤組成物が実施例において開示されている。しかし、このような金属含有率が高い導電性接着剤組成物の硬化物は一般的に応力緩和性能が低く、上述の剥離が特に生じやすい。 In addition, in the conductive adhesive composition, in order to improve conductivity and thermal conductivity, the content of the metal component in the conductive adhesive composition is increased to increase the packing density. Also in Patent Document 1 and Patent Document 2 described above, a conductive adhesive composition containing a total of 80% or more of metal particles of micrometer order and nanometer order with respect to the total amount of the conductive adhesive composition. Are disclosed in the examples. However, such a cured product of a conductive adhesive composition having a high metal content generally has low stress relaxation performance, and the above-mentioned peeling is particularly likely to occur.
　また、接着剤層を薄くすると、応力緩和性能が低くなるため、上述の剥離が生じやすくなる。しかし、近年においては、半導体素子の発熱量の増加により、放熱効率のより一層の向上が求められることから、接着剤層の薄層化への要請が強い。 Also, if the adhesive layer is made thinner, the stress relaxation performance will be lower, and the above-mentioned peeling will occur more easily. However, in recent years, there has been a strong demand for a thinner adhesive layer because the heat dissipation amount of the semiconductor element is increased and further improvement of heat dissipation efficiency is required.
　したがって、繰り返しの温度変化に起因する被接着材料の剥離の抑制性能が高く、接着剤層を薄層化した場合においても剥離を十分に抑制できるような導電性接着剤組成物が望まれている。 Therefore, there is a demand for a conductive adhesive composition that has high performance of suppressing peeling of the material to be adhered due to repeated temperature changes and that can sufficiently suppress peeling even when the adhesive layer is made thin. ..
　本発明は、上記課題に鑑みて発明されたものであり、その目的は、熱伝導性に優れ、さらに、繰り返し温度変化を受けた場合にも被接着材料の剥離を十分に抑制できる導電性接着剤組成物を提供することである。 The present invention has been invented in view of the above problems, and an object thereof is excellent in thermal conductivity, and further, conductive adhesion capable of sufficiently suppressing peeling of the adherend material even when subjected to repeated temperature changes. To provide an agent composition.
　本発明者らは、鋭意研究した結果、平均粒子径０．５～１０μｍの金属粒子と平均粒子径１０～２００ｎｍの銀粒子とを含む導電性フィラーと、平均粒子径２～１４μｍの、融点が１３０～２５０℃である熱可塑性樹脂の粒子とを含有する導電性接着剤組成物によって、熱伝導性に優れ、かつ繰り返し温度変化を受けた場合にも被接着材料の剥離が生じにくい接着を実現できることを見出し、本発明を完成するに至った。 As a result of earnest studies, the present inventors have found that a conductive filler containing metal particles having an average particle diameter of 0.5 to 10 μm and silver particles having an average particle diameter of 10 to 200 nm and an average particle diameter of 2 to 14 μm and a melting point of A conductive adhesive composition containing particles of a thermoplastic resin having a temperature of 130 to 250° C. realizes an adhesive having excellent thermal conductivity and in which peeling of a material to be adhered does not easily occur even when subjected to repeated temperature changes. They have found that they can do so and have completed the present invention.
　すなわち、本発明の導電性接着剤組成物は平均粒子径０．５～１０μｍの金属粒子（ａ１）と平均粒子径１０～２００ｎｍの銀粒子（ａ２）とを含む導電性フィラー（Ａ）と、平均粒子径２～１４μｍの熱可塑性樹脂の粒子（Ｂ）と、を含有し、熱可塑性樹脂の融点が、１３０～２５０℃である。 That is, the conductive adhesive composition of the present invention comprises a conductive filler (A) containing metal particles (a1) having an average particle diameter of 0.5 to 10 μm and silver particles (a2) having an average particle diameter of 10 to 200 nm, The thermoplastic resin particles (B) having an average particle diameter of 2 to 14 μm are contained, and the melting point of the thermoplastic resin is 130 to 250° C.
　本発明の一態様に係る導電性接着剤組成物は、金属粒子（ａ１）の主成分が銀である。 In the conductive adhesive composition according to one aspect of the present invention, the main component of the metal particles (a1) is silver.
　本発明の一態様に係る導電性接着剤組成物は、導電性接着剤組成物の全体量に対して、金属粒子（ａ１）を３５～８５質量％、銀粒子（ａ２）を５～５０質量％の範囲で含有する。 The conductive adhesive composition according to one aspect of the present invention contains 35 to 85% by mass of metal particles (a1) and 5 to 50% by mass of silver particles (a2) based on the total amount of the conductive adhesive composition. It is contained in the range of %.
　本発明の一態様に係る導電性接着剤組成物は、金属粒子（ａ１）と銀粒子（ａ２）との含有比率が、質量比で９５：５～４０：６０の範囲である。 In the conductive adhesive composition according to one aspect of the present invention, the content ratio of the metal particles (a1) and the silver particles (a2) is in the range of 95:5 to 40:60 by mass ratio.
　本発明の一態様に係る導電性接着剤組成物は、導電性接着剤組成物の全体量に対して、熱可塑性樹脂の粒子（Ｂ）を０．１～１０質量％の範囲で含有する。 The conductive adhesive composition according to one aspect of the present invention contains the thermoplastic resin particles (B) in the range of 0.1 to 10 mass% with respect to the total amount of the conductive adhesive composition.
　また、本発明の導電性接着剤硬化物は、前記いずれか１の導電性接着剤組成物を硬化したものである。 Further, the conductive adhesive cured product of the present invention is a cured product of any one of the conductive adhesive compositions described above.
　また、本発明の電子機器は、前記いずれか１の導電性接着剤組成物を部品の接着に使用したものである。 The electronic device of the present invention uses the conductive adhesive composition according to any one of the above for bonding components.
　本発明の導電性接着剤組成物は、平均粒子径０．５～１０μｍの金属粒子（ａ１）と、平均粒子径１０～２００ｎｍの銀粒子（ａ２）とを含む導電性フィラー（Ａ）を含有することにより熱伝導率を向上させている。また、平均粒子径２～１４μｍの、融点が１３０～２５０℃の熱可塑性樹脂の粒子（Ｂ）を含有することにより、ナノメートルオーダーの銀粒子を含有することに起因する、繰り返し温度変化を受けた場合における被接着材料の剥離発生の可能性の上昇を抑制している。このことから、本発明の導電性接着剤は、熱伝導性に優れ、さらに、繰り返し温度変化を受けた場合の被接着材料の剥離が十分に抑制されたものである。 The conductive adhesive composition of the present invention contains a conductive filler (A) containing metal particles (a1) having an average particle diameter of 0.5 to 10 μm and silver particles (a2) having an average particle diameter of 10 to 200 nm. By doing so, the thermal conductivity is improved. Further, the inclusion of the thermoplastic resin particles (B) having an average particle diameter of 2 to 14 μm and a melting point of 130 to 250° C. causes repeated temperature changes due to the inclusion of nanometer-order silver particles. In this case, the increase in the possibility of peeling of the adherend material is suppressed. From this, the conductive adhesive of the present invention has excellent thermal conductivity, and further, peeling of the adherend material when subjected to repeated temperature changes is sufficiently suppressed.
　以下に、本発明を実施するための形態を説明するが、本発明は以下の実施形態に限定されるものではなく、本発明の要旨を逸脱しない範囲において、任意に変形して実施することができる。また、本明細書において数値範囲を示す「～」とは、その前後に記載された数値を下限値、及び上限値として含む意味で使用される。 Hereinafter, modes for carrying out the present invention will be described, but the present invention is not limited to the following embodiments, and may be arbitrarily modified and carried out without departing from the scope of the present invention. it can. Further, in the present specification, “to” indicating a numerical range is used to mean that numerical values described before and after the numerical range are included as a lower limit value and an upper limit value.
　また、本明細書において金属粒子（ａ１）および熱可塑性樹脂の粒子（Ｂ）の平均粒子径はレーザー回折・散乱式粒度分析計を用いて測定された粒子径分布の５０％平均粒子径（Ｄ５０）とする。当該平均粒子径は、例えば、日機装株式会社製のレーザー回折・散乱式粒度分析計ＭＴ－３０００を用いて測定することができる。銀粒子（ａ２）の平均粒子径は動的光散乱法を用いて測定された粒子径分布の５０％平均粒子径（Ｄ５０）とする。当該平均粒子径は、例えば、日機装株式会社製のナノトラック粒子分布測定装置を用いて測定することができる。 In the present specification, the average particle size of the metal particles (a1) and the particles of the thermoplastic resin (B) is 50% of the particle size distribution measured using a laser diffraction/scattering particle size analyzer (D50). ). The average particle diameter can be measured using, for example, a laser diffraction/scattering particle size analyzer MT-3000 manufactured by Nikkiso Co., Ltd. The average particle size of the silver particles (a2) is the 50% average particle size (D50) of the particle size distribution measured using the dynamic light scattering method. The average particle diameter can be measured using, for example, a Nanotrac particle distribution measuring device manufactured by Nikkiso Co., Ltd.
　［導電性フィラー（Ａ）］
　本発明の実施形態における導電性フィラー（Ａ）は、平均粒子径０．５～１０μｍの金属粒子（ａ１）と、平均粒子径１０～２００ｎｍの銀粒子（ａ２）とを含むものである。 [Conductive filler (A)]
The conductive filler (A) in the embodiment of the present invention contains metal particles (a1) having an average particle diameter of 0.5 to 10 μm and silver particles (a2) having an average particle diameter of 10 to 200 nm.
　＜金属粒子（ａ１）＞
　本発明の実施形態における金属粒子（ａ１）の平均粒子径は０．５μｍ以上であり、好ましくは０．６μｍ以上であり、より好ましくは０．７μｍ以上であり、さらに好ましくは０．８μｍ以上である。また、本発明の実施形態における金属粒子（ａ１）の平均粒子径は１０μｍ以下であり、好ましくは８μｍ以下であり、より好ましくは７μｍ以下であり、さらに好ましくは６μｍ以下である。 <Metal particles (a1)>
The average particle diameter of the metal particles (a1) in the embodiment of the present invention is 0.5 μm or more, preferably 0.6 μm or more, more preferably 0.7 μm or more, and further preferably 0.8 μm or more. is there. The average particle size of the metal particles (a1) in the embodiment of the present invention is 10 μm or less, preferably 8 μm or less, more preferably 7 μm or less, and further preferably 6 μm or less.
　また、本発明の実施形態における金属粒子（ａ１）の平均粒子径は０．５～１０μｍであり、好ましくは０．６～８μｍであり、より好ましくは０．７～７μｍ、さらに好ましくは０．８～６μｍである。 Further, the average particle diameter of the metal particles (a1) in the embodiment of the present invention is 0.5 to 10 μm, preferably 0.6 to 8 μm, more preferably 0.7 to 7 μm, and further preferably 0.1. It is 8 to 6 μm.
　金属粒子（ａ１）の平均粒子径が０．５μｍ未満であると、導電性接着剤組成物の硬化後の収縮が抑制されなくなるため被接着材料との密着性が低下してしまう。金属粒子（ａ１）の平均粒子径が１０μｍを超えると金属粒子（ａ１）の焼結が進みにくく被接着材料との密着性が低下してしまう。 When the average particle size of the metal particles (a1) is less than 0.5 μm, the contraction of the conductive adhesive composition after curing is not suppressed, so that the adhesion with the adherend material is deteriorated. When the average particle diameter of the metal particles (a1) exceeds 10 μm, the sintering of the metal particles (a1) is difficult to proceed and the adhesion with the adherend material is reduced.
　本発明の実施形態における金属粒子（ａ１）は、導電性接着剤における導電性に寄与する成分であれば特に制限されない。中でも、金属やカーボンナノチューブ等が好ましい。 The metal particles (a1) in the embodiment of the present invention are not particularly limited as long as they are components that contribute to the conductivity of the conductive adhesive. Of these, metals and carbon nanotubes are preferable.
　金属としては、一般的な導体として扱われる金属の粉末を利用することができる。例えば、銀、銅、金、ニッケル、アルミニウム、クロム、白金、パラジウム、タングステン、モリブデン等の単体、これら２種以上の金属からなる合金、これら金属のコーティング品、これら金属の酸化物、あるいはこれら金属の化合物で良好な導電性を有するもの等が挙げられる。中でも、酸化しづらく熱伝導性が高いことから、銀を主成分とする金属がより好ましい。ここで「主成分」とは、金属粒子を構成する成分の中で、最も含有量の多い成分のことをさす。 As the metal, metal powder that is treated as a general conductor can be used. For example, simple substances such as silver, copper, gold, nickel, aluminum, chromium, platinum, palladium, tungsten, molybdenum, alloys composed of two or more kinds of these metals, coated products of these metals, oxides of these metals, or these metals. Examples of compounds having good conductivity are listed. Among them, a metal containing silver as a main component is more preferable because it is difficult to oxidize and has high thermal conductivity. Here, the "main component" refers to the component with the highest content among the components constituting the metal particles.
　金属粒子（ａ１）のタップ密度は、特に限定されないが、被接着材料への接着強度を確保するために、４ｇ／ｃｍ３以上であることが好ましく、５ｇ／ｃｍ３以上であることがより好ましく、５．５ｇ／ｃｍ３以上であることがさらに好ましい。また、導電性接着剤組成物を長期保管した際に金属粒子（ａ１）が沈降し不安定になることを防ぐために、８ｇ／ｃｍ３以下であることが好ましく、７．５ｇ／ｃｍ３以下であることがより好ましく、７ｇ／ｃｍ３以下であることがさらに好ましい。タップ密度は、例えばＪＩＳ規格Ｚ２５１２：２０１２の金属粉－タップ密度測定方法により測定され算出される。 The tap density of the metal particles (a1) is not particularly limited, but is preferably 4 g/cm 3 or more, and more preferably 5 g/cm 3 or more in order to secure the adhesive strength to the adherend material. More preferably, it is 5.5 g/cm 3 or more. Further, in order to prevent the metal particles (a1) from settling and becoming unstable when the conductive adhesive composition is stored for a long time, it is preferably 8 g/cm 3 or less, and 7.5 g/cm 3 or less. It is more preferable that the amount is 7 g/cm 3 or less. The tap density is measured and calculated by a metal powder-tap density measuring method of JIS standard Z2512:2012, for example.
　金属粒子（ａ１）の比表面積は、特に限定されないが、０．１ｍ２／ｇ以上であることが好ましく、より好ましくは０．２ｍ２／ｇ以上であり、さらに好ましくは０．３ｍ２／ｇ以上である。また、金属粒子（ａ１）の比表面積は、３ｍ２／ｇ以下であることが好ましく、より好ましくは２ｍ２／ｇ以下であり、さらに好ましくは１ｍ２／ｇ以下である。 The specific surface area of the metal particles (a1) is not particularly limited, but is preferably 0.1 m 2 /g or more, more preferably 0.2 m 2 /g or more, further preferably 0.3 m 2 /g. That is all. The specific surface area of the metal particles (a1) is preferably 3 m 2 /g or less, more preferably 2 m 2 /g or less, and further preferably 1 m 2 /g or less.
　また、金属粒子（ａ１）の比表面積は、０．１～３ｍ２／ｇであることが好ましく、より好ましくは０．２～２ｍ２／ｇであり、さらに好ましくは０．３～１ｍ２／ｇである。 The specific surface area of the metal particles (a1) is preferably 0.1 ~ 3m 2 / g, more preferably 0.2 ~ 2m 2 / g, more preferably 0.3 ~ 1 m 2 / It is g.
　金属粒子（ａ１）の比表面積が０．１ｍ２／ｇ以上であることにより、被接着材料に接する金属粒子（ａ１）の表面積が確保できる。また、金属粒子（ａ１）の比表面積が３ｍ２／ｇ以下であることにより、導電性組成物に添加する溶剤量を少なくできる。 When the specific surface area of the metal particles (a1) is 0.1 m 2 /g or more, the surface area of the metal particles (a1) in contact with the adherend material can be secured. Moreover, when the specific surface area of the metal particles (a1) is 3 m 2 /g or less, the amount of the solvent added to the conductive composition can be reduced.
　金属粒子（ａ１）の形状は特に限定されず、例えば、球状、フレーク状、プレート状、箔状および樹枝状等が挙げられる。一般的にはフレーク状または球状が選択される。また、金属粒子（ａ１）には、単一の金属からなる粒子のほか、２種以上の金属からなる表面被覆された金属粒子、またはこれらの混合物を用いることができる。 The shape of the metal particles (a1) is not particularly limited, and examples thereof include spherical shape, flake shape, plate shape, foil shape, and dendritic shape. In general, flakes or spheres are selected. As the metal particles (a1), not only particles made of a single metal but also surface-coated metal particles made of two or more kinds of metals, or a mixture thereof can be used.
　＜銀粒子（ａ２）＞
　本発明の実施形態における銀粒子（ａ２）の平均粒子径は１０ｎｍ以上であり、好ましくは２０ｎｍ以上であり、より好ましくは３０ｎｍ以上であり、更に好ましくは４０ｎｍ以上である。また、本発明の実施形態における銀粒子（ａ２）の平均粒子径は２００ｎｍ以下であり、好ましくは１８０ｎｍ以下であり、より好ましくは１７０ｎｍ以下であり、更に好ましくは１６０ｎｍ以下である。 <Silver particles (a2)>
The average particle diameter of the silver particles (a2) in the embodiment of the present invention is 10 nm or more, preferably 20 nm or more, more preferably 30 nm or more, and further preferably 40 nm or more. The average particle size of the silver particles (a2) in the embodiment of the present invention is 200 nm or less, preferably 180 nm or less, more preferably 170 nm or less, and further preferably 160 nm or less.
　本発明の実施形態における銀粒子（ａ２）の平均粒子径は１０～２００ｎｍであり、好ましくは２０～１８０ｎｍであり、より好ましくは３０～１７０ｎｍであり、更に好ましくは４０～１６０ｎｍである。 The average particle diameter of the silver particles (a2) in the embodiment of the present invention is 10 to 200 nm, preferably 20 to 180 nm, more preferably 30 to 170 nm, further preferably 40 to 160 nm.
　銀粒子（ａ２）の平均粒子径が１０ｎｍ未満であると、銀粒子を被覆する有機物の除去が難しくなり焼結が進みにくい。銀粒子（ａ２）の平均粒子径が２００ｎｍを超えると比表面積が小さくなり銀粒子の焼結が進みにくい。 When the average particle size of the silver particles (a2) is less than 10 nm, it is difficult to remove the organic material coating the silver particles, and it is difficult to proceed with sintering. When the average particle diameter of the silver particles (a2) exceeds 200 nm, the specific surface area becomes small and it is difficult to sinter the silver particles.
　銀粒子（ａ２）のタップ密度は、特に限定されないが、銀粒子の接触点を増やし焼結しやすくするために、４ｇ／ｃｍ３以上であることが好ましく、５ｇ／ｃｍ３以上であることがより好ましく、５．５ｇ／ｃｍ３以上であることがさらに好ましい。また、導電性接着剤組成物を長期保管した際に銀粒子（ａ２）が沈降し不安定になることを防ぐために、８ｇ／ｃｍ３以下であることが好ましく、７．５ｇ／ｃｍ３以下であることがより好ましく、７ｇ／ｃｍ３以下であることがさらに好ましい。タップ密度は、例えばＪＩＳ規格Ｚ２５１２：２０１２の金属粉－タップ密度測定方法により測定され算出される。 The tap density of the silver particles (a2) is not particularly limited, but is preferably 4 g/cm 3 or more, and preferably 5 g/cm 3 or more in order to increase the contact points of the silver particles and facilitate sintering. More preferably, it is more preferably 5.5 g/cm 3 or more. Further, in order to prevent the silver particles (a2) from settling and becoming unstable when the conductive adhesive composition is stored for a long time, it is preferably 8 g/cm 3 or less, and 7.5 g/cm 3 or less. It is more preferable that the amount is 7 g/cm 3 or less. The tap density is measured and calculated by a metal powder-tap density measuring method of JIS standard Z2512:2012, for example.
　銀粒子（ａ２）の形状は特に限定されず、例えば、球状、キュービック状、ロッド状等が挙げられる。また、銀粒子（ａ２）には、純銀粒子のほか、銀で表面被覆された金属粒子、またはこれらの混合物を用いることができる。 The shape of the silver particles (a2) is not particularly limited, and examples thereof include a spherical shape, a cubic shape, and a rod shape. As the silver particles (a2), in addition to pure silver particles, metal particles whose surface is coated with silver, or a mixture thereof can be used.
　銀粒子（ａ２）は、その表面がコーティング剤で被覆されていてもよい。用いるコーティング剤や被覆方法は特に限定されないが、例えば、アミンまたはカルボン酸の官能基を含むコーティング剤が挙げられる。中でも、カルボン酸の官能基を含むコーティング剤を用いることによって、導電性接着剤組成物の放熱性をより一層向上させることができるため好ましい。 The surface of the silver particles (a2) may be coated with a coating agent. The coating agent and the coating method used are not particularly limited, and examples thereof include a coating agent containing a functional group of amine or carboxylic acid. Above all, it is preferable to use a coating agent containing a carboxylic acid functional group, because the heat dissipation of the conductive adhesive composition can be further improved.
　また、不活性ガス雰囲気下での導電性接着剤組成物の硬化を容易にするためには、コーティング剤は加熱時に除去されやすいものが望ましく、官能基はカルボン酸であることが好ましい。カルボン酸の官能基を含むコーティング剤としては、特に限定されず、例えば、モノカルボン酸、ポリカルボン酸およびオキシカルボン酸等が挙げられる。コーティング剤に含まれるカルボン酸は２種以上の混合物であってもよい。また、コーティング剤は炭素数１２～２４の飽和脂肪酸または不飽和脂肪酸である高級脂肪酸が好ましい。 Further, in order to facilitate the curing of the conductive adhesive composition in an inert gas atmosphere, the coating agent is preferably one that is easily removed when heated, and the functional group is preferably a carboxylic acid. The coating agent containing a functional group of carboxylic acid is not particularly limited, and examples thereof include monocarboxylic acid, polycarboxylic acid and oxycarboxylic acid. The carboxylic acid contained in the coating agent may be a mixture of two or more kinds. Further, the coating agent is preferably a higher fatty acid which is a saturated fatty acid having 12 to 24 carbon atoms or an unsaturated fatty acid.
　銀粒子（ａ２）の表面をコーティング剤で被覆する方法としては、例えば、両者をミキサー中で撹拌、混練する方法、銀粒子（ａ２）にカルボン酸の溶液を含浸して溶剤を揮発させる方法等の公知の方法が挙げられる。 Examples of the method of coating the surface of the silver particles (a2) with a coating agent include a method of stirring and kneading the both in a mixer, a method of impregnating the silver particles (a2) with a solution of a carboxylic acid and volatilizing the solvent. The well-known method of is mentioned.
　本発明の実施形態の導電性接着剤組成物において、導電性や熱伝導率の向上、及び塗工性の確保のために、金属粒子（ａ１）の含有量は導電性接着剤組成物の全体量に対して３５質量％以上であることが好ましく、４０質量％以上であることがより好ましく、４５質量％以上であることがさらに好ましい。また、金属粒子（ａ１）の含有量は導電性接着剤組成物の全体量に対して８５質量％以下であることが好ましく、７５質量％以下であることがより好ましく、６５質量％以下であることがさらに好ましい。 In the conductive adhesive composition of the embodiment of the present invention, the content of the metal particles (a1) is the whole of the conductive adhesive composition in order to improve conductivity and thermal conductivity and to secure coatability. The amount is preferably 35% by mass or more, more preferably 40% by mass or more, and further preferably 45% by mass or more. The content of the metal particles (a1) is preferably 85% by mass or less, more preferably 75% by mass or less, and 65% by mass or less with respect to the total amount of the conductive adhesive composition. Is more preferable.
　本発明の実施形態の導電性接着剤組成物において、金属粒子（ａ１）の含有量は導電性接着剤組成物の全体量に対して３５～８５質量％であることが好ましく、４０～７５質量％であることがより好ましく、４５～６５質量％であることがさらに好ましい。 In the conductive adhesive composition of the embodiment of the present invention, the content of the metal particles (a1) is preferably 35 to 85 mass% with respect to the total amount of the conductive adhesive composition, and 40 to 75 mass. %, more preferably 45 to 65% by mass.
　また、銀粒子（ａ２）の含有量は、導電性接着剤組成物の全体量に対して５質量％以上であることが好ましく、１０質量％以上であることがより好ましく、１５質量％以上であることがさらに好ましい。また、銀粒子（ａ２）の含有量は、導電性接着剤組成物の全体量に対して５０質量％以下であることが好ましく、４０質量％以下であることがより好ましく、３５質量％以下であることがさらに好ましい。 The content of the silver particles (a2) is preferably 5% by mass or more, more preferably 10% by mass or more, and 15% by mass or more with respect to the total amount of the conductive adhesive composition. It is more preferable that there is. The content of the silver particles (a2) is preferably 50% by mass or less, more preferably 40% by mass or less, and 35% by mass or less with respect to the total amount of the conductive adhesive composition. It is more preferable that there is.
　また、銀粒子（ａ２）の含有量は、導電性接着剤組成物の全体量に対して５～５０質量％であることが好ましく、１０～４０質量％であることがより好ましく、１５～３５質量％であることがさらに好ましい。 Further, the content of the silver particles (a2) is preferably 5 to 50% by mass, more preferably 10 to 40% by mass, and 15 to 35% based on the total amount of the conductive adhesive composition. More preferably, it is mass %.
　また、本発明の実施形態の導電性接着剤組成物において、熱伝導率を向上させるために、金属粒子（ａ１）と銀粒子（ａ２）との含有比率は、質量比で９５：５～４０：６０の範囲であることが好ましく、９０：１０～５０：５０の範囲であることがより好ましく、８５：１５～６０：４０の範囲であることがさらに好ましい。 Further, in the conductive adhesive composition of the embodiment of the present invention, in order to improve the thermal conductivity, the content ratio of the metal particles (a1) and the silver particles (a2) is 95:5 to 40 by mass ratio. :60 is preferable, 90:10 to 50:50 is more preferable, and 85:15 to 60:40 is further preferable.
　なお、本発明の実施形態の導電性接着剤組成物においては、本発明の効果を損なわない限りにおいて、他の導電性フィラーを併用することができる。そのような導電性フィラーとしては、導電性を有するものであれば特に限定はされないが、例えばカーボンナノチューブなどが挙げられる。 Note that, in the conductive adhesive composition of the embodiment of the present invention, other conductive fillers can be used in combination as long as the effect of the present invention is not impaired. The conductive filler is not particularly limited as long as it has conductivity, and examples thereof include carbon nanotubes.
　［熱可塑性樹脂の粒子（Ｂ）］
　本発明の実施形態の導電性接着剤組成物は、平均粒子径２～１４μｍ、融点が１３０～２５０℃の熱可塑性樹脂の粒子（Ｂ）をさらに含有する。 [Thermoplastic resin particles (B)]
The conductive adhesive composition according to the embodiment of the present invention further contains particles (B) of a thermoplastic resin having an average particle diameter of 2 to 14 μm and a melting point of 130 to 250° C.
　通常、本発明のようにナノメートルオーダーの銀粒子を含有する導電性接着剤組成物の硬化物（以下、単に「導電性接着剤硬化物」ともいう）は、緻密な構造を有するため応力緩和性能が低い。さらに、繰り返しの温度変化を受けることにより金属が成長し、このことによって応力緩和性能がさらに低下する。そのため、ナノメートルオーダーの銀粒子を含有する導電性接着剤組成物による接着では、被接着材料同士の線熱膨張率の差により生じる応力によって、被接着材料の剥離が生じやすい。 Usually, a cured product of a conductive adhesive composition containing silver particles of the nanometer order as in the present invention (hereinafter, also simply referred to as "conductive adhesive cured product") has a dense structure, so that stress relaxation is achieved. Poor performance. Further, the metal is grown by being subjected to repeated temperature changes, which further reduces the stress relaxation performance. Therefore, in the adhesion using the conductive adhesive composition containing silver particles in the order of nanometers, the material to be adhered is likely to be peeled off due to the stress caused by the difference in the coefficient of linear thermal expansion between the materials to be adhered.
　しかし、熱可塑性樹脂の粒子（Ｂ）を含有する本発明の実施形態の導電性接着剤組成物では、熱を加えて硬化させる際に、熱可塑性樹脂の粒子（Ｂ）が溶融し、導電性接着剤硬化物内の空隙を充填する。このことにより、導電性接着剤硬化物内での金属の移動が妨げられ、上記のように、金属の成長によって応力による被接着材料の剥離が生じやすくなることを防いでいるものと考えられる。 However, in the conductive adhesive composition of the embodiment of the present invention containing the thermoplastic resin particles (B), when the thermoplastic resin particles (B) are cured by heating, the thermoplastic resin particles (B) melt and Fill the voids in the cured adhesive. It is considered that this prevents the movement of the metal in the cured product of the conductive adhesive and prevents the peeling of the adherend material due to the stress due to the growth of the metal as described above.
　他にも、導電性接着剤硬化物内の空隙に充填された熱可塑性樹脂が弾性変形することによって応力を緩和することが可能となり、導電性接着剤硬化物の応力緩和性能が向上すること、また、熱可塑性樹脂が導電性接着剤硬化物と被接着材料の接着界面に存在する空隙を充填することにより、接着強度が向上することも、繰り返しの温度変化による剥離の抑制に寄与していると考えられる。 In addition, the thermoplastic resin filled in the voids in the conductive adhesive cured product is capable of relieving stress by elastic deformation, improving the stress relaxation performance of the conductive adhesive cured product, Further, the thermoplastic resin fills the voids existing at the adhesive interface between the conductive adhesive cured product and the adherend material, which improves the adhesive strength, which also contributes to the suppression of peeling due to repeated temperature changes. it is conceivable that.
　また、熱可塑性樹脂の粒子（Ｂ）には、導電性接着剤硬化物における亀裂の発生や進展を抑制する効果もある。本発明の実施形態の導電性接着剤組成物の硬化物の内部には溶融した熱可塑性樹脂が分散しているが、この樹脂が、亀裂先端の応力を分散する効果、亀裂にぶつかって亀裂の進展を止める効果、変形して亀裂進展のエネルギーを消費させる効果などを奏することにより、亀裂の発生及び進展を抑制することができる。 Also, the thermoplastic resin particles (B) have an effect of suppressing the occurrence or development of cracks in the cured conductive adhesive. Although the molten thermoplastic resin is dispersed inside the cured product of the conductive adhesive composition of the embodiment of the present invention, this resin has the effect of dispersing the stress at the crack tip, causing a crack by hitting the crack. By producing the effect of stopping the progress, the effect of deforming and consuming the energy of the crack progress, the generation and progress of the crack can be suppressed.
　上述の剥離抑制の効果を得るには、熱可塑性樹脂の粒子（Ｂ）が導電性接着剤組成物の硬化の際に溶融して、導電性接着剤硬化物内の空隙を充填する必要がある。導電性接着剤組成物の硬化の際の適切な加熱温度は、例えば導電性フィラー（Ａ）の種類等、様々な条件により変化するが、通常１３０～２５０℃である。したがって本発明の実施形態においては、導電性接着剤組成物の硬化の際に熱硬化性樹脂の粒子（Ｂ）が十分に溶融するように、熱可塑性樹脂の粒子（Ｂ）の融点は２５０℃以下とする。また、熱可塑性樹脂の粒子（Ｂ）の融点は、２３０℃以下が好ましく、２００℃以下がより好ましい。 In order to obtain the above-described effect of suppressing peeling, it is necessary that the particles (B) of the thermoplastic resin be melted during the curing of the conductive adhesive composition to fill the voids in the cured conductive adhesive. .. The appropriate heating temperature for curing the conductive adhesive composition varies depending on various conditions such as the type of the conductive filler (A), but is usually 130 to 250°C. Therefore, in the embodiment of the present invention, the melting point of the thermoplastic resin particles (B) is 250° C. so that the thermosetting resin particles (B) are sufficiently melted when the conductive adhesive composition is cured. Below. Further, the melting point of the particles (B) of the thermoplastic resin is preferably 230°C or lower, more preferably 200°C or lower.
　一方、導電性接着剤組成物の硬化の際に導電性フィラー（Ａ）の焼結より先に熱可塑性樹脂の粒子（Ｂ）が溶融すると、導電性フィラー（Ａ）の焼結を妨げる恐れがある。導電性フィラー（Ａ）の焼結温度はその種類等によっても異なるが、通常は１３０℃以下である。したがって本発明の実施形態においては、導電性フィラー（Ａ）の焼結より先に熱可塑性樹脂の粒子（Ｂ）が溶融しないように、熱可塑性樹脂の粒子（Ｂ）の融点は１３０℃以上とする。また、熱可塑性樹脂の粒子（Ｂ）の融点は、１４０℃以上が好ましく、１５０℃以上がより好ましく、１６０℃以上がさらに好ましい。 On the other hand, when the particles (B) of the thermoplastic resin are melted prior to the sintering of the conductive filler (A) during the curing of the conductive adhesive composition, the sintering of the conductive filler (A) may be hindered. is there. The sintering temperature of the conductive filler (A) varies depending on its type and the like, but is usually 130° C. or lower. Therefore, in the embodiment of the present invention, the melting point of the thermoplastic resin particles (B) is 130° C. or higher so that the thermoplastic resin particles (B) are not melted before the sintering of the conductive filler (A). To do. Further, the melting point of the thermoplastic resin particles (B) is preferably 140° C. or higher, more preferably 150° C. or higher, and even more preferably 160° C. or higher.
　また、上述の剥離抑制の効果を得るには、熱可塑性樹脂の粒子（Ｂ）の平均粒子径も重要となる。
　熱可塑性樹脂の粒子（Ｂ）の平均粒子径が大きいと、同じ量での個数が少なくなり、応力を分散する効果が乏しくなる。また、熱可塑性樹脂の粒子（Ｂ）の平均粒子径が大きいと接着剤層の厚み方向に対しての樹脂粒子の存在比率が非常に高い箇所ができるが、このような箇所は接着剤層内の脆弱点になりえる。
　また、熱可塑性樹脂の粒子（Ｂ）の平均粒子径が大きすぎると、接着剤層を薄くできなくなり、半導体素子等の被着体から発生した熱を効率よく逃がせなくなるため、この観点からも熱可塑性樹脂の粒子（Ｂ）の平均粒子径が大きすぎることは好ましくない。
　上記より、熱可塑性樹脂の粒子（Ｂ）の平均粒子径は、１４μｍ以下とする。また、熱可塑性樹脂の粒子（Ｂ）の平均粒子径は、１３μｍ以下が好ましい。
　一方、平均粒子径が小さすぎると応力緩和の能力および亀裂進展抑制効果が乏しくなる。
　上記より、熱可塑性樹脂の粒子（Ｂ）の平均粒子径は、２μｍ以上とする。また、熱可塑性樹脂の粒子（Ｂ）の平均粒子径は、３μｍ以上が好ましい。 Further, in order to obtain the above-described effect of suppressing peeling, the average particle diameter of the thermoplastic resin particles (B) is also important.
When the average particle diameter of the thermoplastic resin particles (B) is large, the number of particles in the same amount is small, and the effect of dispersing stress becomes poor. Further, when the average particle diameter of the thermoplastic resin particles (B) is large, there are places where the ratio of resin particles existing in the thickness direction of the adhesive layer is very high. Can be a vulnerability.
Further, if the average particle diameter of the thermoplastic resin particles (B) is too large, the adhesive layer cannot be made thin, and the heat generated from the adherend such as a semiconductor element cannot be efficiently dissipated. It is not preferable that the average particle diameter of the particles (B) of the plastic resin is too large.
From the above, the average particle diameter of the thermoplastic resin particles (B) is 14 μm or less. The average particle diameter of the thermoplastic resin particles (B) is preferably 13 μm or less.
On the other hand, if the average particle size is too small, the stress relaxation ability and the crack growth suppressing effect become poor.
From the above, the average particle diameter of the thermoplastic resin particles (B) is 2 μm or more. The average particle size of the thermoplastic resin particles (B) is preferably 3 μm or more.
　本発明の実施形態における熱可塑性樹脂の粒子（Ｂ）としては、上記の融点及び平均粒子径の条件をみたす公知の樹脂の粒子であってよい。例えば、ナイロン１１、ナイロン１２、ナイロン６等の公知のポリアミド、ＡＳ樹脂、ＡＢＳ樹脂、ＡＥＳ樹脂、酢酸ビニル樹脂、ポリスチレン、ポリエチレン、ポリプロピレン、ポリ塩化ビニル、アクリル樹脂、メタクリル樹脂、ポリビニルアルコール樹脂、ポリビニルエーテル、ポリアセタール、ポリカーボネート、ポリエチレンテレフタレート、ポリブチレンテレフタレート、ポリビニルブチラール、ポリビニルホルマール、ポリスルホン、ポリエーテルスルホン、ポリイミド、フェノキシ樹脂ポリエーテルイミド、エチルセルロース、酢酸セルロース、各種のフッ素樹脂、ポリオレフィンエラストマー、シリコーン樹脂等の粒子が挙げられ、これらの混合物や共重合体（コポリマー）であっても良い。 The thermoplastic resin particles (B) in the embodiment of the present invention may be known resin particles satisfying the above-mentioned conditions of melting point and average particle diameter. For example, known polyamides such as nylon 11, nylon 12, nylon 6, AS resin, ABS resin, AES resin, vinyl acetate resin, polystyrene, polyethylene, polypropylene, polyvinyl chloride, acrylic resin, methacrylic resin, polyvinyl alcohol resin, polyvinyl Ether, polyacetal, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyvinyl butyral, polyvinyl formal, polysulfone, polyether sulfone, polyimide, phenoxy resin polyetherimide, ethyl cellulose, cellulose acetate, various fluororesins, polyolefin elastomers, silicone resins, etc. Examples thereof include particles, and a mixture or copolymer of these may be used.
　本発明の実施形態における熱可塑性樹脂の粒子（Ｂ）の形状は特に限定されず、例えば、略球状、立方体状、円柱状、角柱状、円錐状、角錐状、フレーク状、箔状および樹枝状等が挙げられるが、略球状、立方体状が好ましい。 The shape of the particles (B) of the thermoplastic resin in the embodiment of the present invention is not particularly limited, and examples thereof include substantially spherical shape, cubic shape, cylindrical shape, prismatic shape, conical shape, pyramidal shape, flake shape, foil shape and dendritic shape. Etc., but a substantially spherical shape or a cubic shape is preferable.
　本発明の実施形態の導電性接着剤組成物において、繰り返し温度変化を受けた場合の被接着材料の剥離を高い水準で防止するために、熱可塑性樹脂の粒子（Ｂ）の含有量は導電性接着剤組成物の全体量に対して０．１質量％以上であることが好ましく、０．５質量％以上であることがより好ましく、１質量％以上であることがさらに好ましく、２質量％以上であることが特に好ましい。 In the conductive adhesive composition according to the embodiment of the present invention, the content of the thermoplastic resin particles (B) is set to be high in order to prevent peeling of the adherend material when subjected to repeated temperature changes at a high level. It is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, further preferably 1% by mass or more, and 2% by mass or more based on the total amount of the adhesive composition. Is particularly preferable.
　また、熱可塑性樹脂の粒子（Ｂ）を過剰に含有することによって導電性接着剤硬化物の熱伝導率が低下することを防止するため、熱可塑性樹脂の粒子（Ｂ）の含有量は導電性接着剤組成物の全体量に対して１０質量％以下であることが好ましく、７質量％以下であることがより好ましく、５質量％以下であることがさらに好ましい。 Further, in order to prevent the thermal conductivity of the conductive adhesive cured product from being lowered by excessively containing the thermoplastic resin particles (B), the content of the thermoplastic resin particles (B) is set to be conductive. It is preferably 10% by mass or less, more preferably 7% by mass or less, and further preferably 5% by mass or less based on the total amount of the adhesive composition.
　［その他の成分］
　＜バインダ樹脂＞
　本発明の実施形態の導電性接着剤組成物において、導電性フィラー（Ａ）、及び熱可塑性樹脂の粒子（Ｂ）は、バインダ樹脂中に分散されてもよい。バインダ樹脂は特に限定されないが、例えば、エポキシ樹脂、フェノール樹脂、ウレタン樹脂、アクリル樹脂、シリコーン樹脂又はポリイミド樹脂等を用いることができ、これらを単独で用いても、複数種類組み合わせて用いてもよい。作業性の観点から本発明の実施形態におけるバインダ樹脂は熱硬化性樹脂であることが好ましく、エポキシ樹脂であることが特に好ましい。 [Other ingredients]
<Binder resin>
In the conductive adhesive composition of the embodiment of the present invention, the conductive filler (A) and the thermoplastic resin particles (B) may be dispersed in the binder resin. The binder resin is not particularly limited, but for example, an epoxy resin, a phenol resin, a urethane resin, an acrylic resin, a silicone resin, a polyimide resin, or the like can be used, and these may be used alone or in combination of two or more kinds. .. From the viewpoint of workability, the binder resin in the embodiment of the present invention is preferably a thermosetting resin, and particularly preferably an epoxy resin.
　バインダ樹脂の含有量は、導電性接着剤組成物の全体量に対して１０質量％以下であることが好ましく、８質量％以下であることがより好ましく、６質量％以下であることがさらに好ましい。バインダ樹脂の含有量が１０質量％以下であると、導電性フィラーのネッキングによるネットワークが形成され易く、安定した導電性および熱伝導性が得られる。またバインダ樹脂を含有させる場合は、０．５質量％以上用いることが好ましい。 The content of the binder resin is preferably 10% by mass or less, more preferably 8% by mass or less, and further preferably 6% by mass or less with respect to the total amount of the conductive adhesive composition. .. When the content of the binder resin is 10% by mass or less, a network due to necking of the conductive filler is easily formed, and stable conductivity and thermal conductivity are obtained. When the binder resin is contained, it is preferably used in an amount of 0.5% by mass or more.
　＜硬化剤＞
　また、本発明の実施形態の導電性接着剤組成物は、上記成分のほかにも、例えば、硬化剤を含有していてもよい。硬化剤としては、例えば、三級アミン、アルキル尿素、イミダゾール等のアミン系硬化剤や、フェノール系硬化剤等が挙げられる。 <Curing agent>
Further, the conductive adhesive composition of the embodiment of the present invention may contain, for example, a curing agent in addition to the above components. Examples of the curing agent include amine-based curing agents such as tertiary amine, alkylurea, and imidazole, and phenol-based curing agents.
　硬化剤の含有量は導電性接着剤組成物の全体量に対して２質量％以下であることが好ましい。そうすることで未硬化の硬化剤が残りにくくなり、被接着材料との密着性が良好となる為である。 The content of the curing agent is preferably 2% by mass or less based on the total amount of the conductive adhesive composition. By doing so, the uncured curing agent is less likely to remain, and the adhesion with the adherend material becomes good.
　＜硬化促進剤＞
　本発明の実施形態の導電性接着剤組成物には硬化促進剤を配合することもできる。硬化促進剤としては、例えば、２－フェニル－４，５－ジヒドロキシメチルイミダゾール、２－フェニル－４―メチル－５－ヒドロキシメチルイミダゾール、２―メチル－４－メチルイミダゾール、１－シアノ－２－エチル－４－メチルイミダゾール等のイミダゾール類、第３級アミン類、トリフェニルフォスフィン類、尿素系化合物、フェノール類、アルコール類、カルボン酸類等が例示される。硬化促進剤は１種類だけ使用しても２種類以上を併用してもよい。 <Curing accelerator>
A curing accelerator may be added to the conductive adhesive composition according to the embodiment of the present invention. Examples of the curing accelerator include 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-methyl-4-methylimidazole, 1-cyano-2-ethyl. Examples thereof include imidazoles such as -4-methylimidazole, tertiary amines, triphenylphosphines, urea compounds, phenols, alcohols, carboxylic acids and the like. The curing accelerator may be used alone or in combination of two or more.
　硬化促進剤の配合量は限定されるものではなく適宜決定すればよいが、使用する場合は一般には、本発明の実施形態の導電性接着剤組成物の全体量に対して０．５質量％以下である。 The compounding amount of the curing accelerator is not limited and may be appropriately determined, but when used, it is generally 0.5% by mass with respect to the total amount of the conductive adhesive composition of the embodiment of the present invention. It is as follows.
　＜溶剤＞
　本発明の実施形態の導電性接着剤組成物には、さらに導電性接着剤組成物をペースト状にするために溶剤を含んでいてもよい。溶剤を含む場合は、ペースト中において熱可塑性樹脂の粒子（Ｂ）の形状を維持するために、これを溶解しない性質の溶剤を用いる。その他は特に限定されないが、導電性接着剤組成物の硬化の際に溶剤が揮発しやすいことから沸点３５０℃以下のものが好ましく、沸点３００℃以下のものがより好ましい。具体的にはアセテート、エーテル、炭化水素等が挙げられ、より具体的には、ジブチルカルビトール、ブチルカルビトールアセテート等が好ましく用いられる。 <Solvent>
The conductive adhesive composition of the embodiment of the present invention may further contain a solvent in order to make the conductive adhesive composition into a paste form. When a solvent is included, a solvent having a property of not dissolving the thermoplastic resin particles (B) is used in order to maintain the shape of the thermoplastic resin particles (B) in the paste. Others are not particularly limited, but those having a boiling point of 350° C. or less are preferable, and those having a boiling point of 300° C. or less are more preferable because the solvent is easily volatilized during curing of the conductive adhesive composition. Specific examples thereof include acetate, ether and hydrocarbon, and more specifically, dibutyl carbitol, butyl carbitol acetate and the like are preferably used.
　溶剤の含有率は、導電性接着剤組成物に対して通常１５質量％以下であり、作業性の観点から好ましくは１０質量％以下である。 The content of the solvent is usually 15% by mass or less based on the conductive adhesive composition, and preferably 10% by mass or less from the viewpoint of workability.
　本発明の実施形態の導電性接着剤組成物には、上記成分の他にも、酸化防止剤、紫外線吸収剤、粘着付与剤、粘性調整剤、分散剤、カップリング剤、強靭性付与剤、エラストマー等を、本発明の実施形態の効果を損なわない範囲で適宜配合することができる。 In the conductive adhesive composition of the embodiment of the present invention, in addition to the above components, an antioxidant, an ultraviolet absorber, a tackifier, a viscosity modifier, a dispersant, a coupling agent, a toughening agent, An elastomer or the like can be appropriately blended within a range that does not impair the effects of the embodiment of the present invention.
　本発明の実施形態の導電性接着剤組成物は、上記の（Ａ）及び（Ｂ）並びにその他の成分を任意の順序で混合、撹拌することにより得ることができる。分散方法としては、例えば、二本ロール、三本ロール、サンドミル、ロールミル、ボールミル、コロイドミル、ジェットミル、ビーズミル、ニーダー、ホモジナイザー、及びプロペラレスミキサー等の方式を採用することができる。 The conductive adhesive composition according to the embodiment of the present invention can be obtained by mixing and stirring the above components (A) and (B) and other components in any order. As the dispersion method, for example, a method such as a two-roll, a three-roll, a sand mill, a roll mill, a ball mill, a colloid mill, a jet mill, a bead mill, a kneader, a homogenizer, and a propellerless mixer can be adopted.
　本発明の実施形態の導電性接着剤硬化物は、上記導電性接着剤組成物を熱処理して硬化させることにより得られる。 The electrically conductive adhesive cured product of the embodiment of the present invention is obtained by heat treating the electrically conductive adhesive composition to cure it.
　本発明の実施形態の導電性接着剤組成物を硬化させる際の加熱の温度は特に限定はされないが、導電性フィラー（Ａ）同士、及び、被接着材料と導電性フィラー（Ａ）との間に、互いに点接触した近接状態を形成させ、接着部としての形状を安定させるために１５０℃以上であることが好ましく、１８０℃以上であることがより好ましく、２００℃以上であることがさらに好ましい。 The temperature of heating when curing the conductive adhesive composition of the embodiment of the present invention is not particularly limited, but between the conductive fillers (A), and between the adherend material and the conductive filler (A). In order to form a close contact with each other in point contact with each other and stabilize the shape of the adhesive portion, the temperature is preferably 150° C. or higher, more preferably 180° C. or higher, and further preferably 200° C. or higher. ..
　また、導電性フィラー（Ａ）同士の結合が過度に進行し導電性フィラー（Ａ）間のネッキングが生じて強固に結合し、硬すぎる状態となることを避けるために３００℃以下であることが好ましく、２７５℃以下であることがより好ましく、２５０℃以下であることがさらに好ましい。 Further, the temperature is 300° C. or lower in order to prevent the conductive fillers (A) from excessively adhering to each other and causing necking between the conductive fillers (A) to strongly bond with each other and become too hard. The temperature is preferably 275° C. or lower, more preferably 250° C. or lower.
　また、上記加熱の時間は、導電性フィラー（Ａ）の焼結が十分に進行するような時間であれば特に限定はされないが、通常は０．５～３時間である。 The heating time is not particularly limited as long as the conductive filler (A) is sufficiently sintered, but is usually 0.5 to 3 hours.
　上記加熱は、空気中でおこなってもよく、Ｎ２などの不活性ガス中でおこなってもよい。空気中で加熱すると、導電性フィラー（Ａ）の表面のコーティング剤の除去が進みやすいため、焼結を行いやすいが、導電性フィラー（Ａ）が酸化されやすいため、得られる導電性接着剤硬化物の導電性や熱伝導率が損なわれるおそれがある。また、空気中で加熱すると、酸化しやすい被着体（例えばＣｕ基板など）を用いた場合に被着体が酸化して接合が阻害されたり、他にも酸化されやすい周辺部材が酸化されて劣化したりするおそれもある。 The heating may be performed in air or in an inert gas such as N 2 . When heated in the air, the coating agent on the surface of the conductive filler (A) is easily removed, so that it is easy to sinter, but since the conductive filler (A) is easily oxidized, the obtained conductive adhesive is cured. There is a risk that the electrical conductivity and thermal conductivity of the object will be impaired. Further, when heated in air, when an adherend that easily oxidizes (for example, a Cu substrate) is used, the adherend is oxidized and the bonding is hindered, and other peripheral members that are easily oxidized are oxidized. There is also a risk of deterioration.
　したがって、上記のような問題の発生を回避するためには、Ｎ２などの不活性ガス中で加熱を行うことが好ましい。また、不活性ガス中で加熱を行う場合は、金属粒子（ａ１）及び銀粒子（ａ２）のコーティング剤として先述の適切なものを採用することが好ましい。 Therefore, in order to avoid the occurrence of the above problems, it is preferable to perform heating in an inert gas such as N 2 . When heating is performed in an inert gas, it is preferable to employ the above-mentioned appropriate coating agent for the metal particles (a1) and the silver particles (a2).
　半導体素子等の被着体から発生した熱を効率よく逃がすためには、導電性接着剤硬化物は薄いことが好ましい。具体的には、導電性接着剤硬化物の厚みは５０μｍ以下が好ましく、４０μｍ以下がより好ましく、３０μｍ以下が更に好ましい。 In order to efficiently release the heat generated from the adherend such as a semiconductor element, it is preferable that the conductive adhesive cured product is thin. Specifically, the thickness of the cured product of the conductive adhesive is preferably 50 μm or less, more preferably 40 μm or less, still more preferably 30 μm or less.
　一方、基板等の被着体の熱膨張差から発生する内部応力を接着剤層厚み方向で担うため導電性接着剤硬化物は厚い方が望ましい。具体的には、導電性接着剤硬化物の厚みは５μｍ以上が好ましく、１０μｍ以上がより好ましく、２０μｍ以上が更に好ましい。 On the other hand, it is desirable that the cured conductive adhesive be thicker, because it takes on the internal stress generated by the difference in thermal expansion of adherends such as substrates in the thickness direction of the adhesive layer. Specifically, the thickness of the cured product of the conductive adhesive is preferably 5 μm or more, more preferably 10 μm or more, still more preferably 20 μm or more.
　本発明の実施形態の導電性接着剤硬化物の熱伝導率は、被接着材料の放熱性を確保するために、２０Ｗ／ｍ・Ｋ以上であることが好ましく、３５Ｗ／ｍ・Ｋ以上であることがより好ましく、５０Ｗ／ｍ・Ｋ以上であることがさらに好ましい。なお、導電性接着剤硬化物の熱伝導率は、実施例の欄において後述する方法を用いて算出することができる。 The thermal conductivity of the conductive adhesive cured product of the embodiment of the present invention is preferably 20 W/m·K or more, and is 35 W/m·K or more in order to secure the heat dissipation of the adherend material. More preferably, it is more preferably 50 W/m·K or more. The thermal conductivity of the conductive adhesive cured product can be calculated by the method described later in the Example section.
　本発明の実施形態の導電性接着剤組成物を用いて被接着材料を接着した場合に、繰り返し温度変化を受けた場合にも被接着材料の剥離が生じにくくなっていることを評価する方法としては、種々の方法が挙げられるが、例えば、実施例の欄において後述する方法で冷熱サイクル試験を行い、試験後の剥離面積の割合を実施例の欄において後述する方法で測定する方法が挙げられる。当該方法で測定した剥離面積の割合は１５％以下であることが好ましく、１０％以下であることがより好ましく、５％以下であることがさらに好ましい。 When a material to be bonded is bonded using the conductive adhesive composition of the embodiment of the present invention, as a method for evaluating that peeling of the material to be bonded is less likely to occur even when subjected to repeated temperature changes Examples include various methods, for example, a method of performing a thermal cycle test by the method described below in the Example section, and measuring the ratio of the peeled area after the test by the method described below in the Example section. .. The ratio of the peeled area measured by the method is preferably 15% or less, more preferably 10% or less, and further preferably 5% or less.
　本発明の実施形態の導電性接着剤組成物は、電子機器における部品の接着に用いることができる。 The conductive adhesive composition according to the embodiment of the present invention can be used for bonding components in electronic devices.
　以下、実施例により本発明をさらに具体的に説明するが、本発明はこれらの実施例により何ら限定されるものではない。 Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to these Examples.
　Ａ．導電性接着剤組成物の調製
　表１～３に記載された各材料を三本ロールにて混練し、表１～３に示す組成の導電性接着剤組成物を調製した（各材料の数値は導電性接着剤組成物の総質量に対する質量％を表す）。使用した材料は下記の通りである。なお、混練の順番は、金属粒子（ａ１）、銀粒子（ａ２）、熱可塑性樹脂の粒子（Ｂ）、バインダ樹脂、硬化剤、硬化促進剤、溶剤の順である。 A. Preparation of Conductive Adhesive Composition Each material shown in Tables 1 to 3 was kneaded with a triple roll to prepare a conductive adhesive composition having a composition shown in Tables 1 to 3 (numerical values of each material are It represents mass% based on the total mass of the conductive adhesive composition). The materials used are as follows. The order of kneading is metal particles (a1), silver particles (a2), thermoplastic resin particles (B), binder resin, curing agent, curing accelerator, and solvent.
　［導電性フィラー（Ａ）］
　＜金属粒子（ａ１）＞
・銀粒子（１）：フレーク状、平均粒子径ｄ５０：５．５μｍ、タップ密度：７．０ｇ／ｃｍ３、田中貴金属工業社製
・銀粒子（２）：フレーク状、平均粒子径ｄ５０：４μｍ、タップ密度：６．７ｇ／ｃｍ３、田中貴金属工業社製
・銀粒子（３）：球状、平均粒子径ｄ５０：０．８μｍ、タップ密度：５．５ｇ／ｃｍ３、田中貴金属工業社製
・銅粒子：球状、平均粒子径ｄ５０：５μｍ、タップ密度：５．０ｇ／ｃｍ３、三井金属鉱業社製 [Conductive filler (A)]
<Metal particles (a1)>
-Silver particles (1): flakes, average particle diameter d50: 5.5 μm, tap density: 7.0 g/cm 3 , manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.-Silver particles (2): flakes, average particle diameter d50: 4 μm , Tap density: 6.7 g/cm 3 , manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.-Silver particles (3): spherical, average particle diameter d50: 0.8 μm, tap density: 5.5 g/cm 3 , manufactured by Tanaka Kikinzoku Kogyo Co., Ltd. Copper particles: spherical, average particle diameter d50: 5 μm, tap density: 5.0 g/cm 3 , manufactured by Mitsui Mining & Smelting Co., Ltd.
　＜銀粒子（ａ２）＞
・銀粒子（４）：球状、平均粒子径ｄ５０：０．０９μｍ、田中貴金属工業社製、コーティング剤としてカルボキシル基を有する高分子分散剤（ビッグケミー製、「ディスパービック１９０」、親水性ユニットであるポリエチレンオキサイド鎖と疎水性ユニットであるアルキル基とを有する両親媒性分散剤、溶媒：水、不揮発成分４０％、酸価１０ｍｇＫＯＨ／ｇ、アミン価０）
・銀粒子（５）：球状、平均粒子径ｄ５０：０．１６μｍ、田中貴金属工業社製、コーティング剤としてオレイン酸
・銀粒子（６）：球状、平均粒子径ｄ５０：０．１０μｍ、田中貴金属工業社製、コーティング剤としてドデシルアミン <Silver particles (a2)>
Silver particles (4): spherical, average particle diameter d50: 0.09 μm, manufactured by Tanaka Kikinzoku Kogyo Co., Ltd., polymer dispersant having a carboxyl group as a coating agent (manufactured by Big Chemie, “Disperbic 190”, hydrophilic unit). An amphipathic dispersant having a polyethylene oxide chain and an alkyl group which is a hydrophobic unit, solvent: water, nonvolatile component 40%, acid value 10 mgKOH/g, amine value 0)
Silver particles (5): spherical, average particle diameter d50: 0.16 μm, manufactured by Tanaka Kikinzoku Kogyo Co., Ltd., as coating agent oleic acid/silver particles (6): spherical, average particle diameter d50: 0.10 μm, Tanaka Kikinzoku Kogyo Made by Dodecylamine as coating agent
　［熱可塑性樹脂の粒子（Ｂ）］
・熱可塑性樹脂粒子（１）：「ＳＰ－５００」（商品名）、東レ社製、ナイロン１２製、平均粒子径ｄ５０：５μｍ、球状、融点：１６５～１７１℃
・熱可塑性樹脂粒子（２）：「ＳＰ－１０」（商品名）、東レ社製、ナイロン１２製、平均粒子径ｄ５０：１０μｍ、球状、融点：１６５～１７１℃
・熱可塑性樹脂粒子（３）：「ＰＭ－２００」（商品名）、三井化学社製、ポリエチレン製、平均粒子径ｄ５０：１０μｍ、球状、融点：１３６℃
・熱可塑性樹脂粒子（４）：東レ社製「ＳＰ－５００」（商品名）を分級して得られた粒子、ナイロン１２製、分級後の平均粒子径ｄ５０：３μｍ（分級前のｄ５０は５μｍ）、球状、融点：１６５～１７１℃
・熱可塑性樹脂粒子（５）：東レ社製「ＳＰ－１０」（商品名）を分級して得られた粒子、ナイロン１２製、分級後の平均粒子径ｄ５０：１５μｍ（分級前のｄ５０は１０μｍ）、球状、融点：１６５～１７１℃
・熱可塑性樹脂粒子（６）：「Ｏｒａｇａｓｏｌ３５０１ＥＸＤ」（商品名）、アルケマ社製、ナイロン１２およびナイロン６の共重合体製、平均粒子径ｄ５０：１０μｍ、球状、融点：１４２℃
・熱可塑性樹脂粒子（７）：「ＴＲ-１」（商品名）、東レ社製、ナイロン６製、平均粒子径ｄ５０：１３μｍ、球状、融点：２１５℃ [Thermoplastic resin particles (B)]
-Thermoplastic resin particles (1): "SP-500" (trade name), manufactured by Toray Industries, Inc., made of nylon 12, average particle diameter d50: 5 μm, spherical, melting point: 165 to 171°C
-Thermoplastic resin particles (2): "SP-10" (trade name), Toray, nylon 12, average particle diameter d50:10 μm, spherical, melting point: 165 to 171°C
-Thermoplastic resin particles (3): "PM-200" (trade name), manufactured by Mitsui Chemicals, Inc., polyethylene, average particle diameter d50:10 µm, spherical, melting point: 136°C
-Thermoplastic resin particles (4): particles obtained by classifying "SP-500" (trade name) manufactured by Toray Industries, Inc., made of nylon 12, average particle size d50 after classification d3: 3 μm (d50 before classification is 5 μm) ), spherical, melting point: 165-171°C
-Thermoplastic resin particles (5): particles obtained by classifying "SP-10" (trade name) manufactured by Toray Industries, Inc., made of nylon 12, average particle size after classification d50: 15 μm (d50 before classification is 10 μm) ), spherical, melting point: 165-171°C
-Thermoplastic resin particles (6): "Oragasol 3501EXD" (trade name), manufactured by Arkema, made of a copolymer of nylon 12 and nylon 6, average particle diameter d50:10 μm, spherical, melting point: 142°C.
-Thermoplastic resin particles (7): "TR-1" (trade name), manufactured by Toray, nylon 6, average particle diameter d50: 13 µm, spherical, melting point: 215°C
　［バインダ樹脂・硬化剤・硬化促進剤・溶剤］
・エポキシ樹脂（１）：「ＥＰＩＣＬＯＮ　８３０－Ｓ」（商品名）、大日本インキ化学工業社製、室温で液状、エポキシ当量：１６９ｇ／ｅｑ
・エポキシ樹脂（２）：「ＥＲＩＳＹＳ　ＧＥ－２１」（商品名）、ＣＶＣ社製、室温で液状、エポキシ当量：１２５ｇ／ｅｑ
・硬化剤：フェノール系硬化剤（ＭＥＨ８０００Ｈ、明和化成社製）
・硬化剤促進：２－フェニル－４，５－ジヒドロキシメチルイミダゾール（２ＰＨＺ、四国化成社製）
・溶剤（１）：ジブチルカルビトール（東京化成工業社製）
・溶剤（２）：ブチルカルビトールアセテート（東京化成工業社製） [Binder resin, curing agent, curing accelerator, solvent]
Epoxy resin (1): "EPICLON 830-S" (trade name), manufactured by Dainippon Ink and Chemicals, Inc., liquid at room temperature, epoxy equivalent: 169 g/eq
Epoxy resin (2): "ERISYS GE-21" (trade name), manufactured by CVC, liquid at room temperature, epoxy equivalent: 125 g/eq
-Curing agent: Phenolic curing agent (MEH8000H, manufactured by Meiwa Kasei Co., Ltd.)
・Promoting curing agent: 2-phenyl-4,5-dihydroxymethylimidazole (2PHZ, manufactured by Shikoku Kasei)
・Solvent (1): Dibutyl carbitol (Tokyo Chemical Industry Co., Ltd.)
・Solvent (2): Butyl carbitol acetate (manufactured by Tokyo Chemical Industry Co., Ltd.)
　Ｂ．物性評価
　得られた導電性接着剤組成物を１０ｍｍ×１０ｍｍの銀メッキした銅リードフレームに塗布し、塗布面に５ｍｍ×５ｍｍの銀スパッタリングシリコンチップを戴置後、窒素雰囲気下、２５０℃で６０分加熱し、銀メッキした銅リードフレームと銀スパッタリングしたシリコンチップが導電性接着剤硬化物により接合された金属接合体（以下、単に「金属接合体」ともいう）を作製した。得られた金属接合体について、以下に示す方法で物性評価を行った。 B. Evaluation of Physical Properties The obtained conductive adhesive composition was applied to a 10 mm×10 mm silver-plated copper lead frame, and a 5 mm×5 mm silver-sputtering silicon chip was placed on the coated surface, and then at 60° C. at 250° C. in a nitrogen atmosphere. After heating for minutes, a silver-plated copper lead frame and a silver-sputtered silicon chip were joined by a conductive adhesive cured product (hereinafter, also simply referred to as “metal joined body”). The physical properties of the obtained metal bonded body were evaluated by the methods described below.
　＜熱伝導率＞
　得られた金属接合体の熱伝導率を表１～３に示す。
　熱伝導率λ（Ｗ／ｍ・Ｋ）は、レーザーフラッシュ法熱定数測定装置　（「ＴＣ－７０００」（商品名）、ＵＬＶＡＣ－ＲＩＫＯ社製）を用いてＡＳＴＭ－Ｅ１４６１に準拠して熱拡散ａを測定し、ピクノメーター法により室温での比重ｄを算出し、また、示差走査熱量測定装置（「ＤＳＣ７０２０」（商品名）、セイコー電子工業社製）を用いてＪＩＳ－Ｋ７１２３　２０１２に準拠して室温での比熱Ｃｐを測定して、関係式λ＝ａ×ｄ×Ｃｐにより算出した。 <Thermal conductivity>
The thermal conductivity of the obtained metal bonded body is shown in Tables 1 to 3.
The thermal conductivity λ (W/m·K) was measured using a laser flash method thermal constant measuring device (“TC-7000” (trade name), manufactured by ULVAC-RIKO) in accordance with ASTM-E1461. Was measured, and the specific gravity d at room temperature was calculated by a pycnometer method. Further, a differential scanning calorimeter (“DSC7020” (trade name), manufactured by Seiko Instruments Inc.) was used in accordance with JIS-K7123 2012. The specific heat Cp at room temperature was measured and calculated by the relational expression λ=a×d×Cp.
　＜剥離試験１＞
　また、得られた金属接合体を用いて冷熱サイクル試験を行い、剥離面積を測定した。この試験では、基板を－５０℃に３０分間保持した後に１５０℃に３０分間保持する操作を１サイクルとして２０００サイクル繰返し、試験後のシリコンチップの剥離面積の割合を測定した。結果を表１～３に示す。
　なお、剥離面積の割合は、２０００サイクル後の超音波映像・検査装置「Ｆｉｎｅ　ＳＡＴ」（商品名）で得られた剥離状態の画像を二値化ソフト「ｉｍａｇｅ　Ｊ」で濃淡を白と黒の二階調に画像変換し、以下の関係式で求めた。
　剥離面積の割合（％）＝剥離面積（黒色画素数）÷チップ面積（黒色画素数＋白色画素数）×１００ <Peeling test 1>
Further, a cooling/heating cycle test was performed using the obtained metal bonded body, and the peeled area was measured. In this test, the operation of holding the substrate at −50° C. for 30 minutes and then at 150° C. for 30 minutes was repeated as 2000 cycles, and the ratio of the peeled area of the silicon chip after the test was measured. The results are shown in Tables 1 to 3.
In addition, the ratio of the peeled area is the image of the peeled state obtained by the ultrasonic image/inspection device “Fine SAT” (trade name) after 2000 cycles, and the binarization software “image J” is used to change the shade between white and black. The image was converted into two gradations and calculated by the following relational expression.
Ratio of peeled area (%) = peeled area (black pixel number) / chip area (black pixel number + white pixel number) x 100
　＜剥離試験２＞
　冷却及び加熱のサイクル数を３０００サイクルとした点以外は剥離試験１と同様にして、剥離試験２を行った。結果を表１～３に示す。なお、表１～３の剥離試験２の欄の「‐」は、剥離試験２を行っていないことを意味する。 <Peeling test 2>
Peeling test 2 was performed in the same manner as peeling test 1 except that the number of cooling and heating cycles was 3000. The results are shown in Tables 1 to 3. In addition, "-" in the column of the peeling test 2 in Tables 1 to 3 means that the peeling test 2 was not performed.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　表１～３に示すように、実施例の導電性接着剤組成物で得られた金属接合体は、比較例の導電性接着剤組成物で得られた金属接合体と比べて冷熱サイクル試験後の剥離面積が少なかった。また、熱伝導率も良好な値であった。 As shown in Tables 1 to 3, the metal bonded bodies obtained with the conductive adhesive compositions of Examples were compared with the metal bonded bodies obtained with the conductive adhesive compositions of Comparative Examples after the thermal cycling test. The peeled area was small. The thermal conductivity was also a good value.
　この結果から、本発明の実施形態の導電性接着剤組成物によれば、熱伝導性に優れ、さらに繰り返し温度変化を受けた場合にも被接着材料の剥離が生じにくい接着を達成できることが確認された。 From these results, it is confirmed that the conductive adhesive composition according to the embodiment of the present invention can achieve an adhesive having excellent thermal conductivity and in which peeling of the adherend material is less likely to occur even when subjected to repeated temperature changes. Was done.
　本発明を特定の態様を用いて詳細に説明したが、本発明の意図と範囲を離れることなく様々な変更及び変形が可能であることは、当業者にとって明らかである。なお本出願は、２０１９年１月１０日付で出願された日本特許出願（特願２０１９－００２８２２）に基づいており、その全体が引用により援用される。 Although the present invention has been described in detail using specific modes, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on the Japanese patent application (Japanese Patent Application No. 2019-002822) filed on January 10, 2019, which is incorporated by reference in its entirety.

Claims (7)

  1. 　平均粒子径０．５～１０μｍの金属粒子（ａ１）と平均粒子径１０～２００ｎｍの銀粒子（ａ２）とを含む導電性フィラー（Ａ）と、
    　平均粒子径２～１４μｍの熱可塑性樹脂の粒子（Ｂ）と、を含有し、
    　前記熱可塑性樹脂の融点が、１３０～２５０℃である導電性接着剤組成物。     A conductive filler (A) containing metal particles (a1) having an average particle diameter of 0.5 to 10 μm and silver particles (a2) having an average particle diameter of 10 to 200 nm,
    Thermoplastic resin particles (B) having an average particle diameter of 2 to 14 μm,
    A conductive adhesive composition in which the melting point of the thermoplastic resin is 130 to 250°C.
  2. 　前記金属粒子（ａ１）の主成分が銀である請求項１に記載の導電性接着剤組成物。 The conductive adhesive composition according to claim 1, wherein the main component of the metal particles (a1) is silver.
  3. 　前記導電性接着剤組成物の全体量に対して、前記金属粒子（ａ１）を３５～８５質量％、前記銀粒子（ａ２）を５～５０質量％の範囲で含有する請求項１または２に記載の導電性接着剤組成物。 The metal particles (a1) are contained in an amount of 35 to 85% by mass and the silver particles (a2) are included in an amount of 5 to 50% by mass based on the total amount of the conductive adhesive composition. The electrically conductive adhesive composition described.
  4. 　前記金属粒子（ａ１）と前記銀粒子（ａ２）との含有比率が、質量比で９５：５～４０：６０の範囲である請求項１～３のいずれか１項に記載の導電性接着剤組成物。 The conductive adhesive according to any one of claims 1 to 3, wherein a content ratio of the metal particles (a1) and the silver particles (a2) is in a range of 95:5 to 40:60 by mass ratio. Composition.
  5. 　前記導電性接着剤組成物の全体量に対して、前記熱可塑性樹脂の粒子（Ｂ）を０．１～１０質量％の範囲で含有する請求項１～４のいずれか１項に記載の導電性接着剤組成物。 The conductive material according to any one of claims 1 to 4, wherein the thermoplastic resin particles (B) are contained in the range of 0.1 to 10 mass% with respect to the total amount of the conductive adhesive composition. Adhesive composition.
  6. 　請求項１～５のいずれか１項に記載の導電性接着剤組成物を硬化した、導電性接着剤硬化物。 A conductive adhesive cured product obtained by curing the conductive adhesive composition according to any one of claims 1 to 5.
  7. 　請求項１～５のいずれか１項に記載の導電性接着剤組成物を部品の接着に使用した電子機器。 Electronic equipment using the conductive adhesive composition according to any one of claims 1 to 5 for bonding parts.
PCT/JP2019/051028 2019-01-10 2019-12-25 Conductive adhesive agent composition WO2020145170A1 (en)

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