Coated particle, resin composition and connection structure

Abstract

To provide a coated particle that can reduce connection resistance when electrically connecting electrodes, and can enhance conduction reliability during extended use at high temperatures and high humidity.SOLUTION: A coated particle comprises a conductive particle, and an organic compound containing fluorine. The conductive particle comprises a base particle, and a conduction part disposed on the surface of the base particle. The conduction part comprises nickel. The organic compound containing fluorine coats at least a part of the surface of the conduction part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a coated particle using a conductive particle. The present invention also relates to a resin composition and a connection structure using the coated particle. [Background technology]

[0002] Anisotropic conductive materials, such as anisotropic conductive pastes and anisotropic conductive films, are widely known, in which conductive particles are dispersed in a binder resin.

[0003] The anisotropic conductive material is used to obtain various connection structures. Examples of connections using the anisotropic conductive material include connections between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)), between a semiconductor chip and a flexible printed circuit board (COF (Chip on Film)), between a semiconductor chip and a glass substrate (COG (Chip on Glass)), and between a flexible printed circuit board and a glass epoxy substrate (FOB (Film on Board)).

[0004] Furthermore, as the conductive particles, conductive particles in which a base particle and a conductive layer are disposed on the surface of the base particle may be used.

[0005] The following Patent Document 1 discloses a conductive particle comprising a nickel layer and a gold layer formed on the nickel layer. The average thickness of the gold layer is 300 Å or less. In this conductive particle, the gold layer is the outermost layer. In addition, in this conductive particle, the elemental composition ratio of nickel to gold (Ni / Au) on the surface of the conductive particle by X-ray photoelectron spectroscopy analysis is 0.4 or less.

[0006] The following Patent Document 2 discloses a conductive particle including a core particle, a Ni plating layer, a precious metal plating layer, and an anti-rust film. The Ni plating layer covers the core particle. The precious metal plating layer covers at least a part of the Ni plating layer. The precious metal plating layer contains at least one of Au and Pd. The anti-rust film covers at least one of the Ni plating layer and the precious metal plating layer. The anti-rust film contains an organic compound. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2009-102731 A [Patent Document 2] JP 2013-20721 A Summary of the Invention [Problem to be solved by the invention]

[0008] In recent years, in conductive materials containing conductive particles, the particle size of conductive particles has been reduced due to finer pitches in wiring and connectors in printed wiring boards and the like.

[0009] However, conductive particles with a small particle size cause large distortion in the conductive layer, and therefore, when conductive particles are used to electrically connect electrodes, stress is concentrated in the conductive layer, causing cracks and the like in the conductive layer, making it difficult to reduce the connection resistance.

[0010] In addition, when conductive particles that have been exposed to a high-temperature, high-humidity environment for a long period of time are used, or when a connection structure using conductive particles is exposed to a high-temperature, high-humidity environment for a long period of time, there is a problem that the connection resistance is likely to increase (the conductivity reliability is likely to decrease).

[0011] An object of the present invention is to provide coated particles that can reduce connection resistance when electrically connecting electrodes and can increase electrical conductivity reliability when used for a long period of time under high temperature and high humidity conditions. Another object of the present invention is to provide a resin composition and a connection structure using the coated particles. [Means for solving the problem]

[0012] According to a broad aspect of the present invention, there is provided a coated particle comprising a conductive particle and an organic compound containing fluorine, the conductive particle having a base particle and a conductive portion disposed on a surface of the base particle, the conductive portion containing nickel, and the organic compound containing fluorine coating at least a portion of the surface of the conductive portion.

[0013] In a specific aspect of the coated particles according to the present invention, the fluorine-containing organic compound is polyvinylidene fluoride, a perfluoroalkyl compound, or a polyfluoroalkyl compound.

[0014] In a specific aspect of the coated particles according to the present invention, in a TOF-SIMS analysis, the ratio of the fluorine ion intensity on the surface of the coated particles to the sum of the ion intensities of all negative ions is 0.0001 or more.

[0015] In a specific aspect of the coated particle according to the present invention, the outer surface portion of the conductive portion contains nickel.

[0016] In a specific aspect of the coated particles according to the present invention, the fluorine-containing organic compound has a phosphate group.

[0017] In a specific aspect of the coated particles according to the present invention, the coated particles have a particle size of 1.0 μm or more and 4.0 μm or less.

[0018] In a specific aspect of the coated particle according to the present invention, the coated particle further includes a plurality of insulating particles, the plurality of insulating particles being disposed on a surface of the conductive particle.

[0019] In a specific aspect of the coated particle according to the present invention, no insulating particles are disposed on the surface of the conductive particle.

[0020] According to a broad aspect of the present invention, there is provided a resin composition comprising the above-described coated particles and a binder resin.

[0021] According to a broad aspect of the present invention, there is provided a connection structure comprising a first connection target member having a first electrode on its surface, a second connection target member having a second electrode on its surface, and a connection portion connecting the first connection target member and the second connection target member, wherein a material of the connection portion contains the coated particles described above, and the first electrode and the second electrode are electrically connected by the conductive particles. Effect of the Invention

[0022] The coated particles according to the present invention include conductive particles and an organic compound containing fluorine. In the coated particles according to the present invention, the conductive particles include a base particle and a conductive portion disposed on the surface of the base particle. In the coated particles according to the present invention, the conductive portion includes nickel. In the coated particles according to the present invention, the organic compound containing fluorine coats at least a portion of the surface of the conductive portion. Since the coated particles according to the present invention have the above configuration, when the conductive particles according to the present invention are used to electrically connect electrodes, the connection resistance can be reduced, and the electrical connection reliability can be increased when the conductive particles are used for a long period of time under high temperature and high humidity. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a cross-sectional view showing a covered particle according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view showing a covered particle according to a second embodiment of the present invention. [Diagram 3] FIG. 3 is a cross-sectional view showing a covered particle according to a third embodiment of the present invention. [Figure 4]FIG. 4 is a cross-sectional view showing a covered particle according to a fourth embodiment of the present invention. [Diagram 5] FIG. 5 is a cross-sectional view showing a covered particle according to a fifth embodiment of the present invention. [Figure 6] FIG. 6 is a cross-sectional view showing a covered particle according to a sixth embodiment of the present invention. [Figure 7] FIG. 7 is a cross-sectional view that illustrates a connection structure using the covered particles according to the first embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] The present invention will be described in detail below.

[0025] (Coated particles) The coated particle according to the present invention comprises a conductive particle and an organic compound containing fluorine. In the coated particle according to the present invention, the conductive particle has a base particle and a conductive portion disposed on the surface of the base particle. In the coated particle according to the present invention, the conductive portion contains nickel. In the coated particle according to the present invention, the organic compound containing fluorine coats at least a portion of the surface of the conductive portion.

[0026] Since the coated particles according to the present invention have the above-mentioned configuration, the initial connection resistance after conductive connection can be reduced, and the conductive reliability can be increased when used for a long period of time under high temperature and high humidity conditions.

[0027] Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. Note that different parts in Fig. 1 and the figures described later can be replaced with each other. Also, in Fig. 1 and the figures described later, for convenience of illustration, the size and thickness of each component may differ from the actual size and thickness.

[0028] FIG. 1 is a cross-sectional view showing a covered particle according to a first embodiment of the present invention.

[0029] 1 includes a conductive particle 2 and a fluorine-containing organic compound 3. In the coated particle 1, the conductive particle 2 includes a base particle 21 and a conductive portion 22 disposed on the surface of the base particle 21.

[0030] In the coated particle 1, the fluorine-containing organic compound 3 coats the surface of the conductive particle 2 (the surface of the conductive portion 22). In the coated particle 1, the fluorine-containing organic compound 3 is disposed on the surface of the conductive particle 2 (the surface of the conductive portion 22) and is in contact with the conductive particle 2 (the conductive portion 22).

[0031] The conductive portion 22 covers the surface of the base particle 21. In the conductive particle 2, the surface of the base particle 21 is covered with the conductive portion 22. The conductive particle 2 has the conductive portion 22 on the surface.

[0032] In the coated particle 1, the conductive portion 22 is a conductive layer. The conductive portion 22 is a single-layer conductive layer. In the conductive particle, the conductive portion may cover the entire surface of the base particle, or the conductive portion may cover only a portion of the surface of the base particle.

[0033] The coated particles 1 can be obtained, for example, by dipping conductive particles 2 before disposing the fluorine-containing organic compound 3 in a fluorine-containing organic compound dispersion liquid to form the fluorine-containing organic compound 3. The coated particles 1A and 1B described below can also be obtained in the same manner as the coated particles 1.

[0034] FIG. 2 is a cross-sectional view showing a covered particle according to a second embodiment of the present invention.

[0035] 2 includes a conductive particle 2A and a fluorine-containing organic compound 3A. In the coated particle 1A, the conductive particle 2A includes a base particle 21A and a conductive portion 22A disposed on the surface of the base particle 21A.

[0036] In the coated particle 1A, the fluorine-containing organic compound 3A coats the surface of the conductive particle 2A (the surface of the conductive portion 22A). In the coated particle 1A, the fluorine-containing organic compound 3A is disposed on the surface of the conductive particle 2A (the surface of the conductive portion 22A) and is in contact with the conductive particle 2A (the conductive portion 22A).

[0037] In the coated particle 1A, the conductive portion 22A is a two-layer conductive layer. The conductive portion 22A includes a first conductive portion 22AA and a second conductive portion 22AB. In the conductive portion 22A, the first conductive portion 22AA is laminated on the surface of the base particle 21A, and the second conductive portion 22AB is laminated on the surface of the first conductive portion 22AA.

[0038] The structure of the conductive part is different between the covered particle 1 and the covered particle 1A. The conductive part may be a single conductive layer or multiple conductive layers.

[0039] FIG. 3 is a cross-sectional view showing a covered particle according to a third embodiment of the present invention.

[0040] 3 includes a conductive particle 2B and a fluorine-containing organic compound 3B. In the coated particle 1B, the conductive particle 2B includes a base particle 21B, a conductive portion 22B disposed on the surface of the base particle 21B, and a plurality of core materials 23B disposed on the surface of the base particle 21B.

[0041] In the coated particle 1B, the fluorine-containing organic compound 3B coats the surface of the conductive particle 2B (the surface of the conductive portion 22B). In the coated particle 1B, the fluorine-containing organic compound 3B is disposed on the surface of the conductive particle 2B (the surface of the conductive portion 22B) and is in contact with the conductive particle 2B (the conductive portion 22B).

[0042] In the coated particle 1B, the conductive portion 22B coats the base particle 21B and the core material 23B. Since the conductive portion 22B coats the core material 23B, the coated particle 1B and the conductive particle 2B have a plurality of protrusions 2Ba on their surfaces. The surface of the conductive portion 22B is raised by the core material 23B, forming a plurality of protrusions 2Ba.

[0043] The difference between the coated particles 1 and the coated particles 1B is whether a core substance is used or not, and whether protrusions are present or not. The coated particles may or may not have protrusions on the surface.

[0044] FIG. 4 is a cross-sectional view showing a covered particle according to a fourth embodiment of the present invention.

[0045] The coated particle 1C shown in Fig. 4 includes a conductive particle 2C, a fluorine-containing organic compound 3C, and a plurality of insulating particles 4C. The coated particle 1C includes the conductive particle 2C, the fluorine-containing organic compound 3C, and further includes a plurality of insulating particles 4C. In the coated particle 1C, a plurality of insulating particles 4C are disposed on the surface of the conductive particle 2C. In the coated particle 1C, the conductive particle 2C includes a base particle 21C and a conductive portion 22C disposed on the surface of the base particle 21C.

[0046] In the coated particle 1C, the fluorine-containing organic compound 3C coats the surface of the conductive particle 2C (the surface of the conductive portion 22C) and the surface of the insulating particle 4C. In the coated particle 1C, the fluorine-containing organic compound 3C is disposed on the surface of the conductive particle 2C (the surface of the conductive portion 22C) and on the surface of the insulating particle 4C, and is in contact with the conductive particle 2C (the conductive portion 22C) and the insulating particle 4C.

[0047] In the coated particle 1C, the insulating particle 4C is disposed on the surface of the conductive particle 2C. In the coated particle 1C, the insulating particle 4C is disposed on the surface of the conductive portion 22C and is in contact with the conductive portion 22C.

[0048] The conductive portion 22C covers the surface of the base particle 21C. In the conductive particle 2C, the surface of the base particle 21C is covered with the conductive portion 22C. The conductive particle 2C has the conductive portion 22C on the surface.

[0049] In the coated particle 1C, the conductive portion 22C is a conductive layer. The conductive portion 22C is a single-layer conductive layer. In the conductive particle, the conductive portion may cover the entire surface of the base particle, or the conductive portion may cover only a portion of the surface of the base particle.

[0050] Coated particles 1C can be obtained, for example, by dipping conductive particles 2C having insulating particles 4C attached thereto into a dispersion of a fluorine-containing organic compound to form a fluorine-containing organic compound 3C. Coated particles 1D and 1E, which will be described later, can also be obtained in the same manner as coated particles 1C.

[0051] The difference between the coated particle 1 and the coated particle 1C is the presence or absence of insulating particles. The coated particle may or may not include insulating particles.

[0052] FIG. 5 is a cross-sectional view showing a covered particle according to a fifth embodiment of the present invention.

[0053] The coated particle 1D shown in Fig. 5 includes a conductive particle 2D, an organic compound 3D containing fluorine, and a plurality of insulating particles 4D. The coated particle 1D includes the conductive particle 2D, the organic compound 3D containing fluorine, and further includes a plurality of insulating particles 4D. In the coated particle 1D, a plurality of insulating particles 4D are arranged on the surface of the conductive particle 2D. In the coated particle 1D, the conductive particle 2D has a base particle 21D and a conductive portion 22D arranged on the surface of the base particle 21D.

[0054] In the coated particle 1D, the fluorine-containing organic compound 3D coats the surface of the conductive particle 2D (surface of the conductive portion 22D) and the surface of the insulating particle 4D. In the coated particle 1D, the fluorine-containing organic compound 3D is disposed on the surface of the conductive particle 2D (surface of the conductive portion 22D) and on the surface of the insulating particle 4D, and is in contact with the conductive particle 2D (conductive portion 22D) and the insulating particle 4D.

[0055] In the coated particle 1D, the insulating particle 4D is disposed on the surface of the conductive particle 2D. In the coated particle 1D, the insulating particle 4D is disposed on the surface of the conductive portion 22D and is in contact with the conductive portion 22D.

[0056] In coated particle 1D, conductive portion 22D is a two-layer conductive layer. Conductive portion 22D includes first conductive portion 22DA and second conductive portion 22DB. In conductive portion 22D, first conductive portion 22DA is laminated on the surface of base particle 21D, and second conductive portion 22DB is laminated on the surface of first conductive portion 22DA.

[0057] The structure of the conductive portion is different between coated particle 1C and coated particle 1D. The conductive portion may be a single conductive layer or multiple conductive layers.

[0058] FIG. 6 is a cross-sectional view showing a covered particle according to a sixth embodiment of the present invention.

[0059] The coated particle 1E shown in Fig. 6 includes a conductive particle 2E, an organic compound 3E containing fluorine, and a plurality of insulating particles 4E. The coated particle 1E includes a conductive particle 2E, an organic compound 3E containing fluorine, and further includes a plurality of insulating particles 4E. In the coated particle 1E, a plurality of insulating particles 4E are arranged on the surface of the conductive particle 2E. In the coated particle 1E, the conductive particle 2E includes a base particle 21E, a conductive portion 22E arranged on the surface of the base particle 21E, and a plurality of core materials 23E arranged on the surface of the base particle 21E.

[0060] In the coated particle 1E, the fluorine-containing organic compound 3E coats the surface of the conductive particle 2E (the surface of the conductive portion 22E) and the surface of the insulating particle 4E. In the coated particle 1E, the fluorine-containing organic compound 3E is disposed on the surface of the conductive particle 2E (the surface of the conductive portion 22E) and on the surface of the insulating particle 4E, and is in contact with the conductive particle 2E (the conductive portion 22E) and the insulating particle 4E.

[0061] In the coated particle 1E, the insulating particle 4E is disposed on the surface of the conductive particle 2E. In the coated particle 1E, the insulating particle 4E is disposed on the surface of the conductive portion 22E and is in contact with the conductive portion 22E.

[0062] In the coated particle 1E, the conductive portion 22E coats the base particle 21E and the core material 23E. Since the conductive portion 22E coats the core material 23E, the coated particle 1E and the conductive particle 2E have a plurality of protrusions 2Ea on the surface. The surface of the conductive portion 22E is raised by the core material 23E, and a plurality of protrusions 2Ea are formed.

[0063] Covered particles 1C and covered particles 1E differ in whether a core substance is used and in whether protrusions are present. The covered particles may or may not have protrusions on the surface.

[0064] Other details of the coated particles will be described below.

[0065] In this specification, "(meth)acrylate" refers to acrylate and methacrylate, "(meth)acrylic" refers to acrylic and methacrylic, and "(meth)acryloyl" refers to acryloyl and methacryloyl.

[0066] The particle diameter of the coated particles is preferably 0.5 μm or more, more preferably 1.0 μm or more, even more preferably 1.5 μm or more, and is preferably 10 μm or less, more preferably 5.0 μm or less, even more preferably 4.0 μm or less, even more preferably 3.5 μm or less, particularly preferably less than 3 μm, and most preferably 2.8 μm or less. When the particle diameter of the coated particles is equal to or greater than the lower limit, the connection resistance after conductive connection can be reduced. When the particle diameter of the coated particles is equal to or less than the upper limit, adjacent electrodes can be prevented from being short-circuited even in fan-pitch connection, and the connection reliability can be improved. Since the coated particles according to the present invention have the above configuration, even if the particle diameter of the coated particles is small, the initial connection resistance after conductive connection can be reduced, and the conduction reliability can be improved when used for a long period of time under high temperature and high humidity.

[0067] The particle size of the coated particles is preferably an average particle size, more preferably a number average particle size, and can be determined, for example, by observing 50 random coated particles with an electron microscope or optical microscope, calculating the average particle size of each coated particle, or by performing laser diffraction particle size distribution measurement.

[0068] From the viewpoint of more effectively exerting the effects of the present invention, the coefficient of variation (CV value) of the particle diameter of the coated particles is preferably 10% or less, more preferably 5% or less. The lower limit of the coefficient of variation (CV value) of the particle diameter of the coated particles is not particularly limited. The coefficient of variation (CV value) of the particle diameter of the coated particles may be 0%, 2% or more, or 5% or more.

[0069] The coefficient of variation (CV value) can be measured as follows.

[0070] CV value (%) = (ρ / Dn) × 100 ρ: Standard deviation of particle size of coated particles Dn: average particle size of coated particles

[0071] The shape of the coated particles is not particularly limited. The shape of the coated particles may be spherical or may be a shape other than spherical, such as flat.

[0072] In the above-mentioned coated particles, in TOF-SIMS analysis, the ratio of the fluorine ion intensity at the surface of the coated particles to the total ion intensity of all negative ions (fluorine ion intensity ratio) is preferably 0.0001 or more. The above-mentioned fluorine ion intensity ratio is expressed as a ratio (fluorine ion intensity at the surface of the coated particles / total ion intensity of all negative ions). The above-mentioned fluorine ion intensity ratio is preferably 0.0001 or more, more preferably 0.001 or more, even more preferably 0.005 or more, particularly preferably 0.01 or more, and preferably 0.1 or less, more preferably 0.05 or less. When the above-mentioned fluorine ion intensity ratio is the above-mentioned lower limit or more, the conductive reliability can be improved when used for a long period of time under high temperature and high humidity. When the above-mentioned fluorine ion intensity ratio is the above-mentioned upper limit or less, the initial connection resistance after conductive connection can be reduced, and the conductive reliability can be improved when used for a long period of time under high temperature and high humidity.

[0073] Specific measurement conditions for TOF-SIMS are, for example, as follows.

[0074] TOF-SIMS equipment: ION-TOF, TOF-SIMS5 model Primary ion: 209Bi3++ Ion voltage: 25kV Ion current: 1pA Mass range: 1 to 500 mass Analysis area: 500μm×500μm Charge prevention: Electron irradiation neutralization

[0075] The method of controlling the fluorine ion intensity ratio within the preferred range includes a method of adjusting the content of the fluorine-containing organic compound when disposing the fluorine-containing organic compound on the surface of the conductive particle, etc. The method of disposing the fluorine-containing organic compound on the surface of the conductive particle includes a method of disposing by dipping, a method of disposing by spraying, a method of disposing by melt coating, etc.

[0076] The coated particles are dispersed in a binder resin and are suitably used to obtain a resin composition.

[0077] <Base material particles> The base particles include resin particles, inorganic particles other than metal particles, organic-inorganic hybrid particles, and metal particles. The base particles are preferably base particles other than metal particles, and more preferably resin particles, inorganic particles other than metal particles, or organic-inorganic hybrid particles. The base particles may be core-shell particles having a core and a shell disposed on the surface of the core. The core may be an organic core, and the shell may be an inorganic shell.

[0078] Examples of materials for the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; acrylic resins such as polymethyl methacrylate and polymethyl acrylate; polycarbonate, polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polysulfone, polyphenylene oxide, polyacetal, polyimide, polyamideimide, polyether ether ketone, polyether sulfone, and divinylbenzene polymer. The divinylbenzene polymer may be a divinylbenzene copolymer. Examples of the divinylbenzene copolymer include a divinylbenzene-styrene copolymer and a divinylbenzene-(meth)acrylic acid ester copolymer. The material of the resin particles is preferably a polymer obtained by polymerizing one or more types of polymerizable monomers having an ethylenically unsaturated group, since this allows the hardness of the resin particles to be easily controlled within a suitable range.

[0079] When the resin particles are obtained by polymerizing a polymerizable monomer having an ethylenically unsaturated group, the polymerizable monomer having an ethylenically unsaturated group may be a non-crosslinkable monomer or a crosslinkable monomer.

[0080] Examples of the non-crosslinkable monomer include styrene-based monomers such as styrene and α-methylstyrene; carboxyl group-containing monomers such as (meth)acrylic acid, maleic acid, and maleic anhydride; alkyl (meth)acrylate compounds such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate; and 2-hydroxyethyl (meth)acrylate, glycerol (meth)acrylate, and the like. nitrile-containing monomers such as (meth)acrylonitrile; vinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether, and propyl vinyl ether; acid vinyl ester compounds such as vinyl acetate, vinyl butyrate, vinyl laurate, and vinyl stearate; unsaturated hydrocarbons such as ethylene, propylene, isoprene, and butadiene; and halogen-containing monomers such as trifluoromethyl (meth)acrylate, pentafluoroethyl (meth)acrylate, vinyl chloride, vinyl fluoride, and chlorostyrene.

[0081] Examples of the crosslinkable monomer include tetramethylolmethane tetra(meth)acrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol poly(meth)acrylate, pentaerythritol tetra(meth)acrylate, glycerol tri(meth)acrylate, glycerol di(meth)acrylate, (poly)ethylene glycol, Examples of the crosslinkable monomer include polyfunctional (meth)acrylate compounds such as 1,4-butanediol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, (poly)tetramethylene glycol di(meth)acrylate, and 1,4-butanediol di(meth)acrylate; triallyl (iso)cyanurate, triallyl trimellitate, divinylbenzene, diallyl phthalate, diallyl acrylamide, diallyl ether, and silane-containing monomers such as γ-(meth)acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, and vinyltrimethoxysilane. From the viewpoint of the resin particles retaining their shape even at the glass transition temperature of the resin particles, the crosslinkable monomer is preferably (poly)ethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, or dipentaerythritol poly(meth)acrylate.

[0082] The resin particles can be obtained by polymerizing the polymerizable monomer having an ethylenically unsaturated group by a known method, such as a method of suspension polymerization in the presence of a radical polymerization initiator, and a method of swelling and polymerizing a monomer together with a radical polymerization initiator using non-crosslinked seed particles.

[0083] When the base particle is an inorganic particle other than a metal particle or an organic-inorganic hybrid particle, examples of the inorganic material for forming the base particle include silica, alumina, barium titanate, zirconia, and carbon black. The inorganic material is preferably not a metal. Examples of the particles formed by silica include particles obtained by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups to form crosslinked polymer particles, and then baking the particles as necessary. Examples of the organic-inorganic hybrid particles include organic-inorganic hybrid particles formed by crosslinked alkoxysilyl polymer and acrylic resin.

[0084] The organic-inorganic hybrid particles are preferably core-shell type organic-inorganic hybrid particles having a core and a shell disposed on the surface of the core. The core is preferably an organic core. The shell is preferably an inorganic shell. From the viewpoint of effectively reducing the connection resistance between electrodes, the base particle is preferably an organic-inorganic hybrid particle having an organic core and an inorganic shell disposed on the surface of the organic core.

[0085] Examples of the material for the organic core include the materials for the resin particles described above.

[0086] The material of the inorganic shell may be any of the inorganic substances listed as the material of the base particle. The material of the inorganic shell is preferably silica. The inorganic shell is preferably formed by forming a shell-like material from a metal alkoxide on the surface of the core by a sol-gel method, and then firing the shell-like material. The metal alkoxide is preferably a silane alkoxide. The inorganic shell is preferably formed from a silane alkoxide.

[0087] When the base particles are metal particles, examples of the metal that is the material of the metal particles include silver, copper, nickel, silicon, gold, and titanium.

[0088] The particle diameter of the base particle is preferably 0.5 μm or more, more preferably 1.0 μm or more, and preferably 10 μm or less, more preferably 5.0 μm or less, even more preferably 4.0 μm or less, even more preferably 3.0 μm or less, particularly preferably 2.7 μm or less, and most preferably less than 2.7 μm. When the particle diameter of the base particle is equal to or more than the lower limit and equal to or less than the upper limit (or less than the upper limit), the connection resistance after conductive connection can be reduced. When the particle diameter of the base particle is equal to or less than the upper limit (or less than the upper limit), adjacent electrodes can be prevented from being short-circuited even in fan-pitch connection, and connection reliability can be improved. Since the coated particle according to the present invention has the above configuration, even if the particle diameters of the base particle and the coated particle are small, the initial connection resistance after conductive connection can be reduced, and the conductive reliability can be improved when used for a long period of time under high temperature and high humidity.

[0089] The shape of the base particle is not particularly limited, and may be spherical or a shape other than spherical, such as flat.

[0090] The particle diameter of the base particle indicates the number average particle diameter. The particle diameter of the base particle is measured using a particle size distribution measuring device or the like. The particle diameter of the base particle is preferably measured by observing 50 arbitrary base particles with an electron microscope or an optical microscope and calculating the average value. When measuring the particle diameter of the base particle in the coated particle, for example, it can be measured as follows.

[0091] The coated particles are added to "Technovit 4000" manufactured by Kulzer so that the content of the coated particles is 30% by weight, and dispersed to prepare an embedded resin body for testing containing the coated particles. A cross section of the coated particles is cut out using an ion milling device ("IM4000" manufactured by Hitachi High-Technologies Corporation) so as to pass through the vicinity of the center of the base particles dispersed in the embedded resin body for testing. Then, using a field emission scanning electron microscope (FE-SEM), the image magnification is set to 25,000 times, 50 coated particles are randomly selected, and the base particles of each coated particle are observed. The particle diameter of the base particles in each coated particle is measured, and the particle diameter of the base particles is determined by arithmetic averaging.

[0092] <Core substance and protrusions> The coated particles preferably have protrusions on the outer surface of the conductive part. The protrusions are preferably multiple. The conductive particles preferably have protrusions on the outer surface of the conductive part. The protrusions are preferably multiple. In general, an oxide film is often formed on the surface of an electrode that contacts the coated particles. When coated particles having protrusions on the surface are used, the oxide film can be effectively removed by the protrusions during conductive connection. Therefore, the electrode and the coated particles are more reliably in contact with each other, the contact area between the coated particles and the electrode can be sufficiently increased, and the connection resistance can be more effectively reduced. Furthermore, when the coated particles are dispersed in a binder resin and used as a resin composition or a conductive material, the protrusions of the coated particles can more effectively remove the binder resin between the coated particles and the electrode. Therefore, the contact area between the coated particles and the electrode can be sufficiently increased, and the connection resistance can be more effectively reduced.

[0093] Methods for forming protrusions on the surfaces of coated particles and conductive particles include a method in which a core substance is attached to the surface of a base particle and then a conductive portion is formed by electroless plating, and a method in which a conductive portion is formed on the surface of a base particle by electroless plating, then a core substance is attached, and then a conductive portion is formed by electroless plating.

[0094] Examples of the method for attaching the core substance to the surface of the base particle include a method of adding the core substance to a dispersion liquid of the base particle, and accumulating and attaching the core substance to the surface of the base particle by, for example, van der Waals force, and a method of adding the core substance to a container containing the base particle, and attaching the core substance to the surface of the base particle by a mechanical action such as rotating the container, etc. Among them, the method of accumulating and attaching the core substance to the surface of the base particle in the dispersion liquid is preferred because it is easy to control the amount of the core substance to be attached.

[0095] The conductive particle may have a first conductive portion on the surface of the base particle and a second conductive portion on the surface of the first conductive portion. In this case, a core material may be attached to the surface of the base particle, or the core material may be attached to the surface of the first conductive portion. The core material is preferably coated with the second conductive portion, and more preferably coated with the first conductive portion and the second conductive portion. The conductive particle is preferably obtained by attaching a core material to the surface of the base particle, forming a first conductive portion on the surfaces of the base particle and the core material, and then forming a second conductive portion on the surface of the first conductive portion.

[0096] The material constituting the core material includes conductive materials and non-conductive materials. The conductive material includes, for example, conductive non-metals such as metals, metal oxides, and graphite, and conductive polymers. The conductive polymer includes polyacetylene. The non-conductive material includes silica, alumina, and zirconia. From the viewpoint of increasing the conductivity, the material constituting the core material is preferably a metal. From the viewpoint of increasing the conductivity, the core material is preferably a metal particle.

[0097] Examples of the metal include gold, silver, copper, platinum, zinc, iron, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium, and cadmium, as well as alloys consisting of two or more metals, such as tin-lead alloy, tin-copper alloy, tin-silver alloy, tin-lead-silver alloy, and tungsten carbide. Among these, nickel, copper, silver, and gold are preferred. The metal constituting the core material may be the same as or different from the metal constituting the conductive portion (conductive layer).

[0098] The shape of the core material is not particularly limited. The core material is preferably in the form of a lump. Examples of the core material include a particulate lump, an aggregate of a plurality of microparticles, and an amorphous lump.

[0099] The average height of the plurality of protrusions is preferably 0.001 μm or more, more preferably 0.05 μm or more, and preferably 0.9 μm or less, more preferably 0.2 μm or less. When the average height of the protrusions is equal to or more than the lower limit and equal to or less than the upper limit, the connection resistance between the electrodes can be effectively reduced.

[0100] <Conductive part> In the present invention, the conductive particles have a conductive portion on a surface thereof. The conductive portion is disposed on the surface of the base particle.

[0101] The conductive portion preferably contains a metal. The metal constituting the conductive portion is not particularly limited. Examples of the metal include gold, silver, copper, tin, platinum, palladium, zinc, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium, and cadmium, as well as alloys thereof. In addition, tin-doped indium oxide (ITO) may be used as the metal. Only one of the above metals may be used, or two or more of them may be used in combination.

[0102] From the viewpoint of further improving the conduction reliability, the conductive portion preferably contains tin, nickel, palladium, copper or gold, more preferably contains tin or nickel, and further preferably contains nickel.

[0103] From the viewpoint of further improving the conduction reliability, the conductive part preferably contains nickel as a main metal. From the viewpoint of further improving the conduction reliability, the content of nickel in 100% by weight of the conductive part is preferably 15% by weight or more, more preferably 20% by weight or more, further preferably 25% by weight or more, and particularly preferably 30% by weight or more. The content of nickel in 100% by weight of the conductive part may be 100% by weight (total amount).

[0104] The conductive part may be formed of one layer. The conductive part may be formed of multiple layers. That is, the conductive part may have a laminated structure of two or more layers. When the conductive part is formed of multiple layers, the metal constituting the outermost layer is preferably tin, nickel, palladium, copper or gold, more preferably tin, nickel, palladium or copper, even more preferably tin or nickel, and particularly preferably nickel. When the metal constituting the outermost layer is one of these preferred metals, the connection resistance between the electrodes can be further reduced, and the conductive reliability can be further improved when used for a long period of time under high temperature and high humidity. In addition, when the metal constituting the outermost layer is gold, the corrosion resistance is further increased.

[0105] From the viewpoint of further improving the conduction reliability when used for a long period of time under high temperature and high humidity, it is preferable that the outer surface portion of the conductive part contains nickel. From the viewpoint of further improving the conduction reliability when used for a long period of time under high temperature and high humidity, when the conductive part has a laminated structure of two or more layers, it is preferable that the outermost layer contains nickel. When the conductive part has a single-layer structure, one conductive layer contains nickel.

[0106] The area of ​​the portion covered by the conductive portion (coverage rate by the conductive portion) of the total surface area of ​​the base particle (100%) is preferably 80% or more, more preferably 90% or more. The upper limit of the coverage rate by the conductive portion is not particularly limited. The coverage rate by the conductive portion may be 99% or less. When the coverage rate by the conductive portion is equal to or more than the lower limit and equal to or less than the upper limit, the electrical connection reliability can be further effectively improved when the electrodes are electrically connected.

[0107] The thickness of the conductive portion is preferably 0.005 μm or more, more preferably 0.01 μm or more, and is preferably 1 μm or less, more preferably 0.5 μm or less, and even more preferably 0.3 μm or less. When the thickness of the conductive portion is equal to or more than the lower limit and equal to or less than the upper limit, the electrical connection reliability can be more effectively improved, and the conductive particles can be sufficiently deformed when connecting the electrodes without becoming too hard.

[0108] When the conductive portion is formed of multiple layers, the thickness of the conductive portion of the outermost layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, and preferably 0.5 μm or less, more preferably 0.3 μm or less. When the thickness of the conductive portion of the outermost layer is equal to or more than the lower limit and equal to or less than the upper limit, the conductive portion of the outermost layer becomes uniform, the corrosion resistance becomes sufficiently high, and the connection resistance between the electrodes can be sufficiently low.

[0109] When the conductive portion is formed of multiple layers, the thickness of the conductive portion of the innermost layer is preferably 0.005 μm or more, more preferably 0.01 μm or more, and preferably 0.5 μm or less, more preferably 0.3 μm or less. When the thickness of the conductive portion of the innermost layer is equal to or more than the lower limit and equal to or less than the upper limit, the corrosion resistance is sufficiently high and the connection resistance between the electrodes can be sufficiently low.

[0110] The thickness of the conductive portion can be measured, for example, by observing a cross section of the conductive particle using a transmission electron microscope (TEM).

[0111] The method of forming the conductive portion on the surface of the base particle is not particularly limited. Examples of the method of forming the conductive portion include electroless plating, electroplating, physical collision, mechanochemical reaction, physical vapor deposition or physical adsorption, and a method of coating the surface of the base particle with a metal powder or a paste containing a metal powder and a binder. The method of forming the conductive portion is preferably electroless plating, electroplating, or a physical collision method. Examples of the physical vapor deposition method include vacuum deposition, ion plating, and ion sputtering. In addition, in the physical collision method, for example, a sheeter composer (manufactured by Tokuju Machine Works) is used.

[0112] <Organic compounds containing fluorine> In the coated particle according to the present invention, the organic compound containing fluorine coats at least a part of the surface of the conductive part. That is, the organic compound containing fluorine coats at least a part of the surface of the conductive particle. In the coated particle, the organic compound containing fluorine (coating part) is disposed on at least a part of the surface of the conductive part (conductive particle). When the coated particle further includes a plurality of insulating particles described later, from the viewpoint of more effectively exerting the effect of the present invention, it is preferable that the organic compound containing fluorine coats at least a part of the surface of the conductive part and at least a part of the surface of the insulating particle. In the coated particle, it is preferable that the organic compound containing fluorine (coating part) is disposed on at least a part of the surface of the conductive part and at least a part of the surface of the insulating particle. The organic compound containing fluorine may be a coating.

[0113] Since the coated particles according to the present invention have the above-mentioned configuration, oxidation of the conductive portion can be suppressed. In the coated particles, the fluorine-containing organic compound acts as a rust inhibitor.

[0114] In the case where the coated particle further includes a plurality of insulating particles described later, the fluorine-containing organic compound may or may not be disposed between the conductive portion and the insulating particle. The conductive portion and the insulating particle may be in direct contact with each other without the fluorine-containing organic compound therebetween.

[0115] From the viewpoint of exerting the effect of the present invention more effectively, the area of ​​the part covered by the fluorine-containing organic compound (coverage rate by the fluorine-containing organic compound) in the total surface area (100%) of the conductive part (conductive particle) is preferably 70% or more, more preferably 80% or more, even more preferably 90% or more, and most preferably 100%. From the viewpoint of exerting the effect of the present invention more effectively, it is preferable that the fluorine-containing organic compound covers the entire surface of the conductive part (conductive particle). From the viewpoint of exerting the effect of the present invention more effectively, it is preferable that the fluorine-containing organic compound covers the surface of the conductive part and the surface of the insulating particle. The coverage rate by the fluorine-containing organic compound can be measured by the following method.

[0116] Conductive particles are observed from one direction using a scanning electron microscope (SEM), and the total area of ​​the fluorine-containing organic compound within the circle of the outer periphery of the surface of the conductive part in the observed image is calculated from the total area within the circle of the outer periphery of the surface of the conductive part. The coverage rate with the fluorine-containing organic compound is preferably calculated as an average coverage rate by observing 20 coated particles and averaging the measurement results of each coated particle. The coverage rate with the insulating particles may be measured by mapping analysis such as EDX associated with the scanning electron microscope (SEM).

[0117] The above-mentioned organic compounds containing fluorine include polytetrafluoroethylene, tetrafluoroethylene-ethylene copolymers, polyvinylidene fluoride, perfluoroalkyl compounds, and polyfluoroalkyl compounds. The above-mentioned perfluoroalkyl compounds include perfluoroalkylsulfonic acids, perfluoroalkyl carboxylic acids, perfluoroalkyl phosphoric acids, and perfluoroalkyl amines. The above-mentioned polyfluoroalkyl compounds include polyfluoroalkylsulfonic acids, polyfluoroalkyl carboxylic acids, polyfluoroalkyl phosphoric acids, and polyfluoroalkyl amines.

[0118] From the viewpoint of easily coating the conductive particles, the fluorine-containing organic compound is preferably polyvinylidene fluoride, a perfluoroalkyl compound, or a polyfluoroalkyl compound, and more preferably a perfluoroalkyl compound.

[0119] From the viewpoint of more effectively exerting the effect of the present invention, the organic compound containing fluorine preferably has a functional group capable of ionic, covalent or coordinate bonding with metal, more preferably has a functional group capable of ionic, covalent or coordinate bonding with nickel, and even more preferably has a phosphate group. When the organic compound containing fluorine has a phosphate group, the surface of the conductive part can be more easily covered. From the viewpoint of more effectively exerting the effect of the present invention, the organic compound containing fluorine is preferably polyfluoroalkyl phosphate or perfluoroalkyl phosphate.

[0120] The fluorine-containing organic compound can be detected by the following method. The outermost surface of the particle is measured using time-of-flight secondary ion mass spectrometry (TOF-SIMS) to observe the presence or absence of a mass spectrum derived from the fluorine-containing organic compound. An example of an analyzer used for the TOF-SIMS is the "PHI nano TOFII" manufactured by ULVAC-PHI, Inc.

[0121] The method of disposing the fluorine-containing organic compound on the surface of the conductive particles is not particularly limited. Examples of the method of disposing the fluorine-containing organic compound on the surface of the conductive particles include a method of disposing by dipping, a method of disposing by spraying, and a method of disposing by melt coating.

[0122] In 100% by weight of the coated particles, the content of the fluorine-containing organic compound is preferably 0.001% by weight or more, more preferably 0.01% by weight or more, and is preferably 10% by weight or less, more preferably 5.0% by weight or less, even more preferably 1.0% by weight or less, particularly preferably 0.5% by weight or less, and most preferably 0.1% by weight or less. When the content of the fluorine-containing organic compound is equal to or more than the lower limit and equal to or less than the upper limit, the initial connection resistance after conductive connection can be reduced, and the conductive reliability can be increased when used for a long period of time under high temperature and high humidity.

[0123] <Insulating particles> The coated particles according to the present invention may or may not have insulating particles on the outer surface of the conductive particle. The coated particles according to the present invention may not have insulating particles arranged on the surface of the conductive particle. The coated particles may have a plurality of insulating particles arranged on the surface of the conductive particle. The coated particles may comprise a conductive particle with insulating particles and an organic compound containing fluorine, and the conductive particle with insulating particles may have a conductive particle and a plurality of insulating particles arranged on the surface of the conductive particle. It is preferable that the coated particles further comprise a plurality of insulating particles, and a plurality of the insulating particles are arranged on the surface of the conductive particle. When the coated particles comprise a plurality of insulating particles arranged on the surface of the conductive particle, the use of the coated particles for connecting electrodes can prevent a short circuit between adjacent electrodes. Specifically, when a plurality of coated particles come into contact with each other, insulating particles are present between the plurality of electrodes, so that a short circuit between adjacent electrodes in the horizontal direction can be prevented, not between upper and lower electrodes. In addition, when connecting electrodes, the insulating particles between the conductive particle and the electrode can be easily removed by pressing the coated particles with two electrodes. Furthermore, when the conductive particles have a plurality of protrusions on the outer surface of the conductive portion, the insulating particles between the conductive particles and the electrode can be removed even more easily.

[0124] The insulating particles are preferably polymers of a polymerizable compound. The polymerizable compound is not particularly limited. Examples of the polymerizable compound include the above-mentioned resin particle material. When electrodes are electrically connected to each other, the insulating particles are preferably resin particles from the viewpoint of improving the conduction reliability and the insulation reliability. From the viewpoint of more effectively improving the conduction reliability and the insulation reliability, the material of the resin particles is preferably a divinylbenzene-styrene copolymer. In addition, from the viewpoint of favorably disposing the insulating particles on the surface of the conductive portion, the insulating particles preferably do not contain an organic compound containing fluorine.

[0125] The method of disposing the insulating particles on the surface of the conductive part includes a chemical method, and a physical or mechanical method. The chemical method includes, for example, an interfacial polymerization method, a suspension polymerization method in the presence of particles, and an emulsion polymerization method. The physical or mechanical method includes a method using spray drying, hybridization, an electrostatic adhesion method, a spraying method, a dipping method, and a vacuum deposition method. From the viewpoint of more effectively increasing the insulation reliability and the conduction reliability when the electrodes are electrically connected, the method of disposing the insulating particles on the surface of the conductive part is preferably a physical method.

[0126] The particle diameter of the insulating particles can be appropriately selected depending on the particle diameter of the coated particles and the application of the coated particles. The particle diameter of the insulating particles is preferably 10 nm or more, more preferably 100 nm or more, even more preferably 200 nm or more, particularly preferably 300 nm or more, and is preferably 2000 nm or less, more preferably 1000 nm or less, even more preferably 800 nm or less, particularly preferably 500 nm or less. If the particle diameter of the insulating particles is the lower limit or more, when the coated particles are dispersed in the binder resin, the coated particles are less likely to contact each other. If the particle diameter of the insulating particles is the upper limit or less, it is not necessary to apply too much pressure or heat to a high temperature in order to remove the insulating particles between the electrodes and the conductive particles when connecting the electrodes.

[0127] The particle diameter of the insulating particles is preferably an average particle diameter. The average particle diameter means a number average particle diameter. The particle diameter of the insulating particles is determined using a particle size distribution measuring device or the like. The particle diameter of the insulating particles is preferably determined by observing 50 arbitrary insulating particles with an electron microscope or an optical microscope, calculating an average value, or by performing a laser diffraction particle size distribution measurement. When the particle diameter of the insulating particles in the coated particles is measured, it can be measured, for example, as follows.

[0128] The coated particles are added to "Technovit 4000" manufactured by Kulzer so that the content is 30% by weight, and dispersed to prepare an embedded resin body for testing containing the coated particles. A cross section of the coated particles is cut out using an ion milling device ("IM4000" manufactured by Hitachi High-Technologies Corporation) so as to pass through the vicinity of the center of the insulating particles in the coated particles dispersed in the embedded resin body for testing. Then, using a field emission scanning electron microscope (FE-SEM) set to an image magnification of 50,000 times, 50 coated particles are randomly selected, and the insulating particles of each coated particle are observed. The circle equivalent diameter of the insulating particles in each coated particle is measured as the particle diameter, and the arithmetic average of these is taken as the particle diameter of the insulating particles.

[0129] In the coated particles according to the present invention, two or more kinds of insulating particles having different particle sizes may be used in combination. By using two or more kinds of insulating particles having different particle sizes in combination, the insulating particles having smaller particle sizes can enter the gaps covered by the insulating particles having larger particle sizes, and the insulating particles can be arranged on the surfaces of the conductive particles more efficiently.

[0130] The insulating particles preferably have a particle size variation coefficient (CV value) of 20% or less. When the insulating particles have a particle size variation coefficient of 20% or less, the insulating particles in the resulting coated particles have a more uniform thickness, which makes it easier to apply a uniform pressure during conductive connection, and further reduces the connection resistance between electrodes.

[0131] The coefficient of variation (CV value) can be measured as follows.

[0132] CV value (%) = (ρ / Dn) × 100 ρ: Standard deviation of the particle size of insulating particles Dn: Average particle size of insulating particles

[0133] The shape of the insulating particles is not particularly limited, and may be spherical, may be a shape other than spherical, or may be flat or the like.

[0134] From the viewpoint of more effectively improving the conductivity reliability and insulation reliability when electrodes are electrically connected, the area of ​​the portion covered by the insulating particles (coverage rate by the insulating particles) out of the total surface area (100%) of the conductive portion is preferably 30% or more, more preferably 40% or more, and is preferably 70% or less, more preferably 60% or less.

[0135] The coverage by the insulating particles can be measured, for example, by the following method. The conductive particles with insulating particles are observed from one direction with a scanning electron microscope (SEM), and the coverage is calculated from the total area of ​​the insulating particles within a circle at the outer periphery of the surface of the conductive part in the observed image, relative to the total area within the circle at the outer periphery of the surface of the conductive part. The coverage by the insulating particles is preferably calculated as an average coverage by observing 20 conductive particles with insulating particles and averaging the measurement results for each conductive particle with insulating particles.

[0136] The coverage rate of the insulating particles can also be measured by mapping analysis such as EDX associated with the SEM.

[0137] The coverage rate of the insulating particles can be adjusted by, for example, the amount of the insulating particles added to the base particles, the mixing time, etc., and therefore the method for adjusting the coverage rate of the insulating particles is not particularly limited.

[0138] (Resin composition) The resin composition according to the present invention includes the above-mentioned coated particles and a binder resin. The above-mentioned coated particles are preferably dispersed in a binder resin and used. The above-mentioned coated particles are preferably dispersed in a binder resin and used as a resin composition. The above-mentioned resin composition is preferably a conductive material, more preferably an anisotropic conductive material. The above-mentioned conductive material is preferably used for electrical connection between electrodes. The above-mentioned conductive material is preferably a conductive material for circuit connection. Since the above-mentioned coated particles are used in the above-mentioned resin composition and conductive material, aggregation of particles in the binder resin can be suppressed. In addition, when electrodes are electrically connected, the conduction reliability can be effectively improved. Furthermore, it is possible to prevent the insulating particles from being unintentionally detached from the surface of the coated particles before conductive connection such as dispersing the above-mentioned coated particles in the binder resin, and the insulation reliability between the electrodes can be further improved.

[0139] The binder resin is not particularly limited. A known insulating resin is used as the binder resin. The binder resin preferably contains a thermoplastic component (thermoplastic compound) or a curable component, and more preferably contains a curable component. Examples of the curable component include a photocurable component and a thermosetting component. The photocurable component preferably contains a photocurable compound and a photopolymerization initiator. The thermosetting component preferably contains a thermosetting compound and a thermosetting agent.

[0140] Examples of the binder resin include vinyl resins, thermoplastic resins, curable resins, thermoplastic block copolymers, elastomers, etc. The binder resins may be used alone or in combination of two or more.

[0141] Examples of the vinyl resin include vinyl acetate resin, acrylic resin, and styrene resin. Examples of the thermoplastic resin include polyolefin resin, ethylene-vinyl acetate copolymer, and polyamide resin. Examples of the curable resin include epoxy resin, urethane resin, polyimide resin, and unsaturated polyester resin. The curable resin may be a room temperature curable resin, a thermosetting resin, a photocurable resin, or a moisture curable resin. The curable resin may be used in combination with a curing agent. Examples of the thermoplastic block copolymer include styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, hydrogenated product of styrene-butadiene-styrene block copolymer, and hydrogenated product of styrene-isoprene-styrene block copolymer. Examples of the elastomer include styrene-butadiene copolymer rubber, and acrylonitrile-styrene block copolymer rubber.

[0142] In addition to the coated particles and the binder resin, the resin composition may contain various additives such as a filler, an extender, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, a lubricant, an antistatic agent, and a flame retardant.

[0143] The method for dispersing the coated particles in the binder resin can be a conventionally known dispersion method, and is not particularly limited. Examples of the method for dispersing the coated particles in the binder resin include the following methods. A method in which the coated particles are added to the binder resin, and then kneaded and dispersed with a planetary mixer or the like. A method in which the coated particles are uniformly dispersed in water or an organic dispersion medium using a homogenizer or the like, and then added to the binder resin, and then kneaded and dispersed with a planetary mixer or the like. A method in which the binder resin is diluted with water or an organic dispersion medium, and then the coated particles are added, and then kneaded and dispersed with a planetary mixer or the like.

[0144] The viscosity (η25) of the resin composition at 25°C is preferably 30 Pa·s or more, more preferably 50 Pa·s or more, and preferably 400 Pa·s or less, more preferably 300 Pa·s or less. When the viscosity of the resin composition at 25°C is equal to or more than the lower limit and equal to or less than the upper limit, the insulation reliability between electrodes can be more effectively improved, and the conduction reliability between electrodes can be more effectively improved. The viscosity (η25) can be appropriately adjusted by the types and amounts of the components.

[0145] The viscosity (η25) can be measured, for example, using an E-type viscometer ("TVE22L" manufactured by Toki Sangyo Co., Ltd.) under conditions of 25° C. and 5 rpm.

[0146] When the resin composition according to the present invention is a conductive material, the conductive material can be used as a conductive paste, a conductive film, or the like. When the conductive material is a conductive film, a film not containing conductive particles may be laminated on a conductive film containing conductive particles. The conductive paste is preferably an anisotropic conductive paste. The conductive film is preferably an anisotropic conductive film.

[0147] In 100% by weight of the resin composition, the content of the binder resin is preferably 10% by weight or more, more preferably 30% by weight or more, even more preferably 50% by weight or more, particularly preferably 70% by weight or more, and is preferably 99.99% by weight or less, more preferably 99.9% by weight or less. When the content of the binder resin is equal to or more than the lower limit and equal to or less than the upper limit, the conductive particles are efficiently arranged between the electrodes, and the connection reliability of the connection target members connected by the resin composition can be further improved.

[0148] In 100% by weight of the resin composition, the content of the coated particles is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, and is preferably 80% by weight or less, more preferably 60% by weight or less, even more preferably 40% by weight or less, particularly preferably 20% by weight or less, and most preferably 10% by weight or less. When the content of the coated particles is equal to or more than the lower limit and equal to or less than the upper limit, the electrical conductivity reliability and the insulation reliability between the electrodes can be further improved.

[0149] From the viewpoint of exerting the effect of the present invention more effectively, the ratio of the non-aggregated coated particles in the total number of the coated particles in the binder resin is preferably 60% or more, more preferably 70% or more, even more preferably 80% or more, particularly preferably 85% or more, and most preferably 90% or more. The upper limit of the ratio of the non-aggregated coated particles in the total number of the coated particles in the binder resin is not particularly limited. The ratio of the non-aggregated coated particles in the total number of the coated particles in the binder resin may be 100% (total amount).

[0150] (Connection structure) The connection structure according to the present invention comprises a first connection target member having a first electrode on its surface, a second connection target member having a second electrode on its surface, and a connection part connecting the first connection target member and the second connection target member. In the connection structure according to the present invention, the material of the connection part contains the above-mentioned coated particles. In the connection structure according to the present invention, the first electrode and the second electrode are electrically connected by the conductive particles.

[0151] The connection structure can be obtained through a step of disposing the coated particles between the first connection target member and the second connection target member, and a step of electrically connecting the first connection target member and the second connection target member by thermocompression bonding. During the thermocompression bonding, it is preferable that the fluorine-containing organic compound is detached from the coated particles. When the coated particles include the insulating particles, it is preferable that the insulating particles are detached from the coated particles during the thermocompression bonding. Moreover, the resin composition may be disposed instead of the coated particles.

[0152] FIG. 7 is a cross-sectional view that illustrates a connection structure using the covered particles according to the first embodiment of the present invention.

[0153] The connection structure 81 shown in FIG. 7 includes a first connection target member 82, a second connection target member 83, and a connection portion 84 connecting the first connection target member 82 and the second connection target member 83. The material of the connection portion 84 includes the coated particles 1. The connection portion 84 may be formed from a resin composition including the coated particles 1. The connection portion 84 is preferably formed by curing a resin composition including a plurality of coated particles 1. In FIG. 7, the coated particles 1 are shown diagrammatically for convenience of illustration. Instead of the coated particles 1, coated particles 1A or coated particles 1B may be used.

[0154] The first connection target member 82 has a plurality of first electrodes 82a on its surface (upper surface). The second connection target member 83 has a plurality of second electrodes 83a on its surface (lower surface). The first electrodes 82a and the second electrodes 83a are electrically connected by one or more conductive particles 2 (omitted in FIG. 7) in the coated particles 1. Therefore, the first connection target member 82 and the second connection target member 83 are electrically connected by the conductive portion 22 (omitted in FIG. 7) in the conductive particle 2 (omitted in FIG. 7).

[0155] The method for producing the connection structure is not particularly limited. One example of the method for producing the connection structure is to place the coated particles or the resin composition between a first connection target member and a second connection target member, obtain a laminate, and then heat and press the laminate. The pressure of the thermocompression bonding is preferably 40 MPa or more, more preferably 60 MPa or more, and preferably 90 MPa or less, more preferably 70 MPa or less. The temperature (heating temperature) of the thermocompression bonding is preferably 80° C. or more, more preferably 100° C. or more, and preferably 140° C. or less, more preferably 120° C. or less. When the pressure and temperature of the thermocompression bonding are equal to or more than the lower limit and equal to or less than the upper limit, the fluorine-containing organic compound can be easily detached from the surface of the coated particles during conductive connection, and the reliability of conduction between electrodes can be further improved.

[0156] When the laminate is heated and pressurized, the fluorine-containing organic compound present between the conductive particles and the first and second electrodes can be eliminated. During the heating and pressurization, some of the fluorine-containing organic compound may be eliminated from the surface of the conductive particles, causing the surface of the conductive portion to be partially exposed. The exposed surface of the conductive portion comes into contact with the first and second electrodes, thereby electrically connecting the first and second electrodes via the conductive particles.

[0157] The first connection target member and the second connection target member are not particularly limited. Specific examples of the first connection target member and the second connection target member include electronic components such as semiconductor chips, semiconductor packages, LED chips, LED packages, capacitors, and diodes, as well as electronic components such as resin films, printed circuit boards, flexible printed circuit boards, flexible flat cables, rigid flexible boards, glass epoxy boards, and glass boards. The first connection target member and the second connection target member are preferably electronic components.

[0158] Examples of the electrodes provided on the connection target members include metal electrodes such as gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, copper electrodes, molybdenum electrodes, silver electrodes, SUS electrodes, and tungsten electrodes. When the connection target members are flexible printed circuit boards, the electrodes are preferably gold electrodes, nickel electrodes, tin electrodes, silver electrodes, or copper electrodes. When the connection target members are glass substrates, the electrodes are preferably aluminum electrodes, copper electrodes, molybdenum electrodes, silver electrodes, or tungsten electrodes. When the electrodes are aluminum electrodes, they may be electrodes made of aluminum only, or may be electrodes in which an aluminum layer is laminated on the surface of a metal oxide layer. Examples of materials for the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal element include Sn, Al, and Ga.

[0159] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0160] The following materials were prepared:

[0161] Base material particles: Divinylbenzene resin particles (base particle A, Sekisui Chemical Co., Ltd. "Micropearl EX", particle size (average particle size) 2.55 μm) Divinylbenzene resin particles (base particle B, Sekisui Chemical Co., Ltd. "Micropearl EX", particle size (average particle size) 1.30 μm) Divinylbenzene resin particles (base particle C, Sekisui Chemical Co., Ltd. "Micropearl EX", particle size (average particle size) 1.80 μm) Divinylbenzene resin particles (base particle D, Sekisui Chemical Co., Ltd. "Micropearl EX", particle size (average particle size) 3.55 μm) Divinylbenzene resin particles (base particle E, Sekisui Chemical Co., Ltd. "Micropearl EX", particle size (average particle size) 4.55 μm)

[0162] Covering Material: Polyvinylidene fluoride (organic compound containing fluorine, "Polyvinylidene fluoride" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) Perfluoroalkyl phosphate (organic compound containing fluorine, "Surflon FPE-50" manufactured by AGC Seimi Chemical Co., Ltd.) Perfluoroalkyl (organic compounds containing fluorine, "S-656" manufactured by AGC Seimi Chemical Co., Ltd.) Monohexyl phosphate (a fluorine-free organic compound, "Monoethylhexyl Phosphate" manufactured by Tokyo Chemical Industry Co., Ltd.) Silicone compound (fluorine-free organic compound, Momentive's "TSF4700")

[0163] Example 1 (1) Preparation of conductive particles The base particle A was subjected to electroless plating to obtain conductive particles in which a nickel layer (thickness: 0.1 μm) was formed on the surface of the base particle A.

[0164] (2) Preparation of coated particles 10 g of the obtained conductive particles were placed in 100 g of an acetone solution in which polyvinylidene fluoride (coating material) was dissolved at 1 wt %, and ultrasonically stirred for 30 minutes at 50° C. Thereafter, the particles were filtered through a 10 μm mesh filter, washed with methanol, and then dried to obtain coated particles in which the surfaces of the conductive particles were coated with polyvinylidene fluoride.

[0165] (3) Preparation of resin composition (anisotropic conductive paste) 7 parts by weight of the obtained coated particles, 25 parts by weight of bisphenol A type phenoxy resin, 4 parts by weight of fluorene type epoxy resin, 30 parts by weight of phenol novolac type epoxy resin, and SI-60L (manufactured by Sanshin Chemical Industry Co., Ltd.) were mixed, and the mixture was degassed and stirred for 3 minutes to obtain resin composition A (anisotropic conductive paste).

[0166] (4) Fabrication of connection structure A transparent glass substrate was prepared with an IZO electrode pattern (first electrode, Vickers hardness of the metal on the electrode surface 100Hv) with an L / S of 10μm / 10μm formed on the top surface, and a semiconductor chip was prepared with an Au electrode pattern (second electrode, Vickers hardness of the metal on the electrode surface 50Hv) with an L / S of 10μm / 10μm formed on the bottom surface.

[0167] The obtained resin composition A (anisotropic conductive paste) was applied to the transparent glass substrate to a thickness of 30 μm to form an anisotropic conductive paste layer. Next, the semiconductor chip was laminated on the anisotropic conductive paste layer so that the electrodes faced each other. Then, a pressure heating head was placed on the upper surface of the semiconductor chip while adjusting the temperature of the head so that the temperature of the anisotropic conductive paste layer was 100° C., and a pressure of 60 MPa was applied to harden the anisotropic conductive paste layer at 100° C. to obtain a connection structure.

[0168] (Examples 2 to 6 and 8 to 11, and Comparative Examples 2 to 4) Covered particles, resin compositions, and connection structures were obtained in the same manner as in Example 1, except that the type of base particle, the configuration of the conductive portion, and the type of coating material were changed as shown in Tables 1 to 4 below.

[0169] Example 7 The base particle A was electrolessly plated to form a nickel layer (thickness 0.1 μm) on the surface of the base particle A. Then, a tin layer (thickness 0.01 μm) was formed by electrolessly plating to obtain conductive particles having a nickel layer and a tin layer formed on the surface of the base particle A. Except for using the obtained conductive particles and changing the type of coating material as shown in Table 2, coated particles, resin compositions, and connection structures were obtained in the same manner as in Example 1.

[0170] Comparative Example 1 Conductive particles were obtained in the same manner as in Example 1, except that the configuration of the conductive particles was changed as shown in Table 4 below. A resin composition and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particles were not coated but used as uncoated particles. In the following explanations and tables, "coated particles" for Comparative Example 1 will be read as "uncoated particles".

[0171] (evaluation) (1) Fluorine ion intensity ratio The obtained coated particles were subjected to TOF-SIMS analysis under the measurement conditions described above, and the ratio of the fluorine ion intensity on the surface of the coated particles to the sum of the ion intensities of all negative ions (fluorine ion intensity ratio) was measured.

[0172] (2) Initial connection resistance The volume resistivity of 2 g of the resulting coated particles at 20 kN was measured using a resistivity meter ("Powder Resistivity Measurement System" manufactured by Mitsubishi Chemical Corporation), and the average was taken as the volume resistivity (initial). The initial connection resistance was evaluated according to the following criteria.

[0173] [Initial connection resistance criteria] ○○: Volume resistivity (initial) is less than 0.002 Ω cm ○: Volume resistivity (initial) is 0.002 Ω cm or more and less than 0.005 Ω cm ×: Volume resistivity (initial) is 0.005 Ω cm or more

[0174] (3) Long-term connection resistance (conductivity reliability) The obtained coated particles were left for 500 hours at 85°C and 85% RH. After leaving, the volume resistivity of 2 g of the coated particles at 20 kN was measured using a resistivity meter ("Powder Resistivity Measurement System" manufactured by Mitsubishi Chemical Corporation), and the average was taken as the volume resistivity (long-term). The long-term connection resistance was judged according to the following criteria. The ratio (volume resistivity (long-term) / volume resistivity (initial)) was also calculated.

[0175] [Long-term connection resistance criteria] ○○○: Volume resistivity (long term) is less than 0.004 Ω cm ○○: Volume resistivity (long term) is 0.004 Ω·cm or more and less than 0.006 Ω·cm ○: Volume resistivity (long term) is 0.006 Ω cm or more and less than 0.01 Ω cm ×: Volume resistivity (long term) is 0.01 Ω cm or more

[0176] (4) Conduction reliability of connection structure The 20 connection structures obtained were left at 85°C and 85% RH for 500 hours, and then the connection resistance between the upper and lower electrodes was measured by the four-terminal method. Note that, based on the relationship of voltage = current x resistance, the connection resistance can be calculated by measuring the voltage when a constant current is applied. The electrical reliability of the connection structures was evaluated according to the following criteria.

[0177] [Criteria for determining the continuity reliability of connection structures] ○○: Connection resistance is 3.0Ω or less ○: Connection resistance is over 3.0Ω and 10.0Ω or less ×: Connection resistance exceeds 10.0Ω

[0178] The compositions of the coated particles and the results are shown in Tables 1 to 4 below.

[0179] [Table 1]

[0180] [Table 2]

[0181] [Table 3]

[0182] [Table 4] [Explanation of symbols]

[0183] 1, 1A, 1B, 1C, 1D, 1E...Coated particles 2,2A,2B,2C,2D,2E…conductive particles 2Ba,2Ea…protrusion 3,3A,3B,3C,3D,3E…Organic compounds containing fluorine 4C,4D,4E…Insulating particles 21,21A,21B,21C,21D,21E...Base material particles 22,22A,22B,22C,22D,22E...Conductive part 22AA, 22DA...First conductive portion 22AB, 22DB...Second conductive part 23B,23E…core material 81...Connection structure 82...First connection target member 82a...first electrode 83...Second connecting member 83a...second electrode 84…Connection

Claims

1. The conductive particles and the organic compound containing fluorine are included, the conductive particle has a base particle and a conductive portion disposed on a surface of the base particle, the conductive portion contains nickel, The coated particles have the fluorine-containing organic compound covering at least a part of the surface of the conductive portion.

2. The coated particles according to claim 1 , wherein the fluorine-containing organic compound is polyvinylidene fluoride, a perfluoroalkyl compound, or a polyfluoroalkyl compound.

3. 3. The coated particle according to claim 1, wherein in a TOF-SIMS analysis, the ratio of the fluorine ion intensity at the surface of the coated particle to the sum of the ion intensities of all negative ions is 0.0001 or more.

4. The coated particle according to claim 1 or 2, wherein the outer surface portion of the conductive portion contains nickel.

5. The coated particle according to claim 1 or 2, wherein the fluorine-containing organic compound has a phosphate group.

6. The coated particles according to claim 1 or 2, wherein the particle diameter of the coated particles is 1.0 μm or more and 4.0 μm or less.

7. further comprising a plurality of insulating particles; The coated particle according to claim 1 or 2, wherein a plurality of the insulating particles are disposed on the surface of the conductive particle.

8. The coated particles according to claim 1 or 2, wherein no insulating particles are disposed on the surfaces of the conductive particles.

9. A resin composition comprising the coated particles according to claim 1 or 2 and a binder resin.

10. a first connection target member having a first electrode on a surface thereof; a second connection target member having a second electrode on its surface; a connection portion that connects the first connection target member and the second connection target member, The material of the connection portion comprises the coated particles according to claim 1 or 2, A connection structure in which the first electrode and the second electrode are electrically connected by the conductive particles.

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