WO2022239776A1

WO2022239776A1 - Conductive particles, conductive material, and connection structure

Info

Publication number: WO2022239776A1
Application number: PCT/JP2022/019834
Authority: WO
Inventors: 豪湯川
Original assignee: 積水化学工業株式会社
Priority date: 2021-05-12
Filing date: 2022-05-10
Publication date: 2022-11-17
Also published as: KR20240006491A; JPWO2022239776A1; CN117296109A; TW202248385A

Abstract

Provided are conductive particles which enable effective removal of oxide films on the surfaces of the conductive particles and the surfaces of electrodes and effective improvement in conduction reliability at the time of electrical connection between the electrodes.　Conductive particles according to the present invention each comprise: a conductive particle body; a plurality of flux-containing particles; and a flux film. The conductive particle body includes a base material particle, and a conductive part disposed outside the base material particle. The flux-containing particles are arranged outside the conductive particle body, and the flux film is disposed outside the conductive particle body.

Description

Conductive particles, conductive materials and connecting structures

The present invention relates to conductive particles using flux. The present invention also relates to a conductive material and a connection structure using the conductive particles.

Anisotropic conductive materials such as anisotropic conductive paste and anisotropic conductive film are widely known. In the anisotropic conductive material, conductive particles are dispersed in a binder resin.

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

For example, when electrically connecting an electrode of a flexible printed circuit board and an electrode of a glass epoxy board using the anisotropic conductive material, an anisotropic conductive material containing conductive particles is placed on the glass epoxy board. do. Next, the flexible printed circuit board is laminated and heated and pressurized. As a result, the anisotropic conductive material is cured and the electrodes are electrically connected via the conductive particles to obtain a connection structure.

With the conductive particles and the anisotropic conductive material, an oxide film may be formed on the surface of the conductive portion of the conductive particles depending on storage conditions before conductive connection. Also, an oxide film may be formed on the surface of the electrodes to be electrically connected. The presence of this oxide film causes an increase in connection resistance and a decrease in conduction reliability in a connection structure that is electrically connected. In order to remove the oxide film on the surfaces of the conductive particles and the electrodes, flux may be added to the anisotropic conductive material or placed on the surfaces of the conductive particles.

Patent Document 1 below discloses a conductive adhesive composition containing (A) conductive particles containing a metal having a melting point of 220° C. or lower, (B) a thermosetting resin, and (C) a flux activator. It is (C) The flux activator has an average particle size of 15 μm or less.

Patent Document 2 below discloses an anisotropic conductive film having metal particles in an insulating film. In the anisotropic conductive film, the metal particles are regularly arranged in plan view, and at least one end of the metal particles on the front side of the anisotropic conductive film or the back side of the anisotropic conductive film is arranged so that the flux is in contact with or close to In the metal particles of Patent Document 2, the flux is in contact with or close to the ends of the metal particles.

WO2012/102077A1 WO2016/114160A1

When conducting a conductive connection using a conductive material containing conductive particles, a plurality of upper electrodes and a plurality of lower electrodes are electrically connected to form a conductive connection. The conductive particles are preferably located between the top and bottom electrodes and not between adjacent lateral electrodes. It is desirable that there is no electrical connection between adjacent lateral electrodes.

In conventional conductive materials such as those described in

Patent Documents

1 and 2, the flux as a whole is rapidly activated on the surface of the conductive particles or electrodes by heating and pressurization during conductive connection, and the activating ability of the flux is enhanced. prone to early loss. For this reason, it may not be possible to sufficiently remove the oxide film on the surface of the conductive particles. As a result, the connection resistance between the upper and lower electrodes to be connected increases, and the reliability of conduction may decrease.

An object of the present invention is to effectively remove the oxide film on the surface of the conductive particles and the surface of the electrodes, and to effectively increase the reliability of conduction when the electrodes are electrically connected. An object of the present invention is to provide conductive particles capable of Another object of the present invention is to provide a conductive material and a connection structure using the conductive particles.

According to a broad aspect of the present invention, a conductive particle body, a plurality of flux-containing particles, and a flux film are provided, and the conductive particle body is disposed outside the substrate particles and the substrate particles. and a conductive portion, wherein the flux-containing particles are arranged outside the conductive particle body, and the flux film is arranged outside the conductive particle body. .

In a specific aspect of the conductive particles according to the present invention, the flux-containing particles contain particle bodies and flux, and the particle bodies are resin particles.

In a specific aspect of the conductive particles according to the present invention, the material of the resin particles contains a polymerizable monomer, and the homopolymer of the polymerizable monomer has a glass transition temperature of 80° C. or higher. .

In a specific aspect of the conductive particles according to the present invention, the flux-containing particles have a breaking point in the compression-displacement curve when a maximum test load of 3.3 mN is applied to the flux-containing particles for 10 seconds. do not do.

In a specific aspect of the conductive particles according to the present invention, the conductive portion contains tin.

In a specific aspect of the conductive particles according to the present invention, the ratio of the particle size of the conductive particles to the particle size of the flux-containing particles is 3 or more and 500 or less.

In a specific aspect of the conductive particles according to the present invention, the conductive particles have a particle diameter of 1 μm or more and 50 μm or less.

In a specific aspect of the conductive particles according to the present invention, when a conductive particle-containing liquid obtained by adding 3 parts by weight of the conductive particles to 100 parts by weight of ethanol is subjected to ultrasonic treatment for 5 minutes at 20 ° C. and 40 kHz In addition, the residual rate of flux-containing particles determined by the following formula (1) is 99% or less.

Remaining rate of flux-containing particles (%) = (coverage rate of flux-containing particles after ultrasonic treatment/coverage rate of flux-containing particles before ultrasonic treatment) x 100... formula (1)

A broad aspect of the present invention provides a conductive material containing the above-described conductive particles and a binder resin.

According to a broad aspect of the present invention, a first member to be connected having a first electrode on its surface, a second member to be connected having a second electrode on its surface, the first member to be connected, a connecting portion connecting the second member to be connected, wherein the material of the connecting portion contains the conductive particles described above, and the first electrode and the second electrode are electrically conductive. A connection structure is provided that is electrically connected by the particle bodies.

A conductive particle according to the present invention comprises a conductive particle body, a plurality of flux-containing particles, and a flux film. In the conductive particle according to the present invention, the conductive particle main body includes a substrate particle and a conductive portion arranged outside the substrate particle. In the conductive particles according to the present invention, the flux-containing particles are arranged outside the conductive particle body, and the flux film is arranged outside the conductive particle body. Since the conductive particles according to the present invention have the above configuration, the oxide film on the surfaces of the conductive particles and the electrodes can be effectively removed, and the electrodes are electrically connected. In this case, the conduction reliability can be effectively improved.

FIG. 1 is a cross-sectional view showing conductive particles according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing conductive particles according to a second embodiment of the present invention. FIG. 3 is a cross-sectional view showing conductive particles according to a third embodiment of the present invention. FIG. 4 is a cross-sectional view showing conductive particles according to a fourth embodiment of the present invention. FIG. 5 is a cross-sectional view schematically showing a connected structure using conductive particles according to the first embodiment of the present invention.

The details of the present invention will be described below.

(Conductive particles)
A conductive particle according to the present invention includes a conductive particle body, a plurality of flux-containing particles, and a flux film. In the conductive particle according to the present invention, the conductive particle main body includes a substrate particle and a conductive portion arranged outside the substrate particle. In the conductive particles according to the present invention, the flux-containing particles are arranged outside the conductive particle body, and the flux film is arranged outside the conductive particle body.

Since the conductive particles according to the present invention have the above configuration, the surface of the conductive particles (specifically, the surface of the conductive portion of the conductive particles) and the oxide film on the surface of the electrode are effectively removed. When it can be removed and the electrodes are electrically connected, the reliability of conduction can be effectively improved.

With conventional conductive particles and conductive materials, the entire flux component is quickly activated on the surface of the conductive particles or electrodes due to heating and pressurization during conductive connection, and the flux tends to lose its activating ability early. For this reason, it may not be possible to sufficiently remove the oxide film on the surface of the conductive particles. As a result, the connection resistance between the upper and lower electrodes to be connected increases, and the reliability of conduction may decrease.

As a result of intensive studies, the inventor found that the above problems can be solved by using conductive particles having a specific configuration. In the conductive particles according to the present invention, the oxide film on the surface of the conductive particles and the surface of the electrode is effectively removed by the flux film in the initial stage of conductive connection by heating and pressurizing at the time of conductive connection. be able to. Furthermore, in the conductive particles according to the present invention, the flux gradually leaks from the flux-containing particles due to heating and pressurization at the time of conductive connection. can be removed. In addition, in the present invention, the flux gradually leaks from the flux-containing particles even after the conductive connection, so that the oxide film on the surface of the conductive particles and the surface of the electrode can be removed. As a result, it is possible to effectively improve the reliability of conduction between the upper and lower electrodes to be connected.

In addition, in the conductive particles according to the present invention, the flux-containing particles are easily detached from the upper and lower surfaces of the conductive particle body due to the vertical mounting stress applied to the conductive particles during conductive connection. This makes it difficult for the flux-containing particles to remain between the conductive particle body and the electrode, and as a result, it is possible to effectively improve the reliability of conduction between the upper and lower electrodes to be connected. In addition, since stress in the horizontal direction is less likely to be applied to the conductive particles at the time of conductive connection, the flux-containing particles are less likely to detach from the surfaces in the horizontal direction of the main body of the conductive particles. As a result, the conductive particles according to the present invention can effectively improve the insulation reliability between laterally adjacent electrodes that should not be connected.

Therefore, in the present invention, it is possible to effectively improve conduction reliability and insulation reliability when the electrodes are electrically connected.

Furthermore, since the present invention has the above configuration, it is possible to reduce the flux content compared to conventional conductive particles and conductive materials. In the present invention, with a small amount of flux, the oxide film on the surface of the conductive particles and the surface of the electrode can be effectively removed, and when the electrodes are electrically connected, the conduction reliability is effectively improved. can be increased to

The conductive particles are dispersed in a binder resin and are suitably used to obtain a conductive material.

Specific embodiments of the present invention will be described below with reference to the drawings. In addition, in FIG. 1 and the figures described later, different parts can be replaced with each other. In addition, 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. For example, the thickness of the flux film may be fairly thin.

FIG. 1 is a cross-sectional view showing conductive particles according to the first embodiment of the present invention.

The conductive particle 1 shown in FIG. 1 includes a conductive particle body 11, a plurality of flux-containing particles 12, and a flux film 13. In the conductive particle 1 , the conductive particle body 11 includes the base particle 21 and the conductive part 22 arranged outside the base particle 21 . In the conductive particles 1 , the flux-containing particles 12 are arranged outside the conductive particle body 11 . In the conductive particles 1 , the flux film 13 is arranged outside the conductive particle body 11 . The conductive portion 22 is arranged on the surface of the substrate particle 21 and is in contact with the substrate particle 21 . In the conductive particles 1, the flux-containing particles 12 are arranged on the surface of the conductive particle body 11 (conductive portion 22) and are in contact with the conductive particle body 11 (conductive portion 22). In the conductive particles 1, the flux film 13 is arranged on the surface of the conductive particle body 11 (conductive portion 22) and is in contact with the conductive particle body 11 (conductive portion 22).

The conductive portion 22 covers the surfaces of the base particles 21 . The conductive particle body 11 is a coated particle in which the surface of the base particle 21 is coated with the conductive part 22 . The conductive particle body 11 has a conductive portion 22 on its surface.

In the conductive particles 1, the conductive portion 22 is a conductive layer. The conductive portion 22 is a single-layer conductive layer. In the conductive particles, the conductive portion may cover the entire surface of the substrate particle, or the conductive portion may cover a portion of the surface of the substrate particle.

In the conductive particles 1 , the flux film 13 covers the surface of the conductive particle body 11 (the surface of the conductive portion 22 ) and the surface of the flux-containing particles 12 .

The conductive particles 1 can be obtained, for example, by using the conductive particle body 11 to which the flux-containing particles 12 are attached before the flux film 13 is arranged, and forming the flux film 13 by flux treatment. Conductive particles 1B and 1C, which will be described later, can also be obtained in the same manner as the conductive particles 1.

FIG. 2 is a cross-sectional view showing conductive particles according to the second embodiment of the present invention.

A conductive particle 1A shown in FIG. 2 includes a conductive particle body 11A, a plurality of flux-containing particles 12A, and a flux film 13A. In the conductive particle 1A, the conductive particle main body 11A includes a base particle 21A and a conductive portion 22A arranged outside the base particle 21A. In the conductive particles 1A, the flux-containing particles 12A are arranged outside the conductive particle body 11A. In the conductive particle 1A, the flux film 13A is arranged outside the conductive particle main body 11A. The conductive portion 22A is arranged on the surface of the substrate particle 21A and is in contact with the substrate particle 21A. In the conductive particles 1A, the flux-containing particles 12A are arranged on the surface of the conductive particle body 11A (conductive portion 22A) via the flux film 13A. In conductive particles 1A, flux-containing particles 12A are arranged on the surface of flux film 13A. The flux-containing particles 12A are not in contact with the conductive particle body 11A, but are in contact with the flux film 13A. In the conductive particles 1A, the flux film 13A is arranged on the surface of the conductive particle body 11A (conductive portion 22A) and is in contact with the conductive particle body 11A (conductive portion 22A). In the conductive particles 1A, the flux film 13A covers only the surface of the conductive particle body 11A (the surface of the conductive portion 22A). In the conductive particles 1A, the flux film 13A does not cover the surfaces of the flux-containing particles 12A. In the conductive particles 1A, the flux film 13A is arranged between the conductive particle body 11A and the flux-containing particles 12A.

The conductive particles 1 and the conductive particles 1A have different configurations of the flux-containing particles and the flux film. The flux film may or may not exist between the flux-containing particles and the conductive portion. The flux film may or may not cover the surface of the flux-containing particles.

For the conductive particles 1A, for example, the flux-containing particles 12A and the conductive particle main body 11A before the flux film 13A is arranged are used to form the flux film 13A by a flux treatment, and then the flux-containing particles 12A are applied to the flux film 13A. You can get it by attaching it.

FIG. 3 is a cross-sectional view showing conductive particles according to a third embodiment of the present invention.

A conductive particle 1B shown in FIG. 3 includes a conductive particle body 11B, a plurality of flux-containing particles 12B, and a flux film 13B. In the conductive particle 1B, the conductive particle main body 11B includes the base particle 21B and the conductive part 22B arranged outside the base particle 21B. In the conductive particles 1B, the flux-containing particles 12B are arranged outside the conductive particle body 11B. In the conductive particle 1B, the flux film 13B is arranged outside the conductive particle main body 11B. The conductive portion 22B is arranged on the surface of the substrate particle 21B and is in contact with the substrate particle 21B. In the conductive particles 1B, the flux-containing particles 12B are arranged on the surface of the conductive particle body 11B (conductive portion 22B) and are in contact with the conductive portion 22B. In the conductive particles 1B, the flux film 13B is arranged on the surface of the conductive particle body 11B (conductive portion 22B) and is in contact with the conductive particle body 11B (conductive portion 22B).

In the conductive particles 1B, the conductive portion 22B is a two-layered conductive layer. The conductive portion 22B includes a first conductive portion 22BA and a second conductive portion 22BB. In the conductive portions 22B, the first conductive portions 22BA are arranged outside the base particles 21B, and the second conductive portions 22BB are arranged outside the first conductive portions 22BA. In the conductive portion 22B, the first conductive portion 22BA is laminated on the surface of the substrate particle 21B, and the second conductive portion 22BB is laminated on the surface of the first conductive portion 22BA.

The configuration of the conductive portion is different between the conductive particles 1 and the conductive particles 1B. The conductive portion may be a single conductive layer or multiple conductive layers.

FIG. 4 is a cross-sectional view showing conductive particles according to the fourth embodiment of the present invention.

A conductive particle 1C shown in FIG. 4 includes a conductive particle body 11C, a plurality of flux-containing particles 12C, and a flux film 13C. In the conductive particle 1C, the conductive particle body 11C is composed of a base particle 21C, a conductive portion 22C arranged outside the base particle 21C, and a plurality of core substances 23C arranged outside the base particle 21C. Prepare. The conductive portion 22C covers the substrate particles 21C and the core substance 23C. By covering the core substance 23C with the conductive portion 22C, the conductive particle main body 11C has a plurality of protrusions 11Ca on the surface. The core material 23C raises the surface of the conductive portion 22C, forming a plurality of projections 11Ca.

The conductive particles 1 and 1C differ in the presence or absence of the use of a core substance and the presence or absence of protrusions on the conductive particle body. The conductive particle body may or may not have projections on the surface.

Other details of the conductive particles will be described below.

In this specification, "(meth)acrylate" indicates acrylate and methacrylate. "(Meth)acryl" indicates acryl and methacryl. "(Meth)acryloyl" indicates acryloyl and methacryloyl.

The particle diameter of the conductive particles is preferably 1 μm or more, more preferably 10 μm or more, and preferably 50 μm or less, more preferably 40 μm or less. When the particle diameter of the conductive particles is the lower limit or more and the upper limit or less, when the electrodes are connected using the conductive particles, the contact area between the conductive particles and the electrodes is sufficiently large, In addition, it becomes difficult to form agglomerated conductive particles when forming the conductive portion. Also, the distance between the electrodes connected via the conductive particle main body does not become too large, and the conductive portion is less likely to peel off from the surface of the base particle.

The particle diameter of the conductive particle main body is preferably 1 µm or more, more preferably 10 µm or more, and preferably 50 µm or less, more preferably 40 µm or less. When the particle diameter of the conductive particle body is at least the lower limit and at most the upper limit, when the electrodes are connected using the conductive particle, the contact area between the conductive particle body and the electrode is sufficiently large. In addition, it becomes difficult to form an aggregated conductive particle main body when forming the conductive portion. Also, the distance between the electrodes connected via the conductive particle main body does not become too large, and the conductive portion is less likely to peel off from the surface of the base particle.

The particle size of the conductive particles and the conductive particle main body is preferably an average particle size, and the average particle size indicates a number average particle size. The particle diameters of the conductive particles and the conductive particle main body are, for example, 50 arbitrary conductive particles are observed with an electron microscope or an optical microscope, and the average particle diameter of each conductive particle and each conductive particle main body. It can be obtained by calculating the value or performing laser diffraction particle size distribution measurement.

From the viewpoint of more effectively increasing the reliability of conduction between electrodes, the coefficient of variation (CV value) of the particle size of the conductive particles and the conductive particle main body is preferably 10% or less, more preferably 5%. It is below.

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

CV value (%) = (ρ/Dn) × 100
ρ: standard deviation of the particle size of the conductive particles or the main body of the conductive particles Dn: the average value of the particle size of the conductive particles or the main body of the conductive particles

The shape of the conductive particles and the main body of the conductive particles is not particularly limited. The conductive particles and the conductive particle main body may have a spherical shape, a shape other than a spherical shape, or a flat shape.

<Base material particles>
Examples of the substrate particles include resin particles, inorganic particles other than metal particles, organic-inorganic hybrid particles, and metal particles. The substrate particles are preferably substrate particles other than metal particles, and more preferably resin particles, inorganic particles other than metal particles, or organic-inorganic hybrid particles. The substrate particles may be core-shell particles comprising a core and a shell arranged on the surface of the core. The core may be an organic core and the shell may be an inorganic shell.

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, and phenol formaldehyde. Resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenolic resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polysulfone, polyphenylene oxide, polyacetal, polyimide, Examples include polyamideimide, polyetheretherketone, polyethersulfone, and divinylbenzene polymer. The divinylbenzene polymer may be a divinylbenzene copolymer. Examples of the divinylbenzene copolymer and the like include a divinylbenzene-styrene copolymer and a divinylbenzene-(meth)acrylate copolymer. Since the hardness of the resin particles can be easily controlled within a suitable range, the material of the resin particles is a polymer obtained by polymerizing one or more polymerizable monomers having an ethylenically unsaturated group. is preferred.

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-crosslinking monomer. and crosslinkable monomers.

Examples of the non-crosslinkable monomers include styrene and styrene-based monomers such as α-methylstyrene; carboxyl group-containing monomers such as (meth)acrylic acid, maleic acid, and maleic anhydride; 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 ( Alkyl (meth)acrylate compounds such as meth)acrylate and isobornyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate, glycerol (meth)acrylate, polyoxyethylene (meth)acrylate, and glycidyl (meth)acrylate, etc. Oxygen atom-containing (meth)acrylate compounds; nitrile-containing monomers such as (meth)acrylonitrile; vinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether, and propyl vinyl ether; vinyl acetate, vinyl butyrate, vinyl laurate, and vinyl stearate, etc. acid vinyl ester compounds of; unsaturated hydrocarbons such as ethylene, propylene, isoprene, and butadiene; halogens such as trifluoromethyl (meth)acrylate, pentafluoroethyl (meth)acrylate, vinyl chloride, vinyl fluoride, and chlorostyrene A contained monomer etc. are mentioned.

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 Polyfunctional (meth)acrylate compounds such as 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 γ-(meth)acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, vinyltrimethoxysilane, etc. and silane-containing monomers. From the viewpoint of maintaining the shape of the flux-containing particles even at the glass transition temperature of the resin particles, the crosslinkable monomers include (poly)ethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, penta Erythritol tetra(meth)acrylate or dipentaerythritol poly(meth)acrylate is preferred.

The resin particles can be obtained by polymerizing the polymerizable monomer having the ethylenically unsaturated group by a known method. Examples of this method include a method of suspension polymerization in the presence of a radical polymerization initiator, and a method of polymerizing by swelling a monomer together with a radical polymerization initiator using uncrosslinked seed particles.

When the substrate particles are inorganic particles excluding metals or organic-inorganic hybrid particles, examples of inorganic substances for forming the substrate particles include silica, alumina, barium titanate, zirconia, and carbon black. Preferably, the inorganic substance is not a metal. The particles formed of silica can be obtained, for example, by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups to form crosslinked polymer particles, followed by firing as necessary. particles that can be used. Examples of the organic-inorganic hybrid particles include organic-inorganic hybrid particles formed from a crosslinked alkoxysilyl polymer and an acrylic resin.

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. It is preferred that the core is an organic core. Preferably, the shell is an inorganic shell. From the viewpoint of effectively reducing the connection resistance between electrodes, the substrate particles are preferably organic-inorganic hybrid particles having an organic core and an inorganic shell disposed on the surface of the organic core.

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

Examples of the material for the inorganic shell include the inorganic substances listed above as the material for the substrate particles. The inorganic shell material is preferably silica. The inorganic shell is preferably formed by forming a metal alkoxide into a shell-like material on the surface of the core by a sol-gel method, and then firing the shell-like material. The metal alkoxide is preferably silane alkoxide. The inorganic shell is preferably made of silane alkoxide.

When the substrate particles are metal particles, examples of metals that are materials of the metal particles include silver, copper, nickel, silicon, gold, and titanium.

The particle diameter of the substrate particles is preferably 0.5 μm or more, more preferably 9.5 μm or more, and preferably 49.95 μm or less, more preferably 39.95 μm or less. When the particle size of the substrate particles is equal to or more than the lower limit and equal to or less than the upper limit, small conductive particles can be obtained even when the distance between the electrodes is small and the thickness of the conductive portion is increased. Furthermore, it becomes difficult to aggregate when forming the conductive portion on the surface of the substrate particles, and it becomes difficult to form aggregated conductive particles.

The shape of the substrate particles is not particularly limited. The shape of the substrate particles may be spherical, may be other than spherical, or may be flat.

The particle size of the substrate particles is preferably the average particle size, and the average particle size indicates the number average particle size. The particle size of the substrate particles is determined using a particle size distribution analyzer or the like. The particle diameter of the substrate particles is preferably determined by observing 50 arbitrary substrate particles with an electron microscope or an optical microscope and calculating the average value. When measuring the particle size of the substrate particles of the conductive particles, it can be measured, for example, as follows.

"Technovit 4000" manufactured by Kulzer is added so that the content of the conductive particles is 30% by weight, and dispersed to prepare an embedded resin body for inspection containing the conductive particles. Using an ion milling device (“IM4000” manufactured by Hitachi High-Technologies Corporation), a cross section of the conductive particles is cut out so as to pass through the vicinity of the center of the conductive particles dispersed in the embedded resin body for inspection. Then, using a field emission scanning electron microscope (FE-SEM), set the image magnification to 25000 times, randomly select 50 conductive particles, and observe the base particles of each conductive particle. do. The particle diameter of the base material particles in each conductive particle is measured, and the arithmetic mean is taken as the particle size of the base material particles.

<Core substance and protrusion>
The conductive particle body preferably has projections on the outer surface of the conductive portion. It is preferable that the protrusion is plural. In general, an oxide film is often formed on the surface of the electrode that contacts the main body of the conductive particles. When a conductive particle body having projections on the surface of the conductive portion is used, the oxide film can be effectively removed by the projections at the time of conductive connection. As a result, the electrode and the conductive portion can be brought into contact with each other more reliably, the contact area between the conductive particle body and the electrode can be sufficiently increased, and the connection resistance can be more effectively reduced. Furthermore, when the conductive particles are dispersed in a binder and used as a conductive material, the protrusions of the conductive particle bodies can more effectively eliminate the binder between the conductive particle bodies and the electrode. Therefore, the contact area between the conductive particle body and the electrode can be sufficiently increased, and the connection resistance can be further effectively reduced. The conductive particle main body preferably has a core substance on the outside of the substrate particles. The conductive particle body preferably has a core substance on the surface of the substrate particle.

Examples of methods for forming projections on the surface of the conductive particle body include the following methods. A method of forming a conductive portion by electroless plating after adhering a core substance to the surface of a substrate particle. A method of forming a conductive portion on the surface of a substrate particle by electroless plating, adhering a core substance, and further forming a conductive portion by electroless plating. A method of forming a conductive portion on the surface of a substrate particle by electroless plating, and then forming projections having the same composition as the conductive portion by electroless plating.

As a method for attaching the core substance to the surface of the substrate particles, for example, the core substance is added to the dispersion liquid of the substrate particles, and the core substance is accumulated on the surface of the substrate particles by, for example, Van der Waals force. and a method of adding the core substance to a container containing the base particles and attaching the core substance to the surface of the base particles by mechanical action such as rotation of the container. Among them, the method of accumulating and attaching the core substance to the surface of the substrate particles in the dispersion liquid is preferable because the amount of the core substance to be adhered can be easily controlled.

The conductive particles may have a first conductive portion on the outside of the base particles and a second conductive portion on the outside of the first conductive portion. In this case, a core substance may be adhered to the surface of the first conductive portion. The core substance is preferably covered with the second conductive portion. The short diameter of the core substance is preferably 0.05 μm or more and preferably 0.5 μm or less. The conductive particles form the first conductive portion on the surface of the substrate particle, then attach the core substance on the surface of the first conductive portion, and then the surface of the first conductive portion and the core substance It is preferably obtained by forming a second conductive portion thereon.

　Conductive substances and non-conductive substances can be mentioned as substances that constitute the core substance. Examples of the conductive substance include metals, metal oxides, conductive nonmetals such as graphite, and conductive polymers. Polyacetylene etc. are mentioned as said conductive polymer. Silica, alumina, zirconia, and the like are mentioned as the non-conductive substance. From the standpoint of enhancing conduction reliability, the substance constituting the core substance is preferably a metal. The core substance is preferably metal particles.

Examples of the above metals include metals such as gold, silver, copper, platinum, zinc, iron, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium and cadmium, and tin-lead. alloys, tin-copper alloys, tin-silver alloys, tin-lead-silver alloys, and alloys composed of two or more metals such as tungsten carbide. Among them, nickel, copper, silver or gold is preferable. The metal forming the core substance may be the same as or different from the metal forming the conductive portion (conductive layer).

The shape of the core substance is not particularly limited. The shape of the core substance is preferably massive. The core substance includes, for example, particulate lumps, agglomerates in which a plurality of microparticles are aggregated, irregular lumps, and the like.

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

<Conductive part>
In the present invention, the conductive particles have conductive portions on their surfaces. The conductive portion is arranged on the surface of the substrate particle.

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

From the viewpoint of further enhancing conduction reliability, the conductive portion preferably contains tin, nickel, copper or gold, more preferably tin or nickel, and still more preferably tin.

From the viewpoint of further improving conduction reliability, the conductive portion preferably contains tin as a main metal. From the viewpoint of further improving conduction reliability, the tin content is preferably 10% by weight or more in 100% by weight of the conductive portion. From the viewpoint of further improving conduction reliability, the content of tin in 100% by weight of the conductive portion is preferably 15% by weight or more, more preferably 20% by weight or more, further preferably 25% by weight or more, and particularly preferably 25% by weight or more. is 30% by weight or more. The content of tin in 100% by weight of the conductive portion may be 100% by weight (total amount).

The conductive portion may be formed of one layer. The conductive portion may be formed of a plurality of layers. That is, the conductive portion may have a laminated structure of two or more layers. When the conductive portion is formed of a plurality of layers, the metal constituting the outermost layer is preferably tin, nickel or gold, more preferably tin or nickel, and tin. More preferred. When the metal forming the outermost layer is one of these preferred metals, the connection resistance between the electrodes is even lower. Further, when the metal forming the outermost layer is gold, the corrosion resistance is further enhanced.

Within 100% of the total surface area of the substrate particles, the area (coverage) of the conductive portion is preferably 80% or more, more preferably 90% or more. The upper limit of the coverage rate is not particularly limited. The coverage may be 99% or less. When the coverage is equal to or more than the lower limit and equal to or less than the upper limit, it is possible to further effectively improve the conduction reliability when the electrodes are electrically connected.

The thickness of the conductive portion is preferably 0.005 μm or more, more preferably 0.01 μm or more, and preferably 10 μm or less, more preferably 1 μm or less, and even more preferably 0.5 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 reliability of conduction is further effectively improved, and the conductive particles do not become too hard, so that the conductive particles can be electrically conductive when connecting between electrodes. Particles can be sufficiently deformed.

When the conductive portion is formed of a plurality of layers, the thickness of the conductive portion in the outermost layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, and preferably 0.5 μm or less, and more preferably. is 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 is uniform, the corrosion resistance is sufficiently high, and the connection resistance between electrodes is sufficiently low. can do.

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

The method of forming the conductive portion on the surface of the substrate particles is not particularly limited. Methods for forming the conductive portion include, for example, a method by electroless plating, a method by electroplating, a method by physical collision, a method by mechanochemical reaction, a method by physical vapor deposition or physical adsorption, and metal powder or Examples thereof include a method of coating the surface of the substrate particles with a paste containing a metal powder and a binder. The method of forming the conductive portion is preferably electroless plating, electroplating, or a method using physical collision. Methods such as vacuum deposition, ion plating, and ion sputtering can be used as the method by physical vapor deposition. Also, in the method using physical collision, for example, a sheeter composer (manufactured by Tokuju Kosakusho Co., Ltd.) or the like is used.

<Flux-containing particles>
The conductive particles comprise flux-containing particles. The flux-containing particles are arranged outside the conductive particle body. The flux-containing particles are arranged on the surface of the conductive particle body. The flux-containing particles are arranged on the surface of the conductive portion. The flux-containing particles may be arranged on the surface of the conductive particle body or the conductive portion via a flux film or the like. The flux-containing particles may be in contact with the surface of the conductive particle body, or may not be in contact with the surface of the conductive particle body. The flux-containing particles may be in contact with the surface of the conductive portion, or may not be in contact with the surface of the conductive portion.

The flux-containing particles preferably contain a particle body and flux.

Examples of the particle main body include inorganic particles other than metal particles, resin particles, organic-inorganic hybrid particles, metal particles, and the like. The particle bodies are preferably inorganic particles other than metal particles or resin particles, and more preferably resin particles.

Examples of inorganic particles other than the metal particles include silica, alumina, and titania. Porous silica etc. are mentioned as said silica.

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, and phenol formaldehyde. Resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenolic resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polysulfone, polyphenylene oxide, polyacetal, polyimide, Examples include polyamideimide, polyetheretherketone, polyethersulfone, and divinylbenzene polymer. The divinylbenzene polymer may be a divinylbenzene copolymer. Examples of the divinylbenzene copolymer and the like include a divinylbenzene-styrene copolymer and a divinylbenzene-(meth)acrylate copolymer. Since the hardness of the resin particles can be easily controlled within a suitable range, the material of the resin particles preferably contains a polymerizable monomer. More preferably, it is a polymer obtained by polymerizing two or more kinds.

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 Polyfunctional (meth)acrylate compounds such as 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 γ-(meth)acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, vinyltrimethoxysilane, etc. and silane-containing monomers.

The glass transition temperature of the homopolymer of the polymerizable monomer is preferably 40° C. or higher, more preferably 50° C. or higher, still more preferably 80° C. or higher, and preferably 250° C. or lower, more preferably 230° C. or lower. , and more preferably 200° C. or less. When the glass transition temperature of the homopolymer of the polymerizable monomer is above the lower limit and below the upper limit, the flux gradually leaks out from the flux-containing particles due to heating and pressurization during conductive connection. As a result, the oxide film on the surface of the conductive particles and the surface of the electrode can be removed more effectively, and the reliability of conduction is more effectively improved when the electrodes are electrically connected. be able to. Among the polymerizable monomers of the material of the resin particles, the glass transition temperature of the homopolymer of the polymerizable monomer having the highest content on a weight basis is preferably at least the above lower limit, and at most the above upper limit. Preferably.

The above flux is not particularly limited. Examples of the flux include zinc chloride, mixtures of zinc chloride and inorganic halides, mixtures of zinc chloride and inorganic acids, phosphoric acid, phosphoric acid derivatives, organic halides, hydrazine, amine compounds, molten salts, organic acids and pine resin and the like. Only one kind of the above flux may be used, or two or more kinds thereof may be used in combination.

Examples of the amine compounds include cyclohexylamine, dicyclohexylamine, benzylamine, benzhydrylamine, imidazole, benzimidazole, phenylimidazole, carboxybenzimidazole, benzotriazole, carboxybenzotriazole, and the like.

Examples of the molten salt include ammonium chloride.

From the standpoint of more effectively enhancing conduction reliability, the flux is preferably an organic acid or rosin, more preferably rosin.

The above organic acid is preferably an organic acid having two or more carboxyl groups. Examples of the organic acid having two or more carboxyl groups include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid.

The above pine resin is a rosin whose main component is abietic acid. Examples of the rosins include abietic acid and acryl-modified rosins. From the standpoint of more effectively enhancing conduction reliability, the rosin is more preferably abietic acid.

The melting point (activation temperature) of the flux is preferably 10°C or higher, more preferably 50°C or higher, more preferably 70°C or higher, still more preferably 80°C or higher, and preferably 200°C or lower, more preferably 190°C. Below, it is more preferably 160° C. or lower, still more preferably 150° C. or lower, and even more preferably 140° C. or lower. When the melting point of the flux is equal to or higher than the lower limit and equal to or lower than the upper limit, the flux effect is exhibited more effectively, and the conductive particles are arranged on the electrode even more efficiently. The melting point (activation temperature) of the flux is preferably 80° C. or higher and 190° C. or lower, and particularly preferably 80° C. or higher and 140° C. or lower.

Examples of the above-mentioned fluxes having a melting point (activation temperature) of 80° C. or more and 190° C. or less include succinic acid (melting point 186° C.), glutaric acid (melting point 96° C.), adipic acid (melting point 152° C.), pimelic acid (melting point 104° C.). °C), dicarboxylic acids such as suberic acid (melting point 142°C), benzoic acid (melting point 122°C), and malic acid (melting point 130°C).

Also, the boiling point of the flux is preferably 300°C or lower.

From the viewpoint of enhancing the effect of the flux, in the conductive particles according to the present invention, the particle diameter of the flux-containing particles is preferably 100 nm or more, more preferably 200 nm or more, still more preferably 350 nm or more, and preferably 800 nm or less. , more preferably 500 nm or less, and still more preferably 400 nm or less.

The particle size of the flux-containing particles is the average particle size, and the average particle size indicates the volume average particle size. The particle size of the flux-containing particles is determined using a particle size distribution analyzer or the like.

The ratio of the particle size of the conductive particles to the particle size of the flux-containing particles (particle size of conductive particles/particle size of flux-containing particles) is preferably 3 or more, more preferably 6 or more, and still more preferably 16. or more, preferably 500 or less, more preferably 150 or less, even more preferably 100 or less, and particularly preferably 70 or less. When the ratio (particle diameter of the conductive particles/particle diameter of the flux-containing particles) is equal to or more than the lower limit and equal to or less than the upper limit, insulation reliability and conduction reliability are improved when the electrodes are electrically connected. can be enhanced more effectively.

The ratio of the particle diameter of the conductive particle main body to the particle diameter of the flux-containing particle (particle diameter of the conductive particle main body/particle diameter of the flux-containing particle) is preferably 3 or more, more preferably 6 or more, and still more preferably. is 16 or more, preferably 500 or less, more preferably 150 or less, still more preferably 100 or less, and particularly preferably 60 or less. When the above ratio (particle diameter of the conductive particle main body/particle diameter of the flux-containing particles) is equal to or more than the lower limit and equal to or less than the upper limit, insulation reliability and conduction reliability are improved when the electrodes are electrically connected. can be enhanced more effectively.

From the viewpoint of exhibiting the effect of the present invention more effectively, the coefficient of variation (CV value) of the particle diameter of the flux-containing particles is preferably 20% or less.

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

CV value (%) = (ρ/Dn) × 100
ρ: standard deviation of particle size of flux-containing particles Dn: average value of particle size of flux-containing particles

The shape of the flux-containing particles is not particularly limited. The flux-containing particles may have a spherical shape, a shape other than a spherical shape, or a flat shape. From the viewpoint of exhibiting the effects of the present invention more effectively, the flux-containing particles are preferably spherical.

From the viewpoint of exhibiting the effect of the present invention more effectively, when the particle body of the flux-containing particles is a resin particle, the glass transition of the homopolymer of the polymerizable monomer that is the material of the resin particle At the temperature, the flux-containing particles preferably maintain their particulate form.

The flux-containing particles preferably do not have a breaking point in the compression-displacement curve when a maximum test load of 3.3 mN is applied to the flux-containing particles for 10 seconds. In this case, the flux gradually leaks from the flux-containing particles due to heating and pressurization during conductive connection, so that the oxide film on the surface of the conductive particles and the surface of the electrode can be removed more effectively. In addition, when the electrodes are electrically connected, the reliability of conduction can be improved more effectively. Specifically, using a microcompression tester, the flux-containing particles are compressed at 25° C. with a smooth indenter end face of a cylinder (diameter 50 μm, made of diamond) under the conditions of applying a maximum test load of 3.3 mN for 10 seconds. do. The load value (N) and compression displacement (mm) at this time are measured to prepare a compression-displacement curve. As the microcompression tester, for example, "ENT-NEXUS" manufactured by Elionix Co., Ltd. is used.

In addition, from the viewpoint of exhibiting the effects of the present invention more effectively, the flux-containing particles are preferably not microcapsules encapsulating flux. The particle body in the flux-containing particles may be particles having a porous structure. The porous structure means a structure having a plurality of pores (pores).

The distance from the surface of the flux-containing particles toward the center is divided into three equal parts, and the flux-containing particles are divided into three parts: a surface part, a center part, and an intermediate part between the surface part and the center part. In this case, the flux-containing particles may contain the flux in the surface portion, the intermediate portion, or the central portion. The flux-containing particles preferably contain flux in the surface portion, more preferably in the surface portion and the intermediate portion, and even more preferably in the surface portion, the intermediate portion, and the central portion. . In this case, the flux gradually leaks from the flux-containing particles due to heating and pressurization during conductive connection, so that the oxide film on the surface of the conductive particles and the surface of the electrode can be removed more effectively. In addition, when the electrodes are electrically connected, the reliability of conduction and the reliability of insulation can be improved more effectively. Also, the flux-containing particles may contain flux in the intermediate portion and the central portion.

In addition, from the viewpoint of effectively improving conduction reliability and insulation reliability, the flux-containing particles preferably contain flux in the outermost surface portion having a thickness of 10 nm from the surface to the center of the flux-containing particles.

From the viewpoint of improving conduction reliability, when a conductive particle-containing liquid obtained by adding 3 parts by weight of the above conductive particles to 100 parts by weight of ethanol was subjected to ultrasonic treatment for 5 minutes at 20 ° C. and 40 kHz, the following It is preferable that the residual rate of the flux-containing particles determined by the formula (1) is 99% or less.

The coverage rate by the flux-containing particles means the total area of the portion where the flux-containing particles are arranged in 100% of the total surface area of the conductive particle body. The coverage with the flux-containing particles is obtained by observing the conductive particles with an electron microscope or an optical microscope and calculating the percentage of the surface area of the portion where the flux-containing particles are arranged to the projected area of the main body of the conductive particles. Desired. The coverage with the flux-containing particles is preferably determined by observing 20 arbitrary conductive particles with a scanning electron microscope (SEM), and measuring the surface area of the portion where the flux-containing particles are arranged, of the conductive particle body. It is obtained by calculating the average percentage of the projected area.

From the viewpoint of improving conduction reliability, the residual rate of the flux-containing particles is preferably 90% or less, more preferably 70% or less, even more preferably 65% or less, and particularly preferably 60% or less. The lower limit of the residual rate of the flux-containing particles is not particularly limited. The residual rate of the flux-containing particles may be 0%.

Methods for adjusting the residual rate of the flux-containing particles to the preferred range include a method of using particles made of a material with low adhesiveness as the particle body of the flux-containing particles, and a method of using particles with a high flux content as flux-containing particles. A method of using it as a particle body of particles, and the like.

Examples of the method for incorporating the flux into the particle body (method for forming the flux-containing particles) include the following methods. A method in which the particles are dispersed in a solvent containing a low concentration of flux to adsorb the flux components. A method in which an organic solvent containing a high concentration of flux components is sprayed onto the particle body to adhere the flux. A method in which flux is added to the solvent during particle production to contain the flux inside the particle body. From the viewpoint of improving conduction reliability, the method of adding the flux to the particle body is preferably a method of dispersing the particle body in a solvent containing a low concentration of flux to adsorb the flux component.

Examples of methods for disposing the flux-containing particles on the surface of the conductive particle body include chemical methods and physical or mechanical methods. Examples of the chemical method include an interfacial polymerization method, a suspension polymerization method in the presence of particles, an emulsion polymerization method, and the like. Examples of the physical or mechanical methods include spray drying, hybridization, electrostatic adhesion, atomization, dipping and vacuum deposition. From the viewpoint of more effectively improving the insulation reliability and conduction reliability when the electrodes are electrically connected, the method of arranging the flux-containing particles on the surface of the conductive particle body is an electrostatic Adhesive methods are preferred.

The outer surface of the conductive portion and the outer surface of the flux-containing particles may each be coated with a compound having a reactive functional group. The outer surface of the conductive portion and the outer surface of the flux-containing particles may not be directly chemically bonded, but may be indirectly chemically bonded by a compound having a reactive functional group. After introducing carboxyl groups into the outer surface of the conductive portion, the carboxyl groups may be chemically bonded to the functional groups on the outer surface of the flux-containing particles via a polymer electrolyte such as polyethyleneimine.

From the viewpoint of exhibiting the effects of the present invention more effectively, the content of the flux-containing particles in 100% by weight of the conductive particles is preferably 1% by weight or more, more preferably 1.5% by weight or more. , more preferably 2% by weight or more, still more preferably 2.5% by weight or more, and particularly preferably 3% by weight or more.

The sum of the flux content in the flux-containing particles and the flux content in the flux film in 100% by weight of the conductive particles is preferably 1% by weight or more, more preferably 1.5% by weight or more, More preferably 2% by weight or more, more preferably 3% by weight or more, and particularly preferably 10% by weight or more. When the total flux content is at least the above lower limit, the effects of the present invention can be exhibited more effectively.

The flux content in the flux-containing particles is preferably 5 wt% or more, more preferably 100 wt% in total of the flux content in the flux-containing particles and the flux content in the flux film described later. It is 10% by weight or more, more preferably 15% by weight or more, still more preferably 20% by weight or more, and particularly preferably 50% by weight or more. When the flux content in the flux-containing particles is at least the above lower limit, the effects of the present invention can be exhibited more effectively.

<Flux film>
The conductive particles comprise a flux film. The flux film is arranged outside the conductive particle body. The flux film is arranged outside the conductive portion. The flux film is arranged on the surface of the conductive particle body. The flux film is arranged on the surface of the conductive portion. The flux film may be arranged outside the flux-containing particles, or may not be arranged outside the flux-containing particles. The flux film may be arranged on the surfaces of the flux-containing particles, or may not be arranged on the surfaces of the flux-containing particles.

The flux in the flux film includes the above-mentioned flux. The flux in the flux film may be the same as or different from the flux in the flux-containing particles.

Within 100% of the total surface area of the conductive particle body, the area of the flux film (coverage by the flux film) is preferably 40% or more, more preferably 50% or more. The upper limit of the coverage rate is not particularly limited. The coverage may be 99% or less. When the coverage is the lower limit or more and the upper limit or less, the oxide film on the surface of the conductive particles and the surface of the electrode can be removed more effectively, and the electrodes are electrically connected. In this case, the conduction reliability can be enhanced more effectively.

The thickness of the flux film is preferably 0.5 nm or more, more preferably 1 nm or more, and preferably 100 nm or less, more preferably 50 nm or less, and even more preferably 25 nm or less. When the thickness of the flux film is equal to or more than the lower limit and equal to or less than the upper limit, the conduction reliability is more effectively improved, and the conductive particles do not become too hard, so that the electrodes can be electrically conductive at the time of connection. Particles can be sufficiently deformed.

A physical or mechanical method can be used as a method for arranging the flux film on the surface of the conductive particle body. Examples of the physical or mechanical methods include spray drying, hybridization, electrostatic adhesion, atomization, dipping and vacuum deposition. From the viewpoint of more effectively improving the insulation reliability and conduction reliability when the electrodes are electrically connected, dipping is the method for disposing the flux film on the surface of the conductive particle body. is preferred.

(Conductive material)
The conductive material according to the present invention contains the conductive particles described above and a binder resin. The conductive particles are preferably dispersed in a binder resin for use, and preferably dispersed in a binder resin for use as a conductive material. The conductive material is preferably an anisotropic conductive material. The conductive material is preferably used for electrical connection between electrodes. The conductive material is preferably a conductive material for circuit connection. Since the above-described conductive particles are used in the conductive material, the reliability of insulation and reliability of conduction between electrodes can be further improved.

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 photocurable components and thermosetting components. The photocurable component preferably contains a photocurable compound and a photopolymerization initiator. The thermosetting component preferably contains a thermosetting compound and a thermosetting agent.

Examples of the binder resin include vinyl resins, thermoplastic resins, curable resins, thermoplastic block copolymers and elastomers. Only one kind of the binder resin may be used, or two or more kinds thereof may be used in combination.

Examples of the vinyl resin include vinyl acetate resin, acrylic resin and styrene resin. Examples of the thermoplastic resins include polyolefin resins, ethylene-vinyl acetate copolymers and polyamide resins. 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 copolymers include styrene-butadiene-styrene block copolymers, styrene-isoprene-styrene block copolymers, hydrogenated products of styrene-butadiene-styrene block copolymers, and styrene-isoprene. - hydrogenated products of styrene block copolymers; Examples of the elastomer include styrene-butadiene copolymer rubber and acrylonitrile-styrene block copolymer rubber.

In addition to the conductive particles and the binder resin, the conductive material includes, for example, a filler, an extender, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a coloring agent, an antioxidant, a heat stabilizer, and a light stabilizer. It may contain various additives such as agents, UV absorbers, lubricants, antistatic agents and flame retardants.

The method for dispersing the conductive particles in the binder resin is not particularly limited, and a conventionally known dispersing method can be used. Examples of the method for dispersing the conductive particles in the binder resin include the following methods. A method of adding the conductive particles to the binder resin and then kneading and dispersing the mixture with a planetary mixer or the like. A method in which the conductive particles are uniformly dispersed in water or an organic solvent using a homogenizer or the like, then added to the binder resin, kneaded with a planetary mixer or the like, and dispersed. A method of diluting the binder resin with water, an organic solvent, or the like, adding the conductive particles, and kneading and dispersing the mixture with a planetary mixer or the like.

The viscosity (η25) of the conductive material 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 conductive material at 25 ° C. is at least the lower limit and at most the upper limit, the insulation reliability between the electrodes can be more effectively improved, and the conduction reliability between the electrodes can be more effectively improved. can be increased to The viscosity (η25) can be appropriately adjusted depending on the types and amounts of ingredients to be blended.

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.

The conductive material according to the present invention can be used as a conductive paste, a conductive film, and the like. When the conductive material according to the present invention is a conductive film, a film containing no 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.

The content of the binder resin in 100% by weight of the conductive material is preferably 10% by weight or more, more preferably 30% by weight or more, still more preferably 50% by weight or more, and particularly preferably 70% by weight or more. is 99.99% by weight or less, more preferably 99.9% by weight or less. When the content of the binder resin is the lower limit or more and the upper limit or less, the conductive particles are efficiently arranged between the electrodes, and the connection reliability of the connection target members connected by the conductive material is further improved. can be done.

The content of the conductive particles in 100% by weight of the conductive material is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, and preferably 80% by weight or less, more preferably 60% by weight. %, 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 conductive particles is equal to or more than the lower limit and equal to or less than the upper limit, reliability of electrical connection and reliability of insulation between electrodes can be further enhanced.

(connection structure)
A connection structure according to the present invention includes a first connection object member having a first electrode on the surface, a second connection object member having a second electrode on the surface, the first connection object member, and a connecting portion connecting the second connection target member. In the bonded structure according to the present invention, the material of the connecting portion contains the above-described conductive particles. In the connection structure according to the present invention, the first electrode and the second electrode are electrically connected by the conductive particle body. The material of the connecting portion is preferably conductive particles or a conductive material containing the conductive particles and a binder resin.

The connection structure includes a step of disposing the conductive particles or the conductive material between the first member to be connected and the second member to be connected, and a step of electrically connecting by thermocompression bonding. can be obtained through It is preferable that the flux-containing particles are detached from the conductive particles during the thermocompression bonding. In particular, it is preferable that the flux-containing particles between the conductive particle body and the electrode are detached from the conductive particles.

FIG. 5 is a cross-sectional view schematically showing a connection structure using conductive particles according to the first embodiment of the present invention.

A connection structure 81 shown in FIG. 5 includes a first connection target member 82, a second connection target member 83, and a connection portion that connects the first connection target member 82 and the second connection target member 83. 84. The connecting portion 84 is made of a conductive material containing the conductive particles 1 . The connecting portion 84 is preferably formed by curing a conductive material containing a plurality of conductive particles 1 . In addition, in FIG. 5, the conductive particles 1 are schematically shown for convenience of illustration. Instead of the conductive particles 1, conductive particles 1A, conductive particles 1B, or conductive particles 1C may be used.

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 electrode 82a and the second electrode 83a are electrically connected by the conductive particle body 11 of the one or more conductive particles 1 . Therefore, the first connection object member 82 and the second connection object member 83 are electrically connected by the conductive particle body 11 of the conductive particle 1 .

The manufacturing method of the connection structure is not particularly limited. As an example of a method for manufacturing a connected structure, the conductive material is arranged between a first member to be connected and a second member to be connected to obtain a laminate, and then the laminate is heated and pressurized. methods and the like. The pressure of the thermocompression bonding is preferably 40 MPa or higher, more preferably 60 MPa or higher, and preferably 90 MPa or lower, more preferably 70 MPa or lower. The heating temperature for the thermocompression bonding is preferably 80° C. or higher, more preferably 100° C. or higher, and preferably 140° C. or lower, more preferably 120° C. or lower. When the pressure and heating temperature of the thermocompression bonding are equal to or higher than the lower limit and equal to or lower than the upper limit, the flux-containing particles and the flux film can be easily removed from the surface of the conductive particles at the time of conductive connection. can further improve the reliability of electrical continuity. In addition, since the flux gradually leaks from the flux-containing particles when the flux-containing particles are desorbed, the oxide film on the surface of the conductive particles and the surface of the electrode can be removed more effectively. In addition, when the electrodes are electrically connected, the reliability of conduction can be improved more effectively. Furthermore, since the flux gradually leaks from the flux-containing particles even after the conductive connection, the oxide film on the surfaces of the conductive particles and the electrodes after the conductive connection can be effectively removed, and the electrodes are separated. When electrically connected, the conduction reliability can be enhanced more effectively.

When heating and pressurizing the laminate, the flux-containing particles and the flux film existing between the conductive particles and the first electrode and the second electrode can be eliminated. . For example, during the heating and pressurization, the flux-containing particles and the flux film existing between the conductive particles and the first electrode and the second electrode become conductive. It desorbs from the surface of the particle. During the heating and pressurization, part of the flux-containing particles and the flux film are detached from the surfaces of the conductive particles, and the surfaces (conductive portions) of the conductive particles are partially exposed. I have something to do. The portion where the surface (conductive portion) of the conductive particle body is exposed contacts the first electrode and the second electrode, so that the first electrode and the second electrode are connected via the conductive particle body. The electrodes can be electrically connected.

The first member to be connected and the second member to be connected are not particularly limited. Specifically, 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 resin films, printed circuit boards, flexible Examples include electronic components such as circuit boards such as printed boards, flexible flat cables, rigid flexible boards, glass epoxy boards and glass boards. The first member to be connected and the second member to be connected are preferably electronic components.

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 member to be connected is a flexible printed circuit board, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, a silver electrode or a copper electrode. When the member to be connected is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode, a silver electrode, or a tungsten electrode. When the electrode is an aluminum electrode, it may be an electrode made of only aluminum, or an electrode 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 elements include Sn, Al and Ga.

The present invention will be specifically described below with reference to examples and comparative examples. The invention is not limited only to the following examples.

"I prepared the following materials."

flux:
Rosin-based flux ("KR-612" manufactured by Arakawa Chemical Industries, softening point: 82 ° C.)
Adipate benzylamine salt (melting point: 171°C)

(Example 1)
(1) Production of conductive particle body (production of substrate particles)
Resin particles (average particle diameter: 20 μm) formed from a copolymer of tetramethylolmethane tetraacrylate and divinylbenzene were prepared as substrate particles. After dispersing 10 parts by weight of the base particles in 100 parts by weight of an alkaline solution containing 5% by weight of the palladium catalyst solution using an ultrasonic disperser, the solution was filtered to obtain the base particles. Next, the substrate particles were added to 100 parts by weight of a solution containing 1% by weight of dimethylamine borane to activate the surfaces of the substrate particles. After thoroughly washing the surface-activated substrate particles with water, they were added to 500 parts by weight of distilled water and dispersed to obtain a dispersion liquid (A). Next, 1 g of a nickel particle slurry (average particle size: 100 nm) was added to the dispersion (A) over 3 minutes to obtain a suspension (A) containing substrate particles to which the core substance was attached.

(Formation of conductive portion)
A nickel plating solution (pH 8.5) containing 0.35 mol/L nickel sulfate, 1.38 mol/L dimethylamine borane, and 0.5 mol/L sodium citrate was prepared. While the suspension (A) was stirred at 70° C., the nickel plating solution was gradually dropped into the suspension (A) to perform electroless nickel plating. After that, the particles were taken out by filtration, washed with water, and dried to form a first conductive portion (nickel-boron layer) on the surface of the substrate particles. Next, a tin plating solution was prepared by adjusting a mixed solution containing 15 g/L of tin sulfate, 45 g/L of ethylenediaminetetraacetic acid, and 1.5 g/L of phosphinic acid to pH 8.5 with sodium hydroxide. A reducing solution was prepared by adjusting the pH of a solution containing 5 g/L of sodium borohydride to 10.0 with sodium hydroxide. The tin plating solution was gradually dripped onto the substrate particles having the first conductive portions to carry out electroless tin plating, and then reduced with a reducing solution. After that, the particles are taken out by filtering, washed with water, and dried to form the first conductive portion (nickel-boron layer, thickness 0.2 μm) and the second conductive portion (tin layer, thickness 0.25 μm). A conductive particle body having

(2) Preparation of conductive particles (Preparation of particle bodies (resin particles) in flux-containing particles)
After adding the following composition to a 2000 mL separable flask equipped with a 4-neck separable cover, a stirring blade, a three-way cock, a cooling tube and a temperature probe, distilled water is added so that the solid content becomes 10% by weight. Then, the mixture was stirred at 120 rpm and polymerized at 50° C. for 5 hours under a nitrogen atmosphere. The above composition contains 1080 mmol of methyl methacrylate, 10 mmol of ethylene glycol dimethacrylate, 0.5 mmol of 4-(methacryloyloxy)phenyldimethylsulfonium methylsulfate, and 2,2′-azobis{2-[N-(2-carboxy ethyl)amidino]propane}0.5 mmol. After completion of the reaction, the reaction mixture was lyophilized to obtain resin particles (particle size: 360 nm) having sulfone groups derived from 4-(methacryloyloxy)phenyldimethylsulfonium methylsulfate on their surfaces.

(Preparation of Conductive Particles Equipped with Flux-Containing Particles and Flux Film)
The obtained resin particles were dispersed in distilled water under ultrasonic irradiation to obtain a 10% by weight aqueous dispersion (B) of resin particles. After dispersing 10 g of the conductive particle main body obtained in (1) in 500 mL of distilled water, 1 g of dispersion liquid (B) was added and stirred at room temperature for 8 hours. After filtration through a 3 μm mesh filter, the particles were washed with methanol and dried to obtain conductive particles with particle bodies (resin particles). The obtained conductive particles with particle bodies were dispersed in 200 mL of ethanol to obtain a dispersion (C). Thereafter, the dispersion liquid (C) was mixed with 300 mL of ethanol in which 0.5 g of a rosin-based flux was dissolved, and the mixture was stirred for 10 minutes by ultrasonic dispersion at a temperature of 50°C. After filtration through a 3 μm mesh filter, the particles were dried to obtain conductive particles having flux-containing particles and a flux film.

(3) Preparation of conductive material (anisotropic conductive paste) 7 parts by weight of the obtained conductive particles, 25 parts by weight of bisphenol A type phenoxy resin, 4 parts by weight of fluorene type epoxy resin, and 30 parts by weight of phenol novolak type epoxy resin. A conductive material (anisotropic conductive paste) was obtained by blending parts by weight and SI-60L (manufactured by Sanshin Chemical Industry Co., Ltd.), followed by defoaming and stirring for 3 minutes.

(4) Fabrication of Connection Structure A flexible printed circuit board was prepared on which an Au electrode pattern (first electrode, electrode: Ni/Au thin film on Cu) with L/S of 200 μm/200 μm was formed on the upper surface. In addition, a printed circuit board having an Au electrode pattern (second electrode, electrode: Ni/Au thin film on Cu) with L/S of 200 μm/200 μm formed on the lower surface was prepared.

The obtained anisotropic conductive paste was applied onto the printed circuit board so as to have a thickness of 30 μm to form an anisotropic conductive paste layer. Next, the flexible printed circuit board was laminated on the anisotropic conductive paste layer so that the electrodes faced each other. After that, while adjusting the temperature of the head so that the temperature of the anisotropic conductive paste layer becomes 100° C., a pressure heating head is placed on the upper surface of the semiconductor chip, and a pressure of 60 MPa is applied to the anisotropic conductive paste layer. It was cured at 100° C. to obtain a connected structure.

(Example 2)
When producing the particle bodies of the flux-containing particles, the amount of methyl methacrylate in the composition was changed from 1080 mmol to 180 mmol, and 900 mmol of glycidyl methacrylate was added to the composition. Conductive particles, a conductive material and a connection structure were obtained in the same manner as in Example 1 except for the above changes.

(Example 3)
During the preparation of the particle body in the flux-containing particles, 840 mmol of polystyrene and 240 mmol of lauryl methacrylate were added to the composition instead of 1080 mmol of methyl methacrylate. Conductive particles, a conductive material and a connection structure were obtained in the same manner as in Example 1 except for the above changes.

(Example 4)
When producing the particle bodies of the flux-containing particles, the blending amount of methyl methacrylate in the composition was changed from 1080 mmol to 540 mmol, and 540 mmol of glycidyl methacrylate was added to the composition. Conductive particles, a conductive material and a connection structure were obtained in the same manner as in Example 1 except for the above changes.

(Example 5)
Conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that the flux in the flux-containing particles and flux film was changed to benzylamine adipate.

(Example 6)
When forming the first conductive portion, instead of the nickel plating solution, a mixed solution of 200 g/L of copper sulfate, 150 g/L of ethylenediaminetetraacetic acid, 100 g/L of sodium gluconate, and 50 g/L of formaldehyde was used. A copper plating solution adjusted to pH 10.5 with ammonia was prepared. While the suspension (A) was stirred at 65° C., 250 ml of the copper plating solution was dropped into the suspension (A) at 10 ml/min to perform electroless copper plating. After that, the particles are taken out by filtration, washed with water, dried, and the first conductive portion is formed on the surface of the substrate particles. (copper layer, thickness 0.2 μm) was formed. A conductive particle, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that the first conductive portion was a copper layer.

(Example 7)
Example 1 except that no core substance was used and no projections were formed in the preparation of the conductive particle body, and only a tin layer (0.3 μm) was formed in the formation of the conductive portion. Conductive particles, a conductive material and a connection structure were obtained in the same manner.

(Example 8)
A conductive particle, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that only a nickel layer (0.3 μm) was formed as the conductive portion in the preparation of the conductive particle body.

(Example 9)
The substrate particles having the first conductive portion (nickel-boron layer) obtained in Example 1 were added to 100 parts by weight of distilled water and dispersed to obtain a suspension. After that, a reducing gold plating solution containing 0.03 mol/L of gold cyanide and 0.1 mol/L of hydroquinone as a reducing agent was prepared instead of the tin plating solution when forming the second conductive portion. While stirring the resulting suspension at 70° C., the reduction gold plating solution was gradually dropped into the suspension to perform reduction gold plating. After that, by filtering the suspension, the particles are taken out, washed with water, and dried to form the first conductive portion (nickel-boron layer, thickness 0.2 μm) and the second conductive portion (gold layer, thickness 0.2 μm). .25 μm) was obtained. A conductive particle, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particle body was used.

(Comparative example 1)
Conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that the flux-containing particles were not arranged on the surface of the conductive particle body.

(Comparative example 2)
Conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 8, except that the flux-containing particles were not placed on the surface of the conductive particle body.

(Comparative Example 3)
Conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 9, except that the flux-containing particles were not placed on the surface of the conductive particle body.

(Comparative Example 4)
Conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that no flux film was placed on the surface of the conductive particle body.

(evaluation)
(1) Particle diameters of base particles, flux-containing particles, and conductive particles, thickness of conductive portion and flux film The thickness of the conductive portion and the flux film were measured by the method described above. Each particle size was calculated by averaging 20 measurement results.

Also, the ratio of the particle size of the conductive particles to the particle size of the flux-containing particles (particle size of the conductive particles/particle size of the flux-containing particles) was calculated.

(2) Presence or absence of rupture point in compression-displacement curve Using a microcompression tester ("ENT-NEXUS" manufactured by Elionix), a cylinder (diameter 50 μm, made of diamond) was applied at a smooth indenter end face at 25 ° C., maximum test load. The flux-containing particles were compressed under the condition of loading 3.3 mN for 10 seconds. The load value (N) and compression displacement (mm) at this time were measured, a compression-displacement curve was prepared, and the presence or absence of breaking points was confirmed.

(3) Remaining Percentage of Flux-Containing Particles The residual percentage (%) of flux-containing particles of the obtained conductive particles was measured by the method described above.

(4) Removability of Oxide Film With respect to the obtained conductive material, conductive particles were dispersed on a Cu plate with a 1% by weight sulfuric acid aqueous solution. After that, it was heated on a hot plate at 250° C. for 1 minute, and after the heating, it was sufficiently cooled to remove the particles. The removability of the oxide film was judged according to the following criteria (color of Cu plate).

[Criteria for removability of oxide film]
○○○: The Cu plate is orange ○○: The Cu plate is reddish orange ○: The Cu plate is purple ×: The Cu plate is silver and green

(5) Continuity reliability (between upper and lower electrodes)
The connection resistance between the upper and lower electrodes of the obtained 20 connection structures was measured by the 4-probe method. From the relationship of voltage=current×resistance, the connection resistance can be obtained by measuring the voltage when a constant current flows. Conductivity reliability was determined according to the following criteria.

[Continuity Reliability Judgment Criteria]
○○○: Connection resistance is 0.32 Ω or less ○○: Connection resistance is over 0.32 Ω and 0.35 Ω or less ○: Connection resistance is over 0.35 Ω and 0.41 Ω or less ×: Connection resistance is 0 over .41Ω

The results are shown in Tables 1 to 3 below.

1, 1A, 1B, 1C... Conductive particles 11, 11A, 11B, 11C... Conductive particle body 11Ca... Protrusions 12, 12A, 12B, 12C... Flux-containing particles 13, 13A, 13B, 13C... Flux films 21, 21A , 21B, 21C... Base material particles 22, 22A, 22B, 22C... Conductive part 22BA... First conductive part 22BB... Second conductive part 23C... Core substance 81... Connection structure 82... First connection target member 82a ... 1st electrode 83 ... 2nd connection object member 83a ... 2nd electrode 84 ... connection part

Claims

A conductive particle body, a plurality of flux-containing particles, and a flux film,
The conductive particle body comprises a base particle and a conductive portion arranged outside the base particle,
The flux-containing particles are arranged outside the conductive particle body,
Conductive particles, wherein the flux film is disposed outside the conductive particle body.
the flux-containing particles comprise a particle body and a flux,
2. The conductive particles according to claim 1, wherein the particle bodies are resin particles.
the material of the resin particles contains a polymerizable monomer,
3. The conductive particles according to claim 2, wherein the homopolymer of the polymerizable monomer has a glass transition temperature of 80[deg.] C. or higher.
4. The flux-containing particles according to any one of claims 1 to 3, wherein the flux-containing particles do not have a breaking point in a compression-displacement curve when a maximum test load of 3.3 mN is applied to the flux-containing particles for 10 seconds. conductive particles.
The conductive particles according to any one of claims 1 to 4, wherein the conductive portion contains tin.
The conductive particles according to any one of claims 1 to 5, wherein the ratio of the particle size of the conductive particles to the particle size of the flux-containing particles is 3 or more and 500 or less.
The conductive particles according to any one of claims 1 to 6, wherein the conductive particles have a particle diameter of 1 µm or more and 50 µm or less.
When a conductive particle-containing liquid obtained by adding 3 parts by weight of the conductive particles to 100 parts by weight of ethanol is subjected to ultrasonic treatment for 5 minutes at 20° C. and 40 kHz, the number of flux-containing particles obtained by the following formula (1) is The conductive particles according to any one of claims 1 to 7, which have a residual rate of 99% or less.
Remaining rate of flux-containing particles (%)=(coverage ratio of flux-containing particles after ultrasonic treatment/coverage ratio of flux-containing particles before ultrasonic treatment)×100 Equation (1)
A conductive material comprising the conductive particles according to any one of claims 1 to 8 and a binder resin.
a first connection target member having a first electrode on its surface;
a second connection target member having a second electrode on its surface;
comprising the first connection target member and a connection portion connecting the second connection target member,
The material of the connection portion contains the conductive particles according to any one of claims 1 to 8,
A connection structure in which the first electrode and the second electrode are electrically connected by the conductive particle body.