JP2015118933A - Conductive particle, conductive material and connection structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive particle capable of making initial connection resistance low when a connection structure is obtained by electrically connecting electrodes by the conductive particle, and capable of maintaining connection resistance low even when the connection structure is exposed in a presence of acid.SOLUTION: The conductive particle 1 has a substrate particle 11, a first conductive layer 12 arranged on a surface of the substrate particle 11 and formed from silver or copper and a second conducive layer 13 arranged on an outside surface of the first conductive layer 12 and formed from nickel, the second conductive layer 13 contains nickel, boron, tungsten or molybdenum.

Description

  The present invention relates to conductive particles having substrate particles and a conductive layer disposed on the surface of the substrate particles. The present invention also relates to a conductive material and a connection structure using the conductive particles.

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

  In order to obtain various connection structures, the anisotropic conductive material is, for example, a connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)) or a connection between a semiconductor chip and a flexible printed circuit board (COF ( Chip on Film)), connection between a semiconductor chip and a glass substrate (COG (Chip on Glass)), connection between a flexible printed circuit board and a glass epoxy substrate (FOB (Film on Board)), and the like.

  As an example of the conductive particles used for the anisotropic conductive material, the following Patent Document 1 includes a conductive layer formed of copper, a copper alloy, silver or a silver alloy, and the conductive layer formed on the conductive layer. And a conductive particle having a surface layer formed of nickel or a nickel alloy. In the example of Patent Document 1, resin particles, a conductive layer covering the surface of the resin particles and formed of copper, and formed on the conductive layer and formed of nickel. In other words, conductive particles are described in which the surface layer formed of nickel has protrusions on the outer surface.

JP 2013-206823 A

  When the connection structure is obtained by connecting the electrodes using conventional conductive particles as described in Patent Document 1, when the connection structure is exposed in the presence of an acid, the connection between the electrodes Connection resistance may increase.

  Further, when the surface layer of the conductive particles is nickel, an oxide film is easily formed on the surface layer. Furthermore, an oxide film may be formed on the surface of the electrode. In the conventional conductive particles as described in Patent Document 1, if an oxide film is formed on the surface layer or an oxide film is formed on the surface of the electrode, the oxide film sufficiently protrudes when the electrodes are connected. The initial connection resistance may be increased without being broken.

  The object of the present invention is to reduce the initial connection resistance when electrically connecting the electrodes with conductive particles to obtain a connection structure, and to expose the connection structure in the presence of an acid. Even if it is made, it is providing the electroconductive particle which can maintain a connection resistance low.

  Moreover, this invention provides the electrically-conductive material and connection structure using the said electroconductive particle.

  According to a wide aspect of the present invention, a base particle, a first conductive layer disposed on the surface of the base particle and formed of silver or copper, and outside the first conductive layer There is provided a conductive particle comprising a second conductive layer disposed on the surface and formed of nickel, wherein the second conductive layer includes nickel, boron, and tangsten or molybdenum.

  On the specific situation with the electroconductive particle which concerns on this invention, content of nickel in a said 2nd conductive layer is 50 to 99 weight%.

  On the specific situation with the electroconductive particle which concerns on this invention, content of tungsten or molybdenum in a said 2nd conductive layer is 0.1 to 5.0 weight%.

  On the specific situation with the electroconductive particle which concerns on this invention, content of the boron in a said 2nd conductive layer is 0.1 to 5.0 weight%.

  In a specific aspect of the conductive particle according to the present invention, the second conductive layer has a plurality of protrusions on the outer surface.

  On the specific situation with the electroconductive particle which concerns on this invention, the thickness of a said 2nd conductive layer is 0.1 times or more and 10 times or less of the thickness of a said 1st conductive layer.

  On the specific situation with the electroconductive particle which concerns on this invention, a said 1st conductive layer is a copper layer formed with copper.

  On the specific situation with the electroconductive particle which concerns on this invention, the said base material particle is a resin particle or an organic inorganic hybrid particle.

  On the specific situation with the electroconductive particle which concerns on this invention, the said base material particle is the said organic-inorganic hybrid particle.

  On the specific situation with the electroconductive particle which concerns on this invention, the outer surface of the said 2nd conductive layer is rust-proofed.

  On the specific situation with the electroconductive particle which concerns on this invention, the said electroconductive particle is further equipped with the insulating substance arrange | positioned on the outer surface of the said 2nd electroconductive layer.

  According to a wide aspect of the present invention, there is provided a conductive material including the above-described conductive particles and a binder resin.

  According to a wide aspect of the present invention, a first connection target member having a first electrode on the surface, a second connection target member having a second electrode on the surface, the first connection target member, and the A connection portion connecting the second connection target member, and the connection portion is formed of the above-described conductive particles or formed of a conductive material including the conductive particles and a binder resin. There is provided a connection structure in which the first electrode and the second electrode are electrically connected by the conductive particles.

  The conductive particles according to the present invention include base particles, a first conductive layer that is disposed on the surface of the base particles and is formed of silver or copper, and the outside of the first conductive layer. Since the second conductive layer is disposed on the surface and formed of nickel, boron, and tangsugten or molybdenum, the electrodes are electrically connected to each other by the conductive particles according to the present invention. When the body is obtained, the initial connection resistance can be lowered, and even if the connection structure is exposed to the presence of an acid, the connection resistance can be kept low.

FIG. 1 is a cross-sectional view showing conductive particles according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing conductive particles according to the second embodiment of the present invention. FIG. 3 is a cross-sectional view showing conductive particles according to the third embodiment of the present invention. FIG. 4 is a cross-sectional view showing conductive particles according to the fourth embodiment of the present invention. FIG. 5 is a sectional view showing conductive particles according to the fifth embodiment of the present invention. FIG. 6 is a cross-sectional view schematically showing a connection structure using conductive particles according to the first embodiment of the present invention.

  Details of the present invention will be described below.

(Conductive particles)
The conductive particles according to the present invention include base particles, a first conductive layer disposed on the surface of the base particles and formed of silver or copper, and outside the first conductive layer. And a second conductive layer disposed on the surface and formed of nickel. In the conductive particles according to the present invention, the second conductive layer contains nickel, boron, and tangstenene or molybdenum. The first conductive layer is a silver layer formed of silver or a copper layer formed of copper. The second conductive layer is a nickel layer formed of nickel (also referred to as a nickel layer when boron and tungsten or molybdenum are included), specifically a nickel-boron-tungsten / molybdenum layer.

  By adopting the above-described configuration in the conductive particles according to the present invention, when a connection structure is obtained by electrically connecting the electrodes using the conductive particles according to the present invention, the initial connection resistance is lowered. be able to. Furthermore, even if the obtained connection structure is exposed to the presence of an acid, the connection resistance can be kept low. In particular, when the conductive particles are used for electrical connection between the electrodes, the conductive particles are generally compressed. When the conductive particles are compressed, the second conductive layer may be cracked. Even if a crack occurs in the second conductive layer, the corrosion in the second conductive layer is suppressed, so that the connection resistance can be effectively kept low.

  Further, when the surface layer of the conductive particles is a nickel layer, an oxide film is easily formed on the nickel layer. An oxide film may also be formed on the surface of the electrode. In the present invention, since the nickel layer contains nickel, boron, and tungsten or molybdenum, the nickel layer is hard. For this reason, since the said oxide film can be penetrated favorably at the time of the connection between electrodes, an initial connection resistance can be made low.

  Moreover, in the electroconductive particle which concerns on this invention, the silver layer or the copper layer is arrange | positioned inside the said nickel layer, and this silver layer and a copper layer are comparatively soft. In the conductive particles in which the nickel layer is disposed on the outer surface of the silver layer or the copper layer, there is a problem that it is generally difficult for the protrusions to sufficiently penetrate the oxide film. On the other hand, by forming a nickel layer formed of nickel, boron and tangsugten or molybdenum, even if a silver layer or a copper layer is disposed inside the nickel layer, an oxide film is formed at the time of connection between the electrodes. Can be sufficiently penetrated, and the initial connection resistance can be effectively reduced. When the nickel layer is formed on the outer surface of the silver layer or the copper layer, the nickel layer containing boron and tungsten or molybdenum plays a major role in obtaining the effects of the present invention. In addition, when the conductive layer inside the nickel layer is a silver layer or a copper layer, the effect of reducing the connection resistance is greater than when the conductive layer inside the nickel layer is a conductive layer other than the silver layer or the copper layer. It gets quite big.

  Also, the copper layer is relatively harder than the silver layer. For this reason, when the copper layer is present inside the nickel layer, the protrusion penetrates the oxide film more effectively and the initial connection resistance is further reduced.

  In the conductive particles according to the present invention, when resin particles or organic-inorganic hybrid particles are arranged inside the first conductive layer, the resin particles and organic-inorganic hybrid particles are relatively soft. In the conductive particles in which the base particles are resin particles or organic / inorganic hybrid particles, there is a problem that it is generally difficult for the protrusions to sufficiently penetrate the oxide film. In contrast, by forming a nickel layer formed of nickel, boron, and tungsten or molybdenum, even if the base particles are resin particles or organic-inorganic hybrid particles, an oxide film is formed at the time of connection between the electrodes. It is possible to sufficiently penetrate, and the initial connection resistance can be effectively reduced. When the substrate particles are resin particles or organic / inorganic hybrid particles, the nickel layer containing nickel, boron, tungsten, or molybdenum plays a major role in obtaining the effects of the present invention. In addition, when the substrate particles are resin particles or organic-inorganic hybrid particles, the effect of reducing the connection resistance is considerably greater than when the substrate particles are not resin particles and organic-inorganic hybrid particles.

  From the viewpoint of further reducing the initial connection resistance by allowing the oxide film to penetrate through the protrusion, in the conductive particle according to the present invention, the second conductive layer may have a plurality of protrusions on the outer surface. preferable. From the viewpoint of further reducing the initial connection resistance by penetrating the oxide film by the protrusion, in the conductive particles according to the present invention, the average height of the protrusion is the protrusion of the second conductive layer. It is preferable that the thickness is larger than the thickness of the portion where no is present.

  The average height B of the protrusions is preferably larger than the thickness A of the portion of the second conductive layer where the protrusions are not present. However, the average height B of the protrusions may be equal to or less than the thickness A of the portion of the second conductive layer where the protrusions are not present. The average height B of the protrusions is an average of the heights of a plurality of protrusions per one conductive particle. The thickness A of the portion without the protrusion of the second conductive layer is an average of the thickness of the portion without the protrusion of the second conductive layer per one conductive particle.

  From the viewpoint of further reducing the initial connection resistance and further suppressing the increase in connection resistance in the presence of an acid, the average height B of the protrusion is the portion of the second conductive layer where the protrusion is not present. The thickness A is more preferably 1.1 times or more, and even more preferably 2.2 times or more. From the viewpoint of suppressing excessive bending of the protrusions, further reducing variation in connection resistance, and further improving connection reliability, the average height B of the protrusions does not include the protrusions of the second conductive layer. It is preferably 6 times or less of the thickness A of the part, more preferably 3 times or less.

  The height of the projection is a virtual line of the conductive portion (dashed line shown in FIG. 1) on the assumption that there is no projection on the line (dashed line L1 shown in FIG. 1) connecting the center of the conductive particles and the tip of the projection. L2) Indicates the distance from the top (on the outer surface of the spherical conductive particles assuming no projection) to the tip of the projection. That is, in FIG. 1, the distance from the intersection of the broken line L1 and the broken line L2 to the tip of the protrusion is shown.

  From the viewpoint of further reducing the initial connection resistance and further suppressing the increase in connection resistance in the presence of an acid, the thickness of the second conductive layer is 0.1% of the thickness of the first conductive layer. It is preferably at least twice, more preferably at least 0.5 times, more preferably at most 15 times, and even more preferably at most 10 times.

  The thickness of the first conductive layer is an average thickness of the entire first conductive layer per one conductive particle. The thickness of the second conductive layer is an average thickness of the entire second conductive layer per one conductive particle.

  Hereinafter, the present invention will be clarified by describing specific embodiments and examples of the present invention with reference to the drawings.

  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 base particle 11, a first conductive layer 12, a second conductive layer 13, a plurality of core substances 14, and a plurality of insulating substances 15. The first conductive layer 12 is made of silver or copper. The second conductive layer 13 is made of nickel and contains nickel, boron, tungsten, or molybdenum. In the conductive particles 1, a multi-layered conductive layer is formed. The base particle 11 is, for example, a resin particle.

  The first conductive layer 12 is disposed on the surface of the base particle 11. The first conductive layer 12 is in contact with the base particle 11. The first conductive layer 12 is disposed between the base particle 11 and the second conductive layer 13. The second conductive layer 13 is disposed on the outer surface of the first conductive layer 12. The second conductive layer 13 is in contact with the first conductive layer 12. The conductive particle 1 is a coated particle in which the surface of the base particle 11 is covered with the first conductive layer 12 and the second conductive layer 13.

  The conductive particle 1 has a plurality of protrusions 1a on a conductive surface. The first conductive layer 12 and the second conductive layer 13 have a plurality of protrusions 12a and 13a on the outer surface. A plurality of core substances 14 are arranged on the surface of the base particle 11. The plurality of core materials 14 are embedded in the first conductive layer 12 and the second conductive layer 13. The core substance 14 is disposed inside the protrusions 1a, 12a, and 13a. The first conductive layer 12 and the second conductive layer 13 cover a plurality of core substances 14. The outer surfaces of the first conductive layer 12 and the second conductive layer 13 are raised by the plurality of core materials 14 to form protrusions 1a, 12a, and 13a. Thus, the electroconductive particle which concerns on this invention has a processus | protrusion on the electroconductive surface. The conductive particles according to the present invention have protrusions on the outer surface of the second conductive layer. The core material is preferably disposed inside or inside the second conductive layer. The core material may be disposed inside or inside the first conductive layer. Note that when the core substance is disposed inside or inside the first conductive layer, the core substance is disposed inside the second conductive layer.

  The electroconductive particle 1 has the insulating substance 15 arrange | positioned on the electroconductive surface. The conductive particles 1 have an insulating material 15 disposed on the outer surface of the second conductive layer 13. At least a part of the outer surface of the second conductive layer 13 is covered with an insulating material 15. The insulating substance 15 is made of an insulating material and is an insulating particle. Thus, it is preferable that the electroconductive particle which concerns on this invention has the insulating substance arrange | positioned on the outer surface of a 2nd conductive layer.

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

  A conductive particle 1 </ b> A shown in FIG. 2 includes substrate particles 11, a first conductive layer 12 </ b> A, a second conductive layer 13, and a plurality of insulating substances 15. The first conductive layer 12A is made of silver or copper.

  The conductive particles 1A do not have a core substance. The first conductive layer 12A has a first portion and a second portion that is thicker than the first portion. Accordingly, the first conductive layer 12A has a protrusion 12Aa on the outer surface. A portion excluding the plurality of protrusions 1Aa and 12Aa is the first portion of the first conductive layer 12A. The plurality of protrusions 1 </ b> Aa and 12 </ b> Aa are the second portions where the thickness of the first conductive layer 12 is thick.

  Like the conductive particles 1A, the conductive particles according to the present invention do not necessarily use a core substance in order to form a plurality of protrusions on the outer surface of the second conductive layer.

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

  A conductive particle 1 </ b> B shown in FIG. 3 includes base material particles 11, a first conductive layer 12 </ b> B, a second conductive layer 13 </ b> B, and a plurality of core substances 14. The first conductive layer 12B is made of silver or copper. The second conductive layer 13B is made of nickel and contains nickel, boron, tungsten, or molybdenum.

  The conductive particles 1B have a plurality of protrusions 1Ba on the conductive surface. The first conductive layer 12B has no protrusion on the outer surface. The outer shape of the first conductive layer 12B is spherical. The second conductive layer 13B has a plurality of protrusions 13Ba on the outer surface. A plurality of core materials 14 are disposed on the outer surface of the first conductive layer 12B. The plurality of core materials 14 are embedded in the second conductive layer 13B. The core substance 14 is disposed inside the protrusions 1Ba and 13Ba. The second conductive layer 13 </ b> B covers a plurality of core materials 14. The outer surface of the second conductive layer 13B is raised by the plurality of core materials 14, and the protrusions 1Ba and 13Ba are formed.

  Like the electroconductive particle 1B, the electroconductive particle which concerns on this invention does not need to have a processus | protrusion on the outer surface of a 1st electroconductive layer.

  The conductive particles 1B do not have an insulating material on the outer surface of the second conductive layer 13B. The conductive particles according to the present invention do not necessarily have an insulating material disposed on the outer surface of the second conductive layer.

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

  A conductive particle 1 </ b> C illustrated in FIG. 4 includes base material particles 21, a first conductive layer 12, a second conductive layer 13, a plurality of core materials 14, and a plurality of insulating materials 15. The conductive particles 1C have a plurality of protrusions 1Ca on the conductive surface.

  In the conductive particles 1 shown in FIG. 1, the base particles 11 are used, whereas in the conductive particles 1C shown in FIG. 4, the base particles 21 are used. The base particle 21 has a core 21X and a shell 21Y disposed on the surface of the core 21X. The base particle 21 is a core-shell particle. The base particle 21 is, for example, an organic / inorganic hybrid particle.

  Thus, in the electroconductive particle which concerns on this invention, a base material particle can be changed suitably.

  FIG. 5 is a sectional view showing conductive particles according to the fifth embodiment of the present invention.

  A conductive particle 1 </ b> D illustrated in FIG. 5 includes a base particle 11, a first conductive layer 12 </ b> D, a second conductive layer 13 </ b> D, and a plurality of insulating substances 15. The first conductive layer 12D is made of silver or copper. The second conductive layer 13D is made of nickel and contains nickel, boron, tungsten, or molybdenum.

  The conductive particles 1D have an insulating material 15 disposed on a conductive surface. The conductive particles 1D have an insulating material 15 disposed on the outer surface of the second conductive layer 13D.

  The conductive particles 1D have no core material. The conductive particles 1D are spherical. The conductive particles 1D do not have protrusions on the outer surface. The outer shape of the first conductive layer 12D and the second conductive layer 13D is spherical. The first conductive layer 12D and the second conductive layer 13D have no protrusion on the outer surface.

  Like the conductive particles 1D, the conductive particles according to the present invention do not necessarily have to have protrusions. The conductive particles according to the present invention may be spherical.

  Hereinafter, other details of the conductive particles will be described.

[Base material particles]
Examples of the substrate particles include resin particles, inorganic particles excluding metal particles, organic-inorganic hybrid particles, and metal particles. The base particle may have a core and a shell disposed on the surface of the core, or may be a core-shell particle. The substrate particles are preferably substrate particles excluding metal particles, and more preferably resin particles, inorganic particles excluding metal particles, or organic-inorganic hybrid particles.

  The substrate particles are more preferably resin particles or organic-inorganic hybrid particles, and may be resin particles or organic-inorganic hybrid particles. By using these preferable base particles, conductive particles more suitable for electrical connection between the electrodes can be obtained.

  When connecting between electrodes using the said electroconductive particle, after arrange | positioning the said electroconductive particle between electrodes, the said electroconductive particle is compressed by crimping | bonding. When the substrate particles are resin particles or organic-inorganic hybrid particles, the conductive particles are easily deformed during the pressure bonding, and the contact area between the conductive particles and the electrode is increased. For this reason, the connection resistance between electrodes becomes still lower.

  Various organic materials are suitably used as the resin for forming the resin particles. Examples of the resin for forming 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; Alkylene terephthalate, polycarbonate, polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polysulfone, polyphenylene Oxide, polyacetal, polyimide, polyamideimide, polyether ether Tons, polyethersulfone, and polymers such as obtained by a variety of polymerizable monomer having an ethylenically unsaturated group is polymerized with one or more thereof. Resin for forming the resin particles can be designed and synthesized, and the hardness of the base particles can be easily controlled within a suitable range, which is suitable for conductive materials and having physical properties at the time of compression. Is preferably a polymer obtained by polymerizing one or more polymerizable monomers having a plurality of ethylenically unsaturated groups.

  When the resin particles are obtained by polymerizing a monomer having an ethylenically unsaturated group, the monomer having an ethylenically unsaturated group includes a non-crosslinkable monomer and a crosslinkable monomer. And so on.

  Examples of the non-crosslinkable monomer include styrene monomers such as styrene and α-methylstyrene; carboxyl group-containing monomers such as (meth) acrylic acid, maleic acid, and maleic anhydride; (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) acrylates such as meth) acrylate and isobornyl (meth) acrylate; oxygen such as 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate and glycidyl (meth) acrylate (Meth) acrylates; nitrile-containing monomers such as (meth) acrylonitrile; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether; vinyl acids such as vinyl acetate, vinyl butyrate, vinyl laurate, vinyl stearate Esters; Unsaturated hydrocarbons such as ethylene, propylene, isoprene and butadiene; Halogen-containing monomers such as trifluoromethyl (meth) acrylate, pentafluoroethyl (meth) acrylate, vinyl chloride, vinyl fluoride and chlorostyrene Is mentioned.

  Examples of the crosslinkable monomer include tetramethylolmethane tetra (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and dipenta Erythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri (meth) acrylate, glycerol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) Polyfunctional (meth) acrylates such as acrylate, (poly) tetramethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate; triallyl (iso) cyanure Silane-containing monomers such as triallyl trimellitate, divinylbenzene, diallyl phthalate, diallylacrylamide, diallyl ether, γ- (meth) acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, vinyltrimethoxysilane It is done.

  The resin particles can be obtained by polymerizing the polymerizable monomer having an 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 non-crosslinked seed particles.

  In the case where the substrate particles are inorganic particles or organic-inorganic hybrid particles excluding metal particles, examples of the inorganic material for forming the substrate particles include silica, alumina, barium titanate, zirconia, and carbon black. . The inorganic substance is preferably not a metal. The particles formed by the silica are not particularly limited. For example, after forming a crosslinked polymer particle by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups, firing may be performed as necessary. The particle | grains obtained by performing are mentioned. Examples of the organic / inorganic hybrid particles include organic / inorganic hybrid particles formed of 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. The core is preferably an organic core. The shell is preferably an inorganic shell. From the viewpoint of effectively reducing the connection resistance between the electrodes, the base material 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 forming the organic core include the resin for forming the resin particles described above.

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

  The particle size of the core is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 500 μm or less, more preferably 100 μm or less, still more preferably 50 μm or less, particularly preferably 20 μm or less, and most preferably 10 μm or less. . When the particle size of the core is not less than the above lower limit and not more than the above upper limit, more suitable conductive particles can be obtained by electrical connection between the electrodes, and the base particles can be suitably used for the use of conductive particles. Become. For example, when the core particle size is not less than the lower limit and not more than the upper limit, when the electrodes are connected using the conductive particles, the contact area between the conductive particles and the electrodes is sufficiently large, and Aggregated conductive particles are hardly formed when the conductive layer is formed. Further, the distance between the electrodes connected via the conductive particles does not become too large, and the conductive layer is difficult to peel from the surface of the base material particles.

  The particle diameter of the core means a diameter when the core is a perfect sphere, and means a maximum diameter when the core is a shape other than a true sphere. Moreover, the particle size of a core means the average particle size which measured the core with the arbitrary particle size measuring apparatus. For example, a particle size distribution measuring machine using principles such as laser light scattering, electrical resistance value change, and image analysis after imaging can be used.

  The thickness of the shell is preferably 100 nm or more, more preferably 200 nm or more, preferably 5 μm or less, more preferably 3 μm or less. When the thickness of the shell is not less than the above lower limit and not more than the above upper limit, conductive particles more suitable for electrical connection between the electrodes can be obtained, and the base particles can be suitably used for the use of conductive particles. . The thickness of the shell is an average thickness per base particle. The thickness of the shell can be controlled by controlling the sol-gel method.

  When the substrate particles are metal particles, examples of the metal for forming the metal particles include silver, copper, nickel, silicon, gold, and titanium. However, the substrate particles are preferably not metal particles.

  The particle diameter of the substrate particles is particularly preferably 0.1 μm or more and 5 μm or less. When the particle diameter of the substrate particles is in the range of 0.1 to 5 μm, even when the distance between the electrodes is small and the thickness of the conductive layer is increased, small conductive particles can be obtained. From the viewpoint of obtaining even smaller conductive particles even when the distance between the electrodes is further reduced or the conductive layer is thickened, the particle diameter of the base particles is preferably 0.5 μm or more. More preferably, it is 2 μm or more, preferably 3 μm or less.

  The particle diameter of the base particle indicates a diameter when the base particle is a true sphere, and indicates a maximum diameter when the base particle is not a true sphere.

The compression modulus (10% K value) when the above base particle is compressed by 10% is preferably 2500 mN / mm ² or more, more preferably 5000 mN / mm ² or more, preferably 10000 mN / mm ² or less, more preferably 7000 mN. / Mm ² or less. When the 10% K value is not less than the above lower limit and not more than the above upper limit, the connection resistance between the electrodes is further reduced.

  The compression elastic modulus (10% K value) of the substrate particles can be measured as follows.

  Using a micro-compression tester, the substrate particles are compressed under the conditions of a smooth indenter end face of a cylinder (diameter 100 μm, made of diamond) at 25 ° C., a compression rate of 0.3 mN / sec, and a maximum test load of 20 mN. The load value (N) and compression displacement (mm) at this time are measured. From the measured value obtained, the compression elastic modulus can be obtained by the following formula. As the micro compression tester, for example, “Fischer Scope H-100” manufactured by Fischer is used.

10% K value (N / mm ² ) = (3/2 ^1/2 ) · F · S ⁻³ / ² · R ^−1/2
F: Load value (N) when the base material particle is 10% compressively deformed
S: Compression displacement (mm) when the substrate particles are 10% compressively deformed
R: radius of base particle (mm)

  The compression elastic modulus represents the hardness of the base particle universally and quantitatively. By using the compression elastic modulus, the hardness of the base particle can be expressed quantitatively and uniquely.

[Conductive layer]
The first conductive layer is made of silver or copper. The first conductive layer includes not only the case where only silver or copper is used as the metal, but also the case where silver and other metals are used, and the case where copper and other metals are used. The first conductive layer may be a silver alloy layer or a copper alloy layer.

  The first conductive layer may be a silver layer formed of silver or a copper layer formed of copper. Since the effect of the present invention can be obtained more effectively, the first conductive layer is preferably a copper layer formed of copper.

  Examples of the metal other than silver in the silver layer and the metal other than copper in the copper layer include, for example, gold, silver, copper, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, nickel, palladium, chromium, Examples thereof include titanium, antimony, bismuth, thallium, germanium, cadmium, silicon, tungsten, molybdenum, tin-doped indium oxide (ITO), and solder. As for these metals, only 1 type may be used and 2 or more types may be used together.

  The first conductive layer preferably contains silver or copper as a main metal. In 100% by weight of the first conductive layer, the silver or copper content (silver content or copper content) is preferably 50% by weight or more. In 100% by weight of the first conductive layer, the content of silver or copper is preferably 70% by weight or more, more preferably 80% by weight or more, and further preferably 99% by weight or more. When the content of silver or copper is not less than the above lower limit, the electrode and the conductive particles are more appropriately brought into contact with each other, and the connection resistance between the electrodes is further reduced.

  Another conductive layer may be disposed between the first conductive layer and the second conductive layer. The second conductive layer is preferably laminated on the outer surface of the first conductive layer so that the second conductive layer is in contact therewith.

  The second conductive layer is made of nickel. The second conductive layer includes not only the case where nickel is used as the metal but also the case where nickel and another metal are used. The second conductive layer may be a nickel alloy layer.

  As the metal other than nickel, tungsten and molybdenum in the second conductive layer, gold, silver, copper, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, palladium, chromium, titanium, antimony, bismuth, Examples include thallium, germanium, cadmium, silicon, tin-doped indium oxide (ITO), and solder. As for these metals, only 1 type may be used and 2 or more types may be used together.

  The second conductive layer preferably contains nickel as a main metal. In 100% by weight of the second conductive layer, the nickel content is preferably 50% by weight or more. In 100% by weight of the second conductive layer, the nickel content is preferably 75% by weight or more, more preferably 85% by weight or more, still more preferably 95% by weight or more, and preferably 99% by weight or less. When the nickel content is at least the above lower limit, the oxide film on the surface of the electrode is more effectively removed, and the connection resistance between the electrodes is further reduced.

  The second conductive layer contains boron. In 100% by weight of the second conductive layer, the boron content is preferably 0.1% by weight or more, more preferably 1% by weight or more, preferably 10% by weight or less, more preferably 5.0% by weight or less. is there. When the boron content is less than or equal to the lower limit and the upper limit, the resistance of the second conductive layer is further reduced, and the second conductive layer further contributes to the reduction of connection resistance. The second conductive layer may contain phosphorus.

  The second conductive layer contains tungsten or molybdenum. The second conductive layer may contain tungsten or molybdenum. When the second conductive layer contains nickel, boron, tungsten, or molybdenum, the second conductive layer and the protrusion can be further hardened, and the initial connection resistance can be effectively reduced.

  In 100% by weight of the second conductive layer, the content of tungsten or molybdenum (the content of tungsten or the content of molybdenum) is preferably 0.1% by weight or more, more preferably 0.2% by weight or more, preferably It is 5.0 wt% or less, more preferably 2.5 wt% or less. When the content of tungsten or molybdenum is not more than the above lower limit and the above upper limit, the second conductive layer is effectively hardened, and the second conductive layer further contributes to a reduction in connection resistance.

  Another conductive layer may be disposed on the outer surface of the second conductive layer. It is preferable that the second conductive layer is disposed on the outermost surface of the conductive layer in the conductive particles. The conductive surface layer of the conductive particles is preferably the second conductive layer.

  The content of nickel is preferably 40% by weight or more, more preferably 60% by weight in 100% by weight of the entire conductive layer in the conductive particles and 100% by weight of the total of the first conductive layer and the second conductive layer. % Or more, preferably 92% by weight or less, more preferably 80% by weight or less. When the nickel content is not less than the above lower limit, the surface of the conductive particles and the oxide film on the surface of the electrode are more effectively removed, and the connection resistance between the electrodes is further reduced.

  Silver or copper content (silver content or copper content) in 100% by weight of the entire conductive layer in the conductive particles and in 100% by weight of the total of the first conductive layer and the second conductive layer. Is preferably 5% by weight or more, more preferably 10% by weight or more, preferably 60% by weight or less, more preferably 25% by weight or less. When the content of silver or copper is not less than the above lower limit, the electrode and the conductive particles are more appropriately brought into contact with each other, and the connection resistance between the electrodes is further reduced.

  The method for forming the conductive layer is not particularly limited. Examples of the method for forming the conductive layer include a method by electroless plating, a method by electroplating, a method by physical vapor deposition, and a method of coating the surface of particles with metal powder or a paste containing metal powder and a binder. Is mentioned. Especially, since formation of the said conductive layer is simple, the method by electroless plating is preferable. Examples of the method by physical vapor deposition include methods such as vacuum vapor deposition, ion plating, and ion sputtering.

  The thickness of the first conductive layer is preferably 5 nm or more, more preferably 15 nm or more, preferably 100 nm or less, more preferably 40 nm or less. When the thickness of the first conductive layer is not less than the above lower limit and not more than the above upper limit, the electrode and the conductive particles are more appropriately in contact with each other, and the connection resistance between the electrodes is further reduced.

  The thickness of the second conductive layer is preferably 36 nm or more, more preferably 60 nm or more, preferably 295 nm or less, more preferably 130 nm or less. When the thickness of the second conductive layer is not less than the above lower limit and not more than the above upper limit, the oxide film on the surface of the electrode is more effectively removed, and the connection resistance between the electrodes is further reduced.

  The total thickness of the conductive layer and the total thickness of the first conductive layer and the second conductive layer are preferably 5 nm or more, more preferably 10 nm or more, still more preferably 20 nm or more, particularly preferably 41 nm or more, Most preferably, it is 50 nm or more, preferably 1000 nm or less, more preferably 800 nm or less, even more preferably 500 nm or less, still more preferably 400 nm or less, particularly preferably 395 nm or less, and most preferably 300 nm or less. When the total thickness of the conductive layer and the total thickness of the first conductive layer and the second conductive layer are not less than the lower limit, the conductivity of the conductive particles is further improved. When the total thickness of the conductive layer and the total thickness of the first conductive layer and the second conductive layer are not more than the upper limit, the difference in thermal expansion coefficient between the base particles and the conductive layer is reduced. It becomes difficult to peel the conductive layer from the base particles.

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

  The particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 100 μm or less, more preferably 20 μm or less, and even more preferably 5 μm or less. When the particle diameter of the conductive particles is not less than the above lower limit and not more than the above upper limit, the contact area between the conductive particles and the electrodes is sufficiently large when the electrodes are connected using the conductive particles, and the conductive layer When forming the conductive particles, it becomes difficult to form aggregated conductive particles. Further, the distance between the electrodes connected via the conductive particles does not become too large, and the conductive layer is difficult to peel from the surface of the base material particles.

  The particle diameter of the conductive particles indicates the diameter when the conductive particles are true spherical, and indicates the maximum diameter when the conductive particles are not true spherical.

  The conductive particles according to the present invention preferably have a plurality of protrusions on the conductive surface. The second conductive layer preferably has a plurality of protrusions on the outer surface. The first conductive layer preferably has a plurality of protrusions on the outer surface. An oxide film is often formed on the surface of the electrode connected by the conductive particles. By using conductive particles having conductive protrusions, the oxide particles are effectively excluded by the protrusions by arranging the conductive particles between the electrodes and then pressing them. For this reason, an electrode and electroconductive particle can be contacted still more reliably and the connection resistance between electrodes can be made low. Further, when the conductive particles have an insulating material on the surface, or when the conductive particles are dispersed in the resin and used as a conductive material, the conductive particles and the electrodes are insulated by the protrusions of the conductive particles. Substances or resins can be effectively excluded. For this reason, the conduction | electrical_connection reliability between electrodes can be improved.

  Since the effect of the present invention is excellent, the number of protrusions (the number of protrusions) on the outer surface of the second conductive layer per one of the conductive particles is preferably 3 or more, more preferably 5 or more, more preferably 10 or more, more preferably 20 or more. The upper limit of the number of protrusions is not particularly limited. Since the effect of the present invention is excellent, the number of protrusions on the outer surface of the conductive layer per conductive particle is preferably 1000 or less, more preferably 500 or less, and still more preferably 300 or less.

  The average height of the plurality of protrusions in the second conductive layer 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 protrusions is not less than the above lower limit and not more than the above upper limit, the connection resistance between the electrodes is effectively reduced.

[Core material]
Since the core substance is embedded in the conductive layer, it is easy for the conductive layer to have a plurality of protrusions on the outer surface. However, in order to form protrusions on the outer surfaces of the conductive particles and the conductive layer, it is not always necessary to use a core substance, and it is preferable not to use a core substance. The conductive particles preferably do not have a core material for raising the outer surface of the conductive layer. It is preferable that the conductive layer does not contain a core material for raising the outer surface of the conductive layer. When the core material is used, the core material is preferably disposed inside or inside the conductive layer.

  As a method for forming the protrusions, a method of forming a conductive layer by electroless plating after attaching a core substance to the surface of the base particle, and a method of forming a conductive layer by electroless plating on the surface of the base particle And a method of forming a conductive layer by electroless plating, a method of adding a core material during electroless plating, and forming a conductive layer by electroless plating.

  As a method of arranging the core substance, for example, a core substance is added to a dispersion liquid of base particles, and the core substance is accumulated and adhered to the surface of the base particles by, for example, van der Waals force. Examples thereof include a method of adding a core substance to a container containing base particles and the like, and causing the core substance to adhere to the surface of the base particles by a mechanical action such as rotation of the container. Especially, since the quantity of the core substance to adhere is easy to control, the method of accumulating and making a core substance accumulate on the surface of the base material particle etc. in a dispersion liquid is preferable.

  Examples of the material constituting the core material include conductive materials and non-conductive materials. Examples of the conductive material include conductive non-metals such as metals, metal oxides, and graphite, and conductive polymers. Examples of the conductive polymer include polyacetylene. Examples of the non-conductive substance include silica, alumina, barium titanate, zirconia, and the like. Among them, metal is preferable because conductivity can be increased and connection resistance can be effectively reduced. The core substance is preferably metal particles.

  Examples of the metal include gold, silver, copper, platinum, zinc, iron, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium and cadmium, and tin-lead. Examples include alloys composed of two or more metals such as alloys, tin-copper alloys, tin-silver alloys, tin-lead-silver alloys, and tungsten carbide.

  The material of the core substance is preferably an inorganic substance that does not contain nickel. However, the core material may be nickel. Specific examples of the core material include titanium oxide (Mohs hardness 4), barium titanate (Mohs hardness 4.5), nickel (Mohs hardness 5), silica (silicon dioxide, Mohs hardness 6-7), zirconia. (Mohs hardness 8-9), alumina (Mohs hardness 9), tungsten carbide (Mohs hardness 9), diamond (Mohs hardness 10), and the like. The material of the core substance is preferably titanium oxide, barium titanate, nickel, silica, zirconia, alumina, tungsten carbide or diamond, and more preferably nickel, silica, zirconia, alumina, tungsten carbide or diamond. More preferably, zirconia, alumina, tungsten carbide or diamond. From the viewpoint of further lowering the initial connection resistance, the Mohs hardness of the material of the core substance is preferably larger than that of silver and more preferably larger than that of copper. When the first conductive layer is a silver layer, the material of the core material preferably has a Mohs hardness greater than that of silver, and when the first conductive layer is a copper layer, the core More preferably, the material material has a Mohs hardness greater than that of copper. From the viewpoint of further reducing the initial connection resistance, the Mohs hardness of the material of the core substance is preferably 4 or more, more preferably 5.5 or more, still more preferably 6 or more, and particularly preferably 7.5 or more. . From the viewpoint of further suppressing an increase in connection resistance in the presence of an acid, the core material is preferably formed of an inorganic material that does not contain a metal.

  From the viewpoint of effectively reducing the connection resistance between the electrodes, the Mohs hardness of the material of the core substance is preferably equal to or higher than the Mohs hardness (5) of nickel, and is larger than the Mohs hardness of nickel. preferable. The absolute value of the difference between the Mohs hardness of the core material and the Mohs hardness of nickel is preferably 0.1 or more, more preferably 0.2 or more, still more preferably 0.5 or more, and particularly preferably 1 or more. Most preferably, it is 2 or more. The material of the core substance is a main material (50% by weight or more) constituting the core substance, and is the material most contained in the core substance.

  The shape of the core material is not particularly limited. The shape of the core substance is preferably a lump. Examples of the core substance include a particulate lump, an agglomerate in which a plurality of fine particles are aggregated, and an irregular lump.

  The average diameter (average particle diameter) of the core substance 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 diameter of the core substance is not less than the above lower limit and not more than the above upper limit, the connection resistance between the electrodes is effectively reduced.

  The “average diameter (average particle diameter)” of the core substance indicates a number average diameter (number average particle diameter). The average diameter of the core material is obtained by observing 50 arbitrary core materials with an electron microscope or an optical microscope and calculating an average value.

[Insulating material]
The conductive particles according to the present invention preferably include an insulating substance disposed on the outer surface of the conductive layer. In this case, when the conductive particles are used for connection between the electrodes, a short circuit between adjacent electrodes can be prevented. Specifically, when a plurality of conductive particles are in contact with each other, an insulating material is present between the plurality of electrodes, so that it is possible to prevent a short circuit between electrodes adjacent in the lateral direction instead of between the upper and lower electrodes. Note that when the conductive particles are pressurized with the two electrodes at the time of connection between the electrodes, the insulating substance between the conductive layer of the conductive particles and the electrodes can be easily excluded. When the conductive particles have a plurality of protrusions on the outer surface of the conductive layer, the insulating material between the conductive layer of the conductive particles and the electrode can be easily excluded.

  It is preferable that the insulating material is an insulating particle because the insulating material can be more easily removed when the electrodes are pressed.

  Specific examples of the insulating resin that is the material of the insulating material include polyolefins, (meth) acrylate polymers, (meth) acrylate copolymers, block polymers, thermoplastic resins, crosslinked thermoplastic resins, and thermosetting. Resin, water-soluble resin, and the like.

  Examples of the polyolefins include polyethylene, ethylene-vinyl acetate copolymer, and ethylene-acrylic acid ester copolymer. Examples of the (meth) acrylate polymer include polymethyl (meth) acrylate, polyethyl (meth) acrylate, and polybutyl (meth) acrylate. Examples of the block polymer include polystyrene, styrene-acrylic acid ester copolymer, SB type styrene-butadiene block copolymer, SBS type styrene-butadiene block copolymer, and hydrogenated products thereof. Examples of the thermoplastic resin include vinyl polymers and vinyl copolymers. As said thermosetting resin, an epoxy resin, a phenol resin, a melamine resin, etc. are mentioned. Examples of the water-soluble resin include polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinyl pyrrolidone, polyethylene oxide, and methyl cellulose. Of these, water-soluble resins are preferable, and polyvinyl alcohol is more preferable.

  Examples of a method for disposing an insulating material on the surface of the conductive layer include a chemical method and a physical or mechanical method. Examples of the chemical method include an interfacial polymerization method, a suspension polymerization method in the presence of particles, and an emulsion polymerization method. Examples of the physical or mechanical method include spray drying, hybridization, electrostatic adhesion, spraying, dipping, and vacuum deposition. In particular, since the insulating substance is difficult to be detached, a method of disposing the insulating substance on the surface of the conductive layer through a chemical bond is preferable.

  Each of the outer surface of the conductive layer and the surface of the insulating particles may be coated with a compound having a reactive functional group. The outer surface of the conductive layer and the surface of the insulating particles may not be directly chemically bonded, but may be indirectly chemically bonded by a compound having a reactive functional group. After introducing a carboxyl group into the outer surface of the conductive layer, the carboxyl group may be chemically bonded to a functional group on the surface of the insulating particle through a polymer electrolyte such as polyethyleneimine.

  The average diameter (average particle diameter) of the insulating material can be appropriately selected depending on the particle diameter of the conductive particles, the use of the conductive particles, and the like. The average diameter (average particle diameter) of the insulating material is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 1 μm or less, more preferably 0.5 μm or less. When the average diameter of the insulating material is not less than the above lower limit, the conductive layers of the plurality of conductive particles are difficult to contact when the conductive particles are dispersed in the binder resin. When the average diameter of the insulating particles is not more than the above upper limit, it is not necessary to make the pressure too high in order to eliminate the insulating material between the electrodes and the conductive particles when the electrodes are connected. There is no need for heating.

  The “average diameter (average particle diameter)” of the insulating material indicates a number average diameter (number average particle diameter). The average diameter of the insulating material is obtained using a particle size distribution measuring device or the like.

[Rust prevention treatment]
From the viewpoint of suppressing the corrosion of the conductive particles and further reducing the connection resistance between the electrodes, the outer surface of the second conductive layer is preferably rust-proofed.

  From the viewpoint of further improving the conduction reliability, the outer surface of the second conductive layer is preferably subjected to a rust prevention treatment with a compound having an alkyl group having 6 to 22 carbon atoms. From the viewpoint of further improving the conduction reliability, the outer surface of the second conductive layer is preferably rust-proofed with an alkyl phosphate compound or an alkyl thiol. By the rust prevention treatment, a rust prevention film can be formed on the surface of the second conductive layer.

  The rust preventive film is preferably formed of a compound having an alkyl group having 6 to 22 carbon atoms (hereinafter also referred to as compound A). The outer surface of the second conductive layer is preferably surface-treated with the compound A. When the carbon number of the alkyl group is 6 or more, rust is more unlikely to occur on the outer surface of the second conductive layer. When the carbon number of the alkyl group is 22 or less, the conductivity of the conductive particles is increased. From the viewpoint of further improving the conductivity of the conductive particles, the alkyl group in the compound A preferably has 16 or less carbon atoms. The alkyl group may have a linear structure or a branched structure. The alkyl group preferably has a linear structure.

  The compound A is not particularly limited as long as it has an alkyl group having 6 to 22 carbon atoms. The compound A has a phosphate ester having an alkyl group having 6 to 22 carbon atoms or a salt thereof, a phosphite ester having an alkyl group having 6 to 22 carbon atoms or a salt thereof, and an alkyl group having 6 to 22 carbon atoms. It is preferably at least one selected from the group consisting of alkoxysilanes, alkylthiols having an alkyl group having 6 to 22 carbon atoms, and dialkyl disulfides having an alkyl group having 6 to 22 carbon atoms. That is, the compound A having an alkyl group having 6 to 22 carbon atoms is at least one selected from the group consisting of phosphate esters or salts thereof, phosphite esters or salts thereof, alkoxysilanes, alkylthiols, and dialkyl disulfides. It is preferable that By using these preferable compounds A, it is possible to further prevent rust from being generated in the second conductive layer. From the viewpoint of making rust even more difficult to generate, the compound A is preferably the phosphate ester or salt thereof, phosphite ester or salt thereof, or alkylthiol, and the phosphate ester or salt thereof, Or it is more preferable that it is a phosphite ester or its salt. As for the said compound A, only 1 type may be used and 2 or more types may be used together.

  The compound A preferably has a reactive functional group capable of reacting with the outer surface of the second conductive layer. The compound A preferably has a reactive functional group capable of reacting with the insulating substance. The rust preventive film is preferably chemically bonded to the second conductive layer. The rust preventive film is preferably chemically bonded to the insulating substance. More preferably, the rust preventive film is chemically bonded to both the second conductive layer and the insulating material. Due to the presence of the reactive functional group and due to the chemical bond, the rust preventive film is less likely to be peeled off. As a result, rust is less likely to occur in the second conductive layer, and from the surface of the conductive particles. The insulating material is more difficult to be detached unintentionally.

  Examples of the phosphoric acid ester having an alkyl group having 6 to 22 carbon atoms or a salt thereof include, for example, phosphoric acid hexyl ester, phosphoric acid heptyl ester, phosphoric acid monooctyl ester, phosphoric acid monononyl ester, phosphoric acid monodecyl ester, Monoundecyl phosphate, monododecyl phosphate, monotridecyl phosphate, monotetradecyl phosphate, monopentadecyl phosphate, monohexyl phosphate monosodium salt, monoheptyl phosphate monosodium Salts, monooctyl phosphate monosodium salt, monononyl phosphate monosodium salt, monodecyl phosphate monosodium salt, monoundecyl phosphate monosodium salt, monododecyl phosphate monosodium salt, Phosphate mono tridecyl ester monosodium salt, phosphate acid mono tetradecyl ester monosodium salt and phosphoric acid mono pentadecyl ester monosodium salt. You may use the potassium salt of the said phosphate ester.

  Examples of the phosphite ester having an alkyl group having 6 to 22 carbon atoms or a salt thereof include, for example, hexyl phosphite ester, heptyl phosphite ester, monooctyl phosphite ester, monononyl phosphite ester, Phosphoric acid monodecyl ester, phosphorous acid monoundecyl ester, phosphorous acid monododecyl ester, phosphorous acid monotridecyl ester, phosphorous acid monotetradecyl ester, phosphorous acid monopentadecyl ester, phosphorous acid monohexyl Ester monosodium salt, phosphorous acid monoheptyl ester monosodium salt, phosphorous acid monooctyl ester monosodium salt, phosphorous acid monononyl ester monosodium salt, phosphorous acid monodecyl ester monosodium salt, phosphorous acid monoun Decyl ester monosodium salt, phosphorous acid Dodecyl ester monosodium salt, phosphorous acid mono-tridecyl ester monosodium salt, phosphorous acid mono-tetradecyl ester monosodium salt and phosphorous acid mono-pentadecyl ester monosodium salt. You may use the potassium salt of the said phosphite.

  Examples of the alkoxysilane having an alkyl group having 6 to 22 carbon atoms include hexyltrimethoxysilane, hexyltriethoxysilane, heptyltrimethoxysilane, heptyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, and nonyltri. Methoxysilane, nonyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, undecyltrimethoxysilane, undecyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, tridecyltrimethoxysilane, tridecyltriethoxy Examples include silane, tetradecyltrimethoxysilane, tetradecyltriethoxysilane, pentadecyltrimethoxysilane, and pentadecyltriethoxysilane.

  Examples of the alkyl thiol having an alkyl group having 6 to 22 carbon atoms include hexyl thiol, heptyl thiol, octyl thiol, nonyl thiol, decyl thiol, undecyl thiol, dodecyl thiol, tridecyl thiol, tetradecyl thiol, pentadecyl. Examples include thiol and hexadecyl thiol. The alkyl thiol preferably has a thiol group at the end of the alkyl chain.

  Examples of the dialkyl disulfide having an alkyl group having 6 to 22 carbon atoms include dihexyl disulfide, diheptyl disulfide, dioctyl disulfide, dinonyl disulfide, didecyl disulfide, diundecyl disulfide, didodecyl disulfide, ditridecyl disulfide, ditetradecyl disulfide. Examples include decyl disulfide, dipentadecyl disulfide, and dihexadecyl disulfide.

(Conductive material)
The conductive material according to the present invention includes the conductive particles described above and a binder resin. The conductive particles are preferably dispersed in a binder resin and used as a conductive material. The conductive material is preferably an anisotropic conductive material. The conductive particles and the conductive material are each preferably a circuit connection material.

  The binder resin is not particularly limited. As the binder resin, a known insulating resin is used.

  Examples of the binder resin include vinyl resins, thermoplastic resins, curable resins, thermoplastic block copolymers, and elastomers. As for the said binder resin, only 1 type may be used and 2 or more types may be used together.

  Examples of the vinyl resin include vinyl acetate resin, acrylic resin, and styrene resin. Examples of the thermoplastic resin include polyolefin resins, ethylene-vinyl acetate copolymers, and polyamide resins. Examples of the curable resin include an epoxy resin, a urethane resin, a polyimide resin, and an unsaturated polyester resin. The curable resin may be a room temperature curable resin, a thermosetting resin, a photocurable resin, or a moisture curable resin. The curable resin may be used in combination with a curing agent. Examples of the thermoplastic block copolymer include a styrene-butadiene-styrene block copolymer, a styrene-isoprene-styrene block copolymer, a hydrogenated product of a styrene-butadiene-styrene block copolymer, and a styrene-isoprene. -Hydrogenated product of a styrene block copolymer. 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 colorant, an antioxidant, a heat stabilizer, and a light stabilizer. Various additives such as an agent, an ultraviolet absorber, a lubricant, an antistatic agent and a flame retardant may be contained.

  The conductive material according to the present invention can be used as a conductive paste and a conductive film. When the conductive material according to the present invention is a conductive film, a film that does not include conductive particles may be laminated on a conductive film that includes conductive particles. The conductive paste is preferably an anisotropic conductive paste. The conductive film is preferably an anisotropic conductive film.

  In 100% by weight of the conductive material, the content of the binder resin is preferably 10% by weight or more, more preferably 30% by weight or more, still more preferably 50% by weight or more, particularly preferably 70% by weight or more, preferably 99.% or more. It is 99 weight% or less, More preferably, it is 99.9 weight% or less. When the content of the binder resin is not less than the above lower limit and not more than the above upper limit, the conductive particles are efficiently arranged between the electrodes, and the connection reliability of the connection target member connected by the conductive material is further increased.

  In 100% by weight of the conductive material, the content of the conductive particles is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, preferably 80% by weight or less, more preferably 60% by weight or less, More preferably, it is 40% by weight or less, further preferably 20% by weight or less, and particularly preferably 10% by weight or less. When the content of the conductive particles is not less than the above lower limit and not more than the above upper limit, the conduction reliability between the electrodes is further enhanced.

(Connection structure)
A connection structure can be obtained by connecting the connection object members using the conductive particles or using a conductive material containing the conductive particles and a binder resin.

  The connection structure includes a first connection target member, a second connection target member, and a connection portion connecting the first and second connection target members, and the connection portion has the above-described conductivity. The connection structure is preferably formed of particles or formed of a conductive material containing the above-described conductive particles and a binder resin. In the case where conductive particles are used, the connection portion itself is conductive particles. That is, the first and second connection target members are connected by the conductive particles.

  In FIG. 6, the connection structure using the electroconductive particle which concerns on the 1st Embodiment of this invention is typically shown with sectional drawing.

  The connection structure 51 shown in FIG. 6 includes a first connection target member 52, a second connection target member 53, and a connection portion 54 connecting the first and second connection target members 52 and 53. Prepare. The connection portion 54 is formed by curing a conductive material including the conductive particles 1. In FIG. 6, the conductive particles 1 are schematically shown for convenience of illustration. Instead of the conductive particles 1, conductive particles 1A, 1B, 1C, 1D and the like may be used.

  The first connection target member 52 has a plurality of first electrodes 52a on the surface (upper surface). The second connection target member 53 has a plurality of second electrodes 53a on the surface (lower surface). The first electrode 52 a and the second electrode 53 a are electrically connected by one or a plurality of conductive particles 1. Therefore, the first and second connection target members 52 and 53 are electrically connected by the conductive particles 1.

The manufacturing method of the connection structure is not particularly limited. As an example of the manufacturing method of the connection structure, the conductive material is disposed between the first connection target member and the second connection target member to obtain a laminate, and then the laminate is heated and pressurized. Methods and the like. The pressure of the pressurization is about 9.8 × 10 ^{4 to} 4.9 × 10 ⁶ Pa. The temperature of the said heating is about 120-220 degreeC.

  Specific examples of the connection target member include electronic components such as semiconductor chips, capacitors, and diodes, and electronic components such as printed boards, flexible printed boards, glass epoxy boards, and glass boards. The connection target member is preferably an electronic component. The conductive particles are preferably used for electrical connection of electrodes in an electronic component.

  Examples of the electrode provided on the connection target member include metal electrodes such as a gold electrode, a nickel electrode, a tin electrode, an aluminum electrode, a copper electrode, a silver electrode, a molybdenum electrode, and a tungsten electrode. When the connection object member is a flexible printed board, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, or a copper electrode. When the connection target member is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode, or a tungsten electrode. In addition, when the said electrode is an aluminum electrode, the electrode formed only with aluminum may be sufficient and the electrode by which the aluminum layer was laminated | stacked on the surface of the metal oxide layer may be sufficient. Examples of the material for the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal element include Sn, Al, and Ga.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The present invention is not limited only to the following examples.

Example 1
The surface of divinylbenzene copolymer resin particles (“Micropearl SP-203” manufactured by Sekisui Chemical Co., Ltd.) having a particle size of 3.0 μm is made of silica (inorganic shell, thickness 250 nm) using a condensation reaction by sol-gel reaction. Coated core-shell type organic-inorganic hybrid particles (base particle A, 10% K value: 8500 mN / mm ² ) were prepared.

  The organic / inorganic hybrid particles were etched and washed with water. Next, organic-inorganic hybrid particles were added to 100 mL of a palladium-catalyzed solution containing 8% by weight of a palladium catalyst and stirred. Then, it filtered and wash | cleaned. Organic / inorganic hybrid particles were added to 0.5 wt% dimethylamine borane solution at pH 6 to obtain organic / inorganic hybrid particles to which palladium was attached.

  The organic-inorganic hybrid particles to which palladium was attached were stirred and dispersed in 300 mL of ion exchange water for 3 minutes to obtain a dispersion. Next, 1 g of silica particle slurry (average particle diameter of silica as a core material of 100 nm) was added to the dispersion over 3 minutes to obtain organic-inorganic hybrid particles to which the core material was adhered.

  A copper layer (thickness X 40 nm) was formed on the surface of the organic-inorganic hybrid particles by performing electroless copper plating using the organic-inorganic hybrid particles to which the core substance was attached.

  Next, by performing an electroless nickel plating process using an inorganic electrolytic nickel plating solution containing nickel sulfate, sodium tungstate, and dimethylamine borane as a reducing agent, a nickel layer (thickness) is formed on the outer surface of the copper layer. Y80 nm). In this way, conductive particles were obtained. The thickness A of the nickel layer in the portion without protrusions in the obtained conductive particles was 80 nm, and the average height B of the protrusions was 100 nm. The number of protrusions was 75.

(Example 2)
Divinylbenzene copolymer resin particles having a particle size of 3.5 μm (base particle B, “Micropearl SP-203” manufactured by Sekisui Chemical Co., Ltd., 10% K value: 7000 mN / mm ² ) were prepared. The number of protrusions was 75.

  Conductive particles were obtained in the same manner as in Example 1 except that the base particles were changed to the resin particles.

(Example 3)
When forming the copper layer, conductive particles were obtained in the same manner as in Example 1 except that the copper plating solution used for the electroless copper plating treatment was changed to a copper plating solution containing sodium titanate.

Example 4
When forming the nickel layer, conductive particles were obtained in the same manner as in Example 1 except that an electroless nickel plating solution containing nickel sulfate, sodium molybdate and dimethylamine borane as a reducing agent was used. .

(Example 5)
Conductive particles were obtained in the same manner as in Example 1 except that the thickness Y of the nickel layer and the thickness A of the nickel layer where no protrusion was formed were changed to 50 nm.

(Example 6)
Conductive particles were obtained in the same manner as in Example 1 except that the thickness Y of the nickel layer and the thickness A of the nickel layer where no protrusion was formed were changed to 95 nm.

(Example 7)
Conductive particles were obtained in the same manner as in Example 1 except that the thickness X of the copper layer was changed to 5 nm.

(Example 8)
Conductive particles were obtained in the same manner as in Example 1 except that the thickness X of the copper layer was changed to 10 nm.

Example 9
Conductive particles were obtained in the same manner as in Example 1 except that the thickness X of the copper layer was changed to 300 nm.

(Example 10)
Conductive particles were obtained in the same manner as in Example 1 except that the average particle diameter of the core substance contained in the silica particle slurry was changed to 240 nm and the average height B of the protrusions was changed to 240 nm.

(Example 11)
Conductive particles were obtained in the same manner as in Example 1 except that the average particle diameter of the core substance contained in the silica particle slurry was changed to 300 nm and the average height B of the protrusions was changed to 300 nm.

(Example 12)
Conductive particles were obtained in the same manner as in Example 1 except that the silica particle slurry was changed to nickel particle slurry (average particle diameter of nickel as the core material of 100 nm).

(Example 13)
The organic-inorganic hybrid particles of Example 1 were used. Conductive particles were obtained in the same manner as in Example 1 except that the protrusions were not formed using the organic-inorganic hybrid particles to which the silica particle slurry was not attached.

(Example 14)
To a 1000 mL separable flask equipped with a four-neck separable cover, stirring blade, three-way cock, condenser and temperature probe, 100 mmol of methyl methacrylate and N, N, N-trimethyl-N-2-methacryloyloxyethyl A monomer composition containing 1 mmol of ammonium chloride and 1 mmol of 2,2′-azobis (2-amidinopropane) dihydrochloride was weighed in ion-exchanged water so that the solid content was 5% by weight, and then at 200 rpm. The mixture was stirred and polymerized at 70 ° C. for 24 hours under a nitrogen atmosphere. After completion of the reaction, it was freeze-dried to obtain insulating particles having an ammonium group on the surface, an average particle size of 220 nm, and a CV value of 10%.

  The insulating particles were dispersed in ion exchange water under ultrasonic irradiation to obtain a 10 wt% aqueous dispersion of insulating particles.

  10 g of the conductive particles obtained in Example 1 were dispersed in 500 mL of ion exchange water, 4 g of an aqueous dispersion of insulating particles was added, and the mixture was stirred at room temperature for 6 hours. After filtration through a 3 μm mesh filter, the particles were further washed with methanol and dried to obtain conductive particles having insulating particles attached thereto.

  When observed with a scanning electron microscope (SEM), only one coating layer of insulating particles was formed on the surface of the conductive particles. The coverage of the insulating particles with respect to the area of 2.5 μm from the center of the conductive particles by image analysis (that is, the projected area of the particle diameter of the insulating particles) was calculated to be 30%.

(Comparative Example 1)
Conductive particles were obtained in the same manner as in Example 1 except that the nickel layer was not formed, that is, only the copper layer was formed on the surface of the organic-inorganic hybrid particles.

(Comparative Example 2)
Conductive particles were obtained in the same manner as in Example 1 except that the copper layer was not formed, that is, only the nickel layer was formed on the surface of the organic-inorganic hybrid particles.

(Comparative Example 3)
Conductive particles were obtained in the same manner as in Example 2 except that the nickel layer was not formed, that is, only the copper layer was formed on the surface of the resin particles.

(Comparative Example 4)
Conductive particles were obtained in the same manner as in Example 2 except that the copper layer was not formed, that is, only the nickel layer was formed on the surface of the resin particles.

(Comparative Example 5)
Conductive particles were formed in the same manner as in Example 1 except that when forming the nickel layer, an electroless nickel plating solution containing nickel sulfate and dimethylamine borane as a reducing agent and not containing sodium tungstate was used. Got.

(Comparative Example 6)
Conductive particles were formed in the same manner as in Example 2 except that when forming the nickel layer, an electroless nickel plating solution containing nickel sulfate and dimethylamine borane as a reducing agent and not containing sodium tungstate was used. Got.

(Example 15)
A core-shell type organic material in which the surface of a divinylbenzene copolymer resin particle having a particle diameter of 1.75 μm is coated with silica (inorganic shell, thickness 250 nm) using a condensation reaction by a sol-gel reaction instead of the base particle A Conductive particles were obtained in the same manner as in Example 1 except that inorganic hybrid particles (base particle C, 10% K value: 6000 mN / mm ² ) were used. The number of protrusions was 40.

(Example 16)
A core-shell type organic material in which the surface of divinylbenzene copolymer resin particles having a particle size of 9.5 μm is coated with silica (inorganic shell, thickness 250 nm) using a condensation reaction by a sol-gel reaction instead of the base particle A Conductive particles were obtained in the same manner as in Example 1 except that inorganic hybrid particles (base particle D, 10% K value: 4500 mN / mm ² ) were used. The number of protrusions was 750.

(Example 17)
Conductive particles obtained by dispersing conductive particles obtained in Example 1 (before rust prevention treatment) in 2-ethylhexyl azide phosphate, and then removing the conductive particles, whereby the outer surface is subjected to rust prevention treatment. Particles were obtained.

(Example 18)
Conductive particles were obtained in the same manner as in Example 1 except that the content of tungsten in the nickel plating layer in the obtained conductive particles was changed to 5% by weight.

(Example 19)
Conductive particles were obtained in the same manner as in Example 1 except that the content of tungsten in the nickel plating layer in the obtained conductive particles was changed to 0.1% by weight.

(Example 20)
Conductive particles were obtained in the same manner as in Example 1 except that the content of tungsten in the nickel plating layer in the obtained conductive particles was changed to 5.5% by weight.

(Example 21)
Conductive particles were obtained in the same manner as in Example 1 except that the content of tungsten in the nickel plating layer in the obtained conductive particles was changed to 0.05% by weight.

(Evaluation)
(0) Protrusion State Using a scanning electron microscope (SEM), the image magnification is 25000 times for particles with a particle size of less than 4 μm, 8000 times for particles with a particle size of 4 μm or more and less than 8 μm, In the case of particles having a particle size of 8 μm or more, the particle size was set to 3000 times, 10 conductive particles were randomly selected, and the protrusions of the respective conductive particles were observed. The number of protrusions was measured.

(1) Content of copper in 100% by weight of copper layer and content of nickel, boron or phosphorus, and tungsten or molybdenum in 100% by weight of nickel layer The particle cross section was measured using “FIB (SMI500)” manufactured by SII. Cut out and analyzed by EDS line analysis using “FE-TEM (JEM-2010FEF)” manufactured by JEOL Ltd., and each content of copper, nickel, boron or phosphorus, and tungsten or molybdenum was measured.

(2) Initial connection resistance A
Fabrication of connection structure:
It was left to stand for 100 hours in the obtained constant temperature and humidity chamber of 85 ° C. and humidity of 85%. Using the conductive particles after standing, an anisotropic conductive paste was obtained as follows.

  20 parts by weight of an epoxy compound that is a thermosetting compound (“EP-3300P” manufactured by Nagase ChemteX), 15 parts by weight of an epoxy compound that is a thermosetting compound (“EPICLON HP-4032D” manufactured by DIC), and heat It was obtained by blending 5 parts by weight of a thermal cation generator (San-Aid “SI-60” manufactured by Sanshin Chemical Co., Ltd.) as a curing agent and 20 parts by weight of silica (average particle diameter of 0.25 μm) as a filler. After the conductive particles were added so that the content in the blend of 100% by weight was 10% by weight, the anisotropic conductive paste was obtained by stirring at 2000 rpm for 5 minutes using a planetary stirrer.

  A glass substrate having an Al—Ti 4% electrode pattern (Al—Ti 4% electrode thickness 1 μm) having an L / S of 20 μm / 20 μm on the upper surface was prepared. A semiconductor chip having a gold electrode pattern (gold electrode thickness 20 μm) with L / S of 20 μm / 20 μm on the lower surface was prepared.

  On the upper surface of the glass substrate, the anisotropic conductive paste immediately after fabrication was applied to a thickness of 20 μm to form an anisotropic conductive material layer. Next, the semiconductor chip was stacked on the upper surface of the anisotropic conductive material layer so that the electrodes face each other. Then, while adjusting the temperature of the head so that the temperature of the anisotropic conductive material layer becomes 170 ° C., a pressure heating head is placed on the upper surface of the semiconductor chip and a pressure of 3.0 MPa is applied to apply the anisotropic conductive material. The material layer was cured at 170 ° C. to obtain a connection structure.

Connection resistance measurement:
The connection resistance between the opposing electrodes of the obtained connection structure was measured by the 4-terminal method. The initial connection resistance A was determined according to the following criteria.

[Evaluation criteria for initial connection resistance A]
○○○: Connection resistance is 2.0Ω or less ○○: Connection resistance is over 2.0Ω, 3.0Ω or less ○: Connection resistance is over 3.0Ω, 5.0Ω or less Δ: Connection resistance is 5.0Ω 10Ω or less △△: Connection resistance exceeds 10Ω, 15Ω or less ×: Connection resistance exceeds 15Ω

(3) Connection resistance B after being exposed to the presence of acid
The connection structure obtained by the above (2) evaluation of the initial connection resistance A was left for 100 hours in a constant temperature and humidity chamber at 85 ° C. and a humidity of 85%. By leaving the connection structure under the above-described conditions, the connection portion between the electrodes in the connection structure is exposed to the presence of acid for a certain period due to the reaction between the water that has entered the binder resin and the acid contained in the binder resin. It was done. In the connection structure after being left, the connection resistance between the opposing electrodes of the connection structure was measured by a four-terminal method. Moreover, the connection resistance B after being exposed to the presence of an acid was determined according to the following criteria.

[Evaluation criteria for connection resistance B after exposure to acid]
○ ○ ○: Connection resistance B is less than 1 time of connection resistance A ○ ○: Connection resistance B is 1 time or more and less than 1.5 times of connection resistance A ○: Connection resistance B is 1.5 times or more of connection resistance A Less than 2 times Δ: Connection resistance B is 2 times or more and less than 5 times connection resistance A ΔΔ: Connection resistance B is 5 times or more and less than 10 times connection resistance A ×: Connection resistance B is 10 times connection resistance A More than double

  The results are shown in Table 1 below.

  Regarding the variation in connection resistance among the plurality of connection structures, the connection structure using the conductive particles of Examples 1 to 10 and 12 to 21 is more than the connection structure using the conductive particles of Example 11. Was also small. This is considered that the variation in connection resistance occurred in Example 11 because the average height B / thickness A was relatively large.

  In addition, although the specific Example which formed the copper layer was shown, even when it forms a silver layer instead of a copper layer, the reduction effect of the initial connection resistance and the increase suppression effect of the connection resistance in presence of an acid are shown. It was confirmed that However, when the copper layer was formed, the effect of reducing the initial connection resistance and the effect of suppressing the increase of the connection resistance in the presence of acid were greater than when the silver layer was formed.

1, 1A, 1B, 1C, 1D ... conductive particles 1a, 1Aa, 1Ba, 1Ca ... projections 11 ... substrate particles 12, 12A, 12B, 12D ... first conductive layers 12a, 12Aa ... projections 13, 13B, 13D ... 2nd conductive layer 13a, 13Ba ... Projection 14 ... Core material 15 ... Insulating material 21 ... Base material particle 21X ... Core 22Y ... Shell 51 ... Connection structure 52 ... 1st connection object member 52a ... 1st electrode 53 ... 2nd connection object member 53a ... 2nd electrode 54 ... Connection part

Claims (13)

Substrate particles,
A first conductive layer disposed on the surface of the substrate particles and formed of silver or copper;
A second conductive layer disposed on the outer surface of the first conductive layer and formed of nickel,
Conductive particles in which the second conductive layer includes nickel, boron, and tangsten or molybdenum.   The electroconductive particle of Claim 1 whose content of nickel in a said 2nd conductive layer is 50 to 99 weight%.   The conductive particles according to claim 1 or 2, wherein the content of tungsten or molybdenum in the second conductive layer is 0.1 wt% or more and 5.0 wt% or less.   4. The conductive particle according to claim 1, wherein a content of boron in the second conductive layer is 0.1 wt% or more and 5.0 wt% or less.   5. The conductive particle according to claim 1, wherein the second conductive layer has a plurality of protrusions on an outer surface.   The conductive particles according to any one of claims 1 to 5, wherein the thickness of the second conductive layer is 0.1 to 10 times the thickness of the first conductive layer.   The electroconductive particle of any one of Claims 1-6 whose said 1st conductive layer is a copper layer formed with copper.   The electroconductive particle of any one of Claims 1-7 whose said base material particle is a resin particle or an organic inorganic hybrid particle.   The electroconductive particle of Claim 8 whose said base material particle is the said organic-inorganic hybrid particle.   The electroconductive particle of any one of Claims 1-9 by which the outer surface of the said 2nd conductive layer is rust-proofed.   The electroconductive particle of any one of Claims 1-10 further provided with the insulating substance arrange | positioned on the outer surface of a said 2nd conductive layer.   The electroconductive material containing the electroconductive particle of any one of Claims 1-11, and binder resin. A first connection object member having a first electrode on its surface;
A second connection target member having a second electrode on its surface;
A connection portion connecting the first connection target member and the second connection target member;
The connection portion is formed of the conductive particles according to any one of claims 1 to 11, or is formed of a conductive material including the conductive particles and a binder resin.
A connection structure in which the first electrode and the second electrode are electrically connected by the conductive particles.

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