JP6523860B2 - Conductive particle, conductive material and connection structure - Google Patents

Description

  The present invention relates to a conductive particle comprising a substrate particle and a conductive portion disposed on the surface of the substrate particle, wherein the conductive portion has a plurality of protrusions on the outer surface. The present invention also relates to a conductive material and a connecting structure using the above-described conductive particles.

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

  The anisotropic conductive material is, for example, a connection between a flexible printed substrate and a glass substrate (FOG (Film on Glass)) and a connection between a semiconductor chip and a flexible printed substrate (COF (COF) to obtain various connection structures. It is used for chip on film), connection between semiconductor chip and glass substrate (COG (chip on glass)), connection between flexible printed circuit board and glass epoxy substrate (FOB (film on board)), and the like. Moreover, the electroconductive particle which has a base material particle and the electroconductive part arrange | positioned on the surface of this base material particle may be used as said electroconductive particle.

  As an example of the conductive particles, Patent Document 1 below discloses conductive particles having a core material particle (base material particle) and a film of a metal or an alloy on the surface of the core material particle. . The conductive particle has a plurality of protrusions projecting from the surface of the film. The said projection part is comprised from the particle | grain connection body which several particle | grains of the metal or the alloy connected in line form. In the example and comparative example of patent document 1, the electroconductive particle whose ratio of a connection protrusion part is 32% or more is shown.

JP, 2012-113850, A

  In recent years, it has been required to reduce the power consumption of electronic devices. For this reason, the conductive particles are required to have a property capable of further reducing the connection resistance between the electrodes electrically connected by the conductive particles.

  However, when the electrodes are electrically connected using the conventional conductive particles as described in Patent Document 1, the connection resistance may be high.

  An object of the present invention is to provide a conductive particle which can reduce connection resistance when the electrodes are electrically connected. Another object of the present invention is to provide a conductive material and a connection structure using the above-mentioned conductive particles.

  According to a broad aspect of the present invention, a substrate particle and a conductive portion disposed on the surface of the substrate particle, the conductive portion having a plurality of projections on the outer surface, and the plurality of projections A conductive particle is provided in which the proportion of protrusions having an aspect ratio of 2 or more and 4 or less in a total number of 100% is 20% or more.

  In a specific aspect of the conductive particle according to the present invention, the proportion of projections having an aspect ratio of 3 or more and 4 or less is 10% or more in 100% of the total number of the plurality of projections.

  In a specific aspect of the conductive particles according to the present invention, the percentage of protrusions having an aspect ratio of 2 or more and 4 or less is 30% or more in 100% of the total number of the plurality of protrusions.

  In a specific aspect of the conductive particle according to the present invention, the plurality of protrusions includes a protrusion formed by connecting a plurality of particles in a row.

  In a specific aspect of the conductive particle according to the present invention, the protrusion formed by connecting a plurality of the particles in a row has a bent portion on the outer peripheral surface.

  In a specific aspect of the conductive particle according to the present invention, the material of the outer surface of the plurality of protrusions includes nickel.

  In a specific aspect of the conductive particle according to the present invention, the conductive portion includes a first conductive portion and a second conductive portion disposed on the outer surface of the first conductive portion. At least one of the first conductive portion and the second conductive portion is a conductive portion containing nickel and having a crystal structure.

  In a specific aspect of the conductive particle according to the present invention, in the conductive portion containing nickel and having a crystal structure, the ratio of (111) plane in X-ray diffraction is 80% or more.

  In a specific aspect of the conductive particle according to the present invention, the conductive particle comprises a core substance disposed on the surface of the base particle, and covers the base particle and the core substance. The conductive portion is disposed on the surface of the base particle, the core substance is disposed inside the plurality of protrusions, and the core substance contains no metal, or The main metal contained is different from the main metal contained in the conductive portion in contact with the core material.

  In a specific aspect of the conductive particles according to the present invention, the material of the core material has a Mohs hardness of 5 or more.

  In a specific aspect of the conductive particle according to the present invention, an average height of the plurality of protrusions is 50 nm or more and 900 nm or less.

  In a specific aspect of the conductive particle according to the present invention, the surface area of the portion with the protrusion is 30% or more in 100% of the total surface area of the outer surface of the conductive portion.

  In a specific aspect of the conductive particle according to the present invention, the substrate particle is a resin particle or an organic-inorganic hybrid particle.

  In one particular aspect of the conductive particle according to the present invention, the conductive particle comprises an insulating material disposed on the outer surface of the conductive part.

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

  According to a broad 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 first connection target member A connecting portion connecting the second connection target member, and a material of the connecting portion is the above-described conductive particle, or a conductive material including the conductive particle and a binder resin, A connection structure is provided in which the first electrode and the second electrode are electrically connected by the conductive particles.

  The conductive particle according to the present invention comprises a substrate particle and a conductive portion disposed on the surface of the substrate particle, wherein the conductive portion has a plurality of protrusions on the outer surface, and the plurality of protrusions Since the ratio of projections having an aspect ratio of 2 to 4 in the total number of 100% is 20% or more, connection resistance when electrodes are electrically connected using the conductive particles according to the present invention Can be lowered.

FIG. 1 is a cross-sectional view showing a conductive particle according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a conductive particle according to a second embodiment of the present invention. FIG. 3 is a cross-sectional view showing a conductive particle according to a third embodiment of the present invention. FIG. 4 is a cross-sectional view showing a conductive particle according to a fourth embodiment of the present invention. FIG. 5: is sectional drawing which shows typically the bonded structure using the electroconductive particle which concerns on the 1st Embodiment of this invention.

  Hereinafter, the present invention will be described in detail.

(Conductive particles)
The conductive particle according to the present invention comprises substrate particles and a conductive part. The conductive portion is disposed on the surface of the base particle. The conductive portion has a plurality of protrusions on the outer surface. In the conductive particle according to the present invention, the percentage of protrusions having an aspect ratio of 2 or more and 4 or less is 20% or more in 100% of the total number of the plurality of protrusions.

  By employing the above-described configuration in the conductive particle according to the present invention, the connection resistance can be lowered when the electrodes are electrically connected using the conductive particle according to the present invention. In particular, when the oxide film is formed on the outer surface of the conductive portion of the conductive particle and the surface of the electrode, the oxide film is easily pierced by the protrusion, and the connection resistance becomes low.

  From the viewpoint of making it easier for the projections to break through the oxide film and further enhancing the connection reliability between the electrodes, the proportion of the projections having an aspect ratio of 2 or more and 4 or less in the total number 100% of the plurality of projections is Preferably it is 25% or more, more preferably 30% or more, still more preferably 50% or more, and most preferably 100%.

  From the viewpoint of making it easier for the projections to break through the oxide film and further enhancing the connection reliability between the electrodes, the proportion of the projections having an aspect ratio of 3 or more and 4 or less is 100% of the total number of the plurality of projections. Preferably, it is 10% or more, more preferably 12% or more, further preferably 20% or more, and most preferably 100%.

  Also, the aspect ratio of the protrusions is defined based on the SEM image of the conductive particles. As L1 and L2 are illustrated in FIG. 1, the protrusion height is defined as the distance from the intersection of the broken line L1 and the broken line L2 to the tip of the protrusion, which is A. Further, the protrusion width is defined as the maximum value of the width of the protrusion in the direction orthogonal to the line connecting the center of the conductive particle and the tip of the protrusion, which is referred to as B. The aspect ratio of the protrusions is defined by A / B.

  The projections having an aspect ratio in the above-mentioned range are electrolessly plated on the surface of the base particle, for example, in the initial reaction step in the formation of the conductive portion, and then the core substance is attached to the surface of the particle. It can form by passing through the middle period reaction process which performs electrolytic plating, and the later reaction process which further performs electroless plating.

  The average height of the plurality of projections is appropriately adjusted to satisfy the above aspect ratio. The average height of the plurality of projections is preferably 50 nm or more, more preferably 100 nm or more, preferably 900 nm or less, more preferably 400 nm or less. The connection resistance between electrodes becomes effectively low that the average height of the said protrusion is more than the said minimum and below the said upper limit.

  The height of the protrusion is a virtual line (broken line shown in FIG. 1) of the conductive portion on the line (broken line L1 shown in FIG. 1) connecting the center of the conductive particle and the tip of the protrusion. L2) The distance from the top (on the outer surface of the spherical conductive particle when assuming no protrusion) to the tip of the protrusion is shown. 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 projection is shown. The average height of the protrusions is an average of the heights of the protrusions in one conductive particle.

  It is preferable that the tips of the plurality of protrusions extend outward from the center of the conductive particles from the viewpoint of making the oxide film more easily pierced by the protrusions and further enhancing the connection reliability between the electrodes.

  From the viewpoint that the projections further break through the oxide film and the connection reliability between the electrodes is further enhanced, the plurality of projections may include projections formed by connecting a plurality of particles in a row. preferable. From the viewpoint of making it easier for the projections to break through the oxide film and to further improve the connection reliability between the electrodes, the projections formed by connecting a plurality of the above-mentioned particles in a row have a bent portion on the outer peripheral surface Is preferred. It is preferable that a projection formed by connecting a plurality of particles in a row has a bent portion on the side surface in the longitudinal direction of the projection.

  Regarding the above projections per conductive particle, from the viewpoint of further lowering the connection resistance, the surface area of the portion with the projections is 30% or more in 100% of the total surface area of the outer surface of the conductive part Is preferably 50% or more.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. In the drawings referred to, the size, thickness and the like are appropriately changed from the actual size and thickness for convenience of illustration. In particular, the size and shape of the projections are described schematically.

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

  The conductive particle 1 shown in FIG. 1 includes base particles 2, a conductive portion 3, and a plurality of core substances 4. The conductive particle 1 is a particle having a base particle 2 and a conductive portion 3 disposed on the surface of the base particle 2. The conductive portion 3 is a conductive layer.

  The conductive portion 3 is disposed on the surface of the base particle 2. The conductive portion 3 covers the surface of the base particle 2. The conductive particle 1 is a coated particle in which the surface of the substrate particle 2 is covered by the conductive portion 3.

  The conductive particle 1 has a plurality of protrusions 1 a on the conductive surface. The conductive portion 3 has a plurality of protrusions 3a on the outer surface. A plurality of core substances 4 are arranged on the surface of the base particle 2. The plurality of core substances 4 are disposed so as not to be in contact with the substrate particles 2. The core substance 4 may be in contact with the base particle 2. A plurality of core substances 4 are embedded in the conductive part 3. The core substance 4 is disposed inside the protrusions 1a and 3a. The conductive layer 3 covers a plurality of core substances 4. The outer surface of the conductive portion 3 is raised by the plurality of core substances 4, and the protrusions 1a and 3a are formed.

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

  The conductive particle 11 shown in FIG. 2 includes base particles 2, a conductive portion 12, and an insulating substance 13. The conductive particle 11 is a particle having a base particle 2 and a conductive portion 12 disposed on the surface of the base particle 2. The conductive portion 12 is a conductive layer. The conductive particles 1 and the conductive particles 11 differ only in the presence or absence of the core substance 4 and the presence or absence of the insulating substance 13.

  The conductive particles 11 do not have a core substance. The conductive portion 12 has a first portion and a second portion which is thicker than the first portion. The conductive particle 11 has a plurality of protrusions 11 a on the conductive surface. The portion excluding the plurality of protrusions 11 a is the first portion of the conductive portion 12. The plurality of protrusions 11 a are located in the second portion where the thickness of the conductive portion 12 is thick. The conductive portion 12 has a plurality of protrusions 12 a on the outer surface. As described above, the conductive particles according to the present invention may use the core material to form the protrusions on the outer surface of the conductive part, but may not use the core material.

  A plurality of insulating substances 13 are disposed on the outer surface of the conductive portion 12. In the present embodiment, the insulating substance 13 is an insulating particle. Thus, the conductive particles may comprise an insulating material disposed on the outer surface of the conductive portion.

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

  The conductive particle 21 shown in FIG. 3 includes a base particle 2, a conductive portion 22, and a plurality of core substances 4.

  The conductive portion 22 has a first conductive portion 22A and a second conductive portion 22B. The first conductive portion 22 </ b> A is disposed on the surface of the base particle 2. The first conductive portion 22A is disposed between the base particle 2 and the second conductive portion 22B. The second conductive portion 22B is disposed on the outer surface of the first conductive portion 22A. The second conductive portion 22B is in contact with the first conductive portion 22A. The conductive particle 21 is a coated particle in which the surface of the substrate particle 2 is covered with the first conductive portion 22A and the second conductive portion 22B.

  The outer shape of the first conductive portion 22A is spherical. The first conductive portion 22A does not have a plurality of protrusions on the outer surface. The conductive particles 21 have a plurality of protrusions 21 a on the conductive surface. The conductive portion 22 has a plurality of protrusions 22 a on the outer surface. The second conductive portion 22B has a plurality of protrusions 22Ba on the outer surface.

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

  The conductive particles 31 shown in FIG. 4 include base particles 2, conductive portions 32, and a plurality of core substances 4.

  The conductive portion 32 has a first conductive portion 32A and a second conductive portion 32B. The first conductive portion 32 </ b> A is disposed on the surface of the base particle 2. The first conductive portion 32A is disposed between the base particle 2 and the second conductive portion 32B. The second conductive portion 32B is disposed on the outer surface of the first conductive portion 32A. The second conductive portion 32B is in contact with the first conductive portion 32A. The conductive particle 31 is a coated particle in which the surface of the substrate particle 2 is covered with the first conductive portion 32A and the second conductive portion 32B.

  The conductive particles 31 have a plurality of protrusions 31 a on the conductive surface. The conductive portion 32 has a plurality of protrusions 32 a on the outer surface. The first conductive portion 32A has a plurality of protrusions 32Aa on the outer surface. The conductive portion 32B has a plurality of protrusions 32Ba on the outer surface.

  Hereinafter, other details of the conductive particles will be described. In the following description, "(meth) acrylic" means one or both of "acrylic" and "methacrylic", and "(meth) acrylate" means one or both of "acrylate" and "methacrylate". means.

[Base particle]
Examples of the substrate particles include resin particles, inorganic particles other than metal particles, organic-inorganic hybrid particles, metal particles and the like. 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 may be core-shell particles.

  The base material particles are more preferably resin particles or organic-inorganic hybrid particles, and may be resin particles or organic-inorganic hybrid particles. The use of these preferred substrate particles results in more suitable conductive particles due to the electrical connection between the electrodes.

  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 pressure-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 becomes large. Therefore, the connection resistance between the electrodes is further lowered.

  Various organic substances are suitably used as the resin for forming the above-mentioned 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, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polysulfone, polyphenylene Oxide, polyacetal, polyimide, polyamide imide, 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. A resin for forming the above-mentioned resin particles can be designed because resin particles having arbitrary compression physical properties suitable for the conductive material can be designed and synthesized, and the hardness of the substrate particles can be easily controlled to a suitable range. The polymer is preferably a polymer obtained by polymerizing one or two or more polymerizable monomers having a plurality of ethylenic unsaturated groups.

  When the resin particles are obtained by polymerizing a monomer having an ethylenically unsaturated group, as the monomer having an ethylenically unsaturated group, a monomer having a crosslinking property with a non-crosslinkable monomer is used. And a mer.

  Examples of the non-crosslinkable monomers include styrene-based monomers such as styrene and α-methylstyrene; carboxyl-containing monomers such as (meth) acrylic acid, maleic acid and maleic anhydride; methyl ( Meta) 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 meta) 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 and propyl vinyl ether; vinyl acids such as vinyl acetate, vinyl butyrate, vinyl laurate and vinyl stearate Esters; unsaturated hydrocarbons such as ethylene, propylene, isoprene and butadiene; trifluoromethyl (meth) acrylates, pentafluoroethyl (meth) acrylates, halogen-containing monomers such as vinyl chloride, vinyl fluoride and chlorostyrene, etc. Can be mentioned.

  Examples of the crosslinkable monomer include, for example, tetramethylolmethane tetra (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and dipentamer. 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) Multifunctional (meth) acrylates such as acrylate, (poly) tetramethylene di (meth) acrylate, 1,4-butanediol di (meth) acrylate; triallyl (iso) cyanurate, thoria Rutorimeriteto, divinylbenzene, diallyl phthalate, diallyl acrylamide, diallyl ether, .gamma. (meth) acryloxy propyl trimethoxy silane, trimethoxy silyl styrene, include silane-containing monomers such as vinyltrimethoxysilane.

  The said resin particle can be obtained by polymerizing the polymerizable monomer which has the said ethylenically unsaturated group by a well-known method. Examples of this method include a method of suspension polymerization in the presence of a radical polymerization initiator, and a method of swelling and polymerizing a monomer with a radical polymerization initiator using non-crosslinked seed particles.

  When the substrate particles are inorganic particles or organic-inorganic hybrid particles other than metal particles, examples of the inorganic substance for forming the substrate particles include silica, alumina, barium titanate, zirconia, carbon black and the like. . The inorganic substance for forming the organic-inorganic hybrid particles is preferably not a metal. The particles formed of the above 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, baking is carried out as necessary. The particles obtained by carrying out are mentioned. As said organic-inorganic hybrid particle | grains, the organic-inorganic hybrid particle | grains etc. which were formed, for example by bridge | crosslinking alkoxy silyl polymer and acrylic resin are mentioned.

  The organic-inorganic hybrid particle is preferably a core-shell type organic-inorganic hybrid particle having a core and a shell disposed on the surface of the core. It is preferable that the said core is an organic core. It is preferable that the said shell is an inorganic shell. From the viewpoint of effectively reducing the connection resistance between the electrodes, the base particle is preferably an organic-inorganic hybrid particle having an organic core and an inorganic shell disposed on the surface of the organic core.

  As a material for forming the said organic core, resin etc. for forming the resin particle mentioned above are mentioned.

  As a material for forming the said inorganic shell, the inorganic substance for forming the base material particle mentioned above is mentioned. 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 by a sol-gel method and then sintering the shell. The metal alkoxide is preferably a silane alkoxide. The inorganic shell is preferably formed of a silane alkoxide.

  When the base particle is a metal particle, examples of the metal for forming the metal particle include silver, copper, nickel, silicon, gold and titanium. However, it is preferable that the said base material particle is not a metal particle.

  The particle diameter of the substrate particle is preferably 0.1 μm or more, more preferably 0.5 μm or more, still more preferably 2 μm or more, preferably 5 μm or less, more preferably 3 μm or less. When the particle diameter of the base particle is not less than the lower limit and not more than the upper limit, the distance between the electrodes is reduced, and small conductive particles can be obtained even if the thickness of the conductive portion is increased.

  The particle diameter of the substrate particle indicates a diameter when the substrate particle is spherical, and indicates a maximum diameter when the substrate particle is not spherical.

  In the plurality of conductive particles, the particle diameter of the base particle can be determined as an average particle diameter. The average particle size indicates a number average particle size. For example, conductive particles are added to “Technobit 4000” manufactured by Kulzer Co. so that the content is 30% by weight, and dispersed to prepare a conductive particle inspection embedded resin. The cross section of the conductive particles is cut out using an ion milling apparatus ("IM 4000" manufactured by Hitachi High-Technologies Corporation) so as to pass near the center of the conductive particles dispersed in the embedded resin for inspection. Then, using a field emission scanning electron microscope (FE-SEM), the image magnification is set to 25000 times, 50 conductive particles are randomly selected, and base particles of each conductive particle are selected. Observe. The particle diameter of the base material particles in the obtained conductive particles is measured, and the average of the particle diameters of the base material particles is determined by arithmetic averaging.

[Conductive part]
The metal for forming the said electroconductive part is not specifically limited. Examples of the metal include gold, silver, palladium, rhodium, ruthenium, copper, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, thallium, germanium, cadmium , Silicon, tungsten, molybdenum and their alloys. Among them, an alloy containing tin, nickel, palladium, copper or gold is preferable because the connection resistance between the electrodes can be further lowered, and nickel or palladium is preferable. The material of the conductive portion is preferably nickel or a nickel alloy.

  The conductive portion may include a first conductive portion and a second conductive portion disposed on the outer surface of the first conductive portion.

  From the viewpoint of further lowering the connection resistance between the electrodes, the conductive portion is preferably a conductive portion containing nickel or a conductive portion (region) containing nickel. From the viewpoint of further reducing the connection resistance between the electrodes, at least one of the first conductive portion and the second conductive portion is preferably a conductive portion containing nickel, and the first conductive portion and More preferably, at least one of the second conductive portions is a conductive portion containing nickel and having a crystal structure.

  From the viewpoint of further lowering the connection resistance between the electrodes, in the conductive portion containing nickel and having a crystal structure, the ratio of (111) plane in X-ray diffraction is preferably 60% or more, more preferably 80% or more, More preferably, it is 90% or more. By satisfying such a ratio of (111) planes, the projections are less likely to be broken and the conductive portion is less likely to be broken. As a result, the connection resistance between the electrodes is further reduced.

  The conductive portion containing nickel includes not only the case where only nickel is used as a metal, but also the case where nickel and other metals are used. The conductive portion containing nickel may be a nickel alloy portion.

  The conductive part containing nickel preferably contains nickel as a main metal. The content (average content) of nickel is preferably 50% by weight or more in 100% by weight of the conductive part containing nickel. The content of nickel is preferably 65% by weight or more, more preferably 80% by weight or more, and still more preferably 90% by weight or more in 100% by weight of the conductive part containing nickel. The connection resistance between electrodes becomes still lower that content of content of nickel is more than the above-mentioned lower limit.

  From the viewpoint of further lowering the connection resistance between the electrodes, the conductive portion containing nickel preferably contains phosphorus or boron, and more preferably contains phosphorus. The conductive part containing nickel may contain boron. The content (average content) of phosphorus and the content (average content) of boron are preferably more than 0% by weight, more preferably 0.1% by weight or more, in 100% by weight of the conductive part containing nickel. It is preferably 2% by weight or more, preferably 20% by weight or less, and more preferably 15% by weight or less. When the phosphorus content and the boron content are equal to or higher than the lower limit and lower than the upper limit, connection resistance is further lowered.

  In order to further lower the connection resistance between the electrodes and further improve the connection reliability between the electrodes under high temperature and high humidity, the content of phosphorus is 5% by weight in 100% by weight of the conductive part containing nickel. It is more preferable that it be less than. From the viewpoint of effectively expressing both the low connection resistance between the electrodes and the high connection reliability between the electrodes under high temperature and high humidity, the content of phosphorus is 100% by weight of the conductive part containing nickel. Preferably, it is more than 0% by weight, more preferably 0.1% by weight or more, still more preferably 2% by weight or more. When the content of phosphorus is equal to or more than the above lower limit, the connection resistance is further lowered. From the viewpoint of further lowering the connection resistance, the content of phosphorus is preferably 4.9% by weight or less, more preferably 4% by weight or less, still more preferably 3% by weight, in 100% by weight of the conductive portion containing nickel. It is below.

  As a method of controlling the content of nickel, boron and phosphorus in the conductive portion, for example, a method of controlling the pH of a nickel plating solution when forming the conductive portion by electroless nickel plating, conductivity by electroless nickel plating Method of adjusting the concentration of the boron-containing reducing agent when forming the portion, a method of adjusting the concentration of the phosphorus-containing reducing agent when forming the conductive portion by electroless nickel plating, and the nickel concentration in the nickel plating solution And the like.

  The conductive portion containing nickel preferably contains tungsten or molybdenum. The use of tungsten or molybdenum makes the connection resistance between the electrodes even lower. The content of tungsten and the content of molybdenum are preferably 1% by weight or more, more preferably 5% by weight or more, preferably 20% by weight or less, more preferably 10% by weight in 100% by weight of the conductive part containing nickel. % Or less. When the content of tungsten and the content of molybdenum are at least the lower limit and the upper limit, the connection resistance between the electrodes is effectively reduced.

  In the method of forming a conductive portion containing nickel by electroless plating, a catalyzing step and an electroless plating step are generally performed. Hereinafter, an example of a method of forming an alloy plating layer containing nickel, phosphorus and tungsten on the surface of the resin particle by electroless plating will be described.

  In the catalyzing step, a catalyst serving as a starting point for forming a plating layer by electroless plating is formed on the surface of the resin particle.

  As a method of forming the catalyst on the surface of the resin particle, for example, after adding the resin particle to a solution containing palladium chloride and tin chloride, the surface of the resin particle is activated with an acid solution or an alkaline solution, A method of depositing palladium on the surface of a resin particle, and after adding the resin particle to a solution containing palladium sulfate and aminopyridine, the surface of the resin particle is activated with a solution containing a reducing agent to obtain resin particles The method etc. which precipitate palladium on the surface are mentioned. A phosphorus-containing reducing agent is used as the reducing agent. In addition, by using a phosphorus-containing reducing agent as the reducing agent, a conductive layer containing phosphorus can be formed. In the case of forming a conductive layer containing boron, a boron-containing reducing agent may be used as the reducing agent.

  In the electroless plating step, a nickel plating bath containing a nickel-containing compound, a phosphorus-containing reducing agent or a boron-containing reducing agent, a tungsten-containing compound, a complexing agent, and a stabilizer is suitably used.

  By immersing the resin particles in a nickel plating bath, nickel can be deposited on the surface of the resin particles having the catalyst formed on the surface, and a conductive layer containing nickel, phosphorus and tungsten can be formed.

  Examples of the nickel-containing compound include nickel sulfate and nickel chloride. The nickel-containing compound is preferably a nickel salt.

  Examples of the phosphorus-containing reducing agent include sodium hypophosphite and the like. In addition to the phosphorus-containing reducing agent, a boron-containing reducing agent may be used. Examples of the boron-containing reducing agent include dimethylamine borane, sodium borohydride and potassium borohydride.

  Examples of the tungsten-containing compounds include tungsten boride and sodium tungstate.

  Preferred examples of the complexing agent include: monocarboxylic acid type complexing agents such as sodium acetate and sodium propionate; dicarboxylic acid type complexing agents such as disodium malonate; tricarboxylic acid type complexing such as disodium succinate Agents; hydroxy acid type complexing agents such as lactic acid, DL-malic acid, Rochelle salt, sodium citrate and sodium gluconate; amino acid type complexing agents such as glycine and EDTA; amine type complexing agents such as ethylene diamine; Etc., and the like. Only one type of the complexing agent may be used, or two or more types may be used in combination.

  As said stabilizer, a lead compound, a bismuth compound, and a thallium compound etc. are mentioned. Specific examples of these stabilizers include sulfates, carbonates, acetates, nitrates and hydrochlorides of metals (lead, bismuth, thallium) constituting the compound. In consideration of environmental impact, bismuth compounds or thallium compounds are preferred.

  The method of forming the conductive part on the surface of the particle is not particularly limited. As a method of forming the conductive portion, for example, a method by electroless plating, a method by electroplating, a method by physical vapor deposition, and a method of coating metal powder or a paste containing metal powder and a binder on the surface of particles It can be mentioned. Among them, the method by electroless plating is preferable because the formation of the conductive portion is simple. Examples of the method by physical vapor deposition include methods such as vacuum deposition, ion plating and ion sputtering.

  The thickness of the portion without the projections of the conductive portion is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 1 μm or less, more preferably 0.3 μm or less. Sufficient conductivity can be obtained when the thickness of the portion without the projection of the conductive portion is not less than the lower limit and not more than the upper limit, and the conductive particles do not become too hard, so that the conductive particles are conductive when connected Particles are deformed sufficiently.

  In the plurality of conductive particles, the thickness of the portion of the conductive portion without the protrusion can be obtained as an average of the thickness of the portion without the protrusion of the conductive portion in the plurality of conductive particles. With a plurality of conductive particles, the thickness of the portion of the conductive portion without projections can be measured as follows. For example, conductive particles are added to “Technobit 4000” manufactured by Kulzer Co. so that the content is 30% by weight, and dispersed to prepare a conductive particle inspection embedded resin. The cross section of the conductive particles is cut out using an ion milling apparatus ("IM 4000" manufactured by Hitachi High-Technologies Corporation) so as to pass near the center of the conductive particles dispersed in the embedded resin for inspection. Then, using a field emission scanning electron microscope (FE-SEM), the image magnification is set to 50,000 times, 20 conductive particles are randomly selected, and the conductive portion of each conductive particle is observed. Do. The thickness of the conductive portion in the obtained conductive particles is measured, and the thickness is arithmetically averaged to obtain the thickness of the conductive portion.

  In the case where the conductive portion is formed of a plurality of layers, the thickness of the portion without the projections of the outermost conductive layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, and preferably 0. 0.5 μm or less, more preferably 0.1 μm or less. If the thickness of the portion without the projections of the outermost conductive layer is not less than the lower limit and not more than the upper limit, the coating by the outermost conductive layer becomes uniform, the corrosion resistance becomes sufficiently high, and between the electrodes Connection resistance is sufficiently low. Further, the thinner the thickness of the gold layer when the outermost layer is a gold layer, the lower the cost.

  The thickness of the portion without the projection of the conductive portion can be measured, for example, by observing the cross section of the conductive particle using a transmission electron microscope (TEM).

[Core substance]
The conductive particles preferably include a plurality of core substances that raise the surface of the conductive portion so as to form a plurality of the protrusions in the conductive portion. The core substance is preferably disposed inside the plurality of protrusions. By embedding the core substance in the conductive portion, it is easy for the conductive portion to have a plurality of protrusions on the outer surface. However, in order to form protrusions on the surfaces of the conductive particles and the conductive portion, it is not necessary to necessarily use the core substance, and it is preferable not to use the core substance.

  As a method of forming the above-mentioned projection, after making a core substance adhere to the surface of substrate particles, a method of forming a conductive part by electroless plating, and after forming a conductive part by electroless plating on the surface of substrate particles Examples include a method of depositing a core substance and forming a conductive part by electroless plating, and a method of adding a core substance at a stage of forming a conductive part by electroless plating on the surface of a substrate particle.

  For example, as a method of forming the above projections without using a core substance, a method of forming a projection by depositing a metal core with a reducing agent and adsorbing a metal complex in electroless plating with a reducing agent, electroless plating Method of forming projections by forming metal hydroxides in a strong alkali solution and adsorbing particles to metal complexes in the metal complex, depositing a metal nucleus by adding a palladium complex as a catalyst during electroless plating, particles And a method of forming protrusions by adding a plating deposition inhibitor during electroless plating, and controlling the growth rate of plating deposition. Among them, a method of forming a protrusion by depositing a metal core with a reducing agent and adsorbing the metal complex in electroless plating with a reducing agent is preferable because the size of the protrusion core can be easily controlled.

  In the step of depositing metal nuclei with a reducing agent and adsorbing metal complexes in electroless plating using a reducing agent, the addition of the reducing agent solution and the dropping of the electroless plating solution are a series of steps, usually several times, preferably once. The method of forming a projection nucleus by performing the above, more preferably three times or more, further preferably five times or more is preferable.

  Examples of the reducing agent include sodium hypophosphite, hydrazine, formalin, formic acid, dimethylamine borane, sodium borohydride and potassium borohydride.

  As a method of arranging the core substance on the surface of the above-mentioned base material particle, for example, the core substance is added to the dispersion liquid of the base material particle, and the core substance is added to the surface of the base material particle. And the core material is added to the container containing the substrate particles, and the core material is attached to the surface of the substrate particles by mechanical action such as rotation of the container. . Among them, a method in which the core substance is accumulated on the surface of the base material particles in the dispersion liquid and adhered is preferable because the amount of the core substance to be attached can be easily controlled.

  Examples of the material of the core substance include conductive substances and non-conductive substances. Examples of the conductive substance include metals, metal oxides, conductive nonmetals such as graphite, and conductive polymers. Examples of the conductive polymer include polyacetylene and the like. Examples of the nonconductive material include silica, alumina, barium titanate and zirconia. Among them, metals are preferable because the conductivity can be enhanced and the connection resistance can be effectively lowered. The core material is preferably metal particles. As a metal which is a material of the said core substance, the metal quoted as a material of the said conductive material can be used suitably.

  Specific examples of the material of the core material include nickel (Vickers hardness 50 to 400 HV), silica (silicon dioxide, Vickers hardness 850 to 1000 HV), titanium oxide (Vickers hardness 1200 to 1600 HV), zirconia (Vickers hardness 1700 to 2200) And alumina (Vickers hardness 2100-3800 HV), tungsten carbide (Vickers hardness 1700-4000 HV), diamond (Vickers hardness 5000-9000 HV), and the like. The material of the core material is preferably nickel, silica, titanium oxide, zirconia, alumina, tungsten carbide or diamond, more preferably silica, titanium oxide, zirconia, alumina, tungsten carbide or diamond, titanium oxide More preferably, they are zirconia, alumina, tungsten carbide or diamond, particularly preferably zirconia, alumina, tungsten carbide or diamond. The Vickers hardness of the material of the core material is preferably 50 or more, more preferably 100 or more, still more preferably 500 or more, and particularly preferably 700 or more.

  Specific examples of the material of the core material include barium titanate (Mohs hardness 4.5), nickel (Mohs hardness 5), silica (silicon dioxide, Mohs hardness 6 to 7), titanium oxide (Mohs hardness 7), zirconia (Mohrs hardness 8 to 9), alumina (Mohrs hardness 9), tungsten carbide (Mohrs hardness 9), diamond (Mohrs hardness 10) and the like. The material of the core material is preferably nickel, silica, titanium oxide, zirconia, alumina, tungsten carbide or diamond, more preferably silica, titanium oxide, zirconia, alumina, tungsten carbide or diamond, titanium oxide More preferably, they are zirconia, alumina, tungsten carbide or diamond, particularly preferably zirconia, alumina, tungsten carbide or diamond. The Mohs hardness of the material of the core material is preferably 5 or more, more preferably 6 or more, still more preferably 7 or more, and particularly preferably 7.5 or more.

  It is preferable that the core substance does not contain a metal, or that the main metal contained in the core substance is different from the main metal contained in the conductive portion in contact with the core substance. It is preferable that the said core substance contains a metal, and it is preferable that the main metal contained in the said core substance and the main metal contained in the said electroconductive part differ. The metals include metals in metal oxides and metals in metal alloys. The Mohs hardness of the material contained in the core material is preferably higher than the Mohs hardness of the main metal such as the metal or alloy contained in the conductive part. The Vickers hardness of the main metal such as metal or alloy contained in the core material is preferably higher than the Vickers hardness of the main metal such as metal or alloy contained in the conductive portion.

  The shape of the core material is not particularly limited. The shape of the core substance is preferably massive. Examples of the core substance include particulate lumps, agglomerates in which a plurality of microparticles are agglomerated, and amorphous lumps.

  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. The connection resistance between electrodes becomes effectively low that the average diameter of the said core substance is more than the said minimum and below the said upper limit.

  The “average diameter (average particle diameter)” of the core substance indicates a number average diameter (number average particle diameter). Arbitrary 20 core materials, preferably 50 are observed with an electron microscope or an optical microscope, and it calculates | requires by calculating an average value. In the case of measuring the average diameter of the core substance in the conductive particles, for example, the average diameter of the core substance can be measured as follows. For example, conductive particles are added to “Technobit 4000” manufactured by Kulzer Co. so that the content is 30% by weight, and dispersed to prepare a conductive particle inspection embedded resin. The cross section of the conductive particles is cut out using an ion milling apparatus ("IM 4000" manufactured by Hitachi High-Technologies Corporation) so as to pass near the center of the dispersed conductive particles in the embedded resin for inspection. Then, using a field emission scanning electron microscope (FE-SEM), the image magnification is set to 50,000 times, 20 conductive particles are randomly selected, and the protrusions of the respective conductive particles are observed. . The diameter of the core substance in the obtained conductive particles is measured, and it is arithmetically averaged to obtain the average diameter of the core substance.

[Insulating substance]
The conductive particles according to the present invention preferably include an insulating material disposed on the outer surface of the conductive portion. In this case, when conductive particles are used for connection between 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 adjacent electrodes in the lateral direction rather than between the upper and lower electrodes. In addition, at the time of connection between the electrodes, by pressurizing the conductive particles with two electrodes, the insulating substance between the conductive portion of the conductive particles and the electrodes can be easily removed. Since the conductive portion has a plurality of protrusions on the outer surface, the insulating material between the conductive portion of the conductive particle and the electrode can be easily removed.

  The insulating material is preferably insulating particles, because the insulating material can be more easily removed at the time of pressure bonding between the electrodes.

  Specific examples of the insulating resin which is the material of the insulating material include polyolefins, (meth) acrylate polymers, (meth) acrylate copolymers, block polymers, thermoplastic resins, crosslinked resins of thermoplastic resins, thermal Examples thereof include curable resins and water-soluble resins.

  Examples of the above-mentioned polyolefins include polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer and the like. 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. An epoxy resin, a phenol resin, a melamine resin etc. are mentioned as said thermosetting resin. Examples of the water-soluble resin include polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinyl pyrrolidone, polyethylene oxide and methyl cellulose. Among them, water-soluble resins are preferable, and polyvinyl alcohol is more preferable.

  As a method of arranging an insulating material on the surface of the above-mentioned conductive part, a chemical method, a physical or mechanical method, etc. are mentioned. 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 deposition, spraying, dipping and vacuum deposition. Among them, a method in which the insulating material is disposed on the surface of the conductive portion via a chemical bond is preferable because the insulating material is difficult to be released.

  The outer surface of the conductive part and the surface of the insulating particle may be coated with a compound having a reactive functional group. The outer surface of the conductive part and the surface of the insulating particle 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 to the outer surface of the conductive part, the carboxyl group may be chemically bonded to a functional group on the surface of the insulating particle through a polymer electrolyte such as polyethylene imine.

  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 substance 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 conductive particles are dispersed in the binder resin as the average diameter of the insulating substance is equal to or more than the above lower limit, the conductive portions in the plurality of conductive particles are less likely to be in contact with each other. When the average diameter of the insulating particles is equal to or less than the above upper limit, it is not necessary to excessively increase the pressure in order to eliminate the insulating material between the electrodes and the conductive particles when connecting the electrodes, There is no need to heat it.

  The “average diameter (average particle diameter)” of the above-mentioned insulating substance indicates the number average diameter (number average particle diameter). The average diameter of the insulating material can be determined using a particle size distribution measuring device or the like.

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

  The binder resin is not particularly limited. A well-known insulating resin is used as said binder resin.

  The binder resin preferably contains a thermoplastic component (thermoplastic compound) or a curable component, and more preferably contains a curable component. As said curable component, a photocurable component and a thermosetting component are mentioned. It is preferable that the said photocurable component contains a photocurable compound and a photoinitiator. It is preferable that the said thermosetting component contains a thermosetting compound and a thermosetting agent. As said binder resin, a vinyl resin, a thermoplastic resin, curable resin, a thermoplastic block copolymer, an elastomer, etc. are mentioned, for example. The binder resin may be used alone or in combination of two or more.

  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. As said curable resin, an epoxy resin, a urethane resin, a polyimide resin, unsaturated polyester resin etc. are mentioned, for example. The curable resin may be a room temperature curable resin, a thermosetting resin, a photocurable resin, or a moisture curable resin. The curable resin may be used in combination with a curing agent. Examples of the thermoplastic block copolymer include styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, hydrogenated substance of styrene-butadiene-styrene block copolymer, and styrene-isoprene. -The hydrogenated substance of a styrene block copolymer, etc. are mentioned. 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 is, for example, a filler, an extender, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, and light stability. Various additives such as agents, UV absorbers, lubricants, antistatic agents and flame retardants may be included.

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

  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, in 100% by weight of the conductive material. It is 99.99 wt% or less, more preferably 99.9 wt% or less. When the content of the binder resin is not less than the lower limit and not more than the upper limit, conductive particles are efficiently disposed between the electrodes, and the connection reliability of the connection target member connected by the conductive material is further enhanced.

  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 in 100% by weight of the conductive material. The content is more preferably 40% by weight or less, particularly preferably 20% by weight or less, and most preferably 10% by weight or less. When the content of the conductive particles is not less than the lower limit and not more than the upper limit, conduction reliability between the electrodes is further enhanced.

(Connected structure)
A connection structure can be obtained by connecting members to be connected using the conductive particles or 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 material of the connection portion is the above-described. It is preferable that it is the electroconductive material which is the electroconductive particle which contains these, or the electroconductive particle and binder resin which were mentioned above. It is preferable that the connection portion is a connection structure formed of the above-described conductive particles, or formed of a conductive material including the above-described conductive particles and a binder resin. When the conductive particles are used, the connection portion itself is the conductive particles. That is, the first and second connection target members are connected by the conductive particles.

  FIG. 5: is sectional drawing which shows typically the bonded structure using the electroconductive particle which concerns on the 1st Embodiment of this invention.

  The connection structure 51 shown in FIG. 5 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 particle 1. Connecting portion 54 includes conductive particles 1 and binder resin 54 a. In FIG. 5, the conductive particles 1 are schematically illustrated for the convenience of illustration. Instead of the conductive particles 1, conductive particles 11, 21, 31 or the like may be used.

  The first connection target member 52 has a plurality of first electrodes 52 a on the surface (upper surface). The second connection target member 53 has a plurality of second electrodes 53a on the front surface (lower surface). The first electrode 52 a and the second electrode 53 a are electrically connected by one or more 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 said connection structure is not specifically 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, and after obtaining the laminate, the laminate is heated and pressed. Methods etc. The pressure of the said pressurization is about 9.8 * 10 < ⁴ > -4.9 * 10 < ⁶ > Pa. The temperature of the heating is about 120 to 220 ° C. The pressure of the said pressurization for connecting the electrode of a flexible printed circuit board, the electrode arrange | positioned on a resin film, and the electrode of a touch panel is about 9.8 * 10 < ⁴ > -1.0 * 10 < ⁶ > Pa.

  Specific examples of the connection target member include electronic components such as a semiconductor chip, a capacitor, and a diode, and electronic components such as a printed circuit board, a flexible printed circuit, a circuit board such as a glass epoxy substrate and a glass substrate, and the like. The connection target member is preferably an electronic component. It is preferable that the said electroconductive particle is used for the electrical connection of the electrode in an electronic component.

  As an electrode provided in the said connection object member, 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, a tungsten electrode, etc. are mentioned. When the connection target 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 a metal oxide layer may be sufficient. As a material of the said metal oxide layer, the indium oxide in which the trivalent metal element was doped, the zinc oxide in which the trivalent metal element was doped, etc. are mentioned. Sn, Al, Ga, etc. are mentioned as said trivalent metal element.

  Hereinafter, the present invention will be specifically described by way of examples and comparative examples. The invention is not limited to the following examples.

Example 1
(1) Preparation of conductive particles Reaction pretreatment:
As the base particle A, a divinylbenzene copolymer resin particle ("Micropearl SP-203" manufactured by Sekisui Chemical Co., Ltd.) having a particle diameter of 3.0 μm was prepared.

  After dispersing 10 parts by weight of the above resin particles in 100 parts by weight of an alkaline solution containing 5% by weight of a palladium catalyst solution using an ultrasonic disperser, the solution was filtered to take out the resin particles. Next, the resin particles were added to 100 parts by weight of a 1% by weight solution of dimethylamine borane to activate the surface of the resin particles. After 40 parts by weight of the surface-activated resin particles were sufficiently washed with water, they were added to 200 parts by weight of distilled water and dispersed to obtain a dispersion. This dispersion was placed in 1 L of a solution containing 0.09 mol / L of nickel sulfate and 30 ppm of thallium nitrate to obtain a particle mixture.

Early reaction:
0.49 mol / L nickel sulfate, 0.067 mol / L dimethylamine borane, 0.025 mol / L citric acid, 0.16 mol / L malonic acid, 0.22 mol / L succinic acid, 25 ppm thallium nitrate, and 15 ppm bismuth nitrate 1 L of nickel plating solution (pH 7.2) containing was prepared. The pH was adjusted with aqueous ammonia.

  While stirring the obtained particle mixed solution at 40 ° C., the above-mentioned nickel plating solution was dropped at 60 mL / min, electroless nickel plating was performed, and the particle mixed solution after the initial reaction was obtained.

Protrusive nucleation process:
50 mL of a reducing agent solution for protrusion formation of 0.26 mol / L of sodium borohydride aqueous solution was prepared. Separately, 1.17 mol / L nickel sulfate, 0.89 mol / L dimethylamine borane, 0.35 mol / L citric acid, 0.03 mol / L sodium tungstate, 0.22 mol / L succinic acid, 140 ppm thallium nitrate, and nitric acid 150 mL of a nickel plating solution (pH 7.2) containing 30 ppm of bismuth was prepared. The pH was adjusted with sodium hydroxide.

  The particle mixture after the previous reaction is brought to 40 ° C., and a reducing agent solution for protrusion formation (sodium borohydride aqueous solution) is added to this particle mixture at 10 mL / time, and the above nickel plating solution is dropped at 60 mL / min for 30 seconds. And electroless nickel plating was performed. A series of processes of the addition of the sodium borohydride aqueous solution and the dropping of the nickel plating solution were repeated five times to obtain a particle mixed solution after the protrusion nucleus forming process.

Late process:
A 2 L nickel plating solution (pH 9.0) containing 0.47 mol / L of dimethylamine borane was prepared. The pH was adjusted with aqueous ammonia.

  The above-mentioned nickel plating solution was dripped at 40 mL / min to the particle mixed solution after a projection nucleus formation process, and electroless nickel plating was performed. Thus, conductive particles were obtained.

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

(3) Preparation of Connection Structure A transparent glass substrate having an IZO electrode pattern (first electrode, metal Vickers hardness 100 Hv of the electrode surface) of L / S of 10 μm / 20 μm was prepared on the top surface. In addition, a semiconductor chip having an Au electrode pattern (a second electrode, a Vickers hardness of 50 Hv of a metal on the electrode surface) of L / S of 10 μm / 20 μm was prepared on the lower surface.

  The obtained anisotropic conductive paste was coated on the transparent glass substrate to a thickness of 30 μm to form an anisotropic conductive paste layer. Next, the said semiconductor chip was laminated | stacked so that electrodes might oppose on the anisotropic conductive paste layer. Thereafter, while adjusting the temperature of the head so that the temperature of the anisotropic conductive paste layer is 185 ° C., the pressure heating head is placed on the upper surface of the semiconductor chip, and a pressure of 1 MPa is applied to the anisotropic conductive paste layer. It was completely cured at 185 ° C. to obtain a connection structure.

(Example 2)
Protrusive nucleation process:
30 mL of a reducing agent solution for protrusion formation of 0.26 mol / L of sodium borohydride aqueous solution was prepared. Separately, 1.17 mol / L nickel sulfate, 0.89 mol / L dimethylamine borane, 0.35 mol / L citric acid, 0.03 mol / L sodium tungstate, 0.22 mol / L succinic acid, 140 ppm thallium nitrate, and nitric acid 90 mL of a nickel plating solution (pH 7.2) containing 30 ppm of bismuth was prepared. The pH was adjusted with sodium hydroxide.

  In the protrusion nucleus forming step, the number of repetitions of the series of the addition of the protrusion forming reducing agent solution (sodium borohydride aqueous solution) and the dropping of the nickel plating solution is changed from 5 times to 3 times. In the same manner as in 1, a conductive particle, an anisotropic conductive paste and a connection structure were obtained.

(Example 3)
Protrusive nucleation process:
100 mL of a reducing agent solution for protrusion formation of 0.26 mol / L of sodium borohydride aqueous solution was prepared. Separately, 1.17 mol / L nickel sulfate, 0.89 mol / L dimethylamine borane, 0.35 mol / L citric acid, 0.03 mol / L sodium tungstate, 0.22 mol / L succinic acid, 140 ppm thallium nitrate, and nitric acid 300 mL of a nickel plating solution (pH 7.2) containing 30 ppm of bismuth was prepared. The pH was adjusted with sodium hydroxide.

  In the protrusion nucleus forming step, the number of repetitions of the series of the addition of the protrusion forming reducing agent solution (sodium borohydride aqueous solution) and the dropping of the nickel plating solution is changed from 5 times to 10 times. In the same manner as in 1, a conductive particle, an anisotropic conductive paste and a connection structure were obtained.

(Example 4)
Protrusive nucleation process:
150 mL of a reducing agent solution for protrusion formation of 0.26 mol / L of sodium borohydride aqueous solution was prepared. Separately, 1.17 mol / L nickel sulfate, 0.89 mol / L dimethylamine borane, 0.35 mol / L citric acid, 0.03 mol / L sodium tungstate, 0.22 mol / L succinic acid, 140 ppm thallium nitrate, and nitric acid 450 mL of a nickel plating solution (pH 7.2) containing 30 ppm of bismuth was prepared. The pH was adjusted with sodium hydroxide.

  In the protrusion nucleus forming step, the example is repeated except that the number of repetition of a series of steps of addition of a reducing agent solution for protrusion formation (sodium borohydride aqueous solution) and dropping of a nickel plating solution is changed from 5 times to 15 times. In the same manner as in 1, a conductive particle, an anisotropic conductive paste and a connection structure were obtained.

(Example 5)
Protrusive nucleation process:
100 mL of a reducing agent solution for protrusion formation of 0.26 mol / L of sodium borohydride aqueous solution was prepared. Separately, 1.17 mol / L nickel sulfate, 0.89 mol / L dimethylamine borane, 0.35 mol / L citric acid, 0.03 mol / L sodium tungstate, 0.22 mol / L succinic acid, 140 ppm thallium nitrate, and nitric acid 300 mL of a nickel plating solution (pH 7.2) containing 30 ppm of bismuth was prepared. The pH was adjusted with sodium hydroxide.

  In the protrusion nucleus forming step, the number of repetitions of the series of the addition of the protrusion forming reducing agent solution (sodium borohydride aqueous solution) and the dropping of the nickel plating solution is changed from 5 times to 10 times, and the protrusion nucleus forming step Conductive particles, anisotropic conductive paste, and a connection structure are obtained in the same manner as in Example 1 except that the citric acid concentration of the nickel plating solution used in the above is changed from 0.35 mol / L to 0.70 mol / L. The

(Example 6)
Reaction pretreatment:
As the base particle A, a divinylbenzene copolymer resin particle ("Micropearl SP-203" manufactured by Sekisui Chemical Co., Ltd.) having a particle diameter of 3.0 μm was prepared.

  After dispersing 10 parts by weight of the above resin particles in 100 parts by weight of an alkaline solution containing 5% by weight of a palladium catalyst solution using an ultrasonic disperser, the solution was filtered to take out the resin particles. Next, the resin particles were added to 100 parts by weight of a 1% by weight solution of dimethylamine borane to activate the surface of the resin particles. After 40 parts by weight of the surface-activated resin particles were sufficiently washed with water, they were added to 200 parts by weight of distilled water and dispersed to obtain a dispersion.

  Next, 1 g of titanium oxide particle slurry (average particle diameter 150 nm) was added to the dispersion over 3 minutes to obtain a suspension containing the substrate particles A to which the core substance was attached. This suspension was placed in 1 L of a solution containing 0.09 mol / L of nickel sulfate and 30 ppm of thallium nitrate to obtain a particle mixture.

Conductive particles, anisotropic conductive paste and connection structure were obtained in the same manner as in Example 1 except that the reaction pretreatment step was changed as described above (Example 7).
Reaction pretreatment:
As the base particle A, a divinylbenzene copolymer resin particle ("Micropearl SP-203" manufactured by Sekisui Chemical Co., Ltd.) having a particle diameter of 3.0 μm was prepared.

  After dispersing 10 parts by weight of the above resin particles in 100 parts by weight of an alkaline solution containing 5% by weight of a palladium catalyst solution using an ultrasonic disperser, the solution was filtered to take out the resin particles. Next, the resin particles were added to 100 parts by weight of a 1% by weight solution of dimethylamine borane to activate the surface of the resin particles. After 40 parts by weight of the surface-activated resin particles were sufficiently washed with water, they were added to 200 parts by weight of distilled water and dispersed to obtain a dispersion.

  Next, 1 g of an alumina particle slurry (average particle diameter 150 nm) was added to the dispersion over 3 minutes to obtain a suspension containing the substrate particles A to which the core substance was attached. This suspension was placed in 1 L of a solution containing 0.09 mol / L of nickel sulfate and 30 ppm of thallium nitrate to obtain a particle mixture.

  Conductive particles, anisotropic conductive paste, and connection structure were obtained in the same manner as in Example 1 except that the reaction pretreatment step was changed as described above.

(Example 8)
Resin particles (particle diameter: 3.0 μm, base particle B) were prepared by polymerizing divinylbenzene and PTMGA (manufactured by Kyoeisha Chemical Co., Ltd.) at a weight ratio of 3: 7. Conductive particles, an anisotropic conductive paste, and a connected structure were obtained in the same manner as in Example 1 except that the obtained base material particles B were used.

(Example 9)
The surface of a divinylbenzene copolymer resin particle ("Micropearl SP-2025" manufactured by Sekisui Chemical Co., Ltd.) having a particle diameter of 2.5 μm was coated with a silica shell (thickness 250 nm) using a condensation reaction by a sol-gel reaction. Core-shell type organic-inorganic hybrid particles (particle diameter: 3.0 μm, base particle C) were obtained. Conductive particles, an anisotropic conductive paste, and a connection structure were obtained in the same manner as in Example 1 except that the obtained substrate particles C were used.

(Example 10)
In a 500 mL reaction vessel equipped with a stirrer and a thermometer, 300 g of a 0.13% by weight aqueous ammonia solution was placed. Next, 4.1 g of methyltrimethoxysilane, 19.2 g of vinyltrimethoxysilane, and 0.7 g of a silicone alkoxy oligomer ("X-41-1053" manufactured by Shin-Etsu Chemical Co., Ltd.) in an aqueous ammonia solution in a reaction vessel The mixture with was slowly added. After the hydrolysis and condensation reaction proceed with stirring, 2.4 mL of a 25 wt% aqueous ammonia solution is added, and then the particles are isolated from the aqueous ammonia solution, and the particles obtained are subjected to an oxygen partial pressure of 10 ^-17 atm. The mixture was calcined at 350 ° C. for 2 hours to obtain organic-inorganic hybrid particles (base particle D) having a particle diameter of 3.0 μm. A bonded structure was obtained in the same manner as in Example 1 except that the obtained substrate particles D were used.

(Example 11)
Only substrate particle A and a particle diameter differ, and substrate particle E whose particle diameter is 2.5 micrometers was prepared. Conductive particles, an anisotropic conductive paste, and a connection structure were obtained in the same manner as in Example 1 except that the substrate particles E were used.

(Example 12)
Only substrate particle A and a particle diameter differ, and substrate particle F whose particle diameter is 5.0 micrometers was prepared. Conductive particles, an anisotropic conductive paste, and a connection structure were obtained in the same manner as in Example 1 except that the substrate particles F were used.

(Example 13)
Only substrate particle A and a particle diameter differ, and substrate particle F whose particle diameter is 10.0 micrometers was prepared. Conductive particles, an anisotropic conductive paste, and a connection structure were obtained in the same manner as in Example 1 except that the substrate particles G were used.

(Example 14)
100 mmol of methyl methacrylate, N, N, N-trimethyl-N-2-methacryloyloxyethyl in a 1000 mL separable flask equipped with a four-neck separable cover, a stirring blade, a three-way cock, a condenser and a temperature probe A monomer composition containing 1 mmol of ammonium chloride and 1 mmol of 2,2'-azobis (2-amidinopropane) dihydrochloride is weighed in ion-exchanged water so as to have a solid content of 5% by weight, and then 200 rpm Stir and carry out polymerization at 70 ° C. for 24 hours under a nitrogen atmosphere. After completion of the reaction, the resultant was lyophilized to obtain insulating particles having an ammonium group on the surface and having an average particle diameter 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% by weight aqueous dispersion of insulating particles.

  10 g of the conductive particles obtained in Example 1 were dispersed in 500 mL of ion-exchanged water, 4 g of a water 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 resultant was further washed with methanol and dried to obtain conductive particles to which insulating particles are attached.

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

  Conductive particles, an anisotropic conductive paste, and a connection structure were obtained in the same manner as in Example 1 except that the above changes were made. In this manner, a nickel-boron conductive layer (thickness 0.1 μm) was disposed on the surface of the resin particle to obtain particles whose surface is a conductive layer having a protrusion main body.

(Comparative example 1)
Reaction pretreatment:
As the base material particle H, a styrene-silica composite resin particle ("Soriostar" manufactured by Nippon Shokubai Co., Ltd.) having a particle diameter of 3.0 μm was prepared. The mixture was poured into a conditioner aqueous solution ("cleaner conditioner 231" manufactured by Rohm and Haas Electronic Materials Co., Ltd.) with stirring, and dispersed to obtain a dispersion. The dispersion was filtered, and an aqueous stannous chloride solution was added to the recovered particles, and the surface was subjected to a sensitivity treatment to cause tin ions to be adsorbed, to obtain a particle-containing liquid which was subjected to a sensitivity treatment. Subsequently, the particle-containing liquid was filtered, an aqueous palladium chloride solution was added, and activation treatment was performed to trap palladium ions on the surface of the particles, to obtain a first particle mixed liquid.

  Next, 3 L of a nickel plating solution containing 20 g / L of sodium tartrate, 23 g / L of nickel sulfate, and 1.55 g / L of sodium hypophosphite was prepared. The temperature of the nickel plating solution was raised to 60 ° C., the first particle mixture was added, and the mixture was dispersed for 5 minutes to obtain a second particle mixture.

  Subsequently, a nickel plating solution containing 200 g / L of nickel sulfate, 200 g / L of sodium hypophosphite and 90 g / L of sodium hydroxide was prepared. This nickel plating solution was continuously added separately to the second particle mixture at a rate of 3 mL / min by a metering pump. After adding the whole amount of the nickel plating solution, the mixture is stirred for 5 minutes while maintaining the temperature of 60 ° C., filtered, and the filtrate is washed with pure water and dried by a vacuum dryer at 100 ° C. to obtain conductive particles. The Then, in the same manner as in Example 1, conductive particles, an anisotropic conductive paste, and a connection structure were obtained.

(Comparative example 2)
Conductivity is the same as in Example 1 except that the number of repetition of a series of processes of the addition of the sodium borohydride aqueous solution and the dropping of the nickel plating solution is changed from 5 times to 0 times in the protrusion nucleus forming step. Particles, an anisotropic conductive paste and a connection structure were obtained.

(Comparative example 3)
(1) Preparation of conductive particles Reaction pretreatment:
As the base particle A, a divinylbenzene copolymer resin particle ("Micropearl SP-203" manufactured by Sekisui Chemical Co., Ltd.) having a particle diameter of 3.0 μm was prepared.

After dispersing 10 parts by weight of the above resin particles in 100 parts by weight of an alkaline solution containing 5% by weight of a palladium catalyst solution using an ultrasonic disperser, the solution was filtered to take out the resin particles. Next, the resin particles were added to 100 parts by weight of a 1% by weight solution of dimethylamine borane to activate the surface of the resin particles. After 40 parts by weight of the surface-activated resin particles were sufficiently washed with water, they were added to 200 parts by weight of distilled water and dispersed to obtain a dispersion.

Next, 1 g of metal nickel particle slurry ("2020SUS" manufactured by Mitsui Metals Co., Ltd., average particle diameter 150 nm) is added to the above dispersion over 3 minutes, and a suspension containing substrate particles A to which a core substance is attached Obtained. This suspension was placed in 1 L of a solution containing 0.09 mol / L of nickel sulfate and 30 ppm of thallium nitrate to obtain a particle mixture.

Early reaction:
0.49 mol / L nickel sulfate, 0.067 mol / L dimethylamine borane, 0.025 mol / L citric acid, 0.16 mol / L malonic acid, 0.22 mol / L succinic acid, 25 ppm thallium nitrate, and 15 ppm bismuth nitrate 1 L of nickel plating solution (pH 7.2) containing was prepared. The pH was adjusted with aqueous ammonia.

  While stirring the obtained particle mixed solution at 40 ° C., the above-mentioned nickel plating solution was dropped at 60 mL / min, electroless nickel plating was performed, and the particle mixed solution after the initial reaction was obtained.

Late process:
A 2 L nickel plating solution (pH 9.0) containing 0.47 mol / L of dimethylamine borane was prepared. The pH was adjusted with aqueous ammonia.

  The above-mentioned nickel plating solution was dropped at 40 ml / min to the particle mixed solution after the previous reaction step, and electroless nickel plating was performed. Thus, conductive particles were obtained.

  In the reaction pretreatment step, conductive particles, an anisotropic conductive paste, and a connection structure were obtained in the same manner as in Example 1 except that the metal nickel particle slurry was added and the protrusion nucleus forming step was not performed.

(Evaluation)
(1) State of protrusion and conductive part The obtained conductive particles are added to “Knozer 4000“ Technobit 4000 ”so that the content is 30% by weight, and dispersed, and embedded resin for conductive particle inspection Was produced. The cross section of the conductive particles was cut out using an ion milling apparatus ("IM 4000" manufactured by Hitachi High-Technologies Corporation) so as to pass near the center of the dispersed conductive particles in the embedded resin for inspection.

  Then, using a scanning electron microscope (SEM), the image magnification was set to 25,000 times, 10 conductive particles were randomly selected, and protrusions on the outer peripheral surface of each conductive particle were observed. 1) The ratio A of projections having an aspect ratio of 2 or more and 4 or less, 2) The ratio B of projections having an aspect ratio of 3 or more and 4 or less, and 3) The average height of the projections was determined. Moreover, the average thickness of the electroconductive part of the part without 4) protrusion was measured using the transmission electron microscope (TEM).

(2) Evaluation of Surface Grating of Conductive Portion The area intensity ratio of the diffraction line specific to the device depending on the diffraction angle was calculated using an X-ray diffraction device ("RINT 2500 VHF" manufactured by Rigaku Denki Co., Ltd.). The ratio (ratio of (111) planes in X-ray diffraction) of the diffraction peak intensity in the (111) direction to the diffraction peak intensity of the entire diffraction line of the conductive part having a crystal structure was determined.

(3) Connection resistance Measurement of connection resistance:
The connection resistance between opposing electrodes in the obtained connection structure was measured by the four-terminal method. Moreover, connection resistance was evaluated by the following evaluation criteria.

[Evaluation criteria for connection resistance]
○ ○ ○: Connection resistance is 2.0 Ω or less ○ ○: Connection resistance exceeds 2.0 Ω, 3.0 Ω or less ○: Connection resistance exceeds 3.0 Ω, 5.0 Ω or less Δ: Connection resistance is 5.0 Ω Exceeding 10 Ω or less ×: Connection resistance exceeding 10 Ω

  The results are shown in Table 1 below.

  In addition, in the electroconductive particle of Examples 1-14, the processus | protrusion which the some particle | grain connected several pieces in row form was formed was included. In addition, the projection formed by connecting a plurality of particles in a row has a bent portion on the outer peripheral surface. Moreover, in Examples 1-14, the surface area of the part with protrusion was 30% or more in 100% of the total surface area of the outer surface of a conductive part.

1, 11, 21, 31, conductive particles 1a, 11a, 21a, 31a: protrusions 2, base particles 3, 12, 22, 32: conductive portions 3a, 12a, 22a, 32a, protrusions 4: core material 13: Insulating material 22A, 32A: first conductive portion 32Aa: projection 22B, 32B: second conductive portion 22Ba, 32Ba: projection 51: connection structure 52: first connection target member 52a: first electrode 53: Second connection target member 53a second electrode 54 connection portion 54a binder resin

Claims (16)

Substrate particles,
And a conductive portion disposed on the surface of the substrate particle,
The conductive portion has a plurality of protrusions on the outer surface,
Conductive particles in which a proportion of protrusions having an aspect ratio of 2 or more and 4 or less is 20% or more in 100% of the total number of the plurality of protrusions.   The conductive particle according to claim 1, wherein a proportion of projections having an aspect ratio of 3 or more and 4 or less is 10% or more in 100% of the total number of the plurality of projections.   The conductive particle according to claim 1, wherein a proportion of projections having an aspect ratio of 2 or more and 4 or less is 30% or more in 100% of the total number of the plurality of projections.   The conductive particle according to any one of claims 1 to 3, wherein the plurality of protrusions include protrusions formed by connecting a plurality of particles in a row.   The conductive particle according to any one of claims 1 to 4, wherein a protrusion formed by connecting a plurality of particles in a row has a bent portion on the outer peripheral surface.   The conductive particle according to any one of claims 1 to 5, wherein a material of the outer surface of the plurality of protrusions includes nickel. The conductive portion includes a first conductive portion and a second conductive portion disposed on an outer surface of the first conductive portion;
The conductive particle according to any one of claims 1 to 6, wherein at least one of the first conductive portion and the second conductive portion is a conductive portion containing nickel and having a crystal structure.   The conductive particle according to claim 7, wherein in the conductive portion containing nickel and having a crystal structure, the proportion of (111) plane in X-ray diffraction is 80% or more. A core material disposed on the surface of the substrate particles,
The conductive portion is disposed on the surface of the base particle so as to cover the base particle and the core substance, and the core substance is disposed inside the plurality of protrusions.
The core material does not contain a metal, or the main metal contained in the core material is different from the main metal contained in the conductive portion in contact with the core material. Electrically conductive particles as described.   The electroconductive particle of Claim 9 whose Mohs hardness of the material of the said core substance is five or more.   The conductive particle according to any one of claims 1 to 10, wherein an average height of the plurality of protrusions is 50 nm or more and 900 nm or less.   The conductive particle according to any one of claims 1 to 11, wherein the surface area of the portion with the projections is 30% or more in 100% of the total surface area of the outer surface of the conductive portion.   The conductive particle according to any one of claims 1 to 12, wherein the substrate particle is a resin particle or an organic-inorganic hybrid particle.   The electroconductive particle of any one of Claims 1-13 provided with the insulating substance arrange | positioned on the outer surface of the said electroconductive part.   A conductive material comprising the conductive particles according to any one of claims 1 to 14 and a binder resin. A first connection target member having a first electrode on the surface;
A second connection target member having a second electrode on its surface;
A connecting portion connecting the first connection target member and the second connection target member;
The material of the connection portion is the conductive particle according to any one of claims 1 to 14, or a conductive material containing the conductive particle and a binder resin,
The connection structure which the said 1st electrode and the said 2nd electrode are electrically connected by the said electroconductive particle.

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