JP6423687B2 - Conductive particles, conductive materials, and connection structures - Google Patents

Description

  The present invention relates to conductive particles in which a conductive layer containing nickel is disposed on the surface of base particles. The present invention also relates to a conductive material and a connection structure using the conductive particles.

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

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

  For example, when the electrode of the semiconductor chip and the electrode of the glass substrate are electrically connected by the anisotropic conductive material, an anisotropic conductive material containing conductive particles is disposed on the glass substrate. Next, the semiconductor chips are stacked, and heated and pressurized. Accordingly, the anisotropic conductive material is cured, and the electrodes are electrically connected through the conductive particles to obtain a connection structure.

  As an example of the conductive particles, Patent Document 1 below discloses conductive particles in which a silicon-based polymer compound layer, a nickel-phosphorus alloy layer, and a gold layer are formed on the surface of silica particles. Yes. The conductive particles preferably have an internal phosphorus content of 5 to 20%, particularly 8 to 15%, and a surface phosphorus content of 0.5 to 8%, particularly 1 to 5%. It is described.

  Patent Document 2 below discloses conductive particles in which a nickel-phosphorus alloy plating film having a phosphorus component content of 7 to 15% by weight is formed on the surface of spherical core material particles. .

  In the following Patent Document 3, a nickel alloy layer and a silver layer are formed on the surface of a copper particle, and the nickel alloy layer contains phosphorous and / or boron and contains cobalt and / or tungsten. Sex particles are disclosed.

  In the following Patent Document 4, a metal coating layer is formed on the surface of resin particles, and the metal coating layer is formed by an electroless nickel plating process using a boron compound and a hypophosphite compound as a reducing agent. The formed conductive particles are disclosed.

JP 2001-152045 A Japanese Patent Laid-Open No. 7-118866 JP 2002-75057 A JP 2008-41671 A

  When conventional conductive particles as described in Patent Documents 1 to 4 are exposed in the presence of an acid, corrosion of the conductive layer containing nickel may occur. In addition, when a connection structure is obtained by connecting electrodes using conventional conductive particles, the connection resistance between the electrodes increases when the connection structure is exposed to the presence of an acid. There is.

  An object of the present invention is to provide conductive particles in which corrosion of a conductive layer containing nickel hardly occurs in the presence of an acid, and a conductive material and a connection structure using the conductive particles.

  Also, the object of the present invention is to obtain a connection structure by electrically connecting the electrodes with conductive particles, the conductive particles before connection between the electrodes are exposed in the presence of an acid, or An object of the present invention is to provide conductive particles capable of maintaining a low connection resistance even when the connection structure is exposed to the presence of an acid, and a conductive material and a connection structure using the conductive particles.

  According to a wide aspect of the present invention, there are provided base particles and a conductive layer that is disposed on the surface of the base particles and contains nickel, and the conductive layer containing nickel is entirely composed of nickel and phosphorus. In the region of 50% thickness from the inner surface to the outside of the conductive layer containing nickel and tungsten, the average phosphorus content is 10% by weight or more, and from the outer surface of the conductive layer containing nickel In the region having a thickness of 10% toward the inside, conductive particles having an average tungsten content of 5% by weight or more are provided.

  In a specific aspect of the conductive particles according to the present invention, the conductive layer containing nickel has a conductive layer portion having an amorphous structure, and the amorphous structure occupies the entire region of the conductive layer containing nickel. The ratio of the thickness region of the conductive layer portion is 30% or more.

  On the specific situation with the electroconductive particle which concerns on this invention, the average content of nickel in the whole area | region of the electroconductive layer containing the said nickel is 80 to 95 weight%.

  On the specific situation with the electroconductive particle which concerns on this invention, the average content of phosphorus in the whole area | region of the electroconductive layer containing the said nickel is 5 to 20 weight%.

  In a specific aspect of the conductive particles according to the present invention, the average content of tungsten in the entire region of the conductive layer containing nickel is preferably 0.5% by weight or more and 20% by weight or less, more preferably 0. .5 wt% or more and 10 wt% or less.

  On the specific situation with the electroconductive particle which concerns on this invention, the electroconductive layer containing the said nickel has a processus | protrusion on an outer surface.

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

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

  According to a wide aspect of the present invention, the first connection target member, the second connection target member, the connection portion connecting the first connection target member, and the second connection target member; There is provided a connection structure in which the connection part is formed of the above-described conductive particles or is formed of a conductive material containing the conductive particles and a binder resin.

  In the conductive particles according to the present invention, a conductive layer containing nickel is disposed on the surface of the base particle, and the conductive layer containing nickel as a whole contains nickel, phosphorus and tangsten, and In the region where the thickness is 50% from the inner surface to the outer side of the conductive layer containing nickel, the average phosphorus content is 10% by weight or more, and the thickness is 10% from the outer surface to the inner side of the conductive layer containing nickel. In this region, since the average content of tungsten is 5% by weight or more, it is possible to make it difficult to cause corrosion of the conductive layer containing nickel in the presence of an acid.

FIG. 1 is a cross-sectional view showing conductive particles according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing conductive particles according to the second embodiment of the present invention. FIG. 3 is a cross-sectional view showing conductive particles according to the third embodiment of the present invention. FIG. 4 is a schematic diagram for explaining a region where the phosphorus content needs to be 10% by weight or more and a region where the tungsten content needs to be 5% by weight or more in the conductive layer. . FIG. 5 is a front sectional view schematically showing a connection structure using conductive particles according to the first embodiment of the present invention.

  Details of the present invention will be described below.

(Conductive particles)
The electroconductive particle which concerns on this invention is equipped with the base material particle and the electroconductive layer which is arrange | positioned on the surface of this base material particle and contains nickel.

  In the conductive particles according to the present invention, the nickel-containing conductive layer as a whole contains nickel, phosphorus, and tungsten, and a region having a thickness of 50% from the inner surface to the outside of the nickel-containing conductive layer ( In R1), the average content of phosphorus is 10% by weight or more, and in the region (R2) having a thickness of 10% from the outer surface to the inside of the conductive layer containing nickel, the average content of tungsten is 5% by weight. That's it.

  By adopting the above-described configuration in the conductive particles according to the present invention, corrosion of the conductive layer containing nickel can be made difficult to occur in the presence of an acid. Even when the conductive particles are exposed in the presence of an acid, the conductive layer containing nickel is unlikely to corrode, so that the performance of the conductive particles can be maintained high.

  Further, when the connection structure is obtained by electrically connecting the electrodes with the conductive particles according to the present invention, the conductive particles before the connection between the electrodes is exposed in the presence of an acid or the connection structure Even if the body is exposed to the presence of acid, the connection resistance can be kept low. In particular, when the conductive particles are used for electrical connection between the electrodes, the conductive particles are generally compressed. When the conductive particles are compressed, the conductive layer may be cracked. Even if a crack occurs in the conductive layer, the connection resistance can be effectively kept low as a result of suppressing corrosion in the conductive layer.

  Furthermore, since the average content of phosphorus in the region (R1) is relatively large, the magnetism of the entire conductive layer can be reduced. For this reason, electroconductive particle can be used suitably for the use for which nonmagnetism is calculated | required.

  Hereinafter, the present invention will be specifically described with reference to the drawings.

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

  The electroconductive particle 1 shown in FIG. 1 has the base particle 2 and the conductive layer 3 containing nickel. The conductive layer 3 is disposed on the surface of the base particle 2. In the first embodiment, the conductive layer 3 is in contact with the surface of the base particle 2. The conductive particle 1 is a coated particle in which the surface of the base particle 2 is coated with the conductive layer 3.

  In the conductive particles 1, the conductive layer 3 containing nickel is a single conductive layer. In the conductive particles 1, the entire conductive layer 3 containing nickel contains nickel, phosphorus, and tangsten. The average content of phosphorus in the region (R1) of the conductive layer 3 is 10% by weight or more, and the average content of tungsten in the region (R2) of the conductive layer 3 is 5% by weight or more. As shown in FIG. 4 in which a part of the conductive particles shown in FIG. 1 is enlarged, the region (R1) is a region between the inner surface of the conductive layer 3 and the broken line L1. The region (R1) is a region having a thickness ½ in the thickness direction of the conductive layer 3 on the base particle 2 side. The region (R1) is a region having a thickness of ½ from the inner surface of the conductive layer 3 toward the outer side in the thickness direction of the conductive layer 3. The region (R2) is a region between the outer surface of the conductive layer 3 and the broken line L2. The region (R2) is a region having a thickness of 1/10 in the thickness direction on the outer surface side of the conductive layer 3. The region (R2) is a region having a thickness of 1/10 from the outer surface of the conductive layer 3 toward the inside in the thickness direction of the conductive layer 3.

  Unlike the conductive particles 11 and 21 described later, the conductive particles 1 do not have a core substance. The conductive particles 1 do not have protrusions on the surface. The conductive particles 1 are spherical. The conductive layer 3 has no protrusion on the outer surface. Thus, the electroconductive particle which concerns on this invention does not need to have a processus | protrusion on the electroconductive surface, and may be spherical. Moreover, the electroconductive particle 1 does not have an insulating substance unlike the electroconductive particles 11 and 21 mentioned later. However, the conductive particles 1 may have an insulating material disposed on the outer surface of the conductive layer 3. In this case, a conductive layer not containing nickel may be disposed between the conductive layer 3 and the insulating material.

  In the conductive particle 1, the base particle 2 and the conductive layer 3 containing nickel are in contact. A conductive layer not containing nickel may be disposed between the base particle and the conductive layer containing nickel, and the conductive layer not containing nickel is arranged on the outer surface of the conductive layer containing nickel. May be.

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

  A conductive particle 11 shown in FIG. 2 includes a base particle 2, a conductive layer 12 containing nickel, a plurality of core substances 13, and a plurality of insulating substances 14. The conductive layer 12 is disposed on the surface of the base particle 2 so as to be in contact with the base particle 2.

  In the conductive particles 11, the conductive layer 12 containing nickel is a single conductive layer. In the conductive particles 11, the conductive layer 12 containing nickel as a whole contains nickel, phosphorus, and tangsten. The average content of phosphorus in the region (R1) of the conductive layer 12 is 10% by weight or more, and the average content of tungsten in the region (R2) of the conductive layer 12 is 5% by weight or more.

  The conductive particles 11 have a plurality of protrusions 11a on the conductive surface. The conductive layer 12 has a plurality of protrusions 12a on the outer surface. A plurality of core substances 13 are arranged on the surface of the base particle 2. A plurality of core materials 13 are embedded in the conductive layer 12. The core substance 13 is disposed inside the protrusions 11a and 12a. The conductive layer 12 covers a plurality of core materials 13. The outer surface of the conductive layer 12 is raised by a plurality of core materials 13, and protrusions 11 a and 12 a are formed.

  The conductive particles 11 have an insulating substance 14 disposed on the outer surface of the conductive layer 12. At least a part of the outer surface of the conductive layer 12 is covered with an insulating material 14. The insulating substance 14 is made of an insulating material and is an insulating particle. Thus, the electroconductive particle which concerns on this invention may have the insulating substance arrange | positioned on the outer surface of an electroconductive layer. However, the conductive particles according to the present invention do not necessarily have an insulating substance.

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

  The conductive particles 21 shown in FIG. 3 have base material particles 2, a conductive layer 22 containing nickel, a plurality of core materials 13, and a plurality of insulating materials 14. The conductive layer 22 containing nickel as a whole has a first conductive layer 22A on the base particle 2 side and a second conductive layer 22B on the opposite side to the base particle 2 side.

  Only the conductive layer is different between the conductive particles 11 and the conductive particles 21. That is, the conductive particle 11 has a single-layered conductive layer, whereas the conductive particle 21 has a two-layered first conductive layer 22A and a second conductive layer 22B. Yes. The first conductive layer 22A and the second conductive layer 22B are formed as separate conductive layers.

  The first conductive layer 22 </ b> A is disposed on the surface of the base particle 2. 22 A of 1st conductive layers are arrange | positioned between the base particle 2 and the 2nd conductive layer 22B. The first conductive layer 22A is in contact with the base particle 2. Accordingly, the first conductive layer 22A is disposed on the surface of the base particle 2, and the second conductive layer 22B is disposed on the surface of the first conductive layer 22A. The conductive particles 21 have a plurality of protrusions 21a on the conductive surface. The conductive layer 22 has a protrusion 22a on the outer surface. The first conductive layer 22A has a protrusion 22Aa on the outer surface. The second conductive layer 22B has a plurality of protrusions 22Ba on the outer surface.

  In the conductive particles 21, the conductive layer 22 containing nickel is a two-layer conductive layer. In the conductive particles 21, the conductive layer 22 containing nickel as a whole contains nickel, phosphorus, and tangsten. The average content of phosphorus in the region (R1) of the conductive layer 22 is 10% by weight or more, and the average content of tungsten in the region (R2) of the conductive layer 22 is 5% by weight or more. The first conductive layer 22A preferably contains tungsten, but may not contain tungsten. The second conductive layer 22B preferably contains phosphorus, but may not contain phosphorus.

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

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

  The substrate particles are preferably resin particles formed of a resin. When connecting between electrodes using the said electroconductive particle, after arrange | positioning the said electroconductive particle between electrodes, the said electroconductive particle is compressed by crimping | bonding. When the substrate particles are resin particles, the conductive particles are easily deformed during the pressure bonding, and the contact area between the conductive particles and the electrode is increased. For this reason, the conduction | electrical_connection reliability between electrodes becomes high.

  Various organic materials are suitably used as the resin for forming the resin particles. Examples of the resin for forming the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; acrylic resins such as polymethyl methacrylate and polymethyl acrylate; Alkylene terephthalate, polycarbonate, polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polysulfone, polyphenylene Oxide, polyacetal, polyimide, polyamideimide, polyether ether Ketones, polyether sulfones, and polymers such as obtained by a variety of polymerizable monomer having an ethylenically unsaturated group is polymerized with one or more thereof. Since the hardness of the substrate particles can be easily controlled within a suitable range, the resin for forming the resin particles is obtained by polymerizing one or more polymerizable monomers having a plurality of ethylenically unsaturated groups. A polymer is preferred.

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

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

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

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

  In the case where the substrate particles are inorganic particles or organic-inorganic hybrid particles excluding metal, examples of the inorganic material for forming the substrate particles include silica and carbon black. The inorganic substance is preferably not a metal. The particles formed from the silica are not particularly limited. For example, after forming a crosslinked polymer particle by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups, firing may be performed as necessary. The particle | grains obtained by performing are mentioned. Examples of the organic / inorganic hybrid particles include organic / inorganic hybrid particles formed of a crosslinked alkoxysilyl polymer and an acrylic resin.

  When the substrate particles are metal particles, examples of the metal that is a material of the metal particles include silver, copper, nickel, silicon, gold, and titanium. However, the substrate particles are preferably not metal particles, and preferably not copper particles.

  The particle diameter of the substrate particles is preferably 0.1 μm or more, more preferably 1 μm or more, still more preferably 1.5 μm or more, particularly preferably 2 μm or more, preferably 1000 μm or less, more preferably 500 μm or less, and even more preferably. Is not more than 300 μm, more preferably not more than 50 μm, still more preferably not more than 30 μm, particularly preferably not more than 5 μm, most preferably not more than 3 μm. When the particle diameter of the substrate particles is equal to or greater than the lower limit, the contact area between the conductive particles and the electrodes is increased, so that the conduction reliability between the electrodes is further increased and the conductive particles are connected via the conductive particles. The connection resistance between the electrodes is further reduced. Further, when forming the conductive layer on the surface of the base particle by electroless plating, it becomes difficult to aggregate and it becomes difficult to form the aggregated conductive particles. When the particle diameter of the substrate particles is not more than the above upper limit, the conductive particles are easily compressed, the connection resistance between the electrodes is further reduced, and the interval between the electrodes is further reduced.

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

  The particle diameter of the substrate particles is particularly preferably 2 μm or more and 5 μm or less. When the particle diameter of the substrate particles is in the range of 2 to 5 μm, even when the distance between the electrodes is small and the thickness of the conductive layer is increased, small conductive particles can be obtained.

[Conductive layer]
The electroconductive particle which concerns on this invention is equipped with the electroconductive layer containing the nickel arrange | positioned on the surface of a base particle. The nickel-containing conductive layer as a whole contains nickel, phosphorus, and tungsten. Furthermore, in the region (R1) having a thickness of 50% from the inner surface to the outer side of the nickel-containing conductive layer, the average phosphorus content is In the region (R2) having a thickness of 10% or more and from the outer surface to the inside of the conductive layer containing nickel, the average content of tungsten is 5% by weight or more. The conductive layer containing nickel may be referred to as a conductive layer X in the following [conductive layer] column. The conductive layer X including nickel does not include a conductive layer not including nickel, and does not include a conductive layer portion not including nickel. Regarding the phosphorus content in the conductive layer X containing nickel, the conductive layer X preferably has a gradient from the inner surface to the outer side of the conductive layer X. Regarding the phosphorus content in the conductive layer X containing nickel, the conductive layer X preferably has a portion that continuously changes from the inner surface to the outside of the conductive layer X, and the portion that continuously decreases. It is preferable to have. Since the conductive layer X has a phosphorus content gradient, there is no sudden change in the content in the conductive layer X, so that the portion that becomes the starting point of cracking or peeling of the plating can be further reduced.

  From the viewpoint of further preventing the corrosion of the conductive layer in the presence of an acid, the average phosphorus content in the region (R1) is preferably 10% by weight or more, more preferably 13% by weight or more, and still more preferably. 15.5% by weight or more. From the viewpoint of further increasing the conductivity, the phosphorus content in the region (R1) is preferably 30% by weight or less.

  From the viewpoint of effectively suppressing the corrosion of the conductive layer in the presence of an acid, the average phosphorus content in the region (R1) is higher than the average phosphorus content in the entire region (R) of the conductive layer. A large amount is preferable, and it is preferably 1% by weight or more.

  From the viewpoint of further increasing the electrical conductivity, the average content of tungsten in the region (R2) is preferably 0.5% by weight or more, more preferably 5% by weight or more, still more preferably 7% by weight or more, particularly preferably. 10.5% by weight or more. From the viewpoint of further increasing the electrical conductivity, the content of tungsten in the region (R2) is preferably 20% by weight or less, more preferably 17% by weight or less, and still more preferably 15% by weight or less. The average content of tungsten in the region (R2) may be 10% by weight or less.

  From the viewpoint of further effectively increasing the conductivity, the average content of tungsten in the region (R2) is preferably larger than the average content of tungsten in the entire region (R) of the conductive layer. It is preferably 5% by weight or more.

  From the viewpoint of effectively increasing the conductivity, the higher the average nickel content in the entire region (R) of the conductive layer X, the better. Therefore, the average content of nickel in the entire region (R) of the conductive layer X is preferably 65% by weight or more, more preferably 70% by weight or more, still more preferably 75% by weight or more, and further preferably 80% by weight. More preferably, it is 85% by weight or more, particularly preferably 90% by weight or more, and most preferably 95% by weight or more. The average content of nickel in the entire region (R) of the conductive layer X may be 97% by weight or more, 97.5% by weight or more, or 98% by weight or more. The average nickel content in the entire region (R) of the conductive layer X is preferably 99.85% by weight or less, more preferably 99.7% by weight or less, and still more preferably less than 99.45% by weight. The average content of nickel in the entire region (R) of the conductive layer X may be 95% by weight or less. When the average content of nickel in the entire region (R) is not less than the above lower limit, the connection resistance between the electrodes is further reduced. Moreover, when there are few oxide films in the surface of an electrode or a conductive layer, there exists a tendency for the connection resistance between electrodes to become low, so that there is much average content of nickel.

  From the viewpoint of further preventing corrosion of the conductive layer in the presence of an acid, the average phosphorus content in the entire region (R) of the conductive layer X is preferably 5% by weight or more, more preferably 8% by weight. % Or more, preferably 20% by weight or less, more preferably 15% by weight or less.

  From the viewpoint of further effectively increasing the conductivity, the average content of tungsten in the entire region (R) of the conductive layer X is preferably 0.5% by weight or more, more preferably 1% by weight or more, preferably 10%. % By weight or less, more preferably 8% by weight or less.

  The measuring method of each average content of nickel, phosphorus and tungsten in the conductive layer X is not particularly limited, and various known analytical methods can be used. Examples of this measuring method include absorption spectrometry or spectrum analysis. In the above-mentioned absorption analysis method, a flame absorptiometer, an electric heating furnace absorptiometer, or the like can be used. Examples of the spectrum analysis method include a plasma emission analysis method and a plasma ion source mass spectrometry method.

  When measuring the average contents of nickel, phosphorus and tungsten in the conductive layer X, it is preferable to use an ICP emission analyzer. Examples of commercially available ICP emission analyzers include ICP emission analyzers manufactured by HORIBA.

  When measuring each content and each average content of nickel, phosphorus, and tungsten in each region in the thickness direction of the conductive layer X, it is preferable to use an FE-TEM apparatus. As a commercial item of the said FE-TEM apparatus, "JEM-2010" by JEOL Ltd. etc. are mentioned.

  From the viewpoint of further preventing corrosion of the conductive layer in the presence of an acid, the conductive layer X preferably has a conductive layer portion having an amorphous structure. From the viewpoint of making it more difficult for the conductive layer to corrode in the presence of an acid, the ratio of the thickness of the conductive layer portion of the amorphous structure to the entire region of the conductive layer X is preferably 10% or more. More preferably, it is 30% or more, and further preferably 50% or more.

  The total thickness of the conductive layer X is preferably 0.005 μm or more, more preferably 0.01 μm or more, still more preferably 0.05 μm or more, preferably 1 μm or less, more preferably 0.3 μm or less. When the total thickness of the conductive layer X is not less than the above lower limit and not more than the above upper limit, sufficient conductivity can be obtained, and the conductive particles do not become too hard, and the conductive particles are not connected at the time of connection between the electrodes. Deforms sufficiently.

  The total thickness of the conductive layer X is particularly preferably 0.05 μm or more and 0.3 μm or less. Furthermore, it is particularly preferable that the particle diameter of the base material particle is 2 μm or more and 5 μm or less, and the total thickness of the conductive layer X is 0.05 μm or more and 0.3 μm or less. In this case, the conductive particles can be suitably used for applications in which a large current flows. Furthermore, when the conductive particles are compressed to connect the electrodes, it is possible to further suppress the electrodes from being damaged.

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

  The conductive layer X may contain boron in addition to nickel, phosphorus, and tungsten. The conductive layer X may contain a metal other than nickel. Examples of the metal other than nickel in the conductive layer X include gold, silver, copper, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, palladium, chromium, seaborgium, titanium, antimony, bismuth, thallium, Examples thereof include germanium, cadmium, silicon, molybdenum, tin-doped indium oxide (ITO), and solder. As for these metals, only 1 type may be used and 2 or more types may be used together. In the conductive layer X, when a plurality of metals are included, the plurality of metals may be alloyed.

  The method for forming the conductive layer on the surface of the substrate particles is not particularly limited. As a method for forming the conductive layer, for example, a method by electroless plating, a method by electroplating, a method by physical vapor deposition, and a paste containing metal powder or metal powder and a binder is used for base particles or other conductive layers. For example, a method of coating the surface. Especially, since formation of a conductive layer is simple, the method by electroless plating is preferable. Examples of the method by physical vapor deposition include methods such as vacuum vapor deposition, ion plating, and ion sputtering.

  The particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 100 μm or less, more preferably 20 μm or less, still more preferably 5 μm or less, and particularly preferably 3 μm or less. When the particle diameter of the conductive particles is not less than the above lower limit and not more than the upper limit, when the electrodes are connected using the conductive particles, the contact area between the conductive particles and the electrode is sufficiently large, and the conductive layer is formed. Aggregated conductive particles are less likely to be formed during formation. Further, the distance between the electrodes connected via the conductive particles does not become too large, and the conductive layer is difficult to peel from the surface of the base material particles. The particle diameter of the conductive particles is also preferably 3 μm or less.

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

  The conductive layer X may be formed of a single layer, or may be formed of a plurality of layers, and a crystal grain boundary exists only in a part of the conductive layer X to form a discontinuous layer. May be. The conductive layer X may have a laminated structure of two or more layers. In addition to the conductive layer X, the conductive particles may include a gold layer, a nickel layer, a palladium layer, a copper layer, or an alloy layer containing tin and silver as the outermost layer.

  As a method for controlling each content and each average content of nickel, phosphorus and tungsten in each region of the conductive layer X, for example, when forming the conductive layer X by electroless nickel plating, the pH of the nickel plating solution Control method, method of adjusting the concentration of the phosphorus-containing reducing agent when forming the conductive layer X by electroless nickel plating, method of adjusting the tungsten concentration in the nickel plating solution, and the nickel concentration in the nickel plating solution The method of adjusting etc. are mentioned.

  In the method of forming by electroless plating, generally, a catalyzing step and an electroless plating step are performed. Hereinafter, an example of a method for forming an alloy plating layer containing nickel, phosphorus, and tungsten on the surface of the resin particles 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 particles.

  As a method for forming the catalyst on the surface of the resin particles, for example, after adding the resin particles to a solution containing palladium chloride and tin chloride, the surface of the resin particles is activated with an acid solution or an alkali solution, A method of depositing palladium on the surface of the resin particles, and after adding the resin particles to a solution containing palladium sulfate and aminopyridine, the surface of the resin particles is activated by a solution containing a reducing agent. Examples thereof include a method of depositing palladium on the surface. A phosphorus-containing reducing agent is used as the reducing agent. Moreover, the conductive layer X containing phosphorus can be formed by using a phosphorus containing reducing agent as said reducing agent.

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

  By immersing the resin particles in the nickel plating bath, nickel can be deposited on the surface of the resin particles on which the catalyst is formed, and the conductive layer X 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. 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 compound include tungsten boride and sodium tungstate.

  As the complexing agent, monocarboxylic acid complexing agents such as sodium acetate and sodium propionate; dicarboxylic acid complexing agents such as disodium malonate; tricarboxylic acid complexing agents such as disodium succinate; lactic acid, DL-malic acid, Rochelle salt, hydroxy acid complexing agents such as sodium citrate and sodium gluconate; amino acid complexing agents such as glycine and EDTA; amine complexing agents such as ethylenediamine; organic acids such as maleic acid It is preferable to use a complexing agent; and at least one complexing agent selected from the group consisting of these salts.

  As the stabilizer, a lead compound, a bismuth compound or a thallium compound may be added. Specific examples of these compounds include sulfates, carbonates, acetates, nitrates and hydrochlorides of metals (lead, bismuth, thallium) constituting the compounds. Considering the influence on the environment, it is preferable to use at least one of a bismuth compound and a thallium compound.

  Preferred examples of the method of increasing the phosphorus content in the nickel plating layer include a method of lowering the pH of the plating solution and slowing the reaction rate of the nickel plating solution, a method of lowering the temperature of the nickel plating solution, Examples thereof include a method for increasing the concentration of the phosphorus-containing reducing agent and a method for increasing the concentration of the complexing agent in the nickel plating solution. These methods may be used alone or in combination of two or more.

  In the nickel plating process, for example, when the pH in the nickel plating solution is controlled to slow the reaction rate and the concentration of the phosphorus-containing reducing agent in the nickel plating solution is increased, the nickel deposition rate is slowed, Production of phosphite ions or phosphate ions as a product is accelerated. For this reason, a large amount of phosphorus is taken into the plating layer, and a metal plating layer having a high phosphorus content is formed. Such a metal plating layer not only has high corrosion resistance due to its high phosphorus content, but also has a uniform and dense metal plating layer with no irregularities, so the adhesion between the metal plating layer and the substrate particles is high. Become.

[Core material]
The conductive particles preferably have protrusions on the conductive surface. The conductive layer preferably has a protrusion on the outer surface. It is preferable that there are a plurality of protrusions. An oxide film is often formed on the surface of the electrode connected by the conductive particles. Furthermore, an oxide film is often formed on the surface of the conductive layer of the conductive particles. By using the conductive particles having the protrusions, the oxide film is effectively eliminated by the protrusions by placing the conductive particles between the electrodes and then pressing them. For this reason, an electrode and electroconductive particle can be contacted still more reliably and the connection resistance between electrodes can be made low. Furthermore, when the conductive particles have an insulating material on the surface, or when the conductive particles are dispersed in a binder resin and used as a conductive material, the conductive particles and the electrodes are separated by protrusions of the conductive particles. The resin in between can be effectively eliminated. For this reason, the conduction | electrical_connection reliability between electrodes can be improved.

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

  As the method for forming the protrusions, a core material is attached to the surface of the base particle, and then a conductive layer is formed by electroless plating, and a conductive layer is formed on the surface of the base particle by electroless plating. Thereafter, a method of attaching a core substance and further forming a conductive layer by electroless plating may be used. As another method for forming the protrusion, a first conductive layer is formed on the surface of the base particle, and then a core substance is disposed on the first conductive layer, and then the second conductive layer. And a method of adding a core substance in the middle of forming the conductive layer on the surface of the base particle.

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

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

  The average diameter (average particle diameter) of the core substance is preferably 0.001 μm or more, more preferably 0.05 μm or more, preferably 0.9 μm or less, more preferably 0.2 μm or less. When the average diameter of the core substance is not less than the above lower limit and not more than the above upper limit, the connection resistance between the electrodes is effectively reduced.

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

  The number of the protrusions per conductive particle is preferably 3 or more, more preferably 5 or more. The upper limit of the number of protrusions is not particularly limited. The upper limit of the number of protrusions can be appropriately selected in consideration of the particle diameter of the conductive particles.

  The average height of the plurality of protrusions is preferably 0.001 μm or more, more preferably 0.05 μm or more, preferably 0.9 μm or less, more preferably 0.2 μm or less. When the average height of the protrusions is not less than the above lower limit and not more than the above upper limit, the connection resistance between the electrodes is effectively reduced.

  The height of the projection is a virtual line of the conductive portion (dashed line shown in FIG. 2) on the assumption that there is no projection on the line connecting the center of the conductive particles and the tip of the projection (dashed line L1 shown in FIG. 2). L2) Indicates the distance from the top (on the outer surface of the spherical conductive particles assuming no projection) to the tip of the projection. That is, in FIG. 2, the distance from the intersection of the broken line L1 and the broken line L2 to the tip of the protrusion is shown.

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

  The insulating substance is preferably an insulating particle because the insulating substance can be more easily removed when the electrodes are pressed.

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

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

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

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

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

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

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

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

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

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

  The conductive material and the binder resin preferably contain a thermoplastic component or a thermosetting component. The conductive material and the binder resin may contain a thermoplastic component or may contain a thermosetting component. The conductive material and the binder resin preferably contain a thermosetting component. The thermosetting component preferably contains a curable compound that can be cured by heating and a thermosetting agent. The thermosetting agent is preferably a thermal cation curing initiator. The curable compound curable by heating and the thermosetting agent are used in an appropriate blending ratio so that the binder resin is cured. When the binder resin contains a thermal cation curing initiator, an acid is easily contained in the cured product. However, the connection resistance between the electrodes can be kept low by using the conductive particles according to the present invention.

  In addition to the conductive particles and the binder resin, the conductive material includes, for example, a filler, an extender, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, and a light stabilizer. Various additives such as an agent, an ultraviolet absorber, a lubricant, an antistatic agent and a flame retardant may be contained.

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

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

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

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

  The connection structure includes a first connection target member, a second connection target member, and a connection portion connecting the first and second connection target members, and the connection portion is a conductive member of the present invention. It is preferable that the connection structure be formed of conductive particles or formed of a conductive material containing the conductive particles and a binder resin. In the case where conductive particles are used, the connection portion itself is conductive particles. That is, the first and second connection target members are connected by the conductive particles.

  In FIG. 5, the connection structure using the electroconductive particle which concerns on the 1st Embodiment of this invention is typically shown with front sectional drawing.

  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 particles 1. In FIG. 5, the conductive particles 1 are schematically shown for convenience of illustration. Instead of the conductive particles 1, conductive particles 11, 21, etc. may be used.

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

The manufacturing method of the connection structure is not particularly limited. As an example of the manufacturing method of the connection structure, the conductive material is disposed between the first connection target member and the second connection target member to obtain a multilayer body, and then the multilayer body is heated. And a method of applying pressure. The pressure of the said pressurization is about 9.8 * 10 < ⁴ > -4.9 * 10 < ⁶ > Pa. The temperature of the said heating is about 120-220 degreeC.

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

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

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

Example 1
Divinylbenzene copolymer resin particles having a particle size of 3.0 μm (“Micropearl SP-203” manufactured by Sekisui Chemical Co., Ltd.) were prepared. After dispersing 10 parts by weight of the 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 resin particles were taken out by filtering the solution. Next, the resin particles were added to 100 parts by weight of a 1% by weight dimethylamine borane solution to activate the surface of the resin particles. The resin particles whose surface was activated were sufficiently washed with water, and then added to 500 parts by weight of distilled water and dispersed to obtain a suspension A.

  In addition, as a nickel plating solution for the previous process, a mixed solution of nickel sulfate 500 g / L, sodium hypophosphite 150 g / L, sodium citrate 150 g / L, and plating stabilizer 6 ml / L was adjusted to pH 8 with ammonia. A plating solution was prepared. 150 ml of this plating solution was added dropwise to the suspension A through a metering pump at an addition rate of 20 ml / min. The reaction temperature was set to 50 ° C. Then, it stirred until pH was stabilized, it confirmed that hydrogen foaming stopped, and the electroless-plating first stage process was performed.

  Next, as a nickel plating solution for the latter process, a plating solution prepared by adjusting a mixed solution of nickel sulfate 500 g / L, dimethylamine borane 80 g / L and sodium tungstate 10 g / L to pH 11.0 with sodium hydroxide is prepared. did. 350 ml of this plating solution was added dropwise to the suspension through a metering pump at an addition rate of 10 ml / min. The reaction temperature was set at 30 ° C. Then, it stirred until pH was stabilized, it confirmed that the foaming of hydrogen stopped, and the electroless-plating late process was performed.

  Thereafter, by filtering the suspension, the particles were taken out, washed with water, and dried to obtain conductive particles having a nickel-tungsten-phosphorus conductive layer disposed on the surface of the resin particles.

  When the cross section of the obtained particles was measured with TEM-EDX to confirm the phosphorus content, the conductive layer had a content gradient from the inner surface to the outer side of the conductive layer.

(Example 2)
Suspension A of Example 1 was prepared.

  As a nickel plating solution for the first step, a plating solution in which a mixed solution of nickel sulfate 500 g / L, sodium hypophosphite 250 g / L, sodium citrate 150 g / L, and plating stabilizer 6 ml / L is adjusted to pH 6 with ammonia. Prepared. 200 ml of this plating solution was added dropwise to the suspension A through a metering pump at an addition rate of 20 ml / min. The reaction temperature was set to 50 ° C. Then, it stirred until pH was stabilized, it confirmed that hydrogen foaming stopped, and the electroless-plating first stage process was performed.

  Next, as a nickel plating solution for the latter process, a plating solution prepared by adjusting a mixed solution of nickel sulfate 150 g / L, dimethylamine borane 80 g / L, and sodium tungstate 10 g / L to pH 11.0 with sodium hydroxide is prepared. did. 300 ml of this plating solution was dropped into the suspension through a metering pump at an addition rate of 10 ml / min. The reaction temperature was set at 30 ° C. Then, it stirred until pH was stabilized, it confirmed that the foaming of hydrogen stopped, and the electroless-plating late process was performed.

  Thereafter, by filtering the suspension, the particles were taken out, washed with water, and dried to obtain conductive particles having a nickel-tungsten-phosphorus conductive layer disposed on the surface of the resin particles.

  Conductive particles were obtained in the same manner as in Example 1 except that the conductive layer was formed by the above plating method.

  When the cross section of the obtained particles was measured with TEM-EDX to confirm the phosphorus content, the conductive layer had a content gradient from the inner surface to the outer side of the conductive layer.

(Example 3)
Suspension A of Example 1 was prepared.

  As a nickel plating solution for the previous process, a plating solution in which a mixed solution of nickel sulfate 500 g / L, sodium hypophosphite 150 g / L, sodium citrate 150 g / L, and plating stabilizer 6 ml / L is adjusted to pH 8 with ammonia. Prepared. 250 ml of this plating solution was added dropwise to the suspension A through a metering pump at an addition rate of 20 ml / min. The reaction temperature was set to 50 ° C. Then, it stirred until pH was stabilized, it confirmed that hydrogen foaming stopped, and the electroless-plating first stage process was performed.

  Next, as a nickel plating solution for the latter process, a plating solution prepared by adjusting a mixed solution of nickel sulfate 150 g / L, dimethylamine borane 80 g / L, and sodium tungstate 20 g / L to pH 11.0 with sodium hydroxide is prepared. did. 250 ml of this plating solution was added dropwise to the suspension through a metering pump at an addition rate of 10 ml / min. The reaction temperature was set at 30 ° C. Then, it stirred until pH was stabilized, it confirmed that the foaming of hydrogen stopped, and the electroless-plating late process was performed.

  Thereafter, by filtering the suspension, the particles were taken out, washed with water, and dried to obtain conductive particles having a nickel-tungsten-phosphorus conductive layer disposed on the surface of the resin particles.

  Conductive particles were obtained in the same manner as in Example 1 except that the conductive layer was formed by the above plating method.

  When the cross section of the obtained particles was measured with TEM-EDX to confirm the phosphorus content, the conductive layer had a content gradient from the inner surface to the outer side of the conductive layer.

Example 4
Suspension A of Example 1 was prepared.

  As a nickel plating solution for the first step, a plating solution in which a mixed solution of nickel sulfate 500 g / L, sodium hypophosphite 250 g / L, sodium citrate 150 g / L, and plating stabilizer 6 ml / L is adjusted to pH 6 with ammonia. Prepared. 300 ml of this plating solution was added dropwise to the suspension A through a metering pump at an addition rate of 20 ml / min. The reaction temperature was set to 50 ° C. Then, it stirred until pH was stabilized, it confirmed that hydrogen foaming stopped, and the electroless-plating first stage process was performed.

  Next, as a nickel plating solution for the latter process, a plating solution prepared by adjusting a mixed solution of nickel sulfate 150 g / L, dimethylamine borane 80 g / L, and sodium tungstate 20 g / L to pH 11.0 with sodium hydroxide is prepared. did. 200 ml of this plating solution was added dropwise to the suspension through a metering pump at an addition rate of 10 ml / min. The reaction temperature was set at 30 ° C. Then, it stirred until pH was stabilized, it confirmed that the foaming of hydrogen stopped, and the electroless-plating late process was performed.

  Thereafter, by filtering the suspension, the particles were taken out, washed with water, and dried to obtain conductive particles having a nickel-tungsten-phosphorus conductive layer disposed on the surface of the resin particles.

  Conductive particles were obtained in the same manner as in Example 1 except that the conductive layer was formed by the above plating method.

  When the cross section of the obtained particles was measured with TEM-EDX to confirm the phosphorus content, the conductive layer had a content gradient from the inner surface to the outer side of the conductive layer.

(Example 5)
Base material particles similar to those in Example 1 were prepared. After dispersing 10 parts by weight of the 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 resin particles were taken out by filtering the solution. Next, the resin particles were added to 100 parts by weight of a 1% by weight dimethylamine borane solution to activate the surface of the resin particles. The resin particles whose surface was activated were sufficiently washed with water, and then added to 500 parts by weight of distilled water and dispersed to obtain a suspension. Next, 1 g of metallic nickel particle slurry (average particle size 100 nm) was added to the dispersion over 3 minutes to obtain base particles to which the core substance was adhered. Suspension was obtained by adding the base material particle | grains to which the core substance was adhered to 500 weight part of distilled water, and making it disperse | distribute. Conductive particles were obtained in the same manner as in Example 1 except that the base particles were changed to base particles to which the core substance was attached.

  When the cross section of the obtained particles was measured with TEM-EDX to confirm the phosphorus content, the conductive layer had a content gradient from the inner surface to the outer side of the conductive layer.

(Example 6)
To a 1000 mL separable flask equipped with a four-neck separable cover, stirring blade, three-way cock, condenser and temperature probe, 100 mmol of methyl methacrylate and N, N, N-trimethyl-N-2-methacryloyloxyethyl A monomer composition containing 1 mmol of ammonium chloride and 1 mmol of 2,2′-azobis (2-amidinopropane) dihydrochloride was weighed in ion-exchanged water so that the solid content was 5% by weight, and then at 200 rpm. The mixture was stirred and polymerized at 70 ° C. for 24 hours under a nitrogen atmosphere. After completion of the reaction, it was freeze-dried to obtain insulating particles having an ammonium group on the surface, an average particle size of 220 nm, and a CV value of 10%.

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

  10 g of the conductive particles obtained in Example 5 were dispersed in 500 mL of ion-exchanged water, 4 g of an aqueous dispersion of insulating particles was added, and the mixture was stirred at room temperature for 6 hours. After filtration through a 0.3 μm mesh filter, the particles were further washed with methanol and dried to obtain conductive particles having insulating particles attached thereto.

  When observed with a scanning electron microscope (SEM), only one coating layer of insulating particles was formed on the surface of the conductive particles. The coverage of the insulating particles with respect to the area of 2.5 μm from the center of the conductive particles by image analysis (that is, the projected area of the particle diameter of the insulating particles) was calculated to be 40%.

  When the cross section of the obtained particles was measured with TEM-EDX to confirm the phosphorus content, the conductive layer had a content gradient from the inner surface to the outer side of the conductive layer.

(Example 7)
The divinylbenzene copolymer resin particles having a particle diameter of 3.0 μm were changed to divinylbenzene copolymer resin particles having a particle diameter of 2.0 μm, thereby the thickness of the entire region of the conductive layer, and each region Conductive particles were obtained in the same manner as in Example 1 except that the average content of was changed as shown in Table 1 below. When the cross section of the obtained particles was measured with TEM-EDX to confirm the phosphorus content, the conductive layer had a content gradient from the inner surface to the outer side of the conductive layer.

(Example 8)
The divinylbenzene copolymer resin particles having a particle diameter of 3.0 μm were changed to divinylbenzene copolymer resin particles having a particle diameter of 5.0 μm, whereby the average content in each region is shown in Table 1 below. Conductive particles were obtained in the same manner as in Example 1 except that changes were made. When the cross section of the obtained particles was measured with TEM-EDX to confirm the phosphorus content, the conductive layer had a content gradient from the inner surface to the outer side of the conductive layer.

Example 9
The divinylbenzene copolymer resin particles having a particle size of 3.0 μm were changed to organic-inorganic hybrid particles having a particle size of 3.0 μm and a copolymer of divinylbenzene and a siloxane having a vinyl group. Conductive particles were obtained in the same manner as in Example 1 except that the thickness of the entire region and the average content in each region were changed as shown in Table 1 below. When the cross section of the obtained particles was measured with TEM-EDX to confirm the phosphorus content, the conductive layer had a content gradient from the inner surface to the outer side of the conductive layer.

(Example 10)
The nickel powder (average particle size of 50 nm) generated in the plating bath by the plating reaction was changed to adhere to the base particles without adding the metal nickel particle slurry, and thereby the entire area of the conductive layer was changed. Conductive particles were obtained in the same manner as in Example 5 except that the thickness and the average content in each region were changed as shown in Table 1 below. When the cross section of the obtained particles was measured with TEM-EDX to confirm the phosphorus content, the conductive layer had a content gradient from the inner surface to the outer side of the conductive layer.

(Example 11)
Base material particles similar to those in Example 1 were prepared. After dispersing 10 parts by weight of the 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 resin particles were taken out by filtering the solution. Next, the resin particles were added to 100 parts by weight of a 1% by weight dimethylamine borane solution to activate the surface of the resin particles. The resin particles whose surface was activated were sufficiently washed with water, and then added to 500 parts by weight of distilled water and dispersed to obtain a suspension. Next, 1 g of metallic nickel particle slurry (average particle size 100 nm) was added to the dispersion over 3 minutes to obtain base particles to which the core substance was adhered. Suspension was obtained by adding the base material particle | grains to which the core substance was adhered to 500 weight part of distilled water, and making it disperse | distribute. Conductive particles were obtained in the same manner as in Example 4 except that the base particles were changed to base particles to which the core substance was attached.

  When the cross section of the obtained particles was measured with TEM-EDX to confirm the phosphorus content, the conductive layer had a content gradient from the inner surface to the outer side of the conductive layer.

(Example 12)
10 g of the conductive particles obtained in Example 11 were dispersed in 500 mL of ion-exchanged water, 4 g of an aqueous dispersion of insulating particles obtained in Example 6 was added, and the mixture was stirred at room temperature for 6 hours. After filtration through a 0.3 μm mesh filter, the particles were further washed with methanol and dried to obtain conductive particles having insulating particles attached thereto.

  When observed with a scanning electron microscope (SEM), only one coating layer of insulating particles was formed on the surface of the conductive particles. The coverage of the insulating particles with respect to the area of 2.5 μm from the center of the conductive particles by image analysis (that is, the projected area of the particle diameter of the insulating particles) was calculated to be 40%. When the cross section of the obtained particles was measured with TEM-EDX to confirm the phosphorus content, the conductive layer had a content gradient from the inner surface to the outer side of the conductive layer.

(Example 13)
Suspension A of Example 1 was prepared. As a nickel plating solution for the previous process, a plating solution in which a mixed solution of nickel sulfate 500 g / L, sodium hypophosphite 150 g / L, sodium citrate 150 g / L, and plating stabilizer 6 ml / L is adjusted to pH 8 with ammonia. Prepared. 150 ml of this plating solution was added dropwise to the suspension A through a metering pump at an addition rate of 20 ml / min. The reaction temperature was set to 50 ° C. Then, it stirred until pH was stabilized, it confirmed that hydrogen foaming stopped, and the electroless-plating first stage process was performed. Next, the liquid was filtered and washed, and then dried in a vacuum dryer at 70 ° C. for 5 hours to obtain particles on which the previous plating film was formed.

  Next, as a nickel plating solution for the latter process, a plating solution prepared by adjusting a mixed solution of nickel sulfate 500 g / L, dimethylamine borane 80 g / L and sodium tungstate 10 g / L to pH 11.0 with sodium hydroxide is prepared. did. After the particles on which the plating film was formed were dispersed in 200 ml of distilled water, 350 ml of this plating solution was added dropwise to the suspension through a metering pump at an addition rate of 10 ml / min. The reaction temperature was set at 30 ° C. Then, it stirred until pH was stabilized, it confirmed that the foaming of hydrogen stopped, and the electroless-plating late process was performed. Thereafter, by filtering the suspension, the particles were taken out, washed with water, and dried to obtain conductive particles in which nickel-tungsten-phosphorus conductive layers were discontinuously arranged on the surfaces of the resin particles.

  When the cross section of the obtained particle was measured with TEM-EDX and the content of phosphorus was confirmed, only the pre-plated film layer of the conductive layer had a content gradient from the inner surface to the outer side. It was.

(Comparative Example 1)
Suspension A of Example 1 was prepared.

  As a nickel plating solution for the previous process, a plating solution in which a mixed solution of nickel sulfate 500 g / L, sodium hypophosphite 150 g / L, sodium citrate 150 g / L, and plating stabilizer 6 ml / L is adjusted to pH 9 with ammonia. Prepared. 125 ml of this plating solution was added dropwise to the suspension A through a metering pump at an addition rate of 20 ml / min. The reaction temperature was set to 50 ° C. Then, it stirred until pH was stabilized, it confirmed that hydrogen foaming stopped, and the electroless-plating first stage process was performed.

  Next, as a nickel plating solution for the latter process, a plating solution prepared by adjusting a mixed solution of nickel sulfate 150 g / L, dimethylamine borane 80 g / L, and sodium tungstate 10 g / L to pH 11.0 with sodium hydroxide is prepared. did. 325 ml of this plating solution was added dropwise to the suspension through a metering pump at an addition rate of 10 ml / min. The reaction temperature was set at 30 ° C. Then, it stirred until pH was stabilized, it confirmed that the foaming of hydrogen stopped, and the electroless-plating late process was performed.

  Thereafter, by filtering the suspension, the particles were taken out, washed with water, and dried to obtain conductive particles having a nickel-tungsten-phosphorus conductive layer disposed on the surface of the resin particles.

  Conductive particles were obtained in the same manner as in Example 1 except that the conductive layer was formed by the above plating method.

(Comparative Example 2)
Suspension A of Example 1 was prepared.

  As a nickel plating solution for the previous process, a plating solution in which a mixed solution of nickel sulfate 500 g / L, sodium hypophosphite 150 g / L, sodium citrate 150 g / L, and plating stabilizer 6 ml / L is adjusted to pH 8 with ammonia. Prepared. 125 ml of this plating solution was added dropwise to the suspension A through a metering pump at an addition rate of 20 ml / min. The reaction temperature was set to 50 ° C. Then, it stirred until pH was stabilized, it confirmed that hydrogen foaming stopped, and the electroless-plating first stage process was performed.

  Next, as a nickel plating solution for the latter process, a plating solution prepared by adjusting a mixed solution of nickel sulfate 150 g / L, dimethylamine borane 80 g / L, and sodium tungstate 5 g / L to pH 11.0 with sodium hydroxide is prepared. did. 325 ml of this plating solution was added dropwise to the suspension through a metering pump at an addition rate of 10 ml / min. The reaction temperature was set at 30 ° C. Then, it stirred until pH was stabilized, it confirmed that the foaming of hydrogen stopped, and the electroless-plating late process was performed.

  Thereafter, by filtering the suspension, the particles were taken out, washed with water, and dried to obtain conductive particles having a nickel-tungsten-phosphorus conductive layer disposed on the surface of the resin particles.

  Conductive particles were obtained in the same manner as in Example 1 except that the conductive layer was formed by the above plating method.

(Comparative Example 3)
Suspension A of Example 1 was prepared.

  As a nickel plating solution for the previous process, a plating solution in which a mixed solution of nickel sulfate 500 g / L, sodium hypophosphite 150 g / L, sodium citrate 150 g / L, and plating stabilizer 6 ml / L is adjusted to pH 9 with ammonia. Prepared. 100 ml of this plating solution was added dropwise to the suspension A through a metering pump at an addition rate of 20 ml / min. The reaction temperature was set to 50 ° C. Then, it stirred until pH was stabilized, it confirmed that hydrogen foaming stopped, and the electroless-plating first stage process was performed.

  Next, as a nickel plating solution for the latter process, a plating solution prepared by adjusting a mixed solution of nickel sulfate 150 g / L, dimethylamine borane 80 g / L, and sodium tungstate 5 g / L to pH 11.0 with sodium hydroxide is prepared. did. 400 ml of this plating solution was added dropwise to the suspension through a metering pump at an addition rate of 10 ml / min. The reaction temperature was set at 30 ° C. Then, it stirred until pH was stabilized, it confirmed that the foaming of hydrogen stopped, and the electroless-plating late process was performed.

  Thereafter, by filtering the suspension, the particles were taken out, washed with water, and dried to obtain conductive particles having a nickel-tungsten-phosphorus conductive layer disposed on the surface of the resin particles.

  Conductive particles were obtained in the same manner as in Example 1 except that the conductive layer was formed by the above plating method.

(Evaluation)
(1) Average content of nickel, phosphorus, tungsten and boron in the entire region of the conductive layer containing nickel Add 5 g of conductive particles to a mixed solution of 5 mL of 60% nitric acid and 10 mL of 37% hydrochloric acid, and complete the conductive layer To obtain a solution. Using the obtained solution, the contents of nickel, phosphorus, tungsten and boron were analyzed with an ICP-MS analyzer (manufactured by Hitachi, Ltd.).

(2) Average content of nickel, phosphorus, tungsten and boron in the thickness direction of the conductive layer containing nickel The distribution of the content of nickel, phosphorus, tungsten and boron in the thickness direction of the conductive layer containing nickel was measured.

  Using a focused ion beam, a thin film slice of the obtained conductive particles was prepared. Using a transmission electron microscope FE-TEM (“JEM-2010FEF” manufactured by JEOL Ltd.), each of nickel, phosphorus and tungsten in the thickness direction of the conductive layer containing nickel was measured by an energy dispersive X-ray analyzer (EDS). The content was measured. From this result, in the region (R1) of the conductive layer containing nickel (region having a thickness of 50% on the inner surface side) and the region (R2) of the conductive layer containing nickel (region having a thickness of 10% on the outer surface side) The average contents of nickel, phosphorus, tungsten and boron were determined.

(3) Presence state of conductive layer portion of amorphous structure in conductive layer containing nickel (ratio of thickness region)
The presence or absence of a conductive layer portion having an amorphous structure in the conductive layer containing nickel, and the ratio of the region of the thickness of the conductive layer portion having an amorphous structure to the entire region of the conductive layer containing nickel were evaluated. Whether or not it has an amorphous structure is determined by conducting a mapping measurement of the crystal orientation of the cross section of the conductive particles using SEM-EBSD (“JSM-7100F” manufactured by JEOL Ltd.) and confirming the mapping region. Judged.

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

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

  On the upper surface of the glass substrate, the anisotropic conductive paste immediately after fabrication was applied to a thickness of 20 μm to form an anisotropic conductive material layer. Next, the semiconductor chip was stacked on the upper surface of the anisotropic conductive material layer so that the electrodes face each other. Then, while adjusting the temperature of the head so that the temperature of the anisotropic conductive material layer becomes 170 ° C., a pressure heating head is placed on the upper surface of the semiconductor chip and a pressure of 2.5 MPa is applied to apply the anisotropic conductive material. The material layer was cured at 170 ° C. to obtain a connection structure.

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

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

(5) Connection resistance B after being exposed to the presence of acid
The connection structure obtained by the above (4) evaluation of the initial connection resistance A was left for 100 hours in a high-temperature and high-humidity tank at 85 ° C. and a humidity of 85%. By leaving the connection structure under the above conditions, the connection portion between the electrodes in the connection structure is exposed to the presence of acid for a certain period due to the reaction between the water that has penetrated into the binder resin and the acid contained in the binder resin. It was done. In the connection structure after being left, the connection resistance between the opposing electrodes of the connection structure was measured by a four-terminal method. Moreover, the connection resistance B after being exposed to the presence of an acid was determined according to the following criteria.

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

  The results are shown in Table 1 below. The results of connection resistance B after being exposed to the presence of an acid were excellent in the order of Example 4> Examples 2, 3> Example 1.

DESCRIPTION OF SYMBOLS 1 ... Conductive particle 2 ... Base particle 3 ... Conductive layer containing nickel 11 ... Conductive particle 11a ... Protrusion 12 ... Conductive layer containing nickel 12a ... Protrusion 13 ... Core substance 14 ... Insulating substance 21 ... Conductive particle 21a ... Protrusions 22 ... Nickel-containing conductive layer 22a ... Protrusions 22A ... First conductive layer 22Aa ... Protrusions 22B ... Second conductive layers 22Ba ... Protrusions 51 ... Connection structure 52 ... First connection object member 52a ... First Electrode 53 ... second connection target member 53a ... second electrode 54 ... connection portion

Claims (9)

Comprising base material particles and a conductive layer disposed on the surface of the base material particles and containing nickel;
The nickel-containing conductive layer as a whole includes nickel, phosphorus, and tungsten,
The average content of nickel in the entire region of the conductive layer containing nickel is 90 wt% or more and 99.85 wt% or less,
In the region of 50% thickness from the inner surface to the outer side of the nickel-containing conductive layer, the average phosphorus content is 10% by weight or more,
The electroconductive particle whose average content of tungsten is 5 weight% or more in the area | region of thickness 10% toward the inner side from the outer surface of the conductive layer containing the said nickel. The conductive layer containing nickel has a conductive layer portion having an amorphous structure,
2. The conductive particle according to claim 1, wherein a ratio of a region of the thickness of the conductive layer portion of the amorphous structure occupying in a whole region of the conductive layer containing nickel is 30% or more. The electroconductive particle of Claim 1 or 2 whose average content of nickel in the whole area | region of the said electroconductive layer containing nickel is 90 to 95 weight%. The electroconductive particle of any one of Claims 1-3 whose average content of phosphorus in the whole area | region of the electroconductive layer containing the said nickel is 5 weight% or more and 10 weight% or less. The electroconductive particle of any one of Claims 1-4 whose average content of tungsten in the whole area | region of the electroconductive layer containing the said nickel is 0.5 weight% or more and 10 weight% or less. The electroconductive particle of any one of Claims 1-5 in which the electroconductive layer containing the said nickel has a processus | protrusion on an outer surface. The electroconductive particle of any one of Claims 1-6 further provided with the insulating substance arrange | positioned on the outer surface of the conductive layer containing the said nickel. And conductive particles according to any one of claims 1 to 7 and a binder resin, conductive material. A first connection target member;
A second connection target member;
A connecting portion connecting the first connection target member and the second connection target member;
A connection structure, wherein the connection portion is formed of the conductive particles according to any one of claims 1 to 7 , or is formed of a conductive material including the conductive particles and a binder resin.

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