KR101987509B1

KR101987509B1 - Conductive particles, conductive material and connection structure

Info

Publication number: KR101987509B1
Application number: KR1020147001314A
Authority: KR
Inventors: 게이조 니시오까; 마사히로 오오쯔까
Original assignee: 세키스이가가쿠 고교가부시키가이샤
Priority date: 2012-01-19
Filing date: 2013-01-15
Publication date: 2019-06-10
Also published as: TW201337957A; JP2018056138A; KR20140113628A; CN103748637B; WO2013108740A1; CN103748637A; JPWO2013108740A1; TWI601158B; JP6333552B2

Abstract

The present invention provides conductive particles capable of lowering the connection resistance between electrodes when used for connection between electrodes. The conductive particles 21 according to the present invention include base particles 2, a conductive layer 22 disposed on the surface of the base particles 2 and having a plurality of projections 22a on the outer surface thereof, And a plurality of inorganic particles (23) buried in the substrate (22). The inorganic particles 23 are disposed on the inner side of the projections 23a on the outer surface of the conductive layer 22. At least a part of the inorganic particles (23) of the plurality of inorganic particles (23) do not contact the surface of the base particle (2).

Description

TECHNICAL FIELD [0001] The present invention relates to conductive particles, conductive materials, and connection structures,

The present invention relates to a conductive particle which can be used, for example, for electrical connection between electrodes, and more particularly to a conductive particle which is disposed on the surface of base particles and has a plurality of projections on the outer surface Conductive particles. The present invention also relates to a conductive material and a connection structure using the conductive particles.

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

The anisotropic conductive material is used for connection between an IC chip and a flexible printed circuit board and for connecting a circuit board having an IC chip and an ITO electrode. For example, after the anisotropic conductive material is disposed between the electrodes of the IC chip and the electrodes of the circuit board, these electrodes can be electrically connected by heating and pressing.

As an example of the conductive particles, Patent Document 1 below discloses conductive particles comprising composite particles and a metal plating layer covering the composite particles. The composite particle has a plastic core and a non-conductive inorganic particle adsorbed by the chemical bond to the plastic core. In the conductive particles described in Patent Document 1, the metal plating layer has a surface on which protrusions are formed. Further, the non-conductive inorganic particles are harder than the metal plating layer.

The following Patent Document 2 discloses a conductive particle further comprising a second non-conductive inorganic particle adsorbed on a surface of a metal plating layer in the conductive particle described in Patent Document 1.

Japanese Patent Application Laid-Open No. 2011-29179 Japanese Patent Application Laid-Open No. 2011-29180

When the electrodes are connected using the conductive particles described in Patent Documents 1 and 2, the connection resistance between the electrodes can be reduced to some extent. However, even when the conductive particles described in Patent Documents 1 and 2 are used, the connection resistance between the electrodes may not be sufficiently lowered.

In addition, in order to lower the connection resistance between the electrodes, development of new conductive particles different from the conductive particles described in Patent Documents 1 and 2 has been desired.

An object of the present invention is to provide a conductive particle capable of lowering the connection resistance between electrodes when used for connection between electrodes, and a conductive material and a connection structure using the conductive particles.

According to a broad aspect of the present invention, there is provided a semiconductor device comprising: base particles; a conductive layer disposed on a surface of the base particle and having a plurality of projections on an outer surface;

), And the inorganic particles are arranged on the inner side of the projections on the outer surface of the conductive layer, and the inorganic particles of at least a part of the plurality of inorganic particles are not in contact with the surface of the base particles Conductive particles are provided.

In one specific aspect of the conductive particles according to the present invention, a plurality of the inorganic particles are disposed inside one of the projections on the outer surface of the conductive layer.

In another specific aspect of the conductive particle according to the present invention, at least 20% of the total number of the inorganic particles does not contact the surface of the base particle.

In another specific aspect of the conductive particles according to the present invention, the distance between the inorganic particles not in contact with the surface of the base particles and the base particles is 5 nm or more.

In another specific aspect of the conductive particles according to the present invention, a plurality of core materials embedded in the conductive layer are further provided.

In another specific aspect of the conductive particle according to the present invention, the core material is disposed on the inner side of the projection on the outer surface of the conductive layer, and one of the projections on the outer surface of the conductive layer and the core And the inorganic particles are disposed between the materials.

In another specific aspect of the conductive particles according to the present invention, the plurality of inorganic particles are in contact with the core material.

In another specific aspect of the conductive particles according to the present invention, the inorganic particles are adhered on the surface of the core material, and the core material and the inorganic particles form a composite.

In another specific aspect of the conductive particles according to the present invention, the core material is a metal particle.

In another specific aspect of the conductive particle according to the present invention, a plurality of the inorganic particles are localized so as to exist more on the outer surface side than the inner surface side of the conductive layer.

In another specific aspect of the conductive particles according to the present invention, an insulating material attached to the surface of the conductive layer is further provided.

The conductive material according to the present invention includes the above-described conductive particles and a binder resin.

The connecting structure according to the present invention includes a first connecting object member, a second connecting object member, and a connecting portion connecting the first and second connecting object members, wherein the connecting portion is formed by the above- Or formed of a conductive material containing the conductive particles and a binder resin.

The conductive particle according to the present invention comprises a base particle, a conductive layer disposed on the surface of the base particle and having a plurality of projections on the outer surface, and a plurality of inorganic particles embedded in the conductive layer, The inorganic particles are disposed on the inner side of the projections on the outer surface of the conductive layer and the inorganic particles of at least some of the plurality of inorganic particles do not contact the surface of the base particles, The connection resistance can be lowered.

1 is a cross-sectional view showing a conductive particle according to a first embodiment of the present invention.
2 is a cross-sectional view showing a conductive particle according to a second embodiment of the present invention.
3 is a cross-sectional view showing a conductive particle according to a third embodiment of the present invention.
Fig. 4 is a front sectional view schematically showing a connection structure using the conductive particles shown in Fig. 3; Fig.

Hereinafter, the details of the present invention will be described.

The conductive particle according to the present invention comprises a base particle, a conductive layer disposed on the surface of the base particle and having a plurality of projections on the outer surface, and a plurality of inorganic particles embedded in the conductive layer.

In the conductive particle according to the present invention, the conductive layer has a plurality of projections on the outer surface. In many cases, an oxide film is formed on the surface of an electrode connected by conductive particles. In many cases, an oxide film is formed on the outer surface of the conductive layer. The conductive layer has a plurality of protrusions on the outer surface thereof, and the conductive particles are disposed between the electrodes and then pressed, whereby the oxide film is effectively removed by the protrusions. Therefore, the electrodes and the conductive particles can be effectively brought into contact with each other, so that the connection resistance between the electrodes can be reduced. In addition, the protrusions can effectively remove the binder resin and the insulating material between the conductive particles and the electrode. Therefore, the reliability of conduction between the electrodes can be improved.

In the conductive particle according to the present invention, the inorganic particles are disposed on the inner surface of the projection on the outer surface of the conductive layer. Further, the inorganic particles of at least a part of the plurality of inorganic particles do not contact the surface of the base particle. At least some of the inorganic particles are spaced from the base particles. The inorganic particles not in contact with the surface of the base particles are disposed at positions closer to the outer surface of the conductive layer than the inorganic particles in contact with the surface of the base particles.

By the use of the above-described constitution of the conductive particles according to the present invention, particularly, by the presence of the inorganic particles which are not in contact with the surface of the base particles due to the arrangement of the inorganic particles inside the projections, The hardness of the protruding portion in the conductive particles derived from the inorganic particles is effectively stiffened and the connection resistance between the electrodes connected by the conductive particles can be reduced. For example, since the conductive layer is likely to be strongly pressed against the electrode due to the rigid inorganic particles at the time of pressing between the electrodes, the connection resistance is lowered. It is also possible to form an appropriate indentation on the electrode when the electrodes are connected by compressing the conductive particles. The indentations formed on the electrodes are concave portions of the electrodes formed by pressing the electrodes with the conductive particles. Further, when a conductive material (anisotropic conductive material or the like) in which the conductive particles are dispersed in the binder resin is used for pressing between the electrodes, the binder resin between the conductive layer and the electrodes can be effectively removed. The connection resistance between the electrodes can be reduced even by effectively excluding the binder resin.

Further, in the present invention, the inorganic particles not in contact with the surface of the base particle may be close to the outer surface side of the conductive layer. When the inorganic particles are close to the outer surface side of the conductive layer, the hardness of the protruding portion in the conductive particle becomes more effective, and the connection resistance between the electrodes can be effectively lowered. The inorganic particles not in contact with the surface of the base particles are not chemically bonded to the base particles. It is preferable that the inorganic particles in contact with the surface of the base particles are not chemically bonded to the base particles. The inorganic particles do not chemically bond to the base particles so that the functional groups for chemically bonding the inorganic particles and the base particles to the surface of the inorganic particles or the surface of the base particles may not be introduced. Therefore, it is not necessary to prepare a new substance for introducing a functional group, and the step of introducing a functional group is not required, and therefore, the production efficiency of the conductive particles can be increased. It is preferable that the conductive particles include inorganic particles that are not adsorbed to the base particles by chemical bonding. It is preferable that the inorganic particles are not adsorbed to the base particles by chemical bonding.

The conductive particles according to the present invention may further include a plurality of core materials embedded in the conductive layer. However, the conductive particles according to the present invention may not necessarily include a core material. It is easy to form projections on the outer surface of the conductive layer by the core material and to make the inorganic particles close to the outer surface side of the conductive layer. When the inorganic particles are close to the outer surface side of the conductive layer, the hardness of the protruding portion in the conductive particles effectively increases, and the connection resistance between the electrodes can be effectively lowered.

It is preferable that a plurality of the inorganic particles are arranged on the inside of one of the projections on the outer surface of the conductive layer, and it is preferable that five or more inorganic particles are arranged. The core material is disposed inside the protrusion on the outer surface of the conductive layer and the inorganic particles are disposed between one of the protrusions on the outer surface of the conductive layer and the core material disposed on the inner side of the protrusion More preferably a plurality of the inorganic particles are disposed, and it is preferable that at least 5 or more of the inorganic particles are disposed. In these cases, the hardness at the protruding portions in the conductive particles is effectively increased. Therefore, at the time of pressing between the electrodes, the conductive layer is strongly pressed by the electrodes by the inorganic particles disposed inside the projections, so that the connection resistance between the electrodes can be effectively lowered.

It is preferable that a plurality of the inorganic particles are localized so as to exist on the outer surface side more than the inner surface side of the conductive layer. In this case, since the conductive particles are strongly pressed against the electrodes by the inorganic particles disposed inside the projections and near the outer surface of the conductive layer at the time of pressing between the electrodes, the connection resistance between the electrodes can be further reduced.

It is preferable that the conductive layer is disposed between the surface of at least a part of the inorganic particles and the surface of the base particle. In addition, it is preferable that the conductive layer or the core material be disposed between the surface of at least a part of the inorganic particles and the surface of the base particle, and the core material is preferably disposed. It is preferable that the conductive layer or the core material be disposed between the surface of the inorganic particle and the surface of the base particle in an amount of 20% or more (preferably 50% or more) of the total number of the inorganic particles, It is preferable to arrange them. It is preferable that at least 20% (preferably at least 50%) of the inorganic particles in the total number of the inorganic particles are not in contact with the base particles, and the base particles are preferably spaced apart from the base particles. In these cases, since the conductive layer originates from the inorganic particles at the time of pressing between the electrodes, the electrodes are pressed more strongly by the electrodes, so that the connection resistance between the electrodes can be further reduced.

The inorganic particles are preferably harder than the conductive layer. In this case, since the conductive layer originates from the inorganic particles at the time of pressing between the electrodes, the electrodes are pressed more strongly by the electrodes, so that the connection resistance between the electrodes can be further reduced.

The distance X between the inorganic particles not in contact with the surface of the base particles and the base particles is preferably 5 nm or more, more preferably 5 nm or more, further preferably 10 nm or more, preferably 1 m or less, More preferably not more than 0.3 mu m. When there is only one inorganic particle not in contact with the surface of the base particle, the distance X represents the shortest distance between one inorganic particle and the base particle. When there are a plurality of inorganic particles not in contact with the surface of the base particle, the distance X is obtained by measuring the shortest distance between one inorganic particle and the base particle and calculating an average value of the shortest distance . When there are 10 or more inorganic particles not in contact with the surface of the base particles, the distance X is obtained by measuring the shortest distance between all the inorganic particles and the base particles and calculating the average of all the shortest distances However, it may be obtained by measuring 10 shortest distances between 10 inorganic particles and the base particles, and calculating the average of the shortest distances of 10 points. The distance X may be 9/10 or less, 4/5 or less, 1/2 or less, or 1/3 or less of the thickness of the conductive layer.

From the viewpoint that the electrode and the oxide film on the surface of the conductive particle are more effectively excluded and the reliability of the conduction between the electrodes is further enhanced, the inorganic particles having the shortest distance between the inorganic particles and the base particles of 100% Is preferably 50% or more, more preferably 80% or more, and 100% or less. In the whole of the inorganic particles, the shortest distance between the inorganic particles and the base particles may be 5 nm or more. The ratio of the number of the inorganic particles having the shortest distance of 10 nm or more among the inorganic particles and the base particles in the total number 100% of the inorganic particles is preferably 50% or more, more preferably 80% or more and 100% to be. In the whole of the inorganic particles, the shortest distance between the inorganic particles and the base particles may be 10 nm or more.

The shortest distance between the inorganic particle and the base particle can be accurately measured by photographing a cross section of a plurality of portions of the conductive particle to obtain an image, creating a stereoscopic image from the obtained image, and using the obtained stereoscopic image. The section can be photographed using a focused ion beam-scanning electron microscope (FIBSEM) or the like. For example, a thin film slice of conductive particles is produced using a focused ion beam, and a cross section is observed with a scanning electron microscope. By repeating the operation several hundred times and performing image analysis, a three-dimensional image of the particle is obtained.

With respect to the details of the measurement method, the obtained conductive particles are cut and observed by a cross section, whereby the distance between the surface of the base particles and the plurality of inorganic particles can be measured. The distance between the surface of the base particle and the surface of the core material can be measured by photographing a plurality of cross sections of the conductive particle to obtain an image and using the obtained stereoscopic image to create a stereoscopic image. The cross-section is photographed using Helios NanoLab. 650 or the like, which is a condensed ion beam-scanning electron microscope (FIBSEM) device manufactured by Nippon FEI. A thin-film slice of conductive particles is produced using a focused ion beam, and a cross-section is observed with a scanning electron microscope. By repeating the operation 200 times and performing image analysis, a three-dimensional image of the particles is obtained. The distance between the surface of the base particle and the surface of the inorganic particle is obtained from the stereoscopic image and the distance between the surface of the base particle and the surface of the inorganic particle in the total number of 100% Percentage (%) can be obtained.

Hereinafter, the details of the conductive particles, the conductive material, and the connection structure will be described.

(Conductive particles)

1 is a cross-sectional view showing a conductive particle according to a first embodiment of the present invention. 2 is a cross-sectional view showing a conductive particle according to a second embodiment of the present invention. 3 is a cross-sectional view showing a conductive particle according to a third embodiment of the present invention.

First, the conductive particles 1 shown in Fig. 3 will be described. The conductive particles 1 shown in Fig. 3 are provided with base particles 2, a conductive layer 3, a plurality of core materials 4, a plurality of inorganic particles 5 and an insulating material 6 do. The conductive layer 3 is disposed on the surface of the base particle 2. The conductive layer 3 has a plurality of projections 3a on its outer surface. A plurality of core materials 4 are arranged on the surface of the base material particles 2 and are embedded in the conductive layer 3. The core material 4 is disposed inside the projection 3a. A plurality of the inorganic particles 5 are arranged on the surface of the base particle 2 and are embedded in the conductive layer 3. The insulating material 6 is disposed on the surface of the conductive layer 3.

The insulating material 6 is insulating particles. The insulating material 6 is formed by a material having an insulating property. The conductive particles may not necessarily be provided with an insulating material. Further, the conductive particles may be provided with an insulating layer covering the outer surface of the conductive layer instead of the insulating particles as an insulating material.

In the conductive particle 1, a plurality of inorganic particles 5 are disposed inside one projection 3a on the outer surface of the conductive layer 3. [ A plurality of inorganic particles 5 are disposed between one protrusion 3a on the outer surface of the conductive layer 3 and the core material 4 disposed on the inside of the protrusion 3a. The conductive layer 3 or the core material 4 is disposed between the surface of at least a part of the inorganic particles 5 and the surface of the base particle 2. At least some of the inorganic particles 5 are not in contact with the base particles 2, but are distanced from the base particles 2. Further, the plurality of inorganic particles 5 are in contact with the core material 4. A plurality of inorganic particles (5) are attached to the core material (4). The plurality of inorganic particles 5 are not chemically bonded to the base particles 2 and are not adsorbed by chemical bonds. The inorganic particles (5) not in contact with the base particles (2) are not chemically bonded to the base particles (2). The inorganic particles (5) are harder than the conductive layer (3). The Mohs hardness of the inorganic particles 5 is higher than the Mohs hardness of the conductive layer 3.

In the conductive particles (1), at least a part of the inorganic particles (5) are in contact with the base particles (2). The conductive particles (1) include the inorganic particles (5) in contact with the base particles (2). The inorganic particles (5) in contact with the base particles (2) are not chemically bonded to the base particles (2). The conductive particles (1) also include the inorganic particles (5) which are not in contact with the base particles (2). In the conductive particles 1, the base particles 2 and the core material 4 are not in contact with each other. The base particles 2 and the core material 4 may be in contact with each other.

The conductive particles 11 shown in Fig. 2 include base particles 2, a conductive layer 12, a plurality of core materials 13, a plurality of inorganic particles 14 and insulating particles 6 . The conductive layer 12 is disposed on the surface of the base particle 2. The conductive layer 12 has a plurality of projections 12a on its outer surface. A plurality of core materials (13) are embedded in the conductive layer (12). The core material 13 is disposed inside the projection 12a. A plurality of inorganic particles (14) are embedded in the conductive layer (12). The insulating particles 6 are disposed on the surface of the conductive layer 12.

In the conductive particles 11, the core material 13 and the inorganic particles 14 are not in contact with each other. Thus, the core material 13 and the inorganic particles 14 may not be in contact with each other.

In the conductive particles 11, a plurality of inorganic particles 14 are disposed inside one projection 12a on the outer surface of the conductive layer 12. [ The inorganic particles 14 are not in contact with the base particles 2. In the conductive particles 11, a plurality of inorganic particles 14 are localized so as to exist more on the outer surface side than the inner surface side of the conductive layer 12. As a result, the hardness of the protrusions 12a in the conductive particles 11 is effectively increased by the inorganic particles 14. Therefore, by using the conductive particles 11, the connection resistance between the electrodes is further lowered.

In the conductive particles 11, a plurality of the inorganic particles 14 are present in a region of ½ of the thickness of the outer surface of the conductive layer 12 from the area of ½ of the thickness on the inner surface side of the conductive layer 12. Even in the conductive particles 21 described later, the plurality of inorganic particles 23 are formed in a region 1/2 of the thickness of the outer surface of the conductive layer 22, exist. For example, in 100% of the total number of the inorganic particles 14, 23, the inorganic particles 14, 23 exist in an area of 1/2 of the thickness on the outer surface side of the conductive layers 12, 22 by more than 50% , Preferably 60% or more, and more preferably 70% or more. It is also preferable that the plurality of inorganic particles 14 and 23 are present in a region having a thickness of 1/2 of the inner surface side of the conductive layers 12 and 22 or a region having a thickness of 1/2 of the outer surface side of the conductive layers 12 and 22 It is judged based on the center point of the inorganic particles 14 and 23 as a reference.

In the conductive particles 11, most of the inorganic particles 14 are not in contact with the core material 13 and are not attached. Thus, the inorganic particles may not necessarily contact the core material.

The conductive particles 21 shown in Fig. 1 include base particles 2, a conductive layer 22, a plurality of inorganic particles 23, and insulating particles 6. The conductive layer 22 is disposed on the surface of the base particle 2. The conductive layer 22 has a plurality of projections 22a on its outer surface. The plurality of inorganic particles 23 are embedded in the conductive layer 22. The insulating particles 6 are disposed on the surface of the conductive layer 22. The conductive particles 21 do not have a core material. As described above, the conductive particles may not necessarily be provided with the core material.

In the conductive particles 21, a plurality of inorganic particles 23 are arranged inside one projection 22a on the outer surface of the conductive layer 22. [ The inorganic particles 23 are not in contact with the base particles 2. In the conductive particles 21, as in the case of the conductive particles 11, a plurality of inorganic particles 23 are localized so as to exist more on the outer surface side than on the inner surface side of the conductive layer 22. As a result, the hardness of the protruding portions in the conductive particles 21 is effectively increased by the inorganic particles 23. Therefore, by using the conductive particles 21, the connection resistance between the electrodes is further lowered.

Among the conductive particles (1, 11, 21), the conductive particles (21) are preferable. The production of the conductive particles 21 is relatively easy.

[Substrate Particle]

Examples of the base particles include resin particles, inorganic particles other than metals, organic-inorganic hybrid particles and metal particles. The base particles are preferably base particles excluding metal particles, more preferably resin particles, inorganic particles other than metal, or organic-inorganic hybrid particles.

The base particles are preferably resin particles formed by a resin. When the electrodes are connected using the conductive particles, the conductive particles are disposed between the electrodes and then compressed to compress the conductive particles. When the base particles are resin particles, the conductive particles are liable to be deformed at the time of pressing so that the contact area between the conductive particles and the electrodes becomes large. This improves the reliability of conduction between the electrodes.

As the resin for forming the resin particles, various organic materials are preferably used. Examples of the resin for forming the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polypropylene, polyisobutylene, and polybutadiene; Acrylic resins such as polymethyl methacrylate and polymethyl acrylate; Polyalkylene 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 , Various unsaturated polyester resins, saturated polyester resins, polysulfone, polyphenylene oxide, polyacetal, polyimide, polyamideimide, polyether ether ketone, polyether sulfone, and ethylenic unsaturated groups are referred to as 1 And polymers obtained by polymerizing two or more species. It is possible to design and synthesize resin particles having physical properties at the time of compression appropriate for the conductive material and to control the hardness of the base particles to a desired range with ease. Therefore, the resin for forming the resin particles preferably contains an ethylenic unsaturated group It is preferably a polymer obtained by polymerizing one or more polymerizable monomers having a plurality of polymerizable monomers.

When the resin particle is obtained by polymerizing a monomer having an ethylenic unsaturated group, examples of the monomer having an ethylenic unsaturated group include a monomer which is incompatible with the monomer and a monomer which is crosslinkable.

Examples of the non-crosslinkable monomer include styrene-based monomers such as styrene and? -Methylstyrene; Carboxyl group-containing monomers such as (meth) acrylic acid, maleic acid, and maleic anhydride; (Meth) acrylate, ethyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl Alkyl (meth) acrylates such as acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate and isobornyl (meth) acrylate; (Meth) acrylates such as 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate and glycidyl (meth) acrylate; Nitrile-containing monomers such as (meth) acrylonitrile; Vinyl ethers such as methyl vinyl ether, ethyl vinyl ether and propyl vinyl ether; Acid vinyl esters such as vinyl acetate, vinyl butyrate, vinyl laurate and vinyl stearate; 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.

Examples of the crosslinkable monomer include tetramethylolmethane tetra (meth) acrylate, tetramethylol methane tri (meth) acrylate, tetramethylol methane di (meth) acrylate, trimethylolpropane tri (meth) (Meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri (meth) acrylate, glycerol di (meth) acrylate, (poly) ethylene glycol di Polyfunctional (meth) acrylates such as (poly) propylene glycol di (meth) acrylate, (poly) tetramethylene di (meth) acrylate and 1,4-butanediol di (meth) acrylate; (Meth) acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, trimethylolpropane trimethoxysilane, triallyl trimellitate, divinyl benzene, diallyl phthalate, diallyl acrylamide, diallyl ether, , Silane-containing monomers such as vinyltrimethoxysilane, and the like.

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

When the base particles are inorganic particles other than metal particles or organic-inorganic hybrid particles, examples of inorganic substances for forming the base particles include silica and carbon black. The particles formed by the silica are not particularly limited. For example, particles obtained by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups to form cross-linked polymer particles, followed by baking if necessary, . Examples of the organic-inorganic hybrid particles include organic-inorganic hybrid particles formed of a crosslinked alkoxysilyl polymer and an acrylic resin.

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

The particle size of the base particles is preferably 0.1 mu m or more, more preferably 0.5 mu m or more, still more preferably 1 mu m or more, still more preferably 1.5 mu m or more, particularly preferably 2 mu m or more, More preferably not more than 500 mu m, still more preferably not more than 300 mu m, further preferably not more than 50 mu m, further preferably not more than 30 mu m, particularly preferably not more than 5 mu m, 3 탆 or less. When the particle diameter of the base particles is not lower than the lower limit described above, the contact area between the conductive particles and the electrode becomes larger, so that the reliability of the connection between the electrodes becomes further higher, and the connection resistance between the electrodes connected through the conductive particles becomes further lower. Further, when the conductive layer is formed on the surface of the base particles by electroless plating, it is difficult to coagulate, and it becomes difficult to form the cohered conductive particles. When the particle diameter is less than the upper limit, the conductive particles are easily compressed sufficiently, the connection resistance between the electrodes is further lowered, and the gap between the electrodes is reduced. The particle diameter of the base particles indicates a diameter when the base particles are spherical and the maximum diameter when base particles are not spherical.

Particularly preferably, the particle size of the base particles is 0.1 탆 or more and 5 탆 or less. If the particle diameter of the base particles is within the range of 0.1 to 5 占 퐉, the interval between the electrodes becomes small, and even if the thickness of the conductive layer is increased, small conductive particles can be obtained. From the viewpoint of obtaining even smaller conductive particles even when the distance between the electrodes is further reduced or the thickness of the conductive layer is increased, the particle size of the base particles is preferably 0.5 占 퐉 or more, more preferably 2 占 퐉 or more Or less.

[Conductive layer]

The metal for forming the conductive layer is not particularly limited. In the case where the conductive particles are metal particles whose entire surface is a conductive layer, the metal for forming the metal particles is not particularly limited. Examples of the metal include gold, silver, copper, palladium, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, thallium, germanium, cadmium, , Molybdenum, and alloys thereof. Examples of the metal include indium tin oxide (ITO) and solder. Among them, an alloy containing tin, nickel, palladium, copper or gold is preferable, and nickel or palladium is more preferable because connection resistance between the electrodes can be further reduced. The metal constituting the conductive layer preferably includes nickel. The conductive layer preferably includes at least one selected from the group consisting of nickel, tungsten, molybdenum, palladium, phosphorus, and boron, and more preferably includes nickel, phosphorus, or boron. The material constituting the conductive layer may be an alloy including phosphorus and boron. In the conductive layer, nickel, tungsten or molybdenum may be alloyed.

When the conductive layer contains phosphorus or boron, the total content of phosphorus and boron in 100 wt% of the conductive layer is preferably 4 wt% or less. When the total content of phosphorus and boron is not more than the upper limit, the content of metal such as nickel becomes relatively large, so that the connection resistance between the electrodes is further lowered. The total content of phosphorus and boron in 100 wt% of the conductive layer is preferably 0.1 wt% or more, and more preferably 0.5 wt% or more.

The conductive layer may be formed of one layer or may be formed of a plurality of layers. That is, the conductive layer may be a single layer or may have a laminated structure of two or more layers. When the conductive layer is formed of a plurality of layers, it is preferable that the outermost layer is a gold layer, a nickel layer, a palladium layer, a copper layer, or an alloy layer containing tin and silver, more preferably a gold layer or a palladium layer , And gold layer are particularly preferable. When the outermost layer is the preferable conductive layer, the connection resistance between the electrodes is further lowered. Further, when the outermost layer is a gold layer, corrosion resistance is further increased.

The method of forming the conductive layer on the surface of the base particles is not particularly limited. Examples of the method of forming the conductive layer include a method of electroless plating, a method of electroplating, a method of physical vapor deposition, and a method of coating a surface of base particles with a paste containing metal powder or metal powder and a binder And the like. Among them, the electroless plating method is preferable because the formation of the conductive layer is simple. Examples of the physical deposition method include vacuum deposition, ion plating and ion sputtering.

The average particle diameter of the conductive particles is preferably 0.11 占 퐉 or more, more preferably 0.5 占 퐉 or more, further preferably 0.51 占 퐉 or more, particularly preferably 1 占 퐉 or more, preferably 100 占 퐉 or less, 20 mu m or less, more preferably 5.6 mu m or less, particularly preferably 3.6 mu m or less. When the average particle diameter of the conductive particles is not less than the lower limit and not more than the upper limit described above, the contact area between the conductive particles and the electrode becomes sufficiently large when the electrodes are connected using the conductive particles. When the conductive particles are formed, . Further, the distance between the electrodes connected via the conductive particles is not excessively large, and the conductive layer is difficult to peel off from the surface of the base particles.

The "average particle diameter" of the conductive particles indicates the number average particle diameter. The average particle diameter of the conductive particles can be obtained by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating an average value.

The thickness of the conductive layer is preferably 0.005 탆 or more, more preferably 0.01 탆 or more, preferably 1 탆 or less, and more preferably 0.3 탆 or less. When the thickness of the conductive layer is not less than the lower limit and not more than the upper limit, sufficient conductivity is obtained and the conductive particles are not too hard, and the conductive particles are sufficiently deformed when the electrodes are connected.

In the case where the conductive layer is formed of a plurality of layers, the thickness of the outermost conductive layer is preferably 0.001 mu m or more, more preferably 0.01 mu m or more, particularly when the outermost layer is a gold layer, Or more, preferably 0.5 탆 or less, and more preferably 0.1 탆 or less. If the thickness of the conductive layer of the outermost layer is not less than the lower limit and not more than the upper limit, the covering by the conductive layer of the outermost layer can be uniformed, the corrosion resistance can be sufficiently increased, have.

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

The number of protrusions on the outer surface of the conductive layer per one conductive particle is preferably 3 or more, more preferably 5 or more. The upper limit of the number of the projections is not particularly limited. The upper limit of the number of protrusions can be appropriately selected in consideration of the average particle diameter of the conductive particles and the like.

The average height of the plurality of projections is preferably 0.001 탆 or more, more preferably 0.05 탆 or more, preferably 0.9 탆 or less, and more preferably 0.2 탆 or less. When the average height of the projections is not less than the lower limit and not more than the upper limit, the connection resistance between the electrodes can be effectively lowered.

[Core material]

Since the core material is embedded in the conductive layer, it is easy for the conductive layer to have a plurality of projections on the outer surface.

Examples of the method for forming the projections include a method in which a core material is attached to the surface of base particles and then a conductive layer is formed by electroless plating and a method in which a conductive layer is formed on the surface of base particles by electroless plating, And a method of forming a conductive layer by electroless plating.

Examples of the method for disposing the core material on the surface of the base particles include a method of adding a conductive material to be a core material in the dispersion of the base particles to form a core material on the surface of the base particles or metal particles, A method in which a core material is added to a container containing base particles or metal particles and a core material is adhered to the surface of base particles or metal particles by mechanical action by rotation of the container or the like And the like. Among them, a method of integrating and attaching a core material to the surface of base particles or metal particles in the dispersion is preferable because it is easy to control the amount of the core material to be adhered.

Examples of the material constituting the core material include a conductive material and a non-conductive material. Examples of the conductive material include metals, oxides of metals, conductive nonmetals such as graphite, and conductive polymers. Examples of the conductive polymer include polyacetylene. Examples of the non-conductive material include silica, alumina, and zirconia. Among them, a metal is preferable because the conductivity can be increased and the connection resistance can be effectively lowered. The core material is preferably a metal particle.

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

The shape of the core material is not particularly limited. The core material preferably has a lump shape. Examples of the core material include a lump of particles, an agglomerated mass agglomerated by a plurality of minute particles, and a lump of an irregular shape. Preferably, the core material is particulate and the core material is a core particle.

The average diameter (average particle diameter) of the core material is preferably 0.001 탆 or more, more preferably 0.05 탆 or more, preferably 0.9 탆 or less, and more preferably 0.2 탆 or less. If the average diameter of the core material is not less than the lower limit and not more than the upper limit, the connection resistance between the electrodes can be effectively lowered.

The "average diameter (average particle diameter)" of the core material represents a number average diameter (number average particle diameter). The average diameter of the core material can be obtained by observing 50 pieces of any core material with an electron microscope or an optical microscope and calculating an average value.

[Inorganic Particles]

It is preferable that the inorganic particles embedded in the conductive layer are harder than the conductive layer. In this case, the hardness of the protruding portion derived from the inorganic particles in the conductive particles becomes much harder, and the connection resistance between the electrodes connected by the conductive particles can be lowered.

Examples of the inorganic particles include silica (silicon dioxide, Mohs hardness of 6 to 7), zirconia (Mohs hardness of 8 to 9), alumina (Mohs hardness of 9), tungsten carbide of Mohs hardness of 9 and diamond . The inorganic particles are preferably silica, zirconia, alumina, tungsten carbide or diamond, and silica, zirconia, alumina or diamond is also preferable. The Mohs hardness of the inorganic particles is preferably 5 or more, and more preferably 6 or more. The Mohs hardness of the inorganic particles is preferably larger than the Mohs hardness of the conductive layer. The absolute value of the difference between the Mohs hardness of the inorganic particles and the Mohs hardness of the conductive layer is preferably 0.1 or more, more preferably 0.2 or more, further preferably 0.5 or more, particularly preferably 1 or more. When the conductive layer is formed by a plurality of layers, the inorganic particles are harder than all the metals constituting the plurality of layers, and the effect of reducing the connection resistance is more effectively exhibited.

The plurality of inorganic particles may be in contact with the core material. The inorganic particles may be attached to the surface of the core material. The core material and the inorganic particles may be arranged on the surface of the base particles by using the core material having the inorganic particles adhered to the surface thereof.

The average particle diameter of the inorganic particles is preferably 0.0001 탆 or more, more preferably 0.005 탆 or more, preferably 0.5 탆 or less, and more preferably 0.1 탆 or less. When the average particle diameter of the inorganic particles is not less than the lower limit and not more than the upper limit, the connection resistance between the electrodes can be effectively lowered.

The "average particle diameter" of the inorganic particles indicates the number average particle diameter. The average particle size of the inorganic particles can be obtained by observing 50 arbitrary inorganic particles with an electron microscope or an optical microscope and calculating an average value.

In the conductive particle 1 shown in Fig. 3, a plurality of the inorganic particles 5 are in contact with the core material 4. Fig. The inorganic particles 5 are selectively arranged on the inside of the projections 3a on the outer surface of the conductive layer 3. It is preferable that a plurality of the inorganic particles are localized so as to exist in a larger amount on the inner side of the projections on the outer surface of the conductive layer than on the inner side of the projected outer surface portion of the conductive layer. Examples of the method of selectively placing the inorganic particles on the inside of the projections include a method of attaching the inorganic particles to the core material. Specifically, after attaching the inorganic particles to the surface of the core material, A method of disposing a substance on the surface of the base particle and then covering the base material and the core material with the inorganic particle attached thereto by a conductive layer. Other methods may be used.

It is preferable that a plurality of the inorganic particles 14 and 23 are localized so as to exist more on the outer surface side than the inner surface side of the conductive layers 12 and 22 like the conductive particles 11 and 21 shown in Figs. desirable. As a method for localizing the inorganic particles in this manner, there are a method of forming the conductive layer by a plurality of layers and containing a larger amount of inorganic particles in the conductive layer on the outer side than the inner conductive layer, and a method of forming the conductive layer by electroless plating And a method of including a large amount of inorganic particles in the electroless plating bath at a later stage than the initial stage of the electroless plating. Other methods may be used.

It is preferable that the inorganic particles are adhered on the surface of the core material in order to effectively increase the hardness at the protruding portions in the conductive particles and further lower the connection resistance between the electrodes, As shown in Fig. The composite having the inorganic particles adhered on the surface of the core material is prepared and the composite is embedded in the conductive layer at the time of forming the conductive layer to obtain the conductive particles having the composite. It is easy to embed the core material and the inorganic particles in the conductive layer so that at least a part of the inorganic particles of the plurality of inorganic particles do not come into contact with the surface of the base particles.

The inorganic particles may be attached to the core material by chemical bonding, or may be mechanically or physically attached.

The average diameter (average particle diameter) of the composite is preferably 0.0012 μm or more, more preferably 0.0502 μm or more, preferably 1.9 μm or less, and more preferably 1.2 μm or less. When the average diameter of the composite is not less than the lower limit and not more than the upper limit, the connection resistance between the electrodes can be effectively lowered.

The "average diameter (average particle diameter)" of the composite indicates the number average diameter (number average particle diameter). The average diameter of the composite can be obtained by observing 50 pieces of any core material with an electron microscope or an optical microscope and calculating an average value.

[Insulating material]

The conductive particles according to the present invention preferably include an insulating material disposed on the surface of the conductive layer. In this case, if conductive particles are used for connection between the electrodes, a short circuit between adjacent electrodes can be prevented. Specifically, since the insulating material exists between a plurality of electrodes when a plurality of conductive particles are brought into contact with each other, it is possible to prevent a short circuit between adjacent electrodes in the lateral direction as well as between the upper and lower electrodes. Further, by pressurizing the conductive particles with two electrodes at the time of connection between the electrodes, the insulating material between the conductive layer of the conductive particles and the electrode can be easily excluded. Since the conductive particles have a plurality of protrusions on the outer surface of the conductive layer, the insulating material between the conductive layer of the conductive particles and the electrode can be easily removed.

It is preferable that the insulating material is an insulating particle since the insulating material can be easily removed at the time of pressing between the electrodes.

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

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 a vinyl polymer and a vinyl copolymer. Examples of the thermosetting resin include an epoxy resin, a phenol resin, and a melamine resin. Examples of the water-soluble resin include polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinylpyrrolidone, polyethylene oxide, methylcellulose and the like. Among them, a water-soluble resin is preferable, and polyvinyl alcohol is more preferable.

Examples of the method of disposing the insulating material on the surface of the conductive layer include a chemical method and a physical or mechanical method. Examples of the chemical method include an interfacial polymerization method, a suspension polymerization method in the presence of particles, and an emulsion polymerization method. Examples of the physical or mechanical method include spray drying, hybridization, electrostatic deposition, spraying, dipping and vacuum deposition. Among them, a method of disposing the insulating material on the surface of the conductive layer through chemical bonding is preferable in that the insulating material is difficult to desorb.

The average diameter (the average particle diameter of the insulating particles) of the insulating material can be appropriately selected in accordance with the particle diameter of the conductive particles and the use of the conductive particles. The average diameter (average particle diameter of insulating particles) of the insulating material is preferably 0.005 탆 or more, more preferably 0.01 탆 or more, preferably 1 탆 or less, and more preferably 0.5 탆 or less. When the average diameter (average particle diameter) of the insulating material is not less than the lower limit described above, when the conductive particles are dispersed in the binder resin, the conductive layers in the plurality of conductive particles are hardly brought into contact with each other. When the average diameter (average particle diameter) of the insulating material is not more than the upper limit, there is no need to excessively elevate the pressure in order to exclude the insulating material between the electrode and the conductive particles at the time of connecting the electrodes, and it is unnecessary to heat at a high temperature.

The "average diameter (average particle diameter)" of the insulating material represents a number average diameter (number average particle diameter). The average diameter of the insulating material can be obtained by using a particle size distribution measuring device or the like.

(Conductive material)

The conductive material according to the present invention includes the above-described conductive particles and a binder resin. The conductive particles are preferably dispersed in the binder resin and used as a conductive material. The conductive material is preferably an anisotropic conductive material.

The binder resin is not particularly limited. An insulating resin known as the binder resin is used.

The conductive material may contain, in addition to the conductive particles and the binder resin, a filler, an extender, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, Flame retardant, and the like.

The method of dispersing the conductive particles in the binder resin may be any conventionally known dispersion method and is not particularly limited. Examples of the method for dispersing the conductive particles in the binder resin include a method in which the conductive particles are added to the binder resin and then kneaded and dispersed with a planetary mixer or the like; a method in which the conductive particles are dispersed in water or an organic solvent And then the mixture is added to the binder resin and kneaded and dispersed by a planetary mixer or the like, and a method in which the binder resin is diluted with water or an organic solvent, and then the conductive particles are added, A method of mixing and kneading with a mixer or the like, and the like.

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

The content of the binder resin in 100 wt% of the conductive material is preferably 10 wt% or more, more preferably 30 wt% or more, still more preferably 50 wt% or more, particularly preferably 70 wt% Is 99.99% by weight or less, and more preferably 99.9% by weight or less. When the content of the binder resin is not less than the lower limit and not more than the upper limit, the conductive particles are efficiently arranged between the electrodes, and the connection reliability of the connection member connected by the conductive material is further enhanced.

The content of the conductive particles in 100 wt% of the conductive material is preferably at least 0.01 wt%, more preferably at least 0.1 wt%, preferably at most 40 wt%, more preferably at most 20 wt% By weight is not more than 10% by weight. When the content of the conductive particles is not less than the lower limit and not more than the upper limit, the reliability of the conduction between the electrodes is further enhanced.

(Connection structure)

The connection structure can be obtained by using the conductive particles of the present invention or by connecting the connection target members using a conductive material containing the conductive particles and the binder resin.

The connection structure includes a connection portion for electrically connecting the first connection target member, the second connection target member, and the first and second connection target members, and the connection portion is formed by the conductive particles of the present invention Or a connection structure formed by a conductive material (anisotropic conductive material or the like) including the conductive particles and a binder resin. In the case where conductive particles are used, the connection itself is a conductive particle. That is, the first and second connection target members are connected by the conductive particles.

4 is a front sectional view schematically showing a connection structure using conductive particles according to an embodiment of the present invention.

The connection structure 51 shown in Fig. 4 has a connection structure in which the first connection target member 52, the second connection target member 53, and the connecting portion connecting the first and second connection target members 52 and 53 54). The connection portion 54 is formed by curing a conductive material containing the conductive particles 1. [ In Fig. 4, the conductive particles 1 are shown schematically for convenience of illustration. Instead of the conductive particles 1, the conductive particles 11 and 21 may be used.

The first connection target member 52 has a plurality of electrodes 52b on the upper surface 52a (surface). The second connection target member 53 has a plurality of electrodes 53b on the lower surface 53a (surface). The electrode 52b and the electrode 53b 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 a method of manufacturing the connection structure, there is a method of arranging the conductive material between the first connection target member and the second connection target member to obtain a laminate, and then heating and pressing the laminate.

The pressure of the pressurization is about 9.8 x 10 ⁴ to 4.9 x 10 ⁶ Pa. The heating temperature is about 120 to 220 占 폚.

Specifically, examples of the member to be connected include electronic parts such as semiconductor chips, condensers and diodes, and electronic parts which are circuit boards such as printed boards, flexible printed 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 electronic components.

Examples of the electrode provided on the member to be connected include a metal electrode such as a gold electrode, a nickel electrode, a tin electrode, an aluminum electrode, a copper electrode, a molybdenum electrode, and a tungsten electrode. When the connection target member is a flexible printed board, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, or a copper electrode. When the connection target member is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode, or a tungsten electrode. When the electrode is an aluminum electrode, it may be an electrode formed only of aluminum, or an electrode in which an aluminum layer is laminated on the surface of the metal oxide layer. Examples of the material of 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. It is preferable that the electrode is an ITO electrode, an IZO electrode, an AZO electrode, a GZO electrode, or a ZnO electrode. These electrode surfaces are relatively rigid. In the conductive particle according to the present invention, since the hardness of the protruding portion is relatively hard, the conductive layer and the relatively hard electrode can be effectively brought into contact with each other, and the connection resistance between the electrodes can be effectively lowered.

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. The present invention is not limited to the following examples.

(Example 1)

(1) palladium deposition process

Divinylbenzene copolymer resin particles (Micropearl SP-203, manufactured by Sekisui Chemical Co., Ltd.) having a particle size of 3.0 mu m were prepared.

10 parts by weight of the resin particles were dispersed in 100 parts by weight of an alkali solution containing 5% by weight of a palladium catalyst solution using an ultrasonic disperser, and the solution was filtered to take out the resin particles. Subsequently, the resin particles were added to 100 parts by weight of a 1 wt% solution of dimethylamine borane to activate the surface of the resin particles. The surface-activated resin particles were sufficiently washed with water and then added to and dispersed in 500 parts by weight of distilled water to obtain resin particles having palladium attached thereto.

(2) Electroless nickel plating process

1000 mL of ion-exchanged water was added to the resin particles having palladium attached thereto, and sufficiently dispersed by using an ultrasonic processor to obtain a suspension. A nickel plating solution (pH 6.5) containing 0.23 mol / L nickel sulfate, 0.5 mol / L sodium hypophosphite and 0.5 mol / L sodium citrate was prepared. While the suspension was stirred at 30 캜, the nickel plating solution (pH 6.5) was gradually added dropwise to perform electroless nickel plating to form a first nickel plating layer having a thickness of 5 nm. After confirming that the foaming of hydrogen stopped, 1 g of an alumina slurry (average particle size: 50 nm) was added and dispersed for 10 minutes to obtain nickel plated particles (1) with inorganic particles attached thereto.

1000 mL of ion-exchanged water was added to the nickel plated particles (1) to which the inorganic particles had been attached, and sufficiently dispersed using an ultrasonic processor to obtain a suspension. A nickel plating solution (pH 8.5) containing 0.23 mol / L of nickel sulfate, 0.5 mol / L of sodium hypophosphite and 0.5 mol / L of sodium citrate was prepared. The above nickel plating solution (pH 8.5) was gradually added dropwise while stirring the suspension at 30 캜 to carry out electroless nickel plating of the nickel plating particles 1 with inorganic particles to form a second nickel plating layer having a thickness of 95 nm . After confirming that the foaming of hydrogen stopped, the particles were filtered out, washed with water, replaced with alcohol, and then vacuum-dried to obtain conductive particles having protrusions on the surface of the nickel plating layer.

Further, in the obtained conductive particles, the inorganic particles were harder than the conductive layer, and the Mohs hardness of the inorganic particles was larger than the Mohs hardness of the conductive layer. Further, in the obtained conductive particles, 100% (20% or more) of the total number of the plurality of inorganic particles was distant from the surface of the resin particles as the base particles.

(Example 2)

Conductive particles were obtained in the same manner as in Example 1 except that the alumina slurry (average particle diameter: 50 nm) was changed to a zirconia slurry (average particle diameter: 60 nm).

(Example 3)

Conductive particles were obtained in the same manner as in Example 1 except that the alumina slurry (average particle diameter: 50 nm) was changed to a silica slurry (average particle diameter: 20 nm).

(Example 4)

(1) Core material deposition process

The palladium-adhered resin particles obtained in Example 1 were prepared. This palladium-adhered resin particle was stirred and dispersed in 300 mL of ion-exchanged water for 3 minutes to obtain a dispersion. Next, 1 g of a metallic nickel particle slurry (average particle size 250 nm) was added to the dispersion for 3 minutes to obtain resin particles having a core material attached thereto.

(2) Electroless nickel plating process

1000 mL of ion-exchanged water was added to the resin particle to which the core material was adhered and sufficiently dispersed by using an ultrasonic processor to obtain a suspension. A nickel plating solution (pH 8.0) containing 0.25 mol / L of nickel sulfate, 0.25 mol / L of sodium hypophosphite and 0.5 mol / L of sodium citrate was prepared. While the suspension was stirred at 30 캜, the nickel plating solution (pH 8.0) was gradually dropped to perform electroless nickel plating of the resin particles having the core material attached thereto to form a first nickel plating layer having a thickness of 5 nm. After confirming that the foaming of hydrogen stopped, 1 g of an alumina slurry (average particle size: 50 nm) was added and dispersed for 10 minutes to obtain nickel plated particles (1) with inorganic particles attached thereto.

1000 mL of ion-exchanged water was added to the nickel plated particles (1) to which the inorganic particles had been attached, and sufficiently dispersed using an ultrasonic processor to obtain a suspension. A nickel plating solution (pH 8.0) containing 0.25 mol / L of nickel sulfate, 0.25 mol / L of sodium hypophosphite and 0.5 mol / L of sodium citrate was prepared. The nickel plating solution (pH 8.0) was gradually added dropwise while stirring the suspension at 30 캜 to carry out electroless nickel plating of the nickel plating particles 1 with inorganic particles to form a second nickel plating layer with a thickness of 95 nm Respectively. After confirming that the foaming of hydrogen stopped, the particles were filtered out, washed with water, replaced with alcohol, and then vacuum-dried to obtain conductive particles having projections on the outer surface of the nickel plated layer.

(Comparative Example 1)

(1) palladium deposition process

(2) Step of attaching inorganic particles

The resin particles having palladium attached thereto were stirred and dispersed in 300 mL of ion-exchanged water for 3 minutes to obtain a dispersion. Next, 1 g of an alumina slurry (average particle diameter: 50 nm) was added to the dispersion for 3 minutes to obtain resin particles having inorganic particles adhered thereto. In the resin particle to which the obtained inorganic particle was attached, all of the inorganic particle was in contact with the resin particle.

(3) Electroless nickel plating process

A nickel plating solution (pH 8.0) containing 0.25 mol / L of nickel sulfate, 0.25 mol / L of sodium hypophosphite and 0.5 mol / L of sodium citrate was prepared. The nickel plating solution (pH 8.0) was gradually dropped while stirring the particle slurry with the inorganic particles attached thereto at 60 占 폚 to carry out electroless nickel plating to form a nickel plating layer having a thickness of 100 nm. After confirming that the foaming of hydrogen stopped, the particles were collected by filtration, washed with water, replaced with alcohol, and vacuum-dried to obtain conductive particles having protrusions on the surface of the nickel plating layer.

(Example 5)

(1) palladium deposition process

10 parts by weight of the resin particles were dispersed in 100 parts by weight of an alkali solution containing 5% by weight of a palladium catalyst solution using an ultrasonic disperser, and the solution was filtered to take out the resin particles. Subsequently, the resin particles were added to 100 parts by weight of a 1 wt% solution of dimethylamine borane to activate the surface of the resin particles. The surface-activated resin particles were sufficiently washed with water, and then dispersed in 500 parts by weight of distilled water to obtain a dispersion containing resin particles having palladium attached thereto.

(2) Core material deposition process

1 g of a metallic nickel particle slurry (average particle diameter 250 nm) was added to the aqueous dispersion over 3 minutes, 1 g of an alumina slurry (average particle diameter 50 nm) was further added and dispersed for 10 minutes to obtain metallic nickel particles 1 having alumina adhered thereto . Next, the metallic nickel particles (1) were added to a dispersion containing resin particles having palladium attached thereto to obtain a slurry containing particles having the core material attached thereto.

(3) Electroless nickel plating process

A nickel plating solution (pH 8.0) containing 0.25 mol / L of nickel sulfate, 0.25 mol / L of sodium hypophosphite and 0.5 mol / L of sodium citrate was prepared. While stirring the slurry containing the core material-adhered particles at 60 캜, the nickel plating solution (pH 8.0) was gradually dropped into the slurry to perform electroless nickel plating. After confirming that the foaming of hydrogen stopped, the particles were filtered out, washed with water, replaced with alcohol, and vacuum-dried to obtain conductive particles having projections on the outer surface of the nickel plating layer having a thickness of 100 nm.

Further, in the obtained conductive particles, the inorganic particles were harder than the conductive layer, and the Mohs hardness of the inorganic particles was larger than the Mohs hardness of the conductive layer. Further, in the obtained conductive particles, at least 20% of the total number of the plurality of inorganic particles was kept at a distance without contacting the surface of the resin particles as the base particles.

(Example 6)

Conductive particles were obtained in the same manner as in Example 5 except that the alumina slurry (average particle diameter: 50 nm) was changed to a zirconia slurry (average particle diameter: 60 nm).

(Example 7)

Conductive particles were obtained in the same manner as in Example 5 except that the alumina slurry (average particle diameter: 50 nm) was changed to a silica slurry (average particle diameter: 20 nm).

(Example 8)

(1) Fabrication of insulating particles

In a 1000 mL separable flask equipped with a four-neck separable cover, a stirrer, a three-way cock, a cooling tube and a temperature probe, 100 mmol of methyl methacrylate and 100 mmol of N, N, N-trimethyl- A monomer composition containing 1 mmol of monooxyethylammonium chloride and 1 mmol of 2,2'-azobis (2-amidinopropane) dihydrochloride was weighed in ion-exchange water to a solid content of 5% by weight and taken at 200 rpm And the mixture was stirred for 24 hours at 70 캜 in a nitrogen atmosphere. After completion of the reaction, the resultant was lyophilized to obtain insulating particles having an ammonium group on the surface and having an average particle diameter of 220 nm and a CV value of 10%.

The insulating particles were dispersed in ion-exchanged water under ultrasonic irradiation to obtain a 10% by weight aqueous dispersion of insulating particles.

10 g of the conductive particles obtained in Example 1 were dispersed in 500 ml of ion-exchanged water, 4 g of an aqueous dispersion of insulating particles was added, and the mixture was stirred at room temperature for 6 hours. The mixture was filtered with a 3 탆 mesh filter, then washed with methanol and dried to obtain conductive particles with insulating particles adhered thereto.

As a result of observation with a scanning electron microscope (SEM), only one coating layer formed of insulating particles was formed on the surface of the conductive particles. The coated area of the insulating particles (i.e., the projected area of the particle size of the insulating particles) with respect to the area of 2.5 mu m from the center of the conductive particles was calculated by image analysis. As a result, the coverage was 30%.

(Examples 9 to 14)

Conductive particles with insulating particles were obtained in the same manner as in Example 8 except that the conductive particles obtained in Example 1 were replaced with the conductive particles obtained in the following Examples.

Example 9: Change to conductive particles obtained in Example 2

Example 10: Change to conductive particles obtained in Example 3

Example 11: Change to conductive particles obtained in Example 4

Example 12: Change to conductive particles obtained in Example 5

Example 13: Change to conductive particles obtained in Example 6

Example 14: Change to conductive particles obtained in Example 7

(evaluation)

(1) Fabrication of a connection structure

10 parts by weight of a bisphenol A type epoxy resin ("Epikote 1009" manufactured by Mitsubishi Chemical Corporation), 40 parts by weight of an acrylic rubber (weight average molecular weight: about 800,000), 200 parts by weight of methyl ethyl ketone, , And 2 parts by weight of a silane coupling agent ("SH6040 ", manufactured by Toray Dow Corning Silicone Co., Ltd.) were added and dispersed so that the content of the conductive particles was 3 wt% To obtain a resin composition.

The resulting resin composition was applied to a PET (polyethylene terephthalate) film having a thickness of 50 占 퐉 on one side of which had been subjected to release treatment and dried for 5 minutes by hot air at 70 占 폚 to prepare an anisotropic conductive film. The thickness of the resulting anisotropic conductive film was 12 占 퐉.

The resulting anisotropic conductive film was cut into a size of 5 mm x 5 mm. The cut anisotropic conductive film was placed on a glass substrate (3 cm wide, 3 cm long) provided with aluminum electrodes (height 0.2 탆, L / S = 20 탆 / 20 탆) The center was attached. Subsequently, a two-layer flexible printed substrate (width 2 cm, length 1 cm) provided with the same aluminum electrode was positioned and aligned so that electrodes were overlapped with each other, and then bonded. The laminate of the glass substrate and the double-layer flexible print substrate was subjected to thermocompression bonding under conditions of 10 N, 180 캜 and 20 seconds to obtain a connection structure. Further, a two-layer flexible printed substrate having an aluminum electrode directly formed on a polyimide film was used.

(2) Connection resistance

The connection resistance between the opposing electrodes of the connection structure obtained in the above (1) production of the connection structure was measured by the four-terminal method. Further, the connection resistance was judged based on the following criteria.

[Criteria for judging connection resistance]

○: Connection resistance is 3.0Ω or less

?: Connection resistance is more than 3.0?, Not more than 5.0?

×: Connection resistance exceeded 5.0Ω

The results are shown below.

[Connection resistance determination result]

Example 1:

Example 2:

Example 3:

Example 4:

Comparative Example 1:

Example 5:

Example 6:

Example 7:

Example 8:

Example 9:

Example 10:

Example 11:

Example 12:

Example 13:

Example 14:

In addition, in the conductive particles obtained in all the examples, at least five inorganic particles were arranged inside one projection on the outer surface of the conductive layer. In Examples 5 to 7 and 12 to 14, one core material is disposed inside one projection on the outer surface of the conductive layer, and one projection on the outer surface of the conductive layer and a core material disposed on the inner side of the projection And a plurality of inorganic particles were arranged in at least five layers. In Examples 5 to 7 and 12 to 14, a conductive layer was disposed between the surface of many inorganic particles and the surface of the base particles, and the core material was disposed. Further, in Examples 5 to 7 and 12 to 14, since a composite having inorganic particles adhered to the core material was used, many inorganic particles were in contact with the core material. Further, in Examples 1 to 4 and 8 to 11, the plurality of inorganic particles were localized so as to exist more inside the protrusions on the outer surface of the conductive layer than on the inside of the outer surface portion of the conductive layer without protrusions.

1: conductive particle 2: base particle
3: conductive layer 3a: projection
4: core material 5: inorganic particles
6: Insulating material 11: Conductive particle
12: conductive layer 12a:
13: core material 14: inorganic particles
21: conductive particles 22: conductive layer
22a: projection 23: inorganic particle
51: connection structure 52: first connection object member
52a: upper surface 52b: electrode
53: second connection target member 53a:
53b: electrode 54:

Claims

Base particles,
A conductive layer disposed on the surface of the base particle and having a plurality of projections on an outer surface thereof,
Embedded in the conductive layer (

A plurality of inorganic particles,
The inorganic particles are embedded in the conductive layer and are different from the core material forming the protrusions on the outer surface of the conductive layer,
The inorganic particles are disposed on the inner side of the projections on the outer surface of the conductive layer,
Wherein the inorganic particles of at least a part of the plurality of inorganic particles are not in contact with the surface of the base particles.

The conductive particle according to claim 1, wherein a plurality of the inorganic particles are disposed inside one of the projections on the outer surface of the conductive layer.

3. The conductive particle according to claim 1 or 2, wherein at least 20% of the total number of the plurality of inorganic particles is not in contact with the surface of the base particles.

3. The conductive particle according to claim 1 or 2, wherein the distance between the inorganic particles not in contact with the surface of the base particles and the base particles is 5 nm or more.

3. The semiconductor device according to claim 1 or 2, further comprising a plurality of core materials buried in the conductive layer,
And the core material is embedded in the conductive layer, whereby the protrusions are formed on the outer surface of the conductive layer.

6. The semiconductor device according to claim 5, wherein the core material is arranged on the inner side of the projection on the outer surface of the conductive layer,
Wherein the inorganic particles are disposed between one of the projections on the outer surface of the conductive layer and the core material disposed on the inside of the projection.

The conductive particle according to claim 5, wherein the plurality of inorganic particles are in contact with the core material.

The conductive particle according to claim 5, wherein the inorganic particles are adhered on the surface of the core material, and the core material and the inorganic particles form a composite.

The conductive particle according to claim 5, wherein the core material is a metal particle.

3. The conductive particle according to claim 1 or 2, wherein the plurality of inorganic particles are localized so as to exist more on the outer surface side than the inner surface side of the conductive layer.

The conductive particle according to claim 1 or 2, further comprising an insulating material attached to a surface of the conductive layer.

A conductive material comprising the conductive particles according to claim 1 or 2 and a binder resin.

A first connecting object member, a second connecting object member, and a connecting portion connecting the first and second connecting object members,
Wherein the connecting portion is formed by the conductive particles according to claim 1 or 2, or is formed by a conductive material including the conductive particles and a binder resin.