TWI820157B - Conductive particles, conductive materials and connection structures - Google Patents

Abstract

The present invention provides conductive particles that can effectively reduce the connection resistance between electrodes and effectively suppress magnetic aggregation. The conductive particles of the present invention include base particles and a conductive portion arranged on the surface of the base particles, and the ratio of residual magnetization to saturation magnetization is 0.6 or less.

Description

Conductive particles, conductive materials and connection structures

The present invention relates to conductive particles in which a conductive part is arranged on the surface of a base particle. Furthermore, the present invention relates to a conductive material and a connection structure using the above-mentioned conductive particles.

Anisotropic conductive materials such as anisotropic conductive paste and anisotropic conductive film are widely known. In this anisotropic conductive material, conductive particles are dispersed in a binder resin. Moreover, as electroconductive particle, the electroconductive particle which performed insulation treatment on the surface of a conductive layer may be used.

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

As an example of the above-mentioned conductive particles, the following Patent Document 1 discloses conductive particles including a mother particle having a plating layer and insulating daughter particles covering the surface of the mother particle. The above-mentioned mother particles are particles whose surface of the plastic core is covered with the above-mentioned plating layer. The above-mentioned plating layer has at least a nickel/phosphorus alloy layer. The particle diameter of the above-mentioned mother particles is 2.0 μm or more and 3.0 μm or less. The saturation magnetization of the above-mentioned mother particles is 45 emu/cm ³ or less. The particle diameter of the above-mentioned insulator particles is 180 nm or more and 500 nm or less. [Prior art documents] [Patent documents]

[Patent Document 1] Japanese Patent Application Publication No. 2013-258138

[Problem to be solved by the invention]

In the above-mentioned Patent Document 1, the saturation magnetization of the above-mentioned mother particles is 45 emu/cm ³ or less. However, Patent Document 1 only describes controlling the saturation magnetization within a specific range, and does not describe at all about the residual magnetization.

Conventional conductive particles have conductive metals such as nickel on the surface through plating, etc., which are used for electrical connection between electrodes. Furthermore, in conventional conductive particles, there is a case where magnetic metals such as nickel are magnetized due to the surrounding environment or manufacturing steps, and the conductive particles aggregate (magnetic aggregation). As a method to solve the above-mentioned problems, there is a method of reducing saturation magnetization by containing phosphorus in the plating layer, as described in Patent Document 1 and the like. However, if the phosphorus content of the plating layer increases, the resistance value of the conductive particles will significantly increase. If the conductive particles are used to electrically connect the electrodes, the connection resistance between the electrodes will also increase. .

Furthermore, in conventional conductive particles, although the saturation magnetization can be reduced, it is sometimes difficult to sufficiently reduce the residual magnetization. In order to suppress the magnetic aggregation of conductive particles, it is necessary to reduce not only the saturation magnetization but also the residual magnetization. In conventional conductive particles, it was difficult to achieve both reduction in connection resistance between electrodes and suppression of magnetic aggregation.

An object of the present invention is to provide conductive particles that can effectively reduce the connection resistance between electrodes and effectively suppress magnetic aggregation. Furthermore, an object of the present invention is to provide a conductive material and a connection structure using the above-mentioned conductive particles. [Technical means to solve problems]

According to a broad aspect of the present invention, there is provided electrically conductive particles including base particles and conductive portions disposed on the surfaces of the base particles, and in which the ratio of residual magnetization to saturation magnetization is 0.6 or less.

In a specific aspect of the conductive particles of the present invention, the residual magnetization is 0.02 A/m or less.

In a specific aspect of the conductive particles of the present invention, they include a soft magnetic body portion disposed on an outer surface of the conductive portion.

In a specific aspect of the conductive particles of the present invention, they include an insulating part disposed between the conductive part and the soft magnetic part, and the soft magnetic part is disposed between the conductive part and the insulating part. on the outer surface.

In a specific aspect of the conductive particles of the present invention, the distance between the conductive part and the soft magnetic part is 10 nm or more and 500 nm or less.

In a specific aspect of the conductive particles of the present invention, the conductive particles include a plurality of the soft magnetic body parts, and the plurality of soft magnetic body parts are separately arranged on the outer surface of the conductive part.

In a specific aspect of the conductive particles of the present invention, the area of the portion of the surface of the conductive part covered by the soft magnetic body part accounts for more than 30% of the entire surface area of the conductive part.

In a specific aspect of the conductive particles of the present invention, the area of the portion of the surface of the conductive part covered by the soft magnetic body part accounts for more than 40% of the entire surface area of the conductive part.

In a specific aspect of the conductive particles of the present invention, the conductive particles include a plurality of insulating particles arranged on the outer surface of the conductive part.

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

According to a broad aspect of the present invention, there is provided a connection structure including: a first connection object member having a first electrode on its surface, a second connection object member having a second electrode on its surface, and connecting the first connection object member and The connecting portion of the above-mentioned second connection object member; and the material of the above-mentioned connecting portion is the above-mentioned conductive particles, or a conductive material containing the above-mentioned conductive particles and a binder resin, and the above-mentioned first electrode and the above-mentioned second electrode are formed by the above-mentioned conductivity The above-mentioned conductive parts in the particles are electrically connected. [Effects of the invention]

The conductive particles of the present invention include base particles and conductive portions arranged on the surfaces of the base particles. In the conductive particles of the present invention, the ratio of residual magnetization to saturation magnetization is 0.6 or less. Since the conductive particles of the present invention have the above-mentioned structure, the connection resistance between electrodes can be effectively reduced and magnetic aggregation can be effectively suppressed.

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

(Conductive particles) The conductive particles of the present invention include base particles and conductive portions arranged on the surfaces of the base particles. In the conductive particles of the present invention, the ratio of residual magnetization to saturation magnetization is 0.6 or less.

Since the conductive particles of the present invention have the above-mentioned structure, the connection resistance between electrodes can be effectively reduced and magnetic aggregation can be effectively suppressed.

In the case of conventional conductive particles, magnetic metals such as nickel are magnetized due to the surrounding environment or manufacturing steps, and the conductive particles aggregate (magnetic aggregation). As a method of suppressing aggregation (magnetic aggregation) of conductive particles, a method of reducing saturation magnetization by containing phosphorus in the plating layer can be cited. However, if the phosphorus content of the plating layer increases, the resistance value of the conductive particles will significantly increase. If the conductive particles are used to electrically connect the electrodes, the connection resistance between the electrodes will also increase. .

Furthermore, in the conventional conductive particles, even if the saturation magnetization is reduced, the residual magnetization may not be sufficiently reduced. The inventors found that in order to suppress the magnetic aggregation of conductive particles, it is necessary to reduce the residual magnetization. In conventional conductive particles, it was sometimes difficult to achieve both reduction in connection resistance between electrodes and suppression of magnetic aggregation.

The present inventors have found that by using specific conductive particles, it is possible to achieve both reduction in connection resistance between electrodes and suppression of magnetic aggregation of conductive particles. In the present invention, since it has the above-mentioned structure, the connection resistance between the electrodes can be effectively reduced, and the magnetic aggregation of the conductive particles can be effectively suppressed.

In the present invention, in order to obtain the above-mentioned effects, the use of specific conductive particles makes a great contribution.

From the viewpoint of effectively reducing the connection resistance between electrodes and effectively suppressing magnetic aggregation, in the conductive particles of the present invention, the ratio of residual magnetization to saturation magnetization (residual magnetization/saturation magnetization) is 0.6 or less. The ratio (residual magnetization/saturation magnetization) is preferably 0.5 or less, more preferably 0.3 or less, and most preferably 0.0. From the viewpoint of further effectively reducing the connection resistance between electrodes and further effectively suppressing magnetic aggregation, the closer the above-mentioned ratio (residual magnetization/saturation magnetization) is to 0.0, the better. If the ratio (residual magnetization/saturation magnetization) is equal to or less than the upper limit, the connection resistance between the electrodes can be further effectively reduced, and magnetic aggregation can be further effectively suppressed. In addition, the lower limit of the above-mentioned ratio (residual magnetization/saturation magnetization) is not particularly limited. The ratio (residual magnetization/saturation magnetization) is, for example, preferably 0.001 or more, more preferably 0.01 or more.

From the viewpoint of further effectively suppressing magnetic aggregation, the residual magnetization of the conductive particles is preferably 0.02 A/m (20 emu/cm ³ ) or less. The above-mentioned residual magnetization is preferably 0.015 A/m (15 emu/cm ³ ) or less, more preferably 0.01 A/m (10 emu/cm ³ ) or less, still more preferably 0.005 A/m (5 emu/cm ³ ) Below, the optimal value is 0.0000 A/m (0.0 emu/cm ³ ). From the viewpoint of further effectively suppressing magnetic aggregation, the closer the residual magnetization is to 0.0000 A/m (0.0 emu/cm ³ ), the better. If the residual magnetization is below the upper limit, the connection resistance between the electrodes can be further effectively reduced, and magnetic aggregation can be further effectively suppressed. Furthermore, the lower limit of the residual magnetization of the conductive particles is not particularly limited. The residual magnetization is preferably 0.0001 A/m (0.1 emu/cm ³ ) or more, for example.

The residual magnetization of the conductive particles can be controlled, for example, by adjusting the coverage ratio of the soft magnetic body portion described below. For example, if the coverage ratio of the soft magnetic body portion is increased, the above-mentioned residual magnetization can be reduced, and if the coverage ratio of the soft magnetic body portion is reduced, the above-mentioned residual magnetization can be increased.

From the viewpoint of further effectively suppressing magnetic aggregation, the saturation magnetization of the conductive particles is preferably 0.2 A/m (200 emu/cm ³ ) or less. The above-mentioned saturation magnetization is preferably 0.1 A/m (100 emu/cm ³ ) or less, more preferably 0.08 A/m (80 emu/cm ³ ) or less, still more preferably 0.05 A/m (50 emu/cm ³ ) the following. If the saturation magnetization is equal to or less than the upper limit, magnetic aggregation can be suppressed more effectively. From the viewpoint of magnetic concentration, the saturation magnetization of the conductive particles is preferably 0.001 A/m (1 emu/cm ³ ) or more. The above-mentioned saturation magnetization is preferably 0.005 A/m (5 emu/cm ³ ) or more, more preferably 0.01 A/m (10 emu/cm ³ ) or more, further preferably 0.015 A/m (15 emu/cm ³ ) above. If the saturation magnetization is equal to or higher than the lower limit, the conductive particles in the anisotropic conductive material can be efficiently aligned by an external magnetic field.

The saturation magnetization of the conductive particles can be controlled, for example, by adjusting the thickness of the conductive layer or the conductive part. For example, if the thickness of the conductive layer or the conductive part is increased, the saturation magnetization can be increased, and if the thickness of the conductive layer or the conductive part is made thin, the saturation magnetization can be decreased.

The residual magnetization and saturation magnetization of the above-mentioned conductive particles can be measured using a vibration sample type magnetometer ("PV-300-5" manufactured by Toei Scientific Industrial Co., Ltd.). Specifically, it can be measured as follows.

A capsule filled with nickel powder is used as the calibration sample of the device to calibrate the vibration sample type magnetometer. Next, the conductive particles are weighed in the capsule and installed in the sample holder. The sample holder was placed on the magnetometer body, and the magnetization curve was obtained by measuring under the conditions of a temperature of 20°C (constant temperature), a maximum applied magnetic field of 20 kOe, and a speed of 3 min/loop. The residual magnetization and saturation magnetization (A/m) are calculated based on the obtained magnetization curve.

The particle diameter of the above-mentioned conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 100 μm or less, more preferably 60 μm or less, more preferably 30 μm or less, and still more preferably 10 μm or less, Particularly preferably, it is 5 μm or less. If the particle diameter of the conductive particles is above the lower limit and below the upper limit, when the conductive particles are used to connect electrodes, the contact area between the conductive particles and the electrodes becomes sufficiently large, and conductive particles are formed. It is difficult to form agglomerated conductive particles. In addition, the distance between the electrodes connected via the conductive particles will not be too large, and the conductive portion will be difficult to peel off from the surface of the base particle.

The particle size of the conductive particles is preferably an average particle size, more preferably a number average particle size. The particle size of the conductive particles is determined, for example, by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope, calculating the average particle size of each conductive particle, or performing laser diffraction particle size distribution. Determination. In observation with an electron microscope or an optical microscope, the particle diameter of each conductive particle is determined as the particle diameter in terms of equivalent circular diameter. In the observation by an electron microscope or an optical microscope, the average particle diameter in terms of circular equivalent diameter and the average particle diameter in terms of spherical equivalent diameter of any 50 conductive particles are approximately equal. In the laser diffraction particle size distribution measurement, the particle diameter per conductive particle is determined as the particle diameter in terms of spherical equivalent diameter. The particle size of the conductive particles is preferably calculated by laser diffraction particle size distribution measurement.

The coefficient of variation (CV value) of the particle diameter of the conductive particles is preferably 10% or less, more preferably 5% or less. If the variation coefficient of the particle diameter of the conductive particles is below the upper limit, the conduction reliability and insulation reliability between electrodes can be further effectively improved.

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

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

The shape of the above-mentioned conductive particles is not particularly limited. The shape of the above-mentioned conductive particles may be spherical or may be flat or other shapes other than spherical shapes.

Hereinafter, specific embodiments of the present invention will be 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.

Conductive particles 1 shown in FIG. 1 include base particles 2 and conductive parts 3 . In the conductive particle 1, the conductive part 3 is a conductive layer. The conductive part 3 covers the surface of the base particle 2 . The conductive particles 1 are coated particles in which the surface of the base particle 2 is covered with the conductive part 3 . The conductive particle 1 has the conductive part 3 on the surface. In the conductive particle 1, the conductive part 3 is a single-layer conductive part (conductive layer). In the above-mentioned conductive particles, the above-mentioned conductive part may cover the entire surface of the above-mentioned base material particle, and the above-mentioned conductive part may also cover part of the surface of the above-mentioned base material particle. In the above-mentioned conductive particles, the above-mentioned conductive part may be a single-layer conductive part or a multi-layer conductive part including two or more layers.

The conductive particles 1 are different from the conductive particles 51 described below in that they do not have a core material. The conductive particles 1 do not have protrusions on the conductive surface, and do not have protrusions on the outer surface of the conductive part 3 . The conductive particles 1 are spherical. However, the conductive particles 1 may have a core material, may have protrusions on the conductive surface, or may have protrusions on the outer surface of the conductive part 3 .

The above-mentioned conductive particles may not have protrusions on the conductive surface, may not have protrusions on the surface outside the conductive part, and may be spherical. In addition, the conductive particle 1 is different from the conductive particles 11, 21, 41, and 51 described below in that it does not have insulating particles. However, the conductive particles 1 may have insulating particles arranged on the outer surface of the conductive part 3 .

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

Conductive particles 11 shown in FIG. 2 include base particles 2 , conductive parts 3 , soft magnetic parts 12 and insulating particles 13 . The insulating particles 13 are made of an insulating material.

The conductive particles 11 are different from the conductive particles 1 and have a soft magnetic body part 12 and insulating particles 13 . The conductive particles 11 include insulating particles 13 that are not in contact with the soft magnetic body part 12 .

The conductive particles may or may not have a soft magnetic body part. The above-mentioned conductive particles may or may not include insulating particles. In the above-mentioned conductive particles, it is preferable that the above-mentioned soft magnetic body part is arranged on the outer surface of the above-mentioned conductive part. The soft magnetic body part is preferably not in contact with the conductive part. Among the above-mentioned conductive particles, the above-mentioned insulating particles are preferably arranged on the outer surface of the above-mentioned conductive part.

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

Conductive particles 21 shown in FIG. 3 include base particles 2 , conductive parts 3 , soft magnetic parts 12 and insulating particles 13 .

The conductive particles 21 are different from the conductive particles 11 in that they have an insulating portion 22 covering the surface of the soft magnetic body portion 12 . The conductive particles 21 include insulating particles 13 that are not in contact with the soft magnetic body part 12 . The conductive particles 21 include insulating particles 13 that are not in contact with the insulating part 22 .

The insulating part 22 is made of an insulating material. In the conductive particles 21 , the insulating portion 22 covers the entire surface of the soft magnetic body portion 12 . Therefore, the insulating portion 22 is disposed between the conductive portion 3 and the soft magnetic body portion 12 . The soft magnetic body part 12 is not in contact with the conductive part 3 . The insulating part only needs to cover at least a part of the surface of the soft magnetic part, and does not need to cover the entire surface of the soft magnetic part. In the above-mentioned conductive particles, it is preferable that the above-mentioned soft magnetic body part is arranged on the outer surface of the above-mentioned conductive part. The soft magnetic body portion is preferably disposed on the outer surface of the conductive portion with the insulating portion interposed therebetween. The insulating part is preferably disposed between the conductive part and the soft magnetic body part. The conductive particles may or may not contain insulating particles.

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

Conductive particles 31 shown in FIG. 4 include base particles 2 , conductive parts 3 and soft magnetic parts 12 .

The conductive particles 31 are different from the conductive particles 11 in that they have the insulating part 32 covering the surface of the conductive part 3 .

The insulating portion 32 is made of an insulating material. In the conductive particles 31 , the insulating part 32 covers the entire surface of the conductive part 3 . Therefore, the insulating portion 32 is arranged between the conductive portion 3 and the soft magnetic body portion 12 . The soft magnetic body part 12 is not in contact with the conductive part 3 . The above-mentioned insulating part only needs to cover at least a part of the surface of the above-mentioned conductive part, and does not need to cover the entire surface of the above-mentioned conductive part. In the above-mentioned conductive particle, the above-mentioned soft magnetic body part is preferably arranged on the outer surface of the above-mentioned conductive part with the above-mentioned insulating part interposed. The insulating part is preferably disposed between the conductive part and the soft magnetic body part. The conductive particles may include insulating particles arranged on the outer surface of the conductive part.

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

Conductive particles 41 shown in FIG. 5 include base particles 2 , conductive parts 3 , soft magnetic parts 12 and insulating particles 13 .

The conductive particles 41 are different from the conductive particles 11 in that they have an insulating part 42 arranged on the outer surface of the conductive part 3 . The conductive particles 41 include insulating particles 13 that are not in contact with the soft magnetic body part 12 . The conductive particles 41 include insulating particles 13 that are not in contact with the insulating part 42 .

The insulating portion 42 is made of an insulating material. In the conductive particles 41, the insulating part 42 is an insulating particle. In the conductive particles 41 , the insulating part 42 is arranged on the outer surface of the conductive part 3 , and the soft magnetic body part 12 is arranged on the outer surface of the insulating part 42 . Therefore, the insulating portion 42 is arranged between the conductive portion 3 and the soft magnetic body portion 12 . The soft magnetic body part 12 is not in contact with the conductive part 3 . The insulating part only needs to cover at least a part of the surface of the conductive part, and does not need to cover the entire surface of the conductive part. In the above-mentioned conductive particles, it is preferable that the above-mentioned soft magnetic body part is arranged on the outer surface of the above-mentioned conductive part with the above-mentioned insulating part interposed. The insulating part is preferably disposed between the conductive part and the soft magnetic body part. The conductive particles may or may not contain insulating particles.

FIG. 6 is a cross-sectional view showing conductive particles according to the sixth embodiment of the present invention.

Conductive particles 51 shown in FIG. 6 include base particles 2 , conductive parts 61 , soft magnetic parts 12 and insulating particles 13 .

The conductive particles 51 are different from the conductive particles 21 in that they have a plurality of core substances 62 arranged on the surface of the base particle 2 . The conductive part 61 covers the base particles 2 and the core material 62 . Since the conductive part 61 covers the core material 62, the conductive particles 51 have a plurality of protrusions 63 on the surface. In the conductive particles 51, the surface of the conductive portion 61 is raised due to the core material 62, and a plurality of protrusions 63 are formed. In the above-mentioned conductive particles, in order to form the above-mentioned protrusions, the above-mentioned core material may be used, and the above-mentioned core material may not be used. The above-mentioned conductive particles do not need to have the above-mentioned core substance.

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

Substrate particles: Examples of the substrate particles include resin particles, inorganic particles other than metal particles, organic-inorganic hybrid particles, and metal particles. The above-mentioned substrate particles are preferably substrate particles other than metal particles, more preferably resin particles, inorganic particles other than metal particles, or organic-inorganic mixed particles. The base particle may be a core-shell particle including a core and a shell disposed on the surface of the core. The core may be an organic core, and the shell may be an inorganic shell.

As the material of the above-mentioned resin particles, various organic substances can be suitably used. Examples of materials for the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; polymethylmethacrylate; Acrylic resins such as polymethyl acrylate; polycarbonate, polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenolic resin, melamine resin, benzoguanamine resin, urea Resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polypropylene, polyphenylene ether, polyacetal, polyimide, polyamideimide, polyamide Ether ether ketone, polyether styrene, divinylbenzene polymers and divinylbenzene copolymers, etc. Examples of the divinylbenzene-based copolymer include divinylbenzene-styrene copolymers, divinylbenzene-(meth)acrylate copolymers, and the like. Since the hardness of the above-mentioned resin particles can be easily controlled within an appropriate range, the material for the above-mentioned resin particles is preferably a polymer obtained by polymerizing one or more types of polymerizable monomers having an ethylenically unsaturated group. things.

When the above-mentioned resin particles can be obtained by polymerizing a polymerizable monomer having an ethylenically unsaturated group, examples of the polymerizable monomer having an ethylenically unsaturated group include non-crosslinkable monomers and crosslinkable monomers. Single body.

Examples of the non-crosslinkable monomer include styrenic monomers such as styrene and α-methylstyrene; carboxyl group-containing monomers such as (meth)acrylic acid, maleic acid, and maleic anhydride. Monomer; methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (meth)acrylate )(Meth)acrylic acid alkyl esters such as lauryl acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate and isopropyl (meth)acrylate Compounds; (meth)acrylates containing oxygen atoms such as 2-hydroxyethyl (meth)acrylate, glyceryl (meth)acrylate, polyoxyethylene (meth)acrylate, and glycidyl (meth)acrylate. Compounds; nitrile-containing monomers such as (meth)acrylonitrile; vinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether and propyl vinyl ether; vinyl acetate, vinyl butyrate, vinyl laurate and vinyl acid ester compounds such as vinyl stearate; unsaturated hydrocarbons such as ethylene, propylene, isoprene and butadiene; (meth)trifluoromethyl acrylate, (meth)pentafluoroethyl acrylate, chlorine Halogen-containing monomers such as ethylene, vinyl fluoride, and chlorostyrene.

Examples of the crosslinkable monomer include tetramethylolmethane tetra(meth)acrylate, tetramethylolmethane tri(meth)acrylate, and tetramethylolmethane di(meth)acrylate. , trimethylolpropane tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, glyceryl tri(meth)acrylate, glyceryl di(meth)acrylate Ester, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, (poly)tetramethylene glycol di(meth)acrylate and 1,4-butyl Polyfunctional (meth)acrylate compounds such as glycol di(meth)acrylate; (iso)triallyl cyanurate, triallyl trimellitate, divinylbenzene, diallyl phthalate ester, diallylacrylamide, diallyl ether, and γ-(meth)acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, and vinyltrimethoxysilane, etc. Silane-containing monomers, etc.

"(Meth)acrylate" means one or both of "acrylate" and "methacrylate". "(Meth)acrylic group" means one or both of "acrylic group" and "methacrylic group". "(Meth)acrylyl" means one or both of "acrylyl" and "methacrylyl".

The above-mentioned resin particles can be obtained by polymerizing the above-mentioned 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 using non-crosslinked seed particles together with a radical polymerization initiator to swell a monomer to perform polymerization.

When the above-mentioned base material particles are inorganic particles other than metal or organic-inorganic mixed particles, examples of inorganic substances used to form the base material particles include: silicon dioxide, alumina, barium titanate, zirconium oxide, and carbon black. wait. It is preferable that the above-mentioned inorganic substance is not a metal. The particles formed of the above-mentioned silica are not particularly limited. For example, cross-linked polymer particles may be formed by hydrolyzing a silicide having two or more hydrolyzable alkoxysilyl groups and then calcining if necessary. The particles obtained. Examples of the organic-inorganic mixed particles include organic-inorganic mixed particles formed of a crosslinked alkoxysilane-based polymer and an acrylic resin.

The organic-inorganic hybrid particles are preferably core-shell type organic-inorganic hybrid particles having a core and a shell disposed on the surface of the core. The above-mentioned core is preferably an organic core. The above-mentioned shell is preferably an inorganic shell. From the viewpoint of effectively reducing the connection resistance between electrodes, the substrate particles are preferably organic-inorganic hybrid particles having an organic core and an inorganic shell disposed on the surface of the organic core.

Examples of the material of the organic core include the material of the above-mentioned resin particles.

Examples of materials for the inorganic shell include the inorganic substances listed as materials for the base particles. The material of the above-mentioned inorganic shell is preferably silicon dioxide. The above-mentioned inorganic shell is preferably formed by making a metal alkoxide into a shell-like object on the surface of the above-mentioned core by a sol-gel method, and then baking the shell-like object. The metal alkoxide is preferably a silane alkoxide. The above-mentioned inorganic shell is preferably formed of silane alkoxide.

When the above-mentioned substrate particles are metal particles, examples of metals used as the material of the metal particles include silver, copper, nickel, silicon, gold, titanium, and the like.

The particle diameter of the above-mentioned substrate particles is preferably 0.5 μm or more, more preferably 1 μm or more, further preferably 2 μm or more, preferably 100 μm or less, more preferably 60 μm or less, further preferably 50 μm or less. . If the particle diameter of the substrate particles is not less than the above lower limit and not more than the above upper limit, the distance between the electrodes becomes smaller, and even if the thickness of the conductive layer is increased, smaller conductive particles can be obtained. Furthermore, when a conductive part is formed on the surface of a base particle, it becomes difficult to agglomerate, and it becomes difficult to form agglomerated conductive particles.

The particle size of the above-mentioned substrate particles is preferably 2 μm or more and 50 μm or less. If the particle diameter of the base particles is in the range of 2 μm or more and 50 μm or less, it becomes difficult to aggregate when forming conductive portions on the surfaces of the base particles, and it becomes difficult to form aggregated conductive particles.

The particle diameter of the above-mentioned base material particles means the diameter when the base material particles are true spherical, and means the maximum diameter when the base material particles are not true spherical.

The particle diameter of the above-mentioned substrate particles represents the number average particle diameter. The particle diameter of the substrate particles is determined using a particle size distribution measuring device or the like. The particle diameter of the base material particles is preferably determined by observing 50 arbitrary base material particles with an electron microscope or an optical microscope and calculating the average value. When measuring the particle diameter of the above-mentioned substrate particles among the conductive particles, the measurement can be performed as follows, for example.

It was added to "Technovit 4000" manufactured by Kulzer Corporation so that the content of the conductive particles would be 30% by weight, and was dispersed to prepare an embedding resin for conductive particle inspection. An ion milling device (“IM4000” manufactured by Hitachi High-Technologies Co., Ltd.) was used to cut out a cross section of the conductive particles so as to be dispersed near the center of the conductive particles embedded in the resin for inspection. Then, a field emission scanning electron microscope (FE-SEM) was used, the image magnification was set to 25,000 times, 50 conductive particles were randomly selected, and the base particles of each conductive particle were observed. The particle diameter of the base particle in each conductive particle was measured, and the arithmetic mean was calculated as the particle diameter of the base particle.

Conductive part: The conductive part preferably contains metal. The metal constituting the conductive portion is not particularly limited. Examples of the metal include gold, silver, copper, platinum, palladium, zinc, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium, cadmium, and alloys thereof. In addition, as the above-mentioned metal, tin-doped indium oxide (ITO) may also be used. The above-mentioned metal may be a soft magnetic body. Only one type of the above-mentioned metal may be used, or two or more types may be used in combination. From the viewpoint of further reducing the connection resistance between electrodes, an alloy containing tin, nickel, palladium, copper or gold is preferred, and nickel or palladium is more preferred. In addition, in this specification, the conductive part is defined as follows: a powder sample is prepared using the same material as that constituting the conductive part, and the powder sample is measured using a "powder resistivity measurement system" manufactured by Mitsubishi Chemical Corporation. When the volume resistance value is specified, the volume resistance value is the part below 0.005 Ω·cm.

Furthermore, from the viewpoint of effectively improving conduction reliability, it is preferable that the conductive portion and the outer surface portion of the conductive portion contain nickel. The nickel content in 100% by weight of the conductive part containing nickel is preferably 10% by weight or more, more preferably 50% by weight or more, more preferably 60% by weight or more, further preferably 70% by weight or more, and particularly preferably 90% by weight. More than % by weight. The nickel content in 100% by weight of the above-mentioned nickel-containing conductive part may be 97% by weight or more, may be 97.5% by weight or more, or may be 98% by weight or more.

Furthermore, hydroxyl groups are often present on the surface of the conductive part due to oxidation. Normally, hydroxyl groups are present on the surface of the conductive part formed of nickel due to oxidation. Insulating particles can be arranged through chemical bonding on the surface of the conductive part having such a hydroxyl group (the surface of the conductive particles).

The above-mentioned conductive part may be formed of one layer. The above-mentioned conductive part may also be formed of a plurality of layers. That is, the conductive portion may have a laminated structure of two or more layers. When the conductive portion is formed of multiple layers, the metal constituting the outermost layer is preferably gold, nickel, palladium, copper or an alloy containing tin and silver, more preferably gold. When the metal constituting the outermost layer is such a preferable metal, the connection resistance between the electrodes becomes further low. In addition, when the metal constituting the outermost layer is gold, the corrosion resistance becomes even higher.

The method of forming the conductive portion on the surface of the above-mentioned substrate particles is not particularly limited. Examples of methods for forming the conductive portion include electroless plating, electroplating, physical collision, mechanochemical reaction, physical evaporation or physical adsorption, and metal powder or metal-containing methods. Methods for coating powder and adhesive paste on the surface of substrate particles, etc. The above-mentioned method of forming the conductive portion is preferably electroless plating, electroplating or physical impact. Examples of the above-mentioned physical evaporation methods include vacuum evaporation, ion plating, ion sputtering and other methods. In addition, in the above-mentioned physical collision method, for example, Thetacomposer (manufactured by Tokusu Works Co., Ltd.) can be used.

The thickness of the conductive portion is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 10 μm or less, more preferably 1 μm or less, and still more preferably 0.3 μm or less. If the thickness of the conductive portion is more than the above lower limit and less than the above upper limit, sufficient conductivity can be obtained, and the conductive particles will not become too hard, and the conductive particles will be sufficiently deformed during connection between electrodes.

When the above-mentioned conductive part is formed of a plurality of layers, the thickness of the outermost conductive part is preferably 0.001 μm or more, more preferably 0.01 μm or more, preferably 0.5 μm or less, and more preferably 0.1 μm or less. If the thickness of the conductive portion of the outermost layer is more than the lower limit and less than the upper limit, the conductive portion of the outermost layer becomes uniform, the corrosion resistance becomes sufficiently high, and the connection resistance between electrodes can be sufficiently reduced.

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

Core material: The conductive particles preferably have a plurality of protrusions on the outer surface of the conductive part. An oxide film is often formed on the surface of an electrode connected by conductive particles. When using conductive particles having protrusions on the surface of the conductive part, the above-mentioned oxide film can be effectively removed by the protrusions by arranging the conductive particles between the electrodes and performing pressure contact. Therefore, the electrodes and the conductive parts are in more reliable contact, and the connection resistance between the electrodes is further reduced. Furthermore, during the connection between electrodes, the insulating particles between the conductive particles and the electrodes can be effectively eliminated by the protrusions of the conductive particles. Therefore, the reliability of conduction between electrodes is further improved.

Examples of methods for forming the protrusions include: a method of attaching a core substance to the surface of a base particle and then forming a conductive portion by electroless plating; and a method of forming a conductive portion on the surface of a base particle by electroless plating. Then, the core material is attached, and the conductive part is formed by electroless plating. Other methods for forming the above-mentioned protrusions include: forming a first conductive portion on the surface of a base material particle, disposing a core material on the first conductive portion, and then forming a second conductive portion; and forming a second conductive portion on the base material. A method of adding a core material in the middle of forming a conductive part (first conductive part, second conductive part, etc.) on the surface of particles. In addition, in order to form protrusions, it is also possible to use: after forming a conductive part on the base material particles by electroless plating without using the above-mentioned core material, the plating is deposited in the shape of protrusions on the surface of the conductive part, and then electroless plating can be used to form protrusions. Methods of forming conductive parts by electrolytic plating, etc.

An example of a method for making the core material adhere to the surface of the base particles is to add the core material to a dispersion of the base particles, and to accumulate and adhere the core material to the surface of the base particles due to Vantage force. ; and a method in which a core substance is added to a container containing substrate particles, and the core substance is adhered to the surface of the substrate particles by mechanical action such as rotation of the container. From the viewpoint of controlling the amount of the adhered core substance, the method of attaching the core substance to the surface of the base particle is preferably a method of accumulating and attaching the core substance to the surface of the base particle in the dispersion liquid.

Examples of materials constituting the core material include conductive materials and non-conductive materials. Examples of the conductive material include metals, metal oxides, conductive non-metals such as graphite, and conductive polymers. Examples of the conductive polymer include polyacetylene and the like. Examples of the non-conductive material include silica, alumina, zirconia, and the like. From the viewpoint of further improving the conduction reliability between electrodes, the core material is preferably a metal.

The above-mentioned metals are not particularly limited. Examples of the metal include: gold, silver, copper, platinum, zinc, iron, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium, cadmium and other metals; and tin-lead Alloys, tin-copper alloys, tin-silver alloys, tin-lead-silver alloys, tungsten carbide and other alloys composed of two or more metals. From the viewpoint of further improving the conduction reliability between electrodes, the metal is preferably nickel, copper, silver or gold. The metal may be the same as the metal constituting the conductive part (conductive layer), or may be different.

The shape of the core material is not particularly limited. The shape of the core material is preferably block-like. Examples of core substances include granular lumps, agglomerated lumps in which a plurality of fine particles are aggregated, and amorphous lumps.

The average diameter (average particle diameter) of the core material 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. If the average diameter of the core material is above the above lower limit and below the upper limit, the connection resistance between electrodes can be effectively reduced.

The particle size of the core material is preferably an average particle size, more preferably a number average particle size. The particle size of the core material is determined, for example, by observing 50 arbitrary core materials with an electron microscope or an optical microscope, calculating the average particle size of each core material, or performing a laser diffraction particle size distribution measurement. In the observation with an electron microscope or an optical microscope, the particle diameter per core material is determined as the particle diameter in terms of equivalent circular diameter. In the observation by an electron microscope or an optical microscope, the average particle diameter of any 50 core materials in terms of circular equivalent diameter is approximately equal to the average particle diameter in terms of spherical equivalent diameter. In the laser diffraction particle size distribution measurement, the particle diameter per core material is determined as the particle diameter in terms of spherical equivalent diameter. The particle size of the core material is preferably calculated by laser diffraction particle size distribution measurement.

Insulating particles: The conductive particles preferably include a plurality of insulating particles arranged on the outer surface of the conductive part. In this case, if the above-mentioned conductive particles are used for connection between electrodes, short circuit between adjacent electrodes can be prevented. Specifically, when a plurality of conductive particles are in contact, since insulating particles are present between a plurality of electrodes, short circuiting not between upper and lower electrodes but between laterally adjacent electrodes can be prevented. Furthermore, when connecting between electrodes, by pressurizing the conductive particles using two electrodes, the insulating particles between the conductive part of the conductive particles and the electrodes can be easily eliminated. Furthermore, in the case of conductive particles having a plurality of protrusions on the outer surface of the conductive part, insulating particles between the conductive part and the electrode of the conductive particles can be further easily eliminated.

Examples of the material of the insulating particles include the materials of the resin particles and the inorganic substances listed as the materials of the base particles. The material of the insulating particles is preferably the material of the resin particles. The above-mentioned insulating particles are preferably the above-mentioned resin particles or the above-mentioned organic-inorganic hybrid particles, and may be resin particles or organic-inorganic hybrid particles.

Examples of other materials for the insulating particles include polyolefin compounds, (meth)acrylate polymers, (meth)acrylate copolymers, block polymers, thermoplastic resins, cross-linked products of thermoplastic resins, thermal Hardening resin and water-soluble resin, etc. Only one type of material for the above-mentioned insulating particles may be used, or two or more types may be used in combination.

Examples of the polyolefin compound include polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, and the like. Examples of the (meth)acrylate polymer include polymethyl(meth)acrylate, polylauryl(meth)acrylate, polystearyl(meth)acrylate, and the like. Examples of the block polymer include polystyrene, styrene-acrylate copolymer, SB type styrene-butadiene block copolymer, and SBS type styrene-butadiene block copolymer, and Its hydrides, etc. Examples of the thermoplastic resin include ethylene polymers, ethylene copolymers, and the like. Examples of the thermosetting resin include epoxy resin, phenol resin, melamine resin, and the like. Examples of crosslinked products of the thermoplastic resin include the introduction of polyethylene glycol methacrylate, alkoxylated trimethylolpropane methacrylate, alkoxylated pentaerythritol methacrylate, and the like. Examples of the water-soluble resin include polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinylpyrrolidone, polyethylene oxide, methylcellulose, and the like. In addition, in order to adjust the degree of polymerization, a chain transfer agent can be used. Examples of chain transfer agents include mercaptans, carbon tetrachloride, and the like.

Examples of methods for arranging the insulating particles on the surface of the conductive part include chemical methods, physical or mechanical methods, and the like. Examples of the chemical method include interfacial polymerization, suspension polymerization in the presence of particles, and emulsion polymerization. Examples of the above physical or mechanical methods include spray drying, mixing, electrostatic adhesion, spraying, dipping, and vacuum evaporation. When electrically connecting electrodes, from the viewpoint of further effectively improving insulation reliability and conduction reliability, the method of arranging the insulating particles on the surface of the conductive part is preferably a physical method.

The outer surface of the conductive part and the outer surface of the insulating particles may each be covered with a compound having a reactive functional group. The outer surface of the conductive part and the outer surface of the insulating particles may not be directly chemically bonded, but may be indirectly chemically bonded through a compound having a reactive functional group. After the carboxyl groups are introduced to the outer surface of the conductive part, the carboxyl groups can be chemically bonded to the functional groups on the outer surface of the insulating particles through a polymer electrolyte such as polyethyleneimine.

The particle size of the above-mentioned insulating particles can be appropriately selected depending on the particle size of the conductive particles, the use of the conductive particles, and the like. The particle diameter of the above-mentioned insulating particles is preferably 10 nm or more, more preferably 100 nm or more, further preferably 300 nm or more, especially 500 nm or more, preferably 4000 nm or less, and more preferably 2000 nm or less. Furthermore, it is more preferably 1500 nm or less, particularly preferably 1000 nm or less. If the particle diameter of the insulating particles is more than the above lower limit, when the conductive particles are dispersed in the binder resin, the conductive layers in the plurality of conductive particles are less likely to come into contact with each other. If the particle diameter of the insulating particles is less than the above upper limit, there is no need to excessively increase the pressure or heat to a high temperature in order to eliminate the insulating particles between the electrodes and the conductive particles when connecting the electrodes.

The particle diameter of the insulating particles is preferably an average particle diameter, and more preferably a number average particle diameter. The particle diameter of the insulating particles is determined using a particle size distribution measuring device or the like. The particle diameter of the insulating particles is preferably determined by observing 50 arbitrary insulating particles with an electron microscope or an optical microscope and calculating an average value. When measuring the particle diameter of the insulating particles among the above-mentioned conductive particles, the measurement can be performed, for example, as follows.

Conductive particles were added to "Technovit 4000" manufactured by Kulzer Co., Ltd. so that the content became 30% by weight, and dispersed to prepare an embedded resin for conductive particle inspection. An ion milling device (“IM4000” manufactured by Hitachi High-Technologies, Inc.) was used to cut out a cross section of the conductive particles dispersed in the inspection embedding resin so as to pass through the vicinity of the center of the conductive particles dispersed in the embedding resin. Then, a field emission scanning electron microscope (FE-SEM) was used, the image magnification was set to 50,000 times, 50 conductive particles were randomly selected, and the insulating particles of each conductive particle were observed. The particle diameter of the insulating particles in each conductive particle was measured, and the arithmetic mean was calculated as the particle diameter of the insulating particles.

The ratio of the particle diameter of the conductive particles to the particle diameter of the insulating particles (particle diameter of the conductive particles/particle diameter of the insulating particles) is preferably 4 or more, more preferably 8 or more, and preferably 200 or less , preferably below 100. If the above ratio (particle diameter of conductive particles/particle diameter of insulating particles) is above the above lower limit and below the above upper limit, when electrically connecting electrodes, insulation reliability and conduction can be further effectively improved. reliability.

Soft magnetic body: The conductive particles preferably include a soft magnetic body portion disposed on the outer surface of the conductive portion. If the conductive particles include the soft magnetic part, the residual magnetization of the conductive particles can be further effectively reduced without impairing the conductivity of the conductive part. As a result, the connection resistance between the electrodes can be further effectively reduced, and magnetic aggregation can be further effectively suppressed. Furthermore, in this specification, the soft magnetic body part is defined as a part that is magnetized under the influence of an external magnetic field, but rapidly loses its magnetic force if the external magnetic field is removed. The soft magnetic body portion preferably has a saturation magnetization exceeding 0.00 A/m, and a ratio of residual magnetization to saturation magnetization (residual magnetization/saturation magnetization) of less than 0.3. The saturation magnetization of the soft magnetic body part and the above ratio (residual magnetization/saturation magnetization) can be measured according to the following procedure. A powder sample is prepared using the same material as that constituting the soft magnetic body part. This powder sample was measured using a vibration sample type magnetometer ("PV-300-5" manufactured by Toei Scientific Industries, Ltd.) in the same procedure as the measurement of residual magnetization and saturation magnetization of the conductive particles. Based on the obtained saturation magnetization and residual magnetization, the saturation magnetization of the soft magnetic body part and the above-mentioned ratio (residual magnetization/saturation magnetization) are obtained.

The soft magnetic body portion may be soft magnetic body particles or a soft magnetic body layer.

From the viewpoint of further effectively maintaining the connection resistance between the electrodes at a low level and further effectively suppressing magnetic aggregation, the conductive particles preferably include a plurality of the soft magnetic body portions. More specifically, the soft magnetic body part contains soft magnetic body particles, and preferably contains a plurality of soft magnetic body particles. As another specific aspect, the above-mentioned conductive particles are not covered with one soft magnetic body part and the entire outer surface of the conductive part is preferably in a state where the conductive part is exposed and a plurality of soft magnetic body parts are present in a spot pattern. Like. In the above-mentioned conductive particles, it is preferable that a plurality of the above-mentioned soft magnetic body parts are separately arranged on the outer surface of the above-mentioned conductive part. The number of separate soft magnetic body parts is preferably 2 or more, more preferably 3 or more, further preferably 5 or more, and particularly preferably 10 or more. The number of separate soft magnetic parts can be appropriately set based on the surface area of the conductive particles and the like.

The soft magnetic body portion is not particularly limited. Examples of materials for the soft magnetic body include: pure iron, silicon iron, nickel-iron alloy, Fe-Si-Al, iron-cobalt alloy, electromagnetic stainless steel, amorphous material (iron-based amorphous material and cobalt-based amorphous material, etc.) ), nanocrystals and ferrites (manganese-zinc ferrite, nickel-zinc ferrite, copper-zinc ferrite, cobalt ferrite, maghemite and magnetite, etc.), etc. Only one type of material may be used for the soft magnetic body part, or two or more types may be used in combination.

When the soft magnetic body part is particles, the particle size of the soft magnetic body part can be appropriately selected depending on the particle size of the conductive particles, the use of the conductive particles, and the like. The particle size of the soft magnetic part is preferably 5 nm or more, more preferably 10 nm or more, preferably 200 nm or less, and more preferably 100 nm or less. If the particle diameter of the soft magnetic part is equal to or greater than the lower limit, the connection resistance between the electrodes can be further effectively reduced, and magnetic aggregation can be further effectively suppressed.

The particle diameter of the soft magnetic part is preferably an average particle diameter, and more preferably a number average particle diameter. The particle diameter of the soft magnetic part is determined using a particle size distribution measuring device or the like. The particle diameter of the soft magnetic body portion is preferably determined by observing 50 arbitrary soft magnetic body portions with an electron microscope or an optical microscope and calculating an average value. When measuring the particle diameter of the soft magnetic part among the above-mentioned conductive particles, the measurement can be performed as follows, for example.

Conductive particles were added to "Technovit 4000" manufactured by Kulzer Co., Ltd. so that the content became 30% by weight, and dispersed to prepare an embedded resin for conductive particle inspection. An ion milling device (“IM4000” manufactured by Hitachi High-Technologies, Inc.) was used to cut out a cross section of the conductive particles dispersed in the inspection embedding resin so as to pass through the vicinity of the center of the conductive particles dispersed in the embedding resin. Then, a field emission scanning electron microscope (FE-SEM) was used, the image magnification was set to 50,000 times, 50 conductive particles were randomly selected, and the soft magnetic body part of each conductive particle was observed. The particle diameter of the soft magnetic part in each conductive particle was measured, and the arithmetic mean was calculated as the particle diameter of the soft magnetic part.

When the soft magnetic body portion is a layer, the thickness of the soft magnetic body portion can be appropriately selected depending on the particle size of the conductive particles, the use of the conductive particles, and the like. The thickness of the above-mentioned soft magnetic body part is preferably 5 nm or more, more preferably 10 nm or more, preferably 200 nm or less, and more preferably 100 nm or less.

The thickness of the soft magnetic body portion is preferably determined by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating an average value. In the case of measuring the thickness of the soft magnetic part in the above-mentioned conductive particles, the thickness can be measured as follows, for example.

Conductive particles were added to "Technovit 4000" manufactured by Kulzer Co., Ltd. so that the content became 30% by weight, and dispersed to prepare an embedded resin for conductive particle inspection. An ion milling device (“IM4000” manufactured by Hitachi High-Technologies, Inc.) was used to cut out a cross section of the conductive particles dispersed in the inspection embedding resin so as to pass through the vicinity of the center of the conductive particles dispersed in the embedding resin. Then, a field emission scanning electron microscope (FE-SEM) was used, the image magnification was set to 50,000 times, 50 conductive particles were randomly selected, and the thickness of the soft magnetic body portion of each conductive particle was observed. The thickness of the soft magnetic body part in each conductive particle was measured, and the arithmetic mean was calculated as the thickness of the soft magnetic body part.

From the viewpoint of further effectively suppressing magnetic aggregation, it is preferable that the conductive portion and the soft magnetic body portion are separated from each other. The distance between the above-mentioned conductive part and the above-mentioned soft magnetic body part is preferably 10 nm or more, more preferably 30 nm or more, further preferably 50 nm or more, preferably 800 nm or less, and more preferably 500 nm or less. If the above-mentioned separation distance is equal to or greater than the above-mentioned lower limit, the connection resistance between the electrodes can be further effectively reduced, and magnetic aggregation can be further effectively suppressed. Furthermore, regarding the distance between the above-mentioned conductive part and the above-mentioned soft magnetic body part, a field emission scanning electron microscope (FE-SEM) was used, the image magnification was set to 50,000 times, and 50 conductive particles were randomly selected. The distance between the conductive part and the soft magnetic part of each conductive particle was measured, and the arithmetic mean was calculated as the distance between the conductive part and the soft magnetic part. Furthermore, when the above-mentioned conductive particles include an insulating part disposed between the conductive part and the soft magnetic part, the thickness of the insulating part measured according to the following method for measuring the thickness of the insulating part may be used as the above-mentioned conductive part. The distance between the part and the above-mentioned soft magnetic body part.

The ratio of the area of the surface of the conductive part covered by the soft magnetic body part to the entire surface area of the conductive part (coverage rate of the soft magnetic body part) is preferably 5% or more, more preferably 10% or more, and more Preferably it is 20% or more, more preferably 30% or more, still more preferably 40% or more, particularly preferably 45% or more, most preferably 50% or more. The coverage rate of the above-mentioned soft magnetic body part may be 80% or less. If the coverage ratio of the soft magnetic body portion is equal to or higher than the lower limit, magnetic aggregation can be further effectively suppressed. From the viewpoint of further effectively maintaining the connection resistance between the electrodes at a low level, the coverage rate of the soft magnetic body portion may be 95% or less, 90% or less, 80% or less, or 70%. the following.

The coverage ratio of the soft magnetic body portion is determined as follows.

Observe the conductive particles from one direction with a scanning electron microscope (SEM). According to the total area of the soft magnetic body part within the circle of the outer peripheral part of the surface of the conductive part, it occupies the outer peripheral part of the surface of the conductive part in the observed image. Calculated as the ratio of a part of a circle to the entire area. The coverage rate of the soft magnetic body part is preferably calculated as an average coverage rate obtained by observing 20 conductive particles and averaging the measurement results of each conductive particle.

Insulation Department: It is preferable that the said conductive particle has an insulating part arrange|positioned between the said conductive part and the said soft magnetic body part. In the above-mentioned conductive particle, the above-mentioned soft magnetic body part is preferably arranged on the outer surface of the above-mentioned conductive part with the above-mentioned insulating part interposed. The soft magnetic body part is preferably not in contact with the conductive part. The insulating part is preferably disposed between the conductive part and the soft magnetic body part. If the conductive particles satisfy the above preferred aspect, the connection resistance between the electrodes can be further effectively reduced, and magnetic aggregation can be further effectively suppressed.

Furthermore, the above-mentioned insulating part is different from the above-mentioned insulating particles. The above-mentioned insulating particles are used to prevent short circuits between adjacent electrodes. The insulating part is used to prevent the soft magnetic body part from contacting the conductive part.

The above-mentioned insulating portion is not particularly limited as long as it is made of insulating material. Examples of the insulating portion include insulating resin and the like. Examples of the insulating portion include materials such as the insulating particles mentioned above.

The method of arranging the soft magnetic body part and the insulating part on the outer surface of the conductive part is not particularly limited. The method of arranging the soft magnetic body part and the insulating part on the outer surface of the conductive part can be used in the method of arranging the insulating particles on the surface of the conductive part. Specifically, as a method of arranging the soft magnetic body part and the insulating part on the outer surface of the conductive part, the following methods can be cited. After the surface of the soft magnetic body part is covered with the insulating part to obtain the soft magnetic body part covered with the insulating part, the method is to arrange the soft magnetic body part covered with the insulating part on the outer surface of the conductive part (in this case, The above-mentioned soft magnetic body part covered with the insulating part may be "FG beads" (registered trademark) manufactured by Tamagawa Seiki Co., Ltd., which is a form including a plurality of soft magnetic body parts). A method of arranging the soft magnetic body portion on the outer surface of the insulating portion-coated conductive particles after the insulating portion-coated conductive particles are obtained by coating the surface of the conductive portion with the insulating portion. After forming particles using the above-mentioned insulating part, arranging the above-mentioned soft magnetic body part on the surface of the particle to obtain particles with a soft magnetic body part, the particles with the soft magnetic body part are arranged outside the surface of the above-mentioned conductive part. Surface method.

The thickness of the insulating portion is preferably 10 nm or more, more preferably 30 nm or more, further preferably 50 nm or more, preferably 800 nm or less, and more preferably 500 nm or less. If the thickness of the insulating portion is equal to or greater than the lower limit, the connection resistance between the electrodes can be further effectively reduced, and magnetic aggregation can be further effectively suppressed. Furthermore, when the insulating part is a particle, the thickness of the insulating part is equivalent to the diameter of the particle.

The thickness of the insulating portion is preferably determined by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating an average value. In the case of measuring the thickness of the insulating portion in the above-mentioned conductive particles, the thickness can be measured as follows, for example.

Conductive particles were added to "Technovit 4000" manufactured by Kulzer Co., Ltd. so that the content became 30% by weight, and dispersed to prepare an embedded resin for conductive particle inspection. An ion milling device (“IM4000” manufactured by Hitachi High-Technologies, Inc.) was used to cut out a cross section of the conductive particles dispersed in the inspection embedding resin so as to pass through the vicinity of the center of the conductive particles dispersed in the embedding resin. Then, a field emission scanning electron microscope (FE-SEM) was used, the image magnification was set to 50,000 times, 50 conductive particles were randomly selected, and the thickness of the insulating portion of each conductive particle was observed. The thickness of the insulating part in each conductive particle was measured, and the arithmetic average was calculated as the thickness of the insulating part.

As a method of arranging the soft magnetic body portion and the insulating portion on the outer surface of the conductive portion, the following method is adopted: after the insulating portion covers the surface of the soft magnetic body portion to obtain the insulating portion-coated soft magnetic body portion, The insulating portion-coated soft magnetic body portion is disposed on the outer surface of the conductive portion; in the above case, the insulating portion-coated soft magnetic body portion is preferably an insulating layer-coated soft magnetic body particle. The above-mentioned insulating layer-coated soft magnetic particles are obtained by coating the surfaces of the soft magnetic particles with an insulating layer. That is, it is preferable to arrange the insulating layer-coated soft magnetic particles on the outer surface of the conductive portion. In this case, the average particle diameter of the insulating layer-coated soft magnetic particles is preferably 25 nm or more, more preferably 50 nm or more, preferably 800 nm or less, more preferably 500 nm or less, and further preferably 150 nm. nm or less. If the average particle diameter of the insulating layer-coated soft magnetic particles is more than the above lower limit, when the conductive particles are dispersed in the binder resin, the conductive layers in the plurality of conductive particles are less likely to come into contact with each other, and the resulting connected structure The insulation reliability is improved. If the average particle diameter of the insulating layer-coated soft magnetic particles is equal to or less than the upper limit, it is difficult to separate from the surface of the conductive particles, and magnetic aggregation can be effectively suppressed.

Furthermore, the average particle diameter of the soft magnetic particles covered with the insulating layer can be measured according to the following procedure, for example. Conductive particles were added to "Technovit 4000" manufactured by Kulzer Co., Ltd. so that the content became 30% by weight, and dispersed to prepare an embedded resin for conductive particle inspection. An ion milling device (“IM4000” manufactured by Hitachi High-Technologies, Inc.) was used to cut out a cross section of the conductive particles dispersed in the inspection embedding resin so as to pass through the vicinity of the center of the conductive particles dispersed in the embedding resin. Then, a field emission scanning electron microscope (FE-SEM) was used, the image magnification was set to 50,000 times, 50 conductive particles were randomly selected, and the insulating layer arranged on the outer surface of the conductive layer of each conductive particle was The particle size of the coated soft magnetic particles was observed. The particle diameter of the insulating layer-coated soft magnetic particles in each conductive particle was measured, and the arithmetic mean was calculated as the average particle diameter of the insulating layer-coated soft magnetic particles.

(conductive material) The conductive material of the present invention includes the above-mentioned conductive particles and a binder resin. The above-mentioned conductive particles are preferably dispersed in a binder resin and used, and preferably dispersed in a binder resin and used as a conductive material. The above-mentioned conductive material is preferably an anisotropic conductive material. The above conductive material is preferably used for electrical connection between electrodes. The above-mentioned conductive material is preferably a conductive material for circuit connection. Since the above-mentioned conductive particles are used in the above-mentioned conductive material, the insulation reliability and conduction reliability between electrodes can be further improved. In the above-mentioned conductive material, since the above-mentioned conductive particles are used, the connection resistance between electrodes can be further effectively reduced, and magnetic aggregation can be further effectively suppressed.

The above-mentioned binder resin is not particularly limited. As the binder resin, a known insulating resin is used. The above-mentioned binder resin preferably contains a thermoplastic component (thermoplastic compound) or a curable component, and more preferably contains a curable component. Examples of the curable component include photocurable components and thermosetting components. The photocurable component preferably contains a photocurable compound and a photopolymerization initiator. The thermosetting component preferably contains a thermosetting compound and a thermosetting agent.

Examples of the binder resin include vinyl resins, thermoplastic resins, curable resins, thermoplastic block copolymers, elastomers, and the like. Only one type of the above-mentioned binder resin may be used, or two or more types may be used in combination.

Examples of the vinyl resin include vinyl acetate resin, acrylic resin, styrene resin, and the like. Examples of the thermoplastic resin include polyolefin resin, ethylene-vinyl acetate copolymer, polyamide resin, and the like. Examples of the curable resin include epoxy resin, urethane resin, polyimide resin, unsaturated polyester resin, and the like. Furthermore, the curable resin may be a room temperature curing resin, a thermosetting resin, a light curing resin or a moisture curing resin. The above-mentioned curable resin can be used together with a curing agent. Examples of the thermoplastic block copolymer include styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, and styrene-butadiene-styrene. Hydrogenated products of block copolymers, and hydrogenated products of styrene-isoprene-styrene block copolymers, etc. Examples of the elastomer include styrene-butadiene copolymer rubber, acrylonitrile-styrene block copolymer rubber, and the like.

In addition to the above-mentioned conductive particles and the above-mentioned binder resin, the above-mentioned conductive material may contain, for example, fillers, extenders, softeners, plasticizers, polymerization catalysts, hardening catalysts, colorants, antioxidants, and heat stabilizers. , light stabilizers, UV absorbers, lubricants, antistatic agents and flame retardants and other additives.

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

The viscosity (η25) of the above-mentioned conductive material at 25°C is preferably 30 Pa·s or more, more preferably 50 Pa·s or more, preferably 400 Pa·s or less, and more preferably 300 Pa·s or less. If the viscosity (η25) is above the above lower limit and below the above upper limit, the insulation reliability between the electrodes can be further effectively improved, and the conduction reliability between the electrodes can be further effectively improved. The above-mentioned viscosity (η25) can be adjusted appropriately according to the types and amounts of the ingredients to be prepared.

The above-mentioned viscosity (η25) can be measured under the conditions of 25°C and 5 rpm using, for example, an E-type viscometer ("TVE22L" manufactured by Toki Industrial Co., Ltd.).

The conductive material of the present invention can be used as conductive paste, conductive film, etc. When the conductive material of the present invention is a conductive film, a film not containing conductive particles may be laminated on the conductive film containing conductive particles. The above-mentioned conductive paste is preferably an anisotropic conductive paste. The above-mentioned conductive film is preferably an anisotropic conductive film.

In 100% by weight of the above-mentioned conductive material, the content of the above-mentioned binder resin is preferably more than 10% by weight, more preferably more than 30% by weight, further preferably more than 50% by weight, particularly preferably more than 70% by weight, and more preferably 99.99% by weight or less, more preferably 99.9% by weight or less. If the content of the above-mentioned binder resin is above the above-mentioned lower limit and below the above-mentioned upper limit, the conductive particles are efficiently arranged between the electrodes, and the connection reliability of the connection object members connected by the conductive material can be further improved.

In 100% by weight of the above-mentioned conductive material, the content of the above-mentioned 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, and still more preferably 40% by weight or less, preferably 20% by weight or less, most preferably 10% by weight or less. If the content of the conductive particles is above the above lower limit and below the above upper limit, the conduction reliability and insulation reliability between electrodes can be further improved. If the content of the conductive particles is more than the above lower limit and less than the above upper limit, the connection resistance between the electrodes can be further effectively reduced, and magnetic aggregation can be further effectively suppressed.

(connection structure) The connection structure of the present invention includes: a first connection object member having a first electrode on its surface, a second connection object member having a second electrode on its surface, and a connecting portion connecting the first connection object member and the second connection object member. . In the connection structure of the present invention, the material of the connection part is the above-mentioned conductive particles, or a conductive material containing the above-mentioned conductive particles and a binder resin (the above-mentioned conductive material). In the connection structure of the present invention, the first electrode and the second electrode are electrically connected through the conductive portion in the conductive particles.

The above-mentioned connection structure can be obtained through the following steps: a step of arranging the above-mentioned conductive particles or the above-mentioned conductive material between the above-mentioned first connection object member and the above-mentioned second connection object member; and a step of conducting conductive connection by thermocompression bonding. . When the conductive particles include the insulating particles, it is preferable that the insulating particles are detached from the conductive particles during the thermocompression bonding.

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

The connection structure 81 shown in FIG. 7 includes a first connection target member 82, a second connection target member 83, and a connection portion 84 that connects the first connection target member 82 and the second connection target member 83. The connection portion 84 is formed of a conductive material containing the conductive particles 1 . The connection portion 84 is preferably formed by hardening a conductive material containing a plurality of conductive particles 1 . In addition, in FIG. 7 , for convenience of illustration, the conductive particles 1 are shown in a schematic form. Conductive particles 11, 21, 31, 41 or 51 can be used instead of conductive particles 1.

The first connection object member 82 has a plurality of first electrodes 82a on the surface (upper surface). The second connection object member 83 has a plurality of second electrodes 83a on the surface (lower surface). The first electrode 82a and the second electrode 83a are electrically connected by one or a plurality of conductive particles 1. Therefore, the first connection object member 82 and the second connection object member 83 are electrically connected through the conductive portion in the conductive particle 1 .

The manufacturing method of the above-mentioned connection structure is not particularly limited. An example of a method of manufacturing a connected structure includes a method of arranging the conductive material between a first connection target member and a second connection target member to obtain a laminated body, and then heating and pressurizing the laminated body. The pressure of the above-mentioned thermocompression bonding is preferably 40 MPa or more, more preferably 60 MPa or more, preferably 90 MPa or less, and more preferably 70 MPa or less. The heating temperature for the above-mentioned thermocompression bonding is preferably 80°C or higher, more preferably 100°C or higher, preferably 140°C or lower, and more preferably 120°C or lower. If the pressure and temperature of the thermocompression bonding are above the above lower limit and below the above upper limit, the conduction reliability between electrodes can be further improved. Furthermore, when the conductive particles include the insulating particles, the insulating particles can be easily detached from the surface of the conductive particles during conductive connection.

When the above-mentioned conductive particles include the above-mentioned insulating particles, when the above-mentioned laminate is heated and pressurized, the above-mentioned insulating properties existing between the above-mentioned conductive particles and the above-mentioned first electrode and the above-mentioned second electrode can be eliminated. particle. For example, during the heating and pressurization, the insulating particles present between the conductive particles and the first electrode and the second electrode are easily detached from the surfaces of the conductive particles. Furthermore, during the heating and pressurization, part of the insulating particles may be detached from the surface of the conductive particles, and the surface of the conductive part may be partially exposed. The exposed portion of the surface of the conductive portion is in contact with the first electrode and the second electrode, so that the first electrode and the second electrode can be electrically connected through the conductive particles.

The first connection object member and the second connection object member are not particularly limited. Specific examples of the first connection target member and the second connection target member include electronic components such as semiconductor wafers, semiconductor packages, LED (Light Emitting Diode) wafers, LED packages, capacitors, and diodes. , as well as electronic components such as resin films, printed circuit boards, flexible printed circuit boards, flexible flat cables, rigid flexible substrates, glass epoxy substrates, glass substrates and other circuit substrates. The first connection object member and the second connection object member are preferably electronic components.

Examples of electrodes provided on the connection object member include metals such as gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, copper electrodes, molybdenum electrodes, silver electrodes, SUS (Steel Use Stainless, Japanese stainless steel standard) electrodes, and tungsten electrodes. electrode. When the connection target member is a flexible printed circuit board, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, a silver electrode, or a copper electrode. When the connection object member is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode, a silver electrode or a tungsten electrode. In addition, when the above-mentioned electrode is an aluminum electrode, it may be an electrode formed only of aluminum, or it may be an electrode in which an aluminum layer is layered on the surface of the metal oxide layer. Examples of materials for the metal oxide layer include indium oxide doped with trivalent metal elements, zinc oxide doped with trivalent metal elements, and the like. Examples of the trivalent metal element include Sn, Al, Ga, and the like.

Hereinafter, Examples and Comparative Examples will be given to illustrate the present invention in detail. The present invention is not limited only to the following examples.

(Example 1) (1) Preparation of conductive particle body Prepare substrate particles having a particle size of 3 μm and made of a copolymer resin of tetramethylolmethane tetraacrylate and divinylbenzene. By using an ultrasonic disperser, 10 parts by weight of the substrate particles were dispersed in 100 parts by weight of an alkali solution containing 5% by weight of the palladium catalyst solution, and then the solution was filtered to take out the substrate particles. Next, the substrate particles were added to 100 parts by weight of a 1% by weight solution of dimethylamine borane to activate the surface of the substrate particles. After the surface-activated substrate particles are fully washed with water, 500 parts by weight of distilled water is added to disperse the particles to obtain a dispersion. Next, 1 part by weight of nickel particle slurry (average particle diameter: 100 nm) was added to the above-mentioned dispersion liquid for 3 minutes to obtain a suspension containing base material particles to which the core material was attached.

Also, prepare a nickel plating solution (pH 8.5) containing 0.35 mol/L nickel sulfate, 1.38 mol/L dimethylamine borane, and 0.5 mol/L sodium citrate.

While stirring the obtained suspension at 60° C., the above-mentioned nickel plating solution was slowly dropped into the suspension to perform electroless nickel plating. Thereafter, the suspension was filtered to remove the particles, washed with water and dried, thereby obtaining conductive particle bodies in which a nickel-boron conductive layer (thickness: 0.15 μm) was formed on the surface of the base particle.

(2) Preparation of soft magnetic particles covered with insulating layer The surface of the soft magnetic particles (soft magnetic part) is covered with an insulating layer (insulating part) as follows.

After placing the composition containing the following polymerizable compound into a 500 mL detachable flask equipped with a four-neck detachable lid, stirring blade, three-way stopcock, condenser tube and temperature probe, use an ultrasonic irradiation machine to Fully emulsified. Thereafter, the mixture was stirred at 200 rpm, and polymerization was performed for 5 hours at 50° C. in a nitrogen atmosphere. The above composition contains 200 parts by weight of distilled water, 5.2 parts by weight of iron oxide nanoparticles with a diameter of 30 nm (composition: maghemite or magnetite, manufactured by Sigma-Aldrich Company) and 0.1 parts by weight of 2,2' -Azobis{2-[N-(2-carboxyethyl)amidino]propane}. Furthermore, the above composition contains 0.1 parts by weight of polyoxyethylene lauryl ether ("Emulgen 106" manufactured by Kao Corporation), 1.7 parts by weight of methyl methacrylate, and 0.1 parts by weight of ethylene glycol dimethacrylate. After the reaction is completed, the reaction mixture is cooled, solid-liquid separation is performed twice with a centrifuge, and excess polymeric compounds are removed by washing to obtain insulating layer-coated soft magnetic particles whose entire surface is covered by the coating portion. (particle diameter 50 nm), and the coating portion is formed of a polymerizable compound.

Hereinafter, the obtained insulating layer-coated soft magnetic particles may be described as particles (A).

(3) Preparation of conductive particles (conductive particles with insulating layer-coated soft magnetic particles) The obtained particles (A) were dispersed in distilled water under ultrasonic irradiation to obtain a 10% by weight aqueous dispersion of the particles (A). Disperse 10 parts by weight of the obtained substrate particles with conductive portions on the surface (conductive particle bodies) in 100 parts by weight of distilled water, add 1 part by weight of a 10% by weight aqueous dispersion of particles (A), and stir at room temperature. Stir for 8 hours. After filtering through a 5 μm mesh filter, the particles were washed with methanol and dried to obtain conductive particles in which particles (A) were attached to the conductive particle body.

(4) Preparation of conductive materials (anisotropic conductive paste) 7 parts by weight of the obtained conductive particles, 25 parts by weight of bisphenol A type phenoxy resin, 4 parts by weight of quinoa type epoxy resin, 30 parts by weight of phenolic novolak type epoxy resin, and SI- 60L (manufactured by Sam Shin Chemical Industry Co., Ltd.), defoaming and stirring for 3 minutes to obtain a conductive material (anisotropic conductive paste).

(5) Preparation of connection structure Prepare a transparent glass substrate with an IZO (Indium Zinc Oxide) electrode pattern (first electrode, Vickers hardness of the metal on the electrode surface: 100 Hv) formed on the upper surface with L/S of 10 μm/10 μm. Furthermore, a semiconductor wafer was prepared on which an Au electrode pattern (second electrode, metal Vickers hardness of the electrode surface: 50 Hv) with L/S of 10 μm/10 μm was formed on the lower surface.

The obtained anisotropic conductive paste was coated on the above-mentioned transparent glass substrate to a thickness of 30 μm to form an anisotropic conductive paste layer. Next, the above-mentioned semiconductor wafer is stacked on the anisotropic conductive paste layer so that the electrodes face each other. Thereafter, while adjusting the temperature of the head so that the temperature of the anisotropic conductive paste layer reaches 100°C, place the pressure heating head on the upper surface of the semiconductor wafer and apply a pressure of 60 MPa to make the anisotropic conductive paste The layer was hardened at 100° C. to obtain a connected structure.

(Examples 2 to 7, 10 to 12 and Comparative Examples 3 and 4) The type of soft magnetic body part, the coverage ratio of the soft magnetic body part, the thickness of the insulating part, the amount of methyl methacrylate added when the surface of the soft magnetic body particle is covered with the insulating layer and Except for the average particle diameter of the particles (A), conductive particles, a conductive material, and a connected structure were obtained in the same manner as in Example 1.

Furthermore, in Example 10, nickel-iron alloy particles with an average particle size of 30 nm formed by a dry grinding device of a hammer mill or a ball mill were used instead of iron oxide nanoparticles. Furthermore, in Example 12, iron-cobalt alloy particles with an average particle diameter of 30 nm were used, which were molded from iron-cobalt alloy powder (manufactured by Daido Special Steel Co., Ltd.) using a dry grinding device of a hammer mill or a ball mill. Moreover, in Comparative Example 4, a nickel slurry with an average particle diameter of 30 nm was used. In addition, when the coverage rate of the soft magnetic part of Examples 2 to 7, 10 to 12 and Comparative Examples 3 and 4 was produced by coating the soft magnetic particles with an insulating layer, the particle (A) was changed to 10 Adjust according to the added amount of weight % aqueous dispersion.

(Example 8) (1) Preparation of conductive particle body Conductive particle bodies were produced in the same manner as in Example 1.

(2) Preparation of conductive particles covering the insulating part The surface of the conductive particle body is covered with an insulating layer (insulating part) as described below.

After placing the composition containing the following polymerizable compound into a 500 mL detachable flask equipped with a four-neck detachable lid, stirring blade, three-way stopcock, condenser tube and temperature probe, use an ultrasonic irradiation machine to Fully emulsified. Thereafter, the mixture was stirred at 200 rpm, and polymerization was performed for 5 hours at 50° C. in a nitrogen atmosphere. The above composition contains 200 parts by weight of distilled water, 20 parts by weight of the obtained conductive particle body, and 0.01 parts by weight of 2,2'-azobis{2-[N-(2-carboxyethyl)amidine group ]propane}. Furthermore, the above composition contains 0.1 part by weight of polyoxyethylene lauryl ether ("Emulgen 106" manufactured by Kao Corporation), 0.1 part by weight of methyl methacrylate, and 0.1 part by weight of ethylene glycol dimethacrylate. After the reaction is completed, it is cooled, solid-liquid separation is performed twice with a centrifuge, and excess polymerizable compounds are removed by washing to obtain insulating portion-coated conductive particles in which the entire surface of the conductive particle body is covered by the coating portion ( The thickness of the insulating layer is 50 nm), and the above-mentioned covering part is formed of a polymeric compound.

(3) Production of conductive particles (conductive particles with an insulating layer and soft magnetic particles) The surface of the insulating layer in the conductive particles is covered with the insulating portion by coating the soft magnetic particles (soft magnetic portion) with the insulating portion as described below.

Iron oxide nanoparticles with a diameter of 30 nm (composition: maghemite or magnetite, manufactured by Sigma-Aldrich Company) were dispersed in distilled water under ultrasonic irradiation to obtain a 10% by weight aqueous dispersion. 10 parts by weight of the obtained insulating portion-coated conductive particles were dispersed in 100 parts by weight of distilled water, 1 part by weight of a 10% by weight aqueous dispersion of iron oxide nanoparticles was added, and the mixture was stirred at room temperature for 8 hours. After filtering through a 5 μm mesh filter, washing with methanol and drying, conductive particles (having an insulating layer and soft magnetic properties) with iron oxide nanoparticles attached to the insulating portion-coated conductive particles are obtained. conductive particles (bulk particles).

(4) Preparation of conductive materials (anisotropic conductive paste) Except using the obtained electroconductive particle, it carried out similarly to Example 1, and obtained the electroconductive material.

(5) Preparation of connection structure Except using the obtained conductive material, it carried out similarly to Example 1, and obtained the connection structure.

(Example 9) (1) Preparation of conductive particle body Conductive particle bodies were produced in the same manner as in Example 1.

(2) Preparation of soft magnetic particles coated with insulating particles Insulating particles are formed as follows.

Put the composition containing the following polymerizable compound into a 500 mL detachable flask equipped with a four-neck detachable lid, stirring blade, three-way stopcock, condenser tube and temperature probe, and stir at 200 rpm. Polymerization was performed for 5 hours under a nitrogen atmosphere at 50°C. The above composition contains 200 parts by weight of distilled water, 0.2 parts by weight of acidic phosphoryloxy polyoxyethylene glycol methacrylate, and 0.2 parts by weight of 2,2'-azobis{2-[N-(2- Carboxyethyl) amidino] propane}, 20 parts by weight of methyl methacrylate and 1 part by weight of ethylene glycol dimethacrylate. After the reaction is completed, the mixture is cooled, solid-liquid separation is performed twice with a centrifuge, and excess polymerizable compounds are removed by washing to obtain insulating particles (particle diameter 300 nm).

The surface of the obtained insulating particles is coated with soft magnetic particles (soft magnetic part) as follows.

Iron oxide nanoparticles with a diameter of 30 nm (composition: maghemite or magnetite, manufactured by Sigma-Aldrich Company) were dispersed in distilled water under ultrasonic irradiation to obtain a 10% by weight aqueous dispersion. 10 parts by weight of the obtained insulating particles were dispersed in 100 parts by weight of distilled water, 1 part by weight of a 10% by weight aqueous dispersion of iron oxide nanoparticles was added, and the mixture was stirred at room temperature for 8 hours. After filtering through a 5 μm mesh filter, washing with methanol, and drying, soft magnetic particle-coated insulating particles with iron oxide nanoparticles attached to the insulating particles are obtained.

(3) Production of conductive particles (conductive particles with soft magnetic particles coated with insulating particles) The surface of the conductive particle body is coated with soft magnetic particles and insulating particles are coated as follows.

The obtained soft magnetic particle-coated insulating particles were dispersed in distilled water under ultrasonic irradiation to obtain a 10% by weight aqueous dispersion. Disperse 10 parts by weight of the conductive particles in 100 parts by weight of distilled water, add 1 part by weight of a 10% by weight aqueous dispersion of soft magnetic particles covering the insulating particles, and stir at room temperature for 8 hours. After filtering through a 5 μm mesh filter, washing with methanol, and drying, the conductive particles (soft magnetic particles with soft magnetic particles) coated with insulating particles attached to the conductive particle body are obtained. Conductive particles coated with insulating particles).

(4) Preparation of conductive materials (anisotropic conductive paste) Except using the obtained electroconductive particle, it carried out similarly to Example 1, and obtained the electroconductive material.

(5) Preparation of connection structure The obtained conductive material was used, except that it carried out similarly to Example 1, and obtained the connection structure.

(Comparative example 1) The conductive particle body of Example 1 was prepared as the conductive particle. Except using this conductive particle, it carried out similarly to Example 1, and obtained the conductive material and the connection structure.

(Comparative example 2) (1) Preparation of conductive particle body The conductive particle body was produced in the same manner as in Example 1.

(2) Preparation of conductive particles (soft magnetic particles coated conductive particles) The surface of the conductive particle body is coated with soft magnetic particles as described below.

Iron oxide nanoparticles with a diameter of 30 nm (composition: maghemite or magnetite, manufactured by Sigma-Aldrich Company) were dispersed in distilled water under ultrasonic irradiation to obtain a 10% by weight aqueous dispersion. Disperse 10 parts by weight of the conductive particles in 100 parts by weight of distilled water, add 1 part by weight of a 10% by weight aqueous dispersion of iron oxide nanoparticles, and stir at room temperature for 8 hours. After filtering through a 5 μm mesh filter, washing with methanol, and drying, soft magnetic particle-coated conductive particles with iron oxide nanoparticles attached to the conductive particle body are obtained.

(3) Preparation of conductive materials (anisotropic conductive paste) Except using the obtained electroconductive particle, it carried out similarly to Example 1, and obtained the electroconductive material.

(4) Preparation of connection structure The obtained conductive material was used, except that it carried out similarly to Example 1, and obtained the connection structure.

(evaluate) (1) Residual magnetization and saturation magnetization of conductive particles Calibration of the vibration sample type magnetometer ("PV-300-5" manufactured by Toei Scientific Industry Co., Ltd.) was performed using a capsule filled with nickel powder as a calibration sample of the device. The obtained conductive particles were weighed in a capsule and mounted in a sample holder. The sample holder was placed on the magnetometer body, and the magnetization curve was obtained by measuring under the conditions of a temperature of 20°C (constant temperature), a maximum applied magnetic field of 20 kOe, and a speed of 3 min/loop. The residual magnetization and saturation magnetization of the conductive particles were determined based on the obtained magnetization curve.

Furthermore, the ratio of residual magnetization to saturation magnetization (residual magnetization/saturation magnetization) was calculated based on the measurement results.

(2) Coverage rate of soft magnetic body The ratio of the area of the portion of the surface of the conductive portion of the obtained conductive particles covered with the soft magnetic body portion to the entire surface area of the conductive portion (coverage rate of the soft magnetic body portion) was measured.

The coverage ratio of the soft magnetic body portion is determined as follows.

The conductive particles obtained by observing from one direction with a scanning electron microscope (SEM) are calculated based on the total area of the soft magnetic body part within the circle of the outer peripheral part of the surface of the conductive part occupying the surface of the conductive part in the observed image. It is calculated as the ratio of the entire area within the circle of the outer peripheral part. The coverage rate of the soft magnetic body portion was calculated as an average coverage rate obtained by observing 20 conductive particles and averaging the measurement results of each conductive particle.

(3)Thickness of insulating part The thickness of the insulating portion of the obtained conductive particles was measured as follows.

The obtained conductive particles were added to "Technovit 4000" manufactured by Kulzer Corporation so that the content became 30% by weight, and were dispersed to prepare an embedded resin for conductive particle inspection. An ion milling device (“IM4000” manufactured by Hitachi High-Technologies, Inc.) was used to cut out a cross section of the conductive particles dispersed in the inspection embedding resin so as to pass through the vicinity of the center of the conductive particles dispersed in the embedding resin. Then, a field emission scanning electron microscope (FE-SEM) was used, the image magnification was set to 50,000 times, 50 conductive particles were randomly selected, and the thickness of the insulating portion of each conductive particle was observed. The thickness of the insulating part in each conductive particle was measured, and the arithmetic average was calculated as the thickness of the insulating part.

(4) Magnetic aggregation of conductive particles The obtained conductive material was observed to confirm whether magnetic aggregation of conductive particles occurred. The magnetic aggregation of the conductive particles was judged based on the following conditions.

[Criteria for judging magnetic aggregation of conductive particles] ○○: No magnetic aggregation of conductive particles will occur ○: Magnetic aggregation of conductive particles slightly occurs, but the inhibitory effect is confirmed ×: Generating magnetic aggregation of conductive particles

(5)Connect resistance (between upper and lower electrodes) The connection resistance between the upper and lower electrodes of the 20 obtained connection structures was measured by the four-terminal method. Furthermore, the connection resistance can be obtained by measuring the voltage when a certain current flows according to the relationship of voltage = current × resistance. Determine the connection resistance based on the following criteria.

[Judgment criteria for connection resistance] ○○○: The connection resistance is 1.5 Ω or less ○○: Connection resistance exceeds 1.5 Ω and is 2.0 Ω or less ○: Connection resistance exceeds 2.0 Ω and is less than 5.0 Ω △: Connection resistance exceeds 5.0 Ω and is less than 10 Ω ×: Connection resistance exceeds 10 Ω

(6) Insulation reliability (between horizontally adjacent electrodes) Among the 20 connected structures obtained in the evaluation of conduction reliability in the above (5), the presence or absence of leakage between adjacent electrodes was evaluated by measuring the resistance value using a testing machine. Insulation reliability is evaluated based on the following standards.

[Judgment criteria for insulation reliability] ○○○: The number of connection structures with a resistance value of 10 ⁸ Ω or more is 20 ○○: The number of connection structures with a resistance value of 10 ⁸ Ω or more is 18 or more And less than 20 ○: The number of connection structures with a resistance value of 10 ⁸ Ω or more is 15 or more and less than 18 △: The number of connection structures with a resistance value of 10 ⁸ Ω or more is 10 or more And less than 15 ×: The number of connected structures with a resistance value of 10 ⁸ Ω or more does not reach 10

Details and results are shown in Tables 1 and 2 below.

[Table 1]

[Table 2]

In the conductive particles obtained in Examples 1 to 12, magnetic aggregation of the conductive particles was suppressed compared to the conductive particles obtained in Comparative Examples 1 to 4.

Furthermore, the conductive particles obtained in Examples 1 to 7 and 10 to 12 showed lower connection resistance than the conductive particles obtained in Example 8. The reason is considered to be that in the conductive particles obtained in Example 8, the entire surface of the conductive particle body was covered with the insulating portion, so the conductive layer was less exposed. In contrast, in Examples 1 to 7 and 10 The conductive particles obtained in step 12 are covered with the insulating layer-coated soft magnetic particles, so the conductive layer is mostly exposed.

Furthermore, the conductive particles obtained in Examples 1 to 7 and 10 to 12 showed lower connection resistance than the conductive particles obtained in Example 9. The reason is considered to be that in the conductive particles of Example 9, the soft magnetic particles, in which iron oxide nanoparticles with an average particle diameter of 30 nm are attached to insulating particles with an average particle diameter of 300 nm, coat the insulating particles. Compared to the conductive particles of Examples 1 to 7 and 10 to 12, the average particle diameter of the insulating layer-coated soft magnetic particles is relatively small (average particle diameter exceeding 300 nm). nm ~ 130 nm average particle size). Therefore, in the conductive particles of Example 9, the insulating particles are not easily detached from the surface of the conductive particles during the thermocompression bonding during the production of the connected structure. In contrast, in the conductive particles of Examples 1 to 7 and 10 to 12 Among the conductive particles, the insulating layer-coated soft magnetic particles are easily detached from the surface of the conductive particles.

1: Conductive particles 2:Substrate particles 3: Conductive part 11: Conductive particles 12: Soft magnetic body 13: Insulating particles 21: Conductive particles 22:Insulation Department 31: Conductive particles 32:Insulation Department 41: Conductive particles 42:Insulation Department 51: Conductive particles 52:Insulation Department 61: Conductive Department 62: Core material 63:Protrusion 81:Connection structure 82: The first connection object member 82a: 1st electrode 83: The second connection object member 83a: 2nd electrode 84:Connection Department

FIG. 1 is a cross-sectional view showing conductive particles according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing conductive particles according to the second embodiment of the present invention. FIG. 3 is a cross-sectional view showing conductive particles according to the third embodiment of the present invention. FIG. 4 is a cross-sectional view showing conductive particles according to the fourth embodiment of the present invention. FIG. 5 is a cross-sectional view showing conductive particles according to the fifth embodiment of the present invention. FIG. 6 is a cross-sectional view showing conductive particles according to the sixth embodiment of the present invention. 7 is a cross-sectional view schematically showing a connected structure using conductive particles according to the first embodiment of the present invention.

Claims (10)

Conductive particles comprising base particles and a conductive portion disposed on the surface of the base particles, the ratio of the residual magnetization of the conductive particles to the saturation magnetization of the conductive particles is 0.6 or less, and the conductive particles have the above Residual magnetization is 0.01A/m or less. The conductive particle according to claim 1, which includes a soft magnetic body portion arranged on the outer surface of the conductive portion. The conductive particle according to claim 2, further comprising an insulating part disposed between the conductive part and the soft magnetic part, and the soft magnetic part being disposed on the outer surface of the conductive part with the insulating part interposed therebetween. The conductive particle according to claim 3, wherein the distance between the conductive part and the soft magnetic part is 10 nm or more and 500 nm or less. The conductive particle according to Claim 2 is provided with a plurality of the soft magnetic body parts, and the plurality of the soft magnetic body parts are separately arranged on the outer surface of the conductive part. The conductive particle according to Claim 2, wherein the area of the portion of the surface of the conductive portion covered by the soft magnetic body portion accounts for more than 30% of the entire surface area of the conductive portion. The conductive particle according to Claim 6, wherein the area of the portion of the surface of the conductive portion covered by the soft magnetic body portion accounts for more than 40% of the entire surface area of the conductive portion. The conductive particles of claim 1 or 2 include a plurality of insulating particles arranged on the outer surface of the conductive part. A conductive material containing the conductive particles of claim 1 or 2 and a binder resin. A connection structure provided with: a first connection object member having a first electrode on its surface, a second connection object member having a second electrode on its surface, and a connection connecting the first connection object member and the second connection object member. part; and the material of the above-mentioned connecting part is the conductive particles according to any one of claims 1 to 8, or a conductive material containing the above-mentioned conductive particles and a binder resin, and the above-mentioned first electrode and the above-mentioned second electrode are formed by the above-mentioned The above-mentioned conductive parts in the conductive particles are electrically connected.