TW202015074A - Conductive particles, conductive material, and connecting structure - Google Patents

Abstract

Provided are conductive particles capable of effectively reducing connection resistance between electrodes and effectively suppressing magnetic aggregation. The conductive particles each comprise a substrate particle and a conductive part disposed on the surface of the substrate particle, and the proportion of residual magnetization to saturation magnetization is 0.6 or less.

Description

Conductive particles, conductive materials and connection structure

The present invention relates to a conductive particle in which a conductive part is arranged on the surface of a base particle. In addition, the present invention relates to a conductive material and a connecting structure using the conductive particles.

Anisotropic conductive materials such as anisotropic conductive paste and anisotropic conductive film are widely known. In the anisotropic conductive material, conductive particles are dispersed in the binder resin. In addition, as the conductive particles, conductive particles that have been subjected to insulation treatment on the surface of the conductive layer are sometimes used.

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

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

[Patent Document 1] Japanese Patent Laid-Open No. 2013-258138

[Problems to be solved by the invention]

In the above Patent Document 1, the saturation magnetization of the mother particles is 45 emu/cm ³ or less. However, Patent Document 1 is limited to describing that saturation magnetization is controlled within a specific range, and there is no description about residual magnetization at all.

Conventional conductive particles have a conductive metal such as nickel on the surface by plating or the like, and are used for electrical connection between electrodes. In addition, in the previous conductive particles, there is a case where metals such as nickel having magnetism are magnetized due to the surrounding environment, manufacturing steps, etc., and the conductive particles are aggregated (magnetically aggregated). As a method for solving the above-mentioned problems, as described in Patent Document 1 and the like, a method in which the plating layer contains phosphorus to reduce saturation magnetization and the like can be cited. However, there are cases where the phosphorus content of the plating layer becomes higher, the resistance value of the conductive particles increases significantly, and if the conductive particles are used to electrically connect between the electrodes, the connection resistance between the electrodes also becomes higher .

In addition, in the previous conductive particles, although the saturation magnetization can be reduced, it is difficult to sufficiently reduce the residual magnetization. In order to suppress the magnetic aggregation of conductive particles, not only the saturation magnetization but also the residual magnetization must be reduced. In the previous conductive particles, it was difficult to achieve both the reduction of the connection resistance between the electrodes and the 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 can effectively suppress magnetic aggregation. In addition, an object of the present invention is to provide a conductive material and a connection structure using the above conductive particles. [Technical means to solve the problem]

According to a broad aspect of the present invention, there is provided a conductive particle including a base particle and a conductive portion disposed on the surface of the base particle, and a 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 above-mentioned residual magnetization is 0.02 A/m or less.

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

In a specific aspect of the conductive particle of the present invention, it includes an insulating portion disposed between the conductive portion and the soft magnetic body portion, and the soft magnetic body portion is disposed on the conductive portion via the insulating portion On the outer surface.

In a specific aspect of the conductive particles of the present invention, the distance between the conductive portion and the soft magnetic body portion 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 the 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 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.

In a specific aspect of the conductive particles of the present invention, the area 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.

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 portion.

According to a broad aspect of the present invention, there is provided a conductive material containing the above 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 a surface, a second connection object member having a second electrode on a surface, and the first connection object member The connection portion of the second connection object member; and the material of the connection portion is the conductive particles, or a conductive material containing the conductive particles and the binder resin, the first electrode and the second electrode pass the conductivity The conductive parts in the particles are electrically connected. [Effect of invention]

The conductive particles of the present invention include base particles and a conductive portion disposed on the surface 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 configuration, the connection resistance between the electrodes can be effectively reduced, and the magnetic aggregation can be effectively suppressed.

The details of the present invention will be described below.

(Conductive particles) The conductive particles of the present invention include base particles and a conductive portion disposed on the surface 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 configuration, the connection resistance between the electrodes can be effectively reduced, and the magnetic aggregation can be effectively suppressed.

In the conventional conductive particles, there are cases where metals such as nickel with magnetism are magnetized due to the surrounding environment or manufacturing steps, etc., and the conductive particles are aggregated (magnetically aggregated). As a method of suppressing the aggregation (magnetic agglomeration) of the conductive particles, a method of reducing the saturation magnetization by containing phosphorus in the plating layer can be mentioned. However, there are cases where the phosphorus content of the plating layer becomes higher, the resistance value of the conductive particles increases significantly, and if the conductive particles are used to electrically connect between the electrodes, the connection resistance between the electrodes also becomes higher .

In addition, in the previous 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 the previous conductive particles, it was difficult to balance both the reduction of the connection resistance between the electrodes and the suppression of magnetic aggregation.

The present inventors have found that by using specific conductive particles, it is possible to reduce both the connection resistance between the electrodes and suppress the magnetic aggregation of the conductive particles. In the present invention, since the above-mentioned configuration is provided, the connection resistance between the electrodes can be effectively reduced, and the magnetic aggregation of conductive particles can be effectively suppressed.

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

From the viewpoint of effectively reducing the connection resistance between the 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 above 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 the electrodes and further effectively suppressing magnetic aggregation, the closer the above ratio (residual magnetization/saturation magnetization) to 0.0, the better. If the above ratio (residual magnetization/saturation magnetization) is equal to or lower than the above upper limit, the connection resistance between the electrodes can be further effectively reduced, and the magnetic aggregation can be further effectively suppressed. In addition, the lower limit of the above ratio (residual magnetization/saturation magnetization) is not particularly limited. The above ratio (residual magnetization/saturation magnetization) is preferably, for example, 0.001 or more, and 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 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, and further 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 above-mentioned residual magnetization is to 0.0000 A/m (0.0 emu/cm ³ ), the better. If the residual 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 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 by, for example, adjusting the coverage rate of the soft magnetic body part described below. For example, if the coverage rate of the soft magnetic body portion is increased, the above-mentioned residual magnetization can be reduced, and if the coverage rate 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 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, and further preferably 0.05 A/m (50 emu/cm ³ ) the following. If the saturation magnetization is equal to or less than the upper limit, the magnetic aggregation can be further effectively suppressed. From the viewpoint of magnetic force collection, the saturation magnetization of the conductive particles is preferably 0.001 A/m (1 emu/cm ³ ) or more. The 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, and still more preferably 0.015 A/m (15 emu/cm ³ ) the above. If the saturation magnetization is equal to or greater than the above lower limit, the conductive particles in the anisotropic conductive material can be efficiently arranged by the external magnetic field.

The saturation magnetization of the conductive particles can be controlled by, for example, adjusting the thickness of the conductive layer or the conductive portion. For example, if the thickness of the conductive layer or the conductive portion is increased, the saturation magnetization can be increased, and if the thickness of the conductive layer or the conductive portion is thinned, the saturation magnetization can be reduced.

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

Use the capsule enclosed with nickel powder as the calibration sample of the device to perform the calibration of the vibration sample type magnetometer. Secondly, the conductive particles are weighed in the capsule and installed in the sample holder. The sample holder was set on the magnetometer body, and the measurement was performed 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, thereby obtaining a magnetization curve. The residual magnetization and saturation magnetization (A/m) were obtained from the obtained magnetization curve.

The particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 100 μm or less, more preferably 60 μm or less, more preferably 30 μm or less, and more preferably 10 μm or less, Especially preferred is less than 5 μm. If the particle diameter of the conductive particles is more than the lower limit and less than the upper limit, when the conductive particles are used to connect the electrodes, the contact area between the conductive particles and the electrode becomes sufficiently large, and the It is difficult to form agglomerated conductive particles. In addition, the distance between the electrodes connected by the conductive particles is not too large, and the conductive portion is difficult to peel from the surface of the base particles.

The particle diameter of the conductive particles is preferably an average particle diameter, more preferably a number average particle diameter. The particle diameter of the conductive particles can be obtained by, for example, observing any 50 conductive particles by an electron microscope or an optical microscope, calculating the average particle diameter of each conductive particle, or performing laser diffraction particle size distribution Determination. In observation by an electron microscope or an optical microscope, the particle diameter of each conductive particle is obtained as the particle diameter in terms of a circle-equivalent diameter. In observation by an electron microscope or an optical microscope, the average particle diameter of the circular equivalent diameter of any 50 conductive particles is approximately equal to the average particle diameter of the spherical equivalent diameter. In the laser diffraction-type particle size distribution measurement, the particle diameter of each conductive particle is obtained as the particle diameter in terms of the spherical equivalent diameter. The particle diameter 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 coefficient of variation of the particle diameter of the conductive particles is below the upper limit, the conduction reliability and insulation reliability between the 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 the particle size of conductive particles Dn: average particle diameter of conductive particles

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

Hereinafter, a specific embodiment of the present invention will be described with reference to the drawings.

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

The conductive particles 1 shown in FIG. 1 include base particles 2 and conductive portions 3. In the conductive particles 1, the conductive portion 3 is a conductive layer. The conductive portion 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 portion 3. The conductive particles 1 have a conductive portion 3 on the surface. In the conductive particles 1, the conductive portion 3 is a single-layer conductive portion (conductive layer). In the conductive particles, the conductive portion may cover the entire surface of the base particles, and the conductive portion may cover a part of the surface of the base particles. In the conductive particles, the conductive portion may be a single-layer conductive portion or a multilayer conductive portion including two or more layers.

Unlike the conductive particles 51 described below, the conductive particles 1 do not have a core substance. The conductive particles 1 do not have protrusions on the conductive surface, and do not have protrusions on the outer surface of the conductive portion 3. The conductive particles 1 are spherical. However, the conductive particles 1 may have a core substance, may have protrusions on the conductive surface, or may have protrusions on the outer surface of the conductive portion 3.

The conductive particles may not have protrusions on the conductive surface, and may not have protrusions on the surface other than the conductive portion, or may be spherical. In addition, the conductive particles 1 are different from the conductive particles 11, 21, 41, and 51 described below, and do not have insulating particles. However, the conductive particles 1 may have insulating particles arranged on the outer surface of the conductive portion 3.

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

The conductive particle 11 shown in FIG. 2 includes the base particle 2, the conductive portion 3, the soft magnetic body portion 12, and the insulating particle 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 portion 12 and insulating particles 13. The conductive particles 11 include insulating particles 13 that are not in contact with the soft magnetic body portion 12.

The conductive particles may or may not have a soft magnetic body portion. The conductive particles may or may not have insulating particles. In the conductive particles, the soft magnetic body portion is preferably arranged on the outer surface of the conductive portion. The soft magnetic body portion is preferably not in contact with the conductive portion. Among the conductive particles, the insulating particles are preferably arranged on the outer surface of the conductive portion.

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

The conductive particle 21 shown in FIG. 3 includes the base particle 2, the conductive portion 3, the soft magnetic body portion 12, and the insulating particle 13.

Unlike the conductive particles 11, the conductive particles 21 have an insulating portion 22 that covers 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 portion 12. The conductive particles 21 include insulating particles 13 that are not in contact with the insulating portion 22.

The insulating portion 22 is 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 arranged between the conductive portion 3 and the soft magnetic body portion 12. The soft magnetic body portion 12 does not contact the conductive portion 3. The insulating portion only needs to cover at least a part of the surface of the soft magnetic body portion, and may not cover the entire surface of the soft magnetic body portion. In the conductive particles, the soft magnetic body portion is preferably arranged on the outer surface of the conductive portion. The soft magnetic body portion is preferably arranged on the outer surface of the conductive portion via the insulating portion. The insulating portion is preferably arranged between the conductive portion and the soft magnetic body portion. The conductive particles may have insulating particles, or may not have insulating particles.

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

The conductive particle 31 shown in FIG. 4 includes the base particle 2, the conductive portion 3, and the soft magnetic body portion 12.

The conductive particles 31 differ from the conductive particles 11 and have an insulating portion 32 covering the surface of the conductive portion 3.

The insulating portion 32 is an insulating material. In the conductive particles 31, the insulating portion 32 covers the entire surface of the conductive portion 3. Therefore, the insulating portion 32 is arranged between the conductive portion 3 and the soft magnetic body portion 12. The soft magnetic body portion 12 does not contact the conductive portion 3. The insulating portion only needs to cover at least a part of the surface of the conductive portion, and may not cover the entire surface of the conductive portion. In the conductive particles, the soft magnetic body portion is preferably arranged on the outer surface of the conductive portion via the insulating portion. The insulating portion is preferably arranged between the conductive portion and the soft magnetic body portion. The conductive particles may have insulating particles arranged on the outer surface of the conductive portion.

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

The conductive particles 41 shown in FIG. 5 include base particles 2, conductive portions 3, soft magnetic body portions 12, and insulating particles 13.

The conductive particle 41 is different from the conductive particle 11 and has an insulating portion 42 arranged on the outer surface of the conductive portion 3. The conductive particles 41 include insulating particles 13 that are not in contact with the soft magnetic body portion 12. The conductive particles 41 include insulating particles 13 that are not in contact with the insulating portion 42.

The insulating portion 42 is an insulating material. In the conductive particles 41, the insulating portion 42 is insulating particles. In the conductive particles 41, the insulating portion 42 is disposed on the outer surface of the conductive portion 3, and the soft magnetic body portion 12 is disposed on the outer surface of the insulating portion 42. Therefore, the insulating portion 42 is arranged between the conductive portion 3 and the soft magnetic body portion 12. The soft magnetic body portion 12 does not contact the conductive portion 3. The insulating portion only needs to cover at least a part of the surface of the conductive portion, and may not cover the entire surface of the conductive portion. In the conductive particles, the soft magnetic body portion is preferably arranged on the outer surface of the conductive portion via the insulating portion. The insulating portion is preferably arranged between the conductive portion and the soft magnetic body portion. The conductive particles may have insulating particles, or may not have insulating particles.

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

The conductive particle 51 shown in FIG. 6 includes the base particle 2, the conductive portion 61, the soft magnetic body portion 12, and the insulating particle 13.

Unlike the conductive particles 21, the conductive particles 51 have a plurality of core substances 62 arranged on the surface of the base particles 2. The conductive portion 61 covers the base particle 2 and the core substance 62. By covering the core material 62 with the conductive portion 61, the conductive particles 51 have a plurality of protrusions 63 on the surface. In the conductive particles 51, due to the core material 62, the surface of the conductive portion 61 is raised, and a plurality of protrusions 63 are formed. In the conductive particles, in order to form the protrusions, the core material may be used, or the core material may not be used. The above-mentioned conductive particles may not have the above-mentioned core substance.

Hereinafter, 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 mixed particles, and metal particles. The substrate particles are preferably substrate particles other than metal particles, and more preferably resin particles, inorganic particles other than metal particles, or organic-inorganic mixed particles. The substrate particles may be core-shell particles having 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 resin particles, various organic substances can be suitably used. Examples of the material of the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene and polybutadiene; polymethyl methacrylate and Acrylic resins such as polymethyl acrylate; polycarbonate, polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea Resins, epoxy resins, unsaturated polyester resins, saturated polyester resins, polyethylene terephthalate, polyphenols, polyphenylene ethers, polyacetals, polyimides, polyimides, polyimides, poly Ether ether ketone, polyether ballast, divinylbenzene polymer and divinylbenzene copolymer etc. Examples of the divinylbenzene-based copolymer include divinylbenzene-styrene copolymer and divinylbenzene-(meth)acrylate copolymer. Since the hardness of the above resin particles can be easily controlled within an appropriate range, the material of the above resin particles is preferably polymerized by polymerizing one or more polymerizable monomers having ethylenically unsaturated groups Thing.

When the polymerizable monomer having an ethylenically unsaturated group can be polymerized to obtain the above-mentioned resin particles, examples of the polymerizable monomer having an ethylenically unsaturated group include non-crosslinkable monomers and crosslinkability. monomer.

Examples of the above non-crosslinkable monomers include styrene monomers such as styrene and α-methylstyrene; carboxyl group-containing ones 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, (methyl ) Lauryl acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, and (meth) acrylate alkyl esters (meth) acrylate, etc. Compound; 2-hydroxyethyl (meth)acrylate, glyceryl (meth)acrylate, polyoxyethylene (meth)acrylate, glycidyl (meth)acrylate and other oxygen-containing (meth)acrylates 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 compounds such as vinyl stearate; unsaturated hydrocarbons such as ethylene, propylene, isoprene and butadiene; trifluoromethyl (meth)acrylate, pentafluoroethyl (meth)acrylate, chlorine Halogen-containing monomers such as ethylene, vinyl fluoride and chlorostyrene.

Examples of the crosslinkable monomers 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, glycerol tri(meth)acrylate, glycerol 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-butane Multifunctional (meth)acrylate compounds such as diol di(meth)acrylate; (iso) triallyl cyanurate, triallyl trimellitate, divinylbenzene, diallyl phthalate Ester, diallyl acrylamide, diallyl ether, and γ-(meth)acryl propyl propyl trimethoxy silane, trimethoxy silane styrene, vinyl trimethoxy silane, etc. Monomers containing silane, etc.

"(Meth)acrylate" means one or both of "acrylate" and "methacrylate". "(Meth)acrylic" means one or both of "acrylic" and "methacrylic". "(Meth)acryloyl" means one or both of "acryloyl" and "methacryloyl".

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 performing suspension polymerization in the presence of a radical polymerization initiator, a method of using non-crosslinked seed particles and a radical polymerization initiator to swell a monomer to perform polymerization, and the like.

When the substrate particles are inorganic particles other than metal or organic-inorganic mixed particles, examples of the inorganic substance used to form the substrate particles include silicon dioxide, aluminum oxide, barium titanate, zirconium oxide, and carbon black. Wait. Preferably, the above-mentioned inorganic substance is not a metal. The particles formed of the above-mentioned silicon dioxide are not particularly limited, and examples thereof include hydrolyzing silicides having two or more hydrolyzable alkoxysilane groups to form crosslinked polymer particles, and then firing them as necessary And the particles obtained. Examples of the organic-inorganic hybrid particles include organic-inorganic hybrid particles formed of a cross-linked alkoxysilane 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 the electrodes, the base material particles are preferably organic-inorganic mixed 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 materials of the resin particles.

As the material of the above-mentioned inorganic shell, there may be mentioned the inorganic substances exemplified as the material of the above-mentioned substrate particles. The material of the inorganic shell is preferably silicon dioxide. The inorganic shell is preferably formed by making a metal alkoxide into a shell on the surface of the core by a sol-gel method, and then baking the shell. The metal alkoxide is preferably a silane alkoxide. The inorganic shell is preferably formed of silane alkoxide.

When the substrate particles are metal particles, the metal used as the material of the metal particles may include silver, copper, nickel, silicon, gold, and titanium.

The particle diameter of the 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, still more preferably 50 μm or less . If the particle diameter of the substrate particles is above the lower limit and below the upper limit, the interval between the electrodes becomes smaller, and even if the thickness of the conductive layer is increased, smaller conductive particles can be obtained. Furthermore, when the conductive portion is formed on the surface of the base particle, it becomes difficult to aggregate, and it becomes difficult to form aggregated conductive particles.

The particle diameter of the above substrate particles is particularly preferably 2 μm or more and 50 μm or less. If the particle diameter of the substrate particles is within a range of 2 μm or more and 50 μm or less, it becomes difficult to aggregate when forming a conductive portion on the surface of the substrate particles, and it becomes difficult to form aggregated conductive particles.

The particle diameter of the above-mentioned substrate particles indicates the diameter when the substrate particles are truly spherical, and represents the maximum diameter when the substrate particles are not truly spherical.

The particle diameter of the above-mentioned substrate particles represents the number average particle diameter. The particle diameter of the above-mentioned 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 any 50 base material particles with an electron microscope or an optical microscope, and calculating an average value. In the case of measuring the particle diameter of the base particles among the conductive particles, for example, the measurement can be performed as follows.

It was added to "Technovit 4000" manufactured by Kulzer Corporation so that the content of the conductive particles became 30% by weight, and dispersed to produce an embedded resin for conductive particle inspection. Using an ion mill ("IM4000" manufactured by Hitachi High-Technologies Co., Ltd.), the cross section of the conductive particles was cut out so as to be dispersed near the center of the conductive particles embedded in the resin for inspection. Then, using a field emission scanning electron microscope (FE-SEM), the image magnification was set to 25,000 times, 50 conductive particles were randomly selected, and the substrate particles of each conductive particle were observed. The particle diameter of the substrate particles in each conductive particle is measured, and the arithmetic average of these is used as the particle diameter of the substrate particles.

Conductive Department: 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 metal may be a soft magnetic body. Only one kind of the above metals may be used, or two or more kinds may be used in combination. From the viewpoint of further reducing the connection resistance between the 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 made of the same material as the material constituting the conductive part, and the powder sample is measured using a "powder resistivity measuring system" manufactured by Mitsubishi Chemical Corporation When the volume resistance value is less than 0.005 Ω·cm.

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

Furthermore, there are many cases where hydroxyl groups are present on the surface of the conductive portion 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 on the surface of such a conductive part having a hydroxyl group (surface of conductive particles) through chemical bonding.

The conductive part may be formed by one layer. The conductive part may 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 a plurality of layers, the metal constituting the outermost layer is preferably gold, nickel, palladium, copper, or an alloy containing tin and silver, more preferably gold. In the case where the metal constituting the outermost layer is the preferred metal, the connection resistance between the electrodes becomes further lower. In addition, when the metal constituting the outermost layer is gold, the corrosion resistance is further increased.

The method of forming the conductive portion on the surface of the base particles is not particularly limited. Examples of the method for forming the conductive portion include: electroless plating method, electroplating method, physical collision method, mechanochemical reaction method, physical vapor deposition or physical adsorption method, and metal powder or metal The method of applying powder and adhesive paste on the surface of substrate particles. The above-mentioned method of forming the conductive portion is preferably a method of electroless plating, electroplating or physical collision. Examples of the above-mentioned physical vapor deposition method include vacuum vapor deposition, ion plating, and ion sputtering. In addition, as the above-mentioned physical collision method, for example, Thetacomposer (manufactured by Deshou Works Co., Ltd.) or the like 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 further preferably 0.3 μm or less. If the thickness of the conductive portion is not less than the lower limit and not more than the upper limit, sufficient conductivity can be obtained, and the conductive particles do not become too hard, and the conductive particles are sufficiently deformed during connection between the electrodes.

In the case where the conductive portion is formed of a plurality of layers, the thickness of the outermost conductive portion 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 above the lower limit and below the upper limit, the conductive portion of the outermost layer becomes uniform, the corrosion resistance becomes sufficiently high, and the connection resistance between the electrodes can be sufficiently reduced.

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

Core substance: The conductive particles preferably have a plurality of protrusions on the outer surface of the conductive portion. An oxide film is often formed on the surface of electrodes connected by conductive particles. In the case of using conductive particles having protrusions on the surface of the conductive portion, the conductive particles are arranged between the electrodes and crimped, so that the oxide film can be effectively eliminated by the protrusions. Therefore, the electrode and the conductive portion are more reliably contacted, and the connection resistance between the electrodes is further reduced. Furthermore, during the connection between the electrodes, the insulating particles between the conductive particles and the electrode can be effectively eliminated by the protrusions of the conductive particles. Therefore, the reliability of conduction between the electrodes is further increased.

As a method of forming the above-mentioned protrusions, a method of forming a conductive portion by electroless plating after attaching a core substance to the surface of the base particle; and forming a conductive portion by electroless plating on the surface of the base particle After that, the core material is adhered, and the method of forming the conductive portion by electroless plating is performed. As another method of forming the above-mentioned protrusions, after forming the first conductive portion on the surface of the base particle, a core substance is placed on the first conductive portion, and then the second conductive portion is formed; A method of adding a core substance in the middle of forming conductive parts (first conductive part, second conductive part, etc.) on the surface of the particles. In addition, in order to form protrusions, it is also possible to use: without using the above-mentioned core material, after forming the conductive portion by electroless plating on the substrate particles, the plating is deposited on the surface of the conductive portion into a protrusion shape, and Method for forming conductive part by electrolytic plating, etc.

As a method of attaching the core substance to the surface of the base particle, for example, a method of adding the core substance to the dispersion liquid of the base particle and accumulating the core substance due to the van der Waals force and attaching the core substance to the surface of the base particle ; And the method of adding the core substance to the container into which the substrate particles are placed, and attaching the core substance 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 attached core substance, the method of attaching the core substance to the surface of the substrate particle is preferably a method of accumulating and attaching the core substance to the surface of the substrate particle in the dispersion liquid.

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

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

The shape of the core material is not particularly limited. The shape of the core material is preferably massive. Examples of the core substance include agglomerates in the form of particles, agglomerates formed by agglomeration of a plurality of fine particles, and amorphous blocks.

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, and more preferably 0.2 μm or less. If the average diameter of the core material is above the lower limit and below the upper limit, the connection resistance between the electrodes can be effectively reduced.

The particle diameter of the core material is preferably an average particle diameter, more preferably a number average particle diameter. The particle diameter of the core material is determined by, for example, observing 50 arbitrary core materials by an electron microscope or an optical microscope, calculating the average particle diameter of each core material, or performing laser diffraction particle size distribution measurement. In observation by an electron microscope or an optical microscope, the particle diameter of each core substance is obtained as the particle diameter in terms of a circle-equivalent diameter. In observation by an electron microscope or an optical microscope, the average particle diameter in terms of a circle-equivalent diameter and the average particle diameter in terms of a spherical-equivalent diameter of any 50 core materials are approximately equal. In the laser diffraction type particle size distribution measurement, the particle diameter of each core substance is obtained as the particle diameter in terms of the equivalent diameter of the sphere. The particle diameter 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 portion. In this case, if the above conductive particles are used for the connection between the electrodes, it is possible to prevent short circuits between adjacent electrodes. Specifically, when a plurality of conductive particles are in contact, there are insulating particles between the plurality of electrodes, so that it is possible to prevent short circuits between the adjacent electrodes in the lateral direction instead of between the upper and lower electrodes. In addition, during the connection between the electrodes, by using two electrodes to pressurize the conductive particles, the insulating particles between the conductive portion of the conductive particles and the electrode can be easily excluded. Furthermore, when there are a plurality of protruding conductive particles on the outer surface of the conductive portion, the insulating particles between the conductive portion of the conductive particles and the electrode can be more easily excluded.

Examples of the material of the insulating particles include the material of the resin particles and the inorganic materials listed as the material of the substrate particles. The material of the insulating particles is preferably the material of the resin particles. The insulating particles are preferably the resin particles or the organic-inorganic mixed particles, and may be resin particles or organic-inorganic mixed 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, heat Curable resin and water-soluble resin. Only one kind of material for the insulating particles may be used, or two or more kinds may be used in combination.

Examples of the polyolefin compound include polyethylene, ethylene-vinyl acetate copolymer, and ethylene-acrylate copolymer. Examples of the (meth)acrylate polymer include polymethyl (meth)acrylate, polydodecyl (meth)acrylate, and polystearyl (meth)acrylate. 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 equivalent hydride. Examples of the thermoplastic resin include ethylene-based polymers and ethylene-based copolymers. Examples of the thermosetting resin include epoxy resins, phenol resins, and melamine resins. Examples of the cross-linked product of the thermoplastic resin include polyethylene glycol methacrylate, alkoxylated trimethylolpropane methacrylate, and alkoxylated pentaerythritol methacrylate. Examples of the water-soluble resin include polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinylpyrrolidone, polyethylene oxide, and methyl cellulose. In addition, in order to adjust the degree of polymerization, a chain transfer agent may be used. Examples of the chain transfer agent include mercaptans and carbon tetrachloride.

As a method of disposing the insulating particles on the surface of the conductive portion, a chemical method, a physical or mechanical method, etc. may be mentioned. Examples of the chemical method include an interfacial polymerization method, a suspension polymerization method in the presence of particles, and an emulsion polymerization method. Examples of the physical or mechanical methods include spray drying, mixing, electrostatic adhesion method, spray method, dipping and vacuum evaporation methods. In the case of electrically connecting between electrodes, from the viewpoint of further effectively improving insulation reliability and conduction reliability, the method of disposing the insulating particles on the surface of the conductive portion is preferably a physical method.

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

The particle size of the above-mentioned insulating particles can be appropriately selected according to the particle size of the conductive particles and the use of the conductive particles. The particle diameter of the insulating particles is preferably 10 nm or more, more preferably 100 nm or more, and further preferably 300 nm or more, particularly preferably 500 nm or more, preferably 4000 nm or less, more preferably 2000 nm or less, Furthermore, it is preferably 1500 nm or less, and 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 of the plurality of conductive particles are not likely to contact each other. If the particle size of the insulating particles is equal to or less than the above upper limit, in order to exclude the insulating particles between the electrodes and the conductive particles during the connection between the electrodes, there is no need to increase the pressure excessively, nor to heat to high temperature.

The particle diameter of the insulating particles is preferably an average particle diameter, 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 any 50 insulating particles with an electron microscope or an optical microscope, and calculating an average value. In the case of measuring the particle size of the insulating particles among the conductive particles, for example, the measurement can be performed as follows.

The conductive particles were added to "Technovit 4000" manufactured by Kulzer Corporation so that the content became 30% by weight, and dispersed to prepare an embedded resin for conductive particle inspection. Using an ion mill ("IM4000" manufactured by Hitachi High-Technologies Corporation), the cross-section of the conductive particles was cut out so as to pass near the center of the conductive particles dispersed in the inspection embedded resin. Then, using a field emission scanning electron microscope (FE-SEM), 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 is measured, and the arithmetic average of these is used 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 (the particle diameter of the conductive particles/the particle diameter of the insulating particles) is preferably 4 or more, more preferably 8 or more, and preferably 200 or less , More preferably 100 or less. If the above ratio (particle size of conductive particles/particle size of insulating particles) is above the lower limit and below the upper limit, when the electrodes are electrically connected, the insulation reliability and conduction can be further effectively improved reliability.

Soft magnetic body: The conductive particles preferably include a soft magnetic body portion arranged on the outer surface of the conductive portion. If the conductive particles include the soft magnetic body portion, the residual magnetization of the conductive particles can be further effectively reduced without impairing the conductivity of the conductive portion. As a result, the connection resistance between the electrodes can be further effectively reduced, and magnetic aggregation can be further effectively suppressed. In addition, 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 if the external magnetic field is removed, the magnetic force is quickly lost. The soft magnetic body 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 and the above ratio (residual magnetization/saturation magnetization) can be measured in the following order. A powder sample is made of the same material as the above-mentioned soft magnetic body. This powder sample was measured using the vibration sample type magnetometer ("PV-300-5" manufactured by Toei Scientific Industries Co., Ltd.) in the same order as the measurement of the 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 and the above ratio (residual magnetization/saturation magnetization) are obtained.

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

From the viewpoint of further effectively maintaining the connection resistance between the electrodes low and further effectively suppressing magnetic aggregation, it is preferable that the conductive particles include plural soft magnetic body portions. More specifically, the soft magnetic part contains soft magnetic particles, and preferably contains a plurality of the soft magnetic particles. As another specific aspect, the conductive particles are not covered by one soft magnetic body part over the entire outer surface of the conductive part, and it is preferable that a plurality of soft magnetic body parts exist in a spot-like manner with the conductive part exposed kind. In the conductive particles, it is preferable that a plurality of the soft magnetic body parts are separately arranged on the outer surface of the conductive part. The number of separated soft magnetic body parts is preferably 2 or more, more preferably 3 or more, still more preferably 5 or more, and particularly preferably 10 or more. The number of separated soft magnetic bodies can be appropriately set according to the surface area of the conductive particles.

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

When the soft magnetic body part is a particle, the particle size of the soft magnetic body part can be appropriately selected according to the particle size of the conductive particles and the use of the conductive particles. The particle diameter of the soft magnetic body portion 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 body portion is greater than or equal to the above 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 body portion is preferably an average particle diameter, preferably a number average particle diameter. The particle diameter of the soft magnetic body portion is obtained using a particle size distribution measuring device or the like. The particle diameter of the soft magnetic body portion is preferably determined by observing any 50 soft magnetic body portions with an electron microscope or an optical microscope, and calculating an average value. In the case of measuring the particle diameter of the soft magnetic body part in the conductive particles, for example, the measurement can be performed as follows.

The conductive particles were added to "Technovit 4000" manufactured by Kulzer Corporation so that the content became 30% by weight, and dispersed to prepare an embedded resin for conductive particle inspection. Using an ion mill ("IM4000" manufactured by Hitachi High-Technologies Corporation), the cross-section of the conductive particles was cut out so as to pass near the center of the conductive particles dispersed in the inspection embedded resin. Then, using a field emission scanning electron microscope (FE-SEM), the image magnification was set to 50,000 times, 50 conductive particles were randomly selected, and the soft magnetic body portion of each conductive particle was observed. The particle diameter of the soft magnetic body portion in each conductive particle is measured, and the arithmetic average of these is used as the particle diameter of the soft magnetic body portion.

When the soft magnetic body portion is a layer, the thickness of the soft magnetic body portion can be appropriately selected according to the particle diameter of the conductive particles and the use of the conductive particles. The thickness of the soft magnetic body portion 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 any 50 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 body part in the conductive particles, for example, the measurement can be performed as follows.

The conductive particles were added to the "Technovit 4000" manufactured by Kulzer Corporation so that the content became 30% by weight, and dispersed to produce an embedded resin for conductive particle inspection. Using an ion mill ("IM4000" manufactured by Hitachi High-Technologies Corporation), the cross-section of the conductive particles was cut out so as to pass near the center of the conductive particles dispersed in the inspection embedded resin. Then, using a field emission scanning electron microscope (FE-SEM), 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 portion in each conductive particle was measured, and the arithmetic average of these was used as the thickness of the soft magnetic body portion.

From the viewpoint of further effectively suppressing magnetic aggregation, it is preferable that the conductive portion is separated from the soft magnetic body portion. The distance between the conductive portion and the soft magnetic body portion is preferably 10 nm or more, more preferably 30 nm or more, and still more preferably 50 nm or more, preferably 800 nm or less, and more preferably 500 nm or less. If the above-mentioned distance from each other is more than the above 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 conductive portion and the soft magnetic body portion, 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 portion of each conductive particle and the soft magnetic body portion is measured, and the arithmetic average of these is used as the distance between the conductive portion and the soft magnetic body portion. In addition, when the conductive particles are provided with an insulating portion disposed between the conductive portion and the soft magnetic body portion, the thickness of the insulating portion measured according to the following method for measuring the thickness of the insulating portion may be used as the conductive The distance between the part and the soft magnetic body part.

The ratio of the area of the surface of the conductive portion covered by the soft magnetic body portion to the entire surface area of the conductive portion (coverage rate of the soft magnetic body portion) is preferably 5% or more, more preferably 10% or more, and more It is preferably 20% or more, more preferably 30% or more, still more preferably 40% or more, particularly preferably 45% or more, and most preferably 50% or more. The coverage rate of the soft magnetic body portion may be 80% or less. If the coverage 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 low, 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 rate of the above-mentioned soft magnetic body portion is obtained as follows.

Observe the conductive particles from one direction by a scanning electron microscope (SEM), and the total area of the soft magnetic body parts within the circle of the outer peripheral part of the surface of the conductive part accounts for the outer periphery of the surface of the conductive part in the observation image Calculated by the ratio of the entire area within a partial circle. The coverage of the soft magnetic body portion is preferably calculated as an average coverage obtained by observing 20 conductive particles and averaging the measurement results of the conductive particles.

Insulation: The conductive particles preferably include an insulating portion disposed between the conductive portion and the soft magnetic body portion. In the conductive particles, the soft magnetic body portion is preferably arranged on the outer surface of the conductive portion via the insulating portion. The soft magnetic body portion is preferably not in contact with the conductive portion. The insulating portion is preferably arranged between the conductive portion and the soft magnetic body portion. If the conductive particles satisfy the above-mentioned preferred aspect, the connection resistance between the electrodes can be further effectively reduced, and the magnetic aggregation can be further effectively suppressed.

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

The insulating portion is not particularly limited as long as it is an insulating material. Examples of the insulating portion include insulating resin. Examples of the insulating portion include materials of the insulating particles.

The method of disposing the soft magnetic body portion and the insulating portion on the outer surface of the conductive portion is not particularly limited. The method of arranging the soft magnetic body portion and the insulating portion on the outer surface of the conductive portion may be a method of arranging the insulating particles on the surface of the conductive portion. Specifically, as a method of arranging the soft magnetic body portion and the insulating portion on the outer surface of the conductive portion, the following methods may be mentioned. A method of arranging the insulating portion-coated soft magnetic body portion on the outer surface of the conductive portion after obtaining the insulating portion-coated soft magnetic body portion by covering the surface of the soft magnetic body portion with the insulating portion (in this case, The soft magnetic body part covered with the insulating part may be, for example, "FG beads" (registered trademark) manufactured by Tamagawa Seiki Co., Ltd. in 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 covers the conductive particles by covering the surface of the conductive portion with the insulating portion. After the particles are formed using the insulating portion, the soft magnetic body portion is arranged on the surface of the particle to obtain the particles with the soft magnetic body portion, and then the particles with the soft magnetic body portion are arranged outside the surface of the conductive portion Surface method.

The thickness of the insulating portion is preferably 10 nm or more, more preferably 30 nm or more, and 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 portion is a particle, the thickness of the insulating portion corresponds to the diameter of the particle.

The thickness of the insulating portion is preferably determined by observing any 50 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 conductive particles, for example, the measurement can be performed as follows.

The conductive particles were added to the "Technovit 4000" manufactured by Kulzer Corporation so that the content became 30% by weight, and dispersed to produce an embedded resin for conductive particle inspection. Using an ion mill ("IM4000" manufactured by Hitachi High-Technologies Corporation), the cross-section of the conductive particles was cut out so as to pass near the center of the conductive particles dispersed in the inspection embedded resin. Then, using a field emission scanning electron microscope (FE-SEM), 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 portion in each conductive particle is measured, and the arithmetic average of these is used as the thickness of the insulating portion.

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 surface of the soft magnetic body portion is covered with the insulating portion to obtain the insulating portion covering the soft magnetic body portion, the 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 particle. The soft magnetic particles covered with the insulating layer are obtained by coating the surface of the soft magnetic particles with the insulating layer. That is, it is preferable that the soft magnetic particles covered with the insulating layer are arranged on the outer surface of the conductive portion. In this case, the average particle diameter of the soft magnetic particles coated with the insulating layer 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 Below nm. If the average particle size of the soft magnetic particles coated with the insulating layer is at least the above lower limit, when the conductive particles are dispersed in the binder resin, the conductive layers of the plurality of conductive particles are not likely to contact each other, and the obtained connection structure The insulation reliability is improved. If the average particle diameter of the soft magnetic particles coated with the insulating layer is equal to or less than the above upper limit, it is difficult to separate from the surface of the conductive particles, and magnetic aggregation can be effectively suppressed.

In addition, the average particle diameter of the soft magnetic particles covered with the insulating layer can be measured in the following order, for example. The conductive particles were added to the "Technovit 4000" manufactured by Kulzer Corporation so that the content became 30% by weight, and dispersed to produce an embedded resin for conductive particle inspection. Using an ion mill ("IM4000" manufactured by Hitachi High-Technologies Corporation), the cross-section of the conductive particles was cut out so as to pass near the center of the conductive particles dispersed in the inspection embedded resin. Then, using a field emission scanning electron microscope (FE-SEM), the image magnification is set to 50,000 times, 50 conductive particles are randomly selected, and each conductive particle is arranged on the insulating layer on the outer surface of the conductive layer The particle size of the coated soft magnetic particles was observed. The particle size of the soft magnetic particles coated with the insulating layer in each conductive particle is measured, and the arithmetic average of these is used as the average particle size of the soft magnetic particles coated with the insulating layer.

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

The binder resin is not particularly limited. As the above-mentioned binder resin, a known insulating resin is used. The binder resin preferably contains a thermoplastic component (thermoplastic compound) or a curable component, and more preferably contains a curable component. Examples of the above-mentioned curable components 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, and elastomers. Only one kind of the above binder resin may be used, or two or more kinds may be used in combination.

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

The conductive material may contain, in addition to the conductive particles and the binder resin, for example: fillers, extenders, softeners, plasticizers, polymerization catalysts, curing catalysts, colorants, antioxidants, heat stabilizers , Light stabilizers, ultraviolet absorbers, lubricants, antistatic agents and flame retardants and other additives.

The method for dispersing the conductive particles in the binder resin may use a previously known dispersion method, and is not particularly limited. Examples of the method for dispersing the conductive particles in the binder resin include the following methods. After adding the above-mentioned conductive particles to the above-mentioned binder resin, a method of kneading and dispersing by a planetary mixer or the like. A method of uniformly dispersing the conductive particles in water or an organic solvent using a homogenizer or the like, then adding to the binder resin, and mixing by a planetary mixer or the like to disperse them. After diluting the binder resin with water, an organic solvent, or the like, the conductive particles are added, and a method of mixing by a planetary mixer or the like to disperse them is performed.

The viscosity (η25) of the 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 lower limit and below the 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 type and amount of formulated ingredients.

The 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 Industry Corporation).

The conductive material of the present invention can be used as a conductive paste, a conductive film, and the like. When the conductive material of the present invention is a conductive film, a film containing no conductive particles may be laminated on the conductive film containing conductive particles. The conductive paste is preferably an anisotropic conductive paste. The conductive film is preferably an anisotropic conductive film.

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

In 100% by weight of the conductive material, the content of the conductive particles is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, preferably 80% by weight or less, more preferably 60% by weight or less, and further preferably 40% by weight or less, particularly preferably 20% by weight or less, and most preferably 10% by weight or less. If the content of the conductive particles is more than the lower limit and less than the upper limit, the conduction reliability and insulation reliability between the electrodes can be further improved. If the content of the conductive particles is more than the lower limit and less than the 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 the surface, a second connection object member having a second electrode on the surface, and a connection 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 portion is the conductive particles or a conductive material (the conductive material) containing the conductive particles and the binder resin. In the connection structure of the present invention, the first electrode and the second electrode are electrically connected by the conductive portion in the conductive particles.

The connection structure can be obtained by the steps of arranging the conductive particles or the conductive material between the first connection object member and the second connection object member, and the step of performing conductive connection by thermocompression bonding . When the conductive particles have 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 connection 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 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 the convenience of illustration, the conductive particles 1 are shown in outline. The conductive particles 11, 21, 31, 41 or 51 can be used instead of the 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 by the conductive portion in the conductive particles 1.

The manufacturing method of the connection structure is not particularly limited. As an example of a method of manufacturing a connection structure, the following method may be mentioned: the conductive material is disposed between the first connection object member and the second connection object member, and after obtaining the laminate, the laminate is heated and pressurized. 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 of the aforementioned 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 lower limit and below the upper limit, the conduction reliability between the electrodes can be further improved. In addition, when the conductive particles have the insulating particles, the insulating particles can be easily detached from the surface of the conductive particles during conductive connection.

When the conductive particles have the insulating particles, when the laminated body is heated and pressurized, the insulating properties existing between the conductive particles and the first electrode and the second electrode can be excluded particle. For example, during the heating and pressurization, the insulating particles existing between the conductive particles and the first electrode and the second electrode are easily detached from the surface of the conductive particles. In addition, there are cases where part of the insulating particles is detached from the surface of the conductive particles during the heating and pressing, and the surface of the conductive portion is exposed. Since the exposed portion of the surface of the conductive portion is in contact with the first electrode and the second electrode, the first electrode and the second electrode can be electrically connected via 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 semiconductor chips, semiconductor packages, LED (Light Emitting Diode) chips, LED packages, capacitors, and diodes. , And electronic components such as resin film, printed circuit board, flexible printed circuit board, flexible flat cable, rigid flexible circuit board, glass epoxy substrate and glass substrate and other circuit boards. The first connection object member and the second connection object member are preferably electronic parts.

Examples of the electrodes provided on the connection target member include gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, copper electrodes, molybdenum electrodes, silver electrodes, SUS (Steel Use Stainless, Japan Stainless Steel) electrodes, and tungsten electrodes. electrode. When the connection object 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. Furthermore, when the above electrode is an aluminum electrode, it may be an electrode formed only of aluminum, or an electrode having an aluminum layer on the surface area of the metal oxide layer. Examples of the material of the metal oxide layer include indium oxide doped with trivalent metal elements and zinc oxide doped with trivalent metal elements. Examples of the trivalent metal element include Sn, Al, and Ga.

Hereinafter, examples and comparative examples will be listed to specifically explain the present invention. The present invention is not limited to the following embodiments.

(Example 1) (1) Fabrication of conductive particles Prepare substrate particles of 3 μm particle diameter made of copolymer resin of tetramethylol methane tetraacrylate and divinylbenzene. After dispersing 10 parts by weight of substrate particles in 100 parts by weight of an alkaline solution containing 5% by weight of a palladium catalyst solution by using an ultrasonic disperser, the solution was filtered to remove 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 sufficiently washed with water, 500 parts by weight of distilled water is added to disperse them to obtain a dispersion liquid. 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 a core substance adhered.

In addition, a nickel plating solution (pH 8.5) containing 0.35 mol/L nickel sulfate, 1.38 mol/L dimethylamineborane and 0.5 mol/L sodium citrate was prepared.

While stirring the obtained suspension at 60°C, the above nickel plating solution was slowly added dropwise to the suspension to perform electroless nickel plating. Thereafter, the particles were taken out by filtering the suspension, washed with water, and dried to obtain conductive particle bodies having a nickel-boron conductive layer (thickness 0.15 μm) formed on the surface of the base particles.

(2) Fabrication of soft magnetic particles covered with insulating layer The surface of the soft magnetic particles (soft magnetic body portion) is coated with an insulating layer (insulating portion) as described below.

After placing a composition containing the following polymerizable compound into a 500 mL separable flask equipped with a four-port separable lid, a stirring blade, a three-way stopcock, a condenser and a temperature probe, use an ultrasonic irradiator to make it Fully emulsified. Thereafter, the mixture was stirred at 200 rpm, and polymerization was carried out under nitrogen atmosphere at 50°C for 5 hours. 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) and 0.1 parts by weight of 2,2' -Azobis{2-[N-(2-carboxyethyl)amidino]propane}. Furthermore, the said composition contains 0.1 weight part of polyoxyethylene lauryl ether ("Emulgen 106" by Kao Corporation), 1.7 weight part of methyl methacrylate, and 0.1 weight part of ethylene glycol dimethacrylate. After the reaction is completed, it is cooled, the solid-liquid separation is performed twice by a centrifugal separator, and the excess polymerizable compound is removed by washing to obtain an insulating layer covering the entire surface of the soft magnetic particles covered by the coating portion. (Particle size 50 nm), 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 coated with soft magnetic particles with an insulating layer) The obtained particles (A) were dispersed in distilled water under ultrasonic irradiation to obtain a 10% by weight aqueous dispersion of particles (A). Disperse 10 parts by weight of the obtained substrate particles (conductive particle body) having conductive parts on the surface in 100 parts by weight of distilled water, add 1 part by weight of 10% by weight aqueous dispersion of particles (A) at room temperature Stir for 8 hours. After filtering through a 5 μm mesh filter, it was further washed with methanol and dried to obtain conductive particles with particles (A) attached to the conductive particle body.

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

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

The obtained anisotropic conductive paste was applied on the transparent glass substrate with a thickness of 30 μm to form an anisotropic conductive paste layer. Next, the semiconductor wafer is stacked on the anisotropic conductive paste layer so that the electrodes face each other. After that, while adjusting the temperature of the head so that the temperature of the anisotropic conductive paste layer becomes 100°C, the pressure heating head is placed on the upper surface of the semiconductor wafer, and a pressure of 60 MPa is applied to make the anisotropic conductive paste The layer was hardened at 100°C to obtain a connection structure.

(Examples 2-7, 10-12 and Comparative Examples 3, 4) As shown in Table 1 below, set the type of soft magnetic body part, the coverage 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 particle is coated with the insulating layer, and Except for the average particle diameter of the particles (A), the same procedure as in Example 1 was carried out to obtain conductive particles, conductive materials, and connection structures.

In Example 10, nickel-iron alloy particles having an average particle diameter of 30 nm formed by a dry milling device of a hammer mill or a ball mill were used instead of iron oxide nanoparticles. Further, in Example 12, iron-cobalt alloy particles having an average particle diameter of 30 nm formed by iron-cobalt alloy powder (manufactured by Datong Special Steel Co., Ltd.) by a dry milling device of a hammer mill or a ball mill were used. In addition, in Comparative Example 4, a nickel paste having an average particle diameter of 30 nm was used. In addition, the coverage rate of the soft magnetic body parts of Examples 2 to 7, 10 to 12 and Comparative Examples 3 and 4 was changed by 10 of the particle (A) when the conductive particles coated with the soft magnetic particles with an insulating layer were produced Adjust the amount of the weight% aqueous dispersion.

(Example 8) (1) Fabrication of conductive particles The conductive particle body was produced in the same manner as in Example 1.

(2) Fabrication of conductive particles covered with insulation The surface of the conductive particle body is covered with an insulating layer (insulating portion) as described below.

After placing a composition containing the following polymerizable compound into a 500 mL separable flask equipped with a four-port separable lid, a stirring blade, a three-way stopcock, a condenser and a temperature probe, use an ultrasonic irradiator to make it Fully emulsified. Thereafter, the mixture was stirred at 200 rpm, and polymerization was carried out under nitrogen atmosphere at 50°C for 5 hours. 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)amidino ]Propane}. Furthermore, the said composition contains 0.1 weight part of polyoxyethylene lauryl ether ("Emulgen 106" by Kao Corporation), 0.1 weight part of methyl methacrylate, and 0.1 weight part of ethylene glycol dimethacrylate. After the reaction is completed, it is cooled, the solid-liquid separation is performed twice by a centrifugal separator, and the excess polymerizable compound is removed by washing to obtain an insulating portion coated with conductive particles covered by the coating portion on the entire surface of the conductive particle body ( The thickness of the insulating layer is 50 nm), and the above-mentioned covered portion is formed of a polymerizable compound.

(3) Preparation of conductive particles (conductive particles with insulating layer and soft magnetic particles) The surface of the insulating layer in the conductive particles is covered with the soft magnetic particles (soft magnetic body portion) covering the insulating portion as described below.

Under ultrasonic irradiation, iron oxide nanoparticles with a diameter of 30 nm (composition: maghemite or magnetite, manufactured by Sigma-Aldrich) were dispersed in distilled water to obtain a 10% by weight aqueous dispersion. 10 parts by weight of the obtained insulating-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, it is further washed with methanol and dried to obtain conductive particles (with an insulating layer and soft magnetism) where the iron oxide nanoparticles adhere to the coated conductive particles on the insulating portion Conductive particles of bulk particles).

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

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

(Example 9) (1) Fabrication of conductive particles The conductive particle body was produced in the same manner as in Example 1.

(2) Fabrication of insulating particles coated with soft magnetic particles The insulating particles are formed as follows.

Into a 500 mL separable flask equipped with a four-port separable lid, a stirring blade, a three-way stopcock, a condenser, and a temperature probe, put a composition containing the following polymerizable compound, and stir at 200 rpm. The polymerization was carried out at 50°C for 5 hours under a nitrogen atmosphere. The above composition contains 200 parts by weight of distilled water, 0.2 parts by weight of acid phosphaoxypolyoxyethylene methacrylate, 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 completion of the reaction, it was cooled, and the solid-liquid separation was performed twice by a centrifugal separator, and excess polymerizable compounds were removed by washing to obtain insulating particles (particle size: 300 nm).

The surface of the obtained insulating particles is coated with soft magnetic particles (soft magnetic body parts) as described below.

Under ultrasonic irradiation, iron oxide nanoparticles with a diameter of 30 nm (composition: maghemite or magnetite, manufactured by Sigma-Aldrich) were dispersed in distilled water 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 stirred at room temperature for 8 hours. After filtering through a 5 μm mesh filter, it was further washed with methanol and dried to obtain soft magnetic particles coated with insulating particles with iron oxide nanoparticles attached to the insulating particles.

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

The obtained soft magnetic particle-coated insulating particles were dispersed in distilled water under ultrasonic irradiation to obtain a 10% by weight aqueous dispersion. 10 parts by weight of the conductive particle body was dispersed in 100 parts by weight of distilled water, 1 part by weight of a 10% by weight aqueous dispersion of soft magnetic particles coated insulating particles was added, and stirred at room temperature for 8 hours. After filtering with a 5 μm mesh filter, it is washed with methanol and then dried to obtain soft magnetic particles. The coated insulating particles are conductive particles attached to the conductive particle body (with soft magnetic particles) Conductive particles coated with insulating particles).

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

(5) Fabrication of connection structure Except having used the obtained conductive material, 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 conductive particles. Except this conductive particle, it carried out similarly to Example 1, and obtained the conductive material and the connection structure.

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

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

Under ultrasonic irradiation, iron oxide nanoparticles with a diameter of 30 nm (composition: maghemite or magnetite, manufactured by Sigma-Aldrich) were dispersed in distilled water to obtain a 10% by weight aqueous dispersion. 10 parts by weight of the conductive particles were dispersed in 100 parts by weight of distilled water, 1 part by weight of 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, it was further washed with methanol and dried to obtain soft magnetic particles coated with conductive iron particles on which the iron oxide nanoparticles adhered to the conductive particle body.

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

(4) Fabrication of connection structure Except having used the obtained conductive material, it carried out similarly to Example 1, and obtained the connection structure.

(Evaluation) (1) Residual magnetization and saturation magnetization of conductive particles Using the capsule enclosed with nickel powder as the calibration sample of the device, the calibration of the vibrating sample type magnetometer ("PV-300-5" manufactured by Dongrong Scientific Industry Corporation) is performed. Weigh the obtained conductive particles in a capsule and install them in the sample holder. The sample holder was set on the magnetometer body, and the measurement was performed 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, thereby obtaining a magnetization curve. Based on the obtained magnetization curve, the residual magnetization and saturation magnetization of the conductive particles are determined.

In addition, the ratio of residual magnetization to saturation magnetization (residual magnetization/saturation magnetization) was calculated from the measurement results.

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

The coverage rate of the soft magnetic body part was calculated as follows.

The conductive particles obtained by observing from one direction by a scanning electron microscope (SEM), based on the total area of the soft magnetic body parts in the circle of the peripheral part outside the surface of the conductive part, occupy the surface of the conductive part in the observation 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 insulation The thickness of the insulating part 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 dispersed to prepare an embedded resin for conductive particle inspection. Using an ion mill ("IM4000" manufactured by Hitachi High-Technologies Corporation), the cross-section of the conductive particles was cut out so as to pass near the center of the conductive particles dispersed in the inspection embedded resin. Then, using a field emission scanning electron microscope (FE-SEM), 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 portion in each conductive particle is measured, and the arithmetic average of these is used as the thickness of the insulating portion.

(4) Magnetic aggregation of conductive particles Observe the obtained conductive material to confirm whether magnetic aggregation of conductive particles occurs. The magnetic aggregation of the conductive particles was determined according to the following conditions.

[Judgment criteria for magnetic aggregation of conductive particles] ○○: No magnetic aggregation of conductive particles ○: Magnetic aggregation of conductive particles occurs slightly, but suppression effect is confirmed ×: Magnetic aggregation of conductive particles occurs

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

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

(6) Insulation reliability (between adjacent electrodes in the lateral direction) Among the 20 connection structures obtained in the evaluation of the conduction reliability in (5) above, the presence or absence of leakage between adjacent electrodes was evaluated by measuring the resistance value using a tester. Evaluate the insulation reliability according to the following criteria.

[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 connecting structures with resistance value of 10 ⁸ Ω or more is less than 10

The details and results are shown in Tables 1 and 2 below.

[Table 1]

[Table 2]

The conductive particles obtained in Examples 1 to 12 were compared with the conductive particles obtained in Comparative Examples 1 to 4, and the magnetic aggregation of the conductive particles was suppressed.

In addition, 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. It is considered that the reason is that in the conductive particles obtained in Example 8, the entire surface of the conductive particle body is covered with the insulating portion, so the exposure of the conductive layer is relatively small. In contrast, in Examples 1 to 7, 10 Among the conductive particles obtained in ~12, the soft magnetic particles are covered with the insulating layer, so the conductive layer is exposed a lot.

In addition, the conductive particles obtained in Examples 1 to 7 and 10 to 12 showed a lower connection resistance than the conductive particles obtained in Example 9. It is considered that the reason is that, in the conductive particles of Example 9, iron oxide nanoparticles having an average particle diameter of 30 nm were attached to insulating particles having an average particle diameter of 300 nm, and the soft magnetic particles covered the insulating particles. The average particle diameter is larger (average particle diameter exceeding 300 nm), compared to this, in the conductive particles of Examples 1 to 7, 10 to 12, the average particle diameter of the soft magnetic particles coated with the insulating layer is small (50 nm ~ 130 nm average particle size). Therefore, during the thermocompression bonding during the fabrication of the connection structure, in the conductive particles of Example 9, the insulating particles are not easily detached from the surface of the conductive particles. In contrast, in Examples 1 to 7, 10 to 12. Among the conductive particles, the soft magnetic particles covered by the insulating layer 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 31: Conductive particles 32: Insulation 41: Conductive particles 42: Insulation 51: conductive particles 52: Insulation 61: conductive part 62: Core substance 63: protrusion 81: connection structure 82: The first connection target component 82a: 1st electrode 83: Second connection target component 83a: 2nd electrode 84: connection

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

Claims (11)

A conductive particle comprising a base particle and a conductive portion arranged on the surface of the base particle, and a ratio of residual magnetization to saturation magnetization is 0.6 or less. The conductive particles according to claim 1, wherein the above-mentioned residual magnetization is 0.02 A/m or less. The conductive particle according to claim 1 or 2 includes a soft magnetic body part disposed on the outer surface of the conductive part. The conductive particle according to claim 3 includes an insulating portion disposed between the conductive portion and the soft magnetic body portion, and the soft magnetic body portion is disposed on the outer surface of the conductive portion via the insulating portion. The conductive particles according to claim 4, wherein the distance between the conductive portion and the soft magnetic body portion is 10 nm or more and 500 nm or less. The conductive particle according to claim 3 includes 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 particles according to claim 3, wherein the area 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 particles according to claim 7, wherein the area 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 according to claim 1 or 2 include a plurality of insulating particles arranged on the outer surface of the conductive portion. A conductive material containing conductive particles as described in claim 1 or 2 and a binder resin. A connection structure with: The first connection object member having the first electrode on the surface, A second connection object member having a second electrode on the surface, and A connection portion that connects the first connection object member and the second connection object member; and The material of the connection part is the conductive particles according to any one of claims 1 to 9, or a conductive material containing the conductive particles and the binder resin, The first electrode and the second electrode are electrically connected by the conductive portion in the conductive particles.

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