JP2021057188A - Conductive particle, conductive material, connection structure and method for producing connection structure - Google Patents

Abstract

To provide a conductive particle that can reduce connection resistance after conductive connection.SOLUTION: A conductive particle includes a base particle and a conductive part disposed on the surface of the base particle and has an amount of saturation magnetization of 10 emu/g or more.SELECTED DRAWING: Figure 1

Description

The present invention relates to conductive particles that can be used for electrical connection between electrodes and the like. The present invention also relates to a conductive material, a connecting structure, and a method for manufacturing the connecting structure using the conductive particles.

Anisotropic conductive materials such as anisotropic conductive pastes and anisotropic conductive films are widely known. In the anisotropic conductive material, conductive particles are dispersed in the binder resin. Further, as the conductive particles, conductive particles having a base material particles and a conductive portion arranged on the surface of the base material particles may be used.

The anisotropic conductive material is used to obtain various connection structures. Connections using the anisotropic conductive material include a connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)), a connection between a semiconductor chip and a flexible printed circuit board (COF (Chip on Film)), and a semiconductor chip. The connection between the glass substrate and the glass substrate (COG (Chip on Glass)), the connection between the flexible printed circuit board and the glass epoxy substrate (FOB (Film on Board)), and the like can be mentioned.

Further, as the conductive particles, magnetic conductive particles may be used. Patent Document 1 below discloses an anisotropic conductive sheet in which conductive particles are arranged at predetermined positions by locally applying a magnetic field to attract the conductive particles toward the magnetic field. .. Further, in Example 1 of Patent Document 1, nickel particles entirely formed of nickel are used as the conductive particles having magnetism.

Patent Document 2 discloses conductive particles including resin particles, a metal plating layer formed on the surface of the resin particles, and an insulating layer formed on the outer surface of the metal plating layer. The metal plating layer may be a magnetic metal plating layer containing at least one of Fe, Ni, and Co.

Japanese Unexamined Patent Publication No. 2006-093020 Japanese Unexamined Patent Publication No. 2013-045565

In Patent Document 1, when an anisotropic conductive sheet is obtained, a magnetic field is applied and the conductive particles are arranged at predetermined positions in the sheet. However, in such an anisotropic conductive sheet, it is necessary to accurately align the electrodes with respect to the positions of the conductive particles at the time of conductive connection.

Further, in the case of nickel particles entirely made of nickel as described in Patent Document 1, when a magnetic field is applied, the moving speed of the conductive particles may be slow due to the weight of the particles. In addition, the electrodes may be damaged in the connection structure conductively connected by nickel particles. For example, the electrodes may be damaged when the nickel particles move or when crimping between the electrodes via the nickel particles. As a result, the connection resistance after the conductive connection may increase.

Further, as described in Patent Document 2, when a magnetic metal plating layer is formed by using at least one of Fe, Ni, and Co and magnetized, the particles aggregate with each other and a magnetic field is applied. In some cases, it may not be possible to accurately align the electrodes. As a result, the conductive connection may not be sufficiently established.

An object of the present invention is to provide conductive particles capable of easily moving and aligning conductive particles when forming an electrode portion using magnetic force, and reducing connection resistance after conductive connection. That is. Another object of the present invention is to provide a conductive material, a connecting structure, and a method for manufacturing the connecting structure using the conductive particles.

According to a broad aspect of the present invention, there is provided a conductive particle having a base particle and a conductive portion arranged on the surface of the base particle and having a saturation magnetization amount of 10 emu / g or more. ..

In certain aspects of the conductive particles according to the present invention, the substrate particles are not metal particles.

In certain aspects of the conductive particles according to the present invention, the substrate particles are resin particles or organic-inorganic hybrid particles.

In certain aspects of the conductive particles according to the present invention, the conductive portion comprises nickel, cobalt or iron.

In a specific aspect of the conductive particles according to the present invention, the total content of nickel, cobalt and iron in 100% by weight of the conductive portion is 90% by weight or more.

In a specific aspect of the conductive particles according to the present invention, the conductive portion contains at least two kinds of nickel, cobalt and iron, and the content of nickel and the content of cobalt in 100% by weight of the conductive portion. And the content of one of the iron contents is 51% by weight or more.

In a specific aspect of the conductive particles according to the present invention, the compression modulus when the base particle is compressed by 10% at 25 ° C. is at 1000 N / mm ² or more 30000 N / mm ² or less.

In a specific aspect of the conductive particles according to the present invention, the particle size of the base particles is 1 μm or more and 10 μm or less.

In a specific aspect of the conductive particles according to the present invention, the specific gravity of the base particles is lower than the specific gravity of the conductive portion.

In certain aspects of the conductive particles according to the present invention, the conductive particles are used in a conductive connection to which a magnetic field or magnetic force is applied.

In certain aspects of the conductive particles according to the present invention, the conductive particles have protrusions on the outer surface of the conductive portion.

In certain aspects of the conductive particles according to the present invention, the conductive particles include an insulating material disposed 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-mentioned conductive particles and a binder resin.

According to a broad aspect of the present invention, a first connection target member having a first electrode on the surface, a second connection target member having a second electrode on the surface, the first connection target member, and the above. It is provided with a connecting portion connecting the second connection target member, and the material of the connecting portion is the above-mentioned conductive particles or a conductive material containing the conductive particles and a binder resin. Provided is a connection structure in which the first electrode and the second electrode are electrically connected by the conductive particles.

According to a broad aspect of the present invention, the above-mentioned conductive particles are arranged on the surface of the first connection target member having the first electrode on the surface, or the conductive particles and the conductive material containing the binder resin are contained. A second connection target member having a second electrode on the surface opposite to the first placement step of arranging the material and the conductive particles or the first connection target member side of the conductive material. The first electrode and the second electrode are formed by the conductive particles, comprising a second arrangement step of arranging the first electrode and a step of applying a magnetic field or a magnetic force before or after the second arrangement step. A method for manufacturing a connection structure is provided, which obtains a connection structure that is electrically connected.

The conductive particles according to the present invention include base particles and conductive portions arranged on the surface of the base particles. In the conductive particles according to the present invention, the saturation magnetization amount is 10 emu / g or more. Since the conductive particles according to the present invention have the above-mentioned structure, the connection resistance after the conductive connection can be lowered.

FIG. 1 is a cross-sectional view showing conductive particles according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing conductive particles according to a second embodiment of the present invention. FIG. 3 is a cross-sectional view showing conductive particles according to a third embodiment of the present invention. FIG. 4 is a cross-sectional view showing conductive particles according to a fourth embodiment of the present invention. FIG. 5 is a front sectional view schematically showing a connection structure using conductive particles according to the first embodiment of the present invention. FIG. 6 is a front sectional view for explaining a method of manufacturing the connection structure shown in FIG. FIG. 7 is a front sectional view for explaining another method for manufacturing the connection structure shown in FIG.

The details of the present invention will be described below.

(Conductive particles)
The conductive particles according to the present invention include base particles and conductive portions arranged on the surface of the base particles. In the conductive particles according to the present invention, the saturation magnetization amount is 10 emu / g or more.

Since the conductive particles according to the present invention have the above-mentioned structure, the connection resistance after the conductive connection can be lowered.

Since the saturated magnetization amount of the conductive particles according to the present invention is 10 emu / g or more, the conductive particles can be effectively moved by applying a magnetic field or a magnetic force. For example, by applying a magnetic field or magnetic force at the electrode portion, the conductive particles can be effectively moved on or between the electrodes. As a result, in the conductive particles according to the present invention, the number of conductive particles arranged between the upper and lower electrodes to be connected increases, and the connection resistance decreases. Further, it is difficult to electrically connect the electrodes adjacent to each other in the lateral direction, which should not be connected, and the problem of short circuit is less likely to occur.

Further, simply using conductive metal particles having a high saturation magnetization amount may increase the connection resistance. Since the conductive particles according to the present invention are provided with the base particles, the electrodes are less likely to be damaged when the conductive particles move. Further, since the conductive particles according to the present invention are provided with the above-mentioned base material particles, even if the conductive particles are compressed between the upper and lower electrodes, the electrodes are less likely to be damaged. As a result, the connection resistance can be lowered.

From the viewpoint of moving the conductive particles more effectively, the saturated magnetization amount of the conductive particles is preferably 15 emu / g or more, more preferably 20 emu / g or more. The higher the saturation magnetization amount, the better. From the viewpoint of easily producing the conductive particles, the saturated magnetization amount of the conductive particles may be 300 emu / g or less, or 100 emu / g or less.

The saturated magnetization amount can be controlled by the type and content of the metal used for the conductive portion, the thickness of the conductive portion, and the like.

The amount of saturation magnetization is measured as follows.

The amount of magnetization can be calculated by measuring the magnetic hysteresis curve of the conductive particles. As the apparatus, a vibration sample type magnetometer (“BHV-50” manufactured by RIKEN Electronics Co., Ltd.) or the like is used. Further, the sample can be prepared and the measurement can be carried out by sealing the dried conductive particles (15 mg) in the sample holder without compression.

Compression modulus when the base particle is compressed by 10% at 25 ° C. (10% K value), preferably 1000 N / mm ² or more, more preferably 3000N / mm ² or more, preferably 30000 N / mm ² Hereinafter, it is more preferably 20000 N / mm ² or less. When the 10% K value of the base material particles is not less than the above lower limit and not more than the above upper limit, damage to the electrodes can be further suppressed, and the connection resistance can be effectively lowered. Further, when the conductive portion is formed on the surface, aggregation can be suppressed more effectively, and the occurrence of plating cracks and plating peeling can be suppressed even more effectively.

The compressive elastic modulus (10% K value) of the base particles can be measured as follows.

A microcompression tester is used to compress a single substrate particle on a cylindrical (diameter 50 μm, diamond) smoothing indenter end face under conditions of 25 ° C., a compression rate of 0.3 mN / sec, and a maximum test load of 20 mN. To do. At this time, the load value (N) and the compressive displacement (mm) are measured. From the obtained measured values, the compressive elastic modulus (10% K value) of the base particles can be calculated by the following formula. As the microcompression tester, for example, "Fisherscope H-100" manufactured by Fisher Co., Ltd. is used. The compressive elastic modulus (10% K value) of the base particles is preferably calculated by arithmetically averaging the compressive elastic moduli (10% K value) of 50 arbitrarily selected particles.

10% K value (N / mm ² ) = (3/2 ^1/2 ) ・ F ・ S ^-3/2・ R- ^{1 / 2}
F: Load value (N) when the base particle is compressed and deformed by 10%
S: Compressive displacement (mm) when the substrate particles are compressed and deformed by 10%
R: Radius of substrate particles (mm)

The compressive elastic modulus universally and quantitatively represents the hardness of particles. By using the compressive elastic modulus, the hardness of the base particle can be expressed quantitatively and uniquely.

From the viewpoint of effectively moving the conductive particles by a magnetic field or a magnetic force and further lowering the connection resistance, it is preferable that the specific gravity of the base material particles is lower than the specific gravity of the conductive portion. It is more preferable that the specific gravity of the base material particles is 3 g / cm ^{3 or more lower than the specific gravity of the conductive portion.} It is more preferable that the specific gravity of the base particles is 5 g / cm ^{3 or more lower than the specific gravity of the conductive portion.} Generally, the specific gravity of the resin particles or the organic hybrid particles is lower than the specific gravity of the conductive portion formed of the metal.

The conductive particles are suitably used for a conductive connection to which a magnetic field or a magnetic force is applied. By applying a magnetic field or magnetic force at the time of conductive connection, the conductive particles can be effectively moved on or between electrodes.

The particle size of the conductive particles is preferably 0.1 μm or more, more preferably 1 μm or more, preferably 1000 μm or less, more preferably 100 μm or less, still more preferably 10 μm or less. When the particle diameter of the conductive particles is equal to or greater than the above lower limit and equal to or less than the above upper limit, the contact area between the conductive particles and the electrodes becomes sufficiently large when the electrodes are connected using the conductive particles. Moreover, it becomes difficult to form agglomerated conductive particles when forming the conductive portion. In addition, the distance between the electrodes connected via the conductive particles does not become too large, and the conductive portion does not easily peel off from the surface of the substrate particles.

The particle size of the conductive particles is preferably an average particle size, and preferably a number average particle size. For the particle size of the conductive particles, for example, 50 arbitrary conductive particles are observed with an electron microscope or an optical microscope, the average value of the particle size of each conductive particle is calculated, or a particle size distribution measuring device is used. It is required. In observation with an electron microscope or an optical microscope, the particle size of each conductive particle is determined as the particle size in a circle-equivalent diameter. In observation with an electron microscope or an optical microscope, the average particle diameter of any 50 conductive particles in a circle-equivalent diameter is substantially equal to the average particle diameter in a sphere-equivalent diameter. In the particle size distribution measuring device, the particle size of each conductive particle is obtained as the particle size in the equivalent diameter of a sphere. The average particle size of the conductive particles is preferably calculated using a particle size distribution measuring device. From the viewpoint of high measurement accuracy, the particle size distribution measuring device is preferably a laser diffraction type particle size distribution measuring device.

The coefficient of variation (CV value) of the particle size of the conductive particles is preferably 10% or less, more preferably 5% or less. When the coefficient of variation of the particle size of the conductive particles is not more than the above upper limit, the conduction reliability and the 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 particle size of conductive particles Dn: Mean value of particle size of conductive particles

The shape of the conductive particles is not particularly limited. The shape of the conductive particles may be spherical, non-spherical, flat or the like.

Hereinafter, the present invention will be specifically described with reference to the drawings. In addition, in FIG. 1 and the figure described later, different parts can be replaced with each other.

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

The conductive particle 1 shown in FIG. 1 has a base particle 2 and a conductive portion 3. The conductive portion 3 is arranged on the surface of the base particle 2. In the first embodiment, the conductive portion 3 is in contact with the surface of the base particle 2. The conductive particles 1 are coated particles in which the surface of the base particle 2 is coated with the conductive portion 3.

In the conductive particles 1, the conductive portion 3 is a single-layer conductive layer. In the conductive particles, the conductive portion may cover the entire surface of the base material particles, or the conductive portion may cover a part of the surface of the base material particles. In the conductive particles, the conductive portion may be a single-layer conductive layer or a multi-layer conductive layer composed of two or more layers.

The conductive particles 1 do not have a core substance, unlike the conductive particles 11 and 21 described later. The conductive particles 1 have no protrusions on the surface. The conductive particles 1 are spherical. The conductive portion 3 has no protrusion on the outer surface. As described above, the conductive particles according to the present invention do not have to have protrusions on the conductive surface, and may be spherical. Further, the conductive particles 1 do not have an insulating substance, unlike the conductive particles 11 and 21 described later. However, the conductive particles 1 may have an insulating substance 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 has a base particle 2, a conductive portion 12, a plurality of core substances 13, and a plurality of insulating substances 14. The conductive portion 12 is arranged on the surface of the base particle 2 so as to be in contact with the base particle 2.

In the conductive particles 11, the conductive portion 12 is a single-layer conductive layer. In the conductive particles, the conductive portion may cover the entire surface of the base material particles, or the conductive portion may cover a part of the surface of the base material particles. In the conductive particles, the conductive portion may be a single-layer conductive layer or a multi-layer conductive layer composed of two or more layers.

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

The conductive particles 11 have an insulating substance 14 arranged on the outer surface of the conductive portion 12. At least a part of the outer surface of the conductive portion 12 is covered with the insulating substance 14. The insulating substance 14 is formed of an insulating material and is an insulating particle. As described above, the conductive particles according to the present invention may have an insulating substance arranged on the outer surface of the conductive portion. However, the conductive particles according to the present invention do not necessarily have an insulating substance.

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

The conductive particle 21 shown in FIG. 3 has a base particle 2, a conductive portion 22, a plurality of core substances 13, and a plurality of insulating substances 14. As a whole, the conductive portion 22 has a first conductive portion 22A on the base particle 2 side and a second conductive portion 22B on the side opposite to the base particle 2 side.

Only the conductive portion is different between the conductive particles 11 and the conductive particles 21. That is, in the conductive particles 11, the conductive portion 12 having a one-layer structure is formed, whereas in the conductive particles 21, the first conductive portion 22A and the second conductive portion 22B having a two-layer structure are formed. ing. The first conductive portion 22A and the second conductive portion 22B are formed as separate conductive portions.

The first conductive portion 22A is arranged on the surface of the base particle 2. The first conductive portion 22A is arranged between the base particle 2 and the second conductive portion 22B. The first conductive portion 22A is in contact with the base particle 2. The second conductive portion 22B is in contact with the first conductive portion 22A. Therefore, the first conductive portion 22A is arranged on the surface of the base particle 2, and the second conductive portion 22B is arranged on the surface of the first conductive portion 22A. The conductive particles 21 have a plurality of protrusions 21a on the conductive surface. The conductive portion 22 has a plurality of protrusions 22a on the outer surface. The first conductive portion 22A has a plurality of protrusions 22Aa on the outer surface. The second conductive portion 22B has a plurality of protrusions 22Ba on the outer surface.

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

The conductive particles 31 shown in FIG. 4 are conductive particles that are not provided with the insulating particles 14 in the conductive particles 21 shown in FIG. The conductive particles 31 are configured in the same manner as the conductive particles 21 except that there are no insulating particles. The conductive particles do not necessarily have an insulating substance.

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

(Base particles)
The material of the base particle is not particularly limited. The material of the base particle may be an organic material or an inorganic material. Examples of the base particle formed from the organic material alone include resin particles and the like. Examples of the base particle formed only of the above-mentioned inorganic material include inorganic particles excluding metal. Examples of the base particle formed by both the organic material and the inorganic material include organic-inorganic hybrid particles. From the viewpoint of further lowering the initial connection resistance and further increasing the conduction reliability, the base material particles are preferably resin particles or organic-inorganic hybrid particles, and more preferably resin particles.

From the viewpoint of further suppressing electrode damage and effectively lowering the connection resistance, it is preferable that the base material particles are not metal particles.

Examples of the organic material include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene and polybutadiene; acrylic resins such as polymethylmethacrylate and polymethylacrylate; polycarbonate, polyamide, phenolformaldehyde resin and melamine. Formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polysulfone, polyphenylene oxide, polyacetal, polyimide, polyamideimide, Examples thereof include polyether ether ketone, polyether sulfone, divinylbenzene polymer, and divinylbenzene copolymer. Examples of the divinylbenzene copolymer and the like include a divinylbenzene-styrene copolymer and a divinylbenzene- (meth) acrylic acid ester copolymer. Since the compression characteristics of the base particle can be easily controlled within a suitable range, the material of the base particle is a polymer obtained by polymerizing one or more polymerizable monomers having an ethylenically unsaturated group. Is preferable.

When the base material particles are obtained by polymerizing a polymerizable monomer having an ethylenically unsaturated group, the polymerizable monomer having an ethylenically unsaturated group is crosslinked with a non-crosslinkable monomer. Examples include sex monomers.

Examples of the non-crosslinkable monomer include styrene monomers such as styrene, α-methylstyrene, and chlorostyrene; vinyl ether compounds such as methylvinyl ether, ethylvinyl ether, and propylvinyl ether; vinyl acetate, vinyl butyrate, and the like. Acid vinyl ester compounds such as vinyl laurate and vinyl stearate; halogen-containing monomers such as vinyl chloride and vinyl fluoride; as (meth) acrylic compounds, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) ) Acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate and other alkyl ( Meta) acrylate compound; oxygen atom-containing (meth) acrylate compound such as 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate, glycidyl (meth) acrylate; Nitrile-containing monomer; Halogen-containing (meth) acrylate compound such as trifluoromethyl (meth) acrylate and pentafluoroethyl (meth) acrylate; As α-olefin compound, olefin such as diisobutylene, isobutylene, linearene, ethylene and propylene Compound: Examples of the conjugated diene compound include isoprene and butadiene.

Examples of the crosslinkable monomer include vinyl monomers such as divinylbenzene, 1,4-dibinyloxybutane, and divinylsulfone as vinyl compounds; and tetramethylolmethanetetra (meth) acrylate as (meth) acrylic compounds. , Polytetramethylene glycol diacrylate, Tetramethylolmethanetri (meth) acrylate, Tetramethylolmethanedi (meth) acrylate, Trimethylolpropanetri (meth) acrylate, Dipentaerythritol hexa (meth) acrylate, Dipentaerythritol penta (meth) ) Acrylic, glycerol tri (meth) acrylate, glycerol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, 1,4-butanediol di Polyfunctional (meth) acrylate compounds such as (meth) acrylate; as allyl compounds, triallyl (iso) cyanurate, triallyl trimellitate, diallylphthalate, diallylacrylamide, diallyl ether; as silane compounds, tetramethoxysilane, tetraethoxysilane , Methyltrimethoxysilane, Methyltriethoxysilane, Ethyltrimethoxysilane, Ethyltriethoxysilane, Isopropyltrimethoxysilane, Isobutyltrimethoxysilane, Cyclohexyltrimethoxysilane, n-hexyltrimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, phenyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diisopropyldimethoxysilane, trimethoxysilylstyrene, γ- (meth) acryloxipropyltrimethoxysilane, 1,3-divinyltetramethyldi Silane alkoxide compounds such as siloxane, methylphenyldimethoxysilane, diphenyldimethoxysilane; vinyltrimethoxysilane, vinyltriethoxysilane, dimethoxymethylvinylsisilane, dimethoxyethylvinylsilane, diethoxymethylvinylsilane, diethoxyethylvinylsilane, ethylmethyldivinylsilane , Methylvinyldimethoxysilane, ethylvinyldimethoxysilane, methylvinyldiethoxysilane, ethylvinyldiethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethi Polymeric double bond-containing silane alkoxides such as rudimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxipropyltrimethoxysilane Cyclic siloxane such as decamethylcyclopentasiloxane; Modified (reactive) silicone oil such as one-terminal modified silicone oil, double-ended silicone oil, side chain type silicone oil; (meth) acrylic acid, maleic acid, maleic anhydride, etc. Examples thereof include a carboxyl group-containing monomer of.

The base material particles can be obtained by polymerizing the polymerizable monomer having an ethylenically unsaturated group. The above polymerization method is not particularly limited, and examples thereof include known methods such as radical polymerization, ionic polymerization, polycondensation (condensation polymerization, polycondensation polymerization), addition condensation, living polymerization, and living radical polymerization. Further, as another polymerization method, suspension polymerization in the presence of a radical polymerization initiator can be mentioned.

Examples of the inorganic material include silica, alumina, barium titanate, zirconia, carbon black, silicate glass, borosilicate glass, lead glass, soda-lime glass and alumina silicate glass.

The base particle may be an organic-inorganic hybrid particle. The base material particles may be core-shell particles. When the base particle is an organic-inorganic hybrid particle, examples of the inorganic substance that is the material of the base particle include silica, alumina, barium titanate, zirconia, and carbon black. It is preferable that the inorganic substance is not a metal. The base particle formed of the silica is not particularly limited, but after hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups to form crosslinked polymer particles, firing is performed if necessary. Examples thereof include substrate particles obtained by carrying out the process. Examples of the organic-inorganic hybrid particles include organic-inorganic hybrid particles formed of a crosslinked alkoxysilyl 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 arranged on the surface of the core. It is preferable that the core is an organic core. It is preferable that the shell is an inorganic shell. The base material particles are preferably organic-inorganic hybrid particles having an organic core and an inorganic shell arranged on the surface of the organic core.

Examples of the organic core material include the organic materials described above.

Examples of the material of the inorganic shell include the above-mentioned inorganic substances as the material of the base particle. The material of the inorganic shell is preferably silica. The inorganic shell is preferably formed by forming a metal alkoxide into a shell-like material by a sol-gel method on the surface of the core and then firing the shell-like material. The metal alkoxide is preferably a silane alkoxide. The inorganic shell is preferably formed of silane alkoxide.

The particle size of the base material particles can be selected in consideration of the particle size of the conductive particles. The particle size of the base particles is preferably 0.1 μm or more, more preferably 1 μm or more. The particle size of the base particles is preferably 1000 μm or less, more preferably 500 μm or less, still more preferably 300 μm or less, still more preferably 50 μm or less, still more preferably 10 μm or less, and particularly preferably 3 μm or less. When the particle size of the base material particles is equal to or larger than the above lower limit, the contact area between the conductive particles and the electrodes becomes large, so that the conduction reliability between the electrodes can be further improved, and the conductive particles are connected via the conductive particles. The connection resistance between the electrodes can be further reduced. Further, when the conductive portion is formed on the surface of the base material particles by electroless plating, it is possible to make it difficult for the agglomerated conductive particles to be formed. When the particle size of the base material particles is not more than the above upper limit, the conductive particles are easily sufficiently compressed, the connection resistance between the electrodes can be further reduced, and the distance between the electrodes can be further reduced. it can.

The particle size of the base particles is particularly preferably 1 μm or more and 3 μm or less. When the particle size of the base material particles is within the range of 1 μm or more and 3 μm or less, it becomes difficult to agglomerate when forming a conductive portion on the surface of the base material particles, and it becomes difficult to form agglomerated conductive particles.

The particle size of the base particles is preferably an average particle size, and preferably a number average particle size. As for the particle size of the base particle, 50 arbitrary base particles are observed with an electron microscope or an optical microscope, the average value of the particle size of each base particle is calculated, or a particle size distribution measuring device is used. Is required. In observation with an electron microscope or an optical microscope, the particle size of each substrate particle is determined as the particle size in a circle-equivalent diameter. In observation with an electron microscope or an optical microscope, the average particle diameter of any 50 substrate particles in a circle-equivalent diameter is substantially equal to the average particle diameter in a sphere-equivalent diameter. In the particle size distribution measuring device, the particle size of each base particle is determined as the particle size in the equivalent sphere diameter. The average particle size of the base particles is preferably calculated using a particle size distribution measuring device. From the viewpoint of high measurement accuracy, the particle size distribution measuring device is preferably a laser diffraction type particle size distribution measuring device. When measuring the particle size of the base material particles in the conductive particles, for example, the measurement can be performed as follows.

An embedded resin for conducting a conductive particle inspection is prepared by adding and dispersing the conductive particles to "Technobit 4000" manufactured by Kulzer so that the content of the conductive particles is 30% by weight. A cross section of the conductive particles is cut out using an ion milling device (“IM4000” manufactured by Hitachi High-Technologies Corporation) so as to pass near the center of the conductive particles dispersed in the embedded resin for inspection. Then, using a field emission scanning electron microscope (FE-SEM), the image magnification is set to 25000 times, 50 conductive particles are randomly selected, and the base particles of each conductive particle are observed. To do. The particle size of the base material particles in each conductive particle is measured, and they are arithmetically averaged to obtain the particle size of the base material particles.

(Conductive part)
The conductive particles according to the present invention include base particles and conductive portions arranged on the surface of the base particles. The conductive portion preferably contains a metal. In order to control the amount of saturation magnetization in a suitable range, an appropriate metal constituting the conductive portion is used.

The metals constituting the conductive portion include gold, silver, palladium, copper, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, tarium, germanium, cadmium, and the like. Examples thereof include silicon, tungsten, molybdenum and alloys thereof. Examples of the metal constituting the conductive portion include tin-doped indium oxide (ITO) and solder. Only one kind of metal constituting the conductive portion may be used, or two or more kinds may be used in combination.

From the viewpoint of more easily controlling the saturated magnetization amount within a suitable range, it is preferable that the conductive portion contains nickel, cobalt or iron. In this case, the conductive layer may contain only one of nickel, cobalt and iron, or may contain two or more. The conductive portion may or may not contain nickel. The conductive portion preferably contains at least two of nickel, cobalt and iron. The conductive portion may or may not contain cobalt. The conductive portion may or may not contain iron.

From the viewpoint of more easily controlling the saturated magnetization amount to a suitable range, the total content of nickel, cobalt and iron in 100% by weight of the conductive portion is preferably 90% by weight or more, more preferably 95% by weight. % Or more, more preferably 98% by weight or more, and preferably 100% by weight or less.

From the viewpoint of more easily controlling the saturated magnetization amount to a suitable range, when the conductive portion contains nickel, the nickel content is preferably 5% by weight or more, more preferably 5% by weight or more, based on 100% by weight of the conductive portion. It is preferably 50% by weight or more, more preferably 98% by weight or more, and preferably 100% by weight or less.

From the viewpoint of more easily controlling the saturated magnetization amount to a suitable range, when the conductive portion contains cobalt, the cobalt content is preferably 5% by weight or more in 100% by weight of the conductive portion. It is preferably 50% by weight or more, more preferably 98% by weight or more, and preferably 100% by weight or less.

From the viewpoint of more easily controlling the saturated magnetization amount to a suitable range, when the conductive portion contains iron, the iron content is preferably 5% by weight or more in 100% by weight of the conductive portion. It is preferably 50% by weight or more, more preferably 98% by weight or more, and preferably 100% by weight or less.

From the viewpoint of more easily controlling the saturated magnetization amount to a suitable range, when the conductive portion contains at least two of nickel, cobalt and iron, the content of nickel in 100% by weight of the conductive portion , The content of one of the cobalt content and the iron content is defined as the content (A). From the viewpoint of more easily controlling the saturated magnetization amount to a suitable range, the content (A) is preferably 51% by weight or more, more preferably 55% by weight or more, still more preferably 60% by weight or more. Yes, preferably less than 100% by weight, more preferably 99% by weight or less. The content (A) is the highest of the nickel content, the cobalt content, and the iron content in the 100% by weight of the conductive portion.

In addition, hydroxyl groups are often present on the surface of the conductive portion due to oxidation. Generally, a hydroxyl group is present on the surface of a conductive portion formed of nickel due to oxidation. An insulating substance can be arranged on the surface of the conductive portion having such a hydroxyl group (the surface of the conductive particles) via a chemical bond.

The conductive portion may be formed by one layer. The conductive portion 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, it is preferable that the metal constituting the outermost layer contains nickel, cobalt or iron.

The method of forming the conductive portion on the surface of the base particle is not particularly limited. Examples of the method for forming the conductive portion include a method by electroless plating, a method by electroplating, a method by physical collision, a method by mechanochemical reaction, a method by physical vapor deposition or physical adsorption, and a metal powder or metal powder. Examples thereof include a method of coating the surface of the substrate particles with a paste containing the binder and the binder. The method for forming the conductive portion is preferably a method by electroless plating, electroplating or physical collision. Examples of the method by physical vapor deposition include methods such as vacuum vapor deposition, ion plating, and ion sputtering. Further, as the method by the above physical collision, a sheeter composer (manufactured by Tokuju Kosakusho Co., Ltd.) or the like is 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, still more preferably 0.3 μm or less. The thickness of the conductive portion is the thickness of the entire conductive portion when the conductive portion has multiple layers. When the thickness of the conductive portion is at least the above lower limit and at least the above upper limit, sufficient conductivity can be obtained, and the conductive particles are not too hard and the conductive particles are sufficiently deformed at the time of connection between the electrodes. Can be made to.

From the viewpoint of more easily controlling the amount of saturation magnetization to a suitable range, the thickness of the conductive portion is preferably 0.01 μm or more, more preferably 0.05 μm or more, preferably 5 μm or less, more preferably. Is 1 μm or less.

When the conductive portion is formed of a plurality of layers, the thickness of the conductive portion of the outermost layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, preferably 0.5 μm or less, more preferably. Is 0.1 μm or less. When the thickness of the conductive portion of the outermost layer is equal to or higher than the lower limit and lower than the upper limit, the coating by the conductive portion of the outermost layer becomes uniform, the corrosion resistance becomes sufficiently high, and the connection resistance between the electrodes is sufficient. Can be lowered to.

The thickness of the conductive portion can be measured by observing the cross section of the conductive particles using, for example, a transmission electron microscope (TEM). Regarding the thickness of the conductive portion, it is preferable to calculate the average value of the thickness of any of the conductive portions at five points as the thickness of the conductive portion of one conductive particle, and the average value of the thickness of the entire conductive portion is one. It is more preferable to calculate as the thickness of the conductive portion of the conductive particles. The thickness of the conductive portion is preferably obtained by calculating the average value of the thickness of the conductive portion of each conductive particle for 10 arbitrary conductive particles.

The contents of nickel, cobalt, and iron are determined by a high-frequency inductively coupled plasma emission spectroscopic analyzer (“ICP-AES” manufactured by Horiba, Ltd.) or a fluorescent X-ray analyzer (“EDX-800HS” manufactured by Shimadzu Corporation). ) Etc. can be used for measurement.

(Core material and protrusions)
The conductive particles preferably have protrusions on the outer surface of the conductive portion. It is preferable that the number of the protrusions is plurality. An oxide film is often formed on the surface of the electrode connected by the conductive particles. When conductive particles having protrusions on the surface of the conductive portion are used, the oxide film can be effectively removed by the protrusions by arranging the conductive particles between the electrodes and crimping them. Therefore, the electrodes and the conductive portion come into contact with each other more reliably, and the connection resistance between the electrodes becomes even lower. Further, when the conductive particles include an insulating substance, or when the conductive particles are dispersed in a binder resin and used as a conductive material, the protrusions of the conductive particles provide insulation between the conductive particles and the electrode. The sex substance or the binder resin can be eliminated more effectively. Therefore, the connection resistance between the electrodes can be further reduced.

It is preferable that the conductive particles include a plurality of core substances in which the surface of the conductive portion is raised so as to form the plurality of protrusions in the conductive portion.

As a method of forming the above-mentioned protrusions, a method of forming a conductive portion by electroless plating after adhering a core substance to the surface of the base material particles, and a method of forming a conductive portion by electroless plating on the surface of the base material particles. After that, a method of adhering a core substance and further forming a conductive portion by electroless plating can be mentioned. Further, the core material may not be used to form the protrusions.

Examples of other methods for forming the protrusions include a method of adding a core substance in the middle of forming a conductive portion on the surface of the base particle. Further, in order to form protrusions, a conductive portion is formed on the base material particles by electroless plating without using the above-mentioned core substance, and then plating is deposited in a protrusion shape on the surface of the conductive portion, and further electroless plating is performed. You may use a method of forming a conductive portion by the above method.

As a method of adhering the core substance to the surface of the base particle, the core substance is added to the dispersion liquid of the base particle, and the core substance is accumulated and adhered to the surface of the base particle by van der Waals force. Examples thereof include a method in which a core substance is added to a container containing the base material particles, and the core substance is adhered to the surface of the base material particles by a mechanical action such as rotation of the container. From the viewpoint of controlling the amount of the core substance to be adhered, the method of adhering the core substance to the surface of the base material particles is a method of accumulating and adhering the core substance to the surface of the base material particles in the dispersion liquid. preferable.

Examples of the substance constituting the core substance include a conductive substance and a non-conductive substance. Examples of the conductive substance include metals, metal oxides, conductive non-metals such as graphite, and conductive polymers. Examples of the conductive polymer include polyacetylene and the like. Examples of the non-conductive substance include silica, alumina and zirconia. From the viewpoint of removing the oxide film more effectively, the core material is preferably hard. From the viewpoint of further effectively lowering the connection resistance between the electrodes, the core material is preferably a metal.

The metal is not particularly limited. Examples of the metals include metals such as gold, silver, copper, platinum, zinc, iron, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium and cadmium, and tin-lead alloys. Examples thereof include alloys composed of two or more kinds of metals such as tin-copper alloy, tin-silver alloy, tin-lead-silver alloy and tungsten carbide. From the viewpoint of further effectively lowering the connection resistance between the electrodes, the metal is preferably nickel, copper, silver or gold. The metal may be the same as or different from the metal constituting the conductive portion (conductive layer).

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

The particle size of the core substance 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. When the particle size of the core substance is not less than the above lower limit and not more than the upper limit, the connection resistance between the electrodes can be further effectively reduced.

The particle size of the core material is preferably an average particle size, and more preferably a number average particle size. The particle size of the core substance can be obtained by observing 50 arbitrary core substances with an electron microscope or an optical microscope, calculating the average value of the particle size of each core substance, or using a particle size distribution measuring device. In observation with an electron microscope or an optical microscope, the particle size of each core substance is determined as the particle size in a circle-equivalent diameter. In observation with an electron microscope or an optical microscope, the average particle diameter of any 50 core materials in the equivalent circle diameter is substantially equal to the average particle diameter in the equivalent diameter of the sphere. In the particle size distribution measuring device, the particle size of each core substance is obtained as the particle size in the equivalent diameter of a sphere. The average particle size of the core material is preferably calculated using a particle size distribution measuring device. From the viewpoint of high measurement accuracy, the particle size distribution measuring device is preferably a laser diffraction type particle size distribution measuring device.

From the viewpoint of further lowering the initial connection resistance and further enhancing the conduction reliability under high temperature and high humidity, the surface area of the portion having the protrusion is preferably 100% of the total surface area of the outer surface of the conductive portion. It is 25% or more, more preferably 30% or more, still more preferably 50% or more. The surface area of the portion having the protrusions may be 95% or less, 90% or less, or 80% or less.

The number of the protrusions per one conductive particle is preferably 3 or more, and more preferably 5 or more. The upper limit of the number of the protrusions is not particularly limited. The upper limit of the number of protrusions can be appropriately selected in consideration of the particle size of the conductive particles and the like. When the number of the protrusions is at least the above lower limit, the connection resistance between the electrodes can be further effectively reduced.

The number of the protrusions can be calculated by observing arbitrary conductive particles with an electron microscope or an optical microscope. The number of protrusions is preferably determined by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating the average value of the number of protrusions in each conductive particle.

The height of the protrusion 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. When the height of the protrusion is equal to or higher than the lower limit and lower than the upper limit, the connection resistance between the electrodes can be further effectively reduced.

The height of the protrusions can be calculated by observing the protrusions on any conductive particle with an electron microscope or an optical microscope. The height of the protrusions is preferably calculated by calculating the average value of the heights of all the protrusions per conductive particle as the height of the protrusions of one conductive particle. It is preferable that the height of the protrusions is obtained by calculating the average value of the heights of the protrusions of each conductive particle for 50 arbitrary conductive particles.

(Insulating substance)
From the viewpoint of further enhancing the conductivity, the conductive particles do not have to include an insulating substance arranged on the outer surface of the conductive portion. From the viewpoint of further enhancing the insulation reliability, it is preferable that the conductive particles include an insulating substance arranged on the outer surface of the conductive portion. In this case, if the conductive particles are used for the connection between the electrodes, a short circuit between adjacent electrodes can be prevented more effectively. Specifically, when a plurality of conductive particles come into contact with each other, an insulating substance exists between the plurality of electrodes, so that it is possible to prevent a short circuit between the electrodes adjacent to each other in the lateral direction rather than between the upper and lower electrodes. By pressurizing the conductive particles with the two electrodes at the time of connection between the electrodes, the insulating substance between the conductive portion of the conductive particles and the electrodes can be easily removed. Further, in the case of the conductive particles having protrusions on the outer surface of the conductive portion, the insulating substance between the conductive portion of the conductive portion and the electrode can be more easily removed.

Examples of the insulating substance include an insulating layer and insulating particles. The insulating substance is preferably insulating particles because the insulating substance can be more easily removed during crimping between the electrodes.

Examples of the material of the insulating substance include the above-mentioned organic material, the above-mentioned inorganic material, and the above-mentioned inorganic substance as the material of the base particle. The material of the insulating substance is preferably the organic material described above.

Other materials of the insulating substance include polyolefin compounds, (meth) acrylate polymers, (meth) acrylate copolymers, block polymers, thermoplastic resins, crosslinked products of thermoplastic resins, thermosetting resins and water-soluble materials. Examples include resin. As the material of the insulating substance, only one kind 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-acrylic acid ester 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-acrylic acid ester copolymer, SB type styrene-butadiene block copolymer, SBS type styrene-butadiene block copolymer, and hydrogenated products thereof. Examples of the thermoplastic resin include vinyl polymers and vinyl copolymers. Examples of the thermosetting resin include epoxy resin, phenol resin, melamine resin and the like. Examples of the crosslinked product of the thermoplastic resin include the introduction of polyethylene glycol methacrylate, alkoxylated trimethylolpropane methacrylate, alkoxylated pentaerythritol methacrylate and the like. Examples of the water-soluble resin include polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinylpyrrolidone, polyethylene oxide, methyl cellulose and the like. Further, a chain transfer agent may be used to adjust the degree of polymerization. Examples of the chain transfer agent include thiols and carbon tetrachloride.

Examples of the method of arranging the insulating substance on the surface of the conductive portion include a chemical method and a physical or mechanical method. Examples of the chemical method include an interfacial polymerization method, a suspension polymerization method in the presence of particles, and an emulsion polymerization method. Examples of the physical or mechanical method include spray drying, hybridization, electrostatic adhesion method, spraying method, dipping and vacuum deposition method. From the viewpoint of further effectively enhancing the insulation reliability and the conduction reliability when the electrodes are electrically connected, the method of arranging the insulating substance on the surface of the conductive portion is a physical method. It is preferable to have.

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

When the insulating substance is an insulating particle, the particle size of the insulating particle can be appropriately selected depending on the particle size of the conductive particle, the use of the conductive particle, and the like. The particle size of the insulating particles is preferably 10 nm or more, more preferably 100 nm or more, further preferably 300 nm or more, particularly preferably 500 nm or more, preferably 4000 nm or less, more preferably 2000 nm or less, still more preferably 1500 nm or less. , Especially preferably 1000 nm or less. When the particle size of the insulating particles is at least the above lower limit, it becomes difficult for the conductive portions of the plurality of conductive particles to come into contact with each other when the conductive particles are dispersed in the binder resin. When the particle size of the insulating particles is not more than the above upper limit, it is not necessary to increase the pressure too much in order to eliminate the insulating particles between the electrodes and the conductive particles when connecting the electrodes, and the temperature is high. There is no need to heat it.

The particle size of the insulating particles is preferably an average particle size, and preferably a number average particle size. For the particle size of the insulating particles, observe 50 arbitrary insulating particles with an electron microscope or an optical microscope, calculate the average value of the particle size of each insulating particle, or use a particle size distribution measuring device. Desired. In observation with an electron microscope or an optical microscope, the particle size of each insulating particle is determined as the particle size in a circle-equivalent diameter. In observation with an electron microscope or an optical microscope, the average particle diameter of any 50 insulating particles in a circle-equivalent diameter is substantially equal to the average particle diameter in a sphere-equivalent diameter. In the particle size distribution measuring device, the particle size of each insulating particle is obtained as the particle size in the equivalent diameter of a sphere. The average particle size of the insulating particles is preferably calculated using a particle size distribution measuring device. When measuring the particle size of the insulating particles in the conductive particles, for example, the measurement can be performed as follows.

Conductive particles are added to "Technobit 4000" manufactured by Kulzer so as to have a content of 30% by weight and dispersed to prepare an embedded resin for conducting conductive particle inspection. A cross section of the conductive particles is cut out using an ion milling device (“IM4000” manufactured by Hitachi High-Technologies Corporation) so as to pass near the center of the dispersed conductive particles in the embedded resin for inspection. Then, using a field emission scanning electron microscope (FE-SEM), the image magnification was set to 50,000 times, 50 conductive particles were randomly selected, and the insulating particles of each conductive particle were observed. To do. The particle size of the insulating particles in each conductive particle is measured, and they are arithmetically averaged to obtain the particle size of the insulating particles.

The ratio of the particle size of the conductive particles to the particle size of the insulating particles (particle size of the conductive particles / particle size of the insulating particles) is preferably 4 or more, more preferably 8 or more, and preferably 8. It is 200 or less, more preferably 100 or less. When the above ratio (particle size of conductive particles / particle size of insulating particles) is equal to or more than the above lower limit and less than or equal to the above upper limit, the insulation reliability and conduction reliability are further improved when the electrodes are electrically connected. It can be enhanced more effectively.

(Conductive material)
The conductive material according to the present invention includes the above-mentioned conductive particles and a binder resin. The conductive particles are preferably dispersed in the binder resin and used, and preferably dispersed in the binder resin and used as the 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 above-mentioned conductive particles are used in the above-mentioned conductive material, the connection resistance between the electrodes can be lowered more effectively, and the occurrence of aggregation between the conductive particles can be further effectively suppressed. be able to. Since the above-mentioned conductive particles are used in the above-mentioned conductive material, the insulation reliability between the electrodes can be further effectively enhanced.

The binder resin is not particularly limited. As the 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 curable component include a photocurable component and a thermosetting component. 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 binder resin may be used, or two or more kinds may be used in combination.

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

From the viewpoint of improving the placement accuracy of the conductive particles and effectively lowering the connection resistance, the binder resin preferably contains a thermosetting compound having a glycidyl group or a (meth) acryloyl group. The thermosetting compound may have a glycidyl group or a (meth) acryloyl group.

In addition to the conductive particles and the binder resin, the conductive material includes, for example, a filler, a bulking agent, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, and a photostabilizer. It may contain various additives such as an agent, an ultraviolet absorber, a lubricant, an antistatic agent and a flame retardant.

As a method for dispersing the conductive particles in the binder resin, a conventionally known dispersion method can be used and is not particularly limited. Examples of the method for dispersing the conductive particles in the binder resin include the following methods. A method in which the conductive particles are added to the binder resin and then kneaded and dispersed with a planetary mixer or the like. A method in which the conductive particles are uniformly dispersed in water or an organic solvent using a homogenizer or the like, added to the binder resin, and kneaded and dispersed by a planetary mixer or the like. A method in which the binder resin is diluted with water or an organic solvent, the conductive particles are added, and the binder resin is kneaded and dispersed with a planetary mixer or the like.

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. When the viscosity of the conductive material at 25 ° C. is equal to or higher than the lower limit and lower than the upper limit, the insulation reliability between the electrodes can be further effectively enhanced, and the conduction reliability between the electrodes is further effective. Can be enhanced to. The viscosity (η25) can be appropriately adjusted depending on the type and amount of the compounding components.

The viscosity (η25) can be measured at 25 ° C. and 5 rpm using, for example, an E-type viscometer (“TVE22L” manufactured by Toki Sangyo Co., Ltd.).

The conductive material according to the present invention can be used as a conductive paste, a conductive film, or the like. When the conductive material according to the present invention is a conductive film, a film containing no conductive particles may be laminated on the conductive film containing the 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, still more preferably 50% by weight or more, and particularly preferably 70% by weight or more. Is 99.99% by weight or less, more preferably 99.9% by weight or less. When the content of the binder resin is not less than the above lower limit and not more than the above upper limit, the conductive particles are efficiently arranged between the electrodes, and the connection reliability of the connection target member connected by the conductive material is further enhanced. Can be done.

Further, a conductive material in which the conductive particles are arranged at a specific position can be produced by collecting the conductive particles at an arbitrary position by applying a magnetic field or a magnetic force X when mixing the binder resin and the particles.

The step of applying the magnetic field or the magnetic force may be performed after mixing the binder resin and the particles.

The content of the conductive particles in 100% by weight of the conductive material is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, preferably 80% by weight or less, more preferably 60% by weight. % Or less, more preferably 40% by weight or less, particularly preferably 20% by weight or less, and most preferably 10% by weight or less. When the content of the conductive particles is not less than the above lower limit and not more than the above upper limit, the connection resistance between the electrodes can be further effectively lowered. When the content of the conductive particles is not less than the above lower limit and not more than the above upper limit, the conduction reliability and the insulation reliability between the electrodes can be further improved.

(Connecting structure and manufacturing method of connecting structure)
The connection structure according to the present invention includes a first connection target member having a first electrode on the surface, a second connection target member having a second electrode on the surface, the first connection target member, and the above. It includes a connecting portion that connects to the second connection target member. In the connection structure according to the present invention, the material of the connection portion is the above-mentioned conductive particles or a conductive material containing the above-mentioned conductive particles and a binder resin. In the connection structure according to the present invention, the first electrode and the second electrode are electrically connected by the conductive particles.

The connection structure includes a step of arranging the conductive particles or the conductive material between the first connection target member and the second connection target member, and a step of conducting a conductive connection by thermocompression bonding. Can be obtained through. When the conductive particles have the insulating substance, it is preferable that the insulating substance is desorbed from the conductive particles at the time of thermocompression bonding.

When the conductive particles are used alone, the connecting portion itself is the conductive particles. That is, the first connection target member and the second connection target member are connected by the conductive particles. The conductive material used to obtain the connection structure is preferably an anisotropic conductive material.

In the method for producing a connection structure according to the present invention, the above-mentioned conductive particles are arranged on the surface of a first connection target member having a first electrode on the surface, or the above-mentioned conductive particles and a binder resin are used. The first placement step of arranging the conductive material containing the above is provided. The method for manufacturing a connection structure according to the present invention is a second connection target having a second electrode on the surface opposite to the first connection target member side of the conductive particles or the conductive material. A second placement step of arranging the members is provided. The method for manufacturing a connection structure according to the present invention includes a step of applying a magnetic field or a magnetic force before or after the second arrangement step. In the method for manufacturing a connection structure according to the present invention, a connection structure in which the first electrode and the second electrode are electrically connected by the conductive particles is obtained.

FIG. 5 is a front sectional view schematically showing a connection structure using conductive particles according to the first embodiment of the present invention.

The connection structure 51 shown in FIG. 5 connects a first connection target member 52, a second connection target member 53, and a connection portion 54 connecting the first and second connection target members 52 and 53. Be prepared. The connecting portion 54 is formed by curing a conductive material containing the conductive particles 1. In FIG. 5, the conductive particles 1 are shown schematicly for convenience of illustration. Instead of the conductive particles 1, other conductive particles such as conductive particles 11 and 21 may be used.

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

The connection structure 51 can be obtained, for example, as follows.

A first connection target member 52 having the first electrode 52a on the surface (upper surface) is prepared. As shown in FIG. 6A, the conductive material 61 is arranged on the surface provided with the first electrode 52a of the first connection target member 52 (first arrangement step). The conductive material 61 contains the conductive particles 1. After the arrangement of the conductive material 61, the conductive particles 1 are arranged both on the first electrode 52a (line) and on the region (space) where the first electrode 52a is not formed.

The method of arranging the conductive material is not particularly limited, and examples thereof include coating with a dispenser, screen printing, and ejection with an inkjet device.

Further, a second connection target member 53 having the second electrode 53a on the front surface (lower surface) is prepared. Next, as shown in FIG. 6B, in the conductive material 61 on the surface of the first connection target member 52, what is the first connection target member 52 side of the conductive material 61 (or the conductive particles 1)? The second connection target member 53 is arranged on the surface on the opposite side (second arrangement step). The second connection target member 53 is arranged on the surface of the conductive material 61 from the second electrode 53a side. At this time, the first electrode 52a and the second electrode 53a are opposed to each other.

As shown in FIG. 6C, a magnetic field or a magnetic force X is applied to the second arrangement step. It is preferable to apply a magnetic field or a magnetic force to the first electrode 52a portion. It is preferable to apply a magnetic field or a magnetic force at the second electrode 53a portion. By applying a magnetic field or magnetic force, the conductive particles 1 are collected on the first electrode 52a. Further, by applying a magnetic field or a magnetic force, the conductive particles 1 are gathered between the first electrode 52a and the second electrode 53a. As a result, the number of conductive particles 1 arranged between the first electrode 52a and the second electrode 53a increases.

The connection structure 51 shown in FIG. 5 can be obtained by performing the thermocompression bonding step from the state shown in FIG. 6 (c).

Alternatively, the connection structure 51 can be obtained, for example, as follows.

A first connection target member 52 having the first electrode 52a on the surface (upper surface) is prepared. As shown in FIG. 7A, the conductive material 61 is arranged on the surface provided with the first electrode 52a of the first connection target member 52 (first arrangement step). The conductive material 61 contains the conductive particles 1. After the arrangement of the conductive material 61, the conductive particles 1 are arranged both on the first electrode 52a (line) and on the region (space) where the first electrode 52a is not formed.

As shown in FIG. 7B, a magnetic field or a magnetic force X is applied to the first arrangement step. By applying a magnetic field or magnetic force, the conductive particles 1 are collected on the first electrode 52a. As a result, the number of conductive particles 1 arranged on the first electrode 52a increases.

Further, a second connection target member 53 having the second electrode 53a on the front surface (lower surface) is prepared. Next, as shown in FIG. 7C, in the conductive material 61 on the surface of the first connection target member 52, what is the first connection target member 52 side of the conductive material 61 (or the conductive particles 1)? The second connection target member 53 is arranged on the surface on the opposite side (second arrangement step). The second connection target member 53 is arranged on the surface of the conductive material 61 from the second electrode 53a side. At this time, the first electrode 52a and the second electrode 53a are opposed to each other.

The connection structure 51 shown in FIG. 5 can be obtained by performing the thermocompression bonding step from the state shown in FIG. 7 (c).

The step of applying the magnetic field or the magnetic force may be performed before the first placement step or before the second placement step, or after the second placement step. From the viewpoint of further improving the placement accuracy of the conductive particles, the step of applying the magnetic field or the magnetic force is preferably performed before the first placement step or after the second placement step.

It is preferable that the thermocompression bonding step is performed after the second arrangement step and after the step of applying the magnetic field or the magnetic force. By thermocompression bonding the laminate of the first connection target member, the conductive particles or the conductive material, and the second connection target member, a connection structure having excellent connection reliability can be obtained.

The thermocompression bonding pressure 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 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. When the pressure and temperature of the thermocompression bonding are at least the above lower limit and at least the above upper limit, the conduction reliability and insulation reliability between the electrodes can be further improved. Further, when the conductive particles have the insulating particles, the insulating particles can be easily separated from the surface of the conductive particles at the time of conductive connection.

When the conductive particles have the insulating particles, they are present between the conductive particles and the first electrode and the second electrode when the laminate is heated and pressurized. The above insulating particles can be eliminated. For example, during the heating and pressurization, the insulating particles existing between the conductive particles and the first electrode and the second electrode are released from the surface of the conductive particles. Easy to detach. During the heating and pressurization, some of the insulating particles may be separated from the surface of the conductive particles, and the surface of the conductive portion may be partially exposed. When the exposed surface of the conductive portion comes into contact with the first electrode and the second electrode, the first electrode and the second electrode are electrically connected via the conductive particles. can do.

The first connection target member and the second connection target member are not particularly limited. Specific examples of the first connection target member and the second connection target member include electronic components such as semiconductor chips, semiconductor packages, LED chips, LED packages, capacitors and diodes, resin films, printed circuit boards, and flexible devices. Examples thereof include electronic components such as printed circuit boards, flexible flat cables, rigid flexible boards, glass epoxy boards, and circuit boards such as glass boards. The first connection target member and the second connection target member are preferably electronic components.

Examples of the electrode provided on the connection target member include a gold electrode, a nickel electrode, a tin electrode, an aluminum electrode, a copper electrode, a molybdenum electrode, a silver electrode, a SUS electrode, and a metal electrode such as a tungsten electrode. When the connection target member is a flexible printed substrate, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, a silver electrode, or a copper electrode. When the member to be connected is a glass substrate, the electrodes are preferably aluminum electrodes, copper electrodes, molybdenum electrodes, silver electrodes or tungsten electrodes. When the electrode is an aluminum electrode, it may be an electrode formed only of aluminum, or an electrode in which an aluminum layer is laminated on the surface of a metal oxide layer. Examples of the material of the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal element include Sn, Al and Ga.

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

(Example 1)
(1) Preparation of Conductive Particles Divinylbenzene copolymer resin particles (“Micropearl SP-203, particle size 3 μm” manufactured by Sekisui Chemical Co., Ltd.) were prepared as base particle particles A.

10 parts by weight of the base particle A was dispersed in 100 parts by weight of an alkaline solution containing 5% by weight of the palladium catalyst solution by an ultrasonic disperser, and then the base particle A was taken out by filtering the solution. Next, the base particle A was added to 100 parts by weight of a 1% by weight solution of dimethylamine borane to activate the surface of the base particle A. The surface-activated substrate particles A were thoroughly washed with water, and then added to 500 parts by weight of distilled water and dispersed to obtain a suspension (1A).

1 part by weight of a metallic nickel slurry (average particle size 150 nm) is added to the suspension (1A) over 3 minutes to obtain a particle mixed suspension (1B) containing base particle A to which a core substance is attached. It was.

Further, a nickel plating solution (2) (pH 10) containing nickel sulfamate 50 g / L, glycine 70 g / L, boric acid 30 g / L and hydradium sulfate 300 g / L was prepared.

While stirring the suspension (1B) at 80 ° C., the nickel plating solution (2) was gradually added dropwise to perform electroless pure nickel plating. Then, the mixture was stirred until the pH became stable, and it was confirmed that the foaming of hydrogen stopped, and a suspension (3) after electroless pure nickel plating was obtained.

Then, by filtering the suspension (3), the particles were taken out, washed with water, and dried. Conductive particles in which a conductive portion (thickness 51 nm) of high-purity Ni was arranged on the outer surface of the base particles were obtained. The conductive particles include metallic nickel particles as a core material.

(Example 2)
Conductive particles were obtained in the same manner as in Example 1 except that the thickness of the conductive layer was changed from 51 nm to 80 nm.

(Example 3)
The same suspension (1B) as in Example 1 was placed in a solution containing 25 g / L of nickel sulfate, 15 ppm of thallium nitrate and 10 ppm of bismuth nitrate to obtain a particle mixture (4).

Further, a boron-containing nickel plating solution (5) (pH 8.0) containing 100 g / L of nickel sulfate, 30 g / L of dimethylamine borane, 15 g / L of sodium citrate, 25 ppm of thallium nitrate, and 10 ppm of bismuth nitrate was prepared.

The boron-containing nickel plating solution (5) was gradually added dropwise while stirring the particle mixture (4) at 60 ° C. to perform electroless nickel plating. Then, the mixture was stirred until the pH became stable, and it was confirmed that the foaming stopped, and a suspension (6) after electroless boron-containing nickel plating was obtained.

Then, the suspension (6) was filtered, washed with water, added to 500 parts by weight of distilled water, and dispersed to obtain a suspension (7) of boron-containing nickel-plated particles.

Further, by performing electroless pure nickel plating in the same manner as in Example 1, a conductive portion of boron-containing Ni (thickness 19 nm) is arranged on the surface of the base particle, and a conductive portion of high-purity Ni (thickness 19 nm) is further arranged on the outer surface. Conductive particles having a thickness of 51 nm) were obtained.

(Example 4)
Example 1 except that electroless nickel plating was performed using the suspension (1A) to obtain conductive particles having no core material, and the thickness of the conductive layer was changed from 51 nm to 55 nm. In the same manner as above, conductive particles were obtained.

(Example 5)
Conductive particles were obtained in the same manner as in Example 1 except that the metallic nickel particle slurry was changed to titanium oxide particle slurry (average particle size 150 nm) and the thickness of the conductive layer was changed from 51 nm to 52 nm. .. The conductive particles include titanium oxide particles as a core substance.

(Example 6)
Conductive particles were obtained in the same manner as in Example 1 except that the metal nickel particle slurry was changed to an alumina particle slurry (average particle size 150 nm). The conductive particles include alumina particles as a core material.

(Example 7)
The same suspension (1B) as in Example 1 was placed in a solution containing 20 g / L of cobalt sulfate and 20 g / L of sodium citrate to obtain a particle mixture (9).

Further, a boron-containing cobalt plating solution (10) (pH 8.0) containing 70 g / L of cobalt sulfate, 50 g / L of dimethylamine borane, and 60 g / L of sodium citrate was prepared.

The boron-containing cobalt plating solution (10) was gradually added dropwise while stirring the particle mixture (9) at 60 ° C. to perform electroless cobalt plating. Then, the mixture was stirred until the pH became stable, and it was confirmed that the foaming stopped, and a suspension (11) after electroless boron-containing cobalt plating was obtained.

Then, the suspension (11) was filtered, washed with water, and dried to obtain conductive particles in which a conductive portion of Co-B (thickness 55 nm) was arranged on the outer surface of the base particles.

(Example 8)
The same suspension (1B) as in Example 1 was placed in a solution containing 20 g / L of nickel sulfate and 20 g / L of sodium citrate to obtain a particle mixture (12).

A boron-containing nickel-cobalt plating solution (13) (pH 9.0) containing 70 g / L of nickel sulfate, 70 g / L of cobalt sulfate, 70 g / L of dimethylamine borane, 10 g / L of sodium citrate, and 60 g / L of sodium gluconate. I prepared.

The boron-containing nickel-cobalt plating solution (13) was gradually added dropwise while stirring the particle mixture (12) at 60 ° C. to perform electroless nickel-cobalt plating. Then, the mixture was stirred until the pH became stable, and it was confirmed that the foaming stopped, and a suspension (14) after electroless boron-containing nickel-cobalt plating was obtained.

Then, the suspension (14) was filtered, washed with water, and dried to obtain conductive particles in which a conductive portion (thickness 62 nm) of Ni—Co-B was arranged on the outer surface of the base particles.

(Example 9)
The same suspension (1B) as in Example 1 was placed in a solution containing 20 g / L of nickel sulfate and 20 g / L of sodium citrate to obtain a particle mixture (15).

A boron-containing nickel iron plating solution (16) (pH 10.0) containing nickel sulfate 70 g / L, iron sulfate 40 g / L, dimethylamine borane 70 g / L, sodium citrate 10 g / L, and sodium gluconate 100 g / L. I prepared.

The boron-containing nickel-iron plating solution (16) was gradually added dropwise while stirring the particle mixture (15) at 60 ° C. to perform electroless boron-containing nickel-iron plating. Then, the mixture was stirred until the pH became stable, and it was confirmed that the foaming stopped, and a suspension (17) after electroless boron-containing nickel-iron plating was obtained.

Then, the suspension (17) was filtered, washed with water, and dried to obtain conductive particles in which a conductive portion (thickness 54 nm) of Ni-Fe-B was arranged on the outer surface of the base particles.

(Example 10)
The same suspension (1B) as in Example 1 was placed in a solution containing 20 g / L of cobalt sulfate and 20 g / L of sodium citrate to obtain a particle mixture (18).

A boron-containing cobalt iron plating solution containing 80 g / L of cobalt sulfate, 30 g / L of iron sulfate, 70 g / L of dimethylamine borane, 10 g / L of sodium citrate, and 100 g / L of sodium gluconate (19) (pH 9.0). I prepared.

The boron-containing cobalt iron plating solution (19) was gradually added dropwise while stirring the particle mixture (18) at 60 ° C. to perform electroless boron-containing cobalt iron plating. Then, the mixture was stirred until the pH became stable, and it was confirmed that the foaming stopped, and a suspension (20) after electroless boron-containing cobalt iron plating was obtained.

Then, the suspension (20) was filtered, washed with water, and dried to obtain conductive particles in which a conductive portion (thickness 51 nm) of Co-Fe-B was arranged on the outer surface of the substrate particles.

(Example 11)
(1) Preparation of Silicone Oligomer In a 100 ml separable flask placed in a warm bath, 1 part by weight of 1,3-divinyltetramethyldisiloxane and 20 parts by weight of a 0.5% by weight p-toluenesulfonic acid aqueous solution were placed. I put it in. After stirring at 40 ° C. for 1 hour, 0.05 parts by weight of sodium hydrogen carbonate was added. Then, 10 parts by weight of dimethoxymethylphenylsilane, 49 parts by weight of dimethyldimethoxysilane, 0.6 parts by weight of trimethylmethoxysilane, and 3.6 parts by weight of methyltrimethoxysilane were added, and the mixture was stirred for 1 hour. Then, 1.9 parts by weight of a 10 wt% potassium hydroxide aqueous solution was added, the temperature was raised to 85 ° C., and the reaction was carried out with stirring for 10 hours while reducing the pressure with an aspirator. After completion of the reaction, the pressure was returned to normal pressure, the mixture was cooled to 40 ° C., 0.2 part by weight of acetic acid was added, and the mixture was allowed to stand in a separating funnel for 12 hours or more. The lower layer after the two-layer separation was taken out and purified by an evaporator to obtain a silicone oligomer.

(2) Preparation of Silicone Particle Material (Including Organic Polymer) In 30 parts by weight of the obtained silicone oligomer, tert-butyl-2-ethylperoxyhexanoate (polymerization initiator, "Perbutyl O" manufactured by Nichiyu Co., Ltd.) 0 A solution A in which 5.5 parts by weight was dissolved was prepared. In addition, in 150 parts by weight of ion-exchanged water, 0.8 parts by weight of a 40% by weight aqueous solution of triethanolamine lauryl sulfate (embroidery) and polyvinyl alcohol (degree of polymerization: about 2000, degree of saponification: 86.5-89 mol%, Japan An aqueous solution B was prepared by mixing with 80 parts by weight of a 5% by weight aqueous solution of "Gosenol GH-20" manufactured by Synthetic Chemical Co., Ltd. The solution A was placed in a separable flask placed in a warm bath, and then the aqueous solution B was added. Then, emulsification was carried out by using a Shirasu Porous Glass (SPG) membrane (pore average diameter of about 1 μm). Then, the temperature was raised to 85 ° C., and polymerization was carried out for 9 hours. The entire amount of the polymerized particles was washed with water by centrifugation and freeze-dried. After drying, the particles are pulverized with a ball mill until the agglomerates of the particles have the desired ratio (average secondary particle size / average primary particle size) to obtain silicone particles (base particle B) having a particle size of 3.0 μm. Obtained.

High-purity Ni on the outer surface of the base particles in the same manner as in Example 1 except that the base particles A were changed to the base particles B and the thickness of the conductive layer was changed from 51 nm to 52 nm. Conductive particles in which the conductive parts of the above were arranged were obtained.

(Example 12)
Base particle C having a particle size of 10.0 μm, which differs only from the base particle A in particle size, was prepared.

High-purity Ni on the outer surface of the base particles in the same manner as in Example 1 except that the base particles A were changed to the base particles C and the thickness of the conductive layer was changed from 51 nm to 90 nm. Conductive particles in which the conductive parts of the above were arranged were obtained.

(Example 13)
A base particle D having a particle size of 1.5 μm, which differs only from the base particle A in the particle size, was prepared.

High-purity Ni on the outer surface of the base particles in the same manner as in Example 1 except that the base particles A were changed to the base particles D and the thickness of the conductive layer was changed from 51 nm to 32 nm. Conductive particles in which the conductive parts of the above were arranged were obtained.

(Example 14)
A 1000 mL separable flask equipped with a four-neck separable cover, a stirring blade, a three-way cock, a cooling tube and a temperature probe was prepared. Ion-exchanged water was placed in the separable flask, and 100 mmol of methyl methacrylate, 1 mmol of N, N, N-trimethyl-N-2-methacryloyloxyethylammonium chloride, and 2,2'-azobis (2-amidinopropane) were added. ) The monomer composition containing 1 mmol of dihydrochloride was weighed so that the solid content was 5% by weight. Then, the mixture was stirred at 200 rpm and polymerized at 70 ° C. for 24 hours under a nitrogen atmosphere. After completion of the reaction, the reaction was freeze-dried to obtain insulating particles having an ammonium group on the surface, having an average particle size of 220 nm and a CV value of 10%.

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

10 g of the conductive particles obtained in Example 1 was dispersed in 500 mL of ion-exchanged water, 4 g of an aqueous dispersion of insulating particles was added, and the mixture was stirred at room temperature for 6 hours. After filtering with a 10 μm mesh filter, the mixture was further washed with methanol and dried to obtain conductive particles to which insulating particles were attached.

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

(Comparative Example 1)
The suspension (1A) of Example 1 was placed in a solution containing 25 g / L of nickel sulfate, 15 ppm of thallium nitrate and 10 ppm of bismuth nitrate to obtain a particle mixture (21).

Further, a nickel-phosphorus plating solution (22) (pH 5.5) containing 100 g / L of nickel sulfate, 60 g / L of sodium hypophosphite, 15 g / L of sodium citrate, 25 ppm of tarium nitrate, and 10 ppm of bismuth nitrate was prepared. ..

The nickel-phosphorus plating solution (22) was gradually added dropwise to the particle mixture (21) at 50 ° C. in which the particles were dispersed, and electroless nickel-phosphorus plating was performed. Then, the mixture was stirred until the pH became stable, and it was confirmed that the foaming stopped, and a suspension (23) after the electroless nickel-phosphorus plating solution was obtained. Then, the suspension (23) is filtered, washed with water, and dried to obtain conductive particles in which a conductive portion (thickness 59 nm) of Ni-P containing no core substance is arranged on the outer surface of the base particles. It was.

(Comparative Example 2)
Same as in Example 1 except that the base particle A was changed to metallic nickel-phosphorus particles (manufactured by Hitachi Metals Neomaterial Co., Ltd., average particle diameter 20 μm) and the thickness of the conductive layer was changed from 51 nm to 49 nm. To obtain conductive particles.

(Evaluation)
(1) 10% K value of base particle The base particle (excluding metal particles) used for the conductive particle is 10% K by the above-mentioned method using "Fisherscope H-100" manufactured by Fisher. The value was measured.

(2) Saturated Magnetization Amount The saturated magnetization amount was measured using the obtained conductive particles. The amount of magnetization was calculated by measuring the magnetic hysteresis curve of the conductive particles. A vibrating sample magnetometer (“BHV-50” manufactured by RIKEN Electronics Co., Ltd.) was used as an apparatus. Further, the sample was prepared by sealing 15 mg of the dried conductive particles in the sample holder without compression, and the measurement was carried out.

(3) Sedimentation speed (movement characteristics of conductive particles)
0.5 g of conductive particles were placed in a 30 mL vial. Further, the vial was filled with 30 mL of pure water, and the vial was treated with ultrasonic waves for 30 seconds to disperse the conductive particles. A vial in which the conductive particles were dispersed was placed on a magnet having a surface area larger than the bottom surface of the vial, and left until the conductive particles completely settled.

After settling, the magnet and the vial were rotated 180 ° in close contact with each other and turned upside down, and the time until the settling particles reached the bottom surface without being held on the magnet surface was measured.

[Criteria for sedimentation rate]
○○: Particles do not settle even after 10 minutes or more ○: Bottom arrival time of settling particles is 5 minutes or more and less than 10 minutes ×: Bottom arrival time of settled particles is less than 5 minutes

(4) Electrode damage Fabrication of anisotropic conductive film:
30 parts by weight of a phenoxy compound ("PKHC" manufactured by Inchem), which is a thermosetting compound, is placed in a mixed solvent of 35 parts by weight of PGMEA and 35 parts by weight of methyl ethyl ketone, and stirred at room temperature for 24 hours to obtain a 30% by weight dispersion of the phenoxy compound. Got Next, 30 parts by weight of the dispersion liquid, 30 parts by weight of an epoxy compound (“EPICLON HP-4032D” manufactured by DIC) which is a thermosetting compound, and a microcapsule curing agent (Asahi Kasei Co., Ltd.) of imidazole which is a latent thermosetting agent. 30 parts by weight of "Novacure HXA3922" manufactured by Novacure HXA3922 and 1 part by weight of a silane coupling agent ("KBM-403" manufactured by Shinetsu Chemical Industry Co., Ltd.) were blended. After adding the conductive particles to the obtained formulation so that the content in 100% by weight of the conductive film capable of obtaining the conductive particles is 10% by weight, methyl ethyl ketone is further added so that the solid content is 50% by weight. A conductive paste was obtained by stirring at 2000 rpm for 5 minutes using a planetary stirrer. The obtained conductive paste was applied onto the stripped polyethylene terephthalate, and the solvent was dried to obtain an anisotropic conductive film having a thickness of 20 μm.

Fabrication of connection structure:
Electrode pattern with L / S of 20 μm / 20 μm (composite electrode in which a TiO electrode portion with a thickness of 0.35 μm, an AlTi electrode portion with a thickness of 1.0 μm, and an IZO electrode portion with a thickness of 0.1 μm are laminated in this order) Was prepared on the upper surface. Further, a semiconductor chip having a gold electrode pattern (gold electrode thickness 20 μm) having an L / S of 20 μm / 20 μm on the lower surface was prepared.

An anisotropic conductive film was placed on the upper surface of the glass substrate to form an anisotropic conductive film layer. Next, the semiconductor chips were laminated on the upper surface of the anisotropic conductive film 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 film layer becomes 130 ° C., the pressure heating head is placed on the upper surface of the semiconductor chip, and the pressure of 70 MPa per total area of the connecting portion of the bump electrode is applied. The connection structure was obtained.

Using the obtained connection structure, electrode damage was determined according to the following criteria. In addition, the comparison of electrode damage based on the presence or absence of particle crushing is that if the particles are in contact with the electrode without being crushed, there is a high possibility that they are biting into the electrode and there is a possibility that the electrode is damaged. On the contrary, when the particles are crushed, it is unlikely that they are biting into the electrode and it is unlikely that the electrode is damaged.

[Criteria for electrode damage]
◯: Particles are crushed and are in contact with the electrode ×: Particles are not crushed and are in contact with the electrode

(5) Connection resistance Using the connection structure obtained in the evaluation of electrode damage in (4) above, the connection resistance between the electrodes was measured by the 4-terminal method. In addition, the initial connection resistance was determined according to the following criteria. The connection resistance is preferably 10 Ω or less, more preferably 5.0 Ω or less, further preferably 3.0 Ω or less, and particularly preferably 1.5 Ω or less. The connection resistance was judged according to the following criteria.

[Criteria for connection resistance]
○ ○: Connection resistance is 1.0Ω or less ○: Connection resistance is more than 1.0Ω, 5.0Ω or less ×: Connection resistance is more than 5.0Ω

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

1 ... Conductive particles 2 ... Substrate particles 3 ... Conductive parts 11 ... Conductive particles 11a ... Protrusions 12 ... Conductive parts 12a ... Protrusions 13 ... Core material 14 ... Insulating material 21 ... Conductive particles 21a ... Protrusions 22 ... Conductive parts 22a ... Protrusion 22A ... First conductive part 22Aa ... Protrusion 22B ... Second conductive part 22Ba ... Protrusion 31 ... Conductive particles 51 ... Connection structure 52 ... First connection target member 52a ... First electrode 53 ... First 2 Connection target member 53a ... Second electrode 54 ... Connection part 61 ... Conductive material X ... Magnetic field or magnetic force

Claims (15)

Base particles and
It is provided with a conductive portion arranged on the surface of the base particle.
Conductive particles having a saturation magnetization amount of 10 emu / g or more. The conductive particle according to claim 1, wherein the base particle is not a metal particle. The conductive particles according to claim 1, wherein the base particles are resin particles or organic-inorganic hybrid particles. The conductive particle according to any one of claims 1 to 3, wherein the conductive portion contains nickel, cobalt or iron. The conductive particles according to claim 4, wherein the total content of nickel, cobalt and iron in 100% by weight of the conductive portion is 90% by weight or more. The conductive portion contains at least two of nickel, cobalt and iron.
The conductive particles according to claim 4 or 5, wherein the content of one of the nickel content, the cobalt content and the iron content in 100% by weight of the conductive portion is 51% by weight or more. Compression modulus when the base particle is compressed by 10% at 25 ° C. is, 1000 N / mm ² or more 30000 N / mm ² or less, the conductive particles according to any one of claims 1-6. The conductive particle according to any one of claims 1 to 7, wherein the base particle has a particle size of 1 μm or more and 10 μm or less. The conductive particle according to any one of claims 1 to 8, wherein the specific gravity of the base particle is lower than the specific gravity of the conductive portion. The conductive particle according to any one of claims 1 to 9, which is used for a conductive connection to which a magnetic field or a magnetic force is applied. The conductive particle according to any one of claims 1 to 10, which has a protrusion on the outer surface of the conductive portion. The conductive particle according to any one of claims 1 to 11, further comprising an insulating substance arranged on the outer surface of the conductive portion. A conductive material containing the conductive particles according to any one of claims 1 to 12 and a binder resin. A first connection target member having a first electrode on its surface,
A second connection target member having a second electrode on the surface,
The first connection target member and the connection portion connecting the second connection target member are provided.
The material of the connecting portion is the conductive particles according to any one of claims 1 to 12, or is a conductive material containing the conductive particles and a binder resin.
A connection structure in which the first electrode and the second electrode are electrically connected by the conductive particles. The conductive particles according to any one of claims 1 to 12 are arranged on the surface of the first connection target member having the first electrode on the surface, or the conductive particles and the binder resin are placed on the surface. The first placement step of arranging the conductive material to be included, and
A second arrangement step of arranging a second connection target member having a second electrode on the surface of the conductive particles or the conductive material opposite to the first connection target member side.
A step of applying a magnetic field or a magnetic force is provided before or after the second placement step.
A method for manufacturing a connection structure, which obtains a connection structure in which the first electrode and the second electrode are electrically connected by the conductive particles.

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