JP6123283B2 - Connection structure of conductive particles, anisotropic conductive material and circuit member - Google Patents

Description

  The present invention relates to a connection structure of conductive particles, an anisotropic conductive material, and a circuit member.

  The method of mounting the liquid crystal driving IC on the glass panel for liquid crystal display can be roughly classified into two types, COG (Chip on Glass) mounting and COF (Chip on Flex) mounting. In COG mounting, an IC for liquid crystal is directly bonded onto a glass panel using an anisotropic conductive material containing conductive particles. On the other hand, in COF mounting, a liquid crystal driving IC is bonded to a flexible tape having metal wiring, and these are bonded to a glass panel using an anisotropic conductive material containing conductive particles. Note that the anisotropic conductive material here means a material that has conductivity in the pressurizing direction and maintains insulation in the non-pressurizing direction.

  When bonding using an anisotropic conductive material, it is necessary that the conductive particles be sufficiently deformed by the pressure at the time of bonding and not be destroyed by the pressure.

  Therefore, when the conductive particles are composed of polymer particles and a metal layer covering the polymer particles, the polymer particles have a low compressive elastic modulus and excellent breaking strength so that the conductive particles are easily deformed. Is required.

  Patent Document 1 discloses that resin particles mainly composed of an acrylic resin composed of a monomer polymer containing a urethane compound and an acrylic monomer are largely deformed with a small load. Patent Document 2 reports the use of resin particles obtained by suspension polymerization of raw material monomers containing alkylene diol diacrylate in order to reduce the elastic modulus of the resin particles.

  However, in the suspension polymerization, the resin particles obtained are polydispersed and thus have a wide particle size distribution, and in order to be used for conductive particles, it is necessary to classify the resin particles before use, resulting in poor productivity. On the other hand, when seed polymerization is used, it is known that monodisperse resin particles are easily obtained. For example, Patent Documents 3 to 5 also disclose low-elasticity resin particles synthesized using seed polymerization.

  Patent Document 6 discloses the production of crosslinked particles that seed-polymerize polyfunctional monomers such as butanediol diacrylate and hexanediol diacrylate.

International Publication No. 03/104285 Japanese Patent No. 4642286 JP 2005-327509 A Japanese Patent No. 3739232 JP 2010-159328 A Japanese Patent No. 4218848

  However, the conventional conductive particles composed of polymer particles and a metal layer covering the polymer particles are required to be further improved in terms of conduction reliability.

  Then, an object of this invention is to provide the connection structure of the electroconductive particle excellent in conduction | electrical_connection reliability, the anisotropic conductive material containing this electroconductive particle, and a circuit member.

The present invention is a conductive particle having a crosslinked polymer particle and a metal coating formed on the surface of the crosslinked polymer particle, wherein the crosslinked polymer particle is represented by the following formula (1). After swelling in an emulsion containing a monomer containing an alkanediol diacrylate compound, the particles formed by seed polymerization of the monomer are washed with a solvent containing a solvent having a solubility parameter of 15 to 30 MPa ^1/2. The ratio of carbon-carbon double bonds remaining in the crosslinked polymer particles is 7 to 25 mol%, and the crosslinked polymer particles are allowed to stand at 100 ° C. for 12 hours in water for 40% compression deformation modulus. A conductive particle having a change rate of 40% or less is provided.

式中、Ｌ^１は炭素数４〜１２のアルキレン基を示す。

In the formula, L ¹ represents an alkylene group having 4 to 12 carbon atoms.

  By adjusting the average particle diameter of the crosslinked polymer particles to 2.5 to 5.0 μm, it can be used for narrow pitch electrode applications. By setting the Cv value of the particle diameter of the crosslinked polymer particles to 10% or less, the conduction reliability can be further improved.

  When the weight average molecular weight of the seed particles is 3000 to 50000, the monomer is easily absorbed when the seed particles swell.

  When the fracture strength of the crosslinked polymer particles is 15 mN or more, a good indentation is likely to appear on the electrode when mounted using an anisotropic conductive material containing conductive particles.

  When the particle diameter of the crosslinked polymer particles is 3 to 10 times the particle diameter of the seed particles, the characteristics of the alkanediol diacrylate compound are easily developed, and the compression characteristics of the crosslinked polymer particles are further improved.

  From the viewpoint of further improving the conduction reliability, the compression recovery rate at room temperature of the crosslinked polymer particles is preferably 50% or more.

  The present invention further provides an anisotropic conductive material containing the conductive particles and a binder resin.

  According to the present invention, a first circuit member having a first circuit electrode formed on the main surface of the first circuit board, a second circuit electrode formed on the main surface of the second circuit board, A second circuit member disposed so that the two circuit electrodes face the first circuit electrode, and a connection portion interposed between the first circuit member and the second circuit member, and connected. A part provides the connection structure of a circuit member containing the electroconductive particle of the said invention.

  ADVANTAGE OF THE INVENTION According to this invention, the connection structure of the electroconductive particle excellent in conduction | electrical_connection reliability, the anisotropic conductive material containing this electroconductive particle, and a circuit member can be provided.

It is a schematic cross section which shows the electroconductive particle which concerns on this embodiment. It is a schematic cross section which shows the anisotropic conductive material which concerns on this embodiment. It is a schematic cross section which shows the preparation methods of the connection structure of the circuit member which concerns on this embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as the case may be. However, the present invention is not limited to the following embodiments. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant description is omitted.

<Conductive particles>
The electroconductive particle of this embodiment has a crosslinked polymer particle provided with a specific structure, and a metal film formed on the surface of the crosslinked polymer particle.

(Crosslinked polymer particles)
The crosslinked polymer particles according to this embodiment swell the seed particles in an emulsion containing a monomer containing a specific alkanediol diacrylate compound, and then seed-polymerize the monomer, so that the solubility parameter Particles obtained by washing with a solvent containing a solvent of 15 to 30 MPa ^1/2 . The cross-linked polymer particles have a ratio of carbon-carbon double bonds remaining in the cross-linked polymer particles of 7 to 25 mol%, and 40% when the cross-linked polymer particles are left at 100 ° C. in water for 12 hours. The rate of change of the compressive deformation elastic modulus is 40% or less.

(Seed particles)
The seed particles are not particularly limited, and examples thereof include vinyl resin particles such as acrylic particles and styrene particles.

  Acrylic particles are particles obtained by polymerization of (meth) acrylic monomers. Examples of (meth) acrylic monomers include acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, dodecyl acrylate, stearyl acrylate, 2-acrylic acid 2- Ethylhexyl, tetrahydrofurfuryl acrylate, diethylaminoethyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-octyl methacrylate, methacryl Examples include dodecyl acid, 2-ethylhexyl methacrylate, stearyl methacrylate, and diethylaminoethyl methacrylate. These monomers may be used alone or in combination of two or more.

  The acrylic particles may be particles obtained by copolymerization of a (meth) acrylic monomer and another monomer. Examples of other monomers include glycol esters of (meth) acrylic acid such as ethylene glycol mono (meth) acrylate and polyethylene glycol mono (meth) acrylate; alkyl vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; vinyl acetate , Vinyl esters such as vinyl butyrate; N-alkyl substituted (meth) acrylamides such as N-methylacrylamide, N-ethylacrylamide, N-methylmethacrylamide and N-ethylmethacrylamide; nitriles such as acrylonitrile and methacrylonitrile Polyfunctional monomers such as divinylbenzene, ethylene glycol di (meth) acrylate, trimethylolpropane triacrylate; styrene, p-methylstyrene, p-chlorostyrene, chloromethyls Ren, styrenic monomers such as α- methyl styrene. These other monomers may be used alone or in combination of two or more.

  Styrenic particles are particles obtained by polymerization of styrene monomers such as styrene, p-methylstyrene, p-chlorostyrene, chloromethylstyrene, and α-methylstyrene. These styrene monomers may be used alone or in combination of two or more.

  The styrenic particles may be particles obtained by copolymerization of a styrenic monomer and another monomer. Examples of other monomers include glycol esters of (meth) acrylic acid such as ethylene glycol mono (meth) acrylate and polyethylene glycol mono (meth) acrylate; alkyl vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; vinyl acetate , Vinyl esters such as vinyl butyrate, N-alkyl substituted (meth) acrylamides such as N-methylacrylamide, N-ethylacrylamide, N-methylmethacrylamide and N-ethylmethacrylamide; nitriles such as acrylonitrile and methacrylonitrile Polyfunctional monomers such as divinylbenzene, ethylene glycol di (meth) acrylate, trimethylolpropane triacrylate; acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate , Isobutyl acrylate, tert-butyl acrylate, dodecyl acrylate, stearyl acrylate, 2-ethylhexyl acrylate, tetrahydrofurfuryl acrylate, diethylaminoethyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate , (Meth) acrylic monomers such as n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, diethylaminoethyl methacrylate, etc. Is mentioned. These other monomers may be used alone or in combination of two or more.

  The seed particles can be synthesized by a known method such as an emulsion polymerization method, a soap-free emulsion polymerization method, or a dispersion polymerization method.

  When the weight average molecular weight (Mw) of the seed particles increases, the absorption capacity of the monomer decreases, or the mechanical strength tends to decrease due to phase separation with the monomer to be absorbed, and when the seed particles decrease, the particle diameter becomes difficult to be uniform. Therefore, the Mw of the seed particles is preferably 50000 or less, and more preferably 30000 or less. Moreover, 3000 or more are preferable and, as for Mw of a seed particle, 5000 or more are more preferable. In addition, Mw prescribed | regulated by this specification is the value measured using the analytical curve by a standard polystyrene by the gel permeation chromatography method (GPC).

  The average particle size of the seed particles can be adjusted according to the design particle size of the obtained crosslinked polymer particles. When the average particle size of the seed particles increases, it takes time to absorb the monomer, and when the average particle size decreases, the particle size becomes non-uniform and the sphericity tends to decrease. The average particle size of the seed particles is preferably 0.1 to 2 μm, more preferably 0.5 to 2.0 μm, and still more preferably 0.5 to 1.5 μm.

  The Cv value, which is the coefficient of variation of the particle size (diameter) of the seed particles, is preferably 10% or less, more preferably 7% or less, since the uniformity of the resulting crosslinked polymer particles tends to decrease as the seed particle size (diameter) increases. 5% or less is more preferable.

  The average particle size of the seed particles and the Cv value of the particle size can be calculated by observing 100 seed particles of interest with a scanning electron microscope (SEM) and measuring the particle size. It is also possible to calculate from the particle size measured using a particle size measuring device such as a meter (manufactured by Nikkiso).

(Method for producing crosslinked polymer particles)
The crosslinked polymer particles are obtained by swelling the seed particles in an emulsion containing a monomer containing an alkanediol diacrylate compound represented by the following formula (1), and then seed-polymerizing the monomers. It is obtained by washing with a solvent containing a solvent having a solubility parameter of 15 to 30 MPa ^1/2 .

In the formula, L ¹ represents an alkylene group having 4 to 12 carbon atoms. The alkylene group may be linear, branched or cyclic.

  The seed polymerization method can be performed with reference to a known method. A general method of the seed polymerization method will be described below, but is not limited to this method.

  First, seed particles are added to an emulsion containing a monomer and an aqueous medium. The seed particles may be added directly to the emulsion or may be added in a form in which the seed particles are dispersed in an aqueous dispersion.

  The emulsion can be prepared by a known method. For example, an emulsion can be obtained by adding a monomer to an aqueous medium and dispersing the monomer in an aqueous medium using a fine emulsifier such as a homogenizer, an ultrasonic processor, or a nanomizer. The emulsion may contain a polymerization initiator as necessary. The polymerization initiator may be mixed in advance with the monomer and then dispersed in an aqueous medium, or a mixture of a polymerization initiator and a monomer separately dispersed in an aqueous medium may be mixed. When the particle size of the monomer droplets in the obtained emulsion is smaller than the particle size of the seed particles, the monomer is efficiently absorbed by the seed particles.

  After the seed particles are added to the emulsion, the seed particles are swollen to absorb the monomer. This absorption can be normally performed by stirring the emulsion after adding the seed particles at room temperature for 1 to 24 hours. Moreover, absorption of a monomer can be accelerated | stimulated by heating an emulsion to about 30-50 degreeC.

  The seed particles swell upon absorption of the monomer. When the mixing ratio of the monomer to the seed particle is reduced, the increase in the particle size of the crosslinked polymer particle produced by the seed polymerization of the monomer is reduced, and the productivity of the crosslinked polymer particle tends to be lowered. On the other hand, when the mixing ratio of the monomer is increased, the monomer may not be absorbed by the seed particles, and the monomer may be uniquely suspension-polymerized in the aqueous medium, and particles other than the target particle size may be generated. The completion of monomer absorption can be determined by observing seed particles using an optical microscope and confirming the increase in particle size.

  The emulsion according to the present embodiment contains an alkanediol diacrylate compound represented by the above formula (1) as a monomer. From the viewpoint of easily achieving both low elasticity and compression recovery of the crosslinked polymer particles, the content of the alkanediol diacrylate compound represented by the formula (1) may be 90 mol% or more based on the total amount of the monomers. Preferably, it is 92.5 mol% or more, more preferably 95 mol% or more.

  Examples of the alkanediol diacrylate compound represented by the above formula (1) include 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, and 1,6-hexanediol. Diacrylate, 1,7-heptanediol diacrylate, 1,8-octanediol diacrylate, 3-methyl-1,5-pentanediol diacrylate, 1,9-nonanediol diacrylate, 1,10-decanediol diacrylate Examples thereof include acrylate and neopentyl glycol diacrylate.

  As a monomer, other polyfunctional monomers and / or monofunctional monomers can be used in combination with the alkanediol diacrylate compound represented by the above formula (1).

  Examples of multifunctional monomers include divinyl compounds such as divinylbenzene, divinylbiphenyl, divinylnaphthalene; (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, and (poly) tetramethylene glycol. (Poly) alkylene glycol-based di (meth) acrylates such as di (meth) acrylate; trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolpropane tetra (meth) acrylate, pentaerythritol tri ( (Meth) trifunctional or higher (meth) such as (meth) acrylate, 1,1,1-trishydroxymethylethane tri (meth) acrylate, 1,1,1-trishydroxymethylpropane triacrylate Acrylate; ethoxylated bisphenol A di (meth) acrylate, propoxylated ethoxylated bisphenol A di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, 1,1,1-trishydroxymethylethanedi (meta ) Acrylates, di (meth) acrylates such as ethoxylated cyclohexanedimethanol di (meth) acrylate; diallyl phthalate and isomers thereof; triallyl isocyanurate and derivatives thereof. Among these monomers, NK ester (A-TMPT-6P0, A-TMPT-3E0, A-TMM-3LMN, A-GLY series, A-9300, AD-TMP, AD-manufactured by Shin-Nakamura Chemical Co., Ltd. TMP-4CL, ATM-4E, A-DPH) and the like are commercially available. These polyfunctional monomers may be used alone or in combination of two or more.

  Examples of the monofunctional monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene, 2,4- Dimethyl styrene, pn-butyl styrene, pt-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl Styrene such as styrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene and derivatives thereof; methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, acrylic acid Isobutyl, hexyl acrylate, 2-ethylhexyl acrylate, acrylic acid n-o Chill, dodecyl acrylate, lauryl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, methacryl (Meth) acrylic acid esters such as isobutyl acid, hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, stearyl methacrylate; vinyl acetate, vinyl propionate, vinyl benzoate, Vinyl esters such as vinyl butyrate; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone; vinyl fluoride, vinylidene fluoride, tetrafluoroe Ren, hexafluoropropylene, trifluoroethyl acrylate, fluorine-containing monomers such as acrylic acid tetrafluoropropyl; butadiene include conjugated dienes such as isoprene. These can be used alone or in combination of two or more.

  Examples of the aqueous medium include water or a mixed medium of water and a water-soluble solvent (for example, lower alcohol). The aqueous medium contains a surfactant. As the surfactant, any of anionic, cationic, nonionic and zwitterionic surfactants can be used.

  Examples of the anionic surfactant include fatty acid oils such as sodium oleate and castor oil potassium, alkyl sulfate salts such as sodium lauryl sulfate and ammonium lauryl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, and alkylnaphthalene sulfone. Acid salts, alkane sulfonates, dialkyl sulfosuccinates such as sodium dioctyl sulfosuccinate, alkenyl succinates (dipotassium salts), alkyl phosphate esters, naphthalene sulfonate formalin condensates, polyoxyethylene alkylphenyl ether sulfates Examples thereof include salts, polyoxyethylene alkyl ether sulfates such as sodium polyoxyethylene lauryl ether sulfate, and polyoxyethylene alkyl sulfate salts.

  Examples of the cationic surfactant include alkylamine salts such as laurylamine acetate and stearylamine acetate, and quaternary ammonium salts such as lauryltrimethylammonium chloride.

  Nonionic surfactants include, for example, hydrocarbon nonionic surfactants such as polyethylene glycol alkyl ethers, polyethylene glycol alkyl aryl ethers, polyethylene glycol esters, polyethylene glycol sorbitan esters, polyalkylene glycol alkylamines, or amides. Agents, polyether-modified silicon-based nonionic surfactants such as polyethylene oxide adducts of silicon and polypropylene oxide adducts, and fluorine-based nonionic surfactants such as perfluoroalkyl glycols.

  Examples of zwitterionic surfactants include hydrocarbon surfactants such as lauryl dimethylamine oxide, phosphate ester surfactants, and phosphite ester surfactants.

  One surfactant may be used alone, or two or more surfactants may be used in combination. Among the above surfactants, an anionic surfactant is preferable from the viewpoint of dispersion stability during polymerization of the monomer.

  Examples of the polymerization initiator added as necessary include benzoyl peroxide, lauroyl peroxide, orthochlorobenzoyl peroxide, orthomethoxybenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, tert-butyl peroxide. Organic peroxides such as oxy-2-ethylhexanoate and di-tert-butyl peroxide; 2,2′-azobisisobutyronitrile, 1,1′-azobiscyclohexanecarbonitrile, 2,2 ′ -Azo compounds such as azobis (2,4-dimethylvaleronitrile). The polymerization initiator may be used in the range of 0.1 to 7.0 parts by mass with respect to 100 parts by mass of the monomer.

  Next, the monomer absorbed in the seed particles is seed-polymerized.

  The polymerization temperature can be appropriately selected according to the types of the monomer and the polymerization initiator. The polymerization temperature is preferably 25 to 110 ° C, more preferably 50 to 100 ° C. The polymerization reaction is preferably carried out at an elevated temperature after the seed particles are sufficiently swollen and the monomer and optionally the polymerization initiator are completely absorbed.

  In the polymerization step, a polymer dispersion stabilizer may be added to the emulsion in order to improve the dispersion stability of the seed particles.

  Examples of the polymer dispersion stabilizer include polyvinyl alcohol, polycarboxylic acid, celluloses (hydroxyethyl cellulose, carboxymethyl cellulose, etc.), polyvinyl pyrrolidone, and an inorganic water-soluble polymer compound such as sodium tripolyphosphate. Can do. Of these, polyvinyl alcohol or polyvinyl pyrrolidone is preferred. The addition amount of the polymer dispersion stabilizer is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the monomer.

  In order to suppress the generation of particles in which the monomer is emulsion-polymerized alone in water, water-soluble polymerization inhibitors such as nitrites, sulfites, hydroquinones, ascorbic acids, water-soluble vitamin Bs, citric acid, and polyphenols are used. It may be used.

After the seed polymerization is completed, the aqueous medium is removed from the polymerization solution by centrifugation as necessary, and the particles formed by the seed polymerization are washed with a solvent containing a solvent having a solubility parameter of 15 to 30 MPa ^1/2 . Thereafter, the crosslinked polymer particles are isolated by drying. By washing the particles with a solvent containing a specific solvent, the polymerization initiator remaining in the particles dissolves, and the storage stability of the crosslinked polymer particles and the conduction reliability of the conductive particles are improved. be able to. As said solvent, organic solvents, such as methanol, ethyl acetate, toluene, methyl ethyl ketone, can be used, for example. These solvent can be used individually by 1 type or in mixture of 2 or more types.

  The average particle diameter of the crosslinked polymer particles is preferably 10 μm or less, more preferably 8 μm or less, still more preferably 6 μm or less, and particularly preferably 5.0 μm or less. The average particle size of the crosslinked polymer particles is preferably 1 μm or more, more preferably 1.75 μm or more, still more preferably 2.5 μm or more, and particularly preferably 3.0 μm or more. If the average particle size is small, the crosslinked polymer particles may easily aggregate.

  The Cv value of the particle diameter (diameter) of the crosslinked polymer particles is the performance of the crosslinked polymer particles in various applications (for example, connection reliability when the crosslinked polymer particles are used as conductive particles constituting an anisotropic conductive agent, From the viewpoint of further improving the quantitativeness when the crosslinked polymer particles are used in a biopsy element, it is preferably 10% or less. From the same viewpoint, the Cv value of the particle diameter of the crosslinked polymer particles is more preferably 8% or less, still more preferably 5% or less, and still more preferably 4% or less.

The average particle diameter and the Cv value of the particle diameter of the crosslinked polymer particles can be determined by the following measurement method.
1) Disperse particles in water using an ultrasonic dispersion device to prepare a dispersion containing 1% by mass of particles.
2) Using a particle size distribution meter (Sysmex Flow, manufactured by Sysmex), an image of about 100,000 particles in the dispersion was observed with a scanning electron microscope (SEM), and the average particle size and the Cv value of the particle size were measured. Is calculated.

  From the viewpoint of sufficiently allowing the interaction between the seed particles and the polymer synthesized from the monomer containing the alkanediol diacrylate compound represented by the above formula (1), the final particle size of the seed particles is obtained. It is preferable to adjust the particle diameter of the crosslinked polymer particles to be 3 to 10 times, more preferably 3 to 7 times, and still more preferably 4 to 6 times. By setting the particle size ratio within the above range, the compression characteristics of the crosslinked polymer particles can be further improved.

From the viewpoint of reducing the compression elastic modulus of the crosslinked polymer particles, the ratio of carbon-carbon double bonds remaining in the crosslinked polymer particles (double bond remaining ratio) is the amount of carbon present in the total amount of monomers that swell the seed particles. It is 7-25 mol% on the basis of a carbon double bond, it is preferable that it is 7-23 mol%, and it is more preferable that it is 7-20 mol%. The residual rate of double bonds was determined by measuring the infrared absorption spectrum of the powder of crosslinked polymer particles isolated from the prepared dispersion of crosslinked polymer particles, and then measuring the carbonyl (-C = O) appearing near 1730 cm ^-1 . It can be calculated from the peak intensity of the carbon-carbon double bond appearing in the vicinity of 815 cm ^{−1 based on} the peak intensity and the same peak intensity of the monomer.

  The compression recovery rate representing the compression characteristics of the crosslinked polymer particles can be measured by the following method.

  The compression recovery rate was measured by using a micro compression tester (manufactured by Fisher) at a room temperature (25 ° C.) load rate of 0.33 mN / sec. It is obtained by measuring the relationship between the load value and the compression displacement when the load is reduced at a speed of 0.33 mN / sec after compression from the center to 5 mN. The ratio (L1 / L2) of the displacement (L1) from the point of reversing the load to the final unloading value and the displacement (L2) from the point of reversal to the initial unloading value is expressed in% as a compression recovery rate. It is. In this embodiment, an average value measured five times is used. In this embodiment, “room temperature” is 25 ° C.

  The compression recovery rate of the crosslinked polymer particles at room temperature is preferably 50% or more, more preferably 55% or more.

  The compression modulus and breaking strength when the crosslinked polymer particles are compressed can be measured by the following method.

Using a micro compression tester (Fisher), the load and compressive displacement when the crosslinked polymer particles are compressed to 50 mN with a square column smooth end face (50 μm × 50 μm) at a load rate of 1 mN / sec at room temperature. Measure. From the measured values obtained, the compression modulus (40% K value) when the crosslinked polymer particles are 40% compressively deformed can be determined by the following formula. Further, the load at the point at which the displacement during the measurement changes most greatly is defined as the breaking strength (mN).
40% K value (kgf / mm ² = 9.81 × 10 ⁶ N / m ² ) = (3/2 ^1/2 ) · F · S ⁻³ / ² · R ^−1/2
F: Load (mN) when the crosslinked polymer particles are 40% compressively deformed
S: Compression displacement (mm) when the crosslinked polymer particles are 40% compressively deformed
R: radius of cross-linked polymer particles (mm)

The compression modulus when the crosslinked polymer particles are 40% compressively deformed is preferably 150 to 400 kgf / mm ² (1.47 to 3.92 × 10 ⁹ N / m ² ), and 200 to 400 kgf / mm ^2. (1.96 to 3.92 × 10 ⁹ N / m ² ) is more preferable, and 250 to 380 kgf / mm ² (2.45 to 3.73 × 10 ⁹ N / m ² ) is even more preferable. preferable.

  If the 40% K value is too small, the flexibility of the crosslinked polymer particles becomes too high, and an anisotropic conductive material containing conductive particles having a conductive layer formed on the surface of the crosslinked polymer particles and a binder resin is used. When connecting the electrodes, it becomes difficult to sufficiently eliminate the binder resin between the conductive particles and the electrodes. If the 40% K value is too large, the flexibility of the crosslinked polymer particles may be too low, and the electrode may be damaged by the conductive particles.

  From the viewpoint of clarifying indentations based on conductive particles during mounting using an anisotropic conductive material, the breaking strength of the crosslinked polymer particles is preferably 15 mN or more, more preferably 16 mN or more, and 17 mN. More preferably, it is the above.

  When the cross-linked polymer particles are left in water at 100 ° C. for 12 hours, the change rate of 40% compression deformation modulus (40% K value change rate) is 40% or less. The 40% K value change rate of the crosslinked polymer particles can be measured by the following method.

0.5 g of the crosslinked polymer particles whose 40% K value was measured by the above-mentioned method were dispersed in 25 g of ion-exchanged water, left in a pressure vessel at 100 ° C. for 12 hours (heating test), then taken out, and the 40% K value was determined. taking measurement. From the obtained measured value, the 40% K value change rate can be obtained by the following formula.
40% K value change rate (%) = [(40% K value before heating test) − (40% K value after heating test)] / (40% K value before heating test) × 100

  The 40% K value change rate of the crosslinked polymer particles is preferably 35% or less, more preferably 30% or less, and further preferably 20% or less from the viewpoint of further improving the conduction reliability. Preferably, it is particularly preferably 10% or less.

<Conductive particles>
The electroconductive particle of this embodiment has the said crosslinked polymer particle and the metal film formed on the surface of this crosslinked polymer particle. FIG. 1 is a schematic cross-sectional view showing conductive particles according to this embodiment. As shown in FIG. 1, the conductive particle 10 includes a crosslinked polymer particle 1 and a metal coating (metal layer) 2 that covers the surface of the crosslinked polymer particle 1.

  Although the metal which comprises the metal layer 2 is not specifically limited, For example, gold, palladium, silver, copper, platinum, zinc, iron, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, Examples include germanium, cadmium, tin-lead alloy, tin-copper alloy, tin-silver alloy, and tin-lead-silver alloy. Especially, it is preferable that the metal layer 2 contains nickel, copper, palladium, gold | metal | money, or a tin-silver alloy.

  The method for forming the metal layer 2 on the surface of the crosslinked polymer particle 1 is not particularly limited. Examples of the method for forming the metal layer 2 include an electroless plating method, an electroplating method, a physical vapor deposition method, and a method of applying a paste containing metal powder to the surface of the crosslinked polymer particle 1. As physical vapor deposition, vacuum vapor deposition, ion plating, or ion sputtering can be used. As a method for forming the metal layer 2, an electroless plating method is preferable.

  The metal layer 2 may be a single layer or a plurality of metal layers in which two or more layers are laminated. From the viewpoint of reducing the connection resistance between the electrodes, the surface of the conductive particles 10 (the outermost layer of the metal layer 2) is preferably a gold layer, a palladium layer, or a tin-silver alloy layer.

  The thickness of the metal layer 2 is preferably 0.02 to 1 μm, and more preferably 0.02 to 0.5 μm. If the thickness of the metal layer 2 is 0.02 μm or more, good conductivity is easily developed, and if it is 1 μm or less, the conductive particles are easily deformed during connection. The thickness of the metal layer 2 can be calculated | required by observing the cross section of electroconductive particle, for example using a transmission electron microscope (TEM).

  The average particle size of the conductive particles 10 is preferably 1.02 to 11 μm, more preferably 1.5 to 10 μm, still more preferably 2 to 7 μm, and even more preferably 2.5 to 5 μm.

  The Cv value of the particle diameter of the conductive particles 10 is preferably 10% or less, more preferably 7% or less, and still more preferably 5% or less. When the Cv value of the conductive particles 10 is 10% or less, the electrical connection reliability can be further increased.

  The average particle diameter and the Cv value of the particle diameter of the conductive particles 10 can be measured by the same method as that for the crosslinked polymer particles 1.

<Anisotropic conductive material>
The anisotropic conductive material of the present embodiment includes the conductive particles and a binder resin. FIG. 2 is a schematic cross-sectional view showing the anisotropic conductive material according to the present embodiment. The anisotropic conductive material 40 includes an insulating binder resin 20 and conductive particles 10 dispersed in the binder resin 20.

  As the binder resin 20, a thermosetting resin composition containing a thermosetting resin, a curing agent, a film-forming polymer, or the like can be used.

  Although it does not specifically limit as a thermosetting resin, It is preferable to use an epoxy resin from a heat resistant viewpoint. As the epoxy resin, various epoxy compounds having two or more glycidyl groups in the molecule can be used. For example, bisphenol type epoxy resin, novolac type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, alicyclic ring Formula type epoxy resins, glycidyl amine compounds, glycidyl ether compounds, and glycidyl ester compounds may be mentioned.

When a high-purity product in which impurity ions (Na ⁺ , Cl ^−, etc.), hydrolyzable chlorine, etc. are reduced to 300 ppm or less is used as the epoxy resin, it becomes easy to prevent electromigration.

  Although it does not specifically limit as a hardening | curing agent, A latent hardening | curing agent can be used. Examples of the latent curing agent include imidazole compounds, hydrazide compounds, boron trifluoride-amine complexes, sulfonium salts, amine imides, polyamine salts, and dicyandiamide.

  The film-forming polymer is not particularly limited as long as the anisotropic conductive material can be formed into a film shape. Examples of the film-forming polymer include thermoplastic resins such as phenoxy resin, polyester resin, and polyamide resin.

  The binder resin 20 can be mixed with butadiene rubber, acrylic rubber, styrene-butadiene rubber, silicone rubber, or the like in order to reduce stress after adhesion or to improve adhesion.

  The binder resin 20 can also contain an inorganic filler. As the inorganic filler, for example, a filler made of silica, magnesia, bentonite, smectite, alumina, or boron nitride can be used.

  The binder resin 20 may be a photocurable resin composition containing a photopolymerization initiator such as a radical polymerizable resin and an organic peroxide instead of the thermosetting resin and the curing agent.

  The anisotropic conductive material 40 can be manufactured as follows, for example. First, a binder resin 20 is prepared by dissolving or dispersing a thermosetting resin composition containing an epoxy resin, an acrylic rubber, a latent curing agent, and a film-forming polymer in an organic solvent as necessary. Subsequently, the liquid anisotropic conductive material 40 is produced by dispersing the conductive particles 10 in the binder resin 20. The organic solvent is preferably one that can dissolve the resin component and has a boiling point of 50 to 150 ° C. at normal pressure.

  The liquid anisotropic conductive material 40 can be used as it is for connecting circuit members, but it can also be formed into a film and used. The film-like anisotropic conductive material 40 is peeled from the release film after the liquid anisotropic conductive material 40 is applied onto the release film, the organic solvent is removed below the activation temperature of the curing agent. Can be produced. As the releasable film, a resin film such as a fluororesin film, a polyethylene terephthalate film, and a polyolefin film is preferably used. When the anisotropic conductive material 40 is used in the form of a film, it is convenient from the viewpoint of handleability.

  The thickness of the film-like anisotropic conductive material 40 is relatively determined in consideration of the particle size of the conductive particles 10 and the characteristics of the anisotropic conductive material 40, and is preferably 1 to 100 μm. It is more preferable that it is 3-50 micrometers. If the thickness of the anisotropic conductive material 40 is less than 1 μm, it is difficult to obtain sufficient adhesion, and if it exceeds 100 μm, a large amount of the conductive particles 10 is required to obtain conductivity, which is not realistic.

<Connection structure>
The circuit member connection structure according to the present embodiment includes a first circuit member in which a first circuit electrode is formed on the main surface of the first circuit board, and a first circuit member on the main surface of the second circuit board. A second circuit member on which two circuit electrodes are formed, and a connection portion interposed between the first circuit member and the second circuit member. The second circuit member is disposed so that the second circuit electrode faces the first circuit electrode, and the connection portion includes the conductive particles according to the present embodiment.

  FIG. 3 is a schematic cross-sectional view showing a method for producing a circuit member connection structure using the anisotropic conductive material according to the present embodiment.

  First, as shown in FIG. 3A, a first circuit board 4 on which a first circuit electrode 5 is formed and a second circuit board 6 on which a second circuit electrode 7 is formed are prepared. Then, the anisotropic conductive material 40 is disposed therebetween. At this time, the position is adjusted so that the first circuit electrode 5 and the second circuit electrode 7 face each other. After that, the first circuit board 4 and the second circuit board 6 are laminated while being pressurized and heated in the direction in which the first circuit electrode 5 and the second circuit electrode 7 face each other, as shown in FIG. A connection structure 42 shown in b) is obtained. The connection structure 42 is electrically connected by a cured product of the anisotropic conductive material 40.

  Examples of the first circuit board 4 and the second circuit board 6 include a glass substrate, a tape substrate such as polyimide, a bare chip such as a driver IC, and a rigid package substrate.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the following examples.

[Synthesis of seed particles]
(Synthesis Example 1)
A 500 mL three-necked flask is charged with 70 g of methyl methacrylate (MMA), 2.1 g of octanethiol (OCT), 2.1 g of potassium peroxodisulfate (KPS) and 400 g of water, and heated in a 70 ° C. water bath. Then, stirring was performed for about 8 hours using a stirrer to form seed particles.

(Synthesis Example 2)
Seed particles were formed in the same manner as in Synthesis Example 1 except that 30 g of styrene (ST), 3 g of octanethiol (OCT), 1.5 g of potassium peroxodisulfate (KPS) and 400 g of water were used.

(Synthesis Example 3)
Seed particles were formed in the same manner as in Synthesis Example 1 except that 40 g of styrene (ST), 4 g of octanethiol (OCT), 1.98 g of potassium peroxodisulfate (KPS) and 400 g of water were used.

(Synthesis Example 4)
Seed particles were formed in the same manner as in Synthesis Example 1 except that 30 g of styrene (ST), 2 g of octanethiol (OCT), 1.5 g of potassium peroxodisulfate (KPS) and 400 g of water were used.

(Synthesis Example 5)
Methyl methacrylate (MMA) 55g, octanethiol (OCT) 1.7g, potassium peroxodisulfate (KPS) 1.70g and water 400g are charged all together and heated with a water bath at 70 ° C, using a stirrer. Stir for about 8 hours to form seed particles.

  The particle size of the seed particles obtained in each synthesis example was measured with a microtrack, and the average particle size and the Cv value of the particle size were calculated. Further, the molecular weight of the obtained seed particles was measured using GPC. The results are shown in Table 1.

Example 1
[Production of crosslinked polymer particles]
After dissolving 2 mol% of di-2-ethylhexyl peroxydicarbonate as a polymerization initiator with respect to 400 g of hexanediol diacrylate (HDDA) as a monomer, 6800 g of ion-exchanged water in which 20.4 g of triethanolamine dodecyl sulfate was dissolved. And the mixture was treated with an ultrasonic homogenizer for 10 minutes to prepare an emulsion.

  To this emulsion, 300 g of the seed particle dispersion of Synthesis Example 1 (solid content: 3.70 g) was added and stirred at room temperature for 12 hours, and then polyvinyl alcohol (Nippon GOHSEI, trade name “GH-17”) was added. 1000 g of an aqueous solution containing mass% was added and polymerization was carried out at 55 ° C. for 8 hours to form particles. The formed particles were separated using centrifugal separation, and the separated particles were washed with water and then washed with methanol and a mixed solvent of ethyl acetate / toluene in this order to produce the desired crosslinked polymer particles.

(Characteristics of crosslinked polymer particles)
The characteristics of the produced crosslinked polymer particles were measured by the following method.

  The particle size of the crosslinked polymer particles was measured with a flow type particle size measuring device, and the average particle size and the Cv value of the particle size were calculated.

The produced crosslinked polymer particles were vacuum-dried, and the infrared absorption spectrum was measured using FT-IR. The peak intensity of the carbon-carbon double bond appearing in the vicinity of 815 cm ^{−1 based on} the peak intensity of the carbonyl appearing in the vicinity of 1730 cm ^{−1 of the} obtained infrared absorption spectrum, and the same peak intensity measured for the monomer before polymerization. By comparison, the ratio of carbon-carbon double bonds remaining in the crosslinked polymer particles (double bond residual ratio) was calculated.

  By measuring the load and compression displacement when the crosslinked polymer particles were compressed using a micro compression tester (Fisher) under the above-mentioned conditions, the compression recovery rate at room temperature, the compression fracture strength, and the 40% K value were calculated. .

  After 0.5 g of the crosslinked polymer particles were dispersed in 25 g of ion-exchanged water, the compression characteristics were evaluated again after standing in a pressure vessel at 100 ° C. for 12 hours (heating test), and a 40% K value change rate was calculated.

[Preparation of conductive particles]
A nickel layer having a thickness of 0.2 μm was formed by electroless plating on the surface of the obtained crosslinked polymer particles, and a gold layer having a thickness of 0.04 μm was formed outside the nickel layer to produce conductive particles. . The compression characteristics of the obtained conductive particles were evaluated in the same manner as the crosslinked polymer particles. The evaluation results are shown in Table 3.

(Example 2)
Conductive particles were produced in the same manner as in Example 1 except that 300 g (solid content 5.33 g) of the seed particle dispersion of Synthesis Example 2 was used instead of the seed particle dispersion of Synthesis Example 1.

(Example 3)
Conductive particles were produced in the same manner as in Example 1, except that 300 g of the seed particle dispersion of Synthesis Example 3 (solid content: 8.18 g) was used instead of the dispersion of seed particles of Synthesis Example 1.

Example 4
Conductive particles were produced in the same manner as in Example 1 except that 300 g (solid content: 1.67 g) of the seed particle dispersion of Synthesis Example 4 was used instead of the seed particle dispersion of Synthesis Example 1.

(Example 5)
Conductive particles were produced in the same manner as in Example 1 except that 300 g (solid content: 0.90 g) of the seed particle dispersion of Synthesis Example 5 was used instead of the seed particle dispersion of Synthesis Example 1.

(Example 6)
Conductive particles were produced in the same manner as in Example 1 except that 1,4-butanediol diacrylate (BDDA) was used instead of HDDA.

(Example 7)
Conductive particles were produced in the same manner as in Example 1 except that 2-methylpentanediol diacrylate (MPDA) was used instead of HDDA.

(Example 8)
Conductive particles were produced in the same manner as in Example 1 except that 1,9-nonanediol diacrylate (NDDA) was used instead of HDDA.

Example 9
Conductive particles were produced in the same manner as in Example 1 except that 1,10-decanediol diacrylate (ODDA) was used instead of HDDA.

(Example 10)
Conductive particles were produced in the same manner as in Example 1 except that “polymerization at 55 ° C. for 8 hours” was changed to “polymerization at 60 ° C. for 8 hours”.

(Example 11)
Conductive particles were produced in the same manner as in Example 1 except that “polymerization at 55 ° C. for 8 hours” was changed to “polymerization at 50 ° C. for 8 hours”.

(Example 12)
Conductive particles were produced in the same manner as in Example 1 except that the washing after the synthesis of the crosslinked polymer particles was carried out only with a water / methanol mixed solvent.

(Example 13)
Conductive particles were produced in the same manner as in Example 1 except that the washing after synthesis of the crosslinked polymer particles was carried out only with methanol.

(Comparative Example 1)
Conductive particles were produced in the same manner as in Example 1 except that the polymerization initiator was changed to benzoyl peroxide and “polymerization at 55 ° C. for 8 hours” was changed to “polymerization at 80 ° C. for 8 hours”.

(Comparative Example 2)
Conductive particles were produced in the same manner as in Example 1 except that the polymerization initiator was changed to t-butyl peroctoate and “polymerization at 55 ° C. for 8 hours” was changed to “polymerization at 70 ° C. for 8 hours”. .

(Comparative Example 3)
Conductive particles were produced in the same manner as in Example 1 except that the washing after the synthesis of the crosslinked polymer particles was carried out only with water.

  The properties of the produced crosslinked polymer particles are summarized in Table 2, and the properties of the produced conductive particles are summarized in Table 3, respectively.

[Production of anisotropic conductive material]
An anisotropic conductive material was produced using the conductive particles.

  5 parts by mass of phenoxy resin (trade name “PKHC” manufactured by Union Carbide), acrylic rubber (40 parts by mass of butyl acrylate, 30 parts by mass of ethyl acrylate, 30 parts by mass of acrylonitrile and 3 parts by mass of glycidyl methacrylate, Mw 850,000 ) 18 parts by mass and 15 parts by mass of epoxy resin (trade name “YL-983U” manufactured by Japan Epoxy Resin Co., Ltd.) are dissolved in 10 parts by mass of ethyl acetate, and a cationic curing agent (trade name, manufactured by Sanshin Chemical Industry Co., Ltd.). "SI-60") 2 parts by mass was added to prepare a thermosetting resin composition. Next, after adding 30 parts by mass of an ethyl acetate dispersion of 10 parts by mass of a silica filler (trade name “Aerosil R805”, manufactured by Nippon Aerosil Co., Ltd.) to the thermosetting resin composition, 20 parts by mass of conductive particles and Ultrasonic dispersion was performed by adding 10 parts by mass of ethyl acetate to prepare a liquid anisotropic conductive material.

  A liquid anisotropic conductive material was applied on a silicone-treated polyethylene terephthalate film (thickness 40 μm, hereinafter referred to as “PET film”) with a roll coater and dried at 80 ° C. for 5 minutes to form a film having a thickness of 23 μm. An anisotropic conductive material was prepared.

[Production of connection structure]
Using the produced film-like anisotropic conductive material, a chip (1.7 mm × 17 mm, thickness: 0.5 mm) with gold bumps (area: 30 μm × 90 μm, space 10 μm, height: 15 μm, number of bumps: 362) ) And a glass substrate with an ITO circuit (Geomatec, thickness: 0.7 mm) were connected as follows to produce a connection structure.

The surface opposite to the surface on which the PET film of the film-like anisotropic conductive material cut into a predetermined size (2 mm × 19 mm) is provided on the surface on which the ITO circuit of the glass substrate with the ITO circuit is formed, The film was attached at 80 ° C. and 0.98 MPa (10 kgf / cm ² ) for 5 seconds. Then, the PET film is peeled off, and the gold bumps of the chip and the glass substrate with the ITO circuit are aligned through an anisotropic conductive material, and heated and pressed under conditions of 170 ° C., 70 MPa for 5 seconds. This connection was made to obtain a mounting sample (connection structure).

[Conduction resistance test]
The conduction resistance test of the produced mounting sample (connection structure) was performed as follows. The results are shown in Table 4. The case where the initial conduction resistance was less than 1 to 3Ω was “A”, the case where it was 3 to 10Ω was “B”, and the case where it exceeded 10Ω was “C”.

  Regarding the conduction resistance between the chip electrode / glass electrode of each mounting sample, an average value was obtained when 14 locations were measured. In addition, the conduction resistance measured the initial value and the value after the reliability test (moisture absorption heat test) left to stand for 500 hours on conditions of temperature 85 degreeC and humidity 85%. It is important that the anisotropic conductive material has a high insulation resistance between the chip electrodes and a low conduction resistance between the chip electrode and the glass electrode. The case where the conduction resistance after the reliability test is less than 5Ω is “A”, the case where it is 5 to 10Ω is “B”, and the case where it exceeds 10Ω is “C”.

[Confirmation of indentation]
Using an Olympus BH3-MJL liquid crystal panel inspection microscope, the state of indentation was observed from the glass substrate side by Nomarski differential interference observation. The results are shown in Table 4. The case where the outline could be clearly confirmed was defined as “good”, and the others were defined as “unclear”.

  It was confirmed that by using the conductive particles having the configuration of the present invention, it is possible to produce a circuit member connection structure having excellent conduction reliability.

  According to the present invention, conductive particles having excellent conduction reliability can be obtained. Moreover, according to this invention, the anisotropic conductive material containing this electroconductive particle and the connection structure of a circuit member can be provided.

  DESCRIPTION OF SYMBOLS 1 ... Crosslinked polymer particle, 2 ... Metal layer, 4 ... 1st circuit board, 5 ... 2nd circuit electrode, 6 ... 2nd circuit board, 7 ... 2nd circuit electrode, 10 ... Conductive particle, 20 ... binder resin, 40 ... anisotropic conductive material, 42 ... connection structure.

Claims (9)

A method for producing conductive particles, comprising: crosslinked polymer particles; and a metal film formed on the surface of the crosslinked polymer particles,
Shea over de particles, after swollen with emulsion containing a monomer containing alkanediol diacrylate compound represented by the following formula (1), and seed polymerization to form particles of the monomer, the particles A step of washing with a solvent containing a solvent having a solubility parameter of 15 to 30 MPa ^1/2 to obtain the crosslinked polymer particles ,
The proportion of carbon-carbon double bonds remaining in the crosslinked polymer particles is 7 to 25 mol%, and the crosslinked polymer particles have a 40% compression deformation elastic modulus when left in water at 100 ° C. for 12 hours. Ri der change rate is 40% or less, and the breaking strength of the crosslinked polymer particles is not less than 15 mN, the production method of the conductive particles.

[Wherein, L ¹ represents an alkylene group having 4 to 12 carbon atoms. ] The compression recovery ratio at room temperature of the crosslinked polymer particles is 50% or more, the method for fabricating a conductive particle of claim 1. A method for producing conductive particles, comprising: crosslinked polymer particles; and a metal film formed on the surface of the crosslinked polymer particles,
After the seed particles are swollen in an emulsion containing a monomer containing an alkanediol diacrylate compound represented by the following formula (1), the monomers are seed-polymerized to form particles, and the particles are treated with a solubility parameter. Washing with a solvent containing a solvent having a viscosity of 15 to 30 MPa ^1/2 to obtain the crosslinked polymer particles,
The proportion of carbon-carbon double bonds remaining in the crosslinked polymer particles is 7 to 25 mol%, and the crosslinked polymer particles have a 40% compression deformation elastic modulus when left in water at 100 ° C. for 12 hours. The method for producing conductive particles, wherein the rate of change is 40% or less, and the compression recovery rate at room temperature of the crosslinked polymer particles is 50% or more.

[Wherein, L ¹ represents an alkylene group having 4 to 12 carbon atoms. ] The manufacturing method of the electroconductive particle of Claim 3 whose breaking strength of the said crosslinked polymer particle is 15 mN or more. The manufacturing method of the electroconductive particle as described in any one of Claims 1-4 whose weight average molecular weights of the said seed particle are 3000-50000. The average particle diameter of the said crosslinked polymer particle is 1-10 micrometers, and the manufacturing method of the electroconductive particle as described in any one of Claims 1-5 whose Cv value of a particle size is 10% or less. The particle size of the crosslinked polymer particles, wherein 3 to 10 times the particle size of the seed particles, method for producing a conductive particle according to any one of claims 1-6. Claims 1-7 any one conductive particles obtained by the method for producing a conductive particle according to the comprises a step of dispersing in a binder resin, a manufacturing method of an anisotropic conductive material. A first circuit member having a first circuit electrode formed on a major surface of a first circuit board, a second circuit member having a second circuit electrode formed on the main surface of the second circuit board The manufacturing method according to claim 8, wherein the first circuit electrode and the second circuit electrode are opposed to each other, and between the first circuit member and the second circuit member. Arranging the anisotropic conductive material obtained by the method;
A circuit member connection structure comprising: pressurizing and heating the first circuit board and the second circuit board in a direction in which the first circuit electrode and the second circuit electrode face each other. Body manufacturing method .

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