JP5821551B2 - Conductive particles, anisotropic conductive materials, and conductive connection structures - Google Patents

Description

  The present invention relates to a conductive particle, an anisotropic conductive material, and a conductive connection structure.

  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). In the COG mounting, a liquid crystal IC 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. Here, the anisotropic conductive material means a material that has conductivity in the pressurizing direction and maintains insulation in the non-pressurizing direction.

  In recent years, in such a technical field, with the increase in definition of liquid crystal display, gold bumps that are circuit electrodes of liquid crystal driving ICs are required to have a narrow pitch and a small area. Under such circumstances, there is a problem that the conductive particles contained in the anisotropic conductive material flow out between adjacent circuit electrodes and cause a short circuit. Further, the dispersibility of the conductive particles in the same material (in the film) is important for improving the insulating properties. Especially in COG where the concentration of the conductive particles needs to be increased, the distance between the conductive particles becomes very short, and a short circuit is likely to occur due to the current flowing between the conductive particles. Dispersibility of the conductive particles in the inside is very necessary.

  In order to meet these requirements, Patent Documents 1 to 12 propose the following (1) a method of coating with an insulating coating and (2) a method of coating insulating particles on the surface of conductive particles. Further, Patent Documents 13 and 14 propose methods for modifying the particle surface.

JP-A-7-105716 Japanese Patent No. 3137578 Japanese Patent No. 4539813 JP 2001-195921 A JP 2006-236759 A JP 2009-218228 A Special table 2003-26813 JP 2010-50086 Patent No. 4547128 Patent No. 4391836 Patent No. 4686120 Japanese Patent No. 4505017 JP 2008-138162 A JP 2001-206954 A

(1) Coating with Insulating Film Patent Document 1 discloses conductive particles in which an insulating layer is formed on the surface of conductive particles by hybridization. Further, Patent Documents 2 to 6 disclose a method in which both the solvent resistance and the insulating property are achieved by coating conductive particles with a styrene-acrylic acid copolymer resin and then crosslinking the resin with an aziridine compound. In the case of (1), since the surface of the conductive particles is entirely covered, there is a problem that the conduction resistance is worse than that of the insulating particles coated with the child particles. On the other hand, when the coverage is adjusted without covering the entire surface of the conductive particles, the conduction characteristics are improved, but the conductive particles are physically compared with the case where the surface of the conductive particles is coated with the child particles. Since the intervals cannot be kept uniform, the insulation characteristics deteriorate, and the current situation is that both the conduction characteristics and the insulation characteristics cannot be achieved. In addition, in patent documents 2-6, since it processes with polyfunctional aziridine, a secondary amine and an unreacted amino group remain after reaction, and an anisotropic conductive film (Anisotropic Conductive Film: ACF) of a cation hardening system ) Trapped the curing agent during use, and the curing was inhibited. In addition, the aziridine compound mainly functions as a crosslinking agent and can impart solvent resistance. However, since the dispersibility of the conductive particles in the resin is not improved, aggregation in the resin is likely to occur, resulting in an insulating property. Had an influence.

(2) Coating with Insulator Particles Patent Document 7 discloses conductive particles in which the surface of a conductive particle is coated with child particles having a particle diameter smaller than that of the conductive particle and having a different charge sign from the conductive particle. Patent Document 8 discloses a patent using silica particles as child particles. When the hardness of the child particles is high, such as silica particles, there is little flatness of the insulating fine particles even when mounted under heat and pressure, and an insulating fine particle layer is generated between the gold bump and the conductive particles, or between the wiring and the conductive particles, thereby inhibiting conduction. Was. It is also described that the insulation is improved by treating with a silicone oligomer. When silicone oligomer treatment is performed using this technique, the dispersibility of the conductive particles in the film is improved. However, since an insulating film is formed on the surfaces of the child particles and the conductive particles, it has been a problem how to satisfy both the conduction characteristics and the insulation characteristics.

  Patent Documents 9, 10, and 11 disclose conductive particles coated with graft polymerization or polymer particles from the surface of the conductive particles. When the polymer is polymerized from the surface of the conductive particles, dispersibility in the ACF resin is improved, but there is a problem that the conductive resistance is increased by directly forming a film on the surface of the conductive particles. Even when the conductive particles are coated with polymer particles, since the particles synthesized in water are used, there is a problem that the dispersibility in the ACF resin is poor and aggregation is likely to occur. Furthermore, Patent Document 12 discloses insulating coated particles using particles composed of a hard particle region and a polymer resin region as child particles. However, since the polymer resin region is dissolved at the time of kneading with the ACF resin, there has been a problem that the child particles are easily separated and the insulation reliability is lowered.

  On the other hand, a method of modifying the particle (polymer particle) surface has also been proposed. Patent Document 13 discloses a method for modifying particle surfaces by reacting particles having carboxyl groups with compounds having amino groups. Although it is possible to modify the particle surface with this method, there is a problem that when the above treatment is applied to the child particles in advance, the functional group on the particle surface disappears, so that it is difficult to coat the conductive particles. It was. Patent Document 14 describes that it is possible to react a compound having an amino group with particles having a glycidyl group. However, even when this method is used, the glycidyl group disappears, so that the conductive property is reduced. It was difficult to coat the particles.

  In view of the above contents, the present invention is capable of reliably performing conductive connection between substrates, and preventing leakage between adjacent particles and obtaining good insulating properties between adjacent electrodes, An object of the present invention is to provide an anisotropic conductive material and a conductive connection structure using the conductive particles.

  As a means for solving the above conventional problems, the present inventors adsorbed the child particles to the conductive substrate particles, and then added the substrate particles, the child particles, and the compound having an amino group. As a result of the reaction, it has been found that improvement in dispersibility in the ACF resin and prevention of short circuit due to a decrease in hygroscopicity can be achieved without lowering conductivity, and the present invention has been completed.

  That is, the present invention comprises a base particle having a surface made of a conductive metal and an insulating child particle covering a part of the surface of the base particle, and at least the base particle and the child particle. One is conductive particles chemically bonded to an amino compound having a functional group equivalent of 100 to 10,000 g / mol. With such conductive particles, ion migration due to aggregation and moisture absorption in the ACF resin can be suppressed, and both conduction characteristics and insulation reliability at the time of circuit connection or the like can be achieved.

The amino compound preferably contains an alkyl chain having 6 to 18 carbon atoms. This makes it easier to adjust the hydrophobicity of the surface of the conductive particles in accordance with the target ACF, so that the aggregation of the conductive particles in the ACF resin can be more easily suppressed. From the same viewpoint, the amino compound is Ru aminosilicone der.

  The amino compound is preferably selectively chemically bonded to the inside or the surface of the child particle. Thereby, the leak between adjacent particle | grains can be prevented more reliably. Note that “selectively chemically bonded” means that the amino compound is mainly chemically bonded to the child particles, and there are some amino compounds chemically bonded to the base particles. It does not matter.

  The child particles preferably have a carboxyl group or a glycidyl group on the surface of the child particles. This facilitates the introduction of the amino compound onto the child particle surface.

  The contact angle between the surface of the film composed of the plurality of conductive particles of the present invention and water droplets is preferably 125 ° or more. Thereby, the dispersibility of the conductive particles in the ACF becomes better, and the insulating characteristics can be greatly improved.

  The monodispersion rate in the resin is preferably 50% or more. Thereby, an insulation characteristic can be improved more.

  The present invention also provides an anisotropic conductive material comprising an insulating binder resin and the conductive particles dispersed in the binder resin. Since the anisotropic conductive material contains the conductive particles of the present invention, the conductive connection between the substrates can be reliably performed, and leakage between adjacent particles can be prevented.

  Furthermore, the present invention provides a conductive connection structure that is electrically connected by the conductive particles or the anisotropic conductive material. With such a structure, the conductive connection between the substrates and the insulation between the adjacent electrodes are sufficiently ensured.

  According to the present invention, conductive particles that can reliably perform conductive connection between substrates and can prevent leakage between adjacent particles and obtain good insulating properties between adjacent electrodes, and the same conductive particles An anisotropic conductive material and a conductive connection structure can be provided.

FIG. 1 is a schematic cross-sectional view of conductive particles according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of an anisotropic conductive material including conductive particles according to an embodiment of the present invention. FIGS. 3A and 3B are schematic cross-sectional views for explaining a method for manufacturing a conductive connection structure using an anisotropic conductive material.

  Hereinafter, the best mode for carrying out the invention will be described in detail. However, the present invention is not limited to the following embodiments.

<Conductive particles>
FIG. 1 is a schematic cross-sectional view of conductive particles according to an embodiment of the present invention. As shown in FIG. 1, the conductive particle 10a of this embodiment includes a base particle 2a and a child particle 1 that covers a part of the surface of the base particle. In addition, the base material particle 2a is provided with the surface (metal layer) 12 which consists of the metal which has electroconductivity on the surface of the spherical core material particle 11 and the said core material particle. The amino compound 3 is selectively chemically bonded to the surface of the child particle 1. Since the conductive particles of this embodiment are a mode in which the base particles are partially covered with insulating child particles as described above, such conductive particles are hereinafter sometimes referred to as “insulated coated conductive particles”. .

[Base material particles]
The base particle has a surface made of a conductive metal. Such metal-coated conductive particles can be used in so-called anisotropic conductive materials for electrically connecting small electric parts such as semiconductor elements to substrates or electrically connecting substrates. As shown in FIG. 1, the base material particle of this embodiment has a metal layer 12 made of a conductive metal formed on the surface of a spherical core particle 11 made of an inorganic compound or an organic compound. It is not limited to an aspect, The metal particle which consists only of a metal which has electroconductivity may be sufficient.

  The conductive metal is not particularly limited, and gold, silver, copper, platinum, zinc, iron, tin, lead, aluminum, palladium, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium, cadmium, etc. And metal compounds such as ITO and solder.

  When the metal layer made of a conductive metal is formed on the surface of the spherical core particle made of an organic compound, the metal layer may have a single layer structure or a laminated structure made up of a plurality of layers. May be. In the case of a laminated structure, the outermost layer is preferably made of gold, palladium or nickel. When the outermost layer is made of gold, the corrosion resistance is high and the contact resistance is small, so that the obtained metal-coated conductive particles are further improved.

  The method for forming the conductive metal layer on the surface of the spherical core particles made of an organic compound is not particularly limited, and examples thereof include known methods such as physical metal vapor deposition and chemical electroless plating. Of these methods, the electroless plating method is preferable because of the simplicity of the process. Examples of the metal layer that can be formed by the electroless plating method include gold, silver, copper, platinum, palladium, nickel, rhodium, ruthenium, cobalt, tin, and alloys thereof. In the present embodiment, since a uniform coating can be formed at a high density, it is preferable that a part or all of the metal layer is formed by electroless nickel plating.

  The method for forming the gold layer on the outermost layer of the metal layer is not particularly limited, and examples thereof include known methods such as electroless plating, displacement plating, electroplating, and sputtering.

  Although the thickness of a metal layer is not specifically limited, A preferable minimum is 0.005 micrometer and a preferable upper limit is 2 micrometers. If it is less than 0.005 μm, a sufficient effect as a conductive layer may not be obtained. If it exceeds 2 μm, the specific gravity of the obtained base particles becomes too high, or the spherical core particles made of an organic compound The hardness may no longer be sufficient to deform. A more preferable lower limit is 0.01 μm, and a more preferable upper limit is 1 μm.

  Moreover, when making the outermost layer of a metal layer into a gold layer, the minimum with the preferable thickness of a gold layer is 0.001 micrometer, and a preferable upper limit is 0.5 micrometer. If the thickness is less than 0.001 μm, it may be difficult to uniformly coat the metal layer, and an effect of improving the corrosion resistance or the contact resistance value may not be expected. If the thickness exceeds 0.5 μm, the effect is expensive. is there. A more preferable lower limit is 0.01 μm, and a more preferable upper limit is 0.3 μm.

  The preferable lower limit of the particle diameter of the substrate particles is 1.0 μm, and the preferable upper limit is 10 μm. If the thickness is less than 1.0 μm, it may be difficult to maintain electrical conductivity. If the thickness exceeds 10 μm, particles may be sandwiched between the bumps, which may cause a short circuit. A more preferred lower limit is 2 μm, and a more preferred upper limit is 5 μm.

  In the present embodiment, the “particle diameter” is an average value of particle diameters when 100 target particles are observed with a scanning electron microscope (SEM).

  When the base particles are provided with spherical core particles and a metal layer, the spherical core particles are not particularly limited. For example, particles having a uniform composition and a multilayer structure in which a plurality of raw materials are configured in layers. And the like. In particular, when it is desired to impart various properties such as mechanical properties and electrical properties to the base particles, particles having a multilayer structure are preferable.

  It does not specifically limit as a material which comprises a spherical core particle, Well-known inorganic materials, such as a silica, organic materials, etc. are mentioned. In particular, when the insulating coated conductive particles of the present embodiment are used as an anisotropic conductive material, the bonding area between the surface of the base particle and the electrode may be increased by being deformed during pressure bonding when conductively connecting between the substrates. Organic materials are preferred because they are excellent in connection stability.

  Such organic material is not particularly limited, for example, polyolefins such as polyethylene, polypropylene, polystyrene, polypropylene, polyisobutylene and polybutadiene, acrylic resins such as polymethyl methacrylate and polymethyl acrylate, polyalkylene terephthalate, polysulfone, polycarbonate, Polyamide, phenol resin such as phenol formaldehyde resin, melamine resin such as melamine formaldehyde resin, benzoguanamine resin such as benzoguanamine formaldehyde resin, urea formaldehyde resin, epoxy resin, saturated polyester resin, unsaturated polyester resin, polyethylene terephthalate, polyphenylene oxide, polyacetal, Polyimide, Polyamideimide, Polyether A Ketone as well as those made of polyether sulfone. Especially, what uses the resin formed by superposing | polymerizing 1 type, or 2 or more types of various polymerizable monomers which have an ethylenically unsaturated group is preferable from being easy to obtain suitable hardness.

Specifically, as the non-crosslinkable monomer,
(I) Styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn -Butyl styrene, pt-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene , Styrenes such as p-phenylstyrene, p-chlorostyrene and 3,4-dichlorostyrene;
(Ii) Methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, dodecyl acrylate, lauryl acrylate, acrylic Stearyl acid, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, 2-methacrylic acid 2- (Meth) acrylic acid esters such as ethylhexyl, n-octyl methacrylate, dodecyl methacrylate, lauryl methacrylate and stearyl methacrylate;
(Iii) Vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl butyrate;
(Iv) N-vinyl compounds such as N-vinylpyrrole, N-vinylcarbazole, N-vinylindole and N-vinylpyrrolidone;
(V) fluorinated alkyl group-containing (meth) acrylic esters such as vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, trifluoroethyl acrylate and tetrafluoropropyl acrylate; and (vi) butadiene And conjugated dienes such as isoprene.

Further, as a crosslinkable monomer, specific examples are as follows:
Divinylbenzene;
Divinylbiphenyl;
Divinyl naphthalene;
(Poly) alkylene glycol di (meth) acrylates such as (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate and (poly) tetramethylene glycol di (meth) acrylate;
1,6-hexanediol di (meth) acrylate, 1,8-octanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, 1, 12-dodecanediol di (meth) acrylate, 3-methyl-1,5-pentanediol di (meth) acrylate, 2,4-diethyl-1,5-pentanediol di (meth) acrylate, butylethylpropanediol di ( Alkanediol-based di (meth) acrylates such as (meth) acrylate, 3-methyl-1,7-octanediol di (meth) acrylate and 2-methyl-1,8-octanediol di (meth) acrylate;
Neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolpropane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, ethoxylated cyclohexanedimethanoldi (Meth) acrylate, ethoxylated bisphenol A di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, propoxylated ethoxylated bisphenol A di (meth) acrylate, 1,1,1-trishydroxymethylethanedi ( (Meth) acrylate, 1,1,1-trishydroxymethylethane tri (meth) acrylate, 1,1,1-trishydroxymethylpropane triacrylate, diallyl lid Over preparative and its isomers as well as triallyl isocyanurate and derivatives thereof. In addition, as a product, 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.

  Furthermore, a monomer having a silyl group can also be used as the crosslinkable monomer. Specifically, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-methacryloxypropylbis (trimethoxy) methylsilane, 11-methacryloxyundecamethylenetrimethoxysilane, vinyltriethoxysilane, 4-vinyltetra Methylenetrimethoxysilane, 8-vinyloctamethylenetrimethoxysilane, 3-trimethoxysilylpropyl vinyl ether, vinyltriacetoxysilane, p-trimethoxysilylstyrene, p-triethoxy Silylstyrene, p-trimethoxysilyl-α-methylstyrene, p-triethoxysilyl-α-methylstyrene, γ-acryloxypropyltrimethoxysilane, vinyltrimethoxysilane and N-β (N-vinylbenzylaminoethyl- γ-aminopropyl) trimethoxysilane hydrochloride.

  Moreover, the said monomer may be used 1 type or in mixture of 2 or more types. As a method for producing such particles, a conventionally known method can be used and is not particularly limited. However, emulsion polymerization, phase inversion emulsion polymerization, suspension polymerization, dispersion polymerization, seed polymerization, and soap-free emulsion weight are not particularly limited. Legal etc. are mentioned. Among these, a seed polymerization method that is excellent in controlling the particle diameter is preferable.

[Child particles]
In the insulating coated conductive particles of this embodiment, insulating child particles are supported on the surface of the base material particles. That is, a part of the surface of the substrate particle is covered with a plurality of child particles carried on the surface of the substrate particle. In addition, it is preferable that a child particle has a functional group for reacting with the compound (amino compound) which has an amino group. Although it does not specifically limit as a material which comprises a child particle, It is preferable that it has insulation, and it is preferable to contain the compound which has a silyl group and a double bond from a viewpoint of solvent resistance. Since the thermal characteristics can be adjusted by appropriately selecting the type of material constituting the child particles, the particles are easily deformed, and the conductivity is improved when the substrates are pressed. A child particle may be used independently and 2 or more types may be used together. The production method of the child particles (cross-linked spherical polymer fine particles) of the present embodiment is not particularly limited, and known methods such as an emulsion polymerization method, a soap-free emulsion polymerization method, a micro suspension polymerization method, a mini-emulsion polymerization method, and a dispersion polymerization method are used. it can. Among these, it is preferable to produce the particles by precipitation polymerization or a soap-free emulsion polymerization method from the viewpoint of easy control of the particle size and suitability for industrial production.

  In such a polymerization method, the content of the polymerizable monomer in the reaction solution is preferably 1 to 50% by mass in the total reaction solution, more preferably 2 to 30% by mass, and most preferably 3 to 20% by mass. It is. In such a polymerization method, even if the amount of monomer in the reaction system is increased, the aggregate of particles does not increase extremely. However, if the content of the raw material monomer exceeds 50% by mass, the particles are monodispersed. It becomes difficult to obtain a high yield in a converted state. On the other hand, if it is less than 1% by mass, it takes a long time to complete the reaction, and it is not practical from an industrial viewpoint.

  The reaction temperature at the time of polymerization varies depending on the type of solvent to be used and cannot be generally defined, but is usually about 10 to 200 ° C, preferably 30 to 130 ° C, more preferably 40 to 90 ° C. It is. In addition, the reaction time is not particularly limited as long as it is a time required for the target reaction to be almost completed, and the monomer species and the blending amount thereof, the type of functional group, the viscosity of the solution, the concentration thereof, and the target For example, in the case of 40 to 90 ° C., it is 1 to 72 hours, preferably about 2 to 24 hours.

  The child particles preferably have a functional group on the surface capable of reacting with an amino group-containing polymer (amino compound). Examples of such functional groups include a carboxyl group, an epoxy group, a glycidyl group, a carboxylic acid anhydride, and a sulfonium group. Among these functional groups, when the reaction with the amino group is fast, there is a possibility of inducing aggregation of the particles. Therefore, it is preferable to use a carboxyl group, an epoxy group or a glycidyl group. In order to obtain child particles having these functional groups, monomers containing these functional groups may be copolymerized.

Specific examples of the monomer having a carboxyl group include the following.
(1) Carboxy group-containing polymerizable monomer Unsaturated carboxylic acid such as acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, itaconic acid, maleic acid and fumaric acid, monoalkyl itaconate such as monobutyl itaconate (carbon number 1) -8) Various carboxyl group-containing monomers such as esters, monoalkyl maleates (1-8 carbon atoms) such as monobutyl maleate and vinyl group-containing aromatic carboxylic acids such as vinyl benzoic acid, and salts thereof. Can be mentioned. In addition, these compounds can be used individually by 1 type or in combination of 2 or more types, You may have counter ions, such as Na, by neutralization. These compounds are preferably used in an amount of 0.1 mol% to 10 mol% in order to improve the monodispersity of the child particles. More preferably, it is 0.1 mol% to 3 mol%.

Specific monomers having an epoxy group or a glycidyl group include the following.
(2) Epoxy group, glycidyl group-containing polymerizable monomer glycidyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether, N- [4- (2,3-epoxypropan-1-yloxy) -3,5 -Dimethylbenzyl] acrylamide, acrylic acid 9,10-epoxyoctadecanoic anhydride, acrylic acid (7-oxabicyclo [4.1.0] heptan-3-yl) methyl and acrylic acid = 3,4-epoxytricyclo [5.2.1.02,6] decyl and the like. Moreover, the macromonomer which contains many epoxy groups can also be used. These compounds are preferably used in an amount of 1 mol% to 10 mol% in order to introduce a hydrophobic group on the surface of the child particles. Moreover, in order to introduce efficiently to the child particle surface, a method of seed polymerization of the above monomer with respect to a particle synthesized in advance can be mentioned.

For the copolymerization of such monomers, for example, the following initiators can be used.
2′-azobis {2- [N- (2-carboxyethyl) amidinopropane, 2,2′-azobis [2- (phenylamidino) propane] dihydrochloride (VA-545, manufactured by Wako Pure Chemical Industries), 2,2 '-Azobis {2- [N- (4-chlorophenyl) amidino] propane} dihydrochloride (VA-546, manufactured by Wako Pure Chemical Industries), 2,2'-azobis {2- [N- (4-droxyphenyl) Amidino] propane} dihydrochloride (VA-548, manufactured by Wako Pure Chemical Industries), 2,2′-azobis [2- (N-benzylamidino) propane] dihydrochloride (VA-552, manufactured by Wako Pure Chemical Industries), 2,2 '-Azobis [2- (N-allylamidino) propane] dihydrochloride (VA-553, manufactured by Wako Pure Chemical Industries), 2,2'-azobis (2-amidinopropane) dihydrochloride (V- 50, manufactured by Wako Pure Chemical Industries, Ltd.), 2,2′-azobis {2- [N- (4-hydroxyethyl) amidino] propane} dihydrochloride (VA-558, manufactured by Wako Pure Chemical Industries), 2,2-azobis [2 -(5-Methyl-2-imidazolin-2-yl) propane] dihydrochloride (VA-041, manufactured by Wako Pure Chemical Industries), 2,2-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride (VA-044, manufactured by Wako Pure Chemical Industries), 2,2-azobis [2- (4,5,6,7-tetrahydro-1H-1,3-diazepin-2-yl) propane] dihydrochloride (VA-054) , Wako Pure Chemical), 2,2-azobis [2- (3,4,5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride (VA-058, manufactured by Wako Pure Chemical), 2,2- Azobis [2- ( 5-hydroxy-3,4,5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride (VA-059, manufactured by Wako Pure Chemical Industries), 2,2-azobis {2- [1- (2-hydroxyethyl) ) -2-imidazolin-2-yl] propane} dihydrochloride (VA-060, manufactured by Wako Pure Chemical Industries), 2,2-azobis [2- (2-imidazolin-2-yl) propane] (VA-061, sum) Manufactured by Kojun Pharmaceutical Co., Ltd.), 2,2′-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] (VA-057, manufactured by Wako Pure Chemical Industries), potassium peroxodisulfate (manufactured by Wako Pure Chemical Industries), and peroxo An ammonium disulfate (made by Wako Pure Chemical Industries) is mentioned. These can be used individually by 1 type or in combination of 2 or more types. The amount of the radical polymerization initiator is usually 0.1 to 10 mol%, preferably 0.1 to 5 mol%, more preferably 0.1 to 2 mol%, based on 100 mol% of the polymerizable monomer. . A functional group may be imparted by a polymer dispersant or a surfactant.

  An emulsifier can be used in combination to improve the dispersibility of the child particles. Examples of the emulsifier that can be used in the present embodiment include an anionic emulsifier and a nonionic emulsifier. Specific examples of the anionic emulsifier include sodium alkylbenzene sulfonate, sodium lauryl sulfonate, and potassium oleate. Particularly, sodium dodecylbenzene sulfonate is preferably used. Specific examples of nonionic emulsifiers include polyoxyethylene nonylphenyl ether and polyoxyethylene lauryl ether.

  The Tg (glass transition point) of the child particles can be arbitrarily adjusted by selecting a polymerizable monomer to be used and by copolymerizing two or more polymerizable monomers having different Tg. For example, isobutyl methacrylate, glycidyl methacrylate, etc. are mentioned as a polymerizable monomer which Tg or softening point temperature becomes 60 degrees C or less independently. Moreover, Tg can be 60 degrees C or less by copolymerizing styrene, methyl methacrylate, etc. whose Tg is 60 degreeC or more, and butyl acrylate, dodecyl methacrylate, etc. whose Tg is less than 60 degreeC. Examples of the resin having a Tg of 80 ° C. or higher include styrene, α-methylstyrene, methyl methacrylate, and t-butyl methacrylate. These may be used independently and 2 or more types may be used together.

  The particle diameter of the child particles varies depending on the particle diameter of the base particle and the use of the insulating coated conductive particles of the present embodiment, but is preferably 100 to 500 nm. If it is less than 100 nm, the distance between adjacent insulating coating conductive particles becomes smaller than the hopping distance of electrons, and leakage may easily occur. On the other hand, if it exceeds 500 nm, the conduction resistance may become too large during mounting at a low pressure. In addition to this, when it exceeds 500 nm, the physical properties of the base particles may be governed by the physical properties of the child particles, and the effect of using the base particles becomes difficult to obtain. More preferably, the lower limit of the particle diameter of the child particles is 150 nm, and the upper limit is 400 nm.

  It should be noted that two or more kinds of child particles having different particle diameters may be used in combination because the small child particles enter the gaps between the large child particles carried on the base particles and the coating density can be improved. At this time, the particle size of the small child particles is preferably 1/2 or less of the particle size of the large child particles, and the number of small child particles is preferably 1/4 or less of the number of large child particles. .

The child particles preferably have a CV value (coefficient of variation) of the particle diameter of 10% or less. If it exceeds 10%, the size of the resulting insulating coated conductive particles becomes non-uniform, and when used for anisotropic conductive materials, it becomes difficult to apply pressure uniformly when crimping between substrates, resulting in poor conductive connection. Sometimes. The CV value is more preferably 7% or less, and most preferably 5% or less. In addition, the CV value of the particle diameter of the child particles can be calculated by the following formula (1).
CV value of particle diameter (%) = standard deviation of particle diameter / average particle diameter × 100 (1)
The particle size CV value of the child particles can be measured with a particle size distribution meter or the like before being supported on the substrate particles, but can be measured by image analysis of an SEM photograph after being supported on the substrate particles.

  In the insulating coated conductive particles of the present embodiment, such child particles are supported on the surface of the base particle, and the child particles have a surface area of 20% or less in contact with the surface of the base particle. preferable. If it exceeds 20%, the deformation of the child particles will be large, and the size of the resulting insulating coated conductive particles will be non-uniform or the structure will not be maintained. The lower limit is not particularly limited, and may be substantially 0% when the child particles and the base particle are bound by, for example, a polymer having a long chain length.

In the insulating coated conductive particles of the present embodiment, the coverage defined by the following formula (2) (the ratio of the child particles to the surface of the base particles) is preferably 5% or more. The coverage is obtained by preparing 100 SEM images of base particles having child particles adsorbed on the surface and analyzing the center part of the base particles (circle having a diameter of 2 μm).
Coverage (%) = {(area of the portion covered with the child particles on the surface of the base particle) / (total surface area of the base particle)} × 100 (2)

  When the insulating coated conductive particles of this embodiment are used for an anisotropic conductive material, the preferable lower limit of the coating density is 5%, and the preferable upper limit is 60%. If it is less than 5%, the metal surfaces of the base particles come into contact with each other between adjacent particles, so that lateral leakage tends to occur and insulation may not be ensured. On the other hand, if it exceeds 60%, sufficient conductivity may not be ensured. The coverage by the child particles on the surface of the substrate particles can be controlled by the amount (concentration) of the child particles added, the amount of functional groups (density) introduced to the surface of the substrate particles, the type of reaction solvent, and the like.

  In addition, when an ammonium ion elutes from the insulation coating conductive particle of this embodiment, hardening inhibition of an anisotropic conductive film occurs. Therefore, the elution amount of ammonium ions from the insulating coated conductive particles is preferably 100 ppm or less.

[Amino compound]
In order to improve the dispersibility of the conductive particles in the ACF resin, the conductive particles including the base particles and the child particles are treated with an amino compound having a functional group equivalent of 100 to 10,000 g / mol. If the amino compound is introduced into the surface of the conductive particles, the dispersibility thereof can be improved. In particular, it is preferable that the amino compound is selectively introduced into the inside or the surface of the child particle. When the functional group equivalent exceeds 10,000 g / mol, fusion tends to occur when the insulating coated conductive particles are dried, and when the functional group equivalent is less than 100 g / mol, dispersibility in the ACF resin becomes insufficient. Tend. The functional group equivalent is preferably 100 to 3000 g / mol, and more preferably 150 to 3000 g / mol. Such an amino compound is not particularly limited, but when the child particles have a carboxyl group, an epoxy group or a glycidyl group, those capable of reacting with these functional groups to form a chemical bond well are preferable. When the steric hindrance is large, the amino compound preferably has a primary amino group rather than a secondary amino group in terms of reactivity. In addition, the coupling | bonding to the child particle | grains of an amine can be confirmed by the composition analysis based on pyrolysis GC-MASS (Gas Chromatography Mass Spectrometry), for example. The location of amine adsorption on the child particles is identified by the identification of nitrogen atoms based on SEM-EDX (Energy Dispersive X-ray Spectroscopy), and GC-MASS on the child particles exfoliated from the substrate particles.

  The amino compound preferably contains an alkyl chain having 6 to 18 carbon atoms, and more preferably has a hydrophobic group. In addition, as for carbon number, it is more preferable that it is 12-18. For example, the amino compound having a primary amino group and a hydrophobic group includes 1-hexylamine, 1-octaneamine, 1-nonaneamine, 1-decanamine, 1-aminoundecane, 1-dodecylamine, 1-aminotridecane, Examples include 1-aminopentadecane, 1-aminohexadecane, 1-aminoheptadecane, and 1-octadecylamine. In addition to the above, aminosilicones (amino-modified silicone), polymers having an amino group at the terminal, and the like can be used as the amino compound. For example, when the child particles have a carboxyl group, these amino compounds are preferably used in an amount of 1.2 to 3 times the carboxyl group.

  In addition, when a child particle has a carboxyl group, an epoxy group, or a glycidyl group, reaction of these functional groups and an amino compound (amino group) is performed by using a condensing agent. Specific condensing agents include dicyclohexylcarbodiimide, diisopropylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide and 4 (-4,6-Dimethoxy-1,3,5-triazin-2-yl). -4-methylmorpholine Chloride (DMT-MM) and the like, and it is preferable to use DMT-MM from the viewpoint that reactivity, a solvent such as alcohol and water can be used.

  In addition, the contact angle between the surface of the film composed of the plurality of insulating coated conductive particles of the present embodiment and the water droplets is preferably 125 ° or more, and more preferably 130 ° or more. Such a measurement of the contact angle can be performed as follows, for example. First, after sticking one side of a double-sided tape (Nitto Denko No. 500) to a glass substrate and spraying multiple (suitable amount) of insulating coating conductive particles excessively on the other surface, excluding excessively adsorbed insulating coating conductive particles, A film composed of insulating coated conductive particles is formed. Then, 3 μL of water droplets are dropped on the membrane, and the contact angle between the membrane and the water droplets is measured by the θ / 2 method. If the insulating coated conductive particles have a contact angle of 125 ° or more at this time, the dispersibility in the ACF becomes better, and the insulating characteristics can be greatly improved.

  The insulating coated conductive particles of the present embodiment preferably have a monodispersion rate in the resin (for example, in the ACF resin) of 50% or more, and more preferably 60% or more. Here, the monodispersion rate refers to the proportion of particles that are not aggregated and exist as a single particle among all the insulating coated conductive particles in the resin. Specifically, it can be measured by observing an anisotropic conductive material described later using a Keyence optical microscope (VH-Z450). Insulating coated conductive particles having a monodispersion rate of 50% or more can further improve the insulating properties.

<Anisotropic conductive material>
FIG. 2 is a schematic cross-sectional view of an anisotropic conductive material including conductive particles (insulating coated conductive particles) according to this embodiment. That is, the anisotropic conductive material 40 includes an insulating binder resin 20 and the conductive particles 10 dispersed in the binder resin. In FIG. 2, amino compound 3 is omitted for simplification of the drawing.

  As the binder resin 20 used for the anisotropic conductive material 40, a mixture of a thermally reactive resin and a curing agent is used, and specifically, a mixture of an epoxy resin and a latent curing agent is preferable.

  Epoxy resins include bisphenol type epoxy resins derived from epichlorohydrin and bisphenol A, F, AD, etc., epoxy novolac resins derived from epichlorohydrin and phenol novolac or cresol novolac, and naphthalene type epoxy resins having a skeleton containing a naphthalene ring. , Various epoxy compounds having two or more glycidyl groups in one molecule such as glycidylamine, glycidyl ether, biphenyl, and alicyclic can be used alone or in admixture of two or more.

These epoxy resins, impurity ions ^(Na +, Cl ^-, etc.) and, it is preferable to use a high purity which is reduced to 300ppm or less hydrolyzable chlorine and the like. This makes it easier to prevent electromigration.

  Examples of the latent curing agent include imidazole series, hydrazide series, boron trifluoride-amine complex, sulfonium salt, amine imide, polyamine salt, dicyandiamide, and the like. In addition, an energy ray curable resin such as a mixture of a radical reactive resin and an organic peroxide or ultraviolet rays is used for the adhesive.

  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 bonding or to improve adhesiveness.

  The binder resin 20 is a paste or film. In order to make the adhesive into a film, it is effective to blend a thermoplastic resin such as a phenoxy resin, a polyester resin, or a polyamide resin. These film-forming polymers are also effective in stress relaxation when the reactive resin is cured. In particular, when the film-forming polymer has a functional group such as a hydroxyl group, the adhesiveness is improved, which is more preferable.

  The anisotropic conductive material 40 can be manufactured as follows, for example. First, a binder resin 20 is prepared by liquefying a composition containing an epoxy resin, an acrylic rubber, a latent curing agent, a film-forming polymer, and the like by dissolving or dispersing the composition in an organic solvent. A mixed solution in which the insulating coated conductive particles 10 are dispersed is prepared. The organic solvent used at this time is preferably an aromatic hydrocarbon-based and oxygen-containing mixed solvent in terms of improving the solubility of the material. And after applying this liquid mixture on a release film with a roll coater etc., removing a solvent below the active temperature of a hardening | curing agent, it can obtain by peeling from a release film. As the releasable film, a PET film or the like surface-treated so as to have releasability is preferably used. In addition, although the anisotropic conductive material of this embodiment is a film form, the shape of an anisotropic conductive material is not limited to a film form.

  The thickness of the anisotropic conductive material 40 is relatively determined in consideration of the particle size of the insulating coated conductive particles 10 and the characteristics of the anisotropic conductive material 40, and is preferably 1 to 100 μm. If it is less than 1 μm, sufficient adhesion cannot be obtained, and if it exceeds 100 μm, a large amount of insulating coated conductive particles 10 are required to obtain conductivity, which is not realistic. For these reasons, the thickness is more preferably 3 to 50 μm.

<Conductive connection structure>
FIGS. 3A and 3B are schematic cross-sectional views for explaining a method for manufacturing a conductive connection structure using an anisotropic conductive material. The conductive connection structure 42 of the present embodiment is electrically connected by the anisotropic conductive material 40. In FIGS. 3A and 3B, the amino compound 3 is omitted for simplification of the drawing.

  In the conductive connection structure 42, first, as shown in FIG. 3A, the first substrate 4 and the second substrate 6 are prepared, and the anisotropic conductive material 40 is disposed therebetween. At this time, the position is adjusted so that the first electrode 5 included in the first substrate 4 and the second electrode 7 included in the second substrate 6 face each other. Thereafter, the first substrate 4 and the second substrate 6 are laminated while being heated under pressure in a direction in which the first electrode 5 and the second electrode 7 face each other, and the conductive connection shown in FIG. A structure 42 is obtained.

  When the conductive connection structure 42 is produced in this manner, conductivity between the opposing electrodes (longitudinal direction) is ensured through the base particle 2, and between adjacent electrodes (lateral direction) is the base particle 2. The insulating property is maintained by interposing the child particles 1 having the amino compound 3 (not shown) therebetween.

  In recent years, anisotropic conductive materials for COG have been required to have insulation reliability at a narrow pitch of 10 μm level. However, if the anisotropic conductive material 40 according to this embodiment is used, insulation reliability at a narrow pitch of 10 μm level is required. It becomes possible to improve the property.

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

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is not limited to the following Example.

[Preparation of child particles]
(Synthesis of child particle 1)
Each compound shown below was charged all at once into a 500 ml flask, and after replacing the dissolved oxygen with nitrogen for 1 h, the mixture was heated and stirred at a water bath temperature of 70 ° C. for about 6 hours to obtain child particles 1. When the child particles 1 were observed by SEM, the particle diameter was 310 nm and the particle diameter CV was 3.5%.
Styrene: 600 mmol
Sodium methacrylate: 6.0 mmol
KBM-503: 3.6 mmol
Potassium peroxodisulfate: 5.4 mmol
Divinylbenzene: 14.4 mmol
Water: 400g

(Synthesis of child particle 2)
Each compound shown below was charged all at once into a 500 ml flask, and after replacing the dissolved oxygen with nitrogen for 1 h, the mixture was heated and stirred at a water bath temperature of 70 ° C. for about 6 hours to obtain particles. When the particles were observed by SEM, the particle size was 281 nm and the particle size CV was 3.0%.
Styrene: 600 mmol
Sodium styrenesulfonate: 1.5mmol
KBM-503: 3.6 mmol
Potassium peroxodisulfate: 5.4 mmol
Divinylbenzene: 14.4 mmol
Water: 400g
The following monomer was additionally added to the liquid in which the synthesized particles were dispersed, and heating and stirring were continued at 70 ° C. for 6 hours to synthesize child particles 2 coated with glycidyl groups.
Glycidyl methacrylate: 60mmol
Potassium peroxodisulfate: 0.06mmol
When the child particles 2 after synthesis were observed with an SEM, the particle size was 315 nm and the particle size CV was 3.3%.

(Synthesis of child particles 3)
Each compound shown below was charged all at once into a 500 ml flask, and the dissolved oxygen was replaced with nitrogen for 1 h, followed by heating and stirring at a water bath temperature of 70 ° C. for about 6 hours to obtain child particles 3. When the child particles 3 were observed by SEM, the particle size was 320 nm and the particle size CV was 3.0%. Further, after purification by centrifugation, neutralization titration of the particle dispersion was performed using KOH, and the acid value of the child particles 3 was 5 mgKOH / g.
Styrene: 600 mmol
Methacrylic acid: 6mmol
Sodium styrenesulfonate: 1.5mmol
Potassium peroxodisulfate: 5.4 mmol
Water: 400g

(Synthesis of child particles 4)
150 g of a 0.25 wt% aqueous sodium dodecyl sulfate solution was added to 200 g of the dispersion (10 wt%) of the child particles 1, and the temperature was raised to 72.5 ° C. To this, 0.2 g of potassium peroxodisulfate was added, and further 30 minutes later, 20 g of a monomer mixture obtained by mixing 10 g of styrene and methyl methacrylate was gradually dropped over 3 hours to carry out polymerization. After the addition of the monomer, the reaction was further allowed to proceed for 3 hours to obtain a mixed solution containing child particles 4 that were core-shell particles having poly (ST-MMA) as a shell. Unreacted substances and emulsifiers were removed from the mixed solution using a centrifuge. When the child particles 4 were observed by SEM, the particle diameter was 387 nm and the particle diameter was CV 3.8%.

  The child particles 1 to 4 are collectively shown in Table 1 below.

[Preparation of substrate particles]
A nickel layer having a thickness of 0.2 μm is formed by electroless plating on the surface of the crosslinked polystyrene particles having an average particle diameter of 3.0 μm, and a palladium layer having a thickness of 0.04 μm is further formed on the outer side of the nickel. Base material particles were obtained.

[Preparation of insulating coated conductive particles]
Insulation-coated conductive particles 1 to 11 were produced according to the following Evaluation Examples 1 to 11.

(Evaluation example 1)
(Coating substrate particles with child particles)
Mercaptoacetic acid 8 mmol was dissolved in methanol 200 mL to prepare a reaction solution. 10 g of the base particles were added to the reaction solution, and stirred at room temperature for 2 hours using a three-one motor and a stirring blade having a diameter of 45 mm, and the surface of the base particles was treated with mercaptoacetic acid. The treated base particles were taken out by filtration using a φ3 μm membrane filter (Millipore), and the taken base particles were washed with methanol to obtain 10 g of base particles having a carboxyl group on the surface.

  On the other hand, a 30% polyethyleneimine aqueous solution (manufactured by Wako Pure Chemical Industries, Ltd.) having a molecular weight of 70,000 was diluted with ultrapure water to obtain a 0.3 mass% polyethyleneimine aqueous solution. To this polyethyleneimine aqueous solution, 1 g of base particles having a carboxyl group on the surface obtained above was added and stirred at room temperature for 15 minutes. Next, the base particles were taken out by filtration using a φ3 μm membrane filter (Millipore), and the taken base particles were put in 200 g of ultrapure water and stirred at room temperature for 5 minutes. Thereafter, the base particles are taken out by filtration using a φ3 μm membrane filter (Millipore), and the base particles on the membrane filter are washed twice with 200 g of ultrapure water to remove non-adsorbed polyethyleneimine. did. Through the above operation, substrate particles having polyethyleneimine adsorbed on the surface were obtained.

  Next, the base material particles treated with polyethyleneimine were immersed in isopropyl alcohol, and the dispersion liquid of the child particles 1 was dropped to obtain base particles having a part of the surface coated with the child particles. The coverage (coating density) of the child particles on the surface of the substrate particles was 30%. Hereinafter, the substrate particles coated with the child particles are referred to as “child particle-coated substrate particles”. The coating density was adjusted by the dropping amount of the dispersion liquid of the child particles 1. Next, the child particle-coated conductive particles were taken out by filtration using a φ3 μm membrane filter (manufactured by Millipore), and placed in 200 g of the extracted child particle-coated substrate particles ultrapure water and stirred at room temperature for 5 minutes. Thereafter, the child particle-coated substrate particles are removed by filtration using a φ3 μm membrane filter (Millipore), and the child particle-coated substrate particles on the membrane filter are washed twice with 200 g of ultrapure water. Child particles not adsorbed on the particles were removed.

(Hydrophobic treatment)
While stirring 3 g of the obtained child particle-coated substrate particles in 30 g of methanol, 0.2 g of DMT-MM and 0.147 g of hexylamine which is an amino compound were added, and stirring was continued for 1 hour. Thereafter, washing with methanol and filtration were repeated three times, and then the insulating coated conductive particles were vacuum dried at 60 ° C. for 1 hour to obtain insulating coated conductive particles 1 of Evaluation Example 1. The hexylamine was selectively chemically bonded to the carboxyl group of the child particle 1.

(Contact angle measurement of insulating coated conductive particles)
After sticking a double-sided tape (Nitto Denko No. 500) on the slide glass, the produced plurality of insulating coated conductive particles 1 were sprayed. Then, after removing the excess insulation coating conductive particles 1, a film composed of the insulation coating conductive particles 1 was obtained. A 3 μL water droplet was dropped on the membrane, and the contact angle of water on the membrane was measured.

(Solvent resistance test of insulating coated conductive particles)
The obtained insulating coated conductive particles 1 were immersed in a toluene / ethyl acetate (5/5 wt%) solution, and after 5 minutes of ultrasonic irradiation (24 kHz), the insulating coated conductive particles 1 were observed with an SEM, and the child particles were removed. It was confirmed whether it was separated. The case where there was no change in the adsorption amount of the child particles was designated as A, and the case where the child particles were partially detached was designated as B.

(Evaluation example 2)
In the hydrophobization treatment in Evaluation Example 1, the insulating coated conductive particles 2 were obtained in the same manner except that an equimolar amount of dodecylamine was used instead of hexylamine. The dodecylamine was selectively chemically bonded to the carboxyl group of the child particle 1.

(Evaluation example 3)
In the hydrophobization treatment in Evaluation Example 1, the insulating coated conductive particles 3 were obtained in the same manner except that an equimolar amount of octadecylamine was used instead of hexylamine. Note that octadecylamine was selectively chemically bonded to the carboxyl group of the child particle 1.

(Evaluation example 4)
In the hydrophobization treatment of Evaluation Example 1, the same procedure was performed except that amino-modified silicone (TSF4700: Momentive) was used in the same amount as amino acid equivalent to hexylamine instead of hexylamine, and insulating coated conductive particles 4 were obtained. The amino-modified silicone was selectively chemically bonded to the carboxyl group of the child particle 1.

(Evaluation example 5)
In the hydrophobization treatment of Evaluation Example 1, the same procedure was performed except that amino-modified silicone (TSF4709: Momentive) was used in an equivalent amount of amino equivalent to hexylamine instead of hexylamine, to obtain insulating coated conductive particles 5. The amino-modified silicone was selectively chemically bonded to the carboxyl group of the child particle 1.

(Evaluation example 6)
In the evaluation example 3, the child particles 2 were used in place of the child particles 1 and the same was performed except that the hydrophobization treatment was performed at 80 ° C. for 1 hour, whereby the insulating coated conductive particles 6 were obtained. The octadecylamine was selectively chemically bonded to the glycidyl group of the child particle 2.

(Evaluation example 7)
In Evaluation Example 1, the child particles 3 were used in place of the child particles 1, and the conductive particles were coated in the following manner, except that the hydrophobic treatment was not performed. Got.
(Conductive particle coating of conductive particles)
A 0.2 μm film was formed on the conductive particles by hybridization using the child particles 3 to obtain child particle-coated conductive particles. Then, a solution obtained by dissolving 5 parts by weight of trimethylolpropane-tri-β-aziridinylpropionate (TAZM) in 95 parts by weight of ethanol is sprayed evenly onto the child particle-coated conductive particles obtained above. A cross-linking reaction was performed by heating and drying at 100 ° C. to obtain insulating coated conductive particles.

(Evaluation example 8)
Insulating coated conductive particles 8 were obtained in the same manner except that the hydrophobic treatment in Evaluation Example 1 was performed as follows.
(Hydrophobic treatment)
10 g of the insulating coated conductive particles after drying is put into 100 g of a treatment solution in which the same amount of silicone oligomer (Shin-Etsu Chemical KR-212) as the mass of the insulating coated conductive particles is dissolved, and a three-one motor is used under conditions of room temperature for 1 hour. And stirred. Thereafter, the particles were removed by filtration, and the taken-out insulating coated conductive particles were washed with methanol and dried to obtain insulating coated conductive particles having a silicone oligomer attached to the surface.

(Evaluation example 9)
In Evaluation Example 1, the same procedure was performed except that the hydrophobic treatment was not performed, and insulating coated conductive particles 9 were obtained.

(Evaluation example 10)
In evaluation example 1, the child particles 4 were used in place of the child particles 1, and the same procedure was performed except that the hydrophobization treatment was not performed, whereby insulating coated conductive particles 10 were obtained.

(Evaluation example 11)
In the hydrophobization treatment in Evaluation Example 1, the insulating coated conductive particles 11 were obtained in the same manner except that equimolar amounts of butylamine were used instead of hexylamine.

  The insulating coated conductive particles 1 to 11 of Evaluation Examples 1 to 15 are collectively shown in Table 2 below.

[Production of anisotropic conductive material]
Next, anisotropic conductive materials 1 to 11 were produced using the insulating coated conductive particles 1 to 11.

  5 parts by mass of phenoxy resin (Union Carbide: PKHC) anisotropic conductive material total amount, 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) Polymer, dissolved in 18 parts by mass of weight average molecular weight: 850,000), 15 parts by mass of epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd .: YL-983U) and 10 parts by mass of ethyl acetate to obtain a solution having a polymer concentration of 30% by mass It was.

  2 parts by mass of a cationic curing agent (manufactured by Sanshin Chemical Industry Co., Ltd .: SI-60) was added to this solution to prepare an adhesive solution. 30 parts by mass of an ethyl acetate dispersion (10 parts by mass) of silica filler (Nippon Aerosil Co., Ltd .: Aerosil R805) was added and stirred. Thereafter, 20 parts by mass of the insulating coated conductive particles were mixed with ethyl acetate and subjected to ultrasonic dispersion. This dispersion was applied to a silicone-treated polyethylene terephthalate film separator (thickness 40 μm) with a roll coater and dried at 80 ° C. for 5 minutes to produce a film-like anisotropic conductive material having a thickness of 23 μm.

  Moreover, the emitted-heat amount and monodispersion rate of the anisotropically conductive materials 1-11 obtained were evaluated as follows, respectively. The evaluation results are summarized in Table 3.

(Measurement of calorific value)
10 mg of anisotropic conductive material was cut out, placed in an aluminum cell, and sealed under pressure. Then, it measured in the range of 40 to 250 degreeC by DSC (product made from TA Instruments: Q1000) with the temperature increase rate of 10 degree-C / min. At this time, according to the following formula (3), the case where the measured partial calorific value was 80 J / g or more was A, 60 to 80 J / g was B, and 60 J / g or less was C.
Partial calorific value = h1 / (h1 + h2) × 100 (3)
h1: Calorific value (J / g) of the first peak (around 100 to 150 ° C.)
h2: calorific value (J / g) of the second peak (around 200 to 250 ° C.)

(Measurement of monodispersion)
First, a film-like material that does not contain insulating coated conductive particles in the production of the anisotropic conductive material is produced. And what cut out the anisotropic conductive material at 1 mm square is put on what cut out this film-form material into 3 mm square. This was rolled using Toray Engineering Co., Ltd. high-definition automatic bonder (FC-1200) at 80 ° C. for 40 seconds with a load of 13 kgf, and further rolled at 200 ° C. for 20 seconds with a load of 13 kgf. It was. Then, the film rolled using a Keyence optical microscope (VH-Z450) was imaged at 20 locations at 1000 times, and this was subjected to image processing, thereby aggregating the total number of electrically insulating coated conductive particles in the photograph. The ratio (monodispersity) of the insulating coated conductive particles present alone was measured. The case where the monodispersion rate was 70% or more was A, the case where it was 50 to 70% was B, and the case where it was 50% or less was C.

[Production of conductive connection structure]
Next, conductive connection structures 1 to 11 were produced using the produced film-like anisotropic conductive materials 1 to 11.

  Using anisotropic conductive material, gold bumps (area: 30 μm × 90 μm, space 10 μm, height: 15 μm, number of bumps: 362) chip (1.7 mm × 17 mm, thickness: 0.5 mm) and glass with ITO circuit Connection with a substrate (Geomatec, thickness: 0.7 mm) was performed as follows to obtain a conductive connection structure.

That is, the anisotropic surface cut to a predetermined size (2 mm × 19 mm) with the surface opposite to the surface provided with the separator of anisotropic conductive material facing the surface on which the ITO circuit of the glass substrate with ITO circuit is formed The conductive material was attached to the surface of a glass substrate with an ITO circuit at 80 ° C. and 0.98 MPa (10 kgf / cm ² ). Thereafter, the separator was peeled off from the anisotropic conductive material attached to the glass substrate with ITO circuit, and the gold bumps of the chip and the glass substrate with ITO circuit were aligned through the anisotropic conductive material. Next, the surface on which the gold bumps of the chip are provided is directed to the surface opposite to the surface on which the glass substrate with an ITO circuit made of anisotropic conductive material is attached, and heated at 170 ° C., 70 MPa for 5 seconds. This connection was made by applying pressure to obtain a mounting sample (conductive connection structure).

(Insulation resistance test and conduction resistance test)
The insulation resistance test and conduction resistance test of the mounting samples (conductive connection structures 1 to 11) produced above were performed as follows. The evaluation results are summarized in Table 3.

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. 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) which is left to stand for 500 hours on condition of temperature 85 degreeC and humidity 85%. The case where the conduction resistance after the reliability test was <5Ω was A, the case of 5-10Ω was B, and the case of 10Ω or more was C. On the other hand, regarding the insulation resistance between the chip electrodes, an average value was obtained when 10 locations were measured. In addition, the insulation resistance measured the initial value and the value after the reliability test (migration test) left to stand for 500 hours on the conditions of 60 degreeC of air temperature, 90% of humidity, and 20V application. The insulation resistance after the reliability test was> 10 ⁹ (Ω), and A was <10 ⁹ and B.

  As shown in Table 3, the samples of Evaluation Examples 1 to 6 showed good conduction characteristics and insulation characteristics before and after the reliability test. This is considered to be because the insulating properties could be improved without deteriorating the conduction properties by selectively hydrophobizing the particle surfaces, particularly the child particle surfaces. Moreover, the yield was maintained at 100% even after the reliability test.

  In Evaluation Example 7, when the coating was cross-linked with aziridine, the aziridine compound was multifunctional, so that unreacted sites remained and inhibition of curing occurred. Further, since the solvent resistance is poor, it is presumed that aggregation is likely to occur during kneading into the resin, and the insulating properties are deteriorated.

  Although the evaluation example 8 has good insulation characteristics, since the entire surface is covered with the child particles and the base material particles, the conduction resistance is high from the initial connection stage.

  In Evaluation Example 9, since the hydrophobization treatment was not performed, it was estimated that the monodispersion rate was poor and the insulation characteristics were deteriorated.

  In Evaluation Example 10, child particles coated with a polymer shell are used, and the solvent resistance of the polymer shell is poor. Therefore, peeling from the substrate particles easily occurs during kneading with the resin, resulting in poor reliability. It is estimated that

  In Evaluation Example 11, since the alkyl chain of the amino compound is short, it is presumed that the dispersibility in the anisotropic conductive material is lowered and the insulating properties are deteriorated.

  DESCRIPTION OF SYMBOLS 1 ... Child particle | grains, 2, 2a ... Base material particle | grains, 3 ... Amino compound, 4 ... 1st board | substrate, 5 ... 1st electrode, 6 ... 2nd board | substrate, 7 ... 2nd electrode 10, 10a ... Insulating coating conductive particles (conductive particles), 11 ... spherical core particles, 12 ... metal layer, 40 ... anisotropic conductive material, 42 ... conductive connection structure.

Claims (8)

Substrate particles having a surface made of a conductive metal;
An insulating child particle covering a part of the surface of the substrate particle,
At least one of the base particle and the child particles, functional group equivalent has an amino compound chemically bonded 100~10000g / mol,
The amino compound is an aminosilicone;
Conductive particles.   The conductive particles according to claim 1, wherein the amino compound contains an alkyl chain having 6 to 18 carbon atoms. The amino compound is selectively chemically bonded in or on the child particles, the conductive particles according to claim 1 or 2. The electroconductive particle as described in any one of Claims 1-3 in which the said child particle has a carboxyl group or a glycidyl group on the surface of the said child particle. The contact angle between the surface and a water droplet layer including a plurality of said conductive particles is 125 ° or more, the conductive particle according to any one of claims 1-4. The electroconductive particle as described in any one of Claims 1-5 whose monodispersion rate in resin is 50% or more. An insulating binder resin;
An anisotropic conductive material comprising: the conductive particles according to any one of claims 1 to 6 dispersed in the binder resin. The electrically conductive connection structure electrically connected by the electrically-conductive particle as described in any one of Claims 1-6 , or the anisotropic electrically-conductive material as described in Claim 7 .

Images