JP5821552B2 - Water-repellent conductive particles, anisotropic conductive material, and conductive connection structure - Google Patents

Description

  The present invention relates to a water-repellent 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. In particular, 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 current flowing between the conductive particles. The dispersibility of the conductive particles in the film 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. Furthermore, Non-Patent Document 1 proposes a method for achieving water repellency using nanoparticles.

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

Journal of the Adhesion Society of Japan, Vol. 43, no. 12, 2007, p488-493

(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 general, it is known that water repellency or hydrophilicity is emphasized when a solid surface is uneven. Specifically, the surfaces of natural taro, lotus, and amadokoroko are covered with hydrophobic hair, and these leaves exhibit water repellency. A method for making the solid surface water-repellent using nanoparticles using such characteristics has been proposed. Non-Patent Document 1 discloses that the contact angle between the solid surface and water is improved to 150 ° or more by dispersing and coating hydrophobic nanoparticles on the solid surface.

  In view of the above, the present invention makes it possible to reliably perform conductive connection between substrates, and to prevent leakage between adjacent particles and obtain good insulating properties between adjacent electrodes. An object is to provide particles, anisotropic conductive materials using the same water-repellent conductive particles, and conductive connection structures.

  As a means for solving the above-described conventional problems, the present inventors form convex portions by adsorbing child particles to conductive base particles, and at least one of the base particles and the convex portions. It has been found that by reacting a compound having a hydrophobic group with a compound having a hydrophobic group, improvement in dispersibility in an ACF resin and prevention of short-circuiting due to a decrease in hygroscopicity of convex portions can be achieved without reducing conductivity. It was completed.

That is, the present invention comprises a base particle having a surface made of a conductive metal, and an insulating convex portion existing on the surface of the base particle, and at least one of the base particle and the convex portion is provided. The compound having a hydrophobic group is chemically bonded, the compound having the hydrophobic group is a silicone compound, the diameter of the base particle is 1.0 to 10 μm, and the unevenness ratio represented by the following formula (1) is Water-repellent conductive particles having a particle size of 0.05 to 0.17. With such water-repellent 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.
Concavity and convexity ratio = T1 / D1 (1)
[Wherein, D1 is the diameter of the base particle, and T1 is the height of the convex portion from the surface of the base particle. ]

  It is preferable that the proportion of the protrusions on the surface of the substrate particles is 20 to 50%. Thereby, high water repellency can be imparted to the conductive particles.

  The convex portion is preferably made of polymer fine particles. This facilitates the introduction of hydrophobic groups into the conductive particles, particularly the convex portions, and further suppresses conduction inhibition during low-pressure mounting.

  The compound having a hydrophobic group is preferably selectively chemically bonded to the surface of the convex portion. By selectively introducing a hydrophobic group on the surface of the convex portion, conduction inhibition of the conductive particles can be more reliably suppressed. The hydrophobic group itself of the compound having a hydrophobic group may be directly chemically bonded to the surface of the convex portion.

The compound having a hydrophobic group preferably contains an alkyl chain having 6 to 18 carbon atoms. This makes it possible to impart high water repellency to the conductive particles, and more easily suppress aggregation of the conductive particles in the ACF resin. From the same viewpoint, Ru hydrophobic group silicone compound der.

  When the convex part has a carbosyl group or an epoxy group on its surface, the compound having a hydrophobic group is preferably chemically bonded to these carboxyl group or epoxy group. In such a case, it becomes easy not only to introduce a compound having a hydrophobic group, but also to impart good water repellency to the conductive particles.

  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 water-repellent conductive particles dispersed in the binder resin. Since it is an anisotropic conductive material containing the water-repellent conductive particles of the present invention, it is possible to reliably perform conductive connection between substrates and to prevent leakage between adjacent particles.

  Furthermore, the present invention provides a conductive connection structure that is electrically connected by the water-repellent 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, the water-repellent conductive particles capable of reliably performing conductive connection between substrates and preventing good leakage between adjacent particles and obtaining good insulating properties between adjacent electrodes. An anisotropic conductive material and a conductive connection structure using water-repellent conductive particles can be provided.

FIG. 1 is a schematic cross-sectional view of water-repellent conductive particles according to an embodiment of the present invention. FIG. 2 is a schematic diagram illustrating a method for measuring the unevenness ratio of the water-repellent conductive particles according to the embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of an anisotropic conductive material including water-repellent conductive particles according to an embodiment of the present invention. 4 (a) and 4 (b) are schematic cross-sectional views for explaining a method for producing 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.

<Water repellent conductive particles>
FIG. 1 is a schematic cross-sectional view of water-repellent conductive particles according to an embodiment of the present invention. As shown in FIG. 1, the water-repellent conductive particle 10 a of this embodiment includes a base particle 2 a and an insulating convex portion 1 existing on 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. Further, the compound 3 having a hydrophobic group is selectively chemically bonded to the surface of the convex portion 1.

[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 water-repellent conductive particles of this embodiment are used as an anisotropic conductive material, the bonding area between the substrate particle surface 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 a crosslinkable monomer. Specifically, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ -Methacryloxypropylmethyldiethoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-methacryloxypropylbis (trimethoxy) methylsilane, 11-methacryloxyundecamethylenetrimethoxysilane, vinyltriethoxysilane, 4-vinyltetramethylene Trimethoxysilane, 8-vinyloctamethylenetrimethoxysilane, 3-trimethoxysilylpropyl vinyl ether, vinyltriacetoxysilane, p-trimethoxysilylstyrene, p-triethoxy Ril styrene, 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.

[Convex]
In the water-repellent conductive particles of the present embodiment, it is preferable that convex portions having a hydrophobic group on the surface are present on the surface of the substrate particles in order to impart water repellency. The material constituting the convex portion is not particularly limited as long as it has insulating properties, but it is preferable to use polymer particles in order not to impair the conductive properties of the conductive particles. Since the thermal characteristics can be adjusted by appropriately selecting the type of material constituting the convex portion, the convex portion is likely to be deformed, and the electrical conductivity is improved when crimping between the substrates. When polymer particles (polymer fine particles) are used as the convex portions, the polymer particles may be used alone or in combination of two or more. The manufacturing method of the convex part of this embodiment is not specifically limited, Well-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, can be used. Among these, it is preferable to produce the composition by a soap-free emulsion polymerization method because it is easy to control the size and is suitable 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 amount thereof, the type of functional group, the viscosity of the solution, the concentration thereof, For example, in the case of 40 to 90 ° C., it is 1 to 72 hours, preferably about 2 to 24 hours.

  The convex portion preferably has a functional group on the surface capable of reacting with a compound having a hydrophobic group. Examples of such functional groups include a carboxyl group, an epoxy group, a glycidyl group, a carboxylic acid anhydride, and an active ester group. Among these functional groups, when the reaction with the compound having a hydrophobic group is fast, the convex portions may be aggregated and formed. Therefore, it is preferable to use a carboxyl group, an epoxy group or a glycidyl group. In order to obtain convex portions 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% so that the convex portions are not aggregated and formed on the surface of the substrate 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 to the convex surface. Moreover, in order to introduce efficiently to the convex part surface, when the convex part consists of particle | grains, the method of seed-polymerizing the said monomer with respect to the particle | grains synthesize | combined beforehand is 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.

  When the convex portion is made of polymer particles, an emulsifier can be used in combination to improve the dispersibility of the polymer particles. Examples of emulsifiers that can be used in the present embodiment include anionic emulsifiers and nonionic emulsifiers. 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 convex portion can be arbitrarily adjusted by selecting a polymerizable monomer to be used, or 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 size of the protrusions is preferably 200 to 500 nm, although it varies depending on the particle diameter of the base particles and the use of the water-repellent conductive particles of the present embodiment. If it is less than 100 nm, the distance between adjacent coated conductive particles becomes smaller than the hopping distance of electrons, and leakage may easily occur. On the other hand, when the thickness exceeds 500 nm, the conduction resistance may become excessively large during mounting at a low pressure. In addition to this, when the thickness exceeds 500 nm, the physical properties of the base particles may be governed by the physical properties of the convex portions, and it becomes difficult to obtain the effect of using the base particles. More preferably, the minimum of the size of a convex part is 150 nm, and a preferable upper limit is 400 nm. The size of the convex portion can also be measured in the same manner as the particle diameter.

  In addition, when a convex part consists of particle | grains, since a small convex part (particle | grain) enters into the clearance gap covered with the large convex part (particle | grain) and can improve a coating density, it is 2 or more types of convexes from which a particle diameter differs. Parts (particles) may be used in combination. At this time, the size of the small protrusions is preferably 1/2 or less of the size of the large protrusions, and the number of small protrusions is preferably 1/4 or less of the number of protrusions.

The convex portion preferably has a CV value (variation coefficient) of the size of the convex portion of 10% or less. If it exceeds 10%, the size of the obtained water-repellent 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. Note that the CV value of the size of the convex portion can be calculated by the following formula (2).
CV value of convex size (%) = standard deviation of convex size / average value of convex size × 100 (2)
When the convex portion is a particle, the standard deviation can be measured with a particle size distribution meter or the like before being formed on the base particle, but after being formed on the base particle, it is measured by image analysis of an SEM photograph or the like. be able to.

The water-repellent conductive particles of the present embodiment have a concavo-convex ratio represented by the following formula (1) of 0.05 to 0.17, preferably 0.07 to 0.17. When the concavo-convex ratio is less than 0.05, the water repellency becomes insufficient, so that the insulating properties and the dispersibility in the resin are lowered. On the other hand, if it exceeds 0.17, it will be difficult to adsorb the convex parts to the base particles, and it will be easy to peel off.
Concavity and convexity ratio = T1 / D1 (1)
[Wherein, D1 is the diameter of the base particle, and T1 is the height of the convex portion from the surface of the base particle. ]

  FIG. 2 is a schematic diagram illustrating a method for measuring the unevenness ratio of the water-repellent conductive particles according to the embodiment of the present invention. In particular, this is a method for measuring the unevenness ratio when the substrate particles 2 are not spherical. In the measurement, first, an SEM image of the water-repellent conductive particles is subjected to image processing to obtain a projected view of the water-repellent conductive particles. Then, an inscribed circle S to the outline of the base particle 2 is drawn in the projected view, and the diameter of the inscribed circle is set to D1. On the other hand, the height of the convex portion 1 from the inscribed circle S is measured with respect to ten convex portions (T1a, T1b,...), And the average value is defined as T1. Thus, the unevenness ratio of the observed individual water-repellent conductive particles is calculated according to the above formula (1). This operation is performed on 100 water-repellent conductive particles, and the average value thereof is taken to obtain the unevenness ratio of the entire water-repellent conductive particles = T1 / D1.

In the water-repellent conductive particles of the present embodiment, the coverage defined by the following formula (3) (the ratio of the convex portion to the surface of the substrate particles) is preferably 20 to 50%. That is, it is preferable that 20 to 50% of the surface of the base particle is covered with the convex portion. The coverage is more preferably 30 to 50%. Hereinafter, the coverage may be described as a coating density. The coating density is obtained by preparing 100 SEM images of base material particles having protrusions adsorbed on the surface, and analyzing the center of the base material particles (circle having a diameter of 2 μm).
Coverage ratio (%) = {(area of the portion covered with the convex portions on the surface of the base particle) / (total surface area of the base particle)} × 100 (3)

  When the coating density is less than 20%, the metal surface of the base material particle is in contact between adjacent particles, so that lateral leakage tends to occur and insulation may not be ensured. On the other hand, if the coating density exceeds 50%, sufficient conductivity may not be ensured. In addition, the coating density by the convex part on the surface of a base particle is the addition amount (concentration) of a particle, the amount (density) of the functional group introduced into the base particle surface, and the reaction solvent when the convex part is made of particles It is possible to control depending on the type.

[Compound having a hydrophobic group]
In order to improve the dispersibility of the conductive particles in the ACF resin, the conductive particles including the base particles and the protrusions are treated with a compound having a hydrophobic group. If the hydrophobic group is introduced on the surface of the conductive particles, the dispersibility can be improved. In particular, it is preferable that the hydrophobic group is selectively introduced on the surface of the convex portion. In addition, the coupling | bonding to the convex part of an amine can be confirmed by the composition analysis based on pyrolysis GC-MASS (Gas Chromatography Mass Spectrometry), for example. The amine adsorption site on the convex portion is identified by the identification of nitrogen atoms based on SEM-EDX (Energy Dispersive X-ray Spectroscopy), and GC-MASS on the convex portion peeled from the base particle.

  The compound having a hydrophobic group preferably contains an alkyl chain having 6 to 18 carbon atoms. As such a compound, when a convex part has a carboxyl group or an epoxy group, it is preferable that it can react easily with these functional groups to form a chemical bond, and particularly an amino compound having a hydrophobic group. It is preferable. When steric hindrance is large, the compound having a hydrophobic group preferably has a primary amino group rather than a secondary amino group in terms of reactivity. The compound having a hydrophobic group preferably has a functional group equivalent of 100 to 10,000 g / mol. When the functional group equivalent exceeds 10,000 g / mol, fusion tends to occur when the water-repellent conductive particles are dried, and when it is less than 100 g / mol, the dispersibility in the ACF resin tends to be insufficient. is there. 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.

  For example, as a compound having a primary amino group and a hydrophobic group, 1-hexylamine, 1-octaneamine, 1-nonaneamine, 1-decanamine, 1-aminoundecane, 1-dodecylamine, 1-aminotridecane, 1 -Aminopentadecane, 1-aminohexadecane, 1-aminoheptadecane, 1-octadecylamine and the like can be mentioned. As the compound having a hydrophobic group, in addition to the above, a silicone compound such as aminosilicone (amino-modified silicone), a polymer having an amino group at the terminal, or the like can be used. For example, when the convex part has a carboxyl group, these compounds are preferably used in an amount of 1.2 to 3 times the carboxyl group.

  In addition, when a convex part has a carboxyl group or an epoxy group, reaction of these functional groups and the said 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 water-repellent conductive particles of this 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 present alone without aggregating among all water-repellent 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). If the water-repellent conductive particles have a monodispersion rate of 50% or more, the insulating properties can be further improved.

<Anisotropic conductive material>
FIG. 3 is a schematic cross-sectional view of an anisotropic conductive material including water-repellent conductive particles according to the present embodiment. That is, the anisotropic conductive material 40 includes the insulating binder resin 20 and the water-repellent conductive particles 10 dispersed in the binder resin. In FIG. The compound 3 having a group is omitted.

  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 liquid in which the water-repellent 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 water-repellent 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 water-repellent 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>
4 (a) and 4 (b) are schematic cross-sectional views for explaining a method for producing 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. 4A and 4B, the compound 3 having a hydrophobic group is omitted for simplification of the drawing.

  In the conductive connection structure 42, first, as shown in FIG. 4A, 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 pressurized and heated in the 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 convex part]
(Composition of convex part 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. In addition, child particle | grains here mean the convex part 1 with which the water-repellent conductive particle after completion is equipped. When the convex part 1 was observed by SEM, the size was 203 nm and the CV of the convex part size was 2.9%.
Styrene: 600 mmol
Sodium methacrylate: 6.0 mmol
Sodium styrenesulfonate: 1.5mmol
KBM-503: 3.6 mmol
Potassium peroxodisulfate: 5.4 mmol
Divinylbenzene: 12.0mmol
Water: 400g

(Composition of convex part 2)
The procedure was the same as the synthesis of the convex portion 1 except that sodium styrenesulfonate was omitted. When the convex part 2 was observed by SEM, the size was 351 nm and the CV of the convex part size was 3.5%.

(Composition of convex part 3)
Except for sodium styrenesulfonate, the procedure was the same as the synthesis of the convex portion 1 except that sodium methacrylate was changed to 4 mmol. When the convex part 3 was observed by SEM, the size was 502 nm and the CV of the convex part size was 3.0%.

(Composition of convex part 4)
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 a convex portion. When the convex part after the synthesis was observed by SEM, the size was 281 nm, and the CV of the convex part size 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 synthesized convex dispersion, and heated and stirred at 70 ° C. for 6 hours to synthesize convex part 4 coated with glycidyl groups. When the convex part 4 was observed by SEM, the size was 315 nm, and the CV of the convex part size was 3.3%.
Glycidyl methacrylate: 60mmol
Potassium peroxodisulfate: 0.06mmol

(Composition of convex part 5)
In the synthesis of the convex part 1, the synthesis was performed in the same manner as the convex part 1 except that 3 mmol of sodium styrenesulfonate was used. When the convex part 5 was observed by SEM, the size was 130 nm and the CV of the convex part size was 2.3%.

(Composition of convex part 6)
The convex part 3 was synthesized in the same manner as the convex part 3 except that the amount of sodium methacrylate was changed to 3 mmol. When the convex part 6 was observed by SEM, the size was 602 nm and the CV of the convex part size was 3.3%.

(Composition of convex part 7)
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, it was synthesized by heating and stirring at a water bath temperature of 70 ° C. for about 6 hours. When the convex part 7 was observed by SEM, the size was 320 nm and the CV of the convex part size was 3.0%. Further, after purification by centrifugation, neutralization titration of the particle dispersion was performed using KOH. As a result, the acid value of the convex portion 7 was 5 mgKOH / g.
Styrene: 600 mmol
Methacrylic acid: 6mmol
Sodium styrenesulfonate: 1.5mmol
Potassium peroxodisulfate: 5.4 mmol
Water: 400g

(Composition of convex part 8)
150 g of a 0.25 wt% sodium dodecyl sulfate aqueous solution was added to 200 g of the dispersion liquid (10 wt%) of the convex portion 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 dropping of the monomer, the reaction was further allowed to proceed for 3 hours to obtain core-shell particles (convex portion 8) having poly (ST-MMA) as a shell. Unreacted material and emulsifier were removed using a centrifuge. When the convex part 8 was observed by SEM, the size was 387 nm and the CV of the convex part size was 3.8%.

  The convex portions 1 to 8 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 2.8 μm, and a palladium layer having a thickness of 0.04 μm is further formed on the outside of the nickel to obtain 3.04 μm. Base material particles were obtained.

[Production of water-repellent conductive particles]
According to the following evaluation examples 1 to 15, water-repellent conductive particles 1 to 15 were produced.

(Evaluation example 1)
(Coating of base material particles by convex part)
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 convex portion 1 was dropped to obtain base particles whose surface was partially covered with the convex portion. The coverage of the convex portions on the surface of the substrate particles (coating density: fine particle coverage) was 35%. Hereinafter, the base particles coated with the convex portions are referred to as “convex portion-coated base particles”. The coating density was adjusted by the dropping amount of the dispersion liquid of the convex portion 1. Next, the convex covering base particles were taken out by filtration using a φ3 μm membrane filter (Millipore), and the extracted convex covering base particles were put in 200 g of ultrapure water and stirred at room temperature for 5 minutes. Thereafter, the convex-coated substrate particles are removed by filtration using a φ3 μm membrane filter (Millipore), and the convex-coated substrate particles on the membrane filter are washed twice with 200 g of ultrapure water. The convex portions not adsorbed on the particles were removed.

(Hydrophobic treatment)
While stirring 3 g of the obtained convex-coated substrate particles in 30 g of methanol, 0.2 g of DMT-MM and 0.31 g of octadecylamine which is a compound having a hydrophobic group were added, and stirring was continued for 1 hour. Thereafter, washing with methanol and filtration were repeated three times, and then the water-repellent conductive particles were vacuum-dried at 60 ° C. for 1 hour to obtain water-repellent conductive particles 1 of Evaluation Example 1. Note that octadecylamine was selectively chemically bonded to the carboxyl group of the convex portion 1.

(Measurement of unevenness ratio)
T1 and D1 were calculated by image processing of 100 photographs of water-repellent conductive particles photographed with SEM. T1 was 0.21 μm and D1 was 3.0 μm. Further, the unevenness ratio was calculated by the following formula (1).
Concavity and convexity ratio = T1 / D1 (1)
[Wherein, D1 is the diameter of the base particle, and T1 is the height of the convex portion from the surface of the base particle. ]

(Measurement of contact angle of water-repellent conductive particles)
After a double-sided tape (Nitto Denko No. 500) was applied to the slide glass, the prepared plurality of water-repellent conductive particles 1 were dispersed. Then, after removing excess water-repellent conductive particles 1, a film composed of the water-repellent 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 water-repellent conductive particles)
The obtained water-repellent conductive particles 1 are immersed in a toluene / ethyl acetate (5/5 wt%) solution, and after 5 minutes of ultrasonic irradiation (24 kHz), the water-repellent conductive particles 1 are confirmed by SEM. It was confirmed whether it was separated. The case where there was no change in the amount of adsorption of the convex portion was A, and the case where the convex portion was partially detached was designated B.

(Evaluation example 2)
A water repellent conductive particle 2 was obtained in the same manner as in Evaluation Example 1 except that the convex portion 2 was used instead of the convex portion 1. Note that octadecylamine was selectively chemically bonded to the carboxyl group of the convex portion 2.

(Evaluation example 3)
A water-repellent conductive particle 3 was obtained in the same manner as in Evaluation Example 1 except that the convex portion 3 was used instead of the convex portion 1. Note that octadecylamine was selectively chemically bonded to the carboxyl group of the convex portion 3.

(Evaluation example 4)
In Evaluation Example 2, water-repellent conductive particles 4 were obtained in the same manner except that the coating density on the surface of the water-repellent conductive particles was changed to 20% by adjusting the amount of protrusions to the base particles. Note that octadecylamine was selectively chemically bonded to the carboxyl group of the convex portion 2.

(Evaluation example 5)
In Evaluation Example 2, water-repellent conductive particles 5 were obtained in the same manner except that the covering density on the surface of the water-repellent conductive particles was changed to 50% by adjusting the amount of protrusions to the base particles. Note that octadecylamine was selectively chemically bonded to the carboxyl group of the convex portion 2.

(Evaluation example 6)
In the hydrophobizing treatment of Evaluation Example 2, water-repellent conductive particles 6 were obtained in the same manner except that equimolar amounts of dodecylamine were used instead of octadecylamine. The dodecylamine was selectively chemically bonded to the carboxyl group of the convex portion 2.

(Evaluation example 7)
Hydrophobic treatment in Evaluation Example 2 was performed in the same manner except that equimolar amount of hexylamine was used instead of octadecylamine to obtain water-repellent conductive particles 7. Hexylamine was selectively chemically bonded to the carboxyl group of the convex portion 2.

(Evaluation example 8)
Hydrophobic conductive particles 8 were obtained in the same manner as in the hydrophobic treatment of Evaluation Example 2, except that amino-modified silicone (TSF4700: Momentive) was used in an equivalent amount of amino equivalent to octadecylamine instead of octadecylamine.

(Evaluation example 9)
In evaluation example 1, water-repellent conductive particles 9 were obtained in the same manner except that the convex portion 4 was used instead of the convex portion 1. Note that octadecylamine was selectively chemically bonded to the epoxy group of the convex portion 4.

(Evaluation example 10)
In Evaluation Example 1, water-repellent conductive particles 10 were obtained in the same manner except that the convex portion 5 was used instead of the convex portion 1.

(Evaluation example 11)
In Evaluation Example 1, water-repellent conductive particles 11 were obtained in the same manner except that the convex portion 6 was used instead of the convex portion 1.

(Evaluation example 12)
In Evaluation Example 1, the projecting portion 7 was used in place of the projecting portion 1, and the projecting portion was formed on the conductive particles as follows, and the hydrophobic treatment was performed in the same manner. 12 was obtained.
(Projection formation on conductive particles)
A 0.2 μm film was formed on the conductive particles by hybridization using the convex portions 7 to obtain convex-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 on the convex-coated conductive particles obtained above. A cross-linking reaction was performed by heating and drying at 100 ° C. to obtain water-repellent conductive particles.

(Evaluation example 13)
In Evaluation Example 1, water-repellent conductive particles 13 were obtained in the same manner except that the convex portion 8 was used instead of the convex portion 1.

(Evaluation Example 14)
In Evaluation Example 2, water-repellent conductive particles 14 were obtained in the same manner except that the convex portion was not hydrophobized.

  The water repellent conductive particles 1 to 14 of Evaluation Examples 1 to 14 are collectively shown in Table 2 below.

[Production of anisotropic conductive material]
Next, using the water-repellent conductive particles 1 to 14 alone, the anisotropic conductive materials 1 to 14 were produced according to the following procedure.

  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 water-repellent 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 obtained anisotropic conductive materials 1-14 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 (4), 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 (4)
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 water-repellent 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. The film rolled using a Keyence optical microscope (VH-Z450) was imaged at 20 locations at a magnification of 1000 times, and this was image-processed to aggregate the total number of water-repellent conductive particles in the photograph. The ratio (monodispersity) of the water-repellent conductive particles present alone was evaluated. 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, each of the produced film-like anisotropic conductive materials 1 to 14 was used alone, and the conductive connection structures 1 to 14 were produced according to the following procedure.

  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 the conduction resistance test of the mounting samples (conductive connection structures 1 to 14) 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 9 showed good conduction characteristics and insulation characteristics before and after the reliability test. This is presumably because the insulating characteristics could be improved without deteriorating the conduction characteristics by selectively hydrophobizing the particle surface, particularly the convex surface.

  In Evaluation Example 10, since the size of the convex portion is small and the concave / convex ratio is small, it is estimated that good insulating properties could not be maintained. In Evaluation Example 11, since the size of the protrusions is large and the unevenness ratio is large, the insulation is good, but it is presumed that the conduction characteristics are deteriorated. When the coating was crosslinked with aziridine of Evaluation Example 12, since the aziridine compound was polyfunctional, unreacted sites remained and curing inhibition 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.

  In the evaluation example 13, the convex portion covered with the polymer shell is used, and the solvent resistance of the polymer shell is poor. Therefore, the detachment from the base material particles tends to occur at the time of kneading with the resin and the reliability is poor. It is estimated that

  In Evaluation Example 14, since the hydrophobization treatment was not performed, it was estimated that the monodispersion rate was poor and the insulation characteristics were deteriorated.

DESCRIPTION OF SYMBOLS 1 ... Child particle, 2, 2a ... Base particle, 3 ... Compound which has hydrophobic group, 4 ... 1st board | substrate, 5 ... 1st electrode, 6 ... 2nd board | substrate, 7 ... 2nd electrode, 10 , 10a ... water-repellent conductive particles, 11 ... spherical core particles, 12 ... metal layer, 40 ... anisotropic conductive material, 42 ... conductive connection structure.

Claims (9)

Substrate particles having a surface made of a conductive metal;
An insulating convex portion present on the surface of the substrate particle,
At least one of the base particle and the convex part is chemically bonded to a compound having a hydrophobic group,
The compound having a hydrophobic group is a silicone compound;
The diameter of the base particle is 1.0 to 10 μm,
Water-repellent conductive particles having an unevenness ratio represented by the following formula (1) of 0.05 to 0.17.
Concavity and convexity ratio = T1 / D1 (1)
[Wherein, D1 is the diameter of the base particle, and T1 is the height of the convex portion from the surface of the base particle. ]   The water-repellent conductive particles according to claim 1, wherein a ratio of the convex portions to the surface of the base particles is 20 to 50%.   The water-repellent conductive particles according to claim 1, wherein the convex portions are made of polymer fine particles.   The water-repellent conductive particles according to any one of claims 1 to 3, wherein the compound having a hydrophobic group is selectively chemically bonded to the surface of the convex portion.   The water repellent conductive particles according to any one of claims 1 to 4, wherein the compound having a hydrophobic group contains an alkyl chain having 6 to 18 carbon atoms. The water-repellent conductive particles according to any one of claims 1 to 5 , wherein the compound having a hydrophobic group is chemically bonded to a carboxyl group or an epoxy group on the surface of the convex portion. The water-repellent conductive particles according to any one of claims 1 to 6 , wherein the monodispersion rate in the resin is 50% or more. An insulating binder resin;
The water-repellent conductive particles according to any one of claims 1 to 7 dispersed in the binder resin.
Anisotropic conductive material. Anisotropic conductive are electrically connected by the material, a conductive connection structure according to the water-repellent conductive particles or claim 8 as claimed in any one of claims 1-7.

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