JP5939063B2 - Insulating coated conductive particles and anisotropic conductive adhesive using the same - Google Patents

Description

  The present invention relates to insulating coated conductive particles and an anisotropic conductive adhesive using the same.

  Conventionally, when electrically connecting circuit boards or IC chips or electronic components and a circuit board, an insulating adhesive, an anisotropic conductive adhesive in which conductive particles are dispersed, or the like is used. Such a connection form is remarkable in the liquid crystal field. The method of mounting the liquid crystal driving IC on the glass panel for liquid crystal display can be broadly classified into two types: COG (Chip-on-Glass) mounting and COF (Chip-on-Flex) mounting. In COG mounting, an IC for liquid crystal is directly bonded onto a glass panel using an anisotropic conductive adhesive 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 adhesive containing conductive particles. Anisotropy here means conducting in the pressurizing direction and maintaining insulation in the non-pressurizing direction. As the conductive particles, particles obtained by applying nickel plating to the outside of the plastic particles, particles obtained by plating nickel and gold or palladium in this order, or the like is used.

By the way, with recent high definition of liquid crystal display, metal bumps, which are circuit electrodes of liquid crystal driving ICs, are narrowed in pitch and area, so that the circuit where adjacent conductive particles of anisotropic conductive adhesive are adjacent. There is a risk of causing a short circuit by flowing out between the electrodes. This tendency is particularly remarkable in COG mounting. When conductive particles flow out between adjacent circuit electrodes, the number of conductive particles in the anisotropic conductive adhesive captured between the metal bumps and the glass panel decreases, and the connection resistance between the opposing circuit electrodes increases. There is a risk of poor connection. Such a tendency becomes more remarkable when 20,000 particles / mm ² or more of conductive particles are introduced per unit area.

  Therefore, as a method for solving these problems, a method has been proposed in which a plurality of insulating particles (child particles) are attached to the surface of conductive particles (mother particles) to form composite particles. For example, Patent Document 1 and Patent Document 2 propose a method of attaching spherical resin particles to the surface of conductive particles. Patent Document 1 also discloses a method of deforming insulating particles. In Patent Document 3 and Patent Document 4, insulating coated conductive particles in which core-shell type resin particles are attached to the surface of the conductive particles are used. In Patent Document 5, composite particles in which hollow resin fine particles are attached to the surface of the conductive particles. , Each has been proposed.

Japanese Patent No. 4777385 Japanese Patent No. 3869785 Japanese Patent No. 4686120 Japanese Patent No. 4904353 Japanese Patent No. 4391836

By the way, in connection of a minute circuit having a bump area of less than 3,000 μm ² , it is preferable to increase the number of conductive particles in order to obtain stable conduction reliability. However, in the connection of such a minute circuit, it is difficult to balance the conduction reliability and the insulation reliability even if the conventional insulating coating conductive particles described in Patent Documents 1 to 5 are used, and yet There is room for improvement.

  The present invention has been made in view of the above-described problems of the prior art, and includes insulating coated conductive particles that are excellent in both insulation reliability and conduction reliability even in connection of a minute circuit, and the insulating coated conductive particles. An object is to provide an anisotropic conductive adhesive used.

  The present invention is an insulating coated conductive particle comprising conductive particles and a plurality of insulating particles attached to the outside of the conductive particles, wherein the conductive particles have an average particle size of 1 to 10 μm, and the insulating particles Relates to insulating coated conductive particles including first insulating particles and second insulating particles having a glass transition temperature lower than that of the first insulating particles.

  In the insulating coated conductive particles, the first insulating particles function as an insulating spacer, and the second insulating particles are thought to further improve the insulation reliability without substantially impeding the conduction reliability. Therefore, according to the insulating coated conductive particles of the present invention, it is possible to achieve both excellent conduction reliability and insulation reliability by having the above configuration.

  The coverage of the conductive particles by the first insulating particles and the second insulating particles is preferably 35 to 75% with respect to the total surface area of the conductive particles. Thereby, the insulation coating electroconductive particle which is excellent by conduction | electrical_connection reliability and insulation reliability is obtained.

  The average particle diameter of the first insulating particles is preferably larger than the average particle diameter of the second insulating particles. As a result, the second insulating particles can adhere to the gaps not covered with the first insulating particles to cover the conductive particles, and the insulation reliability of the insulating coated conductive particles can be greatly improved. it can.

  Preferably, the average particle diameter of the first insulating particles is larger than 200 nm and not larger than 500 nm. Thereby, it is easy to coat the first insulating particles on the conductive particles, and the insulation reliability of the insulating coated conductive particles can be further improved.

  The average particle size of the second insulating particles is preferably 50 to 200 nm. The second insulating particles having such an average particle diameter are easy to synthesize and can further improve the coverage and insulating reliability of the insulating coated conductive particles.

  The glass transition temperature (Tg) of the second insulating particles is preferably 10 ° C. or lower than the Tg of the first insulating particles. Since the difference in Tg between the first insulating particles and the second insulating particles is 10 ° C. or more, the first conductive particle is heated by the heating pressure when the anisotropic conductive adhesive is used for circuit connection. The insulating particles are not completely melted and can sufficiently function as an insulating spacer.

  The Tg of the second insulating particles is preferably 80 to 120 ° C. Thereby, the second insulating particles are easily melted, and the insulation reliability can be improved without impairing the conduction reliability.

  The Tg of the first insulating particles is preferably 100 to 150 ° C. As a result, the first insulating particles are not completely melted by the heating temperature when heating and pressurizing when the anisotropic conductive adhesive containing the insulating coating conductive particles is used for circuit connection, and the insulating spacer is used as an insulating spacer. It can function well.

  The present invention also relates to an anisotropic conductive adhesive containing the insulating coated conductive particles. Such an anisotropic conductive adhesive is excellent in both insulation reliability and conduction reliability.

  The anisotropic conductive adhesive is interposed between a first circuit member having a first connection terminal and a second circuit member having a second connection terminal, and is heated and pressurized to thereby form a first circuit member. An anisotropic conductive adhesive for electrically connecting the connection terminal and the second connection terminal, and the heating temperature in the heating and pressurization is 30 ° C. or more higher than the glass transition temperature of the second insulating particles It is preferable. Thereby, when the anisotropic conductive adhesive is heated and pressurized, the second insulating particles are easily dissolved, and the insulation reliability can be improved without impairing the conduction reliability.

  The heating temperature in the heating and pressurization is preferably higher than the glass transition temperature of the first insulating particles. Thereby, conduction reliability can be improved.

  According to the present invention, there are provided insulating coated conductive particles that are excellent in both insulation reliability and conduction reliability even in connection of a minute circuit, and an anisotropic conductive adhesive using the insulating coated conductive particles. Can do.

It is a schematic cross section showing one embodiment of insulating covering conductive particles. A plurality of at least two types of insulating particles having different Tg are attached to the outside of the conductive particles. It is sectional drawing which shows one Embodiment of the circuit connection method by anisotropically conductive adhesive. It is sectional drawing which shows one Embodiment of a circuit connection structure.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. However, the present invention is not limited to the following embodiments. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

  FIG. 1 is a schematic cross-sectional view showing an embodiment of insulating coated conductive particles. The insulating coated conductive particles 4 according to the present embodiment include conductive particles 12 and a plurality of insulating particles 13 attached to the outside of the conductive particles. The conductive particles 12 have a plastic core 10 and a metal coating 11 that covers the plastic core. The insulating particles 13 include first insulating particles 13 a and second insulating particles 13 b and cover a part of the surface of the conductive particles 12.

  The average particle diameter of the conductive particles 12 used in the present embodiment is 1 to 10 μm, preferably 2 to 5 μm, and more preferably 2 to 3 μm. When the average particle diameter of the conductive particles 12 is 1 μm or more, variations in the height of the electrodes can be absorbed, and conduction reliability can be improved. Moreover, it is excellent in insulation reliability as the average particle diameter of the electrically-conductive particle 12 is 10 micrometers or less.

  The average particle diameter of the conductive particles 12 described here is obtained by photographing about 100 conductive particles at a magnification of several thousand to several tens of thousands times with an electron microscope (SEM), measuring the particle diameter by image analysis, and calculating the average. Assume that you have asked for it. The particle diameter in this example was measured by HITACHI S-4800 (manufactured by Hitachi High-Tech Co., Ltd., trade name). The average particle diameter of the conductive particles 12 can also be determined by measuring the average particle diameter of the plastic core 10 by the same method as described above, and then measuring the thickness of the metal coating 11 and adding them up. The thickness of the metal coating 11 can be measured by a general method such as atomic absorption spectrophotometer and SEM cross-sectional observation.

  The conductive particles may be particles made of only metal, or may be one in which a metal conductive film is coated on an organic or inorganic core by a method such as plating. From the standpoint that the variation in the particle diameter of the conductive particles can be reduced, it is preferable that the plastic core is metal-coated. The method for coating the plastic core 10 with the metal coating 11 is not particularly limited, and examples thereof include a sputtering method and a plating method. Among these, the plating method is preferable from the viewpoint of simplicity.

  Although it does not specifically limit as a metal coat | covered with plating etc., For example, metals, such as gold | metal | money, silver, copper, platinum, zinc, iron, palladium, nickel, tin, chromium, titanium, aluminum, cobalt, germanium, and cadmium, and Examples thereof include metal compounds such as ITO and solder. From the viewpoint of corrosion resistance, the metal to be coated is preferably one or more metals selected from the group consisting of nickel, palladium and gold. In order to improve conduction reliability and hardness, carbon compounds such as carbon nanotubes and carbon black can be mixed with the metal.

  The metal coating 11 may have a single layer structure or a laminated structure composed of a plurality of layers. In the case of a single layer structure, the plating layer is preferably nickel from the viewpoints of cost, conduction reliability, and corrosion resistance. Furthermore, considering the recent flattening of glass electrodes, nickel plating having protrusions on the surface is preferable in order to improve conduction reliability. Moreover, when it is a multilayer structure, what has a noble metal like gold | metal | money or palladium on the outer side of nickel from viewpoints, such as conduction | electrical_connection reliability, is preferable.

  Examples of the method for forming protrusions on the metal coating 11 include a method using abnormal deposition of plating and a method using a core material. However, in consideration of making the protrusion shape uniform, a method using a core material is preferable. Examples of the core material include conductive materials such as nickel, carbon, palladium, and gold, and non-conductive materials such as plastic, silica, and titanium oxide. When a ferromagnetic material is used for the core material, magnetic aggregation increases at the stage of covering the insulating particles, and it becomes difficult to attach the insulating particles 13. For example, when nickel, which is a ferromagnetic material, is used as the core material, The core material preferably further contains a nonmagnetic material such as phosphorus.

  The size of the protrusion is preferably 30 to 300 nm, and more preferably 50 to 200 nm. When the size of the protrusion is 300 nm or less, the probability of short circuit is reduced, and when the size is 30 nm or more, more excellent conduction reliability is obtained. The coverage of the protrusions is desirably 5 to 60% with respect to the total surface area of the conductive particles 12. Further, the size of the protrusion is not included in the average particle diameter of the conductive particles 12. Note that the coverage of the protrusion can be obtained by image analysis of the SEM image.

  Although the thickness of the metal coating 11 is not specifically limited, 0.001-1.0 micrometer is preferable and 0.005-0.3 micrometer is more preferable.

  When the thickness of the metal coating 11 is 0.001 μm or more, poor conduction can be prevented to a higher degree, and when it is 1 μm or less, the conduction reliability is excellent.

  The material of the plastic core 10 is not particularly limited, and examples thereof include acrylic resins such as polymethyl methacrylate and polymethyl acrylate, polyolefin resins such as polyethylene, polypropylene, polyisobutylene, and polybutadiene, and copolymers of olefin and acrylic acid. . From the viewpoint of conduction reliability, the plastic core 10 is preferably a copolymer of olefin and acrylic acid, and more preferably a copolymer of divinylbenzene and acrylic acid.

  As the insulating particles 13 covering the conductive particles 12, two types of resin particles having different characteristics are used. That is, the insulating particles 13 include first insulating particles 13a and second insulating particles 13b having a Tg lower than that of the first insulating particles 13a.

  The Tg of the second insulating particles 13b is preferably 5 ° C. or more lower than the Tg of the first insulating particles 13a, more preferably 10 ° C. or more. As a result, the first insulating particles are not completely melted by the heating temperature when heating and pressurizing when the anisotropic conductive adhesive using the insulating coated conductive particles 4 is used for circuit connection. Insulating coated conductive particles 4 are obtained in which the particles are sufficiently melted and both conduction reliability and insulation reliability are excellent. The upper limit of the difference between the Tg of the second insulating particles 13b and the Tg of the first insulating particles 13a is not particularly limited, but can be, for example, 50 ° C. or less.

  In addition, since the heating temperature in the case of using an anisotropically conductive adhesive for circuit connection is generally 120 to 220 ° C, the Tg of the first insulating particles 13a as described above is 100 to 150 ° C. It is desirable.

  The second insulating particles 13b should be easily melted so as not to substantially impair conduction reliability, and Tg is preferably 80 to 120 ° C, more preferably 90 to 120 ° C. When the Tg is 80 ° C. or higher, the insulating particles are not completely melted during thermocompression bonding, and the insulation reliability is improved. When Tg is 120 ° C. or lower, the insulating particles are sufficiently melted, and excellent conduction reliability can be maintained.

  The Tg of the second insulating particle 13b is preferably lower by 30 ° C. or more than the heating temperature when heating and pressurizing when used for the circuit connection of the anisotropic conductive adhesive. When the difference between the Tg of the second insulating particles 13b and the heating temperature when heating and pressurizing when used for circuit connection is 30 ° C. or more, sufficient melting of the insulating particles can be obtained.

  It is desirable that the average particle size of the first insulating particles 13a is larger than the average particle size of the second insulating particles 13b. Preferably, the average particle diameter of the second insulating particles 13b is 1/10 to 1 / 1.5 of the average particle diameter of the first insulating particles 13a, and more preferably 1/5 to 1/1. 5, more preferably 1/4 to 1/2. Thereby, the second insulating particles can adhere to the gaps not covered with the first insulating particles and cover the conductive particles.

  The average particle diameter of the first insulating particles 13a is preferably larger than 200 nm and not larger than 500 nm. When the average particle size of the first insulating particles 13a is larger than 200 nm, the first insulating particles 13a sufficiently function as an insulating spacer, and better insulating reliability can be obtained. Further, when the average particle size is 500 nm or less, the insulating particles can be more easily coated on the conductive particles 12.

  The second insulating particles 13b not only function as the final insulating safety device, but also increase the dispersibility of the insulating coated conductive particles 4 in the resin. The average particle size of the second insulating particles 13b is preferably 50 to 200 nm. When the average particle size is 50 nm or more, not only the synthesis of the insulating particles becomes easy, but also it can sufficiently function as an insulating spacer. When the average particle size is 200 nm or less, the conduction is not substantially inhibited, and the conductive particles are coated by adhering better to the gaps not covered with the first insulating particles. The coverage of the conductive particles by the second insulating particles (hereinafter also referred to as the total coverage) can be improved, and sufficient insulation reliability can be obtained.

  The variation in the particle size of the insulating particles 13 (hereinafter also referred to as CV) is preferably 10% or less, and more preferably 3% or less. When CV is 10% or less, conduction reliability and insulation reliability can be improved.

  When the conductive particles 12 have protrusions, the average particle diameter of the insulating particles 13 is desirably larger than the protrusions from the viewpoint of easily attaching the insulating particles 13 to the conductive particles 12.

  The shape of the insulating particles 13 is not particularly limited, and may be spherical or non-spherical. Non-spherical shapes are, for example, flat, red blood cell, and semicircular. In addition, the erythrocyte shape may have a dent only on one side (bowl type) or may be on both sides.

  Examples of the insulating particles coated on the conductive particles include particles containing a polyolefin resin such as polyethylene, polypropylene, and polybutadiene, an acrylic resin such as polymethyl methacrylate, an epoxy resin, a polystyrene resin, and a polyimide resin.

  Among these, from the viewpoint of more easily controlling Tg, crosslinked plastic fine particles in which methyl acrylate having a Tg of around 100 ° C. and styrene are copolymerized with a crosslinking component are preferable.

  In addition, from the viewpoint of achieving both flexibility and solvent resistance, organic-inorganic hybrid particles such as a copolymer of silicon-containing monomer and acrylic can also be used as insulating particles.

  As a method for producing the insulating particles 13, soap-free emulsion polymerization is preferred.

  Insulating particles 13 are preferably a copolymer using a monomer composition containing an alkoxysilane having a carbon-carbon double bond in order to improve reliability. Examples of the alkoxysilane include 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxy. Silane etc. are mentioned. Of these, 3-methacryloxypropyltrimethoxysilane is preferably used.

  The content of the alkoxysilane having a carbon-carbon double bond is preferably 0.5 to 5 mol% with respect to the total amount of the monomer composition.

  Examples of the radical polymerization initiator include benzoyl peroxide, t-butylbenzoate, potassium peroxodisulfate, 1,1-azobis (cyclohexane-1-carbonitrile), 2,2-azobisisobutyronitrile and the like. However, it is not limited to these.

  When soap-free emulsion polymerization is performed, by adding a hydrophilic monomer, the particles can be synthesized more stably and the control of the particle size becomes easier. Specific examples of the hydrophilic monomer include sodium styrene sulfonate, methacrylic acid, and sodium methacrylate.

  It is preferable that content of a hydrophilic monomer is 0.1-30 mol% with respect to the monomer composition whole quantity.

  The Tg of the insulating particles 13 can be adjusted by adding a concentration of a crosslinking material or a component such as an alkyl acrylate. Addition of a cross-linking material tends to increase Tg, and conversely, Tg can be decreased by increasing the ratio of low Tg components such as alkyl acrylate.

  In addition to increasing Tg, the crosslinking agent also improves the solvent resistance and heat resistance of the insulating particles. Specifically, divinylbenzene and diacrylate are preferable as the crosslinking agent. Moreover, it is preferable that content of a crosslinking agent is 0-10 mol% with respect to all the monomers of the insulating particle 13 from a viewpoint of the easiness of a synthesis | combination, and also when a characteristic is considered, content of a crosslinking agent is 1. More preferably, it is -5 mol%.

Soap-free emulsion polymerization methods are well known to those skilled in the art. Preferably, for example, a monomer for synthesis, water, and a polymerization initiator are placed in a flask, and stirring is performed at a stirring speed of 100 to 500 min ⁻¹ (100 to 500 rpm) in a nitrogen atmosphere. The total monomer content is desirably 1 to 20% by mass with respect to the solvent water.

  The polymerization temperature of soap-free emulsion polymerization is preferably 40 to 90 ° C., and the polymerization time is preferably in the range of 2 hours to 15 hours. Appropriate polymerization temperature and time can be appropriately selected by those skilled in the art.

  A method of attaching the insulating particles 13 to the conductive particles 12 is not particularly limited, and examples thereof include a method of attaching the insulating particles 13 with functional groups to the conductive particles 12 with functional groups. Therefore, it is desirable that the insulating particles 13 have a functional group with good reactivity such as a hydroxyl group, a silanol group, and a carboxyl group on the outside.

  It is preferable that functional groups such as a hydroxyl group, a carboxyl group, an alkoxy group, and an alkoxycarbonyl group are formed on the surface of the conductive particle 12. When the conductive particles 12 have these functional groups on the surface, a strong bond such as a covalent bond or a hydrogen bond by dehydration condensation can be formed with the functional group on the surface of the insulating particle 13.

  When the conductive particles 12 have a gold or palladium surface, a hydroxyl group, a carboxyl group, or a carboxyl group is formed on the surface of the metal layer using a compound having any of a mercapto group, a sulfide group, and a disulfide group that forms a coordinate bond with gold or palladium. One or more functional groups selected from the group consisting of an alkoxyl group and an alkoxycarbonyl group may be introduced. Specifically, mercaptoacetic acid, 2-mercaptoethanol, methyl mercaptoacetate, mercaptosuccinic acid, thioglycerin, cysteine and the like are used.

  When the conductive particles 12 have a nickel surface, a compound having a silanol group or a hydroxyl group that forms a strong bond to nickel, or a group consisting of a nitrogen compound, a hydroxyl group, a carboxyl group, an alkoxyl group, and an alkoxycarbonyl group on the nickel surface. One or more functional groups selected may be introduced. Specifically, carboxybenzotriazole or the like is used.

  The method for treating the surface of the metal layer with the above compound is not particularly limited, but a compound such as mercaptoacetic acid or carboxybenzotriazole is dispersed at a concentration of 10 to 100 mmol / L in an organic solvent such as methanol or ethanol, There is a method of dispersing conductive particles having a metal layer surface.

  However, the surface potential (zeta potential) of the conductive particles 12 having a hydroxyl group, a carboxyl group, an alkoxyl group, or an alkoxycarbonyl group is usually negative when the pH is in a neutral region. On the other hand, the surface potential of the insulating particles 13 having a hydroxyl group is usually negative. In many cases, it is difficult to sufficiently cover the surface of particles having a negative surface potential with particles having a negative surface potential. However, by providing a polymer electrolyte layer between them, the insulating particles 13 can be efficiently conducted. It can be attached to the particles 12.

  Further, by providing the polymer electrolyte layer, the surface of the conductive particles 12 can be uniformly coated with the insulating particles 13 without any defects. Thereby, insulation reliability is ensured even when the circuit electrode interval is narrow, while the connection resistance is low between the electrically connected electrodes, and the conduction reliability is good.

A method for attaching the insulating particles 13 having a functional group to the outside of the conductive particles 12 having a functional group via a polymer electrolyte is not particularly limited, but a method of alternately laminating the polymer electrolyte and the insulating particles 13 may be used. preferable. As a more specific manufacturing method,
(1) Dispersing the conductive particles 12 having a functional group in a solution containing a polymer electrolyte, adsorbing the polymer electrolyte on at least a part of the surface of the conductive particles 12 having a functional group, and rinsing;
(2) Conductive particles 12 on which polymer electrolyte is adsorbed are dispersed in a solution containing insulating particles 13, and insulating particles are applied to at least part of the surface of conductive particles 12 having functional groups adsorbed on polymer electrolyte. Attaching and rinsing, and
including. By the above method, the insulating coated conductive particles 4 having the polymer electrolyte and the insulating particles 13 laminated on the surface can be manufactured.

  Such a method is called an alternating lamination method (Layer-by-Layer assembly). The alternate lamination method is described in G.H. This is a method for forming an organic thin film published in 1992 by Decher et al. (Thin Solid Films, 210/211, p831 (1992)). In this method, the substrate is alternately immersed in an aqueous solution containing a polymer electrolyte having a positive charge (polycation) and a polymer electrolyte having a negative charge (polyanion). As a result, a combination of polycation and polyanion adsorbed by electrostatic attraction on the substrate is laminated to obtain a composite film (alternate laminated film).

  In the alternate lamination method, a film grows by attracting a charge of a material formed on a substrate and a material having an opposite charge in a solution by electrostatic attraction. When the adsorption proceeds and the charge is neutralized, no further adsorption occurs. Accordingly, when reaching a certain saturation point, the film thickness does not increase any more. Lvov et al. Applied an alternate lamination method to fine particles, and reported a method of laminating a polymer electrolyte having a charge opposite to the surface charge of the fine particles by using the fine particle dispersions of silica, titania and ceria. (Langmuir, Vol. 13, (1997) p6195-6203). When this method is used, insulating particles having negative surface charges and polydiallyldimethylammonium chloride (PDDA) or polyethyleneimine (PEI), which are polycations having opposite charges, are alternately laminated to form insulating particles. It is possible to form a fine-particle laminated thin film in which and a polymer electrolyte are alternately laminated.

  After immersing the conductive particles 12 having a functional group in a solution containing a polymer electrolyte, and before immersing the conductive particles 12 in a dispersion containing the insulating particles 13, the solution containing an excess polymer electrolyte may be washed away by rinsing with a solvent alone. preferable. Moreover, it is preferable to wash away the dispersion liquid containing the excess insulating particles 13 by rinsing with only the solution after the conductive particles 12 having adsorbed the polymer electrolyte are immersed in the dispersion liquid containing the insulating particles 13.

  Examples of the solution used for such rinsing include, but are not limited to, water, alcohol, acetone, and a mixed solvent thereof.

  The polymer electrolyte is capable of adsorbing the functional group introduced on the surface of the conductive particles 12. This polymer electrolyte is, for example, electrostatically adsorbed to the functional group. As such a polymer electrolyte, a polymer (polyanion or polycation) ionized in an aqueous solution and having a charged functional group in the main chain or side chain can be used. Examples of the polyanion generally include those having a negatively charged functional group such as sulfonic acid, sulfuric acid, and carboxylic acid, but the surface potential of the conductive particles 12 and / or the insulating particles 13 is negative. It is preferable to use a polycation. The polycation generally has a positively charged functional group such as polyamines such as PEI, polyallylamine hydrochloride (PAH), PDDA, polyvinyl pyridine (PVP), polylysine, polyacrylamide. And a copolymer containing at least one of them can be used. Among these, PEI is preferably used because of its high electrification density and strong bonding strength.

  Among these polymer electrolytes, alkali metal (Li, Na, K, Rb, Cs) ions, alkaline earth metal (Ca, Sr, Ba, Ra) ions and halide ions are used to avoid electromigration and corrosion. What does not substantially contain (fluorine ion, chloride ion, bromine ion, iodine ion) is preferable.

  Any of these polymer electrolytes is water-soluble or soluble in an organic solvent such as alcohol. The weight average molecular weight of the polymer electrolyte cannot be determined unconditionally depending on the type of the polymer electrolyte to be used, but is generally preferably 1,000 to 200,000, more preferably 10,000 to 200,000. More preferably, 20,000 to 100,000 are even more preferable. When the weight average molecular weight of the polymer electrolyte is 1,000 to 200,000, sufficient dispersibility of the conductive particles 12 can be obtained, and even if the average particle size of the conductive particles 12 is 3 μm or less, the conductive particles 12 Aggregation can be prevented.

  The polymer electrolyte solution is dissolved in water or a mixed medium of an organic solvent. Examples of water-soluble organic solvents that can be used include methanol, ethanol, propanol, acetone, dimethylformamide, acetonitrile, and the like.

  In general, the concentration of the polymer electrolyte in the solution is preferably 0.01 to 10% by mass, more preferably 0.03 to 3% by mass, and 0.1 to 1% by mass. More preferably. Adhesiveness can be improved as the density | concentration of a polymer electrolyte is 0.01 mass%-10%. Further, the pH of the polymer electrolyte solution is not particularly limited.

  Further, the coverage of the conductive particles 12 with the insulating particles 13 can be controlled by adjusting the type, weight average molecular weight or concentration of the polymer electrolyte.

  Specifically, when a polymer electrolyte with a high charge density such as PEI is used, the coverage by the insulating particles 13 tends to be high, and when a polymer electrolyte with a low charge density such as PDDA is used, it depends on the insulating particles 13. The coverage tends to be low. Further, when the weight average molecular weight of the polymer electrolyte is large, the coverage by the insulating particles 13 tends to be high, and when the weight average molecular weight of the polymer electrolyte is small, the coverage by the insulating particles 13 tends to be low. Furthermore, when the polymer electrolyte is used at a high concentration, the coverage by the insulating particles 13 tends to be high, and when the polymer electrolyte is used at a low concentration, the coverage of the insulating particles tends to be low. The type, weight average molecular weight and concentration of such a polymer electrolyte can be appropriately selected by those skilled in the art.

  As the particle size of the conductive particles 12 decreases, the magnetic aggregation increases and it becomes difficult to attach the insulating particles. In that case, when the surface of the conductive particles 12 preferably has a polymer having a weight average molecular weight of 1,000 or more, dispersion of the conductive particles 12 is promoted and adhesion becomes easy.

  The insulating particles 13 also desirably have a polymer or oligomer having a weight average molecular weight of 500 to 10,000, more preferably 1,000 to 4,000 on the surface. Such a polymer or oligomer is preferably a silicone oligomer having a functional group having a weight average molecular weight of 1,000 to 4,000. The functional group is preferably one that reacts with the polymer electrolyte, more preferably a glycidyl group, a carboxyl group, or an isocyanate group, and particularly preferably a glycidyl group. Thereby, while making the dispersibility of the insulating particle 13 better, a stronger bond can be expected by reacting the functional group on the polymer or oligomer with the functional group on the conductive particle 12.

  Thus, by combining particles having a chemically reactive polymer, a strong bond that has never been obtained can be obtained. In particular, it is possible to cope with a reduction in the diameter of the conductive particles 12 and an increase in the diameter of the insulating particles 13.

  The coverage of the first insulating particles 13 a is preferably 20 to 50% with respect to the total surface area of the conductive particles 12. When the coverage of the first insulating particles 13a is 20% or more, better insulation reliability can be obtained. On the other hand, if the coverage is 50% or less, more excellent conduction reliability can be obtained. The coverage is to analyze the central part of the conductive particles 12 in the SEM photograph of the insulating coated conductive particles (a circle having a length that is half the diameter of the outer peripheral circle of the conductive particles 12 and concentric with the outer peripheral circle). It can be calculated by Specifically, the total surface area of the central part of the conductive particle 12 in the SEM photograph is W (area calculated from the particle diameter of the conductive particle), and the insulating particle 13 covers the central part of the conductive particle 12 in the SEM photograph. The coverage is expressed as P / W × 100 (%), where P is the surface area of the portion analyzed as being. In addition, the surface area P of the portion analyzed to be covered in the present embodiment is an average value of the surface areas obtained from 200 SEM photographs of the insulating coated conductive particles.

  Better insulation reliability can be obtained by covering the surface of the conductive particles not covered with the first insulating particles 13a with the second insulating particles 13b. The coverage of the conductive particles by the first insulating particles 13a and the second insulating particles 13b is preferably 35 to 75%, more preferably 40 to 75% with respect to the total surface area of the conductive particles, More preferably, it is 50 to 75%, and most preferably 60 to 75%. When the coverage is 35% or more, the insulation reliability can be improved. On the other hand, when the coverage is 75% or less, the conductive particles can be efficiently coated with insulating particles.

  In general, the insulation coated conductive particles tend to have high insulation reliability and poor conduction reliability when the insulation particle coverage is high, and high conduction reliability and insulation when the insulation particle coverage is low. There is a tendency for reliability to deteriorate. However, when two types of insulating particles having different Tg of this embodiment are used, good conductive reliability is maintained even if the coverage is increased, and insulating coated conductive particles having both excellent insulation reliability and conductive reliability are obtained. be able to.

  Further, from the viewpoint of easily controlling the amount of lamination, it is preferable that only one layer of the insulating particles 13 is coated.

  The insulating coated conductive particles 4 can further strengthen the bond between the insulating particles 13 and the conductive particles 12 by heating and drying. The reason why the binding force increases is, for example, the strengthening of the chemical bond between a functional group such as a carboxyl group introduced on the surface of the conductive particle 12 and a functional group such as a hydroxyl group introduced on the surface of the insulating particle 13. The heat drying temperature is preferably 60 to 100 ° C., and the time is preferably 10 to 180 minutes. When the temperature is 60 ° C. or higher, the insulating particles 13 are difficult to peel off from the conductive particles 12, and when the temperature is 100 ° C. or lower, the conductive particles 12 are difficult to deform. Similarly, if the heat drying time is 10 minutes or longer, the insulating particles are difficult to peel off, and if it is 180 minutes or shorter, the conductive particles 12 are difficult to deform.

  The insulating coated conductive particles 4 having functional groups on the surface can be further surface treated with a silicone oligomer, octadecylamine or the like. Thereby, the insulation reliability of the insulation coating conductive particles 4 can be improved, and the insulation coating conductive particles having excellent insulation reliability can be obtained. Furthermore, insulation reliability can be further improved by using a condensing agent as required.

  The insulating coated conductive particles 4 produced as described above can be used as an anisotropic conductive adhesive by dispersing in the adhesive 5.

  As the adhesive of the anisotropic conductive adhesive of the present embodiment, a mixture of a thermosetting resin and a curing agent is used. Examples of the thermosetting resin include radical reactive resins, and examples of the curing agent include organic peroxides. Further, energy ray curable resins such as ultraviolet rays are also used. Such a resin, curing agent, organic peroxide, and energy beam can be selected by those skilled in the art as needed.

  In the present embodiment, from the viewpoint of adhesiveness, the thermosetting resin constituting the adhesive is preferably an epoxy resin. Epoxy resins used include bisphenol-type epoxy resins derived from epichlorohydrin, bisphenol A, bisphenol F, bisphenol AD, etc., epoxy novolac resins derived from epichlorohydrin, phenol novolac, cresol novolac, etc., and a skeleton containing a naphthalene ring. Examples thereof include compounds having two or more glycidyl groups in one molecule such as naphthalene epoxy resin, glycidylamine, glycidyl ether, biphenyl, and alicyclic. These epoxy resins may be used alone or in combination of two or more.

For these epoxy resins, it is preferable to use high-purity products in which impurity ions (Na ⁺ , Cl ^{− and the} like), hydrolyzable chlorine and the like are reduced to 300 ppm or less, in order to prevent electromigration.

  As the curing agent, for example, a latent curing agent is used. Examples of the latent curing agent include imidazole, hydrazide, boron trifluoride-amine complex, sulfonium salt, amine imide, polyamine salt, dicyandiamide, and the like.

  In order to reduce the stress after adhesion or to improve the adhesion, the adhesive may further contain a rubber such as butadiene rubber, acrylic rubber, styrene-butadiene rubber, silicone rubber or the like.

  The anisotropic conductive adhesive can be used as a film or a paste. In order to make the anisotropic conductive adhesive into a film, it is effective to blend a thermoplastic resin such as phenoxy resin, polyester resin, polyamide resin or the like into the adhesive as a film-forming polymer. These thermoplastic resins also have a stress relieving effect when the thermosetting resin is cured. In addition, it is more preferable that the film-forming polymer has a functional group such as a hydroxyl group because the adhesiveness is improved.

  The anisotropic conductive adhesive film includes, for example, a step of dissolving or dispersing an adhesive composed of an epoxy resin, acrylic rubber, and a latent curing agent, and insulating coating conductive particles 4 in an organic solvent to liquefy, It can be obtained by a method comprising a step of applying a liquid composition containing an organic solvent on a peelable substrate and a step of removing the organic solvent from the applied liquid composition at a temperature lower than the activation temperature of the curing agent. . The organic solvent used at this time is preferably a mixed solvent of an aromatic hydrocarbon type and an oxygen-containing type from the viewpoint of improving the solubility of the material.

  In the anisotropic conductive adhesive film, the adhesive layer is preferably multilayered. For example, an anisotropic conductive adhesive film having a two-layer structure obtained by laminating a conductive adhesive layer and an insulating adhesive layer to provide anisotropic conductivity, and a conductive adhesive layer, and insulating on both sides. Examples thereof include an anisotropic conductive adhesive film having a three-layer structure in which an adhesive layer is laminated. In addition, a conductive contact bonding layer contains the above-mentioned insulation coating electroconductive particle. By disposing the insulating adhesive layer on the metal bump side and the conductive adhesive layer on the glass side, the insulating coated conductive particles can be efficiently captured on the metal bump side, which is advantageous for narrow pitch connection. .

  The conductive adhesive layer is preferably as thin as possible from the viewpoint of connectivity. On the other hand, the insulating adhesive layer is preferably thicker and more fluid than the conductive adhesive layer. Specifically, the thickness of the conductive adhesive layer is 3 to 15 μm, and the thickness of the insulating adhesive layer is 7 to 20 μm. When the thickness of the conductive adhesive layer is 3 μm or more and 15 μm or less, better connectivity can be obtained. When the thickness of the insulating adhesive layer is 7 μm or more and 20 μm or less, the fluidity is excellent.

  Moreover, it is preferable that content of an electroconductive contact bonding layer is 50 mass% or less of the total mass of an anisotropic conductive adhesive film.

  Furthermore, the anisotropic conductive adhesive film preferably has a three-layer structure in which an insulating adhesive layer is disposed on both surfaces of the conductive adhesive layer in order to enhance the adhesiveness with the glass substrate or ITO. The thickness of the two insulating adhesive layers in the anisotropic conductive adhesive film having such a three-layer structure may be the same or different. For example, one is preferably 2 to 15 μm and the other is preferably 7 to 20 μm. .

  One embodiment of a method for producing a connection structure using the anisotropic conductive adhesive will be described with reference to FIG.

  FIG. 2 is a cross-sectional view showing an embodiment of a circuit connection method using an anisotropic conductive adhesive using the insulating coated conductive particles of the present invention. A first circuit member 20 having an IC chip 1 and metal bumps 2 provided on the IC chip, and a second circuit member 30 having a glass substrate 8 and an electrode 7 provided on the glass substrate, The metal bumps 2 and the electrodes 7 are arranged so as to face each other. An anisotropic conductive adhesive 9 is disposed between the first circuit member 20 and the second circuit member 30. The electrode 7 is an ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide) electrode. The anisotropic conductive adhesive 9 is insulated from the insulating adhesive layer 3 disposed on the first circuit member 20 side, the insulating adhesive layer 6 disposed on the second circuit member 30 side, and the insulating adhesive layer 3. This is a three-layer configuration of a conductive adhesive layer 40 disposed between the conductive adhesive layer 6 and the conductive adhesive layer 6. The conductive adhesive layer 40 is composed of the adhesive 5 and the insulating coated conductive particles 4 dispersed in the adhesive.

  By heating and pressurizing the whole in such a state, a connection structure 100 in which the first circuit member 20 and the second circuit member 30 are connected as shown in the cross-sectional view of FIG. 3 is obtained. It is done. The heating and pressurizing conditions are appropriately adjusted according to the curability of the adhesive 5 in the anisotropic conductive adhesive 9 so that the anisotropic conductive film is cured and sufficient adhesive strength is obtained. can do. In the connection structure manufactured in this way, the conductive particles are easily captured on the metal bumps 2, so that higher conduction reliability is obtained between the metal bumps and the glass substrate 8. In addition, the improvement in the capture rate reduces the proportion of conductive particles flowing between adjacent circuit electrodes, thereby improving the insulation reliability.

(Preparation of conductive particles 1)
10 g of a plastic core composed of a copolymer of divinylbenzene and acrylic acid having an adjusted degree of crosslinking and having a carboxyl group on the surface was prepared. The average particle size of the plastic core was 2.6 μm.

The hardness of the plastic core was 2,746 MPa (280 kgf / mm ² ). The hardness was measured as a compression elastic modulus and 20% K value when the particle diameter was displaced by 20% at 200 ° C.

  Next, electroless nickel plating and electroless palladium plating were performed in this order on the plastic core to produce conductive particles. The thickness of the obtained nickel layer was 100 nm, and the thickness of the palladium layer was 16 nm.

(Preparation of insulating particles 1-9)
Monomers were added in 400 g of pure water in a 500 ml flask according to the blending molar ratio shown in Table 1. It mix | blended so that the total amount of all the monomers might be 10 mass% with respect to pure water. After nitrogen substitution, heating was performed for 6 hours with stirring at 70 ° C. The stirring speed was 300 min ⁻¹ (300 rpm). In Table 1, KBM-503 (trade name, manufactured by Shin-Etsu Silicone Co., Ltd.) is 3-methacryloxypropyltrimethoxysilane.

  The average particle diameter of the synthesized insulating particles 1 to 9 was measured by image analysis of HITACHI S-4800 (manufactured by Hitachi High-Tech Co., Ltd., trade name). The results are shown in Table 1.

  Tgs of the synthesized insulating particles 1 to 9 were measured using DSC (DSC-7 model, manufactured by Perkin Elmer) under the conditions of a sample amount of 10 mg, a heating rate of 5 ° C./min, and a measurement atmosphere: air.

(Preparation of silicone oligomer 1)
A solution containing 118 g of 3-glycidoxypropyltrimethoxysilane and 5.9 g of methanol was added to a glass flask equipped with a stirrer, a condenser and a thermometer. Further, 5 g of activated clay and 4.8 g of distilled water were added and stirred at 75 ° C. for a certain time, and then a silicone oligomer having a weight average molecular weight of 1300 was obtained. The obtained silicone oligomer has a methoxy group or a silanol group as a terminal functional group that reacts with a hydroxyl group. Methanol was added to the obtained silicone oligomer solution to prepare a treatment liquid having a solid content of 20% by weight.

In addition, the weight average molecular weight of the silicone oligomer was measured by a gel permeation chromatography method (GPC) method, and was calculated by conversion using a standard polystyrene calibration curve. The GPC conditions are shown below.
GPC conditions Pump: Hitachi L-6000 type (trade name, manufactured by Hitachi, Ltd.)
Column: Gelpack GL-R420, Gelpack GL-R430, Gelpack GL-R440 (above, Hitachi Chemical Co., Ltd., trade name)
Eluent: Tetrahydrofuran (THF)
Measurement temperature: 40 ° C
Flow rate: 2.05 mL / min Detector: Hitachi L-3300 type RI (trade name, manufactured by Hitachi, Ltd.)

[Insulation coated conductive particles]
(Insulation coated conductive particles 1)
A reaction solution was prepared by dissolving 8 mmol of mercaptoacetic acid in 200 ml of methanol. Next, 10 g of the conductive particles 1 was added to the reaction solution, and the mixture was stirred at room temperature for 2 hours with a three-one motor and a stirring blade having a diameter of 45 mm. After washing with methanol, 10 g of conductive particles having a carboxyl group on the surface was obtained by filtering using a membrane filter (manufactured by Millipore) having a pore size of 3 μm.

  Next, a 30% polyethyleneimine aqueous solution (manufactured by Wako Pure Chemical Industries, Ltd.) having a weight average molecular weight of 70,000 was diluted with ultrapure water to obtain a 0.3 wt% polyethyleneimine aqueous solution. 10 g of conductive particles having a carboxyl group on the surface were added to a 0.3 wt% polyethyleneimine aqueous solution and stirred at room temperature for 15 minutes. Thereafter, the conductive particles were filtered using a membrane filter (manufactured by Millipore) having a pore size of 3 μm, and the filtered conductive particles were put in 200 g of ultrapure water and stirred at room temperature for 5 minutes. Furthermore, the conductive particles were filtered using a membrane filter (manufactured by Millipore) having a pore diameter of 3 μm, and washed twice with 200 g of ultrapure water on the membrane filter. By performing these operations, unimsorbed polyethyleneimine was removed, and conductive particles whose surface was coated with an amino group-containing polymer were obtained.

  Next, the insulating particles 1 were treated with the silicone oligomer 1 to prepare a methanol dispersion medium of the insulating particles 1 having a glycidyl group-containing oligomer on the surface (methanol dispersion medium of the first insulating particles). On the other hand, the insulating particles 6 were similarly treated with the silicone oligomer 1 to prepare a methanol dispersion medium of the insulating particles 6 having a glycidyl group-containing oligomer on the surface (methanol dispersion medium of the second insulating particles).

  The conductive particles whose surfaces were coated with an amino group-containing polymer were immersed in isopropyl alcohol, and a methanol dispersion medium of first insulating particles was dropped. The coverage of the first insulating particles was adjusted by the amount of the methanol dispersion medium dropped on the insulating particles 1. Subsequently, the insulation coating electroconductive particle 1 was produced by dripping the methanol dispersion medium of the 2nd insulating particle. The coverage of the second insulating particles was adjusted by the amount of the insulating particles 6 dropped.

  The obtained insulating coated conductive particles 1 were treated with a condensing agent and octadecylamine and washed to make the surface hydrophobic. Thereafter, the insulating coated conductive particles 1 were produced by heating and drying at 80 ° C. for 1 hour.

(Insulating coated conductive particles 2 to 11)
Insulating coated conductive particles 2 to 11 were produced in the same manner as the insulating coated conductive particles 1 except that the first insulating particles and the second insulating particles listed in Table 2 were used.

Example 1
300 g of a solvent in which ethyl acetate and toluene are mixed at a weight ratio of 1: 1, 100 g of phenoxy resin (trade name: PKHC, manufactured by Union Carbide), acrylic rubber (40 parts by weight of butyl acrylate, 30 parts by weight of ethyl acrylate, 30 parts of acrylonitrile) By weight, a copolymer of 3 parts by weight of glycidyl methacrylate and 75 g of a weight average molecular weight: 850,000) were dissolved to obtain a solution. Liquid epoxy (Eboxy equivalent 185, manufactured by Asahi Kasei Epoxy Co., Ltd., trade name: NovaCure HX-3941) containing a microcapsule type latent curing agent in this solution, and liquid epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd., commercial product) Name: YL980) 400 g was added and stirred. A silica slurry (manufactured by Nippon Aerosil Co., Ltd., trade name: R202) in which silica having an average particle diameter of 14 nm was dispersed in a solvent was added to the obtained mixed solution to prepare an adhesive solution 1. The silica slurry was added so that the content of the silica solid content was 5% by weight with respect to the total solid content of the mixed solution.

  In a beaker, 10 g of a dispersion medium in which ethyl acetate and toluene were mixed at a weight ratio of 1: 1 and the insulating coated conductive particles 1 were placed and ultrasonically dispersed. The ultrasonic dispersion was performed by immersing the above beaker in an ultrasonic bath (Fujimoto Kagaku, trade name: US107) having a frequency of 38 kHz, energy of 400 W, and volume of 20 L, and stirring for 1 minute.

The obtained dispersion liquid of insulating coated conductive particles 1 was dispersed in the adhesive solution 1. The obtained dispersion was applied to a separator (silicone-treated polyethylene terephthalate film, thickness 40 μm) with a roll coater and dried at 90 ° C. for 10 minutes to prepare an adhesive film A having a thickness of 10 μm. This adhesive film has 70,000 pieces / mm ² of insulating coated conductive particles per unit area.

  Further, the adhesive solution 1 was applied to a separator (silicone-treated polyethylene terephthalate film, thickness 40 μm) with a roll coater, and dried at 90 ° C. for 10 minutes to prepare an adhesive film B having a thickness of 3 μm.

  Further, the adhesive solution 1 was applied to a separator (silicone-treated polyethylene terephthalate film, thickness 40 μm) with a roll coater and dried at 90 ° C. for 10 minutes to prepare an adhesive film C having a thickness of 10 μm.

  Next, each adhesive film was laminated in the order of adhesive film B, adhesive film A, and adhesive film C, and anisotropic conductive adhesive film D consisting of three layers was produced.

(Example 2)
An anisotropic conductive adhesive film D was prepared in the same manner as in Example 1 except that the insulating coated conductive particles 2 were used instead of the insulating coated conductive particles 1.

(Example 3)
An anisotropic conductive adhesive film D was produced in the same manner as in Example 1 except that the insulating coated conductive particles 3 were used instead of the insulating coated conductive particles 1.

Example 4
An anisotropic conductive adhesive film D was produced in the same manner as in Example 1 except that the insulating coated conductive particles 4 were used instead of the insulating coated conductive particles 1.

(Example 5)
An anisotropic conductive adhesive film D was produced in the same manner as in Example 1 except that the insulating coated conductive particles 5 were used instead of the insulating coated conductive particles 1.

(Example 6)
An anisotropic conductive adhesive film D was produced in the same manner as in Example 1 except that the insulating coated conductive particles 6 were used instead of the insulating coated conductive particles 1.

(Example 7)
An anisotropic conductive adhesive film D was produced in the same manner as in Example 1 except that the insulating coated conductive particles 7 were used instead of the insulating coated conductive particles 1.

(Example 8)
An anisotropic conductive adhesive film D was produced in the same manner as in Example 1 except that the insulating coated conductive particles 8 were used instead of the insulating coated conductive particles 1.

(Comparative Example 1)
An anisotropic conductive adhesive film D was produced in the same manner as in Example 1 except that the insulating coated conductive particles 9 were used instead of the insulating coated conductive particles 1.

(Comparative Example 2)
An anisotropic conductive adhesive film D was produced in the same manner as in Example 1 except that the insulating coated conductive particles 10 were used instead of the insulating coated conductive particles 1.

(Comparative Example 3)
An anisotropic conductive adhesive film D was produced in the same manner as in Example 1 except that the insulating coated conductive particles 11 were used instead of the insulating coated conductive particles 1.

[Preparation of connection sample]
Using the anisotropic conductive adhesive film D produced in Examples and Comparative Examples, a chip (area 1.times.90 μm ² , space 8 μm, height 15 μm, number of bumps 362) provided with metal bumps. 7 × 1.7 mm ² and a thickness of 0.5 μm) and a glass substrate (thickness 0.7 mm) provided with electrodes were connected as shown below.

After the anisotropic conductive adhesive film D was attached to a glass substrate equipped with electrodes under conditions of a temperature of 80 ° C. and a pressure of 0.98 MPa (10 kgf / cm ² ), the separator was peeled off to prepare for the chip. The glass substrate provided with the bumps and the electrodes are aligned. Next, heating and pressurization were performed for 10 seconds from above the chip under the conditions of a temperature of 190 ° C. and a pressure of 39 N / bump (40 gf / bump) to perform the main connection. The anisotropic conductive adhesive film D was disposed such that the adhesive film B was on the glass substrate side and the adhesive film C was on the metal bump side.

[Insulation resistance test and conduction resistance test]
An insulation resistance test and a conduction resistance test were performed on the anisotropic conductive adhesive films prepared in Examples and Comparative Examples. It is important that the anisotropic conductive adhesive film has high insulation resistance between metal bumps and low conduction resistance between metal bumps / glass side electrodes. Regarding the insulation resistance between the metal bumps, an initial value was measured, and the value of the insulation resistance was calculated from an average value of 20 samples. In addition, the yield when the insulation resistance is 10 ⁹ Ω or more was calculated, and a product with a yield of 80% or more was regarded as a good product. The moisture absorption heat resistance test was conducted by energizing at 20 V for 100 hours under conditions of an air temperature of 60 ° C. and a humidity of 90%.

  Moreover, regarding the conduction resistance between the metal bump / glass substrate side electrode, the initial value and the value after the moisture absorption heat test were measured, and the value of the conduction resistance was calculated from the average value of 14 samples. In addition, the moisture absorption heat test was performed by leaving it to stand for 500 hours under conditions of an air temperature of 85 ° C. and a humidity of 85%.

[Insulation particle coverage]
The total coverage of the insulating particles (the coverage with the first and second insulating particles) was calculated by the above-described method by taking an SEM photograph of the insulating coated conductive particles and analyzing the image. The coverage was measured immediately after production. Further, the coverage of the first insulating particles was measured in the same manner after the first insulating particles were coated on the conductive particles.

  Table 3 shows the measurement results. According to the sample of each Example, the insulation coating electroconductive particle which is excellent in both insulation reliability and conduction | electrical_connection reliability can be provided.

  DESCRIPTION OF SYMBOLS 1 ... IC chip, 2 ... Metal bump, 3 ... Insulating adhesive layer, 4 ... Insulation coating conductive particle, 5 ... Adhesive, 5a ... An anisotropic conductive adhesive layer after hardening, 6 ... Insulating adhesive layer, 7 DESCRIPTION OF SYMBOLS ... Glass substrate side electrode, 8 ... Glass substrate, 9 ... Anisotropic conductive adhesive, 10 ... Plastic core, 11 ... Metal coating, 12 ... Conductive particle, 13 ... Insulating particle, 13a ... 1st insulating particle, 13b 2nd insulating particle, 20 ... 1st circuit member, 30 ... 2nd circuit member, 40 ... Conductive adhesive layer, 100 ... Connection structure.

Claims (11)

Insulating coated conductive particles comprising conductive particles and a plurality of insulating particles attached to the outside of the conductive particles,
The conductive particles have an average particle size of 1 to 10 μm,
Insulating coated conductive particles, wherein the insulating particles include first insulating particles and second insulating particles having a glass transition temperature lower than that of the first insulating particles.   The insulating coated conductive particles according to claim 1, wherein a coverage of the conductive particles by the first insulating particles and the second insulating particles is 35 to 75% with respect to a total surface area of the conductive particles. .   The insulating coated conductive particles according to claim 1 or 2, wherein an average particle diameter of the first insulating particles is larger than an average particle diameter of the second insulating particles.   The insulating coated conductive particles according to any one of claims 1 to 3, wherein an average particle diameter of the first insulating particles is larger than 200 nm and not larger than 500 nm.   The insulating coated conductive particles according to any one of claims 1 to 4, wherein an average particle diameter of the second insulating particles is 50 to 200 nm.   The insulating coated conductive particles according to claim 1, wherein a glass transition temperature of the second insulating particles is 10 ° C. or more lower than a glass transition temperature of the first insulating particles.   The insulating coated conductive particles according to any one of claims 1 to 6, wherein the glass transition temperature of the second insulating particles is 80 to 120 ° C.   The insulating coated conductive particles according to claim 1, wherein the first insulating particles have a glass transition temperature of 100 to 150 ° C.   An anisotropic conductive adhesive containing the insulating coated conductive particles according to claim 1. The anisotropic conductive adhesive is interposed between a first circuit member having a first connection terminal and a second circuit member having a second connection terminal, and is heated and pressed to thereby form the first circuit member. An anisotropic conductive adhesive for electrically connecting the first connection terminal and the second connection terminal;
The anisotropic conductive adhesive according to claim 9, wherein a heating temperature in the heating and pressurization is 30 ° C. or more higher than a glass transition temperature of the second insulating particles. The anisotropic conductive adhesive is interposed between a first circuit member having a first connection terminal and a second circuit member having a second connection terminal, and is heated and pressed to thereby form the first circuit member. An anisotropic conductive adhesive for electrically connecting the first connection terminal and the second connection terminal;
The anisotropic conductive adhesive according to claim 9 or 10, wherein a heating temperature in the heating and pressing is higher than a glass transition temperature of the first insulating particles.

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