JP6507551B2 - Conductive particles - Google Patents

Description

  The present invention relates to conductive particles suitably used for anisotropic conductive adhesives.

  Methods of mounting a driving IC on a liquid crystal or a glass panel for OLED (Organic Light-Emitting Diode) display are roughly classified into two types, COG (Chip-on-Glass) mounting and COF (Chip-on-Flex) mounting. be able to. In COG mounting, the drive IC is bonded directly onto the glass panel using an anisotropic conductive adhesive that contains conductive particles. On the other hand, in the COF mounting, a driving IC is bonded to a flexible tape having metal wiring, and they are bonded to a glass panel using an anisotropic conductive adhesive containing conductive particles. The term "anisotropy" as used herein means conducting in the pressure direction and maintaining insulation in the non-pressure direction. In the past, ITO (Indium Tin Oxide) wiring was the mainstream for the wiring on the glass panel, but is being replaced by IZO (Indium Zinc Oxide) for the purpose of improving productivity and smoothness.

  Furthermore, in recent years, electrodes in which a plurality of metal layers such as Cu and Al, Ti layers and the like are laminated on a glass panel, and composite multilayer electrodes in which ITO and IZO are formed on the surface have been developed. With an electrode having high smoothness such as an IZO electrode, it is likely that it will be difficult to ensure conductivity with ordinary conductive particles. When a layer of Ti or Cr is formed on the surface of a metal layer which is easily oxidized or corroded such as Cu, Al or Mo, the surface of Ti or Cr is oxidized by the air to form an oxidized layer. With conventional conductive particles, this oxide layer can not be pierced at the time of mounting, which causes a problem in lowering the connection resistance.

  By the way, the Au electrode formed in the IC is being narrowed, and it is required to secure insulation between adjacent electrodes. As conductive particles used for the anisotropic conductive adhesive, metal particles such as Ni particles and particles having a gold layer provided on the surface thereof to enhance conductivity have been used (for example, patent documents) 1 to 2).

Since Ni particles have hardness, they can bite into the electrode well and gain contact area, but since the specific gravity is heavy, monodispersion in anisotropic conductive adhesive is low, for example, film-like In the case of coating on the film, there was a problem such as sedimentation in the lower layer direction of the film during the drying step and low monodispersity in the surface direction. In addition, since Ni particles have a wide particle size distribution due to the limit of their manufacturing technology, there is a problem that a short pitch is likely to occur in a narrow pitch electrode.
Then, the electrically-conductive particle which provided the metal electrically conductive layer in the surface of the resinous particle | grains with narrow particle size distribution as a method of solving these has been developed (for example, refer patent documents 3-4).

  The conductive particle provided with the metal conductive layer has a specific gravity smaller than that of the metal particle and has a narrow particle size distribution, so that even in the case of a narrow pitch electrode, there is an advantage that the occurrence of short circuit can be suppressed. Furthermore, conductive particles having protrusions on the surface have been developed, and the conductivity has been improved (see, for example, Patent Documents 5 to 10).

Japanese Patent Application Laid-Open No. 9-31419 Patent No. 4188278 Patent No. 4278374 Patent No. 4188278 Patent No. 5184612 Patent No. 3083535 Patent No. 4243279 Patent No. 4860163 Patent No. 4718926 Patent No. 4640531

It is said that the resistance can be improved by enhancing the removability of the resin interposed between the conductive layer and the electrode and by increasing the contact area to the electrode. In recent years, electrode materials and configurations have become complicated and diversified along with cost reduction and expansion of application fields, and further improvement of the conductivity of conductive particles is also required. As a result of the inventor's sincere investigation, in the conductive particle developed so far, the resin between the conductive layer and the electrode is not sufficiently eliminated, and the conductive layer does not fit into the electrode sufficiently, so the connection resistance is sufficiently improved It turned out that I might not.
Therefore, an object of the present invention is to provide a conductive particle capable of obtaining sufficient conductivity even when used in an anisotropic conductive adhesive for connecting a smooth electrode.

The present invention comprises a base particle having a nonconductive inorganic particle and a nonconductive inorganic core material disposed on the surface of the nonconductive inorganic particle, and a metal plating layer covering the base particle, the metal plating A layer has the surface which forms a projection part, and the said nonelectroconductive inorganic particle and the said nonelectroconductive inorganic core material are related with the electrically conductive particle which is harder than a metal plating layer.
The metal plating layer has projections, and the nonconductive inorganic particles and the nonconductive inorganic core material are harder than the metal plating layer. The conductive particle according to the present invention can obtain sufficient conductivity even when it is used for an anisotropic conductive adhesive for connecting a smooth electrode by having the above specific configuration. It has become possible.
In the conductive particles according to the present invention, it is preferable that the nonconductive inorganic particles and the nonconductive core material constituting the conductive particles are both harder than the material constituting the thickest layer of the electrode.
The conductive particle according to the present invention is provided with the above-mentioned specific feature, whereby when the electrodes facing each other are electrically connected by pressure bonding, the projection portion is sufficiently pushed into the electrode and stable conductivity can be obtained. .
In the conductive particles according to the present invention, it is preferable that 90% by mass or more of all of the nonconductive inorganic particles and the nonconductive inorganic core material constituting the conductive particles be SiO ₂ .
The conductive particle according to the present invention is provided with the above-mentioned specific feature, whereby when the electrodes facing each other are electrically connected by pressure bonding, the projection portion is sufficiently pushed into the electrode and stable conductivity can be obtained. .
The conductive particles according to the present invention preferably contain any of nickel, copper, tin, palladium and gold in the metal plating layer, thereby reliably reducing the electrical connection between opposing electrodes. it can.
Furthermore, these metal plating layers are preferably formed by electroless plating, which makes it possible to form a plating layer inexpensive and with less variation in thickness among particles. That is, stable connection can be made between opposing electrodes.
In the conductive particle according to the present invention, the long side of the nonconductive inorganic particle when projected is a, the short side is b, and the long side of the nonconductive inorganic core material when projected. When c and the short side is d, it is preferable that a / b <3 and c / d <5 and a55c, whereby the nonconductive inorganic core material relative to the nonconductive inorganic particles Since the projection part which exists in the metal plating layer part which covers the said nonelectroconductive inorganic core material can earth | ground and squeeze suitably to an opposing electrode because it is small, it enables stable electrical connection.
The present invention also relates to an anisotropic conductive adhesive comprising the above-described conductive particles. The anisotropic conductive adhesive according to the present invention is effective for connecting hard and smooth electrodes.

  ADVANTAGE OF THE INVENTION According to this invention, even when it is used for the anisotropic conductive adhesive for connecting a hard and smooth electrode, the electrically-conductive particle which can acquire sufficient electroconductivity is provided.

It is a sectional view showing one embodiment of electric conduction particles. FIG. 5 is a cross-sectional view of one embodiment of a connection structure. It is a schematic diagram of the part in which the metal plating layer of the electrically-conductive particle of a connection structure and a bump electrode or an electrode are contacting.

Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.
FIG. 1 is a cross-sectional view showing an embodiment of a conductive particle. The conductive particle 1 shown in FIG. 1 is a base particle 5 having a particulate nonconductive inorganic particle 20 and a plurality of nonconductive inorganic core materials 30 disposed on the surface of the nonconductive inorganic particle 20. And a metal plating layer 40 covering the mother particles 5. The metal plating layer 40 also has a protrusion 40a.
The particle size of the conductive particles 1 needs to be smaller than the minimum value of the distance between the electrodes of the connected circuit members. In addition, when there is variation in height of the connected electrodes, the particle diameter of the conductive particles 1 is preferably larger than the variation in height. From the above viewpoints, the particle diameter of the conductive particles 1 is preferably 1 to 15 μm, and more preferably 2 to 10 μm.

  Specifically, when the average value of the long side and the short side of the 100 nonconductive inorganic particles 20 arbitrarily selected in the observation using the SEM (electron microscope) is a long side a and a short side b, a / B <4 is preferable, a / b <3 is more preferable, a / b <2 is more preferable, and a / b <1.3 is particularly preferable. As the non-conductive inorganic particles 20 are closer to a true spherical shape, the contact variation between each particle and the electrode is small, and a stable connection resistance is obtained, which is preferable.

  The material forming the nonconductive inorganic particles 20 is harder than the material forming the metal plating layer 40. Specifically, the material forming the nonconductive inorganic particles is silica (silicon dioxide, Mohs hardness 6 to 7), titanium oxide (Mohs hardness 5.5 to 6.5), zirconia (Mohs hardness 8 to 9) It is preferable to be selected from alumina (Mohs hardness 9) and diamond (Mohs hardness 10). The value of Mohs hardness was referred to Kyoritsu Publishing Co., Ltd. Chemical Dictionary (1962). The Mohs hardness of the material forming the nonconductive inorganic particles is preferably larger than the Mohs hardness of the metal forming the metal plating layer, and specifically, 5 or more is preferable. It is desirable that the nonconductive inorganic particle 20 have a hydroxyl group (-OH) on its surface. The difference between the Mohs hardness of the material forming the nonconductive inorganic particles and the Mohs hardness of the metal forming the metal plating layer is preferably 1.0 or more. When the metal plating layer is a multilayer, the nonconductive inorganic particles are more effective when they are harder than all the metals constituting them.

As the nonconductive inorganic particles 20, silica particles produced by a precipitation method or a sol-gel method can be used. As a representative method, the Stober method etc. may be mentioned. In addition, it is preferable that the smaller the variation in particle diameter, the smaller the variation in the contact between the conductive particles and the electrode and the more stable connection resistance obtained when sandwiched between the opposing electrodes. Specifically, the coefficient of variation CV is preferably 15% or less, more preferably 10% or less, still more preferably 5% or less, and particularly preferably 3% or less.
Moreover, it is preferable that the nonelectroconductive inorganic particle 20 is comprised with the nonelectroconductive inorganic material. Even when the nonconductive inorganic particles 20 are broken and become foreign matter in the process of producing the conductive particles 1, nonconductive materials are preferable because insulation between adjacent electrodes can be maintained.

As the inorganic material, silica (SiO ₂ ), zirconia, titanium, or oxides or carbonized complexes thereof are suitably used. As an inorganic material which can be used, alumina (Al ₂ O ₃ ), titanium oxide (TiO ₂ ) and the like can be mentioned. Specific examples of the silica (SiO ₂ ) particles that can be used for the nonconductive inorganic particles 20 include Hypresica (manufactured by Ube Nitto Kasei Co., Ltd., “Hypresca” is a registered trademark) and Finesphere (manufactured by Nippon Electric Glass Co., Ltd.) "Finesphere" is a registered trademark, SW series (manufactured by JGC Catalysts & Chemicals Co., Ltd.), and the like are suitably used.

  In order to prevent the decrease in connection resistance due to the corrosion of the conductive layer or the electrode and the deterioration of the insulation reliability, it is preferable that the nonconductive inorganic particles 20 have less elution of alkali metal ions and alkaline earth metal ions. Specifically, 0.5 g of particles and 50 g of ultrapure water were put in a fluorine closed container and heated and extracted at 100 ° C. for 12 h, and then the solid-liquid separated extract was analyzed by liquid chromatography to obtain various ion amounts However, it is preferable that all are 100 ppm or less. Moreover, in order to improve the insulation of a narrow pitch electrode, 50 ppm or less is more preferable, 25 ppm or less is more preferable, and 10 ppm or less is particularly preferable.

  The Mohs hardness of the nonconductive inorganic particles 20 is preferably 5 or more. Furthermore, the conductive layer can be reliably pushed into the electrode if the Mohs hardness is 6 or more, which is more preferable.

As the nonconductive inorganic core material 30, the material shown by the nonconductive inorganic particles 20 can be used. The shape of the nonconductive inorganic core material 30 is not particularly limited, such as a rectangle, a polygon, a sphere, or an aggregate thereof, but from the viewpoint of insulation, it does not exceed 3.0 times the longest side and the shortest side Is preferred. When the longest side is disposed in the direction perpendicular to the surface of the nonconductive inorganic particle 20, the height variation of the protruding portion of the conductive layer formed by the nonconductive inorganic core material 30 becomes large, and between the adjacent electrodes There is a concern that the insulation of the
As a material of the non-conductive inorganic core material 30 and non-conductive inorganic particles 20, it is preferable from the viewpoint of maintenance and the cost of the Mohs hardness of more than 90 wt% is silica (SiO _2). Further, more preferably more than 95 wt% is silica (SiO _2), particularly preferably at least 99 mass%.

As the non-conductive inorganic core material 30, if the variation in the height of the protrusions can be controlled low, in addition to the effect of enhancing the insulation property as described above, the protrusions can be reliably pushed into the electrode without variation, so the stability is stable. There is a feature that can obtain the connection resistance. The particles controlling such a particle size, it is preferable to use silica particles fed as a water-dispersed colloidal silica (SiO _2). As a commercial item of water dispersion colloidal silica, for example, Snowtex, Snowtex UP (made by Nissan Chemical Industry Co., Ltd., "Snowtex" is a registered trademark), Quortron PL series (made by Sakai Chemical Industry Co., Ltd., "Cquatron" Registered trademark). These are spherical and easy to obtain as water-dispersed colloidal silica, which is advantageous from the viewpoint of cost. Moreover, the treatment in an aqueous solution is possible due to the presence of hydroxyl groups, and the cost is low.

Further, as the alumina, Tamicron series (made by Daimei Chemical Industries, Ltd.), and as the zirconia, Nanouse (made by Nissan Chemical Industries, Ltd., "Nanouse" is a registered trademark) are suitably used. From the viewpoint of insulation reliability, the concentration of alkali metal ions and alkaline earth metal ions in the dispersion is preferably 100 ppm or less. Inorganic oxide fine particles produced by a hydrolysis reaction of metal alkoxide, so-called sol-gel method are suitable as the nonconductive inorganic core material 30. The Mohs hardness is preferably 5 or more, more preferably 6 or more.
The reason for using the nonconductive inorganic core material 30 is also to prevent insulation failure if it remains as an impurity.

The particle diameter of the nonconductive inorganic core material 30 is preferably 20 to 5000 nm, and more preferably 50 to 2000 nm. These particle sizes are measured by SEM, TEM, specific surface area conversion method by BET method, or X-ray small angle scattering method. When the particle diameter of the nonconductive inorganic core material 30 is small, the conductivity improvement effect tends to be small. When the particle diameter of the nonconductive inorganic core material 30 is large, the insulating property is lowered, and the connection between narrow pitch circuits tends to be disadvantageous.
Specifically, the long side c and the short side are obtained by measuring the long sides and the short sides of 100 non-conductive inorganic core materials 30 arbitrarily selected in observation using SEM and measuring the average value. When the side d is used, c / d <6 is preferable, c / d <5 is more preferable, c / d <4 is more preferable, and c / d <3 is particularly preferable. The non-conductive inorganic core material 30 has less variation in the height of the protrusions of the metal plating layer as it is closer to a spherical shape, and the protrusions can be stably contacted with the electrodes, which is preferable because stable connection resistance can be obtained. .

  The coefficient of variation (C.V.) of the particle diameter of the nonconductive inorganic core material 30 is preferably 10% or less, more preferably 5% or less. The nonconductive inorganic core material 30 is preferably spherical. Even after being made into conductive particles, measurement is possible by the same method, and the coefficient of variation of the size of protrusions measured by image analysis is preferably 10% or less, more preferably 5% or less.

  As a result of intensive investigations by the inventor, in order to simultaneously achieve stable connection resistance between opposing electrodes and insulation between adjacent electrodes, the ratio of nonconductive inorganic particles 20 to nonconductive inorganic core material 30 is limited. I found that there is. The nonconductive inorganic core material 30 serves as a core material for forming the protruding portion of the metal plating layer, and when disposed between the facing electrodes, the metal plating layer is embedded in the electrode, and the resin between the electrode and the metal plating layer The nonconductive inorganic core material 30 is required to be smaller than the nonconductive inorganic particles 20 because it has a role of eliminating That is, the larger the number of protruding portions of the metal plating layer is, the more stably the electrode and the metal plating layer can be connected.

  The average value a of the long sides of the electrode nonconductive inorganic particles 20 and the average value c of the long sides of the nonconductive core material 30 are preferably a ≧ 50c, more preferably a ≧ 25c, and still more preferably a ≧ 10c. , A ≧ 5c is particularly preferred.

  On the other hand, since the resin of the metal plating layer and the electrode layer needs to be sufficiently removed and it is necessary to increase the connection area when the protrusion is embedded in the electrode, the protrusion of the non-conductive inorganic core material 30 is too small. Because the size is small and the height of the protrusion is low, an appropriate size is required. Specifically, a ≧ 100 c is preferable, a 80 80 c is more preferable, a 50 50 c is more preferable, and a 30 30 c is particularly preferable.

  As a method of forming the metal plating layer 40, a plating method can be used. In particular, electroless plating which does not require a power source is preferable. The metal plating layer 40 is formed of nickel, copper, palladium, tin, gold or a combination thereof, and an alloy containing nickel, copper, palladium, or gold as a main component from the viewpoint of low electrical resistance and easiness of plating. Preferably. The Mohs hardnesses of nickel, copper, palladium, tin and gold are 3.8, 3.0, 4.5, 1.5 and 2.5 respectively.

  Further, from the viewpoint of preventing ion migration, it is preferable to be formed of nickel, palladium, gold or a combination thereof. When these combinations are employed, it is preferable to perform displacement plating of palladium or gold after nickel plating in view of the workability of plating.

  Also, the metal plating layer 40 may have a plurality of layers of a first layer and a second layer. Nickel and nickel alloys can be used as the first layer. Specifically, nickel-phosphorus, nickel-boron, nickel-boron-phosphorus, nickel-tungsten, nickel-phosphorus-tungsten, nickel-phosphorus-boron-tungsten, nickel-boron-tungsten and the like can be mentioned. As the first layer, a layer containing copper can be used, and a layer made of 97% by mass or more copper may be used, but from the viewpoint of suppressing aggregation of particles and suppressing generation of pinholes, nickel It is preferable that the layer containing nickel and copper in which the total of the content and the content of copper is 97% by mass or more. The first layer containing nickel and copper has a portion where the elemental ratio of copper to nickel increases as the distance from the surface of the nonconductive inorganic particles 20 increases. This portion may be a layer provided so as to be a part of the thickness direction of the first layer containing nickel and copper and to cover substantially the whole or the whole of the nonconductive inorganic particles 20.

Specifically, in order of proximity to the nonconductive inorganic particles 20, a first portion containing 97% by mass or more of nickel, a second portion containing an alloy containing nickel and copper as main components, and copper It is preferable that it has a structure in which a third portion which is a main component is laminated.
The first part contains 97% by mass or more of nickel. The content of nickel in the first portion is more preferably 98.5% by mass or more, and still more preferably 99.5% by mass or more. When the conductive particles 1 are crimped and connected by keeping the adhesion between the non-conductive inorganic particles and the first layer containing nickel and copper excellent when nickel is 97% by mass or more, nickel and copper It is possible to suppress peeling of the first layer containing and the nonconductive inorganic particles. The upper limit of the content of nickel is 100% by mass.
The third portion may have a fourth portion containing 83% by weight to 99.5% by weight of nickel outside the third portion. Having the fourth portion can prevent oxidation, elution, and deformation of copper forming the third portion. As nickel forming the fourth part, the nickel and nickel alloys specifically shown in the first layer can be used. By having the first portion, the second portion, the third portion, and the fourth portion as the first layer, conductive particles having stable conductivity can be provided.

  A second layer can also be provided outside the first layer. As the second layer, palladium which has the effect of suppressing oxidation and elution of nickel and copper which form the first layer can be used to further enhance the conductivity of the metal plating layer, and gold which can reduce resistance can be used. It is also possible to have a plurality of layers having palladium on the surface of the first layer and gold on the surface of the palladium as the second layer. Forming the second layer containing palladium and gold is preferable because it can reduce resistance while simultaneously suppressing oxidation and elution of the first layer.

It is desirable that a functional group selected from a hydroxyl group, a carboxyl group, an alkoxy group, an amino group, a glycidyl group and an alkoxycarbonyl group be present on the surfaces of the nonconductive inorganic particles 20 and the nonconductive inorganic core material 30. By the presence of these functional groups, the nonconductive inorganic particles 20 and the nonconductive inorganic core material 30 can be firmly fixed. For example, non-conductive inorganic particles or non-conductive inorganic core materials can be treated with a silane coupling agent to introduce various functional groups.
The mother particles 5 may further include a polymer electrolyte layer provided between the nonconductive inorganic particles 20 and the nonconductive inorganic core material 30. In this case, the nonconductive inorganic core material 30 is disposed on the surface of the nonconductive inorganic particles 20 by chemical bonding via the polymer electrolyte layer. For example, the nonconductive inorganic particle 20, the polymer electrolyte layer, and the nonconductive inorganic core material 30 each have a functional group, and the functional group of the polymer electrolyte layer is a nonconductive inorganic particle and a nonconductive material. It may be chemically bonded to the functional group of each of the inorganic particles. Chemical bonds include covalent bonds, hydrogen bonds, ionic bonds and the like.

  The surface potential (zeta potential) of the nonconductive inorganic particle 20 having a hydroxyl group and the nonconductive inorganic core material 30 is usually negative when the pH is in the neutral region. The surface potential of particles having on the surface a functional group selected from a hydroxyl group, a carboxyl group, an alkoxy group, a glycidyl group and an alkoxycarbonyl group is also usually negative. On the other hand, in many cases it is difficult to sufficiently cover the surface of particles with a negative surface potential with particles with a negative surface potential, but by providing a polymer electrolyte layer between them, it is possible to efficiently form a non-conductive inorganic material The nonconductive inorganic core material 30 can be disposed on the surface of the particles 20.

As a polymer electrolyte which forms a polymer electrolyte layer, it ionizes in aqueous solution and the polymer which has a functional group which has electric charge in a principal chain or a side chain can be used, A polycation is preferable. Polycations generally include those having functional groups capable of being positively charged, such as polyamines, for example, polyethyleneimine (PEI), polyallylamine hydrochloride (PAH), polydiallyldimethyl ammonium chloride (PDDA), Polyvinylpyridine (PVP), polylysine, polyacrylamide and copolymers containing at least one or more of them can be used. Among polyelectrolytes, polyethylenimine has high charge density and strong bonding power.
The polymer electrolyte layer is made of alkali metal (Li, Na, K, Rb, Cs) ion, alkaline earth metal (Ca, Sr, Ba, Ra) ion, halide ion (in order to avoid electromigration and corrosion). It is preferable that substantially no fluorine ion, chlorine ion, bromine ion, iodine ion) be contained.

The polymer electrolyte is water soluble and soluble in a mixture of water and an organic solvent. The molecular weight of the polymer electrolyte can not be generally determined depending on the type of polymer electrolyte used, but generally, about 500 to 200,000 is preferable.
By adjusting the type and molecular weight of the polymer electrolyte, the polymer electrolyte can be adsorbed to the nonconductive inorganic particles 20 or the nonconductive inorganic core material 30 to form a polymer electrolyte layer. Due to the provision of the polymer electrolyte layer, it is adsorbed mainly by electrostatic attraction. As the adsorption proceeds and the charge is neutralized, further adsorption does not occur. Therefore, the film thickness does not substantially increase after reaching a certain saturation point.

  After the nonconductive inorganic particles 20 or the nonconductive inorganic core material 30 on which the polymer electrolyte layer is formed are taken out from the polymer electrolyte solution, it is preferable to remove excess polymer electrolyte by rinsing. The rinse is performed using, for example, water, alcohol, or acetone. Ion exchange water (so-called ultra pure water) having a specific resistance value of 18 MΩ · cm or more is preferably used. The non-conductive inorganic particles 20 and the polymer electrolyte adsorbed on the non-conductive inorganic core material 30 are not peeled off in this rinse step because they are electrostatically adsorbed on the surface by chemical bonding. .

  The polymer electrolyte solution is obtained by dissolving a polymer electrolyte in water, a water-soluble organic solvent, or a mixed solvent of water and a water-soluble organic solvent. Water-soluble organic solvents which can be used include, for example, methanol, ethanol, propanol, acetone, dimethylformamide and acetonitrile.

  Generally, the concentration of the polymer electrolyte in the polymer electrolyte solution is preferably about 0.01 to 10% by mass. In addition, the pH of the polymer electrolyte solution is not particularly limited. When the polymer electrolyte is used at a high concentration, the coverage of the nonconductive inorganic particles 20 by the nonconductive inorganic core material 30 tends to be high, and when the polymer electrolyte is used at a low concentration, the nonconductivity is nonconductive. The coverage of the nonconductive inorganic particles 20 by the inorganic core material 30 tends to be low.

Non-conductive inorganic particles such as silica (SiO ₂ ) particles tend to be spherical when the particle diameter is made uniform. The bonding between the spherical nonconductive inorganic particles 20 and the spherical nonconductive inorganic core material 30 is theoretically in point contact. In the case of point contact, the non-conductive inorganic core material 30 may be exfoliated during plating because of insufficient bonding force. In other words, the variation (C.V.) of the coverage by the nonconductive inorganic core material 30 may increase to, for example, about 40% or more.

  When the nonconductive inorganic particles are coated by alternate layering using a polymer electrolyte, since the polymer electrolyte wraps the nonconductive inorganic core material 30, the bonding strength is dramatically improved. From the viewpoint of bonding strength, it is preferable to use a polyelectrolyte having a molecular weight of 10,000 or more. The bonding strength improves with the molecular weight, but when the molecular weight is too high, the particles tend to aggregate. The nonconductive inorganic core material 30 should be coated only in one layer. Multilayer lamination makes it difficult to control the amount of lamination.

  The coverage of the nonconductive inorganic particles 20 by the nonconductive inorganic core material 30 is preferably 10 to 80%, and more preferably 25 to 60%. The coverage in this case can be calculated by image analysis of the central part of the SEM photograph of 100 particles. 80% is the case of almost close packing.

  By forming a metal plating layer by a known method after adsorption of the nonconductive inorganic core material 30, it is possible to produce conductive particles having a metal plating layer having protrusions on the surface. The metal plating layer may be a single layer or may have a laminated structure composed of a plurality of layers. In the case of the laminated structure, in terms of corrosion resistance and conductivity, the metal plating layer preferably has nickel plating provided on the inner side, and a gold plating layer or palladium plating layer laminated on the outer side as the outermost layer. As a method of forming a metal plating layer, there are methods such as displacement plating and electroplating other than electroless plating. Electroless plating is preferred from the viewpoint of simplicity and cost.

  When the electroless plating is performed, the base particles 5 adsorbed to the nonconductive inorganic particles 20 by the nonconductive inorganic core material 30 are dispersed in water by ultrasonic wave. Since the nonconductive inorganic core material 30 is firmly bonded to the nonconductive inorganic particles 20, the nonconductive inorganic core material 30 is less likely to be detached by ultrasonic treatment, which is preferable. The falling-off rate of the nonconductive inorganic core material 30 is preferably 10% or less, more preferably 3% or less, when irradiated with ultrasonic waves for 15 minutes at a resonance frequency of 28 to 38 kHz and an ultrasonic output of 100 W for 15 minutes.

  The plating catalyst may be applied by a conventionally known method, and is not particularly limited. For example, non-conductive inorganic particles with non-conductive inorganic particles adsorbed on the surface are immersed in a palladium ion solution coordinated with 2-aminopyridine, sodium hypophosphite, sodium borohydride, dimethylamine borane, hydrazine, There is a method of reducing palladium ion to metal by adding formalin or the like.

Further, as a method of catalyzing treatment using an acid seeder, there are, for example, the following methods.
The resin particles are dispersed in a stannous chloride solution, subjected to sensitization treatment to adsorb tin ions on the surface of the resin particles, and then washed with water. Next, the resin particles are dispersed in a solution containing palladium chloride, activated with a surface of resin particles to capture palladium ions, and then washed with water. Furthermore, it is dispersed in a solution containing a reducing agent such as sodium hypophosphite, sodium borohydride, dimethylamine borane, hydrazine, formalin, etc. and subjected to a reduction treatment, and palladium ions adsorbed on the surface of the resin particles are metal palladium Reduce to
In these palladium-catalyzed treatment methods, palladium ions are adsorbed on the surface, washed with water, and dispersed in a solution containing a reducing agent to reduce the palladium ions adsorbed on the surface, thereby achieving atomic level reduction. It forms palladium precipitate nuclei of a size.

Subsequently, electroless nickel plating is performed by a known method. As a method of performing electroless nickel plating, an electroless nickel plating solution composed of sodium hypophosphite as a reducing agent is provided with a catalyst by a construction bath and a heated plating bath according to a predetermined method, and the base particles 5 are treated There is a way to The thickness of the metal plating layer is preferably 10 to 300 nm. If the film thickness is less than 10 nm, the plating can not follow the uneven shape, and the conductivity tends to be lowered. When the film thickness exceeds 300 nm, the projections (concave and convex shapes) on the surface of the conductive layer become smooth, and the removability of the adhesive on the electrode surface may be deteriorated.
As described above, conductive particles having a metal plating layer having projections of 20 to 5000 nm on the surface can be produced. The coverage of the projections is preferably in the range of 10 to 80%, and more preferably in the range of 25 to 60%.

In order to improve the insulation, it is preferable to apply gold plating or palladium plating to the surface of the first layer. The thickness of gold plating or palladium plating is preferably in the range of 10 to 50 nm.
Since conductive particles having protrusions on the surface produced as described above have protrusions, shorting may occur when the electrode pitch is narrow. Therefore, it is preferable that the insulating fine particles 35 be adsorbed to partially cover the surface of the metal plating layer. The insulating fine particles 35 are preferably made of a material such as an inorganic material or a resin and having an electrical insulating property. The particle diameter of the insulating fine particles 35 is preferably larger than the particle diameter of the nonconductive inorganic core material 30. If the particle size of the insulating fine particles 35 is smaller than that of the nonconductive inorganic core material 30, there is a tendency that short defects easily occur. Like the adsorption of the nonconductive inorganic core material 30, the adsorption of the insulating fine particles may be performed by adopting an alternate lamination method via a polymer electrolyte layer. Specifically, it is preferable as the inorganic particles are silica (SiO ₂₎ particles.

  FIG. 2 is a cross-sectional view showing an embodiment of the connection structure. The connection structure shown in FIG. 2 includes a first circuit member 60 having a driver IC 61 and a bump electrode 62 provided on the driver IC 61, and a second having a glass substrate 71 and an electrode 72 provided on the glass substrate 71. And the circuit member 70 are connected via the anisotropic conductive adhesive 80.

  The anisotropic conductive adhesive 80 contains a film-like insulating adhesive 81 and the above-described conductive particles 1 dispersed in the insulating adhesive 81. The insulating adhesive 81 contains a thermosetting resin and its curing agent. The insulating adhesive 81 may contain a radical reactive resin as a thermosetting resin and an organic peroxide as a curing agent, or may be an energy ray curable resin such as ultraviolet light.

The thermosetting resin constituting the insulating adhesive 81 is preferably an epoxy resin, and the epoxy resin and its latent curing agent are suitably combined.
Examples of latent curing agents include imidazoles, hydrazides, boron trifluoride-amine complexes, sulfonium salts, amine imides, salts of polyamines, dicyandiamides and the like. As epoxy resins, bisphenol type epoxy resins derived from epichlorohydrin and bisphenol A, F, AD, etc., epoxy novolac resins derived from epichlorohydrin, phenol novolak and cresol novolac, and naphthalene based epoxy resins having a skeleton containing a naphthalene ring It is possible to use various epoxy compounds having two or more glycidyl groups in one molecule, such as glycidyl amine, glycidyl ether, biphenyl and alicyclic, singly or in combination of two or more. As these epoxy resins, it is preferable to use a high purity product 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.

  The insulating adhesive 81 may contain a rubber such as butadiene rubber, acrylic rubber, styrene-butadiene rubber, or silicone rubber in order to reduce stress after bonding or to improve adhesion. In order to make the insulating adhesive 81 into a film, it is effective to blend a thermoplastic resin such as phenoxy resin, polyester resin, polyamide resin or the like with the insulating adhesive 81 as a film forming polymer. These thermoplastic resins also have a stress relaxation effect at the time of curing of the thermosetting resin. In particular, in order to improve adhesion, the film-forming polymer preferably has a functional group such as a hydroxyl group.

  The film-like anisotropic conductive adhesive 80 applies, for example, a liquid composition containing an insulating adhesive, conductive particles, and an organic solvent that dissolves or disperses these on a peelable substrate; And removing the organic solvent from the applied liquid composition at a temperature equal to or 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 in order to improve the solubility of the material. The thickness of the film-like anisotropic conductive adhesive before connection is appropriately determined in consideration of the particle diameter of the conductive particles 1 and the characteristics of the anisotropic conductive adhesive 80, but is preferably 1 to 100 μm. If the thickness is less than 1 μm, adhesion tends to be lowered, and if it exceeds 100 μm, a large amount of conductive particles tends to be required to obtain conductivity. From the same viewpoint, the thickness of the anisotropic conductive adhesive is more preferably 3 to 50 μm.

The anisotropic conductive adhesive does not have to be in the form of a film, and may, for example, be in the form of a paste.
In the connection structure of FIG. 2, the insulating fine particles are peeled off or embedded in the electrodes at the contact portions of the conductive particles 1 with the electrodes, and the opposing electrodes (the direction of the arrow A) conduct. On the other hand, insulating fine particles are interposed between adjacent electrodes on the same substrate (in the direction of the arrow B) to maintain the insulating property. As materials for forming the electrodes, inorganic oxides such as ITO and IZO, gold, copper, nickel, Ti, Cr, Mo, Nd, Al, Sn and the like are used. Mohs hardness is Ti (4.0), Cr (9.0), Mo (5.5), Nd (6.0), Al (3.0), Sn (1.5). The electrode may be configured of a single material as described above, or a plurality of materials may be stacked. <Postscripted>

  FIG. 3 is a schematic view of a portion in which the metal plating layer of the conductive particle 1 of the connection structure is in contact with the bump electrode 62 or the electrode 72. The protrusion 40a of the metal plating layer formed of the nonconductive inorganic core material 30 can be embedded in the electrode, and the contact area between the metal plating layer 40 and the bump electrode 62 or the electrode 72 can be increased to maintain stable connection resistance. .

The nonconductive inorganic particles and the nonconductive inorganic core material are preferably harder than the material constituting the thickest layer of these electrodes. By making the nonconductive inorganic particle and the nonconductive inorganic core material harder than the material constituting the thickest layer of the electrode, the metal plating layer can be sufficiently embedded in the electrode to obtain stable connection resistance. Can do. The electrodes are manufactured in various layer configurations from the viewpoint of the stability of the manufacturing process and cost, but the driver IC side is often made of gold alone, and the panel side is made to exhibit conductivity on the surface of glass or plastic film In many cases, a metal layer is provided and an outermost layer covering the metal layer.
There is also a case in which a layer for exhibiting adhesiveness is provided between the glass on the panel side, the plastic film and the metal layer. In such a configuration, since the outermost layer is for the purpose of preventing oxidation of the metal layer and for the purpose of maintaining smoothness, the outermost layer is often thinner than the metal layer.
That is, the hardness of the material constituting the thickest layer can be substituted as the substantial hardness of the electrode. Therefore, it is preferable that the nonconductive inorganic particles and the nonconductive inorganic core material be harder than the hardness of the thickest material constituting these electrodes. The total thickness of the electrode is preferably 0.05 to 2.0 μm, more preferably 0.1 to 1.5 μm, and particularly preferably 0.2 to 1.0 μm in order to secure the transparency and conductivity of the electrode.

From the surface side, ITO, IZO, ITO / metal layer, ITO / Ti / metal layer, ITO / Ti / metal layer / Ti, ITO / Cr / metal as the composition of the electrode on the glass panel for liquid crystal (LCD) Layer, ITO / Cr / metal layer / Cr, etc. Moreover, as a structure of the electrode on FPC, there exist ITO, IZO, ITO / Cu, IZO / Cu, ITO / Sn / Cu, IZO / Sn / Cu etc. from surface layer side. Specifically, from the surface side, ITO / Ti / Al (0.05 μm / 0.02 μm / 0.15 μm), IZO / Cu (0.05 μm / 0.23 μm), IZO / Sn / Cu (0.04 μm / μm) 0.08 μm / 0.16 μm).
In the case of an OLED, ITO or IZO, which is a transparent electrode material, may not be used, and in general, the total thickness tends to be thicker than an electrode for liquid crystal (LCD). For example, from the surface side, Ti / Al / Ti, Cr / Al / Cr, IZO / Mo / Al / Mo, Ti / metal layer, Mo-Nd / Al-Nd / Mo-Nd, Al-Nd / metal layer, There are Ni-Mo / Mo-Nd / Al / Mo-Nd, ITO / metal layers, etc. Specifically, there are Ti / Al / Ti (0.09 μm / 0.5 μm / 0.9 μm), Ti / Cu (0.16 μm / 0.5 μm), and the like. The thickness of the electrode layer can be selected according to the application and the desired characteristics. In order to obtain transparency, a thickness on the order of micrometers is preferred.

  In any electrode, the metal layer of Cu, Al, Mo or the like tends to be thicker than ITO, Ti or the like. Examples of the material of the electrode provided on the semiconductor (driving IC) chip include copper, gold, nickel, silver, alloys thereof, or a multilayer structure in which these are stacked.

Hereinafter, the present invention will be more specifically described by way of examples. However, the present invention is not limited to these examples.
Example 1
(Preparation of conductive particles)
As nonconductive inorganic particles, 4 g of silica particles Finesphere SK-30 (trade name, manufactured by Nippon Electric Glass Co., Ltd.) having an average particle diameter of 3.0 μm was prepared. The component of this particle was 99.9% by mass or more of SiO ₂ . A 30% by mass polyethyleneimine aqueous solution (manufactured by Wako Pure Chemical Industries, Ltd.) having a molecular weight of 70000 was diluted to 0.3% by mass with ultrapure water. 4 g of the nonconductive inorganic particles were added to 300 mL of this 0.3% by mass aqueous polyethylene solution, and the mixture was stirred at room temperature (25 ° C., the same applies hereinafter) for 15 minutes. The nonconductive inorganic particles were taken out by filtration using a membrane filter (made by Millipore) having a diameter of 3 μm, and the taken out nonconductive inorganic particles were placed in 300 g of ultrapure water and stirred at room temperature for 5 minutes. Next, nonconductive inorganic particles are taken out by filtration using a membrane filter (made by Millipore) having a diameter of 3 μm, and the nonconductive inorganic particles on the membrane filter are washed twice with 200 g of ultrapure water, and polyethylene not adsorbed The imine was removed to obtain nonconductive inorganic particles to which polyethyleneimine was adsorbed.

  As a nonconductive inorganic core material, a colloidal silica dispersion having an average particle diameter of 30 nm was diluted with ultrapure water to obtain a 0.33% by mass silica particle dispersion (total amount of silica: 1 g). The nonconductive inorganic particles to which polyethyleneimine was adsorbed were put there, and stirred at room temperature for 15 minutes. Thereafter, nonconductive inorganic particles were taken out by filtration using a membrane filter (manufactured by Millipore) having a diameter of 3 μm. The nonconductive inorganic particles to which the silica particles were adsorbed were placed in 200 g of ultrapure water and stirred at room temperature for 5 minutes. Thereafter, the nonconductive inorganic particles were taken out by filtration using a membrane filter (manufactured by Millipore) having a diameter of 3 μm, and the nonconductive inorganic particles on the membrane filter were washed twice with 200 g of ultrapure water. The washed nonconductive inorganic particles were dried by heating in order of 80 ° C. for 30 minutes and at 120 ° C. for 1 hour to obtain nonconductive inorganic particles (mother particles 1) having silica particles adsorbed on the surface. .

  After irradiating 4 g of the above-mentioned mother particles for 15 minutes with an ultrasonic wave with a resonance frequency of 28 kHz and an output of 100 W for 8 minutes, 8 It was added to 100 mL of palladium catalyst solution containing% by mass, and stirred at 30 ° C. for 30 minutes while being irradiated with ultrasonic waves. Thereafter, the base particles were taken out by filtration using a membrane filter (made by Millipore) having a diameter of 3 μm, and the taken out base particles were washed with water. The washed mother particles were added to a 0.5 mass% dimethylamine borane solution adjusted to pH 6.0 to obtain surface-activated mother particles.

4.0 g of surface-activated mother particles were dispersed in 1000 mL of water heated to 70 ° C. To this dispersion was added 1 mL of a 1 g / L bismuth nitrate aqueous solution as a plating stabilizer, and then 100 mL of a first layer forming electroless nickel plating solution having the following composition was dropped at a dropping rate of 5 mL / min. After 10 minutes had passed after completion of the dropwise addition, the dispersion to which the plating solution had been added was filtered, and the filtrate was washed with water and then dried with a vacuum dryer at 80 ° C. Thus, a first layer consisting of a nickel-phosphorus alloy film having a thickness of 100 nm shown in Table 1 was formed. In addition, the electroconductive particle 1 obtained by forming a 1st layer was 6g.
(Electroless Nickel Plating Solution for First Layer Formation)
Nickel sulfate ················ 400g / L
Sodium hypophosphite ........... 150 g / L
Sodium tartrate dihydrate ..... 120g / L
Bismuth nitrate aqueous solution (1 g / L) ..... 1 mL / L
The obtained conductive particles 1 had protrusions on the surface.

(Evaluation of protrusions formed on the surface of conductive particles)
The obtained conductive particles 1 were observed at 30,000 times by an SEM apparatus, and the coverage by the projections on the surface of the conductive particles was calculated based on the SEM image. In addition, the number and ratio of projections within a concentric circle having a diameter of 1⁄2 of the diameter of the conductive particles 1 were observed at 30,000 × with a SEM apparatus and calculated based on the SEM image.
The coverage of projections is observed at 30,000 times with an SEM apparatus, and based on the SEM image, the projection-formed portion and the flat portion are distinguished by image analysis in concentric circles having a diameter of 1/2 of the diameter of the conductive particles. The coverage of the projections was obtained by calculating the ratio of the projection forming portion in the concentric circles. The outer diameter of the projection is the area of the circle of the contour of the valley of the projection, which is measured in the concentric projection having a diameter of 1⁄2 of the diameter of the conductive particle in the orthographic plane of the conductive particle. The average value of the diameter calculated when it was regarded as the area was calculated. Specifically, the conductive particles are observed at 30,000 times by an SEM apparatus, and based on the obtained SEM image, the outlines of the protrusions are determined by image analysis, the area of each protrusion is calculated, and the average value is calculated. The outer diameter of the protrusion was determined.

[Production of insulating coated conductive particles]
A 30% by mass aqueous solution of polyethyleneimine having a molecular weight of 70,000 (manufactured by Wako Pure Chemical Industries, Ltd.) was diluted to 0.3% by mass with ultrapure water. 200 g of conductive particles 1 obtained in the same manner as above was added to 300 mL of this 0.3 mass% aqueous solution of polyethyleneimine, and the mixture was stirred at room temperature for 15 minutes. The conductive particles were removed by filtration using a membrane filter (manufactured by Millipore) having a diameter of 3 μm, and the removed conductive particles 1 were placed in 200 g of ultrapure water and stirred at room temperature for 5 minutes. Furthermore, the conductive particles are taken out by filtration using a membrane filter (made by Millipore) having a diameter of 3 μm, and the conductive particles 1 on the membrane filter are washed twice with 200 g of ultrapure water to remove nonadsorbed polyethylenimine. did.

  Next, a colloidal silica dispersion having a diameter of 70 nm was diluted with ultrapure water as insulating fine particles to obtain a 0.1 mass% silica particle dispersion. Thereto, 200 g of the conductive particles 1 treated with the above-mentioned polyethyleneimine was placed and stirred at room temperature for 15 minutes. The conductive particles 1 were removed by filtration using a membrane filter (manufactured by Millipore) having a diameter of 3 μm, and the removed conductive particles 1 were put in 200 g of ultrapure water and stirred at room temperature for 5 minutes. Furthermore, the conductive particles are taken out by filtration using a membrane filter (made by Millipore) having a diameter of 3 μm, and the conductive particles 1 on the membrane filter are washed twice with 200 g of ultrapure water to remove nonadsorbed silica particles. As a result, insulating coated conductive particles 1 in which silica particles were adsorbed on the surface were obtained.

  The surface of the insulating coated conductive particle 1 was hydrophobized by adhering SC6000 (trade name, manufactured by Hitachi Chemical Co., Ltd.), which is a silicone oligomer having a molecular weight of 3000, on the surface of the insulating coated conductive particle 1 obtained. The hydrophobized insulating coated conductive particles 1 were dried by heating in the order of 80 ° C. for 30 minutes and at 120 ° C. for 1 hour to obtain hydrophobized insulating coated conductive particles 1. It was about 40% when the average coverage of the electrically conductive particle 1 by the silica particle which is insulation coating microparticles | fine-particles was measured by carrying out the image analysis of the SEM image.

[Preparation of anisotropic conductive adhesive film and connection structure]
100 g of phenoxy resin (manufactured by Union Carbide Co., Ltd., trade name "PKHC"), acrylic rubber (40 parts by mass of butyl acrylate, 30 parts by mass of ethyl acrylate, 30 parts by mass of acrylonitrile, 3 parts by mass of glycidyl methacrylate, molecular weight: 85 And 75 g were dissolved in 400 g of ethyl acetate to obtain a solution. To this solution is added 300 g of a liquid epoxy resin (epoxy equivalent 185, manufactured by Asahi Kasei E-Materials Co., Ltd., trade name "Novacua HX-3941") containing a microcapsule type latent curing agent, and the solution is stirred. Obtained.
The insulating coated particles 1 obtained above were dispersed in this adhesive solution so as to be 9% by volume based on the total amount of the adhesive solution, to obtain a dispersion. The obtained dispersion is applied to a separator (silicone-treated polyethylene terephthalate film, thickness 40 μm) using a roll coater, and dried by heating at 90 ° C. for 10 minutes to form a 25 μm thick anisotropic conductive adhesive. The film was made on a separator.

Next, using the produced anisotropic conductive adhesive film, a chip (1.7 × 1.7 mm, thickness: 0) with a gold bump (area: 30 × 90 μm, space 10 μm, height: 15 μm, 362 bumps) .5 μm) and the glass substrate (thickness: 0.7 mm) on which the Ti—Al—Ti electrode was formed were performed according to the procedure of i) to iii) shown below to obtain a connection structure. i) An anisotropic conductive adhesive film (2 × 19 mm) was attached to a glass substrate with a Ti—Al—Ti electrode circuit at 80 ° C. and 0.98 MPa (10 kgf / cm ² ). ii) The separator was peeled off, and the bump of the chip and the glass substrate with Ti-Al-Ti electrode circuit were aligned. iii) This connection was performed by heating and pressurizing from above the chip under the conditions of 190 ° C., 40 gf / bump, 10 seconds. The Ti—Al—Ti electrode has a laminated structure of Ti (70 nm), Al (200 nm) and Ti (70 nm) from the glass substrate side.

[Evaluation of connection structure]
The conduction resistance test and the insulation resistance test of the obtained connection structure were performed as follows.
(Conduction resistance test)
Regarding the conduction resistance between the chip electrode (bump) / glass electrode (Ti-Al-Ti electrode), the initial value of the conduction resistance and the moisture absorption heat resistance test (100, 300, 500, 1000 under the conditions of 85 ° C temperature and 85% humidity) The values after standing for time were measured for 20 samples, and their average value was calculated. The conduction resistance was evaluated according to the following criteria from the obtained average value. The results are shown in Table 1. In addition, it can be said that conduction | electrical_connection resistance is favorable, when satisfy | filling the criteria of following A or B 500 hours after a moisture absorption heat resistance test.
A: Average value of conduction resistance is less than 4Ω B: Average value of conduction resistance is 4Ω or more and less than 7Ω C: Average value of conduction resistance is 7Ω or more and less than 12Ω D: Average value of conduction resistance is 12Ω or more and less than 20Ω E: Conduction resistance Average value of 20 Ω or more

(Insulation resistance test)
Regarding the insulation resistance between chip electrodes, the initial value of insulation resistance and the value after migration test (leaved for 100, 300, 500, 1000 hours under the conditions of temperature 60 ° C, relative humidity 90%, 20V application) for 20 samples It measured and calculated the ratio of the sample from which an insulation resistance value becomes 10 < ⁹ > ohm or more in all 20 samples. The insulation resistance was evaluated according to the following criteria from the ratio obtained. The results are shown in Table 1. In addition, it can be said that insulation resistance is favorable when the criteria of the following A or B are satisfy | filled 500 hours after a moisture absorption heat resistance test.
A: 100% of insulation resistance 10 ⁹ Ω or more
B: Ratio of insulation resistance value of 10 ⁹ Ω or more is 90% or more and less than 100% C: Ratio of insulation resistance value of 10 ⁹ Ω or more is 80% or more and less than 90% D: Ratio of insulation resistance value of 10 ⁹ Ω or more is 50% More than 80% E: Insulation resistance 10 ⁹ Ω or more is less than 50%

(Example 2)
Preparation of mother particles having silica particles adsorbed on the surface in the same manner as in Example 1 except that the nonconductive inorganic core material is replaced by a colloidal silica dispersion (total amount of silica: 1 g) having an average particle diameter of 70 nm. And the electroconductive particle 2 which formed the nickel film in the surface of this was produced. Furthermore, using the obtained conductive particles 2, insulating coated conductive particles 2 were obtained by the same procedure as in Example 1 except that a colloidal silica dispersion having a diameter of 100 nm was used as the insulating fine particles. An anisotropic conductive adhesive film and a connected structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 2.

(Example 3)
Preparation of mother particles in which silica particles are adsorbed on the surface in the same manner as in Example 1 except that the nonconductive inorganic core material is replaced by a colloidal silica dispersion (total amount of silica: 1 g) having an average particle diameter of 100 nm. And the electroconductive particle 3 which formed the nickel film in the surface of this was produced. Furthermore, using the obtained conductive particles 2, insulating coated conductive particles 3 were obtained in the same manner as in Example 1, except that a colloidal silica dispersion having a diameter of 150 nm was used as the insulating fine particles. An anisotropic conductive adhesive film and a connected structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 3.

(Example 4)
Preparation of mother particles having silica particles adsorbed on the surface in the same manner as in Example 1 except that the nonconductive inorganic core material is replaced by a colloidal silica dispersion (total amount of silica: 1 g) having an average particle diameter of 150 nm. And the electroconductive particle 4 which formed the nickel film in the surface of this was produced. Furthermore, using the obtained conductive particles 4, insulating coated conductive particles 4 were obtained in the same manner as in Example 1 except that a colloidal silica dispersion having a diameter of 200 nm was used as the insulating fine particles. An anisotropic conductive adhesive film and a connected structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 4.

(Example 5)
Preparation of mother particles in which silica particles were adsorbed on the surface in the same manner as in Example 1 except that the nonconductive inorganic core material was changed to a colloidal silica dispersion (total amount of silica: 1 g) having an average particle diameter of 200 nm. And the electroconductive particle 5 in which the nickel film was formed on the surface of this was produced. Furthermore, using the obtained conductive particles 5, insulating coated conductive particles 5 were obtained in the same manner as in Example 1 except that a colloidal silica dispersion having a diameter of 300 nm was used as the insulating fine particles. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 5.

(Example 6)
Preparation of mother particles in which silica particles were adsorbed on the surface in the same manner as in Example 1 except that the nonconductive inorganic core material was replaced by a colloidal silica dispersion (total amount of silica: 1 g) having an average particle diameter of 600 nm. And the electroconductive particle 6 in which the nickel film was formed on the surface of this was produced. Furthermore, using the obtained conductive particles 5, insulating coated conductive particles 6 were obtained in the same manner as in Example 1 except that a colloidal silica dispersion having a diameter of 700 nm was used as the insulating fine particles. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 6.

(Example 7)
Production of mother particles in which silica particles are adsorbed on the surface, in the same manner as in Example 3, except that the concentration of the dispersion liquid of colloidal silica which is a nonconductive inorganic core material is changed to 0.12 mass% The conductive particles 7 having a nickel film formed on the surface of the above were produced. Furthermore, the insulation coating electrically conductive particle 7 was produced in the procedure similar to Example 1, and anisotropic conductive adhesive film and connection structure sample were produced.

(Example 8)
Production of mother particles in which silica particles are adsorbed on the surface in the same manner as in Example 3 except that the dispersion liquid concentration of colloidal silica which is a nonconductive inorganic core material is changed to 0.18 mass%, and The conductive particle 8 having a nickel film formed on its surface was produced. Furthermore, the insulation coating electrically conductive particle 8 was produced in the procedure similar to Example 1, and anisotropic conductive adhesive film and connection structure sample were produced.

(Example 9)
Production of mother particles in which silica particles are adsorbed on the surface, in the same manner as in Example 3, except that the concentration of the dispersion liquid of colloidal silica which is a nonconductive inorganic core material is changed to 0.25 mass% The conductive particle 9 having a nickel film formed on the surface of the above was prepared. Furthermore, the insulation coating electrically conductive particle 9 was produced in the procedure similar to Example 1, and anisotropic conductive adhesive film and connection structure sample were produced.

(Example 10)
Production of mother particles in which silica particles are adsorbed on the surface, in the same manner as in Example 3, except that the concentration of the dispersion liquid of colloidal silica, which is a nonconductive inorganic core material, was changed to 0.30 mass% The conductive particle 10 in which the nickel film was formed on the surface of was produced. Furthermore, the insulation coating electrically conductive particle 10 was produced in the procedure similar to Example 1, and anisotropic conductive adhesive film and connection structure sample were produced.

(Example 11)
Production of mother particles in which silica particles are adsorbed on the surface in the same manner as in Example 3 except that the concentration of the dispersion liquid of colloidal silica which is a nonconductive inorganic core material is changed to 0.42% by mass The conductive particle 11 in which the nickel film was formed on the surface of was produced. Furthermore, the insulation coating electrically conductive particle 11 was produced in the procedure similar to Example 1, and anisotropic conductive adhesive film and connection structure sample were produced.

(Example 12)
Zirconia particles were adsorbed on the surface in the same manner as in Example 1 except that a non-conductive inorganic core material was replaced by a zirconia (ZrO ₂ ) dispersion (total amount of zirconia: 2.7 g) having an average particle diameter of 100 nm. Preparation of mother particles and preparation of conductive particles 12 having a nickel film formed on the surface of the mother particles were performed. Furthermore, using the obtained conductive particles 12, insulating coated conductive particles 12 were obtained by the same procedure as in Example 1 except that a colloidal silica dispersion having a diameter of 150 nm was used as the insulating fine particles. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 12.

(Example 13)
Zirconia particles were formed on the surface in the same manner as in Example 1 except that an alumina (Al ₂ O ₃ ) dispersion (average amount of alumina: 1.8 g) having an average particle diameter of 100 nm was used as the nonconductive inorganic core material. Preparation of adsorbed base particles and preparation of conductive particles 13 having a nickel film formed on the surface thereof were performed. Furthermore, using the obtained conductive particles 13, insulating coated conductive particles 13 were obtained in the same manner as in Example 1 except that a colloidal silica dispersion having a diameter of 150 nm was used as the insulating fine particles. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 13.

(Example 14)
Titanium oxide particles on the surface in the same manner as in Example 1 except that titanium oxide (TiO ₂ ) dispersion liquid (total amount of titanium oxide: 1.9 g) having an average particle diameter of 100 nm was used as the nonconductive inorganic core material The production of the base particles on which the carbon black was adsorbed, and the production of the conductive particles 14 having a nickel film formed on the surface thereof, were carried out. Furthermore, using the obtained conductive particles 14, insulating coated conductive particles 14 were obtained by the same procedure as in Example 1 except that a colloidal silica dispersion having a diameter of 150 nm was used as the insulating fine particles. The anisotropic conductive adhesive film and the connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 14.

(Example 15)
In the same manner as in Example 1 except that the non-conductive inorganic core material was replaced by a diamond (C) dispersion (average amount of diamond: 1.6 g) having an average particle diameter of 100 nm, The production of particles and the production of conductive particles 15 having a nickel film formed on the surface thereof were carried out. Furthermore, using the obtained conductive particles 15, insulating coated conductive particles 15 were obtained by the same procedure as in Example 1 except that a colloidal silica dispersion having a diameter of 150 nm was used as the insulating fine particles. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 15.

(Example 16)
6.66 g of silica particles having an average particle diameter of 5.0 μm (Finesphere SK-50, trade name, manufactured by Nippon Electric Glass Co., Ltd.) is used as the nonconductive inorganic particles, and the average as the nonconductive inorganic core material is Silica particles are adsorbed on the surface in the same manner as in Example 1 except that colloidal silica dispersion of 70 nm in particle diameter (total amount of silica: 1 g) is used and 150 mL of first layer electroless nickel plating solution is dropped. Preparation of base particles and conductive particles 16 having a nickel film formed on the surface of the base particles were carried out. Furthermore, using the obtained conductive particles 16, insulating coated conductive particles 16 were obtained in the same manner as in Example 1 except that a colloidal silica dispersion having a diameter of 150 nm was used as the insulating fine particles. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 16.

(Example 17)
6.66 g of silica particles having an average particle diameter of 5.0 μm (Finesphere SK-50, trade name, manufactured by Nippon Electric Glass Co., Ltd.) is used as the nonconductive inorganic particles, and the average as the nonconductive inorganic core material is Silica particles were adsorbed on the surface in the same manner as in Example 1 except that 150 mL of the first layer electroless nickel plating solution was dropped using colloidal silica dispersion (total amount of silica: 1 g) having a particle diameter of 150 nm. Preparation of the base particle which carried out, and preparation of the electrically-conductive particle 17 in which the nickel film was formed on the surface of this were performed. Furthermore, using the obtained conductive particles 16, insulating coated conductive particles 17 were obtained in the same manner as in Example 1, except that a colloidal silica dispersion having a diameter of 300 nm was used as the insulating fine particles. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 17.

(Example 18)
6.66 g of silica particles having an average particle diameter of 5.0 μm (Finesphere SK-50, trade name, manufactured by Nippon Electric Glass Co., Ltd.) is used as the nonconductive inorganic particles, and the average as the nonconductive inorganic core material is Silica particles were adsorbed on the surface in the same manner as in Example 1 except that 150 mL of the first layer electroless nickel plating solution was dropped using colloidal silica dispersion (total amount of silica: 1 g) with a particle diameter of 450 nm. Preparation of base particles and conductive particles 18 having a nickel film formed on the surface of the base particles were carried out. Furthermore, using the obtained conductive particles 18, insulating coated conductive particles 18 were obtained by the same procedure as in Example 1 except that a colloidal silica dispersion having a diameter of 600 nm was used as the insulating fine particles. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 18.

(Example 19)
6.66 g of silica particles having an average particle diameter of 5.0 μm (Finesphere SK-50, trade name, manufactured by Nippon Electric Glass Co., Ltd.) is used as the nonconductive inorganic particles, and the average as the nonconductive inorganic core material is Silica particles were adsorbed on the surface in the same manner as in Example 1 except that 150 mL of the first layer electroless nickel plating solution was dropped using colloidal silica dispersion (total amount of silica: 1 g) having a particle diameter of 1000 nm. Preparation of base particles and conductive particles 19 having a nickel film formed on the surface of the base particles were carried out. Furthermore, using the obtained conductive particles 19, insulating coated conductive particles 19 were obtained in the same manner as in Example 1 except that a colloidal silica dispersion with a diameter of 1300 nm was used as the insulating fine particles. An anisotropic conductive adhesive film and a connected structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 19.

Example 20
13.35 g of silica particles with an average particle diameter of 10.0 μm (Finesphere SK-100, trade name, manufactured by Nippon Electric Glass Co., Ltd.) are used as the nonconductive inorganic particles, and the average as the nonconductive inorganic core material Silica particles were adsorbed on the surface in the same manner as in Example 1 except that 300 mL of the first layer electroless nickel plating solution was dropped using colloidal silica dispersion (total amount of silica: 1 g) having a particle diameter of 100 nm. Preparation of the base particle which carried out, and preparation of the electrically-conductive particle 20 which formed the nickel film in the surface of this were performed. Furthermore, using the obtained conductive particles 20, insulating coated conductive particles 20 were obtained in the same manner as in Example 1 except that a colloidal silica dispersion having a diameter of 200 nm was used as the insulating fine particles. An anisotropic conductive adhesive film and a connected structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 20.

(Example 21)
13.35 g of silica particles with an average particle diameter of 10.0 μm (Finesphere SK-100, trade name, manufactured by Nippon Electric Glass Co., Ltd.) are used as the nonconductive inorganic particles, and the average as the nonconductive inorganic core material Silica particles were adsorbed on the surface in the same manner as in Example 1 except that 300 mL of the first layer electroless nickel plating solution was dropped using colloidal silica dispersion (total amount of silica: 1 g) having a particle diameter of 450 nm. Preparation of the base particle which carried out, and preparation of the electrically-conductive particle 20 which formed the nickel film in the surface of this were performed. Furthermore, using the obtained conductive particles 21, insulating coated conductive particles 21 were obtained in the same manner as in Example 1 except that a colloidal silica dispersion having a diameter of 600 nm was used as the insulating fine particles. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 21.

(Example 22)
13.35 g of silica particles with an average particle diameter of 10.0 μm (Finesphere SK-100, trade name, manufactured by Nippon Electric Glass Co., Ltd.) are used as the nonconductive inorganic particles, and the average as the nonconductive inorganic core material Silica particles were adsorbed on the surface in the same manner as in Example 1 except that 300 mL of the first layer electroless nickel plating solution was dropped using colloidal silica dispersion (total amount of silica: 1 g) having a particle diameter of 1000 nm. Preparation of base particles and conductive particles 22 having a nickel film formed on the surface of the base particles were carried out. Furthermore, using the obtained conductive particles 22, insulating coated conductive particles 22 were obtained in the same manner as in Example 1 except that a colloidal silica dispersion having a diameter of 1300 nm was used as insulating fine particles. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 22.

(Example 23)
13.35 g of silica particles with an average particle diameter of 10.0 μm (Finesphere SK-100, trade name, manufactured by Nippon Electric Glass Co., Ltd.) are used as the nonconductive inorganic particles, and the average as the nonconductive inorganic core material Silica particles were adsorbed on the surface in the same manner as in Example 1 except that 300 mL of the first layer electroless nickel plating solution was dropped using colloidal silica dispersion (total amount of silica: 1 g) with a particle diameter of 2000 nm. Preparation of the base particle which carried out, and preparation of the electrically-conductive particle 23 which formed the nickel film in the surface of this were performed. Furthermore, using the obtained conductive particles 23, insulating coated conductive particles 23 were obtained in the same manner as in Example 1 except that a colloidal silica dispersion having a diameter of 2500 nm was used as the insulating fine particles. The anisotropic conductive adhesive film and the connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 23.

(Comparative example 1)
Comparative conductive particles 1 in which a nickel film was formed on the surface of nonconductive inorganic particles in the same manner as in Example 1 except that the nonconductive inorganic core material was not used, were produced. Furthermore, comparative insulation coated conductive particles 1 were produced in the same manner as in Example 1, and anisotropic conductive adhesive films and connection structure samples were produced.

(Comparative example 2)
Acrylic fine particles are adsorbed on the surface by the same procedure as in Example 1 except that an acrylic fine particle dispersion having an average particle diameter of 100 nm and a CV of 2.8% is used instead of the nonconductive inorganic core material. Preparation of base particles was carried out, and comparison conductive particles 2 in which a nickel film was formed on the surface of the base particles were prepared. Furthermore, comparative insulation coated conductive particles 2 were produced in the same manner as in Example 1, and anisotropic conductive adhesive films and bonded structure samples were produced.

(Comparative example 3)
Preparation of mother particles having Ni fine particles adsorbed on the surface by the same procedure as in Example 1 except that a Ni fine particle dispersion having an average particle diameter of 100 nm was used instead of the nonconductive inorganic core material, and this Comparative conductive particles 2 in which a nickel film was formed on the surface of the above were produced. Furthermore, comparative insulation coated conductive particles 3 were produced in the same manner as in Example 1, and anisotropic conductive adhesive films and bonded structure samples were produced.

(Comparative example 4)
Production of mother particles in which silica particles are adsorbed on the surface, and in the same manner as in Example 1 except that acrylic particles having an average particle diameter of 3.0 μm are used instead of nonconductive inorganic particles Comparative conductive particles 4 having a nickel film formed thereon were produced. Furthermore, comparative insulation coated conductive particles 4 were produced in the same manner as in Example 1, and anisotropic conductive adhesive films and bonded structure samples were produced.

(Comparative example 5)
In the same manner as in Example 1 except that Ni particles having an average particle diameter of 3.0 μm were used instead of nonconductive inorganic particles, preparation of mother particles in which silica particles were adsorbed on the surface, and on the surface thereof Comparative conductive particles 5 having a nickel film formed thereon were produced. Furthermore, comparative insulation coated conductive particles 5 were produced in the same manner as in Example 1, and anisotropic conductive adhesive films and bonded structure samples were produced.

(Evaluation of coverage and coverage variation)
100 sheets of SEM images of mother core (composite particles) with non-conductive inorganic core material or core material instead of non-conductive inorganic core material adsorbed on the surface are prepared, and coverage with silica particles and coating by image analysis of center part of mother particles The variation was measured. For image analysis, a circle range of 1/2 of the diameter of the nonconductive inorganic particles was used. When the diameter of the nonconductive inorganic particles is 3.0 μm, a circle of 1.5 μm in diameter, in the case of 5.0 μm, a circle of 2.5 μm in diameter, and in the case of 10.0 μm, a circle of 5.0 μm in diameter . The coating variation (C.V.) was calculated by the standard deviation of the coverage / average coverage. The results are shown in Table 1 together with the configuration of each conductive particle.

(Insulation resistance test and conduction resistance test)
The insulation resistance test and the conduction resistance test of the samples produced in each example and comparative example were conducted. It is important that the anisotropic conductive adhesive film has high insulation resistance between tip electrodes and low conduction resistance between tip electrodes / glass electrodes. The insulation resistance between tip electrodes measured ten samples. The insulation resistance was subjected to an initial value and a migration test (air temperature 60 ° C., relative humidity 90%, 20 V applied) for 1000 hours) to calculate the yield when the insulation resistance> 10 ⁹ (Ω) was good. Moreover, regarding the conduction resistance between the tip electrode / glass electrode, the average value of 14 samples was measured. The conduction resistance was measured at the initial value and the value after the hygroscopic heat resistance test (standing at a temperature of 85 ° C. and a relative humidity of 85% for 1000 hours).
(Impression) It was judged whether or not a crushed trace of particles remained on the electrode on the glass substrate side after mounting. The indentation is judged by whether or not the electrode portion can be dented in order to confirm particle trapping. If the particles are too soft there may be no impression. In this case, the inspection of conductivity becomes practically difficult.

(Plating peeling)
It was judged that there was plating peeling when plating peeling occurred in 10% or more of the conductive particles.

The measurement results are shown in Table 1. Both examples achieved lower initial conduction resistance as compared to the comparative example. This is considered to be due to the fact that the conductivity is increased by the projections sticking into the hard Ti layer when the hard silica particles press the plating layer having the projection shape against the Ti—Al—Ti electrode. The Ti layer has its surface oxidized and has a hard oxide film (TiO ₂ ), and it is difficult to obtain stable connection resistance, but in this example, a silica core material is disposed on the surface of hard silica particles. Therefore, it is considered that the conductive layer was embedded in the protrusion portion formed of the silica core material without pushing the oxide layer of Ti. In Examples 2, 3, 4, 5, 16, 17, 18, 21, and 22, particularly, the connection resistance was stable even after the high temperature and high humidity test. In other words, the connection resistance was particularly good when the ratio of the diameter of the particles to the diameter of the core material particles disposed on the surface of the particles was approximately 2 to 10. In Comparative Example 1, since there is no nonconductive inorganic core material, there is no protrusion on the Ni plating surface, the resin removability between the plating layer and the electrode is poor, and the plating layer does not bite into the electrode sufficiently. And the connection resistance was bad. In Comparative Examples 2 and 3, since the core material is disposed on the surface of the silica particles, protrusions are formed on the plating layer, but the core material is made of acrylic which is softer than the plating layer or nickel of the same material as the plating layer. As a result, when the projections were inserted between the electrode and the silica particle, the core material was crushed, indicating that the plating layer could not be sufficiently embedded in the electrode. Further, in Comparative Examples 4 and 5, since the acrylic particles and the nickel particles that are softer than the silica core material are used, the silica core material is returned to the acrylic particles and the nickel particles, and the connection resistance is inferior to that of the example. In particular, in Comparative Example 5, since the particle size distribution is wide (C.V. poor), the insulation reliability is also significantly inferior.

Next, the effects of different plated layers will be described with an example.
(Example 24)
A plating solution was prepared by adding 9 g of tetrachloropalladium, 10 g of ethylene diamine, 5 g of aminopyridine, 18 g of sodium hypophosphite, and 20 g of polyethylene glycol to 1 L of ultrapure water. Using this plating solution, the conductive particles 3 produced in Example 3 were successively subjected to palladium plating treatment under conditions of pH 7.5 and liquid temperature 60 ° C. until the thickness became 20 nm on average. After filtration, the conductive particles 24 were washed with 100 mL of pure water for 60 seconds to produce conductive particles 24 having a 20 nm-thick palladium plating film formed on the outside of the nickel film. Furthermore, insulation coated conductive particles 24 were obtained using the obtained conductive particles 24 in the same manner as in Example 3. An anisotropic conductive adhesive film and a connected structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 24.

(Example 25)
A plating solution containing 0.03 mol / L tetrasodium ethylenediaminetetraacetate, 0.04 mol / L trisodium citrate and 0.01 mol / L potassium potassium cyanide and adjusted to pH 6 with sodium hydroxide was prepared. . Using this plating solution, the conductive particles 3 produced in Example 3 were subsequently subjected to a gold plating treatment under the conditions of a solution temperature of 60 ° C. until the average thickness became 20 nm. After filtration, the resultant was washed with 100 mL of pure water for 60 seconds to produce conductive particles 25 having a 20 nm-thick gold film formed on the outside of the nickel film. Furthermore, insulation coated conductive particles 25 were obtained using the obtained conductive particles 25 in the same manner as in Example 3. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 25.

(Example 26)
A plating solution containing 0.03 mol / L tetrasodium ethylenediaminetetraacetate, 0.04 mol / L trisodium citrate and 0.01 mol / L potassium potassium cyanide and adjusted to pH 6 with sodium hydroxide was prepared. . Using this plating solution, the conductive particles 24 produced in Example 24 were subsequently subjected to gold plating treatment at a solution temperature of 60 ° C. until the thickness became 20 nm on average. After filtration, the resultant was washed with 100 mL of pure water for 60 seconds to produce conductive particles 26 having a 20 nm-thick gold film formed on the outside of the palladium film. Furthermore, insulation coated conductive particles 26 were obtained using the obtained conductive particles 26 in the same manner as in Example 3. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 26.

(Example 27)
In the same manner as in Example 24 except that the conductive particles 12 were used, conductive particles 27 having a palladium plating film with a thickness of 20 nm on the outside of the nickel film were produced. Furthermore, insulation coated conductive particles 27 were obtained in the same manner as in Example 3 using the obtained conductive particles 27. An anisotropic conductive adhesive film and a connected structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 27.

(Example 28)
A conductive particle 28 having a gold-plated film with a thickness of 20 nm on the outside of the nickel film was produced in the same manner as in Example 25 except that the conductive particle 12 was replaced. Furthermore, insulation coated conductive particles 28 were obtained using the obtained conductive particles 28 in the same manner as in Example 3. An anisotropic conductive adhesive film and a connected structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 28.

(Example 29)
In the same manner as in Example 26 except that the conductive particles 27 were replaced, a conductive particle 29 having a palladium plating film with a thickness of 20 nm on the outside of the nickel film and a gold plating film with a thickness of 20 nm on the outside of the palladium plating film Made. Furthermore, insulation coated conductive particles 29 were obtained using the obtained conductive particles 29 in the same manner as in Example 3. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 29.

(Example 30)
A conductive particle 30 having a palladium plating film with a thickness of 20 nm on the outside of the nickel film was produced in the same manner as in Example 24 except that the conductive particle 13 was replaced. Furthermore, insulation coated conductive particles 30 were obtained using the obtained conductive particles 30 in the same manner as in Example 3. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 30.

(Example 31)
A conductive particle 31 having a gold-plated film with a thickness of 20 nm outside the nickel film was produced in the same manner as in Example 25 except that the conductive particle 13 was replaced. Furthermore, insulation coated conductive particles 31 were obtained in the same manner as in Example 3 using the obtained conductive particles 31. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 31.

(Example 32)
In the same manner as in Example 26 except that conductive particles 30 were replaced, conductive particles 32 having a palladium plating film with a thickness of 20 nm on the outside of a nickel film and a gold plating film with a thickness of 20 nm on the outside of a palladium plating film Made. Furthermore, insulation coated conductive particles 32 were obtained using the obtained conductive particles 32 in the same manner as in Example 3. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 32.

(Example 33)
In the same manner as in Example 24 except that the conductive particles 14 were replaced, conductive particles 33 having a palladium plating film with a thickness of 20 nm on the outside of the nickel film were produced. Furthermore, using the obtained conductive particles 33, insulating coated conductive particles 33 were obtained in the same manner as in Example 3. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 33.

(Example 34)
A conductive particle 34 having a gold plating film with a thickness of 20 nm outside the nickel film was produced in the same manner as in Example 25 except that the conductive particle 14 was replaced. Furthermore, insulation coated conductive particles 34 were obtained in the same manner as in Example 3 using the obtained conductive particles 34. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 34.

(Example 35)
In the same manner as in Example 26 except that conductive particles 33 were replaced, conductive particles 35 having a palladium plating film with a thickness of 20 nm on the outside of the nickel film and a gold plating film with a thickness of 20 nm on the outside of the palladium plating film Made. Furthermore, using the obtained conductive particles 35, insulating coated conductive particles 35 were obtained in the same procedure as in Example 3. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 35.

(Example 36)
In the same manner as in Example 24 except that the conductive particles 15 were replaced, conductive particles 36 having a palladium plating film with a thickness of 20 nm on the outside of the nickel film were produced. Furthermore, using the obtained conductive particles 36, insulating coated conductive particles 36 were obtained in the same manner as in Example 3. An anisotropic conductive adhesive film and a connected structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 36.

(Example 37)
A conductive particle 37 having a gold plating film with a thickness of 20 nm outside the nickel film was produced in the same manner as in Example 25 except that the conductive particle 15 was replaced. Furthermore, insulation coated conductive particles 37 were obtained using the obtained conductive particles 37 in the same procedure as in Example 3. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 37.

(Example 38)
In the same manner as in Example 26 except that the conductive particles 36 were replaced, conductive particles 38 having a 20 nm-thick palladium plating film on the outside of the nickel film and a 20 nm-thick gold plating film on the outside of the palladium plating film Made. Furthermore, using the obtained conductive particles 38, insulating coated conductive particles 38 were obtained in the same manner as in Example 3. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 38.

(Example 39)
In the same manner as in Example 24 except that the conductive particles 18 were used, conductive particles 39 having a palladium plating film with a thickness of 20 nm on the outside of the nickel film were produced. Furthermore, using the obtained conductive particles 39, insulating coated conductive particles 39 were obtained in the same manner as in Example 3. An anisotropic conductive adhesive film and a connected structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 39.

(Example 40)
A conductive particle 40 having a gold-plated film with a thickness of 20 nm on the outside of the nickel film was produced in the same manner as in Example 25 except that the conductive particle 18 was replaced. Furthermore, insulation coated conductive particles 40 were obtained in the same manner as in Example 3 using the obtained conductive particles 40. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 40.

(Example 41)
In the same manner as in Example 26 except that the conductive particles 39 were replaced, a conductive particle 41 having a palladium plating film with a thickness of 20 nm on the outside of the nickel film and a gold plating film with a thickness of 20 nm on the outside of the palladium plating film Made. Furthermore, insulation coated conductive particles 41 were obtained in the same manner as in Example 3 using the obtained conductive particles 41. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 41.

(Example 42)
In the same manner as in Example 24 except that the conductive particles 22 were replaced, conductive particles 42 having a palladium plating film with a thickness of 20 nm on the outside of the nickel film were produced. Furthermore, insulation coated conductive particles 42 were obtained using the obtained conductive particles 42 in the same manner as in Example 3. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 42.

(Example 43)
A conductive particle 43 having a gold-plated film with a thickness of 20 nm on the outside of the nickel film was produced in the same manner as in Example 25 except that the conductive particle 22 was replaced. Furthermore, insulation coated conductive particles 43 were obtained using the obtained conductive particles 43 in the same manner as in Example 3. An anisotropic conductive adhesive film and a connected structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 43.

(Example 44)
In the same manner as in Example 26 except that the conductive particles 42 were replaced, a conductive particle 44 having a palladium plating film with a thickness of 20 nm on the outside of the nickel film and a gold plating film with a thickness of 20 nm on the outside of the palladium plating film Made. Furthermore, using the obtained conductive particles 44, insulating coated conductive particles 44 were obtained in the same manner as in Example 3. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 44.
The evaluation results are shown in Table 2.

  When the gold plating layer was provided outside the nickel layer, the connection resistance was lower than that of the nickel layer alone, and when the palladium plating layer was provided outside the nickel layer, the insulation was improved more than the nickel layer alone. . Furthermore, when the palladium plating layer was provided on the outside of the nickel layer and the gold plating layer was provided on the outside of the palladium plating layer, it was confirmed that the connection resistance was reduced and the insulation was improved.

(Example 45)
Using the method of Example 3, mother particles 3 in which a silica inorganic core material having an average particle diameter of 100 nm was disposed on the surface of silica inorganic particles having an average particle diameter of 3.0 μm were obtained.
After irradiating an ultrasonic wave with a resonance frequency of 28 kHz and an output of 100 W for 15 minutes to 4 g of the mother particles (mother particles 3), 8 mass of Atotech Neneoganto 834 (Atotech Japan Co., Ltd .: trade name) which is a palladium catalyst The solution was added to 100 mL of a palladium catalyst solution containing 10% and stirred at 30 ° C. for 30 minutes while being irradiated with ultrasonic waves. Thereafter, the base particles were taken out by filtration using a membrane filter (made by Millipore) having a diameter of 3 μm, and the taken out base particles were washed with water. The washed mother particles were added to a 0.5 mass% dimethylamine borane solution adjusted to pH 6.0 to obtain surface-activated mother particles.

Thereafter, mother particles 3 are added to a 2 L construction bath solution having the following composition heated to 40 ° C., and a first portion containing 97 mass% or more of nickel, and nickel and copper as main components Form a second part containing the alloy. Further, 930 mL of each of nickel-free replenisher A and replenisher B having the following composition were prepared by the addition method, and continuously dropped at a rate of 20 mL / min to form a third portion mainly composed of copper .
(Building solution)
CuSO ₄ · 5H ₂ O: 0.03 mol / L
NiSO ₄ · 6H ₂ O: 0.005 mol / L
HCHO (formaldehyde): 0.2 mol / L
NaCN: 0.0001 mol / L
EDTA · 4Na: 0.2 mol / L
NaOH: 0.3 mol / L
pH: 12.7
(Refillment solution A)
CuSO ₄ · 5 H ₂ O: 0.8 mol / L
HCHO: 1 mol / L
NaCN: 0.001 mol / L
(Refilling solution B)
EDTA · 4Na: 1 mol / L
NaOH: 1 mol / L

Subsequently, 100 mL of a palladium catalyzed solution containing 8% by mass of Atotech Neneoganto 834 (trade name, manufactured by Atotech Japan Co., Ltd.), which is a palladium catalyst, is added and stirred at 30 ° C. for 30 minutes. It filtered with a filter (made by Millipore, Inc.) and washed with water. Thereafter, the particles were added to a 0.5 mass% dimethylamine borane solution adjusted to pH 6.0 to activate the surface of the particles. Thereafter, the particles whose surface was activated were immersed in 20 mL of distilled water and ultrasonically dispersed to obtain a particle dispersion.
Subsequently, it was dispersed in 1000 mL of water heated to 70 ° C. 1 mL of a 1 g / L aqueous solution of bismuth nitrate as a plating stabilizer was added to this dispersion, and then 50 mL of a fourth partial formation electroless nickel plating solution having the following composition was dropped at a dropping rate of 5 mL / min. After 10 minutes had passed after completion of the dropwise addition, the dispersion to which the plating solution had been added was filtered, and the filtrate was washed with water and then dried with a vacuum dryer at 80 ° C. Thus, conductive particles 45 having a fourth portion composed of a 40 nm-thick nickel-phosphorus alloy film shown in Table 3 were obtained. The obtained conductive particles 45 were 8 g.
[The fourth part formation electroless nickel plating solution]
Nickel sulfate ················ 400g / L
Sodium hypophosphite ........... 150 g / L
Sodium tartrate dihydrate ..... 120g / L
Bismuth nitrate aqueous solution (1 g / L) ..... 1 mL / L

Thereafter, in the same manner as in Example 3, preparation of insulating coated particles, preparation of anisotropic conductive adhesive film and connection structure, and evaluation of connection structure were performed.
(Examples 46 to 51)
In the same manner as in Examples 12 to 15, 18 and 22, mother particles 12 to 15, mother particles 18 and mother particles 22 were obtained. In the same manner as in Example 45, conductive particles 46 to 51 were obtained in which the metal plating layer was formed on the surface of the base particles.
Thereafter, in the same manner as in Examples 12 to 15, Example 18, and Example 22, preparation of insulating coated particles, preparation of anisotropic conductive adhesive film and connected structure, and evaluation of connected structure were performed.

(Comparative example 6)
The amount of the plating solution was adjusted to the thickness of the first layer shown in Table 3 by the same procedure as in Example 45 except that the nonconductive inorganic core material was not used, and the nonconductive inorganic material was used. Comparative conductive particles 6 were produced in which a plating film containing nickel and copper as main components was formed on the surface of the particles. Furthermore, comparative insulation coated conductive particles 6 were produced in the same manner as in Example 1, and anisotropic conductive adhesive films and bonded structure samples were produced.

(Comparative Examples 7 to 10)
Comparative mother particles 2 to 5 were obtained in the same manner as in Comparative Examples 2 to 5, respectively. Comparative conductive particles 2 to 5 were obtained in the same manner as in Example 45, except that plating films containing nickel and copper as main components were formed on the surface of the base particles.

Thereafter, in the same manner as in Example 45, preparation of insulating coated particles, preparation of anisotropic conductive adhesive film and connected structure, and evaluation of connected structure were carried out.
The measurement results are shown in Table 3.

  All Examples 45-51 achieved low initial conduction resistance as compared to Comparative Examples 6-10. By making the plating layer mainly composed of nickel and copper, the connection resistance is further lowered than that of the nickel layer alone. Even in the case where the plating layer contains copper having a hardness lower than that of nickel, the plating layer is strongly pressed against the electrode and the plating layer is embedded in the electrode by using a material whose particles and core are harder than the plating layer. It can be considered that stable connection resistance was obtained because it can not be done. In Comparative Example 6, although the initial resistance was slightly improved compared to Comparative Example 1, the resistance was deteriorated after the moisture absorption test. This is considered to be because, although Comparative Example 6 contains copper having a resistance lower than that of nickel in the plating layer, the plating layer does not sufficiently bite into a hard electrode because it does not have a protrusion shape.

(Example 52)
A plating solution was prepared by adding 9 g of tetrachloropalladium, 10 g of ethylene diamine, 5 g of aminopyridine, 18 g of sodium hypophosphite, and 20 g of polyethylene glycol to 1 L of ultrapure water. Using this plating solution, the conductive particles 45 produced in Example 45 were successively subjected to palladium plating treatment under conditions of pH 7.5, solution temperature 60 ° C. until the thickness became 20 nm on average. After filtration, the conductive particles 52 were washed with 100 mL of pure water for 60 seconds to produce a 20 nm-thick palladium-plated film formed on the outside of the nickel film. Furthermore, insulation coated conductive particles 52 were obtained in the same manner as in Example 3 using the obtained conductive particles 52. An anisotropic conductive adhesive film and a connected structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 52.

(Example 53)
A plating solution containing 0.03 mol / L tetrasodium ethylenediaminetetraacetate, 0.04 mol / L trisodium citrate and 0.01 mol / L potassium potassium cyanide and adjusted to pH 6 with sodium hydroxide was prepared. . Using this plating solution, the conductive particles 45 produced in Example 45 were successively subjected to gold plating treatment at a solution temperature of 60 ° C. until the thickness became 20 nm on average. After filtration, the resultant was washed with 100 mL of pure water for 60 seconds to produce conductive particles 53 having a gold film with a thickness of 20 nm formed on the outside of the nickel film. Furthermore, using the obtained conductive particles 53, insulating coated conductive particles 53 were obtained in the same manner as in Example 3. An anisotropic conductive adhesive film and a connection structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 53.

(Example 54)
A plating solution containing 0.03 mol / L tetrasodium ethylenediaminetetraacetate, 0.04 mol / L trisodium citrate and 0.01 mol / L potassium potassium cyanide and adjusted to pH 6 with sodium hydroxide was prepared. . Using this plating solution, the conductive particles 52 produced in Example 52 were successively subjected to gold plating treatment at a solution temperature of 60 ° C. until the thickness became 20 nm on average. After filtration, the resultant was washed with 100 mL of pure water for 60 seconds to produce conductive particles 54 having a gold film with a thickness of 20 nm formed on the outside of the palladium film. Furthermore, insulation coated conductive particles 54 were obtained in the same manner as in Example 3 using the obtained conductive particles 54. An anisotropic conductive adhesive film and a connected structure sample were produced in the same manner as in Example 1 using the obtained insulating coated conductive particles 54.

(Example 55)
In the same manner as in Example 52, except that the conductive particles 45 were used instead of the conductive particles 45, production of the conductive particles 55, production of the insulating coated conductive particles 55, production of an anisotropic conductive adhesive film and a connection structure sample Did.

(Example 56)
In the same manner as in Example 53, except that the conductive particles 45 are used instead of the conductive particles 45, production of the conductive particles 56, production of the insulating coated conductive particles 56, production of an anisotropic conductive adhesive film and a connection structure sample Did.

(Example 57)
In the same manner as in Example 54, except that the conductive particles 52 were used instead of the conductive particles 52, production of conductive particles 57, production of insulating coated conductive particles 57, production of anisotropic conductive adhesive film and connection structure sample Did.

(Example 58)
In the same manner as in Example 52 except that the conductive particles 45 were used instead of the conductive particles 45, production of conductive particles 58, production of insulating coated conductive particles 58, production of anisotropic conductive adhesive film and connection structure sample Did.

(Example 59)
In the same manner as in Example 53, except that the conductive particles 45 were used instead of the conductive particles 45, production of conductive particles 59, production of insulating coated conductive particles 59, production of anisotropic conductive adhesive film and connection structure sample Did.

(Example 60)
In the same manner as in Example 54, except that the conductive particles 52 were used instead of the conductive particles 52, production of the conductive particles 60, production of the insulating coated conductive particles 60, production of an anisotropic conductive adhesive film and a connection structure sample Did.

(Example 61)
In the same manner as in Example 52 except that the conductive particles 45 were used instead of the conductive particles 45, production of the conductive particles 60, production of the insulating coated conductive particles 60, production of an anisotropic conductive adhesive film and a connection structure sample Did.

(Example 62)
In the same manner as in Example 53, except that the conductive particles 45 were used instead of the conductive particles 45, production of the conductive particles 62, production of the insulating coated conductive particles 62, production of an anisotropic conductive adhesive film and a connection structure sample Did.

(Example 63)
In the same manner as in Example 54, except that the conductive particles 52 were used instead of the conductive particles 52, production of the conductive particles 63, production of the insulating coated conductive particles 63, production of an anisotropic conductive adhesive film and a connection structure sample Did.

(Example 64)
In the same manner as in Example 52 except that the conductive particles 45 were used instead of the conductive particles 45, production of the conductive particles 64, production of the insulating coated conductive particles 64, production of the anisotropic conductive adhesive film and the connection structure sample Did.

(Example 65)
In the same manner as in Example 53, except that the conductive particles 45 are used instead of the conductive particles 45, production of the conductive particles 65, production of the insulating coated conductive particles 65, production of an anisotropic conductive adhesive film and a connection structure sample Did.

(Example 66)
In the same manner as in Example 54, except that the conductive particles 52 were used instead of the conductive particles 52, production of conductive particles 66, production of insulating coated conductive particles 66, production of anisotropic conductive adhesive film and connection structure sample Did.

(Example 67)
In the same manner as in Example 52 except that the conductive particles 45 were used instead of the conductive particles 45, production of the conductive particles 67, production of the insulating coated conductive particles 67, production of an anisotropic conductive adhesive film and a connection structure sample Did.

(Example 68)
In the same manner as in Example 53, except that the conductive particles 45 were used instead of the conductive particles 45, production of the conductive particles 68, production of the insulating coated conductive particles 68, production of the anisotropic conductive adhesive film and the connection structure sample Did.

(Example 69)
In the same manner as in Example 54, except that the conductive particles 52 were used instead of the conductive particles 52, production of conductive particles 69, production of insulating coated conductive particles 69, production of anisotropic conductive adhesive film and connection structure sample Did.

(Example 70)
In the same manner as in Example 52, except that the conductive particles 45 were used instead of the conductive particles 45, production of the conductive particles 70, production of the insulating coated conductive particles 70, production of an anisotropic conductive adhesive film and a connection structure sample Did.

(Example 71)
In the same manner as in Example 53, except that the conductive particles 45 are used instead of the conductive particles 45, production of the conductive particles 71, production of the insulating coated conductive particles 71, production of an anisotropic conductive adhesive film and a connection structure sample Did.

(Example 72)
In the same manner as in Example 54, except that the conductive particles 52 were used instead of the conductive particles 52, production of the conductive particles 72, production of the insulating coated conductive particles 72, production of an anisotropic conductive adhesive film and a connection structure sample Did.
The measurement results are shown in Table 4.

  When a gold plating layer is provided on the outside of the layer mainly composed of nickel and copper, the connection resistance becomes lower than that of the layer mainly composed of nickel and copper and the layer mainly composed of nickel and copper When the palladium plating layer was provided outside, insulation improved rather than only the layer which has nickel and copper as a main component. Furthermore, when the palladium plating layer was provided on the outside of the layer mainly composed of nickel and copper and the gold plating layer was provided on the outside of the palladium plating layer, reduction in connection resistance and improvement in insulation were confirmed.

DESCRIPTION OF SYMBOLS 1 ... Conductive particle, 5 ... Mother particle, 20 ... Nonconductive inorganic particle, 30 ... Nonconductive inorganic core material, 35 ... Insulating fine particle, 40 ... Metal plating layer, 40a ... Projection part, 60 ... 1st Circuit member, 61: driver IC, 62: bump electrode, 70: second circuit member, 71: glass substrate, 72: electrode, 80: anisotropic conductive adhesive, 81: insulating adhesive.

Claims (7)

Mother particles having nonconductive inorganic particles and a nonconductive inorganic core material disposed on the surface of the nonconductive inorganic particles;
A metal plating layer covering the mother particles ;
And insulating fine particles partially covering the surface of the metal plating layer ,
The metal plating layer has a surface on which a protrusion is formed,
A conductive particle, wherein the nonconductive inorganic particle and the nonconductive inorganic core material are both harder than a metal plating layer. Conductive particles of claim 1 wherein the conductive particles constituting the non-conductive inorganic particles and non-conductive core material are both, characterized in that harder than the material constituting the thickest layer of the electrodes. The non-conductive inorganic particles and the non-conductive inorganic core material, the conductive particle according to claim 1 or 2 any more than 90 wt%, characterized in that a SiO _2.   The conductive particle according to any one of claims 1 to 3, wherein the metal plating layer contains any of nickel, copper, tin, palladium and gold.   The said metal plating layer is formed by electroless plating, The electrically-conductive particle as described in any one of Claims 1-4 characterized by the above-mentioned.   The projected long side a and the projected short side b of the nonconductive inorganic particle, and the projected long side c and the projected short side d of the nonconductive inorganic core material are a / b <3 and c / d <5 and a The conductive particle according to any one of claims 1 to 5, wherein ≧ 5c.   An anisotropic conductive adhesive comprising the conductive particle according to any one of claims 1 to 6.

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