KR20100088494A - Insulating conductive ball for anisotropic conductive film and fabrication method thereof - Google Patents

Abstract

PURPOSE: An insulating conductive particle for an anisotropic conductive film, and a manufacturing method thereof are provided to secure the dispersion stability of the conductive particle inside an anisotropically conductive adhesive resin. CONSTITUTION: An insulating conductive particle for an anisotropic conductive film includes insulating minute particles mechanochemically bonded to a conductive particle through a mechano-fusion. The conductive particle is a metal particle in which a metal selected from the group consisting of gold, silver, iron, copper, nickel, cadmium, bismuth, indium, aluminum, palladium, platinum, and chromium, is coated with a polymer particle selected from the group consisting of polystyrene, polymethacrylate, polymethylmethacrylate, polyvinylacetate, divinylbenzene, and benzoguanamine.

Description

Insulated conductive particle for anisotropic conductive film and manufacturing method therefor {INSULATING CONDUCTIVE BALL FOR ANISOTROPIC CONDUCTIVE FILM AND FABRICATION METHOD THEREOF}

The present invention relates to insulating conductive particles for anisotropic conductive films using a mechanochemical bonding system, and a method of manufacturing the same.

Flat Panel Display (FPD), such as LCD and PDP, has the advantages of thin, light weight and low power consumption. Therefore, application products have been developed and commercialized in various fields mainly on mobile products. Significant rationalization is required in process and process.

In order to meet the demands of the industry, the mounting method of the driver (LSI) in the FPD module has been shifted from the Quad Flat Package (QFP) method to the Tape Automated Bonding (TAB) method and the Chip On Glass (COG) method. The key element in the evolution of the method is the provision of an anisotropic conductive film (ACF), which can simultaneously propose the characteristics of securing conductivity and imparting adhesion.

The characteristics required for ACF as a connection material vary depending on the applied product group, but in COG mounting where bare chips are directly mounted on the LCD panel, conductive particles are required to achieve the minimum number of trapped particles per bump of the small area according to the micro-miniaturization of the connection pitch. It is very important to secure the insulation reliability in the XY direction according to the increase of the particle mixing density while improving the connection reliability by increasing the compounding amount of.

As in Japanese Patent Laid-Open No. 58-223953 and the like, in addition to the conductive particles, insulating organic or inorganic particles, insulating fibrous fillers, and the like are added separately to increase the compounding amount of the conductive particles, thereby preventing agglomeration between the particles and further connecting the anisotropic conductive adhesive. In order to improve the reliability, a limitation of the addition amount of the conductive particles and the insulating particles is encountered, and further, various problems are exposed in the anisotropic conductive film forming process, and a problem arises in that long-term connection reliability deteriorates even after connection.

As another conventional method for solving the insulation reliability problem, Japanese Patent Laid-Open Nos. 3-112011 and 4-259766 propose a method of attaching insulating particles to the surface of conductive particles to impart insulation. However, in the case of the above insulating conductive particles, in order to attach the insulating particles to the surface of the conductive particles, a separate adhesive or an insulating resin is used, and the bonding force is weak due to simple physical confinement. For this reason, since the insulating particles are non-ideally released due to the shear force due to the solvent and stirring during dispersion in the anisotropic conductive adhesive resin, there is a problem that can not ensure sufficient insulation. In addition, even if the insulating particles are separated during connection by heating and pressing, it is difficult to completely remove the insulating adhesion resin, which makes it difficult to control the conduction and connection reliability.

The present invention has been made to solve the above-mentioned problems, it is an insulation conductive by fixing the insulating microparticles that are easy to move and remove when hot pressing on the surface of the conductive particles through the control of materials and process conditions without the use of solvents and additives It is intended to provide a method of making the particles.

The prepared insulating conductive particles can prevent aggregation of the conductive particles and ensure dispersion stability in the anisotropic conductive adhesive resin, and at the same time, can improve the electrical conductivity, connection reliability and insulation reliability of the contained anisotropic conductive film.

These objects (1) for the anisotropic conductive film, characterized in that the insulating microparticles are mechanically bonded to the conductive particles by mechanofusion and the insulating microparticles are discontinuously coated on the surface of the conductive particles. Insulating conductive particles, an anisotropic conductive film using the same, and (2) as a method of manufacturing the conductive particles, the conductive particles and the insulating microparticles are put into a dry high-energy type mixer, and mechanofused to the surfaces of the conductive particles. It can be achieved by the method for producing insulating conductive particles for anisotropic conductive film, characterized in that for preparing the insulating conductive particles in which the insulating fine particles are mechanically bonded.

According to the present invention, through the control of materials and process conditions without the use of solvents and additives, insulating conductive particles through the surface activity and physical properties of the conductive particles and insulating microparticles by the mechanochemical coupling system of a dry high-energy mixer It is possible to improve the electrical conductivity and insulation reliability of the anisotropic conductive film by manufacturing the present invention, in the manufacturing method, provides an energy-saving and environmentally friendly manufacturing method for improving the reaction efficiency in the process without supplying a heat source from the outside.

Hereinafter, the content of the present invention will be described in detail.

1 is a schematic diagram showing a schematic structure of a dry high energy mixer applied to the present invention. The dry high energy mixer may have a rotatable inner container (A), a stationary outer container (B), a stationary scraper (C) and an armor (D). Here, the inner container A is preferably cylindrical. In addition, the armor D is fixed separately from the inner container A while being spaced apart from the inner wall of the inner container A by a predetermined distance. In this case, the portion of the armor D facing the inner wall of the inner container A is preferably larger than the radius of curvature of the inner container A, as shown.

In order to manufacture the insulating conductive particles for the anisotropic conductive film according to the present invention, first, the conductive particles and the insulating microparticles are put into the inner container A of the dry high energy mixer. Then, the inner container (A) is rotated to collect the conductive particles and the insulating fine particles toward the inner wall of the inner container (A) by centrifugal force, while the inner wall of the inner container (A) and the armor (D) The conductive particles and the insulating microparticles are passed through a space between the layers) to apply strong shear and compressive forces to the conductive particles and the insulating microparticles. As a result, sufficient thermal energy is generated between each of the conductive particles and the insulating microparticles to cause mechanofusion, and thus a strong mechanochemical bond between each of the conductive particles and the insulating microparticles. This will happen. For reference, the scraper (C) is attached to the inner wall of the inner container (A) of the conductive particles and the insulating microparticles passed between the inner container (A) and the armor (D) by mechanical compression. It scrapes away the substances present and helps to participate in the mechanofusion reaction again.

In the use of the dry high-energy mixer, the process time can be adjusted from 1 minute to several hours, and thus the structure control of the insulating conductive particles for the anisotropic conductive film produced according to this is possible.

Moreover, it is preferable that the rotation speed of the said inner container A is 500-5000 rpm. Since the strength of the mechanical force received by the conductive particles and the insulating microparticles is controlled according to the rotational speed, the morphology and the structure of the insulating conductive particles for the anisotropic conductive film can be controlled by controlling the rotational speed.

In addition, the gap between the inner wall of the inner container A and the armor D is preferably 1 to 3 mm. The gap size affects the number of collisions, thereby allowing morphology control of the insulating conductive particles for the anisotropic conductive film.

In addition, in the use of the dry high energy type mixer, the processing atmosphere can also be adjusted by air, nitrogen, argon or the like.

Figure 2 is a schematic diagram of the insulating conductive particles produced by the present invention, it shows that the insulating fine particles (F) is discontinuously coated on the surface of the conductive particles (E) to form a raspberry (raspberry) structure. Raspberry structure is when the particles are bonded to the nuclear particles, unlike the core-shell structure in which the particles are continuously connected to each other and completely bonded to form a film to coat the nuclear particles, as shown in FIG. Refers to a structure formed by bonding to nuclear particles.

The said conductive particle (E) is for electrically connecting to a to-be-connected body, such as a fine circuit electrode, and can use a wide range of particle | grains with high melting | fusing point and hardness, and excellent in electroconductivity. Examples of the conductive particles that can be used include gold (Au), silver (Ag), iron (Fe), copper (Cu), nickel (Ni), cadmium (Cd), bismuth (Bi), indium (In), and aluminum (Al). ), Palladium (Pd), platinum (Pt) and chromium (Cr) coated with at least one selected from polystyrene, polymethacrylate, polymethylmethacrylate, polyvinylacetate, divinylbenzene and benzogua The polymer particle which is any one of namin can be illustrated, A metal particle, such as silver (Ag) or nickel (Ni), can also be used as it is.

The size of the conductive particles (E) is preferably a diameter of 3㎛ 20㎛.

The insulating microparticles (F) bonded to the surface of the conductive particles (E) may be organic particles, inorganic particles or composite particles thereof. The organic particles may include polyvinyl acetate, ethylene vinyl acetate copolymer, acrylate, Any one selected from the group consisting of acrylic ester copolymers, styrene, styrene acrylate copolymers, polyurethanes, rubber latexes, natural rubbers, butyl rubbers and styrene butadiene rubbers, two or more copolymers selected from the group above, or mixtures thereof may be used. The inorganic particles may be silicon dioxide, silicon nitride, titanium dioxide or aluminum oxide. In addition, composite particles of these organic particles and inorganic particles may be used as described above.

The size of the insulating fine particles (F) is preferably 50nm to 1㎛ diameter.

3 is a schematic view of a film (ACF) formed using the conductive particles of the present invention. ACF is a double-coated tape material consisting of three components: conductive particles (G), adhesive resin, solvent (H), and additive (I). (J) conducts electrical conduction (Z-axis direction) between electrodes in the part which abuts, and the remainder other than an electrode makes an adhesive fill / cure, and adhere | attaches each other. At this time, it is very important to secure the insulation reliability in the X-Y direction in order to secure the insulation characteristics between the adjacent electrode terminals according to the fine pitch. The adhesive resin adheres the conductive particles to the adherend and at the same time exhibits conductivity, and polymer materials such as epoxy resins, polyurethanes, silicones, polyimides, phenols, polyesters, etc. are used depending on the purpose of use and required properties. In addition, suitable solvents and additives are used to improve the workability of the adhesive and the dispersibility of the conductive particles. The formation process of the film is based on a known technique, a detailed description thereof will be omitted.

(Example)

In order to prepare the insulating conductive particles for the anisotropic conductive film of the present invention, polystyrene particles coated with 4 μm of gold were used as the conductive particles, and polymethyl methacrylate having a diameter of 400 nm was used as the insulating fine particles.

In the use of the dry high-energy mixer, the gap of the mixer was fixed at 1 mm, the process time was adjusted to 30 minutes-2 hours, and the rotation speed of the inner container was adjusted to 500-3500 rpm to prepare insulating conductive particles for the anisotropic conductive film. .

The insulating conductive particles prepared in the above examples were observed through an electron microscope (SEM). Figure 4 is an SEM image of the insulating conductive particles prepared by the present invention is a polymethyl methacrylate is evenly coated on the surface of the conductive particles.

In the above, the present invention has been described with reference to the illustrated examples, which are merely examples, and the present invention may be embodied in various modifications and other embodiments that are obvious to those skilled in the art. Understand that you can.

1 is a schematic structural diagram of a dry high energy mixer applied to the present invention.

Figure 2 is a schematic diagram of the insulating conductive particles produced by the present invention.

3 is a schematic view of a film (ACF) formed using the conductive particles of the present invention.

Figure 4 is an SEM image of the insulating conductive particles produced by the present invention.

Claims (11)

Insulating conductive particles for anisotropic conductive film, characterized in that the insulating fine particles are mechanically bonded to the conductive particles by mechanofusion and the insulating fine particles are discontinuously coated on the surface of the conductive particles. The method of claim 1, wherein the conductive particles are X coated with Y, or metal particles, The X is gold (Au), silver (Ag), iron (Fe), copper (Cu), nickel (Ni), cadmium (Cd), bismuth (Bi), indium (In), aluminum (Al), palladium ( Pd), platinum (Pt) and chromium (Cr) any one or more selected from the group consisting of, The Y is an insulating conductive particle for anisotropic conductive film, characterized in that the polymer particles are any one of polystyrene, polymethacrylate, polymethyl methacrylate, polyvinylacetate, divinylbenzene, and benzoguanamine. The insulating conductive particles for anisotropic conductive films according to claim 1, wherein the conductive particles have a diameter of 3 µm to 20 µm. The method of claim 1, wherein the insulating microparticles are organic particles, inorganic particles or composite particles of the organic particles and the inorganic particles, The organic particles are selected from the group consisting of polyvinyl acetate, ethylene vinyl acetate copolymer, acrylate, acrylic ester copolymer, styrene, styrene acrylate copolymer, polyurethane, rubber latex, natural rubber, butyl rubber and styrene butadiene rubber Any one, two or more copolymers selected from the group or mixtures thereof, The inorganic particle is an insulating conductive particle for an anisotropic conductive film, characterized in that any one selected from the group consisting of silicon dioxide, silicon nitride, titanium dioxide and aluminum oxide. The insulating conductive particles for anisotropic conductive films according to claim 1, wherein the insulating fine particles have a diameter of 50 nm to 1 µm. Anisotropically conductive film comprising insulated conductive particles for anisotropically conductive film of claim 1. Mechanofusion by inserting the conductive particles and the insulating microparticles in a dry high-energy mixer, to prepare the insulating conductive particles in which the insulating microparticles are mechanically bonded to the surface of each of the conductive particles. Insulated conductive particle manufacturing method for anisotropic conductive films which are mentioned. A dry solid having a cylindrical inner container and an armor which is fixed apart from the inner container at a distance from the inner wall of the inner container and whose portion facing the inner wall of the inner container is larger than the radius of curvature of the inner container. Inserting conductive particles and insulating fine particles into the inner container of the energy mixer; By rotating the inner container to collect the conductive particles and the insulating microparticles toward the inner wall of the inner container by centrifugal force, the conductive particles and the insulating microparticles in the space between the inner wall of the inner container and the armor By applying a shear force and a compressive force to the conductive particles and the insulating fine particles by passing through, for the anisotropic conductive film, characterized in that the mechanochemical bonding by the mechanofusion occurs between the conductive particles and the insulating fine particles Method for producing insulated conductive particles. The method of claim 8, wherein the rotational speed of the inner container is 500 rpm to 5000 rpm. The method of claim 8, wherein the gap between the inner wall of the inner container and the armor is 1 mm to 3 mm. The method of claim 8, wherein the mechanochemical bonding by mechanofusion is performed in an air, nitrogen, or argon atmosphere.

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