JPH10134634A - Electrical connecting anisotropic conductive particle and electrical connecting anisotropic conductive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely connect the electrodes of ICs arranged at a high density by covering the whole surfaces of conductive particles with an electrical insulating micro-capsule film, arranging the conductive particles between the electrodes, applying heat and pressure, and electrically connecting the electrodes via the conductive particles. SOLUTION: Fine particles 11 of a conductive material are confined in film shells by an electric insulating material, and anisotropic micro-capsules 10 are screen-printed or sprayed on a substrate 5 provided with electrodes 4. A closely arranged anisotropic conductive micro-capsule layer is formed, opposite other electrodes are provided, another substrate is aligned, and they are heated and crimped to obtain an anisotropic conductive material connecting the electrodes 4. The film material forming the fine particles 11 of the conductive material into capsules functions as the insulating material, and the thickness of the film is reduced and it functions to stick the electrodes 4 together when heat and pressure are applied to it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrical connection in which fine particles of a conductive material are covered with an electrically insulating encapsulating film and the conductive particles are encapsulated and microencapsulated to obtain an arbitrary resolution. The present invention relates to an anisotropic conductive particle for use and an anisotropic conductive material for electrical connection.

[0002]

2. Description of the Related Art As a conventional anisotropic conductive material for electric connection,
For example, as shown in FIG. 4A, there is a film formed by dispersing conductive fine particles 1 such as metal or low-melting solder in a dispersion medium made of an insulating material 2 and forming a film. As shown in the drawing, when two substrates 5 to which electrodes 4 having a predetermined pattern are adhered are connected to each other, the above-described anisotropic conductive material is sandwiched by the substrates 5 with the electrodes 4 inside. When the whole is pressurized and heated, the insulating film is melted and extruded from between the opposing electrodes 4, the electrodes 4 are electrically connected by the conductive fine particles 1, and the substrates 5 are extruded from each other. Connected by film 2, FIG.
As shown in (b), two substrates are connected by an anisotropic conductive material.

However, in the conventional anisotropic conductive material,
Because it is difficult to uniformly disperse conductive particles having a particle size of several μm order or less in a film, it is suitable for connection of high-resolution (10 / mm or more) multi-contact electrodes for IC mounting and the like. It could not be used (in the related art, the limit is 5 lines / mm (line space = 100 μm)). For example, to obtain a resolution of 20 lines / mm, the electrode pitch is 25 μm. For this reason, it is necessary to uniformly disperse the conductive particles having a particle size of several μm order or less uniformly in the film. According to the conventional technique, the collection of the conductive particles as shown in FIG. As a result, problems such as short-circuiting between adjacent electrodes due to mixing of large-diameter particles and occurrence of an insulation state due to no intervening conductive particles as shown in FIG. 1C occurred, and sufficient reliability could not be obtained. In addition, since the conventional anisotropic conductive film is in the form of a sheet or a tape, it is complicated such as (cutting) → (temporary attachment) → (temporary adhesion) → (separator peeling) → (circuit positioning) → (full adhesion). Since such a process requires a complicated process, it leads to a prolonged connection time, a reduced yield, and the like, which leads to an increase in cost.

[0004]

Further, as an anisotropic conductive material, Japanese Unexamined Patent Publication No.
Japanese Patent Application Laid-Open No. 2-40183 discloses a technique in which conductive particles are coated with a resin insoluble in an adhesive.
This anisotropic conductive material is obtained by mixing solder metal particles into a compounded resin composed of an epoxy resin and aminoethylpiperazine, curing the mixture, and then pulverizing the particles with a pulverizer, dispersing the particles in an adhesive, and forming a connection sheet. The connection sheet is placed on the electrode so as to overlap with the electrode, and the coating is broken by the pressing force to secure the electrical connection. However, in this technique, a mass obtained by blending a large amount of conductive particles with an electrically insulating resin is finely pulverized by a pulverizer, and the insulating resin remaining on and adhered to the surface of the conductive particles after the pulverization process is performed. Is used as an insulating coating of conductive particles, so that the surface of the conductive particles is often exposed during the pulverization process. When such particles are located adjacent to each other, not only conduction in the direction of the opposing electrode, but also undesired particles In the adjacent direction. If the particles are arranged for the purpose of bonding between different adjacent electrodes, there is a problem that a short circuit occurs between the adjacent electrodes. For this reason, it is difficult to increase the arrangement density of the anisotropic conductive particles, and as a result, there is a problem in actually using for the electrical connection between the electrodes arranged at high density. In addition, the particle shape obtained by pulverization has a wide particle size distribution regardless of the shape of the conductive particles, and furthermore, because of the non-uniform shape, it is difficult to arrange at high density and uniform density, After all there is a problem in practical use. As materials relating to anisotropic conductive materials, “Electronic Technology”, 1984, Vol. 26, No. 7,
Contents described on page 7, "Nikkei Electronics" 1984
The contents are described in the July 16, 2016 issue, page 102.

Japanese Patent Application Laid-Open No. 62-35410 published after the filing of the original application of the present application discloses an anisotropic conductive material for electrical connection using a chop in which conductive fibers are coated with a coating resin. It is disclosed that the conductive fiber has a predetermined diameter, and that the anisotropic conductive fiber is formed on a film while applying a shearing force. However, in this technique, since conductive fibers are used, when the orientation of the conductive fibers is not taken into consideration, there is a possibility that conduction may occur between adjacent electrodes. Was needed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has an anisotropic conductive particle for electrical connection and an anisotropic conductive material for electrical connection that can reliably connect electrodes of an IC or the like arranged at high density. Is provided.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides conductive particles and an electrically insulating microencapsulated film covering the entire surface of the conductive particles. And anisotropic conductive particles for electrical connection for electrically connecting the electrodes via the conductive particles by applying heat and pressure. Furthermore, the present invention binds a plurality of anisotropic conductive particles having conductive particles and an electrically insulating microencapsulated film covering the entire surface of the conductive particles, and the plurality of anisotropic conductive particles. And a film material for electrical connection between the electrodes through the conductive particles by applying heat and pressure, which is disposed between the electrodes, and having a film-like anisotropic conductive material for electrical connection. It is. Note that the microencapsulated film in the present invention refers to a film formed so as to cover the entire core material by a microencapsulation method. In the process of the electrical connection of the present invention, heat and pressure are applied in a state in which anisotropic conductive particles are arranged between the electrodes, as described in JP-A-62-40183. Then, the electrically insulating material near the electrodes is removed from the surface of the conductive particles, and electrical connection is made between the electrodes via the conductive particles. Since the anisotropic conductive particles for electrical connection of the present invention have a microencapsulated film on the entire surface of the conductive particles, a microencapsulated film having a uniform thickness according to the shape of the conductive particles is formed for each conductive particle. The particles are coated, and the particle diameter and the shape of the particles become uniform. For this reason, when particles are arranged on the electrode, the anisotropic conductive particles are arranged with high density and uniform density. In addition, since the anisotropic conductive material for electrical connection of the present invention similarly uses anisotropic conductive particles having a uniform shape and a uniform diameter, the anisotropic conductive particles are dispersed at a high density and a uniform density in the film material. It will be. Further, in the present invention, since the electrically insulating microencapsulated film is provided on the entire surface of the conductive particles, the electrically insulating microencapsulated film always exists in the adjacent portion even if the particles are adjacent to each other. Therefore, occurrence of short circuit between adjacent electrodes is prevented.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the anisotropically conductive particles for electrical connection and the anisotropically conductive material for electrical connection according to the present invention will be described in detail. FIG. 1 shows an embodiment of the present invention, and the same parts as those in FIG. 4 are denoted by the same reference numerals, and therefore, the duplicate description is omitted. Screen printing or spraying anisotropically conductive microcapsules (anisotropically conductive particles) 10, which are encapsulated by being encapsulated in a covering shell with an insulating substance 12 and microencapsulated, on a substrate 5 on which the electrodes 4 are provided. Forming an anisotropic conductive microcapsule layer that is closely arranged with the other substrate provided with another opposing electrode, and then heat-pressed to form an anisotropic conductive material that connects the electrodes. is there.

Here, as shown in FIG. 2, an anisotropic conductive microcapsule (anisotropic conductive particles) 10 is composed of a core material (conductive particles) 11 and a single layer or multiple layers covering the core material 11. Film material (electrically insulating microencapsulated film)
12, the core material being enclosed by the coating material.

As the core substance 11, gold, platinum, silver, copper,
Metals and metal compounds such as iron, nickel, aluminum, and chromium (ITO, solder, and the like), conductive inorganics and inorganic compounds such as conductive carbon, and conductive organic compounds such as organometallic compounds can be used. The coating material 12 may be a heat-insulating polymer such as phenol resin, urea resin, melamine resin, allyl resin, furan resin, polyester, epoxy resin, silicone resin, polyimide resin, polyurethane, or Teflon resin. Curable polymer, polyethylene, polypropylene, polybutylene, polymethyl methacrylate, polystyrene, acrylonitrile-styrene resin, styrene-butadiene resin, acrylonitrile-styrene-butadiene resin,
Vinyl resin, polyamide resin, polyester resin, polycarbonate, polyacetal, ionomer resin, polyether sulfone, poly (phenyl oxide), poly (phenylene sulfide), polysulfone, polyurethane, fluororesin (PTFE, PCTFE, polyvinylidene fluoride) ) And organic-inorganic compounds such as fibrous resins (ethyl cellulose, cellulose acetate, cellulose propionate, cellulose nitrate, etc.).

When the core substance 11 is encapsulated and microencapsulated with the film substance 12, a chemical manufacturing method (for example, an interfacial polymerization method, an in situ polymerization method, a curing in liquid coating method, etc.) or a physical method is used.・ Mechanical manufacturing method (for example,
Spray drying method, air suspension coating method, vacuum evaporation coating method, electrostatic coalescence method, melting dispersion cooling method, inorganic encapsulation method, etc.), or physicochemical manufacturing method (eg coacervation method, interfacial precipitation) Law). References on microcapsules include “Microcapsules” by Tamotsu Kondo and Masazumi Koishi, published by Sankyo, 198.
There are many such as the third printing issuance on March 1, 1 year.

The coating material 12 for encapsulating and microencapsulating the core material 11 not only functions as an insulating material but also reduces the film thickness coated on the surface of the core material 11 by applying heat and pressure. 5 has a function of adhering the electrodes 4 formed on each other. Film substance 1
2 is used for insulation, adhesion, and slip (by appropriately adjusting the slip between the anisotropic conductive microcapsules, it becomes easy to form a single layer when applied to the lower substrate) by multiplexing. Functions can be divided to improve reliability.

[0013]

Next, the formation of an anisotropic conductive material will be described with reference to FIGS. 1 (a) and 1 (b), taking connection of a substrate as an example. The anisotropic conductive microcapsules 10 as prepared in FIG.
μm (a value determined from the requirement of a resolution of 20 lines / mm), and this is applied to a predetermined portion of the lower electrode substrate 5 by screen printing or spraying (shown in FIG. 1A). Next, after aligning the upper electrode substrate 5 (or a flexible connector, an IC electrode pad, etc.), they are heat-pressed to reduce the thickness of the electric insulating film material 12 so that the electrode between the two substrates is formed as shown in FIG. ).

As shown in FIG. 1B, when an electrical connection is made using the anisotropic conductive material according to the present invention, the anisotropic conductive material 10 having a uniform particle size exists uniformly on the substrate 5 and each Since the conductive material is covered with the insulating material, an insulating layer is always formed between the conductive fine particles, and an electrical short-circuit phenomenon does not occur between the conductive fine particles. Therefore, the conventional problem as shown in FIG. 5 does not occur. Therefore, both the reliability and the resolution can be improved. Note that the resolution is as follows:
Arbitrary values can be obtained by adjusting the particle diameter and the thickness of the film 12. BACKGROUND ART Conventionally, when forming an anisotropic conductive film, an insulating film material and conductive particles are directly kneaded and then sheet-shaped or shaped. Similarly, in the present invention, as shown in FIG. 3, the conductive particles are microencapsulated to form anisotropic conductive microcapsules 10, which are formed into a sheet-shaped or tape-shaped anisotropic conductive microcapsule 10 by a roller 15 (or a heat roller or the like). Conductive films can be manufactured.

[0015]

As described above, according to the anisotropically conductive particles for electrical connection and the anisotropically conductive material for electrical connection of the present invention, an electrically insulating microencapsulated film is formed on the entire surface of the conductive particles. Because, even if the anisotropic conductive particles aggregate between the adjacent electrodes, a short circuit between the adjacent anisotropic conductive particles does not occur, and the anisotropic conductive particles are arranged at high density and uniform density. In addition, it is possible to reliably electrically connect the electrodes arranged at high density.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the microencapsulated anisotropic conductive particles according to the present invention.

FIG. 3 is a diagram illustrating the production of an anisotropic conductive film according to the present invention.

FIG. 4 is a diagram illustrating connection of electrodes using a conventional anisotropic conductive material.

FIG. 5 is an explanatory view showing occurrence of a connection trouble due to a conventional material.

[Explanation of symbols]

4 electrodes, 5 substrates, 10 anisotropic conductive microcapsules, 11 core materials, 12 coating materials.

Claims (2)

[Claims] 1. An electro-conductive micro-encapsulated film for covering said conductive particles, wherein said micro-encapsulated film is provided between said electrodes, and heat and pressure are applied between said electrodes so that said conductive particles are interposed therebetween. Anisotropic conductive particles for electrical connection for electrically connecting the electrodes. 2. A plurality of anisotropic conductive particles having conductive particles and an electrically insulating macro-encapsulated coating covering the conductive particles, and a film material binding the plurality of anisotropic conductive particles. A film-shaped anisotropic conductive material for electrical connection, which is disposed between the electrodes to apply heat and pressure to electrically connect the electrodes via the conductive particles.