JPH02852Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention is an anisotropically conductive wiring member, especially an anisotropically conductive wiring member with excellent oxidation resistance and sulfidation resistance, which is used in electronic devices. It is related to.

(Prior art and its problems) Conventional flexible wiring members are usually made by using an insulating adhesive layer b on an insulating flexible film a as shown in Fig. 6 from the viewpoint of conductivity and workability. However, since copper has poor oxidation resistance and sulfidation resistance, it is plated with a precious metal or coated with carbon ink, etc. It is necessary to make the layer d chemically stable. Precious metal plating poses a cost issue, while ink coatings make alignment difficult and prone to leaks between adjacent conductors as circuits become smaller. In addition, the formation of the chemically stable layer d on the metal conductive material c makes the unevenness on the adhesive layer b even larger, so when connecting this wiring member,
The drawback was that moisture due to condensation or the like accumulates in the gaps formed between the uneven surfaces, causing insulation failure.

(Means for solving the problem) The present invention provides an anisotropic conductive wiring member with excellent oxidation resistance and sulfidation resistance, and this wiring member is coated on one side of an insulating flexible film. Conductive wires are placed on a flexible anisotropically conductive wiring board, which is formed by arranging conductive wires in a parallel pattern at intervals through an insulating adhesive or an adhesive layer (hereinafter simply referred to as the adhesive layer). An insulating layer made of conductive particles dispersed therein is provided, and at least a portion of the conductive particles are disposed with one end in contact with the conductive wire and the other end exposed to the outside. be.

This will be explained first with reference to the embodiments shown in FIGS. 1 to 4. In the figures, 1 is an insulating flexible film, 2 is an insulating adhesive layer provided on one side of the film,
Reference numeral 3 designates conductive wires arranged in a parallel pattern on this surface while maintaining a distance from each other, that is, maintaining insulation properties. The conductive wire 3 may be provided so that the entirety thereof is located on the upper surface of the adhesive layer 2 as shown in FIGS. One side or the entirety may be buried inside the adhesive layer 2, and the other side may be exposed upward, or may be provided so as to be in contact with the conductive particles 5, which will be described later. Reference numeral 4 denotes an insulating layer formed by dispersing and blending conductive particles 5, which is provided over the conductive wires 3, filling the gaps therebetween and covering the entire surface of the adhesive layer 2. At least a portion of the conductive particles 5 are disposed such that one end thereof is in electrical contact with the conductive wire 3 and the other end is exposed to the outside. Incidentally, FIG. 5 shows the connection state of the anisotropically conductive wiring member 6 according to the present invention with the connecting member 9, where 7 is the substrate thereof and 8 is the connecting terminal.

The insulating flexible film used in the wiring member of the present invention having the above structure is made of synthetic resins such as polyimide, polyester, polyester containing aramid fibers, epoxy containing glass fibers, ethylene-vinyl acetate copolymer, and polymethyl methacrylate. Films and synthetic rubber films such as chloroprene, nitrile rubber, and silicone are used. In the case of synthetic resin, the thickness of these films is 5 μm to 5 mm, preferably 10 to 100 μm, in the case of rubber, taking into account ease of adaptation to irregularities on the substrate, degree of wrinkle generation, flexibility, etc. 5 μm to 5 mm, preferably 100 to 5 mm in terms of tear strength and ease of familiarization
It is 500μm.

The materials used to form the insulating adhesive layer include:
Tackifier and viscosity are added to resin components such as ethylene-vinyl acetate copolymer, ethylene-acrylic copolymer, iomonomer (derivative of ethylene-acrylic acid copolymer), phenoxy resin, medium to high molecular weight polyamide, and polyester resin. Hot melt adhesives with added modifiers, and chloroprene-based adhesives,
Nitrile rubber type, polyvinyl acetate type, vinyl chloride type, amino resin type, urea type, melamine resin type, phenolic resin type, novolac resin type, resorcinol formaldehyde resin type, xylene resin type,
Examples include various thermoplastic or thermosetting pressure-sensitive adhesives or adhesives such as epoxy, polyisocyanate, unsaturated silicone, and polyester adhesives. The thickness of these materials is preferably 5 to 50 μm in the case of resin, and 5 to 100 μm in the case of rubber.

The conductive wires are etched metal plates made of copper, stainless steel, phosphor bronze, beryllium copper, nickel, aluminum, or the like, or metal wires made of these materials. These cross-sectional shapes can be any shape such as round, triangular, square, or trapezoidal, and their diameter is 0.1 μm to 1 mm, preferably 0.1 to 1 mm.
It is 200μm.

As described above, a plurality of conductive wires are arranged in a parallel pattern at intervals, and the wiring pitch is preferably 1 to 1000 .mu.m, usually 30 to 400 .mu.m.

On the other hand, conductive particle materials include metal oxides such as tungsten carbide, tin oxide, and titanium nitride, metal nitrides, or metal carbides, gold-plated or carbon-coated glass beads, and conductive particles mixed with carbon. Examples include rubber pieces, carbon balloons, etc., which are highly resistant to oxidation and sulfidation, but among these, metal oxides,
Metal nitrides or metal carbides are preferred, and tungsten carbide is particularly preferred. The shape of these particles can be arbitrary, such as acicular, spherical, or irregular, but their size is determined by the distance between the conductive wires, i.e., 1 to 1000 μm as described above, in order to maintain insulation from adjacent conductive wires. 1/3 or less, usually 0.3~
It is preferable to use a particle size within the range of 200 μm with a variation within ±5 μm of the average particle size depending on the spacing between the conductive wires.

As a material for dispersing and blending these conductive particles to form an insulating layer, a synthetic resin or synthetic rubber having insulating properties is used. 2) ethylene-vinyl acetate copolymer system, ethylene-acrylic copolymer system, iomonomer (derivative of ethylene-acrylic acid copolymer)
system, phenoxy resin system, polyamide resin system, chloroprene system, nitrile rubber system, polyvinyl acetate system, vinyl chloride system, amino resin system, urea system, melamine resin system, phenolic resin system, novolac resin system, resorcinol formaldehyde resin system, Non-adhesive or non-adhesive thermoplastic or thermosetting materials such as xylene resin, epoxy, polyisocyanate, unsaturated silicone, and polyester are listed. It is preferable to have one. Further, the thickness of this insulating layer on the conductive wire is preferably in the range of 20 to 95% of the size of the particles used so that the conductive particles in the insulating layer in contact with it are exposed to the outside. In general, as in the case of the adhesive layer described above, a suitable thickness is 5 to 50 μm for resin and 5 to 100 μm for rubber.

In manufacturing the wiring member of the present invention, an insulating adhesive layer is first formed on the above-mentioned insulating flexible film. This can be achieved by conventionally known methods such as printing or coating. In this case, a commercially available film in which an adhesive layer is already laminated may be used. In order to make this into a flexible anisotropic conductive wiring board, conductive wires can be placed on this adhesive layer and press hardened. However, when using metal wires as the conductive wires, The laminated film is wound around a drum, and while the film is rotated, the position of the metal wire being fed out is shifted little by little in the axial direction.The film is wound into a coil and fixed, and after being cut to a predetermined length, it is removed from the drum. method is adopted. Note that this wiring board may be formed by laminating an insulating flexible film onto a commercially available laminated sheet in which conductive wires are provided on an adhesive layer.

Next, by forming an insulating layer on this flexible anisotropically conductive wiring board, the anisotropically conductive wiring member of the present invention is obtained. The resulting ink is mixed with a solvent such as kerosene, celloacetate, or isophorone using a mixer, Raikai machine, kneader, etc., and the resulting ink is printed or applied with a coater on a flexible printed wiring board, and then it is applied under pressure. 2) Use an adhesive or adhesive as the insulating layer material and apply it on the flexible anisotropic conductive wiring board by printing or using a coater in advance. After that, 1 to 8 conductive particles
There is a method of spraying conductive particles at a rate of 2 to 3 particles/mm ² , preferably 2 to 3 particles/mm ² , and then pressing them under heat to force and fix the conductive particles into the insulating layer material. Due to the accompanying contraction of the insulating layer material, at least a portion of the conductive particles will be in a state where one end thereof is exposed to the outside on the conductive wire.

The anisotropically conductive wiring member according to the present invention thus obtained is connected to a connecting member 9 as shown in FIG. 5 for general use.
The connecting terminals 8 and 8 can be bonded by adhesive, or if the insulating layer material is a thermoplastic resin, by heat-pressure integration, or if the insulating layer material is a thermosetting resin, the wiring member is uncured or semi-cured. A method is adopted in which this connection is left in the same state and integrated with heat and pressure.

Next, specific aspects of the present invention will be explained using examples.

Example 1 A flexible laminate consisting of a polyimide film with a thickness of 25 μm, an epoxy adhesive layer with a thickness of 35 μm, and a copper foil was used, and the width and spacing of the conductive wires were 0.1 mm each. Etching was performed to obtain a flexible anisotropically conductive wiring board.

Next, 40 parts by weight of tungsten carbide powder with a particle size of 25 μm, 100 parts by weight of silicone rubber KE151KU (manufactured by Shin-Etsu Chemical Co., Ltd.), 200 parts by weight of kerosene, and 2 parts by weight of vulcanizing agent C-2 (manufactured by Shin-Etsu Chemical Co., Ltd.) Mix this to make an ink, and screen print this onto the conductive wire on the above wiring board to a thickness of 20 μm.
It was vulcanized and hardened while applying pressure. Due to vulcanization shrinkage of the resin, a portion of each tungsten carbide particle relatively protruded from the sheet surface, and an anisotropically conductive wiring member according to the present invention was obtained.

Next, this wiring member is cut in a direction perpendicular to the orientation direction of the conductive wires to make a 20 mm wide piece, and a group of parallel terminals are arranged on the board as shown in Figure 5.
It was placed between a pair of connecting members arranged with a width of 0.6 mm and a pitch of 1.2 mm, and connected by pressing at 50 kg/cm ² for 1 minute at room temperature. When I measured the resistance of this, I found that
It was 0.3 to 2Ω, and it was found that the insulation between the parallel terminal groups was sufficiently maintained.

Example 2 A mixture of 100 parts by weight of silicone rubber KE151KU (manufactured by Shin-Etsu Chemical Co., Ltd.) and 2 parts by weight of vulcanizing agent C-2 (manufactured by Shin-Etsu Chemical Co., Ltd.) was mixed on a polyester sheet with a thickness of 75 μm. The laminated sheet was topped with a length of 0.1 mm, and the resulting laminated sheet was wound around a rotating drum and fixed. While this drum was rotating, a copper wire with a diameter of 40 μm was moved in the axial direction at a rate of 0.1 mm/rotation and was fed out from the bobbin and wound onto the laminated sheet to form a coil with a pitch of 0.1 mm.
This was cut along two lines parallel to the axial direction and removed from the drum to obtain a flexible anisotropically conductive wiring board.

In addition, 40 parts by weight of tungsten carbide powder with a particle size of 15 μm, 100 parts by weight of silicone rubber KE151KU (manufactured by Shin-Etsu Chemical Co., Ltd.), 200 parts by weight of kerosene, and 2 parts by weight of vulcanizing agent C-2 (manufactured by Shin-Etsu Chemical Co., Ltd.) When the ink was screen printed on the above wiring board to a thickness of 10 μm on a conductive wire and cured by heat and pressure, the silicone rubber was heated and contracted to form an ink of tungsten carbide. A part of the particles relatively protruded from the sheet surface, and an anisotropically conductive wiring member according to the present invention was obtained.

When the resistance of the connection was measured in the same manner as in the previous example, it was 0.5 to 1Ω.

(Effects of the invention) The anisotropic conductive wiring member according to the invention has good oxidation resistance and sulfidation resistance because the conductor is covered with an insulating layer.

Cost is low because there is no need to plate conductive wires.

Since the conductive particles protrude beyond the surface of the insulating layer, contact stability is good.

Since the insulating layer fills the gap between the conductive wires and is elastically crimped to the connecting member, there is no risk of moisture entering the gap between the conductive wire and the connecting member.

Since the conductive wire is sandwiched between the flexible film and the insulating layer, there is no peeling or leakage of the conductive wire.

[Brief explanation of the drawing]

Figures 1 to 4 are cross-sectional explanatory views of different embodiments of the present invention, and Figures 5a and 5b each illustrate the state of connection of the anisotropically conductive wiring member to the connection member according to the present invention. A perspective view, a bottom view, and a cross-sectional view of the conventional example are shown in FIG. Explanation of main symbols, 1... Insulating flexible film, 2... Insulating adhesive layer, 3... Conductive wire, 4...
...Insulating layer, 5...Electroconductive particles.

Claims (1)

[Claims for Utility Model Registration] 1. A flexible film in which conductive wires are arranged in a parallel pattern at intervals on one side of an insulating flexible film via an insulating adhesive or an adhesive layer. An insulating layer formed by dispersing conductive particles is provided on a conductive wiring board, and at least a part of the conductive particles is arranged with one end in contact with the conductive wire and the other end exposed to the outside. An anisotropically conductive wiring member characterized by: 2. The anisotropically conductive wiring member according to claim 1, wherein the conductive particles are made of metal carbide, metal oxide, or metal nitride. 3. The anisotropically conductive wiring member according to claim 1, wherein the conductive particles have a diameter that is 1/3 or less of the distance between the conductive wires. 4. The anisotropically conductive wiring member according to claim 1, wherein the insulating layer is made of a rubber-like elastic material.