Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1999-02-02
2001-06-12
Sells, James (Department: 1734)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S250000, C029S878000, C439S066000, C439S591000
Reexamination Certificate
active
06245175
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an anisotropic conductive film. More particularly, the present invention relates to an anisotropic conductive film that is preferably used for the connection between a semiconductor device and a substrate.
BACKGROUND ART
Along with the recent inclination toward multifunction, miniaturized and light-weight electronics, patterns of wiring circuit have been highly integrated, and multiple pins and narrow-pitched fine patterns have been employed in the field of semiconductors. In view of the fine patterns of circuits, anisotropic conductive films have been used to connect plural conductor patterns formed on a substrate with patterns of a conductor to be connected therewith or with IC or LSI. An anisotropic conductive film is a film which shows electrical conductivity in a certain direction alone, and is electrically insulated in other directions.
An anisotropic conductive film can be produced by dispersing conductive fine particles in an adhesive film, or forming through-holes in an adhesive film and filling the holes with a metal by plating.
The anisotropic conductive film can be made by the former method at low costs, but has a shortcoming in that it has poor reliability of a narrow-pitched electrical connection, due to the addition of conductive fine particles to the adhesive film.
In contrast, the latter method provides high reliability of a narrow-pitched electrical connection by forming through-holes with high precision, but is costly due to the complicated and time-consuming steps of perforation and filling of the metal.
DISCLOSURE OF THE INVENTION
It is therefore and object of the present invention to solve the above-mentioned problems and provide an anisotropic conductive film capable of establishing electrical connection at a narrow pitch, maintaining strength in the film surface direction that has not been achieved so far, and improving the adhesion to the objective substance, as well as a preferable production method thereof.
This object has been achieved by forming, on a metal thin wire, a coating layer made from an insulating material, winding said wire around a core member in a roll-like manner, heating and/or pressurizing the wires to weld and/or pressure-weld the coating layers to each other, and cutting the roll-like product in the width direction.
The anisotropic conductive film of the present invention characteristically provides the following.
(1) An anisotropic conductive film comprising an area A comprising a film substrate made from a first insulating material and plural conductive paths made from a conductive material, and an area B adjacent to the area A in the direction extending from the plane of the area A, the area B being made from an insulating material, having the same thickness as the area A, having a shape including a rectangle (0.2 mm×1 mm) and being free of a conductive path, the conductive paths being insulated from each other and piercing the film substrate in the thickness direction, each conductive path having both ends thereof exposed at the both surfaces of the film substrate, and the surface of the path except the exposed both ends being covered with a second material, and at least one of the first insulating material and the second material being an adhesive material, which is produced by the steps of
(a) winding an insulated conductor wire around a core member to give a roll-like product,
(b) heating and/or pressurizing the roll-like product to allow welding and/or pressure-welding of the coating layers, and
(c) cutting the roll-like product in a predetermined film thickness along the plane that crosses the wound insulated conductor wire, the plane forming an angle with the conductor wire,
wherein the core member cut together with the insulated conductor wire is used as a part of a product and this core member is the above-mentioned area B.
(2) The anisotropic conductive film of the above (1), wherein the conductive material is a metallic material.
(3) The anisotropic conductive film of above (2), which is produced by the steps of
(a) forming a coating layer made from the second material on a metal thin wire,
(b) forming a coating layer made from the first insulating material thereon to give an insulated conductor wire, at least one of the first insulating material and the second material being an adhesive material,
(c) winding the insulated conductor wire around a core member to give a roll-like product,
(d) heating and/or pressurizing the roll-like product to allow welding and/or pressure-welding of the coating layers made from the first insulating material, and
(e) cutting the roll-like product in a predetermined film thickness along the plane crossing the would insulated conductor wire, the plane forming an angle with the conductor wire.
(4) The anisotropic conductive film of the above (1), having a modulus of elasticity of the above-mentioned area A of 1-20000 MPa.
(5) The anisotropic conductive film of any of the above (1) to (3), having a coefficient of linear expansion of the above-mentioned area A of 2-100 ppm.
(6) The anisotropic conductive film of any of the above (1) to (3), wherein the adhesive material is a thermoplastic adhesive material or a heat curable adhesive material.
(7) The anisotropic conductive film of any of the above (1) to (3), wherein at least one of the conductive paths has at least one end projected or recessed from the plane of the film substrate.
(8) The anisotropic conductive film of any of the above (1) to (3), wherein the conductive paths form an angle with the line perpendicular to the plane of the film substrate.
(10) The anisotropic conductive film of the above (1), wherein the area B surrounds the outer periphery of the area A, or the outer periphery of the area B is surrounded by the area A, or the area B divides the area A into two.
(11) The anisotropic conductive film of the above (10), wherein the outer periphery of the area B is surrounded by the area A, the shape of the area B being a circle, and ellipse, a regular polygon, a rectangle, a rhomboid or a trapezoid.
The production method of the present invention characteristically provides the following.
(A1) A method for producing an anisotropic conductive film, comprising the steps of
(a) winding an insulated conductor wire around a core member to give a roll-like product, the insulated conductor wire comprising a wire made from a conductive material and at least two coating layers made from an insulating material,
(b) heating and/or pressurizing the roll-like winding during the step (a) or after the step (a) to allow welding and/or pressure-welding of the coating layers of the wound insulated conductor wire to integrally form a winding block, and
(c) cutting the winding block thus obtained in (b) in a predetermined film thickness along the plane crossing the wound wire, the plane forming an angle with the wound wire.
(A2) A method for producing an anisotropic conductive film, comprising the steps of
(a) winding an insulated conductor wire around a core member to give a roll-like product, the insulated conductor wire comprising a wire made from a conductive material and at least one coating layer made from an insulating material,
(b) heating and/or pressurizing the roll-like winding during the step (a) or after the step (a) to allow welding and/or pressure-welding of the coating layers of the wound insulated conductor wire to integrally form a winding block, and
(c) cutting the winding block thus obtained in (b) in a predetermined film thickness together with the core member of the winding, along the plane crossing the wound wire, the plane forming an angle with the wound wire,
wherein the core member cut together with the wire in step (c) is used as a product.
(A3) The method of the above (A1) or (A2) for producing an anisotropic conductive film, wherein the winding block obtained in the above step (b) is further molded with an insulating material and subjected to the above-mentioned step (c).
(A4) The method of above (A1) or (A2) for producing an anisotropic conductive film, said film
Hotta Yuji
Mochizuki Amane
Nitto Denko Corporation
Sells James
Sughrue Mion Zinn Macpeak & Seas, PLLC
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