JPH04196016A - Manufacture of anisotropic conductive sheet - Google Patents

Abstract

PURPOSE:To unify intervals between linear conductors and perform highly reliable contact connecting by adjacently arranging a plurality of insulatedly coated wires so as to solidify the insulatedly coated parts to form a wire aggregate and to cut it in the direction orthogonal to the longitudinal direction of the wire. CONSTITUTION:A plurality of insulatedly coated wires 1a are adjacently arranged, insulatedly coated parts 1b of the wires 1a are thermally press-fitted or solidified by a solvent to form a wire aggregate which is to be cut in the direction orthogonal to the longitudinal direction of the wire and the cut surfaces are made flat as occasion demands so as to be processed in a sheet shape 3. Accordingly, the wire intervals of an anisotropic conductive sheet are determined by the diameter of the insulatedly coated wires so that the wires can be arrayed at constant intervals when the diversity of diameters is controlled. Thereby, no rough or dense part in a wire distribution is generated so as to unify the number of wires per unit area at any part of the sheet surface and to provide highly reliable contact-connection between the opposing electrode pads.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing an anisotropic conductive sheet for contacting and connecting electrode butts of electronic components such as semiconductor LSI or circuit boards facing each other. In particular, the present invention relates to a manufacturing method suitable for making electrical contact between electrode pads at a narrow pitch.

[Conventional technology]

As electronic components become smaller and thinner, the pitch of the electrode pads of electronic components such as semiconductor LSIs or circuit boards is becoming narrower, and contact connections with high electrical reliability are required. In recent years, when making contact connections with the electrode pads of electronic components and circuit boards facing each other, there is a gap between the two electrode pads. A method is used in which an anisotropic conductive sheet having conductivity only in the thickness direction is interposed and the two circuit boards are fixed under pressure. Such an anisotropic conductive sea! For example, as a manufacturing method for
In 709, short linear conductors in the shape of ficimene with magnetic properties of approximately equal length are dispersed in a matrix liquid having electrically insulating properties, and this mixed liquid is dispersed into a matrix liquid having a length equivalent to that of the linear conductors. A method is used in which the matrix liquid is solidified in a state in which it is filled between two planes having an interval, a uniform magnetic field is applied in the thickness direction, and the linear conductors are oriented in the thickness state of the mixed liquid. The anisotropic conductive sheet made by the manufacturing process described above is either relatively easy to manufacture or does not take into account the spacing between adjacent linear conductors, and the density of the linear conductors is limited. Variations occur, making it difficult to determine the specifications of the contactable electrode butt size.

[Problem to be solved by the invention]

In the above conventional technology, short linear conductors of approximately equal length are dispersed in an insulating matrix liquid and are oriented and solidified by the action of a magnetic field, and the intervals between the linear conductors are constant. Even if the electrode butt size or electrode pitch is such that sufficient contact can be made in the dense areas, insufficient contact may occur in the rough areas.

In addition, it is not easy to determine the contactable electrode butt size or pitch, and furthermore, it is difficult to determine the contactable electrode butt size or pitch, and it is also difficult to determine the individual The distribution of conductors is all different;
For example, there is a problem in that it is important to determine the minimum contactable electrode pad size and electrode pitch.

An object of the present invention is to solve the above-mentioned problems, and to provide a method for manufacturing an anisotropic conductive sheet that makes the distance between linear conductors constant and realizes highly reliable contact connection. .

[Means to solve the problem]

In order to achieve the above objective, a plurality of insulated wires are arranged close to each other, the insulated parts of the wires are bonded by thermocompression or fixed with a solvent to form a wire assembly, and the wires are arranged perpendicular to the longitudinal direction of the wires. We adopted a manufacturing method in which the material is cut in the same direction, and if necessary, the cut surface is flattened and processed into a sheet shape.

More preferably, following the above step, a step of applying corrosion-resistant, good conductor, or hard metal plating to the wire surface of the cross section is added, or after pressurizing the wire into a sheet shape, a part of the insulating coating is removed by etching. The contact characteristics can be improved by removing the wire and adding a step of plating the wire surface with corrosion-resistant, good conductor, or hard metal, if necessary.

[Effect]

According to the above manufacturing method, the wire spacing of the anisotropic conductive sheet is determined by the diameter of the insulated wire, and if the variation in diameter is controlled, the wires can be arranged at a constant spacing, resulting in a rough wire distribution. There are no rough or dense areas, and the number of wires per unit area can be kept constant in any part of the sheet surface.

〔Example〕

An embodiment according to the present invention will be described below with reference to FIGS. 1, 2, and 3.
This will be explained using figures. FIG. 1 shows a manufacturing process of an embodiment of the present invention. In this example, as shown,
First, wires such as tungsten (W), stainless steel, or beryllium (Be)-copper (Cu) are coated, or if necessary, the surface of these wires is coated with nickel (Ni) or gold (Au).
), a large number of wire rods are prepared in which the surface of the wire is plated with metal such as rhodium (Rh) and coated with an insulating material such as silicone rubber or fluororesin.

Next, the wire 1 is inserted into a spring-like cylindrical coil-shaped holding jig 2 as shown in FIG. 2, for example, to form a wire assembly. Next, for example, the adjacent insulation coating portion 1b
Apply external force until there is no gap between 1b and 1b', and then heat to separate the adjacent insulation coatings 1b and 1b'
Glue. Alternatively, for example, when the covered wires are gathered together, a low load is applied from the outside and the insulation coating is left in a liquid or atmosphere that melts the insulation coating, and then the gaps between the insulation coatings 1b and lb' of adjacent wires are removed. Add force from the outside until it runs out, and hold until the solvent is sufficiently dry. The wire assembly thus produced is cut perpendicularly to the longitudinal direction of the wires, and the cut surfaces are flattened if necessary to produce an anisotropic conductive sheet 3 as shown in FIG. 3. Furthermore, even if the wire surface (1a) on the cut surface is plated with metal such as nickel (Ni), gold (Au), rhodium (Rh), etc., the insulation coating 1b on the cut surface is partially removed by etching, etc. Even more exposed wires
The surface a may be plated with the above metal. The completed anisotropic conductive sheet 3 may be cut and used as necessary.

According to the second method, the wires can be arranged regularly at regular intervals, and as a result, the number of wires per unit area can be made constant in any part of the sheet surface, which is different from the conventional technology. In comparison, conduction defects are significantly reduced, and the reliability of contact connection is greatly improved.

〔Effect of the invention〕

As explained above, according to the present invention, when the electrode pads of a semiconductor LSI chip or a circuit board and the opposing circuit board are connected in contact with each other using an anisotropic conductive sheet, the opposing electrode pads can be contacted with high reliability. It has the effect of being connected.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the manufacturing process according to the present invention, and FIG.
The figure is a perspective view of wires arranged in close proximity in the manufacturing process according to the present invention, and FIG. 3 is a perspective view of an anisotropic conductive sheet according to the present invention. 1a...Wire 1b...Insulation coating 2.
...Cylindrical coil holding jig 3...Anisotropic conductive sheet

Claims (1)

[Claims] 1. A method for manufacturing an anisotropic conductive sheet for electrically connecting an electrode pad of a semiconductor LSI or circuit board to an electrode pad of another semiconductor LSI or circuit board facing each other, a first step of arranging a plurality of insulated wires in parallel in close proximity; a second step of forming a wire assembly by thermocompression bonding or fixing the insulating coatings of the closely arranged wires with a solvent; A third step of cutting the wire assembly in a direction perpendicular to the longitudinal direction of the wires and, if necessary, flattening the cut surfaces. Method. 2. An anisotropic conductive sheet characterized in that, following the third step according to claim 1, a fourth step is added in which the cross-sectional metal surface is plated with a metal having high conductivity, corrosion resistance, or hardness. Production method. 3. A method for manufacturing an anisotropic conductive sheet, comprising adding a fourth step of partially removing the surface of the cross-sectional insulator by etching, subsequent to the third step according to claim 1. 4. A method for producing an anisotropic conductive sheet, characterized in that, following the fourth step according to claim 3, a fifth step is added in which the metal surface is plated with a metal having high conductivity, corrosion resistance, or hardness. . 5. The wire is made of tungsten (W), stainless steel, or beryllium (Be)-copper (Cu), and if necessary, the surface is coated with nickel (Ni), gold (Au), rhodium (Rh), etc. 5. The method for producing an anisotropic conductive sheet according to claim 1, wherein the anisotropic conductive sheet is subjected to metal plating. 6. The method for producing an anisotropic sheet according to claim 1, 2, 3, 4, or 5, wherein the insulator covering the wire surface is made of silicone rubber, fluororesin, or the like.