JPS62234804A - Anisotropic conductive film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an anisotropic conductive film, and particularly to an anisotropic conductive film that does not require a pressure jig and can be easily mounted.

[Prior art and its problems]

As electronic devices become smaller, thinner, and more precise, the density of various parts including flat displays such as LCDs increases, and there is a strong desire to develop connection materials that can handle the thinning of the connection parts with various wiring lines. ing.

In response to this, in recent years, anisotropic conductive films that have electrical conductivity only in a certain desired direction and electrical insulation in other directions have been used as connecting materials between fine electrode patterns. Attention has been paid.

For example, as shown in FIG. 4, there is an anisotropically conductive rubber connector 100 in which a large number of thin metal wires 102 are embedded in the thickness direction of a rubber sheet 101. As shown in the cross-sectional view in FIG.
As shown in the figure, a positioning frame 104 is arranged at a predetermined position on a wiring board 103, and the anisotropically conductive rubber connector 100 is arranged inside the frame 104, and a connecting frame 104 mounted on a chip carrier 105 is also arranged. IC chip (not shown)
A method is used in which a pressure plate 106 is placed on the I
Connection between the C chip and the wiring board 103 is achieved.

Such rubber connectors require a clamping and pressing jig for mounting, making the mounting process complicated and having poor workability.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide an anisotropic conductive film that is easy to mount.

[Means for solving problems]

Therefore, in the present invention, adhesive means are arranged on both the front and back surfaces of an anisotropic conductive film in which thin conductive wires are embedded at predetermined intervals in the thickness direction of the insulating film.

[Effect]

For example, thermosetting adhesive layers are placed on both the front and back surfaces of the anisotropic conductive film. Thereby, upon mounting, adhesion can be easily achieved only by thermocompression bonding, and conductivity can be provided only in the thickness direction of the film.

In addition, by providing metal protrusions that slightly protrude from the sheet surface at both ends of the conductive thin wire, and configuring the metal protrusions with a metal that will alloy the metal protrusions with the wiring pattern to be connected, Adhesion and anisotropic conduction can be easily achieved by crimping alone.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Example 1 FIG. 1 is a sectional view of an anisotropic conductive film according to an example of the present invention.

This anisotropic conductive film is coated on both sides of a base rubber sheet 1 made of butadiene rubber with a film thickness of 0.1 to several dozen.
Thermosetting adhesive layer 2 consisting of dozens of polyimide resin films
a, 2b, and thin nickel wires 3 at predetermined intervals.
is embedded, and both ends 3a of the thin nickel wire 3 are made to protrude into the thermosetting adhesive layers 2a, 2b.

When mounting, as shown in FIG. 2, the anisotropic conductive film E is placed around the bonding pad 4p on the wiring board 4.
The IC chip 5 to be connected is placed face down with the bonding pad 5p facing down) and bonded by thermocompression.

In this way, the IC chip can be mounted on the wiring board extremely easily using the thermosetting adhesive layers 2a and 2b without using any special pressure holding jig. Therefore, no jig is required after crimping. Furthermore, the connection resistance value is low, and it can be used for large current (2A/c112 or more).

Example 2 FIGS. 3(a) and 3(b) are cross-sectional views of an anisotropic conductive film according to another example of the present invention. (FIG. 3(b) is a partially enlarged view of FIG. 3(a).) This anisotropic conductive film is attached at both ends in the thickness direction of the base material rubber sheet 11 made of silicone rubber with a film thickness of 500 m. Copper thin wires 13 are embedded at an interval of 25,000 lines/clI2 so that 151U of nickel wires protrude, and a coating layer 14 made of a solder plating layer is provided at both ends of the nickel thin wires 13.

In practice, in the same manner as in Example 1, an IC chip to be connected is placed around the bonding pad on the wiring board via the anisotropic conductive film and bonded by thermocompression.

For example, when the bonding pad has an Aff pattern, the tin of the covering layer 14 and the copper of the bonding pad are eutecticized by heating, and physical adhesion and electrical bonding can be achieved without using a special jig. Connection is easily achieved.

In the examples, silicone rubber and butadiene rubber were used as the base rubber sheet, but other rubber-like transparent elastic materials such as ethylene-propylene rubber, butyl rubber, in-prene rubber, nitrile-butadiene rubber, urethane rubber, and polyester were used. It is also possible to use Also,
Crosslinking agents, curing agents, reinforcing fillers, extenders,
Stabilizers, colorants, pigments, lubricants, softeners, coupling agents, foaming agents, antioxidants, thermal conductivity imparters, heat resistance improvers, and the like may be added.

Further, the base material is not limited to an elastic body such as a rubber sheet, but may be an inelastic body such as a molded resin body. However, when bonding over a wide area, use of an elastic body can alleviate the presence of unevenness on the substrate, making it possible to perform a highly reliable connection.

Furthermore, as conductive thin wires, in addition to nickel and copper,
Metals such as iron, tin, aluminum, zinc, gold, silver, palladium, tungsten, titanium, etc., alloys such as nichrome phosphorus bronze, stainless steel, and nickel silver, tin oxide (Sn
The material can be appropriately selected from conductive metal compounds such as O2), indium oxide (In203), and indium tin oxide (ITO), conductive carbon fibers, and silicon carbide.

Furthermore, as the adhesive layer, thermosetting adhesives such as polyimide-based silicone-based adhesives, thermoplastic adhesives such as polystyrene-polyethylene, etc. can be used.

In addition, the metal protrusions are not limited to the solder plating layer, but depending on the material of the wiring pattern to be connected, materials that form an alloy with this, such as forming a eutectic or solid solution, etc. It is possible to select as appropriate from the following. The metal protrusions can be multi-layered. <If the IC chip's bonding pad is Al
In addition, the anisotropic conductive film of the present invention can be used not only for mounting IC chips, but also for LSI, various displays, F
Effective for bulk connection of multi-contact electrodes in various electronic components such as PC%PWB.

〔effect〕

As described above, according to the present invention, conductive thin wires are embedded at predetermined intervals in the thickness direction of an insulating film so that both ends are exposed, and adhesive means are provided on both the front and back surfaces of the film. Therefore, there is no need for a special pressure clamping jig, and it can be mounted extremely easily.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an anisotropic conductive film of an example of the present invention,
FIG. 2 is a diagram showing a mounting example using the same anisotropic conductive film, and FIGS. Figure (b) is an enlarged view of the main part of Figure 3 (a)), Figures 4 and 5 are diagrams showing a conventional anisotropic conductive film, and Figure 6 is a diagram showing a conventional anisotropic conductive film. It is a figure which shows the example of implementation used. 100...Rubber connector, 101...Rubber sheet,
102... Metal thin wire, 103... Wiring board, 104
...Frame, 105...Chip carrier, 106...
Holding plate, 1... Base material rubber sheet, 2a, 2b... Thermosetting adhesive layer, 3... Nickel thin wire, 3a... Tip, 4... Wiring board, 4p, 5p... - Ponding pad, 5... IC chip, 11... Base material rubber sheet, 13... Copper thin wire, 14... Covering layer. Figure 1 Figure 3 (α) Figure 2 Figure 3 (b)

Claims (4)

[Claims] (1) An insulating film and a large number of conductive thin wires embedded in the film at predetermined intervals in the thickness direction so that both ends slightly protrude; An anisotropic conductive film characterized by comprising an adhesive means. (2) The anisotropic conductive film according to claim (1), wherein the film is an elastic body. (3) The adhesive means is an adhesive layer applied to both sides of the film,
The anisotropic conductive film according to item 1) or item (2). (4) A patent claim characterized in that the adhesive means is made of a metal, an alloy, or a metal compound that forms an alloy with the wiring pattern to be connected, at least on the surface of both ends of the conductive thin wire. Scope of paragraph (1) or (2)
The anisotropic conductive film described in .