JPH0451476A - Electrical coupling sheet and its electrical connection method - Google Patents

Abstract

PURPOSE:To provide the reliance on inter-terminal connections, enhance the bond strength, and increase the electric resistance by furnishing a number of small through holes in a heat resistant resin tape, and embedding in the through holes a binder containing flux components and solder particles included in the binder. CONSTITUTION:A number of small through holes 12 as penetrating in any way are furnished regardless of the bond terminal position for joining with a heat resistant resin tape 1 such as polyimide film, while low melting point solder particles 3 as electroconductive particulates are included in an insulative flux binder 4 containing flux components. and this flux binder 4 is embedded in the through holes 2 in the resin tape 1. This embedment is conducted through a printing process consisting of kneading the solder particles 3 and flux binder 4 together to form a binding agent, placing it upon the resin tape 1 on a working table 6, and moving a squeegee 5 in the A-direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrical connection sheet for electrically connecting mutually opposing connection terminals and an electrical connection method thereof.

[Prior Art] Conventionally, various members and methods for electrically connecting connecting terminals arranged apart from each other are known.

The most common type of connection is solder, but anisotropic conductive adhesives can be used to meet the needs for finer pitches of connection terminals. The anisotropically conductive adhesive is a mixture of conductive particles dispersed in an insulating resin binder. When using this anisotropic conductive adhesive to electrically connect the connecting terminals of mutual boards, the anisotropic conductive adhesive is interposed between the connecting terminals and they are bonded under heat, and the heat binds the insulating resin binder. Electrical connection is achieved by softening the conductive particles and bringing them into direct contact with opposing connection terminals under pressure, while also physically adhering them using the softened insulating resin binder. Desirably, when bonded with an anisotropic conductive adhesive, the material exhibits electrical conductivity in the thickness direction but insulating property in the surface direction, and thus has directionality of electrical conductivity.

As mentioned above, it is an absolute condition for an anisotropically conductive adhesive to exhibit conductivity in the thickness direction and insulation in the surface direction, and in order to exhibit conductivity in the thickness direction, A minimum of - conductive particles must be interposed between the connecting terminals of each substrate, and in order to exhibit insulating properties in the plane direction, adjacent conductive particles must be spaced apart so that they are not electrically conductive. It is essential that the

[Problems to be Solved by the Invention] However, since the anisotropic conductive adhesive simply has conductive fine particles dispersed and mixed into an insulating resin binder, it is difficult to uniformly disperse the conductive fine particles, and it is difficult to uniformly disperse the conductive fine particles. Since the spacing cannot be made constant, dense portions and sparse portions of conductive fine particles are formed. During thermocompression bonding, conductive particles connect surfaces that cannot be electrically connected in the dense areas, and insulating resin binders between the conductive particles in the sparse areas make it difficult to conduct in the thickness direction. Even so, it had the disadvantage of increasing electrical resistance. Therefore, even if a film of anisotropically conductive adhesive having a uniform thickness is applied, there are drawbacks such as unstable conduction and insufficient adhesive strength due to the presence of conductive particles. Furthermore, there was a drawback that it was difficult to reproduce these.

This invention was made in view of the above-mentioned circumstances, and its purpose is to improve the unstable reliability of connections between connecting terminals, insufficient bonding strength, and increased electrical resistance. An object of the present invention is to provide an electrically connecting sheet and an electrically connecting method thereof.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides an electrically bonding sheet in which a heat-resistant resin tape is provided with a large number of fine through holes, and each through hole is filled with a binder containing a flux component. It is constructed by embedding solder particles mixed therewith.

In addition, the electrical connection method is such that the above-mentioned electrical coupling sheet is placed between the connection terminals of opposing circuit boards, electronic components, etc., and solder particles in the through holes are melted by thermocompression bonding to connect the upper and lower connection terminals. Its purpose is to provide electrical continuity and bonding.

[Function] According to the electrical bonding sheet of the present invention, by embedding solder particles mixed with a binder containing a flux component into a large number of fine through-holes of a heat-resistant resin tape, the solder particles are mixed with a binder containing a flux component. Stable conductivity in the thickness direction is ensured without being affected by the density of the through-hole, and the through-hole wall exhibits reliable insulation in the planar direction.

Furthermore, according to the electrical connection method using an electrical coupling sheet, the J-type electrical coupling sheet is placed between connection terminals of a circuit board, electronic components, etc., and solder particles are melted by thermocompression bonding. , solder between the connection terminals. Therefore, soldering has a low resistance value due to bonding, and it is possible to achieve stable conduction and reliable insulation in the plane direction.
This increases the reliability of the bond.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the manufacturing process of an electrically bonding sheet. First of all,
Regardless of the position of the bonding terminal to be bonded to the heat-resistant resin tape l such as a polyimide film, a large number of fine through-holes 2 are provided arbitrarily, and the low melting point solder particles 3, which are conductive fine particles, contain a flux component. The flux binder 4 is mixed with an insulating flux binder 4, and the flux binder 4 is embedded in the through hole 2 of the resin tape 1.

In order to embed the solder particles 3 and the flags/hainder 4 in the through hole 2, the solder particles 3 and the flux spider 4 are kneaded to form a binder, and this binder is applied to the workbench 6.
1-, the squeegee 5 mounted on the resin tape l is moved in the direction of arrow A. A so-called printing method may be used.

Through this operation, the flux binder 4 is pushed into each through hole 2 together with the solder particles 3 and filled. The binder is preferably a hot-melt type made of thermoplastic resin, but is not limited to this.
It may also be made of a thermosetting resin that hardens after being melted.

Next, with reference to FIGS. 2 and 3, a specific example of an electrical connection method in which the above-mentioned electrical connection sheet is applied between a circuit board and a film board, or between connection terminals of electronic components will be explained. do.

Fig. 2 is a cross-sectional view of the state before electrical connection between the connection terminals of the circuit board and the film board using the air-bacteria binding sheet, and Fig. 3 is a cross-sectional view of the electrical connection state. . In this figure, 11 is a circuit board, 13 is a connection terminal thereof, 12 is a film circuit board, 1
4 is its connection terminal. Solder plating 15 is applied to these connection terminals J3.14 in advance. As shown in Figure 2,
Between the opposing surfaces of the circuit board 11 and the film circuit board 12.
The two-part electrically bonding sheet is placed and bonded under heat and pressure in the direction of arrow P, as shown in FIG. As a result, the solder particles 3 mixed in the flux binder 4 containing the flux component embedded in the through-hole 2 of the heat-resistant resin tape l and the solder plating 15 plated on each connection terminal 13, 14 are melted. Connecting terminal 13.1 due to surface tension
4 and solder plating 15 are coupled to establish electrical continuity. The thermocompression bonding may be performed using a thermocompression bonding head, or may be performed by reflow using a heat light source.

In the case of reflow, the crimp force may be the weight of the circuit board itself.

In this case, each connection terminal 13.14 has a bottom plating 15.
Since this is applied, the semi-[■] particles 3 and the solder plating 15 are reliably soldered by the action of surface tension. Also,
Since the flux binder 4 contains a flux component, oxidation prevention is achieved. Furthermore, since this connection is made by semi-IJJ connection, the resistance between the connection terminals 13 and 14 is small and the conduction is stable.

FIG. 2 is an enlarged cross-sectional view of a main part showing a method of electrically connecting connecting terminals that are mated together; FIG. 2 is a cross-sectional view of a state before joining, and FIG.
The figure is a cross-sectional view of the bonded state.

[Effects of the Invention] As explained in detail below, according to the present invention, a heat-resistant resin tape for electrical connection in which a flux binder mixed with solder particles is embedded in a large number of fine through holes of a heat-resistant resin tape. Since it is a sheet, it exhibits insulating properties in the plane direction by thermocompression bonding, and reliable conductivity in the thickness direction, making it possible to obtain stable conductivity with a low resistance value and reliability due to this. Even if the pitch of the connecting terminals that are joined to each other is much smaller than conventionally, highly reliable electrical coupling can be achieved.

l...Resin tape, 2...Through hole, 3
... Solder particles, 4 ... Flux binder, 11 ... Circuit board, 12 ...
Film circuit board, 13.14... Connection terminal,
15...Metsuki Handa.

Claims (1)

[Claims] 1) A binder made of a binder containing a flux component mixed with solder particles is embedded in each of a large number of fine through holes provided on the front and back surfaces of the heat-resistant resin tape. An electrical coupling sheet characterized by comprising: 2) An electrically bonding sheet in which solder particles are embedded together with a binder containing a flux component into a large number of fine through holes provided on the front and back surfaces of a heat-resistant resin tape.
It is characterized in that it is placed between the connecting terminals of circuit boards, electronic components, etc. that are placed opposite each other, and the solder particles in the through hole are melted by thermocompression bonding to make both the connecting terminals electrically conductive and join them. A method for electrically connecting an electrically bonding sheet.