JPH0226346B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new and improved electrical connection structure and method of connection thereof.

Traditionally, it has been used to connect the opposing drawer connection terminals of at least two printed circuit boards of the same or different types, or to connect the connection terminals of a flat wire cable opposite the connection terminals of the printed circuit boards. One method is to create a layer of an adhesive organic polymer matrix containing various conductive particles and short conductive fibers (generally oriented) dispersed between opposing connection terminals consisting of parallel conductive paths. There are known methods and structures for adhesively connecting the two.

However, it is virtually impossible to make all of the above-mentioned conductive particles and conductive short fibers have the same particle size or the same length. Among the conductive particles or conductive fibers interposed between them, those with large particle sizes or long ones that belong to the smallest content in the particle size or length distribution are used to connect opposing terminals. The distance is regulated, and conduction is obtained only by particles with a large (long) diameter or length, and ±σ accounts for the majority of the particle size distribution.
Conductive particles or conductive fibers in the range of A highly reliable electrical connection cannot be obtained, and as a result, the above-mentioned connection method does not increase the packaging density, is not suitable for small-spaced terminal arrangements, and, moreover, the organic polymer matrix and the conductive particles contained therein after solidification cannot be obtained. In addition, since there is a difference in thermal expansion between the conductive short fibers, the contact state is extremely unstable against thermal changes, and the reliability of electrical connection is low.

The present invention relates to a new and improved electrical connection structure proposed to overcome these disadvantages and drawbacks. Connect the connection terminals on the circuit board and/or between the connection terminals of the components.
A connection structure in which 0.05 to 40 parts by volume of conductive powder is dispersed in an adhesive organic polymer matrix and electrically connected via an anisotropic conductor layer, which is made by dispersing 0.05 to 40 parts by volume of conductive powder per 100 parts by volume of the matrix. Heat the surface of at least one of the connection terminals above to 250℃.
Consisting of a material with the following thermal transformation point,
The present invention is characterized in that the above-mentioned conductive powder is embedded in the above-mentioned material, and the present invention also provides a connection method for obtaining the above-mentioned electrical connection structure. between the connecting terminal portions of opposing circuit boards and/or components, where the terminal surface of at least one of the connecting terminal portions is made of a material having a thermal transformation point of 250°C or less,
A film or sheet-like molded product made by dispersing 0.05 to 40 parts by volume of conductive powder per 100 parts by volume of the matrix in an adhesive organic polymer matrix is placed, and the temperature between the connecting terminals is kept at 250°C. The matrix is made to plastically flow by applying pressure at a temperature of:
The method is characterized in that the conductive powder is bitten into at least the back surface of the terminal and then cooled and solidified.

The present invention will be described in detail below.The connection structure of the present invention is applicable not only to connections between opposing printed circuit boards of the same or different types, but also to connections between various circuit components to each of these printed circuit boards, as well as connections between these components. In particular, the parts referred to in the present invention include IC packages, IC carriers,
In addition to various other semiconductor devices or elements, so-called circuit parts such as ceramic elements, and circuit elements, various display devices or elements such as liquid crystal, EL, and LED, and even flat wire cables are included. This includes both those in which a lead-out connection terminal portion consisting of parallel conductor paths is provided on the surface of the device, and so-called terminal-containing components having a plurality of lead wires or lead terminals.

First, in the present invention, at least one of the drawer connection terminals on various printed circuit boards and/or the connection terminals of components must be made of a material having a thermal transformation point of 250°C or less on at least the surface thereof. These include, for example, low melting point metals or alloys such as tin (melting point 232°C), solder (melting point 183°C), metal powder, carbon black,
A conductive paste containing conductive powder such as graphite as a filler, a conductive ink, a conductive paint, a conductive adhesive, or a conventionally known terminal member, such as (c-1) copper, aluminum Modified resins made by adding or combining phenolic resins, epoxy resins, polyamide resins, diallyl phthalate resins, polyimide resins, or other compounds compositely reinforced with metal foils such as , nickel, and fillers such as paper and glass fibers. or (c-2) a terminal obtained by etching a laminated resin plate of the above metal foil and a film of triazine resin, polyimide, polyethylene terephthalate, etc. ,
Or (c-3) If necessary, add gold to this terminal.
In addition to terminals plated with precious metals such as platinum, (c-4)
A terminal obtained by vapor-depositing aluminum, copper, etc. on the laminated resin plate and etching it, or (c-
5) This terminal is formed by plating the same as above, and the surface thereof is coated with the above-mentioned material.

When the above connection terminals are normally arranged closely parallel to the surface of a circuit board or component and bonded and connected all at once, the thickness of the connection terminals is at least 2 to 2 mm.
It is sufficient if it is 3 μm or more, and if it is made of a coating film or copper foil, etc. and has a thickness of 10 to 40 μm,
If the adjacent gap is 100 μm or more, it will have an insulating force of 2000 MΩ for 1 minute when DC 500 V is applied.

On the other hand, the adhesive organic polymer matrix in the present invention is made of, for example, polyamide, polyethylene,
Polypropylene, polyvinyl acetate, polymethyl methacrylate, polyester, polyurethane,
Or co-blending, copolymerization, or epoxy resin, phenolic resin, urethane resin, uncured nitrile rubber, uncured butyl rubber, uncured chloroprene rubber, uncured silicone rubber, or these thermoplastic resins, thermosetting resins, rubber-like body etc. 2
A curing agent, a crosslinking agent, an auxiliary agent thereof, which is selected as a form of a hot melt adhesive composition, a pressure-sensitive adhesive composition, etc., containing at least one modified resin, etc., and added as necessary.
reinforcing fillers, pigments, stabilizers, titanium organic compounds,
Can contain coupling agents such as silane compounds, thickeners, etc., below 250°C, preferably between 250°C and 60°C
Plastic flow is assumed to occur within the range of .

The adhesive organic polymer matrix may include gold, silver, copper, aluminum, nickel, tungsten, titanium, cobalt or alloys containing these, tungsten carbide,
A mixture of dispersed particles of a single conductive metal compound such as titanium carbide and nickel carbonyl, or a thermosetting resin matrix or a high melting point thermoplastic resin using the above-mentioned metal powder or carbon black as a conductivity imparting agent. matrix,
For example, phenol resin, epoxy resin, silicone resin, or modified resin thereof, 6-6 nylon, polyethylene terephthalate, polyamideimide, polycarbonate, polyacetal, polyether, polyarylate, polyacrylonitrile, etc. are dispersed and blended, and the specific resistance is reduced to 10 ^{- 4} to 10 ²
After forming a molded body with conductivity of Ω/cm, it is crushed into powder and granules, as well as powder and granules of conductive organometallic compounds, conductive organic polymer substances, and other artificial graphite. From the particle size of 0.5 to 2000 μm, for example, 400 mesh pass average particle size of 7 μm,
A particle having an average particle diameter of 1 μm to 325 mesh passes of 10 μm is appropriately selected.

The conductive powder described above is appropriately selected and used depending on the dispersibility in the adhesive organic polymer matrix and the material of the adhesive terminal. Investigating the compatibility between the conductive powder and the adhesive organic polymer matrix in advance in a molten state of the matrix or in the state of a solution containing a solvent, so as not to melt or swell significantly in the molten state or solution state. It is desirable to take care to select combinations that have low affinity for each other.

Regarding the blending ratio of the conductive powder to the adhesive organic polymer matrix, the conductive powder may expand when the conductive powder is dispersed and blended.
The adhesive organic polymer matrix should be used to prevent it from melting and imparting conductivity to the adhesive organic polymer matrix itself (so as not to impair its insulation properties).
The amount of the conductive powder is 0.05 to 40 parts by volume, preferably 0.5 to 30 parts by volume, and more preferably 2 to 25 parts by volume per 100 parts by volume. The mixing ratio of the conductive powder can be reduced as the distribution ratio of the small particles increases, but if it is less than 0.05 part by volume, the conduction density of the connected structure will be low. connection becomes less reliable.
On the other hand, if the capacitance exceeds 40 parts, lateral chains tend to occur between the conductive particles when heating and pressurizing to obtain a connected structure, making it difficult to maintain insulation between adjacent terminals. It is based on

In the present invention, the adhesive organic polymer matrix in which the conductive particles are dispersed is usually formed into a film or sheet, or in the form of a coating on the surface of the connection terminal. is formed. This film-like or sheet-like molded product is produced by coating or topping a plastic film or sheet coated with a release agent or natural or synthetic paper with an adhesive organic polymer matrix in which conductive powder particles are dispersed. It can be easily obtained, and is usually cut into various shapes together with the release paper, and the release paper is peeled off before use. The thickness of the film-like or sheet-like molded product or coating film is larger than the maximum particle size of the conductive powder contained therein, and not more than 3 times the maximum particle size,
The thickness is preferably 2 times or less, and more preferably 1.5 times or less, but this is because if the thickness is too thick, the insulating matrix layer will easily flow out or protrude from the connection terminal part during hot pressing, resulting in poor connection. This is because there is a risk of reducing the number of conductive particles between the terminals.

Therefore, the film-like or sheet-like molded product or coating film made of the adhesive organic polymer matrix containing conductive powder or granules in the present invention can be heated at 250°C.
Below, preferably at a temperature of 60 to 250℃, 1 to 10
It is desirable that plastic flow occurs under a pressure of Kg/cm ² , and that the adhesive performance is in the most activated state.It is difficult to withstand a temperature test of about 70°C if it is lower than 60°C. In addition, if the temperature exceeds 250℃, the organic polymer matrix flowing from the connection part during connection work under heat and pressure is likely to be carbonized when exposed to air, and the electrical properties will deteriorate due to this carbide. This is because there is a risk of adversely affecting other electrical circuits, circuit elements, or parts arranged, and the above temperature range is preferably 75°C.
The temperature is preferably 100 to 220°C, more preferably 100 to 220°C.

The present invention will be explained below based on the additional drawings.

Fig. 1 shows a perspective view of two objects to be connected before they are connected, and Fig. 2 shows a view along the parallel conductive path of an electrical connection object of the present invention in which these objects to be connected are integrated by adhesive bonding. A partially cutaway enlarged cross-sectional view,
FIG. 3 is a partially cutaway enlarged sectional view taken along a direction perpendicular to the parallel conductive path, in which 10 is a lead-out connection terminal portion of a rigid printed circuit board, and 20 is a rigid printed circuit. This is a connection terminal portion of the substrate, and 30 is a small piece formed into a sheet shape with an adhesive organic polymer matrix in which conductive powder is dispersed.

Printed circuit board 1 in Figures 1 to 3
Nos. 1 and 21, for example, are made by dispersing and blending conductive powder or granules having a thermal transformation point of 250°C or less made of conductive paste or conductive ink on the surface of a rigid synthetic resin substrate such as phenol with a thickness of 1.6 mm. The connection terminals 12 and 22 are arranged parallel to each other and made of an adhesive organic polymer matrix, and therefore, these connection terminals 12 and 22 can be easily deformed by heat. In order to obtain the electrical connection structure shown in FIGS. 1 to 3, from the state shown in FIG. Then, a metal hot bar (trowel) heated to about 250° C. is pressed against the back side of the connection terminal portion 20 of the circuit board. In this case, the hot bar has a hardness of 20 to 70 (JIS K 6301) with excellent thermal conductivity and a thickness of 50 to 500 μm.
The small piece 30 made of the adhesive organic polymer matrix in which the conductive powder is dispersed is plastically fluidized by the heat of the hot bar, as shown in FIG. As shown, between the connection terminals 12 and the opposite connection terminal 2
The conductive powder 32 that is densely filled in the gap between the two and dispersed in the organic polymer matrix 31 is heated between the connecting terminal electrodes 12 and 22 facing each other under the pressure of the trowel. At this time, the circuit board 21 and its connecting terminals 22 do not deform due to their rigidity, and press and move the conductive powder, bite into the connecting terminals 12, 22, and even particles with small diameter
Since the conductive powder 32 is involved in the conduction between the opposing connection terminals 12 and 22, even though the particle diameters of the conductive powder 32 are uneven, more of the conductive powder is connected between the opposing connection terminals 12 and 22. Can be involved in electrical connections.

Press the heated iron as above,
After confirming the plastic flow of the adhesive organic polymer matrix after a certain period of time, the trowel may be removed, and the adhesive organic polymer matrix is cooled and hardened to obtain the electrical connection structure of the present invention. Can be done.

FIG. 4 shows another embodiment of the electrical connection structure of the present invention, which also includes a rigid substrate 1.
1, a conductive paste or ink coating 1
Output terminal electrode 12 made of copper foil or the like having 2a
Connecting terminal section 10 of a printed circuit board provided with b
and a connecting terminal portion 20 of a printed circuit board 21 which is formed by printing and molding a connecting terminal electrode 22b made of conductive ink on a flexible film. More of the conductive powder 32 bites into both of the opposing connection terminal electrodes 12b, 22b to achieve electrical connection.

FIG. 5 shows still another embodiment, which is a flexible printed circuit board in which a lead terminal electrode 12b made of conductive paste or ink is provided on a flexible substrate 11 made of a polyester sheet or the like. This is a connection structure between the connecting terminal portion 10 of the flexible printed circuit board 21 and the connecting terminal 20 of a flexible printed circuit board 21 in which a flexible connecting terminal 22 made of copper foil or the like is provided on a flexible substrate made of polyimide or the like.

As explained above, the connection structure and connection method of the present invention include dispersing and blending conductive powder in an adhesive organic polymer matrix between connection terminals on a printed circuit board and/or between connection terminals of components. In the connection structure formed by electrically connecting through a layer of an insulating material, the conductive powder is embedded into the surface of the opposing connection terminal electrode. Even if the particles have different particle sizes, more particles can be involved in the electrical connection, resulting in a higher connection density and therefore a more reliable electrical connection. Since it can be achieved, its practical value is enormous.

[Brief explanation of drawings]

1 to 3 show typical embodiments of the connection structure according to the present invention, in which FIG. 1 is a perspective view of two connected objects before connection, and FIG. 2 is a perspective view of two connected objects after connection. Partially cutaway enlarged sectional view along the parallel conductive path, 3rd
The figure is a partially cutaway cross-sectional view along a direction perpendicular to the parallel conductive paths. FIGS. 4 and 5 are cross-sectional views of other different representative embodiments of the connection structure according to the present invention. 10, 20... Connection terminal portion, 11, 21... Substrate, 12, 22... Connection terminal, 30... Adhesive organic polymer molded body, 31... Organic polymer matrix, 32... Conductive powder particles body.

Claims (1)

[Claims] 1. Connecting terminals on circuit boards and/or connecting terminals of components facing each other in an adhesive organic polymer matrix containing 0.05 to 40 parts by volume per 100 parts by volume of the matrix. A connection structure in which electrical connection is made through an anisotropic conductor layer made by dispersing and blending conductive powder, and the surface of at least one of the connection terminals is heated to a temperature of 250°C or less. 1. An electrical connection structure characterized in that the structure is made of a material having a transformation point, and the conductive powder is embedded in the material. 2. Touch the surface of the terminal of at least one of the connection terminals.
100 parts by volume of the matrix in an adhesive organic polymer matrix between the connecting terminals of opposing circuit boards and/or components made of a material having a thermal transformation point of 250°C or less. Against
A film or sheet-like molded body made by dispersing 0.05 to 40 parts by volume of conductive powder or granules is arranged, and pressure is applied between the connecting terminals at a temperature of 250°C or less to cause the matrix to plastically flow, An electrical connection method characterized in that the conductive powder is bitten into at least the back surface of the terminal and then cooled and solidified.