JPH041476B2 - - 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 made of 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 conductive particles and conductive short fibers have the same particle size or the same length. Among the conductive particles or conductive fibers interposed between the opposing terminals, conductive particles with large particles or conductive fibers with the smallest content in the particle size or length distribution, or with long lengths, The distance is regulated, and conduction is obtained only by particles with large (long) diameter or length, and ±σ accounts for the majority of the particle size distribution.
Since the conductive particles or conductive fibers in the range of As a result, the connection method described above does not increase the packaging density.
It is unsuitable for small-space terminal arrangement, and since there is a difference in thermal expansion between the solidified organic polymer matrix and the conductive particles or conductive short fibers contained therein, the contact state is difficult to resist thermal changes. The electrical connection was extremely unstable and the reliability of the electrical connection was low.

The present invention relates to a new and improved electrical connection structure proposed to solve these disadvantages and shortcomings, and this invention relates to a new and improved electrical connection structure that uses an adhesive to connect connection terminals on a circuit board and/or between connection terminals of components. A connection structure formed by electrically connecting through an anisotropic conductive layer formed by dispersing and blending conductive powder in an organic polymer matrix in an amount of 0.05 to 40 parts by volume per 100 parts of the matrix. , the connecting terminal electrode of at least one of the connecting terminal portions is made of a material having a thermal transformation point of 250° C. or lower and has a conductive coating layer such as metal foil, and the conductive powder is applied to the corresponding part of the terminal. The present invention also provides a connection method for obtaining the electrical connection structure as described above, which includes at least the following: The terminals of one connection terminal part are made of a material with a conductive coating layer and a thermal transformation point of 250°C or less. Organic polymer matrix 100
A film-like or sheet-like molded body of an insulating material made by dispersing and blending 0.05 to 40 parts by volume of conductive powder with respect to the volume part is arranged, and the temperature between the connecting terminal parts is kept at 250°C.
The matrix is made to plastically flow by applying pressure at the following temperature, and the conductive powder is bitten into a material having a thermal transformation point constituting the terminal, and then cooled and solidified. be.

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 conductive paths is provided on the surface of the component, 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 is made of a material having a thermal transformation point of 250°C or less and having a conductive coating foil. Examples of materials that have this thermal transformation point include tin (melting point 232°C),
Conductive pastes, conductive inks, conductive paints, and conductive adhesives that are filled with low-melting point metals or alloys such as solder (melting point 183°C), conductive granules such as metal powder, carbon black, and graphite. Examples of the layer (foil) covering the material having this thermal transformation point include a foil made of a member constituting a conventionally known terminal, such as (c-1) carbon layer, copper, Metal foils such as aluminum, nickel, and gold, (c-2) epoxy resins, polyamide resins, diallyl phthalate resins,
An isotropic conductive film or (c-3 ) This film or foil is made of a film or foil plated with a precious metal or the like as required, but in any case, this foil is made of a conductive material dispersed in an adhesive organic polymer matrix, which will be described later. It is said to be to the extent that it can be eaten away by powdery particles.

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 100μm or more, it has a dielectric strength of 2000MΩ for 1 minute when DC500V 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,
Dispersed particles of single conductive metal compounds such as titanium carbide and nickel carbonyl, or the above-mentioned metal powders and carbon racks are used as conductivity imparting agents, and these are used as thermosetting resin matrices or high melting point thermoplastics. Dispersed in a resin matrix, such as phenolic resin, epoxy resin, silicone resin, or modified resin thereof, 6-6 nylon, polyethylene terephthalate, polyamideimide, polycarbonate, polyacetal, polyether, polyarylate, polyacrylonitrile, etc., and its specific resistance 10 ^-4 ~10 ² Ω・
After forming a molded body with conductivity of 0.5 cm, this is crushed into powder or granules, or powders of conductive organometallic compounds, conductive organic polymer substances, and other artificial graphite. ~2000μm particle size, e.g. 400 mesh pass average particle size 7μm, 1μm
m~325 mesh pass average particle diameter 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 connection 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 swell or swell 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 conductive particles when heating and pressurizing to obtain a connected structure, making it difficult to maintain insulation between adjacent terminals. It is something that

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.

Detailed embodiments of the present invention will be described below based on the accompanying drawings.

FIG. 1 shows a perspective view of two objects to be connected before they are connected. FIG. 2 is a partially cutaway sectional view taken along a direction orthogonal to the parallel conductive paths of the electrical connection body, showing another representative embodiment of the present invention in which these connected bodies are integrated by adhesive bonding. , 1 in the figure
0 is the drawer connection terminal part of the printed circuit board,
Reference numeral 20 is a connection terminal portion of a rigid printed circuit board, and reference numeral 30 is a small piece formed into a sheet shape using an adhesive organic polymer material.

The printed circuit boards 11 and 21 in FIG. 1 are made of a hard synthetic resin substrate made of phenol or the like with a thickness of 1.6 mm, and have a conductive coating foil 12a such as a metal foil such as a copper foil on the surface of the substrate. The terminals 12 and 22 are arranged parallel to each other and are made of a material having a dot, for example, conductive paste 12b, and the terminals 22b on the printed circuit board 21 in FIG. 2 are entirely conductive. The lead terminal 12 on the printed circuit board 11 has the same two-layer coating structure as in FIG. 1. Therefore, the connecting terminal 12 has a property that its coating film is easily eaten away by conductive particles. To obtain the electrical connection structure shown in FIG. 1, from the state shown in FIG. A metal hot bar (trowel) heated to around 250° C. is pressed onto the back side of the connection terminal portion 20 of. At this time, the hot bar is preferably pressed with a silicone rubber sheet having a hardness (JIS K 6301) of 20 to 70 and a thickness of 50 to 500 μm, which has excellent thermal conductivity, interposed therebetween, and the heat of the hot bar makes it conductive. A small piece 30 made of an adhesive organic polymer matrix in which powder and granules are dispersed plastically flows between the connecting terminals 12.
The conductive powder 32 densely filled in the gaps between the connecting terminals 22 and the organic polymer matrix 31 is applied to the connecting terminal electrodes 12 facing each other under the pressure of the trowel. At this time, the circuit board 21 and its connection terminals 22 press and move the conductive powder without deforming due to their rigidity, bite into the connection terminals 12 and 22, and form powder particles with a small diameter. until the opposite connection terminals 12,
Since it is involved in the conduction of 22, the conductive powder 32
Even though the particle sizes of the conductive powder particles are uneven, more conductive powder particles can be involved in the electrical connection between the opposing connection terminals 12 and 22.

Press the heated iron as above,
If plastic flow of the adhesive organic polymer matrix is confirmed after a certain period of time has elapsed, 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. I can do it.

FIG. 3 shows still another embodiment, in which a carbon layer or a copper foil 12a is placed on a lead terminal electrode 12b made of conductive paste or ink on a flexible substrate 11 made of a polyester sheet or the like. A flexible printed circuit board having a connecting terminal section 10 provided with a flexible printed circuit board and a flexible connecting terminal 22 made of a metal foil such as copper foil that can be easily deformed on a flexible board made of polyimide or the like. This is a connection structure with the connection terminal section 20 of the printed circuit board 21.

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. A connection structure in which electrical connection is made through a layer of an insulating material made of Because it is embedded in a material that has the following thermal transformation point, even if the conductive powder particles have different particle sizes, more conductive particles can be absorbed into the electrically conductive powder. Its practical value is great, since it can be involved in the connection and thus achieve a higher connection density and therefore more reliable electrical connection.

[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 another embodiment. FIG. 3 is a partially cutaway cross-sectional view taken along a direction perpendicular to the parallel conductive paths after connection, and FIG. 3 is a cross-sectional view of other different representative embodiments of the connection structure according to the present invention. 10, 20... Connection terminal portion, 11, 21... Substrate, 12a... Conductive covering foil, 12b... Particles made of a material having a thermal transformation point, 12, 22...
Connection terminal, 30...Adhesive organic polymer molded body, 3
1... Organic polymer matrix, 32... Conductive powder.

Claims (1)

[Claims] 1. Connecting terminals on a circuit board and/or between connecting terminals of components in an adhesive organic polymer matrix in an amount of 0.05 to 40% per 100 parts by volume of the matrix.
A connection structure in which electrical connection is made through an anisotropic conductive layer formed by dispersing and blending conductive powder of a capacitive part, and at least one of the connection terminal electrodes of the connection terminal part is made of a metal foil or the like. has a conductive coating layer of
Constructed of a material with a thermal transformation point of 250℃ or less,
An electrical connection structure characterized in that the conductive powder is embedded in a material having the thermal transformation point of the terminal. 2. Between opposing connecting terminal portions of a circuit board and/or component in which the terminal of at least one connecting terminal portion is made of a material having a conductive coating layer and a thermal transformation point of 250°C or less, A film-like or sheet-like molded body of an insulating material made by dispersing 0.05 to 40 parts by volume of conductive powder in 100 parts by volume of an adhesive organic polymer matrix is arranged, and a distance of 250 parts between the connection terminals is arranged. An electrical device characterized in that the matrix is made to plastically flow by pressurizing it at a temperature of 0.degree. Connection method.