JPS62165886A - Jointing member of circuiy - 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 [Field of Industrial Application] The present invention relates to a conductive connecting member used for connecting circuits.

[Conventional technology]

Soldering has traditionally been used as a connection method when connecting terminals are lined up at a fine pitch, such as connecting integrated circuits to wiring boards, connecting display elements to wiring boards, and connecting electrical circuits to leads. Methods using conductive adhesives and conductive adhesives are widely used. However, in these methods &
Since the connecting member must be formed only in the conductive circuit portion, it has been difficult to connect fine circuits that are becoming increasingly dense and precise.

Recently, improvements have been made to connection members for circuit connections, and they have already been published in Japanese Patent Application Laid-Open No. 51-20941 and Japanese Patent Application Laid-Open No. 55-10.
This method has been proposed in Japanese Patent Application Laid-Open No. 4007, Japanese Patent Application Laid-Open No. 56-122195, Japanese Patent Application Laid-Open No. 51-21192, and the like.

The basic idea behind all of these is to provide an anisotropically conductive connecting member layer containing a conductive material between opposing circuits, and to apply pressure or heat and pressure means to generate electricity between the circuits. At the same time as the electrical connection, insulation is provided between adjacent circuits, and the kW of opposing circuits is fixed.

However, in such conventional methods, conduction between circuits is mainly obtained by contact between a plurality of conductive materials, often metal particles, and the metal particles are directly connected.

There was a lack of reliability in conduction between particles and particles.

In addition, JP-A-58-111202 describes a connection material in which plastic containing a conductive filler is crushed into particles and used as conductive particles, but this method uses a large amount of plastic particles. The particles need to be filled with a conductive material, which makes the particles rigid, impairing Pusistek's original thermal softening and flexibility, and furthermore, the conductivity itself is low, making it difficult to achieve the high reliability that is the objective of the present invention. It is unsuitable as a sexual connection material.

The present inventors had previously proposed a conductive adhesive sheet with extremely good transparency for circuit connections, but as a result of intensive study on a method to improve the above-mentioned drawbacks and enable highly reliable connections, the present invention was developed. Achieved invention.

[Purpose of the invention]

It is an object of the present invention to provide a connecting member for connecting fine circuits, which is capable of obtaining an anisotropically conductive connection with excellent p-reliability through a simple bonding operation.

[Disclosure of the invention]

That is, the present invention provides a connecting member comprising an adhesive component and conductive particles, in which substantially the entire surface of a core material comprising thermosetting particles as conductive particles (hereinafter referred to as thermosetting core material) is coated with a gold R thin layer. Preferably, the laminated tetraelectric particles have an average particle diameter of 1 to 50 μm, and the ratio of the minimum diameter to the maximum diameter of the particles is 1 to 50 μm. is 0.5 to 1.0, K (1,1 to 10% by volume is present in the connecting member, and the total light transmittance is 4
This is a connecting member that has transparency of 0% or more and heat-sensitive adhesive properties.

In the connecting member according to the present invention, the metal tube coated with the thermosetting core material is heated or heated and pressurized at the time of connection.
Because the conductive particles come into contact with each other or with the conductive circuit to form a conductive path, it is possible to connect fine circuits with excellent reliability.Furthermore, the thermosetting core material can be used during connection operations by heating or heating and pressurizing. K. Due to its slight thermal softening property, it deforms so as to be pressed along the conductive circuit, and as a result, the coated metal has an increased contact area with the circuit, so that particularly excellent conductivity can be obtained. In addition, as conductive particles,
Since only a very small amount of gold 1 is required, it is possible to reduce the weight of the connecting member and save valuable metal resources.

Furthermore, since adhesives having heat-sensitive adhesion properties are resistant to heating or heating and pressure during connection, mechanical connections can be made at the same time in insulated circuit parts.

Furthermore, in the connecting member of the present invention, since the core of the conductor particles is a thermosetting resin, when heated or heated and pressurized during connection, the connecting member can be appropriately softened and deformed without completely flowing between the circuits. It is possible to maintain a large contact area with the

On the other hand, since no pressure is applied to the particles in the insulated circuit section between the circuits, sufficient P and R properties can be obtained with respect to the adjacent circuits.

To explain the structure of the connecting member according to the present invention in more detail with reference to the drawings, FIGS. 1 and 2 are schematic cross-sectional views showing conductive particles used in the present invention, and in FIG. This figure shows how the surface of the core material 1 is covered with the metal layer 2, and the thermosetting core material 1 has a hollow portion 5 in FIG.

The thermosetting core material of the present invention having the structure shown in FIG. 1 or 2 can be used alone or in combination.

Here, the core material can have various configurations, such as a completely filled body, a hollow body whose interior is made of gas, or a foam body containing some air bubbles inside.

Further, it is optimal that the core material 1 is entirely covered with gold JA 2, but there may be some unnucleated portion 6. The thermosetting core material 1 preferably has a spherical shape, but may have protrusions or irregularities on one surface. It can also be used as an aggregate of core material particles.

Examples of the thermosetting core material 1 used in the present invention include urea, ethylene-urea, melamine, pensoquanamine,
Phenol-formalin, resorcinol-formaldehyde, xylene.

Resins such as furan, diallyl phthalate, epoxy, polyisocyanate, polyimide, polyester, acrylic, benzimidazole% phenoxy, fluorine, and silicone are applicable, and the degree of curing is within the range that does not interfere with the production of the connecting member. Any single substance or a combination of two or more of these may be used. In addition, as a core material, single or composite materials such as reactive polymer blends, such as the above-mentioned resins such as epoxy resin and phenol-h resin, and synthetic rubbers such as nylon, polyamide, polyurethane rubber, and nitrile rubber, may be used. It is also possible to blend with

Furthermore, resins with self-type @Note or heavy functional groups such as carboxylic acid groups, epoxy groups, amino groups, and hydroxyl groups can be used alone or in combination, and in combination with crosslinking agents, curing agents, etc. You can also do it.

The metal 2 used for α is AI, Sb, and Be.

Bi, Cd, Ca, Cs, Cr, Co, C
u, Ce, Au, lr, Fe.

Pb, L4. Mg, Mn, Hg, Mo, N
i, Pd, Pt, K, Rh.

Se, Si, Ag, Na, Sr, Ta, S
n, TI, W, U, V+Y, Zn, Zr,
Conductive metals such as TI, As, In, and Lu can be used, and these metals may be used alone or as oxides, or in a combination of 281 or more, or as an alloy of two or more types.

Methods for forming gold Jf42 on the surface of the thermosetting core material 1 include, for example, physicochemical methods such as vapor deposition, sputtering, and plating, or using a small amount of gold PA' at the time of forming the thermosetting core material. The metal powder is dispersed in a monomer and adsorbed onto the surface of the polymer particles after polymerization, the metal is chemically bonded to the core material having functional i&, or the metal is adsorbed with a surface activator or a coupling agent, etc. The thickness of the exposed skin can be set arbitrarily.

Conventionally, such four-round particles have been made by providing thin holes such as Ag on glass spheres (beads) or glass hollow spheres (balloons), but these glass spheres or hollow spheres soften and deform when heated and pressurized. Therefore, it is not suitable for implementing the present invention.

The conductive particles obtained above have an average particle size of 1 to 50μ
m, the ratio of the minimum diameter to the maximum diameter of the particles is 0.5 to 1.
Assume that it is 0. When the particle size is 1 μm or less, a large amount of conductive particles is required, and as a result, the amount of packed particles increases, resulting in a large decrease in adhesive strength, and when the particle size is 50 μm or more,
This is not preferable because the particles are large and cause electrical conduction between adjacent circuits (space parts).

Regarding the shape of the tetraelectric particles, as mentioned above, the ratio of the minimum diameter to the maximum diameter (hereinafter, the particle size ratio is defined as 0.5 to 1.08 degrees. Outside this range, the particles become too flaky). , it becomes unsuitable for obtaining the electrical conductivity between circuits and the insulation between adjacent circuits, which are the objects of the present invention, and the connection between circuits lf.
There is also a strong tendency for t-notes to decrease. A typical example that satisfies this range is a spherical shape, but there is no particular limitation as long as it satisfies the above conditions. Further, the particle surface may have protrusions or irregularities. Further, the particles are not limited to single particles, but may be particles made of aggregates.

Further, the particle size is assumed to be the overall average particle size, and it is convenient to measure the particle shape and particle size using, for example, a scanning electron microscope.

When the conductive particles are spherical, it is easy to obtain contact between the particles or between the particles and the circuit surface by applying heat and pressure during connection, and it is easy to obtain high conductivity.

The conductive particles may exist in a single layer in the thickness direction of the connection member, or may have a structure in which a plurality of conductive particles are arranged in the thickness direction.

The majority of the 4-carbon particles in the adhesive are 0.1 to 10% by volume. If it is less than 0.1% by volume, satisfactory conductivity cannot be obtained, and if it is more than 10% by volume, the insulation with adjacent circuits decreases and transparency of the connecting member cannot be obtained.

As the adhesive used in the present invention, basically any formulation used in ordinary adhesive sheets exhibiting insulation properties can be used. The formulation used for ordinary sliding sheets consists of a polymer that imparts cohesive force, and other components such as tackifiers, tackifiers, crosslinkers, anti-aging agents, and dispersants, which are used as required.

These polymers include ethylene vinyl acetate copolymer, ethylene-vinyl acetate copolymer IU, polyethylene, ethylene-propylene copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene - Acrylate copolymer, acrylic ester rubber, polyinobutylene, atactic polypropylene, polyvinyl butyral, acryl-nitrile-butadiene copolymer, styrene-butadiene block copolymer, styrene-yne 7' Synthetic rubbers such as Renblock copolymer, polybutadiene, ethylene cellulose, polyester, epoxy, polyamide, polyurethane, natural rubber, silicone rubber, polychloroprene, polyvinyl ether, etc. can be used alone or as a Two or more types are used in combination.

As a tackifier, dicyclopentadiene 4t4 fat,
Rosin, modified rosin, terpene resin, xylene ff4
There are resins, terpene-phenol resins, alcohol-based phenol resins, coumaron-indene resins, etc., and these may be used alone or in combination of two or more, if necessary. Typical tackiness modifiers include various plasticizers such as dioctyl phthalate.

Crosslinking agents are used when it is necessary to increase the cohesive force of polymers, and are polyfunctional substances that react with the functional groups of polymers, such as polyisocyanates, melamine resins, urea@fats, phenolic resins, etc. .

Antioxidants are used when it is necessary to increase the stability of the polymer binder against heat, oxygen, light, etc., and include stabilizers such as metal soaps and antioxidants such as alkylphenols. There are UV absorbers such as benzophenone type and benzotriazole type, and they can be used alone or in combination of two or more as necessary.
Ru.

A dispersant may be used to improve the dispersibility of conductive particles. Examples of this include surfactants, which can be used in combination of one or more of nonionic, cationic, anionic, and amphoteric surfactants.

The method of manufacturing the connecting member according to the present invention includes dissolving a conventional N agent composition consisting of a polymer and other additives used as necessary in a solvent, dispersing it in a suspension state in a medium, or dispersing it in a hot bath. After melting to a liquid state, conductive particles are mixed by a conventional method such as a ball mill to obtain a conductive particle mixed adhesive composition.

When using a solvent, conductive particles with a metal layer formed on a thermosetting core material have reduced solubility in solvents. Although it is possible to use a solvent, it is more preferable to select a solvent that completely melts the adhesive and does not dissolve the thermosetting core material. A good method for this purpose is, for example, to emulsify the adhesive and disperse the conductive particles in an aqueous medium.

Is the above conductive particle mixed adhesive applied to one or both circuits that require connection by means such as screen printing or roll coating? The connecting member N may be formed directly on the circuit using the above-mentioned method.

Further, a continuous elongated body of the connecting member may be provided on the circuit. In this case, in order to obtain a continuous long body of the connecting member, the connecting member layer may be formed by the above method on a separator made of paper or plastic film, which has been subjected to peeling treatment as necessary, and then rolled up. If the viscosity of the layers is low, it is also possible to overlap the layers without using a separator.

In the above manufacturing method, when the adhesive composition contains a bath agent or a dispersion medium, the volume shrinkage phenomenon in the thickness direction during drying of the solvent is fully utilized to obtain a connecting member in which the conductive particles are arranged more densely in the thickness direction. In addition, in hot-melt coating without a bath agent, environmental pollution caused by solvents during production can be prevented.

The thickness of the connecting member layer is relatively determined taking into account the particle size of the conductive particles and the characteristics of the connecting member, but it is between 5 and 100 μm.
A thickness of .

If the thickness is less than 5 um, optical adhesion cannot be obtained, and if it is 100 μm or more, a large amount of tetraelectric particles must be mixed in order to obtain sufficient conductivity, which is not practical.

The obtained connecting member surface may be covered with a separator to prevent the adhesion of dust, etc., if necessary, or it may be possible to continuously roll the material using a double-sided separator. The resulting connecting member has considerable transparency. When the connecting member is transparent, quality control during manufacturing is easy to perform and the appearance is good. In addition, when adhering display elements, etc., it becomes possible to adopt a configuration in which the adhesive body can be seen through.

A method for bonding a circuit using the obtained connecting member is, for example, by temporarily attaching a film-like connecting member to the circuit, and then peeling off the separator at the place where the separator is located, or applying a conductive adhesive composition. If necessary, the circuit 5 may be attached to the surface after removing the solvent using a hot press or a heated roll.

FIG. 5 and the fourth tooth schematically show the state in which the circuit is connected by the above method, and as the adhesive 4 softens and flows due to heat and pressure, the conductive particles 8 also soften and deform, and mutually interact with each other. Since the two circuits 5 and 6 are in contact with each other, conductive adhesion between the two circuits 5 and 6 becomes possible.

The sixth factor is an example where there are multiple or more layers of conductive particles 8 between the circuits 5 and 6, and the metal layers on the surface of the particles contact each other to form a conductive path. Notes are obtained.

During heating and pressurization during connection, the coating metal is a thin layer, so it can sufficiently follow the deformation of the PJ@-formable core material, and if it cannot follow the deformation, defects such as cracks will occur in the gold PA/Il. Even if this occurs, the conductive path can be maintained by contact with the circuit or other particles.

〔Example〕

The present invention will be explained in more detail below using examples.

Examples 1 to 6 (1) Epoxy resin spherical particles of which the surface of the connection member was coated with Au were coated with 100% of fake ethylene butadiene block copolymer (M12.6).
The samples were placed in an adhesive solution containing 40 parts of a terpene-based tackifier having a softening point of 120° C. and 200 parts of toluene using different inlaid plates.

The above handout was subjected to ultrasonic dispersion to obtain an adhesive solution containing conductive particles.

Coated on a separator (silicone-treated polyester film) with this MQk bar coater and heated at 100℃-5
After drying for a few minutes and removing the bath agent, a film-like connection member was obtained.

(2) Evaluation A flexible circuit board (FP) with a total circuit width of IQQmm and a circuit with a line width of one track (l1mm) and a pitch of 0.2[nLll].
C), 3 mm during adhesion, length 1 QQ mm [The cut connection member was placed and heated at 100°C - 10 kg/an'-s.
Temporary attachment was performed by heating and pressurizing for seconds to obtain an FPC with connection members.

Thereafter, the separator was completely peeled off, placed on another peeled FPCi separator having the same pitch, and the FPC circuit was aligned using a microscope, and the circuit was connected by heating and pressurizing at a pressure of 15 kg/an'' for 10 seconds. The contact layer temperature is as shown in Table 1 and was determined by adjusting the temperature of the hot plate of the press.In each example, the adhesive sheet was transparent. It was easy to set up.

The percentages are shown in Table 1, and each example shows good S.
a Shows low resistance and insulation from adjacent circuits. Good results were also obtained under a wide range of acceptance conditions.

Comparative Example 1 A connecting member was prepared and evaluated in the same manner as in Examples 1 to 6, but the amount of conductive particles in the foil was increased to 20 pieces and 8R%. in this case,
All first wins? The L pass rate decreased, it was difficult to position the circuit, and the insulation from adjacent circuits was insufficient.

Comparative Example 2 This was the same as Examples 1 to 6, but nickel particles with a particle size of 45 μm obtained by the atomization method were used as the conductive particles. In this case, although the initial resistance was good, a continuity failure occurred in the reliability test evaluation.

Example 7 Polyimide resin spherical particles coated with Ni on the surface were heated to thermoplastic polyester resin (molecular weight approximately 20.0OC1).
, a glass transition temperature of 7° C.) was dispersed and mixed in a 30% methyl ether ketone solution to prepare a total adhesive solution containing particles, and a film-like connecting member was obtained in the same manner as in Example 1''-6. Table 1 shows the results of evaluation after obtaining an FPC with a connecting member in the same manner as in Examples 1 to 6 and pasting it on transparent conductive glass having a circuit of the same pitch. .

Example 8 The four electric pole particle mixed adhesive solution obtained in Example 7 was applied on a separator (IK) onto the circuit of the FPC and dried to obtain an FPC with a connecting member.

Thereafter, in the same manner as in Example 7, a transparent glass electrode having a circuit of the same pitch was attached and the same evaluation was performed.Table 1 shows the results. As in Example 7, good initial customization and reliability were obtained.

In Table 1, (1) Continuity resistance is measured by using a multimeter to measure the resistance between opposing electrodes of two circuits connected by a connecting member (connection surface m
0.1mraX3m+n) (2) Insulation resistance is measured by measuring the resistance between adjacent circuits of two circuits connected by a connecting member using a high-megohmmeter (6) Reliability is measured by measuring the resistance between two circuits connected by a connecting member. The circuit t
--Thermal shock at 20° C. for 50 minutes/80° C. for 60 minutes was treated for 100 cycles, and the conduction resistance was then completely measured for evaluation.

(4) Total light transmittance was measured using Nippon Denshoku Korai (Aisaku Digital Turbidity Meter NDH-20) in accordance with JIS K-6714.
Measured by D.

〔Effect of the invention〕

As detailed above, the connecting member of the present invention uses conductive particles with a conductive metal thin layer formed on the surface of a thermosetting core material, thereby allowing a wide variety of circuit connection conditions.
) Connection workability has been improved, and resistance to temperature changes after connection has been significantly improved.

It also provides sufficient insulation from adjacent circuits, making it useful as a connecting material for fine circuits.Furthermore, since the connecting material is transparent, it is possible to align fine circuits with the help of transmitted light. It has the advantage of being easy to perform.

[Brief explanation of drawings]

Figures 1 and 2 show the cross-sections of conductive particles. FIG. 6 and FIG. 4 are schematic sectional views showing a state in which a circuit is connected using a connecting member according to the present invention. Explanation of symbols 1 Thermosetting core material 2 Metal 5 Hollow part 4 Adhesive 5 Circuit 6 Circuit 7 Insulating substrate 8411 Particulate Figure 4 Procedural Amendment (Spontaneous) Showa #. August 25, 1961

Claims (1)

[Claims] 1. In a circuit connecting member comprising an adhesive component and conductive particles, the conductive particles cover substantially the entire surface of a core material consisting of thermosetting resin particles with a thin metal layer. A connection member for a circuit, characterized in that it is made of particles. 2. The average particle diameter of the conductive particles is 1 to 50 μm, the ratio of the minimum diameter to the maximum diameter of the particles is 0.5 to 1.0, and the connecting member contains 0.1 to 10% by volume, and the total light beam Transmittance (
JIS K-6714) is 40% or more, the circuit connecting member according to claim 1. 3. The circuit connecting member according to claim 1 or 2, wherein the connecting member has heat-sensitive adhesion properties.