JPH1171560A - Anisotropically electroconductive adhesive material, and liquid crystal display and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject adhesive material causing no damage such as cracks even in case of the fine pitches of wiring electrodes, therefore causing no short-circuiting between adjacent electrode patterns, by dispersing electroconductive particles in a specific density in an electrical insulating adhesive. SOLUTION: This anisotropically electroconductive adhesive material is obtained by dispersing electroconductive particles 1 in a density of 300-650/mm<2> in an electrical insulating adhesive, wherein the electroconductive particles have the following characteristics: pref. 2-30 μm in average size, having a property as hard elastic balls under a compressive load of <=2 to 3 gf/particle at normal temperatures, and having such a property as to crush and cause plastic deformation at a point when the compressive load comes to a level of 2 to 3 gf/particle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of electrically connecting a plurality of substrates with their wiring patterns facing each other, and providing a conductive pattern between an external lead wiring electrode of one element substrate and a wiring electrode terminal of another device. The present invention relates to an anisotropic conductive adhesive used for a connection purpose, a liquid crystal display device, and a method for manufacturing a liquid crystal display device.

[0002]

2. Description of the Related Art Conventionally, for example, two wiring boards each having a wiring pattern formed on the surface thereof are bonded in a state where the wiring patterns of the respective boards face each other, and the wiring patterns on the same board are insulated and face each other. An anisotropic conductive adhesive (anisotropic conductive film) is used as an adhesive to secure electrical conductivity between wiring patterns (securing insulation in the horizontal direction and ensuring conductivity only in the vertical direction). Anisotropic conductive films). Such an anisotropic conductive adhesive (anisotropic anisotropic conductive adhesive) is an adhesive component having thermal adhesiveness and electrical insulation.
(Insulating adhesive; binder) Provided as a film in which conductive particles are dispersed. Specifically, when the anisotropic conductive adhesive (anisotropic conductive film; anisotropic conductive film) is sandwiched between two wiring boards and the two wiring boards are heated and pressed, the wiring pattern is formed. The insulating adhesive in the formed portion moves in the horizontal direction, and the wiring patterns facing each other on the two substrates are electrically connected by conductive particles in the vertical direction. Electrical connection can be secured. That is, anisotropic conductive bonding can be performed.

[0003]

However, in the conventional anisotropic conductive adhesive, for example, a wiring electrode for external drawing of a liquid crystal display element using a resin substrate and a flexible electrode for a predetermined device are used. In the case where the wiring electrode terminals are connected by thermocompression bonding, when the pitch of the wiring electrodes for external drawing of the liquid crystal display element is as fine as about 200 μm, there is a problem that good anisotropic conductive bonding may not be achieved. .

That is, when the pitch of the external lead-out wiring electrodes of the liquid crystal display element is as fine as, for example, about 200 μm, conventionally, the external lead-out wiring electrodes of the liquid crystal display element are not damaged by cracks or the like. In addition, there is no anisotropic conductive adhesive that does not cause a short circuit (conductive contact) between adjacent electrode patterns of the external lead wiring electrode of the liquid crystal display element.

According to the present invention, even when the pitch of the external lead-out wiring electrodes of the liquid crystal display element is as fine as about 200 μm, for example, the external lead-out wiring electrodes of the liquid crystal display element are not damaged such as cracks. And an anisotropic conductive adhesive material that does not cause short-circuit (conductive contact) between adjacent electrode patterns of external lead wiring electrodes of a liquid crystal display element, a liquid crystal display device, and a method of manufacturing a liquid crystal display device. The purpose is.

[0006]

To achieve the above object of the Invention The invention of Claim 1 wherein the conductive particles are in an insulating adhesive, the 300 / mm ² to 650 pieces / mm ² dispersion It is characterized by being dispersed by density.

According to a second aspect of the present invention, in the anisotropic conductive adhesive according to the first aspect, the average particle diameter of the conductive particles dispersed in the insulating adhesive is 2 μm to 30 μm.
Is within the range.

According to a third aspect of the present invention, in the anisotropic conductive adhesive according to the first or second aspect, the conductive particles have a compressive load of 2 gf / particle to 3 gf at room temperature.
/ Particles have the characteristics of hard elastic spheres, and have the characteristic of crushing and plastically deforming when the compression load reaches 2 gf / particles to 3 gf / particles.

According to a fourth aspect of the present invention, there is provided an anisotropically conductive adhesive according to any one of the first to third aspects, wherein a plurality of conductive layers are formed by using the anisotropically conductive adhesive. When a predetermined compressive load is applied to the anisotropic conductive adhesive between the conductive members for conductive bonding between the conductive members, irregularities on the surface of the conductive particles are interposed between the conductive particles and the conductive member. It is characterized in that it is formed to a sufficient degree to reach the conductive member without the insulating adhesive.

According to a fifth aspect of the present invention, there is provided an anisotropic conductive adhesive according to any one of the first to fourth aspects, wherein the anisotropic conductive adhesive is formed as a film-like film. In this case, the relationship between the particle diameter D of the conductive particles and the film thickness T of the insulating adhesive is D ≧ T.

According to a sixth aspect of the present invention, there is provided a liquid crystal display device using a resin substrate, wherein the external lead-out wiring electrode and the flexible wiring electrode terminal for a predetermined device are provided in any one of the first to fifth aspects. It is characterized in that it is connected by thermocompression bonding using the anisotropic conductive adhesive described in the item.

According to a seventh aspect of the present invention, in the liquid crystal display device of the sixth aspect, the pitch of the external lead wiring electrodes of the liquid crystal display element is 150 μm to 400 μm. .

The invention according to claim 8 is a thermocompression bonding method using an anisotropic conductive adhesive between an external lead wiring electrode of a liquid crystal display element using a resin substrate and a flexible wiring electrode terminal for a predetermined device. in the method for manufacturing a liquid crystal display device for manufacturing a liquid crystal display device are connected, the anisotropic conductive adhesive, in an insulating adhesive, 320 conductive particles having an average particle diameter of 20μm are / mm ² to 600 It is characterized in that those dispersed at a dispersion density of pcs / mm ² are used.

According to a ninth aspect of the present invention, in the method of manufacturing a liquid crystal display device according to the eighth aspect, the external lead-out wiring electrodes of the liquid crystal display element have a pitch of 150 μm to 40 μm.
It is characterized by having a thickness of 0 μm.

[0015] The invention according to claim 10 is the invention according to claim 8.
Alternatively, in the method for manufacturing a liquid crystal display device according to claim 9, when the thickness of the flexible wiring electrode terminal for the predetermined device is 18 μm, the anisotropic conductive adhesive includes:
Before the thermocompression connection, the insulating adhesive having a thickness T of 16 ± 3 μm is used.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a configuration example of the anisotropic conductive adhesive according to the present invention. In the example of FIG. 1, the anisotropic conductive adhesive 11 is configured as a film-like film (anisotropic conductive film, anisotropic conductive film). The conductive particles 1 are dispersed in the adhesive 12 at a predetermined ratio.

FIG. 2 is a diagram (cross-sectional view) showing a configuration example of the conductive particles 1 used for the anisotropic conductive adhesive 11. The conductive particles 1 are a core material particle 2 and a core material particle 2. And a conductive layer 3 formed on the surface of the substrate.

The conductive particles 1 are usually 2 to 50 μm.
m, preferably 5 to 30 μm, more preferably 20 μm
Average particle diameter (average diameter). Further, the CV value of the conductive particles 1 is preferably 20% or less, more preferably 15% or less. Here, the CV value is a value contained (dispersed) in the anisotropic conductive adhesive 11.
Ratio between the average value (average particle diameter) AV of the particle diameters of the conductive particles 1 and the standard deviation σ of the particle diameters of the conductive particles 1
(σ / AV), and the CV value of the conductive particles 1 contained in the anisotropic conductive adhesive 11 is preferably as small as possible. That is, the conductive particles 1 used for the anisotropic conductive adhesive 11 preferably have the same particle diameter as much as possible.

The conductive particles 1 have such a density that the anisotropic conductive adhesive 11 can exhibit the function as an anisotropic conductive adhesive (that is, the anisotropic conductive adhesive 11 is Using, for example, a wiring pattern of a predetermined pitch
When two wiring boards (conductive members) formed on the surface are bonded together with the wiring patterns (conductive members) of the respective boards facing each other, the wiring patterns on the same board are insulated from each other and Electrical conductivity between wiring patterns
(At such a density as to exhibit the function of ensuring insulation in the horizontal direction and ensuring conductivity only in the vertical direction) and is dispersed in the insulating adhesive 12.

More specifically, in the insulating adhesive 12 of the anisotropic conductive adhesive 11, the conductive particles 1 having the above-mentioned particle diameter are 300 to 650 particles / mm ² , preferably 320.
It is dispersed at a dispersion density of up to 600 particles / mm ² .

In particular, the anisotropic conductive adhesive 11 is used for thermocompression connection between a wiring electrode for external drawing of a liquid crystal display element using a resin substrate and a flexible wiring electrode terminal for a predetermined device, as described later. In the case, anisotropic conductive adhesive 1
It is preferable that the particle diameter of the conductive particles 1 used in Step 1 is about 20 μm and the dispersion density of the conductive particles 1 is about 320 to 600 particles / mm ² .

That is, the case where the anisotropic conductive adhesive 11 is used for thermocompression bonding between a wiring electrode for external drawing of a liquid crystal display element using a resin substrate and a flexible wiring electrode terminal for a predetermined device as described later. , Anisotropic conductive adhesive 1
The larger the particle size of the conductive particles 1 used for the electrode 1 is,
(For example, a wiring electrode for external drawing of a liquid crystal display element (ITO
The cracks in the electrodes) are unlikely to occur. However, if the particle size of the conductive particles 1 used for the anisotropic conductive adhesive 11 is too large, it is necessary to lower the dispersion density in order to prevent a short circuit between adjacent electrode patterns on the same substrate. When the dispersion density of the particles 1 is reduced, the number of the conductive particles 1 existing between the external lead-out wiring electrode of the liquid crystal display element using the resin substrate and the flexible wiring electrode terminal for the predetermined device is considerably varied. This makes it difficult to make uniform conductive adhesion between the external wiring electrode of the liquid crystal display element using the resin substrate and the flexible wiring electrode terminal for the predetermined device. That is, it is difficult to ensure a highly reliable connection resistance between the external lead wiring electrode of the liquid crystal display element and the flexible wiring electrode terminal for a predetermined device.

In particular, when the external lead-out wiring electrodes of the liquid crystal display element have a pitch of about 150 to 400 μm, the external lead-out wiring electrodes of the liquid crystal display element are free from cracks and are formed on the same substrate. In order to prevent short-circuit between adjacent electrode patterns and to ensure a highly reliable connection resistance between the wiring electrode for external extraction of the liquid crystal display element and the flexible wiring electrode terminal for a predetermined device, it is necessary to use anisotropic conductive It is desirable that the particle diameter of the conductive particles 1 used for the adhesive 11 be about 20 μm, and the dispersion density at this time is about 320 to 600 particles / mm ² .

More specifically, the above dispersion densities of 320 to 6
In the case of about 00 particles / mm ² , considering the dispersibility of the conductive particles 1, the upper limit value (600 particles / mm ² ) for preventing the occurrence of short circuit between adjacent patterns and the lower limit value (320) for securing the connection resistance reliability are considered. Pieces / mm ² ). In fact, the inventor of the present application has found that the upper limit value of the dispersion density of the conductive particles 1 contained in the anisotropic conductive adhesive 11 when the external lead wiring electrodes of the liquid crystal display element have a pitch of 200 μm. The lower limit was evaluated. As a result, the target value of the probability of occurrence of short-circuit failure between adjacent electrode patterns on the same substrate is set to 10 ⁻⁹ (display capacity VGA (Video Graphics
Assuming that the defective rate with respect to Array) was 1 ppm), the upper limit value of the dispersion density of the conductive particles 1 could be predicted to be about 600 particles / mm ² . On the other hand, in order to ensure the connection resistance reliability between the external lead wiring electrode of the liquid crystal display element and the flexible wiring electrode terminal for a predetermined device, five or more conductive particles are required per electrode terminal. I found it.
Assuming that the target value of the failure probability that the number of conductive particles on one electrode terminal is less than 5 is 10 ⁻⁹ , the lower limit value of the dispersion density could be predicted to be about 320 particles / mm ² . Thus, by setting the dispersion density of the conductive particles 1 in the range of about 320 to 600 particles / mm ² , the connection portion between the external lead-out wiring electrode of the liquid crystal display element and the flexible wiring electrode terminal for the predetermined device is formed. High reliability can be ensured.

Furthermore, in the present invention, the anisotropic conductive adhesive 11 conductive particles 1 contained in the can, characterized compressive deformation characteristics as indicated by C ₁ in FIG. 3 when applying a compressive load thereto It is good to have. Incidentally, in FIG. 3, the compressive deformation characteristics C ₂ or C ₃ of a conventional conductive particle is also shown. The compression deformation characteristics shown in FIG.
(For example, at room temperature 23 ° C.), the amount of compressive deformation S (mm) (or the compressive deformation rate)
(%)).

FIG. 4A shows a state of the conductive particles before the compression weight F is applied, and FIG. 4B shows a state of the conductive particles when the compression weight F is applied. Figure 4
From (a) and (b), the amount of compressive deformation S (mm) and the rate of compressive deformation (%) of the conductive particles are represented by x ₀ which is the particle diameter before applying the compression load F.
Where x is the particle size in the compression direction when the compression load F is applied, the amount of compressive deformation S (mm) = (x ₀ −x), the rate of compressive deformation (%) = (x ₀ −x) / x Is required. Note that FIG.
In this example, as the conductive particles, the particle size x ₀ before adding the compressive load F is used as the order of approximately 20 [mu] m.

Referring to FIG. 3, the conventional conductive particles having a compressive deformation characteristic of C ₂ are elastically deformed when the compressive load (gf / particle) is increased. It has a characteristic with a high rate. That is, it has characteristics as a soft elastic sphere.

Conventional conductive particles having a compressive deformation characteristic of C ₃ are also elastically deformed when the compressive load (gf / particle) is increased. The compression deformation ratio is small.
That is, it has characteristics as a hard elastic sphere.

[0030] In contrast, the conductive particles 1 of the present invention C ₁
When the conductive particles 1 of the present invention have a compressive deformation characteristic of, the conductive particles 1 of the present invention have an initial compressive load F (in the example of FIG. 3, the compressive load F is 2 gf / particle to 3 gf / particle at normal temperature). Although it has elastic properties of hardness almost the same as that of the conventional conductive particles having a compressive deformation property of C ₃ (although it has properties as a hard elastic sphere), a compressive load is 2 gf / particle to 3 g.
When the load value of f / particle is reached (at an early stage), it is crushed and plastically deformed. Here, crushing means that the conductive particles 1 are plastically crushed (plastically deformed) by pressure and do not return to the original shape even when the pressure is released.

[0031] In other words, the conductive particles 1 of the present invention C ₁
When the conductive particles 1 of the present invention are subjected to a compressive load, as shown in FIG.
When the compressive deformation rate of the conductive particles 1 is in the range of 5 to 40%, the conductive particle 1 has an inflection point at which the compressive deformation rate sharply increases.

More specifically, the K value can be used as a value for evaluating the compressive deformation characteristics of the conductive particles (index of hardness evaluation). That is, F is the compression load (kgf), S is the amount of compressive deformation (mm), R is the particle radius (mm), and the compressive elastic deformation characteristics of one conductive particle are expressed by the following equation (Equation 1). If the conductive particles 1 of the compressive deformation characteristics of C ₁
Means that the K value is 10 to 10 when the compressive deformation rate is 40%.
0 (kgf / mm ² ).

[0033]

K = (3/2 ^1/2 ) · (S ^−3/2 ) · (R ^−1/2 ) · F

The above equation (1) is derived as follows. That is, in general, relation between compressive load and deformation amount of the elastic spheres, compression modulus E (kgf / mm ²⁾
When σ is the Poisson's ratio, it can be approximately obtained by the following equation (Equation 2) by applying Schulz's equation.

[0035]

F = (2 ^1/2/3 ) (S ^3/2 ) (R ^1/2 ) (E) / (1−σ ² )

Here, if K = (E) / (1−σ ² ), Equation 1 is derived. Then, in Equation 1, the K value can be obtained from the actually measured values F, S, and R.

In this case, the conductive particles 1 having a compression deformation characteristic of C ₁ have a K value of 10 to 10 when the compression deformation ratio is 40%.
Since the compression deformation rate is 100 (kgf / mm ² ) in the above example, it has characteristics as a hard elastic sphere at the stage of the initial load until the compression deformation rate reaches 40%.

The conductive particles 1 having a compression deformation characteristic of C ₁ have the characteristics of a hard elastic sphere as described above at the initial stage when the compression load is relatively small. When it grows to some extent, it suddenly collapses,
It has the property of plastic deformation. That is, when the particle deformation ratio is in the range of 5 to 40%, there is an inflection point at which the compression deformation ratio sharply increases.

As described above, in the conductive particles 1 of the present invention, the core particles 2 are formed of a predetermined resin material, and the conductive layer 3 is formed on the entire surface of the core particles 2 by a predetermined metal material. The conductive particles 1 are crushed and plastically deformed at a compressive load of 2 gf / particle to 3 gf / particle and have an inflection point at which the compressive deformation rate sharply increases. It is good to be what you are doing.

That is, the conductive particles 1 having the above-mentioned compressive deformation characteristics are particles that are surely crushed when heat-pressing between electrodes or the like using the anisotropic conductive adhesive 11. More specifically, core material particles 2 forming conductive particles 1 of the present invention
Is 10 to 30 kg / cm ² at a temperature of 120 to 170 ° C.
The pressure is preferably crushed by applying pressure for 1 to 10 seconds, and the form is preferably such that the form does not return to the original state even when the pressure is released.

The compressive deformation characteristics C of such conductive particles 1
₁ can give the core material particles 2 of the conductive particles 1. In this case, the core particles 2 having a compressive deformation characteristics C ₁ as described above can be formed of an inorganic material or an organic material. At this time, the core material particles 2 may be solid particles or hollow particles, and furthermore, １ ／ to 1/1 of the average particle size of the core material particles to be used.
An aggregate of fine particles having a particle diameter of about 00 may be used.

More specifically, when the core material particles are formed using an inorganic material, hollow glass particles, hollow silica particles, hollow shirasu particles, hollow ceramic particles, aggregated silica particles, and the like can be used.

As described above, the above-mentioned inorganic material can be used as the core material particles 2. However, since the inorganic material is relatively hard, a resin (polymer) is used as the core material particles 2 in the present invention. ) It is preferable to use particles (for example, particles made of a plastic material).

Among the core particles 2 forming the conductive particles 1, core particles made of resin particles include, for example, (meth) acrylate resin, polystyrene resin, styrene- (meth)
It can be formed of an acrylic copolymer resin, a urethane resin, an epoxy resin, a polyester resin, or the like.

For example, when the core particles are formed of a (meth) acrylate resin, the (meth) acrylic resin is
It is preferably a copolymer of a (meth) acrylic acid ester, a compound having a reactive double bond copolymerizable therewith, if necessary, and a bifunctional or polyfunctional monomer.

When the core material particles are formed of a polystyrene resin, the polystyrene resin may contain a styrene derivative, and if necessary, a compound having a reactive double bond copolymerizable therewith, and a bifunctional compound. Alternatively, it is preferably a copolymer with a polyfunctional monomer.

However, a conventional (meth) acrylate-based resin or polystyrene-based resin has a high compressive breaking strength at a high crosslinking density, and does not cause the conductive particles to be crushed by the pressure at the time of thermocompression bonding. In the case of crosslinking or low crosslinking density, the compression load is 2 gf / particle to 3 gf
Since the conductive particles are crushed at a load value lower than that of the particles and good performance cannot be obtained, a crosslinked structure is formed at an appropriate density in such a resin so that the compressive fracture strength is within the above-mentioned range.
(The conductive particles are crushed when the compression load reaches a load value in the range of 2 gf / particle to 3 gf / particle).

When the core particles have core particles made of a (meth) acrylic resin, the (meth) acrylic resin is preferably a (co) polymer of (meth) acrylic acid ester. A copolymer of this (meth) acrylic ester-based monomer and another monomer can also be used.

Here, examples of the (meth) acrylate-based monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate,
Butyl (meth) acrylate, 2-ethylhexyl (meth)
Acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-propyl (meth) acrylate, chloro-2-hydroxyethyl (meth) acrylate, diethylene glycol mono Examples include (meth) acrylate, methoxyethyl (meth) acrylate, glycidyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and isoboronor (meth) acrylate.

When the core particles forming the conductive particles are a polystyrene resin, specific examples of the styrene monomer include styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, Alkylstyrenes such as triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, hebutylstyrene and octylstyrene; halogenated styrenes such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, iodostyrene and chloromethylstyrene; Styrene, acetylstyrene and methoxystyrene can be mentioned.

The core material particles are preferably formed of one of the above-mentioned (meth) acrylic resin and styrene resin alone, but are formed of a composition comprising these resins. Is also good. Further, a copolymer with the above-mentioned (meth) acrylic ester-based monomer and styrene-based monomer may be used.

Further, the (meth) acrylic resin or styrene resin may include, as necessary, another monomer copolymerizable with the (meth) acrylic ester monomer and / or the styrene monomer. And may be copolymerized.

Examples of other monomers copolymerizable with the (meth) acrylic ester-based monomer or the styrene-based monomer described above include vinyl monomers and unsaturated carboxylic acid monomers.

Here, specific examples of the vinyl monomer include vinyl pyridine, vinyl pyrrolidone, vinyl carbazole, vinyl acetate and acrylonitrile;
Conjugated diene monomers such as butadiene, isoprene and chloroprene; vinyl halides such as vinyl chloride and vinyl bromide; and vinyldene halides such as vinylidene chloride.

Specific examples of the unsaturated carboxylic acid monomer include (meth) acrylic acid, α-ethyl (meth) acrylic acid, crotonic acid, α-methyl crotonic acid, α-ethyl crotonic acid, and isocrotonic acid. , Addition-polymerizable unsaturated aliphatic monocarboxylic acids such as tiglic acid and ungeric acid; addition-polymerizable unsaturated fatty dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, glitaconic acid and hydromuconic acid. Can be mentioned.

In order to form a crosslinked structure in such resin core material particles, a bifunctional or polyfunctional monomer is used. Examples of difunctional or polyfunctional monomers include ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri
(Meth) acrylate, 1,1,1-trishydroxymethylethanediacrylate, 1,1,1-trishydroxymethylethanetriacrylate, 1,1,1-trishydroxymethylpropane triacrylate and divinylbenzene are mentioned. it can.

In particular, it is preferable to use divinylbenzene as the difunctional or polyfunctional monomer. When the core material particles are formed of (meth) acrylic resin,
(Meth) acrylic acid ester monomer
To 100 parts by weight, preferably 40 to 100 parts by weight, a styrene-based monomer, usually 0 to less than 20 parts by weight,
A copolymer obtained by (co) polymerizing a vinyl monomer in an amount of preferably 0 to 15 parts by weight, usually 0 to 50 parts by weight, and an unsaturated carboxylic acid monomer in an amount of usually 0 to 50 parts by weight can be used.

When the core material particles are a styrene resin,
Styrene monomer, usually 20 to 100 parts by weight, preferably 40 to 100 parts by weight, (meth) acrylate monomer, usually 0 parts by weight or more and less than 20 parts by weight,
A copolymer obtained by (co) polymerizing a vinyl monomer in an amount of preferably 0 to 15 parts by weight, usually 0 to 50 parts by weight, and an unsaturated carboxylic acid monomer in an amount of usually 0 to 50 parts by weight can be used.

When the core particles are a copolymer of a (meth) acrylate monomer and a styrene monomer, the (meth) acrylate monomer is usually 20 to 80 parts by weight, preferably 20 to 80 parts by weight. Is 40 to 60 parts by weight, the styrene monomer is usually 20 to 80 parts by weight, preferably 40 to 60 parts by weight, and the vinyl monomer is usually 0 to 5 parts by weight.
0 parts by weight of the unsaturated carboxylic acid monomer,
Copolymers (co) polymerized in parts by weight can be used.

Further, in order to form a crosslinked structure in such resin particles, it is preferable to use a bifunctional or polyfunctional monomer. Then, in order to make the compression breaking strength of the core material particles as in the present invention (the conductive particles are crushed when the compression load reaches a load value in the range of 2 gf / particle to 3 gf / particle). For this purpose, the amount of the bifunctional or polyfunctional monomer is adjusted to form a moderately crosslinked structure. Specifically, in order to achieve the above compressive breaking strength, a bifunctional or polyfunctional monomer is usually used in an amount of 0.1 to 50 parts by weight, preferably 1 to 20 parts by weight.

When the resin particles are prepared by suspension polymerization, by using inorganic particles having a particle size of 1 μm or less, preferably 0.5 μm or less as a protective colloid, spherical resin particles usually have irregularities. Can be given.

The above example is an example of a method for adjusting the compressive breaking strength of a single particle within a predetermined range, and is not limited to a method using such a bifunctional or polyfunctional monomer, but may be another method. Can also be adopted. For example, resin particles having a particle diameter of about 1/3 to 1/100 of the core particles used in the present invention are produced, and these are aggregated to produce aggregated particles having an average particle diameter of about 2 to 30 μm. Such agglomerated particles have their individual particles bonded together with a relatively weak engaging force such as an adsorbing force, and the internal compression breaking strength of such agglomerated particles is 4 kgf / mm ² or less, preferably 3 kgf / mm ² or less.
Particles up to mm ² can be used.

The compression breaking strength of the hollow resin particles can be reduced by, for example, reducing the thickness of the resin, and the compression breaking strength of the hollow resin particles is reduced by, for example, 4 kgf / kg by reducing the thickness of the resin. Hollow resin particles adjusted to not more than mm ² , preferably not more than 3 kgf / mm ² can be used. Furthermore, in the case of such hollow resin particles, instead of adjusting the thickness of the resin, or while adjusting the thickness of the resin, the bifunctional or polyfunctional monomer is copolymerized as described above, so that the compression fracture is caused. The strength can also be adjusted.

As described above, when a compressive load is applied to the core particles 2 of the conductive particles 1, the compressive deformation rate sharply increases when the compressive deformation rate of the conductive particles is in the range of 5 to 40%. One having a compression deformation characteristic having an inflection point, in other words, a compression load of 1 gf / particle to 3 gf /
The particles have the characteristics of hard elastic spheres, but when the compression load reaches 1 gf / particle to 3 gf / particle,
A material having a compression deformation characteristic of crushing and plastically deforming can be used.

When the conductive particles 1 (core material particles 2) further have the above-mentioned compressive deformation characteristics, an anisotropic conductive adhesive containing the conductive particles 1 (anisotropic conductive material) Conductive Film,
Even when the electrodes are electrically conductively bonded using an anisotropic conductive film), it is possible to reliably prevent the electrodes or the substrate from being deformed or damaged.

In the conductive particles 1 used for the anisotropic conductive adhesive 11, the conductive layer 3 is made of a conductive metal, an alloy containing these metals, a conductive ceramic, a conductive metal oxide, or another conductive metal. Of the conductive material.

Examples of the conductive metal include Zn, Al, S
b, U, Cd, Ga, Ca, Au, Ag, Co, Sn,
Se, Fe, Cu, Th, Pb, Ni, Pd, Be and Mg can be mentioned. The above-mentioned metals may be used alone, or two or more kinds may be used, and other elements and compounds (for example, solder) may be added. Examples of conductive ceramics include Vo ₂ , Ru ₂ O, SiC,
ZrO ₂ , Ta ₂ N, ZrN, NbN, VN, TiB ₂ ,
_{ZrB, HfB 2, TaB 2,} MoB 2, CrB 2, B
₄ C, mention may be made of MoB, ZrC, a VC and TiC. In addition, as conductive materials other than the above, carbon particles such as carbon and graphite, and ITO
And the like.

Among such conductive materials, it is particularly preferable that the conductive layer 3 contains gold. Conductive layer 3
By adding gold to the metal, the electric resistance value is reduced, the spreadability is improved, and good conductivity can be obtained. In addition, since gold has low hardness, as described later, an anisotropic conductive adhesive (anisotropic conductive film, anisotropic conductive film) containing the conductive particles 1 is used to perform conductive bonding between the electrodes. In such a case, there is little damage to the electrodes and the like.

In particular, as the conductive layer 3, as shown in FIG. 5, for example, gold (A) is formed on the surface of a nickel (Ni) metal layer 3a.
u) It is preferable to use the one on which the layer 3b is formed (substituted by gold (Au)).

The above-mentioned various conductive layers 3 are formed by a physical method such as a vapor deposition method, an ion sputtering method, an electroless plating method, and a thermal spraying method. Chemical method of bonding to the surface, method of adsorbing conductive material on the surface of the core material using a surfactant, etc., conductive particles coexist in the reaction system when forming the core material, and conductive on the surface of the core material The core material and the conductive layer can be simultaneously formed while precipitating the conductive particles. In particular, it is preferable to form this conductive layer by an electroless plating method, and to promote the oxidation-reduction reaction in the electroless plating step by increasing the concentration of pacidium in the pretreatment step of the electroless plating as compared with the conventional method. Good. Such a conductive layer does not need to be a single layer, and a plurality of layers may be stacked.

The thickness of the conductive layer 3 is usually 0.01 to 10.0 μm, preferably 0.05 to 5 μm.
m, more preferably in the range of 0.2 to 2 μm.
An insulating layer made of an insulating resin may be further formed on the surface of the composite particles. As an example of a method of forming an insulating layer, a method of forming a discontinuous insulating layer made of polyvinylidene fluoride by a hybridization system is described.
85 to 11 parts by weight of polyvinylidene fluoride, 85 to 11 parts by weight
Treat at a temperature of 5 ° C. for 5-10 minutes. The thickness of this insulating layer is usually about 0.1 to 0.5 μm. Note that the insulating layer may incompletely cover the surface of the conductive particles.

As described above, in the conductive particles 1 of the present invention, any conductive material can be used for the conductive layer 3, and the conductive layer 3 can have any layer configuration.

Further, the conductive particles 1 contained in the insulating adhesive 12 of the anisotropic conductive adhesive 11 can be converted into a plurality of conductive members (for example,
When applying a predetermined compressive load to the anisotropic conductive adhesive between conductive members to conductively bond between the two wiring patterns)
It is preferable that the irregularities on the surface of the conductive particles 1 are formed to a degree sufficient to reach the conductive member by removing the insulating adhesive interposed between the conductive particles and the conductive member. .

FIGS. 6A and 6B show examples of the structure of the conductive particles 1 having the above-mentioned unevenness on the surface. First, referring to FIG. 6A, the irregularities 6 on the surface of the conductive particles 1 have a depth in the range of, for example, 0.05 to 2 μm. 100 density
It is in the range of 0 to 500,000 pieces / mm ² .

More specifically, the conductive particles 1 are shown in FIG.
As shown in (b), the surface irregularities 6 are defined by the irregularities of the conductive layer 3.

FIGS. 7A and 7B show the conductive particles 1 of the present invention.
3 is a photograph showing an example of the above. 8 (a) and 8 (b) show conventional conductive particles (conductive particles having almost no irregularities on the surface) for comparison with the conductive particles 1 of FIGS. 7 (a) and 7 (b). A photograph of one example is also shown. 7 (a), 7 (b), 8 (a),
(b) shows conductive particles having a particle diameter of 20 μm in about 4000
Photographed at double magnification.

Here, the conductive particles 1 of the present invention shown in FIGS. 7A and 7B use polystyrene for the core particles 2, and the conductive layer 3 contains the polystyrene core particles 2. The palladium concentration in the pretreatment step of electroless plating is twice the concentration of a conventionally known method, electroless Ni plating is performed, and the surface is further Au-plated.

The conventional conductive particles 1 shown in FIGS. 8 (a) and 8 (b) are obtained by forming the conductive layer 3 by a conventionally known electroless Ni plating.

The conductive particles 1 of the present invention shown in FIGS. 7 (a) and 7 (b) are different from those shown in FIGS.
As compared with the conventional conductive particles of (a) and (b), the surface has irregularities of sufficient depth and surface density.
(b) The conductive particles of the present invention are contained in an insulating adhesive to form an anisotropic conductive adhesive, and a plurality of conductive members (for example, wiring patterns) are formed using the anisotropic conductive adhesive. When a predetermined compressive load is applied to the anisotropic conductive adhesive between the conductive members in order to conductively bond the conductive particles, the unevenness 6 on the surface of the conductive particles 1 causes the insulating material interposed between the conductive particles and the conductive member. The conductive adhesive can be eliminated to reach the conductive member, and therefore, even if the insulating adhesive is present, the conductive particles 1 and the conductive member (for example, a wiring pattern) can be reliably conductive. Connection can be established.

In the anisotropic conductive adhesive 11 of FIG. 1, as the insulating adhesive 12, for example, a (meth) acrylic adhesive, an epoxy adhesive, a polyester adhesive,
Urethane-based adhesives and rubber-based adhesives can be used. In particular, in the present invention, it is preferable to use a (meth) acrylic resin adhesive.

Examples of the acrylic resin adhesive include:
Copolymers of (meth) acrylate and a compound having a reactive double bond copolymerizable therewith can be exemplified. Examples of the (meth) acrylate used here include methyl (meth) acrylate, ethyl (meth)
Acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl
(Meth) acrylate, cyclohexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, chloro-2-hydroxypropyl (meth) acrylate, diethylene glycol mono (meth) acrylate, methoxyethyl ( (Meth) acrylate, ethoxyethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate and glycidyl
(Meth) acrylates can be mentioned.

Examples of the compound having a reactive double bond copolymerizable with the (meth) acrylic acid ester include unsaturated carboxylic acid monomers, styrene monomers and vinyl monomers. .

Here, examples of the unsaturated carboxylic acid monomer include acrylic acid, (meth) acrylic acid, α-ethylacrylic acid, crotonic acid, α-methylcrotonic acid, α-ethylcrotonic acid, isocrotonic acid, tiglin Addition-polymerizable unsaturated aliphatic monocarboxylic acids such as acid and ungeric acid; and addition-polymerizable unsaturated aliphatic dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid and dihydromuconic acid. be able to.

Examples of styrene monomers include:
Alkylstyrenes such as styrene, methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene and octylstyrene; fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene And halogenated styrenes such as iodostyrene;
Nitrostyrene, acetylstyrene and methoxystyrene can be mentioned.

Further, examples of the vinyl monomer include:
Vinyl pyridine, vinyl pyrrolidone, vinyl carpazole, divinyl benzene, vinyl acetate and acrylonitrile; conjugated diene monomers such as butadiene, isoprene and chloroprene; vinyl halides such as vinyl chloride and vinyl bromide; and vinylidene halides such as vinylidene chloride. be able to.

[0086] The (meth) acrylic resin adhesive is
(Meth) acrylic acid ester usually 60 to 90 parts by weight,
It is produced by copolymerizing other monomers usually in an amount of 10 to 40 parts by weight.

Such an acrylic adhesive can be produced by a usual method. For example, it can be produced by dissolving or dispersing the above-mentioned monomer in an organic solvent, and reacting the solution or dispersion in a reactor substituted with an inert gas such as nitrogen gas. Examples of the organic solvent used herein include aromatic hydrocarbons such as toluene and xylene; aliphatic hydrocarbons such as n-hexane; esters such as ethyl acetate and butyl acetate;
Examples include aliphatic alcohols such as propyl alcohol and i-propyl alcohol, and ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone. In the above reaction, the organic solvent is usually used in an amount of 100 to 250 parts by weight based on 100 parts by weight of the (meth) acrylic resin adhesive forming raw material.

This reaction is carried out by heating in the presence of a polymerization initiator. Examples of the reaction initiator used here include azobisisobutyronitrile, benzoyl peroxide, di-tert-butyl peroxide, cumene hydroperoxide and the like. The polymerization initiator is used usually in an amount of 0.01 to 5 parts by weight based on 100 parts by weight of the raw material monomer.

In the polymerization reaction in an organic solvent as described above, the reaction solution is usually heated to 60 to 75 ° C.,
The reaction is performed for 10 hours, preferably for 4 to 8 hours. The weight average molecular weight of the (meth) acrylic resin adhesive thus produced is usually in the range of 100,000 to 1,000,000.

In such an acrylic adhesive, a thermoplastic resin such as an alkylphenol, terpene phenol, modified rosin, or xylene resin may be blended, or a reactive curable resin such as an epoxy resin may be blended. Further, a curing agent such as an imidazole compound of such a reaction curable resin can be blended.

Further, the insulating adhesive 12 used in the present invention preferably contains a filler. Here, as the filler, insulating inorganic particles are preferable. Examples of the filler include titanium oxide, silicon dioxide, calcium carbonate,
Mention may be made of calcium phosphate, aluminum oxide and antimony oxide. These insulating inorganic particles usually have an average particle size of 0.01 to 5 μm. These insulating inorganic particles can be used alone or in combination.

The insulating inorganic particles are usually 10 to 100 parts by weight based on 100 parts by weight of the resin component in the adhesive.
It is preferably used in an amount of 50 to 80 parts by weight.

By mixing the insulating inorganic particles in the above-described amount as a filler, the fluidity of the adhesive 12 can be adjusted, and even if heated after bonding, the adhesive 12 flows backward to inhibit conductivity. Less to do. Further, for example, when the two substrates face each other and the conductive patterns are electrically bonded between the wiring patterns on each substrate, it is possible to prevent the adhesive 12 from protruding from the ends of the substrates. By using the silicon resin powder and / or silicon dioxide in this way,
The bonding reliability and conduction reliability with respect to the stress resistance of the anisotropic conductive adhesive 11 of the present invention are improved.

As described above, the anisotropic conductive adhesive 1 of the present invention
1 (anisotropic conductive film, anisotropic conductive film) can be produced by mixing the above components.

Further, the anisotropic conductive adhesive 11 of the present invention
When this is configured as an anisotropic conductive film (film), the film
The thickness of the (sheet) is preferably in the range of 10 to 50 μm. In order to form the anisotropic conductive adhesive 11 of the present invention into a sheet, for example, a knife coater, a comma coater, a reverse roll coater, a gravure coater or the like can be used.

The sheet-shaped anisotropic conductive adhesive 11 of the present invention (that is, an anisotropic conductive film) can be used, for example, as shown in FIG. That is, FIG.
(a) and (b) schematically show examples of bonding a substrate using the anisotropic conductive film of the present invention.

In the example of FIGS. 9A and 9B, first, FIG.
As shown in the figure, a wiring pattern (conductive member) 19 is formed on the surface.
a and 19b are formed on the two substrates 18a and 18b,
The wiring patterns 19a and 19b are arranged so as to face each other, and the sheet-shaped anisotropic conductive adhesive 11 (anisotropic conductive film) of the present invention is sandwiched between the wiring patterns 19a and 19b. Note that this anisotropic conductive film 11
For example, the conductive particles 1 of the present invention are dispersed in an insulating adhesive 12 made of an acrylic adhesive, and a filler 16 is further dispersed.

The substrates 18a and 18b on which the anisotropic conductive film 11 is disposed are, for example, 30 to 100 kg at a temperature of 120 ° C. to 170 ° C. in the direction of the arrow shown in FIG.
When / cm to pressurizing the adhesive in the ^second pressure, as shown in FIG. 9 (b), it receives the wiring patterns 19a, 19b having the highest pressure the conductive particles 1 in between. At this time, even if the insulating adhesive 12 remains between the conductive particles 1 and the wiring patterns 19a and 19b, the irregularities on the surface of the conductive particles 1 may cause the conductive particles 1 to become uneven between the conductive particles and the conductive member. The wiring pattern 19a, 19b is reliably reached by removing the insulating adhesive interposed therebetween, whereby the conductive particles 1 and the wiring pattern 19 are removed.
a, 19b. At this time, when the conductive particles 1 between the wiring patterns 19a and 19b receive the highest pressure, the conductive particles 1 are crushed. The state where the conductive particles 1 are crushed is shown in more detail in FIG. In FIG. 10, 1b is a non-crushed conductive particle, and 1a is a crushed conductive particle.

The pressure applied to the substrate during the thermocompression bonding is as follows:
Generally, the pressure is 30 to 100 kg / cm ² , but the conductive particles 1 are crushed by applying a pressure of, for example, 10 to 30 kg / cm ² . Then, in the portion where the wiring pattern is formed,
Wiring patterns 19a and 19 are formed by conductive particles 1a crushed by wiring patterns 19a and 19b.
b is conducted. On the other hand, since such pressure is not applied to the particles 1b in the portion where the wiring pattern is not formed, a good insulating property is exhibited. Thus, anisotropic conductive bonding can be performed.

In the above description, the embodiment in which the anisotropic conductive adhesive 11 of the present invention is used in the form of a sheet (in the form of an anisotropic conductive film) is used. Can be used in a paste form by containing an appropriate solvent. This paste-shaped anisotropic conductive adhesive 11 can be used as an anisotropic anisotropic conductive adhesive in the same manner as described above, for example, by applying it on a substrate using a screen coater or the like. That is, the anisotropic conductive adhesive 11 of the present invention can be used in various forms such as a paste shape as well as a sheet shape (film shape).

By the way, the anisotropic conductive adhesive 11 of the present invention
The conductive particles 1 having a particle size of about 20 μm are dispersed in the insulating adhesive at a dispersion density of 300 particles / mm ^{2 to} 650 particles / mm ² , more preferably 320 particles / mm ^{2 to} 600 particles / m ^2.
Since the liquid crystal display element is dispersed with a dispersion density of m ² , even when the external lead wiring electrodes of the liquid crystal display element have a pitch of about 150 to 250 μm (even at a fine pitch), A crack is not generated in the external lead-out wiring electrode, and a short circuit between adjacent electrode patterns on the same substrate is prevented, and between the external lead-out wiring electrode of the liquid crystal display element and the flexible wiring electrode terminal for a predetermined device. A highly reliable connection resistance can be secured.

Specifically, in recent years, PDAs (Personal Digital Assistants),
2. Description of the Related Art As a display serving as a man-machine interface in a portable device such as a mobile phone, a liquid crystal display device using a polymer film having a thin, lightweight, non-breakable characteristic as a substrate has attracted attention. FIG. 11 is a schematic plan view showing an example of this type of liquid crystal display device (liquid crystal display device), and FIG. 12 is a sectional view taken along line AA in FIG.

Referring to FIGS. 11 and 12, a stripe-shaped ITO electrode (wiring pattern) 2 formed at a predetermined interval is formed on the surface of the first polymer film substrate 21.
2 and an alignment film 23 are formed. On the back surface of the first polymer film substrate 21, a polarizing plate 24, a reflecting plate 25
Are sequentially formed. On the surface of the second polymer film substrate 31 are formed stripe-shaped ITO electrodes (wiring patterns) 32 formed at regular intervals and an alignment film 33.
A polarizing plate 34 is formed on the back surface of the.

Here, the first polymer film substrate 2
The first polymer film substrate 31 is made of, for example, polycarbonate (PC), polyether sulfone (PE).
S) or a material such as polysulfone (PS) with a thickness of, for example, 0.1 to 0.2 mm.

Further, a sealing material 26 is provided on the surface of the first polymer film substrate 21, and a predetermined distance is provided on the surface of the second polymer film substrate 31 (on the surface of the alignment film 33). , A gap material (spacer) 35 is disposed.

Here, the first polymer film substrate 21 and the ITO film formed on the substrate 21 are formed.
The electrode 22, the alignment film 23, the sealing material 26, the polarizing plate 24, and the reflecting plate 25 are collectively referred to as a lower substrate 20, and a second polymer film substrate 31,
The ITO electrode 32, the alignment film 33, the gap material 35, and the polarizing plate 34 formed on the substrate are collectively referred to as an upper substrate 30.

In the examples shown in FIGS. 11 and 12, the lower substrate 20 and the upper substrate 30 are connected in such a manner that the wiring pattern of the ITO electrode 22 and the wiring pattern of the ITO electrode 32 are orthogonal to each other. Part of electrode 22, ITO
Face-to-face (facing) so that a part of the electrode 32 is exposed
Then, they are heat-pressed to form a substrate for a liquid crystal display element. That is, the lower substrate 20 and the upper substrate 30 face each other at an interval determined by the thickness of the gap material (spacer) 35, and the lower substrate 20 and the upper substrate 30
The lower substrate 20 and the upper substrate 30 are exposed in such a manner that a part of the ITO electrode 22 and a part of the ITO electrode 32 are exposed.
Of the sealing material 2 except for the liquid crystal injection part 40.
6 to form a substrate for a liquid crystal display element.

In such a liquid crystal display substrate, a liquid crystal material is injected from a liquid crystal injection portion 40 into a gap separated by a gap material 35 between the lower substrate 20 and the upper substrate 30, and thereafter, the liquid crystal injection is performed. By sealing the portion 40 with a sealing agent, this can be manufactured as a liquid crystal display element.

In the liquid crystal display device thus manufactured,
Striped ITO electrode 22 and striped ITO
The intersection with the electrode 23 (intersection of the wiring pattern) can function as one dot on the liquid crystal display screen. That is, by applying a predetermined drive signal to each of the exposed portions of the ITO electrode 22 and the ITO electrode 32,
By changing the alignment state of the liquid crystal at the intersection of the TO electrode 22 and the ITO electrode 32, predetermined characters and figures can be displayed on this screen when viewed from the upper substrate 30 side.

In other words, in the configuration examples shown in FIGS. 11 and 12, the portion of the ITO electrode 22 exposed on the lower substrate 20 and the portion of the ITO electrode 32 exposed on the upper substrate 30 are formed.
Function as an external lead-out wiring electrode (lower electrode lead-out part) 42 and an external lead-out wiring electrode (upper electrode lead-out part) 43, respectively. The display can be performed by providing the driving signals. For this reason,
The external lead-out wiring electrode (lower electrode lead-out part) 42 and the external lead-out wiring electrode (upper electrode lead-out part) 43
Usually, flexible wiring electrode terminals for drive circuit devices are connected by thermocompression bonding. That is, the electrode terminals on the drive circuit board are connected by thermocompression bonding.

In the configuration examples shown in FIGS. 11 and 12, the so-called double-sided electrode extraction is provided in which the external lead-out wiring electrodes (electrode extraction portions) 42 and 43 are provided on the lower substrate 20 and the upper substrate 30, respectively. Although it is of a model type, it is also possible to adopt a configuration in which both the external lead-out wiring electrodes (electrode take-out portions) 42 and 43 are provided only on either the lower substrate 20 or the upper substrate 30 ( That is, a so-called one-sided electrode extraction type may be used.

FIG. 13 is a schematic plan view showing an example of a liquid crystal display element (liquid crystal display device) of a one-sided electrode extraction type, and FIG. 14 is a sectional view taken along line BB of FIG. In the case of the one-side electrode extraction type as shown in FIG. 13, for example, the wiring pattern of the striped ITO electrode 22 on the lower substrate 20 is changed to the striped ITO electrode on the upper substrate 30 immediately before the sealing material 26, for example. It is bent at a right angle so as to be parallel to the wiring pattern of the electrode 32, and the IT
This wiring pattern of the O electrode 22 is extended on the upper substrate 30 via upper and lower conductive portions (through holes) 29 formed in the sealing material 26 (see FIG. 14), and the ITO The wiring is exposed together with the wiring pattern of the electrode 32 to form a wiring electrode (electrode extraction portion) 42 for external drawing.
Can be configured as That is, the upper substrate 30
On the top, a wiring electrode for external extraction (electrode extraction portion) 42,
43 can be provided.

By the way, even in the case of the both-side electrode take-out type as shown in FIGS.
As described above, even the one-sided electrode take-out type electrodes such as 4, the external lead-out wiring electrodes (electrode take-out portions) 42, 43 are usually provided with flexible wiring electrode terminals for drive circuit devices (that is, The electrode terminals on the drive circuit board are connected by thermocompression bonding. To perform this thermocompression connection, the anisotropic conductive adhesive of the present invention described above (anisotropic conductive film)
11 can be used.

FIGS. 15 and 16 show a thermocompression connection between a wiring electrode (conductive member) for external drawing of a liquid crystal display element substrate and a flexible wiring electrode terminal (conductive member) for a drive circuit device according to the present invention. Anisotropic conductive adhesive (anisotropic conductive film) 11
FIG. 4 is a diagram showing an example of a method performed using the method. FIG.
5 (a), (b) and (c) are side views, and FIGS. 16 (a) and (b)
16 is a plan view corresponding to FIGS. 15A and 15B. FIG. In FIGS. 15 and 16, in the liquid crystal display device of the double-sided electrode extraction type as shown in FIGS. 11 and 12, the external lead-out wiring electrode 22 (lower electrode extraction portion 42) on the lower substrate 20 is used.
2 shows a case where the electrode terminals 52 on the drive circuit board 51 are connected by thermocompression bonding. Further, in this case, the anisotropic conductive adhesive (anisotropic conductive film) 11 is generally provided as a reel-shaped product, and the reel-shaped anisotropic conductive adhesive (anisotropic conductive film) 11 is sequentially provided. It is designed to be unrolled and used. In the example of FIG. 15, the separator 60 is attached to the anisotropic conductive adhesive (anisotropic conductive film) 11 in advance.

Referring to FIGS. 15 and 16, first, the anisotropic conductive adhesive (anisotropic conductive material) of the present invention is placed on the external lead-out wiring electrode (lower electrode lead-out portion) 42 on the lower substrate 20. Film 11), and an anisotropic conductive adhesive (anisotropic conductive film) 11 is placed on the lower substrate 20 at a temperature of 60 ° C. to 80 ° C., for example. ) 42 (FIGS. 15A and 16A). At this time,
The separator 60 is made of an anisotropic conductive adhesive (anisotropic conductive film) 1
Peeled from 1.

Thereafter, the drive circuit board is placed on the external lead-out wiring electrode (lower electrode extraction portion) 42 on the lower substrate 20 via the anisotropic conductive adhesive (anisotropic conductive film) 11. Positioning the electrode terminal 52 on 51 (FIG. 15 (b),
FIG. 16 (b)). After such positioning, the anisotropic conductive adhesive (anisotropic conductive film) 11 is attached to the lower substrate 20.
The drive circuit board 51 is thermocompression-bonded through
(c)). In addition, this thermocompression bonding process can be performed in two stages of a temporary process and a main process.
Temperature of 110 ° C to 150 ° C (preferably about 130 ° C);
It can be performed at a pressure of 4 MPa (preferably about 3 MPa) for about 5 to 15 seconds (preferably about 10 seconds).

By such thermocompression bonding, the anisotropic conductive adhesive (anisotropic conductive film) 11 between the lower substrate 20 and the drive circuit board 51 is shown in FIGS. 9B and 10. It will be in the same state as above. That is, the external lead-out wiring electrode 42 on the lower substrate 20 and the electrode terminal 52 on the drive circuit substrate 51
Is present in the lower substrate 20 by the conductive particles 1a crushed by the external lead-out wiring electrodes 42 on the lower substrate 20 and the electrode terminals 52 on the drive circuit substrate 51.
The upper external lead-out wiring electrode 42 and the electrode terminal 52 on the drive circuit board 51 conduct. On the other hand, such pressure is not applied to the particles 1b in the portion where the external lead-out wiring electrode 42 on the lower substrate 20 and the electrode terminal 52 on the drive circuit substrate 51 do not exist, so that good insulation is exhibited. Thus, anisotropic conductive bonding can be performed.

In the present invention, the anisotropic conductive adhesive 11 has an average particle diameter of the conductive particles 1 in the range of 2 μm to 30 μm, and the conductive particles are contained in the insulating adhesive. Are dispersed at a dispersion density of 300 pieces / mm ^{2 to} 650 pieces / mm ² , so that the external lead-out wiring electrodes 22 of the lower substrate 20 have a pitch of about 150 to 250 μm.
(Shown by the reference symbol P in FIG. 16A),
A crack is not generated in the external lead-out wiring electrode 22 of the lower substrate 20 and a short circuit between adjacent electrode patterns on the same substrate is prevented. A highly reliable connection resistance between the flexible wiring electrode terminal 52 and the flexible wiring electrode terminal 52 can be secured.

In particular, when the pitch P of the external lead-out wiring electrodes 22 of the lower substrate 20 is about 200 μm, the conductive particles 1 used for the anisotropic conductive adhesive 11 have a particle diameter of about 20 μm. Preferably, the dispersion density of the conductive particles 1 is 320 to 600 particles / mm ² .

Further, the anisotropic conductive adhesive (anisotropic conductive film) 11 of the present invention is used, for example, by connecting the external lead-out wiring electrode 22 (lower electrode extraction portion 42) on the lower substrate 20 to the drive circuit device. When used for anisotropic conductive bonding with the flexible wiring electrode terminals (that is, the electrode terminals 52 on the drive circuit board 51), the anisotropic conductive adhesive (anisotropic conductive film) 11 of the present invention is shown in FIG. As shown, the relationship between the particle diameter D of the conductive particles 1 and the film thickness T of the insulating adhesive (binder) 12 is D
It may be configured so that ≧ T.

More specifically, the insulating adhesive (binder) 1
The thickness T of the electrode terminals 5 on the lower circuit board 20 and the electrode terminals 5 on the drive circuit board 51 at the time of thermocompression bonding.
2 is almost completely filled with the anisotropic conductive adhesive (anisotropic conductive film) 11 of the present invention, and the excess adhesive
It is preferable that the (binder) 12 does not overflow from between the lower substrate 20 and the drive circuit substrate 51.

As described above, the relationship between the particle diameter D of the conductive particles 1 and the film thickness T of the insulating adhesive (binder) 12 is such that D ≧ T. (Binder) 1 between the conductive particles 1 and the electrodes 22 and 52
2 can be further reduced, and the anisotropic conductive bonding between the lower substrate 20 and the electrode terminals 52 on the drive circuit substrate 51 can be more reliably performed. Furthermore, in this case,
At the time of thermocompression bonding, excess adhesive (binder) 12 can be prevented from overflowing the substrate.

Specifically, if the thickness T of the anisotropic conductive adhesive 11, particularly the insulating adhesive 12, is too small, the external lead-out wiring electrode 22 on the lower substrate 20 and the drive circuit The connection reliability between the electrode terminal 52 and the electrode terminal 52 is reduced due to the generation of air bubbles.
If the thickness T of the conductive particles 1 is too large, the removability of the insulating adhesive (binder) 12 between the conductive particles 1 and the electrodes decreases, and the contact area decreases due to insufficient compressive deformation of the conductive particles 1. (That is, it is difficult to reliably make the conductive particles 1 and the electrodes conductively contact.) Therefore, the film thickness T of the insulating adhesive 12 needs to be set to an appropriate value.

The inventor of the present application has found that when a low-resistance polymer film substrate and a high-resistance polymer film substrate are used as substrates for a liquid crystal display element, respectively, the electrode film having a thickness of 22 μm is formed on the electrodes on these substrates. The applicable range of the film thickness T of the conductive adhesive 12 when connecting the flexible electrode terminals was evaluated. As a result, it was found that the connection reliability could be ensured over a wide range of film thicknesses T for a low-resistance polymer film substrate. On the other hand, for a high-resistance polymer film substrate, the particle diameter D of the conductive particles 1
When the film thickness T of the conductive adhesive 12 is larger than that, the connection resistance increases from the beginning, and the tendency becomes remarkable by an environmental test. This is presumably because the connection area between the conductive particles 1 and the electrode needs to be increased in connection with the electrode of the high-resistance polymer film substrate. However, the variation in the film thickness of the reel-shaped anisotropic conductive adhesive 11 in the manufacturing process of forming the anisotropic conductive adhesive 11 into a reel is ±
2 μm, the anisotropic conductive adhesive 11 during mass production
Even when the film thickness varies, the connection reliability to the high-resistance polymer film substrate can be ensured.

As described above, in connection with a low-resistance polymer film substrate, connection reliability can be obtained even when the amount of deformation of the conductive particles is small, and even when the thickness of the flexible electrode terminal is 35 μm, the difference is small. One side conductive adhesive 11
By properly setting the film thickness, good connection reliability was obtained. On the other hand, in connection with a high-resistance polymer film substrate, it is necessary to set the film thickness T of the conductive adhesive 12 smaller than the particle diameter D of the conductive particles 1 so that the contact area of the conductive particles 1 can be increased. The standard electrode thickness of the flexible electrode terminal is preferably 18 μm.

Specifically, when the electrode terminal 52 on the drive circuit board 51 has an electrode film thickness of, for example, 18 μm, the film thickness T of the insulating adhesive (binder) 12 is about 16 ± 3 μm. In this case, the particle diameter D of the conductive particles 1 is used.
Is preferably about 20 μm.

In other words, from the viewpoint that the relationship between the particle diameter D of the conductive particles 1 and the film thickness T of the insulating adhesive (binder) 12 is such that D ≧ T, the anisotropic conductive adhesive 1
It is preferable that the particle diameter of the conductive particles 1 used in the first step is about 20 μm.

Further, the anisotropic conductive adhesive 11 of the present invention
Is, as described above, the conductive particles 1 contained therein,
At the initial stage where the compressive load is relatively small, it has the characteristics as a hard elastic sphere as described above, and when the compressive load increases to some extent, it suddenly collapses, Crush with a pressure lower than the pressure applied during the pressure bonding operation. Therefore, when anisotropic conductive bonding is performed on the electrode formed on the film liquid crystal and the electrode formed on the flexible printed board using the anisotropic conductive adhesive (anisotropic conductive adhesive) 11. Therefore, these electrodes and the substrate are not deformed or damaged.

FIGS. 18 (a), (b) and (c) show the external parts on the lower substrate 20 using the conductive particles having the compression deformation characteristics C ₁ , C ₂ and C ₃ of FIG. Leading wiring electrode 42
The schematic diagram shows the case where conductive bonding is performed between the electrode terminal 52 on the drive circuit board 51 and the electrode terminal 52 on the drive circuit board 51. Note that FIG.
In the examples of (a), (b) and (c), as shown in FIGS. 8 (a) and 8 (b), the case where conductive particles having less unevenness on the surface are used is shown.

As described above, the conventional conductive particles having a compressive deformation characteristic of C ₂ have a large amount of compressive deformation and a large compressive deformation ratio with respect to a compressive load (that is, as a soft elastic sphere). Properties),
As shown in FIG. 18B, the external lead-out wiring electrode 42 on the lower substrate 20 and the electrode terminal 52 on the drive circuit substrate 51
When thermocompression bonding is performed between the conductive particles 1 and the conductive particles 1, the conductive particles are easily deformed, and the wiring electrodes 42 for external extraction on the lower substrate 20, the electrode terminals 52 on the drive circuit board 51, and the conductive particles 1 In between, the insulating adhesive (binder) 12 is left (the conductive particles 1 are connected to the external lead-out wiring electrode 42 on the lower substrate 20 and the electrode terminal 52 on the drive circuit board 51).
), And good conductive adhesion cannot be achieved.

Further, as described above, the conventional conductive particles having a compressive deformation characteristic of C _{3 have} an amount of compressive deformation with respect to a compressive load,
Although the compressive deformation rate has a small characteristic (that is, it has the characteristics of a hard elastic sphere), since the characteristics of this hard elastic sphere are maintained within a range where the compressive load is considerably large, As shown in FIG. 18C, the external lead-out wiring electrode 42 on the lower substrate 20 and the drive circuit substrate 5
When the thermocompression bonding is performed between the electrode terminal 52 and the upper electrode 1, the hard conductive particles 1 do not crush and deform or damage the substrate 20 and the electrodes 42 and 52 until the compression load becomes considerably large. (For example, cracks may occur in the ITO electrode).

On the other hand, as shown in FIG. 18A, the conductive particles 1 having the compression deformation characteristic of C ₁ are connected to the external lead-out wiring electrode (lower electrode extraction portion) 42 on the lower substrate 20. When performing thermocompression bonding with a flexible wiring electrode terminal for a drive circuit device (that is, the electrode terminal 52 on the drive circuit board 51), the rate at which the conductive particles 1 directly contact the electrode due to the initial hardness. At this stage, the conductive particles 1 are crushed and the substrate 2
0 and the electrodes 42 and 52 are not deformed or damaged, and the crushing causes the contact area between the conductive particles 1 and the electrodes 42 and 52 without deforming or damaging the substrate 20 and the electrodes 42 and 52. Can be increased.

As described above, by using the conductive particles 1 having a compressive deformation characteristic of C ₁ and the anisotropic conductive adhesive (anisotropic conductive film) 11 using the conductive particles, external drawing on the lower substrate 20 can be performed. Conductive bonding between the wiring electrodes 42 for use and the electrode terminals 52 on the drive circuit board 51 can be performed more reliably.

Further, the anisotropic conductive adhesive 11 of the present invention
Since irregularities of sufficient depth and surface density are formed on the surface of the conductive particles 1 contained therein, conductive bonding between a plurality of conductive members is performed using the anisotropic conductive adhesive material 11. When applying a predetermined compressive load to the anisotropic conductive adhesive between the conductive members, irregularities on the surface of the conductive particles eliminate the insulating adhesive interposed between the conductive particles and the conductive member. As a result, the conductive member reaches the conductive member, whereby the conductive connection between the conductive particles 1 and the conductive member can be more reliably achieved.

In each of the above-described examples, the liquid crystal display element of the both-side electrode take-out type as shown in FIGS.
A case where the external lead-out wiring electrode (lower electrode take-out portion) 42 on the lower substrate 20 and the flexible wiring electrode terminal for the drive circuit device (that is, the electrode terminal 52 on the drive circuit substrate 51) are connected by thermocompression bonding. As described above, in the liquid crystal display element of the double-sided electrode extraction type as shown in FIGS. 11 and 12, a flexible wiring electrode for a drive circuit device is provided on the external lead-out wiring electrode (lower electrode extraction portion) 43 on the upper substrate 30. When the terminals (that is, the electrode terminals on the drive circuit board) are connected by thermocompression bonding, the connection can be performed in exactly the same manner as described above.
3, in a liquid crystal display element of a one-sided electrode extraction type as shown in FIG. 14, for example, flexible wiring electrode terminals (for a drive circuit device) are connected to external extraction wiring electrodes (lower electrode extraction portions) 42 and 43 on the upper substrate 30. That is, the case where the electrode terminals on the drive circuit board are connected by thermocompression bonding can be performed in exactly the same manner as described above.

However, in the present invention, in the anisotropic conductive bonding between the external lead-out wiring electrode 42 on the lower substrate 20 and the electrode terminal 52 on the drive circuit board 51, the pitch between the electrode patterns is about 200 μm. In order to perform this with high reliability even in the case of fine particles, the minimum condition is that the conductive particles are contained in the insulating adhesive at a rate of 300 particles / particle.
mm ^{2 to} 650 particles / mm ² , and the average particle diameter of the conductive particles dispersed in the insulating adhesive is in the range of 2 μm to 30 μm. It is sufficient if the conductive adhesive 11 is provided, and the conductive particles 1 are further provided with the compression deformation characteristic of C ₁ , or the external lead-out wiring electrode 42 on the lower substrate 20 and the driving circuit When a predetermined compressive load is applied to the anisotropic conductive adhesive 11 between the electrode terminals 52 on the substrate 51, the irregularities on the surface of the conductive particles 1 break through the coating of the insulating adhesive 12 and Being formed to a degree sufficient to reach 52 is an incidental condition only.

[0137]

As described above, according to the anisotropic conductive adhesive of the present invention, the conductive particles are dispersed in the insulating adhesive at a ratio of 300 particles / mm ^{2 to} 650 particles / mm ² . Even if the pitch of the external lead-out wiring electrodes of the liquid crystal display element is as fine as, for example, about 200 μm, the wiring leads may damage the external lead-out wiring electrodes of the liquid crystal display element such as cracks. In addition, conductive bonding can be performed with high reliability such that short-circuiting (conductive contact) does not occur between adjacent electrode patterns of the external lead wiring electrodes of the liquid crystal display element.

According to the present invention, the conductive particles dispersed in the insulating adhesive have an average particle diameter of 2 μm to 30 μm.
Even if the pitch of the external lead-out wiring electrodes of the liquid crystal display element is as fine as, for example, about 200 μm, the external lead-out wiring electrodes of the liquid crystal display element may be damaged, such as cracks. In addition, it is possible to more reliably perform conductive bonding that does not cause a short circuit (conductive contact) between adjacent electrode patterns of the external lead wiring electrodes of the liquid crystal display element.

Further, in the present invention, the conductive particles are
In the initial stage where the compressive load is relatively small, it has the characteristics of a hard elastic sphere, and after the initial stage where the compressive load is relatively small, it suddenly collapses and has the property of plastic deformation. Using an anisotropic conductive adhesive containing the conductive particles, for example, a wiring electrode for external drawing (lower electrode extraction part) on a soft substrate such as a polymer film and a flexible wiring electrode for a drive circuit device Also in the case of anisotropic conductive bonding between the terminals, the anisotropic conductive bonding can be achieved more reliably without deforming or damaging the substrate or the electrodes.

Further, in the present invention, the surface of the conductive particles has irregularities sufficient to reach the conductive member by eliminating the insulating adhesive interposed between the conductive particles and the conductive member. In the case where the conductive member is formed, the conductive connection between the conductive particles and the conductive member can be more reliably ensured.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example of an anisotropic conductive adhesive according to the present invention.

FIG. 2 is a diagram showing a configuration example of a conductive particle according to the present invention.

[Figure 3] compressive deformation characteristics C ₂ or C ₃ of the compressive deformation characteristics C ₁ of the conductive particles 1 of the present invention conventional general conductive particles
It is a figure which shows roughly by contrasting with FIG.

FIG. 4 is a diagram illustrating a state of conductive particles before applying a compression weight F and a state of the conductive particles when a compression weight F is applied.

FIG. 5 is a diagram showing a more specific configuration example of a conductive particle according to the present invention.

FIG. 6 is a view showing a configuration example of a conductive particle according to the present invention.

FIGS. 7A and 7B are diagrams showing halftone images obtained by imaging the conductive particles of the present invention.

FIG. 8 is a diagram showing a halftone image of a conventional conductive particle (a conductive particle having almost no unevenness on the surface) for comparison with the conductive particles of FIGS. 7 (a) and 7 (b). is there.

FIG. 9 is a view schematically showing a bonding method using the anisotropic conductive adhesive of the present invention.

FIG. 10 is an enlarged view of an electrode portion bonded using the anisotropic conductive adhesive of the present invention.

FIG. 11 is a schematic plan view illustrating an example of a liquid crystal display element (liquid crystal display device).

FIG. 12 is a sectional view taken along line AA of FIG.

FIG. 13 is a schematic plan view showing another example of the liquid crystal display device (liquid crystal display device).

FIG. 14 is a cross-sectional view taken along line BB of FIG.

FIG. 15 is a view showing an example of a method for performing thermocompression bonding between an external lead-out wiring electrode of a liquid crystal display element substrate and a flexible wiring electrode terminal for a drive circuit device using the anisotropic conductive adhesive of the present invention. It is.

FIG. 16 is a diagram showing an example of a method for performing thermocompression bonding between an external lead-out wiring electrode of a liquid crystal display element substrate and a flexible wiring electrode terminal for a drive circuit device using the anisotropic conductive adhesive of the present invention. It is.

FIG. 17 is a diagram showing another configuration example of the anisotropic conductive adhesive according to the present invention.

FIG. 18 is a diagram showing a configuration of a method for connecting a conductive wiring having external compressive properties C ₁ , C ₂ , and C ₃ shown in FIG. It is a figure showing the outline at the time of performing conductive adhesion.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 conductive particles 2 core material particles 3 conductive layer 11 anisotropic conductive adhesive 12 insulating adhesive 16 filler 20 lower substrate 30 upper substrate 21 first polymer film substrate 31 second polymer film substrate 22, 32 ITO electrode 23, 33 Alignment film 24, 34 Polarizer 25 Reflector 26 Sealant 35 Gap material 42 External lead-out wiring electrode (lower electrode lead-out part) 43 External lead-out wiring electrode (upper electrode lead-out part) 51 Drive circuit board 52 electrode terminals

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H01B 5/16 H01B 5/16 H05K 1/14 H05K 1/14 C (72) Inventor Ikumi Sakata 130 Kamihirose, Sayama-shi, Saitama Soken Chemical Stock Association

Claims (10)

[Claims] 1. The method according to claim 1, wherein the conductive particles are contained in an insulating adhesive.
An anisotropic conductive adhesive characterized by being dispersed at a dispersion density of 0 / mm ^{2 to} 650 / mm ² . 2. The anisotropic conductive adhesive according to claim 1, wherein the average particle diameter of the conductive particles dispersed in the insulating adhesive is in a range of 2 μm to 30 μm. One side conductive adhesive. 3. The anisotropic conductive adhesive according to claim 1, wherein the conductive particles are hard elastic spheres having a compressive load of 2 gf / particle to 3 gf / particle at room temperature. It has properties and compressive load is 2 gf / particle to 3 gf
An anisotropic conductive adhesive characterized in that it has the property of crushing and plastically deforming when particles are reached. 4. The anisotropic conductive adhesive according to claim 1, wherein the anisotropic conductive adhesive is used to conductively bond a plurality of conductive members. When applying a predetermined compressive load to the anisotropic conductive adhesive between the conductive members, the irregularities on the surface of the conductive particles eliminate the insulating adhesive interposed between the conductive particles and the conductive member. An anisotropic conductive adhesive characterized in that it is formed in a sufficient size to reach a conductive member. 5. The anisotropically conductive adhesive according to claim 1, wherein the anisotropically conductive adhesive is formed as a film-like film. An anisotropic conductive adhesive, wherein the relation between the particle diameter D of the conductive particles and the film thickness T of the insulating adhesive is D ≧ T. 6. The anisotropic conductive material according to claim 1, wherein a wiring electrode for external drawing of a liquid crystal display element using a resin substrate and a flexible wiring electrode terminal for a predetermined device are provided. A liquid crystal display device which is connected by thermocompression bonding using an adhesive. 7. The liquid crystal display device according to claim 6, wherein
The liquid crystal display device according to claim 1, wherein the pitch of the external lead wiring electrodes of the liquid crystal display element is 150 μm to 400 μm. 8. A liquid crystal display device is manufactured by thermocompression-bonding an external lead wiring electrode of a liquid crystal display element using a resin substrate and a flexible wiring electrode terminal for a predetermined device using an anisotropic conductive adhesive. In the method of manufacturing a liquid crystal display device, the anisotropic conductive adhesive, in an insulating adhesive,
320 conductive particles having an average particle diameter of 20 μm / mm ²
A method for manufacturing a liquid crystal display device, characterized by using ones dispersed at a dispersion density of up to 600 / mm ² . 9. The method for manufacturing a liquid crystal display device according to claim 8, wherein the pitch of the external lead-out wiring electrodes of the liquid crystal display element is 150 μm to 400 μm. Production method. 10. The method for manufacturing a liquid crystal display device according to claim 8, wherein the flexible wiring electrode terminal for the predetermined device has a thickness of 18 μm, and the anisotropic conductive adhesive material has a thickness of 18 μm. Means that the thickness T of the insulating adhesive is 16 ± 3 μm before the thermocompression connection is made.
m, wherein a liquid crystal display device is manufactured.