KR100589586B1 - Insulated Conductive Particles and an Anisotropic Conductive Film Using the Same - Google Patents

Abstract

The insulating conductive fine particles according to the present invention comprises (A) insulating fine particles (34) composed of a crosslinked copolymer including conductive fine particles (33) and (B) functional monomers coated with a metal layer on the surface of the polymer fine particles. The conductive fine particles and the insulating adherent fine particles are discontinuously fixed by a mutual physical / chemical affinity to form a complex structure, and are dispersed and contained in the anisotropic conductive film 4 so that the insulating fine particles in the pressing direction in the circuit connection by pressing are moved / The electrical connection is made only in the pressing direction (z-axis direction), and the direction perpendicular to the pressing (x-axis and y-axis directions) is maintained.

Insulating Conductive Fine Particles, Anisotropic Conductive Adhesive Film, Immobilized, Surface Functionality, LCD Packaging

Description

Insulated Conductive Particles and an Anisotropic Conductive Film Using the Same}             

1 is an electrical connection cross-sectional view of an anisotropic conductive film using conventional coated insulating fine particles.

2 is a schematic cross-sectional view and a front view of the insulating conductive fine particles of the present invention.

3 is a schematic cross-sectional view of the anisotropic conductive film using the insulating conductive fine particles of the present invention.

It is sectional drawing of the electrical connection of the anisotropic conductive film using the insulating conductive fine particle of this invention.

Brief description of the main symbols in the drawings

1: coating insulating fine particle 2: circuit board

3: insulating conductive fine particles 4: anisotropic conductive film

5: liquid crystal display substrate 11: conductive particles

12: coated insulation layer 21: bump electrode

31: substrate fine particle layer 32: metal layer

33: conductive fine particles 34: insulating adherent fine particles

41: insulating adhesive 51: wiring pattern

Field of invention

The present invention relates to an insulating conductive fine particles and an anisotropic conductive film using the same. More specifically, the present invention relates to insulating conductive particles prepared by fixing insulating fixed particles on the surface of the conductive particles by physical adhesion and chemical affinity, and anisotropic conductive films prepared by applying the same, and used as an adhesive such as a liquid crystal display substrate. The present invention relates to an anisotropic conductive film which is electrically conductive only in the pressing direction (z-axis direction) and not conductive in the x-axis and y-axis directions by thermal compression during circuit connection.

Background of the Invention

In general, in order to electrically connect the connection electrode of the IC circuit board and the terminals of the board mounted on the circuit board, such as an LCD (Liquid Crystal Display) panel, anisotropic conductive connection should be made. As the anisotropic conductive connection material, a film adhesive in which conductive particles such as metal-coated resin fine particles or metal particles are dispersed in an insulating resin such as epoxy, urethane, or acrylic is widely used. When the prepared anisotropic conductive connection material is positioned between the electrode and the terminal to be connected, and heated and pressed, the electrically conductive material is generated in the z-axis direction in such a manner that conductive particles are sandwiched between the electrode and the terminal. In the direction, the insulating state is maintained by the insulating component of the insulating adhesive.

Recently, in LCD packaging requiring such anisotropic conductive connection, the development of LCD technology requires the improvement of connection reliability, miniaturization of connection pitch, and miniaturization of IC bump, and the number of leads printed on the substrate. The trend is increasing. In accordance with such technical requirements, it is necessary to reduce the particle size of the conductive particles contained in the anisotropic conductive film, and research and development to increase the compounding amount of the conductive particles in order to improve the connection reliability has been continued. However, due to the reduced particle size and the increased particle density of the conductive particles used, the aggregation or bridge of the particles occurs, which results in frequent nonuniformity of the connection or short circuit between the patterns.

As such, various methods have been proposed to solve the problem in which a short circuit occurs. In Japanese Patent Laid-Open Nos. 62-40183, JP-A 62-176139, JP-A 3-46774, JP-A 4-174980, JP-A 7-105716, 2001-195921, 2003-313459, and the like. Using microcapsule, spray-drying, coacervation, electrostatic coalescing, metathesis polymerization, physical / mechanical hybridization, etc. Disclosed is a method of partially or continuously covering the surface of conductive particles with an insulating coating material such as an insulating polymer resin. In addition, Japanese Patent Application Laid-open No. Hei 2-204917 discloses a technique for insulating the conductive particles by coating the entire surface of the conductive particles with an electrically insulating metal oxide.

However, in the case of the coated insulating conductive fine particles coated with the insulating resin with an insulating resin such as Japanese Patent Laid-Open No. 62-40183, the conductive layer of the conductive particles is formed by collapse of the insulating layer when the anisotropic conductive film is thermally compressed. Exposed electrical connections. At this time, even if the insulating layer collapses between the bumps and the conductive particles or between the pattern and the conductive particles, the collapsed insulating layer is not easily removed, so that long-term energization is performed when a sufficient amount of conductive particles are not connected on the bumps or the patterns. It is difficult to secure reliability. Furthermore, in the case of the fine particles coated with the thermosetting insulating resin, fine bumps or damage to the pattern may be caused when the insulating layer collapses. On the other hand, in recent years, a low temperature fast curing type anisotropic conductive film and bonding process have been adopted in order to shorten the process time and reduce the cost while not burdening the electrode and the module. In this case, pressurization at a low temperature for a short time makes it more difficult to sufficiently collapse and remove the coated insulating layer, which results in a problem of deteriorating connection reliability.

In Japanese Patent Laid-Open No. 58-223953, Japanese Patent Laid-Open No. 6-333965, Japanese Patent Laid-Open Nos. 6-349339, 2001-164232, etc., in addition to conductive particles, insulating organic or inorganic particles, insulating fibrous fillers, etc. are separately added. Thus, a method for preventing agglomeration between particles and further improving connection reliability of an anisotropic conductive adhesive is disclosed.

As described in Japanese Patent Application Laid-Open No. 58-223953 and the like, in order to prevent aggregation of conductive particles by adding additional insulating organic or inorganic particles or fibrous fillers in addition to the conductive particles, the amount of addition of the conductive particles is increased. To meet the limitation of the, further exposed to various problems in the film forming process of the anisotropic conductive adhesive, there is a problem that long-term connection reliability is lowered even after the connection.

As another conventional method, a method for preventing the conductive particles from flowing out from the electrode when the connection is made by multilayering the anisotropic conductive film is also tried. However, this method is very limited compared to the case of using the insulated fine particles due to the time-consuming problem of manufacturing and other manufacturing process variables.

In order to solve the above problems, the inventors of the present invention physically improve the solvent resistance and dispersion stability in the adhesive resin component in immobilizing the insulation-fixed fine particles, which can be displaced during compression, on the surfaces of the conductive fine particles. It is to develop an insulating conductive fine particles imparted simultaneously with adhesion and chemical binding, and to develop an anisotropic conductive film having high current conduction and insulation reliability using the insulating conductive fine particles.

 An object of the present invention is to provide an insulating conductive fine particles having an excellent conduction reliability in the z-axis direction by the decomposition of the insulating layer easily when the anisotropic conductive film is pressed.

Another object of the present invention is to prevent secondary agglomeration occurring between the insulating conductive particles to prevent short circuits between adjacent bumps or wiring patterns to provide insulating conductive particles having excellent insulation reliability in the xy plane direction. It is for.

Another object of the present invention is to provide insulating conductive fine particles having excellent solvent resistance in the adhesive resin composition.

It is another object of the present invention to provide insulating conductive fine particles suitable for fine-pitching of wiring patterns and low temperature rapid curing of anisotropic conductive adhesives.

Still another object of the present invention is to provide a method for producing insulating conductive fine particles having excellent insulation reliability and current carrying reliability.

Still another object of the present invention is to provide an anisotropic conductive film containing insulating conductive fine particles having excellent insulation reliability and conduction reliability.

The above and other objects of the present invention can be achieved by the present invention described below.

Summary of the Invention

The insulating conductive fine particles according to the present invention comprises (A) insulating fine particles 34 composed of a crosslinked copolymer including conductive fine particles 33 coated with a metal layer on the surface of the polymer particles and (B) a functional polymerizable monomer. The conductive fine particles and the insulating adherent fine particles are discontinuously fixed by the mutual physical / chemical affinity to form a complex structure, and are dispersed and contained in the anisotropic conductive film 4 so that the insulating fine particles in the pressing direction when the circuit is connected by pressing are formed. The electrical connection is made only in the pressing direction (z-axis direction) by moving / removing, and the direction perpendicular to the pressing (x-axis and y-axis directions) is maintained in insulation.

Hereinafter, with reference to the accompanying drawings, the contents of the present invention will be described in detail.

Detailed Description of the Invention

1 is a cross-sectional view of an electrical connection of an anisotropic conductive film using conventional insulating conductive fine particles. The coated insulating fine particles 1 cover the outermost layer of the conductive particles 11 with the insulating layer 12 and are designed to exhibit anisotropic conductivity by compression. However, due to the pressurization, the insulating layer 12 may not be sufficiently collapsed or removed, and the insulating layer 12 may be thinned or the insulating material remains, thereby lowering the power supply reliability. Furthermore, in order to secure the electricity supply reliability, a larger number of coated insulating particles 1 must be trapped between the electrodes. In this case, when the wiring pattern is fine pitched, a large number of coated insulating particles 1 are trapped. There is a limit, and the insulation and conduction reliability is inevitably deteriorated.

Fig. 2 shows a cross section and a surface of the insulating conductive fine particles 3 according to the present invention. The insulating conductive fine particles 3 of the present invention consist of the conductive fine particles 33 and the insulating fixing fine particles 34 discontinuously fixed to the surface thereof.

The conductive fine particles 33 used in the present invention use conductive fine particles prepared by coating one or more metals 32 on the surface of the polymer resin fine particles 31. The metal is applicable as long as it is a conductive metal such as gold, nickel, palladium (Pd) or silver (Ag). The conductive fine particles 33 of the present invention are preferably monodisperse fine particles having a size of about 2 to 10 μm, and the particle diameter of each of the conductive fine particles 33 is in the range of 90 to 110% of the average particle diameter of all the conductive fine particles 33. It is preferable that the microparticles | fine-particles which have a particle diameter of 80 weight% or more. When the particle diameter of the conductive fine particles 33 is less than 80% by weight in the range of 90 to 110% of the average particle diameter, the uniformity of the particle diameter becomes too low, which leads to an increase in the nonuniformity of the connection at the time of electrode connection and to a rapid decrease in the electrical conduction reliability.

The insulating fixable fine particles 34 of the present invention are composed of hard organic polymer particles, inorganic fine particles, or organic / inorganic composite particles insoluble in the insulating adhesive resin component. The rigid meaning used in the present invention means that the spherical shape is not significantly deformed by external force, impact force, friction force, etc., and does not dissolve in insulating resin adhesives and other solvents when physical / mechanical complexation is applied.

In addition, the insulating fixing fine particles 34 of the present invention have a hard property and contain a functional group having a strong bond and affinity with a metal. A typical metal affinity functional group is a thiol (-SH) group, but since the thiol group acts as a radical scavenger, it may cause problems in film curing, etc., to use the insulating conductive fine particles introduced therein for an anisotropic conductive adhesive film. . Therefore, various functional groups including other nucleophilic groups besides thiol groups can be advantageously used as metal affinity functional groups, for example, carboxyl groups, hydroxy groups, glycol groups, aldehyde groups, oxazole groups, amine groups, amide groups, imide groups , Nitro groups, nitrile groups, sulfone groups and the like.

Insulating adherent fine particles 34 according to the present invention are immobilized on the surface of the conductive fine particles 33 by physical / mechanical complexing, and at the same time, the chemically bonded by the metal affinity functional group is formed on the surfaces of the two fine particles in contact with each other. The fine particles 3 are produced. The immobilization of the insulating fixable fine particles 34 according to the present invention basically imparts physical adhesion to the metal surface by the slight deformation of the fine particle surface according to the physical / mechanical external force, and at the same time the chemical bonding force by the functional group of the fine particle surface. Even if physical dissolution of the bonded part is achieved, it is possible that the immobilized adhesion of the particles is not removed by binding the metal-particle interface.

The insulating adherent fine particles 34 of the present invention have a diameter of 1/30 to 1/5 of the conductive fine particles 33 and are discontinuous at a density of ¹ to 550 pieces / μm ² on the surface of the conductive fine particles 33. It is preferred to be immobilized with. Here, the number of insulating fixed fine particles N _max in the case where the spherical insulating fixed fine particles (diameter d) are regularly arranged in the closest packed state on the surface of the conductive fine particles (diameter D) is as shown in the following equation (1).

Also represents a fixed number N _max Contrast real-stage ratio of immobilized number per particle-filled state of the insulating fine particles fixed rate highest density when the insulating fixative particles (34) of small diameter arranged on the assigned surface of Sir conductive particle (33). In this invention, it is preferable that the insulation particle fixation rate of an insulating electroconductive fine particle is 50% or more, More preferably, it is good to arrange | position uniformly at 80% or more.

When the insulating particle fixation rate of the insulating conductive fine particles 3 is less than 50%, since the insulating fine particles do not sufficiently cover the surface of the conductive fine particles 33, a bridge between the uncovered conductive surfaces of the conductive fine particles 33 is used. ), A short circuit between patterns is likely to occur.

In addition, the insulating adherent fine particles 30 should have an aspect ratio of less than 1.5 and a coefficient of variation of 30% or less. Here, the aspect ratio is the ratio of the longest axis diameter to the shortest axis diameter of a single particle, and the coefficient of variation refers to the standard deviation of the particle size divided by the average particle diameter, where the aspect ratio is 1.5 or more or the coefficient of variation exceeds 30%. When the fine particles are immobilized on the surface of the conductive particles, when they are positioned between the electrodes by compression, the removal of the insulating adherent fine particles becomes uneven, which may cause a problem of deterioration of the energization reliability.

The insulating conductive fine particles 3 according to the present invention are manufactured by manufacturing the insulating fixing fine particles 34 and immobilizing them physically and chemically on the surface of the conductive fine particles 33.

Synthesis of Insulating Adhesive Particulates

Insulating adherent microparticles | fine-particles 34 used for this invention are hard and contain the metal affinity functional group in the particle surface. Organic insulating particles, inorganic fine particles, organic / inorganic composite particles, and the like may be used as the material of the insulating fixed particles, and in the present invention, particularly, organic polymer particles may be prepared and used as the insulating fixed particles 34. The material is not limited to a particular kind.

The organic polymer material used as the insulating fixing fine particles 34 of the present invention may be used alone or crosslinked with a certain amount of the crosslinkable polymerizable monomer and one or more general polymerizable monomers in order to have rigidity. It may be composed of a copolymer, but in order to have a metal affinity functional group on the surface of the microparticles, it is preferable to copolymerize at least one functional polymerizable monomer with the monomers. Such organic polymer-based insulating fixed particles are not particularly limited in their manufacturing method, but may be typically produced by emulsion polymerization, oil-free polymerization, or dispersion polymerization.

The crosslinkable polymerizable polymer is capable of radical polymerization, and specific examples thereof include divinylbenzene, 1,4-divinyloxybutane, divinylsulphone, diallyl phthalate, diallyl acrylamide, triallyl (iso) cyanurate, Allyl compounds such as trially trimellitate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerylyl Tritol tri (meth) acrylate, pentaaryl tritol di (de) acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol Acrylic compounds, such as penta (meth) acrylate and glycerol tri (meth) acrylate, etc. can be used.

The crosslinkable polymerizable monomer is copolymerized and used within the range of 0.1 to 99.9% by weight with respect to the total monomer content, and more preferably 2 to 80% by weight in order to provide the hard insulating fixed particles 34.

The general polymerizable monomer is also capable of radical polymerization, and specific examples thereof include styrene monomers such as styrene, ethyl vinyl benzene, α-methyl styrene, and m-chloromethyl styrene, methyl (meth) acrylate, and ethyl (meth). Acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl ( Meta) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl ether, allyl butyl ether and the like.

The functional polymerizable monomer is also capable of radical polymerization, and specific examples thereof include unsaturated carboxylic acid, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (including (meth) acrylic acid, maleic acid, itaconic acid, and the like). Meth) acrylate, hydroxybutyl (meth) acrylate, polyethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, Allyl glycidyl ether, 2-isopropenyl-2-oxazoline, diethylaminoethyl (meth) acrylate, alkyl (meth) acrylamide, 4-vinylpyridine, N-methylol acrylamide, (meth) acrylic Loyl chloride, (meth) acrylonitrile, styrene sulfonic acid, sodium styrene sulfonate and sulfonic acid derivatives thereof and the like.

In addition, the functional polymerizable monomer is copolymerized and used within the range of about 0.1 to 50% by weight relative to the total monomers in order to impart adhesion to the metal while maintaining the rigidity of the insulating fixing fine particles 34.

Insulating adherent particles 34 obtained in this manner may exhibit various morphologies such as fully spherical, core / shell, raspberry or hemispherical, all of which are in accordance with the present invention. It is applicable to manufacturing the insulating conductive fine particles 3.

Immobilization of Insulating Adhesive Particulates

It is a step of fixing the insulating fixing fine particles 34 prepared by the above method on the surface of the conductive fine particles 33. As a method of immobilization, a physical / mechanical hybridization method is used. A detailed physical / mechanical hybridization method is disclosed in Microcapsule (3rd edition, Japanese Sampo Publishing Co., Ltd., issued on January 20, 1995).

The present invention immobilizes the insulating fixed particles 34 on the surface of the conductive fine particles 33 by using a physical / mechanical compounding method, which is a method of mixing materials in a high-speed air stream dry and processing them by physical / chemical energy. As a matter of fact, in relation to the rotational speed of the apparatus, the treatment time, the mixing ratio and the material of the material, and the like, there is an advantage that uniform surface treatment in the form of coating or immobilization can be performed in a much shorter time than the wet compounding method.

The insulating fixing fine particles 34 immobilized in the above-described manner are partially maintained in contact with the metal surface of the conductive fine particles 33 by partial micro deformation / fusion, while largely maintaining the original morphology. Physical bonding is performed and at the same time bonding is performed by strong chemical attraction with the metal by the functional group. Due to the physical / chemical binding force of the interparticle interface, the insulating adherent fine particles 34 are fixed to the surface of the conductive fine particles 33. Finally, the insulating conductive fine particles 3 of the present invention have a form in which the insulating fixing fine particles 34 which maintain their original spherical shape are uniformly fixed on the surface of the conductive fine particles 33.

The insulating conductive particles 3 according to the present invention are fixed to the surface of the conductive fine particles 33 discontinuously fixed at a density of ¹ to 550 particles / μm ² , and the insulating fixation rate is 50%. As mentioned above, it is preferable that the diameter of the said insulating fixed particle | grains 34 is 1/100-1/5 of the diameter of the said electroconductive fine particles 31. As shown in FIG. If the diameter of the insulating adherent fine particles 34 is less than 1/100 of the diameter of the conductive fine particles 31, the gap between the conductive fine particles 31 is sufficient so that the insulating fine particles impart electrical insulation upon the aggregation of the conductive fine particles 31. Can not be sufficiently maintained, thereby lowering the electrical insulation reliability of the connection structure. On the other hand, when the diameter ratio between the said fine particles exceeds 1/5, it is difficult for the insulating fixable microparticles | fine-particles 34 to be fixed uniformly to the electroconductive fine particles 31, and it is easy to finally reduce insulation reliability.

3 is a schematic cross-sectional view of the anisotropic conductive adhesive film 4 in which the insulating conductive fine particles 3 according to the present invention are dispersed in the insulating adhesive 41 component.

As shown in Fig. 3, in the anisotropic conductive adhesive film 4 according to the present invention, the insulating conductive fine particles 3 according to the present invention are uniformly dispersed in the insulating adhesive 41 component. Even after the insulating conductive fine particles 3 are dispersed in the insulating adhesive 41 component, since the insulating fixing fine particles 34 are immobilized on the surface of the conductive fine particles 33 by physical / chemical cohesion, the insulating conductive fine particles 3 ) Will stably maintain its morphology.

The content of the insulating conductive fine particles 3 contained in the anisotropic conductive film 4 according to the present invention is preferably 5,000 to 80,000 pieces / mm 2, and more preferably 10,000 to 50,000 pieces / mm 2.

When the content of the insulating conductive fine particles 3 in the anisotropic conductive film 4 is less than 5,000 pieces / mm < 2 >, the number of fine particles remaining on the electrode or the bump during electrode connection is too small, so that the conduction reliability and the connection reliability of the connecting structure as a whole are reduced. It is easy to be degraded. In addition, when the content of the insulating conductive fine particles (3) exceeds 80,000 pieces / mm2, the thermal flow characteristics of the anisotropic conductive film (4) during the connection of the electrode by heat compression greatly affects the nonuniformity of the connection, On the other hand, it is easy to form bridges between the insulating conductive fine particles 3 between the patterns, and the probability of contacting the conductive surfaces with each other is greatly increased, thereby lowering the electrical insulation reliability.

FIG. 4 shows an anisotropic conductive adhesive film 4 containing the insulating conductive fine particles 3 according to the present invention pressed between the substrates 2 and 5 so as to be energized between the electrode 21 and the wiring pattern 51. A schematic cross sectional view showing an electrical connection structure.

As shown in Fig. 4, the circuit board 2 and the wiring pattern 51 on which the bump electrodes 21 are formed are formed on the anisotropic conductive adhesive film 4 containing the insulating conductive fine particles 3 of the present invention. The electrical connection between the circuit board 2 and the liquid crystal display panel 5 is achieved by pressing between the liquid crystal display panels 5. When the insulating conductive fine particles 3 according to the present invention are compressed between the bump electrode 21 and the wiring pattern 51, the insulating fixed particles 34 fixed to the surface of the insulating conductive fine particles 3 are compressed. The conductive fine particles 33 are electrically connected to the bump electrode 21 and the wiring pattern 51 by being moved / removed at the original position by the action of the same. Therefore, high energization reliability in the z-axis direction can be obtained. (3) The insulating conductive fine particles can be moved / removed at their original positions even by the action of heating and pressing.

Further, as shown in Fig. 4, even after the anisotropic conductive adhesive film 4 is pressed between the substrates 2 and 5, even if the insulating conductive fine particles 3 form a bridge between neighboring electrodes by aggregation, the conductive The electrical contact between the insulating conductive fine particles 3 is prevented by the space occupancy of the insulating fixing fine particles 34 immobilized on the surface of the fine particles 33. As a result, the possibility of the occurrence of a short circuit between neighboring electrodes is cut off and the energization in the xy plane direction is prevented, thus showing high insulation reliability in the xy plane direction.

The present invention will be further illustrated by the following examples, which are merely illustrative of the present invention and are not intended to limit or limit the scope of the present invention.

Example 1

Preparation of Insulating Adhesive Particulates

In Example 1 of the present invention, hard functional insulating fixed particles were prepared by the emulsion-free polymerization method, and then the insulating conductive fine particles were immobilized on the surface of the conductive fine particles to prepare insulating conductive fine particles.

First, deionized water was quantified in a reactor, stirred at 70 ° C. for 30 minutes in a nitrogen atmosphere, and methyl methacrylate (MMA), divinylbenzene (DVB), and acrylic acid (Acrylic acid, AA) were respectively used as monomers. 20:10 was added quantitatively and stirred for 10 minutes. Thereafter, an aqueous solution of potassium persulfate (potassium persulfate, KPS) was added thereto to initiate a polymerization reaction, and the emulsion-free polymerization was performed at 70 ° C. and 250 to 400 rpm for 10 hours. The obtained polymer fine particles were washed several times with deionized water and lyophilized. The average particle diameter of the synthesized polymer microparticles was measured by light scattering particle size analyzer. Table 1 shows the components and average particle diameters of the insulating fixed particles obtained by the above method.

Preparation of Insulating Conductive Fine Particles

Thus prepared insulating adherent fine particles were prepared on the surface of conductive fine particles having an average particle diameter of 4.3 μm by Ni / Au plating on the surface of monodispersed organic polymer fine particles using a hybridizer NHS-0 manufactured by a Japanese machine tool. Immobilized by mechanical method. Surface fixation density (E.A / µm 2) and fixation rate (%) of the prepared insulating conductive fine particles were measured using a scanning electron micrograph, and the results are shown in Table 1.

To evaluate the solvent resistance of the prepared insulating conductive fine particles, a predetermined amount of insulating conductive fine particles were dispersed in a mixed solvent of toluene and methyl ethyl ketone, and stirred for 5 hours, and then only the fine particles were recovered and dried, compared to the fine particle weight before the solvent treatment. It can obtain by measuring the microparticle weight ratio after a solvent process. Table 1 shows the results of evaluating the solvent resistance of the insulating conductive fine particles thus obtained.

Fabrication and Evaluation of Anisotropic Conductive Junctions

15 parts by weight of bisphenol A epoxy resin having an epoxy equivalent of 6000 and 7 parts by weight of 2-methylimidazole as a curing agent were dissolved in a mixed solvent of toluene and methyl ethyl ketone, and then the insulating conductive fine particles prepared were 25,000 pieces / mm 2. It was dispersed well with the silane coupling agent, and then coated on a release PET film and dried to prepare a 25 μm thick film. The anisotropic conductive adhesive film thus prepared was formed using a bump resin having a thickness of 40 μm, an IC chip size of 6 mm × 6 mm, and a 0.8 mm thick BT resin substrate having a 8 μm thick wiring pattern formed of copper and gold plating. ) To 150 占 퐉, and an anisotropic conductive film according to the present invention was described between the IC chip and the substrate, and the electrical connection structure was produced by heating, pressing and compressing for 10 seconds under a temperature of 180 ° C and a pressure of 3 MPa.

Subsequently, when measuring the electrical resistance between the upper and lower electrodes of the said connection sample, the electrical resistance between 20 adjacent upper and lower electrodes was measured, the average value was computed, and it represented as connection resistance, and the result is shown in Table 2.

In addition, a bump substrate having a thickness of 35 μm × 75 μm, a bump height of 20 μm, an IC chip size of 6 mm × 6 mm, a transparent substrate having a wiring pattern formed of glass indium tin oxide, a pitch of 65 μm, and Insulation reliability evaluation was carried out at a line of 70 µm. A transparent substrate was used to confirm the occurrence of a short under a microscope. Measure the electrical resistance between 20 adjacent electrodes, and measure ◎ when the resistance is 10 ¹⁰ Ω or more, △ when 10 ⁹ to ^{10 10} Ω, and X when the resistance is less than 10 ⁹ Ω. Shown in

Example 2

Insulating adherent fine particles of Example 2 were prepared in the same manner as in Example 1 except that the diameter of the fine particles was changed to 0.39 μm, and the insulating conductivity was the same as in Example 1 using the prepared insulating adherent fine particles. Fine particles and anisotropic conductive adhesive films were prepared to evaluate solvent resistance, connection resistance at the time of energization, and insulation reliability. The evaluation results are shown in Table 1.

Example 3

Insulating adherent microparticles of Example 3 were prepared in the same manner as in Example 1 except that the functional polymerizable monomer was changed from acrylic acid to methacrylic acid (MA). Insulating conductive fine particles and anisotropic conductive adhesive film were prepared in the same manner as in Example 1, and solvent resistance, connection resistance at the time of energization, and insulation reliability evaluation were performed. The results are shown in Table 1.

Example 4

Insulating adherent fine particles of Example 4 were prepared in the same manner as in Example 1 except that the functional polymerizable monomer was changed from acrylic acid to styrene sulfonic acid (SSA). Insulating conductive fine particles and anisotropic conductive adhesive film were prepared in the same manner as in Example 1, and solvent resistance, connection resistance at the time of energization, and insulation reliability evaluation were performed. The results are shown in Table 1.

Comparative Example 1

Insulating adherent microparticles of Comparative Example 1 were prepared in the same manner as in Example 1, except that the diameter was 0.25 μm and the functional crosslinkable monomer was not used, as described in Table 1. The insulating conductive fine particles and the anisotropic conductive adhesive film were prepared in the same manner as in Example 1 using the insulating fixing fine particles of, to evaluate solvent resistance, connection resistance at the time of energization, and insulation reliability. The results are shown in Table 1.

Comparative Example 2

Comparative Example 2 excludes the method of immobilization by the physical / mechanical method used in Example 1 in the method of immobilizing the insulating fixed particles on the surface of the conductive fine particles and did not use a functional crosslinkable monomer as shown in Table 1. Insulating conductive fine particles were prepared by adding and stirring conductive fine particles in water or organic solvent dispersion in which the insulating fine particles were dispersed, and simply immobilizing by chemical adsorption. Anisotropic conductive adhesive films were prepared in the same manner as in Example 1 Was prepared, and evaluation of solvent resistance, connection resistance at the time of energization, and insulation reliability was performed. The results are shown in Table 1.

division Example Comparative Example One 2 3 4 One 2 Insulation adhesive particles  Functional monomer AA AA MA SSA - -  Average particle size (㎛) 0.20 0.39 0.20 0.21 0.25 0.20 Insulation conductive fine particles Immobilization Density (pieces / μm ² ) 8.2 2.2 8.6 7.5 5.3 8.0  % Fixed 90 85 95 90 90 90  Solvent resistance (%) 98 92 97 95 45 63 Anisotropic Conductive Connections  Connection resistance (Ω) 0.9 0.9 1.0 0.9 0.8 0.9  Insulation Reliability ◎ ◎ ◎ ◎ × ×

As can be seen from Examples 1 to 4 and Comparative Examples 1 to 2, the anisotropic conductive adhesive film containing the insulating conductive fine particles physically and chemically immobilized using the insulating fixed fine particles according to the present invention has a simple surface. Compared with the insulating conductive fine particles only by physical immobilization and the immobilized insulating conductive fine particles only by chemical adsorption, excellent solvent resistance and insulation reliability were shown.

The present invention not only provides the effect of having excellent solvent resistance by physically and chemically stably fixing a plurality of functional insulating adherent particles on the surface of the conductive fine particles, but also prevents direct contact between the conductive fine particles to prevent adjacent bumps or wiring. The present invention has the effect of providing an anisotropically conductive adhesive film and insulating conductive particles having the same, having excellent insulation reliability in the xy plane direction and excellent conduction reliability in the z-axis direction by preventing a short circuit between the patterns.

Simple modifications and variations of the present invention can be readily used by those skilled in the art, and all such variations or modifications can be considered to be included within the scope of the present invention.

Claims (8)

(A) conductive fine particles 33 having a metal layer coated on the surface of the polymer fine particles; and (B) insulating adherent fine particles 34 composed of a crosslinked copolymer comprising a functional polymerizable monomer; And the conductive fine particles and the insulating fixed fine particles are discontinuously fixed by the mutual physical / chemical affinity and have a complex structure, and are dispersed and contained in the anisotropic conductive film 4 so as to be in the pressing direction when connecting the circuit by pressure. Insulating conductive fine particles (3), in which insulating fine particles are moved / removed so that electrical connection is made only in the pressing direction (z-axis direction), and the vertical direction (x-axis and y-axis directions) with respect to pressing is maintained. The circuit according to claim 1, wherein the conductive fine particles and the insulating fixed fine particles have a structure in which they are discontinuously fixed by a mutual physical / chemical affinity and have a complex structure, and are dispersed and contained in the anisotropic conductive film (4). The insulating fine particles in the pressing direction are moved / removed so that electrical connection is made only in the pressing direction (z-axis direction), and the vertical direction (x-axis and y-axis directions) with respect to pressing is applied to the insulating conductive fine particles to maintain insulation. 3). According to claim 1, wherein the insulating fixed fine particles 34 is at least one functional group selected from the group consisting of carboxyl group, hydroxy group, glycol group, aldehyde group, oxazole group, amine group, amide group, imide group, nitro group, nitrile group, sulfone group Insulating conductive fine particles, characterized in that it has a. The insulating conductive fine particles according to claim 1, wherein the immobilization rate of the insulating adherent fine particles (34) is 50% or more. The insulating conductive fine particles according to claim 1, wherein the insulating fixed fine particles (34) have an aspect ratio of less than 1.5 and a coefficient of variation of 30% or less. The method of claim 1, wherein the functional polymerizable monomer is an unsaturated carboxylic acid containing 2-methacrylic acid, maleic acid, itaconic acid, etc., 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth ) Acrylate, hydroxybutyl (meth) acrylate, polyethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, allyl Glycidyl ether, 2-isopropenyl-2-oxazoline, diethylaminoethyl (meth) acrylate, alkyl (meth) acrylamide, 4-vinylpyridine, N-methylol acrylamide, (meth) acrylo Insulating conductive fine particles, characterized in that at least one selected from the group consisting of monochloride, (meth) acrylonitrile, styrene sulfonic acid, sodium styrene sulfonate, and sulfonic acid derivatives thereof. The method of claim 1, wherein the conductive fine particles 33 is coated with at least one metal layer on the surface of the polymer resin fine particles, the particle size of the conductive fine particles 80 to 80% of the fine particles in the range of 90 to 110% of the average particle diameter of the total conductive fine particles Insulating conductive fine particles, characterized in that more than%. The insulating conductive fine particles of Claims 1-7 are disperse | distributed in insulating adhesive resin, The anisotropically conductive adhesive film characterized by the above-mentioned.

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