KR100543748B1 - Method Of Preparing Electroconductive Particles Contained Anisotropic Conductive Film - Google Patents

Abstract

In the method for producing conductive fine particles for anisotropic conductive films according to the present invention, a metal layer is plated on a surface of a polymer core material fine particle, and a resin for forming the polymer core material fine particle and an insulating layer plated with a metal layer in a rotary container of a dry oval fine particle composite machine. The fine particles are added, and the rotating container and the rotor are rotated in opposite directions to each other, and the fine particles for forming the insulating layer are attached to the surface of the fine metal plated metal layer, thereby forming an insulating layer.

Anisotropic conductive film, conductive fine particles, insulating layer, dry oval fine particle composite machine

Description

Method for preparing conductive fine particles for anisotropic conductive film {Method Of Preparing Electroconductive Particles Contained Anisotropic Conductive Film}             

Figure 1 shows a cross section of the conductive fine particles prepared in accordance with an embodiment of the present invention.

Figure 2 shows a cross section of the conductive fine particles prepared according to another embodiment of the present invention.

3 is a schematic cross-sectional view of a dry elliptical particulate composite device for forming an insulating layer of conductive fine particles according to the present invention.

4 is a schematic cross-sectional view taken along the line AA ′ of FIG. 3.

5 is a cross-sectional view schematically illustrating a process of forming an insulating layer on the core material fine particles using a dry elliptical fine particle composite machine used in the present invention.

Figure 6a is a scanning electron microscope (Scanning Electron Microscpoe: S.E.M.) photograph of the surface of the conductive fine particles prepared according to the manufacturing method of the present invention at a magnification of 5,000 times.

6B is an enlarged S.E.M. photograph at a magnification of 15,000 times the surface of the conductive fine particles prepared according to the manufacturing method of the present invention.

Brief description of the main symbols in the drawing

1: Conductive fine particles 2: Dry oval fine particle composite machine

11: Polymer core material particulate 11 ': Metal core material particulate

12: metal layer 13: insulation layer

21: rotating container 22: rotor

23: torque meter 24: axis

25: gap

Field of invention

This invention relates to the manufacturing method of the electroconductive fine particle used for an anisotropically conductive film. More specifically, the present invention relates to a method for producing conductive fine particles having electrical conductivity in the z-axis direction by crushing by forming an insulating layer on the outermost layer of the conductive fine particles using a dry elliptical fine particle composite machine.

Background of the Invention

In general, anisotropic films are positioned between the connecting parts and heated and pressed. In this case, terminals adjacent in the direction parallel to the substrate (x-y plane direction) do not conduct electricity, but terminals adjacent in the vertical direction (z-axis direction) have conductivity. This conductive function is performed by the conductive fine particles dispersed in the adhesive material in the film, the conductive fine particles are usually prepared by coating a metal material on the core (core).

Japanese Patent Laid-Open Nos. 52-147797, 61-277104, 61-277105, 62-185749, 63-190204, 1-225776, 1-247501, 44-147513 In such a case, the conductive fine particles described above are disclosed. However, in the case of the conductive fine particles consisting only of a plating layer on the core material (core), there is a disadvantage in that a precision circuit is always exposed to a risk of short circuit between adjacent terminals.

In order to solve this problem, the present inventors formed an insulating layer in the outermost layers of the conductive fine particles in patent applications 2003-78506 and 2003-76446 so that they are energized in the z-axis direction only when the particles are collapsed between the electrodes. The invention has been applied for insulating conductive fine particles and a method of manufacturing the same. However, since the process of forming the outermost insulating layer in the patent application is a dry process using the high speed air flow of the hybridization system, the film forming rate is lowered due to the unreacted residual particles inside the rotor during the reaction, and the air flow is used. This requires a significant RPM and power from the device.

In order to solve the drawbacks of the hybridization system process, the present inventors use a dry elliptical particulate composite device (theta-composer) to fix the metal core material particles or the polymer core material particles to the outermost surface of the metal-coated particles. By forming the insulating layer by using a dry elliptic fine particle composite machine, it is to develop a method for producing conductive fine particles which can form the outermost insulating layer more uniformly while increasing the film formation rate.

An object of the present invention is to provide a method for producing conductive fine particles for anisotropic conductive films exhibiting electrical conductivity in the z-axis direction by crushing.

Another object of the present invention is to provide a method for producing conductive fine particles for anisotropic conductive film that can form a uniform thickness of the coating layer of the insulating layer by forming an insulating layer on the outermost portion of the core material particles using a dry oval fine particle composite machine. will be.

Still another object of the present invention is to provide a method for producing conductive fine particles for anisotropic conductive films that does not require a solvent removal process in a conventional wet process because the process of forming the insulating layer is dry.

Still another object of the present invention is to provide a method for producing conductive fine particles for anisotropic conductive films having better stability of core particles and uniformity of insulating layer than when using a hybridization system.

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

Summary of the Invention

In the method for producing conductive fine particles for anisotropic conductive films according to the present invention, a metal layer is plated on a surface of a polymer core material fine particle, and a resin for forming the polymer core material fine particle and an insulating layer plated with a metal layer in a rotary container of a dry oval fine particle composite machine. The fine particles are added, and the rotating container and the rotor are rotated in opposite directions to each other, and the fine particles for forming the insulating layer are attached to the surface of the fine metal plated metal layer, thereby forming an insulating layer.

On the other hand, the manufacturing method of the conductive fine particles for the anisotropic conductive film according to the present invention includes the case of using the metal particles without using the polymer core material fine particles, the manufacturing method in this case is a metal core material in the rotary container of the dry oval fine particle composite machine Injecting the material fine particles and the resin fine particles for forming the insulating layer, and by rotating the rotating vessel and the rotor in the opposite direction to each other, the resin fine particles for forming the insulating layer is attached to the surface of the metal core material fine particles to form an insulating layer Consists of steps.

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 the conductive fine particles prepared according to the method for producing conductive fine particles for the anisotropic conductive film according to the present invention, Figure 2 is a cross-sectional view of the conductive fine particles prepared according to another embodiment of the present invention.

As shown in FIG. 1, the conductive fine particles 1 manufactured according to the manufacturing method of the present invention are manufactured by forming a metal layer on the polymer core material fine particles 11 and then forming an insulating layer on the surface of the metal layer. On the other hand, as shown in Figure 2 as another embodiment of the present invention, the conductive fine particles (1 ') instead of coating a metal layer on the polymer core material fine particles using the metal core material fine particles (11') insulating layer on the surface It is also possible to manufacture by forming (13). Hereinafter, description of each step is as follows.

Formation of core material particles and metal layer

Polymeric core material fine particles used in the present invention can be appropriately selected in the range of 0.1 to 10 ㎛ average particle diameter as spherical fine particles. Specific examples of the polymer core material include thermosetting polymer resins such as phenol resins, urea resins, melamine resins, fluorine resins, polyester resins, epoxy resins, silicone resins, polyimide resins, polyurethane resins, propylene resins, polyolefin resins, or the like. Polyethylene resin, polypropylene resin, polybutylene resin, polymethacrylic resin, polystyrene resin, acrylonitrile-styrene resin, acrylonitrile-styrene-butadiene resin, vinyl resin, divinylbenzene resin, polyamide resin, poly Thermoplastic polymers such as ester resins, polycarbonate resins, polyacetal resins, polyethersulfone resins, polyphenyloxide resins, polyphenylene sulfide resins, polysulfone resins, and polyurethane resins. The polymer resin may be synthesized from the core material fine particles by an emulsion polymerization method.

By coating the metal layer 12 on the surface of the polymer core material particles 11, it can serve as a conductor. Specific examples of the metal to be plated include gold, silver, copper, nickel, copper, aluminum, chromium, iron, manganese, and the like, which may be formed of two or more mixed layers of these materials.

The thickness of the metal layer to be plated may be 50 to 150 nm in the case of a single layer, or 100 to 300 nm in the case of a mixed layer of two or more layers, preferably two layers of 100 nm.

As the method of plating the metal layer 12, an electroless plating method can be used. The technique of forming the metal layer using the electroless plating method can be easily carried out by those skilled in the art.

On the other hand, as shown in Figure 2 as another embodiment of the present invention, instead of coating the metal layer on the polymer core material fine particles it is also possible to use the metal core material fine particles (11 ').

Insulation Layer Formation Using Dry Oval Fine Particle Composite Machine

A process of forming an insulating layer on the surface of the metal layer coated fine particles (11, 12) or the metal core material particles (11 ') prepared by the above method is as follows.

FIG. 3 is a schematic cross-sectional view of a dry elliptical particulate composite device for forming an insulating layer of conductive fine particles according to the present invention, FIG. 4 is a schematic cross-sectional view of a cutting plane taken along the line A-A 'of FIG. A cross-sectional view schematically illustrating a process of forming an insulating layer on core material fine particles using a dry elliptical fine particle composite machine used in the present invention.

As shown in Figures 3 and 4, the process of forming the insulating layer of the present invention uses a dry elliptical particulate composite device (2). The dry elliptical fine particle composite machine 2 used in the present invention was conventionally used to modify microparticles used for surface modification for preventing oxidation of metals, and in the present invention, an insulating layer is formed on the outermost layer of the particles. It was introduced to. The dry elliptical particulate composite machine 2 has a small elliptical rotor 2 of the same size in a vessel 21 having an internal space of an elliptic type, and a driving unit (not shown). It operates on the principle of rotating by the shaft 24 received power from the.

Looking at the operation process, the fine particle (or metal particles) coated with a metal layer and the resin fine particles for forming the insulating layer are put together in the inside of the rotating container 21, and the dry elliptical fine particle composite machine 2 is operated. At this time, as shown in Figures 4 and 5, the rotating container 21 and the rotor 22 is rotated in the opposite direction, and the fine particles (or metal particles) coated with a metal layer between the gaps 25 and When the resin fine particles for forming the insulating layer passes, the resin fine particles for forming the insulating layer adhere to the surfaces of the fine particles (or metal particles) coated with the metal layer by the shear force of each other. The surface of the particles is activated by the friction force continuously acting between the particles, and the sintering connection phenomenon occurs between the particles by the mechanical action to produce the conductive fine particles having an insulating layer formed on the outermost layer.

As such, the gap 25 between the rotating container 21 and the rotor 22 is adjusted by using the dry elliptical fine particle composite machine 2, and the rotational speed, the dosage, the metal coating particles (or metal particles) and the insulating layer are formed. By controlling the mixing ratio of the resin fine particles for appropriately, the conductive fine particles can be produced as needed. In this invention, it is preferable to use the speed of the rotating container 21 in the range of 50-250 rpm, and the rotor 22 in the range of 100-5,000 rpm.

Specific examples of the polymer resin used for the resin fine particles for forming the insulating layer include phenol resin, urea resin, melamine resin, fluorine resin, polyester resin, epoxy resin, silicone resin, polyimide resin, polyurethane resin, propylene resin, Thermosetting polymer resins such as polyolefin resins, or polyethylene resins, polypropylene resins, polybutylene resins, polymethacrylic resins, polystyrene resins, acrylonitrile-styrene resins, acrylonitrile-styrene-butadiene resins, vinyl resins, poly And thermoplastic polymers such as amide resins, polyester resins, polycarbonate resins, polyacetal resins, polyethersulfone resins, polyphenyloxide resins, polyphenylene sulfide resins, polysulfone resins and polyurethane resins.

The resin fine particles for forming the insulating layer preferably have a glass transition temperature of 50 to 130 ° C. When having a glass transition temperature of a temperature outside this range, problems such as agglomeration and unevenness of the coating may occur during the insulation treatment. In addition, the resin fine particles for forming the insulating layer used in the production method of the present invention can be appropriately selected in the range of 0.1 to 10 탆 in average particle diameter.

The thickness of the insulating layer 13 formed through the dry elliptic fine particle composite machine 2 is preferably in the range of 200 to 500 nm. Outside of this range, the binding force between the polymer core material and the metal is not affected.

In the conductive fine particles produced according to the method for producing conductive fine particles for anisotropic conductive films of the present invention, since the outermost layer is an insulating layer, it is possible to prevent a short circuit between adjacent terminals, and when collapsed between substrates, z Since it has the property of energizing only in the axial direction, it is suitable for producing an anisotropic conductive film having high insulation reliability and conduction reliability.

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

In the embodiment of the present invention, the spherical polymer core material fine particles made of divinylbenzene resin having a uniform particle size were synthesized by emulsion polymerization. At this time, the particle diameter of the core material fine particles was 5 µm.

Again, the conductive metal layer was formed on the surface of the core material fine particles by using an electroless plating method, and formed of two layers, a nickel layer and a gold layer. At this time, the thickness of the mixed layer of nickel and gold was 100 to 200 mm.

In order to insulate the surface of the metal-coated fine particles thus prepared, according to the composition of Table 1 below, the dry elliptical fine particle composite machine (using θ-composer manufactured by Tokuju, Japan) coated fine particles with a nickel / metal layer and an insulating layer having a particle diameter of 200 nm The polymer resin fine particles for the formation were added 60% of the capacity at a ratio of 5: 1, and then the rotating container was rotated at a rotational speed of 100 rpm and the rotor at a rotational speed of 4,000 rpm for 20 to 30 minutes to form an outermost insulating layer. . The surface of the fine particles thus formed was observed with S.E.M., and the results are shown in FIGS. 6A and 6B.

Next, to prepare an anisotropic conductive film using the prepared microparticles, 65 parts by weight of NBR rubber, 25 parts by weight of bisphenol A type epoxy resin having an epoxy equivalent of 7000, and 4 parts by weight of 2-methylimidazole as a curing agent, toluene and methyl After dissolving in a mixed solvent of ethyl ketone, the prepared conductive fine particles were well dispersed with a silane coupling agent, and then coated and dried on a release PET film to prepare an anisotropic conductive film having a thickness of 27 μm. The number of electroconductive fine particles contained in the film per unit area was 25,000 piece / mm <2>. Using the anisotropic conductive adhesive film thus prepared, insulation evaluation of the IC chip was performed as follows.

The bump height of the evaluation IC chip used was about 40 µm and the size of the IC chip was 6 mm x mm. The board | substrate which formed the wiring pattern by copper and gold plating of 8 micrometer thickness on the board | substrate of 0.8 mm thick BT resin was used. A temperature of 50 ° C. and a pressure of 10 MPa − in the state where the anisotropic conductive adhesive film is described between the IC chip and the substrate (in this case, the sum of the bump height and the wiring pattern height is about 58 μm). It was pressurized for 15 seconds under conditions of a bump, and it crimp | bonded and connected.

The insulation resistance was evaluated by applying a voltage of 50 V to the two adjacent pins of the connection sample thus made for 10 seconds. The results are shown in Table 1. In the case where the insulation resistance was 10 ⁹ kPa or more, the evaluation was evaluated as ,, and in the case of 10 ⁹ kPa or less. In addition, as a method of identifying unreacted core material particles, the degree of conductivity was confirmed by attempting to measure the conductivity of the particles using a compression hardness tester (Micro Compression Testing Machine, manufactured by Shimadzu).

Example 1 Example 2 Example 3 Content of electroconductive fine particles (E.A / mm2) 25,000 30,000 30,000 Kind of insulating resin layer Fluorine Resin Polystyrene resin Polystyrene resin Thickness of outermost insulation layer (nm) 200 300 400 Area of IC Bump Used for Electrical Evaluation (μm ² ) 3,000 3,000 3,000 Insulation evaluation ◎ ◎ ◎ Unreacted Heartwood (%) 2 4 3.5

Comparative Examples 1 to 3

The insulating resin of the outermost layer was carried out under the same conditions as in Examples 1 to 3 except that the insulating resin was formed by a conventional hybridization system.

Comparative Example 1 Comparative Example 2 Comparative Example 3 Content of electroconductive fine particles (E.A / mm2) 25,000 30,000 30,000 Kind of insulating resin layer Fluorine Resin Polystyrene resin Polystyrene resin Thickness of outermost insulation layer (nm) 200 300 400 Area of IC Bump Used for Electrical Evaluation (μm ² ) 3,000 3,000 3,000 Insulation evaluation ◎ ◎ ◎ Unreacted Heartwood (%) 3 5 3

S.E.M. shown in FIGS. 6A and 6B. It can be seen from the photograph that the conductive fine particles produced by the method for producing conductive fine particles for anisotropic conductive films according to the present invention have a relatively uniform insulating layer formed on its surface.

In addition, in the results shown in Table 1 and Table 2, when using the conductive fine particles prepared according to the present invention, because it was treated with a dry elliptical fine particle composite machine, compared with the conventional process, it is low in forming the outermost layer It can be seen that the deposition rate can be increased by electric power.

According to the present invention, since the insulating layer is formed at the outermost part of the core material particles using the dry elliptical fine particle composite machine, the coating film thickness of the insulating layer can be uniformly formed, and the process of forming the insulating layer is treated with the dry oval fine particle composite machine. The solvent removal process in the conventional process is not necessary, and has the effect of providing the manufacturing method of the electroconductive fine particle for anisotropic conductive films which can raise a film-forming rate.

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 (9)

Plating a metal layer on the surface of the particulate polymer core material; Injecting the polymer core material fine particles having a metal layer plated therein and the resin fine particles for forming an insulating layer into the rotary container of the dry elliptic particulate composite machine including a rotor in the rotary container and the rotary container; And Forming the insulating layer by attaching the resin fine particles for forming the insulating layer on the surface of the fine metal plated with the metal layer by rotating the rotating container and the rotor in opposite directions; The manufacturing method of the electroconductive fine particle for anisotropic conductive films which consists of a step. The method of claim 1, wherein the polymer core material fine particles and the resin fine particles for forming the insulating layer is a phenol resin, urea resin, melamine resin, fluorine resin, polyester resin, epoxy resin, silicone resin, polyimide resin, polyurethane resin, Propylene resins, polyolefin resins, polyethylene resins, polypropylene resins, polybutylene resins, polymethacrylic resins, polystyrene resins, acrylonitrile-styrene resins, acrylonitrile-styrene-butadiene resins, vinyl resins, divinylbenzene resins And a material selected from the group consisting of polyamide resins, polyester resins, polycarbonate resins, polyacetal resins, polyethersulfone resins, polyphenyloxide resins, polyphenylene sulfide resins, polysulfone resins, and polyurethane resins. Production of conductive fine particles for anisotropic conductive film, characterized in that . The method for producing conductive fine particles for anisotropic conductive films according to claim 1, wherein the fine polymer core material fine particles and the fine resin particles for forming the insulating layer are spherical fine particles with an average particle diameter of 0.1 to 10 m. The method of manufacturing the conductive fine particles for anisotropic conductive films according to claim 1, wherein the insulating layer is formed of resin fine particles having a glass transition temperature of 50 to 130 ° C, and the thickness of the insulating layer is 200 to 500 nm. . The method of claim 1, wherein the plating of the metal layer on the surface of the polymer core material fine particles uses an electroless plating method. The method of claim 1, wherein the metal layer has a thickness of 50 to 150 nm for a single layer and 100 to 300 nm for a mixed layer of two or more layers. The method for producing conductive fine particles for anisotropic conductive films according to claim 1, wherein the polymer core material fine particles are emulsion emulsion polymerization. Injecting the metal core material fine particles and the resin fine particles for forming the insulating layer into the rotary container of the dry elliptical fine particle composite machine including the rotor in the rotary container and the rotary container; And Rotating the container and the rotor in a direction opposite to each other to attach the resin fine particles for forming the insulating layer on the surface of the metal core material fine particles to form an insulating layer; The manufacturing method of the electroconductive fine particle for anisotropic conductive films which consists of a step. Electroconductive fine particles for anisotropic conductive films manufactured by the manufacturing method of Claim 1 or 8.

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