KR20080100991A - Method for manufacturing anisotropic conductive film - Google Patents

Abstract

A method for manufacturing anisotropic conductive film is able to correspond to the minute connection pitch by uniformly forming conductive particles charged with the same polarity on a base through a static electricity spraying mode in the manufacture of the anisotropic conducting film. A method for manufacturing anisotropic conductive film comprises a step(S100) for spraying the droplet including conductive particles on a base by using a static electricity spraying mode; and a step(S110) for forming a insulating adhesive resin on the base. The step for spraying the droplet including conductive particles comprises a step for supplying the liquid including the conductive particles inside a nozzle of the static electricity spraying equipment arranged on the top of base; a step for authorizing the voltage to the nozzle of the static electricity spraying equipment; and a step for spraying the droplet including the conductive particles on the base.

Description

Method for producing anisotropic conductive film {METHOD FOR MANUFACTURING ANISOTROPIC CONDUCTIVE FILM}

1 is a view for schematically explaining the principle of the electrostatic spray used in the production of the anisotropic conductive film according to an embodiment of the present invention.

2 is a process flowchart for schematically illustrating a manufacturing process of the anisotropic conductive film according to an embodiment of the present invention.

3A to 3C are cross-sectional views illustrating a manufacturing process of an anisotropic conductive film according to an embodiment of the present invention.

{Description of symbols for main parts of the drawing}

200: base material 230b: conductive particles

240: insulating adhesive resin 260: anisotropic conductive film

The present invention relates to a method for producing an anisotropic conductive film.

In general, an anisotropic conductive film (ACF) has a fine pitch of signal wires formed on a substrate, so that bumps of a driving integrated circuit (D-IC) for driving the signal wires are fine. It is a connection material used when bumps cannot be attached to the signal wiring by soldering.

Such an anisotropic conductive film is widely used, for example, as a connection material of a drive integrated circuit for driving a liquid crystal panel and a liquid crystal panel of a liquid crystal display (LCD).

The anisotropic conductive film may be made of an insulating adhesive resin and conductive particles dispersed in the insulating adhesive resin.

A conventional anisotropic conductive film having the above structure is produced by dispersing the conductive particles in the insulating adhesive resin and then die casting the insulating adhesive resin in which the conductive particles are dispersed onto a substrate. .

However, such a conventional method for producing an anisotropic conductive film may be in contact with the conductive particles when the dispersion of the conductive particles is not good.

For this reason, a problem may occur in which a short circuit occurs in the transverse direction of the connection, that is, in the plane direction of the anisotropic conductive film.

For this reason, there are many difficulties in responding to a fine connection pitch with the conventional anisotropic conductive film.

Therefore, the technical problem to be achieved by the present invention is to provide a method for producing an anisotropic conductive film that can cope with fine connection pitch.

Further technical problems to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above are clearly understood by those skilled in the art from the following description. Can be understood.

Method for producing an anisotropic conductive film according to an embodiment of the present invention for achieving the above technical problem is spraying a droplet containing conductive particles on a substrate by using an electrostatic spray (electrostatic spray) method; And forming an insulating adhesive resin on the substrate.

Specific details of other embodiments are included in the detailed description and the drawings. Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings.

Hereinafter, a method of manufacturing an anisotropic conductive film according to an embodiment of the present invention with reference to the accompanying drawings will be described in detail.

An anisotropic conductive film according to an embodiment of the present invention can be prepared by spraying a droplet containing conductive particles on a substrate using an electrostatic spray method, and then forming an insulating adhesive resin on the substrate. .

Prior to describing a method of manufacturing an anisotropic conductive film according to an embodiment of the present invention in detail, the principle of the electrostatic spraying will be described with reference to FIG. 1.

1 is a view for schematically explaining the principle of the electrostatic spray used in the production of the anisotropic conductive film according to an embodiment of the present invention.

Referring to FIG. 1, electrostatic spraying refers to dispersing the liquid 120 supplied into the nozzle 100 into a small droplet 130 using purely electric force, for example.

That is, after the liquid 120 is split into droplets 130 having the corresponding polar ions according to the polarity voltage applied to the nozzle 110 of the fine capillary shape in the electrostatic spraying equipment using the electrostatic spraying, the droplets 130 It may be sprayed onto the substrate 100.

Specifically, for example, when the voltage of the anode is applied to the nozzle 110 so that the nozzle 110 acts as an anode, the anion that has been dissolved in the liquid 120 introduced into the nozzle 110 may become the nozzle 110. In addition to implantation or migration to the wall surface of the c), the remaining cations can be pushed to the meniscus.

At this time, as the voltage of the anode applied to the nozzle 110 increases, the repulsive force of the electric force and the cation acting on the liquid curved surface becomes larger than the surface tension of the liquid 120, so that the liquid curved surface at the end of the nozzle 110 is increased. It forms the shape, which is called the cone-jet mode. Here, the liquid curved surface is a cone cone (liquid cone 122), the liquid jet 122 is a liquid jet (124) is formed by the surface shear stress (surface tangential stress) at the end.

The liquid column 124 is broken into droplets 130 having a predetermined size, for example, a size of several tens of nanometers to several tens of micrometers by disturbance of surface waves acting on the surface of the liquid column 124 at the end of the liquid column 124. Broken droplets 130 may be sprayed onto the substrate 100.

As such, the droplets 130 sprayed onto the substrate 100 through electrostatic spray not only have a monodisperse distribution but also the droplets 130 are well-charged because the surfaces of the droplets 130 are charged with the same polarity. The advantage is that it does not aggregate.

On the other hand, Figure 2 is a process flow diagram for schematically illustrating a manufacturing process of the anisotropic conductive film according to an embodiment of the present invention. 3A to 3C are cross-sectional views illustrating a manufacturing process of an anisotropic conductive film according to an embodiment of the present invention.

In order to manufacture the anisotropic conductive film according to an embodiment of the present invention, first, as shown in Figure 2, by using the above-described electrostatic spray method spraying a droplet containing conductive particles on the substrate (S100).

Specifically, first, as shown in FIG. 3A, the substrate 200 is seated on a roll 202.

The substrate 200 may be formed of, for example, a polyethylene terephthalate material to have a predetermined thickness, for example, a thickness of several tens of μm. At least one surface of the substrate 200 may be surface treated. This is to facilitate the peeling of the substrate 200 when the anisotropic conductive film is used as the connecting material.

The roll 202 may rotate in one direction so that the droplets 230a including conductive particles may be evenly sprayed onto the substrate 200. The roll 202 may be formed of a metal material so that a predetermined voltage, for example, a ground voltage or a voltage of a negative electrode may be applied thereto.

Subsequently, the liquid 220 including the conductive particles is supplied into the nozzle 210 of the electrostatic spraying equipment disposed on the substrate 200.

The nozzle 210 of the electrostatic spray equipment is formed in a fine capillary shape, and the inner diameter of the nozzle 210 may be, for example, several μm to thousands μm, but is not limited thereto.

The liquid 220 supplied into the nozzle 210 may specifically include the conductive particles and the organic solvent.

The conductive particles included in the liquid 220 supplied into the nozzle 210 include aluminum (Al), copper (Cu), silver (Ag), gold (Au), platinum (Pt), nickel (Ni), and titanium. It may include a conductive layer consisting of one or more selected from the group consisting of (Ti), it may be composed of a single layer to multiple layers.

For example, the conductive particles may be particles consisting of only the conductive layer, that is, a single layer. Alternatively, the conductive particles may be particles in which the conductive layer is coated on a spherical nucleus such as polystyrene, that is, a double layer. Alternatively, the conductive particles may be particles in which the conductive layer is coated on a spherical nucleus such as polystyrene, and an insulating layer is coated on the conductive layer, that is, a triple layer.

As such, the conductive particles included in the liquid 220 supplied into the nozzle 210 only need to include the conductive layer, and thus there is no particular limitation in the specific form.

As an organic solvent included in the liquid 220 supplied into the nozzle 210, the organic solvent having polarity and easily volatilized at room temperature, for example, ethanol, may be easily used even at a low temperature. ) Only the conductive particles can be left.

Subsequently, a voltage is applied to the nozzle 210 of the electrostatic spray equipment.

Specifically, for example, the voltage of the anode is applied to the nozzle 210 so that the nozzle 210 acts as an anode. Meanwhile, a predetermined voltage, for example, a ground voltage or a voltage of a negative electrode may be applied to the roll 202, but is not limited thereto.

When the voltage of the anode is applied to the nozzle 210, as the voltage of the anode applied to the nozzle 210 increases, the liquid column 224 may be formed at the end of the liquid cone 222.

At this time, the liquid column 224 is broken into droplets 230a containing conductive particles by the disturbance of the surface wave acting on the surface of the liquid column 224 at the end of the liquid column 224, the broken droplet 230a is the substrate 200 May be sprayed on.

The droplets 230a including conductive particles sprayed onto the substrate 200 may not aggregate with each other because the droplets 230a are charged with the same polarity.

Subsequently, the organic solvent included in the droplet 230a may be removed by drying the substrate 200 under a predetermined temperature. By such a drying process, only conductive particles that are charged with the same polarity on the substrate 200 and do not aggregate with each other may remain. However, the drying process may be omitted in some cases.

Next, as shown in Figure 2, by spraying a droplet containing conductive particles on a substrate using an electrostatic spray method (S100), to form an insulating adhesive resin on the substrate (S110).

Specifically, first, as shown in FIG. 3B, the insulating adhesive resin 240 is filled in the inkjet equipment 250. Subsequently, the head 252 of the inkjet equipment 250 is moved in one direction to drop the insulating adhesive resin 240 temporarily filled in the head 252 onto the front surface of the substrate 200 through the nozzle 254. As a result, the conductive particles 230b formed on the substrate 200 may be covered by the insulating adhesive resin 240. On the other hand, the formation of the insulating adhesive resin 240 is not limited to the above. For example, the insulating adhesive resin 240 may be formed on the substrate 200 using a die casting method.

The insulating adhesive resin 240 may include a thermosetting resin, a curing agent for a thermosetting resin, and an organic solvent. In addition, the insulating adhesive resin 240 may further include a thermoplastic resin and other additives.

As the thermosetting resin contained in the insulating adhesive resin 240, for example, an epoxy resin can be used. Examples of the epoxy resin include bisphenol-type epoxy resins derived from epichlorohydrin and bisphenols A, F and AD, and epoxy novolac resins and naphthalene rings derived from epichlorohydrin and phenol novolac or cresol novolac. Naphthalene-based epoxy resins having a skeleton, glycidylamine, glycidyl ether, biphenyl, various epoxy compounds having two or more glycidyl groups in one molecule such as alicyclic, etc. alone or in combination of two or more Can be used.

Such a thermosetting resin has the characteristic that the melt viscosity is relatively quick in the initial stage of connection of an anisotropic conductive film compared with a thermoplastic resin.

Therefore, when the thermosetting resin is used as the insulating adhesive resin 240, since the exclusion property of the insulating adhesive resin 240 is excellent between the conductive particles 230b and the connected object, high conductive properties can be obtained.

As the curing agent for thermosetting resin contained in the insulating adhesive resin 240, for example, a curing agent for epoxy resin may be used. In addition, as a curing agent for thermosetting resins, imidazole series, hydrazide series, boron trifluoride-amine complex, sulfonium salt, amineimide, salt of polyamine, dicyandiamide and the like can be used.

As the thermoplastic resin included in the insulating adhesive resin 240, a phenoxy resin, a polyester resin, a polyamide resin, or the like may be used.

Such a thermoplastic resin is effective in alleviating the stress generated during the curing of the thermosetting resin.

An aromatic hydrocarbon may be used as the organic solvent included in the insulating adhesive resin 240.

Meanwhile, after the insulating adhesive resin 240 is formed on the substrate 200 (S110), the substrate 200 is hot-air dried at a predetermined temperature, for example, 70 ° C. for a predetermined time, for example, 10 minutes. 3C, an anisotropic conductive film 260 made of conductive particles 230b and an insulating adhesive resin 240 may be manufactured on the substrate 200.

As described above, since the conductive particles charged with the same polarity can be formed on the substrate by the electrostatic spray method through the method of manufacturing the anisotropic conductive film according to an embodiment of the present invention, the surface direction of the anisotropic conductive film As a result, a short circuit may occur.

For this reason, the anisotropic conductive film manufactured according to one embodiment of the present invention may correspond to the fine connection pitch.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains can realize that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. I can understand that.

Therefore, since the embodiments described above are provided to completely inform the scope of the invention to those skilled in the art, it should be understood that they are exemplary in all respects and not limited. The invention is only defined by the scope of the claims.

According to the present invention, since the conductive particles charged with the same polarity can be uniformly formed on the substrate by using the electrostatic spray method during the production of the anisotropic conductive film, an anisotropic conductive film can be produced that can cope with the fine connection pitch.

Claims (7)

Spraying droplets containing conductive particles onto the substrate using an electrostatic spray method; And Forming an insulating adhesive resin on the substrate Method for producing an anisotropic conductive film comprising a. The method of claim 1, wherein spraying the droplets containing the conductive particles, Supplying a liquid comprising the conductive particles into a nozzle of an electrostatic spraying equipment disposed on top of the substrate; Applying a voltage to the nozzle of the electrostatic spraying equipment; And Spraying a droplet comprising the conductive particles on the substrate; Method for producing an anisotropic conductive film comprising a. The method of claim 1, The conductive particles are at least one conductive layer selected from the group consisting of aluminum (Al), copper (Cu), silver (Ag), gold (Au), platinum (Pt), nickel (Ni) and titanium (Ti). Method for producing an anisotropic conductive film comprising a. The method of claim 1, The insulating adhesive resin is a curing agent for thermosetting resins and thermosetting resins Method for producing an anisotropic conductive film comprising a. The method of claim 4, wherein The said thermosetting resin is an epoxy resin, The said hardening | curing agent for thermosetting resins is a hardening | curing agent for epoxy resins, The manufacturing method of the anisotropic conductive film characterized by the above-mentioned. The method of claim 1, Forming the insulating adhesive resin is using the inkjet method Method for producing an anisotropic conductive film comprising a. The method of claim 1, Forming the insulating adhesive resin is a step of using a die casting (die casting) method Method for producing an anisotropic conductive film comprising a.

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