KR20100010694A - Triple layered anistropic conductive film and manufacturing method thereof - Google Patents

Abstract

PURPOSE: A three-layered anisotropic conductive film and a manufacturing method thereof are provided to offer good insulating property without conductivity in an X-shaft and a Y-axis, and to improve adhesion property of an anisotropic conductive film. CONSTITUTION: A three-layered anisotropic conductive film comprises an ACF layer including conductive balls(4) processed with insulating property and an insulating adhesive and an NCF layer(1) including the insulating adhesive and nanosilica(2). The insulating adhesive on the ACF layer and the NCF layer includes one or more component selected from a group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy, novolak type epoxy resin, phenol resin, urea resin, melamine resin, unsaturated polyester resin, resorcinol resin, saturated polyester resin, vinyl resin, acrylic resin, polyolefin resin, polyvinylacetate(PVA) resin, polycarbonate resin, cellulosic resin, ketone resin, and styrene resin.

Description

Triple layered anistropic conductive film and manufacturing method

The present invention relates to a three-layer anisotropic conductive film and a method for manufacturing the same, in particular 1) an ACF layer comprising an insulating adhesive and an insulated conductive ball, and 2) an insulating adhesive formed on both sides of the ACF layer, and The present invention relates to a three-layer anisotropic conductive film composed of an NCF layer containing nano silica and a method of manufacturing the same.

As the technology of electric, electronic, and information communication develops, the necessity of electronic products with smaller and more diverse functions is increasing. This requires a manufacturing technology that can assemble complex and diverse parts small and efficiently. This is called packaging technology. Packaging technology is a technology that enables the economic production of light, thin, short, and fired electronic products in a very small space and allows for more efficient use for a long time. Production technology. In other words, more functions can be implemented more economically while maintaining better reliability in a smaller space.

In recent years, as the display industry becomes larger and thinner, the pitch between electrodes and circuits is gradually becoming smaller, and as one of the wiring mechanisms for connecting these fine circuit terminals, an anisotropic conductive film (ACF) is very It plays an important role.

The anisotropic conductive film is a connection material used when the material of the member to be connected is special or the pitch of the signal wiring is minute so that the member and the member cannot be attached by soldering. The anisotropic conductive film is typically used as a connection material for packaging LCD panels, printed circuit boards (PCBs), driver IC circuits, etc. in LCD modules. More specifically, a plurality of driver ICs are mounted to drive thin film transistor (TFT) patterns in the LCD module. The driver IC is mounted on the LCD panel using a wire bonding method, which connects the driver IC to the LCD panel electrode through a conductive wire, and a TAB (tape automated) method of mounting the driver IC on an electrode on the LCD panel using a base film. and a chip on glass (COG) method in which a driver IC is directly mounted on an LCD panel using a bonding method and a predetermined adhesive. That is, the anisotropic conductive film has attracted attention as a connection material such as COG mounting or chip on film (COF) mounting, and an interconnection pattern designed on a polyimide substrate and an ITO pattern formed on a glass substrate of a liquid crystal display device or It is used to electrically connect the lead of an electronic component or the like.

Recently, in the circuit board packaging required for such anisotropic conductive connection, the number of leads printed on the substrate increases as the connection pitch becomes finer and the IC bump becomes smaller according to the development of circuit and LCD technology. Being. In accordance with such technical requirements, research and development are continuing to reduce the particle size of the conductive fine particles contained in the anisotropic conductive adhesive film and to increase the amount of the conductive fine particles to improve the connection reliability. However, agglomeration or bridging of particles occurs due to reduced particle size and increased particle density of the conductive fine particles used, resulting in frequent nonuniformity of connection or short circuit between patterns.

Anisotropic conductive films have been manufactured by Hitachi Chemical Co., Ltd. (Japanese Patent Publication Nos. 5-21094, 5-226020, 7-3026666, etc.) and Sony Chemical Corporation (Japanese Patent Publications No. 7-211374, 9-199206, 9-115335, etc.) for the past 10 years. Many researches and commercializations have been conducted. However, the problem of frequent occurrence of non-uniformity of connection or short circuit between patterns has not been completely solved yet, and thus, many improvements in LCD processes are required.

Therefore, there is a need for an anisotropic conductive film that solves the above problems and improves adhesiveness and insulation property compared to existing anisotropic conductive films.

While studying the anisotropic conductive film with improved adhesion and insulation, the present inventors added nano silica as a filler to the NCF layer to prepare an NCF layer, which was formed on both sides of the ACF layer including an insulating adhesive and an insulated conductive ball. The three-layer anisotropic conductive film was prepared by forming each, and it was confirmed that the adhesive strength, the conduction reliability, and the insulation reliability of the anisotropic conductive film were excellent, and completed the present invention.

The present invention is to provide a three-layer anisotropic conductive film excellent in adhesion and insulation and a method of manufacturing the same.

The present invention

1) an ACF layer comprising an insulating adhesive and an insulated conductive ball, and

2) Provide a three-layer anisotropic conductive film consisting of an NCF layer containing an insulating adhesive and nano silica, respectively formed on both sides of the ACF layer.

In addition, the present invention

1) mixing the nano silica dispersed in the organic solvent to the insulating adhesive, and then applying it on the base film and dried to produce an NCF film,

2) mixing the insulated conductive balls dispersed in an organic solvent with an insulating adhesive, and then applying it on a base film and drying to prepare an ACF film,

3) It provides a method of manufacturing a three-layer anisotropic conductive film comprising the step of adhering the NCF film prepared in step 1) to both sides of the ACF film prepared in step 2) through a lamination process.

Hereinafter, the present invention will be described in detail.

In the ACF layer and the NCF layer of the three-layer anisotropic conductive film according to the present invention, the insulating adhesive includes at least one resin selected from thermosetting resins and thermoplastic resins. The thermosetting resins include, but are not limited to, bisphenol A type epoxy resins, bisphenol F type epoxy resins, noblock type epoxy resins, phenol resins, urea resins, melamine resins, unsaturated polyester resins, resorcinol resins, and the like. The thermoplastic resins include, but are not limited to, saturated polyester resins, vinyl resins, acrylic resins, polyolefin resins, polyvinyl acetate (PVA) resins, polycarbonate resins, cellulose resins, ketone resins, styrene resins, and the like. In this invention, it is preferable to use a thermosetting resin.

In the ACF layer of the three-layered anisotropic conductive film according to the present invention, the insulated conductive ball has an insulating property on the surface of the conductive particle by using an insulating method of inducing an organic polymer compound of particles of several hundred nanometers in size to the surface of the conductive particle. Grant. In the insulating method, the entire surface of the conductive particles is not thin-film-coated with an organic insulating film, and only a portion of the conductive particles is uniformly insulated with the organic polymer guest particles, whereby the portion which comes into contact with the electrode in the heat compression process is an organic polymer. As the guest particles are pushed out to have conductivity, they have both insulating and conductive properties. In the insulated conductive ball, the conductive particles include metal particles such as nickel, gold, platinum, and copper, and the insulating particles are styrene, styrene crosslinked fine particles, acrylic, acrylic crosslinked fine particles, styreneacryl copolymer or styreneacryl crosslinked fine particles. At least one selected from the group consisting of, preferably at least one selected from the group consisting of styrene, acrylic and styrene acrylic copolymer. The insulating particles may be prepared through a suspension polymerization reaction by mixing a monomer composition, a chain extender, a polymerization initiator, a viscosity lowering agent, a dispersion stabilizer, or the like through mechanical or physical methods. The size of the insulating conductive ball is 1 ~ 10㎛, preferably 2 ~ 5㎛. The content of the insulated conductive balls may be dispersed in an amount of 1 to 30 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the ACF layer. If the content of the insulated conductive ball is more than 30 parts by weight, the insulation reliability between the connection circuits is difficult to be secured, and thus anisotropic conductivity is not exhibited.

In the NCF layer of the three-layer anisotropic conductive film according to the present invention, nano silica is used as a filler, and serves to improve the adhesion and insulation of the anisotropic conductive film. The particle size of the nano silica is preferably circular silica having 6 to 30 nm. The content of the nano silica is preferably 0.1 to 30 parts by weight, preferably 0.5 to 5 parts by weight based on 100 parts by weight of the NCF layer. In the present invention, a commercial product of Fuso Chemical Company was used.

The total thickness of the three-layer anisotropic conductive film according to the present invention is preferably 15 to 30 µm, and the thickness of the NCF layer and ACF layer is preferably 5 to 10 µm, respectively.

The three-layer anisotropic conductive film according to the present invention is produced by the following method.

First, a curing agent is added to at least one resin selected from a thermosetting resin and a thermoplastic resin to prepare an insulating adhesive. It is preferable that the said resin contains 80-90 weight part with respect to 100 weight part of insulating adhesives. The said hardening | curing agent can use the compound which is inert at normal temperature, and activates after heat melting and hardening a thermosetting resin. Such curing agents include, but are not limited to, one or more selected from the group consisting of imidazole compounds, amine compounds, acid anhydride compounds, polyamide compounds, and isocyanate compounds, and in the present invention, microencapsulate the compound. Use a commercially available product. It is preferable that the said hardening | curing agent contains 1-10 weight part with respect to 100 weight part of insulating adhesives. The insulating adhesive may further include additives such as a surfactant and a coupling agent in addition to the resin and the curing agent.

Then, after dispersing the nano silica in an organic solvent, it is added to the prepared insulating adhesive and mixed. The mixed solution containing the nano silica is applied onto a base film and dried to prepare an NCF film. Then, the insulating conductive ball is dispersed in an organic solvent and then mixed with the insulating adhesive prepared above. An ACF film is prepared by applying a mixed solution including the electrically conductive balls insulated and then drying the base film. The NCF film prepared above is attached to one side of the prepared ACF film through a lamination process, and then the NCF film prepared above is bonded to the other side of the ACF film through a lamination process to prepare a three-layer anisotropic conductive film.

The organic solvent is to lower the viscosity of the anisotropic conductive film to facilitate the film production, consisting of toluene, xylene, ethyl acetate, benzene, acetone, methyl ethyl ketone, tetrahydrofuran, dimethylformaldehyde and cyclohexanone One or more selected from the group include, but are not limited to, any organic solvent typically used in the production of an anisotropic conductive film can be used. Since the content of the organic solvent in the present invention is added in an appropriate amount for controlling the viscosity, it is not particularly limited, and preferably adjusted to 5 to 70 parts by weight.

When the three-layer anisotropic conductive film according to the present invention is pressed for 6 to 10 seconds at a pressure of 3 to 5Mpa at 180 to 200 ° C, the adhesive strength is excellent as 15N / cm or more, and the adhesive strength is maintained even after 1000 hours in constant temperature and humidity. It is excellent in keeping 10N / cm or more. In addition, the three-layer anisotropic conductive film according to the present invention is excellent in conduction reliability and insulation reliability. As described above, the three-layer anisotropic conductive film according to the present invention exhibits excellent adhesive strength by adding nano-silica as a filler to the NCF layer, and the nano-silica of the NCF layer maximizes the insulated conductive ball of the ACF layer on the bumps. By allowing it to go up a lot, it is excellent in conduction reliability and insulation reliability.

Therefore, the three-layer anisotropic conductive film according to the present invention is used as an adhesive for a liquid crystal display substrate or the like and is conductive only in the pressing direction due to heating pressure when the circuit is connected, and has excellent conductivity without being conductive in the X and Y axis directions. Has

Hereinafter, preferred examples are provided to aid in understanding the present invention. However, the following examples are merely provided to more easily understand the present invention, and the contents of the present invention are not limited by the examples.

Example  One  : 3rd Floor Anisotropy  Manufacture of conductive film

One. NCF  Manufacture of film

40 parts by weight of phenoxy resin YP-50 (Todo Chemical), 40 parts by weight of epoxy resin Ebicote 630 (DIESEL Chemical Co., Ltd.), 5 parts by weight of a latent curing agent HX3741 (Asahi Hwaseong), were mixed at 1500 to 2000 rpm. Stirred. After removing bubbles generated during stirring, an insulating adhesive was prepared. 5 parts by weight of 10 nm nano silica (fuso chemicla, Japan) was added to 100 ml of toluene and dispersed as a filler. Nano silica dispersed in the toluene was added to the prepared insulating adhesive and mixed with stirring at 1500 to 2000 rpm. The mixed solution containing the nano-silica was applied to a polyester (PET) film using a comma coater and hot air dried by passing through three zones of 60 ~ 80 ℃ for 6 minutes. At this time, the tension of the coating machine was set to 25N, the line speed was set to 2.0m / s. In this way, a 10 μm thick NCF film was prepared.

2. ACF  Manufacture of film

40 parts by weight of phenoxy resin YP-50 (Todo Chemical), 40 parts by weight of epoxy resin Ebicote 630 (DIESEL Chemical Co., Ltd.), 5 parts by weight of a latent curing agent HX3741 (Asahi Hwaseong), were mixed at 1500 to 2000 rpm. Stirred. After removing bubbles generated during stirring, an insulating adhesive was prepared. An insulated conductive ball was prepared by coating 4 μm of nickel-gold plated particles (AUL-704, Sekisui Co., Ltd.) on a styrene resin using a hybridizer NHS-0. At this time, the size of the insulating conductive ball was 4.5㎛. The insulating conductive ball was added to 50 ml of toluene and dispersed. The insulated conductive balls dispersed in the toluene were added to the prepared insulating adhesive and mixed with stirring at 1500 to 2000 rpm. The mixed solution containing the insulated conductive balls was applied to a polyester (PET) film using a comma coater, and dried by hot air drying through three zones of 60 to 80 ° C. for 6 minutes. At this time, the tension of the coating machine was set to 25N, the line speed was set to 2.0m / s. In this way, an ACF film having a thickness of 10 μm was prepared.

3. 3rd floor Anisotropy  Manufacture of conductive film

The NCF film prepared in 1 was adhered to one side of the ACF film prepared in 2 through a lamination process. The NCF film prepared in 1 above was then bonded to the other side of the ACF film through a lamination process. In this way, a three-layer anisotropic conductive film having a thickness of 30 µm was prepared. In the prepared three-layer anisotropic conductive film, the dispersion degree of the ACF layer was photographed through an optical microscope and a program, and the particle area ratio of the surface-treated conductive balls was 50 ± 5%.

Comparative example  One  :

In Example 1, a three-layer anisotropic conductive film was prepared in the same manner as in Example 1 except that the NCF film was prepared without adding nano silica when the NCF film was prepared.

Experimental Example  One  : Adhesion Strength Evaluation

In order to evaluate the adhesive strength of the three-layer anisotropic conductive film according to the present invention, the following experiment was performed.

After pressing the three-layer anisotropic conductive film prepared in Example 1 and Comparative Example 1 between the flexible printed circuit board (FPCB, pitch 200㎛) and the ITO glass substrate, using a bonder (Buseongsa, Korea) A specimen was prepared by pressing at 180 ° C. for 3 seconds at a pressure of 3 Mpa. Adhesive strength was measured by the 90 ° adhesive strength method using Tensilon (AND, Japan). The tensile speed was performed at 50 mm / minute.

In addition, in order to evaluate the adhesive strength after 1000 hours left in constant temperature and humidity, the prepared specimens were measured in the same manner after 1000 hours standing at 85 ℃, 85% RH conditions.

The results are shown in Table 1.

Example 1 Comparative Example 1 Adhesive strength (N / cm) 15 10 Adhesion strength after 1000 hours in constant temperature and humidity (N / cm) 10 6

As shown in Table 1, the three-layer anisotropic conductive film according to the present invention showed an excellent adhesive strength of 15 N / ㎝ or more compared to Comparative Example 1 without the addition of nano silica to the NCF layer, 1000 hours in constant temperature and humidity The adhesive strength after standing was maintained at 10 N / cm or more. As mentioned above, it is judged that the three-layer anisotropic conductive film which concerns on this invention shows the outstanding adhesive strength by adding nano silica as a filler to a NCF layer.

Experimental Example  2  : Conductivity and Insulation Reliability Evaluation

When the adhesive strength was evaluated, the conduction reliability was measured by applying a multimeter (Advantest, Japan) at several mA between the electrodes of the prepared specimen, and the insulation reliability was measured by applying a high resistance meter (Advantest, Japan) at 100V.

The results are shown in Table 2.

Example 1 Comparative Example 1 Continuity reliability ◎ ○ Insulation reliability ◎ ○

※ ◎: Excellent, ○: Normal

As shown in Table 2, the three-layer anisotropic conductive film according to the present invention showed superior conduction reliability and insulation reliability compared to Comparative Example 1 in which nano silica was not added to the NCF layer. As described above, the three-layer anisotropic conductive film according to the present invention is judged to exhibit excellent conduction reliability and insulation reliability by allowing the nano-silica of the NCF layer to rise as much as possible on the bumps the conductive ball of the ACF layer. .

The three-layer anisotropic conductive film according to the present invention exhibits excellent adhesive strength by adding nano silica as a filler to the NCF layer, and allows the nano silica of the NCF layer to rise as much as possible on the bumps of the conductive balls of the ACF layer. It shows excellent conduction reliability and insulation reliability. Therefore, the three-layer anisotropic conductive film according to the present invention is used as an adhesive for a liquid crystal display substrate and the like, and is conductive only in the pressing direction by heating and pressing in a circuit connection, and excellent in the X and Y axis directions. It has insulation.

1 is a view showing a cross section of a three-layer anisotropic conductive film according to the present invention.

2 is a cross-sectional view of the three-layer anisotropic conductive film according to the present invention after the pressure bonding between the flexible printed circuit board (FPCB) and the ITO glass substrate and then bonded.

3 is a view showing a manufacturing process of the ACF film and NCF film in the three-layer anisotropic conductive film according to the present invention.

4 is a view showing a lamination process of the ACF film and NCF film in the production of a three-layer anisotropic conductive film according to the present invention.

Claims (11)

1) an ACF layer comprising an insulating adhesive and an insulated conductive ball, and 2) A three layer anisotropic conductive film composed of an NCF layer comprising an insulating adhesive and nano silica, respectively formed on both sides of the ACF layer. The method of claim 1, wherein the insulating adhesive in the ACF layer and the NCF layer is bisphenol A type epoxy resin, bisphenol F type epoxy resin, noblock type epoxy resin, phenol resin, urea resin, melamine resin, unsaturated polyester resin, resorcinol At least one selected from the group consisting of resins, saturated polyester resins, vinyl resins, acrylic resins, polyolefin resins, polyvinyl acetate (PVA) resins, polycarbonate resins, cellulose resins, ketone resins and styrene resins. Three-layer anisotropic conductive film to make. The method of claim 1, wherein the conductive particles in the conductive ball of the ACF layer comprises at least one metal particle selected from the group consisting of nickel, gold, platinum and copper, the insulating particles are styrene, styrene crosslinked fine particles, acrylic And at least one member selected from the group consisting of acrylic crosslinked fine particles, styreneacryl copolymers or styreneacryl crosslinked fine particles. The three-layer anisotropic conductive film according to claim 1, wherein the conductive ball insulated from the ACF layer has a size of 1 to 10 µm. The three-layer anisotropic conductive film of claim 1, wherein the particle size of the nano silica in the NCF layer is 6 ~ 30nm. The three-layer anisotropic conductive film of claim 1, wherein the nano silica in the NCF layer comprises 0.1-30 parts by weight based on 100 parts by weight of the NCF layer. The three-layer anisotropic conductive film according to claim 1, wherein the total thickness of the three-layer anisotropic conductive film is 15 to 30 µm. The three-layer anisotropic conductive film according to claim 1, wherein the NCF layer has a thickness of 5 to 10 µm. The three-layer anisotropic conductive film according to claim 1, wherein the ACF layer has a thickness of 5 to 10 µm. 1) mixing the nano silica dispersed in the organic solvent to the insulating adhesive, and then applying it on the base film and dried to produce an NCF film, 2) mixing the insulated conductive balls dispersed in an organic solvent with an insulating adhesive, and then applying it on a base film and drying to prepare an ACF film, 3) adhering the NCF film prepared in step 1) to both sides of the ACF film prepared in step 2) through a lamination process. The organic solvent of claim 10, wherein the organic solvent comprises at least one selected from the group consisting of toluene, xylene, ethyl acetate, benzene, acetone, methyl ethyl ketone, tetrahydrofuran, dimethylformaldehyde, and cyclohexanone. The manufacturing method of the three-layer anisotropic conductive film of Claim 1.

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