TWI622635B - Anisotropic conductive film and connecting structure using the same - Google Patents

Abstract

The invention provides an anisotropic conductive film and a connecting knot comprising the same Structure. The anisotropic conductive film comprises: a conductive layer and a dielectric layer each comprising two inorganic fillers having different particle diameters, wherein the dielectric layer has a higher expansion length increase rate than the conductive layer, such as by an equation 1 calculated, and the anisotropic conductive film has a storage modulus of about 2.5 GPa to about 5 GPa, as measured at a curing rate of 90% or higher.

<Equation 1> Expansion length increase rate (%) = {(lateral length of the target layer after main compression - lateral length of the target layer before preliminary compression) / lateral length of the target layer before preliminary compression} ×100

Description

Anisotropic conductive film and conductive structure using same

The present invention relates to an anisotropic conductive film and a connection structure using the same.

In general, an anisotropic conductive film (ACF) refers to a film type adhesive prepared by dispersing conductive particles in a resin such as an epoxy resin, and exhibits conductive properties in the thickness direction of the film and An anisotropic adhesive polymer film exhibiting insulating properties in the surface direction is formed. When the anisotropic conductive film disposed between the circuit boards to be connected is subjected to heating/compression under specific conditions, the circuit terminals of the circuit board are electrically connected to each other via the conductive particles, and the insulating adhesive resin fills between the adjacent electrodes The space isolates the conductive particles from each other, thereby providing high insulation performance.

For a typical two-layer anisotropic conductive film, when the terminals are connected to each other via heating/compression, the film composition containing the conductive particles flows due to heat and pressure, thereby causing the effect of the particles for providing the connection between the terminals. A rather significant reduction. Further, when the composition containing the conductive particles partially flows into the adjacent space (space portion), the conductive particles are concentrated in the small region, thereby causing a short circuit or an increase in contact resistance.

Therefore, there is a need for an anisotropic conductive film which can fill a space between terminals having an insulating adhesive resin while preventing a short circuit between the terminals and exhibiting excellent connection characteristics.

An aspect of the present invention is to provide an anisotropic conductive film in which the dispersibility of conductive particles is improved, thereby exhibiting excellent characteristics in terms of insulation efficiency and connection reliability.

According to an aspect of the present invention, an anisotropic conductive film is provided, comprising: a conductive layer, a dielectric layer, and two inorganic fillers having different particle diameters, wherein the dielectric layer has a conductive layer a high expansion length increase rate, as calculated by Equation 1, and the anisotropic conductive film has a storage modulus of about 2.5 GPa to about 5 GPa, such as a cure rate of 90% or higher. Measure. <Equation 1> Expansion length increase rate (%) = {(lateral length of the target layer after main compression - lateral length of the target layer before preliminary compression) / lateral length of the target layer before preliminary compression} ×100

In accordance with an embodiment of the present invention, the dielectric layer has a rate of expansion length increase of 60% to 120%, and the conductive layer has a rate of expansion length increase of 10% to 60%.

According to an embodiment of the invention, the difference between the rate of increase of the opening length of the conductive layer and the rate of increase of the expanded length of the dielectric layer ranges from 40% to 80%.

According to an embodiment of the invention, the anisotropic conductive film has a particle capture ratio of about 20% to about 60%, as calculated by Equation 2: <Equation 2> Particle capture rate (%) = (in per unit area of the connection region after the main compression (mm ²⁾ number of conductive particles / per unit area of the anisotropic conductive film before preliminary compression (mm ²⁾ number of conductive particles) × 100, wherein 50 The preliminary compression is performed for 1 to 3 seconds at a temperature of from ° C to 80 ° C and a pressure of from 1.0 MPa to 3.0 MPa, and main compression is performed for 3 to 6 seconds at a temperature of from 120 ° C to 160 ° C and a pressure of from 60 MPa to 90 MPa.

According to an embodiment of the present invention, the anisotropic conductive film has a connection resistance of 5 Ω or less after the reliability test, such as a preliminary compression at a temperature of 50 ° C to 80 ° C and a pressure of 1.0 MPa to 3.0 MPa. Main compression for 3 to 6 seconds at a temperature of 3 seconds and 120 ° C to 160 ° C and a pressure of 60 MPa to 90 MPa and then allowing the anisotropic conductive film to stand at 85 ° C and 85% RH for 500 hours Measured.

According to an embodiment of the present invention, the anisotropic conductive film has a minimum melt viscosity of 1,000 to 100,000 Pa•s, as measured at a temperature of 50 ° C to 100 ° C.

According to an embodiment of the present invention, the anisotropic conductive film has an initial occurrence rate of short circuit of 0%, such as a temperature of 50 ° C to 80 ° C and a preliminary compression of 1 to 3 seconds at a pressure of 1.0 MPa to 3.0 MPa and at 120 Measured after 1 to 5 seconds of main compression at a temperature of °C to 160 °C and a pressure of 60 MPa to 90 MPa.

According to an embodiment of the present invention, the anisotropic conductive film has a 0% short-circuit occurrence rate after the reliability test, such as a preliminary compression of 1 to 3 at a temperature of 50 ° C to 80 ° C and a pressure of 1.0 MPa to 3.0 MPa. The primary compression was carried out for 1 to 5 seconds at a temperature of 120 ° C to 160 ° C and a pressure of 60 MPa to 90 MPa and then allowed to stand after standing at 85 ° C and 85% RH for 500 hours.

According to an embodiment of the invention, the anisotropic conductive film has a melt viscosity variation of from 0 to about 0.2, as calculated by Equation 3: Melt viscosity variation = log│ (film measured at 75 ° C) Melt viscosity - melt viscosity of the film measured at 55 ° C) │ / (75 ° C - 55 ° C).

According to an embodiment of the invention, the two inorganic fillers are present in an amount of from 20 wt% to 80 wt%, based on the total weight of the anisotropic conductive film.

According to an embodiment of the invention, two inorganic fillers are contained in each of the conductive layer and the dielectric layer.

According to an embodiment of the invention, the two inorganic fillers include a first inorganic filler having a particle diameter of 1 nm to 40 nm and a second inorganic filler having a particle diameter of 50 nm to 1,000 nm.

According to an embodiment of the invention, the weight ratio of the first inorganic filler to the second inorganic filler ranges from 1:2 to 1:10.

According to an embodiment of the invention, the second inorganic filler is surface treated with a compound selected from the group consisting of phenylamine, vinyl, phenyl, epoxy and methacryl.

According to an embodiment of the invention, each of the conductive layer and the dielectric layer further comprises a binder resin, an epoxy resin, and a curing agent.

According to an embodiment of the invention, the anisotropic conductive film is used in a chip on glass (COG) mounting method.

According to another aspect of the present invention, a connection structure is provided, comprising: a first connection member including a first electrode; a second connection member including a second electrode; and an anisotropic conductive film disposed on Between the first connecting member and the second connecting member to connect the first electrode to the second electrode, the anisotropic conductive film being an anisotropic conductive film as set forth above.

According to the present invention, it is possible to provide an anisotropic conductive film having improved dispersibility of conductive particles, thereby exhibiting excellent characteristics in terms of insulation efficiency and connection reliability.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, descriptions of details apparent to those skilled in the art will be omitted for clarity.

One aspect of the present invention is directed to an anisotropic conductive film comprising: a conductive layer, a dielectric layer, and two inorganic fillers having different particle diameters, wherein the dielectric layer has a higher expanded length than the conductive layer The rate of increase is calculated as calculated by Equation 1, and the anisotropic conductive film has a storage modulus of from about 2.5 GPa to about 5 GPa, as measured by a cure rate of 90% or higher. <Equation 1> Expansion length increase rate (%) = {(lateral length of the target layer after main compression - lateral length of the target layer before preliminary compression) / lateral length of the target layer before preliminary compression} ×100

The reason why the dielectric layer has a higher expansion length increase rate than the conductive layer is that the dielectric layer has a higher fluidity than the conductive layer. Therefore, it is possible to easily fill the dielectric layer between the terminals due to higher fluidity, and it is possible to suppress the flow of the conductive particles into the space portion due to the lower fluidity of the conductive layer, thereby preventing the short circuit.

The dielectric layer can have a rate of expansion length increase of from about 60% to about 120%, specifically from about 70% to about 115%, and more specifically from about 75% to about 110%. For example, the dielectric layer can have a rate of expansion length increase of about 60%, about 70%, about 80%, about 90%, about 100%, about 110%, or about 120%.

The electrically conductive layer can have a rate of expansion length increase of from about 10% to about 60%, specifically from about 20% to about 50%, and more specifically from about 25% to about 45%. For example, the conductive layer can have a rate of expansion length increase of about 10%, about 20%, about 30%, about 40%, about 50%, or about 60%.

When the expansion length of each layer increases in the above range, the dielectric layer can be uniformly filled between the terminals, and the anisotropic conductive film can exhibit improved connection reliability.

In one embodiment, the difference between the rate of increase of the expanded length of the conductive layer and the rate of increase of the expanded length of the dielectric layer ranges from about 40% to about 80%, in particular, it is between about 40%. Up to about 60%. For example, the difference between the rate of increase in the expanded length of the conductive layer and the rate of increase in the expanded length of the dielectric layer can range from about 40%, about 50%, about 60%, about 70%, or about 80%. Within this range, the anisotropic conductive film exhibits further improved characteristics in terms of insulation efficiency and connection reliability.

A non-limiting example of a method of measuring the rate of expansion of the expanded length is as follows: After preparing an anisotropic conductive film sample having a size of 2 mm × 20 mm (width × length), the glass substrate is placed on two of the samples On the side, it was initially compressed at 70 ° C and 1.0 MPa for 1 second and at 150 ° C and 80 MPa for 5 seconds. The lateral length of the target layer is measured before and after the compression process, and then the expansion length increase rate (%) of the target layer is calculated according to Equation 1.

The anisotropic conductive film may have a storage modulus of from about 2.5 GPa to about 5 GPa, as measured at a curing rate of 90% or higher. Specifically, the anisotropic conductive film may have a storage modulus of from about 3 GPa to about 5 GPa, more specifically from about 3.5 GPa to about 4.5 GPa. For example, the anisotropic conductive film may have a storage modulus of about 2.5 GPa, about 3 GPa, about 3.5 GPa, about 4 GPa, about 4.5 GPa, or about 5 GPa, such as a cure rate of 90% or higher. Measured. Here, a curing rate of 90% or more generally means that the anisotropic conductive film is completely cured.

Within the above range of the storage modulus, the anisotropic conductive film may have a desired viscosity without lowering the fluidity of the dielectric layer, thereby improving the shape stability of the film while preventing short-circuiting between the terminals.

Without limitation, the storage modulus can be measured by any method known in the art. For example, the anisotropic conductive film can be placed in a hot air oven at 150 ° C for 2 hours, and then the film is measured at 40 ° C using a dynamic mechanical analyzer (DMA) (Q800, TA Instruments). The storage modulus.

The anisotropic conductive film according to an embodiment of the present invention may have a two-layer structure of a conductive layer and a dielectric layer. In particular, the anisotropic conductive film may have a structure in which a dielectric layer is stacked on the conductive layer.

As used herein, the term "stacking" means that one layer is formed on the surface of another layer and is interchangeable with "coating" or "lamination." When the anisotropic conductive film has a two-layer structure of a conductive layer and a dielectric layer, the anisotropic conductive film may have appropriate fluidity without interfering with compression of the conductive particles.

The anisotropic conductive film may contain two inorganic fillers having different particle diameters. When the anisotropic conductive film contains two kinds of inorganic fillers having different particle diameters, it is possible to improve the dispersibility of the conductive particles, thereby preventing short-circuiting and improving connection characteristics while increasing film formability.

The inorganic filler may include, without limitation, any suitable inorganic filler known in the art. Examples of the inorganic filler may include alumina, ceria, titania, zirconia, magnesia, ceria, zinc oxide, iron oxide, tantalum nitride, titanium nitride, boron trioxide, calcium carbonate, aluminum sulfate , aluminum hydroxide, calcium titanate, talc, calcium citrate and magnesium citrate, but are not limited thereto. Specifically, the inorganic filler may be alumina, ceria, calcium carbonate or aluminum hydroxide. In one embodiment, the inorganic filler can be alumina or ceria.

The inorganic filler may be surface-treated with a compound such as a phenylamine group, a phenyl group, a methacryl group, a vinyl group, and an epoxy group to improve the dispersibility in the anisotropic conductive film.

The method of surface-treating the inorganic filler is not particularly limited. For example, a dry surface treatment can be performed using a Henschel mixer in which a surface treatment agent is directly mixed with an inorganic filler, followed by heat treatment as needed. Alternatively, a surface treatment agent diluted with a suitable solvent can be used.

The two inorganic fillers may be included in any of the conductive layer and the dielectric layer and may be included in the conductive layer and the dielectric layer, respectively, or may be included in both the conductive layer and the dielectric layer. In particular, two inorganic fillers can be included in both the conductive layer and the dielectric layer.

The two inorganic fillers may be from about 20 wt% to about 80 wt%, specifically from about 30 wt% to about 70 wt%, and more specifically about 35 wt%, based on the total weight of the anisotropic conductive film. It is present in an amount of about 65 wt%. Within this range, it is possible to effectively disperse the conductive particles and appropriately adjust the fluidity of the anisotropic conductive film.

When the two inorganic fillers are included in both the conductive layer and the dielectric layer, the two inorganic fillers may be from about 20 wt% to about 50 wt%, specifically about 20 wt%, based on the total weight of the conductive layer. An amount of up to about 40 wt% is present in the conductive layer and may be present in an amount from about 30 wt% to about 80 wt%, specifically from about 40 wt% to about 70 wt%, based on the total weight of the dielectric layer. In the dielectric layer.

In one embodiment, the two inorganic fillers may comprise a first inorganic filler having a particle size of from about 1 nm to about 40 nm and a second inorganic filler having a particle size of from about 50 nm to about 1,000 nm.

The first inorganic filler having a particle diameter of about 1 nm to about 40 nm serves to reduce the surface tension of the anisotropic conductive film, thereby allowing easy coating of the film and preventing delamination of the film after curing. Thereby, the film formability is improved. In particular, the first inorganic filler may have a particle size of from about 1 nm to about 30 nm, more specifically from about 1 nm to about 10 nm.

A second inorganic filler having a particle diameter of about 50 nm to about 1,000 nm is placed between the conductive particles to improve the dispersibility of the conductive particles, and is used to increase the storage modulus, thereby increasing the particle capture rate and reducing Small short circuit occurrence rate. In particular, the second inorganic filler may have a particle size of from about 50 nm to about 800 nm, more specifically from about 50 nm to about 500 nm.

The weight ratio of the first inorganic filler to the second inorganic filler may range from about 1:2 to about 1:10, specifically from about 1:2 to about 1:8, and more specifically from about 1:3 to About 1:5. Within this range, the anisotropic conductive film can have appropriate fluidity and viscosity while exhibiting excellent particle capture ratio and improved film formability.

In one embodiment, the conductive layer of the anisotropic conductive film may further include a binder resin, an epoxy resin, a curing agent, and conductive particles.

Examples of the binder resin may include a polyimide resin, a polyamide resin, a phenoxy resin, a polymethacrylate resin, a polyacrylate resin, a polyurethane resin, a polyester resin, a polyester urethane. Ester resin, polyvinyl butyral resin, styrene-butylene-styrene (SBS) resin, and modified epoxy resin, styrene-ethylene-butylene-styrene (styrene- Ethylene-butylene-styrene; SEBS) resin and its modified product, acrylonitrile butadiene rubber (NBR) and hydrogenated products thereof; and combinations thereof. Specifically, the binder resin may be a phenoxy resin, more specifically an anthracene phenoxy resin. The anthraquinone phenoxy resin may include, without limitation, any phenoxy resin having a fluorene structure.

The binder resin may be present in an amount of from about 10% by weight to about 40% by weight based on the total weight of the anisotropic conductive film. In particular, the binder resin may be present in an amount from about 10% to about 30% by weight.

Examples of the epoxy resin may include: bisphenol epoxy resin such as bisphenol A epoxy resin, bisphenol A epoxy acrylate resin, bisphenol F epoxy resin, bisphenol AD epoxy resin, bisphenol E epoxy Resin and bisphenol S epoxy resin; aromatic epoxy resin, such as polyglycidyl ether epoxy resin, polyglycidyl epoxy resin and naphthalene epoxy resin; alicyclic epoxy resin; novolac epoxy resin, Such as cresol novolac type epoxy resin and phenol novolak type epoxy resin; glycidylamine epoxy resin; glycidyl ester epoxy resin; diphenyl diglycidyl ether epoxy resin; and the like. These resins may be used singly or as a mixture thereof. Specifically, the epoxy resin may be an alicyclic epoxy resin. Since the alicyclic epoxy resin has an epoxy resin structure close to the alicyclic ring, the alicyclic epoxy resin has a higher degree of ring opening reactivity than other epoxy resins, and thus has high curability. The alicyclic epoxy resin according to the present invention may be any alicyclic epoxy resin as long as the alicyclic epoxy resin has an epoxy resin structure coupled to the alicyclic ring in a direct manner or via another bonding group.

The epoxy resin may be from about 10 wt% to about 40 wt%, specifically from about 10 wt% to about 35 wt%, more specifically from about 15 wt% to about 30, based on the total weight of the anisotropic conductive film. The amount of wt% exists.

The weight ratio of binder resin to epoxy resin can range from about 4:6 to about 6:4. Within this range, the anisotropic conductive film can have stable adhesion after thermal compression in its manufacturing process. In particular, the weight ratio can range from about 4:6 to about 5:5.

The curing agent may be any curing agent as long as the curing agent can cure the epoxy resin, thereby forming an anisotropic conductive film. Examples of the curing agent may include an acid anhydride, an amine, an imidazole, an isocyanate, a guanamine, an anthracene, a phenol, and a cationic curing agent. Specifically, the curing agent may be a cationic curing agent or an amine curing agent. The cationic curing agent can rapidly cure the epoxy resin, and the amine curing agent has an advantage in stabilizing the non-isotropic conductive film, thereby reducing the consumption of the stabilizer. In one embodiment, the curing agent can be a hydrazine curing agent.

The curing agent may be present in an amount of from about 1 wt% to about 10 wt%, specifically from about 1 wt% to about 5 wt%, based on the total solid weight of the anisotropic conductive film. Within this range, the curing agent can sufficiently cure the anisotropic conductive film, and the anisotropic conductive film can have an appropriate molecular weight and thus can exhibit excellent characteristics in terms of adhesion and reliability after bonding.

The electrically conductive particles may include, without limitation, any suitable electrically conductive particles known in the art. Examples of the conductive particles may include metal particles such as Au, Ag, Ni, Cu, solder particles; carbon; conductive particles obtained by plating particles of the resin, such as polyethylene, polypropylene, polyester, Polystyrene and polyvinyl alcohol and modified products thereof having metals such as Au, Ag, and Ni; and insulating conductive particles obtained by coating the above-mentioned conductive particles with insulating particles. For example, the conductive particles may have a size of from about 1 μm to about 20 μm, specifically from about 1 μm to about 10 μm, but the size may vary depending on the pitch of the circuit to which the anisotropic conductive film is applied.

The conductive particles may be present in an amount of from about 1 wt% to about 50 wt%, specifically from about 10 wt% to about 35 wt%, based on the total weight of the anisotropic conductive film. Within this range, the conductive particles can be easily compressed between the terminals, thereby maintaining stable connection reliability while improving current-carrying characteristics, thereby reducing connection resistance.

In one embodiment, the anisotropic conductive film may further comprise a decane coupling agent.

The decane coupling agent may comprise at least one selected from the group consisting of a fluorene-containing compound containing a polymerizable unsaturated group, such as vinyltrimethoxysilane, vinyltriethoxysilane. And (meth)acryloxypropyltrimethoxysilane; an oxime compound having an epoxy resin structure, such as 3-glycidoxypropyltrimethoxysilane , 3-glycidoxypropylmethyldimethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxydecane (2-(3,4-epoxycyclohexyl)) Ethyltrimethoxysilane); an amine group-containing hydrazine compound such as 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxydecane (N) -(2-aminoethyl)-3-aminopropyltrimethoxysilane) and N-(2-aminoethyl)-3-aminopropylmethyldimethoxydecane (N-(2-aminoethyl)-3-aminopropylmethyldimetho Xysilane); and 3-chloropropyltrimethoxysilane, but is not limited thereto.

The decane coupling agent may be present in an amount of from about 1% by weight to about 10% by weight based on the total weight of the anisotropic conductive film.

In another embodiment, the anisotropic conductive film may further contain additives such as a polymerization inhibitor, an antioxidant, and a heat stabilizer to provide additional characteristics without changing the basic characteristics. The additive may be present in an amount of from about 0.01 wt% to about 10 wt%, based on the total weight of the anisotropic conductive film, but is not limited thereto.

Examples of the polymerization inhibitor may include hydroquinone, hydroquinone monomethyl ether, p-benzoquinone, phenothiazine, and a mixture thereof. The antioxidant can be a phenol or a hydroxycinnamate antioxidant. For example, the antioxidant may comprise tetrakis[methylene (3,5-di-t-butyl-4-hydroxycinnamate)]methane (tetrakis[methylene(3,5-di-t-butyl-4) -hydroxycinnamate)]methane), 3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionic acid thiodi-2,1-ethanediester (3,5-bis (1,1-dimethylethyl)-4-hydroxybenzenepropanoic acid thiodi-2,1-ethanediyl ester) and the like.

The dielectric layer may comprise components further included in the conductive layer, with the exception of conductive particles. The details of each of the components are the same as described above.

The anisotropic conductive film may have a particle capture ratio of about 20% to about 60%, as calculated by Equation 2: particle capture rate (%) = (per unit area in the joint region after main compression ( Mm ² ) the number of conductive particles / the number of conductive particles per unit area (mm ² ) of the anisotropic conductive film before the preliminary compression) × 100 wherein the temperature is from 50 ° C to 80 ° C and from 1.0 MPa to 3.0 MPa The preliminary compression is performed under pressure for 1 to 3 seconds, and the main compression is performed for 3 to 6 seconds at a temperature of 120 ° C to 160 ° C and a pressure of 60 MPa to 90 MPa.

In particular, the anisotropic conductive film may have a particle capture ratio of from about 25% to about 55%, more specifically from about 30% to about 50%. For example, the anisotropic conductive film can have a particle capture rate of about 20%, about 30%, about 40%, about 50%, or about 60%, as calculated by Equation 2.

In the range of the above-described particle trapping rate, the fluidity of the conductive layer can be effectively suppressed, so that the conductive particles can be sufficiently placed on the terminals to improve the current-carrying characteristics and to reduce the outflow of the conductive particles, thereby reducing the terminal. Short circuit between.

The method of measuring the particle capture rate is not particularly limited, and a non-limiting example thereof is as follows. First, the number of conductive particles per unit area (mm ² ) of the anisotropic conductive film before compression was calculated using an automatic particle counter. Next, an anisotropic conductive film is placed on a glass substrate including an ITO circuit having a bump area of 1,200 μm ² and a thickness of 2,000 Å, followed by preliminary compression at 70 ° C and 1 MPa for 1 second, and After removing the release film, an IC wafer having a bump area of 1,200 μm ² and a thickness of 1.5 T was placed on the anisotropic conductive film, followed by main compression at 150 ° C and 80 MPa for 5 seconds, and The number of conductive particles in the connected region was calculated using an automatic particle counter, and then the particle capture rate was calculated according to Equation 2.

The anisotropic conductive film may have a minimum melt viscosity of from about 1,000 Pa·s to about 100,000 Pa·s, as measured at a temperature of from 50 ° C to 100 ° C. Specifically, the anisotropic conductive film may have a minimum melt viscosity of from about 10,000 Pa·s to about 100,000 Pa·s. Within this range, the anisotropic conductive film can exhibit appropriate fluidity, thereby improving the trapping of the conductive particles.

The method of measuring the minimum melt viscosity is not particularly limited, and a non-limiting example thereof is as follows: using an ARES G2 rheometer (TA Instruments) at a sample thickness of 150 μm, a heating rate of 10 ° C/min, a strain of 5%, The minimum melt viscosity of the anisotropic conductive film was measured under the conditions of an angular frequency of 1.0 rad/sec and a temperature range of 0 ° C to 250 ° C.

The anisotropic conductive film may have a melt viscosity variation of from 0 to about 0.2, preferably from 0 to about 0.17, as calculated by Equation 3: Melt viscosity variation = log│ (measured at 75 ° C) Melt viscosity of the film - melt viscosity of the film measured at 55 ° C) │ / (75 ° C - 55 ° C).

Within the range of the above-mentioned melt viscosity variation, the minimum melt viscosity can be maintained within a certain temperature range, so that the film composition can have excellent fluidity, thereby improving the indentation characteristics.

The anisotropic conductive film may have a connection resistance of 5 Ω or less (specifically, 3 Ω or less, more specifically 2 Ω or less) after the reliability test, such as 50 ° C to 80 ° C Temperature and initial compression for 1 to 3 seconds at a pressure of 1.0 MPa to 3.0 MPa and a temperature of 120 ° C to 160 ° C and a main compression for 3 to 6 seconds at a pressure of 60 MPa to 90 MPa and then allow the anisotropic conductive film at 85 Measured after standing for 500 hours at ° C and 85% relative humidity (RH).

The anisotropic conductive film can exhibit improved connection reliability and long-term stability within the range of the connection resistance after the above reliability test.

The method of measuring the connection resistance after the reliability test is not particularly limited, and a non-limiting example thereof is as follows. First, an anisotropic conductive film is placed on a glass substrate including an ITO circuit having a bump area of 1,200 μm ² and a thickness of 2,000 Å, followed by preliminary compression at 70 ° C and 1 MPa for 1 second, and After removing the release film, an IC wafer having a bump area of 1,200 μm ² and a thickness of 1.5 T was placed on the anisotropic conductive film, followed by main compression at 150 ° C and 80 MPa for 5 seconds. This preparation of the specimen. Next, the resistance value between the four points of the prepared specimen was measured by a 4-point probe method using a resistance meter (20 million meter, Keithley Instruments), thereby finding the initial connection resistance. Next, the specimen was allowed to stand at 85 ° C and 85% RH for 500 hours, and then the resistance was measured in the same manner, thereby finding the connection resistance after the reliability test. Here, the value of the resistance is calculated by a resistance meter based on the voltage value measured after applying a current of 1 mA, and then the value of the resistance is averaged.

The anisotropic conductive film may have an initial occurrence rate of short circuit of 0%, such as a temperature of 50 ° C to 80 ° C and a pressure of 1.0 MPa to 3.0 MPa for preliminary compression of 1 to 3 seconds and a temperature of 120 ° C to 160 ° C and 60 Measured after 1 to 5 seconds of main compression at a pressure of MPa to 90 MPa.

The anisotropic conductive film can reduce the circuit driving voltage within the range of the initial occurrence of the short circuit described above.

The method of measuring the initial occurrence rate of the short circuit is not particularly limited, and a non-limiting example thereof is as follows. After the anisotropic conductive film was cut into a specimen having a size of 2 mm × 25 mm, the specimen was bonded to a material for insulation resistance evaluation, and then the occurrence rate of the short circuit was measured. More specifically, the film specimen was placed on a 0.5 mm thick glass substrate, and then the release film was removed after heating/pressing at 70 ° C, 1 MPa for 1 second. Next, a wafer (length: 19.5 mm, width: 1.5 mm, bump pitch: 8 μm) was placed on the film specimen, followed by main compression at 150 ° C and 70 MPa for 1 second, thereby manufacturing a circuit device. Next, the occurrence of a short circuit at 38 points was examined by a two-terminal method at a voltage of 50 V, thereby measuring the initial occurrence rate of the short circuit.

The anisotropic conductive film has a 0% short-circuit occurrence rate after the reliability test, such as a temperature of 50 ° C to 80 ° C and a preliminary compression of 1 to 3 seconds and 120 ° C to 160 ° C at a pressure of 1.0 MPa to 3.0 MPa. The temperature was compressed at a pressure of 60 MPa to 90 MPa for 1 to 5 seconds and then allowed to stand after standing at 85 ° C and 85% RH for 500 hours.

The anisotropic conductive film can continuously maintain the circuit driving voltage at a low level within the range of the occurrence rate of the short circuit after the reliability test described above, thereby providing long-term stability.

The method of measuring the occurrence rate of the short circuit after the reliability test is not particularly limited, and a non-limiting example thereof is as follows. After the circuit device for measuring the initial occurrence rate of the short circuit was allowed to stand at 85 ° C and 85% RH for 500 hours, the occurrence rate of the short circuit after the reliability test was measured in the same manner as the initial occurrence rate of the measurement short circuit.

In one embodiment, an anisotropic conductive film can be used in a chip on film (COF) mounting method.

Next, a method of manufacturing an anisotropic conductive film according to another aspect of the present invention will be described.

The anisotropic conductive film according to this embodiment can be fabricated without using special equipment or facilities. For example, an anisotropic conductive film composition containing a component as set forth above is dissolved in an organic solvent such as toluene, followed by stirring for a certain period of time at a stirring speed which does not cause extrusion of the conductive particles, And the agitated film composition is applied onto the release film until a thickness of, for example, 5 μm to 50 μm, and then dried for a certain period of time to volatilize toluene and the like, thereby obtaining anisotropic conductivity membrane.

Next, a connection structure according to another aspect of the present invention will be described.

The connection structure may include: a first connection member including a first electrode; a second connection member including a second electrode; and an anisotropic conductive film disposed between the first connection member and the second connection member The first electrode is connected to the second electrode, wherein the anisotropic conductive film may be an anisotropic conductive film according to an embodiment of the present invention.

The first connecting member or the second connecting member includes an electrode. Specifically, the first connecting member or the second connecting member may be a glass or plastic substrate, a printed wiring board, a ceramic wiring board, a flexible wiring board, a semiconductor germanium wafer, an IC wafer or a driver IC chip, which is formed for an LCD Indium tin oxide (ITO) or indium zinc oxide (IZO) electrodes. More specifically, one of the first connection member and the second connection member may be an IC wafer or a driver IC wafer, and the other may be a glass substrate.

Referring to FIG. 1, the connection structure 30 may include: a first connection member 50 including a first electrode 70; a second connection member 60 including a second electrode 80; and an anisotropic conductive film 10 disposed on the first connection member The first electrode and the second electrode are connected with the second connecting member, wherein the anisotropic conductive film may be an anisotropic conductive film containing the conductive particles 3 as explained above.

Next, the present invention will be described in more detail with reference to some examples. However, it is to be understood that the examples are provided for illustration only and are not to be construed as limiting the invention in any way.

For the sake of clarity, a description of the details that are apparent to those skilled in the art will be omitted. Example Example 1 1. Formation of conductive layer

20 wt% of a dibenzazole type binder resin (FX-293, Nippon Steel Chemical Co., Ltd., Tg: 165 ° C, molecular weight: 45,000), 10 wt% of epoxy as a first inorganic filler Resin 1 (Celloxide 2021P, DAICEL), 5 wt% epoxy resin 2 (YDPN 638, Kukdo Chemical Company), 2 wt% cationic curing agent (SI-B3A, Sanshin Chemical Industry Co., Ltd.), conductive particles (KSFD, average particle size: 3.0 μm, NCI), 3 wt% of cerium oxide having a particle size of 7 nm (R812, Tokuyama corporation) and 20 wt% of a second inorganic filler having a particle diameter of 50 nm Further, cerium oxide (YA050C, Admatech) surface-treated with a phenylamine group was used to prepare a conductive layer composition. The conductive layer composition was applied onto a release film, followed by volatilization of the solvent at 70 ° C for 5 minutes using a drier, thereby obtaining a 6 μm thick dry conductive layer. 2. Formation of dielectric layer

A 12 μm thick dry dielectric layer was formed in the same manner as the conductive layer, except that conductive particles were not used and their amounts were changed as listed in Table 1. 3. Manufacture of anisotropic conductive film

The conductive layer was bonded to the dielectric layer via lamination at 40 ° C and 1 MPa, whereby an anisotropic conductive film (thickness: 18 μm) having a two-layer structure in which the dielectric layer was stacked on the conductive layer was obtained. Example 2

An anisotropic conductive film was produced in the same manner as in Example 1, except that cerium oxide (PM-20, Tokuyama) having a particle diameter of 14 nm was used as the first inorganic filler. Example 3

An anisotropic conductive film was produced in the same manner as in Example 1, except that ceria having a particle diameter of 500 nm and surface-treated with an epoxy resin (SC2030, Admatech) was used as the second inorganic filler. Example 4

An anisotropic conductive film was produced in the same manner as in Example 1, except that the amount of each component listed in Table 1 was changed. Comparative example 1

An anisotropic conductive film was produced in the same manner as in Example 1 except that the second inorganic filler was not used and its amount of each component as listed in Table 1 was changed. Comparative example 2

An anisotropic conductive film was produced in the same manner as in Example 1 except that the first inorganic filler was not used and the amount of each component as listed in Table 1 was changed.

Details of each of the components used in the examples and comparative examples are shown in Table 1. The amount of each component is measured in wt%. Table 1 Experimental example

According to the following method, the length increase rate, the storage modulus, the minimum melt viscosity, the particle trap rate, the initial connection resistance, and the connection resistance after the reliability test and the initial occurrence rate of the short circuit and the occurrence rate of the short circuit after the reliability test are developed. Each of the anisotropic conductive films fabricated in Examples 1 to 4 and Comparative Examples 1 and 2 was evaluated. The results are shown in Table 2. Experimental Example 1: Measurement of the expansion length increase rate

After preparing an anisotropic conductive film sample having a size of 2 mm × 20 mm (width × length), the glass substrate was placed on both sides of the sample, and then initially compressed at 70 ° C and 1.0 MPa for 1 second. And main compression at 150 ° C and 80 MPa for 5 seconds. The lateral length of the target layer before and after compression is measured, whereby the expansion length increase rate (%) is calculated according to Equation 1. <Equation 1> Expansion length increase rate (%) = {(lateral length of the target layer after main compression - lateral length of the target layer before preliminary compression) / lateral length of the target layer before preliminary compression} ×100 Experimental Example 2: Measurement of storage modulus

Each of the manufactured anisotropic conductive films was placed in a hot air oven at 150 ° C for 2 hours, followed by a dynamic mechanical analyzer (DMA) (Q800, TA Instruments) at a temperature of 0 ° C to 100 ° C The storage modulus of the film at 40 ° C was measured in the range at a heating rate of 5 ° C / min. Experimental Example 3: Measurement of Minimum Melt Viscosity

Using an ARES G2 rheometer (TA Instruments) at a sample thickness of 150 μm, a heating rate of 10 ° C/min, a strain of 5%, an angular frequency of 1.0 rad/sec, and a temperature range of 0 ° C to 250 ° C The minimum melt viscosity of each of the manufactured anisotropic conductive films was measured. Experimental Example 4: Measurement of Melt Viscosity Variance

The melt viscosity of each of the produced anisotropic conductive films was measured using an ARES G2 rheometer (TA Instruments) at 75 ° C and 55 ° C, and then the melt viscosity variation was calculated according to Equation 3: Melt viscosity variation Number = log │ (melting viscosity of the film measured at 75 ° C - melt viscosity of the film measured at 55 ° C) │ / (75 ° C - 55 ° C). Experimental Example 5: Measurement of particle capture rate

For each of the anisotropic conductive films, an automatic particle counter (ZOOTUS) was used to calculate the number of conductive particles per unit area (mm ² ) of the film before the preliminary compression. Next, an anisotropic conductive film was placed on a glass substrate including an ITO circuit having a bump area of 1,200 μm ² and a thickness of 2,000 Å (NEOVIEW KOLON, INC.), followed by 70 ° C and 1 MPa. The initial compression was performed for 1 second, and after removing the release film, an IC wafer (SAMSUNG LSI) having a bump area of 1,200 μm ² and a thickness of 1.5 T was placed on the anisotropic conductive film, followed by 150 Main compression at °C and 80 MPa for 5 seconds, and the number of conductive particles in the connected region was calculated using an automatic particle counter, and then the particle capture rate (mm ² ) was calculated according to Equation 2: Particle capture rate (%) = (in the main compression per unit area (mm ²⁾ number of conductive particles / 6 × 100 per unit area experimental example anisotropically conductive film before preliminary compression (mm ²⁾ number of the conductive particles) in the connection region after: initial connection Resistance and measurement of connection resistance after reliability test

Each of the anisotropic conductive films was placed on a glass substrate including an ITO circuit having a bump area of 1,200 μm ² and a thickness of 2,000 Å (NEOVIEW KOLON, INC.), followed by 70 ° C And preliminary compression for 1 second at 1 MPa, and after removing the release film, an IC wafer (SAMSUNG LSI) having a bump area of 1,200 μm ² and a thickness of 1.5 T was placed on the anisotropic conductive film. The specimen was then prepared by main compression at 150 ° C and 80 MPa for 5 seconds. Next, the resistance value between the four points of the prepared specimen was measured by a 4-point probe method using a resistance meter (20 million meter, Keithley Instruments), thereby finding the initial connection resistance. Next, the specimen was allowed to stand at 85 ° C and 85% RH for 500 hours, and then the resistance was measured in the same manner, thereby finding the connection resistance after the reliability test. Here, the resistance value is calculated by a resistance meter based on the voltage value measured after applying a current of 1 mA, and then the resistance value is averaged. Experimental Example 7: Initial occurrence of short circuit and measurement of short circuit occurrence rate after reliability test

Each of the anisotropic conductive films was cut into a specimen having a size of 2 mm × 25 mm, and the specimen was joined to a material for insulation resistance evaluation, and then the occurrence rate of the short circuit was measured. More specifically, the film specimen was placed on a 0.5 mm thick glass substrate, and then the release film was removed after heating/pressing at 70 ° C, 1 MPa for 1 second. Next, a wafer (length: 19.5 mm, width: 1.5 mm, bump pitch: 8 μm) was placed on the film specimen, followed by main compression at 150 ° C and 70 MPa for 1 second, thereby manufacturing a circuit device. Next, the occurrence of a short circuit at 38 points was examined by a two-terminal method at a voltage of 50 V, thereby measuring the initial occurrence rate of the short circuit. Next, the circuit device was allowed to stand at 85 ° C and 85% RH for 500 hours, and then the short-circuit occurrence rate after the reliability test was measured in the same manner as described above. Table 2

As shown in Table 2, it can be seen that the anisotropic conductive films of Examples 1 to 4 containing two kinds of inorganic fillers having different particle diameters have a melt viscosity variation of 0 to 0.2 and a storage of 2.5 GPa to 5 GPa. Modulus, and exhibits improved characteristics in terms of particle capture rate, initial connection resistance, and connection resistance after reliability testing and short circuit occurrence. Further, in the anisotropic conductive films of Examples 1 to 4, the dielectric layer has a higher expansion length increase rate than the conductive layer.

In contrast, the non-isotropic conductive film of Comparative Example 1 which does not contain ceria having a particle diameter of 50 nm to 1,000 nm between the two inorganic fillers has a low particle capture ratio after the reliability test and thus has The high connection resistance, although not problematic in terms of initial connection efficiency, exhibits poor insulation performance and high short circuit occurrence due to high melt viscosity variation. In the anisotropic conductive film of Comparative Example 2 which does not contain cerium oxide having a particle diameter of 1 nm to 40 nm, the conductive layer has poor film formability and conductive particles in the conductive layer are therefore likely to coalesce, The initial connection resistance and the connection resistance after the reliability test are deteriorated. The anisotropic conductive film of Comparative Example 2 exhibited poor insulation performance due to the high melt viscosity variation number and thus exhibited a high short circuit occurrence rate.

3‧‧‧ Conductive particles

10‧‧‧A non-isotropic conductive film

30‧‧‧ Connection structure

50‧‧‧First connecting parts

60‧‧‧Second connection parts

70‧‧‧First electrode

80‧‧‧second electrode

1 is a cross-sectional view of a connection structure 30 including: a first connection member 50 including a first electrode 70; a second connection member 60 including a second electrode 80; and anisotropy, in accordance with an embodiment of the present invention. The conductive film 10 is disposed between the first connecting member and the second connecting member to connect the first electrode and the second electrode via the conductive particles 3.

Claims (15)

An anisotropic conductive film comprising: a conductive layer, a dielectric layer, and two inorganic fillers having different particle diameters, wherein the two inorganic fillers are included in the conductive layer and the dielectric layer In at least one of the two, the inorganic filler includes a first inorganic filler having a particle diameter of 1 nm to 40 nm and a second inorganic filler having a particle diameter of 50 nm to 1,000 nm, wherein Calculated by Equation 1, the expanded length of the dielectric layer is increased at a rate higher than the expanded length of the conductive layer, and the anisotropy is measured as measured at a curing rate of 90% or higher. The conductive film has a storage modulus of about 2.5 GPa to about 5 GPa: <Equation 1> Expansion length increase rate (%) = {(the lateral length of the target layer after the main compression minus the target layer before the preliminary compression) The transverse length) is a ratio of the lateral length of the target layer before the preliminary compression}×100 wherein the preliminary compression is performed for 1 to 3 seconds at a temperature of 50 ° C to 80 ° C and a pressure of 1.0 MPa to 3.0 MPa, and at 120 The main compression is carried out for 3 to 6 seconds at a temperature of from ° C to 160 ° C and a pressure of from 60 MPa to 90 MPa. The anisotropic conductive film according to claim 1, wherein the dielectric layer has a growth rate increase ratio of 60% to 120%, and the conductive layer has 10% to 60% The deployment length increases the rate. The anisotropic conductive film according to claim 1, wherein a difference between a rate of increase of the developed length of the conductive layer and a rate of increase of the developed length of the dielectric layer is Between 40% and 80%. The anisotropic conductive film according to claim 1, wherein the anisotropic conductive film has a particle capture ratio of about 20% to about 60% as calculated by Equation 2: Formula 2>Particle capture ratio (%) = (number of conductive particles per unit area (mm ² ) in the connection region after main compression and per unit area of the anisotropic conductive film before preliminary compression (mm ² a ratio of the number of conductive particles) × 100, wherein the preliminary compression is performed at a temperature of 50 ° C to 80 ° C and a pressure of 1.0 MPa to 3.0 MPa for 1 to 3 seconds, and at a temperature of 120 ° C to 160 ° C and 60 MPa The main compression was carried out for 3 to 6 seconds under a pressure of 90 MPa. The anisotropic conductive film according to claim 1, wherein the preliminary compression is performed at a temperature of 50 ° C to 80 ° C and a pressure of 1.0 MPa to 3.0 MPa for 1 to 3 seconds and at 120 ° C to The main compression was performed at a temperature of 160 ° C and a pressure of 60 MPa to 90 MPa for 3 to 6 seconds and then the anisotropic conductive film was allowed to stand at 85 ° C and 85% RH for 500 hours, which was measured. The anisotropic conductive film has a connection resistance of 5 Ω or less after performing reliability test. The anisotropic conductive film according to claim 1, wherein the anisotropic conductive film has a minimum melting of 1,000 to 100,000 Pa ‧ as measured at a temperature of 50 ° C to 100 ° C Viscosity. The anisotropic conductive film according to claim 1, wherein the preliminary compression is performed at a temperature of 50 ° C to 80 ° C and a pressure of 1.0 MPa to 3.0 MPa for 1 to 3 seconds and at 120 ° C to The main compression was measured after a temperature of 160 ° C and a pressure of 60 MPa to 90 MPa, and the anisotropic conductive film had a 0% short-circuit initial occurrence rate. The anisotropic conductive film according to claim 1, wherein the preliminary compression is performed at a temperature of 50 ° C to 80 ° C and a pressure of 1.0 MPa to 3.0 MPa for 1 to 3 seconds and at 120 ° C to The main compression was performed at a temperature of 160 ° C and a pressure of 60 MPa to 90 MPa for 1 to 5 seconds and then the anisotropic conductive film was allowed to stand at 85 ° C and 85% RH for 500 hours, which was measured. The anisotropic conductive film has a 0% short-circuit occurrence rate after performing the reliability test. The anisotropic conductive film according to claim 1, wherein the anisotropic conductive film has a melt viscosity variation of 0 to about 0.2 as calculated by the equation 3: a melt viscosity variation number =log|(The melt viscosity of the film measured at 75 ° C minus the melt viscosity of the film measured at 55 ° C) | / (20 ° C). The anisotropic conductive film according to claim 1, wherein the two inorganic fillers are present in an amount of 20% by weight to 80% by weight based on the total weight of the anisotropic conductive film. The anisotropic conductive film according to claim 1, wherein the weight ratio of the first inorganic filler to the second inorganic filler ranges from 1:2 to 1:10. The anisotropic conductive film according to claim 1, wherein the second inorganic filler is surface-treated with a compound selected from the group consisting of phenylamine, vinyl, Phenyl, epoxy and methacrylic groups. The anisotropic conductive film of claim 1, wherein each of the conductive layer and the dielectric layer further comprises: a binder resin; Epoxy resin; and curing agent. The anisotropic conductive film according to claim 1, wherein the anisotropic conductive film is used in a glass flip chip (COG) mounting method. A connection structure comprising: a first connection member including a first electrode; a second connection member including a second electrode; and an anisotropic conductive film disposed on the first connection member and the first Between the two connecting members to connect the first electrode to the second electrode, the anisotropic conductive film is an anisotropic according to any one of claims 1 to 14. Conductive film.