KR102744320B1 - Anisopitropic conductive composition and manufacturing method of the same - Google Patents

Abstract

The anisotropic conductive film according to the present invention is
A metal precursor comprising a metal ion providing electrical conductivity;
A curable resin comprising a curable polymer;
A phase separation inducing agent that induces phase separation between the metal reduced from the metal ion and the curable resin; and
It is characterized by including a flow control agent that shortens the curing time and controls flowability.

Description

{Anisopitropic conductive composition and manufacturing method of the same}

The present invention relates to a composition for manufacturing an anisotropic conductive film, an anisotropic conductive film, an anisotropic conductive connection method, and an anisotropic conductive connection structure, and more specifically, to a composition for manufacturing an anisotropic conductive film, an anisotropic conductive film, an anisotropic conductive connection method, and an anisotropic conductive connection structure for bonding and electrically connecting an electrode of a substrate and an electrode of a chip.

The anisotropic conductive film composition is used for various purposes in the manufacture and assembly of semiconductor packages and microelectronic devices. For example, it is used as an electrical connection film for bonding an integrated circuit chip to a substrate, or as a connection film for bonding a circuit assembly to a printed circuit board.

More specifically, the anisotropic conductive film (ACP) can be used for bonding formation of various electronic hardware, including chip-on glass assembly (COG assembly), flip chip on flex assembly, non-contact smart card module assembly, and flip chip die attach on a flexible substrate or a rigid substrate.

Recently, micro LED (Light-emitting diode), also called micro light-emitting diode, refers to an ultra-small LED with a side size of less than 100㎛, and is one of the important technologies for implementing flat panel display technology.

Micro LEDs have the advantages of superior energy efficiency and optical efficiency compared to existing LEDs, low heat generation per unit area, and can implement very small pixels, so they have high potential for use in ultra-small displays and precision medical devices in addition to lighting. An anisotropic conductive film (ACF) is used to attach these micro LEDs to electrodes on a substrate.

Since the size of the micro LED used in the 4K (3840 * 2160) flat panel display was at least 50*20㎛ or more, the bonding process using ACF to attach the electrode was possible. However, in order to implement high-definition resolution of 8K or higher, the size of the micro LED must be reduced to 30*20㎛.

Therefore, when used for electrical bonding of minute elements such as micro LEDs, since the conductive particles used in conventional ACFs are very large, with a diameter in the range of about 3 to 10 ㎛, bonding small micro LED chips is technically problematic. That is, in the case of micro LED chips for high-definition implementation, since the spacing between electrodes is less than 30 ㎛ (or pitch), it is very difficult to bond using a method using an ACF film.

Republic of Korea Patent No. 10-1462658 (Registration date 2014.11.11)

The first aspect of the present invention has been proposed to overcome the above-mentioned problems, and is to provide a composition for manufacturing an anisotropic conductive film which enables bonding even at a fine pitch of 30 ㎛ or less, and has an anisotropic conductive property, that is, electricity is not conducted along the X and Y axes but only along the Z axis, and does not contain conductive particles.

The second aspect of the present invention is to overcome the above-mentioned problem by providing an anisotropic conductive film having a sintered body in which metal particles are reduced in an electrically connecting direction using the composition for manufacturing an anisotropic conductive film as described above.

The third aspect of the present invention is to overcome the above-mentioned problem by providing an anisotropic connection structure having a sintered body in which metal particles are reduced in an electrically connecting direction using the above-mentioned anisotropic conductive film.

The anisotropic conductive film according to the present invention has the following characteristics:

The anisotropic conductive film includes a metal precursor including a metal ion providing electrical conductivity, a curable resin including a curable polymer, a phase separation inducing agent that induces phase separation of the metal reduced from the metal ion and the curable resin, and a flow control agent that shortens the curing time and controls flowability.

The anisotropic challenge film is partially cured by the first heating during manufacturing, enabling it to be freestanding.

When the anisotropic conductive film is subjected to a second heating at a temperature higher than the first heating temperature after being manufactured, the metal particles in which the metal ions are reduced are sintered to form a sintered body.

When the anisotropic conductive film is cured between the first electrode and the second electrode, a conductive path is formed in the Z-axis direction, which is the direction in which the first and second electrodes face each other, and no conductive path is formed in the X-axis and Y-axis directions, which are each perpendicular to the Z-axis direction.

The anisotropic conductive film is formed by a plurality of sintered bodies grown in the Z-axis direction by reduction of metal ions to electrically connect the first electrode and the second electrode.

The anisotropic challenge film contains an acrylic polymer resin having a molecular weight of 10,000 to 1,100,000 as a flow control agent.

The anisotropic conductive film contains an acrylic polymer resin containing methacrylic as a flow control agent and having a glass transition temperature (Tg) of -20 to 110°C.

The anisotropic conductive film further comprises nanoparticles in an amount of 5 to 15 parts by weight per 60 parts by weight of the metal conductive precursor.

The anisotropic conductive film comprises one selected from the group consisting of silver (Ag), gold (Au), indium (In), copper (Cu), indium tin oxide (ITO), palladium, platinum, nickel, and iridium as nanoparticles.

The anisotropic challenge film has nanoparticles with a size of 0.01 to 5.0 ㎛.

The method for manufacturing an anisotropic conductive film according to the present invention has the following characteristics:

A method for manufacturing an anisotropic conductive film includes a step of providing a release film that can easily peel off a coated composition to form a film, a step of applying a composition for manufacturing an anisotropic conductive material, which includes a curable resin, a metal precursor in which a metal ion is dissolved in a liquid phase in the form of a metal salt, and a phase separation inducer that induces phase separation of a metal reduced from the metal ion and the curable resin, in a desired size on the release film.

The method for manufacturing an anisotropic conductive film includes a heating step of applying heat to a coated film to enable free-standing.

The method for manufacturing an anisotropic conductive film further includes a peeling step of peeling a coating from a release film after the heating step to form an anisotropic conductive film.

In the method for manufacturing an anisotropic conductive film, the thickness of the film is set to 30 to 200 um in the composition application step.

In the method for manufacturing an anisotropic conductive film, the composition for manufacturing an anisotropic conductive material additionally includes a flow control agent that shortens the curing time and controls flowability.

A composition for manufacturing an anisotropic conductive material in a method for manufacturing an anisotropic conductive film additionally contains a solvent and has a viscosity of 5 to 10,000 cP at 25°C.

Accordingly, the present invention can be applied to various connection structures requiring various anisotropic challenge electrical connections. In particular, it can be preferably applied to connections of micro LEDs, chip on glass (COG), chip on film (COF), film on board (FOB) of FPD (flat panel display), and connector replacement connections (connections between rigid substrates and film materials, and between film materials and film materials).

The composition for manufacturing an anisotropic conductive film according to the present invention does not contain metal particles therein and thus can be applied to microelectrodes. Thus, even when applied between electrodes, electricity does not flow in the x and y directions but only in the z direction (i.e., between the electrodes of the substrate and the electrodes of the chip), thereby having the effect of allowing electricity to flow in a desired direction without causing a short circuit between the electrodes.

The anisotropic conductive film according to the present invention has a sintered body that is electrically conductive in only one direction by using a metal component that is reduced and sintered by light or heat inside. Therefore, even if it is installed across adjacent electrodes, short circuits between the electrodes do not occur in the other direction, so there is an effect that anisotropic conductive connection between microelectrodes can be efficiently achieved.

Fig. 1 (a) is a conceptual diagram explaining a connection structure according to the present embodiment.
FIG. 2 is a schematic diagram explaining a mechanism in which a region where a sintered body is located and a region where a polymer is located are hybridized with each other and have an anisotropic structure due to reduction and sintering of metal particles and hardening of a curable resin during heat or laser curing according to the present embodiment.
Figure 3 is an experimental photograph showing the resistance measurement of an anisotropic conductive film manufactured with the composition of Example 1.
Figure 4 is a photograph showing the resistance measurement location.
Figure 5 is a resistance graph between an ITO substrate and a COF film.
Figure 6 is a resistance graph between a glass substrate and a COF film.
Figure 7 is an experimental photograph showing the resistance measurement between the electrode and the conductive substrate after thermal curing of the anisotropic conductive film manufactured with the composition of Example 2.
Figure 8 is an experimental photograph showing the resistance measurement between the electrode and the insulating substrate after thermal curing of the anisotropic conductive film manufactured with the composition of Example 2.
Figure 9 is a cross-sectional view of a laser hardening device.
Figure 10 is an electron microscope photograph of the bonding material portion taken by an electron microscope after bonding the electrodes in Experimental Example 3.
Figure 11 is an EDS analysis photograph of a sintered body formed between electrodes in Experimental Example 3.
Figure 12 is a process diagram explaining a process of attaching a micro LED electrode to a micro LED substrate using an anisotropic conductive film.
Figure 13 is an experimental photograph showing the lighting of micro LEDs.
Figures 14 and 15 are electron microscope photographs of the area where the anisotropic conductive film is cured to connect the electrodes.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. However, the spirit of the present invention is not limited to the presented embodiments, and those skilled in the art who understand the spirit of the present invention will be able to easily propose other regressive inventions or other embodiments included within the scope of the spirit of the present invention by adding, changing, deleting, etc. other components within the scope of the same spirit, but this will also be considered to be included within the scope of the spirit of the present invention.

In addition, components having the same function within the same scope of the same idea shown in the drawings of the embodiment are described using the same reference numerals.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

<Aspect 1>

A first embodiment of a composition for manufacturing an anisotropic conductive material according to the first aspect of the present invention comprises a metal precursor, a phase separation inducer, a curable resin, curing agents for curing the curable resin, a flow control agent, and a solvent.

The metal precursor is a material before being reduced to a metal filler having conductivity in the anisotropic conductive composition. The metal precursor may be a compound including a metal hydride, a metal hydroxide, a metal sulfur oxide, a metal nitrate, a metal halide, a metal complex compound, or a combination thereof.

At this time, the metal precursor may include one or more metals or alloys thereof having high electrical conductivity, such as silver (Ag), copper (Cu), gold (Au), bismuth, indium, palladium, platinum, nickel, and iridium. It is preferable to include silver (Ag), which is easily reduced, has high electrical conductivity after reduction, and is stable.

In addition, the anions for forming the metal precursor are hydroxide ion, carboxylic ion, acetate ion, propionate ion, acetylacetonate ion, 2,2,6,6-tetramethyl-3,5-heptanedionate ion, methoxide ion, sec-butoxide ion, t-butoxide ion, n-propoxide ion, ipropoxide ion, ethoxide ion, phosphate ion, alkylphosphonate ion, nitrate ion, perchlorate ion, sulfate ion, It is preferred that the anion comprises at least one or a combination of anions selected from the group consisting of alkylsulfonate ion, phenoxide ion, bromide ion, iodide ion, and chloride ion.

A phase separation inducer is a substance that induces phase separation between a reduced metal and a hardened polymer. It is a substance that causes phase separation between the reduced metal and the hardened polymer when the metal precursor is reduced by heat or light (laser) as described later. In other words, the metal ion in the metal precursor state is sintered while being reduced, and at this time, it phase separates from the polymer.

It is presumed that the phase separation inducer contains both hydrophilic and lipophilic groups in the molecule, and thus the hydrophilic groups induce phase separation by surrounding the reduced conductive metal particle mass (hereinafter referred to as the sintered body) on the surface, and the lipophilic groups come into contact with the polymer.

At this time, it is preferable that the number of carbon atoms in the lipophilic group is 5 to 25, and the hydrophilic group includes a carboxyl group (-COOH) or an amine group (- NH).

Specifically, the phase separation inducer is a compound containing a carboxyl group, and at least one fatty acid selected from the group consisting of caprylic acid, pelargonic acid, caproic acid, undecanic acid, lauric acid, myristic acid, behenic acid, palmitic acid, lignoceric acid, stearic acid, eicosanoic acid, and oleic acid or a combination thereof may be used.

Among the phase separation inducers, compounds containing amines may be used, for example, at least one selected from the group consisting of hexylamine, heptylamine, octylamine, oleylamine, decylamine, dodecylamine, 2-ethylhexylamine, and 1,3-dimethyl-n-butylamine, or a combination thereof.

At this time, the phase separation inducer induces phase separation by surrounding the reduced conductive metal particle mass (hereinafter referred to as a sintered body) on the surface with the hydrophilic group, carboxyl group or amine group, and by contacting the polymer with the lipophilic group, alkyl group.

When the anisotropic conductive composition is heated by heat or laser in a state where the metal and polymer are phase separated to become a cured product, the cured product forms a plurality of sintered bodies through reduction of metal ions, and the metal sintered body becomes conductive because it is rich in metal. In addition, the area excluding the sintered body becomes non-conductive because the curable resin is formed into a hardened polymer.

At this time, the cured product is formed by reducing metal ions, and a plurality of sintered bodies grow in the Z-axis direction to electrically connect the first electrode and the second electrode, and the plurality of sintered bodies are not connected to each other in the X and Y-axis directions.

By this method of inducing phase separation, the X and Y axes do not form conductive paths, and only the Z-axis direction becomes a conductive path through which electricity can flow. At this time, the Z-axis is, for example, the direction in which the first electrode and the second electrode face each other, and the X and Y-axis directions are directions perpendicular to the Z-axis direction.

The curable resin is a polymer resin that can be polymerized by radicals, and a resin such as an epoxy resin can be used. The epoxy resin that can be used includes a bisphenol A type epoxy resin, a substituted epoxy resin, a linear aliphatic epoxy resin, a cresol novolac type epoxy resin, a biphenyl type epoxy resin, a heterocyclic epoxy resin, a halogenated epoxy resin, and a material containing two or more epoxy groups per molecule. In addition, two or more types of the above-mentioned epoxy resins can be used in combination.

In addition, an acrylic resin can be used as the curable resin, and at this time, a monomer for curing, (meth)acrylate, is a monomer or oligomer having one or more functional groups, and one or more selected from urethane acrylate, epoxy acrylate, cresol novolac acrylate, phenol novolac acrylate, phosphoric acid acrylate, etc. having one or more reactive functional groups and less than 20 can be used.

Preferred examples of acrylate monomers include neopentylglycol mono(meth)acrylate, 1,6-hexanediol mono(meth)acrylate, pentaerythritol penta(meth)acrylate, dipentaerythritol penta(meth)acrylate, glycerin di(meth)acrylate, tetrahydrofurfuryl(meth)acrylate, isodecyl(meth)acrylate, 2-(2-ethoxyethoxy)ethyl(meth)acrylate, stearyl(meth)acrylate, lauryl(meth)acrylate, 2-phenoxyethyl(meth)acrylate, isobornyl(meth)acrylate, A monomer selected from the group consisting of tridecyl (meth)acrylate, ethoxylated nonylphenolacrylate, ethylene glycol di(meth)acrylate, ethoxy added bisphenol-AD(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, phenoxy tetraethylene glycol (meth)acrylate, 2-methacryloyloxyethyl phosphate, 2-methacryloyloxyethyl phosphate, dimethylol tricyclodecane di(meth)acrylate, dipentaerythritol hexaacrylate, trimethylopropanebenzoate acrylate, and mixtures thereof. The content of the (meth)acrylate monomer is preferably about 5 to 50 wt%.

The curing agent is a substance that cures the curable resin with heat or light, and one or more amine or phosphine compounds can be used. For example, amine curing agents include 2-methyl imidazole, 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, and 2-phenyl-4-methylimidazole; tertiary amine compounds include triethylamine, benzyldimethylamine, methylbenzyldimethylamine, 2-(dimethylaminomethyl)phenol, and 2,4,6-tris(dimethylaminomethyl)phenol.

Additionally, the phosphine compounds may be triethylphosphine, tributylphosphine, 1,8-diazabicyclo(5,4,0)undecene-7; or as organic phosphine compounds, triphenylphosphine, trimethylphosphine, triethylphosphine, tributylphosphine, tri(p-methylphenyl)phosphine (Tris(4-methoxyphenyl)phosphine), tri(nonylphenyl)phosphine may be used.

The curing agent for curing the acrylic resin is a substance that cures the curable resin with heat or light, and is preferably an oil-soluble curing agent or a redox curing agent such as an organic peroxide such as lauryl peroxide, benzoyl peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, or t-butyl hydroperoxide.

The flow control agent is a component included to control the flow of the conductive agent and to achieve rapid curing of the composition. The acrylic polymer resin having a molecular weight of 10,000 to 1,100,000 and a glass transition temperature (Tg) of -20 to 110°C is preferable, and the acrylic polymer resin containing methacrylic is preferable.

When manufacturing a conductive material as a freestanding conductive material (e.g., film), if the molecular weight is less than 10,000, it is difficult to manufacture it by forming a film during the first heating, and when pressing during the second heating, it flows too easily due to the high temperature and high pressure, so the resin comes out too easily, the resistance increases, and the adhesive strength is greatly reduced. If it is more than 1,100,000, the film becomes too brittle and breaks easily, and the tackiness (stickiness) is too low, so the film and COF, TCP, etc. do not stick together during pressurization, which increases the probability of defects.

At this time, the first heating refers to heating that enables free-standing curing from the composition without reducing the internal metal ions, and the second heating refers to heating that reduces the internal metal ions to form a sintered body.

In addition, since the aforementioned flow control agent has an initial electrical connection resistance value that cannot be obtained with a conventional ACF and a high Tg of the acrylic rubber itself when connected to the electrode of a COF (chip on flexible printed circuit) and the ITO or Ti/Al/Ti electrode section, it is possible to obtain sufficient connection reliability by having heat and moisture resistance.

The solvent is for dissolving the above-mentioned components, and the solvent may be used without limitation, but may include tetrahydrofuran (THF), alcohol solvents, ether solvents, sulfide solvents, toluene solvents, xylene solvents, benzene solvents, alkane solvents, oxane solvents, amine solvents, polyol solvents, or diketone, amino alcohol, polyamine, ethanol amine, diethylnol amine, ethane thiol, propane thiol, butane thiol, pentane thiol, hexane thiol, heptane thiol, It is preferable to use a solvent comprising at least one solvent selected from the group consisting of octane thiol, nonane thiol, decane thiol, and undecane thiol, or a combination thereof.

In the above-described composition, it is preferable that the metal precursor is contained in an amount of 60 parts by weight, the phase separation inducer in an amount of 5 to 15 parts by weight, the curable resin in an amount of 3 to 8 parts by weight, the curing agent in an amount of 3 to 8 parts by weight, and the solvent in an amount of 15 to 25 parts by weight.

If the phase separation inducer exceeds the above range compared to the metal precursor, there is a problem of increased electrical resistance, and if it is below the above range, there is a problem of no phase separation induction.

In addition, if the amount of curable resin used is less than the range, there is a possibility that the adhesion will be poor, and if the amount of curable resin used is more than the range, there is a problem that the electrical resistance between the micro LED and the substrate electrode increases.

In addition, if the amount of the hardener is less than the range, poor adhesion may occur due to insufficient curing of the curable resin, and if the amount is more than the range, the curing speed of the curable resin may become too fast, making it difficult to obtain sufficient electrical conductivity, or the composition may become cured before transfer occurs.

Therefore, within the above-mentioned range, the composition may have a 5B adhesion test scale of ISO 2409, a continuous printability of >7 days, and a laser curing characteristic that is ultra-fast curing of 30 seconds or less, preferably 10 seconds or less, upon laser curing.

Meanwhile, when curing the composition with a laser, a wavelength of 760 nm to 4900 nm can be used, and IR having a wavelength of 1000 nm to 4900 nm is particularly preferable. This is because when the wavelength is outside the above range, damage may occur to electronic components when curing with a laser.

Even when reducing a metal precursor with a laser and sintering, both materials that are curable with heat or light are possible. The reason why a curable resin that is curable with heat is possible even when curing with a laser is because heat is generated in the electrode by the laser, and the heat generated at that time provides the heat necessary for curing the curable resin.

In this aspect, the composition for manufacturing an anisotropic conductive film is sintered by the following mechanism, and a sintered body in which a metal precursor is reduced is formed, thereby having conductivity even without conductive particles.

(Formula 1)

Example B of an anisotropic conductive composition according to the first aspect of the present invention comprises a metal precursor, a phase separation inducer, a curable resin, curing agents for curing the curable resin, a flow control agent, a solvent, and conductive particles.

That is, compared to Embodiment A, Embodiment B further includes conductive particles. The conductive particles may be selected from the group consisting of silver (Ag), gold (Au), indium (In), copper (Cu), indium tin oxide (ITO), palladium, platinum, nickel, and iridium, and nanoparticles having a size in the range of 0.01 to 5.0 μm may be used.

It is preferable that the conductive particles are included in an amount of 5 to 15 parts by weight per 60 parts by weight of the metal conductive precursor. Thus, by adding a small amount of the conductive particles, the electrical conductivity can be further improved in addition to the sintered body having electrical conductivity.

Conductive materials that can be manufactured from the composition for manufacturing anisotropic conductive materials may include anisotropic conductive films (ACFs), anisotropic conductive tapes (ACTs), anisotropic conductive adhesives (ACAs), anisotropic conductive pastes (ACPs), etc.

<Second side>

The second aspect of the present invention is a method for manufacturing an anisotropic conductive film. The manufacturing of an anisotropic conductive film includes a release film providing step, a composition applying step, and a heating step.

The release film providing step is a step of providing a release film that can easily peel off the applied composition and form a film. The release film is not limited in type as long as it is a common film used in the art, and for example, PET film can be used.

The composition application step is a step of applying the composition of the first side to a release film in a desired size. The thickness of the coating film at the time of application is 30 to 200 um, preferably 40 to 150 um.

It includes a metal precursor, a phase separation inducer, a curable resin, curing agents for curing the curable resin, a flow control agent, and a solvent.

The metal precursor is dissolved in a liquid phase in the form of a metal salt when applied, but is reduced by heat or light between the electrodes to function as a conductive metal. At this time, the reduced conductive metal forms a particle mass (hereinafter referred to as a sintered body) and acquires metallic conductivity. The metal precursor is not reduced in the anisotropic conductive film state before being heated between the electrodes.

When the phase separation inducer is cured by heat or light, it causes the curable resin and the reducing metal precursor to phase separate from each other, so that the areas where each metal and resin are located are distinct in the applied state.

At this time, the reduced metal within the applied film forms at least one sintered body, and when it is called a polymer region in which a curable resin is distributed, the sintered body is distributed within the polymer.

The curable resin and the curing agent are resins suitable for general heat curing or photocuring, and are cured while forming a polymer region that is separated from the metal by a phase separation inducer during heat or photocuring.

The flow control agent is a component included to control the flowability for rapid curing of the composition and film formation, and is preferably an acrylic polymer resin having a molecular weight of 10,000 to 1,100,000, a glass transition temperature (Tg) of -20 to 110°C, and containing methacrylic.

The solvent is a substance that dissolves the resin, and the viscosity of the composition after dissolution is preferably 5 to 10,000 cP, more preferably 10 to 2,000 cP, at 25°C.

In the composition application step, the application of the composition may be performed using one method selected from the group consisting of screen printing, inkjet, doctor blade, slot die, dispenser, eHD printing, spin coating, and pad printing, depending on the purpose of the application product being used. A description of each method is as follows.

Screen printing is a printing method that transfers ink to a substrate through a specially designed mesh screen, and has the advantage of being able to print thick paint on various substrates.

Inkjet printing is a digital printing method that sprays fine ink droplets onto a substrate through a nozzle. It has high resolution and fast production speed, and is also used for flexible substrates and semiconductor devices.

A doctor blade is a sharp bladed tool used in the screen printing process to evenly spread ink and remove excess, improving the quality of electronic printing by increasing the thickness and consistency of the ink.

Slot die is a method of coating a substrate with paint or adhesive at a certain thickness, and is used in the manufacture of electronic components and elements due to its precise thickness control and high production efficiency.

A dispenser is a device that precisely places a small amount of ink, adhesive, or paint on a substrate, and is used for various electronic printing tasks such as bonding electronic components and placing elements.

eHD printing is a technology that uses electric fields to enable high-precision and high-resolution printing, and is used for fine electronic components and organic light-emitting diode (OLED) displays.

Spin coating is a process of forming a coating of a certain thickness by dropping a liquid or gel-like material onto a high-speed rotating substrate. It is used in various electronic devices and semiconductor processes to create an even, thin coating.

Pad printing is a printing technology that uses a soft silicone pad to transfer ink from a printing plate to a substrate with a complex shape or surface. It can also print on electronic components with curved or irregular surfaces, and is used in the manufacture of various electronic products.

The heating step is the first heating step described above, and is a step of applying heat to the coating film applied in the composition application step. By applying heat to the coating film, the applied composition hardens to a certain degree and can be peeled off as a film. The heating temperature is preferably 60 to 100°C. At the heating temperature, which is a temperature suitable for film formation, the metal precursor in the coating film applied in this heating step is not reduced to a sintered body, and the applied composition has a free-standing property.

The peeling step is a step of forming an anisotropic conductive film by peeling the coating from the release film. The anisotropic conductive film manufactured in the peeling step is still in an unsintered state in the metal precursor in the heating step, and when it is later placed between electrodes and a laser or heat is applied, the metal precursor is reduced and sintered, thereby conducting electricity in one direction.

<Third Aspect>

After the peeling step, the peeled connecting material becomes an anisotropic conductive film that conducts electricity in only one direction.

An anisotropic conductive film manufactured according to the present invention is manufactured from a composition including a metal precursor capable of forming a sintered body having conductivity by being reduced by heat or laser while the film is formed by a flow control agent, a phase separation inducer, a curable resin, and curing agents for curing the curable resin.

Accordingly, when the anisotropic conductive film is subjected to a second heating temperature higher than the first heating temperature applied during the manufacturing process of the anisotropic conductive film of the second aspect described above after being manufactured, the metal ions inside the film are reduced to become metal particles, and the metal particles are sintered to form a sintered body.

The second heating is preferably 100 to 300°C. Below the above range, it is difficult to form a sintered body, and if it exceeds the above range, the process temperature is high, causing problems such as heat damage to the substrate or base material.

At this time, the sintered body grows in one direction, and the area surrounding the sintered body is a region where the polymer is hardened, so a conductive path is formed through which electricity can only move in the direction in which the sintered body grows.

That is, when the anisotropic conductive film is inserted between the first electrode and the second electrode of the electronic component and is cured by the second heating, a conductive path is formed by the sintered body in the Z-axis direction, which is the direction in which the first and second electrodes face each other, so that electricity flows, and no conductive path is formed in the X-axis and Y-axis directions, which are respectively perpendicular to the Z-axis direction.

At this time, the anisotropic conductive film may further include nanoparticles in an amount of 5 to 15 parts by weight per 60 parts by weight of the metal precursor.

It is preferable that the nanoparticles be one selected from the group consisting of silver (Ag), gold (Au), indium (In), copper (Cu), ITO (indium tin oxide), palladium, platinum, nickel, and iridium, or an alloy thereof.

Additionally, it is preferable that the nanoparticles be 0.01 to 5.0 ㎛.

<Aspect 4>

The fourth aspect of the present invention is a connection structure using an anisotropic conductive film.

Fig. 1 (a) is a conceptual diagram explaining a connection structure according to the present embodiment, and the connection structure according to the present embodiment includes a first electrode (20), a second electrode (30), and a connection material (70) that electrically connects the first electrode (20) and the second electrode (30).

The first electrode (20) is an electrode for electrical connection formed on a device or a flexible substrate, and the material of the electrode is not limited, but can be used as a transparent electrode, an opaque electrode, etc., and for example, can be used as an ITO electrode, a Ti/AL/Ti electrode.

The second electrode (30) is an electrode for electrical connection with the first electrode (20), and may be, for example, a substrate having a fine-pitch wiring electrode or a backplane substrate for attaching the electrode of a micro LED chip. The second electrode (30) is provided at a position facing the first electrode (20), and may be an electrode having a laminated structure of copper, gold (Au), or molybdenum-aluminum-molybdenum.

At this time, the first electrode (20) and the second electrode (30) are respectively opposed, and the gap between the first electrode (20) and the second electrode (30) is preferably 10 nm to 10 μm, preferably 10 nm to 1000 nm, preferably 100 to 450 nm, and more preferably 140 to 440 nm. If the gap exceeds the above range, there is a problem that the contact resistance increases. At this time, the width of each electrode is 1 to 1000 μm, preferably 3 to 80 μm.

The connecting material (70) is a material for electrically connecting the first electrode (20) and the second electrode (30), and is an anisotropic conductive connecting material that allows electricity to flow only in the direction of connection between the first electrode (20) and the second electrode (30) and does not allow electricity to flow in a direction other than the direction of connection between the first electrode (20) and the second electrode (30).

At this time, the connecting material is positioned between the first electrode (20) and the second electrode (30) to physically and electrically connect them, and when cured, the first electrode (20) and the second electrode (30) are formed by curing the anisotropic conductive composition film placed between them while being heated and pressurized.

The anisotropic conductive film is a film manufactured from a composition including a metal precursor, a phase separation inducer, a curable resin, a curing agent, a curable resin, a flow control agent, and a solvent for dissolving the curing agent.

An anisotropic conductive film between the first electrode and the second electrode has a structure in which a sintered body, in which a metal ion derived from a metal precursor is reduced when cured with a laser or heat to form a conductive path that electrically connects the first electrode and the second electrode, is separated from a polymer region where a polymer formed by curing a curable resin is located. At this time, a plurality of regions where the sintered body is located and regions where the polymer is located are hybridized with each other.

That is, the metal precursor exists as a metal ion in the ink state, and in the process of reducing the metal ion of the precursor by heat or laser, the metal is reduced to a metal on the surface of the electrode portion of the chip and substrate, forming a seed layer, and metal particles gradually grow centered on the seed layer, and simultaneously with the growth of the metal particles, they are separated into a metal region and a binder region by a phase-separation inducer, and thereafter, the metal is sintered and the binder is hardened in each different region.

Fig. 1 (b) is a conceptual diagram explaining a connection structure according to another embodiment, which is a connection structure in which two electrodes have two opposing electrodes. The connection structure according to this embodiment includes a third electrode (120a), a fourth electrode (120b), a fifth electrode (130a), a sixth electrode (130b), and a connection material (170) electrically connecting the third electrode to the fifth electrode and the fourth electrode to the sixth electrode.

The third electrode (120a) and the fourth electrode (120b) are electrodes for electrical connection formed on the substrate, and may be, for example, a backplane substrate for attaching micro LEDs, and the fifth electrode is provided at a position opposite the third electrode, such that the electrode opposite the third electrode is referred to as the fifth electrode, and the electrode opposite the fourth electrode is referred to as the sixth electrode, and may be an electrode having a layered structure of molybdenum-aluminum-molybdenum.

The fifth electrode (130a) and the sixth electrode (130b) are electrodes for electrical connection formed in an element formed in an electronic component, and may be, for example, a semiconductor chip or a micro LED chip. In the case of a micro LED chip, the electrode may be gold, and one electronic component may have the fifth electrode (130a) and the sixth electrode (130b) as two electrodes, an anode and a cathode.

At this time, the gap between the third electrode and the fourth electrode (the fifth electrode and the sixth electrode) is 1 to 50 ㎛, preferably 3 to 50 ㎛, and the width of each electrode is 1 to 1000 ㎛ and 3 to 80 ㎛.

Meanwhile, the spacing between the third electrode and the fifth electrode (the fourth electrode and the sixth electrode) is preferably 10 nm to 10 μm, preferably 10 nm to 1000 nm, preferably 100 to 450 nm, and more preferably 140 to 440 nm. If the spacing exceeds the above range, there is a problem that the contact resistance increases.

The connecting material is a material for electrically connecting the third electrode and the fifth electrode (the fourth electrode and the sixth electrode), and is an anisotropic conductive connecting material in which electricity flows only in the connection direction between the third electrode and the fifth electrode and the fourth electrode and the sixth electrode, and does not flow in a direction other than the connection direction between the third electrode and the fifth electrode (the fourth electrode and the sixth electrode).

Accordingly, even if the heterogeneous conductive composition is connected to the third electrode and the fourth electrode to form a film across them, electricity does not flow in the connection direction of the third electrode and the fourth electrode, so a short circuit does not occur between the third electrode and the fourth electrode.

At this time, the connecting material is positioned between the third electrode and the fifth electrode (the fourth electrode and the sixth electrode) to physically and electrically connect them, and when cured, the anisotropic conductive composition film between the first electrode and the second electrode is cured by laser and heat.

The anisotropic conductive film includes a metal precursor, a phase separation inducer, a curable resin, a curing agent for curing the curable resin, and a solvent for dissolving the curable resin and the curing agent.

The cured product of the anisotropic conductive film has a structure in which a sintered body formed by reduction of metal ions derived from a metal precursor is distributed separately without belonging to a polymer region formed by curing a curable resin. At this time, the sintered body region and the polymer region are distributed separately from each other.

For example, if the electronic component is a micro LED, and the fifth and sixth electrodes of the micro LED are respectively connected to the third and fourth electrodes of the substrate, the LED will light up without a short circuit.

FIG. 2 is a schematic diagram explaining a mechanism in which a region where a sintered body is located and a region where a polymer is located are hybridized with each other and have an anisotropic structure due to reduction and sintering of metal particles and hardening of a curable resin during heat or laser curing according to the present embodiment.

Accordingly, when the anisotropic conductive film manufactured by the present embodiment is positioned between electrodes and cured, a metal sintered body initially begins to form on each surface of the LED chip electrode (120a) and the electrode (110) of the substrate. As sintering progresses, the metal sintered body grows more and more based on the metal sintered body formed on the surface, and the LED chip electrode (120a) and the electrode (110) of the substrate are connected to each other. (This is confirmed in FIGS. 24 and 25 described below.) That is, the metal sintered body is formed by growing the metal sintered bodies formed on each surface of the LED chip electrode (120a) and the electrode (110) of the substrate and joining them to each other.

In the above description, the number of electrodes has been limited for convenience of explanation, but those skilled in the art will recognize that the same can be applied to a connection structure composed of N lower electrodes and N upper electrodes facing them.

<Example>

<Manufacturing Example 1> Manufacturing of flow control agent

2-Ethylhexylacrylate and n-Buthylacrylate were purchased from "Junsei Chemical", vinyl acetate (VAc) used as a copolymer was purchased from "Kanto Chemical", 1-vinyl-2-pyrrolidinone (NVP) was purchased from "Aldrich Chemical", and functional group-containing monomers such as acrylic acid (AA), glycidyl methacrylate (GMA), and 2-hydroxyethyl methacrylate (MEMA) were purchased from "Junsei Chemical". Benzoyl peroxide (BPO) as initiator was manufactured by Youngwoo Chemical Co., Ltd. and α,α'-azobis isobutyronitrile (AIBN) was manufactured by Junsei Chemical Co., Ltd. The solvents were ethyl acetate, methanol, and toluene, all grade 1 reagents manufactured by Daewon Chemical Co., Ltd. Each monomer was placed into a 2 L four-necked flask equipped with a stirrer, thermometer, and reflux condenser according to the compositions in the table below. The entire monomer was placed, followed by the solvent. The initiator was dissolved in the solution and solvent (EAc: TOL = 7:3) and placed. As soon as the addition was completed, polymerization was performed at 70°C for 8 hours at a stirring speed of 200 rpm. When the reaction was complete, the solid content was adjusted to 40% using toluene, cooled with cooling water, and Tg was measured.

The Tg of the polymer was measured using a DSC-550 model from Differential Scanning Calorimeter (DSC) Instrument Specialists. The measurement method was as follows: first heating from room temperature to 100°C at a heating rate of 10°C/min (1 run), then cooling to -100°C using liquid nitrogen, and the Tg was investigated as the midpoint of the tangent line during the second heating (2nd run).

<Manufacturing examples 2 to 5> Manufacturing of flow control agent

Manufacturing Examples 2 to 5 were manufactured as in Manufacturing Example 1 described above, and their compositions are summarized in Table 1.

　
Flow control agent
Manufacturing example 1
Manufacturing example 2
Manufacturing example 3
Manufacturing example 4
Manufacturing example 5
Acrylic monomer
2-Ethylhexylacrylate
10
10
20
10
　
n-Butylacrylate
5
5
　
5
　
Vinyl Acetate
5
5
　
5
　
Acrylic acid (AA) as a monomer
10
10
10
10
30
Glycidyl Methacrylate
5
5
5
5
5
2-Hydroxyethyl Methacrylate
5
　
　
5
　
1-Vinyl-2-Pyrrolidinone
　
5
5
　
15
Initiator
The initiator is benzoyl peroxide (BPO).
20
20
20
　
10
α,α'-azobis isobutyronitrile (AIBN)
　
　
　
20
　
solvent
Ethyl Acetate
20
20
20
20
20
Methanol,
　
　
　
　
20
Toluene
20
20
20
20

Total
　
100
100
100
100
100
Tg(℃)
　
18
20
58
45
110

<Examples 1 to 10>: Composition for film production

　
ACA film composition
Example-1
Example-2
Example-3
Example-4
Example 5
Example-6
Example-7
Example-8
Example-9
Example-10
Metal precursor
　
30
30
30
30
30
30
30
30
30
30
Acrylic adhesive
Manufacturing example 1
30
　
　
　
　
30
30
30
30
30
Manufacturing example 2
　
30
　
　
　
　
　
　
　
　
Manufacturing example 3
　
　
30
　
　
　
　
　
　
　
Manufacturing example 4
　
　
　
30
　
　
　
　
　
　
Manufacturing example 5
　
　
　
　
30
　
　
　
　
　
Acrylic
bookbinder
(Adhesion Aid)
Dipentaerythritol penta(meth)acrylate
10
10
10
10
10
　
　
　
　
　
Tetrahydrofurfuryl(meth)acrylate
　
　
　
　
　
10
　
　
　
　
isodecyl(meth)acrylate,
　
　
　
　
　
　
10
　
　
　
Hydroxyethyl acrylate
　
　
　
　
　
　
　
10
　
　
2-Hydroxyethylmethacrylate
　
　
　
　
　
　
　
　
　
　
Acrylic binder hardener
Benzoyl peroxide
5
5
5
5
5
5
5
5
　
　
t-butyl hydroperoxide
　
　
　
　
　
　
　
　
　
　
Epoxy binder (adhesion aid)
YD-114E (KUKDO, Bisphenol-A type liquid epoxy resin)
　
　
　
　
　
　
　
　
10
　
YD-128 (KUKDO, Unmodified Bisphenol-A based Liquid Epoxy Resin)
　
　
　
　
　
　
　
　
　
10
YDF-170 (KUKDO, BISPHENOL-F TYPE EPOXY RESIN)
　
　
　
　
　
　
　
　
　
　
Epoxy binder hardener
2-Phenyl-4-methylimidazole (aldrich)
　
　
　
　
　
　
　
　
5
　
2,4,6-Tris(dimethylaminomethyl)phenol(aldrich)
　
　
　
　
　
　
　
　
　
5
Metal particles
Ag Nano particle dispersion (20nm, aldrich, 730793)
　
　
　
　
　
　
　
　
　
　
Cu Nano particle dispersion (WiNEL, 10nm)
　
　
　
　
　
　
　
　
　
　
solvent
butyl actetate
15
15
15
15
15
15
15
15
15
15
Toluene
10
10
10
10
10
10
10
10
10
10
Total (wt%)
　
100
100
100
100
100
100
100
100
100
100

<Examples 11 to 13, Comparative Examples 1 to 4>: Composition for film production

　
ACA film composition
Example-11
Example-12
Example-13
Comparative Example-1
Comparative Example-2
Comparative Example-3
Comparative Example-4
Metal precursor
　
30
20
20
　
30
30
30
Acrylic adhesive
Manufacturing example 1
30
　
　
30
　
30
30
Manufacturing example 2
　
30
30
　
　
　
　
Manufacturing example 3
　
　
　
　
　
　
　
Manufacturing example 4
　
　
　
　
　
　
　
Manufacturing example 5
　
　
　
　
　
　
　
Acrylic
bookbinder
(Adhesion Aid)
Dipentaerythritol penta(meth)acrylate
　
10
10
10
40
　
25
Tetrahydrofurfuryl(meth)acrylate
　
　
　
　
　
　
　
isodecyl(meth)acrylate,
　
　
　
　
　
　
　
Hydroxyethyl acrylate
　
　
　
　
　
　
　
2-Hydroxyethylmethacrylate
　
　
　
　
　
　
　
Acrylic binder hardener
Benzoyl peroxide
　
5
5
5
5
　
15
t-butyl hydroperoxide
　
　
　
　
　
　
　
Epoxy binder (adhesion aid)
YD-114E (KUKDO, Bisphenol-A type liquid epoxy resin)
　
　
　
　
　
　
　
YD-128 (KUKDO, Unmodified Bisphenol-A based Liquid Epoxy Resin)
　
　
　
　
　
　
　
YDF-170 (KUKDO, BISPHENOL-F TYPE EPOXY RESIN)
10
　
　
　
　
　
　
Epoxy binder hardener
2-Phenyl-4-methylimidazole (aldrich)
　
　
　
　
　
　
　
2,4,6-Tris(dimethylaminomethyl)phenol(aldrich)
　
　
　
　
　
　
　
Metal particles
Ag Nano particle dispersion (20nm, aldrich, 730793)
5
10
　
30
　
　
　
Cu Nano particle dispersion (WiNEL, 10nm)
　
　
10
　
　
　
　
solvent
butyl actetate
15
15
15
15
15
25
　
Toluene
10
10
10
10
10
15
　
Total (wt%)
　
100
100
100
100
100
100
100

<Experimental example>

<Experimental Example 1> Property Evaluation

The adhesion and connection resistance properties of the film-making compositions of Examples 1 to 13 and Comparative Examples 1 to 4 described above were evaluated, and the results are summarized in Tables 4 and 5.

　
ACA film composition
Example-1
Example-2
Example-3
Example-4
Example 5
Example-6
Example-7
Example-8
Example-9
Example-10
Property Evaluation
Initial adhesion (g/cm, 90° peel strength test)
980
983
941
975
957
1024
976
1094
987
996
Adhesion after reliability evaluation (g/cm,, 85° C. and RH. 85%, 1,000 hr, 90° peel strength test)
1064
1064
1019
1001
968
1067
987
1148
1041
1110
Adhesion after reliability evaluation (g/cm, ─40° C. to 80° C. for 1000 cycles, 90° peel strength test)
1110
1121
1067
1011
994
1084
988
1221
1034
1210
Initial connection resistance (Ω, 2-point probe)
5.8
5.9
6.4
8.4
7.5
6.8
9.1
6.8
8.8
5.6
Connection resistance after reliability evaluation (Ω, 85° C. and RH. 85%, 1,000 hr, 2-point probe)
6.4
6.5
8.4
8.8
8.9
7.4
10.1
8.5
8.6
8.4
Connection resistance after reliability evaluation (Ω, ─40° C. to 80° C. for 1000 cycles, 2-point probe)
6.7
6.1
7.4
7.6
8.8
6.4
8.4
7.4
9.1
9.1

　
ACA film composition
Example-11
Example-12
Example-13
Comparative Example-1
Comparative Example-2
Comparative Example-3
Comparative Example-4
Physical property evaluation
Initial adhesion (g/cm, 90° peel strength test)
1032
987
991
987
Immeasurable
(Not made into a film)
518
Immeasurable
(Not made into a film)
Adhesion after reliability evaluation (g/cm,, 85° C. and RH. 85%, 1,000 hr, 90° peel strength test)
1031
1112
1110
1061
ND
Adhesion after reliability evaluation (g/cm, ─40° C. to 80° C. for 1000 cycles, 90° peel strength test)
1110
1211
1121
1121
ND
Initial connection resistance (Ω, 2-point probe)
6.1
8.9
10.4
1200
5.4
Connection resistance after reliability evaluation (Ω, 85° C. and RH. 85%, 1,000 hr, 2-point probe)
6.8
9.8
11.4
1500
5.5
Connection resistance after reliability evaluation (Ω, ─40° C. to 80° C. for 1000 cycles, 2-point probe)
6.9
9.8
11.5
1500
6.1

<Experimental Example 1> Measurement of conductivity and insulation resistance

An anisotropic conductive film manufactured with the composition of Example 1 was attached to a PI film (COF film) in which the size of the copper electrodes was 8 μm and the spacing (space) between the electrodes was 13 μm. Next, an ITO substrate having a size of 1.5 mm x 12 mm was bonded to the anisotropic conductive film, and bonding was performed over time under the conditions of 230°C and a bonding pressure of 130 MPa using an ACF Bonder (BD-02 Tabletop Heat Bonder (Pulse heater), OHASHI ENGINEERING Co., Ltd.).

As shown in Fig. 4, an anisotropic conductive film according to the present invention is placed between an ITO substrate and a COF film, and the resistance is measured, which is summarized in Table 6 and Fig. 5. After 60 seconds, the resistance is stably measured to be less than 10Ω, and it can be confirmed that the electrode of the COF is electrically connected to the ITO.

Time
(s)
measurement
location
1
2
3
4
5
6
7
8
30
1-2
electrode
28
117
74
10
15
17
15
10
3-4
electrode
55
34
14
12
16
13
17
19
60
1-2
electrode
15
13
10
7
7
6
6
7
3-4
electrode
10
16
10
7
6
6
9
8
90
1-2
electrode
9
15
10
7
6
6
6
5
3-4
electrode
8
9
8
6
5
5
5
5
120
1-2
electrode
8
9
9
6
6
6
6
5
3-4
electrode
7
7
6
6
5
5
5
5
150
1-2
electrode
7
7
7
6
6
6
6
6
3-4
electrode
7
7
5
5
5
5
5
5

Table 7 and Fig. 6 show that the same experiment as in Experimental Example 1 was performed using a non-conductive slide glass instead of an ITO substrate. As a result of measuring the electrical resistance, no resistance was measured between electrodes 1 and 2, 3 and 4. It was confirmed that there was no electrical short between electrodes 1 and 2 and 3 and 4.

Time
(s)
measurement
location
1
2
3
4
5
6
7
8
30
1-2
electrode
X
X
X
X
X
X
X
X
3-4
electrode
X
X
X
X
X
X
X
X
60
1-2
electrode
X
X
X
X
X
X
X
X
3-4
electrode
X
X
X
X
X
X
X
X
90
1-2
electrode
X
X
X
X
X
X
X
X
3-4
electrode
X
X
X
X
X
X
X
X
120
1-2
electrode
X
X
X
X
X
X
X
X
3-4
electrode
X
X
X
X
X
X
X
X
150
1-2
electrode
X
X
X
X
X
X
X
X
3-4
electrode
X
X
X
X
X
X
X
X

<Experimental Example 2> Thermal curing of anisotropic conductive film

After the anisotropic conductive film manufactured with the composition of Example 2 was adhered to a Ti/Al/Ti substrate having a size of 1.5 mm*12 mm, a PI film (COF film) having copper electrodes formed with an electrode size of 8 μm and a space between the electrodes of 13 μm was attached on the anisotropic conductive film using an ACF Bonder (BD-02 Tabletop Heat Bonder (Pulse heater), electrodes of size 8 μm, and a space between the electrodes of 13 μm. Next, bonding was performed over time under conditions of 230°C and a bonding pressure of 130 MPa using OHASHI ENGINEERING Co., Ltd.) (Figs. 7(a) to 7(b)).

Table 8 summarizes the resistance measurement results of the conductive substrate sample. According to this, it can be confirmed that the resistance is stably measured below 10Ω and that the COF electrodes are electrically connected to the ITO.

Line
1
2
3
4
5
6
7
8
2-Point
Probe
1-2
electrode
5.8
4.4
3.8
4.2
6.1
8.0
6.7
6.7
3-4
electrode
6.3
4.6
3.7
3.3
3.9
5.7
5.5
7.2

In addition, the resistance was measured using a non-conductive slide glass instead of a Ti/Al/Ti substrate, and the results were summarized in Table 9.

Line
1
2
3
4
5
6
7
8
2-Point
probe
1-2
electrode
X
X
X
X
X
X
X
X
3-4
electrode
X
X
X
X
X
X
X
X

According to this, the electrical resistance measurement results showed that no resistance was measured between electrodes 1 and 2, 3 and 4. It was confirmed that there was no electrical short between electrodes 1 and 2 and 3 and 4.

<Experimental Example 3> Laser curing of anisotropic conductive film

The anisotropic conductive film (size: 1.5 mm * 12 mm) manufactured in Example 1 was attached on a Ti/Al/Ti substrate, and a PI film (COF film) formed with an electrode size of 8 μm and a gap (space) between the electrodes of 13 μm was placed on top of the anisotropic conductive film. Using laser sintering & curing equipment (FineTek Co., Ltd.), a laser power of 300 W was applied for 10 seconds. At this time, the temperature measured by the IR camera was 250°C. Using the substrate manufactured in this way, the resistance was measured in the same manner as in each Example 1. The measured resistance values are shown in the table. It was stably measured below 10Ω, and it could be confirmed that the electrodes of the COF and the Ti/Al/Ti substrate were electrically connected, which is summarized in Table 10.

Line
1
2
3
4
5
6
7
8
2-Point
probe
1-2
electrode
3.8
3.3
4.5
4.2
5.1
7.1
8.7
6.4
3-4
electrode
5.4
4.1
4.6
4.3
5.9
7.7
7.5
5.9

In addition, the same results were obtained using a nonconductive slide glass instead of the Ti/Al/Ti substrate, and the results are summarized in Table 11. According to the results of the electrical resistance measurement, no resistance was measured between electrodes 1 and 2, 3 and 4. It was confirmed that there was no electrical short between electrodes 1 and 2 and 3 and 4.

Line
1
2
3
4
5
6
7
8
2-Point
probe
1-2
electrode
X
X
X
X
X
X
X
X
3-4
electrode
X
X
X
X
X
X
X
X

At this time, the laser equipment used a surface laser method with a wavelength of 980 nm as shown in Fig. 9. The laser oscillated from the laser source is uniformly output to the area to be irradiated through the optical system. When pressure is required during bonding, transparent quartz with almost no laser absorption is placed between the laser and the sample, and the laser is irradiated while applying pressure to the sample using the quartz.

The laser passing through the quartz reaches the surface of the PI layer and the metal electrode layer of the COF film, and the temperature of the surface increases according to the laser absorption rate of the PI layer and the metal electrode layer. The heat heated by the laser for several seconds is instantaneously transferred to the anisotropic conductive film and/or the ITO or Ti/Al/Ti layer located under the metal electrode layer in a thermally conductive manner, so that sintering and curing occur, and the bonding process is performed.

At this time, the temperature of the metal electrode layer and the anisotropic conductive film was monitored through an IR camera image, and the real-time temperature during the laser process was 250°C.

<Experimental Example 4> Electron Microscope Photograph

In Experimental Example 3, after bonding the electrodes, the bonding material (anisotropic conductive film) portion was photographed with an electron microscope, and is shown in Fig. 10. According to this, it was confirmed that Ag was precipitated as a sintered body on the surface of the Cu electrode, and this was because the Ag component of the metal precursor was reduced to form a sintered body, forming a metal region, which is a conductive path that can electrically connect the upper and lower electrode directions. Meanwhile, the sintered body was subjected to elemental analysis via EDS, and is shown in Fig. 11. As a result, it was confirmed that the main component of the sintered body was Ag.

<Experimental Example 5> Micro LED Lighting

The lighting rate of the micro LED was evaluated by sintering and curing the metal precursor and the polymer, respectively, using an IR laser (Infrared (IR) Lasers, 1064 nm) on the anisotropic conductive film manufactured with the composition of Example 2 (Fig. 11). As a result, it was confirmed that 100% lighting occurred, and the cross-sectional analysis results confirmed that a metal layer was formed under the chip. The photographs of the experiment are shown in Figs. 12 to 14.

The above description is merely an example of the present invention, and those skilled in the art will appreciate that various modifications may be made without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed in this specification are not intended to limit the present invention but to explain it, and the spirit and scope of the present invention are not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all techniques within a scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

Claims (15)

A metal precursor comprising a metal ion providing electrical conductivity;
A curable resin comprising a curable polymer;
A phase separation inducing agent that induces phase separation of the metal reduced from the metal ion and the curable resin during curing of the curable resin; and
An anisotropic conductive film comprising a flow control agent that shortens curing time and controls flowability. In the first paragraph,
The above anisotropic conductive film is a free-standing anisotropic conductive film that is partially cured by first heating during manufacturing. In the second paragraph,
The above anisotropic conductive film is an anisotropic conductive film in which, when a second heating temperature higher than the first heating temperature is performed after the above anisotropic conductive film is manufactured, the metal particles in which the metal ions are reduced are sintered to form a sintered body. In the first paragraph,
The above anisotropic challenge film,
An anisotropic conductive film in which, when a cured product is formed between a first electrode and a second electrode, a conductive path is formed in the Z-axis direction in which the first electrode and the second electrode face each other, but no conductive path is formed in the X and Y-axis directions which are each perpendicular to the Z-axis direction. In paragraph 4,
The above anisotropic conductive film is an anisotropic conductive film in which a plurality of sintered bodies formed by reduction of the metal ions grow in the Z-axis direction to electrically connect the first electrode and the second electrode. In the first paragraph,
The above flow control agent is an anisotropic conductive film which is an acrylic polymer resin having a molecular weight of 10,000 to 1,100,000. delete In the first paragraph,
The above-mentioned conductive film is an anisotropic conductive film further comprising nanoparticles in an amount of 5 to 15 parts by weight relative to 60 parts by weight of a metal conductive precursor. In Article 8,
The above nanoparticle is an anisotropic conductive film including one selected from the group consisting of silver (Ag), gold (Au), indium (In), copper (Cu), indium tin oxide (ITO), palladium, platinum, nickel, and iridium. In Article 8,
The above nanoparticles are anisotropic conductive films having a size of 0.01 to 5.0 μm. A release film providing step for providing a release film that can easily peel off the applied composition and form a film;
A composition application step of applying a composition for producing an anisotropic conductive material, which comprises a metal precursor including a metal ion providing electrical conductivity on the release film, a curable resin including a curable polymer, a phase separation inducing agent inducing phase separation of the metal reduced from the metal ion and the curable resin during curing of the curable resin, and a flow control agent for shortening the curing time and controlling flowability, in a desired size; and
A method for manufacturing an anisotropic conductive film, comprising: a heating step of applying heat to a coated film to enable free-standing; In Article 11,
A method for manufacturing an anisotropic conductive film, further comprising a peeling step of peeling a coating film from the release film after the heating step to form an anisotropic conductive film. In Article 11,
A method for manufacturing an anisotropic conductive film, wherein the thickness of the coating film in the above composition application step is 30 to 200 μm. In Article 11,
A method for producing an anisotropic conductive film, wherein the composition for producing the above anisotropic conductive material further includes a flow control agent that shortens the curing time and controls flowability. In Article 14,
A method for producing an anisotropic conductive film, wherein the composition for producing the above anisotropic conductive material further contains a solvent and has a viscosity of 5 to 10,000 cP at 25°C.

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