WO2022075663A1 - Conductive particle, conductive material, and connection structure - Google Patents

Abstract

The present invention relates to a conductive particle comprising: a core; and a conductive layer provided on a surface of the core and having protrusions, wherein the conductive particle is characterized by containing palladium distributed in a first palladium zone formed in the interface between the conductive layer and the core and in a third palladium zone formed in the inner region of the protrusions.

Description

Conductive particles, conductive materials and connection structures

The present invention relates to conductive particles having a conductive layer on the surface of a core, and more particularly, to conductive particles used as a core conductive material of an anisotropic conductive adhesive material that connects fine-pitch circuits. It also relates to a conductive material and a bonded structure using the conductive particles.

Conductive particles are anisotropic conductive materials used in a dispersed form by mixing with a curing agent, adhesive, resin binder, for example, anisotropic conductive film, anisotropic conductive adhesive, anisotropic conductive paste, It is used for anisotropic conductive ink and anisotropic conductive sheet.

The anisotropic conductive material is FOG (Film on Glass; flexible substrate - glass substrate), COF (Chip on Film; semiconductor chip - flexible substrate), COG (Chip on Glass; semiconductor chip - glass substrate), FOB (Film on Board); Flexible substrate - glass epoxy substrate), etc.

Assuming that the anisotropic conductive material is, for example, bonding a semiconductor chip and a flexible substrate, the anisotropic conductive material is disposed on the flexible substrate and the semiconductor chip is laminated to harden the anisotropic conductive material under pressure/heating, so that the conductive particles are the electrode of the substrate It is possible to implement a connection structure for electrically connecting the electrode and the semiconductor chip.

When the conductive particles are used in the anisotropic conductive material, they are mixed with a curing agent, an adhesive, a resin binder, etc., and when it becomes a bonded structure after pressing/heating, it maintains the electrical connection between the upper and lower electrodes by curing/adhesiveness of the anisotropic conductive material. do.

The present invention has been devised to solve the above problems, and the technical object of the present invention is to provide conductive particles in which the conductive layer is formed with a stable and uniform thickness, and the size of the projections formed on the conductive layer can be adjusted aim to do

Conductive particles according to one aspect of the present invention,

A conductive particle comprising a core and a conductive layer provided on the surface of the core and having projections,

and palladium distributed in a first palladium region formed at an interface between the conductive layer and the core, and a third palladium region formed in an inner region of the protrusion.

In this case, it is preferable to include a second palladium region formed in the middle of the conductive layer.

In addition, the third palladium region preferably includes palladium nanoclusters having an average particle diameter of 30 nm to 130 nm.

In addition, in the first palladium region, more palladium nanoparticles are distributed than the surrounding area, and it is preferable that the palladium nanoparticles are attached to 95% or more of the core surface area.

In addition, the second palladium region is a region in which palladium nanoparticles are distributed more than the surrounding area.

In addition, it is preferable that the palladium concentration in the third palladium region is higher than the palladium concentration in the first palladium region or the second palladium region.

In addition, the conductive layer is preferably made of one or more alloys selected from the group consisting of Ni, Sn, Ag, Cu, Pd, Zn, W, P, B, and Au.

In addition, it is preferable to further include an insulating layer or insulating particles on the surface of the conductive layer.

In addition, it is preferable to use a hydrophobic rust preventive agent on the outermost layer of the conductive layer to be rust-preventive.

Another aspect of the present invention is an anisotropic conductive material comprising the aforementioned conductive particles.

Another aspect of the present invention is a connection structure including the conductive particles described above.

Another aspect of the present invention comprises the steps of manufacturing a core;

forming a first palladium region by attaching palladium particles to the surface of the core;

dispersing the core after step B) in a nickel plating solution to form a first nickel region;

forming a second palladium region by injecting a reducing agent into the core after step C) and then injecting a palladium precursor solution;

forming a second nickel region by injecting a nickel precursor onto the second palladium region after step D);

forming a third palladium region including palladium nanoclusters in one region of the surface of the second nickel region by adding a palladium precursor solution and a stabilizer to the core; and

It provides a method of manufacturing conductive particles comprising the step of forming a third nickel region on the second nickel region and the third palladium region.

In the conductive particles according to the present invention, palladium is provided at the interface of the conductive layer with the core so that elements constituting the conductive layer can grow.

In addition, palladium is included in the conductive layer to have an effect of stably and uniformly forming the conductive layer.

In addition, palladium is included in the form of nano-clusters inside the protrusions protruding from the conductive layer to perform the protrusion-forming function, and has the effect of controlling the size and height of the protrusions according to the size of the palladium nano-clusters.

As a result, the conductive layer has a uniform thickness on the core, and the size and height of the protrusions can be adjusted according to the conditions in which they are used. can be manufactured.

1 is a TEM photograph of conductive particles according to an embodiment of the present invention.

2 is a TEM photograph of a conductive layer region without projections of conductive particles according to an embodiment of the present invention.

3 is a graph showing the results of EDAX analysis in the middle region where there is no projection of the conductive layer.

4 is a TEM photograph of a projection region of a conductive layer of conductive particles according to an embodiment of the present invention.

5 is a graph showing the results of EDAX analysis in the middle region of the protrusion.

Prior to describing the present invention in detail below, it is to be understood that the terminology used herein is for the purpose of describing specific embodiments and is not intended to limit the scope of the present invention, which is limited only by the appended claims. shall. All technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art, unless otherwise stated.

Throughout this specification and claims, unless stated otherwise, the term comprise, comprises, comprising is meant to include the stated object, step or group of objects, and steps, and any other object. It is not used in the sense of excluding a step or a group of objects or groups of steps.

On the other hand, various embodiments of the present invention may be combined with any other embodiments unless clearly indicated to the contrary. Any feature indicated as particularly preferred or advantageous may be combined with any other feature and features indicated as preferred or advantageous. Hereinafter, embodiments of the present invention and effects thereof will be described with reference to the accompanying drawings.

<Challenger>

The conductive particles according to an embodiment of the present invention are conductive particles included between electrodes to electrically connect the electrodes, and at least one of the electrodes has an oxide film on its surface.

In general, conductive particles are contained in an anisotropic conductive material and are heat-compressed, and the conductive particles are electrically connected between the electrodes in such a way that the size of the conductive particles is deformed during compression and protrusions penetrate the electrodes. At this time, the inter-electrode spacing varies depending on the size of the particles used, but is usually about 3 µm to 20 µm.

The conductive particles include a core and a conductive layer having projections provided on the surface of the core.

The core according to the present embodiment is not particularly limited. For example, a resin particle or organic-inorganic hybrid particle|grains may be used for a core.

The resin particles are prepared by seed polymerization, dispersion polymerization, It is a copolymer obtained by polymerization by methods such as suspension polymerization and emulsion polymerization.

The organic-inorganic hybrid particles are particles including all organic inorganic particles, and may have a core-shell structure, a compound structure, and a composite structure. At this time, in the case of having a core-shell structure, when the core is an organic material, the shell is an inorganic material, and when the core is an inorganic material, the shell is an organic material. The organic used herein uses the above monomers or modified monomers or mixed monomers, and the inorganic used is oxides including SiO ₂ , TiO ₂ , Al ₂ O ₃ , ZrO ₂ , AlN, Si ₃ N ₄ , TiN, BaN Nitride, including WC, TiC, carbide including SiC, etc. can be used.

A method of forming the shell may be a chemical coating method, a sol-gel method, a spray coating method, a CVD (chemical vapor deposition method), a PVD (physical vapor deposition method), a plating method, or the like.

In addition, a form in which inorganic particles are dispersed in an organic matrix having a compound structure is possible, a form in which organic particles are dispersed in an inorganic matrix, and a form in which organic/inorganic are dispersed 50:50 to each other is also possible.

In addition, in the case of a compound structure, a material including polysiloxane or metaloxane may be used.

The size of the core is not particularly limited, but in consideration of the general electrode shape and surface roughness, it is preferably 6 μm or less, more preferably 1.5 μm to 5 μm, and still more preferably 1.5 μm to 4.5 μm.

The conductive layer may be composed of one or more elements such as P, B, Cu, Au, Ag, W, Mo, Pd, Co, and Pt on a Ni base. At this time, the conductive layer forms a single layer, but inside it consists of a single layer in which the concentration of each element except Ni is changed.

According to embodiments of the present invention, among the elements constituting the conductive layer, Pd is formed in the first palladium region where the conductive layer is formed at the interface with the core, the second palladium region is formed in the middle of the conductive layer, and the protrusion distributed in the third palladium region. At this time, it does not mean that palladium is not distributed at all except for the first palladium region, the second palladium region, and the third palladium region, but it means that the defined palladium region is present in a relatively high concentration compared to other peripheral regions. .

1 is a TEM photograph of conductive particles according to an embodiment of the present invention. According to this, the conductive particles show a first palladium region 10 , a second palladium region 20 , and a third palladium region 30 according to regions in which palladium is distributed.

The first palladium region 10 is formed by including palladium nanoparticles at the interface with the core in the conductive layer, which allows the remaining particles to form the conductive layer to grow well on the palladium nanoparticles. At this time, the palladium nanoparticles are attached to 95% or more of the surface of the core, preferably 99% or more, and more preferably over the entire surface.

The second palladium region 20 is formed by including palladium nanoparticles in the middle region of the conductive layer, and the particles to form the conductive layer, mainly Ni particles, are distributed once more in the middle region of the conductive layer. By doing so, the remaining particles constituting the conductive layer are thickly stacked so that the overall conductive layer can be thickened.

The third palladium region 30 is a region in which palladium is distributed inside the protrusion region, and palladium is distributed in the widest region. The third palladium region contains palladium nanoclusters, and the palladium clusters are distributed inside the conductive layer and perform the function of forming the core of the projections. to form At this time, it is preferable that the palladium nanoclusters have a particle diameter of 30 nm to 130 nm. If it is less than the above range, it is too small to perform the protrusion forming function, and if it exceeds the above range, there is a problem in that the protrusion becomes excessively large or it is not possible to form the protrusion uniformly.

As a result, the conductive layer is formed by growing Ni, Pd, P, B, Cu, Au, Ag, W, Mo, Co, and Pt particles to form polycrystals.

The thickness of the conductive layer of the conductive particles is suitable about 30 ~ 300nm. If the thickness of the conductive layer is thin, the resistance value increases, and if it is too thick, even if the conductive particles are slightly deformed under the heating/pressurization bonding condition of the anisotropic conductive material, the conductive layer and the core are peeled off, resulting in poor product reliability. A preferred thickness is 80-200 nm.

In some cases, noble metals such as gold, silver, platinum, and palladium are included in the surface layer of the conductive layer of the conductive particles. This is because the conductivity of the conductive particles can be increased and an anti-oxidation effect can be obtained. The method of forming the surface layer is not particularly limited, and conventionally known techniques such as general sputtering, plating, and vapor deposition may be used.

The shape of the projection of the conductive particles is not particularly limited, and may be a spherical shape, an elliptical shape, or a shape in which several particles gather to form a cluster. The most preferred protrusion shape is a mountain shape.

The size of the protrusion is not particularly limited, and it is preferably in a convex shape of 50 to 500 nm. If the size of the projections is too small or large, the effect of breaking the metal oxide layer and the binder resin is weakened, so the more preferable size of the projections is 100 to 300 nm.

The method for manufacturing conductive particles according to an embodiment of the present invention is not particularly limited. For example, a catalytic material may be applied to the surface of the core resin fine particles, and a conductive layer and protrusions may be formed through electroless plating. However, in order to create a necessary concentration gradient when forming the conductive layer, it is preferable to input the elements in multiple steps while changing the concentration of the elements.

It is preferable that the outermost conductive particle according to the embodiment of the present invention has an insulating layer. As electronic products are miniaturized and integrated, the pitch of the electrodes becomes smaller.

Methods for forming the insulating layer include a method of chemically attaching insulating particles to the outermost layer of conductive particles using a functional group, and a method of dissolving an insulating solution in a solvent and then coating it by spraying or immersion.

The conductive layer of the conductive particles of the present invention is preferably subjected to a rust prevention treatment. This is because the anti-rust treatment increases the contact angle with water to increase the reliability in a high-humidity environment, and has the effect of reducing the deterioration of the performance of the connection member by dissolving impurities in the water. Therefore, it is preferable to use a hydrophobic rust inhibitor including a phosphate ester or salt containing phosphoric acid, an alkoxysilane containing silane, an alkylthiol containing thiol, and a dialkyl disulfide containing sulfide. After dissolving the rust inhibitor in a solvent, methods such as immersion and spraying can be used.

The size of the conductive particles is not particularly limited, but is preferably 6 μm or less. More preferably, 5 µm or less is appropriate. This is because, in the place where the anisotropic conductive material manufactured by using the conductive particles of the present invention is used, the electrode gap is very small, so 6㎛ or more is rarely used.

<Method for producing conductive particles>

The method for manufacturing conductive particles according to an embodiment of the present invention may include a core dispersing step (S1), a protruding conductive layer forming step (S2), and a rust prevention step (S3), wherein the rust prevention step (S3) is optionally may be included.

At this time, the core dispersion step (S1) includes a core particle synthesis step (S1a) and a plating catalyst activation step (S1b).

First, in the core particle synthesis step (S1a), urethane-based, styrene-based, acrylate-based, benzene-based, epoxy-based, amine-based, imide-based monomers or modified monomers thereof or mixed monomers of the above monomers are used to seed, The copolymer is prepared by polymerization by methods such as polymerization, dispersion polymerization, suspension polymerization, and emulsion polymerization.

When the organic-inorganic hybrid particle has a core-shell structure, when the core is organic, the shell is inorganic, and when the core is inorganic, the shell is organic. The organic used herein uses the above monomers or modified monomers or mixed monomers, and the inorganic materials used include oxides including SiO2, TiO2, Al2O3, ZrO2, nitrides including AlN, Si3N4, TiN, and BaN, WC, TiC, and SiC. carbides and the like can be used.

As a method of forming the shell, a chemical coating method, a sol-gel method, a spray coating method, a CVD (chemical vapor deposition method), a PVD (physical vapor deposition method), a plating method, or the like may be used.

In addition, a form in which inorganic particles are dispersed in an organic matrix is also possible, a form in which organic particles are dispersed in an inorganic matrix, and a form in which organic/inorganic are dispersed 50:50 to each other is also possible.

For example, as the organic material, an ethoxylate triacrylate monomer and an ethoxylate diacrylate monomer are used to disperse a solution in which a solvent and a polymerization initiator are mixed. In this case, the dispersion treatment may include a homogenizer treatment using ultrasonic waves.

In addition, a solution containing a dispersion stabilizer and a surfactant is added to the dispersion treatment solution, and a polymerization process is performed under elevated temperature conditions to form core resin particles.

Subsequently, in the plating catalyst activation step (S1b), the core particles prepared in the previous step S1a are activated with the electroless plating catalyst.

Specifically, in the plating catalyst activation step (S1b), the core particles are treated with a surfactant and then pretreated using various methods known to sensitize the electroless plating catalyst, and then the sensitized core particles are treated with a precursor of the electroless metal plating catalyst. It is put into the containing solution and the activation treatment is performed.

The activated core particles are put into a solution containing a strong acid and stirred at room temperature to perform accelerated treatment, thereby obtaining catalytically treated core particles for electroless plating. In this case, it is preferable to use palladium as a catalyst for electroless plating, and the catalytically treated palladium forms a first palladium region.

Next, the protruding conductive layer forming step (S2) includes a core dispersing step (S2a) and a protruding conductive layer forming step (S2b).

In the core dispersing step (S2a), the core is dispersed by putting the core in a nickel base alloy plating solution, and nickel particles are plated on the surface of the core with the nickel base plating solution to form a first nickel region.

At this time, the nickel base alloy plating solution is prepared by sequentially dissolving the precursor of the nickel alloy element, the complexing agent, lactic acid, the stabilizer, and the surfactant, and the catalyst-treated core particles obtained in the step (S1b) are added to the prepared plating solution and dispersion treatment using an ultrasonic homogenizer.

It is preferable to adjust the pH of the dispersion treatment solution to pH 5.5 to 6.5 using ammonia water, etc., as it is possible to improve the adhesion and dispersibility between the insulating particles and the conductive layer in the initial Ni reduction reaction in the conductive layer forming step (S2b), which will be described later. Do. If the pH is less than 5.5, for example, pH 4 or less, the adhesion and dispersibility are good, but the reactivity is too low, so some particles may not be plated. This can lead to poor adhesion and dispersibility.

The step of forming the projection conductive layer (S2b) is a step of forming the conductive layer having projections while injecting the nickel precursor solution and the palladium precursor solution.

After the core dispersion step (S2a), a reducing agent is added to the core having the first nickel region formed on the surface, and then the palladium precursor solution is injected to form the second palladium region. A nickel precursor is added to the second palladium region to further form a second nickel region to increase the thickness of the conductive layer.

Next, a palladium precursor solution and a stabilizer are again introduced on the surface of the second nickel region to form a third palladium region in one region of the surface. At this time, in the third palladium region, the palladium nanoparticles form a cluster to form particles larger than the individual nanoparticles, and are formed in one section on the second nickel region.

As a result, the surface is divided into a second nickel region and a third palladium region, and when the nickel precursor solution is added to the upper portions again, nickel is formed on the second nickel region upper portion and the third palladium region upper portion to form a projection while forming a conductive layer A third nickel region to be thickened is formed.

That is, it is estimated that the mechanism by which the protrusion is formed in the above-described manufacturing method is as follows. When a reducing agent and an aqueous Ni solution are added in the plating solution, nickel particles are simultaneously generated by the reducing agent, and the nickel particles are attached to the surface of the microparticles to form a first nickel region. To form a thicker plating layer, a low concentration Pd precursor solution is added to adsorb Pd particles on the first nickel region, and at the same time, the reduced nickel nanoparticles form a second nickel region. Thereafter, a high concentration of a Pd precursor solution and a stabilizer are added to form large Pd clusters for protrusion formation, and palladium nanoclusters play a role as nuclei in protrusion formation. After that, the Ni precursor solution and the reducing agent are added to form a conductive layer having protrusions in which the palladium nanocluster part protrudes while nickel covers the surface.

Meanwhile, when the conductive layer is formed, a solution containing a precursor of at least one element selected from the group consisting of P, B, Cu, Au, Ag, W, Mo, Pd, Co and Pt is dividedly injected to obtain a concentration gradient of each element. It is possible to form a protruding conductive layer with

For example, in the core dispersion step (S2a), one or more precursors selected from P and B are input, and in the conductive layer forming step (S2b), one type of Cu, Au, Ag, W, Mo, Pd, Co, Pt An alloying element including a precursor of the above-selected element may be dividedly added to form a conductive layer having a concentration gradient and protruding.

At this time, the divided alloying element may be divided and added 2 to 5 times at intervals of 10 to 30 minutes, and may be divided and added 2 to 4 times at intervals of 15 to 25 minutes. At this time, the input amount may be divided into an increased content or input continuously as necessary, but it is preferable to increase the input amount according to the input speed for a certain time period as the concentration increases in the direction of the protrusion.

The optionally performed rust prevention step (S3) may be performed by introducing conductive particles into the rust preventive solution, but is not limited thereto.

As the rust preventive solution, a hydrophobic rust inhibitor including a phosphate ester or salt containing phosphoric acid, an alkoxysilane containing silane, an alkylthiol containing thiol, and a dialkyl disulfide containing sulfide may be used. As the hydrophobic rust preventive agent, an electroless nickel rust preventive agent including product name SG-1 sold by MSC may be used.

After the conductive particles are added, ultrasonic treatment or the like may be performed.

<Anisotropic conductive material>

An anisotropic conductive material can be prepared by dispersing the conductive particles of the present invention in a binder resin. Examples of the anisotropic conductive material include an anisotropic conductive paste, an anisotropic conductive film, and an anisotropic conductive sheet.

The resin binder is not particularly limited. For example, vinyl resins, such as a styrene type, acryl type, vinyl acetate type, thermoplastic resins, such as a polyolefin type, and a polyamide type, curable resin, such as a urethane type, an epoxy type, etc. are mentioned. The above resins may be used alone or in combination of two or more.

A radical initiator such as BPO (Benzoyl peroxide) or a photoinitiator such as TPO (Timethylbenzoyl phenylphosphinate) for the purpose of polymerization or curing to the resin, an epoxy latent curing agent such as HX3941HP, etc. can be used alone or in combination.

In addition, other substances may be added to the anisotropic conductive material binder resin within a range that does not impede the achievement of the object of the present invention. For example, colorants, softeners, heat stabilizers, light stabilizers, antioxidants, inorganic particles, and the like.

The manufacturing method of the said anisotropic conductive material is not specifically limited. For example, it can be used as an anisotropic conductive paste by uniformly dispersing conductive particles in a resin binder, or it can be used as an anisotropic film by spreading it thinly on a release paper.

<connection structure>

The connection structure according to an embodiment of the present invention connects circuit boards between circuit boards using the conductive particles according to the embodiment of the present invention or the anisotropic conductive material according to the embodiment of the present invention. For example, it can be used as a method of connecting a display semiconductor chip of a smartphone and a glass substrate constituting a circuit or a flexible substrate constituting a circuit, and connecting μ -LED, mini-LED and a circuit board.

The connection structure of the present invention does not cause malfunction of the circuit due to poor connection of the circuit or a sudden increase in resistance.

Hereinafter, the present invention will be described in more detail through specific and various examples, which are intended to help the understanding of the present invention, and the technical spirit of the present invention is not limited thereto.

[Example]

Example 1

1) Manufacture of core resin fine particles (S1a)

In a 3L glass beaker, 800 g of monomer TMPETA (Trimethylolpropane ethoxylate triacrylate), 50 g of HDEDA (1,6-Hexanediol ethoxylate diacrylate), and 800 g of DVB (Divinylbenzrne) were put, 5 g of initiator BPO was added, and treated in a 40 kHz ultrasonic bath for 10 minutes to prepare the first solution. .

Dissolve the dispersion stabilizer PVP (Polyvinylpyrrolidone)-30K 500g and the surfactant Solusol (Dioctyl sulfosuccinate sodium salt) in 4,000 g of deionized water in a 5L PP beaker to prepare a second solution.

The first solution and the second solution were put in a 50L reactor, 41,000 g of deionized water was added, treated with an ultrasonic homogenizer (20 kHz, 600 W) for 90 minutes, and the temperature was raised to 85° C. while rotating the solution at 120 rpm. After the solution reached 85°C, it was maintained for 16 hours to carry out polymerization process.

The polymerized fine particles were filtered, washed, classified and dried to obtain core resin fine particles. For the average diameter of the prepared core resin fine particles, the mode value measured using a Particle Size Analyzer (BECKMAN MULTISIZER TM3) was used. At this time, the number of measured core particles is 75,000. The average diameter was 3.02 mu m.

2) Catalyst treatment process (S1b)

30 g of the prepared core resin fine particles were placed in 800 g of deionized water and 1 g of the surfactant Triton X100 and treated in an ultrasonic bath for 1 hr to remove excess unreacted monomers and oil components present in the core resin fine particles. A cleaning and degreasing process was performed. . At the end of the washing and degreasing process, a water washing process was performed three times using deionized water at 40°C.

Then, Pd catalyst treatment was carried out. After dissolving 150 g of stannous chloride and 300 g of 35-37% hydrochloric acid in 600 g of deionized water, the washed and degreased fine core resin particles were added, sensitized by immersion and stirring at 30 ° C for 30 minutes, and then washed with water 3 times. .

1 g of palladium chloride and 200 g of 35-37% hydrochloric acid were added to the sensitized core resin fine particles in 600 g of deionized water, and activation treatment was performed at 40° C. for 1 hour. After the activation treatment, the water washing process was performed three times.

The activated core resin fine particles were put into a solution of 35-37% hydrochloric acid, 100 g of hydrochloric acid, and 600 g of deionized water, and stirred at room temperature for 10 minutes to accelerate treatment. After the accelerated treatment, water washing was performed three times to obtain catalyst-treated core resin fine particles for electroless plating.

3) Core dispersion (S2a)

In a 5L reactor, in 3,200 g of deionized water, 260 g of nickel sulfate as a Ni salt, 5 g of sodium acetate as a complexing agent, 2 g of lactic acid, 0.001 g of Pb-acetate as a stabilizer, 0.001 g of sodium thiosulfate, and 0.03 g of Triton 80 as an anti-agglomeration agent were dissolved in order. (a) was prepared. The catalyst-treated fine core resin particles were added to the prepared solution (a), and dispersion treatment was performed for 10 minutes using an ultrasonic homogenizer. After dispersion treatment, solution (b) was prepared by adjusting the solution pH to 5.5 using ammonia water.

4) Formation of a conductive layer with projections (S2b)

A solution (c) was prepared by dissolving 350 g of deionized water and 200 g of sodium hypophosphite as a reducing agent in a 1L beaker.

A solution (d) was prepared by dissolving 250 g of deionized water, 100 g of nickel sulfate, and 10 g of hydrochloric acid in a 1L beaker.

A solution (e) was prepared by dissolving 100 g of deionized water, 0.005 g of PdCl2, and 10 g of hydrochloric acid in a 1L beaker.

A solution (f) was prepared by dissolving 400 g of deionized water and 300 g of sodium hypophosphite as a reducing agent in a 1L beaker.

A solution (g) was prepared by dissolving 100 g of deionized water, 0.05 g of PdCl2, 30 g of hydrochloric acid, Triton X-100 as a stabilizer, and 10 g of sodium hypophosphite in a 1L beaker.

A solution (h) was prepared by dissolving 200 g of deionized water and 150 g of sodium hypophosphite as a reducing agent in a 1L beaker.

A solution (i) was prepared by dissolving 150 g of deionized water, 50 g of nickel sulfate, and 10 g of hydrochloric acid in a 1 L beaker.

In a state where the temperature of the 5L reactor (solution (b-1)) is maintained at 55°C, the solution (c) is introduced in an amount of 10 g per minute by a metering pump, and the reactor temperature is heated to reach 75°C in 35 minutes and maintained did

After the addition of the solution (c) is completed, it is maintained for 10 minutes, and after adding the solution (e), it is maintained for 5 minutes, and the solutions (d) and (f) are simultaneously added in an amount of 10 g per minute by a metering pump.

The solutions (d) and (f) are maintained for 10 minutes after the input is completed, and the cluster is maintained after adding the solution (g).

The solution (g) is added and maintained for 10 minutes, and the solution (h) and solution (i) are added in an amount of 10 g per minute with a metering pump.

After the solution (h) and solution (i) were added and maintained for 10 minutes, Ni-plated protrusion conductive particles were obtained.

Comparative Example 1

In Example 1, (c) solution was 200 g of deionized water and 150 g of sodium hypophosphite as a reducing agent, plating was performed, and disintegration fixing was performed to release aggregation of conductive particles, followed by deionized water 200 g and reducing agent hypophosphorous acid. (d) solution of 150 g of sodium, 10 g of Triton X-100, a protrusion forming agent, and 0.05 g of sodium citrate, a stabilizer, was prepared, and the same method as in Example 1 was performed using a metering pump.

[Experimental example]

Experimental Example 1

A TEM photograph of the conductive layer region without projections of the conductive particles according to Example 1 is shown in FIG. 2 . According to this, the second palladium region in which palladium is distributed in the middle region of the non-protrusion conductive layer is confirmed as the bright region.

In addition, FIG. 3 is an EDAX analysis result of the middle region of the non-protrusion region of the conductive layer, and it is confirmed that Ni is distributed throughout the conductive layer, but there is a second palladium region in the middle region.

Experimental Example 2

A TEM photograph of the projection region of the conductive layer of the conductive particles according to Example 1 is shown in FIG. 4 . According to this, the third palladium region in which palladium is distributed in the middle region of the conductive layer is confirmed as the bright region.

In addition, FIG. 5 is an EDAX analysis result in the middle region of the protrusion, and it is confirmed that there is a third palladium region in which palladium nanoclusters are distributed in the center of the protrusion.

A TEM-EDAX analysis photograph of the conductive particles according to Example 1 is shown in FIG. 2 , and according to this, it was confirmed that there is no Pd or a very small amount in the region where there is no projection of the conductive layer.

Features, structures, effects, etc. exemplified in each of the above-described embodiments may be combined or modified for other embodiments by those of ordinary skill in the art to which the embodiments belong. Accordingly, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention.

<Explanation of code>

10: first palladium region

20: second palladium region

30: 3rd Palauum area

Claims (12)

1. A conductive particle comprising a core and a conductive layer provided on the surface of the core and having projections,

   Conductive particles comprising palladium distributed in a first palladium region formed at an interface between the conductive layer and the core and a third palladium region formed in an inner region of the protrusion.
2. The method of claim 1,

   Conductive particles including a second palladium region formed in the middle of the conductive layer.
3. The method of claim 1,

   Conductive particles comprising palladium nanoclusters having an average particle diameter of 30 nm to 130 nm in the third palladium region.
4. The method of claim 1,

   In the first palladium region, more palladium nanoparticles are distributed than the surrounding conductive particles, and the palladium nanoparticles are attached to 95% or more of the core surface area.
5. The method of claim 1,

   In the second palladium region, the conductive particle is a region in which palladium nanoparticles are distributed more than the periphery.
6. The method of claim 1,

   The conductive particles having a palladium concentration in the third palladium region is higher than the palladium concentration in the first palladium region or the second palladium region.
7. 7. The method of claim 6,

   The conductive layer is conductive particles made of one or more alloys selected from the group consisting of Ni, Sn, Ag, Cu, Pd, Zn, W, P, B, and Au.
8. 8. The method of claim 7,

   Conductive particles further comprising an insulating layer or insulating particles on the surface of the conductive layer.
9. 9. The method of claim 8,

   Conductive particles that are rust-prevented by using a hydrophobic rust preventive agent on the outermost layer of the conductive layer.
10. An anisotropic conductive material comprising the conductive particles of any one of claims 1 to 9.
11. A connection structure comprising the conductive particles of any one of claims 1 to 9.
12. A) preparing the core;

    B) forming a first palladium region by attaching palladium particles to the surface of the core;

    C) dispersing the core after step B) in a nickel plating solution to form a first nickel region;

    D) forming a second palladium region by injecting a reducing agent into the core after step C) and then injecting a palladium precursor solution;

    E) forming a second nickel region by injecting a nickel precursor onto the second palladium region after step D);

    F) adding a palladium precursor solution and a stabilizer to the core to form a third palladium region including palladium nanoclusters in one region of the surface of the second nickel region; and

    G) forming a third nickel region on the second nickel region and the third palladium region.

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