TW201841169A - Conductive particle sorting method, circuit connection material, connection structure body and manufacturing method therefor, and conductive particle - Google Patents

Abstract

The present disclosure relates to a conductive particle sorting method. The sorting method comprises: a step for determining whether a metal that constitutes an outermost layer of a conductive particle satisfies the following first condition; and a step for determining whether the conductive particle satisfies the following second condition. A conductive particle that satisfies both the first condition and the second condition is determined to be good. First Condition: electrical conductivity at 20 DEG C is 40*106 S/m or less. Second Condition: volume specific resistance during application of a 2 kN load is 15 m[Omega]cm or less.

Description

Selection method of conductive particles, circuit connection material, connection structure and manufacturing method thereof, and conductive particles

The present disclosure relates to a method for selecting conductive particles, a circuit connection material, a connection structure and a manufacturing method thereof, and conductive particles.

A driving integrated circuit (IC) is mounted on a glass panel for a liquid crystal and an organic light-emitting diode (OLED) display. The method can be roughly divided into two types: Chip-on-Glass (COG) mounting and Chip-on-Flex (COF) mounting. In COG mounting, a driving IC is directly bonded to a glass panel using an anisotropic conductive adhesive containing conductive particles. On the other hand, in COF mounting, a driving IC is bonded to a flexible tape having metal wiring, and these are bonded to a glass panel using an anisotropic conductive adhesive containing conductive particles. Here, the anisotropy means that it is conductive in a pressure direction and maintains insulation in a non-pressure direction. The anisotropic conductive adhesive containing conductive particles may be formed in a film shape in advance, and the film is called an anisotropic conductive film.

Up to now, indium tin oxide (ITO) wiring has been the mainstream of wiring on glass panels, but it is being replaced with indium zinc oxide (IZO) for the purpose of improving productivity or smoothness. Furthermore, in recent years, an electrode formed by laminating a plurality of layers of Cu, Al, Ti, and the like on a glass panel, and a composite multilayer electrode having ITO or IZO formed on the outermost surface are being developed. For such an electrode having high flatness and using a high hardness material such as Ti, it is necessary to obtain stable connection resistance.

Patent Document 1 discloses a method for producing a conductive fine particle including a substrate fine particle and a conductive film formed on a surface thereof, and the conductive film having protrusions raised on the surface. According to this document, the conductive film has excellent conductive reliability of the conductive fine particles having protrusions.

Patent Document 2 discloses conductive particles including substrate particles and a nickel-boron conductive layer provided on a surface thereof. According to this document, the nickel-boron conductive layer has a moderate hardness. Therefore, when a member to be connected between electrodes is used, the oxide film on the surface of the electrode and the conductive particles can be sufficiently excluded, and the connection resistance can be reduced.

Patent Document 3 discloses a conductive particle including resin particles, an electroless metal plating layer covering the surface thereof, and a metal sputtered layer other than Au that forms an outermost layer. According to this document, since the surface of the resin particles is covered with electroless metal plating, the adhesion to the surface of the resin particles is improved, and the outermost layer is used as a metal sputtered layer, whereby good connection reliability can be obtained. [Prior Art Literature] [Patent Literature]

Patent Literature 1: Japanese Patent No. 4563110 Patent Literature 2: Japanese Patent Laid-Open No. 2011-243455 Patent Literature 3: Japanese Patent Laid-Open No. 2012-164454

[Problems to be Solved by the Invention] Furthermore, regarding the conductive particles used in the manufacturing process of the display or the anisotropic conductive film containing the same, panel manufacturers have selected from a variety of materials suitable for the electrode surface. To use. For example, circuits having titanium on the surface used in organic electroluminescence (EL) displays, etc., are formed with titanium oxide on the outermost surface and are non-conducting. Therefore, a conductive layer having a harder plating layer than the conventional one is used particle. Thereby, during the crimping, the conductive particles penetrate the outermost non-conductive film and come into contact with the conductive portion inside the electrode, thereby achieving low resistance. However, if, for example, the conductive particles modified by physical methods are applied to the electrode of the ITO film, there is a problem that the conductive particles before the improvement may have low generality such as low resistance.

Recently, with the rapid commercialization of display-related products, competition among panel manufacturers has intensified. Among panel makers, there are manufacturers who are committed to achieving uniformity in the types of anisotropic conductive films in order to improve cost competitiveness. However, in reality, it is difficult to unify the types of the anisotropic conductive film due to the following reasons.

First, the electrode circuits of liquid crystal displays and organic EL displays are different. For example, liquid crystal displays mainly use oxide-based transparent conductive films (ITO, IZO, Indium Gallium Zinc Oxide (IGZO), Indium Gallium Oxide (IGO), Zinc Oxide, ZnO), etc.). On the other hand, organic EL displays mainly use electrode materials mainly composed of metals such as titanium, chromium, aluminum, and tantalum. In addition, the surface of the electrode may be coated with an organic material such as an acrylic resin, or an inorganic material such as SiN _x or SiO _x for the purpose of protecting the electrode portion or high reliability. Furthermore, examples of the electrode circuits other than the display substrate include flexible printed circuits (FPCs) and integrated circuits (ICs). Various electrodes such as gold, copper, and nickel are used for these electrodes.

This disclosure has been made in view of the above-mentioned circumstances, and an object thereof is to provide a method for selecting conductive particles having sufficiently high versatility with respect to a circuit electrode included in a circuit member to be connected. In addition, an object of the present disclosure is to provide a conductive particle, a circuit connection material using the same, a connection structure, and a method of manufacturing the same. [Means for solving problems]

The present disclosure relates to a method for selecting conductive particles. The selection method includes a step of determining whether the metal constituting the outermost layer of the conductive particle satisfies the following first condition, and a step of determining whether the conductive particle satisfies the following second condition, and which will satisfy both the first condition and the second condition. The conductive particles were judged to be good. First condition: Electrical conductivity at 20 ° C is 40 × 10 ⁶ S / m or less Second condition: Volume specific resistance when load is 2 kN is 15 mΩcm or less

By using conductive particles that satisfy both the first and second conditions, it is possible to reduce conductive particles and electrodes relative to circuit electrodes of various surface compositions (transparent conductive films of oxide systems such as ITO and metal electrodes such as Ti). The resistance of the contact surface of the surface, so that a good connection resistance can be obtained. The present inventors have found that the second condition is particularly useful in that a good connection resistance can be achieved and that conductive particles having high versatility are selected. The load of 2 kN is presumed to be a state in which the conductive particles are hardly flat. Therefore, compared with the case where a load is large, it is thought that the resistance value of the surface of a conductive particle can be detected with high sensitivity. In addition, in the actual connection portion, conductive particles having different flattening ratios are mixed between a pair of opposing electrodes due to variations in the particle diameter of the conductive particles or fine unevenness on the electrode surface. That is, those conductive particles also include those which are hardly flat. As described above, even if the other conductive particles selected by the method of the present disclosure are slightly flat, the contribution to the reduction in resistance of the connection portion is large, and a good connection resistance can be obtained as a whole. In contrast, if the conductive particles that do not satisfy either of the first condition and the second condition are slightly flat, the contribution to the reduction in resistance of the connection portion is small. Furthermore, the term "opposing" in this specification means that a pair of members face each other. [Effect of the invention]

According to the present disclosure, it is possible to provide a method of selecting conductive particles having sufficiently high versatility with respect to a circuit electrode included in a circuit member to be connected. In addition, according to the present disclosure, it is possible to provide a conductive particle, a circuit connection material using the same, a connection structure, and a method of manufacturing the same.

Hereinafter, embodiments of the present disclosure will be described in detail. However, the present invention is not limited to the following embodiments.

<Selection method of conductive particles> The selection method of conductive particles in this embodiment includes a step of determining whether the metal constituting the outermost layer of the conductive particles satisfies the following first condition, and a step of determining whether the conductive particles meet the following second condition. The conductive particles satisfying both the first condition and the second condition were judged to be good. First condition: Electrical conductivity at 20 ° C is 40 × 10 ⁶ S / m or less Second condition: Volume specific resistance when load is 2 kN is 15 mΩcm or less

By using conductive particles that satisfy both the first and second conditions, it is possible to reduce conductive particles and electrodes relative to circuit electrodes of various surface compositions (transparent conductive films of oxide systems such as ITO and metal electrodes such as Ti). The resistance of the contact surface of the surface, so that a good connection resistance can be obtained.

FIG. 1 (a) is a schematic cross-sectional view showing an enlarged connection portion of a connection structure manufactured using conductive particles selected by the method of the present embodiment. The conductive particles 1 (the conductive particles 1 a and 1 b) shown in FIG. 1 (a) satisfy both the first condition and the second condition. FIG. 1 (b) is a schematic cross-sectional view showing an enlarged connection portion of a connection structure manufactured using conductive particles 2 (2a, 2b) that do not satisfy either of the first and second conditions. In these figures, the thickness of the arrows indicates the ease of current flow.

As shown in FIG. 1 (a), at the connection portion of the connection structure 10, the circuit electrodes 3 a of the pair of circuit members 3 and the circuit members 4 facing each other due to the variation in the particle size of the conductive particles 1 are opposite to each other. In the circuit electrodes 4a, conductive particles 1 having different flattening ratios are mixed. As shown schematically in FIG. 1 (a), among the three conductive particles 1 a, 1 b, and 1 a, two conductive particles 1 a and 1 a are almost not flat. Even when the conductive particles 1 (the conductive particles 1 a and 1 b) are slightly flat, they contribute to the reduction in resistance of the connection portion, and therefore, good connection resistance can be obtained as a whole. On the other hand, if the conductive particles 2 (2 a and 2 b) shown in FIG. 1 (b) are slightly flat, the contribution to the reduction in resistance of the connection portion will be small. Here, the case where conductive particles having different flattening ratios are mixed due to the variation in the particle size of the conductive particles is illustrated here. However, even if the particle diameters of the conductive particles are sufficiently uniform, the degree of flattening of the conductive particles may be caused by the circuit electrode 3a The unevenness of the surface of the circuit electrode 4a changes.

The electrical conductivity of the metal of the outermost layer in the first condition can be measured using, for example, a conductivity measuring device (device name: SIGMATEST, manufactured by Japan Foerster Co., Ltd.). However, the conductive particles are generally small and difficult to measure with the device. Therefore, instead of actually measuring the conductivity using such a device, the elements constituting the outermost layer can be analyzed, and the conductivity can be determined according to the type of the element. From the viewpoint of further reducing the connection resistance of the connection portion of the connection structure, the first condition (conductivity at 20 ° C. of the metal layer) may be 1 × 10 ⁶ S / m to 40 × 10 ⁶ S / m It can also be set to 5 × 10 ⁶ S / m to 40 × 10 ⁶ S / m.

The volume specific resistance under the second condition can be measured using, for example, a powder resistance measurement system (device name: PD51, manufactured by Mitsubishi Chemical Analytech Co., Ltd.). Specifically, 2.5 g of conductive particles were put into a dedicated unit of the device, and the device was used to measure the volume specific resistance of the conductive particles when a load of 2 kN was applied. In addition, the amount of the conductive particles to be charged is sufficient as long as the bottom surface of the dedicated unit can be filled, so it is only required to be 0.5 g or more. The measurement load can be arbitrarily changed.

FIG. 2 is a graph showing an example of a measurement result of a volume specific resistance. The results shown in FIG. 2 are measured in units of 2 kN from a load of 2 kN to a load of 20 kN. In this embodiment, a volume specific resistance of 2 kN is used as an index. From the viewpoint of further reducing the connection resistance of the connection portion of the connection structure and obtaining a more versatile circuit connection material, the second condition (the specific volume resistance when a load of 2 kN is applied) can be set to 10 mΩcm or less. It can be set to 7.5 mΩcm or less and 5 mΩcm or less.

<Conductive Particles> The conductive particles are not particularly limited as long as they have compressive properties. Examples of the conductive particles include core-shell particles having a core particle containing a resin material and a metal layer covering the core-shell particles. The metal layer does not need to cover the entire surface of the core particle, and may be a state where a part of the surface of the core particle is covered with the metal layer. In addition, the metal layer may have a single-layer structure or a multilayer structure.

The particle diameter of the conductive particles is generally smaller than the minimum value of the interval between the electrodes of the connected circuit members. When there is a deviation in the height of the connected electrodes, the average particle diameter of the conductive particles is preferably larger than the deviation in height. From this viewpoint, the average particle diameter of the conductive particles is preferably 1 μm to 50 μm, more preferably 1 μm to 20 μm, still more preferably 2 μm to 10 μm, and even more preferably 2 μm to 6 μm. In addition, the "average particle diameter" in this specification means the value calculated | required by observation by the differential scanning electron microscope. That is, one particle is arbitrarily selected, and it is observed with a differential scanning electron microscope, and its maximum diameter and minimum diameter are measured. The square root of the product of the maximum diameter and the minimum diameter is taken as the particle diameter of the particles. In this method, the particle diameter of 50 particles arbitrarily selected is measured and the average value is taken to obtain the average particle diameter of the particles.

As described above, the volume specific resistance of the other conductive particles to be selected at a load of 2 kN is 15 mΩcm or less. From the viewpoint of further reducing the connection resistance of the connection portion of the connection structure and obtaining a more versatile circuit connection material, the volume specific resistance is preferably 0.1 mΩcm to 10 mΩcm, more preferably 0.1 mΩcm to 7.5 mΩcm, It is more preferably 0.1 mΩcm to 5 mΩcm or less.

The compression elastic coefficient (20% K value) of the conductive particles at a compression displacement of 20% (at a compression of 20%) at 25 ° C is preferably 0.5 GPa to 15 GPa, and more preferably 1.0 GPa to 10 GPa. The compressive hardness K is an index of the softness of the conductive particles. With a K% value of 20%, when the opposing electrodes are connected to each other, the conductive particles are moderately flattened between the electrodes, thereby easily ensuring the contact between the electrodes and the particles. Area, it tends to further improve connection reliability.

The 20% K value of the conductive particles can be determined by the following method using a Fischerscope H100C (manufactured by Fischer Instruments). A conductive particle dispersed on a glass slide was compressed at a speed of 0.33 mN / s. With this, a stress-strain curve is obtained, and a 20% K value is obtained from the curve. Specifically, when the load F (N), displacement S (mm), particle radius R (mm), elastic coefficient E (Pa), and Poisson's ratio (σ) are used, a compression type of an elastic ball can be used. F = (2 ^1/2 / 3) × (S ^3/2 ) × (E × R ^1/2 ) / (1-σ ² ), and by the following formula K = E / (1-σ ² ) = (3/2 ^1/2 ) × F × (S ^-3/2 ) × (R ^-1/2 ). Furthermore, if the deformation rate is X (%) and the diameter of the ball is D (μm), the K value of the arbitrary deformation rate can be obtained by the following formula: K = 3000F / (D ² × X ^3/2 ) × 10 ⁶ . The deformation rate X can be calculated by the following formula X = (S / D) × 100. The maximum test load in a compression test is set to 50 mN, for example.

(Core Particles) As described above, the conductive particles in this embodiment are core-shell type particles and include core particles. With conductive particles having core particles, the range of physical property design of the conductive particles themselves is greatly expanded. In addition, compared with metal powder, the size uniformity of conductive particles is also improved. Therefore, it is easy to make conductive in the connection of various components. Particle optimization.

Specific examples of the core particles include various plastic particles. Examples of the plastic particles include those formed from at least one resin selected from the group consisting of acrylic resins such as polymethyl methacrylate and polymethyl acrylate; polyethylene, polypropylene, polyisobutylene, and poly Polyolefin resin such as butadiene; polystyrene resin, polyester resin, polyurethane resin, polyamide resin, epoxy resin, polyvinyl butyral resin, rosin Resin, terpene resin, phenol resin, guanamine resin, melamine resin, oxazoline resin, carbodiimide resin, silicone resin, etc. Furthermore, as the plastic particles, those resins may be composited with inorganic substances such as silicon dioxide.

As the plastic particles, from the viewpoint of ease of controlling the compression recovery rate and the compression hardness K value, plastic particles containing a resin obtained by polymerizing one type of polymerizable monomer having an ethylenically unsaturated group may be used, or plastic particles containing Plastic particles of a resin obtained by copolymerizing two or more kinds of polymerizable monomers having an ethylenically unsaturated group. When a resin is obtained by copolymerizing two or more polymerizable monomers having an ethylenically unsaturated group, a non-crosslinkable monomer and a crosslinkable monomer are used in combination, and the copolymerization ratio and type of these are appropriately adjusted. , Can easily control the compression recovery rate and compression hardness K value of plastic particles. As the non-crosslinkable monomer and the crosslinkable monomer, for example, a monomer described in Japanese Patent Laid-Open No. 2004-165019 can be used.

The average particle diameter of the plastic particles is preferably 1 μm to 50 μm. Furthermore, from the viewpoint of high-density mounting, the average particle diameter of the plastic particles is more preferably 1 μm to 20 μm. In addition, when the unevenness of the electrode surface is uneven, the average particle diameter of the plastic particles is more preferably from 2 μm to 10 μm from the viewpoint of maintaining the connected state more stably.

(Metal layer) In this embodiment, the outermost layer of the conductive particles is a metal layer containing a metal having a conductivity of 40 × 10 ⁶ S / m or less at 20 ° C. By adopting such a configuration, good connection reliability can be obtained. The outermost layer herein refers to a range within 50 nm from the surface of the metal layer. The conductivity of the metal constituting the outermost layer at 20 ° C is 40 × 10 ⁶ S / m or less, preferably 1 × 10 ⁶ S / m to 40 × 10 ⁶ S / m, and more preferably 5 × 10 ⁶ S / m m ～ 20 × 10 ⁶ S / m.

The metal layer may be a single metal or an alloy. Examples of the metal having a conductivity of 40 × 10 ⁶ S / m or less include Al, Ti, Cr, Fe, Co, Ni, Zn, Zr, Mo, Pd, In, Sn, W, and Pt. For example, the metal layer is preferably at least one selected from the group consisting of Ni, Ni / Au (a Au layer is provided on the Ni layer. The same applies hereinafter), Ni / Pd, Ni / W, Cu, and NiB. Formed from a metal. The metal layer may be formed by a general method such as plating, vapor deposition, or sputtering, or may be a thin film. When the metal layer is formed by plating with respect to the plastic particles, the metal layer preferably contains Ni, Pd, or W from the viewpoint of the plating property of the plastic. Furthermore, in order to effectively remove the resin between the electrode and the particles at the time of crimping and further obtain low resistance, the metal layer preferably contains Ni. Ni has the following advantages: not only is it excellent in resin removal properties during crimping, but it is also superior in plating properties and corrosion resistance compared to Au, Cu, and Ag with high electrical conductivity, and it is also excellent in supply stability and price. .

From the viewpoint of achieving a balance between continuity and price, the thickness of the metal layer is preferably 10 nm to 1000 nm, more preferably 20 nm to 500 nm, and even more preferably 50 nm to 250 nm.

From the viewpoint of improving the insulation between the adjacent electrodes, the conductive particles may have a layer of an insulating material (for example, an organic film) or an insulating fine particle (for example, an organic fine particle or an inorganic fine particle) attached to the outside of the metal layer. Formed adhesion layer. The thickness of the adhesion layer is preferably about 50 nm to 1000 nm. In addition, it is preferable that the adhesion layer is formed with respect to the conductive particles confirmed to satisfy the first condition and the second condition. The thicknesses of the metal layer and the adhesion layer can be measured by, for example, a scanning electron microscope (SEM), a transmission electron microscope (TEM), or an optical microscope. Furthermore, protrusions may be formed on the surface of the metal layer. With the metal layer having protrusions, the resin removal at the time of crimping becomes effective, the contact point with the electrode increases, and the inside of the electrode can be further contacted with the conductive particles, etc. By these effects, further low resistance can be achieved.

<Circuit connection material> The circuit connection material of this embodiment is a circuit member for connecting circuit members to each other and electrically connecting circuit electrodes (for example, connection terminals) included in the circuit members to each other. The circuit connection material includes an adhesive component that is hardened by light or heat, and conductive particles dispersed in the adhesive component, and the conductive particles satisfy both the first condition and the second condition.

The circuit connection material can be prepared by dispersing conductive particles in an adhesive component. As the circuit connection material, a paste-like adhesive composition may be used as it is, or an anisotropic conductive film obtained by forming it into a film may be used. Regarding the amount of the conductive particles to be blended, it is preferable to set the total volume of the circuit connection material to 100 parts by volume from the viewpoint that the conductivity between the counter electrodes and the insulation between adjacent electrodes are well balanced. 0.1 to 30 parts by volume, more preferably 0.5 to 15 parts by volume, even more preferably 1 to 7.5 parts by volume.

Regarding the compounding amount of the adhesive component, it is easy to maintain the gap between the electrodes during and after the connection of the circuit, and to ensure the strength and coefficient of elasticity required for excellent connection reliability. When the total mass is 100 parts by mass, it is preferably 10 parts by mass to 90 parts by mass, more preferably 20 parts by mass to 80 parts by mass, and even more preferably 30 parts by mass to 70 parts by mass.

Although it does not specifically limit as an adhesive component, For example, the composition containing the epoxy resin and the latent hardener of an epoxy resin (henceforth a "first composition"), the radical polymerizable substance, and A composition of a hardener that generates free radicals upon heating (hereinafter, referred to as a "second composition"), or a mixed composition of a first composition and a second composition.

Examples of the epoxy resin contained in the first composition include bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, phenol novolac epoxy resin, and cresol novolac. Varnish type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, alicyclic epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, B Internal urea type epoxy resin, isocyanurate type epoxy resin, aliphatic chain epoxy resin, etc. These epoxy resins can be halogenated or hydrogenated. These epoxy resins may be used in combination of two or more.

As the latent hardener contained in the first composition, it is sufficient to harden the epoxy resin. Examples of such a latent hardener include anionic polymerizable catalyst-type hardeners and cation polymerizable catalysts. Type hardener, addition polymerization type hardener, and the like. These may be used alone or as a mixture of two or more. Among these, an anionic polymerizable or a cationic polymerizable catalyst-type curing agent is preferred because it has excellent rapid curing properties and does not need to consider chemical equivalents.

Examples of the anionic polymerizable or cationic polymerizable catalyst-type curing agent include an imidazole-based curing agent, a hydrazine-based curing agent, a boron trifluoride-amine complex, a sulfonium salt, an amine imine, and a diamine group. Malein, nitrile, melamine and its derivatives, salts of polyamines, dicyandiamide, etc. may also be used. Examples of the addition polymerization-type curing agent include polyamines, polythiols, polyphenols, and acid anhydrides.

When tertiary amines, imidazoles, and the like are used as anionic polymerizable catalyst-type curing agents, the epoxy resin is hardened by heating at an intermediate temperature of about 160 ° C to 200 ° C for about 10 seconds to several hours. . Therefore, the usable life (pot life) can be made longer. As the cationic polymerizable catalyst-type curing agent, for example, a photosensitive onium salt (aromatic diazonium salt, aromatic sulfonium salt, etc.) that hardens the epoxy resin by irradiating energy rays is preferred. In addition, in addition to irradiating energy rays, the epoxy resin is activated by heating to harden the epoxy resin, and there are aliphatic sulfonium salts and the like. Such a hardening agent is preferred because it has the characteristics of rapid hardening.

These latent hardeners can be coated with microencapsulated hardeners by coating polymer materials such as polyurethane and polyester, metal films such as nickel and copper, and inorganic substances such as calcium silicate. It is better to extend the service life. The compounding amount of the latent hardener contained in the first composition is preferably 100 parts by mass, preferably 20 parts by mass to 80 parts by mass, and more preferably 30 parts by mass with respect to the total of 100 parts by mass of the epoxy resin and the film forming material prepared as needed. ~ 70 parts by mass.

The radically polymerizable substance contained in the second composition is a substance having a functional group polymerized by a radical. Examples of such a radical polymerizable substance include an acrylate (also includes a corresponding methacrylate. The same applies hereinafter) a compound, an acryloxy group (also includes a corresponding methacrylic oxy group. The same applies below), and Maleimide compounds, citraconimide resins, nadipine imine resins, etc. The radical polymerizable substance may be used in the state of a monomer or an oligomer, and a monomer and an oligomer may be used in combination. Specific examples of the acrylate compound include methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, and trimethylol. Propane triacrylate, tetramethylolmethane tetraacrylate, 2-hydroxy-1,3-dipropenyloxypropane, 2,2-bis [4- (propyleneoxymethoxy) phenyl] propane , 2,2-bis [4- (propenyloxypolyethoxy) phenyl] propane, dicyclopentenyl acrylate, tricyclodecyl acrylate, tris (isopropenyloxyethyl) isocyanurate Esters, urethane acrylates, and the like. These can be used alone or in combination of two or more. In addition, if necessary, polymerization inhibitors such as hydroquinone and hydroquinone methyl ethers may be suitably used. In addition, from the viewpoint of improving heat resistance, the acrylate compound preferably has at least one substituent selected from the group consisting of a dicyclopentenyl group, a tricyclodecyl group, and a triazine ring. As the radically polymerizable substance other than the acrylate compound, for example, a compound described in International Publication No. 2009/063827 can be suitably used. These can be used alone or in combination of two or more.

Moreover, among the said radically polymerizable substance, the radically polymerizable substance which has a phosphate ester structure represented by following formula (I) is preferable. In this case, since the bonding strength with respect to the surface of an inorganic substance such as a metal is improved, it is suitable for bonding circuit electrodes to each other.

[Chemical 1] [Wherein n represents an integer of 1 to 3]

A radical polymerizable substance having a phosphate structure can be obtained by reacting phosphoric anhydride with 2-hydroxyethyl (meth) acrylate. Specific examples of the radical polymerizable substance having a phosphate structure include mono (2-methacryloxyethyl) phosphate, bis (2-methacryloxyethyl) phosphate, and the like. These can be used alone or in combination of two or more.

The blending amount of the radical polymerizable substance having a phosphate ester structure represented by the formula (I) is preferably 0.01 to 50 parts by mass with respect to a total of 100 parts by mass of the total amount of the radical polymer substance and the film-forming material to be formulated. Part by mass, more preferably 0.5 to 5 parts by mass.

The radical polymerizable substance may be used in combination with allyl acrylate. In this case, the blending amount of allyl acrylate is preferably 0.1 to 10 parts by mass, and more preferably 0.5 to parts by mass based on 100 parts by mass of the total of the radically polymerizable substance and the film-forming material to be blended as necessary. 5 parts by mass.

The curing agent contained in the second composition that generates free radicals upon heating is a curing agent that decomposes upon heating and generates free radicals. Examples of such a curing agent include peroxides and azo compounds. Such a hardening agent can be appropriately selected according to the target connection temperature, connection time, lifespan, and the like. From the viewpoint of high reactivity and an improvement in the lifespan, an organic peroxide having a 10-hour half-life temperature of 40 ° C. or more and a 1-minute half-life temperature of 180 ° C. or less is more preferred, and a 10-hour half-life temperature An organic peroxide having a temperature of 60 ° C. or higher and a half-life of 1 minute of 170 ° C. or lower.

Regarding the blending amount of the hardener, when the connection time is 25 seconds or less, it is preferably 2 parts by mass to 100 parts by mass of the total of the radically polymerizable substance and the film-forming material to be blended as necessary. 10 parts by mass, more preferably 4 to 8 parts by mass. Thereby, a sufficient response rate can be obtained. In addition, the blending amount of the curing agent when the connection time is not limited is preferably 0.05 to 20 parts by mass relative to 100 parts by mass of the total of the radically polymerizable substance and the film forming material to be blended as necessary. More preferably, it is 0.1 to 10 parts by mass.

Specific examples of the curing agent contained in the second composition that generates free radicals upon heating include dioxinyl peroxide, dicarbonate peroxide, peroxyester ketal peroxide, and dioxane peroxide. Radicals, hydrogen peroxide, silane-based peroxides, and the like. From the viewpoint of suppressing the corrosion of the circuit electrode, a hardener containing a chloride ion and an organic acid at a concentration of 5,000 ppm or less is preferred, and more preferably, a less organic acid is generated after thermal decomposition. hardener. Specific examples of such a curing agent include peroxide esters, dialkyl peroxides, hydrogen peroxide, silane-based peroxides, and the like, and more preferably a hardener selected from among peroxide esters having high reactivity. . Moreover, the said hardening | curing agent can be used suitably for mixing.

Examples of the peroxyester include cumyl peroxyneodecanoate, 1,1,3,3-tetramethylbutyl neodecanoate, and 1-cyclohexyl-1-methyl peroxydecanoate Ethyl ester, tert-hexyl peroxydecanoate, tert-butyl pervalvalate, 1,1-, 3,3-tetramethylbutyl peroxy 2-ethylhexanoate, 2,5-di Methyl-2,5-bis (2-ethylhexylperoxy) hexane, 2-ethylhexanoate 1-cyclohexyl-1-methylethyl peroxide, 2-ethyl peroxide Tert-hexyl hexanoate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxyisobutyrate, 1,1-bis (third butylperoxy) cyclohexane, Isopropyl peroxy monohexyl carbonate, tert-butyl peroxy-3,5,5-trimethylhexanoate, tert-butyl peroxylaurate, 2,5-dimethyl-2, 5-Di (m-toluenylperoxy) hexane, third butyl peroxy isopropyl monocarbonate, third butyl peroxy-2-ethylhexyl monocarbonate, third peroxybenzoic acid Hexyl ester, tert-butyl peroxyacetate, and the like. As the hardener that generates free radicals by heating other than the peroxide ester, for example, a compound described in International Publication No. 2009/063827 can be suitably used. These can be used alone or in combination of two or more.

These hardening agents may be used alone or as a mixture of two or more kinds, and further, a decomposition accelerator, a decomposition inhibitor, or the like may be used in combination. In addition, these hardeners may be coated with a polyurethane-based or polyester-based polymer material to perform microencapsulation. Microencapsulated hardeners are preferred because they prolong life.

In the circuit connection material of this embodiment, a film-forming material may be added and used if necessary. The so-called film-forming material is such that when a liquid substance is solidified and the constituent composition is formed into a film shape, it is easy to handle the film in a normal state (normal temperature and pressure), and it is not easy to crack. , Mechanical properties such as crushing or sticking are imparted to the film. Examples of the film forming material include phenoxy resin, polyvinyl formal resin, polystyrene resin, polyvinyl butyral resin, polyester resin, polyamide resin, xylene resin, and polyurethane. Ester resin, etc. Among these, a phenoxy resin is preferable since it is excellent in adhesiveness, compatibility, heat resistance, and mechanical strength.

The phenoxy resin is a resin obtained by reacting a bifunctional phenol with an epihalohydrin until polymerization occurs, or by addition-polymerizing a bifunctional epoxy resin with a bifunctional phenol. The phenoxy resin can be obtained by, for example, mixing 1 mol bifunctional phenols and 0.985 mol to 1.015 mol epihalohydrin in the presence of a catalyst such as an alkali metal hydroxide, in a non-reactive solvent, at It was obtained by performing a reaction at a temperature of 120 ° C. In addition, as the phenoxy resin, from the viewpoint of the mechanical properties and the thermal properties of the resin, it is particularly preferable that the blending equivalent ratio of the bifunctional epoxy resin and the bifunctional phenols is epoxy group / phenolic hydroxyl group = 1 / 0.9 ～ 1 / 1.1, in the presence of catalysts such as alkali metal compounds, organophosphorus compounds, cyclic amine compounds, etc., amines, ethers, ketones, lactones with a boiling point of 120 ° C or higher In an organic solvent such as alcohol or alcohol, it is obtained by heating to 50 ° C. to 200 ° C. under a condition that the reaction solid content is 50% by mass or less. The phenoxy resin may be used alone or as a mixture of two or more.

Examples of the bifunctional epoxy resin include bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol AD epoxy resin, bisphenol S epoxy resin, and biphenyl diglycidyl ether. , Methyl substituted biphenyl diglycidyl ether and the like. Bifunctional phenols are compounds having two phenolic hydroxyl groups. Examples of bifunctional phenols include hydroquinones, bisphenol A, bisphenol F, bisphenol AD, bisphenol S, bisphenol fluorene, methyl-substituted bisphenol fluorene, dihydroxybiphenyl, methyl Substituted bisphenols such as dihydroxybiphenyl. The phenoxy resin can also be modified by radical polymerizable functional groups or other reactive compounds (such as epoxy modification).

When the total mass of the circuit connection material is 100 parts by mass, the blending amount of the film-forming material is preferably from 10 to 90 parts by mass, and more preferably from 20 to 60 parts by mass.

The circuit connection material according to this embodiment may further contain a polymer or copolymer containing at least one of acrylic acid, acrylate, methacrylate, and acrylonitrile as a monomer component. Here, in terms of excellent stress relaxation, the circuit connecting material is preferably used in combination and includes a copolymer acrylic rubber containing glycidyl acrylate and / or a methyl group containing a glycidyl ether group. Glycidyl acrylate. In terms of improving the cohesiveness of the adhesive composition, the weight average molecular weight of these acrylic rubbers is preferably 200,000 or more. The circuit connection material of this embodiment may further contain rubber particles, fillers, softeners, accelerators, anti-aging agents, colorants, flame retardants, thixotropic agents, coupling agents, phenol resins, melamine resins, and isocyanates. Wait.

The rubber fine particles are preferably particles having an average particle diameter of less than twice the average particle diameter of the conductive particles to be blended, and a storage elastic coefficient at room temperature (25 ° C) of room temperature of the conductive particles and the adhesive composition at room temperature. The storage elasticity coefficient is less than 1/2. In particular, the material of the rubber particles is silicone, acrylic emulsion, Styrene Butadiene Rubber (SBR), Nitrile-Butadiene Rubber (NBR), or polybutadiene rubber. In the case of a mixture, it is suitable to use it alone or as a mixture of two or more kinds. These three-dimensionally crosslinked rubber fine particles are excellent in solvent resistance and are easily dispersed in an adhesive composition.

The filler can improve connection reliability of electrical characteristics between circuit electrodes. As the filler, for example, one whose average particle diameter is 1/2 or less of the average particle diameter of the conductive particles can be suitably used. In addition, in a case where particles having no conductivity are used in combination, as long as they are equal to or smaller than the average particle diameter of the particles having no conductivity, they can be used. The blending amount of the filler is preferably 5 to 60 parts by mass based on 100 parts by mass of the adhesive composition. When the blending amount is 60 parts by mass or less, there is a tendency that the effect of improving the reliability of the connection can be more fully obtained. On the other hand, when it is 5 parts by mass or more, the additive effect of the filler tends to be sufficiently obtained. .

As the coupling agent, a compound containing an amine group, a vinyl group, an acrylic fluorenyl group, an epoxy group, or an isocyanate group is preferred because the adhesion is improved.

The circuit connection material is a material that is melt-flowed at the time of connection to obtain the connection of the opposite circuit electrodes, and then is hardened to maintain the connection. The fluidity of the circuit connection material is an important factor. As an index which shows the said situation, the following is mentioned, for example. That is, a 5 mm × 5 mm circuit connection material having a thickness of 35 μm was sandwiched between two glass plates of 15 mm × 15 mm having a thickness of 0.7 mm, and the conditions were performed at 170 ° C., 2 MPa, and 10 seconds. In the case of heat and pressure, the fluidity (B) / (A) expressed by the area (A) of the main surface of the circuit connection material before heat and pressure and the area (B) of the main surface after heat and pressure are used. The value is preferably 1.3 to 3.0, and more preferably 1.5 to 2.5. If it is 1.3 or more, there is a tendency that the fluidity is appropriate and a good connection is easy to obtain, and if it is 3.0 or less, bubbles are less likely to occur and the reliability is more excellent.

The elastic coefficient at 40 ° C. of the circuit connection material after curing is preferably 100 MPa to 3000 MPa, and more preferably 500 MPa to 2000 MPa. The elastic coefficient of the hardened circuit connection material can be measured using, for example, a dynamic viscoelasticity measuring device (Dynamic Viscoelastic Analyzer (DVE), Dynamic Mechanical Analyzer (DMA), etc.).

The circuit connection material of this embodiment can be suitably used for chip on glass (COG) connection, flexible on board (FOB) connection, and flexible on glass (FOG) connection. Connection, Flex on Flex (FOF) connection, Flex on Polymer (FOP) connection on polymer substrate, Chip on Polymer (COP) connection on polymer substrate, flexibility Chip on Flex (COF) connection, etc.

The so-called COG connection is, for example, a method of connecting an IC to an organic EL panel or a liquid crystal display (LCD) panel, which refers to a circuit electrode formed on the IC and a glass substrate forming the organic EL panel or LCD panel. Connection of circuit electrodes. The FOB connection refers to, for example, a connection between a circuit electrode formed on a flexible substrate and a circuit electrode formed on a printed wiring board represented by a tape carrier package (TCP), COF, and FPC. The FOG connection refers to a connection between a circuit electrode formed on a flexible substrate and a circuit electrode formed on a glass substrate constituting an organic EL panel or an LCD panel, such as TCP, COF, and FPC. The FOF connection refers to a connection between a circuit electrode formed on a flexible substrate and a circuit electrode formed on a flexible substrate, such as TCP, COF, and FPC. The FOP connection refers to a connection between a circuit electrode formed on a flexible substrate and a circuit electrode formed on a polymer substrate constituting an organic EL panel or an LCD panel. The COP connection refers to a connection between a circuit electrode formed on an IC and a circuit electrode formed on a plastic substrate. The COF connection refers to a connection between a circuit electrode formed on an IC and a circuit electrode formed on a flexible substrate.

<Connection Structure> The circuit connection structure of this embodiment includes a first circuit member having a first circuit electrode, a second circuit member having a second circuit electrode, and a first circuit member and a second circuit member interposed therebetween. The connection part between the hardened | cured material containing the said circuit connection material. In this embodiment, as the material of the circuit electrode, Ti, Al, Mo, Co, Cu, Cr, Sn, Zn, Ga, In, Ni, Au, Ag, V, Sb, Bi, Re, Ta, Nb can be used. , W, etc. From the viewpoint of achieving a balance between connection resistance and price, the thickness of the circuit electrode is preferably 100 nm to 5000 nm, and more preferably 100 nm to 2500 nm. In addition, the lower limit may be set to 500 nm.

The circuit connection structure of this embodiment can be produced by a method in which a first circuit member having a first circuit electrode and a second circuit member having a second circuit electrode face each other with the first circuit electrode facing the second circuit electrode. It is configured in such a manner that the circuit connection material is interposed between the first circuit electrode and the second circuit electrode disposed oppositely, and is heated and pressurized, so that the first circuit electrode and the second circuit electrode are electrically connected. As such, the circuit connection material of this embodiment is useful as a material for bonding electrical circuits to each other.

More specifically, examples of the circuit member include wafer components such as a semiconductor wafer, a resistor wafer, and a capacitor wafer; and substrates such as a printed circuit board. A plurality (or a single case) of the circuit electrodes are usually provided in the circuit components. At least a part of the circuit electrodes are arranged facing each other, and the circuit connection material is interposed between the circuit electrodes arranged facing each other, and at least one set of circuit members is heated and pressurized, thereby the opposedly arranged circuit electrodes are mutually opposed. Electrical connection. At this time, the circuit electrodes arranged opposite to each other are electrically connected via the conductive particles included in the circuit connection material, and on the other hand, adjacent circuit electrodes are kept insulated from each other. As such, the circuit connection material of this embodiment shows anisotropic conductivity.

3 (a) to 3 (c), an embodiment of a method of manufacturing a circuit connection structure will be described. FIG. 3 (a) is a cross-sectional view of a step before connecting circuit components to each other, FIG. 3 (b) is a cross-sectional view of a step when connecting circuit components to each other, and FIG. 3 (c) is a cross-sectional view of a step after connecting circuit components to each other .

First, as shown in FIG. 3 (a), a circuit member 20 provided with a circuit electrode 21 a and a circuit substrate 21 b on the organic EL panel 21, and a circuit member 30 provided with a circuit electrode 31 a on the substrate 31 are prepared. Then, the circuit connection material 5 formed into a film shape is placed on the circuit electrode 21a.

Next, as shown in FIG. 3 (b), the substrate 31 on which the circuit electrode 31a is provided is aligned on the circuit electrode 21a and the circuit electrode 31a so as to face each other, and is placed on the circuit connection material 5 to make the circuit The connection material 5 is interposed between the circuit electrode 21a and the circuit electrode 31a. In addition, the circuit electrode 21a and the circuit electrode 31a have a structure (not shown) in which a plurality of electrodes are arranged side by side in the depth direction. Since the circuit connection material 5 has a film shape, it is easy to handle. Therefore, the circuit connection material 5 can be easily interposed between the circuit electrode 21a and the circuit electrode 31a, and the connection operation of the circuit member 20 and the circuit member 30 can be easily performed.

Then, the circuit connection material 5 is pressurized in the direction of arrow A in FIG. 3 (b) through the organic EL panel 21 and the substrate 31 while being heated while being hardened. Thereby, as shown in FIG.3 (c), the circuit connection structure 50 in which the circuit member 20 and the circuit member 30 were connected via the hardened | cured material 5a of the circuit connection material was obtained. As a method of the hardening treatment, one or both of heating and light irradiation may be adopted depending on the adhesive composition to be used. [Example]

Hereinafter, the present disclosure will be specifically described with examples. However, the present invention is not limited to these examples.

(1) Preparation of conductive particles Eleven conductive particles A to K shown in Table 1 below were prepared. These conductive particles are core-shell particles including a core containing plastic particles and a metal layer (nickel layer) covered with the core particles as a shell. The electrical conductivity of nickel is 14.5 × 10 ⁶ S / m. Among conductive particles A to K, conductive particles A to E, conductive particles H, and conductive particles J satisfy both the first condition and the second condition.

[Table 1]

<Example 1> (2) Production of anisotropic conductive film (preparation of phenoxy resin solution) 50 g of phenoxy resin (product name: PKHC, manufactured by Union Carbide Co., Ltd.) was weight averaged. Molecular weight 5000) was dissolved in a mixed solution of toluene / ethyl acetate = 50/50 (mass ratio) to prepare a phenoxy resin solution having a solid content of 40% by mass.

(Synthesis of Acrylic Urethane) To a 2 L (liter) four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet, and a reflux cooler was added polycarbonate diol (Aldrich) The reaction solution was prepared by a company with a number average molecular weight Mn = 2000) of 4000 parts by mass, 238 parts by mass of 2-hydroxyethyl acrylate, 0.49 parts by mass of hydroquinone monomethyl ether, and 4.9 parts by mass of a tin-based catalyst. For the reaction solution heated to 70 ° C., 666 parts by mass of isophorone diisocyanate (IPDI) was added dropwise uniformly over 3 hours to cause a reaction. After completion of the dropwise addition, the reaction was continued for 15 hours, and the time when the NCO% (NCO content) became 0.2% by mass or less was regarded as the end of the reaction to obtain an acrylic urethane. NCO% was confirmed with a potential difference automatic titration device (trade name: AT-510, manufactured by Kyoto Electronics Industry Co., Ltd.). As a result of Gel Permeation Chromatography (GPC) analysis, the weight average molecular weight of the acrylic urethane was 8,500 (standard polystyrene conversion value). Table 2 shows the measurement conditions of GPC.

[Table 2]

(Preparation of Adhesive Composition Containing Liquid) The phenoxy resin solution weighed out from the phenoxy resin solution so as to contain 50 g of solid content, the acrylic urethane 30 g, and isocyanuric acid 15 g of ester acrylate (product name: M-215, manufactured by Toa Synthesis Co., Ltd.), 1 g of phosphate ester acrylate, and benzamidine peroxide as a free radical generator (product name: Naiper ( NYPER) BMT-K40 (manufactured by Nippon Oil Co., Ltd.) 4 g were mixed to prepare an adhesive composition-containing liquid.

(Production of Anisotropic Conductive Film) With respect to 100 parts by mass of the adhesive composition-containing liquid, 5 parts by mass of the conductive particles A were dispersed to prepare a circuit-connecting material-containing liquid. This circuit connection material-containing liquid was applied to a 50 μm-thick polyethylene terephthalate (PET) film having a surface treated on one side using a coating device, and then performed at 70 ° C. 3 minutes hot air drying. Thereby, an anisotropic conductive film having a thickness of 20 μm was obtained on the PET film. When the total mass of the anisotropic conductive film is 100 parts by volume, the contents of the adhesive component and the conductive particles are 97 parts by volume and 3 parts by volume, respectively.

(3) Fabrication of connection structure (electrode outermost surface: titanium) The anisotropic conductive film with a PET film was cut to a predetermined size (width 1.5 mm × length 3 cm). The surface (adhesive surface) on which the anisotropic conductive film was formed was transferred to a glass substrate (thickness 0.7 mm) coated with titanium (film thickness 50 nm) and aluminum (film thickness 250 nm) in this order from the outermost surface. on. The transfer conditions were set at 70 ° C. and 1 MPa for 2 seconds. After the PET film was peeled off, a flexible circuit board (FPC) having 600 tin-plated copper circuits with a pitch of 50 μm and a thickness of 8 μm was temporarily fixed on the anisotropic conductive film. The temporarily fixed conditions were set at 24 ° C. and 0.5 MPa for 1 second. Next, it was installed in a formal crimping device, and a silicone rubber sheet having a thickness of 200 μm was used as a buffer material, and the condition was performed at 170 ° C. and 3 MPa for 6 seconds from a FPC side using a heat tool. Heated and pressurized and connected over a width of 1.5 mm. Thereby, a connection structure is obtained.

(4) Fabrication of connection structure (electrode top surface: ITO) Instead of the glass substrate coated with titanium and aluminum in order from the top surface, a glass substrate coated with ITO (thickness of 100 nm) was used. Except for this, a connection structure was obtained in the same manner as described above.

(5) Fabrication of connection structure (electrode outermost surface: IZO) Instead of the glass substrate sequentially coated with titanium and aluminum from the outermost surface, IZO (film thickness 100 nm) was applied sequentially from the outermost surface. ), Cr (film thickness: 50 nm), and aluminum (film thickness: 200 nm), except for a glass substrate, a connection structure was obtained in the same manner as described above.

(6) Measurement of connection resistance The connection resistance of the two types of connection structures obtained was measured as follows. A multimeter (device name: TR6845, manufactured by Advantest Co., Ltd.) was used to measure the resistance value between adjacent circuits of the FPC including the connection portion of the connection structure. Furthermore, the 40-point resistance between adjacent circuits was measured and the average value was calculated, and this was made into connection resistance. The results are shown in Table 3.

<Examples 2 to 5 and Comparative Examples 1 and 2> In the same manner as in Example 1, except that conductive particles B to K were used instead of conductive particles A, three kinds of connection structures were produced. And measure these connection resistances. The results are shown in Table 3.

[table 3] [Industrial availability]

According to the present disclosure, it is possible to provide a method of selecting conductive particles having sufficiently high versatility with respect to a circuit electrode included in a circuit member to be connected. In addition, according to the present disclosure, it is possible to provide a conductive particle, a circuit connection material using the same, a connection structure, and a method of manufacturing the same.

1, 1a, 1b, 2, 2a, 2b ‧‧‧ conductive particles

3, 4, 20, 30‧‧‧ circuit components

3a, 4a, 21a, 31a ‧‧‧ circuit electrodes

5‧‧‧Circuit connection materials

5a‧‧‧hardened material of circuit connection material

10‧‧‧ connection structure

50‧‧‧Circuit connection structure

21‧‧‧Organic EL Panel

21b‧‧‧circuit board

31‧‧‧ substrate

A‧‧‧arrow

FIG. 1 (a) is a schematic cross-sectional view showing an enlarged connection portion of a connection structure manufactured using conductive particles selected by the method disclosed in the present disclosure, and FIG. 1 (b) shows that the first condition and the second condition are not satisfied when the application is performed The schematic cross-sectional view of the connection part of the connection structure manufactured by the conductive particle of any one is enlarged. FIG. 2 is a graph showing an example of a measurement result of a volume specific resistance. 3 (a) to 3 (c) are cross-sectional views schematically showing an example of a method for manufacturing a connection structure.

Claims (13)

A method for selecting conductive particles, which is a method for selecting conductive particles, comprising: a step of determining whether the metal constituting the outermost layer of the conductive particles satisfies the following first condition, and a step of determining whether the conductive particles meet the following second condition, The conductive particles satisfying both the first condition and the second condition are judged to be good; the first condition: the conductivity at 20 ° C is 40 × 10 ⁶ S / m or less; the second condition: a load of 2 kN The volume specific resistance at this time is 15 mΩcm or less. A circuit connecting material is used for adhering circuit members to each other and electrically connecting circuit electrodes of each circuit member to each other, and includes an adhesive component hardened by light or heat, and dispersed in the adhesive. The conductive particles in the agent component are conductive particles determined to be good by the method for selecting conductive particles as described in item 1 of the scope of patent application. The circuit connection material according to item 2 of the patent application scope is formed into a film. The circuit connection material according to item 2 or item 3 of the scope of patent application, wherein the connection is a wafer-on-glass connection, a flexible substrate connection on a substrate, a flexible substrate connection on a glass, a flexible substrate on a flexible substrate Connection, flexible substrate connection on polymer substrate, wafer connection on polymer substrate or wafer connection on flexible substrate. A method for manufacturing a connection structure, comprising: a step of interposing a circuit connection material according to any one of claims 2 to 4 of a patent application range between a pair of circuit members arranged in opposition, and borrowing A hardened body containing the circuit connection material is formed by heating and pressurization, and is interposed between the pair of circuit members, and the circuit is electrically connected to the circuit electrodes of the circuit members. A step of connecting the components to each other. A connection structure including: a pair of circuit members arranged oppositely; and a connection portion including a hardened object of the circuit connection material according to any one of claims 2 to 4 of the patent application scope, and interposed therebetween Between the pair of circuit members, the circuit members are adhered to each other such that the circuit electrodes of the circuit members are electrically connected to each other. A conductive particle having a metal layer having a conductivity of 40 × 10 ⁶ S / m or less at 20 ° C. and a volume specific resistance of 15 mΩcm or less when a load of 2 kN is applied. The conductive particle according to item 7 of the scope of patent application, wherein the metal layer includes Ni. The conductive particle according to item 7 or item 8 of the patent application scope further includes core particles including a resin material, and the metal layer is formed on a surface of the core particle. The conductive particle according to any one of claims 7 to 9, wherein the metal layer has protrusions. The conductive particle according to any one of claims 7 to 10 in the scope of the patent application, further comprising: an organic film, an organic fine particle, or an inorganic fine particle arranged on the surface of the metal layer. The conductive particle according to any one of items 7 to 11 of the scope of patent application, wherein the average particle diameter is 1 μm to 50 μm. The conductive particle according to any one of items 7 to 12 of the scope of application for a patent, wherein the elastic coefficient at a compression of 20% is 0.1 GPa to 15 GPa.