JP6212366B2 - Conductive particles, conductive materials, and connection structures - Google Patents

Description

  The present invention relates to a conductive particle in which a conductive portion is disposed on the surface of a base particle and has a plurality of protrusions on the outer surface of the conductive portion. The present invention also relates to a conductive material and a connection structure using the conductive particles.

  Anisotropic conductive materials such as anisotropic conductive pastes and anisotropic conductive films are widely known. In these anisotropic conductive materials, conductive particles are dispersed in a binder resin.

  In order to obtain various connection structures, for example, the anisotropic conductive material may be connected between electrodes of a flexible printed circuit board and a glass substrate (FOG (Film on Glass)), an electrode of a semiconductor chip and a flexible printed circuit board. Connection (COF (Chip on Film)), connection between electrodes of a semiconductor chip and a glass substrate (COG (Chip on Glass)), and connection between electrodes of a flexible printed circuit board and a glass epoxy substrate (FOB (Film)) on Board)) and the like.

  An organic electroluminescence (hereinafter sometimes referred to as organic EL) display element has a stacked structure in which an organic light emitting material layer is sandwiched between a pair of electrodes corresponding to each other. When electrons are injected from one electrode into the organic light emitting material layer and holes are injected from the other electrode, electrons and holes are combined in the organic light emitting material layer to emit light. Since the organic EL display element emits light by itself, the organic EL display element has better visibility than a liquid crystal display element that requires a backlight, can be reduced in thickness, and can be driven with a low DC voltage. Has the advantage. In an organic EL display element, a titanium electrode (titanium wiring) is often used as an electrode (wiring).

  An oxide film may be formed on the surfaces of the electrode and the conductive particles. In order to break through the oxide film and reduce the connection resistance between the electrodes, conductive particles having protrusions on the conductive surface are used.

  As an example of the conductive particles, the following Patent Document 1 discloses a conductive material in which a nickel conductive layer or a nickel alloy conductive layer is formed on the surface of spherical base particles having an average particle diameter of 1 to 20 μm by an electroless plating method. Sex particles are disclosed. The conductive particles have minute protrusions of 0.05 to 4 μm on the outermost layer of the conductive layer. The conductive layer and the protrusion are substantially continuously connected.

JP 2000-243132 A

  When the conventional conductive particles having protrusions on the conductive surface as described in Patent Document 1 are used to electrically connect the electrodes including the titanium electrode, the conductive particles are formed on the surface of the titanium electrode. There is a problem that the connection resistance between the electrodes is lowered without sufficiently breaking through the oxide film. Conventional conductive particles have a problem that even if the connection resistance between electrodes such as an ITO electrode can be reduced, the connection resistance between electrodes including a titanium electrode cannot be sufficiently reduced.

  The objective of this invention is providing the electroconductive particle which can make connection resistance low, when the electrodes containing a titanium electrode are electrically connected.

According to a wide aspect of the present invention, there are conductive particles used for electrical connection of a titanium electrode, having a conductive portion on at least a surface, the conductive portion having a plurality of protrusions on the surface, and 10% compressive modulus when compressed is at 9000 N / mm ² or more and compression modulus when compressed 20% 8000 N / mm ² or more, the compression modulus of 7000N / mm when compressed 30% ^The electroconductive particle which is ² or more and a compression recovery rate is 60% or more and 90% or less is provided.

  On the specific situation with the electroconductive particle which concerns on this invention, the said electroconductive particle is equipped with the base material particle and the said electroconductive part arrange | positioned on the surface of the said base material particle.

  On the specific situation with the electroconductive particle which concerns on this invention, the height of the said protrusion is 1/100 or more of the particle diameter of electroconductive particle.

  On the specific situation with the electroconductive particle which concerns on this invention, it has the some core substance which has raised the surface of the said electroconductive part so that the said some protrusion may be formed in the said electroconductive part.

  The Mohs hardness of the material of the core substance is preferably equal to or greater than the Mohs hardness of the material of the conductive part, and more preferably larger than the Mohs hardness of the material of the conductive part.

  On the specific situation with the electroconductive particle which concerns on this invention, a particle diameter is 1 micrometer or more and 4 micrometers or less.

  On the specific situation with the electroconductive particle which concerns on this invention, the electroconductive material containing the electroconductive particle mentioned above and binder resin is provided.

  According to a wide aspect of the present invention, a first connection target member having a first electrode on the surface, a second connection target member having a second electrode on the surface, the first connection target member, A connection portion connecting the second connection target member, and the connection portion is formed of the conductive particles described above or formed of a conductive material including the conductive particles and a binder resin. And at least one of the first electrode and the second electrode is a titanium electrode, and the first electrode and the second electrode are electrically connected by the conductive particles. A connection structure is provided.

The conductive particles according to the present invention have at least a conductive portion on the surface, the conductive portion has a plurality of protrusions on the surface, and a compressive elastic modulus when the conductive particles are compressed by 10% is 9000 N / mm ^2. The compression elastic modulus when compressed by 20% is 8000 N / mm ² or more, the compression elastic modulus when compressed by 30% is 7000 N / mm ² or more, and the compression recovery rate of the conductive particles Therefore, when the conductive particles according to the present invention are used to electrically connect the electrodes including the titanium electrode, the connection resistance between the electrodes can be lowered.

FIG. 1 is a cross-sectional view showing conductive particles according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing conductive particles according to the second embodiment of the present invention. FIG. 3 is a cross-sectional view showing conductive particles according to the third embodiment of the present invention. FIG. 4 is a cross-sectional view schematically showing a connection structure using conductive particles according to the first embodiment of the present invention.

  Details of the present invention will be described below.

(Conductive particles)
The electroconductive particle which concerns on this invention is used for the electrical connection of a titanium electrode. The electroconductive particle which concerns on this invention has an electroconductive part at least on the surface. In the conductive particles according to the present invention, the conductive portion has a plurality of protrusions on the surface. When the conductive particles according to the present invention are compressed by 10%, the compression elastic modulus (10% K value) is 9000 N / mm ² or more, and when the conductive particles are compressed by 20%, the compression elastic modulus (20% K value) is It is 8000 N / mm ² or more, and the compression elastic modulus (30% K value) when compressed by 30% is 7000 N / mm ² or more. The compression recovery rate of the conductive particles according to the present invention is 60% or more and 90% or less.

  A thick oxide film is present on the surface of the titanium electrode as compared with the surface of the ITO electrode. For this reason, in order to sufficiently reduce the connection resistance between the electrodes including the titanium electrode, it is necessary that the conductive particles break through the thick oxide film. However, the conventional conductive particles have a problem that it is difficult to sufficiently penetrate the thick oxide film on the titanium electrode, and as a result, it is difficult to sufficiently reduce the connection resistance.

  On the other hand, by adopting the above-described configuration in the conductive particles according to the present invention, even when the electrodes including the titanium electrode are electrically connected, the thick oxide film can be sufficiently broken by the protrusion. The connection resistance between the electrodes can be lowered. In the present invention, in order to reduce the connection resistance between the electrodes, the 10% K value, 20% K value, and 30% K value of the conductive particles are set to be considerably high. In the present invention, since the compression recovery rate is also relatively high, the connection resistance between the electrodes is effectively reduced.

In order to reduce the connection resistance and increase the connection reliability between the electrodes, the compression elastic modulus (10% K value) when the conductive particles are compressed by 10% is 9000 N / mm ² or more. From the viewpoint of further reducing the connection resistance, the 10% K value is preferably 10,000 N / mm ² or more, more preferably 13000 N / mm ² or more. The upper limit of the 10% K value is not particularly limited, but the 10% K value is preferably 20000 N / mm ² or less.

In order to reduce the connection resistance and increase the connection reliability between the electrodes, the compression elastic modulus (20% K value) when the conductive particles are compressed by 20% is 8000 N / mm ² or more. From the viewpoint of further reducing the connection resistance, the 20% K value is preferably 9000 N / mm ² or more, more preferably 12000 N / mm ² or more. The upper limit of the 20% K value is not particularly limited, but the 20% K value is preferably 19000 N / mm ² or less.

In order to reduce the connection resistance and increase the connection reliability between the electrodes, the compression elastic modulus (30% K value) when the conductive particles are compressed by 30% is 7000 N / mm ² or more. From the viewpoint of further lowering the connection resistance, the 30% K value is preferably 8000 N / mm ² or more, more preferably 11000N / mm ² or more. The upper limit of the 30% K value is not particularly limited, but the 30% K value is preferably 18000 N / mm ² or less.

  The compression elastic modulus (10% K value, 20% K value, or 30% K value) of the conductive particles can be measured as follows.

  Using a micro-compression tester, the conductive particles are compressed under the conditions of 25 ° C., compression speed of 0.3 mN / sec, and maximum test load of 20 mN on the end face of a cylindrical indenter (diameter: 100 μm, made of diamond). The load value (N) and compression displacement (mm) at this time are measured. From the measured value obtained, the compression elastic modulus can be obtained by the following formula. As the micro compression tester, for example, “Fischer Scope H-100” manufactured by Fischer is used.

10% K value, 20% K value or 30% K value (N / mm ² ) = (3/2 ^1/2 ) · F · S ⁻³ / ² · R ^−1/2
F: Load value when the conductive particles are 10%, 20% or 30% compressively deformed (N)
S: Compression displacement (mm) when conductive particles are 10%, 20% or 30% compressively deformed
R: radius of conductive particles (mm)

  In order to reduce the connection resistance, the compression recovery rate of the conductive particles is 60% or more and 90% or less. From the viewpoint of further reducing the connection resistance, the compression recovery rate of the conductive particles is preferably 65% or more, more preferably 70% or more, preferably 85% or less, and more preferably 80% or less.

  The compression recovery rate can be measured as follows.

  Spread conductive particles on the sample stage. With respect to one dispersed conductive particle, a load (reversal load value) is applied to the central direction of the conductive particle at 25 ° C. until the conductive particle is compressed and deformed by 30% at 25 ° C. Thereafter, unloading is performed up to the origin load value (0.40 mN). The load-compression displacement during this period is measured, and the compression recovery rate can be obtained from the following equation. The load speed is 0.33 mN / sec. As the micro compression tester, for example, “Fischer Scope H-100” manufactured by Fischer is used.

Compression recovery rate (%) = [(L1-L2) / L1] × 100
L1: Compression displacement from the load value for origin to the reverse load value when applying a load L2: Unloading displacement from the reverse load value to the load value for origin when releasing the load

  Hereinafter, the present invention will be clarified by describing specific embodiments and examples of the present invention with reference to the drawings.

  FIG. 1 is a cross-sectional view showing conductive particles according to the first embodiment of the present invention.

  The electroconductive particle 1 shown in FIG. 1 has the base particle 2 and the electroconductive part 3 arrange | positioned on the surface of the base particle 2. As shown in FIG. In the conductive particles 1, the conductive part 3 is a conductive layer. The conductive part 3 covers the surface of the base particle 2. The conductive particle 1 is a coated particle in which the surface of the base particle 2 is coated with the conductive portion 3.

  The said electroconductive particle should just have an electroconductive part on the surface at least. Like the electroconductive particle 1, the center part may differ from the electroconductive part in the base material particle | grains. The entirety of the conductive particles may be a conductive portion. The whole conductive particle may be formed of the same metal species.

  The conductive particle 1 has a protrusion 1a on the conductive surface. The conductive portion 3 has a protrusion 3a on the surface (the outer surface of the conductive layer).

  The conductive particle 1 has a plurality of core substances 4 on the surface of the base particle 2. The conductive portion 3 covers the base particle 2 and the core substance 4. By covering the core material 4 with the conductive portion 3, the conductive particles 1 have a plurality of protrusions 1a on the surface. The surface of the conductive portion 3 is raised by the core material 4, and a plurality of protrusions 1 a and 3 a are formed. The conductive particles 1 include a plurality of core substances 4 that have raised the surface of the conductive portion 3 so as to form a plurality of protrusions 1 a and 3 a inside the plurality of protrusions 1 a and 3 a in the conductive portion 3. Have.

  FIG. 2 is a cross-sectional view showing conductive particles according to the second embodiment of the present invention.

  A conductive particle 1 </ b> A shown in FIG. 2 has a base particle 2 and a conductive part 3 </ b> A disposed on the surface of the base particle 2. The conductive portion 3A is a conductive layer. Only the presence or absence of the core substance 4 is different between the conductive particles 1 and the conductive particles 1A. The conductive particles 1A do not have a core substance.

  The conductive particles 1A have protrusions 1Aa on the conductive surface. The conductive portion 3A has a protrusion 3Aa on the surface (the outer surface of the conductive layer).

  The conductive portion 3A has a first portion and a second portion that is thicker than the first portion. Accordingly, the conductive portion 3A has a protrusion 3Aa on the surface (the outer surface of the conductive layer). A portion excluding the plurality of protrusions 1Aa and 3Aa is the first portion of the conductive portion 3A. The plurality of protrusions 1Aa and 3Aa are the second portions where the thickness of the conductive portion 3A is thick.

  In order to form the protrusions 1Aa and 3Aa like the conductive particles 1A, it is not always necessary to use a core substance.

  FIG. 3 is a cross-sectional view showing conductive particles according to the third embodiment of the present invention.

  A conductive particle 1 </ b> B illustrated in FIG. 3 includes a base particle 2 and a conductive portion 3 </ b> B disposed on the surface of the base particle 2. The conductive part 3B is a conductive layer. The conductive part 3B has a first conductive part 3Bx disposed on the surface of the base particle 2 and a second conductive part 3By disposed on the surface of the first conductive part 3Bx.

  The conductive particles 1B have protrusions 1Ba on the conductive surface. The conductive particles 1B have protrusions 1Ba on the surface. The conductive portion 3B has a protrusion 3Ba on the surface (the outer surface of the conductive layer). The conductive particle 1B has a plurality of core substances 4 on the surface of the first conductive portion 3Bx. The second conductive portion 3By covers the first conductive portion 3Bx and the core substance 4. The base particle 2 and the core substance 4 are arranged with a space therebetween. Between the base material particle 2 and the core substance 4, there is a first conductive portion 3Bx. By covering the core material 4 with the second conductive portion 3By, the conductive portion 3B has a plurality of protrusions 3Ba on the surface. The surfaces of the conductive portion 3B and the second conductive portion 3By are raised by the core material 4, and a plurality of protrusions 3Ba are formed.

  Like the conductive particles 1B, the conductive portion 3B may have a multilayer structure. Further, in order to form the protrusions 1Ba and 3Ba, the core material 4 is disposed on the first conductive portion 3Bx of the inner layer, and the core material 4 and the first conductive portion 3Bx are separated by the second conductive portion 3By of the outer layer. It may be coated.

  The compression elastic modulus (10% K value, 20% K value, and 30% K value) and the compression recovery rate of the conductive particles 1, 1A, 1B described above are within the above-described range.

  Hereinafter, other details of the conductive particles will be described.

  The particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 500 μm or less, more preferably 100 μm or less, still more preferably 50 μm or less, particularly preferably 20 μm or less, and most preferably 4 μm or less. It is. When the particle diameter of the conductive particles is not less than the above lower limit and not more than the above upper limit, the contact area between the conductive particles and the electrode becomes sufficiently large when the electrodes are connected using the conductive particles, and the conductive part When forming the conductive particles, it becomes difficult to form aggregated conductive particles. Further, the distance between the electrodes connected via the conductive particles does not become too large, and the conductive layer is difficult to peel from the surface of the base material particles.

  The particle diameter of the conductive particles is particularly preferably 1 μm or more and 4 μm or less. When the particle diameter of the conductive particles is 1 μm or more and 4 μm or less, the connection resistance between the electrodes can be effectively reduced when the electrodes including the titanium electrode are electrically connected. When the line (L) where the electrode is formed and the space (S) where the electrode is not formed are narrow or the pressure at the time of crimping in the connection between the electrodes is high (for example, 100 MPa), the conductivity By using the conductive particles according to the present invention in which the particle diameter of the particles is 1 μm or more and 4 μm or less, the particle diameter of the conductive particles is less than 1 μm or more than 4 μm compared to the case of using conductive particles. The effect of reducing the connection resistance can be obtained more effectively.

  The particle diameter of the conductive particles indicates a number average particle diameter. The average particle diameter of the conductive particles can be obtained by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating an average value.

  From the viewpoint of further improving the connection resistance, the conductive particles preferably include base particles and the conductive portions arranged on the surfaces of the base particles.

  Examples of the substrate particles include resin particles, inorganic particles excluding metal particles, organic-inorganic hybrid particles, and metal particles. The substrate particles are preferably substrate particles excluding metal particles, and more preferably resin particles, inorganic particles excluding metal particles, or organic-inorganic hybrid particles. The base particle may be a core-shell particle having a core and a shell disposed on the outer surface of the core. The core may be an inorganic core, and the shell may be an organic shell.

  The substrate particles are preferably resin particles formed of a resin. When connecting between electrodes using the said electroconductive particle, after arrange | positioning the said electroconductive particle between electrodes, the said electroconductive particle is compressed by crimping | bonding. When the substrate particles are resin particles, the conductive particles are easily deformed during the pressure bonding, and the contact area between the conductive particles and the electrode is increased. For this reason, the conduction | electrical_connection reliability between electrodes becomes high.

  Various organic materials are suitably used as the material for the resin particles. Examples of the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene and polybutadiene; acrylic resins such as polymethyl methacrylate and polymethyl acrylate; polyalkylene terephthalate and polysulfone. , Polycarbonate, polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polysulfone, polyphenylene oxide, Polyacetal, polyimide, polyamideimide, polyetherether Tons, polyethersulfone, and polymers such as obtained by a variety of polymerizable monomer having an ethylenically unsaturated group is polymerized with one or more thereof. In addition, by polymerizing one or more of various polymerizable monomers having an ethylenically unsaturated group, it is possible to design and synthesize resin particles having any compression property suitable for conductive materials. . Further, since the hardness of the base particles can be easily controlled within a suitable range, the material of the resin particles is a polymer obtained by polymerizing one or more polymerizable monomers having a plurality of ethylenically unsaturated groups. It is preferable that

  When the resin particles are obtained by polymerizing a monomer having an ethylenically unsaturated group, the monomer having the ethylenically unsaturated group may be a non-crosslinkable monomer or a crosslinkable monomer. And a polymer.

  Examples of the non-crosslinkable monomer include styrene monomers such as styrene and α-methylstyrene; carboxyl group-containing monomers such as (meth) acrylic acid, maleic acid, and maleic anhydride; (Meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl ( Alkyl (meth) acrylates such as meth) acrylate and isobornyl (meth) acrylate; oxygen such as 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate and glycidyl (meth) acrylate (Meth) acrylates; nitrile-containing monomers such as (meth) acrylonitrile; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether; vinyl acids such as vinyl acetate, vinyl butyrate, vinyl laurate, vinyl stearate Esters; Unsaturated hydrocarbons such as ethylene, propylene, isoprene and butadiene; Halogen-containing monomers such as trifluoromethyl (meth) acrylate, pentafluoroethyl (meth) acrylate, vinyl chloride, vinyl fluoride and chlorostyrene Is mentioned.

  Examples of the crosslinkable monomer include tetramethylolmethane tetra (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and dipenta Erythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri (meth) acrylate, glycerol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) Polyfunctional (meth) acrylates such as acrylate, (poly) tetramethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate; triallyl (iso) cyanure And silane-containing monomers such as triallyl trimellitate, divinylbenzene, diallyl phthalate, diallylacrylamide, diallyl ether, γ- (meth) acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, vinyltrimethoxysilane It is done.

  The resin particles can be obtained by polymerizing the polymerizable monomer having an ethylenically unsaturated group by a known method. Examples of this method include a method of suspension polymerization in the presence of a radical polymerization initiator, and a method of polymerization by swelling a monomer together with a radical polymerization initiator using non-crosslinked seed particles.

  In the case where the substrate particles are inorganic particles or organic-inorganic hybrid particles excluding metal particles, examples of the inorganic material that is a material of the substrate particles include silica and carbon black. The particles formed from the silica are not particularly limited. For example, after forming a crosslinked polymer particle by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups, firing may be performed as necessary. The particle | grains obtained by performing are mentioned. Examples of the organic / inorganic hybrid particles include organic / inorganic hybrid particles formed of a crosslinked alkoxysilyl polymer and an acrylic resin.

  When the substrate particles are metal particles, examples of the metal that is a material of the metal particles include silver, copper, nickel, silicon, gold, and titanium. However, the substrate particles are preferably not metal particles.

  Since it is easy to optimize the 10% K value, 20% K value, 30% K value and compression recovery rate of the conductive particles, the substrate particles are organic-inorganic hybrid particles or silica particles. It is preferable.

  The thickness of the conductive portion (when there are a plurality of conductive portions, the total thickness of the plurality of conductive portions) is preferably 5 nm or more, more preferably 10 nm or more, still more preferably 20 nm or more, particularly preferably 50 nm or more, preferably Is 1000 nm or less, more preferably 800 nm or less, still more preferably 500 nm or less, particularly preferably 400 nm or less, and most preferably 300 nm or less. When the thickness of the conductive part is equal to or greater than the lower limit, the conductivity of the conductive particles is further improved. When the thickness of the conductive part is not more than the above upper limit, the difference in the coefficient of thermal expansion between the base particle and the conductive part becomes small, and the conductive part becomes difficult to peel from the base particle. The thickness of the conductive part is an average of the thickness of the conductive part in the entire conductive particles.

  Examples of a method for forming the conductive part on the surface of the substrate particle include a method for forming the conductive part by electroless plating and a method for forming the conductive part by electroplating.

  The conductive part preferably contains a metal. The metal that is the material of the conductive part is not particularly limited. Examples of the metal include gold, silver, copper, platinum, palladium, zinc, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, tungsten, germanium and cadmium, and alloys thereof. Is mentioned. Further, tin-doped indium oxide (ITO) may be used as the metal. As for the said metal, only 1 type may be used and 2 or more types may be used together.

  Since it is easy to optimize the 10% K value, 20% K value, 30% K value and compression recovery rate of the conductive particles, the conductive part is preferably nickel or a nickel alloy.

  The conductive particles have a plurality of protrusions on the conductive surface. Since the core substance is embedded in the conductive portion, protrusions can be easily formed on the outer surface of the conductive portion. An oxide film is often formed on the surface of the electrode connected by the conductive particles. When conductive particles having protrusions are used, the oxide film is effectively excluded by the protrusions by placing the conductive particles between the electrodes and pressing them. For this reason, an electrode and electroconductive particle contact more reliably and the connection resistance between electrodes becomes still lower. Furthermore, the protrusion effectively eliminates the binder resin between the conductive particles and the electrode. For this reason, the conduction | electrical_connection reliability between electrodes becomes high.

  As a method for forming protrusions on the surface of the conductive particles, a method of forming a conductive portion by electroless plating after attaching a core substance to the surface of the base particles, and electroless plating on the surface of the base particles Examples include a method of forming a conductive part by, attaching a core substance, and further forming a conductive part by electroless plating. As another method for forming the protrusion, a first conductive part is formed on the surface of the base particle, and then a core substance is disposed on the first conductive part, and then the second conductive part. And a method of adding a core substance in the middle of forming a conductive part on the surface of the base particle.

  As a method of attaching the core substance to the surface of the base particle, for example, a core substance is added to the dispersion of the base particle, and the core substance is applied to the surface of the base particle by, for example, van der Waals force. Examples thereof include a method of accumulating and adhering, and a method of adding a core substance to a container containing base particles and attaching the core substance to the surface of the base particles by a mechanical action such as rotation of the container. Especially, since the quantity of the core substance to adhere is easy to control, the method of making a core substance accumulate and adhere on the surface of the base particle in a dispersion liquid is preferable.

  Examples of the material of the core substance include a conductive substance and a non-conductive substance. Examples of the conductive material include conductive non-metals such as metals, metal oxides, and graphite, and conductive polymers. Examples of the conductive polymer include polyacetylene. Examples of the nonconductive material include silica, alumina, and zirconia. Among them, metal is preferable because conductivity can be increased and connection resistance can be effectively reduced. The core substance is preferably metal particles.

  Examples of the metal include gold, silver, copper, platinum, zinc, iron, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, tungsten, germanium, and cadmium, and tin. -Alloys composed of two or more metals such as lead alloy, tin-copper alloy, tin-silver alloy, tin-lead-silver alloy, and tungsten carbide. Of these, nickel, copper, silver or gold is preferable. The metal that is the material of the core substance may be the same as or different from the metal that is the material of the conductive part. The material of the core substance preferably includes nickel. Examples of the metal oxide include alumina, silica and zirconia.

  Specific examples of the core material include barium titanate (Mohs hardness 4.5), nickel (Mohs hardness 5), silica (silicon dioxide, Mohs hardness 6-7), titanium oxide (Mohs hardness 7), zirconia. (Mohs hardness 8-9), alumina (Mohs hardness 9), tungsten carbide (Mohs hardness 9), diamond (Mohs hardness 10), and the like. The inorganic particles are preferably nickel, silica, titanium oxide, zirconia, alumina, tungsten carbide or diamond, more preferably silica, titanium oxide, zirconia, alumina, tungsten carbide or diamond, titanium oxide, zirconia. Alumina, tungsten carbide or diamond is more preferable, and zirconia, alumina, tungsten carbide or diamond is particularly preferable. The Mohs hardness of the core material is preferably 5 or more, more preferably 6 or more, still more preferably 7 or more, and particularly preferably 7.5 or more.

  From the viewpoint of effectively reducing the connection resistance between the electrodes, the Mohs hardness of the material of the core substance is preferably equal to or greater than the Mohs hardness of the material of the conductive part, and the Mohs hardness of the material of the conductive part Is preferably larger. The absolute value of the difference between the Mohs hardness of the material of the core substance and the Mohs hardness of the material of the conductive part is preferably 0.1 or more, more preferably 0.2 or more, still more preferably 0.5 or more, particularly preferably Is 1 or more, most preferably 2 or more. In addition, when the conductive portion is formed of a plurality of layers, the material of the core substance is harder than all the metals constituting the plurality of layers, so that the effect of reducing the connection resistance is further increased. Effectively demonstrated.

  The material of the core substance and the material of the conductive part may be the same, but are preferably different. The material of the core substance is a main material (50% by weight or more) constituting the core substance, and is the material most contained in the core substance. The material of the conductive part is a main material (50% by weight or more) constituting the conductive part, and is the material most contained in the conductive part.

  The shape of the core material is not particularly limited. The shape of the core substance is preferably a lump. Examples of the core substance include a particulate lump, an agglomerate in which a plurality of fine particles are aggregated, and an irregular lump.

  The diameter (particle diameter) of the core substance is preferably 0.001 μm or more, more preferably 0.05 μm or more, preferably 0.9 μm or less, more preferably 0.2 μm or less. When the diameter of the core substance is not less than the above lower limit and not more than the above upper limit, the connection resistance between the electrodes is effectively reduced.

  The diameter (particle diameter) of the core substance indicates a number average diameter (number average particle diameter). The diameter of the core material is obtained by observing 50 arbitrary core materials with an electron microscope or an optical microscope and calculating an average value.

  The height of the protrusion in the conductive particle is preferably 0.001 μm or more, more preferably 0.05 μm or more, preferably 0.9 μm or less, more preferably 0.2 μm or less. When the height of the protrusion is not less than the lower limit and not more than the upper limit, the connection resistance between the electrodes is effectively reduced. The height of the protrusion is an average of the heights of a plurality of protrusions per conductive particle. The height of the protrusion is a virtual line of the conductive layer (dashed line shown in FIG. 1) on the assumption that there is no protrusion on the line connecting the center of the conductive particles and the tip of the protrusion (broken line L1 shown in FIG. 1). L2) Indicates the distance from the top (on the outer surface of the spherical conductive particles assuming no projection) to the tip of the projection. That is, in FIG. 1, the distance from the intersection of the broken line L1 and the broken line L2 to the tip of the protrusion is shown.

  From the viewpoint of effectively reducing the connection resistance and effectively increasing the connection reliability between the electrodes, the height of the protrusion is preferably 1/100 or more of the particle diameter of the conductive particles. / 15 or more is more preferable. The height of the protrusion is preferably 1/10 or less of the particle diameter of the conductive particles.

  The number of the protrusions per conductive particle is preferably 3 or more, more preferably 5 or more. The upper limit of the number of protrusions is not particularly limited. The upper limit of the number of protrusions can be appropriately selected in consideration of the particle diameter of the conductive particles.

  The electroconductive particle which concerns on this invention may be equipped with the insulating substance arrange | positioned on the surface (on the outer surface of an electroconductive layer) of the said electroconductive part. In this case, when the conductive particles are used for connection between the electrodes, a short circuit between adjacent electrodes can be further prevented. Specifically, when a plurality of conductive particles are in contact with each other, an insulating material is present between the plurality of electrodes, so that it is possible to prevent a short circuit between electrodes adjacent in the lateral direction instead of between the upper and lower electrodes. In addition, the insulating substance between the conductive layer of an electroconductive particle and an electrode can be easily excluded by pressurizing electroconductive particle with two electrodes in the case of the connection between electrodes. Since the conductive particles have a plurality of protrusions on the outer surface of the conductive layer, the insulating substance between the conductive layer of the conductive particles and the electrode can be easily excluded.

  The insulating substance is preferably an insulating particle because the insulating substance can be more easily removed when the electrodes are pressed.

(Conductive material)
The conductive material according to the present invention includes the conductive particles described above and a binder resin. The conductive particles according to the present invention are preferably dispersed in a binder resin and used as a conductive material.

  The binder resin is not particularly limited. As the binder resin, a known insulating resin can be used. Examples of the binder resin include vinyl resins, thermoplastic resins, curable resins, thermoplastic block copolymers, and elastomers. As for the said binder resin, only 1 type may be used and 2 or more types may be used together.

  Examples of the vinyl resin include vinyl acetate resin, acrylic resin, and styrene resin. Examples of the thermoplastic resin include polyolefin resins, ethylene-vinyl acetate copolymers, and polyamide resins. Examples of the curable resin include an epoxy resin, a urethane resin, a polyimide resin, and an unsaturated polyester resin. The curable resin may be a room temperature curable resin, a thermosetting resin, a photocurable resin, or a moisture curable resin. The curable resin may be used in combination with a curing agent. Examples of the thermoplastic block copolymer include a styrene-butadiene-styrene block copolymer, a styrene-isoprene-styrene block copolymer, a hydrogenated product of a styrene-butadiene-styrene block copolymer, and a styrene-isoprene. -Hydrogenated product of a styrene block copolymer. Examples of the elastomer include styrene-butadiene copolymer rubber and acrylonitrile-styrene block copolymer rubber.

In addition to the conductive particles and the binder resin, the anisotropic conductive material includes, for example, a filler, an extender, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, and a heat stabilizer. Further, various additives such as a light stabilizer, an ultraviolet absorber, a lubricant, an antistatic agent and a flame retardant may be contained.

  The conductive material can be used as a conductive paste and a conductive film. When the conductive material according to the present invention is a conductive film, a film that does not include conductive particles may be laminated on a conductive film that includes conductive particles. The conductive paste is preferably an anisotropic conductive paste. The conductive film is preferably an anisotropic conductive film.

  In 100% by weight of the conductive material, the content of the binder resin is preferably 10% by weight or more, more preferably 30% by weight or more, still more preferably 50% by weight or more, particularly preferably 70% by weight or more, preferably 99.% or more. It is 99 weight% or less, More preferably, it is 99.9 weight% or less. When the content of the binder resin is not less than the above lower limit and not more than the above upper limit, the conductive particles are efficiently arranged between the electrodes, and the connection reliability of the connection target member connected by the conductive material is further increased.

  In 100% by weight of the conductive material, the content of the conductive particles is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, preferably 40% by weight or less, more preferably 20% by weight or less, More preferably, it is 10 weight% or less. When the content of the conductive particles is not less than the above lower limit and not more than the above upper limit, the conduction reliability between the electrodes is further enhanced.

(Connection structure)
A connection structure can be obtained by connecting the connection target members using the conductive particles of the present invention or using a conductive material containing the conductive particles and a binder resin.

  The connection structure connects the first connection target member having the first electrode on the surface, the second connection target member having the second electrode on the surface, and the first and second connection target members. The connection part is formed of the conductive particles of the present invention, or is formed of a conductive material containing the conductive particles and a binder resin, and the first and second electrodes Is preferably a connection structure electrically connected by the conductive particles. In the case where conductive particles are used, the connection portion itself is conductive particles. That is, the first and second connection target members are connected by the conductive particles.

  In the connection structure, at least one of the first electrode and the second electrode is a titanium electrode. Both the first electrode and the second electrode are preferably titanium electrodes because the effect of reducing the connection resistance in the present invention can be obtained more remarkably.

  The titanium electrode contains 50% by weight or more of titanium atoms on the outer surface of the electrode. The titanium electrode may contain aluminum atoms or the like on the outer surface of the electrode as long as the amount is small.

  In FIG. 4, the connection structure using the electroconductive particle which concerns on the 1st Embodiment of this invention is typically shown with front sectional drawing.

  4 includes a first connection target member 52, a second connection target member 53, and a connection portion 54 that connects the first and second connection target members 52 and 53. Prepare. The connection part 54 is formed of a conductive material including the conductive particles 1. The connection part 54 includes the conductive particles 1 and the binder resin 54a. In FIG. 4, the conductive particles 1 are schematically shown for convenience of illustration. Instead of the conductive particles 1, other conductive particles such as the conductive particles 1A and 1B may be used.

  The first connection target member 52 has a plurality of first electrodes 52a on the surface (upper surface). The second connection target member 53 has a plurality of second electrodes 53a on the surface (lower surface). At least one of the first and second electrodes 52a and 53a is a titanium electrode. The first electrode 52 a and the second electrode 53 a are electrically connected by one or a plurality of conductive particles 1. Therefore, the first and second connection target members 52 and 53 are electrically connected by the conductive particles 1.

The manufacturing method of the connection structure is not particularly limited. As an example of a method of manufacturing a connection structure, a method of placing the conductive material between a first connection target member and a second connection target member to obtain a laminate, and then heating and pressurizing the laminate Etc. The pressure of the said pressurization is about 9.8 * 10 < ⁴ > -4.9 * 10 < ⁶ > Pa. The temperature of the said heating is about 120-220 degreeC. The pressure of the pressurization for connecting the electrode of the flexible printed board, the electrode arranged on the resin film, and the electrode of the touch panel is about 9.8 × 10 ^{4 to} 1.0 × 10 ⁶ Pa.

  Specific examples of the connection target member include electronic components such as semiconductor chips, capacitors, and diodes, and electronic components such as printed boards, flexible printed boards, glass epoxy boards, and glass boards. The conductive material is preferably a conductive material for circuit connection. The conductive material is preferably a conductive material for electrically connecting a titanium electrode of an electronic component. The conductive paste is a paste-like conductive material, and is preferably applied on the connection target member in a paste-like state.

  Moreover, it is preferable that the said connection object member is a member for organic EL display elements, and it is preferable that it is a board | substrate for organic EL display elements. The connection target member is preferably an organic EL display element. The conductive material is preferably a conductive material for electrically connecting the titanium electrode of the organic EL display element member.

  From the viewpoint of more effectively obtaining the effect of reducing the connection resistance according to the present invention, the width of the line (L) where the electrode is formed and the width of the space (S) where the electrode is not formed are each preferable. Is 10 μm or more, preferably 100 μm or less, more preferably 90 μm or less, and even more preferably 70 μm or less.

  Examples of the electrode other than the titanium electrode that can be provided on the connection target member include metal electrodes such as a gold electrode, a nickel electrode, a tin electrode, an aluminum electrode, a copper electrode, a molybdenum electrode, and a tungsten electrode. When the connection object member is a flexible printed board, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, or a copper electrode. When the connection target member is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode, or a tungsten electrode. In addition, when the said electrode is an aluminum electrode, the electrode formed only with aluminum may be sufficient and the electrode by which the aluminum layer was laminated | stacked on the surface of the metal oxide layer may be sufficient. Examples of the material for the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal element include Sn, Al, and Ga.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The present invention is not limited only to the following examples.

Example 1
(1) Preparation of substrate particles 300 g of a 0.13% by weight ammonia aqueous solution was placed in a 500 mL reaction vessel equipped with a stirrer and a thermometer. Next, 4.1 g of methyltrimethoxysilane, 19.2 g of vinyltrimethoxysilane, and 0.7 g of silicone alkoxy oligomer (“X-41-1053” manufactured by Shin-Etsu Chemical Co., Ltd.) in an aqueous ammonia solution in the reaction vessel. The mixture with was added slowly. After the hydrolysis and condensation reaction proceeded with stirring, 2.4 mL of a 25 wt% aqueous ammonia solution was added, and then the particles were isolated from the aqueous ammonia solution, and the resulting particles were subjected to an oxygen partial pressure of 10 ⁻¹⁷ atm. And calcining at 350 ° C. for 2 hours to obtain organic-inorganic hybrid substrate particles having a particle size of 3 μm.

(2) Core substance adhesion step The resin particles to which palladium was adhered were stirred and dispersed in 300 mL of ion exchange water for 3 minutes to obtain a dispersion. Next, 1 g of metal nickel particle slurry (average particle diameter 150 nm, nickel Mohs hardness 5) was added to the dispersion over 3 minutes to obtain base particles to which the core substance was adhered.

(3) Preparation of conductive particles After dispersing 10 parts by weight of base material particles, to which the core material is attached, in 100 parts by weight of an alkaline solution containing 5% by weight of a palladium catalyst solution, a solution is obtained. The base material particle to which the core substance was adhered was taken out by filtering. Subsequently, the base material particle to which the core substance was attached was added to 100 parts by weight of a 1% by weight dimethylamine borane solution to activate the surface of the base material particle. The substrate particles whose surface was activated were sufficiently washed with water, and then added to 500 parts by weight of distilled water and dispersed to obtain a suspension.

  Further, a nickel plating solution (pH 8.5) containing 0.23 mol / L of nickel sulfate, 0.92 mol / L of dimethylamine borane, 0.5 mol / L of sodium citrate and 0.01 mol / L of sodium tungstate was prepared.

  While stirring the obtained suspension at 60 ° C., the nickel plating solution was gradually added dropwise to the suspension to perform electroless nickel plating. Thereafter, the suspension is filtered to remove the particles, washed with water, and dried to form a nickel-tungsten-boron conductive layer (thickness of about 0.1 μm, nickel Mohs hardness of 5 on the surface of the base particles). ) Were disposed, and conductive particles having a particle diameter of 3.2 μm were obtained. The height of the protrusion of the obtained conductive particle was 150 nm derived from the core substance.

(Example 2)
Conductive particles were obtained in the same manner as in Example 1 except that the firing temperature during the production of the base particles was changed from 350 ° C to 400 ° C.

(Example 3)
Conductive particles were obtained in the same manner as in Example 1 except that the metal nickel particle slurry (average particle diameter 150 nm) was changed to the metal nickel particle slurry (average particle diameter 50 nm) in the core substance adhesion step.

Example 4
Conductive particles were obtained in the same manner as in Example 1 except that the metal nickel particle slurry (average particle size 150 nm) was changed to the metal nickel particle slurry (average particle size 200 nm) in the core substance adhesion step.

(Example 5)
Conductive particles were obtained in the same manner as in Example 1 except that the metal nickel particle slurry (average particle diameter 150 nm) was changed to the metal nickel particle slurry (average particle diameter 350 nm) in the core substance adhesion step.

(Example 6)
Conductive particles were obtained in the same manner as in Example 2 except that the core material was changed to zirconia slurry (average particle diameter 150 nm, zirconia Mohs hardness 8-9).

(Example 7)
Conductive particles were obtained in the same manner as in Example 2 except that the core material was changed to alumina slurry (average particle diameter 150 nm, alumina Mohs hardness 9).

(Example 8)
Conductive particles were obtained in the same manner as in Example 2 except that the core substance was changed to a tungsten carbide slurry (average particle diameter 150 nm, tungsten carbide Mohs hardness 9).

Example 9
Conductive particles were obtained in the same manner as in Example 2 except that the core substance was changed to diamond slurry (average particle diameter 150 nm, diamond Mohs hardness 10).

(Example 10)
Conductive particles were obtained in the same manner as in Example 2 except that the core substance was changed to a titanium oxide slurry (average particle diameter 150 nm, Mohs hardness 7 of titanium oxide).

(Example 11)
Conductive particles were obtained in the same manner as in Example 2 except that the core substance was changed to barium titanate (average particle size 150 nm, Mohs hardness 4.5 of barium titanate).

Example 12
Conductive particles were obtained in the same manner as in Example 2 except that the particle size of the organic / inorganic hybrid substrate particles was changed to 1 μm to obtain conductive particles having a particle size of 1.2 μm.

(Example 13)
Conductive particles were obtained in the same manner as in Example 2 except that the particle size of the organic / inorganic hybrid substrate particles was changed to 3.8 μm to obtain conductive particles having a particle size of 4.0 μm.

(Example 14)
Conductive particles were obtained in the same manner as in Example 2 except that the particle size of the organic / inorganic hybrid substrate particles was changed to 5 μm to obtain conductive particles having a particle size of 5.2 μm.

(Comparative Example 1)
Conductive particles were obtained in the same manner as in Example 1 except that the oxygen partial pressure during the production of the base particles was changed to a nitrogen partial pressure.

(Comparative Example 2)
Conductive particles were obtained in the same manner as in Example 1 except that the firing temperature during the production of the base particles was changed from 350 ° C to 300 ° C.

(Comparative Example 3)
Conductive particles were obtained in the same manner as in Example 1 except that the firing temperature during the production of the base particles was changed from 350 ° C to 250 ° C.

(Evaluation)
(1) Compression modulus (10% K value, 20% K value and 30% K value)
The compression elastic modulus (10% K value, 20% K value, and 30% K value) of the obtained conductive particles was measured by the above-described method using a micro compression tester (“Fischer Scope H-100” manufactured by Fischer). And measured.

(2) Compression recovery rate The compression recovery rate of the obtained electroconductive particle was measured by the method mentioned above using the micro compression tester ("Fischer scope H-100" by Fischer).

(3) Connection resistance Fabrication of connection structure A:
A transparent glass substrate (first connection target member) having a Ti—Al—Ti multilayer electrode pattern having an L / S of 15 μm / 15 μm on the upper surface was prepared. In addition, a semiconductor chip (second connection target member) having a nickel electrode pattern with a L / S of 15 μm / 15 μm on the lower surface was prepared.

  The obtained anisotropic conductive film was temporarily pressure-bonded and attached to the chip mounting portion on the transparent glass substrate using a temporary pressure bonding machine. Next, after laminating the semiconductor chip so that the electrodes face each other, a pressure heating head is placed on the upper surface of the semiconductor chip while adjusting the temperature of the head so that the temperature of the anisotropic conductive film becomes 150 ° C. The bonded structure A was obtained by applying pressure of 3 MPa and thermocompression bonding for 10 seconds to cure the binder resin in the anisotropic conductive film.

Production of connection structure B:
A transparent glass substrate (first connection target member) having a Ti—Al—Ti multilayer electrode pattern with an L / S of 30 μm / 30 μm on the upper surface was prepared. In addition, a semiconductor chip (second connection target member) having a nickel electrode pattern with a L / S of 30 μm / 30 μm on the lower surface was prepared.

  A connection structure B was obtained in the same manner as the connection structure A except that the first and second connection target members having different L / S were used and that the pressure during crimping was changed to 100 MPa. .

Connection resistance measurement:
The connection resistance between the opposing electrodes of the obtained connection structures A and B was measured by a four-terminal method.

[Evaluation criteria for connection resistance]
◯: Connection resistance is 3.0Ω or less ○: Connection resistance exceeds 3.0Ω, 4.0Ω or less △: Connection resistance exceeds 4.0Ω, 5.0Ω or less ×: Connection resistance exceeds 5.0Ω

  The results are shown in Table 1 below.

  In addition, although the evaluation results of the connection resistance of the connection structures B of Examples 2 and 6 to 10 are all “◯◯”, the value of the connection resistance of the connection structure B of Examples 6 to 10 is It was considerably lower than the connection resistance value of the connection structure B of 2.

DESCRIPTION OF SYMBOLS 1,1A, 1B ... Conductive particle 1a, 1Aa, 1Ba ... Protrusion 2 ... Base material particle 3, 3A, 3B ... Conductive part 3a, 3Aa, 3Ba ... Protrusion 3Bx ... 1st conductive part 3By ... 2nd conductive part DESCRIPTION OF SYMBOLS 4 ... Core substance 51 ... Connection structure 52 ... 1st connection object member 52a ... 1st electrode 53 ... 2nd connection object member 53a ... 2nd electrode 54 ... Connection part 54a ... Binder resin

Claims (9)

Conductive particles used for electrical connection of titanium electrodes,
Having at least a conductive part on the surface;
The conductive part has a plurality of protrusions on the surface;
Compressive modulus when compressed by 10% is at 9000 N / mm ² or more and compression modulus when compressed 20% 8000 N / mm ² or more, 7000N compression elastic modulus when compressed 30% / Mm ² or more,
Conductive particles having a compression recovery rate of 60% or more and 90% or less.   The electroconductive particle of Claim 1 provided with a base particle and the said electroconductive part arrange | positioned on the surface of the said base particle.   The conductive particle according to claim 1 or 2, wherein a height of the protrusion is 1/100 or more of a particle diameter of the conductive particle.   The electroconductive particle of any one of Claims 1-3 which has the some core substance which has raised the surface of the said electroconductive part so that the said some protrusion may be formed in the said electroconductive part.   The conductive particles according to claim 4, wherein the Mohs hardness of the material of the core substance is equal to or greater than the Mohs hardness of the material of the conductive part.   6. The conductive particle according to claim 5, wherein a Mohs hardness of a material of the core substance is larger than a Mohs hardness of a material of the conductive part.   The electroconductive particle of any one of Claims 1-6 whose particle diameter is 1 micrometer or more and 4 micrometers or less.   The electroconductive material containing the electroconductive particle of any one of Claims 1-7, and binder resin. A first connection object member having a first electrode on its surface;
A second connection target member having a second electrode on its surface;
A connecting portion connecting the first connection target member and the second connection target member;
The connecting portion is formed of the conductive particles according to any one of claims 1 to 7, or is formed of a conductive material including the conductive particles and a binder resin.
At least one of the first electrode and the second electrode is a titanium electrode;
A connection structure in which the first electrode and the second electrode are electrically connected by the conductive particles.

Images