JP2013004348A - Conductive particle with insulating particles, anisotropic conductive material, and connection structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive particle with insulating particles capable of enhancing the conduction reliability and the insulation reliability when used for connection between electrodes, and to provide an anisotropic conductive material.SOLUTION: A conductive particle with insulating particles 1 has a conductive particle 2 having a conductive layer 12 at least on a surface thereof, and a plurality of insulating particles 3 adhered on the surface of the conductive particle 2. An average particle size of the insulating particle 3 is larger than 1/10 of a particle size of the conductive particle 2 and equal to or smaller than 1/3 of the same. An anisotropic conductive material contains the conductive particle with insulating particles 1 and a binder resin.

Description

  The present invention relates to conductive particles with insulating particles in which a plurality of insulating particles are attached to the surface of the conductive particles, for example, conductive particles with insulating particles that can be used for electrical connection between electrodes. The present invention also relates to an anisotropic conductive material and a connection structure using the conductive particles with insulating particles.

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

  The anisotropic conductive material is used for connection between an IC chip and a flexible printed circuit board, connection between an IC chip and a circuit board having an ITO electrode, and the like. For example, after disposing an anisotropic conductive material between the electrode of the IC chip and the electrode of the circuit board, these electrodes can be electrically connected by conductive particles by heating and pressing.

  As an example of the conductive particles, the following Patent Documents 1 and 2 disclose conductive particles with insulating particles including conductive particles and insulating particles covering the surface of the conductive particles. ing.

  In the conductive particles with insulating particles described in Patent Document 1, the specific gravity of the conductive particles with insulating particles is 97/100 to 99/100 of the specific gravity of the conductive particles. Patent Document 1 describes that the average particle diameter of the insulating particles is preferably 1/40 to 1/10 of the average particle diameter of the conductive particles.

  Patent Document 2 below discloses conductive particles with insulating particles having conductive particles and insulating particles fixed to the surface of the conductive particles and having fixing properties. The insulating particles include hard particles and a polymer resin layer covering the surfaces of the hard particles. In Patent Document 2, a physical / mechanical hybridization method is used as an immobilization method in order to immobilize insulating particles on the surface of conductive particles.

Japanese Patent No. 4386148 Special table 2007-537570 gazette

  When electrically connecting electrodes using conventional conductive particles with insulating particles as described in Patent Documents 1 and 2, a plurality of conductive particles in a plurality of conductive particles with insulating particles The electrodes adjacent to each other in the lateral direction that should not be connected to each other may be electrically connected. That is, the insulation reliability between the electrodes in the connection structure using the conventional conductive particles with insulating particles may be low.

  In particular, as described in Patent Document 2, when a physical / mechanical hybridization method is used to immobilize the insulating particles on the surface of the conductive particles, the insulating particles are made of conductive particles. Easily detached from the surface. Furthermore, when the physical / mechanical hybridization method is used, the polymer resin layer of the insulating particles adheres to a portion other than the portion where the insulating particles are attached on the surface of the conductive particles. There is also a problem that the conductivity is impaired after the connection between the electrodes.

  An object of the present invention is to provide conductive particles with insulating particles that can improve conduction reliability and insulation reliability when used for connection between electrodes, and anisotropic using the conductive particles with insulating particles. Conductive material and connection structure.

  According to a wide aspect of the present invention, it comprises conductive particles having a conductive layer at least on the surface, and a plurality of insulating particles attached to the surface of the conductive particles, and the average particle size of the insulating particles is The conductive particles with insulating particles, which are more than 1/10 of the particle diameter of the conductive particles and 1/3 or less, are provided.

  On the specific situation with the electroconductive particle with an insulating particle which concerns on this invention, the particle diameter of the said electroconductive particle is 1 micrometer or more and 5 micrometers or less.

  In another specific aspect of the conductive particles with insulating particles according to the present invention, the average particle size of the insulating particles exceeds 1/8 of the particle size of the conductive particles.

  In still another specific aspect of the conductive particle with insulating particles according to the present invention, the insulating particle includes an insulating particle body and a layer covering at least a partial region of the surface of the insulating particle body. And have.

  In another specific aspect of the conductive particles with insulating particles according to the present invention, the insulating particles are attached to the surface of the conductive particles by a chemical method.

  The anisotropic conductive material according to the present invention includes the above-described conductive particles with insulating particles and a binder resin. The anisotropic conductive material according to the present invention is preferably a paste-like anisotropic conductive paste.

  A connection structure according to the present invention includes a first connection target member, a second connection target member, and a connection portion that connects the first and second connection target members. The conductive particles with insulating particles are formed by the above-described conductive particles, or the conductive particles with insulating particles and the anisotropic conductive material containing the binder resin.

  In the conductive particles with insulating particles according to the present invention, a plurality of insulating particles are attached to the surface of the conductive particles having at least a conductive layer on the surface, and the average particle diameter of the insulating particles is the above-described conductive particle. Since it exceeds 1/10 and 1/3 or less of the particle diameter of the particles, when used for connection between the electrodes, it is possible to improve conduction reliability and insulation reliability.

FIG. 1 is a cross-sectional view showing conductive particles with insulating particles according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing conductive particles with insulating particles according to the second embodiment of the present invention. FIG. 3 is a cross-sectional view showing conductive particles with insulating particles according to the third embodiment of the present invention. FIG. 4 is a sectional view showing conductive particles with insulating particles according to the fourth embodiment of the present invention. FIG. 5 is a front cross-sectional view schematically showing a connection structure using conductive particles with insulating particles according to the first embodiment of the present invention. FIG. 6 is a cross-sectional view showing a conventional conductive particle with insulating particles using a hybridization method.

  Details of the present invention will be described below.

  The conductive particles with insulating particles according to the present invention include conductive particles having a conductive layer on at least a surface, and a plurality of insulating particles attached to the surface of the conductive particles. In the conductive particles with insulating particles according to the present invention, the average particle diameter of the insulating particles is more than 1/10 and 1/3 or less of the particle diameter of the conductive particles.

  By adopting the above configuration in the conductive particles with insulating particles according to the present invention, it is possible to effectively suppress contact between the plurality of conductive particles in the conductive particles with insulating particles. In particular, when the electrodes are electrically connected using an anisotropic conductive material containing conductive particles with insulating particles and a binder resin, it is possible to effectively suppress contact between the plurality of conductive particles. Moreover, when electrically connecting electrodes using a paste-like anisotropic conductive material, it can suppress more effectively that several electroconductive particle contacts. For this reason, it is difficult to connect between electrodes adjacent in the lateral direction that should not be connected, and it is possible to suppress a short circuit between the adjacent electrodes. On the other hand, the insulating particles in the conductive particles with insulating particles can be effectively excluded from between the electrode and the conductive particles at the time of pressure bonding. For this reason, the conduction | electrical_connection reliability between the upper and lower electrodes which should be connected can fully be improved. Therefore, by using the conductive particles with insulating particles according to the present invention, both the conduction reliability between the upper and lower electrodes to be connected and the insulation reliability between the laterally adjacent electrodes that should not be connected. Can be increased.

  In addition, the smaller the particle diameter of the conductive particles, the better the insulation reliability is improved because the average particle diameter of the insulating particles exceeds 1/10 of the particle diameter of the conductive particles and is 1/3 or less. It gets quite big. In particular, when the particle diameter of the conductive particles is 1 μm or more and 5 μm or less, the average particle diameter of the insulating particles exceeds 1/10 of the particle diameter of the conductive particles, and is 1/3 or less. The insulation reliability between the electrodes is effectively increased. This is because, when the particle size of the conductive particles is small, the curvature becomes large. Therefore, when the distance between the insulating particles is the same, the conductive layer portion jumps out, and in order to ensure insulation, the particles of the insulating particles This is because it is necessary to increase the diameter.

  From the viewpoint of further improving the conduction reliability and insulation reliability between the electrodes, the average particle diameter of the insulating particles is preferably more than 1/8 of the particle diameter of the conductive particles, and is 1 / 7.5 or more. Is more preferably 1 / 3.5 or less, and still more preferably 1/4 or less. The average particle diameter of the insulating particles may exceed 1/5 of the particle diameter of the conductive particles, or may be 1 / 4.5 or more.

  The coverage, which is the area of the portion covered with the insulating particles in the entire surface area of the conductive particles, is preferably 40% or more, more preferably 60% or more. When the coverage is equal to or higher than the lower limit, adjacent conductive particles are more difficult to contact. The coverage is preferably 95% or less, more preferably 90% or less. If the coverage is less than or equal to the above upper limit, the insulating particles can be sufficiently eliminated without applying heat and pressure more than necessary when the electrodes are connected.

  From the viewpoint of suppressing unintentional detachment of the insulating particles from the surface of the conductive particles, the conductivity with insulating particles obtained by adding 3 parts by weight of conductive particles with insulating particles to 100 parts by weight of ethanol. When the particle-containing liquid is subjected to ultrasonic treatment for 5 minutes at 20 ° C. and 38 kHz, the residual ratio of the insulating particles obtained by the following formula (1) is preferably 60% or more, more preferably 70% or more, preferably It is 95% or less, more preferably 90% or less. When the residual ratio of the insulating particles is equal to or more than the lower limit, the insulating particles are hardly detached from the surface of the conductive particles when the conductive particles with the insulating particles are added to the binder resin and kneaded. As a result, when the electrodes are connected using the conductive particles with insulating particles, a short circuit is unlikely to occur between adjacent electrodes that should not be connected. When the residual ratio of the insulating particles is equal to or lower than the above upper limit, it is possible to sufficiently ensure the conductivity between the upper and lower electrodes to be connected.

  Specifically, the “residual ratio of insulating particles” is determined as follows.

  Before the following ultrasonic treatment, 100 conductive particles with insulating particles were observed by observation with a scanning electron microscope (SEM), and the coverage X1 (%) of the conductive particles in the conductive particles with insulating particles was observed. (Also referred to as adhesion rate X1 (%)) is obtained. The said coverage X1 is an area of the part coat | covered with the insulating particle which occupies for the whole surface area of electroconductive particle.

  Next, 3 parts by weight of conductive particles with insulating particles are added to 100 parts by weight of ethanol to obtain a conductive particle-containing liquid with insulating particles. This conductive particle-containing liquid with insulating particles is subjected to ultrasonic treatment while being stirred for 5 minutes at 20 ° C. and 40 kHz with an ultrasonic cleaner. After the ultrasonic treatment, 100 conductive particles with insulating particles are observed by observation with an SEM, and the portion of the conductive particles with insulating particles covered by the insulating particles occupying the entire surface area of the conductive particles. The area coverage ratio X2 (%) (also referred to as adhesion rate X2 (%)) is obtained. The residual rate of the insulating particles is a value represented by the following formula (1) from the coverage X1 and the coverage X2.

  Residual rate of insulating particles (%) = (coverage ratio X2 after ultrasonic treatment / coverage ratio X1 before ultrasonic treatment) × 100 Formula (1)

  In the conductive particles with insulating particles according to the present invention, the insulating particles preferably have an insulating particle body and a layer covering at least a part of the surface of the insulating particle body. Thereby, it becomes more difficult for the insulating particles to be detached from the surface of the conductive particles by kneading during the production of the anisotropic conductive material. Furthermore, when a plurality of conductive particles with insulating particles come into contact, the insulating particles are difficult to be detached from the surface of the conductive particles. In order to effectively suppress unintended detachment of the insulating particles, the material of the insulating particle body is preferably an inorganic compound, and the insulating particle body is preferably inorganic particles. In order to effectively suppress unintentional detachment of the insulating particles, the layer covering at least a part of the surface of the insulating particle main body is preferably formed of an organic compound. The compound is preferably a polymer compound.

  The conductive particles with insulating particles have a layer formed of a polymer compound using a polymer compound or a compound that becomes a polymer compound so as to cover at least a part of the surface of the insulating particle body. It is preferably obtained through a step of forming and obtaining insulating particles and a step of attaching the insulating particles to the surface of the conductive particles having at least the surface of the conductive layer to obtain conductive particles with insulating particles.

  The conductive particles with insulating particles according to the present invention preferably further include a coating covering the surface of the conductive particles. The coating preferably covers the surface of the conductive particles and the surface of the insulating particles. By the coating film, the surface of the conductive layer is not exposed or the exposed area of the surface of the conductive layer is reduced, and rust is hardly generated in the conductive layer. For this reason, high conductivity can be maintained over a long period of time, and conduction reliability between the electrodes can be increased.

  From the viewpoint of making rust more difficult to occur in the conductive layer, the coating is preferably formed of a compound having an alkyl group having 6 to 22 carbon atoms.

  The conductive particles with insulating particles according to the present invention are preferably conductive particles with insulating particles used in a paste-like anisotropic conductive paste.

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

(Conductive particles with insulating particles)
FIG. 1 is a sectional view showing conductive particles with insulating particles according to the first embodiment of the present invention. In addition, in the electroconductive particle with an insulating particle shown in FIG.1 and FIGS.2-4, the magnitude | size of an insulating particle and an electroconductive particle can be suitably changed within the range mentioned above.

  A conductive particle 1 with insulating particles shown in FIG. 1 includes conductive particles 2 and a plurality of insulating particles 3 attached to the surface of the conductive particles 2. Insulating particles 43 described later may be used instead of the insulating particles 3.

  The insulating particles 3 include an insulating particle body 5 and a layer 6 that covers the surface of the insulating particle body 5 and is formed of a polymer compound. The insulating particles 3 are made of an insulating material. The insulating particles 3 are coated particles.

  The layer 6 covers the entire surface of the insulating particle body 5. Therefore, the layer 6 is disposed between the conductive particles 2 and the insulating particle main body 5. The layer 6 may be present so as to cover at least a part of the surface of the insulating particle main body, and may not cover the entire surface of the insulating particle main body. The layer 6 is preferably disposed between the conductive particles and the insulating particle main body.

  The conductive particles 2 include base material particles 11 and a conductive layer 12 disposed on the surface of the base material particles 11. The conductive layer 12 covers the surface of the base particle 11. The conductive particle 2 is a coated particle in which the surface of the base particle 11 is coated with the conductive layer 12. The conductive particles 2 have a conductive layer 12 on the surface.

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

  The conductive particles 21 with insulating particles shown in FIG. 2 include conductive particles 22 and a plurality of insulating particles 3 attached to the surface of the conductive particles 22. Insulating particles 43 described later may be used instead of the insulating particles 3.

  The conductive particles 22 have base material particles 11 and a conductive layer 31 disposed on the surface of the base material particles 11. The conductive particles 22 have a plurality of core substances 32 on the surface of the substrate particles 11. The conductive layer 31 covers the base particle 11 and the core substance 32. By covering the core substance 32 with the conductive layer 31, the conductive particles 22 have a plurality of protrusions 33 on the surface. The surface of the conductive layer 31 is raised by the core substance 32, and a plurality of protrusions 33 are formed.

  In FIG. 3, the electroconductive particle with an insulating particle which concerns on the 3rd Embodiment of this invention is shown with sectional drawing.

  A conductive particle 41 with insulating particles shown in FIG. 3 includes conductive particles 42 and a plurality of insulating particles 43 attached to the surface of the conductive particles 42. The insulating particles 3 may be used instead of the insulating particles 43.

  The conductive particles 42 include base material particles 11 and a conductive layer 51 disposed on the surface of the base material particles 11. The conductive particles 42 do not have a core substance like the conductive particles 22. The conductive layer 51 has a first portion and a second portion that is thicker than the first portion. The conductive particles 42 have a plurality of protrusions 52 on the surface. A portion excluding the plurality of protrusions 52 is the first portion of the conductive layer 51. The plurality of protrusions 52 are the second portion where the conductive layer 51 is thick.

  The insulating particles 43 are not coated particles.

  FIG. 4 is a sectional view showing conductive particles with insulating particles according to the fourth embodiment of the present invention.

  The conductive particles 61 with insulating particles shown in FIG. 4 include conductive particles 2, a plurality of insulating particles 43 attached to the surface of the conductive particles 2, and the conductive particles 2 and the insulating particles 43. And a coating 62 covering the surface. The conductive particles 22 and 42 may be used instead of the conductive particles 2. The insulating particles 3 may be used instead of the insulating particles 43.

  The coating 62 does not necessarily have to cover the entire surfaces of the conductive particles 2 and the insulating particles 43. By covering at least a part of the surface of the conductive layer 12 with the coating 62, the rust of the conductive layer 12 can be suppressed in the portion where the coating 62 is formed.

  From the viewpoint of making the conductive layer 12 more difficult to cause rust, the treatment liquid containing the peeled coating 62 is obtained by treating the conductive particles 61 with insulating particles with a 5 wt% aqueous citric acid solution and peeling the coating 62. It is preferable that the filtrate obtained by filtering the treatment liquid after obtaining the above contains 50 ppm or more and 10,000 ppm or less of the phosphorus element. From the viewpoint of making the conductive layer 12 more difficult to cause rust, the treatment liquid containing the peeled coating 62 is obtained by treating the conductive particles 61 with insulating particles with a 5 wt% aqueous citric acid solution and peeling the coating 62. It is preferable that the filtrate obtained by filtering the treatment liquid after obtaining the above contains 50 ppm or more and 10,000 ppm or less of silicon element. The content of silicon element or phosphorus element in the filtrate is more preferably 100 ppm or more, more preferably 5000 ppm or less, and still more preferably 1000 ppm or less.

  The contents of the phosphorus element and silicon element can be measured using an ICP emission analyzer. Examples of commercially available ICP emission analyzers include “ULTIMA2” manufactured by HORIBA, Ltd.

  In the case of the conductive particles 61 with insulating particles having the coating 62, the contents of the phosphorus element and the silicon element are usually determined by the coating 62. That is, the contents of the phosphorus element and the silicon element indicate the ratio of the phosphorus element and the silicon element in the coating 62.

  In the conductive particles 1, 21, 41, 61 with insulating particles, the average particle diameter of the insulating particles 3, 43 exceeds 1/10 of the particle diameter of the conductive particles 2, 22, 42, and is 1/3 or less. It is. By electrically connecting the electrodes using such conductive particles with insulating particles 1, 21, 41, 61, the connection resistance between the upper and lower electrodes can be effectively reduced. Can be more reliably conducted. Furthermore, it is difficult for a short circuit to occur between adjacent electrodes that should not be connected.

  Hereinafter, details of the conductive particles, the insulating particles, and the coating will be described.

[Conductive particles]
Conductive particles with insulating particles can be obtained by attaching the insulating particles to the surface of conductive particles having at least a conductive layer on the surface.

  The conductive particles only need to have a conductive layer on at least the surface. The conductive particles may be conductive particles having base particles and a conductive layer disposed on the surface of the base particles. The conductive particles may be metal particles whose entirety is a conductive layer. Among these, from the viewpoint of reducing the cost, increasing the flexibility of the conductive particles, and improving the conduction reliability between the electrodes, the base particles were provided on the surface of the base particles. Conductive particles having a conductive layer are preferred.

  Examples of the substrate particles include resin particles, inorganic particles, organic-inorganic hybrid particles, and metal particles.

  The substrate particles are preferably resin particles formed of a resin. When connecting the electrodes using the conductive particles with insulating particles, the conductive particles with insulating particles are compressed by placing the conductive particles with insulating particles between the electrodes and then pressing them. When the substrate particles are resin particles, the conductive particles are likely to be 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.

  Examples of the resin for forming the resin particles include polyolefin resin, acrylic resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polysulfone, and polyphenylene. Examples thereof include oxides, polyacetals, polyimides, polyamideimides, polyetheretherketones, and polyethersulfones. Since the hardness of the base particles can be easily controlled within a suitable range, the resin for forming the resin particles is a polymer obtained by polymerizing one or more polymerizable monomers having an ethylenically unsaturated group. It is preferably a coalescence.

  Examples of the inorganic substance for forming the inorganic particles include silica and carbon black. 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 for forming the metal particles include silver, copper, nickel, silicon, gold, and titanium.

  The metal for forming the conductive layer is not particularly limited. Furthermore, when the conductive particles are metal particles that are conductive layers as a whole, the metal for forming the metal particles is not particularly limited. Examples of the metal include gold, silver, copper, palladium, platinum, palladium, zinc, iron, tin, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, thallium, germanium, cadmium, and silicon. And alloys thereof. Examples of the metal include tin-doped indium oxide (ITO) and solder. Especially, since the connection resistance between electrodes becomes still lower, an alloy containing tin, nickel, palladium, copper or gold is preferable, and nickel or palladium is more preferable.

  Note that hydroxyl groups often exist on the surface of the conductive layer due to oxidation. In general, hydroxyl groups are present on the surface of a conductive layer formed of nickel by oxidation. Such a conductive layer having a hydroxyl group is easily chemically bonded to the insulating particles, for example, chemically bonded to the insulating particles having a hydroxyl group.

  The conductive layer is formed of one layer. The conductive layer may be formed of a plurality of layers. That is, the conductive layer may have a stacked structure of two or more layers. When the conductive layer is formed of a plurality of layers, the outermost layer is preferably a gold layer, a nickel layer, a palladium layer, a copper layer, or an alloy layer containing tin and silver, and the gold layer or the palladium layer Is more preferable, and a gold layer is particularly preferable. When the outermost layer is these preferred conductive layers, the connection resistance between the electrodes is further reduced. Moreover, when the outermost layer is a gold layer, the corrosion resistance is further enhanced.

  The method for forming the conductive layer on the surface of the substrate particles is not particularly limited. As a method for forming the conductive layer, for example, a method by electroless plating, a method by electroplating, a method by physical vapor deposition, and a method of coating the surface of base particles with metal powder or a paste containing metal powder and a binder Etc. Especially, since formation of a conductive layer is simple, the method by electroless plating is preferable. Examples of the method by physical vapor deposition include methods such as vacuum vapor deposition, ion plating, and ion sputtering.

  As a method for forming a conductive layer on the surface of the substrate particles, a method by physical collision is also effective from the viewpoint of improving productivity. As a method of forming by physical collision, for example, there is a method of coating using a theta composer (manufactured by Tokuju Kogakusha Co., Ltd.).

  The particle diameter and average particle diameter of the conductive particles are each preferably 0.5 μm or more, more preferably 1 μm or more, preferably 100 μm or less, more preferably 20 μm or less, and even more preferably 5 μm or less. When the average particle diameter of the conductive particles is not less than the above lower limit and not more than the upper limit, the contact area between the conductive particles and the electrodes becomes sufficiently large when the electrodes are connected using the conductive particles with insulating particles. And it becomes difficult to form the agglomerated conductive particles when the conductive layer is formed. 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 “average particle size” of the conductive particles indicates a number average particle size. 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.

  The thickness of the conductive layer is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 1 μm or less, more preferably 0.3 μm or less. When the thickness of the conductive layer is not less than the above lower limit and not more than the above upper limit, sufficient conductivity is obtained, and the conductive particles do not become too hard, and the conductive particles are sufficiently deformed when connecting the electrodes. .

  When the conductive layer is formed of a plurality of layers, the thickness of the outermost conductive layer is preferably 0.001 μm or more, more preferably the thickness of the gold layer when the outermost layer is a gold layer. It is 0.01 μm or more, preferably 0.5 μm or less, more preferably 0.1 μm or less. When the thickness of the outermost conductive layer is not less than the lower limit and not more than the upper limit, the outermost conductive layer can be uniformly coated, the corrosion resistance is sufficiently high, and the connection resistance between the electrodes is sufficiently high. Lower.

  The thickness of the conductive layer can be measured, for example, by observing the cross section of the conductive particles or the conductive particles with insulating particles using a transmission electron microscope (TEM).

  The conductive particles preferably have protrusions on the surface. The conductive particles preferably have a plurality of protrusions on the surface of the conductive layer. An oxide film is often formed on the surface of the electrode connected by the conductive particles with insulating particles. Furthermore, an oxide film is often formed on the surface of the conductive layer of the conductive particles. By using the conductive particles having protrusions, the oxide film is effectively excluded by the protrusions by placing the conductive particles with insulating particles between the electrodes and then pressing them. For this reason, an electrode and electroconductive particle contact still more reliably and the connection resistance between electrodes becomes low. Furthermore, the insulating particles between the conductive particles and the electrode can be effectively excluded by the protrusions of the conductive particles. For this reason, the conduction | electrical_connection reliability between electrodes becomes high.

  As a method of forming protrusions on the surface of the conductive particles, a method of forming a conductive layer by electroless plating after attaching a core substance to the surface of the base particles, and by electroless plating on the surface of the base particles Examples of the method include forming a conductive layer, then attaching a core substance, and further forming a conductive layer by electroless plating. Further, when the conductive layer is formed by electroless plating or the like, the protrusion can also be formed by partially varying the thickness of the conductive layer.

  As a method for attaching the core substance to the surface of the base particle, for example, a conductive substance that becomes the core substance is added to the dispersion of the base particle, and the core substance is added to the surface of the base particle, for example, A method of accumulating and adhering by van der Waals force, and adding a conductive substance as a core substance to the container containing the base particle, and then the core on the surface of the base particle by mechanical action such as rotation of the container Examples include a method of attaching a substance. 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 conductive material constituting the core material include conductive non-metals such as metals, metal oxides, and graphite, and conductive polymers. Examples of the conductive polymer include polyacetylene. Among them, metal is preferable because conductivity can be increased.

  Examples of the metal include gold, silver, copper, platinum, zinc, iron, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium, and cadmium, and tin-lead. Examples include alloys composed of two or more metals such as alloys, tin-copper alloys, tin-silver alloys, and tin-lead-silver alloys. Of these, nickel, copper, silver or gold is preferable. The metal constituting the core material may be the same as or different from the metal constituting the conductive layer.

  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.

[Insulating particles]
The insulating particles are particles having insulating properties. Insulating particles are smaller than conductive particles. When the electrodes are connected using conductive particles with insulating particles, the insulating particles can prevent a short circuit between adjacent electrodes. Specifically, when the conductive particles with a plurality of insulating particles are in contact with each other, there are insulating particles between the conductive particles in the conductive particles with a plurality of insulating particles. Short circuit between the electrodes adjacent in the lateral direction can be prevented. Note that the insulating particles between the conductive layer and the electrode can be easily excluded by pressurizing the conductive particles with insulating particles with the two electrodes when connecting the electrodes. Since the protrusion is provided on the surface of the conductive particle, the insulating particle between the conductive layer and the electrode can be easily excluded. Furthermore, since the protruding portion facilitates contact with the electrode, connection reliability is improved.

  Examples of the material constituting the insulating particles include an insulating resin and an insulating inorganic substance. As said insulating resin, the said resin quoted as resin for forming the resin particle which can be used as a base particle is mentioned. As said insulating inorganic substance, the said inorganic substance quoted as an inorganic substance for forming the inorganic particle which can be used as a base particle is mentioned.

  Specific examples of the insulating resin that is the material of the insulating particles include polyolefins, (meth) acrylate polymers, (meth) acrylate copolymers, block polymers, thermoplastic resins, crosslinked thermoplastic resins, heat Examples thereof include curable resins and water-soluble resins.

  Examples of the polyolefins include polyethylene, ethylene-vinyl acetate copolymer, and ethylene-acrylic acid ester copolymer. Examples of the (meth) acrylate polymer include polymethyl (meth) acrylate, polyethyl (meth) acrylate, and polybutyl (meth) acrylate. Examples of the block polymer include polystyrene, styrene-acrylic acid ester copolymer, SB type styrene-butadiene block copolymer, SBS type styrene-butadiene block copolymer, and hydrogenated products thereof. Examples of the thermoplastic resin include vinyl polymers and vinyl copolymers. As said thermosetting resin, an epoxy resin, a phenol resin, a melamine resin, etc. are mentioned. Examples of the water-soluble resin include polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinyl pyrrolidone, polyethylene oxide, and methyl cellulose. Of these, water-soluble resins are preferable, and polyvinyl alcohol is more preferable.

  From the viewpoint of further improving the detachability of the insulating particles during thermocompression bonding, the insulating particles or the insulating particle main body is preferably inorganic particles, and is preferably silica particles. Inorganic particles are relatively hard, especially silica particles are relatively hard. When conductive particles with insulating particles using such hard insulating particles as insulating particles are added to a binder resin and kneaded, the insulating particles are hard, so that the insulating particles are removed from the surface of the conductive particles. There is a tendency to detach easily. In the case where the insulating particles have a layer formed of the polymer compound, even if hard insulating particles are used, it is possible to suppress the separation of the hard insulating particles during the kneading.

  The layer formed of the organic compound and the layer formed of the polymer compound serve as a flexible layer, for example. The polymer compound in the layer formed of the polymer compound or the compound that becomes the polymer compound by polymerization or the like is preferably a compound having a polymerizable reactive functional group. The polymerizable reactive functional group is preferably an unsaturated double bond. Examples of the polymer compound include a compound having a (meth) acryloyl group, a compound having an epoxy group, and a compound having a vinyl group. From the viewpoint of suppressing detachment of the insulating particles from the surface of the conductive particles when dispersing the conductive particles with insulating particles, the polymer compound or the compound to be the polymer compound is (meth) It preferably has at least one reactive functional group selected from the group consisting of an acryloyl group, a glycidyl group and a vinyl group. Among these, from the viewpoint of further suppressing the detachment of the insulating particles, the polymer compound or the compound to be the polymer compound preferably has a (meth) acryloyl group.

  Specific examples of the compound having the (meth) acryloyl group include methacrylic acid and hydroxyethyl acrylate.

  Specific examples of the epoxy compound include bisphenol A type epoxy resin and resorcinol glycidyl ether.

  Specific examples of the compound having a vinyl group include styrene and vinyl acetate.

  The polymer compound preferably has a weight average molecular weight of 1000 or more. The weight average molecular weight indicates a value in terms of polystyrene measured by gel permeation chromatography (GPC).

  A method for forming the layer formed of the polymer compound on the surface of the insulating particle body is not particularly limited. Using a polymer compound or a compound that becomes a polymer compound so as to cover at least a part of the surface of the insulating particle main body, a layer formed of the polymer compound is formed to obtain insulating particles. preferable. As an example of a method for forming a layer formed of the polymer compound, a compound having a reactive double bond and a hydroxyl group is formed on an insulating particle body having a reactive functional group such as a vinyl group on the surface. And a method of polymerizing on the surface. However, methods other than this forming method may be used.

  The following manufacturing conditions are mentioned as an example of the specific manufacturing conditions of the layer formed with the said high molecular compound.

  First, in 100 to 500 parts by weight of a solvent such as water, 1 to 3 parts by weight of an insulating particle body having a reactive functional group on the surface, and 0.1 to 1 part by weight of a compound having a reactive double bond and a hydroxyl group , 0.01 to 1 part by weight of a crosslinking agent, 0.1 to 3 parts by weight of a dispersant and 0.1 to 3 parts by weight of a thermal polymerization initiator are added. Next, while stirring with a three-one motor, the temperature is raised to a temperature higher than the reaction temperature of the thermal polymerization initiator in an oil bath, polymerization is started, and the state is maintained for 5 hours or longer to react. Thereafter, unreacted compounds are removed using a centrifuge to obtain insulating particles in which the surface of the insulating particle main body is covered with the layer.

  When there are hydroxyl groups on the surface of the insulating particles and the surface of the conductive particles, the adhesion between the insulating particles and the conductive particles is moderately increased by the dehydration reaction.

  Examples of the compound having a hydroxyl group for introducing a hydroxyl group include a P—OH group-containing compound and a Si—OH group-containing compound.

  Specific examples of the P-OH group-containing compound include acid phosphooxyethyl methacrylate, acid phosphooxypropyl methacrylate, acid phosphooxypolyoxyethylene glycol monomethacrylate, and acid phosphooxypolyoxypropylene glycol monomethacrylate. As for the said P-OH group containing compound, only 1 type may be used and 2 or more types may be used together.

  Specific examples of the Si-OH group-containing compound include vinyltrihydroxysilane and 3-methacryloxypropyltrihydroxysilane. As for the said Si-OH group containing compound, only 1 type may be used and 2 or more types may be used together.

  For example, insulating particles having a hydroxyl group on the surface can be obtained by a treatment using a silane coupling agent. Examples of the silane coupling agent include hydroxytrimethoxysilane.

  The average particle diameter of the insulating particles can be appropriately selected in consideration of the particle diameter of the conductive particles. The average particle size of the insulating particles is preferably 0.01 μm or more, preferably 5 μm or less, more preferably 2.5 μm or less, still more preferably 1 μm or less, and particularly preferably 0.5 μm or less. When the average particle diameter of the insulating particles is not less than the above lower limit, the conductive particles in the plurality of conductive particles with insulating particles are difficult to contact when the conductive particles with insulating particles are dispersed in the binder resin. Become. When the average particle diameter of the insulating particles is not more than the above upper limit, it is not necessary to make the pressure too high in order to eliminate the insulating particles between the electrodes and the conductive particles when connecting the electrodes, There is no need to heat to high temperatures.

  In addition, the average particle diameter of the said insulating particle shows the number average particle diameter of the insulating particle adhering to electroconductive particle. The average particle size of the insulating particles is determined using a particle size distribution measuring device or the like.

[Coating]
The coating is preferably formed of a compound having an alkyl group having 6 to 22 carbon atoms (hereinafter also referred to as compound A). When the number of carbon atoms of the alkyl group is 6 or more, rust is further hardly generated on the surface of the conductive layer. When the carbon number of the alkyl group is 22 or less, the conductivity of the conductive particles with insulating particles is increased. From the viewpoint of further increasing the conductivity of the conductive particles with insulating particles, the alkyl group in the compound A preferably has 16 or less carbon atoms. The alkyl group may have a linear structure or a branched structure. The alkyl group preferably has a linear structure.

  The compound A is not particularly limited as long as it has an alkyl group having 6 to 22 carbon atoms. The compound A has a phosphate ester having an alkyl group having 6 to 22 carbon atoms or a salt thereof, a phosphite ester having an alkyl group having 6 to 22 carbon atoms or a salt thereof, and an alkyl group having 6 to 22 carbon atoms. It is preferably at least one selected from the group consisting of alkoxysilanes, alkylthiols having an alkyl group having 6 to 22 carbon atoms, and dialkyl disulfides having an alkyl group having 6 to 22 carbon atoms. By using these preferable compounds A, it is possible to further prevent rust from being generated in the conductive layer. From the viewpoint of making rust less likely to occur, the compound A is preferably at least one selected from the group consisting of the phosphate ester or a salt thereof, a phosphite ester or a salt thereof and an alkoxysilane, More preferably, the phosphoric acid ester or a salt thereof and a phosphorous acid ester or a salt thereof are at least one of them. As for the said compound A, only 1 type may be used and 2 or more types may be used together.

  The compound A preferably has a reactive functional group capable of reacting with the conductive particles. The compound A preferably has a reactive functional group capable of reacting with insulating particles. It is preferable that the coating is chemically bonded to the conductive particle portion with insulating particles (conductive particles or insulating particles) excluding the coating. The coating is preferably chemically bonded to the conductive particles. The coating is preferably chemically bonded to the insulating particles. More preferably, the coating is chemically bonded to the conductive particles and the insulating particles. Due to the presence of the reactive functional group and the chemical bond, peeling of the film is less likely to occur, and as a result, rust is less likely to occur in the conductive layer, and insulating particles are not intended from the surface of the conductive particles. Makes it more difficult to detach.

  Examples of the phosphoric acid ester having an alkyl group having 6 to 22 carbon atoms or a salt thereof include, for example, phosphoric acid hexyl ester, phosphoric acid heptyl ester, phosphoric acid monooctyl ester, phosphoric acid monononyl ester, phosphoric acid monodecyl ester, Monoundecyl phosphate, monododecyl phosphate, monotridecyl phosphate, monotetradecyl phosphate, monopentadecyl phosphate, monohexyl phosphate monosodium salt, monoheptyl phosphate monosodium Salts, monooctyl phosphate monosodium salt, monononyl phosphate monosodium salt, monodecyl phosphate monosodium salt, monoundecyl phosphate monosodium salt, monododecyl phosphate monosodium salt, Phosphate mono tridecyl ester monosodium salt, phosphate acid mono tetradecyl ester monosodium salt and phosphoric acid mono pentadecyl ester monosodium salt. You may use the potassium salt of the said phosphate ester.

  Examples of the phosphite ester having an alkyl group having 6 to 22 carbon atoms or a salt thereof include, for example, hexyl phosphite ester, heptyl phosphite ester, monooctyl phosphite ester, monononyl phosphite ester, Phosphoric acid monodecyl ester, phosphorous acid monoundecyl ester, phosphorous acid monododecyl ester, phosphorous acid monotridecyl ester, phosphorous acid monotetradecyl ester, phosphorous acid monopentadecyl ester, phosphorous acid monohexyl Ester monosodium salt, phosphorous acid monoheptyl ester monosodium salt, phosphorous acid monooctyl ester monosodium salt, phosphorous acid monononyl ester monosodium salt, phosphorous acid monodecyl ester monosodium salt, phosphorous acid monoun Decyl ester monosodium salt, phosphorous acid Dodecyl ester monosodium salt, phosphorous acid mono-tridecyl ester monosodium salt, phosphorous acid mono-tetradecyl ester monosodium salt and phosphorous acid mono-pentadecyl ester monosodium salt. You may use the potassium salt of the said phosphite.

  Examples of the alkoxysilane having an alkyl group having 6 to 22 carbon atoms include hexyltrimethoxysilane, hexyltriethoxysilane, heptyltrimethoxysilane, heptyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, and nonyltri. Methoxysilane, nonyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, undecyltrimethoxysilane, undecyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, tridecyltrimethoxysilane, tridecyltriethoxy Examples include silane, tetradecyltrimethoxysilane, tetradecyltriethoxysilane, pentadecyltrimethoxysilane, and pentadecyltriethoxysilane.

  Examples of the alkyl thiol having an alkyl group having 6 to 22 carbon atoms include hexyl thiol, heptyl thiol, octyl thiol, nonyl thiol, decyl thiol, undecyl thiol, dodecyl thiol, tridecyl thiol, tetradecyl thiol, pentadecyl. Examples include thiol and hexadecyl thiol. The alkyl thiol preferably has a thiol group at the end of the alkyl chain.

  Examples of the dialkyl disulfide having an alkyl group having 6 to 22 carbon atoms include dihexyl disulfide, diheptyl disulfide, dioctyl disulfide, dinonyl disulfide, didecyl disulfide, diundecyl disulfide, didodecyl disulfide, ditridecyl disulfide, ditetradecyl disulfide. Examples include decyl disulfide, dipentadecyl disulfide, and dihexadecyl disulfide.

(Other details of conductive particles with insulating particles)
Examples of the method for attaching the insulating particles to the surface of the conductive particles and the surface of the conductive layer include a chemical method and a physical or mechanical method. Examples of the chemical method include an interfacial polymerization method, a suspension polymerization method in the presence of particles, and an emulsion polymerization method. Examples of the physical or mechanical method include spray drying, hybridization, electrostatic adhesion, spraying, dipping, and vacuum deposition. However, the hybridization method tends to cause desorption of insulating particles. For this reason, the method of attaching insulating particles to the surfaces of the conductive particles and the conductive layer is preferably a method other than the hybridization method. In particular, a method in which insulating particles are attached to the surface of the conductive particles and the surface of the conductive layer through a chemical bond is preferable because the insulating particles are not easily detached. That is, a chemical method is preferable, and the insulating particles are preferably attached to the surface of the conductive particles by a chemical method.

  In the conductive particles with insulating particles according to the present invention, the insulating particles are preferably not attached by a hybridization method. It is preferable that the polymer compound is not attached to a portion other than the portion to which the insulating particles are attached on the surface of the conductive particles. Such conductive particles with insulating particles can be obtained without using a hybridization method.

  As shown in FIG. 6, in the conventional conductive particles 101 with insulating particles using the hybridization method, the portions 102 b other than the portions 102 a on the surface of the conductive particles 102 are attached to the portions 102 b. Also, the polymer compound 104 adheres. This is because in the hybridization method, a compressive shear force is applied, the insulating particles are repeatedly attached and detached, and the insulating particles are gradually attached. The layer formed of the polymer compound of the insulating particles is peeled off by the compressive shearing force, and the peeled polymer compound is attached to a portion other than the portion where the insulating particles are attached on the surface of the conductive particles. The polymer compound adhering to the portion other than the portion to which the insulating particles adhere on the surface of the conductive particles increases the volume resistivity of the conductive particles or decreases the connection resistance between the electrodes.

  As an example of the method of attaching insulating particles to the surface of the conductive particles and the surface of the conductive layer, the following methods may be mentioned.

  First, the conductive particles are put in a solvent such as water, and the insulating particles are gradually added while stirring. After sufficiently stirring, the conductive particles with insulating particles are separated and dried by a vacuum dryer or the like to obtain conductive particles with insulating particles.

  The conductive layer preferably has a reactive functional group capable of reacting with insulating particles on the surface. The insulating particles preferably have a reactive functional group capable of reacting with the conductive layer on the surface. These reactive functional groups make it difficult for the insulating particles to be unintentionally detached from the surface of the conductive particles.

  As the reactive functional group, an appropriate group is selected in consideration of reactivity. Examples of the reactive functional group include a hydroxyl group, a vinyl group, and an amino group. Since the reactivity is excellent, the reactive functional group is preferably a hydroxyl group. The conductive particles preferably have a hydroxyl group on the surface. The insulating particles preferably have a hydroxyl group on the surface.

(Anisotropic conductive material)
The anisotropic conductive material according to the present invention includes the above-described conductive particles with insulating particles and a binder resin.

  The binder resin is not particularly limited. In general, an insulating resin is used as the binder resin. 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 with insulating 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, and an antioxidant. In addition, various additives such as a heat stabilizer, a light stabilizer, an ultraviolet absorber, a lubricant, an antistatic agent and a flame retardant may be contained.

  The method for dispersing the conductive particles with insulating particles in the binder resin is not particularly limited, and a conventionally known dispersion method can be used. As a method for dispersing the conductive particles with insulating particles in the binder resin, for example, the conductive particles with insulating particles are added to the binder resin and then kneaded and dispersed with a planetary mixer or the like. A method, a method in which the conductive particles with insulating particles are uniformly dispersed in water or an organic solvent using a homogenizer or the like, then added to the binder resin, and kneaded and dispersed with a planetary mixer or the like; and Examples include a method of diluting the binder resin with water or an organic solvent, adding the conductive particles with insulating particles, and kneading and dispersing with a planetary mixer or the like.

  The anisotropic conductive material according to the present invention can be used as an anisotropic conductive paste and an anisotropic conductive film. The anisotropic conductive paste may be an anisotropic conductive ink or an anisotropic conductive adhesive. The anisotropic conductive film includes an anisotropic conductive sheet. When the anisotropic conductive material containing the conductive particles of the present invention is used as a film-like adhesive such as an anisotropic conductive film, the film-like adhesive containing the conductive particles with insulating particles is used. A film-like adhesive that does not contain conductive particles with insulating particles may be laminated. However, as described above, the anisotropic conductive material according to the present invention is preferably in the form of a paste, and is preferably an anisotropic conductive paste. The paste form includes liquid.

  In 100% by weight of the anisotropic 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 It is 99.99 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 connection reliability of the connection target member in which the conductive particles with insulating particles are efficiently arranged between the electrodes and connected by the anisotropic conductive material The nature becomes even higher.

  In 100% by weight of the anisotropic conductive material, the content of the conductive particles with insulating particles is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, preferably 20% by weight or less, more preferably Is 10% by weight or less. When the content of the conductive particles with insulating 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)
By connecting the connection target members using the conductive particles with insulating particles according to the present invention, or using the anisotropic conductive material including the conductive particles with insulating particles according to the present invention and a binder resin. A connection structure can be obtained.

  The connection structure includes a first connection target member, a second connection target member, and a connection portion connecting the first and second connection target members, and the connection portion is an insulating material according to the present invention. It is preferable that the connection structure is formed of conductive particles with conductive particles or an anisotropic conductive material including the conductive particles with insulating particles and a binder resin. In the case where conductive particles with insulating particles are used, the connecting portion itself is conductive particles with insulating particles. That is, the first and second connection target members are connected by the conductive particles with insulating particles.

  FIG. 5 is a front cross-sectional view schematically showing a connection structure using conductive particles with insulating particles according to the first embodiment of the present invention.

  A connection structure 81 shown in FIG. 5 includes a first connection target member 82, a second connection target member 83, and a connection portion 84 connecting the first and second connection target members 82 and 83. Prepare. The connecting portion 84 is formed of an anisotropic conductive material including the conductive particles 1 with insulating particles. Specifically, it is formed by curing an anisotropic conductive material including a plurality of conductive particles 1 with insulating particles. In FIG. 5, the conductive particles 1 with insulating particles are schematically shown for convenience of illustration.

  The first connection target member 82 has a plurality of electrodes 82b on the upper surface 82a. The second connection target member 83 has a plurality of electrodes 83b on the lower surface 83a. The electrode 82b and the electrode 83b are electrically connected by one or a plurality of conductive particles 1 with insulating particles. Therefore, the first and second connection target members 82 and 83 are electrically connected by the conductive particles 1 with insulating particles.

The manufacturing method of the connection structure is not particularly limited. As an example of the manufacturing method of the connection structure, the anisotropic conductive material is disposed between the first connection target member and the second connection target member to obtain a laminate, and then the laminate is heated. And a method of applying pressure. 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.

  Specific examples of the connection target member include electronic components such as a semiconductor chip, a capacitor, and a diode, and circuit components such as a printed board, a flexible printed board, and a glass board. The anisotropic conductive material is preferably an anisotropic conductive material for connecting electronic components. The anisotropic conductive material is a paste-like anisotropic conductive paste, and is preferably applied on the connection target member in a paste-like state.

  Examples of the electrode 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 metal oxide 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
Conductive particles (average particle diameter: 3.01 μm, conductive layer thickness: 0.1 μm) having a nickel plating layer (conductive layer) formed on the surface of divinylbenzene resin particles were prepared.

  Moreover, the surface of the silica particle (average particle diameter 250nm) produced using the sol-gel method was coat | covered with vinyltriethoxysilane, and the insulating particle which has a vinyl group on the surface was obtained as an insulating particle main body.

  In 200 mL of water, 1 part by weight of the insulating particle main body, 5 parts by weight of methacrylic acid as a polymer compound, 0.3 part by weight of ethylene glycol dimethacrylate as a compound as a polymer compound, After fully emulsifying 0.1 parts by weight of an initiator (“V-50” manufactured by Wako Pure Chemical Industries, Ltd.) with an ultrasonic irradiator, the temperature was raised to 70 ° C. with sufficient stirring with a three-one motor, and 70 ° C. For 6 hours to polymerize the monomer.

  Then, it cooled, solid-liquid separation was performed twice with the centrifuge, the excess monomer was removed by washing | cleaning, and the insulating particle by which the whole surface was coat | covered with the high molecular compound was obtained. Next, the obtained insulating particles were dispersed in 30 mL of pure water to obtain a dispersion of insulating particles.

  When this dispersion was measured by the microtrack particle size distribution diameter, the average particle diameter of the insulating particles covering the polymer layer was 410 nm.

  A 1 L separable flask was charged with 250 mL of pure water, 50 mL of ethanol, and 15 parts by weight of the conductive particles, and stirred sufficiently to obtain a liquid containing conductive particles. To the liquid containing the conductive particles, the dispersion liquid of the insulating particles was dropped over 10 minutes while applying ultrasonic waves, and then heated to 40 ° C. and stirred for 1 hour. Then, it filtered and it was made to dry at 100 degreeC with a vacuum dryer for 8 hours, and the electroconductive particle with an insulating particle was obtained.

(Example 2)
Example 1 except that when obtaining insulating particles whose entire surface was coated with a polymer compound, the compound to be the polymer compound was changed to 15 parts by weight of methacrylic acid and 0.5 parts by weight of divinylbenzene. In the same manner, conductive particles with insulating particles were obtained.

  When the dispersion was measured by the microtrack particle size distribution diameter in the same manner as in Example 1, the average particle diameter of the insulating particles covering the polymer layer was 880 nm.

(Example 3)
The surface of the silica particles was coated with methacryloxypropyltriethoxysilane to obtain insulating particles having methacryloyl groups on the surface as the insulating particle main body, and the entire surface was made of a polymer compound using the insulating particle main body. When obtaining the coated insulating particles, the same procedure as in Example 1 was performed except that the compound to be a polymer compound was changed to 5 parts by weight of vinyl acetate and 0.3 parts by weight of N, N-methylenebisacrylamide. Thus, conductive particles with insulating particles were obtained.

  When the dispersion was measured by the microtrack particle size distribution diameter in the same manner as in Example 1, the average particle diameter of the insulating particles covering the polymer layer was 390 nm.

Example 4
Conductivity in which nickel powder (100 nm) is attached as a core material to the surface of divinylbenzene resin particles, and a nickel plating layer (conductive layer) is formed on the surface of divinylbenzene particles to which nickel powder is attached Conductive particles with insulating particles were obtained in the same manner as in Example 1 except that particles (average particle size: 3.03 μm, conductive layer thickness: 0.11 μm) were used.

(Example 5)
Conductive particles with insulating particles were obtained in the same manner as in Example 1 except that the input amount of the conductive particles when attaching the insulating particles was changed to 25 parts by weight.

(Example 6)
Conductive particles with insulating particles were obtained in the same manner as in Example 1 except that the input amount of the conductive particles when attaching the insulating particles was changed to 8 parts by weight.

(Example 7)
Using the physical / mechanical hybridization method, the insulating particles produced in Example 1 were attached to the conductive particles prepared in Example 1 to obtain conductive particles with insulating particles.

(Comparative Example 1)
Conductive particles with insulating particles were obtained in the same manner as in Example 1 except that the surface of the insulating particle main body was not coated with the polymer compound.

  That is, when the insulating particles are attached to the surface of the conductive particles, the insulating particles (not coated with the polymer compound) having the vinyl group on the surface are used as pure water as a dispersion of the insulating particles. A dispersion liquid dispersed in 30 mL was used.

(Comparative Example 2)
Conductive particles with insulating particles were obtained in the same manner as in Example 1 except that when the insulating particles whose entire surface was coated with the polymer compound were obtained, the amount of methacrylic acid was changed to 1 part by weight.

  When the dispersion was measured by the microtrack particle size distribution diameter in the same manner as in Example 1, the average particle diameter of the insulating particles covering the polymer layer was 240 nm.

(Comparative Example 3)
Conductive particles with insulating particles were obtained in the same manner as in Example 1 except that when the insulating particles whose entire surface was coated with the polymer compound were obtained, the amount of methacrylic acid was changed to 25 parts by weight.

  When the dispersion was measured by the microtrack particle size distribution diameter in the same manner as in Example 1, the average particle diameter of the insulating particles covering the polymer layer was 1270 nm.

(Evaluation of Examples 1-7 and Comparative Examples 1-3)
(1) Coverage rate of conductive particles with insulating particles and residual rate of insulating particles Before sonication, 100 conductive particles with insulating particles of Examples and Comparative Examples were observed by observation with an SEM. . The coverage X1 which is the projected area of the portion covered with the insulating particles in the entire surface area of the conductive particles in the conductive particles with the insulating particles was determined.

  Next, 3 parts by weight of conductive particles with insulating particles was added to 100 parts by weight of ethanol to obtain a conductive particle-containing liquid with insulating particles. The conductive particle-containing liquid with insulating particles was subjected to ultrasonic treatment while being stirred for 5 minutes at 20 ° C. and 38 kHz with an ultrasonic cleaner having an output of 400 W. After the ultrasonic treatment, 100 conductive particles with insulating particles are observed by observation with an SEM, and the portion of the conductive particles with insulating particles covered by the insulating particles occupying the entire surface area of the conductive particles. The coverage X2, which is the projected area, was determined. The remaining rate of the insulating particles was obtained from the following formula (1) from the coverage X1 and the coverage X2.

  Residual rate of insulating particles (%) = (coverage ratio X2 after ultrasonic treatment / coverage ratio X1 before ultrasonic treatment) × 100 Formula (1)

(2) Preparation of connection structure The conductive particles with insulating particles of Examples and Comparative Examples were added to and dispersed in “Struct Bond XN-5A” manufactured by Mitsui Chemicals so that the content would be 10% by weight. An anisotropic conductive paste was obtained.

A transparent glass substrate having an ITO electrode pattern with an L / S of 20 μm / 20 μm formed on the upper surface was prepared. Further, a semiconductor chip was prepared in which a copper electrode pattern having an L / S of 20 μm / 20 μm and an electrode area of 2000 μm ² was formed on the lower surface.

  On the transparent glass substrate, the obtained anisotropic conductive paste was applied to a thickness of 30 μm to form an anisotropic conductive paste layer. Next, the semiconductor chip was stacked on the anisotropic conductive paste layer so that the electrodes face each other. Then, while adjusting the temperature of the head so that the temperature of the anisotropic conductive paste layer becomes 185 ° C., a pressure heating head is placed on the upper surface of the semiconductor chip and a pressure of 1 MPa is applied to form the anisotropic conductive paste layer. Completely cured at 185 ° C. to obtain a connection structure.

(3) Conductivity evaluation (between upper and lower electrodes)
The connection resistance between the upper and lower electrodes of the obtained connection structure was measured by a four-terminal method. The average value of the two connection resistances was calculated. Note that the connection resistance can be obtained by measuring the voltage when a constant current is passed from the relationship of voltage = current × resistance. The case where the average value of the connection resistance was 2.0Ω or less was judged as “◯”, and the case where the average value of the connection resistance exceeded 2.0Ω was judged as “X”.

(4) Insulation evaluation (between adjacent electrodes in the horizontal direction)
In the obtained connection structure, the presence or absence of leakage between adjacent electrodes was evaluated by measuring resistance with a tester. When the resistance exceeded 500 MΩ, it was judged that there was no leak and the result was judged as “◯”, and when the resistance was 500 MΩ or less, it was judged that there was a leak and the result was judged as “X”.

  The results are shown in Table 1 below.

  In addition, in the insulating particles obtained in Examples 1 to 7, it was confirmed that the layer formed of the polymer compound was higher in flexibility than the silica particles by measuring the compression recovery rate of the insulating particles. did.

  Moreover, in the electroconductive particle with an insulating particle of Examples 1-6, it confirmed that the polymer compound did not adhere to parts other than the part to which the insulating particle of the surface of electroconductive particle has adhered. . In Example 7, since the physical / mechanical hybridization method is used, there is a portion where the polymer compound is attached to a portion other than the portion where the insulating particles are attached on the surface of the conductive particles. It was.

DESCRIPTION OF SYMBOLS 1 ... Conductive particle with insulating particle 2 ... Conductive particle 3 ... Insulating particle 5 ... Insulating particle body 6 ... Layer 11 ... Base material particle 12 ... Conductive layer 21 ... Conductive particle 22 with insulating particle ... Conductivity Particle 31 ... Conductive layer 32 ... Core substance 33 ... Protrusion 41 ... Conductive particle 42 with insulating particle ... Conductive particle 43 ... Insulating particle 51 ... Conductive layer 52 ... Protrusion 61 ... Conductive particle 62 with insulating particle ... Coating 81 ... Connection structure 82 ... First connection object member 82a ... Upper surface 82b ... Electrode 83 ... Second connection object member 83a ... Lower surface 83b ... Electrode 84 ... Connection part

Claims (8)

Conductive particles having at least a conductive layer on the surface;
A plurality of insulating particles attached to the surface of the conductive particles,
Conductive particles with insulating particles, wherein the average particle size of the insulating particles exceeds 1/10 of the particle size of the conductive particles and is 1/3 or less.   The conductive particles with insulating particles according to claim 1, wherein a particle diameter of the conductive particles is 1 μm or more and 5 μm or less.   The conductive particles with insulating particles according to claim 1 or 2, wherein an average particle size of the insulating particles exceeds 1/8 of a particle size of the conductive particles.   The insulating particle according to any one of claims 1 to 3, wherein the insulating particle has an insulating particle body and a layer covering at least a partial region of the surface of the insulating particle body. With conductive particles.   The conductive particles with insulating particles according to claim 1, wherein the insulating particles are attached to the surface of the conductive particles by a chemical method.   The anisotropic conductive material containing the electroconductive particle with an insulating particle of any one of Claims 1-5, and binder resin.   The anisotropic conductive material according to claim 6, which is a paste-like anisotropic conductive paste. A first connection target member, a second connection target member, and a connection part connecting the first and second connection target members;
The said connection part is formed with the electroconductive particle with an insulating particle of any one of Claims 1-5, or anisotropic conductivity containing this electroconductive particle with an insulating particle and binder resin. A connection structure made of a material.

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