JP2014017248A - Conductive material, production method of conductive material, and connection structure - Google Patents

Abstract

Aggregation of a plurality of first conductive particles hardly occurs, and further, when used for connection between electrodes, a conductive material capable of improving conduction reliability and insulation reliability, and the use of the conductive material A connection structure is provided.
A conductive material according to the present invention includes first conductive particles having solder on a conductive surface, solder particles 21 having an average particle diameter smaller than that of the first conductive particles, and a binder resin. Including. The connection structure 51A according to the present invention includes a first connection target member 52 having a first electrode 52a on the surface, a second connection target member 53 having a second electrode 53a on the surface, And a connection portion 54 </ b> A connecting the two connection target members 52 and 53. The connecting portion 54A is made of the conductive material. The first and second electrodes 52a and 53a are electrically connected by the first conductive particles 21B or the solder particles 21 included in the conductive material.
[Selection] Figure 1

Description

  The present invention relates to a conductive material used for electrical connection between electrodes such as a flexible printed circuit board, a glass substrate, a semiconductor chip, and a glass epoxy substrate, and a method for manufacturing the conductive material. The present invention also relates to a connection structure using the conductive material.

  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.

  In order to obtain various connection structures, the anisotropic conductive material is, for example, a connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)) or a connection between a semiconductor chip and a flexible printed circuit board (COF ( Chip on Film)), connection between a semiconductor chip and a glass substrate (COG (Chip on Glass)), connection between a flexible printed circuit board and a glass epoxy substrate (FOB (Film on Board)), and the like.

  For example, when the electrode of the semiconductor chip and the electrode of the glass substrate are electrically connected by the anisotropic conductive material, an anisotropic conductive material containing conductive particles is disposed on the glass substrate. Next, the semiconductor chips are stacked, and heated and pressurized. As a result, the anisotropic conductive material is cured, and the electrodes are electrically connected via the conductive particles to obtain a connection structure.

  As an example of the anisotropic conductive material, the following Patent Document 1 discloses an anisotropic conductive material including an adhesive composition that flows by heating, first particles, and second particles. Yes. The first particles include a core mainly composed of a low melting point metal having a melting point of 130 to 250 ° C., and a resin composition that covers the surface of the core and has a softening point lower than the melting point of the low melting point metal. And an insulating layer formed. The second particle has an average particle size smaller than that of the core in the first particle. The main component of the second particle is a material having a melting point or a softening point higher than the melting point of the low melting point metal.

  Patent Document 2 below discloses an anisotropic conductive adhesive in which conductive particles are dispersed in an insulating adhesive. The conductive particles are two or more kinds of conductive particles having different average particle diameters, and these conductive particles are insulating coated conductive particles coated with an insulating resin insoluble in the insulating adhesive. .

JP 2009-277852 A Japanese Patent Laid-Open No. 11-244104

  When a conventional anisotropic conductive material as described in Patent Document 1 is used for connection between upper and lower electrodes, conduction between adjacent electrodes in the lateral direction that should not be connected occurs, resulting in poor insulation. May occur. In particular, when the electrodes are connected by conductive particles having solder on the conductive surface, insulation failure tends to occur. On the other hand, when the conductive surfaces are connected between the electrodes by conductive particles that are not solder, the conductive material does not spread out on the electrode surfaces like solder, so the conduction reliability and connection between the electrodes Reliability is lowered.

  Specifically, Patent Document 2 only describes an anisotropic conductive adhesive using conductive particles in which an Au / Ni plating layer is formed on the surface of resin particles as the conductive particles. .

  In recent years, with the downsizing of electronic devices, the distance between the line (L) where the electrode is formed and the space (S) where the electrode is not formed has become narrower. For example, there is an increasing need to electrically connect fine electrodes having L / S of 100 μm or less / 100 μm or less. When electrically connecting electrodes having a small L / S, the conventional anisotropic conductive material has a problem that insulation failure is particularly likely to occur.

  In the conventional anisotropic conductive material, a plurality of conductive particles may aggregate in the anisotropic conductive material. If a plurality of conductive particles are aggregated, there is a problem that insulation failure is more likely to occur.

  An object of the present invention is to prevent agglomeration of a plurality of first conductive particles and to further improve the conduction reliability and insulation reliability when the electrodes are connected to each other. In addition, a connection structure using the conductive material is provided.

  According to a wide aspect of the present invention, there is provided a conductive material including first conductive particles having solder on a conductive surface, solder particles having an average particle diameter smaller than that of the first conductive particles, and a binder resin. Material is provided.

  According to a wide aspect of the present invention, first conductive particles having solder on a conductive surface, solder particles having an average particle diameter smaller than that of the first conductive particles, and a binder resin are mixed. There is provided a method for producing a conductive material, which obtains a conductive material containing the first conductive particles, the solder particles, and the binder resin.

  The ratio of the average particle diameter of the solder particles to the average particle diameter of the first conductive particles is preferably 0.1 or more and 0.7 or less. The average particle diameter of the first conductive particles is preferably 1 μm or more and 20 μm or less. The CV value of the particle diameter of the first conductive particles is preferably 20% or less.

  On the specific situation with the electrically-conductive material which concerns on this invention, and the manufacturing method of the electrically-conductive material which concerns on this invention, a said 1st electroconductive particle is a solder particle.

  In a specific aspect of the conductive material according to the present invention and the method for producing the conductive material according to the present invention, the first conductive particles are base particles and a solder layer disposed on the surface of the base particles With.

  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, and the A connecting portion that connects a second connection target member, the connecting portion is formed of the conductive material described above, and the first electrode and the second electrode are the conductive material. A connection structure is provided which is electrically connected by the first conductive particles or the solder particles included in the structure.

  Since the conductive material according to the present invention includes first conductive particles having solder on a conductive surface, solder particles having an average particle diameter smaller than that of the first conductive particles, and a binder resin, Aggregation of the plurality of first conductive particles in the resin can be suppressed. Furthermore, when the electrodes are connected using the conductive material according to the present invention, the conduction reliability and the insulation reliability can be improved.

  The method for producing a conductive material according to the present invention includes first conductive particles having solder on a conductive surface, solder particles having an average particle diameter smaller than that of the first conductive particles, and a binder resin. Since a conductive material is obtained, when the electrodes are connected using the obtained conductive material, conduction reliability and insulation reliability can be improved.

FIG. 1 is a front sectional view schematically showing a connection structure using a conductive material according to the first embodiment of the present invention. FIG. 2 is a front sectional view schematically showing a connection structure using a conductive material according to the second embodiment of the present invention. FIG. 3 is a front sectional view schematically showing an enlarged connection portion between the first conductive particles and the electrodes in the connection structure shown in FIG. 2. FIG. 4 is a cross-sectional view showing an example of conductive particles. FIG. 5 is a cross-sectional view showing a first modification of the first conductive particles. FIG. 6 is a cross-sectional view showing a second modification of the first conductive particles.

  Details of the present invention will be described below.

  The conductive material according to the present invention includes first conductive particles, solder particles (second conductive particles), and a binder resin. The first conductive particles have solder on the conductive surface. The average particle diameter of the solder particles is smaller than the average particle diameter of the first conductive particles.

  In the method for producing a conductive material according to the present invention, the first conductive particles, solder particles (second conductive particles) having an average particle diameter smaller than that of the first conductive particles, and a binder resin are used. By mixing, a conductive material containing the first conductive particles, the solder particles, and the binder resin is obtained.

  In the conductive material according to the present invention and the method for producing a conductive material according to the present invention, the above-described configuration is adopted, and therefore, the aggregation of the plurality of first conductive particles in the binder resin can be suppressed. In particular, the use of solder particles having an average particle diameter smaller than that of the first conductive particles makes it difficult for the plurality of first conductive particles to aggregate in the binder resin.

  Further, in the conductive material according to the present invention and the method for producing the conductive material according to the present invention, the above-described configuration is adopted. Therefore, when the electrodes are connected using the conductive material according to the present invention, the conduction reliability is improved. In addition, the insulation reliability can be improved. For example, when the conductive material according to the present invention is used for the connection between the upper and lower electrodes, the conduction reliability between the upper and lower electrodes can be improved, and further, between the electrodes adjacent in the lateral direction that should not be connected. Conduction can be made difficult to occur, and it is possible to effectively suppress the occurrence of insulation failure.

  In particular, when the L / S indicating the line (L) where the electrode is formed and the space (S) where the electrode is not formed is 100 μm or less / 100 μm or less, the insulation reliability is effective. When L / S is 75 μm or less / 75 μm or less, the insulation reliability can be further effectively improved, and L / S is 62.5 μm or less / 62.5 μm or less. In this case, the insulation reliability can be further effectively improved, and the insulation reliability can be particularly effectively improved when L / S is 50 μm or less / 50 μm or less.

  Further, since the conduction reliability can be improved by the conductive material according to the present invention, the line (L) where the electrode is formed is preferably 100 μm or less, more preferably 75 μm or less, and even more preferably 62.5 μm. Hereinafter, it is particularly preferably 50 μm or less. The line (L) is preferably larger than the average particle size of the first conductive particles, more preferably 1.1 times or more of the average particle size of the first conductive particles, and more than 2 times. More preferably, it is more preferably 3 times or more.

  In addition, since the insulation reliability can be improved by the conductive material according to the present invention, the space (S) where the electrode is not formed is preferably 100 μm or less, more preferably 75 μm or less, and even more preferably 62.5 μm. Hereinafter, it is particularly preferably 50 μm or less. The space (S) is preferably larger than the average particle size of the first conductive particles, more preferably 1.1 times or more of the average particle size of the first conductive particles, and more than 2 times. More preferably, it is more preferably 3 times or more.

  Furthermore, in the conductive material according to the present invention, since the conductive surface of the first conductive particles is solder, it is possible to wet and spread the solder on the electrode surface. And connection reliability can be improved.

  When the conductive surface of the first conductive particles is not solder, or when conductive particles other than solder particles are used instead of the solder particles, the conduction reliability is lowered. In the present invention, the conductive surface of the first conductive particles is a solder, and the fact that the particles having an average particle diameter smaller than that of the first conductive particles are solder particles improves the conduction reliability. This is an important configuration that exhibits new functions and actions.

  The ratio of the average particle diameter of the solder particles to the average particle diameter of the first conductive particles (the average particle diameter of the solder particles / the average particle diameter of the first conductive particles) is preferably 0.06 or more. Preferably it is 0.1 or more, preferably 0.8 or less, more preferably 0.7 or less. When the ratio (average particle diameter of solder particles / average particle diameter of first conductive particles) is not less than the above lower limit and not more than the above upper limit, the aggregation of the first conductive particles is further less likely to occur, and the insulation reliability The nature becomes even higher. The ratio (average particle diameter of solder particles / average particle diameter of first conductive particles) is particularly preferably 0.1 or more and 0.7 or less.

  The average particle diameter of the first conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, still more preferably 5 μm or more, particularly preferably 10 μm or more, preferably 100 μm or less, more preferably 30 μm or less, and further It is preferably 20 μm or less, particularly preferably 15 μm or less, and most preferably 10 μm or less. When the average particle diameter of the first conductive particles is not less than the above lower limit and not more than the above upper limit, the aggregation of the first conductive particles is less likely to occur, and the insulation reliability is further enhanced. The average particle diameter of the first conductive particles is particularly preferably 5 μm or more and 10 μm or less.

  The “average particle diameter” of the first conductive particles and the solder particles respectively represents the number average particle diameter. The average particle diameter of the first conductive particles and the solder particles is obtained by observing 50 arbitrary first conductive particles or 50 solder particles with an electron microscope or an optical microscope, and calculating an average value. Desired.

  From the viewpoint of further suppressing the aggregation of the first conductive particles, the CV value of the particle diameter of the first conductive particles is preferably 40% or less, more preferably 20% or less. When the CV value of the particle diameter of the first conductive particles is not more than the above upper limit, aggregation of the first conductive particles can be further suppressed. As a result, the insulation reliability can be further improved.

  The CV value (coefficient of variation) of the particle diameter is represented by the following formula.

CV value (%) = (σn / Dn) × 100
σn: standard deviation of particle diameter of first conductive particles Dn: number average particle diameter of first conductive particles

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

(Conductive particles)
FIG. 4 is a cross-sectional view showing an example of conductive particles.

  The conductive particles shown in FIG. 4 are solder particles 21. The solder particles 21 are formed only by solder. The solder particles 21 do not have base particles in the core and are not core-shell particles. The solder particles 21 are formed of solder at both the central portion and the outer surface. If the average particle diameter is within an appropriate range, the solder particles 21 can be used as the first conductive particles. The solder particles 21 can be used as the second conductive particles as long as the average particle diameter is within an appropriate range.

  FIG. 5 is a cross-sectional view showing a first modification of the first conductive particles.

  A first conductive particle 1 shown in FIG. 5 includes a base particle 2 and a conductive layer 3 disposed on the surface of the base particle 2. The conductive layer 3 covers the surface of the base particle 2. The first conductive particles 1 are coated particles in which the surface of the base particle 2 is coated with the conductive layer 3.

  The conductive layer 3 includes a second conductive layer 3A and a solder layer 3B (first conductive layer) disposed on the surface of the second conductive layer 3A. The first conductive particles 1 include a second conductive layer 3A between the base particle 2 and the solder layer 3B. Accordingly, the first conductive particles 1 are composed of the base particles 2, the second conductive layer 3A disposed on the surface of the base particles 2, and the solder disposed on the surface of the second conductive layer 3A. Layer 3B. Thus, the conductive layer 3 may have a multilayer structure, or may have a laminated structure of two or more layers.

  As described above, the conductive layer 3 in the first conductive particle 1 has a two-layer structure. As in the second modification shown in FIG. 6, the first conductive particles 11 may have a solder layer 12 as a single conductive layer. The first conductive particles 11 include base material particles 2 and a solder layer 12 disposed on the surface of the base material particles 2.

  The first conductive particles may also be solder particles. In this case, two types of solder particles having different particle diameters (first solder particles (first conductive particles) and second solder particles (second conductive particles)) are used. In the present invention, the first conductive particles having the solder on the conductive surface are preferably solder 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 substrate particles may be copper particles.

  The substrate particles are preferably resin particles formed of a resin. When connecting between electrodes using electroconductive particle, after arrange | positioning electroconductive particle between electrodes, 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 still higher.

  Examples of the resin for forming 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; Alkylene terephthalate, 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, polyethylene terephthalate, Polysulfone, polyphenylene oxide, polyacetal, polyimide, polyamide Bromide, polyether ether ketone, polyether sulfone, divinyl benzene polymer, and divinylbenzene copolymer, and the like. Examples of the divinylbenzene copolymer include divinylbenzene-styrene copolymer and divinylbenzene- (meth) acrylic acid ester copolymer. Since the hardness of the resin 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.

  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 di (meth) acrylate, 1,4-butanediol di (meth) acrylate; triallyl (iso) cyanurate, tria Rutorimeriteto, divinylbenzene, diallyl phthalate, diallyl acrylamide, diallyl ether, .gamma. (meth) acryloxy propyl trimethoxy silane, trimethoxy silyl styrene, include silane-containing monomers such as vinyltrimethoxysilane.

  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 polymerizing 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, examples of the inorganic material for forming the substrate particles include silica and carbon black. Although it does not specifically limit as the particle | grains formed with the said silica, For example, after hydrolyzing the silicon compound which has two or more hydrolysable alkoxysil groups, and forming a crosslinked polymer particle, it calcinates as needed. 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 for forming the metal particles include silver, copper, nickel, silicon, gold, and titanium. When the base material particles are metal particles, the metal particles are preferably copper particles. However, the substrate particles are preferably not metal particles.

  The method for forming the conductive layer on the surface of the base particle and the method for forming the solder layer on the surface of the base particle or the surface of the second conductive layer are not particularly limited. As a method of forming the conductive layer and the solder layer, for example, a method by electroless plating, a method by electroplating, a method by physical collision, a method by mechanochemical reaction, a method by physical vapor deposition or physical adsorption, In addition, a method of coating the surface of the particles with a metal powder or a paste containing a metal powder and a binder may be used. Among these, a method using electroless plating, electroplating, or physical collision is preferable. Examples of the method by physical vapor deposition include methods such as vacuum vapor deposition, ion plating, and ion sputtering. Further, in the method based on the physical collision, for example, a sheeter composer (manufactured by Tokuju Kogakusha Co., Ltd.) or the like is used.

  The melting point of the base particle is preferably higher than the melting point of the solder layer. The melting point of the substrate particles is preferably higher than 160 ° C, more preferably higher than 300 ° C, still more preferably higher than 400 ° C, and particularly preferably higher than 450 ° C. The melting point of the substrate particles may be less than 400 ° C. The melting point of the substrate particles may be 160 ° C. or less. The softening point of the substrate particles is preferably 260 ° C. or higher. The softening point of the substrate particles may be less than 260 ° C.

  The average particle size of the solder particles is preferably smaller than the average particle size of the base particles in the first conductive particles.

  The first conductive particles may have a single solder layer. The first conductive particles may have a plurality of conductive layers (solder layer, second conductive layer). That is, in the conductive particles, two or more conductive layers may be stacked.

  The solder is preferably a low melting point metal having a melting point of 450 ° C. or lower. The solder layer is preferably a low melting point metal layer having a melting point of 450 ° C. or lower. The low melting point metal layer is a layer containing a low melting point metal. The solder particles are preferably low melting point metal particles having a melting point of 450 ° C. or lower. The low melting point metal particles are particles containing a low melting point metal. The low melting point metal is a metal having a melting point of 450 ° C. or lower. The melting point of the low melting point metal is preferably 300 ° C. or lower, more preferably 160 ° C. or lower. The solder layer and the solder particles preferably contain tin. In 100% by weight of the metal contained in the solder layer and 100% by weight of the metal contained in the solder particles, the tin content is preferably 30% by weight or more, more preferably 40% by weight or more, and even more preferably 70% by weight. Above, particularly preferably 90% by weight or more. When the content of tin in the solder layer and the solder particles is equal to or higher than the lower limit, the connection reliability between the first conductive particles and the electrodes is further increased.

  The tin content is determined using a high frequency inductively coupled plasma optical emission spectrometer (“ICP-AES” manufactured by Horiba, Ltd.) or a fluorescent X-ray analyzer (“EDX-800HS” manufactured by Shimadzu). It can be measured.

  By using the 1st electroconductive particle which has the said solder on the electroconductive surface, a solder fuse | melts and it joins to an electrode, and a solder conducts between electrodes. For example, since the solder and the electrode are not in point contact but in surface contact, the connection resistance is lowered. In addition, the use of the first conductive particles having solder on the conductive surface increases the bonding strength between the solder and the electrode. As a result, peeling between the solder and the electrode is further less likely to occur. Reliability is effectively increased.

  The low melting point metal constituting the solder layer and the solder particles is not particularly limited. The low melting point metal is preferably tin or an alloy containing tin. Examples of the alloy include a tin-silver alloy, a tin-copper alloy, a tin-silver-copper alloy, a tin-bismuth alloy, a tin-zinc alloy, and a tin-indium alloy. Especially, since it is excellent in the wettability with respect to an electrode, it is preferable that the said low melting metal is a tin, a tin-silver alloy, a tin-silver-copper alloy, a tin-bismuth alloy, and a tin-indium alloy. More preferred are a tin-bismuth alloy and a tin-indium alloy.

  Although the material which comprises the said solder layer and the said solder particle is not specifically limited, Based on JISZ3001: welding term, it is preferable that it is a filler material whose liquidus is 450 degrees C or less. As a composition of the said solder layer and the said solder particle, the metal composition containing zinc, gold | metal | money, lead, copper, tin, bismuth, indium etc. is mentioned, for example. Among them, a tin-indium system (117 ° C. eutectic) or a tin-bismuth system (139 ° C. eutectic) which is low-melting and lead-free is preferable. That is, the solder layer and the solder particles preferably do not contain lead, and preferably contain tin and indium, or contain tin and bismuth.

  In order to further increase the bonding strength between the solder and the electrode, the solder layer and the solder particles are nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, cobalt, bismuth, Metals such as manganese, chromium, molybdenum, and palladium may be included. Moreover, from the viewpoint of further increasing the bonding strength between the solder and the electrode, the solder layer and the solder particles preferably contain nickel, copper, antimony, aluminum, or zinc. From the viewpoint of further increasing the bonding strength between the solder and the electrode, the content of these metals for increasing the bonding strength is preferably 0.0001% by weight or more in the solder layer and 100% by weight of the solder particles, Preferably it is 1 weight% or less.

  The melting point of the second conductive layer is preferably higher than the melting point of the solder layer. The melting point of the second conductive layer is preferably above 160 ° C, more preferably above 300 ° C, even more preferably above 400 ° C, even more preferably above 450 ° C, particularly preferably above 500 ° C, most preferably Preferably it exceeds 600 degreeC. Since the solder layer has a low melting point, it melts during conductive connection. The second conductive layer is preferably not melted at the time of conductive connection. The conductive particles are preferably used after melting solder, preferably used after melting the solder layer, and used without melting the second conductive layer while melting the solder layer. It is preferred that Since the melting point of the second conductive layer is higher than the melting point of the solder layer, only the solder layer can be melted without melting the second conductive layer at the time of conductive connection.

  The absolute value of the difference between the melting point of the solder layer and the melting point of the second conductive layer exceeds 0 ° C, preferably 5 ° C or more, more preferably 10 ° C or more, still more preferably 30 ° C or more, particularly preferably Is 50 ° C. or higher, most preferably 100 ° C. or higher.

  The second conductive layer preferably contains a metal. The metal constituting the second conductive layer is not particularly limited. Examples of the metal include gold, silver, copper, platinum, palladium, zinc, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium and cadmium, and alloys thereof. 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.

  The second conductive layer is preferably a nickel layer, a palladium layer, a copper layer, or a gold layer, more preferably a nickel layer or a gold layer, and even more preferably a copper layer. The conductive particles preferably have a nickel layer, a palladium layer, a copper layer, or a gold layer, more preferably have a nickel layer or a gold layer, and still more preferably have a copper layer. By using the conductive particles having these preferable conductive layers for the connection between the electrodes, the connection resistance between the electrodes is further reduced. In addition, a solder layer can be more easily formed on the surface of these preferable conductive layers.

  The average thickness of the solder layer is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 10 μm or less, more preferably 1 μm or less, and still more preferably 0.3 μm or less. When the average thickness of the solder layer is not less than the above lower limit and not more than the above upper limit, sufficient conductivity can be obtained, and the conductive particles do not become too hard, and the conductive particles are sufficiently deformed when connecting the electrodes. To do. The average thickness of the solder layer is an average of the thicknesses of the solder layers in the plurality of first conductive particles contained in the conductive material.

  The average thickness of the second conductive layer is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 10 μm or less, more preferably 1 μm or less, and still more preferably 0.3 μm or less. When the average thickness of the second conductive layer is not less than the above lower limit and not more than the above upper limit, the connection resistance between the electrodes is further reduced. The average thickness of the second conductive layer is an average of the thicknesses of the second conductive layers in the plurality of first conductive particles included in the conductive material.

  When the first conductive particles are solder particles, the first conductive particles (solder particles) and the relatively small solder particles (second conductive particles) have a first conductivity. The absolute value of the difference between the melting point of the solder of the particles (solder particles) and the melting point of the solder of the relatively small solder particles (second conductive particles) is preferably greater than 0 ° C., preferably 30 ° C. or less. is there. If such a melting point relationship is satisfied, both conduction reliability and insulation reliability are improved in a well-balanced manner.

  When the first conductive particles are solder particles, the average particle size of the first conductive particles (solder particles) and the average particle size of relatively small solder particles (second conductive particles) The absolute value of the difference is preferably 0.06 or more, and preferably 0.8 or less. The average particle diameter of relatively small solder particles (second conductive particles) is preferably 2 μm or more, more preferably 5 μm or more, preferably 20 μm or less, more preferably 15 μm or less. When such a relationship of the average particle diameter is satisfied, both the conduction reliability and the insulation reliability are improved with a good balance.

(Conductive material)
The conductive material according to the present invention includes the first conductive particles, the solder particles, and a binder resin. The conductive material according to the present invention includes a plurality of the first conductive particles. The conductive material according to the present invention includes a plurality of the solder particles. The conductive material according to the present invention is preferably an anisotropic conductive material.

  The binder resin is not particularly limited. In general, an insulating resin is used as the binder resin. The binder resin preferably contains a thermoplastic compound or contains a thermosetting component. The thermosetting component preferably contains a curable compound that can be cured by heating and a thermosetting agent. The binder resin preferably contains a curable compound that can be cured by heating and a thermosetting agent. The binder resin may contain a thermoplastic compound, or may contain a curable compound that can be cured by heating.

  The curing temperature of the curable compound curable by heating is preferably higher by 1 ° C. than the melting point of the solder in the first conductive particles, and is higher than the melting point of the solder particles (second conductive particles). Is preferably 1 ° C. or higher. When such a curing temperature is satisfied, both conduction reliability and insulation reliability are improved in a well-balanced manner. The curing temperature of the curable compound curable by heating is preferably 40 ° C. or lower.

  In 100% by weight of the conductive material, the total content of the first conductive particles and the solder particles is preferably 1% by weight or more, more preferably 2% by weight or more, and even more preferably 10% by weight or more. It is preferably 20% by weight or more, most preferably 30% by weight or more, preferably 80% by weight or less, more preferably 60% by weight or less, and still more preferably 50% by weight or less. When the total content of the first conductive particles and the solder particles is not less than the above lower limit and not more than the above upper limit, it is easy to dispose a large amount of the first conductive particles between the electrodes, and the conduction reliability The nature becomes even higher. Moreover, since content, such as a thermosetting component, becomes moderate, the conduction | electrical_connection reliability between electrodes becomes still higher. From the viewpoint of further improving the conduction reliability, it is preferable that the total content of the conductive particles and the solder particles is large.

  In the conductive material, the weight ratio of the first conductive particles to the solder particles is preferably 1: 0.06 to 1: 2, more preferably 1: 0.2 to 1: 2, and still more preferably. 1: 1 to 1: 2. The greater the content of the first conductive particles, the easier it is to dispose the first conductive particles between the electrodes, and the conduction reliability is further enhanced. The greater the content of the solder particles, the more difficult the aggregation of the first conductive particles occurs.

  In 100% by weight of the conductive material, the content of the thermoplastic compound or the content of the thermosetting component is preferably 20% by weight or more, more preferably 40% by weight or more, still more preferably 50% by weight or more, preferably Is 99% by weight or less, more preferably 98% by weight or less, still more preferably 90% by weight or less, and particularly preferably 80% by weight or less. From the viewpoint of further enhancing the conduction reliability between the electrodes, it is preferable that the contents of the thermoplastic compound and the thermosetting component are large.

  Examples of the compound that can be cured by heating include an epoxy compound, a (meth) acryl compound, and a phenol compound. Among these, an epoxy compound is preferable from the viewpoint of further improving connection reliability.

  Examples of the thermosetting agent include imidazole curing agents, amine curing agents, phenol curing agents, polythiol curing agents, acid anhydrides, thermal cation curing agents, and thermal radical generators. Among these, an imidazole curing agent, a polythiol curing agent, or an amine curing agent is preferable because the conductive material can be cured more rapidly at a low temperature. Moreover, since a storage stability becomes high when the curable compound curable by heating and the thermosetting agent are mixed, a latent curing agent is preferable. The latent curing agent is preferably a latent imidazole curing agent, a latent polythiol curing agent or a latent amine curing agent. In addition, the said thermosetting agent may be coat | covered with polymeric substances, such as a polyurethane resin or a polyester resin.

  The imidazole curing agent is not particularly limited, and 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2, 4-Diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triazine and 2,4-diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s- Examples include triazine isocyanuric acid adducts.

  The polythiol curing agent is not particularly limited, and examples thereof include trimethylolpropane tris-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate, and dipentaerythritol hexa-3-mercaptopropionate. .

  The amine curing agent is not particularly limited, and hexamethylene diamine, octamethylene diamine, decamethylene diamine, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraspiro [5.5]. Examples include undecane, bis (4-aminocyclohexyl) methane, metaphenylenediamine, and diaminodiphenylsulfone.

  Examples of the thermal cationic curing agent include iodonium-based cationic curing agents, oxonium-based cationic curing agents, and sulfonium-based cationic curing agents. Examples of the iodonium-based cationic curing agent include bis (4-tert-butylphenyl) iodonium hexafluorophosphate. Examples of the oxonium-based cationic curing agent include trimethyloxonium tetrafluoroborate. Examples of the sulfonium-based cationic curing agent include tri-p-tolylsulfonium hexafluorophosphate.

  The thermal radical generator is not particularly limited, and examples thereof include azo compounds and organic peroxides. Examples of the azo compound include azobisisobutyronitrile (AIBN). Examples of the organic peroxide include di-tert-butyl peroxide and methyl ethyl ketone peroxide.

  The content of the thermosetting agent is not particularly limited. The content of the thermosetting agent is preferably 0.01 parts by weight or more, more preferably 1 part by weight or more, preferably 200 parts by weight or less, based on 100 parts by weight of the curable compound that can be cured by heating. The amount is preferably 100 parts by weight or less, more preferably 75 parts by weight or less. When the content of the thermosetting agent is not less than the above lower limit, it is easy to sufficiently cure the conductive material. When the content of the thermosetting agent is not more than the above upper limit, it is difficult for an excess thermosetting agent that did not participate in curing after curing to remain, and the heat resistance of the cured product is further enhanced.

  The binder resin preferably contains a flux. The flux is not particularly limited. As the flux, a flux generally used for soldering or the like can be used. Examples of the flux include zinc chloride, a mixture of zinc chloride and an inorganic halide, a mixture of zinc chloride and an inorganic acid, a molten salt, phosphoric acid, a derivative of phosphoric acid, an organic halide, hydrazine, an organic acid, and pine resin. Is mentioned. As for the said flux, only 1 type may be used and 2 or more types may be used together.

  Examples of the molten salt include ammonium chloride. Examples of the organic acid include lactic acid, citric acid, stearic acid, glutamic acid, and glutaric acid. Examples of the pine resin include activated pine resin and non-activated pine resin. The flux is preferably an organic acid having two or more carboxyl groups, pine resin. The flux may be an organic acid having two or more carboxyl groups, or pine resin. By using an organic acid having two or more carboxyl groups, pine resin, the conduction reliability between the electrodes is further enhanced.

  The rosin is a rosin composed mainly of abietic acid. The flux is preferably rosins, and more preferably abietic acid. By using this preferable flux, the conduction reliability between the electrodes is further enhanced.

  The flux may be dispersed in the conductive material, or may be attached on the surface of the first conductive particles or solder particles.

  In 100% by weight of the conductive material, the content of the flux is 0% by weight or more, preferably 0.5% by weight or more, preferably 30% by weight or less, more preferably 25% by weight or less. The conductive material may not contain flux. When the flux content is not less than the above lower limit and not more than the above upper limit, it becomes more difficult to form an oxide film on the surface of the solder and the electrode, and the oxide film formed on the surface of the solder and the electrode is more effective. Can be removed.

  The conductive material may be, for example, a filler, an extender, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, and a lubricant as necessary. In addition, various additives such as an antistatic agent and a flame retardant may be included.

  The method for dispersing the first conductive particles and the solder particles in the binder resin is not particularly limited, and a conventionally known dispersion method can be used. As a method of dispersing the first conductive particles and the solder particles in the binder resin, for example, after adding the first conductive particles and the solder particles to the binder resin, a planetary mixer or the like The first conductive particles and the solder particles are uniformly dispersed in water or an organic solvent using a homogenizer or the like, and then added to the binder resin, and a planetary mixer, etc. And the method in which the binder resin is diluted with water or an organic solvent, the first conductive particles and the solder particles are added, and the mixture is kneaded and dispersed with a planetary mixer or the like. Is mentioned.

  The conductive material according to the present invention 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 not including the first conductive particles and the solder particles is laminated on the conductive film including the first conductive particles and the solder particles. May be. The conductive paste is preferably an anisotropic conductive paste. The conductive film is preferably an anisotropic conductive film.

(Connection structure)
A connection structure can be obtained by connecting the connection target members using the conductive material described above.

  The connection structure includes a first connection target member, a second connection target member, and a connection portion connecting the first connection target member and the second connection target member, and the connection portion. Is preferably a connection structure formed of the conductive material described above.

  FIG. 1 is a front sectional view schematically showing a connection structure using a conductive material according to the first embodiment of the present invention. The conductive material used here includes solder particles 21B (first conductive particles), solder particles 21 and a binder resin. Before use, the average particle diameter of the solder particles 21 is smaller than the average particle diameter of the solder particles 21B.

  The connection structure 51 </ b> A shown in FIG. 1 is a connection that connects the first connection target member 52, the second connection target member 53, and the first connection target member 52 and the second connection target member 53. 54A. The connecting portion 54A is made of the conductive material. The binder resin preferably includes a thermosetting component, and the connection portion 54A is preferably formed by thermosetting the thermosetting component included in the conductive material.

  FIG. 2 is a front sectional view schematically showing a connection structure using a conductive material according to the second embodiment of the present invention. The conductive material used here includes the first conductive particles 1, the solder particles 21, and the binder resin. Instead of the first conductive particles 1, the first conductive particles 11 or the like may be used.

  The connection structure 51 </ b> B shown in FIG. 2 is a connection that connects the first connection target member 52, the second connection target member 53, and the first connection target member 52 and the second connection target member 53. Part 54B. The connection portion 54B is made of the conductive material. It is preferable that the binder resin includes a thermosetting component, and the connection portion 54B is formed by thermosetting the thermosetting component included in the conductive material.

  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). The first electrode 52a and the second electrode 53a are electrically connected by one or more solder particles 21B or solder particles 21, or one or more first conductive particles 1 or solder particles. 21 is electrically connected. In the connection structure 51A, it is preferable that the connection structure 51A is electrically connected by the solder particles 21B. In the connection structure 51B, it is preferable that the first conductive particles 1 are electrically connected.

  In the connection structure 51A, after the solder particles 21 are melted, they are combined with the solder particles 21B or diffused into the solder particles 21B. Further, the solder particles 21 may exist in a region different from the solder particles 21B. In FIG. 1, the case where the solder particles 21 are melted and then combined with the solder particles 21 </ b> B or diffused in the solder particles 21 </ b> B is shown as solder 21 </ b> A in distinction from the solder particles 21.

  In the connection structure 51B, after the solder particles 21 are melted, they are combined with the solder layer 3B in the first conductive particles 1 or diffused into the solder layer 3B. Further, the solder particles 21 may exist in a region different from the first conductive particles 1. In FIG. 2, the case where the solder particles 21 are melted and bonded to the solder layer 3 </ b> B in the first conductive particles 1 or diffused in the solder layer 3 </ b> B is distinguished from the solder particles 21. , Shown as solder 21A.

The manufacturing method of the connection structure is not particularly limited. As an example of the manufacturing method of the connection structure, the conductive material is disposed between the first connection target member and the second connection target member to obtain a multilayer body, and then the multilayer body is heated. And a method of applying pressure. The solder in the first conductive particles or solder particles is melted by heating and pressurization, and the electrodes are electrically connected by the first conductive particles or solder particles. Furthermore, when the binder resin includes a thermosetting component, the binder resin is thermoset, and the first and second connection target members are connected by the cured binder resin. 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.

  FIG. 3 is an enlarged front sectional view showing a connection portion between the first conductive particles 1 and the first and second electrodes 52a and 53a in the connection structure 51B shown in FIG. As shown in FIG. 3, in the connection structure 51B, after the solder layer 3B in the first conductive particle 1 is melted, the melted solder layer portion 3Ba is in sufficient contact with the first and second electrodes 52a and 53a. To do. That is, by using the first conductive particles 1 whose surface layer is the solder layer 3B, compared to the case where the conductive particles whose surface layer is a metal such as nickel, gold or copper are used, The contact area between the first conductive particles 1 and the first and second electrodes 52a and 53a is increased. For this reason, the conduction | electrical_connection reliability and connection reliability of the connection structure 51B can be improved. When flux is used, the flux generally deactivates gradually due to heating. Further, from the viewpoint of further improving the conduction reliability, it is preferable to bring the second conductive layer 3A into contact with the first electrode 52a, and it is preferable to bring the second conductive layer 3A into contact with the second electrode 53a. .

  The said 1st, 2nd connection object member is not specifically limited. Specifically, the first and second connection target members include electronic components such as semiconductor chips, capacitors, and diodes, and circuit boards such as printed boards, flexible printed boards, glass epoxy boards, and glass boards. Examples include parts. The conductive material is preferably a conductive material used for connecting electronic components. The conductive material is preferably a conductive material used for electrical connection between electrodes. The conductive material is preferably a liquid and is a conductive material that is applied to the upper surface of the connection target member in a liquid 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 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.

(Binder resin)
Thermoplastic compound 1:
In a 3 L separable flask, 219 g of Pripol 1009 (HOOC- (CH ₂ ) ₃₄ —COOH, molecular weight 567, manufactured by Croda Japan Co., Ltd.), 5 g of ethylenediamine (NH ₂ CH ₂ CH ₂ NH ₂ , molecular weight 60), piperazine ( 27 g of C ₄ H ₁₀ N ₂ , molecular weight 86) and 0.8 g of 5% aqueous phosphorous acid solution were added.

  A water separation tube was attached, the temperature was raised to 190 ° C. with stirring under a nitrogen flow, and a polycondensation reaction was performed until the number average molecular weight of the reaction product reached 1400. Thereafter, 83 g of dodecanedioic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was added and stirred at 190 ° C. until the contents became transparent. Thereafter, 358 g of polytetramethylene ether glycol (“PTMG1000” manufactured by Mitsubishi Chemical Corporation, number average molecular weight 1000) and 1 g of Irganox 1098 (manufactured by BASF Japan) were added and stirred until they were even. Thereafter, 0.1 g of antimony trioxide and 0.1 g of monobutylhydroxytin oxide were added, the temperature was raised to 250 ° C., and the mixture was stirred for 30 minutes. The pressure was reduced to 1 mmHg, and the reaction was further performed at 250 ° C. for 4 hours. As a result, a polyamide / polyester block polymer having a number average molecular weight of 28000 and a melting point of 120 ° C. was obtained. This polyamide / polyester block polymer is referred to as thermoplastic compound 1.

Thermosetting compound 1 (epoxy group-containing acrylic resin, "Blemmer CP-30" manufactured by Mitsubishi Chemical Corporation)
Thermosetting compound 2 (bisphenol A type epoxy compound, “YL980” manufactured by Mitsubishi Chemical Corporation)
Thermosetting compound 3 (resorcinol type epoxy compound, “EX-201” manufactured by Nagase ChemteX Corporation)
Thermosetting compound 4 (epoxy compound, “EXA-4850-150” manufactured by DIC)
Thermosetting compound 5 (phenoxy resin, “PKHC” manufactured by Inchem, weight average molecular weight 43000)
Thermosetting compound 6 (epoxy compound, “EPICLON HP-4032D” manufactured by DIC Corporation)
Thermosetting agent A (imidazole compound, “2P-4MZ” manufactured by Shikoku Kasei Kogyo Co., Ltd.)
Thermosetting agent B (amine adduct of imidazole, “PN-23” manufactured by Ajinomoto Fine Techno Co.)
Thermal cation generator 1 (compound represented by the following formula (11), compound that releases inorganic acid ion containing phosphorus atom by heating)

  Thermal cation generator 2 (compound represented by the following formula (12), compound that releases inorganic acid ion containing antimony atom by heating)

  Thermal cation generator 3 (compound represented by the following formula (13), a compound that releases an organic acid ion containing a boron atom by heating)

Curing accelerator A (2-ethyl-4-methylimidazole)
Adhesion imparting agent: “KBE-403” manufactured by Shin-Etsu Chemical Co., Ltd.
Flux: “Glutaric acid” manufactured by Wako Pure Chemical Industries, Ltd.

(First conductive particles and solder particles)
First conductive particles 1 (resin core solder-coated particles, prepared by the following procedure)
Divinylbenzene resin particles (“Micropearl SP-210” manufactured by Sekisui Chemical Co., Ltd., average particle diameter 10 μm, softening point 330 ° C., 10% K value (23 ° C.) 3.8 GPa) are electroless nickel plated, A base nickel plating layer having a thickness of 0.1 μm was formed on the surface. Next, the resin particles on which the base nickel plating layer was formed were subjected to electrolytic copper plating to form a 1 μm thick copper layer. Further, electrolytic plating was performed using an electrolytic plating solution containing tin and bismuth to form a 2 μm thick solder layer. In this way, a 1 μm thick copper layer is formed on the surface of the resin particles, and a 2 μm thick solder layer (tin: bismuth = 43 wt%: 57 wt%) is formed on the surface of the copper layer. Conductive particles (average particle size 16 μm, CV value 20%, resin core solder-coated particles) were prepared.
First conductive particles 2 (resin core solder-coated particles, prepared by the following procedure)
Divinylbenzene resin particles (“Micropearl SP-210” manufactured by Sekisui Chemical Co., Ltd., average particle size 5 μm, softening point 330 ° C., 10% K value (23 ° C.) 3.8 GPa) are electroless nickel plated, A base nickel plating layer having a thickness of 0.1 μm was formed on the surface. Next, the resin particles on which the base nickel plating layer was formed were subjected to electrolytic copper plating to form a 1 μm thick copper layer. Further, electrolytic plating was performed using an electrolytic plating solution containing tin and bismuth to form a 2 μm thick solder layer. In this way, a 1 μm thick copper layer is formed on the surface of the resin particles, and a 2 μm thick solder layer (tin: bismuth = 43 wt%: 57 wt%) is formed on the surface of the copper layer. Conductive particles (average particle diameter 11 μm, CV value 20%, resin core solder-coated particles) were prepared.
First conductive particles 3: SnBi solder particles (tin: bismuth = 43 wt%: 57 wt%, average particle diameter: 15 μm)
First conductive particles 4: SnBi solder particles (tin: bismuth = 43 wt%: 57 wt%, average particle diameter 13 μm)
First conductive particles 5: SnBi solder particles (tin: bismuth = 43 wt%: 57 wt%, average particle diameter 9 μm)
Solder particles A: SnBi solder particles (tin: bismuth = 43 wt%: 57 wt%, average particle diameter 3 μm)
Solder particles B: SnBi solder particles (tin: bismuth = 43 wt%: 57 wt%, average particle diameter 10 μm)
Solder particles C: SnBi solder particles (tin: bismuth = 43 wt%: 57 wt%, average particle diameter 5 μm)

(Examples 1 to 53 and Comparative Examples 1 to 10)
The components shown in Tables 1 to 3 below were blended in the blending amounts shown in Tables 1 to 3 to obtain anisotropic conductive pastes.

  In addition, the components shown in Tables 4 and 5 below were blended in the blending amounts shown in Tables 4 and 5 below, and further toluene as a solvent was blended so that the solid content was 35% by weight. The resulting composition was obtained by stirring at 2000 rpm for 5 minutes. After coating the obtained composition on the polyethylene terephthalate film subjected to the release treatment, the solvent was removed by vacuum drying at 80 ° C. for 15 minutes to obtain an anisotropic conductive film having a thickness of 50 μm.

(Evaluation)
(1) Aggregation state The obtained anisotropic conductive paste was stored at 25 ° C. for 72 hours. After storage, it was evaluated whether or not the first conductive particles aggregated in the anisotropic conductive paste were settled. Moreover, the composition prepared when obtaining an anisotropic conductive film was stored at 25 degreeC for 72 hours. The anisotropic conductive films of Examples and Comparative Examples were produced in the same manner except that the composition after storage was used. It was evaluated whether or not the aggregated first conductive particles in the obtained anisotropic conductive film were settled. The aggregation state was determined according to the following criteria.

  In addition, the said composition may be stored in the step which obtains an anisotropic conductive film. By suppressing sedimentation of the first conductive particles in the composition, an anisotropic conductive film in which aggregation of the first conductive particles is suppressed can be obtained.

[Judgment criteria for aggregation state]
○: Aggregated first conductive particles are not settled Δ: Aggregated first conductive particles are slightly settled ×: Many aggregated first conductive particles are settled

(2) Production of first connection structure (L / S = 50 μm / 50 μm) Glass epoxy substrate (FR-4 substrate) having a copper electrode pattern (copper electrode thickness 10 μm) with L / S of 50 μm / 50 μm on the upper surface Prepared. Moreover, the flexible printed circuit board which has a copper electrode pattern (copper electrode thickness 10 micrometers) whose L / S is 50 micrometers / 50 micrometers on the lower surface was prepared.

  The overlapping area of the glass epoxy substrate and the flexible printed circuit board was 1.5 cm × 4 mm, and the number of connected electrodes was 75 pairs.

  On the upper surface of the glass epoxy substrate, the anisotropic conductive paste immediately after preparation was applied to a thickness of 50 μm to form an anisotropic conductive material layer. Next, the flexible printed circuit board was laminated on the upper surface of the anisotropic conductive material layer so that the electrodes face each other. Then, while adjusting the temperature of the head so that the temperature of the anisotropic conductive material layer is 185 ° C., a pressure heating head is placed on the upper surface of the semiconductor chip and a pressure of 2.0 MPa is applied to melt the solder. And the anisotropic conductive material layer was hardened at 185 degreeC, and the 1st connection structure using an anisotropic conductive paste was obtained.

  Further, a first anisotropic conductive film was used in the same manner except that the anisotropic conductive film immediately after fabrication was laminated on the upper surface of the glass epoxy substrate to form an anisotropic conductive material layer. A connection structure was obtained.

(3) Production of second connection structure (L / S = 75 μm / 75 μm) Glass epoxy substrate (FR-4 substrate) having a copper electrode pattern (copper electrode thickness 10 μm) having L / S of 75 μm / 75 μm on the upper surface Prepared. Moreover, the flexible printed circuit board which has a copper electrode pattern (copper electrode thickness 10 micrometers) whose L / S is 75 micrometers / 75 micrometers on the lower surface was prepared.

  A second connection structure was obtained in the same manner as the production of the first connection structure except that the glass epoxy substrate and the flexible printed circuit board having different L / S were used.

(4) Production of third connection structure (L / S = 100 μm / 100 μm) Glass epoxy substrate (FR-4 substrate) having a copper electrode pattern (copper electrode thickness 10 μm) having L / S of 100 μm / 100 μm on the upper surface Prepared. Moreover, the flexible printed circuit board which has a copper electrode pattern (copper electrode thickness 10 micrometers) with L / S of 100 micrometers / 100 micrometers on the lower surface was prepared.

  A third connection structure was obtained in the same manner as the production of the first connection structure except that the glass epoxy substrate and the flexible printed circuit board having different L / S were used.

(5) Conduction reliability between upper and lower electrodes In the obtained first, second and third connection structures (n = 15), the connection resistance between the upper and lower electrodes was measured by the four-terminal method, respectively. . The average value of connection resistance 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 conduction reliability was determined according to the following criteria.

[Judgment criteria for conduction reliability]
○○: Average value of connection resistance is 8.0Ω or less ○: Average value of connection resistance exceeds 8.0Ω and 10.0Ω or less △: Average value of connection resistance exceeds 10.0Ω and 15.0Ω or less × Average connection resistance exceeds 15.0Ω

(6) Insulation reliability between adjacent electrodes In the obtained first, second and third connection structures (n = 15), 15 V was applied between the adjacent electrodes, and the resistance value was 25 locations. Measured with Insulation reliability was judged according to the following criteria.

[Criteria for insulation reliability]
○: 85 ℃, 85% RH in the insulation resistance 1.0 × 10 ⁷ Ω or more 500 hours holding △: 85 ℃, 85% RH in the insulation resistance 1.0 × 10 ⁷ Ω or more 250 or more hours, 500 Retained for less than time x: Retained at an insulation resistance value of 1.0 × 10 ⁷ Ω or higher at 85 ° C. and 85% RH for less than 250 hours

  The results are shown in Tables 1 to 5 below.

  In all the examples, in the obtained first, second, and third connection structures, the copper layer was in contact with the electrode.

DESCRIPTION OF SYMBOLS 1 ... 1st electroconductive particle 2 ... Base particle 3 ... Conductive layer 3A ... 2nd electroconductive layer 3B ... Solder layer 3Ba ... Molten solder layer part 11 ... 1st electroconductive particle 12 ... Solder layer 21 ... Solder Particle 21A ... solder 21B ... solder particle (first conductive particle)
51A, 51B ... Connection structure 52 ... First connection object member 52a ... First electrode 53 ... Second connection object member 53a ... Second electrode 54A, 54B ... Connection part

Claims (14)

First conductive particles having solder on a conductive surface;
Solder particles having an average particle size smaller than that of the first conductive particles;
A conductive material containing a binder resin.   2. The conductive material according to claim 1, wherein a ratio of an average particle diameter of the solder particles to an average particle diameter of the first conductive particles is 0.1 or more and 0.7 or less.   The conductive material according to claim 1 or 2, wherein an average particle diameter of the first conductive particles is 1 µm or more and 20 µm or less.   The conductive material according to any one of claims 1 to 3, wherein a CV value of a particle diameter of the first conductive particles is 20% or less.   The conductive material according to claim 1, wherein the first conductive particles are solder particles.   The conductive material according to any one of claims 1 to 4, wherein the first conductive particles include base particles and a solder layer disposed on a surface of the base particles. First conductive particles having solder on a conductive surface, solder particles having an average particle diameter smaller than that of the first conductive particles, and a binder resin are mixed.
A method for producing a conductive material, wherein a conductive material including the first conductive particles, the solder particles, and the binder resin is obtained.   The method for producing a conductive material according to claim 7, wherein a ratio of an average particle diameter of the solder particles to an average particle diameter of the first conductive particles is 0.1 or more and 0.7 or less.   The manufacturing method of the electrically-conductive material of Claim 7 or 8 whose average particle diameter of a said 1st electroconductive particle is 1 micrometer or more and 20 micrometers or less.   The manufacturing method of the electrically-conductive material of any one of Claims 7-9 whose CV value of the particle diameter of a said 1st electroconductive particle is 20% or less.   The manufacturing method of the electrically-conductive material of any one of Claims 7-10 whose said 1st electroconductive particle is a solder particle.   The manufacturing method of the electrically-conductive material of any one of Claims 7-11 with which a said 1st electroconductive particle is provided with a base material particle and the solder layer arrange | positioned on the surface of the said base material particle. 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 connection portion connecting the first connection target member and the second connection target member;
The connecting portion is formed of the conductive material according to any one of claims 1 to 6,
The connection structure in which the first electrode and the second electrode are electrically connected by the first conductive particles or the solder particles contained in the conductive material. 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 connection portion connecting the first connection target member and the second connection target member;
The connection portion is formed of a conductive material obtained by the method for manufacturing a conductive material according to any one of claims 7 to 12,
The connection structure in which the first electrode and the second electrode are electrically connected by the first conductive particles or the solder particles contained in the conductive material.

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