JP6097162B2 - Conductive particles and solder joint materials - Google Patents

Description

  The present invention relates to conductive particles dispersed in solder and used as a solder paste or a solder sheet. The present invention also relates to a solder joint material that includes the conductive particles and solder and is a solder paste or a solder sheet.

  In a non-insulated semiconductor device which is one of power semiconductor devices used for an inverter or the like, a member for fixing a semiconductor element is also one of electrodes of the semiconductor device. For example, in a semiconductor device in which a power transistor is mounted on a fixing member using an Sn—Pb soldering material, the fixing member (base material) serves as a collector electrode portion of the power transistor. In this collector electrode portion, a current of several amperes or more flows when the semiconductor device is operated, and the transistor chip generates heat. In order to avoid destabilization of characteristics and a decrease in service life due to this heat generation, it is necessary to sufficiently ensure the heat dissipation and heat resistance of the soldered portion. In order to ensure sufficient heat dissipation and heat resistance of the soldered portion, it is necessary to use a material having excellent heat dissipation.

  Also in an insulated semiconductor device, in order to operate a semiconductor element safely and stably, it is necessary to efficiently dissipate heat generated during operation of the semiconductor device to the outside of the semiconductor device. In this case, it is also necessary to ensure the bonding reliability of the soldered portion.

  As a bonding material having high heat dissipation and high bonding reliability, the following Patent Document 1 discloses a bonding material that has a shape in a solidified state and is used to connect members to be electrically bonded. ing. In this bonding material, spherical or irregular heat-resistant resin powder having elasticity is evenly dispersed inside the solder.

  Patent Document 2 below discloses a bonding material in which an additive having a constant particle size is dispersed on the upper surface of a flat solder material. Examples of the additive include an additive having a melting point higher than that of the solder material, an additive having a good thermal conductivity, an additive that is an insulator, and an additive in which the surface of the insulator is coated with a conductive metal. .

JP-A-11-254185 Japanese Patent Laid-Open No. 06-232188

  In the conventional bonding materials as described in Patent Documents 1 and 2, there may be a variation in the interval between the members bonded by the bonding material. That is, the thickness of the joint formed by the joining material may vary. Therefore, there is a problem that reliability of electronic parts such as a semiconductor device using a conventional bonding material is lowered.

  The object of the present invention is to improve the reliability and heat dissipation of the first and second members to be joined after joining the first and second members to be joined, and further to the first and second members to be joined. It is an object of the present invention to provide conductive particles capable of obtaining a solder paste or a solder sheet capable of controlling the interval therebetween with high accuracy. Another object of the present invention is to provide a solder joint material that includes the conductive particles and solder and is a solder paste or a solder sheet.

  According to a wide aspect of the present invention, conductive particles dispersed in solder and used as a solder paste or a solder sheet, the substrate particles, and a conductive layer disposed on the surface of the substrate particles, There are provided conductive particles, wherein the substrate particles are resin particles or organic-inorganic hybrid particles, the specific gravity is 1.5 or more and 4.0 or less, and the particle diameter is 8 μm or more and 200 μm or less. The

  On the specific situation with the electroconductive particle which concerns on this invention, the said conductive layer has a copper layer.

  On the specific situation with the electroconductive particle which concerns on this invention, the said electroconductive particle is on the outer surface of the said base material particle, the copper layer arrange | positioned on the surface of the said base material particle, and the said copper layer. A second conductive layer disposed, or a base layer and a copper layer disposed on the surface of the base particle, and the outer surface of the copper layer is subjected to a rust prevention treatment. Has been.

  On the specific situation with the electroconductive particle which concerns on this invention, the said electroconductive particle is on the outer surface of the said base material particle, the copper layer arrange | positioned on the surface of the said base material particle, and the said copper layer. And a second conductive layer disposed.

  On the specific situation with the electroconductive particle which concerns on this invention, a said 2nd conductive layer contains nickel, gold | metal | money, silver, or tin.

  In a specific aspect of the conductive particle according to the present invention, the base particle and the copper layer disposed on the surface of the base particle are provided, and the outer surface of the copper layer is subjected to a rust prevention treatment. ing.

  On the specific situation with the electroconductive particle which concerns on this invention, the said base material particle is the said resin particle.

  On the specific situation with the electroconductive particle which concerns on this invention, the said base material particle is the said organic-inorganic hybrid particle.

  The conductive particles according to the present invention are preferably dispersed in solder and used as a solder sheet.

  According to a wide aspect of the present invention, there is provided a solder joint material that includes the above-described conductive particles and solder and is a solder paste or a solder sheet.

  In the electroconductive particle which concerns on this invention, the electroconductive layer is arrange | positioned on the surface of base material particle, The said base material particle is a resin particle or an organic inorganic hybrid particle, and specific gravity is 1.5 or more and 4.0. Since the particle diameter is 8 μm or more and 200 μm or less, when the conductive particles according to the present invention are dispersed in solder and used as a solder paste or solder sheet, they are joined by the solder paste or solder sheet. The joining reliability and heat dissipation of the made 1st, 2nd joining object member can be improved. Furthermore, the space | interval between the said 1st, 2nd joining object member after joining can be controlled with high precision.

FIG. 1 is a cross-sectional view schematically showing conductive particles according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing conductive particles according to the second embodiment of the present invention. FIG. 3 is a cross-sectional view schematically showing conductive particles according to the third embodiment of the present invention. FIG. 4 is a cross-sectional view schematically showing a solder sheet using the conductive particles shown in FIG. FIG. 5 is a cross-sectional view schematically showing a joint structure using the solder sheet shown in FIG.

  Hereinafter, the present invention will be described in detail.

  The conductive particles according to the present invention are dispersed in solder and used as a solder paste or a solder sheet. The conductive particles according to the present invention are different from the conductive particles used by being dispersed in a binder resin (such as a thermosetting resin or a thermoplastic resin) other than solder. The solder paste or solder sheet is a solder joint material. The conductive particles according to the present invention are used for solder joint materials and are conductive particles for solder joint materials. The electroconductive particle which concerns on this invention is equipped with a base material particle and the electroconductive layer arrange | positioned on the surface of this base material particle. The base particles are resin particles or organic-inorganic hybrid particles. The specific gravity of the conductive particles according to the present invention is 1.5 or more and 4.0 or less. The particle diameter of the conductive particles according to the present invention is 8 μm or more and 200 μm or less.

  When such conductive particles are dispersed in solder and used as a solder paste or a solder sheet, and the first and second joining target members are joined by the solder paste or the solder sheet, the solder and the conductive particles are included. The joining reliability and heat dissipation between the joined portion and the first and second joining target members can be improved. The joint is formed from a solder paste or a solder sheet. Furthermore, the space | interval between the 1st, 2nd joining object members can be controlled with high precision by the electroconductive particle arrange | positioned between the 1st, 2nd joining object members. By controlling the interval between the first and second members to be joined with high accuracy, it is possible to suppress the thickness of the joint portion from being partially reduced, and as a result, the heat dissipation of the joint portion is partially reduced. It can also be suppressed.

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

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

  As shown in FIG. 1, the conductive particles 21 include resin particles 22 and a conductive layer 23 disposed on the surface 22 a of the resin particles 22. The conductive layer 23 is laminated on the surface 22 a of the resin particle 22. The conductive layer 23 covers the surface 22 a of the resin particle 22. The conductive layer 23 is a single layer. The conductive layer 23 is preferably a copper layer.

  In FIG. 2, the electroconductive particle which concerns on the 2nd Embodiment of this invention is typically shown with sectional drawing.

  2 includes resin particles 22 and a conductive layer 32 disposed on the surface 22a of the resin particles 22. The conductive particles 31 illustrated in FIG. The conductive layer 32 is laminated on the surface 22 a of the resin particle 22. The conductive layer 32 covers the surface 22 a of the resin particle 22. The conductive layer 32 is a multilayer and has a two-layer structure. The conductive layer 32 includes a first conductive layer 32A that is an inner layer and a second conductive layer 32B that is an outer layer. The conductive particles 31 include a resin particle 22, a first conductive layer 32A disposed on the surface 22a of the resin particle 22, and a second conductive layer disposed on the outer surface of the first conductive layer 32A. 32B. The second conductive layer 32B, which is the outer layer, is disposed on the outer surface of the first conductive layer 32A, which is the inner layer, and covers the outer surface of the first conductive layer 32A. The first conductive layer 32A is preferably a copper layer. The second conductive layer 32B preferably contains nickel, gold, silver, or tin. In the conductive particles 31, organic / inorganic hybrid particles may be used instead of the resin particles 22.

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

  As shown in FIG. 1, the conductive particles 41 include organic-inorganic hybrid particles 42 and a conductive layer 23 disposed on the surface 42 a of the organic-inorganic hybrid particles 42. The organic-inorganic hybrid particle 42 has an organic core 42A and an inorganic shell 42B disposed on the surface of the organic core 42A. The conductive layer 23 is laminated on the surface 42a of the organic-inorganic hybrid particle 42 and on the outer surface of the inorganic shell 42B. The conductive layer 23 covers the surface 42a of the organic-inorganic hybrid particle 42 and the outer surface of the inorganic shell 42B. The conductive layer 23 is a single layer. The conductive layer 23 is preferably a copper layer.

  The electroconductive particle which concerns on this invention is electroconductive particle which has a base material particle and the conductive layer arrange | positioned on the surface of this base material particle. From the viewpoint of increasing the flexibility of the joint, increasing the flexibility of the conductive particles, allowing the conductive particles to be appropriately compressed and deformed, and further improving the impact resistance of the bonded structure, the conductive particles described above. Comprises substrate particles, and the substrate particles are the resin particles or the organic-inorganic hybrid particles.

  The base particles are resin particles or organic-inorganic hybrid particles. The substrate particles are preferably the resin particles, and more preferably the organic-inorganic hybrid 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 still higher.

  Various organic materials are suitably used as the resin for forming the resin particles. 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, silicone resin, Polysulfone, polyphenylene oxide, polyacetal, polyimide, polyamideimide, poly Chromatography ether ether ketone, polyether sulfone and, polymers and the like obtained by a variety of polymerizable monomer is polymerized with one or more having an ethylenically unsaturated group is used. By polymerizing one or more of various polymerizable monomers having an ethylenically unsaturated group, it is possible to design and synthesize resin particles having any compression property suitable for bonding.

  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 Child-containing (meth) acrylates; Nitrile-containing monomers such as (meth) acrylonitrile; Vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, and propyl vinyl ether; Vinyl acetates such as vinyl acetate, vinyl butyrate, vinyl laurate, and 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.

  Regarding the composition of the resin particles, tetrafunctional or trifunctional (meth) acrylate, a copolymer of divinylbenzene, and a silicone resin are suitable because of good heat resistance.

  When the base material particles are inorganic particles or organic-inorganic hybrid particles excluding metal particles, inorganic materials for forming the base material particles include silica, alumina, barium titanate, zirconia, carbon black, titanium oxide, Examples thereof include boron nitride, aluminum nitride, zinc oxide and diamond. 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.

  The organic-inorganic hybrid particles are preferably core-shell type organic-inorganic hybrid particles having a core and a shell disposed on the surface of the core. The core is preferably an organic core. The shell is preferably an inorganic shell. From the viewpoint of effectively reducing the connection resistance between the electrodes, the base material particles are preferably organic-inorganic hybrid particles having an organic core and an inorganic shell disposed on the surface of the organic core.

  Examples of the material for forming the organic core include the resin for forming the resin particles described above.

  Examples of the material for forming the inorganic shell include inorganic substances for forming the above-described base material particles. The material for forming the inorganic shell is preferably silica. The inorganic shell is preferably formed on the surface of the core by forming a metal alkoxide into a shell by a sol-gel method and then sintering the shell. The metal alkoxide is preferably a silane alkoxide. The inorganic shell is preferably formed of a silane alkoxide.

  Examples of the metal for forming the conductive layer include gold, silver, palladium, copper, platinum, zinc, iron, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, germanium, cadmium, Examples thereof include bismuth, thallium, tin-lead alloy, tin-copper alloy, tin-silver alloy, and tin-lead-silver alloy. Further, tin-doped indium oxide (ITO) may be used as the metal. As for the said metal, only 1 type may be used, 2 or more types may be used together, and an alloy may be sufficient as it.

  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.

  The particle diameter of the conductive particles is 8 μm or more and 200 μm or less. The particle diameter of the conductive particles is preferably 10 μm or more, preferably 150 μm or less, more preferably 100 μm or less. The particle diameter of the conductive particles may be 60 μm or less. When the particle diameter of the conductive particles is not less than the above lower limit and not more than the above upper limit, the joining reliability of the joining target members is further increased, and the variation in the interval between the joining target members is further reduced. Further, when the particle diameter of the conductive particles is equal to or more than the lower limit, the thickness of the joint portion disposed between the first and second members to be joined can be further increased, and the heat dissipation by the joint portion and Bonding reliability can be further increased. When the particle diameter of the conductive particles is less than or equal to the above upper limit, the distance between the electrodes can be further reduced, and the bonded structure can be reduced in size and thickness. The particle diameter of the conductive particles indicates the diameter when the conductive particles are true spherical, and indicates the maximum diameter when the conductive particles are not true spherical. As for the particle diameters of the resin particles and the organic core, when the resin particles and the organic core are true spheres, the diameter is shown. When the resin particles and the organic core are not true spheres, the diameter is maximum. Indicates the diameter.

  The conductive particles have a specific gravity of 1.5 or more and 4.0 or less. The specific gravity of the conductive particles is preferably 2.0, preferably 3.0. When the specific gravity of the conductive particles is not less than the above lower limit and not more than the above upper limit, the joining reliability of the joining target members is further increased, and the variation in the interval between the joining target members is further reduced.

  The thickness of the entire conductive layer is preferably 5 nm or more, more preferably 10 nm or more, still more preferably 50 nm or more, preferably 5000 nm or less, more preferably 1000 nm or less, still more preferably 500 nm or less, and particularly preferably 300 nm or less. When the thickness of the entire conductive layer is at least the above lower limit, the conductivity of the conductive particles can be sufficiently increased, and excessive cracking of the conductive layer can be suppressed. As a result of suppressing the cracking of the conductive layer, the thickness of the joint can be made even more uniform, so that the heat dissipation of the joint can be partially prevented from being lowered. When the thickness of the entire conductive layer is not more than the above upper limit, the stress at the interface due to the difference in coefficient of thermal expansion between the base particle and the conductive layer is relaxed, and the conductive layer is difficult to peel from the base particle.

  The ratio of the particle diameter of the substrate particles to the thickness of the entire conductive layer (particle diameter of the substrate particles / total thickness of the conductive layer) is preferably 10 or more, more preferably 30 or more, preferably 3000 or less, more preferably. 500 or less. The thickness of the whole conductive layer is the average thickness of the whole conductive layer.

  When the conductive layer is formed of a plurality of layers, the thickness of the outermost conductive layer and the second conductive layer is preferably 10 nm or more, more preferably 50 nm or more, preferably 500 nm or less, more preferably Is 100 nm or less. When the thickness of the conductive layer that is the outermost layer and the thickness of the second conductive layer is not less than the lower limit and not more than the upper limit, the coating with the conductive layer that is the outermost layer and the second conductive layer becomes uniform, and corrosion resistance The nature becomes sufficiently high.

  The conductive layer preferably has a copper layer. The first conductive layer is preferably a copper layer. It is preferable that the said electroconductive particle is equipped with a base particle and the copper layer arrange | positioned on the surface of a base particle. The copper layer is preferably in contact with the substrate particles. When the conductive layer has a copper layer, the heat dissipation is further improved. From the viewpoint of enhancing the corrosion resistance, it is preferable that the outer surface of the copper layer is subjected to rust prevention treatment.

  From the viewpoint of further improving the heat dissipation, the conductive particles include the base particles, the copper layer disposed on the surface of the base particles, and the second conductive disposed on the outer surface of the copper layer. Or the conductive particles are provided with base particles and a copper layer disposed on the surface of the base particles, and the outer surface of the copper layer is subjected to rust prevention treatment. Is preferred. The conductive layer may include substrate particles, a copper layer disposed on the surface of the substrate particles, and a second conductive layer disposed on the outer surface of the copper layer. The conductive particles preferably include base particles and a copper layer disposed on the surface of the base particles, and the outer surface of the copper layer is rust-proofed. From the viewpoint of further improving the conductivity, heat dissipation, and corrosion resistance, the second conductive layer preferably contains nickel, gold, silver, or tin.

  Examples of the material used for the rust prevention treatment include benzotriazole compounds. Examples of the benzotriazole compounds include benzotriazole, 1- [N, N-di (2-ethylhexyl) amino] methyl-1H-benzotriazole and 1- [N, N-di (2-ethylhexyl) amino] methyl-1H. -Methylbenzotriazole and the like. Among them, since corrosion resistance is further enhanced and a further excellent rust prevention effect is obtained, it is preferable to carry out a rust prevention treatment using a benttriazole compound, and it is more preferred to carry out a rust prevention treatment using benzotriazole. .

  The outer surface of the conductive layer is preferably a copper layer or a second conductive layer containing nickel, gold, silver or tin. More preferably, the outer surface of the conductive layer is a second conductive layer containing nickel, gold, silver or tin. When the outer surface of the conductive layer contains copper, nickel, gold, silver, or tin, conductivity and heat dissipation are further improved.

  The surface of the conductive particles and the outer surface of the conductive layer are preferably not melted at 450 ° C., and more preferably not melted at 400 ° C. It is possible to suppress deformation of the conductive particles when the solder is melted. For this reason, the space | interval between the 1st, 2nd joining object member can be controlled with higher precision after joining. Furthermore, since the thickness of the joint portion can be made even more uniform, it is possible to suppress a partial decrease in heat dissipation of the joint portion.

  It is preferable that the conductive layer does not melt when the members to be joined are joined. It is preferable that the conductive layer does not melt when the solder is melted. The melting point of the conductive layer is preferably higher than the melting point of the solder. The melting point of the conductive layer is preferably 5 ° C. or more higher than the melting point of the solder, more preferably 10 ° C. or more, further preferably 20 ° C. or more, and particularly preferably 50 ° C. or more.

The compression modulus (5% K value) when the conductive particles are compressed by 5% is preferably 1000 mN / mm ² or more, more preferably 3000 mN / mm ² or more, preferably 20000 mN / mm ² or less, more preferably 18000 mN. / Mm ² or less. In order to better control the structure in which the conductive particles are embedded and to further reduce the connection resistance between the electrodes, the 5% K value of the conductive particles is preferably not less than the above lower limit and not more than the above upper limit.

  The compression elastic modulus (5% K value) of the conductive particles can be measured as follows.

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

5% K value (N / mm ² ) = (3/2 ^1/2 ) · F · S ⁻³ / ² · R ^−1/2
F: Load value when the conductive particles are compressively deformed by 5% (N)
S: Compression displacement (mm) when conductive particles are 5% compressively deformed
R: radius of conductive particles (mm)

  The compression elastic modulus universally and quantitatively represents the hardness of the conductive particles. By using the compression elastic modulus, the hardness of the conductive particles can be expressed quantitatively and uniquely.

  In 100% by weight of the solder paste or 100% by weight of the solder sheet, the content of the conductive particles is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, and further preferably 0.5% by weight. % Or more, particularly preferably 1% by weight or more, preferably 40% by weight or less, more preferably 30% by weight or less, and still more preferably 15% by weight or less. When the content of the conductive particles is equal to or more than the lower limit, the conductive particles can be sufficiently present between the first and second members to be joined, and the first and second conductive particles are used. It can further suppress that the space | interval between joining object members becomes partially narrow. For this reason, it can also suppress that the heat dissipation of a junction part falls partially.

  The solder paste and the solder sheet may contain a binder other than solder. The binder used for the solder paste and the solder sheet is not particularly limited. The binder is preferably lost when the solder is melted.

  Specific examples of the binder include aliphatic solvents, ketone solvents, aromatic solvents, ester solvents, ether solvents, alcohol solvents, paraffin solvents, petroleum solvents, and the like.

  Examples of the aliphatic solvent include cyclohexane, methylcyclohexane, and ethylcyclohexane. Examples of the ketone solvent include acetone and methyl ethyl ketone. Examples of the aromatic solvent include toluene and xylene. Examples of the ester solvent include ethyl acetate, butyl acetate and isopropyl acetate. Examples of the ether solvent include tetrahydrofuran (THF) and dioxane. Examples of the alcohol solvent include ethanol and butanol. Examples of the paraffinic solvent include paraffin oil and naphthenic oil. Examples of the petroleum solvent include mineral terpenes and naphtha.

  The conductive particles according to the present invention are dispersed in solder and used as a solder paste or a solder sheet. The conductive particles according to the present invention may be dispersed in solder and used as a solder paste. The conductive particles according to the present invention may be dispersed in solder and used as a solder sheet.

  The solder joint material according to the present invention includes the above conductive particles and solder, and is a solder paste or a solder sheet.

  Since the handleability is excellent, the conductive particles are preferably dispersed in the solder and used as a solder sheet. Since it is excellent in handleability, the solder joint material according to the present invention is preferably a solder sheet.

  FIG. 4 is a cross-sectional view schematically showing a solder sheet using the conductive particles 21 shown in FIG.

  A solder sheet 11 shown in FIG. 4 includes solder 16 and conductive particles 21 dispersed in the solder 16. A plurality of conductive particles 21 are dispersed in the solder 16.

  The solder contained in the solder sheet is preferably a filler material having a liquidus of 450 ° C. or lower based on JIS Z3001: Welding terms. Examples of the solder composition include metal compositions containing zinc, gold, lead, copper, tin, bismuth, indium and the like. 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 preferably does not contain lead, and is preferably a solder containing tin and indium or a solder containing tin and bismuth.

  The melting point of the solder is preferably 450 ° C. or lower, more preferably 300 ° C. or lower, still more preferably 200 ° C. or lower, and particularly preferably 160 ° C. or lower.

  In 100% by weight of the metal contained in the solder, the content of tin is preferably 30% by weight or more, more preferably 40% by weight or more, still more preferably 70% by weight or more, and particularly preferably 90% by weight or more. When the content of tin in the solder is equal to or higher than the lower limit, the bonding reliability between the solder and the member to be bonded 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.

  The solder paste can be obtained by dispersing conductive particles in molten solder. The solder sheet can be obtained, for example, by dispersing conductive particles in molten solder and then solidifying the solder.

  The temperature for melting the solder is preferably lower than the temperature for melting the surfaces of the conductive particles and the outer surface of the conductive layer. The temperature for melting the solder is preferably 5 ° C. or more, more preferably 10 ° C. or more, lower than the temperature at which the surface of the conductive particles melts. When the temperature at which the solder is melted and the temperature at which the surface of the conductive particles melts satisfy the above relationship, the conductive particles can be prevented from being deformed when the solder is melted. For this reason, the space | interval between the 1st, 2nd joining object member can be controlled with higher precision after joining. Furthermore, since the thickness of the joint portion can be made even more uniform, it is possible to suppress a partial decrease in heat dissipation of the joint portion.

  FIG. 5 is a cross-sectional view schematically showing a joined structure using the solder sheet 11 shown in FIG.

  The joining structure 1 shown in FIG. 5 joins the first joining target member 2, the second joining target members 3, 4, and the first joining target member 2 and the second joining target members 3, 4. Connecting portions 5 and 6. The joint portions 5 and 6 are formed using a solder sheet 11 including solder 16 and conductive particles 21. Specifically, the joint portions 5 and 6 are formed by melting the solder 16 in the solder sheet 11 and then solidifying the solder 16.

  The joining portion 5 and the second joining target member 3 are arranged on the first surface 2a (one surface) side of the first joining target member 2. The joining portion 5 joins the first joining target member 2 and the second joining target member 3.

  The joining portion 6 and the second joining target member 4 are disposed on the second surface 2b (the other surface) side opposite to the first surface 2a of the first joining target member 2. The joining portion 6 joins the first joining target member 2 and the second joining target member 4.

  Conductive particles 21 are disposed between the first member 2 and the second members 3, 4, respectively. The joints 5 and 6 include solder 16. A solder 16 is disposed between the first joining target member 2 and the second joining target members 3 and 4. The first joining target member 2 and the second joining target members 3 and 4 are joined by the solder 16.

  A heat sink 7 is arranged on the surface opposite to the joint portion 5 side of the second joining target member 3. A heat sink 8 is disposed on the surface of the second joining target member 4 on the side opposite to the joining portion 6 side. Therefore, the bonding structure 1 includes the heat sink 7, the second bonding target member 3, the bonding portion 5, the first bonding target member 2, the bonding portion 6, the second bonding target member 4, and the heat sink 8 stacked in this order. It has the part which was made.

  Examples of the first joining target member 2 include power semiconductor elements used for inverters, converters, and the like. In the joining structure 1 including the first joining target member 2, a large amount of heat is likely to be generated in the first joining target member 2 when the joining structure 1 is used. Therefore, it is necessary to efficiently dissipate the heat generated from the first joining target member 2 to the heat sinks 7 and 8. For this reason, high heat dissipation is calculated | required by the junction parts 5 and 6 arrange | positioned between the 1st joining object member 2 and the heat sinks 7 and 8. FIG.

  Examples of the second bonding target members 3 and 4 include a substrate formed of ceramic, plastic, or the like.

  When the average thickness of the joints 5 and 6 is T, the average diameter in the thickness direction of the joints 5 and 6 of the conductive particles 21 after joining is preferably 0.6 T or more, more preferably 0.8 T or more. More preferably, it is 0.9T or more, Especially preferably, it is 0.95T or more, Preferably it is 1T or less. When such a thickness relationship is satisfied, the distance between the first and second members to be joined can be controlled with high accuracy. The average thickness of the bonding parts 5 and 6 may be equal to the average diameter of the conductive particles 21 after bonding.

  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.

  In the following examples and comparative examples, the particle diameter of the resin particles, the particle diameter of the organic-inorganic hybrid particles, and the thickness of the inorganic shell were determined by the following methods.

  About resin particles and organic-inorganic hybrid particles, a particle image of 3000 times is taken with a scanning electron microscope (“S-3500N” manufactured by Hitachi High-Technology Corporation), and the particle diameter of 50 particles in the obtained image is vernier caliper. And the number average was determined to determine the particle sizes of the resin particles and the organic-inorganic hybrid particles.

  The particle size of the organic core (resin particles) used when producing the organic / inorganic hybrid particles was also measured by the same method as described above. The thickness of the inorganic shell was determined from the difference between the particle size of the organic-inorganic hybrid particles and the particle size of the organic core.

  The following conductive particles A to R and 1 to 8 were prepared. In the conductive particles A to R and 1 to 8, the substrate particles are resin particles. The specific gravity was adjusted by the plating film thickness.

  (1) Conductive particles A (particle diameter 50 μm, a copper layer having a thickness of 2 μm is formed on the surface of divinylbenzene resin particles, and the surface of the copper layer is treated with benzotriazole for rust prevention, particle diameter 54 μm, Specific gravity 2.8)

  (2) Conductive particles B (particle diameter 94 μm, a copper layer having a thickness of 3 μm is formed on the surface of divinylbenzene resin particles, and the surface of the copper layer is rust-prevented with benzotriazole, particle diameter 100 μm, Specific gravity 2.5)

  (3) Conductive particles C (particle diameter: 8 μm, a copper layer having a thickness of 0.3 μm is formed on the surface of divinylbenzene resin particles, and the surface of the copper layer is treated with benzotriazole to prevent rust. 9μm, specific gravity 2.5)

  (4) Conductive particles D (particle diameter 50 μm, a copper layer having a thickness of 4 μm is formed on the surface of divinylbenzene resin particles, and the surface of the copper layer is rust-prevented with benzotriazole, particle diameter 58 μm, Specific gravity 4.0)

  (5) Conductive particles E (particle size: 50 μm, a copper layer having a thickness of 0.5 μm is formed on the surface of divinylbenzene resin particles, and the surface of the copper layer is rust-prevented with benzotriazole) 51μm, specific gravity 1.7)

  (6) Conductive particles F (particle diameter of 50 μm, divinylbenzene resin particles having a 2 μm thick copper layer formed thereon, and a nickel layer formed on the outer surface of the copper layer, a particle diameter of 54 μm, Specific gravity 2.8)

  (7) Conductive particles G (particle diameter 94 μm, a copper layer having a thickness of 3 μm is formed on the surface of divinylbenzene resin particles, and a nickel layer is formed on the outer surface of the copper layer, a particle diameter of 100 μm, Specific gravity 2.5)

  (8) Conductive particles H (particle diameter 8 μm, a particle layer having a copper layer with a thickness of 0.3 μm formed on the surface of divinylbenzene resin particles and a nickel layer formed on the outer surface of the copper layer) 9μm, specific gravity 2.5)

  (9) Conductive particles I (particles having a particle diameter of 50 μm, a copper layer having a thickness of 4 μm formed on the surface of divinylbenzene resin particles, and a nickel layer having a thickness of 50 nm formed on the outer surface of the copper layer) (Diameter 58μm, specific gravity 4.0)

  (10) Conductive particles J (particle diameter 50 μm, a copper layer having a thickness of 0.5 μm is formed on the surface of divinylbenzene resin particles, and a nickel layer having a thickness of 50 nm is formed on the outer surface of the copper layer. , Particle diameter 51 μm, specific gravity 1.7)

  (11) Conductive particles K (particles having a particle diameter of 50 μm, a copper layer having a thickness of 2 μm formed on the surface of divinylbenzene resin particles, and a gold layer having a thickness of 20 nm formed on the outer surface of the copper layer) Diameter 54μm, specific gravity 2.8)

  (12) Conductive particles L (particles having a particle diameter of 50 μm, a copper layer having a thickness of 2 μm formed on the surface of divinylbenzene resin particles, and a silver layer having a thickness of 20 nm formed on the outer surface of the copper layer) Diameter 54μm, specific gravity 2.8)

  (13) Conductive particles M (conducting particles having a particle diameter of 8 μm, a copper layer having a thickness of 0.2 μm formed on the surface of divinylbenzene resin particles, and tin and silver having a thickness of 100 nm on the outer surface of the copper layer) A layer (melting point 221 ° C.) is formed, particle diameter 9 μm, specific gravity 2.7)

  (14) Conductive particle O (particle diameter 120 μm, a copper layer having a thickness of 3.5 μm is formed on the surface of divinylbenzene resin particles, and the surface of the copper layer is rust-prevented with benzotriazole. 127 μm, specific gravity 2.4)

  (15) Conductive particles P (particle diameter 120 μm, a copper layer having a thickness of 3.5 μm is formed on the surface of the divinylbenzene resin particles, and a nickel layer having a thickness of 50 nm is formed on the outer surface of the copper layer. , Particle diameter 128 μm, specific gravity 2.4)

  (16) Conductive particles Q (particle diameter: 190 μm, a divinylbenzene resin particle having a 3.5 μm thick copper layer formed thereon, and the surface of the copper layer is rust-prevented with benzotriazole; 197μm, specific gravity 2.2)

  (17) Conductive particles R (particle diameter 190 μm, a copper layer having a thickness of 3.5 μm is formed on the surface of divinylbenzene resin particles, and a nickel layer having a thickness of 50 nm is formed on the outer surface of the copper layer. , Particle size 198μm, specific gravity 2.2)

  (18) Conductive particles 1 (particle diameter: 5 μm, a divinylbenzene resin particle having a 0.2 μm thick copper layer formed thereon, and the surface of the copper layer is rust-prevented with benzotriazole; 5μm, specific gravity 2.4)

  (19) Conductive particles 2 (particle diameter: 210 μm, a copper layer having a thickness of 3.5 μm is formed on the surface of divinylbenzene resin particles, and the surface of the copper layer is treated with benzotriazole to prevent rust. 217 μm, specific gravity 2.1)

  (20) Conductive particles 3 (particle size: 50 μm, a copper layer having a thickness of 0.1 μm is formed on the surface of divinylbenzene resin particles, and the surface of the copper layer is rust-prevented with benzotriazole) 50μm, specific gravity 1.3)

  (21) Conductive particles 4 (particle diameter: 39 μm, a copper layer having a thickness of 7 μm is formed on the surface of divinylbenzene resin particles, and the surface of the copper layer is rust-prevented with benzotriazole, a particle diameter of 53 μm, Specific gravity 5.9)

  (22) Conductive particles 5 (particle diameter 5 μm, a copper layer having a thickness of 0.1 μm is formed on the surface of divinylbenzene resin particles, and a nickel layer having a thickness of 50 nm is formed on the outer surface of the copper layer. , Particle diameter 5 μm, specific gravity 2.7)

  (23) Conductive particles 6 (particle diameter 210 μm, a copper layer having a thickness of 3.5 μm is formed on the surface of divinylbenzene resin particles, and a nickel layer having a thickness of 50 nm is formed on the outer surface of the copper layer. , Particle size 218 μm, specific gravity 2.2)

  (24) Conductive particles 7 (particle diameter is 50 μm, a copper layer having a thickness of 0.1 μm is formed on the surface of divinylbenzene resin particles, and a nickel layer having a thickness of 50 nm is formed on the outer surface of the copper layer. , Particle diameter 50 μm, specific gravity 1.3)

  (25) Conductive particles 8 (particles having a particle diameter of 39 μm, a 7 μm thick copper layer formed on the surface of divinylbenzene resin particles, and a 50 nm thick nickel layer formed on the outer surface of the copper layer) Diameter 53μm, specific gravity 5.9)

Example 1
In 100 parts by weight of solder melted by heating (containing 100% by weight of tin and 3.5% by weight of silver, melting point 221 ° C.), 1 part by weight of the conductive particles A is dispersed, and then the solder is solidified. A solder sheet having a thickness of 150 μm was obtained.

(Examples 2-17 and Comparative Examples 1-8)
A solder sheet having a thickness of 150 μm was obtained in the same manner as in Example 1 except that the type of conductive particles was changed as shown in Table 1 below.

  The following conductive particles AX to RX and 1X to 8X were prepared. In the conductive particles AX to RX, 1X to 8X, the base particle is an organic-inorganic hybrid particle having an organic core and an inorganic shell disposed on the surface of the organic core. The specific gravity was adjusted by the plating film thickness. The organic-inorganic hybrid particles are core-shell type organic-inorganic hybrid particles (base material particles) in which the surface of divinylbenzene copolymer resin particles is coated with an inorganic shell (thickness: 250 nm) using a condensation reaction by a sol-gel reaction.

  (1) Conductive particles AX (particle diameter 50 μm, a copper layer having a thickness of 2 μm is formed on the surface of the organic-inorganic hybrid particles, and the surface of the copper layer is rust-prevented with benzotriazole, a particle diameter of 54 μm, Specific gravity 3.0)

  (2) Conductive particles BX (particle size 94 μm, a 3 μm thick copper layer is formed on the surface of the organic-inorganic hybrid particles, and the surface of the copper layer is rust-prevented with benzotriazole, a particle size of 100 μm, Specific gravity 2.6)

  (3) Conductive particles CX (particle diameter 8 μm, a copper layer having a thickness of 0.3 μm is formed on the surface of the organic-inorganic hybrid particles, and the surface of the copper layer is rust-prevented with benzotriazole, particle diameter 9μm, specific gravity 2.7)

  (4) Conductive particles DX (particle diameter 50 μm, a copper layer having a thickness of 4 μm is formed on the surface of the organic-inorganic hybrid particle, and the surface of the copper layer is rust-prevented with benzotriazole, a particle diameter of 58 μm, Specific gravity 4.0)

  (5) Conductive particles EX (particle diameter 50 μm, a copper layer having a thickness of 0.5 μm is formed on the surface of the organic-inorganic hybrid particles, and the surface of the copper layer is rust-prevented with benzotriazole, particle diameter 51μm, specific gravity 1.9)

  (6) Conductive particles FX (particle diameter of 50 μm, a copper layer having a thickness of 2 μm is formed on the surface of the organic-inorganic hybrid particle, and a nickel layer is formed on the outer surface of the copper layer, a particle diameter of 54 μm, Specific gravity 3.2)

  (7) Conductive particles GX (particle diameter 94 μm, a copper layer having a thickness of 3 μm is formed on the surface of the organic-inorganic hybrid particles, and a nickel layer is formed on the outer surface of the copper layer, a particle diameter of 100 μm, Specific gravity 2.6)

  (8) Conductive particles HX (particle diameter: 8 μm, a copper layer having a thickness of 0.3 μm is formed on the surface of the organic-inorganic hybrid particle, and a nickel layer is formed on the outer surface of the copper layer) 9μm, specific gravity 2.7)

  (9) Conductive particles IX (particles having a particle diameter of 50 μm, a copper layer having a thickness of 4 μm formed on the surface of the organic-inorganic hybrid particles, and a nickel layer having a thickness of 50 nm formed on the outer surface of the copper layer) (Diameter 58μm, specific gravity 4.0)

  (10) Conductive particles JX (particle diameter 50 μm, a 0.5 μm thick copper layer is formed on the surface of the organic-inorganic hybrid particles, and a 50 nm thick nickel layer is formed on the outer surface of the copper layer. , Particle diameter 51 μm, specific gravity 1.9)

  (11) Conductive particles KX (particle size 50 μm, particles having a 2 μm thick copper layer formed on the surface of the organic-inorganic hybrid particles, and a gold layer having a thickness of 20 nm formed on the outer surface of the copper layer) Diameter 54μm, specific gravity 3.0)

  (12) Conductive particles LX (particle diameter 50 μm, particles having a 2 μm thick copper layer formed on the surface of the organic-inorganic hybrid particles, and a silver layer having a thickness of 20 nm formed on the outer surface of the copper layer) Diameter 54μm, specific gravity 3.0)

  (13) Conductive particles MX (a particle diameter of 8 μm, a copper layer having a thickness of 0.2 μm is formed on the surface of the organic-inorganic hybrid particles, and a conductive material containing tin and silver having a thickness of 100 nm on the outer surface of the copper layer) Layer (melting point 221 ° C.), particle diameter 9 μm, specific gravity 2.9)

  (14) Conductive particle OX (particle diameter 120 μm, a copper layer having a thickness of 3.5 μm is formed on the surface of the organic-inorganic hybrid particle, and the surface of the copper layer is rust-prevented with benzotriazole. 127μm, specific gravity 2.5)

  (15) Conductive particles PX (particle diameter 120 μm, a copper layer having a thickness of 3.5 μm is formed on the surface of the organic-inorganic hybrid particle, and a nickel layer having a thickness of 50 nm is formed on the outer surface of the copper layer. , Particle size 128μm, specific gravity 2.5)

  (16) Conductive particles QX (particle diameter 190 μm, a copper layer having a thickness of 3.5 μm is formed on the surface of organic-inorganic hybrid particles, and the surface of the copper layer is rust-prevented with benzotriazole, particle diameter 197 μm, specific gravity 2.3)

  (17) Conductive particle RX (particle diameter 190 μm, a copper layer having a thickness of 3.5 μm is formed on the surface of the organic-inorganic hybrid particle, and a nickel layer having a thickness of 50 nm is formed on the outer surface of the copper layer. , Particle size 198 μm, specific gravity 2.3)

  (18) Conductive particles 1X (particle diameter 5 μm, a copper layer having a thickness of 0.2 μm is formed on the surface of the organic-inorganic hybrid particles, and the surface of the copper layer is rust-prevented with benzotriazole) 5μm, specific gravity 2.6)

  (19) Conductive particles 2X (particle diameter 210 μm, a copper layer having a thickness of 3.5 μm is formed on the surface of the organic-inorganic hybrid particle, and the surface of the copper layer is rust-prevented with benzotriazole, particle diameter 217 μm, specific gravity 2.2)

  (20) Conductive particles 3X (particle size 50 μm, a copper layer having a thickness of 0.1 μm is formed on the surface of the organic-inorganic hybrid particles, and the surface of the copper layer is rust-prevented with benzotriazole) 50μm, specific gravity 1.4)

  (21) Conductive particles 4X (particle size: 39 μm, a 7 μm thick copper layer is formed on the surface of the organic-inorganic hybrid particles, and the surface of the copper layer is rust-prevented with benzotriazole, a particle size of 53 μm, Specific gravity 6.1)

  (22) Conductive particles 5X (particle diameter 5 μm, a 0.1 μm thick copper layer is formed on the surface of the organic-inorganic hybrid particles, and a 50 nm thick nickel layer is formed on the outer surface of the copper layer. , Particle diameter 5 μm, specific gravity 2.9)

  (23) Conductive particles 6X (particle diameter 210 μm, a copper layer having a thickness of 3.5 μm is formed on the surface of the organic-inorganic hybrid particle, and a nickel layer having a thickness of 50 nm is formed on the outer surface of the copper layer. , Particle size 218 μm, specific gravity 2.3)

  (24) Conductive particles 7X (particle diameter 50 μm, a copper layer having a thickness of 0.1 μm is formed on the surface of the organic-inorganic hybrid particle, and a nickel layer having a thickness of 50 nm is formed on the outer surface of the copper layer. , Particle diameter 50 μm, specific gravity 1.5)

  (25) Conductive particles 8X (particle diameter: 39 μm, particles having a 7 μm thick copper layer formed on the surface of the organic-inorganic hybrid particles, and a nickel layer having a thickness of 50 nm formed on the outer surface of the copper layer) Diameter 53μm, specific gravity 6.1)

(Example 18)
In 100 parts by weight of solder melted by heating (including 100% by weight of tin and 3.5% by weight of silver, melting point 221 ° C.), 1 part by weight of the conductive particles AX is dispersed, and then the solder is solidified. A solder sheet having a thickness of 150 μm was obtained.

(Examples 19 to 34 and Comparative Examples 9 to 16)
A solder sheet having a thickness of 150 μm was obtained in the same manner as in Example 18 except that the type of conductive particles was changed as shown in Table 2 below.

(Evaluation)
(1) Production of bonded structure A power semiconductor element was prepared as a first bonding target member. An aluminum nitride substrate was prepared as the second member to be joined.

  The obtained solder sheet was laminated on the second joining target member. Next, the first member to be joined was laminated on the solder sheet to obtain a laminate. By heating the obtained laminate at 300 ° C. for 10 minutes, the solder contained in the solder sheet was melted, and then the solder was solidified to form a joint including the solder and conductive particles. . Thus, the said 1st, 2nd joining object member was joined with the solder, and the joining structure body was obtained.

(2) Thickness variation The edge part of the obtained joining structure was observed with SEM, and the minimum thickness and the maximum thickness of the joining part were evaluated. The thickness variation was determined according to the following criteria. In addition, there exists a tendency which can suppress that the heat dissipation of a junction part falls partially, so that thickness dispersion | variation is small.

[Criteria for thickness variation]
○: Maximum thickness is less than 1.2 times the minimum thickness ○: Maximum thickness is 1.2 times or more and less than 1.5 times the minimum thickness ×: Maximum thickness is 1.5 times or more the minimum thickness

(3) Heat dissipation The heat dissipation was evaluated by measuring the thermal resistance of the bonded structure obtained by the thermal resistance measuring device. The heat dissipation was determined according to the following criteria.

[Criteria for heat dissipation]
○○: Less than 0.10 ° C / W ○: 0.10 ° C / W or more, less than 0.30 ° C / W ×: 0.30 ° C / W or more

(4) Joining strength The joining strength (joining reliability) was evaluated by measuring the shear strength of the obtained joined structure. The bonding strength was determined according to the following criteria.

○○: 10 MPa or more ○: 5 MPa or more, less than 10 MPa ×: less than 5 MPa

(5) Bonding reliability After the obtained bonded structure was allowed to stand at 250 ° C. for 500 hours, the shear strength was measured by the same method as the bonding strength to evaluate the bonding reliability. Bonding reliability was determined according to the following criteria.

[Judgment criteria for bonding reliability]
○○: Shear strength is 0.90 times or more of joint strength ○: Shear strength is 0.60 times or more and less than 0.90 times of joint strength ×: Shear strength is less than 0.60 times of joint strength

(6) Relationship between the average thickness of the joint and the average diameter of the conductive particles By observing a cross section of the obtained bonded structure, the average thickness T of the joint and the joint of the conductive particles after joining The average diameter in the thickness direction was evaluated.

(7) Compressive elastic modulus of conductive particles (5% K value)
The 5% K value of the conductive particles was measured using a micro-compression tester (Fischer Scope H-100, manufactured by Fischer) under the condition described above at 23 ° C.

  The results are shown in Tables 1 and 2 below. In the evaluation of (2) thickness variation, when the thickness variation of the cross section of the obtained bonded structure was also evaluated, the determination results of the thickness variation in Examples and Comparative Examples are the same as the results shown in Tables 1 and 2. there were.

DESCRIPTION OF SYMBOLS 1 ... Joining structure 2 ... 1st joining object member 2a ... 1st surface 2b ... 2nd surface 3, 4 ... 2nd joining object member 5, 6 ... Joining part 7, 8 ... Heat sink 11 ... Solder sheet DESCRIPTION OF SYMBOLS 16 ... Solder 21 ... Conductive particle 22 ... Resin particle 22a ... Surface 23 ... Conductive layer 31 ... Conductive particle 32 ... Conductive layer 32A ... 1st conductive layer 32B ... 2nd conductive layer 41 ... Conductive particle 42 ... Organic Inorganic hybrid particles 42A ... organic core 42B ... inorganic shell 42a ... surface 43 ... conductive layer

Claims (10)

Conductive particles dispersed in solder and used as solder paste or solder sheet,
Comprising base material particles and a conductive layer disposed on the surface of the base material particles,
The substrate particles are resin particles or organic-inorganic hybrid particles,
Specific gravity is 1.5 or more and 4.0 or less,
Conductive particles having a particle size of 8 μm or more and 200 μm or less.   The conductive particle according to claim 1, wherein the conductive layer has a copper layer. Comprising the base particle, a copper layer disposed on the surface of the base particle, and a second conductive layer disposed on the outer surface of the copper layer, or
3. The conductive particle according to claim 1, comprising the base material particle and a copper layer disposed on the surface of the base material particle, and the outer surface of the copper layer is subjected to rust prevention treatment. .   The electroconductivity of Claim 3 provided with the said base material particle, the copper layer arrange | positioned on the surface of the said base material particle, and the 2nd conductive layer arrange | positioned on the outer surface of the said copper layer. particle.   5. The conductive particle according to claim 3, wherein the second conductive layer contains nickel, gold, silver, or tin.   The electroconductive particle of Claim 3 provided with the said base material particle and the copper layer arrange | positioned on the surface of the said base material particle, and the surface of the outer side of the said copper layer is rust-proofed.   The electroconductive particle of any one of Claims 1-6 whose said base material particle is the said resin particle.   The electroconductive particle of any one of Claims 1-6 whose said base material particle is the said organic-inorganic hybrid particle.   The electroconductive particle of any one of Claims 1-8 disperse | distributed in solder and used as a solder sheet.   A solder joint material comprising the conductive particles according to claim 1 and solder and being a solder paste or a solder sheet.

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