JP2019175844A - Conductive material, connection structure and method for producing connection structure - Google Patents

Abstract

To provide a conductive material that can efficiently arrange a solder on an electrode.SOLUTION: A conductive material contains a thermosetting component, and a plurality of conductive particles. The conductive particles contains solder particles. When the temperature is raised from 25°C to 160°C at 1.0°C/sec., the wetting time is 3 seconds or more and 25 seconds or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a conductive material including a thermosetting component and conductive particles. The present invention also relates to a connection structure using the conductive material and a method for manufacturing the connection structure.

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

  The anisotropic conductive material is used to obtain various connection structures. Examples of the connection using the anisotropic conductive material include a connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)), a connection between a semiconductor chip and a flexible printed circuit board (COF (Chip on Film)), and a semiconductor. Examples include connection between a 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 electrically connecting the electrode of the flexible printed circuit board and the electrode of the glass epoxy substrate by the anisotropic conductive material, an anisotropic conductive material containing conductive particles is disposed on the glass epoxy substrate. To do. Next, a flexible printed circuit board is laminated, 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.

The following Patent Document 1 discloses an adhesive tape that electrically connects conductor members. The adhesive tape includes a resin layer containing a thermosetting resin, solder powder, and a curing agent. The solder powder and the curing agent are present in the resin layer. In the above adhesive tape, the melting point T ₂ of the curing temperature T ₁ of the above solder powder of the resin layer satisfies the following formula (1).

T ₁ ≧ T ₂ +20 Formula (1)

The curing temperatures T _1, using the DSC, an exothermic peak temperature when measuring the adhesive tape at a heating rate of 10 ° C. / min. In the above adhesive tape, the melt viscosity of the resin layer at the melting point _{T 2} of the said solder powder is less than or equal to 50 Pa · s or more 5000 Pa · s.

  Patent Document 2 below discloses a thermosetting resin composition containing solder particles, a thermosetting resin binder, and a flux component. The solder particles are composed of an alloy of Sn and a metal selected from Ag, Cu, Bi, Zn, or In. The melting point of the solder particles is 240 ° C. or less. The thermosetting resin binder includes a liquid epoxy resin and a liquid phenol resin curing agent. In the said thermosetting resin composition, content of the said solder particle is the range of 70 mass%-95 mass%. The solder particles are dispersed in the thermosetting resin composition. The said thermosetting resin composition can be apply | coated to the surface of a wiring board.

WO2008 / 023452A1 JP 2014-98168 A

  When conducting a conductive connection using a conductive material containing solder particles, the plurality of upper electrodes and the plurality of lower electrodes are electrically connected to perform conductive connection. It is desirable that the solder particles be disposed between the upper and lower electrodes and not be disposed between adjacent lateral electrodes. It is desirable that the adjacent lateral electrodes are not electrically connected.

  In general, a conductive material containing solder particles is used after being placed on a substrate and then heated by reflow or the like. When the conductive material is heated to the melting point or higher of the solder particles, the solder particles are melted and the solder is aggregated between the electrodes, so that the upper and lower electrodes are electrically connected.

  In a conductive material containing conventional solder particles, the solder agglomeration rate is too fast, so that the solder remains between adjacent lateral electrodes and all the solder cannot agglomerate on the electrodes and should be connected Solder may not be efficiently arranged between the upper and lower electrodes. As a result, the amount of solder disposed between the upper and lower electrodes to be connected is reduced, the conduction reliability between the upper and lower electrodes to be connected is lowered, or the insulation reliability between adjacent lateral electrodes is reduced. May be lowered. With conventional conductive materials, it is difficult to adjust the cohesive strength of solder.

  An object of the present invention is to provide a conductive material capable of efficiently arranging solder on an electrode. Another object of the present invention is to provide a connection structure using the conductive material and a method for manufacturing the connection structure.

  According to a wide aspect of the present invention, a thermosetting component and a plurality of conductive particles are included, and the conductive particles include solder particles, and the temperature is increased from 25 ° C. to 160 ° C. at a rate of 1.0 ° C./second. A conductive material having a wetting time of 3 seconds or more and 25 seconds or less is provided.

  In a specific aspect of the conductive material according to the present invention, the wetting time when the temperature is raised from 25 ° C. to 160 ° C. at 1.0 ° C./second is from 5 seconds to 17 seconds.

  In a specific aspect of the conductive material according to the present invention, the wetting force at 160 ° C. is 1.5 mN or more and 3.4 mN or less.

  On the specific situation with the electrically-conductive material which concerns on this invention, content of the said electroconductive particle is 40 to 90 weight% in 100 weight% of electrically-conductive materials.

  On the specific situation with the electrically-conductive material which concerns on this invention, content of the said solder particle is 50 weight% or more in 100 weight% of said conductive particles.

  On the specific situation with the electrically-conductive material which concerns on this invention, the particle diameter of the said solder particle is 0.01 micrometer or more and 30 micrometers or less.

  On the specific situation with the electrically-conductive material which concerns on this invention, melting | fusing point of the said solder particle is 139 degreeC or more and 221 degrees C or less.

  In a specific aspect of the conductive material according to the present invention, the conductive material is a conductive paste.

  According to a wide aspect of the present invention, a first connection target member having a first electrode on the surface, a second connection target member having a second electrode on the surface, the first connection target member, A connecting portion connecting the second connection target member, wherein the material of the connecting portion is the conductive material described above, and the first electrode and the second electrode are the connecting portion. A connection structure is provided that is electrically connected by a solder portion therein.

  In a specific aspect of the connection structure according to the present invention, the first electrode and the second electrode face each other in the stacking direction of the first electrode, the connection portion, and the second electrode. When the portion is viewed, the solder portion in the connection portion is arranged in 50% or more of the area of 100% of the portion where the first electrode and the second electrode face each other.

  According to a wide aspect of the present invention, using the conductive material described above, the step of disposing the conductive material on the surface of the first connection target member having the first electrode on the surface; On the surface opposite to the first connection target member side, the second connection target member having the second electrode on the surface is arranged so that the first electrode and the second electrode face each other. Forming a connection portion connecting the first connection target member and the second connection target member with the conductive material by heating the conductive material to a temperature equal to or higher than the melting point of the solder particles; And the manufacturing method of a connection structure provided with the process of electrically connecting a said 1st electrode and a said 2nd electrode with the solder part in the said connection part is provided.

  In a specific aspect of the manufacturing method of the connection structure according to the present invention, the first electrode and the second electrode are stacked in the stacking direction of the first electrode, the connection portion, and the second electrode. A connection in which the solder part in the connection part is arranged in 50% or more of the area of 100% of the part where the first electrode and the second electrode face each other when the part facing each other is viewed. Get a structure.

  The conductive material according to the present invention includes a thermosetting component and a plurality of conductive particles. In the conductive material according to the present invention, the conductive particles include solder particles. In the conductive material according to the present invention, the wetting time when the temperature is raised from 25 ° C. to 160 ° C. at 1.0 ° C./second is from 3 seconds to 25 seconds. Since the conductive material according to the present invention has the above-described configuration, it is possible to efficiently arrange the solder on the electrode.

FIG. 1 is a cross-sectional view schematically showing a connection structure obtained using a conductive material according to an embodiment of the present invention. 2A to 2C are cross-sectional views for explaining each step of an example of a method for manufacturing a connection structure using a conductive material according to an embodiment of the present invention. FIG. 3 is a cross-sectional view showing a modification of the connection structure. FIG. 4 is a cross-sectional view showing conductive particles that can be used in the conductive material according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view showing conductive particles that can be used in the conductive material according to the second embodiment of the present invention. FIG. 6 is a cross-sectional view showing conductive particles that can be used in the conductive material according to the third embodiment of the present invention. FIG. 7 is a diagram for explaining the wetting time in the conductive material according to the present invention.

  Details of the present invention will be described below.

(Conductive material)
The conductive material according to the present invention includes a thermosetting component and a plurality of conductive particles. In the conductive material according to the present invention, the conductive particles include solder particles. In the conductive material according to the present invention, the wetting time when the temperature is raised from 25 ° C. to 160 ° C. at 1.0 ° C./second is from 3 seconds to 25 seconds.

  Since the conductive material according to the present invention has the above-described configuration, it is possible to efficiently arrange the solder on the electrode.

  The conductive material containing the solder particles is used after being placed on the substrate and then heated by reflow or the like. When the conductive material is heated above the melting point of the solder particles, the solder particles are melted and the solder pieces are aggregated between the electrodes, so that the upper and lower electrodes are electrically connected.

  In a conductive material containing conventional solder particles, the solder agglomeration rate is too fast, so that the solder remains between adjacent lateral electrodes and all the solder cannot agglomerate on the electrodes and should be connected Solder may not be efficiently arranged between the upper and lower electrodes.

  The present inventors have found that the cohesive strength of solder can be adjusted by using specific conductive particles. In the present invention, the solder can be efficiently arranged on the electrode by appropriately adjusting the cohesive force of the solder.

  Moreover, the solder remaining between adjacent lateral electrodes can be reduced by appropriately adjusting the cohesive force of the solder. As a result, it is possible to effectively increase the insulation reliability between adjacent lateral electrodes that should not be connected.

  Further, by appropriately adjusting the cohesive force of the solder, it is possible to sufficiently ensure the amount of solder disposed between the upper and lower electrodes to be connected. As a result, the conduction reliability between the upper and lower electrodes to be connected can be effectively increased.

  In the present invention, since the above-described configuration is provided, when the electrodes are electrically connected, the solder is likely to gather between the upper and lower electrodes, and the solder is disposed on the electrode (line). Can do. Further, it is difficult for a part of the solder to be disposed between the lateral electrodes that should not be connected, and the amount of solder disposed between the lateral electrodes that should not be connected can be considerably reduced. As a result, according to the present invention, it is possible to reduce the remaining amount of solder between the lateral electrodes that should not be connected.

  In this invention, in order to acquire the above effects, it will contribute greatly that the said electrically-conductive material contains specific electroconductive particle.

  Furthermore, in the present invention, it is possible to prevent positional deviation between the electrodes. In the present invention, when the second connection target member is superimposed on the first connection target member having the conductive material disposed on the upper surface, the electrode of the first connection target member and the electrode of the second connection target member Even in a state of misalignment, the electrodes can be connected by correcting the misalignment (self-alignment effect).

  From the viewpoint of more efficiently arranging the solder on the electrode, the conductive material is preferably liquid at 25 ° C., and preferably a conductive paste.

  From the viewpoint of more efficiently arranging the solder on the electrode, the viscosity (η25) at 25 ° C. of the conductive material is preferably 0.1 Pa · s or more, more preferably 10 Pa · s or more, and still more preferably. It is 30 Pa · s or more, particularly preferably 50 Pa · s or more, preferably 400 Pa · s or less, more preferably 300 Pa · s or less. The said viscosity ((eta) 25) can be suitably adjusted with the kind and compounding quantity of a compounding component.

  The viscosity (η25) can be measured, for example, using an E-type viscometer (“TVE22L” manufactured by Toki Sangyo Co., Ltd.) and the like at 25 ° C. and 5 rpm.

  The wetting time when the conductive material is heated from 25 ° C. to 160 ° C. at a rate of 1.0 ° C./second is 3 seconds to 25 seconds. From the viewpoint of more efficiently arranging the solder on the electrode, the wetting time when the conductive material is heated from 25 ° C. to 160 ° C. at 1.0 ° C./second is preferably 5 seconds or more. Preferably it is 10 seconds or more, preferably 17 seconds or less, more preferably 14 seconds or less.

  The wetting time when the conductive material is heated from 25 ° C. to 160 ° C. at a rate of 1.0 ° C./second can be determined by a solder wettability tester. Examples of the solder wettability tester include “Wettability tester (SP2)” manufactured by Malcolm. About the obtained graph (refer FIG. 7), the straight line (L1 in FIG. 7) which extended the base line of the curve (C in FIG. 7) which shows a wetting force is drawn. The time at the first intersection (X1 in FIG. 7) between the straight line and the curve indicating the wetting force is calculated. For the obtained graph, the maximum value of the wetting force when the wetting force reaches equilibrium (S in FIG. 7) is defined as the maximum wetting force. A straight line (L2 in FIG. 7) that is 2/3 times the maximum wetting force in the obtained graph and is parallel to L1 is drawn. The time at the last intersection (X2 in FIG. 7) between the straight line and the curve indicating the wetting force until the wetting force reaches equilibrium is calculated. The difference (X2−X1) between the time at X1 and the time at X2 is defined as the wetting time when the temperature is raised from 25 ° C. to 160 ° C. at 1.0 ° C./second. In the curve indicating the wetting force, a peak (P in FIG. 7) that appears before the wetting force reaches equilibrium is processed as a noise peak. When a noise peak appears on the curve indicating the wetting force, the maximum wetting force is calculated without considering the noise peak.

  Examples of a method for adjusting the wetting time when the conductive material is heated from 25 ° C. to 160 ° C. at a rate of 1.0 ° C./second within the preferable range include a method for adjusting the fluidity of the conductive particles. Can be mentioned. Specifically, the method of adjusting the melting point of the solder particles and the melting point of conductive particles other than the solder particles, the method of using solder particles having different melting points, and the content of solder in the conductive particles are adjusted. And the like.

  From the viewpoint of more efficiently arranging the solder on the electrode, the wetting force of the conductive material at 160 ° C. is preferably 1.5 mN (0.00015 kgf) or more, more preferably 2.0 mN (0.0002 kgf). ) Or more, preferably 3.4 mN (0.00034 kgf) or less, more preferably 2.9 mN (0.00029 kgf) or less.

  The wetting force at 160 ° C. of the conductive material can be obtained by a solder wettability tester. Examples of the solder wettability tester include “Wettability tester (SP2)” manufactured by Malcolm. The maximum wetting force in the obtained graph is the wetting force at 160 ° C.

  Examples of a method for adjusting the wetting force of the conductive material at 160 ° C. to the above preferable range include a method for adjusting the fluidity of the conductive particle powder. Specifically, the method of adjusting the melting point of the solder particles and the melting point of conductive particles other than the solder particles, the method of using solder particles having different melting points, and the content of solder in the conductive particles are adjusted. Methods and the like.

  The conductive material can be used as a conductive paste and a conductive film. The conductive paste is preferably an anisotropic conductive paste, and the conductive film is preferably an anisotropic conductive film. From the viewpoint of more efficiently disposing the solder on the electrode, the conductive material is preferably a conductive paste. The conductive material is preferably used for electrical connection of electrodes. The conductive material is preferably a circuit connection material.

  Hereinafter, each component contained in the conductive material will be described.

(Conductive particles)
The conductive material includes a plurality of conductive particles. The conductive particles include solder particles. The conductive particles may contain only solder particles, or may contain solder particles and conductive particles other than the solder particles.

  The content of the conductive particles in 100% by weight of the conductive material is preferably 40% by weight or more, more preferably 45% by weight or more, further preferably 55% by weight or more, and particularly preferably 60% by weight or more. Is 90% by weight or less, more preferably 85% by weight or less, and still more preferably 80% by weight or less. When the content of the conductive particles is not less than the above lower limit and not more than the above upper limit, it is possible to more efficiently arrange the solder on the electrodes, and it is easy to arrange much solder between the electrodes, The conduction reliability and the insulation reliability can be further effectively improved.

  From the viewpoint of more efficiently arranging the solder on the electrode, the content of the solder particles in the conductive particles of 100% by weight is preferably 50% by weight or more, more preferably 60% by weight or more. It is preferably 70% by weight or more, more preferably 80% by weight or more, particularly preferably 90% by weight or more, and most preferably 100% by weight.

  In the present specification, the term “100% by weight of conductive particles” means the total weight of the conductive particles contained in the conductive material.

  Next, specific examples of conductive particles will be described with reference to the drawings.

  FIG. 4 is a cross-sectional view showing conductive particles that can be used in the conductive material according to the first embodiment of the present invention.

  The conductive particles 21 shown in FIG. 4 are solder particles. The conductive particles 21 are entirely formed of solder. The conductive particles 21 do not have base particles in the core, and are not core-shell particles. As for the electroconductive particle 21, both the center part and the outer surface part of an electroconductive part are formed with the solder.

  FIG. 5 is a cross-sectional view showing conductive particles that can be used in the conductive material according to the second embodiment of the present invention.

  The conductive particle 31 shown in FIG. 5 includes a base particle 32 and a conductive part 33 disposed on the surface of the base particle 32. The conductive portion 33 covers the surface of the base particle 32. The conductive particles 31 are coated particles in which the surface of the base particle 32 is covered with the conductive portion 33.

  The conductive portion 33 includes a second conductive portion 33A and a first conductive portion 33B. The conductive particles 31 include a second conductive portion 33A between the base particle 32 and the first conductive portion 33B. Accordingly, the conductive particles 31 include the base particles 32, the second conductive portion 33A disposed on the surface of the base particles 32, and the first conductive layer 33A disposed on the outer surface of the second conductive portion 33A. And a conductive portion 33B.

  FIG. 6 is a cross-sectional view showing conductive particles that can be used in the conductive material according to the third embodiment of the present invention.

  As described above, the conductive portion 33 in the conductive particle 31 has a two-layer structure. The conductive particle 41 illustrated in FIG. 6 includes a conductive portion 42 as a single-layer conductive portion. The conductive particles 41 include base particles 32 and conductive portions 42 disposed on the surface of the base particles 32.

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

Solder particles:
As for the said solder particle, both a center part and an outer surface are formed with the solder. The solder particles are particles in which both the central portion and the outer surface are solder.

  The solder is preferably a metal (low melting point metal) having a melting point of 450 ° C. or lower. The solder particles are preferably metal particles (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 is preferably a low melting point solder having a melting point of less than 150 ° C. The solder particles preferably have a melting point of less than 150 ° C.

  From the viewpoint of more efficiently arranging the solder on the electrode, the melting point of the solder particles is preferably 139 ° C. or higher, more preferably 170 ° C. or higher, preferably 221 ° C. or lower, more preferably 217 ° C. or lower. It is.

  The melting point of the solder particles can be determined by differential scanning calorimetry (DSC). Differential scanning calorimetry (DSC) is preferably performed under conditions of a temperature increase range of 30 ° C. to 500 ° C., a temperature increase rate of 5 ° C./min and a nitrogen purge amount of 5 ml / min. Examples of the differential scanning calorimetry (DSC) apparatus include “EXSTAR DSC7020” manufactured by SII.

  The solder particles preferably contain tin. In 100% by weight of the metal contained in the solder particles, 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 tin content in the solder particles is equal to or higher than the lower limit, the conduction reliability and the connection reliability between the solder portion and the electrode are further enhanced.

  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). Can be measured.

  By using the solder particles, the solder particles are melted and joined to the electrodes, and the solder portion conducts between the electrodes. For example, since the solder portion and the electrode are not in point contact but in surface contact, the connection resistance is lowered. Moreover, as a result of the use of the solder particles, the bonding strength between the solder part and the electrode is increased. As a result, peeling between the solder part and the electrode is less likely to occur, and the conduction reliability and the connection reliability are further improved.

  The low melting point metal constituting 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. The low melting point metal is preferably tin, a tin-silver alloy, a tin-silver-copper alloy, a tin-bismuth alloy, or a tin-indium alloy because of its excellent wettability with respect to the electrode. The low melting point metal is more preferably a tin-bismuth alloy or a tin-indium alloy.

  The solder particles are preferably a filler material having a liquidus line of 450 ° C. or lower based on JIS Z3001: welding terms. Examples of the composition of the solder particles include a metal composition containing zinc, gold, silver, lead, copper, tin, bismuth, indium, and the like. A tin-indium system (117 ° C eutectic) or a tin-bismuth system (139 ° C eutectic) that has a low melting point and is free of lead is preferable. That is, 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 part and the electrode, the solder particles include nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, cobalt, bismuth, manganese, chromium, Metals such as molybdenum and palladium may be included. Moreover, from the viewpoint of further increasing the bonding strength between the solder portion and the electrode, the solder particles preferably contain nickel, copper, antimony, aluminum, or zinc. From the viewpoint of further increasing the bonding strength between the solder part and the electrode, the content of these metals for increasing the bonding strength is 100 wt% of the metal contained in the solder particles, preferably 0.0001 wt% or more, Preferably it is 1 weight% or less.

  The particle diameter of the solder particles is preferably 0.01 μm or more, more preferably 1 μm or more, further preferably 2 μm or more, preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less. When the particle diameter of the solder particles is not less than the above lower limit and not more than the above upper limit, the solder particles can be more efficiently disposed on the electrode than the solder. The particle diameter of the solder particles is particularly preferably 3 μm or more and 10 μm or less. When the particle diameter of the solder particles is less than 3 μm, an oxide film may be formed on the surface of the solder particles.

  The particle diameter of the solder particles is preferably an average particle diameter, and more preferably a number average particle diameter. The particle size of the solder particles is, for example, observing 50 arbitrary solder particles with an electron microscope or an optical microscope, calculating an average value of the particle size of each solder particle, or performing a laser diffraction particle size distribution measurement. Is required. In observation with an electron microscope or an optical microscope, the particle diameter of one solder particle is determined as a particle diameter in a circle-equivalent diameter. In observation with an electron microscope or an optical microscope, the average particle diameter at an equivalent circle diameter of any 50 solder particles is substantially equal to the average particle diameter at a sphere equivalent diameter. In the laser diffraction particle size distribution measurement, the particle diameter of one solder particle is obtained as a particle diameter in a sphere equivalent diameter. The average particle size of the solder particles is preferably calculated by laser diffraction particle size distribution measurement.

  The coefficient of variation (CV value) of the solder particle diameter is preferably 5% or more, more preferably 10% or more, preferably 40% or less, more preferably 30% or less. When the coefficient of variation of the particle diameter of the solder particles is not less than the above lower limit and not more than the above upper limit, the solder can be more efficiently arranged on the electrode. However, the CV value of the particle diameter of the solder particles may be less than 5%.

  The coefficient of variation (CV value) can be measured as follows.

CV value (%) = (ρ / Dn) × 100
ρ: Standard deviation of particle diameter of solder particles Dn: Average value of particle diameter of solder particles

  The shape of the solder particles is not particularly limited. The solder particles may have a spherical shape or a shape other than a spherical shape such as a flat shape.

Conductive particles other than solder particles (conductive particles X):
The conductive particles may be conductive particles other than the above-described solder particles (hereinafter, conductive particles other than the solder particles may be referred to as conductive particles X). The conductive particles X may have base particles and conductive portions arranged on the surface of the base particles. The conductive particles X may contain solder in the conductive part, or may not contain solder in the conductive part. The conductive portion may have a single layer structure or a multilayer structure of two or more layers. The conductive particle X includes a base particle, a second conductive part disposed on the surface of the base particle, and a first conductive part disposed on the outer surface of the second conductive part. May be provided.

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

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

  Various organic materials are suitably used as the material for the resin particles. Examples of the material for 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; 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, polyamideimide, polyetheretherketone, poly 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 material of the resin particles is a polymer obtained by polymerizing one or more polymerizable monomers having an ethylenically unsaturated group. Is preferred.

  When the resin particles are obtained by polymerizing a polymerizable monomer having an ethylenically unsaturated group, the polymerizable monomer having an ethylenically unsaturated group includes a non-crosslinkable monomer and And a crosslinkable monomer.

  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; Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, Alkyl (meth) acrylate compounds such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate, and glycidyl (meth) Oxygen atom-containing (meth) acrylate compounds such as acrylate; Nitrile-containing monomers such as (meth) acrylonitrile; Vinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether, and propyl vinyl ether; Vinyl acetate, vinyl butyrate, vinyl laurate, and stearin Acid vinyl ester compounds such as vinyl acid; unsaturated hydrocarbons such as ethylene, propylene, isoprene, and butadiene; trifluoromethyl (meth) acrylate, pentafluoroethyl (meth) acrylate, vinyl chloride, vinyl fluoride, and chlorostyrene And halogen-containing monomers such as

  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) acrylate compounds such as acrylate, (poly) tetramethylene glycol di (meth) acrylate, and 1,4-butanediol di (meth) acrylate; triallyl (iso) silane Silane-containing single quantities such as nurate, triallyl trimellitate, divinylbenzene, diallyl phthalate, diallylacrylamide, diallyl ether, and γ- (meth) acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, and vinyltrimethoxysilane Examples include the body.

  The term “(meth) acrylate” refers to acrylate and methacrylate. The term “(meth) acryl” refers to acrylic and methacrylic. The term “(meth) acryl” refers to acrylic and methacrylic.

  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, alumina, barium titanate, zirconia, and carbon black. The inorganic substance is preferably not a metal. The particles formed from the silica are not particularly limited. For example, after forming a crosslinked polymer particle by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups, firing may be performed as necessary. The particle | grains obtained by performing are mentioned. Examples of the organic / inorganic hybrid particles include organic / inorganic hybrid particles formed of a crosslinked alkoxysilyl polymer and an acrylic resin.

  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 the organic core include the material for the resin particles described above.

  Examples of the material for the inorganic shell include the inorganic materials mentioned as the material for the base material particles. The material of 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-like material by a sol-gel method and then firing the shell-like material. The metal alkoxide is preferably a silane alkoxide. The inorganic shell is preferably formed of a silane alkoxide.

  When the substrate particles are metal particles, examples of the metal that is a material of the metal particles include silver, copper, nickel, silicon, gold, and titanium.

  The particle diameter of the substrate particles is preferably 0.5 μm or more, more preferably 1 μm or more, further preferably 3 μm or more, preferably 100 μm or less, more preferably 60 μm or less, and even more preferably 50 μm or less. When the particle diameter of the substrate particles is not less than the above lower limit and not more than the above upper limit, the solder can be more efficiently arranged on the electrode. Further, when forming the conductive portion on the surface of the base particle, it becomes difficult to aggregate, and the aggregated conductive particle X is difficult to be formed.

  The particle diameter of the substrate particles is particularly preferably 5 μm or more and 40 μm or less. When the particle diameter of the substrate particles is in the range of 5 μm or more and 40 μm or less, the solder can be arranged more efficiently on the electrode.

  The particle diameter of the base particle indicates a diameter when the base particle is a true sphere, and indicates a maximum diameter when the base particle is not a true sphere.

  The particle diameter of the base particle indicates a number average particle diameter. The particle diameter of the substrate particles is determined using a particle size distribution measuring device or the like. The particle diameter of the substrate particles is preferably determined by observing 50 arbitrary substrate particles with an electron microscope or an optical microscope and calculating an average value. In observation with an electron microscope or an optical microscope, the particle diameter of the base particle per particle is obtained as a particle diameter in a circle-equivalent diameter. In observation with an electron microscope or an optical microscope, the average particle diameter at an equivalent circle diameter of any 50 base particles is substantially equal to the average particle diameter at a sphere equivalent diameter. In the particle size distribution measuring apparatus, the particle diameter of the base material particle per particle is obtained as a particle diameter in a sphere equivalent diameter. The average particle diameter of the base material particles is preferably calculated by a particle size distribution measuring device. In the case of measuring the particle diameter of the base particle in the conductive particle X, for example, it can be measured as follows.

  An embedded resin for inspecting conductive particles X is prepared by adding and dispersing in “Technobit 4000” manufactured by Kulzer so that the content of the conductive particles X is 30% by weight. A cross section of the conductive particles X is cut out using an ion milling device ("IM4000" manufactured by Hitachi High-Technologies Corporation) so as to pass through the vicinity of the center of the conductive particles X dispersed in the inspection embedding resin. Then, using a field emission scanning electron microscope (FE-SEM), the image magnification is set to 25000 times, 50 conductive particles X are randomly selected, and base particles of each conductive particle X Observe. The particle diameter of the base particle in each conductive particle X is measured, and arithmetically averaged to obtain the particle diameter of the base particle.

(Conductive part)
The method for forming the conductive part on the surface of the base particle and the method for forming the first conductive part on the surface of the base particle or the surface of the second conductive part are not particularly limited. Examples of the method for forming the conductive part include 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, and a metal powder or Examples thereof include a method of coating the surface of the substrate particles with a paste containing a metal powder and a binder. The method for forming the conductive part is preferably a method by electroless plating, electroplating or physical collision. 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 substrate particles is preferably higher than the melting point of the conductive part. 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 conductive particles X may have a single layer solder portion. The conductive particles X may have a single-layer conductive part, or may have a plurality of conductive parts (a first conductive part, a second conductive part, etc.). That is, in the conductive particle X, two or more conductive portions may be stacked. When the conductive part has two or more layers, the conductive particles X may have solder on the outer surface portion of the conductive part.

  The solder is preferably a solder having the same composition as the solder particles described above.

  The low melting point metal constituting the solder is not particularly limited. The low melting point metal is preferably a low melting point metal constituting the solder particles described above.

  The melting point of the second conductive part is preferably higher than the melting point of the first conductive part. The melting point of the second conductive part is preferably more than 160 ° C, more preferably more than 300 ° C, still more preferably more than 400 ° C, still more preferably more than 450 ° C, particularly preferably more than 500 ° C, Most preferably above 600 ° C. Since the first conductive portion has a low melting point, it melts at the time of conductive connection. It is preferable that the second conductive portion does not melt during conductive connection. The first conductive part is preferably a solder part, and is preferably used by melting the first conductive part, and the first conductive part is melted and the second conductive part is used. It is preferably used without melting. When the melting point of the second conductive part is higher than the melting point of the first conductive part, only the first conductive part is melted without melting the second conductive part during conductive connection. be able to.

  The absolute value of the difference between the melting point of the first conductive part and the melting point of the second conductive part exceeds 0 ° C, preferably 5 ° C or higher, more preferably 10 ° C or higher, and even more preferably 30 ° C or higher. Particularly preferably, it is 50 ° C. or higher, and most preferably 100 ° C. or higher.

  The second conductive part preferably contains a metal. The metal which comprises the said 2nd electroconductive part is not specifically 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 part is preferably a nickel layer, a palladium layer, a copper layer, or a gold layer, more preferably a nickel layer, a gold layer, or a copper layer, and even more preferably a copper layer. The conductive particles X preferably have a nickel layer, a palladium layer, a copper layer, or a gold layer, more preferably have a nickel layer, a gold layer, or a copper layer, and more preferably have a copper layer. By using the conductive particles X having these preferable conductive parts for the connection between the electrodes, the solder can be arranged more efficiently between the electrodes.

  The thickness of the first conductive part 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 thickness of the first conductive portion is not less than the above lower limit and not more than the above upper limit, the solder can be more efficiently disposed on the electrode, and the conduction reliability and the connection reliability can be further effectively improved. be able to.

  The particle diameter of the conductive particles X is preferably 0.5 μm or more, more preferably 1 μm or more, further preferably 3 μm or more, preferably 100 μm or less, more preferably 60 μm or less, still more preferably 50 μm or less, particularly preferably. Is 40 μm or less. When the particle diameter of the conductive particles X is not less than the above lower limit and not more than the above upper limit, the solder can be arranged more efficiently on the electrode, and the conduction reliability and the connection reliability can be more effectively improved. Can be increased.

  The particle diameter of the conductive particles X is preferably an average particle diameter, and more preferably a number average particle diameter. The average particle diameter of the conductive particles X is obtained, for example, by observing 50 arbitrary conductive particles X with an electron microscope or an optical microscope, calculating an average value, or performing laser diffraction particle size distribution measurement. . In observation with an electron microscope or an optical microscope, the particle diameter of each conductive particle X is obtained as a particle diameter in a circle-equivalent diameter. In observation with an electron microscope or an optical microscope, the average particle diameter at an equivalent circle diameter of any 50 conductive particles X is substantially equal to the average particle diameter at a sphere equivalent diameter. In the laser diffraction particle size distribution measurement, the particle diameter of each conductive particle X is obtained as a particle diameter in a sphere equivalent diameter. The average particle size of the conductive particles X is preferably calculated by laser diffraction particle size distribution measurement.

  The CV value of the particle diameter of the conductive particles X is preferably 5% or more, more preferably 10% or more, preferably 40% or less, more preferably 30% or less. When the CV value of the particle diameter is not less than the above lower limit and not more than the above upper limit, the solder can be more efficiently arranged on the electrode. However, the CV value of the particle diameter of the conductive particles X may be less than 5%.

  The CV value (coefficient of variation) of the particle diameter of the conductive particles X can be measured as follows.

CV value (%) = (ρ / Dn) × 100
ρ: Standard deviation of particle diameter of conductive particle X Dn: Average value of particle diameter of conductive particle X

  The shape of the conductive particles X is not particularly limited. The shape of the conductive particles X may be spherical, or may be a shape other than a spherical shape such as a flat shape.

  From the viewpoint of more efficiently arranging the solder on the electrode, the melting point of the conductive particle X or the conductive part is preferably higher than the melting point of the solder particle. From the viewpoint of more efficiently arranging the solder on the electrode, the melting point of the conductive particles X or the conductive part is preferably higher by 20 ° C. than the melting point of the solder particles.

  The melting point of the conductive particles X and the melting point of the conductive part can be determined by differential scanning calorimetry (DSC). Examples of the differential scanning calorimetry (DSC) apparatus include “EXSTAR DSC7020” manufactured by SII.

  In 100% by weight of the conductive material, the content of the conductive particles X is preferably 2% by weight or more, more preferably 5% by weight or more, still more preferably 7% by weight or more, and preferably 25% by weight or less. More preferably, it is 15 weight% or less, More preferably, it is 10 weight% or less. When the content of the conductive particles X is not less than the above lower limit and not more than the above upper limit, it is possible to more efficiently arrange solder on the electrodes, and it is easy to dispose much solder between the electrodes. In addition, the conduction reliability and the connection reliability can be further effectively improved.

(Thermosetting component)
The conductive material includes a thermosetting component. The conductive material may contain a thermosetting compound and a thermosetting agent as a thermosetting component. In order to cure the conductive material even better, the conductive material preferably contains a thermosetting compound and a thermosetting agent as the thermosetting component. In order to cure the conductive material even better, the conductive material preferably contains a curing accelerator as a thermosetting component.

(Thermosetting component: thermosetting compound)
The thermosetting compound is not particularly limited. Examples of the thermosetting compound include oxetane compounds, epoxy compounds, episulfide compounds, (meth) acrylic compounds, phenolic compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, silicone compounds, and polyimide compounds. From the viewpoint of further improving the curability and viscosity of the conductive material, from the viewpoint of more effectively increasing the conduction reliability, and from the viewpoint of further increasing the insulation reliability more effectively, as the thermosetting compound, Epoxy compounds or episulfide compounds are preferred, and epoxy compounds are more preferred. The thermosetting compound preferably contains an epoxy compound. As for the said thermosetting compound, only 1 type may be used and 2 or more types may be used together.

  The epoxy compound is a compound having at least one epoxy group. Examples of the epoxy compounds include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy compounds, phenol novolac type epoxy compounds, biphenyl type epoxy compounds, biphenyl novolac type epoxy compounds, biphenol type epoxy compounds, and naphthalene type epoxy compounds. Fluorene type epoxy compound, phenol aralkyl type epoxy compound, naphthol aralkyl type epoxy compound, dicyclopentadiene type epoxy compound, anthracene type epoxy compound, epoxy compound having adamantane skeleton, epoxy compound having tricyclodecane skeleton, naphthylene ether type Examples thereof include an epoxy compound and an epoxy compound having a triazine nucleus in the skeleton. As for the said epoxy compound, only 1 type may be used and 2 or more types may be used together.

  The epoxy compound is liquid or solid at normal temperature (23 ° C.), and when the epoxy compound is solid at normal temperature, the melting temperature of the epoxy compound is preferably equal to or lower than the melting point of the solder particles. By using the above-mentioned preferable epoxy compound, the first connection target member and the second connection are high when the connection target member is pasted and when the viscosity is high and acceleration is applied by impact such as conveyance. The positional deviation with respect to the target member can be suppressed. Furthermore, the viscosity of the conductive material can be greatly reduced by heat at the time of curing, and the solder can be efficiently aggregated.

  From the viewpoint of further increasing the insulation reliability more effectively and from the viewpoint of increasing the conduction reliability more effectively, the thermosetting compound preferably contains an epoxy compound.

  From the viewpoint of more effectively disposing the solder on the electrode, the thermosetting compound preferably includes a thermosetting compound having a polyether skeleton.

  Examples of the thermosetting compound having a polyether skeleton include a compound having a glycidyl ether group at both ends of an alkyl chain having 3 to 12 carbon atoms, and a polyether skeleton having 2 to 4 carbon atoms. Examples thereof include polyether type epoxy compounds having structural units in which 2 to 10 are bonded continuously.

  From the viewpoint of further effectively increasing the heat resistance of the cured product, the thermosetting compound preferably includes a thermosetting compound having an isocyanuric skeleton.

  Examples of the thermosetting compound having the above isocyanuric skeleton include triisocyanurate type epoxy compounds, etc., and TEPIC series (TEPIC-G, TEPIC-S, TEPIC-SS, TEPIC-HP, TEPIC-L, manufactured by Nissan Chemical Industries, Ltd.) TEPIC-PAS, TEPIC-VL, TEPIC-UC) and the like.

  In 100% by weight of the conductive material, the content of the thermosetting compound is preferably 5% by weight or more, more preferably 10% by weight or more, further preferably 15% by weight or more, and preferably 90% by weight or less. Preferably it is 70 weight% or less, More preferably, it is 50 weight% or less, Most preferably, it is 30 weight% or less. When the content of the thermosetting compound is not less than the above lower limit and not more than the above upper limit, the solder can be disposed more efficiently on the electrodes, and the insulation reliability between the electrodes can be further effectively improved. Further, the conduction reliability between the electrodes can be further effectively improved. From the viewpoint of more effectively increasing the impact resistance, it is preferable that the content of the thermosetting compound is large.

  In 100% by weight of the conductive material, the content of the epoxy compound is preferably 5% by weight or more, more preferably 10% by weight or more, further preferably 15% by weight or more, preferably 90% by weight or less, more preferably It is 70% by weight or less, more preferably 50% by weight or less, and particularly preferably 30% by weight or less. When the content of the epoxy compound is not less than the above lower limit and not more than the above upper limit, the solder can be more efficiently arranged on the electrodes, and the insulation reliability between the electrodes can be further effectively improved, The conduction reliability between them can be further effectively improved. From the viewpoint of further improving the impact resistance, it is preferable that the content of the epoxy compound is large.

(Thermosetting component: thermosetting agent)
The said thermosetting agent is not specifically limited. The thermosetting agent thermosets the thermosetting compound. Examples of the thermosetting agent include imidazole curing agents, amine curing agents, phenol curing agents, polythiol curing agents, and other thiol curing agents, acid anhydride curing agents, thermal cation initiators (thermal cation curing agents), and thermal radical generators. Is mentioned. As for the said thermosetting agent, only 1 type may be used and 2 or more types may be used together.

  From the viewpoint of allowing the conductive material to be cured more rapidly at a low temperature, the thermosetting agent is preferably an imidazole curing agent, a thiol curing agent, or an amine curing agent. Further, from the viewpoint of enhancing the storage stability when the thermosetting compound and the thermosetting agent are mixed, the thermosetting agent is preferably a latent curing agent. The latent curing agent is preferably a latent imidazole curing agent, a latent thiol 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. Examples of the imidazole curing agent include 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-triazine isocyanuric acid adducts 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4-benzyl-5-hydroxymethylimidazole, 2-paratoluyl-4-methyl-5 -Hydroxymethylimidazole, 2-metatoluyl-4-methyl-5- Roxymethylimidazole, 2-metatoluyl-4,5-dihydroxymethylimidazole, 2-paratoluyl-4,5-dihydroxymethylimidazole, etc., the hydrogen at the 5-position of 1H-imidazole is a hydroxymethyl group and the hydrogen at the 2-position Examples thereof include an imidazole compound substituted with a phenyl group or a toluyl group.

  The thiol curing agent is not particularly limited. Examples of the thiol curing agent include trimethylolpropane tris-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate, and dipentaerythritol hexa-3-mercaptopropionate.

  The amine curing agent is not particularly limited. Examples of the amine curing agent include hexamethylenediamine, octamethylenediamine, decamethylenediamine, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraspiro [5.5] undecane, bis (4 -Aminocyclohexyl) methane, metaphenylenediamine, diaminodiphenylsulfone and the like.

  The acid anhydride curing agent is not particularly limited and can be widely used as long as it is an acid anhydride used as a curing agent for a thermosetting compound such as an epoxy compound. Examples of the acid anhydride curing agent include phthalic anhydride, tetrahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride. Phthalic acid anhydride, maleic anhydride, nadic anhydride, methyl nadic anhydride, glutaric anhydride, succinic anhydride, glycerin bistrimellitic anhydride monoacetate, and ethylene glycol bistrimellitic anhydride Acid anhydride curing agent, trifunctional acid anhydride curing agent such as trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, methylcyclohexene tetracarboxylic acid anhydride, polyazeline acid anhydride, etc. 4 or more functional acid anhydrides Curing agents.

  The thermal cation initiator is not particularly limited. Examples of the thermal cation initiator include iodonium cation curing agents, oxonium cation curing agents, and sulfonium cation 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. Examples of the thermal radical generator 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 reaction initiation temperature of the thermosetting agent is preferably 50 ° C. or higher, more preferably 70 ° C. or higher, further preferably 80 ° C. or higher, preferably 250 ° C. or lower, more preferably 200 ° C. or lower, and further preferably 150 ° C. Hereinafter, it is particularly preferably 140 ° C. or lower. When the reaction start temperature of the thermosetting agent is not less than the above lower limit and not more than the above upper limit, the solder is more efficiently disposed on the electrode. The reaction start temperature of the thermosetting agent is particularly preferably 80 ° C. or higher and 140 ° C. or lower.

  From the viewpoint of more efficiently arranging the solder on the electrode, the reaction initiation temperature of the thermosetting agent is preferably higher than the melting point of the solder particles, more preferably 5 ° C or higher, more preferably 10 ° C. More preferably, it is higher.

  The reaction start temperature of the thermosetting agent means a temperature at which the exothermic peak of DSC starts to rise.

  The content of the thermosetting agent is not particularly limited. The content of the thermosetting agent with respect to 100 parts by weight of the thermosetting compound is preferably 0.01 parts by weight or more, more preferably 1 part by weight or more, preferably 200 parts by weight or less, more 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.

(Thermosetting component: curing accelerator)
The conductive material may contain a curing accelerator. The said hardening accelerator is not specifically limited. The curing accelerator preferably acts as a curing catalyst in the reaction between the thermosetting compound and the thermosetting agent. The curing accelerator preferably acts as a curing catalyst in the reaction with the thermosetting compound. As for the said hardening accelerator, only 1 type may be used and 2 or more types may be used together.

  Examples of the curing accelerator include phosphonium salts, tertiary amines, tertiary amine salts, quaternary onium salts, tertiary phosphines, crown ether complexes, and phosphonium ylides. Specifically, the curing accelerator includes imidazole compound, isocyanurate of imidazole compound, dicyandiamide, dicyandiamide derivative, melamine compound, melamine compound derivative, diaminomaleonitrile, diethylenetriamine, triethylenetetramine, tetraethylenepentamine. , Amine compounds such as bis (hexamethylene) triamine, triethanolamine, diaminodiphenylmethane, organic acid dihydrazide, 1,8-diazabicyclo [5,4,0] undecene-7, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, boron trifluoride, and triphenylphosphine, tricyclohexylphosphine, tributylphosphine and methyldiphenylphosphine And the like organic phosphorus compounds.

  The phosphonium salt is not particularly limited. Examples of the phosphonium salt include tetranormal butylphosphonium bromide, tetranormal butylphosphonium O, O-diethyldithiophosphoric acid, methyl tributylphosphonium dimethyl phosphate, tetranormal butylphosphonium benzotriazole, tetranormal butylphosphonium tetrafluoroborate, and tetranormal borates. And butylphosphonium tetraphenylborate.

  The content of the curing accelerator is appropriately selected so that the thermosetting compound is cured well. The content of the curing accelerator with respect to 100 parts by weight of the thermosetting compound is preferably 0.5 parts by weight or more, more preferably 0.8 parts by weight or more, preferably 10 parts by weight or less, more preferably 8 parts by weight. Less than parts by weight. When the content of the curing accelerator is not less than the above lower limit and not more than the above upper limit, the thermosetting compound can be cured well.

(flux)
The conductive material may contain a flux. By using the flux, the solder can be arranged more efficiently on the electrode. The flux is not particularly limited. As said flux, the flux generally used for soldering etc. 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 amine compound, an organic acid, and Examples include pine resin. 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 or pine resin. The flux may be an organic acid having two or more carboxyl groups, or pine resin. Use of an organic acid having two or more carboxyl groups and pine resin further increases the reliability of conduction between the electrodes.

  Examples of the organic acid having two or more carboxyl groups include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid.

  Examples of the amine compound include cyclohexylamine, dicyclohexylamine, benzylamine, benzhydrylamine, imidazole, benzimidazole, phenylimidazole, carboxybenzimidazole, benzotriazole, and carboxybenzotriazole.

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

  The active temperature (melting point) of the flux is preferably 50 ° C. or higher, more preferably 70 ° C. or higher, further preferably 80 ° C. or higher, preferably 200 ° C. or lower, more preferably 190 ° C. or lower, and still more preferably 160 ° C or lower, more preferably 150 ° C or lower, still more preferably 140 ° C or lower. When the activation temperature of the flux is not less than the above lower limit and not more than the above upper limit, the flux effect is more effectively exhibited, and the solder is more efficiently arranged on the electrode. The active temperature (melting point) of the flux is preferably 80 ° C. or higher and 190 ° C. or lower. The activation temperature (melting point) of the flux is particularly preferably 80 ° C. or higher and 140 ° C. or lower.

  Examples of the flux having an active temperature (melting point) of 80 to 190 ° C. include succinic acid (melting point 186 ° C.), glutaric acid (melting point 96 ° C.), adipic acid (melting point 152 ° C.), pimelic acid (melting point 104 And dicarboxylic acids such as suberic acid (melting point 142 ° C.), benzoic acid (melting point 122 ° C.), malic acid (melting point 130 ° C.), and the like.

  The boiling point of the flux is preferably 200 ° C. or lower.

  From the viewpoint of more efficiently arranging the solder on the electrode, the melting point of the flux is preferably higher than the melting point of the solder particles, more preferably 5 ° C or more, and more preferably 10 ° C or more. Further preferred.

  From the viewpoint of more efficiently arranging the solder on the electrode, the melting point of the flux is preferably higher than the reaction start temperature of the thermosetting agent, more preferably 5 ° C or higher, more preferably 10 ° C or higher. More preferably, it is high.

  The said flux may be disperse | distributed in the electrically-conductive material and may adhere on the surface of electroconductive particle.

  When the melting point of the flux is higher than the melting point of the solder particles, the solder can be efficiently aggregated on the electrode portion. This is because, when heat is applied at the time of joining, when the electrode formed on the connection target member is compared with the portion of the connection target member around the electrode, the thermal conductivity of the electrode portion is that of the connection target member portion around the electrode. Due to the fact that it is higher than the thermal conductivity, the temperature rise of the electrode portion is fast. At the stage where the melting point of the solder particles is exceeded, the inside of the solder dissolves, but the oxide film formed on the surface does not reach the melting point (activation temperature) of the flux and is not removed. In this state, since the temperature of the electrode portion first reaches the melting point (activation temperature) of the flux, the oxide film on the surface of the solder moved on the electrode is removed preferentially, and the solder spreads on the surface of the electrode. be able to. Thereby, a solder can be efficiently aggregated on an electrode.

  The flux is preferably a flux that releases cations by heating. By using a flux that releases cations by heating, the solder can be arranged more efficiently on the electrode.

  Examples of the flux that releases cations by the heating include the thermal cation initiator (thermal cation curing agent).

  From the viewpoint of more efficiently arranging the solder on the electrode, the viewpoint of increasing the insulation reliability more effectively, and the viewpoint of improving the conduction reliability more effectively, the above flux is composed of an acid compound and a base compound. And a salt thereof.

  The acid compound is preferably an organic compound having a carboxyl group. Examples of the acid compound include aliphatic carboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, citric acid, malic acid, and cyclic aliphatic carboxylic acid. Examples thereof include cyclohexyl carboxylic acid, 1,4-cyclohexyl dicarboxylic acid, aromatic carboxylic acid such as isophthalic acid, terephthalic acid, trimellitic acid, and ethylenediaminetetraacetic acid. From the viewpoint of more efficiently arranging the solder on the electrode, the viewpoint of increasing the insulation reliability more effectively, and the viewpoint of further improving the conduction reliability more effectively, the acid compound is glutaric acid, cyclohexyl. Carboxylic acid or adipic acid is preferred.

  The base compound is preferably an organic compound having an amino group. Examples of the base compound include diethanolamine, triethanolamine, methyldiethanolamine, ethyldiethanolamine, cyclohexylamine, dicyclohexylamine, benzylamine, benzhydrylamine, 2-methylbenzylamine, 3-methylbenzylamine, 4-tert-butylbenzylamine. N-methylbenzylamine, N-ethylbenzylamine, N-phenylbenzylamine, N-tert-butylbenzylamine, N-isopropylbenzylamine, N, N-dimethylbenzylamine, imidazole compounds, and triazole compounds. . From the viewpoint of more efficiently arranging the solder on the electrode, the viewpoint of increasing the insulation reliability more effectively, and the viewpoint of further improving the conduction reliability more effectively, the base compound is benzylamine. It is preferable.

  The content of the flux in 100% by weight of the conductive material is 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 content of the flux is not less than the above lower limit and not more than the above upper limit, it is more difficult to form an oxide film on the surface of the solder and the electrode, and further, the oxide film formed on the surface of the solder and the electrode is further increased. Can be effectively removed.

(Filler)
The conductive material according to the present invention may contain a filler. The filler may be an organic filler or an inorganic filler. When the conductive material contains a filler, the solder can be uniformly aggregated over all the electrodes of the substrate.

  It is preferable that the conductive material does not contain the filler or contains the filler at 5% by weight or less. When the thermosetting compound is used, the smaller the filler content, the easier the solder moves on the electrode.

  The content of the filler in 100% by weight of the conductive material is preferably 0% by weight (not contained) or more, preferably 5% by weight or less, more preferably 2% by weight or less, and further preferably 1% by weight or less. is there. When the content of the filler is not less than the above lower limit and not more than the above upper limit, the solder is more uniformly arranged on the electrode.

(Other ingredients)
The conductive material may be, for example, a filler, an extender, a softener, a plasticizer, a thixotropic agent, a leveling agent, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, and a light stabilizer. In addition, various additives such as ultraviolet absorbers, lubricants, antistatic agents and flame retardants may be contained.

(Connection structure and method of manufacturing connection structure)
The connection structure according to the present invention includes a first connection target member having a first electrode on the surface, a second connection target member having a second electrode on the surface, the first connection target member, A connecting portion connecting the second connection target member. In the connection structure according to the present invention, the material of the connection portion is the conductive material described above. In the connection structure according to the present invention, the first electrode and the second electrode are electrically connected by a solder portion in the connection portion.

  The manufacturing method of the connection structure which concerns on this invention comprises the process of arrange | positioning the said electrically-conductive material on the surface of the 1st connection object member which has a 1st electrode on the surface using the electrically conductive material mentioned above. In the method for manufacturing a connection structure according to the present invention, a second connection target member having a second electrode on a surface thereof is provided on the surface opposite to the first connection target member side of the conductive material. A step of disposing the first electrode and the second electrode so as to face each other. In the method for manufacturing a connection structure according to the present invention, the connection that connects the first connection target member and the second connection target member by heating the conductive material to a temperature equal to or higher than the melting point of the solder particles. Forming a portion with the conductive material and electrically connecting the first electrode and the second electrode with a solder portion in the connection portion.

  In the connection structure and the manufacturing method of the connection structure according to the present invention, since a specific conductive material is used, the solder is likely to gather between the first electrode and the second electrode, and the solder is an electrode (line). Can be efficiently placed on top. In addition, a part of the solder is difficult to be disposed in a region (space) where no electrode is formed, and the amount of solder disposed in a region where no electrode is formed can be considerably reduced. Therefore, the conduction reliability between the first electrode and the second electrode can be improved. In addition, it is possible to prevent electrical connection between laterally adjacent electrodes that should not be connected, and to improve insulation reliability.

  Moreover, in order to dispose the solder efficiently on the electrode and to considerably reduce the amount of the solder disposed in the region where the electrode is not formed, the conductive material is not a conductive film but a conductive paste. It is preferable.

  The thickness of the solder part between the electrodes is preferably 10 μm or more, more preferably 20 μm or more, preferably 100 μm or less, more preferably 80 μm or less. The solder wetted area on the surface of the electrode (area where the solder is in contact with 100% of the exposed area of the electrode) is preferably 50% or more, more preferably 70% or more, and preferably 100% or less.

  In the method for manufacturing a connection structure according to the present invention, in the step of arranging the second connection target member and the step of forming the connection portion, no pressure is applied, and the second connection is applied to the conductive material. The weight of the target member is preferably added. In the method for manufacturing a connection structure according to the present invention, in the step of disposing the second connection target member and the step of forming the connection portion, the conductive material has a weight force of the second connection target member. It is preferable not to apply a pressure higher than. In these cases, the uniformity of the amount of solder can be further enhanced in the plurality of solder portions. Furthermore, the thickness of the solder portion can be increased more effectively, so that a large amount of solder is easily collected between the electrodes, and the solder can be arranged more efficiently on the electrodes (lines). Further, a part of the solder is difficult to be disposed in a region (space) where no electrode is formed, and the amount of solder disposed in a region where no electrode is formed can be further reduced. Therefore, the conduction reliability between the electrodes can be further enhanced. In addition, the electrical connection between the laterally adjacent electrodes that should not be connected can be further prevented, and the insulation reliability can be further improved.

  Moreover, if a conductive paste is used instead of a conductive film, it becomes easy to adjust the thickness of the connection part and the solder part depending on the amount of the conductive paste applied. On the other hand, in the conductive film, in order to change or adjust the thickness of the connecting portion, it is necessary to prepare a conductive film having a different thickness or to prepare a conductive film having a predetermined thickness. There is. Moreover, in the conductive film, compared with the conductive paste, the melt viscosity of the conductive film cannot be sufficiently lowered at the melting temperature of the solder, and the aggregation of the solder tends to be hindered.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view schematically showing a connection structure obtained using a conductive material according to an embodiment of the present invention.

  The connection structure 1 shown in FIG. 1 is a connection that connects a first connection target member 2, a second connection target member 3, and the first connection target member 2 and the second connection target member 3. Part 4. The connection part 4 is formed of the conductive material described above. In the present embodiment, the conductive material includes a thermosetting component and a plurality of conductive particles. The thermosetting component includes a thermosetting compound and a thermosetting agent. The conductive particles include solder particles. In the present embodiment, a conductive paste is used as the conductive material.

  The connection portion 4 includes a solder portion 4A in which a plurality of solder particles are gathered and joined to each other, and a cured product portion 4B in which a thermosetting compound is thermally cured.

  The first connection target member 2 has a plurality of first electrodes 2a on the surface (upper surface). The second connection target member 3 has a plurality of second electrodes 3a on the surface (lower surface). The first electrode 2a and the second electrode 3a are electrically connected by the solder portion 4A. Therefore, the first connection target member 2 and the second connection target member 3 are electrically connected by the solder portion 4A. In the connection portion 4, no solder particles are present in a region (cured product portion 4B portion) different from the solder portion 4A gathered between the first electrode 2a and the second electrode 3a. In an area different from the solder part 4A (hardened product part 4B part), there are no solder particles separated from the solder part 4A. If the amount is small, solder particles may exist in a region (cured product portion 4B portion) different from the solder portion 4A gathered between the first electrode 2a and the second electrode 3a.

  As shown in FIG. 1, in the connection structure 1, a plurality of solder particles gather between the first electrode 2 a and the second electrode 3 a, and after the plurality of solder particles melt, After the electrode surface wets and spreads, it solidifies to form the solder portion 4A. For this reason, the connection area of 4 A of solder parts and the 1st electrode 2a, and 4 A of solder parts, and the 2nd electrode 3a becomes large. That is, by using the solder particles, the solder portion 4A, the first electrode 2a, and the solder portion are compared with the case where the conductive outer surface is made of a metal such as nickel, gold or copper. The contact area between 4A and the second electrode 3a increases. This also increases the conduction reliability and connection reliability in the connection structure 1. In addition, when a flux is contained in the conductive material, the flux is generally gradually deactivated by heating.

  In addition, in the connection structure 1 shown in FIG. 1, all the solder parts 4A are located in the area | region which the 1st, 2nd electrodes 2a and 3a oppose. The connection structure 1X of the modification shown in FIG. 3 is different from the connection structure 1 shown in FIG. 1 only in the connection portion 4X. The connection part 4X has the solder part 4XA and the hardened | cured material part 4XB. As in the connection structure 1X, most of the solder portions 4XA are located in regions where the first and second electrodes 2a and 3a are opposed to each other, and a part of the solder portion 4XA is first and second. You may protrude to the side from the area | region which electrode 2a, 3a has opposed. The solder part 4XA protruding laterally from the region where the first and second electrodes 2a and 3a are opposed is a part of the solder part 4XA and is not a solder particle separated from the solder part 4XA. In this embodiment, the amount of solder particles separated from the solder portion can be reduced, but the solder particles separated from the solder portion may be present in the cured product portion.

  If the amount of solder particles used is reduced, the connection structure 1 can be easily obtained. If the amount of the solder particles used is increased, it becomes easy to obtain the connection structure 1X.

  In connection structure 1, 1X, when the part which 1st electrode 2a and 2nd electrode 3a oppose in the lamination direction of 1st electrode 2a, connection part 4, 4X, and 2nd electrode 3a is seen In addition, it is preferable that the solder portions 4A and 4XA in the connection portions 4 and 4X are arranged in 50% or more of the area of 100% of the facing portion between the first electrode 2a and the second electrode 3a. . When the solder portions 4A and 4XA in the connection portions 4 and 4X satisfy the above-described preferable mode, the conduction reliability can be further improved.

  When the first electrode and the second electrode face each other in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the second electrode It is preferable that the solder portion in the connecting portion is arranged in 50% or more of the area of 100% of the portion facing the two electrodes. When the first electrode and the second electrode face each other in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the second electrode It is more preferable that the solder portion in the connection portion is disposed in 60% or more of 100% of the area of the portion facing the two electrodes. When the first electrode and the second electrode face each other in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the second electrode More preferably, the solder portion in the connecting portion is arranged in 70% or more of the area of 100% of the portion facing the two electrodes. When the first electrode and the second electrode face each other in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the second electrode It is particularly preferable that the solder portion in the connecting portion is disposed in 80% or more of 100% of the area facing the two electrodes. When the first electrode and the second electrode face each other in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the second electrode It is most preferable that the solder portion in the connection portion is disposed in 90% or more of the area of 100% of the portion facing the two electrodes. When the solder part in the connection part satisfies the above-described preferable aspect, the conduction reliability can be further improved.

  When the portion where the first electrode and the second electrode face each other in the direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode is seen, It is preferable that 60% or more of the solder portion in the connection portion is disposed in a portion where the electrode and the second electrode face each other. When the portion where the first electrode and the second electrode face each other in the direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode is seen, More preferably, 70% or more of the solder portion in the connection portion is disposed in a portion where the electrode and the second electrode face each other. When the portion where the first electrode and the second electrode face each other in the direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode is seen, More preferably, 90% or more of the solder portion in the connection portion is disposed in a portion where the electrode and the second electrode face each other. When the portion where the first electrode and the second electrode face each other in the direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode is seen, It is particularly preferable that 95% or more of the solder portion in the connection portion is disposed at a portion where the electrode and the second electrode face each other. When the portion where the first electrode and the second electrode face each other in the direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode is seen, It is most preferable that 99% or more of the solder portion in the connection portion is disposed in a portion where the electrode and the second electrode face each other. When the solder part in the connection part satisfies the above-described preferable aspect, the conduction reliability can be further improved.

  Next, FIG. 2 illustrates an example of a method for manufacturing the connection structure 1 using the conductive material according to the embodiment of the present invention.

  First, the 1st connection object member 2 which has the 1st electrode 2a on the surface (upper surface) is prepared. Next, as illustrated in FIG. 2A, the conductive material 11 including the thermosetting component 11 </ b> B and a plurality of conductive particles is disposed on the surface of the first connection target member 2 (the first connection target member 2). Process). The used conductive material 11 contains a thermosetting compound and a thermosetting agent as the thermosetting component 11B. In the conductive material 11 used, the conductive particles include solder particles 11A and solder particles 11C having a melting point higher than that of the solder particles 11A.

  The conductive material 11 is disposed on the surface of the first connection target member 2 on which the first electrode 2a is provided. After the arrangement of the conductive material 11, the solder particles 11A and the solder particles 11C are arranged both on the first electrode 2a (line) and on the region (space) where the first electrode 2a is not formed. Yes.

  The arrangement method of the conductive material 11 is not particularly limited, and examples thereof include application using a dispenser, screen printing, and ejection using an inkjet apparatus.

  Moreover, the 2nd connection object member 3 which has the 2nd electrode 3a on the surface (lower surface) is prepared. Next, as shown in FIG. 2B, in the conductive material 11 on the surface of the first connection target member 2, on the surface opposite to the first connection target member 2 side of the conductive material 11, The 2nd connection object member 3 is arrange | positioned (2nd process). On the surface of the conductive material 11, the second connection target member 3 is disposed from the second electrode 3a side. At this time, the first electrode 2a and the second electrode 3a are opposed to each other.

  Next, the conductive material 11 is heated above the melting point of the solder particles 11A (third step). Preferably, the conductive material 11 is heated above the curing temperature of the thermosetting component 11B (thermosetting compound). At the time of this heating, the solder particles 11A and the solder particles 11C that existed in the region where the electrodes are not formed gather between the first electrode 2a and the second electrode 3a (self-aggregation effect). When the conductive paste is used instead of the conductive film, the solder particles 11A and the solder particles 11C are more effectively collected between the first electrode 2a and the second electrode 3a. Also, the solder particles 11A and the solder particles 11C are melted and joined to each other. Further, the thermosetting component 11B is thermoset. As a result, as shown in FIG. 2C, the connection portion 4 that connects the first connection target member 2 and the second connection target member 3 is formed of the conductive material 11. The connection part 4 is formed by the conductive material 11, the solder part 4A is formed by joining the plurality of solder particles 11A and the solder particles 11C, and the cured part 4B is formed by thermosetting the thermosetting component 11B. The If the solder particles 11A and the solder particles 11C are sufficiently moved, the movement of the solder particles 11A and the solder particles 11C that are not positioned between the first electrode 2a and the second electrode 3a is started. The temperature may not be kept constant until the movement of the solder particles 11A and the solder particles 11C is completed between the second electrode 3a and the second electrode 3a.

  In the present embodiment, it is preferable that no pressure is applied in the second step and the third step. In this case, the weight of the second connection target member 3 is added to the conductive material 11. For this reason, when the connection part 4 is formed, the solder particles 11A and the solder particles 11C are more effectively collected between the first electrode 2a and the second electrode 3a. If at least one of the second process and the third process is pressurized, the solder particles 11A and the solder particles 11C are collected between the first electrode 2a and the second electrode 3a. There is a higher tendency for the action to be blocked to be inhibited.

  Moreover, in this embodiment, since pressurization is not performed, the first connection target member 2 and the second connection target member 3 are in a state where the alignment between the first electrode 2a and the second electrode 3a is shifted. Can be corrected, the first electrode 2a and the second electrode 3a can be connected (self-alignment effect). This is because the molten solder self-aggregating between the first electrode 2a and the second electrode 3a is different from the solder between the first electrode 2a and the second electrode 3a and other conductive materials. This is because, when the area in contact with the component is minimized, the energy becomes more stable, and thus the force for forming the aligned connection structure, which is the connection structure having the minimum area, acts. At this time, it is desirable that the conductive material is not cured and that the viscosity of components other than the solder particles of the conductive material is sufficiently low at that temperature and time.

  The viscosity of the conductive material at the melting point of the solder particles is preferably 50 Pa · s or less, more preferably 10 Pa · s or less, still more preferably 1 Pa · s or less, preferably 0.1 Pa · s or more, more preferably 0. .2 Pa · s or more. If the said viscosity is below the said upper limit, a solder can be efficiently aggregated on an electrode. If the said viscosity is more than the said minimum, the void in a connection part can be suppressed and the protrusion of the electrically-conductive material other than a connection part can be suppressed.

  The viscosity of the conductive material at the melting point of the solder particles is as follows: STRESSTECH (manufactured by REOLOGICA), etc., strain control 1 rad, frequency 1 Hz, heating rate 20 ° C./min, measurement temperature range 25 ° C. to 200 ° C. (however, When the melting point of the solder particles exceeds 200 ° C., the upper limit of the temperature is taken as the melting point of the solder particles). From the measurement results, the viscosity of the solder particles at the melting point (° C.) is evaluated.

  In this way, the connection structure 1 shown in FIG. 1 is obtained. The second step and the third step may be performed continuously. Moreover, after performing the said 2nd process, the laminated body of the 1st connection object member 2, the electrically-conductive material 11, and the 2nd connection object member 3 which are obtained is moved to a heating part, and the said 3rd connection object is carried out. You may perform a process. In order to perform the heating, the laminate may be disposed on a heating member, or the laminate may be disposed in a heated space.

  The heating temperature in the third step is preferably 140 ° C. or higher, more preferably 160 ° C. or higher, preferably 450 ° C. or lower, more preferably 250 ° C. or lower, and even more preferably 200 ° C. or lower.

  As the heating method in the third step, a method of heating the entire connection structure using a reflow furnace or an oven above the melting point of the solder particles and the curing temperature of the thermosetting component, or a connection structure The method of heating only the connection part of a body locally is mentioned.

  As a tool used for the method of heating locally, a hot plate, a heat gun for applying hot air, a soldering iron, an infrared heater, and the like can be given.

  In addition, when heating locally with a hot plate, the metal directly under the connection is made of a metal with high thermal conductivity, and other places where heating is not preferred are made of a material with low thermal conductivity such as a fluororesin. The upper surface of the hot plate is preferably formed.

  The said 1st, 2nd connection object member is not specifically limited. Specifically as said 1st, 2nd connection object member, electronic components, such as a semiconductor chip, a semiconductor package, LED chip, LED package, a capacitor | condenser, a diode, and a resin film, a printed circuit board, a flexible printed circuit board, flexible Examples thereof include electronic components such as circuit boards such as flat cables, rigid flexible boards, glass epoxy boards, and glass boards. The first and second connection target members are preferably electronic components.

  It is preferable that at least one of the first connection target member and the second connection target member is a resin film, a flexible printed board, a flexible flat cable, or a rigid flexible board. The second connection target member is preferably a resin film, a flexible printed board, a flexible flat cable, or a rigid flexible board. Resin films, flexible printed boards, flexible flat cables, and rigid flexible boards have the property of being highly flexible and relatively lightweight. When a conductive film is used for connection of such a connection object member, there exists a tendency for a solder not to gather on an electrode. On the other hand, by using a conductive paste, even if a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible circuit board is used, the conductive reliability between the electrodes can be efficiently collected by collecting the solder on the electrodes. Can be increased sufficiently. When using a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible circuit board, compared to the case of using other connection target members such as a semiconductor chip, the conduction reliability between the electrodes by not applying pressure is improved. The improvement effect can be obtained more effectively.

  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, a silver electrode, a SUS 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, a silver 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, a silver 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.

  In the connection structure according to the present invention, it is preferable that the first electrode and the second electrode are arranged in an area array or a peripheral. In the case where the first electrode and the second electrode are arranged in an area array or a peripheral, the effect of the present invention is more effectively exhibited. The area array is a structure in which electrodes are arranged in a grid pattern on the surface on which the electrodes of the connection target members are arranged. The peripheral is a structure in which electrodes are arranged on the outer periphery of a connection target member. In the case of a structure in which the electrodes are arranged in a comb shape, the solder may be aggregated along the direction perpendicular to the comb, whereas in the area array or the peripheral structure, the electrode is disposed on the entire surface. It is necessary that the solder agglomerates uniformly. Therefore, in the conventional method, the amount of solder tends to be non-uniform, whereas in the method of the present invention, the effect of the present invention is more effectively exhibited.

  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.

Thermosetting component (thermosetting compound):
Thermosetting compound 1: Bisphenol F type epoxy compound, “YDF-8170C” manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.
Thermosetting compound 2: bisphenol A type epoxy compound, “YD-8125” manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.
Thermosetting compound 3: phenol novolac type epoxy compound, “DEN431” manufactured by DOW
Thermosetting compound 4: Aliphatic epoxy compound, “Epolite 1600” manufactured by Kyoeisha Chemical Co., Ltd.
Thermosetting compound 5: epoxy compound containing isocyanuric skeleton, “TEPIC-SP” manufactured by Nissan Chemical Co., Ltd.

Thermosetting component (thermosetting agent):
Thermosetting agent 1: Acid anhydride curing agent, “Ricacid MH” manufactured by Shin Nippon Chemical Co., Ltd.
Thermosetting agent 2: Acid anhydride curing agent, “Ricacid TH” manufactured by Shin Nippon Chemical Co., Ltd.

Thermosetting component (curing accelerator):
Curing accelerator 1: Organic phosphonium salt, “PX-4MP” manufactured by Nippon Chemical Industry Co., Ltd.
flux:
Flux 1: “Benzylamine glutarate”, melting point 108 ° C.
Preparation method of flux 1:
In a glass bottle, 24 g of water as a reaction solvent and 13.212 g of glutaric acid (manufactured by Wako Pure Chemical Industries, Ltd.) were added and dissolved until uniform at room temperature. Thereafter, 10.715 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred for about 5 minutes to obtain a mixed solution. The obtained mixed solution was put in a refrigerator at 5 to 10 ° C. and left overnight. The precipitated crystals were collected by filtration, washed with water, and vacuum-dried to obtain flux 1.

Conductive particles (solder particles, conductive particles other than solder particles (conductive particles X)):
Solder particles 1: SnBi solder particles, melting point 138 ° C., solder particles selected from Mitsui Kinzoku “Sn42Bi58”, average particle diameter: 30 μm
Solder particles 2: SnBi solder particles, melting point 138 ° C., solder particles selected from Mitsui Kinzoku “Sn42Bi58”, average particle diameter: 10 μm
Solder particles 3: SnBi solder particles, melting point 138 ° C., solder particles selected from Mitsui Kinzoku “Sn42Bi58”, average particle diameter: 5 μm
Solder particles 4: SnBi solder particles, melting point 138 ° C., solder particles selected from Mitsui Kinzoku Co., Ltd. “Sn42Bi58”, average particle diameter: 2 μm
Solder particles 5: SnAgCu solder particles, “SnAg3Cu0.5” manufactured by Mitsui Mining & Smelting Co., Ltd., average particle size: 30 μm, melting point: 217 ° C.
Solder particles 6: SnAgCu solder particles, “SnAg3Cu0.5” manufactured by Mitsui Mining & Smelting Co., Ltd., average particle size: 10 μm, melting point: 217 ° C.
Solder particles 7: SnAgCu solder particles, “SnAg3Cu0.5” manufactured by Mitsui Mining & Smelting Co., Ltd., average particle size: 5 μm, melting point: 217 ° C.
Solder particles 8: SnAgCu solder particles, “SnAg3Cu0.5” manufactured by Mitsui Mining & Smelting Co., Ltd., average particle size: 2 μm, melting point: 217 ° C.
Conductive particles X1: Ag-coated copper powder, “10% Ag / 08K2” manufactured by Mitsui Kinzoku Co., Ltd., average particle size: 10 μm

(Examples 1 to 26 and Comparative Example 1)
(1) Preparation of conductive material (anisotropic conductive paste) The components shown in the following Tables 1 and 2 are blended in the blending amounts shown in Tables 1 and 2 to obtain a conductive material (anisotropic conductive paste). It was.

(2) Production of connection structure As a first connection target member, a glass epoxy substrate (material: FR−) having a copper electrode (electrode length: 3 mm, electrode thickness: 12 μm) of L / S = 50 μm / 50 μm on the surface. 4, thickness: 0.6 mm).

  As a second connection target member, a flexible printed circuit board (material: polyimide, thickness: 0.1 mm) having a copper electrode (electrode length: 3 mm, electrode thickness: 12 μm) of L / S = 50 μm / 50 μm is prepared. did.

  A conductive material (anisotropic conductive paste) immediately after fabrication was applied to the upper surface of the glass epoxy substrate so as to have a thickness of 100 μm, thereby forming a conductive material (anisotropic conductive paste) layer. Next, a flexible printed circuit board was laminated on the upper surface of the conductive material (anisotropic conductive paste) layer so that the electrodes face each other. The weight of the flexible printed circuit board is added to the conductive material (anisotropic conductive paste) layer. From this state, the conductive material (anisotropic conductive paste) layer was heated so that the temperature of the conductive material (anisotropic conductive paste) layer became the melting point of the solder particles 5 seconds after the start of temperature increase. Further, after 15 seconds from the start of temperature increase, the conductive material (anisotropic conductive paste) layer is heated to a temperature of 160 ° C. to cure the conductive material (anisotropic conductive paste) layer. Obtained. No pressure was applied during heating.

(Evaluation)
(1) Wetting time when the conductive material is heated from 25 ° C. to 160 ° C. at 1.0 ° C./sec. Wetting time when the conductive material is heated from 25 ° C. to 160 ° C. at 1.0 ° C./sec. The time was measured using a solder wettability tester as follows. As the solder wettability tester, “Wettability tester (SP2)” manufactured by Malcolm Co. was used.

(Measurement method of wetting time when conductive material is heated from 25 ° C to 160 ° C at 1.0 ° C / second)
The wetting time of the conductive material was measured by the meniscograph method. After supplying the obtained conductive material on the stage of the wettability tester (diameter 8 mm, thickness 0.3 μm), the test piece (3 mm × 10 mm × 0.3 mm) was lowered at room temperature and immersed in the conductive material. . After the immersion, the stage was heated at a heating rate of 1 ° C./second. After the stage reached 160 ° C., it was held for 3 seconds. After completion of the measurement, the wetting time was calculated from the difference between the time when wetting started and the time when it reached 2/3 times the maximum wetting force. About the obtained graph, the straight line which extended the base line of the curve which shows a wetting force was drawn. The time at the first intersection of the straight line and the curve indicating the wetting force was calculated as the time when wetting started. For the obtained graph, the maximum wetting force when the wetting force reached equilibrium was defined as the maximum wetting force. A straight line which is 2/3 times the maximum wetting force in the obtained graph and which is parallel to the straight line obtained by extending the base line was drawn. The time at the last intersection of the straight line and the curve showing the wetting force up to the maximum wetting force was calculated as the time when it reached 2/3 times the maximum wetting force. In the curve indicating the wetting force, the peak that appears before the wetting force reaches equilibrium was treated as a noise peak. When a noise peak appeared on the curve indicating the wetting force, the maximum wetting force was calculated without considering the noise peak.

(2) Wetting force of the conductive material at 160 ° C. The wetting force of the conductive material at 160 ° C. was measured using a solder wettability tester as follows. As the solder wettability tester, “Wettability tester (SP2)” manufactured by Malcolm Co. was used.

(Measurement method of wetting force of conductive material at 160 ° C)
The wetting time of the conductive material was measured by the meniscograph method. After supplying the obtained conductive material on the stage of the wettability tester (diameter 8 mm, thickness 0.3 μm), the test piece (3 mm × 10 mm × 0.3 mm) was lowered at room temperature and immersed in the conductive material. . After the immersion, the stage was heated at a heating rate of 1 ° C./second. After the stage reached 160 ° C., it was held for 3 seconds. After the measurement, the maximum wetting force in the obtained graph was calculated as the wetting force at 160 ° C.

(3) Solder placement accuracy on the electrode In the obtained connection structure, the first electrode and the second electrode face each other in the stacking direction of the first electrode, the connection portion, and the second electrode. When the portion was viewed, the ratio X of the area where the solder portion in the connection portion was arranged in the area of 100% of the portion where the first electrode and the second electrode face each other was evaluated. The placement accuracy of the solder on the electrode was determined according to the following criteria.

[Criteria for solder placement accuracy on electrodes]
○○○: Ratio X is 90% or more ○○: Ratio X is 80% or more and less than 90% ○: Ratio X is 70% or more and less than 80% ×: Ratio X is less than 70%

  The results are shown in Tables 1 and 2 below.

  The same tendency was observed even when using a resin film, a flexible flat cable, and a rigid flexible substrate.

DESCRIPTION OF SYMBOLS 1,1X ... Connection structure 2 ... 1st connection object member 2a ... 1st electrode 3 ... 2nd connection object member 3a ... 2nd electrode 4, 4X ... Connection part 4A, 4XA ... Solder part 4B, 4XB ... cured material part 11 ... conductive material 11A, 11C ... solder particle 11B ... thermosetting component 21 ... conductive particle 31 ... conductive particle 32 ... base particle 33 ... conductive part 33A ... second conductive part 33B ... first Conductive part 41 ... conductive particles 42 ... conductive part

Claims (12)

Including a thermosetting component and a plurality of conductive particles;
The conductive particles include solder particles;
A conductive material having a wetting time of 3 seconds to 25 seconds when heated from 25 ° C. to 160 ° C. at a rate of 1.0 ° C./second.   The conductive material according to claim 1, wherein the wetting time when the temperature is raised from 25 ° C. to 160 ° C. at 1.0 ° C./second is 5 seconds or more and 17 seconds or less.   The conductive material according to claim 1 or 2, wherein the wetting force at 160 ° C is 1.5 mN or more and 3.4 mN or less.   The conductive material according to any one of claims 1 to 3, wherein a content of the conductive particles is 40% by weight or more and 90% by weight or less in 100% by weight of the conductive material.   5. The conductive material according to claim 1, wherein the content of the solder particles is 50% by weight or more in 100% by weight of the conductive particles.   The conductive material according to claim 1, wherein a particle diameter of the solder particles is 0.01 μm or more and 30 μm or less.   The conductive material according to claim 1, wherein a melting point of the solder particles is 139 ° C. or higher and 221 ° C. or lower.   The conductive material according to claim 1, which is a conductive paste. A first connection object member having a first electrode on its surface;
A second connection target member having a second electrode on its surface;
A connecting portion connecting the first connection target member and the second connection target member;
The material of the connection part is the conductive material according to any one of claims 1 to 8,
A connection structure in which the first electrode and the second electrode are electrically connected by a solder portion in the connection portion.   When the first electrode and the second electrode face each other in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the second electrode 10. The connection structure according to claim 9, wherein the solder portion in the connection portion is arranged in 50% or more of the area of 100% of the portion facing the two electrodes. Using the conductive material according to claim 1, disposing the conductive material on the surface of the first connection target member having the first electrode on the surface;
On the surface opposite to the first connection target member side of the conductive material, the second connection target member having the second electrode on the surface is opposed to the first electrode and the second electrode. A step of arranging to
By heating the conductive material to a temperature equal to or higher than the melting point of the solder particles, a connection part connecting the first connection target member and the second connection target member is formed of the conductive material, and The manufacturing method of a connection structure provided with the process of electrically connecting a said 1st electrode and a said 2nd electrode with the solder part in the said connection part.   When the first electrode and the second electrode face each other in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the second electrode The manufacturing method of the connection structure of Claim 11 which obtains the connection structure by which the solder part in the said connection part is arrange | positioned in 50% or more out of 100% of the area of the part which opposes two electrodes .